"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"uuid:8a8bb162-9a18-4345-ad1e-2a9b9d8eb3e1","http://resolver.tudelft.nl/uuid:8a8bb162-9a18-4345-ad1e-2a9b9d8eb3e1","Multi-Modelling of the Managed Aquifer Recharge Systems for Sustainable Groundwater Development in Beijing Plain, China","Liu, S. (TU Delft Water Resources)","McClain, M.E. (promotor); Zhou, Yangxiao (copromotor); Delft University of Technology (degree granting institution); IHE Delft Institute for Water Education (degree granting institution)","2026","This study explores the challenge of groundwater depletion in the Beijing Plain, a problem exacerbated by rapid socio-economic expansion and unsustainable groundwater abstraction. The core of this research is the development and application of multi-scale numerical groundwater flow and transport models to rigorously evaluate the measures implemented by the Beijing municipality. These measures include the strategic reduction of groundwater abstraction and the adoption of innovative water management practices such as Managed Aquifer Recharge (MAR) and Environmental Flow Release (EFR) operations. Through the development of various hydrogeological conceptual models and a number of multi-scale flow and transport models, the study has successfully simulated groundwater storage depletion in the past and assessed the long-term sustainability of groundwater resources, taking into account the impact of current measures and future climate changes. The findings highlight the crucial role of MAR operations in restoring depleted groundwater storage in the shallow aquifer and the essential need for reducing abstraction in the deep confined aquifers. This research not only supports the sustainable groundwater management strategy in Beijing but also provides a valuable framework for other urban areas worldwide facing similar challenges of groundwater depletion.","","en","doctoral thesis","IHE Delft Institute for Water Education","978-90-73445-59-8","","","","","","","","","Water Resources","","",""
"uuid:e44fa728-4b95-4435-9a17-da29c3359418","http://resolver.tudelft.nl/uuid:e44fa728-4b95-4435-9a17-da29c3359418","Reuse of previously captured knowledge in current and future projects","Thimmapa, Pradeepthi (TU Delft Civil Engineering & Geosciences)","van Os, M. (mentor); Koolwijk, J.S.J. (graduation committee); Bakker, H.L.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Contemporary project-based organisations recognise the importance of leveraging past project knowledge for competitive advantage. By leveraging the lessons learned from previous and ongoing projects, organisations can benefit from managing learning within and across projects effectively. Despite these benefits, challenges persist in effectively reusing captured knowledge. This qualitative study addresses this gap by investigating knowledge reuse in project-based organisations, with a focus on social learning mechanisms. The results underline the pivotal role of collaboration and social interactions in facilitating tacit knowledge sharing and reuse, along with the significance of learning on the job.
The research identifies drivers, barriers, and guiding principles for promoting knowledge reuse, addressing barriers such as motivation, resistance to change, and knowledge silos. Recommendations include establishing comprehensive databases, fostering collaboration, and strengthening Communities of Practice aligned with organisational goals. Moreover, the study emphasises that true organisational learning primarily occurs through social interactions, advocating for a shift from 'learning from repositories' to 'learning through social means.' It underscores the role of organisational culture, particularly trust, in enhancing learning and knowledge reuse, promoting personal networks, communities of practice, and blame-free cultures. Lastly, guiding principles advocate for both top-down and bottom-up approaches to foster knowledge reuse across all organisational levels.","Knowledge Reuse; Social learning; Project-based learning; communities of practice (COP); Collaboration; Atlas.ti","en","master thesis","","","","","","","","","","","","Civil Engineering | Construction Management and Engineering","",""
"uuid:c5864f99-426b-4377-8eaf-244bb0f29bf4","http://resolver.tudelft.nl/uuid:c5864f99-426b-4377-8eaf-244bb0f29bf4","Re:/Dis:/Assembling Droixhe: Post-war Social Housing Urban Ground Transformation","Kirilov, Konstantin (TU Delft Architecture and the Built Environment)","Ronner, E.I. (mentor); Reinders, L.G.A.J. (graduation committee); Lafeber, J.W. (graduation committee); Stalker, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","The post-war architectural and urban design paradigm’s characteristic trait of spatial and functional determination limits the possibility for spatial adaptation and flexibility in urban spaces, struggling to face ever-steadily occurring social, economic, and climate challenges. In Droixhe - the largest post-war social housing ensemble in Liège, Belgium, the ineffective reach of previously executed housing requalification and increasing mismanagement overlook the urban public space on the housing blocks’ ground level, leading to its progressive deterioration and alienating fixed spatial ambience.
Drawing from the assemblage thinking theory in urban design and the notion of non-static built environments, the thesis project ‘Re:/Dis:/Assembling Droixhe’ incorporates architectural and urban design interventions within the ensemble’s urban ground level, allowing for ever-evolving compositions of elements with changing interrelationships, while challenging the pre-existing Modernist static built entities. Underlining the notion of “the incomplete”, the established design framework suggests the (re-)evaluation and upgrade of existing compositions through flexible building elements, which create the possibility to be critically reviewed and eventually recalibrated over time in response to occurring challenges. Applying a holistic multi-method approach, this design research aims to unveil the potential and challenges of urban transformation in static post-war urban environments as a point of departure to a more community-engaging and environmentally conscious architectural practice.
The rise of Artificial Intelligence (AI), from curatorial AI in YouTube to generative AI in ChatGPT, demonstrates both potential for progress and risks of harm. Adopting a Positive Design approach aimed at directly enhancing human wellbeing, this dissertation develops the concept of Positive AI. It explores the role of designers in steering AI innovation towards holistically supporting flourishing, not just optimizing profit or user engagement. Through human-centered methods, this research seeks to advance understanding and techniques for assessing and iteratively improving AI's impact on wellbeing.
Key questions address how wellbeing manifests in AI systems, how it can be measured, how to design interventions, and how to evaluate them. Outcomes include conceptual frameworks, case studies demonstrating approaches, proposed methods, and evaluations, aimed at laying a robust foundation for AI that fosters human flourishing. A cybernetics perspective organizes the challenges for designing AI for wellbeing, emphasizing the importance of feedback loops connecting assessments and actions.
A longitudinal case study at Delft University of Technology presents ""My Wellness Check,"" a cybernetic system for community wellbeing during COVID-19. The project, spanning two years and engaging 20,311 participants, demonstrates the application of cybernetic principles in a complex sociotechnical context. Building on these insights, a novel method is developed to systematically integrate wellbeing into AI design through distinct phases, from contextualizing wellbeing needs to continuously aligning AI behavior with wellbeing goals. The method's effectiveness is exemplified through diverse student projects, with expert evaluations providing evidence of its practicality and efficacy.
Finally, the research synthesizes insights into a set of recommendations, charting concrete next steps for researchers and practitioners across fields to further mature these nascent perspectives and capabilities towards Positive AI. Key recommendations include integrating human-centered design methods, balancing immediate desires with long-term wellbeing, contextualizing wellbeing through participatory processes, establishing multidimensional feedback loops, shifting from harm mitigation to actively cultivating flourishing, and embracing Positive AI as an ongoing process. Through multifaceted efforts spanning advocacy, policy, and community building, the Positive AI agenda can progressively guide innovation trajectories towards enhancing societal wellbeing. While further work is needed to fully realize its potential, this dissertation makes important strides in laying the groundwork for AI that actively prioritizes human flourishing through integrative, collaborative design.","design; artificial intelligence; wellbeing; cybernetics; positive psychology","en","doctoral thesis","","","","","","","","","","","Design Aesthetics","","",""
"uuid:b9cf52ab-06fa-40bf-882e-96a72d8e234d","http://resolver.tudelft.nl/uuid:b9cf52ab-06fa-40bf-882e-96a72d8e234d","Fingerprinting the Properties of WS2 Nanostructures using Advanced Transmission Electron Microscopy Techniques: From Growth to Characterization","van Heijst, S.E. (TU Delft QN/Conesa-Boj Lab)","Conesa Boj, S. (promotor); Kuipers, L. (promotor); Delft University of Technology (degree granting institution)","2024","class=""MsoNormal"">Two-dimensional (2D) layered materials have attracted the interest of the scientific community following the discovery of graphene and its extraordinary properties. Of particular interest is a class of materials called transition metal dichalcogenides (TMDs). The materials within this class were discovered to show similarly intriguing optical and electronic properties, when compared to graphene. Moreover, research indicated that these properties are also highly sensitive to the TMDs' underlying atomic structure. Gaining control over these structural properties would enable the tuning of the physical and chemical properties, and hence allow for the fabrication of novel TMD nanostructures with tailored functionalities. Driven by this potential, we strive to gain a comprehensive understanding of the relationship between the structural, chemical, and local electronic properties of nanostructures based on one such TMD material: tungsten disulfide (WS2). This in order to aid us in the exploitation of the tunability of these physical properties through the fabrication of novel WS2 nanostructures. …","Transition metal dichalcogenides (TMDs); Nanostructures; Chemical vapor deposition (CVD); Transmission electron microscopy (TEM); Electron energy-loss spectroscopy (EELS); Four-dimensional scanning transmission electron microscopy (4D-STEM); Electron microscope pixel array detector (EMPAD)","en","doctoral thesis","","978-94-6384-557-1","","","","","","","","","QN/Conesa-Boj Lab","","",""
"uuid:d46d5f09-9a3b-4887-a4b5-17690920cb1d","http://resolver.tudelft.nl/uuid:d46d5f09-9a3b-4887-a4b5-17690920cb1d","Non-Assembly Additive Manufacturing of Medical Devices","Lussenburg, K.M. (TU Delft Medical Instruments & Bio-Inspired Technology)","Breedveld, P. (promotor); Sakes, A. (copromotor); Delft University of Technology (degree granting institution)","2024","Additive manufacturing, or 3D printing, offers a new paradigm for the way functional products are designed, manufactured, and assembled. Its additive nature provides the ability to create complex-shaped parts, without an increase in production time or costs, which would be difficult to produce with conventional manufacturing. In addition, integration of different functions and materials allows for the production of completely functional assemblies or mechanisms that can be produced in a single production step, known as non-assembly additive manufacturing. These mechanisms are functional immediately after 3D printing, without requiring additional assembly steps. Non-assembly mechanisms have some advantages over traditional assembly-based mechanisms, as they reduce the processing time and costs, and allow for an increase in complexity....","non-assembly design; Additive manufacturing (AM); 3D printing; Design for manufacture and assembly; medical device; surgical instruments; miniaturization","en","doctoral thesis","","978-94-6496-092-1","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:b8954e95-15d9-430d-b026-71f4cf99ef23","http://resolver.tudelft.nl/uuid:b8954e95-15d9-430d-b026-71f4cf99ef23","On ice mechanics in ice-induced vibrations","Owen, C.C. (TU Delft Offshore Engineering)","Metrikine, A. (promotor); Hendrikse, H. (copromotor); Delft University of Technology (degree granting institution)","2024","The imminence of anthropogenic climate change has motivated a global energy transition towards sustainable power generation. Offshore wind—an important contributor to the energy transition—is expanding, not only in turbine size and number of installations, but also into regions with harsher environmental conditions. One of those conditions in places such as the Baltic Sea is drift ice. Offshore wind turbine support structures, with vertical sides at the waterline, must be designed to survive dynamic ice-structure interaction when ice fails in crushing against the structure. For a safe and efficient design of the support structure, dynamic ice-structure interaction resulting in ice-induced vibrations must be considered. Therefore, both an understanding of the problem and accurate modeling for the prediction of the development of ice-induced vibrations are required.
Significant progress has been made in recent years on the topic of ice-induced vibrations, and a numerical model for prediction of ice-induced vibrations has been developed based on the principles of velocity-dependent deformation and failure behavior of ice, and contact area variation between ice and structure during interaction. However, uncertainty remains regarding physical mechanisms within the ice which govern ice-induced vibrations. The ice mechanics involved in the development of ice-induced vibrations is therefore the main topic of this thesis.
The main objective was to investigate and identify the ice mechanics involved in the development of ice-induced vibrations, especially in the regime of frequency lock-in as historically defined. It was hypothesized that dynamic recrystallization played a relevant role in the ice mechanics involved in ice-induced vibrations. To test the hypothesis, ice mechanics experiments were performed at the ice laboratory specifically developed at Delft University of Technology for this purpose.
To identify grain-scale mechanisms in ice, such as dynamic recrystallization, a method was devised to elucidate ice thin section textures and (quarter) fabrics by means of crossed-polarized transmitted light and interference coloration of ice. An attempt was made to apply the method to the laboratory experiments which applied compressive loading to the edge of a thin freshwater columnar-grained ice plate, laterally confined by glass plates. Crossed-polarized transmitted light was shone through the glass plates to observe the grain structure of the ice during cyclic compression with a haversine velocity waveform. The loading and confinement scenario was intended to reproduce a vertical section of the ice edge during frequency lock-in vibrations. The experimental design demonstrated that the grain-scale mechanics of dynamic recrystallization did not obviously contribute to the peak load-velocity relation associated with frequency lock-in vibrations. As expected, fracture initiated on the grain scale was responsible for load drops. But, more interestingly, stress relaxation during periods of low relative velocity between ice and structure occurred rapidly. Following the stress relaxation, when velocity increased, the peak load was higher than previous brittle peak loads. The results indicated that the mechanisms involved in the stress relaxation were occurring on a scale smaller than the grain size. A loading path dependency was also observed with respect to the peak load-velocity relation.
Ice penetration experiments at the Aalto Ice and Wave Tank in ethanol-doped cold model ice were performed with a rigid structure, controlled oscillation, and a single-degree-of-freedom structure, and comparison of results showed that the peak global ice loads depended on the amount of time spent at low relative velocities where an ice strengthening effect developed. This has implications for the so-called velocity effect and compliance effect in design of structures subject to dynamic ice-structure interaction.
Overall, the load signals from the ice mechanics experiments on freshwater ice resembled the load signals obtained from the controlled-oscillation experiments from the model-scale ice tank tests. The qualitatively similar velocity and resulting load patterns give confidence in the idea that the mechanisms involved in both types of experiments were similar, even for different ice types and loading scenarios.
These similar results demonstrate a link in the ice mechanics across different ice types and loading scenarios, which may be explained with further research on path-dependent constitutive ice behavior, and with scrutiny regarding ice dislocation and grain boundary mechanics. Suggestions for future research are proposed, including the testing of strain rate-varying uniaxial compression of ice and ice penetration experiments with haversine velocity waveforms.","dynamic ice-structure interaction; ice-induced vibrations; frequency lock-in; c-axis; interference coloration; ice microstructure; ice fabric; ice texture; image processing; birefringence; grain boundary; controlled oscillation; ice failure length; anelasticity; ice crushing; model tests; compliance effect; velocity effect","en","doctoral thesis","","978-94-6366-819-4","","","","","","2024-04-08","","","Offshore Engineering","","",""
"uuid:a77057c6-c796-4310-b8a9-3f0e78ea9648","http://resolver.tudelft.nl/uuid:a77057c6-c796-4310-b8a9-3f0e78ea9648","Productive inclusion of smallholders in the Brazilian biodiesel value chain: a path of challenges and opportunities","Solidario de Souza Benatti, G. (TU Delft BT/Biotechnology and Society)","Osseweijer, P. (promotor); Asveld, L. (promotor); Buainain, Antonio Marcio (promotor)","2024","This doctoral dissertation delves into the complex challenge of smallholder productive inclusion within the biodiesel value chain in Brazil. The focus is on the National Policy for Biodiesel Production and Use (PNPB) and its instrument to promote smallholder inclusion: the Social Biofuel Seal (SBS). Productive inclusion of smallholders in value chains can be a strategy for poverty alleviation and resilient and inclusive development. However, the concept of productive inclusion is not clearly defined in the literature, and it is not yet a priority in most policies aimed at the transition to a bioeconomy. One of the outputs of this thesis is to define the concept in a way that suits the discussions regarding inclusive biobased value chains.
The research poses the question of ""how can governance enhance smallholder inclusion in biobased value chains in Brazil, emphasizing the promotion of stable employment, income generation, and fair economic risk distribution among stakeholders?"".
The experience of PNPB illustrates that managing the tension between immediate needs and long-term goals is a significant challenge. Although PNPB and SBS have made strides in promoting inclusive biobased value chains, achieving the anticipated results is complicated due to the complexity of productive inclusion, the Brazilian context, and the policies themselves. The study underscores the importance of addressing both technological advancement and economic viability, as well as the impacts on local communities, social structures, and cultural dynamics, to prevent adverse outcomes like exclusion. It also highlights the need to confront historical injustices and power imbalances to achieve smallholder productive inclusion. State capability development is crucial for supporting smallholder productive inclusion goals. PNPB's experience showcases the importance of institutional, political, regulatory, and coordination capabilities. The study argues for adaptive and participative governance arrangements to progress the energy transition while prioritizing inclusion as a long-term goal.","inclusion; smallholder farmers; biodiesel; public policy; Bioeconomy; Brazil","en","doctoral thesis","","978-94-6384-574-8","","","","","","","","","BT/Biotechnology and Society","","",""
"uuid:a0f812bd-ca0c-4bca-a804-efbf06e6e07c","http://resolver.tudelft.nl/uuid:a0f812bd-ca0c-4bca-a804-efbf06e6e07c","Spinful Andreev States in Superconducting Circuits","Wesdorp, J.J. (TU Delft QRD/Kouwenhoven Lab)","Kouwenhoven, Leo P. (promotor); Andersen, C.K. (copromotor); Delft University of Technology (degree granting institution)","2024","The growing understanding of the physics of superconductor-semiconductor nanostruc- tures is a key driver for the development of emerging quantum technologies. The elemen- tary excitations of these hybrid nanostructures are Andreev bound states. To further our knowledge about their intricate physics, new tools must be used to study them. This thesis describes the use of magnetic-field compatible superconducting circuits to study and ma- nipulate Andreev bound states and their spin in hybrid superconducting-semiconducting nanowire Josephson junctions.
First, we provide an introduction to the physical models describing Andreev bound states in superconducting circuits and the general methodology used for the circuit design, device fabrication and experimental setups in the experiments of this work.
We then move on to an initial set of two experiments in Chapters 4 and 5, where we inductively shunt a superconducting resonator with a nanowire-based radio-frequency su- perconducting quantum interference device (rf-SQUID). This allows us to study Andreev bound states in InAs/Al nanowire Josephson junctions using circuit quantum electrody- namics techniques under various external conditions.
In Chapter 4 we use pulsed detection of Andreev bound state parity to demonstrate par- ity selective spectroscopy. The main result of this Chapter was the discovery of microwave- induced parity polarization, that allows one to set the bound state parity in-situ using microwave pulses. We then study the evolution of the microwave spectrum of Andreev bound states in a magnetic field in Chapter 5. Here we find a multitude of phenomena that arise because of the rich interplay between spin-orbit coupling, the Zeeman effect, super- conductivity, and electron-electron interactions. We observe evidence of spin-polarizing microwave transitions, the anomalous Josephson effect, and transitions involving triplet Andreev spins.
In Chapter 6 we explore an alternative material and junction fabrication method in combination with the same circuitry. Specifically, we excite Andreev bound states in InS- b/Al Josephson junctions defined by shadow-wall lithography. We observe low density, high-transparency Andreev bound states in a range of devices and reproduce the directly spin-polarizing microwave transition observed in Chapter 5. The results of this Chap- ter demonstrate the viability of combining hybrid circuit quantum electrodynamics with advanced material combinations and fabrication geometries.
In the final experiment, Chapter 7, we move back to InAs/Al based junctions. This Chapter uses previous results from Chapter 5 and works demonstrating the use of a single superconducting spin as a quantum bit, as a stepping stone. Here, we embed two super- conducting spin qubits in a single SQUID and demonstrate strong longitudinal coupling between them over a distance much larger than their wavelengths.
The results and methods developed in this dissertation pave the way for continued ex- ploration of the intricating physics of superconducting spins and demonstrate early steps towards their use as a new platform for quantum computing.","Andreev bound states; Josephson effect; Andreev spin qubits; Superconducting spin qubits; hybrid circuits; circuit-QED; superconductivity","en","doctoral thesis","","978-94-6473-472-0","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:079a4a73-1445-44f9-ac87-a0bc312b71ad","http://resolver.tudelft.nl/uuid:079a4a73-1445-44f9-ac87-a0bc312b71ad","On Color and Symmetries for Data Efficient Deep Learning","Lengyel, A. (TU Delft Pattern Recognition and Bioinformatics)","van Gemert, J.C. (promotor); Reinders, M.J.T. (promotor); Delft University of Technology (degree granting institution)","2024","Computer vision algorithms are getting more advanced by the day and slowly approach human-like capabilities, such as detecting objects in cluttered scenes and recognizing facial expressions. Yet, computers learn to perform these tasks very differently from humans. Where humans can generalize between different lighting conditions or geometric orientations with ease, computers require vast amounts of training data to adapt from day to night images, or even to recognize a cat hanging upside-down. This requires additional data, annotations and compute power, increasing the development costs of useful computer vision models. This thesis is therefore concerned with reducing the data and compute hunger of computer vision algorithms by incorporating prior knowledge into the model architecture. Knowledge that is built in no longer needs to be learned from data.
This thesis considers various knowledge priors. To improve the robustness of deep learning models to changes in illumination, we make use of color invariant representations derived from physics-based reflection models. We find that a color invariant input layer effectively normalizes the feature map activations throughout the entire network, thereby reducing the distribution shift that normally occurs between day and night images.
Equivariance has proven to be a useful network property for improving data efficiency. We introduce the color equivariant convolution, where spatial features are explicitly shared between different colors. This improves generalization to out-of-distribution colors, and therefore reduces the amount of required training data.
We subsequently investigate Group Equivariant Convolutions (GConvs). First, we discover that GConv filters learn redundant symmetries, which can be hard-coded using separable convolutions. This preserves equivariance to rotation and mirroring, and improves data and compute efficiency. We also explore the notion of approximate equivariance in GConvs. Subsampling is known to introduce equivariance errors in regular convolutional layers, and we find that it similarly breaks exact equivariance for rotation and mirroring. This turns out to be a double-edged sword: while it improves performance on in-distribution data, at the same time it negatively affects out-of-distribution generalization. Finally, we show that exact equivariance can be restored by choosing an appropriate input size.
This thesis aims to provide a step forward in the adoption of invariant and equivariant architectures to improve data and compute efficiency in deep learning.","computer vision; visual inductive priors; data efficiency; equivariance; invariance; color","en","doctoral thesis","","978-94-6366-854-5","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:6b1e6a9c-e014-4092-bbd6-a35cce0503a1","http://resolver.tudelft.nl/uuid:6b1e6a9c-e014-4092-bbd6-a35cce0503a1","Structure Guided Directed Evolution of Enzymes","Hüppi, S.N. (TU Delft BT/Biocatalysis)","Hollmann, F. (promotor); Delft University of Technology (degree granting institution)","2024","Our ability to tailor enzymatic properties is a critical factor for biocatalyst application in the industrial sector. Although many wild-type enzymes have been found capable of promiscuously catalysing desired anthropogenic reactions, their activity and selectivity for non-natural transformations is often poor. Consequently, it is crucial to optimise enzymes such that they can be effectively integrated into industrial processes. Notable added advantages in this context are that enzymes are considered 'green' catalysts - enhancing the perceived value of products in today's environmentally-conscious society – and that biocatalysts can carry out intricate chemistries with exceptional regio- and stereoselectivity, complementing traditional organic synthesis.","Biocatalysis; Enzymes","en","doctoral thesis","","","","","","","","2024-04-24","","","BT/Biocatalysis","","",""
"uuid:dc575434-78fd-475d-81ed-f2a6a6d46845","http://resolver.tudelft.nl/uuid:dc575434-78fd-475d-81ed-f2a6a6d46845","Integrated Electrical Steady-State Power Flow Simulations on Transmission and Distribution Networks","Kootte, M.E. (TU Delft Mathematical Physics)","Vuik, Cornelis (promotor); van Gijzen, M.B. (promotor); Delft University of Technology (degree granting institution)","2024","Integrated electrical power flow simulations are concerned with solving the steady-state load flow problem on integrated transmission and distribution electricity networks. We have developed a framework to run these simulations efficiently, whilst keeping in mind the differences between these network types and accommodating the practical considerations of system operators. We need such a framework to analyse the interaction that these systems might have as a result of the energy transition.
To develop a framework to run integrated power flow simulations, we have worked in two stages. Firstly, we have studied how we can model an integrated network. We have found two ways of modelling an integrated network: using a homogeneous configuration in which both networks are modelled using three phases and using a hybrid network configuration in which both networks keep their original configuration but in which the coupling substation takes care of the phase dimension mismatch between the two sides. Next to that, we have found two ways of solving an integrated system: either by coupling them into one system and solving that as a whole (we call this the unified approach) or by keeping two separate systems and iterating between these networks (we call this the Manager‐Fellow Splitting (MFS) method).
We have concluded that the unified methods are generally faster than MFS methods and that a hybrid network configuration leads to faster results, making the interconnected method the most efficient.
In the second stage, we have focused on the efficiency of these simulations. During every Newton‐Raphson iteration in power flow simulations, a linear system is solved. We have therefore studied several Krylov subspace and preconditioning techniques that can solve this linear system efficiently. We have applied Krylov and preconditioning combinations to integrated network simulations to check again the performances of the simulations on large test cases . During this stage, we applied them to networks up to a size of 800,000 buses as we were interested in efficient scaling of the methods that were originally the object of study.
In the second stage, we saw that the MFS methods were performing better than unified methods. Furthermore, preconditioned Krylov subspace methods had a similar performance to direct methods. t is difficult to judge why this happened. A reason could be that the library in which we performed these simulations, PETSc, is optimised for parallel computations in which multiple smaller blocks are solved at the same time whilst we were doing only sequential computations.
Finally, we have striven to incorporate operational convenience for Transmission and Distribution System Operators (TSOs and DSOs) during the development of this integration framework, by considering their computational and privacy concerns. The way that this framework is built, can take away some of their concerns.
To summarise, we have created an open‐source framework to run efficient steady-state power flow simulations on integrated transmission and distribution networks. This framework is tested on simplified test cases but shows potential for large system simulations. Moreover, it takes into account the considerations of system operators and can be utilised in other applications besides integrated analysis.","Power Flow; Numerical analysis; Newton-Krylov methods; Iterative methods","en","doctoral thesis","","978-94-6483-990-6","","","","","","","","","Mathematical Physics","","",""
"uuid:2ee2a492-6588-46db-aa6a-7056fd37fd24","http://resolver.tudelft.nl/uuid:2ee2a492-6588-46db-aa6a-7056fd37fd24","Gate-tunable kinetic inductances for superconducting circuits","Splitthoff, L.J. (TU Delft QRD/Andersen Lab)","Kouwenhoven, Leo P. (promotor); Andersen, C.K. (copromotor); Delft University of Technology (degree granting institution)","2024","Superconducting circuits in cryogenic environments form an excellent material platform for the realization and study of quantum systems.
In this thesis, we continue the exploration of novel types of circuit elements which expand the circuit quantum electrodynamics toolbox to enable exotic, and potentially better circuit implementations. To this end, we combine the study of condensed matter systems and circuit quantum electrodynamics in what is called hybrid cQED experiments to arrive at the implementation of gate-tunable kinetic inductances for superconducting circuits. This discovery shed new light on the physics of gate-tunable kinetic inductances and enabled the observation of emergent phenomena in gate-tunable metamaterials, in particular the phase transition in a bosonic Su-Schrieffer-Heeger chain. Moreover, as gate-tunable kinetic inductances became available we realized tunable resonators and parametric amplifiers for enhanced control and readout of superconducting circuits.","Gate-tunable superconducting circuits; Resonator-based parametric amplifiers; Topological metamaterials; Proximitized nanowires","en","doctoral thesis","","978-94-6384-540-3","","","","","","2024-04-15","","","QRD/Andersen Lab","","",""
"uuid:b2e0711a-e0c2-41b3-ae0a-c8e407efb2ac","http://resolver.tudelft.nl/uuid:b2e0711a-e0c2-41b3-ae0a-c8e407efb2ac","Electrostatic Lens System Design and Optimization Using Evolutionary Algorithms","Hesam Mahmoudi Nezhad, N. (TU Delft ImPhys/Hagen group)","Kruit, P. (promotor); Hagen, C.W. (promotor); Ghaffarian Niasar, M. (copromotor); Delft University of Technology (degree granting institution)","2024","The design of electrostatic charged particle lenses involves changing many geometrical parameters of the lens electrodes as well as changing the voltages at each lens electrodes. The objective of the design is often to get the electrons passing through the lens system to be focused at a specific point and to minimize the aberrations of the lens. To make such a design is a laborious task for electron optical lens designers. A fully-automated optimization routine to relieve the laborious manual design of charged particle lens systems has been demanded for years, however, to achieve this outcome while many free optimization parameters are involved in the lens system design is quite a challenge. This is mainly due to calculations of the lens electric potential which are in general carried out with very time-consuming techniques that require meshing of the lens space. Currently it is not difficult to find the electron-optical software to conduct accurate field calculations such as EOD, GPT, CPO, Simion, etc., that can be used in an optimization loop. However, it can take months to get the results. For instance, the design of even a simple system using COMSOL takes such a long computational time that the designer might not have the patience to wait for the result (assuming the computational memory allows them to do so). Therefore, although some charged particle optics design programs exist which could change a few geometrical parameters of the lenses or the voltages (EOD, GPT, CPO, Simion, etc.), a fully-automated optimization routine which could make a design where all geometries and voltages of the lenses could be varied in a feasible time did not exist. A first attempt (SOEM) was made more than 30 years ago, but it still had too many limitations to be widely used. The main objective of this thesis therefore was to find a technique which would enable electron optical designers to tackle this problem...","","en","doctoral thesis","","978-94-6496-106-5","","","","","","","","","ImPhys/Hagen group","","",""
"uuid:92ebf293-d057-4ab3-b11a-ba2204f377e8","http://resolver.tudelft.nl/uuid:92ebf293-d057-4ab3-b11a-ba2204f377e8","Ensemble data assimilation methods for estimating fault slip and future earthquake occurrences","Diab Montero, H.A. (TU Delft Reservoir Engineering)","Jansen, J.D. (promotor); Vossepoel, F.C. (copromotor); Delft University of Technology (degree granting institution)","2024","In this dissertation, I explore ensemble data assimilation methods to enhance our capability to forecast earthquakes and slow slip events, focusing on the critical challenge posed by limited information on the current stress state of faults.
At the outset, the research acknowledges the inherent limitations in our current understanding of fault stress states. These limitations significantly hinder our ability to forecast seismic events accurately. The study proposes utilizing ensemble data assimilation techniques as a robust solution. Central to this dissertation, these methods enable estimating the fault’s state by integrating information from physics-based models with observational data. Importantly, this approach considers the uncertainties inherent in both the models and the data, offering a more reliable framework for forecasting. The dissertation emphasizes that probabilistic forecasts represent the highest achievable goal in earthquake forecasting. However, it also recognizes the challenges that arise from limited information on critical aspects such as stress, strength, and governing parameters of seismogenic sources. These limitations can significantly impede the accuracy of forecasts.
Throughout the dissertation, I systematically examine how ensemble data assimilation can be effectively implemented to improve earthquake forecasting. This involves exploring current fieldmeasurement techniques and the data quality they produce. The study demonstrates how ensemble data assimilation can bridge the gap between empirical observations and theoretical understanding by carefully analyzing and integrating this data with advanced theoretical models.
A core component of the research is a critical evaluation of various data assimilation techniques, mainly focusing on their ability to enhance forecasting accuracy in the context of limited information on fault stress states.
Furthermore, I explore practical applications of these techniques using 1D and 2D models. This includes investigating how data assimilation can improve the forecasting of earthquake occurrences and the inherent challenges in making such estimations.
The dissertation culminates in a forward-looking discussion on the future of earthquake forecasting. It emphasizes the role of ensemble data assimilation methods in overcoming the current limitations of stress state information and proposes ways for more informed seismic forecasts.","Data assimilation; Inverse theory; Numerical modelling; Probabilistic forecasting; Earthquake interaction, forecasting, and prediction; Earthquake dynamics; Seismic cycle; Ensemble Kalman Filter","en","doctoral thesis","","978-94-6384-568-7","","","","","","","","","Reservoir Engineering","","",""
"uuid:b335a2d8-6cdb-4f7d-b5d3-5f26cdfe5fda","http://resolver.tudelft.nl/uuid:b335a2d8-6cdb-4f7d-b5d3-5f26cdfe5fda","ReAIC: Reactive Active Inference Control for Enhanced Performance of Robotic Manipulators","Dawe, Alon (TU Delft Mechanical Engineering; TU Delft Cognitive Robotics)","Babuska, R. (mentor); Wisse, M. (graduation committee); Franzese, G. (graduation committee); van Hoof, C.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","","Free-energy principle; Active Inference; Active inference control; Adaptive control; robot control; AIC; ReAIC","en","master thesis","","","","","","https://github.com/AlonDawe/interbotix_aic_control Repository link GitHub Repository","","2026-04-30","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:1375be15-ea9c-4229-a3a2-819c597cf2f4","http://resolver.tudelft.nl/uuid:1375be15-ea9c-4229-a3a2-819c597cf2f4","Computational Techniques Toward 1 nm Super-resolution Microscopy","Wang, W. (TU Delft ImPhys/Computational Imaging; TU Delft ImPhys/Rieger group)","Rieger, B. (promotor); Stallinga, S. (promotor); Delft University of Technology (degree granting institution)","2024","This thesis explores advanced computational techniques in super-resolution microscopy (SRM), with the primary goal of pushing the limits of achievable resolution towards the 1 nm scale. It includes developments in particle fusion algorithms, data analysis of complex biological structures, and exploration of the impact of molecular dipole orientation on MINFLUX localization accuracy and precision.
In the first part, we present a novel fast particle fusion method tailored to single molecule localization microscopy (SMLM). This method first registers particles based on Joint Registration of Multiple Point Clouds (JRMPC) and then classifies and reconnects misaligned locally optimally clustered sets of particles. This approach significantly reduces computational cost compared to earlier template free methods in particular for a large number of particles.. This advancement enables more detailed and accurate reconstructions of super-particles, enhancing the capabilities of SMLM.
The second part of the dissertation deals with a data analysis of nuclear pore complexes (NPCs) reconstructed by the earlier developed particle fusion technique. By fusing thousands of NPCs labeled at nucleoporin Nup96 and analyzing the high-resolution reconstructions, we reveal intricate details of the NPC structure, in particular the unit structure of Nup96. This analysis showcases the potential of SRM in combination with advanced data analysis to contribute to structural biology on the length scale below 10 nm.
The third part focuses on the influence of the dipole orientation on the localization accuracy and precision of MINFLUX. We simulate the imaging process with a physically realistic vector diffraction Point Spread Function (PSF) model and then localize the emitters based on the simplified Gaussian doughnut PSF model used in MINFLUX so far. Our study, including dipoles with free and fixed orientations and key simulation parameters, reveals the need for more refined modeling to overcome the bias, especially for fixed dipole orientations and background fluorescence. This investigation helps to understand the limitations of MINFLUX in its current form and paves the way for future improvements of the technique.
Finally, we discuss potential future directions for improving SRM techniques. These include refining the fast particle fusion method by incorporating localization uncertainties and prior knowledge, optimizing experimental parameters in MINFLUX, and developing advanced localization strategies to improve accuracy and efficiency. By addressing these future challenges, SRM technologies can move closer to the goal of 1 nm resolution in super-resolution imaging.","single-molecule localization microscopy; physical optics modeling; biological structure analysis","en","doctoral thesis","","97894647304652","","","","","","2024-04-24","","","ImPhys/Computational Imaging","","",""
"uuid:b06f8ece-26c2-4244-90d5-7f91f951d9c5","http://resolver.tudelft.nl/uuid:b06f8ece-26c2-4244-90d5-7f91f951d9c5","Horizontal Tail and Aileron Sizing for Distributed Electric Propulsion Aircraft","Dundulis, Tomas (TU Delft Aerospace Engineering)","de Vries, R. (mentor); Vos, Roelof (graduation committee); Hoogreef, M.F.M. (graduation committee); van Kampen, E. (graduation committee); Delft University of Technology (degree granting institution)","2024","The concept of Distributed Electric Propulsion (DEP) aircraft holds great promise in achieving the goals outlined in Flightpath 2050. This involves utilizing electricity to power propellers and enhancing overall flight performance through interactions between the wings and propellers. This thesis investigates the stability and control aspects of DEP aircraft compared to conventional aircraft. A tool is proposed to estimate the minimum horizontal tail and aileron size for different configurations, considering propeller effects. Analyzing three configurations (turboprop excluding propeller effects, turboprop including propeller effects, and DEP including propeller effects), propellers are found to destabilize the aircraft but enhance take-off rotation and provide additional damping during roll. The DEP aircraft exhibits a 19% smaller normalized horizontal tail size than the turboprop (with propeller effects), attributed to lower propeller destabilizing moments and a shorter fuselage. Despite a lower roll requirement, the DEP aircraft needs the same normalized aileron size due to larger rolling moment of inertia. A sensitivity analysis suggests a T-Tail is optimal for DEP aircraft stability, and adjusting battery placement and reserve fuel improves overall performance.","Distributed electric propulsion; Stability and control; Horizontal tail; Aileron; Elevator; Propeller effects; Moment of inertia; Design; Sizing","en","master thesis","","","","","","","","2025-04-23","","","","Aerospace Engineering","",""
"uuid:21452629-b583-44ad-87b7-47a3bdb1b99a","http://resolver.tudelft.nl/uuid:21452629-b583-44ad-87b7-47a3bdb1b99a","Water sector in the face of a societal collapse: How a societal collapse can cause cascading failures and challenge the provision of drinking water","van Kleef, Emma (TU Delft Technology, Policy and Management)","Nikolic, I. (graduation committee); Kammouh, O. (mentor); Pesch, U. (graduation committee); Delft University of Technology (degree granting institution)","2024","This research examines the resilience of the water sector after a societal collapse, defined by a significant loss of societal complexity. Through Exploratory Modeling and Analysis, this research evaluates how interconnected infrastructures respond to cascading failures caused by disruptions resulting from a societal collapse. The investigation centers on the interdependencies within the water sector, crucial for its function to abstract, treat, store, and distribute water. The model makes use of disruption curves affecting a network of interdependent components to simulate cascading failures, factoring in variables such as population change and contamination rates.
The research makes use of expert interviews and economic Input-Output tables to devise the dependency matrix, finding that accurate representation of dependencies is critical for meaningful results. The model allows for adaptation strategies, specific to the dependencies of a sector, which demonstrates potential improvements in water sector performance and suggests that adaptive methods may be more effective and less costly than redundancies.
While the model simplifies complex interactions and cannot fully encapsulate the breadth of societal collapse effects, it sheds light on the importance of dynamic dependencies and offers a framework for future studies. These could include integrating more intricate domain-specific models to refine the responses of sectors to disruptions and reduced input. The findings highlight the significance of adaptation as a means to enhance the water sector's resilience.","Societal collapse; Water sector; Infrastructure resilience; Critical infrastructures; Drinking water","en","master thesis","","","","","","","","","","","","Engineering and Policy Analysis","",""
"uuid:33283954-fd1d-40c9-a6bf-7bd020350bbe","http://resolver.tudelft.nl/uuid:33283954-fd1d-40c9-a6bf-7bd020350bbe","Context-specific value inference via hybrid intelligence","Liscio, E. (TU Delft Interactive Intelligence)","Jonker, C.M. (promotor); Murukannaiah, P.K. (copromotor); Delft University of Technology (degree granting institution)","2024","Human values are the abstract motivations that drive our opinions and actions. AI agents ought to align their behavior with our value preferences (the relative importance we ascribe to different values) to co-exist with us in our society. However, value preferences differ across individuals and are dependent on context. To reflect diversity in society and to align with contextual value preferences, AI agents must be able to discern the value preferences of the relevant individuals by interacting with them. We refer to this as the value inference challenge, which is the focus of this thesis. Value inference entails several challenges and the related work on value inference is scattered across different AI subfields. We present a comprehensive overview of the value inference challenge by breaking it down into three distinct steps and showing the interconnections among these steps.","Values; Natural Language Processing; Morality; Ethics; Explainable AI; Active Learning; Hybrid Intelligence","en","doctoral thesis","","978-94-6366-840-8","","","","","","","","","Interactive Intelligence","","",""
"uuid:697b44bb-0bf5-4e9a-878c-626cdb831bf3","http://resolver.tudelft.nl/uuid:697b44bb-0bf5-4e9a-878c-626cdb831bf3","Green Health: Examining the role of green space characteristics and their proximity in green space health pathways","Cardinali, M. (TU Delft Heritage & Architecture)","Pottgiesser, U. (promotor); van Timmeren, A. (promotor); Beenackers, Mariëlle A. (copromotor); Delft University of Technology (degree granting institution)","2024","This doctoral thesis critically examines green space characteristics and their proximity to residents in their ability to help reduce the global disease burden of non-communicable diseases. By dissecting three pivotal pathways of theorized green space health effects through increased physical activity, increased social cohesion, and reduced air pollution, the thesis aims to provide new insights into which green space characteristics drive these relationships and in which distance they occur. To achieve these aims, this thesis develops reporting guidelines for the research field, a QGIS script for automatization of green space indicator development and uses two complementary sources for data collection. It builds on the self-reported data on physical activity, social cohesion, air pollution, health and mental health from the URBiNAT project and its case studies in the four European satellite neighbourhoods Nantes-Nord (France), Porto-Campanhã (Portugal), Sofia-Nadezhda (Bulgaria), and Høje-Taastrup (Denmark) and complements it with a rigorous spatial analysis. This enabled a rigorous sensitivity analysis based on up to 135 structural equation models per pathway. The results of this doctoral research revealed distinct green space characteristics and proximities that drive each pathway, including thresholds where these associations disappear or even change direction. It concludes that interconnected, multi-use green corridors are more beneficial than isolated patches for all analysed health pathways, challenging current municipal green space strategies to shift focus from mere ratios to green mobility infrastructures. Although rooted primarily in European contexts and of a cross-sectional nature, the doctoral research provides new evidence for urban planning and public health. It emphasizes the practical implications of how to design green spaces to address health concerns. The results not only resonate with the WHO's Urban Health Research Agenda but also provide tangible recommendations for a healthier human habitat.","green space; greenness; health; well-being; mediation","en","doctoral thesis","A+BE | Architecture and the Built Environment","978-94-6366-849-1","","","","","","","","","Heritage & Architecture","","",""
"uuid:c8b86311-fe3d-440e-9983-4e6e4f1dfb67","http://resolver.tudelft.nl/uuid:c8b86311-fe3d-440e-9983-4e6e4f1dfb67","Big data in digital product innovation: Identifying the antecedents and consequences of using big data in digital product innovation – a multiple case study","Qiu, Y. (TU Delft Responsible Marketing and Consumer Behavior)","Hultink, H.J. (promotor); Cankurtaran, P. (copromotor); Delft University of Technology (degree granting institution)","2024","Innovation is critical in driving economic growth. It fosters new products and services to move the economy forward. On the other hand, innovation requires new technologies to thrive. One such technology that has revolutionised various industries is big data. By harnessing big data, businesses can unlock valuable insights to enhance decision-making processes and ultimately encourage innovation across sectors. While big data holds the potential to drive innovation and economic growth, managing big data-enabled digital product innovation projects is challenging. Organisations need the resources, knowledge, and skills to manage these projects. In addition, companies should also be aware of the privacy and security risks associated with these big data innovation projects. Considering all the many factors influencing big data innovation projects, it is necessary to understand how they impact these projects in order to manage them well. This doctoral project answers the main research question: How do companies develop big data analytics capabilities in digital product innovation? This doctoral research identifies the different factors that influence big data innovation projects and reveals the mechanisms behind how these factors influence each other and affect digital product innovation. This research contains a multiple-case study with four cases to explore the answers to the research questions. The case studies analysed four new digital service development projects from four big companies operating in different industries (i.e. transportation, internet, navigation, and cybersecurity) in the past five years. In these cases, big data from various sources are used as input for machine learning and statistical models to enable digital product innovation. For collecting research data for this study, the semi-structured interview protocol was used, focusing on the process of using big data in innovation projects, the challenges and factors that affect this process, and its consequences. This study’s findings highlight the mechanism of how antecedents influence big data analytics capabilities (BDAC) and subsequently impact innovation performance. The study applies the resource-based view (RBV) and dynamic capabilities view as theoretical frameworks to clarify the mechanism behind enhancing innovation performance. It investigates the antecedents of BDAC constructs, explores the interactions among these constructs, and evaluates their effects on innovation performance. This research enriches the existing literature by revealing how BDAC constructs promote their development, unveiling the dynamics within BDAC, and emphasising the vital role of data variety. Furthermore, it extends the literature by uncovering novel connections between dynamic capabilities and BDAC and between environmental uncertainty and BDAC, broadening the scope of environmental uncertainty and examining the effects of BDAC constructs on innovation performance. For practitioners, this research suggests that innovation performance can be ultimately improved by enhancing data variety and establishing supportive internal and external environments for BDAC.","Big Data; Digital Product Innovation; Case Study","en","doctoral thesis","","978-94-6384-562-5","","","","","","","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:1e9082db-02d5-44d6-8c3e-c08932162d65","http://resolver.tudelft.nl/uuid:1e9082db-02d5-44d6-8c3e-c08932162d65","Resource management in wireless networks","Raftopoulou, M. (TU Delft Network Architectures and Services)","Van Mieghem, P.F.A. (promotor); Litjens, R. (copromotor); Delft University of Technology (degree granting institution)","2024","Following the trend of previous years, the number of devices, and hence the traffic in cellular networks is increasing. Moreover, new applications with stringent requirements are envisioned. Examples of such applications include collaborative learning and coverage extension with drones. To accommodate the traffic with its respective Quality of Service (QoS) requirements and to support new challenging applications in the Radio Access Network (RAN), we need to develop new algorithms and tools for efficient resource management. In this dissertation, resource management in the RAN is considered in three distinct areas.
In Chapter 2 we provide an introduction to the key concepts, which establish the technological context of the following chapters. The first part of this dissertation focuses on serving traffic with diverse requirements in the context of 5G networks. In 5G, RAN slicing has been introduced, to support services with diverse QoS requirements in the same network infrastructure. Moreover, RAN slicing allows the Mobile Network Operators (MNOs) to configure customer-specific slices. In Chapter 3, we assess RAN slicing in terms of the traffic handling capacity for an Industry 4.0-inspired scenario. For the assessment, we compare a network with isolated slices and a non-sliced network. Extensive simulations show that the non-sliced network can serve more traffic than the sliced network while satisfying the same class-specific QoS requirements. Considering that RAN slicing will be adopted by the MNOs, this result highlights that additional radio resource management mechanisms are needed when RAN slicing is configured. To that end, in Chapter 4 we evaluate RAN slicing in combination with allowing slices to use idle resources of other slices, in a realistic smart city environment. The results show that idle resource sharing significantly improves the traffic performance. However, it is not until RAN slicing is further combined with other technology features, i.e. flexible numerology and mini-slots that it provides better traffic performance than non-sliced networks.
The second part of this dissertation focuses on the application of collaborative learning, and more specifically on Federated Learning (FL) in resource-constrained wireless networks. In Chapter 5, we characterise agents by their importance in the learning process and the resource efficiency of their wireless channel. Then, we provide a general agent selection framework to indicate which agents should participate in the learning process. Extensive simulations in various scenarios verify the potential of the proposed framework. Additionally, it is revealed that in scenarios where agents have small data sets or the latency requirement is stringent, it is more beneficial to perform pure learning-based agent selection. In Chapter 6 we extend the previously proposed framework to perform joint agent selection and resource allocation. We describe the problem in resource-constrained vehicular wireless networks with Multi-User Multiple Input Multiple Output (MU-MIMO) capable base stations. To approximate the optimal solution of the problem, we propose the Vehicle-Beam-Iterative (VBI) algorithm. Then, we evaluate the VBI algorithm in scenarios related to vehicular communications. The results show that in scenarios where the vehicles have the same data set sizes, the application-specific accuracy targets are achieved faster than in scenarios where the data set sizes are different. Additionally, it is shown that MU-MIMO improves the convergence time of the global FL model.
In the third part of this dissertation, the deployment of a drone swarm is addressed. In Chapter 7 we study the link density is Random Geometric Graphs (RGGs). Specifically, we very accurately approximate the link density in any two- and three-dimensional rectangular spaces with the Fréchet distribution. Then, we express the minimum number of nodes needed to ensure network connectivity in terms of the link density. Finally, we model a drone swarm with a RGG and we estimate the required size of the swarm such that communication among all drones can be ensured.
The conclusions of this dissertation and the directions for future work are presented in Chapter 8.
Advanced convex economic model predictive control (CEMPC) methods have garnered attention lately in the wind turbine control community. Such techniques possess several advantages apart from those inherent in being subsets of the model predictive control (MPC) family. First, it is capable of accounting for multiple economic objectives for wind turbines, such as power production optimization, fatigue load reduction, and excessive actuation limitation, in a straightforward and unified way. This also means that the trade-off calibration between the economic objectives (by weight tuning) can be done with ease. Additionally, the convexity of the underlying optimization control problem (OCP) guarantees that a globally optimal solution can be found with high numerical effectiveness, which may lead to real-time feasibility. This thesis, in particular, is focused on the development of a unified CEMPC framework, combining the potentials of two emerging CEMPCs in the wind turbine area, namely the power-and-energy CEMPC and the quasi-linear parameter-varying model predictive control (qLPV-MPC), for addressing multiple wind turbine structural loads.
The former achieves its convexity by exchanging nominal wind turbine variables, such as blade pitch, generator torque, and rotational speed, with alternative variables in terms of aerodynamic and generator powers and rotor kinetic energy. This results in the OCP containing linear dynamics, convex constraints, and concave objectives to be maximized. Being originally focused on fulfilling power gradient requirements from a grid code, a fatigue load mitigation consideration was introduced later on for fore-aft tower motion in the literature. Unfortunately, little attention was paid to the mitigation of the more weakly-damped side-side tower loading, as well as blade fatigue loads.
Such a knowledge gap is filled in this thesis; in particular, both key components' fatigue loads are mitigated by exploiting the individual blade pitching capabilities of the power-and-energy CEMPC framework. Since, in this framework, blade pitch actuation is achieved mainly by manipulating aerodynamic power inside the CEMPC, a redefinition of the latter is necessary to enable such a feature. To be precise, multiple aerodynamic powers, each representing that of a single blade, were employed as decision variables of the CEMPC instead of a single quantity. Further mapping of the aerodynamic powers into side-side blade forces, as well as augmentation of side-side tower dynamics into the CEMPC's internal model, enables counteractive control actions for reducing side-side tower load. Mapping the powers into blade and rotor moments enables alleviation of the blade loads.
On the other hand, the utilization of qLPV-MPC for deploying a passive wind turbine tower resonance prevention by dynamically optimal frequency skipping has been gaining attention in the literature. For enabling active load cancelation in this framework, however, a periodic load estimation is needed. In this thesis, such an estimation scheme is developed, employing a Kalman filtering method. Aligned with the qLPV-MPC implementation for the aforementioned passive method, the internal model of the filter is rendered in a demodulated fashion by applying a model demodulation transformation (MDT) to an extended wind turbine side-side tower dynamics. Measurement signal demodulation (MSD) is utilized for capturing the slow-varying components of wind turbine tower measurements to be fed to the Kalman filter. The filter is thus capable of not only estimating the demodulated periodic load signals but also those of the unknown and unmeasured tower states with good agreement with the ground truth.
The next challenge addressed in this thesis is the provision of an active control method specifically aimed at tackling the side-side periodic loading of the tower. A family of repetitive control methods, namely modulation\-/demodulation control (MDC), is adopted in this thesis to handle the cancellation of the periodic loading. In principle, MDC consists of output signal demodulation, projecting the frequency component of interest (namely the rotor frequency) in the signal into low-frequency quadrature and in-phase representations. On these axes, diagonal single-input, single-output (SISO) controllers can be designed, resulting in control signals, which, by a modulation process, are translated into a single control signal, being an additive generator torque signal, oscillating at the frequency of the disturbance and thereby canceling it. A phase offset, with its optimal value determined by the plant's phase at the disturbance frequency, is needed and included in the modulation. This results in the full decoupling of the control channels, as well as the correction of an occurring gain sign flip due to the varying excitation frequency, which could have deteriorated the controller's performance and induced instabilities. The MDC extends a conventional tower damper controller specifically aimed at mitigating the tower loading at its natural frequency. As a result, both the tower load components at the natural frequency and the rotor frequency are mitigated simultaneously.
This thesis has, thus, highlighted the significant role various coordinate transformations play in advancing state-of-the-art wind turbine control, be it a transformation of signals into a different set of variables in power and energy terms or into different time scales. The former has enabled the formulation of power-and-energy CEMPC for side-side tower load and blade loads mitigation, extending this framework's fatigue load mitigation capabilities. The latter transformation, demonstrated by the MDT, paves the way for estimating unknown and unmeasurable periodic load and tower states in a demodulated manner, essential in activating the periodic load cancelation feature of the novel qLPV-MPC method. The MDC method has successfully enabled active side-side periodic tower load cancelation by leveraging a modulation-demodulation scheme, another way of transforming coordinates into different time scales where convenient yet effective control system design can be made. This thesis has, therefore, provided elements required for constructing a unified CEMPC framework, where the benefits of the said coordinate transformations may be further harnessed.","","en","doctoral thesis","","978-94-6366-842-2","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:f7da4ec8-6399-4d65-b087-3daa829e24fd","http://resolver.tudelft.nl/uuid:f7da4ec8-6399-4d65-b087-3daa829e24fd","Sub-L1 Halo Orbit Control Using Solar Sailing: FPF and Heliogyro Sails","Pignacca, Emma (TU Delft Aerospace Engineering)","Mooij, E. (mentor); Delft University of Technology (degree granting institution)","2024","This study analyzes the orbit control performance of solar sails for Sun-Earth sub-L1 halo orbits, which are particularly interesting for solar observation missions. Heliogyros are a promising alternative to the more widely employed Fixed Polygonal Flat (FPF) sails due to their potential to enhance maneuverability. The heliogyro coupled roto-translational dynamics model is tested for the first time in the interest of orbit control, and a new method is developed to validate and verify the model. While achieving a fully functional heliogyro controller remains challenging due to slow attitude control, the developed design shows potential for future improvements. Furthermore, a new Linear Quadratic Regulator (LQR) that employs a hybrid error approach is designed for the FPF sail. Compared to previous research, the new LQR shows improvements in terms of allowable injection errors: the combinations of allowable initial position and velocity errors double with looser performance constraints and almost triplicate for stricter constraints.","","en","master thesis","","","","","","","","2025-05-02","","","","Aerospace Engineering","",""
"uuid:1a33592a-b77b-46e3-abac-cb7cc34ea26a","http://resolver.tudelft.nl/uuid:1a33592a-b77b-46e3-abac-cb7cc34ea26a","Development of a passive SHM impact damage detection method for monitoring composite aerospace structures","Voges, Jordy (TU Delft Aerospace Engineering)","Groves, R.M. (mentor); Grooteman, Frank (mentor); Sodja, J. (graduation committee); Sinke, J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Safety and reliability of aircraft structures are of main concern within the aerospace industry, preferably without influencing the availability of the aircraft and maintenance and operation costs. As damages in composites can be hard to detect, methods are being developed to detect damages which can potentially lead to a (catastrophic) failure of a (sub)system. Interest in structural health monitoring (SHM) has thus gained a strong interest within aerospace engineering, with the development of new systems or optimising existing ones to contribute to a safe and reliable aircraft. This research focuses on the development of an impact damage detection and quantification method for composite structures. The main research objective of this thesis is to investigate the capabilities of a PZT and a state-of-the-art FBG sensor system for passive impact damage detection and quantification on a simple composite panel and a complex stiffened composite structure.","Structural Health Monitoring; Composites; PZT; FBG","en","master thesis","","","","","","","","2026-04-19","","","","Aerospace Engineering","",""
"uuid:158d75d1-e0f9-4547-bab3-3389e5c0e1f6","http://resolver.tudelft.nl/uuid:158d75d1-e0f9-4547-bab3-3389e5c0e1f6","Input design and data-driven approaches based on convex optimization for fault diagnosis in linear systems","Noom, J. (TU Delft Team Michel Verhaegen)","Verhaegen, M.H.G. (promotor); Soloviev, O.A. (copromotor); Smith, C.S. (copromotor); Delft University of Technology (degree granting institution)","2024","The complexity of automated systems has grown considerably during the past decades. This convolutes the observation of possible faults in these systems. If not being revealed timely, such faults can lead to catastrophic failures. As a result, there is a continuous interest in sophisticated fault diagnosis techniques. Since it is generally desired to diagnose faults in the earliest possible stages, computational challenges are imposed on the algorithms. Whereas the field of fault diagnosis comprises of a large variety of techniques in various categories, these computational challenges appear to emerge wide-ranging.
At the same time, convex optimization has developed as a valuable tool to solve a large variety of mathematical problems with computational efficiency. This computational efficiency is achieved by exploiting favorable structures of the problem. Depending on the specific problem, these structures vary in difficulty to be recognized or arranged. Moreover, some problems lead to a convex optimization problem naturally, while other problems first need some kind of relaxation or sequential process in order to employ convex optimization.
This thesis explores how convex optimization can be utilized in order to solve fault diagnosis problems with computational efficiency. The state-of-the-art is studied for multiple computationally challenging categories of fault diagnosis: online input design approaches, diagnosis of many concurrent faults, and data-driven approaches. First, online input design approaches facilitate fault diagnosis by computing discriminating input sequences during system operation. Since the input is calculated in real-time those approaches allow only limited computational effort, whereas adequate input determination typically appears to be nontrivial. In this contribution it is shown that an established upper bound on the error probability for linear candidate models with Gaussian noise is concave in the most challenging discrimination conditions. This finding allows to use sequential convex programs for online determination of a discriminating input with low computational effort.
The second contribution in this thesis regards the cantilever dynamics in high-speed atomic force microscopy. Due to the oscillatory behavior above the scrutinized sample, the cantilever typically has intermittent physical contact with the sample. This leads to a large number of (dynamically dependent) impulsive faults. Instead of performing an intractable explicit examination of all (combinations of) hypotheses, this contribution applies sparse estimation as a convex optimization method in order to diagnose these concurrent faults. In a simulation study, the resulting effect on the sample height reconstruction is discernible both qualitatively and quantitatively with respect to the conventional approach to sample height reconstruction in atomic force microscopy.
The third contribution introduces a novel problem formulation for model-free data-driven fault diagnosis. Instead of separate time periods for system identification and fault diagnosis in typical data-driven approaches, model-free data-driven fault diagnosis aims for the simultaneous system identification and fault diagnosis from one single data set. Whereas this is originally a non-convex bilinear problem, a proposed solution reformulates it as a convex optimization problem using a so-called lifting technique. Furthermore, online evaluation of this optimization problem is facilitated by a developed recursive implementation. The proposed methodology is tested both on simulation data and real-life flight test data.
By demonstrating the potential of convex optimization to a deliberate selection of fault diagnosis problems, this thesis serves as a source of inspiration for solving a wider variety of fault diagnosis problems efficiently. Furthermore, various elements related to convex optimization and its recursive implementation presented in this thesis have additional relevance to the general field of control science beyond fault diagnosis. Future applications of the presented methodology can arise for instance in the data-driven control in the presence of disturbances, or recursive blind deconvolution of real-time image sequences.","Fault diagnosis; Convex optimization; Kalman filtering; System identification; Linear systems","en","doctoral thesis","","978-94-6384-567-0","","","","","","","","","Team Michel Verhaegen","","",""
"uuid:4cd5e33e-ffe2-49cf-a9e0-8012f85bff65","http://resolver.tudelft.nl/uuid:4cd5e33e-ffe2-49cf-a9e0-8012f85bff65","Exploring financial inclusion among small-scale farmers: The case of small-scale horticulture in Ghana","Kuijt, Olav (TU Delft Technology, Policy and Management)","Scholten, V.E. (mentor); Roosenboom-Kwee, Z. (mentor); Wakeling, G.M. (mentor); Delft University of Technology (degree granting institution)","2024","","","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:8b8e923f-6635-4320-8fd7-cc29d562e00d","http://resolver.tudelft.nl/uuid:8b8e923f-6635-4320-8fd7-cc29d562e00d","Distributed Multi-Agent Pathfinding","Scheepstra, Karel (TU Delft Mechanical Engineering)","Atasoy, B. (mentor); Dabiri, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Multi-agent path finding (MAPF) is the task of finding non-conflicting paths for multiple agents that operate in a environment with shared resources.
Finding an optimal solution quickly becomes intractable for many applications and consequently suboptimal methods are also explored extensively in literature.
This work presents the Decentralized Optimization (DECOP) algorithm: a novel receding horizon control algorithm that exploits insights from MAPF research as well as decentralized control. In the proposed framework, each travelling agent communicates with agents in its proximity to solve a local MAPF problem that considers only a selected tractable number of agents. Inter-agent cooperation and conflict free operation are induced through applying a common local optimization policy during parallel local optimization and through a subsequent path reservation scheme based on random priorities. Inter-agent communication consists of sharing respective route alternatives from which additional information with regard to an agents' entanglement can be inferred which can also be included in the local optimization cost function.
Comparative results with other decentralized algorithms show that the DECOP algorithm yields competitive results while guaranteeing conflict free operations, with limited required communication and without the need of any training time. Among many degrees of freedom to be explored further, including information about the entanglements of an agent's route alternatives in the common policy for local optimization yields an increase in performance and suggests an increased extent of induced cooperation.","MAPF; Pathfinding; decentralized control","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:2a32df49-6a3b-4384-bfa3-3b10b5e65953","http://resolver.tudelft.nl/uuid:2a32df49-6a3b-4384-bfa3-3b10b5e65953","Towards the Integration of Additive Manufacturing for Freeform Steel and Glass Façade Construction","Tramontini, L.M. (TU Delft Architectural Technology)","Knaack, U. (promotor); Turrin, M. (promotor); Klein, T. (promotor); Delft University of Technology (degree granting institution)","2024","The thesis, titled ‘Towards the Integration of Additive Manufacturing for Freeform Steel and Glass Façade Construction,’ explores the transformative role of additive manufacturing (AM) in enhancing the design and construction of Freeform Steel and Glass Façades (FFSGF). These façades involve intricate components, necessitating collaborative efforts among designers, engineers, and fabricators to achieve complex façade geometries with good performance while ensuring efficiency in design, material usage, fabrication, and cost. Recent advancements in AM technology have made it a potentially viable and increasingly accessible fabrication strategy, particularly for mass-customized components such as those used in freeform construction. The research aims to answer the central question of how AM can effectively contribute to developing node solutions supporting Freeform Steel & Glass Façade (FFSGF) construction.The study systematically examines opportunities for improvement in existing solutions. Chapters 2 and 3 provide a critical overview of FFSGF construction typologies and explore the current landscape of AM in façade applications. Chapters 4 and 5 delve into the design and development of crucial components—structural nodes and gasket nodes—utilizing different AM technologies. Prototypes are manufactured and evaluated in comparison to existing solutions. Chapter 6 provides a case study of integrating AM product development into a larger construction project, emphasizing interdisciplinary collaboration. The thesis underlines the advantages of the systemization of AM node design throughout the design and fabrication of AM nodes. This research contributes to the evolving knowledge at the intersection of design, engineering, construction, and AM, aiming to provide a valuable resource for building industry professionals navigating the complexities of incorporating AM into the fabrication of freeform steel and glass façades.","","en","doctoral thesis","A+BE | Architecture and the Built Environment","978-94-6366-848-4","","","","","","2025-04-18","","","Architectural Technology","","",""
"uuid:c69c9360-cdcd-4b61-9fc3-5e6bec67c523","http://resolver.tudelft.nl/uuid:c69c9360-cdcd-4b61-9fc3-5e6bec67c523","Reduced-complexity Teleimpedance Command Interface Enabling Single-handed Control of 3D Stiffness for Unstructured Tasks","Kraakman, Frank (TU Delft Mechanical Engineering)","Peternel, L. (mentor); Delft University of Technology (degree granting institution)","2024","The state-of-the-art teleimpedance command interfaces used to command the robot stiffness configuration are either too complex to set up, such as those that use physiological signals and other tracking methods or cannot configure the stiffness appropriately for 3d environments.
To mitigate these issues, a novel teleimpedance interface is proposed.
The proposed interface can independently control the stiffness configuration's shape, orientation, and size with single-hand operations while allowing the operator to use that hand to command the robot's position.
The teleimpedance interface is attached to the operator's hand and uses two scroll wheels, a joystick, and a force sensor to configure the robot's stiffness and has two different modes of operation.
Compared to the state-of-the-art methods, the main advantage of the proposed teleimpedance command interface is that it does not require additional hardware with force feedback or complex setup calibrations while allowing for control of the robot's 3D stiffness configuration with single-handed operation.
An experiment with human subjects was performed to demonstrate the proposed interface's acceptance and functionality.
To demonstrate the teleimpedance command interface's ability to adjust 3D stiffness configurations a teleoperation was performed, utilizing a Kuka robotic arm and a Force Dimension Sigma7 position input interface.
The teleimpedance interface functioned as intended during teleoperation in a 3D environment to configure and adjust the 3D stiffness configuration for the task in real-time.
The results from the human subject trials indicate that the participants can successfully operate the interface to complete the alignment tasks in both modes for 3D stiffness configurations.","Teleimpedance; teleoperation; real-time impedance adjustment; robotics; Stiffness Command Interface; Impedance Command interface","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Biomechanical Design - BioRobotics","",""
"uuid:ab99217e-5ae7-4322-b4c9-311547a3feb9","http://resolver.tudelft.nl/uuid:ab99217e-5ae7-4322-b4c9-311547a3feb9","Product lifetime extension through design: Encouraging consumers to repair electronic products in a circular economy","van den Berge, R.B.R. (TU Delft Responsible Marketing and Consumer Behavior)","Mugge, R. (promotor); Magnier, L.B.M. (copromotor); Delft University of Technology (degree granting institution)","2024","Our production and consumption patterns of electronic products exceed the limits of what one planet can handle. Prolonging product lifetimes decreases the value losses caused by the destruction of existing products and lowers the amount of e-waste. Repair is an impactful strategy to tackle the issues associated with the production and consumption of electronic products. However, most discarded products are never repaired during their lifetime. Literature proposed several design for repair strategies, predominantly from a technical (engineering) perspective. However, a technically repairable design may not automatically result in repair behavior. Consumers and their behavior play a key role in prolonging the lifetimes of our daily used products.
The objective of this thesis is to explore the role of design in stimulating consumers to extending product lifetimes via repair. A consumer perspective investigates why consumers decide to prematurely replace products and their barriers towards repair. Design and marketing strategies to stimulate repair (e.g., support in failure diagnosis, modularity, and lifetime labels) are identified from literature. The effectiveness, boundaries and the required conditions of these strategies are tested in several empirical studies. They showed that high perceived repair self-efficacy, explicit cues guiding the repair act, and specific information about product’s reliability and upgradeability can increase consumers’ repair intentions.
By adopting a consumer-centric approach, this thesis offers contributions to design research on product lifetime extension and repair. However, creating a repairing society is not solely a consumer’s responsibility. One should realize that product lifetime extension requires a shift in current industry practice and businesses organization, as well as the design of appropriate policies. Therefore, a systemic approach and cooperation between all involved stakeholders is required. Designers, researchers and policymakers can use our insights to stimulate much-needed consumer repair practices of (electronic) products within a circular economy.
Various modelling approaches are explored, building on a finite element model of the Flying-V developed in previous work. Drop tests validate optimal section designs, emphasizing a minimum vertical impact velocity. Spatial variations in Dynamic Response Index (DRI) and Severity Index (SEV) prompt nuanced studies on impact scenarios and potential passenger side loads.
As the analysis progresses, extending the computational domain becomes crucial for reliability. Insights into weight distribution imbalances and challenges with corrective measures emerge from analyses of extended fuselage sections. Spatial fluctuations in DRIs and SEVs underscore the need for a balanced approach between computational efficiency and result realism.
A newly introduced modelling technique leveraging moments of inertia is implemented, yielding realistic results for straightforward scenarios and reducing simulation time significantly. Further analysis explores intricate landing scenarios, highlighting differences between full and reduced models, particularly at elevated pitch angles.
Recognizing the limitations of simplified methodologies, a submodelling technique is proposed for extreme crash scenarios, effectively capturing engine section dynamics with reduced computational time.
While reduced modelling techniques show promise, the study underscores the need for a comprehensive finite element method representation of the Flying-V, recommending successive simulations with a coarse overall mesh followed by submodelling for detailed assessment of critical regions.
Securing electronic devices requires the use of cryptographic algorithms and trusted execution environments (TEEs). Cryptographic algorithms ensure data confidentiality and integrity through encryption/decryption, hashing, and digital signatures. TEEs provide secure enclaves within the system for critical operations that prevent unauthorized modifications and access by imposing stringent access restrictions. These two measures have become robust mechanisms for enhancing the security of critical operations and data access control.
Despite the above security measures, electronic systems are susceptible to various attacks, including side-channel analysis (SCA), in which attackers exploit information leakage from physical devices while executing instructions or cryptographic algorithms. Power consumption and electromagnetic radiation (EM) are common indicators of this leakage. Countermeasures such as masking and hiding techniques are commonly employed to enhance resistance against SCA. However, the advent of deep learning in SCA has brought forth new challenges, rendering previously efficient countermeasures ineffective. Moreover, deep learning-based SCA has the potential to eliminate preprocessing and alignment requirements inherent in earlier methods.
Therefore, this thesis focuses on two main objectives. The first objective is the implementation of cryptographic algorithms and the incorporation of TEEs for secure-sensitive applications. HW/SW co-design approach will be utilized to attain optimal performance while preserving flexibility. The second objective of this thesis is the investigation of deep learning-based SCA to explore its effectiveness in detecting side-channel vulnerabilities.","Electronic Systems; Security; HW/SW Co-design; Cryptographic Algorithms; Trusted Execution Environments; Side-channel Analysis","en","doctoral thesis","","978-94-6473-466-9","","","","","","","","","Cyber Security","","",""
"uuid:54df635c-e675-4821-842a-0fd17223722c","http://resolver.tudelft.nl/uuid:54df635c-e675-4821-842a-0fd17223722c","Design of a measurement tool for objective stiffness measurements in the MCP joints of rheumatoid arthritis patients","Bosselaar, Chris (TU Delft Mechanical Engineering)","Smit, G. (mentor); Mugge, W. (graduation committee); Van Mulligen, Elise (graduation committee); Delft University of Technology (degree granting institution)","2024","b>Background
Rheumatoid arthritis (RA) is a progressive, chronic, inflammatory, autoimmune disorder, affecting 0.5-1.5% of the world's population. Current RA disease activity assessment methods rely on subjective, labor-intensive methods. Therefore, an unmet need exists for objectively assessing RA disease activity through a low-labor method. It is hypothesized that a correlation exists between passive MCP joint stiffness and RA disease activity.
Objective
The objective of this study is to design, develop, and evaluate a measurement tool that can assess passive MCP joint stiffness of the index-, middle-, and ring fingers of both hands objectively. The tool will be evaluated on healthy participants.
Design methods
A structured approach is adopted for the design of the measurement tool. The design challenges are mapped out by writing down the requirements into four categories. In the next design phase, the partial functions and their corresponding potential solutions are worked out. Three concepts are developed which combine different sets of potential solutions. The most promising concept is determined through a multicriteria analysis and worked out into a final design. Before the evaluation process commences, the final design is reflected on and improved where necessary.
Evaluation methods
Firstly, the tool is verified by subjecting it to a linear torsion spring rather than a human MCP joint. Secondly, the passive resistance behavior of a human MCP joint is analyzed during a full cycle of flexing and moving back to the initial position. Thirdly, the tool is used for an inter-day evaluation to determine the precision of the tool when used on human MCP joints (expressed as coefficient of variation (CV)). Finally, a repetition test is performed to determine the influence of setup-related causes on the precision of the tool.
Results
The linear spring evaluation showed that the mechanical system of the tool is very precise, exhibiting a coefficient of variation of 0.6%. The continuous cycle evaluation showed that the passive resistance of the MCP joint behaves nonlinearly and that the MCP joints have viscoelastic properties. The calculated CV for the inter-day precision evaluation is equal to 33.0%. The CVs for the repetition tests were equal to 13.4% and 27.7% for the fixed and non-fixed approaches respectively. Other evaluated aspects are the weight of the tool (1.6 kg), volume of the tool (10.8 dm3), comfort for the user (9 out of 10), and full six-joint assessment time (7.5 min).
Discussion
The CV of 33.0% for the inter-day precision evaluation is too large to subject the tool to RA patients. However, the repetition test showed when the hand under assessment is consistently aligned and orientated, the system is much more precise, exhibiting a CV of 13.4%. So, when design components are included that assist with the alignment and orientation of the hand under assessment, the tool can be subjected to actual RA patients to evaluate the increase in passive MCP joint stiffness during (the early stages of) inflammation.
Two surrogate modeling approaches are employed: semi-surrogate modeling and full-surrogate modeling. In the semi-surrogate modeling approach, a small number of RFEM simulations are conducted for a specified case. The machine learning models are trained using the generated random fields as input data and the calculated factors of safety as output data. The mathematical models are then used to predict outcomes of FoS for a large number of random fields for the same specific slope case. In the full-surrogate modeling approach, many RFEM simulations are conducted for the training set, covering a range of spatial correlation lengths. Once trained, the full-surrogate models are ready for application to another different slope case without the need for any additional numerical simulation.
The results indicate that the prediction accuracy of the ML models typically decreases for slope cases with smaller scales of fluctuation. Nonetheless, the FoS predictions by the best-performing semi-surrogate model are highly consistent with the results from RFEM simulations for the whole range of considered slope cases. In terms of predicting the probability of failure for 2D-modeled slopes, the accuracy is high, with relative errors within 10% across the cases considered. This level of accuracy is achieved using no more than 13% of the total number of realisations needed for RFEM analysis. Consequently, the computational time for reliability analysis involving 4000 realisations reduces from 67 hours using the RFEM to between 4 and 8 hours using a semi-surrogate model, with the time increasing as the spatial correlation length decreases. Predicting the p_f for 3D slopes using a semi-surrogate model showed larger errors, indicating a need for improvement.
The full-surrogate models prove to be accurate for testing cases characterised by spatial correlation lengths within the training set's range. Notably, the best-performing full-surrogate model in 3D predicted the p_f within a relative error of 10% for two slope cases. This model performs a stochastic analysis of 4000 simulations within seconds, compared to 83 days of computational time required for RFEM reliability analysis.
For various reasons, it can happen that a client is overpaid and needs to repay the excess amount to UWV. If the excess amount cannot reasonably be deducted from the client's monthly benefit, UWV's internal department, Verwerking Financiële Verplichtingen (VFV), handles the repayment process and assists clients in finding suitable payment options.
In addition to being unemployed, some of UWV's clients have financial debt that affects their ability to take action and be in control of their finances. These clients, in particular, face great difficulties during the repayment process with VFV. UWV would like to better serve these clients by giving them more control over their financial situation. While UWV has already conducted research on how clients experience the repayment process and is already developing digital services to support them, further insights were needed on how to address these clients' needs, how to develop solutions that serve these clients in a supportive and inclusive manner, and how to address their underlying needs.
In this design project, I used a User-Centered Design approach to gain a deeper understanding of the underlying needs of clients with financial debt and the difficulties they encounter during the repayment process. I discovered that clients with financial debt can perceive the initial notice about the repayment as a great and unexpected shock. These clients have an unmet need for more personal and proactive support from UWV. They do not feel seen and heard during their interactions with VFV and UWV's general helpdesk, and they lack perspective throughout the lengthy repayment process.
Through various design activities, including a co-creation session with clients from UWV, I designed a service concept tailored to the needs of VFV's clients with financial debt. This concept offers clients a kinder, softer introduction to the repayment process from VFV and provides personalized and proactive support through face-to-face or online service meetings with a designated employee from VFV. For this service concept, I designed four service touchpoints: an invitation card to kindly and personally invite the client to the meeting, a checklist for clients to prepare for the meeting in manageable steps, a note-taking sheet for clients to record expectations and agreements made during the service meeting, and several card designs to provide clients with a monthly overview of their payments to UWV.
Once UWV further develops and implements this service concept, I expect that clients with financial debt will feel more supported, seen, and heard by employees of VFV. Furthermore, I expect clients to be more inclined to get in contact with VFV due to the kind invitation beforehand and the personal relationship built with their designated contact at VFV after the service meeting. Consequently, this service is also expected to work preventively to avoid bigger financial problems in the future as a result of clients staying in contact with VFV.","User-Centered Design; Service Design; Debt; Co-creation","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:404db306-a85f-46ac-80d0-ba2a4f24a26e","http://resolver.tudelft.nl/uuid:404db306-a85f-46ac-80d0-ba2a4f24a26e","Complementarity and Similarity in Complex Networks","Budel, G.J.A. (TU Delft Network Architectures and Services)","Van Mieghem, P.F.A. (promotor); Kitsak, M.A. (copromotor); Smeitink, E. (copromotor); Delft University of Technology (degree granting institution)","2024","Networks are becoming ever more important in today's highly interconnected society, from telecommunication networks and social networks to power grids and the Internet. The field of Network Science seeks to uncover structure within the complex topologies of networks and the processes that govern their link formation. Many methods and models in the field are founded on link-formation principles that are driven by similarity, drawing inspiration from social network theory. In this dissertation, we discuss various network representations based on similarity, and we introduce and illustrate an alternative link formation principle that is based on complementarity.
The first part of this dissertation focuses on clustering the nodes of a network or community detection. Here, the nodes of a network are partitioned into several clusters and the objective is to precisely determine the cluster memberships based on only the network topology. Many clustering methods assume that the true number of clusters is known a priori. In Chapter 2, we investigate how exactly to find this number of clusters for a given graph. We discuss several modularity maximization and spectral clustering methods, and we outline how they can be used to find the number of clusters. We compare the performance of several different algorithms by evaluating these methods on benchmark graph models where the ground truth clusters are known.
In the second part, we explore network representations in the hyperbolic space. In Chapter 3, we extend the 2-dimensional random hyperbolic graph model to a hyperbolic space of arbitrary dimensionality. Our rescaling of the model parameters and variables casts the random hyperbolic graph model of any dimension to a unified mathematical framework, such that the degree distribution is invariant to the dimensionality of the space. We analyze the different connectivity regimes of the model and their limiting cases. In Chapter 4, we describe how hyperbolic graphs are built on a connection principle based on similarity, and we identify a class of real-world networks in which the links are driven by principles of complementarity rather than similarity. We propose a framework for embedding complementarity-driven networks into hyperbolic space and we describe the ensuing complementarity random hyperbolic graph model. In Chapter 5, we further investigate the topological properties of the complementarity random hyperbolic graph.
The third and final part of the dissertation centers on semantic networks, which describe semantic relations between words or concepts. In Chapter 6, we systematically analyze the topological properties of a large, multilingual dataset of semantic networks. Our investigation covers both universal and language-specific structural properties of these networks. We examine the roles that the connection principles of similarity and complementarity play in their link formation, and we discuss how a deeper understanding of these organizing principles benefits applications in natural language processing.","Complex networks; Complementarity; Similarity; Hyperbolic geometry; Network clustering","en","doctoral thesis","","978-94-6366-845-3","","","","","","","","","Network Architectures and Services","","",""
"uuid:c36b0733-9b8f-4b65-afc3-1fd2e97a075a","http://resolver.tudelft.nl/uuid:c36b0733-9b8f-4b65-afc3-1fd2e97a075a","Blockchain and fairness in the VCM: Customer-Centric Fairness: Unraveling Blockchain's Potential in Voluntary Carbon Trading","Roza, Julian (TU Delft Technology, Policy and Management)","Roosenboom-Kwee, Z. (mentor); de Vries, G. (graduation committee); Delft University of Technology (degree granting institution)","2024","Carbon trading sets a price on greenhouse gases (GHG), enabling countries and companies to buy emission rights. The carbon market includes the compliant market, regulated by governments, and the voluntary carbon market (VCM), which lacks strict regulation and allows anyone to offset emissions. In the VCM, carbon credits are created through various projects and used to compensate for emissions elsewhere.
The creation of carbon credits in the VCM involves multiple stakeholders, including project developers, validation bodies, brokers, and customers. Given the differences in bargaining power between stakeholders, issues regarding fair revenue distribution exist.
Blockchain technology offers promise in addressing these challenges by providing transparency and accountability. Through blockchain-enabled platforms, customers can access real-time project information, verify emissions reductions, and ensure fair revenue distribution. This transparency fosters trust and empowers customers to make informed decisions.
Research on customer preferences regarding fairness in the VCM is lacking, highlighting the need to understand customer perspectives on fairness and how blockchain can enhance it. This study utilizes Q-methodology to explore customer views on fairness in the VCM.
Three perspectives on fairness, named factors 1, 2, and 3, emerged from the analysis. Factor 1 emphasizes community impact, Factor 2 focuses on market participation and intermediary responsibility, and Factor 3 highlights the importance of broker transparency.
Based on these findings, blockchain implementation should prioritize transparency, standardization, and credibility to increase trust and fairness in the VCM. Brokers play a crucial role in project selection, emphasizing the importance of trust and transparency. Blockchain should focus on increasing transparency throughout the project and carbon credit trading, simplifying information for brokers and enhancing market credibility. Increased transparency and understanding of project co-benefits can shift focus beyond emissions reduction, improving benefit-sharing in the VCM.
This research broadens the discussion on fairness in the VCM and underscores the role of brokers in enhancing trustworthiness and credibility. Brokers should stay actively engaged in blockchain developments in the VCM. However, challenges in blockchain implementation may arise, warranting further exploration.","Carbon trading; Voluntary Carbon Market; Fairness; Blockchain; Customers; GHG emissions; Q-methodology","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:30a09dbd-6950-4296-b70d-72134231ffbe","http://resolver.tudelft.nl/uuid:30a09dbd-6950-4296-b70d-72134231ffbe","Electrode Characterization for Neural Interfaces: Development of a testing platform for reliability and standardisation of results, validated via a characterisation study of subpar electrodes","de De Anta Dardagan, Pablo (TU Delft Mechanical Engineering)","Giagka, Vasiliki (mentor); Wilson, J.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Characterizing electrodes for neural interfaces is an essential step of the prototyping and manufacturing process. Sample performance can be modelled by conducting electrochemical measurements such as Electrochemical Impedance Spectroscopy, Cyclic Voltammetry, Voltage Transients and Noise characterization, providing insights for future use scenarios. However, parameters, techniques, and scientific reporting of results often fall short of a complete characterization and do not adhere to any standard.
A platform for accurate, reliable, and standardized electrode characterization was conceived to overcome these obstacles. It allows complete electrochemical characterization while providing a modular 3D-printed solution to securing the electrodes above the beaker. Additional parameters, such as electromagnetic isolation and control of the medium, are also accounted for. A complete characterization study of ENEPIG electrodes was carried out to validate the setup. Manufactured as circuit boards, not electrodes, several aspects of their electrochemical performance were lacking - mainly their survivability to the stress applied by the tests carried out. Testing parameters had to be determined to minimize structural damage while maximizing performance, akin to what would be desirable in a clinical setting.
Sensing characterization experiments identified a double-layer electrode structure and revealed that smaller electrodes exhibit capacitive behaviour in bandwidths one order of magnitude wider than larger ones. Stimulation characterization experiments ascertained that charge surface distribution would predominantly accumulate along the perimeter of the electrode. In conjunction with surface characterization, results indicate the flat surface of the electrodes prevents charge from being stored and injected optimally. Ultimately, the performance of the ENEPIG electrodes was measured with the injection-to-storage ratio at 10%, significantly inferior to other Au electrodes reported in the literature and utilized in vivo. As results accurately represented the sample population, characterization was deemed successful - validating the experimentation setup developed for this project.","","en","master thesis","","","","","","","","","","","","Biomedical Engineering","",""
"uuid:596eb25a-cf4f-4885-837f-ded6c1957f13","http://resolver.tudelft.nl/uuid:596eb25a-cf4f-4885-837f-ded6c1957f13","Assessment of different health monitoring techniques for damage characterization in a spar cap- shear web thick adhesive joint of a wind turbine blade","Khoshmanesh, S. (TU Delft Wind Energy)","Watson, S.J. (promotor); Zarouchas, D. (promotor); Delft University of Technology (degree granting institution)","2024","Developing an effective blade structural health monitoring (SHM) system is important for the wind energy industry. This has challenged the scientific communities for years, and still, the problem has not been solved. This research aims to find a solution to this problem and provide a basis for further research in this field. The failure rate and the downtime associated with wind turbine blades are relatively high. Within the framework of preventive maintenance, it is necessary to inspect wind turbine blades periodically. Blade inspection needs special tools, skilled manpower, vessels, and lifting equipment; therefore, it is costly. This is the main reason that the wind energy industry would like to minimize the number of periodic blade inspections by using a reliable SHM system. An issue that complicates the SHM of wind turbine blades is the complexity of blade geometry. Different parts of a wind turbine blade are connected using adhesive. These adhesive joints, e.g., leading edge, trailing edge, and spar capshear web adhesive joints, are important parts of the blade structure and play an essential role in the integrity of the blade. These joints are very vulnerable to fatigue damage. Manufacturing flaws and impact can instigate and accelerate fatigue damage in a wind turbine blade. Impacts may happen during the transportation or installation of the blades, especially for offshore wind turbines. In this study, vibration, acoustic, and infrared thermography are used to characterize fatigue damage in test specimens representative of the spar cap-shear web adhesive joint of a wind turbine blade. To create different levels of damage, the test specimens were subjected to fatigue tension tests. To study the effect of impact on damage propagation, the test specimens were subjected to different levels of impact using a Gas Canon machine before being subjected to fatigue tests. During the fatigue tests, a Polytech laser vibrometer, Vallen acoustic system, and FLIR infrared thermographic system were used for vibration, acoustic and thermographic analysis...","Acoustic emission; Vibration analysis; Infrared thermography; Adhesive joint","en","doctoral thesis","","978-94-6384-565-6","","","","","","","","","Wind Energy","","",""
"uuid:b6f6e40b-c61e-4718-ae0b-baf731ad9809","http://resolver.tudelft.nl/uuid:b6f6e40b-c61e-4718-ae0b-baf731ad9809","Guiding Visual Attention to Relevant Flights in Supporting Air Traffic Controller Decision Making","Vijay Kumbhar, Ajay Kumbhar (TU Delft Aerospace Engineering)","Borst, C. (mentor); Mulder, Max (graduation committee); van Paassen, M.M. (graduation committee); Bombelli, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Enroute Air Traffic Controllers (ATCOs) determine the appropriate course of action by scanning radar displays to identify and select a flight that requires clearances to ensure safe and efficient operations within their airspace sector. After selecting a flight of interest, ATCOs visually compare the flight parameter displayed in the flight labels to assess the impact of potential flight control actions on the sector safety. Expected surge in global air traffic will make it difficult for ATCOs to compare flight parameters, leading to delayed responses and increased workload. This research proposes a flight filtering mechanism based on interacting flight trajectories with spatio-temporal proximities to guide ATCOs’ attention toward potential interaction flights after selecting a flight of interest. ATCOs will find potential interaction flights more saliently as non-interacting flights fade once the flight of interest is selected. This approach targets ATCO’s pre-attentive phase of visual processing, alleviating additional perceptual and cognitive efforts in finding and processing information during conflict detection and previewing clearances. Experiment results with eight subject matter experts as participants showed no significant differences in the safety, operator performance, and perceived workload while controlling traffic due to demanding task requirements and strategy variation among participants. Nonetheless, participants expressed positive feedback regarding the assistance offered by filtering in fading non-interacting flights. No significant differences in objective measures coupled with filtering’s positive perceptions indicate filtering did not negatively affect the performance, suggesting further research with optimal balance between task requirements and participant expertise to evaluate the flight filtering concept.","","en","master thesis","","","","","","","","2026-04-16","","","","Aerospace Engineering | Control & Simulation","",""
"uuid:1619db0f-53e9-4f31-bbdb-af8b2aad9c27","http://resolver.tudelft.nl/uuid:1619db0f-53e9-4f31-bbdb-af8b2aad9c27","Effect of bow thruster-induced loads on stone displacement near a quay wall: A field measurement","Winter, Theun (TU Delft Civil Engineering & Geosciences)","Hofland, Bas (mentor); Voorendt, M.Z. (graduation committee); van der Hout, A.J. (graduation committee); van der Vorm-Hoek, C.V.A. (graduation committee); Ruijter, Michel (graduation committee); Zoon, Arthur (graduation committee); Delft University of Technology (degree granting institution)","2024","The surge in demand for inland vessel goods transportation has necessitated the operation of larger vessels with increased drafts. These larger vessels generate significant induced loads from their more powerful bow thrusters during berthing and mooring. These loads can lead to scour, which ultimately results in instability of the quay wall. To counteract this, stone gradings are penetrated with colloidal concrete as bottom protection. However, prior studies indicate that the flow velocity profile perpendicular to a quay wall decreases more rapidly than guidelines suggest, implying a potential reduction in the extent of colloidal concrete application. This is relevant for the Netherlands, where a multitude of hydraulic structures, including an estimated 130 locks, are in need of renovation or replacement. \\
\noindent This study seeks to comprehend the impact of bow thruster-induced loads directly perpendicular to the quay wall, on stone displacement near a quay wall and this study compares the outcomes of this field measurement with existing guidelines and scale modelling. The research question is therefore: ''\textit{How can results from a full-scale test improve the design and performance of loose-rock bottom protection against bow thruster-induced loads for quay walls accommodating inland vessels?}''\\
\noindent In order to answer this question a full-scale field measurement is conducted with the largest inland vessel in Europe. During this field measurement, free flow tests were performed and bottom velocity, pressure fluctuations and stone displacement were determined. \\
\noindent The applied bow thruster power and under keel clearance are marked as two important parameters for stone displacement. For the impact of this applied bow thruster power and under keel clearance, a variety of scenarios is examined. After each scenario a survey is done to look at individual stone displacement. Velocity measurements are taken to get more information about the flow velocities. The velocities were measured relatively far away from the bottom, resulting in low velocities. The actual bottom velocity is determined by validating and using the findings of the scale modelling performed by \textcites{Deltares}.\\
\noindent Free flow tests are performed to directly measure the outflow velocity and compare it with existing guidelines. From these tests, it is concluded that the existing guidelines for outflow velocity result in an overestimation of the required $d_{n50}$, with a measured loss coefficient of 0.65 as opposed to the proposed 0.90. Even with the reduced loss factor for the outflow velocity, the bottom velocity calculated with the Dutch method guideline is higher compared to the actual bottom velocities, demonstrating again, as already indicated in prior studies, that the guidelines are too conservative. \\
\noindent The turbulence intensity values play a significant role in validating the findings derived from scale modelling conducted by Deltares. The measured turbulent intensity values show similarities with the earlier findings, indicating a turbulent environment and validation of the Deltares scale modelling. \\
\noindent Based on pressure measurements, it is estimated that at the onset of movement, the pressure differences of the turbulent eddies are in the order of 50 to 90\% of the critical force to cause stone movement. \\
\noindent The in this study developed parameter R = $\frac{V_0}{UKC} \cdot t \cdot \frac{1}{k_{sl}} \cdot C_R $ shows that an increase in applied bow thruster power, a decrease in under keel clearance, an increase in duration and in slope lead to a linear relation with the normalised cross-section area of the near-quay erosion hole. \\
\noindent In addition, the full-scale field measurement showed that the stone displacement predominantly occurs within the first two and a half meters of the bottom protection, suggesting a possible reduction in the width of the colloidal concrete application. For a fictive quay wall the suggested reduction is compared with the design following the original guidelines. The suggested reduction alternative could save 75\% of the amount of colloidal concrete and CO$_2$ emissions.","Stone stability; Field measurement; Bow Thruster; Quay wall; Turbulence; Propeller jet; Bed protection","en","master thesis","","","","","","","","","","","","Civil Engineering | Hydraulic Engineering | Hydraulic Structures and Flood Risk","",""
"uuid:78fcecc5-7b81-4d56-ab54-d24f622d96cd","http://resolver.tudelft.nl/uuid:78fcecc5-7b81-4d56-ab54-d24f622d96cd","The impact of Marine and Offshore Renewable Energy on the European Energy System Evolution","Mezilis, Lefteris (TU Delft Mechanical Engineering)","Lavidas, G. (mentor); Delft University of Technology (degree granting institution)","2024","The European energy transition policies aim to mitigate the effects of climate change by moving away from fossils and promoting both onshore and offshore renewable energy technologies. Although onshore renewables are driving the transition so far, policymakers believe that in order to achieve the targets, the power grid must have access to the theoretically abundant energy present in the oceans. More specifically, these targets suggest that by 2050, around the continent there should be at least 340 GW of marine and offshore renewables for EU member-states, in addition with 125 GW for the UK.
The present study investigates the role of marine and offshore renewable technologies in 100\% renewable energy scenarios, inspired by the European targets of 2030, 2040 and 2050. The assessment of their role is based on he upgraded version of the open-source PyPSA-Eur (Python for Power System Analysis - European Sector, v0.25.1) energy system modelling tool developed within the Marine Renewable Energies Lab (MREL) of TU Delft, the PyPSA-MREL-TUD. This version is designed to have access on wave and farshore wind resources. The PyPSA framework utilizes an extract of the entire ENTSO-e transmission network and ERA5 climate data. By using time-series of 2018 for both the energy demand and weather data, this energy system model attempts to find cost-optimal solutions for the configuration of the different components of the power system. The developments include the addition of three wave energy converters and two types of floating offshore wind turbines to the existing generators and their associated costs, as well as the upgrade of the spatial resolution of the GEBCO bathymetry dataset of the model. For wave power, the model can access shallow water, nearshore and farshore wave resources, while for wind power both bottom fixed and floating generators are sub-categorized according to their distance from shore. Two significant constraints of the model include minimum generator capacity constraints for wind and wave power, and 70 \% energy equity per country.
The analysis of the results focuses mainly on the generator and storage system configuration of the system. An emphasis was also given on the required expansion of the transmission grid, and the objective's investment and operational costs. What is initially observed is the impact of the spatial resolution of the ERA5 dataset on wave energy converter installations, which underestimated the energy potential profiles. Capacity constrained versions of the scenarios showed that wave energy has a higher average hourly market value, but is highly susceptible to seasonal patterns. Although the performance is better during colder periods, wave converters suffer the most during the warmer periods and are also the first generator type to be curtailed. While offshore wind turbines were installed all around the continent, with the best candidates being France, Baltic and Scandinavian countries, Greece and Romania, wave converters were installed mostly in Portugal, Ireland and Italy. However, the accessibility of every country to the sea basins varies. Country-specific analysis of the model implies that, for the 2050 horizon scenario, there is still a high level of dependability of landlocked countries on solar energy, on their neighbours and on storage systems. The overall line capacity must increase by a factor of two.","marine engine; Wave energy; Wave Energy Converter (WEC); Floating offshore wind turbines; Power System Model","en","master thesis","","","","","","","","","","","","Offshore and Dredging Engineering","",""
"uuid:d9cae0f9-23ca-45ab-83a1-0965014db6b7","http://resolver.tudelft.nl/uuid:d9cae0f9-23ca-45ab-83a1-0965014db6b7","High-Performance Multilevel Class-D Audio Amplifiers","Zhang, H. (TU Delft Electronic Instrumentation)","Makinwa, K.A.A. (promotor); Fan, Q. (copromotor); Delft University of Technology (degree granting institution)","2024","This thesis describes the analysis, design, prototype implementation, and measurement results of high-performance Class-D amplifiers (CDAs) for audio applications.","","en","doctoral thesis","","","","","","","","","","","Electronic Instrumentation","","",""
"uuid:ad6afd36-a6dc-40e0-a637-abdebb1ed43f","http://resolver.tudelft.nl/uuid:ad6afd36-a6dc-40e0-a637-abdebb1ed43f","Stochastic Neighbor Embedding for interactive visualization of flow patterns in 4D flow MRI","de Boer, Mitchell (TU Delft Mechanical Engineering)","Lelieveldt, B.P.F. (mentor); Vos, F.M. (graduation committee); van der Geest, Rob J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Flow visualization is an important topic in many scientific domains and has been an active field of research for many years. Many different methods of analysis can be used in order to analyze flow, however recently big progress have been reported on the manifold learning algorithms for high-dimensional data. This thesis investigates the use of Stochastic Neighbor Embedding (SNE) methods, t-distributed stochastic Neighbour embedding(t-SNE) and hierarchical stochastic Neighbor embedding (HSNE) for flow analysis. In this thesis the Manivault ,Veith et al., 2024, software platform has been used in order to create an interactive analysis tool for SNE methods used on flow data. This tool consists of a 3D viewer plugin that visualizes the full path lines and an existing scatterplot plugin that is used in order to interact with the created SNE maps. The experiments and comparisons reported in this thesis aimed to compare the use of t-SNE and HSNE for analysis of flow structures in 4D Flow MRI data. From this, it can be concluded both t-SNE and HSNE are useful for interaction with and analysis of 4D Flow MRI data. t-SNE can best be used in order to explore and analyze flow data in search for flow structures, and comparing flow patterns between subjects. HSNE on the other hand gives a better separation between different flow components, however at the expense of a less accurate preservation of vortices and other flow structures.","Manifold Learing; Flow Visualization; t-SNE; HSNE; 4D Flow Analysis; Flow structures; Vortex","en","master thesis","","","","","","https://www.dropbox.com/scl/fi/cvfuchp4v4z8npw1fmotm/velocity_timelapse_S112-D2.mp4?rlkey=u98ucfl8k72nbnpvl2z0xjand&dl=0 Video described in figure 4.3","","","","","","Biomedical Engineering | Medical Physics","",""
"uuid:5b79f756-46d9-4b09-85c9-7877489b9ae1","http://resolver.tudelft.nl/uuid:5b79f756-46d9-4b09-85c9-7877489b9ae1","Design And Evaluation Of An Innovative Running Blade With Improved Push-off And Variable Progressive Stiffness","van Wezel, Sterre (TU Delft Mechanical Engineering)","Smit, G. (mentor); Langlois, David (mentor); Delft University of Technology (degree granting institution)","2024","Running Specific Prostheses (RSPs) enable running for athletes with lower limb amputations. The RSP design is inspired by human ankle behaviour while running, aiming to replicate its dynamic properties. RSPs are produced using carbon fiber composites that exhibit elastic properties, allowing them to store and return energy. Unlike biological legs, RSPs cannot generate net positive mechanical power. Furthermore, current RSP designs limit ground reaction forces (GRFs) while running. In addition, current RSP designs lack stiffness adaptation to running speed, which is required to optimize running speed. Running speed is a crucial performance indicator, influenced by step length, step frequency, and ground reaction forces (GRFs). This study explores the design of an innovative RSP running blade with improved push-off and load-dependent stiffness, focusing on how it can affect running gait, speed, and user satisfaction for lower limb amputees. This research aims to provide insights into the performance of the RSP. Mechanical compression tests were performed to characterize prototype stiffness. In addition, insights into user satisfaction and running biomechanics were obtained through qualitative feedback and quantitative gait analysis from amputee participants.","","en","master thesis","","","","","","","","2027-04-15","","","","Biomedical Engineering | Medical Devices","",""
"uuid:ef2b136f-5317-49f5-b244-195d21e0128e","http://resolver.tudelft.nl/uuid:ef2b136f-5317-49f5-b244-195d21e0128e","The RepairHub: Design of a repair center to overcome Rotterdam citizens‘ barriers to repair","Henschel, Florian (TU Delft Industrial Design Engineering)","Magnier, L.B.M. (mentor); de Koning, J.I.J.C. (mentor); Delft University of Technology (degree granting institution)","2024","Consumer repair practices are detrimental to advancing the circular economy since they are a vital strategy for prolonging a product‘s lifetime and saving resources. Despite the need for repair services for a functioning circular economy, the practice of Repair for consumers has declined, and more and more citizens prefer product replacement instead of considering the Repair of consumer goods. Research suggests a general mismatch between consumer needs and repair service offerings. (Gobert et al., 2021). The Municipality of Rotterdam wants to facilitate circular behaviour for its citizens. The Municipality is opening a new recycling center with the adjacent Upcycle Mall. It is envisioned as a place for the citizens of Rotterdam to experience the aspects of a circular economy, including different circular economy practices, such as upcycling, recycling and reuse. Designing a Repair offering at the Upcycle Mall for small household electronics and textiles is the task set out to solve in this project.
The local provision of Repair is analysed and structured into four modes: self-repair, Professional Repair, Community Repair, and Non-Profit Repair. A particular focus was put on the local community repair organisations (Repair Cafes) and their challenges.
A literature review and an interview study on consumer behaviour regarding Repair identify the main barriers consumers face. The unique situation of the Upcycle Mall is analysed, and unique opportunities for interventions are identified.
Based on the research findings, a pivotal concept for the Upcycle Mall is proposed: The RepairHub. This repair center leverages its location to trigger repair actions. It introduces the Community Repair Concept as a center for education and links to and empowers the local Community Repair Organizations.The design proposal consists of eight concepts structured in three groups. Three activities to conduct in the RepairHub were designed:
RepairTogether: A convenient Repair Offer for visitors of the recycling center, to give their device another chance.
Sort & Fix: A center to sort, fix and clean the electric devices brought to the recycling center, to make them ready for resale in local Secondhand Stores.
RepairEducation: A concept to educate school classes on repair practices and include Rotterdams Repair Cafes in the Process
Complementing the RepairHub, a comprehensive signage system is designed to effectively guide people to the RepairHub and promote the local Repair Cafes. This system plays a crucial role in encouraging repair actions and making citizens aware of the local provision of Community Repair organisations. In addition, a website and flyer were created to promote these services further.
This thesis concludes with a set of final recommendations to the Municipality to support the Repair Culture and Provision in Rotterdam.
This thesis aims to combine these two systems, and presents the design of an integrated robot reminder system for people with dementia who live at home. It aims to address the problems of people with dementia forgetting important things, their low quality of life, and the stress experienced by their informal caregivers. The system consists of an animal-like robotic pet, which delivers reminders for important activities of daily living, such as eating or showering, directly to the user with dementia. It guides them to a location in the house, where a screen tells them what the reminder is for. Through sensors placed in the house, the system can sometimes automatically detect whether reminders have been completed, and can use contextual clues to send reminders at the best time. For example, it can avoid reminding someone to shower when there are visitors in their house.
Three research topics are explored in the thesis. The first topic is that of value-sensitive design. The two user groups, people with dementia and caregivers, both have values they want to see reflected in the system. Sometimes, these values may clash. For example, the usage of cameras would make the system provide better care and be more safe, but it would come at the cost of the privacy of the user. The conflict between these values is explored in this thesis. Secondly, the interaction between the robot and the person in the context of a reminder system is researched. It should be clear to a user that the robot is trying to convey a reminder. This is done using screens, placed in several places in the house. The robot will drive towards the person with dementia, guide them to one of these screens, and prompt them to look at it. The third topic relates to the software architecture and software engineering requirements. Private data should be stored securely, and the requirements should be written to make future development easy. Recommendations are made regarding the ideal setup of the system, ensuring proper security and usefulness. This is done in the form of a proposed software architecture, user stories, and formal software requirements.","Dementia; Assistive Robots; Reminder System; Value Alignment; Human-Robot Interaction; Assistive Technology","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:609be108-6fd4-4a24-8677-7d76bbec3515","http://resolver.tudelft.nl/uuid:609be108-6fd4-4a24-8677-7d76bbec3515","Fatigue debonding resistance of wrapped composite X-joints","Feng, W. (TU Delft Steel & Composite Structures)","Veljkovic, M. (promotor); Pavlovic, M. (copromotor); Delft University of Technology (degree granting institution)","2024","Steel jacket support structures for offshore wind turbine towers made of circular hollow sections (CHS) are becoming a competitive solution compared to monopiles in deeper waters. The current limitation to improving the durability and cost-effectiveness of the CHS structures is the low fatigue endurance of their welded joints. Fatigue-driven design of such structures usually leads to thicker profiles of steel members as well as costly welding of joints. Due to excellent corrosion and fatigue endurance, high strength-to-weight ratio, easy and locally made fabrication, fibre-reinforced polymer (FRP) composite materials have been widely used to strengthen welded CHS joints. Although this strengthening technique can enhance the resistance and fatigue performance of the welded CHS joints, welding still serves as the main way for load transferring in the joints. Therefore, welds remain the source of stress concentration and brittle fatigue failure. Recently, an innovative joining technique, wrapped composite joint, has been proposed at TU Delft. In this joint, the CHS members are connected through the composite wrap. Loads are transferred at the bonded composite-to-steel interface, and welding is completely avoided. While monotonic tensile tests have shown the superior stiffness and resistance of the wrapped composite joint over its welded counterparts, the fatigue performance of the joint still needs to be investigated.
As the first investigation of the fatigue behaviour of the wrapped composite joints, the present study focuses on the most unfavourable failure mode, debonding at the composite-to-steel interface. A typical joint geometry in the jacket support structures, the K-K joint, is chosen as the research object, which is simplified to be the uniplanar X-joint. The general objective is to accomplish knowledge sufficient to predict the debonding behaviour of CHS-wrapped composite X-joints under tensile cyclic loads.
To achieve that goal, the present work starts from the interface level, where the fatigue crack growth (FCG) properties at the composite-to-steel interface are characterised through fracture mechanics experiments, i.e. 4-point bending end notched flexure (4ENF) tests. The steel surface of the specimens is prepared with different roughness levels, and its impact on FCG properties is investigated. The obtained FCG properties provide the basis for predicting crack growth at the joint level. In the wrapped composite joints, friction exists at the composite-to-steel interface due to the confinement by the composite wrap, which may retard the crack growth. This phenomenon is quantified in cyclic tests on joints with simple geometry, i.e. the axial splice joint (A-joint), where the debonding crack growth is monitored through the 3D digital image correlation (DIC) system. At the joint level, tensile cyclic tests are conducted on the wrapped composite X-joints with different surface roughness and at different scales. Post-fatigue static tests are conducted to check the influence of cyclic loads on the residual resistance of the joints. Using the finite element model, the methodology to predict the crack growth and stiffness degradation of the wrapped composite joints is established, which can consider the interaction between debonding on the chord and brace members. The prediction methodology is validated against the test results and used in a probabilistic analysis to explain and reproduce the scattering test results. Finally, the failure criterion of the joints under cyclic loads is proposed to establish the design S-N curves.
The present study found that the surface roughness of the steel tube plays an important role in the FCG properties of the composite-to-steel interface. A minor increase of the surface roughness can significantly improve the joint’s fatigue performance, with the parameter C of the Paris curve decreasing over magnitudes. At the joint level, the wrapped composite X-joints exhibited steady stiffness degradation during the tests due to debonding propagation at the composite-to-steel interface. Joints with reduced surface roughness show deteriorated fatigue performance but still have longer fatigue life over the welded ones. By including friction at the interface, the finite element model gives reduced strain energy release rates (SERR) at the crack front as the crack grows. Thus, the main source of the crack growth retardation is explained and can be quantified. The numerical results match well with test results of X-joints considering different surface roughness, different load levels and scales, and the relationship between debonding on the chord and braces is obtained. By studying the variability of surface roughness and FCG properties, the probabilistic analysis can reproduce scattering of the test results. Finally, the design S-N curves are obtained based on the experimental and numerical results, taking 5% resistance reduction as the failure criterion.
The present study provides a methodology for characterising and predicting fatigue debonding behaviour, not only for wrapped composite joints but also for other large-scale bonded joints with complex geometry, enhancing the application of bonded joints in engineering structures.
We compare the baseline randomly selected points to three alternative strategies. First, we try alternate random distributions, playing with both the standard deviation, to create a more narrow cone around the victim point, and mean, creating bimodal distributions further away from the victim point. We find that for some datasets these can give up to $5$-$7\%$ improved performance on subsets of the dataset, but these improvements do not generalize to the remainder of the dataset. In general, as long as the distribution is wide enough to successfully find starting points we do not find a substantial performance change.
Secondly, we try to remove the randomness and attack from a fixed direction. For the simpler datasets we find it is possible for a starting direction to perform better than random starting points, but for larger datasets performance becomes much worse. We also try an attack from all main directions around the victim point, which we find performs much worse than $5$-$20$ times fewer random points.
Lastly, we create an attack strategy where we select the closest points that scored well on previously attacked victims. We find that on smaller test sets this gets outperformed by the baseline, but when we extend the attack and give more possible previously well performing starting points we match or outperform the baseline slightly.","Adversarial attacks; Tree ensemble; Cyber security; Adversarial Examples","en","master thesis","","","","","","","","","","","","Computer Science | Cyber Security","",""
"uuid:29c957ec-56be-4ae3-b9ac-896739453aac","http://resolver.tudelft.nl/uuid:29c957ec-56be-4ae3-b9ac-896739453aac","Responsive microgel-based inks for inkjet printing: Application for in-situ sensing on-a-chip","Lugtmeijer, Thomas (TU Delft Mechanical Engineering)","Bazyar, H. (mentor); Kontaxi, G. (mentor); Eral, H.B. (graduation committee); Hunt, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Inkjet printing is a technology that has been widely studied and implemented. The liquids that are used for inkjet printing can vary. There is the traditional ink which can be found in almost every household printer. But it is also possible to use inkjet printing to deposit drugs, proteins and nanoparticles on substrates. Inkjet printing has the ability to precisely deposit picoliters of liquid onto the substrate. Thus, reducing cost and waste when the material being used is expensive and/or of limited quantity. This project works with a LP50 PIXDRO inkjet printer. Another interest that gained traction in the scientific community are the stimuli-responsive microgels. These microgels are able to change their dimensions depending on the external stimuli and if this stimuli is removed from the microgel, it changes back to its original shape, thus it is a reversible process. This project uses a suspension of the stimuli-responsive microgel; poly(N-isopropylacrylamide)-coacrylic acid (pNIPAm). This microgel is responsive to temperature and pH. To deposit the pNIPAm suspension on the substrate, inkjet technology will be used. The printability of the pNIPAm will be determined by characterizing the physical and rheological properties. Such as the density, surface tension, viscosity and particle size of the pNIPAm beads. These properties will be compared to the ideal liquid requirements given by the print cartridge that will be used, a Fuijifilm Dimatix. To influence the surface tension three surfactants will be tested. These surfactants are Triton X-114 (TRT), Sodium dodecyl sulphate (SDS) and Hexadecyltrimethylammonium bromide (CTAB). Based on the results the and comparison to the requirements the surfactant Triton X-114 is chosen because it lowers the surface tension the most. While it has minimal to no affect on the pNIPAm particles. The next phase of the project is testing the printability of the pNIPAm. This is done by adjusting the waveform on the LP50 PIXDRO inkjet printer. As a result it is indeed possible to deposit pNIPAm on a substrate with an inkjet printer. After this step a SEM is used to investigate if the printed pNIPAm particles will form a monolithic layer. This monolithic layer is important when it comes to having a functional etalon. The pNIPAm particles form indeed a monolithic layer on the substrate. The last step is to see if there is a peak shift in the wavelength when the temperature is increased. The microgel based etalons that used an inkjet printer to deposit the micrgol show a peak shift. Therefore, it can be concluded that it is possible to use an inkjet printer to deposit pNIPAm on a substrate and that the pNIPAm particles behave according to literature. All the results of this project show that using an inkjet printer is a viable alternative for fabricating microgel based etalons.","pNIPAm; Inkjet Printing; Microgel Based Etalon","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:2ac46a6e-c97a-495a-b9d3-f65ec8c7cf2b","http://resolver.tudelft.nl/uuid:2ac46a6e-c97a-495a-b9d3-f65ec8c7cf2b","Structured light assisted coherent fourier scatterometry for physical parameter retrieval of nanostructures","Dou, X. (TU Delft ImPhys/Pereira group)","Urbach, Paul (promotor); Pereira, S.F. (promotor); Yuan, X.C. (promotor); Delft University of Technology (degree granting institution)","2024","In the semiconductor industry, the minimumelement size has stepped into nanometer level. To keep the functionality of fabricated nanostructures, there is a huge demand of a technique that can provide non-destructive inspection and allow for in-line or in-situ monitoring during the manufacturing process. Optical scatterometry, which uses the far-field optical scattering information to retrieve the geometrical features of a structure, is a suitable method. As a non-imaging technique, optical scatterometry does not produce images of the illuminated object. Optical scatterometry relies on retrieving nanostructure profile parameters by continuously comparing the given set of predicted signatures expected from a scattering experiment with the actual measured ones. Because we parametrize the structure with a limited set of parameters (i.e. we use prior knowledge of the structure), we can reconstruct the structure with a resolution beyond the diffraction limit. This technique is particularly valuable for characterizing micro- and nano-scale structures that are commonly found in semiconductor devices and integrated circuits ....","Scatterometry; structured light; nanostructure detection","en","doctoral thesis","","978-94-6384-570-0","","","","","","","","","ImPhys/Pereira group","","",""
"uuid:7cd49965-5106-4a28-8609-cbcb7aeec0d5","http://resolver.tudelft.nl/uuid:7cd49965-5106-4a28-8609-cbcb7aeec0d5","Rural futures for young adults: Rural development and regeneration in the Netherlands","Koreman, M.C.J. (TU Delft Urban Development Management)","Korthals Altes, W.K. (promotor); Spaans, M. (copromotor); Delft University of Technology (degree granting institution)","2024","Young adults are essential in the future of rural municipalities. They can revive places in decline and create new opportunities. But what future dreams, plans and opportunities do they have? Embark on a journey through the Dutch countryside to uncover the future dreams of young adults. Delve into the dreams, plans, and obstacles shaping the future of rural municipalities. Through the vibrant tapestry of cultural festivals, witness the revitalization of once-declining communities. Additionally, examine the innovative re-use of vacant farm buildings, offering promising opportunities for regeneration, economic growth and entrepreneurship.
However, amidst these prospects lies a challenge: the political landscape, where urban interests often overshadow rural needs. Shedding light on these dynamics and navigating its complexities, this research aims to empower rural communities. It suggests how to pave the way towards better policies for rural municipalities in the Netherlands. Where young adults can build their rural futures.","Young adults; Rural municipalities; Personal futures; Community-led; Rural development; Spatial justice; The Netherlands","en","doctoral thesis","A+BE | Architecture and the Built Environment","978-94-6366-841-5","","","","","","2024-04-12","","","Urban Development Management","","",""
"uuid:e2728850-8aea-4bbe-8068-e129dbe6f4ff","http://resolver.tudelft.nl/uuid:e2728850-8aea-4bbe-8068-e129dbe6f4ff","Lift-Induced Wake Re-Energization for a VAWT-Based Multi-Rotor System","Broertjes, Thomas (TU Delft Aerospace Engineering)","Sciacchitano, A. (mentor); Ferreira, Carlos (mentor); Bensason, D.Y. (mentor); Delft University of Technology (degree granting institution)","2024","In response to the urgent need for renewable energy amidst the escalating impacts of global warming, this study delves into the forefront of wind energy research, particularly focusing on the innovative Multi-Rotor System (MRS). The MRS concept offers a promising departure from the prevailing trend of scaling up traditional turbines, instead proposing a configuration comprising multiple smaller rotors mounted on a single support frame. This approach, identified for its inherent upscaling advantages, presents an opportunity to reduce costs and weight relative to conventional Horizontal Axis Wind Turbines (HAWTs). While the concept is not entirely novel, its application with Vertical Axis Wind Turbines (VAWTs) is. Recent studies have demonstrated the significant potential of the VAWT-based MRS, showcasing comparable power performance to large HAWTs while enhancing Operations and Maintenance (O&M) aspects. Furthermore, the adaptable support frames of the MRS facilitate the integration of wake control devices, such as external lift-generating wings, which introduce cross-flow loading to rapidly re-energize the wake. However, despite these advancements, understanding the wake dynamics within MRS systems, particularly concerning their implications for wind farm applications, remains limited.
The current work aims to investigate the intricate near-wake dynamics of the VAWT-based MRS and study the effects of external lift-generating wings on the deflection and recovery of the wake. To do so, a scaled wind tunnel model of such a VAWT-based system has been designed together with a set of removable high-lift wings. These, in turn, have been tested in the Open Jet Facility of the Delft University of Technology to gather insight into the behaviour of the near-wake. Tomographic Particle Image Velocimetry using Helium Filled Soap Bubbles has been deployed in combination with load measurements to gather data.
Load measurements revealed that the thrust coefficient behaviour of the MRS closely resembles that of single-rotor VAWTs, with an additional thrust induced when the external lift-generating devices are present, attributed to accelerated flow on the suction side of the wings. Furthermore, the PTV measurements have provided a detailed visualization of the near-wake, showcasing symmetric wake structures and lateral deflection induced by the presence of individual rotors. The introduction of external lift-generating wings significantly altered wake behaviour, inducing lateral contraction and promoting streamwise momentum recovery through enhanced vertical advection. Furthermore, analysis of velocity deficit recovery highlighted substantial improvements in power recovery behind the MRS with external wings.
The findings presented in this work underscore the potential of the VAWT-based MRS, particularly when such a system is equipped with lift-generating devices. The presence of such devices effectively manipulates the near-wake of the turbine, enhancing wind farm efficiency, and thereby advancing innovative wind energy solutions.","Wind Energy; Multi-Rotor System; multi-rotor wind turbine; Vertical Axis Wind Turbine; wake control; Wind Tunnel; Large-scale PTV; HFSB; Particle Tracking Velocimetry","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:94205e7b-a9ab-47ac-a3c6-a71aec2aa516","http://resolver.tudelft.nl/uuid:94205e7b-a9ab-47ac-a3c6-a71aec2aa516","Feasibility and accuracy of Received Signal Strength-based Multilateration for aircraft localization using crowdsourced data","Martjanova, Veronika (TU Delft Aerospace Engineering)","Sun, Junzi (mentor); Hoekstra, J.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","To verify the aircraft position provided by Automatic Dependent Surveillance-Broadcast (ADS-B)
transponders, multilateration (MLAT) technique incorporates time difference of arrival (TDOA) measurements at multiple ground-based receivers to estimate the corresponding distances between those and the aircraft. This approach requires precise time synchronization among receivers that can not always be guaranteed. Alternatively, received signal strength (RSS) measurements can be utilized to derive these distances. In this paper, crowdsourced RSS measurements from 43 receivers were used to construct parameterized signal propagation models that capture the relationship between RSS and distance. The quality of these models
was evaluated by examination of model parameter and estimated distance errors in both 2D and 3D. The results show that at most 26.3% of available RSS measurements could be represented by the models given the cut-off criteria for model parameter errors. Moreover, the models with higher parameter errors demonstrated poor ability to capture RSS measurements at greater distances. The localization errors in MLAT with TDOA were compared to MLAT with RSS where the later resulted in more accurate position estimation in cases where the receiver clocks were not synchronized. However, MLAT with TDOA generally produced significantly more accurate position estimation given the reliable timestamps of signal arrival. The assessment of localization accuracy using crowdsourced data resulted in root mean square errors of 118.1 meters in MLAT with TDOA and 9858.6 meters in MLAT with RSS in 2D, representing the best results obtained.","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:13a77d65-116f-44ca-aef8-6978e2185640","http://resolver.tudelft.nl/uuid:13a77d65-116f-44ca-aef8-6978e2185640","Reinforcement Learning for Flight Control: Evaluating Handling Qualities and Stability Properties of the PH-LAB","Jansen, Hidde (TU Delft Aerospace Engineering)","van Kampen, E. (mentor); Pavel, M.D. (graduation committee); Mooij, E. (graduation committee); Konatala, R. (graduation committee); Delft University of Technology (degree granting institution)","2024","Reinforcement Learning applied to flight control has shown to have several benefits over classical, linear flight controllers, as it eliminates the need for gain scheduling and it could provide fault-tolerance. The application to civil aviation in practice, however, is non-existent as there are multiple safety concerns. This research demonstrates the evaluation of longitudinal Handling Qualities of the Soft Actor-Critic Deep Reinforcement Learning framework with the aim to translate the unpredictable black box of Reinforcement Learning into classical flight control terminology. The framework is applied to a pitch rate command system of a jet aircraft and shows robustness to off-nominal flight conditions, center of gravity shifts and biased sensor noise. Accurate tracking performance is achieved, while adhering to Level 1 longitudinal Handling Qualities for all conditions.","Deep Reinforcement Learning; Intelligent Flight Control; Handling Qualities; Flight Control Systems; Machine Learning","en","master thesis","","","","","","","","","","","","Aerospace Engineering | Control & Simulation","",""
"uuid:f1ececbd-070f-415f-b4e5-3ea56bdc1731","http://resolver.tudelft.nl/uuid:f1ececbd-070f-415f-b4e5-3ea56bdc1731","Reversible allylic substitution based responsive polymer materials","Klemm, B. (TU Delft ChemE/Advanced Soft Matter)","Eelkema, R. (promotor); van Esch, J.H. (promotor); Delft University of Technology (degree granting institution)","2024","Signal transduction in living systems enables adaptive and interactive response to external stimuli. These rudimentary primary processes developed by nature are currently absent in synthetic materials. Implementing these processes in materials can have widespread advances in regenerative medicine, diagnostics or nanomachines. Taking inspiration from nature, organocatalytic reactions will be used in the design of new strategies for signal-responsive materials. These systems undergo physical or mechanical changes in response to stimuli triggered chemical transformations, enabling signal-recognition, signal- translation and ultimately leading to pre-programmed material response. In this thesis, small molecules, usually used as organocatalysts, are implemented in materials to develop signal-triggered and autonomous systems for applications such as controlled drug delivery, autonomous actuators or detection platforms...","","en","doctoral thesis","","978-94-6384-566-3","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:3a1b23b4-eb3a-413d-82dc-eeb402e75994","http://resolver.tudelft.nl/uuid:3a1b23b4-eb3a-413d-82dc-eeb402e75994","The use of green H2 and sustainable carburization to Fe3C for the direct reduction of iron ore pellets","van Leeuwen, Hugo (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Process and Energy)","Vlugt, T.J.H. (graduation committee); Moultos, O. (mentor); Dey, P. (graduation committee); Van den Broeke, L.J.P. (graduation committee); Delft University of Technology (degree granting institution)","2024","Steel manufacturing is a carbon intensive process, that is responsible for approximately 7% of the total global CO2 emissions. Therefore, TATA Steel IJmuiden aims to lower its carbon emissions. One way to bring down emissions, is to replace the existing blast furnace (BF) CO reduction process with the H2-based direct reduction of iron ore (DRI). The two most widely applied H2-DRI processes around the world are the low pressure MIDREX, abbreviated as MLP, and medium pressure HYL-Energiron, abbreviated as EMP. Since TATA Steel IJmuiden wants to study the switch from BF to H2-DRI steelmaking, it is relevant to gain insight into which gas phase reactions are dominant for both processes, into the direct reduction process itself and into the behaviour of the carburization reactions that improve the steel quality. In the gas phase reactions, it was seen that for the MLP process in situ reforming of natural gas can be a viable option before switching to a 100% H2 process. This may prove to be worthwhile in the early stages of H2-DRI steel production, when green H2 is still scarce and expensive. For EMP, internal reforming seems less of a possibility due to the high reaction rate for the reverse water gas-shift. When comparing both MLP and EMP, reaction rates are generally higher for EMP than for MLP and hence smaller reactor volumes are required for the EMP process to acquire the same amount of output. Direct reduction with H2 has a higher reaction rate than reduction with CO, while for the carburization reactions methane cracking was found to be the dominant reaction. Techno-economic scenarios for 100% H2-based DRI in which green H2 is imported are only feasible when H2-prices fall below €1.80/kg. Meanwhile, a scenario with an on-site electrolyzer powered by grey grid electricity only proves to be worthwhile for electricity prices lower than €20/MWh. The most promising techno-economic scenario, which includes an on-site electrolyzer and the construction of a wind farm just off the coast from the TATA Steel IJmuiden site, assumes an electricity price of €40/MWh.","Carburized steel; direct reduced iron; H2","en","master thesis","","","","","","","","","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:440a8782-1eff-441b-9816-601f6b4c6249","http://resolver.tudelft.nl/uuid:440a8782-1eff-441b-9816-601f6b4c6249","Weave-Inspired Digital Fabrication for Textile-Form","van der Laan, Femke (TU Delft Industrial Design Engineering)","Doubrovski, E.L. (mentor); McQuillan, H.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","This research explores the possibilities of combining additive manufacturing and weaving of textiles to create a novel textile-form. In recent years, additive manufacturing has revolutionized manufacturing processes by enabling the creation of complex three dimensional geometries with precision. Conversely, weaving, a traditional method of fabric production, offers inherent structural integrity and flexibility. However, recent research focusses on developing three dimensional textiles. By combining these two production methods, this research unlocks new opportunities for the production of composite textiles with enhanced properties and functionalities. During the FDM-printing process yarns were placed like a warp between two layers of filament. This basic principle of integrating these processes in explored in this research.
Throughout three design phases, the process was explored and further developed. Subsequently, the material underwent characterization through two rounds of testing. During the first tinkering phase, emphasis was placed on the connection points between the yarn and the filament. Achieving a connection between both materials heavily depended on the height of the nozzle. Various combinations of materials yielded samples with diverse behaviours, ranging from flowy to more elastic and springy textiles. All the samples exhibited anisotropic behaviour: along the x-axis, the material could plead like a textile, while along the y-axis, the filament provided rigidity, allowing the textile to form a dome. In the second phase, the emphasis shifted towards exploring forms by experimenting with various printing patterns. By implementing a zigzag pattern, an auxetic textile was successfully produced. When the samples were pulled along the x-axis, the material demonstrated the ability to open up in the z-direction. An experiential characterisation test was done by using the Ma2E4 toolkit, which conformed the curiosity and surprising qualities of the material. However, the material’s weakness and fragility posed limitations on the freedom to explore its potential fully. Interesting to find out was the contrast of interpretation between manufactured and handcrafted. During the third phase of tinkering, greater control over the auxetic behaviour of the material was achieved through experimentation with different densities and the implementation of cutting the yarns with a hot nozzle. Also the textileness was increased by using LW-PLA and adding noise to the print. For the technical characterization, a tensile test was conducted, revealing the clear anisotropy in the strength of the material. Additionally, the consistency in print quality was confirmed.
For this novel process and material, a variety of future applications could be envisioned. Ranging from utilizing the material’s movement in the z-direction for isolation to its ability to open up for light control. The process enables a seamless transition between a solid plastic and a textile, opening possibilities for applications such as shoes or chairs.
Patient-ventilator asynchrony (PVA) poses a significant challenge in the management of mechanically ventilated patients, contributing to adverse clinical outcomes. Current methods of detecting PVA rely on visual assessment by clinicians, leading to subjectivity and inconsistency. Therefore, there is a need for automated techniques to identify PVA accurately and efficiently. In this study, we explore the application of supervised and unsupervised machine learning algorithms to develop an automatic detection system for PVA.
Methods
This study was conducted at the ICU of the LUMC in Leiden, the Netherlands. Patients eligible for inclusion were mechanically ventilated with an esophageal balloon inserted. Data collected included flow, Paw, and Pes curves, which were labelled using an open-source data labeling platform and processed in Python. Supervised CNN models were trained for different ventilation modes, while unsupervised techniques, utilizing Mahalanobis distance, were explored for data pre-labeling. The discriminative capability of the models was assessed using AUROC values.
Results
25 patients were included in this study and labelled by clinicians. Using an unsupervised machine learning technique based on the Mahalanobis distance for data pre-labeling, a threshold of 3.5 was selected, resulting in a 95% accuracy in correctly identifying normal breaths. Creating different CNN models for automating the detection of PVA the results demonstrate the discriminative capability of the various models across all ventilation modes, PSV and PCV ventilation. They can differentiate between normal and abnormal breaths, as indicated by the AUROC values of 0.85(±0.08), 0.83 (±0.12), and 0.80 (±0.28) respectively.
Discussion
This study investigated the application of machine learning techniques to analyse ventilation data in critical care settings. Through a combination of unsupervised and supervised learning methods, we have explored the automation of the labelling process and the development of predictive models for identifying patient-ventilator asynchronies (PVAs).","Patient-ventilator asynchrony; Machine learning; Intensive Care Unit (ICU); Mechanical Ventilation","en","master thesis","","","","","","","","","","","","Technical Medicine | Sensing and Stimulation","TM30004; 35 ECTS",""
"uuid:bfd48eb9-5876-4924-b28a-b30e0d0c440c","http://resolver.tudelft.nl/uuid:bfd48eb9-5876-4924-b28a-b30e0d0c440c","Institutionalization of durable multi-stakeholder collaborations: An approach to stimulate durable collaboration in multi-stakeholder projects","Blom, Sjoerd (TU Delft Technology, Policy and Management)","Nikolic, I. (mentor); de Bruijne, M.L.C. (mentor); Delft University of Technology (degree granting institution)","2024","The Dutch energy landscape is becoming more complex due to various interacting factors and uncertainties, creating what are known as ""wicked problems"" that demand collaborative solutions. This study addresses knowledge gaps by developing a collaborative guide for fostering effective Multi-Stakeholder Collaborations (MSCs) that can endure over time. Through literature reviews and interviews, 69 factors influencing MSC durability were identified and organized using innovative clustering techniques, resulting in the collaborative guide. To test the effectiveness of this guide and develop recommendations to an existing MSC, the guide is applied to the MMvIB project as a case study using a structured four-step approach known as the COOP method. This method involves Consultation, Observation, Organization, and Perpetual development phases. By prioritizing influential factors and adapting to project dynamics, this approach aims to enhance the long-term success of MSCs. The insights and methods derived from this research are relevant to a wide range of collaborative contexts. Future research should focus on refining the approach and developing implementation strategies for these factors.","Multi-Stakeholder Collaboration; Collaborative guide; Approach; Durability; Clustering; COOP method","en","master thesis","","","","","","Double degree in Complex Systems Engineering and Management and Applied Physics","","","","","","Complex Systems Engineering and Management (CoSEM)","MMvIB",""
"uuid:78be5850-2df9-40fe-973d-e537d0d172c0","http://resolver.tudelft.nl/uuid:78be5850-2df9-40fe-973d-e537d0d172c0","Machine Learning-Induced Epistemic Injustice in Medicine and Healthcare","Pozzi, G. (TU Delft Ethics & Philosophy of Technology)","van den Hoven, M.J. (promotor); Duran, J.M. (copromotor); Delft University of Technology (degree granting institution)","2024","The advancement of AI-based technologies, such as machine learning (ML) systems, for implementation in healthcare is progressing rapidly. Since these systems are used to support healthcare professionals in crucial medical practices, their role in medical decision-making needs to be epistemologically and ethically assessed. However, a central issue at the intersection of the ethics and epistemology of ML has been largely neglected. This pertains to the careful scrutiny of how ML systems can degrade individuals’ epistemic standing as receivers and conveyors of knowledge and, thereby, perpetrate epistemic injustice. Since ML systems are powerful epistemic entities that are not easily contestable, and their decision-making rationale is often inaccessible, it is crucial to consider their role in creating imbalances in patients’ disfavor and the ways to mitigate such imbalances. This is especially important when it comes to interactions between patients and physicians, in which questions of credibility, trust, and understanding are central. Against this background, the overarching purpose of this dissertation is to fill this research gap by providing a framework to identify and, on occasion, mitigate epistemic injustices that are ML-induced, i.e., that emerge specifically due to the role that ML systems play in patient-physician interactions.","ethics of AI; epistemology of AI; machine learning-induced epistemic injustice; trustworthy AI; medical machine learning; automated hermeneutical appropriation","en","doctoral thesis","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:110bc70f-0e08-431d-bd41-00293f04ecee","http://resolver.tudelft.nl/uuid:110bc70f-0e08-431d-bd41-00293f04ecee","If it ain't broke, don't fix it: Optimizing the predictive aircraft maintenance schedule with Remaining Useful Life prognostics","de Pater, I.I. (TU Delft Air Transport & Operations)","Mulder, Max (promotor); Mitici, M.A. (copromotor); Delft University of Technology (degree granting institution)","2024","Predictive aircraft maintenance is a maintenance strategy that aims to reduce the number of failures, the number of inspections, the number of maintenance tasks and the aircraft maintenance costs. Aircraft are equipped with health monitoring systems, where sensors continuously measure the condition of the aircraft components. In predictive maintenance, these sensor measurements are used to estimate the time left until the failure of these components, called the Remaining Useful Life (RUL). These RUL prognostics are subsequently used to optimize the aircraft maintenance schedule. There are several challenges that complicate the implementation of predictive aircraft maintenance in practice. In this thesis, the threemain challenges are addressed.","Predictive maintenance; Remaining Useful Life prognostics; Aircraft maintenance","en","doctoral thesis","","","","","","","","","","","Air Transport & Operations","","",""
"uuid:2f2dfc76-5e29-4a04-84c1-3d337e3bf645","http://resolver.tudelft.nl/uuid:2f2dfc76-5e29-4a04-84c1-3d337e3bf645","Engineering Synthetic Cells through Module Integration and Evolution","Restrepo Sierra, A.M. (TU Delft BN/Gijsje Koenderink Lab; TU Delft BN/Christophe Danelon Lab)","Danelon, C.J.A. (promotor); Koenderink, G.H. (promotor); Delft University of Technology (degree granting institution)","2024","Life, the most complex and admirable machine that one could think of has evolved over billions of years to display a beautiful variety of mechanisms that keep cells adapting, self-maintaining, reproducing, and evolving. If we think about it, what is this magic? What are the mechanisms behind life’s origins and wonderful coordination? Attracted by these intricates, different scientific disciplines have for long studied all life’s scales to grasp the fundamental principles of life. In particular, the synthetic biology field has set the goal of discerning life until the point that a minimal synthetic cell can be fully recreated in a controlled laboratory set-up. Synthetic cells, modular enough to be crafted by scientists, could not only reveal fundamental insights of how life works, but can also help unlock great biotechnological applications that lie beyond the reach of our current technologies and understanding of life. In this thesis, we delve into how in vitro evolution, module integration, and high throughput characterization are valuable steps to consider for accelerating the bottom-up assembly of artificial cells.","synthetic biology; synthetic cell; liposomes; cell-free gene expression; module integration; DNA replication; phospholipid biosynthesis; in vitro evolution","en","doctoral thesis","","978-94-6384-563-2","","","","","","","","","BN/Gijsje Koenderink Lab","","",""
"uuid:3b374980-4c24-48f2-9c7b-755eefbef636","http://resolver.tudelft.nl/uuid:3b374980-4c24-48f2-9c7b-755eefbef636","Optical alignment strategies for assembly of endoscopic probes","de Vries, Barbara (TU Delft Mechanical Engineering; TU Delft Applied Sciences)","Tichem, M. (mentor); Iskander-Rizk, Sophinese (mentor); Delft University of Technology (degree granting institution)","2024","Reliable assembly methods are needed to translate new endoscopic probes from the research phase to clinical testing. Design variation complicates standardized assembly and leads to a lengthy process creating inaccurate prototypes, preventing repeatable research. This thesis proposes a strategy for selecting the most effective assembly method by examining alignment and bonding relations among parts. Considering the manufacturing tolerances of the optical parts leading to a loss of image quality, an approach for testing is selected to align the gradient index (GRIN) lens and fibre. This approach implements an active alignment procedure and reaches a sensitivity of 3 for the concentricity, 0.4 deg for the colinearity and 40 for the separation distance. These results validate a better result than reachable with passive alignment. An optimization algorithm could replace the manual comparison of the ideal beam profile for increased repeatability. To advance the research to the assembly of complete prototypes, more components of the probes should be added to the investigation and a method for fixing the components to the housing should be introduced.","Endoscopic instrument; Probe; assembly","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Optomechatronics","",""
"uuid:ab56fd5e-d4d1-4276-894c-8cba3a1b76bc","http://resolver.tudelft.nl/uuid:ab56fd5e-d4d1-4276-894c-8cba3a1b76bc","Prediction of Crashworthiness Performance Using Multi-Fidelity Machine Learning Techniques","Koronaios, Panagiotis (TU Delft Aerospace Engineering)","Castro, Saullo G.P. (mentor); Maathuis, H.F. (mentor); Delft University of Technology (degree granting institution)","2024","This study investigates the development and application of meta-models for crashworthiness assessment of helicopter structures and components. It aims to address the challenges associated with scarcity of data from computationally expensive simulations and experimental drop-tests, and enable the use of surrogates in a crashworthiness optimization framework. Two predictive approaches utilizing Machine Learning techniques are compared to predict and assess the energy absorption of tubular metallic structures for different cross-section configurations. The first approach directly predicts energy absorption, while the second predicts load-displacement curves, from which energy absorption is derived. Results indicate that certain regressors, such as the Transform Target Regressor, the Decision Tree Regressor and the Poisson Regressor, consistently achieve high accuracy in predicting load-displacement curves and energy absorption across the evaluated tubular samples. A low-fidelity model able to provide less accurate but computationally inexpensive information is then introduced. The influence of low-fidelity data is investigated when it serves as additional input alongside high-fidelity data during the training phase of the surrogate model, through a comparative analysis. The research's findings suggest the efficiency of Machine Learning in representing structural behaviour under crushing conditions and highlight the potential for further enhancements through the integration of low-fidelity data, thereby holding promise for extending the methodology to more complex structures.","Crashworthiness; Machine Learning; Surrogate Modeling; Multi-fidelity","en","master thesis","","","","","","","","2024-09-30","","","","Aerospace Engineering","",""
"uuid:1f71feeb-4aeb-4795-b8d3-c41c83f733cd","http://resolver.tudelft.nl/uuid:1f71feeb-4aeb-4795-b8d3-c41c83f733cd","Design for sustainable fashion: 3D weaving for denim jeans production","Groskamp, Jordan (TU Delft Industrial Design Engineering; TU Delft Sustainable Design Engineering)","McQuillan, H.L. (mentor); Voorwinden, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","The fashion industry is facing complex environmental challenges, and a need for change is prevalent for the industry to move towards circular economies. 3D weaving emerges as an innovative approach to garment design and production, allowing for novel processes that capture the opportunities missed by current linear systems. 3D weaving of integrated multilayer Jacquard fabrics for denim garments shows potential for increased efficiency, reduced environmental impact, new design avenues and unprecedented levels of automation in future processes.
This project sets out to research the practical application of 3D weaving for the sustainable design and production of denim garments. It explores the opportunities, limitations and execution of 3D weaving for creating a pair of 5-pocket denim jeans in existing supply chains (production samples provided by Diamond Denim). This report of the process acts as a practical guide for further adoption of 3D woven denim in academia and the industry. A production prototype is developed to showcase the benefits of 3D weaving for denim design and production, while also evaluating the implications of this particular zero waste design for 3D weaving and the industry as a whole.
Evaluation of the design results suggest that this application of 3D weaving could potentially: Reduce stitch length by 40%, reduce pre-consumer waste by 20%, reduce water usage by 25%, eliminate use of micro plastics and become 100% recyclable. Further improvements are expected when the technology finds further adoption in the industry. A majority of industry respondents (n16) expressed interest in the technology, estimating that commercial application is feasible within the next 3-5 years with a production price increase that does not exceed 25% compared to conventional denim jeans. Further potential lies in tackling online returns, overstockage, made on demand systems, user customization and further optimization of the technology for increased efficiency and reduced cost.
Overall, 3D weaving presents itself as a new fundamental tool in sustainable fashion design, one that requires new levels of expertise and industry alignment. Further, while future research and development helps to overcome limitations in the process of 3D weaving, the proof of concept presented in this report concludes that this process can already be done with existing machinery.
Innovations such as 3D weaving may find resistance while gaining wider adoption as their implications require a major shift in current processes, often straying away from common practices that feel safer from an economic perspective. Mitigating some of the risk through development in academic settings may help to persuade businesses to adapt pivotal methods like 3D weaving sooner, as the groundwork has already been done. This underscores the need for academic research through projects focussing on sustainable design and innovation.
In 2022, Aalberts Hydronic Flow Control introduced a total of 2739 tons of (registered) packaging to the market. This included 1807 tons of cardboard, 155 tons of plastic, and 777 tons of wooden packaging. The thesis focuses on the product categories PEX pipe, Expansion Vessels, Valves and Fittings that contribute most significant to packaging at Aalberts (54% of total packaging), representing 92 tons of plastic (59.4% of all plastic packaging), 872 tons of cardboard (48.3% of all cardboard packaging) and 520 tons of wood packaging (66.9% of all wood packaging).
Based on, among others, findings from literature research, expert interviews, interviews with Aalberts’ employees, competitor analysis, research into regulations, business economics and market trends, a strategic roadmap is designed showing all recommended actions for
Aalberts to achieve packaging reduction based on three periods:
- The first period (now-2025) is focused on the implementation of most financially appealing packaging changes for Aalberts to reach the target of 20% reduction by 2025. Investments are needed, but are expected to be profitable within 2 years of implementation, leading to
20.7% reduction of all packaging (566 tons).
- The second period (2025-2035) is focused on reducing unnecessary packaging and redesigning packaging for recycled and less material use. In this period investments are needed to reduce packaging, contributing to more packaging reduction at Aalberts, leading
to an accumulative reduction (of period I & II) of 25.8% of all packaging (707 tons).
- The third period (>2035) aims at eliminating single-use packaging through implementing the concept of packaging as a product. This requires further investments and a bigger change in packaging practices than the two periods before, which eliminates single-use packaging
completely, leading to an accumulative reduction (of all periods) of 54.2% reduction of all packaging (1484 tons).
In order to reach the target of 20% reduction by 2025, investment based packaging changes need to be made. Most financially appealing actions that are recommended to be implemented before 2025 are the following:
1. Reduce bag sizes Valves and Fittings by 50%
Reducing unnecessary packaging saves the company material and costs, a win-win scenario for Aalberts. It is advised to start with the reduction of plastic bag sizes for Valves and Fittings (46 tons, 1.7% of all packaging at Aalberts) since this provides the largest
packaging reduction of unnecessary packaging.
2. Reusable pallets PEX pipe
Changing to reusable pallets for PEX pipe provides the largest reduction in packaging material with 520 tons (19% of all packaging at Aalberts). This change does require a one-time investment of €385,000 but saves €200,000 per year on single-use pallets. Therefore return
on investment will be within 2 years. Since the packaging change offers a large reduction (close to the target of 20%) and saves costs in the long term, this action is recommended to be implemented as soon as possible to reach the target before 2025 (together with reducing bag
sizes for Valves and Fittings).
Due to upcoming regulations on packaging, goals of Aalberts and the European Union to become net-zero by 2050, the following new targets are advised:
- Reduce all single-use plastics by 100% by 2040
- Reduce all single-use packaging by 100% by 2050
The new targets could be achieved with the concept presented in the third period of the strategic roadmap: packaging as a product. This concept aims to eliminate single-use packaging completely through redesigning packaging to replace another product by providing packaging
with an additional function.","Circular Economy; packaging design; Roadmap; Sustainability; Packaging waste","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:c36895aa-3fe3-4049-ba92-f2ed6d4bcfad","http://resolver.tudelft.nl/uuid:c36895aa-3fe3-4049-ba92-f2ed6d4bcfad","Innovative approach to repetitive tasks: An exploratory research on exploiting the potential of repetitive tasks in the construction industry","Smit, Heleen (TU Delft Civil Engineering & Geosciences)","Hermans, M.H. (graduation committee); Molaei, M. (mentor); Bosch-Rekveldt, M.G.C. (graduation committee); de Lange, Huub (graduation committee); Delft University of Technology (degree granting institution)","2024","Current societal and construction challenges, combined with limited time and the scarcity of people and resources, require solutions in the construction industry. This research focuses on repetitive tasks and contributes to that. Furthermore, this research is necessary because the literature on repetitive tasks is limited and needs to be supplemented. The research objective was to increase the understanding and knowledge of the design elements aimed at exploiting the potential of repetitive tasks in assignments where public clients and contractors collaborate. Based on the literature review, repetitive tasks and associated potential were defined and a theoretical framework was established. The empirical research consists of studying three cases, the programmes WL, IPS Schoolgebouwen and WOUW, using case documents and eighteen interviews conducted with public clients and contractors. This provided a picture of repetitive tasks in different construction sectors (residential, utility and infrastructure construction) and at different phases of the asset life cycle (new construction, maintenance and renovation). Separate analysis of the three cases, combined with cross case analysis and the established theoretical framework, then formed the basis for the ""Innovative approach to repetitive tasks"" framework. Through an ""innovative approach to repetitive tasks"", consisting of a cross-project inventory of repetitive tasks and the application of the design elements and advices proposed in the “Innovative approach to repetitive tasks” framework, the forces of the public client and the contractors are combined and the potential of repetitive tasks is unlocked.","Repetitive tasks; Potential of repetitive tasks; Public client; Contractor; Collaboration; Construction industry; Programme","en","master thesis","","","","","","","","2025-05-01","","","","Civil Engineering | Construction Management and Engineering","Innovative approach to inter-organisational collaboration in repetitive activities",""
"uuid:68aff3d8-4447-41b1-ad09-b26072b63a62","http://resolver.tudelft.nl/uuid:68aff3d8-4447-41b1-ad09-b26072b63a62","Manufacturing Laminate-Free PV Modules at Large Scale","Pacifico, Antonio (TU Delft Electrical Engineering, Mathematics and Computer Science)","Manganiello, P. (mentor); Balkenende, R. (graduation committee); Brinksma, Siemen (mentor); Delft University of Technology (degree granting institution)","2024","As photovoltaic (PV) technology enters the terawatt era, reliability, sustainability, and circularity in the solar industry can no longer be optional considerations for manufacturing solar modules. Despite two decades of intense solar manufacturing, the PV industry still predominantly operates within a linear economic structure, characterized by energy-intensive production and limited sustainability practices. One significant challenge associated with crystalline PV modules is the encapsulation process, which occurs within costly and unwieldy laminator machines. While laminating PV modules offers long-term stability and performance, it also imposes significant limitations on the disassembly, repairability, and recyclability of valuable PV module materials. The development of sustainable PV designs and manufacturing processes is crucial for transitioning to a circular economy. In response to this problem, Biosphere Solar, a startup company based in Delft, is developing a novel solar module design that eliminates the need for lamination. Their focus is on creating an easily disassembled solar module to facilitate repair, reuse, and ultimately achieving full recyclability with low-energy input. It is crucial to recognize that transitioning to non-laminated modules presents challenges in manufacturing. This thesis aims to identify and address barriers encountered in manufacturing laminate-free PV modules compared to traditional PV panels. First, becoming acquainted with laminated PV lines provided insights into the challenges to be encountered. The analysis of the laminate-free product primarily examines the module components, and materials diverging from laminated panels, such as adhesives, solder pastes, fillers, and edge sealants, assessing their trade-offs and configurations in terms of manufacturability. The product analysis has facilitated the definition of a manufacturing process flow, which is constructed based on assembly operations that both align with and diverge from standard PV manufacturing practices. This is complemented by an exploration of non-standardized processing methods, considering the associated boundary conditions in the assembly. The main challenges encountered include the metal paste dispensing, low-temperature soldering, and fluid filling processes, with multiple units installed and a necessity for a specific design tailored to this application. This study demonstrates competitiveness with respect to laminate PV line scales, particularly evident in larger-scale operations. Technically, a 30% reduction in energy consumption for machinery and up to 50% factory area savings can be achieved. The electrical consumption of the laminator(s) alone, for production volumes up to 300MW, can range between 20% and 50%, with a footprint share of up to 10% of the total manufacturing space. Economically, capital costs also demonstrate promise and have the potential to outperform laminated PV modules, especially in a highly automated setup line. Savings between 20-30% for equipment costs and up to 50% for building infrastructure costs are achievable. Nevertheless, the main factors offsetting these mitigated capital costs are the operational expenses associated with the bill of materials and the manpower required to produce this specific product. These material expenses can be up to 4-5 times higher than for a laminated panel, and up to twice the investment in manufacturing labour. This assessment lays the foundation for future research leveraging the trade-offs explored to refine choices and achieve optimal results.","laminate-free PV module; non-standard PV manufacturing; sustainable PV; circular solar modules","en","master thesis","","","","","","","","","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:36db9caa-5cef-4f35-8b12-dad753d6e81c","http://resolver.tudelft.nl/uuid:36db9caa-5cef-4f35-8b12-dad753d6e81c","Market Structures and Coordination Issues in Passenger Rail Markets: A study on policy decision-making for passenger rail transport in The Netherlands","Godeke, Tijmen (TU Delft Civil Engineering & Geosciences; TU Delft Technology, Policy and Management)","Veeneman, Wijnand (mentor); Cats, O. (graduation committee); Roelofsen, D.S. (mentor); Delft University of Technology (degree granting institution)","2024","This thesis aims to contribute to the policy debate on the complexity of passenger rail markets and to provide recommendations for the Dutch market. An extensive literature review has been conducted to identify the policy issues that must be discussed when dealing with passenger rail markets. These issues are structured in a theoretical framework to describe market structures and understand market complexity. The framework classifies the policy issues into three levels of decision-making, influenced by causal factors and resulting in system performance measured by three categories of indicators. The approach to passenger rail market analysis proposed in this thesis can be useful for researchers and policymakers to assess passenger rail markets in a structured way. The relevance of the policy issues was identified through a Delphi study involving 13 experts and stakeholders. As a result of the study, the role of different levels of government in market coordination, coordination of investments, timetables and incidents, and the level of transition costs were identified as key policy issues. An analysis of the Dutch market resulted in a recommendation to continue direct award to Nederlandse Spoorwegen on the main rail network. However, it is also recommended that Dutch policymakers prepare for the introduction of competition to strengthen their coordinating role and be ready for the eventuality of competition.","passenger rail; decision making; markets; coordination","en","master thesis","","","","","","","","","","","","Transport, Infrastructure and Logistics","",""
"uuid:464b0d6e-cad0-4be2-8fc1-253568bb8292","http://resolver.tudelft.nl/uuid:464b0d6e-cad0-4be2-8fc1-253568bb8292","Improving the Replacement and Renovation Process of Hydraulic Structures: Creating a decision method for the implementation and assessment of standardisation","Kolk, Iris (TU Delft Civil Engineering & Geosciences)","Voorendt, M.Z. (mentor); Houwing, E.J. (graduation committee); Versluis, Marco (graduation committee); Delft University of Technology (degree granting institution)","2024","This study develops a decision method for the implementation and assessment of standardisation in order to improve the Replacement & Renovation process of hydraulic structures. Possible improvements in the Replacement & Renovation process and the implementation of standardisation were identified by conducting semi-structured interviews. A general decision method results from combining the identified improvement points and the basic design principle. This general decision method is further developed by describing the required steps, decisions, input, and generated output. This decision method is a starting point for asset management organisations that want to start with implementing standardisation into the Replacement & Renovation process. A potential benefit of using the decision method is increased efficiency of the design process, as a learning curve is expected, saving time and money. Furthermore, the results can be used for an in-depth discussion about the feasibility of standardisation in the considered management area.","Standardisation; Replacement & Renovation; hydraulic structures; Decision Making Tool; Asset Management","en","master thesis","","","","","","","","","","","","Civil Engineering | Hydraulic Engineering","",""
"uuid:9037207d-c92a-43c0-a4ea-41907b4f4d14","http://resolver.tudelft.nl/uuid:9037207d-c92a-43c0-a4ea-41907b4f4d14","Green AI in Action: Strategic Model Selection for Ensembles in Production","Nijkamp, Nienke (TU Delft Electrical Engineering, Mathematics and Computer Science)","van Deursen, A. (mentor); Sallou, J. (mentor); Cruz, Luis (mentor); van der Heijden, Niels (mentor); Delft University of Technology (degree granting institution)","2024","Integrating Artificial Intelligence (AI) into software systems has significantly enhanced their capabilities while escalating energy demands. Ensemble learning, combining predictions from multiple models to form a single prediction, intensifies this problem due to cumulative energy consumption.
This paper presents a novel approach to model selection that addresses the challenge of balancing the accuracy of AI models with their energy consumption in a live AI ensemble system. We explore how reducing the number of models or improving the efficiency of model usage within an ensemble during inference can reduce energy demands without substantially sacrificing accuracy.
This study introduces and evaluates two model selection strategies, Static and Dynamic, for optimizing ensemble learning systems' performance while minimizing energy usage. Our results demonstrate that the Static strategy improves the F1 score beyond the baseline, reducing average energy usage from 100% from the full ensemble to 62%.
The Dynamic strategy further enhances F1 scores, while using on average 76% compared to 100% of the full ensemble.
Moreover, we propose an approach that balances accuracy with resource consumption, significantly reducing energy usage without substantially impacting accuracy. This method decreased the average energy usage of the Static strategy from approximately 62% to 14%, and for the Dynamic strategy, from around 76% to 57%.
Our field study of Green AI using an operational AI system developed by a large professional services provider shows the practical applicability of adopting energy-conscious model selection strategies in live production environments.","","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:0d11370c-31ff-437a-9680-6ee5b1cf05bb","http://resolver.tudelft.nl/uuid:0d11370c-31ff-437a-9680-6ee5b1cf05bb","Far-field plume dispersion modelling for backhoe dredging activities in the Black Rocks harbour","van der Voorn, Jesper (TU Delft Civil Engineering & Geosciences; TU Delft Hydraulic Engineering)","van Koningsveld, M. (mentor); Antolínez, José A. Á. (mentor); Ruijter, M.N. (mentor); van der Plas, A.F. (mentor); Delft University of Technology (degree granting institution)","2024","On Saba, an island located in the Caribbean, a new harbour will be constructed. To protect coral reefs in the vicinity from light attenuation and sedimentation, it is important to monitor and predict the turbidity stresses caused by the dredging operation. In the early stages of such projects involving dredging operations, a common approach is to estimate the turbidity stresses in a simplified way using stationary source terms and the exclusion of important physical processes as tidal and wind-forcing. This research focused on the development of a representative approach to simulate the turbidity effects from dredging activities by backhoe dredgers in the vicinity of Caribbean islands, by building on existing methods by Becker et al. (2015) and Tuinhof (2014). The Black Rocks harbour project on Saba was used as a case study to test the effectiveness of the new method approach.
First, the local physical processes were identified and their influence on the turbidity stresses and dispersion of the sediment plumes were discussed. Insight in the wave heights and wave period should be obtained to aid in the decision for the dredging equipment to use and their workability. Key processes to include for a representative simulation for the dispersion of the plumes were identified to be the tidal and wind driven currents over the depth. Another local phenomenon to consider was the run-off from peak precipitation events, as this results in high background turbidity levels. Analysis of local sediment samples is required to obtain insight in the fines content, required for the estimation of the sediment flux, and the distribution of particle sizes and the particle density to determine the settling velocity.
Insight in the work method and duration of the dredging cycle provides information to determine the temporal distribution of the source terms to suitably simulate the loss of fines over time, making a distinction for the presence of the source between day and night cycles and during relocation. The primary source term contributing to the release of fines, identified to be the bucket drip, was spatially distributed to simulate the relocation of the backhoe. An additional method step was introduced by estimating the local fines content for each source term over the dredging volume, resulting in a more representative approach for dredging volumes exhibiting a heterogeneous distribution of the fines content compared to using a single value for the fines content. The source terms were estimated using an existing method by Becker et al. (2015) and distributed over multiple sediment fractions, to include the representation of the smaller particles, affecting the
far-field SSC in the model.
The effects of tidal and wind-forcing were incorporated using a 3D model, while running different hydrodynamic scenarios to test the effects for a variety of flow conditions. The grid resolution was chosen to ensure an accurate representation of the spatial distribution of the sediment concentration resulting from the bucket drip. The source terms were equally distributed over the depth to simulate the gradual loss of the fines over the depth by the bucket drip. The selection of an appropriate formulation for the settling velocity, to account for the local hydrodynamic conditions and sediment characteristics, increases the representation of the distribution of fines over time.
The model results indicated that for both a stationary and relocating source term, an accurate
depiction of the average SSC values over longer time periods as days and weeks is simulated, while the relocating source tends to estimate peak concentrations more accurately, as the source location and quantity is represented more precisely. Turbidity thresholds, set for the Black Rocks project, were only exceeded on one occasion during the occurrence of a current reversal for the relocating source, but not for a stationary source. This indicates the added value of applying a more detailed approach to simulate the turbidity stresses. Following the suggested additions to the methods an updated approach to simulate the turbidity stresses by a backhoe dredger was proposed. Further research into refinement of the method, focusing on the spatial distribution of the source and appropriate spatial and vertical grid resolution, can increase the suitability of the suggested method for simulating turbidity stresses induced by a backhoe dredger.","Dredging; Plume modelling; Saba; Delft3D FM","en","master thesis","","","","","","","","","","","","Civil Engineering | Hydraulic Engineering","",""
"uuid:5c78d9fe-76f5-41b4-8d17-70de3e0d2ef3","http://resolver.tudelft.nl/uuid:5c78d9fe-76f5-41b4-8d17-70de3e0d2ef3","Mediventic Smart Shirt: Knitted Breathing Sensors for Medical Wearables","Duyts, Sybe (TU Delft Industrial Design Engineering)","Jansen, K.M.B. (mentor); Karlsson, K.F. (graduation committee); Delft University of Technology (degree granting institution)","2024","This project focuses on developing a functional wearable prototype that can monitor changes in breathing behaviour by integrating textile sensors. The project was initiated by Mediventic, a healthcare industry start-up aiming to simplify the diagnoses and treatment of Chronic Hyperventilation Syndrome (CHVS) by creating affordable home-use smart clothing embedded with sensors that objectively record a patient’s biomedical data. Medical literature highlights the challenges of accurately diagnosing medical conditions in the healthcare industry, particularly CHVS, which is prone to errors due to the unusual range of complaints and symptoms. Medical professionals underline the need for wearable instruments to detect tell-tale signs and provide preventative treatment. On the other hand, current applications of smart textile wearables often lack focus on a specific problem.
To better comprehend the problem and solution space, fundamental medical themes and the current status of wearable technology are reviewed. Important annotations about CHVS are concluded, emphasizing the close link between psychological and physiological elements that drive the self-perpetuating cycle of chronic hyperventilation and the development of symptoms. To assist the patient in gaining respiratory control, the use of wearable technology to support treatment processes is investigated. In particular, ‘smart textiles’ resemble an attractive medium for the integration of sensors and electronics. Respiratory movements can be captured at various points on the upper body utilizing strain sensors embedded in the textile medium. This allows a wearable to preserve valuable qualities for
user experience typical for textiles such as comfort, flexibility, and aesthetics.
During prototype development, performance, manufacturability, and usability requirements are translated into tangible prototypes, such as the fabrication of working knitted strain sensors for tracking breathing behaviour. Different versions are fabricated through iterative steps and intermittently tested for performance and usability. Throughout development, the steps for fabricating and integrating components as a ‘textile system’ are made insightful. Through user testing, the final prototype is used to evaluate sensor performance and as well assess for comfort and usability. Participants are instructed to wear the prototype in several active positions and perform breathing tests.
Conclusively, the results and development process are contemplated concerning the project’s design requirements and initial aim. Although the data’s usefulness must be evaluated by medical professionals, the results suggest that utilizing knitted sensors for measuring breathing behaviour is successful enough for real-time data collecting, even with basic prototyping components. Information regarding breathing rate and depth of respiration can be interpreted at different locations on the body. Also, the prototype design appeals to the imagination during user tests. Users associate the prototype with regular clothing and results indicate that the wearable-textile form factor allows for unintrusive monitoring of breathing behaviour. However, developments must be made to improve the reliability of the construction and durability of the sensors. Depending on the definition of signal detail, signal amplification and noise suppression might elevate the quality of information to the next
level.","Wearable Technology; Knitting; Strain Sensor Applications; Medical design; Breathing detection","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:44ec063a-5788-4ecb-9bd7-d531bda32742","http://resolver.tudelft.nl/uuid:44ec063a-5788-4ecb-9bd7-d531bda32742","Defining good public participation processes under the Environment and Planning Act: Perspectives from stakeholders","Kalb, Annelotte (TU Delft Civil Engineering & Geosciences)","Kroesen, M. (mentor); Hobma, Fred (graduation committee); Leijten, M. (graduation committee); Oztürk, Kübra (graduation committee); Verboom, Linda (graduation committee); Delft University of Technology (degree granting institution)","2024","On January 1st 2024, the Environment and Planning Act (EPA) took effect in the Netherlands. This legislation aims to simplify existing environmental legislation for spatial projects by combining them into one. An important pillar of the EPA, specifically of the environmental permit, is public participation. However, the safeguarding of this in the law is limited since its organization is not regulated. In general, the methods for involving the public in environmental decision-making remain contentious, which has previously led to research into principles that define good public participation processes. The majority of the literature assumes that all parties involved in a process share the same principles, while it may be the case that stakeholders hold differing views on what constitutes a good process. In the EPA, a conscious choice was made to prohibit municipalities from imposing requirements on initiators on how they implement participation, the reason for this being enabling local customization. Yet, this uncertainty regarding the best practices for public participation can make it difficult for an initiator to set up participation for their project. This research aimed to gain insight into what constitutes a good public participation process by determining if and how stakeholders characterize this differently, specifically for real estate construction in residential areas. Therefore, the research question was as follows: What perspectives exist on what constitutes a good public participation process for real estate construction projects in residential areas and what characterizes the stakeholders within these perspectives?
Q-methodology was used to extract stakeholders' views on successful participation from the results of a survey. This resulted in the identification of four perspectives, representing four different collective views on good participation shared by several stakeholders. Perspective one, a trusted process leading to influence by the right people, considers participation to be good if trust is created and the input provided actually influences the initiative. The second perspective, a clearly defined process resulting in greater support, has a positive opinion about participation as long as the organized process is very clear, professional, and properly followed, and results in greater support for the initiative. The third perspective, achieving satisfaction with a tailor-made process, believes that participation is good if the process is situation-specific, followed well and there is satisfaction with how it went down, regardless of whether it resulted in adjustments to the design of the initiative. Lastly, perspective four, as long as everyone is heard, feels that participation is good when the design of the initiative is changed according to the input provided by participants who were involved from the start and whose expertise is valued. After the identification of these perspectives, it was investigated whether a relationship could be observed between a stakeholder's characteristic and their perspective. Here, it was observed that civil servants relatively adhere to perspective three more than the other groups.
This research has provided new scientific insights by showing that there are different views on what constitutes 'good' public participation. These perspectives have unique aspects but they also have some similarities. It is recommended that project initiators incorporate important aspects of all four perspectives when designing a participation process for an initiative, to ensure that it is as 'good' as possible. To aid initiators in doing so, a one-pager has been drafted which contains an overview of the important aspects of each of the perspectives. With this, the practical aim of the research - which was to provide support to project initiators for the setup of participation processes - was achieved.","Environment and Planning Act; environmental permit; public participation; real estate construction; Q-methodology","en","master thesis","","","","","","","","","","","","Civil Engineering | Construction Management and Engineering","",""
"uuid:b24f80ba-8c4d-4203-aaff-8289cffbff74","http://resolver.tudelft.nl/uuid:b24f80ba-8c4d-4203-aaff-8289cffbff74","Sustainable Design Development of a Concrete Lock Chamber: Reaching a Sustainable and Durable Design of a Ship Lock Concrete Hard Structure, Enabling Navigation Through the Haringvliet Storm Surge Barrier as Part of the Delta21 Project","Hjörvarsdóttir, Soley (TU Delft Civil Engineering & Geosciences; TU Delft Old - CITG Dept. Structural and Building Engineering)","Hendriks, M.A.N. (mentor); Jonkers, H.M. (graduation committee); Molenaar, W.F. (graduation committee); Poliotti, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Concrete is the second most used material in the world after water and recent trends show no slowing down of the concrete use around the world. Concrete is also a huge contributor to CO2 emissions as it makes up 8% of emissions. This study investigates the optimization of concrete structures to reduce environmental impact while maintaining structural integrity and cost-effectiveness, e.g. how to make a concrete structure more sustainable. A previous report where quay wall designs of different materials were compared in regard to the CO2-emissions and life cycle assessment found that a concrete quay wall had 43% more emissions than a steel quay wall. The goal of this study is to reduce the overall CO2 equivalent emissions related to a concrete structure by 50% and make the design more sustainable.
A concrete ship lock chamber as part of the Delta21 project is used as a case study. To measure the positive effect of sustainability two chambers are designed; a base case chamber designed based on what is most commonly done in practice in the structural engineering field, and an alternative chamber design with the aim of making the concrete lock chamber more sustainable. A partial life cycle assessment (LCA) is performed on both of the two design alternatives. The optimization of the alternative chamber design focused on minimizing global warming potential (GWP) by adjusting the reinforcement-to-concrete ratio and incorporating structural elements such as plated steel anchors. The two alternatives are analysed comparably as they are designed under the exact same conditions, in the same environment and with the same functionality aspects.
The base case structure is a U-basin concrete chamber with tapered walls. The alternative optimised structure enhances the structural behaviour of the chamber wall by adding anchors. This reduces the moments by 88% and the shear force by 56% compared to the base case design. By changing the structural wall type in the chamber by adding anchors, the concrete volume could be reduced by 47% between the base case design and the optimised design. This also allows for a reduction of concrete strength class, reinforcement volume, underwater concrete floor thickness and the number of tension piles for the construction pit. The LCA reveals a 55% reduction in the GWP for the alternative concrete chamber design, compared to the base case design. An optimum reinforcement ratio for the alternative concrete chamber anchored wall of 2.3% is identified, resulting in a balance between structural performance and environmental sustainability without increasing material costs. This ratio doesn’t incorporate labour cost which might affect this optimum ratio by lowering it. This demonstrates the potential for achieving environmentally responsible solutions without compromising the structural integrity of a structure or incurring additional costs.
The study highlights the potential for integrating sustainability objectives into concrete structure design, with recommendations for further research including exploring alternative materials and advanced optimization techniques.","Concrete structures; concrete; sustainability; LCA; hydraulic structures; ship lock","en","master thesis","","","","","","","","","","","","Civil Engineering | Hydraulic Engineering","DELTA21",""
"uuid:239cbb59-90d6-49b9-9dc5-ea6addb3d6e1","http://resolver.tudelft.nl/uuid:239cbb59-90d6-49b9-9dc5-ea6addb3d6e1","Homeostasis in intestinal organoids at the single cell level","Kok, R.N.U. (TU Delft BN/Sander Tans Lab)","Tans, S.J. (promotor); Ten Wolde, Pieter Rein (copromotor); Delft University of Technology (degree granting institution)","2024","How does the small intestine maintain itself? What mechanism does it use to achieve
homeostasis, and how optimal is this mechanism? We approached these questions
mainly using cell tracking in organoids, for which we developed new cell trackers.
We found that the intestinal crypt uses a surprisingly simple and effective strategy.
Finally, we showed that cell segmentation and tracking is possible in organoids without fluorescent markers.","organoids; small intestine; homeostasis; cell tracking","en","doctoral thesis","","","","","","","","","","","BN/Sander Tans Lab","","",""
"uuid:4423b7e9-caff-46b3-9185-339d65a5b8c1","http://resolver.tudelft.nl/uuid:4423b7e9-caff-46b3-9185-339d65a5b8c1","On Non-Stationarity in Reinforced Deep Markov Models with Applications in Portfolio Optimization","Chin-A-Pauw, Laurens (TU Delft Electrical Engineering, Mathematics and Computer Science)","Yu, F. (mentor); Papapantoleon, A. (graduation committee); Derumigny, Alexis (graduation committee); Delft University of Technology (degree granting institution)","2024","In this thesis, we aim to improve the application of deep reinforcement learning in portfo- lio optimization. Reinforcement learning has in recent years been applied to a wide range of problems, from games to control systems in the physical world and also to finance. While reinforcement learning has shown success in simulated environments (e.g. matching or exceeding human performance in games), its adoption in practical applications (non- simulated environments) has lagged. Dulac-Arnold et al. [2019] suggest this is caused by a discrepancy in the experimental set-up in research and the conditions in practice. Specifically, they present a list of challenges that make the application of reinforcement learning in real-world settings more difficult. One of these challenges is non-stationary environments, which is common in financial environments. It is a challenge since, given an observed state, the optimal action may not always be the same as it may change over time due to non-stationarity. Therefore, more specifically, the goal of this thesis is to overcome the challenge of non-stationarity in the application of reinforcement learning to portfolio optimization. In this thesis, we use reinforced deep Markov models (RDMM) introduced by Ferreira [2020] (applied to an optimal execution problem and later used by Cartea et al. [2021] for statistical arbitrage on simulated price movements of an FX triplet) for its data efficiency and ability to handle complex environments. RDMM involve a partially observ- able Markov decision process (POMDP) which is also the setting used by Xie et al. [2021] to model non-stationarity in reinforcement learning. We extend RDMM to incorporate non-stationarity, using the framework suggested by Xie et al. [2021], and apply it to port- folio optimization. Our implementation is sample efficient which allows for quick learning, by doing this we attempt to improve on another challenge of reinforcement learning — i.e. sample-inefficiency [Dulac-Arnold et al., 2019]. Moreover, our implementation can handle continuous state and action spaces.
We compare the performance of our algorithms to classical portfolio optimization tech- niques such as Mean-Variance (MV) and Equal Risk Contribution (ERC), and to popular reinforcement learning techniques such as Deep Deterministic Policy Gradient (DDPG) and Soft Actor-Critic (SAC). We observe our implementation has higher sample-efficiency compared DDPG and SAC, and higher cumulative returns on the test set compared to MV, ERC, DDPG, and SAC.
This dissertation aims to develop a comprehensive and multi-scale approach for assessing the rejuvenation efficiency and mechanisms of various rejuvenator-aged bitumen blends. The combination of molecular dynamics (MD) simulations prediction and experimental validation is throughout the whole thesis to evaluate the compatibility potential and diffusive capacity of rejuvenators within aged bitumen, as well as their rejuvenation effectiveness in the chemo-thermodynamic-rheological performance. Additionally, the intermolecular interactions occurring between the rejuvenator and aged bitumen molecules are visualized and quantified by MD simulations.
The accurate construction of molecular models for aged bitumen is crucial for investigating the fundamental effects of aging on bitumen behavior at the molecular scale. To accomplish this, the long-term aging influence on the chemical characteristics of bitumen was assessed through Saturate, Aromatic, Resin, and Asphaltene (SARA) fractionation, Fourier Transform Infrared Spectroscopy (FTIR) test and element analysis method. The chemical information obtained served as a foundation for determining the molecular structures of bitumen models. Various thermodynamic parameters of both virgin and aged bitumen were predicted to fundamentally evaluate the aging effect on bitumen properties. Lastly, functional group and SARA-based long-term aging reaction kinetics models were proposed to anticipate the chemical characteristics of aged bitumen with different aging degrees, thereby establishing the corresponding molecular models without the need for additional experimental procedures.
Simultaneously, novel average and multi-component molecular models for various rejuvenators (bio-oil BO, engine-oil EO, naphthenic-oil NO, aromatic-oil AO) were established. The average models were based on the average chemical characteristics, such as functional group distribution, element component, and average molecular weight. On the other hand, multi-component models were derived from molecular component distribution in rejuvenators through Gas Chromatography-Mass spectrometry (GC-MS) analysis. Both models were validated by comparing MD outputs with experimental results. It was found that the average models provided more accurate predictions regarding the glass transition temperatures, especially for the aromatic-oil. Additionally, a range of thermodynamic parameters for the rejuvenators were predicted and compared. Finally, the average structures of rejuvenators were adopted to construct subsequent molecular models of rejuvenated binders.
The consideration of compatibility between the rejuvenator and aged bitumen is crucial due to the potential phase separation. In this thesis, different thermodynamic parameters, such as solubility parameter difference Δδ, Flory-Huggins parameter\chi, and mixing free energy ΔGm were predicted and calculated using MD simulations for various rejuvenated bitumen systems. The predicted compatibility ranking for four rejuvenators was AO > BO > NO > EO, aligned with the experimentally measured thermal stability results. Moreover, separation index (SI) parameters based on rheological and chemical indices were available to assess the thermal stability of rejuvenated bitumen.
Furthermore, a comprehensive investigation was implemented to explore the effects of rejuvenator type, temperature, and aging degree of bitumen on the diffusion behavior of rejuvenators in aged binders at multiple scales. The molecular dynamics (MD) simulation method was employed to detect the molecular-level diffusion characteristics of rejuvenators and predict their diffusion coefficient (D) parameters. At the atomic scale, it was observed that there was a mutual but partial interfacial diffusion feature between rejuvenators and aged bitumen molecules. Meanwhile, the concentration distribution of rejuvenator molecules in aged bitumen was well described by Fick's Second Law. The calculated D values for the four rejuvenators ranged from 10-11 to 10-10 m2/s, and the diffusive capacities followed the order of BO > EO > NO > AO. To verify the MD simulation outputs, diffusion tests and dynamic shear rheometer (DSR) characterizations were conducted. The experimental results regarding the magnitude and order of the D values were in good agreement with the MD simulation findings. Lastly, it was observed that an increased aging degree of bitumen had a negative impact on the molecular diffusivity of BO, EO, and NO rejuvenators, whereas the D value of AO molecules enlarged as the aging level deepened.
A series of measurements were conducted to estimate the combined effects of rejuvenator type/dosage and aging degree of bitumen on the rheological properties of rejuvenated bitumen. Importantly, several critical indicators were identified that effectively assess and differentiate the rejuvenation efficiency of different rejuvenators on aged bitumen performance. In terms of high-temperature performance, parameters rutting failure temperature (RFT) and zero-shear viscosity (ZSV) from the linear viscoelastic (LVE) and flow tests were found to be useful. Additionally, parameters R3.2, Jnr0.1 or Jnr3.2, and Jnrslope were recommended for estimating the elastic performance, creep potential, and stress sensitivity of rejuvenated bitumen. Among these, the RFT parameter played a crucial role in evaluating and distinguishing the rejuvenation effectiveness of various rejuvenators on the high-temperature performance of aged bitumen. For the low-temperature relaxation property, parameters τ50s, t25%, and A were proposed as critical indicators. Regarding fatigue life improvement, BO demonstrated the highest rejuvenation effectiveness, followed by EO, NO, and AO rejuvenators. The fatigue failure temperature (FFT) parameter was identified as an effective indicator for fatigue performance evaluation in LVE tests. In linear amplitude sweep (LAS) tests, the fatigue life (Nf5), peak strain (ɛsr), and elastic modulus (E) parameters were optimized as effective fatigue indicators. Nonetheless, crack width (C) results were consistent with conclusions drawn from LVE and LAS tests. Particularly, the crack width C500 parameter showed strong correlations with other critical fatigue indicators, and its prediction could be achieved using correlation equations without the need for time-consuming TS tests.
At the atomic-level evaluation, several key thermodynamic properties of variable rejuvenated bitumen models were outputted by molecular dynamics (MD) simulation. The rejuvenation effectiveness of different rejuvenators on the thermodynamic indices of aged bitumen was estimated and compared. Importantly, the potential connections between these essential nanoscale parameters and critical macroscale indicators in terms of high-and-low temperature performance and fatigue behaviors of rejuvenated binders were explored. It was revealed that the addition of rejuvenators inherently catalysed a restoration of density and cohesive energy density (CED) values toward those of virgin bitumen. A suite of indicators, including UVEP, UWEK, EN, UVET, UNED, and ECT, are introduced as critical energetic parameters, each reflecting rejuvenator efficacy on atomic-level energetic features, except for specific cases involving aromatic-oil rejuvenated binders. Meanwhile, it is recommended to predict the relaxation properties of different rejuvenated bitumen by the fractional free volume parameter from MD simulation. The surface free energy (γ) emerges as a dependable index for assessing the rejuvenation efficacy of the cohesive cracking potential of aged bitumen.
In summary, a multiscale evaluation framework of rejuvenated bitumen was proposed and developed in this dissertation, together with a full understanding of the difference in rejuvenation efficiency and mechanism between various rejuvenators on chemo-thermodynamic-rheological performance restoration of aged bitumen. The outcomes of this thesis would be beneficial to promoting the formation of classification standards of rejuvenator additives, development of advanced multifunctional rejuvenators, and improvement of all-round evaluation method on rejuvenated binder.
In the dynamic realm of medical technology, innovation to improve the lives of those with chronic conditions like Parkinson's Disease (PD) is paramount. This graduation report represents the culmination of a project aiming to address prevalent symptoms in individuals with PD.
Client and Objective:
The project aims to develop a concept product for Dopple B.V., a Dutch tech company specializing in head-worn audio smart wearables, seeking to expand into the medical market. The focus is on utilizing their existing product line to create a solution.
Scope:
The project focuses on creating a smart wearable audio device equipped with modern technology to alleviate symptoms of PD, particularly ""freeze of gait & festination.""
Symptoms:
Freeze of gait (FoG) refers to a sudden inability to move forward despite intending to walk, significantly impacting mobility and increasing fall risk. Festination involves a rapid, short-stepped gait, leading to balance issues and difficulties in movement control.
User Testing:
Tests conducted with PD clients showed promising results in evaluating the effectiveness of feedback mechanisms.
Product Features:
The ""Dopple Earbuds"" utilize advanced technology such as smartphone integration, neural networks, and Bluetooth data transmission. Beyond addressing FoG and festination, they offer a range of functionalities including object detection, heart rhythm monitoring, fall detection, posture correction, and more.
Design:
The Dopple Earbuds are designed with considerations for aesthetics, ergonomics, and materials, tailored to the needs of elderly users. The involvement of neural networks necessitates careful management of memory, battery consumption, and data flow.
Collaboration:
The project involved collaboration with healthcare professionals, Dopple engineers, and coaching, aiming to pioneer novel solutions in medical technology beyond traditional pharmaceutical approaches.
In summary, this project represents a significant step forward in leveraging technology to improve the quality of life for individuals with PD, showcasing the potential of medical assistance technology in complementing existing treatments.","Smart Wearables; Parkinson's Disease; freeze of gait; posture correction; fall detection; parkinson; Medesign; Medical products; Healthcare Design","en","master thesis","","","","","","","","","","","","Integrated Product Design | Medisign","","52.002100, 4.369900"
"uuid:b0b59ea3-e649-40c6-ac0a-b2dc1f598af1","http://resolver.tudelft.nl/uuid:b0b59ea3-e649-40c6-ac0a-b2dc1f598af1","Coastalock™ Performance on a Permeable Breakwater Slope: Model Tests on the Influence of a Permeable Core, Unit Modifications and Toe Support on the Hydraulic Performance of an Ecological Armour Unit","Ławniczak, Aron (TU Delft Civil Engineering & Geosciences)","Hofland, Bas (mentor); Gutiérrez Martínez, Jorge (graduation committee); van den Bos, J.P. (graduation committee); van Gent, M.R.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Coastal areas face increasing threat from erosion. The use of coastal protection structures is imperative to counter this. Concrete “armouring” is widely used due to durability and cost-effectiveness. Conventional methods of “armouring” result in habitat degradation and loss of biodiversity. ECOncrete developed Coastalock, an armour unit designed to provide coastal protection but also to create marine habitats.
Initial tests conducted on impermeable slopes in deep water conditions revealed, that tightly placed units experienced pressure gradients across the top layer, leading to failure. The aim of this study is to investigate the hydraulic performance of Coastalock, both with and without modification, within permeable breakwater structures. The study examines the influence of toe berms on different surfaces, assessing the armour layer’s susceptibility to sliding.
The research aims to bridge existing knowledge gaps regarding Coastalock behavior under varying wave conditions through literature review and physical model tests conducted in the 2D wave flume at TU Delft.
Structure from motion photogrammetry enabled the creation of 3D models of the armour layer after wave attack, facilitating the tracking of armour layer deformation of selected test series. The research includes measurements of overtopping discharge and reflection coefficient.
The findings shed light on failure mechanisms observed in Coastalock armour layers on permeable core slopes, attributed to built-up pressures exceeding self-weight and interlocking capabilities during wave run-down. 'Breathing' involves upward movement perpendicular to the slope during wave run-down and downward movement during wave run-up. Friction and partial interlocking contribute to the formation of a bulge in the armour layer, growing in size and magnitude, leading to extraction.
Observing increased 'breathing' and extraction thresholds with larger inter-unit void sizes, was confirmed for permeable cores. No stability increase compared to impermeable core was found, attributed to reduced maximum run-down levels. A lowering of overtopping and reflection was found for the permeable core.
The protrusions implementation necessitated a new configuration, termed the 'Protrusion Optimized' configuration, with an orientation change from cavity upwards to downwards at SWL. 10% protrusions reduced the stability number threshold for 'breathing', while 22.5% protrusions prevented filter layer migration and reached up 𝑁𝑠=4.2 without 'breathing' or extraction. A stability increase was found in 𝑠0𝑝=0.02 conditions, attributed to the ‘reservoir effect’. Incorporating protrusions and transitioning to the 'Protrusion Optimized' configuration increased reflection due to increased surface area and reduced permeability.
Changing the orientation location towards the midpoint between SWL and the bottom row or facing all units upwards resulted in increased stability in terms of ‘breathing’ and extraction, as well as a downslope shift of the damage location. Upwards-oriented units led to smoother slopes and higher reflection coefficients, both attributed to the water retaining properties of the cavity.
The presence of toe berms, showed no significant impact on damage progression or the location. Downslope movement well below the threshold indicative of near extraction was observed.
Recommendations for advancing 22.5% protrusions are proposed, advocating a Ns=2.6 for surging waves in deep water conditions. This design offers notable overtopping reduction, orientation flexibility, and reduced concrete usage and project duration.
A design science research methodology was used for this research where two interwoven artefacts were developed. The first artefact was a contextualized trust model based on three trustworthiness factors: integrity, ability and benevolence. The second artefact was a demonstration for the HMLS using a technological model.
The trust model was validated through expert interviews and enriched with additional information. Based on the feedback from the expert interviews, nine meta-requirements for the technological model were developed. The proposed solution for the design of the HMLS is to automatically distribute fractional ownership of mortgages via Non-Fungible Tokens (NFTs) through an ecosystem with the traditional finance company as originator and public investors as lenders. The ownership of the NFTs is transparently tracked via the blockchain to monitor the fractional ownership of a home. These NFTs exist in mixed token pools and are controlled by the traditional finance companies. These pools are supplemented with other digital assets to create different risk profiles to suit different types of investors. A demonstration of these token pools is shown, with an overview of the architecture explaining the mortgage application and transaction processes through the different layers. Finally, a stakeholder map is shown and their roles within the ecosystem are explained. The research provided new insights by making the second model dependent on the first. The findings highlight new challenges for further research, such as prototyping or improving the versatility of the model.
Through theoretical analysis and practical experimentation on device memory usage during training, we demonstrate that our approach incurs minimal additional memory overhead for inter-device communication. Evaluation on synthetic and realistic datasets, including the Inria Aerial Image and DeepGlobe Satellite Segmentation datasets, demonstrates the effectiveness of our approach. Our model achieves competitive performance compared to the baseline U-Net model, with consistent class predictions around boundaries. Visualization of feature maps highlights the role of the communication network in transferring contextual information. Furthermore, it is shown that our approach remains scalable even when trained on limited subdomains.
In conclusion, our proposed model offers an intuitive solution for segmenting ultra-high-resolution images by effectively incorporating spatial context. Future research could explore variations of our model, such as overlapping subdomains or communication on different levels of the U-Net, to further enhance boundary consistency and information transfer.","CNN; Domain Decomposition; Machine learning; high resolution; image segmentation","en","master thesis","","","","","","","","","","","","Applied Mathematics","",""
"uuid:f3ed96a3-c436-4027-a3fc-5c22a9ee905d","http://resolver.tudelft.nl/uuid:f3ed96a3-c436-4027-a3fc-5c22a9ee905d","Systems for Digital Self-Sovereignty","Stokkink, Q.A. (TU Delft Data-Intensive Systems)","Epema, D.H.J. (promotor); Pouwelse, J.A. (promotor); Delft University of Technology (degree granting institution)","2024","The digital world is evolving toward representing - and serving the interconnection of - natural persons. Instead of depending on the intrastructure of Big Tech companies and governments, users can cooperate and use their hardware to form public infrastructure. Instead of existing by virtue of a reference in some institution's database, users can interact based on a digital representation of their own choosing. It is no longer sufficient to depend on users to act out of system-imposed altruism. A new digital world is emerging that aims to provide systems that respect the rights of users to control their own digital representation. The complete control over one's own representation and all the data that belongs to it is what we know as Self-Sovereignty.
Solutions for digital Self-Sovereignty are wildly sought after, though their solution space remains woefully underexplored. Numerous global entities, e.g., the European Union, have stated their support for Self-Sovereign systems. However, many old problems of peer-to-peer systems that have gone ignored for decennia resurge with the need for Self-Sovereignty. For example, interconnections in peer-to-peer networks are vulnerable to attacks using fake identities and attackers can manipulate peers by depriving them of data. As most deployed peer-to-peer solutions have very little incentive for disruption by attackers, we have seen very few attacks. However, cryptocurrencies have shown that these attacks do surface when there is sizable monetary gain for attackers. In order to secure our future digital society, we must define and study these systems for Self-Sovereignty.
In this thesis we take the first steps toward defining the systems that can power a Self-Sovereign ""Web3"" ecosystem. In particular, we explore systems that apply Self-Sovereignty for identity, for public infrastructure, and for the execution of shared code. We describe four prototype mechanisms to form a guide for future work and to derive their general properties. Each mechanism is evaluated as realistically as possible. Thereby, this thesis mostly fulfills an exploratory role to guide the further evolution of our digital world.","anonymity; Web3; Sybil; smart contract; Self-Sovereign; reputation; replication; pseudonymity; privacy; peer-to-peer; network latency; network; local-first; identity management; green; gossip; decentralization; blockchain","en","doctoral thesis","","978-94-6366-839-2","","","","","","","","","Data-Intensive Systems","","",""
"uuid:9c68e22c-c0a8-47db-9e6f-ba7b4ae7f79a","http://resolver.tudelft.nl/uuid:9c68e22c-c0a8-47db-9e6f-ba7b4ae7f79a","Automated implant configuration optimisation for high dose rate brachytherapy","Dirks, Remco (TU Delft Mechanical Engineering; TU Delft Cognitive Robotics)","Alonso-Mora, J. (mentor); Straathof, R. (mentor); Fereidoonnezhad, B.F. (graduation committee); Breedveld, Sebastiaan (graduation committee); Delft University of Technology (degree granting institution)","2024","Brachytherapy (BT) is an essential component in the curative treatment of cervical cancer. With commercial BT implant devices, called applicators, the radioactive sources can only be positioned in fixed intracavitary channels or in a fixed array of interstitial needles. Patient-tailored BT applicators containing individualised needle channels have the potential to enhance the delivered dose to the tumour while minimising tissue damage of the organs-at-risk (OARs). During the optimisation process of the needle channels, several constraints must be considered. The needle paths in the applicator are curvature-constrained, and the needles should not collide with each other or potentially perforate OARs. Furthermore, clinicians can impose additional constraints based on their preferences.
Existing approaches in literature for optimising needle placement in patient-tailored BT applicators for cervical cancer treatment have employed various algorithms. However, these approaches often rely on significant approximations. For instance, some assume that all needles are inserted in parallel or focus solely on optimising geometric coverage as opposed to optimising the dose distribution. Moreover, the few methods in literature incorporating needle path planning in the optimisation process require manually pre-specified dwell positions. To improve dose conformity and minimise the dependence on the clinician’s expertise and time, there is a need for the development of software that optimises the needle placement and paths without resorting to these severe assumptions.
This work proposes and validates a novel three-stage approach to generate a patient-tailored applicator configuration without resorting to fully geometric optimisation. First, a high-potential set of dwell positions is obtained by running a modified version of the dwell time optimisation software BiCycle (Erasmus Medical Centre, Rotterdam, the Netherlands) on a grid of possible dwell positions. This results in a resolution optimal treatment plan when not considering geometry and applicator constraints. The positions with the highest dwell times according to the resolution optimal treatment plan are selected in the high-potential set. Next, a weighted set cover problem is used iteratively to find a combination of feasible needle segments to cover all dwell points in the high-potential set at a minimum distance. Lastly, needle channels to steer the needle to these segments are simultaneously optimised to be of minimum curvature and mutually collision-free.
To evaluate our approach, a virtual configuration and planning study was performed in a cohort of 22 locally advanced cervical cancer patients previously treated with the Venezia (Elekta AB, Stockholm, Sweden). The resulting treatment plans of the clinically used configuration were compared with the resulting treatment plans of the proposed patient-tailored and grid configurations on clinically relevant dose-volume histogram parameters, dwell times, conformity index and number of interstitial needles. Statistical significance is assessed with Wilcoxon signed-rank tests.
The proposed workflow was demonstrated to be feasible, and for every patient, a configuration could be generated in clinically acceptable time. All treatment plans generated for the grid configuration, the patient-tailored configuration and the clinical configuration were acceptable following the EMBRACE ll aims. Planning aims, however, were met more frequently with both the grid configurations (145/151 instances) and the patient-tailored configurations (137/151 instances) in comparison with the clinically used configurations (119/151 instances). The treatment plans generated with the grid configurations obtained significantly better (p < 0.01) median normalised CTVIR D98 dose with respect to the clinical configurations. Moreover, with the grid configurations, there was a significant improvement in median normalised D2cm3 dose for the bladder (p < 0.001), rectum (p < 0.001), sigmoid (p < 0.01) and bowel (p < 0.001) compared to treatment plans obtained with the clinical configurations. The treatment plans generated with the patient-tailored configurations obtained comparable target doses, but median normalised D2cm3 doses for the bladder (p < 0.001), rectum (p < 0.01) and bowel (p < 0.01) were significantly better for the patient-tailored configurations compared to the clinical configurations.
The proposed automated patient-tailored BT source channel configuration planning method was demonstrated to be clinically feasible. The resulting treatment plans have dosimetric advantages over the treatment plans generated with the clinical applicator configuration. Improvements to the intracavitary dwell position placement are expected to further increase dose conformity.
This thesis conducts a Social Cost-Benefit Analysis to assess the viability of subsidizing hydrogen fuel cell heavy-duty trucks in the Netherlands. By examining both costs and benefits, it aims to offer insights into the societal implications of transitioning from diesel to hydrogen trucks. Using a mixed-methods approach including stakeholder interviews and data analysis, the study evaluates emission reductions and social gains associated with this subsidy program.
The analysis considers two scenarios based on the future market share of hydrogen trucks and three subsidy program initiation dates (2024, 2030, and 2040), extending the assessment until 2050. Results indicate that initiating the subsidy program in 2024 yields the most favourable outcomes, yielding positive Net Present Values of 1.8 billion euros and 2.4 billion euros for the respective scenarios. Nevertheless, substantial subsidy costs are anticipated, with estimated expenses of 4 billion euros and 12 billion euros for each of the two 2024 scenarios, surpassing the government's proposed budget.
The study highlights uncertainties related to infrastructure costs and assumptions regarding economies of scale, underscoring the need for further investigation before implementing the subsidy program. Addressing these uncertainties is crucial for achieving a more precise understanding and ensuring the social viability of transitioning to hydrogen fuel cell heavy-duty trucks in the Netherlands.
foundations used in the Netherlands is pile foundations which are typically founded on a thick sand layer in the subsurface. These pile foundations are the focus of this thesis and more specifically the methods used to design such foundations. This thesis aims to give a better understanding of the resistance of closed-ended piles in a layered soil by comparing existing pile design methods to the measured forces from the Drukpaal jacking machine. Drukpaal jacks precast concrete piles into the soil and the records collected give a valuable insight in the pile resistance in various locations and soil profiles with layered soil in the Netherlands.
The design of a pile foundations consists of the combination of two different types of methods. One will predict the base capacity of the pile foundations and the other will predict the shaft capacity. These two capacities together give the predicted bearing capacity of the pile. However, multiple base capacity and shaft capacity methods exist with varying influence zones and with that varying degrees of accuracy. In this thesis the different base and shaft capacity methods used are all based on the tip resistance as measured by a CPT. The following base capacity methods are included: Koppejan, LCPC, Filter method and the Filter method as adapted by Munta de Boorder (in this thesis referred to as the Munta de Boorder method). And for shaft capacity the NEN method and the ISO method are used.
This thesis aims to answer the following research question: What combination of capacity prediction methods for shaft and tip resistance works best to estimate the total force over depth as measured by Drukpaal?.
This question will be answered by a series of simulations of different projects completed by Drukpaal, which is a company which jacks piles into the ground and records the required force over depth.
The measurements and simulations for the various sites were compared both visually and
statistically. The Filter method with ISO gives the best visual fit.
For the statistical analysis the coefficient of variance (COV) is taken as well as the root mean squared error (RMSE) of the ratio line of the simulation (simulation divided by the measurement). Here the COV will account for the shape and the RMSE will account for the overall error. The sum of these two values is used to determine the best fit, since both of these values should be as small as possible. From this analysis it is found that Filter method in combination with ISO is overall the best combination, followed by Munta de Boorder with ISO and Filter method together with NEN.
The last aspect to be looked at is the location dependency of the combination of methods. From this it was found that the base capacity methods in combination with NEN vary a lot over the measured locations and these combinations are thus location dependent. For the base capacity, the LCPC method was also found to be location dependent in combination with ISO. So even though this combination worked really well for one of the projects (Gorinchem) it is not dependable to use because of the varying degrees of accuracy. The other three combinations; Koppejan, Filter method and Munta de Boorder together with ISO, were all found to be location independent. However, Koppejan with ISO garnered quite high values for RMSE and COV, meaning that this combination is not very accurate.
Overall, Filter method with ISO was found to give the best fit which was location independent. Munta de Boorder with ISO followed and Koppejan with ISO was found third best fit. The other combinations were found to be location dependent and thus are, based on the work in this thesis, less suitable for application in The Netherlands.","Pile driving; Pile capacity; CPT; averaging distance; Pile foundations; pile base capacity; Pile shaft capacity","en","master thesis","","","","","","","","","","","","Geo-Engineering","",""
"uuid:27dd7f9c-92f0-4e3f-b3c9-0109b197eb38","http://resolver.tudelft.nl/uuid:27dd7f9c-92f0-4e3f-b3c9-0109b197eb38","Synthetic data generation for research – enabler for privacy-enhancing health data sharing?: A multidisciplinary research on synthetic data generation in healthcare","van der Wel, Iris (TU Delft Technology, Policy and Management)","de Reuver, Mark (mentor); Hinrichs-Krapels, S. (graduation committee); Oosterhoff, J.H.F. (graduation committee); Delft University of Technology (degree granting institution)","2024","Data-driven health research, specifically the development of AI models, is hampered by poor data availability and associated administrative burdens, caused complex and fragmented data protection regulation. To reap the benefits of using high quality health data, while safeguarding data protection of patients, the synthetic data generation is seen as a promising privacy-enhancing technology to avoid the need for personal data sharing. Although synthetic data is widely discussed, research primarily focuses on a technical development and evaluation of data protection, leaving substantive matters on the use of synthetic data within its institutional context open. By combining legal and technical knowledge, this thesis aimed to bridge this gap, by analysing how synthetic data generation could enable health data sharing for research in a privacy-enhancing manner. Specifically, a design science research approach is followed to combine the requirements from the institutional environment, focusing on a use case with a Dutch healthcare provider and research institute, with scientific knowledge on synthetic data generation and data protection evaluations. The research objective was to design a framework that structures the data protection-related factors that influence the extent to which synthetic health data enables secondary use of health data for research. The identified barriers and drivers of synthetic data generation focus on the health data sharing process, the interplay between the legal definition of anonymisation and technical data protection evaluations, as well as data protection principles. Synthetic data can enable secondary use of health data for research, but, measures should be implemented in the various phases of synthetic data sharing to safeguard patients’ data protection. As policy opportunity, this thesis argues for narrower definition of personal data to support privacy-enhancing technologies such as synthetic data generation.","Synthetic Data Generation; Personal data protection; Healthcare; Secondary use of health data; Privacy-Enhancing Technology; IAD framework","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:b0470c3d-f922-4019-89cc-fdac1bb380ee","http://resolver.tudelft.nl/uuid:b0470c3d-f922-4019-89cc-fdac1bb380ee","Development of a Finite Element Model of the Achilles Tendon: Evaluating Local Displacement Estimation","Beinema, Rimke (TU Delft Mechanical Engineering; TU Delft Biomechanical Engineering)","van der Kruk, E. (mentor); Tümer, N. (mentor); de Vos, Robert-Jan (mentor); Gijsen, F.J.H. (graduation committee); Delft University of Technology (degree granting institution)","2024","Achilles tendinopathy (AT) is a common Achilles tendon injury, yet its exact cause and the factors influencing progression of individuals remain unclear. Strain distribution is indicated to play a significant role in the progression, possibly linked to the twist of the subtendons. Pizzolato et al. (2020) proposed an integrated framework for studying Achilles tendon mechanics, including a finite element (FE) model estimating local displacements in the Achilles tendon. However, before im- plementing this in AT research, further testing and validation is necessary. Therefore, to make a start for future improvements, this study aims to build a foundational FE model of the Achilles tendon, verify it with in vivo local displacement data and assess the sensitivity to subtendon twist. 3D ultrasound and X-rays of the ankle provided the geometry and the moment arm of the Achilles tendon, respectively. By minimizing the error between the tendon’s elongation during contraction and the FE model prediction, the material properties were optimized. Local displacements in the sagittal and coronal plane were computed using estimated forces from in vivo studies. Simulated subtendon twists (11◦, 37◦, 65◦) examined the effect of the amount of twist on the displacement. Comparing the FE estimated local displacements to in vivo data indicated that additional substructure details are needed to accurately calculate the displacement behavior. Modifying fiber twist angles altered the uniformity of the displacements in the FE model. Therefore, further development of the FE model of the Achilles tendon is recommended before incorporating it into an Achilles tendon mechanics study.","Finite Element Analysis; Achilles Tendon; Displacement","en","master thesis","","","","","","","","","","","","Mechanical Engineering | BioMechanical Design","",""
"uuid:ca8b3b1e-41db-4481-a5ab-f4f6d446ed2d","http://resolver.tudelft.nl/uuid:ca8b3b1e-41db-4481-a5ab-f4f6d446ed2d","Sustainability of bio-based plastics in a circular economy","Ritzen, L. (TU Delft Design for Sustainability)","Balkenende, R. (promotor); Bakker, C.A. (promotor); Sprecher, B. (copromotor); Delft University of Technology (degree granting institution)","2024","Plastics have become indispensable in modern life due to their versatility and affordability. However, their widespread use has resulted in far-reaching environmental damage, including the accumulation of plastic waste, fossil fuel depletion, and significant greenhouse gas emissions. Bio-based plastics have been proposed as a sustainable, circular solution to the environmental issues associated with plastics. However, bio-based plastics are not implicitly sustainable or circular. These aspects are influenced by how a plastic is produced and how it is recovered at end-of-life, implying that careful attention needs to be paid to material development and product design. This thesis explores the sustainability and circularity of bio-based plastics by looking at: how they are perceived by value chain actors, potential recovery pathways in a circular economy, and environmental impact.
Although bio-based plastics have the potential to be sustainable, the emissions associated with producing them depend heavily on the biomass sourcing. At the same time, bio-based plastics are not de-facto biodegradable and thus efficient recovery at end-of-life needs to be guaranteed. Circular product design with bio-based plastics requires careful consideration of biomass sourcing and recovery. Although much information regarding these aspects is still missing, the research presented in this dissertation provides some guidelines for circular product design with bio-based plastics. In order to reduce environmental impacts, bio-based plastics should be produced with agricultural by-products or with biomass types with a high conversion efficiency. Biomass for bio-based plastics should be cultivated with minimal use of land, water, chemicals and fossil fuels. Environmental impacts can be reduced further by using renewable energy in the production process. Product designers should also consider what recovery pathway they want to target at end-of-life of a product. The plastic composition and product architecture need to reflect the targeted recovery pathway.","","en","doctoral thesis","","978-94-6384-555-7","","","","","","2024-04-08","","","Design for Sustainability","","",""
"uuid:4e23fb2f-6539-44b7-bab2-6c6b2fd7ce8d","http://resolver.tudelft.nl/uuid:4e23fb2f-6539-44b7-bab2-6c6b2fd7ce8d","Towards Robust Automatic Question Generation For Learning","Zhu, P. (TU Delft Web Information Systems)","Houben, G.J.P.M. (promotor); Hauff, C. (promotor); Delft University of Technology (degree granting institution)","2024","Questions are critical for information-seeking and learning. Automatic Question Generation (AQG) involves the subjects of Information Retrieval (IR) and Natural Language Processing (NLP), and focuses on automatically creating questions for various applications, subjects which have been studied for decades. In this thesis, we study how to create a robust automatic question generation system from several aspects, including data creation, evaluation, and effects of question generation.
First, we contribute to the quality evaluation of the generated questions. Specifically, we introduce three new evaluation metrics and compare the effects of applying the automatic evaluation metrics as rewards for reinforcement learning-based question generation system training. Question quality evaluation is an essential part of AQG systems. It is further used in this thesis in dataset creation, question selection for self-training, and filtering automatically generated questions shown for learners.
Data are essential for building AQG systems. In Chapters 3 and 4, we focus on data quality control in two main methods of dataset creation: collecting user-generated resources from online platforms and from crowdsourcing. Specifically, we start by investigating the information overload issue in MOOC forum discussions caused by unuseful, unlabeled, and unstructured data. We propose a framework for clip recommendation that includes useful question classification and a neural ranker. We further investigate training the neural ranker with both labeled and weakly labeled data. We then study how to infer the true answer span from multiple crowdsourced annotations automatically. We propose an approach to effectively utilize the quality of each answer annotation and its relation to other answer annotations for answer aggregation. Despite the various available methods of collecting labeled data, there are many application domains where the labeled data is hard or expensive to harvest. In Chapter 5, we move to automatically adapting the AQG model trained on label-data-abundant domains to strange domains with few labeled data.
With the impressive advantages of automatic question generation methods, it is critical to understand how the generated questions on humans. Finally, in Chapter 6, we turn to study the effects of automatically generated questions on the learners’ behaviours and learning outcomes when they serve as the adjunct questions in the informal search as learning scenario. We conduct an extensive user study to shed light on this topic.","question generation; domain adaptation; adjunct questions","en","doctoral thesis","","","","","","","","","","","Web Information Systems","","",""
"uuid:6bca69cf-d75b-4bd1-a39f-d0352ee1a8c9","http://resolver.tudelft.nl/uuid:6bca69cf-d75b-4bd1-a39f-d0352ee1a8c9","Policy Innovation in the Heat Transition: Assessing Policy Innovation in the Sustainable Heating Transition in the Dutch Built Environment","Spoelstra, Siemen (TU Delft Technology, Policy and Management)","Hoppe, T. (mentor); Correljé, A. (graduation committee); Goyal, N. (graduation committee); Huber, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","This master's thesis explores the role of policy innovation of policies, programs, and policy instruments within the domain of heat transition in the built environment in the Netherlands, focusing specifically on the role of municipalities in navigating this complex transition towards a natural gas-free future by 2050, as mandated by the National Climate Agreement (2019).
Introduction
The research starts by outlining the ambitious goal of the Dutch government to significantly reduce CO2 emissions by 2050, emphasizing the critical target of reducing natural gas usage in the built environment in the Netherlands. The introduction highlights the urgent need for innovative policy approaches to accelerate the heat transition, especially in light of geopolitical factors such as the crisis in Ukraine, which underscore the urgency of energy independence.
Theory
Starting with a literature review regarding the different conceptual defnitions of (policy) innovation and the framework provided by Schaffrin et al. (2015), the study delves into the concept of policy innovation, exploring its significance in the context of the heat transition in the built environment. The research identifies the multifaceted nature of innovation, encompassing the novelty of policies, their adoption, and eventual impact. The theoretical foundation emphasizes the importance of analyzing policy output to gauge the extent of innovation within municipalities' strategies for the heat transition.
Methodology
An exploratory study design using qualitative research methods is outlined, focusing on a case study analysis of Transition Vision Heat (TVH) documents from ten of the most populous municipalities in the Netherlands. The research adapts and modifies Schaffrin et al.'s (2015) framework to assess policy output and innovation to fit the context of the heat transition in the built environment in the Netherlands, employing Atlas.ti software for document analysis. The methodology section discusses the selection criteria, data collection, and analysis processes, highlighting the study's systematic approach to evaluating policy documents.
Results
The results section presents a detailed analysis of policy output across eight categories, revealing a spectrum of innovation levels among the analyzed municipalities. Amsterdam is noted for its high scores in integration, target groups, and alternative technologies, showcasing a proactive approach to the heat transition. Furthermore, TVHs were scored using the modified framework of Schaffrin et al (2015). This research identifies significant differences in policy integration, stakeholder involvement, and the specificity of alternative solutions across municipalities. Despite these differences, commonalities include a shared commitment to updating the TVH every five years and aiming for a gas-free environment by 2050.
Conclusion
The thesis concludes that while Dutch municipalities exhibit a range of innovative strategies in their approach to the heat transition, there is room for improvement, particularly in setting concrete targets and detailed implementation procedures. The study advocates for municipalities to take a more directive role in leading the heat transition, emphasizing the need for tailored and innovative solutions that reflect local contexts. The research suggests that a comprehensive, collaborative, and context-specific approach is essential for successfully navigating the complexities of the heat transition toward a sustainable, natural gas-free built environment in the Netherlands.
Discussion
The discussion emphasizes the scientific added value of adapting Schaffrin et al.'s (2015) framework to the context of the heat transition in the built environment, underlining the importance of scope on alternate technology solutions and the target groups involved. Limitations such as the subjective nature of measuring policy innovation and the representativeness of the sample size are acknowledged. The section also suggests the need for future research to include broader samples and expert validation to enhance the framework's reliability. Furthermore, the role of local initiatives and the inclusion of residents' opinions and viewpoints in TVHs are emphasized as crucial for developing tailored, context-specific policy solutions. The involvement of residents (e.g., in the form of communities) can contribute to a more appropriate approach that contributes to the advancement of the heat transition in the built environment in the Netherlands.
parameters include the number of LH2 fuel trucks, LH2 flow rate, LH2 aircraft penetration rate, LH2 refueling safety zone diameter and the level of restricted parallel turnaround processes during LH2 refueling. Through varying these parameters in experiments using an agent-based simulation model, meaningful results could be obtained which are useful to consult airports and airlines on what operational and infrastructural measures need to be accommodated to ensure competitive ground operations in terms of efficiency involving LH2-powered aircraft. The impact of the different experiments on the efficiency was expressed in terms of the turnaround time, number of aircraft delays and on-time performance of both Jet-A1 and LH2-powered aircraft. As a case-study, the ZEROe turbofan was selected to operate at the regional airport Rotterdam The Hague Airport, featuring remote aircraft stands. The results show that the LH2 penetration rate has the greatest influence on the efficiency of the ground operations,
and increasing this rate must be carefully coordinated by the involved stakeholders in accordance with technological developments of the remaining four parameters. For a LH2 penetration rate of up to 25%, at least 50% of the turnaround processes must be allowed to be executed during refueling, the safety zone diameter must not be greater than 30 meter and a single LH2 fuel truck with a flow rate of at least 5 kg/s is required to ensure efficient ground operations. To accommodate LH2 penetration rates up to 50%, there must be no restrictions on parallel turnaround processes, the safety zone diameter should be 15 meter and finally at least two LH2 fuel trucks are required with a flow rate of at least 10 kg/s each.","Hydrogen; LH2; Ground Operations; Turnaround procedure; Refueling flow rate; Safety zone; ABM; Airbus ZEROe; Rotterdam The Hague Airport; Penetration rate; Fuel trucks","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:da1c1f21-45d3-486a-8408-08f1531e8f13","http://resolver.tudelft.nl/uuid:da1c1f21-45d3-486a-8408-08f1531e8f13","Design of a normally closed MEMS- microvalve for micropropulsion systems in PocketQube satellites","Agarwal, Shrutika (TU Delft Aerospace Engineering)","Cervone, A. (mentor); Menicucci, A. (graduation committee); Cowan, K.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","There is a growing demand for nano-satellite missions that require advancements in micro-propulsion capabilities to facilitate a wider range of orbital maneuvers. Among these capabilities, the ability to accurately control thrust would unlock new possibilities for nano-satellite applications, including missions such as space debris removal and orbit transfer.
Delft University of Technology is currently pioneering the development of an innovative green propellant-driven micro-propulsion system based on micro-electro-mechanical (MEMS) technologies for its PocketQube, known as Delfi-PQ, which features a compact form factor of 5x5x5 cm. While the thruster itself is in development, the interfacing and integration with other components are still ongoing.
Given the stringent mass, volume, and power limitations imposed by PocketQube satellite requirements, there is a pressing need for micro-scale components to realize a highly integrated propulsion system.
This thesis focuses on the design of a MEMS-based microvalve for proportional flow control in micro-resistojets. The design is conceptualized as comprising three components working in harmony: a valve seat with inlet and outlet, a flexible membrane, and a piezoelectric actuator. The valve seat with inlet and outlet, as well as the flexible membrane, utilize MEMS manufacturing techniques and are based on a silicon chip. And, a new design for piezoelectric actuators employing the d31 mode for contraction strokes is proposed.
The proposed preliminary design is a normally closed microvalve designed for a flow rate of 5g/hr, with the flexibility to accommodate higher flow rates if needed. It offers proportional flow control, ensuring precise regulation of fluid flow. Additionally, it promises a low power consumption of less than 1W and a low response time. Furthermore, this thesis provides a detailed outline of the MEMS fabrication process flow available at TU Delft’s Else Kooi Laboratory for the device. It also features a comprehensive test plan aimed
at assessing the feasibility of this design in future studies. Additionally, the thesis includes an elaborate risk analysis to help identify and mitigate potential risks during the manufacturing and testing phases.
The design shows promise and could pave the way for future developments of the microvalve within the department.","microvalve; micro-propulsion; MEMS; PocketQube; thruster","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:0f05d52f-3b1a-4bf5-b234-8f943b4192f6","http://resolver.tudelft.nl/uuid:0f05d52f-3b1a-4bf5-b234-8f943b4192f6","Multiplicative contrast source inversion method in electrical properties tomography based on Jacobi matrix inversion","Helfferich, Florens (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Signal Processing Systems)","Remis, R.F. (mentor); Kooij, B.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","The tissue electrical properties of conductivity and permittivity affect the interactions of electromagnetic fields in the body. These properties vary throughout the different tissues as the tissue structure and composition varies. In this thesis, medical imaging and diagnosis is used as primary example to motivate exploration of a novel regularization approach to an MRI-based electrical properties tomography (EPT) method.
Total variation (TV) regularization has been shown to perform noise reduction in the iterative Contrast Source Inversion EPT (CSI-EPT) method. The Jacobi matrix inversion regularization, an alternative to the known conjugate gradient formulation, is elaborated and applied to an E-polarized MRI fields scenario such that this thesis presents the Jacobi step regularized CSI-EPT.
The alternative regularization method outperforms the known regularization method in the reconstruction qualities of noise-suppression and edge-preservation in the simulated MRI experiments using a virtual body model. Further advancements are also described, such as multiple inner-iterations Jacobi regularization and an anatomical prior initialization of the contrast function. Important future research topics are the incorporation and evaluation of the Jacobi step regularization into more advanced CSI-EPT versions, which are the three-dimensional and transceive phase based algorithms to correct realistic MRI data.","Imaging; MRI; Electrical Property Tomography; Regularization; contrast source inversion","en","master thesis","","","","","","","","","","","","Electrical Engineering | Signals and Systems","",""
"uuid:8bccc23b-4554-4ce0-8c5e-856257f306ae","http://resolver.tudelft.nl/uuid:8bccc23b-4554-4ce0-8c5e-856257f306ae","Two-layer gravity inversion on Mars: Three different inversion methods to obtain a global density model of the crust and upper mantle of Mars","van den Bogaard, Fenna (TU Delft Aerospace Engineering)","Root, B.C. (mentor); van der Wal, W. (graduation committee); De Teixeira Da Encarnação, J. (graduation committee); Delft University of Technology (degree granting institution)","2024","The origin of the Martian dichotomy is subject to question and no substantial evidence exists. Some surface and interior features that are not visible in, e.g., topography data, can show up in gravity data. Therefore, this research inverts gravity data to find a crustal and mantle global density model. Previous research performed a one-layer inversion, assuming equal mass in all columns. Also, missions like InSight do not provide global interior information, but only at the landing site. The aim of this research is to provide a global density model of both the Martian crust and upper mantle. The inversion is performed using a weighted, regularized least-squares algorithm. The gravity input consists of the residual between the MRO120F data set and the state-of-the-art gravity field model of the TU Delft. The design matrix is built using Green’s functions, which define the influence of a mass element in all different directions on a measurement point. Using this least-squares algorithm, three different methods for inversion are used. The separate two-layer inversion, the combined independent two-layer inversion and the combined dependent two-layer inversion. All three inversion methods are performed on synthetic planets as well, for verification purposes. By performing all inversions on the synthetic planets, it was found that the combined independent two-layer inversion results in a strong decoupling of short and long wavelength signals, but is not able to attribute gravity signals to different features in the crust and mantle. The combined dependent two-layer inversion does lead to a result that shows decoupling of crust and mantle features. The hypothesis is that adding different gravity components to the combined dependent two-layer inversion will further increase its accuracy. The results of the inversion methods applied to Mars are in agreement with existing research in terms of standard deviations of the crust and mantle density anomalies. The maps were also analysed geologically, where the most important conclusion is the evidence of potential impact basins in the north polar region. These can be evidence to accept the several impact theory for the origination of the Martian dichotomy. Increasing the resolution and refining the third inversion method with multiple gravity components will increase the potential of gravity inversion to define geological features of Mars.","Mars; Gravity field data; Two-layer model; Inversion; Density variations","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:1c25e888-9d60-4833-9aae-1e843061b92a","http://resolver.tudelft.nl/uuid:1c25e888-9d60-4833-9aae-1e843061b92a","Deep Learning-based Segmentation of Cracks within a Photogrammetry Solution: Fully-Supervised Learning, Transfer Learning and Photogrammetric Image Processing","Kappé, Jeroen (TU Delft Civil Engineering & Geosciences)","Lindenbergh, R.C. (mentor); Schleiss, M.A. (graduation committee); Korswagen, Paul A. (graduation committee); Kodde, Martin (graduation committee); Delft University of Technology (degree granting institution)","2024","The city of Amsterdam faces the challenge of monitoring and assessing 200 kilometers of historic quay walls, of which much is deemed to be in poor condition. A key monitoring technique used is photogrammetry resulting in deformation testing. The fundamental data source forming the basis of this deformation analysis is a collection of overlapping images acquired of the masonry quay walls. Solely focusing on deformations overlooks a potential wealth of information which could be retrieved from this imagery, like the existence of cracks in the quay walls, a key sign of potential deformation of the structure.
As manual visual inspection of this imagery is very time-consuming, this work proposes a methodology based on fully-supervised deep learning-based segmentation techniques with the goal of detecting and localizing cracks in the masonry quay walls. For this purpose, two neural networks are trained, one for the segmentation of quay walls in images, and one for the segmentation of cracks.
The neural network architectures which are considered in this work are DeepLabV3+, FPN, MANet and LinkNet, together with different encoders and loss functions. For quay wall segmentation, we adopt transfer learning on a network trained on masonry walls and fine-tune it for quay walls specifically. Here, DeepLabV3+ with ResNeXt-50 was found to be most effective, achieving a F1-score of 96.3 % on the test set. For crack segmentation, FPN with ResNeSt-50 performed best, resulting in a test set F1-score of 78.8 %.
The inference of the crack network is done with a multi-level scheme to detect cracks at different image scales and increase output confidence.
The inherent photogrammetric properties of the imagery have proven to be vital for further post-processing steps, like aggregating overlapping predictions, resulting in more prediction confidence.
Photogrammetry also enables converting pixel-wise predictions to crack length and crack width in the units of meters and millimeters respectively. The methodology additionally proposes photogrammetric image processing methods to transform neural network predictions to a 3D representation and a true-to-scale orthographic 2D image.
Additionally a concise visual evaluation has been conducted to assess the prediction performance on an otherwise unlabelled dataset.
This thesis presents an engineering effort for fully-supervised crack localization within the context of photogrammetric processed images, with generalization in mind for automatic assessment.","Image segmentation; Photogrammetry; Deep Learning","en","master thesis","","","","","","","","","","","","Geoscience and Remote Sensing","",""
"uuid:d00b577f-eace-4782-ae9f-12aa7e748004","http://resolver.tudelft.nl/uuid:d00b577f-eace-4782-ae9f-12aa7e748004","Dynamic Adaptive Policy Pathways for flood risk management in Galveston Bay: Making informed flood defence decisions for an uncertain future","van Herwijnen, Maurits (TU Delft Civil Engineering & Geosciences)","van Berchum, E.C. (mentor); Jonkman, Sebastiaan N. (mentor); Pregnolato, M. (mentor); Timmermans, Jos (mentor); Delft University of Technology (degree granting institution)","2024","Making decisions when future conditions are uncertain is a challenging endeavor. This thesis develops a framework to analyse flood risk and create Dynamic Adaptive Policy Pathways, which can provide insights in the behaviour of flood risk protection measures in many future scenarios. The pathways are used to identify robust measures, dead ends and compare measures. The framework is applied to a case study in the Galveston Bay area.","DAPP; Dynamic Adaptive Policy Pathways; Flood Risk Management; Galveston Bay; FLORES; EMA Workbench; Robust decision making","en","master thesis","","","","","","","","","","","","Civil Engineering | Hydraulic Engineering | Hydraulic Structures and Flood Risk","",""
"uuid:22d798db-61a0-47c8-a686-3602e6ee62cb","http://resolver.tudelft.nl/uuid:22d798db-61a0-47c8-a686-3602e6ee62cb","Brackish Waters: Integrating Justice in Climate Adaptation and Long-Term Water Management","Brackel, A.K.C. (TU Delft Ethics & Philosophy of Technology)","Doorn, N. (promotor); Pesch, U. (copromotor); Delft University of Technology (degree granting institution)","2024","Brackish waters can be found in transition zones between freshwater rivers and saltier seas. These dynamic coastal landscapes harbor multiple functions such as housing, agriculture, nature, and industry. Because of climate change, existing borders between fresh and saline water - and between land and water - are becoming contested. Extreme rainfall, typhoons, heat waves, and droughts occur more frequently and are expected to intensify. Shifting water levels and chloride concentrations affect which livelihoods and land use practices can be sustained in the future.
Land use transformations may be needed to adapt to climate hazards such as flooding, drought, and sea-level rise. Climate risks can be reduced when people or infrastructures are moved out of areas exposed to climate hazards. Examples of these so-called exposure reduction measures are zoning, managed retreat, buy-outs, the elevation of the water table in agricultural land or projects such as the Dutch Room for the River program. However, land use changes are often contested by the people currently living and working on those lands.
This dissertation aims to contribute to the debate about just transitions in climate adaptation and land use transitions in the Netherlands and beyond. Anticipating climate risk also means anticipating conflicts about what to protect and what to let go. Not everyone will agree about the necessity of these adaptation measures, nor about what ‘just’ climate adaptation actually means at the local level. This research therefore describes the prevalence of competing justice claims in multiple adaptation controversies. At the same time, this dissertation further develops a capabilities-based approach to climate adaptation ethics.","climate adaptation; justice; water management; conflict; involuntary land use change","en","doctoral thesis","","978-94-6384-547-2","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:293e2d2e-ce7c-4226-83d1-42a572a7fdf4","http://resolver.tudelft.nl/uuid:293e2d2e-ce7c-4226-83d1-42a572a7fdf4","Empowering Meru Farmers: Design and development of a context-adapted manual groundnut thresher for smallholder farmers in the Meru Region, Kenya","Lanning, Marte (TU Delft Industrial Design Engineering; TU Delft Design for Sustainability)","Diehl, J.C. (mentor); Schermer, W. (graduation committee); Van der Schaaf, Johan (graduation committee); Delft University of Technology (degree granting institution)","2024","In a collaborative effort spanning between the Netherlands and Kenya, this project aimed to enhance the livelihoods of smallholder farmers in the Meru region by designing a manual groundnut thresher. Recognising the importance of cultural context, I embarked on a journey guided by a cultural anthropological research approach, placing a strong emphasis on co-creation and iterative prototyping to ensure the tool’s effectiveness and usability.
Through research, several challenges faced by smallholder farmers in Meru were uncovered. Handpicking groundnuts is labour-intensive and time-consuming, limiting productivity and income generation. Additionally, there is a lack of tools available to aid in the harvest of groundnuts, and the options found in other regions, such as Asia, were prohibitively expensive or unsafe.
This project fostered a collaborative environment where stakeholders from diverse backgrounds actively participated in the design process. Farmers, engineers, and students from a local technical institute worked together to co-create solutions tailored to the specific needs and preferences of the community. This inclusive approach ensured that the final product addressed the real challenges faced by farmers on the ground.
Prototyping played a prominent role in refining the design concepts and iterating towards the final prototype. We experimented with various mechanisms and configurations to optimise the thresher’s performance and usability. Continuous feedback loops enabled us to make iterative improvements, ensuring that the final product met the standards of quality and functionality.
After multiple iterations and rigorous testing, we developed a working final prototype: the Manual Groundnut Harvester. This innovative tool streamlines the harvesting process, reducing the time and labour required to thresh groundnuts. Its design allows for easy operation by farmers of all skill levels, empowering them to increase their productivity and income. Additionally, the thresher’s cultural sensitivity ensures seamless integration into the local farming practices, further enhancing its adoption and impact.
Looking ahead, the project holds promising prospects for the future. The Manual Groundnut Harvester and its redesign have the potential to significantly improve groundnut farming in Meru, offering a sustainable solution to enhance productivity and livelihoods. Moreover, the collaborative approach serves as a model for future design projects, emphasising the importance of co-creation and cultural sensitivity in addressing complex socio-economic challenges.
In conclusion, this journey to design and develop the Manual Groundnut Harvester exemplifies the power of inclusive design and collaborative innovation. By leveraging local knowledge, expertise, and resources, we have created a solution that not only improves agricultural practices but also fosters economic empowerment and community resilience in the Meru region.","Co-creation; Emerging markets; Cultural sensitive design; Cultural anthropological research; Prototype Development","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:65ad12eb-f584-4fe3-a656-53658911545a","http://resolver.tudelft.nl/uuid:65ad12eb-f584-4fe3-a656-53658911545a","Local Path Planning for a Deep-sea Nodule Collector","Meijssen, Ries (TU Delft Mechanical Engineering)","Kooij, J.F.P. (mentor); Coraddu, A. (mentor); Xepapa, Katerina (mentor); Shyrokau, B. (graduation committee); Delft University of Technology (degree granting institution)","2024","The shift to sustainable energy sources has increased demand for Energy Transition Metals such as nickel, copper, cobalt, and manganese. To satisfy this need while reducing the negative social and environmental effects of conventional mining, Deep-sea Nodule Collection (DSNC) appears to be a feasible option. Despite its potential, DSNC encounters difficulties with path planning since it depends on imperfect global paths, which result in inefficiencies and safety issues. This thesis looks into the possibility of using a local path planning algorithm, specifically an Interpolating Curve Planner (ICP).
To assess the ICP's performance under various model hyperparameters and environmental scenarios, a simulation tool is created. The study examines how well the ICP performs in terms of area coverage, collection rate, and reliability along different hyperparameters and presurvey measurement resolutions. It integrates novel production rate objectives, previous track following, and real-time sensor measurements within an environment generated from bathymetric data.
The examined local path planner shows a step towards optimised DSNC. Further research is needed to refine objectives and the structure of the local path planning algorithm to maximize its potential in addressing DSNC challenges effectively.
However, the introduction of this framework raises several implications, particularly concerning distributive justice. To systematically identify and deliberate these implications, a Design Science Research methodology was used. This methodology involved a comprehensive literature review across various research areas including Energy Justice, Waiting List Management, and Distributive Justice. Subsequently, a qualitative and quantitative analysis was conducted to understand the impacts on waiting times for both priority and non-priority clients.
Stakeholder opinions were analyzed across different industries, revealing concerns and suggestions regarding the social prioritization framework. The quantitative analysis estimated the real impact on waiting lists, considering technical constraints and proposing distributive justice metrics such as time equity disparity and change in the estimated time-to-solution ratio.
The analysis of real waiting lists demonstrated mixed outcomes, with priority clients experiencing decreases in waiting times while non-priority clients faced delays. Some non-priority clients were needlessly delayed. Distributive justice metrics highlighted disproportionate burdens on non-priority clients. Moreover, the framework's impacts extended beyond delays to financial, and psychological effects.
Recommendations for future research include incorporating historical data, obtaining more client information, improving stakeholder feedback loops, and further analyzing other aspects of Energy Justice. Additionally, connecting quantitative implications to societal values could enhance understanding of the framework's benefits to society.
Overall, this research provides valuable insights into the implications of implementing a social prioritization framework for electricity grid waiting lists, highlighting the importance of considering distributive justice and societal impacts in policy development and decision-making processes.","Energy grid; Social Prioritization; Energy Justice; Distributive Justice; Waiting List; Energy Grid Congestion","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:8a67404c-81b8-46bf-8eac-ba440783f00b","http://resolver.tudelft.nl/uuid:8a67404c-81b8-46bf-8eac-ba440783f00b","Assembly and Connection System for Structural Reuse of Wind Turbine Blades","Kik, Robbert (TU Delft Industrial Design Engineering; TU Delft Sustainable Design Engineering)","Song, Y. (mentor); Joustra, J.J. (mentor); Delft University of Technology (degree granting institution)","2024","This project addresses the growing environmental concern surrounding wind turbine blade waste by proposing an innovative solution for structural reuse. The primary focus is developing an adaptable assembly and connection system that effectively integrates retrieved segments into new structures. The approach involves segmentation and circular design principles, aiming to preserve the value and functionality of decommissioned wind turbine blades. This report provides a comprehensive overview of the problem context, research findings, and the ongoing development and design of the assembly and connection system. The report concludes with a design proposition for a scalable geodesic dome","Structural reuse; Sustainbility by design; Wind Turbine Blade","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:1f998180-218c-41de-988f-1baf55df40ab","http://resolver.tudelft.nl/uuid:1f998180-218c-41de-988f-1baf55df40ab","Success factors and barriers in car reduction: Lessons from European cities","van der Lee, Sean (TU Delft Technology, Policy and Management)","Veeneman, Wijnand (mentor); Annema, J.A. (graduation committee); Oirbans, Leonard (mentor); Delft University of Technology (degree granting institution)","2024","Many cities are implementing car-reducing measures to achieve goals related to livability, such as climate change reduction, air quality improvements, improved living space, improved health and safety and reduced costs. Policies at the local, national, and supranational levels affect the measures that cities can take. This thesis addresses the challenges cities face in implementing car-reducing policies. Achieving the goals for which local governments are implementing car-reducing policies requires transformational adaptation. This system-wide radical change increases a system’s ability to deal with future uncertainty. However, it is challenging for policymakers to destabilize existing regimes. Answering governance questions related to context, power, resources, and legitimacy can help fill the research gap regarding real-world policy examples and aid in the transition towards sustainable mobility. This thesis proposes a framework based on theory and practice to address the challenges that policymakers may face in policy implementation.
The main research question is:
What success factors and barriers in the implementation of car-reducing measures are present in European cities, and what are the implications for European cities of the scale of Amsterdam?
Amsterdam is the reference case selected to contextualise the results of this thesis. Case studies in cities with comparable population sizes, namely Copenhagen, Barcelona, Bremen, and Milan, with considerable experience in car-reducing measures, provide new insights for policymaking. Understanding the context in which a policy operates has shown to be essential in its success and/or failure. The main barriers in the implementation are explored with stakeholders involved in policymaking.
Eight different success factors have been identified to overcome the barriers and successfully implement their policies. Six originate from the literature and were confirmed in the interviews. The two final
success factors of ‘the inarguability of schools’ and ‘the undeniability of hard evidence’, emerged during the interviews. These stakeholders identified the links between these factors and barriers, and how the success factors can reduce the barriers. The success factors of ‘showing openness and flexibility’ and ‘pilots/trials to create legitimacy’ can lower most barriers. Combined, these success factors can influence all barriers and are, therefore, most important.
The analysis of the case studies and the comparison with the literature results in lessons for cities looking to implement car-reducing policies. An in-depth analysis is performed for Amsterdam. Three main lessons of the studied cases stand out for Amsterdam. For other cities looking to implement car-reducing policies, four general lessons have been determined:
1. Continuously explore new possibilities for policymaking.
2. Be aware of the context and stakeholders’ needs to select appropriate measures and adjust them
according to the context.
3. Create and identify windows of opportunity and be ready when that window opens.
4. Test new measures before implementing them permanently to select the optimal location and
collect data on the measure’s impact.
The proposed framework of success factors and barriers can be used by policymakers to address the challenges they face in implementation. Using the framework and the lessons during the design of their policies, may significantly reduce the barriers they face and ensure successful implementation.","Low-car; Success factors and barriers; Case studies; Car-reducing measures; Policy analysis","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:6ceeddcd-10f5-4743-ad85-65dd9d7925d7","http://resolver.tudelft.nl/uuid:6ceeddcd-10f5-4743-ad85-65dd9d7925d7","Daylight control modelling with a multi-screen shading device: Case study on Museum Boijmans Van Beuningen in Rotterdam","Hamilton, Thijs (TU Delft Civil Engineering & Geosciences)","Schipper, H.R. (mentor); Pont, S.C. (graduation committee); Forouzandeh Shahraki, N. (graduation committee); Louter, P.C. (graduation committee); Franx, Laura (graduation committee); Delft University of Technology (degree granting institution)","2024","The museum Boijmans van Beuningen in Rotterdam is currently closed for restoration. The architect Van der Steur made an extensive study of lighting in museum rooms (1930). This resulted in a pitched roof with glass and a layer of horizontal glass panes (legramen) that form the ceiling of the exhibition rooms. Below the glass panes timber blades (schoepen) are placed under an angle to disperse the light.
The museum board wants to preserve the vision on daylight of Van der Steur and is now considering options for sun shading above the ceiling. This addition will allow them to better control the illumination in the museum and protect the artwork.
This Master thesis describes a method to assess the daylight exposure in the museum Boijmans van Beuningen. It can be used for a combined lighting design (daylight and artificial). The purpose of the method is to compare different sun shading solutions and their effects on the illuminance. A toolbox is made that can be used on other museums.
The method starts with a 3D model of one of the museum rooms. Alterations had to be made to accommodate the temporary renovation state. For the validation of the model, HDR images were made on-site. These results were compared with the calculation made with the 3D model. Iteratively the best possible fit was made.
With the validated model an hourly daylight simulation was done using the EPW climate-based weather data. The resulting illuminance exceeded the desired level at several points in time. Three different types of sunscreens were chosen. These were schematised as a continuous layer on top of the legramen. Based on the behaviour of the sun shading on three specific days, a daylight factor of 2% was found between the illuminance on the wall and the outside illuminance. With this relation and the EPW weather data the desired sun shading states for an entire year are predicted. A control mechanism is designed for the opening and closing of the sun shading based on local measurements. When the sun shading state changes, the illuminance can fall below the desired level of 125 lx. In that case, additional artificial lighting is needed. The calculations show that over an entire year, the total exposure is 469.286 lx·hr, this is a reduction of 82.2 % compared to the museum without any sun shading.
With the developed approach the user can gather building-specific characteristics and geometries, that include some form of ‘device’ that controls the top light entering a room. If the first part of the modelling process is done, and the hourly data is collected, the model behaves within the practically accepted limits that were set. This version can assess what selection of screens is effective, that will reduce the incoming light, without unnecessarily over-reducing it, and so limits the need for additional diffuse artificial lighting.
""If and to what extent can the analysis of indirect indicator be utilized to improve correlating ransomware attacks with cyber-threat actors?""
The research employs a mixed research approach. A literature review examines the techniques, indicators, and taxonomies used for attributing cyber-threat actors in general. Additionally, expert interviews explore differences in the attribution of ransomware threat actors compared to general cyber-threat actors. Furthermore, it highlights the need to use indirect indicators in the attribution process of ransomware threat actors. Therefore, a cybersecurity company's 2023 ransomware incident reports are analysed to understand how the ransomware attacks are investigated and how the conclusions are drawn.
This study identifies differences in attributing ransomware and general cyber-threat actors. While indirect indicators are crucial for attributing general cyber-threat actors, ransomware attackers often directly identify themselves through ransomware notes. These notes often provide access to communication channels and leak sites, offering substantial evidence for attribution.
The study also finds that Tactics, Techniques, and Procedures (TTPs) tend to be generic in ransomware attacks, offering limited value for differentiating between different actors. However, based on the interviews, there is a need for a central database of observed indirect indicators to facilitate future research and attribution efforts. Consequently, the research finds some promising results for using indirect indicators in ransomware threat actor attribution. The first finding is that the TTPs are less generic as initially thought as 32\% of the techniques and 47\% of the sub-techniques were unique. In addition, analysing the specific tools and techniques used by different actors, such as Blackcat's use of ""nltest"" for domain trust discovery, can help identify and differentiate them. Furthermore, threat actors observed only once in ransomware attacks of 2023 often used unique techniques, potentially allowing for differentiation based on this factor.
In conclusion, this study demonstrates that analysing indirect indicators can be a valuable tool in correlating ransomware attacks to specific threat actors. While certain limitations exist, continued research and development of this approach have the potential to significantly improve our ability to identify and track ransomware attackers.","Ransomware; Attribution; Cyber Threat; Ransomware Threat Actor","en","master thesis","","","","","","","","2025-04-03","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:41347a67-22e2-4fc9-a80a-5b82b50bd8f1","http://resolver.tudelft.nl/uuid:41347a67-22e2-4fc9-a80a-5b82b50bd8f1","Automated electrocardiogram interpretation for the detection of postoperative junctional ectopic tachycardia at the pediatric intensive care unit","Raaijmakers, Gini (TU Delft Mechanical Engineering)","van Twist, Eris (mentor); Bruining, Nico (mentor); Sylva, Marc (mentor); Delft University of Technology (degree granting institution)","2024","Background: Postoperative junctional ectopic tachycardia (JET) is an arrhythmia associated with increased morbidity and mortality rates in children with congenital heart disease. Developing an automated detection algorithm could aid in early identification and timely treatment of JET.
Methods: A retrospective study was conducted using monitor electrocardiogram (ECG) data of pediatric patients who experienced JET during their admission to the pediatric intensive care unit. A manual decision tree was developed that aimed to differentiate between JET and sinus rhythm based on distinctive characteristics. These features were derived using signal analysis on both two-dimensional vectorcardiograms and ECG data. For the latter, ECG metrics were detected in a fictive lead that was created in the direction with the highest amplitudes. Metrics were identified within adaptive intervals that were dependent on ECG morphology rather than relying on fixed time intervals.
Results: A classification performance was achieved with a sensitivity of 96.3%, specificity of 71.4%, positive predictive value (PPV) of 86.7% and an accuracy of 87.8%. R peaks, Q peaks, S peaks, T peaks and P waves were detected with an accuracy of respectively 99.9%, 95.7%, 89.7%, 98.1% and 54.8%. The computational time of the classification of 41 minutes of data was 4 minutes and 48 seconds.
Conclusion: A manual decision tree algorithm for JET detection was developed, using signal analysis for feature extraction based on JET characteristics. This method with a low computational time and a high sensitivity and PPV holds potential for clinical application as a bedside tool. Implementing this proposed algorithm would allow for treatment in an earlier phase, thereby potentially reducing JET associated morbidity and mortality rates.","Junctional ectopic tachycardia; Arrhythmia detection; Signal analysis; Decision tree","en","master thesis","","","","","","","","","","","","Technical Medicine | Sensing and Stimulation","TM30004; 35 ECTS",""
"uuid:270173e7-6ce6-4a71-ac42-79eab09cce5f","http://resolver.tudelft.nl/uuid:270173e7-6ce6-4a71-ac42-79eab09cce5f","Stress Evolution in Early-Age Cementitious Materials Considering Autogenous Deformation and Creep: New experimental and modelling techniques","Liang, M. (TU Delft Materials and Environment)","Schlangen, E. (promotor); Šavija, B. (promotor); Delft University of Technology (degree granting institution)","2024","Since the introduction of cementitious materials, shrinkage-induced earlyage cracking (EAC) has emerged as a significant issue that negatively influences the function, durability, and aesthetics of concrete structures like dams, tunnels, and underground garages. This thesis aims to develop new experimental and modelling techniques that help resolve this longlasting issue, with a particular emphasis on the EAC induced by AD (AD). Unlike the thermal and drying deformation which are induced by heat and moisture transport, respectively, the AD is an intrinsic behavior caused by the self-desiccation of the hydration of cementitious materials. The ADinduced EAC risk is especially high when it comes to modern (or future) cementitious materials, such as high-performance concrete, ultra-highperformance concrete, and alkali-activated slag concrete.","Early-age cracking; autogenous deformation; creep/ relaxation; Temperature-Stress-Testing-Machine; finite element model; machine learning","en","doctoral thesis","","978-94-6366-843-9","","","","","","","","","Materials and Environment","","",""
"uuid:db3c8752-12d2-41d8-84de-51c3cd3332c8","http://resolver.tudelft.nl/uuid:db3c8752-12d2-41d8-84de-51c3cd3332c8","Privacy: the more, the merrier?: A case study of how Amazon uses privacy protection to expand its power over IoT manufacturers","van Gend, Thijmen (TU Delft Technology, Policy and Management)","Bertulfo, D.J. (graduation committee); Gürses, F.S. (graduation committee); van Eeten, M.J.G. (mentor); de Reuver, Mark (graduation committee); Delft University of Technology (degree granting institution)","2024","Privacy-enhancing technologies (PETs) have historically been used for safeguarding individual privacy from both public and private interference. But lately, tech companies have started using PETs as one instrument for the expansion of their power over different actors, as appears to be unfolding in the case of Amazon’s Sidewalk service: a United States-only privacy-preserving crowdsourced service that promises connectivity to Internet of Things (IoT) devices manufactured by third parties in smart-home, logistics, and utilities use-cases. Compatible IoT devices (‘endpoints’) are granted connectivity by ‘gateways’, namely smart-home devices from Amazon’s Echo (smart speakers) and Ring (smart cameras and doorbells) series that donate a portion of their bandwidth to endpoints that might be owned by others. Amazon pushed a software update to these Echo and Ring devices, that turned them from smart-home devices to contributors to the Sidewalk network, unless users actively opted out, yielding a coverage of at least 90% of the US population. With Sidewalk, Amazon leverages PETs (namely end-to-end encryption and device identifier obfuscation) to mitigate privacy concerns that the crowdsourced architecture yields. However, this necessitates significant investments from third-party manufacturers to make their devices Sidewalk-compatible, suggesting a power emergence shaped by PETs.
I answered the research question “How does Amazon’s use of privacy-enhancing technologies in Sidewalk affect its power over IoT manufacturers?” by reviewing grey literature, analysing the Sidewalk technology, and elite interviewing with high-ranking employees of Sidewalk-adopting manufacturers. I have shown that Amazon leveraged PETs to mitigate public security concerns, but in the meantime reshapes how manufacturers produce their devices. Part of this ploy is cementing AWS in their production processes. Amazon also uses this leverage to mobilise manufacturers’ and silicon providers’ resources to improve Sidewalk’s public reception, technology, and governance.
These reconfigurations are expensive and complicated to realise, but manufacturers stressed the importance of Sidewalk adoption to leverage Amazon’s reputation vis-à-vis suppliers and customers, and “befriend the giant” for they rely on Amazon’s Marketplace, cloud, and logistics.
Meanwhile, Amazon’s reductionist framing of privacy and security as protecting user identity and data confidentiality, means that confidentiality of manufacturers’ business-sensitive information is not discussed. With this vantage point, Amazon can learn which endpoint types are popular and how they work; but Sidewalk might also be a vehicle for Amazon to attract more IoT developers to AWS.
In sum, I have demonstrated that strictly pursuing user privacy (or confidentiality) in digital services may have unforeseen effects on production. Therefore, I call upon privacy and competition scholars, advocates, and regulators to question how privacy protection actually augments companies’ power, and stepping away from their narrow “consumer harm” lenses. These actors should debate a right to personal control over devices. A mere consumer focus in studying these developments is insufficient: I established that business-to-business relations and businesses’ production processes are more significantly affected than consumers. The production focus of this work lays bare the novel power dynamics between Amazon and manufacturers, shaped by PETs.","privacy; privacy-enhancing technologies; power; case study; Amazon; production; cloud computing; edge computing; computational infrastructure; mesh networks","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","Programmable Infrastructures Project",""
"uuid:7fc13bf4-fc61-411a-8f60-0333cc255b4f","http://resolver.tudelft.nl/uuid:7fc13bf4-fc61-411a-8f60-0333cc255b4f","Synthesis and Verification of Neural Control Barrier Functions for Safe Reinforcement Learning with Guarantees","Wang, Sunny (TU Delft Mechanical Engineering)","Alonso-Mora, J. (mentor); Knödler, L. (graduation committee); Pek, Christian (graduation committee); Mathiesen, Frederik Baymler (graduation committee); Delft University of Technology (degree granting institution)","2024","While learning-based control techniques often outperform classical controller designs, safety requirements limit the acceptance of such methods in many applications. Recent developments address this issue through Certified Learning (CL), which combines a learning-based controller with formal methods to provide safety guarantees. This thesis focuses on the CL based on Control Barrier Functions (CBFs), as CBFs have been widely used for safety-critical systems. However, it is non-trivial to design a CBF. Utilizing neural networks as CBFs has
shown great success, but it necessitates their certification as CBFs. In this work, we leverage bound propagation techniques and the Branch-and-Bound scheme to efficiently verify that a neural network satisfies the conditions to be a CBF over the continuous state space. To accelerate training, we further present a framework that embeds the verification scheme into the training loop to synthesize and verify a neural CBF simultaneously. In particular, we
employ the verification scheme to identify partitions of the state space that are not guaranteed to satisfy the CBF conditions and expand the training dataset by incorporating additional data from these partitions. The neural network is then optimized using the augmented dataset to meet the CBF conditions. We show that for a non-linear control-affine system, our framework can efficiently certify a neural network as a CBF and render a larger safe set than state-of-the-art neural CBF works. We further employ our learned neural CBF to derive a safe controller to illustrate the practical use of our framework.","cbf; verification; safe learning","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:a45acef5-5ef9-4797-be5e-08498566ec8a","http://resolver.tudelft.nl/uuid:a45acef5-5ef9-4797-be5e-08498566ec8a","Wind turbine blade damage detection using aerodynamic noise","Zhang, Y. (TU Delft Wind Energy)","Watson, S.J. (promotor); Avallone, F. (promotor); Delft University of Technology (degree granting institution)","2024","Wind energy is one of the most important renewable energy sources, effectively addressing climate change issues and promoting sustainable development on a global scale. Blade failures may cause long shut-down times and may present a safety hazard. Continuous and real-time monitoring of the blade conditions is helpful for finding blade damage at an early stage and for predicting its development. Non-contact damage detection methods have the advantage of easy and flexible installation and deployment, especially for current in-service wind turbines. This thesis aims to investigate and develop a new non-contact method for wind turbine blade damage detection based on measurements of aerodynamic noise. The principle of the proposed method relies on the fact that damage to the blade may modify the boundary layer over the blade surface and the flow field around the blade, and, as a consequence, alter the noise generated aerodynamically. This noise propagates to the far-field and be measured by microphones, which could provide a remote way to detect blade damage. In this thesis, the detection of two types of damage, trailing edge crack and leading edge erosion, is experimentally investigated in the wind tunnel. The results show that the proposed aeroacoustics-based approach can effectively detect the damage mentioned above under some circumstances, which might be a promising solution complementing traditional damage detection methods in wind farms in the future.","wind turbine blade damage; aerodynamic noise; trailing edge crack; leading edge erosion; damage detection","en","doctoral thesis","","978-94-6384-556-4","","","","","","2024-04-03","","","Wind Energy","","",""
"uuid:5d444c43-0e3a-4912-838c-5a9c20ffee97","http://resolver.tudelft.nl/uuid:5d444c43-0e3a-4912-838c-5a9c20ffee97","Comprehensive Human Oversight over Autonomous Weapon Systems","Verdiesen, E.P. (TU Delft Information and Communication Technology)","Dignum, M.V. (promotor); Santoni De Sio, F. (promotor); Delft University of Technology (degree granting institution)","2024","","","en","doctoral thesis","","978-94-6496-075-4","","","","","","2024-04-04","","","Information and Communication Technology","","",""
"uuid:ae5b09c6-5e51-4c50-8fef-cd46d48b900d","http://resolver.tudelft.nl/uuid:ae5b09c6-5e51-4c50-8fef-cd46d48b900d","Distribution of water during drought","Poppe, Tim (TU Delft Technology, Policy and Management)","Klijn, F. (mentor); de Bruijne, M.L.C. (graduation committee); Mens, Marjolein (graduation committee); Delft University of Technology (degree granting institution)","2024","In recent years, the escalating frequency of droughts due to climate change has made the prospect of more frequent droughts increasingly tangible. Effective water management during these periods is paramount, as it involves balancing water demand with limited supply. Water distribution models are instrumental in this regard, aiding decision-makers in preparing for and mitigating the impacts of drought and water scarcity.
This study aims to investigate how water distribution models align with the interests of key stakeholders, particularly during droughts. Using the Quick Water Allocation Scan Tool (QWAST) by Deltares as a case study, the research explores how water is allocated during droughts in the Netherlands. Through literature review and stakeholder interviews, the study examines the values underlying stakeholders' water demands and their perspectives on water-related issues.
Four main sectors with distinct water demands are identified: agriculture, inland shipping, drinking water, and nature conservation. While efforts are made to balance water demand across these sectors, challenges arise during droughts when each stakeholder seeks to protect its interests. Despite the expectation of value conflicts, stakeholders generally acknowledge the need for balance.
However, closer examination reveals challenges in water allocation during droughts, particularly regarding the adequacy of QWAST. The tool primarily focuses on surface water, overlooking groundwater, which is crucial during droughts. Each sector has specific water quality and quantity requirements, leading to a complex set of claims and challenges in water allocation.
While stakeholders share overlapping values, QWAST is considered incomplete in addressing drought management and water distribution effectively. Stakeholders question its relevance as a water allocation tool, especially considering its limited coverage of groundwater. Instead, there's a call to prioritize groundwater management directly, particularly during drought situations.
Recognizing the disparity in perspectives, the study recommends integrating economic considerations and policy implications into QWAST. By quantifying the impact of drought on sectors, the tool's value for stakeholders can be enhanced. Additionally, initiating comprehensive discussions on water allocation, covering both surface and groundwater, is suggested to reach a consensus on addressing water scarcity effectively.
In conclusion, while water distribution models like QWAST offer valuable insights, they fall short in addressing the complexities of drought management and water allocation, particularly regarding groundwater. Integrating economic perspectives and policy considerations can enhance the effectiveness of such models in guiding decision-making during periods of water scarcity.","","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:4a1519ba-3542-4d8f-ab91-2342e8f5bb1a","http://resolver.tudelft.nl/uuid:4a1519ba-3542-4d8f-ab91-2342e8f5bb1a","Understanding Adversary Behavior via XAI: Leveraging Sequence Clustering To Extract Threat Intelligence","Nadeem, A. (TU Delft Algorithmics)","Lagendijk, R.L. (promotor); Verwer, S.E. (promotor); Delft University of Technology (degree granting institution)","2024","Understanding the behavior of cyber adversaries provides threat intelligence to security practitioners, and improves the cyber readiness of an organization. With the rapidly evolving threat landscape, data-driven solutions are becoming essential for automatically extracting behavioral patterns from data that are otherwise too time-consuming to discover manually. This dissertation advocates the use of machine learning (ML) to obtain insights into adversary behavior for creating AI-assisted practitioners. However, developing adversary behavior models is challenging since cyber data is often unlabeled, noisy, infrequent, and contains intricate patterns that evolve over time. We demonstrate that sequential features are effective at addressing these challenges. Yet, they have limited interpretability and algorithmic support.
This dissertation starts by defining the notion of explainability as it is currently used within cybersecurity by systematizing available literature in Chapter 2. We find that the literature frequently relies on black-box models that use off-the-shelf explanation methods without considering the explanation stakeholders. In contrast, literature on sequence learning models that are interpretable by design is severely limited.
We address these challenges by developing special algorithms that learn sequential patterns from infrequent events, and evolving data in an unsupervised setting. We utilize these algorithms to create interpretable tool-chains for understanding the behavior of various types of adversaries. We show that it is possible to learn interpretable models (even for complex sequential data in an unsupervised setting) that provide more insights than just prediction probabilities, while achieving competitive performance. In doing so, we encourage the security community to look beyond accuracy scores, and focus on extracting actionable insights from ML models. We make our tool-chains open-source.
The first part of this thesis models the strategies employed by human threat actors. Chapters 3 and 4 develop a novel paradigm of attack graphs (AG) that are learned directly from intrusion alerts for capturing attacker strategies. The attacker strategies are learned using our S-PDFA model, which is interpretable, fast, and effective. We learn alert-driven AGs from 3 open-source datasets, and show their ability to compress over 1.4 million alerts in 401 AGs in under 5 minutes. The AGs provide actionable intelligence regarding strategic differences and fingerprintable paths. They also reduce analyst alert fatigue by triaging critical attacks.
The second part of this thesis models the capabilities exhibited by automated threat actors (malware). Chapters 5 and 6 develop an explainable sequence clustering tool-chain to automatically characterize the network behavior of malware samples. We use this tool-chain to create behavioral profiles of 1196 real-world malware samples for explaining their capabilities. We also develop a streaming sequence clustering algorithm for real-time behavior profiling, which is evaluated on 5 datasets and against 4 clustering algorithms. By automatically creating behavioral profiles of bot-infected hosts in real-time, we distinguish benign and malicious hosts with 100% accuracy.","Cybersecurity; Explainable machine learning; Behavior modeling","en","doctoral thesis","","978-94-6366-828-6","","","","","","","","","Algorithmics","","",""
"uuid:3f2cad24-d7f5-4b19-9630-9f40207275ec","http://resolver.tudelft.nl/uuid:3f2cad24-d7f5-4b19-9630-9f40207275ec","Research on Urban Heritage Values based on the UNESCO Historic Urban Landscape (HUL) Approach: The case study of Suzhou","Huang, H. (TU Delft History, Form & Aesthetics)","van Thoor, M.T.A. (promotor); Hein, C.M. (promotor); Delft University of Technology (degree granting institution)","2024","As far as a historic city is concerned, a city is a dynamic complex which consists of many different interrelated and interactive elements. It is unreasonable to assess urban heritage by using a single value category. The evaluation of urban heritage values needs to develop a theoretical framework to represent the relationships between different elements. In view of the above issues, there is so far still a lack of systematic study on urban heritage values in Chinese academic circles. Therefore, it is necessary to construct the value system of urban heritage by adopting a scientific method.
This study aims to build up an integrated value system to facilitate the identification of urban heritage values, so that the complexity of urban heritage values is revealed through connections of different elements. The research work includes theoretical construction and a case study. First, the HUL is interpreted as a method of spatialtemporal scale by discussing the philosophical framework of HUL. Based on this finding, the gap between HUL at the operational level and the heritage value theories is filled. Second, as a case study, the analysis of the ancient city Suzhou is a verification of the value system of urban heritage in the practical sense. It also proves that the constructed value system is reasonable and achievable for urban conservation in the Chinese context.","historic urban landscape; spatial-temporal scale; ynamic and structural value system","en","doctoral thesis","A+BE | Architecture and the Built Environment","978-94-6366-836-1","","","","","","","","","History, Form & Aesthetics","","",""
"uuid:a24dac77-8bfd-4850-826b-c99fa5a7ace2","http://resolver.tudelft.nl/uuid:a24dac77-8bfd-4850-826b-c99fa5a7ace2","Dynamic laser speckle imaging for velocimetry in blood flow: A numerical study","van As, K. (TU Delft ChemE/Transport Phenomena)","Kenjeres, S. (promotor); Kleijn, C.R. (promotor); Bhattacharya, N. (promotor); Delft University of Technology (degree granting institution)","2024","Cardiovascular diseases are one of the leading causes of death worldwide, for example by causing strokes. Timely diagnosis of such diseases is pivotal for a patient’s chance of survival. Furthermore, in the present world in which medical expenses are going through the roof, we can save greatly on costs if certain diseases are detected in an earlier stage. To that end, our research is focused on improving medical measurement techniques, to give doctors a greater arsenal to combat these diseases.
Ideally, a measurement technique is cheap, accurate, and all while causing minimal discomfort to the patient. Light-based techniques have proven previously to have great potential to fulfil that role. For example, that tiny device that you can put on your finger, and similarly the sensor in a sports watch, are able to measure your heart rate using light. For our research we have developed a computer model, such that we can use the power of modern computing. Our model is able to predict how light is reflected by red blood cells flowing through an artery. The computer is then able to rapidly simulate many scenarios, producing a lot of data about what the reflected light looks like for each scenario. From that data, we are able to say something about what a certain pattern in the reflected light says about the underlying system: the flowing red blood cells.
As a first step, we have used our model to figure out how we can determine the heart rate from the reflected light. You could argue that that’s nothing special, as your sports watch can already do precisely that, but it’s an important step nonetheless, since our technique is different than what your sports watch is doing. Namely, the data our technique provides is more complex, but as a consequence also contains much more information and thereby yields a greater potential if we just become able to extract that information from the data.
Therefore, our second step was to determine the exact velocity of the red blood cells from the reflected light, which is quite of a magical thing when you think about it: even though we cannot ‘see’ the red blood cells directly, we can still ‘see’ how fast they are moving. Although we succeeded in determining the velocity, in reality a doctor will likely need to do some tweaking to account for patient-specific factors, such as skin tone.
Finally, we studied the disease atherosclerosis, in which accumulating cholesterol causes arteries to become more narrow, which ultimately could lead to a stroke. The narrowing of an artery, alters the flow behavior of the red blood cells, which we were able to pick up by studying changing patterns in the reflected light from our simulations. By extension, it should be possible to use reflected light to detect atherosclerosis, rapidly and cheaply flagging patients who are at risk.
We have shown the potential of reflected light techniques for medical diagnosis purposes. Although further research and work is still required to put these techniques into practice for doctor’s to use, we have set the groundwork to enable these techniques in the not-too-distant future.
After the software is tested and the results validated, different stages of the service life of a transition zone (new - used - heavily used) are simulated. From the results two main conclusion can be drawn. First, the vertical acceleration is able to show the changes in differential settlement and stiffness that are occurring at transition zones. The indicators for these changes are the frequency responses with a wavelength between 1.2 < 𝜆 < 5 meters. This shows that ABA is a powerful non-invasive monitoring technique for long wavelength track irregularities. Second, the multi body simulation software is able to model complex railway tracks. The software shows the same characteristic frequencies as the measurement data does.
The results of this investigation could especially be of interest for asset owners and contractors. By showing that ABA measurements tends to be an effective way of monitoring transition zones, predictive maintenance could be implemented which saves time and high costs.","Axle Box Accelerations; Multi body simulation software; Railway transition zones; VI-Rail","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:267fd3ff-3ca0-42b5-97a0-ca571dcbb6be","http://resolver.tudelft.nl/uuid:267fd3ff-3ca0-42b5-97a0-ca571dcbb6be","Assessing perceived Humanness of Artificial Intelligence in Chess: A Turing Test experiment using Think Aloud and Eye Tracking methods","Koerts, Robin (TU Delft Mechanical Engineering)","Eisma, Y.B. (mentor); de Winter, J.C.F. (mentor); Dodou, D. (graduation committee); Delft University of Technology (degree granting institution)","2024","With the advancement of Artificial Intelligence leading to increasingly human-like outputs, assessing a machine’s ability to exhibit human-like intelligence has become more essential than ever. This study aims to investigate how human-like chess players perceive four conditions: one human opponent and three different types of algorithms. One of these algorithms, Maia, has been trained on human data and aims to play the most human-like move. In a custom-designed experiment similar to a Turing test, chess players faced off against Maia, Stockfish and a human without knowing their opponent’s nature. After each game, the chess player assessed how human-like the moves of the opponent were and estimated whether they played against an engine or a human opponent. During the game, participants were asked to think aloud about their next move and react towards the moves of the opponent. Additionally, the gaze of the player was captured with the SR EyeLink Portable Duo at 1000Hz, with the goal of finding differences within the player’s gaze while participants tried to discover the nature of their opponent. Results from the experiment revealed that, based on responses to a subjective questionnaire, the perceived humanness of Maia is statistically similar to a human and different from the other two chess engines. From the analysis of the voice recordings, categories of sentences were identified that could suggest recognition of the opponent, specifically: ""expected"", ""unexpected"", ""human-like"" and ""engine-like"". From the eye-tracking results, the average fixation duration and pupil diameter changes following the opponent’s move were compared for each condition, but showed no statistical differences between conditions. In summary, Maia was perceived more human-like compared with other chess engines. However, differences in underlying cognitive processes on how the human perceived this difference in a Turing Test experiment were not identified.","Chess; Turing Test; Chess dataset; Artificial Inteligence; Human Robot Interaction","en","master thesis","","","","","","","","","","","","Mechanical Engineering | BioMechanical Design","",""
"uuid:b3bb6e24-4deb-44dc-af0b-410dc0f9864a","http://resolver.tudelft.nl/uuid:b3bb6e24-4deb-44dc-af0b-410dc0f9864a","Fostering collective self-reliance in elderly care: A value-based approach to the intake conversation in homecare at Surplus","van Alkemade, Ianthe (TU Delft Industrial Design Engineering)","van der Bijl-Brouwer, M. (graduation committee); de Vos, Marina (mentor); Delft University of Technology (degree granting institution)","2024","This project responds to the increasing challenges in Dutch elderly care amid an undeniable ageing demographic. Between now and 2040, the number of individuals aged 80 and over will nearly double, and one in four people will need to work in the healthcare sector to satisfy the increasing demands.
The current system of elderly care is very much solution-focused, where professional caregivers often provide the answers and lead the discussions. Organisations like Surplus, a care and welfare organisation in West Brabant, struggle to continue to meet the expectations of (new) clients and their relatives, placing an additional burden on professional caregivers.
The increasing pressure highlights a need for greater autonomy and shared responsibility in elderly care. The urgent and multifaceted nature of the current challenges calls for a ‘new way’ of caring, with a greater reliance on answers from society. This project envisions a shift towards a caring society that focuses on what is still possible rather than on limitations, aiming for a meaningful life. Where self-reliance is a collective effort, and each individual is truly recognised.
Through a systemic design approach, this project seeks to navigate these challenges by uncovering key personal values in receiving and providing care and mapping out the elderly care system to identify opportunities to intervene. An intervention that incorporates these values is designed to initiate a shift towards the desired direction.
To facilitate this change, I have developed a new approach for Surplus to have value-oriented conversations, to match what we find important in life. Inviting people to think beyond the care question and to look together at what is possible instead of what is no longer possible. Transitioning from a traditional “intake” in home care to “acquaintance”, it introduces the T-Doos (Tijd voor gesprek, Thee voor twee, Langer Thuis: Time for Conversation, Tea for Two, Staying Home Longer) personal preparation package with a conversation box and a conversation framework. This invites the elderly in need of support to think together with their informal carers about what is important to them in daily life, who they are in contact with, what makes them happy and how they look ahead. It sets the stage for meaningful discussions with district nurses to collaboratively explore possibilities. The professional caregiver adopts a coaching role, and a transition is started in mindset and practice within care organisations and among healthcare professionals.","elderly care; value-based care; systemic design; collective self-reliance","en","master thesis","","","","","","","","","","","","Strategic Product Design","",""
"uuid:80ac2796-4a89-4935-8119-39c71230d876","http://resolver.tudelft.nl/uuid:80ac2796-4a89-4935-8119-39c71230d876","Solvent-free approach for processing hybrid solid electrolytes","Macray, Laurence (TU Delft Electrical Engineering, Mathematics and Computer Science)","Wagemaker, M. (mentor); Ganapathy, S. (mentor); Bouwman, W.G. (graduation committee); Zhang, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","An all-solid-state battery represents a promising solution for overcoming current lithium-ion batteries ’technological and safety limitations. However, the individual limitations of both inorganic and organic solid electrolytes hinder technological progression. Hybrid solid electrolytes hold the potential to surpass these limitations by integrating both the inorganic and organic phases. A comparative assessment was conducted between hybrid solid electrolytes produced via solvent and dry synthesis, to address potential solvent interactions during hybrid solid electrolyte production and prioritise sustainability.
At 30°C, the comparative analysis demonstrates that the dry-processed PEO13LPSC10 hybrid solid electrolyte achieves a higher ionic conductivity of 1.61×10−5 S/cm, exceeding that of its solvent pro-cessed counterpart, which exhibits a conductivity of 1.51×10−5 S/cm. Conversely, for the PEO18LPSC10 hybrid solid electrolytes, the solvent processing method leads to a higher ionic conductivity, measured at 8.37×10−6 S/cm, in contrast to 7.61×10−6 S/cm observed for the dry-processed method. Thermal analysis indicates that heating above the polymer’s melting transition temperature leads to slow crystallisation in hybrid solid electrolytes using the dry method, resulting in two crystalline phases, as opposed to the single crystalline phase, which was observed using the solvent method. Both processing methods demonstrate homogeneity when comparing the top and bottom surfaces; however, an analysis of surface compositions between the two synthesis methods reveals distinct differences, as identified through. X-ray photoelectron spectroscopy. Moreover, decomposition is observed in both synthesis approaches but is more significant in solvent synthesis. The chemical stability of hybrid solid electrolytes produced by dry synthesis surpasses the solvent-based method.
Further analysis through the dry method investigation reveals that an ethylene oxide to Li+ ratio of 10:1, and a Li6PS5Cl ratio of 10 wt%, yield the highest ionic conductivity among all studied hybrid solid electrolytes. This combination achieves an ionic conductivity of 3.35×10−5 S/cm at 30° C. Additionally, adding Li6PS5Cl and the alkali salt lithium bis(trifluoromethanesulfonyl)imide enhances the amorphous nature and mobility of the polymer, due to a plasticising effect on the organic matrix.
In this work, we propose EON-1, an Edge ONline Learning SCNN (Spiking Convolutional Neural Network) processor with 1-bit synaptic weights, 1-spike per neuron and 1-neuron updated per input, which we have benchmarked for both ASIC and FPGA platforms. Our key contribution is proposing a binary and stochastic SDTP rule which, benchmarked in an ASIC node, achieves less than 1% energy overhead for inference. To our knowledge, our solution incurs the least energy overhead for inference, compared to state-of-the-art solutions, showing a better efficiency by at least a factor of 10x. We also report 94% and 77.65% accuracy on the MNIST and Fashion-MNIST classification tasks, and we achieve 0.09pJ/SOP and 1.5pJ/SOP energy efficiency during inference and learning, respectively. We extend our solution to demonstrate a practical use-case of performing inference in real-time UHD videos while coping with streaming data and we showcase 60 FPS UHD video processing.","Brain-Inspired; SNN; edge AI; Efficient Feature Extraction; Online Learning; On-device Learning; binary STDP; stochastic STDP","en","master thesis","","","","","","","","2025-03-29","","","","Computer Engineering","",""
"uuid:21090579-3843-4769-8ce8-bde17e515355","http://resolver.tudelft.nl/uuid:21090579-3843-4769-8ce8-bde17e515355","Thermal Energy Storage for Industrial Applications","Gelling, Pauline (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Process and Energy)","Hooman, K. (mentor); Delft University of Technology (degree granting institution)","2024","The growing consumption of fossil energy resources increases greenhouse gas emissions (GHG). To meet the industry sector's target of reducing GHG emissions by 49% in 2030, relative to the levels in 1990, there is a need for energy storage. Energy storage offers a potential solution to enhance the utilization of renewable energy, by addressing the intermittent nature of these sources. This study includes a conceptual design for three Thermal Energy Storage (TES) materials, steel slag, phase change salt, and molten salt, able to generate steam in the industry (4-20 bar). Moreover, this study attempts to contribute to faster commercialization of the phase change materials, by aiming to contribute to a thermal conductivity improvement method. The thermal conductivity limits the discharging and charging ranges nowadays.
The concept designs are based on a fluctuating steam demand pattern provided by Arcadis. Two storing modes are extracted, a stand-alone thermal energy source which can meet a 12-hour steam demand and an energy source intended for peak shaving. Based on literature, the storage configurations, with the associated key parameters are extracted, for each material, to attain an estimation of the dimensions and losses. Due to the inflexibility of literature on phase change salt, a semi-empirical model is developed. With this model, the temperature of the heat transfer fluid (HTF) temperature at the outlet of the storage can be calculated based on various input parameters. The input parameters include the type of phase change salt, type of HTF, mass flow rate of the HTF, and the dimensions of the storage. The HTF outlet temperature in combination with the mass flow determines the discharge power. Based on the output of the TES, an economically optimized design, of a shell and tube steam generator, using AspenEDR software, is conducted.
The results for the stand-alone case showed almost similar volumes for the steel slag and phase change salt. The molten salt storage solution was larger based on the requirement of two tanks, a hot and a cold one. Furthermore, phase change salts resulted in the highest total stored energy, which is a measure of the inability to completely discharge the phase change storage in combination with a maximum temperature drop of the HTF outlet temperature. An increase in the thermal conductivity of the phase change salt can reduce this problem. Another advantage is the possibility of using any HTF for charging and discharging the phase change salt. Due to diffusion inside the TES upon partly charging and discharging, steel slag and phase change salt seemed not suitable for peak shaving.
Next, the focus is on increasing the thermal conductivity of the phase change salt. A readily available, stainless steel, wire mesh implemented in the phase change salt, at the shell side of a shell and tube storage, already yields a 10% increase in overall discharging performance. A graphite coating, applied on the mesh, could enhance the corrosion resistance, thereby enabling the the use of a higher conductive steel, such as carbon steel. Furthermore, could a graphite coating increase the overall thermal performance, by generating highly conductive pathways parallel to the mesh. A suitable graphite coating is obtained by exploring graphite coatings in various application areas. Together with the requirement of this coating, the first choices are made regarding the components of the coating. In addition, various experimental results are conducted to determine a potential coating composition and application method.
Results showed that a graphite coating consisting of graphite, Polyvinylidene Fluoride (PVDF) and N-Methylpyrrolidone (NMP), applied with the use of a dip coater, followed by drying, could be attached to the carbon steel with a thickness of 2 mm in four layers. The influence of the graphite coating is estimated with the use of a resistance model.
Further research should focus on quantitatively determining the influence of the graphite coating application in combination with the evaluation of the corrosion resistance of the coating.","Thermal Storage; Industrial application; Phase Change Material (PCM)","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:2c11c923-56dc-4b50-8544-fe899ef3f933","http://resolver.tudelft.nl/uuid:2c11c923-56dc-4b50-8544-fe899ef3f933","Congestion Detection Through Velocity Estimation Using a Monocular Camera","Baltus, Jelle (TU Delft Mechanical Engineering)","Grammatico, S. (mentor); Delft University of Technology (degree granting institution)","2024","This thesis report aims to answer the following research question: “Is it possible to estimate relative velocities of vehicles surrounding the ego vehicle using a monocular camera with such an accuracy that meaningful conclusions can be made about the current traffic state?” To answer this question, a velocity estimation algorithm is developed in three major parts: object detection, object tracking with detections and velocity estimation using tracked 2D objects. For the detection part, a version of the YOLOv3 (You Only Look Once version 3) single shot detection neural network is used. For object tracking with detections, the Simple Online and Realtime Tracking (SORT) algorithm is used. The last part, velocity estimation using tracked 2D objects, a state-of-the-art method using a neural network is compared to a novel proposed method, using a 2D to 3D map in combination with a kalman filter using a constant velocity model. The results of the detection and tracking parts were good enough to reason that they are used as a base of the velocity estimation algorithm. When comparing the-state-of-the-art velocity estimation algorithm and the novel approach, the errors of the novel approach were significantly higher, and the results of the state-of-the-art methods could not be replicated. This means that the research question of this thesis can be answered with yes, it is possible to estimate relative velocities of surrounding vehicles, however the resulting estimation errors are too high to make meaningful conclusions about the current traffic state.
The proposed approach is based on a graph-time convolutional neural network (GTCNN) that relates available PMU measurements inside the distribution network on a graph structure 𝒢GTCNN. The graph 𝒢GTCNN is obtained by taking a modified line graph of the graph representation of the power system and is expanded using the Cartesian product graph rule to include the temporal dependencies of nodes on their past values. The inputs of the equivalent model are the voltage magnitude |V| and angle θ at the PCC and the initial power injections P0 and Q at non-PCC nodes, while the model outputs the active P and reactive Q power at the PCC nodes. The GTCNN explicitly considers the initial power injections P0 and Q0 at non-PCC nodes to help the model learn how different operating conditions and topological changes impact the dynamic response. The DSO trains the equivalent model using simulation data or collected PMU measurements. The model is exchanged with the TSO every month, who can use the equivalent in co-simulation with their transmission network model to perform transient stability studies.
The GTCNN-based equivalent model showed promising performance as an equivalent model for transient stability. The GTCNN was benchmarked against two state-of-the-art Long Short-Term Memory (LSTM)-based equivalent models and a hybrid GTCNN-LSTM model. The evaluation was performed on a real Dutch distribution network using three datasets, each focussing on a different system condition: different fault events, different operating conditions and different hidden topological changes. The GTCNN-based equivalent model had a mean-squared error (MSE) below 0.02 for each dataset, which means it can accurately reproduce the dynamics. This accuracy is comparable to the LSTM-based equivalent models, but the GTCNN could train 4x faster. The GTCNN also showed good generalisation performance, as its accuracy did not decrease on the validation and test sets. A study on scaling performance suggested that the MSE of the GTCNN-based equivalent model increases slower than that of the LSTM-based models while its training time increases faster. Therefore, the GTCNN-based equivalent model trains faster for smaller ADNs but will be more accurate with more measurement nodes. However, the proposed GTCNN has difficulty learning the response at different close-by PCC terminals if the dynamics are different.
The developed GTCNN-based equivalent model can predict the dynamic response accurately under changing topologies and operating conditions at a similar performance level to existing LSTM-based approaches. However, its training time is much faster, which can result in a more accurate equivalent model by a more frequent model exchange between the DSO and TSO or a more extensive dataset being used to train the model. In future research, the GTCNN performance will be evaluated on a more comprehensive dataset containing all three system conditions to establish how much data is needed to train the equivalent model accurately. Also, the system frequency will be considered as an additional input. Moreover, its scaling performance will be evaluated more extensively and with a more efficient coding implementation. Furthermore, a heterogenous graph convolutional operator will be implemented to learn the connection per relational type (source node - edge type - target node). Finally, the co-simulation interface between the equivalent model and popular simulation tools will be explored.
The aim of the project is threefold:
Create social impact in the domain of value exchange in the public space of Kampala,
Apply the Vision in Product design (ViP) method for the first time in the designer’s career and
Evaluate the responsibility of the designer in relation to a cross-cultural design project.
After establishing the ViP domain as ‘value exchange in the public space’ and performing two deconstructions (one by the designer and one by Dwb) extensive research is performed.
It focuses on a time 10 years ahead (2034) and collects 215 factors (statements about the domain): 161 from literature, and 54 from interviews with 35 vendors in Kampala. The factors are clustered into 16 driving forces of the future context.
With the driving forces a framework is constructed of 12 cells, the directions the future context can move into. The axes of the framework reveal the root of the problems around street vending.
(1*) the organization of public space: Kampala’s public space receives meaning from many, misaligned origins. Government planning is not consistent with the use of space.
(*2) socio-economic uncertainty: the sheer numbers of people combined with a lack of jobs creates uncertainty to which people react in different ways. These reactions create their motive to participate in value exchange.
3 cells are chosen to formulate a vision statement. We want to decrease discrimination, provide stability for hustlers and steer investments to where they are needed. Three goals which correspond to the main stakeholders: vendors, clients and the local authority (KCCA). The lost in translation between them must be addressed to enable any social transformation. Integration of vendors must become the goal rather than expulsion. To achieve this we want to reveal the value of value exchange: showing vendors’ contribution in terms of convenience, urban life and economic potential.
With individual and group ideation the concept is developed. It consists of a stall and street design assigning space to vendors in pedestrian zones. Vendors are given fixed categories, streets are replanned and vendors are made the guardians and cleaners of the street. Placement of spots is used to regulate traffic flow and decongest the city. The concept couples this reorganization of public space to the other axis of socio-economic insecurity, by turning street vending from a last resort into a first step up the formal ladder. Vendors can only rent a stall for six months during which they are educated, build a network and are helped in saving money – after the 6 months they are ready to start a full business. The financial and organizational aspects of the concept are also thought out.
Elaborate testing is performed with vendors and authorities. Most of the feedback is worked into the concept. Recommendations for further development include directions for stall design and a road map for taking the concept to a pilot level.
The reflection results in 6 design principles guiding western designers doing projects in radically different contexts.
Current practice of Siemens Gamesa Renewable Energy (SGRE) is to perform aeroelastic simulations in their computational tool BHawC. The Foundation Designer delivers a foundation Superelement to maintain secrecy. The equation of motion for the jacket foundation can then be solved linearly with a reduced amount of unknowns. However, prevalence of nonlinearity in soil raises the question to what degree a linear model adequately captures the response.
This study investigates the impact of soil nonlinearity on OWT dynamic behavior under seismic loads by comparing linear and nonlinear soil models. The analysis involves performing seismic simulations using multiple earthquakes. Another distinction is made through soil models with different characteristics. Nonlinearity is introduced to the soil stiffness and energy dissipation mechanism under cyclic loading. The investigated variations are a linear (elastic), geometrically nonlinear (nonlinear elastic) or both geometrically and physically nonlinear soil model (nonlinear plastic).
The numerical model consists of a Rotor Nacelle Assembly (RNA), tower, transition piece, jacket, piles and soil springs. Beam elements are used for the tower, jacket and piles. The transition piece is simulated by stiffening the top jacket braces. The RNA is modelled using a lumped mass with rotational inertia. It is vertically eccentric to the tower top and connected with a rigid link. The earthquake is applied uniform over depth and only horizontal movements are considered.
The findings underscore a difference in results between the linear and nonlinear models. The evaluated results from simulations consist of forces, displacements and dynamic characteristics of the structure. Also noted should be that the computational time of the linear model is significantly lower. The results found in models can differ greatly due to the loading spectrum with highly varying frequency peaks. Another factor is softening of the stiffness. The frequency domain of the elastic model results consists of narrow peaks at the system's natural frequencies. The peaks for the nonlinear elastic model are wider due to softening of the stiffness. For the structure used in this research, softening introduces coupled modes with greater displacements along the height of the structure. This makes it possible for the evaluated results to have higher values, even with less energy put into the system. The plastic models' peaks are of a width in between the elastic and nonlinear elastic model due to the combined use of isotropic hardening and nonlinear stiffness. When the model falls back on its initial stiffness upon unloading, the eigenfrequencies related to that stiffness become more pronounced. To match the occupancy of wider frequency peaks, loading and unloading should both happen nonlinearly. This can be achieved by using kinematic hardening instead of isotropic hardening. Plasticity generally reduces peak displacement and sectional moment values and nonlinear stiffness broadens the response frequency spectrum. Careful consideration of cyclic material behaviour, eigenfrequencies and loading characteristics are essential for a realistic model.","nonlinear soil; Offshore wind turbine; Jackets; Earthquake analsyis","en","master thesis","","","","","","","","2024-03-21","","","","Civil Engineering","",""
"uuid:199fec66-490c-4d05-9d27-ac2f69dadad4","http://resolver.tudelft.nl/uuid:199fec66-490c-4d05-9d27-ac2f69dadad4","Raising the acceptance for a preference-based design methodology in the context of urban development","Raaphorst, Tomas (TU Delft Civil Engineering & Geosciences)","Binnekamp, R. (mentor); Kammouh, O. (graduation committee); Janssen, T.M.L. (graduation committee); Nan, Patrick (graduation committee); Delft University of Technology (degree granting institution)","2024","In the field of urban development few challenges are as tough as the housing problem. The cause for this is the rapid expansion of urban populations combined with slow construction processes. The Open Design Systems (Odesys) methodology is a preference-based design methodology for creating and evaluating designs. For this it uses a-priori method of optimization, where the preferences of stakeholders for each project objective are determined in the beginning of the process. Designs are thereafter created based on these preferences. Central to the success of preference-based design is the attitude of stakeholders towards using the methodology, which in other words is acceptance for this methodology. How can acceptance be evaluated? To do this the Technology Acceptance Model (TAM) was used. The system design features in the TAM were categorized in the “Use”, “Functionality” and the “Presentation”. Modifications to the Odesys methodology were made in these categories to see the effect on the stakeholder acceptability using the TAM. This research attempted to raise the acceptability for the Odesys methodology with the use of 2 case studies. The conclusion was that for the “Use” category the acceptability was dependent on the project design phase and the involvement of stakeholders. For the “Functionality”, the result reliability and the running time were important factors. The “Presentation” category consisted of the interface and the distinction between group and individual sessions. Modifications to these were developed and tested. This resulted in an increased perceived usefulness and a perceived ease-of-use , which according to the TAM results in an increased acceptance.","Preference; Acceptance; Optimization","en","master thesis","","","","","","","","","","","","Civil Engineering | Construction Management and Engineering","",""
"uuid:d21f1ee7-5e4d-4336-9664-fe6a41de8d7b","http://resolver.tudelft.nl/uuid:d21f1ee7-5e4d-4336-9664-fe6a41de8d7b","Aesthetic durability & Repair","4598865, Nr. (TU Delft Industrial Design Engineering)","Filippi, M. (mentor); Flipsen, Bas (graduation committee); Delft University of Technology (degree granting institution)","2024","Each year, over 50 million tonnes of electronic waste is generated globally, with the Netherlands averaging more than 20 kg per capita (Compendium voor de Leefomgeving, 2023). The shift from a linear to a circular economy is crucial in addressing this issue, emphasizing the importance of durability and repairability in product design. Additionally, the forthcoming legislation from the European Commission (2023) regarding the “right to repair” highlights the need for designers to create products that are both durable and repairable. This project delves into a product’s durability, considering not only its physical repairability, but also how it can retain aesthetic value over time. Central to this exploration is the question: “How can appliances be re-designed for retainment, considering repairability and aesthetic durability?” Drawing upon literature research, a design space is formulated, guiding the several re-designs of the same appliance, in this case a sandwich maker, with each re-design focusing on a specific aspects of repairability and aesthetic durability theory. Evaluation of these re-designs by visitors at Dutch Design Week informed challenges, guiding the further development of one of the re-designs into a functional prototype. The literature review addresses repairability through the challenge of fault diagnosis, particularly as products are often perceived as ‘black boxes’. Practical design implications for improving ease of disassembly and part replacement, alongside the value of awareness of components in having a product repaired, are discussed. Aesthetic durability is explored from the perspectives of ‘living with things’ and the ‘life of things’. The former examines aesthetic pleasure from a multisensory point of view, and the role of familiarity and novelty in design. The latter discusses the dimension of temporality in product design throughout a product’s lifetime, and the concept of products becoming ‘things’ when they break down. The construction of a design space with three axes based on this theory—’the possibility to repair’, ‘our pleasure as users’, and ‘the life of the thing itself’—provides a framework for creating eight diverse prototypes reflecting various perspectives from the theory. Evaluation by 3010 Dutch Design Week visitors identifies one prototype, featuring an ‘oven mitt’-like top, as standing out for its emotional qualities such as ‘connection’ and ‘beauty.’ This re-design is selected for further development into a functional prototype, highlighting repairability improvements and offering the opportunity for ergonomic testing.","Aesthetic durability; Repair; Re-design; Design for retainment; Emotional attachment; Circular Product Design; Aesthetic pleasure; Temporality; Thingness","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:f41c4c7e-6389-443f-a102-cb0eb9bc65c1","http://resolver.tudelft.nl/uuid:f41c4c7e-6389-443f-a102-cb0eb9bc65c1","Predicting and Interpreting Bipartite Temporal Networks","Mironov, Stas (TU Delft Electrical Engineering, Mathematics and Computer Science)","Wang, H. (mentor); Kooij, Robert (graduation committee); Delft University of Technology (degree granting institution)","2024","A network, is defined as a collection of nodes interconnected by links. When this topology changes through time, we call it a temporal network. A specific class of networks, with only two types of nodes with no connections between one kind, is the bipartite network. An example is a telecommunications network, where nodes represent telecommunication base station and various mobile services like web-browsing, streaming etc. A link may exist only between a base station and a service. Moreover, each link is associated with a time-evolving weight, which represents the volume of the traffic between the corresponding base station and service over time. This weight associated with each link is also called the activity weight, with the link considered active only when the weight is non-zero. Predicting such a temporal weighted network in the future is crucial for telecommunications engineers, allowing for e.g., better traffic management. Prediction of the unweighted temporal network one step ahead, at time $t+1$, based on the network observed in the past between $[t-L-1; t]$, has been studied recently in contact networks. However, the prediction of weighted temporal networks, or equivalently, predicting the activity weight of each link, in the future has not been explored yet. Moreover, we also aim to uncover the mechanisms that enable the prediction of a weighted temporal network. We achieve this by devising several strategies that help us select the most relevant links within the network, whose activity weights in the past serve as the input for the interpretable, statistical learning algorithm, LASSO Regression, to predict the activity of a given target link at time $t+1$. The focus of the strategies is to capture a relationship of activity weights between the selected and target links. These selected links range from most active links (amount of timesteps the link weight is non-zero), those with largest activity weights or most similar to the target link using several metrics. In this thesis we apply this general methodology to two bipartite networks sourced from real world data and evaluate the performance of different strategies. Through the learned LASSO coefficients and prediction accuracy, we discover that past activity weight of a link is the best predictor for it's future weights. In terms of predicting power, most is coming from the past weights of the link we want to predict and one or two neighbouring links. Most of the selected links have minimal impact on the prediction accuracy. While different strategies of link selection excel in specific conditions, their improvement over the random link selection, is relatively low. The proposed method could be further applied to predict other weighted temporal networks with different properties to understand whether and how the the performance of link selection strategies depends on properties of the network to be predicted.","Bipartite Network; Link Prediction; LASSO; Human mobility; COVID-19; Telecommunication; flow network","en","master thesis","","","","","","","","2024-12-31","","","","Computer Science","",""
"uuid:9a84b21e-c636-4a58-bdab-8f6fc76d0c40","http://resolver.tudelft.nl/uuid:9a84b21e-c636-4a58-bdab-8f6fc76d0c40","Prompting sustainable behaviour: triggering a stop and rethink process through the exposure to a combination of static and dynamic norms","Muurling, Lidewij (TU Delft Industrial Design Engineering; TU Delft Design, Organisation and Strategy)","Mugge, R. (mentor); van den Hende, E.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Overconsumption plays a big part in the current environmental crisis, making a shift towards sufficient consumption imperative. Since overconsumption is often a habit, triggering a stop and re-think process in the consumers' minds may be the way for reduction. Societal norms, proven effective for behaviour change, could disrupt consumption habits by combining a static (present norm) and dynamic (how the norm is changing) norm. This thesis explores the impact of combining sustainable and unsustainable framings of static and dynamic norms on consumer behaviour. A laboratory study exposed participants to four norm combinations before engaging in a shopping task. No significant differences emerged in the number of items selected or the time spent shopping across groups. However, a marginally significant interaction effect hinted at the potential influence of combined static and dynamic norms: participants selected the most items with two matching sustainable norms and the least with matching unsustainable norms. Notably, upon removing older participants from the data, this interaction effect disappeared and the effect of the dynamic norm became significant. Unsustainable norms triggered significantly higher negative emotions than sustainable ones, while sustainable norms elicited significantly higher positive emotions. Yet, neither significantly mediated the relationship between static and dynamic norms and item selection. These findings are relevant for marketeers and (communication) designers of companies seeking to engage in demarketing or government agencies promoting sufficient consumption. These results can lay the foundation for more extensive research into this combination of static and dynamic norms, which could be used to make stronger messages to promote both sufficient consumption and other sustainable behaviour.","overconsumption; static and dynamic norms; Sustainable Behaviour","en","master thesis","","","","","","","","","","","","Strategic Product Design","Master Thesis, strategic product design, TU Delft",""
"uuid:b9f77318-3006-48ce-a46e-7d1041d17925","http://resolver.tudelft.nl/uuid:b9f77318-3006-48ce-a46e-7d1041d17925","GPU-Accelerated Atmospheric Large Eddy Simulation: Preparing DALES for the Exascale Era","Jungbacker, Caspar (TU Delft Civil Engineering & Geosciences)","Jansson, F.R. (mentor); de Roode, S.R. (graduation committee); Costa, Pedro (graduation committee); Siebesma, A.P. (graduation committee); Delft University of Technology (degree granting institution)","2024","Large Eddy Simulation (LES) is a mathematical technique for performing simulations of turbulent flows, such as those found in the Earth’s atmosphere. Compared to traditional numerical weather and climate models, LES is more accurate in representing turbulent processes and cloud dynamics. The computational burden of LES, however, have histor- ically limited its application to relatively small domain sizes. In this work, part of the DALES atmospheric LES model was ported to Graphics Processing Units (GPUs) using the OpenACC programming model. GPUs, originally designed for accelerating computations related to 3D computer graphics, excel at parallel computations, which are abundant in LES models. The performance of the GPU port of DALES was measured on an NVIDIA RTX 3090 in a desktop workstation and an NVIDIA A100 in the Snellius supercomputer and compared to the existing CPU implementation. For the BOMEX intercomparison case, a speedup of 11.6 was achieved versus 8 CPU cores on the desktop system, while on Snellius a speedup of 3.9 was observed compared to 128 CPU cores. Furthermore, the existing MPI parallelization of DALES was adapted such that multiple GPUs can be used simultaneously. This thesis represents a step towards the enhancement of the scalability of DALES, enabling simulations on larger domains at higher resolutions. While a substantial acceleration of DALES was achieved, further efforts are needed to port more components of the model to the GPU to facilitate the simulation of increasingly realistic meteorological phenomena.","Large Eddy Simulation; Graphics Processing Units; High Performance Computing; OpenACC","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:c72bd006-8a93-4d53-acab-d63bb2eb5e5d","http://resolver.tudelft.nl/uuid:c72bd006-8a93-4d53-acab-d63bb2eb5e5d","Design and Optimization of Hyperboloid Lattice Structures for Timber Towers: A Study on Stiffness and Material Efficiency","Ačas, Dom (TU Delft Civil Engineering & Geosciences)","Ravenshorst, G.J.P. (mentor); Kavoura, Dr. Florentia (graduation committee); Schipper, H.R. (graduation committee); Oval, R. (mentor); Veenendaal, Diederik (graduation committee); Delft University of Technology (degree granting institution)","2024","The presented research aims to design and optimize a timber observation tower, with a primary focus being the influence of topological and curvature parameters on its stability and lateral stiffness in resistance to non-uniform wind load profiles.
Having recognised the environmental benefits and urgency to find other alternatives, there's a clear necessity to incorporate wood as the main construction material into the infrastructure projects, like observational towers. By conducting a study on hyperboloid towers implemented in the last 100 years, this project questions the necessity of in plane stiff platforms, flexurally stiff rings and continuous vertical members as being pivotal to the stability and lateral stiffness of the global structure when subjected to non-uniform wind loads. In addition, the study intends to investigate how the narrowness of the hyperboloid might affect the lateral stiffness of the structure. Thus, by utilizing parametric tools (Grasshopper, Karamba3D and Beaver plug-in), the study aims to design a timber tower structure comprised of fully segmented members as well as incorporation of circular (flexurally stiff) rings, aiming to address the questions raised. In terms of structural member arrangement, the study will investigate two topologies: one featuring a diagrid pattern that emulates a geometrical shape of an antiprism, and a custom pattern inspired by the post and beam approach, which resembles a regular prism shape. The study emphasizes the tower's multi-functionality and adaptability throughout its lifespan. Tower's main structural framework is a pivotal element in providing required stiffness and strength by excluding the need for in-plane reinforcement provided by arbitrarily placed platforms.
The key realisation of this research was the kinematic behaviour exhibited by the segmented, triangular tower, adversely impacting its stability characteristics. The study used a combination of analytical and graphic kinematics techniques, along with a physical mock-up model, to confirm the kinematic behavior of the tower given that even sided polygons for rings are incorporated. This revelation would have an impact on how a structure like that would perform as well the way it would be built. Further research unveils the strong influence of ring type on structural stiffness showing that segmented rings render tower structures less stiff than ones employing curved ring members, regardless of the pattern. In terms of the direct comparison between tower patterns, custom one demonstrated a more consistent and stable performance in general, particularly achieving higher stiffness levels when employing segmented rings. As regards the triangular pattern, the stiffest response against wind loads has been exhibited through the use of curved rings. In addition, the study validates that adopting a hyperboloid shape along with smaller shape factors for the global tower geometry yields more favorable lateral stiffness characteristics. Finally, the study navigates through the exploration of the most optimal connection design, illustrating how considerations related to detailing have necessitated a re-evaluation of the most optimal tower configuration, which initially was chosen to be a triangular one equipped with curved rings. A qualitative assessment of a potential joint within this specific tower variant has confirmed that designing such a connection is significantly more complex. This is due to the necessity of ensuring the continuous flow of the curved ring, emergence of a kink within the insertion of the plate and how that is needed to be addressed.
Alternatively, these considerations have motivated the design process to converge into a new hybrid design, integrating segmented rings with a curved top ring defined by the custom pattern. This choice has been made by conducting a separate parametric study of the new tower design and ensuring that the new connection design fulfills elastic slipping modulus and ultimate strength requirements. The final topology that showed higher stiffness metrics was the custom one. It's also highlighted that maintaining the top of the tower constrained leads to favorable effects on stability and stiffness, irrespective of the chosen topology. The resulting structure is optimized for mass by strategically reducing member cross-sections in accordance with connection scheming while adhering to both SLS and ULS criteria.","Timber Structures; Parametric Engineering; optimization; Hyperboloid","en","master thesis","","","","","","","","","","","","Civil Engineering | Structural Engineering","",""
"uuid:235d85e8-5c35-4cda-8bff-506aed7c511a","http://resolver.tudelft.nl/uuid:235d85e8-5c35-4cda-8bff-506aed7c511a","Becoming green together: The case of SAENZ","Broeder, Lara (TU Delft Technology, Policy and Management)","Korevaar, G. (mentor); Okur, Ö. (graduation committee); Delft University of Technology (degree granting institution)","2024","To reach the Dutch renewable energy (RE) targets of 2030, the entire Netherlands has been investing in solar energy, electric vehicles and other systems based on RE. This increase of electricity use does not come without problems and the most pressing one is that of network congestion. Due to this, businesses are no longer able to expand their electricity connection or even start their business to begin with. This has the effect that businesses cannot continue their sustainable efforts and in the worst cases it causes power to go out and stopping businesses from operating completely. A proposed solution to this problem is the introduction of a community energy system (CES). This concept and how it can be used in practice will be explored in this research in the context of an industrial park and with the support of business energy cooperative, SAENZ. They have already developed an industrial community energy system (InCES) in the form of a collective energy contract, and there is an opportunity in increasing the participation of their members. Through interviews and surveys, business owners are asked about three InCES scenarios and their more general opinion on InCES. To obtain a comprehensive view of the situation, two other stakeholders in this system are interviewed as well. These are the distribution systems operator (DSO) and the local government. The results show that business owners are willing to increase their participation in an InCES but give clear terms for doing so. They need transparent and complete information about the project and all its financial and juridical aspects. Besides, it should be easy to participate. The DSO highlighted that they support businesses organizing themselves like this and comments on how an InCES could help solve network congestion as it ensures efficient management of the energy system. The local government representative believes that they have little influence on the development of an InCES but that they do have an impact in motivating businesses to participate in an InCES. The research also shows the importance of an energy cooperative or any kind of group collaboration between businesses to organize an InCES. It is helpful in obtaining contact with stakeholders but also enhanced the group feeling between business owners and in turn their willingness to increase participation in an InCES.","Industrial Community Energy System; Network congestion; Local energy cooperative; Industrial Park; community energy system; Congestion","en","master thesis","","","","","","","","","","","","Industrial Ecology","","52.50770680309441, 4.783222440261277"
"uuid:03aea8b1-e8dd-43f4-8b67-78adcd3d4e2a","http://resolver.tudelft.nl/uuid:03aea8b1-e8dd-43f4-8b67-78adcd3d4e2a","Enhanced characterization of tow gaps in fiber steered laminates: Advanced specimen design for better representation of defects in structures","Czél, László (TU Delft Aerospace Engineering)","Peeters, D.M.J. (mentor); Castro, Saullo G.P. (mentor); Delft University of Technology (degree granting institution)","2024","The thesis aimed to characterize the effects of manufacturing-induced defects, particularly gaps in variable stiffness laminates. The primary focus centered on designing a specimen capable of accurately characterizing gap effects. A refined, element-level specimen design featuring a controlled gauge zone was developed, based on pre-defined requirements to represent common variable stiffness structures accurately. The specimens were manufactured and tested. The experimental work featured Digital Image Correlation, Dye Penetrant Testing, and Optical Microscopy. Experimental observations revealed deformation peaks induced by gaps, along with trends in void formation and ply deformation during curing processes. Furthermore, digital image correlation (DIC) analysis unveiled distinct out-of-plane tendencies associated with gap locations. Discrepancies between finite element method (FEM) results and experimental strain distributions highlighted the need for improved modeling, particularly accounting for ply waviness. The main hypothesis presumes that the effects of gaps are influencing off-axis plies through matrix failures. The hypothesis was not proven true based on insufficient proof.","Variable Stiffness Laminate; Fiber Steering; Automated Fibre Placement; Manufacturing Induced Defects; Ply Drop-off; Tow Gaps","en","master thesis","","","","","","","","2024-09-01","","","","Aerospace Engineering | Structures and Materials","",""
"uuid:c7d5de90-2eac-483a-b7c4-daf483982da5","http://resolver.tudelft.nl/uuid:c7d5de90-2eac-483a-b7c4-daf483982da5","Modelling the impact of supersonic aviation emissions on atmospheric ozone concentrations using data-driven methods","van Cranenburgh, Tom (TU Delft Aerospace Engineering)","Dedoussi, I.C. (mentor); van 't Hoff, J.A. (mentor); Fasel, U. (graduation committee); Grewe, V. (graduation committee); Lourenço Baptista, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","With renewed interest in the development of civil supersonic aircraft, their return in the future is becoming more ever more likely. The environmental impact of emissions in the stratosphere on climate and the ozone layer therefore needs to be explored. The stratospheric ozone levels determine the amount of harmful ultraviolet radiation reaching the Earth's surface and thus the level of risk to human health and ecosystems. Ozone response is complex, varying with emission altitude and latitude and we are currently reliant on computationally expensive chemistry-transport models to calculate chemical species concentration changes resulting from supersonic aviation emissions. This paper takes a novel approach to reduce the dependency on these models, creating data-driven dynamical systems that model the global spatiotemporal atmospheric ozone response for different emission scenarios. The dynamic mode decomposition (DMD) and proper orthogonal decomposition (POD) methods are applied to atmospheric ozone data obtained from the GEOS-Chem model, and the evolution of the dominant POD spatial modes are modelled using sparse identification of nonlinear dynamics algorithm (SINDy). We show that DMD models can reconstruct monthly global column ozone changes with root mean square errors less than 0.05 Dobson unit (DU) for a period of three years. Predicting the global mean column ozone changes for the years beyond the period used to construct the models, results in errors less than 0.12 DU. Independent DMD models at two different altitudes can be interpolated to produce estimates for ozone response at an intermediate altitude. These methods can serve as a basis for low dimensional surrogate models that can be used to evaluate chemical species concentrations changes as a result of supersonic aviation emissions.","atmospheric chemistry modelling; supersonic aviation; non-CO2 emissions; dimensionality reduction techniques; data-driven modelling; dynamic mode decomposition; proper orthogonal decomposition; sparse identification of nonlinear dynamics","en","master thesis","","","","","","","","2024-07-01","","","","Aerospace Engineering","",""
"uuid:35a897a9-b80a-471e-aaf5-5f9294212955","http://resolver.tudelft.nl/uuid:35a897a9-b80a-471e-aaf5-5f9294212955","A Graph-Neural-Network Approach for Reconstructing Temporal Networks","Broeders, Theo (TU Delft Electrical Engineering, Mathematics and Computer Science)","van Iersel, L.J.J. (mentor); Julien, E.A.T. (graduation committee); Delft University of Technology (degree granting institution)","2024","Reconstructing a minimum reticulation network from phylogenetic trees is used in evolutionary studies. In this thesis, we focus on finding temporal networks using cherry-picking sequences for binary trees with all taxa. Finding such a minimum reticulation temporal network is NP-hard.
We introduce an algorithm to find a minimum reticulation network with a running time of O(2^n poly(n,t)). In addition, this study explores potential enhancements to the algorithm through the utilisation of branch and bound.
Additionally, we introduce a similar algorithm to determine the existence of a temporal phylogenetic network. This algorithm is improved upon by integrating a new concept called cherry growing. This leads to a notable speed-up in performance.
Furthermore, we examine the application of Graph Neural Networks (GNN) in heuristics to find a cherry-picking sequence which can be used to construct a network. This is done by classifying leaves into good, which leads to optimal solutions, and bad leaves. To assess this, two types of data were employed: one simulating evolutionary models and the other employing a fully random approach. The best-performing GNN model has a 97.4% accuracy for evolution-based data and a 79.1% accuracy for random-based data.
The GNN models are implemented as predictors in two classes of heuristics. The first generates a cherry-picking sequence by repeatedly picking leaves. The second class of heuristics is based on a tree search heuristic. This tree-search-based heuristic outperforms the cherry-picking-based heuristic. Furthermore, the GNN heuristics outperform their random variant, even for problems substantially larger than the GNN was trained on.
We also examine the use of GNN in predicting the existence of a phylogenetic temporal network given a set of trees. The best-performing GNN found for this problem has an accuracy of 80.3%.
Biomimicry may be a solution. It is a relatively new movement, a philosophy, that looks to nature and recognises its value. It takes inspiration from biological strategies and translates them into sustainable design solutions. Respect for nature is central to this approach.
The focus of this project was to design a playful and interactive exhibit on biomimicry that could change the visitor's perspective. This was done for Museon-Omniversum, a science museum that wanted to explore such a transformative learning experience for a new exhibit in a biomimicry zone of their current exhibition One Planet NOW!
A transformative experience is a life-changing experience. They often occur after a sense of awareness that leads to a deeper understanding of one's beliefs. By exploring the subject through hands-on activities, the chance of changing one's perspective over time increases.
This project uses the double diamond method to explore these topics. Desk research, interviews, observations and exploration of museums all contributed to defining the project direction 'Solving relatable events through biomimicry'. Events refer to a relatable situation that visitors encounter (daily). This led to a more detailed design goal:
‘Design a playful and interactive exhibition suited for families with children (8 years and up) to explore biomimicry and let them understand the usefulness of biomimicry for future problem-solving for the coming ‘biomimicry zone’ at Museon-Omniversum.
This consists of four phases:
1. Make the visitor aware of what biomimicry is and can do.
2. Encourage dialogue between families to stimulate self-reflection and deeper understanding of biomimicry by presenting information invitingly.
3. Let the visitor interact with the concept of ‘biomimicry’ in a playful way by solving ‘events’ through simplified steps taken from Biomimicry Thinking.
4. Plant a seed for future problem-solving (to use biomimicry).'
Ideas were then generated through brainstorming sessions, leading to several physical prototypes. Evaluation testing of these prototypes provided insight into the experiences and effects of the designed prototypes. These insights all contributed to the final design concept of 'Superpowers of Nature'. A concept that allows the visitor to explore and reflect on biomimicry.
Visitors explore biomimicry through an interactive choosing system. They can explore specific organisms displayed on activation blocks. After placing one of the organisms, they can explore the superpowers (biological strategies) of the organism and its corresponding biomimetic innovations. The video clips guide the visitor through a simplified version of the biomimicry thinking method. During the video clips, visitors have the opportunity to reflect on the content through open-ended questions that stimulate discussion. Finally, they are shown real-life examples related to their chosen superpower.
Overall, the exhibit is successful in addressing biomimicry. However, further modifications are needed to improve the design and to test the impact in the long term (Phase 4).
Despite being perceived as a low-impact activity, research conducted by Delft University of Technology reveals that over one-third of cyclists suffer from saddle sores (Groenendijk et al., 1992). This prevalence is even higher among sport-cyclers, with complaints often focusing on discomfort around the perineum and sit-bones, potentially hindering participation in the sport (Napier & Heron, 2022).
Throughout this research, it became apparent that achieving a comfortable saddle experience hinges on two crucial factors: a saddle design selected to fit the purpose (cyclist’s anatomy, cycling posture, and personal preferences) and a proper bike fit. Despite their significance, these aspects are frequently disregarded during the saddle purchasing process. As a result, cyclists may find themselves cycling through multiple saddles before discovering the right fit or resorting to costly professional bike fitting services.
In response to these findings, this thesis proposes the development of a bicycle saddle with a variable side profile. This way, the rider can adjust the saddle to align it with the pelvic bone. Therefore creating an optimal pressure distribution, leading to less saddle sores. This has been done by introducing a hinging frontal and rear part, covered by a specially designed padding that makes sure that a smooth profile is established. Additionally, bike and saddle fitting items and a simple guide are provided to the customer and should help find a better bike fit at home.","Ergonomics; Personalized product; Comfort; Saddle; Bicycle; Additive Manufacturing","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:acf84599-a547-4361-8c55-117b3add4b68","http://resolver.tudelft.nl/uuid:acf84599-a547-4361-8c55-117b3add4b68","Optimisation of femoral osteotomies around the knee using the finite element method","van der Weijde, Joël (TU Delft Mechanical Engineering)","Magré, Joëll (mentor); Weinans, Harrie (mentor); Tümer, N. (graduation committee); Nguyen, Chien (graduation committee); Delft University of Technology (degree granting institution)","2024","Introduction
Osteoarthritis (OA) is a prevalent joint disease affecting 7% of the global population in 2020. Lower limb malalignment emerges as a significant contributor to OA, presenting as varus or valgus misalignment. This deviation induces unicompartmental pathology, leading to the wear and tear of the protective cartilage. Surgical interventions, including osteotomies, are essential in managing unicompartmental knee OA. During osteotomies, hinge fractures are a common complication. This paper focuses on optimizing open wedge osteotomies, specifically exploring complications in medial open wedge distal femoral osteotomy (DFO) using finite element models. And investigates the viability of the medial open wedge DFO compared to the lateral open wedge DFO.
Method
The research employed a systematic approach to investigate ways to avoid hinge fractures in Distal Femoral Osteotomy (DFO). Finite Element Modelling (FEM) served as the cornerstone of our methodology, providing a numerical solution. The process involved the creation of finite element models from CT scans through the subdivision of femoral geometry. The automated generation of these models was facilitated by a combination of 3-matic, Mimics, and Abaqus. Using Python scripting in these different programs, a workflow for model creation and parameter variation was created. The lateral open wedge DFO model, serving as the baseline, underwent systematic alterations to explorethe impact of hinge size, osteotomy gap angle, and other variables. The creation of finite element models involved several key steps, including geometry creation, mesh generation, addition of material properties, and the application of boundary and loading conditions. Material properties were assigned based on a simplified isotropic model derived from Hounsfield units. Extra attention was given to automate the process of model generation to ensure efficiency and reproducibility.
Results
Six distinct models were created with a comprehensive analysis of their attributes and shortcomings. The study finds that the medial open wedge DFO does not induce hinge tension. Comparative analyses in both opening and loading stages reveal nuanced stress and strain differences with the lateral open wedge DFO. No clear conclusion can be given as to the viability of the medial open wedge DFO compared to the lateral open wedge DFO. In-depth exploration indicates that smaller hinges are favourable for osteotomy gap opening, while larger hinges (10mm and above) contribute to stability during loading. Minimal impact on stress concentration is observed for osteotomy gap angle variations. The study explores the effectiveness of drill holes in stress relief, highlighting precision challenges.
Discussion
Acknowledging inherent limitations such as partial volume effects and assumptions about material properties. The study suggests promising avenues for future research. Recommendations for future research include in vivo experiments, exploration of XFEM and fracture mechanics, and further refinement of modelling techniques. This study provides nuanced insights into hinge fractures during open wedge DFO, guiding future research and bridging the gap between finite element modelling and
clinical realities.","","en","master thesis","","","","","","","","","","","","Biomedical Engineering","",""
"uuid:27c99966-dbf8-4550-948c-44e10b1b8518","http://resolver.tudelft.nl/uuid:27c99966-dbf8-4550-948c-44e10b1b8518","Redesign of the Car Distribution Process: a Dutch case study: A Holistic Approach in a Capacitated Vehicle Routing Problem to Reduce Direct CO2 Emissions in a Truck-Based Car Distribution Process","Koopal, Wisse (TU Delft Civil Engineering & Geosciences)","Vleugel, J (mentor); Schulte, F. (graduation committee); Negenborn, R.R. (graduation committee); Delft University of Technology (degree granting institution)","2024","Purpose - With the short term need to reduce direct CO2 emissions of trucks in distribution processes, this paper aims to provide an easy to implement solution approach for distribution processes of new cars from holistic perspective. Scarce emphasizes is provided on short-term alternatives in truck-based distribution processes and approaches lacks applicable for large scale problems including split delivery function.
Design/methodology/approach - The distribution process and model methods are analyzed using a literature study and interviews with experts, resulting in the development of a solution approach. Combined with an extensive field research, a solution approach enables the performance evaluation of the current state, and the policy implications. Future designs are used to validate the solution approach by calculating performance differences in multiple relevant evaluation domains.
Findings - The analysis of the current state has identified critical bottlenecks, leading to the development of two promising policies. The application of a new and validated prioritization strategy and permitting more stops per truck has successfully yielded a significant reduction in CO2 emissions. The performance of the solution approach demonstrates high precision on a small scale and yields results comparable to actual practices on a larger scale, suggesting the approach's effectiveness and potential for future application.
Research limitations/implications - This research provides a new solution approach for evaluating direct CO2 emissions of model different designs of distribution processes. Despite its narrow scope, the transportation sector has a significant environmental footprint, and offers the potential for substantial reductions in emissions. From modeling perspective, further research is suggested in integrating split delivery function without using dummy variables.
Originality/value - This paper contributes by identifying critical gaps in the understanding and implementation of system-wide efficient car distribution processes from distribution hubs to car dealers. It not only addresses potential improvements, but also proved efficiency gains of the system with a new solution approach, using a new combination of a state-of-the-art meta-heuristic and a proven split delivery method applicable for large-scale problems.","Environmental impacts; Capcitated Vehicle Routing Problem; Split-delivery; Trucks; Car distribution","en","master thesis","","","","","","","","","","","","Transport, Infrastructure and Logistics","",""
"uuid:f22e9a89-5cee-4d7d-be1d-d818de2b7d73","http://resolver.tudelft.nl/uuid:f22e9a89-5cee-4d7d-be1d-d818de2b7d73","Promoting well-being among adolescents: Exploring the added value of a systemic design approach","Vos, Kirsten (TU Delft Industrial Design Engineering)","van der Bijl-Brouwer, M. (mentor); Huisman, G. (graduation committee); van der Wal, Koen (graduation committee); Delft University of Technology (degree granting institution)","2024","75% of all mental health issues arise between the ages of 14 and 25 (Kessler et al., 2005). Suicide is the number one cause of death among young people (Centraal Bureau voor de Statistiek, 2023), one in three adolescents experiences performance pressure (Kleinjan et al., 2020), one in seven adolescents has depressive symptoms (Kleinjan et al., 2020) and life satisfaction has decreased significantly over the past 20 years (Kleinjan et al., 2020). All of these statistics show one thing: a lot of adolescents have poor mental health and they seek more professional help because of it. However, youth care cannot handle this increased demand. This combination leads to problems and therefore a new approach is needed. In my project, I used a systemic design approach and focused on promoting well-being instead of only fixing mental health issues. Accordingly, the main research question in my project is:
“How can the systemic design approach contribute to improving well-being among adolescents (ages 16-18)?”
I used a systemic design approach to look at the larger system around adolescents to find new opportunities for possible interventions. I interviewed a lot of different stakeholders and explored their perspectives and their interactions with other stakeholders. I processed these insights into a giga-map, which helped me formulate three themes and eventually choose one theme: ‘Who is responsible’. This theme deals with a social norm where parents are held responsible for the upbringing and well-being of their children, whereas adolescents at this age distance themselves from their parents and need other adult support figures (McElhaney et al., 2009). In addition, the support adolescents receive in this system depends on individual motivation: some people recognize their role, others do not. From this theme and all the insights from the stakeholder sessions, I formulated a future vision which is represented by this African proverb:
“It takes a village to raise a child”
The shift needed to achieve this future is from scattered islands to a connected proverbial village. To achieve this, I chose teachers' mental models as a leverage point (Meadows, 1999). By showing teachers the value of their role, the value of promoting well-being and the value of connections, I hope they will also change their behaviour. From that goal, I designed my intervention OmDraaien, where three teachers are each given a role: a teacher, a parent and an adolescent. They play an interactive game in which they play a scenario and interact with ropes (connection pieces) that represent their relationships. After this interactive game, the participants reflect on the game they just played and relate it to their own work.
To shortly answer my research question, a systemic design approach has helped me to look at the broader system around adolescents and has therefore helped to create not only stakeholder value, but also potential systemic value. In addition, a systemic design approach has allowed me to discover an underlying problem: stakeholders focus just on symptomatic solutions rather than also on fundamental solutions.","Well-being; Adolescents; Systemic design","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:3f5c3978-4f87-4ade-b3e5-cd1cf921ed3f","http://resolver.tudelft.nl/uuid:3f5c3978-4f87-4ade-b3e5-cd1cf921ed3f","The Care Companion App: Managing parental stress in pediatric outpatient trajectories","Eshuis, Pauline (TU Delft Industrial Design Engineering)","Gielen, M.A. (mentor); Vegt, N.J.H. (graduation committee); Poot, Charlotte (graduation committee); Delft University of Technology (degree granting institution)","2024","Visits to the pediatric outpatient clinic are often accompanied by stress and anxiety, not only in the child but also within the parents. Within current trends in healthcare, parents are becoming more and more involved in the treatment of their child. The Hospital Hero Foundation, that already developed an app to reduce hospital related fear and anxiety in children, therefore showed interest in the question of how to support parents with this more engaged role.
IMPORTANCE OF PARENTAL SUPPORT
Literature showed that outside of the hospital context, when healthcare professionals are not present, children depend on their parents to provide the needed support. Also, during the outpatient visit parents play a very important role: children tend to look at their parents in stressful situations to determine an appropriate response. For parents to be able to execute existing strategies to reduce stress in their child, they need to possess the necessary knowledge and skills. More importantly, parents need to be able to manage their own stress, to not transmit this stress onto their child.
CHALLENGS OF PARENTS
Observations in pediatric outpatient clinics and interviews with parents and healthcare professionals confirmed and added to the previously described findings. According to this research, parents would ideally be honest, calm and radiate trust when supporting their child. The outpatient trajectory of their child, though, comes with an increase in (perceived) responsibilities of the parent possibly causing parents to be stressed. In this context, parents are generally fully focused on their child, making them unaware of their own increasing stress levels. Challenges parents experience in the context of the pediatric outpatient trajectory of their child are (1) Engaging with their social environment, (2) Gaining information, (3) Taking care of oneself, (4) Seeing their child in pain, (5) Supporting their child and (6) Working together with healthcare professionals. Support mechanisms to help parents deal with these challenges are limited and often not received by parents.
MANAGING PARENTAL STRESS
To manage parental stress, an intervention that supports parents of pediatric patients (aged 4-10 years old) with their challenges in the context of outpatient visits was designed. The focus thereby was to help parents to take care of themselves. Several brainstorming activities were executed in the ideation phase. The created bulk of ideas converged into 3 concepts, which were compared based on insights gained in this project and interviews with stakeholders. The most favorable concept was further developed into the Final Concept: the Care Companion app.
THE CARE COMPANION APP
The Care Companion app is a standalone app offered to parents by the Hospital Hero Foundation. It offers parents both affirmations as well as general tips for situations and challenges they can possibly encounter in the outpatient trajectory of their child. Each tip consists of advice from an expert and an experience from another parent. The provided tips can be read, saved and shared. A short evaluation with parents and an expert showed promising results for the concept of the Care Companion app.","Supporting Parents; Pediatric Outpatient Trajectory; User-Centered App Design; E-Health; Hospital Hero","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:943789b9-f5b9-4a3c-8703-2ff74b3df140","http://resolver.tudelft.nl/uuid:943789b9-f5b9-4a3c-8703-2ff74b3df140","Employing Sensitivity Analysis for Evaluation of Vibration Effects on Multi-Mirror Optomechanical Systems","Postma, Thies (TU Delft Mechanical Engineering)","Bhattacharya, N. (mentor); van Kempen, Floris (graduation committee); van den Boom, Sanne (graduation committee); Delft University of Technology (degree granting institution)","2024","This study presents a novel approach for evaluating the effects of dynamic disturbances on optical performance using sensitivity analysis. The computation of optical performance for perturbed optical systems is too costly with state-of-the-art analysis software when applied in the use case for the optimization of the optomechanical interface, and therefore using a simplified model, based on ray transfer matrices, describing the most critical phenomena provides a solution. The proposed analytical framework employs a Taylor expansion for the merit function, incorporating both the Jacobian and Hessian matrices, to reduce computation time in transient analysis. The effect of small perturbations on the merit function is found to be accurately described by the approximation when solely the Jacobian is included, for larger displacement fields the approximation deviates significantly without the inclusion of the Hessian. Next to this, the definition of a grating matrix is appended to the framework to facilitate the analysis of a larger set of systems. For transient analysis, the proposed framework exhibits a remarkable improvement in computation time, with minimal degradation in accuracy for paraxial systems. All findings hold relevance for the effect of rigid body displacements in coupled mechanical-optical analyses and further optimization of this coupling under disturbed conditions.","Optomechatronics; Sensitivity analysis; Vibrations","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Optomechatronics","",""
"uuid:a07d6f73-16b1-45fc-af1a-096024410513","http://resolver.tudelft.nl/uuid:a07d6f73-16b1-45fc-af1a-096024410513","Moving measurements: Measurements of the turbulent/non-turbulent interface of a round jet in a co-moving frame of reference","Been, Coen (TU Delft Mechanical Engineering)","van Dalen, L.E. (mentor); Westerweel, J. (mentor); van de Water, W. (graduation committee); Rahimi Khojasteh, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","At the turbulent/non-turbulent interface (TNTI) of a jet flow, momentum is transferred from the turbulent jet fluid to the fluid at rest. This transfer is governed by two mechanisms. One of them is related to the large scales of the flow and the other relates to the small scales of the flow. Which of the two is dominant is still a point of discussion. To analyse the TNTI the instantaneous information of the flow and the location of the interface is of great importance. However, the interface simultaneously develops and travels downstream from the nozzle. With stationary measurement techniques this limits the number of frames the interface can be seen developing as it travels in and out of the FOV. In this thesis the TNTI is measured using a camera system that moves along with the TNTI to get high resolution instantaneous measurements of the same part of the evolving interface. The measurement techniques that are used for this experiment are Particle Image Velocimetry (PIV) and Laser Induced Fluorescence (LIF). The cameras for these measurements are mounted to a motorised frame to keep the same part of the interface in view of the cameras as it develops.
Three Reynolds numbers are measured with this setup and the cameras move approximately 50Dn at a velocity close to the velocity of the interface along a diagonal path to follow the evolution of the TNTI.
One measurement with a Reynolds number of approximately 1.2 × 104 has been processed to show the quality of the results that can be obtained from such a measurement. The velocities are computed by an in-house interrogation analysis program in MATLAB to overcome the wide range of particle displacement found in this experiment, due to the presence of both the centreline and the TNTI of the jet. The TNTI is detected using the LIF data and a threshold detection method from literature that determines a threshold value. The results from the PIV and LIF processing is combined to compute the average conditional vorticity over the interface.
The results show that the PIV analysis is able to compute the velocities of almost the entire jet. Only showing a lot of spurious vectors close to the nozzle in the core of the jet. The LIF edge detection algorithm, on the other hand, does not perform as expected. In multiple instances, an internal interface is detected instead of the TNTI. The TNTI is also determined by identifying a threshold value through a visual inspection of the LIF images. This manually determined TNTI is used as a point of comparison for the average conditional vorticity profiles. The average conditional vorticity profiles support the conclusion that an interface internal to the jet is detected when comparing the interface from the algorithm to the interface determined manually.
Although not quantified in this thesis, there are moving measurements that show the same section of the TNTI evolving for many frames. This gives the co-moving measurements a clear advantage in measurement time compared to stationary measurements when trying to measure the moving TNTI. Refinements to the experimental setup, the behaviour of these internal interfaces and the detection of the TNTI can be of interest for future research.","Turbulent/non-turbulent interface; Jet; PIV (particle image velocimetry); LIF","en","master thesis","","","","","","https://www.youtube.com/watch?v=O-WBgnZn_l0 A video of the raw LIF images from the co-moving measurements","","","","","","Mechanical Engineering","",""
"uuid:a39340b9-06d2-4462-812e-f79450890bdd","http://resolver.tudelft.nl/uuid:a39340b9-06d2-4462-812e-f79450890bdd","Integration of alumina ultrafiltration membrane and palladium-catalyzed peroxymonosulfate for removal of organic micropollutants","Tian, He (TU Delft Civil Engineering & Geosciences)","Heijman, Sebastiaan (mentor); Rietveld, L.C. (graduation committee); Spanjers, H. (graduation committee); Tanis, M.B. (graduation committee); Zhang, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","Organic micropollutants (OMPs) originate from organic chemicals such as drugs and pesticides that are widely used in human activities. OMPs are difficult to remove by conventional water treatment techniques, and hence continue to accumulate in natural water bodies. More effective methods need to be investigated for the removal of OMPs in drinking water treatment because of their toxicity and carcinogenicity, which may pose potential risks to human health. Previous studies have suggested that the use of activated peroxymonosulfate (PMS) catalyzed by Palladium (Pd) immobilized in ultrafiltration (UF) membranes can effectively degrade 1,4-dioxane and p-nitrophenol, while its removal efficiency for other OMPs, limiting factors and reaction mechanism still require for more research. In this study, PMS-Pd/UF system was established by coating Pd on the surface and 20 nm pores of the ultrafiltration membrane. The effectiveness of PMS-Pd/UF in the removal of OMPs from ultrapure water under various flux, pH, PMS dosages and ions presence was examined, as well as the performance in other water matrices including simulated brackish water, simulated brine water and river water. The results showed that PMS-Pd/UF achieved more than 95% of OMPs removal in 1 and 12-hour filtration tests at a flux of 30 LMH, while removal efficiency decreased with the increased flux due to the reduced contact time. The pH tests indicated that the system was more efficient under a neutral pH environment. The presence of 1 mM of various ions (Cl−, HCO3−, SO42−, and ClO−) had limited effects on the degradation of OMPs. However, the removal of OMPs was inhibited when OMPs coexisted with NOM in river water and, in combination with high salt concentrations simulated brine water (e.g., with 250mM of total anions). From specific scavenger dosing experiments, it was concluded that SO4•–, •OH, and O2•– were the main reactive species induced from Pd/UF-activated PMS for the removal of OMPs.","water treatment; ultrafiltration (UF); Advanced oxidation; peroxymonosulfate","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:be29707d-2e2c-44c1-a758-c0fdfded915a","http://resolver.tudelft.nl/uuid:be29707d-2e2c-44c1-a758-c0fdfded915a","4D Printing: Post-processing for the masses","Dijkstra, Bas (TU Delft Industrial Design Engineering)","Doubrovski, E.L. (graduation committee); Ozdemir, Mehmet (mentor); Delft University of Technology (degree granting institution)","2024","class=""MsoNormal"">This research investigates the challenges a user faces in the activation step in shape-changing products. First, previous research on the topic of 4DP is reviewed and important factors are described. Namely, activation temperature, print temperature, print speed, and layer height have a signifi cant impact on the shrinkage of SMPs, during the activation step in 4DP. These shrinkages can be applied to an object through the use of varying strategies. These strategies show there are two ways of applying SMPs to a design, either calculate the shrinkage or create limits with the use of geometry-based end stops. Lastly, a further review is conducted into the type of products made with 4DP. These products turn out to be made out of three categories; fl at-packed, custom fi tment, and energy-absorbing structures. The second chapter, Material Tinkering & Exploration, delves into the material characteristics of LW-PLA, showcasing its utility for shapechanging. LW-PLA can be used both as a passive and active element, reducing environmental impact by enabling or disabling shape memory through micro-scale structural changes. This material is then used to fi nd a correlation in curvature and ratio of active versus passive elements within a design. Furthermore, the material is used to fi nd the best type of heat source, trying to create the most consistent outcomes. The oven without convection is then chosen as it creates the most consistent outcomes by limiting user interaction and making use of slower response times. The following chapter brainstorms ideas that can make use of shape change. Through the use of criteria and Edison profi les a direction is chosen. This is the direction of the temples of glasses. Shape change can add to this product as the temples vary in length to fi t different users. This chapter also creates two prototypes to be tested, differing in the type of measurement method. Lastly, the design is evaluated through the use of two user studies. In the fi rst study, the focus is laid on the type of measuring method. The external measurement method comes out as the most promising as it creates the most consistent outcome with the users. The second test tries to minimize the error between the targetted length of the temple and the actual length after the activation process has ended. The result is an addition of two test samples that educate the user. Through the education of the user, a consistent result with minimal error can be achieved. The activation step also requires a homogeneous method of heating the temple, small deviations in this heating lead to unwanted curvature. This is combatted by creating a tray, that is delivered together with the temple.","4D Printing; Shape Memory Polymer; Shape Memory Activation","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:d9be7937-9b31-40c3-b369-2354bac50bee","http://resolver.tudelft.nl/uuid:d9be7937-9b31-40c3-b369-2354bac50bee","Analytical modelling of air-gap magnetic field of surface mounted permanent magnet motors for drones","Jones, Joshua (TU Delft Electrical Engineering, Mathematics and Computer Science)","Dong, J. (graduation committee); Bauer, P. (mentor); Ghaffarian Niasar, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Drones -- small (or not so small) remotely controlled flying devices -- are seeing rapidly increasing use in many fields of application and human activities ranging from recreation, competitive sports, last-mile logistics, espionage, exploration, to media production, and even warfare. The abundance of these devices brings with it the risk of them becoming an audible nuisance due to the high pitched noise produced by their surface-mount (SM) PMSMs.
The acoustic noise produced in these motors is the product of multiple factors, but chief among them is the vibration of the motor's external shell, which is the stator for internal rotor type motors and the rotor for external rotor type. This shell vibrates in various oscillation modes as a result of the magnetic forces acting on it, which are an inevitable result of the motor's internal magnetic field and the armature currents that produce them.
This motivates research effort into reducing this noise through modulation or control strategies employed by the inverter powering the motor. In order to develop a control model, first the motor itself must be understood. In this thesis, the electromagnetic aspect of surface-mount-PMSMs will be developed, i.e. an analytical model will be established of the air gap magnetic field in SM-PMSMs.
First, the armature reaction field for arbitrary winding types will be derived, followed by a detailed derivation of equations typically used to model the rotor magnets in SM-PMSMs. A derivation of the effect of stator slotting on the air gap magnetc field will be provided, and concluded with a combination of the three previously mentioned aspects, and the dimension of time will be incorporated in the model.
Accompanying this thesis will be a set of MATLAB code that will be made publicly available for research and instruction in academia.","SM-PMSM; surface mount; air gap; analytical; permanent magnet; slotting; armature","en","master thesis","","","","","","","","","","","","Electrical Engineering | Electrical Power Engineering","",""
"uuid:c9af6a63-a1e2-4a98-bfe3-76886a0d6e23","http://resolver.tudelft.nl/uuid:c9af6a63-a1e2-4a98-bfe3-76886a0d6e23","A Lamb wave-based liquid sensor for biomedical applications","Gahar, Widesh (TU Delft Electrical Engineering, Mathematics and Computer Science)","French, P.J. (mentor); Manzaneque Garcia, T. (graduation committee); Korkmaz, E. (graduation committee); Sisman, A.S. (graduation committee); Delft University of Technology (degree granting institution)","2024","This study presents an AlN-based Lamb wave (A0 mode) liquid sensing device designed for biomedical applications. The Lamb wave device features a 1.5 μm composite membrane consisting of a 500 nm LPCVD SiN and a 1 μm of a c-axis oriented AlN film. Additionally, an innovative 45° rotated IDT design was explored to minimize edge reflections towards the output IDT. Liquid testing experiments, involving IPA, DI water, and D-PBS, were conducted to see if the devices were able to differentiate between these liquids. Results demonstrate that the fabricated Lamb wave devices exhibit sensitivity to mass loading and can distinguish between liquids based on phase, frequency, and gain characteristics. Devices with the rotated IDT design have shown a significant increase in resonance by 15 dB, as well as enhanced sensitivity compared to those with the normal design. Furthermore, devices with the rotated design demonstrated a higher Q factor of 680, indicating superior performance over the normal design (Q factor of 450). These findings suggest that a Lamb wave device with the 45° rotated IDT design holds considerable potential for applications that demand accurate liquid characterization and detection.","","en","master thesis","","","","","","","","","","","","Electrical Engineering","",""
"uuid:2053ff02-2056-4307-8216-d78a29433bf7","http://resolver.tudelft.nl/uuid:2053ff02-2056-4307-8216-d78a29433bf7","A guide to ERP strategy selection: A design study for a decision support tool","Seepers, Nikki (TU Delft Technology, Policy and Management)","Ludema, M.W. (mentor); Janssen, M.F.W.H.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis goes into the challenging process of selecting Enterprise Resource Planning (ERP) strategies, highlighting the complexities involved in deciding between different approaches. The study uses a qualitative research methodology, combining literature and interviews, to gain a better understanding of ERP strategy selection. The study sheds light on the intricate dynamics of several ERP strategies, such as the Two-Tier strategy and Best of Breed solutions, and provides insights into their benefits, downsides, and implementation implications.
The study creates a decision tool using an iterative approach driven by the double diamond technique with the goal of offering a systematic framework for selecting ERP strategies. This tool incorporates essential criteria determined through a literature research and interviews, including functionality, organisational complexity, IT expertise, and business alignment. The decision tool is intended to help organisations navigate the intricacies of ERP strategy selection, allowing them to make educated decisions that are aligned with their strategic goals and operational requirements.
The study's theoretical implications add to the existing body of knowledge by clarifying the nuances of the Two-Tier ERP strategy, highlighting the complexities of ERP strategy selection, identifying key criteria and constraints, and emphasising the importance of IT-business alignment in decision-making.","ERP; Enterprise Resource Planning; Strategy; Decision making; Two-Tier ERP strategy","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:41c1c8f5-c721-4b55-b77a-745b0a4b95df","http://resolver.tudelft.nl/uuid:41c1c8f5-c721-4b55-b77a-745b0a4b95df","Optimization of Acoustic Metasurfaces with Hybrid Structures for attenuation of broadband low frequency sound: An exploratory research on hybrid metamaterials to analyze/uncover possible practical applications/benefits for sound attenuation","Martinez Fornos, Carlos (TU Delft Mechanical, Maritime and Materials Engineering)","Aragon, A.M. (mentor); Sluiter, M.H.F. (graduation committee); Delft University of Technology (degree granting institution)","2024","We perform a study on acoustic metasurfaces, aiming to achieve simultaneously low resonance frequencies (below 400 Hz), high attenuation bandwidth (greater than 200 Hz), and high attenuation coefficient magnitudes (above 0.8), while maintaining a surface-like structure.
We propose the implementation of geometrical optimization through genetic algorithms, as well as the incorporation of a chamber to induce resonator coupling in a supercell hexagonal Helmholtz resonator metasurface, to achieve the stated objectives simultaneously.
Results show that genetic algorithms can effectively increase the attenuation bandwidth while maintaining a moderate attenuation coefficient magnitude. Incorporating a chamber induces resonator coupling, causing frequency locking and pulling phenomena. A narrow chamber can effectively lower the resonance frequencies and enhance the attenuation coefficients at those frequencies, while maintaining a surface-like structure. However, incorporating a chamber may lead to a reduction in bandwidth. By combining the genetic algorithm optimization with chamber integration, we observe a significant reduction in bandwidth narrowness, while the benefits of frequency locking and pulling are maintained.
In conclusion, genetic algorithms have the potential to achieve wide attenuation bandwidths, while chamber incorporation holds promise for attaining low resonance frequencies with high attenuation coefficients. Using both methods simultaneously may enable the achievement of all objectives.","metamaterials; acoustics; optimization","en","master thesis","","","","","","","","","","","","Materials Science and Engineering","",""
"uuid:b0bc2433-f51c-4153-add7-84791df1b02f","http://resolver.tudelft.nl/uuid:b0bc2433-f51c-4153-add7-84791df1b02f","Enhancing Semiconductor Technology Development by Co-Development and Supply Chain Integration","Var, Sezer (TU Delft Mechanical Engineering; TU Delft Marine and Transport Technology)","Napoleone, A. (mentor); Atasoy, B. (graduation committee); Zwaginga, J.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Semiconductor product development becomes increasingly challenging due to diminishing product life cycles, miniaturization, introduction of new physical principles, and new manufacturing processes. These problems are compounded in the absence of standardized development processes for the most complex semiconductor products like MEMS technologies, because the manufacturing of these products is often outsourced. Suppliers play a pivoting role in the realization of the product, from product design until process design and ramp-up. The supplier selection problem in this industry denotes the challenges in finding the right supplier while meeting all the technical, process and business requirements. The contribution of this research is in presenting how to develop a generic methodology for data-driven co-development. Thereby, this work presents a novel product development framework that leverages co-development and supply chain integration through data-driven decision-making. Co-development is reached through standardized methods for generating the required engineering output for supplier selection. Supply chain integration is introduced in the early stages of product development. This synthesizes with the outsourced manufacturing processes. Clustering algorithms are used to effectively shortlist suppliers based on their competences, and provide insights into supplier profiles and gaps. The latter is used to draw strategies for developing unattainable technologies. Using the framework, the required engineering output for supplier selection was generated in 77% less time while reducing information asymmetries between actors in the product development process. Furthermore, the framework made it possible to quantify decisions, allowed for supplier profile recognition and gap identification through its hybrid automated approach, and supplier shortlisting in 95% less time. This efficiency does not only showcase the immediate benefits of the proposed methodology, but also lays the foundation for future research towards a fully automated approach in semiconductor product development. The developed framework includes information flows between actors and steps in the product development process, their interfaces and demonstrates its added value and potential for a fully automated yet efficient future approach in semiconductor product development.","Semiconductor industry; product development; co-development; modularity; supplier selection problem; machine learning; clustering; decision-making","en","master thesis","","","","","","","","","","","","Marine Technology | Transport Engineering and Logistics","",""
"uuid:7ffca2d3-bd42-4585-ac9f-3e25fdaa2b49","http://resolver.tudelft.nl/uuid:7ffca2d3-bd42-4585-ac9f-3e25fdaa2b49","A Numerical Study on Compressible Flows over Thick Airfoils for Tilted Wind Turbines","Hemelaar, Senne (TU Delft Aerospace Engineering)","Modesti, D. (mentor); De Tavernier, D. (mentor); Delft University of Technology (degree granting institution)","2024","While the assumption of incompressible flow has been the prevailing standard for numerical simulations of wind turbine aerodynamics, the limit of this assumption is approached as the industry progresses towards increasingly higher operational tip speeds. This thesis explores the implications of compressibility and transonic flow phenomena, particularly in relation to a new rotor design that integrates the concept of rotor tilt.
The study is split into two phases. The first phase involves two-dimensional Computational Fluid Dynamics (CFD) simulations, employing an Unsteady Reynolds Averaged Navier-Stokes (URANS) framework, specifically for the thick NACA 63(4)-421 airfoil. Attention is directed at the effects of high subsonic and transonic Mach numbers, and the complex flow phenomena emerging from shock wave-boundary layer interactions (SBLI). The second phase extends the findings from the first phase by simulating a 3MW concept rotor, utilizing a lifting line method. Here, particular emphasis lies on runaway conditions; the operating point of an unloaded rotor where rotational velocity maximizes. Since airfoil drag significantly increases through the onset of “shock-stall”, it might provide a passive mechanism for overspeed protection.
The URANS study provides the first exploration of transonic buffet for a thick non-symmetrical airfoil; the phenomenon characterized by periodic shock movement, leading to large-scale load oscillations. The findings indicate that these fluctuations are significant and could pose a threat to the structural integrity of a full-scale rotor. Additionally, regarding the subcritical compressible regime, the study found that the von Karman-Tsien correction is the most appropriate method for the prediction of airfoil loads prior to reaching the critical boundary.
In the second phase, the rotor is simulated using the averaged values of the compressible aerodynamic coefficients, obtained in the first phase. Two flow scenarios are considered: Storm conditions typical for the North Sea, and subsequently, higher wind speeds often encountered during tropical typhoons in the Western Pacific. The results show that for the first scenario, shock-stall does not prevent the rotor from overspeeding. Instead, using rotor tilt is suggested as a more effective strategy. For the second scenario, a distinctive maximum rotational velocity has been found for an incoming wind speed of $57.5$ m/s, leading to the conclusion that shock-stall could effectively prevent the rotor from overspeeding.
Since the averaged values of the aerodynamic coefficients are used to assess the adequateness of shock-stall as an overspeed protection mechanism, the load fluctuations attributed to transonic buffet are initially neglected. A subsequent preliminary assessment of these fluctuations revealed that operating in the high transonic regime potentially poses severe risks regarding rotor safety.","Compressibility; Compressible Flow; Computational Fluid Dynamics (CFD); URANS; Lifting Line; shock--boundary-layer interactions; shock-induced separation","en","master thesis","","","","","","","","2026-03-26","","","","Aerospace Engineering","","51.989784, 4.374796"
"uuid:5893cf34-190f-4b48-9f2b-d4e463f47930","http://resolver.tudelft.nl/uuid:5893cf34-190f-4b48-9f2b-d4e463f47930","Integrated infection and crowd behavior model for infection risk assessment onboard large passenger vessels: Investigating the effect of ship layout design, operational and behavioral measures on contagious disease spread","de Haan, Naomi (TU Delft Mechanical Engineering)","Kana, A.A. (mentor); Atasoy, B. (graduation committee); Oikonomou, Z.P. (graduation committee); Delft University of Technology (degree granting institution)","2024","The development of the global COVID-19 pandemic from 2020 onward has had significant impact on the world and specifically the maritime industry. Striking examples were COVID-19 outbreaks onboard the Diamond Princess cruise vessel and the U.S.S. Theodore Roosevelt aircraft carrier at the start of the pandemic. Contagious disease management onboard large passenger ships remains a complex issue, amplified by the international character of the industry, confined environment and shared facilities. This report therefore presents an investigation into the effect of ship layout design, operational and behavioral measures on COVID-19 airborne infection risk onboard large passenger vessels. The novelty of this research lies with the integrated infection and crowd behavior model used to calculate agent-specific infection risk, incorporating guest and crew circulation through a passenger ship layout.","Contagious disease; Passenger vessel; Layout design; COVID-19; Infection risk","en","master thesis","","","","","","","","","","","","Marine Technology | Ship Design","",""
"uuid:a11ad2df-5f5e-4bb4-a335-596e8d35817f","http://resolver.tudelft.nl/uuid:a11ad2df-5f5e-4bb4-a335-596e8d35817f","An Evaluation of the Merging Interaction between Humans and Interaction-Aware Vehicles","Scarí, Federico (TU Delft Mechanical Engineering)","Siebinga, O. (mentor); Zgonnikov, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","As autonomous vehicle (AV) technology progresses, the necessity for a comprehensive understanding of interactions between AVs and human-driven vehicles (HVs) becomes paramount, particularly in critical manoeuvres such as merging. Mastering merging interactions is essential for enhancing road safety. Existing research in this field focuses on how the AV performs the merging manoeuvre but often fails to assess how they influence these interactions. By drawing inspiration from Human-Robot Interaction and Human Aware Navigation, this study aims to bridge this gap by examining how these interactions influence driver workload, measured through fixations duration, perceived safety and drivers’ subjective perception during merging scenarios. We employed a Virtual Reality environment to simulate realistic driving conditions and measure driver responses. We conducted an experiment where participants engaged in merging manoeuvres with each other and, subsequently and without being informed, with the AV described in “Planning for cars that coordinate with people” [1]. This approach allowed for an unbiased assessment of natural driver reactions to AV behaviours. Our findings reveal significant increases in driver workload and decreases in perceived safety during HV-AV interactions, compared to HV-HV interactions. These results suggest that current AV algorithms may not fully account for the complexity of human-AV interactions, highlighting a need for interaction evaluation in the AV development. Participants’ subjective feedback indicates a recognition of and negative reaction to AV driving behaviours, emphasizing the importance of designing AVs that are both efficient and intuitive for human drivers. The study’s implications suggest improving AV controllers’ evaluations by including their interactions with human drivers. By integrating interaction evaluation, AV technologies can achieve smoother and more successful integration into existing road systems, enhancing predictability and driver acceptance. This study marks a step towards understanding the interactions between AVs and HVs, offering insights that could steer future research and development in autonomous driving technologies.
The research is mainly motivated by the limitations of conventional charging poles, such as their scarcity, lengthy charging times, unregulated demand, and urban space conflicts as EV usage grows. Future EV statistics and charging station projections are presented underscoring how these challenges can be amplified shortly. As an alternative solution, mobile systems are introduced highlighting products, prototypes, and studies in the market and literature. Through stakeholder analysis, these systems are shown to benefit investors, consumers, and the public, supporting the grid, facilitating convenient charging.
The thesis incorporates a charging demand estimation algorithm to simulate the charging tasks on a typical day. This demand estimation is represented as private, public, and workspace charging load, sampled by considering the probability of energy demand and connection times. Next, the study integrates an iterative optimization process to simulate how effectively this demand can be addressed by a robot-like mobile charging system.
The system is simulated with different price scenarios, grid capacity values of 50 and 100 kW, varying the number of units between 3 and 5, and battery sizes between 70 and 400 kWh. As a result, it is demonstrated that mobile charging systems can effectively reduce peak demand by decoupling charging load from the grid while offering more convenient charging experience. The profitability is assessed through energy arbitrage, operational revenues, and energy costs, noting improvements with seasonal effects and higher grid capacity.
The results show that the switchable battery configuration can effectively minimise the required investment costs because of the smaller number of necessary carrier units mobilising the battery units. A switchable battery setup with 3x270 kWh batteries and 2 carriers is identified as cost-effective for public and workplace demand, with a potential increase to 340 kWh for higher returns despite 20% more investment. The sizing process is reiterated for another demand scenario consisting of a private charging load and 260 kWh capacity is highlighted as a cost-effective choice, while the profits can be improved with 310 kWh capacity.
The thesis further discusses the mobility necessities of the system and the performance requirements of the powertrain. To maintain grounding, the study simulates the parking service area of P1 at the TU Delft campus. A driving cycle is developed by taking site measurements and also considering safety concerns and standards. Consequently, energy consumption and maximum power requirement are calculated by also integrating a weight estimation methodology regarding the main components of the system.
Lastly, the thesis introduces different power converter topologies that can act as a bridge between the system and EVs. As a consequence of a comprehensive analysis of different converters and the findings reported in the literature, various topologies are suggested to be used in different cases.
The Hyperloop transportation system has emerged as the fifth mode of transportation, offering an energy-efficient, fast alternative for freight and passenger transportation. However, to successfully establish the Hyperloop network, an extensive tube infrastructure would need to be constructed with requirements of being safe, sustainable, and cost-effective. At the time of this project, various tube designs and materials have already been examined and evaluated; given its preliminary stage of development, new design ideas are rapidly emerging. Engineers are faced with two fundamental challenges: firstly, defining safety limits, and secondly, establishing the balance between the safety, environmental footprint, and operational efficiency of hyperloop infrastructure.
The Hyperloop Skeleton tube design is the latest addition to the integral designs that holds great potential in terms of weight efficiency. The aim of this research is to determine the applicability and efficiency of the newly proposed tube design and to evaluate structural performance to imposed loads.
For the design evaluation, the study uses a numerical approach. Skeleton tube design is initially disassembled into individual components, which are analysed separately to identify potential weaknesses of the design as well as to predict their behaviour within the assembly. After that, the study conducts the analysis of the assembly. The initial design lacked rail support design; thus, a design is proposed and implemented in the model for the global analysis. Within the assembly, the research identifies critical sections and design weaknesses. In accordance with this, it proposes and analyses a new ring-to-stringer connection design. Additionally, a comparison study has been conducted with the conventional (plain) tube design, currently used at the European Hyperloop Centre (EHC) [2].
Based on numerical results, the skeleton tube design is conditionally satisfactory in terms of ultimate and serviceability limit states. The design can resist the main load case – vacuum pressure. Nevertheless, the slender components and thin plates make the tube susceptible to plate rupture or penetration if exposed to environmental actions; thus, making the hyperloop system vulnerable to accidental and impact loads. Moreover, the elastic strength capacity of rings, which are primarily in compression and are therefore critical components, is nearly reached. An initiation of local plastic response is observed, yet due to integral design, the stresses distribute among components; thus, it does not progress into a fully plastic response. Based on these findings and considering that dynamic loads are yet to be assessed, it can be projected that a strength capacity will be exceeded in further research.
The proposed steel bracket design for ring-to-stringer connection provides an alternative to welded connections. It improves stress concentrations within the ring, and considering that it is a bolted connection, further contributes to the ease of assembly, maintenance and the demountability aspect. However, the requirement for 288 such connections per 16-meter-long tube section might significantly increase the total cost of skeleton tube design.
Based on the comparison study, it is proven that the conventional tube design performs better in terms of structural performance under the considered loading conditions. However, in a controlled environment with the absence of external actions, the skeleton tube design could efficiently operate. In this case, a material efficiency of 28% can be achieved if the structure supports the rails and the pod, and up to 37.8% if the tube is solely used for vacuum pressure retention.
Emerging technologies, currently in the process of development and yet to demonstrate their contribution to a more sustainable future significantly depend on the performance and success of their initial prototypes and real-world applications. Skeleton design offers a cutting-edge design, which is on the safety – sustainability spectrum drastically leaning to the latter. A secondary protective structure is required for consideration of the skeleton design in the hyperloop application. The design can nonetheless be viable for other applications, which operate in a safe and controlled environment, with the absence of external loads. This research lays a foundation for any further research on the skeleton tube design.
By acknowledging the social domain in the decision-making of top-ups, it can guide future participation processes to be more inclusive and effective, accelerating the implementation of successful top-ups.","top-up; vertical extension; densification; participation process","en","master thesis","","","","","","","","","","","","Metropolitan Analysis, Design and Engineering (MADE)","Master Thesis",""
"uuid:a74ff329-619b-4872-aec4-973cc09a02de","http://resolver.tudelft.nl/uuid:a74ff329-619b-4872-aec4-973cc09a02de","Reliability updating of a quay wall using measurement data: A case study of a Maasvlakte quay wall in the Port of Rotterdam","Klerks, Joosje (TU Delft Civil Engineering & Geosciences)","Jonkman, Sebastiaan N. (mentor); van Eijnden, A.P. (graduation committee); Habets, C.J.W. (graduation committee); Roubos, A.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","In common practice, quay walls are engineered to fulfil their services for a minimum lifetime. However, in many cases, quay walls are designed stronger than minimally required, which means that the quay wall could be able to serve its purpose over a longer period or endure higher loads. In general, the optimization of quay wall designs or the assessment of the extension load-bearing capabilities, particularly in existing structures, is substantiated through probabilistic design methodologies.
This study investigates the operation of reliability updating with deformation data to enhance the operational lifespan and load-bearing capacity of existing quay walls. Traditionally, quay walls are designed with predetermined probabilities of failure based on preliminary information gathered through desk studies and on-site investigations. Observations of existing structures provide new information on the actual deformation behaviour. This study acknowledges the conservative assumptions in initial designs, potentially resulting in concealed geotechnical and structural capacities. It introduces a novel approach involving reliability updating using monitoring data from 'smart' quay walls equipped with advanced sensors. These sensors, measuring especially lateral deformations, provide input for the updating process in a Bayesian model.
Application of this methodology is demonstrated through a theoretical and an actual case study, including the Sif quay wall in the Port of Rotterdam (Maasvlakte II).
The theoretical case study validated the methodology. This was done by updating two initial (prior) distributions for the friction angles of two soil layers using the observed maximum deformation for a combination of predefined values of the friction angles. The updated (posterior) distributions converged towards the predefined values and the distributions reduced in variation or became more informed. These findings affirmed the overall operation of the intended method and proved the efficiency and accuracy of the addition of metamodelling. However, the success of the metamodel appeared to strongly rely on appropriate settings for the specific situation.
For the case study of the Sif quay wall, its deformation behaviour was analysed for three different load cases accounting for the effect of excavation, the effect of water level fluctuations and the effect of top loading. The most recent deformation measurements, together with the knowledge of past deformation behaviour, have proved most useful for updating as all aspects contributing to the lateral deformation of the quay were present. In the updating process of the Sif quay wall case study, six stochastic variables were analysed: the strength (friction angles) and stiffness parameters (stiffness moduli) of three influential soil layers. Within the scope of this study, an increase in one or both parameter types means that the structure may have a higher functional capacity than expected, in the form of moment or normal force capacity.
Here, the strength parameters proved more prone to updating than the stiffness parameters and showed a significant increment. The initial parameter uncertainty indicated by the standard deviation was found to have minimal impact, but larger discrepancies between predicted and observed deformations led to more significant updates.
The quay wall at the Sif terminal appeared to have a negligibly small failure probability, even before updating. Therefore, the impact of updating was not measurable in terms of the reliability index, but the outcomes of the limit state function distribution were significantly impacted: their variation was reduced, and the overall distribution moved away from the point of failure.
Regarding cost-effectiveness, the risk mitigation for existing walls after monitoring and reliability updating might be limited. However, the potential for significant steel reduction in new quay wall designs based on updated soil information highlights the value of reliability updating. The approach of this study may lead to more efficient and sustainable quay wall construction practices.
The study also acknowledges limitations in the simplification of the soil model compared to the actual situation and the consideration of one single failure mechanism. Another important factor is the limited level of knowledge on the quay wall deformation conditions, such as loading magnitudes and potential time-dependent effects, compared to the minimized model uncertainties. This aspect should be taken into account when evaluating the results of the update results. Recommendations for further research include:
• To achieve a more realistic representation of quay wall behaviour, it is recommended to incorporate various failure mechanisms, including geotechnical failure, as real-world failures often involve the interplay of multiple mechanisms.
• For a more robust prediction, the model should explore a wider range of stochastic variables, including factors like bed level, water level fluctuations, and top load.
• To enhance the accuracy of the updated parameters, it is recommended to acquire additional measurement data through on-site loading tests or by implementing smart bollards for real-time loading information.
• Investigating the correlation between the stochastic variables is crucial for understanding their combined influence on the model's predictions. This analysis will lead to more accurate results.
• To maximize its practical value, the model should be extended for applications such as berth deepening or designing for increased top loads.
In summary, this research highlights the potential of reliability updating with deformation data, offering more insights into a possible increase of a quay wall's capacity. By understanding a quay wall's reliability, port authorities can optimize its use and extend its service life, reducing environmental impact and bringing economic benefits.
For this study, a model has been constructed to simulate the Dutch electricity and hydrogen market in 2040. Four different energy systems have been modelled, differing mainly in the extent to which the Netherlands is self-sufficient in their electricity and hydrogen demand. The model is constructed in Linny-R: a graphical modelling tool specifically designed for the formulation of Mixed Integer Linear Programming (MILP) problems, particularly for Unit Commitment (UC) problems.
Firstly, using the model, the required underground hydrogen storage capacity in 2040 in the four different energy systems has been determined. The performance of different storage configurations, consisting of a certain number of short-cyclic salt caverns in addition to a certain policy for seasonal storage in gas fields, has been compared, and it has been concluded that only when a large installed capacity of solar and wind energy is placed in the Netherlands, the preference is for a mid-seasonal storage policy. In the other energy systems, the preference was for a low-seasonal storage policy.
The second part of the research focuses on the financial feasibility of underground hydrogen storage facilities. The average system costs and profits have been mapped out. For the most plausible energy system, it has been determined that the storage facilities in 2040, when they have to generate their income purely based on market prices, are not profitable. To recoup the investment in salt caverns, the government will need to subsidise 0.26 €/kg of hydrogen.
In addition to the insight that subsidisation will be needed to kickstart investments in underground hydrogen storage, some other important insights for policymakers have emerged. The installed capacity of hydrogen turbines has a significant effect on both the operational system costs of the entire energy system and the economic feasibility of the storage facilities. Furthermore, it has been found that in an energy system already dominated by green electricity and green hydrogen, adding additional storage facilities does not result in further CO2 reduction. As long as the carbon capture rate is limited to 90%, approximately 10,000 kton of CO2 will still be emitted annually. To become fully carbon-neutral, the Dutch government must therefore consider negative emission measures such as reforestation and ecosystem restoration.
One of the core strategies identified by the Dutch government to facilitate the transition towards more systemic and efficient infrastructure asset management is to cluster bridge maintenance projects. Project clustering involves consolidating multiple maintenance projects with similar characteristics or geographical proximity into one portfolio. Existing research has highlighted the positive impacts of project clustering on project-specific performance indicators. However, there is a lack of studies examining the broader implications of different clustering strategies on the entire transport system. The current literature predominantly comprises retrospective studies analyzing historical project data, providing valuable insights into project clustering effectiveness but falling short of assessing its influence on future infrastructure system behavior. This research aims to bridge this gap by conducting an exploratory modeling analysis to explore the effects of different maintenance cluster strategies on the performance of the transport infrastructure network.
This thesis employs Entity-based System Dynamics (SD). Entity-based SD is a relatively new modeling methodology and can be seen as a combination of agent-level (ABM) modeling and macro-level (SD) modeling. This combination allows for the modeling of the (spatial) behavior and attributes of individual bridges, roads and regions, while retaining the capability of doing macro-level analyses. Furthermore, as the bridge maintenance problem is subject to deep uncertainty, Entity-based SD was paired with the Exploratory Modeling and Analysis methodology. This allows for the exploration of the repercussions of various combinations of assumptions about uncertain factors in the system. To allow for the combination of the two methodologies, a novel EMA Workbench-Ventity connector was constructed for this thesis.
Because Entity-based SD is still a relatively novel methodology, there is a lack of spatially explicit applications within the existing scientific literature. As such, this thesis pursues two objectives, (1) developing, and reflecting on the added value of a novel spatially explicit Entity-based SD modeling method when modeling the effect of bridge maintenance cluster policies on the wider infrastructure system, and (2) identifying maintenance cluster policies that are effective at facilitating a steady and predictable maintenance capacity demand. To pursue these two objectives, an abstract network was constructed using the Entity-based System Dynamics methodology.
The analysis of the model outcomes shows that the model was able to generate spatially explicit relationships between traffic flows and bridge degradation. The model was also able to capture the performance of maintenance cluster strategies and showed expected behavior. Six policies were tested with the model, three variations of geographical clustering (small, medium, and large), construction type clustering, construction year clustering, and a no clustering policy. The model results indicate that larger maintenance clusters bring about more fluctuating changes in capacity utilization, while smaller clusters lead to a higher total number of expected projects over a 100 year simulation period. Larger clusters also result in a higher average load capacity for the bridge set, mainly due to increased preventive maintenance. Despite larger clusters generally outperforming no cluster policies, their overall effectiveness is diminished, especially concerning the critical outcome of change in capacity utilization. A geographical cluster policy with small clusters, an average of 1.9 bridges per cluster, stands out for its more stable maintenance capacity utilization compared to a no cluster policy option and slightly better performance in other key outcomes.
As such, policymakers should implement policies that encourage the formation of small maintenance clusters. However, as the network specification plays a crucial part in the performance of cluster policies, policymakers should adopt a flexible approach, considering the specific characteristics of the infrastructure network when formulating maintenance clustering policies. Future applications for the model could add additional external effects to the model, introduce finite maintenance capacity and a finite maintenance project size, or include dynamics in the model that allow for the modeling of traffic jams.
At a methodological level, it can be concluded that Entity-based SD is a suitable approach to infrastructure modeling. The added value of the novel spatially explicit Entity-Based SD approach can be described in five points. First, the method holds a high degree of replicability. Because entity types can be independently defined, infrastructure components can be individually modeled and reused in other models. Additionally, the method makes use of externalized network initialization data, which separates the dynamics of infrastructure components and the network specification data, allowing for components to be altered individually without the need to alter the other. Second, the computational requirements of the approach are limited compared to other infrastructure modeling approaches. Third, similar to SD modeling, the model is made up of a clear model structure with stocks, flows, and causal links which enhances communicability and supports group model building with stakeholders. Fourth, as an extension of SD modeling, the method provides a holistic approach to infrastructure modeling, which means that it enables the modeling of not only individual infrastructure components but also the broader system in which these components operate. Lastly, the approach is capable of coping with high degrees of uncertainty due to the EMA Workbench connector that was constructed for this thesis.
Based on the arguments presented in this thesis, the novel spatially explicit Entity-based SD approach is considered to be a suitable new avenue for infrastructure modeling. However, this study should be considered as a first investigation into this approach and is therefore incomplete. Although the abovementioned added values have been identified during the course of the thesis, some limitations and future improvements still exist. Firstly, the Entity-based SD methodology offers limited documentation, as the maturity of the approach is low. Secondly, the approach is not meant to generate precise forecasts. As such, if this is the objective of the modeler or stakeholder, Entity-based SD should not be considered as a candidate approach. Future applications of this modeling approach could look at the performance of the approach when modeling larger networks. Therefore, spatial Entity-Based SD should not be seen as a replacement for current infrastructure modeling approaches. Rather, it should be viewed as a new addition to the scientific field of infrastructure modeling.
Therefore, this study aims to investigate the transport impacts of crowdshipping service for outlier parcels, which are defined as the parcels with high environmental impacts. A case study is conducted in The Hague. First, the parcel carbon footprint is calculated to segregate the outlier parcels. Then, a public transport-based crowdshipping delivery scenario is proposed, with parcel lockers at train stations as the transfer points and train travellers as the potential occasional couriers. The simulation results show that outsourcing the outlier parcels to crowdshipping service is beneficial to the transport system and prioritising outlier parcels of logistics service providers with low market shares can achieve more savings in transport and higher service efficiency.","Last-mile delivery; Crowdshipping; simulation; Case study; City Logistics; Parcel Locker","en","master thesis","","","","","","","","","","","","Transport, Infrastructure and Logistics","",""
"uuid:1053611a-cd54-4dd1-8ece-a9d14a80cf4a","http://resolver.tudelft.nl/uuid:1053611a-cd54-4dd1-8ece-a9d14a80cf4a","Measuring and quantifying shunt currents in an alkaline water electrolyser shortstack","Roest, Dirk (TU Delft Electrical Engineering, Mathematics and Computer Science)","Haverkort, J.W. (mentor); Delft University of Technology (degree granting institution)","2024","Hydrogen is used in a variety of industrial applications and can function as a green energy carrier, if produced sus-tainably. Alkaline water electrolysis holds great promise as a production method for green hydrogen, potentially playing an important role in the energy transition. The performance of this technology depends significantly on its electrical efficiency. In some industrial-scale green hydrogen plants, multiple electrolysis cells are coupled together in series or in parallel to form a stack. These electrolyser stacks are being fed with a liquid electrolyte, often a KOH solution, which acts as a good conductor for ions to move between electrodes. The channels through which the electrolyte and gas products are transported in and out of the stack are usually connected to each other via manifolds. Electrolyzer stacks frequently encounter a problem known as shunt current, which is alternatively described as leakage, bypass, or parasitic current in various studies through these channels and manifolds. Math-ematically describing the magnitude and nature of these shunt currents has been the topic of a variety of studies. Being able to adequately measure and quantify shunt currents in an actual stack remains a challenge. This study aims to measure and quantify shunt currents in a novel electrolyser stack design by the employment of hydrogen reference electrodes, copper or silver pseudoreference electrodes, and a magnetic current clamp. Numerous ex-perimental findings have been coupled with mathematical models, imaging and theoretical expectations offering detailed insights in the behaviour of shunt currents with varying external factors. The variable parameters in this shunt current research are the applied current density to the stack and the applied liquid flow rate, by an external pump. The performance of hydrogen reference electrodes, copper and silver wires separately, to measure potential dif-ferences in an electric field generated in the highly alkaline environment of a 6M KOH solution was validated. It was found that the hydrogen reference electrodes functioned accurately and stable, giving conductivity results of the electrolyte 7.5 % above measurements performed with a conductivity probe. The copper wires functioned less predictable and stable, giving values 16 % above the validated value, with a larger spread and less reproducibility. The silver wires showed great potential, providing a value of 3 % above the validated value, but showed less stability in measuring constant potential differences. The plain copper and silver wires only functioned for short term measurements, where a potential difference between a baseline potential was the only predictable outcome. Both lacking a stable redox potential, they were found not suitable for accurately measuring potential differences inside the stack. The hydrogen reference electrodes proved to be useful in quantifying average manifold shunt currents, however leaving uncertainties as to total shunt currents in the experimental set-up used in this research. The magnetic current clamp was used to measure the current running through the external wiring between cells, from which the shunt current could be inferred. These measurements showed much potential in quantifying total shunt currents, but showed a large standard deviation between measurements due to the instantaneous nature of the measure-ments, alongside unpredictable electrode connections interfering with the outcomes...
Thus, the aim of this research is to develop an improved trajectory optimization method, thereby ensuring accurate geo-referencing and alignment of the survey data. This thesis proposes a newly developed methodology to achieve this aim: features are extracted from point cloud surveys, matched and utilized by g2o optimizer and GNSS processing software to optimize the trajectory. The development is described and results are evaluated on two different scales - locally, within a point cloud tile and globally, within a sequence of tiles. It is done by using Glasgow's underground railway network as a test case.
Results from the implementation demonstrate significant improvements in trajectory accuracy - a misalignment of point cloud data was reduced from a 1.5 m to a cm level within an optimization time frame that took approximately 10 hours. This improvement in accuracy was present under different complex environments using both the local and global versions of the algorithm. However, the area near the railway tunnel entrance saw a limited benefit from the implementation of the proposed algorithm.
In conclusion, the developed trajectory optimization algorithm optimizes the trajectory and improves the alignment of the survey data. Moreover, the method outperforms the currently employed solutions by being automatic and applicable in different environments. However, further research is required to optimize the algorithm itself (accuracy and computationally speed of the algorithm) and to more accurately define its limitations in terms of the surveyed environments.","GNSS; IMU; LiDAR; Point Cloud; SLAM; Trajectory Optimization","en","master thesis","","","","","","","","2026-03-18","","","","Geoscience and Remote Sensing","","55.85844788381607, -4.2583973200779415"
"uuid:4fe7cd89-5f7c-468b-8f8b-d2c493be9386","http://resolver.tudelft.nl/uuid:4fe7cd89-5f7c-468b-8f8b-d2c493be9386","Physics-informed machine learning for nowcasting extreme rainfall","Yin, Junzhe (TU Delft Electrical Engineering, Mathematics and Computer Science)","Dauwels, J.H.G. (mentor); Abelmann, L. (graduation committee); Uijlenhoet, R. (graduation committee); Delft University of Technology (degree granting institution)","2024","The thesis explores an innovative technique for enhancing the precision of short-term weather forecasts, particularly in predicting extreme weather phenomena, which present a notable challenge for existing models such as PySTEPS due to their volatile behavior. Leveraging precipitation and meteorological data sourced from the Royal Netherlands Meteorological Institute (KNMI), the research innovates through the development of a physics-informed neural network. Central to this approach is the implementation of a Physics-Informed Discriminator GAN (PID-GAN), a method that embeds physical principles directly into the adversarial training regime. The architecture is marked by the integration of a Vector Quantization Generative Adversarial Network (VQ-GAN) and a Transformer as the generator, complemented by a temporal discriminator as the discriminator component. Results from this study indicate a notable advancement over traditional numerical weather prediction and cutting-edge deep learning models, underscoring the PID-GAN model's superiority in delivering accurate precipitation nowcasting metrics.","Deep Learning; Nowcasting; Physics informed machine learning","en","master thesis","","","","","","","","","","","","Electrical Engineering | Circuits and Systems","",""
"uuid:fdbca0b0-124e-45e1-8678-e8026c64d42d","http://resolver.tudelft.nl/uuid:fdbca0b0-124e-45e1-8678-e8026c64d42d","Hybrid Modelling in Hydrology Using a Neural Ordinary Differential Equations Approach","Schieren, Jonathan (TU Delft Civil Engineering & Geosciences)","Hrachowitz, M. (mentor); Taormina, R. (graduation committee); Ragno, E. (graduation committee); Visser, Martijn (graduation committee); ter Maat, Judith (graduation committee); Delft University of Technology (degree granting institution)","2024","Conceptual models in hydrology are widely used, allow for easy interpretation and require little data. Machine learning models in hydrology often outperform conceptual models but lack the ease of interpretability, require large amounts of data and and do not obey physical laws. Hybrid approaches aiming to combine the advantages of both approaches are becoming more popular. A Neural Ordinary Differential Equations approach is introduced to combine a differential equation-based conceptual model with a neural network. Additionally, conceptual models and LSTM models are used as benchmarks. The models are tested using the LamaH-CE dataset as well as the E-OBS dataset. In many cases the hybrid models outperform the conceptual model. However, to further improve the performance of hybrid models more research is needed to make the models more computationally efficient and optimized training strategies are required to explore the full potential of the approach.
This thesis situates the Lynetteholm project within the broader context of Copenhagen's historical commitment to sustainable urban development and efficient public transportation systems. It explores the unique challenges and opportunities presented by this ambitious project, particularly in the realm of mobility and transportation. By drawing on comparative analyses with cities like Amsterdam and Venice, which share Copenhagen's characteristic of being intertwined with waterways, the research aims to distill valuable insights into managing urban mobility in water-centric urban environments.
Central to the thesis is the exploration of smart mobility solutions, specifically Autonomous Navigation Systems (ANS) and Demand-Responsive Transportation (DRT), framed within the increasingly popular concept of Mobility as a Service (MaaS). The investigation delves into the potential synergy between these technologies and the existing urban transport framework in Copenhagen, with a particular focus on enhancing the ""Harbor Bus"" service. The envisioned autonomous demand-responsive ferry service (ADRT) is posited as a sustainable, efficient, and user-centered mobility solution that seamlessly integrates with the city's transport network, thereby facilitating the smooth incorporation of Lynetteholm into Copenhagen's urban tapestry.
The proposed ADRT system, characterized by its autonomous operation and demand-responsive nature, is designed to double the capacity of the current Harbor Bus fleet, addressing both the anticipated residential influx in Lynetteholm and the broader transportation needs of Copenhagen's residents. This system not only promises enhanced operational efficiency and reduced environmental impact but also aligns with the city's long-term vision of achieving CO2 neutrality and fostering a ""green wave"" of commuting practices.
Furthermore, the concept of ""Ferry Oriented Development"" (FOD) is introduced as a strategic urban planning approach that capitalizes on the untapped potential of waterways. By developing ferry terminals as focal points of urban activity, FOD encourages the formation of vibrant, interconnected communities that prioritize sustainable transport modes, thereby reinforcing Copenhagen's commitment to environmental sustainability and efficient urban mobility.
In sum, this thesis offers a comprehensive examination of the interplay between urban expansion, sustainable development, and innovative transport solutions in the context of Copenhagen's Lynetteholm project. It presents the design of a conceptual framework for an ADRT system that embodies the principles of autonomy, responsiveness, and integration, thereby contributing to the discourse on future urban mobility. This research provides a nuanced, evidence-based perspective on the deployment of smart mobility solutions in the face of rapid urban growth, offering valuable insights and recommendations for urban planners, policymakers, and stakeholders engaged in shaping the future of urban living in Copenhagen and beyond.","Demand-Responsive Transportation (DRT); Autonomous Navigation Systems (ANS); Ferry Oriented Development (FOD)","en","master thesis","","","","","","","","","","","","Metropolitan Analysis, Design and Engineering (MADE)","",""
"uuid:40c562f9-6d65-4a84-8bed-498ae828d8dd","http://resolver.tudelft.nl/uuid:40c562f9-6d65-4a84-8bed-498ae828d8dd","Limiting microcracks and hydrogen permeability in thermoplastic composites for LH2 storage","van der Helm, Jens (TU Delft Aerospace Engineering)","Sinke, J. (mentor); Atli-Veltin, B. (graduation committee); de Vries, H. (mentor); Delft University of Technology (degree granting institution)","2024","The Netherlands Aerospace Centre (NLR) together with Toray Advanced Composites and 12 other parties take part in the Netherlands liquid hydrogen (LH2) composite tank consortium which is funded by the Netherlands research & development mobility (RDM) Fund. The goal of the RDM project NLR takes part in is to develop a long-life, fully composite LH2 tank for civil aviation. Microcracking and the subsequent hydrogen permeation remain the biggest challenges. This study encompasses three fundamental facets to test and select composite materials: a comprehensive investigation into material behavior, the formulation of a Finite Element Method (FEM) model, and a partial experimental verification of said FEM model. The latter integral component involves an extensive testing system that includes room temperature and cryogenic tensile tests, permeability assessments, and microcrack evaluations facilitated by optical microscopy. During the experiments there is focussed on the critical microcrack density and material selection criteria such as ply thickness.","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:bd2d39ac-028e-4f6c-b56c-050f1ec43931","http://resolver.tudelft.nl/uuid:bd2d39ac-028e-4f6c-b56c-050f1ec43931","Marine Pumped Hydro Energy Storage: Shape design of the reservoir","Wesseling, Lucas (TU Delft Civil Engineering & Geosciences)","Hoogenboom, P.C.J. (mentor); Hendriks, M.A.N. (mentor); Delft University of Technology (degree granting institution)","2024","The offshore renewable energy market is rapidly growing, particularly in wind and solar sectors. The intermittent nature of these energy sources underscores the necessity for offshore energy storage solutions. Among the techniques being explored, Marine Pumped Hydro-Energy Storage (MPHES) emerges as a promising option. This innovative concept operates similarly to artificial lakes, where water is stored and released to generate electricity. In the MPHES system, a seabed-based reservoir is established, in which water flows, driving turbines to generate electricity. During periods of energy surplus, the system is charged by pumping water out of the reservoir...","Energy Storage; Concrete Structures; DIANA FEA; Civil engineering; Structural Engineering; Shape Optimisation; Integral design","en","master thesis","","","","","","","","","","","","Civil Engineering | Structural Engineering | Concrete Structures","",""
"uuid:2fcf9431-dd26-49bf-9d91-8b8052061e3a","http://resolver.tudelft.nl/uuid:2fcf9431-dd26-49bf-9d91-8b8052061e3a","Multi-objective differential evolution optimization of ion beam analysis spectra","Mariën, Simon (TU Delft Electrical Engineering, Mathematics and Computer Science)","Yorke-Smith, N. (mentor); Panichella, A. (graduation committee); Meersschaut, Johan (mentor); Delft University of Technology (degree granting institution)","2024","n the rapidly evolving semiconductor industry, precise material characterization is crucial. This thesis focuses on enhancing Ion Beam Analysis (IBA), a pivotal tool in semiconductor characterization, through the integration of differential evolution optimization. This research proposes a single and multi spectra optimization algorithm approach controlled by a web application. Central to this work is a com- parative analysis of the proposed algorithms to simulated annealing and the DE algorithm proposed by Heller et al. [5]. This analysis shows a good performance of the proposed algorithms and a potential for industry application. The web application offers users a robust, user-friendly, and scalable interface for IBA optimization. By proposing and testing new IBA optimization methods, this thesis contributes significantly to semiconductor technology, offering new methods for material characterization at microscopic level.
This project is a joint project between Imec (Leuven, Belgium) and HZDR (Dresden, Germany).","Differential evolution; Material characterization; Ion Beam Analysis","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:21e5b9c2-3e58-495c-881c-634e67ebe645","http://resolver.tudelft.nl/uuid:21e5b9c2-3e58-495c-881c-634e67ebe645","Sensitivities and where to find them: Domain shift robustness, attacks, and training variations in visual learning","Wang, Z. (TU Delft Pattern Recognition and Bioinformatics)","Reinders, M.J.T. (promotor); van Gemert, J.C. (promotor); Loog, M. (promotor); Delft University of Technology (degree granting institution)","2024","Machine learning aims to solve a task with a certain algorithm or statistical model that is trained on data, with or without labels. As a subcategory of machine learning, deep learning achieves good performance with its flexibility on end-to-end representation learning and architecture design. Despite the successes of deep learning, the output of which can be sensitive to various factors. This work visits three sensitivity factors: distribution shifts, attacks, and human impact.
One factor that can impair the performance of a deep net is a distribution shift between the training data and the test data. Depending on the availability of either data or label, some coping strategies for distribution shifts are domain adaptation, domain generalization, transfer learning and multi-domain learning. We first show how domain adaptation can help to mitigate the gap between historic and modern photos for visual place recognition. We show that this can be realized by focusing the network on the buildings rather than the background with an attention module. In addition, we introduce a domain adaptation loss to align the source domain and the target domain. We thenmove to domain generalization and show that learning domain invariant representations cannot lead to good performance for domain generalization. We suggest to relax the constraint of learning domain invariant representation by learning representations that guarantee a domain invariant posterior, but the resulting representations are not necessarily domain invariant. We coin this type of representation as hypothesis invariant representation. Finally, we study multi-domain learning and transfer learning with the application of deep learning to classify Parkinson’s disease. We show that a temporal attention mechanism is key for transferring useful information from large non-medical public video datasets to Parkinson videos. Weights are learned for various tasks involved in this Parkinson dataset to decide a final score for each single patient.
A deep net is also sensitive to malicious attacks, e.g., adversarial classification attacks or explanation attacks. Adversarial classification attacks manipulate the classification result while explanation attacks change the explanation heatmap but do not alter the original classification results. We notice that the robustness to an adversarial classification attack is linked to the shape of the softmax function and can be improved by using a polynomial softRmax, which is based on a Cauchy class conditional distribution. This also shows that the performance of deep learning is sensitive to the choice of class conditional distribution. Regarding the explanation attacks, we design several ways to attack the GradCAM explanation heatmap to become a predetermined target explanation which does not explain the classification result.
We further explore the influence of human trainers in hyperparameter tuning during the learning of deep nets. A user study is designed to explore the correlation between the performance of a network and the human trainer’s experience of deep learning. Experience of deep learning is found to be correlated with the performance of the deep net.","","en","doctoral thesis","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:f16dc219-56be-4d03-8733-ff27f3d9a072","http://resolver.tudelft.nl/uuid:f16dc219-56be-4d03-8733-ff27f3d9a072","The Evaluation Of Stereopsis On The Preoperative Surgical Planning For Colorectal Liver Metastases Surgery","Coopmans, Laurent (TU Delft Mechanical, Maritime and Materials Engineering)","van den Dobbelsteen, J.J. (graduation committee); Mieog, J.S.D. (Sven) (mentor); Dijkstra, J. (Jouke) (mentor); Broersen, A. (Alexander) (mentor); van Dam, M. (graduation committee); Dijkhuis, T. (graduation committee); Delft University of Technology (degree granting institution)","2024","Background
The surgical management of Hepato-Pancreato-Biliary (HPB) cancer poses significant challenges, primarily due to the complexity of patients. However, the role of stereopsis (depth perception) in visualizing three-dimensional (3D) anatomical models remains relatively underexplored. Integrating stereoscopic technologies with 3D anatomical modelling holds promise for enhancing surgical planning and navigation, thereby addressing the inherent complexities of HPB surgeries.
Aim
This study aims to evaluate the effect of stereopsis on the preoperative surgical planning of colorectal liver metastases surgery.
Methods
A retrospective study was conducted with participants from the Department of Surgery, Leiden University Medical Centre (LUMC), to investigate the occurrence and severity of symptoms resulting from the use of a stereoscopic display. Subsequently, liver and transplant surgeons from the same department participated in another retrospective study comparing surgical plans for colorectal liver metastases performed stereoscopically with those performed monoscopically, within the same surgeon.
Results
14 out of 18 participants experienced (slight) symptoms from the use of a stereoscopic display, yet no one discontinued the study due to symptoms. In the subsequent study on the effect of stereopsis on preoperative surgical planning for colorectal liver metastases, 13 liver and transplant surgeons participated. Relative to a gold standard, there appears to be no significant difference between surgical plans executed monoscopically or stereoscopically. There is also no significant difference in the time taken to create these surgical plans (p=0.401). Despite the absence of significant difference between the plans, surgeons do express a (strong) preference for stereopsis in locating the tumor (61%), determining the surgical plan (61%), and assessing vascular involvement (69%).
Conclusion
It is evident that surgeons have a preference for stereopsis in visualizing 3D models, although our study found no discernible differences in outcomes between monoscopic and stereoscopic preoperative planning for colorectal liver metastases surgery. Future research is recommended to compare surgical plannings based on conventional two-dimensional imaging alone with conventional two-dimensional imaging supplemented by additional stereoscopic 3D models. This comparative analysis could offer further insights into the potential advantages of integrating stereoscopic technology into preoperative planning practices.","Stereopsis; Preoperative Surgical Planning; hepatopancreatic-biliary surgery","en","master thesis","","","","","","","","","","","","Technical Medicine","TM30004; 35 ECTS",""
"uuid:7ce61cbc-3f83-4ab5-9953-899ccab70a59","http://resolver.tudelft.nl/uuid:7ce61cbc-3f83-4ab5-9953-899ccab70a59","Learning Interpretable Reduced-order Models for Jumping Quadrupeds","Buriani, Gioele (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Cognitive Robotics)","Della Santina, C. (mentor); Babuska, R. (graduation committee); Liu, J. (graduation committee); Delft University of Technology (degree granting institution)","2024","This work introduces a novel methodology for the development of interpretable reduced-order dynamic models specifically tailored for jumping quadruped robots. Leveraging Symbolic Regression combined with autoencoder neural networks, the framework autonomously derives symbolic equations from data and fundamental physics principles capturing the complex dynamics of jumping actions with high fidelity. This approach significantly reduces model complexity while enhancing interpretability, facilitating deeper insights for legged robotic applications. The efficacy and accuracy of the proposed models are validated through comprehensive experimental studies, marking a substantial advancement in the design of agile and efficient legged robots. This research demonstrates the outperformance of a learned 2D model compared to existing template models such as the ASLIP. Also, an analysis of the dimensionality of the learned model is conducted showing the overarching tradeoff between accuracy and complexity. The method is validated on different simulated quadrupeds and an actual hardware robot.","Quadruped robots; Dynamic modelling; Symbolic regression; Autoencoders; Machine Learning; Interpretability; Reduced-order models","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:357c4d0f-7712-4343-99bb-018d5e654d1f","http://resolver.tudelft.nl/uuid:357c4d0f-7712-4343-99bb-018d5e654d1f","Tidal phase differences in multi-branch systems and their effect on salt intrusion","de Wilde, Hans (TU Delft Civil Engineering & Geosciences)","Pietrzak, J.D. (mentor); Kranenburg, W.M. (mentor); Huismans, Y. (mentor); van Prooijen, Bram (mentor); Hendrickx, G.G. (mentor); Delft University of Technology (degree granting institution)","2024","The Hollandsche IJssel plays an important role in the freshwater provision of the province Zuid-Holland. Consequently, for Rijkswaterstaat it is key that salt intrusion is minimal in the Hollandsche IJssel. Recent studies noted that salt intrusion in the Hollandsche IJssel is limited due to a phase difference between tidal velocities in the main channel, the Nieuwe Maas, and the side channel, the Hollandsche IJssel. Earlier research investigated the impact of phase differences between branches and found it can lead to increased dispersion in the main channel, through a process known as tidal trapping. At the same time, this phase difference can prevent the saltiest water from entering the side channel, as was found at the Hollandsche IJssel. Because of this role, it is relevant to find out how this phase difference may be influenced by sea level rise, more extreme river discharges and particularly how it depends on the geometry of the main and the side channels. Especially the latter could help Rijkswaterstaat to minimize salt intrusion at locations relevant to freshwater intake, such as the Hollandsche IJssel.
The main objective of this thesis is to investigate how the geometry of the side and main channel influences the tidal phase difference between these two channels, and how this may impact the salt dispersion in the side channel. For this, an analytical model is developed describing harmonic wave propagation in multi-branch systems and this is used next to results from a 3D numerical model for the Rhine Meuse Delta (RMM3D). First, the influence of changes in geometry and forcing is systematically investigated for a network containing a single junction. This shows that the length and depth of the side channel are the most significant variables. The depth is one of the main variables impacting friction, which governs the type of wave which can form in the system. A decrease in friction allows a wave to transform into a standing wave pattern as the return wave becomes more important, while increased friction transforms it into a propagating wave. The length also controls the type of wave which can form as it determines the distance along which the friction can work. Additionally, the length also governs potential resonance in the side channel.
Next, the phase differences of the M2, M4 and M6 tide are determined for the junction with the Hollandsche IJssel in the Rhine Meuse Delta (RMD) based on the RMM3D model. The main tidal constituent regarding tidal trapping was found to be M2. However, this does not fully represent the time difference between flow reversal at the Hollandsche IJssel and the Nieuwe Maas, which was found to be around 75 minutes. Additionally, the phase difference at the Lek was investigated. For the M2 tide at the Hollandsche IJssel and Lek, a phase difference of 55⁰ and 31⁰ was found, respectively. These phase differences prevent salt intrusion in the respective side channels. The inflow of the side channels starts while the main channel still flows to the sea during the ebb. At this moment, the salt concentrations in the main channel have already returned to background levels...","Phase difference; Hydrodynamics; Analytical model; Rhine-Meuse Delta; Hollandsche IJssel; Lek","en","master thesis","","","","","","","","","","","","Civil Engineering | Hydraulic Engineering","","51.906134, 4.557591"
"uuid:626bc0e8-d14e-45f2-9065-719d32781b71","http://resolver.tudelft.nl/uuid:626bc0e8-d14e-45f2-9065-719d32781b71","Reducing Emissions: Parameter Sensitivity Analysis for the Conceptual Design of Military Transport Aircraft","Gebhard, Ganesh (TU Delft Aerospace Engineering)","Yin, F. (mentor); Steinert, P. (graduation committee); Delft University of Technology (degree granting institution)","2024","The escalating concerns surrounding climate change underline the importance of examining greenhouse gas (GHG) emissions across various sectors, with aviation causing approximately 1.9% of the global GHG emissions in 2020. To this modest figure, the Dutch aviation industry acknowledges its share to the climate impact and has gone ahead to objectify it. It has been shown that there has been a 13% surge in the 2018 total GHG emissions, and of the emissions attributable to the Netherlands, a staggering 75% has been emitted beyond its border. Remarkably 95.3% of these beyond-Dutch border emissions are attributable to its aviation sector. This showcases how a localized issue can have global impact.
This research explores the area of military aviation emissions, focusing on the Airbus A330 MRTT operated by the NATO Multinational MRTT Unit (MMU). While commercial aviation adheres to emissions monitoring policies, military aviation is exempted from such obligations. This research adopts a certain approach, focusing not necessarily on the identification of the 'right' methodology but more on the selection of methods tailored to identified goals. The core objective is a sensitivity analysis of emissions and climate impact concerning aircraft design and mission parameters.
In collaboration with the MMU and the Royal Netherlands Air Force (RNLAF), this research uses real-world data for model validation. This research addresses key questions around design and mission parameters with the focus on engine performance modeling, emissions modeling and sensitivity analyses.
The report is structured into four chapters.
The first chapter discusses the literature and background of emissions in commercial and military aviation. The focus will be on the critical role of emission and that of climate impact modeling.
The second chapter outlines the methodology, overall emission model reviews and a climate impact evaluation using Average Temperature Response (ATR).
The third chapter includes the validations using flight data and an external software tool for the emissions validations. The last chapter shows the results and a comprehensive sensitivity analysis. The obtained results aim to collectively present insights for Airbus Defence & Space, towards the conceptual design phase of their new military aircraft. This research contributes to the broader prevailing dialog on sustainable aviation.
This research utilizes the fusion of data from a scanning LiDAR with a long-wavelength infrared camera to estimate the relative pose of an unknown uncooperative target. Two separate bespoke pose estimation algorithms, color-ICP and Feature Matching, were developed and tested with laboratory experiments mimicking the close-approach phase with a target under various lighting conditions and relative motion rates. The color-ICP algorithm uses a thermal infrared-infused color-assisted Generalized Iterative Closest Points method, while the Feature Matching algorithm uses computer vision on LiDAR point-infused thermal images to track BRISK feature points in each frame to estimate pose.
In general, the color-ICP algorithm delivered more accurate results throughout the range of experiments, though the fusion was slightly detrimental while the target is being heated or cooled. The Feature Matching algorithm contains a large amount of tunable parameters, making the estimation highly sensitive yet
versatile, demonstrating that harsh lighting conditions can be mitigated with accurate features tracked after the implementation of image processing techniques. Overall, the end product shows promise as a light-agnostic remote sensing and pose estimation solution.
This research contributes to the advancement of active debris removal theory and explores two promising avenues for LiDAR-infrared sensor fusion for pose estimation, laying the groundwork for further iterations exploring this sensor pairing. The resulting use case is a conceivable scenario in which these sensors work together to supplement individual strengths and mitigate disadvantages throughout the approach phase of a debris removal mission.","Active debris removal; Remote sensing; Sensor fusion; LiDAR; Thermal Infrared; pose estimation; unknown uncooperative target","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:a324902b-a157-4244-9cf3-1ca627ef641b","http://resolver.tudelft.nl/uuid:a324902b-a157-4244-9cf3-1ca627ef641b","Cleanroom in an SEM","Jeevanandam, G. (TU Delft ImPhys/Hagen group)","Hagen, C.W. (promotor); Kruit, P. (promotor); Delft University of Technology (degree granting institution)","2024","The work described in the doctoral thesis aims to enhance the functionality of a scanning electron microscope (SEM) by integrating miniaturized versions of cleanroom tools used in microfabrication. The thesis presents the integration of substrate heating, in-situ thermal atomic layer deposition (ALD), sputtering, and thermal evaporation within the SEM. These techniques are expected to enable fast and efficient fabrication of proof-of-concept devices with minimal resources. The thesis also discusses the challenges, limitations, and future work of the integrated cleanroom processes in SEM.","","en","doctoral thesis","","978-94-6384-541-0","","","","","","2024-03-22","","","ImPhys/Hagen group","","",""
"uuid:d5790618-b9af-4d17-8f2c-e5cb4f3cacc4","http://resolver.tudelft.nl/uuid:d5790618-b9af-4d17-8f2c-e5cb4f3cacc4","Formal Control of an Inverted Pendulum on a Cart via Stochastic Abstractions: Using Interval Markov Decision Processes and Linear Temporal Logic on Finite Traces","ten Voorde, Maarten (TU Delft Mechanical Engineering)","Adams, S.J.L. (mentor); Laurenti, L. (mentor); Delft University of Technology (degree granting institution)","2024","The use of machine learning (ML), especially neural networks, in modeling control systems has shown promise, particularly for systems with complex physics. However, applying these models in safety-critical areas requires reliable verification and control synthesis methods due to their inherent complexity. Formal methods, using stochastic finite state models like interval Markov decision processes (IMDPs), provide a way to analyze and verify these systems against detailed safety and performance specifications defined using linear temporal logic over finite traces (LTLf). Abstraction of ML models into such IMDPs, allows the deriving of formal guarantees on the IMDP that carryover to the underlying ML model.
This thesis focuses on designing a switched controller for a cart-pendulum system using neural network dynamic models (NNDM) by formal control synthesis, validating it through formal verification methods. The methodology includes modeling the system behavior under different controllers, abstracting these models into IMDPs, applying the respective formal methods, and validating the approach through experiments. The aim is to demonstrate the framework's utility in a practical context, comparing different neural network architectures and researching the applicability of formal guarantees to both the models and the actual system.
The main contributions are a practical application of the framework to a specific system, a comparison of neural network architectures for dynamic modeling, and an experiment-based validation of the framework's effectiveness. It confirms that the formal guarantees for abstracted models are relevant to the actual system, providing insights into the framework's potential for real-world applications. The findings suggest areas for further research, particularly in making such frameworks more accessible for practical deployment in safety-critical systems.","LTLf; IMDP; Formal methods; Inverted Pendulum on a Cart; Control Synthesis; Stochastic Abstraction; Neural Networks","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:b662f36f-b60d-4741-90f1-1f9cb8b30c10","http://resolver.tudelft.nl/uuid:b662f36f-b60d-4741-90f1-1f9cb8b30c10","Feasibility study on the integration of a deep learning dose computation algorithm in an automated proton therapy treatment planning system","Graauw, Mitchel (TU Delft Applied Sciences)","Perko, Z. (mentor); Breedveld, Sebastiaan (graduation committee); Delft University of Technology (degree granting institution)","2024","The dose computation algorithm, or dose engine, is one of the fundamental parts of radiotherapy treatment planning. These algorithms predict how the dose will be distributed inside the patient.
Current dose engines are mainly based on either Monte Carlo simulations (MC) or pencil beam algorithms (PBA). MC being very precise, but relatively slow. PBA being quicker, but generally lacking accuracy. Since treatment planning requires both high speed and accuracy, one would prefer MC accuracy with even higher speeds than PBA. A recent study showed a possible solution based on deep-learning called the Dose Transformation Algorithm (DoTA). This deep-learning algorithm is capable of doing MC accurate dose calculations and is faster than PBA (Pastor-Serrano and Perk ́o 2022).
In this project, a feasibility study has been performed on the integration of DoTA as a dose engine in actual treatment planning. The treatment planning system (TPS) in this study is Erasmus- iCycle (Breedveld, Storchi, et al. 2012). This study included the creation of an algorithm to do dose computations with DoTA for any given set of parameters given by the TPS. Subsequently, the dose computations by DoTA have been compared to those computed by Erasmus-iCycle’s current dose engine, ASTROID (Kooy et al. 2010). Analyses on these dose computations included comparisons in a homogeneous water box, alternative homogeneous matter and patient geometries. Two main sources of discrepancy between DoTA and ASTROID where the beam’s range and the beam model used by ASTROID, compared to what DoTA was trained on. Both dose engines likely use a different interpretation of the proton stopping power, leading to range discrepancies up to 14.9% for 200 MeV beamlets when projected in a homogeneous matter of 1000 Hounsfield Units (HUs). Comparing the dose distributions in water, the maximum dose discrepancy around the Bragg peak (BP) for a 80 MeV beam was about 60.0%, due to the width of the beam being larger for DoTA. The mean dose discrepancy in water reached a maximum of 18.9%. In a patient geometry, the range differences made the mean discrepancies go up to a maximum of 22.9%, as expected from the range discrepancies found earlier. Implementation of different gantry and beamlet angles increased the discrepancies, likely caused by the interpolation required to perform calculations under these angles. In terms of distributed energy, the models were closer, with the mean discrepancy decreasing to maximum of 7.1%. Computations of two treatment plan dose distributions showed that the discrepancies arising from this beam model and range difference were to large to achieve viable dose volume histograms. A two lateral beam plan showed the better results of the two plans with an under dosing of 20.8%, likely due to robustness occasionally compensating for the range discrepancy.
In this thesis, I investigated DNA organization and segregation systems in a model system bacterium Bacillus subtilis. I approached this feat both from the in vivo aspect – imaging in a live bacterium, and from the in vitro aspect – observing isolated proteins and DNA molecules. This holistic approach allowed me to gain deep insight into the proteins and mechanisms needed for DNA organization and segregation....","Single-molecule Biophysics; Single-molecule fluorescence; In vitro Assays; Magnetic Tweezers; ParABS; Chromosome Segregation; ParB Protein; Supercoiling; DNA Dyes; ParB-ParB Recruitment; DNA Condensation; Live Cell Imaging","en","doctoral thesis","","","","","","","","","","","BN/Cees Dekker Lab","","",""
"uuid:4a6b3544-c7ce-4456-af3e-000c64d531d7","http://resolver.tudelft.nl/uuid:4a6b3544-c7ce-4456-af3e-000c64d531d7","Variability of the raindrop size distribution: model and estimation uncertainties across different scales","Gatidis, C. (TU Delft Atmospheric Remote Sensing)","Russchenberg, H.W.J. (promotor); Schleiss, M.A. (copromotor); Delft University of Technology (degree granting institution)","2024","Precipitation is a profoundly important meteorological process and a crucial component of the water cycle. Thus, the continuous and reliable monitoring of precipitation at global scale is fundamental for scientific sectors such as numerical weather prediction and hydrology. However, accurately estimating precipitation, its type and intensity at planetary scale remains a notoriously challenging task. While point measurements from rain gauges provide generally accurate direct rain observations, their lack of spatial coverage is a significant limitation. Therefore, global-scale precipitation monitoring heavily relies on remote sensing sensors, such as weather radars (ground-based or spaceborne). Radars are capable of indirectly measuring rainfall over extended domains but with a higher level of uncertainty. For accurate rainfall estimates from radar, the complex microphysical properties of rain must be known or inferred. The drop size distribution (DSD) plays a crucial role by offering valuable insights into the microphysical properties of precipitation and linking radar observations to physical quantities such as rainfall intensity. However, similar to rainfall, DSD exhibits significant variability in space and time. The objective of this PhD thesis is to better understand the small-scale variability of rainfall, contributing to the improvement of quantitative precipitation estimation. In this study various critical aspects around DSD which are often overlooked such as DSD measurements, modeling and retrievals across different scales are investigated.","Drop size distribution (DSD); Rainfall microphysics; DSD retrievals; Rainfall variability; Disdrometer; DSD model; μ-Λ relationship; Scale","en","doctoral thesis","","978-94-6384-545-8","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:96c24d11-8841-456f-90b9-c471bf35e46d","http://resolver.tudelft.nl/uuid:96c24d11-8841-456f-90b9-c471bf35e46d","Design and validation of an ice adhesion set-up: Analysis of ice, surfaces and scatter","Connolly, Ronan (TU Delft Aerospace Engineering)","Garcia, Santiago J. (mentor); Tavaststjerna, M.J. (mentor); Pascoe, J.A. (graduation committee); Bergsma, O.K. (graduation committee); Delft University of Technology (degree granting institution)","2024","Ice accumulation on aircraft surfaces is a prevalent issue, and icephobic coating strategies can be implemented to assist in the removal of or ice on an aircraft. However little is known regarding the effects of novel icephobic coatings and surfaces on ice adhesion strength, which is difficult to measure and quantify, and is typically reported in literature with a high standard deviation and scatter. In this thesis, a reliable set-up for testing ice adhesion strength is successfully designed, constructed, and validated. Using this set-up, it is possible to examine the relationships between various surface parameters and ice adhesion strength, and to analyse the scatter in order correlate the results both qualitatively and quantitatively. Additionally, the influence of material and topology on the adhesion strength and failure mechanisms of ice is investigated.","Ice adhesion; ice; ice testing; ice failure; coatings; validation; design validation","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:4a67e143-0004-48cb-963f-c6c874282a9d","http://resolver.tudelft.nl/uuid:4a67e143-0004-48cb-963f-c6c874282a9d","Sparse Non-uniform Optical Phased Array Design","Yu, Kunlei (TU Delft Electrical Engineering, Mathematics and Computer Science)","Joseph, G. (mentor); Romme, J.P.A. (mentor); Leus, G.J.T. (graduation committee); Driessen, J.N. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis addresses the design and optimization of sparse non-uniform optical phased arrays (OPAs) for advanced automotive LiDAR systems. As autonomous driving technologies advance, the demand for high-resolution, reliable, and compact LiDAR systems has become increasingly critical. Traditional uniform OPAs, while effective, face limitations regarding power consumption. This work introduces an innovative approach to designing sparse non-uniform OPAs that achieve desired performance metrics essential for automotive applications, including beamwidth, field of view, and sidelobe levels, while minimizing element count and, consequently, energy consumption.
Through mathematical modelling and simulation, we formulate the problem of sparse OPA design as an optimization problem, leveraging techniques from compressive sensing to identify the most efficient element arrangements. We propose using the sparse array synthesis method to formulate the sparse OPA design problem, utilizing algorithms such as LASSO, thresholding, and iterative reweighted l1-norm minimization to achieve optimal sparse configurations. Our results demonstrate substantial improvements in effectiveness, offering a practical solution to the constraints posed by current LiDAR systems. This thesis contributes to the field by providing a comprehensive framework for the design of sparse non-uniform OPAs, highlighting the trade-offs and benefits of various design strategies. The findings advance our understanding of OPA design principles.","Sparse design; Optical phased array; LiDAR; Silicon photonics","en","master thesis","","","","","","","","","","","","Electrical Engineering | Signals and Systems","",""
"uuid:a3931544-84fe-4fbd-a227-72ad21a3c402","http://resolver.tudelft.nl/uuid:a3931544-84fe-4fbd-a227-72ad21a3c402","Numerical Analysis of Low-Prandtl Jets in Turbulent Forced Convection Regimes","Cascioli, E. (TU Delft ChemE/Transport Phenomena)","Kenjeres, S. (promotor); Kleijn, C.R. (promotor); Delft University of Technology (degree granting institution)","2024","The current need to ensure an effective and prompt transition of the energy sector towards zero-carbon has renewed the interest for nuclear technology. Small Modular Reactors (SMRs) seem particularly interesting for their reduced capital cost, operational flexibility and enhanced safety and security. Different SMR concepts are being developed around the world and the liquid metal-cooled technology is one of the most convincing design options. Liquid Metal Fast Reactor (LMFR) technology was identified as one of the possible Generation IV reactor options too....","Jets; Low-Prandtl Fluids; Forced Convection; Turbulent Heat Transfer","en","doctoral thesis","","978-94-6366-829-3","","","","","","","","","ChemE/Transport Phenomena","","",""
"uuid:88689a12-ea49-4e5c-b20f-d5571e439101","http://resolver.tudelft.nl/uuid:88689a12-ea49-4e5c-b20f-d5571e439101","Decarbonizing Hard-to-Abate Industries in Northwestern Europe: A socio-technical innovation system and techno-economic analysis on the most promising hydrogen sources","Thomson, Owen (TU Delft Technology, Policy and Management)","Korevaar, G. (mentor); van Beers, Cees (graduation committee); van de Kaa, G. (graduation committee); Dickmeis, J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Within the energy transition, green hydrogen stands as a key solution for decarbonizing sectors where direct electrification is not viable. This thesis focuses on the competitive landscape of hydrogen production in North-Western Europe, addressing the technological and geographical competition of locally produced green hydrogen. This research introduces a comprehensive analytical tool to assess the viability of various hydrogen production methods, which are competing value chains of European green hydrogen. By synthesizing institutional, economic, societal, and technical considerations, the model facilitates a direct comparison between different green hydrogen alternatives.
The research commenced by applying Hekkert’s (2011) TIS analysis as a tool for structural analysis to systematically map the system. The goal was to delineate its structure and identify potential key competing value chains within the scope of Europe. This initial phase involved a literature review and interviews to select value chains. The subsequent phase, which also used the TIS as a tool, focused on identifying key drivers and barriers within the system through a functional analysis, utilizing a structured approach to examine system functions. Expert interviews played a pivotal role in this stage, providing an understanding of the system's dynamics. In the last phase, the techno-economic analysis was performed by introducing barrier-driven scenarios. Allowing for insights into the cost components and the overall comparison in the levelized cost of hydrogen for every scenario.
The structural analysis showed that the European Commission set the scope with institutions, allowing for technologically mature low-carbon alternatives in this comparison. The functional analysis revealed the intricate interconnectivity of the system functions, illustrating how drivers and barriers can swiftly transform, reflecting the system's complex status. The primary barrier to green hydrogen adoption is its high cost, creating a deadlock with no demand or supply. Technological advancement and governmental intervention emerged as key solutions to this challenge. The techno-economic results show that the least cost-effective value chain is local green hydrogen, and the most cost-effective value chain is local blue hydrogen. Local green hydrogen faces challenges in competitiveness due to high energy prices and low capacity factors compared to other electrolyzer-based methods. Additionally, compared to other types, like blue hydrogen, it has higher overall investment and energy costs.
The ultimate aim is to navigate through the complexities of the hydrogen system, clarifying how various variables interconnect and influence each other. Tools like the one developed in this research provide a foundation for understanding this complexity. By understanding the impact of governmental interventions and other factors on final prices, stakeholders can engage in more strategic decision-making. To deepen the understanding of the system, it is recommended to conduct further interviews and research, exploring the alternatives within and outside the European system more comprehensively. Investigating what drives prices beyond mere economic factors will offer a clearer picture of their current status and potential future developments. This broader analysis will equip users with the insights needed to make informed decisions, considering both the economic and socio-technical dimensions that shape the hydrogen market's evolution.
This thesis presents a comprehensive study on the aerodynamics of propeller-wing interactions, with a specific focus on leading-edge distributed propeller configurations.
The research was conducted through a comparative analysis, employing a single propeller-wing system, modeled based on the ATR 42/300 as the baseline. This involved comparing a conventional single tractor propeller configuration with a three-propeller leading edge distributed configuration. The methodology used is an unsteady panel method
solver, FlightStream, which is a commercially available software, allowing for an in-depth
examination of the two-way interactions between the propeller and wing (Full interaction mode), and allowing for a force-free wake.
The findings of the study highlighted significant aerodynamic benefits of the leading-edge distributed propeller configuration over the traditional single propeller setup. Notably, there was a 2.5% increase in wing efficiency and a 6.1% reduction in induced drag. Additionally, the propeller efficiency in the distributed system saw a 3% increase compared to the single propeller system. However, it’s crucial to note that these propellers operated at different, non-optimal points, which influences their comparative performance. A key result was the reduced power consumption of the three-propeller system, which required 8.1% less power to maintain steady level-flight conditions than the baseline single-propeller model. This finding suggests potential for increased efficiency in aircraft designs incorporating such configurations.
This thesis systematically defined its fundamental objectives, beginning with the development of a 1D unsteady model for compressible flow in pipeline systems. This model, which served as the basis for subsequent studies, was verified against the existing literature, revealing a 2-4% difference in flow rates and pressure responses. Subsequently, the scope was broadened to include nozzle configurations, which were gradually included in the pipeline model. The model evolved through configurations with one, three, and five nozzles, where larger diameters increased dampening on transient pressure fluctuations. As the research progressed, the final model, incorporating five nozzles, was used as the basis for the scaled Bubble Curtain Technology (BCT) model.
A sensitivity analysis for this study was carried out utilizing parameters from existing research. The sensitivity study specifically emphasized the influence of geometric (hose and nozzle diameters, hose length, nozzle spacing) and operational factors (discharge coefficient, water depth, air flow rate) on the flow dynamic of Bubble Curtain Technology (BCT). The main findings from this research included reducing backflow with smaller diameters and lowering reverse flow with greater discharge coefficients and airflow rates. Changing the hose length and nozzle spacing proved effective for adjusting the required flow rates. The investigation also found that nozzle diameter and discharge coefficient had a considerable impact on nozzle flow rates, with a 2-3% increase over reference values at the maximum value range. Other geometric and operational parameters in the tested ranges had a relatively lower influence on the nozzle flow rates or generated pressure variations.
The scaled BCT unsteady compressible flow dynamics model presented in this thesis is still in its early stages of development, but it can serve as a basis for the development of full-scale pneumatic models that can enhance BCT and lessen the environmental impact of offshore wind farm operations.
The new station design has three entrances and a square which covers the train tracks to add public space to the city of Berlin. Next to that the design contains a central station hall which houses a lounge and a capsule hotel. This will be the first impression people have of Berlin when they arrive by night train.
In response to the sharp decline of seagrass globally, various restoration techniques have been developed and applied; many at limited scale and with limited success. This research focuses on the fluid mechanics and behaviour of seagrass seeds in a sand mixture through physical laboratory experiments. The objective is to establish a technique that incorporates seagrass seeds with sand-capping to develop seagrass restoration methods suitable for upscaling. Due to the limited amount of available seeds, laboratory experiments were conducted to find a suitable proxy for seeds from both intertidal and subtidal Zostera marina populations by tracking and analysing the particle's terminal settling velocity. The average terminal settling velocity of the seeds was 5.97 cm/s, slightly larger than that of sand particles with a diameter of 0.35 mm with a settling velocity of around 5.2 cm/s. Subsequently, the distribution of proxy seeds in the settled sediment of the ""sand-capped layer"" was determined after dispersal in five sediment-water mixtures with a volumetric concentration ranging from 5 % to 30 %. Mixtures with three-grain sizes grain sizes were released (d_{50} = 0.175, 0.35, and 0.52 mm) in a column of 1m and subsequently in a column of 1.5 m, where only the top 0.5m had a sediment-water mixture, while the area below consisted of a column of still water. Results show a general trend: seeds segregate to the top of the settled layer, further enhanced by larger grain sizes and higher sediment concentrations. Tests using the lowest concentrations (5-10 %) showed the best result, for which the largest number of proxies were located at an optimal depth (1 cm-5.5 cm) for protection and germination when using medium coarse and fine-sized sand grains. The results provide valuable insights into the dynamics of seed segregation in sediment mixtures and the hindered settling effect of a bimodal mixture, showing that seeds move differently to sand in a mixture, experiencing more rotation and drifting within a mixture not observed when following trajectories in a still water column. The larger seed particles segregated to the top of the settled layer due to the difference in behaviour with the sediment mixture. Even though the terminal velocity of the seeds in a still water column was larger.","Settling behavior; sedimentation; hinderd settling; seagrass","en","master thesis","","","","","","","","2026-03-20","","","","Civil Engineering | Hydraulic Engineering | Coastal Engineering","Oceankind",""
"uuid:8b54b913-56ac-46c1-9f95-a3bd20f00d80","http://resolver.tudelft.nl/uuid:8b54b913-56ac-46c1-9f95-a3bd20f00d80","Extreme Precipitation Nowcasting using Transformer-based Generative models","Roy, Ankush (TU Delft Electrical Engineering, Mathematics and Computer Science)","Dauwels, J.H.G. (mentor); Fioranelli, F. (graduation committee); Delft University of Technology (degree granting institution)","2024","Extreme precipitation, like floods and landslides, poses major risks to safety and the economy, underscoring the need for sophisticated weather forecasting to predict these events accurately, enhancing readiness and resilience. Nowcasting, which uses real-time atmospheric data to predict short-term weather, is key in addressing this challenge. Traditional nowcasting systems, reliant on extrapolation from rainfall radar observations and constrained by simplistic physical assumptions, often struggle to detect complex, nonlinear weather patterns. This gap has opened the door for deep learning models, which have shown significant promise in improving the accuracy and reliability of short-term weather predictions, making them a focal point of recent research and the basis of this thesis's approach.
This thesis introduces a deep generative model designed for the nowcasting of extreme precipitation events up to 3 hours ahead, utilizing a Vector-Quantized Variational Autoencoder (VQ-VAE) to compress radar data into a low-dimensional latent representation, and an Autoregressive Transformer for predicting future radar images. Additionally, a binary classifier works in conjunction with the Autoregressive Transformer to identify extreme versus non-extreme weather events, using these classifications to inform an Extreme Value Loss (EVL) function. This loss function aims to improve the accuracy of predicting extreme weather events by addressing the data imbalance between normal and extreme precipitation occurrences. The proposed model displays comparable performance with the state-of-the-art conventional methods and other deep learning nowcasting models in predicting extreme events.","Nowcasting; Deep Learning; Extreme Value Theory","en","master thesis","","","","","","","","","","","","Electrical Engineering | Signals and Systems","",""
"uuid:824da837-6d76-4702-9a9e-26b261acd709","http://resolver.tudelft.nl/uuid:824da837-6d76-4702-9a9e-26b261acd709","Feasibility study of Energetics in Nature-inspired Foraging for Lunar Resource Exploitation","Angyal, Zalan (TU Delft Aerospace Engineering; TU Delft Mechanical, Maritime and Materials Engineering)","Mazo, M. (mentor); Menicucci, A. (mentor); Rajan, R.T. (graduation committee); Delft University of Technology (degree granting institution)","2024","The rediscovered interest in space exploration has led to plans to establish outposts on the Moon and beyond. The lunar bases currently planned are to be manned incrementally, with robots performing most work. With new trends in robotics, the use of collaborating swarms has become more abundant. To support lunar operation, a distinct area within swarming, namely foraging, is proposed. Foraging systems have the primary objective of recovering resources. From literature, no foraging framework was found that included system maintenance in its mechanisms. This report aims to answer the question if this is possible while maintaining the benefits of foraging.
The research considers the fundamental act of recharging as its required maintenance task. To evaluate it dynamically, a rudimentary energetics model is included. For the framework of foraging, the work of [Adams] is used as a baseline. The newly proposed system implements an additional recharging region and role to perform recharging activities, both having major implications for role selection and agent operation. Furthermore, to enable navigation based on energy considerations, the experience communicated by mobile agents is amended to include the energy cost of a travelled path. In doing so, additional quality indicators of paths are available making path optimization a more dynamic process resulting in finer population behaviour. Finally, the decaying of beacons is updated and a fallback feature is introduced to maximize agent utilization.
The newly developed foraging system is evaluated using data collected through simulation in Webots. Simulation scenarios included obstacles with impenetrable boundaries and surfaces with increased rolling friction to emulate cost-expensive regions. Qualitative analysis identified all features of the foraging system as expected, both in the exploration and exploitation phase. Quantitative results proved that the system is able to function with the added requirements of recharging, perform path optimization with the additional path quality indicator, and can do so in various types of scenarios. With this, the research statement that foraging functionality is achievable with the practical considerations of robotics is confirmed to hold.","Foraging behaviour; Swarm; Moon Rover; Feasebility study","en","master thesis","","","","","","Double degree in Aerospace Engineering and Mechanical Engineering | Systems and Control","","","","","","Aerospace Engineering","",""
"uuid:28fa87f9-c0b5-456f-8736-e966d7dd150b","http://resolver.tudelft.nl/uuid:28fa87f9-c0b5-456f-8736-e966d7dd150b","In-line Assessment of Lubrication Contamination in Slew Bearings Using Active Ultrasound Spectroscopy","van Eijk, Casper (TU Delft Mechanical, Maritime and Materials Engineering)","Pahlavan, Lotfollah (mentor); Scheeren, B. (mentor); Jovanova, J. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis presents the design and experimental evaluation of an in-line, active ultrasound, condition monitoring setup for the detection of contamination in offshore bearing grease. This process is divided into three distinct research steps. First of all, the influences that affect ultrasound propagation through a bearing grease sample have been investigated through various laboratory experiments. Next, a practical, real-world experiment using a linear bearing has been designed and conducted with the aim of determining the applicability of such an in-line condition monitoring setup. Lastly, the performance of the in-line active ultrasound setup has been evaluated, improvements have been proposed and an overall condition monitoring strategy has been devised.
During the laboratory experiments, various influences on ultrasound wave propagation have been investigated. First of all, design-specific parameters, such as the distance between the sensors, the test-setup material, and the scalability of the measured output voltage have been investigated. Next, the effects of temperature fluctuations, air bubble fluctuations, water contamination and iron particle contamination on the attenuation and velocity of waves for active ultrasound spectroscopy were investigated. It has been shown that air bubble concentration and temperature fluctuations influence the attenuation of the ultrasound in the grease sample. Therefore, the temperature should be kept constant throughout the other experiments. Additionally, the air bubble concentration should be managed through a constant resting time throughout the other experiments. Moreover, it has been shown that a condition monitoring setup employing active ultrasound spectroscopy is able to determine water contamination and iron particle contamination. The highest sensitivity of this contamination detection is located in the first percentage of contamination concentration, showing an amplitude drop of about 0.5dB/mm to 1dB/mm and a change in speed of sound of about 5\% to 15\%. It is however, difficult to differentiate between the different types of contamination using only the attenuation and velocity spectroscopy methods.
The practical, real-world experiment using an operational Huisman linear bearing has illustrated the applicability of using an in-line grease condition monitoring setup in such an environment, by evaluating obstacles such as spatial constraints, location constraints, flowability of the grease and surrounding noise. It has been shown that these obstacles pose minimal challenges for the successful implementation of an in-line grease monitoring setup for effective condition monitoring of offshore bearing grease.
The evaluation of the improved in-line active ultrasound condition monitoring setup has highlighted the strengths and weaknesses of implementing such a setup for offshore applications. A possible combination of the proposed grease condition monitoring method with Acoustic Emission monitoring offers","bearings; condition monitoring; lubrication; ultrasound spectroscopy","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Multi-Machine Engineering","",""
"uuid:5330a6bb-a7b3-4345-ab2d-e82ad3a0e527","http://resolver.tudelft.nl/uuid:5330a6bb-a7b3-4345-ab2d-e82ad3a0e527","MOFs in Motion: Piezoelectricity and Rotational Dynamics of linkers in Metal-Organic Frameworks","Mula, S. (TU Delft ChemE/Catalysis Engineering)","van der Veen, M.A. (promotor); Grozema, F.C. (promotor); Delft University of Technology (degree granting institution)","2024","Metal–organic frameworks (MOFs) are a class of hybrid materials with metal-based inorganic nodes connected by organic linkers via strong coordination bonds. These building blocks can be arranged in 3-D crystalline lattices to synthesize structures with varying pore sizes and a variety of structures (tuneability). These hybrid materials possess exceptional porosity and large surface areas, making them suitable for applications in gas separation and storage, catalysis, and biomedical fields. MOFs also exhibit remarkable flexibility, which is determined by the topology of the framework and the degrees of freedom between bond angles in the organic linkers or coordination bonds between the organic linkers and inorganic nodes. One among the major categories of flexibility in MOFs is the rotational dynamics of organic linkers. The structural dynamics can have a pronounced influence on gas adsorption, diffusion and optical properties. Chapter 4 and Chapter 5 study the rotational dynamics of terephthalate linkers in functionalized MIL-53 MOFs by varying the steric interactions between the linkers using computational methods like ab initio molecular dynamics and classical molecular dynamics. Using the remarkable porosity, structural flexibility, and tuneability features of MOFs as central handles, in this thesis, we aim to study the (a) Piezoelectric properties in MOFs for their application as energy harvesters and (b) Rotational dynamics of linkers in MOFs. It is well-known that MOFs possess a high degree of flexibility and permanent porosity. High porosity of MOFs leads to low dielectric constants. This, together with higher flexibility of MOFs, makes them promising candidates for piezoelectric energy harvesting. Although all non-centrosymmetric MOFs are piezoelectric, their piezoresponse has hardly been studied thoroughly. Chapter 2 and Chapter 3 of this thesis will investigate the structure-property relationships of piezoelectric properties in MOFs through computational methods, and provide design guidelines that can contribute to the development of high-performing piezoelectrics.","Metal organic frameworks; structure–property relationships; piezoelectricity; rotational dynamics","en","doctoral thesis","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:0b3279b8-9f3e-47f6-9fb9-84a4913aeacf","http://resolver.tudelft.nl/uuid:0b3279b8-9f3e-47f6-9fb9-84a4913aeacf","Sports and Menstrual Data for the Health and Performance of Rowers: A research-through-design approach","Rademaker, Julia (TU Delft Industrial Design Engineering)","Sonneveld, M.H. (mentor); Gomez Ortega, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Over the past few decades, there has been a significant increase in the number of professional female athletes. One thing that both professional and amateur athletes can experience is the effects of their hormonal cycles. These hormonal cycles can affect their performance, and in return, their performance can affect their hormonal cycle. However, the underrepresentation of female athletes in sports research has resulted in most sports guidelines not reflecting this possible connection between the menstrual cycle and performance, causing female athletes to be unaware of it.
Athletes should be aware of the connection between their menstrual cycle and performance. Female rowers, in particular, experience a rapid increase in training load and they may be hesitant to discuss menstrual problems with their coach due to their relative newness to the sport, which could cause them to perform less optimally or even unhealthily. This project aims to find an alternative approach to support female rowers to build their knowledge using their sports and menstrual data so that they can perform optimally and healthily.
This project followed a research-through-design approach. This meant that knowledge was generated through design activities (Stappers & Giaccardi, 2014). The design activities were performed in three cycles to iteratively increase knowledge and improve a design that supported rowers in understanding the connection between their performance and the menstrual cycle. Each cycle began with a theoretical investigation of current design practices. These practices were then applied during a practical phase. The primary objective of each practical phase was to deploy and evaluate a design prototype with rowers.
The first cycle of research investigated how sports and menstrual data could be implemented in designs for female rowers. During the practical phase, a digital prototype was used with rowers and the evaluations indicated that the design should be simplified and place more emphasis on visualization. After the evaluation, a co-creation session was held which suggested that the design should explore the value of sharing the data.
The second cycle of research explored how tracking could be a valuable experience for rowers. The findings from the first cycle led to a physical design prototype that was again used and evaluated by rowers. The evaluations of the second phase suggested that the design should take a broader view of performance, and the co-creation of the second phase placed more emphasis on having different levels of activities by the rowers to understand the data. The knowledge generated throughout the project was synthesized into a final design.
The final design was a mobile application that would support rowers in exploring the relationship between their performance and their menstrual cycle. By tracking their mental, physical, menstrual, and contextual data on a daily basis, rowers could reflect on their beliefs about this relationship. In conclusion, the continuous implementation of insights constructed with stakeholders led to a design that could support rowers in understanding their experiences with performance and the menstrual cycle.
In order to further promote this transition, a couple of action points have been identified by Donners (2018) to improve international train travel, ticketing being one of them. Unlike booking a flight ticket - which can be done within just a few clicks - finding, comparing, and booking a train ticket has proven to be a more challenging task. Recent research conducted by the University of St. Pölten in Austria (Preslmayr, 2022) revealed that one third of travellers are unable to complete their booking, highlighting the difficulty of this process. In order to promote the transition from air to rail for short distance journeys, the bookability of international train tickets in Europe needs to be improved.
It is difficult to change a complex system such as the international railway industry, but we can help travellers navigate it. This project aims to do that by redesigning a booking platform and app that support holiday travellers when booking and potentially rescheduling their international train journey in Europe with an intuitive booking process that provides clarity and guidance at every step leaving them feeling confident and excited about their journey.
An iterative design process led to the final design proposal. Created to be intuitive, supportive, adaptive and exciting, this redesign booking platform aims to ensure that every traveller, regardless of their prior travel experience, can easily book a suitable train ticket, leaving them feeling confident and excited about their journey ahead. The booking platform was designed to align with the user needs and decision making patterns. Core features to support this include route characteristics, transfer alternatives and search filters. A travel app was redesigned to complement the booking platform, creating a bridge between the booking process and the train journey. In case disruption does occur, the travellers are supported by the travel app that provides clear guidance for how they can continue their journey.
The user evaluation of the final design proposal shows promising results with an excellent score on its usability according to the adjective rating scale of Bangor et al. (2009) and positive responses from participants. To facilitate this redesigned user journey, some supportive processes need to be improved, including open communication and collaboration between carrier and ticket distributors, updated route information database and an EU wide disruption protocol.
All in all, it is difficult to change a large complex system such as the international train industry, but we can help travellers navigate it. While the railway system is expected to evolve, impactful changes may take time. Meanwhile, optimising services through redesigns can have a significant immediate effect on the travellers experience and provide access to a sizable potential customer segment. Therefore, further exploring and implementing the designs as proposed in this report will improve the bookability of international train tickets in Europe.
Employing agent-based models and simulation techniques enables the study of the emergence and transformation of institutions in a shorter timeframe, with reasonable cost, and under diverse parameters and conditions.
The purpose of this dissertation is to enhance institutional theories by generating new insights, testing hypotheses, and offering support to researchers, historians, policymakers, and social scientists who are studying institutional dynamics. The outcomes of this research may assist in the identification of successful institutions and the comprehension of the factors that contribute to their success....","institutions; institutional modelling; institutional evolution; values; value change; wealth inequality; cooperation; common-pool resources; machine learning; agent-based modelling; modelling purpose","en","doctoral thesis","","978-94-6366-834-7","","","","","","","","","Energie and Industrie","","",""
"uuid:e5b2f672-9dd2-498f-828f-f587b509e298","http://resolver.tudelft.nl/uuid:e5b2f672-9dd2-498f-828f-f587b509e298","High-Temperature Oxidation of Steels Investigating the Kinetics of High-Temperature Oxidation of Steels Through Experimental, Numerical, and Data-Driven Approaches","Aghaeian, S. (TU Delft Team Amarante Bottger)","Bottger, A.J. (promotor); Mol, J.M.C. (promotor); Delft University of Technology (degree granting institution)","2024","H igh-temperature (HT) oxidation plays a significant role in various stages of the steelmaking process, including hot rolling. When exposed to high temperatures and oxygen partial pressure, the steel composition near the surface can be altered as alloying elements deplete. Additionally, the characteristics of the oxide scale, such as thickness and phase composition, vary depending on the oxidation conditions. Due to the experimental challenges of studying such rapid processes under extreme conditions, predictive models are necessary to estimate the substrate surface and oxide scale composition as well as the general oxidation rate of the alloy....","High-Temperature Oxidation; Diffusion-Based Models; Oxidation Kinetics; Machine Learning Models; Oxidation of Steels","en","doctoral thesis","","978-94-6483-837-4","","","","","","","","","Team Amarante Bottger","","",""
"uuid:566ff230-4eae-48b9-8ecc-83a7e981babe","http://resolver.tudelft.nl/uuid:566ff230-4eae-48b9-8ecc-83a7e981babe","Contextualised Value Model: Designing a Robotic Model for Understanding the Context Dependency of Values for Enhanced Conversation Relevance","Saveur, Tom (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Interactive Intelligence)","Neerincx, M.A. (mentor); Oertel, Catharine (mentor); Pera, M.S. (graduation committee); Delft University of Technology (degree granting institution)","2024","The promotion of desirable behaviours, such as socially appropriate or health-promoting actions, can be bolstered through a deeper understanding and awareness of the values that underpin the associated behavioural choices. Various implementations for promoting behaviour change based on goals already exist in Human-Robot Interaction, but, since values are the building blocks for our behaviour an agent can use values for behaviour change. By reflecting on value-related choices in a conversation, a conversational agent can assist in identifying the values at stake. This is particularly significant as these agents serve as accessible and non-judgemental platforms for discussing various concerns in a private setting. Such reflective conversations are time-consuming and may span multiple sessions, necessitating some form of memory (e.g., to reflect on earlier statements and compare the choices made for different situations).
While various robotic agents have been developed to provide behavioural support (e.g., for human health), the absence of a comprehensive memory structure and dialogue strategies capable of fostering personalised, reflective conversations based on the appreciation of certain values and actions in various scenarios through contextualised values remains a challenge. To address this, this study introduces the Contextualised Value Model – a dynamic memory model designed to facilitate value-based reflection and support personalised interactions between humans and robotic agents.
To realise this robotic memory, a conversational agent was designed that could elicit values from participants by discussing various scenarios that happen in daily life and reflecting on said values using perspective-taking and other dialogue strategies.
The evaluation of the Contextualised Value Model focused on three primary aspects: the model's accuracy, the influence on likeability and intelligence, and the effect on participants' value awareness. The model was evaluated during a between-subjects experiment (N=54), consisting of two conditions, one where the robot was able to update and use the Contextualised Value Model, and another one where the Contextualised Value Model was random throughout the conversation.
The outcome measures indicated that the integration of the memory model in conversations led to a personalised and relevant conversation, highlighting the potential of the Contextualised Value Model in enhancing conversation personalisation. Although participants' value awareness and perception of the robot's likeability and intelligence did not significantly differ based on the memory model, the study emphasised the need for extended observation to thoroughly evaluate long-term impacts.
Overall, the Contextualised Value Model presents a promising framework for enhancing personalised interactions in various real-world applications, emphasising the need for further research in this area. The ePartner4all project could be further developed to complement the efforts of primary school teachers and parents in supporting children's self-learning of socially, mentally, and physically desirable behaviours.","Social Robots; Conversational Agents; Memory; Dialogue; Values; Human Robot Interaction; Contexts; Contextualised Values; Reflection","en","master thesis","","","","","","","","2024-03-19","","","","Computer Science","",""
"uuid:7722885a-354c-4bbe-8c84-9c642711e60e","http://resolver.tudelft.nl/uuid:7722885a-354c-4bbe-8c84-9c642711e60e","Designing meaningful interaction with mental workload data","Chen, Yuwei (TU Delft Industrial Design Engineering)","Schneegass, C. (mentor); Dingler, Tilman (graduation committee); Delft University of Technology (degree granting institution)","2024","Our understanding of mental workload (MWL) is still limited compared to well-known physiological data like blood pressure and heart rate. MWL measures the cognitive resources required for tasks against what's available. Innovative technologies offer more comprehensive and objective cognitive data, but their impact on individuals and their tracking needs requires exploration, including how to establish continuous self-tracking behavior.
Therefore, this research aims to understand people's perceptions and thoughts on MWL and explore meaningful MWL self-tracking behavior. It follows three phases: exploratory, validation, and reflection.
In the exploratory phase, literature is reviewed to define MWL and promote self-tracking. Interviews explore users' understanding, motivations, and needs, highlighting issues like data interpretation bias, mistrust, lack of visibility, connection, and use timing.
Validation involves co-design activities, including user tests and surveys. Before user tests, the literature is reviewed for potential solutions. A rapid prototype is designed based on insights and existing metrics from EMOTIV, facilitating discussions with co-designers. Offline surveys track users' workload and stress levels to understand how they record it in their way and their perceptions and confusion between workload and stress.
Reflection combines literature review and validation insights to discuss research findings and propose future design recommendations.
Overall, this research found several barriers and negative attitudes among users toward self-tracking MWL. The main issues include difficulties and misconceptions in understanding MWL, as well as the inability to see the impact of tracking cognitive data. These challenges make it difficult for users to trust MWL data and incorporate MWL tracking into their daily lives. Additionally, this research identifies unique user perceptions of cognitive data compared to physiological metrics like blood pressure and heart rate, informing future design considerations. Ultimately, the research concludes all the insights from the literature review and research to propose several avenues for future design and research.","mental workload; neurotechnology; user research; Self-tracking; personal informatics","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:108458e1-561e-407e-a2c3-0fd747276914","http://resolver.tudelft.nl/uuid:108458e1-561e-407e-a2c3-0fd747276914","Exploring the Possibilities for Collaboration among Dutch mobile Network Operators for C-ITS ready 5G Networks","van den Oever, Mark (TU Delft Technology, Policy and Management)","Annema, J.A. (mentor); de Reuver, Mark (graduation committee); Delft University of Technology (degree granting institution)","2024","Dutch road transportation networks are increasingly facing challenges regarding congestion, safety and environmental pollution. These challenges are intensified by increased urbanization and a growing need for connectivity . In the past, the remedy to most of these challenges laid in expanding the physical infrastructure through new asphalt. Nowadays, information and communication technologies increasingly play a role in infrastructure management by utilizing the available infrastructure more efficiently. With that, Cooperative Intelligent Transport Systems (C-ITS), presents a new beacon of hope. Through C-ITS, vehicles and infrastructure components are connected to realize a safe and efficient flow of traffic. However, the realization and implementation of C-ITS is hindered by legal, technological, economic and organizational challenges that need resolving. One of the main challenges is the absence of a sufficing robust network infrastructure that facilitates the data transmission across devices and road users. Mobile Network Operators (MNOs), are believed to occupy a central role in the future, designing, building and operating these network infrastructures. However, MNOs are already facing challenges in making current 5G network business models profitable. New large investments already loom for MNOs to serve C-ITS, however, without profitable business models, further investments can be pushed to the future which can cause further delay of the deployment of C-ITS. Therefore this thesis aimed to identify conditions and potential forms of collaboration among Dutch MNOs for C-ITS ready networks. A literature review identified potential collaborative forms between private competing companies and provided an initial overview of conditions that can stimulate collaboration. Subsequent interview with stakeholders from the Dutch mobile network operator domain further refined these conditions and identified potential forms of collaboration that potentially can deliver viable collaborative efforts: knowledge sharing, joint R&D and passive network sharing. The research indicated that the creation of a shared vision across both the public and private domain is crucial to get an institutional environment that supports collaboration. On top of that, a sense of ‘needing each other’ needs to emerge between MNO’s in the form of individually unattainable profits. Although, regulation can also act as a pushing mechanism towards collaboration, it can’t force the creation of such networks. The realization of profitable business models is thus crucial for MNOs to build the networks. Further problems in collaboration come from severe distrust among MNOs who also have collaborative experiences which resulted in conflicts and opportunistic behavior. A public body can act as an independent ‘referee’ to mitigate these potential conflicts in future collaborative efforts. With that, a lot of challenges still need to be overcome to realize collaboration between MNOs which makes that collaborative efforts are unlikely to succeed in the near future.","Mobile Networks; 5G; C-ITS; Collaboration; Mobile communication; Telecommunication; Intelligent Transport Systems","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:e5bebc6d-f3de-4155-959e-423f3cefbb9c","http://resolver.tudelft.nl/uuid:e5bebc6d-f3de-4155-959e-423f3cefbb9c","Improving culvert performance: Reducing energy losses by streamlining the entrance and exit of culverts.","van Vliet, Jordy (TU Delft Civil Engineering & Geosciences)","Uijlenhoet, R. (mentor); Hoes, O.A.C. (graduation committee); Uijttewaal, W.S.J. (graduation committee); Wüthrich, Davide (graduation committee); de Jongste, A.L. (graduation committee); Heinhuis, M (graduation committee); Delft University of Technology (degree granting institution)","2024","In Dutch polders, numerous structures like bridges, weirs, culverts, and pumping stations have
been constructed over centuries to manage water levels. These structures play a crucial role in
maintaining water levels within predefined targets. The flat topography of the Dutch landscape
combined with the collective impact of head losses, induced by these structures may result in
flooding of polders during high runoff scenarios. Over time, culverts and bridges may
underperform due to alterations in the water system, increased pressure from climate change,
evolved design rules, insufficient maintenance, and shifts in land use.
A challenge is the potential hydraulic underperformance of structures and the need for their
premature replacement, which is costly. Waiting until the end of their technical lifespan may
contribute to floods. Therefore this thesis focuses on improving existing structures to mitigate
the need for replacement, specifically by streamlining inlet and outlet openings to reduce
energy losses. This leads to the research question of this thesis: “How can the head loss over
existing (too tight) culverts be minimised by adding an inlet or outlet profile and does this lead
to a substantial enhancement in the performance of these culverts, providing a practical option
to postpone the replacement of underperforming culverts?”
To answer this question, the problem is explored by looking into the fundamentals of energy
losses, including entrance losses, friction losses, and exit losses. This gives an understanding of
the conditions under which these losses manifest. However, these basic calculations have
inherent limitations due to their reliance on predefined coefficients. This renders them
inadequate for evaluating the effects of introducing new profiles onto an existing structure.
To overcome this, a flume experiment has been performed to verify whether it is possible to
measure water level differences for various profiles at the culvert entrance and exit. With a 3D
Computational Fluid Dynamics (CFD) model (OpenFOAM), flows around different culverts
are simulated. The results of the CFD model are compared to the flume experiment, after
which the CFD model is used to simulate a variety of scenarios, with different profiles, culvert
dimensions, velocities, and water depths.
As such, this thesis addresses challenges and uncertainties in quantifying head losses in culvert
structures through experimental methods and CFD modelling. Experimental setups struggle
with controlling all flow-influencing parameters, while CFD modelling offers flexibility but
requires careful consideration of uncertainties and limitations. The discussion emphasizes the
complexities of comparing experimental and model results, highlighting trade-offs and
uncertainties in each approach.
The conclusion answers the central research question, confirming that specific profiles added to
culverts can significantly reduce entrance losses up to 65%, thereby lowering headwaters for a
constant discharge.
The recommendations section outlines possibilities for further research, including optimizing
profile dimensions and conducting sensitivity analyses of influential parameters. Practical
recommendations involve aligning large-diameter concrete culverts with the socket end in the
flow direction and integrating groove or rounded profiles during construction for cost-effective
inlet loss reduction.","CFD; OpenFOAM; Culverts; Polders","en","master thesis","","","","","","","","","","","","Water Management","",""
"uuid:29da87dd-681e-4b06-b0d8-58404b21795f","http://resolver.tudelft.nl/uuid:29da87dd-681e-4b06-b0d8-58404b21795f","Online optimization and learning for the optimal power flow problem with unknown objectives","Chai, Anbang (TU Delft Mechanical, Maritime and Materials Engineering)","Grammatico, S. (mentor); Benenati, E. (mentor); Mohajerin Esfahani, P. (graduation committee); Delft University of Technology (degree granting institution)","2024","The Optimal Power Flow (OPF) problem, a cornerstone of power system operations, has gained increased attention since its inception by Carpentier in 1962. OPF is fundamentally an optimization challenge aimed at enhancing electric power system operations within the bounds of physical and operational constraints. Over the decades, various methodologies have been explored to address the OPF problem, adapting to evolving grid complexities and the integration of distributed energy resources. These advancements have brought to the fore issues related to system randomness, fluctuation, and the need for rapid control mechanisms. This thesis introduces a comprehensive solution incorporating an online optimization algorithm tailored for real-time OPF applications. This approach, characterized by minimal computation times, integrates a feedback strategy that obviates the necessity for instantaneous power demand information and employs a Shape-constrained Gaussian Process for the estimation of unknown cost functions. The proposed control algorithm demonstrates robust tracking performance and satisfactory computation efficiency, marking a significant improvement towards optimizing future power networks fraught with increasing size and complexity. Moreover, this work delves into the investigation of various system design parameters, offering insights into potential avenues for enhancing system performance. Through a meticulous examination of these parameters, the thesis sheds light on strategies to refine the integrated system’s efficacy, paving the way for more resilient and efficient power networks.","Online optimization; Power Electrical Systems; Gaussian process; Primal-Dual","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:730c6b30-b8a7-4ba9-8512-4aee1864a54e","http://resolver.tudelft.nl/uuid:730c6b30-b8a7-4ba9-8512-4aee1864a54e","Flexible Runway Scheduling with non-linear Noise Restrictions using a Tabu Search Algorithm","Lagerwij, Sam (TU Delft Aerospace Engineering)","Roling, P.C. (mentor); Bombelli, A. (graduation committee); Ellerbroek, Joost (graduation committee); Delft University of Technology (degree granting institution)","2024","In response to the growing demand for air travel, major airports are approaching critical thresholds in their infrastructure capacity. As the transportation sector continues to expand, it is increasingly important to address environmental concerns that arise from aspects, such as noise annoyance and fuel consumption. This paper aims to enhance the existing Flexible Runway Scheduling Model (FRSM) by integrating a tabu search algorithm with Receding Horizon Control (RHC), introducing non-linear noise restrictions, and implementing more sophisticated fuel burn modeling. The main goal is to evaluate how certain improvements affect the FRSM. To achieve this, a methodology has been developed that uses a multi-objective tabu search algorithm to minimize both fuel consumption and noise annoyance while assigning flights to runways. This study provides a comprehensive analysis of Amsterdam Airport Schiphol (AAS) across different scenarios, ranging from a 1.5-hour flight schedule to a full-day simulation, revealing significant findings. For the 1.5-hour and six-hour scenarios, the tabu search algorithm achieves a 55% and 87.3% reduction in computational time with marginal losses of 0.73% and 0.19% in solution accuracy for fuel burn optimization. Throughout all scenarios, the tabu search algorithm consistently results in a reduction of highly annoyed individuals ranging from 2.14% up to 62.5% compared to the existing FRSM, demonstrating its effectiveness. Moreover, the algorithm minimizes the impact on the flight schedule in terms of delay. Notably, as the flight schedule length increases, the performance of the tabu search algorithm improves compared to the existing FRSM. A sensitivity analysis optimization horizon indicates a positive effect on results, albeit with an associated computational cost. In conclusion, this study showcases the positive impacts of the remodeled FRSM, enabling a faster and more accurate trade-off. The research findings provide valuable insights for optimizing runway scheduling at major airports while balancing efficiency gains with environmental considerations.","Runway Capacity; Tabu search; Metaheuristics; Receding Horizon Control; Fuel consumption; Noise annoyance; Scheduling model","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:3b92d07e-b5b2-49ee-8e33-33c5f98eb309","http://resolver.tudelft.nl/uuid:3b92d07e-b5b2-49ee-8e33-33c5f98eb309","Effect of cyclic wetting and drying on soil erodibility","Dolgov, Alexey (TU Delft Civil Engineering & Geosciences)","Jommi, C. (mentor); Amerlaan, Patricia (graduation committee); Delft University of Technology (degree granting institution)","2024","Cyclic wetting and drying impact the integrity of cohesive clay materials in geotechnical engineering applications. Boom Clay, frequently used in erosion protective layers, presents a critical case study due to its widespread application and the environmental conditions it endures. This research delves into the effects of repeated wetting and drying cycles on Boom Clay’s erodibility, a process that protective layers often undergo during construction and exposure.
Utilizing the Erosion Function Apparatus (EFA), performed experiments targeted changes in the structure and erosion resistance of Boom Clay under cyclic conditions. The test setup was adjusted, improved, and calibrated. It was observed that these cycles induce alterations in the clay’s erodibility, contrasting with the behavior of untreated samples.
The results demonstrated cyclic wetting and drying increases the susceptibility of the material to erosion, and the rate of erosion, and decreases the threshold of the erosion process. This study enhances our understanding of how environmental stressors influence the long-term behavior of erosion protection materials. It provides engineers and environmental planners with insights for selecting and assessing materials for erosion protection, emphasizing the importance of considering environmental conditions in their design and application.","erosion; erodible; EFA; cyclic; clay; Boom Clay; kleirijperij","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:38af02e4-93b7-4784-b0a7-dbd0d0f65feb","http://resolver.tudelft.nl/uuid:38af02e4-93b7-4784-b0a7-dbd0d0f65feb","Energy Storage and Fluctuations in a Central-Spin Quantum Battery with Nearest-Neighbour Interactions","Kokkedee, Olivier (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Applied Sciences)","Blaauboer, M. (mentor); Dubbeldam, J.L.A. (mentor); Blanter, Y.M. (graduation committee); Thies, J. (graduation committee); Delft University of Technology (degree granting institution)","2024","In this thesis the stored energy and its fluctuations of a central spin battery with nearest-
neighbour interactions between the battery spins are investigated. Using analytical ex-
pressions, it is shown that for 2 battery spins and equal strength in the flip-flop interaction
g and nearest-neighbour interaction J, the fluctuations are minimal whenever the bat-
tery is maximally charged when taking at least four charge spins. Similarly, whenever
the formed envelopes of the energy have a zero, the fluctuations have a global maximum.
In the same limit, it could also be seen that an increase of the charge spins Nc and
spin-ups m, resulted in a higher global maximum of the stored energy. Furthermore for
2 battery spins, taking the limit J ≫ g results in a situation where the battery cannot
be charged at all, whereas taking the limit g ≫ J results in a central spin battery where
no nearest-neighbour interactions are present; its stored energy as a function of time is
a single cosine function, that is always able to reach its theoretical maximum.
Similar results were found for systems with more than 2 battery spins. Increasing J with
constant g resulted in a decrease of the global maximum of the energy, dropping from its
theoretical maximum to its minimum. Opposite behaviour could be seen when increasing
g with constant J. Whenever the global maximum of the energy crossed the line E = 0,
the fluctuations at the same moment in time formed a peak.","","en","bachelor thesis","","","","","","","","","","","","Applied Mathematics | Applied Physics","",""
"uuid:a2508ebc-adb5-41c3-a9de-a38fd98809f8","http://resolver.tudelft.nl/uuid:a2508ebc-adb5-41c3-a9de-a38fd98809f8","Semi-Supervised Integrated Learning of Mutational Signatures for Predicting DNA Repair Pathway Deficiencies","Tofacchi, Tommaso (TU Delft Electrical Engineering, Mathematics and Computer Science)","P. Gonçalves, Joana (mentor); Migut, M.A. (graduation committee); Höllt, T. (graduation committee); Goossens, A.C.H. (graduation committee); Delft University of Technology (degree granting institution)","2024","b>Motivation. DNA molecules mutate thousands of times every day. Some mutations are harmful to human cells, and may lead to the loss of function in important genes involved in DNA damage repair (DDR) mechanisms. Diseases such as tumors can exploit mutations in important, driver DDR genes to rapidly proliferate. Specific patterns of mutations (or signatures) are insightful indicators for the presence of DDR malfunctioning, which can be exploited to provide targeted treatment (e.g., by leveraging synthetic lethalities). Different methods have been developed to successfully extract relevant mutational signatures from the genomes of tumor patients. Most approaches are unsupervised and thus do not optimize toward distinguishing DDR deficiencies (DDRd). Supervised approaches achieve this, but rely on labeled in vitro data from tumor cell line genomes during training, due to the lack of DDRd ground truth for tumor patient genomes. Semi-supervised learning could bridge the gap and jointly exploit labeled cell line and unlabeled patient mutation profiles to generalize to patient tumors and provide more clinically relevant DDRd mutational signatures.
Results. We propose Pseudo-labeling Semi-Supervised NMF (PSS-NMF), a novel integrated signature extraction and label prediction method, which extends supervised non-negative matrix factorization (NMF) with the ability to incorporate unlabeled samples into the training via pseudo-labeling. Models learned using PSS-NMF were benchmarked on two different tasks, cancer type and DDRd prediction. PSS-NMF consistently improved prediction for patient tumors over the supervised NMF baseline for both tasks, learning signatures that better transferred to the patient tumor domain: the models achieved Macro F1 scores of 0.3842 and 0.1331 respectively for cancer type prediction, and 0.4928 vs 0.4704 for DDRd prediction. We further validated that PSS-NMF identified DDRd signatures were biologically relevant, by comparing them to known DDRd-related mutational signatures curated in COSMIC and investigating their exposures in patient tumor genomes.","","en","master thesis","","","","","","","","","","","","Computer Science | Artificial Intelligence","Master Thesis",""
"uuid:7660e4df-420c-4283-ab05-fd5ea6ec5a1b","http://resolver.tudelft.nl/uuid:7660e4df-420c-4283-ab05-fd5ea6ec5a1b","Development of experimental and analytical/modelling methods for the investigation of biomass pyrolysis and gasification in a novel indirect fluidized bed reactor","Tsekos, C. (TU Delft Large Scale Energy Storage)","de Jong, W. (promotor); Padding, J.T. (promotor); Delft University of Technology (degree granting institution)","2024","The modern world is faced with a multitude of environmental and socio-economic issues, stemming from the way that energy is used and converted. Climate change due to anthropogenic activities (use of fossil fuel resources and its associated CO2 equivalent emissions), has greatly affected humankind and nature in general, by leading to extreme weather phenomena and reducing the quality of life especially of people belonging to vulnerable communities. The unsustainable practices of the energy sector and the increased energy and materials needs of the public, have brought the situation to a point where immediate action is required to mitigate the effects of climate change. Furthermore, as became apparent by studying the impact of the COVID-19 pandemic and the Russo-Ukrainian war, the global energy market is heavily exposed to price and availability shocks that have a significant negative impact on the quality of life of people globally also in the very short term. Overall, the transition of the energy sector to a green and renewable alternative is essential and bioenergy constitutes a crucial piece of the puzzle of such a sustainable future....","","en","doctoral thesis","","978-94-6496-063-1","","","","","","","","","Large Scale Energy Storage","","",""
"uuid:158da0dc-e2a8-4c59-8af8-5b50b2b96c94","http://resolver.tudelft.nl/uuid:158da0dc-e2a8-4c59-8af8-5b50b2b96c94","Interplay of Structural and Light-induced Carrier Dynamics in Metal Halide Perovskites","Zhao, J. (TU Delft ChemE/Opto-electronic Materials)","Savenije, T.J. (promotor); Houtepen, A.J. (copromotor); Delft University of Technology (degree granting institution)","2024","As one of the fastest-growing renewable energy technologies, photovoltaics play an increasingly important role in the global energy transition. Over the past decade, metal halide perovskite solar cells (PSCs) have emerged as the most promising candidates for next-generation solar cells, with a certified power conversion efficiency of 26.1% for single-junction cells. Despite these significant advances in this performance, understanding the fundamental optoelectronic properties of various compositions is crucial to improve the efficiency and stability of the development of single-junction and multi-junction solar cells, including perovskite/silicon and all-perovskite tandem solar cells. In this thesis, we have investigated the generation, recombination, and extraction of photo-generated carriers in various metal halide perovskites (MHPs) in combination with selective transport layers (TLs) mainly using the time-resolved microwave conductivity (TRMC) technique. Moreover, structural properties were revealed using various techniques including XRD, XPS, and SEM. In addition, different deposition methods of perovskite thin films are studied with the aim of providing insights into the relationship between structure and optoelectronic properties.....","","en","doctoral thesis","","","","","","","","2024-03-19","","","ChemE/Opto-electronic Materials","","",""
"uuid:a565ae77-55f3-4e3c-b7a6-16b6dd9d510e","http://resolver.tudelft.nl/uuid:a565ae77-55f3-4e3c-b7a6-16b6dd9d510e","A design approach to achieve successful adoption of GoMedFlow in a hospital context","van Kampen, Demi (TU Delft Industrial Design Engineering)","Albayrak, A. (mentor); Vegt, N.J.H. (graduation committee); Kok, Petra (graduation committee); Delft University of Technology (degree granting institution)","2024","Digitalisation is becoming increasingly important in discharging the healthcare sector as our society ages, and long-term treatments of chronically ill patients are becoming necessary. However, adopting digital tools has not been smooth due to individual, organisational, and technical barriers. To overcome these barriers, a user-centred approach, co-creation, improved communication, and the involvement of the right stakeholders could help smooth the transition.
The GoMedFlow concept tool is a digital tool for healthcare professionals and organisational employees of the Reinier de Graaf Gasthuis that aims to improve the workflow of care processes and stimulate the use of digital tools. By creating a clear overview of care paths, improvements and digital tools can easily be noticed and implemented.
Using context mapping, stakeholders' wishes and needs were gathered at different levels of knowledge. A questionnaire revealed that stakeholders want to spend more time improving digitalisation, but not all have the time to contribute. Observations and conversations in the hospital uncovered insights into workflows and concerns, and generative sessions were held to dive even deeper and gather more insights. A design brief, including a design goal, was created to provide direction to the design process.
A co-creation session was held to involve stakeholders in the design process. Two groups provided ideas based on pre-created scenarios, and two different concept directions were created using Adobe XD. Before the concepts were created, a new corporate identity was created for GoMedFlow. Both concepts were tested during a care table and individually with stakeholders of care tables, and many insights were gathered. The second concept stood out more, but aspects of the first concept were still considered.
In order to finalise the concept of GoMedFlow, it is tested both during a care table and individually with stakeholders. The feedback and insights gathered from these tests are then combined to create the final design of the thesis. Additionally, a project journey is created to provide insights into the design choices made throughout the project. A roadmap is also developed to display the further steps that are required for a successful implementation of GoMedFlow. The thesis concludes with future research perspectives and a reflection.
To meet the goals of the Paris agreement,sustainable aviation fuels, such as hydrogen, need be adopted on a large scale within the coming decades. Hydrogen-assisted combustion of kerosene is investigated as an intermediate step in the transition towards sustainable aviation. This study addresses the gaps in the current understanding of hydrogen blending into kerosene with respect to chemical kinetics and emission of NOx, CO and un burnt hydrocarbons. A perfectly-stirred chemical reactor model is developed to study the fundamental effects of hydrogen blending into kerosene. Additionally, to focus on a more practical application the single-reactor model is extended to a chemical reactor network which represents a lab-scale lean premixed prevaporized combustor setup supporting multi-fuel combustion. Combustion characteristics and emission profiles are carefully studied for different hydrogen blending fractions using the developed models, as well as the reaction pathways in oxidation of hydrocarbons. Hydrogen blending is observed to increase the reactivity of kerosene, mainly due to increased availability of OH and H radicals, as well as O to a lesser extent. For 20% of kerosene mass substituted with H2, ignition delay time at 1200 K and 1 bard ecreases by 55%. Peak laminar flame speed increases by up to a factor of 2.2,while peak adiabatic flame temperature rises by 74 K. In rich burning conditions, H2 additions remove hydrocarbon reaction loops, which causes a strong decrease in un burnt hydrocarbon emissions and potentially soot. CO emissions can be greatly reduced from H2 additions at very lean conditions as overall burning rate is increased, which is corresponding to a reduction in lean extinction limit. This limit is reduced in the chemical reactor network combustor model by ∆φ=0.09 already for substitution of kerosene mass by 20%. For φ>0.6, dissociation of CO2 is enhanced from thermal effects and causes emission of CO to rise with hydrogen blending when normalized to carbon in fuel. This effect is reflected in the combustion efficiency, which is improved with H2 blending only for very lean conditions,φ<0.6. The reaction pathways of aromatics are modified with H2 addition,which results in a chemical inhibition of the mechanism responsible for thema jority of un burnt hydrocarbon emissions at very lean conditions. Furthermore,formation of NOx is increased via the thermal path since flame temperatures rise. The prompt NOx route becomes more efficient due to promotion of CH formation, while the N2O and NNH paths are enhanced from increased radical availability. Despite the increased emission of NOx at constant φ, blending H2under constant combustion power and combustor mass flow leads to decreasedflame temperatures and reduces total emissions of NOx, CO and unburnt hydrocarbons.","Chemical kinetics; Multi-fuel combustion; Hydrogen; Kerosene; CRN","en","master thesis","","","","","","","","2027-03-06","","","","Aerospace Engineering","",""
"uuid:30996490-72a9-48e4-aea1-558576466193","http://resolver.tudelft.nl/uuid:30996490-72a9-48e4-aea1-558576466193","Learning Vision-based Navigation Policies for Information Gathering with Quadcopters: A Deep Reinforcement Learning Approach","Vellekoop, Joris (TU Delft Mechanical, Maritime and Materials Engineering)","Alonso-Mora, J. (mentor); Lodel, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Deep reinforcement learning presents a compelling approach for the exploration of cluttered 3D environments, offering a balance between fast computation and effective vision-based navigation. Yet, the use of 3D navigation for learning-based information gathering remains largely unexplored. Navigation in 3D space poses the challenge of having an increased state space but also provides possibilities due to the agent's increased mobility, so it is an interesting direction for research. Furthermore, current approaches to target mapping with 3D navigation do not consider cluttered environments, failing to address obstacle avoidance and occlusion handling.
This research introduces a novel deep reinforcement learning policy for vision-based information gathering with quadcopters, enabling efficient exploration of cluttered 3D environments. The core challenge is learning a time-efficient and collision-free exploration strategy, for which the policy design and the training procedure have been successfully developed. We formulate a target-searching task, where the goal is to reduce the agent's uncertainty about the target state. To achieve this goal, our method combines vision-based reasoning by deep reinforcement learning and probabilistic target mapping with an information-theoretic rewarding scheme to obtain a policy that makes informed exploration decisions.
Experiments comparing our method with a privileged greedy baseline show that in all tested environments, our policy achieves a significant outperformance. The results from our ablation study further validate our policy design, as every ablation performed results in worse exploration performance. Generally, our policy shows intelligent behaviour by effectively navigating through rooms and around obstacles. However, improvements can still be made, since failure cases where the agent gets stuck, can sporadically occur. Still, overall, the findings prove the feasibility of learning a 3D navigation policy for effective target mapping with quadcopters.","Deep Reinforcement Learning; Target mapping; Exploration; vision-based navigation; Quadcopter","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:f94366c2-6461-4f71-84dd-b96a5f3c581e","http://resolver.tudelft.nl/uuid:f94366c2-6461-4f71-84dd-b96a5f3c581e","Circular social innovation and local government: Qualitatively assessing governance of circular citizen initiatives in Rotterdam","Koop, Kelvin (TU Delft Technology, Policy and Management)","Hoppe, T. (mentor); Quist, J.N. (graduation committee); Delft University of Technology (degree granting institution)","2024","There is a lack of academic attention towards the relationship between local governments and circular economy social innovations. While academic evidence suggests that local governments and policymakers can positively affect the success of social innovations, there is a lack of in-depth studies on how exactly they support social innovation. The main question of this study: How does the municipality of Rotterdam respond to the emergence of social innovation in circular economy, specifically to CCIs? This study aims to discover what circular economy social innovations entails in the municipality of Rotterdam, what policies and policy instruments are employed by the municipality of Rotterdam vis-à-vis circular citizen initiatives, how the interaction between the municipality of Rotterdam and circular citizen initiatives affects the transformative capacity of the latter, which bottlenecks and/or tensions are experienced with regards to the relationship between the municipality and circular citizens initiatives, and how the bottlenecks should be resolved according to circular citizen initiatives and the municipality of Rotterdam. The Local Climate Policy and Action framework, and transformative social innovation theory are utilised to develop semi-structured interviews. Said interviews are conducted among two civil servants who are involved with the citizen initiative, six participants of the citizen initiatives, and two academic experts. The results reveal four main bottlenecks: clashing institutional logics, tensions between civil servant and CCI participants, municipal and national regulations, clashing ideas of value-creation, and provision of accommodation. Analysis also revealed that the municipality does improve the transformative capacity of CCIs, albeit to a limited extent. Subsequently, these results discussed and explain using historic accepted practises that ensue from historic institutional logics. The paper continues by drawing conclusions regarding the discussed results and answering the research questions. Finally, recommendations for future research are made.","Transformative Social Innovation; Social innovation; Local governance; Citizen initiatives; circular economy; Qualitative analysis","en","master thesis","","","","","","","","2024-04-30","","","","Industrial Ecology","",""
"uuid:6427e548-9bc0-4aa6-afb6-a9319ca3693e","http://resolver.tudelft.nl/uuid:6427e548-9bc0-4aa6-afb6-a9319ca3693e","Optimizing the pump schedule of water distribution systems using a deep learning meta-model: To what extent can algorithm unrolling optimize the pump schedule of an urban water distribution system?","Mertzanis, Nick (TU Delft Civil Engineering & Geosciences)","Taormina, R. (mentor); Schleiss, M.A. (graduation committee); Garzón Díaz, J.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis investigates the integration of algorithm unrolling and genetic algorithms (GA) for optimizing pump scheduling in water distribution systems (WDS), a critical component for ensuring energy-efficient water delivery. In the context of modern civilization’s reliance on clean, affordable water for diverse uses, the operation of a WDS, particularly through energy-intensive pumps, presents significant challenges. Traditional optimization techniques often resort to hydraulic solvers like EPANET, which, while accurate, are computationally intensive for large-scale applications. Our methodology introduces a meta-model based on algorithm unrolling, building upon prior work and extending it to address pump scheduling with a multi-objective function focusing on both cost and energy efficiency. This approach significantly reduces the computational load, offering a faster alternative to EPANET while maintaining considerable accuracy. The meta-model demonstrated promising results in the Fossolo network, achieving comparable schedules 20 times faster than traditional methods. However, its applicability to more complex networks and its ability to capture detailed system behaviors are limited, highlighting the need for further enhancements in model stability and reproducibility. Despite these limitations, the study emphasizes the potential of meta-models as a complementary tool to traditional methods, especially in scenarios requiring rapid decision-making under computational constraints. This research contributes to the broader field of water utility management, offering insights into more sustainable and efficient operation strategies.","pump scheduling; optimization; meta-model; surrogate model; Deep Learning; Multi-Objective Constrained Optimisation; multi-objective optimization; Water Distribution Network; water distribution system","en","master thesis","","","","","","","","","","","","Water Management","",""
"uuid:435eaf14-15ac-4bc1-8f31-8bf89657c150","http://resolver.tudelft.nl/uuid:435eaf14-15ac-4bc1-8f31-8bf89657c150","Co-designing data-enabled information support for different chronic patient communities","Quijada Fernández, David (TU Delft Industrial Design Engineering)","Goossens, R.H.M. (graduation committee); Jung, Jiwon (mentor); Viswanathan, V. (mentor); Delft University of Technology (degree granting institution)","2024","This project aimed to facilitate information support between clinicians and patients that is dynamic to the milestones in their care path and can be incrementally adapted to different chronic diseases at ErasmusMC. The project strived to envision a foundational service that informs holistically about the doubts and concerns of patient communities throughout their care journey and can be progressively incorporated into clinicians’ workflows.
Research was done to find patterns between the online patient stories from community support forums and to identify value opportunities for intervention that align with the clinicians’ aspirations, motivations and needs. The research activities included:
Desk research of relevant literature (Chapter 2).
Contextual inquiry through a combination of human interpretation of patient experience data and computational analysis (Chapter 3).
Co-creation sessions to gather information about opportunities for improving information support from a data-enabled design perspective (Chapter 4).
The data categories derived from the contextual inquiry were used to map transactional services in the online patient support groups and ideate on new transactional services for the context of remote patient monitoring. The co-creation sessions inspired a service vision and a set of guiding principles that were used to conceptualise a service system for information support, which could improve the curation of patient support knowledge resources. It was decided to focus on information support among the different types of social support due to the co-exploration of the data categories with clinicians.
Ideation on a service system enabling dynamic and incremental information support resulted in three essential modules or features of the service system:
The first module, dynamic guidance, enables Erasmus MC to use recurrent milestones in the personalised care plan of patients to standardise the provision of information resources in templates. The patient community could progressively rate the usefulness and clarity of such resources to provide recommendations to the rest of the patient community.
The second module, PX data collection, offers the efficient collection of patients’ self-reported concerns and doubts for internal system and content improvements.
The third module, community appraisal, discusses how the development and moderation of conversations among peers could not only facilitate patients’ self-evaluation and emotional support but also the periodic research of shifting or uncovered areas of concerns, experiences and doubts among the patient community.
The interconnections between these modules have been conceptualised through a service blueprint, which was presented to ML and AI researchers to refine the supporting software processes.
These service features or modules could strategically be developed and implemented within existing eHealth applications within specific departments or in a foundational self-monitoring application for ErasmusMC that is shared by different departments (e.g., surgical oncology, pulmonology).
Outcomes
Thematic categorization of patient experience data has been established, which can be used to cluster results of unsupervised topic modelling for other patient communities and compare the results. A better understanding of guiding principles to design data-enabled services and systems, which facilitate information support for patient communities, has been achieved. A service system is proposed to standardise and incrementally fine-tune resources for different patient communities. Future developments are envisioned which encompass state-of-the-art machine learning techniques and interface/service design.
Problem background:
Furniture is a product category which causes a large environmental impact due to the materials they contain and consumers’ current replacement behaviour. In the Netherlands, over half of the large amount of disposed furniture pieces have not reaching the end of their lifespan (Koch & Vringer, 2023). Increasing repair and upgrading behaviour can extend the life of damaged or undesired furniture pieces and thereby reduce environmental impact.
Research & design goal:
Literature research, generative sessions, a survey and expert interviews were used to determine how a design intervention can most effectively contribute to the desired behaviour change. It was concluded that the design should support 18-35 aged, high income, high education consumers, living in the big cities, to ...
1. … make a plan with a desired outcome for ...
2. … together perform ...
... DIY repair and/or upgrade activities for furniture from the low/medium priced segment made from wood and/or textile and foam in 2024.
Design proposal:
The outcome of this master thesis is a design intervention named ‘Opknappers,’ a proposal for Intergamma (the umbrella organization of Karwei and Gamma). The proposal includes DIY cards and an exposition showcasing and explaining repair/upgrade possibilities in the physical shops. Additionally, a concept for the Opknappers app has been developed, which allows consumers to visualise upgrade options for their own furniture. Finally, a plan was made for using Intergamma’s websites and social media to support consumers in the DIY process. The final design was evaluated with customers and employees of Intergamma, and final improvements and recommendations were made.
Addressing this challenge, we propose in this work the concept of differentiated deployment, which allows online games to selectively manage and scale online-game systems with fine granularity in response to changes in available resources. We design Polka, a framework for online games which supports differentiated deployment. We then implement PolkaDOTS, an open-source proof of concept of the Polka framework built in an industry standard game development ecosystem.
We evaluate our approach using Dither, a custom-built experiment runner for large scale distributed experiments on online games. We use Dither to perform real-world experiments on a representative Minecraft-like Game, Opencraft 2, built on the PolkaDOTS stack, and analyze the impact of various differentiated deployment scenarios. From these experiments, we find that differentiated deployment can decrease performance variability of online-game servers, and decrease the response time experienced by players by up to 32%. Most importantly, we show that differentiated deployment enables novel deployment techniques, including switching from local rendering to cloud-based rendering (i.e., cloud gaming) at runtime.","opencraft; Distributed Systems; Online game; Scalability; Differentiated Deployment; Unity; Polka; Resource management","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:aa83b80b-bc9c-4c75-bde0-4a870c0996e2","http://resolver.tudelft.nl/uuid:aa83b80b-bc9c-4c75-bde0-4a870c0996e2","Optimizing hybrid-electric aircraft design and airline planning for efficient energy management and profitability through multidisciplinary coupling","Coelho Antunes, Sofia (TU Delft Aerospace Engineering)","Hoogreef, M.F.M. (mentor); Proesmans, P. (graduation committee); Santos, Bruno F. (graduation committee); Delft University of Technology (degree granting institution)","2024","","","en","master thesis","","","","","","","","2024-04-04","","","","Aerospace Engineering","",""
"uuid:962239e4-5c3d-4e94-a6e1-5577c96820e7","http://resolver.tudelft.nl/uuid:962239e4-5c3d-4e94-a6e1-5577c96820e7","Rotating Frame Relaxation Times for Off-Resonant MRI Pulses","Vermeulen, Mark (TU Delft Applied Sciences)","Coletti, C. (mentor); Weingärtner, S.D. (mentor); Vos, F.M. (graduation committee); Menzel, Miriam (graduation committee); Delft University of Technology (degree granting institution)","2024","Magnetic Resonance Imaging (MRI) is an important imaging modality, since it can create high-resolution cross-sectional images of the human body. In MRI scanners, the nuclear spin magnetization is excited using radio-frequency pulses. Images are created based on the time-evolution of this magnetization, which is characterized by relaxation times (T1,T2,T1ρ,…). These relaxation times change from tissue to tissue, and between healthy and diseased tissue.
Rotating frame (T1ρ) relaxation measurements are a promising technique for assessing slow molecular interactions in tissue. This has applications in articular cartilage imaging, and cardiac imaging without contrast agent injection. T1ρ measurements require continuous application of an electromagnetic excitation field. Variations of both the main magnetic field and the excitation field strength cause this excitation to be off-resonant. This in turn leads to contrast loss in the final images.
Adiabatic pulses, whose orientation changes slowly in time, are resistant to these off-resonance effects. Their effectiveness is dependent on their parameters, such as the peak sharpness β or the frequency modulation amplitude A. Conventional optimization techniques for these parameters neglect off-resonance effects.
In this project Redfield theory was used to create a pulse optimization algorithm that can take this off-resonance behaviour into account.
This graduation project explores how Conversational AI might be used in the context of setting up inter-organisational project briefs to help briefing writers improve their design briefings.
Explorative research on the challenges within creative corperate processes and GenAI opportunities clarified that design briefings are a major bottle neck within creative corporate processes
Recognizing this, it becomes evident that to effectively address this bottleneck, stakeholders need assistance in improving the quality of their design breifings prior to the meeting and without external help from the Creative Studio’s briefings reviewers.
This resulted in creating an conversational agent that enabled stakeholders to self-evaluate and improve the quality of their v1 briefings without external help before the first briefing meeting with the Creative Studio.
The final design was evaluated over the span of two sessions with an internal stakeholder of the case company and the Creative Strategist. In the first session, Jelly’s ability to assist the briefing writer was evaluated. In the subsequent session, the feedback comments of Jelly were compared to that of the Creative Strategist.
The results suggest that while Jelly has been effective in certain areas, such as providing detailed feedback that aligns with feedback standards of the briefing reviewers, it requires refinements in user interface language, feedback customisation, and context-specific content generation. The feedback from Jelly, when accurate, led to noticeable improvements in the quality of v1 briefings, aligning with the goals of enabling the stakeholder to self-evaluate their briefings independently.
The findings suggest that Jelly was found to be capable in offering valuable feedback that improved the quality of the briefing.
This thesis concludes with critical reflections to anticipate the future of GenAI in creative corperate processes. The first anticipation includes proposing a new relationship between GenAI and human creatives in the form of co-performance; where one fulfills a role, the other enhances its performance. The second anticipation states that large e-commerce organisation would have terms in their employee contracts that would consider personalised chatbots created by them as intellectual property of the company. In other words, in such organisations, personalised chatbots would likely be developed through a centralised approach.
Ultimately, the design contributes to the field of conversational AI design approaches in the context of corperate creative processes by providing a practical and reproducible example.
This project was set up in three main parts to identifying opportunities for sustainable interventions in colonoscopy procedures for the EMC gastroenterology department. Throughout the project, a human-centered design approach was maintained. Research was done in literature on sustainability in healthcare and environmental impact of endoscopy, empirical context research and material flow analysis (MFA) in the form of a waste audit.
Based on circular strategies Reduce and Recycle, the research outcomes were synthesized into an intervention that aligns to the EMC's policy statements for sustainability:
- reduce waste with 10%
- increase recycling with 20%
Waste audit data was used as an input for co-creating with endoscopy nurses, where the focus was put on retrieving plastics from GMW because of their significant contribution to total emissions when incinerated (López-Muñoz et al., 2023).
Ideation was done in co-creation sessions to solve the problem of integrating waste segregation inside the complex environment of a colonoscopy treatment room for current system boundaries.
Outcomes
While it is ideal to implement higher R-strategies for designing out waste early on in the process, waste cannot be ruled out completely. Therefore, implementing a waste segregation system in the endoscopy treatment room presents an opportunity to enhance waste management in EMC and align with sustainability goals.
The proposal is a demonstration rather than a product concept, to show small incremental changes within the current system boundaries can help achieve the EMC goals. The intervention was estimated to reduce the weight of incinerated GMW with at least 40% with segregation of plastic products, and additional 16% by disposing of absorbent products in TONTO. Additional research is needed to determine the true recyclability potential of the plastics.
With the foresight of the implementation of new products in the system and a circular model where materials of these products have to be kept in the loop, the endoscopy nurses will be equipped and trained to accomodate these changes, and maintain sustainable practices.
The following research question has been investigated: ‘’Which factors affect the implementation of Responsible Innovation dimensions in start-ups.’’","","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:8cf78935-a0d6-42d6-a1fc-9e25ce285fa9","http://resolver.tudelft.nl/uuid:8cf78935-a0d6-42d6-a1fc-9e25ce285fa9","Supporting non-expert users in modelling and understanding AI, an interactive CP approach: Bringing the power of advanced optimisation in employee scheduling to small and medium-sized organisations","Kropf, Kylian (TU Delft Electrical Engineering, Mathematics and Computer Science)","Yorke-Smith, N. (mentor); Bormans, R. (graduation committee); Tielman, M.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis proposes and develops an interface and model in which advanced optimisation for general employee scheduling is made available to non-experts in computer science or optimisation. The interface teaches, guides, configures, dynamically creates a constraint programming (CP) model, iteratively improves, decreases black box properties, increases trust in the outcome, and complies with relevant European Union Artificial Intelligence law. The objective of this study is to allow a wider range of organisations to take advantage of CP techniques, with the potential to greatly improve efficiency, reduce unfairness, meet company goals, and improve employee satisfaction.
Employees are assigned to personalised shifts based on the expected demands of departments within an organisation, these are set by the domain expert in the field of employee scheduling. Next, to tailor the model to the organisation’s needs, the domain expert is guided in setting both the restrictive assumptions and priorities of shift assignment. To optimise the generated optimal schedule, it is encouraged to create and compare multiple sets of configurations and subsequent schedules. Historical demand data, organisation structure, contract information, and employee preferences are included. Multiple visual design iterations have been made, after which a working interface has been developed and improved iteratively in conjunction with experts in the field. Validations with external domain experts from various industries and organisations have shown that the interface performed effectively in supporting the objectives. Further research can be done to improve the speed of solving, implement diversity of solutions, support for highly custom constraints based on natural language, or interface reusability for other optimisation problems.","combinatorial optimisation; multi objective optimisation; general personnel scheduling problem; domain expert systems; understandable AI; XAI","en","master thesis","","","","","","https://dyflexis.com Unspecified Dyflexis Employee Scheduling Software","","2024-12-31","","","","Computer Science","",""
"uuid:b7ff0b28-1bad-492d-a5c9-04db718518c9","http://resolver.tudelft.nl/uuid:b7ff0b28-1bad-492d-a5c9-04db718518c9","Integration of societal aspects in optimisation-based electricity system modelling","Crebas, Qin (TU Delft Electrical Engineering, Mathematics and Computer Science)","Bruninx, K. (mentor); Annema, J.A. (graduation committee); Wen, Xin (mentor); Trutnevyte, Evelina (graduation committee); Delft University of Technology (degree granting institution); University of Geneva (degree granting institution)","2024","Currently, restricting the utilisation of fossil fuels and thereby limiting global warming to remain below 2ºC stands as one of the most crucial challenges confronting us. The electricity sector is one of the main contributors of CO2 emissions, but it is changing in a rapid pace with a decarbonizing rate which is faster compared to all other fossil sectors. To facilitate the decarbonizing of the electricity sector, optimisation models can provide a valuable framework to gather information about the futuristics of the electricity market. As optimisation models can handle all sort of characteristics like demand and supply which should always be the same, certain policies, energy security, economic development and costs they play an important role in the transition toward more renewables and less fossil fuels. However, these optimisation models do not always present the right solution as societal factors are mostly missing, which can lead to misleading results.
In this paper we will specifically look at the D-EXPANSE optimisation model from the University of Geneva and incorporate two societal aspects. This will be implemented as a hindcasting exercise to examine whether or not it will improve the model compared to the regular model where no societal factors are implemented. This is applied on 31 European countries from 1990 until 2019. The societal aspects that are included in the D-EXPANSE model are public acceptance and heterogeneity of actors. Public acceptance is incorporated in the optimisation model with specifically limiting the CO2 emissions per country with the help of survey data provided from 2009 until 2023 in combination with the set global European emission targets. Heterogeneity of actors is implemented by specifically adjusting the weighted average cost of capital per technology per country per year.
The main results are that it is still unclear whether or not the implementation of societal factors improves the accuracy of the model as a whole. For the implementation of public acceptance 9 out of the 18 countries experience a positive change regarding the error compared to the model where no societal factors are implemented. For the implementation of heterogeneity of actors 13 out of the 26 countries experienced an improvement, and for the combination of both factors 12 out of the 22 countries showed improvements. With this in mind, it is not justifiable that the implementation of public acceptance and/or heterogeneity of actors in this way improves the model which is shown as a hindcasting exercise.
This thesis fails to provide evidence supporting the idea that the inclusion of societal factors enhances the capabilities of optimisation models. This contradicts existing literature, which emphasizes that the incorporation of societal factors is a primary reason why optimisation models struggle to accurately predict the future. One potential explanation for this discrepancy in our findings may lie in the specific methods used to implement actor heterogeneity and public acceptance in the model. For the public acceptance model, it is shown that there is still room for improvement with a different upper limit for the amount of CO2 emissions per country. This can increase accuracy up to 5 percentage points. Therefore, future research should focus on refining the implementation of societal factors, especially considering the accelerating pace of decarbonisation in the electricity sector. Factors such as supply and demand, electricity costs, and energy security remain crucial features that cannot be underestimated. Moreover, with the increasing integration of renewables into the electricity generation, societal factors will continue to exert a growing influence on the progress and implementation.
Background: Undetected Intellectual Disability (ID) can lead to chronic stress due to overestimation by society. Chronic stress can cause stress-related health issues, like hypertension, chronic fatigue and abdominal complaints. When a physician (General Practitioner (GP) or medical specialist) does not recognize that a patient has ID, the relation with stress may go unnoticed. In that case, the complaint is often treated as a purely somatic problem, while the underlying cause (overestimation due to unrecognized ID) remains untreated. This can increase healthcare consumption and impair the patient’s quality of life. While physicians with ID-expertise can recognize subtle signs of mild ID, physicians without extensive experience will easily overlook the ID. To improve medical care for patients with ID, we aim to improve ID detection among physicians. As it is not feasible to give all individual doctors an ‘ID-recognition training’, we study the possibility of using AI to improve ID detection. In the past years, we have been working on an ‘ID Alert’ (IDA) using ML. In previous phases of the IDA project, structured Electronic Health Record (EHR) data was used for the creation of an IDA. In addition, in the current study, we investigate the use of unstructured EHR data (clinical text).
Methods: We analyzed unstructured correspondence files of 200 ID-adults and 200 non-ID adults of Novicare, an organization that provides multidisciplinary care to clients with complex and chronic conditions in intra- and extramural settings. Structured clinical data was unavailable. Therefore, we used an automated method of text extraction, de-identification and two types of feature extraction (bag-of-words and clinical concept extraction). Features were compared between ID-adults and non-ID adults. Significant features that were unlikely to be intrinsically different between ID- and non-ID adults were excluded. The remaining significant features were used for the training and evaluation (10-fold stratified cross-validation) of two Gradient Boosting Classifiers.
Results: Most features differed significantly between ID- and non-ID adults due to confounders such as differences in age, type of care and the doctor’s word choice (which is inherent to the specialty and training of the doctor). Significant ‘unbiased’ features identified by both types of feature extraction methods are epilepsy, emotional disturbance (tension, arousal, agitation), visual or hearing problems and the presence of family members during consult. The developed ML models showed Areas Under the Curve (AUCs) of 0.98 and 0.89 for bag-of-words and clinical concepts, respectively.
Conclusion: This is the first study to investigate the use of unstructured correspondence files for developing an IDA. The developed models show a very high performance. Despite efforts to mitigate the effect of confounders, limitations may have influenced generalizability. Therefore, external validation of the proposed methods is necessary in future research.
It is challenging to understand formations riddled with fractures. From a computational perspective, the complex fracture networks typically demand a way finer unstructured grid. However, using such an unstructured grid is impractical for real-world applications due to their high computational load. Conversely, coarser grids paired with strategies such as homogenization could result in loss of crucial details. Heterogeneous properties of geological formations that span on large length sizes require the simulation strategies to be scalable, in order to be relevant.
This thesis proposes a novel approach named as multiscale extended finite element method (MS-XFEM) to tackle these challenges. The challenges related to discretization are resolved by applying the extended finite element method (XFEM) which allows for the use of structured grids. This simplified mesh, however, leads to an augmented matrix size due to extra degrees of freedom (DOFs) introduced by enrichments. A multiscale approach is therefore combined with XFEM. The computational process is operated on the larger yet sparser coarse grids and then the coarse scale mesh solutions are interpolated back to fine scale mesh. The novelty of this work is to involve the fractures into basis functions only, thus the coarse scale system is constructed based on a finite element method. More importantly, this construction of basis functions is fully algebraic and can be updated locally and adaptively for the simulation of propagating fractures.
This method has been implemented and tested to prove its efficiency and accuracy. All tests results prove the good qualities of solutions computed from MS-XFEM when compared to fine scale XFEM solutions. Basis functions are constructed successfully with the algebraic method. These tests reveal the potential of the MS-XFEM in simulating real-world subsurface fractured formations.","multiscale extended finite element method; geological fractured formation; fractures propagation; deformation of fractured formation","en","doctoral thesis","","978-94-6366-827-9","","","","","","","","","Applied Mechanics","","",""
"uuid:e81fe988-4347-4c4c-924e-2b9ef538bc49","http://resolver.tudelft.nl/uuid:e81fe988-4347-4c4c-924e-2b9ef538bc49","A Porous Iron Electrode for Electrochemical Ammonia Synthesis","Olsthoorn, Joost (TU Delft Electrical Engineering, Mathematics and Computer Science)","Mulder, F.M. (mentor); Jungbacker, M.P. (graduation committee); Delft University of Technology (degree granting institution)","2024","Ammonia is a precursor in fertilizer production and a potential carbon-free energy carrier, which is essential for the energy transition to more renewable energy sources. To that end, the current fossil fuel based method of industrial ammonia production through the Haber-Bosch process should be replaced by electrochemical ammonia synthesis. However, research into this topic faces several challenges, including a strong dinitrogen bond, competition from the hydrogen evolution reaction and low solubility of nitrogen in aqueous electrolytes, limiting the availability of nitrogen at the reaction sites on the electrode surface. In this study, in order to better understand these limitations to electrochemical nitrogen reduction to ammonia, a porous iron electrode is used in a cell design allowing both aqueous electrolyte and nitrogen gas access to the surface, which is successfully reduced electrochemically to serve as a nitrogen dissociation catalyst. Careful control of the applied potential limits the competition from the hydrogen evolution reaction. Nuclear magnetic resonance spectroscopy and ion chromatography measurements of the electrolyte were performed to check for possible contamination by nitrogen containing species. Small amounts of ammonia were measured using gas chromatography-mass spectroscopy on the gas output, but only with a high residence time of the nitrogen gas inside the cell. Since reduced iron surfaces are known to be good nitrogen dissociation catalysts, even at ambient temperature and pressure, the cause of the low ammonia production rate reported here is the abundant presence of water, which blocks nitrogen from the surface adsorption sites even when the catalytic surface is not submerged in the electrolyte. These results show that creating a surface with sufficient catalytic activity to break the dinitrogen bond is very well possible, but the main challenge is keeping the surface clean to prevent blocking of the reaction sites. This gives additional insight for future efforts in developing electrochemical ammonia synthesis methods.","ammonia; electrochemical nitrogen reduction reaction; energy storage","en","master thesis","","","","","","","","2026-03-01","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:117b9835-c012-4dca-bb1d-16c673896943","http://resolver.tudelft.nl/uuid:117b9835-c012-4dca-bb1d-16c673896943","Reliable Offine Policy Evaluation for Individualized Mechanical Ventilation","Volkers, Bas (TU Delft Electrical Engineering, Mathematics and Computer Science)","Krijthe, J.H. (mentor); Smit, J.M. (graduation committee); Reinders, M.J.T. (graduation committee); Oliehoek, F.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Individualizing mechanical ventilation treatment regimes remains a challenge in the intensive care unit (ICU). Reinforcement Learning (RL) offers the potential to improve patient outcomes and reduce mortality risk, by optimizing ventilation treatment regimes. We focus on the Offline RL setting, using Offline Policy Evaluation (OPE), specifically importance sampling (IS), to evaluate policies learned from observational data. Using a running example, we illustrate how a large difference between the learned policy and actual clinical behavior (behavior policy) limits the reliability of IS-based OPE. To assess this reliability, we use the Effective Sample Size (ESS) as a diagnostic. To achieve reliable evaluation, we apply policy shaping, by incorporating a divergence constraint in the policy learning objective, aiming to reduce the difference between the evaluation and behavior policy. We consider both a Kullback-Leibler (KL) divergence constraint and introduce a new constraint, the ESS divergence. Since effective OPE relies on an accurate estimate of the true behavior policy, we address how such an estimate is acquired. Various classifiers for estimating the behavior policy are systematically evaluated, focusing on both discrimination and calibration performance. Empirical results show the difficulty of learning policies that outperform existing clinical practices and generalize well to unseen patients. Although policy shaping improves the reliability of policy evaluations, no policies that consistently outperform clinician practice were found. The KL divergence constraint generalized better to unseen patients than the ESS divergence, which achieved large ESS without actually reducing the difference between the evaluation and behavior policy. We underscore the necessity of a cautious approach to applying RL in healthcare, and advocate that assessing OPE reliability and behavior policy calibration becomes standard practice, to ensure that only effective and reliable RL policies are considered for real-world clinical trials.","Reinforcement Learning; Offline policy evaluation; reliability; calibration; Offline Reinforcement Learning; Mechanical ventilation; effective sample size","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:199bf105-ce25-45d9-bc93-288d2e46ee2e","http://resolver.tudelft.nl/uuid:199bf105-ce25-45d9-bc93-288d2e46ee2e","Designing for the wellbeing of healthcare professionals: Using AI to reduce the administrative load of healthcare professionals & improve their job satisfaction","Verstappen, Gabi (TU Delft Industrial Design Engineering)","Goossens, R.H.M. (mentor); Jung, Jiwon (mentor); Hilling, Denise (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis, titled ""Designing for the Wellbeing of Healthcare Professionals: Using AI to Reduce the Administrative Load of Healthcare Professionals & Improve Their Job Satisfaction,"" explores the critical issue of healthcare professional wellbeing. It delves into the factors affecting their job satisfaction and the potential of artificial intelligence (AI) to alleviate administrative burdens. This research is part of a Master's graduation project in Strategic Product Design, specializing in Medisign, at the Faculty of Industrial Design Engineering, TU Delft.
Key Findings
The study identifies three major domains impacting the wellbeing of healthcare professionals: efficiency of practice, culture of wellness, and personal resilience. Efficiency of practice is influenced by workplace systems and processes, such as electronic medical records. Culture of wellness encompasses the values, attitudes, and behaviors within an organization that promote self-care and growth. Personal resilience refers to the skills, behaviors, and attitudes contributing to an individual's physical, emotional, and social wellbeing.
The research employs a desk research methodology, followed by semi-structured interviews with healthcare professionals, to explore these domains further. The findings highlight the importance of job demands and resources, including social support, skill utilization, autonomy, and job security, in influencing healthcare professionals' wellbeing.
Conclusions
Wellbeing in healthcare professionals is a complex interplay of job demands and resources, with significant implications for patient care quality and healthcare system vitality. The study underscores the need for a supportive work environment that fosters professional fulfillment and engagement. It also points to the potential of AI in reducing administrative burdens, thereby improving job satisfaction among healthcare professionals.
Recommendations
The thesis recommends focusing on enhancing the efficiency of practice, fostering a culture of wellness, and supporting personal resilience among healthcare professionals. It suggests that strategic product design, particularly through the implementation of AI, can play a crucial role in achieving these objectives.
Impact & future work
This thesis aims to make a valuable contribution to the healthcare sector by identifying ways to improve the industry from within. It hopes to inspire designers, policymakers, and healthcare professionals to prioritize the wellbeing of healthcare workers, recognizing their essential role in delivering high-quality patient care.
This study investigates this barrier to a successful digital transformation of the insurance industry. Following a literature review on innovations in this realm and technology acceptance, this thesis aims to identify factors influencing the behavioral intention to use technologies within this context....","business process automation; technology acceptance; Unified Theory of Acceptance and Use of Technology; Insurance; Emerging technologies","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:bbd11d77-f64a-4498-a0b8-16975f6e1e77","http://resolver.tudelft.nl/uuid:bbd11d77-f64a-4498-a0b8-16975f6e1e77","Computational design of patient-specific orthopedic implants: from micro-architected materials to shape-matching geometry","Garner, E. (TU Delft Biomaterials & Tissue Biomechanics)","Zadpoor, A.A. (promotor); Wu, J. (promotor); Delft University of Technology (degree granting institution)","2024","Background: Despite over a century’s worth of technical improvements, the longterm survivability associated with orthopedic implants continues to fall short. In contrast to earlier designs, implant failure is no longer caused by structural failure of the implant itself. Rather, it results from the implant’s long-term detrimental effects on the surrounding bone tissue. Over time, changes in mechanical loading conditions induce a reduction in bone density, increasing the risk of fracture, and destabilizing the bone-implant interface. The mechanisms which drive peri-prosthetic bone loss are complicated and inter-related. Add to this the unique morphological variations among patients, and an optimal one-size-fits-all solution seems unlikely.....
To alleviate the data movement bottleneck, contemporary research revisits a concept historically known as Computation-In-Memory (CIM) or, alternatively, Processing-In-Memory (PIM). At its core, CIM emphasizes positioning computational capabilities close to, or within, the memory units storing the data. This placement might be within memory chips, in memory controllers, amid caches, or embedded in the logic layers of 3D-stacked memories. As a computational model, architectures leveraging CIM (referred to as CIM architectures) stand to tackle the issue of data movement overhead inherent in the von-Neumann architecture by diminishing or outright eradicating the data movement between computational locales and data storage areas. Moreover, from a techno-logical perspective, emerging memory technologies, including memristive devices and circuits, show potential to replace traditional memory systems, addressing some of the challenges posed by CMOS-based designs.
Irrespective of the specific CIM architecture deployed to optimize performance or energy efficiency in modern applications, there are substantial practical challenges to address and ponder upon first. Both system designers and developers face these hurdles and design decisions, which are critical to surmount CIM’s widespread acceptance across various computational areas and application domains.
In this dissertation, our focus is twofold: (1) We delve into the acceleration and streamlined execution of various steps in two pivotal application realms: genomics and ML; and (2) We explore several emerging memory technologies alongside circuit and architectural strategies, that show promise in enhancing CIM designs, specifically tailored for modern applications.
Therefore, in this thesis, we identify and propose strategies and designs to ameliorate the constrained performance of key kernels in genomics and ML. Recognizing that applications within these realms consist of diverse functions or kernels, it is imperative for a designer to possess a thorough understanding of them. Each function/kernel can be characterized by distinct data and control flows, calling for varied features to be enabled in either a von-Neumann or a CIM architecture. To enhance the efficacy of each function/kernel, we first profile them individually and then within a larger context of their corresponding pipeline, followed by discerning the best avenues for their memory mapping in a CIM architecture. We then undertake a concurrent assessment of essential adjunct components alongside the memory array, commonly referred to as the peripheries. For a designer, proficiency in the applications executable on a CIM system leveraging emerging memory technologies is indispensable. Grasping the fundamental characteristics of CIM and having an overarching view of its scope becomes vital prior to its integration. We aim to aggregate critical application features, improvement opportunities, and design decisions and refine them to their core essence. Through this, we aspire to shed light on present design options and identify kernels demanding heightened attention. Such insights can be instrumental in revealing prospective directions, encompassing supported kernels along with their respective merits and trade-offs.
We exploit emerging technologies and architect state-of-the-art CIM designs that optimally serve the targeted kernels, keeping a holistic improvement perspective at the forefront. Delving into emerging (memory) technologies, such as memristive devices like PCM and STT-MRAM, is crucial. These devices provide a suite of advantages, including non-volatility, compactness, and a natural aptitude for conducting logical operations (for instance, the logical AND). Additionally, other emerging technologies, such as integrated photonics, have the potential to enhance the CIM paradigm further with their capacity for high-frequency and low-latency functions. Our ambition is to integrate multiple such technologies, harnessing their distinct attributes, to craft a CIM design that surpasses the SotA counterparts across key benchmarks, be it in execution speed or energy.
This thesis demonstrates that when CIM is fused with emerging (memory) technologies, there is a marked enhancement in the performance of several Genomics pipelines and Machine Learning applications. It is our aspiration and conviction that the evaluations, methodologies, and findings detailed in this dissertation will empower the broader community to comprehend and address contemporary and upcoming challenges that revolve around enhancing the performance and energy efficiency of modern applications through the integration of (re)emerging computing paradigms and technologies. Additionally, our work provides insights for adapting these technologies to novel applications, ensuring they deliver optimal benefits.","Computation-In-Memory; Processing-in-Memory; Bioinformatics; Computer Architecture; Hardware/Software Co-Design; Memristor","en","doctoral thesis","","978-94-6384-534-2","","","","","","","","","Computer Engineering","","",""
"uuid:c6e79ef9-49a0-41a0-8c77-36db46a4d34f","http://resolver.tudelft.nl/uuid:c6e79ef9-49a0-41a0-8c77-36db46a4d34f","Conformal Thinking for 3D Shaping of Bacterial Cellulose","Smit, Jason (TU Delft Industrial Design Engineering)","Karana, E. (mentor); Groutars, E.G. (graduation committee); Delft University of Technology (degree granting institution)","2024","A prototype for a production method is designed that can facilitate multiple geometries of statically grown bacterial cellulose for one mould. This production method, called CelluShaping, was developed after desktop research on bacterial cellulose. Here, topics regarding the material’s origin, cultural influences, its biological synthesis, material characteristics, applications and production, as well as topics regarding biodesign and conformality in design are discussed. From this research, a taxonomy is made, on which ideation on multiple principles are developed. After testing the most promising principles, a combination of two principles, where geometry is introduced through the growing bacterial cellulose sample from above the growth and from below. This principle, which is called CelluShaping, is elaborated upon and divided into its main components. From this understanding of the principle, a testing setup is designed and built. Also, a computational model, which aids in the hypothesizing of tests and is a first step in a tool to work with the production method is developed. With the testing setup and model, multiple tests are performed to test with multiple geometries and growing conditions. Finally, an overall conclusion, discussion, recommendation and reflection is given.","","en","master thesis","","","","","","","","2025-03-12","","","","Integrated Product Design","",""
"uuid:92721063-5738-4965-b1ae-4053141f0187","http://resolver.tudelft.nl/uuid:92721063-5738-4965-b1ae-4053141f0187","No Patient Left Behind: A Decision Framework for Addressing Representation Bias in Open Health Data: A Qualitative Study into the Use of Open Health Data","San José Sánchez, Samantha (TU Delft Technology, Policy and Management)","Zuiderwijk, AMG (mentor); Duran, J.M. (graduation committee); Figueroa, C.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","","","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:fe235ece-4c6a-4b8f-b56e-e1cd20582853","http://resolver.tudelft.nl/uuid:fe235ece-4c6a-4b8f-b56e-e1cd20582853","Design and integration of a microfluidic system into LiGalli’s MedRing platform","Spoerer Ruiz-Tagle, Sebastián (TU Delft Industrial Design Engineering)","Song, Y. (graduation committee); Paus-Buzink, S.N. (mentor); Heerema, O. (mentor); Delft University of Technology (degree granting institution)","2024","This project explores the integration of a microfluidic system within the MedRing device, aimed at enhancing women’s health monitoring by non-invasively tracking fertility-related biomarkers. The primary goal is to leverage MedRing’s capabilities to provide real-time, accurate health insights, thereby contributing to the advancement of personalised healthcare technologies.
The advent of wearable technologies has opened new avenues for personal health monitoring. This project focuses on the MedRing, a device designed for continuous health data collection, specifically targeting women’s reproductive health. By incorporating a microfluidic system, the project aims to extend the device’s functionality to include precise fertility monitoring, addressing the growing demand for non-invasive health management solutions.
The development process involved performing desktop research, interviews with experts, and analysing the current market. Then it moves on to designing and simulating the microfluidic system using computational fluid dynamics. Simulations were conducted to evaluate fluid flow, ensuring the system’s compatibility with the compact form factor of the MedRing.
A microfluidic system that can be assembled into the MedRing was designed. CFD simulations confirmed that the system achieves the objectives set in terms of laminar flow and fluid path, crucial for the system's correct operation. Design adjustments were made to optimise fluid path efficiency and ensure comprehensive sampling within the system’s reading chamber. The simulations demonstrated the system’s potential to accurately monitor, store, transport, and gather molecular samples within the constraints of the MedRing’s design.
While the project successfully demonstrated the theoretical feasibility of integrating a microfluidic system into the MedRing, the transition from simulation to real-world application necessitates further development. Future work should focus on prototyping and extensive testing to validate the system’s functionality in practical settings. Collaboration with biomedical experts will be essential to refine the system’s design, ensuring it meets both technical specifications and user needs. This project lays the groundwork for future innovations in wearable health technologies, emphasising the importance of integrating advanced diagnostic capabilities into everyday devices.","Microfluidics; Lab-on-a-chip; Aptamer; Fertility; Health monitoring; Femtech; Vaginal Ring","en","master thesis","","","","","","","","","","","","Integrated Product Design | Medisign","",""
"uuid:706dbcc5-99fb-47a8-8b02-46ff6df12e0f","http://resolver.tudelft.nl/uuid:706dbcc5-99fb-47a8-8b02-46ff6df12e0f","The assessment of flood mitigation measures applied in Cartagena de Indias: A case study approach about investigating types of flood mitigation measures in Cartagena de Indias","van de Wakker, Gerwin (TU Delft Civil Engineering & Geosciences)","Kok, M. (mentor); Schoups, G.H.W. (mentor); Onderwater, M.C. (mentor); Klooster, Jeroen (mentor); Delft University of Technology (degree granting institution)","2024","Urban areas of coastal cities are increasingly susceptible to the consequences of climate change. In particular, the threat of increasing floods due to sea level rise and heavier rainfall is growing. Cartagena de Indias in Colombia is such a coastal city, where flooding is a significant issue, with floods becoming more frequent in recent decades. Arcadis, together with the ConAgua consortium, is currently investigating and designing mitigation strategies for the city’s water-related issues. The thesis focuses on defining and quantifying the sources of urban flood problems and assessing the impact of potential mitigation measures for reducing these flooding problems.
The study consists of four parts:
1. Identifying the main causes of floods using a data analysis;
2. Quantifying these findings with a numerical D-Hydro model;
3. Investigating suitable kind of mitigation measures and quantifying the impact of the best feasible mitigation options;
4. Evaluating the investigated mitigation options based on several criteria with the help of a multicriteria analysis.
Parts 1 and 2 focus on understanding the system. Parts 3 and 4 of the study focus on finding the best option to reduce floods.
The data analysis allows the development of a system description identifying the main causes of flooding. The analysis reveals that the limited capacity of the drainage system, high topographic variations, and extreme rainfall are the main causes of flooding in Cartagena. Extreme rainfall flows quickly from steep upstream areas to milder slope lower-lying areas, particularly those at the edge of the Ciénaga de la Virgen. It is hypothesised that downstream water level plays a role in the accumulation of runoff water, thereby influencing the frequency and intensity of floods in the neighbourhoods at the southern edge of the Ciénaga de la Virgen, especially with a relative sea level increase of approximately half a meter factored in. This hypothesis is checked by quantifying the impact of different scenarios with a numerical model.
A numerical D-Hydro model is used to quantify the impact of different meteorological conditions and downstream water levels on floods. The model’s simulation results show that rainfall intensity is a more dominant factor in flood generation than downstream water levels. Even with a return period of two years, rainfall causes significant flooding of almost 25% in the study area. The model also indicates an increasing influence of tidal conditions due to relative sea level rise. Still, the increased influence is mainly visible in the borders of the Ciénaga de la Virgen with minimal residential impact. These conclusions highlight the need for mitigation efforts to focus primarily on improving the areas influenced by the rainfall, especially for short return period rainfall events.
Various flood mitigation measures are considered for the southern border of the Ciénaga de la Virgen to reduce floods caused by the dominant intense rainfall. Wetland creation and evaporation measures are ruled out due to the dominant influence of rainfall-induced floods and the inability to prevent floods caused by extreme rainfall events respectively. After investigating the scale required, considering feasibility, the three types of measures that are converted into mitigation options are:
• Mitigation Option 1: Increasing channel dimensions,
• Mitigation Option 2: Increasing infiltration,
• Mitigation Option 3: Constructing retention areas.
These mitigation options are assessed for their impact on reducing flooded areas and flood levels. The three mitigation options are evaluated to recommend the best-preferred mitigation design. This evaluation employs a Multi-Criteria Analysis (MCA)...","D-HYDRO 1D2D; Cartagena; drainage systems; mitigation measure; rainfall runoff modelling; D-FLOW FM","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:fef278fb-0f7f-4eaa-a837-2700215e3b33","http://resolver.tudelft.nl/uuid:fef278fb-0f7f-4eaa-a837-2700215e3b33","Real-time reconstruction of indoor ground surfaces in occluded environments filled with smoke based on point clouds obtained using LiDAR","Wiers, Christiaan (TU Delft Mechanical, Maritime and Materials Engineering)","Della Santina, C. (mentor); Kober, J. (graduation committee); Jovanova, J. (graduation committee); Heinecke, Robbert (graduation committee); Delft University of Technology (degree granting institution)","2024","With the current transition towards renewable and high-tech solutions, the world is becoming increasingly complex. Consequently, the challenges faced by firefighters also intensify. For that reason, firefighting robots are rising in popularity despite being far from perfect. An important area of improvement is the perception capabilities of those robots, given the fact that firefighting robots suffer from occluded camera views in environments filled with smoke. To overcome this challenge a LiDAR sensor may be used but experiments in this work show that even those point clouds are adversely affected by smoke. Consequently, this work presents a method for real-time reconstruction of ground surfaces in occluded environments filled with smoke. The developed method functions in ROS Noetic and merges segmented ground points, when available, with ground surfaces which are reconstructed based on information from segmented wall points. In this way, the method works even without the presence of ground points. To achieve this, a combination of established techniques from scientific literature, along with newly developed techniques were implemented. Doing so gives the robot’s operator an improved representation of the ground surface within environments filled with smoke. Ultimately the developed method may allow for autonomous navigation based on LiDAR data within environments filled with smoke. This research shows that a method consisting of techniques which tackle the independent sub-challenges arising from the use of LiDAR in indoor environments filled with smoke can effectively reconstruct the ground surfaces within those environments. Furthermore, the developed method has the potential to do so in a real-time manner.
Certain force-deflection behaviour can be purposefully designed by tailoring the energy storage over the range of motion. This is useful for passive exoskeletons where shell mechanisms are used to compensate the user's body weight and thereby decrease the fatigue accumulated during work. Other applications can be medical devices which often need specific kinetics while operating in a small environment. Shell mechanisms or shell flexures provide different kinetic behaviour than their flat counterparts: the wire flexure and leaf spring flexure. These properties of shell flexures can be leveraged to create more compact force generators.
Shell mechanism research is a relatively new field, with articles introducing novel designs with a specific behaviour in mind, such as constant force or moment generators. The state of the art presents what shell mechanisms are capable of. However, the state of the art provides little guidance in how to analyse and design shell mechanisms in general. The objective of this thesis is to propose tools for the analysis and design of compliant shell mechanisms or flexures and to develop understanding of this class of mechanisms. This thesis is divided into three parts.
Part I presents the eigenscrew decomposition as a tool to understand and design the kinetics of all compliant (shell) mechanisms. Part II discusses the properties of a buckled tape spring and a method to synthesise a wide array of force-deflection behaviour. In Part III, a novel category of shell mechanisms is introduced. A curved surface is patterned with a lattice, which is able to deform in the membrane of the shell. This is opposed to other shell mechanism that work primarily through the bending of the membrane.","","en","doctoral thesis","","978-94-6366-837-8","","","","","","","","","Mechatronic Systems Design","","",""
"uuid:0ea74101-a328-452a-a34e-e6e6e71fa786","http://resolver.tudelft.nl/uuid:0ea74101-a328-452a-a34e-e6e6e71fa786","A radical transition framework for the maritime innovator","Henderiks, Jurn (TU Delft Mechanical, Maritime and Materials Engineering)","Koning, Elwin (mentor); Pruyn, J.F.J. (graduation committee); Napoleone, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","The European Union has recently revealed a plan called ”Fit for 55.” The plan aims to reduce carbon dioxide emissions by 55% before 2030. It includes FuelEU Maritime, which will introduce new emission regulations for ships over 5000 gross tonnages. The regulations will require shipowners to reduce their carbon footprint. The European Union has decided not to wait for the International Maritime Organisation’s emission rules (IMO) and will enforce them for ships by 2024. By 2025, the rules will extend to offshore vessels with a gross tonnage of 400 or more and general cargo vessels carrying commercial goods between 400 and 5000 gross tonnages.
Efforts are being made to find a hydrogen carrier that closely resembles conventional oil-based products to comply with these regulations. All these fuels need to be produced with renewable energy sources, which have their efficiency losses. Renewable fuel production is only estimated to have a chemical efficiency of 50%.
Innovation in the shipping sector is necessary to reduce energy losses. The shipping sector fits the rules of rural society, where incremental innovations are preferred over radical changes. However, radical change is necessary to accomplish the energy transition in shipping. According to the DOI theory, innovators are the first group of adopters. Innovators are eager to try new ideas and have a cosmopolitan (global) network. These innovators will play a critical role in the energy transition in the shipping sector.
The study’s objective is to analyse if it is possible to influence a given adoption of the innovator. First, the research outlines the theoretical framework for the study. The literature search aims to determine a transition framework to answer the research sub-questions. The framework’s scope will be refined to the innovator group and the maritime sector. A case study will be conducted to test the defined framework, and factors outside the scope may be included if needed. The literature collection approach involves determining the philosophical framework before researching the sociological framework. The mainstream innovation and inclusive innovation frameworks have been identified from a philosophical perspective. The mainstream innovation framework focusing on radical and technological typology is more appropriate for the research study. Rogers’s sociological framework can be used to describe the adoption process. The Scopus search has been used to identify different theories, including spatial innovation frameworks, sectoral innovation systems (SIS), technological innovation systems (TIS), and path development. Finally, the study provides an overview of the innovation systems and their corresponding frameworks……","Maritime; Innovator; Radical; Innovation","en","master thesis","","","","","","","","","","","","Marine Technology | Maritime Operations and Management","","51.5591052,4.6256915"
"uuid:d9fc9a4e-54f7-4ffc-95c8-c02fc843daff","http://resolver.tudelft.nl/uuid:d9fc9a4e-54f7-4ffc-95c8-c02fc843daff","The Final Hurdles to Technical Implementation of Vehicle-to-Grid","van Eijk, Mark (TU Delft Technology, Policy and Management)","Annema, J.A. (mentor); Lukszo, Z. (graduation committee); van der Koogh, M.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","The automotive industry is transitioning to electric vehicles (EVs), creating a higher electricity demand. Concurrently, the utility sector is shifting to a renewable energy system. Vehicle-to-grid (V2G) technology allows EVs to both consume and deliver electricity to the grid, introducing a dynamic interaction. However, integrating EVs into the grid raises challenges related to grid safety, such as the risk of overloading. To address this, additional technical specifications are needed. The EV charging industry relies greatly on international standards. Therefore, market players seek clear guidelines for products enabling bidirectional power flows. However, technical requirements specific to V2G systems remain unspecified or divergent, creating obstacles for technology development and implementation by the industry. Harmonisation and standardisation of technical specifications are considered effective means for overcoming these challenges. However, existing literature lacks insights into the necessity and realisation of harmonisation. This study fills this gap by exploring the extent, reasons, and coordination efforts required for harmonisation of technical requirements specific to V2G. Particularly, this study investigates barriers stemming from the technical implementation of V2G and their impact on the adoption by key stakeholders.
An open-minded approach following the grounded theory principles identified primary obstacles in the technical implementation of V2G. The grounded theory approach included conducting semi-structured interviews with ten participants, which helped explore perspectives and needs of five key stakeholder groups. In addition, a comprehensive framework is consulted to provide a theoretical lens assisting the interpretation and analysis of the empirical results. Integrating the widely adopted Institutional Analysis & Development (IAD) framework and Multi-Level Perspective (MLP) aided in identifying and understanding the interplay between institutional arrangements, such as technical requirements and standards, and technology adoption. This novel approach has proven to be valuable in analysing the relationships between micro-level interactions (IAD) and macro-level influences (MLP).
This study has shown it is unclear to niche actors how to become ""V2G-ready"" due to a lack of clear guidelines, especially related to the charging standard (AC or DC), the communication standard between system operators (DSOs) and charge point operators (CPOs), grid connection codes, and who should be in control of discharging schedules. Requirements deficiency and disparities and the discussion on the control authority show constraining effects on the conditions for pilot projects. Realistic pilot conditions are shown to be essential for scaling V2G activities, and pilot projects are considered vital for exploring the possibilities of V2G technology. However, lacking conditions obstruct the development of definitive V2G configurations and designs necessary for large-scale diffusion. This study has shown two chicken-and-egg dilemmas play a significant role in the slow adoption of V2G. Niche actors are awaiting each other to continue their research and development activities. EV manufacturers demand V2G-compatible EV supply equipment (EVSE) to experiment with V2G technology, while EVSE manufacturers and CPOs await V2G-compatible EVs. Moreover, niche actors await definitive technical standards, while standardisation organisations and regulators are reliant on insights retrieved from practical experimentation to develop effective standards and regulations. These dynamics require a coordinated approach to empower and stabilise the development of V2G technology and enable widespread diffusion. Niche actors should be at the front of the developments, so active involvement with standardisation and requirement-setting is advised. Besides, collaborations between niche actors across Europe should be stimulated to prevent market fragmentation and segmentation, since these effects are detrimental to all V2G actors and the system in general. Therefore, the barriers identified pose a significant influence on pilot conditions, constraining experimentation, implementation, and the overall development of V2G technology.","V2G; Electric Vehicles; Grounded Theory; Institutional Analysis; Multi-Level Perspective","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:33651c36-9e08-480a-9d26-306b16453769","http://resolver.tudelft.nl/uuid:33651c36-9e08-480a-9d26-306b16453769","The European Ammonia Industry: Grey, Green or Gone?","van Muijen, Maarten (TU Delft Technology, Policy and Management)","Blok, K. (mentor); Roosenboom-Kwee, Z. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis explores sustainable and economically viable decarbonization pathways for the European ammonia industry. Through literature reviews, expert interviews, and detailed analyses, it addresses the industry's need to transition while maintaining competitiveness. Findings suggest that options like Autothermal Reforming (ATR) with Carbon Capture and Storage (CCS) are financially feasible, while biobased alternatives and electrolyzers face cost challenges but hold future potential. The study emphasizes the impact of the Carbon Border Adjustment Mechanism (CBAM) on global decarbonization efforts, reshaping trade dynamics. Policymakers must consider potential industry relocation and ensure food security amidst changing landscapes. Overall, this research provides a roadmap for sustainable decarbonization and underscores the importance of collaborative efforts for the European ammonia industry's future.","Ammonia; hydrogen; cost-effectiveness; Decarbonization; CBAM; Europe","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:41af2694-4f32-4249-ad45-da9215963963","http://resolver.tudelft.nl/uuid:41af2694-4f32-4249-ad45-da9215963963","Mitigating the gradual change in water partitioning at the Pannerdense Kop bifurcation","van den Brand, Siebe (TU Delft Civil Engineering & Geosciences)","Schielen, R.M.J. (mentor); Blom, A. (graduation committee); van Denderen, P. (graduation committee); Chowdhury, M. Kifayath (graduation committee); Kok, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","It is observed that the bed level development of the Pannerden Canal (PC) and the Waal changed since the peak flows of 1993, 1995 and 1998. The erosion rate of the Pannerden Canal decreased greatly just downstream of the bifurcation while the erosion rate of the Waal stayed more or less constant. This leads to an increasing depth of the Waal relative to the Pannerden Canal and therefore the Waal attracts more discharge. The model results from this study confirm that without anthropogenic interventions in the future, the Waal discharge fraction keeps increasing. The shift in discharge partitioning towards the Waal is an undesired development of the system as it causes problems for navigability, ecology, freshwater distribution and flood safety. Currently there is a lack of knowledge on how interventions can be used to mitigate the gradual change in discharge partitioning at the Pannerdense Kop (PK). This study aims at filling the knowledge gap by considering several interventions studying their effect on the discharge partitioning at the PK and on the Rhine branches surrounding the PK.
Firstly, an inventory of interventions which could possibly increase the Waal discharge fraction is made. The resulting selection of interventions is: A) a side channel from the Boven-Rijn towards the PC, B) fully opening the weirs in the NR-Lek, C) widening on the IJssel, D) directly steering the sediment partitioning at the PK and E) dredging in the PC and dumping in the Waal. These interventions are implemented in a 1D-morphological model of the Dutch Rhine branches.
It is found that the side channel from the Boven-Rijn to the PC (A) is not capable of significantly influencing the discharge partitioning at the PK. The backwater effects due to the water addition counteract the added discharge to the PC.
Furthermore, it is found that for the low Lobith discharges opening the weirs in the NR-Lek (B) can reduce the Waal discharge fraction below the initial value from the reference case for the whole simulated period of 60 years. The opening of the weirs does however lead to significant relative decrease in the IJssel discharge fraction which is unwanted regarding the freshwater supply of the IJsselmeer. For low Lobith discharges the widening on the IJssel (C) initially leads to a significant reduction in Waal discharge fraction of 2.4%. The effectivity reduces throughout the simulation because of aggradation along the widened reach. For high flows the opening of the weirs and the IJssel widening are less effective. The final relative Waal discharge fraction decrease is respectively 1.1% and 0.7%.
The results of the directly steering the sediment partitioning (D) are similar for high and low flows. The water level is not changed initially and therefore initially the discharge partitioning is not affected. Throughout the simulation the slope of the Waal adjusts to the increased sediment supply and the slope of the PC adjusts to the decreased sediment supply. For both flows the final relative decrease in Waal discharge fraction is 1.8%.
Dredging and dumping (E) shows similar effects on the bed level and discharge partitioning as steering the sediment partitioning at the PK. Dredging and dumping also does not alter the water level and the discharge partitioning initially. The relative bed level increase of the Waal is somewhat higher for the dredging and dumping simulation than for the simulation in which the sediment partitioning at the PK is steered. Therefore also the relative decrease in Waal discharge fraction is higher with 2.4% for the low Lobith flows and 2.2% for the high Lobith flows.
Currently the IRM program aims at stopping further skewing of the discharge partitioning of the PK. None of the interventions from this study is capable of realising this on its own. Therefore multiple river interventions will have to be combined to be able to reach the ambitions of IRM. The knowledge on the effect of the interventions on the discharge partitioning at the PK and the bed levels of the Dutch Rhine branches can be used as a basis for further study towards to combined effects of river interventions on the bed level development of the Dutch Rhine branches and the discharge partitioning at the PK.
Measurements confirm the significant influence of the ground coverage, mainly impacting the soil temperature in vertical (in-depth) direction. A detailed analysis reveals the quantitative effectiveness of the considered measures, indicating substantial cooling potential by modifying the ground coverage. Replacing concrete tiles with vegetation (in sandy soil) results in the most cooling effect of all analysed measures. White paint on concrete tiles emerges as particularly effective in reducing the soil temperature at the current depth in Rotterdam (0.7 m), and is considered an easily executable measure to prevent exceedances of the 25 °C threshold, mainly in case of urgency. In general, modifying the top layer as measure is considered feasible. This is because it avoids the need for excavation, in contrast to the alternative measures of relocation to a deeper level or in the shade. Additionally, the study quantifies soil temperature through simulations. A comparative analysis between simulations conducted by the soil temperature model and measurements facilitates an examination of the anticipated progression and the predicted effect of measures by the model, allowing for the formulation of recommendations to enhance the model.
As the results indicate that modifications to the ground coverage can significantly contribute to cooling the soil, this can mitigate potential threats to drinking water quality. The study advocates an integrated approach to decision-making, which includes collaboration between municipalities, drinking water companies, and research institutes. This cooperative effort is essential for identifying and implementing the most suitable and effective measures to safeguard high-quality drinking water, both now and in the future.","Drinking water temperature; Drinking water quality; Ground coverage modification; Soil temperature; Climate change; Urbanization; Field measurements; Soil temperature model","en","master thesis","","","","","","","","","","","","Water Management","",""
"uuid:b4c3e0b5-0431-4831-99af-21be86e10afa","http://resolver.tudelft.nl/uuid:b4c3e0b5-0431-4831-99af-21be86e10afa","A 24Gb/s PAM-4 Clock and Data Recovery Circuit With High Jitter Tolerance","Bas, Ivor (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Electronics)","Babaie, M. (mentor); Gurbaxani, R. (graduation committee); Sebastiano, F. (graduation committee); Delft University of Technology (degree granting institution)","2024","The escalating demand for higher data rates in modern communication networks are pushing more transmitters and receivers to use a modulation technique with more spectral efficiency, like pulse amplitude modulation 4-level (PAM-4).
On the receiver side, phase detection for PAM-4 has proven to be difficult with most receivers using phase detection for non return to zero (NRZ) data. This neglects most transitions and thus some phase information is lost. This results in low bandwidth and jitter tolerance, which is a problem in noisy communication systems where it will lead to a high bit error rate (BER).
This thesis explores an integrated PAM-4 clock and data recovery (CDR) circuit utilizing a novel PAM-4 bang bang phase detector (BBPD) considering all data transitions. A digital oscillator with variable gain is used in order to achieve high jitter tolerance as-well as low jitter generation. at 24Gb/s the CDR consumes 8mW and generates 487fs of jitter. and has a 1UI at 30MHz.","CDR; PAM-4; Jitter-Tolerance; BBPD","en","master thesis","","","","","","","","","","","","Electrical Engineering","",""
"uuid:a93d4da4-ce95-4932-9293-4adcc95a2966","http://resolver.tudelft.nl/uuid:a93d4da4-ce95-4932-9293-4adcc95a2966","Towards a neutrally stable compressible metamaterial","Zhu, Jeffrey (TU Delft Mechanical, Maritime and Materials Engineering)","Radaelli, G. (mentor); Herder, J.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","Neutrally stable metamaterials can maintain differ- ent shapes without any energy input, making it a key innovation in the quest for more energy-efficient technologies. Despite this intriguing property, the research in this area is scarce. This study proposes a method for achieving neutral stability in metama- terials. This method is validated with a novel unit cell design that utilizing two identical beam elements that are mirrored. Each element displays a constant force characteristic. By pre- tensioning these elements, we align their constant force regions, thereby inducing a state of neutral stability. Through finite element method (FEM) simulations and geometrical optimisation, the beam of this design is optimised to achieve the optimal constant force response. A prototype is made and a test setup is constructed to validate the accuracy of the simulations and the feasibility of the method for achieving neutral stability. Results indicate that while perfect neutral stability was not fully achieved, this method can be applied on other constant force mechanisms to create neutrally stable metamaterials.","Metamaterial; constant force; neutral stability","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Mechatronic System Design (MSD)","",""
"uuid:12135ffd-142c-4696-8ddf-3e41286eb042","http://resolver.tudelft.nl/uuid:12135ffd-142c-4696-8ddf-3e41286eb042","Functionally Graded 3D-Printed Scaffolds through Direct Ink Writing: Bridging Ceramics and Metals for Enhanced Multifunctionality","Zwart, Maarten (TU Delft Mechanical, Maritime and Materials Engineering)","Putra, N.E. (mentor); Mirzaali, Mohammad J. (mentor); Zadpoor, A.A. (mentor); Panahkhahi, S. (mentor); Taheri, P. (graduation committee); Delft University of Technology (degree granting institution)","2024","Over two million bone grafts are performed worldwide, each year. The preferred method is using autografts, but there are two important downsides. There is often insufficient tissue to harvest and the scar at the harvesting side is painfull for the patient. Therefore there exists a great need to improve synthetic grafts.
Traditionally, synthetic bone scaffolds are made from only one material, this can either be a (bioactive) ceramic or metal. The former has the benefit of promoting bone growth, but has insufficient mechanical properties. Metals on the other hand have no issue competing with bone in terms of mechanical properties, but they may not be biocompatible nor aid osteo-induction.
In this study direct ink writing was used to produce multimaterial Ti6Al4V and akermanite scaffolds. The goal was to combine the favourable mechanical properties of Ti6Al4V alloy with the osteo-inductive properties of akermanite. Composites of Ti6Al4V and akermanite were evaluated as well, but similar to akermanite ceramic on itself, their mechanical performance was deemed insufficient. Akermanite and Ti6Al4V was found to react and form titanium silicide and a calicum compound, presumed to be calcium oxide. A core shell scaffold was designed which uses a Ti6Al4V shell and an akermanite composite core in order to achieve both adequate mechanical and improved bioactive properties. This scaffold performed comparable to cortical bone in stiffness, and boasted superior strength.","Biomaterials; Bone; 3D Printing; Metal; Ceramic; Direct writing; Powder Metallurgy","en","master thesis","","","","","","","","2026-03-08","","","","Biomedical Engineering","",""
"uuid:f1db2b8a-49d3-4027-a04c-1e93fca0a397","http://resolver.tudelft.nl/uuid:f1db2b8a-49d3-4027-a04c-1e93fca0a397","Turbomachinery flow simulations with SU2: a numerical study","Vafi, Maurits (TU Delft Aerospace Engineering)","Pini, M. (mentor); Colonna, Piero (graduation committee); Pini, M. (graduation committee); Modesti, D. (graduation committee); Delft University of Technology (degree granting institution)","2024","Analysing and developing turbomachinery at off-design conditions requires the usage of robust and efficient Computational Fluid Dynamics (CFD) solvers. With the introduction of the computer, many advancements have been made in the field of numerical methods involving these flow problems. These numerical methods are used in order to solve these complex flow structures that are formed due to the interaction between the rotating machinery and the fluid. With the emergence of new design paradigms using computer-aided optimisation, novel solver methods are required which are able to deal with the increase in computational cost and the convergence difficulties following off-design conditions. One of the CFD solvers that is used for turbomachinery design is the open-source software SU2. SU2 is currently developed partially at the Delft University of Technology, where an increase in solver performance with respect to turbomachinery aerodynamics is greatly desired. The current work provides a numerical study of SU2's current performance with respect to turbomachinery analysis, as this is currently unknown.
The current performance of SU2 is to be analysed using steady RANS turbomachinery simulations. The research conducted by Xu et al. \cite{Xu2020} will be used as reference data in order to validate SU2's performance together with data obtained from the CFD solvers CFX and Numeca. The research conducted by Xu et al. resulted in the development of their NUTSCFD solver, which showed strong performance with respect to turbomachinery analysis. Four test cases are set up and used in order to analyse SU2. The test cases that are considered for the numerical study include: the NACA 0012 airfoil, the LS89 turbine cascade, the MTU centrifugal compressor and the 1.5 stage ETH turbine. The first three test cases are validated using the results obtained by the NUTSCFD solver, where the ETH turbine is validated using CFX and Numeca. Following these test cases, SU2's performance is analysed using the residual behaviour. Xu et al. dedicate their performance increase to be the result of the Newton-Krylov method that is implemented in their NUTSCFD solver. SU2 also includes a Newton-Krylov solver, but its performance with respect to turbomachinery is also unknown. A performance assessment with respect to SU2's Newton-Krylov method involving turbomachinery analysis is therefore conducted as well.
The results obtained using the NACA 0012 and LS89 test cases show a discrepancy in solver performance involving SU2. With respect to SU2's Newton-Krylov solver, the NACA 0012 test case shows a reduction in non-linear iterations where this is not found for the LS89 test case. Both results showed however a large difference in performance when compared to the NUTSCFD solver, where SU2's standard solver was also unable to match NUTSCFD. The results obtained following these test cases have led to the development of the MTU test case, where the MTU test case was to be used in order to provide a more accurate comparison between SU2 and NUTSCFD. Instead, SU2 was unable to run the MTU test case, where the solver showed stalling behaviour...","TURBOMACHINERY; NUMERICAL STUDY; SU2","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:072732ff-d91b-4c14-a903-94a35f430e08","http://resolver.tudelft.nl/uuid:072732ff-d91b-4c14-a903-94a35f430e08","Product-ProtoNet: A simple architecture for classifying supermarket products, using just a few example images","Dekker, Rick (TU Delft Mechanical, Maritime and Materials Engineering)","Wisse, M. (mentor); Caesar, Holger (graduation committee); Sabzevari, R. (graduation committee); Delft University of Technology (degree granting institution)","2024","Airlab, a collaboration between TU Delft and Ahold Delhaize, is developing Albert, a robot tailored to work in a complex supermarket environment. Key to Albert is a product detection and classification module that tells it what products to grasp and where they are located in a shelf. Albert’s existing YOLO‑based product detector a significant issue: Adding new products without re‑training the whole model is impossible. Especially in a dynamic supermarket environment with an ever‑changing stock, the latter is a major issue.
This problem will be the main focus of this paper and is addressed through few‑shot learning, which predicts similarity between query and target products. This simplifies adding new products to just supplying new target images. Few‑shot learning also requires significantly less data to train on. In supermarkets with 300.000 different products, requiring only a few images per product is a major advantage. For this reason, this paper aims to deploy a few‑shot model to classify products as either the target class or non‑target class for Albert’s picking task and defines the following research question: “What few‑shot classifier can identify products in a supermarket environment, is able to detect non‑target classes, and meets the requirements of deployment on a robotic platform like Albert best?“
This paper first analyses the potential of using TRIDENT and P>M>F, two state‑of‑the‑art few‑shot models, for deployment on Albert, and evaluates them on the requirements of this paper. P>M>F performs better on all requirements, which makes it the preferred model for Albert. However to work well, it still requires adjustments. Its inference time is still too high to work on Albert and it cannot classify query images as not the target product.
For this reason, this paper uses P>M>F’s two key ideas to construct Product‑ProtoNet, a new Albert‑suitable few‑shot model: 1) Using a good pre‑trained feature extractor; and 2) Comparing query images to a set of classes and matching only to the likeliest. P>M>F uses a ProtoNet model for classification that essentially does this; Like ProtoNet, Product‑ProtoNet constructs class prototypes from one or multiple examples of class images. Product‑ProtoNet then uses a sigmoid classifier to predict if query images have the same class as those prototypes. It compares query images to a set of similar class prototypes(helper prototypes) and classifies it as the likeliest. Product‑ProtoNet uses a ViT pre‑trained with DINO to extract image features. To bring down inference time, Product‑ProtoNet computes product prototypes before deployment.
With an accuracy of 99.1% on product classes seen during training and 99.8% on novel classes in a realistic supermarket setting, a low inference time of 2.89 ms and a memory usage lower than 4GB, Product‑ProtoNet is the only model that passes all requirements of this paper. When deployed on Albert Product‑ProtoNet successfully guides Albert to the right product in 97% of attempts. This makes Product‑ProtoNet the only few‑shot classifier that can identify products in a supermarket environment, is able to detect non‑target classes, and meets the requirements of deployment on a robotic platform like Albert.
To address this multifaceted issue, this dissertation delves into the complex nexus between climate shocks, regional economic dynamics, and societal responses. Central to this exploration is the creation of innovative simulation tools tailored to incorporate the autonomous adaptation strategies of various actors within a regional economic framework. This thesis stands at the forefront of a new wave of computational models that encompass risk and embed resilience into complex adaptive systems.
I commence by examining the current advancements and gaps in employing Agent-Based Models to unravel the dynamics of flood risk and adaptation assessments. In this exploration, I underscore the pivotal role of human actions in shaping risks and resilience within flood-prone urban settings.
Building on this foundation, I introduce the Climate-Economy Regional Agent-Based (CRAB) model. The CRAB model employs an evolutionary perspective to provide a comprehensive view of the balances struck between the driving forces of economic agglomeration and the counteracting pressures of climate hazards. It focuses on the decision-making of heterogeneous agents, representing households and firms, as they navigate the choice of relocation between safer inland regions and hazard-exposed coastal zones.
Venturing further, I enhance the CRAB model to embody autonomous household adaptation behaviors, drawing from empirical data. Here, I challenge the traditional reliance on rational agents in sustainability models, unveiling a notable adaptation deficit when juxtaposed against boundedly-rational choices gleaned from real-world surveys. This nuanced exploration uncovers how varied adaptive capacities can potentially accentuate inequality and impede resilience.
Subsequently, I include in the CRAB model a layered risk strategy that encompasses an array of climate change adaptation measures. This refined model, enriched by extensive behavioral and flood data, bridges existing gaps in the current understanding of feedback loops and cascading effects triggered by flood shocks within a socio-economic system of boundedly-rational agents.
In conclusion, this dissertation pioneers a unique trajectory in understanding societal responses to the specter of flooding, offering invaluable insights and frameworks for devising future climate-resilient strategies.","Agent-based models,; resilience; flood risk; agglomeration forces; survey; climate change adaptation; distributional impacts; path dependency","en","doctoral thesis","","978-90-361-0736-5","","","","","","","","","Policy Analysis","","",""
"uuid:facb282f-74a1-446d-bbc6-5ed294602ed2","http://resolver.tudelft.nl/uuid:facb282f-74a1-446d-bbc6-5ed294602ed2","Microstructural phenomena in pearlitic railway steels","Mattos Ferreira, V. (TU Delft Team Maria Santofimia Navarro)","Sietsma, J. (promotor); Petrov, R.H. (promotor); Delft University of Technology (degree granting institution)","2024","The railway industry constantly seeks advancements in train speed, axle load capacity, reliability, and rail longevity. Rails undergo complex and severe loading during operation due to wheel/rail contact, resulting in two main damage mechanisms: rolling contact fatigue (RCF) andwear. Furthermore, frictional heating during wheel/rail contact causes local temperature rise, leading to microstructural processes on the rail surface, known as white etching layer (WEL) and brown etching layer (BEL). This project aims to gain insight into the microstructural changes in rail steels, with a primary focus on understanding the origins of detrimental surface layers like WEL and BEL. By achieving this understanding, the lifespan of the rails can be extended and the maintenance frequency can be reduced, which has significant effects on the sustainability of the railway network as well as overall life cycle costs. Additionally, the project explores the microstructural characteristics of recently developed steel grades with enhanced resistance to rolling contact fatigue....","","en","doctoral thesis","","978-94-6483-777-3","","","","","","","","","Team Maria Santofimia Navarro","","",""
"uuid:24defb30-480c-4ce3-8130-0c66f02d1e00","http://resolver.tudelft.nl/uuid:24defb30-480c-4ce3-8130-0c66f02d1e00","Creation of a stand-alone milk steamer for home use","Piersma, Jeppe (TU Delft Industrial Design Engineering)","van Heur, R.J.H.G. (mentor); Verwaal, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Coffee, a beverage consumed by nearly every (young) adult on this planet. Black gold, the drink that keeps you awake and gets you through the day. Whatever the occasion, coffee is always there to accompany you. Coffee drinks consumed out of house are most often consumed with the addition of milk foam. The addition of milk fundamentally alters the sensory experience of coffee, it reduces bitterness, astringency and adds a degree of sweetness. Frothed milk especially enhances the texture and overall mouthfeel of the drink, contributing to a luxurious and novel sensory experience.
This luxurious feeling is especially present when consuming the drink, served with beautiful latte art, in a café. At home, this luxurious feeling is far from achieved by many people. Most often, the coffee drinks with milk are served with thick, airy and dull foam. An affordable product that can reproduce café quality milk from the comfort of your home currently not offered.
The need for such a product was identified during the master elective Build Your Start-up at the Delft University of Technology. This thesis aims to develop a working prototype of stand-alone milk steamer for coffee enthusiasts that allows them to create café quality milk foam at home. The results of this thesis will serve as a starting point for the further development to one day be used by many people around the globe.
During this project, the target group for such a product was formed and product wishes were identified through user research, market analysis and expert interviews. These wishes were combined to identify the required theoretical knowledge about milk foaming and foaming technologies for the further development of prototypes.
Fluid and thermodynamics models were created to aid the identification of promising technologies. Three heating technologies were identified that could showed promise for the creation of a stand-alone milk steamer. These technologies were evaluated using physical prototypes. Eventually, custom nozzles were designed to complete the prototypes. These prototypes were evaluated with experts and deemed very capable of reproducing café quality milk foam.
The final prototype that is revealed during the final presentation will serve as a prototype that serves multiple purposes. It serves as a technology demonstrator which can be further developed. Furthermore, it can be used as a tool to gather funds for the further development of the concept. All with the goal of eventually manufacturing and shipping a product to many customers.
The project approach was implemented using a context-driven design approach, consisting of Research & Analysis, Ideation, Conceptualisation and Evaluation. Literature research on the topic and its context is carried out, while further knowledge is gathered through contacts with sixteen Dutch and Kenyan medical professionals. In addition to individual interviews, two studies are conducted in the Dutch and Kenyan contexts. A six-week field trip to Kisumu, Kenya, during which ten medical professionals in three hospitals were visited, made it possible to ensure that the design truly fits its context. These medical professionals provided valuable input to the iterative design process and helped to shape the final concept design of the training system.
Further designing is enabled through prototyping, the use of decision-making methods and continuous iteration. This allowed new ideas to be generated, tested, and therefore new improvements to be made. Ultimately, new requirements could be identified, providing the opportunity to create even more valuable designs.
Future research should focus on further developing these designs, giving them an embodiment, and creating the possibility of actually implementing the training system in its intended context.
This study investigates user perceptions of individualized versus standard and random gait patterns, focusing on enjoyment, comfort, and naturalness. A predictive gait pattern model, incorporating individual data and walking speed, was developed and tested with human participants using a grounded robotic lower limb device. Participants compared the three gait pattern types and provided subjective feedback through a questionnaire.
Findings indicate no significant preference for any gait pattern in terms of enjoyment, comfort, and naturalness, except for physical strain where the predicted pattern caused significantly more strain than the standard. The analysis also revealed that longer engagement with the device led to increased comfort and naturalness, suggesting an adaptation effect. A general tendency towards preferring the standard pattern was noted, though further research is necessary to determine whether a larger sample size reveals significant differences. Additionally, the perception of different gait patterns and their effect on the rehabilitation outcome should be explored with stroke patients.","Robotic gait rehabilitation; Reference joint trajectories; Gait generation; Human factor experiment; Comfort","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:c0e89fe5-bc26-4f68-a965-5017ab58bc9c","http://resolver.tudelft.nl/uuid:c0e89fe5-bc26-4f68-a965-5017ab58bc9c","First steps into the calibration chamber pile tests with glauconitic sands: On the behaviour of the sand fraction from glauconitic sand of the Kattendijk formation in Antwerp, Belgium","Rodriguez Piedrabuena, Alba (TU Delft Civil Engineering & Geosciences; TU Delft Geo-engineering)","Gavin, Kenneth (mentor); Kementzetzidis, E. (graduation committee); Mento, M. (graduation committee); van Wijk, Jort (mentor); Delft University of Technology (degree granting institution)","2024","The Global Wind Energy Council (GWEC) forecasts an accelerated increase in wind installations as a result of the aggressive climate change and green energy objectives set by the majority of countries. As a consequence, new regions worldwide that were previously thought to be unsuitable for the construction of offshore wind farms due to the soil characteristics are planned to be explored. This is the case of glauconite sands, which include glauconite pellets that are very susceptible to crushing. The crushing transforms the coarse-grained sand into a fine-grained soil, changing the geotechnical characteristics of the soil. This poses particular geotechnical challenges, since the soil-structure interaction between the pile being driven and the sand changes, the side friction increases with depth and the prediction of blow counts in drivability analyses is underpredicted. In addition to this, the glauconitic sand influences the response in cone penetration tests (CPTs), characterised by high cone tip resistance (qc) and sleeve frictions (fs), leading to high friction ratios (Rf) and resulting in misleading soil classifications. IQIP, as a company specialised in installation and foundation projects internationally that provides innovative and high-quality equipment and solutions for construction projects related to Offshore Wind industry, is interested in better understanding the mechanical behaviour of glauconite sand during pile installation due to the risks posed by this sand, e.g. premature pile installation refusal. In order to understand this soil that poses geotechnical challenges, laboratory test programs should be designed in order to capture the soil behaviour and physical modelling is a cost effective and valuable tool. This research aims to obtain detailed information on the soil response of glauconitic sand in saturated conditions during pile installation with a new sample preparation method for glauconitic sand containing fines. It will investigate the feasibility of cone penetration testing, cyclic loading, pile driving, as well as the analysis of the shear band and grain crushing around the instrumentation penetrated in the sample in a calibration chamber (CC). Based on the results from the three performed tests it could be concluded that the preparation method led to a good procedure to prepare repeatable and homogeneous samples under fully saturated conditions, as well to a representative response to pile penetration. With this, it is possible to perform further research on the sand fraction of glauconitic sands using the same sample preparation method and testing equipment.","glauconite; calibration chamber tests; pile installation; offshore","en","master thesis","","","","","","","","","","","","Geo-Engineering","",""
"uuid:6de6f1c1-1b97-4e44-a277-5a3f14f1c662","http://resolver.tudelft.nl/uuid:6de6f1c1-1b97-4e44-a277-5a3f14f1c662","2 DoF surgical training eye phantom for cataract surgery in a low-cost setting","Shenoy, Rajath (TU Delft Mechanical, Maritime and Materials Engineering)","Dankelman, J. (mentor); Oosting, R.M. (mentor); Delft University of Technology (degree granting institution)","2024","The human eye is a very delicate yet highly intricate organ, and treatments such as cataract surgery call for meticulous precision. Ophthalmologists hone their skills over years of practice, which they initially acquired during their studies in medical schools. Basic skills such as globe fixation and capsulorhexis training have a very steep learning curve as they are fundamental, albeit very challenging from the get-go. There is a lack of training simulators that can combine both surgical techniques as effectively and economically as animal eye setups. In this respect, the present research work aims at designing a cataract surgery eye phantom for capsulorhexis and globe fixation, which can replicate the movement of the eyeball in the orbit coupled with the inherent passive stiffness. The project culminates in the design of a 2-degree-of-freedom anterior human eye phantom with anatomically similar features of the human eye needed for training the aforementioned surgical steps. A significant part of the prototype structure is 3D printed using Draft resin V2 on the Formlabs Form 3+ printer to create minute yet almost anatomically impeccable components. Mechanical analyses were performed to tune the passive stiffness of the compliant mechanisms, and materials such as PlatSil Gel-00, hydrogel, and eggshell membrane were chosen and utilized to replicate the interactions between the tools and various tissues in the human eye. Clinical evaluations were conducted by a surgeon performing capsulorhexis on the prototype in a wet lab environment and several validation tests by an academic trainer for the suitability and practicality of the prototype. In that context, the present research serves as the first step toward creating innovative designs for training phantoms in the field of eye surgery.","eye phantom; Ophthalmology; capsulorhexis; training; 3D printing; Compliant Mechanism; Cataract surgery","en","master thesis","","","","","","","","","","","","Mechanical Engineering | BioMechanical Design Engineering","",""
"uuid:bdefeac4-4bae-46f6-9f9a-6ae36b9da988","http://resolver.tudelft.nl/uuid:bdefeac4-4bae-46f6-9f9a-6ae36b9da988","Towards Circular Batteries: Investigating Particle-Size Based Separation of Active Materials from spent Li-ion batteries","van Rooijen, Abel (TU Delft Mechanical, Maritime and Materials Engineering)","Botto, L. (mentor); Delft University of Technology (degree granting institution)","2024","With the enormous growth of portable electronics and the market expansion of electric vehicles, the demand for lithium-ion batteries is increasing enormously. To meet this demand, efficient recovery of battery components becomes crucial. Graphite, the material of choice for lithium-ion battery anodes, faces significant supply risks as current recycling technologies primarily focus on recovering economically valuable metal components like cobalt and nickel. Therefore, the effective separation of graphite from lithium-ion batteries is essential for recycling and reusing anode materials. The key to the direct recycling of graphite is the separation of the finest material fractions of Li-ion batteries: the anode and cathode. This work tests a circular battery manufacturing principle based on the idea that the an ode and cathode could be designed to have a difference in particle size to allow easy separation by centrifugation.
We analysed the particle sizes of anode and cathode material obtained from a spent Li-ion battery. A shift in particle size distributions is observed by grinding the materials, significantly reducing the particle sizes. We calculated the velocity distributions using Stokes’ formula for the settling velocity of spherical particles in dilute suspensions from these size distributions. Combining the velocity distributions for the anode andcathode showed the overlap of the velocities. A combination of milled and unmilled material shows the smallest overlap between the velocity distributions and, therefore, the largest difference in sedimentation velocity and the highest theoretical separation.
We measured the sedimentation of anode and cathode particles in water optically using a light source. A camera tracks the moving front of the dilute suspensions over time. Experiments of different milled samples for various concentrations show insights into the anode and cathode sedimentation behaviour. Results show that increasing concentration significantly reduces sedimentation velocities for the anode material. Theseresults deviate from what would be expected from the hindered settling of dilute suspension. A significant velocity reduction is measured for the milled anode and cathode, therefore showing the potential for separation if the materials have a marked difference in size.
In this thesis, a novel method is developed for characterising the sediment structure of the mixed active materials. By freezing sedimented suspensions, sample layers are horizontally cut off to look for the spreading of the different material components through the sediment. A combination of characterisation methods offers information about the anode and cathode fractions through the sediment layers. Significant differences between the sediment’s top and bottom layers regarding morphology, elemental components and thermal stability are observed.
The results show the potential for circular batteries in the future, where centrifugation can play a vital role in separating the electrode materials if they have a marked size difference.","","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:59a8a498-fc17-467d-ab9f-bb2433101f67","http://resolver.tudelft.nl/uuid:59a8a498-fc17-467d-ab9f-bb2433101f67","Aerostructural Assessment Approach of a Transonic Morphing Wing in 3DExperience","Middendorp, Lizzy (TU Delft Aerospace Engineering)","De Breuker, R. (mentor); Peeters, D.M.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","The implementation of morphing wings technology has the potential to significantly improve aircraft performance. However, due to the complex interplay between aerodynamics and structural integrity, it requires an aerostructural analysis. 3DExperience by Dassault Systèmes is a Computer-Aided Design (CAD) - based software with integrated structural and aerodynamic analysis tools. This software was employed to establish a methodology for conducting one-way aerostructural analysis of morphing trailing edge wings on a transonic transport aircraft. The methodology highlights the benefits of CAD-based modelling and the coupling between the aerodynamic and structural models. Nevertheless, the aerodynamic analysis results were affected by a node limit and the meshing options. Finally, a high-lift and an aerodynamically efficient test case were utilised to compare the impact of the trailing edge morphing to that of an unmorphed wing.","CFD; FEA Simulation; aeroelastic","en","master thesis","","","","","","","","","","","","Aerospace Engineering | Flight Performance and Propulsion","",""
"uuid:53f55ed8-2cf3-4625-9071-28a3185029ee","http://resolver.tudelft.nl/uuid:53f55ed8-2cf3-4625-9071-28a3185029ee","Enhancement of Aeroacoustic Testing: Applied to closed-section wind tunnels","Hinssen, Yara (TU Delft Aerospace Engineering)","Simons, D.G. (mentor); Merino Martinez, R. (mentor); Delft University of Technology (degree granting institution)","2024","Aeroacoustic testing in wind tunnels is crucial for understanding and mitigating the noise generation mechanisms in several devices while maintaining satisfactory aerodynamic performance in the conceptual design stage. However, current measurements in closed-section wind tunnels face challenges in terms of installation, due to the effect of the boundary layer of the wind tunnel walls, and accuracy. To address these issues, the proposed methodology integrates advanced signal processing techniques and cost-effective and limited alterations in a closed-section wind tunnel. Different configurations, such as a perforated panel, a perforated panel with melamine foam rings, and the addition of melamine foam panels behind the array and inside the wind tunnel combined with the use of a microphone array consisting of 88 microphones, recessed behind an acoustically transparent stainless steel mesh, has led to significant improvements in signal-to-noise ratio and measurement accuracy compared to the baseline aeroacoustic testing. In general, this setup enables the identification of noise sources with a signal-to-noise ratio of at least -10 dB. Additionally, the utilisation of advanced beamforming techniques (CLEAN-SC and DAMAS) in post-processing yields clearer outcomes. Finally, the effectiveness of the set-up was evaluated, resulting in an approximate 15 dB improvement in peak prominence of the flow-induced noise source due to the higher number of microphones and beamforming.
This dissertation addresses this gap in four aspects. First, a low-fidelity noise model based on state-of-the-art literature is developed, allowing fast, acceptable, and accurate predictions for preliminary design stages of the primary noise sources on an urban VAWT. Then, a wind speed estimator and tip-speed ratio (WSE-TSR) tracking controller is designed to maximise the power production of an urban VAWT in turbulent wind conditions. This WSE-TSR tracking controller turned out to be an ill-posed problem, impacting the turbine and controller performance in the presence of model uncertainty. Follows the presentation of an approach that combines frequency-domain analysis and multi-objective optimisation, demonstrating its effectiveness in assessing and calibrating torque control strategies, thereby contradicting earlier assumptions and establishing new perspectives on performance optimisation for real-world wind turbines. Based on these collective findings, a decision-making framework is derived, capable of striking a balance between VAWT performance and noise acceptance, allowing for the first time to consider psychoacoustic annoyance as a metric.
In summary, this thesis contributes significantly to advancing the understanding of the complex dynamics of VAWTs, specifically focusing on human acoustic perception nearby, laying the groundwork for the successful integration of VAWTs into urban landscapes.","vertical-axis wind turbines; aerodynamics; aeroacoustics; control; optimisation; noise","en","doctoral thesis","","978-94-6496-046-4","","","","","","","","","Wind Energy","","",""
"uuid:3bd93d0f-6ce7-4285-83e8-9efecf553a7d","http://resolver.tudelft.nl/uuid:3bd93d0f-6ce7-4285-83e8-9efecf553a7d","Enhancing data center efficiency through eco-mode integration: Providing a framework for data center parameter analysis","Kerkhof, Franck (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Network Architectures and Services; Koninklijke KPN)","Smeitink, E. (mentor); Al-Ars, Z. (graduation committee); van Boven, E.F.M. (graduation committee); Cox, J.S. (graduation committee); Tuinhof, D.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","The demand for computational resources is increasing exponentially due to an increasing amount of digital services. Cloud computing is becoming the standard for enterprises to provide these resources. This resulted in hyperscalers which consist of a large number of servers. Data centers consume more than 1% of the world’s electrical energy. Therefore, many techniques are developed that both help to fulfil the needs of digital services and reduce the energy consumption of data center services. Modern-day servers can switch between different operating states which are often integrated in a power configuration mode of servers known as eco-mode. One of these techniques throttles the clock frequency of a central processing unit (CPU) which enables the possibility to lower the power needed for that CPU. This technique is known as dynamic frequency and voltage scaling (DFVS) and the states it switches between are known as performance states (P-states). A different technique that is integrated with eco-mode is the ability to switch between different idle states of the CPU. These states define whether certain caches of the CPU are flushed or not to conserve energy. These states are known as core states (C-states). A different approach that is focused on conserving energy is virtualisation within data centers. Virtualisation enables one physical server to host multiple virtual instances of servers (virtual machines). This reduces resource wastage and energy consumption of a data center. However, this creates the need for a strategic placement that ensures that the demands of the virtual machines are met and that minimises energy consumption and resource wastage. This thesis analyses four of these techniques: the best fit decreasing (BFD) algorithm, the integer linear programming (ILP) algorithm, the particle swarm optimisation (PSO) algorithm and the genetic algorithm (GA). This thesis provides a framework that uses a holistic approach to provide insights into the effects of using eco-mode of servers within the dynamics of virtual machine placement in data centers. This framework serves as a first step in parameterising the dynamics of a data center regarding its energy consumption and performance. The results show a potential energy reduction of up to approximately 20% with negligible impact on a data center’s performance. This result occurs when applying the best fit decreasing algorithm and having a server with an energy-efficient eco-mode. However, this thesis does not cover all parameters that play a role in the data center’s performance and energy consumption, so more research on this area is recommended.","Data center; eco-mode; Energy-Efficiency","en","master thesis","","","","","","","","","","","","Electrical Engineering","",""
"uuid:1050486b-da63-48a7-97f2-bf9bbadcbd1b","http://resolver.tudelft.nl/uuid:1050486b-da63-48a7-97f2-bf9bbadcbd1b","Reliability assessment of flexible dolphins: Reducing uncertainty in the design approach of flexible dolphins","Bechan, Rushil (TU Delft Civil Engineering & Geosciences)","Voorendt, M.Z. (mentor); Heeres, O.M. (mentor); van Gelder, P.H.A.J.M. (graduation committee); Roubos, A.A. (graduation committee); de Gijt, J.G. (mentor); Delft University of Technology (degree granting institution)","2024","The abstract outlines a study focusing on improving the design approach for flexible dolphins, vital marine structures used for vessel berthing and mooring. Current design methodologies, particularly those outlined in the CROW C1005 handbook (2018), are questioned due to potential conservatism stemming from insufficiently calibrated partial factors. The study advocates for reliability-based assessments to address these concerns, which consider uncertainties inherent in dolphin design and quantify failure probabilities over their lifespan. The investigation identifies critical failure modes and determines main pile dimensions based on these modes, utilizing the API PY-curves for rapid computation in the design process. Probabilistic assessments, employing Directional Sampling, reveal the significance of berthing load in structural safety and identify soil parameters as dominant variables affecting fixity failure mode. Navigation conditions, ship arrival rates, and variation in ship sizes also influence partial factors, with recommendations provided for adjustments based on different conditions. The study suggests load testing to reduce uncertainties and increase reliability, exemplified by a Bayesian update from Calandkanaal full-scale load tests. Overall, reliability-based assessments yield insights into managing uncertainties in dolphin design, potentially reducing material usage by up to 20% while meeting safety requirements, and offering the potential to decrease failure probabilities tenfold when combined with test loading.","structural reliability; Bayesian updating; reliability updating; probabilistic assessment; Dolphin; probability of failure; Partial factors","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:11af06dd-e28b-41d0-ba53-85b437af0cbc","http://resolver.tudelft.nl/uuid:11af06dd-e28b-41d0-ba53-85b437af0cbc","Current-Based Impedance Control for Mobile Manipulators Without Force/Torque Sensors","de Wolde, Jelmer (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Cognitive Robotics)","Alonso-Mora, J. (mentor); Knödler, L. (mentor); Delft University of Technology (degree granting institution)","2024","Mobile manipulators, which combine a mobile platform with a robotic arm, are versatile robots that can be used for a variety of tasks like logistic pick-and-placing, manufacturing or assembly. Compliant control for mobile manipulators could improve the safety of the users sharing their workspace with these robots. The two general methods of compliant control, admittance control and impedance control, require force/torque sensors, which are often not available on low-cost or lightweight robots. This report presents an adaption of impedance control, including a strategy to compensate for joint friction, that can be used on current-controlled robots without the use of force/torque sensors. A calibration method is designed for the arm, that enables estimation of the actuator's current/torque ratios and frictions, used by the adapted impedance controller. Software is developed to use the controller on a combination of the Kinova GEN3 Lite arm and the Clearpath Dingo Omnidirectional base. Real-world experiments with the arm show that the calibration method is consistent and that the designed controller is compliant while also being able to track targets with five-millimeter precision when no interaction is present. Experiments with the complete mobile manipulator showcase two new modes, both suitable for interaction with a human. The first is a guidance mode where the user can control the robot using interaction with the arm. The second is a tracking mode where the mobile manipulator tracks a moving target while still being compliant.","Impedance Control; Sensorless; Current Control; Mobile manipulator","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:1b2a2850-0b87-4d5b-890e-692c5d6e3053","http://resolver.tudelft.nl/uuid:1b2a2850-0b87-4d5b-890e-692c5d6e3053","3D Shape Optimization of Consecutive Manifolds using Free Form Deformation and Adjoint-Based Methods","van der Mark, Luuk (TU Delft Aerospace Engineering)","de Servi, C.M. (mentor); Anand, N. (mentor); Delft University of Technology (degree granting institution)","2024","Current design methods for oblique manifolds were first presented in the paper of London et al. in 1968. This method presents a single equation to shape the dividing manifold of several manifold configurations. However, current literature shows a potential to improve the current design method by implementing advanced techniques. This paper aims to bridge this gap by presenting an innovative design methodology incorporating these advanced techniques. The proposed design method integrates free-form deformation and adjoint-based methods within a 1st-order shape optimization framework. The objective function focuses on the minimization of mass flow mal-distribution, evaluated by an incompressible Reynolds-Averaged Navier-Stokes solver. Through three initial tests, this paper demonstrates a consistent improvement in the objective for all obtained designs. Noteworthy is the finding that small changes to the initial design lead to significant enhancements, evidenced by an 82.5\% decrease in the mass flow mal-distribution. Off-design testing further substantiates the effectiveness of the design method, showcasing superior performance under varying initial conditions for the optimized designs. Further testing not only exhibits improved objectives but also reveals common features among results for diverse initial designs. This paper shows a novel and effective design methodology for consecutive manifold systems, laying a robust foundation for an improved design method.","optimization; Free Form Deformation; Adjoint-based optimization; CFD Optimization","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:1e0cd006-a530-4743-8551-cf1cbf165245","http://resolver.tudelft.nl/uuid:1e0cd006-a530-4743-8551-cf1cbf165245","The Value of Travel Distance in Tourism travelling by Air: A Stated Choice Experiment","Ceha, Marlou (TU Delft Technology, Policy and Management)","Molin, E.J.E. (mentor); de Vries, G. (graduation committee); Zijlstra, T. (graduation committee); Krabbenborg, L.D.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Tourists travelling by airplane contribute significantly to the CO2 emissions. The number of flights covering longer distances is rising and, consequently, implies more energy consumption. This leads to a greater environmental impact compared to flights covering shorter distances. Although people are expected to continue travelling, adjusting the holiday destinations and modes of transport can effectively reduce the environmental footprint of tourism, all while maintaining pleasurable travel experiences. To minimize CO2 emissions by adjusting holiday destinations, destinations closer to home should be chosen. A trade-off seems to appear when selecting a holiday destination, involving a balance between the attractiveness of a specific destination and the different travel-related considerations. More attractive destinations can be reached with increasing distances, yet this also increases travel time and cost which are both preferred to be minimized. So far, research into the value of distance in this trade-off in the context of holiday destination choices is found to be limited. Therefore, this research studies how people value distance, controlling for travel time and travel cost, when choosing the destination for their holiday to gain a more comprehensive understanding of tourism travel behaviour. Since long-distance flights have larger CO2 emissions compared to flying over shorter distances, this study compares distances for holiday destinations that require long-distance flights with flights covering shorter distances. Additionally, these results can lead to interesting insights for policymakers. The main research question examined in this study is:
‘What is the value of physical distance for Dutch tourists in the choice of their summer holiday destination?’
For this study, a stated preference survey was created to collect data for addressing the research question, resulting in a sample of 254 Dutch tourists. To understand if distance holds intrinsic value, once controlling for travel time and for travel cost, and to investigate if the value of distance would change when travel time and cost are considered, two versions of a stated choice experiment are included in the survey. The respondents are randomly assigned to one of the choice experiments, resulting in half of the respondents completing one version while the other half completing the other.
Since people prefer different types of holidays, including all attractiveness attributes in choice sets may lead to many immediate ’no-go’ options. Therefore, the survey started with an additional experiment for all respondents. In this experiment, the respondents rated the attractiveness of different holiday destinations on a 10-point rating scale. A regression model was estimated based on the observed ratings. This gives an indication of the attractiveness of holiday destinations.
To investigate the intrinsic value of distance and if the value of distance changes considering travel time and cost, the results of the two versions of the choice experiments are estimated with a Multinomial Logit model. When comparing the results of both versions it was found that in version Choice experiment presenting all attributes a very small positive value exists, so small that it can be negligible. This suggests that once controlling for travel time and costs, there is no intrinsic value in distance. This was unexpected as it was expected that further distances would have a positive influence on the utility...","Distance; Tourism travel behaviour; Stated Choice Experiment","en","master thesis","","","","","","","","","","","","Engineering and Policy Analysis","",""
"uuid:2c4f8ca0-f44a-485a-99d6-d7952c902fa2","http://resolver.tudelft.nl/uuid:2c4f8ca0-f44a-485a-99d6-d7952c902fa2","Tackling the weathering with low ranks: Handling the complex near surface of land seismic data with low-rank-based methods","Alfaraj, Ali (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Verschuur group)","Verschuur, D.J. (promotor); Herrmann, F.J. (promotor); Delft University of Technology (degree granting institution)","2024","Imaging and inversion with seismic data recorded with sources and receivers at the surface are powerful tools to infer knowledge about the subsurface. However, creating an image with seismic data is unfortunately not as easy as taking a picture with a smartphone. The estimated subsurface models in many situations are far from ideal due to the low quality nature of the data. One of the reasons can be weathering of the near-surface geology that generates unconsolidated material characterized by slow velocity with rapidly varying, heterogeneous and season-dependent nature. Acquiring seismic data on such near-surface leads to complex wave propagation, posing challenges to imaging and inversion. In this dissertation, we tackle the weathering effects during seismic data processing, imaging and inversion with low-rank-based methods.
One approach to tackle the weathering effects on seismic data is removing them during seismic data processing. To do so for 2D data, we propose a model-independent low-rank-based near-surface estimation and correction in the midpoint-offset-frequency domain. In this domain, ideal data exhibit low rank structures, which get destroyed due to the influence of the weathering layers. Accordingly, the method makes use of the redundant nature of seismic data that allows for accurate approximation by low-rank matrices. To estimate the time shifts that compensate for the weathering effects, we cross-correlate a data set influenced by the near-surface weathering layers with its low-rank approximated version. Since we estimate time shifts (commonly referred to as statics) and no longer the directly low-rank approximated data, we avoid losses of the amplitude information. To improve the estimated statics and to alleviate the need for accurate rank selection for low-rank approximation, we implement the method in an iterative and multi-scale fashion. Since the low-rank approximation deteriorates at high frequencies, we utilize its better performance at low frequencies and exploit the common statics amongst different frequency bands. Using synthetic and field data, we demonstrate the performance of the proposed proposed, which requires no knowledge of the subsurface model, demands minimal data pre-processing, and provides accurate solutions with high computational efficiency compared to existing techniques.
When seismic data acquired on complex near-surface are additionally subsampled for economical reasons, such as monitoring of sequestrated carbon dioxide and hydrogen, the problem is further exacerbated. Both the weathering layers and randomized subsampling render coherent energy incoherent. Therefore, they both contribute to destruction of the low-rank structure commonly associated with statics-free densely-sampled data. Frugal data acquisition in complex near-surface regimes makes separation of the distinct sampling and weathering effects on the rank structure difficult, which as a result lead to poor reconstruction. To overcome that, we propose to reconstruct the data with joint rank-reduction-based near-surface correction and interpolation. The method simultaneously accounts for the weathering and subsampling effects to provide accurate reconstruction. Since low-rank approximation is used for near-surface correction, we also utilize it in rank-minimization interpolation as a cost-free initial solution to the optimization problem. As both near-surface correction and interpolation operate in the midpoint-offset domain, we avoid the cost of transformations back and forth from the source-receiver to midpoint-offset transform domain. Consequently, the proposed reconstruction, which shows its potential on synthetic and field data, additionally increases the computational efficiency.
While the aforementioned near-surface correction deals with 2D data, the Earth is a 3D object that requires acquisition of 5D data for proper subsurface model estimation. For 5D data, the limitations and challenges of conventional near-surface correction methods are magnified. To avoid them, we propose a 5D model-independent low-rank-based near-surface correction. To compute the singular value decomposition of 5D data volumes with 1 temporal and 4 spatial dimensions, which is necessary for low-rank approximation, we need to perform matricization of the 5D data, i.e. organization of the 5D data into matrices. At the same time, it is essential that the chosen organization domain reveals the underlying low-rank structure. Therefore, we first analyze different matricization domains that can be used to organize the 5D data. Similar to the 2D case, we show that --- in the potential domain --- the near-surface weathering layers render coherent energy incoherent, which results in slowly decaying singular values compared to the statics-free data that are of low-rank nature. The proposed method, which we show on synthetic and field data, enjoys the same benefits of the proposed method for 2D data, in addition to being able to capture the 3D nature of the Earth.
Due to the complex nature of the near-surface and due to its impact on the subsurface model, the near-surface model gets treated separately from the subsurface model. However, the optimal goal is not to remove the near-surface effects with data processing, but to accurately estimate near- and sub-surface models simultaneously. To do so, we use the inherent scale separation of joint migration inversion that estimates a low-wavenumber velocity and high-wavenumber reflectivity. Since rapid variations in surface elevation and near-surface model result in high wavenumber effects, they end up affecting the reflectivity model. At the same time, the estimated reflectivity influences velocity estimation. Consequently, JMI provides erroneous subsurface models in the presence of complex weathering layers. To mitigate that, we use multi-scale low-rank updates in the reflectivity domain. The proposed method reduces the near-surface effects at the initial iterations, but it allows more details of the near-surface model to enter the solution at later iterations. In the end, we estimate accurate near- and sub-surface models simultaneously without the need to bypass the weathering layers.","Near surface; Low-rank; Weathering; Interpolation; Imaging; Statics; Land seismic data; Velocity estimation; Inversion","en","doctoral thesis","","978-94-93330-65-8","","","","","","2025-03-06","","","ImPhys/Medical Imaging","","",""
"uuid:b3b976ed-4bcb-4adf-bcbc-82feeee42ba9","http://resolver.tudelft.nl/uuid:b3b976ed-4bcb-4adf-bcbc-82feeee42ba9","Numerical Analysis of Aerodynamic Cooling Ducts for Fuel-cell Powered Aircraft","Gudaal, Sakariye (TU Delft Aerospace Engineering)","Baars, W.J. (mentor); Kotsonis, M. (mentor); Delft University of Technology (degree granting institution)","2024","This thesis project undertakes a comprehensive numerical analysis of aerodynamic cooling ducts in the context of fuel-cell powered aircraft, aiming to enhance the efficiency and performance of these innovative propulsion systems. The use of fuel cells in aviation presents a paradigm shift towards sustainable and environmentally friendly air travel. However, the integration of fuel cells introduces new challenges, particularly in managing the excess heat generated during operation. Aerodynamic cooling ducts play a crucial role in dissipating this heat while minimising aerodynamic drag.
The numerical analysis involves the application of aerodynamics, thermal management and performance techniques to model and simulate the complex airflow within the cooling ducts. Parameters such as duct geometry, airflow properties, and heat transfer rates are systematically investigated to optimise the cooling process. The study also explores the interaction between the cooling ducts and the overall performance of the aircraft, considering the impact on drag and fuel efficiency.
This thesis uses an innovative approach to further enhance type annotation coverage in Python codebases by using a combination of machine learning predictions and combinatorial search. To do this, PyHintSearch was developed. PyHintSearch constructs a search tree to which a depth-first search is applied to systematically explore potential combinations of predicted type annotations and validate them using feedback from the Pyright static type checker. Ultimately, the goal is to identify a branch containing a valid combination of type annotations. These annotations can then be integrated into Python code, thereby enhancing the type annotation coverage, which leads to improved static analysis and ultimately better code quality.
PyHintSearch's effectiveness is evaluated based on type annotation coverage and correctness, performance, and practical usability. Experimental results demonstrate different improvements in type annotation coverage, depending on the machine learning model used for type inference. Type4Py showed an improvement of 62.45% and TypeT5 of 79.93%. The precision of type annotations from these models are 0.36 and 0.51, respectively. Performance-wise, PyHintSearch can efficiently explore the exponential search space, annotating 16 diverse projects, ranging from small to large, in approximately 13.75 hours when using the Type4Py model. Regarding practical usability, the impact of type annotations on downstream program analysis is examined through the generation of call graphs. The additional information that type annotations provide can be used to refine the call graph by eliminating irrelevant calls to make it more precise.","validated combinatorial search; probabilistic type inference; static analysis; type annotations; python; call graphs; machine learning type inference","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:8e32a52c-0019-42dc-962e-912377543df9","http://resolver.tudelft.nl/uuid:8e32a52c-0019-42dc-962e-912377543df9","Hybrid land/pontoon crane: Development of a removable connection system","Bajic, Tomi (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Marine and Transport Technology)","Jiang, X. (mentor); Schott, D.L. (graduation committee); Wijesinghe, C.S. (graduation committee); Pirija, Marko (mentor); Delft University of Technology (degree granting institution)","2024","An unfamiliar subject to the contemporary connecting options for cranes on pontoons is removability; Various difficulties and obstructions related to the heavy-duty nature of the equipment lead to a limited amount of practiced conventional connecting options for this purpose, which all have the absence of removability in common. Furthermore, the consideration of various types of efficiencies and performance aspects has not been common practice within this field. The aim of developing a removable and efficient crane-to-pontoon connection system is therefore set.
An initial literature research is performed in order to obtain a variety of connecting options which have the potential of forming the basis of a new removable connection system, optimized for crane-to-pontoon configurations. Subsequently, creating a unique rating system, specifically for crane-to-pontoon connection systems, led to a substantiated selection process for the most feasible option among the potential connecting options. The turnbuckle option obtained the highest ranking and was therefore selected to proceed the design process with.
Developing the turnbuckle option into a complete connection system and accomplishing all defined aims led to an encounter with various engineering challenges. An integral design process led to the discovery of a proficient combination of components, which overcome the challenges and provide satisfaction with respect to the aims of the project.
The parameters of the developed conceptual design are finally quantified in order to prove feasibility and efficiency. Applicable design parameters are found which pass the safety requirements, while minimizing the material consumption. With these parameters, the removable design is compared to conventional real case connection systems in terms of cost-efficiency, which resulted in the observation that multiple millions of euros in long-term savings are anticipated per deployed crane due to the removability feature.
Approximately 9 in 1000 children are born with congenital heart disease (CHD), of whom a quarter are classified as critical CHD (CCHD) and require an intervention within their first year. Monitoring these patients in the Paediatric Intensive Care Unit (PICU) is crucial, yet with increasing amounts of data, detecting subtle changes that are important for the disease progression interpretation of all vital signs becomes difficult, even for skilled physicians. Machine learning (ML) offers potential solutions, however, challenges such as inter-patient variability and the absence of clear definitions for haemodynamic instability persist. This study aims to develop a ML algorithm for early prediction of haemodynamic instability in CCHD patients with high frequency vital-signs, addressing these challenges through objective labelling methods and stratification approaches.
Methods
Two approaches, on population and patient level, were developed with nested cross-validation (CV). Due to a high inter-patient variability, the patient specific approach was added. A first iteration of objectively labelling haemodynamic instability was proposed, based on medical interventions such as medication administration and fluid therapy. Since it is difficult to retrospectively determine for how long patients were unstable, multiple values for instability duration (dT ) were added to the analysis.
To capture the temporal dependency of time-series data, lag-analysis was performed, adding the relation between the vital signs and their previous values to the model development. Lag-analysis included a sliding window that moved over the data. The width of sliding window (W ) was optimised during the model development. Additionally, a horizon (r ) was implemented, so the data within the sliding window were predicting future timestamps.
Results
This retrospective study included a total of 224 admissions in the analysis. Two random forest classifiers were trained using a nested CV structure to detect haemodynamic instability in CCHD patients. For both approaches the same temporal settings (W : 50 minutes, r : 45 minutes, dT: 120 minutes) were used. This study has shown that the between-patient approach had notable differences between the mean train (85%, AUCPR) and test performance (40%, AUCPR). The in-patient approach, while using 20% and 10% of the test data for training, still yielded a test performance of 96% (AUCPR) and 90% (AUCPR), respectively.
Discussion and conclusion
Generally speaking, the experiments suggest that the first iterations of the models were not robust and generalised poorly. It is most likely caused by a large inter-patient variability and a simple labelling system that is still depending on subjectivity.
This study has shown that the proposed prediction model, which combines high frequency vital signs, labels, and temporal settings (W, r, dT ), requires additional refinement before it can be considered clinically feasible to implement this model as a reliable bedside tool for predicting haemodynamic instability.
To adequately respond to reported crimes, police officers in the control room and units on the street rely on intuition, experience, and habit. This leads to the development of individual-specific strategies for handling interception scenarios. Reducing the dependency on these individualized approaches by identifying proven and robust strategies could increase the likelihood of successfully capturing a suspect. However, how the police currently save data on fugitive interception scenarios does not allow for such identification. Hence, alternative approaches to overcome this limitation must be found. Therefore, this paper explores whether simulation and game theoretic analysis are suitable methods for determining robust interception strategies for the police, aiming to increase the catch rate in fugitive interception scenarios.
Classical game theory is the mathematical theory of interactions among rational decision-makers with opposing interests. It offers valuable insights into the decision-making processes, compromises, and strategies the police and offenders may employ in real-world situations. To analyze the fugitive interception scenario with game theory, it is first simulated with an agent-based model. In this simulation model, the police and offender are individual agents with opposing interests and individual decision-making processes. Before modeling, research is conducted to find the current strategies that the police and offenders can potentially adopt.
Given the limited availability of data on fugitive interception scenarios, literature and expert interviews serve as sources for data collection. They provide insights into the behavior and strategies of both agents. Both sources emphasize the nature of the crime as a primary indicator of the offender's escape behavior. Large crimes, such as assassinations or armed robberies, are typically well-planned and characterized by predefined escape routes and rational behavior. During their escape, offenders of large crimes are found to be less susceptible to external factors such as crowd flows or police sightings. On the other hand, smaller crimes are more frequently committed spontaneously and associated with bounded rational behavior. This is depicted by their chaotic and unpredictable escape routes while taking many turns.
For the game theoretic analysis, the results of the simulation model are analyzed. The fugitive interception project is regarded as a non-cooperative zero-sum game. The results are presented in a payoff table, in which Nash equilibria are calculated. Nash equilibria are the points at which no player can single-handedly improve their outcome when the other player does not change strategy.
The pure-strategy Nash equilibrium resulted from the offender strategy where they started at a central metro station and aimed to transfer to a train network. These routes were frequently identified as the shortest compared to other end goals. Conversely, strategies that focused on getting as far away as possible, as quickly as possible, were found to be the least successful.
In determining the success of the police strategy, two factors were found to be crucial. Firstly, strategies where the police conducted surveillance on the metro platforms, as opposed to the station exits, proved significantly more effective. This highlights the importance for the police to strategically position themselves where the offender is most likely to pass, irrespective of assuming it to be the offender's final destination. Secondly, the police's response time served as an indicator for capture success. The quicker the crime is reported, the faster the police can take action to capture the offender, which increases capture chances.
Additionally to the game theoretic analysis, the relationship between the model’s output and its sensitivity to changes in input variables is tested. Results showed that variations in input did not lead to significant changes in output. This can be attributed to the deep uncertainty of this model. To address this challenge, the model must be refined, and done with more iterations.
In conclusion, by combining simulation and game theory new insights can be found beyond what either method can provide individually. By modeling the dynamic nature of a fugitive interception scenario, the success of the offender and police behaviour can be found. This can help the police during decision-making to adopt more robust strategies while considering the dynamic nature of the environment and strategic interactions with the offender.
The study addresses the knowledge gap by simulating offender and police behavior, and analyzing the result with classical game theory. This study has created a simulation model with an intuitively driven agent in a complex dynamic problem. Potential improvements in offender capture chances, with findings informing effective and unbiased police interception strategies. The study aims to contribute to crime reduction and foster increased trust in the Dutch national police. However, before generalizing the results future research must be done to overcome limitations resulting from the simplifications of this simulation model.","","en","master thesis","","","","","","","","","","","","Engineering and Policy Analysis","",""
"uuid:e0b81afd-0a66-47da-8ff3-f51345d1fc12","http://resolver.tudelft.nl/uuid:e0b81afd-0a66-47da-8ff3-f51345d1fc12","Schematization uncertainties in the macrostability safety assessment: Case study for primary dikes in the Alblasserwaard","Naaktgeboren, Mariska (TU Delft Civil Engineering & Geosciences)","van den Eijnden, A.P. (mentor); Lanzafame, R.C. (mentor); Kapinga, Sander (mentor); Arends, Martin (mentor); Delft University of Technology (degree granting institution)","2024","The current macrostability safety assessment for primary river dike trajectories in the Netherlands is applied to approach the failure probability of a dike during high water events. However, in the current schematization process that is described in the Wettelijk Beoordelings Instrumentarium (WBI) to assess the macrostability, aleatory and epistemic uncertainties are approached ’sufficiently safe’ by applying design values based on expert judgement via a semi-probabilistic assessment. Several primary river dike sections in the Alblasserwaard do not suffice the current safety standard set for the failure mechanism macrostability. The region is composed of a highly complex subsurface with large spatial variation, resulting in large schematization uncertainties for the macrostability assessment of the primary dike trajectories of the Alblasserwaard. With the recent development of full-probabilistic analysis possibilities in software such as D-Stability, it becomes possible to consider uncertainties as a stochastic variable in the macrostability safety assessment. Including schematization uncertainties within the macrostability safety assessment will improve the approximation of the failure probability of the primary dike trajectory. The largest schematization uncertainties in the macrostability safety assessment are currently considered to be the schematization of the subsurface in a vertical soil profile and the uncertainties in the schematization process of the pore water pressures in the dike during high water events. These uncertainties will be included in the calculation process to investigate the influence on the expected reliability of the primary dikes in the Alblasserwaard region. The subsurface schematization uncertainties are investigated by using soil scenarios to investigate the influence of local subsurface schematization in the vertical soil profile. The simplification of the soil profile and position of the soil layers is considered. The pore water pressures are separated into three components: the hydraulic head in the aquifer, the intrusion length, and the phreatic line. Each component will be included as a stochastic variable in the stability analysis. Fragility curves can be applied to describe the distribution function for each pore water pressure component, where the combined fragility curve will provide the combined failure probability and reliability index that includes the schematization uncertainty of the pore water pressures considered.
The soil scenarios can be applied to include schematization uncertainties of the subsurface in the macrostability safety assessment. The analysis showed that the simplification of the subsurface schematization only has a minor influence on the reliability index and failure probability of the case study dike cross-section Kortenhoevendijk. The schematization uncertainties of the pore water pressures can be considered in the macrostability safety assessment by combining the fragility curves of each component describing the pore water pressures underneath the dike. Results of the pore water pressure analysis are that failure probability is improved significantly for case study Kortenhoevendijk by a factor 1000 and case study Bergstoep by a factor 10. The approach to consider schematization uncertainties in the macrostability safety assessment via a full-probabilistic analysis can be used for dike sections prone to the uplift mechanism. This approach provides insight into the influence of schematization uncertainties on the failure probability of a dike cross-section. Including the pore water pressure schematization uncertainties in the macrostability safety assessment can have a significant impact on the outcome of the assessment. Including these uncertainties can make the difference between deciding whether a dike trajectory needs reinforcement, or deciding that reinforcement is not necessary.","Macrostability; Dike reliability; Flood Defence; Flood management; Netherlands; Primary Flood Defenses","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:e3196d4d-1ed1-4be7-b791-7a9cd471d576","http://resolver.tudelft.nl/uuid:e3196d4d-1ed1-4be7-b791-7a9cd471d576","Creating a continuous outbound flow at the flower auction: A case study at Royal FloraHolland Naaldwijk","Gerritsen, Anouk (TU Delft Civil Engineering & Geosciences)","Vleugel, J (mentor); Duinkerken, M.B. (mentor); Negenborn, R.R. (mentor); Abels, Ingrid (graduation committee); Binneveld, Oscar (graduation committee); Delft University of Technology (degree granting institution)","2024","This paper investigates how two sequential sub-processes at a flower auction can be well aligned to efficiently execute the overall auction process. Existing literature mainly focuses on warehouses without perishable goods and warehouses where all orders are known before the outbound process is started. However, at a flower auction, the gathering of goods and distribution takes place while the auction is still ongoing. In addition, flowers are vulnerable goods that must be handled with care.
During a case study at Royal FloraHolland Naaldwijk, the current process of order picking and in-house delivery is investigated to find the main strengths and bottlenecks. This is done physically and with data. From this analysis,
it has been found that the main issues are the spread and share of waiting times in the in-house delivery process and the output of the order-picking process that is too low. To improve the overall process based on the found issues, a calculation model has been built in Python to test possible improvements. It has been found that implementing limited waiting times and other alterations to increase efficiency results in a more reliable and better predictable
process that can be executed with approximately the same number of work hours or slightly more than in the current situation.","Auction; Outbound flow; Order picking; In-house delivery","en","master thesis","","","","","","","","","","","","Transport, Infrastructure and Logistics","","51.998374, 4.229874"
"uuid:6f280f18-8d27-499d-b37b-baefbcb3dc7f","http://resolver.tudelft.nl/uuid:6f280f18-8d27-499d-b37b-baefbcb3dc7f","A strategic design approach for attracting and retaining Generation Z: Redesigning Yonderland’s fading loyalty programs into a paid membership service that is tailored to Gen Z","van Tooren, Tim (TU Delft Industrial Design Engineering)","Hultink, H.J. (mentor); Brouwer, W. (graduation committee); van de Leur, Floor (graduation committee); Delft University of Technology (degree granting institution)","2024","This Master’s thesis investigates strategies for Yonderland, Europe's largest premium outdoor retailer, to attract and retain Generation Z, a demographic not previously targeted by the company. Through extensive research, including qualitative and quantitative methods, a literature review, interviews with stakeholders, and multiple creative sessions, a comprehensive strategy was formulated for Yonderland and the focus subsidiaries — Bever, A.S Adventure, and Cotswold Outdoor — to appeal to Generation Z's unique preferences and behaviors. Key findings reveals Generation Z, born between 1995 and 2010, as digital natives who value social consciousness, authenticity, and transparency in their brand interactions. This demographic heavily relies on social commerce and peer recommendations, incorporating digital seamlessly into their lifestyles, which influences their loyalty and purchasing decisions. Despite an interest in premium outdoor products, Yonderland initially overlooked the potential of engaging with this demographic, missing significant sale opportunities. The research suggests a strategic pivot towards building authentic connections with Generation Z by emphasizing environmental and social values, and utilizing digital platforms like TikTok for effective engagement. Highlighting the role of over a million Gen Z creators on social media, the strategy focuses on leveraging these influencers to foster genuine interactions and product discovery, emphasizing the importance of authenticity and relatability in marketing efforts. The research critiques Yonderland's existing loyalty programs for their transactional focus, which fails to resonate with Generation Z's values of self-expression, inclusivity, and personalization. It further identifies issues such as a one-size-fitsall approach, lack of meaningful customer journey integration, and underutilization of customer data for personalized experiences. This misalignment underscores the need for a strategic overhaul of Yonderland’s loyalty programs to resonate with Generation Z’s values of self-expression, inclusivity, and personalization. To address these challenges, the thesis suggests an overhaul of these programs to better align with Generation Z's expectations, needs and values. It proposes a shift towards a premium paid membership propositions that emphasizes customer engagement, community building, and personalization through the introduction of a Customer Data Platform, Atelier Café, and Membership App. The new strategy aims to enhance customer engagement, loyalty, and community building, positioning Yonderland to better meet Generation Z’s sophisticated needs while redefining retail customer experiences through connectivity and a focus on sustainability. The Customer Data Platform is designed to enable Yonderland to play a more relevant role in their customers’ digital lives, transitioning from fragmented customer insights to a comprehensive understanding of customer needs and behaviors. This marks a shift towards more relevant digital engagement. The Atelier Café is introduced as a community hub for member events, circularity, and craftsmanship, serving as a focal point for community engagement, workshops, and events that resonate with Generation Z’s values focused on sustainability and craftsmanship. Meanwhile, the Membership App enhances discovery, community, and personalized experiences across its Discovery, Shop, Service, and Community Pages, revolutionizing Yonderland’s engagement and diverging from conventional retail practices towards embracing sustainability and community. This integrated approach signifies a move away from traditional retail models, fostering a more connected and personalized customer experience. This approach, along with leveraging TikTok as the primary marketing channel and launching the Member Days, aligns closely with Generation Z’s preferences, aiming to boost brand visibility, loyalty, and growth by fostering authentic connections. To seamlessly integrate this new paid membership proposition into Yonderland’s offerings, a futurestate service blueprint has been developed alongside a strategic roadmap. The thesis concludes that Yonderland can successfully attract and retain Generation Z by aligning its strategies with the demographic's preferences for authenticity, community-building, and environmental and societal values.","Customer Loyalty; Membership; Generation Z; Social commerce; Loyalty Programs","en","master thesis","","","","","","","","","","","","Strategic Product Design","",""
"uuid:bc872e8f-61e9-43ac-b891-78d35497194c","http://resolver.tudelft.nl/uuid:bc872e8f-61e9-43ac-b891-78d35497194c","Operational limits of 2XL monopile installation: A comparative analysis of side and stern installation","Elzinga, Anke Marij (TU Delft Mechanical, Maritime and Materials Engineering)","Gelling, J.L. (mentor); Kana, A.A. (graduation committee); Stroo, J.D. (graduation committee); Delft University of Technology (degree granting institution)","2024","The offshore wind energy sector is rapidly growing with an increase in the capacity of offshore wind turbines, resulting in increasing dimensions of offshore wind turbines and their foundations. Additionally, there is a tendency to locate offshore wind farms more offshore because of more consistent wind speeds and more space. Sites with a water depth less than 70 metres are suitable for fixed-bottom foundations. A commonly applied fixed-bottom foundation is the monopile due their simplicity, ease of installation, and relatively low costs. Over the past years, the diameter of the monopile increased from an average of 5 metres tot 10-12 metres. These ever-growing monopiles need to be installed from floating vessels, such as heavy lift crane vessels, which are not dependent on water depth, instead of jack-up vessels. During installation, heavy lift crane vessels form a multi-body system with the crane and monopile and pile gripper ring, inducing coupled dynamic behaviour, resulting in resonance behaviour.
Currently, monopiles are installed at the side of a heavy lift crane vessel. However, a new technology is in development to install monopiles in a recess at the stern of the vessel. The upending and lowering of stage of monopile installation are considered as critical events and it is obligatory to assess the operational limits of these stages during the planning phase. The purpose of this thesis is to compare side and stern installation of 2XL monopiles from a heavy lift crane vessel during the upending and lowering phase in terms of operational limits. Therefore, a case study is performed, using Hornsea Offshore Wind Farm on the North Sea as a reference project. Time-domain simulations are conducted in OrcaFlex for various significant wave heights and spectral peak periods for both side and stern installation. The operability of the mission equipment is assessed, resulting in a comparison for side and stern installation. It is found that during upending stage, stern installation provides a larger operability window compared to side installation. During the lowering stage, side and stern installation have a comparable operability window. In conclusion, stern installation shows promising results to further develop this installation method.","","en","master thesis","","","","","","","","","","","","Marine Technology | Ship Design","",""
"uuid:bf291028-ef7e-4a6c-9a22-9bae9fde591c","http://resolver.tudelft.nl/uuid:bf291028-ef7e-4a6c-9a22-9bae9fde591c","Rethinking Privacy in the Age of Social Robots","Coggins, T.N. (TU Delft Ethics & Philosophy of Technology)","van de Poel, I.R. (promotor); Kudina, O. (copromotor); Delft University of Technology (degree granting institution)","2024","In the introduction of this thesis, I contend that robot ethics, as a research field, generally treats privacy as the appropriate distribution of information, and therefore overlooks privacy concerns raised by robots beyond this conceptualization’s purview. I illustrate this contention by evaluating a hypothetical case involving a household companionship robot via contemporary robot ethics literature focusing on privacy. I argue that this corpus cannot identify a variety of privacy concerns raised by such robots because it relies on a narrow interpretation of privacy that can only recognize privacy harms of an informational nature. I posit that privacy represents considerably more than implied by the interpretations offered by robot ethicists. Most crucially, it signifies our need to withdraw sporadically from social engagements. Considering that robots - like the one described in the case mentioned - simulate what it is like to interact with other humans, I argue that such machines will produce privacy concerns when they successfully create the impression that another person is present during moments when their users wish to be left alone. I highlight that some researchers from robot ethics have discussed issues of this kind but rarely frame them as privacy concerns, thus leaving a significant literature gap I attempt to fill via my research. I conclude the introduction by presenting a close reading of relevant privacy scholarship to evidence the claims made above and lay the theoretical foundation for the dissertation....","privacy; social robots; human-robot-interactions; housework; norms; performativity; robot ethics","en","doctoral thesis","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:a338e143-50ee-4954-afac-73f8f049d581","http://resolver.tudelft.nl/uuid:a338e143-50ee-4954-afac-73f8f049d581","Visual quantification of motor function during awake brain surgery: Towards a Neuro Research Operating Room","Gommers, Emma (TU Delft Mechanical, Maritime and Materials Engineering)","Kruizinga, P. (mentor); Mugge, W. (graduation committee); Satoer, D. (Djaina) (mentor); Vincent, A.J.P.E. (Arnaud) (mentor); Delft University of Technology (degree granting institution)","2024","During a brain tumour resection, a neurosurgeon is constantly navigating a delicate balance between resecting as much of the tumour as possible, while avoiding any damage to healthy brain tissue. This challenge is particularly difficult when the tumour is located in a critical functional area, involved in for example language or motor function. For these types of tumours, the awake craniotomy was developed. During this surgery the patient wakes up to perform language and motor tasks, to enable the surgeon to localize these functions inside the brain. In this thesis, we investigate and develop a new quantitative method to monitoring motor function that could potentially improve intraoperative decision making and enables neuroscientific and neurosurgical research.
Chapter 1 provides a background about surgical strategies and technologies that have been developed to aid surgeons’ decisions during complex brain tumour resections. We will explain the complexity of robust research in the neurosurgical environment and the need for a dedicated Research Operating Room to create an environment to improve neurosurgical and neuroscientific research.
In Chapter 2 we make an overview of the possible solutions to quantify motor function before, during and after awake craniotomies and discuss the best solution for the Erasmus MC.
In Chapter 3 we present a new frame to create a standardized environment inside the operating room for good quality data collection of patient functionality. To design this frame, we identified and interviewed all the important stakeholders and designed three prototypes. The two most promising prototypes were developed. The final prototype was implemented during three awake craniotomies.
This newly developed frame was used in Chapter 4 to explore video tracking as a new tool to quantify hand motor function. Three patients were followed one day prior to the surgery, during the awake craniotomy, and one day postoperatively. During these three cases, we identified several prerequisites for a reliable recording set-up and explored the potential to detect clinically relevant events during fingertapping and direct electrical stimulation (DES). This showed promising results and underscores the potential for video tracking to be further investigated for quantification of hand motor function.
In Chapter 5 we put the discussed work into context, discussing it’s clinical and scientific relevance and future perspectives. In this thesis, we have demonstrated that it is possible to implement a new quantitative measurement method to monitor hand function in the challenging environment of an operating room. Quantification of visual observations has shown to be low-cost, easily available and implementable in clinical context, because of the fast technological advancements in this field. Video tracking can be used for future research to investigate the relation between intraoperative findings and long-term outcomes, and has the potential to add valuable information for neurosurgical and neuroscientific research.
The waste stream of EOL steel scrap is heterogeneous and contaminated, complicating existing recycling routes used for industrial scrap. A way to combat the contamination is to apply heat treatment to the EOL scrap. This study investigates the implications of heat treatment on EOL tinplate, a tin coated steel product used for packaging.
Tin is considered a tramp element in a steel melt, thus the coating must be removed before recycling. Heat treating tinplate causes the tin coating to form an intermetallic alloy with the steel substrate, as a result tin atoms become more difficult to separate from the steel scrap product. The reduction/oxidation behaviour of the two most prevalent tin-iron intermetallic alloys, FeSn2 and FeSn, has been mapped through Cyclic Voltammetry(CV) in both an alkaline and acidic electrolyte. Pure tin and the steel substrate of tinplate scrap were similarly investigated to compare all elements in the system. The goal is to achieve if selective separation and recovery of tin. Further analysis of the anodic dissolution through Chronoamperometry(CA) analysis allow insight in how the current response over time. Based on the CA results, a detinning process is tested over trials of new industrial scrap and EOL municipal scrap. The process has a high detinning rate for new scrap, while for EOL scrap the detinning is hindered by a presence of paint or lacquer. Trials on heat treated EOL scrap showed a small reduction of the negative impact of lacquers and paint. At the same time it was observed that most of the free tin transformed into FeSn2.
The data from Cyclic Voltammetry, Chronoamperometry and detinning trials were used to propose a possible detinning line design for heat treated EOL tinplate scrap.
This thesis implements a model-free, feedforward controller based on wave preview for the above-rated region of a FOWT. The controller uses a preview of wave forces acting on the floating platform and aims for simultaneous rotor speed regulation and platform motion reduction using collective blade pitch control. As a model-free approach, a modified Data-enabled Predictive Control formulation that considers past and future information about measurable disturbances is proposed. The controller is implemented with a linear model of the NREL 5-MW wind turbine installed on the OC3-Hywind spar-buoy platform and tested in several cases. The effectiveness of the wave feedforward data-driven controller is evaluated in a high-fidelity environment using the QBlade simulator. A decrease in rotor speed variance of 67% and platform pitching motions of 71% is obtained, at the cost of a 7-fold increase in blade pitching effort compared to the baseline controller. In turbulent wind conditions, the wind proved to be the dominant disturbance, and including both wind and wave previews in the controller is recommended. This work demonstrated the feasibility of a model-free feedforward control strategy for wave effect mitigation in FOWTs. Further efforts are required to adapt this strategy to closed-loop operation and to validate its effectiveness across the entirety of the above-rated region.
A design framework is proposed to construct digital models to support a DT for retrofitting purpose. The proposed framework is tested on a case-study using a 300-meter bulk carrier. Since January 2019, operational ship data is collected through BDNs, a mandatory data collection method for ships of 5000 GT and above, adopted by the IMO. Constructing a DT based on BDNs is considered to be convenient as it provides a solid source of operational data in the future.
First, the available data from the BDNs is preprocessed using an adopted framework based on data science literature. The resulting 5,678 data points are used for the construction of a model representing the bulk carrier and a model representing the green ship technologies part. A fuel consumption model is constructed to represent the bulk carrier. It utilizes a gray-box modeling approach, consisting of a white-box resistance model and a black-box artificial neural network. Both models incorporate environmental-dependent inputs. The investigated green ship technologies for the potential retrofit are represented by various wind-assisted ship propulsion (WASP) systems, namely a towing kite, a DynaRig sail, and a Flettner rotor. These systems are modeled using a white-box modeling approach, together with available wind data. Using an adopted integration framework, based on the propeller-engine matching procedure, both representations are combined into one green ship digital model.
An environmental assessment is performed using the IMO's EEXI and CII assessment tools, respectively evaluating the design and operational aspects of the potential retrofit. Additionally, a financial assessment is conducted using the payback period. Results showed the design implications and emissions reduction potential of implementing such systems which will guide the retrofit decision by the ship's owner.
This thesis examines the role of co-creation in local energy cooperatives and highlights its importance in promoting sustainable energy practices and empowering citizens. It focuses on investigating co-creation within the energy cooperatives of the Metropolitan Region Rotterdam The Hague (MRDH) and connects theoretical concepts with practical applications in energy transition. The central research question is: ”In what ways does co-creation manifest within local energy cooperatives in the Metropolitan Region Rotterdam The Hague?”
A literature review was conducted using the PRISMA method and snowball technique to understand the academic perspectives of co-creation, especially in energy transition. This helped identify the scope of the thesis and gaps in current academic knowledge. The thesis contains two theoretical frameworks. The first, from Puerari et al. (2018), examines the dynamics of co-creation in local communities and identifies five key elements: intended purpose, process type, ownership, motivations and incentives, and spaces and places. This research applied these elements to understand co-creation in MRDH’s local energy cooperatives through qualitative case study analysis. The analysis reveals the cooperatives’ commitment to fossil-free energy and their encouragement of citizen participation through a mix of formal and informal methods, addressing different motivations and adopting a shared ownership model to promote community involvement.
The second framework consists of six criteria that define co-creation activities. These criteria are developed in this study, and derived from academic literature. These criteria include shared goals, active participation, equality and inclusiveness, iterative processes, value creation and mutual learning. Subsequently, the study used these criteria to evaluate the activities of energy cooperatives and assess their alignment with the concept of co-creation. Through interviews and observations, four key cooperative activities were identified: advisory services, information generation, renewable energy production and stakeholder engagement. While these activities meet the criteria for co-creation, there are opportunities for improvement in almost all areas of co-creation to fully realise the potential of these activities.
The findings suggest that cooperatives should organise regular stakeholder discussions, introduce paid functions, make more effective use of physical spaces, promote diversity and develop digital platforms for knowledge sharing. Policymakers can support these cooperatives by recognising their contributions, encouraging professional development and encouraging flexibility and innovation. Future research recommendations address the limitations of this study such as regional focus, time constraints and possible subjectivity of the qualitative method. Suggestions include expanding the geographical scope, involving a wider range of stakeholders, using mixed methods and testing the recommended strategies in different contexts.
In summary, this research is an important step in understanding co-creation manifestation within local energy cooperatives. It suggests strategies through which these cooperatives, in collaboration with policymakers, can effectively contribute to environmental sustainability and climate change mitigation.
This research aims to improve the understanding of large-scale morphodynamics in sandmud tidal systems. This is done by investigating processes related to long-term deposition, sediment supply, sand-mud interaction, and segregation of sand and mud. We focus on generic idealized cases, as well as on case studies in the Wadden Sea — an example of a heavily-impacted system whose existence is threatened by sea level rise (SLR). Unique long-term data sets of its hydrodynamics, bathymetry and sediment composition are available, making this an excellent area to study the morphological responses to human interventions in detail, and to improve our understanding of sand-mud morphodynamics.
Analysis of the morphological evolution after a closure in the Western Dutch Wadden Sea (Chapter 2) illustrates the importance of distinguishing between the response of sandy and muddy sediments when analyzing the morphodynamic impact of an intervention. Our findings reveal that sand and mud respond on different temporal and spatial scales. Moreover, the results show that the contribution of mud to the total infilling was much larger than the average mud content in the top layer of the bed, because mud preferentially deposits in areas with high net sedimentation rates. This demonstrates that the contribution of sediment types to morphological change is not necessarily reflected by the spatial bed composition.
Up to now, the availability of mud to the Wadden Sea was poorly known, while we know that this availability is crucial for predicting the response to future climate change. Therefore, a first system-wide mud budget of the Wadden Sea has been developed (Chapter 3), revealing a nearly closed balance between the sources and the sinks. This observation implies that disturbing the mud balance at one location will impact downdrift areas. Anthropogenic sediment extraction provides the second largest sink, even surpassing salt marsh deposition. Field data suggest that a mud deficit already exists in some areas of the Wadden Sea, which will only become more pronounced with increased SLR rates. Mud is thus a finite resource similar to sand, and should be treated as such in sediment management strategies. Furthermore, local interventions may have consequences in downdrift areas, stressing the need for a cross-bordering perspective.
The influence of small-scale sand-mud interaction on large-scale modeled morphodynamic development has been studied by implementing two abiotic interactions (erosion interaction and roughness interaction) in a process-based model (Chapter 4). Model output was converted into metrics that describe the macro-scale configuration of the modeled systems, allowing a quantitative comparison of scenarios. The results demonstrate that sand-mud interaction can significantly impact tidal basin evolution, especially having a large influence on the intertidal flat shape, size and composition.
Lastly, we have seen that the mud content of the sediment bed in tidal systems is often bimodally distributed, indicating a preferential sand-mud segregation (Chapter 5). Bimodality represents the existence of two stable equilibrium conditions, which result from sediment deposition processes (and not erosion processes), and can be expected for a large range of suspended sediment concentrations in sand-mud systems. In order to correctly reproduce this bimodal character in process-based models, and therefore correctly modeling the bed sediment composition, one must account for erosion interaction in the model set-up — despite the role of deposition as a driving mechanism.
In conclusion, this dissertation illustrates the importance of a sand-mud perspective in morphodynamic studies, considering the contribution of both sediment types to the morphodynamic development as well as their interactions. We have seen that advancing our understanding of sand-mud morphodynamics requires combined data-based and modeling approaches, adopting a system-wide perspective, and considering the interactions between the various spatial and temporal scales. Morphological metrics, such as the ones that have been presented, are essential for the evaluation and comparison of model results and coastal morphology worldwide. Enabling successful and sustainable management of coasts and deltas will require further increasing our understanding of sand-mud morphodynamics through additional measurements and modeling studies. Developing a system understanding should be at the heart of all of these studies.","sand-mud; morphodynamics; tidal basins; Wadden Sea; numerical modeling","en","doctoral thesis","","78-94-6366-816-3","","","","","","","","","Coastal Engineering","","",""
"uuid:b265aa7e-fb37-42b9-9104-c00f5d3e0453","http://resolver.tudelft.nl/uuid:b265aa7e-fb37-42b9-9104-c00f5d3e0453","Smart Grid standards policy in context: A discursive-institutionalist analysis of government intervention in the European Union and the United States","Muto, M.S. (TU Delft Organisation & Governance)","Herder, P.M. (promotor); de Bruijn, J.A. (promotor); Delft University of Technology (degree granting institution)","2024","Starting around 2005 and for several years, the creation of a “Smart Grid” became a key element in the quest of policymakers to operationalize the goal of “sustainable development”. In official discourse, the Smart Grid promised improved energy security and a way to support the realization of ambitious targets on reduced carbon emissions and increased use of renewable resources. Additionally, the Smart Grid was presented with the lure of “green innovation” and jobs.
The imperative of realizing these vision(s) of the Smart Grid put unprecedented focus on the world of ICT standardization. Without an agreed set of interoperability standards, promising pilot projects would not scale in a meaningful way, and the European Union (EU) and the United States (US) federal government departed from established practice within this policy domain and intervened to encourage, coordinate and accelerate standardization activities.
This thesis explores how such a policy of intervention was constructed in EU and US official policy texts. It does this by building a conceptual framework with elements from discourse theory and neo-institutionalism that aims to understand the factors of policy change in a highly technical area in the absence of crisis or repeated policy failure. How is the need to develop an agreed set of ICT interoperability standards understood as a policy problem, and how is intervention in the standardization process legitimated? What does the policy response to the challenge of Smart Grid standardization say regarding current understandings about the proper role of government and the potential for industry self-organization in policy areas relating to new technologies?
In pursuing the above questions, this thesis contributes to our understanding of a field that is under-developed yet of growing importance. As our societies are increasingly attempting to solve important challenges through the large-scale application of ICTs (Smart Transport, Smart Homes, Smart Cities), we need a better understanding of policy alternatives that go beyond the typical dichotomy of legislation versus self-regulation.","","en","doctoral thesis","","","","","","","","","","","Organisation & Governance","","",""
"uuid:4305fef1-fa58-4223-a988-498609f166d8","http://resolver.tudelft.nl/uuid:4305fef1-fa58-4223-a988-498609f166d8","Modelling the Influence of Non Conforming Stirrup Detailing on Shear Capacity of Existing Reinforced Concrete Beams","van Dijk, Bob (TU Delft Civil Engineering & Geosciences)","Yang, Y. (mentor); Ibrahim, M.S. (mentor); Rots, J.G. (graduation committee); Hendriks, M.A.N. (graduation committee); Jongstra, B. (mentor); Delft University of Technology (degree granting institution)","2024","In the Netherlands, numerous bridges face reassessment. During this assessment, it is observed that in some cases, the applied shear reinforcement (stirrups) does not meet the detailing requirement given in the national annex of the NEN-EN 1992-2. This requirement, which states that the stirrups must enclose the longitudinal reinforcement to ensure adequate anchorage, is referred by the RBK. This guideline calculates the shear capacity by combining the concrete and the stirrup contribution. However, the contribution of the stirrups can only be included when the detailing requirement is satisfied. In this research, a case study is used in which stirrups are applied that do not meet this requirement. These stirrups are expected to still contribute to the total shear capacity. Therefore, the main aim of this research is to develop a model that can predict the shear capacity by including the anchorage influence of these non conforming stirrups.
In this research, a layered approach is modeled to determine the shear capacity. This approach divides the cross section into several layers, and each of these layers is individually analyzed with the Modified Compression Field Theory (MCFT). The next step in the development of the model is to implement the anchorage behavior. There are two rebar anchorages included in this research; the straight and hooked rebar anchorage. Separate approaches are used to determine the anchorage capacities, which are based on existing experimental research. In both approaches, the axial stress in the applied shear reinforcement could be limited to these anchorage capacities.
Due to the limited availability of experimental research on reinforced concrete beams with non conforming stirrups, this research includes a constrained validation of the model. Subsequently, the shear capacity of the bridge within the case study is predicted. The first cross section in the span region, where the hooked rebar anchorage is governing. As a result of the high anchorage capacity, little influence is observed in the shear capacity of this cross section. The straight rebar anchorage of the stirrup is governing in the support region. This type of anchorage has a greater influence due to the lower anchorage capacity compared to the anchorage capacity of the hooked rebar. However, in both cases, the predicted shear capacity of the model exceeds the concrete shear capacity based on the RBK. Therefore, based on these results, it can be concluded that there is still a contribution of the non conforming stirrups to the total shear capacity.
The proposed model within this research could be used to predict the shear capacity of reinforced concrete beams with non-conforming stirrups. However, for more accurate results, it is recommended to further develop this model to overcome its current limitations. Additionally, it is recommended to conduct more experimental research on these types of beams, due to the limited amount found in literature. Finally, it should be taken into account that the model in this research uses a conservative assumption that the crack is perfectly aligned with the non-conforming stirrup.","Shear capacity; Non conforming stirrups; Reinforced concrete beams; Prestress; Layered approach; Modified compression field theory; Anchorage","en","master thesis","","","","","","","","","","","","Civil Engineering | Structural Engineering | Concrete Structures","",""
"uuid:657c365b-be9a-4a8d-b29d-6679fccec764","http://resolver.tudelft.nl/uuid:657c365b-be9a-4a8d-b29d-6679fccec764","How Might ChatGPT Improve the Accessibility of Quantum Computing?: A design research on improving Quantum Computing accessibility trough AI","D'Arcangelis, Costanza (TU Delft Industrial Design Engineering)","Lomas, J.D. (mentor); Nas, Deborah (mentor); Delft University of Technology (degree granting institution)","2024","The evolution of higher education and technological advancements has transformed the accessibility and understanding of complex subjects, such as quantum computing.
Traditionally, higher education has focused on specialized knowledge, making it challenging for individuals to explore diverse fields beyond their expertise. However, modern technologies have democratized access to information, enabling non-experts to engage with complex topics.
Quantum computing, grounded in the principles of quantum mechanics, is notoriously complex and has historically been accessible only to a select few. This exclusivity presents a challenge for those outside the field who wish to explore the possibilities of quantum technologies.
Recognizing this gap, the potential of ChatGPT to make quantum computing more approachable and understandable to non-experts can be explored. This exploration is not just about enhancing the functionality of ChatGPT but about envisioning a future where quantum computing is accessible to all, transforming the landscape of computation and innovation.
This research serves as an initial validation of the potential for large language models to act as an accessibility layer to quantum computing, having as a design tool the newly created Quantum Buddy 2.0, a custom GPT-4, fine-tuned through iterative feedback and testing.
A key part of the study is the development of a set of tasks designed to serve as benchmarks for evaluating the performance of large language models. Among these, one task was designed to enable those without a background in quantum mechanics to solve quantum encryption problems. Another task involved a test comparing Quantum Buddy in its previous versions with the standard model of ChatGPT. This comparison not only highlights the capabilities of these models but also provides insight for future evaluations. By utilizing these models, non-expert participants can now design and create with quantum computing, suggesting a future where quantum development moves forward rapidly.
The research thus demonstrates that ChatGPT significantly simplifies the process of programming quantum computers, facilitating learning and performance across a broad spectrum of abilities. It enables novices to engage in creative coding, allows coders to gain insights into quantum mechanics, and enhances the efficiency of quantum experts. This variety in application underscores ChatGPT’s role in democratizing access to quantum computing.
However, it is important to recognize that these findings represent the beginning of a much larger exploration. The evidence provided by the study points to a future where ChatGPT and similar large language models significantly enhance the non-expert's access to quantum computing. Despite the progress made, the journey is not without its challenges. The evolving capabilities of ChatGPT, along with the dynamic nature of programming languages and quantum computing itself, require ongoing adaptation and enhancement.
Overall, the research contributes to a foundational understanding of how large language models like ChatGPT can make quantum computing more accessible. This work lays the groundwork for further studies and developments, signaling a promising direction for the broader application and understanding of quantum computing technologies.","Quantum Computing; ChatGPT; Artificial Inteligence; Knowledge gap; accessibility","en","master thesis","","","","","","Quantum Buddy 2.0: https://chat.openai.com/g/g-HuukcppqT-quantum-buddy-2-0","","","","","","Design for Interaction","",""
"uuid:8ebbd0b5-5faa-4ebc-8697-f03d10317b9e","http://resolver.tudelft.nl/uuid:8ebbd0b5-5faa-4ebc-8697-f03d10317b9e","Energy transition at mixed business parks: A case study and guideline for consultants, government officials and entrepreneurs","Janissen, Jeroen (TU Delft Electrical Engineering, Mathematics and Computer Science)","Quist, J.N. (mentor); Fremouw, M.A. (graduation committee); van den Dobbelsteen, A.A.J.F. (graduation committee); Knigge, Joris (graduation committee); Delft University of Technology (degree granting institution)","2024","Climate change poses a significant threat to global lifestyles, necessitating urgent action to reduce greenhouse gas emissions (GHGs). The Netherlands, committed to the Paris Climate Agreement, faces the challenge of meeting ambitious emission reduction targets set by the European Union's Fit for 55 initiative. However, the integration of renewable energy sources, particularly solar photovoltaic (PV) and wind, and the electrification of industrial processes, strain the electricity grid, leading to grid congestion.
This thesis addresses the pressing question of designing and implementing renewable energy configurations in mixed business parks to increase renewable electricity usage and reduce grid congestion. Through a comprehensive approach, stakeholders are engaged, and a novel simulation tool combining Excel, Python, and EnergyPLAN is developed to evaluate various configurations.
Nine criteria, spanning economic, technological, social, and environmental aspects, are used to assess different configurations. A configuration featuring 6 MWp rooftop solar PV in an East/West orientation and 15% demand flexibility emerges as the optimal solution, significantly reducing grid congestion while providing economic benefits. Wind energy configurations coupled with solar PV achieve notable CO2 reduction but face integration challenges and higher costs.
Implications of integrating solar PV and flexibility extend to economic benefits, adaptation requirements, and exemplar roles for park stakeholders, governments, and Distribution System Operators (DSOs). Recommendations are provided for stakeholders involved in the energy transition, emphasizing collaboration, investment, and capacity building.
Future research should focus on including other energy and material flows on mixed business parks; a broader evaluation of the value proposition beyond direct economic benefits for the users on the park; and an in-depth analysis of the electricity balance using a detailed representation of the grid infrastructure.","Energy Transition; Energy Symbiosis; Mixed Business Parks; Grid Congestion; Renewable Energy Sources; Demand Response; Storage Modelling; MCDM; Stakeholder Analysis; Stakeholder Engagement; Case Study","en","master thesis","","","","","","","","","","","","Electrical Engineering | Sustainable Energy Technology","","52.93283,5.95107"
"uuid:d2edc481-9acd-41c3-877a-5ea0838d88c0","http://resolver.tudelft.nl/uuid:d2edc481-9acd-41c3-877a-5ea0838d88c0","An integrated modeling approach to provide flexibility and sustainability to the district heating system in South-Holland, the Netherlands","Colussi, Eva (TU Delft Technology, Policy and Management)","De Vries, Laurens (mentor); Okur, Ö. (graduation committee); Chauhan, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","In the European Union, heating and cooling account for 50% of the total energy consumption and half of the carbon emissions, as 75% of the energy is still supplied by fossil fuels. In the Netherlands, energy transition decision-makers are sailing in the dark in an attempt to realize the heat transition in high-density areas. How can market parties optimize the mix of heat supply technologies, while responding to policies and network requirements? To adequately manage renewable energy on a large scale, flexibility measures need to be in place across all components of the system, from generation to distribution, to supply and demand. This master thesis is part of the TU Delft research project ""DEMOSES"" and is done in collaboration with the energy company Eneco. The project aims to study to what extent the integration of heat storage and additional heat sources can enhance the flexibility and long-term sustainability of the South-Holland district heating network. This is done by developing and analyzing a district heating network model of South-Holland, and expanding the network with additional heat sources and heat storage. Additional heat sources lead to increased flexibility and sustainability, while additional heat storage primarily increases only the flexibility. Looking ahead to 2030, to realize the heat transition in South-Holland, many additional sources and storage should be added in the following years to realize a flexible, sustainable, and affordable district heating network. However, with the proposal of the Collective Heat System Act, the question is whether investments in additional heat sources and storage are attractive for energy companies when ownership of these assets in the following years cannot be guaranteed.","","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:1c209393-9f57-4857-9bcd-f75c4f725558","http://resolver.tudelft.nl/uuid:1c209393-9f57-4857-9bcd-f75c4f725558","On the Modelling of the Feeds for Integrated Lens Antennas","Tadolini, Cesare (TU Delft Electrical Engineering, Mathematics and Computer Science)","Neto, A. (mentor); Cavallo, D. (graduation committee); Spirito, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","The analysis of integrated front ends operated in the high-frequency regimes is addressed in this work. The analysis of these problems has been a critical bottleneck for decades due to the difficulties arising in adopting full-wave techniques. Assuming, as typical at lower frequencies, that the structures are planar leads to the inaccurate representation of some characteristic reactive behaviors. As a case in point, the characteristic impedance of transmission lines, whose thickness is comparable to the width, is not well represented by planar tools. Moreover, existing analytic formulas based on quasi-static approximations for the surrounding fields typically fail when the dynamic components of the fields are also affected by the stratifications. In this thesis, planar stratified media with transmission lines and radiators are considered to be part of the front end, with this latter being integrated (or in package) thanks to the systematic presence of a dielectric lens antenna.","Lens antennas; method of moments; Spectral Domain Methods; integrated antennas","en","master thesis","","","","","","","","2026-02-28","","","","Electrical Engineering","",""
"uuid:9f49b75a-d4f3-47ad-bf4a-4d75c2333ce6","http://resolver.tudelft.nl/uuid:9f49b75a-d4f3-47ad-bf4a-4d75c2333ce6","Design of a Water Capturing System for Thermal Extraction of Water on the Moon: In the context of In-Situ Resource Utilisation (ISRU)","Kalis, Chris (TU Delft Aerospace Engineering)","Menicucci, A. (mentor); Kiewiet, Luca (mentor); Delft University of Technology (degree granting institution)","2024","In-Situ Resource Utilisation (ISRU) is gaining prominence in space exploration due to its potential to reduce the number of costly launches from Earth. Among these resources, water holds significant importance for future space endeavours, thanks to its multiple applications e.g. as potable water, for harvesting crops, and as fuel after electrolysis to hydrogen and oxygen. While prior research has concentrated predominantly on the extraction of water from regolith, there has been a notable gap in exploring methods for capturing and liquefying the extracted water vapour. Therefore, initial concepts are presented and three experiments are executed. This resulted in a design proposal for the LUWEX experiment at the German Aerospace Center (DLR). LUWEX is an acronym for Validation of Lunar Water Extraction and Purification Technologies for In-Situ Propellant and Consumables Production. In particular, the amount of water extracted is planned to be higher compared to other publicly available experiments.","","en","master thesis","","","","","","","","2026-02-28","","","","Aerospace Engineering","",""
"uuid:6d1a6103-d2db-4137-b0b0-98f1fd4727a6","http://resolver.tudelft.nl/uuid:6d1a6103-d2db-4137-b0b0-98f1fd4727a6","Advancing WEEE Management in the Automotive Industry: The Application of the International Data Space for Improved Information Sharing","Aardse, Angel (TU Delft Technology, Policy and Management)","Ubacht, J. (mentor); Bharosa, Nitesh (graduation committee); Kamp, L.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis examines the pressing environmental issue stemming from the accumulation of Waste Electrical and Electronic Equipment (WEEE), particularly within the automotive sector. Despite directives from the European Commission aiming to promote a circular economy, challenges persist in effectively managing WEEE, particularly in End-of-Life Vehicles (ELVs). Current dismantling practices often lead to the loss of valuable materials, exacerbating environmental and health risks. Recognizing the need for improved data sharing, this research investigates the potential of the International Data Spaces (IDS) initiative in enhancing WEEE management within the automotive industry, with a focus on ELV dismantling.
The primary research question centers on how IDS can facilitate WEEE information exchange between manufacturers and dismantlers within the automotive sector. The study is structured into five phases to comprehensively address this question:
Exploratory Phase: This phase identifies current barriers to WEEE information sharing in the automotive industry, employing the Circular Economy (CE) monitoring framework for analysis.
Requirements Elicitation Phase: Through desk research, legislative analysis, and stakeholder interviews, essential requirements for effective information sharing are identified, considering barriers, legislative mandates, and dismantlers' perspectives.
Application Phase: The feasibility of meeting identified requirements using IDS is explored, drawing on academic literature and documentation from the IDS initiative.
Concluding Phase: Findings from previous stages are integrated to address the main research question regarding IDS's role in facilitating WEEE information sharing.
Discussion Phase: The final phase evaluates the research approach, discusses conclusions, limitations, and suggests avenues for future research.
Barriers to WEEE information sharing within the automotive industry encompass incomplete documentation, lack of harmonization, information gaps, inconsistent data entry, and restricted accessibility. These findings inform the elicitation of requirements, emphasizing the need for detailed dismantling information, interoperability, and user-friendly interfaces.
Evaluation of IDS demonstrates its potential in providing dismantlers access to fundamental information, simplifying data access processes, ensuring data sovereignty, facilitating interoperability, and supporting initiatives like the circularity vehicle passport. However, its effectiveness relies on stakeholder participation and regulatory support.
In conclusion, this thesis proposes IDS as a solution to enhance WEEE information sharing in the automotive industry, contributing to sustainable development and advancing scientific understanding. Further research is recommended to address implementation challenges and develop specific ontologies tailored to the automotive sector.","Critical Raw Materials; WEEE; Automotive Industry; End-of-life Vehicles; Circular economy (CE); Car Dismantlers","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:89edcb6a-6a0c-471d-be51-9d7be3aa23a3","http://resolver.tudelft.nl/uuid:89edcb6a-6a0c-471d-be51-9d7be3aa23a3","Unravelling night train travel behaviour: A stated preference survey into the influence of operational and personal factors","Weißhaar, Thaddäus (TU Delft Civil Engineering & Geosciences)","van Wee, G.P. (mentor); Molin, E.J.E. (mentor); van Oort, N. (mentor); Donners, Barth (mentor); Delft University of Technology (degree granting institution)","2024","Night trains benefit society in multiple ways. They are environmentally friendly, improve the accessibility of regions and are space-effective. Understanding traveller's preferences enables night train operators to improve night train services and harness societal benefits better. This study conducted a stated preference survey with 1031 respondents from the Netherlands to dive deeper into the importance of operational factors like booking convenience, travel costs, long travel times of up to 18 hours and accommodations. Additionally, factors that make up a convenient booking scenario were revealed. Lastly, a latent class choice model (LCCM) was applied to derive insights into heterogeneity and to determine to which extent personal factors influence class membership. Results reveal that for a convenient booking scenario, being able to book one ticket and comparing travel options are most important. However, booking convenience only plays a minor role in determining night train mode choice. Travel costs and accommodation are significantly more important. Several classes have been revealed: Environmentally conscious comfort lovers make up 13% of the respondents, experienced night train travellers 29\%, cost-sensitive travellers 37% and flight lovers 20%. Applying a scenario analysis, night train market shares vary from 20% to 71%, with significant heterogeneity among respondents. For practitioners, this implies focusing mainly on prices and accommodation while taking the significantly different preferences of the population into consideration.","night trains; Stated Preference Experiment; Panel Mixed Logit model; Panel Latent Class Choice Model; booking convenience","en","master thesis","","","","","","","","","","","","Transport, Infrastructure and Logistics","",""
"uuid:1ecb656a-c237-456b-bd86-9cd87f1ea5a5","http://resolver.tudelft.nl/uuid:1ecb656a-c237-456b-bd86-9cd87f1ea5a5","Additive Manufactured Branched Column Connection","Leban, Tilen (TU Delft Civil Engineering & Geosciences)","Louter, P.C. (mentor); Tankova, T. (mentor); Hermans, M.J.M. (mentor); Delft University of Technology (degree granting institution)","2024","An investigation into the application of additive manufacturing to the production of structural joints was conducted for this thesis. The main goal was to determine all necessary aspects that someone needs to consider when designing a structural part that is intended to be printed with additive manufacturing. As an example, the branched column connection was selected due to its inherent limitations, which can be effectively addressed through the integration of additive manufacturing techniques.
Within the construction realm, wire arc additive manufacturing (WAAM) stands out as particularly advantageous due to its ability to yield high mechanical properties comparable to conventionally manufactured materials, coupled with a high deposition rate. As with any manufacturing process, WAAM operates within certain constraints dictating the types of objects feasible for production.
To ensure compatibility with WAAM while achieving desired structural and aesthetic benchmarks, three laboratory tests were conducted. These tests scrutinized the impact of input process parameters, overhang, and overlapping on the quality of the build. Factors such as travel speed, wire feed speed, voltage, and current were examined for their influence on welding bead dimensions and quality. Additionally, an investigation into how the percentage of overlap affected print quality was done. Among the constraints, the most pivotal one was the overhang limitation, determining the minimum allowed overhang angle in perpendicular and parallel directions depending on the direction of the print.
The primary objective in designing the connection was to reduce the necessary material for the branched column connection’s manufacture. Topology optimization (TO) played a crucial role in achieving this goal. Various models were constructed, each differing in TO input parameters to find the model with the lowest required mass while maintaining adequate structural performance. These models varied based on TO objectives (equivalent von Mises stress, compliance, mass, and volume) and TO constraints (either mass retain percentage or maximum stress), while also integrating manufacturing constraints obtained from lab tests. Ultimately, the model that offered the lowest mass and satisfactory structural performance focused on compliance as its objective, while retaining 15% of its initial mass.
Based on the above explained research a design guideline could be proposed and includes all necessary steps and considerations that someone needs to take into account when designing a connection manufactured with WAAM. The steps of the guideline include: 1. Selection of additive manufacturing process; 2. Material selection; 3. Determination of additive manufacturing process manufacturing limitations; 4. Design phase including TO with the proposed input parameters.
In illustrating the advantages and limitations of WAAM in the construction industry and proposed design guideline, a case study involving a comparative analysis between a steel plate and a WAAM branch column connection was done. This study centered on the real life project, 6 Bevis Marks in London. The findings showcased a notable reduction in the required material. However, the limitations of this approach were apparent in the increased manufacturing time and costs.","Additive Manufacturing; Wire and arc Additive Manufacturing; WAAM; Topology Optimisation; Branched Columns","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:5260bec4-70f4-4428-b5db-3c431e6b3e8c","http://resolver.tudelft.nl/uuid:5260bec4-70f4-4428-b5db-3c431e6b3e8c","Infragravity Wave Motions in the Scheldt Region","Grandiek, Teun (TU Delft Civil Engineering & Geosciences)","Reniers, A.J.H.M. (mentor); Tissier, M.F.S. (graduation committee); Hofland, Bas (graduation committee); Akrish, G. (graduation committee); Slomp, Robert (mentor); Delft University of Technology (degree granting institution)","2024","This study focuses on the infragravity (IG) waves at 5 measurement sites (Brouwershavense Gat 2 (BG2), Oosterschelde 4 (OS4), Cadzand, Hansweert and Bath) in the Scheldt region, examining their characteristics in these waters as well as to what extent they can be modelled using SWAN (Simulating WAves Nearshore). To facilitate this, data collected during the occurrence of four storms (Corrie, Dudley, Eunice and Franklin) that traversed the North Sea in January and February 2022 has been used.
A spectral analysis has been used to provide insight into the IG and sea-swell (SS) wave field. To this extent, the significant wave height for the IG (0.005 – 0.04 Hz) and SS (0.04 – 0.33 Hz) frequency bands have been derived, in addition to the storm averaged wave period. Measurement device BG2 documented the largest storm averaged significant wave height for both the IG and SS frequency bands (0.256 m and 3.46 m during storm Corrie, respectively). The measurement device with the smallest storm averaged significant waveheight values was Hansweert, which measured 0.024 m and 0.217 m for the IG and SS wave frequencies, also during storm Corrie. Most of the wave energy for the measurement devices in the Western Scheldt, Hansweert and Bath, can be attributed to waves with frequency values larger than the upper boundary for SS waves (T < 3 s). The fraction of the total wave energy contained within the IG and SS frequency bands ranged from 0.1 to 0.56 for these two measurement devices. Conversely, the IG and SS frequency bands contain 0.81 to 0.96 of the total wave energy for measurement device Cadzand, BG2 and OS4. The correlation between the IG and SS significant wave heights is mostly strong for the BG2, OS4 and Cadzand measurement devices (0.657 to 0.956) and generally moderate for Hansweert and Bath (0.474 to 0.87), with one outlier equivalent to 0.128). A bispectral analysis was used to offer more insight regarding the components contributing to the total IG wave field. The results at Bath proved to be erroneous for all storms except Corrie, as the derived free IG (FIG) contribution was negative. The origin remains unclear, although it appears to be related to unexplained spurious bursts in the wave elevation signal. The bispectral analysis for the remainder of the locations lead to maximum TIG wave heights ranging from 0.05 m to 0.12 m for Hansweert, 0.15 m to 0.39 m for BG2, 0.11 m to 0.35 m for OS4 and 0.21 m to 0.34 m for Cadzand for the 4 storms. The contribution of the bound IG (BIG) and FIG energy at Bath and Hansweert appears to fluctuate heavily, undergoing rapid changes on an hourly basis. For BG2, OS4 and Cadzand, the FIG energy contribution is strongly dominant as it generally amounted to > 0.75 of the TIG energy.
The capabilities of the SWAN model were evaluated by simulating FIG waves in the North Sea basin. The model relates incident SS wave energy to reflected FIG wave energy with FIG source lines based on the reflection parametrization of Ardhuin et al. (2014). The hourly SS wave inputs were provided by Copernicus Marine Service. The predictive skill was used to qualitatively assess to what extent the model is able to reproduce FIG waves in the Scheldt region. The model was unable to correctly predict the FIG waves Hansweert and Bath, where the predictive skill values for all storms ranged from 0.0003 to 0.0009 for Hansweert, and were 0 for Bath. Better predictive skill values were obtained for BG2 (0.5044 to 0.6565), OS4 (0.3327 to 0.4293) and Cadzand (0.6466 to 0.7510), but there is still room for improvement. The lacking skill values can be attributed to not enough FIG wave energy being able to penetrate the estuarine waters. Reflective lines were implemented along the coastline of the Western Scheldt in an attempt to force more FIG energy into the estuary. This only led to a minor increase for the predictive skill values (O(0.002) for Hansweert, 0 for Bath and O(0.0001) for BG2, OS4 and Cadzand) but from a spatial standpoint, it appears that there are locations in the estuary where the absolute increase was O(0.02), which is significant as there are areas in the estuary where the significant FIG wave height has doubled as a consequence of the implementation of the reflective lines.
systems and other active components which all require battery power. In order to save some of this battery power, reduce weight, and have the devices have a longer runtime, a form of energy regeneration is desired. Therefore the goal of
this study is to design and experimentally evaluate an energy harvesting system to power the control system of lower limb prostheses. The final prototype is designed following the process of setting up functional requirements, constraints and wishes. This leads to three derived concepts. After an evaluation against performance criteria and an in-depth evaluation concerning the power output, the compliant spring design is chosen to be worked out further and evaluated with a newly designed vibration shaker table. The relevant findings are laid out in the results. From these findings, interpretations and implications are discussed further, concerning advantages and limitations of the energy harvesters and the experiment. Results from the conducted experiment show a peak power output of 25.8 mW at an input amplitude of 12 mm and a frequency of 9 Hz. A power mass ratio of 0.21W/kg is achieved. The design meets the power demand requirements to power microprocessors and sensors of the control system of a lower limb prosthesis and extends runtime with 15.7%. However it is still important to investigate the power requirements for state of the art lower limb prostheses. Furthermore, it is recommended to improve overall efficiency in future studies, compare the results with state of the art energy harvesters based on vibrations, and execute a gait test for further design validation. The results from this study demonstrate comparable data and present the innovations possible in prosthesis design and the advancements in utilizing ambient power sources for energy harvesting. Enhancing the overall efficiency of this design, and promoting comparable results to other designs in the existing literature, could emphasize on the potential of energy harvesting applications.","Lower limb prostheses; Prosthetic device; Energy harvesting; Vibration energy; Vibration energy harvesting; Biomechanical energy harvesting","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:e15c2fb5-f022-421b-a581-720844755949","http://resolver.tudelft.nl/uuid:e15c2fb5-f022-421b-a581-720844755949","Computing implied volatility using quantum neural network","Yuan, Zibo (TU Delft Electrical Engineering, Mathematics and Computer Science)","Liu, S. (mentor); Vuik, Cornelis (mentor); Delft University of Technology (degree granting institution)","2024","Implied volatility is critical in financial markets, especially for option pricing. Traditional methods for its calculation sometimes are not well suited to some scenarios. Recent developments in neural networks have provided more efficient alternatives.
Leveraging advances in quantum computing, our research introduces quantum neural networks for computing implied volatility, assessing the feasibility and characteristics of this novel approach. We focus on two quantum neural network architectures: Dissipative Quantum Neural Networks (DQNN) and Parameterized Variational Quantum Circuits (PVQNN). DQNN, similar to classical neural networks in structure and training ease, faces challenges with quantum state outputs and data decoding, impacting performance negatively. Besides, limited by the reliance on network output states at each layer, DQNN faces challenges in implementation with the current state of quantum hardware.
In contrast, PVQNN offers a more promising solution. Compared to DQNN, PVQNN requires fewer qubits, can apply traditional optimizers to train the model, and can run on NISQ devices. This research thoroughly examines various aspects influencing PVQNN's performance, including training data characteristics, data re-uploading technology, network size, data encoding methods, and quantum circuit design. The selected PVQNN model can achieve high accuracy in implied volatility computation with $R^2$ of approximately 0.999. In addition, we find that the PVQNN can obtain satisfactory results even with limited training data, setting it apart from traditional neural networks.
This thesis not only adopts a new model to compute implied volatility but also deepens the understanding of quantum neural networks in financial modeling. However, due to resource constraints, our experiments are conducted in simulations on traditional computers, and thus our study focuses mainly on the expressive power of QNNs rather than their operational efficiency.","Quantum neural network; Implied volatility","en","master thesis","","","","","","code: https://github.com/eddie7373/QNN","","","","","","Applied Mathematics | Computational Science and Engineering","",""
"uuid:c5720b7e-1828-4948-a76a-89a6361b3e03","http://resolver.tudelft.nl/uuid:c5720b7e-1828-4948-a76a-89a6361b3e03","Delft Measures Rain: A quality assessment of precipitation measurements from personal weather stations","Boonstra, Marchien (TU Delft Civil Engineering & Geosciences)","Droste, A.M. (mentor); ten Veldhuis, Marie-claire (graduation committee); Schleiss, M.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Personal weather station (PWS) networks have the potential to supply precipitation data at high spatial and temporal resolution for urban hydrological modeling. Past research has shown promising results on the quality of PWS data, for example from Netatmo gauges, but studies on other PWS brands are limited. This thesis assesses the quality of precipitation measurements from the Alecto WS-5500 personal weather station. During a controlled experimental setup in an urban environment, the Alecto was found to overestimate rainfall due to incomplete emptying of the tipping bucket. Correcting this mechanical error by a 10 percent reduction factor lowered the relative bias to 0.00 or 0.06, when comparing the station to official KNMI gauge or KNMI gauge-adjusted radar, respectively. Correlations were high between stations with non-faulty setups, but at the 5 minute resolution, correlations were substantially lowered by sampling errors caused during the data transfer to PWS data platforms. A quality control method from de Vos et al. (2019) was adapted and applied to data from a citizen science project in Delft, the Netherlands, which had a 12-month period of measurements for 20 stations, and a 3-month period of measurements from 40 stations. The filtering of faulty zero measurements was improved by applying the filter on hourly accumulations, and the bias correction was stabilized. The variation over individual PWSs, however, remained high due to setup differences. The complex installation process for citizens and issues with software and data accessibility are limiting factors and warrant further research to improve the usability of PWS data for urban hydrological applications.","Citizen science; Personal weather stations; Precipitation; the Green Village; Crowdsourced data; Alecto WS-5500; Delft Meet; Delft Meet Regen","en","master thesis","","","","","","","","","","","","Water Management","Delft Meet Regen","51.99653766537575, 4.377590541793161"
"uuid:cb064764-3b7b-4fb2-b95c-aeb31523ce06","http://resolver.tudelft.nl/uuid:cb064764-3b7b-4fb2-b95c-aeb31523ce06","Footprint for the Future, Exploring Bio-Based Biodegradable Plastics in Trail Running Shoes","Balboni, Matteo (TU Delft Industrial Design Engineering)","Bakker, C.A. (mentor); Bos, P. (mentor); Delft University of Technology (degree granting institution)","2024","This research project explores the environmental issue of microplastic pollution, specifically focusing on its release from shoe soles into natural ecosystems. Despite increasing global awareness of microplastics, the particular impact of footwear, especially those used for outdoor activities in natural areas like trail running, has been largely overlooked. Microplastics released in these settings can directly impact ecosystems, affecting wildlife and soil health. This study investigates the potential of bio-based, biodegradable plastics, which can decompose harmlessly in soil, as an alternative material for trail running shoe soles. The aim is to mitigate harmful microplastic pollution and explore how the design of trail running shoes can be adapted to incorporate bio-based, biodegradable plastics.
The project begins by examining the problem of microplastic pollution, its origins, consequences, and the role of footwear. It distinguishes the difference between bio-based and petroleum-based plastics and the role of bio-based biodegradable and compostable plastics in embracing a circular economy. Through exploratory research, design iterations, prototyping, and critical analysis, this study evaluates the feasibility of using bio-based, biodegradable plastics in manufacturing trail running shoe soles. In fact, shoe soles have been identified as the primary source of microplastic pollution due to the constant abrasion with the ground.
A research was conducted in order to identify a bio-based soil-biodegradable plastic which could replace the currently used synthetic rubber. In terms of performance and environmental sustainability, PHA stands as the closest in meeting these criteria, yet it is not fully suitable for shoe soles application due to its limited flexibility.
Nevertheless, the project conceptualises “BioStep”, a trail running shoe that features a replaceable biodegradable outsole. The usage of such an outsole does not release any harmful microplastic when used during outdoor activities or in the decomposition process at the end of its lifespan.
This project sets the basis for the development of bio-based soil-biodegradable shoe soles for trail running shoes. Further research will be needed to identify a ready-to-use material and to address its performance in running scenarios.
Finally, this study emphasizes the need for collaborative efforts among designers, manufacturers, and material scientists to mitigate microplastic pollution and to set the path towards more sustainable footwear.","Microplastics; Bio-based plastic; Biodegradable plastic; Footwear; Shoe soles","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:6301b022-df21-4fbe-aac6-db5f9bfa5e5b","http://resolver.tudelft.nl/uuid:6301b022-df21-4fbe-aac6-db5f9bfa5e5b","Rethinking Youth Participation in Policymaking: A Frame Innovation Approach","Osinga, Susanna (TU Delft Industrial Design Engineering)","Gonçalves, M. (mentor); van der Bijl-Brouwer, M. (mentor); Delft University of Technology (degree granting institution)","2024","Youth participation is becoming increasingly important in municipal governance. However, despite the introduction of new tools, podcasts, and events designed to foster participation, engaging young voices in policy-making remains a challenge. This project explores whether a different perspective on this challenge can lead to more meaningful engagement.
This project is part of Healthy Start, a collaborative initiative between the Delft University of Technology, Erasmus Medisch Centrum and the Erasmus University Rotterdam, which seeks to enhance the well-being of young individuals. Among its ambitions is the enhancement of youth participation. The project will emphasize youth participation in municipal policy in Rotterdam.
Using the Frame Innovation method, a design approach focused on redefining problems to uncover innovative solutions, this study aims to discover unique insights by ‘reframing’ the issue of youth participation. Achieving an understanding of the stakeholders and their values was accomplished through a Research through Design approach. A variety of design activities were undertaken, including engaging policy advisors in creative sessions at Het Timmerhuis, and deploying cultural probes during dialogues with young individuals in a sounding board group and at the Rotterdam Blaak library.
The findings reveal that stakeholders have diverse needs. Not all officials view participation the same way, and differences among young people are significant. Four main themes emerged, reflecting the values of these diverse groups:
Open Hearts, Open Minds: This theme underscores the importance of genuine interactions and empathy, highlighting how prejudices can complicate matters. For example, officials may fear being perceived negatively by the public, while young people worry about being seen as inexperienced.
Navigating the Unknown: Participatory processes involve uncertainties, requiring both youths and officials to venture into unfamiliar territory. This theme explores how they can feel in control despite these uncertainties.
Driven by Responsibility: This focuses on the sense of duty and how it affects engagement. It questions when stakeholders consider something important enough to warrant their involvement.
What You Do Matters: This theme emphasizes the significance of feeling that one’s contributions are impactful and explores the dynamics of power within participation. Both youths and officials can feel powerless, doubting the impact of their efforts and not seeing the success of their actions.
Reframing the problem based on these themes offers new perspectives on addressing the challenges of youth participation. Navigating the Unknown might suggest a future with a municipal “travel agency” for participation, providing guidance, resources, and connections to make the participatory process less daunting and more accessible. Or adopting an “open hearts, open minds” approach one could imagine facilitating transparent discussions about roles and aspirations, enhancing engagement and ensuring participation leads to meaningful outcomes.
This report proposes new strategic approaches to youth participation in Rotterdam’s policymaking. By gaining a deeper understanding of the problem space and reframing it, these new perspectives offer avenues for further exploration. Insights into the frame innovation methodology are also shared to inform future studies.
Four affected physical properties were determined through literature research: blood flow, blood pressure, skin resistance, and skin temperature. Of these properties, skin temperature was found to be the most promising based on a literature study, as it seemed to be both easily measurable and relatively independent of other bodily functions. Then the constraints of healthcare in low-income countries were examined and devices that work within these constraints were identified. Of these, the infrared camera showed the most promise, because of its ease of use and cost to accuracy ratio.
A single-subject study was performed to test the restorative capacity of the autonomous system by deliberately changing the temperature of the hand with a heating and cooling agent. Four locations were used on both hands, and both palmar and dorsal side of the hand, using different doses of the agents. The temperature change of the skin was measured using an InfraRed (IR) camera.
A large variation in results was found, but the results did show some evidence for structural differences in the temperature normalization between the affected and unaffected hand. The palmar side shows a stronger reaction than the dorsal side. The cooling agent seems to be more effective, but there are some caveats attached to its use. An interesting observation is that the most noticeable difference between left and right was measured in an area of low circulation. This gives some indication that this area has the most difficulty with returning to the neutral state.
Conclusion: This research shows that skin temperature variation as a result of applying heating or cooling agents to the skin can be measured using an infrared camera, suggesting that minor variations in skin temperature as a result of neuropathy can also be measured, further research with more test subjects should be done.","Leprosy; Neuropathy; Infrared Camera; Temperature; Detection","en","master thesis","","","","","","","","","","","","Biomedical Engineering","",""
"uuid:09a0ef1d-9c35-4817-b515-e025a9ab837f","http://resolver.tudelft.nl/uuid:09a0ef1d-9c35-4817-b515-e025a9ab837f","Design for Togetherness at Home: Integrating Technology to Bond Children and Grandparents Through Shared Experiences","Xu, Hongxin (TU Delft Industrial Design Engineering)","van der Vegte, Wilhelm Frederik (mentor); Gielen, M.A. (mentor); Delft University of Technology (degree granting institution)","2024","Strong intergenerational relationships can provide emotional support and stability for both grandparents and grandchildren. Technology tools have been proven to be beneficial in connecting grandchildren and grandparents. Prior work mainly examined how to use technology to connect children and their grandparents over a distance. Those collocated grandparents and grandchildren who keep regular physical contact are often neglected in the research.It is essential to understand technology’s potential in bonding them in physical meet ups considering the trending of multigenerational families.
This graduation project aims to foster connectedness between children aged 8 to 12 and their collocated grandparents in the Netherlands through physical interactions. Adopting a holistic approach, we explored moments of togetherness, identifying desired qualities of these interactions and defining promising shared experiences for the future.
The research involves three phases of empirical investigations. This research begins by examining how technology could positively impact their bond. Using participatory cards during interviews, this phase captures participants' perspectives, employing mixed methods including sentiment analysis, group clustering, and thematic coding to identify key elements in shared activities that promote or impede intergenerational connectivity. This analysis informs a framework to guide the development of technology aimed at supporting connectivity. Next, the second phase, insights from two design workshops are synthesized into a series of design concepts, which are then visualized through storyboards. The final phase involves evaluating these concepts by presenting the storyboards to both experts and child-grandparent pairs. This step is intended to refine our understanding of how these technological solutions can be leveraged to strengthen family bonds.","Intergenerational Relationships; Child-Grandparent Connection; Technology in Family Bonding; Design and Family Dynamics","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:01c0155a-7236-4cf2-bb92-89b5e56d8410","http://resolver.tudelft.nl/uuid:01c0155a-7236-4cf2-bb92-89b5e56d8410","Designing for Mindful Food Consumption: Enhancing Consumer Engagement to Reduce Food Delivery Waste","Jiang, SHIYUE (TU Delft Industrial Design Engineering)","Schifferstein, Hendrik N.J. (mentor); Miao, X. (mentor); Delft University of Technology (degree granting institution)","2024","In China, the takeaway industry has been steadily rising, gradually maturing, and evolving into a large-scale dining market. Urban white-collar consumers constitute the primary user base for food delivery and are the target user group for this project. However, food delivery waste has yet to be adequately addressed. During the theme exploration and research phases, through methods such as interviews and co-creation, it was found that subjectively, there is a weak awareness of reducing food waste, unclear criteria for judging the freshness of leftovers, and a lack of facilities for storage and reheating. However, the most significant objective obstacles include portion sizes exceeding appetite, and the taste not meeting consumer expectations.
This corresponds to an opportunity to bridge the information gap between consumers' expectations and the actual portion sizes and tastes of dishes. Combining with the SICAS consumer behavior model, which aims to increase the conversion rate of consumers' willingness to reduce food delivery waste into actual behavior. The goal of this project is to assist consumers in feeling confident, inspired, and encouraged about how to order takeout that suits their food intake and tastes, thereby reducing food waste. Through brainstorming sessions and prototype testing during the ideation phase, the final design was iterated in both intuitive and conscious directions.
The final design is a new takeout ordering app that primarily integrates an AI assistant - Order Pal, and visual information prompts to help consumers of different personas order takeout with appropriate portion sizes and flavors in various scenarios. Through Order Pal learning users' ordering preferences, recommending suitable portion sizes and flavors, the app assists consumers in quickly and conveniently placing takeout orders while feeling guided and inspired. Additional details in visual information continually prompt and reinforce consumers' understanding of portion sizes and flavors. With long-term reminders and encouragement from Order Pal, consumers gain a better understanding of their food preferences and intake, enabling them to find meals that suit them, reduce food waste, and cultivate a more mindful food consumption.","","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:109888a8-05de-4bb6-afd2-f5e7048a3ed9","http://resolver.tudelft.nl/uuid:109888a8-05de-4bb6-afd2-f5e7048a3ed9","Transfer-free Fabrication and Assessment of Transparent Multilayer CVD Graphene MEAs for in-vitro Optogenetic Studies","León González, Gonzalo (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Bio-Electronics)","Giagka, Vasiliki (mentor); Vollebregt, S. (mentor); Mastrangeli, Massimo (graduation committee); Accardo, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Electronic interfaces, particularly microelectrode arrays (MEAs), are crucial for studying electrophysiological processes in the body, with applications ranging from implants to deep brain simulators. In neuroscience, they play a vital role in exploring neuronal cell distribution and behaviour, as well as disorders like epilepsy and Alzheimer’s disease. However, electrophysiological recordings have limitations, that have led to the exploration of optical approaches like calcium imaging. To address the shortcomings, a promising strategy involves integrating electrophysiology and optical methods for simultaneous cellular activity measurement, capitalising on their combined temporal and spatial resolution. The challenge lies in developing fully transparent MEAs to overcome the limitations of traditional opaque electrodes.
Graphene’s versatile properties, spanning from electrical conductivity to mechanical flexibility, position it as an ideal material for transparent and flexible electronics, particularly in neural recording and stimulation. Due to these properties, graphene MEAs (gMEAs) allow integration with various optical techniques, overcoming limitations associated with traditional opaque MEAs.
In this project, we designed and fabricated a transparent gMEA, intended to perform electrical signal recordings and optical voltage mappings simultaneously from photostimulated optogenetic cell lines. The design allows for photostimulation from a source beneath the gMEA, while enabling unobstructed optical measurements from above. The electrodes were crafted from multilayer chemical vapour deposition (CVD) graphene, chosen for its transparency and favourable electrical properties. Quartz and sapphire were evaluated as potential substrates for the device. After demonstrating the synthesis of multilayer graphene was possible on both substrates, quartz was selected as the preferred material due to its resistance to graphene delamination.
Characterisation of the gMEAs was done using various techniques, including optical transmittance (OT), electrochemical impedance spectroscopy (EIS), and measurements of the signal-to-noise ratio (SNR). The stability of the gMEAs was also assessed by immersing the devices in cell culture medium and with ageing tests performed in PBS. Initial electrochemical characterisation of the gMEAs exhibited promising signal detection despite a relatively high baseline noise of ∼ 23 μV . In comparison, commercially available MultiChannel Systems MEA (60MEA200/30iR-Ti), showed a lower baseline noise (∼ 4 μV ), but gMEAs achieved comparable signal sensitivity. EIS of gMEAs revealed an impedance at 1 kHz ranging from 3.2 to 9.89 MΩ, largely surpassing values in other studies. However, when area normalised, the impedance remained comparable to reported values. Stability tests identified issues related to the permeability of the encapsulation layer and degradation of molybdenum structures, causing large variations in the SNR and EIS measurements after exposure to liquid media.","Graphene; Chemical Vapor Deposition (CVD); Microelectrode arrays; Optogenetic Compatibility","en","master thesis","","","","","","","","2025-02-28","","","","Biomedical Engineering","",""
"uuid:aee43460-d19f-47d3-925b-89802f5addfb","http://resolver.tudelft.nl/uuid:aee43460-d19f-47d3-925b-89802f5addfb","The erosion process of cohesive soil due to a submerged inclined water jet","Snyder, Andrew (TU Delft Mechanical, Maritime and Materials Engineering)","Alhaddad, S.M.S. (mentor); Keetels, G.H. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis investigates the erosion process of cohesive soil due to a submerged, moving, inclined water jet. This study provides a visualization and description of the failure mechanics of cohesive soil due to a submerged inclined water jet and develops a new equation for estimating the erosion process of cohesive soil while including the angle of the water jet as a parameter. Figures providing support to this new equation are also provided in Chapter 7. The primary variables tested are jetting angle, stand-off distance, forward velocity, and jetting velocity.
The study is guided by two primary research objectives. First, to visually and descriptively understand the failure mechanics of cohesive soil subjected to a submerged inclined water jet. Second, to develop a method of predicting the erosion process of cohesive soil, considering variable jet angles, stand-off distances, forward velocity, and jet velocity of a submerged inclined water jet.
Experimental testing was conducted in the ""Dredging Lab"" of Delft University of Technology. The experiment involved eroding cohesive soil blocks using half of a circular nozzle placed along the wall of a flume. This nozzle configuration allowed for the nozzle to be visible during testing. I designed several half nozzles that were tested in a flume provided by TU Delft. Nozzles with a variety of nozzle diameters were designed to have either a 25, 45, 65, 90, 115, 135, or 155 degree jetting angle. Seventy-two clay blocks with a known undrained shear strength were used as the cohesive test soil, allowing for immediate replacement after each test. Detailed experimental procedures are outlined in Section 5.3, offering insights into the design and execution of the tests.
The data analysis provides evidence that the jetting angle has a notable impact on the erosion process of cohesive soil. This includes a “deflecting jet” failure mode, the formation and prediction of the sediment plume, and the estimation of the erosion cavity depth. The failure mode of the soil can be seen in Section 5.5 and data analysis figures are provided in Chapter 6. Section 7.1.2 provides a new estimation for the erosion depth of cohesive soil using an inclined water jet (Equation 7.17). This study contributes to our understanding of cohesive soil erosion and methods of estimating erosion processes. The findings emphasize the crucial role of the jetting angle and provide a foundation for future research aimed at refining erosion prediction models and exploring additional parameters influencing the process. Practical applications may include improved design considerations for projects involving water jet erosion such as deep-sea mining, water injection dredging, trailing suction hopper dredgers, as well as other dredging processes involving water jetting.
transport (also referred to as sediment transport), a horizontal pipe is a conduit where particles suspended in a viscous fluid are transported. The dynamics of this transport are governed by several dimensionless numbers, each highlighting distinct aspects of
the flow. Prominently, in this work we explore the role of the Reynolds number (Re) which encapsulates the balance between inertial and viscous forces, the Galileo number (Ga) which characterizes the competition between inertial and viscous effects in particle settling under gravity, and concentration of particles which has an influence on particle-particle and particle-fluid interactions. Key flow dynamics that determine the behaviour of the flow include turbulent mixing, gravitational settling of particles, and shear-induced particle migration due to particle-stress gradients. Practical applications of slurry transport are numerous, spanning industries such as mining, agriculture, and chemical processing. Slurry transport is of particular relevance to the dredging industry in the Netherlands to maintain its inland waterways and for land reclamation projects. However, pipeline operators grapple with issues ranging from pressure drop and the prevention of bed formation to the control of excessive pipe abrasion, silting risks, and production instability. These challenges stem from the intricate interplay of particle behavior, fluid dynamics, and pipeline geometry....","sediment transport; slurry flow; transport regimes; flow transition; secondary flow; turbulence modulation; multiparticle interactions; dense suspensions; sedimentation; path instabilities; wake-trapping; drafting-kissing-tumbling; kinematic waves; direct numerical simulation; immersed boundary method; soft-sphere collision model; high-performance computing","en","doctoral thesis","","978-94-6496-054-9","","","","","","","","","Multi Phase Systems","","",""
"uuid:6f4faa7d-dc8e-490b-99cc-87af92ff57dd","http://resolver.tudelft.nl/uuid:6f4faa7d-dc8e-490b-99cc-87af92ff57dd","Choice modelling for planned special events: A study on improving accessibility of the AFAS AZ Stadium","Nijholt, Vincent (TU Delft Civil Engineering & Geosciences)","van Arem, B. (mentor); Daamen, W. (mentor); Sharif Azadeh, S. (mentor); de Boer, B. (mentor); Delft University of Technology (degree granting institution)","2024","This research provides insight into ways to increase accessibility for Planned Special Events (PSEs) via discrete choice modelling. A special focus within this study is put into the AFAS AZ Stadium in Alkmaar. During the events held at the AFAS AZ Stadium disturbances are experienced by its visitors with regard to crowding levels and access/egress times. Quantifying the traffic volume on the infrastructure around the venue is done via revealed preference methods. Cyclists are counted via pneumatic tubes. Whereas pedestrians are measured via radio-wave sensors. To find ways to mitigate these problems, interviews are held with organisers of similar PSEs within The Netherlands.
To find the effectiveness of the obtained accessibility measures a stated preference study is held. From this study it is obtained that the transportation mode habit that one has is a key factor within the mode choice. Besides the effect on accessibility additional decision factors are discussed to find the best measure which can be applied best at the AFAS AZ Stadium. Based on the decision factors and the performance of the accessibility measures a total of six effective measures are determined.","MNL; Planned Special Events; Stadium; Choice modelling; Survey; Expert interviews; Stated preference","en","master thesis","","","","","","","","","","","","Civil Engineering | Transport and Planning","",""
"uuid:f68ed06f-0c16-46a3-9004-ecaffb18611b","http://resolver.tudelft.nl/uuid:f68ed06f-0c16-46a3-9004-ecaffb18611b","Fabrication and characterisation of autoparametric resonators","Wansink, Nick (TU Delft Mechanical Engineering)","Alijani, F. (mentor); Farhadi Machekposhti, D. (mentor); Li, Z. (graduation committee); Hunt, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Micromechanical resonators, which have become feasible due to advanced manufacturing techniques, have shown several interesting phenomena including mode coupling in a range of applications that span metrology and sensing. Conventional fabrication methods of these resonators have been used throughout the field. However, fabrication of micromechanical resonators by femtosecond laser ablation which could accelerate prototyping, access to three dimensional resonators and reduce clean room use, has received little attention.
In this study, a protocol for fabricating and measuring laser cut micromechanical resonators using computational analysis and experimental techniques has been developed and validated through comparison with previous works by characterising doubly clamped beam resonators. The fabricated prototype is demonstrated to exhibit autoparametric resonance and coupling showcasing the potential of the new approach in engineering and fast prototyping of coupled micromechanical resonators.","laser Doppler vibrometer; femtosecond laser vaporization; femtosecond laser ablation; autoparametric coupling; mode coupling; internal resonance; micromechanical resonator; geometric nonlinearity","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Micro and Nano Engineering (MNE)","",""
"uuid:d825e9cc-d4c6-4a2a-bf15-16bd16e6570c","http://resolver.tudelft.nl/uuid:d825e9cc-d4c6-4a2a-bf15-16bd16e6570c","Optimizing Nanomechanical Resonators","Algra, Hendrik Jaap (TU Delft Mechanical, Maritime and Materials Engineering)","Alijani, F. (mentor); Li, Z. (mentor); Aragon, A.M. (mentor); Delft University of Technology (degree granting institution)","2024","The predominant influence of geometry and tensile stress on the Q factor of nanomechanical resonators is a phenomenon commonly described as dissipation dilution. In recent years, a variety of studies has looked into maximizing this effect, resulting in an assortment of softly-clamped resonator designs. This paper proposes a methodology that uses topology optimization (TO) to design nanomechanical structures with very high Q factors, by maximizing the effects of dissipation dilution. A novel equation, based on the tensile and bending energies of a prestressed finite element model, is proposed to capture this effect. Through adjoint sensitivity analysis, the sensitivity of this function with respect to (changes in) element-level design parameters was determined, which is a capability that is not available in commercial finite element packages. Furthermore, the absence of information required a priori to the optimization makes the proposed methodology versatile and easy to use. After verification of the equation and its sensitivity, it is used as an objective in TO to optimize resonator geometries inspired by state-of-the-art resonator designs. Given a thickness of 340nm and prestress of 1GPa, the final designs show a numerical Q × f0 that competes with optimized designs found in literature.","Topology optimization; Dissipation dilution; Q factor; Adjoint problem","en","master thesis","","","","","","","","2026-03-01","","","","Mechanical Engineering","",""
"uuid:a6e380df-aded-4f0d-b78d-8d8568d458d1","http://resolver.tudelft.nl/uuid:a6e380df-aded-4f0d-b78d-8d8568d458d1","Exploring how the public’s voice can be more effectively incorporated in the front-end of a project: The Museumpark case","Frangu, Alesia (TU Delft Civil Engineering & Geosciences)","Ninan, Dr Johan (mentor); Esteban, T.A.O.E. (mentor); Elmohr, S.E.M.A. (mentor); Delft University of Technology (degree granting institution)","2024","Infrastructure and urban development projects continue to experience problems and tensions when it comes to external stakeholders, even though the importance of collaboration and dialogue between the external stakeholders and project developers is being increasingly stressed. There seems to be a lack of supporting policy and management strategies for better involvement of the public in public projects and confusion and uncertainty from the project developers’ side on how to engage with them in a more constructive way.
This research looks into how the public’s voice can be more adequately incorporated in public projects in the front-end, where the course the project will follow is set, and its values and relationships with stakeholders defined, in order to improve the collaboration between public governing bodies and their citizens. It does so by analysing an example of public projects with unsuccessful public participation that resulted in conflict: the Museumpark case, where the municipality of Rotterdam decided to make changes to the previous large asphalted square in-between Rotterdam’s most known museums by following standard greening designs. The issue was that this square was one of the most popular skating spots in the city with a growing community. Different disciplines that fall under the skating umbrella could be seen in the square, the main ones being skateboarding, longboarding and rollerskating. Besides these, other urban sports and styles were part of the scene, such as freestyle dancers, hoola-hoopers, and so on. Unbeknownst to the community, the redevelopment plans were progressing, and they only found out about the changes that would happen when the decision was finalised. Because the decision-making was done without consulting the skaters, this led to resistance from them, council debates, a delayed project, and growing distrust about the municipality from the community.
The aim of this research is to to understand current issues commonly faced in projects in the public sector in management, communication and stakeholder participation design, and to highlight strategies to improve public engagement in public projects.
The result of the research is a conceptual framework with strategies derived from the prevailing issues found in literature and what went wrong in practice (as seen in the empirical case). Novel participation methods and alternative approaches for external stakeholder engagement in culturally sensitive projects are needed more in practice in order to reduce the risk of problems occurring in projects or resistance. By testing these strategies in practice, a push is made towards a more inclusive participation, better communication between project developers and the public or the governmental body and the public, more inclusion of social values in projects, higher transparency and authenticity, and implementation of innovative ideas that come from the public’s knowledge.","Public participation; Public projects; Collective action; External stakeholders; Social value","en","master thesis","","","","","","","","","","","","Construction Management and Engineering","","51.914264, 4.471730"
"uuid:a79b4861-1fba-47bb-a925-19726339d751","http://resolver.tudelft.nl/uuid:a79b4861-1fba-47bb-a925-19726339d751","Operational Impact of Ammonia as Marine Fuel: A MILP model for an Ammonia-Powered Shipping Network","Boersma, Femke (TU Delft Mechanical, Maritime and Materials Engineering)","Pruyn, J.F.J. (mentor); Naghash, H. (mentor); van Hassel, E.B.H.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","The consequences of climate change are becoming more and more visible. A significant cause of this is CO2 emissions; the shipping sector is responsible for 3% of global CO2 emissions. As a result, the Fourth IMO GHG Study 2020 presents pathways to reduce the GHG emission of the shipping industry by 50% by 2050. Recent IMO goals have overtaken this to reduce net emissions to zero by that year.
As a result, research in renewable energy sources has grown in significant interest, offering a wide range of potential solutions. Recently, (green) ammonia (NH3) has been added to these pools, as it is carbon-free and has a higher storage density than liquid or pressurized hydrogen. However, when comparing ammonia to the current conservative fuels, its energy density is still not at the same level, and more fuel volume would be required to deliver the same amount of energy. There are two ways to address this challenge. More frequent bunkering or larger volumes for the fuel tanks on board at the cost of cargo space and thus income. This is a difficult choice to make in the pre-design as it depends on the choices of other owners as well.
This report investigates the impact of a fuel switch to ammonia on the ship design and bunkering pattern based on the current operational profile of 1025 seagoing ships. A mixed integer linear programming model will establish the optimal fuel tank volume and bunkering strategy for each vessel. This model considers rerouting for trips that are not feasible and two approaches for the bunker strategy. Besides, a port model will establish the ammonia bunker pricing based on the resulting demand in each port. The estimated ammonia bunker prices are implemented in the bunker strategy model. This is repeated till a balance is found. The two models represent an Ammonia Powered Shipping Network considering a homogeneous shipping market. The report presents the results and key factors influencing the balance between the fuel tank volume and the sailing range. The simulated bunker strategies show different possibilities for finding this balance and reducing the operational impact caused by the transition to ammonia.","Green Ammonia; MILP Optimization; Bunker Strategy Optimization; Bunker Port Network; Green Shipping; AIS Data","en","master thesis","","","","","","","","","","","","Marine Technology","",""
"uuid:27ee4f59-1bbc-4274-9912-debb01310d26","http://resolver.tudelft.nl/uuid:27ee4f59-1bbc-4274-9912-debb01310d26","Influence of Business Model Innovation and Competitive Strategies on the Performance of Dutch High-Tech Startups","Sancheti, Avi (TU Delft Technology, Policy and Management)","Khodaei, H. (mentor); Kamp, L.M. (mentor); Scholten, V.E. (graduation committee); Delft University of Technology (degree granting institution)","2024","This master's thesis examines the effects of business model innovation and competitive strategies on the success of high-tech startups in the Netherlands. Understanding how high-tech startups can improve their performance and compete successfully is of utmost relevance given the increasing importance of technology entrepreneurship and the emergence of high-tech startups. High-tech businesses frequently fail within the first 18 months despite their promise; thus, it is necessary to identify techniques that encourage their expansion and success. Considering its significance in Europe and its ability to promote international entrepreneurship, this study concentrates on the Dutch high-tech startup ecosystem. By examining the interaction between business models, competitive strategies, and startup performance, the study seeks to fill a gap in the body of existing literature. The central research question, ""What is the influence of competitive strategies and business model innovation on the performance of high-tech start-ups in the Netherlands?"" serves as the focus of this study.
The study employs a quantitative research approach to gather insights from high-tech businesses established between 2017 and 2020. Data is meticulously collected from high-tech startups in the Netherlands, utilizing a meticulously crafted survey questionnaire. This comprehensive analysis aims to unravel the intricate dynamics between business model innovation and competitive strategies, shedding light on pivotal performance variables such as number of employees and revenue, pivotal indicators of startup growth. Through rigorous statistical analysis performed on a sample of 49 high-tech startups, the study unveils a noteworthy positive correlation between the interaction of business model novelty and cost-leadership strategy with enhanced startup performance, particularly in terms of full-time employees. However, other direct and interactional relationships failed to yield significance concerning the performance variables. Consequently, the study delves into discerning the prevalent business models and preferred competitive strategies within the Dutch high-tech startup ecosystem. Further, despite the significant insights garnered, this research acknowledges certain limitations, including sample size constraints, sampling methodology, and primarily the questions in the survey questionnaire design, which may have influenced the outcomes of the research study.
The results of this study have ramifications for practitioners as well as scholars. By providing insights into the intricate interactions between business models, competitive strategies, and startup performance, it adds to the body of academic literature on strategic management and entrepreneurship. The research also provides important insights from high-tech startups on their decision-making to enhance their performance with developing market trends. The research helps business owners make informed decisions that promote growth, profitability, and market competitiveness by identifying effective combinations of business models and strategies. Delving into these dynamics, this research not only enriches the academic understanding of entrepreneurship but also provides valuable insights with practical implications. Through its rigorous analysis and findings, this thesis aims to equip high-tech startups with the knowledge and strategies needed to succeed in today's dynamic world. In conclusion, this master's thesis provides a thorough examination of the complex linkages between business model innovation, competitive strategies, and the performance outcomes of Dutch high-tech startups.","Business Model Innovation; Competitive Strategy; High-Tech Startups; Firm Performance","en","master thesis","","","","","","","","2024-12-31","","","","Management of Technology (MoT)","",""
"uuid:667642da-a182-4b7c-bc10-864e4fc16674","http://resolver.tudelft.nl/uuid:667642da-a182-4b7c-bc10-864e4fc16674","Integration Technologies for Smart Catheters","Li, J. (TU Delft Electronic Components, Technology and Materials)","Dekker, R. (promotor); French, P.J. (promotor); Delft University of Technology (degree granting institution)","2024","Around 10% of the population will have to go through a catheterization procedure for the treatment of a cardiovascular disease at a certain stage of their lives. During such a procedure, smart catheters will be the ""eyes and ears"" of the surgeons, significantly improving the diagnosis and treatment. However, there have been very limited improvements and innovations in smart catheters over the past decade, as most smart catheters are manufactured with technical point solutions, and therefore cannot sustain themselves with enough production volume for continuous innovation. Consequently, Flexto- Rigid (F2R) was developed as an interconnect platformfor heterogeneous integration of electronic components in submillimeter formfactors. F2R is an open technology platformthat can serve many smart catheter applications from a variety of manufactures. It consists of multiple small and thin silicon islands connected by thin flexible interconnects, which allows devices and components to be mounted with standard assembly techniques or directly fabricated onto the F2R platform. This thesis presents innovations in F2R-based applications, integration, and process optimization for smart catheters. The first part of the thesis is an example of applying F2R for making a miniaturized device, a submillimeter optical data link module (ODLM). With smart catheters migrating from analog to digital instruments, an optical interposer is needed to realize highspeed optical data transmission. The biggest challenge is the form factor of the optical interposer, as it needs to fit into a catheter tip that is inserted inside human veins. This challenge falls exactly in the scope of F2R. The ODLM was fabricated, assembled, and integrated into an ICE catheter demo system. The second part of the thesis presents high-density embedded trench capacitor integration in the F2R platform. Compared to assembling discrete capacitors on F2R, embedded capacitors in the F2R substrate save space in the catheter tip and bring the decoupling capacitors directly underneath the ASICs, resulting in better performance. The work involved the trench capacitor process development, especially the high-aspect ratio (HAR) DRIE trench etching process. More importantly, the trench capacitor process was optimized to be compatible with the standard F2R process. The last part of the thesis presents the work on improving the fabrication process of the F2R platform. The largest bottleneck and most critical step of F2R is the ""buried trench"" process, which creates separated thin silicon islands. The buried trenches consist of thin oxide membranes, that are very sensitive to thin-film stress and other mechanical forces, resulting in reduced production yield. Cavity-BOX SOI eleminates the ""buried trench"" process by introducing a patterned buried oxide layer. The patterned buried oxide mask allows an intact wafer surface during the process until the final DRIE process, which separates the wafer in one go using this oxide mask. The production yield can be significantly improved using the cavity-BOX SOI for the F2R process. A deep brain stimulation (DBS) probe test structure was fabricated with the cavity-BOX SOI based F2R process to demonstrate the technology concept. A method to align the patterns on the wafer to the patterned buried oxide mask was developed.","Cardiovascular diseases; smart catheters; intravascular ultrasound (IVUS) catheter; Flex-to-Rigid (F2R); optical transmitters; optical interconnections; trench capacitors; HAR (High Aspect Ratio) DRIE; SOI substrate; cavity-SOI; cavity-BOX; buried hard-etch mask; miniaturization; deep brain stimulation (DBS); foldable devices; MEMS; Microfabrication; Microassembly","en","doctoral thesis","","978-94-6366-821-7","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:5d837786-9598-460b-b1cb-54dfe7008095","http://resolver.tudelft.nl/uuid:5d837786-9598-460b-b1cb-54dfe7008095","Microstructure development in a case-carburized bearing steel","Abraham Mathews, J. (TU Delft Team Maria Santofimia Navarro)","Sietsma, J. (promotor); Santofimia, Maria Jesus (promotor); Petrov, R.H. (promotor); Delft University of Technology (degree granting institution)","2024","WIND turbines play a crucial role in the global transition towards a sustainable energy future. Maximizing energy production and ensuring a reliable operation is essential to harnessing the full potential of wind energy. Among the critical components, the main shaft bearings have for several years been a focal point due to their significant downtime. In this context, a tribochemical treatment called case-carburization has gained notable attention for enhancing the microstructure of these bearings, to improve their reliability. Case-carburization is a surface treatment technique capable of modifying steel to exhibit a combination of properties such as high fatigue strength, toughness, and wear resistance, that are essential for these bearings as they operate in high-load-bearing environments. In a multi-stage heat treatment process involving case-carburization as the initial stage, the microstructure development at each stage is affected by the final microstructure of the preceding stage. Therefore, a comprehensive understanding of the microstructure at every stage is crucial for assessing its impact on the final microstructure and its properties. This Ph.D. research investigates the microstructure evolution throughout a four-stage heat treatment: carburization, sub-critical isothermal treatment, hardening, and tempering. The second stage is where the sole difference lies with regard to the heat treatment parameters, and is performed along two different routes, also in industrial practise, called the ""bainitic route"" and ""pearlitic route"". One of the primary goals of this research is to understand the microstructure development during the different stages of the two heat treatment routes and to provide an understanding of the microstructural features that can potentially affect the properties/performance of bearings. Additionally, this research also aims to identify the specific stage at which these features form and to provide insight into their formation mechanisms to explore strategies to rectify or mitigate the formation of detrimental features in the microstructure....","","en","doctoral thesis","","978-94-6384-542-7","","","","","","","","","Team Maria Santofimia Navarro","","",""
"uuid:23093bde-4438-46a0-ad48-3b12f7c6ea01","http://resolver.tudelft.nl/uuid:23093bde-4438-46a0-ad48-3b12f7c6ea01","Experimental Study of L-PBF Micro-channel Surface Roughness: An Experimental Study on the Effects of Build Angle on Surface Roughness and Fluid Flow Performance in Laser-Powder Bed Fusion manufactured Micro-channels","Thiam, Arthur (TU Delft Aerospace Engineering)","Cervone, A. (mentor); Gradl, Paul (mentor); Delft University of Technology (degree granting institution)","2024","Progress in Laser powder bed fusion manufacturing has led to greater use of Additive Manufacturing in combustion chambers/nozzles. This allows for the creation of more intricate and efficient solutions, but generates the need for a better understanding of how surface roughness in micro-channels used for engine cooling relates to build angle and performance. The research presented in the framework of this thesis assesses the friction factors and internal surface roughness of 18 additively manufactured channels, through the means of flow testing and microscope inspection. Positive correlations between build angle and friction factors were found, and further investigation revealed relative roughness levels outside the applicability range of Moody charts. Comparison of open and closed contour channels confirmed roughness similarity, providing valuable input for the manufacturing of witness channels in cost/time sensitive applications. Finally, the relation between surface roughness parameters and sand-grain roughness were investigated, revealing their dependency on flow properties.","LPBF; Laser Powder Bed Fusion; Additive Manufacturing; Channel flow; surface roughness; Liquid rocket engine; surface texture; build angle; Cooling channels","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:8100ecad-ef5f-4e62-ab4d-73cef93b7826","http://resolver.tudelft.nl/uuid:8100ecad-ef5f-4e62-ab4d-73cef93b7826","The Effect of ECM Stiffness on Tip/Stalk Cell Patterning during Early Sprouting Angiogenesis: A computational approach","Waasdorp, Britt (TU Delft Electrical Engineering, Mathematics and Computer Science)","Dubbeldam, J.L.A. (mentor); Rens, E.G. (graduation committee); van Gijzen, M.B. (graduation committee); Checa, Sara (graduation committee); Delft University of Technology (degree granting institution)","2024","Angiogenesis, i.e. the formation of blood vessels from existing ones, plays a vital role in bone or wound healing. The expansion of vascularization facilitates the healing process through the delivery of oxygen and nutrients to the injured site and through the removal of waste products. Clinical observations indicate that impaired angiogenesis can impede the healing process, or can result in non-healing outcomes.
The computational model developed in this thesis predicts tip/stalk cell patterning, marking the initial phase of sprouting angiogenesis. Growth factors signal endothelial cells to differentiate into tip and stalk cells. Tip cells branch from the existing vessel, leading the sprout, while stalk cells proliferate and follow behind, forming the newly emerged blood vessel. Understanding tip/stalk cell patterning is vital to ensure successful angiogenesis, as an excess or deficiency in tip cells leads to improper healing.
Despite several experimental studies and mathematical models exploring the signaling pathways behind tip cell selection, there is a noticeable gap regarding the effect of extracellular matrix (ECM) stiffness on this process. Given that alterations in stiffness occur in various physiological and pathological processes, comprehension of this effect is clinically relevant. This thesis aims to address the existing gap by investigating the specific influence of ECM stiffness on tip/stalk cell patterning.
A computational model is created that simulates a vessel sprout under stimulation of growth factors. This model is able to predict the cell patterning over various ECM stiffness levels, and highlights the relevance of incorporating ECM stiffness in the investigation of angiogenic treatments.
Enhancing the models’ accuracy and validating the ECM stiffness-dependent model predictions requires additional experimental data. However, further development of the model has great potential for deepening our understanding of angiogenesis dynamics and for facilitating the investigation of treatment strategies.","Angiogenesis; Cell Patterning; Mathematical Modelling; Computational Modelling; ECM Stiffness; Tip Cell Selection; Notch Signalling","en","master thesis","","","","","","","","","","","","Applied Mathematics","",""
"uuid:17530d48-4c76-4972-ab62-087d2abc66bf","http://resolver.tudelft.nl/uuid:17530d48-4c76-4972-ab62-087d2abc66bf","The effects of passing seagoing vessels on the inland ships in the outer harbour and locks of Hansweert","Heijboer, Dick (TU Delft Civil Engineering & Geosciences)","de Boom, L. (mentor); van Koningsveld, M. (mentor); van der Hout, A.J. (mentor); Tissier, M.F.S. (mentor); Delft University of Technology (degree granting institution)","2024","The lock of Hansweert, located in the province of Zeeland in the Netherlands, serves as a crucial inland shipping node between the Western Scheldt estuary and the Rhine Delta. The outer harbour of the lock complex provides the connection to the Western Scheldt and accommodates waiting facilities for inland ships. The Western Scheldt is a vital gateway for maritime traffic, linking the Port of Antwerp to the North Sea. As the navigation channel of the Western Scheldt is located close to the outer harbour of Hansweert, multiple ship incidents at this location are attributed to the water motions generated by passing seagoing vessels on the Western Scheldt. This research investigates how the water motions induced by passing vessels in the Western Scheldt contribute to unsafe situations in the outer harbour and locks of Hansweert, and what preventative measures can be identified to effectively minimize incidents and mitigate risks.
Investigating the incident records reveals that the key contributors are the primary water motions generated by the passing vessels in the Western Scheldt. The phenomenon, experienced as a sudden lowering of the water level and suction forces, can lead to the breakage of mooring lines and uncontrolled movements of inland ships, resulting in a range of safety hazards and operational disruptions. Several documented incidents, field studies and interviews highlight the urgency for effective measures to mitigate the potentially harmful effects of passing vessels on the ships in the Hansweert outer harbour and locks.
A seven-week measurement campaign, involving 1281 passages of so-called oversized vessels, reveals distinct patterns of water level fluctuations during a vessel’s passage. A vessel is considered oversized if its length exceeds 210 metres or if its draught is larger than 10 metres. These patterns are described as a translatory drawdown wave travelling into the harbour, reflecting against the lock complex and oscillating back and forth in the outer harbour until dampened. The key parameter characterizing this wave is the lowering of the water level, referred to as the drawdown height. The average measured drawdown height approximates 6 centimetres, with maximum observations up to 40 centimetres. The main factors influencing the drawdown height are the vessel’s passing distance to the outer harbour, its speed relative to the currents and its dimensions, shown by a correlation analysis between the parameters describing the passing vessel and the generated drawdown height. Extreme drawdown events were exclusively observed during a combination of a relatively high speed through the water of the seagoing vessel and small passing distances relative to the harbour’s entrance.
The impact of the drawdown effects on the inland ships is determined by the forces generated by the pressure difference along the ships, caused by the inclination of the water level. A critical drawdown height of 12 centimetres is set, based on existing force criteria and the linear relation between the drawdown height and water level slope. To improve on the existing drawdown height prediction methods, a site-specific drawdown height prediction equation has been derived. Validation of this equation using the observations made during the measurement campaign yields a Pearson correlation coefficient of 0.81 and an Mean Absolute Error score of 2.2 centimetres.
Preventative measures are identified, aiming to minimize incidents and mitigate the risks related to the water motions induced by passing vessels. The predicted drawdown, generated by the passing vessel, is kept below the critical level by recommending a maximum speed related to the passing distance and dimensions of the vessel. Practically, this measure could be applied as a calculation tool or as an overlay on the pilot’s electronic sea chart. Coupling this information with awareness campaigns for pilots will contribute to minimizing the adverse effects on the ships in the outer harbour. The resilience against drawdown-induced risks could be strengthened by restricting the maximum combined width of ships moored alongside. Furthermore, by limiting the excessive slack in the lines of the moored ships, through signage and floating bollards, the movements of the ships will be restricted, reducing the risk of line breakage. Notifications of anticipated critical drawdowns would allow traffic controllers or lock operators to caution the inland ships and delay the lock chamber door openings, whilst alerting the passing vessel. Incorporating the mitigation measures recommended in this research could positively impact the safety of navigation in the Hansweert outer harbour and locks.","ship waves; Ship response; Western Scheldt; Inland shipping; primairy water motion; drawdown","en","master thesis","","","","","","","","","","","","Civil Engineering | Hydraulic Engineering","","51.4396, 4.01111"
"uuid:0d57b4ce-42c2-423e-a4e0-b62b6a842a54","http://resolver.tudelft.nl/uuid:0d57b4ce-42c2-423e-a4e0-b62b6a842a54","Revitalizing CMUTs","Kawasaki, S. (TU Delft Electronic Components, Technology and Materials)","Dekker, R. (promotor); Giagka, Vasiliki (copromotor); Delft University of Technology (degree granting institution)","2024","CMUTs (Capacitive Micromachined Ultrasonic Transducers) are causing a technological revolution. Research over the last decade showed that CMUTs can sufficiently replace traditional ultrasound technology based on the bulk PZT, along with other benefits such as lower assembly cost, broader bandwidth and monolithic integration capability with ASICs. Furthermore, devices can be fabricated from with non-toxic materials and eliminate the environmental impact that is associated to PZT. As a result, in recent years we are seeing low-cost consumer level ultrasound imaging technology becoming available for point of care diagnostics devices from startup companies. However, surprisingly, CMUT technology adoption is still lagging behind what we would expect. Thus, in this thesis three novel CMUT applications are investigated to show-case the untapped potentials of CMUTs which should lead to further traction for the CMUT field. By reading this work it is my wish that the reader could understand the hugely prosperous future of CMUTs.","Ultrasound; MEMS; CMUT; ultrasound power transfer; pre-charged CMUTs; microfluidic particle separation; ultrasound neurostimulation","en","doctoral thesis","","978-94-6473-390-7","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:340d4e2f-f82e-4e7a-b095-abf5404e7a8b","http://resolver.tudelft.nl/uuid:340d4e2f-f82e-4e7a-b095-abf5404e7a8b","Design Study on the Feasibility of a Self-closing Flood Barrier: A Case Study of the City of Arcen, Limburg","Jhinkoe-Rai, Suryand (TU Delft Civil Engineering & Geosciences)","Kok, M. (mentor); Voorendt, M.Z. (mentor); van Nederveen, G.A. (mentor); Nooij, Ruud (mentor); Delft University of Technology (degree granting institution)","2024","Flood risks and its consequences become more and more challenging and are demanding for the currently present dike systems and hydraulic structures in the Netherlands. This automatically raises the question for the possibility of adjustable temporary deployable flood defences that work autonomously. Nowadays it is more likely that a standard earthen dike will not be possible everywhere, due to site-specific characteristics such as available space or protected townscape. At these specific locations, a self-closing flood barrier can offer a solution, in view of minimally affecting the spatial quality with a reliable solution. The goal of this design study is to gain insight in the feasibility of applying a self-closing flood barrier in areas where spatial quality plays an important role and where the hydraulic boundary conditions demand for heavier structures. With the increase of densely built areas nowadays, the concept of an autonomously closing barrier is promising and an interesting alternative to consider.
In this thesis the objective is to develop a customised design of an adaptive self-closing flood barrier in the upper river region of the Netherlands. The city of Arcen in this case study is characterised by its cultural-historical values and its strong connection to the Meuse. This makes it difficult to construct conventional earthen dikes.
For the design purpose software with statistical data such as Hydra-NL is used to provide site characteristics, hydraulic and geotechnical boundary conditions and literature for information on currently applied barrier types and drive mechanisms. Furthermore, the design process has been completed with the help of the Design Guide Hydraulic Structures of Rijkswaterstaat and the Eurocode, from which a design originated in which stability and strength requirements have been met. The design resulted in a floating flat barrier of steel, which does not involve a complex design and is in line with integrating the structure in the area with minimal hindrance. In the design the focus lies on the functionality and the structural integrity with an in-depth look at adaptability and integrability.
The result shows that the design of a floating flat barrier is feasible as a self-closing structure in the city of Arcen. However, because of the location of the structure with the requirement of no townscape obstructing elements, a heavy support structure is needed for a design water level of 2.5 m above the ground surface. Furthermore, the applied boundary conditions leads to a large floater, even though the structure is slender. In order to develop a complete design, it is recommended to make a detailed design on the concrete foundation, to do a cost analysis on the construction and materials and investigate how a certain structure is received by the residents of Arcen. This will gain insight in areas to optimise the design furthermore.
This study focused on enhancing our understanding of the interaction between smart building technology and users. A specific focus is placed on climate control technology within the broader landscape of smart building systems. By employing an exploratory approach, in which a combination of qualitative and quantitative methods was utilized, smart building users’ preferences and behavioral mechanisms were explored. Through semi-structured interviews with smart building occupants, the study delved deeper into understanding the motivations, barriers, and other aspects of occupant behavior and interactions with smart building technology. Additionally, insights from interviews with industry experts provided valuable perspectives on which key factors contribute to the increased adoption of smart building technology. These qualitative findings were complemented by quantitative data collected through an online survey (n=92), which allowed trends and preferences to be identified from a larger group of smart building occupants.
The study showed that the successful implementation of smart building technology goes beyond mere technological details. It provided empirical insights into the preferences and behavioral mechanisms of smart building occupants, filling a gap in the existing literature. By exploring these aspects, the research deepened our understanding of user interactions within smart buildings. Consequently, it advocates for a user-centered approach to smart building initiatives, emphasizing the importance of understanding human preferences and incorporating user feedback to effectively adapt technology to their specific needs and routines. However, the study revealed a diverse range of user preferences and motivations regarding interaction with smart building technology, including preferences regarding control levels, system feedback, transparency, flexibility, and interface design. This diversity highlighted the absence of a one-size-fits-all approach to implementing smart building technology. Consequently, specific practical recommendations were developed to guide stakeholders in smart building initiatives, emphasizing a more user-centered implementation that ensures adaptability to the unique needs and preferences of building users.
results of the simulations are extracted and post-processed into margins of safety (MoS) using the direct results or (semi-)analytical equations for each individual component. In total five failure modes are assessed, which are Von Mises stress, displacement of engine, crippling, panel buckling and column buckling. The most critical MoS and the relation to the parameters is used in combination with an adaptive damping parameter to optimize each individual part. This design methodology is tested using the Flying-V, which is a novel aircraft configuration in the shape of a V, as a reference aircraft. Therefore, first the requirements, critical loadcases, loads and initial design have been developed based on regulations and previous research regarding the Flying-V and have been used as input for the CAD model and simulations. The design methodology has proven not be perfect as regions with stress concentration cause the minimum MoS to be below zero for all iterations and could not be solved within the time frame of this research. However, the design methodology has proven to be significantly faster compared to a design of experiments used in previous research. Overall it should be noted that there are still many other limitations regarding this method. These limitations are related to the limited amount of failure modes used and the fact that it still requires some kind of Design of Experiment, which is time consuming. The final mass of an optimized engine mounting structure is estimated to be approximately 40% higher than the design methodology used in previous research, which is due to the higher amount of details in the design as well as the significant higher estimated mass for the engine. This means that the current estimated mass for the full engine mounting structure including landing gear and engine is approximately 22150 kg compared to the estimated 17360 kg before.
Furthermore, an assessment of the influence of the developed design on the crashworthiness of the Flying-V has been done. This assessment focuses on one of the four main criteria regarding occupant protection, namely the guarantee of acceptable acceleration and loads sustained by the occupants. This is done by connecting the engine mounting structure to the developed wing-fuselage structure of the Flying-V with a tie connection. In order to compare different cases a new variable has been created, which is based on empirical equations developed by the U.S. Air Force. In addition, a new method based on moments of inertia has been developed to take the rest of the aircraft into account without increasing the size and thus computational effort of the simulation. To validate this method, the wing-fuselage structure has first been extended to fit the structure and results are compared to previous research. This has shown large, unexpected, differences which could not be explained even with thorough investigation. Applying the inertia method to the extended fuselage has shown small but explainable and expected differences, validating that the method has no unforeseen effects on further results. Simulations using this inertia method and the wing-fuselage with full engine mounting structure shows an improved performance in crashworthiness as the engine mount also absorbs some of the energy. Similar simulation without engine shows an even more improved performance, meaning that engine separation is of interest for the Flying-V. Initial further-reaching investigation into engine separation, using a point-mass model, shows that engine separation might be possible without impacting the Flying-V for crashes without any initial yaw, pitch or roll angle.","Engine pylon structure; Unconventional aircraft; Crashworthiness; Design methodology","en","master thesis","","","","","","","","","","","","Aerospace Engineering","Flying-V",""
"uuid:f84137ec-4851-4bf0-8e20-49e480e72eaf","http://resolver.tudelft.nl/uuid:f84137ec-4851-4bf0-8e20-49e480e72eaf","Technical errors in a novel mixed reality navigation system for orthopedic implant surgery","van Bakel, Roan (TU Delft Mechanical, Maritime and Materials Engineering)","Weinans, Harrie (mentor); van der Wal, Bart C.H. (graduation committee); Nguyen, Chien (graduation committee); Delft University of Technology (degree granting institution)","2024","Introduction
An innovative, patient-specific, hip implant was developed for canine patients suffering from developmental hip dysplasia. In a first cohort study, the post-operative positions of the implants deviated with an average of 5 mm when compared to the pre-operatively planned positions. A novel augmented reality (AR) based intra-operative navigation method (Holoma) was proposed to decrease implant positioning errors to a maximum of 3 mm. Holoma provides ArUco marker-based, mixed reality surgical navigation on the Hololens 2. The goal of this study was to quantify the error associated with each technical component in Holoma, to determine its navigational accuracies.
Methods
Holoma’s technical errors were quantified in a laboratory setting within a surgical operation room. The accuracy of ArUco marker localization and the amount of jittering (falsely detected marker movement) were tested by performing stationary and dynamic experiments. The precision of three image-to-patient registration methods (marker pose, point-to-point, point cloud) was determined by calculating the euclidean distance between multiple registration attempts. Lastly, implant navigation accuracy was quantified by positioning an implant on a precisely predetermined position and recording Holoma’s navigation instructions.
Results
Holoma’s ArUco marker localization accuracy had a median error of -0.97 mm (min; max: -2.04; -0.27) with a marker-to-camera distance of 60 cm, and median jittering was 0.65 mm (min; max: 0; 2.07). Median image-to-patient registration precision was 2.20 mm (min; max: 0.39; 6.00), 3.52 mm (0.21; 6.92), and 3.79 mm (0.55; 8.83), for marker pose, point-to-point, and point cloud registration, respectively. Lastly, implant navigation instructions showed median errors of 2 mm (min; max: 0; 7), 3 mm (0; 7), and 4 mm (0; 9) after marker pose, point-to-point, and point cloud registration, respectively.
Discussion and conclusion
The experiments suggest an accumulation of technical errors in Holoma’s navigation application. The accuracy and precision of the navigation software were determined to be inadequate to decrease patient specific hip implant placement errors, at the time of investigating. Future improvements within Holoma will determine its feasibility for accurate implant navigation. Other navigation techniques should be considered in the search for optimal implant positioning guidance.
Purpose: The construction industry is responsible for great amounts of resource consumption, waste generation and both carbon and greenhouse gas emissions in the European Union. The currently still predominant linear mindset of take-make-consume-dispose must shift to reduce the industry’s environmental impact and enable the transition towards a circular construction industry. Circular material hubs facilitate more circularity by collecting, processing, and redistributing secondary building components to make them available for another life cycle. In literature, little can be found about the system circular material hubs are embedded in and their connection to architects. This study investigates the system of circular material hubs in the Netherlands, its challenges, opportunities, and potential future developments in the transition towards a circular construction industry. A special focus is placed on the role of architects within this system, as a circular construction industry also needs designers to include secondary building components in designs. The Netherlands is one of the top nations in the reuse of secondary raw materials and therefore provides as an exemplary setting for this exploratory research.
Methodology: An exploratory, qualitative research approach was chosen. Fourteen semi-structured interviews were conducted with representatives from circular material hubs, architects, as well as experts in the fields of circular economy, circular construction industry and construction logistics. Practitioner interviews aimed at identifying practices performed within the system of circular material hubs, and detecting challenges, opportunities and potential future developments as perceived by practitioners in the field. Expert interviews were conducted to validate the information gathered through literature review and practitioner interviews.
Findings: The research found four practice bundles which are important for the system of circular material hubs. These practice bundles are acquisition practice, processing practices, sales practices, and material harvesting practices. Within these practice bundles, different practices and performances of these practices were identified. The practices influence each other. Which building components are acquired influences which processing practices need to be performed. The type of building component also influences the sales practice as different building components target different groups of clients and are sold through different communication channels. It is also crucial whether the building components are sold offline or online. The online marketplace of Insert was found to be particularly helpful, as it is specifically designed for the construction industry and used by circular material hubs as well as architects. This shows the influence of the choice of communication channel on a circular design practice and scouting practices. By providing as much information as possible about the secondary building component at hand, circular material hubs also facilitate a circular design practice. Additionally, challenges, opportunities, and potential future developments of the system of circular material hubs were identified. Challenges the system faces are related to uncertainty and irregular assortment, guidelines, costs, and the provision of guarantees, while opportunities are governmental decisions, the provision of information and the use of shared online marketplaces. Missing collaborations are both a challenge and an opportunity. Future developments are primarily related to changes in the provision of secondary building components.
Research limitations: The limitations of this study are that social practice theory was not applied to the entire research as it is not suitable for the assessment of challenges, opportunities, and potential future developments. A greater variety of circular material hubs, not in number but in their field of activity, could present a different view on the system. Semi-structured interviews also always have certain limitations. Identifying the practices while they are being performed could also have led to more in-depth results.
Originality/value: By providing a comprehensive view on the system of circular material hubs in the Netherlands, this research helps to understand the dynamics within the system and allows the identification of potential interventions based on the practices that constitute the system.","circular construction industry; circular material hubs; material scouting; social practices; circular design","en","master thesis","","","","","","","","","","","","Metropolitan Analysis, Design and Engineering (MADE)","",""
"uuid:6dad7119-1455-4bd0-9439-ce5ba0962857","http://resolver.tudelft.nl/uuid:6dad7119-1455-4bd0-9439-ce5ba0962857","Water City Vienna - Transitioning Towards Climate Resiliency","Morscher, Leon (TU Delft Architecture and the Built Environment)","Hausleitner, B. (graduation committee); Furlan, C. (mentor); Delft University of Technology (degree granting institution)","2024","This thesis project explores the imperative of strenghening Vienna's climate resilience through mitigating weather extremes and fostering knowledge of them by reimagining its current water and ecosystem dynamics. The central focus is on integrating a blue-green infrastructure into the urban environment and a just distribution of their services, thereby establishing a balanced coexistence with the ecosystem.
The objectives encompass mitigating pressing urban challenges such as the urban heat island effect and biodiversity loss, while fostering awareness of the symbiotic relationship between a healthy ecosystem and human well-being. These efforts are pivotal in the city's journey toward climate resilience and adapting to dynamic climate conditions.
The broader aspiration is to illuminate a path towards socially and environmentally sustainable urban transformations.","Climate resilience; Green-blue infrastructure; Environmental Justice; Landscape Urbanism; Vienna; Urban Ecology; Socio-Ecological System; Research by design","en","master thesis","","","","","","","Campus only","","","","","Architecture, Urbanism and Building Sciences | Urbanism","Master thesis project","48.2082, 16.3719"
"uuid:ae0b272f-455d-468a-8965-fc263e14a3dc","http://resolver.tudelft.nl/uuid:ae0b272f-455d-468a-8965-fc263e14a3dc","Pallas: Novel Sound Classification at the Edge","Groenenboom, Max (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Networked Systems)","Zuniga, Marco (mentor); Liang, K. (graduation committee); Delft University of Technology (degree granting institution)","2024","Sound pollution is becoming an increasingly pressing issue in today’s world. To effectively address it, it must be measured. To this end, Serval was developed, an edge-ai powered sound recognition solution. Its lack of accuracy, however, makes it difficult to deploy. This thesis examines the potential for improving this solution while staying within its technical limitations in order to raise the accuracy to satisfactory levels. Multiple aspects of Serval were evaluated and compared to the current stateof-the-art: its data augmentation, the embedding it uses, and the hardware it runs on. Alternatives for each of these components were evaluated and each aspect was optimized.
The results show that after these improvements, the single-label F1-score increased from 0.60 to 0.76, and the single- and multi-label combined F1-score increased from 0.64 to 0.67. Finally, power consumption has been reduced by 14%, partially thanks to the usage of specialized hardware. One issue that has yet to be adequately addressed is the size of the dataset. By increasing the number of samples, the accuracy could be further improved.","Audio classification; Machine listening; Data augmentation; Noise pollution; Environmental sound classification","en","master thesis","","","","","","","","","","","","Electrical Engineering | Embedded Systems","",""
"uuid:71e250d5-28ab-49b2-ba54-1b3f79906561","http://resolver.tudelft.nl/uuid:71e250d5-28ab-49b2-ba54-1b3f79906561","Topology and variable optimization of a planar quasi-zero stiffness mechanism for motion isolation during the installation of wind turbine blades","de Groot, Patrick (TU Delft Mechanical, Maritime and Materials Engineering)","Aragon, A.M. (mentor); Holtzer, B. (mentor); Wellens, P.R. (graduation committee); Radaelli, G. (graduation committee); Koppen, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","Current service and installation activities for offshore wind turbines are carried out by jack-up vessels, which eliminate wave disturbances to a large extent. The use of these vessels imposes several disadvantages, including high operational costs and the limitation of operating in restricted water depths. An alternative is a crane mounted on a floating vessel (monohull), which is quicker in operation and multi-deployable. With these vessels, however, a motion compensator is needed to eliminate most of the hydrodynamic disturbances. The purpose of this graduation assignment is to develop a concept design for a passive motion compensator (PMC) to isolate the vessel motion from the payload.
This goal is achieved by the implementation of a multi-objective optimization algorithm based on genetic programming (GP) that constructs a two-dimensional PMC based on the principle of quasi-zero stiffness. The GP employs a set of genetic operators to explore the design space in terms of topology and design variables, which effectively mimics Darwin’s Theory of Evolution. The better a mechanism performs, the higher the fitness, and thus the higher the chance this design appear in future generations.
Each design is a composition of cylinders and nodes that are assembled into a mechanism. During the fitness evaluation, all mechanisms are examined by a nonlinear finite element method to extract the force-displacement relations. The arc-length control method is used due to the large displacements and rotations of the members in the mechanism, whereby both the nodal displacement vector and external load vector are varied to follow an equilibrium path in an incremental-iterative way. To provide sufficient support to the payload, the mechanism is prestressed, which is applied by using the arc-length procedure as well.
Static and dynamic results show that the GP is suitable for constructing a high-level planar QZS mechanism for the intended application in various sea states. From multiple runs, it can be concluded that the optimizer generally produces designs with the same topology. Dynamic analyses in the time domain show that motions are effectively mitigated in the horizontal and vertical directions for the chosen designs. In addition, analysis in the frequency domain shows that the mechanisms effectively attenuate motions in the frequencies of interest.
Leveraging co-creation sessions and interviews with employees of TD, the study shows that the internal team’s focus is seen as the main barrier to multidisciplinary collaboration within TD. This focus stems from team-specific targets, that discourage collaborative efforts between teams and cause each team to prioritise their own proposition to clients. As a result, clients are unaware of other services offered by TD and employees under-utilise the expertise of their colleagues. This internal team focus comes from TD’s existing organisational structure. Therefore, a new organisational structure is proposed as the final solution for TD. The proposed organisational structure introduces dynamic, project-based teams that replace traditional, static teams, facilitating fluid cross-domain collaboration and enabling a more agile response to client needs. The expected positive impact of the final design for clients is a broader service offering and improved client satisfaction, and enhanced learning and innovation for employees of TD.
The report concludes with recommendations for the adoption of the new structure and recommendations for future work. The first aim to mitigate the reorganisation’s potential challenges, like coordination & communication and a loss of team identity and include involving employees for successful implementation. The latter suggested areas for further research, including broadening the focus group, incorporating diverse research methodologies and conducting follow-up studies to assess the impact of the changes implemented.
The findings provide valuable insights into employees’ perception of the current situation, the barriers to collaboration and the desire for engaging employees in decision making. To align with employee demands and enhance multidisciplinary collaboration, TD is recommended to transition towards the proposed organisational structure that facilitates dynamic project team configurations.","co-creation; organisational structure; synergy; collaboration; creative agency","en","master thesis","","","","","","","","","","","","Strategic Product Design","",""
"uuid:654f32ea-d3df-4804-8d67-eb2dd89d20e5","http://resolver.tudelft.nl/uuid:654f32ea-d3df-4804-8d67-eb2dd89d20e5","Securing Power Side Channels by Design","Aljuffri, A.A.M. (TU Delft Computer Engineering)","Hamdioui, S. (promotor); Taouil, M. (copromotor); Delft University of Technology (degree granting institution)","2024","The security of electronic devices holds the greatest importance in the modern digital era, with one of the emerging challenges being the widespread occurrence of hardware attacks. The aforementioned attacks present a substantial risk to hardware devices, and it is of utmost importance to comprehend the potential detrimental effects they may cause. Side-channel attacks are a class of hardware attacks that exploit information unintentionally leaked by a device during its operation. These leaks manifest in various forms, including power consumption, time variations, and thermal dissipation. The fundamental danger posed by side-channel attacks is their ability to infer sensitive information from these unintended emissions. To address the heightened risks associated with side-channel attacks, this thesis focuses on three main research topics.","Side Channel Analysis; Power Attacks; Countermeasures; Leakage Assessment Framework","en","doctoral thesis","","978-94-6384-544-1","","","","","","","","","Computer Engineering","","",""
"uuid:764408e4-72c1-4cf9-8bff-1ce20b8944b2","http://resolver.tudelft.nl/uuid:764408e4-72c1-4cf9-8bff-1ce20b8944b2","Interactive Intelligence: Multimodal AI for Real-Time Interaction Loop towards Attentive E-Reading","Lee, Y. (TU Delft Web Information Systems)","Specht, M.M. (promotor); Migut, M.A. (copromotor); Delft University of Technology (degree granting institution)","2024","E-learning has shifted the traditional learning paradigms in higher education, offering more flexible, ubiquitous, and personalized learning experiences. The previous years COVID-19 pandemic required a re-calibration of education to accommodate virtual learning environments from the traditional classroom-based education. Widespread learning platforms and digital devices have accelerated the adoption of e-learning , and now, it plays a central role in formal and informal education.","Machine learning; Deep learning; Computer vision; Multimodal reasoning; Learning Analytics; Human Attention; E-reading; Real-time feedback loop; Human-Robot Interaction (HRI); Human-Computer Interaction (HCI)","en","doctoral thesis","","978-94-6366-824-8","","","","","","","","","Web Information Systems","","",""
"uuid:9ab2b4ba-8f91-4891-8190-4a96f77c471e","http://resolver.tudelft.nl/uuid:9ab2b4ba-8f91-4891-8190-4a96f77c471e","Adaptive Visual Servoing Control for Quadrotors: A Bio-inspired Strategy Using Active Vision","Hazelaar, Sander (TU Delft Aerospace Engineering)","de Croon, G.C.H.E. (mentor); Yedutenko, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","New insights into the landing behavior of bumblebees show an adaptive strategy where the optical flow expansion of the landing target is step-wise regulated. In this article, the potential benefits of this approach are studied by replicating the landing experiment with a quadrotor. To this end, an open-loop switching method is developed, enabling fast steps in divergence. An adaptive control law is used to deal with non-linear system dynamics, where the control gain is scheduled based on the control effectiveness of the actuator inputs during the steps. It is demonstrated that the quadrotor can reliably land on the target from varying initial positions, and the switching strategy shows a slight reduction in landing time compared to a constant divergence strategy with the same average divergence over distance. This strategy also reduces the maximum velocity during the landing.","Visual Servoing; Autonomous Landing; Quadrotor Control; Non-linear systems; Computer Vision","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:5cdae823-66c5-40e2-b624-29da6a3d8456","http://resolver.tudelft.nl/uuid:5cdae823-66c5-40e2-b624-29da6a3d8456","Automated Carnegie Staging of the Human Embryo in 3D Ultrasound using Deep Learning","Niemantsverdriet, Ruben (TU Delft Mechanical, Maritime and Materials Engineering)","Vos, F.M. (mentor); Bastiaansen, Wietske (mentor); Klein, Stefan (mentor); Rousian, Melek (mentor); Delft University of Technology (degree granting institution)","2024","The periconceptional period, encompassing the embryonic phase, is a critical window where a majority of reproductive failures, pregnancy complications, and adverse pregnancy outcomes arise. The Carnegie staging system comprises 23 stages which are based on embryonic morphological development. This allows for the assessment of normal and abnormal embryonic development during this critical period. In-utero Carnegie staging using three-dimensional (3D) ultrasound scans visualized with virtual reality offers valuable insights but is currently a time-consuming manual process. To address this, we propose a deep learning approach for Carnegie staging in 3D ultrasound scans.
We used a dataset comprising 1413 3D ultrasound scans from the Rotterdam Periconceptional Cohort, annotated with Carnegie stages spanning from stages 13 to 23, including fetal subjects. Various training strategies were explored. We compared a metric regression approach, which considers the ordered nature of the Carnegie stages by treating the Carnegie stages as a continuous variable, with a multi-class classification approach, treating stages as independent categories. Additionally, we evaluated the influence of using a loss function accommodating the categorical nature of the Carnegie stages in the metric regression approach and examined the impact of incorporating embryonic size in the model input. Ultimately, a regression approach using the Mean Squared Error (MSE) loss function emerged as the optimal choice.
This model achieved a classification accuracy of 0.59 and a Root Mean Squared Error (RMSE) of 0.62 on the test set. This performance is comparable to an intermediate human rater, which achieved an accuracy of 0.63 and a RMSE of 0.65. Our findings represent a significant step towards the development of an automated Carnegie staging method, offering the potential for a more comprehensive evaluation of the critical embryonic phase in the clinic.","Machine Learning; Deep Learning; embryonic development; 3D Ultrasound","en","master thesis","","","","","","","","","","","","Biomedical Engineering | Medical Physics","",""
"uuid:e9e845e4-fd01-4a9c-8d44-a4e3d7dfe2bf","http://resolver.tudelft.nl/uuid:e9e845e4-fd01-4a9c-8d44-a4e3d7dfe2bf","Investigating the Risk of Galveston's Proposed Floating Sector Gates Failing Under Reverse Loading Conditions","Metselaar, Meno (TU Delft Civil Engineering & Geosciences)","Jonkman, Sebastiaan N. (mentor); Labeur, R.J. (mentor); Schoemaker, M.A. (mentor); Mooyaart, L.F. (mentor); Delft University of Technology (degree granting institution)","2024","br","Galveston Bay; Floating sector gates; Storm surge barrier; Reverse loading; Reverse head; Wave loading; Delft 3D flexible mesh; Hurricane; Storm surge; Risk; Probabilistic; Exceedance probability","en","master thesis","","","","","","","","2025-02-21","","","","Civil Engineering","","29.350629489725065, -94.7675911959141"
"uuid:9a295d44-1e95-4911-a4a2-4a96c498fe79","http://resolver.tudelft.nl/uuid:9a295d44-1e95-4911-a4a2-4a96c498fe79","Design of an inherently fully dynamically balanced aerial manipulator with omnidirectional workspace","Bom, Alexander (TU Delft Mechanical, Maritime and Materials Engineering)","van der Wijk, V. (mentor); Hamaza, S. (mentor); Herder, J.L. (graduation committee); Goosen, J.F.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","Drones are increasingly used nowadays, primarily for visual inspection tasks facilitated by onboard cameras. The field of aerial manipulation tries to expand the capabilities of drones by attaching a manipulator, enabling physical interaction. Unfortunately, the usability of aerial manipulators is hindered by disturbances resulting from the movements of the manipulator. These disturbances, including reaction forces and a shifting centre of mass, not only affect manipulation accuracy but also pose safety risks by potentially destabilizing the drone. In this thesis, a design is presented that addresses this challenge by leveraging the theory of dynamic balance.
A new design approach of making a manipulator fly, instead of the common approach of mounting a manipulator arm to a drone was used. This new approach avoids interference with the drone's components, allowing to focus on the design of the manipulator arm. Furthermore, it made it possible to create a manipulator which can manipulate above, to the side and underneath itself. This makes the presented manipulator arm more versatile than common aerial manipulators whose workspace is mostly located only above or below the drone. The kinematics, workspace and balance conditions of the manipulator arm are presented. Furthermore, the design's workspace is optimised while the mass of the manipulator is minimized in a bilevel optimisation. Finally, the design is validated both by simulation and measurements performed with the built prototype.
The design presented is the first inherently fully dynamically balanced manipulator with omnidirectional workspace which can be used for aerial manipulation.
Initially, we build upon an existing framework for quadruped jumps, where we refine the trajectory optimization (TO) algorithm and introduce a new Variable Impedance Control (VIC). The VIC is specifically developed to facilitate softer landings. This improved system was then utilized to generate a comprehensive synthetic dataset, including 11,000 samples that cover a diverse range of jumping scenarios. This dataset served as the foundation for training a neural network. The primary objective of the network is to emulate the performance of the model-based approach. Structurally, the network is designed to process the robot's current state as input and generate the corresponding control actions for its 12 motors as output.
The most significant achievement of this research is the neural network's ability to closely replicate the outcomes of the model-based solution. Notably, it ensures more compliant behavior and lower stress on the motors during the landing phase than an MPC. The neural network demonstrates a 97.4% success rate. This high level of performance underscores its potential for on-the-fly application in robotic systems. The effectiveness of our method is further validated through a series of simulations and practical tests conducted on a Go1 quadruped robot.","Behavior Cloning; Robotics; Variable Impedance Control; Soft Landing; Quadruped; Jumping","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:3a82e7c5-b7d4-435c-ab48-4949846a2ef8","http://resolver.tudelft.nl/uuid:3a82e7c5-b7d4-435c-ab48-4949846a2ef8","A Systemic Approach to implement Education for Sustainable Development in Applied Sciences: A Case-study of the TU Delft Applied Sciences Faculty","Wijnia, Puck (TU Delft Technology, Policy and Management)","Gammon, A.R. (mentor); Kamp, L.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis delves into the pivotal role of engineering education in equipping students to tackle the challenges posed by climate change. Despite widespread efforts in higher education institutions, particularly in engineering, to incorporate education for sustainable development (ESD), effectiveness often falls short, leading to a regression to previous norms. Moreover, there is a dearth of literature on the implementation of ESD in applied sciences (AS) institutions, compounding the issue. This study focuses on the AS Faculty at TU Delft, which, despite ambitious climate goals, has a low percentage of courses addressing sustainability. The emphasis is on a systemic approach to ESD implementation, with the aim of providing recommendations for the educational portfolio of the Climate Action Plan of the AS Faculty of TU Delft.
The study begins with an extensive literature review on ESD implementation and systemic change within higher (engineering) education institutions (HE(E)Is). Findings elucidate specific strategies, barriers, drivers, and uncertainty factors, emphasizing the significance of context and culture. Two case studies on universities of applied sciences, NHL Stenden and Van Hall Larenstein, are conducted to contextualize theoretical insights within the AS Faculty at TU Delft. These case studies provide real-life examples of systemic ESD implementation, highlighting associated challenges and successes.
Subsequently, the AS Faculty of TU Delft is investigated through interviews with stakeholders relevant to ESD implementation. The exploration reveals engagement in both top-down and bottom-up initiatives, such as modifications in the Master program in Chemical Engineering and the implementation of the Green Thread initiative. The faculty has established a Climate Action Team to devise a Climate Action plan, including an educational portfolio, drawing insights from the research conducted.
Twelve influential thematic variables and their associated barriers, drivers, and uncertainty factors are identified through interviews. A focus group SWOT analysis further explores these variables, leading to the development of five strategies (ST1 to ST5) aimed at structuring the education portfolio of the AS Climate Action Plan. These strategies address change direction, context and culture, planning and preparation, design and implementation, and maintaining momentum and sustaining change.
The study concludes by recommending continuous evaluation of the proposed strategies and further exploration of outcomes related to the Climate Action Plan. It acts as a catalyst for discussions within the faculty, promoting broader conversations with the potential to positively impact the AS community.","Education for Sustainable Development; Systems Change; Higher Engineering Education Institutions; Applied Sciences; Education","en","master thesis","","","","","","","","2024-02-27","","","","Industrial Ecology","Education portfolio of the Core Team of Sustainability at TU Delft",""
"uuid:60217add-7c30-4c62-9309-4b6a92349f29","http://resolver.tudelft.nl/uuid:60217add-7c30-4c62-9309-4b6a92349f29","Design and Operation Optimization of Hybrid Energy Systems for a General Cargo Vessel: Well-to-Wake Emission Analysis and Plant Lifetime Estimation","Beeravelli, Arun Datta (TU Delft Mechanical, Maritime and Materials Engineering)","Coraddu, A. (mentor); Polinder, H. (graduation committee); Mylonopoulos, F.M. (mentor); Delft University of Technology (degree granting institution)","2024","The Global Shipping industry is responsible for transporting 90% of global commerce and is responsible for 3% of global greenhouse gas (GHG) emissions. Addressing this, the International Maritime Organization (IMO) aims to reduce GHG emissions from international shipping by 40% by 2030 and achieve net zero by 2050. This study explores Low Temperature-Proton Exchange Membrane Fuel Cell (LT-PEMFC) hybrid energy systems as a potential solution to reduce shipping emissions. Emphasizing the operational zero-emission capability of PEMFC fueled by hydrogen, the research scrutinizes the emission intensity from hydrogen production and the impact of component degradation on hybrid system efficiency and hydrogen consumption.
The research pivots around optimizing the design and operation of ship hybrid energy systems to minimize costs while considering well-to-wake (WTW) emissions and component lifetime. It investigates two hybrid configurations: PEMFC/Li-ion battery (LIB) and Diesel Generator (DG)/PEMFC/LIB. Employing a Mixed Integer Linear Programming approach for component modeling, the study conducts a two-stage analysis: design optimization considering various hydrogen sources and plant lifetime estimation focusing on PEMFC and battery degradation.
Initial findings reveal that system design costs do not significantly differ across hydrogen grades. The DG/PEMFC/LIB configuration emerges as cost-effective, reducing CAPEX by 62.8% compared to the PEMFC/LIB setup. Carbon Capture and Storage (CCS) hydrogen grades strike a balance between cost and emission reduction, notably cutting emissions by up to 85% in the PEMFC/LIB configuration at a 27% OPEX increase.
Lifetime estimation highlights the effectiveness of a hierarchical optimization method in mitigating PEMFC voltage loss and extending component lifespan, albeit with increased battery cycling aging. The study underscores the importance of selecting the appropriate hydrogen grade and operational strategies to enhance the sustainability and economic viability of maritime hybrid energy systems, aligning with IMO’s emission reduction goals.","Proton exchange membrane fuel cell; Li-ion battery; Hybrid Energy System; Mixed Integer Linear Programming (MILP); Optimization; Degradation","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:fd233065-a854-4477-8009-497282dff5b4","http://resolver.tudelft.nl/uuid:fd233065-a854-4477-8009-497282dff5b4","From Scroll to Soul: Design Features of Social Media Platforms and Their Impact on Users' Mental Well-Being","Jaff, Mani (TU Delft Technology, Policy and Management)","de Reuver, Mark (mentor); Marin, L. (graduation committee); Figueroa, C.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","The prevalence of mental health issues among adolescents and young adults is increasing, with social media usage identified as a potential contributing factor. As technology becomes more integral to daily life, the design decisions of social media platforms emerge as significant determinants of users' mental well-being.
Despite awareness of social media's general adverse effects, there is a gap in understanding the specific impact of different design features. Academic literature identifies features like likes and direct messaging as having nuanced effects on mental well-being, but lacks a comprehensive overview for developers to reference. This thesis seeks to bridge this gap, focusing on design features and their psychological impacts to propose design interventions for enhancing mental well-being.
Employing Value Sensitive Design (VSD) as an analytical framework, this study is the first to apply VSD to social media in the context of mental well-being. It involves a tripartite methodology — conceptual, empirical, and technical investigations — to identify significant design features and values related to mental well-being on social media platforms. A novel social media platform, Dime, designed with mental well-being in mind, serves as a case study for evaluating these features and proposing design requirements.
The study identifies 8 key design features affecting mental well-being and outlines 13 values divided into higher and lower levels, facilitating focus on critical values for desired outcomes. It explores value interrelationships and conflicts, particularly noting indirect tensions between values like authenticity and connection, and between personalization, control, and autonomy.
Proposed design interventions aim to resolve identified value conflicts, enhancing authenticity to support connection and enhancing personalization and control to support autonomy.","Social media; Mental well-being; Value Sensitive Design","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:a5e2194b-ddd5-49d0-a7ca-66ecf75af95c","http://resolver.tudelft.nl/uuid:a5e2194b-ddd5-49d0-a7ca-66ecf75af95c","Identification and prioritization of factors and their influence on corporate venturing success: The analysis of influential factors affecting the success of the corporate ventures using the Best-Worst methodology and their prioritization assessment","Gopalakrishnan, Aditya (TU Delft Technology, Policy and Management)","Scholten, V.E. (mentor); Wagner, Ben (graduation committee); Delft University of Technology (degree granting institution)","2024","Corporate venturing practices have been one of the most successful practices in terms of shared innovation or leveraging outside talent to further one’s competitive edge in the rapidly growing and evolving industry of technology. Since, technology has been one of the main driving factors in providing solutions for achievement of short term and long term goals in the space, organizations are interested in finding out potential research findings and data that will enable them to maximize their probabilities of success for the particular venture. Streamlining such points of interest will improve the innovative capabilities of all participating organizations. A repository of literature was combed for identification of key factors that influence success in ventures. For this research BWM methodology has been employed to assess the importance therefore the prioritization of these factors and their impact through a set of curated list of respondents from the industry.","Best-Worst Method; Corporate Venturing; innovation; Extrinsic influencing factors; Intrinsic influencing factors; Open Innovation; Partnerships; Alliances; Port XL; Port Industry; Organizational sustainability goals; Prioritization; Organizational Structures","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:01d5f8ee-1096-4e51-a407-e75973174a89","http://resolver.tudelft.nl/uuid:01d5f8ee-1096-4e51-a407-e75973174a89","Agile risk management: Enhancing the risk management process in projects through agile principles, methods and tools","Liapi, Anastasia (TU Delft Civil Engineering & Geosciences)","Bosch-Rekveldt, M.G.C. (graduation committee); Jalali Sohi, A. (mentor); Hall, Daniel M. (mentor); Delft University of Technology (degree granting institution)","2024","A construction project is inherently complex, involving numerous stakeholders, lengthy timelines, and intricate relationships, leading to significant risk potential. The increased complexity of construction projects and the fact that a large percentage of projects are still delivered with significant delays and cost overruns has led to the necessity of applying different methods by the project managers and the teams. Agile project management is an example of that as its implementation in construction projects can help increase flexibility, achieve continuous improvement, help the project stay on track without schedule overruns and achieve an overall improved quality through effective collaboration and constant feedback. Despite agile project management's flexibility and continuous improvement benefits, its integration with risk management remains underexplored in the construction industry.
The objective of this study is to propose a framework that could help improve the risk management project by offering a more proactive approach and at the same time enhance people’s engagement with risks. The goal of this thesis project is to support construction companies in approaching risk management in a way that incorporates agile methods.
Implemented in a project and evaluated through questionnaires and a focus group, the framework showed promise in elevating risk awareness and fostering interdisciplinary collaboration. However, incomplete implementation of some elements limited definitive effectiveness assessments. Subsequent expert judgment sessions confirmed the framework's potential in proactive risk identification and management, alongside the initial findings of heightened awareness and collaboration. Recommendations for improvement include clearer risk impact depiction and explicit framework objectives communication. Essential for success are targeted risk training, clear vision articulation, and structured step-by-step implementation supported by project managers and risk coordinators.
In summary, the proposed framework merges agile principles with risk management, aiming to cultivate a proactive risk culture, enhance team communication, and mitigate increase engagement with risks. While showing significant benefits, it also highlights the need for adjustments to fully realize its effectiveness in the construction industry's risk management practices. This study underscores the importance of agile methodologies in enhancing traditional risk management approaches, offering insights for future application and refinement.","Risk management; Agile project management; scrum method; Framework development","en","master thesis","","","","","","","","2025-02-26","","","","Construction Management and Engineering","",""
"uuid:36c2f0bd-f1b6-4f72-aabe-211518115aed","http://resolver.tudelft.nl/uuid:36c2f0bd-f1b6-4f72-aabe-211518115aed","Natural User Interface in Augmented Reality to Control Spot: A Large Scale User Study on Speech and Gesture Control of Robots With The Microsoft HoloLens","van der Linden, Jesse (TU Delft Mechanical, Maritime and Materials Engineering)","Eisma, Y.B. (mentor); Delft University of Technology (degree granting institution)","2024","The increasing presence of robots calls for a more seamless and information-rich communication method between humans and robots. This paper explores how natural user interface (NUI) modalities, particularly speech and gesture controls, can be used through augmented reality (AR) to operate robots. The increasing presence of robots calls for proper evaluation methods of how to use AR for operating mobile robots. The study uses the Microsoft HoloLens and the robot, named Spot, from Boston Dynamics as primary technologies. The research consists of a user study consisting of 218 participants, one of the largest participant pools for this field to date. The experiment consists of walking the robot over a trajectory with discrete steps, with the perspective of following the robot or standing on a predetermined stationary point. To support the control of the robot, visual information and feedback are included in the HoloLens. Speech control showed the best time performance of the experiment, regardless of the perspective condition. Conversely, errors made during the trials were the majority for the speech condition, due to the waiting time of the speech recognition that caused participants to repeat the commands. The walking condition gave participants the impression that control commands were more intuitively mapped to the robot's motion. Overall, the participants preferred the speech control method while walking with the robot, and the least preferred method was using gestures in a stationary perspective. Even though the speech was the preferred control method and perspective-taking was preferred by participants, this was only for the experiment and task discussed in this paper. Both control methods have different characteristics that make them favorable to be used for specific tasks. Speech and gestures can be used for different tasks when operating a robot with Augmented Reality glasses; preference will depend on the task at hand and the control method design.","HoloLens 2; Robotics; Augmenetd Reality; Human-Robot Interaction; speech recognition; Gesture Recognition; Teleoperation; Natural User Interface","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:b32a6259-1cb7-4464-becf-ee3a13a8bbf0","http://resolver.tudelft.nl/uuid:b32a6259-1cb7-4464-becf-ee3a13a8bbf0","A Novel Micro-Indentation Based Method for Local Mechanical Property Characterization","Zheng, Qinyi (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Materials Science and Engineering)","Popovich, V. (mentor); Troost, N.C.H. (mentor); Hermans, M.J.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Micro-indentation testing has shown great promise in extracting local mechanical properties of ductile metal materials. Although the relevant contact physics has been well revealed since the 19th century, interpreting the indentation data still poses many challenges at the application level. Regarding one of the mainstream methodologies for extracting metal's representative stress-stain curve, the semi-analytical method has demonstrated remarkable performance towards the well-defined contact system involved. However, applying such a model to other indentation scenarios tends to cause some practical measuring problems. The validity of the results depends heavily on the practical experimental setup and the hardware testing calibration, which is inherently related to its accomplishment level in capturing the entire mechanical response. This thesis investigates such practical issues through a provided semi-analytical model validation. In addition, to capture a material's elastic modulus with less reliance on initial data, a novel analytical model has been proposed, with a special focus on the extensive unloading/reloading data.
However, both the analytical and semi-analytical methods are not fully applicable. For the analytical model, the first unloading segment contributes the most matched estimates of effective modulus to the tensile reference value, with an average deviation error of 6%. But there still remain relatively large discrepancies between two similar samples. Besides, the validity of its results highly depends on accurate profile radius determination, which demands a more precise profilometry system. For the semi-analytical model validation, the resulting indentation strain-stress curves appear to exhibit post-yield behavior and fail to capture the effective modulus as well as the yield strength. It reveals the model's performance that heavily relies on the initial elastic data.","Micro-indentation; Local mechanical characterization; Semi-analytical model; Profilometry; Elastic modulus; Yield strength","en","master thesis","","","","","","","","2026-02-26","","","","Materials Science and Engineering","",""
"uuid:581e4697-0079-4783-bc03-5e2547e0bf11","http://resolver.tudelft.nl/uuid:581e4697-0079-4783-bc03-5e2547e0bf11","Digital twin for dynamic coordination of systems in complex and variable environments: A case study at KLM Engineering & Maintenance","Niers, Jesse (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Transport Engineering and Logistics)","Napoleone, A. (mentor); Negenborn, R.R. (graduation committee); Noble, B.O.M.N. (graduation committee); Delft University of Technology (degree granting institution)","2024","This research investigates the application of a digital twin in managing challenges of variability and complexity within systems by using a case study at KLM Engineering & Maintenance. Using the DMADV (define, measure, analyse, design and verify) methodology, the research evaluates the problem using a literature review, measures and analyses the current state of the Logistic Handling Area (LHA), designs a digital twin concept and verifies its value. The literature review highlights the variability in the Maintenance, Repair and Overhaul (MRO) industry, which enables the investigation of digital twin applications for dynamic coordination. The analysis phase reveals significant operational challenges arising from variability in inflows and processing times, enhanced by system complexity and integral coordination issues between departments. To address these challenges, a digital twin is designed that enables real-time monitoring of KPIs, testing of dynamic resource allocation and integral operational target setting. The value assessment shows that the digital twin can support process operators by managing variability through continuous monitoring and evaluation of resource allocation, ultimately achieving predictable and stable system performance in a complex and variable environment.","Digital Twin; Variability; Complexity; Operation; System; Coordination","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Multi-Machine Engineering","",""
"uuid:aee1e384-e9d4-4d97-9826-51abddeb7b97","http://resolver.tudelft.nl/uuid:aee1e384-e9d4-4d97-9826-51abddeb7b97","Towards a fully distributed multivariable hydrological deep learning model with graph neural networks","Nelemans, Peter (TU Delft Civil Engineering & Geosciences)","Taormina, R. (mentor); Bentivoglio, Roberto (graduation committee); Hrachowitz, M. (graduation committee); Dahm, Ruben (graduation committee); Meshgi, Ali (graduation committee); Buitink, Joost (graduation committee); Delft University of Technology (degree granting institution)","2024","Fully distributed hydrological models take into account the spatial variability of a catchment, and allow for assessing its hydrological response at virtually any location. However, these models can be time-consuming when it comes to model runtime and calibration, especially for large-scale catchments. Meanwhile, deep learning models have shown great potential in the field of hydrological modelling, but a multivariable, fully distributed hydrological deep learning model is still lacking. To address the aforementioned challenges associated with fully distributed models and deep learning models, we explore the possibility of developing a fully distributed multivariable deep learning model by using Graph Neural Networks (GNN), an extension of deep learning methods to non-Euclidean topologies. We develop a surrogate model of wflow_sbm, a fully distributed, physics-based hydrological model, by exploiting the similarities between its underlying functioning and GNNs. The GNN model uses the same input as wflow_sbm: gridded static parameters based on physical characteristics of the catchment and gridded dynamic meteorological forcings. The GNN model is trained to approximate wflow_sbm outputs, consisting of multiple gridded hydrological variables such as streamflow, actual evapotranspiration, subsurface flow, saturated and unsaturated groundwater storage, snow storage, and runoff. Our results show that the GNN model accurately predicts multiple hydrological variables in unseen catchments (median KGE=0.76), and can serve as an emulator of wflow_sbm with a shorter runtime. We furthermore demonstrate how the GNN model can function up to a prediction horizon of a full year, using physical system states to account for system memory, as well as a curriculum learning strategy combined with a multi-step ahead loss function during training. Overall, this study contributes to the field of fully distributed modelling using a deep learning approach.","Hydrological modelling; fully distributed models; Deep Learning; graph neural network; multivariable; surrogate modeling","en","master thesis","","","","","","","","2026-02-01","","","","Water Management | Water Resources Engineering","",""
"uuid:f4b2e90c-373f-4106-ba6f-f832559eca85","http://resolver.tudelft.nl/uuid:f4b2e90c-373f-4106-ba6f-f832559eca85","Deep learning-based Image similarity estimation for geo-localization of Historical Aerial imagery","Liu, Yushan (TU Delft Civil Engineering & Geosciences)","Lindenbergh, R.C. (mentor); Dahle, F. (mentor); Wouters, B. (graduation committee); Delft University of Technology (degree granting institution)","2024","Historical aerial imagery serves as a valuable data source for observing Antarctica, facilitating an extended temporal scale of observation and enabling comparisons to deepen understanding of glacier dynamics. However, many historical aerial datasets, including the Antarctica Single Frames dataset utilized in this study, lack geo-referencing and orientation metadata essential for spatial analysis. One method of geo-referencing these historical images involves image matching to establish Ground Control Points (GCPs). This study focuses on the prerequisite for image matching: ensuring alignment between unreferenced historical images and already geo-referenced images in terms of scene and approximate resolution, a process termed 'geo-localization' herein.
Geo-localization is achieved by comparing the historical image with positions within a predefined geo-referenced Area of Interest (AoI). Two predefined remote sensing datasets are used: Sentinel-2 and Quantarctica Rock Outcrop Mask, from which AoIs are generated. Positions within the AoI exhibiting the highest similarity to the historical image are likely to correspond to the same ground area, thus providing the location of the historical imagery.
This similarity assessment employs two Siamese Networks: SigNet and ResNet-50. SigNet, originally designed for signature verification tasks, consists of four convolutional layers. In contrast, ResNet-50, initially developed for image classification purposes, is characterized by its deep architecture comprising approximately 50 convolutional layers, as suggested by its name. In this study, these two models are initially pre-trained on cross-domain datasets and subsequently adaptively trained with task-specific datasets created in this study. The adaptive training datasets comprise triplets of similar and dissimilar images pre-processed using methods devised in this study. An evaluation methodology based on confidence level is developed to assess the model and workflow performance, which is then applied to 51 test historical image samples.
Overall, the results indicate that the ResNet-50 based network outperforms SigNet, achieving a 95.5% average confidence level. However, the method does not meet the initial expectation of directly providing the location of the historical image within the AoI. Instead, it identifies potential locations. Nevertheless, this outcome is valuable as it streamlines the search process for subsequent image matching steps. For instance, a 95.5% average confidence level for the ResNet-50 based network correlates with an approximate 95.5% reduction in processing time for geo-referencing when integrated with image matching in subsequent steps.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:4987ca25-9510-435e-9673-d1e41804aaf8","http://resolver.tudelft.nl/uuid:4987ca25-9510-435e-9673-d1e41804aaf8","Metal oxide materials for solid-state fluoride ion batteries","Peng, Linhan (TU Delft Mechanical, Maritime and Materials Engineering)","Braga Groszewicz, P. (mentor); Abrahami, S.T. (mentor); Bottger, A.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","This study explores the potential of metal oxide fluorides as cathode materials for solid-state fluoride-ion batteries (FIBs), aiming to combine the stability of intercalation-based electrode materials with the high energy density of conversion-based materials. Through comprehensive experimental investigations using techniques such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), linear sweep voltammetry (LSV), and X-ray diffraction (XRD), the compatibility and electrochemical performance of transition metal oxides (Cu2O, FeO, and Mn2O3) with CsPb0.9K0.1F2.9 (PK10) solid electrolyte and Pb/PbF2 composite anode are evaluated. Results indicate negligible room temperature capacity for Cu2O, FeO, and Mn2O3, suggesting potential limitations related to the cathode fluorination reaction. Additionally, PK10 electrolyte displays slight instability at room temperature, indicating potential electrochemical activity. Symmetric cell testing using Pb/PbF2 composite electrodes confirms the suitability of the Pb/PbF2 composite as both counter and reference electrodes. Notably, Cu2O full cells show enhanced specific capacity at elevated temperatures (60 °C), reaching 310.24 mAh/g during the first cycle, equivalent to 82.96% of the theoretical specific capacity. This considerable increase in capacity due to only a slightly higher temperature is attributed to reduced overpotential and enhanced fluoride ions diffusion rates. However, observation of capacity fade between cycles for the Cu2O cell at 60 °C suggests irreversible reactions, necessitating further investigation. In conclusion, this study highlights the potential of metal oxide cathode materials in solid-state FIBs, emphasizing the importance of understanding electrolyte stability and cathode compatibility for battery performance enhancement.
and adapt, as their assets have to be re-designed to meet the current and future generation needs.
One response to these challenges is adaptive reuse, the transformation of the function of an underused structure into a new use. This process turns the cities’ elements in decline into development catalysers. The adaptation to these changes is often a source of conflict, as urban policies lack citizen engagement in the redefinition of public space, resulting in more disagreement. This is particularly acute when addressing contested communities, as their continuous evolution directly influence the adaptation of cultural heritage.
Considering these aspects, this research question is responded: ‘How can socio-spatial conflicts that result from contested identities be mitigated through the adaptive reuse of urban heritage?’.
The relations between Adaptive Reuse, Urban Heritage and Contested Identities are studied, resulting in the research’s objective: to develop an integrative methodology to evaluate urban heritage adaptive reuse alternatives in contested urban contexts, using the case of Acre (Israel).
This final outcome is proposed as a tool for decision-makers and urban planners that provides information-based results to be applied in urban design practice, aiming to translate the theory into practice, and to bridge the gap between global goals and local issues.","Adaptive reuse; urban heritage; conflict; urban resilience; Acre; Israel","en","doctoral thesis","A+BE | Architecture and the Built Environment","978-94-6366-825-5","","","","","","","","","Heritage & Architecture","","",""
"uuid:4757b9fd-580d-41c2-92ed-768a1a50189a","http://resolver.tudelft.nl/uuid:4757b9fd-580d-41c2-92ed-768a1a50189a","Observing human gait and detecting falls: A model-based approach based on wearable sensors","Umans, Sachin (TU Delft Mechanical, Maritime and Materials Engineering)","Keviczky, T. (mentor); Poggensee, K. (mentor); Vallery, H. (mentor); Delft University of Technology (degree granting institution)","2024","Falling remains a large source of (traumatic) injuries and healthcare costs. Over the past years, different actuators have been developed in the field of wearable robotics to help prevent injuries from falling. To increase the wearability of these systems, the weight of power storage can be decreased with intermittent instead of continuous control. A fall detector is then needed for these systems to trigger the activation of the actuator to prevent the fall. A proof of concept for a model-based fall detector that is aimed at using only wearable sensor measurements is presented. The algorithm is based on a single inertial measurement unit placed on the lower back. The upper-body orientation and centre of mass velocity are estimated with two separate Kalman filters. The velocity is estimated with a gait model consisting of a spring-damper-legged point mass in three-dimensional space. The balance of the subject is evaluated with the velocity estimates and the extrapolated centre of mass method. The presented model is verified on a non-falling treadmill walking dataset of real humans and shows accurate estimates of the centre of mass velocity. Furthermore, a planar falling simulation is performed to show successful pre-impact fall detection. This resulted in no false alarms outside the initial estimation settling time, and a successful detection with a lead time of 680 ms. This lead time is long enough to provide a trigger for fall mitigation devices.","Fall detection; pre-impact; wearable sensor; model-based; gait; robot-assisted fall recovery","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:7cb83925-fdc2-49f6-96c2-560c40f61519","http://resolver.tudelft.nl/uuid:7cb83925-fdc2-49f6-96c2-560c40f61519","Evaluating the impact of prediction accuracy on Continuous Descent Operations: The added value of Trajectory Predictor performance through Air-Ground Datalink","Raghunandan, Mithun (TU Delft Aerospace Engineering)","Hoekstra, J.M. (mentor); Ellerbroek, Joost (graduation committee); Dijkstra, Ferdinand (graduation committee); Delft University of Technology (degree granting institution)","2024","This research investigates the role of time prediction accuracy in optimizing Continuous Descent Operations (CDO) within the aviation sector, with a specific focus on assessing the additional benefits brought forth by the integration of Air-Ground Datalink technologies. Continuous Descent Operations, characterized by uninterrupted and efficient descent profiles, hold promise for reducing fuel consumption, emissions, noise, and overall operational costs. However, the extent to which accurate time predictions contribute to the success of CDO remains a critical yet understudied aspect.","Continuous Descent Operations; Trajectory Prediction; Extended Projected Profile (EPP); ADS-C; ATN-B2","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:16494021-9bd2-4089-8808-5ad9dffadc5d","http://resolver.tudelft.nl/uuid:16494021-9bd2-4089-8808-5ad9dffadc5d","The impact of third generation sequencing on haplotype assembly","Shirali Hossein Zade, R. (TU Delft Pattern Recognition and Bioinformatics)","Reinders, M.J.T. (promotor); Abeel, T.E.P.M.F. (promotor); Delft University of Technology (degree granting institution)","2024","The genome encompasses an organism’s full DNA, organized into chromosomes within the cell nucleus. Humans have 46 paired chromosomes, and within these pairs, genetic information is grouped as haplotypes—genetic packages passed from one generation to the next, ensuring genetic diversity. While DNA sequencing produces short fragments or reads, assembling these back into a complete genome can be complex. The presence of multiple, similar haplotypes in some organisms amplifies this complexity, emphasizing the need for specialized techniques to accurately capture these subtle genetic variations.
In this thesis, we dive into the de novo and haplotype assembly challenges. We aim
to tackle haplotype assembly challenges and find better ways to accurately assemble the genetic puzzle pieces. Along the way, we introduce a new tool for haplotype assembly designed to make the process more interpretable.","Haplotype assembly; Genome assembly; Third generation sequencing; Genome repeats","en","doctoral thesis","","978-94-6384-539-7","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:23da15d6-893c-4d56-984b-e56077f70b68","http://resolver.tudelft.nl/uuid:23da15d6-893c-4d56-984b-e56077f70b68","In-Flight Nitrogen Oxide Measurements for Different Settings of a Lean Burn Engine","Stremming, Luca (TU Delft Aerospace Engineering)","Grewe, V. (mentor); Gangoli Rao, A. (graduation committee); Yin, F. (graduation committee); Bräuer, Tiziana (graduation committee); Delft University of Technology (degree granting institution)","2024","Aviation is an important contributor to anthropogenic climate change. As indirect greenhouse gases, nitrogen oxides (NOx = NO + NO2) add to the Effective Radiative Forcing (ERF) induced by aircraft emissions. This work addresses a better understanding of emission mitigation by investigating dependencies between engine parameters and emitted nitrogen oxides as a part of the campaign VOLCAN. In-flight near field measurements are conducted using the DLR research aircraft Falcon, chasing an Airbus A321neo equipped with CFM LEAP-1A engines featuring lean combustion through staged fuel injection. Nitrogen oxide concentrations are measured applying the well-established chemiluminescence method. Emission indices are quantified for different fuels including Jet A-1, Sustainable Aviation Fuel (SAF) and two SAF blends with different levels of aromatics. Four combustor inlet temperature settings are tested and staged (lean) combustion is compared to unstaged (rich) combustion. Emissions are measured for two different but technically identical engines, deviating in terms of exhaust gas temperature margin. As expected, results indicate no significant differences in emitted nitrogen oxides for the investigated fuels. Measurements confirm that nitrogen oxide emission indices increase exponentially with combustor inlet temperature. Due to the forced nature of the analyzed rich burn mode, a reduction in nitrogen oxide emissions through lean combustion cannot be confirmed. Based on presented data, a relationship between engine degradation and nitrogen oxides is likely. Near field observations agree with well-established far field measurements and lead to lower uncertainties. Preliminary results of the ECO-Demonstrator campaign are in line with VOLCAN measurements. The performed research is a highly valuable contribution to extremely rare empirical in-flight emission data. Established nitrogen oxide dependencies support technical decision making to reduce aviation’s climate impact.","Nitrogen Oxides; In-Flight Measurements; Sustainable Aviation Fuels; Aviation; Combustion; Lean Burn Engine","en","master thesis","","","","","","","","2026-02-26","","","","Aerospace Engineering | Flight Performance and Propulsion","VOLCAN",""
"uuid:fa98318c-0b56-4d15-a71e-bae82432316c","http://resolver.tudelft.nl/uuid:fa98318c-0b56-4d15-a71e-bae82432316c","Wind turbine main bearing degradation monitoring using physics-based analysis of SCADA data","Mammadov, Ilkin (TU Delft Electrical Engineering, Mathematics and Computer Science)","Zappalá, D. (mentor); Eftekhari Milani, A. (mentor); Delft University of Technology (degree granting institution)","2024","The main bearing is a critical wind turbine drivetrain component, and its failure can cause the turbine shutdown and expensive repair. As the main bearing degrades, its temperature increases, indicating health deterioration of the component. Various methods proposed in the literature employ physics-based normal behavior models (NBMs) using Standard Supervisory Control And Data Acquisition (SCADA) data as input to energy conservation-based equations to model the main bearing temperature. These methods analyze the difference between the measured and the modeled temperature, referred to as residual. These residuals are used as health indicators (HIs) for assessing the condition of the component.
Physics-based NBMs utilizing SCADA data have been successfully used for fault detection of the main bearing. However, the application of these methods for degradation trend monitoring have not yet received attention. The primary reason for the premature failure of wind turbine components is attributed to the variability of the wind conditions. However, current NBM methods are based solely on the mean value records and do not consider the variations within the 10-minute time frame. Furthermore, seasonal fluctuations in operating conditions can adversely affect the obtained degradation trend.
The main objective of this thesis is to improve physics-based NBM employing SCADA data to monitor the degradation trend of the main bearing. The proposed approach uses a physics-based NBM available in the literature as the baseline. It aims to increase the monotonicity and reduce the dispersion of the developed HI to enable accurate degradation trend monitoring. To achieve this objective, the proposed method takes into account seasonal variations and variability of operating conditions within the 10-minute SCADA time frame when modeling the main bearing temperature. To mitigate the impact of seasonal changes on the HI, the proposed method develops multiple physics-based NBMs corresponding to monthly time windows. To take into account the variability of the operating conditions, the main bearing temperature is modeled by performing a Monte Carlo simulation using the SCADA data mean and standard deviation values. In this case, the HI is defined by the data density within a threshold region. Two case studies are conducted to demonstrate the advantages of the proposed method compared to the baseline approach. The results show that with the proposed approach, the seasonality effects are reduced by more than 50%, as measured through cross-correlation metric with the ambient temperature, the HI monotonicity increases by 260% as measured by the Mann-Kendall τ monotonicity metric, and the dispersion reduces by 30% and 35%, as evaluated by the Mean Square Error and a noise metric obtained using the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise approach.","Physics-based NBM; Health Indicator; Degradation; Main Bearing; SCADA; temperature","en","master thesis","","","","","","","","","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:48078884-e157-4c0c-9fc3-01c0caaebb56","http://resolver.tudelft.nl/uuid:48078884-e157-4c0c-9fc3-01c0caaebb56","Implementing an Adaptive Haptic Shared Controller in Pursuit and Preview Tracking Tasks","Mckenzie, Max (TU Delft Aerospace Engineering)","Mulder, Max (mentor); van Paassen, M.M. (mentor); Borst, C. (graduation committee); Ribeiro, M.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Haptic shared controllers (HSCs) are a promising solution to prevent human over-reliance on automation during tasks such as car driving. However, research has shown that if the HSC is tuned incorrectly, then there is a risk of haptic conflicts between the human and HSC. To address this challenge, this paper presents the design and implementation of a novel adaptive HSC that continuously adjusts its look-ahead time. By estimating the time shift between the reference state of the HSC and the actual state, the HSC adapts to the look-ahead time of the human it is interacting with. Results from a human-in- the-loop experiment show that the novel HSC achieves similar subjective ratings as a fixed preview HSC, as well as a significant improvement over a fixed pursuit HSC. Going from pursuit to preview, objective experiment data shows that as the adaptive HSC adjusts its look-ahead time, haptic conflicts are reduced and tracking performance is increased. The presented findings are a step forward in designing haptic support systems with high chances of user acceptance. The proposed adaptive look-ahead algorithm provides a new method for online estimation of human look-ahead time, with or without a HSC in-the-loop.
The cases' workshop activities were structured into seven phases: preparation, information, function analysis, creative, evaluation, development, and presentation. The governance mechanisms used included coordination, building-capability, goal-setting, monitoring, and roles & decision-making. Based on both theoretical and empirical results, the developed project governance process involves several workshop activities and governance mechanisms, where value is defined in terms of impact and then working backwards through a multi-phase process. The process is divided into the following phases: usefulness & necessity phase, preparation phase, information phase, outcome and impact analysis phase, creative phase, evaluation phase, development phase, and presentation and reporting phases. A visual representation of this process can be seen in Figure 4.1 in the original document. Once developed, a workshop confirmed its feasibility for implementation because all phases were clearly explained. Experts' recommendations included linking these phases with work packages, conducting risk analysis before the ""creative phase,"" and making it more visually appealing through a flowchart full of icons or colors to help technical actors better understand it and thus make it more practical.
Integrating the benefits management and value engineering approaches can be achieved by incorporating them into the already-established value engineering multi-phase process. This requires considering all scales along which value evolves, starting from impact, and evaluating them once identified. By doing so, actors are equipped to take more parameters into account, mitigating the uncertainty between expected and realized value. Additionally, governance mechanisms play a crucial role in aligning all actors' expectations towards achieving high-value goals by bringing them together towards a shared goal.","Value engineering; Benefits management; Value Creation; Front end; governance mechanisms","en","master thesis","","","","","","","","","","","","Construction Management and Engineering","",""
"uuid:3d0c2e76-2016-4db3-9f1a-df4ae62f76b9","http://resolver.tudelft.nl/uuid:3d0c2e76-2016-4db3-9f1a-df4ae62f76b9","Towards a measurement-based approach to estimate farm-specific ammonia emissions: With feed management parameters and the slurry manure composition as indicators of the AEP","van Hamel, Emiel (TU Delft Technology, Policy and Management)","Erisman, Jan Willem (mentor); Mogollón, José (mentor); Delft University of Technology (degree granting institution); Universiteit Leiden (degree granting institution)","2024","The research focuses on a novel measurement-based approach to estimate the farm-specific ammonia emission potential (AEP) in the dairy sector. By measuring and evaluating the feed-manure chain, feed management strategies and manure parameters influencing AEP can be identified. Ammonia emissions from dairy farms are not only considered to be an important driver of biodiversity loss, but are also responsible for nutrient losses in the farm cycle. Currently, farm-specific ammonia emissions are calculated using the Kringloopwijzer model, which tends to over- or underestimate actual ammonia emissions. Therefore, the possibilities of a measurement-based approach are evaluated.
This study analyses the relationships within the feed-manure-AEP sequence. A comprehensive approach is used, involving 23 manure parameters and 12 feed management parameters. The most important predictors of the AEP include N, TAN, Norg, N90, and the C/N ratio, whilst urea in milk, pH, and DS showed low significance. Silage maize and VEM are identified as feed management parameters with a positive indirect relationship with the AEP, whereas other roughage and fresh grass exhibit a negative indirect relationship. The calculated TAN value plays a central role in the emission calculations of the Kringloopwijzer model. There are concerns about the accuracy of this value as well as the absence of other manure parameters in the calculation, highlighting the need for further research. Currently, it is uncertain whether the AEP measurements will be suitable for an emissions-based policy, due to the incapacity to directly represent actual ammonia emissions and the uncertainty regarding the interpretation of the results caused by the period prior to the measurements. Nonetheless, the measurements are valuable in assessing the influence of the manure composition on the AEP, and how it has been affected by feed management strategies.","dairy farming; Ammonia; Manure","en","master thesis","","","","","","","","","","","","Industrial Ecology","",""
"uuid:46353baa-6b74-4c92-a454-7d11d5fa30aa","http://resolver.tudelft.nl/uuid:46353baa-6b74-4c92-a454-7d11d5fa30aa","Automatic Tuning Saxophone Mouthpiece","Zhang, Yifan (TU Delft Electrical Engineering, Mathematics and Computer Science)","Langendoen, K.G. (mentor); Venkatesha Prasad, Ranga Rao (graduation committee); Delft University of Technology (degree granting institution)","2024","Saxophone is a musical instrument that tends to be out of tune. I have invented an automatic tuning saxophone mouthpiece that can help saxophonists play in tune by correcting their notes' frequencies in real time during performances using a stepper motor.","Music; Saxophone; Tuning; FFT; Frequency detection","en","master thesis","","","","","","https://www.youtube.com/watch?v=-isqbL49Cvc Demonstration video of the Automatic Tuning Saxophone Mouthpiece","","","","","","Electrical Engineering | Embedded Systems","",""
"uuid:aec205b3-a5d0-4f6c-816c-6ac4c172cff1","http://resolver.tudelft.nl/uuid:aec205b3-a5d0-4f6c-816c-6ac4c172cff1","Empowerment Through Customization: System of Tools to Present NAVii® Protective Cover to Users and CPOs","Franco, Laura (TU Delft Industrial Design Engineering)","Xue, H. (mentor); Filippi, M. (graduation committee); Harðardóttir, Sigríður (mentor); Delft University of Technology (degree granting institution)","2024","Prosthetic limbs are devices that change users’ lives in every aspect. They allow the wearer to live and be independent again. Nevertheless, despite the numerous benefits, they carry cultural stigmas, as well as physical and mental discomfort, along with various daily challenges. While the functionality and physical comfort of these devices can be objectively evaluated using instruments with differing levels of sophistication, assessing psychological well-being is highly subjective and challenging.
It is known that the aesthetic of prosthetic limbs can have a significant impact on the users’ wellbeing. Research demonstrated that an aesthetically appealing prosthesis can improve user confidence and overall quality of life (Össur® systematic Review, 2022). It can promote a positive self-image and a more active involvement in society (Bekrater-Bodman, 2020), reduce the risk of anxiety, depression, and psychological distress and increase the frequency of use of the device (Lee at al., 2022). In this scenario customization emerges as a viable approach empowering prosthetic users to improve their life and the embodiment with their prosthetic limb.
This thesis has been conducted in collaboration with the prosthetic company Össur®. The project revolves around NAVii®, a new protective cover designed for the knee component of transfemoral prosthesis. For the first time, NAVii®’s users will be able to customize their prosthetic limb by choosing between five different colors and three available sizes. Össur® is now looking into the modalities by which these customization options can be presented to the market. The focus is on the main stakeholders: the prosthetic Users and the specialists Certified Prosthetist/Orthotist (CPOs). The project takes a user-centered design approach that aims to a deep understanding of the users, the context and the current system’s dynamics. By applying qualitative research methods such as interviews, focus group and observation the goal is to improve the whole user experience during the selection of the NAVii® cover.
This research highlighted the impact of the different CPOs on the journey of each patient. Even though every user goes through a subjective amputation experience, it is possible to identify common touch points throughout the prosthetic acquisition process. The final design is the result of an iterative process of concepts’ prototyping and testing. The findings obtained from the testing lead to the development of a system of tools that aim to support the CPOs and the users in the selection of the NAVii® protective cover. This new design system, is able to suit diverse user’s needs. The design outcome yielded positive impacts on the user’s psychological empowerment, consequently enhancing the CPO-User relationship.","Prostheses; Customization; Empowerment","en","master thesis","","","","","","","","","","","","Design for Interaction | Medisign","",""
"uuid:ce61e261-b48a-4988-b2df-b7065837ba2b","http://resolver.tudelft.nl/uuid:ce61e261-b48a-4988-b2df-b7065837ba2b","Bistable Interlocking Mechanism in SHCC-to-SHCC Interfaces: An Experimental Study","Papoulidou, Sofia (TU Delft Civil Engineering & Geosciences)","Lukovic, M. (mentor); Šavija, B. (graduation committee); He, S. (mentor); Delft University of Technology (degree granting institution)","2024","The current structural demands include complex designs, efficient utilization of material resources, and maintenance of existing structures and infrastructure. In all these cases, the connections between structural components are the main focus of design since they are widely considered the weakest link in a structural system. The demand for strong and durable connections with cementitious materials is higher than ever. Creating reliable connections is largely connected to material reuse, waste reduction, ease of disassembly, and the ability to extend the life cycle of structures. These principles contribute to a more sustainable approach to construction.
Recent research shows that by implementing intricate interlocking geometries, toughness can be added to inherently brittle materials like ceramics or polymers. With the concept of ""toughness by segmentation,"" new metamaterials emerge with enhanced properties compared to the monolithic material they are made of. In this study, the focus is on bistable interlock, a new type of connection. Inspired by nature, the connection is based on double-radii morphologies that geometrically lock into two equilibrium positions under tensile load, exhibiting two distinctive peaks in their force-displacement diagram. When the bistable interlock mechanism was applied to Acrylonitrile Butadiene Styrene (ABS), a relatively brittle yet strong polymer, the sutured material was up to 10 times tougher than monolithic ABS. The focus of this research is to manufacture the bistable interlock mechanism with cement-based materials and specifically, Strain Hardening Cementitious Composite (SHCC). SHCC belongs to the category of fiber-reinforced concrete and is distinguished by its tensile hardening behavior and pseudo-ductility stemming from its fiber-bridging property. Combined with the geometrical hardening of bistable interlock, the ultimate goal is to create resilient connections that balance toughness and strength.
The performed literature study was focused on three areas: the bistable interlock mechanism, interfacial load transfer mechanisms in concrete-to-concrete interfaces such as friction, chemical bond, and mechanical interlock, and the material and mechanical properties of Strain-Hardening Cementitious Composites (SHCC).
Two main areas of interest were the objects of the experimental study. The first was to understand the tensile behavior of bistable interlocks, and the second was to optimize it by appropriately tailoring the interface and geometry. The design of the experiments featured three parameters: the key shape (straight & curved keys), the interface treatment (untreated & lubricated interface between the two parts), and the geometry (based on width-to-height ratios for straight keys & radii ratios for curved keys).
From the experimental results, it was found that the shape of the keys changed the tensile response of the specimens greatly. The influence was different for untreated and lubricated interface specimens. For the untreated specimens, the complex shape of the bistable interlocked geometry combined with interface adhesion led to 78% of the untreated specimens rupturing at the interface. Only 44% of the straight keys showed failure under the same conditions. In this application of bistable interlock, no benefits of geometrical hardening could be exploited due to the strong adhesive bond causing premature failure of the keys at the interface. For the lubricated specimens, shifting from straight to curved geometry brought simultaneous increases in force and energy (i.e. defined as the area under the force-displacement diagram) for all the specimens, fully exploiting the benefits of the frictional contact of the bistable interlock mechanism. The increase in force documented ranged from 41-62% and in energy from 9–96%.
The aforementioned difference in tensile response highlights that the interface treatment is a governing parameter. Only 56 and 22% of untreated straight and curved specimens fully delaminated (e.g. instead of breaking) in comparison to 89% of their lubricated equivalents. The rest of the specimens exhibited (localized) SHCC failure due to the strong interface bond. Untreated specimens showed a higher resistance force (approximately 20% for straight and 10% for curved keys) but a more brittle response, resembling a monolithic connection, while lubricated specimens showed less resistance to tension, resembling a sliding connection. This trend is consistent with broader findings in the literature: inherently brittle monolithic materials compared to their architectured counterparts exhibit greater strength but lower toughness. For the straight keys, lubrication made the failure mode more uniform but decreased the strength and energy. The strong bond of untreated specimens, accompanied by a hardening response due to fiber activation against torsion and/or bending, was responsible for this result. Specimen imperfections caused this state of combined loading. Curved lubricated keys showed an enhancement in energy absorption (i.e. area under the force-displacement diagram) due to the exploitation of the bistable interlocks. Special curved keys made of assembled parts were investigated, simulating a precast-to-precast connection. The assembled keys did not outperform the lubricated and untreated curved keys in terms of strength and energy absorbed. Their benefits lie in two areas: they were easier to manufacture, and they attained a larger second peak than the first in the force-displacement diagram. This characteristic is beneficial for the mechanical stability of the system.
To optimize the response, the specific geometry of the specimens was analyzed (w/h and 𝑅1/𝑅2). The influence of the geometry on the tensile response was not as prominent as the interface treatment. However, improvements were noticed when increasing geometry parameters. For untreated and lubricated straight keys, increasing the length led to a proportional increase in absorbed energy but not in strength. For the curved untreated specimens, the increase in geometry yielded no major differences since the interface treatment governed the response. Conversely, for the lubricated specimens, with a geometry increase, the response was enhanced in both strength and energy and eventually, a design threshold at 𝑅1/𝑅2 = 1.10 was noticed. A clear trend of an increase in the first peak, and a decrease in the second peak as the geometry increased, existed. Extensive cracking and loss of stiffness after the second equilibrium position due to the geometrical interference of larger keys were responsible for that.
Overall, the architectured SHCC material, straight or curved, attained 1/3 of the strength of the monolithic SHCC. This was even lower for lubricated keys. When it came to energy absorption, the lubricated curved keys with bistable interlocks performed better, reaching up to 75% of the SHCC’s energy. This is contrary to the literature findings, where bistable interlocked materials made of ABS were tougher than monolithic ABS. In the case of SHCC, the material properties were different. Due to the extensive cracking of the key, reduced frictional contact occurred, and reduced energy was absorbed. However, a beneficial characteristic of the architectured SHCC keys was their sustained resistance to tension at higher strain levels. That makes them beneficial for many engineering applications where energy absorption and resistance to impact loads and thermal and/or hygral effects are prioritized. Another benefit exists in the customization of their tensile response by fine-tuning geometrical parameters. For a radii ratio of 1.10 in bistable interlocked keys, a satisfactory balance of strength and toughness was achieved, showing that with appropriate design, the connections have promising results.","Bistable Interlock; Strain-Hardening Cementitious Composite (SHCC); Architectured Material; Interface; Ductility; Geometrical Hardening","en","master thesis","","","","","","","","","","","","Civil Engineering | Structural Engineering | Concrete Structures","",""
"uuid:dc75e4b8-356e-4ce5-bbd0-7a672c5ae394","http://resolver.tudelft.nl/uuid:dc75e4b8-356e-4ce5-bbd0-7a672c5ae394","Electronic quality factor control for piezoelectric transducer arrays","Wemelsfelder, Tom (TU Delft Mechanical, Maritime and Materials Engineering)","Lopes Marta da Costa, T.M. (mentor); Delft University of Technology (degree granting institution)","2024","In recent years, many therapeutic applications for medical ultrasound have arisen, such as ablation of tumors, breaking up kidney stones, and neuromodulation. To localize the target area, often ultrasound imaging methods are used. Conventionally, a different transducer array is used for imaging and therapeutic applications because of their conflicting requirements of transducer damping. If this damping would be done electronically, it can be switched on or off on demand, allowing a single transducer array to be used for both therapeutic and imaging ultrasound. This would allow medical ultrasound devices to be smaller and therapeutic treatments to have reduced overall system complexity. This thesis develops a PCB to compare a combination of existing and novel methods of electronic damping on a single transducer, also called electronic Q-factor control. A maximum damping of 23\% is achieved relative to the undamped transducer mounted on the PCB. This is achieved by a novel method based on a feedback loop around a second 'dummy' transducer. Methods of electronic Q-factor control should eventually be extended to be applied in an Integrated Circuit for damping of entire ultrasound transducer arrays.","Ultrasound Imaging; ultrasound neurostimulation; Ultrasound Transducer; Piezoelectric; Q-factor; Quality factor; Neuromodulation","en","master thesis","","","","","","","","2026-02-23","","","","Biomedical Engineering","",""
"uuid:17b83ad6-3179-4a10-8194-90c4e6c768b2","http://resolver.tudelft.nl/uuid:17b83ad6-3179-4a10-8194-90c4e6c768b2","Printed spark ablation nanoparticle films for microelectronic applications","van Ginkel, H.J. (TU Delft Electronic Components, Technology and Materials)","Zhang, Kouchi (promotor); Vollebregt, S. (copromotor); Delft University of Technology (degree granting institution)","2024","This thesis is about the application and characterisation of spark ablation generated nanoparticles in microelectronics. It opens in chapter 1 with a general motivation of the need for advanced materials and for nanotechnology in particular. It then describes what nanoparticles are and why they are promising materials. Some of their advantages are a high chemical reactivity, a high specific surface area, and the display of quantum effects at that scale. The chapter ends by presenting the research questions and giving the thesis structure.
Chapter 2 provides a technological background for the rest of the thesis based. It describes several applications of nanoparticles within microelectronics not researched during this PhD project: as die-attach materials, chemical sensors, or catalysts. It continues with the description and discussion of several competing nanoparticle synthesis methods and goes in-depth on the theory of spark ablation generation. It describes the effects of various parameters that govern the mass generation rate, particle size, and composition. This theory is important to be able to interpret the results in the other chapters. Impaction deposition is then described in this chapter since it is the method of printing all samples in this thesis. It explains how this method prints dots or lines of nanoparticles, that they have a Gaussian cross-section profile, and how specific deposition parameters affect the deposit. Lastly, the chapter gives a detailed description of the spark ablation synthesis and deposition equipment with which all the experiments in this thesis are performed. The generator, components, gasses, pressures, and materials are all described with diagrams and specifications. Typical synthesis and deposition settings for the generation of Au nanoparticle deposits are given (1 kV, 5 mA, 1.5 L min.¡1 Ar or N2 and 1mmnozzle distance).
The first chapter with results, chapter 3, presents a method to measure the mass deposition rate of the nanoparticle printer. Measuring the mass of microgram scale deposits is challenging due to the high sensitivity required for an accurate measurement. Balances are sensitive to changes in pressure, temperature or humidity that can already give too big errors. One solution already applied in thin film deposition methods is the use of quartz crystal microbalances (QCMs). Their resonance frequency is dependent on their mass, and thus, we can use the frequency shift during deposition to measure a mass change. The Sauerbrey equation that is used for that conversion must be valid, so a special method was developed to comply to all of its conditions. A concentric circular pattern of Au nanoparticles was printed on 10 MHz QCMs to measure the mass deposition rate. It was found that the deposition rate scales linearly with the generation current of the spark, as expected from theory, but also showing the losses in the system are either constant or scale linearly too. The film density was surprisingly constant for all tested synthesis and deposition settings, at 15.95 g cm¡3, or a porosity of £p Æ 0.18. The density was compared to models presented in literature, and it is proposed that the impaction energy likely compacts the porous structure during deposition until this density is reached. The QCM method can be applied for process monitoring using commercially available equipment and open-source software.
The first applications of printed conducting nanoparticle films are discussed in chapter 4. It describes the conductive properties of such films and the effect of annealing on their conductivity. It was found that an untreated Au film conducts 22 times worse than bulk Au. Several applications are then discussed. Here it was demonstrated that printed Au nanoparticle lines can be applied as interconnect materials as an alternative to wire bonding. Next, a method was presented to miniaturize the deposits even further by using lithography and lift-off. This reached a line width at the minimum of the lithography equipment available, at 1.2 ¹m, without significantly changing the nanostructure.
Chapter 5 deals with the application of spark ablation generated nanoparticles as thermoelectric materials. It describes in detail the synthesis and characterization of Bi2Te3 nanoparticles and their thermoelectric properties. The main finding was that the thermal conductivity was drastically lower than bulk Bi2Te3 and comparable to the state of the art for Bi2Te3 nanostructured materials, reaching a minimum of 0.2Wm¡1 K¡1 at room temperature. Unfortunately, the electrical conductivity was reduced by at least a factor 1000, easily undoing any efficiency gains from reduced thermal conductivity. Suggestions are given to possibly improve this trade-off. Additionally, this chapter shows how quickly nanostructured materials like the ones in this thesis oxidize after synthesis. From the moment the sample is printed, it gains mass and loses conductivity, so this must be counteracted if a non-noble metal is to be applied.
The final chapter before the conclusions, chapter 6, showcases another application of printed nanoparticles: as UV-sensing material. It shows the results obtained using ZnO nanoparticles to create a UV sensor that is insensitive to visible light. The nanoparticles were deposited over electrodes to fabricate a resistor that has two orders of magnitude electrical resistance reduction when exposed to 265 nm UV light. The response was slow, with 79 seconds to reach 90% of the maximum response and 82 seconds to get back to 10% again. This is attributed to the adsorption and desorption of oxygen under the influence of UV light and can be prevented by packaging the sensor. The contact behaviour between the metal electrodes and ZnO nanoparticles proved to be too unpredictable to reliably create a Schottky diode, which would have had a higher response. This dissertation ends with a list of the conclusions, the answers to the research questions, and finally, some suggestions for future work.
2 emissions [89]. The goal of the circular built environment is to minimise waste by reducing, reusing, recycling, and recovering materials throughout the life cycle of a product [66]. Therefore, making an impact in the construction industry can lead to a significant reduction in CO2 emissions and contribute to the achievement of the European Green Deal [46].
This research contributes to the ""reuse"" component of the aforementioned circular built environment goals. Specifically, the focus is on developing a reusable connection between hollow core slabs and steel frames by implementing increased execution tolerances. Increased tolerances are necessary to allow reuse, as alignment-related problems often occur. The research consists of several parts: the design process, structural verification, experimental research on demountability, and environmental impact assessment. The design process comprises a tolerance analysis supported by a Monte Carlo simulation, variant studies, and a comprehensive qualitative trade-off analysis. After the best scoring alternative is determined, the verification part assesses the structural behaviour of the connection in terms of strength and stiffness. This is done using a combination of analytical and numerical calculations. The purpose of the experimental research is to investigate the demountability potential of the reusable connection. The final part of the research investigates the impact of the reusable connection compared to conventional connections for different lifecycle scenarios.
The research demonstrated that incorporating additional tolerances in the connection between the hollow core slab and steel frame is crucial to achieve a reusable construction. Three connection alternatives were generated that can incorporate these tolerances based on a literature review and meetings with experts in the field of building construction. The alternatives were weighted on tolerance inclusion, ease of installation, demountability potential, and costs. The best option was identified as a connection consisting of a square hollow section and a bolted shear stud encased in mortar. This alternative outperformed competitors in terms of tolerances, installation, and costs. However, the demountability potential was identified as a critical part of the connection and, therefore, was further investigated experimentally. The experiments showed an increased demountability potential in situations that include pre-treatment. Vaseline-treated specimens showed no signs of chemical bonding and better lubrication compared to oil-treated specimens, resulting in the lowest resistance and, therefore, the best demountability. The last step of the research investigated the environmental impact of the reusable connection and compared it with the conventional construction technique. Results showed that a marginal addition of 1.3% to the initial environmental impact of the superstructure results in a significant reduction over the full lifespan of the structural elements. This was attributed to the reusability of the connection and the ability to reuse structural elements in another building in a second life cycle.
From the results, it is concluded that a reusable and structurally feasible connection between hollow core slabs and integrated steel beams can be created with a small additional investment upfront, resulting in a substantially reduced environmental impact. The purpose of this study is to provide guidance and persuade decision makers, such as project developers, building owners, and government organisations, to consider implementing reusable construction methods in their real estate projects. By doing so, they can contribute to the objective of the European Green Deal [46] policies and the goal of achieving net-zero greenhouse gas emissions by 2050.","Reusable; Hollow-core slab floor component; Steel frame; Monte Carlo simulation; Execution tolerances; Environmental Impact Assessment; Connection design; Trade-off Analysis","en","master thesis","","","","","","","","","","","","Civil Engineering | Environmental Engineering","",""
"uuid:4bd4dc86-e55a-4c48-89c7-59d3f666c7ee","http://resolver.tudelft.nl/uuid:4bd4dc86-e55a-4c48-89c7-59d3f666c7ee","Integrating cognitive user data in journey maps: Explorations towards designer affinity","Bhamidi, Sreeniza (TU Delft Industrial Design Engineering)","Bourgeois, Jacky (mentor); Schneegass, C. (graduation committee); Delft University of Technology (degree granting institution)","2024","User-centric design practice rely on journey maps and personas as a way to communicate user needs to the design team (Lanius et al., 2021). However, journey maps in practice have been found to lack a dimension that could inform designers about intrinsic cognitive needs of the user. This research project aims to address this gap by exploring ways to make human cognitive data designer-friendly. Through multi-study approach, including the Research through Design (RtD) (Godin & Zahedi, 2014) method, the study investigates dimensions of the relationship between designers and cognitive user data to make it easy-to-approach in future.
Following the context exploration studies, designers' perspectives and practices regarding cognitive user data are delved into. Findings from exploratory interviews reveal varied interpretations of cognitive data, challenges in accessing and visualizing data, and a keen interest in its potential benefits for design processes. Designers identify time constraints as a major hurdle but express enthusiasm for the posterity and revisiting advantages of effective cognitive data visualization.
The RtD method helps in investigating a way of presenting holistic data to designer that merges intrinsic and extrinsic factors of the user. Designers favor clarity, interactive exploration, and reliability in data presentation. The study provides a comprehensive list of neurophysiological measures that can aid designers in decision-making. Additionally, insights into designers' thinking styles, distinguishing between big-picture and detail-oriented thinkers, add a nuanced layer to understanding their affinity with cognitive data.
The report acknowledges limitations, including biases in the Research-through-Design method, reliance on self-reported data, and the controlled environment of prototype evaluations. Future research is encouraged to address these limitations and enhance the ecological validity of findings.
In conclusion, this research offers valuable insights into integrating cognitive user data within designer practices and establishes a way of integrating observational data with user journey maps. The findings provide a foundation for developing tools and approaches that align with designers' preferences, ultimately enriching the design process through meaningful integration of cognitive insights.
Composite offshore structures however pose challenges due to the involved complex damage mechanisms and the need for novel maintenance procedures, introducing uncertainties concerning their operation. A Structural Health Monitoring (SHM) system is proposed for increasing confidence in the safe operation of the new composite gangway.
The suggested SHM system relies on inverse Finite Element Methods (iFEM) deflection reconstruction using Fiber Optics (FO) strain data. The gangway design is simplified to a U-shaped beam geometry under bending load, modeled using IQS4 elements. Its performance was assessed using mock strain data generated numerically through FEM software.
Deflection reconstruction using both tri-axial and uni-axial strain measurements was investigated, revealing that uni-axial measurements can be sufficient for the current application. The sensing network was streamlined by focusing on line configurations along the length of the beam, leveraging the capabilities of FO sensors.
The introduction of strainless inverse elements highlighted the limitations of strain pre-extrapolation with Smoothed Element Analysis (SEA) for such a geometry. Modeling guidelines and their effect on improving the robustness of SEA are explored. A strain sensing network using four uni-axial sensing lines is found to offer a sufficiently accurate deflection reconstruction for the application.","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:d217b773-e8c7-4f42-8d10-64bbc4ed9a63","http://resolver.tudelft.nl/uuid:d217b773-e8c7-4f42-8d10-64bbc4ed9a63","Numerical Modelling of Skin-Stringer Separation in Thermoplastic Composite Stiffened Panels","Malladi, Avyadhish (TU Delft Aerospace Engineering)","Turteltaub, S.R. (mentor); Bisagni, C. (mentor); Alderliesten, R.C. (graduation committee); Giovanardi, Bianca (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis project focuses on the evaluation of the Extended Finite Element Model (XFEM) for modelling skin-stringer separation in thermoplastic composite stiffened panels. The study uses test results from a reference study in the literature on a PEKK-FC carbon composite panel with three stringers joined to the skin using a short-fibre reinforced butt joint. The modelling strategy was developed using Double Cantilever Beam (DCB) specimens. The XFEM-based panel models were then developed using two different damage initiation criteria: Quadratic Stress Criterion (QUADS) and Maximum Principal Stress Criterion (MAXPS). These models were compared with the Virtual Crack Closure Technique (VCCT) model from the reference study. The project also addresses the challenges posed by the crack tip impingement problem in the XFEM-based model with MAXPS and tests different strategies to overcome it. A proof of concept is provided for using the UDMGINI subroutine to address these challenges, setting the stage for future studies and algorithm development.","XFEM; VCCT; DCB; Stiffened Panel; butt-joint; Thermoplastic Composite; PEKK-FC; UDMGINI; skin-stringer separation; Post-buckling analysis; Abaqus","en","master thesis","","","","","","","","","","","","Aerospace Engineering | Structures and Materials","",""
"uuid:49068914-5ff6-4786-be8c-c39bea62722f","http://resolver.tudelft.nl/uuid:49068914-5ff6-4786-be8c-c39bea62722f","Exploiting the benefits of a mobility hub to incentivize shared car usage: To what extent could a mobility hub play a role in the adoption of shared cars located at the mobility hub?","Hoogenboom, Jim (TU Delft Civil Engineering & Geosciences)","van Oort, N. (graduation committee); van Wee, G.P. (graduation committee); Annema, J.A. (mentor); Bootsma, Anna (graduation committee); van Gerrevink, Iris (graduation committee); Delft University of Technology (degree granting institution)","2024","Recent research studies have been focused on the adoption of shared cars and mobility hubs separately. Which is why there exists a knowledge gap regarding the influence of a mobility hub on the adoption of shared cars. This qualitative research study aims to fill the knowledge gap by answering the main research question: To what extent could a mobility hub play a role in the adoption of shared cars located at the mobility hub? Multiple angles had to be researched as unilateral answering the main research question was not possible. Therefore, a literature study provides insight in which aspects that are related to the use of a shared car could be influenced by a mobility hub (sub question 1). Next, expert interviews contribute to the knowledge regarding the mutual influences between mobility hubs and shared cars (sub question 2). Finally, a case study captures what stimulates residents to use a shared car at their nearby mobility hub (sub question 3).
In the extensive literature study 50 relevant articles were collected. The Thematic Content Analysis (TCA) that followed identified reoccurring themes. This resulted in subthemes that are related to: financial aspects; functional requirements; personal requirements; aspects of the journey; the attitude of potential users; psychological influences; challenging characteristics of potential users and aspects of a mobility hub. By analysing their influence, it became apparent that the identified themes (i.e. the independent variables) have a causal relationship with shared car usage (i.e. the dependent variable) and that certain aspects of a mobility hub (i.e. the moderator variable) could influence this relationship. These relationships have been presented in a conceptual model. Based on the influence of the identified subthemes, suggestions have been made for the guidelines that a mobility hub should fulfil in order to influence these relationships. By fulfilling the guidelines, a mobility hub can be developed in such a way that it considers the tangible and intangible aspects potential users value to attract more potential users to the hub and lower the barrier of using a shared car located at the mobility hub. Therefore, this qualitative research study showed that there are indeed factors of a mobility hub that can influence the adoption of shared cars located at the hub.","shared car; Mobility hub; guidelines","en","master thesis","","","","","","","","","","","","Civil Engineering | Construction Management and Engineering","",""
"uuid:451373f3-51a1-41de-9318-4a6f83bb481d","http://resolver.tudelft.nl/uuid:451373f3-51a1-41de-9318-4a6f83bb481d","Plastic Waste as a Fuel for Transportation: A stated choice experiment on the personal preference and acceptability towards adoption to a plastic-based fuel","Six, Pascale (TU Delft Technology, Policy and Management)","Delft University of Technology (degree granting institution)","2024","Plastic is one of the major pollutants in the world and currently, more than 300 million tons of plastic are produced worldwide (Miandad et al. 2019). Since only 9.5% of plastic waste is being recycled, littering has caused a lot of non-recyclable plastics (NRP) that wander around damaging the environment and ending up in landfills, oceans and other natural environments (Benavides et al. 2017). This overload of plastic demands action to prevent a worsening situation. Therefore, alternative use of plastic waste is sought whereas a promising solution is to use plastic waste as a fuel for transportation. Plastic waste can be converted into various types of fuels, such as gasoline, diesel and jet fuels. To create these fuels, plastic waste undergoes a process called pyrolysis (Manickavelan et al. 2022). This research is done by first gathering information on the social influences on choice-making when consumers have to choose a fuel type. With this information, a survey is constructed existing of a stated choice experiment. With the results of the survey, further information is sought on the policy frameworks and infrastructures necessary for the implementation of a plastic-based fuel and the environmental impacts of using plastic as a fuel, as these aspects seem to impact the consumers most considering a fuel choice. Combining and analysing the information and degree of importance of each attribute can conclude whether the implementation of using plastic fuel will be feasible and socially acceptable. The outcome will be evaluated concerning the feasibility, performance limitations and social acceptance. The results showed the degree of importance for consumers of price, emissions and infrastructure, from most influential to least, regarding making a fuel choice researched with an unlabelled SCE (Stated Choice Experiment). However, when transmitting from gasoline to plastic, the labelled SCE showed the degree of importance for infrastructure, emissions and price from high influence to low influence. Since using plastic fuel is a transition of fuel, the main focus will lie on the results of the labelled SCE. Concerning missions, the most optimal solution to implement plastic fuel is by providing the fuel as a blend. From research, a blend existing of 75-80% fossil fuel and 20-25% plastic shows improvement in tailpipe emissions reducing CO2 emissions and smoke. For NOx emissions, discussion is still ongoing on whether more or less emissions are produced compared to fossil fuels. However, with the blend range of 75-80% fossil fuel and 20-25%, the least NOx are produced compared to other blend ratios. Since a blend is the most optimal implementation strategy, the ease of having access to plastic-based fuel will not differ from fossil fuels as it will be blended into the currently used fuels. Adding plastic oil to fossil fuels will therefore provide a solution to the excess of plastic waste worldwide with an additional advantage of producing less emissions during combustion compared to the currently used fossil fuels.","Plastic; Fuel; Social Acceptance; Stated Choice Experiment","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:39acca9a-53ba-4b9c-b9c0-b6c99f552e25","http://resolver.tudelft.nl/uuid:39acca9a-53ba-4b9c-b9c0-b6c99f552e25","The climate impact of hypersonic transport","Pletzer, Johannes (TU Delft Aircraft Noise and Climate Effects)","Grewe, V. (promotor); Dedoussi, I.C. (copromotor); Delft University of Technology (degree granting institution)","2024","At speeds roughly between five and ten thousand km/h, hypersonic aircraft offer the promise of an extremely fast means of transport. Growing concerns about climate warming, however, direct attention to sustainability. This thesis focuses on atmospheric composition and radiation changes by considering a range of individual hypersonic aircraft designs on trajectory and route network level.
State-of-the-art Earth system models are used for simulations, and results calculated with the EMAC model are subsequently compared with simulations performed elsewhere with the LMDZ-INCA model. The comparison to a third model, i.e. WACCM, with a very similar – but independent – model setup allows even further clarification. For model validation satellite measurements (ozone, water vapor) and aircraft measurements (ozone, water vapor, temperature) are taken into account.
After the introduction in the first chapter, the second chapter is a general description of the Earth system including anthropogenic perturbations, in particular perturbations from subsonic, supersonic and hypersonic aircraft emissions followed by a detailed explanation of methods and the EMAC model setup in the third chapter. A new research finding in the context of middle atmospheric chemistry is the increased methane and nitric acid oxidation following hypersonic emissions. This effect results in a (photo-)chemical net production of water vapor and eventually increases water vapor perturbations further, which is described in detail in chapter 4. In chapter 5 an analysis of atmospheric dynamics and transport of emitted trace gases in the middle atmosphere underlines the importance of the Brewer-Dobson circulation and shows the impact of polar stratospheric clouds on water vapor perturbations during polar winter. The evaluation of multiple hypersonic aircraft designed for different cruise altitudes shows that their climate impact increases with cruise altitude and can be approximately 10-20 times as much as a conventional aircraft (chapter 6). Emissions at different hypersonic cruise altitude and latitude regions show that the climate impact can vary more with latitude of emission than with altitude of emission (chapter 7). With rf_of_hypersonic_trajectories() a software was developed to estimate the climate impact of aircraft design and flight trajectory/network options in seconds based on robust results from Earth system modelling. Using the software it is shown that a cruise altitude optimization loop can reduce the overall climate impact of a state-of-the-art aircraft design (chapter 8).
There are two methodological highlights to mention in the context of the EMAC model. The first is a new MESSy submodel H2OEMIS, which was created as part of this thesis. H2OEMIS is an interface to include water vapor emissions in EMAC model simulations, which was not possible before. This submodel will generally be of interest for future evaluations of e.g. any vehicles emitting water vapor and the impact of volcanic eruptions with EMAC. The secondmethodological highlight is the application of a novel speed-up technique during simulation runs, which reduces the simulated years by twothirds. To conclude the summary, the four following points are important to take away. This thesis brought
• A new research finding on middle atmospheric chemistry: The identification of a chemical feedback that enhances the water vapor perturbation lifetime albeit an increasing chemical water vapor destruction
• A robust estimate of the climate impact of hypersonic aircraft for both specific aircraft designs and general atmospheric and radiative sensitivities showing a large altitude and latitude dependence
• An easily accessible tool for researchers and companies to estimate the climate impact of new hypersonic aircraft designs with low cost and low time
• An estimate how the development of hypersonic aircraft would contribute to a road map to a climate optimal aircraft industry compared to conventional aircraft
Therefore, this thesis will answer the main research question: 'To what extent can the structural performance of a timber-glass shear wall as a stability element in a timber module be used to accommodate for the stability of a mid-rise modular timber building?'
The approach to answering the main research question consists of several steps. First, a literature study was conducted on modular buildings and TGSW's. The outcome of the study has provided insight into how modular buildings are constructed in general and how relevant aspects such as progressive collapse, fire safety design, and foundation design influence structural design. The study also resulted in an analytical prediction model for the load-bearing capacity and stiffness of the TGSW. Through this prediction model, it became clear how the properties of individual components relate to the load-bearing capacity and stiffness of the total TGSW-system.
The second step was to propose a design for a modular timber building composed of timber modules. To save on computational time, the stability elements of the building are modelled using steel diagonals as an equivalent system for the TGSW. The cross-sectional area of the steel diagonals is directly related to the properties of the TGSW. Therefore, the steel diagonals have identical stability properties as the TGSW. In this study, varying the type of adhesive and the spacing of the screws was found to have the most significant impact on the overall structural properties of the TGSW. The horizontal connections are made of steel plates fastened with screws. The vertical connections are realised by shear plate connectors. The entire building was modelled in a 3D FEM programme to assess the structural behaviour of the building and its compliance with building regulations. Several building configurations ranging from 1:1 to 1:3 height-to-width ratio were investigated. For each building configuration, the cross-sectional area of the steel diagonals was adjusted within a specified range. This range corresponds to variations in adhesive type or screw spacing. As a result, design graphs were produced, which present the requirements for the load-bearing capacity and stiffness of the stability system. These can be compared to the load-bearing capacity and stiffness of the TGSW. This comparison can be used as a validation method to determine the viability of the TGSW stability element in a modular building.
The results of this study indicate that a modular building can be stabilised by a TGSW up to six stories within the height-to-width ratio of 1:1 to 1:3. The minimum building configurations per story height are: 3 modules high by 5 modules wide, 4 by 8 modules, 5 by 12 modules, and 6 by 18 modules. These slenderness ratios were governed by the strength of the TGSW. The limiting factor in the load-bearing capacity is the shear strength of the adhesive. These slenderness ratios could only be reached with elastic adhesives such as silicones.
The next step is to create a more extensive FEM model that could predict the load-bearing capacity and stiffness of the TGSW in a more accurate way compared to an analytical model. Furthermore, exploring the performance of the TGSW under different horizontal loads, such as earthquakes, would give valuable insight.","Modular Building; Stability system; Timber-glass shear wall; Timber modules","en","master thesis","","","","","","","","","","","","Civil Engineering | Building Engineering - Structural Design","",""
"uuid:995eb646-8425-47ab-877e-1686188611ad","http://resolver.tudelft.nl/uuid:995eb646-8425-47ab-877e-1686188611ad","The Object Catalog | enhancing UNDP's system and portfolio approach for development","van der Sluijs, Hannah (TU Delft Industrial Design Engineering)","Lloyd, P.A. (mentor); Celik, S (mentor); Uriartt, Simone (mentor); Delft University of Technology (degree granting institution)","2024","The challenges of today’s world don’t restrict to borders, specific industries or fields of expertise as linear development models may suggest. In order for development to react in a synchronized manner to capture the complexity of these crises, a transition has been initiated within the United Nations Development Programme (UNDP) and the way of doing development, called the portfolio approach. An approach that agrees with the statement Rittel en Webber (1973) that finding the solution to a problem is similar to understanding the nature of the issue. The goal of the new approach, developed by the Strategic Innovation Unit (SIU) of the UNDP is to move from linear project planning to a more systemic and holistic way of working within the discipline.
This report follows the online journey of an UNDP team into this new way of doing and discussing development. The journey did not go without hurdles, both external factors, political dynamics and organization hierarchy, and internal factors, adjusting to a new mindset and communication manner, influenced the learning process of the team.
Observations of these dynamics has led to an intervention in the domain of communication within the portfolio realm in order to socialize the principles of systemic approaches and bring the team closer to the challenge of concern by discussing its subjective stories. The powers of the universal and context dependent characteristics of physical objects is taken as a starting point. They functioned as a boundary object, a concept that facilitates collaboration between different groups and stakeholders adjusted to different social worlds (Star & Griesemer, 1989) and steers conversation to facilitate connection in the domain of complexity.
Experiments with a variety of UNDP members explored the possibilities of the objects. The unusual objects found during this research have proven to spark new information streams and offer specific insights on the subject matter. The project’s accumulated in an elaborate workshop designed to guide CO teams to explore tangible objects in their domain. The objects collected by the team in the workshop serve as valuable tools for the team’s internal collaborations and externalizing perspectives. Utilizing physical
objects to achieve this, aims to accelerate engagement, foster recognition and enable context-specific conversations, reinforcing the statements of both the necessity of a portfolio approach and its systemic nature.
The project aims to provide fresh perspectives on the transition to a portfolio approach and its communication strategies, contributing to the research on effective implementation and integration of the portfolio approach within UNDP teams. The report presents a practical and an alternative conversation starter on the systemic
aspects of the approach in order to facilitate engagement with the approach and emphasize a deeper (personal) involvement of the participants.","Systemic design; portfolio approach; objects; Workshop","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:d2d0a17a-0ec4-4ecd-a9cb-b98c8195d29b","http://resolver.tudelft.nl/uuid:d2d0a17a-0ec4-4ecd-a9cb-b98c8195d29b","Circular and sustainable playground equipment","Thomassen, Brent (TU Delft Industrial Design Engineering; TU Delft Delft University of Technology)","Sprecher, B. (mentor); Kuiper, J. (graduation committee); Delft University of Technology (degree granting institution)","2024","This project is focused on the development of circular and sustainable playground equipment (PE), as the Netherlands and its municipalities have set targets to become a Circular Economy in 2050. Furthermore, the PE should also encourage children to play outside more and engage in physical exercise. The reason for this being that children in the Netherlands do not play outside enough, which is often due to uninteresting playground designs.
The project started off with a theoretical framework, in which the 10R design strategies, such as reuse, repair and recycling, for the CE were examined on their effectiveness in playground design. Both academic literature and stakeholder & expert interviews enriched the knowledge needed to answer the research question. This resulted in the following design considerations which were the basis for developing the PE as described in this thesis:
Create an interchangeable and customizable system with components that are easy to (dis-)assemble (product-service system with modular play modules)
Design with a mono-material
Design with a material which comes from a waste stream
Design with a material which allows for form freedom
Design with a material which is resistant to wear and tear and external conditions (cold, heat, moist, UV radiation, etc.)
Eliminate redundant elements
Design PE modules which can fulfil multiple play functions
Design a connection system which allows for easy (dis-)assembly and consists of a minimal number of parts and different materials
Design for effective and minimal repairs and maintenance
Design with materials which can efficiently be recycled
I performed a study on an appropriate material and production method for the PE and from this I concluded on the use of 3D-printed Geopolymer with recycled aggregates, as it comes from a large Dutch waste stream, can be produced and efficiently recycled in the Netherlands, has a lifespan of several decades, allows for form freedom and colouring, and facilitates straightforward repairs and maintenance, making it an appropriate material for the Dutch CE. I was able to visit a 3D printing facility to get in contact with the material and production process, and even prototype my product here with 3D printing.
Based on conclusions derived from academic literature and a design session with 131 children aged 6-11, I concluded that the play functions climbing and swinging & swaying, among several others, could encourage children the most to play outside more and engage in more physical activity. These functions are translated into the following themes: Treetop Retreat, Rapid Rush, Acrobatic Adventure and Hideaway Hunt, which are the focus of the designed PE.","Playground; Circular economy (CE); Sustainability; Geopolymer concrete","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:68d3f999-c6f6-45ca-8209-d70a1fa00ef5","http://resolver.tudelft.nl/uuid:68d3f999-c6f6-45ca-8209-d70a1fa00ef5","Exploring Training Pair-Generation Strategies for Deep Metric Learning for Floor Plan Retrieval","Kuhn, Emanuel (TU Delft Electrical Engineering, Mathematics and Computer Science)","van Gemert, J.C. (mentor); Khademi, S. (mentor); van Engelenburg, C.C.J. (mentor); Oertel, Catharine (graduation committee); Delft University of Technology (degree granting institution)","2024","Existing content-based image retrieval models work well for natural photos, but not for images of architectural floor plans.
Previous work on floor plan retrieval has focused on graph-based methods, rather than image-based floor plans.
Training a CNN-based representation learning framework on segmented floor plan images with standard image augmentations does not result in semantically meaningful retrievals.
This work shows that a CNN-based representation learning model can learn features for retrieving floor plans that have similar graphs given the right training signal. Two methods were investigated here: GeomPerturb, a data augmentation that perturbs the underlying geometry of a floor plan, and a weakly supervised method with labels based on the graph edit distance between a pair of floor plans. The results show that while GeomPerturb learns representations that are correlated with the floor plan graph, training with GED labels leads to better retrievals both in terms of the floor plan graph and with respect to room shapes.
First, a novel watermarking scheme is proposed based on the early triggering of a well-designed STC policy, such that stability is guaranteed to be preserved. We show that this watermarking scheme, together with an event-triggered χ2 detector we design, is able to detect replay attacks. An online heuristic for obtaining an optimal early triggering policy is provided. If certain assumptions hold we show that the early triggering policy is a discrete uniform one. Through an illustrative example, both a quantitative and qualitative comparison between two other watermarking schemes are provided. We conclude that none of the watermarking schemes can claim absolute superiority, and trade-offs between all considered schemes exist.
Next, we propose a new type of attack called a switched zero dynamic attack (ZDA), and provide an algorithm on how to construct these switched ZDA. We show that certain STC systems are susceptible to such attacks, and demonstrate that by tuning the triggering parameters there exist sufficient conditions such that these attacks are no longer disruptive. The effect of additive perturbations and a non-zero initial condition, as well as the proposed tuning method, are shown in a numerical example. We provide a qualitative comparison between several other countermeasures in the literature, which we extend for aperiodic sampling when needed. Finally, shortcomings and future directions are discussed.","stc; watermarking","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:31117bb0-5f8b-496d-ac86-693b1524f733","http://resolver.tudelft.nl/uuid:31117bb0-5f8b-496d-ac86-693b1524f733","Reducing earthquake suffering: Solutions for vulnerable groups","Kljaić, Korina (TU Delft Industrial Design Engineering)","Bianchi, S. (mentor); Jansen, A.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","The thesis focuses on creating a solution aimed at reducing suffering in earthquake prone regions. The research done resulted in the development of Embrace, a wearable communication device designed to alleviate human suffering during seismic events in seismically active regions like Zagreb. Commencing with an exploration of challenges faced by people living in these quake affected regions, the research aimed to devise a cost-effective, visually appealing solution to these issues.
Methodologies encompassed literature reviews, interviews, cause-effect analysis, and Inside out Design approach, offering crucial insights into user needs and preferences. Following an evaluation of various design concepts, Embrace emerged as the preferred solution, aligning with project requirements.
Embrace integrates LoRa technology for long-range communication, empowering individuals to request aid during earthquakes. Its design process involved modeling with Fusion 360, 3D printing, and utilizing liquid rubber for silicone shells. Sizing considerations, ergonomic enhancements with fillets, and a hierarchy of requirements guided its development.
Future research pathways should include testing Embrace's functionality, exploring diverse shapes and materials, and investigating additional features like smartwatch integration. The thesis resulted in development of Embrace as a significant contribution to wearable technology, enhancing safety and well-being during seismic events.","Earthquake; Wearable Technology; smart bracelet; LoRa Network; satellite communication; reducing suffering","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:73b41751-f9ab-43fc-b1c9-b65722109eaa","http://resolver.tudelft.nl/uuid:73b41751-f9ab-43fc-b1c9-b65722109eaa","Orbit Estimation of Small Jovian Satellites","Dahmani, Fabien (TU Delft Aerospace Engineering)","Dirkx, D. (mentor); Delft University of Technology (degree granting institution)","2024","The primary motivation for this work was the lack of open-source or clearly motivated studies describing the orbit estimation of natural satellites. The capability to accurately model the trajectory of the moons of Jupiter is crucial for properly understanding the evolution of the Jovian system and, by extension, the solar system. Considering the small Jovian moons remain relatively unknown, they will be the focus of this study. The goal of this project was to develop a framework for the full estimation process, based on the Tudat software library, starting from raw astrometric observations, to be made available publicly. The first step was designing a new data processing algorithm, capable of uniformising the observational data. These measurements are reported in a wide variety of formats, with differences in time format, time scale, orientation, and observation type, amongst others. The developed software was able to produce Tudat-compatible observations with limited user interaction. These processed measurements were then analyzed and validated, first by examining the mean residuals with respect to existing ephemerides to detect remaining biases in the data, before comparing the standard deviation of these residuals to those reported in their original publication, whenever available. Secondly, the estimation framework was set up. Based on the processed astrometric observations, the orbits of three minor Jovian satellites, Himalia, Elara, and Amalthea were estimated as case studies. Each of these posed its own set of challenges, but together they yield a good representation of the full range of outer moons. The SPICE kernel ephemerides were used to evaluate the quality of these orbital solutions. Estimating Himalia’s orbit proved the easiest, as it is the minor moon that is observed the most, in combination with its relatively slow dynamics. One problem was the fact that there was a remaining unmodeled bias in the oldest, i.e. pre-1960, observations due to errors in converting from old to new frames. Removing these observations and replacing them with simulated measurements with realistic residuals both proved to reduce the difference with respect to the SPICE benchmark to within the uncertainty level of this very benchmark. This proves that the framework allows to accurately estimate the ephemerides of Himalia, although no conclusions could be drawn on the exact contribution of the old observations. Elara’s orbit is in many ways similar to that of Himalia, as they are part of the same orbital group. However, a close approach with this more massive Himalia in 1949 had a significant impact on Elara’s trajectory. Therefore, estimating Elara’s orbit is not limited to its initial state. Instead, Himalia’s gravitational parameter is determined concurrently to optimize the solution. However, even when determining this gravitational parameter, it became apparent that the current dynamical model could not perfectly capture the dynamics at the close approach, due to the limited amount of data before the event, leading to an error of several hundred km. This is still well below the residual of the observations, however. Finally, Amalthea proved to be the most difficult body to get an accurate orbital solution for. Since Amalthea is an inner moon, as opposed to the outer moons Himalia and Elara, its angular velocity is over 500 times higher. This logically makes both timing and position errors significantly more impactful. Additionally, the very limited amount of data, which is constrained to just a few campaigns of several nights, further hamper accurate orbit determination. By limiting the step size of the update in the estimated initial state between iterations to a standard deviation of 100 km by defining the a-priori covariance, a stable solution, accurate to several 100 km could be found. A preliminary investigation of the contribution of simulated spacecraft data indicated that the few available spacecraft observations of Amalthea have a large impact, which warrants further studies. Thus, through determining and analyzing the orbit of these three case studies, the quality of the developed framework is ascertained. The solutions proved to lie within the uncertainty region of the ephemerides published in SPICE. Inaccuracies in the estimated orbit could always be linked to deficiencies in the input data, thus not taking away from the quality of the framework.","","en","master thesis","","","","","","","","2026-02-06","","","","Aerospace Engineering","",""
"uuid:83e82e29-78c4-4098-96b9-49d52932df6b","http://resolver.tudelft.nl/uuid:83e82e29-78c4-4098-96b9-49d52932df6b","Temporal dynamics of resilience in the palladium supply chain: A data analytics approach","van Bree, Arnoud (TU Delft Technology, Policy and Management)","van Beers, Cees (mentor); Comes, M. (mentor); Delft University of Technology (degree granting institution)","2024","Palladium is a critical raw material that is considered economically and strategically important by various national governments. The palladium supply chain is subject to several supply chain risks, including the geopolitical risk of potential Russian palladium export restrictions. Considering these disruption risks, it is essential to gain insight into the resilience of the palladium supply chain. Accordingly, this study investigates the temporal dynamics of resilience in the palladium supply chain using literature review, data analysis, and regression modelling. To that end, the diversity of supply, stockpiling, price, and substitution mechanisms from the qualitative resilience framework by Sprecher et al. (2015) are operationalised in terms of quantitative proxy variables. A PCA-weighted compound resilience index is constructed and quantitatively validated using the palladium market balance as a resilience performance indicator. It is found that the palladium supply chain exhibited an overall improvement of resilience, but still a structural lack of resilience during the years 2012-2021. This thesis contributes to the scientific study of how material criticality and resilience change over time. Moreover, this study informs policy-makers about potential risks for the palladium supply chain and makes policy recommendations to improve the resilience of the palladium supply chain.","Critial Raw Materials; Palladium; Supply chain resilience; Platinum group metals; Metals criticality","en","master thesis","","","","","","https://drive.google.com/drive/folders/1wCprTfJGjo6QvgZBjBKBoIyDDmMUJCPG?usp=sharing Link to data files","","","","","","Engineering and Policy Analysis","",""
"uuid:198943dd-99d3-4bea-92f2-168aa1849a5a","http://resolver.tudelft.nl/uuid:198943dd-99d3-4bea-92f2-168aa1849a5a","A day and night train interior design for improved passenger comfort and improved train usage","Out, Annabelle (TU Delft Industrial Design Engineering)","Vink, P. (graduation committee); Vledder, G. (mentor); Donners, Barth (graduation committee); Delft University of Technology (degree granting institution)","2024","This project explores the prospects for interior design in a dual purpose train that can run both day and night for improved utilization and comfort.
Contemporary trains are categorized as either exclusively for daytime or nighttime use. Their interiors limit them to specific temporal contexts. For instance, in daytime trains, passengers are confined to sitting positions and cannot lie flat, resulting in suboptimal sleeping comfort. Thereby the appeal of such trains for night (long distance) travel is reduced. Conversely, in existing night trains, while passengers can lie flat, the fixed layout featuring compartments and beds makes the capacity of the train too low for daytime use. Moreover, night trains face strong competition from aviation, rendering their utilization challenging.
A solution to this problem involves designing a train interior that serves the dual purpose of accommodating both daytime and nighttime travel. Drawing insights from research, and the existing coach geometry, four distinct design directions were developed. Emphasis was placed on striking a balance between coach capacity and passenger comfort, recognizing the inherent tension between these two factors in this context. One of these directions was further refined into the final concept. In refining the final concept, the emphasis was on creating a passenger experience characterised by privacy, safety and comfort. Two Virtual Reality tests were conducted among other efforts to achieve this goal.
The final concept features a symmetrical coach with a centrally positioned entrance. The entrance aligns with the platform's height, facilitating easy boarding for passengers
with reduced mobility. The central hall houses a self-service bar for acquiring food and beverages. Adjacent to the central hall are seats on both sides. During the day, passengers can occupy these seats, which are configured in sets of two facing each other. No ticket reservation is necessary for daytime travel, and the coach accommodates 72 passengers during this period. Capacity is thereby 10% lower than in daytime-only trains. At night, the seats transform into beds, offering passengers the option to lie flat.
Privacy screens can be easily placed around the bed, and overhead lockers are available for secure luggage storage. The nighttime capacity is 36 passengers, which is the same capacity as the sleeper accommodation in night trains. Ticket reservation is obligatory for overnight travel. The coach incorporates two toilets and two washrooms. Distinct zones within the coach, such as a quiet zone, a socializing zone, and a women only zone for nighttime travel, contribute to a tailored and comfortable passenger experience.","Privacy; Security; Capacity; Night train","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:e2df20c7-789a-49b9-b3c4-e746f607875a","http://resolver.tudelft.nl/uuid:e2df20c7-789a-49b9-b3c4-e746f607875a","NRG-beamFoam: a simplified numerical FSI solver developed in OpenFOAM for modelling axial-flow in nuclear reactors","Popi, George (TU Delft Aerospace Engineering)","van Zuijlen, A.H. (mentor); Zwijsen, Kevin (graduation committee); Delft University of Technology (degree granting institution)","2024","Nuclear power is increasingly seen as a potential solution to the decarbonization of the energy sector in the coming decades. However, one of the main causes of downtime for current-generation nuclear reactors is the phenomenon of Grid-To-Rod-Fretting (GTRF) inside the reactor core. This is predominantly caused by Fluid-Structure Interaction (FSI), where the turbulent cooling water flow causes unwanted vibrational behaviour of the long and slender rods where the fission reaction takes place.
To quantify the effects of GTRF, before this thesis, a numerical FSI workflow called NRG-FSIFOAM was developed by Nuclear Research Group (NRG). The fluid modelling consisted of a synthetic turbulence model (AniPFM) developed in OpenFOAM. The structural solution was obtained using a 3D Finite Element Method (FEM) solver implemented in deal.II, while the mapping and coupling between the two solvers was handled by preCICE.
In this context, the objective of the thesis is to propose a simplified and cost-effective structural solver, without compromising the accuracy of the methodology. To this end, an eigenmode-based Reduced-Order Model (ROM) of a 1D beam-element FEM formulation is proposed. To further improve the computational costs, by taking into account the 1D FEM formulation of the structural solver, novel mapping routines between the fluid and the structural grid are also proposed. To ensure a strong coupling between the two domains, an Aitken subiteration algorithm is used. What’s more, to simplify the architecture of the methodology, the new features are directly implemented in OpenFOAM. Thus, the newly proposed workflow is fully contained within OpenFOAM, eliminating the need to additionally use deal.II and preCICE. This newly proposed FSI methodology is called NRG-beamFoam.
The thesis first deals with the individual verification of the structural solver, the mapping routines, and the Aitken subiteration scheme. Subsequently, all of the elements are combined within FSI simulations for the same benchmark case that was used for the validation of NRG-FSIFOAM. It is found that for simulations where an Unsteady Reynolds-Averaged Navier Stokes (URANS) fluid model is used, NRG-beamFoam reduces the computational cost per FSI subiteration by 48% compared to its NRG-FSIFOAM predecessor, while obtaining a 0.5% relative difference in the frequency and the damping ratio characterizing the structural dynamic response. What’s more, using the ROM, the instantaneous deformations of a single rod to turbulent excitation by axial water flow appear to be accurately computed using a total number of degrees of freedom that is reduced by a factor of approximately 103 compared to the FEM solver of NRG-FSIFOAM. Further research is recommended to improve the stability of NRG-beamFoam when coupled with the AniPFM for simulation times in the order of seconds. Furthermore, future studies ought to explore the causes for the small amplitude differences observed between the outputs of the ROM and the FEM solver for FSI simulations.
Alkaline water electrolysis has emerged as one of the most promising electrolysis methods due to its large-scale operation, long durability and low costs. This does not come without challenges, one of them being leakage currents, which reduces the efficiency of the electrolyser. Leakage currents occur when not all current is used for hydrogen production, but some of it leaks into, for example, the produced hydrogen stream. To reduce these leakage currents, more research into the origins is needed. The first step is modelling the electrolysis while considering as much as possible of the physics happening inside the system. Current models of alkaline water electrolysers are either modelled using only mathematical equations or neglect the operating parameters, which makes the results highly variable per system. Other models do use analytical methods with experimental results, but these models only comprise one electrolysis cell rather than a full stack.
This work consists of developing two three-dimensional models, validating them using experiments, and using them to predict the effect of changes in geometry. The first model was made using COMSOL Multiphysics software and used to research the water electrolysis stack, which comprised one or eight cells using electrochemical relations and physical data. It was found that a model could be made that fitted the experiments within the error margin of the experiments (<2.5%). It lacked flexibility but overall showed good results for an electrolyser stack of one or eight cells. The second model was made using an equivalent electrical circuit (EEC) of the electrolyser in Python via the PySpice module. A steady-state model, including the leakage currents, could be developed by calculating all system resistances, namely the cell, inlet/outlet, and manifold resistances. This model overestimated the performance of the electrolyser by 10-15% for low current densities and 2-4% for high current densities. Nevertheless, it was highly adaptable for different scenarios, making it valuable for research into optimising the electrolysis stack. Both models were used to predict the effect of changes in geometry; the effect of the length of the inlets, and the number of cells. This showed that the EEC model was better suited for this research.
This is not only an issue for cities that attempt to transform there mobility landscape to a more bicycle-friendly one, but also for established cycling cities that face new challenges because of the introduction of new vehicle types (e.g., e-bike, e-step) and new mobility business models (e.g., shared mobility, flash delivery). The academic world is also affected by the fact that cyclist simulation is understudied. The literature review of this thesis reveals that the academic landscape on this subject is foggy and unclear. The most popular model in academia is the Social Force Model (SFM). However, just the SFM leads to unsatisfactory behaviour, as is confirmed in the case study of this thesis. Thus, the academics propose a hybrid model. Herein, the SFM is constrained by additional rules, regimes or decision making processes. However, these propositions are tailored to cycling in a specific context and they are created in unmentioned software, using unmentioned programming languages. This hampers the possibility to replicate and verify their study.
The primary conclusion is that academics and simulation software developers should work towards a standardised behavioural model for cyclists, similar to the SFM for pedestrians and the car-following model for motorised traffic. An example of a leading principle for cycling behaviour could be a model where cyclists move along predetermined trajectories rather than being led by a force. This seems to solve the challenges researchers face regarding the operational behaviour of the cyclists.
It is also advised in future research to discuss the semantics of cyclist behaviour simulation. Literature that used this principle of predetermined trajectories still referred to their model as a model based on the SFM. This understates the fundamental criticism of these researchers on the SFM.
Lastly, commercial software companies are advised to actively partake in this process of creating a standardised model for cyclist simulation. With pro-cycling policy becoming more popular in cities all over the world, it is expected that municipalities and research institutes will show interest in a standardised model for cyclist behaviour when offered by a simulation software company. Moreover, such a standardised model incorporated in an applied simulation software should improve the verifiability and replicability of academic research. As a properly calibrated model for cyclist behaviour, would mean that less academics are inclined to create their own custom model for their research.
If these proposed developments come to fruition, other research subjects and applications become possible or more accessible. It should allow peer reviewers to test a researcher’s simulation model more easily. It enables urban planners and traffic engineers of local governments to quantitatively test their infrastructure designs and it enables academics to study the rapidly changing urban mobility landscape. For instance, it provides a possibility to experiment with infrastructure designs, aiming to tackle the contemporary challenges of established cycling cities.
Purpose: The goal is to develop a ML algorithm that can effectively predict neurological outcomes after spinal surgery using IONM data that include both motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs), and analyze its key predicting features. To more effectively determine the specific independent contribution of both separate modalities, a separate ML model will be created for both MEP and SSEP in addition to a combined MEP-SSEP model.
Study setting: Retrospective study.
Patient sample: A total of 67 patients were analyzed.
Outcome measures: The neurological status three months postoperatively compared to the preoperative status, categorized into three classes: 'Neurological stable deficits', ‘Neurologically intact’ and 'Neurological improvement'.
Methods: 260 features were obtained from patients who underwent spinal surgery monitored by IONM. During nested cross-validation, the data was split into five folds, for both the inner and the outer loop. The four ML classifiers developed were support vector machine, K-nearest neighbors, random forest and extreme gradient boosting, and tested along the three modalities MEP, SSEP, and MEP-SSEP combination.
Results: Extreme gradient boosting outperformed the other classifiers on all performance metrics. The combined MEP-SSEP model exhibited the highest scores for sensitivity: 70.4%, specificity: 88.3% and accuracy: 87.1%, while the MEP model exhibited the highest performance for precision: 75.6%. Highest predicting scores per individual class were also obtained by this XGBoost classifier on the combined MEP-SSEP model. Key predicting features were the presence or absence of preoperative neurological deficits and last measured signal latency compared to baseline, with a contribution of 29% and 13.5% in the best performing model, respectively.
Conclusion: A reliable prediction of neurological outcomes three months postoperatively can be made combining MEP and SSEP IONM features, provided that the patient's preoperative status is accurately documented and included in the prediction. Though either MEP or SSEP features alone offer predictive value, MEP features show superior predictive values compared to SSEP features when both modalities are accessible, with latency emerging as a prominent predictive IONM feature.
The principle of a catenary relies on the equilibrium between a vertical point load and the vertical component of the tie force in the deflected floor elements. Larger deflections result in a lower required tension resistance but demand a larger deformation capacity in the components. This study introduces a catenary equation to determine the required tensile resistance in a catenary at a specified elongation, creating a catenary requirement boundary. For a timber modular building to form robust catenary action, the axial force-elongation response in a catenary must meet this boundary. The catenary equation and the force-elongation response of the catenary form the basis of the connection optimisation, as the inter-module connection governs the response.
To determine the optimised mechanical properties of an inter-module connection in a timber modular building, a case study was performed on a building consisting of twelve post-and-beam modules in width and five modules in height. To determine the effect of a change in the inter-module connection design on the force-elongation response of the buildings, quasi-static numerical analyses were conducted on 2D models, focussing on the frontal view frame of the building, and the floor plane. The load distribution through the floor system and corresponding deformation were added to the frame model by use of spring boundary constraints, after which the catenary could be examined.
As a catenary can be formed by increasing the axial resistance, or its ductility, two optimisation methods were formulated, resulting in a high-strength inter-module connection and a ductile inter-module connection with a fuse. The optimisation process is based on iterations of the inter-module connection design. The resulting high-strength connection required a 143% increase in tension resistance, while the ductile connection relied on a 55% increase in resistance and a 550 mm fuse.
This study underscores the complexity and critical importance of correct connection design to ensure structural robustness, emphasising the need for sufficient strength and deformation capacity. While the proposed methodology serves as a valuable tool for optimising connections in timber modular buildings, further research is recommended by including dynamic analyses in the optimisation process and experimental testing of inter-module connections to enhance the accuracy of the models.","Robustness; Catenary action; Modular construction; Connection design; Timber; Finite Element Analysis","en","master thesis","","","","","","","","","","","","Civil Engineering | Structural Engineering","",""
"uuid:064301aa-1905-45b8-8213-a9629dda3cb4","http://resolver.tudelft.nl/uuid:064301aa-1905-45b8-8213-a9629dda3cb4","Numerical analysis of multiaxial test setup for composite cryogenic hydrogen tank development","Lentner, Mateusz (TU Delft Aerospace Engineering)","Atli-Veltin, B. (graduation committee); Dransfeld, C.A. (graduation committee); Koord, Josef (mentor); Delft University of Technology (degree granting institution)","2024","Hydrogen is one of aviation's most promising fuel alternatives in the coming years. However, to store it, a large and light vessel is needed.
The solution to this problem can be the carbon fibre fuel tank. Composite structures provide significant weight savings, which is crucial in this application. However, despite its superior performance, the hydrogen molecules permeate through the CFRP tank wall. Hence, researchers must first understand the driving phenomena to design a safe and robust hydrogen tank. The only proven way to do this is through experiments, but they must also be carefully considered to deliver representative results.
In this research, the question of how to perform the permeation and leakage testing of the CFRP laminates to accurately represent the behaviour of a full-scale hydrogen tank is being answered. The numerical analysis method has been used to evaluate different testing parameters and aid the development of the new testing rig. This thesis is the collaboration between the TU Delft and the DLR.","composites; CFRP; hydrogen; Permeability; Leakage; tank storage; Testing; FEM analysis; Cryogenic; Cryogenic Tanks; Hydrogen Tank","en","master thesis","","","","","","","","","","","","Aerospace Engineering | Structures and Materials","",""
"uuid:b1e3504c-53c3-4faf-837c-c9346dbddc97","http://resolver.tudelft.nl/uuid:b1e3504c-53c3-4faf-837c-c9346dbddc97","Model validation for bird strike crashworthiness","Post, Melvin (TU Delft Aerospace Engineering)","Castro, Saullo G.P. (mentor); van de Waerdt, Wydo (mentor); Teuwen, Julie J.E. (graduation committee); Wang, Xuerui (graduation committee); Delft University of Technology (degree granting institution)","2024","Bird strike simulations require accurate information about the nonlinear material properties of the bird and structure, dynamic changes in contact between bird and structure, and large displacements and rotations of the structural elements. The soft-body nature of birds allows it to flow fluidly upon impact, making accurate simulation validation difficult. Setting up a model requires evaluating and considering a large number of parameters. To simplify the process of obtaining validated bird strike models, a set of guidelines for setting up the simulations, covering the major parameters that influence the validation of the models, is established. This was done for an EWVT-SPH (Element Weighted Voronoi Tessellation Smoothed Particle Hydrodynamics) bird model by following the building block approach laid out by the aerospace standards of SAE-G28 for both rigid and complaint target structures.","Crashworthiness; Bird strike; Abaqus Explicit; Validation; SPH; SAE-G28; Building Block Approach","en","master thesis","","","","","","","","2026-02-16","","","","Aerospace Engineering","",""
"uuid:cf110916-b6dd-4a46-a9d7-19a6197291da","http://resolver.tudelft.nl/uuid:cf110916-b6dd-4a46-a9d7-19a6197291da","A System of Systems Aircraft Design Framework: Demonstration Using a Seaplane Transport Network in the Greek Islands","Nugnes, Vincenzo (TU Delft Aerospace Engineering)","Varriale, Carmine (mentor); Prakahsa, Prajwal (graduation committee); Delft University of Technology (degree granting institution)","2024","This paper presents a System of Systems Engineering approach to aircraft design. For this purpose, conventional design disciplines are coupled with Agent-Based Modeling and Simulation (ABMS) defining a unique optimization problem. The proposed methodology is applied to design seaplanes for an on-demand transportation system connecting the Greek islands. Within this network, diverse scenarios are analyzed by varying parameters of the model such as fleet size and travel demands at each seaport. The objective is to show the impact of including ABMS in the design workflow on the optimized seaplane design parameters. The optimum designs are evaluated on the basis of a number of classic performance metrics, to assess to what extent they can represent a competitive alternative to existent maritime means of transportation. The results reveal optimal fleet performance for seaplanes characterized by lower cruise speeds and passenger capacities, as compared to those derived from conventional methodologies and to existing designs.","system of systems; conceptual aircraft design; agent-based modeling and simulation; seaplane","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:b74db5c1-2407-4755-98ad-517abb0eabbe","http://resolver.tudelft.nl/uuid:b74db5c1-2407-4755-98ad-517abb0eabbe","Ringdown of high-Q nonlinear Si3N4 beam resonator with multi-overtone recording","Schoone, Bart (TU Delft Mechanical, Maritime and Materials Engineering)","Alijani, F. (mentor); Norte, R.A. (graduation committee); Keşkekler, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Micro- and nanoelectromechanical (MEM/NEM) resonators are used in numerous fields of engineering and are crucial for time keeping, synchronization, and sensing applications. These systems are subjected to energy dissipation, which is a limiting factor in the performance. Extensive understanding is essential when nonlinearities show up in both stiffness and dissipation, to design appropriately. Focusing on dissipative mechanisms, this paper explores the vibrational behavior of a suspended clamped-clamped beam fabricated from silicon-nitride in the nonlinear regime. This study reveals a notorious decay in ringdown, when the resonator is decoupled from its vibrational power. A sustained amplitude is observed for up to 8 seconds. Though the exact source of this anomaly remains elusive, it is suggested that it might include modal coupling and/or optomechanical effects","nanomechanical; Nonlinear Dynamics; Mode Coupling; Nonlinear damping","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:998d2af4-8eae-4bfa-9146-5d4fae33b6e2","http://resolver.tudelft.nl/uuid:998d2af4-8eae-4bfa-9146-5d4fae33b6e2","From Pain to Brain: Exploring Functional Connectivity in Chronic Pain Patients with Magnetoencephalography","de Moel, Lisanne (TU Delft Mechanical, Maritime and Materials Engineering)","de Vos, C.C. (mentor); van de Ruit, M.L. (mentor); Frankema, S.P.G. (mentor); Reinders, L.J. (mentor); Delft University of Technology (degree granting institution); Universiteit Leiden (degree granting institution); Erasmus Universiteit Rotterdam (degree granting institution)","2024","Introduction:
Chronic Pain (CP) presents a complex and prevalent issue that significantly affects individuals and society. Exploring the complexities of CP involves analyzing Functional Connectivity (FC), a process that identifies how different brain regions communicate across distances. Magnetoencephalography (MEG) is particularly effective for FC analysis, offering advantages over Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) due to its superior temporal resolution. Most studies on FC in CP have focused on resting-state analyses, leaving a gap in research on connectivity responses to noxious stimuli in CP.
Study aim:
The overarching goal of my exploring study is to investigate FC differences in response to noxious stimuli between individuals with CP and Healthy Controls (HCs) across different frequency bands, using MEG. This encompasses the comparison of FC patterns within pain-related brain regions between these two groups, the analysis of their response to a noxious stimulus, and the synthesis of these findings to identify potential differences in how the two groups respond to noxious stimuli.
Methods:
The study involved 17 individuals with CP and 17 HCs, each undergoing MEG sessions within a conditioned pain modulation (CPM) paradigm. During each CPM block, 22 noxious stimuli were applied to the right tibial nerve. FC was computed between pain-processing regions using phase and amplitude-based metrics in different frequency bands. Connectivity patterns were compared between the groups using a non-parametric permutation test. Connectivity was also evaluated on a time-scale to observe potential changes in the FC in response to the stimulus. These results were taken together to observe potential differences in the groups in response to the stimulus.
Results:
In comparing FC patterns across the entire epoch between the HC and CP groups, there is a predominant observation of increased FC in the CP group relative to the HC group. The insula and Dorsolateral Prefrontal Cortex (DLPFC) emerged as central hubs, and these alterations were most prominent in the beta (13-29 Hz) and gamma-low bands (30-45 Hz). An increase in FC in the mean response over all scout pairs and both groups was observed immediately following the stimulus, particularly in the theta band (5-7 Hz). Additionally, in investigating the specific hypothesis that there may be distinct FC responses to noxious stimuli between the HC and CP group, the findings indicate subtle differences rather than clear, pronounced patterns, with findings in the theta, alpha and gamma-low bands.
Conclusion:
My study explored FC differences in response to noxious stimuli between individuals with CP and HCs across different frequency bands, using MEG. Higher FC was predominantly observed in the CP group, suggesting more interconnected pain-processing networks. Key regions demonstrating this increased FC included the insula and the DLPFC, suggesting an altered insula-DLPFC network potentially influenced by underlying physiological factors of the CP group. Specifically examining differences in FC response to the noxious stimulus between the HC and the CP group yielded in subtle differences rather than clear, distinct patterns. This study stands out as the first using MEG to identify FC in CP in response to noxious stimuli. Future research should focus on refining connectivity as a biomarker for treatment follow-up and potential outcome predictor.","Brain connectivity; Chronic Pain; magnetoencephalography","en","master thesis","","","","","","","","","","","","Technical Medicine","",""
"uuid:078d7a2a-8202-4b12-b510-19077bd50863","http://resolver.tudelft.nl/uuid:078d7a2a-8202-4b12-b510-19077bd50863","Comfort in a Vehicle Seat: Research and Redesign of a Head Support for Sleeping Purposes","Sabater Campomanes, Rebeca (TU Delft Industrial Design Engineering; TU Delft Sustainable Design Engineering)","Vledder, G. (mentor); Vink, P. (graduation committee); Franz, Matthias (graduation committee); Delft University of Technology (degree granting institution)","2024","With the evolution of Autonomous Vehicles for the near future, BMW has designed a new seat for their vehicles, whose aim is to offer the greatest amount of comfort possible. Their main challenge now is to transform this level of comfort even when passengers want to sleep on the road, or while charging their vehicles. When it comes to confined spaces such as seats, obtaining a comfortable sleep has always been a challenge.
Taking into account the difficulty in achieving comfortable sleep in a seat, one of the main goals of BMW is to further enhance this seat within the context of sleeping. Sleeping is becoming one of the most popular activities among those passengers during a journey, and it is expected to grow with the integration of fully autonomous vehicles. Therefore, the first goal of the project is to analyze the seat to ensure maximum comfort when sleeping, and the second goal is to tackle the main area of discomfort with a design proposal.
For this, a thirty-minute sleeping research is conducted with sixteen participants, evaluating two different backrest angles (120º and 140º). The results show a preference of reclined backrest of 140 degrees, and an increase in comfort compared to sleeping in conventional seats. All participants had a good nap with this reclination, with an average amount of sleep of fourteen minutes. Regarding the seat analysis, the most uncomfortable part of the seat is the headrest, due to the lack of support for neck and head, and the lack of height adaptability to different demographics. The second area of discomfort is the leg support and the lack of footrest.
With these results in mind, the second goal is to develop an attachable head support that can be integrated in the BMW seat, for offering more comfort while sleeping in a reclined position. The main requirement considered is to make it adjustable in the area of head, neck, and height of the user.
The proposed design consists of two main components: a head support and a neck support. An integrated mechanism in the foam allows the adjustment of both to the width of the head and neck. In addition, a mechanism allows adjusting the height of the support to the desired position. Different prototypes are developed to assess the viability of the design features and feasibility for its integration in the seat.
A subsequent user test involving ten participants is conducted to validate the comfort and functionality of the design. The participants were asked to sleep in the seat making use of the new support. In order to obtain more objective results, four pressure sensors are integrated in the product to calculate the ideal pressure distribution exerted by the users. The data obtained from the sensors corroborated findings from literature research. Additionally, the support significantly increases the comfort after a thirty-minute nap in comparison to sleeping without support.
An analysis of the daily maximum traffic data of the transport core is performed, to determine the most suitable models for the prediction of network traffic. The data analysis, employing time series decomposition, revealed non-stationary trends and annual seasonality; traffic decreases throughout the summer and increases in the winter. An upward trend in the frequency and intensity of traffic peaks, highlights the growing demand and shifts in usage behavior. The extreme traffic peaks in the historical data were correlated to F1 race days and other anticipated events.
Two algorithms that integrate exogenous variables were assessed to predict the extreme values. The models either yielded inaccurate traffic predictions or encountered challenges in interpretability and pattern recognition, with the limited amount of data available. In response to these limitations, a decomposed forecast was created that predicts the trend and seasonality. Furthermore, Extreme Value Analysis (EVA) was implemented to address the extreme values in the data.
The final prediction framework combines the decomposed forecast with EVA for the next six quarters and outperforms the other models. The model effectively captures extreme values and provides insights into the maximum expected peaks and risk levels. The substantiated forecasts of the EVA model and the manual predictions yielded comparable results. However, the EVA model provides better insights into the likelihood of exceeding specific traffic values, which enhances capacity calculations and precision.
The prediction framework has been integrated into the business interface of KPN, which marks the initial step in the automatization of short-term capacity planning. The research insights emphasize the intricate nature of accurate prediction of future demand and advocate for scalable solutions beyond building new capacity. These solutions range from short-term mitigation to long-term strategies designed to alleviate high network loads. They underscore the importance of the implementation and integration of
dynamic decision-making within a digital twin of the network to ensure sustained effectiveness.","Extreme Value Analysis; capacity planning; network traffic; Time series analysis; Time series prediction","en","master thesis","","","","","","","","","","","","Electrical Engineering | Wireless Communication and Sensing","",""
"uuid:b2bdbbe2-2dda-4fce-8266-ae73bd12de91","http://resolver.tudelft.nl/uuid:b2bdbbe2-2dda-4fce-8266-ae73bd12de91","A Step Towards Understanding Normalizing Flows and their Likelihood Behavior","de Bruin, Niels (TU Delft Electrical Engineering, Mathematics and Computer Science)","Loog, Marco (mentor); van Gemert, J.C. (mentor); Delft University of Technology (degree granting institution)","2024","Normalizing flows have demonstrated their ability to learn complex and high-dimensional distributions. However, the behavior of normalizing flow likelihoods are not yet fully understood, particularly when exposed to outlier data, where it has been observed that large likelihoods are often assigned to inputs that are substantially different from the training set. To better understand the likelihood behavior and outlier detection capabilities of normalizing flows, we analyze a more restricted version of the model using synthetic test data from parametric distributions, allowing access to the density of the underlying distribution.","Normalizing flows; Generative AI; Outlier Detection","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:55a416e1-4310-44e8-be98-3ccb7f82e5a0","http://resolver.tudelft.nl/uuid:55a416e1-4310-44e8-be98-3ccb7f82e5a0","Quantum Acoustics with high-overtone bulk resonators and superconducting qubits: High-Q planar devices, phononlasers, and quantum ghosts","Franse, W.J.M. (TU Delft QN/Steele Lab)","Steele, G.A. (promotor); Groeblacher, S. (copromotor); Delft University of Technology (degree granting institution)","2024","The field of quantum acoustics studies high frequency sounds generated at low temperatures such that quantum mechanical effects become relevant. The studies mainly revolves around propagating quantized sound waves, or phonons, a collective excitation of atoms in solids or liquids. In quantum acoustics, the engineering and design tools described by circuit quantum
acoustodynamics (cQAD) are used to develop quantum acoustic devices that are coupled to superconducting qubits. cQAD enabled the demonstrations of quantum ground state cooling mechanical objects, generating mechanical Fock-states, and Schrödinger cat states of motion. This makes quantum acoustic devices appealing candidates for applications such as quantum metrology, information processing, and quantum memory.
This thesis focuses on the coupling between a planar superconducting transmon qubit and a high-overtone bulk acoustic resonator (HBAR) and explore its possibilities. Here,experimental demonstrations are shown where the transmon is used to drive the HBAR into a phonon lasing state making it a superconducting single-atom phonon laser. Furthermore, the transmon-HBAR device is used to probe the nature of ghost modes observed in strongly driven nonlinear systems.","cQAD; cQED; HBAR; Highovertone bulk acoustic resnotor (HBAR); Quantum acoustics; superconducting qubit; transmon","en","doctoral thesis","","978-90-8593-588-9","","","","","","","","","QN/Steele Lab","","",""
"uuid:b4066b14-7087-4ab7-8628-e7a2af4a2b83","http://resolver.tudelft.nl/uuid:b4066b14-7087-4ab7-8628-e7a2af4a2b83","Developing and implementing toolbox integrations for storing excess heat generated by a PVT system","van Rossum, Aron (TU Delft Electrical Engineering, Mathematics and Computer Science)","Santbergen, R. (mentor); Ul Abdin, Z.U.A. (mentor); Delft University of Technology (degree granting institution)","2024","This thesis addresses a critical challenge in the field of renewable energy, focusing on the efficient utilization of Photovoltaic-thermal (PVT) systems. Despite their promising role in sustainable energy production, PVT systems often grapple with excess heat generation, impacting their efficiency and longevity. The primary objective of this research is to explore the synergy between PVT modules and heat storage systems. It aims to develop and implement solutions for effectively storing this surplus heat. This work involves the formulation of new models for heat storage solutions and their assimilation into the PVMD Toolbox, housed within the Photovoltaic Materials and Devices research group at TU Delft. By enhancing the capability of PVT systems to manage excess heat, this thesis contributes to optimizing these systems for broader applications in sustainable energy generation.
This study investigated the cation competition in electrodialysis and bipolar membrane configuration regarding the ammonia removal efficiency and the overall energy consumption. The research questions were focused on the effect of enriched solutions with cations on ED and BPC to the efficiency parameters, to the impact of cation composition in the feed solution when NH4+, Na+, K+, Mg2+ and Ca2+ are included in an ED and finally, the effect of municipal reject water cation molar ratios in a combined ED and BPC configuration. The experiments included batch mode systems, with several mass and molar ratios of NH4+ applied, the above-mentioned parameters were measured. More specifically, BPC and ED configurations were tested with mass ratios of other cations in an enriched NH4+ solution, while molar ratios were tested in case of an ED configuration with NH4+, Na+, K+, Mg2+ and Ca2+ be present in the feed solution. Finally, the two configurations were tested in a sequence batch, with ED to be the pretreatment step and BPC the final stage. The phenomena that were also investigated were proton production from bipolar membranes and EC pattern on the diluate solution in this case.
In ED removal efficiency was presented as a linear curve on time while in BPC the same value took a logarithmic trend, which is attributed to proton production and finally competition. During BPC operation, there was constant production of H+ through water dissociation that led to the acidic environment in the diluate solution but also to stabilization of EC when H+ presence was dominant. In addition, in molar ratio experiments with the application of ED, removal efficiency was higher for more challenging reject waters compositions such as molar ratios between 0.30 and 0.60. Considering 75% removal efficiency as an effective case, percent demineralization was also calculated. For removal efficiency below the effective case, percent demineralization presented a minimum for molar ratio of 0.60, while for higher removal efficiency the overall trend was slightly different, having a more exponential shape. Finally, energy consumption in molar ratio experiments, for removal efficiency of 75% presented a gradual decreasing linear trend with the increase of molar ratio.
Based on the results occurred in batch experiments, a sequence batch of ED to concentrate the feed solution was established, by applying the more challenging molar ratios of 0.30, 0.45 and 0.60 and the concentrate was then fed to a BPC to explore the proton effect in a concentrated solution. The percent demineralization and removal efficiency remained stable during the experimental phase while transport number had a notable increase with the increase of molar ratio, remaining approximately the same in every individual batch. Moreover, energy consumption had an important increase with the decrease of molar ratio due to the high membrane resistance and the observed scaling effect.
Models to assess the transverse stability of timber terraced houses are simple schematizations with hand calculations of the decoupled and coupled timber terraced houses and FE models of decoupled timber terraced houses with and without T-section and coupled timber terraced houses with and without T-section. The coupling of the houses can be achieved by 4 Straviwood Modulink 6.0 kN connections per floor level. The T-section can be realised with double screws with diameter 𝑑 = 12 𝑚𝑚 with a spacing of 𝑠 = 100 𝑚𝑚.
Simple schematizations with hand calculations of the decoupled and coupled timber terraced houses result in overdimensioning of the connections since bending of the floors due to deformation of the stability wall, providing resistance to the deformation of the stability wall, is not considered. This resulted in 6 hold downs per CLT stability wall.
Compared to the FE model of decoupled timber terraced houses without T-section, all FE models have a positive influence on the design of connections in terms of reduction of number of hold downs and improvement of the total tension support reaction. Coupling of the houses is better compared to application of a T-section for decoupled houses. An improvement of the total tension support reaction of 83% and 67% for respectively the house on the left and the house on the right, compared to the decoupled timber terraced houses without T-section, can be achieved by coupled timber terraced houses with T-section. This also resulted in a reduction of 5 hold downs per CLT stability wall and the possibility to reduce the thickness of the CLT stability wall.
Results show that DLC abrasive wear behavior is predominantly plowing. Increasing normal load results in wear debris at the edge and inside the wear scar. Failure occurs between DLC and substrate (in this case SiC), upon further increasing the normal load which is in agreement with the literature. In addition, it is found that strain rate influences DLC wear behavior with increasing normal load. This implies that DLC/SiC interfacial adhesion strength presents strain rate dependency rather than DLC itself. This is supported by nanoindentation measurements, where no strain rate dependency was observed. Therefore, for a DLC coating operating under high loading (≥100mN per asperity) in an engineering application, single-asperity testing is not representative of the engineering application. This is caused by the limitations of single-asperity test setup reaching strain rates close to that of the engineering application.
Further, it is reported that in multi-asperity scratching tests increasing the normal load affected the scratch density rather than scratch depth and width. This implies that there is a range of macroscopic normal loads that corresponds to similar single-asperity wear behavior. Scratching tests performed at the edge of DLC/SiC wafers showed that edge wear depends on the rate of change of asperity interference (ω ̇) during collision with the edge. Moreover, an analytical model was developed which predicts that minimization of the impact force (and thus wear) is accomplished when ω ̈ takes minimum value. Based on this criterion minimized edge wear takes place when the asperities are relatively sharp (~1μm) and their initial interference does not exceed 30% of the coating thickness.
The model will be constructed by first reviewing the motion of a single 3D pendulum, followed by the motion of a double 3D pendulum. For both situations the Lagrangian method is used to construct the equations of motion. Semi-Implicit Euler is used as integration scheme for the discretization of time. The results provide insights into the chaotic and complex characteristics of pendulums.
Thereafter, a model for a string will be constructed and this model is eventually expanded to a model for a mussel dropper by adding constraints to the last pendulum of the string. The method used for these models was different than for the model for a single and double pendulum due to instability issues. For the string Newton's second law was used to determine the equations of motion, since using this method made it easier to apply external forces and constraints to the system. Instead of a semi-implicit integration scheme an implicit one was used, resulting in an improved stability of the system. Due to the switch from semi to a fully implicit integration scheme, a nonlinear solver was build to solve the set of nonlinear equations at every time step. Later on, it was noticed that the implicit scheme accounted for too much numerical damping. In order to reduce the numerical damping, the Crank-Nicolson method combined with the theta-method was applied.
After constructing the model, an experiment was conducted for validating the model and for determining the damping coefficient of the system, which was still unknown. The experiment consisted of a physical model of the dropper and a camera which recorded the motion of the physical model. A code was written to determine the position of the pendulums in each frame and these positions were calculated relative to the angle each pendulum made with the horizontal axis. The experimental setup was reconstructed by the numerical model and compared in order to determine a value for the linear and quadratic damping coefficients. The model overdamped the amplitude of the motion right after the dropper was released from its equilibrium position. This could be due to numerical damping, due to errors in the experiment or due to a faulty translation of the experiment to the model. This provides the numerical model with not enough damping to let the motion die out, but it better represents the behaviour of the dropper for larger motions. These coefficients were found to be most suitable because from an engineering perspective it is safer to underestimate the damping in the system and assume higher amplitudes of the motion.
Lastly, the 3D model is used to simulate a mussel dropper in waves, as was the aim of this research. The dimensions of the mussel dropper are chosen to represent a real-life mussel dropper. The sea state to which the mussel dropper is subject will be one occurring every once in 25 year in the North Sea. The mussel dropper is simulated using seventeen pendulums. One pendulum is reviewed to determine the response of the mussel dropper. The time signal of this pendulum and the response spectrum of the pendulum show how the pendulum reacts to the incoming waves. A phase space plot is constructed to visualize the chaotic and complex behavior of the mussel dropper in waves.
The Dutch government aims to reduce emissions of greenhouse gasses in the aviation industry. This incentive resulted in a collaboration called the ‘Actieagenda Trein en Luchtvaart’. Their ambition is to strengthen international trains, by making them more attractive alternatives to short-haul flights. Specifically, the route between Amsterdam Airport Schiphol and Brussel Zuid train station. On this route KLM is working together Thalys to offer a service to combine flight and train tickets. This service is called: Air-Rail. The challenges of Air-Rail lie within the transfer that differs from traditional Air-Air, using non-Air-Rail facilities, and a complex stakeholder network.
Research is done to understand how the Air-Rail transfer service can be improved to better suit the needs for Air-Rail transfer passengers. This done by experiencing the Air-Rail journey first-hand between Copenhagen and Brussels. As well as, analyzing the results of a research report about the Air-Rail passenger’s experiences.
Three main issues are to be concluded from research: 1. Pre-travel info, 2. Missing signage, 3. Baggage. From these three issues, it can be concluded that pre-travel info and missing signage require short-term solutions due to being involved with a singular or small number of stakeholders. However, baggage requires a long-term solution based on the complexity of the vast stakeholder network that is involved. Therefore, the main issue to solve is baggage. By creating a focus on a long-term plan, while in the meantime the low-hanging fruit (pre-travel info and signage) is picked to create a fully seamless and complete Air-Rail service.
Subsequently, concepts are generated for baggage by organizing an Air-Rail stakeholder workshop and interviewing representatives from an Air-Rail rail operator and an Air-Rail airline. The result is a list of generated concepts. From this a selection is made, to find the best and most fitting baggage concept. This is done by having representatives from an Air-Rail airline and airport, assess by filling in Harris profiles for the concepts. This is done with potential Air-Rail travelers as well, who vary in international train travel experience.
The outcome for the first horizon in 2025, is a temporary door-to-airport baggage delivery service. This service transports Air-Rail baggage by delivery van between Brussels and Amsterdam Airport Schiphol and vice versa. The outcome for the second horizon in 2032, is a permanent concept of designing a new train for Thalys that includes a fourgon. A fourgon is a train compartment where Air-Rail baggage can safely and separately be stored. Both solutions create a secure and convenient way of handling baggage during Air-Rail travel between Brussel Zuid and Amsterdam Airport Schiphol.
In the final roadmap design, it is elaborated how to implement these concepts. The roadmap specifies what the main product/service is and what is needed to support it. Additionally, the roadmap shows the tasks for Air-Rail stakeholders needs for a successful Air-Rail service.","Air-rail; Intermodal; Baggage; High-Speed Rail; Short-haul flights","en","master thesis","","","","","","","","","","","","Strategic Product Design","",""
"uuid:655fce08-75b7-4e90-9f22-3f792f9a8a99","http://resolver.tudelft.nl/uuid:655fce08-75b7-4e90-9f22-3f792f9a8a99","Green Bond Valuation: A Numerical Mathematics Perspective: Assessing the Influence of Environmental Factors","Rutten, Jurriaan (TU Delft Electrical Engineering, Mathematics and Computer Science)","Vuik, Cornelis (mentor); Dwarka, V.N.S.R. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis presents a novel approach to the pricing of green bonds, a growing segment in financial markets with an emphasis on environmental sustainability. Unlike traditional financial instruments, green bonds uniquely incorporate environmental considerations, particularly carbon price (c_t), along with traditional factors like the short rate (r_t), into their valuation. This integration is increasingly relevant in today’s economy, reflecting a shift towards sustainable finance. The core of this research involves applying advanced numerical methods, including the Finite Difference Method, Crank-Nicolson discretization, GMRES and Bi-CGSTAB, in order to develop and analyze pricing models for both green and conventional bonds. The study aims to assess how environmental factors impact the efficiency of these numerical techniques and to compare the outcomes with conventional bond models. The research reveals that green bonds, compared to conventional bonds, present unique numerical challenges, notably requiring more iterations for convergence in iterative methods GMRES and Bi-CGSTAB because of the high carbon price volatility (σc) and the ’Greenium’ phenomenon. Moreover, the comparative analysis showed that while Bi-CGSTAB outperforms GMRES in the green bond model, the opposite is true for conventional bonds. This study not only contributes to the theoretical understanding of green bond pricing but also offers practical insights for financial analysts and investors navigating this evolving market.
Keywords: Green Bonds, Bond Pricing, Zero-Coupon Bond, Short Rate Modeling, Numerical Methods, Crank-Nicolson, GMRES, BiCGSTAB, Environmental Finance, Sustainable Investing, Comparative Analysis, Financial Modeling.","Green Bonds; Bond Pricing; Zero-Coupon Bond; Short Rate Modeling; Numerical Methods; Crank-Nicolson; GMRES; Bi-CGSTAB; Environmental Finance; Sustainability; Sustainable Investing; Financial Modeling","en","master thesis","","","","","","","","","","","","Applied Mathematics | Financial Engineering","",""
"uuid:e141cdc0-8aa2-4bfe-81b8-99820c6c7f6d","http://resolver.tudelft.nl/uuid:e141cdc0-8aa2-4bfe-81b8-99820c6c7f6d","Feasibility study of a non-contact, non-destructive testing method to assess the structural integrity of synthetic mooring ropes","Jongejan, Jasper (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Ship and Offshore Structures)","Pahlavan, Lotfollah (mentor); Riccioli, F. (mentor); Huijer, A.J. (mentor); Grammatikopoulos, A. (graduation committee); Bosman, Rigo (graduation committee); Delft University of Technology (degree granting institution)","2024","Governments are looking more and more to invest in renewable energy sources due to the energy transition that is currently taking place. One of the many renewable energy sources is wind energy which is increasingly positioned at sea. Wind turbines in deep parts of the ocean can be placed on floating structures which are often moored to the sea bottom by mooring ropes. For deep sea, the only viable option is a synthetic mooring line due to its almost neutral buoyancy.
Mooring ropes have a vital role in the offshore floating structure as it is keeping the structure in place. When a mooring line breaks, the consequences may be big, leading to serious damage or dangerous situations. Therefore, the structural integrity of mooring ropes should be evaluated regularly. For synthetic mooring ropes, the only method at this point in time is visual inspection. This can be done by divers or by Remotely Operated Vehicles (ROVs). This method is expensive, time consuming and in case it is done by divers, it is potentially dangerous. Furthermore, synthetic mooring ropes are susceptible to external damage which means inspection would have to be executed without direct contact with the mooring ropes. Therefore, it is necessary to assess the feasibility of a non-contact, non-destructive testing method in order to assess the structural integrity of a synthetic mooring line. The combination of non-destructive material property assessment and tension assessment is believed to produce a structural health monitoring instrument for synthetic mooring ropes.
In this thesis, a methodology is proposed which uses two independent non-contact, non-destructive measurements to assess the structural integrity of a high modulus polyethylene (HMPE) rope specimen. The measurements involved are ultrasonic guided wave (UGW) measurements and vibration measurements. The UGW measurements are performed to assess the stiffness of the test specimen according to the principle of attenuation of ultrasonic waves propagating through a specimen. The vibration measurements are performed to assess the natural frequencies of a manually excited test specimen. The assessed natural frequencies and the determined stiffness of the test specimen can be used to calculate the load acting on the test specimen.
The methodology is tested by conducting experiments in a laboratory environment where in-situ conditions are recreated by performing the tests underwater. It was concluded that the loads can be recalculated with varying accuracy of approximately 10% with respect to the actual values, with increasing accuracy for higher load values. It is concluded that the proposed methodology has the potential to determine load on a synthetic mooring line in a non-contact, non-destructive manner.","Non-Destructive Evaluation Techniques (NDT); Synthetic mooring ropes; Non-contact; Ultrasonic measurements; Vibration analysis; Stiffness prediction; Tension prediction","en","master thesis","","","","","","","","2025-02-14","","","","Marine Technology | Ship and Offshore Structures","",""
"uuid:3937b4ff-d42a-4aef-94e8-6e0d4a212dd4","http://resolver.tudelft.nl/uuid:3937b4ff-d42a-4aef-94e8-6e0d4a212dd4","Impact of solar eclipses on NO2 in the Earth's atmosphere as measured from space by TROPOMI: Understanding the sensitivity of the Earth's atmospheric composition to short-term variations in sunlight","Schrijver, Jelle (TU Delft Civil Engineering & Geosciences)","Trees, V.J.H. (mentor); Veefkind, j. Pepijn (graduation committee); de Roode, S.R. (graduation committee); Unal, C.M.H. (graduation committee); Stam, D.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","During a solar eclipse, sunlight incident on the Earth is reduced due to the (partial) shadow of the Moon. Atmospheric trace gas concentrations which are influenced by the amount of available sunlight, such as nitrogen dioxide (NO2), may be affected due to the disrupted photolysis processes. Large-scale observations of the increased NO2 concentrations caused by the solar eclipse would improve our understanding of the sensitivity of NO2 in the atmosphere to short-term variations in sunlight. Spaceborne
measurements can provide valuable information about the large-scale spatial distribution of NO2, which is provided daily by the TROPOMI instrument aboard the Sentinel-5 Precursor satellite by measuring and retrieving locally reflected sunlight. However, the TROPOMI NO2 retrieval is unable to derive reliable concentrations during a solar eclipse, as solar eclipses are not taken into account in its retrieval algorithm. In this research, we have adjusted the NO2 retrieval of TROPOMI such that it can handle solar eclipses and study the large-scale response of NO2 during two solar eclipses over Europe in 2021 and 2022. We found a large-scale increase of NO2 in the adjusted measurements, which linearly correlated with the degree of obscuration. We compared the measured NO2 increase with the values from the atmospheric chemistry model TM5 including an applied eclipse implementation and we found a close agreement in most areas that are not highly polluted. Our measurements and model predict a NO2 increase of 60%±12% and 70%±7% for an obscuration fraction of 1, respectively. More advanced chemistry modelling work is needed to explain the measurements in highly populated areas. We conclude that our results demonstrate that the TROPOMI algorithm is capable of correctly measuring NO2 after an adjustment of the NO2 retrieval. We have shown that it is possible to adjust an atmospheric trace gas retrieval for the influence of a solar eclipse. Moreover, we are the first to provide evidence for an increase in NO2 during a solar eclipse using space-based measurement techniques and to quantify this increase on a large scale with the same instrument. Our measurements can be used to test atmospheric chemistry models, possibly improving their sensitivity to solar eclipses but also artificial shadows on the Earth induced by sunlight-intercepting geoengineering approaches.","Atmospheric Remote Sensing; TROPOMI; Remote Sensing; Data Analysis; NO2; Solar eclipse","en","master thesis","","","","","","","","","","","","Geoscience and Remote Sensing","",""
"uuid:5ece7927-05ac-4d62-9dcf-58a8ffbc7055","http://resolver.tudelft.nl/uuid:5ece7927-05ac-4d62-9dcf-58a8ffbc7055","Digital transformation in healthcare: Designing an intervention to facilitate the implementation of the BgZ by bridging the gap between healthcare & policy","Kroon, Lisa (TU Delft Industrial Design Engineering)","Albayrak, A. (mentor); Jansen, A.J. (graduation committee); Kok, Petra (mentor); Grootswagers, Barbara (graduation committee); Delft University of Technology (degree granting institution)","2024","Problem definition
The healthcare sector faces escalating pressure due to its current inefficient practices in digital information exchange. The Integral Care Agreement (IZA) from the Ministry of Health, Welfare, and Sport (VWS) and overarching healthcare organizations is focused on creating a future-proof healthcare system. The Wegiz, introduced within the IZA, outlines standards for electronic data exchange among healthcare providers, with the focus on the Basic Dataset for Care (BgZ). However, the implementation of BgZ faces challenges, as insight in the influencing factors and facilitating interventions are limited.
Research outcomes
This research addresses this gap by employing literature reviews, (semi-structured) interviews, observations, and a thematic analyses within the healthcare ecosystem, specifically focused on the experience of medical specialists with the current organization of digital information exchange, to identify the factors affecting the BgZ implementation. A critical finding reveals a disconnect between macro-level legislation and micro-level healthcare practitioners, resulting in an oversight of the human aspect in decision-making and communication of changes. Furthermore, VWS encounters challenges in effectively engaging the target audience, according to medical specialists and organizational employees, leading to various disadvantages, including negative experiences with legislatively driven developments and a lack of awareness among healthcare professionals regarding BgZ and their pivotal role in the transformation. Furthermore, the limited awareness for standardization among specialists and the time and efficiency constraints are additional factors to be taken into account. Although, legislation is obliging interoperability between systems on a technical level, including the human aspect to evoke behaviour change towards standardization is currently limited. The cultural factors of the medical environment are challenging as well as autonomy and hierarchy is deeply rooted, which may influence the attitude towards change.
Design goals
The study emphasizes the need to involve healthcare professionals, starting with the first step of engaging physicians in the change process. To address this, a serious game has been developed with the primary goal of raising awareness about the urgency of BgZ implementation and encouraging active participation and collaboration by provide positive experiences of the opportunities the BgZ includes. The game, evaluated through sessions with the target audience, has proven to be an effective intervention, achieving its set objectives.
Recommendations
As a recommendation, the game should be implemented in an interdisciplinary manner, involving physicians, assistants, IT personnel, organizational staff, and policymakers. This approach aims to connect perspectives and foster collaboration. Ultimately, the game serves as a tool to bridge the gap between policymakers and healthcare practitioners by providing insights into each other’s perspectives, fostering a collective and collaborative approach towards successful BgZ implementation.
The results from direct charging of the qubits align with existing literature. Charger-mediated energy transfer is demonstrated through the characterisation of the CNOT gate as an interaction gate, gaining the same amount of stored energy, but with a significant increase in the charging time, resulting in a lower charging power. Furthermore, our findings demonstrate that parallel charging of an array of qubits preserves the quality of direct charging of the individual qubits.
To our knowledge, this work presents the first results of charger-mediated energy transfer in real quantum devices. Charger-mediated energy transfer can be interesting for specific applications such as quantum metrology, where preserving the quantum state is critical. Additionally, this is the first demonstration of parallel charging of superconducting transmon qubits in the QB context, giving promising results for the scalability of superconducting transmon qubits as QB. Our study paves the way forward to implementing quantum batteries for energy management in quantum technologies, a near-term future application of quantum batteries.","Quantum battery; Quantum thermodynamics; Quantum Computing; Quantum Inspire; Charger-mediated energy transfer; Parallel charging; Battery; Transmon qubits; Direct charging","en","master thesis","","","","","","https://github.com/mvannederveen/quantum-battery-thesis/","","","","","","Applied Physics","",""
"uuid:db566cfb-2968-4caa-850a-e2107a64cc0b","http://resolver.tudelft.nl/uuid:db566cfb-2968-4caa-850a-e2107a64cc0b","Acoustic Side-Channel Attacks on a Computer Mouse: Predicting Mouse Movements through Emitted Audio","Duroyon, Marin (TU Delft Electrical Engineering, Mathematics and Computer Science)","Conti, M. (mentor); Tsudik, Gene (mentor); Orazi, Gabriele (graduation committee); Delft University of Technology (degree granting institution)","2024","Acoustic side-channel attacks (SCAs) use audio produced by a system to bypass traditional security measures to extract sensitive information. Human interface devices, such as keyboards, have been the focus of such attacks, however, computer mice are input devices that are currently in a research gap. This paper explores the security risks the emitted mouse sounds pose during usage. The methodology first establishes a proof of concept attack by classifying the mouse movement into up, down, left and right directions. The results lead to a 97% accuracy in distinguishing between the four categories in a controlled environment. This sets the stage by proving a leakage model useful for mouse acoustic SCAs. The research investigated the precision of tracking mouse movements by conducting experiments with ten unique movements on a large mouse pad. The study, using a dual-microphone setup, a smartphone in stereo recording, achieved 95% accuracy in discerning ten different movements. Furthermore, to place the research in a real-world context, the same experiment was repeated by adding two more directions (diagonal movement) and five other participants. The model was trained to become generalizable to six participants and 12 mouse pad movements, resulting in an accuracy of 94%. Given the same environment, this result shows the capability to extract sensitive information using a non-user-specific model. In addition, the paper experimented with a realistic attack scenario to infer a user action of closing a window on a laptop by clicking the red 'X' at the top right of the screen. The trained model could predict with 91% whether a mouse movement and click described the close window event. The experiments and findings within this research confirm audio leakage from a computer mouse in use. Moreover, the SCA poses a security risk in real-world scenarios, as it allows us to trace user activity in a realistic scenario. This work has explored the limits of single microphone use for SCAs and opened the door toward dual-microphone setup for future experiments.","Cybersecurity; Side Channel Attacks; Security; Machine Learning; Mouse; Human Interface Devices","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:8ac0ba80-25b2-4ef1-b1bf-f0aa1b3d8e97","http://resolver.tudelft.nl/uuid:8ac0ba80-25b2-4ef1-b1bf-f0aa1b3d8e97","Investigating the effect on departure capacity of changing Target Off-Block Time uncertainty","Snijders, Daan (TU Delft Aerospace Engineering)","Ellerbroek, Joost (mentor); Hoekstra, J.M. (graduation committee); Dijkstra, F. (graduation committee); Roling, P.C. (graduation committee); Delft University of Technology (degree granting institution)","2024","With its 500.000 flights per year, Schiphol Airport is one of the busiest airports in Europe. Efficient runway use is vital for a smooth day-to-day operation. This paper investigates the new runway scheduler at Schiphol Airport, also referred to as the Departure Manager (DMAN). The new DMAN is built for a better utilisation of the outbound capacity with a higher predictability. This study aims to verify whether positive behaviour regarding earlier Target Off-Block Time (TOBT) updates leads to the desired results in capacity, predictability and reduced delay, based on historical data. An experimental model was used to simulate a new Departure Manager (DMAN), which uses a set of priority rules to assign flights to the runway slot in which they depart. The simulation did not find an overall significant result for all cases, runways and months, due to the averages influenced by the size of the data. However, a positive trend can be seen in the presented results, indicating that earlier TOBT updates lead to a better runway schedule. One cannot schedule better than on time, but late TOBT updates accumulate like a snowball effect throughout the planning.","ATC; Runway Capacity; Runway schedule; Air Traffic Control; Airport Operations","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:b2d1745f-7c71-4dc5-b9fb-bcc4dc1cb891","http://resolver.tudelft.nl/uuid:b2d1745f-7c71-4dc5-b9fb-bcc4dc1cb891","Improving Bank Angle Representation on the Primary Flight Display Using Static Monocular Depth Cues: Evaluating the effect of static monocular depth cues on attitude indicator interpretation using misleading motion cues","Van Droogenbroeck, Chloë (TU Delft Aerospace Engineering)","Landman, H.M. (mentor); Stroosma, O. (mentor); Mulder, Max (mentor); van Paassen, M.M. (mentor); Delft University of Technology (degree granting institution)","2024","Roll reversal errors, where the pilot tries to steer the aircraft back to wings-level but unintentionally increases the bank angle instead, have contributed to several accidents. Previous studies have shown that these errors can be caused by misinterpreting the attitude indicator (AI), with the figure-ground relations cited as contributing to this misinterpretation. A modified AI was developed, which uses several static monocular depth cues (color gradient, linear perspective lines, and shadow-light relationship) to strengthen the figure-ground relationship.
The modified version of the AI was compared to a baseline AI in a two-part flight simulator experiment where pilot reaction time and error rate, severity, and duration were measured. The first part induced the leans illusion making use of physiological adaptation to roll angle, distraction, and surprise. The second part simulated the leans illusion by simply rolling the simulator to the left or right. A group of 25 experienced commercial airline pilots performed a roll-to-level task in a moving-base simulator, which also provided spatially disorienting motion cues, using both the baseline and modified versions of the AI. While the modified
display had a lower error rate in the motion-opposite scenario when using the novel method (4.91% compared to 6.07%), no significant difference was found between the error rate of the two displays. The only significant difference was found in the reaction time, where the modified AI caused an increase in reaction time. The error rates and reaction times of the first part of the experiment did not match previous research. The novel disorientation method seemed to work best in a surprise scenario. While no significant differences were found between the modified AI and the baseline AI, it is still recommended to continue testing the modified AI with a new experiment setup, especially analyzing its effect in more extreme attitudes.","","en","master thesis","","","","","","","","2026-02-13","","","","Aerospace Engineering","",""
"uuid:9f899ce2-4160-4e3c-985e-3a8664620253","http://resolver.tudelft.nl/uuid:9f899ce2-4160-4e3c-985e-3a8664620253","Pull-out force of grippers with initially-curved fingers based on Pseudo-Rigid Body modelling","Kuntz, Mark (TU Delft Mechanical, Maritime and Materials Engineering)","Herder, J.L. (mentor); Huisjes, A.E. (mentor); Broeren, F.G.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis presents the state-of-the art gripping literature and the implementation and extension of an existing Pseudo-Rigid Body Modelling (PRBM) method for modelling initially-curved compliant grippers out of which a circular object is extracted. From the existing literature, challenges are found in the design and evaluation of concepts of initially-curved compliant grippers, mainly involving the relevant design parameters, such as the thickness and enclosing angle of the finger.
The main goal of this thesis is therefore to present and validate the pull-out force modelling for these fingers within defined load conditions to provide comprehensive insights into the relation between important design parameters, such as the enclosing angle and thickness of the finger.
This goal is accomplished by extending an existing 3R PRB-model for initially-curved beams with a fifth link that represents the object and analysing the kinematics and kinetics to determine the relation for the pull-out force of a gripper finger with defined dimensions and a known load case.
This model is validated by designing and building an experimental test setup in which the reaction forces of a initially-curved testpiece of PLA and stainless steel material are measured. Errors for the kinetics between 12 and 32 percent were determined, consisting primarily of systematic errors.
The validated model is used for a parametric study, where relations between relevant design parameters, such as the enclosing angle and thickness of an initially-curved compliant gripper finger, are determined and visualized in a design chart that are be applied in the design of an initially-curved enclosing gripper prototype.","Pseudo-Rigid Body Modelling; Pull-out force; Initially-curved gripper; Parametric study","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Mechatronic System Design (MSD)","",""
"uuid:de917646-6c9a-41b1-a6f8-c87657dd40ca","http://resolver.tudelft.nl/uuid:de917646-6c9a-41b1-a6f8-c87657dd40ca","From a strategy and innovation agency to a venture building powerhouse","van Laar, Colin (TU Delft Industrial Design Engineering)","Simonse, LWL (mentor); Buijs, M.J.J. (graduation committee); Yousif, Arsham (graduation committee); Delft University of Technology (degree granting institution)","2024","In a rapidly changing business landscape, innovation has become a critical priority for companies, with start-ups outpacing traditional corporations in speed and agility to innovate. Despite their potential, these start-ups often face high failure rates and struggle to cross the “valley of death” due to gaps in resources and commercialization expertise. To address these challenges, new venture building models such as the venture studio and venture clienting model have emerged, aiming to systematically de-risk new ventures and support them in successfully commercializing their innovations. This thesis explored these models, seeking to bridge the gap between practical applications and academic research, with the goal of developing a new model that enhances start-up success by reducing failure risks, improving time-to-value, and optimizing cost and performance. This graduation project for Business Models Inc. explored different venture building models to identify and design the most optimal model for BMI to introduce into their portfolio of service offerings. Utilizing the Double Diamond methodology (Design Council, 2005), the project began with a research phase involving a literature review and expert interviews, focusing on venture building, corporate venturing, and factors influencing start-up success and failure. This phase led to the identification of the start-up studio model as highly beneficial for BMI, due to its potential for high financial value and control over start-ups’ strategic direction. Insights from the research highlighted three critical pillars for building strong ventures: the Human factor, the Resource factor, and the Opportunity factor. Interviews revealed three key stakeholder archetypes that are relevant for designing a new venture building model for BMI: the Driving Force, the Investor, and the Supporter. The second phase of the project, the design phase, transformed these insights into a tangible value proposition named “the Studio”. This startup studio model for BMI is designed to scout technologies, ideate and validate radical venture ideas, assemble the ideal founding teams, and provide ongoing support to ensure growth. It aims to mitigate risks associated with the three identified pillars by involving a diverse mix of individuals in the founding teams, offering initial investment, and support with studio services. The outcome includes a pitch deck to communicate the studio model’s benefits to stakeholders, a minimum viable organization structure with necessary roles and capabilities, financial forecasts, and a roadmap for implementing the studio model at BMI.","Venture Building; Start-up studio; consultancy; value proposition; Roadmap","en","master thesis","","","","","","","","","","","","Strategic Product Design","",""
"uuid:22be7288-d5cb-4eda-b8c8-e7e498b1e8c6","http://resolver.tudelft.nl/uuid:22be7288-d5cb-4eda-b8c8-e7e498b1e8c6","Organ-on-Chip Platform with Transient Membrane for Vascularisation of Brain Organoids","Kahler, Friso (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Electronic Components, Technology and Materials)","Boutry, C.M. (mentor); Sarro, Pasqualina M (graduation committee); Savva, A. (graduation committee); Accardo, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","br/>Organ-on-Chip (OoC) is a technology that aims to increase the efficiency of drug development processes and organ models by engineering well-defined cell culture environments. Physiological relevant mechanical, chemical, or electrical cues provide in vivo-like microenvironments for realistic cell maturation. Biodegradable technologies have gained attention for the development of novel OoCs by integrating transient features to the culture platforms imitating the ever-changing environment inside the human body. Current efforts to replicate durable brain tissue models from organoids are limited by the lack of sufficient vascularisation introducing cell necrosis inside the 3D cell culture.
This report presents the design and fabrication of a 3D-printed OoC-platform that combines two independent cell protocols for a Vessel-on-Chip and a cortical brain organoid. The microfluidic chip is embedded with a biodegradable membrane, that separates the two cell cultures for a strictly defined time period. The membrane, composed of bayberry wax, lanolin, and carbonyl iron particles, enables the controlled opening via alternating magnetic field exposure. The thermal behaviour of the membrane is analysed with DSC and the magnetic particles with a SQUID magnetometer. Inductive heating experiments determine the optimal composite composition and exposure profile to facilitate membrane opening and subsequent communication between neural and vascular cells. The integrated membrane proved to be successful during the injection and evacuation phase. This positive result paves the way for co-culturing two inherently different cell protocols on a single chip. This master project lays the foundation for collaborative efforts towards vascularised brain organoids-on-chip and showcases the potential of additive manufacturing and biodegradable materials in OoC technology.","","en","master thesis","","","","","","","","2025-02-14","","","","Biomedical Engineering","",""
"uuid:7882df26-b0e6-4e23-8dd6-f5fa72884d53","http://resolver.tudelft.nl/uuid:7882df26-b0e6-4e23-8dd6-f5fa72884d53","Simulating Quantum Scheduler Performance for an Entanglement Generation Switch","Talsma, Marit (TU Delft Electrical Engineering, Mathematics and Computer Science)","Wehner, S.D.C. (mentor); Gauthier, S.S. (graduation committee); Delft University of Technology (degree granting institution)","2024","The quantum internet improves upon the classical internet with several new possibilities. However, to create such a quantum internet, metropolitan hubs (for this research we will use an Entanglement Generation Switch - EGS - as hub) are needed to avoid a scaling problem when connecting all end nodes individually with one another. These EGSs share resources for multiple end nodes. Hence, resource sharing protocols are needed to manage these resources. Unfortunately due to the probabilistic nature of end-to-end entanglement generation, classical resource sharing protocols will not suffice for implementation in a quantum network. Therefore the need to design quantum resource sharing protocols arises. These protocols, where we specifically investigate quantum schedulers, should be simple and predictable to provide a comprehensible addition to current research by incorporating more parameters into the current EGS model while still attempting optimal resource efficiency. In this research we have extended quantum network simulation software to be used in this research and following projects. We have implemented a classical Max Weight scheduler with a constant time window size to simulate the inefficiency of such a classical protocol in a quantum environment and improve upon this protocol by implementing a scheduler with a dynamic time window size which scales with the link length and the probability of a photon arriving at the EGS. We investigate the entanglement successes, idle time and entanglement rates when using these schedulers and compared these with each other and with a third scheduler without a time window size but using a cutoff timer instead, the Cutoff scheduler. These results show an optimality of entanglement successes, idle time and entanglement rates for the Cutoff scheduler over the Dynamic Time Window scheduler and for the Dynamic Time Window scheduler over the Max Weight scheduler with a constant time window size. Also a decrease in entanglement rate for all schedulers is shown when increasing the link length.","","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:d994ff91-0c51-4e31-bda2-b76fa5f6db31","http://resolver.tudelft.nl/uuid:d994ff91-0c51-4e31-bda2-b76fa5f6db31","SZFitter: Predicting DESHIMA 2.0 observations of the thermal Sunyaev-Zel’dovich effect","Amaldi, Emilio (TU Delft Applied Sciences)","Endo, A. (mentor); Moerman, A. (mentor); Karatsu, K. (mentor); Steele, G.A. (mentor); Delft University of Technology (degree granting institution)","2024","class=""MsoNormal"">Galaxy clusters are some of the largest known structures in the universe. Studying them observationally and theoretically can provide a lot of information on how these clusters form and are structured. One way to study them is through the so-called Sunyaev-Zel’dovich (SZ) effect, which is an interaction between the cosmic microwave background (CMB) and hot electrons in the cluster medium. The SZ effect can be further broken down into a thermal component (tSZ) arising from the random motion of the electrons, and a kinematic component (kSZ) arising from the bulk motion of the cluster medium, making it a good probe for several properties of the cluster. The SZ effect can be observed as a distortion of the CMB spectrum using submillimeter spectrometry. However, at many submillimeter frequencies radiation is absorbed strongly by the atmosphere. This makes it hard to interpret the measured SZ signal, and measurements require long observation times in order to reach a sufficient signal-to-noise ratio. In this thesis, we present a framework that simulates a submillimeter spectrometer observation of the tSZ effect including noise factors. It then fits a model tSZ signal to the noisy signal. This allows us to investigate the relation between observation time, noise and retrievability of cluster properties. We simulate a galaxy cluster with an electron temperature 𝑇𝑒 = 15.3 keV and central optical depth 𝜏𝑒 = 0.0172 with two simulated DESHIMA-type filterbanks spanning different frequency ranges. For each filterbank we perform 20 simulations with an observation time of 16 hours each, and 20 simulations of 32 hours. We fit every simulation separately, but average over simulations to obtain an expectation value for 𝑇𝑒 and 𝜏𝑒 given a filterbank and observation time. We also repeat each fit over rebinned copies of the noisy spectra, combining 7 data points into each bin. All tested combinations of filterbanks and observation times produce fits with results that are consistent with the input parameters. The 160-320 GHz filterbank consistently gives lower errors than the 220-440 GHz filterbank. From rebinning, we do not find any significant improvement or degradation of the quality of the fits. The estimates obtained from rebinned data deviate very little from the original estimates, by at most 5%, and show no change in consistency. From this result, we conclude that SZ observations using DESHIMA 2.0 could provide estimates on cluster parameters. These estimates are already consistent after 16 or 32 hours of observation time. However, we recommend a new filterbank design that covers 160-320 GHz since the error on estimates using this range are smaller than the errors obtained using the original 220-440 GHz filterbank. This is likely due to the atmosphere absorbing much less radiation at this frequency range. Additionally, the results from rebinning show that this new filterbank could contain fewer filters with a lower resolving power without degradation of fit quality.","Sunyaev-Zeldovich effect; DESHIMA; Submillimeter astronomy; Numerical Simulation; Spectrometer; MKIDs","en","bachelor thesis","","","","","","","","","","","","Applied Physics","",""
"uuid:37c19d00-fad3-4f52-9401-cdcb964afdb2","http://resolver.tudelft.nl/uuid:37c19d00-fad3-4f52-9401-cdcb964afdb2","Life-Cycle Assessment for Sustainable Inland Shipping on South Holland's Waterways","van der Knokke, Quan (TU Delft Technology, Policy and Management; Institute of environmental sciences (CML), Leiden University)","Pruyn, J.F.J. (graduation committee); van Oers, L.F.C.M. (mentor); Vonk, Ewald (graduation committee); Delft University of Technology (degree granting institution); Universiteit Leiden (degree granting institution)","2024","Inland shipping is an efficient way of freight transportation, especially in the Province of South Holland (the Netherlands), but this sector faces a significant challenge in further reducing climate change effects and local health and environmental impacts caused by the combustion of diesel fuel.
In this study, an analysis of the inland shipping sector in South Holland and its challenges and opportunities regarding a transition to “zero-emission” shipping is performed, based on a life cycle assessment (LCA). This LCA compares the environmental impacts of the annual operations of a medium-size, short-route inland barge, comparing different engine technologies and energy carriers: diesel in a combustion engine, hydrogen (grey/blue/yellow) in a combustion engine, hydrogen (grey/blue/yellow) in a fuel cell-electric power system, and electricity in a battery-electric power system. Results are obtained for 2020, 2030, 2050, and 2100, based on the SSP2 pathway for future socio-economical development wherein the electricity grid mix decarbonises and fossil-based diesel is phased out in favour of biodiesel and synthetic diesel, and assessed using the EF v3.1 assessment family.
The results indicate that the most significant sources of emissions are barge operations (for combustion engines, especially for diesel, and most of all for older diesel engines) and the fuel supply chain (for diesel and hydrogen), as well as some contribution from the production of batteries (for the battery-electric alternative) and fuel cells (for the hydrogen fuel cell alternative). Contributions from the life cycle of the barge hull, lubricant and oil streams, and infrastructure are minor. The main contributor to climate change is CO2, and the main contributors to local health and environmental impacts are emissions of particulate matter (PM), NOx, and SOx.
For the selected case study barge, a battery-electric system provides the strongest reduction in environmental impact (climate change, acidification, photochemical oxidant formation, and PM formation) even with background data for 2020, and its advantage increases further as the electricity grid decarbonises. The battery-electric and hydrogen fuel cell systems are the only ones which can be labelled as “zero-emission”, although the life-cycle emissions of hydrogen are high in the short term and its advantage only becomes apparent beyond 2030.
Among the hydrogen variants assessed, yellow hydrogen – produced by electrolysis from the electricity grid – has the lowest life-cycle climate change impacts in the long term, although it is not a clear winner when considering local health and environmental effects (acidification, PM formation) from its production. A hydrogen fuel cell system provides a slight but consistent benefit over hydrogen combustion due to a higher efficiency and the absence of operational emissions.
Sensitivity analyses indicate that the advantage of a battery-electric solution disappears for barges transporting larger loads and sailing longer distances, due to the larger energy capacity this requires, and becomes entirely impractical for long routes, where a hydrogen fuel cell solution provides the lowest impacts overall. Hydrogen fuel cells lose their advantage over hydrogen combustion for barges requiring very high engine power due to the additional impacts from fuel cell production exceeding the reduction from emission-free operations...","LCA; Life-cycle Assessment; Inland shipping; inland water transportation; Hydrogen fuel cell electric vehicles; battery electric vehicles","en","master thesis","","","","","","https://qlcav.quan.cat/?project=inlandshipping Interactive version of results","","","","","","Industrial Ecology","",""
"uuid:31b5276f-bd9c-45ac-920f-58d589f74fc7","http://resolver.tudelft.nl/uuid:31b5276f-bd9c-45ac-920f-58d589f74fc7","Design and validation of a modular laparoscope for low-income countries: Design of a low cost laparoscope","van Loon, Rafael (TU Delft Mechanical, Maritime and Materials Engineering)","Dankelman, J. (mentor); Horeman, T. (graduation committee); Oosting, R.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","The availability of laparoscopy in low-income settings has been limited based on the requirements that have to be met to perform this type of abdominal surgery. At the same time, these regions and countries could stand to gain the most from it based on quicker recovery times and a lower chance of infections. Attempts have been made to solve this inaccessibility by minimizing the required components to perform this type of surgery at a substantially lower cost. None of these projects have resulted in a laparoscope that can compete with commercial laparoscopes regarding resolution, image quality, and critical design features such as viewing angle. Based on these shortcomings, this study aims to design a sub-500-dollar modular laparoscope for gas and gasless laparoscopy that adheres to state-of-the-art image quality and design features. The laparoscopes are designed following the 'Roadmap for Design of Surgical Equipment for Safe Surgery Worldwide”. Based on the roadmap requirements regarding the needs of patients, end-users, and stakeholders, were acquired focusing on cost, robustness, and reusability. Following the design process, two intermediate prototypes were developed, which were evaluated based on function and image quality by a laparoscopic surgeon to validate the requirements and receive design feedback. They resulted in a modular laparoscope that connects with USB to a laptop, which shares the image sensor, light source, electronics, and handle between the laparoscope for gas and gasless laparoscopy. The gasless laparoscope employs a flexible chip-on-the-tip design that can be straightened for entry through a trocar and released to set the tip angle at 30 degrees. The gasless laparoscope does not have to comply with the trocar and can enter straight through the abdominal entry point. Resulting in a chip-on-the-tip design, which is statically bent at an angle of 30 degrees. To validate the design, a laparoscopic surgeon evaluated the function and image quality, and additional tests were performed to validate the thermal and reprocessing capability. The study resulted in a modular sub-500-dollar laparoscope for gas and gasless laparoscopy, which shows great potential but requires future work to be certified and production-ready.","Laparoscopic surgery; Biomedical device; LMICs; Global surgery","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:15f5628b-9175-4ef3-8f39-41a97cb7749a","http://resolver.tudelft.nl/uuid:15f5628b-9175-4ef3-8f39-41a97cb7749a","System behaviour in prestressed concrete T-beam bridges","Ensink, S.W.H. (TU Delft Concrete Structures)","Hendriks, M.A.N. (promotor); Lantsoght, E.O.L. (promotor); Delft University of Technology (degree granting institution)","2024","About 70 prestressed concrete T-beam bridges, constructed in the Netherlands between 1953–1977, are still in use today with many located in the main highway network. This type of bridge consists of prefabricated and prestressed T-shaped beams, with an integrated deck slab, cross-beams and transverse prestressing. Even if these bridges are well maintained, two important factors demand the current need for assessment: (1) increased traffic loading and (2) potential lack of shear resistance. Using traditional assessment methods it was concluded that about 50% of these bridges do not fulfil the current design code requirements. However, this does not automatically imply that these bridges are structurally unsafe, since some potentially significant additional load-transfer mechanisms are not taken into account in a traditional assessment. This is strengthened by the observation that, in general, these bridges do not show any signs of distress....","compressive membrane action; arching action; T-beam bridge; collapse test; assessment; Nonlinear Finite Element Analysis","en","doctoral thesis","","","","","","","","","","","Concrete Structures","","",""
"uuid:8570eb94-279e-4a3c-b662-b999fdac517c","http://resolver.tudelft.nl/uuid:8570eb94-279e-4a3c-b662-b999fdac517c","Reader-friendly Edible Binarycodes and Sensors Based on Smart Hydrogel","Zhang, M. (TU Delft Engineering Thermodynamics)","Mendes, E. (promotor); Eral, H.B. (copromotor); Delft University of Technology (degree granting institution)","2024","Food and medicines are two of the most essential categories of goods for human beings, providing vital nourishment and healthcare. However, as these products are commercialized and distributed on a global scale, consumers face the threat of counterfeit and deteriorated products. In response, this dissertation presents four prototypes consisting of On-Dose-Authentication (ODA) binarycodes and battery-less indicators based on smart hydrogel that are edible and reader-friendly to address these issues.
First, a microfluidic platform for continuous synthesis of hydrogel microparticles with superparamagnetic colloids (SPCs) embedded at prescribed positions has been established. The shape of the cross-linked microparticle is independently controlled by stop-flow lithography, whereas the position of trapped SPCs is dictated by virtual magnetic molds made of 2D nickel patches facilitating magnetic trapping. The spatial positions of trapped SPCs collectively function as a binary code matrix for product authentication. The proposed magnetic microparticles will contribute to the development of soft matter-inspired product quality control, tracking, and anti-counterfeiting technologies. (Chapter 2)
Second, a Physical Unclonable Functions (PUF) algorithm was developed to enhance the ODA binary codes' safety level. This algorithm exploits the diameter and coordinates of spheres as input, abandoning color and intensity as inputs, enabling imaging using common illumination and low-magnification microscopy hence lifting the reading constraints to advanced labs that are usually found in other current graphical PUF systems. Two sets of Poly(ethylene glycol) diacrylate ODA-PUF tags that can be read out via this algorithm were fabricated. The sets are single-diameter PUF leveraging random distributed superparamagnetic colloids of identical diameters and multiple-diameter PUF utilizing vortexed sunflower oil drops of various diameters, respectively. The performance of the single-diameter system was investigated. It passed NIST Statistical tests, demonstrating sufficient randomness, ideal bit uniformity, Hamming distance, and device uniqueness. The encoding capacity of the single-diameter system was found to be $9.2\times10^{18}$, which can satisfy labeling the annual output of Aspirin. (Chapter 3)
Third, a humidity indicator has been created that mechanically bends and rolls itself irreversibly upon exposure to high humidity conditions. The indicator is made of two food-grade polymer films with distinct ratios of a milk protein, casein, and a plasticizer, glycerol, that are physically attached to each other. Based on the thermogravimetric analysis and microstructural characterization, the bending mechanism is a result of hygroscopic swelling and consequent counter diffusion of water and glycerol. Guided by this mechanism, the rolling behavior, including response time and final curvature, can be tuned by the geometric dimensions of the indicator. As the proposed indicator is made of food-grade ingredients, it can be placed directly in contact with perishable products to report exposure to undesirable humidity inside the package, without the risk of contaminating the product or causing oral toxicity in case of accidental ingestion - features that commercial inedible electronic and chemo-chromatic sensors cannot provide presently. (Chapter 4)
Finally, an alginate TTI bead that encapsulates betacyanin, a natural colorant extracted from purple pitaya, is proposed to continuously monitor and reflect the temperature history of the perishable products to diagnose the storage conditions. The instability of betacyanin is exploited to demonstrate undesirable temperature abuse through visual color changes. The thermochromic change of the purple pitaya extract and the pitaya-extract-encapsulated bead was investigated under various temperatures, pH, and gaseous atmosphere conditions. Experimental results show that the proposed TTI exhibits an irreversible thermochromic change under a wide operation temperature range up to at least 100 \textdegree C with negligible disturbance from the gaseous composition. (Chapter 5)","Anti-counterfeiting; Binary code; Smart hydrogel; PUF; Humidity indicator; Time-temperature indicator","en","doctoral thesis","","978-94-6366-812-5","","","","","","","","","Engineering Thermodynamics","","",""
"uuid:81d05add-8bad-4589-98bc-9a68d86b0a8b","http://resolver.tudelft.nl/uuid:81d05add-8bad-4589-98bc-9a68d86b0a8b","Regional Allocation of Carbon Emissions for Road Freight Transport","Meijnema, Marc (TU Delft Technology, Policy and Management)","Annema, J.A. (mentor); Tavasszy, Lorant (graduation committee); Delft University of Technology (degree granting institution)","2024","Local governments hardly have a clear overview of their current progress in reducing emissions. This could be explained by the inadequacy of available tools. To address this issue, this research used a design cycle to explore the development of a feasible and useful method for allocating emissions in the road freight transport subsector. Four methods, two existing and two proposed, were evaluated against criteria derived from a literature review. A synthetic case study of Delft was conducted to evaluate these four methods and an indirect approach for relative accuracy, adaptability and feasibility. One of the proposed methods showed promise, but further research is needed to evaluate its absolute uncertainty. This proposed method is recommended to pursue, up until the moment the international standard only includes one method per subsector. Additionally, the proposed indirect allocation approach may offer greater flexibility when standards change and data is not fully accessible.","Emission Monitoring; Sustainability; Design Science Research; Case Study","en","master thesis","","","","","","","","","","","","Engineering and Policy Analysis","",""
"uuid:5c1b165c-4708-45fb-b12a-96b3f4f86f15","http://resolver.tudelft.nl/uuid:5c1b165c-4708-45fb-b12a-96b3f4f86f15","Supporting seat design for Smartphone use during travel","Udomboonyanupap, S. (TU Delft Applied Ergonomics and Design)","Vink, P. (promotor); Boess, S.U. (copromotor); Delft University of Technology (degree granting institution)","2024","This study investigates the impact of smartphone use on passengers' comfort during travel, focusing on train trips. The literature review reveals that smartphones have become the primary activity for train passengers, leading to discomfort and potential musculoskeletal issues, particularly in the neck, shoulders, arms, and back. The study aims to enhance the vehicle seat environment to alleviate these issues.
A questionnaire was administered to passengers, revealing that the main smartphone activities include listening to music, watching videos, reading, and texting. Most passengers prefer using smartphones with arm support, although a high discomfort score related to armrest use was noted. The study suggests exploring smartphone holders for watching videos and improving armrests for texting.
Passenger needs for the seating environment were collected through context mapping and co-creation techniques. Different age groups showed varied preferences in smartphone activities, with younger passengers and employees primarily using smartphones for entertainment, while older individuals engaged in diverse activities. The study emphasizes the importance of arm support, charging facilities, Wi-Fi, and considerations for special passenger groups like the disabled in future interior designs.
Chapters 5, 6, and 7 discuss design aspects to enhance smartphone comfort. An adjustable armrest is recommended, and experiments suggest an optimal trunk angle for smartphone use. A specially designed armrest reduced neck discomfort but increased discomfort in the upper arms, emphasizing the need for adjustable height. Chapter 8 provides specific recommendations for armrest height levels during various smartphone activities and proposes the use of smartphone holders.
In conclusion, the study suggests implementing adjustable armrests, smartphone holders, and considering the duration of smartphone use in future vehicle interior designs. These improvements aim to enhance body posture and reduce discomfort for passengers during smartphone usage. Further testing with end-users is recommended to validate these proposed solutions.","passengers; seat; comfort; design; smartphone use","en","doctoral thesis","","978-94-6366-811-8","","","","","","","","","Applied Ergonomics and Design","","",""
"uuid:29aa4d96-2365-44e9-9cf8-7e410529ee06","http://resolver.tudelft.nl/uuid:29aa4d96-2365-44e9-9cf8-7e410529ee06","Design of a Circular Product-Service System for 3D Printed Children's Footwear","Mac Donald, Kevin (TU Delft Industrial Design Engineering)","Magnier, L.B.M. (mentor); van Engelen, J.M.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","3D printing technology is a rapidly growing field in the context of footwear production, and in combination with computational design and foot scanning tools and algorithms, this allows for a shift from mass production to mass customization of footwear. This thesis considers the design of a new circular product-service system for children’s footwear, with the purpose of extending the benefits of mass customization to the target segment of children up to twelve years old, with their parents as key decision-makers in the footwear selection process. The development of this system also provides new insights for possible business opportunities for 3D printed footwear, and lays out opportunities and challenges around accelerating the shift towards a circular footwear industry.
A central aim of this thesis is to explore what constitutes a perfect fit for children’s footwear, how 3D printed footwear can be used to overcome challenges related to finding a perfect fit, and what retail experience and services need to be provided to create a system that removes barriers and promotes healthy foot development, considering this essential for healthy lifelong mobility. In this thesis, fit is constructed of three elements: physical, identity and social fit. The tensions and relations between these forms of fit are explored and translated into a concept design consisting of three parts: a physical product, an in-store experience, and a mobile service. Together, these deliver a system that aims to remove the need to compromise on aesthetic value or physical fit, put the child at the center of the footwear selection process, and inspire and facilitate more pro-active consumption behavior of children’s footwear. This project involved the creation of various physical and digital prototypes that were used to gain insights on key aspects of the proposed product-service system. Qualitative data resulting from exploratory customer research and user testing of the proposed concept, with parents as end-users, have resulted in a greater understanding of the technical and perceived challenges with regards to the implementation of such a new system for 3D printed children’s footwear.
In addition, this thesis oscillates between two equally critical perspectives: that of the user and that of the system. Technical and perceived tensions between personalized footwear and reuse of pre-owned footwear are revealed, and opportunities for take-back systems and end-of-life solutions are discussed. Furthermore, opportunities for rapid product improvement and more detailed analysis of foot and gait development are explored, as a result of the circularity of the system.
A strategy for market implementation of the proposed product-service system is detailed, highlighting the opportunity to create a system that onboards users of 3D printed footwear from the very first steps, and creating a membership and subscription based approach. Key strategic partners are identified for the realization of the proposed system, addressing complexities of the system, strategic positioning along the product and service supply chain and the need for expertise, specifically in the areas of production and fit measurement. Finally, this research highlights several key areas of interest and opportunities for future research and development.
It was found that PCwTD rarely come into contact with CwD and therefore lack the knowledge and skills to treat CwD properly and teach children with typical development (CwTD) about CwD. Additionally, mainly the differences between CwTD and CwD are perceived, preventing the normalisation of CwD.
Based on these findings, the design vision is formulated. The vision focuses on stimulating direct contact between CwD, PCwD, CwTD and PCwTD by guiding the parents to provide input for inclusive play. Followed by stimulating PCwD to help PCwTD correct the children during inclusive play and highlighting the similarities between the children.
Based on this vision, de Voelvlek is designed. The Voelvlek consists of a sensory rug, abstractly shaped balls called ‘monstertjes’ and play cards. The monstertjes are dynamic objects that stimulate spontaneous interaction between PCwD and PCwTD and stimulate bystanders to join the play. The parents can mix and match the play cards to facilitate inclusive play ideas for their children. By discussing the common interests of the children for the play, PCwTD learn about the similarities between CwD and CwTD. When the children are playing the PCwTD can continue this learning process through observation and the questions on the play cards. The play cards use different kinds of questions to stimulate parental interaction and help PCwTD reflect on their behaviour towards CwD and PCwTD.","Inclusive design; Parents of children with special needs; Barriers","en","master thesis","","","","","","","","","","","","Integrated Product Design | Medisign","",""
"uuid:0ff2a52c-cff1-41e3-889c-59c1bd6bb854","http://resolver.tudelft.nl/uuid:0ff2a52c-cff1-41e3-889c-59c1bd6bb854","Intent-Based CD&R: A Showcase and Evaluation of the Use of Intent in Orthogonal Constrained Urban Airspace","Liang, Jason (TU Delft Aerospace Engineering)","Ellerbroek, Joost (mentor); Hoekstra, J.M. (graduation committee); Sharpanskykh, Alexei (graduation committee); Badea, C. (graduation committee); Delft University of Technology (degree granting institution)","2024","The usage of drones in urban environments is expected to grow rapidly in the coming decades. To ensure the safe operations of drones, conflict detection and resolution are vital. Currently, a lot of research has gone into state-based CD&R, which has proven effective in unconstrained airspace but suffers from a large number of false positive conflicts in constrained airspace. The use of intent in constrained CD&R has the potential to reduce the number of false positive conflicts and improve the safety of drone operations significantly. In this paper, an intent-based detection and resolution method for orthogonal constrained very low-level urban airspace is presented and evaluated against a state-based method. The intent-based method calculates the future position along the trajectory at a time interval of 3 seconds for each aircraft, and conflicts are then detected by comparing these positions. The conflicts are solved utilizing a rule-based algorithm. The results show that the intent-based method has a much lower false positive rate for all traffic densities, as well as a higher average detection time before conflict for larger look-ahead times compared to the state-based method. The resolution of the state-based method, however, shows better performance with fewer losses of separation occurrences. With improvements, the intent-based method's low false positive rate, combined with the use of a larger look-ahead time, allows conflicts to be detected more reliably and earlier than the state-based method, thereby facilitating earlier conflict resolution and enhancing safety.","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:e4e7b731-8c79-45f4-98db-f827f2634d9f","http://resolver.tudelft.nl/uuid:e4e7b731-8c79-45f4-98db-f827f2634d9f","Physics based modelling of the impact of Unicom settings on the illumination pupils of EUV lithography machines","Klijnjan, Tim (TU Delft Electrical Engineering, Mathematics and Computer Science)","Budko, N.V. (mentor); Lahaye, D.J.P. (graduation committee); Tan, J. (mentor); Delft University of Technology (degree granting institution)","2024","Extreme Ultraviolet lithography is a vital step in the production of cutting edge computer chips that drive emergent technologies like AI, VR and the internet of things [1]. Careful control of Ultraviolet light beams by EUV machine modules such as the Unicom, Uniformity correction module, enable extremely precise printing of nano-scale structures on these chips. This thesis focuses on the construction of a model that predicts the impact of the Unicom on EUV illumination in ASML's lithography machines. Such a model could be used in a predictive maintenance scheme to prevent a fraction of unscheduled machine downtime, which can be estimated to cost ASML's customers around 38 million dollars per machine per year [2-4]. Similar problems have been tackled before [5, 6], but both existing models disregard multiple properties of the EUV machine and are incompatible with the type of measurements obtained by ASML. Therefore, the question remains how an accurate Unicom model can be constructed.
In this thesis, a physics based Unicom model was developed that can be fine-tuned to machine specific measurements. Significant reductions of up to 90.3% of prediction errors were obtained by using the model. Overall, making use of the model provided better or equivalent predictions when compared to not using the model for all but one of the investigated indicators of prediction quality. For the latter indicator errors remained within the desired bound, but further investigation is needed to discover why the Unicom model adversely affected this indicator. With an average execution time of 31.4 s, the created Unicom model in general enables swift and substantial accuracy gains.","EUV Lithography; Uniformity; Unicom; Illuminator; Illumination Pupil; Ray tracing","en","master thesis","","","","","","","","","","","","Applied Mathematics","",""
"uuid:5f21aff9-85e5-435e-8402-704263064e66","http://resolver.tudelft.nl/uuid:5f21aff9-85e5-435e-8402-704263064e66","Channel response of an engineered river to climate change and human intervention","Ylla Arbos, C. (TU Delft Rivers, Ports, Waterways and Dredging Engineering)","Blom, A. (promotor); Schielen, R.M.J. (copromotor); Delft University of Technology (degree granting institution)","2024","Humans have intervened in rivers for centuries. River engineering measures have aimed at protecting populations against flooding, ensuring reliable and safe navigation, providing freshwater for drinking, domestic and industrial use, irrigation, and energy supply, and providing opportunities for recreation. All around the world, measures such as channelization (i.e., channel narrowing and shortening), dam construction, or channel diversion have allowed for the proliferation of human settlements, technological progress, and an improved quality of life.
Despite the various socio-economic benefits of human intervention in rivers, engineering measures have side effects, often unaccounted for, or simply unknown before they manifest. This is because, by modifying the channel characteristics (geometry, planform, size of the bed surface sediment), or its controls (water discharge, sediment supply, base level), engineering measures alter the equilibrium state of a river. In response, rivers adjust toward the new equilibrium state through bed incision or aggradation, changes in channel width or sinuosity, or changes in the bed surface grain size distribution. This response may extend over hundreds of kilometers, and develop during decades to centuries....","rivers; channel adjustment; climate change; human intervention; Rhine","en","doctoral thesis","","978-94-6366-808-8","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:fdaf198a-8349-4790-a364-a1e4dc5a11b7","http://resolver.tudelft.nl/uuid:fdaf198a-8349-4790-a364-a1e4dc5a11b7","Design and Analysis of Macro-Economic Models in the Laplace Domain: An Economic-Engineering Approach","van Rijen, Gijs (TU Delft Mechanical, Maritime and Materials Engineering)","Mendel, M.B. (mentor); Hutters, C. (graduation committee); Delft University of Technology (degree granting institution)","2024","In this thesis, we demonstrate the efficiency of Laplace domain techniques for the design and analysis of economic systems. To make the techniques applicable to economic modeling, we establish the economic analogs to the various tools and nomenclature in the engineering literature. We show that the Laplace domain provides an alternative description of economic systems, offering insights into behavior not apparent in the time domain. This allows economic discounting and cycles to be efficiently analyzed using pole-zero maps, Bode plots, and similar techniques. In addition, we demonstrate that transforming the linear differential equations of economic engineering into algebraic equations in the Laplace domain simplifies the design of economic systems.
We use the Laplace domain techniques to design and analyze a macroeconomic model. By designing the model in the Laplace domain, we are able to integrate supply chain dynamics and the housing market using two-port network theory.
By analyzing the model using a pole-zero map, we show that the economy's discount rates and business cycles are represented by complex poles and the economy's transmission blocking rates by complex zeros. Additionally, we demonstrate that the Bullwhip effect, a supply chain phenomenon, can be intuitively visualized using a Bode plot. These applications illustrate how Laplace-domain techniques enable the efficient design and analysis of economic systems.","Laplace Transforms; Macroeconomics; Economic Engineering","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:ef90d088-f7ac-4767-a926-3b4bac9497e9","http://resolver.tudelft.nl/uuid:ef90d088-f7ac-4767-a926-3b4bac9497e9","Alkaliphilic Life: Adaptation strategies by Caldalkalibacillus thermarum","de Jong, S.I. (TU Delft BT/Environmental Biotechnology)","van Loosdrecht, Mark C.M. (promotor); McMillan, D.G.G. (copromotor); Delft University of Technology (degree granting institution)","2024","Alkaliphiles thrive in environments with a pH of 8.5 or above, while maintaining an internal pH closer to neutral. Thus, alkaliphilic microorganisms have a proton gradient inverted with respect to the normal orientation. Intuitively, this would nullify the potential to generate energy via respiration with regularly oriented respiratory chains that rely on proton-coupled ATP synthases. Yet, alkaliphilic respiratory chains are oriented traditionally and are actively used. The question therefore is how they are able to create conditions conducive to such behaviour. In addition, attempts to answer that question will hopefully also clarify how alkaliphiles acidify their cytoplasm with respect to the exterior milieu in the first place. This thesis details methods required to study these questions and provides some answers regarding alkaliphilic life. This thesis focuses on a single category of alkaliphiles: the low-salt gram positive alkaliphiles. These microbes have just a single membrane, the proteins therein, and a cell wall to generate conditions suitable for energy generation and other transport mechanisms. In short, it can be regarded as the most basic system to study an alkaline, or basic, problem....","Alkaliphile; Membrane; Genomics; Proteomics; Lipidomics","en","doctoral thesis","","978-94-6361-963-9","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:40e897ce-b9d3-40fb-b615-b6768a7fc031","http://resolver.tudelft.nl/uuid:40e897ce-b9d3-40fb-b615-b6768a7fc031","Towards More Meaningful And Superior Digital Experiences in Luxury Automotive: A roadmap for the introduction of a blockchain technology ecosystem considering the needs of evolving customers","Calamita, Kyria (TU Delft Industrial Design Engineering)","Bakker-Wu, S. (mentor); Secomandi, Fernando (graduation committee); Delft University of Technology (degree granting institution)","2024","The accelerated digitalization of daily interactions, significantly influenced by the Covid-19 pandemic, has rendered the digital realm a fundamental aspect of life across generations. This shift has led to a transformation in digital asset management, ownership, and trade. The introduction of blockchain technology, especially non-fungible tokens (NFTs), has initiated a new era where digital items are capable of scarcity and uniqueness—attributes previously exclusive to physical luxury goods.
In this light, the project investigates the convergence of blokchain technology with the luxury automotive sector, seeking to unlock the business potential for luxury Original Equipment Manufacturers (OEMs).
Through creative trend research, emerging trends and developments have been identified, delineating the future landscape of luxury automotive. A strategic vision for luxury OEMs has been formulated, establishing a reference point for innovation and customer-centric product development.
The project has pinpointed four products, each embodying the promise to resonate with the evolving values of luxury consumers and to propel business growth. These products are central to a structured roadmap, which is segmented into three strategic horizons, guiding towards the envisioned future. Each horizon encompasses specific goals, in harmony with the progression and integration of these digital products.
The roadmap produced is a detailed blueprint for luxury automotive companies to contemplate the integration of blockchain technology with luxury experiences. The report concludes with an evaluation of the products and the roadmap by luxury automotive professionals, and suggestions for further research to
refine the strategic approach. This comprehensive evaluation encapsulates the project’s full scope and its approach to aid luxury automotive towards more meaningful and superior digital experiences.","Design Roadmapping; Luxury Automotive; NFT; Blockchain","en","master thesis","","","","","","","","","","","","Strategic Product Design","",""
"uuid:dc619f49-fd64-4186-a45c-8b97a7c9459d","http://resolver.tudelft.nl/uuid:dc619f49-fd64-4186-a45c-8b97a7c9459d","Assessing the Efficacy of Deep Learning Models in the Context of Active Flow Control","Sara Boby, Sara (TU Delft Mechanical, Maritime and Materials Engineering)","Della Santina, Cosimo (mentor); Laskari, A. (mentor); Delft University of Technology (degree granting institution)","2024","In the field of fluid mechanics, there has been a significant shift towards the integration of machine and deep learning techniques to address challenges in reduced-order modeling, flow feature analysis, and control, especially within the realm of active flow control (AFC) for objectives such as lift optimization and drag reduction. Deep learning has taken a central role in advancing state-of-the-art AFC methods by creating data-driven models that mitigate the computational demands of conventional Computational Fluid Dynamics (CFD) simulations, enabling real-time fluid control. Despite the predominance of models trained offline and focused on simple scenarios like laminar flow around bluff bodies, the utility of sophisticated learning methods in AFC has remained largely unexplored.
This research introduces a novel benchmark in fluid dynamics—a soft robotic tentacle actuator—to evaluate the effectiveness of deep learning architectures in complex flow control situations. Through the comparison of online and offline learning frameworks for predicting system behavior, the study elucidates the strengths and limitations of deep learning networks in AFC. The findings underscore the constraints faced by deep learning architectures when dealing with aperiodic motions and demonstrate the significant benefits of adopting an online learning approach over offline training methods, thereby highlighting the advantages of adaptive learning strategies in complex AFC scenarios. The online learning framework displays more stability and increased quality of forecasts at larger time horizons.","Online Learning; Active flow control; Data driven nonlinear system forecasting","en","master thesis","","","","","","https://github.com/sboby/FNN_Offline Git hub repo of the thesis","","","","","","Mechanical Engineering","",""
"uuid:9ae79525-c403-4cc0-9b71-662db3db9516","http://resolver.tudelft.nl/uuid:9ae79525-c403-4cc0-9b71-662db3db9516","Hybrid Phaco: Driving circularity in eye surgery with a semi-disposable phacoemulsification redesign","Timmerman, Lars (TU Delft Industrial Design Engineering)","Diehl, J.C. (mentor); Persaud, S.M. (graduation committee); Vervaet, Joost (graduation committee); Gähler, Mart (graduation committee); Delft University of Technology (degree granting institution)","2024","Cataract surgeries using phacoemulsification (phaco) are standard practice, accounting for the large majority of all cataract surgeries. Reliance on sterilization processes has significant environmental implications, giving its energy and resource intensive nature.
This thesis introduces a novel hybrid phaco handpiece design, eliminating the need for sterilization by adding a disposable to facilitate sterile use, combined with a reusable as driver of ultrasound. This product is the first step towards a proposed fully circular system. This project has a focus on reducing impact, while maintaining phaco functionality; it does so by testing for phaco ultrasound characteristics and functioning fluidics while addressing the challenges associated with sterilization. The design emphasizes quick, secure, and sterile assembly in the operating room (OR) while maintaining cost-effectiveness and minimizing environmental impact.
The hybrid phaco handpiece achieves its functional design by carefully managing the components responsible for ultrasound and fluidics. The internal sonotrode, driving ultrasound, is split between the disposable and reusable components, connected securely through a threaded interface. Fluidics are managed by splitting off before reaching the reusable part, employing a simple yet effective O-ring design in the disposable product.
Maintaining sterility in the OR is a critical aspect of the hybrid phaco handpiece design. Mechanical seals in O-rings provide internal sterile barriers, and a blister pack facilitates sterile interaction between non-sterile and sterile components. The contact-free assembly of the disposable into the reusable ensures a tight connection, validated by a torque ridge that breaks at a specified torque, offering a visual cue for successful connection. This usability design, validated with healthcare professionals, adds safety and fits the quick nature of cataract procedures.
The innovative sterile handover method is implemented through the packaging itself, acting as a sterile barrier between different nurses handling the disposable and reusable components. During handover, a pre-attached sterile tube sleeve is unrolled over the non-sterile component. This ensures a seamless and sterile transition during assembly, minimizing the risk of contamination.
A comprehensive functional analysis validates the hybrid design, ensuring it meets specifications. Insights gained from this analysis guide further mechanical tuning, particularly in aspects influencing ultrasound characteristics. Beyond functionality, the hybrid phaco handpiece design has environmental implications. By eliminating the need for energy-intensive sterilization procedures and reducing waste from disposable wraps, the design reduces its climate impact by 67% over the entire life cycle.
This hybrid phaco handpiece design represents a step towards a circular system in the field of cataract surgeries. Balancing functionality, sterility, and environmental impact, this novel approach not only provides new insight into sustainable phacoemulsification procedures, but also shows the potential of hybrid reusable and disposable products in healthcare.
The city is designed to be human-centred. In the multispecies urban environment humans take on roles of management and ownership over flora and fauna. This leaves the richness and biodiversity of urban habitats in the hands of humans (Denters, 2020). Ecology is often treated as a second class citizen and given opportunities according to human preferences.
In collaboration with material-centred design agency Refunc, this project explores the way designers can work with the entanglements around local ecology and facilitate equal and just treatment of ecology as an added client of otherwise human-centred design.
More-than-human perspective
In the first stage of the project, practices from more-than-human-design theory, Refunc, nature-inclusive building and ecologists are collected and urban human-ecology relations are explored by noticing entanglements (Tsing, 2021) and multidisciplinary collaboration. To allow more opportunities for ecology to be revitalised in urban environments the main objectives are to create space and facilitate agency for ecology.
Decentring through experimentation
In the following stage of the project
designing, making and co-creation are used as knowledge generation tools. Through multiple design experiments the application of more-than-human design and Refunc’s practices is explored and more practices are collected and defined.
The main challenges of adopting the more-than-human perspective are:
The lack of knowledge and understanding of ecology and the complexity of entanglements.
Decentering the human in the design process.
Play and multidisciplinary collaboration can support the designer in finding new multispecies uses for objects.
Added to Refunc’s framework are lively materials, nonhuman functions and more-than-human clients. As well as a change in perspective from projects that are finished once they are produced to interventions that are ever changing.
A (never) complete journal of practices for designers of urban ecology
A journal is created to provide support to beginning more-than-human designers.
The design goal is to introduce them to MTHD practices and inspire them to experiment in a project with urban ecology.
The journal is filled with 29 practices, examples of interventions and activating questions. It is a collection of the work of this project and a starting point for another designer going on a similar journey. They are recommended to be applied and explored one by one in a reflective and iterative design process. After the designer has mastered its contents, the journal can be planted and create space for ecology by itself.
Lastly, the journal and this project are an invitation to every designer to experiment and explore how their projects can involve more-than-human ecology.
Focussing on mechanical vapour compression heat pumps, a thorough understanding of such cycles is gained first. The performance of a heat pump is highly dependent on the choice of cycle setup and working fluid, with the compressor posing the largest limitations for higher temperatures. To assess these, this project develops a heat pump model which simulates many different working fluids for different component configurations. The model was subjected to two temperature domains, covering waste heats of 100 ◦C & 200 ◦C and process heat temperatures in the range of 150 ◦C to 400 ◦C.
Results were obtained for all fluids incorporated in RefProp 9.0 and showed that multistage compression with intercooling and superheating considerably improved the performance of nearly all fluids. By comparing fluids based on efficiencies, capacities, temperatures and pressures, benzene and propylcyclohexane showed the best performance for the lower and higher part of process heat temperatures, respectively. The results however also showed the potential superiority of water as it has the best efficiencies and the largest applicability range, which combines with the hazard-free & environmentally friendly nature, low cost and wide availability. The main downside of water appeared to be the persistent, unacceptably high compression temperatures, combined with large pressures and pressure ratios. It was subsequently investigated how the disadvantages of water could be handled. A solution was found in the usage of Liquid Piston Gas Compression (LPGC), in which a rising liquid column, supplied by a pump, acts as a reciprocating piston in a compression chamber. This setup conveniently allows for liquid spray injection to cool the steam upon compression and alleviates limitations on the pressure ratio. By using the same water as the liquid in the LPGC, any temperature rise is compensated by the evaporation of liquid, resulting in more steam with a lower temperature. A numerical model of this type of compressor was made in which dynamics were modelled down to individual droplets. This simplified approach provided insight into the compression path with such liquid injection and allowed the approximate determination of the required amount of spray. Results showed that the injection could cool the vapour adequately even for high temperature lifts. The LPGC was subsequently incorporated into a single-stage heat pump cycle and compared the results for other fluids using ordinary compressors. These results showed large CoP improvements of 15-25 % CoP and low discharge temperature. With that, it was shown that an environmentally friendly fluid could be used in a simple single-stage configuration and still provide the best performance compared to any other fluid.","High-temperature heat pumps; liquid piston gas compression; Vapor compression heat pump; water; Intercooling; Superheating","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Energy, Flow and Process Technology","",""
"uuid:5a44e49e-6df3-469b-b9a6-f19085188280","http://resolver.tudelft.nl/uuid:5a44e49e-6df3-469b-b9a6-f19085188280","Drivers’ Behaviour on Freeway Curve Approach: Different Angles, Different Perspectives","Vos, J. (TU Delft Transport and Planning)","Hagenzieker, Marjan (promotor); Farah, H. (promotor); Delft University of Technology (degree granting institution)","2024","This dissertation explores what road characteristics trigger drivers’ speed adjustments when approaching freeway curves. It combines speed prediction modelling and human factors research methods. The results show that drivers primarily consider visible cues such as the preceding roadway, deflection angle, and the number of lanes, as opposed to traditional factors like horizontal radius or speed signs, when starting to decelerate. The study advocates for integrating driver perspectives into road design.","Geometric freeway design; human factors; Curve driving","en","doctoral thesis","","978-90-5584-340-4","","","","","","","","","Transport and Planning","","",""
"uuid:a26f9d02-74db-4f87-b99b-5b226065c598","http://resolver.tudelft.nl/uuid:a26f9d02-74db-4f87-b99b-5b226065c598","Applications of Dynamic Covalent Bonds in Chemical Reaction Networks","Spitzbarth, B. (TU Delft ChemE/Advanced Soft Matter)","Eelkema, R. (promotor); van Esch, J.H. (promotor); Delft University of Technology (degree granting institution)","2024","Nature has inspired countless researchers in their quest to understand the phenomena we observe and utilise their findings to develop new technologies. This becomes especially apparent in systems chemistry, which heavily draws inspiration from natural systems in its pursuit for the understanding and development of chemical reaction networks (CRNs) with interesting properties. Today, CRNs play a big role in many sensors, amplification systems, transient materials, and more. Despite major advances in the field of CRNs, there is still a need for additional robust, versatile chemistries to allow for more diverse applications, both within systems chemistry and in other fields beyond, such as material science. This thesis aims to explore new applications of Dynamic Covalent Chemistry (DCvC)—typically utilised to make self-healing materials—in CRNs to allow for new applications drawing from the versatile chemistry used in DCv systems.","Chemistry; dynamic covalent chemistry; Catalysis; Self-healing material; Chemical reaction network","en","doctoral thesis","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:2f3c84ef-5d97-41dd-82f4-c69855246a29","http://resolver.tudelft.nl/uuid:2f3c84ef-5d97-41dd-82f4-c69855246a29","Routing based on User Requirements","Bestebreur, Timon (TU Delft Electrical Engineering, Mathematics and Computer Science)","Kuipers, F.A. (mentor); Pouwelse, J.A. (graduation committee); Zapletal, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","The versatility of the internet enables many applications that play an increasingly bigger role in our society. However, users have little control over the route that their internet traffic takes, which prevents them from controlling who sees their packets and how their traffic is handled. Researchers have proposed an extension to the internet, called the responsible internet, that aims to provide users with control over the route that their internet traffic takes.
Providing this control is the aim of this thesis. Users can control their route by specifying requirements that their route has to fulfill. This thesis defines the Maximum Path Requirement Intersection (MPRI) problem as the problem of finding the route that satisfies as many of the user’s requirements as possible, and this thesis proves that MPRI is NP-hard. Subsequently, both a heuristic to solve the problem in a reasonable amount of time as well as an exact algorithm that guarantees to find the globally best path are introduced. The performance of the heuristic is measured relative to the globally optimal solution given by the exact algorithm. Results show that less features allow the heuristic to have a larger search space, which improves the results; that the runtime of the heuristic scales polynomially in the number of hops between the start and end node; that the heuristic is most effective in graphs that have a power-law degree distribution and least effective in grid-like graphs; and that in a realistic setting the heuristic runs quickly while performing close to optimal.","Internet; internet routing; Pathfinding; BGP; autonomous systems; Controllability; privacy; Security; Usability; maximum set intersection; Requirements","en","master thesis","","","","","","","","","","","","Electrical Engineering | Embedded Systems","",""
"uuid:8e38a609-bf24-48ec-9a9f-24fc294c0be1","http://resolver.tudelft.nl/uuid:8e38a609-bf24-48ec-9a9f-24fc294c0be1","Redesign of the Artechno vertical farm robot: Herontwerp van de Artechno vertical farm robot","Colsen, Quincy (TU Delft Mechanical, Maritime and Materials Engineering)","Schott, D.L. (graduation committee); van den Bos, W. (mentor); Delft University of Technology (degree granting institution)","2024","This thesis focuses on a vertical farming system designed for growing crops. The system’s deficiencies were identified during a company visit where the system was operating. An analysis was conducted to see when all deficiencies would be resolved. It revealed that the vertical farm robot had to be redesigned to grab seven benches deep to eliminate the system’s shortcomings and significantly enhance its performance. Thus, a literature review was conducted to determine possible solutions. As a result, various alternatives were devised based on the requirements and constraints considering the available design space and a morphological chart. These alternatives were scored with a weighted criteria method, and the best view was elaborated in more detail. Subsequently, a computer-aided design of the best overall-looking design was created. After ordering all materials, a design prototype was built inside a climate cell in the research centre, and all sensors and drives were wired and controlled by a programmable logic controller to fully automate the prototype. A proof of concept was successfully obtained from the test results. Therefore, this redesign of the system’s performance was enhanced, and this thesis was successful.","Redesign; Vertical Farming; Robotics; Engineering; design approach; Artechno growsystems","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Multi-Machine Engineering","","52.0060928, 4.3450368"
"uuid:76d318c1-9eb4-460f-9619-56f25abb9970","http://resolver.tudelft.nl/uuid:76d318c1-9eb4-460f-9619-56f25abb9970","Dutch Housing Commons: Non-speculative housing within and against the housing market","Vork, Sebastiaan (TU Delft Architecture and the Built Environment)","de Haas, M.J. (mentor); Gosseye, J. (mentor); van den Ban, R.R. (mentor); Visscher, H.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","The Netherlands is facing a housing shortage and adequate housing provision is lacking. Citizens are eager to act on their own through bottom-up initiatives. However, bottom-up initiatives (such as cooperative housing) do not thrive within the current housing market and therefore significant development of cooperative housing in the Netherlands stays off. This research aims to support the development of cooperative housing in the Netherlands. This is being achieved through constructing an alternative reality of the housing market through composing a play script. The script is being informed by interviews, literature review and analysing case study projects. The interviews were conducted among the present stakeholders (the academic, the advocate, the architect, the bank, the cooperative, the developer, the dweller, the municipality). All together, the research hopes to transfer these thoughts and findings on cooperative housing to continue this collective process.","Cooperative housing; Ficto-criticism; Transformation; Post-65 architecture; Bandstad; Spatial Agency","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Explorelab","","51.84507707905844, 5.854913296000472"
"uuid:9053ca77-cb4d-4da5-8b97-c29832167743","http://resolver.tudelft.nl/uuid:9053ca77-cb4d-4da5-8b97-c29832167743","Autonomous assembly of digital materials: with inchworm locomotion robotic assemblers","Presa Magriña, Guille (TU Delft Aerospace Engineering)","Masania, K. (mentor); Delft University of Technology (degree granting institution)","2024","Throughout history, human progress has been defined by the mastery of materials, transitioning from stone and bronze to the steel age. However, this progression has not only been defined by the materials utilized but has also encompassed a shift in processes, moving from the industrial to the information era. Despite the advances in fabrication techniques, building large and detailed structures continues to pose an unresolved challenge. Cost, speed, performance and size are often mutually exclusive objectives that are bound by the materials and processes used.
In the search for new processes and materials, we can find inspiration in the oldest of all fabricators; life. In natural systems, a small set of 20 amino acids are assembled by ribosomes into coherent organisms with complex sensing, actuation and information storage. Nature represents the highest dynamic range assembly system known to mankind. But a question arises: can these benefits be extended to engineering systems at meso and macro scales?
The advantages of natural fabrication emanate from the use of digital materials and self-replicating assemblers. Digital materials are composed of precise and discrete building blocks like amino acids at the micro-scale or Lego building blocks at the meso scale. They are tolerant to noise, possess embedded metrology and their assembly can be highly parallelized. Lego structures can be built more repeatably than what a standard 3D printer can print despite the imprecise nature of human assemblers. This is because the metrology and the code for construction are embedded within the material itself.
In this thesis, a complete end-to-end autonomous digital material assembly system, that bridges the gap between a 3D model and a built structure with a flexible, comprehensive, and easy-to-use toolset is presented. All elements in the triad of autonomous digital assembly were developed, from the digital material to the robot and the controlling software. A digital material made of discrete 3D-printed octahedra lattices that can be magnetically or mechanically joined is utilized. Straight, curved and elongated lattices enable unparalleled geometric freedom.
This material can be picked up, transported and placed by a robotic assembler in the form of a 5DOF (degrees of freedom) cable-driven differential joint inchworm robot.
Most importantly, a flexible control platform capable of interpreting 3D models, developing the necessary robot movements for optimal construction and wirelessly controlling assembler robots powers the build process. This platform introduces some major innovations within the field. For starters, it is not limited to blocky grid domains as it is powered by inverse kinematics. It is also architected to enable cooperation between different assembler types by utilizing a work package system and presents wide abstraction layers allowing further development at higher levels with ease. Additionally, it provides a seamless control interface.","Robotic Assembly; Robotic Building; robotic locomotion; Additive Manufacturing; Planning and control; Path Finding; Pathfinding; Inverse Kinematics; Collision detection; Collision avoidance; Cable driven parallel robot; 3D printing","en","master thesis","","","","","","","","2025-02-28","","","","Aerospace Engineering","",""
"uuid:06bf2239-db11-41ee-bab2-a90e95b3ceb8","http://resolver.tudelft.nl/uuid:06bf2239-db11-41ee-bab2-a90e95b3ceb8","Sensor Fusion for Visual-Inertial Simultaneous Localisation and Mapping: Applied and tested on a small ground-based mini rover","Bekkers, Sam (TU Delft Mechanical, Maritime and Materials Engineering)","Della Santina, C. (mentor); Delft University of Technology (degree granting institution)","2024","The generation of a 3D map of an unseen environment, obtained through solving the SLAM problem, is a popular topic currently in the robotics domain. The Lunar Rover Mini (LRM) at the German Aerospace Center solves this problem using a RGB-D camera system, which is favourable in space applications due to its lightweight characteristics and energy-efficiency. Performing SLAM based on camera images is based on visual odometry: the science of estimating the rover’s trajectory trough a sequence of images. However, the dependency on a
single sensor to perform mapping and navigation poses a threat to the reliability of the system. To increase the reliability and robustness of the SLAM algorithm, an inertial measurement unit (IMU) is incorporated in the robot hardware.
This thesis describes the design for a visual-inertial SLAM algorithm that incorporates both visual and inertial measurements to solve the SLAM problem through performing tightly coupled sensor fusion, which estimates and corrects for IMU biases. The solution is based on a non-linear factor graph, which is a graphical model to represent the relationships between the
rover’s measurements and the unknown variables which are optimised for. This is done using the open-source GTSAM framework. Using experimental data, the robustness of the novel visual-inertial SLAM algorithm is demonstrated by simulating specific sensor failures. Moreover, the novel algorithm shows its capability to incorporate a degree of certainty regarding specific areas of the generated map, closely resembling how a human being would generate a
map of an unknown area.
An additional use case for tightly coupled sensor fusion is the increased accuracy of the estimated trajectory. Assuming Gaussian noise models for both measurement models, averaging the two can yield a higher accuracy than either of the two sensors could have obtained by itself. This hypothesis was tested in another experiment. As the main mechanism behind bias estimation is reducing the error between visual and inertial measurements, bias estimation is quickly affected by this drifting visual odometry, which in its turn deteriorates the accuracy of the visual-inertial odometry module. This observation proves that the bias estimation is not correlated to the underlying physical process, but is rather just a numerical value in the optimisation reducing the residual error. It raises the question whether this strategy of tightly coupled sensor fusion can actually be used to increase the accuracy of a visual odometry algorithm.","SLAM; Sensor Fusion; Stereo camera; IMU; Bias estimation","en","master thesis","","","","","","This thesis was conducted in close collaboration with the German Aerospace Center in Oberpfaffenhofen, Germany","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:e202a1f3-9c73-42d1-b7f6-d45f9631df74","http://resolver.tudelft.nl/uuid:e202a1f3-9c73-42d1-b7f6-d45f9631df74","Data assimilation in a LOTOS-EUROS chemical transport model for Colombia using satellite measurements","Yarce Botero, A. (TU Delft Atmospheric Remote Sensing)","Heemink, A.W. (promotor); Quintero Montoya, O.L. (promotor); Delft University of Technology (degree granting institution)","2024","When considering air quality, notably in South America, it seems that we are falling behind more developed regions in exacerbating the issue. This shortfall serves not just as observation, but as a warning, as air quality problems here are rapidly escalating. Nevertheless, by examining how other countries have addressed similar issues, we can prepare ourselves to tackle our own challenges. In this thesis we demonstrate how utilizing Data Assimilation DA we can reduce the uncertainty in some model uncertain parameters in an air quality model such as the LOTOS-EUROS Chemical Transport Model (CTM).....","Data Assimilation; Chemical Transport Model; Ensemble-based methods; Satellite data assimilation; Low-cost in situ measurements","en","doctoral thesis","","978-90-834024-2-0","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:cce7f942-5bc7-4438-b910-3c32864eb6f7","http://resolver.tudelft.nl/uuid:cce7f942-5bc7-4438-b910-3c32864eb6f7","Applying Mixed-Integer Quadratically Constrained Programming to Reduce Fuel Cell Degradation Onboard a Hybrid Ship","Degeling, Pieter (TU Delft Mechanical, Maritime and Materials Engineering)","van Biert, L. (mentor); Coraddu, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","New methods of ship propulsion are required to meet the targets for reducing global emissions of greenhouse gases. Hydrogen-powered fuel cells can be used to greatly reduce emissions, facilitating renewable shipping. Fuel cell durability is recognised as a large barrier to widespread fuel cell application. The goal of this graduation project is to develop a model which can be used to examine the trade-off between hydrogen consumption and degradation in the operation of a fuel cell/battery hybrid ship. The main research question is defined as follows:
”How does incorporating fuel cell degradation in the energy management system of a hybrid marine propulsion system affect the resulting fuel consumption and degradation?”
An optimisation approach is used to develop an energy management system. A quadratic mathematical model is constructed using the fuel cell’s polarisation curve as its basis. Linear relations for a fuel cell’s current-voltage relation are used to describe the fuel cell power as a quadratic current-power relation. Fuel cell degradation is included in the model by defining various operating conditions and relating them to degradation rates reported in the literature. In turn, the degradation influences the polarisation curve, thereby limiting the fuel cell’s performance. This quadratic approach to modelling the interplay between fuel cell degradation and the fuel cell’s performance is the main contribution to the literature.
The proposed energy management system is used to determine a vessel’s optimal operation, depending on the objective function applied. Two objectives are defined: minimisation of fuel consumption and minimisation of fuel cell degradation. Besides testing these single objectives, a weighted-sum approach to multi-objective optimisation is carried out using hydrogen and fuel cell system costs.
The optimal operation of the vessel is analysed based on key performance indicators such as fuel consumption, fuel cell degradation and operating costs. Incorporating fuel cell degradation in the energy management system leads to a reduction in degradation of up to 33% for the long-term simulation of the case study applied in this thesis when compared to the results for the minimisation of fuel consumption. A large increase (50%) in fuel cell lifetime can be accomplished with a very limited increase in hydrogen consumption (0.5%).
This research contributes an intuitive modelling method for the interplay between fuel cell degradation and the fuel cell’s performance. It provides insight into the considerations between fuel cell degradation and hydrogen consumption while operating a hybrid vessel, addressing a small part of a technical solution to mitigating emissions.
One promising solution involves re-utilising the city's waterways and employing vessels to transport waste out of the city. Two pilots involving water-based waste transport have been conducted in the city and were found to be a working proof of concept. It is, however, not known what a water-based collection system for the whole centre should look like to service the city and preserve the quays and bridges. This thesis aims to assess the trade-offs between three conceptual water-based waste collection systems (WCSs) to guide the direction for designing a suitable WCS for the city.
The three concepts examined concepts differ in the scale of the transshipment locations (the point where waste is transferred from land to water), categorised as WCSs with small- medium- and large-scale transshipment locations. The study focuses on the trade-offs between WCSs within and between the domains of social acceptance and technical feasibility.
This thesis consists of two main parts, in the first part the three water-based conceptual WCSs were defined using a design workshop. During the workshop, six employees of the municipality used different exercises to generate ideas on how waste could be collected using the waterways and to turn these ideas into conceptual designs.
In the second part of this thesis, these three conceptual WCSs were studied using a case study. The units of analysis in each of the WCSs were the social acceptance and the technical feasibility.
To evaluate the technical feasibility of each of the WCSs, expert interviews with specialists in vessels, waterways, quay walls and assets were conducted. The social acceptance of the three WCSs was studied using a survey administered to potential users of these systems. They were asked to choose between various WCSs based on walking distance, their general preferences, their preferences in specific situations and their concerns regarding these systems. Parallel to the survey, potential user interviews were conducted to gain deeper insights into respondents' reasons for preferences or aversions to specific WCSs.
The results from the expert interviews were summarised and presented in a table to provide an overview of the feasibility of the three WCSs. Survey results were depicted through graphs illustrating respondents' choices, while potential user interviews were analysed thematically, supported by quotes from the interviews.
WCS with large- and medium-scale transshipment locations were both found to be potentially feasible from a technical perspective, whereas the small-scale option was deemed unlikely to be feasible. The survey indicated that the majority of the respondents had a preference for self-disposal in containers close to their homes as opposed to having their waste collected at a self-scheduled time, requiring them to be present at home to hand over the waste to the pickup service. Additionally, respondents preferred disposal facilities not too close to their homes or within their direct line of sight.
Insights from potential user interviews revealed that participants favouring self-disposal valued flexibility, while on the other hand, those preferring self-scheduled pick-up appointments believed this WCS would address the litter issue in the city.
In conclusion, a key trade-off identified was between providing residents with their most preferred waste disposal method through numerous disposal locations versus the technical challenges, if not impossibility, of realizing such a large number of locations.
Based on this, the municipality was recommended to conduct further research on WCSs with large- and medium-scale transshipment locations, alongside implementing pilot projects to test these systems in a real-world setting.","Waste collection; Amsterdam; Trade-offs","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","","52.377956, 4.897070"
"uuid:79c6bd6b-d008-408b-a2ac-aef988df76e2","http://resolver.tudelft.nl/uuid:79c6bd6b-d008-408b-a2ac-aef988df76e2","Safely Building New Houses in the Geul Catchment: How to mitigate the impact on flooding?","Idsinga, Daan (TU Delft Civil Engineering & Geosciences)","Hut, R.W. (mentor); De Weerd, Mark (mentor); Hrachowitz, M. (graduation committee); Buitink, Joost (graduation committee); Hutten, Rinske (graduation committee); Delft University of Technology (degree granting institution)","2024","In July 2021 severe flooding occurred in the South of Limburg, Belgium, and Germany due to heavy precipitation. Extreme precipitation events like this are expected to occur more often in our changing climate. Urbanization is thought to be another contributing factor to the July 2021 flood event. The Netherlands is expected to increase urbanization as a solution to its housing shortage. To make room for urbanization, while minimizing the effect of climate change, the government wants to make ”water and soil leading”, Water en Bodem Sturend, in the decision-making about the layout of the Netherlands.
Therefore, the goal of this research is to investigate the best suitable subcatchment for the construction of new residential houses within the Geul catchment, in terms of flooding. The July 2021 flood event is used as a reference. The first step was to investigate the hydrological response of the Geul catchment. Secondly, this hydrological response was modelled by the semi-distributed hydrological models HBV coupled to D-RR and by the distributed model Wflow_sbm. HBV and D-RR are set up in this research, while Wflow_sbm is adopted from Klein (2022) and Bouaziz (2022). The hydrological models are coupled to the Geul hydrodynamic model D-HYDRO of Hulsman, Weijers, Verstegen, and Goedbloed (2023). The building plans in the Geul catchment were investigated and scenarios were constructed. These scenarios were simulated in the hydrological models. This method resulted in a workflow that can be found in Idsinga (2024). The workflow can be applied on analyses of different land cover types.
The modelled hydrographs showed differences between the hydrological models. Each model better describes one part of the hydrological response compared to the other. HBV and D-RR better represent the subsurface flow and describe the hydrological response during consecutive precipitation events. Wflow_sbm represents the overland flow flux better and therefore describes the hydrological response during the July 2021 flood event. The modelled flood extents during the July 2021 flood event are also compared to the estimated extent by Slager, de Moel, and de Jong (2021). Wflow_sbm showed better similarity to the measured flood extent than HBV and D-RR. The Province of Limburg wants to build 18,730 new houses in the South of Limburg. This results in an increase of 6 km2 paved area. In this research, this increase is applied to different locations in the Geul catchment. Next, the impact of completely paved subcatchments was investigated. The relatively small 6 km2 increase in paved area did not result in different discharge behaviour and the total area of the flood extent showed a small difference. However, it impacted the flooded paved area. Building far from the river on the hills resulted in no increase in the flooded paved area. New houses in the valleys, close to the river, are more exposed to flooding. In the Meerssen subcatchment, the added paved area was responsible for 95% of the total increase in the flooded paved area. This was also the case in the Gulp subcatchment, where about 90% of the increase in flooded paved area came from the added paved area.
The Meerssen subcatchment is the most vulnerable to flooding. This subcatchment contains the most paved area and more runoff will result in a more flooded paved area. A completely paved Gulp subcatchment results in a less flooded paved area than building 6 km2 close to the Geul in the Meerssen subcatchment. When the Belgians build new houses in the Sippenaeken subcatchment, the Netherlands will receive more water during an extreme event such as in July 2021.
The letter Water en Bodem Sturend states that new houses must be built in sensible locations. In this research, the location of new houses is found to be important for the hydrological response. Building close to the river results in a more flooded paved area than building far from the river. The Gulp subcatchment is the least vulnerable to flooding and can be considered the best building location for new houses among the three investigated subcatchments.","","en","master thesis","","","","","","","","","","","","Water Management","",""
"uuid:001ae989-286d-4c5c-8976-be08ef46b71b","http://resolver.tudelft.nl/uuid:001ae989-286d-4c5c-8976-be08ef46b71b","Circuits and Systems for a Spiking Neuromorphic Network in 28 nm CMOS","Hettema, Bart (TU Delft Electrical Engineering, Mathematics and Computer Science)","van Leuken, T.G.R.M. (mentor); Zjajo, Amir (graduation committee); Bishnoi, R.K. (graduation committee); Delft University of Technology (degree granting institution)","2024","Neuromorphic computing can be used to efficiently implement spiking neural networks.
Such spiking neural networks can be used in edge AI applications, where low power consumption is paramount.
The use of analog components allows for extremely low power implementations.
This thesis contributes the designs of an analog spike generator, synaptic elements and an accumulating neuron in 28 nm CMOS technology.
The elements are assembled in a neural network and laid out in an SoC.
Energy consumption numbers of less than 1 pJ/synaptic operation are achieved in the analog neuromorphic components.","neuromorphic computing; spiking neural network; neuron; synapse; CMOS","en","master thesis","","","","","","","","","","","","Electrical Engineering | Circuits and Systems","",""
"uuid:915afc04-a802-456b-95d5-4e1c7dc49a25","http://resolver.tudelft.nl/uuid:915afc04-a802-456b-95d5-4e1c7dc49a25","Flying and Ground Robot Collaboration for Camera-based Search and Rescue","Esteves Henriques, Bernardo (TU Delft Aerospace Engineering)","Jamshidnejad, A. (mentor); Baglioni, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Search and Rescue (SaR) missions present challenges due to the complexity of the disaster scenarios. Most life losses and injuries occur in developing countries. Robotics has become indispensable for rapidly locating disaster victims. Combining flying and ground robots more effectively serves this purpose due to their complementary features. To this end, a cost-effective framework to perform conventional SaR tasks is presented. The method leverages You Only Look Once and video streams by an Unmanned Ground Vehicle (UGV) and an Unmanned Aerial Vehicle (UAV). In exploiting pose estimation to perform human depth estimation, the susceptibility of the algorithm to variations in poses was unveiled. In tracking object trajectories, the collaboration is advantageous in wide-area cluttered trajectories as opposed to narrow-area unobstructed trajectories. In mapping terrain elevation, errors drop significantly with the assistance of the UAV. Moving forward, devising adaptable strategies tailored to diverse SaR scenarios will be pivotal.","Search and Rescue Robotics; Computer Vision; Object Detection; Pose Estimation; Homography Estimation; State Estimation; Terrain Mapping","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:585d2724-7c36-4375-a99c-a3419f6ae9f6","http://resolver.tudelft.nl/uuid:585d2724-7c36-4375-a99c-a3419f6ae9f6","Numerical investigation of the effect of hardware parameters on atomic-ensemble-based repeater protocols","Stevense, Wesley","Wehner, S.D.C. (mentor); Horta Ferreira da Silva, F. (mentor); Delft University of Technology (degree granting institution)","2024","We perform a numerical optimisation of the hardware parameters of an atomic-ensemble-based single repeater setup. The setup operates on a real-life fiber network connecting the cities Delft and Eindhoven. Besides this network, the setup encompasses photon pair sources, quantum memories, single photon detectors, and 50:50 beam splitters. The corresponding hardware parameters we consider are the following;
- The detector efficiency, defined as the probability the photon detector correctly registers an incident photon.
-The detector dark count probability, defined as the probability that a detector registers a false detection event.
- The memory efficiency, defined as the maximum probability that an excitation is not lost in the quantum memory.
- The memory coherence time, defined as the characteristic time after which an excitation is lost in the quantum memory.
- The Hong-Ou-Mandel visibilty, which is a measure of the indistinguishability of the photons in the setup.
Additionally, the setup has the ability to be multiplexed. This means that the probabilistic processes essential for executing the repeater protocol are initiated $M$ times in parallel. This increases the performance of the protocol.
To achieve the optimisation, we introduce absolute minimal hardware requirements and minimal hardware requirements. An absolute minimal hardware requirement is defined as the least favourable hardware parameter that still allows the setup to reach a given target metric. This implies that all other hardware parameters are at their optimal value. Minimal hardware requirements are defined as the least favourable set of hardware parameters that still allow the setup to reach a given target metric.
To evaluate the aforementioned target metric we conduct a numerical analysis. This analysis is based on the entanglement based version of quantum key distribution. We use Netsquid, a discrete event simulator for quantum networks, to carry out the numerical analysis. Utilising this, we formulate an optimisation problem that allows us to find absolute minimal hardware requirements and minimal hardware requirements for an atomic-ensemble-based single repeater setup.
We develop a method to solve this optimisation problem. This allows us to find absolute minimal hardware requirements and minimal hardware requirements for the hardware parameters listed above. We do this for different number of multiplexing modes, and different node placements on the existing fiber network. We consider both perfect photon pair sources and a model of a photon pair source based on Spontaneous Parametric Down Conversion (SPDC).","Quantum repeaters; atomic ensembles; absolute minimal hardware requirements; minimal hardware requirements","en","master thesis","","","","","","","","","","","","Applied Physics","",""
"uuid:7a6ee58b-af74-450a-a54b-8511aae898e6","http://resolver.tudelft.nl/uuid:7a6ee58b-af74-450a-a54b-8511aae898e6","Model-based testing of simulation models: A case-study approach to test model design for automated testing of discrete-event simulation models","van Bergeijk, Ferd (TU Delft Technology, Policy and Management)","Verbraeck, A. (mentor); Huang, Yilin (graduation committee); Quispel, O. (graduation committee); van den Berg, Tom (graduation committee); Delft University of Technology (degree granting institution)","2024","Model-based testing (MBT) is applied for the verification of simple simulation models used in modeling & simulation for decision-making. It is found that MBT of simulation models is not discussed much in literature, and that existing case studies on this topic do not give guidelines for test model design. It is established that testing simulation models is a difficult problem, as simulation models have many states, a time component, reactiveness, and inherent stochasticity. It is hypothesized that MBT could lead to more efficient and effective testing, and could fit within a modular approach to verification of simulation models. A focus is made on verification that discrete-event simulation models meet their functional requirements, by using automated test packages.
Options for test model design are explored in three case studies where automated test suites are developed for three simple simulation models that form the systems under test (SUT). Options from existing taxonomies are first selected for this, based on their relevance to the properties of simulation models that make dynamic verification difficult. In the process, an existing MBT software tool is selected and evaluated.
The main aspects of MBT that are explored are: nondeterministic test models and SUTs, transition-based test models, online and reactive test execution, specification of oracles at different levels, time advancement of the SUT, the distinction between black-box and white-box approaches, and the problem of test abstraction. Examples are made where the test model, an extended finite state machine (EFSM), is an abstract version of the SUT, that includes its most relevant state transitions. An approach to testing is used, where the test model follows the SUT’s state and selects relevant assertions accordingly. This approach limits the use of stochasticity in the test model, that is often done in MBT.
It is found that MBT can be useful for three types of dynamic verification: of the dynamic behavior, of the (end) results, and of the response to inputs. The first type is explored with a step-by-step approach where oracles are checked after each time advancement in the SUT. The second type is implemented without the use of MBT techniques, by extending the functionality of an existing MBT tool to allow for analysis of multiple simulation runs. The third type is not explored but approaches for it are defined.
The project shows the feasibility of MBT of simulation models and shows different options for test model design. Not discussed are the adequacy of the developed test packages in detecting faults, and the efficiency, effectiveness and quality of MBT for simulation models in general.
When providing public transport, it is important to have good services, which support the industry of public transport. Without these services, people will associate travelling by public transport with something negative. In Rotterdam there are three locations which are important in the infrastructure of public transport. Rotterdam CS, Beurs, and Zuidplein are the main stations where various forms of transportation can be used by customers. RET provides an extra service at these locations in the form of service points. Every day, employees of the RET help their customers to have a relaxed and pleasant journey. The problem is that the contemporary service points are getting outdated and do not fully fulfill the needs and wishes of RET’s customers and employees anymore.
The world of public transport is changing. For years buses, trams, and metros have been the main solution when travelling by public transport. However, times are changing, and so is public transport. Shared mobility is getting more popular by the day. In Rotterdam there are various forms of shared mobility like bicycles, e-scooters, and shared cars. More and more these kinds of companies are becoming new competitors in the world of public transportation.
To stay relevant in the rapidly changing world of public transportation, a new kind of SP is needed. The project ‘New generation service store for RET’ was conducted to find a solution for the outdated SP at Rotterdam CS. During the project, a literature review based on research was done. There was an active involvement of RET employees and RET customers for developing a new kind of Mobility store. By making drawings and turning them into a virtual reality environment, people were able to assess the designed environment and see if it fulfilled their needs and wishes.
This project concludes with recommendations for the design of a Mobility store, which could be established at the passage of the Rotterdam CS’s metro hall.
This thesis focuses on the application of block compressed sensing to signals of high dimension to gain insight into the relation between reconstruction performance and computational complexity. This is done by, first investigating how theoretical reconstruction guarantees change, when the problem is divided into smaller sub-problems and by doing a complexity analysis of the reconstruction itself. Each sub-problem solves for a portion of a signal, defined as a block. Next, experiments are conducted in order to get insight into the trade-off between computational complexity and quality of the reconstruction. It can be found that, by using this block-wise approach, the computational complexity of the reconstruction problem decreases, but at the same time, quality of the reconstruction deteriorates. Besides, a method to compensate for this performance loss is proposed. The key idea of this method is that, by propagating prior information among the different blocks, the reconstructions of the blocks can be improved. Finally, block compressed sensing and prior-aware block compressed sensing are analysed in a higher order tensor compressed sensing setting. Nevertheless, this setting was found to exhibit a less favourable complexity-performance trade-off than the normal one, as this setting resulted in both a more complex and a less accurate reconstruction than the normal one.","","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:1019957f-906a-4ca3-9abe-e1ae9479ef4f","http://resolver.tudelft.nl/uuid:1019957f-906a-4ca3-9abe-e1ae9479ef4f","Coherent manipulation of normal and Andreev fermions","Vilkelis, K. (TU Delft QRD/Wimmer Group)","Akhmerov, A.R. (promotor); Wimmer, M.T. (copromotor); Delft University of Technology (degree granting institution)","2024","A large part of condensed matter physics concerns itself with understanding the behaviour of electrons in solids and finding ways to control them. However, in mesoscopic systems (i.e., systems with nanometer to micrometre scale), the behaviour of electrons is difficult to predict through the Schrödinger equation. Instead, it is often more fruitful to use an approximate semiclassical theory that re-introduces the concept of particle trajectories into the quantumworld. These trajectories not only depend on the applied external fields but also on the Fermi surface of the material itself. The control over the Fermi surface allows to engineer electron trajectories not present in classical physics and therefore leads to new novel phenomena. For example, in highly anisotropic materials with open Fermi surfaces, the semiclassical trajectories of electrons in a magnetic field are no longer closed but instead move in an oscillating open trajectory that travels from one sample edge to the next. These open trajectories result in magnetoresistance oscillations with a period proportional to the flux passing through the sample—similar to the Aharonov–Bohm effect. However, unlike the Aharonov–Bohm effect, the magnetoresistance oscillations here are not due to interference effects....","Andreev bound states; semiclassical methods; Majorana bound states; hybrid superconducting devices; Quantum transport","en","doctoral thesis","","978-94-6384-535-9","","","","","","","","","QRD/Wimmer Group","","",""
"uuid:26e3395c-ff44-4ccb-9bf5-c6b0529d41f7","http://resolver.tudelft.nl/uuid:26e3395c-ff44-4ccb-9bf5-c6b0529d41f7","Deciphering Learning Curve Characteristics via K-Means Clustering of Curve Model Parameters","Ozgur, Enes Arda (TU Delft Electrical Engineering, Mathematics and Computer Science)","Turan, O.T. (mentor); Viering, T.J. (mentor); Hung, H.S. (graduation committee); Delft University of Technology (degree granting institution)","2024","Learning curves illustrate the relationship between the performance of learning algorithms and the increasing volume of training data [1, 2, 3]. While the concept of learning curves is well-established, clustering these curves based on fitting parameters remains an underexplored area. Our study delves into this domain and leverages the Learning Curve Database (LCDB) to discover potential patterns. We investigate whether different curve models uncover distinct patterns, examine the impact of different datasets on these learners, and explore if various learners display unique characteristics and behaviors or adhere to a common pattern. Curve model analyses conclude that most of the data points are in a single cluster (dominant cluster), indicating a potential commonality. Certain learners, such as QuadraticDiscriminantAnalysis and PassiveAggressiveClassifier, exhibit unique traits and do not conform to this common pattern, regardless of dataset attributes. Moreover, while various learners demonstrate similar characteristics within a single curve model, distinct patterns emerged when comparing across different curve models, indicating internal similarity but external divergence in behavior.","Learning curve; clustering; curve model","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:35022c6f-0eff-4873-bad9-fee3595d2594","http://resolver.tudelft.nl/uuid:35022c6f-0eff-4873-bad9-fee3595d2594","Exploring an omni-channel service proposition in music event ticketing: at CM.com","de Jongh, Ruben (TU Delft Industrial Design Engineering)","Hultink, H.J. (mentor); Secomandi, Fernando (graduation committee); Huijgers, Bandy (graduation committee); Delft University of Technology (degree granting institution)","2024","CM.com is a conversational commerce company specialised in offering solutions in CPaas (Communication Platforms as a service). One of the industries to which they point their ‘software as a service’ is music event ticketing. With their General Admission (GA) Ticketing product, CM provides event organizers with a platform to set-up their ticket sales process, sell tickets, handle event registrations, communicate with visitors, and support other event logistics.
The recent COVID-19 pandemic has had a significant effect on consumer behaviour related to music events and festivals. Event organizers must innovate in their offering to stay relevant to consumers within the overcrowded market. This has led to changes in organizer’s needs and priorities regarding their ticketing platform. CM needs to respond in their service offering to stay relevant in the market and fulfil their client’s needs. In combination with the desire to leverage the potential of their product portfolio better, CM seeks to identify new opportunities in the way their ticketing product is designed and delivered to their client.
The project involves creating a holistic perspective of the project context and involved stakeholders through gathering extensive qualitative data, taking a service design perspective. The gathered information serves as fundamental knowledge to co-create towards a new strategic service proposition, combining user-research, industry trends and strategic competitive positioning with CM’s technological potential.
The results conclude CM’s ticketing product should be developed towards “Facilitating the Easy creation of Rich & Effective omni-channel communication touchpoints for event organisers.” This proposition aims to facilitate organisers to adopt a progressive, data-driven approach to communication between organiser and consumer. Data allows for effectively targeting consumers in a personalized way, boosting the conversion of communication touchpoints. Working with this data proposition should be designed for non-data experts, making the workflow for the creation of data driven communication touchpoints as easy as possible. Ultimately, the proposition seeks to enable organizers to create more points of engagement between organiser and consumer over a rich array of channels and purposes, contributing to a unique and pleasant visitor experience.
To deliver this value proposition to clients, three development stages must be completed. Firstly, the focus should be put on improving the fundamental functionalities through which organisers gain knowledge through data, whereafter its usability should be improved. Finally, the communication possibilities to improve the visitor experience should be enriched. The proposed final service proposition is concretized through UX-use cases, illustrating the proposed user-flow on an interaction level.
Due to CM’s unfamiliarity with the design process and the different internal project teams working in silos, additional guidance is provided to embed the project outcomes effectively. The guidance in the shape of a visual overview describing the service proposition’s value in terms of desirability, viability, and feasibility aims to persuade company-wide value. However, this does not guarantee implementation within CM. Additionally, a “From Research to Development Guide” facilitates the product team to work towards the proposed service proposition with the created product materials, ensuring a user-centred process.","Service Design; User-Centered Design; Entertainment; Music industry; Strategic design; Strategic Innovation","en","master thesis","","","","","","","","","","","","Strategic Product Design","",""
"uuid:54b8e5a5-fcf3-4636-8b1b-a0580f2e3bbe","http://resolver.tudelft.nl/uuid:54b8e5a5-fcf3-4636-8b1b-a0580f2e3bbe","Selective Reflections: A light and sound installation using spectral tuning to play with depth perception","Ammerlaan, Bas (TU Delft Industrial Design Engineering)","Pont, S.C. (mentor); Smit, C.R.G. (graduation committee); Aerts, S.J.W. (graduation committee); Delft University of Technology (degree granting institution)","2024","The project originated with the goal of creating an interactive light and sound installation for Highlight Delft, an innovative art and technology route. This involved incorporating holographic projection and spectral tuning to convey a specific perceptual phenomenon. The initial phase included extensive research into holographic projection, spectral tuning, and a broad literature review on perception. Experimentation with acquired knowledge informed the practical application, distinguishing effective principles and guiding the design process.
From the experimentation phase, three design directions emerged, with the idea of projecting coloured visuals on multiple layers of semi-transparent textile standing out. Tuning the projection in terms of colour and timing allowed visuals to move between the textile layers. By integrating storytelling into the concept a design brief emerged. However, during the development of the first concept, the design brief missed focus, leading to more complex ideas. Emphasizing communication, the focus shifted to conveying how spectral tuning can influence depth perception in the current setup. This resulted in the emergence of concept 2 with a simplified design involving two layers of textile and a projector.
A preliminary test of concept 2 revealed a need for additional information to enhance understanding and appreciation. The addition of an illustrative introduction before experiencing the installation, significantly improved attributes such as perceived depth, beauty, immersion, engagement, and coherence. These insights guided refinements in the final design, including a shortened visual narrative, added audio for increased engagement, and an elaborate exhibition space design. Attention was consistently committed to communication at various levels.
A final validation test produced varied results but consistently high scores on every attribute. Feedback and recommendations from the test were wellreceived, eliminating ambiguities. Even individuals outside the test expressed enjoyment of the experience. Despite the project’s initially broad scope, a focused approach, particularly in communication, developed in a final design that communicates clearly and evokes joy and interest in viewers.","Spectral tuning; Projections; Perception; Depth Perception; Chromostereopsis; Lighting; Lighting design; Experience Design","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:3b23b63b-69be-4c0e-90c0-3312eae1d871","http://resolver.tudelft.nl/uuid:3b23b63b-69be-4c0e-90c0-3312eae1d871","Distributed Acoustic Sensing using straight, sinusoidally and helically shaped fibres for seismic applications","Al Hasani, M.M.K. (TU Delft Applied Geophysics and Petrophysics)","Drijkoningen, G.G. (promotor); Wapenaar, C.P.A. (promotor); Delft University of Technology (degree granting institution)","2024","Distributed Acoustic Sensing (DAS) is a versatile dynamic strain sensing method that has been adopted for a wide range of seismic applications. In DAS, optical fibres are interrogated and used as sensors, where a strain or strain-rate measurement is made along a specific length of the fibre, called the gauge length. Its main appeal is the spatially dense data over long distances. The main limitations of DAS, however, are that it is mainly sensitive along the axial direction of the fibre and that the signal-to-noise ratio is worse than that of standard geophones. The first issue limits its adoption in surface reflection seismic when the fibre is deployed horizontally. Also, due to the very nature of the measurement (i.e. elongation and contraction of the fibre), it is commonly considered as a single-component measurement, therefore it lacks the information from the other components.
This thesis studies the potential of obtaining multi-component information from DAS as well as investigating the use of combined fibre configurations for surface-seismic applications. We approach this by examining several fibre-shaping approaches with static and dynamic strain measurements. First, the concept of the sinusoidally shaped fibre is examined to make a directional strain sensor in a direction other than the fibres’ axial direction using a static-strain approach. Secondly, the combined use of straight and helically wound fibres for obtaining multi-component information from DAS data as well as assessing the usefulness of using such a combination is investigated in a surface-seismic setting.'
Using the sinusoidally shaped fibre, two approaches are investigated. The first approach involves the use of the sinusoidally shaped fibre embedded in a homogenous material. An analytical model is presented to describe what happens to the deformed fibre in three main directions, which was validated via a finite-element model. Along with the model, loading experiments were performed on a sinusoidally shaped fibre embedding in a polyurethane-type (i.e. called Conathane®) strip in the following directions: in-line (i.e. transversal in-plane with the sinusoidal fibre), broadside (i.e. perpendicular to the sinusoidal fibre), and along-strip (i.e. along the strip’s longest dimension). We saw that the fibre is mainly sensitive to the in-line and broadside directions, and it is slightly more sensitive in the in-line direction relative to the broadside direction. We also saw that the geometrical parameters of the fibre, as well as the mechanical properties of the embedding material, affect its directional sensitivity. This is exploited in the second approach where the embedding material is now adapted to a low Poisson’s ratio metamaterial as well as further adaptations in the geometry of the fibre, aiming to create a unidirectional strain sensor. Experimental results showed improvements in the sensitivity but not as much as predicted by the analytical or numerical modelling.
Using DAS in field settings, multiple configurations of straight (SF) and helically wound fibres (HWF) with different wrapping angles (α) were buried in a 2-m trench in farmland in the province of Groningen in the Netherlands. Significant amplitude differences are observed between the straight and helically wound fibres. It is observed that shaping the fibre into a helix dampens the amplitude inside the surface wave significantly. Also, a polarity flip is observed with the use of HWF with a wrapping angle of 30◦. This hints that there is a contribution of the vertical component on the response measured by the HWF as also supported by the theoretical models. The reflection response is also examined using a set of engineered SF and HWF fibres. The main seismic reflections are present in both fibres with higher amplitude in SF compared to HWF, contrary to what was expected. Also, using post-stack images we see that the SF and HWF provide reflection structural images comparable to surface-deployed geophones but with an (expected) lower signal-to-noise ratio. We show that the combined use of SF and HWF is useful, as reflections were better shown for the shallow section, unlike HWF which provided better reflections in deeper sections. Furthermore, we discuss the effect of gauge length on the retrieval of surface waves along with the use of different fibre shapes using active and passive sources.
With the active-source data, we show that the gauge length plays an essential role in the retrieval of surface waves depending on their wavelength range, as it might cause distortions in the waveform which appears as notches in the (frequency, horizontal-wavenumber)–domain, as well as complicates picking the dispersion curves of these waves. On the other hand, the helically wound fibres might require a longer gauge length to retrieve the surface wave properly. This decreased sensitivity of the helically wound fibres is also shown from virtual shots obtained by passive interferometry as well as a recorded earthquake in the area.","Acquisition; Distributed Acoustic Sensing; shaped fibres; field experiments","en","doctoral thesis","","978-94-6384-531-1","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:cf13188c-7632-4929-ae08-9465f909f0e5","http://resolver.tudelft.nl/uuid:cf13188c-7632-4929-ae08-9465f909f0e5","Examining the Efficacy of Persuasive eHealth Applications in Facilitating Smoking Cessation: An Analysis of Competency Based Activities","Maguire, Aaron (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Interactive Intelligence)","Albers, N. (mentor); Brinkman, W.P. (mentor); Wang, H. (graduation committee); Delft University of Technology (degree granting institution)","2024","To assist smokers in potentially quitting their habit, this paper investigates digital eHealth applications. Based on a dataset provided by research into an eHealth application, it aims to determine if persuasive activities can convince users of the usefulness of competencies determined to assist in quitting smoking. A thematic analysis was used on the participant's qualitative responses to the activities. Using this and the quantitative data derived, insights into the efficacy of persuasion were determined.
It was determined that engagement with the optional qualitative aspect of the data produced similar utility perspectives on the competencies to those who did not comment. It was noted that the general perspective of the competencies rose after completing the activity, however not to a significant degree. Additionally, no notable correlations between age, gender or educational level and increased perception of the competency arose. Several interesting remarks from participants were analysed to offer considerations for any future research in this field.","Smoking Cessation; Persuasive Activities; eHealth","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:ff17c63f-5bf4-4cd2-9e1f-b7f86d41a0c4","http://resolver.tudelft.nl/uuid:ff17c63f-5bf4-4cd2-9e1f-b7f86d41a0c4","The Implementation of Evaporated Ethanol as an Alternative Fuel for the Natural Gas-Fired Power Plant in Killingholme","van Eil, Tijn (TU Delft Mechanical, Maritime and Materials Engineering)","Klein, S.A. (mentor); Pourquie, M.J.B.M. (graduation committee); Abbott, David (graduation committee); Delft University of Technology (degree granting institution)","2024","Decarbonization is an important step to achieve the goals set by the Paris Agreement. Greenhouse gas emissions should be reduced to zero, and therefore, the reliability of fossil fuels should be reduced. This causes a shift of interest towards more renewable solutions. However, the intermittent nature
of renewable energy sources such as solar and wind energy leaves a gap in the energy supply. Currently, this gap is still filled by natural gas, but biofuels could potentially help in decarbonizing this gap. Biofuels could be prevaporized and used as an alternative fuel within existing natural gas-fired power plants. Ethanol is an interesting biofuel as it has a relatively low boiling point, meaning that it is relatively easy to evaporate. Next to that, ethanol has a similar Wobbe Index (WI) compared to natural gas, meaning that it could be potentially used with only minor adjustments to the gas turbine. This research will focus on implementing ethanol as an alternative fuel for the Killingholme power plant, a
600 MW power plant in an open cycle gas turbine (OCGT) configuration that Uniper operates in the United Kingdom.
This research focused on the effect of ethanol on the process design and combustion characteristics, where the process design was only briefly touched upon. It was found that ethanol should be heated to a temperature of 467 K to be in vapor form at the relevant gas turbine conditions. A process design was
made for the baseload operation, where the required heat for the evaporation process was provided by the flue gas flowing out of the gas turbine. Next to that, the use of ethanol requires slightly higher volume flow rates, meaning that the pipes and fittings should be adjusted to keep the desired fuel pressure. The effect of ethanol on combustion characteristics was researched by a kinetic modeling study and a CFD study focusing on fuel-air mixing, where the results will be compared to methane. A RANS study was performed for the CFD study, which showed that the use of ethanol results in a better quality of mixing. From the kinetic modeling study, it was found that ethanol has a lower autoignition
delay time than methane. This will probably not lead to the autoignition of the fuel-air mixture in the mixing section, but it could lead to periodic flashes in regions close to the recirculation zones within the burner. It was also found that ethanol has a 78% higher laminar flame speed than methane. Next to that, it was found that ethanol has an effective Lewis number of 1.56 at the relevant gas turbine conditions, whereas methane has an effective Lewis number close to unity. From the laminar flame speed and the effective Lewis number, it was concluded that the use of ethanol results in an increase in turbulent flame speed. The increased turbulent flame speed and better quality of mixing of ethanol suggest a decrease in flame length. The decrease in flame length and increase in turbulent flame speed lead to higher flashback risks, but it is expected that this will be within the flashback margin of the burner. Based on the kinetic modeling study and the fuel-air mixing study, it was concluded
that ethanol will have NOx emissions similar to methane and that the driving energy source of the combustion dynamics will probably shift to higher frequencies.
Recommendations for further research are the gas turbine’s start-up, ethanol contaminants, extended CFD study of the burner, and the blending of ethanol and natural gas. Further research could complement the already promising results from this report, and eventually, this could lead to combustion tests where ethanol will be used as fuel.","Gas Turbine; Ethanol; CFD; Kinetic Modelling; Killingholme","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Energy, Flow and Process Technology","",""
"uuid:d079f994-2b7c-4f2d-af55-f51568a9b8f6","http://resolver.tudelft.nl/uuid:d079f994-2b7c-4f2d-af55-f51568a9b8f6","The Hotel—Migrant Segment: Catching Lives","Gkikas, Thomas (TU Delft Architecture and the Built Environment; The Berlage Center for Advanced Studies in Architecture and Urban Design)","Frausto, S.E. (mentor); Bouše, P. (mentor); Groothuijse, B. (mentor); Delft University of Technology (degree granting institution)","2024","Catching Lives is a Migrant hotel segment that shelters those on long-term relocation. It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Day segment propositions
1. The Day segment sifts through New York City’s multiplicity of crowds.
2. The Day segment is a 24/7 hub at the base of the skyscraper.
3. The Day segment goes beyond the traditional day-hotel model through its diversification of room types, supporting activities, and retail options.
4. The Day segment makes itself financially feasible by pooling resources such as foot traffic, infrastructure, and labor.
5. The Day segment offers a range of fleeting intimacies somewhere between commodity and serendipity.
Additionally, a baseline model, namely Probabilistic Principal Component Analysis (PPCA), was selected for a comparative analysis to generate the underlying latent space to test the hypothesis that a type of Variational Autoencoder (VAE) can be used to learn a reduced-dimensional latent space for configurations of a kinetic pathway model. A dataset comprising 5000 hypothetical configurations of a kinetic pathway model was utilized to extract relationships between elements of a kinetic pathway.
The results indicate that PPCA can model the underlying distribution of the dataset when the latent space is large enough. However, the traditional CVAE might struggle to capture the underlying distribution, resulting in an entangled latent space. The study suggests that an implementation of $\beta$-CVAE could lead to a better balance between parts of the objective function during training, offering improved prospects for generating cost-efficient kinetic pathways for combinatorial pathway optimization experiments.","Metabolic Flux Analysis; Variational Autoencoder (VAE); Probabilistic analysis; Principal Component Analysis (PCA); Combinatorial Optimization","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:f38826d3-deb6-4c4c-b2de-4f7fc6b6e0cf","http://resolver.tudelft.nl/uuid:f38826d3-deb6-4c4c-b2de-4f7fc6b6e0cf","Navigating Repositories: Assessing the Impact of External Repositories on Packages in Maven Central","Sandifort, Jelle (TU Delft Electrical Engineering, Mathematics and Computer Science)","Proksch, S. (mentor); Huang, S. (mentor); Poulsen, C.B. (graduation committee); Delft University of Technology (degree granting institution)","2024","This paper presents a comprehensive experimental study on the use and impact of external repositories in the Maven ecosystem. For this research the prevalence, naming patterns, and potential risks associated with external repositories were analyzed. We analyzed 199,188 packages and found that 3.29% of projects employ external repositories. Our findings indicate a decline in the usage of external repositories over time, with one (1.85%) and two (0.72%) external repositories occurring the most. The usage of external repositories has no significant (p < 0.05) effect on the error rate. However, 19.85% of the errors of packages that use an
external repository are caused by one of their external repositories. Moreover, we found that 69.58% of the repository urls were unreachable. 19.31% of the unique ids have two or more different repository urls associated with them. Based on our findings, developers are urged to thoroughly evaluate their usage of external repositories and to consider checking their settings.xml and POM.xml files to
ensure no url or id collisions are prevent or causing unintended behaviour.","Maven; external repositories; repository naming; dependency resovability; artifact repository","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:db10db39-5bdc-48c7-b415-2d150f44f12f","http://resolver.tudelft.nl/uuid:db10db39-5bdc-48c7-b415-2d150f44f12f","Pedestrian Interaction Modelling: Leveraging Trajectory Prediction for Belief Representation","Weinans, Tom (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Cognitive Robotics)","Zgonnikov, A. (mentor); Siebinga, O. (mentor); Mészáros, A. (mentor); Kober, J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Autonomy in traffic (e.g., autonomous vehicles) could potentially benefit mobility, safety, accessibility and sustainability. However, the realisation of these advancements is highly dependent on how effective these autonomous vehicles interact with vulnerable road users such as pedestrians. Before we can understand how pedestrians will interact with autonomous vehicles, it is essential to understand how pedestrians interact among themselves in interactive traffic scenarios. Previous studies have focused on describing these scenarios with probabilistic trajectory prediction methods such as TrajFlow. However, these approaches often fall short in capturing the nuances of mutual interactions. Simple interaction models have been proposed that can describe these interactions, but neglect the influence of another person's intentions. To address this issue, in existing work the Communication-Enabled-Interaction (CEI) framework was proposed that describes interactions by modelling communication and a belief of another person's intentions. The idea of using beliefs in interaction modelling is based on the concept that people have a general but uncertain idea about the plans of other people. These beliefs are one of the fundamental aspects of the CEI framework and must therefore contain valuable information about possible decisions. That is why this study investigates the use of the probabilistic trajectory prediction method TrajFlow for the belief construction of the CEI framework. TrajFlow is trained on the belief-based Forking Paths dataset, integrated into the CEI framework, and tested in four simulated pedestrian interaction scenarios. The analysis shows that the framework is able to simulate plausible interaction behaviour, dealing with conflicting goals and trajectories in multiple simulations. By doing so, this study takes a positive step towards modelling pedestrian interactions and contributes to the broader goal of realising the benefits linked to autonomy in traffic.","Pedestrian behaviour; Interaction modelling; Trajectory prediction","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:1db8a068-399e-4094-998b-a202abbbcd74","http://resolver.tudelft.nl/uuid:1db8a068-399e-4094-998b-a202abbbcd74","The Hotel—Capsule Segment: Capsule Metro","Tan, Yuhe (TU Delft Architecture and the Built Environment; The Berlage Center for Advanced Studies in Architecture and Urban Design)","Frausto, S.E. (mentor); Bouše, P. (mentor); Groothuijse, B. (mentor); Riedijk, M. (mentor); Delft University of Technology (degree granting institution)","2024","Capsule Metro is a capsule hotel segment that treat cheapskates with a good deal. It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Capsule Segment Propositions:
1. The Capsule segment provides a temporary rest stop in the center of Manhattan, a simple and affordable space after long hours of work.
2. The Capsule segment arranges the space and circulation between the skyscraper’s infrastructure and lodging near the core, creating a cozy temporary resting stop surrounded by cluttered service spaces.
3. The Capsule segment t formulates the physical space of the capsule by considering different postures and perceptions of minimum comfortable distances.
4. Despite being adjacent to other hotel segments with various statuses, the Capsule segment nests in the elevator corridor with a vertical arrangement, providing anonymity and indifferent contact with limited amenities.
5. The Capsule segment provides an affordable option for temporary stays in New York City, alleviating financial burdens and enabling visitors to enjoy what the metropolis offers.","Hotel; New York City; skyscraper; Cheapskate; capsule","en","master thesis","","","","","","http://thehotel.theberlage.nl/","","","","","","The Berlage Post-MSc in Architecture and Urban Design","ARB301",""
"uuid:d6173944-d4c0-414a-8bca-9918676ec4bf","http://resolver.tudelft.nl/uuid:d6173944-d4c0-414a-8bca-9918676ec4bf","The Hotel—Family Segment: The Campground","Verheyden, Felix (TU Delft Architecture and the Built Environment; The Berlage Center for Advanced Studies in Architecture and Urban Design)","Frausto, S.E. (mentor); Bouše, P. (mentor); Groothuijse, B. (mentor); Riedijk, M. (mentor); Delft University of Technology (degree granting institution)","2024","The Campground is a family hotel segment that family hotel that all members of the nuclear family can enjoy.. It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as a type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as a landmark—The Metropolitan—and the hotel as a tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Family Segment Propositions:
1. The nuclear family seeks to reconnect through discovery.
2. The skyscraper provides a range of explorable facilities.
3. The Family segment creates shelters in the urban jungle.
4. The playground brings people together.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Single Women’s segment Segment Propositions:
1. The Single Women’s segment supports women as they face safety concerns, difficulty navigating New York City, and an increasing cost of living.
2. Elevated high in the skyscraper, the segment’s private floors are connected to the vertical city of the skyscraper through program and public spaces designed for women.
3. The Single Women’s segment caters to solo travelers and career-focused women through a kind of new domesticity, accommodations for a variety of budgets, and protection within a secure boundary.
4. The Single Women’s segment advocates for women across One Hotel, through safety measures, caregiving spaces, and hotel programming that empowers.
5. The Single Women’s segment is a place for social exchange among women.
In particular, using a known dataset of Scratch projects, which we enriched with new projects, we examined several independent variables that capture sentiment on comments from different perspectives, e.g. the absolute or relative number of comments with a particular sentiment score that a user receives, or the ratio of comments that fall in a certain category. We also examined several dependent variables that capture the creator's inclination to continue producing projects, e.g. the number of projects they create or the total time that they are active on the platform.
The results of our experiments reveal that the absolute and relative number of comments with a specific sentiment score given to a user have a low correlation to the time that a user is active on the platform. Additionally, the ratio of the number of positive and negative comments over the total number of comments given to a user has a low correlation to the time that a user is active on the platform. Finally, the number of comments that a user receives has a low correlation to the number of projects a user creates.","Scratch; sentiment; comment; User Participation; Sentiment Analysis","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:7c4e99dc-3af0-4187-8988-f8862924414d","http://resolver.tudelft.nl/uuid:7c4e99dc-3af0-4187-8988-f8862924414d","A Mismatch Relaxation to the Primer Selection Process of an Amplicon Sequencing Algorithm","Polimac, Dean (TU Delft Electrical Engineering, Mathematics and Computer Science)","Baaijens, J.A. (mentor); van Bemmelen, J. (mentor); Raman, C.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","In this study we introduce a different approach to the primer selection problem in the AmpliDiff [12] algorithm. Two different metrics, being the Hamming distance [2], and the Levenshtein distance [4], are used to compute sets of similar primers. This is done such that locations where mismatches between the primers and the target sequence can occur are determined by the locations of similar primers. The impact that said mismatches have on the solution set of amplicons and their respective primers is outlined. With this we show potential benefits of allowing mismatches to occur, as well as their drawbacks.","Primer Selection; Primer Mismatch; AmpliDiff","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:e80e5662-612e-4b16-9e68-d5d3934ac635","http://resolver.tudelft.nl/uuid:e80e5662-612e-4b16-9e68-d5d3934ac635","An analysis of Java release practices on GitHub","Roest, Vivian (TU Delft Electrical Engineering, Mathematics and Computer Science)","Proksch, S. (mentor); Poulsen, C.B. (graduation committee); Delft University of Technology (degree granting institution)","2024","This paper examines the release practices of Java Maven Repositories on GitHub. Most prior research in this vein has been done on Maven Central, the largest Maven package repository. However, GitHub hosts 15.5 million Java repositories, and is left untapped. Additionally of interest is the fact that GitHub provides a competitor to Maven Central, GitHub packages. To this end, the paper establishes an index of all Java repositories on GitHub. Furthermore, this dataset also includes Maven configuration (POM.xml) files. Additionally, an in-depth analysis is done of a sample of 500 000 of those 15.5 million repositories. This sample ended up containing 170 798 Java Maven repositories that had those POM.xml files. In this sample we discovered that of those 170 798, 6 507 (≈ 3.8%) had set up distribution configuration. Maven Central ended up being the most popular but GitHub packages and others ended up being quite popular as well. In the external repositories configured in those Java projects we notice a distinct lack of GitHub packages, other repositories were still present. We theorize that the lower popularity of GitHub packages is because it requires authentication, which is not trivial to set up. We discuss several approaches that can improve this situation.","Java; Maven; GitHub; scraping; Maven Central; data acquisition","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:af3e4e41-27fc-4f4b-9d46-e46707e59d46","http://resolver.tudelft.nl/uuid:af3e4e41-27fc-4f4b-9d46-e46707e59d46","Towards Effective Smoking Cessation: Understanding the Needs of Daily Smokers from eHealth Chatbot Interactions","Iftimescu, Vlad (TU Delft Electrical Engineering, Mathematics and Computer Science)","Albers, N. (mentor); Brinkman, W.P. (mentor); Wang, H. (graduation committee); Delft University of Technology (degree granting institution)","2024","Smoking has been one of the great threats to health in recent years, being strongly correlated with multiple negative health consequences, including lung cancer. Recent research suggests that artificial intelligence chatbots can be effective in persuading healthy behavior change. However, these chatbots usually rely on persuasive techniques to achieve their goal. Such techniques depend on identifying and meeting users' needs to be effective. To help improve understanding of the domain of healthy behavior change, we proposed a study which analysed the needs of daily smokers as they emerged from their interactions with a chatbot specifically designed to help them quit. The study performed a thematic analysis on users' free-text feedback, from which a set of 8 themes that directly correspond to 8 different needs were observed. The user needs were correlated with their genders, ages and highest completed education levels. While most of the results indicate that there is no significant correlation between the needs and user characteristics, which suggests that user needs are evenly distributed, certain correlations were highlighted for further analysis.","Smoking Cessation; Needs; Characteristics","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:7f9959a8-2290-4258-b82c-0b80d373a2f7","http://resolver.tudelft.nl/uuid:7f9959a8-2290-4258-b82c-0b80d373a2f7","Optimizing strains in Metabolic Engineering: comparative analysis of β-Conditional Variational Auto-encoder and Probabilistic PCA for synthetic data generation","Kirbeyi, Doruk (TU Delft Electrical Engineering, Mathematics and Computer Science)","Abeel, T.E.P.M.F. (mentor); van Lent, P.H. (mentor); Hanjalic, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","This research explores the landscape of dataset generation through the lens of Probabilistic Principal Component Analysis (PPCA) and β-Conditional Variational Auto-encoder (β-CVAE) models. We conduct a comparative analysis of their respective capabilities in reproducing datasets that mirror the distribution of the original data that comes from a hypothetical pathway kinetic model based on an E.coli strain using varied parameter settings falling within a specified range. The requirement of significant prior investment in acquiring accurate details about the distinct mechanisms governing each reaction and its parameters for the construction of these kinetic models push us to find alternative ways to generate data that guide metabolic engineering processes. This paper tries to find a viable option through compression algorithms that reduce dimensionality. The PPCA model demonstrates commendable fidelity in capturing overarching patterns, though areas for refinement in reproducing specific data points are identified. In contrast, the β-CVAE model exhibits higher fidelity, precision, and consistency, positioning it as a robust choice for data generation tasks. This study was constrained by both time and the specificity of the model architectures and the dataset. These limitations underscore the imperative for continual exploration and refinement within the dynamic landscape of generative modeling. Opportunities could be found in the refinement of both VAE, CVAE and β-CVAE models utilizing varied hyperparameters alongside different architectures, to increase applicability across diverse datasets within the realm of metabolic engineering.","Generative Models; β-Conditional-VAE; Metabolic Engineering; Strain Optimization; Synthetic Data Generation","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:559a64dc-62ae-47ce-b9dc-4e2cb56b6e27","http://resolver.tudelft.nl/uuid:559a64dc-62ae-47ce-b9dc-4e2cb56b6e27","Effects of Artifact Age on Maven Dependency Resolution","Kuļikovskis, Gints (TU Delft Electrical Engineering, Mathematics and Computer Science)","Proksch, S. (mentor); Poulsen, C.B. (graduation committee); Delft University of Technology (degree granting institution)","2024","This study conducts an investigation of the challenges faced by aging projects in Maven Central, focusing on the issue of missing dependencies. Using the Maven Explorer indexer, we systematically examine the correlation between the age of a project and the frequency of dependency resolution failures. Our analysis reveals a notable trend: older packages in Maven Central are more likely to encounter dependency resolution issues compared to newer ones. A widespread cause that was identified is the reliance on repositories without Transport Layer Security (TLS). Through this research, we highlight the prevalent issues within the Maven Central ecosystem and also offer insights into common causes of dependency resolution failures. We advocate for uploading new versions of libraries to multiple repositories to mitigate these issues. This study reviews the current state of Maven Central and extends some of the findings to other package management systems, contributing to a broader discourse on software longevity and dependency management.","Maven Central; Dependency resolution; Software longevity","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:7ed823a0-5a2c-4439-8fd0-60e02235f24e","http://resolver.tudelft.nl/uuid:7ed823a0-5a2c-4439-8fd0-60e02235f24e","Evaluating differential privacy on language processing federated learning","Van Opstal, Quinten (TU Delft Electrical Engineering, Mathematics and Computer Science)","Huang, J. (mentor); Chen, Lydia Y. (mentor); Zuniga, Marco (graduation committee); Delft University of Technology (degree granting institution)","2024","Federated learning provides a lot of opportunities, especially with the built-in privacy considerations. There is however one attack that might compromise the utility of federated learning: backdoor attacks [14]. There are already some existing defenses, like flame [13] but they are computationally expensive [14]. This paper evaluates a version of differential privacy, where the Gaussian noise added to the aggravated model of the clipped updates is smaller than usually. This is often referred to as weak differential privacy or weakDP. This paper evaluates weakDP with different parameters to find if weakDP can be used as a defense for a language processing federated learning classifier against a backdoor attack.","Federated learning; Differential Privacy; Non-iid","en","bachelor thesis","","","","","","A link to the associated github project. - https://github.com/QuintenVanOpstal/OOD_Federated_Learning.git","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:83d77bcf-8730-4165-8ea2-51da483a107f","http://resolver.tudelft.nl/uuid:83d77bcf-8730-4165-8ea2-51da483a107f","Learning Reduced-Order Mappings between Functions: An Investigation of Suitable Inputs and Outputs","Bakker, Bo (TU Delft Electrical Engineering, Mathematics and Computer Science)","Naderibeni, M. (mentor); Tax, D.M.J. (mentor); Tömen, N. (graduation committee); Delft University of Technology (degree granting institution)","2024","Data-driven approaches are a promising new addition to the list of available strategies for solving Partial Differential Equations (PDEs). One such approach, the Principal Component Analysis-based Neural Network PDE solver, can be used to learn a mapping between two function spaces, corresponding to a PDE. However, the practical limitations of this approach are unclear. This paper seeks to investigate for which types of inputs and outputs this type of solver gives useful results. Using a dataset with inputs sampled from Gaussian Random Fields with different parameters, and outputs for Poisson's equation and the Heat equation, obtained by using a Finite Element solver, neural networks are trained, and their performance is evaluated. The method performs adequately for the chosen inputs, and patterns are found in the resulting error, which differ for each set of input parameters. Thus, for these equations, it seems that this method performs differently for different input distributions, but further research is necessary to investigate if these patterns will hold for other equations.","Partial Differential Equations; Machine Learning; Gaussian Random Fields","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:172f4461-3474-4357-a118-b0837c0a068e","http://resolver.tudelft.nl/uuid:172f4461-3474-4357-a118-b0837c0a068e","Learning Reduced Order Mappings of Navier-Stokes: An Investigation of Generalization on the Viscosity Parameter","Kiste, Amund (TU Delft Electrical Engineering, Mathematics and Computer Science)","Tax, D.M.J. (mentor); Naderibeni, M. (mentor); Tömen, N. (graduation committee); Delft University of Technology (degree granting institution)","2024","Solving Partial Differential Equations (PDEs) in engineering such as Navier-Stokes is incredibly computationally expensive and complex. Without analytical solutions, numerical solutions can take ages to simulate at great expense. In order to reduce this cost, neural networks may be used to compute approximations of the solution for use during engineering processes. PCA-net is a neural network approach that reduces the dimensionality of the input and output data for PDEs in order to allow mapping from a high-dimensional input and output function with a fully connected neural network through the use of Principal Component Analysis (PCA). In this paper, PCA-net is applied to Navier-Stokes with varying viscosities to test the generalization of PCA-net on viscosity parameters. Training is done on four discrete viscosities, while testing is done on continuous viscosities, extrapolating and interpolating around the training set. Results shows good performance on low viscosities, both with interpolation and extrapolation. Mid-to-high viscosity interpolation shows lesser performance, with high viscosity extrapolation diverging to great error. Omitting high viscosities, performance over varying viscosities is close to that shown by previous research.","Principal Component Analysis (PCA); Neural Networks; Partial Differential Equations solver; Navier-Stokes; Reduced order modelling; Reduced Basis","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:f1041916-a81d-4b26-9639-623adb97efe6","http://resolver.tudelft.nl/uuid:f1041916-a81d-4b26-9639-623adb97efe6","Fragmenting Genome Sequences by Coding Regions to Improve Performance of the AmpliDiff Algorithm for Large Genomes","Karskens, Samuel (TU Delft Electrical Engineering, Mathematics and Computer Science)","Baaijens, J.A. (mentor); van Bemmelen, J. (mentor); Raman, C.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Abundance estimation with the use of environmental samples has been used during the SARS-CoV-2 pandemic to identify the abundances of different lineages. AmpliDiff, an algorithm that tries to find parts of DNA that can differentiate between different input genomes was used on a SARS-CoV-2 dataset to find these amplicons. The AmpliDiff algorithm was able to run on the SARS-CoV-2 set but seemed infeasible for datasets that contain larger or more complex genomes because of the computational requirements and runtime. We introduce a new pre-processing strategy based on selecting the most differentiable coding regions and show the modifications done to AmpliDiff to make AmpliDiff work following this new method. Based on the results we conclude that the approach is promising but still requires more research to be used optimally.","AmpliDiff; Amplicon; Abundance; Scalability","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:433be09a-c741-421a-9b14-2929f2318d62","http://resolver.tudelft.nl/uuid:433be09a-c741-421a-9b14-2929f2318d62","Procedural Tree Generation: How to efficiently predict branching structures from foliage?","Taklimi, Sam (TU Delft Electrical Engineering, Mathematics and Computer Science)","Eisemann, E. (mentor); Kellnhofer, P. (mentor); Uzolas, L. (mentor); Reinders, M.J.T. (graduation committee); Delft University of Technology (degree granting institution)","2024","The objective of this project is to train a model that transforms a tree with its foliage into only its branch structure. This is achieved by employing machine-learning techniques, specifically Generative Adverserial Networks (GANs). By utilizing the proposed method, a predictive model is built that automatically minimizes its own error function through a comparison of a set of input and ground-truth tree images, which are tree images with and without leaves, respectively. The adoption of GANs has shown promising results, both visually and metrically.","Computer Graphics; Generative Adverserial Networks (GANs); Image to Image transformation; Convolutional Neural Networks (CNNs)","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:f9deb2bb-215e-4a87-93cf-5a4b223403fb","http://resolver.tudelft.nl/uuid:f9deb2bb-215e-4a87-93cf-5a4b223403fb","Can we extract a relevant, available, and self-contained core of the Maven ecosystem?: Extracting the pillars of the community, and their dependencies.","van der Schoot, Mathijs (TU Delft Electrical Engineering, Mathematics and Computer Science)","Proksch, S. (mentor); Poulsen, C.B. (graduation committee); Delft University of Technology (degree granting institution)","2024","The Maven ecosystem, with an emphasis on Maven Central, contains a plethora of toy-projects. This paper addresses this problem by formulating a core containing the pillars of the Maven ecosystem, such that it can be exploited for research concerning li- brary quality. The construction of said core is done by analyzing the availability, relevance and depen- dencies of packages in the Maven ecosystem. It involves answering questions regarding the distri- bution of library usages, the dependencies of popu- lar libraries and the effect of a usage threshold fil- tering mechanism. We found the popular libraries to be utilized to an incredible extend, while their less popular counterparts are seldom, if ever, used. Delving into the creation of a core reveals its non- trivial nature, requiring intricate knowledge of the Maven dependency mechanism and its accompany- ing tools to construct. This paper explores the com- plexities, nuances and considerations involved.","Maven; Dependency Graph; Data analysis","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:040a1a1f-ad4f-40a4-a714-1cfd1916a77a","http://resolver.tudelft.nl/uuid:040a1a1f-ad4f-40a4-a714-1cfd1916a77a","What are the types of projects that Scratch users create?: How do different types of features relate to the project type?","Marczuk, Wojciech (TU Delft Electrical Engineering, Mathematics and Computer Science)","Pera, M.S. (mentor); Aivaloglou, E.A. (mentor); Martinez, Jorge (graduation committee); Delft University of Technology (degree granting institution)","2024","Scratch is a block-based programming language. It is designed to be simple and syntax error avoidant. This makes Scratch an accessible platform for cultivating coding skills. Many young learners are taught about different programming skills using various project types as examples. For instance, games are used as an engagement tool, and various games can motivate new learners to make their own. This influx of new published projects are manually classified into different types by using tags in the project descriptions. However, this manual classification only happens when the user adds the appropriate tags. This calls for an extension of that feature, which could help classify all projects published on the Scratch website. This has the goal of improving the browsing process, especially for new projects. To address this gap, in this initial iteration we leverage the fact that there are likely similarities, or even various project type defining features that would help improve the accuracy of classification through machine learning. Filling this gap also opens the possibility of automatic classification, depending on the accuracy of the results. Within this study, various machine learning models were tested with quantifiable project features as input data. The accuracy scores were compared to draw conclusions on how well various features extracted from Scratch projects performed for classification.","Scratch; Machine Learning; Classifciation","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:588a0a1a-5193-4371-9f14-88ae65cbfb6b","http://resolver.tudelft.nl/uuid:588a0a1a-5193-4371-9f14-88ae65cbfb6b","Data Driven Approximations Of PDEs: On Robustness of Reduced Order Mappings between Function Spaces Against Noise","Lacombe, Pablo (TU Delft Electrical Engineering, Mathematics and Computer Science)","Tax, D.M.J. (mentor); Naderibeni, M. (mentor); Tömen, N. (graduation committee); Delft University of Technology (degree granting institution)","2024","This paper presents a comprehensive exploration of a novel method combining Principal Component Analysis (PCA) and Neural Networks (NN) to efficiently solve Partial Differential Equations (PDEs), a fundamental challenge in modeling a wide range of real-world phenomena. Our research extends the work of Bhattacharya et al. by focusing on PCA for effective dimensionality reduction and utilizing NN for mapping in the reduced dimension. This approach addresses the significant computational challenges and inaccuracies often encountered with classical numerical techniques in solving PDEs.
We specifically investigate the still-water equation, employing our PCA-NN method to learn a reduced order mapping of PDE solutions and evaluate its robustness in diverse noisy environments. Our findings reveal a notable relationship between noise intensity and error, indicating a linear trend for Gaussian and Salt and Pepper noise, and an exponential trend for Uniform noise. Furthermore, this study uncovers a critical weakness of the model in predicting points with a high rate of change.
Overall, our research significantly contributes to understanding the practical applicability and limitations of PCA-NN methods in real-world, noisy settings, offering valuable insights for future applications in this domain.","Partial Differential Equations; Machine Learning (ML); Principal Component Analysis (PCA); Neural Network","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:13b5cb04-fdd8-4afe-90f2-0c02dfd5cbfc","http://resolver.tudelft.nl/uuid:13b5cb04-fdd8-4afe-90f2-0c02dfd5cbfc","Procedural Tree Generation: Inverse Modelling of 2D Trees using Graph Neural Networks","Mozafari, Erfan (TU Delft Electrical Engineering, Mathematics and Computer Science)","Eisemann, E. (mentor); Kellnhofer, P. (mentor); Delft University of Technology (degree granting institution)","2024","The most established and widely used methods for analysing tree images for tasks such as geometry analysis, segmentation and classification often rely on pixels. In this paper, the applicability of analyzing tree geometry based on a graph representation rather than a pixel-based approach is pursued. To do so, 2D renders of different species of trees are converted to spatial graph structures capturing significant points on the tree skeleton. Two independent Graph Convolutional Network algorithms which learn node (coordinate) features are then applied on the obtained dataset to assess the reliability of graph based analysis. The first experiment explores a GCN for assigning correct species labels to the skeleton graph of the original tree image, demonstrating the association between geometry and tree metadata. The second experiment, an unsupervised representation learning, is conducted by using Graph Autoencoders to obtain an embedding for each skeleton graph which can be used to reconstruct partially the same graph, demonstrating the association between GCE latent representation and geometry. Promising results were found in both cases, reinforcing the reliability of the original proposition to rely on geometry as well as pixels for tree analysis tasks.","","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:76dadd25-3c09-4802-b473-944616360558","http://resolver.tudelft.nl/uuid:76dadd25-3c09-4802-b473-944616360558","Prevalence of non-monotonicity in learning curves","Gafton, Dinu (TU Delft Electrical Engineering, Mathematics and Computer Science)","Viering, T.J. (mentor); Turan, O.T. (mentor); Hung, H.S. (graduation committee); Delft University of Technology (degree granting institution)","2024","Learning curves are useful to determine the amount of data needed for a certain performance. The conventional belief is that increasing the amount of data improves performance. However, recent work challenges this assumption, and shows nonmonotonic behaviors of certain learners on certain problems. This paper presents a new approach for detecting non-monotonicity in empirical learning curves. This method monitors the degree of monotonicity violation on non-monotonic intervals, using the performance difference. In addition, the accuracy of the algorithm is being assessed through a series of diverse experiments. The proposed algorithm is applied to a subset of the extensive Learning Curve Database (LCDB). The results indicate an experimental accuracy of 95.5% in identifying non-monotonicity within real learning curves. Importantly, the metric demonstrated its ability to distinguish genuine non-monotonic trends from minor fluctuations attributed to measurement errors.","Learning curve; non-monotonicity; LCDB","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:2c7d3bcf-e4f3-48e3-a418-ffb0351958b7","http://resolver.tudelft.nl/uuid:2c7d3bcf-e4f3-48e3-a418-ffb0351958b7","The Hotel—Homeless Segment: The Neighborhood","Stergiou, Maria (TU Delft Architecture and the Built Environment; The Berlage Center for Advanced Studies in Architecture and Urban Design)","Frausto, S.E. (mentor); Bouše, P. (mentor); Groothuijse, B. (mentor); Delft University of Technology (degree granting institution)","2024","The Neighborhood is a homeless hotel segment that invests in children’s better future. It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Homeless Segment Propositions:
1. The Homeless segment addresses homelessness as a generational issue.
2. The Homeless segment is a walkable neighborhood across the skyscraper.
3. The Homeless segment is a home before a homeless family can get their home.
4. The Homeless segment normalizes the accommodation of homeless families in the skyscraper hotel.
5. The Homeless segment encourages trust in welfare and personal development.","Hotel; New York City; Skyscraper; Homelessness; Children","en","master thesis","","","","","","","","","","","","The Berlage Post-MSc in Architecture and Urban Design","",""
"uuid:9d289479-7faf-4e20-a846-fefdf92c2183","http://resolver.tudelft.nl/uuid:9d289479-7faf-4e20-a846-fefdf92c2183","The Hotel-The Sailors' Boarding House: Navy Lodge Manhattan","Charalambous, Nicolaos (TU Delft Architecture and the Built Environment; The Berlage Center for Advanced Studies in Architecture and Urban Design)","Frausto, S.E. (mentor); Bouše, P. (mentor); Groothuijse, B. (mentor); Delft University of Technology (degree granting institution)","2024","Navy Lodge Manhattan is a Sailors' Boarding House segment that refreshes enlisted sailors. It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
The Sailors' Boarding House Segment Propositions:
1. The growing popularity of the annual New York Fleet Week and other major events contributes to the vital presence of sailors in the city.
2. A US. Navy–operated retreat in Midtown Manhattan relieves sailors from the difficulty of finding affordable accommodations for both short and long-term stays.
3. The Sailors’ Boarding House segment provides a gender-integrated home for male and female sailors smoothing the transition from duty to leave.
4. The presence of the sailors in the rhythm of the bustling hotel and the temporary exposure to other guests forms a mutually instructive encounter between them.
5. The Sailors’ Boarding House segment validates the United States Navy as a thriving organization that cherishes its personnel and the civilians it serves, and encourages recruitment.
Staphylococcus aureus and Pseudomonas aeruginosa: BEP Report","van der Poel, Jenneke (TU Delft Electrical Engineering, Mathematics and Computer Science)","Idema, T. (mentor); Dubbeldam, J.L.A. (mentor); Zwanikken, J.W. (graduation committee); Gijswijt, Dion (graduation committee); Delft University of Technology (degree granting institution)","2024","Staphylococcus aureus and Pseudomonas aeruginosa are two species of bacteria that are involved in numerous conditions, including lung infections and chronic wound infections. The aim of this project was to study the short-term interactions that occur when P. aeruginosa first encounters an established S. aureus colony, which it then seeks to break apart whilst mixing with S. aureus. Limoli et al. have studied these interactions using experiments, and have thus identified several key aspects involved in these interactions, such as the mechanisms that P. aeruginosa employs to approach the S. aureus colony. The means by which we intended to study interactions between S. aureus and P. aeruginosa is a model that was made by previous members of the Idema group and that was based on the experiments by Limoli et al. In this report, we discuss this model and the biological background relevant to it. We also document the problems that we encountered while trying to run simulations using an existing implementation of this model.","bacteria; modelling; simulation","en","bachelor thesis","","","","","","","","","","","","Applied Mathematics","",""
"uuid:1fd21181-441a-45b4-aed8-5259044af7af","http://resolver.tudelft.nl/uuid:1fd21181-441a-45b4-aed8-5259044af7af","The Hotel-Casino Segment: One Casino","Moreau, Eliott (TU Delft Architecture and the Built Environment; The Berlage Center for Advanced Studies in Architecture and Urban Design)","Frausto, S.E. (mentor); Bouse, Pavel (mentor); Groothuijse, B. (mentor); Delft University of Technology (degree granting institution)","2024","One Casino is a casino hotel segment where gamblers are dealt a good time. It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Casino Segment Propositions:
1. The Casino segment caters to a diverse gambling audience, including culturally indifferent residents and visitors, offering an alternative source of amusement tailored to their preferences in the vibrant setting of New York City.
2. Reflecting the city’s frenetic energy, the lower floors of the skyscraper are exclusively dedicated to the casino, operating continuously around the clock.
3. The Casino segment recreates the excitement of gaming in a dynamic manner, maintaining rigorous surveillance and operational efficiency within the skyscraper’s confined space.
4. Instead of offering accommodations, the Casino segment arranges rooms from other segments to accommodate specific high-spending guests.
5. The Casino plays a crucial role in bolstering significant revenue for the hotel, the city, and the state by collecting a 30 percent gambling tax and creating numerous job opportunities.
It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Love Segment Propositions:
1. The Love segment offers a safe haven for sex workers, providing stability amidst the challenges of the city’s sex-work landscape.
2. Centrally located, the Love segment offers a balanced, secure environment, avoiding unsafe streets while fostering chance encounters among guests.
3. A regulated floor empowers sex workers, offering controlled and exciting experiences, along with long-term living options, making it a transformative establishment.
4. Located in One Hotel’s heart, the Love segment guarantees safety, separate from neighbors, yet connects sex workers to society through sky lobby amenities.
5. The Love segment challenges stigmas, offering larger, less discreet spaces than historically unhygienic tenements and illegal massage parlors,and thereby redefining perceptions of sex work.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Wellness Spa propositions:
1. Establishing an unadorned sanctuary in the skyscraper and blending artificial with natural rejuvenation offers an escape from the city’s ornate mundanity.
2. Nestled above the slit between the two parts of the skyscraper, the Wellness Spa segment is veiled in spring garden mist, blurring its form into a tranquil haven.
3. Guests wander through aquatic gardens, in parallel with the plumbing system, discovering a journey of holistic well-being.
4. The Wellness Spa segment converts the skyscraper’s communal water system into a hydrotherapy oasis and boosts amenities and financial viability through collaboration with neighboring hotels.
5. The Wellness Spa segment, revealing its mechanical core, shows serene spaces that counter urban extravagance.","Hotel; New York City; skyscraper; Wellness Spa","en","master thesis","","","","","","http://thehotel.theberlage.nl","","","","","","The Berlage Post-MSc in Architecture and Urban Design","ARB301",""
"uuid:4751a4fa-648a-4bce-a08f-54c62649c186","http://resolver.tudelft.nl/uuid:4751a4fa-648a-4bce-a08f-54c62649c186","The Hotel–Resort Segment: City Resort","Nuño de Buen, Ana (TU Delft Architecture and the Built Environment; The Berlage Center for Advanced Studies in Architecture and Urban Design)","Frausto, S.E. (mentor); Bouše, P. (mentor); Groothuijse, B. (mentor); Delft University of Technology (degree granting institution)","2024","The City Resort is a resort hotel segment that indulges vacationers in a manicured paradise. It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective Propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Resort Segment Propositions:
1. The Resort segment is a remedy for today’s over-worked society.
2. The Resort segment mediates between the guest’s desire for both isolation and social life.
3. The Resort segment is a vertical meandering through sequences of delays, destinations, and spatial transitions characterized by different levels of exposure.
4. The Resort segment is part of a collection of amenities shared with other leisure-oriented segments.
5. The Resort segment offers a new lens through which to view the city.","Hotel; New York City; Skyscraper; Resort","en","master thesis","","","","","","","","","","","","The Berlage Post-MSc in Architecture and Urban Design","ARB301",""
"uuid:0a3e35a5-1526-461e-92b9-9879b32aa954","http://resolver.tudelft.nl/uuid:0a3e35a5-1526-461e-92b9-9879b32aa954","The Hotel—Boutique Segment: Eminence Trade","Slangen, Lenneke (TU Delft Architecture and the Built Environment; The Berlage Center for Advanced Studies in Architecture and Urban Design)","Frausto, S.E. (mentor); Bouse, Pavel (mentor); Groothuijse, B. (mentor); Delft University of Technology (degree granting institution)","2024","Eminence Trade is a boutique hotel segment that elevates aspirants’ real life and online presence. It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Boutique Segment Propositions:
1. Eminence Trade is accessible to aspirants of all incomes and backgrounds.
2. Eminence Trade offers a place of comfort, adjacency, ambition, eminence, and equality.
3. Eminence Trade, the luxurious flagship of One Hotel’s brand, differentiates a plethora of private, public, and partnership amenities to ensure its leading-edge business model.
4. Eminence Trade, as a place of sublimity and exclusivity, offers temporal and unilateral types of use of accommodation and amenities within One Hotel.
5. In a city of aspiration, Eminence Trade signifies eminence but does not equate
elevating above others.","Hotel; New York City; Skyscraper; Boutique; Eminence; Exclusivity; Segregation","en","master thesis","","","","","","http://thehotel.theberlage.nl","","","","","","The Berlage Post-MSc in Architecture and Urban Design","ARB301",""
"uuid:a45a7c9a-0132-4b45-aeff-8aabfc40d63f","http://resolver.tudelft.nl/uuid:a45a7c9a-0132-4b45-aeff-8aabfc40d63f","The Hotel—Residential Segment: Almost Home","Chen, Chaomin (TU Delft Architecture and the Built Environment; The Berlage Center for Advanced Studies in Architecture and Urban Design)","Frausto, S.E. (mentor); Bouše, P. (mentor); Groothuijse, B. (mentor); Riedijk, M. (mentor); Delft University of Technology (degree granting institution)","2024","“Almost Home” is a residential hotel segment that is (almost) home to precariats on the move. It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Residential segment proposition:
1. Purposeful precariats in New York City reject traditional senses of home.
2. Only in the middle of the skyscraper can precariats find seclusion and connection to Manhattan.
3. A residential hotel encourages its guests to consider the value of a life unbound from place.
4. By sharing with other long-term guests of One Hotel, the Residential segment asks the guests to consider either staying alone “at home,” or together “at home.”
5. A home is a space where you have to do chores.
Marriott Metropolitan is a chain hotel segment that entices business travelers to extend their journey. It is part of The Hotel, a collective project that studies the hotel, both as a building type and as a place of hospitality, through a collection of fourteen individual contributions inside one skyscraper. The project imagines hospitality as a realm of exchange that condenses the diversity of the city through an assortment of guests, staff, and the broader public.
The hotel is a function of temporality and hospitality. The study questions the requirements for an architecture of hospitality to welcome, host, and entertain. As an architecture of temporality—an architecture that is dynamic and ever-changing, embodying a sense of transience and constant activity—the hotel allows for experimentation, while anticipating adaptation to meet the changing demands of its temporary residents. The hotel, as type, is understood beyond its curated front. It is, instead, a place of anonymity and exchange, of served and serving, a place characterized by short stays in a lasting structure.
The skyscraper, as a formal and monumental object, appears to contrast the hotel’s temporality. In its autonomy, the skyscraper is a landmark in the skyline. Located in Midtown Manhattan—on the former site of Hotel Pennsylvania and adjacent to Penn Station—this project is a reflection on the metropolis of New York City.
The Hotel consists of the design of the skyscraper as landmark—The Metropolitan—and the hotel as tenant—One Hotel.
Collective propositions:
1. The Hotel embraces the frenetic energy of New York City while opposing its outward expansion.
2. The Metropolitan will outlast One Hotel.
3. One Hotel accommodates fourteen types of guests, and its staff.
4. One Hotel shares accommodation, amenities, systems, and services with a 24/7 cycle.
5. The Hotel sets a standard for an architecture of hospitality.
Chain Segment Propositions:
1. As the most expensive travel destination, New York City is witnessing a resurgence in business travel and its price soar.
2. The Chain segment is located between Sky Lobby 1 and 2 to take advantage of different shareable amenities.
3. Business travelers can book or upgrade different rooms depending on the duration of their stay.
4. Brand-based membership systems provide customer loyalty and the Chain segment brings continuous business to One Hotel.
5. The Chain segment balances standardization with specialization.","Hotel; New York City; Skyscraper; Chain Hotel; Business Travel","en","master thesis","","","","","","http://thehotel.theberlage.nl","","","","","","The Berlage Post-MSc in Architecture and Urban Design","ARB301",""
"uuid:60f7bc45-2550-4e03-a570-ae2a4bb01b14","http://resolver.tudelft.nl/uuid:60f7bc45-2550-4e03-a570-ae2a4bb01b14","Analysis on the Vulnerability of Multi-Server Federated Learning Against Model Poisoning Attacks","Nenovski, Lazar (TU Delft Electrical Engineering, Mathematics and Computer Science)","Huang, J. (mentor); Chen, Lydia Y. (mentor); Zuniga, Marco (graduation committee); Delft University of Technology (degree granting institution)","2024","Abstract— Federated Learning (FL) makes it possible for a network of clients to jointly train a machine learning model, while also keeping the training data private. There are several approaches when designing a FL network and while most existing research is focused on a single-server design, new and promising variations are arising that make use of multiple servers, witch have the benefit of speeding up the training process. Unfortunately single-server FL networks are prone to model poisoning attacks by malicious participants, that aim to reduce the accuracy of the trained model. This work showcases the inherent resilience of the multi-server design against existing state-of-the-art attacks tailored around single-server FL, as well as propose two novel attacks that exploits multi-server topology in order to reduce the required knowledge an adversary needs to obtain to carry out the attack, while still remaining effective. Main findings are as follows: In the event that the malicious party has compromised the entire network, existing single-server attacks are sufficient to completely prevent a model from training. If they are limited to knowledge available only within the local reach of their compromised clients, the effect is minimized to where the attacks might get mitigated without any defences being necessary. However in such cases a correlation can be observed between the location of the compromised clients and the effectiveness of an attack. The novel attacks proposed in this paper exploit this relation in order to remain sufficiently effective while requiring only the same amount of data necessary for the multi-server algorithm to function.","Federated Learning; Multi-server FL; Untargeted Attack","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:10b33331-51a0-4f0e-8314-fa041eff09e4","http://resolver.tudelft.nl/uuid:10b33331-51a0-4f0e-8314-fa041eff09e4","The effect on lift & drag of an under-wing fireworks launch platform placed near the wingtip","De Zutter, Gajtan (TU Delft Aerospace Engineering)","Melkert, J.A. (mentor); Delft University of Technology (degree granting institution)","2024","This study investigates the effect on the principal aerodynamic forces caused by home-built under-wing attachments excluding possible consequences on the aircraft’s control and manoeuvrability. Many other types of wing attachment have already been used and investigated of time. However, none of these attachments match exactly the attachment under investigation in this study.
For aerial display purposes, one of the team members of the Whiskey Formation Team created an under-wing firework launch platform attached to the tie-down points of the aircraft. These tie-down points are fixed to the quarter chord wing spar at about 90% of the half wing span near the wingtip. The launch platforms themselves protrude about a quarter of their own length in front of the wing’s leading edge. The remaining part is attached flush with the wing’s lower skin.
After installing the attachments on the aircraft’s wing, the creator took it upon himself to do some trial high speed taxi runs followed by a standard take-off. A circuit around the field and a full stop landing completed his trial run during which no adverse effects on the aircraft handling or flight safety could be detected.
Next, on the first trial flight as a formation with the launch platforms attached, the team leader claimed he experienced a slight performance increase. Earlier lift-off and sharper turns were among the examples of this performance increase he gave. No claims on the aircraft’s fuel consumption, cruising speed or power-off gliding performance were made. This was not investigated and is deemed not to be relevant to the aerial display.
This report investigates these claims by modelling the aircraft for computational flow simulations, with and without the platforms attached, for both take-off and high G-load turns. For the take-off condition a runway surface is modelled at a wheels-height distance from the aircraft’s wing. Realistic speeds of 50 and 60 knots respectively are chosen together with 10 degrees of geometrical pitch.
The result of these simulations was then validated in real life circumstances to eliminate possible adverse results due to modelling error of the real life aircraft. A number of comparative test flights, 5 in total with 6 take-offs per flight, were performed registering weight and take-off speed for a trimmed stick-free configuration. The results obtained from these test flights are likely to confirm the results obtained from the simulations. For the simulations, a larger lift and lower drag force are noted for the configuration with the launch platform attached for The steep turn case. For the take-off case a drag increase was noted. In the real life test this could be confirmed by the almost identical take-off velocities even though this falls well within the error margin of the experimental setup. The gain in lift, most pronounced for the steep turn case, comes from the blocking of the spanwise flow by the launch platforms hereby likely reducing the lift-induced drag caused by the wing tip vortex. The total drag of the modelled wing is reduced for the steep turn case even though the launch platforms contribute to the friction drag. Moreover, the model’s lift-to-drag ratio, a common measure of aircraft’s performance, is increased.
It can therefore be concluded that for the investigated cases indeed a small effect of the launch platforms on the aircraft’s performance can be found though it is deemed unlikely that this difference is be noticeable. Real life tests only show little promise since the error margin occludes the effects on performance. For flight display purposes a different meaning of the word ’performance’ is meant. The lift force is considered much more important than the drag force, even though the drag force is reduced too. Therefore it can be concluded that the installation of the launch platforms does not adversely affect the aircraft’s performance parameters such as lift and drag. Moreover, it is plausible that they do improve the aircraft’s performance parameters and do improve the performance of the aircraft for aerial display purposes.","","en","master thesis","","","","","","","","","","","","Applied Physics","",""
"uuid:f90541b8-232b-47be-8470-d79b273279ae","http://resolver.tudelft.nl/uuid:f90541b8-232b-47be-8470-d79b273279ae","Exploring the Impact of Single-Character Attacks in Federated Learning Language Classification: Introducing the Novel Single-Character Strike","van der Meulen, Jan (TU Delft Electrical Engineering, Mathematics and Computer Science)","Chen, Lydia Y. (mentor); Huang, J. (mentor); Zuniga, Marco (graduation committee); Delft University of Technology (degree granting institution)","2024","Federated learning (FL) is a privacy preserving machine learning approach which allows a machine learning model to be trained in a distributed fashion without ever sharing user data. Due to the large amount of valuable text and voice data stored on end-user devices, this approach works particularly well for natural language processing (NLP) tasks. Due to many applications making use of the algorithm and increasing interest in academics, ensuring security is essential. Current backdoor attacks in NLP tasks are still unable to evade some defence mechanisms. Therefore, we propose a novel attack, the single-character strike to address this research gap. Consequently, the following research question is posed: What are the properties of the single-character strike in a language classification task? By experimental analysis the following properties are discovered: the single-character strike is undetectable against five state-of-the-art defences, has low impact on the global model accuracy, trains slower than similar attacks, relies on characters on the edge of the distribution to function, is robust within the global model, and performs best when close to convergence and with more adversarial clients. Emphasizing its imperceptibility and persistence, the attack maintains a 70\% backdoor accuracy after a thousand iterations without training and remains undetectable against: (Multi-)Krum, RFA, Norm Clipping and Weak Differential Privacy. By providing insight into the effective single-character strike, this paper adds to the growing body of work that questions whether federated learning can be secure against backdoor attacks.","federated learning; natural language processing; backdoor attack; single-character-strike; security","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:8fa9a391-46e0-41bc-abde-fb858409ca7f","http://resolver.tudelft.nl/uuid:8fa9a391-46e0-41bc-abde-fb858409ca7f","Continuous Chromatography of Biopharmaceuticals: Next Generation Process Development","Picanço Castanheira Da Silva, T. (TU Delft BT/Bioprocess Engineering)","Ottens, M. (promotor); Eppink, M. (promotor); Delft University of Technology (degree granting institution)","2024","The biopharmaceutical industry is moving from a batch to a continuous mode of manufacturing. This shift promises to reduce costs and manufacturing footprint while improving productivity and consistency of the product. This thesis implements miniaturized and automated high-throughput screening techniques alongside a mathematical chromatography model for the development of an integrated continuous chromatography process. The model is used for in-silico optimization of a capture and polishing step of a monoclonal antibody (mAb). The optimization focusses on chromatographic processes that would have to deal with higher titer solutions.
The transition to Integrated Continuous Biomanufacturing (ICB) is welcomed by industry and regulatory agencies, which are working together to accomplish this shift. Process development plays a crucial role in defining new processes or adapting existing processes to different modes of operation. High-Throughput Process Development (HTPD) has been used in the biopharmaceutical industry to accelerate and reduce costs of process development, by using miniaturized assays and performing computer-aided studies. However, the industry experiences gaps and sees opportunities for improvement in the HTPD tools that can help the transition to ICB. These gaps, together with a state-of-the-art of HTPD for ICB are presented in Chapter 2. Experts in the field identified microfluidics and modeling to be the most promising technologies to fill in the gaps in process development for ICB.
Subsequently, an overview on the state-of-the-art of automation and miniaturization for biopharmaceutical process development is given in Chapter 3. The focus is on different degrees of miniaturization and automation of the technologies for process development, for both Upstream and Downstream processing (USP and DSP, respectively). Liquid-Handling Stations (LHS) are the epitome of automation for process development, and have seen great adoption for the past decades. Examples of the use of this tool for USP and DSP process development are provided. A greater emphasis is placed on the often overlooked microfluidics and how it can also be used as a screening tool, and a SWOT analysis on LHS and microfluidics as potential process development tools is provided.
Further comparison between HTS tools for chromatographic process development is needed, since process development efforts for chromatography mostly rely on LHS-based experiments. Three methodologies are selected for this comparison: LHS, microfluidics, and Eppendorf tubes (Chapter 4). To achieve this, protein equilibrium adsorption isotherms are determined with each of the aforementioned methodologies. The microfluidics chip produced in-house provides a platform for resin screening that achieves liquid and resin volume reductions of 15- and up-to 200-fold, respectively. Accurate resin volume determination is ensured with an image analysis software, and resin consumption is as high as 200 nl in the microfluidics system. After validating the HTS methodologies, a cost consideration study aims at fairly comparing the three methodologies for their chromatographic process development potential. Although at a lower Technology Readiness Level, microfluidics can be a viable alternative tool when the protein to be studied is very expensive or scarce (such as in early stages of process development), due to the high degree of miniaturization. Furthermore, it is discussed what would be the possible applications of the different methodologies in chromatographic process development.
The HTS methodologies developed paved the way for the implementation of a HTPD approach for the study and optimization of continuous chromatography (Chapters 5 and 6). A large database on the adsorption equilibrium isotherms of mAbs to different protein A (ProA) and Cation-Exchange (CEX) resins is generated from experiments with a LHS. This database is then used to further reduce resin candidates to be used in subsequent experiments. Four resin candidates are used to study the equilibrium adsorption isotherms of mAb to ProA ligands with a clarified cell culture supernatant (harvest). It is shown that pure mAb experiments reflect the same adsorption behavior as harvest experiments for all resin candidates, reducing the need to duplicate experiments in the future. The parameters determined are further used in a mechanistic Lumped Kinetic Model (LKM), used for the in-silico study of column chromatography (Chapter 5). The LKM uses a lumped overall mass transfer parameter that is linearly dependent on feed concentration, in line with mass transfer theory. The hybrid approach to HTPD emphasizes the importance of computational, experimental, and decision-making stages in chromatographic process development.
The LKM model described is further developed for the study of continuous chromatography. The continuous model is used for the in-silico optimization of a 3-Column Periodic Counter-current Chromatography (3C-PCC) capture and polishing step, for the purification of mAbs from high-titer solutions (Chapter 6). The model maximizes Productivity and Capacity Utilization (CU) keeping the yield high (99%) and having the flow rate and the percentage of breakthrough achieved in the interconnected phase as constraints. The shape of the breakthrough curve plays an important role in the optimization of continuous chromatography. The optimization results are validated for three different ProA resins, from which the best resin candidate is selected to continuously capture mAb from a harvest solution. The eluates of this operation are pooled and used as input for the continuous CEX step. The experimental results show very good agreement with model’s predictions (lower than 7% deviation) and the proposed methodology helps to develop and optimize a continuous chromatography process in a short amount of time.
In summary, this thesis presents the exciting journey of process development for continuous chromatography, from conceptualization and selection of screening techniques until the end result of performing an optimized continuous chromatographic step for the successful capture and polishing of a mAb.","","en","doctoral thesis","","978-94-6366-802-6","","","","","","2024-02-02","","","BT/Bioprocess Engineering","","",""
"uuid:accb70f0-6716-49fc-ab9d-bcc897f07e8e","http://resolver.tudelft.nl/uuid:accb70f0-6716-49fc-ab9d-bcc897f07e8e","Towards More Effective Querying of Medical Literature in Alexandria3K: How useful can Alexandria3K be for performing literature reviews","Verlooy, Bas (TU Delft Electrical Engineering, Mathematics and Computer Science)","Spinellis, D. (mentor); Gousios, Giorgos (mentor); Langendoen, K.G. (graduation committee); Delft University of Technology (degree granting institution)","2024","The Alexandria3K library, a versatile Python-based tool, has been expanded to include the integra- tion of the PubMed dataset, enriching its capabil- ities in the analysis of scientific papers. Origi- nally supporting major datasets like Crossref and US patents, and smaller yet significant datasets like ORCID. The addition of PubMed enables in-depth analysis of medical papers, with medical specific data and articles not yet in the Crossref dataset. This research focused on validating the integration of PubMed into Alexandria3K. To achieve this, two literature surveys were replicated using the com- plete PubMed dataset. The first survey involved querying different pathogens in the dataset for three regions. The results were comparable, although some articles were missed by Alexandria3K but two articles were also missed by the original sur- vey. The second survey revolved around software tools used in medical papers. Although fewer ar- ticles were found with Alexandria3K the ratio for most tools was still comparable. Although a thor- ough manual review of all articles could have fur- ther refined the reevaluation, time constraints pre- vented this step. These replicated surveys demon- strate Alexandria3K’s potential in conducting lit- erature surveys, underscoring the need for manual validation to complement its capabilities.","Alexandria3k; pubmed; biobliometric analysis","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:0734b9c6-888a-4e0d-a8b8-3f9c3c6dfc1e","http://resolver.tudelft.nl/uuid:0734b9c6-888a-4e0d-a8b8-3f9c3c6dfc1e","Finding your digital sibling: Grouping GitHub projects that share certain attributes based on interactions and activities","de Bruin, Rowan (TU Delft Electrical Engineering, Mathematics and Computer Science)","Proksch, S. (mentor); Huang, S. (mentor); Olkhovskaya, Julia (graduation committee); Delft University of Technology (degree granting institution)","2024","This study explores the feasibility of categorizing GitHub projects based on their interactions and activities, aiming to assist both researchers and practitioners in navigating the vast landscape of open-source software. Through experiments and analysis, key attributes contributing to project categorization are identified, paving the way for effective grouping of projects in terms of interactions and activities. Findings indicate distinct clusters among GitHub projects, highlighting the influence of interactions and activities on project categorization. The study underscores the importance of refining grouping algorithms and improving project categorization methods for future research. Future work could involve developing user-friendly tools to facilitate project discovery and exploring correlations between interaction related metrics and project development dynamics. Overall, this study contributes to advancing our understanding of project categorization on GitHub, facilitating more efficient knowledge sharing and collaboration within professional fields.","GitHub; Interactions; Activities; Software; Project grouping","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:fec41ae4-f1ac-4702-a703-57a81beedc0c","http://resolver.tudelft.nl/uuid:fec41ae4-f1ac-4702-a703-57a81beedc0c","A generative AI integration tool for managers: Preparing, dealing and thriving with the impact of AI","van Veen, Joep (TU Delft Industrial Design Engineering)","de Vos, Marina (mentor); Gu, Eric Heng (graduation committee); Delft University of Technology (degree granting institution)","2024","This graduation report presents a comprehensive approach to the identification of an opportunity in the rising technology and interests in generative AI. The report delivers a concept for a tool that is designed for managers. The tool is aimed at aiding in the integration of generative AI within teams. The project is grounded in a literature review, stakeholder interviews, a co-design session with students, a survey with stakeholders and validating. The literature review shows there is an expected rise in interests and demand for using the new technology of generative AI. The interviews with stakeholders shine light on the necessary means that are needed to integrate generative AI in the workplace. Some of these means are: more knowledge, more experience and a starting point. The co-design session brought new perspectives on solutions and opportunities that the tool could incorporate to be successful. The major breakthrough of the co-design session is the implementation of employee interaction. In the value survey it is shown that the managers do not want too much insights in their employee behavior and would prefer a personalized document of advice for implementation. At the end of the development stage the concept is shown to the target audience who give their option on how well it manages to fulfill its purpose. The responses are positive enough that only minor suggestions are given to improve the concept. The final concept tool offers multiple options to achieve the desired solution. Using the profile of the manager and of their employees, the tool provides personalized advice to enhance decision making and awareness of actions. In addition, the tool incorporates employee interaction, enabling team members to unknowingly contribute to the insights that further refine the advice that the manager gets. The tool does not only offer advice, it also offers training and educational components to further provide managers with the skills needed to navigate the fast changing landscape of generative AI integration. The report contributes by collecting and transforming valuable insights and translating that into written output which can be used in the future for development in the generative AI area. The paper also offers a concept for a practical tool designed to prepare, deal and thrive within the generative AI powered workplace. This concept can be used as a reference point for projects that aim to design a similar tool.","Artificial intelligence; Managers; Employee interaction; Transformation; Generative AI management,; Generative AI; Tool design; organizational change; Generative AI impact","en","master thesis","","","","","","","","","","","","Strategic Product Design","",""
"uuid:2ec66360-478e-4768-be95-044c2c015d4f","http://resolver.tudelft.nl/uuid:2ec66360-478e-4768-be95-044c2c015d4f","Schur Multipliers of Divided Differences and Multilinear Harmonic Analysis","Reimann, Jesse (TU Delft Electrical Engineering, Mathematics and Computer Science)","Caspers, M.P.T. (mentor); de Oliveira Filho, F.M. (graduation committee); Zegers, S.E. (graduation committee); Delft University of Technology (degree granting institution)","2024","It was first shown by D. Potapov and F. Sukochev in 2009 that Lipschitz functions are also operator-Lipschitz on Schatten class operators Sp, 1<p<∞, which is related to a conjecture by M. Krein. Their proof combined Schur multiplication, a generalisation of component-wise matrix multiplication, with the so-called first order divided difference of a function, an approximation of its derivative. Showing that the Schur multipier associated with a divided difference function is bounded relies on a so-called transference technique, the boundedness of certain Schur multipliers can be inferred from the boundedness of associated Fourier multipliers. Soon after, this boundedness result was extended by D. Potapov, A. Skripka, and F. Sukochev to multilinear Schur multipliers of divided differences of arbitrary order, i.e. approximations of higher derivatives.
In this thesis, we offer an alternative boundedness proof for bilinear Schur multipliers of second order divided differences, in which we use recent results of multilinear harmonic analysis towards a multilinear transference proof, as well as recently found sufficient conditions for the boundedness of linear Schur multipliers which cannot be studied by transference. These methods were not known at the time Potapov, Skripka, and Sukochev proved their result.
Moreover, we show that this new proof improves the growth of the bound on the norm of the considered Schur multiplier for p→∞ significantly. Finally, we give an outlook on further steps towards an alternative boundedness proof of multilinear Schur multipliers of divided differences of arbitrary order.
This thesis extends the existing method by leveraging a division of the state space into regions and inferring action distributions over these regions, rather than over the entire state space. We show that this can accelerate the policy search. We also show that the algorithm manages to recover if the division is unjustified. The division into regions can hence also be considered a form of prior knowledge of the policy with uncertainty. Finally, inference of the regions themselves is also explored and yields promising results.","Markov Decision Processes; Probabilistic Programming; Sequential Decison Making; Bayesian Inference; Machine Learning (ML); Artifical Intelligence; Reinforcement Learning (RL); Planning under Uncertainty; MDP","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:20899007-f811-4f36-a638-435fdfc07d08","http://resolver.tudelft.nl/uuid:20899007-f811-4f36-a638-435fdfc07d08","Transport inequality in the Netherlands: Exploring transport vulnerabilities and transport poverty risk","Wisse, Laurens (TU Delft Technology, Policy and Management)","Kroesen, M. (mentor); Oviedo-Trespalacios, O. (graduation committee); Delft University of Technology (degree granting institution)","2024","Political and societal attention on transport inequality, transport vulnerabilities and transport poverty risk has been increasing the last five years. The Dutch government has committed multiple large sums of resources to abate the issue, 120 million euros to cancel the increase in price of train tickets, 300 million to cancel the increase in price and preserve the provision of the regional public transit and 6 million to start a pilot of ‘innovative public transport’ in the Zeeland region. A review of the literature on transport poverty risk reveals that past studies analyze the concept using a limited number of pre-selected variables. For example, car ownership and residence area. This carries the risk for misinterpretation as an accurate representation can only be achieved by considering all relevant variables. Such a comprehensive analysis could allow policymakers to formulate tailor-made policies according to the specific problems and needs of certain groups in society. This study aims to include the entire complexity of the concept of transport poverty risk in the analysis. Relevant factors include affordability, accessibility and mobility. Then there are individual differences, and for every individual changing over time, between needs of participating in society and social life. This study aims to incorporate this comprehensive definition in a Latent Class Analysis approach to construct groups of individuals based on the MPN and ODiN national datasets. The different groups of individuals can be then used to indicate the effect of policies on transport inequality. Results show three groups that are most transport ‘fortunate’, with high income, high car ownership, high accessibility and the potential to use different travel modes. Results also show one group with substantial transport vulnerabilities due to higher car dependency, lower car ownership and lower household income. A policy thought experiment is established through the application of mobility policy packages of three political parties. Car policies that reduce costs per driven kilometer such as reduction in excise tax will increase transport inequality due to the three groups that are the most transport ‘fortunate’, which also have the highest car use. This study provides the scientific community with a comprehensive definition and conceptual model of transport poverty risk and for policymakers contributes a comprehensive understanding of transport inequality in the Netherlands. Future research needs to focus on identifying specific minority groups that are not or less captured in the national datasets. Transport problems are experiences by an individual, while transport inequality is represented by the differences in the extent of transport problems between certain individuals or groups. In this case, certain groups in the Netherlands. This calls for the need to differentiate the government levels at which transport inequality and transport problems are addressed. While this study presents the transport inequality at the national level, municipalities will be able to identify specific individuals and neighborhoods who are more prone to transport problems.","","en","master thesis","","","","","","","","2025-02-01","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:dde430e8-d0e0-4d63-9785-ed442e3574bd","http://resolver.tudelft.nl/uuid:dde430e8-d0e0-4d63-9785-ed442e3574bd","Use of LLMs to Improve Affiliation Disambiguation in Alexandria3k","Gupta, Dibyendu (TU Delft Electrical Engineering, Mathematics and Computer Science)","Spinellis, D. (mentor); Gousios, Giorgos (mentor); Langendoen, K.G. (graduation committee); Delft University of Technology (degree granting institution)","2024","The growth of academic publications, heterogeneity of datasets and the absence of a globally accepted organization identifier introduce the challenge of affiliation disambiguation in bibliographic databases. In this paper, we create a baseline using the currently implemented algorithm for author affiliation linkage in Alexandria3k by comparing it to the ground truth. We aim to explore the usage of LLMs (GPT-4) in the Alexandria3k environment to disambiguate author affiliations. The proposed approach extracts the research organization from textual affiliations provided by researchers through their published works and cross-references the organization across the Research Organization Registry. Our process shows promising results and a significant improvement on the existing algorithm in terms of matching rate and identification of multiple affiliations. We discuss the margin of error in LLM results, limitations of the ground truth, and suggest future research directions.","Affiliation Disambiguation; LLM; Alexandria3k; Ground Truth; GPT-4","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:a1873e38-fe64-4156-b64b-930b4cae9b88","http://resolver.tudelft.nl/uuid:a1873e38-fe64-4156-b64b-930b4cae9b88","Clustering Scratch projects by code complexity traits and project traits","Meeusen, Brent (TU Delft Electrical Engineering, Mathematics and Computer Science)","Aivaloglou, E.A. (mentor); Pera, M.S. (mentor); Martinez, Jorge (graduation committee); Delft University of Technology (degree granting institution)","2024","Scratch is a popular, visual programming language aimed at children, and is used by teachers and after school code clubs to teach their students about programming. Measuring whether they understand the underlying concepts, however, is a difficult task. In this research, we tried clustering Scratch projects by complexity to help students improve their programming skills. We did this by selecting an existing data set to extract features that indicate code complexity. Before, researchers attempted clustering on one metric that globalises the project’s complexity. Different researchers set out to measure the growth of the students by clustering the projects the students created.
With that in mind, we adopt a partition-based clustering algorithm to cluster the projects, as this method indicates outliers. We examine the quality of these clusters using the silhouette coefficient. We set up five experiments with different input vectors to make out the impact each input has on the clusters. We did not find a clear indication of the projects being clustered by the selected features. This could mean that Scratch projects are not suitable to measure a high-level understanding of programming concepts. Including the project name in the input vector had a negligible effect on the outcome of the experiments.","Computer Science; clustering; scratch","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:6db01376-931b-4eb2-a494-4eee0c55cde7","http://resolver.tudelft.nl/uuid:6db01376-931b-4eb2-a494-4eee0c55cde7","Finding your digital sibling: which other GitHub projects are similar to yours?: Finding similar repositories based on the available documentation","Turcu, Alexandru (TU Delft Electrical Engineering, Mathematics and Computer Science)","Proksch, S. (mentor); Huang, S. (mentor); Olkhovskaya, Julia (graduation committee); Delft University of Technology (degree granting institution)","2024","This paper aims to study the importance of considering the documentation side of GitHub repositories when assessing the similarity between two or more applications. Readme and Wiki files, along with Comments from the source files, are the dimensions proposed to be analyzed through our methodology and experiments. We propose a pipeline that first extracts text fragments from these dimensions and then applies Natural Language Processing techniques to further prepare our data for evaluation. To gather a similarity score, we first vectorize our processed data with TF-IDF and then use cosine distance to obtain the score. Combinations of the three dimensions, ranging from using only one dimension to using all of them, are considered throughout our study. Moreover, additional information has been extracted from the plain text, such as referenced URLs and License usage, the similarity of which was calculated using Jaccard distance. Two experiments were performed. The first one aims to observe the behavioral tendencies of our methodology applied to a small dataset, while the second one aims to validate our results. By evaluating them, we found sufficient data that supported our presented conclusion: documentation represents a valuable asset in gathering a pool of similar applications.","GitHub; Text Mining; Documentation","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:7ca6216f-2636-4c9c-85d3-f381b956870f","http://resolver.tudelft.nl/uuid:7ca6216f-2636-4c9c-85d3-f381b956870f","Procedural Tree Generation: Compressing 3D tree for faster rendering","Manda, Sebastian (TU Delft Electrical Engineering, Mathematics and Computer Science)","Eisemann, E. (mentor); Kellnhofer, P. (mentor); Uzolas, L. (mentor); Reinders, M.J.T. (graduation committee); Delft University of Technology (degree granting institution)","2024","Trees are essential components of both real and digital environments. Therefore, it is important to have 3D models of trees that are of high quality and computationally efficient. One way to achieve this is by compressing a high-quality model using billboard rendering, which involves partitioning the tree into multiple planes to produce a similar result to the original. Our study explores the compression of 3D models using an optimization loop and adapting billboard rendering techniques. We use computer vision primitives to render basic models, which we then optimize by adjusting the texture to resemble the original tree. The models consist of multiple upright planes that are rotated around the central vertical axis of the original tree. We use different optimization functions, such as L1 and L2 losses, to determine the best approach. We can improve the initial models by bounding the billboards and limiting their heights and widths to that of the trees. Additionally, we can use double-sided textures for the billboards to allow more flexibility for optimizing different species of trees. However, optimizing multiple tree types performs differently for each species, leading to improvements that only benefit certain trees in specific scenarios. Using quantitative metrics, we determined which models perform best and how similar they are to the original after training. We found that our compressed models generally resemble the original while having only a fraction of the original size.","Computer Graphics; 3D Model Compression; Rendering; Loss Optimization","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:ee36bc7a-da2a-47b2-91fd-2d428ad51c05","http://resolver.tudelft.nl/uuid:ee36bc7a-da2a-47b2-91fd-2d428ad51c05","Topic Classification of Publications: Identifying publication topics based on existing journals","Lim, Dayoung (TU Delft Electrical Engineering, Mathematics and Computer Science)","Spinellis, D. (mentor); Gousios, Giorgos (mentor); Langendoen, K.G. (graduation committee); Delft University of Technology (degree granting institution)","2024","Accurate topic classification is crucial in the scientific community when it comes to finding relevant journals. However, the efficiency and accuracy of topic classification of publications do not seem to be at its best performance, especially with the fast-paced rise in the quantity of research papers. Our research aims to address this problem by utilizing state-of-the-art (SOTA) methods. We chose the 'April 2022 Crossref' data set for the research, as Alexandria3k, the tool utilized for querying on the open data set, is tested on the same data. We stratified 50,000 data that have title, abstract, and work names, which are the roughly assigned topics. SOTA methods chosen for feature extraction and classification models are OpenAI Embeddings and XGBoost. Our research shows that this combination of SOTA methods has the potential to improve the performance of current topic classification of publications.","topic classification; openai embeddings; XGBoost; Crossref; Alexandria3k","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:b4fad585-85d7-4bfa-ba37-e93b005e939b","http://resolver.tudelft.nl/uuid:b4fad585-85d7-4bfa-ba37-e93b005e939b","Synthetic data generation for the optimization of strains in metabolic engineering using generative adversarial networks","Jarosz, Marcin (TU Delft Electrical Engineering, Mathematics and Computer Science)","Abeel, T.E.P.M.F. (mentor); van Lent, P.H. (mentor); Hanjalic, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","This research investigates the application of Generative Adversarial Networks (GANs) and probabilistic Principal Component Analysis (PPCA) in generating synthetic data for pathway optimization in metabolic engineering. The study aims to compare the performance of these generative models, addressing key questions regarding their utilization, the quality of generated data compared to experimental data, and overall efficiency. The dataset comprises 5000 parameter configurations of kinetic models that simulate a hypothetical pathway. Constructing kinetic models traditionally involves obtaining complex scientific knowledge, a process that may be alleviated through a data-driven approach. Results indicate that both models, tried with different sizes of latent space, demonstrate good performance in modeling the underlying latent space of the data. However, GANs with the right set of parameters exhibit a better performance, evidenced by lower KL divergence and superior visual structure in the generated data. The findings highlight the potential of GANs to outperform probabilistic PCA, offering valuable insights for more cost-effective and streamlined strain optimization in metabolic engineering. Overall, this research advocates for further investigation of GANs capabilities in metabolic engineering as a potentially powerful tool for synthetic data generation.","","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:f196ff1d-8a37-466f-96a3-e2a6f83d6e5e","http://resolver.tudelft.nl/uuid:f196ff1d-8a37-466f-96a3-e2a6f83d6e5e","Clustering Learning Curves in Machine Learning using K-Means Algorithm: Can patterns be identified amongst learning curves after the application of the K-Means algorithm using point and statistical vectors?","Ramsundersingh, Pravesha (TU Delft Electrical Engineering, Mathematics and Computer Science)","Viering, T.J. (mentor); Turan, O.T. (graduation committee); Delft University of Technology (degree granting institution)","2024","A learning curve can serve as an indicator of the “performance of trained models versus the training set size” [1]. Recent research on learning curve analysis has been carried out within the Learning Curve Database (LCDB) [2] This paper will investigate if there are similarities amongst these curves by clustering those provided by the LCDB. The experiment employs two distinct input parameters: point vectors and statistical vectors. By conducting individual learner analysis, individual dataset analysis, principal component analysis, and other experiments, patterns are isolated for both input sets. Upon further exploration of shapes and distributions, the concluding remark is that the point vector clustering produced one key concrete pattern amongst certain learning techniques. In contrast, the statistical vector findings are more inconclusive and do not exhibit a clear distinction that could be linked to any dominant patterns.","Machine learning; clustering; learning curves","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:f5320370-68dc-4da8-8c96-d08ee54b9446","http://resolver.tudelft.nl/uuid:f5320370-68dc-4da8-8c96-d08ee54b9446","Navigating the Pedagogical Landscape: An Exploration of Machine Learning Teaching Methods","Zlei, Andreea (TU Delft Electrical Engineering, Mathematics and Computer Science)","Migut, M.A. (mentor); Tielman, M.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","This study delves into machine learning (ML) education by conducting a comprehensive literature review, a targeted survey of ML lecturers in Dutch universities, and a comparative experiment. These methods aid in addressing the challenges of aligning teaching methods with the evolving nature of ML and the growing demands of the field, and fill in knowledge gaps on the success of different teaching methods in ML education. The paper investigates whether traditional methods are effective in equipping future engineers with the necessary skills for tomorrow's challenges, amidst the rapid advancement of ML and its applications. The literature review explores the range of teaching methods in ML education and not only, emphasizing a shift towards technology-enhanced and active learning approaches when teaching ML. A survey of ML lecturers explores the landscape of ML education in Dutch universities. The study investigates teaching methodologies, tools, and challenges, providing valuable insights into the evolving practices of ML instruction. Findings indicate a predominant trend towards adopting a blended approach, with lectures, projects, and group work forming core instructional methods. Virtual environments, active learning strategies, and staying informed through community engagement are highlighted. Word frequency and thematic analyses reveal key themes, emphasizing student-centric learning, practical application, and the integration of diverse teaching methods. Additionally, an experimental comparison of two teaching methods, lecture and jigsaw, sheds light on their seemingly similar efficacy when applied to the domain of ML education. The research contributes to the optimization of ML education practices, offering comprehensive insights for educators and policymakers.","Machine Learning; machine learning education; Higher Education; instructional approaches","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:73ab0c4a-a57d-44f6-ab41-264fa0aa1d00","http://resolver.tudelft.nl/uuid:73ab0c4a-a57d-44f6-ab41-264fa0aa1d00","Use Reinforcement Learning to Choose Activities for Preparing to Quit Smoking: How Effective a Reinforcement Learning Model is for Choosing Activities that Optimizes the Likelihood that Users Return to the Next Session and the Effort Users Spend on Their Activities?","Zhang, Meng (TU Delft Electrical Engineering, Mathematics and Computer Science)","Brinkman, W.P. (mentor); Albers, N. (mentor); Wang, H. (graduation committee); Delft University of Technology (degree granting institution)","2024","Unhealthy behaviors such as smoking is the major cause for premature deaths and changing behaviors by oneself can be difficult. That is where eHealth applications come into rescue. One of the recent research explored the possibility of using a Reinforcement Learning model to choose persuasive types for a virtual coach to adopt to persuade people to prepare for smoke-quitting and it has shown advantages. However, there are still more aspects to investigate in this context except the persuasive types of the messages, and this paper intended to further look into using reinforcement learning to choose activities for preparing the users to quit smoking, To be more specific, we implemented and evaluated a reinforcement learning model to choose activities to optimize both the effort spent by the users and also the likelihood of them staying for the next session. The result suggests that reinforcement learning is a promising approach to choose activities for people to prepare for quitting smoking and it can move the users to states that they are more likely to spend a good effort on the activities and are more likely to come back to the next session.","","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:a2c5e474-cd2d-4096-bc2d-5ef2ac76803f","http://resolver.tudelft.nl/uuid:a2c5e474-cd2d-4096-bc2d-5ef2ac76803f","Learning Curve Extrapolation using Machine Learning: Benefits and Limitations of using LCPFN for Learning Curve Extrapolation","Johari, Pratham (TU Delft Electrical Engineering, Mathematics and Computer Science)","Viering, T.J. (mentor); Turan, O.T. (mentor); Hung, H.S. (graduation committee); Delft University of Technology (degree granting institution)","2024","This study explores the extrapolation of learning curves, a crucial aspect in evaluating learner performance with varying dataset sample sizes. We use the Learning Curve Prior Fitted Network (LC-PFN), a transformer pre-trained on synthetic data with proficiency in approximate Bayesian inference, to investigate its predictive accuracy using the Learning Curve Database (LCDB). The assessment involves MSE as an error metric, with 2 baselines from previous studies where we see it outperform the baseline in some cases and keep on par in others. Additionally, we scrutinize instances where the LC-PFN model may exhibit shortcomings to identify trends in curve extrapolation failures, offering insights for potential modifications to the training dataset. We see a pattern in learners where LC-PFN performs consistently poorly on, whereas no significant pattern can be seen for datasets.","Learning curve; Extrapolation; LCDB; LCPFN; Machine learning","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:e8ea1f64-6640-464f-98c7-942c13333d90","http://resolver.tudelft.nl/uuid:e8ea1f64-6640-464f-98c7-942c13333d90","Landmarks in Planning: Using landmarks as Intermediary Golas or as a Pseudo-Heuristic","van Maris, Bart (TU Delft Electrical Engineering, Mathematics and Computer Science)","Hanou, I.K. (mentor); Dumančić, S. (mentor); Cruz, Luis (graduation committee); Delft University of Technology (degree granting institution)","2024","Algorithmic planners occasionally waste effort and thus computing time trying to solve certain tasks, as they often lack the human ability to recognize essential paths. These essential paths, termed landmarks, are vital for optimizing planning processes. This study revisits landmark-based planning methods introduced by Richter, Helmert, and Westphal in their 2008 paper, adapting and implementing them within a different framework, SymbolicPlanners, using the Julia programming language. The primary research question explores the performance of using landmarks as intermediary goals and pseudo-heuristics in the SymbolicPlanner framework. Sub-questions delve into the effectiveness of specific planning strategies, such as A∗ Planner with GoalCount and HAdd heuristics, as well as planners utilizing landmarks. Evaluation over diverse domains reveals that LMLocal and LMLocalSmart outperform the basic GoalCount
heuristic and are on par with the HAdd heuristic. LMCount, despite solving fewer instances, exhibits speed improvements over GoalCount in the instances that they both solve. Discussion highlights limitations, such as the non-exhaustive interference check in LMLocalSmart and limiting factors in the SymbolicPlanner framework.","Algorithmics; Planners; Landmarks; Heuristics","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:09603d28-aa2b-48a5-9f61-095fa1084e57","http://resolver.tudelft.nl/uuid:09603d28-aa2b-48a5-9f61-095fa1084e57","Learning Curves: How do Data Imbalances affect the Learning Curves using Nearest Mean Model?","Feng, Kevin (TU Delft Electrical Engineering, Mathematics and Computer Science)","Viering, T.J. (mentor); Turan, O.T. (mentor); Delft University of Technology (degree granting institution)","2024","This research investigates the impact of data imbalances on the learning curve using the nearest mean model. Learning curves are useful to represent the performance of the model as the training size increases. Imbalanced datasets are often encountered in real-life scenarios and pose challenges to standard classifier models impacting their performance. Thus, the research question is ”How do data imbalances affect the learning curves using the nearest mean model?”. To answer the question, an experiment is conducted using data from a multivariate Gaussian distribution to sample varying levels of imbalances. The imbalance ratio explored is [0.1, 0.2, 0.3, 0.4, 0.5], representing the percentage of the dataset that consists of the minority class. The findings indicated that as the data becomes more imbalanced, the learning curves reach the accuracy plateau at a later rate. The analysis of the curve parameter which follows the logistic function suggests that imbalances have an impact on the maximum achievable accuracy and rightward shift of the curves. However, the maximum achievable accuracy is non-significant and the shape of the curves remains similar. Additionally, false negatives have a significant impact on the learning curves.","Learning Curve; Imbalance Data sets; Machine Learning","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:eae44363-4d18-4612-8382-ad08941fff66","http://resolver.tudelft.nl/uuid:eae44363-4d18-4612-8382-ad08941fff66","The impact of Goal-Oriented Visualization on Academic Performance: A Case study in Machine Learning","Tesink, Kriss (TU Delft Electrical Engineering, Mathematics and Computer Science)","Migut, M.A. (mentor); Tielman, M.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","This research investigates the impact of goal-oriented visualization on machine learning knowl-edge acquisition, particularly exploring its poten-tial to address procrastination in academic settings. By examining participants with no prior machine learning experience, the study employs compara-tive and correlational measures to analyze quiz per-
formance, study times, and visualization practices. While encouraging trends are observed, the small sample size emphasizes the need for further re-search to definitively establish the impact of visu-alization on academic performance. The study ad-heres to ethical guidelines, ensuring participant pri-vacy and obtaining informed consent, contributing to responsible research practices.","visualization; academic performance; positive thinking","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:23643d2e-c4dc-49d5-a497-0583e9d8b093","http://resolver.tudelft.nl/uuid:23643d2e-c4dc-49d5-a497-0583e9d8b093","Discovering Digital Siblings: Quantifying Inter-Repository Similarity Through GitHub Dependency Structures","Rębacz, Mateusz (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Software Engineering)","Proksch, S. (mentor); Huang, S. (mentor); Olkhovskaya, Julia (graduation committee); Delft University of Technology (degree granting institution)","2024","Open Source developers typically use Git repositories to transparently store the source code of projects and contribute to the code of others. There are millions of repositories actively hosted on platforms such as GitHub. This presents an opportunity for sharing knowledge between related projects – the so-called digital siblings. Finding repositories similar to one's own can allow for better developer collaboration and knowledge transfer. However, due to the large volume of projects, manually locating digital siblings of a project can be difficult. Hence, this paper proposes a novel approach, based on the dependency structures of GitHub repositories, that allows for calculating inter-repository similarity and subsequently querying for similar projects. We aim to answer the research question: How can the dependency structures of GitHub repositories be leveraged to find their digital siblings? This research includes an empirical evaluation of various similarity metrics and clustering techniques for GitHub repositories. Our results show that dependency structures are a reliable characteristic for measuring similarity between projects. We also identify the specific metrics and clustering techniques as particularly efficient. Lastly, we propose and evaluate a composable similarity metric to allow our findings to be combined with the research of the other Research Project group members.","GitHub; Repository; Similarity Metrics; Dependency Analysis; Dependencies; git","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:4b1ba358-509f-44e4-96cb-f768c82e21fe","http://resolver.tudelft.nl/uuid:4b1ba358-509f-44e4-96cb-f768c82e21fe","Long-Term Memory Retention of Educational Content: How Machine Learning concepts can be remembered for the rest of our careers with the right practice questions","Mušić, Ismail (TU Delft Electrical Engineering, Mathematics and Computer Science)","Migut, M.A. (mentor); Tielman, M.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","To aid the teachings of machine learning (ML), the usage of elaborative interrogative practice questions (EIPQ) is proposed to increase the long-term memory retention of said teaching. Firstly, the existing expectations of students in the current educational landscape are analyzed by taking a look at the undergraduate course present in Delft University of Technology's own Computer Science and Engineering program (CSE2510). Then, relevant theories and techniques for long-term memory retention through practice questions are introduced and applied to CSE2510 content. Finally, an experiment was carried out where roughly half of the participants made use of these newly created EIPQ, while the other half mostly used existing questions, serving as a control group (CQ). The results showed that, compared to the existing practice questions, the use of the newly created EIPQ had a profound impact on the long-term knowledge retention of the learning content. The participants who made use of EIPQ had an average retention ratio of 0.82, compared to the participants who made use of CQ, who had an average retention ratio of 0.57. Therefore, it is suggested that including EIPQ in our current educational model has favorable benefits to the students' knowledge retention of the learned content. A recommendation is made on how to carry out these methods in practice, keeping compatibility with existing learning objectives in mind.","Elaborative Interrogation; Machine Learning (ML); knowledge retention; teaching method; Practice Question; Real-world problems; Long-term memory","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project","51.999069,4.378320"
"uuid:a2bd53cf-1023-47f3-8212-371d50aaeca9","http://resolver.tudelft.nl/uuid:a2bd53cf-1023-47f3-8212-371d50aaeca9","A comparative analysis of coding approaches in machine learning among computer science students and non-computer science students","Dujmović, Grga (TU Delft Electrical Engineering, Mathematics and Computer Science)","Migut, M.A. (mentor); Tielman, M.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","The increasing presence of Machine Learning in all fields of study requires an improvement in how it is taught. Previous research on this topic examined how to teach ML concepts and highlighted the importance of using technology and leveraging relevant pedagogical content knowledge. It did not compare the impact of previous programming knowledge on the students' approach to solving ML problems. This paper explores the differences in implementation of 60 Machine Learning coding assignments using metrics that were determined by previous research to be a good indicator of code quality and computational thinking. By analysing the code submissions with these metrics, the results show several interesting insights about the students' use of functions, variables and the explanations of their thought process. However, results of the metrics are mostly inconclusive. The results from this study highlight the need for additional research on this topic to ensure that people with limited Computer Science knowledge are able to learn about it and implement it in their disciplines.","Machine Learning; Comparative analysis; Coding; Student","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:f39cf770-4bb9-4b2e-a3a4-88ad7f07a66a","http://resolver.tudelft.nl/uuid:f39cf770-4bb9-4b2e-a3a4-88ad7f07a66a","Isolating a Tree’s Skeleton using a 3-Dimensional Reconstruction","Sahay, Shashwat (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Computer Graphics and Visualisation)","Eisemann, E. (mentor); Kellnhofer, P. (mentor); Uzolas, L. (mentor); Reinders, M.J.T. (graduation committee); Delft University of Technology (degree granting institution)","2024","L-Systems allow for the efficient procedeural generation of trees to be used for rendering in video games and simulations. Currently, however, it is difficult to engineer grammars that mimic the behaviours of real life trees in 3 dimensions. To be able to deduce them, the skeleton of a tree can be used to train a model and generate an L-system for a given tree in particular. The aim of this paper is to provide a pipeline to isolate these skeletons from images of a tree, using Neural Radiance Fields (NeRFs) to reconstruct the tree, and using Laplacian Based Contraction to retrieve the underlying skeleton. We find that this approach leads to 3-dimensional topologies that very closely resemble the given tree.","NERF; L-system; Skeletonization; Laplacian-Based Contraction","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:28d13e2d-c7ee-4fdf-a50b-3dfa842b79b6","http://resolver.tudelft.nl/uuid:28d13e2d-c7ee-4fdf-a50b-3dfa842b79b6","Re-evaluating the Full Landmark Extraction Algorithm: A Performance Analysis of FULL","Tjoen, Noah (TU Delft Electrical Engineering, Mathematics and Computer Science)","Dumančić, S. (mentor); Hanou, I.K. (mentor); Cruz, Luis (graduation committee); Delft University of Technology (degree granting institution)","2024","Landmarks are propositions or actions that must be true at some point in every valid solution plan [16]. Using landmarks, planners can develop solutions more efficiently. Different algorithms exist to extract landmarks from a planning problem. The one used in this study is FULL [13], a landmark extraction algorithm by Marzal et al. from 2011.
In this research, the performance of the FULL algorithm is analysed by comparing the total number of landmarks found to two other landmark extraction algorithms, namely forward propagation by Zhu and Givan [22] and backward propagation by Porteous et al. [16].
The original FULL algorithm is slightly modified, by removing orderings and disjunctive landmark extraction. FULL is implemented using Julia and was run on five different domains from the International Planning Competitions.
All of these domains are logical and 15 problems were randomly selected from them.
FULL managed to extract more landmarks in two out of the five domains, Grid and Logistics, compared to the two aforementioned algorithms.
In the three other domains, FULL matched the number of landmarks found by the best out of the two. The two domains where FULL performed well, were both transportation domains and this is where FULL's performance excels.
Runtime was not an issue when extracting landmarks in four of the five domains. Freecell consistently exceeded the timeout put in place, likely due to a bug.
Furthermore, a higher number of landmarks is also a desired outcome due to its use in planners, either as heuristics or intermediary goals.","Landmarks; Planning","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:ea22d58f-c5e5-402c-a609-f85eb41ea751","http://resolver.tudelft.nl/uuid:ea22d58f-c5e5-402c-a609-f85eb41ea751","Reproducing the concept of ordered landmarks in planning: The effect of ordered landmarks on plan length in forward search","Tervoort, Paul (TU Delft Electrical Engineering, Mathematics and Computer Science)","Hanou, I.K. (mentor); Dumančić, S. (mentor); Cruz, Luis (graduation committee); Delft University of Technology (degree granting institution)","2024","A lot of research has been conducted to make the task of plan generation more efficient. One idea to do so is the use of landmarks, which are sub-goals that must be true in every solution to the problem. The approximation of landmarks has a lower complexity than solving the task itself, and they can be used to guide the planner in the right direction.
In previous work, ideas to order landmarks are proposed and compared to algorithms that do not use them. We verify if this comparison is fair by testing both algorithms implemented in the same language and framework. In our experiment not many problem instances finish in time, but those that do are in line with previous experiments in that on average planners using landmarks produce longer solutions than planners that do not use them.","Planning; Landmarks; Reasonable ordering","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:8d0cdd3e-e68a-4202-a4b1-9b139d49e555","http://resolver.tudelft.nl/uuid:8d0cdd3e-e68a-4202-a4b1-9b139d49e555","Extending SymbolicPlanners with forward propagation landmark extraction","Yang, Ka Fui (TU Delft Electrical Engineering, Mathematics and Computer Science)","Hanou, I.K. (mentor); Dumančić, S. (mentor); Cruz, Luis (graduation committee); Delft University of Technology (degree granting institution)","2024","The Fast Downward planning system is currently mainly used for solving classical problems. Another alternative to Fast Downward is SymbolicPlanners, which sacrifices speed for generality and extensibility. SymbolicPlanners is missing landmark based planners and landmark extraction algorithms. The research question we are trying to answer in this research paper is: What design choices can be made to adapt the forward propagation extraction algorithm into SymbolicPlanners?
The forward propagation landmark generation design choices are discussed and implemented in SymbolicPlanners. The runtime performance of the implementation is only about two times slower than the Fast Downward implementation. Another aspect of the implementation is the incorrect amount of landmarks generated in complex problems caused by limitation in the relaxed planning graph from SymbolicPlanners.","Classical Planning; Propagation; Landmark","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:90f0c7fe-34db-45f3-bd2b-7fec91075d20","http://resolver.tudelft.nl/uuid:90f0c7fe-34db-45f3-bd2b-7fec91075d20","Learning Human Preferences for Physical Human-Robot Cooperation","van der Spaa, L.F. (TU Delft Learning & Autonomous Control)","Kober, J. (promotor); Babuska, R. (promotor); Delft University of Technology (degree granting institution)","2024","Physical human-robot cooperation (pHRC) has the potential to combine human and robot strengths in a team that can achieve more than a human and a robot working on the task separately. However, how much of the potential can be realized depends on the quality of cooperation, in which awarenes of the partner’s intention and preferences plays an important role. Preferences tend to be highly personal, and additionally depend on the cooperation partner and the cooperation itself. They can be hard to define in terms a robot would understand, and may change over time. This thesis focuses on learning ‘useful models’ from observed behavior, to let our robot adapt its behavior to better match its human partner’s preferences, and thus improve the cooperation.
The aim is to capture personalized approximate models of human preferences –how a person likes to do something– from very few interactive observations, providing only small amounts of imprecise data, such that the robot can use the model to improve each user’s comfort. First, we learn a model to predict and optimize the human ergonomics in a pHRC task, such that our robot can ropose a plan, for both the human and itself, to solve the task in a way that is more ergonomic for its human partner. However, people do not necessarily prefer to act ergonomically, nor do we want to impose on them what a robot thinks best. Therefore, next, we apply inverse reinforcement learning (IRL), to capture less restrictive preference models: 1) path and velocity preferences for motion planning, and 2) on a higher level of abstraction, which (grasp or motion) action to initiate for proactive physical support. For learning to take the correct action in cooperation, we developed the disagreement-aware variable impedance (DAVI) controller to smoothly transition between providing active guidance and allowing the human to demonstrate alternative behavior.....","Physical Human-Robot Interaction; Human-Robot Collaboration; human preferences; human-centered planning; Inverse Reinforcement Learning","en","doctoral thesis","","978-94-6483-764-3","","","","Dr. M. Gienger contributed significantly to the realization of the dissertation.","","","","","Learning & Autonomous Control","","",""
"uuid:34b2de43-c1c3-40d9-869b-9ce7ce572e3e","http://resolver.tudelft.nl/uuid:34b2de43-c1c3-40d9-869b-9ce7ce572e3e","Logarithmic law of large random correlation matrices","Parolya, N. (TU Delft Statistics); Heiny, Johannes (Ruhr-Universität Bochum); Kurowicka, D. (TU Delft Applied Probability)","","2024","Consider a random vector y = Σ 1/2 x, where the p elements of the vector x are i.i.d. real-valued random variables with zero mean and finite fourth moment, and Σ 1/2 is a deterministic p × p matrix such that the eigenvalues of the population correlation matrix R of y are uniformly bounded away from zero and infinity. In this paper, we find that the log determinant of the sample correlation matrix R based on a sample of size n from the distribution of y satisfies a CLT (central limit theorem) for p/n → γ ∈ (0, 1] and p ≤ n. Explicit formulas for the asymptotic mean and variance are provided. In case the mean of y is unknown, we show that after re-centering by the empirical mean the obtained CLT holds with a shift in the asymptotic mean. This result is of independent interest in both large dimensional random matrix theory and high-dimensional statistical literature of large sample correlation matrices for non-normal data. Finally, the obtained findings are applied for testing of uncorrelatedness of p random variables. Surprisingly, in the null case R = I, the test statistic becomes distribution-free and the extensive simulations show that the obtained CLT also holds if the moments of order four do not exist at all, which conjectures a promising and robust test statistic for heavy-tailed high-dimensional data.","CLT; dependent data; large-dimensional asymptotic; log determinant; random matrix theory; sample correlation matrix","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Statistics","","",""
"uuid:7dae1d8e-d03e-498a-8295-3e01ac9e9050","http://resolver.tudelft.nl/uuid:7dae1d8e-d03e-498a-8295-3e01ac9e9050","Electrochemical Ammonia Synthesis: Development of a Cell With a Hydrogen Permeable Electrode","Ruis, Sidi (TU Delft Applied Sciences)","Mulder, F.M. (mentor); van Noordenne, D.D. (graduation committee); Kortlever, R. (graduation committee); Urakawa, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Ammonia is essential for global food production as a component of fertiliser, and a potential energy carrier in the energy transition. Electrochemical ammonia synthesis faces numerous challenges as an alternative to the carbon intensive Haber-Bosch process, including competition from hydrogen evolution, and mass transport limitations. An unconventional cell design with a hydrogen permeable electrode could help to address these problems. The reaction mechanism and performance of ammonia synthesis using hydrogen permeable electrodes was investigated at elevated temperatures and pressures of up to 120 °C and 8 bar. Furthermore, a facile method for enhancing the electrochemical surface area of the electrode was developed and tested. Operation at elevated pressure resulted in a moderate increase in cell performance. However, replenishment of the nitrogen vacancies in the nickel nitride catalyst through dinitrogen adsorption is identified as the elementary step that limits activity and stability. The amount of pre-deposited N is found to significantly influence the ammonia production rate and its stability. Dynamics of ammonia desorption could also play a role in nitride regeneration. In future studies, the presence of a decomposition reaction of the nitride should be investigated. Usage of more stable nitride species or a combination of host nitride and dopants is recommended to improve stability and simultaneously promote dinitrogen activation and hydrogenation to ammonia. These findings expand the understanding of the mechanisms underlying the nitrogen reduction reaction, paving the way for the development of a more efficient green ammonia synthesis process.","Ammonia; Catalysis; Electrochemistry; Energy Storage; Synthesis; hydrogen; Ammonia synthesis","en","master thesis","","","","","","","","","","","","Applied Physics | Physics for Energy","",""
"uuid:c6d4a434-d061-4b3e-a9e2-0f86d17fe9f6","http://resolver.tudelft.nl/uuid:c6d4a434-d061-4b3e-a9e2-0f86d17fe9f6","Eulerian Stochastic Field method with FGM tabulation: for Partially Premixed Hydrogen Flames","Vloeberghs, Victor (TU Delft Aerospace Engineering)","Langella, I. (mentor); Roekaerts, D.J.E.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis introduces a newly-developed turbulent combustion model, as a next step towards modelling hydrogen combustion in aircraft engines. The proposed model (FGM-ESF) merges the Flamelet Generated Manifold approach's tabulated chemistry with the Eulerian Stochastic Field method's statistical treatment of flame-turbulence interactions at the subgrid scales, which are not resolved in LES. This hybrid model excels in managing complex combustor dynamics, high turbulence, and both premixed and non-premixed combustion modes, all while maintaining computational efficiency. Validated with a lifted turbulent H2/N2 jet flame in vitiated coflow, reflecting typical combustor conditions, the FGM-ESF model produces accurate predictions of mean velocity, temperature, and mixture in close agreement with the experiments. Comparatively, its performance matches the more costly, fully transported chemistry ESF model, showing limited sensitivity to the number of stochastic fields. The balance between computational efficiency and precision in the FGM-ESF model highlights its importance in the advancement of hydrogen-powered aircraft engines.","Eulerian Stochastic Field, Partially Premixed Hydrogen Flame, Large Eddy Simulation, Flamelet Generated Manifold","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:3c1bfcdc-7aff-4ed6-a2db-6f768863dea6","http://resolver.tudelft.nl/uuid:3c1bfcdc-7aff-4ed6-a2db-6f768863dea6","Bench marking AmpliDiff for Human Monkeypox, Hiv-1 and Influenza-A","den Boon, Kevin (TU Delft Electrical Engineering, Mathematics and Computer Science)","Baaijens, J.A. (mentor); van Bemmelen, J. (mentor); Raman, C.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","AmpliDiff provides a method which takes a list of genomes and their lineages, and finds a set of amplicons and their primers in such a way that these amplicons can be used to differentiate between the lineages of a specific virus. While it has been shown that AmpliDiff find results comparable to whole genome sequencing for SARS-CoV-2 when looking at abundance estimations, it is not know how well it performs for other viruses, or what factors of a virus impacts the performance of the amplicons found by AmpliDiff.\\
In this paper we will be showing the effectiveness of AmpliDiff on Human monkeypox, HIV-1 and Influenza-A.
By running AmpliDiff for the three viruses mentioned above, we obtain sets of amplicons, which are used to do a lineage abundance estimation. By then comparing the estimation to the know abundance we calculate the Mean Average Error (MAE). This MAE will then be used to compare against the MAE obtained from doing a abundance estimation based on whole genome sequencing.
By comparing the amplicons against whole genome sequencing (wgs), we show that using viruses with longer genomes positively impacts the performance of the amplicons. We also show that the amount of misalignment characters added by the Multiple Sequence Alignemnt (MSA), impacts the required settings for AmpliDiff to find amplicons, and can negatively impact the MAE.
Finally, we show that AmpliDiff can be run, with some minor changes to the code base, on segmented genomes, with performance similar to that of single segment genomes.","AmpliDiff; Amplicon; Sequence","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:0ec80b08-2aa3-47d2-a86a-62c8cf791051","http://resolver.tudelft.nl/uuid:0ec80b08-2aa3-47d2-a86a-62c8cf791051","Robust Autopilot Design by Structured H∞ Loop Shaping: An Agile Aerospace Vehicle Application","Loukisas, Chari (TU Delft Aerospace Engineering)","Theodoulis, S.T. (mentor); Mulder, Max (graduation committee); Mooij, E. (graduation committee); Delft University of Technology (degree granting institution)","2024","This study demonstrates an effective systematic control design procedure by applying H∞ Loop-Shaping with a structured controller on an agile aerospace vehicle with a focus on automation. The gain-scheduled implementation is additionally described and tested with non-linear simulations, including a realistic moving point-hit scenario with guidance. The imposed robustness and performance requirements are met for most linear design points and for the non-linear simulations. The resulting autopilot design procedure is deemed effective in both the design procedure and implementation. It is subject to certain recommendations for improvement and extension.","Controller Robustness; Agile; Robust Control; loop shaping; h infinity","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:8510487e-d59f-4a89-93dd-dc685cd06bb6","http://resolver.tudelft.nl/uuid:8510487e-d59f-4a89-93dd-dc685cd06bb6","A Bayesian Approach to Yield Curve Modelling and Forecasting with Stochastic Volatility for Interest Rate Risk Management","Sarkisian, David (TU Delft Electrical Engineering, Mathematics and Computer Science)","Bierkens, G.N.J.C. (mentor); Meester, L.E. (graduation committee); Specker, Ivo (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis explores how forecasts of Dutch government bond yields can be improved by extending the current Dynamic Nelson-Siegel (DNS) model, used by the Dutch State Treasury Agency (DSTA), with stochastic volatility modeling and a Bayesian approach to parameter estimation and forecasting. The primary goal was to determine if the model extensions together with the Bayesian approach could improve the accuracy of yield forecasts given the highly volatile interest rate environment. In particular, we aimed to improve the ""worst-case"" forecasts, which we have defined as the upper bound of the 95% credible region with respect to the observed bond yields. To this end, we began with a baseline state-space model, resembling the current model in a state-space framework. Subsequently, we applied the findings from both in-sample and forecasting results as well as the findings from a literature review on volatility modeling to develop different models including two volatility models.
The volatility of the DNS model extensions is modeled as a GARCH process through the observation noise based on findings in the literature. This allowed for computationally efficient state estimation using a modified Kalman filter. Then, employing the Random Walk Metropolis algorithm for parameter estimation allowed us to use Bayesian multiple-step ahead forecasting. In particular, a comparative analysis of various models showed that while the current model performed better than expected, it was significantly outperformed in-sample by the DNS model with AR(1) observation noise (DNS-ARRW) and the DNS model with GARCH(1,1) observation noise volatility (DNS-OV). The Bayesian forecasting method particularly improved capturing the uncertainty of increasing yields in twelve-months ahead forecasts. Moreover, the two volatility models showed promising in-sample performance, but only one (DNS-OV) showed relatively good forecasting performance as well. Furthermore, the DNS-ARRW model consistently showed the best performance both in-sample and in forecasting.
In conclusion, the Bayesian approach to parameter estimation and forecasting proved effective in accounting for more variability in increasing forecast yields and simulating the direction of forecasts slightly better than the current MLE-based method. Moreover, the DNS-ARRW model showed significantly better worst-case forecasting performance, whereas the volatility models had a mixed performance.","Yield curve modeling; Bayesian forecasting; Stochastic volatility; Dynamic Nelson-Siegel; Markov Chain Monte Carlo","en","master thesis","","","","","","","","","","","","Applied Mathematics","",""
"uuid:caaad9ee-d880-4622-acef-527e670ddcf1","http://resolver.tudelft.nl/uuid:caaad9ee-d880-4622-acef-527e670ddcf1","Magnetorheological fluid damper for tunable damping in active mechanical metamaterials","Habbal, Samer (TU Delft Mechanical, Maritime and Materials Engineering)","Hunt, A. (mentor); Delft University of Technology (degree granting institution)","2024","In the era of advancing technology, the demand for specialized engineering materials has risen significantly. Active Mechanical Metamaterials (AMMs) offer a novel approach to engineering materials with tunable mechanical properties. This research focuses on developing tunable damping active mechanical metamaterials (AMMs) by incorporating magnetorheological fluid (MRF) damper into a compliant mechanism unit cell. This unit cell transforms linear displacement into rotation at the centre, precisely where the damper is located. First, The AMM unit cell has been designed with a compliant structure that converts the unit input into an embedded MRF damper. After that, the dynamic behaviour of the unit cell was studied by combining analytical and FEM modelling to characterize the stiffness and damping of the unit cell. A prototype has been built, and the damping and stiffness have also been experimentally characterized.
The results highlight key findings, including numerical data, offering insights into the efficiency of the unit cell's compliant transformation mechanism and the tunable damping achieved through MRF dampers, where the damping ratio can be adjusted from 0.02 to approximately 0.03 when 1.4 A of current is applied. This study represents a significant advancement in active mechanical metamaterials, showcasing a novel unit cell design where the magnetorheological fluid has been used for the first time to achieve tunable damping in active mechanical metamaterials.
The success of this study is evident in the convergence of theoretical predictions with experimental outcomes, emphasizing the robustness of the proposed design and modelling methodologies. The implications of this research extend to diverse applications in structural engineering and vibration control, with a particular focus on high-tech systems. These findings provide valuable guidance for researchers and engineers working in high-tech industries, offering practical insights that can significantly impact the development and implementation of innovative solutions in these fields.","smart materials; magnetorheological fluid; Damping; Active Mechanical Metamaterial; Vibration Testing","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Mechatronic System Design (MSD)","",""
"uuid:deecc335-3d71-4bcd-970c-d4bb6aa04c35","http://resolver.tudelft.nl/uuid:deecc335-3d71-4bcd-970c-d4bb6aa04c35","Arc selection strategies for application-aligned monitoring using InSAR","CHITTARANJANA, RAM (TU Delft Civil Engineering & Geosciences)","Hanssen, R.F. (mentor); Wang, Y. (mentor); de Roode, S.R. (graduation committee); Delft University of Technology (degree granting institution)","2024","Interferometric Synthetic Aperture Radar (InSAR) is a geodetic technique that is capable of monitoring surface displacements up to millimeter-level of precision. The end products from conventional InSAR processing are application-agnostic, which means that they are not optimized for any particular application. InSAR products could be more beneficial if tailored for a relevant application, particularly if expert users can tune the products according to their monitoring requirement. Here, we develop tools for application-aligned monitoring by means of the selection of application-relevant arcs between scatterers in InSAR. We are interested in the use of local (short) arcs between point scatterers, as these arcs are more likely to be better suited for monitoring localized differential deformation, and may provide observations of better quality due to the fact that they are less prone to atmospheric noise.
We first compare the time series of local arcs and conventional time series w.r.t.\ a common reference point based on their deformation behavior. The comparison reveals that the time series of local arcs are capable of providing additional information on deformation behavior over the conventional method. However, the quality of observations in local arcs in general is found to be more variable, and often even worse than those from the conventional method. Most likely, the reason for this is the absence of noise reduction in local arcs in comparison to the time series from the conventional method which optimizes the selection of the common reference point to reduce noise in the time series.
In addition, to optimize the arc selection for a given application, we propose an arc tuning strategy, where criteria can be set based on arc parameters, i.e., the length, the elevation difference (between point scatterers) and the azimuth of the arc. We also introduce the arc clustering method as an exploratory data analysis algorithm for general-purpose monitoring using local arcs. Both of these methods are demonstrated on test scenarios over the quay walls along the canal network of Amsterdam. The demonstration on arc tuning shows that arc setting criteria on arc geometry parameters are adequate to select arcs with certain orientations, and the selection can be further aided by estimating displacement parameters with multiple hypothesis testing. The results from the arc clustering show the potential of detect instability over a certain area using arcs without knowing the motion of the specific object.
This study contributes to monitoring deformation where the InSAR data can be optimally attuned based on a particular application. In order to convey information on selected arcs effectively, a visualization tool based on an interactive map is created in a jupyter notebook environment.
This design differs from cast-in-situ traditional composite floor systems by having a concrete deck divided into three separate parts that are connected by bolted shear connectors. The composite floor consists of composite girders and concrete decks. A key advantage of this system is the ability to extract the concrete deck from existing floor systems, offering economic benefits and reducing carbon emissions over its life cycle. The mechanical performance of the newly designed connection between two concrete segments (a composite beam and a concrete deck) is examined through a shear and bending model using Abaqus Software.
The shear model does not represent a real case loading, and it is introduced to gain confidence in the numerical analysis due to the absence of experimental data in this research. The specimen consists of two concrete blocks being pulled apart. These blocks are connected by a demountable shear connector (bolt) in the middle.
A three-point bending model presents the mechanical behaviour and realistic potential failure modes of the innovative demountable ""concrete to concrete"" connection. It consists of three connected concrete segments. This model reveals failure modes, including cracking at the “re-entrant corners” of the connection points, crushing of concrete at the mid-plane of the connection and under the bolt nut, and transverse concrete cracking originating from the bolt hole, refer to Figure 6.26.
To enhance the structural behavior of this modularised floor system, several methods are investigated. First, adding steel plates at the connections effectively mitigates concrete crushing at the mid-plane and prevents cracking at the re entrant corners. Second, relocating the connection to zero-bending moment positions results in a notable reduction in the three failure modes, improving loading capacity by about 10%. Furthermore, the environmental impact of this novel design is noteworthy. With the assumption given in this thesis, for an area of 5.67m*8m concrete deck, reusing the newly designed concrete deck can result in a savings of approximately 4.2 tonnes of CO2 emissions per subsequent life cycle. Similarly, reusing concrete decks from existing buildings can lead to a reduction of around 2.33 tonnes of CO2 emissions per life cycle with this size of the floor. Based on the assumptions made in this research, the results suggest that the newly designed concrete deck may have a lower loading capacity than traditional concrete slabs. However, its potential economic and environmental advantages make it a promising topic for future investigations.","Demountable; ""concrete to concrete"" connection; Modularised floor system; Concrete Deck; Bolted shear connectors; Second cycle of life; Life cycle Assessment","en","master thesis","","","","","","","","","","","","Civil Engineering | Structural Engineering | Steel and Timber Construction","",""
"uuid:6cfb2ccc-f565-4fe5-8b52-61e7092bdfa2","http://resolver.tudelft.nl/uuid:6cfb2ccc-f565-4fe5-8b52-61e7092bdfa2","Contribution of source code identifiers to GitHub project similarity: Which other GitHub projects are similar to yours?","Crienen, Juul (TU Delft Electrical Engineering, Mathematics and Computer Science)","Proksch, S. (mentor); Huang, S. (mentor); Olkhovskaya, Julia (graduation committee); Delft University of Technology (degree granting institution)","2024","GitHub is an online platform that hosts millions of projects. Many of these projects have the same topic or share the same goal. Finding similar projects which can be used as role models, inspiration or examples can help developers meet their requirements faster and more efficiently. Previous studies have been successful in finding similar GitHub projects, but they do not share how well their proposed metrics indicate similarity.
Our research and analysis seek to find the contribution of source code identifiers to overall project similarity. We define project similarity and define each type of identifier we evaluate. After these steps, we extract the defined types of identifiers from a list of projects. From this list of projects, we use twenty projects as queries for our analysis. We then analyze all identifiers using techniques such as TF-IDF and LSA. Our findings are that combining all types of identifiers results in the highest chance of having the same topic when looking at the most similar project. We also find that splitting each identifier on its casing and combining all split identifiers results in the highest chance that the most similar project found is similar. We therefore see that source code identifiers are reasonably contributing to overall project similarities.","GitHub; similar projects; source code identifiers; language processing; text analysis","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:7bdf4ec5-5637-4339-8953-06b43faaa052","http://resolver.tudelft.nl/uuid:7bdf4ec5-5637-4339-8953-06b43faaa052","Plug & Live: Modular Adaptation of Polish Large Panel Concrete Housing: Based on an example of the W-70 system","Zapaśnik, Marta (TU Delft Architecture and the Built Environment)","Snijders, A. (mentor); Quist, W.J. (graduation committee); Tomesen, P.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","How to adapt the Polish Large Panel concrete system housing to increase the living diversity with modular architecture? This graduation topic aligns with the Architectural Engineering studio approach and the master track's emphasis on integrating technology and exploring circular adaptation strategies. The design of Plug & Live: Modular Adaptation of Polish Large Panel Concrete Housing is linked to the foundational concept of adaptable and flexible architecture, incorporating a user-based selection principle and activating roofscapes by greenery enhancement, energy production and water harvesting. Given the multi-layered nature of this approach, the primary challenge in the design study was distilling the minimum viable approach while still showcasing the potential for diverse architectural outcomes and evolution over time. This design philosophy represents a notable departure from conventional building practices, emphasizing a shift away from static structures towards designs capable of evolution led by dynamic change of the residents’ living needs.
Academically, this research adds the Polish perspective to the adaptive reuse discourse by exploring how architectural interventions can preserve the heritage from the 60s and 70s cultural, social and spatial significance while meeting future needs and improving the spatial, energetical and aesthetical values. By examining the exemplary W-70 system from Poland, which shares historical and architectural similarities to the prefab systems from other countries, this research provides valuable insights and recommendations that can inform the debate on future-proof adaptation strategies addressing the pressing need for affordable social housing in these regions. As a result, the neglected yet ubiquitous post-Soviet housing stock can become architecture beyond political ideologies, trends or profit-driven market.
The design proposal incorporates research findings while delineating between individual and community-based choices across various architectural tiers. Commencing at the smallest scale, XS (façade), where each panel offers customization options, it progresses to the S scale (apartment), enabling residents to expand their living spaces with winter gardens and green terraces. Transitioning to the M scale (cluster), new rooftop additions are introduced, followed by the L scale (block), where buildings are distinguished by unique color and material identities. This progression culminates at the XL scale (neighborhood), where each subsequent estate obtains its distinct identity through diverse façade compositions and elements, while adhering to the overarching design strategy.Ultimately, the establishment of the design minimum provides a starting point for subsequent extensions that contribute additional values across social, economic, and environmental dimensions, all while preserving the unique identity and individuality of buildings at various scales. ","Adaptive Reuse; Modern Movement; Modular Architecture; Participatory Design; Architectural Identity; Large Panel Concrete System Housing","en","master thesis","","","","","","https://tud365-my.sharepoint.com/:p:/g/personal/mzapasnik_tudelft_nl1/EcT7pECLqilInvVIIdC3iD0BDR-FEB8DHbYmgtqoowBjPA?e=BoTsKw MartaZapasnik_Presentation","","","","","","Architecture, Urbanism and Building Sciences | Architectural Engineering","",""
"uuid:5f831793-2dbc-4b24-9d92-1441f2d8ba16","http://resolver.tudelft.nl/uuid:5f831793-2dbc-4b24-9d92-1441f2d8ba16","Optimizing Routing and Fleet Sizing for Flash Delivery Operations","Kronmüller, M. (TU Delft Learning & Autonomous Control)","Alonso Mora, J. (promotor); Babuska, R. (promotor); Delft University of Technology (degree granting institution)","2024","In recent years, Flash Delivery services have gained great popularity. Flash Delivery is a service where goods of daily need can be ordered on-demand and subsequently are delivered to the customer within a short time window, for example, in the next ten minutes. Operational efficiency and cost management are vital for sustainability in this competitive landscape, especially in the long term. To this end, this thesis aims to improve operational planning for Flash Delivery Operations. It focuses on two fundamental questions critical for the success of Flash Deliveries: the associated Vehicle Routing Problem and the associated Fleet Sizing Problem. The Vehicle Routing Problem aims to determine how to best utilize a given fleet of vehicles to deliver the requested orders efficiently, while the Fleet Sizing Problem involves finding the optimal number of vehicles required to serve the given demand. The primary objective of this dissertation is to provide algorithmic contributions, specifically focusing on optimizing vehicle routing and fleet sizing for Flash Delivery services.
First, the Flash Delivery Problem is formally defined and modeled as a Markov Decision Process. This serves as the basis for the dissertation's research and subsequent investigations. The thesis then proposes a novel routing algorithm for Flash Deliveries from multiple depots, which effectively handles multiple depots for order pick-up and dynamically determines the optimal depot for each order. The depots are distributed within the city, for example, using existing stores, this differs from other logistical processes using large warehouses outside of the city. Additionally, this approach allows vehicles to visit depots to load additional orders before distributing their loaded ones, resulting in more agile planning. The scalability of this method is demonstrated in scenarios involving thousands of orders and tens of vehicles.
The proposed routing method is then extended to accommodate heterogeneous vehicles and heterogeneous modes of transportation. Experiments using a fleet featuring trucks and drones demonstrate that this approach serves more orders while requiring less total traveled distance compared to a state-of-the-art method for heterogeneous vehicles. The effects of fleet size and fleet composition between drones and trucks are also examined. More drones were able to deliver more requests at the cost of an increase in traveled distance.
The Fleet Sizing Problem represents the second major challenge addressed in this dissertation. The balance between having too many vehicles, which can be very expensive, and having too few, which leads to unmet promises and undelivered orders, is crucial for operational success. Typically, the Fleet Sizing Problem involves a fixed set of tasks with no flexibility in their execution. However, this thesis introduces a novel problem, adding flexibility in time through the allowance of slight delays in individual transportation tasks. We propose modeling and solving the novel problem as a Mixed Integer Linear Program. By incorporating this flexibility, the problem opens up a broader trade-off space between the required number of agents, traffic, and added delays. As a result, fleet sizes can be significantly decreased. To illustrate the practical application of this algorithm, a case study involving taxi rides in Manhattan is presented.
To conclude this thesis, fleet sizing is combined with the previously proposed routing methods for Flash Delivery, resulting in a novel approach. Our method groups individual delivery requests and generates optimized operational plans using a variation of the earlier proposed routing techniques. These plans are then used for fleet sizing. To assess the effectiveness of our approach, we compare it against applying routing and fleet sizing separately. The results clearly demonstrate the value of our proposed method.
Our experimental analysis is based on a real-world dataset provided by a Dutch retailer, allowing us to gain valuable insights into the design of Flash Delivery operations.
In summary, this thesis makes significant contributions to the operational optimization of Flash Delivery services by addressing key challenges in vehicle routing and fleet sizing. We propose novel methods to improve efficiency and effectiveness in planning Flash Delivery operations.","","en","doctoral thesis","","978-94-6384-533-5","","","","","","","","","Learning & Autonomous Control","","",""
"uuid:a6873511-f046-423a-8378-db2b1cf89c30","http://resolver.tudelft.nl/uuid:a6873511-f046-423a-8378-db2b1cf89c30","Global Techno-Economic Feasibility of Far Offshore Green Hydrogen Production towards 2050","Melles, Tycho (TU Delft Mechanical, Maritime and Materials Engineering)","Pruyn, J.F.J. (mentor); Gelling, J.L. (mentor); Delft University of Technology (degree granting institution)","2024","With space constraints onshore, strong renewable resources available far offshore
and growing green hydrogen demand, far offshore green hydrogen production
may be an attractive option. To assess this potential, a literature review was
conducted to identify the relevant technologies to be considered and suitable
modelling methods. Next, a mixed integer quadratically constraint programming
(MIQCP) optimization model was set up. The far offshore green hydrogen
supply chain was optimized for various scenarios with this model and the
results were analyzed. It was found that far offshore green hydrogen costs are
in the same order of magnitude as the costs of its alternatives. Far offshore
green hydrogen may be considered marginally competitive with these alternatives
from 2035 onwards in the analyzed scenarios when taking into account the
considerable advantages of far offshore production, such as avoidance of scarce
land usage in crowded areas and certain geopolitical considerations.","MIQCP; optimization; far offshore; green hydrogen; green FPSO; global; 2050; techno-economics; LCoH","en","master thesis","","","","","","","","2024-02-01","","","","Marine Technology | Maritime Operations and Management","",""
"uuid:8938dd1c-683f-49b5-a607-75fe8c4b6447","http://resolver.tudelft.nl/uuid:8938dd1c-683f-49b5-a607-75fe8c4b6447","Designing the Brain of an Intelligent Lunar Nano-rover","Bolscher, Thijs (TU Delft Aerospace Engineering)","Menicucci, A. (mentor); Rijlaarsdam, David (mentor); Guo, J. (graduation committee); Gaydadjiev, G. (graduation committee); Delft University of Technology (degree granting institution)","2024","As the Moon reemerges as a renewed fronteer in space exploration, the Lunar Zebro project proposes to deploy a swarm of miniature rovers for efficient lunar surface exploration. One of their goals is to leverage recent advancements in deep learning and AI-accelerating hardware, in conjunction with Commercial Off-The-Shelf technologies and the NewSpace movement, to enhance the autonomous capabilities of these nano-rovers. This research focuses on integrating AI-accelerating hardware within the stringent Size, Weight, and Power (SWaP) constraints of these lunar rovers. It evaluates the suitability of various hardware configurations. A Convolutional Neural Network for hazard detection was trained and tested on different devices and scenarios. Finally, the operational cycle of the rover was simulated and the constrained resources were tracked for the different design options.","On-Board Computing Architecture; Hazard Detection; low-SWaP Space Missions; Lunar Zebro; Swarming; AI-based FDIR; Autonomous Mission Planning","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:e22066bf-d0e2-482e-9bc6-b9d26b4ce054","http://resolver.tudelft.nl/uuid:e22066bf-d0e2-482e-9bc6-b9d26b4ce054","A Toolkit To Spark Interest In Engineering Among Young Adults","LIU, Fang-Yin (TU Delft Industrial Design Engineering)","Jaśkiewicz, T.J. (mentor); Kooijman, A. (mentor); Delft University of Technology (degree granting institution)","2024","This project aims to introduce engineering in a way that captures students' interest. In order to motivate studernts to try it out, instead of limited by their past experience. Therefore, expanding the original knowledge of engineering during the design ideation process becomes crucial. Beginning with the identification of factors contributing to the underrepresentation of female students in the field. Additionally, this study collaborates with Cities of Things Lab 010, which strives to incorporate citizens' opinions into the neighbourhood robot design process. Hosting the workshop and making robot development accessible to all citizens. For me, I narrowed down the scope to focus on students.
To address the research questions, I conducted a literature review and identified two gaps: limited research on gender learning in STEM for ages above 18 and a scarcity of studies on the male perspective. I conducted surveys to address these gaps. One focused on the educational robotics toolkit, utilizing experiences of female Industrial Design Engineering (IDE) bachelor students (aged 18 to 21).
The other survey aimed to understand the male perspective on the current situation in the engineering field. Involving both males and females in crafting the solution creates awareness of the responsibility that everyone plays a role in this situation. It is crucial to emphasize that this thesis does not aim to generate conflict between genders. Instead, its message has the ambition of shaping a world where everyone can choose what they want to do based on their interests, free from gender stereotypes. Furthermore, I defined the design goal of the toolkit based on this message.
The design goal of the toolkit is to make everyone feel involved and comfortable to share their opinion in the group discussion. Encouraging the incorporation of different viewpoints and getting inspired by other people’s ideas. Ultimately, broadens the existing original impression of robotics. To visualise the design goal and validate the final concept, I developed a prototype of an inspirational toolkit with fellow students mainly from the DP3 course in the IDE bachelor program. Since the group assignment of the DP3 course is to design a cleaning robot for the campus. Utilising this toolkit to inspire students in the early stages of robot design can have a positive impact on the design process. I conducted multiple user testings to improve the prototype, considering the interplay of aesthetics, form, user experience and assembly.
Final design HiveMind, I conducted user testing with a group of students to validate whether the after-use effect of the prototype aligns with the design goal. All participants agreed that they feel encouraged and comfortable expressing their ideas, and the toolkit helps them get on the same page. Furthermore, the toolkit improves group discussions in the early stages of the design process, especially when everyone in the group is not familiar with each other. The validation result shows that each participant has a more diverse impression of robots after using the toolkit. However, I observed that the shape of the robot they drew for the assignment still adheres to a traditional representation of how a robot should be. This suggests that future design recommendations could focus on the relationship between picture cognitive association, the impact of different game rules, and using the toolkit before or after hands-on activities.
The current state-of-the-art in Topology Optimisation (TO) for design-dependent pressure-actuated CMs (PACMs) relies heavily on linear models. The determination of design-dependent pressure loads involves employing the Darcy method, which integrates Darcy's law with the drainage term to obtain the pressure field. Subsequently, the finite element method (FEM) is used to transform the pressure field into consistent nodal forces. However, it is crucial to acknowledge that these linear models are only valid for small displacements.
This thesis introduces a novel approach by incorporating nonlinearities into the solid mechanics of the TO process for PACMs in conjunction with the Darcy method. Additionally, this work incorporates nonlinearities into the solid mechanics of the TO process for PA multi-material compliant mechanisms, presenting another novel method.
Four nonlinearities in the solid mechanics of PA soft robots may occur, two of which are addressed in this thesis: geometric nonlinearities and a hyperelastic material model. Geometric nonlinearities arise from large deformations caused by high applied pressures. The Neo-Hookean material model is implemented to describe the low-stiffness material accurately.
The TO of pressure-actuated (PA) soft robots is simulated using COMSOL, a commercial software program for multi-physics simulation. This research presents a detailed comparison between theoretical predictions and practical outcomes as realised in COMSOL. Furthermore, this thesis includes a case study validating the successful implementation of the new method, covering a PA inverter, a PA compliant gripper, a PA member of the Pneumatic Networks, and a PA multi-material compliant gripper. The obtained results indicate limitations on the allowable applied pressure loads for the mechanisms, specifically in the case of the PA member of the Pneumatic Networks and a PA multi-material-compliant gripper. However, the PA inverter and PA compliant gripper validate the expectation that incorporating a hyperelastic material model yields significantly different results than the linear elastic material model. Moreover, the TO with the hyperelastic material model can predict displacements more accurately than the linear TO, as the differences between the displacements obtained from the TO and the analysis align more closely.
The Wang method is investigated to observe its influence on the range of the applied pressure loads during the TO of PA soft robots. The Wang method employs an interpolation technique that interpolates between linear and nonlinear theories. In this approach, void elements are described using linear theory, while solid elements are characterised by nonlinear theory. This interpolation method is developed to address distorted elements during large displacements. It effectively extended the range of applied loads during the TO of structures. However, it is found that this method does not influence the range of the applied load during the TO of CMs.","Soft robots; Topology optimisation; nonlinearities; pressure-actuated","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Precision and Microsystems Engineering","",""
"uuid:e5f2d517-f492-4f85-9725-72e9884549b3","http://resolver.tudelft.nl/uuid:e5f2d517-f492-4f85-9725-72e9884549b3","Seismic acquisition analysis and design using multiple reflections","Revelo Obando, B.A. (TU Delft Applied Geophysics and Petrophysics)","Verschuur, D.J. (promotor); Wapenaar, C.P.A. (promotor); Blacquière, G. (promotor); Delft University of Technology (degree granting institution)","2024","Seismic survey design deals with determining the acquisition parameters that lead to the best possible imaging and characterization of the subsurface. The design of the survey is constrained by health, safety and environmental considerations and the available budget, seeking for a balance between quality and cost. Because seismic exploration is a widely used geophysical method for revealing underground resources, information about the subsurface is available in many areas. Therefore, it can potentially be used for purposes supplementary to exploration such as the monitoring of producing fields and fluids injection. However, the available budget for these purposes is usually lower than for exploration, and it becomes a priority to maximize the benefits derived from a potentially cheaper acquisition. In this thesis, we propose new methods for the analysis and design of seismic surveys that are based on previous knowledge from existing subsurface models and that aimto maximize image quality with the lowest acquisition efforts.","Seismic acquisition; Imaging; Inversion; Optimization","en","doctoral thesis","","978-94-6384-532-8","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:ba803901-4b24-4420-9d3f-f0db4ee5c680","http://resolver.tudelft.nl/uuid:ba803901-4b24-4420-9d3f-f0db4ee5c680","Beyond the Lab: Challenges to Detect Parkinson’s Disease Symptoms in Remote Smartwatch Data","Schut, Inge (TU Delft Mechanical, Maritime and Materials Engineering)","Schouten, A.C. (mentor); Delft University of Technology (degree granting institution)","2024","Parkinson's Disease (PD) is a neurodegenerative disorder with four cardinal motor symptoms: bradykinesia, tremor, rigidity, and postural instability. Adaptive Deep Brain Stimulation (aDBS) is a promising treatment for PD that provides stimulation based on the expression of PD symptoms, improving effectiveness and reducing side effects compared to continuous DBS. Smartwatches can facilitate aDBS by enabling continuous detection of tremor and bradykinesia. However, for bradykinesia detection, existing studies using smartwatch data from PD patients' natural environment were limited in study duration and sample size. To address this, the current study collected smartwatch data for up to seven months in PD patients' natural environments. From 22 PD patients, the smartwatch data was pre-processed, features were extracted and analysed, and a Variational Autoencoder (VAE) was trained to develop a bradykinesia detection model. However, the VAE could only learn from frequency-domain inputs and not from time-domain input data after current pre-processing methods. Limitations were identified in data quantity, distribution, and quality, including low-frequency artefacts and noise. Despite these limitations, feature analysis indicated that the data set contains valuable information about PD motor symptoms. The results of the feature analysis and VAE training on frequency-domain inputs suggest that, after addressing limitations in data quantity and quality, it could be possible to train the VAE using smartwatch data from PD patients' natural environments. In conclusion, although a bradykinesia model was not successfully developed, this study demonstrated the required steps for training the VAE and laid the groundwork for future studies to develop a bradykinesia detection model.","","en","master thesis","","","","","","","","","","","","Mechanical Engineering | BioMechanical Design","",""
"uuid:e92fbd81-5b7e-4d40-8c22-75f56486639e","http://resolver.tudelft.nl/uuid:e92fbd81-5b7e-4d40-8c22-75f56486639e","Anaerobic membrane bioreactor (AnMBR) for the treatment of lipid-rich dairy wastewater","Szabo Corbacho, M. (TU Delft Sanitary Engineering)","van Lier, J.B. (promotor); Hernandez, Hector Garcia (promotor); Delft University of Technology (degree granting institution)","2024","The ongoing growth of the global population has led to increased resource consumption, particularly in the realm of water resources, resulting in potential shortages and environmental concerns. The surge in industrialization has intensified the demand for freshwater, consequently causing significant contamination of global water sources through the discharge of industrial wastewater. This wastewater contains harmful contaminants, such as heavy metals and organic compounds, which pose significant threats to both aquatic ecosystems and human health (Corcoran, 2010). To effectively address this issue, it is imperative to strengthen regulatory measures, promote industrialized initiatives for wastewater reduction and treatment, and foster technological
advancements in wastewater management.
Lipids within wastewater systems present both opportunities and challenges. Their high energy content holds promise for bioenergy conversion, yet they can also disrupt anaerobic wastewater treatment processes. Consequently, it is often advisable to extract lipids before commencing biological treatment processes (Alves et al., 2009). Lipids are commonly referred to as fats, oils, and grease (FOG) (Cavaleiro et al., 2008). At the core of FOG composition are triglycerides, formed through the esterification of glycerol with long-chain fatty acids (LCFA) (Alves et al., 2009). Within lipid-rich wastewaters, the prevailing LCFAs identified include palmitic acid (C16:0) and oleic acid (C18:1), as highlighted by Hwu et al. (1996). Anaerobic digestion (AD) plays a central role in advancing various sustainable development objectives by seamlessly integrating energy and resource recovery from organic residues and wastewater, all while effectively managing pollution. AD's ability to produce renewable gaseous energy, recycle essential nutrients, and minimize excess sludge production, combined with an enhanced understanding of microbiology and ecophysiology, has propelled AD technologies to the forefront. These technologies now serve as environmentally friendly treatment options for a wide range of wastes and wastewaters, as evidenced by their widespread adoption at the global level (van Lier et al., 2020). Sustainable and efficient conversion of these waste lipids into methane within anaerobic reactors is met with impediments including adsorption, sludge flotation, washout, and inhibition. However, these complications can be circumvented through feeding protocols, optimized mixing, and adept solid separation methods, underpinned by cutting-edge reactor designs and operational methodologies. More recently, developments such as the anaerobic membrane bioreactor (AnMBR) and flotation-based bioreactors have emerged as solutions tailored for lipid-intensive wastewater treatment (Cavaleiro et. al., 2008). AnMBR, a nexus of anaerobic digestion and membrane filtration, has proven particularly adept for dairy wastewater treatment. It alleviates the challenges tied to gravity-based separation, yielding effluents devoid of suspended solids and of superior quality (Judd, 201).
The central focus of this research centered on the assessment of solids retention time (SRT) and its critical role in the operational parameters of AnMBR. This was accomplished by studying sludge filterability and membrane filtration performance. Additionally, we investigated how the acclimatization of biomass impacted the transformation of longchain fatty acids (LCFA) in lipid-rich wastewater. Initial evaluations emphasized the role of SRT on AnMBR efficiency during the treatment of synthetic dairy wastewater laden with lipids. Employing two distinct AnMBR configurations with SRTs of 20 and 40 days, both systems manifested approximately 99%efficiency in waste removal at an organic loading rate of 4.7 g COD L-1 d-1. Significantly,lipid sedimentation was absent, facilitating their continued anaerobic degradation. LCFAaccumulation was minimal in both systems, with the 40-day SRT configuration showing slightly enhanced biological conversion and stability. Subsequently, the study delved into the effects of SRT on the filtration efficacy of AnMBR using lipid-rich synthetic dairy wastewater. When confronted with 40-day SRT, the system encountered elevated pressures and resistances, presumably due to escalated contaminant levels, including fats, oils, and LCFAs. While both systems showcased analogous filterability, the 20-day configuration exhibited superior membrane performance, suggesting potential membrane operational refinements for the 40-day SRT. Lastly, the influence of LCFA on anaerobic sludge processes was investigated. Trialing three distinct sludge samples—two lipid-acclimated and one non-acclimated—they were exposed to varying oleic and palmitic acid concentrations, ranging between 50 to 600 mg COD/L. Oleic acid showed superior degradation capabilities compared to palmitic acid across all samples, with heightened methane production. Lipid-acclimated sludges demonstrated augmented LCFA degradation potential. However, upon reaching LCFA concentrations beyond 400 mg/L, degradation of both acids into intermediate products was inhibited, albeit without affecting methane production. Intriguingly, specific bacterial taxonomies associated with LCFA degradation were identified in lipid-acclimated sludge samples, underscoring the potential of sludge adaptation strategies in enhancing anaerobic treatment of lipid-rich effluents.
In this doctoral research, we elucidated the prospects and challenges associated with the utilization of AnMBR for treating lipid-rich dairy wastewater. We highlighted the critical importance of Solid Retention Time (SRT), a key operational parameter that exerts a profound influence on both the biological and membrane aspects of the system.
Furthermore, our study underscored the paramount role played by the two most prevalent Long-Chain Fatty Acids (LCFAs), namely oleic and palmitic acid, within the domain of anaerobic digestion.","","en","doctoral thesis","","978-90-73445-58-1","","","","","","","","","Sanitary Engineering","","",""
"uuid:751c0e04-5f8a-44d3-9e7e-f175008e9346","http://resolver.tudelft.nl/uuid:751c0e04-5f8a-44d3-9e7e-f175008e9346","Spatial variability in dike stability assessments","van der Burg, Lisa (TU Delft Civil Engineering & Geosciences)","van den Eijnden, A.P. (mentor); Lanzafame, R.C. (graduation committee); Kindermann, P.E. (mentor); Tigchelaar, Jan (mentor); Delft University of Technology (degree granting institution)","2024","The safety of the Dutch dikes depends on various failure mechanisms. Macro stability, a geotechnical failure mechanism, is highly affected by differences in soil strength because the sliding plane propagates through areas of least resistance. The variations in soil properties in space, also known as spatial
variability, are caused by geological processes and determine the locations of weaker zones in a dike. This highlights the importance of incorporating spatial variability into dike stability assessments.
The approach to incorporate spatial variability in the official Dutch assessment framework (WBI2017) relies on various assumptions. It assumes complete local variance reduction and neglects that the failure mechanism propagates through the weaker zones, leading to a mean strength reduction. Moreover, it assumes a default value for the ratio between local and regional variance α = 0.75, which lacks empirical evidence. Another method to incorporate spatial variability in stability calculations is the Random Finite Element Method (RFEM). This probabilistic technique models strong and weak zones through random fields. However, the main drawback is its considerable computation time, making it impractical to use for the assessment of the hundreds of kilometers of dikes in the Netherlands.
To address these issues, this research answers the question: What is an effective approach for incorporating spatial variability in soil into dike stability calculations? The study is divided into two parts: a data analysis and the creation of an RFEM model.
The first part investigated national and regional spatial correlations using variograms. The study found that the local spatial variance cannot be analyzed with variograms based on the national dataset. This is because the variograms average the variance in the local data due to their large scale. Investigating
local variability requires local data with a high enough density and accuracy in the research area.
In the second part, the inclusion of spatial variability was studied for a case study dike using RFEM, which is part of dike trajectory 34-2, located between Willemstad and Noordschans. The research highlighted two differences between assumptions made by RFEM and the WBI2017 method: (1) the
inclusion of statistical uncertainty and (2) the use of different stress components in calculating the undrained shear stress. The results of the different methods can only be compared if these differences are accounted for. Furthermore, the study found that using a probabilistic calculation with α = 0.8 better fits the results of the realistic RFEM model of the case study dike, particularly in the lower tail of the distribution of the results, compared to the default value of α = 0.75. Therefore, it can be concluded that α = 0.8 leads to a more realistic approximation of the probability of failure of this cross-section.
To investigate the importance of this finding, an assessment was carried out following the guidelines of WBI2017 but with α = 0.8. This showed that the probability of failure for dike trajectory 34-2 was reduced by 39.72% but that the safety category of the dike trajectory (for macro stability) remains unchanged.
Therefore, the answer to the research question is that when considering the computational requirements of RFEM, it is more effective to keep using the WBI2017 approach of implementing spatial variability into the input parameters of dike stability calculations with α = 0.75.
These findings are relevant as they validate the use of the current method with the available data. The study used different approaches for incorporating spatial variability in stability calculations and provides valuable insights for future research.","RFEM; SHANSEP; Macro-stability; WBI2017; Variogram","en","master thesis","","","","","","","","","","","","Geo-Engineering","",""
"uuid:28542c6f-1e32-4beb-87eb-d4080ed4647d","http://resolver.tudelft.nl/uuid:28542c6f-1e32-4beb-87eb-d4080ed4647d","VoNA The Visualisation of Neuronal Activation: To observe and shape electrode-generated outputs for electrical stimulation in the brain using a Finite Element Model","van Lith, Niels (TU Delft Mechanical, Maritime and Materials Engineering)","Lopes Marta da Costa, T.M. (mentor); Remis, R.F. (graduation committee); Delft University of Technology (degree granting institution)","2024","The development of neural prostheses, especially those directly targeting the brain, requires extensive research and modelling before clinical trials can be performed. Currently, the resolution of artificial vision is not sufficient for everyday tasks. By studying the expected spatial extent of stimulation, we aim to provide insights to researchers that can be used to improve the resolution of artificial vision. The goal of this MSc thesis was to visualise the shape and intensity of electric fields in the cortex as a response to intracortical microelectrode stimulation to observe the expected regions of neuronal activation considering electrode design parameters. To do this, parameters that can influence the generated electric field and the regions of activated tissue have been defined. Implementing these parameters in a Finite Element Model (FEM) allows the computation of the generated electric field in 3D of a stimulating electrode to observe the spatial extent of activated tissue. The spatial extent of activated tissue can be estimated using simplified methods such as the activating function (AF) or current density threshold. The result is a parameterised framework that creates a Visualisation of Neuronal Activation (VoNA) that can be used to assess activated tissue regions for varying scenarios by defining material properties and dimensions of the model, and allows for the adjustment of the stimulation configuration, electrode contact spacing, customisation of electrode size and modulation of stimulation current. It enables the user to tune the model settings towards their specific needs and explore the possibilities by visualising the results from different angles by defining subsets of the entire solution. In line with expectations, the presented models show that the model parameters can influence factors such as the generated electric field, the current density and electric potential, which are indicators of neuronal activation. The findings support the hypothesis that these parameters should be considered during electrode design to achieve accurate stimulation.","FEM; Activating Function; Parameterised model; COMSOL; Intracortical; Neuronal activiy; spatial extent of stimulation","en","master thesis","","","","","","","","","","","","Biomedical Engineering","",""
"uuid:25537b5d-3ecb-4b08-8cf3-723e437d8738","http://resolver.tudelft.nl/uuid:25537b5d-3ecb-4b08-8cf3-723e437d8738","Optimization of Interplant Water Reuse in Industrial Parks: Considering Water Treatment Systems","Koldewijn, Niels (TU Delft Civil Engineering & Geosciences)","Spanjers, H. (mentor); Rietveld, L.C. (graduation committee); Korevaar, G. (graduation committee); Garzón Díaz, J.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Reusing water is a crucial part of the solution for addressing the growing concern regarding the risk of water scarcity in industrialized and urbanized areas. This study introduces a tool for the design of water networks, focusing on water reuse in industrial parks. Utilizing a mixed-integer nonlinear programming (MINLP) model developed earlier, this tool is the first in water network design models that operates with open-source software, while considering water treatment systems and multiple constituents. A literature study is conducted to discover shortcomings in water network design models and to find a foundational model to use to develop the tool. The developed tool creates a water network based on the optimization of the costs of water obtained from water sources, the costs of treatment systems, and optionally the piping costs. The treatment systems are used to regenerate the water for reuse in industrial plants and to meet environmental discharge limits. The tool develops local optimal solutions as an output. Additionally, this study is the first to integrate a water treatment systems database into a water network design model. However, this database needs to be expanded before it is usable. This study demonstrates the tool through three case studies.","Interplant Water Reuse; Water Treatment System; Industrial Symbiosis; Optimization Modeling; Mixed-Integer Nonlinear Programming","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:cfa86046-384d-4cf4-bfa1-c25b6844ab7e","http://resolver.tudelft.nl/uuid:cfa86046-384d-4cf4-bfa1-c25b6844ab7e","Potential Impacts of Transit-Shared Bike Integration on Equity in Job Accessibility: A Case Study in the Amsterdam Transport Region","Wang, Quanyi (TU Delft Civil Engineering & Geosciences; TU Delft Transport and Planning)","van Oort, N. (mentor); Bruno, M. (mentor); Pel, A.J. (mentor); Voerknecht, Hans (graduation committee); Delft University of Technology (degree granting institution)","2024","Travelling to work is one of the essential activities in individuals’ daily lives. However, commuters who depend on public transport often face significant challenges in accessing job opportunities, resulting in transport-related social exclusion risks. In recent years, shared mobility services have gained popularity as a solution, offering greater flexibility in first/last-mile segments of multimodal trips. These services have promising potential to improve accessibility for those who rely on public transport, thereby addressing issues of accessibility inequity. Such an intervention aligns well with the unique Dutch cycling culture, where cycling already accounts for a substantial portion of transit journeys. However, limited bike availability at the egress side diminishes the utilization of bikes for the last mile of a trip. To address this issue, integrating shared bikes with transit as an egress mode could be an effective intervention.
This thesis conducted a ”what-if analysis” in the Amsterdam Transport Region to investigate the impacts on job accessibility for different commuters and the equity of the whole transportation system if shared bikes are provided at transit stations as the egress mode. The results highlight the considerable potential of this integration in improving job accessibility and promoting social equity.
Implications drawn from the analysis provide valuable insights. Statistically, groups without car access can benefit more than groups with car access from integrating transit and shared bikes, but benefits might favour high-income groups. Geographically, accessibility improvements are mainly distributed to commuters living next to transit stations, while equity improvements are concentrated in areas with dense and developed public transport systems. Additionally, commuters living close to transit stations are more likely to contribute significantly to the overall accessibility deficiency, even though they have convenient first-mile segments. These implications guide policymakers in prioritizing interventions for targeted groups or regions, and facilitating the creation of a more equitable transportation system.
A systematic approach was used to determine which type of motion compensation device is best suited for this operation. Numerical models were set up in the commercial software OrcaFlex, where a wide range of different motion compensation types were tested. These motion compensation systems vary in the amount of degrees of freedom compensated and the actuation method. The actuation methods are passively actuated gas springs and position-based motion control using hydraulic actuators.
First, it was identified what combination of degrees of freedom and actuation method is best suitable. This was determined by performing a regular wave analysis and comparing the performances of the proposed motion compensation systems. The performance was indicated by the ability of the motion compensation system to control the weight on bit, reduce the maximum stress as well as the fatigue damage accumulation in the drill string. From this analysis it was concluded that a passive actuated concept that compensates for the heave, roll, and pitch of the vessel is the most effective scheme.
The optimal type of motion compensation system was then pursued by designing two different systems capable of compensating for the heave, roll, and pitch motion of the vessel. The first, relatively simple, type consists of a vertical gas spring and a universal joint where the drill rig can rotate freely. The other type is a passive variant of the Barge Master platform motion compensation system. This second concept was designed using a multi-objective optimization algorithm, the NSGA-II algorithm. The difference between these two systems is that the platform concept has rotational stiffness, while the simple type is free in this degree of freedom.
It was finally concluded that both concepts are viable solutions, and that both systems represent a motion compensation system that compensates for the heave, roll, and pitch motion of the vessel. The performance regarding the indicators is very similar, therefore choosing one of the concepts would come down to the other advantages and disadvantages of the concepts.
However, in predictive simulations of gait, hyperextension of the knee during stance phase is often encountered. This limits their applicability in research into running-related injuries. It is unclear what causes these unrealistic kinematics, with various studies coming to conflicting conclusions.
This study aims to identify the cause of knee hyperextension in predictive models of running and subsequently, to determine the essential modeling elements for accurately simulating stance knee flexion.
A structured analysis was conducted to investigate the potential impact of the model components within the predictive simulation framework. This framework was divided into four main categories: the objective function, the musculoskeletal (MSK) model, the foot contact model, and the controller. The analysis resulted in numerous hypotheses regarding the element that might be responsible for the simulation of realistic knee kinematics. SCONE, an open-source package for neuromusculoskeletal predictive simulation, was used to test the effect of each hypothesis on the simulated running kinematics. The simulation outcomes were compared to experimental data to assess possible improvements.
The results demonstrate that, in contrast to previous literature, adaptations to the objective function, the MSK model, and the foot contact model have negligible effects on predicted running kinematics. This leads to the conclusion that the controller is essential to focus on when improving knee kinematics. Due to time constraints, multiphase control could not be implemented. Therefore, the exact reflex pathways and phase transitions should be further investigated for the predictive simulation of running before implementation is possible.","predictive simulation; Neuromuscular modeling; Running Gait","en","master thesis","","","","","","","","","","","","Biomedical Engineering","",""
"uuid:e3f2d8a8-048f-49a0-ac2f-347f224c55e4","http://resolver.tudelft.nl/uuid:e3f2d8a8-048f-49a0-ac2f-347f224c55e4","Indoor Localization for Efficient Bike-Sharing Management","Visser, Berend (TU Delft Electrical Engineering, Mathematics and Computer Science)","Venkatesha Prasad, Ranga Rao (mentor); Song, Q. (graduation committee); Willemsen, G.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","In response to the growing demand for sustainable transportation solutions, bike-sharing systems have gained prominence in supporting an eco-friendly means of commuting. Within this landscape, Skopei, a forward-thinking company specializing in innovative sharing propositions, has developed a smart bike lock capable of autonomous rentals and returns. This master’s thesis delves into the application of radio frequency-based distance measurements to create an indoor positioning system for the efficient management of bike storage. Specifically, the system is designed to determine whether bikes have been correctly parked at docking locations, enabling users to conclude their rentals autonomously. The architecture of this system uses a network of anchor nodes (known-location routers) that should ascertain the positions of mobile nodes (bikes) within the bicycle storage area. Notably, the solution developed in this thesis employs sophisticated distance measurement techniques, including frequency hopping and phase shift analysis. By finding the amplitude and phase shift over multiple frequencies, we can find the channel impulse response and estimate the distance using machine learning. We employ a novel Multi-layer Perceptron neural network regressor to improve the accuracy in the presence of complex environmental factors in bike storage environments. In the bike storage test case, we achieved a mean absolute error in position estimation of 1.68m compared to 3.80m of a naive approach. We improved the parking state classification from 75.99% of a naive approach to 98.09% with our machine-learning-based approach. This thesis underscores the importance of cutting-edge distance measurement methods and real world field studies in advancing indoor positioning systems, specifically for smart bike storage management. By bridging the gap between technology and sustainable transportation, this work aims to make urban bike-sharing systems more scalable, efficient, user-friendly, and environmentally conscious.","Indoor positioning; Multilayer Perceptron; Machine Learning (ML); Localization","en","master thesis","","","","","","","","2026-01-22","","","","Electrical Engineering | Embedded Systems","",""
"uuid:fe19a6f9-35bb-477f-a206-edd7ba6ae43a","http://resolver.tudelft.nl/uuid:fe19a6f9-35bb-477f-a206-edd7ba6ae43a","Experimental Validation of Model-Based Control Methods for Shape Regulation in Soft Robots","Bhatti, Ghanishtha (TU Delft Electrical Engineering, Mathematics and Computer Science)","Della Santina, C. (mentor); Kober, J. (graduation committee); Pustina, P. (graduation committee); Delft University of Technology (degree granting institution)","2024","Soft robots are characterized by compliant elements that introduce heightened kinematic complexity compared to their rigid counterparts. Such systems, with infinite degrees of freedom, are inherently underactuated, making precise real-time shape regulation a challenging task. Model-based controllers, utilizing tractable reduced-order modelling methods, have emerged as promising solutions. However, practical implementations of these methods often rely on fully-actuated approximations, overlooking the underactuated nature of these continuum structures. In this study, we aim to experimentally validate model-based controllers that explicitly account for underactuation, surpassing the theoretical feasibility demonstrated in simulation. These controllers incorporate gravity cancellation and compliance compensation using the dynamic model of the robot to achieve superior real-time shape regulation compared to conventional PD/PID controllers. To facilitate this experimental validation, we have built a multi-segment soft robot research platform that includes a passively actuated segment, allowing for the utilization of both actuated and unactuated degrees of freedom in the control feedback loop. Through rigorous experimentation, we provide comprehensive evidence of the efficacy of this class of model-based controllers in controlling unconventionally actuated robotic systems. Consequently, our work bridges the gap between theory and practice, resulting in a practical real-time shape regulation framework that is adaptable to a vast variety of soft robotic systems.","Soft Robotics; Shape Regulation; Model-based Control; Experimental validation","en","master thesis","","","","","","","","","","","","Electrical Engineering | Embedded Systems","",""
"uuid:0f293d68-e98a-46ca-9561-51d47862fd60","http://resolver.tudelft.nl/uuid:0f293d68-e98a-46ca-9561-51d47862fd60","Designing Expressive Movements for Non-Anthropomorphic Hotel Restaurant Service Robots","Lee, Hyunmin (TU Delft Industrial Design Engineering)","Cila, N. (mentor); Rozendaal, M.C. (mentor); Koerten, Klaas (graduation committee); Delft University of Technology (degree granting institution)","2024","The hospitality industry, struggling with significant staff shortages, has increasingly turned to service robots as a solution. However, the prevalent service robot’s design with anthropomorphic appearance is considered inharmonious with the fine-dining restaurant ambiance and may harm the guests’ perception of the service. An alternative approach is exemplified by Rober, which adopts a design resembling a traditional cart. The non-anthropomorphic design offers flexibility, economic efficiency, and enhanced acceptability in hospitality settings. However, it also raises challenges in expressing intentions that are typically conveyed through human non-verbal cues. Consequently, the movement quality of service robots becomes a critical area of design to facilitate nuanced human-robot interaction (HRI) in hotel restaurant contexts.
The research focused on two main questions: how to design robot movement to facilitate essential interaction and collaboration qualities during dining experiences, and how to craft these movements using a dramaturgic performative approach. The project employed methodologies like speculative enactment and Extended Reality (XR) experiments to explore and evaluate robot movements. These methods allowed for creative ideation and assessments of the robot’s movements in simulated dining scenarios.
The project’s findings revealed that specific robot movements, including refined presence, prompted actions, and engaging addresses, significantly enhance the experience of guests, staff, and managers of the hotel restaurant. The robot’s role was envisioned as an ‘Ensemblist,’ a term encapsulating its function as an integral yet unobtrusive participant in the fine dining scene. This role demands the robot be ‘response-able,’ adapting to the fine dining rhythm. Furthermore, the project’s performative approach illuminated methods to design the robot’s movement as expressively meaningful and contextually appropriate. Methodological reflections revealed the effectiveness of speculative enactment and XR experiments in capturing the complexities of human-robot interactions, though suggesting future improvements in prototype fidelity, participant diversity, and advanced data treatment.
This project contributes to the field of HRI in hospitality, bridging theoretical concepts with practical applications. It lays the groundwork for future research in service robot design, emphasizing the need for nuanced interaction designs that resonate with human users in the hospitality sector.","Human-Robot Interaction; Human-Agent Collaboration; Hospitality; Speculative Design; Expressive Agents; Movement; Design for Interaction; Performativity","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:50782ab3-445a-4823-b636-b8c432ddefc6","http://resolver.tudelft.nl/uuid:50782ab3-445a-4823-b636-b8c432ddefc6","Engine Shop Visit Scheduling: A Reinforcement Learning Optimization Approach","Winckler Musskopf, Nicolas (TU Delft Aerospace Engineering)","Santos, Bruno F. (mentor); Delft University of Technology (degree granting institution)","2024","The scheduling of engine shop visits quickly becomes a complex problem to solve as the number of aircraft and engines increases. In recent times, different approaches have been used to tackle this problem and optimize schedules, reducing costs and increasing revenue. This paper formulates the ESV scheduling problem as a Markov Decision Process and develops a reinforcement learning model that includes parameters such as engine performance and life limited parts status, maintenance constraints, and temporal factors. A prioritization algorithm is presented to optimize the learning process and allow for the scheduling of larger fleets. The results show a slight better performance in comparison to a greedy policy when evaluating aircraft availability, flexibility to the initial parameters and reduction in use of spare engines. On the other hand, the reinforcement learning provided lower scores and higher number of removals of aircraft from operations. In conclusion, the methodology proved that reinforcement learning is a viably way to optimize the ESV scheduling process, however a fine tuning of parameters might be necessary to approximate scores to a real revenue and cost relation, and reduce the number of aircraft interventions.","Engine MRO; Engine Shop Visit; Scheduling optimization; Reinforcement Learning; aircraft engine","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:78214c62-6af2-4a51-adb1-6ce253258ead","http://resolver.tudelft.nl/uuid:78214c62-6af2-4a51-adb1-6ce253258ead","Soundstorm: Collaborative Ideation for Sound-Driven Design","Moleman, Rob (TU Delft Industrial Design Engineering; TU Delft Design Aesthetics)","Ozcan Vieira, E. (mentor); Delle Monache, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","Product sounds are important in our interactions with them. The temporal and context-dependent nature of sound makes it difficult to design them. There is a semantic gap between how we talk about sound and how it is embodied. Sound-driven design aims to improve this in two ways. It proposes a human-centered design approach, focusing on designing for the listening experience instead of purely the sound. Secondly, it proposes a collaborative approach, iteratively designing the listening experience with all stakeholders throughout the project.
The four stakeholders of sound-driven design work and design with sounds in different ways. Sound designers are brought in late into a project and work on sound solitarily. They are experts at bridging semantic gaps. Acoustic engineers are solution-oriented and think of sound in terms of noise elimination. Design researchers are experts in guiding design processes and incorporating user needs but are ill-equipped for sound. Expert users are well attuned to the sounds of their context, which is vital information for sound-driven design.
During group ideation, participants use generative session methods to generate solutions to a design problem. If this collaboration is managed effectively, a group outperforms its members. Generated ideas are larger in quantity, quality, variety, and originality. During idea generation, participants use their creative cognition to generate ideas. The dual pathways model of creativity states that creative cognition is the result of persistence and flexibility in thought. These two cognitive processes can be primed to enhance creativity.
Based on this theory I designed Soundstorm, a quick and collaborative card game. Players take turns making product sounds based on randomized prompts. It should be played before starting a generative session, and positively influences its outcomes. Soundstorm is meant to improve creative cognition by priming the persistence and flexible cognitive process. Soundstorm allows players to practice vocal expressions. Playing a collaborative game increases social cohesion.
Soundstorm was validated using a protocol study (n=18), in which 3 groups played a game before a brainstorm, and 3 did not. There was no increase in the number of ideas generated. There is an increase in iteration for the Soundstorm group, but the effect was not significant.
Future research into sound-driven design ideation should explore the fundamentals of sonic and verbal generative methods. Furthermore, sound-driven design should be applied in a collaborative project where problem and solution are allowed to coevolve over multiple iterations.
The research encompasses a comprehensive analysis of heat pump models, emphasizing their role in space heating, space cooling, and domestic hot water functions. Two specific models are chosen for Coefficient of Performance (COP) and Energy Efficiency Ratio (EER) calculations. These models, along with the utilization of the nPro tool, lay the foundation for integrating heat pump systems with PV production and battery storage in residential buildings.
The study successfully integrates the model of the battery’s performance and the overall grid-connected energy system. Employing a mathematical modeling approach, each component is systematically incorporated into the system, including the previously developed heat pump model. This integration, coupled with the Alternating Current (AC) output of the PVMD toolbox and the battery, establishes the groundwork for subsequent economic and performance analyses of the system.
The study systematically selects various locations with different environmental conditions such as Equivalent Sun Hours (ESH) and average ambient temperature to analyze the economic aspect by checking the Net Present Cost (NPC) and performance aspects by checking Self Consumption Ratio (SCR) and Self Sufficiency Ratio (SSR) of the integration model. The findings emphasize the economic viability of heat pump investments in cities with distinct heating and cooling demands. It has been demonstrated that in colder cities where heating demand is predominant, heat pumps are economically attractive, resulting having heat pumps in optimal scenarios that give the minimum NPC in Amsterdam and Lisbon. Additionally, although the individual components of the system may seem cost-ineffective, their value is derived more from integration in milder cities where heating demand is dominant, resulting having heat pump and PV integrated for the optimal scenario for Lisbon. However, cities dominated by cooling demand face challenges in achieving financially optimal designs because the operational savings for cooling cannot be accurately included such as Cairo and Dakar. The research underscores the importance of considering various system factors, including initial investment costs and electricity tariffs, to achieve financially optimal sizing. As the initial cost of the battery decreases, battery technology becomes economically appealing for Lisbon and Dakar. Moreover, changes in the tariff prove economically favorable for integrating the battery system in Lisbon, Cairo, and Dakar.
This work contributes valuable insights to the field of renewable energy, providing practical solutions for the transition towards cleaner and more efficient residential energy systems.","Residential building; PV panels; Heat pump; Battery Energy Storage System (BESS); NPC","en","master thesis","","","","","","","","","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:73460c6d-e4e1-44fa-a107-98d0e0748962","http://resolver.tudelft.nl/uuid:73460c6d-e4e1-44fa-a107-98d0e0748962","Phase Recognition for Pulmonary Orientation Detection: Towards Automated Intraoperative Imaging Guidance","Doornbos, Marie-Claire (TU Delft Mechanical Engineering)","Cornelissen, Bart (graduation committee); Sadeghi, Amir-Hossein (mentor); Delft University of Technology (degree granting institution)","2024","Objective: This study introduces a novel deep-learning-based orientation recognition approach for detecting intraoperative lung orientation during robot-assisted anatomical resections, including lobectomy and segmentectomy. This method can potentially aid in anatomical structure identification, facilitate training and education, improve procedural efficiency, and enhance intraoperative imaging navigation. Methods: We developed a unique dataset encompassing various pulmonary procedures, being the first to report on recognition of intraoperative orientation. The TeCNO model, initially developed for laparoscopic cholecystectomies, was adapted for this study. Model performance was evaluated using accuracy, precision, recall, and F1-score, and we explored the influence of dataset composition, intraoperative factors such as 3D model presence, and visual impairments. Results: The model achieved an overall accuracy of 70%, indicating potential in recognizing lung orientation. High performance was achieved in recognizing non-surgical sequences, ‘Fissure’, and ‘Inferior’ views. ‘Posterior’ and ‘Anterior’ views showed inferior performance. Variability in performance was attributed to the heterogeneity of orientation transitions and increased complexity compared to more standardized procedures. The limited dataset size and imbalances in label distribution potentially impacted model performance. Conclusion: This study demonstrates the feasibility of applying phase recognition to detect orientation of the lung and exploring how the unique characteristics of our dataset affect model performance opposed to surgical phase recognition. The results suggest promising applications for intraoperative imaging guidance and automated adjustment of 3D models, particularly for complex orientations like the interlobar ‘Fissure view’. Future research should focus on enhancing model performance and assessing its clinical implementation in diverse surgical settings.","Artificial intelligence (AI); Phase Recognition; Orientation Recognition; Deep-Learning; Lung Lobectomy; Lung Segmentectomy","en","master thesis","","","","","","","","2024-04-01","","","","Technical Medicine","","51.91097039349741, 4.467856169530635"
"uuid:6d06a1d8-56b8-4234-8d02-4192721539af","http://resolver.tudelft.nl/uuid:6d06a1d8-56b8-4234-8d02-4192721539af","Benchmarking Neural Decoders: Benchmarking of Hardware-efficient Real-time Neural Decoding in Brain-computer Interfaces","Hueber, Paul (TU Delft Electrical Engineering, Mathematics and Computer Science)","Tömen, N. (mentor); Micheli, A. (graduation committee); van Gemert, J.C. (graduation committee); Marroquim, Ricardo (graduation committee); Delft University of Technology (degree granting institution)","2024","Designing processors for implantable closed-loop neuromodulation systems presents a formidable challenge owing to the constrained operational environment, which requires low latency and high energy efficacy. Previous benchmarks have provided limited insights into power consumption and latency. However, this study introduces algorithmic metrics that capture the potential and limitations of neural decoders for closed-loop intra-cortical brain-computer interfaces in the context of energy and hardware constraints. This study benchmarks common decoding methods for predicting a primate’s finger kinematics from the motor cortex and explores their suitability for low latency and high energy efficient neural decoding. The study found that ANN-based decoders provide superior decoding accuracy, requiring high latency and many operations to effectively decode neural signals. Spiking neural networks have emerged as a solution, bridging this gap by achieving competitive decoding performance within sub-10ms while utilizing a fraction of computational resources. These distinctive advantages of neuromorphic spiking neural networks make them highly suitable for the challenging closed-loop neural modulation environment. Their capacity to balance decoding accuracy and operational efficiency offers immense potential in reshaping the landscape of neural decoders, fostering greater understanding, and opening new frontiers in closed-loop intra-cortical human-machine interaction.","neural decoding; brain computer interfaces; closed-loop neuromodulation; spiking neural networks; neuromorphic computing","en","master thesis","","","","","","http://doi.org/10.36227/techrxiv.24523291","","2025-12-07","","","","Electrical Engineering","",""
"uuid:bdf55847-4d93-4bd9-bec6-13132a52a6d8","http://resolver.tudelft.nl/uuid:bdf55847-4d93-4bd9-bec6-13132a52a6d8","Dynamic loadability of cables in grids connected to offshore wind farms","Srivastava, Akshaj (TU Delft Electrical Engineering, Mathematics and Computer Science)","Ghaffarian Niasar, M. (mentor); Delft University of Technology (degree granting institution)","2024","Abstract:
As grids become more and more saturated due to addition of more renewable energy sources in the system, the power demand keeps on increasing. This puts a pressure on the electrical utilities especially the power cables transferring power from one voltage level to another. Therefore, prior investigation into the effect of dynamic loading of such power cables is required before implementing the system in the physical grid.
One such saturated system is the implementation of offshore wind farm cables and the utilities connected to it.
The objective of this study was to check the effect of the dynamic nature of power flow through the connected cable system. In order to get a quantified result the degradation of the cable is measured in terms of the lifetime consumption of the cables under different loading schemes.
The offshore grid connection from Ijmuiden ver area in the North sea operated by Tennet has been identified as a case study for explaining the results. The offshore platforms are connected to the converter station with the help of 3-core 66kV HVAC cables. The connection from the converter station to the onshore grid is with the help of 2 525kV 1-core HVDC cables. The setup has been modelled with the help of two separate models for both the AC and DC cable sross-sections respectively. The models were developed in MATLAB (analytical) and Comsol Multiphysics
5.0 (numerical) to check the effect of dynamic loading of the cables with the help of different current vs. time profiles. The temperature variation with time was checked for the two cable systems.The parameters of soil thermal resistivity and the burial depth were varied from (0.2[W/mK],1200[mm]) to (0.36[W/mK],1500[mm]).
For the AC cable, it was observed that the lifetime consumption increases on changing the soil thermal conductivity and burial depth from 0.36[W/mK],1500[mm] to 0.2[W/mK],1200[mm]. The percentage lifetime consumption is dependent on the time duration for which the cable has been overloaded with a current value greater than the steady state value of 310[A] corresponding to 90◦C. The worst case change between the two cases was observed as going from 0.4439% to 0.5295% per year.Thus, showing that prior investigation is needed before loading the cable with a certain current profile under a given scenario.
For the AC case, on overloading the cable with a current value about 1.2 times the normal value, the maximum percentage lifetime consumption observed was 0.6208%. For the DC cable, the lifetime consumption was measured in terms of the time to failure of the insulation. This parameter is a function of the radial thickness of the insulation from the conductor screen to the insulation. The time to failure increases as one moves away from the conductor screen. Greater insulation deterioration was found to happen with the burial depth and soil thermal conductivity being (1200[mm],0.2[W/mK]) as compared to the case (1500[mm],0.36[W/mK]).A reversal in the
trend of time to failure was observed when the cable was overloaded with a current value of 1.2 times the normal current. The worst case mean value of time to failure observed was 39.68[y] for the normal case.
Building on identified limitations in existing robotic grippers and automated systems, a novel gripper design is proposed. This design uniquely approaches grasping the peduncle of vine tomato trusses. Traditionally, trusses have been grasped by the peduncle with standard pinching grippers for pick and place operations. The proposed gripper in this paper grasps the truss with a hook around the peduncle, often optimally at the centre of mass, increasing the success rate of grasping, stability, and avoiding damage to the truss. Furthermore, it has a higher tolerance for detection errors, allowing for inaccurate positioning of the robotic system. A hook-gripper can successfully grasp a wider range of tomato varieties than a pinch gripper.
The hook, consisting of two fingers, allows for more stable lifting of the truss and can handle peduncles in hard-to-grasp positions, such as in a crate filled with tomatoes. In addition to increased reach capabilities, the hook-gripper also enables manipulations like dragging and pushing.
The study involved an iterative design process, prototyping, and rigorous testing of the gripper. Key features include a hook mechanism for secure grasping, enhanced mobility for reaching into cramped spaces like packed crates, and a delicate touch to prevent bruising or damaging the fruit. The research also integrates the gripper with advanced detection systems for precise and effective operation within automated setups.
Results from extensive testing demonstrate that the newly designed gripper not only improves the success rate of grasping and manipulating vine tomato trusses but also significantly reduces the risk of damage compared to conventional pinch grippers. Individual trusses can be grasped with great success.
Testing for the different positions showed an increased range of grasping position that resulted in a successful grip. In practical experiments, the gripper performed well, lifting trusses with ease. Other test results show that the position of the peduncle is of great importance for the success rate. Test results indicated an 80% success rate in grasping trusses positioned near the edges of the crate. Replaying waypoint with ""learning from demonstration"" improves the grasping of the trusses compared to existing detection possibilities, and that emptying a crate is a challenging task.
The specialized hook-gripper offers insights into a practical solution for picking and placing vine tomatoes using the peduncle. This thesis contributes to the field of agricultural robotics and facilitates a step towards future innovations in the automation of high-value crop handling. The study delves into hook-gripper design and actuation, crucial for optimal performance in robotic manipulation systems.
Our research aimed to investigate the underlying causes of this specific performance degradation and find solutions to mitigate this issue. We employed the YOLOv8 object detector and created datasets from clinical procedures recorded at Reinier de Graaf Hospital (RdGG) and Philips Best Campus, supplemented with publicly accessible images. An aggregated version of object detection metrics was created for multi-camera system evaluation. Through a series of experiments complemented by data visualization, we discovered that the performance degradation primarily stems from data distribution shifts in the feature space. Notably, the object detector trained on non-sensitive online images can generalize to unseen Cath Labs, outperforming the model trained on a procedure recording from a different Cath Lab. The detector trained on the online images achieved an mAP@0.5 of 0.517 on the RdGG dataset. Furthermore, by switching to the most suitable camera for each object, the multi-camera system can further improve detection performance significantly. An aggregated 1-camera mAP@0.5 of 0.679 is achieved for single-object classes on the RdGG dataset.
of sodium sulfate spherulites. We characterized the spherulites’ morphological evolution and chemical/structural composition using various microscopy techniques and Raman Spectroscopy. The study reveals that faceted crystals, during their morphological evolution, can transiently exhibit a spherulitic morphology before attaining their final shape. We demonstrate that adding bivalent ions to sulfate solutions can create the conditions required for the spherulitic growth of the crystal phase. We show how to obtain perfectly developed spherulites through an in-depth experimental investigation of ion concentrations, evaporation rate, and geometric constraints. Moreover, quantifying the growth conditions enables a precise understanding and facilitates a comprehensive discussion on a general approach for
cultivating spherulites through solvent evaporation that is imperative for innovative purposes.
The study starts with the introduction and problem statement (Chapter 1). This is followed by a discussion of theories on Resource-Based View, Dynamic Capability, Agglomeration and Entrepreneurial Ecosystem, Culture, and Multi-actor theory (Chapter 2). Such broad approach is taken to enable a theory-underpinned broad scan of empirical reality. In this chapter several hypotheses are formulated that will be investigated in the empirical chapters that focus on the firm level. Next, Chapter 3 discusses the problematic situations and opportunities in the ICT sector in Indonesia (sector-level study). Although the ICT sector is a fast-growing sector in Indonesia, one of the problematic situations is that Indonesia is still a net-importer of ICT, which draws attention to innovativeness of domestic firms. In addition, the disparity of ICT infrastructure within the country is relatively wide between the western and eastern regions. The sector-level study in Chapter 3 is followed by a discussion on a set of conditions of ICT innovativeness at the firm level, including specific internal management conditions, and external and entrepreneurial ecosystem conditions in Chapter 4. The empirical results in this chapter are derived from an e-survey among 260 ICT firms (mainly small- and medium-sized), spread over Indonesia, and from estimation of multiple regression models. The findings suggest that firm capabilities and external knowledge spillovers positively influence firm innovativeness only after having reached relatively high values, as indicated by a quadratic relation. Moreover, the country’s entrepreneurial culture faces a ‘strong power distance’ or hierarchy that needs to be transformed for developing innovation. Chapter 5 examines the development differences between the Jakarta area (core region) and the rest of Indonesia (non-core regions) and how each of the conditions influence innovativeness in these regions. The study in Chapter 5 indicates that core and non-core regions in the country show differences in the entrepreneurial ecosystem and firm capabilities in various aspects. In the non-core regions, the innovativeness relationships with the management conditions and entrepreneurial ecosystem seem weaker than those in the core region. The most pressing outcome for non-core regions is that non-core regions have relatively modest firm-internal capabilities but also small potentials in the entrepreneurial ecosystem. The non-core regions also need to expend more effort on increasing innovativeness in terms of ICT skills and manager cognitive capability. Next, through change strategy formulation and in-depth understanding of innovativeness based on the empirical findings in Chapters 3, 4 and 5, the design of innovation change strategies in the ICT sector in Indonesia is explained (Chapter 6). This chapter provides direction for a set of solutions following empirical analysis at the firm level in the ICT sector for the entire country and two different regions. Chapter 6 also presents the elaboration of collaborative policymaking to improve policy implementation in Indonesia’s ICT sector, including more attention for consultation and deliberation between stakeholders and for evaluation. Chapter 7 discusses suggestions for making the study transferable in practice and the key contributions of the study. Chapter 8 concludes the study with reflections on the whole PhD study and discussions of the limitations of the research and suggestions for future research.
Three key conclusions from the empirical part of the study can be mentioned as follows. First, compared to larger firms, small firms in Indonesia have to put extra effort into learning to increase innovativeness. In this regard, the study found some non-linear relations (mostly quadratic) in management capabilities, especially in the ICT skills. This situation calls for improvement of small firms’ management capabilities, in particular ICT skills combined with market-related skills. Second, a relatively weak positive influence of urban environment and somewhat stronger positive influence of clusters can be found in the study. For example, the study could support theoretical ideas of agglomeration advantages (e.g., benefits of knowledge spillovers in metropolitan areas). The findings confirm the positive influence of networks within clusters. As the third conclusion, firm innovativeness tends to have a non-linear relationship with FDI, suggesting increasing returns (benefits), despite firm limitation to use FDI opportunities fully. In addition, the study found that the core and non-core regions in Indonesia differ in most firm-internal conditions, including management and entrepreneurial ecosystem conditions. For instance, ICT skill level is much higher in the core region than that in the non-core regions.
The key scientific contribution of this PhD study is in extending general innovation theories with a partially densely populated developing country like Indonesia, characterised by low technological level and low innovativeness mainly among small firms. The study reveals the extent to which the phenomenon in the developing countries can confirm or refute what has been postulated for developed countries, for example, concerning ambitions to be innovative and power structure within firms. As the policy contribution, the study suggests a new (policy) approach to respond to the many challenges in Indonesia, namely, in improving policymaking concerning conditions for innovation. The related approach is collaborative policymaking, including all stakeholders involved, in particular those at the level of practical policy implementation, with more emphasis on consultation and deliberation between them. The study also suggests a new approach at the firm level referring to ‘co-creation of inventions with customers’, which is relatively new in innovation practice in Indonesia.
Further, some limitations are inevitable due to financial and time constraints during this PhD study, including survey tools and representation of particular regions (e.g., Papua), though attempts were made to overcome the limitations by interviewing practitioners and experts. The study provides a number of suggestions for future research, including: first, to tackle the reluctance of SMEs to act as respondents, future research may extend and complement the survey in this PhD study through other data collection techniques, e.g., via professional surveyor. Second, future research may consider conducting an in-depth survey and complement it with interviews to identify other important qualitative aspects that have remained beyond the study, for instance cultural influence in innovativeness. Third, to use an advanced model assessment technique, such as Structural Equation Modelling (SEM), to evaluate whether theoretical models, including complex interactions between influencing factors, are plausible when compared to observed data. Fourth, the use of agglomeration index to allow the evaluation of the intensity of spatial agglomeration in a single sector and make a comparative analysis among different sectors. Fifth, to obtain the outcome in improving management conditions through a cascading strategy because the cascades process allows the firm to overarch the strategy throughout the organisation and create a supporting strategy for the firm’s entire value chain of activities to ensure the execution of management change. And sixth, a recommendation for collaborative experimentation to identify best practice, e.g., in co-creation.
Overall, this PhD research fills the gaps of innovation studies in Indonesia such as the incomplete focus of existing studies that are limited to a specific region of Indonesia (i.e., western Indonesia) and the limited follow-up for policy solution in practice. To the best of our knowledge, this PhD study is one of the few studies that covers large regions of Indonesia focusing on ICT sectors and also proposes policy and management solutions.
The aim of this study is to advance the understanding of the drying shrinkage mechanism in AAMs, by considering the contribution of the pore size distribution and gel characteristics of AAMs. A detailed analysis is performed to identify the governing parameter related to the drying shrinkage mechanism. This is done by controlling the pore size distribution and total porosity at moment of exposure, while differences in the gel composition were obtained. Moreover, the impact of different mix design parameters of blended AAMs on drying shrinkage behaviour, weight loss, microstructural development, flexural and compressive strength are investigated. The selected mix design parameters in this study include slag-to-fly-ash ratio (1, 0.7 and 0.5), curing time (3, 7, 14 and 28 days) and Na2O wt.% content (4 and 5 wt.%).
Results from the study indicate that drying shrinkage in AAMs is influenced by factors beyond water loss, diverging from the observed correlation in PC. The study highlights important findings related to mix design parameters. In terms of the slag-to-fly-ash ratio, an increase in ground granulated blast furnace slag (GGBFS) content correlates with reduced drying shrinkage, weight loss, refinement of the pore structure and total porosity. Regarding curing time, prolonged curing durations lead to decreased drying shrinkage and weight loss, coupled with improved flexural and compressive strength. As for activator content, an increased amount of activator refines the pore structure, resulting in reduced total porosity, weight loss, and increased compressive strength. However, drying shrinkage remains relatively constant over the 56 days exposure.
Based on the starting point that the pore size distribution of selected samples at the moment of exposure to drying was controlled, it is suggested that gel characteristics, i.e. reaction products, rather than pore size distribution, govern the drying shrinkage phenomenon in AAMs. Comparative analyses underscore the influence of homogeneous reaction products, a higher atomic Ca/Si ratio and the availability of sodium and silicate from the activator. At the moment of exposure, the type of gel is more crucial than the quantity, as demonstrated by the sample with more reaction products exhibiting greater drying shrinkage in the analysis.
The drying shrinkage mechanism in AAMs is strongly correlated with microstructure and the nature of reaction products. The comprehensive results of this study suggest that the gel characteristics have an crucial role as a driving force in the mechanism of drying shrinkage. The study underscores the substantial influence of mix design parameters on drying shrinkage, offering valuable insights for the practical implementation of AAMs in construction. This research marks a significant step forward in enhancing our understanding of this complex phenomenon for AAMs.
The study provides several recommendations for future research, including extending the range of mix design parameters and curing times to evaluate the findings of this study, assessing the rate of reaction of mixtures and considering the impact of drying on the exposed pore structure. Furthermore, the application of N2 adsorption to detect the smaller range of pores in AAMs, the determination of the influence of internal relative humidity on drying shrinkage, and the investigation of cracking potential of AAMs related to drying shrinkage are also suggested.
Various Meso-level C-FRTP 3D printing methods and print heads have been developed and standardized, but more knowledge is needed of essential 'In-Nozzle' C-FRTP impregnation dynamics. During In-Nozzle impregnation, solid-dry fiber and molten Thermoplastic polymer matrix bond inside the print head before extrusion. This master thesis explores the challenges and potential solutions by conceptualizing a functional ’In-Nozzle’ impregnation extruder capable of extruding proper C-FRTP composites using FDM printing.
Initially, a theoretical framework is presented on melt impregnation dynamics and Interface adhesion, followed by experiments as validation. Based on the melt impregnation analysis observations, a limited permeability of Thermoplastic polymer melt is observed. These are primarily from the high viscosity of the thermoplastic materials (PLA) and the dense fibers. Applying an overflow of melt with extensive external pressure achieves a smoother and faster melt flow around the interface. Tensile strength experiments underscored the dependency on the exposure time and encapsulation of fibers by matrix and showed an increase in IFSS compared to the neat thermoplastic polymer. Further research is recommended to augment contact surfaces between fibers and the matrix. This research highlights the current challenges and lays the foundation for future advancements in C-FRTP 3D printing through in-nozzle impregnation, offering insights into improving material compatibility, impregnation quality, and interfacial bonding.","Multi-Material Additive Manufacturing; Continuous fibre-reinforced thermoplastics; In-nozzle impregnation","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Mechatronic System Design (MSD)","ME56035 ME-HTE/OM MSc Thesis",""
"uuid:17143757-2b39-4911-9bb6-cd58ac7af854","http://resolver.tudelft.nl/uuid:17143757-2b39-4911-9bb6-cd58ac7af854","Implementation of Vision Control in an Autonomous Food Processing Robot","Yildiz, Haydar (TU Delft Mechanical, Maritime and Materials Engineering)","Eisma, Y.B. (mentor); Wisse, M. (graduation committee); Bosma, Stijn (graduation committee); Delft University of Technology (degree granting institution)","2024","","Algorithm; Autonomous System; Vision; Food Industry; Robotics","en","master thesis","","","","","","","","2026-01-29","","","","Mechanical Engineering","",""
"uuid:fdc21856-e15f-4297-9f7d-a1a83653f049","http://resolver.tudelft.nl/uuid:fdc21856-e15f-4297-9f7d-a1a83653f049","Fatigue Assessment of Complex Riveted Connections: A study on old steel bridges using Advanced Finite Element Analysis","Reijers, Rico (TU Delft Civil Engineering & Geosciences; TU Delft Old - CITG Dept. Structural and Building Engineering)","Veljkovic, M. (mentor); Mohabeddine, A.I. (mentor); Langendijk, W.J.P. (mentor); Tankova, T. (graduation committee); den Besten, J.H. (graduation committee); Delft University of Technology (degree granting institution)","2024","Numerous traffic bridges have been constructed over the last 150 years. Because bridges are commonly built based on an expected lifetime of 75 to 100 years, a large quantity of bridges are reaching the end of their design lifetime, or even are far overdue. To ensure these bridges remain operational without experiencing catastrophic failures, they have to be recalculated, and if need be, repaired, strengthened or replaced. Particularly older bridges are commonly constructed utilizing rivets. Their often overly complex geometries, the fact that riveting has become largely obsolete as a construction process, and old bridges are commonly not design for fatigue loading, engineers regularly face significant challenges when reassessing such bridges.
While fatigue phenomena have been extensively investigated throughout the years, studies pertaining to the fatigue of riveted connections are relatively limited. The Eurocode on fatigue, EN-1993-1-9 includes only two detail categories. Additional guidelines, like RBK Steel expand upon these detail categories, but focus primarily on built-up beam cross-sections in riveted structures, rather than riveted connections. In order to attempt to more accurately assess the complex joints present in ancient steel bridges, this thesis attempts to answer the following question: What would be a suitable approach to model complex riveted joints and assess their fatigue life considering a balance between the level of complexity and applicability in design practice?
A literature study is performed to identify the different factors that affect the fatigue resistance of riveted connections, as well as to highlight several of the available methods to perform a fatigue assessment. Through the investigation of experimental studies complemented with Finite Element (FE) Analyses, a design methodology for a full scale riveted model is drawn up, and finally a FE model of a joint of the John S. Thompsonbridge is constructed. A critical location within the joint is identified. On this critical locations, several stress- and strain-based fatigue life analyses are performed, namely the use of Stress Concentration Factors (SCF), Smith-Watson-Topper’s (SWT) strain-life equation, and the multiaxial shear strain criterion (MSSC) method, to investigate the effects of incorporating mean stress effects and multiaxiality.
From these analyses, it is concluded that SCF appears to provide overly conservative fatigue life estimates, whereas SWT and MSSC provide more probable results. The increased life estimate through MSSC suggests a limited degree of multiaxiality present in the critical location. All three methods require a detailed FE model, complicating the fatigue assessment of the joint. While the SCF method is slightly simpler to use than SWT and MSSC, it does not weigh up to the conservativity of its life estimation. SWT is deemed the most suitable approach for the fatigue assessment of riveted joints, given that it is more widely applicable and relevant than MSSC.","Finite Element Analysis; Rivet; Local Approach; stress concentration factor; Fatigue Analysis; Bridge","en","master thesis","","","","","","","","","","","","Civil Engineering | Structural Engineering","",""
"uuid:690741fa-54b5-42c2-8555-2247ad55325d","http://resolver.tudelft.nl/uuid:690741fa-54b5-42c2-8555-2247ad55325d","Underwater 3D localization and communication for mobile networked robots","van Paassen, Daniel (TU Delft Electrical Engineering, Mathematics and Computer Science)","Venkatesha Prasad, Ranga Rao (mentor); Sharma, S. (mentor); Gaydadjiev, G. (graduation committee); Delft University of Technology (degree granting institution)","2024","","mobile robots; underwater 3D localization; anchor free lozalization; joint communication and sensing","en","master thesis","","","","","","","","2026-01-31","","","","Electrical Engineering | Embedded Systems","",""
"uuid:981d8332-7e6d-4dcc-8a60-027fc773c511","http://resolver.tudelft.nl/uuid:981d8332-7e6d-4dcc-8a60-027fc773c511","Hydrogen-based fuels for European aviation: A prospective life cycle assessment applying scenario analysis","Arblaster, Thomas (TU Delft Aerospace Engineering; TU Delft Technology, Policy and Management)","Steubing, Bernhard (mentor); Thonemann, Nils (mentor); Delft University of Technology (degree granting institution)","2024","Through exploratory scenario development, this study delves into the environmental impacts of European commercial aviation. Climate targets and the adoption of alternative aviation fuels (AAF) following ReFuelEU Aviation are assessed, considering e-fuel produced from direct air capture (DAC) and hydrogen aircraft. A novel method is applied, combining the generation of prospective life cycle inventories based on integrated assessment models with technology forecasting, system dynamics, and scenario development. This enables reflection on not only aircraft performance, but also fuel production, aircraft manufacturing, and fleet dynamics. Although there are limitations, including the relatively simple approach to system dynamics and limited data availability, clear conclusions can be drawn. Even for high-growth trajectories of air traffic, the total fuel demand of aviation could stagnate by 2035 under highly ambitious circumstances. Lower air traffic would require less ambitious circumstances. Combined with the reduced impact of AAF on aviation-induced cloudiness modelled here, the radiative forcing associated with aviation could reach a peak by 2050. However, the current scope of ReFuelEU Aviation does not prevent this peak from being eclipsed again by 2070. To prevent this, the mandate for a 70% share of AAF by 2050 should be followed up with a mandate for a 100% share. Thereby, warming neutrality is within reach – provided the necessary technologies can be implemented at scale. Hydrogen propulsion makes more efficient use of resources than e-fuel does, which is relevant for some impact categories, but less so for climate change as assessed here. When considering the magnitude of radiative forcing, present projections fall short. Estimating a budget of CO2 emissions through a grandfathering approach of the targets set by ICAO and IATA, the budget is exceeded by 2070, even with the most optimistic technological advancements. Critical here is the high use of fossil fuel leading up to 2035, for which there are no timely technological solutions. Lacking offsetting opportunities that are reliable, large-scale, and long-term, the only option is to restrict the volume of air traffic. Reducing traffic to 70% of the 2019 passenger-kilometers can be sufficient to respect the CO2 limit, even without optimistic developments in aircraft technology. This challenges conventional narratives, which advocate against demand management, claiming this would limit technological innovation. Thereby, evidence is created in support of the degrowth discourse which has gained momentum in recent decades. To ensure that aviation can provide long-term societal benefits, near-future flight activity must be redistributed to future generations. Given the boundaries and uncertainties of the presented scenarios, a much-needed discussion is encouraged: what share of global environmental limits is aviation – and within that, European aviation – entitled to?","Aviation; Life Cycle Assessment; LCA; ex-ante LCA; Scenario analysis; Climate change; Environmental impact; degrowth; Industrial ecology; Hydrogen","en","master thesis","","","","","","","","","","","","Industrial Ecology","",""
"uuid:17db8057-3bf4-469c-9986-a8ec6810171e","http://resolver.tudelft.nl/uuid:17db8057-3bf4-469c-9986-a8ec6810171e","Robustness Against Untargeted Attacks of Multi-Server Federated Learning for Image Classification: Are Defenses Based on Existing Methods Effective?","Mladenović, Todor (TU Delft Electrical Engineering, Mathematics and Computer Science)","Huang, J. (graduation committee); Chen, Lydia Y. (mentor); Delft University of Technology (degree granting institution)","2024","Multi-Server Federated Learning (MSFL) is a decentralised way to train a global model, taking a significant step toward enhanced privacy preservation while minimizing communication costs through the use of edge servers with overlapping reaches. In this context, the FedMes algorithm facilitates the aggregation of gradients, contributing to the convergence of the global model. Attacks that aim to reduce the accuracy of the global model are called untargeted attacks. One such attack that is particularly difficult to detect is the Min-Max attack. This paper explores the extension of existing defenses to enhance the robustness of MSFL against the Min-Max attack.
To do this, existing state-of-the-art defenses, including Median, Krum, Multi-Krum, Trimmed-Mean, Bulyan and DnC are extended and examined for their adaptability to this context. We refer to the extended versions of these defenses as FMes-Defenses.
Our results indicate that FMes-Defenses are ineffective in preventing the Min-Max attack from diminishing the accuracy of the global model. Surprisingly, we find even FMes-DnC is inadequate despite it's Single-Server counterpart (DnC) being renowned for mitigating the Min-Max attack.
These findings emphasise the need for novel defenses specifically tailored to the nuances of MSFL. While representing a significant stride in communication efficiency, MSFL, complemented by the FedMes algorithm, may require additional measures to ensure robust security against sophisticated untargeted attacks. This research contributes valuable insights into the challenges and importance of enhancing the security of MSFL in its ongoing development.","Multi-server FL; Untargeted Attack; DEFENSE","en","bachelor thesis","","","","","","","","","","","","Computer Science and Engineering","CSE3000 Research Project",""
"uuid:f2ad48f1-b960-4d36-a9fe-20486d3f0645","http://resolver.tudelft.nl/uuid:f2ad48f1-b960-4d36-a9fe-20486d3f0645","Adaptation of an MDO platform for system architecture optimization","García Sánchez, Raúl (TU Delft Aerospace Engineering)","la Rocca, G. (mentor); Bussemaker, J.H. (graduation committee); Garg, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","Early design decisions have a significant influence in the final success of the project. One of the most important decisions is to determine the system architecture, as it highly impacts the performance of the system. System architecture optimization can be used to determine the best possible architectures through the formulation of an optimization problem, allowing to explore the design space without traditional bias and conservatism.
MDO can be used to evaluate the performance of each architecture, allowing to consider the interactions between the multiple and coupled disciplines involved in the design process. To do this, MDO platforms have to satisfy multiple requirements, including the automatic readjustment of the MDO problem for each system architecture. They also have to be adapted to collaborative MDO, so that they can be used in real industrial cases.
Before this research, there was not MDO platform that satisfied all these requirements, impeding the integration of system architecture optimization in the industry. The MDO platform consisting on MDAx and RCE was adapted to collaborative MDO and satisfied all requirements to be used as architecture evaluator, except the automatic readjustment of the MDO problem. To fill the previous gap, the main objective of this research has been to extend MDAx backend code to allow the formulation of these
dynamic MDO problems, allowing to use it in the system architecture optimization process.
To achieve this, first the possible modifications that the system architectures can cause in the MDO problem, called architectural influences, are determined. Then, some possible implementation strategies MDO platforms can use to deal with these influences are presented. After that, the actual implementation process used to extend MDAx backend code is widely discussed.
Afterwards, a benchmark problem based on Fourier series is used to verify the implementation. A real engineering problem, based on the design of a space multistage rocket, is also used as validation to show the potential tool, and more generally, of the methodology. Finally, some conclusions and possible future steps are drawn.
In conclusion, this research allows to reduce the existing gap between system architecture optimization and MDO by obtaining an MDO platform that can be used as an architecture evaluator. Also, the different requirements identified for the inclusion of architectural influences, as well as the benchmark problems discussed, are aimed to help developers to extend their MDO platforms to be adapted to system architecture optimization, reducing the barriers for its implementation in the industry.
The industry needs a guide for safely designing, developing, and deploying AI systems, considering stakeholders' perspectives. This guide fills two knowledge gaps: a framework for translating high-level values into Japanese life insurance industry requirements and an initial process for converting these high-level values into organizational guidelines.
An empirical study on predictive underwriting informed the research, identifying 13 values and four informal social institutions for the AI design process. It involved eight experts who defined 54 norms, which were later refined and categorized into process and assessment norms focusing on data and AI.
The result is ten design guidelines for AI system developers, which are validated by experts, addressing the full AI lifecycle. These guidelines contribute scientifically by introducing an initial process combining design for values with system safety concepts, reporting standardization, and AI governance frameworks.
Future research should replicate this process in various contexts, reevaluate the value framework with broader stakeholder inputs, investigate the dynamics between Japanese society and AI in more detail, and delve deeper into system theoretic hazards analysis. This approach promises to strengthen the value framework and process applicability in different organizational settings.
The first scenario is represented by damages located in the CFRP structural part of the fuselage access panel. The scarf repair method was identified as the optimal one for this instance, research effort was therefore directed towards its improvement. Indeed, such technique does not currently allow to achieve a fully flush surface, as a mismatch between the repaired area and the undamaged one remains noticeable. Eliminating such unevenness is crucial for stealth and eventually aerodynamic reasons, and therefore needs to be investigated. Two repair configurations were implemented: the first one consists of re-milling the surface once the repair is completed, while the second one relies on a thinner repair patch that — once properly aligned — allows for a flush surface. The first option allowed for an improvement of over 80\%, reducing the surface unevenness from more than 1/2 of a millimeter to less than a 1/10, while ensuring a smooth, continuous surface finish. At the same time, it proved capable of meeting all the mechanical requirements, performing closely to a reference repair configuration in several tests. On the other hand, the second option only partially improved the surface finish, but fell short of the fatigue life requirement by a large margin and also showed a significantly poorer mechanical performance compared to the reference repair and the other configuration.
The second scenario is represented by small, cosmetic damages located in the functional edge of the fuselage access panel. It was identified that such damages are best addressed with repair procedures based on a filler compound. Guidelines to define such repair compounds were defined. Then, two repair procedures based on the use of these compounds were thought out: the first one is similar to conventional filling repair processes, while the second one relies on a bespoke tool to inject the repair compound. The former was implemented and produced promising results: it allowed to precisely restore the original profile and achieve a seamless surface finish. Damages affecting both the structural and functional parts were also briefly addressed, paving the way for future developments.","","en","master thesis","","","","","","","","2026-01-26","","","","Aerospace Engineering | Structures and Materials","",""
"uuid:89958aaf-a224-43c4-a5c6-0e4335c92f3d","http://resolver.tudelft.nl/uuid:89958aaf-a224-43c4-a5c6-0e4335c92f3d","Resilience policy. What it means, how do we build it, what tools can we use to understand it","Ashkenazy, A. (TU Delft Energie and Industrie)","Herder, P.M. (promotor); Nikolic, I. (copromotor); Delft University of Technology (degree granting institution)","2024","Governments all over the world have been searching for ways to build resilience to a myriad of risks, which seem to intensify in frequency and potential impact – from the Covid-19 pandemic to climate change, from AI running loose to economic crises that defy our expectations and understanding. Many have embraced concepts and ideas from resilience thinking, and applied them to particular shocks and stressors, or even as a holistic framework for city resilience in face of multiple shocks and stressors. Thus, a new policy domain emerged – resilience policy. However, unlike other policy domains, such as environmental policy or health policy, it lacks a clear definition of goals, methods of analysis, and trade-offs. This is the gap this dissertation
starts to bridge.","","en","doctoral thesis","","978-94-93330-57-3","","","","","","","","","Energie and Industrie","","",""
"uuid:ab25d2b8-36dd-4312-b444-96cbaba5cce1","http://resolver.tudelft.nl/uuid:ab25d2b8-36dd-4312-b444-96cbaba5cce1","Installation of perforated monopiles: And the associated fatigue damage","Twigt, Tom","Vergassola, M. (mentor); Colomés, Oriol (mentor); Delft University of Technology (degree granting institution)","2024","The European offshore wind industry has experienced significant growth in the past decade, mainly focusing on shallow areas in the North Sea to reduce the Levelised Cost of Electricity (LCoE) and compete with fossil fuels. However, as shallow areas become scarcer and the industry seeks greater independence from government subsidies, a shift towards deeper waters is anticipated, and already observed in Europe. In the northern part of the North Sea (60-120 meters deep), jacket foundations are currently favoured, despite drawbacks such as extensive engineering efforts, weld requirements, challenging series production, and high costs. This misalignment with the industry's LCoE reduction goal highlights the need for a technologically viable and economically attractive foundation concept for waters in the 60-120-meter range.
To combat this challenge, perforated monopiles are being developed. The perforated monopile consists of a monopile with perforations, either circular or elliptical, around the splash zone, with the goal of reducing the frontal area, and thus reducing the hydrodynamic loads on the structure. These concepts aim to combine the ease of manufacturing of a monopile, with the reduced area affected by hydrodynamic loads that are common for jacket structures. The research done so far on these perforated monopiles has only looked at the reduction in hydrodynamic loads, which have proven significant. These reductions in hydrodynamic loads should enable the perforated monopiles to be used in deeper waters compared to regular, non-perforated, monopiles. They could provide a tempting alternative for the more expensive jacket structures, but more research is necessary, especially in analyzing other loads that the perforated monopile may be subject to.
This thesis aims to look at one such different load that affects this perforated monopile, namely the installation loads induced by hammering. The first part of this thesis will look at stresses and fatigue damage during the installation of non-perforated monopiles. The second part will analyze the increased stresses, possible losses in hammer energy, and increased fatigue damage, all due to the presence of perforations. Finally, several alternatives, such as different geometries of perforations and different hammer loads will be analyzed with regard to their effect on fatigue damage.
The fatigue damage due to installation is found to increase significantly due to the presence of perforations, increasing from 5% for non-perforated monopiles, to up to 118% and 112% for the two most promising geometries analyzed, thus proving a show-stopper for installation via impact hammer, if no measures are taken.
Changing certain parameters, however, either the geometries of the perforations, or the characteristics of the hammer used, shows that installation is indeed possible. Using different geometries of perforations, that maintain a significant reduction in area, shows installation is possible, whilst limiting the fatigue damage to 53%. A reduction in hammer force by a factor of 2, also decreases the fatigue damage by 34% on average. The use of a so-called vibro-hammer also shows promising, resulting in a halving of the fatigue damage compared to the use of an impact hammer, but more research needs to be done to confirm this final finding.
To conclude, this research shows that installation of a perforated monopile is possible, although most, if not all of the reduction in fatigue damage due to hydrodynamic loading is cancelled out by the increase in fatigue damage due to installation. Geometries and installation methods may exist that improve the fatigue life of the structure, but this research was unable to find them. Future research may be able to find geometries and installation loads that do reduce overall fatigue damage.
Further research is also necessary before perforated monopiles can be taken into service, such as the confirmation of the energy losses in installation due to perforations. Also, several other load cases need to be analyzed, to ensure the perforated monopile survives its designed lifetime.","Fatigue Analysis; pile driving; monopile; perforated monopiles","en","master thesis","","","","","","","","","","","","Offshore and Dredging Engineering","",""
"uuid:4e40b7d4-975e-4b88-b87b-f247fadc343a","http://resolver.tudelft.nl/uuid:4e40b7d4-975e-4b88-b87b-f247fadc343a","High-strength steel: ultimate material or expensive alternative?: Feasibility and optimization of using high-strength structural steel in offshore topsides","Dekkers, Wout (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Offshore and Dredging Engineering)","Hoving, J.S. (mentor); van der Stap, A.C.M. (graduation committee); Tankova, T. (graduation committee); Delft University of Technology (degree granting institution)","2024","Steel is a widely used material in construction because of its availability, high strength-to-weight ratio, and recyclability. However, steel manufacturing consumes a lot of energy, and there is an increasing demand for more environmentally friendly building materials. Consequently, high-strength steel is becoming more popular as it reduces the mass of a structure. Although high-strength steel has been available for many years, its use in offshore topsides is limited due to stability and deflection issues. This research aimed to assess the feasibility of utilizing high-strength structural steel in offshore topsides, and investigated how the use of high-strength steel can be optimized in topside design.
Two different screening tools were constructed to assess the feasibility of high-strength steel within an entire topside. It was concluded that the length of a particular beam can tell an engineer if it is worth further investigating the potential of high-strength steel, while columns showed potential in all cases. The methods were tested with a case study in which an topside was assessed for its feasibility of utilizing high-strength steel beams and columns. Only hot-rolled primary and secondary beams combined with the columns and bracings were considered for this topside. When S460M steel was used for strength-governing beams and seamless tubulars, in combination with S690Q steel for welded tubular columns, the highest benefits were found and a maximum steel weight reduction of 15% was found for the considered components. At the same time, the material costs were reduced by 10%, the welding costs by 13% and the embodied carbon savings equalled 14%. When comparing these results with the total topside steel weight, 5% of the topside steel weight was reduced by using a combination of S460 and S690 steels. It was concluded that high-strength steel is feasible for offshore topsides and is more environmentally friendly and cost-effective, providing a promising alternative to conventional steels within certain components on offshore topsides.
This research presented a screening tool that is simple to use and assessed the feasibility of high-strength steel. Other engineers can easily extend this tool. As more detailed calculations are included in the screening tool, it is expected that additional cost reductions and embodied carbon savings can be found. Furthermore, including additional steel components in the assessment, such as plate girders, may result in finding much higher total weight reductions.
Damage dealt to the central nervous system (CNS) caused by trauma or disease can have detrimental effects on human quality of life because the CNS has limited regenerative capabilities. Efforts to replace lost neural cells require improved knowledge and methods for differentiation of neural stem cells (NSCs).
Objective
In this thesis, I aim to chart our current scientific knowledge and progression of neural differentiation and explore practically the feasibility of continuous ultrasound (US) stimulation on neural progenitor cells (NPCs) differentiating into neurons in vitro.
Methods
I performed a literature study examining previous studies that investigated electrical stimulation, nanoparticles, or ultrasound to improve in vitro or in vivo differentiation of neural stem cells. Using finite element method (FEM) frequency analyses with COMSOL Multiphysics, I investigated the use of a 24-wells plate with piezoelectric lead zirconate titanate [Pb(ZrxTi1–x)O3] (PZT) US transducers. Additionally, I validated in vitro previous findings on the feasibility of differentiation of NSCs to NPCs.
Results
With the knowledge gained from literature and findings from the experiments, I created a mold for the fabrication of a custom variant of a 24-wells plate made with polydimethylsiloxane (PDMS) to which 2.03 mm thick PZT can be mounted.
Conclusion
Future research efforts should focus on further developing this technique, specifically into electrical schemes to optimize US transmission to NPCs.","","en","master thesis","","","","","","","","","","","","Biomedical Engineering","",""
"uuid:ea764848-033f-45f7-a159-51b34fb09620","http://resolver.tudelft.nl/uuid:ea764848-033f-45f7-a159-51b34fb09620","Quantitative Analysis of Flame Kinematics in Premixed Hydrogen-Air-DNG Jet Flames using PIV Measurements and Flame Front Segmentation","Gunce, Cem (TU Delft Mechanical, Maritime and Materials Engineering)","Klein, S.A. (mentor); Tummers, M.J. (mentor); Delft University of Technology (degree granting institution)","2024","Today's electricity supply falls short of current demands, leading to the utilization of gas turbines in both ground based and avionic infrastructures. Nevertheless, these often rely on carbon-based fuels, resulting in escalating CO2 emissions. However, adopting hydrogen as a fuel eliminates carbon emissions. Aside from zero carbon emissions, hydrogen has a higher energy density by weight compared to conventional fuels. This makes it an distinct option for applications requiring efficient energy storage and delivery. Due to its wide flammability range and low ignition energy, hydrogen can combust in scenarios where traditional fuels might not. This unique characteristic, while advantageous in certain contexts, requires detailed study to ensure safe and efficient combustion in gas turbines. However, the combustion of hydrogen inherently results in elevated flame temperatures, thereby generating increased NOx levels. Furthermore, hydrogen's high mass diffusivity translates to a reduced Lewis number. Consequently, it becomes vital to grasp the local dynamic characteristics of the flames, particularly at stable and flashback points. Understanding the thermo-physical behavior of hydrogen flames, especially at stable and flashback points, therefore, requires experimental studies to reflect real life complexities. These tools can offer insights into turbulence-flame interactions, flame stabilization, and emission formation mechanisms.
In this research, an exploration was undertaken to understand the local kinematics and dynamics of Hydrogen and DNG flames, with emphasis on stable states and those approaching flashback conditions. Particle Image Velocimetry (PIV) experiments were employed on a Bunsen burner setup, facilitating the capture of the jet flames' velocity fields. Both low-speed and high-speed recordings were captured by high-speed camera, providing distinct insights into flame dynamics. Flame front detection was achieved using Mie-scattering, capitalizing on the differential seeding particle densities between the unburnt and burnt regions. Intensity differences between these regions were meticulously captured with a bilateral filter, leading to the successful extraction of the flame front. This extracted front was subsequently distinguished via segmentation and superimposed onto the velocity field. Low-speed recordings offered a generalized perspective on flame turbulence characteristics through cold flow validation, while high-speed recordings unveiled specific dynamics, inclusive of flame curvature, local flame and displacement speeds, and both normal and tangential velocities and stretches. It consistently holds the 1-D unstretched flame speed, even as the Reynolds number increases, aligning with the respective flashback points and stable conditions of the flames. As a result, in-depth comparison of DNG and $H_2$ fuels in terms of flame dynamics and kinematics were discerned.","Hydrogen Combustion; PIV (particle image velocimetry); image segmentation; Data analysis; Flame front edge detection algorithms","en","master thesis","","","","","","","","2024-01-26","","","","Mechanical Engineering | Energy, Flow and Process Technology","",""
"uuid:d402bc20-8884-4051-b78c-9ccc84e34eeb","http://resolver.tudelft.nl/uuid:d402bc20-8884-4051-b78c-9ccc84e34eeb","Aerodynamics of cylinders in tandem: Experimental investigation by stereoscopic PIV","Bajuk, Jože (TU Delft Aerospace Engineering)","Sciacchitano, A. (mentor); Ubbens, H. (mentor); Terra, W. (mentor); Delft University of Technology (degree granting institution)","2024","This thesis investigates the aerodynamics of two finite wall-mounted cylinders in tandem, focusing on drag reduction as a function of governing parameters.
For the experimental wind tunnel campaign, two measurement techniques were employed: balance measurements and stereoscopic particle image velocimetry. While balance measurements exhibited good repeatability, drag values obtained with PIV saw high uncertainty and only limited conclusions could be made from it.
Cylinders were mounted to the floor of a closed wind tunnel test section. The trailing cylinder was rigidly attached to the balance underneath, while the leading cylinder could move upstream to the de- sired distance. Stereoscopic PIV images of the wake at various distances upstream and downstream were taken through the transparent sides of the wind tunnel. These images, in combination with the control volume approach, were used to determine the drag of a trailing cylinder.
Coefficients of drag, obtained with a balance for isolated cylinders of various aspect ratios, were in line with similar results from the literature, albeit on the higher side. For cylinders in tandem of the same aspect ratio, AR, as the distance between them increased, the CD of a trailing cylinder converged to that of an isolated cylinder. Comparing tandem configurations with different AR and at the same nondi- mensionalized in-between distance, trailing cylinders with larger AR experienced larger drag reduction.
Introducing cylinder diameter ratio as an additional degree of freedom showed that smaller diameter trailing cylinders experienced greater drag reduction at close distances. However, at a certain distance further downstream, this trend reversed.
The drag reduction values obtained with PIV confirmed the findings from balance measurements. How- ever, due to the limited set of usable data, further work would need to be carried out to gain more confidence in the method.","Cylinder aerodynamics; Cylinders in tandem; Stereoscopic PIV; Drag reduction; Bluff body aerodynamics; PIV (particle image velocimetry); Drafting","en","master thesis","","","","","","","","","","","","Aerospace Engineering | Aerodynamics","",""
"uuid:446e9903-7d61-4de1-9d54-ef6788713b67","http://resolver.tudelft.nl/uuid:446e9903-7d61-4de1-9d54-ef6788713b67","Optimizing Revision Total Knee Arthroplasty: An In-Depth Analysis of 3D Planning Prediction and Patient-Specific Instruments for Revision Surgery","van der Laan, Thom (TU Delft Mechanical, Maritime and Materials Engineering)","Harlaar, J. (graduation committee); van Oldenrijk, J (mentor); Cornelissen, Bart (graduation committee); Veltman, E (graduation committee); Delft University of Technology (degree granting institution)","2024","In today’s medicine, 3D planning and PSI are not commonly used in revision TKA surgery and little is known about the accuracy and implementation of these techniques in revision TKA. Therefore, the question arises, what are the potential benefits of 3D planning and PSI in revision surgery? The goal of this thesis is to explore the potential benefits of 3D planning and PSI in revision surgery. To achieve this, a retrospective study and a prospective study are performed, and a first design of a 3D printed PSI is created. For both retrospective and prospective study, 3D plannings are made of patients undergoing revision TKA, comparing the pre-operative planning with the post-operative results based on size prediction, augmentation prediction and component placement analysis. The results of the studies conducted in this research align closely with each other, providing similar results for size and augmentation prediction and component placement analysis. All in all, these studies indicated consistency and reliability of the 3D prediction in different scenarios, affirming the potential of 3D planning in revision TKA surgery. Additionally, the first design for a PSI, a 3D-printed guide, is constructed. This design incorporates several important landmarks for component placement during revision TKA, increasing the outcome of these surgeries, especially if landmarks are missing or unidentifiable during surgery. Together 3D planning and PSI have a bright future in revision surgery, however, future research needs to be conducted to implement 3D planning and PSI in modern-day healthcare.","TKA; revision; 3D planning; PSI","en","master thesis","","","","","","","","","","","","Technical Medicine","TM30004; 35 ECTS",""
"uuid:0150a022-d7e6-46d9-8c8f-3c50d5962637","http://resolver.tudelft.nl/uuid:0150a022-d7e6-46d9-8c8f-3c50d5962637","The fast track to flexibility in public procurement: An exploratory study on institutional design concepts for the Dutch Railways using a morphological chart","Schenk, Nena (TU Delft Technology, Policy and Management)","Renes, Sander (mentor); Veeneman, Wijnand (mentor); Smulders, T. (graduation committee); Michielsen, A.L.P.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Fast developing technology offers many opportunities for innovation and optimization in the public domain. However this sector is bound to European directives on public procurement transposed into national law and therefore bound to the mandatory procurement of, among others, their assets. This legislation provides a limiting framework in which, after awarding the contract, little room for design adjustments is perceived to be left. As a result assets, especially with long-term procurement processes, are not in accordance with current technological development. The limited amount of literature on this subject provides mitigation in very specific cases, but no overview of flexibilities in the procurement process exists, which is therefore the objective of this research. The Dutch railway sector was used as context of this research and since most process design choices are made by the procurer, the Nederlandse Spoorwegen (NS) [Dutch Railways].
First, the current process was mapped out using the functional modelling technique IDEF0 based on which a first identification of flexibilities was performed. Subsequently, a first version of a morphological chart (MC) was made. This is a product design tool, in this research used, tested and validated for institutional design, as a parallel research focus supporting the exploration of flexibilities. The MC was developed and validated on its content as well as its use as institutional design tool. Additionally, validated trends were identified in the combination of flexibility aspects, followed by the exploration of a future institutional design for the NS.
During this research four additional construction rules for the MC were found, being (1) within scope of action, (2) readability, (3) abstraction level and (4) informational value, for which a variety of practical solutions are suggested. These were adhered to in the developed MC and resulted in the validation of this tool to be useful as systematic, substantiated and concrete guidance in the discussion of process design.
Using these developed conditions for the MC enabled identification and representation of aspects enhancing flexibility, being split into three chapters being Product, Contract and Market Approach. Validated conceptual designs enhancing flexibility were created by combining different fragments of solutions into one conceptual design. Six of these were created, one being the “traditional” procurement, four were based on collaborative practices and the last was based on the product to be part of a network. These four conceptual designs based on collaboration focused on: a partnership for the separate development of innovation, international collaboration and supplier-procurer collaboration of a light and more extensive degree.
Applying this to the case of the NS shows that separate innovation and extensive collaboration are perceived to be most suitable as starting point of their future procurement design.
Altogether it can be concluded that commencing a shift from a vertical to a horizontal approach within the buyer-supplier interaction is essential, placing greater importance on formalizing the partnership rather than specifying precise outcomes. The required redesign for enhanced flexibility to intermediate design changes in public procurement processes can be obtained by using the developed MC as guidance for discussion on the process design...
During an explosion, the energy released from the blast will be absorbed by the composite material. This often results in the delamination of plies within the laminate. Due to the delamination, bending loads will be taken over by membrane loads. This is proven advantageous for composite materials as they are stronger in membrane loading.
Unfortunately, modelling sizeable composite structures with a Direct Numerical Simulation (DNS) requires the use of a lot of elements. This, in turn, results in long computational times, particularly for non-linear analyses. Multiscale modelling is a possible solution to this problem.
This study explores the method of Computational Homogenisation for delamination in composite laminates as an alternative to 3D DNS modelling. Two-dimensional Shell-Interface-Shell elements (SIFS elements) are introduced on the macroscale. These double-layered shell elements consist of two stacked Mindlin-Reissner shell elements with an interface element connecting the two shells. Each integration point of a SIFS element is linked to a mesoscopic 3D coupled Representative Volume Element (cRVE), which is also split into two shells with an interface in between. By applying linear and periodic boundary conditions that incorporate the macroscopic strains on the cRVE, mesoscopic stresses are determined, leading to macroscopic stresses and the macroscopic stiffness matrix.
The proposed multiscale framework is validated by a set of load cases with different ply configurations. The results are then compared to those of a 3D DNS. The multiscale framework performs reasonably well; however, it is not without its limitations. Firstly, the cRVE exhibits width dependence, requiring the implementation of a sufficiently narrow cRVE for accurate results. Additionally, SIFS elements may lack kinematic consistency with 3D solid elements, constraining certain deformations and resulting in overly stiff responses for SIFS analyses. The proposed multiscale framework might not perform as accurately as the 3D DNS in specific load cases, one of which is explored in this work.
Returning to the original goal of this work for the multiscale model, certain extensions still need to be implemented to design composite laminates for blast protection. Implementation of the arc-length method will provide insight into snapback behaviour that could occur during loading. Next, the macroscale and mesoscale models need to be adapted for multiple delaminations over the height of a laminate. Furthermore, the implementation of dynamic loading is a necessary step, as blast loads induce strong dynamic behaviour. Finally, the integration of Artificial Intelligence / Machine Learning into the framework could improve the model by further reducing computational time.","Computational Mechanics; Computational Homogenisation; Multiscale Framework; Composite Laminates; Delamination","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:cc9f60a7-9926-4954-8427-be2437c4e355","http://resolver.tudelft.nl/uuid:cc9f60a7-9926-4954-8427-be2437c4e355","Finding Companions in the YSES IFS Data","Burr, Zach (TU Delft Aerospace Engineering)","Kenworthy, M.A. (mentor); Delft University of Technology (degree granting institution)","2024","Planet formation is a topic that still has many unanswered questions, particularly regarding the formation of wide orbit giant planets. Detecting more of these types of planets can aid understanding of how they form by giving examples of what kind of planets exist. Direct imaging is uniquely well suited to detecting these kinds of planets, which is why several direct imaging surveys have been launched with this goal. Including the Young Suns Exoplanet Survey, which is looking specifically for wide orbit giant planets around young solar analogues.
The survey makes use of the IRDIS instrument on the VLT, which images in parallel with the IFS. By analyzing the IRDIS data, the researchers have already detected three planets in two systems. However, the IFS data has not yet been analyzed. That was the goal for this thesis: to contribute to YSES and the broader scientific community by analyzing the IFS data to search for potential companions.
In total, 41 observations of 37 different star systems were analyzed. The data was pre- and post-processed (with SDI), and candidate companions were identified and examined. Eight candidate companions were found in five systems. Of those candidates, all were determined to be background stars and not related to the host. Two were bright single stars. One system had two M-dwarf candidate companions that were in a binary system together. The last two systems each had two candidate companions, and in both cases it was revealed that these candidates form a triple system of their own, with one of the candidates being an unresolved binary. One of these triple systems was previously thought to be an equal mass binary with the host star, however this thesis has proved that this is not the case.
All of the systems analyzed also had detection limits computed. This gives a good idea for what size of objects could have been seen if they had been in the images. For most systems, the limit after SDI is around 5-10 Jupiter masses at 0.3""-0.5"". This leaves room for planetary mass companions in these systems which could be found in follow-up observations. The two background triple systems should also have follow-up observations performed, as this configuration is somewhat unusual and warrants further study.","exoplanets; high contrast imaging; image processing; differential imaging; direct imaging; giant planets","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:a144a873-d51b-4b52-8abb-0c07868f5f92","http://resolver.tudelft.nl/uuid:a144a873-d51b-4b52-8abb-0c07868f5f92","Dynamic Target Time Management with Reinforcement Learning: A case study on Zurich short-haul regulated arrivals","Caranti, Leonardo (TU Delft Aerospace Engineering)","Ribeiro, M.J. (mentor); Carré, Marie (graduation committee); Santos, Bruno F. (graduation committee); Delft University of Technology (degree granting institution)","2024","This Master Thesis investigates the possible improvements to the Target Time Management concept to optimize the arrival flows for SWISS International Airlines. The aim is to improve operational performance based on the current model used, as well as prove that Target Time Management constitutes a valuable system to improve operations in a dynamic way. To leverage the dynamic nature of slot assignment, an environment model is created and used as training base for two Multi-Agent Reinforcement Learning algorithms. These two algorithms, Soft-Actor Critic (SAC) and Proximal Policy Optimization (PPO), are then tested against the baseline model currently used in operations at SWISS (based on Mixed-Integer Linear Programming). The four domains to measure the algorithms' performance are passenger connecting time, curfew performance, rotation delay and fairness to other airlines. The algorithms were trained in a simulation environment based on statistical representations of the dynamics of the slot allocation system of EUROCONTROL. They were then tested with new data, where they outperformed a MILP implementation in passenger connecting time and rotation delay metrics (curfew and fairness were comparable in magnitude, since the MILP was slightly unfair for SWISS and RL was slightly unfair for other airlines). PPO was then also tested on the real slot assignment environment hosted by EUROCONTROL and once again compared to a MILP approach. Here, it was found that the improvement in critical passenger connecting time was 5.0 minutes for the MILP, and 5.9 minutes for PPO. Rotation delay was improved by 0.9 minutes by the MILP, and by 4.8 minutes by PPO. PPO also made the highest delays higher and the lowest delays lower, which would require EUROCONTROL or SkyGuide representatives to interpret and make conclusions on fairness and safety. Curfew performance was optimal for both methods. In conclusion, it is proven that Reinforcement Learning techniques can aid the dynamicity of decision-making within Target Time Management. It is also proven that Target Time Management with a dynamic decision making approach can improve operational performance compared to a static one.","Air Traffic Management; Airlines Operations; Target Time Management; Machine Learning; Reinforcement Learning; Soft-Actor Critic; Proximal Policy Optimization; Mixed-Integer Linear Programming","en","master thesis","","","","","","","","2026-01-26","","","","Aerospace Engineering","","47.462075, 8.549797"
"uuid:39aa5049-4826-464d-8500-f20248e0fdee","http://resolver.tudelft.nl/uuid:39aa5049-4826-464d-8500-f20248e0fdee","Impact of Ice Sheet-Climate Interactions on Greenland Ice Sheet Mass Balance: Insights from Coupled CESM2-CISM2 Simulations","Feenstra, Thirza (TU Delft Civil Engineering & Geosciences; TU Delft Geoscience and Remote Sensing)","Vizcaino, M. (mentor); Wouters, B. (graduation committee); Steele-Dunne, S.C. (graduation committee); Delft University of Technology (degree granting institution)","2024","The Greenland Ice Sheet (GrIS), which stores freshwater equal to more than seven meters of potential sea level rise, strongly interacts with the global, Arctic and North Atlantic climate. In a warming climate, the GrIS has been losing mass and is projected to lose mass at an increasing rate. The interactions between the GrIS and the climate have the potential to amplify or dampen GrIS mass balance responses to a CO2 forcing. We investigate the impact of ice sheet-climate interactions on the mass balance and climate of the GrIS using the Community Ice Sheet Model version 2 (CISM2) coupled to the Community Earth System Model version 2 (CESM2). We compare idealized simulations with a non-evolving and evolving ice sheet topography in which we apply an annual 1 % increase until we reach four times pre-industrial (PI) CO2 concentrations. Furthermore, we analyze an idealized simulation in which we first apply a 4x PI CO2 forcing and thereafter annually reduce atmospheric CO2 by 5 % until PI concentrations are reached. By comparison of a 1- and 2-way coupled simulation, we find significant changes in atmospheric blocking, precipitation and cloud formation over Greenland as the GrIS topography evolves, acting as negative feedback mechanisms on mass loss. Besides, we find that a uniform temperature lapse rate misrepresents temperature changes in the ablation area, leading to an overestimation of the positive melt-elevation and melt-albedo feedback in 1-way coupled simulations, resulting in an overestimation of mass loss. During a 350 year 4xPI CO2 forcing period, the ice sheet loses a total mass of 1.1 m sea level equivalent, and part of its margins retreat land inward. When applying an annual 5 % decrease in CO2 to 1xPI CO2 concentrations, melt reduces rapidly. The small discharge concerned with the retreated state of the ice sheet allows for halting the GrIS mass loss, despite a surface mass balance that is only slightly positive under a remaining global warming of 2 K. During a complex transitional phase towards a colder climate, the GrIS, Arctic and North Atlantic ocean strongly interact, causing the area south of the GrIS to transition from a ’warming hole’ towards a ’cooling hole’. Elevated atmospheric temperatures, larger ocean heat transport and a poorer state of the snowpack, compared to the initial pre-industrial state, result in limited regrowth of the ice sheet under reintroduced PI CO2 conditions.","Earth system modelling; Ice sheet modelling; Ice sheet-climate interactions; Greenland Ice Sheet; Climate change; Sea level rise","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:10645ab7-581f-4b38-88aa-5b3c767fb2c9","http://resolver.tudelft.nl/uuid:10645ab7-581f-4b38-88aa-5b3c767fb2c9","Health data sharing for clinical research : Designing a patient-centric approach","Ghasia, Zahra (TU Delft Industrial Design Engineering)","van Heur, R.J.H.G. (mentor); Bourgeois, Jacky (graduation committee); Salami, Nima (graduation committee); Delft University of Technology (degree granting institution)","2024","The use of Electronic Health Records (EHRs) has seen a breakthrough in clinical research for personalized treatments (Hamburg & Collins, 2010.) Despite the potential advantages of vast EHR data available, constraints of privacy and legislation hinder its use (Rieke et al., 2020.) Health data exists in an interconnected healthcare system (Harris et al., 2009), comprising of stakeholders responsible for health data management within the constraints of GDPR. Data sharing platforms, through the use of secure data sharing practices and encrypted technology, can potentially change the landscape of health data in clinical research (Obermeyer & Emanuel, 2016.)
This project examines the privacy and stakeholder landscape of health data sharing through an evaluation of interaction with patients. It uses a Value-Sensitive design approach (Friedman et al., 2002) to contextualize the privacy values in clinical research for patients, doctors, patient organizations, clinical researchers, pharmaceutical industries and data sharing platforms. Through this examination, it identifies lack of transparent data use and research practices as a hindrance to the use of health data on a data sharing platform. Transparency is examined through a patient-centric lens, wherein information and control over preferences of participation are found to be crucial. This evaluation further identifies roles of researchers and data sharing platforms for a transparent approach.
The project results in a concept termed ‘Negotiated Consent‘, which examines the use of data sharing platforms in offering individuals transparency. This is contextualized within patient consent for recruitment in clinical research, wherein data sharing platforms are responsible for data processing through the use of Federated Learning and Natural Language Processing. The stakeholder landscape for the same is defined in 3 functions for the platform- Access to Health Data, Patient Consent and Recruitment, and Data-Driven Insights. The results are tested through a study of the prototyped user experience of ‘Negotiated Consent‘, wherein participants emphasized ‘feeling more informed and in control’ in comparison to the current informed consent.
Whilst the study examines a patient-centric approach towards health data sharing for clinical research, it has limitations in addressing the multi-faceted reality of patient’s lives that informs their choices to enrol in clinical research. The further development of patient-centricity in the domain requires examination of motivations through a lens of disease-specific patient groups, demographics, and personal history with diseases (Hong et al., 2020) will lead to richer insights. Furthermore, Negotiated Consent is a proof-of-concept for dynamic consent (Mascalzoni et al., 2022), that demonstrates revision over participation choices within one moment of patient consent.
This project contributes to an understanding of the privacy and stakeholder dynamics for health data sharing. It illuminates a transparent approach to recruitment for clinical research through a collaborative effort that emphasizes on patient-centric approaches. Using a mutually responsible approach, data sharing platforms can lead the way for use of data in clinical research that simultaneously empowers patients to control their data through a negotiated lens.","Health Data; Privacy; Informed Consent; Data sharing; Machine Learning; Ethics of Technology; Health Tech; GDPR; Data donation; Value-Sensitive Design; Systemic Design; Design for healthcare","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:3ca9c554-1473-48a2-813b-52dd0c2753d9","http://resolver.tudelft.nl/uuid:3ca9c554-1473-48a2-813b-52dd0c2753d9","Neurosymbolic AI for Complex Event Detection with Expert Knowledge","van Wijk, Willemijn (TU Delft Mechanical, Maritime and Materials Engineering)","Hellendoorn, J. (mentor); Hernández, Carlos (graduation committee); Boldrer, M. (graduation committee); Aljawaheri, D. (mentor); Delft University of Technology (degree granting institution)","2024","","","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:37b9c0d9-f07a-40a9-b93e-ea41ab5f02e2","http://resolver.tudelft.nl/uuid:37b9c0d9-f07a-40a9-b93e-ea41ab5f02e2","Looking for the soft spot in “The Iron Triangle”: Explorative research into the effect of serious gaming on the level of empathy and the experienced client contractor collaboration of professionals in the construction industry","Ambagts, Janneke (TU Delft Civil Engineering & Geosciences)","Bekebrede, G. (mentor); Houwing, E.J. (mentor); Koolwijk, J.S.J. (graduation committee); Van den Berg, Nick (mentor); Delft University of Technology (degree granting institution)","2024","This master thesis addresses the challenge of project performance in the Civil Engineering (CE) sector, emphasizing the significance of collaboration, communication, and understanding among interdisciplinary project teams. Focusing on the role of empathy in contractor-client collaborations, the study investigates the potential impact of serious gaming on enhancing the level of empathy of CE professionals.
The research uses a mixed-method pre- and post-test design, utilizing a quasi-experimental approach without a control group. The study uses the Interpersonal Reactivity Index (IRI) and the short version of the Empathy Quotient (EQ short) questionnaire to measure the individual self-reported level of empathy before and after participants engage in the serious game 'Fouten maken Moed.' A subscale of the IRI showed a slight decrease in the level of empathy that possibly can be explained by a growth in awareness. While quantitative analysis did not reveal a significant change in overall empathy scores, qualitative findings suggest positive influences on interpersonal dynamics, openness, and talkativeness among participants, aspects that relate to the concept of empathy.
Despite the limitations that arise from researching a difficult to operationalise main concept (empathy), a small sample size and having no control group. It can still be concluded that the intervention, including the serious game, created an environment that was conducive for participants to share personal information and vulnerabilities, fostering a sense of approachability and relatability. It seems like the game can, if facilitated well, function as a context-setter for Project Follow Up (PFU) or Project Start Up (PSU) meetings, enhancing collaboration between contractors and clients.
Although the study acknowledges the fact that results cannot be generalised, it recommends refining empathy measurement methods and enhancing training interventions' briefing and debriefing aspects. Future research should include more extensive experiments with control groups to better isolate the impact of serious gaming on empathy levels in the CE sector, providing a more comprehensive understanding of the game's potential contributions to collaboration and project performance through empathy
Goal
The development and validation of an improved GelMA disturbed flow model for in vitro validation of cell culturing under disturbed flow conditions.
Method
To determine the compressive modulus of the GelMA, three sets of samples are produced with different exposure times to UV light. These samples were subjected to compressive testing to determine the pressure/strain characteristics of the GelMA.
Furthermore, the disturbed flow model is partially newly designed. A new cover allows for incorporating a pressure sensor to determine if the model can operate under physiological pressure levels. To achieve this pressure, a pump with adjustable flow output is selected. Flowmeters were included in the test setup to determine when the correct flow was performed. The balance between the right pressure and flow results is described as the systemic vascular resistance of the disturbed flow model.
Results
The results of this study are the findings on the compressive modulus of the GelMA used for the research in the LUMC. The optimal curing time for achieving 10\%-15\% strain at physiological pressure levels (80-120 mmHg) was identified as 150 seconds, indicating a clear relationship between curing duration and GelMA's mechanical properties. The disturbed flow model improved the mean pressure to 113 mmHg, showing a more consistent pattern but with systolic pressure exceeding the desired range. Placing the sensor directly on the disturbed flow model improved results, suggesting potential improvements over the current IBIDI pump system waveform. The experiment targeted a total flow of 12 ml/min, similar to earlier experiments. It prevented cells from washing away from the GelMA substrate, with a split between inlets and outlets of 15\%-85\%. Initial runs used syringes for flow measurement, achieving a total flow of 11.8 ml/min, with a split of 1.8 ml/min and 10 ml/min, matching the desired split. With a pressure of 113 mmHg and total flow of 11.8 ml/min, the calculated total system resistance is 9.58 mmHg*min*mL-1 Peripheral Resistance Units (PRU), equivalent to 766 dynes*sec*cm-5 in cgs units.
Conclusion
This project successfully determined GelMA's possibilities in creating advanced in vitro vascular models, particularly under disturbed flow conditions. Through experimentation, GelMA demonstrated the ability to mimic native blood vessels' mechanical properties, offering improvements for future vascular research. Optimal conditions for GelMA were identified with a curing time of 150 seconds, resulting in a strain of 10\%-15\% under physiological pressures (80-120 mmHg). The fluidic test setup closely approached physiological pressures and allowed for two pathways resembling arteriovenous fistula (AVF) or bypass conditions. The correct flow of 12 ml/min and a split of 15\%-85\% was achieved. Determining systemic vascular resistance (SVR) contributes to setting up future experiments quicker and accurately within desired parameters.","mechanical characteristics; Disturbed flow model; GelMA","en","master thesis","","","","","","","","2026-02-01","","","","Biomedical Engineering","An in vitro bifurcated disturbed flow model for hemodynamics study on endothelial cells",""
"uuid:8d2b92dc-51e9-4d8e-b1d8-c9e7bac211e7","http://resolver.tudelft.nl/uuid:8d2b92dc-51e9-4d8e-b1d8-c9e7bac211e7","Dynamic wind farm flow control using free-vortex wake models","van den Broek, M.J. (TU Delft Team Jan-Willem van Wingerden)","van Wingerden, J.W. (promotor); Sanderse, Benjamin (copromotor); Delft University of Technology (degree granting institution)","2024","In the current state of model-based wind farm flow control, the implementation of yaw-based wake steering based on steady-state models has demonstrated potential for improving wind farm power production. However, for realistic, time-varying wind directions, the dynamics of wake propagation may impact the effectiveness of wake redirection. This dissertation presents the development of an economic model-predictive wind farm flow control strategy and assesses the potential for improved power production from wake steering in wind farms under time-varying conditions.
At the core of such a model-based control strategy is a control-oriented model of the wind farm flow. A free-vortex wake model is formulated based on an actuator-disc representation of the wind turbine rotor. A validation study is included for power predictions in the mid to far wake of turbines operating under yaw misalignment using data from wind tunnel experiments. Finally, a distributed strategy for control optimisation is constructed to provide a scalable solution for dynamic wind farm flow control which is tested in a large-eddy simulation environment under realistic conditions. This novel controller yields additional gains in power production during wind direction transients and reduces the increase in yaw actuator usage from wake steering.","wake steering; yaw misalignment; wind farm flow control; adjoint optimisation; economic model-predictive control; free-vortex wake","en","doctoral thesis","","978-94-6366-798-2","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:43c3b7dd-d007-4335-825b-768d0c70d5bf","http://resolver.tudelft.nl/uuid:43c3b7dd-d007-4335-825b-768d0c70d5bf","Reynolds-Averaged Navier–Stokes Simulations of Unyawed and Yawed Rotating Wheels","Alsudani, Ali (TU Delft Aerospace Engineering)","Modesti, D. (mentor); Delft University of Technology (degree granting institution)","2024","Aerodynamics has been an important aspect of the automotive industry for decades with the wheels being a notable contributing factor. They are responsible for up to 25% of the drag in the case of a general passenger car and up to 30%-50% for an open-wheeled race car.
In this research, the aerodynamic characteristics of an isolated rotating wheel in contact with the ground will be investigated using RANS simulations. Open-source software OpenFOAM is used for the simulations and the mesh is generated using cfMesh. The wheel geometry used in this work is the ""Fackrell A2"" and the contact region is modelled using the step size approach.
Firstly, the sensitivity of the step size, mesh fineness and domain size is assessed for an unyawed wheel and the k −ω SST, Realizable k − ε and Spalart-Allmaras are tested. Among these models, the Realizable k −ε model is chosen to investigate the effect of yaw and Reynolds number. The yaw is investigated up to 10° in increments of 2° and the Reynolds number effect is investigated for the Reynolds number range of 10 000 — 1 000 000.
The results show that yawing the wheel yields a fairly linear increase in the drag coefficient and the side force coefficient. Furthermore, only a significant increase of the lift coefficient is observed when going from a yaw of 4° to 6°. Moreover, the wake becomes asymmetric with increasing yaw. The vortex at the leeside on the ground becomes bigger while the vortex at the windward side becomes smaller. Additionally, a new vortex in the upper part of the wake further downstream is formed and the wake becomes shorter.
Increasing the Reynolds number, the value of the drag coefficient decreases and of the lift coefficient stays approximately the same. Moreover, the Reynolds number seems to affect the pressure peaks upstream and downstream of the contact patch. A lower value results in larger magnitude peaks. Finally, in the investigated Reynolds number range the wake structures are the same. However, the wake is bigger when the Reynolds number is smaller and asymmetry was observed in the wake for ReD = 1 000 000, which can be caused by the asymmetry of the wheel.
Both the integration and compatibility potential of the propellants and the propulsive and mass performance potential were investigated. The integration and compatibility potential were evaluated through a qualitative assessment based on non-performance-related propellant characteristics. Furthermore, eight fuels were subjected to a more detailed assessment covering the criteria of handling toxicity, environmental toxicity, material compatibility, handling and storage, development level, and coolant qualities. RP-1 was found to be the most suitable fuel with respect to the specific criteria, while ethanol, methanol, isooctane, and isopropanol were also found to be promising alternatives. A launch vehicle model was created to evaluate the propulsive and mass potential of twelve fuels proposed based on earlier findings. This model included a propulsion model, a mass and sizing model, and an aerodynamics and trajectory model, which were all connected through a global optimisation model. In terms of propulsive potential, the cryogenic propellant hydrolox was predicted to have a 25% higher vacuum specific impulse than the best-performing HTP-based propellant DMAZ/HTP. In terms of the specific impulse density, kerosene-derivative fuels in combination with HTP were predicted to have a better performance than hydrolox and than that other conventional storable propellant UDMH/NTO. The optimised gross lift-off mass for the launch vehicle concepts employing HTP was found to be 42-61% higher than the gross lift-off mass of Ariane 6 predicted through the model. Separately, the payload capability of the HTP-based launch vehicle concepts was predicted to be at least 38% lower. In both cases, RP-1/HTP was reported to be the HTP-based propellant with the best performance, while DMAZ, isooctane, and isopropanol could be regarded as suitable alternatives. All of these propellants also outperformed UDMH/NTO. Through a sensitivity analysis, it was discovered that up to 270kg additional payload could be taken to GTO upon considering elevated chamber pressures in the HTP-based engine design. In the end, the high potential and promise of HTP were confirmed as it was concluded that increased development efforts towards HTP-based storable bi-propellant rocket engines could not only lead to a promising alternative to cryogenic propellants but could also allow for the complete replacement of toxic hydrazine-derivative fuels.","Hydrogen peroxide; Launch Vehicle optimization; propellant; Trade-off Analysis; Trajectory optimisation; Analytical hierarchy process","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:57fe3082-7584-463e-99d7-e98e2b334d25","http://resolver.tudelft.nl/uuid:57fe3082-7584-463e-99d7-e98e2b334d25","Data Governance Challenges at Dutch Financial Services Firms","Koeleman, Friso (TU Delft Technology, Policy and Management)","Smit, A.C. (mentor); Zuiderwijk, AMG (mentor); Delft University of Technology (degree granting institution)","2024","In 2006 already, Clive Humby said: “Data is the New Oil!” and like oil, data needs “infrastructure” to be gathered, analyzed and used. This infrastructure is called data governance and it is essential in today’s data-driven era to ensure availability, quality and security of an organization’s data. This is especially true for financial services firms, which deal with massive amounts of highly-sensitive personal data, such as names, dates of birth and bank details, and operate in a highly regulated environment. Therefore, it is essential that any new data governance policies, such as a transition to a cloud-based data governance policy, are implemented as quickly and efficiently as possible. Research thus far has primarily focused on the importance of data governance and developing data governance models. However, the implementation of data governance proves to be not without its barriers. Some research has been done into what barriers organizations encounter when attempting to implement new data governance policies, but strategies to deal with these barriers have not been found in existing literature. Therefore, this research seeks to answer the question:
“How do managers at financial services firms in the Netherlands deal with the barriers to successfully implement new data governance?”
This thesis used a literature study, twelve individual interviews with PwC employees who were heavily involved in data governance implementation processes at financial services firms in the Netherlands and a focus group interview with experts from PwC to determine what barriers financial services firms face when they are implementing new data governance, which strategies they use to deal with these barriers and what key factors influence the decision-making in this implementation process. These three elements were then used to find the answer to how managers at financial services firms in the Netherlands successfully implement new data governance.
The research attempts to close the gap in the literature surrounding the general strategies that are used to navigate the barriers that inhibit (new) data governance implementation. Furthermore, it can help further identify which barriers (financial services) firms face when attempting to implement new data governance and aid in the development of more effective data governance framework. Additionally, the improved understanding of how financial services firms navigate the barriers that inhibit data governance implementation can help maintain trust in financial services firms and the financial system as a whole and it can aid in the development of more effective regulatory frameworks to increase how fast financial services firms are able to comply to them.
The barriers financial firms face to implementing data governance that were found in this thesis were sorted into four broad categories: “Organizational culture/structure”, ”Senior management priority”, ”IT performance” and ”Lack of information”. Examples of these barriers are: a “restrictive mindset”, “unfocused strategy”, “incompatible IT systems” or a “lack of information on technoliii
ogy”. The strategies the firms used to deal with these barriers were also sorted into four different categories: “Senior management vision/championing”, “Technological tools/skills”, “Stakeholder involvement/consensus” and the “Business case” strategy. Examples of these strategies are: “developing a global vision”, “standardization of technology”, “stakeholder involvement” and “building a broad business case”. A complete overview of the barriers and their corresponding strategies that were found in this thesis can be found in figure 4.1...
This research focuses on utilizing satellite data to determine sand wave characteristics. Satellites like Sentinel-1 and Sentinel-2 which are used in this research have global availability of data over multiple years at a 10 meter resolution. Sentinel-1 has a Synthetic Aperture Radar (SAR) which creates images by sending out microwave signals and recording the strength and the time delay of the returning signals. Sentinel-2 has an optical instrument which creates images by recording the reflected light from the sun on the earth's surface. Sand waves were detected through the change in Sea Surface Roughness due to the current interaction with the sea bed as described in the Alpers-Hennings Model. The difference in resulting sand wave characteristics between SAR and optical images were determined.
Three initial areas of interest off the coast of the Netherlands were chosen based on their different characteristics. Hoek van Holland contains short irregular sand waves. Holland Kust Zuid contains long regular sand waves. The third location is Alkmaar, which contains no sand waves and was used to determine the results of the methodology when a location has no sand waves present. The first step was to determine the environmental conditions necessary for sand waves to be visible in satellite images. Image collections for an area of interest over a set period of time were filtered based on the environmental parameters. These parameters include mean glint angle and cloud cover for optical images, and wind and current speed for both optical and SAR images. Threshold values were determined through literature. The wind speed should be between 3 and 12 m/s, the current speed should be greater than 0.4 m/s, and the mean glint angle for the latitude of the North Sea is less than 56 degrees. The image collection for the year 2021 for the three different areas of interest was filtered based on these parameters. The final collection after filtering was then manually checked for the visibility of sand waves. This number was lower than the initial filtered collection which means that there are additional factors that need to be accounted for.
A methodology was created to determine the sand wave characteristics over an area by applying a Fast Fourier Transformation (FFT) and calculating the sand wavelength and wave angle from the resulting signal. This was first applied to the three different areas of interest within the North Sea, Hoek van Holland, Holland Kust Zuid, and Alkmaar. Using the resulting image collection at these locations the sand wave characteristics were calculated. Although there are no sand waves at Alkmaar, due to the methodology, sand wave characteristics are still calculated. Also, the methodology works better at Holland Kust Zuid with long regular sand waves compared to at Hoek van Holland where sand waves are shorter and irregular.
To determine at which scale the satellite images should be viewed at to obtain information on the sand wave characteristics, the data was split into different area sizes and a FFT performed. The resulting average values and spread of the sand wavelength and wave angle were compared at different area sizes for optical and SAR images, as well as Multi-Beam Sonar (MBES). This resulted in an area of 5 by 5 kilometers which allows for the correct signals to be read across different possible sand wavelengths. Also, the effect of different sources of noise on the FFT and calculation of the sand wave characteristics for optical and SAR images was determined. From this it was seen that ships within a satellite image containing sand waves introduce a very strong signal within the FFT. This prevents the sand wave characteristics from being calculated correctly. Wind farms within a satellite image affect SAR images, and not optical images. Suspended sediment transport and clouds, which only occur within optical images, have different effects. Optical images are not affected by sediment transport because the current direction will always be perpendicular to sand wave crests and therefore does not influence the calculation of sand wave characteristics. Clouds, similarly to ships, introduce a strong signal within the FFT which blocks the signal of the sand waves. Dark patches (like rain cells), which effect SAR images, block the visibility of sand waves within satellite images and therefore there no signal corresponding to sand waves within the FFT can be found.
Then, the area of interest was increased to the entire southern North Sea. Satellite images over the North Sea were downloaded in 5 by 5 km tiles for a single satellite pass over per year where the environmental parameters met the conditions necessary to view sand waves. As for the local scale cases, a FFT was applied to each tile and the sand wave characteristics were calculated including sand wavelength, wave angle, density, and spatial frequency. The differences in characteristics were compared from year to year. Typically, the difference is less than 200 meters in sand wavelength, however there are points where the difference is much larger. This is due to noise affecting the calculated value. Additionally, the data for wind speed and current speed for the date and time of the satellite image was determined. From this it is seen that optical images can contain sand waves at lower wind and current speeds, at the lower end of the boundary conditions. Sand waves are only visible in SAR images when the current speed is very high. Also, the results were compared to the water depth of the North Sea. At depths less than 40 meters which occurs on the Dutch Continental Shelf sand waves are almost always visible with the correct environmental parameters. At depths greater than 40 meters, which occurs on the West side of the sand wave field, sand waves are not visible consistently. The calculated sand wavelength over the North Sea was also compared to wavelength obtained from MBES. This resulted in low correlation values for both optical and SAR. As a result, noise present in satellite images should be taken into account.
By both applying the methodology to smaller scale cases and to the entire North Sea, it is possible to detect sand waves in different environments. Using the change in sea surface roughness due to sand waves it is possible to see sand waves in both optical and SAR satellite images. By applying the Fourier transformation the average sand wave characteristics over an area can be calculated. The methodology is limited by environmental parameters and noise that can be present in the satellite images. SAR and optical images require specific wind and current conditions, while optical images also requires specific mean glint angles and a low cloud cover. Different sources of noise also have a negative impact, adding signals to the FFT that do not correspond to the sand waves. Although the methodology proposed in this thesis is successful in determining the average sand wave characteristics over an area, more research for this topic would increase the possibilities. This includes using additional conditions for filtering image collections for sand waves, removing sources of noise, utilizing higher resolution satellite data, and testing the methodology on different sand wave fields that have different characteristics, such as symmetry. There are still many possibilities that can be explored in using satellite images to determine sand wave characteristics.","Sand Waves; Remote Sensing; Satellite Imagery","en","master thesis","","","","","","","","","","","","Civil Engineering | Hydraulic Engineering","",""
"uuid:3010e904-f171-4a37-b75a-143be8750ab2","http://resolver.tudelft.nl/uuid:3010e904-f171-4a37-b75a-143be8750ab2","Towards Energy-Efficient Residential Buildings In Jeddah, Saudi Arabia: Exploring Energy Retrofitting Options And Assessing Their Feasibility","Felimban, Ahmed Abdulazeem (TU Delft Architectural Technology)","Knaack, U. (promotor); Klein, T. (promotor); Konstantinou, T. (copromotor); Delft University of Technology (degree granting institution)","2024","The thesis explores energy retrofitting options for enhancing the energy efficiency of residential buildings in Jeddah, Saudi Arabia. It identifies and validates cost-effective energy retrofit schemes that have the potential for energy savings. The thesis also assesses the feasibility of energy retrofitting scenarios for building envelopes and their impact on reducing energy consumption, improving thermal comfort, and mitigating the environmental impact of buildings. The results of this research can guide architects and decision-makers on energy-saving measures for residential buildings in Saudi Arabia, with Jeddah serving as a representative case study.","","en","doctoral thesis","A+BE | Architecture and the Built Environment","978-94-6366-803-3","","","","","","","","","Architectural Technology","","",""
"uuid:6afd744c-906a-430d-a573-4382492596b3","http://resolver.tudelft.nl/uuid:6afd744c-906a-430d-a573-4382492596b3","Model Predictive Control for a Heat Pump System with Thermal Storage Tanks: Economical Operation and Demand-Side Management","Tang, Weihong (TU Delft Mechanical, Maritime and Materials Engineering)","Keviczky, T. (mentor); Li, Y. (mentor); Walker, S. (graduation committee); Khosravi, M. (graduation committee); Delft University of Technology (degree granting institution)","2024","In light of the pressing challenges posed by global climate change and the imperative to reduce CO2 emissions, innovative approaches in energy management are critically important. This thesis presents an exploration of heat pumps integrated with Thermal Storage System (TES) systems, an area of research and application pivotal for enhancing energy efficiency and environmental sustainability. The combination of heat pumps and TES systems emerges as a key factor in reducing greenhouse gas emissions and optimizing the utilization of renewable energy. Such integration plays a crucial role in minimizing operational costs, reducing environmental negative impact, and augmenting system efficiency by enabling the storage and later use of energy from renewable sources. Moreover, this integration facilitates the effective management of demand-side energy, bolstering the capacity to incorporate fluctuating renewable generation into the energy grid. This is achieved by dynamically load shifting to balance energy supply and demand.
A central aspect of this thesis is the utilization of Model Predictive Control (MPC) for advanced energy management. The research delves into the use of MPC to optimize the operational economy of the system, aiming to maximize cost-efficiency. Additionally, an innovative MPC-based Demand-Side Management (DSM) strategy is introduced. This strategy involves two key steps: initially establishing a model to assess the system's energy flexibility, followed by harnessing this flexibility to respond to demand fluctuations. Such an approach facilitates dynamic adaptation to varying energy demands, ensuring optimal resource utilization. The predictive capability of MPC, which accounts for future disturbances including demand forecasts, electricity pricing, and weather conditions, is exploited to improve the system’s responsiveness and operational efficiency.
Experimentation was conducted both in simulations and through the implementation in real systems. These practical applications demonstrated significant savings in energy costs and energy consumption, achieving economical operation. Furthermore, the execution of the proposed two-step demand-side management strategy successfully managed energy demands. This not only underscores the practical effectiveness of the proposed system but also highlights its potential in real-world scenarios.
In summary, this research underscores how the integration of heat pumps, TES systems, and advanced control strategies like MPC can significantly improve energy efficiency, reduce operational costs, and enhance energy flexibility. It highlights the vital role of incorporating sophisticated control mechanisms into sustainable energy systems, aligning with the strategic goals of modern energy policies and advancing the field of sustainable energy management.","MPC; Heat pump; Demand Side Management; Model Predictive Control","en","master thesis","","","","","","","","2026-01-25","","","","Mechanical Engineering | Systems and Control","",""
"uuid:ad06b7b5-8467-4ca5-94b0-66218c9c4b32","http://resolver.tudelft.nl/uuid:ad06b7b5-8467-4ca5-94b0-66218c9c4b32","Towards a predictive maintenance strategy for Passenger Boarding Bridges at the airport","Meijs, Lester (TU Delft Mechanical, Maritime and Materials Engineering)","Pang, Y. (mentor); Negenborn, R.R. (graduation committee); Caspani, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","With Schiphol Airport's flight numbers growing, working assets are essential to ensure on-time processes. The Passenger Boarding Bridge (PBB) is a critical asset in the airport's turnaround process. By ensuring that the asset is working properly, the operational processes can run efficiently. Currently, improving the reliability of the PBB when in use happens after the fault has occurred. With this maintenance strategy, the PBB data is not used to predict the future health state of the PBB. Literature shows that the PBB can be classified as a multi-component system. Research in the predictive maintenance strategy of multi-component systems is still in an early phase. Research until now is more theoretical than practical, and an investigation into applying theoretical knowledge in practice is needed. With the upcoming developments of Industry 4.0, a Cyber-Physical System (CPS) architecture is proposed for a multi-component system. This architecture has been applied to the PBB to develop and use a predictive maintenance strategy for this system. Based on the implementation of a simulation model, the output showed that the proposed CPS architecture enabled the development of a predictive maintenance strategy for the PBB. With this strategy, proactive maintenance is planned while the system's reliability is held on a preset level to ensure a working asset during in-time use.","Predictive Maintenance; Cyber-Physical Systems; Passenger Boarding Bridge; Amsterdam Airport Schiphol; Prediction Model","en","master thesis","","","","","","","","2026-01-25","","","","Mechanical Engineering | Multi-Machine Engineering","",""
"uuid:05113292-4aaa-4600-9fc6-09fe556fbdc8","http://resolver.tudelft.nl/uuid:05113292-4aaa-4600-9fc6-09fe556fbdc8","Improving Access to Laparoscopic Bilateral Tubal Ligation in LMICs: A Novel Lifting Device with an Integrated Imaging System","den Butter, Robbert (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Medical Instruments & Bio-Inspired Technology)","Oosting, R.M. (mentor); Dankelman, J. (mentor); Diehl, J.C. (graduation committee); Horeman, T. (graduation committee); Iskander-Rizk, Sophinese (graduation committee); Delft University of Technology (degree granting institution)","2024","Background: Bilateral tubal ligation (BTL) is the most common method of contraception worldwide because it is safe and effective. However, its accessibility remains unequal among women in rural India, in part due to a lack of laparoscopic equipment. Rural hospitals therefore resort to gas insufflation-less laparoscopic surgery (GILLS) because it requires less complex equipment. The pneumoperitoneum is replaced by an abdominal wall lift (AWL) device, but these devices suffer from limitations concerning visibility and working space.
Methods: Initiated by the identified medical needs in rural India, a novel AWL device with an integrated imaging system is designed based on methods from literature and input from local end-users. It is a stainless steel hollow circular hook housing an LED lighting system and a 5 MP camera module. It can be connected to any laptop with a USB-A port. The device substitutes for both the traditional AWL device and currently used laparoscopes. The design is exemplified by a fully functional aluminium prototype used for verification and validation.
Results: The selected camera module is the key technology of this design because it provides state-of-the-art imaging at an unmatched price point. The lighting system used for the prototype does not provide enough light, has an asymmetric illumination distribution, and generates too much heat. A structural strength test showed that the strength of the prototype exceeds the material-adjusted design load by 30%. Furthermore, the prototype is cost-effective, lightweight, compatible with current AWL systems, and has limited waterproofness. User tests with an expert rural surgeon confirmed that this design has the potential to improve surgical outcomes of BTL and other procedures, and can increase access to specialized medical care in rural India.
Conclusions: It is strongly recommended to continue the development of this AWL device. The focus points should be the shape and size of the loop (and related cost-effective production techniques), a new lighting system, and the waterproofness of the device. Collaboration with rural surgeons and local biomedical engineers is crucial for context-driven development and implementation.","Gasless Laparoscopy; GILLS; Abdominal Wall Lift Device; LMICs; global surgery","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:6645b15b-ed31-45e6-b14d-96d516d23cf0","http://resolver.tudelft.nl/uuid:6645b15b-ed31-45e6-b14d-96d516d23cf0","Water Boards Navigating the Transition Towards Circular Use of Dredged Sediment","Loudon, Joséphine (TU Delft Technology, Policy and Management)","Pesch, U. (mentor); Quist, J.N. (graduation committee); Delft University of Technology (degree granting institution)","2024","This research critically examines Dutch water boards' journey towards the circular use of dredged sediment, set against the backdrop of water boards’ ambitious targets for circularity. Water boards, carrying the majority of responsibility for regional dredging, must navigate the surplus of approximately 40 million cubic meters of dredged material annually, with the declining availability of disposal permits. This has made the pursuit of circular solutions essential. Despite the central role of water boards in managing dredged material, particularly in freshwater contexts, there has been a lack of empirical study on how these actors are navigating and shaping the transition towards the repurposing of this material. As they confront this challenge, Dutch water authorities have set bold targets, aligning with national circularity goals: achieving 50% circularity by 2030 and reaching 100% by 2050.","Dredged material; Circularity; Water Boards; Discourse; Sustainability Transitions; Discursive Institutionalism","en","master thesis","","","","","","","","","","","","Industrial Ecology","",""
"uuid:9afc5dfc-fcf7-41a1-a66e-f23b3714326c","http://resolver.tudelft.nl/uuid:9afc5dfc-fcf7-41a1-a66e-f23b3714326c","Real-time Adaptive Nonlinear MPC for Collision Imminent Control and Planning in Automated Vehicles: Enforcing constraints and utilizing the full control potential","Trip, Kenrick (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Mechanical, Maritime and Materials Engineering)","Mazo, M. (mentor); Spaan, M.T.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","With the introduction of autonomous vehicles on public roads, their performance in emergency situations has become a strong focus. Collision Imminent Control (CIC) concerns the planning and control of aggressive evasive maneuvers for collision avoidance of automated vehicles. CIC is implemented using adaptive Nonlinear Model Predictive Control (NMPC), which considers obstacles and road barriers for combined trajectory re-planning and control. To achieve real-time performance, the prediction model complexity is often reduced, which can lead to an under-utilization of the control potential. The aim of CIC is to use as much of the control potential of the vehicle as possible while remaining real-time viable.
In this research, CIC is implemented using objective-based collision avoidance based on the distance to obstacles and road boundaries. Different collision avoidance formulations were derived and compared on accuracy and real-time performance. The control potential of the vehicle was further exploited by a computationally efficient vehicle model that employs differential braking. The NMPC problem is solved using Sequential Quadratic Programming (SQP) with Real Time Iterations (RTI). Different techniques that reduce the computation time were compared. Sparse solvers and variable timesteps were found to be most significant.
The robustness of the controller was improved by friction estimation. The controller is furthermore demonstrated to work on highly curved roads and in scenarios with dynamic obstacles. The controller is implemented on the hardware of a real autonomous vehicle and simulated on a closed-loop embedded system. Combining all these elements results in a CIC controller that can apply more control potential and reach control frequencies upwards of 100 Hz, increasing the level of safety in vehicle collision avoidance.","NMPC; Real-time control; Collision avoidance; Path planning; Autonomous vehicles","en","master thesis","","","","","","Double degree in Mechanical Engineering | Systems and Control and Electrical Engineering | Embedded Systems","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:ddcc3503-f815-4dd4-88b5-56076bf8f817","http://resolver.tudelft.nl/uuid:ddcc3503-f815-4dd4-88b5-56076bf8f817","Optimisation of the Absolute Sine for Dynamic Induction Control: Power Maximisation of a Wind Farm Through Infinite and Finite Horizon Control","Kuppers, Jean (TU Delft Mechanical, Maritime and Materials Engineering)","van Wingerden, J.W. (mentor); van den Broek, M.J. (mentor); Mulders, S.P. (graduation committee); van Vondelen, A.A.W. (graduation committee); Delft University of Technology (degree granting institution)","2024","The clustering of wind turbines in a wind farm results in overall efficiency losses as downstream wind turbines operate in the wake of their upstream neighbours. Wind farm flow control (WFFC) strategies have emerged to reduce these wake effects with the goal of maximising overall performance. Dynamic induction control (DIC) aims to enhance the wake breakdown and restore the wake's energy content through dynamic thrust variations. The control signals are often found through the economic model predictive control (EMPC) method, which relies on an internal model to incorporate future system behaviour in the determination of the next optimal control input. These models are designed to capture the most dominant wake characteristics while remaining computationally efficient. We employ the two-dimensional free-vortex wake (FVW) model presented from [1], which models the wake through vortex element pairs released from the edges of the actuator disc. The power of the two-turbine wind farm is maximised through EMPC, improving performance by 9.64\% over greedy control simulations. However, the EMPC method inherits finite horizon effects, resulting in large control horizons to optimise. In this study, we address these limitations by employing an absolute sine parameterisation in the FVW model to limit the finite horizon effects and reduce the dimension of the optimisation problem. The significant dimension reduction allows for a grid search to find the optimal infinite horizon steady-state solution, improving the mean steady-state performance by 2.43\% over the baseline results from [1]. Additionally, we focus on converging towards this optimum through finite horizon EMPC optimising over the amplitude and offset. Grid search analyses reveal sensitivity towards initialisation due to the appearance of local minima around the infinite horizon optimum. A maximum success rate is realised for very large control horizons, maximising the probability of converging towards the infinite horizon optimum. Accounting for the inherited system delay in the objective function also realises a maximum success rate but for shorter control horizons, which significantly decreases the simulation time. The final controller design terminates simulations ten times faster through the absolute sine parameterisation compared to the baseline simulation from [1] while maximising the probability of convergence towards the infinite horizon optimum.","","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:6d1f6c28-f4c3-4822-affa-7a761856cd07","http://resolver.tudelft.nl/uuid:6d1f6c28-f4c3-4822-affa-7a761856cd07","Influence of the slope angle on wave overtopping at rubble mound breakwaters","van Marrewijk, Jaap (TU Delft Civil Engineering & Geosciences; TU Delft Coastal Engineering; TU Delft Hydraulic Engineering)","van Gent, M.R.A. (mentor); Jumelet, D. (graduation committee); Mares Nasarre, P. (graduation committee); Delft University of Technology (degree granting institution)","2024","The objective of this research is to gather more information about a possible relation between the slope angle of a rubble mound breakwater and the wave overtopping at this breakwater. The following research question is covered in this thesis: What is the influence of the slope angle of rubble mound breakwaters on wave overtopping? To answer this research question, a literature study was done and physical model tests were performed at Deltares in Delft, the Netherlands. In total, tests to five different breakwater configurations were performed, with a slope of 1:1.5, 1:2, 1:4, 1:6 and 1:8. These breakwaters were exposed to varying significant wave heights and wave steepnesses. During these tests, the amount of water from waves overtopping the structure was collected in order to determine the average wave overtopping discharge for every performed test.
Results of this study show that the slope angle has a large influence on wave overtopping at rubble mound breakwaters. It follows that the steeper the slope, the larger the wave overtopping discharge for the same dimensionless crest freeboard. This trend was captured regardless the wave steepness. This relation can be seen V both for breaking and for non-breaking wave loading. However, the dependency between the slope angle and the wave overtopping discharge appears to be larger for breaking waves than for non-breaking waves.
Furthermore, it was found that the wave steepness has a large influence on wave overtopping at rubble mound breakwaters, both for non-breaking waves and for breaking waves. In general, it can be said that the lower the wave steepness, the larger the wave overtopping discharge for the same dimensionless crest freeboard. This relation was found regardless of the slope angle of the breakwater. However, it followed that the wave steepness has a larger influence on the wave overtopping discharge at gentle slopes, like 1:6 and 1:8. It should be noted that for non-breaking waves, the influence of the slope angle and wave steepness is not present in the existing manuals, while the effects are important.
The formulas in the current guidelines to calculate the wave overtopping discharge were compared to each other and the data. These formulas were further modified based on the data gathered during the physical model tests to obtain even more accurate predictions for overtopping discharges. This resulted in the proposal of two equations to calculate the average wave overtopping discharge at permeable rubble mound breakwaters for wave loading that can be characterized as breaking waves and non-breaking waves.
The backdoor attacks are mostly created to attack the classification models, where for each data sample, there is a label. In this thesis, we move away from the classification setup and create the first (to our knowledge) backdoor attack on the linear regression. We show that the triggers constructed using different versions of feature selection algorithms can be effective and impose a high error on the linear learning model prediction. Additionally, the study shows that backdoor attacks with the trigger constructed with a feature selection using correlation analysis lead to a higher error than the one using random forest for feature selection.
Furthermore, we also transfer this backdoor attack to the federated learning setup. The results prove to be highly dependent on the number of poisoned nodes, while for all of them, the error for the poisoned region is higher than for the clean data.
Finally, for the attack in both setups, we have adapted popular defence mechanisms that work against backdoor attacks on classification models. For the centralised setup, we have explored the possibility of using the studentized residuals as an outlier detection mechanism. The results are diverse, becoming worse when the poisoning rate of the model increases. To prevent the attacks in the federated setup, we used the FoolsGold defence mechanism, and it proved to be effective against the backdoor attacks on the regression model in all the cases except the one with exactly one attacking node.","Backdoor Attacks; Federated Learning; Machine Learning; Cybersecurity; AI Security; Linear Regression","en","master thesis","","","","","","","","","","","","Computer Science | Cyber Security","",""
"uuid:e277fd9e-7eb5-4af5-aff9-87dd166aed72","http://resolver.tudelft.nl/uuid:e277fd9e-7eb5-4af5-aff9-87dd166aed72","Project-Specific Cost Escalation Modeling: Crafting a Stochastic Tool for Predicting escalation: Modeling escalation","van der Kraan, Frenk (TU Delft Civil Engineering & Geosciences)","van Gelder, P.H.A.J.M. (mentor); Kammouh, O. (graduation committee); Morales Napoles, O. (graduation committee); Delft University of Technology (degree granting institution)","2024","Gaining insights into anticipated future expenses is essential for both the planning and construction phases of a project. A significant factor in future costs, particularly over extended periods, is the variability of material and labor prices. the change in costs over time, known as ’cost escalation,’ has been the focus of numerous research efforts. These studies primarily aim to forecast the Construction Cost Index (CCI), a composite index representing a standardized array of materials and labor typical in construction projects. This research presents a novel approach to forecast cost escalations, tailored to individual construction projects, addressing the shortcomings of predictions of a generic Construction Cost Index (CCI). Traditional CCI predictions, while providing some foresight, are limited by their generic nature and often overlook the specific material and labor variations within different projects. Additionally, current research generally fails to account for the uncertainty in the forecasts of the change in the material price and the estimate of the construction cost. In response to these challenges, this research pivots around the following research question: How can cost escalation for various types of construction projects be predicted, accounting for uncertainties in final construction costs and the forecast? Addressing this question involves selecting distinct indices for various project resources, such as steel, concrete, and labor, and combining these predicted indices in line with each resource’s cost. To achieve this, the study evaluates several time-series forecasting models, namely the vector error correction model (VECM), the vector autoregression (VAR) model, and the Holt-Winters model. For each model an automatic forecasting process is created, which automatically checks the suitability of the model, select the appropriate variables (in case of a multivariate model) and selects parameters. These models are evaluated for their accuracy across different time-frames and forecasting horizons. The Holt-Winters model, in particular, showed promise in providing reliable confidence intervals and point forecasts. The study’s testing phase revealed varying degrees of success, as volatile indices like copper and steel proved to be challenging, whereas forecasts for less volatile indices achieved higher accuracy. This outcome suggests room for improvement in refining these forecasting methods. The project-specific forecasts, including cost uncertainties, are developed by inputting cost estimates associated to the material price at current day value. The cost estimates input includes material and labor costs and their uncertainties. The uncertainties are represented through a three v point estimate (optimistic, pessimistic, and most likely values). This input is then transformed into a PERT distribution which is a transformation of the Beta distribution. The final stage involves combining the PDFs of each project activities cost (considering the cost of each specific resource) with the monthly forecast PDFs in a Monte Carlo simulation, providing a detailed cost distribution histogram of total cost and the individual resources cost. The tool’s functionality was demonstrated through a case study on a highway construction project. In this demonstration, specific project data, including material and labor cost estimates, were inputted into a hybrid web and Excel interface. This setup facilitates visualization and manipulation of project information. The tool processes these inputs via the AFP and Monte Carlo simulation, yielding comprehensive outputs such as histograms and statistical properties of the output. This is visible for total project costs and resource-specific escalations. This demonstration effectively showcased the tool’s capability to offer detailed insights into cost escalation, addressing the variability and uncertainty in construction projects. It underscored the tool’s alignment with the study’s objective of providing nuanced, project-specific cost escalation forecasts, moving beyond traditional CCI predictions. In conclusion, this study introduces a tool that caters to specific project resources, timelines, and uncertainties in cost escalations. While current limitations prevent its immediate practical application, this proof-of-concept lays the groundwork for future improvements. Focus of future research should be on refining accuracy and comparing the tool’s forecasts with escalation of historic projects to establish more robust insight into the actual escalation of projects.","cost escalation; Time-series modeling; Monte Carlo simulation; Econometrics; Programming; Cost management; project management; user interface; Predicting; Stochastic","en","master thesis","","","","","","","","","","","","Civil Engineering | Construction Management and Engineering","",""
"uuid:5c86f444-d625-432e-9fbb-188e67373929","http://resolver.tudelft.nl/uuid:5c86f444-d625-432e-9fbb-188e67373929","An integrated bicycle computer mount for aerodynamic handlebars: Development of a lightweight and aerodynamic solution for integration of bike computers into aerodynamic handlebars of professional road cycling bicycles","Kemme, Daan (TU Delft Industrial Design Engineering)","Jansen, A.J. (mentor); Tempelman, E. (graduation committee); Delft University of Technology (degree granting institution)","2024","The goal of this graduation thesis is to design a bicycle computer mount (BCM) that connects bike computers with road cycling handlebars in a visually appealing, and aerodynamic way. Initiated between Delft University of Technology and a leading sports equipment company, the project addresses the evolving needs of cyclists regarding maximum integration and aerodynamic optimisation of their material.
Through context research, user research and aerodynamic research, ideas were generated and formed into concepts. From those concepts the most promising was selected to further develop into a detailed design. This design was then validated with vibration tests, computational fluid dynamics (CFD) and finite element analysis (FEA).
The final design is a one-piece thermoplastic BCM that weighs 38 grams. It is made from injection moulded carbon-reinforced nylon (CF/PA12) to optimise weight and structural performance. A physical prototype was made for validation with different computers and vibration testing.","Bicycle computer integration; Bicycle product design; Product optimisation; Aerodynamic design","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:d7ce31ed-e4e6-4452-b54a-2f6dba9439c3","http://resolver.tudelft.nl/uuid:d7ce31ed-e4e6-4452-b54a-2f6dba9439c3","Mapping Discomfort through Patient Input in Robotic Physiotherapy","Ravenberg, Jevon (TU Delft Mechanical, Maritime and Materials Engineering)","Peternel, L. (mentor); Belli, I. (graduation committee); Stienen, A.H.A. (graduation committee); Della Santina, C. (graduation committee); Delft University of Technology (degree granting institution)","2024","In this work, we propose a method of processing patient input on discomfort level during robot shoulder physiotherapy into discomfort maps. These maps represent the patient's discomfort distribution throughout the range of motion of the shoulder, interpretable by both physiotherapists and robots. This method consists of three parts: the patient can input discomfort with a linear push-button; a collaborative robot arm is used to track the motion of the patient's shoulder; and audiovisual feedback of inputted discomfort is given to the patient and the therapist.
The method was validated in human factors experiments simulating shoulder physiotherapy sessions, where the subject is tasked with recreating a reference discomfort map through an auditory reference signal that emulates this discomfort. Here the robot also acts as the physiotherapist, moving the subject's shoulder. The signal is a beeping sound, whose rate scales with the discomfort intensity at the measured pose in the reference discomfort map.
We performed experiments with a total of 10 participants, demonstrating the viability of our method during patient-robot interaction. The results we collected also highlighted the presence of a time delay between the discomfort signal and the user input, and its effect on discomfort maps.","discomfort maps; shoulder rehabilitation; robot-assisted; Human-Robot Interaction; biomechanics; patient safety; patient feedback; physical therapy robot; shoulder; Impedance Control; patient input","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:1972d2ab-540b-4092-afd2-dbffa716283e","http://resolver.tudelft.nl/uuid:1972d2ab-540b-4092-afd2-dbffa716283e","Life cycle sustainability of novel monopropellant systems: A comparative LCSA of a LEO minisatellite case study","Deroo, Pepijn (TU Delft Aerospace Engineering)","Jyoti, B.V.S. (mentor); Wilson, Andrew R. (graduation committee); Delft University of Technology (degree granting institution)","2024","For over 50 years, hydrazine has been the industry standard for monopropellant propulsion systems, widely used in satellite attitude and orbit control systems. However, hydrazine’s toxicity necessitates expensive handling procedures and may lead to a future ban of the propellant in Europe. This has motivated the development of novel monopropellants, featuring reduced toxicity compared to hydrazine. Separately, life cycle assessments (LCAs) are becoming increasingly prevalent in the space industry. As very few assessments have been made so far for monopropellant systems, this thesis performs a comparative life cycle sustainability assessment (LCSA) of a hydrazine and three novel monopropellant systems for a single use case, evaluating the environmental, economic and social sustainability of each. This research provides new insights into the life cycle impact of the differences between the various propulsion systems and identifies hotspots in each sustainability dimension, informing a more sustainable development of novel monopropellant systems in the future.","Novel monopropellants; Life Cycle Assessment; Life Cycle Sustainability Assessment; Space Sustainability; space LCA; Non-toxic space propulsion","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:81b4473d-ea5a-4015-aefc-e7b56a9a44ef","http://resolver.tudelft.nl/uuid:81b4473d-ea5a-4015-aefc-e7b56a9a44ef","Flow analysis within the well dock of an LPD","Fotis, Konstantinos (TU Delft Mechanical, Maritime and Materials Engineering)","Pourquie, M.J.B.M. (mentor); Wellens, P.R. (mentor); Kalofotias, Filippos (graduation committee); Laskari, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","The Landing Platform Dock vessel is mainly designed to support amphibious operations in which landing operations play an important role. For operating landing craft the vessel has a well dock at the stern, designed to station several landing craft. Landing operations are restricted by the motions of the Landing Platform Dock vessel and by the motions of the water in the flooded well dock. Due to turbulent flow in the dock entrance and nonlinear wave motions inside the dock, the (dis)embarking procedure can be very hazardous for landing craft. Therefore it is necessary to execute this operation as safe as possible, meaning that the water motions in the well dock should be investigated thoroughly.
The primary objective of this thesis is to investigate how various physical mechanisms, when combined with wave characteristics, influence the flow within the well dock. The wave profile within the dock arises from the interaction of two physical mechanisms: radiation, caused by ship motions, and diffraction, which is observed when the ship remains stationary, causing incoming waves to diffract around its hull. Specifically, this study wants to determine which of the two physical mechanisms radiation or diffraction has a more pronounced influence. Also, it investigates how different wavelengths impact these mechanisms and the results combination of independently analysed mechanisms with a model that integrates both mechanisms from the start of the simulation.
The second objective centers on the development of an accurate and efficient model to capture the physical mechanisms of the flow within the well dock of an LPD. The validation for this model derives from model tests conducted at TU Delft[20].
The third objective focuses on simplifying the model in order to facilitate the design process. Upon validating the model from the second research question, wave kinematics are captured using a wave probe located at the dock entrance. These kinematics are then used as inputs for a 2D model. Notably, this model specifically represents the well dock and the ramp region, excluding the complete ship structure. For validation, the same procedure employed in the second objective is followed, referencing experiments conducted at TU Delft[20].
All Computational Fluid Dynamics (CFD) calculations were executed using the ComFLOW program.","Landing Platform Dock; ComFLOW; Physical Mechanisms; Well Dock; Fast Fourier Transformation (FFT); Time-Domain Signal; Design Modification; Ramp Region; Viable Model; Full Model","en","master thesis","","","","","","","","2026-01-23","","","","Mechanical Engineering | Energy, Flow and Process Technology","",""
"uuid:a4cf15dc-b4db-41ad-96c2-5e2cef9d7d9f","http://resolver.tudelft.nl/uuid:a4cf15dc-b4db-41ad-96c2-5e2cef9d7d9f","The Potential of Community Energy Storage for Grid Congestion and Prosumer Profitability in the Netherlands’ Residential Solar Market","Yousef, Gabriel (TU Delft Electrical Engineering, Mathematics and Computer Science)","Hakvoort, R.A. (mentor); Li, L. (mentor); Vergara Barrios, P.P. (mentor); Delft University of Technology (degree granting institution)","2024","With the phasing out of the Net Energy Metering (NEM) scheme, the energy market is shifting towards alternative solutions like independent energy storage, already successful in countries like Belgium and Germany.
However, a single solution dominating the market is unlikely due to continuous innovation and the limitations of individual battery systems for prosumers and Distribution System Operators (DSOs). Community energy storage (CES) emerges as a promising alternative but lacks a defined business model, particularly for Dutch residential communities.
This study delves into the implementation of centralized community energy storage systems to boost prosumer profitability and mitigate grid congestion in the Dutch solar residential market, in the wake of the NEM scheme phase-out. Community energy storage applications are identified, along with their respective potential business models. The optimal application, in terms of prosumer profitability and grid relief, is selected, and its associated business model is developed using the Morphological business model designed for energy communities. Furthermore, a practical approach for integration is proposed, based on regulatory and market constraints, to enhance the potential for large-scale emergence. This approach includes defining key roles and responsibilities of stakeholders within the community and the corresponding allocation of value. Subsequently, a technical system design topology is outlined for each defined community. This system design delves into engineering details to analyze the energy interaction possibilities between consumers and the grid, along with the corresponding financial implications. Accordingly, the CES application’s performance is simulated and evaluated both technically and financially. The potential is presented by simulating the interactions between the community, the grid, and the optimal battery system. This optimal interaction arises from an optimization problem formulated to provide the optimal battery size and its corresponding energy profiles that minimize the total community cost. Finally, an energy distribution mechanism is carried out through conditional decision making to evaluate the cost and profitability allocation among consumers within the community.
The findings highlights the optimal application of CES, combining energy sharing with energy arbitrage, which significantly enhances the value of prosumers’ surplus PV energy, outperforming standard tariffs and avoiding grid feedback charges. This approach also provides consumers with access to more affordable shared community energy, while aiding DSOs in alleviating grid congestion and improving infrastructure capacity. The study suggests that the most effective strategy for widespread CES adoption involves collaboration between housing cooperatives and Energy Service Companies (ESCOs). Financially, this model entails
community managers overseeing initial investments, complemented by household contributions via usagebased or fixed service fees. The business model’s success is influenced by the type of grid connection, with Behind-The-Meter (BTM) offering flexibility but lacking standardization, and Front-of-The-Meter (FTM) encountering challenges related to community energy taxation. Modelling the optimal operation for both BTM and FTM connections demonstrates a significant decrease of energy costs and contribution to grid relief, highlighting load smoothing and peak shaving as key benefits. The research concludes that centralized CES systems can substantially elevate prosumer profitability and reduce grid congestion, leading to considerable energy savings and enhanced grid performance in the Dutch solar residential market.
To support the expansion of Community Energy Storage (CES) systems and energy communities, policymakers are advised to revise energy taxation policies and create frameworks aiding community grid formation, including simplifying regulations and offering incentives for residential initiatives. Researchers should adopt a multidisciplinary approach to explore regulatory, technical, economic, social, and environmental impacts on CES, focusing on regulatory effects, grid dynamics, cost-benefit models, community engagement, and environmental benefits. Industry stakeholders, such as Distribution System Operators, energy providers, Energy Service Companies, and housing cooperatives, should apply these research insights to develop and implement CES systems, fostering partnerships to address challenges and innovate in energy solutions, particularly in the evolving landscape post-Net Energy Metering, to enhance the role of community storage in sustainable energy systems.","","en","master thesis","","","","","","","","","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:cd0f2c4b-45b8-44ca-b0b0-d58222254375","http://resolver.tudelft.nl/uuid:cd0f2c4b-45b8-44ca-b0b0-d58222254375","Hydrogen energy storage in porous media","Hashemi, L. (TU Delft Numerical Analysis)","Vuik, Cornelis (promotor); Hajibeygi, H. (promotor); Delft University of Technology (degree granting institution)","2024","The demand for sustainable and clean energy sources has become increasingly vital in addressing the challenges of climate change and energy security. Hydrogen, with its high energy density and potential for carbon-free energy conversion, has emerged as a promising candidate for future energy systems. Efficient storage and retrieval of hydrogen are crucial for its widespread utilization, for which a promising approach is underground hydrogen storage in geological porous media. This thesis aims to explore and advance the understanding of hydrogen storage in geological porous media, specifically focusing on pore-scale modeling and contact angle analysis.
This research aims to overcome the limitations of current hydrogen storagemethods and develop more efficient energy storage systems. Porous materials like sandstones have special characteristics that make them suitable for storing hydrogen underground. To design and operate underground hydrogen storage on a large scale, it is important to understand how fluids move through these materials. The way hydrogen is stored and released is influenced by complex processes happening at a very small scale (μm). To accurately simulate these processes, we need to study how fluids move in the pores, including factors like capillary pressure (the pressure difference between nonwetting and wetting phases, which is one of the main forces acting at pore scale transport) and relative permeability (how easily fluids flow through the pores where other fluids are also present).
Pore-scale modeling is a useful tool for simulating and understanding how hydrogen behaves in the tiny pore spaces of porous materials. These models help us see how hydrogen moves, spreads out, and interacts with the pore walls at a very small level. Another important aspect is studying the contact angles in the system of hydrogen, water, and porous material. These angles tell us about the way these substances interact at the interfaces between solids, liquids, and gases. By studying these processes and measuring contact angles, we can gain a better understanding of how hydrogen is stored and released, considering factors like pressure, temperature, the type of material, and how easily fluids flow through the pores. This knowledge will help us design better systems for storing hydrogen energy in porous materials on a larger scale.
The primary objectives of this thesis are as follows: To develop pore-scale models for simulating and understanding underground hydrogen storage in geological porousmedia. To investigate the contact angle between hydrogen, brine, and sandstone systems and their influence on storage and release mechanisms. To analyze the contact angle for a mixture of hydrogen-methane in the brine/sandstone system and assess its implications for hydrogen storage. To develop a dynamic pore network model to capture the dynamic behavior of hydrogen in geological porous media. To draw conclusions from the findings and propose future research directions in the field of hydrogen energy storage.
This thesis project delves into the study of optimizing the Flying-V's landing performance, emphasizing the necessity of reducing pitch attitude. High-lift devices, particularly split flaps, were explored for this purpose. Wind tunnel tests were carried out on a scaled-down model of the half- wing, in the Open Jet Facility of TU Delft. The tests yielded two successful flap configurations— a single-flap and a double-flap.
These were analyzed further using a flight performance tool to make a final selection on the flap configuration. The single-flap option proved effective in reducing landing pitch attitude by 3 degrees, significantly lowering obscured segment by 20 to 30 m and the pilot's eye altitude by 1 m. This is a quite desirable outcome for the landing performance of the Flying-V which significantly improves pilot’s vision.
The COVID-19 supply disruptions and the energy crisis triggered by the Russian-Ukrainian conflict emphasize the EU's structural supply dependencies and potential damages during crises. It underscores the critical risk factors, particularly Rare Earth Elements (REEs), which are highly susceptible to supply disturbances due to their increasing demand, limited supply, and reliance on a few suppliers, notably China. REEs are contrary to their name quite abundant, however, their extraction and processing are environmentally intensive, complex, and expensive. These REEs are utilized in numerous applications, including applications used in the energy transition because they exist in the Neodymium-Iron-Boron permanent magnets (Nd-Fe-B PMs). These magnets are used in wind turbine generators and traction motors of EVs. In these technologies, magnets are necessary to convert electricity into kinetic energy in EVs and vice versa for wind turbines.
This thesis focused on understanding how the EU can bolster its autonomy regarding its access to REEs, counterbalance supply risks, examine existing strategies, evaluate their effectiveness, and identify additional institutional interventions to strengthen the EU's position. This led to the following main research question:
How can the European Union improve its autonomy regarding its access to rare earth elements to achieve material security in the context of the European Union's energy transition?
The qualitative approach was chosen as the most suitable design approach to answering this main research question. It enabled a nuanced understanding of the EU's REE dependency issue by considering multiple dimensions and facilitated the development of well-informed and contextually grounded institutional interventions. The findings are triangulated between a literature review, desk research, and semi-structured depth-interviews with seven experts in this field.
This study performed REE value chains, actors, institutions, and PESTEL factor analyses. These four analyses offered a multifaceted insight into the complexities and interactions within this domain. Moreover, the illumination of various perspectives enhanced the overall comprehensiveness and facilitated a more holistic view of the EU's quest for enhanced REE autonomy.
Findings
Regarding the global REE value chain, China's unparalleled dominance, facilitated by generous lines of credits and subsidies, strategic partnerships and initiatives, geopolitical influence, manufacturing capabilities, technology, infrastructure, low labor cost, and lax environmental regulations, presents significant challenges. China's extensive control, especially in REE processing and Nd-Fe-B PM manufacturing, underscores the complex global dependence on China’s REE industry. The critical issues identified include a single third country supply dependency, rising demand for Nd-Fe-B PMs, challenges in recycling and circularity, high cost, stringent environmental regulations, and the need for skilled labor. These concerns, especially during the processing stage, underscore the complex barriers to achieving a resilient REE supply chain.
Globally, the REE landscape is predominantly shaped by China and the US. China maintains its pre-eminence through strategic initiatives, while the US is actively trying to close the gap. Acknowledging the imperative of strategic autonomy, the EU has instituted ambitious regulations, exemplified by the Critical Raw Materials Act (CRMA) and the Net-Zero Industry Act. These regulations established industry benchmarks for domestic extraction, processing, and recycling. However, the effectiveness of the CRMA in ensuring robust REE supply security is questionable.
The legislation lacks clarity on achieving and implementing industry benchmarks, presenting significant challenges in compliance, environmental and societal impacts, navigating shortened lead times for permitting, and addressing hurdles in private investment and fiscal alignment.
Institutional Interventions
This research identified enabling and constraining factors for the EU's autonomy regarding REE. Whereafter institutional interventions were created to cope with these issues. To achieve enhanced autonomy regarding REE access, five main strategies and several interventions are suggested. Conclusively, it is vital to note that the approach here is not a binary choice between strategies; rather, it necessitates the integration of a synergistic blend of the five proposed strategies.
Firstly, ‘Supply Diversification’ addresses the introduction of incentives for private demand for diversification, and the enhancement of strategic partnerships with REE-rich, EU-friendly countries.
Secondly, ‘Domestic Supply’ discusses: regulations incentivizing internal capacity; levelling the playing field; including Nd-Fe-B PM domestic manufacturing benchmarks; raising public acceptance; expanding funding; standardizing long-term contracts; and introducing low-energy zones.
Thirdly, ‘Circularity’ Encourages Nd-Fe-B PM demand reduction; incentivizes EoL practices; establishes CRMA PM labeling requirements; sets Nd-Fe-B PM collection targets; provides incentive structures; standardizes circularity by design; introduces extended producer responsibility; expands support programs; and impose an export ban on EoL Nd-Fe-B PMs.
Fourthly, ‘Substitutes for Nd-Fe-B PMs’ proposes: an increase in funding for R&D and innovation; and incentivizes substitutes for EV and wind turbine applications.
Fifthly, ‘Strategic Stockpiling’: addresses deficiencies in communication, transparency, and clarity by investigating obligation possibilities for Member States to monitor and strategically stock Nd-Fe-B PMs
Furthermore, the European Commission is instructed to consider introducing sub-benchmarks per individual CRM, improving understanding within governmental entities, increasing overall investment, and acknowledging the criticality for the EU to extend its policy horizon beyond 2030, given the long-term impacts of most proposed options. Moreover, EU policy alignment between Member States is critical, especially for creating an EU-level playing field for internal capacity and circularity. Enhancing autonomy in the realm of Rare Earth Elements (REEs) poses significant challenges, yet this thesis equips policymakers with essential findings and tools to navigate and improve access to REEs.
Consequently, the central question centers on assessing whether the positive impact on speech perception justifies the potential negative consequences for auditory spatial awareness. In this master’s thesis project a new test design was created to evaluate the speech perception and spatial awareness of children with cochlear implants in an ecologically valid classroom environment.
Methods: This master’s thesis project aimed to develop a test that was both ecologically valid and reproducible, focusing on the evaluation of three distinct conditions: Autosense on, Autosense off, and a remote microphone. Eligible participants for the study included children with cochlear implants aged between 5 and 18 years. The study utilized a virtual reality classroom environment, incorporating acoustical parameters of a real classroom setting into a 12-array loudspeaker setup. Assessment of frontal speech perception in noise was done with the digits-in-noise (DIN) test, while spatial awareness was assessed through the presentation of animal stimuli from various directions. Additionally, a randomly presented ice cream truck during the session served to evaluate environmental sound awareness (ESA). A pilot study was conducted on students, adults with cochlear implants and normal hearing children to validate the test method and fine-tune the levels of spatial awareness stimuli.
Results: The pilot study validated a virtual classroom setup for speech perception and spatial awareness in children with cochlear implants. Results from 14 participants, consisting of students, normal hearing and cochlear implant individuals, were included for test validation. Initial findings showed clarity in instructions, no adverse effects with virtual reality glasses, and comparable speech-in-noise scores in individuals. Spatial awareness tasks displayed a ceiling effect, leading to adjustments in stimuli levels. Psychometric curves for spatial awareness stimuli levels varied among cochlear implant individuals,
complicating the correlation between speech perception and spatial awareness. The test method proved suitable for normal hearing children, highlighting adaptability and ecological validity.
Conclusion: The results of this pilot study indicate the feasibility of the test for children with cochlear implants aged between 5 and 18 years. Regarding spatial awareness levels, it is recommended to use -5 dB and 0 dB SNR, with the goal of reducing the likelihood of floor or ceiling effects.","Cochlear Implants; Virtual Reality; Technical medicine","en","master thesis","","","","","","","","2025-01-15","","","","Technical Medicine","",""
"uuid:71500cd9-d2e3-4c02-8aca-63edad0638b2","http://resolver.tudelft.nl/uuid:71500cd9-d2e3-4c02-8aca-63edad0638b2","Synthesis of Nonlinear Torque-angle Profile Using Compliant Helicoidal Shell Joint","ABOUHEIDARI, SINA (TU Delft Mechanical, Maritime and Materials Engineering)","Radaelli, G. (mentor); Herder, J.L. (graduation committee); Delft University of Technology (degree granting institution)","2024","Compliant mechanisms, particularly helicoidal shell joints, present intriguing possibilities in mechanical design with applications in medical devices, robotics, automotive, and aerospace engineering. This research focuses on the synthesis of nonlinear torque-angle profiles using a compliant helicoidal shell mechanism such as gravity-balancing profiles. This study required a thorough exploration of the mechanism’s diverse design variations through Finite Element Modeling (FEM) and more specifically, Isogeometric Analysis (IGA). Subsequently, a targeted optimization process is utilized, incorporating both global geometric parameter adjustments and localized modifications by using splines. The prominent challenge addressed is the synthesis of gravity balancing torque-angle profile, achieved by tailoring the output profile of a compliant shell mechanism through optimization. Considering the inherent sine function output of a pendulum during gravitational equilibrium, an algorithm is developed to optimize the mechanism’s behavior to align with a sine function, hence enabling gravity balancing. Additionally, experimental validation was undertaken through manufacturing prototypes and conducting measurements to provide a crucial link between simulations and real-world behavior. The results of this research, encompassing optimized geometry and experimental data, are presented, and comprehensively discussed. This research contributes a numerical methodology that utilizes isogeometric analysis and optimization algorithm within the framework of finite element analysis for achieving nonlinear torque-angle profiles in complaint helicoidal shell mechanisms, such as gravity balancing profiles, offering valuable insights for possible applications in various engineering domains.","Compliant Mechanisms; Compliant Shell Mechanisms; compliant joints; tunable joints; compliant revolute joints","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Mechatronic System Design (MSD)","",""
"uuid:fa4f7239-d829-41aa-8cd4-f92c1a874a5e","http://resolver.tudelft.nl/uuid:fa4f7239-d829-41aa-8cd4-f92c1a874a5e","Circular performance of project equipment: The material circularity and economic value of project equipment on a project, product, and company level","Rodermond, Timo (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Marine and Transport Technology)","Pruyn, J.F.J. (mentor); Kana, A.A. (mentor); Delft University of Technology (degree granting institution)","2024","The global awareness of the environmental and economic advantages of the circular economy (CE) concept has grown significantly. In order to implement this concept into company practices, a vital starting point is the adoption of a measurement framework. In the past years, the evolution of CE metrics resulted in maturity and practical applicability. However, no method exists able to quantify CE performance specific to a project-based organization. The Material Circularity Indicator (MCI) is one of the most ambiguous methods, which captures circularity with mass as the measurement unit. Alternatively, the Material Circularity Indicator based on economic value (MCI’) is developed as a solution for the reliance of the MCI on mass flow, by using cost-based economic value as the measurement unit. However, existing economic value indicators — as accounts for the MCI’ — are criticized for not including all significant and relevant life cycle cost factors. To solve these implications, both methods are adapted to indicate the CE performance on the levels of interest for a project-based organization: the project, product, and company level. To work from level to level, a bottom-up approach is taken, aggregating using a weighted sum. Additionally, the MCI’ is enhanced by including more life cycle cost factors. The results show that the enhanced MCI’ gives a more accurate estimate of cost-based economic value. Furthermore, the aggregation from the project level to the product and company level, gives valuable insights into the CE performance of project-based organizations.","circular economy; Circularity; Circularity assessment; Material Circularity; Material Circularity Indicator; Economic valuation; sustainability; Project-based organizations; Equipment","en","master thesis","","","","","","","","","","","","Marine Technology | Maritime Operations and Management","",""
"uuid:557222bc-36a2-42e9-857a-e315a3d841de","http://resolver.tudelft.nl/uuid:557222bc-36a2-42e9-857a-e315a3d841de","Characterisation of frictional behaviour at brick-mortar interface","Karthick Sasikumar, K (TU Delft Civil Engineering & Geosciences)","Esposito, R. (mentor); Cabboi, A. (graduation committee); Dieudonné, A.A.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Unreinforced Masonry, a popular construction material with a rich historical legacy, has been resilient through centuries, despite its susceptibility to failure through various loading conditions such as seismic forces. Understanding the mechanical behaviour of masonry, particularly the cohesion and frictional mechanisms at interfaces between bricks and mortar, is crucial for assessing its structural reliability.
This thesis presents an experimental study characterising masonry frictional interfaces using a tribometer test, a novel approach in masonry research. The study aims to investigate the frictional behaviour of brick-mortar interfaces under varying precompression levels and test frequencies (3 Hz and 0.2 Hz). A novel sampling method was implemented, wherein the required specimens were extracted from a bonded masonry couplet specimen. The couplets were bond wrenched and then subjected to a mechanical extraction. Bond wrenching, through tension, separates the couplets, thereby isolating frictional response from the influence of cohesion by decoupling cohesion between the unit and joint. A tribometer was chosen for the investigation of frictional parameters, tribometers are typically employed with metal surfaces and rarely applied to masonry. Consequently, experiments were conducted using a reciprocating tribometer, featuring a novel specimen extraction procedure and a modified setup. The novel extraction involved mechanically altering a parent brick couplet to extract compatible specimens. Customised holders were procured and used to accommodate the prepared specimen. The obtained specimens were then, fastened into the appropriate sample holders. Tests were performed on the specimen with displacement, tangential force, normal force and time being recorded. Three key parameters, the mean Coefficient of Friction (CoF), the Energy Coefficient of Friction (ECoF), and tangential contact stiffness were analysed from the collected data. The above mentioned parameters were evaluated through two approaches, (i) Mean Curve approach and (ii) Cycle approach. A mean curve is the averaged curve of the measured hysteresis loop, which encompasses the overall behaviour exhibited by the hysteresis loop.
The experimental results revealed a dependency between the coefficient of friction and the applied pre-compression level, showing a non-Coulomb behaviour; this is in contradiction with assumptions of several models used for the analyses of masonry structures. Initially, experiments were conducted at a higher frequency (3 Hz) and followed by experiments at a lower frequency (0.2 Hz), and the results in both cases revealed a non-Coulomb friction behaviour characterised by a nonlinear connecting trend between kinetic and static friction region. The connecting trend between the kinetic and static region demonstrated a reduction in the degree of non-linearityan enhanced symmetry in the hysteresis profile as the precompression levels increased. The mean curve and the cycle approach yielded identical estimates for the coefficients of friction (CoF) and effective coefficients of friction (ECoF).
The evolution of Coefficient of friction (CoF), did not exhibit any clear systematic time dependency, while Energy Coefficient of friction (ECoF) showed a systematic decrease over time. The ECoF related the energy dissipated by friction across each cycle to a hypothetical Coulomb energy dissipation. Therefore the ECoF captures the energy dissipation due to friction during one cycle, while the CoF captured the static friction region. The energy dissipation across different precompression levels were also studied and it was observed that the energy dissipation increased for increasing precompression levels.
Tangential Contact stiffness refers to the tangential force required to effect a unit displacement in the tangential direction. The contact stiffness was calculated from the slope of the region of the hysteresis loop associated with displacement reversal. Contact stiffness was observed to increase with increasing precompression levels. This observation was also validated by the theoretical model which illustrates a proportionality between the applied normal load (precompression) and tangential contact stiffness.
Additionally, the study highlights the impact of frequency on the observed frictional behaviour, noting more prominent static and kinematic components at lower frequencies due to reduced inertial forces. A preliminary study using the LuGre model was used to plot the analytically derived frictional force-velocity relationship, to briefly study the impact of sliding velocity on frictional force. It was deduced that the velocity had an influence over the frictional force at the interface.
In conclusion, the findings provide valuable insights into the frictional characteristics of masonry interfaces under varying loading conditions. The results also shed light on the practical aspects of testing methods and offer considerations for further research in the field of masonry engineering.
Despite the benefits provided by the MMC-based MTDC system, various technical problems emerge. For example, in case of a DC fault on HVDC transmission lines, the DC voltage suffers a deep sag, and the fault current increases to the peak value after several milliseconds, the system stability is seriously affected. The fault currents will easily damage the power electronics and may lead to a collapse of the entire system if the faults are not cleared promptly. Thus, it is crucial to implement a fast, selective, and reliableDC fault protection technology in the system for fault detection. Once the fault is cleared, it is important to know the exact fault location to repair the faulty sections and to restore the system. Hence, an accurate DC fault location technique is of utmost importance for the MTDC system, which would significantly minimize electricity loss and expedite the system restoration process in the event of power outages. In addition, there is a lack of standardization in MMC control, and the majority of HVDC projects are constructed in a vendor-specific manner. As of today, it is unclear how MMC converters from different manufacturers will interoperate with each other. These pose new challenges to the performance of HVDC protection and MMC control and need to be addressed to manage, safeguard, and accelerate the practical feasibility of this system.
The research in this thesis aims to address the shortcomings that have not been addressed in the state of the art, mainly related to the challenges arising when DC faults occur in the MMC MTDC systems and, as such, could provide promising solutions for future practicalMTDCapplications. The main topics areMMC control&interoperability, Protection, and Fault location for the MMC-based MTDC system. The thesis deals with designing a robust protection scheme, a fault location method, and an investigation of the interoperableMMC controllers...
To date, however, the potentially confounding effects of both internal and, particularly, external water dynamics in vegetation on radar backscatter have not been adequately addressed. Existing studies have indeed illustrated the effects of SCW on radar backscatter, but the degree to which it influences different frequencies and polarizations, and the subsequent impact on crop bio-geophysical parameters remains unclear. Therefore, the main goal of this thesis is to expand our knowledge of the relationship between radar backscatter, vegetation dynamics, and surface canopy water (SCW) in agricultural monitoring. In this thesis we utilized statistical analysis and radiative transfer modeling in combination with fully polarimetric L-band data from a truck-mounted scatterometer and C-band data from Sentinel-1, along with extensive field data…
electrically characterized. These measurements allow the development of an RF power compensation system, leading to an increase of applied power at the level of each transducer. Hence, the absorbed power at transducer level increases, resulting in improved optical diffraction efficiency.","AOTF; RF-steering; compensation; VSWR","en","conference paper","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-01","","","Space Systems Egineering","","",""
"uuid:c9819e3b-0c02-437f-9c63-8ed84e978032","http://resolver.tudelft.nl/uuid:c9819e3b-0c02-437f-9c63-8ed84e978032","Optimal Strategies of Autonomous Reconnaissance Missions","Verlinde, Lander (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Discrete Mathematics and Optimization)","Jurrius, R.P.M.J. (mentor); de Laat, D. (graduation committee); Delft University of Technology (degree granting institution)","2024","The role of Unmanned Aerial Vehicles (UAVs), more commonly known as drones, in society continues to become more significant every day, both in everyday life and in military operations. The extent to which unmanned vehicles are used for both offensive as well as reconnaissance missions is at an all-time high. To expand the number of operational systems while managing costs, it is desirable to deploy systems that can operate fully independently. For a survey mission, this requires a planning of the complete mission before the drone leaves for enemy territory. The setting of such a mission can be stated as follows: starting from a secure base, multiple surveillance locations need to be safely reached and the acquired information has to be transmitted back to the base. There are many possible strategies for gathering this information. This report investigates how to find the strategy that maximises the expected amount of retrieved information. Specifically, such an optimal strategy tells us which route the UAV should take in enemy territory and at what moments in the mission transmissions should be made. We present a mathematical framework for formulating the problem, as well as a genetic algorithm capable of finding the optimal strategy in different scenarios.","Mission Planning; Genetic programming; Vehicle Routing","en","student report","","","","","","This report is the result of my three month long internship at the Netherlands Defense Academy as part of the Master Program in Applied Mathematics.","","","","","","Applied Mathematics","",""
"uuid:cb151adc-b413-424e-9dda-4fa30e759a1a","http://resolver.tudelft.nl/uuid:cb151adc-b413-424e-9dda-4fa30e759a1a","theatre of the city: theatre that’s a part of the city. city that’s a part of the theatre","Alexandrov, Artem (TU Delft Architecture and the Built Environment)","van de Pas, R.R.J. (mentor); Staničić, Aleksandar (graduation committee); van den Ban, R.R. (graduation committee); van den Burg, L.P.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Engagement with the city in provincial Russia is currently lacking a framework of care for the historical urban fabric. Listed buildings decay with no revitalisation plans made by the municipality or the citizenry. On the other hand, theatre in modern-day Russia is an acknowledged political entity – a pocket of free(er) thinking and civil engagement. This research studies the historical trends in theatre to define the spatial qualities of audience engagement. The goal is to harness such qualities and apply them to a dilapidated building in Rostov-on-Don, reconnecting it with the city and the citizens, and hopefully begin a revival process all over the historic city centre.","Theatricality; heritage; civil engagement; monument; Russia; regional","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Explorelab","","47.21492394418736, 39.71322245169227"
"uuid:6b61f0b5-e5e6-4a83-a18b-107d01f5d1c8","http://resolver.tudelft.nl/uuid:6b61f0b5-e5e6-4a83-a18b-107d01f5d1c8","Optimization of BPMED for the recovery of ammonia and citric acid from ammonium citrate scrubber effluents by response surface methodology","Huang, Wenqing (TU Delft Civil Engineering & Geosciences)","van Lier, J.B. (graduation committee); Spanjers, H. (mentor); Vermaas, D.A. (graduation committee); Mutahi, G. (mentor); Delft University of Technology (degree granting institution)","2024","The excessive nitrogen in waterbodies, often caused by the discharge of ammonia-rich wastewaters, leads to eutrophication, disrupting aquatic ecosystems. Wastewater treatment plants play an important role in the removal and recovery of nitrogen from wastewater streams, thereby preventing pollution. Air stripping in combination with acid scrubbing has emerged as a promising technology not only for removing ammonia from wastewater, but also for recovering it as a valuable fertilizer, ensuring circularity. However, factors such as continuous consumption of chemicals and the hazardous use of strong acids need to be addressed. To reduce chemical consumption, a combination of air stripping and organic acid scrubbing with bipolar membrane electrodialysis (BPMED) has been proposed.
This study focused on optimizing BPMED for the recovery of ammonia and citric acid from ammonium citrate scrubber effluents. The impact of current density, membrane configuration, feed solution characteristics (pH and initial N concentration), and temperature on recovery efficiency, current efficiency, and energy consumption of a BPMED system was evaluated. The limiting current density (LCD), a key factor in the normal operating range of the system, was determined using the Cowan and Brown method, yielding a critical value of 1.01 A/m2.
Comparative experiments conducted on three BPMED configurations, including 3-chamber BPMED (BPCA), 2-chamber base BPMED (BPC), and 2-chamber acid BPMED (BPA), revealed the superior performance of the BPC in terms of current efficiency, energy consumption, and running time. The optimal operating time of BPC was determined to be 120 minutes, achieving a recovery efficiency of 55.9%, a current efficiency of 44.2%, and an energy consumption of 8.4 kWh/kg-N.
Moreover, regression models were established using Box-Behnken design (BBD) from response surface methodology (RSM) to optimize operating conditions (pH, initial N concentration, and temperature), maximize recovery efficiency, current efficiency, and minimize energy consumption. Verified by analysis of variance, normal probability plot, and residual analysis, the model showed high accuracy and significance.
Univariate analysis elucidated that pH and initial N concentration were found to be important variables, while temperature was not. Increasing pH (3–7) enhanced recovery and current efficiency while decreasing energy consumption. Higher initial N concentrations (2–10 g/L) improved current efficiency, decreased energy consumption, but reduced recovery efficiency, emphasizing the need for a careful balance. Temperature variations (20–40°C) had no significant impact on BPMED. Critical factors limiting ammonia recovery efficiency, current efficiency, and energy consumption were identified, including solution conductivity, H+ ion leakage, water migration, and NH3 diffusion.
Furthermore, the study revealed non-significant interactions between these variables through 3D response surface plots and 2D contour plots. Adjusting operational variables proved feasible for optimizing performance indicators. The optimized conditions (pH 6.05, initial N concentration 6.67 g/L, temperature 30°C) were experimentally verified, and the predicted values were in good agreement with the actual values, confirming the reliability of the optimization model. Specifically, the recovery efficiency was 52.9%, the current efficiency was 45.4%, and the energy consumption was 7.0 kWh/kg-N.
Energy evaluation of the BPMED system in BPC configuration under optimal conditions showed significant energy efficiency. Based on the comparison with the available literature, the integration of BPMED with air stripping and organic acid scrubbing could improve energy efficiencies and lower chemical consumption while offering a closed-loop system.
Future research should explore principles to inhibit ion leakage and water migration, analyze the combined effects of various operating variables using RSM, and validate the potential for lower energy consumption in full-scale BPMED. Developing continuous BPMED processes is crucial for full-scale application, and integrating BPMED with other processes such as air stripping and acid scrubbing may enhance ammonia recovery and production efficiency.
The insights gleaned from this study provided a solid foundation for enhancing ammonia recovery processes from ammonium citrate scrubber wastewater, thereby promoting sustainable and resource-saving industrial practices.
In this thesis project, a drone is designed, built, and programmed to navigate autonomously in the rainforest with complete onboard computing and no GPS localisation. This 500-gram drone is being extensively tested and optimized in real forest conditions, and a dataset is being created from its autonomous flights to simulate various configurations of the path-planning algorithm. The results of these simulations on this dataset are then used for thorough research on how the algorithm can downscale to smaller systems and how this affects performance.
By using the results of this research on downscaling, a 100-gram drone is built and programmed to fly in forest conditions with complete onboard computation. Challenging on this small-size drone is the use of low-quality lightweight sensors and processor. The processor only weighs 10 grams, and the depth camera weighs 8 grams. Unique on this small drone is the 3D path planning fully computed onboard and the implementation of a new type of depth camera.","autonomous navigation; drone; downscaling","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:7dcddaae-dad1-4804-bf5b-c8706e4e2e59","http://resolver.tudelft.nl/uuid:7dcddaae-dad1-4804-bf5b-c8706e4e2e59","An Area and Energy Efficient Arithmetic Unit for Stacked Machine Learning Models: Mo Model Mo Problems Like... Hardware Design Problems","van der Kolk, Floris (TU Delft Electrical Engineering, Mathematics and Computer Science)","Hamdioui, S. (mentor); Gebregiorgis, A.B. (graduation committee); van den Berg, René (graduation committee); Delft University of Technology (degree granting institution)","2024","Machine learning on edge devices performs crucial identification or prediction tasks while limiting the amount of data that needs to be transmitted to more centralized computing nodes. However, strict area and energy requirements necessitate specialized hardware developed for the requirements of the device and model. This thesis is concerned with developing an area and energy arithmetic unit as part of the implementation of a stacked machine learning model in embedded automotive devices. The model in question was previously designed to perform lifetime prediction with the goal of improving the reliability of semiconductor devices used in various automotive applications.
This thesis aims to achieve area and energy efficiency by exploiting the commonalities in the arithmetic operations of several of the internal learners of the stacked machine learning model. The use of a weighted figure of merit, taking into account area, energy and delay, allow for simple comparisons of designs at any operation frequency and easy insight into the changes in the merit of designs if device requirements were to change. A sweep of the percentage of multiplications in the workload also gave insight into how design choices may change due to future redesigns of the stacked machine learning model.
It was found that the MAC, multiply, divide and accumulate operations of the internal learners can best be supported by one arithmetic unit containing a ""Reduced Area"" parallel multiplier (still taking up most of the area), a small, dedicated accumulator and invariant integer division using the multiplier. It was also found that the ability to reconfigure the multiplier for different levels of bit-precision does not yield performance improvement for the expected precision distribution.","Machine Learning; Computer Arithmetic; Lifetime prediction; Reliability; Invariant Integer Division; reconfigurable architecture","en","master thesis","","","","","","","","2024-02-07","","","","Computer Engineering","Lifetime Prediction for embedded automotive devices",""
"uuid:72573b61-7cad-4707-adb2-9115a438e31e","http://resolver.tudelft.nl/uuid:72573b61-7cad-4707-adb2-9115a438e31e","Microphysical Retrievals in Mixed-Phase Clouds with low LWP using Cloud Radar","Wang, Peiyuan (TU Delft Civil Engineering & Geosciences; TU Delft Geoscience and Remote Sensing)","Unal, C.M.H. (mentor); Dias Neto, J. (graduation committee); Glassmeier, F. (graduation committee); Schleiss, M.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Mixed-phase clouds, which have a significant impact on the global climate, are complex systems where liquid water and various types of ice particles coexist at temperatures below the freezing point. A key process in mixed-phase clouds is riming which alters microphysical and scattering properties of ice particles. Cloud radar is a powerful instrument for observing and understanding the processes that occur within mixed-phase clouds. Observations from multi-frequency radars and simulation results were combined in recent research to retrieve microphysical properties of ice particles in snowfall and ice clouds. This report presents an ambitious attempt to retrieve all common microphysical properties of ice particles, such as maximum dimension, density, aspect ratio and number concentration in slight rime condition using Doppler spectra. Two mixed-phase cloud events with low liquid water path are studied for such purpose. Spectral dual-wavelength ratio is introduced to retrieve maximum dimension of particles. An iteration process is developed in order to retrieve aspect ratio and density of ice particles from observation of spectral differential reflectivity. The number concentration of particles is retrieved with additional spectral reflectivity. With all the retrieved microphysical properties, ice water content and particle size distribution can be further derived. Ice water content is compared with results from an empirical model. The retrieved properties obtained from using three distinct mass-size relations are compared. Also the bulk and spectral retrieved profiles are compared. The retrieval process can provide consistent microphysical properties of ice particles. It is found that the retrieved ice water content is generally smaller than that from empirical model. Besides, the mass-size relation has significant impact on all retrieved microphysical properties except maximum dimension. The resulting profiles from bulk retrieval are smoother, while spectral retrieval can provide values in regions where the former cannot. The possible error from different sources are discussed or estimated, including the effect on dual-wavelength ratio from the elevation angle of radar, the neglect of differential attenuation caused by liquid and the usage of soft spheroid model. Recommendations are discussed, which include the usage of the latest microphysical models for ice aggregates and Discrete Dipole Approximation for electromagnetic wave scattering simulation.","Cloud radar observations; Mixed-phased cloud; Dual-wavelength ratio; Microphysical cloud properties","en","master thesis","","","","","","","","","","","","Geoscience and Remote Sensing","",""
"uuid:0304a61b-14df-44a5-8a72-84b5ea5d1eb6","http://resolver.tudelft.nl/uuid:0304a61b-14df-44a5-8a72-84b5ea5d1eb6","Optimised Private Set Intersection for Vertical Federated Tree Models","Li, Martin (TU Delft Electrical Engineering, Mathematics and Computer Science)","Hai, R. (mentor); Zhan, D. (mentor); Lofi, C. (mentor); Decouchant, Jérémie (graduation committee); Delft University of Technology (degree granting institution)","2024","In recent years, the rapid advancements in big data, machine learning, and artificial intelligence have led to a corresponding rise in privacy concerns. One of the solutions to address these concerns is federated learning. In this thesis, we will look at the setting of vertical federated learning based on tree models. We have built a system that can do both entity resolution through private set intersection (PSI) and vertical federated learning (VFL). In this system, we have implemented an optimisation to pre-sort the data per feature before the start of VFL. We have also created a privacy framework, where we define four levels of privacy. This optimisation did not affect the privacy level of the system. In our results, we have seen that pre-sorting the data lowers the overall training time. How much depends on the number of entities and features of the passive party. We observe from our results that we estimate the speed-up to be 0.3654 seconds per feature and 0.2093 seconds per 1000 entities.","Vertical Federated Learning; Private Set Intersection; Privacy","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:27a06549-10eb-40c6-ae78-38a898241194","http://resolver.tudelft.nl/uuid:27a06549-10eb-40c6-ae78-38a898241194","Well-being Indicators for Car-Free Policies: A study into the selection and operationalisation of well-being indicators for representing local stakeholder interests in the ex-ante evaluation of car-free policies","Verbeeke, Ruben (TU Delft Civil Engineering & Geosciences; TU Delft Transport and Planning; TU Delft Integral Design & Management)","Bosch-Rekveldt, M.G.C. (mentor); Snelder, M. (mentor); Lim, Y. (graduation committee); Pel, A.J. (graduation committee); Heezen, M.J.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","Governments worldwide are planning car-free policies to increase the livability of cities. However, car-free policies often face opposition from local stakeholders, and policy-makers often lack relevant model indicators to represent all stakeholder interests in their ex-ante car-free policy evaluations. Well-being (Dutch: Brede Welvaart) indicators can be more relevant for the various stakeholder interests in car-free policies by covering aspects in the domains of living environment, accessibility, safety and health. This thesis investigates how relevant well-being indicators can be selected and operationalised for the ex-ante evaluation of car-free policies. A well-being indicator selection process was developed and applied to a case study in the Oude Westen neighbourhood in Rotterdam. This process involved conducting thirteen semi-structured stakeholder interviews. The resulting stakeholder interests were analysed to determine the relevant aspects of well-being and the relevant indicators for these aspects. From the shortlist of relevant indicators, three indicators were selected and operationalised in this thesis. At last, two validation interviews were conducted to validate the results of this case study and the developed indicator selection process.
The most relevant stakeholders - municipality, local residents, and local business owners - were selected to be involved in the well-being indicator selection process in the case study. Based on their interests, the most relevant aspects of well-being were found to be the use of space, accessibility of mobility options, accessibility of activities, traffic safety, and noise pollution. This resulted in the operationalisation of three indicators: the use of space for car parking, the number of mobility options, and the traffic mix safety warning.
While the small sample size does not allow for generalisation of the case study results, the results of this thesis do show that the well-being indicator selection process can yield relevant indicators of well-being and that this process can be applied in practice. The operationalised indicators can be relevant to represent stakeholder interests in car-free policy evaluation and can be applied to other cases as well. However, the relevance of the indicators does depend on the type of policy and the stage of the planning process. Using well-being indicators in policy evaluation can enhance the relatability of the evaluation results for stakeholders and potentially increase stakeholder support for policies.","Well-being; car-free; indicators; Policy Evaluation","en","master thesis","","","","","","Double degree in Civil Engineering - Transport & Planning and Construction Management and Engineering","","","","","","Civil Engineering | Transport and Planning","",""
"uuid:96225f95-67da-4576-94b2-af409f9ea628","http://resolver.tudelft.nl/uuid:96225f95-67da-4576-94b2-af409f9ea628","Predicting Vessel Motions: A Comparative Analysis of Machine Learning and Conventional Approaches","Oosterholt, Torsten (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Engineering Structures)","Wang, H. (mentor); Metrikine, A. (graduation committee); Peters, Onno (graduation committee); Jacobs, Peter (mentor); Delft University of Technology (degree granting institution)","2024","Founded in 1910, Boskalis, a leader in offshore operations, contends with limitations in ABB's Ability Marine Advisory System 'OCTOPUS' in predicting maximum vessel motions for heavy-transport vessels (HTVs). Accurate prediction of these motions, especially roll and pitch, is vital for transporting large, heavy structures, as exceeding predefined limits can jeopardize both vessel and cargo integrity. OCTOPUS's challenges, stemming not only from its reliance on linear theory but also potentially from the quality of its environmental data, underline the need for exploring alternatives, such as Machine Learning (ML) approaches, adept at handling complex, nonlinear phenomena, to ensure operational safety and efficiency.
This thesis presents the development and comparison of three new approaches to predict maximum roll and pitch motions. The approaches are compared and evaluated against OCTOPUS. Two validation strategies are used to test their performance under known and unknown loading conditions (LCs). Known LCs in this context refer to the evaluation of data that incorporate LCs that are included in the training dataset for ML-based approaches. On the other hand, unknown LCs refer to the evaluation of data that incorporate LCs that are not included in the training dataset for ML-based approaches. The approaches are trained and validated using sensor data, LC data, and environmental data from 24 different voyages for a specific HTV. They differ in their design and the type of environmental data they use.
The superior performance of ML-based approaches over OCTOPUS in known LCs is mainly due to two factors. First, ML approaches inherently incorporate nonlinear phenomena, which is particularly effective in accurately predicting maximum roll motion. Second, they are better equipped to handle flaws in environmental data. Although these advantages contribute to a significantly lower mean absolute percentage error (MAPE) compared to OCTOPUS, ML-based approaches face challenges in unknown LCs and extreme motion response scenarios. However, it is noteworthy that ML approaches quickly adapt to unknown LCs when small portions of these LCs are included in the training dataset.
ML shows potential in vessel motion prediction, and this thesis underscores the importance of diverse training data to enhance its reliability in unknown LCs and extreme motion response scenarios. For Boskalis, addressing these challenges with strategies such as adjusting the custom loss function, data augmentation, and implementing ensemble methods could improve the accuracy of these approaches. This progress is significant for Boskalis and the wider maritime industry, paving the way for adaptive and efficient prediction systems. Collaborative efforts between industry and academia, using rich data and expertise, are essential to drive these innovations.","Machine Learning; Vessel motions; Prediction","en","master thesis","","","","","","","","","","","","Offshore and Dredging Engineering","",""
"uuid:8d1f9e1f-c279-48f6-8649-6249bd3f00cb","http://resolver.tudelft.nl/uuid:8d1f9e1f-c279-48f6-8649-6249bd3f00cb","Electromagnetic exploration inputs for the geotechnical schematization of dikes","Chavez Olalla, J.F. (TU Delft Geo-engineering)","Heimovaara, T.J. (copromotor); Ghose, R. (promotor); Ngan-Tillard, D.J.M. (copromotor); Delft University of Technology (degree granting institution)","2024","This thesis addresses the application of electromagnetic exploration techniques to reduce uncertainties in the subsurface, particularly in low-lying coastal and delta areas like the Netherlands that are increasingly vulnerable to flooding due to climate change. In response to climate change, countries must reinforce their water defenses, a challenging and costly effort that necessitates efficient resource allocation.
The research focuses on magnetic-dipole electromagnetic induction (EMI) and direct-current electrical resistivity tomography (ERT) due to their sensitivity to the electrical resistivity of the subsurface, which correlates with other geotechnical properties. Both methods are easily deployable and can cover large areas relatively quickly.
Chapter 2 delves into the theoretical aspects of EM data acquisition in dikes, demonstrating that EMI devices with far-offset receivers can capture large anomalies at a much faster rate than ERT. However, both methods perform poorly in detecting small, detrimental features such as thin layers, and are affected by groundwater salinity.
Chapter 3 proposes a method to estimate the geometric variability of soil layers using geophysical tomograms. EMI and ERT tomograms are employed to estimate the orientations of soil layers, enabling an accurate estimation of geometric variability with reduced exploration effort.
Chapter 4 highlights the value of high-resolution ERT in estimating the spatial variability of properties within homogeneous soil units. This method serves as an efficient alternative for estimating internal variability in geotechnical analyses of water defense structures and other geotechnical infrastructure.
An essential contribution of this thesis is the proposal of quantitative and reproducible methods for characterizing subsurface heterogeneity in the context of water defenses. These insights help reduce uncertainties and optimize resource allocation for dike reinforcement. The integration of geophysical methods with other geotechnical site data enhances the understanding of the subsurface. Chapter 5 summarizes the main findings of this research regarding the geotechnical schematization of dikes.","Geophysics; Geostatistics; Heterogeneity; Dikes","en","doctoral thesis","","","","","","","","","","","Geo-engineering","","",""
"uuid:6a96db15-bdb1-4ae8-81be-db828a8388fd","http://resolver.tudelft.nl/uuid:6a96db15-bdb1-4ae8-81be-db828a8388fd","Deactivation Mechanisms and timescales of nickel electrodes in alkaline water electrolysis","Vijverberg, Lotte (TU Delft Applied Sciences; TU Delft Process and Energy)","Haverkort, J.W. (mentor); Vermaas, D.A. (graduation committee); Kortlever, R. (graduation committee); Delft University of Technology (degree granting institution)","2024","Alkaline water electrolysis emerges as a promising technology for green hydrogen production, playing a significant role in global decarbonization. Nickel-based electrodes are widely used in alkaline water electrolysis due to their excellent catalytic properties for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). However, nickel electrodes often experience a decrease in activity over time. Attempts of existing literature to investigate nickel deactivation employ conditions that differ from industry standards. Therefore, a more profound understanding of these phenomena under industry-relevant conditions is crucial for averting specific degradation pathways in future electrode design. This thesis investigates the deactivation phenomena and the timescales of untreated nickel electrodes during the OER and HER at 323 K and 30 wt% KOH, employing a current density of 1 A cm-2. The electrolyte concentration and current density match industry standards, and the temperature aligns more with industrial practices than literature. The OER overpotential increases under these conditions in 2.5 hours by 0.19 V and still increases after this period. The HER overpotential increases by 0.65 V and stabilizes after 20 minutes. Electrochemical and surface analytical tests suggest that both reactions primarily deactivate due to a redox reaction.","AWE; Nickel; Deactivation","en","master thesis","","","","","","","","","","","","Chemical Engineering","",""
"uuid:c0759959-d7ff-47d9-ab33-63f7f64ac8ee","http://resolver.tudelft.nl/uuid:c0759959-d7ff-47d9-ab33-63f7f64ac8ee","The Effect Of Wall Heating On Stability And Laminar Breakdown Of Three-Dimensional Boundary Layers: An Experimental Study","van de Weijer, Tim (TU Delft Aerospace Engineering)","Kotsonis, M. (mentor); Barahona Lopez, M. (mentor); Rius Vidales, A.F. (mentor); van Oudheusden, B.W. (mentor); Delft University of Technology (degree granting institution)","2024","An important challenge in the electrification of aircraft propulsion systems is the design of thermal management systems because of an increased heat load that needs to be dissipated. As an alternative to high-drag external heat exchangers, one can consider surface heat exchangers to dissipate the extra thermal energy. This reduces the size of the external heat exchangers and consequently reduces drag. However, a non-adiabatic wall can affect skin friction through a movement of boundary layer transition. Limited studies are available on the effect of non-adiabatic surfaces on laminar-to-turbulent transition in swept wing boundary layers dominated by crossflow instability (CFI). Therefore, the current work experimentally investigates the effect of surface heating on the stability and breakdown of the stationary crossflow instability. The experimental work is supported by Compressible Linear Stability Theory (CLST) computations.
Hot-Wire Anemometry (HWA) and Cold-Wire Anemometry (CWA) measurements of the boundary layer are performed on the STEP model, which features a 45 degree swept flat plate, for both adiabatic and heated surface conditions. Both the experimental and CLST results show a destabilisation of the primary instability linked to the increase in the growth rate of the stationary crossflow (CF) mode. The experimental results show that the type-I secondary CF instability exhibits a larger magnitude in the presence of wall heating and the mode emerges upstream compared to the adiabatic wall condition. The type-III mode displays a significant increase in magnitude in the presence of wall heating, thereby indicating a considerable destabilisation. The effect on laminar breakdown is identified by analysing velocity fluctuations in the 12-17 kHz frequency band in planes parallel to the surface for two different wall distances. A temperature ratio of 1.035 is found to advance breakdown by 5.7%.","Wall heating; Crossflow instability; Hot wire anemometry; Cold wire anemometry","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:bf7dbb7e-63a6-4a28-9964-78b555c54445","http://resolver.tudelft.nl/uuid:bf7dbb7e-63a6-4a28-9964-78b555c54445","Fortress Without Barriers: Maintaining Accessibility in the Face of Security","Fajtl, Michael (TU Delft Architecture and the Built Environment)","van Zalingen, J.M. (mentor); Eckardt, H.F. (mentor); Söylev, Y. (mentor); Overschie, M.G.F. (graduation committee); Delft University of Technology (degree granting institution)","2024","In an era when rising threats put increasing pressure on security demands in state office buildings, the public trust in these same governmental institutions is on the decline, owing to a sense of detachment and lack of transparency.
This detachment partially stems from the functional and physical separation of people’s civic and political lives, leaving public officials as uncountable, a separated class unresponsive to the everyday people, who in turn can glance little of the everyday working of their government.
In other words: it is easier to pass unfavourable legislation when you never interact with the common people and sit in your fortress hidden from protests. For these reasons, the future must see the creation of new governmental spaces that are public in nature, but also safeguarded from new dynamic threads. New design approaches in established typologies need to be sought to answer these relationship questions that stem from new state, societal, and technological developments.
The Graduation Project ‘Fortress Without Barriers‘ seek to explore these issues of security and accessibility by using a scenario involving the design of a new Federal Ministry of Defence headquarters in Berlin. At first glance this typology might be perceived as ill suited to the integration of public life, even agitative. But rather the project places it as the ultimate test for whether these values can be effectively expressed in an urban context. Defence Ministry being the most prime domain of security, on the scale of city within a city, and placing the most private and secured programme imaginable alongside the proposed public functions.
“In what way does reducing embodied carbon in residential building projects impact the investment decision-making process from an investor's perspective?”
To explore this, the study first conducts a literature review and exploratory interviews, followed by three case studies with semi-structured interviews. The findings reveals that the integration of embodied carbon in the investment decision-making process is still in its early stages. Although there is growing awareness and interest, embodied carbon is not yet a standard consideration in investment decisions. This integration depends on the flexibility of investors and the specific sustainability goals of projects. Traditional financial models and evaluation methods have largely remained unchanged. The study concludes that there is a need for further standardization and integration of carbon reduction in all aspects of investment practices to encourage the construction sector to achieve the goal of carbon net-zero by 2050.
The second problem where we research this difference is the Big-Line-Big-Clique Conjecture. As far as we know, this conjecture has not been studied yet in other dimensions than the plane.
Apart from discussing the relevant literature for both problems, we present a formulation of the Big-Line-Big-Clique Conjecture in higher dimensions and a generalisation in terms of (hyper)graphs. We also state a stronger version of the conjecture that would imply the BLBC Conjecture to be true. However, we show a counterexample to the stronger conjecture, leaving the original one open.
Factored representations involve variables describing various features of the environment. These variables, along with their possible values, define the agent’s states. Unlike standard representations, factored representations provide a unique perspective that enables us to gain deeper insights into the underlying structure of the environment and refine our understanding of the problem at hand.
By analyzing variable dependencies, we can abstract simplified representations of the environment states and construct computationally lightweight models. To do so, we will explore potential factorizations of key functions governing the reinforcement learning problem, such as transitions, rewards, policies, or value functions. These factorizations can be achieved by exploiting variable redundancies and leveraging relations of conditional independence.
This thesis proposes a set of methods that are shown to improve the efficiency and scalability of reinforcement learning in complex scenarios. We hope that the findings of this research contribute to showcasing the potential of factored representations and serve as inspiration for future research in this direction.
Accurately representing post-buckling behaviour in finite element models requires accounting for geometric and loading imperfections. The present study explores their effects on the post-buckling behaviour of a composite L-stiffened panel. A finite element model is created and validated based on an experimental case. This is then further modified to incorporate imperfections. Geometric imperfections are modelled using linear eigenvalue modes, while loading imperfections are introduced via a rigid loading plate making contact at an angle.
The research showed that both first and higher eigenmode combinations for geometric imperfections influence post-buckling behaviour. Their shape and amplitude impact the transition into post-buckling and their ultimate loads. Similar behaviour was also observed for loading imperfections. Additionally, their configuration also showed an offset in axial displacement results. These insights emphasise the need for precise imperfection modelling to promote safer and more efficient post-buckling design of aerospace structures.","Post-buckling analysis; Composites; Stiffened panel; Abaqus; FEM analysis; Geometrical Imperfections; Loading Imperfections","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:1553d8c9-79df-44dd-8c9f-d2eb9f7017b8","http://resolver.tudelft.nl/uuid:1553d8c9-79df-44dd-8c9f-d2eb9f7017b8","Uncertainty-Aware Reinforcement Learning for Flight Control: Mastering the Mystery of Flight","Homola, Marek (TU Delft Aerospace Engineering)","van Kampen, E. (mentor); Li, Y. (mentor); Delft University of Technology (degree granting institution)","2024","In the rapidly evolving aviation sector, the quest for safer and more efficient flight operations has historically relied on traditional Automatic Flight Control Systems (AFCS) based on high-fidelity models. However, such models not only incur high development costs but also struggle to adapt to new, complex aircraft designs and unexpected operational conditions. As an alternative, deep Reinforcement Learning (RL) has emerged as a promising solution for model-free, adaptive flight control. Yet, RL-based approaches pose significant challenges in terms of sample efficiency and safety assurance. Addressing these gaps, this paper introduces Returns Uncertainty-Navigated Distributional Soft Actor-Critic (RUN-DSAC). Designed to enhance the learning efficiency, adaptability, and safety of flight control systems, RUN-DSAC leverages the rich uncertainty information inherent in the returns distribution to refine the decision-making process. When applied to the attitude tracking task on a high-fidelity non-linear fixed-wing aircraft model, RUN-DSAC demonstrates superior performance in learning efficiency, adaptability to varied and unforeseen flight scenarios, and robustness in fault tolerance that outperforms the current state-of-the-art SAC and DSAC algorithms.","Autonomous Flight Control; Deep Distributional Reinforcement Learning; Uncertainty-Driven Control; Safety-Critical Systems; Sample Efficient Machine Learning; Reinforcement Learning; Autonomous System","en","master thesis","","","","","","Public code repository: https://github.com/mhomola/RUN-DSAC","","","","","","Aerospace Engineering","",""
"uuid:f82420e1-eecb-4ae2-81b4-7b86c6b91b13","http://resolver.tudelft.nl/uuid:f82420e1-eecb-4ae2-81b4-7b86c6b91b13","Integrating Blockchain Technology with Project Management System in the AEC Sector","YU, HAIHAN (TU Delft Civil Engineering & Geosciences)","Papadonikolaki, E. (mentor); Hall, Daniel M. (graduation committee); Decouchant, Jérémie (graduation committee); Schipper, H.R. (graduation committee); Delft University of Technology (degree granting institution)","2024","Since its emergence in 2008, blockchain technology has significantly expanded its scope, impacting various industries beyond its initial cryptocurrency applications. Its potential to enhance established practices is increasingly recognized, yet its application in the Architecture, Engineering, and Construction (AEC) industry has been relatively little researched to date, let alone been applied in practice. This research aims to develop a system facilitating the initiation and management of architectural projects on the blockchain, enabling multi-disciplinary collaboration and participation, by integrating blockchain technology into the AEC ecosystem. The proposed system is designed to allow architects, engineers, and designers, irrespective of their preferred design software, to contribute, manage and record their designs. By uploading these designs to the InterPlanetary File System (IPFS) and recording the IPFS hashes on the Ethereum blockchain, the system ensures immutable data provenance, transparent ownership representation, and heightened project transparency. Furthermore, this framework automates various aspects of project management, including contractual obligations, payments, and compliance verification through smart contracts. At the core of this research is a multi-step approach that begins with a literature review to establish the current state of blockchain applications within the AEC sector. The review focuses particularly on the potential of smart contracts, NFTs, and IPFS for improving the management of construction projects. A conceptual framework is then developed, drawing from the literature to designing a prototype system that integrates these technologies. The prototyping phase involves creating a blockchain-based system where architectural project management can be conducted securely and efficiently. Key to this phase is the crafting of smart contracts to automate project workflows and the use of NFTs for clear delineation of design ownership and achievements. The system also incorporates a method for offchain storage of design files through IPFS, connected to the blockchain, ensuring data integrity and easy retrieval. Systematic testing under certain scenario assesses performance and informs iterative optimization to refine the system's functionality. A performance evaluation strategy is employed to assess the prototype, ensuring its suitability for real-world applications in the AEC sector. This research develops a blockchain-based system in attempt to restructure project management in the AEC sector. Through iterative development, testing, and optimization, the objective of this study is to contribute to enhanced efficiency, transparency, and collaboration within the industry, exploring the potential benefits of integrating blockchain technology in a structured and measured manner.","Blockchain Technology; Blockchain; NFT; IPFS; Smart Contract; Construction Management; AEC industry","en","master thesis","","","","","","","","","","","","Civil Engineering | Building Engineering","",""
"uuid:2f1719da-336e-47c2-b1e4-9e4b60773bde","http://resolver.tudelft.nl/uuid:2f1719da-336e-47c2-b1e4-9e4b60773bde","Overcoming Network Saturation in Continual Learning: A Method for Dynamic Parameter Adjustment","Qin, Xusen (TU Delft Mechanical, Maritime and Materials Engineering)","Bessa, M.A. (mentor); Sluiter, M.H.F. (mentor); Delft University of Technology (degree granting institution)","2024","Neural networks have made significant progress in domains like image recognition and natural language processing. However, they encounter the challenge of catastrophic forgetting in continual learning tasks, where they sequentially learn from distinct datasets. Learning a new task can lead to forgetting important information from previous tasks, resulting in decreased performance on those earlier tasks. This issue is further intensified in dynamic scenarios where the task sequence varies unpredictably. To address this problem, architectural methods have been developed to modify a neural network's structure, creating or adapting subnetworks to retain task-specific knowledge and mitigate catastrophic forgetting. However, these solutions can lead to network saturation, where the accumulation of task-specific adaptations hampers the network's ability to learn new tasks. This research aims to address the problem of network saturation by developing innovative methods that enable neural networks to maintain high performance across both existing and new tasks in continual learning scenarios. Eventually, the new model improved its learning ability on new tasks in the presence of an allowable forgetting, while demonstrating better overall learning ability.","Deep Learning; Continual Learning; Network Saturation; Image recognition; Data-Driven Analysis","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:098192cd-0d56-4536-9596-6aab771ace09","http://resolver.tudelft.nl/uuid:098192cd-0d56-4536-9596-6aab771ace09","Timber on Top: A Parametric Exploration of Vertical Extension Potential in the Rotterdamse Laag","Kwakman, Rik (TU Delft Civil Engineering & Geosciences)","Louter, P.C. (mentor); Schuurman, A.C.B. (mentor); Felicita, M.P. (mentor); Bresser, Djonno (mentor); Delft University of Technology (degree granting institution)","2024","The Netherlands is grappling with a substantial housing crisis, marked by an estimated shortage of 380,000 houses. To address this issue, an annual creation of 100,000 new housing units is deemed necessary. However, the current construction rate stands at only 70,000 houses per year, indicating a considerable gap in resolving the housing crisis. Recognizing the potential of urban densification, especially through vertical extension using Cross-Laminated Timber (CLT), presents a sustainable solution. Nevertheless, challenges arise, such as the unique approach to vertical extension and the structural constraints posed by CLT's lower strength compared to materials like concrete.
This research aims to identify the vertical extension potential of CLT in existing buildings by developing a parametric tool that considers various structural constraints. The ultimate goal is to contribute to informed decision-making practices for sustainable and effective structural design in vertical extensions.
The methodology comprises four phases: analysis, synthesis, simulation, and evaluation. The analysis phase examines existing vertical extensions, structural context, and spare capacity concepts, forming the basis for synthesis. A parametric tool is then created using Grasshopper and Karamba, employed in the simulation phase to conduct a parameter study based on the analysis phase findings. This study assesses the effects of the original structure's base geometry on spare capacity and evaluates the design of the extension itself.
The results of the parameter study reveal that the presence and placement of a stability core have the most significant impact on spare capacity in the existing building. The original construction grid and building height also influence spare capacity, though to a lesser extent. Additionally, wall layouts in the extension, such as core alignment, functional design, and façade-aligned layouts, significantly affect spare capacity utilization in both the original structure and the extension.
Variations in extension grid show differences in spare capacity utilization, with effects smaller in magnitude compared to wall layout variations and displaying less dependence on the original structure's geometry. In the vertical extension itself, failure tends to concentrate on connections between CLT panels and floors, particularly with wall layouts emphasizing functional design.
In conclusion, the research, coupled with the development of a parametric tool, successfully achieves its main goal. The tool's accuracy is validated through extensive assessments of horizontal load transfer from the extension to the original structure. The parameter study highlights the significant effects of various parameters on extension design and the original structure, emphasizing the tool's utility in exploratory design stages for vertical extensions.","vertical extension; CLT; timber; Rotterdamse Laag; parametric modelling; parametric tool","en","master thesis","","","","","","","","","","","","Civil Engineering | Building Engineering - Structural Design","",""
"uuid:ce6b5165-2f5a-4ae7-8966-16b194459364","http://resolver.tudelft.nl/uuid:ce6b5165-2f5a-4ae7-8966-16b194459364","Immersive Spatial Experience: The development of a novel assistive technology for dynamic spatial environment perception for the visually impaired","Mispelblom Beijer, Juerd (TU Delft Industrial Design Engineering)","Rozendaal, M.C. (mentor); Schermer, W. (graduation committee); Delft University of Technology (degree granting institution)","2024","This project develops a novel assistive technology for aiding in mobility of the Visually Impaired in collaboration with Royal Visio. This technology provides VIPs with a dynamic tactile map of their environment to improve spatial awareness. The aim is to improve overview, wayfinding and orientation, while also improving the overall mobility experience by boosting confidence and independence through comprehensive awareness of the environment.
The initial research phase seeked to understand the needs and challenges in mobility faced by VIPs, both from a functional point of view, focusing on wayfinding and orientation, and on a psychosocial level, focusing on emotional and experiential needs that derive from the process. It was found that the absence of the visual sense significantly limits VIPs’ ability to overview and comprehend their surroundings, hindering their orientation and use of distant environmental reference for movement, resulting in the reliance on physical guidelines. Reduced awareness of potential hazards and complicated wayfinding often leads focus the functional aspects of mobility. They experience a vigilant, alert state of mind, focusing mainly on avoiding risks and not losing their way. This intense focus diminishes engagement with the broader environment and leads VIPs to stick to familiar areas. Such limitations impact their independence but also their connection with society.
The review of current assistive solutions reveals that they primarily concentrate on similar functional aspects of mobility, using interface technologies that fall short in significantly enhancing environmental awareness and reducing the perceived lack of environmental awareness.
This gap highlights the need for assistive technologies that focus not only on wayfinding and navigation but also on these experiential aspects. The project proposes a multidimensional, spatial interface technology akin to conventional tactile maps but of dynamic nature, is capable of real-time updates based on the actual environment, moves along with the user and subsequently is able to display non-static and small-scale environmental elements. This dynamic tactile map aims to provide a deeper sense of environmental awareness and understanding.
In the subsequent research-through-design phase, a prototype of the conceptual product, that provides a dynamic top-view map of the environment on an electronic braille screen, is put to the test. Despite highlighting the potential of this conceptual direction for spatial understanding, orientation and free, confident movement, the experiment reveals significant requirements for improvement of the interface and environmental mapping technologies.
The final design, “Immersive Spatial Awareness,” features an improved interface with in the form of a haptic augmented reality system that enables a dynamic 360° 3D perception of the environment, primarily through touch, but supplemented with multisensory elements. While significant technological development and Human-Centred-Design is required to realise this visionary concept, the applied technologies are grounded in actual research and existing technologies that see rapid development, highlighting the realistic potential of the concept. The design is supplemented with a roadmap that details and presents the development process towards the successful application of this technology.","Visually Impaired; Object with Intent; Inclusive Design; Research-by-design","en","master thesis","","","","","","Double degree in Integrated Product Design and Design For Interaction","","","","","","Integrated Product Design","",""
"uuid:a73afc38-214a-4ed7-ad14-575ecfc3f30f","http://resolver.tudelft.nl/uuid:a73afc38-214a-4ed7-ad14-575ecfc3f30f","Practical guidelines towards a circular-adaptable reuse of vacant and obsolete real estate: A particular reference to the Dutch context","Amrani, Khalil (TU Delft Architecture and the Built Environment)","Wamelink, J.W.F. (mentor); Hamida, M.B. (graduation committee); Delft University of Technology (degree granting institution)","2024","The circular economy is an economic model in which resources are circulated in a closed loop by adopting the R-strategies (e.g. reuse, recycling, and reduce) to minimize waste and pollution. Repurposing vacant buildings, known as adaptive reuse, is in line with the principle of circular economy, as it contributes to the reuse of the built assets instead of their demolition. In addition, this can help to conserve resources and reduce the environmental impact of building construction. Furthermore, adaptive reuse is not only necessary for vacant properties but also for obsolete buildings. Thus, it is an unavoidable practice in the built environment. This implies that adaptability should be incorporated into this kind of projects besides circularity. However, recent research revealed that many of the Dutch adaptive reuse projects were implemented without adequate consideration of circular solutions.
Accordingly, this research project aims to develop practical guidelines that could guide practitioners on operationalizing circularity and adaptability in the adaptive reuse of vacant and obsolete real estate.
Sequentially, three approaches with different research methods were followed to answer the main research question: ‘’How can circularity and adaptability be promoted in the reuse of vacant and obsolete real estate?’’
The first approach is the documentation of existing knowledge. This approach was followed to answer the first sub-question: ‘’What are the criteria and measures for reusing obsolete and vacant buildings in a circular and adaptable manner?’’ In this approach, a literature review was carried out. The literature review led to the identification of 12 criteria and 8 measures for circular and adaptable adaptive reuse.
The second approach is case studies on circular adaptive reuse projects of vacant and obsolete buildings. This approach was followed to answer the second sub-question: ‘’To what extent are circularity- and adaptability-related measures implemented in reusing vacant and obsolete buildings?’’ In this approach, three research methods were used in two case studies, namely: archival research, interviews, and field observation were used simultaneously. The findings of the cross-case analysis of two case studies resulted in adding 8 measures to the previously defined measures from the literature, totaling 16 measures.
The third approach is the formulation and validation of guidelines based on knowledge gained from theory and practice. This approach was followed to answer the third sub-question: ‘’How can guidelines guide professionals on how to promote circularity and adaptability-related measures in the reuse of vacant and obsolete buildings?’.’ In this approach, the guidelines were synthesized based on knowledge gained from the literature and findings of the two case studies. The results of developing and validating the guidelines contributed to adopting 13 guidelines. Overall, the validation outcomes indicate that the guidelines are informative and useful when visualized. However, they need to be updated constantly for their applicability in practice.","Adaptive reuse; Adaptability; Circular Economy (CE); Guidelines; Vacancy; Obsolescence; Real Estate; Circular building adaptability","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:0d4f6592-456a-413a-a10b-e7d30930e126","http://resolver.tudelft.nl/uuid:0d4f6592-456a-413a-a10b-e7d30930e126","Analysis of the visibility of GPS satellites in the urban environment using point cloud representation","Gheorghiu, Irina (TU Delft Architecture and the Built Environment)","Verbree, E. (mentor); Meijers, B.M. (graduation committee); Hoogenboom, J.J.J.G. (graduation committee); Delft University of Technology (degree granting institution)","2024","Global Navigation Satellite System is a spatial data acquisition technique, mostly used in navigation and positioning. One of the main components of this technique is the satellite visibility, which refers to the connection between the satellite and the ground receiver. It is known that the GNSS positioning systems are not as performing in urban areas due to the dense coverage of obstacles (buildings, trees, high terrain etc.). These obstacles can obstruct and reflect the lines of sight between the satellite and the ground receiver which can affect the quality of the performance of the GNSS service. The geometry configuration of the satellites above the receiver is another important aspect that has to be taken into consideration.
This research focuses on implementing a simulation similar to that of GNSS mission planning tools, but using point cloud data as the 3D representation of the surroundings of the receiver and using only the GPS constellation of satellites. Due to the large size of a point cloud sample, two visibility algorithms have been implemented to filter the necessary 3D data. The main output of the simulation are the dilution of precision values which give further information about the satellites' positions. The main purpose of this research is to understand the dilution of precision values, which are directly related to the geometry of the satellite configuration above the receiver. Understanding the behaviour and how the receiver's environment influences the DoP values can result in leading GNSS surveying missions with better results.
This output is then compared with the data acquired from a GNSS receiver in a real scenario. While the results are not favorable for the implemented simulation, it gives a better understanding of the surroundings of the receiver's location by using point cloud data than the already existing online GNSS tools.","Satellite; Constellation; GPS; GNSS; Land surveying; Point Cloud; Visibility; Analysis; Urban environment; LiDAR","en","master thesis","","","","","","","","","","","","Geomatics","","51.993889, 4.378264"
"uuid:e4870113-975f-4fa1-96dd-1e6d0f061e29","http://resolver.tudelft.nl/uuid:e4870113-975f-4fa1-96dd-1e6d0f061e29","Time-window based Truck Appointment System with Adaptive Slot management and Real-Time Truck Information: A case study for the loading operations in a Chemical Plant","Skoulas, Vasileios (TU Delft Civil Engineering & Geosciences)","Tavasszy, Lorant (graduation committee); van Duin, Ron (mentor); Duinkerken, M.B. (mentor); Vanga, R. (mentor); Delft University of Technology (degree granting institution)","2024","Long truck queues and congestion around terminals is a common sight, however they come with many negative externalities for all the stakeholders involved. Truck Appointment System (TAS) is the most commonly used system to face these problems, but it still has some drawbacks and limitations. Consequently, in this research an extension of the typical TAS is proposed in order to improve its performance. The main components of this system are the use of truck dependent time-windows, the utilization of real-time information and the adaptive trucks rescheduling model. The duration of the arrival time-windows is longer than the actual service times, allowing overlap between time-windows. Thus, the actual service sequence might be different from the reserved one. To determine the actual loading sequence an Optimization model is developed, which is run periodically while utilizing real-time truck information. A chemical plant is used as a case study in this research. The performance of the proposed TAS is assessed with the use of a Simulation model. The outcomes of this research suggest that the a less strict TAS can significantly improve the system’s performance, especially trucks’ waiting times. Also, the system’s resilience against disruptions and the plant’s environmental footprint are improved, while queues are reduced.","Truck Appointment System (TAS); Truck Arrival Management System; Time-window; ETA; Real-time Information; Rescheduling; Slot Management; Chemical plant; Optimization model; Mixed Integer Linear Programming (MILP); Simulation model","en","master thesis","","","","","","","","","","","","Transport, Infrastructure and Logistics","",""
"uuid:620f1e36-48bd-4f35-b543-ff52a4fa0d39","http://resolver.tudelft.nl/uuid:620f1e36-48bd-4f35-b543-ff52a4fa0d39","Salt Intrusion Modelling via the Particle-tracking Framework","Lin, Sicong (TU Delft Electrical Engineering, Mathematics and Computer Science)","Verlaan, M. (mentor); Vuik, Cornelis (graduation committee); Delft University of Technology (degree granting institution)","2024","The topic of this thesis project is to use the particle-tracking framework to study salt intrusion.
This project was proposed by Deltares and is a small part of the SALTISolutions project, that attempts to build a digital twin model of the Rhine-Meuse Delta. From a mathematical perspective, the particle-tracking framework is inspired by the theoretical connection between partial differential equations that describes substance transport and stochastic differential equations (SDEs). The idea is to use replace the continuous substance distribution in the fluid by many particles. After tracking the particles, the consequent substance distribution can be approximated by the particles' distribution at certain time instant. There are two major achievement of this project. Firstly, different implementation of non-penetrating and flux boundary conditions for the particle-tracking framework are tested and compared. The recursion algorithm is preferred for the previous and the ``Neumann-wise'' is recommended for the latter. Secondly, the convergence order of SDE numerical schemes and their influences on the simulation of the vertical transport physics are examined by studying the one-dimensional pure diffusion test case. We see that most simple Euler scheme contaminates the stratification completely in a theoretical setting even using a small timestep, indicating that it might be worthwhile to switch to high-order schemes whenever possible. However, even if one can implement other higher order numerical scheme correctly and efficiently, which is not easy, it might be equivalently important to have enough particles and good interpolation of velocity and diffusion field in the computation domain, because they may introduces error comparable to the diffusion error. Since salt transport is already resolved by the Delft3D-FM model, it is of nonsense to use the particle-tracking framework to study transport. The one-dimensional pure diffusion test case is mainly used for verification of the method. Actually, the particle-tracking framework should be used in combination of the diagnostics timescales and tracer methods. This often requires calculation of the statistics of the particle ensemble. It will be interesting to conduct such analysis on a realistic three-dimensional test case, and this could be the field of future research.","salinity intrusion; particle-tracking; SDE numerical methods","en","master thesis","","","","","","","","","","","","Applied Mathematics | COSSE (Computer Simulations for Science and Engineering)","",""
"uuid:913c04f8-4157-4842-a7fe-c5368ace4eae","http://resolver.tudelft.nl/uuid:913c04f8-4157-4842-a7fe-c5368ace4eae","Techno-Optimism and its Impact on Civil Servant Decision Making: A Case Study and Insights into AI Case Routing for Welfare Benefits Allocation","de Vries, Bo (TU Delft Technology, Policy and Management)","Dobbe, R.I.J. (mentor); van der Voort, H.G. (graduation committee); Heyning, Nicolaas (mentor); Delft University of Technology (degree granting institution)","2024","In our thesis, we conducted an in-depth exploration of the integration of Artificial Intelligence (AI) in public sector decision-making, focusing particularly on AI case routing for welfare benefits allocation. Initially, our research was guided by a techno-optimistic viewpoint, presuming that municipalities would inherently benefit from AI adoption. However, as our study progressed, we encountered the complexities and challenges inherent in the practical implementation of AI in public services.
We employed the Design Science Research methodology, utilizing a diverse array of methods including literature reviews, case studies, expert interviews, and system safety analysis. Our objective was to develop a method-type artifact to enhance decision-making in civil services, with a special emphasis on the application of AI in welfare benefits allocation. Our findings indicated that AI implementation in the public sector is highly context-dependent, requiring a tailored approach that addresses various technical, organizational, and cultural barriers.
Throughout our research, we identified critical factors such as the need for transparency, fairness, and accountability in AI systems. We recognized the importance of adopting a balanced perspective that considers both AI and non-AI solutions. Our study highlighted the potential benefits of AI in public services, such as increased efficiency and improved quality of decision-making. However, we also noted significant challenges in ensuring system safety and maintaining ethical standards.
Through expert interviews and a detailed system safety analysis, we emphasized the necessity of establishing clear rules for the responsible use of AI case routing and addressing the associated risks. Our research concluded that AI might not always be the most suitable approach, particularly if safety concerns and ethical considerations outweigh the potential benefits.
In summary, our thesis underscores the need for a critical and balanced approach to the integration of AI in public services. We advocate for a holistic strategy that involves collaboration among government, academia, industry, and civil society. This approach is vital to harness the potential benefits of AI while mitigating risks and ensuring the well-being of society.","Artificial Inteligence; Repetitive Civil Servant Decision Making; Implementation; Case Routing","en","master thesis","","","","","","","","","","","","Engineering and Policy Analysis","",""
"uuid:8e012c02-b71b-42bd-93f7-1b76fb31aeea","http://resolver.tudelft.nl/uuid:8e012c02-b71b-42bd-93f7-1b76fb31aeea","A Workers' Enclave","Chen, Dongyan (TU Delft Architecture and the Built Environment)","Milani, S. (mentor); Schoonderbeek, M.G.H. (mentor); Jennen, P.H.M. (mentor); Delft University of Technology (degree granting institution)","2024","This project experiments in representing the spatial complexity of a research area and reintroduces it to an adjacent site in the language of architecture. A heavy industrial district for ship building and maintenance is centered on and taken as a field with its dense configuration of artifacts (cranes, workshops, cargoes) and invisible force activated by movement of these objects. For a group of people – workers who work and live inside everyday in positions of insecure employment, safety and long work hours, a collective place is proposed for leisure and cultural activities.","workers' club","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Borders and Territories","",""
"uuid:c8b7affd-c166-457a-8069-d06fc9649b53","http://resolver.tudelft.nl/uuid:c8b7affd-c166-457a-8069-d06fc9649b53","Reimagining Home: a Qualitative Research on Innovative Flex Housing Partnerships and Subsidies for Empowering Status Holder Integration","van der Horst, Lars (TU Delft Architecture and the Built Environment)","van Bortel, G.A. (mentor); Veldhuis, J.H. (mentor); Brijder, S. (Simon) (mentor); Delft University of Technology (degree granting institution)","2024","The Netherlands is dealing with a severe housing crisis due to factors like population growth and a shortage of affordable homes. This has led to soaring housing prices impacting all citizens. Particularly impacted by the consequences of ineffective policies for housing provision are status holders. Due to lack of homes made available for this target group the throughput of refugees with a temporary residency permit out of reception centres stagnates, increasing the pressure on these already overcrowded settlements.
Urgent action is needed, including comprehensive housing policies and increased investment in affordable housing. Therefore the government has introduced flexible housing as a promising solution. These are modular houses placed on temporary plots otherwise unsuitable for permanent housing.
However, studies show that in order to integrate into society, factors such as housing stability, access to social network and future perspective play an important role. This is seemingly difficult to reconcile with the temporary character of flex homes.
This study examines strategies for stakeholders to develop flex homes in a manner that enhances the capabilities of status holders to integrate. By identifying approaches and practices that can optimize partnerships between key stakeholders from both the social and spatial realm and ways to encourage these partnerships. This can be done with financial arrangements such as subsidies. Through a comprehensive literature review, interviews with experts and a case study of three flex housing projects, the partnerships, financial arrangements and capabilities for integration are investigated.
Findings show that early engagement of key stakeholders, interdisciplinary partnerships and financial arrangements that hold these interdisciplinary collaborations as a condition can have a positive impact on the contributing factors of integration for status holders. Primarily because this allows the social partners to exchange their knowledge on social integration at an early stage in the development process, influencing both the design as the long term social management approaches.
This study suggests that the integration capabilities of status holders should be considered at an early stage in the development process. Requiring a contribution from key stakeholders from both the social domain, as the spatial domain, and stimulating mechanisms from the government.
Keywords:
flex housing, integration, status holders, partnership models, financial arrangements
The research starts with an extensive literature review of existing research on biodiversity in the built environment, establishing a foundational framework for subsequent methods. Interviews with experts are conducted to delineate the identified problem, gaining valuable insights and knowledge from ecologists. This is followed by a focus group workshop with participants from various disciplines, in which a process is designed with biodiversity guidelines and considerations. While the expert interviews focused mainly on the role of the government, the workshop discussions emphasised the role of the project developer, highlighting an observable tension between these stakeholders that necessitates collaborative alignment within the multi-plot context.
Recognising the impact of scale, the research underscores the need for collaborative efforts across multiple plots to enhance urban biodiversity. Biodiversity thrives at broader spatial scales where interconnected networks of green areas can support larger populations and facilitate species movement. Emphasising the importance of stakeholder collaboration, the developed process and implementation framework offer valuable guidance for project developers and other stakeholders. Roles, responsibilities, and priorities of stakeholders vary per urban area development project and biodiversity ambitions, which makes biodiversity enhancement complex. Biodiversity implementation in urban area development projects requires early area analysis, consistent oversight of objectives, seamless integration of biodiversity goals into the overall vision, and continuous monitoring throughout the development process.","biodiversity; urban area development; stakeholder collaboration; sustainability; nature-based solutions; ecosystem services; project developer","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:b1731cd0-e118-4cbd-8200-1cf229030698","http://resolver.tudelft.nl/uuid:b1731cd0-e118-4cbd-8200-1cf229030698","Navigating Risk to Resilience: Examining the impact of water risks on the investment decision-making process in polder-area development projects in the Netherlands","Zantinge, Daniël (TU Delft Architecture and the Built Environment)","Geurts, E.H.M. (mentor); Taylor, Zac (graduation committee); Delft University of Technology (degree granting institution)","2024","In the coming years, the Netherlands is expected to face various climate change-related challenges. Until 2030, the Dutch government has set the goal for the development of nearly a million dwellings (De Jonge, 2022), whereby 600,000 dwellings are being carried out in areas prone to flooding (Deltares, Bosch Slabbers, & Sweco, 2021; Groenemeijer & van der Lelij, 2021). In literature, work has been done regarding the current use of adaptation pathways, policies and their impact on decision-makers and practitioners (Restemeyer, van den Brink, & Woltjer, 2017; van Alphen, Haasnoot, & Diermanse, 2022; Yousefpour & Hanewinkel, 2016). However, limited efforts have been made regarding their practicality in the real estate sector. This research seeks to address the fundamental question, “who pays what, when?”. At its core, this research revolves around the influence of climate risks on the investment decision-making process in polder-area developments in the Netherlands and examines the research question: “In which way do water risks impact the investment decision-making process in polder-area development projects in the Netherlands?”. In this qualitative study, the urban area development projects Westergouwe (Gouda) and Gnephoek (Alphen aan den Rijn) are compared and analyzed. With the use of explorative interviews, and semi-structured in-depth interviews, the research strived to answer the research question. Afterward, an expert panel is held to bridge the gap to standard practice. This research found that the integration of adaptive measures into the investment decision-making process is currently insufficient. There is a need for clear policy, clear distribution of responsibilities and prioritization of water safety over financial considerations in the investment decision-making process. By navigating this complexity, driven by collaborative efforts, a holistic approach becomes imperative to forge a path toward a more resilient built environment.","Climate adaptation; Climate risk; Water risk; Water management; Investment decision-making; Public-Private Partnerships; Polders; Low-laying development; Urban climate risk management; Urban Area Development; Real estate development","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:d4ad5520-3ca5-4ea6-87fa-a71bfaf5bc61","http://resolver.tudelft.nl/uuid:d4ad5520-3ca5-4ea6-87fa-a71bfaf5bc61","From Conflict to Value: Constructively Managing Conflicts to Enable Value Co-creation during the Front-end of Urban Redevelopment Projects","de Heus, Frank (TU Delft Architecture and the Built Environment)","Chan, P.W.C. (mentor); Ersoy, A. (graduation committee); Delft University of Technology (degree granting institution)","2024","This research explores the interdependent public-private relationship during the front-end of urban (re)development projects. During this process the municipality calls up on the developer's ability to drive change and innovation through the co-creation of value propositions. Inevitable conflicts emerge because of value pluralism and play a significant role in the co-creation of value propositions. However, in what ways real estate developers manage those emerging conflicts constructively and how this influences individual actor's value propositions is less known. Consequently, the following research question has been drawn up: ""How can real estate developers manage conflicts constructively to enable value co-creation during the front-end of urban redevelopment projects?"" In answering the research question this study applies a qualitative research method, using semi-structured interviews within a case study of an urban redevelopment program in the Netherlands. The findings display the dynamics of emerging conflicts during the co-creation of value propositions between developers and the municipality and the influence on individual actor value propositions. Understanding these dynamics, proactively steering on a good project environment to foster functional conflicts and utilise appropriate conflict handling styles enables developers to constructively manage conflicts during the front-end of urban (re)development projects.","value co-creation; value co-destruction; conflict management; emerging conflicts; value propositions; developers; municipality; urban redevelopment projects; front-end","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:07351967-5277-4489-b61a-7347b4e51197","http://resolver.tudelft.nl/uuid:07351967-5277-4489-b61a-7347b4e51197","Office of the Future: A Study on Office Reduction and Perceived Employee Productivity of Global Pharmaceutical companies in the Netherlands","Elders, Bente (TU Delft Architecture and the Built Environment)","Vande Putte, H.J.M. (mentor); van Bortel, G.A. (mentor); Delft University of Technology (degree granting institution)","2024","Restrictions from the covid pandemic are lifted. However, the office remains changed, the hybrid way of working seems to stick. Employees want flexibility and choose when to work from home and when they work in the office. The norm of a hybrid work week is working three days in the office and two days from home. Resulting in office space that is not used as much as before the pandemic. Therefore organizations are looking into reducing their office space (Syme, P., 2023).
When considering the reduction of office space, it is also important to consider an organization’s employees. In this research, the focus lies on the impact space reduction might have on the perceived productivity of the employees. The focus on productivity is due to the impact productivity has on the performance of an organization (Aziri, 2011). If office space is reduced and the office therefore has a higher occupancy level, what does this do to the employee productivity? According to research done by Center for People and Buildings (2023), a higher occupancy level in the working environment results in employees being less satisfied with the availability of workplaces. With a higher occupancy, employees are forced to have video meetings in the open workspace, while other employees/colleagues are doing concentration work in the same space at the same time (Center for People and Buildings, 2023). Looking at these uncertainties, the main research question therefore is: ‘How can global pharmaceutical companies reduce their office space in the Netherlands while still maintaining perceived employee productivity?’. The research focuses on global pharmaceutical companies that are reducing their office space. The focus lies on these companies, in order to define the research on a specific branch and due to the timeframe. In order to answer the research question, the research starts with a literature study. After the literature study, a series of case studies including interviews are done on global pharmaceutical companies. These companies have already experienced an office reduction and are planning on implementing a second reduction within the same project or with another project. The case studies provide insight into potential challenges concerning office reduction and maintaining employee productivity. After analyzing the case studies a cross case study analysis has been done. With the insights from the cross case analysis solutions have been found on how global pharmaceutical companies have tried to successfully reduce office space while keeping employee productivity. The research can help organizations with the decision-making on their office use.","Office reduction; Hybrid working environment; Perceived employee productivity; Office of the future; Global pharmaceutical company","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:7a86c434-ef73-4ea6-a3d6-4eb390b9e10b","http://resolver.tudelft.nl/uuid:7a86c434-ef73-4ea6-a3d6-4eb390b9e10b","Cargo Plus: The Cargo Terminal Design for Enhancing Working Conditions","CHEN, MENG (TU Delft Architecture and the Built Environment)","van Zalingen, J.M. (mentor); Eckardt, H.F. (mentor); Söylev, Y. (mentor); Delft University of Technology (degree granting institution)","2024","In today’s fast-paced and highly competitive global trade environment, cargo terminals have become crucial hubs for the transportation of goods. However, workers in these environments often face physically demanding tasks, such as heavy lifting, awkward body postures, harmful noise, and extreme temperatures. Besides, they also mentally face the mentally demanding working conditions, resulting from the time pressure, increasing complexity of logistics systems and the integration of advanced technologies. These factors have significant implications for employee health, well-being, and productivity, which in turn affect the overall efficiency of cargo operations.
The architectural design of cargo terminals has the potential to offset these demands and address the consequences by creating environments that actively support employee well-being. By exploring innovative design strategies that consider both functionally and mentally, architecture can play a crucial role in alleviating demanding working conditions,
promoting well-being, and boosting productivity within cargo terminals.
The project Architecture for the Displaced: One building representing the resettlement procedure in the arrival city of Berlin is about proposing a better building solution for both the institutions and the displaced. The project is a building bringing the resettlement procedure together, from arriving to going to court. The building is a pioneer in a more humanitarian approach towards getting refuge in Germany, by responding to the user's needs. The research question is: “How can a building treat displaced people in a societal inclusive way while maintaining institutional efficiency?”","Migration; Displaced People; Courthouse Architecture; Inclusive design; Berlin","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Complex Projects","Bodies and Building Berlin","52.50714864550195,13.430353205492667"
"uuid:f7623a82-2cd0-4037-bd4f-8226a10aa910","http://resolver.tudelft.nl/uuid:f7623a82-2cd0-4037-bd4f-8226a10aa910","New Cemetery: A museum of memories","XU, JIACHENG (TU Delft Architecture and the Built Environment)","van Zalingen, J.M. (mentor); Eckardt, H.F. (mentor); Söylev, Y. (mentor); Overschie, M.G.F. (graduation committee); Delft University of Technology (degree granting institution)","2024","What relationship can a cemetery have with the city?
Since the first garden cemetery was built in the early nineteenth century, this concept spread rapidly throughout Europe. Until now garden cemetery is still the common form of cemeteries in European cities. With the concept of garden cemetery, cemeteries exist in the urban fabric as a public space represented by nature and landscape attributes. The emergence of this relationship is closely related to the demand for burialbased burial forms. For a long time, this relationship has given the cemetery a natural and green identity, which is also the common perception of the cemetery among citizens.
Has this relationship changed?
In the context of the Complex Project, Building Body Berlin course, this research design will
focus specifically on Berlin, Germany. The existence of the German cemetery law, known as “Der Friedhofszwang“, makes cemetery burial mandatory in Germany. Along with this law of compulsory burials, the demand for cemeteries has a huge quantitative basis in Germany.
However, according to the research of cemetery development plan of Berlin in 2006, since the end of the 20th century, the cemeteries (mainly garden cemetery) in Berlin have roduced a large amount of vacancy. These idle cemeteries consume a lot of operating and maintenance costs. This phenomenon does not mean that the demand for cemeteries has declined. On the contrary, the demand for cemeteries in Berlin is still increasing. Moreover, with the aging of the population in Germany, the death rate and the number of deaths have risen, and Berliners’ demand for cemeteries will continue to increase in the future. The increase in demand for cemeteries does not appear to coincide with the reduction in cemetery size. It is this inconsistency that helps us see the problem for what it is. The reason for this lies in the transformation of the form of burials. As cremation has grown in popularity, people have increasingly turned to other forms of burial, such as burial of ashes and placement in columbariums. According to statistics, the proportion of cremation in Germany has reached more than 75%. Compared with the traditional form of burying coffins, the land area required for the new burial form represented by cremation is greatly reduced. Statistics show that compared with the average area of 12 square meters in traditional burial coffins, the average area of urns placed in columbariums is only 0.5 square meters. This huge change has also led to a continuous reduction in the core space actually used in the cemetery. Therefore, more and more cemeteries can no longer assume the role of urban public green space due to the reduction of the core use area.
Although this phenomenon of quantitative change has not accumulated to produce qualitative change, we can still see the urgent need for the transformation of the cemetery. So how can the cemetery provide a new value as an urban public space? This research design process will ask questions around this question and offer a possible solution.
This project highlights a significant knowledge gap in the effective integration of circular principles into the built environment at the neighbourhood scale and underlines the importance of social and environmental integration in research.
Previous research has identified significant vulnerability to climate risks and inadequate availability of nutritious, locally grown food, resulting in high levels of obesity and vulnerability to climate extremes in the selected post-war neighbourhood. In addition, the opportunity to separate organic waste from general waste is not fully realised, resulting in the loss of recyclable organic matter, which would have a great potential for energy transformation and introducing local agriculture. However, this waste separation needs to start in our daily lives. In contrast, food production takes place in isolation from our daily lives.
This raises the question: How can the transformation of Dutch post war neighbourhoods facilitate actions of our daily life towards a circular foodscape?
The main objective of this research project is to create a pattern language as a co-design method for the transition to a circular built environment in Dutch post-war neighbourhoods.
The creation of circular networks, such as mobility, sewage, heating infrastructure, and social networks that are interconnected, are very much needed to support the transition to a holistic circular system for everyday life in the respective neighbourhoods.
The project will use a design approach, conduct qualitative and quantitative research, and confirm the results with workshops and design development - in particular creating a pattern language. A systemic design approach will form the basis of this research and design process, as it embraces urban metabolism, co-creation and respects the diverse and complex nature of the project. The use of a pattern language as a research and design tool allows for the exchange of research and design through a co-creation approach and possible spatial implementations of a circular neighbourhood with circular actions in the everyday life of the inhabitants of Schalkwijk.
The primary outcome of this project is the design of a co-creation process, using the developed pattern language to show possible outcomes of a circular built environment. This includes bringing food production closer to our everyday lives and integrating circular systems within the local community. Urban planners have a facilitating role in presenting options for a circular future, starting processes that support the information and interest exchange of stakeholders, and providing participatory methods for shaping spatial circular strategies in post-war neighbourhoods.
The research highlights how outcomes can vary based on perspectives, interests, and needs during the co-creation process. While the study concentrates on the food system, it also recognises wider aspects of circularity within the built environment, such as water and energy supply. The unpredictable human element in the co-creation process affects workshop dynamics and results.
In short, this project aligns with the continual changes in sustainable development, participation, and circularity. It presents the pattern language as a useful tool for stakeholders working on circularity transitions, offering new opportunities for collaboration and resource efficiency at the neighbourhood scale. The findings contribute to filling existing research gaps by proposing a way to a sustainable, participatory, and circular urban development in Dutch post-war neighbourhoods.
Many InSAR studies use a batch estimation process requiring a robust algorithm to obtain reliable results. Here we propose a test recipe and introduce metrics to assess the robustness of the InSAR displacement estimates quantitatively, comparing the batch-estimated results of varying SAR acquisition inputs. Robustness characterizes the stability of displacement estimates in the face of disturbances and uncertainties, demonstrating resilience against changing conditions and input.
Our quantification of robustness involves three core metrics to assess InSAR displacement estimates.
Case studies conducted over the city center of Amsterdam and a coastal region at the North Sea reveal the useful insight provided by robustness testing in identifying ambiguities and fallacies in the applied algorithm. Notably, the main challenges arise from the estimation of atmospheric delay, which emerges as a sensitive step with ample room for enhancement. A robust atmospheric estimation appears very dependent on the use of a sufficiently large area of interest while the estimation is sensitive to first-order network changes.
Through the implementation of appropriate measures, an average metric improvement of a factor of four can be achieved, reducing the likelihood of a misinterpretation of the InSAR time series. This underscores the effectiveness of the proposed test recipe in improving existing InSAR software.","InSAR; displacements; monitoring; Atmospheric Correction; PSI","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:72aff18e-4bb7-40e6-b525-3999f679866a","http://resolver.tudelft.nl/uuid:72aff18e-4bb7-40e6-b525-3999f679866a","Standardisation in Healthcare Systems","van Veen, Aïcha (TU Delft Technology, Policy and Management; TU Delft Aerospace Engineering)","Grossmann, I. (mentor); Copeland, S.M. (graduation committee); van de Kaa, G. (graduation committee); Delft University of Technology (degree granting institution)","2024","The aim of this research is to gain an understanding of the balance between guideline standardisation and professional autonomy. This includes its impact on the safety and quality of healthcare. These are crucial aspects of providing good care as they can contribute to an overall healthcare system that is effective, reliable, and patient-centered. The reason for performing this research is the difficulty of finding a balance between guideline standardisation and professional autonomy. While guideline standardisation is crucial to ensure a structured approach to uniform care of high quality, professional autonomy is necessary to individualise this care for each patient. At times, the tension between these aspects arises as medical practitioners feel limited in their professional autonomy, but healthcare organisations require a structural set-up of healthcare systems to provide equal care.
By performing interviews with guideline developers, doctors, and patients, this tension and possible contributing factors were explored through a technical, human, and organisational perspective. The identification of a need for the inclusion of the psychosocial elements, research regarding sensitivity around professional autonomy, and structural changes is beneficial to get to a point where it is possible to identify a balance between guideline standardisation and professional autonomy and its impact on the safety and quality of care. While multiple points for further research are indicated in this study, these three factors contribute to improving the situation of both the tension itself and the discussions around it.
The total fuel cost savings for the small fleet are to 25% and 45% for the large fleet, which are similar on both days. On both days, outbound flights are most preferred direction to be towed due to the distribution of towing times. The savings per ETV are highest for a small fleet and decrease until all flights are towed. Furthermore, the load on the charging infrastructure at AMS for different fleet sizes shows what average
and peak power can be expected. It is shown that ETV utilisation and computation time can be improved significantly, by implementing costs on time and introducing utilisation and symmetry constraints. However, with the important limitation that these improvements are observed only for small planning horizons. Finally, a sensitivity analysis on charging power showed that increasing the charging rate has a positive impact on both fuel cost savings and the minimum number of chargers required. In conclusion, this study shows the potential impact of dispatch towing at AMS in terms of fuel savings, charging infrastructure and operational challenges.","Assignment Model; Balancing Constraints; Dispatch Towing; Electric Towing Vehicles; Mixed-Integer Linear Programming; Operations Research","en","master thesis","","","","","","","","","","","","Aerospace Engineering | Air Transport and Operations","","52.312957045589016"
"uuid:3ef77acb-b38b-4fa5-9b1e-31813b00b739","http://resolver.tudelft.nl/uuid:3ef77acb-b38b-4fa5-9b1e-31813b00b739","Inferring the residential building type from 3DBAG","Poon, Chris (TU Delft Architecture and the Built Environment)","León Sánchez, C.A. (mentor); Agugiaro, G. (graduation committee); Ibrahimli, N. (graduation committee); Delft University of Technology (degree granting institution)","2024","Urban Energy Modeling (UEM) provides a comprehensive approach to urban planning, helping to create sustainable, resilient, and energy-efficient cities that meet the needs of current and future generations. The key inputs for UEM methodologies and tools are the geometry of the building stock and its thermophysical properties. In the Netherlands, the 3DBAG provides the building stock geometry, while the thermophysical properties can be approximated using energy consumption estimates specific to each residential building type from the IEE project TABULA. However, a challenge arises as open data on residential building types at a national level is currently not readily available, necessitating the development of a method to infer this information from other accessible data sources.
In response to similar successful studies, this thesis also focuses on utilising machine learning to address this challenge. Support Vector Machine (SVM) and Random Forest (RF) algorithms were tested and compared. These algorithms were trained using data on the residential building types obtained from the Rijssen-Holten energy testbed and EP-online, with the latter requiring preprocessing to obtain the relevant information. Additionally, 25 features derived from cadastral data and building geometry underwent a selection process to identify the essential features for accurate classification of building types.
Eight models were trained and applied across eight case studies, containing subsets of the Netherlands representative for the whole country. The combined results were analyzed to determine necessary features, required data, and the most suitable machine learning approach for this research.
The results revealed that features such as adjacency to other buildings, width, and volume in LoD2.2 correlated the most with Dutch residential building types. However, critical features like the number of storeys, the presence of an open porch, or galleries were not available as open data, even though they directly relate to the definition of certain residential building types.
This thesis presented successful models, demonstrating accuracies between 61.1% and 98.5%, and balanced accuracies ranging from 51.6% to 94.2%. Importantly, performance differences were observed in various case studies, particularly in distinguishing accuracy between multi-dwelling and single-dwelling houses. Despite the longer tuning and training time, the suitability and accuracy of the RF models generally outperformed the SVM models.
These findings highlights the capacity of machine learning to attain robust classification outcomes for the Dutch building stock when trained on representative datasets. Nevertheless, it is emphasized that the accuracy of results is contingent on data quality, and difficulties may arise in scenarios involving intricate buildings with multiple components and ambiguous classification rules.","machine learning; building type; classification","en","master thesis","","","","","","","","","","","","Geomatics","",""
"uuid:75c8c337-0224-446c-a2e8-41817cf12349","http://resolver.tudelft.nl/uuid:75c8c337-0224-446c-a2e8-41817cf12349","The Place of In-Efficiency: Or the Place of Representation in Neo-Liberal Milan","Aragno, Aris (TU Delft Architecture and the Built Environment)","Pimlott, Mark (mentor); Rosbottom, D.J. (mentor); Mulder, K.B. (mentor); Mulder, André (graduation committee); Delft University of Technology (degree granting institution)","2024","This research attempts to develop a space in the city that, outside of the dynamics of consumption, but not denying the dialogue with the city, seeks to intertwine with its overlaps, by defining the public space of dialogue and representation. On the morbidity of performance and expectation, we might say that the contemporary Utopian intent, this thesis, regards defining a potential place, and its interpretive structure, devoid of expectations
– an in-efficient place.","theory of Architecture; utopia; neo-liberalism; efficiency; typology; Milan; city; park; void; interior building cities; Independent Group","en","master thesis","","","","","","","","2024-02-29","","","","Architecture, Urbanism and Building Sciences | Interiors Buildings Cities","","45.474251, 9.196318"
"uuid:0e4c3644-31a4-4157-983d-bd001d91b8ca","http://resolver.tudelft.nl/uuid:0e4c3644-31a4-4157-983d-bd001d91b8ca","Isogeometric Analysis of Wrinkling","Verhelst, H.M. (TU Delft Ship and Offshore Structures)","Möller, M. (promotor); den Besten, J.H. (copromotor); Delft University of Technology (degree granting institution)","2024","Wrinkles are ubiquitous in the world around us. In our daily lives, we encounter wrinkles in various forms, whether in our clothes or on our skin. Wrinkles emerge as a result of a delicate interplay between bending, membrane, and foundation stiffness contributions within membranes. While experimental investigations provide insights into the physics underlying wrinkling, numerical investigations find their purpose in the design, analysis, and optimisation of membranes subjected to wrinkling. Nevertheless, the numerical simulation of membrane wrinkling presents several challenges. Firstly, wrinkling constitutes a buckling phenomenon in membranes with low bending stiffness. Wrinkles have the potential to evolve into folds, creases, or other wrinkling patterns as loads or displacements increase. Secondly, the wavelengths of wrinkling can be orders of magnitude smaller than the overall geometry, requiring a small resolution of the numerical simulation and hence increasing computational costs. Overall, the question arises of how to design robust and accurate numerical models for the analysis of wrinkled membranes. This dissertation is subdivided into four parts and aims to provide answers to this question.
The first theme considers hyperelastic material modelling, with a focus on developing wrinkling models under large strains. The shell model employed in this dissertation is based on the isogeometric analysis paradigm. Specifically, the Kirchhoff--Love shell model is used, which leverages the higher-order continuity of underlying spline spaces. Chapter 3 extends hyperelastic material formulations to stretch-based materials, enabling the use of the isogeometric analysis paradigm for rubber-like shells. Since the modelling of wrinkling patterns imposes physical scales limiting element mesh sizes, chapter 4 introduces a hyperelastic isogeometric membrane element that incorporates an implicit wrinkling model, thus avoiding explicit modelling of wrinkling amplitudes.
The second theme addresses adaptive methods. On the one hand, spatial adaptivity enhances the local detail in a numerical simulation. Chapter 5 presents an adaptive isogeometric analysis framework based on intuitive goal functions, such as wrinkling amplitudes, to guide adaptive meshing routines. On the other hand, temporal or quasi-temporal adaptivity serves to enhance the efficiency of dynamic or quasi-static simulations. Chapter 6 introduces an adaptive parallel arc-length method. The method's adaptivity arises as a by-product of parallelisation efforts aimed at reducing computational times for quasi-static simulations.
The advantage of the smoothness inherent in the spline spaces used in isogeometric analysis is limited to simple topologies. To benefit from this smoothness in complex geometries, the third theme of this dissertation focuses on complex domain modelling. Chapter 7 presents a qualitative and quantitative comparison of unstructured spline constructions for multi-patch modelling using isogeometric analysis. This chapter offers insights and suggestions for future developments related to unstructured spline constructions.
The final theme of this dissertation concerns the reproducibility of the developed methods. In this section, design considerations are presented for an open-source software library, along with small examples, aimed at ensuring easy reproducibility and supporting future research in the three themes mentioned earlier.
In summary, this dissertation offers a wide range of methods for the isogeometric analysis of structural instabilities in thin-walled structures, including the modelling of wrinkling. The concepts developed in terms of hyperelasticity expand the applicability of wrinkling models to encompass large strains. The concepts developed in terms of adaptivity provide intuitive error estimators that drive local refinement in space, as well as a novel continuation method that eliminates the inherently serial arc-length methods. Through the use of unstructured splines, complex domains become accessible for the analysis of structural stabilities. By creating an open-source, forward-compatible software library, these concepts are made available for future developments in the field of isogeometric analysis of wrinkling.
Among the auxiliary subsystems, the Environmental Control System (ECS) is the largest consumer of non-propulsive power, accounting for up to 3-5% of the total fuel burn. The replacement of the conventional Air Cycle Machine (ACM) with an electrically-powered ECS based on the Vapor Compression Cycle (VCC) system could enable: i) a substantial decrease in fuel consumption; ii) a finer regulation of the relative humidity in the air distribution system, leading to improved air quality in the cabin and flight deck; iii) a reduction in maintenance costs and an increase in system reliability, due to the removal of the maintenance-intensive bleed system. However, the adoption of VCC systems in the aerospace sector has been historically very limited, due to safety concerns regarding the ozone depleting potential, toxicity and flammability of the working fluids used as refrigerants, as well as because of a lack of research specifically targeting airborne applications.
This dissertation documents research work performed as part of the NEDEFA project, which entails the investigation of VCC-based ECS architectures powered by oil-free highspeed centrifugal compressors. The first objective is to advance of the state-of-the-art regarding high-speed compressors operating with gas bearings, i.e., the key technological enablers of airborne VCC systems. The second target is to develop of a methodology for the integrated design of aircraft ECS, namely, a design philosophy in which the system and the main components are optimized simultaneously.
The main outcomes of this work are the development of a preliminary design model for high-speed compressors, extensively validated with experimental data and computational fluid dynamics simulations, and the implementation of an integrated design framework for aircraft ECS, embedding a multi-point and multi-objective optimization strategy. The compressor model has been applied to derive design guidelines for single-stage and twin-stage machines operating with arbitrary working fluids, as well as to perform the fluid dynamic design optimization of the compressor that will be installed in the IRIS (Inverse organic Rankine Integrated System) test rig of the Propulsion and Power Laboratory. Furthermore, the integrated design method has been used to size and compare the performance of two alternative ECS configurations for a single-aisle, short-haul aircraft resembling the configuration of an Airbus A320, i.e., a bleedless ACM and an electrically driven VCC. The results reveal that the optimal VCC system could be both more efficient and lighter than the corresponding ACM architecture, leading to potential fuel savings in the order of 20% for the prescribed application.
Space Filling Curve (SFC) has been explored as a good spaital access techniques for organizing point clouds. Existing SFC-based database solutions include PlainSFC, HistSFC, etc. However, they use a flat table to store point records and it is not compact for massive point clouds. In this thesis, a SFC-based database solution that manages point cloud in blocks is proposed. The purpose is to improve the performance of current point cloud database solutions, especially with storage space. This model organizes the point clouds based on Space Filling Curve, and innovatively splits each SFC key to a head and a tile. The points with the same SFC head are placed in the same block. SFC tails and other property dimensions are stored as arrays in other columns.
Compared with the pgPointCloud and Oracle SDO_PC, the intermediate SplitSFC prototype does not show significant advantage in storage and data retrieval efficiency so far. However, it is fair to believe that with the improvement of algorithms and implementations, it has the potential to be an approximate and efficient point cloud data management solution.","Point cloud; Space Filling Curve; Morton curve; spatial database; spatial data management","en","master thesis","","","","","","","","","","","","Geomatics","",""
"uuid:7cc6214b-61fc-4a57-9e55-259f697d2d05","http://resolver.tudelft.nl/uuid:7cc6214b-61fc-4a57-9e55-259f697d2d05","Biointegration of architecture and ecology system","Yang, Yuxin (TU Delft Architecture and the Built Environment)","Smit, M.J. (mentor); Tomesen, P.L. (graduation committee); Tillie, Nico (graduation committee); Louw, E. (graduation committee); Delft University of Technology (degree granting institution)","2024","Many species that are dependent on buildings are beginning to appear as more and more species of nature learn to adapt to city life. In the same vein, the concurrent loss of biodiversity presents a problem for the planning of vertical greening. This article attempts to explore the combination of animal nesting and vertical greening to develop a more species-friendly environment. The end goal is to create a flexible, easy-to-maintain, demountable, modular vertical greening system that can respond to changes in the ecosystem.","","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Architectural Engineering","",""
"uuid:65cf87da-aba2-4d4f-b66c-87de43d10582","http://resolver.tudelft.nl/uuid:65cf87da-aba2-4d4f-b66c-87de43d10582","The developer as low-emission supply chain initiator: A multiple-case study examining the supply-chain configuration and the developer’s role in implementing low-emission construction practices in Dutch inner-city high-rise projects.","Broekman, Jelmar (TU Delft Architecture and the Built Environment)","Vrijhoef, R. (mentor); Brancart, S. (mentor); Delft University of Technology (degree granting institution)","2024","class=""MsoNormal"">The construction industry is responsible for the emitting carbon, nitrogen, and particulate matter, which is harmful to the environment and contributes to global warming. Municipalities in the Netherlands plan to reduce emissions in inner-city developments to zero before 2030, for which a transformation of the already complicated construction supply chain would be necessary. The unique characteristics of the construction supply chain; temporary coalition of organizations working on one-of-a-kind projects, complicate reduction of supply chain emissions. In other sectors like manufacturing focal firms take in a central position between the demand and supply system and can align the supply chain. In construction the developer translates demands from society, the public and customers into projects that are executed by core supply chain stakeholders. The main question to be answered in this thesis is: How can real estate developers organize a low-emission supply chain for high-rise construction in Dutch cities? A literature review on green construction supply chain management and construction emissions have given insight into the drivers, barriers, and roles of different stakeholders in low-emission design, -procurement, -logistics and -construction & manufacturing. Inner-city high-rise case studies and semistructured interviews with relevant stakeholders within these projects were conducted to draw lessons from practice. Developers can have a big influence on construction emissions through setting ambitions and translating these low-emission ambitions in the criteria for the procurement of services and materials for all supply chain stakeholders. In design, close collaboration with the architect and early involvement of the contractor and relevant expertise can help implement low-emission practices. Logistics and construction & manufacturing emissions can be influenced through contractual agreements with contractors, subcontractors, and suppliers, but should not be a direct responsibility of the developer and ask for active involvement of the government.","Low-emission Construction,; Construction & manufacturing,; Procurement; Green Supply Chain Management; Multiple case-study; Real estate Developer; Inner-city high-rise Construction","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:39a7b856-088d-4a6e-a628-a70d9b3ba237","http://resolver.tudelft.nl/uuid:39a7b856-088d-4a6e-a628-a70d9b3ba237","Investigation into the resonance behaviour of the internal water column of an open-ended monopile","Mulder, Ernst (TU Delft Mechanical, Maritime and Materials Engineering)","Wellens, P.R. (mentor); Kalker, Edwin (mentor); Font, B. (graduation committee); Fiscaletti, D. (graduation committee); Fidalgo Domingos, D.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","The offshore wind industry is increasingly constructing wind turbines farther from the coast, in deeper water, and under more extreme conditions. This requires larger (monopile) foundations and necessitates new installation methods. An important factor affecting workability is the dynamic behavior of the monopile during installation.
The objective of this thesis is to develop a method for determining the hydrodynamic loads caused by internal sloshing in an open-ended monopile (MP) as it transitions from a horizontal to a vertical position in the splash zone.
First, the resonance frequencies of the internal water column are predicted with analytical approximations based on linear theory. Distinction is made between piston mode and sloshing. Two numerical methods, linear potential flow (LPF), and computational fluid dynamics (CFD) are used to verify the resonance frequencies. Since the CFD analysis is done in 2D, a 2D representation of the open-ended monopile is considered. Due to the presence of viscous effects in CFD, the resonance observed with CFD consistently occurs at a lower frequency than for the analytical and LPF methods. Also it is found that an decrease in inclination angle of the monopile with respect to the horizontal, while maintaining the same submerged length, results in lower resonance frequency for both piston mode and sloshing in both LPF and CFD.
To assess the accuracy of LPF in describing the motion of the internal water column, it is compared to the CFD model. Input excitation in the CFD model is low enough to avoid non-linear sloshing modes and other non-linear behaviour of the free-surface. The ComFLOW 2D CFD model has been validated against various works from the literature for the accurate representation of gap resonance frequencies.
For both the piston mode and sloshing resonance, discrepancies between the two numerical methods are found, which can be attributed to viscous effects. At resonance viscous effects are nonnegligible, therefore the LPF method over-predicts the severity of the piston mode and sloshing. The influence of both the submergence of the monopile and its inclination angle with respect to the horizontal is considered.
The hydrodynamic coefficients for added mass and damping are found with forced oscillation for both upright and inclined geometries. While good agreement is found between the LPF and CFD results away from resonance, the CFD results in the vicinity of the resonance frequency are used to tune the LPF model, by way of additional linear damping, to achieve more accurate results.
It can be concluded from the present work that the resonance of the internal water column near the first sloshing mode significantly affects the overall hydrodynamic force and must be taken into account. At the peak hydrodynamic force observed during the first sloshing mode, the sloshing induces forces 5.59 times higher (submergence of 5 meters), 3.62 times higher (submergence of 10 meters), and 2.33 times higher (submergence of 15 meters) compared to cases where sloshing is not considered.
Looking forward, it is strongly advised to conduct forced oscillation tests with larger amplitudes, as this explores the effect of non-linear chaotic sloshing. Additionally, expanding the CFD analyses to 3D, where more non-linear sloshing effects are expected, such as swirling, is recommended. Furthermore, given the differences in results between LPF and CFD, it is valuable to validate the findings through model experiments.
The Dutch drinking water companies face three major challenges regarding strategic investment decisions. First, the current sourcing and production capacity must be expanded to meet future drinking water demand. Second, there is a great demand for End-of-Life replacement of pipes in the drinking water infrastructure. Third, an investment challenge of a lesser financial magnitude but with an expected great impact on business operations is related to gaining operational control over the drinking water distribution network by integrating state-of-the-art sensor technology.
The outcomes of the internal decision-making processes of the drinking water utilities regarding these three strategic challenges will affect the stakeholders of the drinking water utilities. In addition, it offers possibilities for alignment with the goals of the other stakeholders. The main problem that this research seeks to address is a lack of engagement with drinking water utilities' stakeholders in the decision-making processes. A way to engage with stakeholders is by using Participatory Modelling, a technique that is not commonly applied by drinking water utilities.
These possibilities to engage stakeholders in the decision-making process are further backed by the development of new resources that have become available in recent years. These resources are new modelling techniques that have been applied in the field of drinking water research, in recent years. And, a novel perspective on multi-modelling e.g. the Multi-Model Ecology (MME) with Multi-Model Interface (MMI). In the current practice of research for Water Resource Management and other research for drinking water utilities, an MME and MMI (MME+I) have not yet materialised. This study aims to determine if an MME+I can benefit research for drinking water utilities and facilitate Participatory Modelling.
The Participatory Systems Design methodology (PSD methodology) is applied to generate a design for the conceptual model of the MME+I and the logical architecture for the MMI. A Proof of Concept (PoC) use case of model-coupling was applied. Here, an ABM model for Water Demand generates water demand patterns for an EPANET hydraulic model. This is a novel approach in hydraulic modelling for Dutch drinking water utility Oasen, since it introduces agents' behaviour from the ABM model to the modelling of hydraulic networks. It demonstrated that the outcomes of an ABM model affect the performance of the EPANET hydraulic model. In addition, It provided insight into how changes in water demand from scenario studies can affect strategic investment decisions for drinking water utilities.
Urban farming turned out to be the optimal industry to combine with dwelling. A physical connection might be optimal for the consumer binding, however to ensure the ideal production conditions the production is often limited to a visual connection. With this in mind, a new building typology was created that places the industry in the core of the building. Through this typology the residents and industry are connected within the building on all levels, as well as providing several sustainability benefits for the building.
The organizing and maintenance of communal activities has less to do with the architectural design and more about a motivated group of people that are willing to organize it. Nevertheless, communal farming presents a place where social interaction can flourish. As an activity the farming is consistent and low organizational, wherein other activities are harder to maintain. Consistency has shown to be the most important factor to make sure these activities are joined, while the kind of activity can be flexible. This led to the creation of a circulation concept, that makes space for the communal activities and support social interaction. A Helix circulation has been created to break the disconnect between different floors and create a ‘mini-city’ environment, similar to the public streets of the city. In addition, several other concepts has been developed, that can be used to support the creation of a community and promote social interaction for people that are socially isolated.
such as passive engagement, active engagement, relaxation and discovery. By methods of observational analysis, results are collected on the different ways in which people experience comfort while walking, standing and sitting at shopping centers. These show a strong relationship with the objects, functions, building design elements and natural design elements with the space.","Heritage & architecture; shopping centre; Comfort","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences","The Lijnbaan, Rotterdam",""
"uuid:ad545858-5b32-4f20-ad15-c44595d186b8","http://resolver.tudelft.nl/uuid:ad545858-5b32-4f20-ad15-c44595d186b8","First-time buyers on the Dutch housing market – the starters dilemma: Tackling the starters dilemma – Developers perspective. What are the desired housing preferences of first-time buyers and what trade-offs do they make during the decision-making process to buy an owner-occupied dwelling","Veerhoek, Evy (TU Delft Architecture and the Built Environment; TU Delft Management in the Built Environment)","Boumeester, H.J.F.M. (mentor); Hoekstra, J.S.C.M. (mentor); Delft University of Technology (degree granting institution)","2024","class=""MsoNormal"" style=""margin: 0cm 0cm 8pt; font-size: 11pt; font-family: Calibri, sans-serif; text-align: justify;"">""First-time buyer has a chance to buy only 3 percent of owner-occupied dwellings in the Netherlands” (NOS, 2023).
This quote reflects the harsh reality of single first-time buyers in the Dutch housing market. The substantial surge in housing prices has exacerbated challenges for first-time buyers since 2015 (Groot, 2022). The housing supply falls short in comparison to the demand in the Netherlands. Apart from the existing housing shortage, extended waiting periods in the social rental sector, exorbitant house prices, and the recent upswing in mortgage interest rates contribute to the scarcity of suitable options (Boelhouwer & Van Der Heijden, 2022). It appears that, mainly around the provinces comprising Randstad, the housing market is tight (Calcasa, 2023). The share of relocations from the rental market to the owner-occupied dwelling market has declined nationwide in recent years, while demand for owner-occupied dwellings has increased. Despite the government's possible attempts to address this housing shortage, for example, by building around 350,000 affordable owner-occupied or rental dwellings in the middle segment before 2030, availability and affordability remain a stumbling block for first-time buyers. By better targeting the construction of suitable ""starter"" dwellings, this problem can be addressed for the target group. Therefore, it is essential to consider the balance between the financial capabilities of the first-time buyers and the minimum desired living characteristics and living environment. To find the minimum desired characteristics of first-time buyers, it is important to look at their substitutional behaviour and the possible concessions they are willing to make, to meet the current housing prices.
Therefore, the aim of this research is to identify the preferences and considerations of first-time buyers in the Randstad region. It started with a literature review on the different theories behind the whole moving process, in order to then start the empirical research.
The empirical research initiated with a research on the Dutch housing market with a deepening focus on the Randstad region. Then to research how the financial position of first-time buyers is affected by government regulations and other factors. After gaining an understanding through research into the supply for first-time buyers and their financial capabilities, the housing preferences and considerations of this target group were mapped out utilizing a survey conducted among 326 respondents. Following MAUT's methodology, these respondents rated possible topics (attributes) and characteristics of these topics (attribute levels) to gain insight into their preferences. This quantitative research showed that respondents mostly preferred a corner dwelling with a garden in a suburban area.
Based on these findings, it can be concluded that first-time buyers highly value having a garden and a supermarket in the immediate vicinity, but also that the greatest preference, is not always the most realistic preference in view of financial capabilities. ","Owner-occupied housing market; First-time buyers; Housing preferences; Housing shortage; Multi Attribute Utility Theory (MAUT)","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:4d09de06-817e-42bf-8d5a-f36db2d773fb","http://resolver.tudelft.nl/uuid:4d09de06-817e-42bf-8d5a-f36db2d773fb","Urban Design Interventions for Creative Nightscapes in Rotterdam","Nguyen, Kimberley (TU Delft Architecture and the Built Environment)","Muñoz Sanz, V. (mentor); Goncalves, J. E. (graduation committee); Delft University of Technology (degree granting institution)","2024","Nocturnal cultural spaces in Rotterdam are under pressure of gentrification. The decline in night club spaces, also results in a decline in cultural innovation and experimentation. In current redevelopment plans for creative clusters such as Schieblock, show the replacement of the creative industry by homogeneous residential neighbourhoods or offices, with no cultural value. There is no long term vision for the creative industry, as they are stuck in a cycle of displacement and do not get the acknowledgement for adding value to the neighbourhoods of the future. By involving the creative industry and nightlife in urban design through a placemaking workshop and expert panel talks, the goal of this research is to bridge the knowledge gap between Dutch planning practices","nocturnal urbanism; nightscapes; nightlife; creative industry; action research; bottom up approach","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Urbanism","","51.925514, 4.475580"
"uuid:728a86ea-82e2-448b-b929-c8aa0490d6c4","http://resolver.tudelft.nl/uuid:728a86ea-82e2-448b-b929-c8aa0490d6c4","Exploring the effects of increased rent regulation and and taxation on the investment behaviour of private landlords in the Dutch housing market and the position of private tenants","Duurland, Jona (TU Delft Architecture and the Built Environment)","Boelhouwer, P.J. (mentor); Hoekstra, J.S.C.M. (graduation committee); Delft University of Technology (degree granting institution)","2024","The Netherlands is facing a housing crisis, marked by shortages and escalated prices. The Affordable Rent Bill aims to further regulate the private rental segment and improve the position of middle-income groups depend- ent on this segment. However, increased rent regula- tions and the recently introduced taxation measure Tax Plan 2023 decrease profitability for private landlords, sparking concerns about potential divestment from this segment, reducing availability and possibly worsening the position of private tenants and middle income groups. This study explores the effect of the Affordable Rent Bill and Tax Plan 2023 on the investment beha- viour of private landlords and the position of private ten- ants. Utilising inductive logic and a mixed-methods se- quential explanatory design, data from Woononderzoek 2021, a survey conducted among private landlords, and the consultation on the Affordable Rent Bill are ana- lysed. Its findings suggest that the accumulation of taxa- tion and rent regulation measures prompt private land- lords to divest a great number of dwellings, likely result- ing in a decrease in the availability of mid-market rental housing and a negative effect on the position of middle incomes and others dependent on this segment. The study underscores the need for a careful reevaluation of the regulatory framework to achieve the intended posit- ive effect on affordability and availability in the mid-mar- ket rental segment.","private landlord; rent regulation; taxation; mid-market rental segment; woningwaarderingsstelsel; private rent","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:9a0d757b-7852-4b35-b32a-0beb2d20a6e2","http://resolver.tudelft.nl/uuid:9a0d757b-7852-4b35-b32a-0beb2d20a6e2","Schalkwijk: a revitalised neighbourhood: a re-design of a seventies shopping mall","Rosenberg, Sofie (TU Delft Architecture and the Built Environment)","Meijers, W.L.E.C. (mentor); Tomesen, P.L. (mentor); Spoormans, L.G.K. (mentor); Delft University of Technology (degree granting institution)","2024","In recent years, shopping malls are facing an increasing amount of vacancy problems, due to the rise in online shopping. The research within this project looked into the visitors’ perspective concerning the functional, architectural, identifiable and social values of three shopping malls in the Netherlands. The outcome of the research shows that the visitors value the functional aspects of the mall most often, with everyday values such as ‘the grocery stores’, ‘the fact that the mall is nearby’ or that there are ‘a lot of shops’. From the outcome of the research, it could be concluded that the emphasis at the mall is on the necessary activities.
To create a place where a broader spectrum of activities will take place, the re-design of the Mall of Schalkwijk (Haarlem) focuses on a mix of functions with the addition of different dwelling types, offices, shops and green spaces. The connecting element in the project is the passage, which is repurposed from a closed traffic space to an open place to stay. The passage connects the shops and restaurants with a new square at the location of the old expedition space of the shops. An important factor in the design is the implementation of green to reduce the UHI effect and to increase human comfort at the site. Important interventions in the re-design are a boulevard with a green colonnade, façade gardens, green roofs and the quadrupling of the amount of trees on the site. To conclude, this re-design is an attempt to value what is already there and improve, making it ready for the future.
Our algorithm leverages semantic information for extrinsic calibration, striking a balance between network complexity and robustness. Future enhancements may include using machine learning to convert sparse matrices to dense formats for improved optimization efficiency.","Autonomous driving; Sensor fusion; Extrinsic calibration; Camera-LiDAR system; Edge registration","en","master thesis","","","","","","","","","","","","Electrical Engineering | Circuits and Systems","",""
"uuid:fb42614b-91ca-4347-bf3b-4562ba661e7a","http://resolver.tudelft.nl/uuid:fb42614b-91ca-4347-bf3b-4562ba661e7a","Solving Combinatorial Space-Routing Problems Using Mixed-Integer Linear Problem Solvers","Slimmens, Jasper (TU Delft Aerospace Engineering)","Dirkx, D. (mentor); Cervone, A. (graduation committee); Cowan, K.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","With the development of space research into novel areas, new complex problems arise. The interest in solving space routing problems considering large numbers of targets has recently grown. This paper proposes a novel method to solve the optimal trajectory in such combinatorial space routing problems. This paper focuses on a global optimisation algorithm implemented to solve the problem posed in the 4th Global Trajectory Optimisation Com- petition (GTOC4). The solution is a trajectory of multiple legs, where each leg links two targets and has a specific flight time. To enable the use of the powerful mixed-integer linear problem solver software, Solving Constraint Integer Programs (SCIP), the routing problem concerned with visiting as many target bodies with a predetermined fuel and time budget is split into linear sub-problems. The Fixed Budget sub-problem selects a subset of the given set of targets. The Full Tour sub-problem orders the targets in the subset, and the Fixed Tour sub-problem optimises the flight time for every leg of the given trajectory to find the solution with the lowest total fuel consumption. Each of these sub-problems is formulated in a linear form and is solved using SCIP. The global optimisation algorithm evolves a population where every individual exists of a set of initial guesses for the time of flight values. Analysis shows that initialising this population with a mix of randomly generated individuals and individuals containing a constant value for all entries leads to the fastest convergence towards the optimal solution. In a population of 20, seeding ten individuals is found to be optimal. It is also found that the algorithm performance can be further increased by evolving individuals with infeasible solutions instead of iterating them until a feasible solution is found and eliminating the Full Tour sub-problem. These simplifications allow for an increase in the cost budget multiplier, which leads to finding better objective values without further increasing computational time. The best-performing setup, which uses a cost budget multiplier of 10, can find the optimal solution to the test problem in 100% of the runs, on average in 9 iterations, with a computation time of 5.82 seconds per evaluation. The results show that the global optimisation algorithm produces results that closely match known results for GTOC4 consistently and accurately.","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:848ede19-3950-4bf7-a4fa-e702b24d4a0c","http://resolver.tudelft.nl/uuid:848ede19-3950-4bf7-a4fa-e702b24d4a0c","Berlin's Kitchenlab","Rademakers, Pelle (TU Delft Architecture and the Built Environment)","van Zalingen, J.M. (mentor); Eckardt, H.F. (graduation committee); Söylev, Y. (graduation committee); Chen, Y. (graduation committee); Delft University of Technology (degree granting institution)","2024","The Berlin’s Kitchenlab bridges the gap between highly specialised culinary education and the community. As a school that acts like a social catalyst for its surroundings. The building is located in Otto Park in Alt Moabit, an upcoming area, surrounded by food venues at the end of a public axis. The building consists of a central street with a public program surrounded by other specialised programs, resulting in a building that is easily accessible by the public while still tailored towards the program’s specific needs, like the distribution of food and support functions. All functions are situated on the façade making the building a frame that displays all contents. This makes the culinary university move past a traditional cooking school and become valuable for its immediate and broader surroundings.","University; Berlin; Complex Projects; Culinary; Bodies; Building","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Complex Projects","","52.525662910743776, 13.336444703479138"
"uuid:764932ec-de84-42e0-b633-7da7e1390925","http://resolver.tudelft.nl/uuid:764932ec-de84-42e0-b633-7da7e1390925","A reliable modulation scheme for body coupled communication with galvanic coupling","Haarman, Mart (TU Delft Electrical Engineering, Mathematics and Computer Science)","Venkatesha Prasad, Ranga Rao (mentor); Narayana, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis explores the integration of (Frequency Shift) Chirp Spread Spectrum Modulation (FSCSSM) in Body Coupled Communication (BCC) using the Galvanic Coupling (GC) method. The goal is to provide a method of private communication in a noisy channel for devices in and around the human body. Various parameters, including frequency, electrode dimensions, electrode inter-distances, and noise levels, are evaluated. Results demonstrate that FSCSSM allows reliable communication in highly noisy channels, achieving a data rate of 9.6 kbps at a Signal-to-Noise Ratio (SNR) of -9dB. The impact of body composition is highlighted, showing its significance in single-body communication. The communication in single-body is extended by evaluating body-to-body communication, enabled by touch, as well. This research provides valuable insights for designing robust BCC-FSCSSM systems.","","en","master thesis","","","","","","","","2026-01-19","","","","Electrical Engineering | Embedded Systems","",""
"uuid:560fb7a5-132b-4e74-85e8-1cead18ca28a","http://resolver.tudelft.nl/uuid:560fb7a5-132b-4e74-85e8-1cead18ca28a","Chromosome metamorphoses: on the atypical roles of condensin II","Hoencamp, C. (TU Delft BN/Benjamin Rowland Lab)","Rowland, B.D. (promotor); Haarhuis, Judith (copromotor); Delft University of Technology (degree granting institution)","2024","Every human being originates from a single fertilized egg cell, continuously duplicating to form a body consisting of trillions of cells in a process known as the cell cycle. This cycle involves two major stages: interphase, where the cell prepares for division, and mitosis, where it divides into two daughter cells. The accurate duplication and distribution of DNA during this process are crucial to prevent errors like cancer development.
A cell, around 10 micrometers in diameter, contains approximately two meters of DNA, divided into 46 chromosomes. These chromosomes need to be tightly folded to fit within the cell, but during interphase, they must also be accessible for protein interactions. In mitosis, chromosomes take on the X-shape, driven by a molecular machine called condensin, part of the SMC complexes family, essential for DNA folding at different cell cycle stages.
Condensin, known for shaping mitotic chromosomes, comes in two types in humans: condensin I and condensin II. This thesis explores the functions of condensin II beyond mitotic chromosome structuring. In Chapter 3, research on 24 organisms reveals diverse chromosome organization during interphase, with condensin II influencing the transition from chromosome territories to Rabl-like organization. Removal of condensin II in human cells shifts their organization.
Chapter 4 examines the impact of condensin II removal on chromosome territories in human cells, concluding that different levels of genome organization operate independently. Removing condensin II minimally affects gene expression, suggesting chromosome territories' limited role in regulating genes.
Chapter 5 investigates how condensin II prevents Rabl-like organization and centromere clustering, finding its specific role during or after mitosis. The data indicates that condensin's role in shortening the chromosome axis is crucial in preventing centromere clusters.
Chapter 6 contextualizes findings, proposing a model on how condensin II may control interphase organization based on data from Chapters 3 to 5.
Chapter 7 shifts focus to condensin II's negative regulator, MCPH1, inhibiting condensin II in interphase. Removing MCPH1 leads to interphase condensation, affecting DNA distribution during cell division. Condensin II, typically working with topoisomerase 2, encounters difficulties in untangling DNA knots when MCPH1 is absent.
This dissertation highlights the importance of balancing condensin II, investigating the consequences of its loss and over-activation. Both scenarios significantly impact cell function, emphasizing condensin II's broader role beyond mitotic chromosome organization. The research contributes fundamental insights into condensin biology, offering potential for new discoveries in this field.","Chromosome biology; Molecular biology; SMC complexes; Condensin; Cohesin; chromosome condensation; Genome organization; Chromosome","en","doctoral thesis","","978-94-6483-646-2","","","","","","2025-01-18","","","BN/Benjamin Rowland Lab","","",""
"uuid:06f70a6f-38a6-48c0-a04e-023d7a9e0b15","http://resolver.tudelft.nl/uuid:06f70a6f-38a6-48c0-a04e-023d7a9e0b15","COLLECTIVE INTIMACY: Revive the collective housing as a utopian oasis","Wu, Xinyue (TU Delft Architecture and the Built Environment)","Rosbottom, D.J. (mentor); Mulder, K.B. (mentor); Pimlott, Mark (mentor); Delft University of Technology (degree granting institution)","2024","In case you feel confused, this is an architecture project based on research which in total took one year. The process was never linear, but the narrative has to be.
For the first six months I studied the essential values of collective housing in post war period, how they prompted to solve housing crisis and how they embraced the collectivism in Europe and China. It turned out that most of them did not maintain the original function as a collective housing for working class. However, the concept of collective living continued to influence urban life. In response, the design approach for renovating the 1952 Workers' New Village in Shenyang, China aimed to demonstrate the potential for reviving this old form for communal living. Minimal intervention and adjustments to thresholds resulted in the creation of a series of spaces ranging from private to public, catering to the demands of the free market and post-urbanization.","Socialist housing; Collective living; Heritage Preservation; Shenyang Workers' Village; minimum intervention; layers of intimacy","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Interiors Buildings Cities","","41.799999, 123.400002"
"uuid:573a34dd-b90e-4d54-a636-f94e6d1f7f3e","http://resolver.tudelft.nl/uuid:573a34dd-b90e-4d54-a636-f94e6d1f7f3e","Designing a Smart Speculum for Low Resource Settings: The Impact of Contextual Factors on the Design of a Point of Care Cervical Cancer Screening Device","Bruggen, Femke (TU Delft Industrial Design Engineering)","Diehl, J.C. (mentor); Chmarra, M.K. (graduation committee); Delft University of Technology (degree granting institution)","2024","Cervical Cancer (CC) is a preventable disease and is easily treated when detected early. Yet it is the second most prevalent cancer related death in Cameroon, causing an estimated 1787 deaths each year (Woks et al, 2023). Cameroon has implemented no national strategy to prevent this disease and so screening practices that are in place are sporadic and scattered, causing a low national screening coverage of 6%, indicating a gap in the current healthcare landscape.
Apart from the issues regarding obtaining screening coverage, the screening method that is most commonly used in Cameroon due to the resource limited nature of the setting, is Visual Inspection with Acetic Acid (VIA). However, this method has significant limitations regarding accuracy and poses a barrier for women to undergo them due to its dependence on the use of a speculum. These limitations decrease the effectiveness of the screenings efforts that are made only further. Therefore the need for a comfortable, speculumless Point of Care (POC) CC screening device, which offers an increased accuracy, yet retains the accessibility that is associated with VIA, is identified.
In order to create such a device and contribute to an increased CC screening coverage in Cameroon, this thesis identifies and explores these gaps and in response creates Use Case Scenarios that both propose a solution for the current gap in the healthcare system and demonstrates the future context of use of this new device.
Additionally it seeks to adjust, complement, and tailor the set of Design Criteria established by the WHO for Point of Care (POC) Diagnostic tests, called ASSURED, to suit the requirements of a POC cervical cancer screening device (WHO, 2006; WHO, 2023) in order to guide the development of a new POC CC screening device that addresses the need of the end users in a local healthcare context.
Lastly it combines both these elements into a design tool that helps designers to understand how relevant contextual factors may impact the design of a CC screening device in different contexts of use. By making this an interactive experience, it tries to share complex contextual insights by making them comprehensive, yet retaining their complexity and minimizing the loss of depth during knowledge transfer.
The primary focus of this thesis involves two physiological studies comparing the effects of a new flow-controlled ventilation (FCV) mode with pressure-controlled ventilation (PCV) in ICU patients. FCV, characterized by constant flow during both inspiration and expiration, holds promise for its potential lung-protective effects. The effects of FCV on lung physiology are assessed by using several advanced respiratory monitoring techniques, such as electrical impedance tomography and esophageal pressure measurements. The first study evaluates the effect of FCV versus conventional PCV on lung physiology in ICU patients who required postoperative mechanical ventilation following cardiothoracic surgery, a group characterized by relatively 'healthy' lungs. The second study is an ongoing study in ICU patients requiring mechanical ventilation for respiratory failure due to moderate to severe ARDS, for which preliminary results are presented.","Flow-controlled ventilation; Intensive Care Unit; Electrical impedance tomography","en","master thesis","","","","","","","","2025-12-20","","","","Technical Medicine | Sensing and Stimulation","TM30004; 35 ECTS",""
"uuid:54e862d6-a50a-4e9f-ab0b-c429657e9802","http://resolver.tudelft.nl/uuid:54e862d6-a50a-4e9f-ab0b-c429657e9802","Fault Tolerant Control Barrier Functions","van Hilten, Quinten (TU Delft Aerospace Engineering)","de Visser, C.C. (mentor); Delft University of Technology (degree granting institution)","2024","In this article a novel Control Barrier Function (CBF) named the fault tolerant Control Barrier Function (ftCBF) is introduced. The ftCBF is able to keep a vehicle within a predefined safe set with changing control bounds and changing system dynamics. The ftCBF is shown to be feasible in fault tolerant control applications, as opposed to existing CBF methods. This novel constraint is tested on a double integrator system, and on a non-linear Dubin’s Car system with changing system dynamics and changing control bounds. In the simulations it is shown that the ftCBF is able to keep the vehicle in the safe set with failure events occurring at any place in the timeline. The ftCBF contains design parameters that allow a trade-off between safety and performance.","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:599af64f-75b7-47d6-900a-93f0e3589792","http://resolver.tudelft.nl/uuid:599af64f-75b7-47d6-900a-93f0e3589792","Artifact-Free Neurostimulator with Arbitrary Waveform Generation for High-Channel, High-Density Bidirectional Neural Interfaces","Chen, Hsukang (TU Delft Electrical Engineering, Mathematics and Computer Science)","Muratore, D.G. (mentor); Abdelgaliel, B.H.B.M. (mentor); Pertijs, M.A.P. (graduation committee); Serdijn, W.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","To achieve greater specificity in neurostimulation, bidirectional neural interfaces are required to verify the recorded neural response after stimulation. The specific neural interface targeted in this thesis is the epiretinal implant. Due to the heterogeneity of the retinal ganglion cells (RGCs), high-fidelity vision is only possible when all the types of RGCs near the neurostimulator are mapped. This necessitates the bidirectionality of the implant and poses significant difficulties, as large stimulation artifacts obscure the small neural response that needs to be recorded. Furthermore, in order to cover a large area of the retina, a channel count in the order of 104 will be required. Scaling existing neurostimulators would lead to chips that are >30mm2, which is too large.
The aim of this thesis is therefore to design a neurostimulator for the epiretinal implant that is capable of implementing artifact-reducing algorithms, and is smaller than the current state-of-the-art. The proposed system makes use of a mismatch-based digital-to-analog converter (DAC), and has been optimized for an output range of 0-6 μA at an effective resolution of 8-bits. Furthermore, in order to decrease the amount of stimulation units required, waveform interleaving has been proposed, where the anodic and cathodic stimulator are separated. A voltage compliance monitor is also designed to ensure proper stimulation output. The designed system has been fabricated and occupies 0.0003mm2 for two channels. Scaling this directly to 104 channels would result in an area of 1.645mm2. This area can be reduced even further via electrode multiplexing, which the designed system readily allows for. An output availability (i.e. how many input codes are possible after calibrating) of 99.2% and 97.3% is reported for the anodic and cathodic stimulator at an 8-bit resolution over the full output range.","DAC; Neurostimulator; Arbitrary waveform generator","en","master thesis","","","","","","","","2026-01-17","","","","Electrical Engineering | Microelectronics","",""
"uuid:a0885ea5-3fa5-4fa8-a350-6f2c04f6c65c","http://resolver.tudelft.nl/uuid:a0885ea5-3fa5-4fa8-a350-6f2c04f6c65c","Model-based motion optimization for quadruped robots with an actuated articulated torso","Kockelkoren, Michiel (TU Delft Mechanical, Maritime and Materials Engineering)","Shi, S. (mentor); Mazo, M. (mentor); Della Santina, Cosimo (graduation committee); Zhang, Luyao (graduation committee); Delft University of Technology (degree granting institution)","2024","In recent years, the deployment of ground-based mobile robots has gained more and more interest in various domains. In contrast to other types of mobile robots, legged robots can traverse irregular terrains, climb stairs, and step over obstacles. However, these unique properties intensify the energy demand and require highly advanced perception methods, actuator designs, and motion control algorithms. The most significant challenges in legged robotics lie in robustness, energy efficiency, and agility.
In recent years, the integration of an articulated torso or active spine, inspired by the body motion of high-performance mammals like the cheetah, has shown promising results. Various studies observed higher maximum velocities and lower energy consumption compared to a rigid torso. However, in these studies, the compliant systems were typically controlled using basic control strategies. In recent years, the development of highly dynamic model-based motion optimization strategies has greatly enhanced the overall performance of various legged robots. Therefore, a model-based motion optimization scheme is developed specifically for articulated quadruped robots. This scheme fully exploits the additional degrees of freedom of the torso to enhance the dynamic performance of the legged robot further.","Legged Robots; Quadruped; spine; Trajectory Optimisation; Motion planning; Motion and Path Planning; Dynamic modeling; centroid-based routing; model-based optimization; Model-based planning; Planning algorithms; Actuated spine; Articulated torso; Legged locomotion","en","master thesis","","","","","","https://gitlab.com/kockelkorenmichiel/compliant_spot.git Gitlab repository https://www.youtube.com/playlist?list=PLmZ4ovuqQhMDMwtWewSW37cCfZYxINFxL Unspecified Videos","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:913087dc-4306-4a93-b89e-b6bc5a037772","http://resolver.tudelft.nl/uuid:913087dc-4306-4a93-b89e-b6bc5a037772","Low cost power quality measuring unit for household usage and small to enterprise scale installations: Designing a Low Cost Power Quality Analyzer","Bouma, Eline (TU Delft Electrical Engineering, Mathematics and Computer Science); Damoiseaux, Luke (TU Delft Electrical Engineering, Mathematics and Computer Science); Groeneveld, Jorik (TU Delft Electrical Engineering, Mathematics and Computer Science)","Lekić, A. (graduation committee); Palensky, P. (graduation committee); Koornneef, R.N. (graduation committee); Renzaglia, S. (mentor); Lager, I.E. (graduation committee); Delft University of Technology (degree granting institution)","2024","The increase in non-linear loads of modern electronics raises concerns over power quality. Additionally, existing power-quality analyzers are expensive and not intended for household use. This thesis aims to develop a single-phase, user-friendly power-quality analyzer using a Raspberry Pi 4 Model B with an emphasis on low cost and class S specifications. The design was split into modules consisting of analog to digital conversion, voltage sensing, and current sensing. Sub-modules were added for circuit protection and PCB. Various approaches are discussed before circuit design, simulation, and testing occur. A functioning prototype was assembled on a dedicated PCB while not exceeding the set budget of €250.00. However, it could not be determined whether the class S specifications were achieved due to insufficient testing. A variety of improvements have been suggested.","Power Quality; electricity grid; power measurement","en","bachelor thesis","","","","","","","","","","","","Electrical Engineering","EE3L11 Bachelor graduation project Electrical Engineering",""
"uuid:1b2538aa-e4aa-4bc9-9b29-608b65c13a18","http://resolver.tudelft.nl/uuid:1b2538aa-e4aa-4bc9-9b29-608b65c13a18","Designing Software for User-Friendly Class-S Power Quality Analyzer based on Raspberry Pi","Yildiz, Hüsna (TU Delft Electrical Engineering, Mathematics and Computer Science); de Vries, Marten (TU Delft Electrical Engineering, Mathematics and Computer Science); Öztürkoglu, Emirhan (TU Delft Electrical Engineering, Mathematics and Computer Science)","Lekić, A. (graduation committee); Palensky, P. (graduation committee); Koornneef, R.N. (graduation committee); Renzaglia, S. (mentor); Lager, I.E. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis describes the design of a low-cost class-S power quality analyzer based on a Raspberry Pi 4. Capable of detecting power frequency, magnitude, voltage dips and swells, harmonics, and total harmonic distortion, the project consists of four main components: the communication protocol, the interface, the algorithms for power quality parameters, and the database. Each with its subdivisions. The communication module, which uses the I2C protocol, is chosen for its high sampling rates and built-in acknowledgement system, ensuring robust and fast operation. The interface module features a secure login process with two-step verification, a graphical user interface for real-time monitoring, and integration with algorithms for power quality parameter calculation. The algorithm module includes Fast Fourier Transform for harmonic detection, zero crossing method for power factor and frequency, and peak detection for voltage dips and swells. The database, powered by MariaDB on Raspberry Pi 4, securely manages the received data with restricted access for increased security, allowing remote access only from specified IP addresses.","Power Quality; Raspberry Pi; Database; Interface; User-friendly; ADC; Sampling","en","bachelor thesis","","","","","","","","2026-08-01","","","","Electrical Engineering","Low cost power quality measuring unit for household usage and small to enterprise scale installations",""
"uuid:35fab3d8-4a9b-4a0f-98d4-b0ad8dbf1385","http://resolver.tudelft.nl/uuid:35fab3d8-4a9b-4a0f-98d4-b0ad8dbf1385","Between a Day and a Lifetime: Integration of short-stay housing and the sharing economy in the post-war neighborhood of Groot-IJsselmonde, Rotterdam","Hietbrink, Cedric (TU Delft Architecture and the Built Environment)","Mooij, H.A.F. (mentor); Eckardt, H.F. (mentor); Guis, R.S. (mentor); Cuperus, Y.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Urban densification is essential to keep the green spaces surrounding Dutch cities, especially in the Randstad. The current Dutch housing stock, of which a significant portion was built during the 1960's and 1970's, lacks a flexible layer in which people in urgent need of housing can find (temporary) affordable housing. Short-stay housing, which encompasses people living somewhere for a day, up to a couple of years, could provide this flexible layer. Target groups for short-stay housing fare well by social interaction, stimulating integration into Dutch society and opening up new possibilities in their life. This social interaction can be partially provided by introducing the sharing economy into an existing neighborhood, providing sustainable options regarding ownership or mobility.
The project 'Between a Day and a Lifetime' therefore proposes an urban densification strategy in which a short-stay housing concept, based on principles of co-housing and the sharing economy, creates densification in a way that it enriches the lives of the current ánd future inhabitants.","Short-stay housing; Co-housing; Sharing economy; Urban densification; Social interaction","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Advanced Housing Design","","51.885404, 4.558363"
"uuid:b54561bd-1141-429f-83e3-a94b966c7a07","http://resolver.tudelft.nl/uuid:b54561bd-1141-429f-83e3-a94b966c7a07","Global impacts of aircraft emissions on air quality and nitrogen deposition","Domingos de Azevedo Quadros, F. (TU Delft Aircraft Noise and Climate Effects)","Snellen, M. (promotor); Dedoussi, I.C. (copromotor); Delft University of Technology (degree granting institution)","2024","Global passenger air traffic has doubled in the 13 years prior to 2019, and is expected to double again over the next 20 years or so. Growing demand for aviation is met by a corresponding increase in jet fuel being burned by aircraft, releasing multiple pollutants into the atmosphere. Besides disturbing the Earth’s radiative balance, these emissions also lead to excessive deposition of reactive nitrogen, and to a degradation of air quality. Anthropogenic nitrogen deposition damages vulnerable ecosystems, while degraded air quality is associated with increases in human mortality rates. These last two environmental impacts can be very localized, but, owing to the high altitude of emissions, they also occur over intercontinental distances. This thesis aims to evaluate the magnitude of air quality and nitrogen deposition due to emissions from civil fixed-wing aircraft at a global scale, and how these impacts might change in the coming decades.","Aviation; Air quality; Air pollution; Aircraft emissions; Nitrogen deposition; Intercontinental pollution; Public health; Atmospheric chemical transport model","en","doctoral thesis","","","","","","","","","","","Aircraft Noise and Climate Effects","","",""
"uuid:7defbd1e-dcbd-421e-aba5-2a58009a1329","http://resolver.tudelft.nl/uuid:7defbd1e-dcbd-421e-aba5-2a58009a1329","Towards a transition territory: Planning and design strategies to improve social and ecological conditions in the peri-urban area of Shanghai","Xu, Shiming (TU Delft Architecture and the Built Environment)","Furlan, C. (mentor); Qu, L. (graduation committee); Nottrot, R.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Shanghai has experienced rapid urbanization over the past 30 years, with a large number of rural areas being transformed into semi-urbanized areas with mixed functions. The main drivers were top-down state-led development, market forces, and bottom-up rural industrialization. The scale and speed of this process have far exceeded expectations, leading to a series of socio-ecological problems such as population loss, industrial decline, and environmental pollution. Based on the analysis, this dissertation identifies two development directions: industrial restructuring and ecological protection, to cope with the uncertainty of population growth, a scenario-building approach is used to explore the optimal strategies under different circumstances. Design strategies are extracted through scenario evaluation and applied to strategic planning.","peri-urban areas; scenario building; urban design; Shanghai","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Urbanism","",""
"uuid:ca28ecd8-2137-4dc7-9786-d3849d3b55e0","http://resolver.tudelft.nl/uuid:ca28ecd8-2137-4dc7-9786-d3849d3b55e0","Planning for justice: A value-based framework to help spatial planners develop just housing strategies in Dutch regions","Koch, Matthijs (TU Delft Architecture and the Built Environment; TU Delft Urbanism)","Viseu Cardoso, Rodrigo (mentor); Kleinhans, R.J. (graduation committee); van der Putt, P.S. (graduation committee); Delft University of Technology (degree granting institution)","2024","The current Dutch housing domain is characterised by injustices on multiple scales, such as a shortage of housing, disparities in well-being across regions, and unaffordable housing. This situation can partially be attributed to spatial planning practices focused on promoting growth-oriented economic thinking. These contemporary planning practices can be argued to be socially and spatially selective and to have a short time horizon. While some injustices remain unresolved, others are exacerbated by contemporary planning practices. The aim of this research has been to develop a justice framework which helps spatial planners address, instead of perpetuate injustices. This is approached through the question: To what extent can a framework based on justice values help spatial planners design for justice in the housing domain in Dutch regions?
This has led to the development of a justice framework constructed from three core justice values: Sufficiency, Limitation and Opportunity. These are made more concrete to the housing domain through two applied values each: (I) Availability and (II) Acceptability for the quantitative and qualitative aspects of Sufficiency; (III) Sustainability and (IV) Moderation dealing with intergenerational justice and intragenerational justice for Limitation; and (V) Influence and (VI) Diversity related to opportunities to assert influence on the living environment and to choose a living environment. These applied values are further specified using housing dimensions and strategy directions in two consecutive rings.
The first advantage for spatial planners is that the justice framework summarises and combines several abstract justice theories into digestible values relevant to the Dutch context. To test and demonstrate the justice framework it has been applied to the case study area of the Regio Stedendriehoek, which enabled answering the research question. First the justice framework helps to structure regional spatial analysis and policy analysis on a wide range of justice values, which can bring to light different types of injustices. Second, based on the analyses, clusters can be made of areas with similar problems regarding the applied values, which helps determine which type of strategies require priority in different areas. Then, based on these priorities, strategies can be developed using the outer ring of the justice framework. The justice framework helps to structure strategy development per applied value, but the justice framework can also be used as a tool to assess whether strategies can contribute to solving injustices for different applied values. In this way fruitful strategies can be prioritised and interventions that cause conflicts between different justice values can be avoided or mitigated.","Spatial justice; Strategic framework; Spatial planning; Stedendriehoek; The Netherlands; Housing justice; Well-being","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Complex Cities","","52.270202, 6.170599"
"uuid:e1fdfc2b-c0e3-4c02-bb78-cdbf0cc10c1a","http://resolver.tudelft.nl/uuid:e1fdfc2b-c0e3-4c02-bb78-cdbf0cc10c1a","Exploring the potential of explorative point clouds in floodplain maintenance","Sterkman, Pam (TU Delft Architecture and the Built Environment)","Verbree, E. (mentor); Meijers, B.M. (graduation committee); Lindenbergh, R.C. (graduation committee); Pleizier, I. (graduation committee); Delft University of Technology (degree granting institution)","2024","Water management is an integral part of Dutch history, driven by the continuous need to reduce flood risk. Because a large area of the country is located below Normaal Amsterdams Peil (NAP), there is an ongoing challenge to safely discharge all the water to the sea. Therefore, flood safety policy has become crucial to protect the Netherlands from natural hazards. An essential part of this strategy involves the Waardegedreven Onderhoudscontract Uiterwaarden (WOCU) Rijntakken project, which is responsible for managing the floodplains adjacent to the Rijntakken within the Netherlands.
The current lack of efficiency and effectiveness regarding change inspection in the large and sometimes inaccessible areas of the floodplain requires the use of remote sensing change detection to move toward a data-driven maintenance process, in particular, by using point cloud data. This is nowadays a widely used data source in a variety of fields to capture elevations and in this way extract valuable information from terrains. Despite its usage in a variety of applications, the data is often underused since the data is frequently processed directly to other data formats. This research therefore aims to reveal the potential of explorative point clouds in floodplain maintenance.
Light Detection and Ranging (LiDAR)- and multispectral data were acquired at two moments, one before and one after the summer, with a time interval of 45 days. Subsequently, these acquired datasets evolved into an explorative point cloud by adding attributes, including vegetation health, also known as Normalized Difference Vegetation Index (NDVI), and the distance between these two point clouds, the cloud-to-cloud distance. This explorative point cloud with the integrated additional information was visualised to several disciplines involved in the WOCU project. This was done in Three Dimensional (3D) by using Virtual Reality (VR). This collaborative approach revealed the potential use cases of the Red, Green, Blue (RGB), cloud-to-cloud distance, and NDVI point clouds highlighting the potential of explorative point clouds.
Potential use cases that were found are; highly detailed area modeling, vegetation overgrowth monitoring, bank erosion detection, flora status assessment, monitoring of vegetation types, digital inspection of remote sites, participation medium, and identification of atrophied ground patches. Attributes added to point clouds enhanced insights. Especially the RGB point cloud sparked excitement due to its realistic appearance. The Cloud-to-Cloud Distance (C2CD) attribute showed potential, especially for erosion detection. However, due to the short timeframe between measurements, it could not be detected. The NDVI attribute was perceived as less interesting.
The use of explorative point clouds, generated from raw LiDAR point cloud data, offers potential uses and insights for floodplain maintenance. The interdisciplinary value of explorative point clouds was clearly visible. This thesis emphasizes that underused raw LiDAR data, by making it explorative, can act as a valuable resource.","Explorative point cloud; UAV; LiDAR; VR; Floodplain maintenance; NDVI; Change detection","en","master thesis","","","","","","","","","","","","Geomatics","","51.9670881019059, 4.944320457661195"
"uuid:32f2b6ed-cc04-4e7e-ad14-2d7e5fb2dc83","http://resolver.tudelft.nl/uuid:32f2b6ed-cc04-4e7e-ad14-2d7e5fb2dc83","The implementation of adaptability as a tool for future proof buildings in the Netherlands: An action plan for clients to influence the implementation of adaptability in development projects","van der Weijden, Esra (TU Delft Architecture and the Built Environment; TU Delft Management in the Built Environment)","Remøy, H.T. (mentor); de Jong, P. (graduation committee); Delft University of Technology (degree granting institution)","2024","We have to change. We have to take a second look at our daily patterns. The construction sector is responsible for 36% of the world’s final energy use and 39% of energy and process-related carbon dioxide emission (IEA, 2019). 30% of this emission is due to building construction. Therefore, it is important to start to limit the carbon emission from construction processes. An efficient and sustainable way to limit the emissions is to develop buildings that are adaptable to any function or user, with the least effort and minor transformations to the building. Additionally, according to Manewa et al. (2016) buildings are continuously confronted with internal and external environmental changes to which they must respond. Those changes happen unpredictably and with many uncertainties. Buildings that are not able to react to those changes will be prematurely obsoleted, require extensive transformations, or need to be demolished, neither of which will result in a built environment that is sustainable (Manewa et al., 2016). Therefore, by not being able to adapt to the changing society and future demands, we are not building to last.
Even though several strategies have been developed and research has been conducted on the concept of adaptability, the transition from knowledge to implementation seems out of reach. Those studies mainly focus on the implementation of adaptability on the building level and not on the building as a “life cycle process”. Only a number of books and studies also examine the cooperation of the various parties in developing the proposed strategies. From this problem statement, the following research question is formulated: “What are the criteria for developing an adaptable building, and how can clients influence the implementation of these criteria in development projects?”. To answer this question, a literature review is conducted from which a list of adaptability criteria is developed. Additionally, the criteria are compared to existing Dutch cases through a case study with a cross-case analysis, and the roles and influences of parties involved in the development of adaptable buildings are established through interviews. The findings from the empirical research are used to develop an action plan which is validated by an expert panel. The action plan can be used by clients or other stakeholders as a guideline for developing adaptable buildings in the Netherlands. It can also be used to motivate and inspire other stakeholders or to start the discussion about the concept, and develop a more sustainable built environment.","adaptability; future proof; adaptability criteria; action plan; stakeholders; role; influence","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:c8593a67-4657-45ea-aa5a-dd694c88b92c","http://resolver.tudelft.nl/uuid:c8593a67-4657-45ea-aa5a-dd694c88b92c","Collaboration during the energy transition in urban development: An exploratory research of the barriers and enablers for collaboration with an energy network operator in a cross-sector partnership in new urban area development projects","Papenhuijzen, Daan (TU Delft Architecture and the Built Environment; TU Delft Management in the Built Environment)","Hobma, Fred (mentor); van den Bragt, P. (graduation committee); Delft University of Technology (degree granting institution)","2024","The importance of climate change is getting increasingly more attention from all stakeholders in urban development. This results in the energy network operator being increasingly involved in the partnerships needed to realize new urban area development projects. Current projects have been experiencing delays due to the electricity grid not being able to comply with the new increased energy needs. The energy network operator is not used to intensively collaborate in urban development projects. This results in collaboration barriers, resulting in hold-up problems in urban development projects. The ‘boundary spanners’ (the people operating at the boundaries of their organization) experience these collaboration barriers with other stakeholders. With the use of interviews and questionnaires, the experienced collaboration barriers will be identified with the use of the Delphi method. This will enable the prioritization of time and resources. Combined with practical recommendations, the problem of energy network congestion can hopefully be tackled.","energy transition; energy network congestion; urban developments; energy network operator; cross-sector partnerships; boundary spanning; boundary spanner; stakeholder collaboration","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:38c48022-20b5-468f-b026-5d892f569ba2","http://resolver.tudelft.nl/uuid:38c48022-20b5-468f-b026-5d892f569ba2","Degrees of Encounter: Densification Strategies to Alleviate Urban Loneliness in Post-War Neighbourhoods","Hendi, Alaa (TU Delft Architecture and the Built Environment)","Mooij, H.A.F. (mentor); Guis, R.S. (mentor); Eckardt, H.F. (mentor); Delft University of Technology (degree granting institution)","2024","The growing concern about a mental health crisis and a looming threat of the loneliness epidemic worldwide that was further escalated by the COVID-19 pandemic forced people into isolation and created a new form of ‘work from home’ lifestyle. Nonetheless, the loneliness epidemic can be traced back to the 19th-century design principles that designed our current cities with reference to industrial tools such as the car instead of the ‘human scale’. Many of these modernist ideals had negative implications on the mental health of the residents in post-war districts. Moreover, with the need to build more homes, the current housing market values densification strategies that are primarily for profit and not for the needs of the people, which continues the pattern of ‘living together apart’. Consequently, there is an urgency to tackle isolation among the inhabitants of Groot-IJsselmonde, specifically Thamerdijk and post-war neighbourhoods being primarily targeted for future densification schemes. Interventions are therefore required to encourage degrees of social encounter. A research-based approach explored within five different lenses, sociological, historical, urban, building and dwelling scale is translated into a design project that could potentially allow for more positive densification for both current and future residents.","Loneliness; Densification; Housing Crisis; Post-war Architecture; Urban Loneliness; Psychology; Transformation; Co-Housing; Social Housing; Modernism","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Advanced Housing Design","","51.8800169, 4.5490452"
"uuid:82b8a85d-fd03-45a7-a216-771bf2307df9","http://resolver.tudelft.nl/uuid:82b8a85d-fd03-45a7-a216-771bf2307df9","The Remembered City: towards reclaiming a collective ground within Vienna’s inner city","Michl, Maximilian (TU Delft Architecture and the Built Environment)","Rosbottom, D.J. (mentor); Pimlott, Mark (mentor); Mulder, K.B. (graduation committee); Delft University of Technology (degree granting institution)","2024","Based in Vienna, Austria, the project deals with the possibilities a new type of public interior has for a gradually flattened historic city centre, concentrating on the role of derelict spaces such as abandoned shop spaces, aggressively demolished building plots or undervalued topographies in this instance an underground car parking have once integrated back into the grain of the city.
The project proposes a new type of urban institution, a network of rooms, reinterpreting and adapting aspects from typologies that local residents would be familiar with such as the ‘Wiener Kaffeehaus’, the ‘Durchhaus’ or the ‘Bildungsgrätzl’ to create a sequence of spaces and rooms that carry a sense of familiarity and intimacy for the users. Situated in the Ruprechtsviertel, one of Vienna’s most historic but underappreciated neighbourhoods, the project questions the means through which architecture can help appropriate a new public interior and reclaim spaces that are currently underutilised. Through this, it hopes to invite local communities and new publics to reclaim a sense of the qualities the city centre had for communal life all these years and continue its legacy through it.
The comparative literature research identifies two pertinent tools, DuMo and BPSC, both addressing standardization of sustainability and heritage values with distinct methodologies. The analysis of these tools' applicability in practice leads to the second phase of the research, aiming to determine if the core indicators of these tools can facilitate in the decision-making process of church transformation design.
While assessment tools primarily seek to standardize values, this paper explores their potential applications standardization of values can have in the design approach. Although not initially created for the purpose of design, the standardization achieved through these tools can enhance comprehension of various considerations in different stages of the design process. In conclusion, this research contributes to the existing framework on the standardization of heritage and sustainability values, specifically within the context of church transformations in the Netherlands.
This research focuses on understanding how a move for young elderly can be better facilitated to contribute to decreasing the housing crisis. The research explores the desired dwelling characteristics of this demographic and the factors influencing their decision to move. The study adopts a mixed-methods approach, combining quantitative data analysis with qualitative interview insights. The quantitative data makes use of an existing dataset from Woononderzoek Nederland 2021. The interview data is collected by interviewing young elderly.
The findings reveal that the young elderly, primarily residing in owner-occupied dwellings, have diverse characteristics and preferences. While financial stability and higher education position them in the owner-occupied market, their desired dwelling characteristics vary based on age, income, and household composition. A preference for smaller dwellings, particularly apartments, is identified, indicating the potential for increased housing flow if suitable options are available. Factors influencing the decision to move categorised into willingness, ability, and awareness, are explored comprehensively. Health considerations, dwelling type and size, living environment, and social connections emerge as pivotal elements in this decision-making process. The research delves into why and how these factors influence the decision to move, providing valuable insights into the nuanced aspects of young elderly’s decision-making. The research translates these insights into actionable strategies, proposing facilitation methods, including creating push and pull factors, increasing the supply of suitable housing, and raising awareness of available options. The involvement of disinterested organisations, such as Vereniging Eigen Huis, is identified as a potential facilitator, representing the interests of the young elderly in collaboration with policymakers and developers.
In conclusion, this thesis offers a comprehensive understanding of the housing needs and desires of the young elderly in the Netherlands and provides practical facilitation strategies. The findings contribute to a more nuanced and inclusive approach to housing policy, aiming to alleviate the housing crisis through housing flow. Continuous research and adaptive policy-making are emphasised for a sustainable and inclusive housing future. Recommended for further research is to generalise the results using a survey. This research only conducted nine interviews, making generalisability hard. Approaching experts in that field to get their professional views on the subject is also advisable.
Keywords| Young elderly, housing flow, willingness to move, moving behaviour, facilitating a move","Young elderly; housing flow; willingness to move; moving behaviour; facilitating a move","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:861cc976-9e56-488b-bde2-7e26b511fe7a","http://resolver.tudelft.nl/uuid:861cc976-9e56-488b-bde2-7e26b511fe7a","What A Waste: Redefining the Private-, Collective-, and Public Space Towards a Circular System for Food and Consumer Goods in the Domestic Domain","Tulp, Emma (TU Delft Architecture and the Built Environment)","van den Burg, L.P.J. (mentor); Goncalves, J. E. (graduation committee); Delft University of Technology (degree granting institution)","2024","The scarcity of resources is increasing, resulting in the transformation of entire regions. People take a lot of the resources on Earth for granted. This calls for a transition from the current ‘throw-away’-economy to a ‘circular’ economy. The constant circulation of materials and products in this type of system preserves the value of materials. Academics and practitioners are addressing this transition, but they frequently ignore its social and spatial aspects. A socio-spatial framework for reorganizing a district towards a circular system is proposed in this thesis. The solution presented is fundamentally utopian, aiming to challenge established ideas about the current system. In this thesis, the public space’s redesign serves as an entry point to the private and communal spaces.
The design location for this thesis is the Indische Buurt. This district is located in east of Amsterdam. With a large proportion of social housing, the area’s primary use is residential. Additionally, there are a few shopping streets nearby. The approach used in this thesis was context-specific. The three main approaches used were literature reviews, field research, and ‘research by design’.
According to the analysis, residents are crucial in deciding whether and how to dispose of things. But at the moment, the area doesn’t have many resources supporting circular behavior. The issue of waste disposal in public areas is one of the effects. In addition, the district has a high proportion of minima-households, little greenery, and roadways that are mostly occupied by parked cars. The primary observation about governance analysis is the lack of emphasis on the spatial implications necessary for the shift to a circular system.
The district is reorganized using a spatial framework that was constructed using the R-ladder. The R-ladder is a circularity model made up of ten R-strategies for reducing the amount of materials and resources used in product chains. The higher up the strategy is on the ladder, the more value is retained. Following that, a spatial design for a square and its surrounding streets is proposed. The visibility of circularity is prioritized in this design to enhance public awareness. Furthermore, the design aims to maximize the value retention of materials or products by selecting the solution that best retains value. In addition to the design, recommendations will be made to the governance of the Netherlands and Amsterdam. This will improve the existing circular strategy and policy.
This thesis introduces a novel reusable node and beam system for use in the automatic assembly of freeform architecture. By optimising input shapes, applying computational placement of the elements and generating instructions for robotic systems, the building sector can not only improve its productivity and reduce its emissions, it can furthermore revolutionise the stylistic nature of architecture and facilitate the fluid adaptation of new forms and functions.","Freeform architectural surfaces; Robotic Assembly; reuse of building components; automation in built environment; Design for disassembly; Design for Manufacturing; ROS 2; Grasshopper; Robotic automation of construction","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Building Technology","","52.005806,4.370222"
"uuid:37923640-7085-4214-a9d2-cfd352656fd3","http://resolver.tudelft.nl/uuid:37923640-7085-4214-a9d2-cfd352656fd3","The Natural In-Between Place for Stress Relief through Biophilic Design","Rietveld, Masja (TU Delft Architecture and the Built Environment)","Smit, M.J. (mentor); Tillie, Nico (graduation committee); van der Zaag, E.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","We humans evolved in nature, but over the years we moved from being a part of nature to being apart from nature. This causes our mental health, with stress as the most important aspect, to suffer from our modern life in the city. A significant challenge we face is finding ways to integrate nature into our build environment for stress relief. A solution can be found in biophilic design which draws on our biologically ingrained tendency to interact with and experience nature. The problem, however, is that there are already many studies demonstrating the mental health qualities of biophilic designs, but there is not yet a translation for application for the architect. This translation was made within this project by creating a design guide as thesis, concluding with a tool for architects. Then, the TNW building on the TU Delft Campus was used as a prototype, since 97% of students at TU Delft experience stress and this building will become vacant.
To provide stress relief, the renovation design shows a new way of living by investigating the 'natural in-between place', from the user's perception. The natural in-between space is created by first opening the building for natural light and fresh air. Then the landscape flows in and the structure is revalued. This creates a new renovation approach. This renovation approach focuses on showing natural processes for multiple senses, which is the conclusion of the stress relief tool. The natural processes arise from integral interventions of building requirements and an ecologically future-proof landscape. An example is the water system. Rainwater is collected on the retention roof. This water passes through a small waterfall in the natural in-between place to storage. After use, it flows through a helophyte filter. Then it goes to the campus water grid and the water can be reused. In this process, the Mekelpark acts as a seasonal buffer. These natural integral interventions respond to the user perception, for example by providing fresh breaks, more leisure time in quality nature and awareness of natural processes.
The natural in-between place forms the connection between an ecological landscape and student activities such as living, studying, sports and culture. Besides the main ambition theme perception, the following ambition themes are also part of the design: sustainability through awareness of natural processes, climate design, healthy natural and local materials.
In order to sustainably meet this demands and guarantee access to electricity and water for all, new technologies and careful energy planning can play an important role.
In this context, floating solar power is a relatively new technology with promising advantages, such as the synergies between solar and hydropower resources, the exploitation of already existing infrastructures, and the reduction of evaporation rates and land use. These become even more relevant if seen in the context of the Eastern Nile Basin countries, where the need for efficient energy sources and solutions to the water scarcity issues are vital.
In this work, the role of floating solar power in the sustainable fulfillment of the increasing energy demand of the region is explored. The novelty of this study consist in the introduction of floating solar power in a long term regional energy system cost-optimization model (OSeMOSYS-TEMBA) at a single plant resolution. To do so, the single hydropower plants are also explicitly modelled, allowing both the spatial disaggregation of floating solar power plants and the connectivity between the countries via the Nile river. The regional approach is further enhanced by the presence of electricity trade links between countries, which connect the energy systems of the single countries directly.
Finally, the role of floating solar power on the energy system's footprints is evaluated in terms of CO2 emissions, land use and water savings. To this extent, a new methodology for land use accounting and pricing is proposed, and findings from previous studies are brought together to assess the evaporation reduction rates caused by the floating solar power plants.
This extended modelling framework is then used to analyse different scenarios, exploring hydrological regimes under different climate change projections and policy decisions such as the introduction of taxes for carbon emissions and land use change.
The results show that floating solar photovoltaics are a cost-optimal technology since early stages in the modelling horizon, and their full assumed potential is developed under every scenario. Their role in satisfying the energy demand of the whole region reaches 3\% of the generation mix in the reference scenario, but it increases to 4.3\% with the introduction of taxes on carbon emissions and land use. Moreover, the introduction of such policies cause an anticipation of floating solar power's capacity expansion. On the other hand, the tested climate change projections do not affect the results relevantly.
The sensitivity analyses, however, prove that the obtained results are very sensitive to the assumptions behind capacity constraints and costs of these technologies, which need more dedicated research.
As far as the energy system's footprints are concerned, the results show that the implementation of floating solar power can help reduce the total emissions and land use slightly, and cause evaporation reduction rates up to 376 million m\textsuperscript{3}/y (approximately 2\% of the total evaporation from hydropower reservoirs).
The optimal locations to invest in this technology are identified to be the largest hydropower plants in the system (Lake Nasser, the Grand Ethiopian Renaissance Dam and Merowe reservoir), but the reason of this choice relies in the very large size of these plants, which emerge for highest
FPV capacity deployment and water evaporation savings at the large scales considered.
Future research is still needed to reduce the uncertainty behind the key parameters (costs, capacity constraints), improve the representation of hydropower production, improve the evaporation assessments and investigate the effects of implementing floating solar power at smaller spatial and temporal scales.","Energy planning; Floating solar power; Hydropower","en","master thesis","","","","","","","","2025-01-26","","","","Water Resources Engineering","",""
"uuid:69ffd9a5-7b07-4197-b295-f2e37620de30","http://resolver.tudelft.nl/uuid:69ffd9a5-7b07-4197-b295-f2e37620de30","An analysis of the transformation potential of office buildings in The Hague","Espinal, Liz (TU Delft Architecture and the Built Environment)","Remøy, H.T. (mentor); de Jong, P. (graduation committee); Pronk, Sjoerd (graduation committee); Delft University of Technology (degree granting institution)","2024","Sufficient housing supply is one of the most significant issues in the Dutch housing market. The Dutch government aims to realise 15.000 dwellings a year by transforming vacant commercial real estate. However, a discrepancy can be noted between the number of buildings that developers have been willing to transform in the past decade and what the Dutch government deems feasible regarding the transformation of commercial real estate going into the future - a transformation dip. Next to that, office buildings with an energy label worse than C are not allowed to be used as office buildings anymore in 2023 unless they are renovated. This forms an interesting starting point as building owners are required to reassess the potential of the building and choose between different strategies, such as transformation, to prolong the lifespan. Thus, the goal of this thesis is to explore possibilities for bridging the gap between the number of buildings transformed annually on a national scale and the public transformation goals by applying a tool-the Conversion Meter- which aims to locate potential buildings in a city and asses their conversion potential. The Dutch city of The Hague is chosen as a case to apply this method, and the office stock with an energy label worse than C is chosen for the population. The following research question is answered during this thesis: To what extent can the number of office-to-housing conversions in the Netherlands be increased to meet the public goal of realising 15.000 dwellings through transformation a year? Buildings were selected out of an online real estate database using a set of preselected filters- office building in The Hague, with a minimum size of 3000m², not a listed monument and an energy label worse than C. 26 buildings were analysed, and it was determined that approximately 43% of the buildings analysed have a transformation potential based on the results of the Conversion Meter (9 out of 21 buildings-5 buildings discounted) and approximately 29% was deemed to have transformation potential based on the results of the Conversion Meter and the discussions with the expert panel (6 out of 21 buildings). In The Hague, more buildings could be found if smaller buildings are assessed too, as most of the buildings predicted to become economically obsolete (buildings energy label G) are smaller than 500m². Next to that, the normative approach of the Conversion Meter now discriminates against buildings in business parks due to a lack of facilities and location. However, as cities expand, some business parks have become engulfed by the city. The Binckhorst in The Hague is an example of a business park that will be transformed into a mixed-use area where buildings are found. Areas like these in cities provide great opportunities for adding more dwellings through transformation.","Adaptive reuse; The Hague; Transformation potential; Office buildings; Energetic performance","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:50e2609e-644d-4241-b3f2-a17f204d2c06","http://resolver.tudelft.nl/uuid:50e2609e-644d-4241-b3f2-a17f204d2c06","Spatial Height Prediction of ICESat-2 Data using Random Forest Regression","Kan, Leo (TU Delft Architecture and the Built Environment)","Ledoux, H. (mentor); Pronk, Maarten (graduation committee); Rafiee, Azarakhsh (graduation committee); de Wolff, H.W. (graduation committee); Delft University of Technology (degree granting institution)","2024","The Earth's surface is a complex landscape that is essential for a wide range of applications, from urban planning to environmental monitoring. Digital models of the Earth's surface are generated through mathematical calculations using elevation data collected from various sources and the Digital Terrain Model (DTM) which captures the bare earth's surface topography in 2.5D. The creation of DTM is an approximation of terrain in unsample locations, by using x-y coordinates and one z value. Traditionally, terrain interpolation uses deterministic or geo-statistical methods to calculate elevation. This research would use random forest regression as an alternative method and to compare the results against traditional interpolation. Comparing different locations against traditional interpolation yields similar results overall. Feature importance, within the the points that are closest to the sampled ICESat-2 data point are more significant than other features used in Random Forest model. The correlation between these datasets and the spatial relationship established would impact on the results of the elevation. The improvement overall of using traditional interpolation compared to random forest regression is limited depending on the location and using model trained with local datasets. For model trained on other geographical locations, which shows similar differences.","ICESat-2; Interpolation; Digital Terrain Model; Random Forest; Topography","en","master thesis","","","","","","","","","","","","Geomatics","",""
"uuid:f6158c21-a06a-4cc2-9c32-587cd91f04f6","http://resolver.tudelft.nl/uuid:f6158c21-a06a-4cc2-9c32-587cd91f04f6","Envisioning the future of study places: Lessons learned from the general educational buildings at TU Delft","Tangelder, Laura (TU Delft Architecture and the Built Environment)","den Heijer, A.C. (mentor); Gramsbergen, E.H. (graduation committee); Delft University of Technology (degree granting institution)","2024","This thesis examines how TU Delft could adapt its study places in generic educational buildings to meet current and future demands. This research is done through a literature review and an examination of three
representative cases at TU Delft and in-depth, semi-structured interviews.
Despite the expectations of a pandemic-induced shift to online learning, this research emphasises the continued significance of a high-quality on-campus environment. Findings reveal a surplus of study places, urging qualitative enhancements, especially in aspects like community feeling.
Future prospects suggest a move towards interdisciplinary learning, requiring a diverse mix of study places. Recommendations encompass effective scheduling and smart campus tools, redefining quality parameters for study places, and creating adaptive learning environments. The findings advocate for a balanced approach, accommodating both quiet, focused study places and dynamic, socially engaging meeting places.
In conclusion, TU Delft is advised to holistically adapt study places, integrating quantitative and qualitative insights, as detailed in the lessons learned from the general educational buildings.
“PLAN B: Future waterscapes” is a utopian vision, building upon the agenda of LOLA LANDSCAPE ARCHITECTS, where we expand the city beyond the dikes. A central tower is introduced, intended for use as both a water reservoir and for residential purposes, inspired by the Indus civilization. Thanks to the flexible and sustainable structure of this building, it can expand along the dike, adding a new urban fabric to the historical city of Delft.
The research process involved thorough analysis of interview results which led to dilemmas which offered a base to the ideation process employed within this project. Through ideation and iteration, a creative solution could be generated that holds promise for fostering human flourishing. In lines with the principles of Positive Design, this condition is key for enhancing subjective well-being and offers an insight on the potential of design to contributing to this within the domain of gardening.
Prior to the field research, extensive desk research and a literature review was conducted, where the existing sources between well-being and gardening were explored. Additionally, the role of gardening tools within the aspect of how they contribute to well-being was explored, given the collaborative nature of this project with the company Talen Tools, renowned for its high quality gardening tool craftsmanship.
As a final result, this project offers a new perspective on how designers can harness Dilemma-Driven Design to actively contribute to Positive Design, embodied through the design of the “PocketHelp”, a device that aims to overcome the dilemma of desiring help from fellow gardeners without seeming helpless, which is a dilemma commonly faced by community gardeners within the gardening complex Delftse Hout. The project offers insights into various design strategies which can be utilized to the enhancement of subjective well-being, in this case particularly within the context of communal gardening.","dilemmas; well-being; design; Gardening; tools","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:6a3ae5a1-abb9-4d5c-91de-859f7e32c5e2","http://resolver.tudelft.nl/uuid:6a3ae5a1-abb9-4d5c-91de-859f7e32c5e2","How to maintain or enhance a sense of community in post-war neighborhoods, which are going through regeneration process","Gerstenkorn, Ella (TU Delft Architecture and the Built Environment)","Mooij, H.A.F. (mentor); Eckardt, H.F. (graduation committee); Guis, R.S. (mentor); Delft University of Technology (degree granting institution)","2024","In this research, I strived to explore solutions to the question:
How to maintain or enhance a sense of community in post-war neighborhoods undergoing regeneration processes
The outcome of this research provides a guideline for architectural planning, in creating an environment that reflects the importance of a sense of community in the built environment. The outcome can be viewed as a manual for analyzing and retrofitting neighborhoods, focusing on the shared spaces and maintaining or enhancing a sense of community. By focusing on a specific site, and examining its characteristics, I formed a guideline on how to treat specific issues with architectural interventions. I examined theories by various researchers (such as Gehl, Whyte, David Sim, and Bernard Tschumi) as well as architectural drawings of master plans that focus on shared spaces as an integral part of the vision.
To the plans of the municipality the sex workers out of the area have reacted with the message: “don’t save us, save our windows”, a note that is revealing how the area is dealing with a material and social problem at once. This message is also very relatable to this research, since I will be approaching it through the window. The architectural element of the window has an high symbolic value and reveals a lot about societal norms and values. Therefore, to explain a wide range of developments that took place over the last two centuries, this research begins with examanining historical photographs that display the windows of sex workers and are carefully analyzed through hand drawings. These studies will be supported by theoretical resources which elaborate on prevailing societal norms and values that concerned sexuality.
What this research will illustrate is how sex work is often concerned with moral questions, like the issue of (female) body determination. As a result, sex work became a familiar topic within histocial feminist debates, having either a liberative or oppressive effect on the profession. Since the goal for this research is to imagine the future of sex work spaces in the Wallen area, it will navigate through these debates in order to take a position in the contemporary feminist debate myself. Hoping to find a appropriate design approach which will challenge the strategy of the municipality.","Sex Work; the Wallen; Feminism; Window; Visibility","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Explorelab","",""
"uuid:ca6976fe-c1a0-4aa2-89b2-662ba4212e6e","http://resolver.tudelft.nl/uuid:ca6976fe-c1a0-4aa2-89b2-662ba4212e6e","Designing a semi-automated approach to find potential evidence of corporate greenwashing","Bindi, Ludovica (TU Delft Technology, Policy and Management)","Goyal, N. (mentor); Ghorbani, Amineh (graduation committee); Zhang, J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Greenwashing can be defined as the mismatch between companies’ positive green communications and their activities that are counterproductive to the fight against climate change. Greenwashing companies can undermine the success of climate policies by hiding their climate footprints and prevent policymakers from realizing the need for further regulations. Thus, the identification of greenwashing should be done timely: this research sets out to find a semi-automated approach that can find evidence of greenwashing. The study of greenwashing is limited to the mismatch between companies’ communications on official websites and their lobbying activities in the European Union. Some steps of the design research approach were used namely the design development, demonstration, and evaluation (via a small-case evaluation) phases. The created approach measures companies’ communication levels of commitment to climate change using a GPT-based sentence classifier and then compares it to their levels of lobbying on climate change using keyword-based filtering on the EU Transparency Register, the official lobbying source for the EU. The proposed method is semi-automated at this stage and can inform a greenwashing appraisal, but it has issues with the accuracy of its analysis. This research partially fills the gaps in the greenwashing literature and advances the research in the use of GPT for classification purposes and in the field of climate lobbying in the EU. This research can teach the implementation of new EU regulations that aim at banning greenwashing: the more detailed the definitions of greenwashing that are used, the easier to find greenwashing automatically, and, therefore, the faster the enforcement of the ban can be.","greenwashing; Design research; automation; corporate communication; lobbying; corporations; deductive coding; EU Transparency Register","en","master thesis","","","","","","https://github.com/LudovicaBindi/collecting_greenwashing_evidence.git GitHub repository that contains the data collected, used, and produced for this thesis.","","","","","","Engineering and Policy Analysis","",""
"uuid:385a63dd-fe8f-4091-9cbf-2984a02bdb85","http://resolver.tudelft.nl/uuid:385a63dd-fe8f-4091-9cbf-2984a02bdb85","IAmHOME: Transforming an existing house into a smart house to provide for the well-being of its residents","Balakina, Lena (TU Delft Architecture and the Built Environment)","Așut, Serdar (mentor); Khademi, S. (mentor); Delft University of Technology (degree granting institution)","2024","This thesis investigates the transition of traditional houses into Smart Homes, emphasizing the improvement of residents’ well-being, particularly for those aged 50 to 60. It is set against the rapid growth of Smart Home Devices enabled by the Internet of Things, facilitating easy control and monitoring of home features. There has been a significant increase in the market, with global shipments of such devices rising by 12% in 2021, reflecting a trend towards more connected and automated homes.
Smart Homes are becoming increasingly popular with people spending more time at home and the rise in digitalization. These homes represent technology and address the needs of an aging population, energy efficiency, and personal well-being enhancement. Yet, this shift to digital comes with challenges, including reliance on the internet and potential cybersecurity risks. The dissertation critically reviews these issues and looks at possibilities applied in the Built Environment.
Approaching the integration of Artificial Intelligence in the Built Environment, the study delves into the evolution from Smart Homes to Intelligent Homes. In this transition, AI plays a crucial role in creating environments that are adaptive and capable of making predictions. This shift towards more advanced technology raises important issues regarding privacy, ethical implications, and finding the right balance between convenience and security.
The research is driven by a detailed problem statement emphasizing the urgent need for innovative housing solutions in light of an aging society and healthcare system pressures. The case study developed in this thesis is in the Netherlands, where projections suggest that by 2035, over 24% of the population will be 65 and above. The study aims to transform an existing house into a Smart Home, focusing on improving indoor climate and resident well-being. Recognizing the subjective nature of health and well-being, it notes that the advantages of a Smart Home can differ among individuals. The study is significant for its potential contribution to the development of assistive technologies and services, ultimately seeking to improve life quality and support aging in place for future generations. With a combination of interdisciplinary fields such as Architecture and the Built Environment, design, and Artificial Intelligence, this thesis explored the possibilities for the future by taking a computational approach, including focusing on the indoor environment, comfort, and other things related to the technical aspect of the building.
According to Galema & Van Hoogstraten (2005), the shopping centres built in 1940-1965 according to contemporary and recent literature are often hardly recognisable, due to the speed at which commercial attitudes change. They further state that retail is forced to keep up with the times, and retail buildings and centres change regularly. Concluding that the building type evades traditional monument conservation.
This is despite forming an essential part of neighbourhoods for their socioeconomic value (Robertson & Fennell, 2007; Kooijman, 1999; Feinberg et al., 1989).
Therefore, the research focuses on determining who the insider stakeholders are and how they value the spatial attributes of a changed 20th-century shopping mall. One of the key strategies for the survival of a 20th-century mall is to reinvent its meaning in contemporary society.
The design focused on how to incorporate these values combined with contemporary design theories such as Gehl, and Sim, among others.","Heritage & architecture; Shopping mall; stakeholders; insiders; Interview","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Heritage & Architecture","","52.03711489835971, 4.3151787087021765"
"uuid:145406d8-353f-4091-866e-fad69c771c8c","http://resolver.tudelft.nl/uuid:145406d8-353f-4091-866e-fad69c771c8c","Redefining Schooling: Co-crafting a Community Waterscape for the Bajau Laut","Sarra, Christina (TU Delft Architecture and the Built Environment)","Chan, P.W.C. (mentor); van de Pas, R.R.J. (mentor); van de Voort, J.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","The Bajau Laut or Sama Dilaut people are an ethnic group of sea nomads who used to roam between the Filipino, Malaysian, and Indonesian maritime zones. The Bajau are known to be amazing freedivers, being able to dive in depths of up to 30 meters and having the ability to hold their breath for more than 5 minutes, making them a group of people that biologically adapted into an amphibious lifestyle.
In 1877, most present-day Sabah, Malaysia, was surrendered to the newly constituted British North Borneo Chartered Company. The reforms constituted by the Company gradually forced them to self-build the first pile house setlements in 1955 and abandon nomadism for a sedentary lifestyle along the shore in 1979. Due to their nomadic lifestyle in the past, none of the three SE Asian countries have recognized the community as indigenous people, making them stateless and hence depriving them of the right to civil registry, subsidized healthcare and education with the exception of Alternative Learning centers that are run by NGOs and volunteering teachers. However, what is the position of Alternative Learning Centers regarding indigenous educaon and the importance of school as an establishment?
Alternative learning centers offer basic literacy classes such as Malay language and Mathematics. Still, volunteering, uncertified teachers have the freedom to improvise by introducing classes related to their major or the children’s wishes. However, only a small part of the curriculum has anything to do with the community’s traditional ecological knowledge or identity.
How do we define literacy nowadays? What deems a person illiterate? This project aims to redefine schooling by introducing a culturally responsive curriculum in a community waterscape that acts as a mediator between the community's built environment and the surrounding marine landscape, prioritizing knowledge stemming from both environments.","SE Asia; sea level; Bamboo; Indigenous community; Traditional ecologcal knowledge; Nomadic; local building culture; Local materials; Low Tech; School; School architecture","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Explorelab","","4.4908499313248935, 118.60211674822584"
"uuid:bd56e08b-5445-4e7c-9bde-044ec81c68be","http://resolver.tudelft.nl/uuid:bd56e08b-5445-4e7c-9bde-044ec81c68be","Towards Zero Carbon: A Comprehensive Evaluation of Conventional Renovation Strategies for Terraced Houses, Using Life Cycle Analysis (LCA) and Life Cycle Costing (LCC) to Enhance Decision-Making Support – accompanied by the design of a tool: Support for short term and long term decision-making in renovation","Sewnath, Madevi (TU Delft Architecture and the Built Environment)","Konstantinou, T. (mentor); Broersma, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","To reduce global warming the emission of greenhouse gases (GHG) must be net zero in 2050, Paris agreement. In the Netherlands the building sector is responsible for 38% of total GHG emissions, 27% being operational carbon (related to energy use) and 11% embodied carbon (related to the use of materials). A large portion of the GHG emissions in this sector originates from existing residential buildings and is for the majority related to energy for heating.
Renovating existing buildings is a key step in reducing operational carbon emissions related to heating. Due to the environmental advantages of renovation, it acts as the first step to reduce carbon emissions. The general strategy to reduce carbon emissions, first focuses on the operational carbon by transitioning from non-renewable depletable energy sources to renewable, sustainable energy sources, also known as the energy transition, starting with replacing natural gas for heating and cooking. In the Netherlands the target is to reduce 49% of GHG emissions compared to 1990 by 2030, and 95% by 2050. In practical terms this requires a renovation of 1.5 million residential buildings by 2030 and 5.5 million residential buildings by 2050.
As operational carbon decreases, reducing the embodied carbon becomes more important. Unlike operational carbon which is only present during the in-use stage of a building, the embodied carbon is present in all stages of a building’s life cycle. Clear standards on the assessment of carbon emissions over the full life cycle of a building are missing. Due to this current strategies are not selected to reduce carbon emissions on the complete spectrum of carbon emissions. The risk is that the overall carbon reduction of the building stock is less than expected.
Renovation changes the life cycle of a building and thus its long term performance. Renovations with high energy saving often can’t be performed in a single step due to high investment costs. Therefore renovation is often executed in multiple steps. Understanding the effects of different use-phase scenarios can help reduce carbon emissions on the long term.
Furthermore, assessing the performance of all generated renovation solutions, at an early design stage, can be time consuming and requires a high level of information. This limits the number of renovation options explored and indirectly influences the effectiveness of a renovation.
The aim of this thesis is to investigate how assessment of renovation strategies can be simplified to support decision making in renovation. The thesis investigates different renovation strategies and scenarios for the in use stage of a terraced house, to improve decision/making in renovation, by looking at the level of renovation, renovation measures, renovation execution and decision making criteria. The data gathered is used to create a tool, supporting decision-making for renovation strategies. Data is obtained using various tools, and by performing among others a simplified Life cycle analysis (LCA) and life cycle costs (LCC) assessment. The performance of the renovation strategies are evaluated based on energy performance, environmental performance and costs.
Despite progress, gaps persist in understanding SoSEAL’s influence on sand’s mechanical properties, particularly on the shear strength. The primary objective in this research was to investigate the impact of different concentrations of Al-OM (Aluminum and Organic Matter) flocs on sand’s mechanical characteristics through ex-situ mixing. This included the development of a testing procedure using a triaxial test apparatus, incorporating results from permeability tests and utilizing microscopy to analyze micro structural changes and the underlying mechanisms. The study aimed to deliver valuable insights into SoSEAL’s potential as a nature-inspired geo-engineering solution for soil improvement.
Undrained triaxial tests were conducted on ex-situ mixed sand with different concentrations of Al-OM flocs, namely 0, 0.1, 0.5 and 1%. These concentrations were defined as dry mass of flocs based on a metal/carbon ratio of 0.06. Through a carefully executed test procedure, involving Proctor’s test, permeability measurements and triaxial testing, the mechanical properties of the treated sand were investigated. Proctor’s tests were utilized to determine the maximum dry density and its corresponding moisture content of the (un)treated sand. These parameters were used for molding the sand samples for the triaxial test series. The untreated sand did not show a clear peak in its Proctor curve, which is typical for uniform graded fine/medium sands. The porosities, derived from the optimum dry density and corresponding water content, were found to be ≈ 0.4 (-) for all samples. Indicating the minor impact of the Al-OM flocs to the porosity of the sand samples.
The undrained consolidated triaxial test procedure, consisting of saturation, consolidation, and shearing, provided insights into the mechanical properties of SoSEAL. Although the consolidation phase did not reveal significant differences
in the presence of Al-OM flocs, elastic parameters, derived from the shearing phase, generally increased with higher Al-OM floc concentrations in sand. Young’s Modulus, E , increased by a magnitude between 2.11-2.62 times the untreated sand, while the shear Modulus, G, increased by a magnitude between 2.09-2.18. Nonetheless, exceptions such as test CU05-1 and CU10-2 were observed. Strength parameters, measured by maximum deviatoric stress at failure, exhibited an overall increase with higher floc concentrations. Finally, the results show that an alteration in floc concentration in sand did not have a significant impact on its permeability, contrary to previous measurements obtained in the absence of confinement.
The results from the Proctor’s test, permeability measurements and the triaxial tests highlighted differences and improved general knowledge of the impact of Al-OM flocs to the mechanical properties of sand. Variations in test results, seen
when comparing test CU05-1 to CU05-2 and test CU10-1 to CU10-2, underscored the complexity of factors such as compaction challenges and localized failures. From microscale examination using scanning electron miscroscopy (SEM), the increase in strength properties can be attributed to the cohesion between sand grains, evident in the formation of grain clusters. As the concentration of Al-OM flocs in sands increased, so did the quantity of grain clusters. The potential of Al-OM flocs in sand for dyke improvement is found in the observed increase in elastic and strength properties, providing enhanced resistance against erosion.
A common limitation often encountered in transport datasets is class imbalance, with regard to the utilization of the different modes. Class imbalance in this context refers to the uneven distribution of samples among the various modes. Modes with a higher number of samples are termed majority modes, while those with fewer instances are labeled as minority modes. The existence of class imbalance within the dataset has the potential to compromise the performance of classifiers, especially for the minority modes, leading to inaccurate forecasts. This, in turn, may result in insufficient investments and provisions for these modes, ultimately having adverse consequences for the population segments that rely on them. Existing studies in the literature have either entirely overlooked or only partially addressed the impact of class imbalance. Recognizing the significance of precise demand predictions and acknowledging the identified gaps within the literature, the primary research question of this study revolves around systematically identifying and addressing the impact of class imbalance in mode choice forecasting.
To address the main question, a framework was proposed. This framework encompassed various aspects including a) the measurement of class imbalance within a dataset and the assessment of its impact on classification performance, b) the investigation of other challenging factors coexisting in imbalanced datasets, with a specific focus on class overlap, and c) the proper evaluation of classification performance across classes. As an integral part of this framework, the 'Performance Gap Metric’ was introduced - a metric employed to evaluate the difference in classification performance between the majority and minority classes. Establishing a threshold of 20%, favorable classifier performance was determined when this metric fell below the threshold, signifying the classifier’s equitable treatment of both minority and majority classes. Subsequently, this framework was applied using the ODiN data as a case study to predict mode choices in the Netherlands. Mode choices encompassed car, bike, and transit, with car representing the majority and transit the minority class. Two modeling techniques, namely Random Forest and an MNL model, were employed in conjunction with various sampling techniques, including the SMOTENC, the Neighborhood-based Undersampling, and the Separation scheme...","","en","master thesis","","","","","","","","","","","","Engineering and Policy Analysis","","52.2129919, 5.2793703"
"uuid:5e3d7f14-d5b9-4dfe-9277-e2634be47611","http://resolver.tudelft.nl/uuid:5e3d7f14-d5b9-4dfe-9277-e2634be47611","Climate Impact Assessment of Sustainable Aviation Fuels: A scenario based assessment of the climate impact of sustainable aviation fuels in the year 2125","Koopdonk, Pieter (TU Delft Aerospace Engineering)","Yin, F. (mentor); Delft University of Technology (degree granting institution)","2024","","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:77cb99e6-6fbf-4d9e-a744-76a50aa552fa","http://resolver.tudelft.nl/uuid:77cb99e6-6fbf-4d9e-a744-76a50aa552fa","Anomaly Detection in Sleep Staging in Critically Ill Children","Oerlemans, Carlijn (TU Delft Mechanical, Maritime and Materials Engineering)","Tax, D.M.J. (mentor); de Jonge, R.C.J. (mentor); Kuiper, Jan Willem (mentor); Joosten, K.F.M. (graduation committee); van Twist, Eris (graduation committee); Delft University of Technology (degree granting institution); Erasmus Universiteit Rotterdam (degree granting institution); Universiteit Leiden (degree granting institution)","2024","Study objectives: Conventional sleep scoring is based on the scoring criteria of the American Association of Sleep Medicine (AASM) but may not be suited to describe sleep in critically ill children admitted to the Pediatric Intensive Care Unit (PICU). In this study, an anomaly detection model using Gaussian Models trained on sleep stages in data from non-critically ill children is developed to assess if polysomnography(PSG)-derived electroencephalography (EEG) data from critically ill children can be categorized into sleep stages based on these AASM scoring criteria.
Methods: A retrospective study at Erasmus MC Sophia Children’s Hospital, using PSG recordings obtained in non-critically ill children between 2017 and 2021 and in critically ill children between 2020 and 2022.
Gaussian Models were individually trained for each sleep stage using data from non-critically ill children. Anomaly detection was carried out by computing the Mahalanobis Distances and assigning datapoints to specific sleep stages or categorizing them as anomalous. Errors were quantified by calculating the ratio of anomalous epochs to the total number of epochs. The trained Gaussian Models were applied to distinct sleep stages in the data from non-critically ill children. Subsequently, the models were applied to data from critically ill children to determine the categorization of their epochs. This was also analyzed over time and involved comparisons related to medication, mechanical ventilation, and the severity of illness assessed by the PELOD-2 score.
Results: In non-critically ill children the models obtained validation errors aligning with the margin error of the training set. The models could not fully differentiate the distinct sleep stages. In critically ill children, the majority of epochs were classified into multiple sleep stages. High error rates were evident for sleep stages N1, R, and N. Some patients exhibited elevated error rates specifically for sleep stage N1. REM sleep was reduced, consistent with findings from previous studies. In contrast, N3 sleep did not show a reduction. When compared to the sleep stage labels assigned by neurophysiologists, the model classified epochs into multiple sleep stages, while neurophysiologists frequently used the label N. A higher PELOD-2 score did not consistently correlate with an increased occurrence of anomalous classifications in the epochs of these patients to those with lower PELOD-2 scores.
Discussion: Overlap of sleep stages was observed in non-critically ill children. Epochs from critically ill children were classified into multiple sleep stages without clear associations in time or severity of illness. Building upon the established anomaly detection framework is recommended by employing more advanced anomaly detection methods using an informative feature selection. This study marks an initial step, indicating that applying the AASM.","Pediatric intensive care unit; Anomaly Detection; EEG; Sleep","en","master thesis","","","","","","","","","","","","Technical Medicine | Sensing and Stimulation","TM30004; 35 ECTS",""
"uuid:3cf9e4cb-05e2-41d2-afa1-a8400be50e07","http://resolver.tudelft.nl/uuid:3cf9e4cb-05e2-41d2-afa1-a8400be50e07","Revolutionizing airline catering trolley transport by using a Unit Load Device","Wempe, Joost (TU Delft Mechanical, Maritime and Materials Engineering)","Jovanova, J. (graduation committee); van den Bos, W. (mentor); Rietveld, Egbert (mentor); Delft University of Technology (degree granting institution)","2024","The increasing automation in various industries has underscored a notable gap in the airline catering sector, where predominant manual transport of airline catering trolleys within facilities results in substantial costs and physical strain. This paper addresses these challenges by proposing an automated solution for the transport logistics of airline catering trolleys within catering facilities.
The suggested solution involves implementing a Unit Load Device (ULD) designed to securely carry multiple airline catering trolleys. This ULD is engineered for compatibility with various transport systems, including Automated Guided Vehicles, highloaders and conveyors.
The paper outlines the design process for a ULD within an airline catering facility. To formulate a comprehensive design, several design problems are identified, and potential solutions are presented. Subsequently, multiple viable load plate prototypes are constructed and tested on an Automated Guided Vehicle and highloader, resulting in the identification of a single viable all-purpose ULD for the entire process. Additionally, an in-house ULD emerges as a cost-effective alternative to the all-purpose ULD.
In this context, this paper introduces a comparative analysis of three possible future airline catering facilities: utilizing 1 ULD, using 2 ULDs, and employing no ULDs (or maintaining the current status quo). The comparison reveals minimal cost differences between facilities employing 1 or 2 ULDs, both facilities however show significantly more cost efficient compared to using no ULDs.","ULD Design; Airline Catering Facility; Dual ULD configuration; Inclined ULD Design","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:5fb0dfe6-94cc-40f1-8773-91367b5e2fba","http://resolver.tudelft.nl/uuid:5fb0dfe6-94cc-40f1-8773-91367b5e2fba","Analysis and Design of Lens Antenna Systems for Applications at Millimeter and Sub-millimeter Wavelengths","Zhang, H. (TU Delft Tera-Hertz Sensing)","Llombart, Nuria (promotor); Neto, A. (promotor); Delft University of Technology (degree granting institution)","2024","In recent decades, dielectric lens antennas have been more and more adopted and developed for sensing and imaging applications at sub-millimeter (sub-mm) wavelengths because they can achieve high gain while keeping their physical size and weight acceptable at these wavelengths. More recently, as low-loss and low-cost lens materials have become available and the lens fabrication is becoming easier and more accurate, lens antennas are attracting more interests for variety of applications at millimeter (mm) wavelengths such as high-data-rate wireless communication and automotive radars. However, the analysis and design of lens antennas at mm and sub-mm wavelengths present different challenges. In this thesis, we propose to use a field correlation technique to analyze lens antennas in reception and then optimize their aperture efficiency for different scenarios. Based on this optimization methodology, three examples of lens antenna systems are described at 28 GHz, 180 GHz, and beyond 200 GHz for the applications of 5G communication, wide field-of-view security imaging, and future mm-resolution THz imaging, respectively. The proposed methodology and design provide possible solutions for the potential challenges and can be used as guidelines for designing lens antennas at mm and sub-mm wavelengths.....","Equivalent circuits; focal plane arrays; field correlation; geometrical optics; lens antennas; leaky-wave antennas; lens shaping; millimeter waves; photoconductive antennas; quasi-optical systems; sub-millimeter waves; sparse array; time-domain analysis; ultra wideband; wide field-of-view","en","doctoral thesis","","978-94-6384-524-3","","","","","","","","","Tera-Hertz Sensing","","",""
"uuid:04e4fe71-d257-4cac-aaa6-56390b3d80f9","http://resolver.tudelft.nl/uuid:04e4fe71-d257-4cac-aaa6-56390b3d80f9","Analysis of the slow-moving landslides in the Mazar Region in southeast Ecuador","Urgilez Vinueza, A.R. (TU Delft Water Resources)","Bakker, M. (promotor); Bogaard, T.A. (promotor); Delft University of Technology (degree granting institution)","2024","Landslide activity in the Andes remains an ongoing natural hazard with significant implications for regional development. Slow-moving landslides, while not typically resulting in catastrophic outcomes, can still cause substantial damage to critical infrastructure, including roads, buildings, crops, and hydropower dams. In southeast Ecuador, slow-moving landslides threaten the stability and functionality of theMazar damand reservoir. This thesis aimed to address these challenges by characterizing the slow-moving landslides in theMazar region and developing a systematic approach to identify changes in their displacement rates, understand their physical causes and assess the influence of hydrometeorological forcings.....","Slow-moving landslides; Hydro-geology; Hydro-Meteorology; Accelerations-decelerations; Multiple regression","en","doctoral thesis","","978-94-6384-526-7","","","","","","","","","Water Resources","","",""
"uuid:0f8d81ac-8171-4ede-9d01-3cd6cda6aff6","http://resolver.tudelft.nl/uuid:0f8d81ac-8171-4ede-9d01-3cd6cda6aff6","An incentive to wander: The case of the Leyweg","Naaktgeboren, Daphne (TU Delft Architecture and the Built Environment)","Meijers, W.L.E.C. (mentor); Meijer, A.S.C. (mentor); Quist, W.J. (mentor); Marulo, F. (mentor); Delft University of Technology (degree granting institution)","2024","In the Netherlands, shopping centres are abun¬dant. Whether they are large-scale malls or small neighbourhood centres, they are woven into the fabric of Dutch society. But recently and in the future many malls will be facing the prospect of vacancy. A response therefore is needed. This design was created for the Leyweg in the Hague, and exemplary neighbourhood mall of the Netherlands. The design is focused on the social sustainability of a mall, a future proof design that could be applied to the many small scale shopping malls in the Netherlands. It is designed as a centre in the neighbourhood for people to come together, to meet each other, not solely as an incentive to seduce people to buy as much as possible. By bringing multiple functions in the mix, such as dance, study, work and community spaces, the mall becomes an centre point for the vicinity and attracts a large, diverse audience. It is made for people to just simply be there, to explore, to bring an incentive to wander.","Post-war Shopping mall; 20th century heritage; Leyweg Winkelcentrum; mixed functions; comfort; spatiality; inclusivity","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Heritage & Architecture","","52.049895, 4.275352"
"uuid:f66c4807-48d4-4046-af4a-536a0afc5192","http://resolver.tudelft.nl/uuid:f66c4807-48d4-4046-af4a-536a0afc5192","Grow With the Flow: Developing a Dynamic Coastal Interface for the Wadden Sea Region","van den Boomen, Venne (TU Delft Architecture and the Built Environment)","Nijhuis, S. (mentor); van der Veen, R.J. (graduation committee); Reinders, L.G.A.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","We live in a world of constant change, driven by human activities that have had an unprecedented impact on our planet’s geology and ecosystems, fundamentally reshaping environments worldwide. Coastal environments, with their complex land-sea, human-nature interactions, are among the most fragile and are constantly under the influence of natural and human processes. For decades, these processes moved in harmony, but as populations grew, so did the demand for resources, land and the development of infrastructure, such as dams, dikes, transport networks and coastal management interventions. The fixation of coastlines and inland systems, driven by contemporary artificial human activity, is an often unintended consequence.
The Wadden Sea Region, known for its extensive mudflats, salt marshes and diverse flora and fauna, is an example of how human intervention has had a significant impact on the form and systems of the transition zone between sea and land, or the coastal interface. Over thousands of years, the region has been shaped by the interaction of sea, land and human influences, resulting in a gradient of vital coastal habitats for numerous species and providing many ecosystem services for local and (inter)national economic prosperity. In recent decades, however, human interventions have increasingly altered the region’s coastal interface, largely disrupting the dynamic exchange of energy and materials through land reclamation and infrastructure development. The separation of land and sea has resulted in the loss of the gradual gradients that were once a defining feature of the Wadden Sea Region, along with the region’s identity of ‘living with water’. This has meant the additional loss of vital habitats and ecosystem services provided by the sea for decades, and the overall loss of socio-ecological resilience of the interface system. Now, with the increasing pressures of climate change and human needs on the complex system of the Wadden Sea region, its landscape faces serious challenges now and in the future. A new balance needs to be found between human activities and the conservation and restoration of the unique natural and cultural values of the Wadden Sea Region.
The research aims to explore the potential of a new interface framework that restores the landscape gradient between land and sea in harmony with natural processes and cultural values. The intention is to increase the overall social and ecological resilience of the interface system through the development of landscape-based design principles and design interventions, which will be tested at different temporal and spatial scales. The northern Netherlands will serve as a regional test-bed for innovative forms of production and living along the future interface, where the proposed design layout is based on analysis of coastal geomorphological processes, historical practices, landscape structures and existing water structures.","Wadden Sea Region; Coastal interface; Resilience; Landscape-based Approach; Landscape framework; Landscape Architecture","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Landscape Architecture","","53.3833318, 6.1833326"
"uuid:bd9a6840-9c69-43a3-9720-730d5879d4b6","http://resolver.tudelft.nl/uuid:bd9a6840-9c69-43a3-9720-730d5879d4b6","Developing places for human capabilities: Understanding how social sustainability goals are governed into urban development projects","Janssen, C. (TU Delft Practice Chair Urban Area Development)","Verdaas, J.C. (promotor); Daamen, T.A. (copromotor); Delft University of Technology (degree granting institution)","2024","Although social objectives are frequently part of the pursuit of sustainable urban development, how such social sustainability goals can be achieved in urban development practices remains a largely unsolved puzzle. While scholars increasingly acknowledge that urban social sustainability is a plural concept that needs to be specified in different situations, thus far very few social sustainability studies have focused on the processes in which such specifications take place – i.e., the implementation processes in which policies are brought into practice in urban areas or neighborhoods. This dissertation develops an understanding of how institutionalized governance processes affect the implementation of policy goals related to social sustainability in area-based urban development projects. The research draws on Sen’s Capability Approach (CA) to construct a capability-centered evaluation of such efforts. More than other normative approaches that primarily focus on the distribution or quality of spatial goods, the principles of the CA focus on the fact that different people have different experiences. Unique personal, social, and environmental circumstances per individual imply that people have different capabilities: the actual freedoms to do or be what one considers valuable for a dignified life. A promising role is reserved for the CA to investigate how exactly the diversity of human beings can be incorporated into urban development and planning processes. This provides a sincere response to the calls of social sustainability scholars that more ‘human-centered’ approaches are needed. The dissertation hypothesizes that governance processes around urban development projects hold various elements that affect the implementation of social sustainability in contemporary cities, and subsequently, influence whether ‘capability-centered urban outcomes’ are achieved or not. In that way, this dissertation analyzes how governance processes in urban development practice relate to capability-centered evaluations of urban social sustainability outcomes. Whereas these two aspects are often investigated separately – i.e., studies often either focus on analyzing the mechanisms within governance processes or on describing and evaluating social outcomes in the urban environment – this dissertation explicitly brings these together. The governance process is investigated from a collaborative governance perspective to analyze which activities and interactions between the different stakeholders affect capability-centered social sustainability outcomes in urban environments, and complementary, from an institutionalist perspective that explores what less-visible, yet structural elements of governance condition the emergence of capability-centered governance activities.","social sustainability; urban development projects; collaborative governance; institutions; capability approach","en","doctoral thesis","A+BE | Architecture and the Built Environment","978-94-6366-799-9","","","","","","","","","Practice Chair Urban Area Development","","",""
"uuid:6c933d63-6c9b-4e1d-b660-12fd1fe45c3f","http://resolver.tudelft.nl/uuid:6c933d63-6c9b-4e1d-b660-12fd1fe45c3f","Mitigation of Hydropeaking in a Complex Riverine System: A State-of-the-Art Modelling Approach: A quantitative study with HEC-RAS modelling on hydropeaking by means of a case study in the Kalajoki basin (northern Finland)","Moonen, Siirilotta (TU Delft Civil Engineering & Geosciences; TU Delft Hydraulic Engineering)","Wüthrich, Davide (mentor); Marttila, H. (graduation committee); Sloff, C.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Hydropeaking is a widely applied management practice in the generation of hydropower. When the demand in electricity is high, the operator of a hydropower plant rapidly increases released discharges to meet this demand. Vice versa, when the demand is low, no or less water is released. However, while river regulation practices offer valuable resources, they can also inflict adverse environmental consequences on downstream river segments. More specifically, hydropeaking introduces high sub-daily variance in downstream reaches of the hydropower plant. This large sub-daily variance is harmful to the river regime and ecosystems. In Finland, hydropeaking has the highest negative environmental impact of all river regulation practices. The most prominent, known negative impacts due to high flow variations are a direct impact on aquatic biota, such as trout, and a compromised recreational use of the river corridor. The main objective of the thesis research is to investigate the impact of hydropeaking on rapids in a complex riverine system. More precisely, a system that includes multiple subsequent weirs, vegetation, large riverine boulders, a rather flat topography and a small-scale anabranch. Additionally, related to the modelling approach, two state-of-the-art calibration methods and their benefits and limitations are discussed. The formulation of operational and morphological mitigation measures to counter impacts is the secondary objective. A case study for the downstream region of Hamari Hydropower Plant at Ylivieska (Finland), the site Juurikoski, provides insight on the different aspects related to these queries. During a series of simulation runs, including the original situation and three hypothetical mitigation scenarios, the impact of hydropeaking is quantified and studied. Results include post-processed water level, velocity and shear stress data. Furthermore, conclusions and a discussion are given regarding the potential of calibration and validation for a 2D hydrodynamical model by state-of-the-art methods. These methods refer to a hot spot analysis comparison based on LSPIV-data and velocity profile comparisons based on ADCP-data. On a local scale, mitigation recommendations are suggested or excluded from a practical point of view. From a more global perspective, the report provides a modelling approach to tailor mitigation measures according to riverine lay-out, despite limited bathymetry data and increased riverine complexity.","river regulation; hydropeaking; environmental impact; calibration; ADCP; LSPIV; Kalajoki; Finland; Weir; 2D; hydraulic modelling; HEC-RAS; mitigation measures","en","master thesis","","","","","","","","","","","","Civil Engineering | Hydraulic Engineering","","64.07487, 24.53668"
"uuid:52f8da3e-a3be-4f02-a53b-74d66107686b","http://resolver.tudelft.nl/uuid:52f8da3e-a3be-4f02-a53b-74d66107686b","UAV Swarm Intelligence in CEMA: Enhancing Urban Communication Line Management","Holman, Storm (TU Delft Aerospace Engineering)","Sharpanskykh, Alexei (mentor); Delft University of Technology (degree granting institution)","2024","In response to the increasing challenges of Cyber Electromagnetic Activities (CEMA) in urban settings, characterized by dense electromagnetic (EM) signals and rising data traffic, this research introduces an Agent-Based Model (ABM) aimed at prioritizing critical signals. The primary goal of this research is to deploy a Unmanned Aerial Vehicle (UAV) swarm operating to selectively interfere with communication lines in a CEMA environment. The research goal is segmented into a multi-stage approach, focusing on the following mission tasks for the UAV swarm: i) Transmitter Search, ii) Communication Line Search, iii) Communication Line Mapping, and iv) Interference Point Finding. This research proposes and evaluates various methodologies for these task. A methodological contribution is the development of the Heuristicdriven Utility by Regression-based Metrics Synthesis (HURMS) framework. This framework addresses the subswarming coalition formation problem in Multi Transmitter Search. The HURMS framework utilizes the benchmarking Monte Carlo Tree Search (MCTS), a heuristic search method, to enhance the Maximum Utility Configuration (MUC), a transparent utility-based method, overcoming heuristic search limitations and complexities in creating utility functions. While the HURMS-enhanced MUC method effectively located all transmitters in the task, comparative analysis showed MCTS to be about 45% faster and 56-71% more successful in transmitter detection. This highlights potential areas for enhancing the MUC algorithm further under the guidance of the HURMS framework. Furthermore, the Particle Swarm Optimization (PSO) Search was utilized as a velocity controller in the context of Multi Transmitter Search methods, guiding the speed and direction of UAVs. Regarding Single Transmitter Search, a significant observation was that the PSO Search was approximately 38% faster than the novel Pair-gradient Search method in locating a single transmitter. The study also examines Communication Line Mapping by comparing two frontier-based methods with the Multi-agent Tabular Q-Learning method. The frontier-based methods provided better coverage, while the Tabular Q-Learning excelled in precision and adaptability for multi-agent mapping. Data from these methods were applied to find the interference point. Additionally, a Reinforcement Learning (RL)-trained agent was used for Interference Point Finding, proving to be faster but less accurate.","Swarm intelligence; UAV; CEMA; ABM; Reinforcement Learning; MCTS; Coalitions Formation; PSO","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:16c3c3d6-ff76-463c-871b-749fa92a4243","http://resolver.tudelft.nl/uuid:16c3c3d6-ff76-463c-871b-749fa92a4243","From Risk to Resilience: A Strategic Procurement Approach to Risk Mitigation in the Supply Chain: Leveraging Supplier Relationship Management and Multi-Criteria Decision-Making for Risk Mitigation","Vaandrager, Celine (TU Delft Technology, Policy and Management)","Rezaei, J. (mentor); Roosenboom-Kwee, Z. (mentor); Scharff, R. (mentor); Delft University of Technology (degree granting institution)","2024","This thesis addresses the increasing vulnerabilities in modern supply chains, particularly within the maritime industry. Emphasizing the crucial role of procurement in risk mitigation, the study challenges conventional lean management, advocating for agile supply chain strategies. It introduces the Integrated Supplier Matrix (ISM) to enhance supplier segmentation, combining aspects of the Purchasing Portfolio Matrix (PPM) and Supplier Potential Matrix (SPM).
Conducted as a case study at Allseas, the research employs the Best Worst Method (BWM) to rank risks, identifying the uniqueness of the product, rules and regulations, and external factors as significant concerns. Through graphical representations and ISM-based supplier segmentation, relationships between supplier willingness, capabilities, risks and profit impact are established. The findings stress the importance of communication and trust in supplier relationship management (SRM) trade-offs, including inventory reliance, contract durations, sourcing strategies, and addressing non-performing suppliers.
The research provides insights for maritime managers, recommending the integration of theoretical SRM approaches with multi-criteria decision-making methods for resilient supply chains. The suggested shift from lean to agile management and the ISM implementation offers practical strategies to optimize relationships, navigate complexities, and establish adaptive procurement approaches, effectively mitigating supply chain risks.","Supply Chain Management; Risk mitigation; Supply chain resilience; Supplier Relationship Management; Multi-criteria decision-making; Best Worst Method; Maritime Industry","en","master thesis","","","","","","","","2024-12-28","","","","Management of Technology (MoT)","",""
"uuid:a636d8de-ebdc-4835-81b7-f3fa81dc74e9","http://resolver.tudelft.nl/uuid:a636d8de-ebdc-4835-81b7-f3fa81dc74e9","An Optimised Approach to Wireless Power Transfer for an Artificial Retina Implant","Wijermars, Ronald (TU Delft Electrical Engineering, Mathematics and Computer Science)","Muratore, D.G. (mentor); Delft University of Technology (degree granting institution)","2024","An artificial retina can replace some of the functionality of the eye in people that have experienced partial or complete loss of vision. Loss of vision is associated with many negative effects in one’s life and can be a debilitating condition. Artificial retinas in the form of a chip thus offer the potential to greatly improve people’s lives.
A wireless implementation is much preferred to the wired alternative, as it reduces the risks associated with implantable devices while also being less invasive to the patient. Wirelessly powering an artificial retina implant requires careful consideration of the impact on tissue heating as this is the fundamental
limit in how much power an implantable device can consume.
This thesis provides an optimal implementation of wireless power transfer in the framework of an artificial retina implant with the explicit goal of reducing tissue heating. A literature study forms the basis for identifying the key metrics and providing a switched capacitor power converter (SCPC) topology needed to realise the final system performance. The key innovations are a first-of-its-kind design of an ctive rectifier, a novel system-level optimisation and an SCPC to implement the o ptimised system approach while simultaneously enabling a novel, efficient, low-overhead closed-loop control of the link. It was shown that a 30 % reduction in radiated power can be realised for a given system while maintaining the same output load power. The designed active rectifier can achieve orders of magnitude faster settling compared to the state of the art, allowing rapid amplitude-shift keyed data transfer to be employed on the wireless power transfer link. The active rectifier achieves a simulated voltage conversion ratio of 92.0 % and a power conversion efficiency of 90.1 % for a 500 Ω load. an SCPC as designed and fabricated to achieve a load transformation to the calculated optimum load. A simulated 80 % efficiency at a power density of 29 mW/mm2 was achieved, with a conversion range of 0.7 − 1.8. Measurement results proved to be inconclusive. The SCPC was shown not to work and the active rectifier’s performance couldn’t be precisely verified. An improved measurement setup and additional debugging options in the chip design are among the proposed improvements for future work.","WPT; Switched Capacitor; SCPC; Active Rectifier","en","master thesis","","","","","","","","2026-01-12","","","","Electrical Engineering | Microelectronics","",""
"uuid:fa782171-a22c-4675-844a-72b6358f1f7f","http://resolver.tudelft.nl/uuid:fa782171-a22c-4675-844a-72b6358f1f7f","Experimental Design of a Solar-Heated Water Displacement Pump","Strecht Ribeiro Hipólito Reis, José (TU Delft Industrial Design Engineering)","Ghodrat, S. (mentor); Alferink, J.R. (graduation committee); Delft University of Technology (degree granting institution)","2024","The report at hand is a comprehensive summary of the conducted research and consequent developments in the experimental design of a solar-heated water displacement pump focused on its implementation in areas lacking access to safe drinking water, particularly in developing countries.
The research begins by examining the dire situation faced by the two billion people lacking safely managed drinking water (WHO/UNICEF JMP, 2023). This is done by looking closer at the factors influencing water supply, considering needs and the context in which these affected people live.
This contextual analysis motivated the need to develop a solar-powered water pump system designed to effectively, reliably and sustainably bring safe drinking water from improved water sources to households in the most affected regions of the world.
To address this need, existing pumping systems that are currently used or have the potential to mitigate this problem were studied and evaluated.
By carefully examining the most recent advancements in relevant water pumping technologies for this contextual application, an innovative opportunity for converting low-grade heat energy into mechanical energy was identified.
Having identified the problem and understood its context, analysed the existing solutions and identified a potentially disruptive hypothesis, an innovative system of an affordable, robust, and scalable solar-heated water displacement pump was designed.
In addition, the design was validated with a high-fidelity prototype with which experiments were done to successfully prove the concept’s working principle.
The successful proof of concept aligns with the established objectives of simplicity and accessibility. In fact, the water pump prototype was created on a minimal budget, making use of simple and accessible tools and materials, highlighting its potential for scalable cost-effective manufacturing.
This report provides a comprehensive analysis of the performance of the prototype, along with the theoretical design considerations that influenced its development. As a result, it serves as an experimental logbook that also offers insights into the existing water crisis and contributes to a better understanding of it. Thus, the present work lays the foundation for future research and developments on this innovative working principle, making it a valuable contribution to this life-changing field.","Solar Water Pump; Global Access to Safe Drinking Water; Sustainable Development Goal 6","en","master thesis","","","","","","","","2026-01-05","","","","Integrated Product Design","",""
"uuid:1851c698-5367-411e-8d30-703c8e1ebb1e","http://resolver.tudelft.nl/uuid:1851c698-5367-411e-8d30-703c8e1ebb1e","An Experimental investigation into the drag performance of chevron-shaped protrusions in a turbulent channel flow: Experimental investigation into the drag and one dimensional velocity statistics","Schilder, Jop (TU Delft Aerospace Engineering)","Schrijer, F.F.J. (mentor); Baars, W.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Contrary to conventional wisdom favouring smooth surfaces for drag reduction, the last decades have brought forth different textured surfaces showing drag reduction in turbulent boundary layers, of which riblets are the most studied.
Sirovich and Karlson (1997) introduced a different textured surface named chevron-shaped protrusions, indicating a drag reduction of 10% in turbulent channel flows.
Later studies questioned their efficacy as no credible reproduction of the results was obtained throughout the years.
The last credible reproduction study by Carrasco Grau et al. (2023) suggested that the reasons for this discrepancy could reside in the difference in model and test section size.
All reproduction studies were performed in facilities with external boundary layers instead of internal and with a covered area no longer than 0.8 meters, instead of the 8-meter-long channel flow which was fully covered in these chevrons from the original study.
This work will investigate just that, using a channel flow facility with dimensions more akin to that used by Sirovich and a model size of 2.4 meters.
The study assembles and characterises an improved channel flow facility with dimensions identical to those used by tay et al. (2011) at the National University of Singapore (NUS), measuring a total length of eight meters and a test section of 2.4 meters.
This facility used an array of 29 static pressure taps to determine the skin friction via the mean pressure gradient method, and utilised hot wire measurements in the midpoint of the test section for investigation of the flow mechanics of the chevrons.
The measurements performed on a flat plate were compared to the results obtained at the NUS to characterise the facility and validate its suitability for single-point drag measurements in the order of 5-10% increase or decrease.
Once this was confirmed the different configurations of chevron-shaped protrusions were investigated.
The key findings of this study are twofold.
Firstly, the developed channel flow facility at DUT proves proficient in generating canonical boundary layer profiles, enabling accurate skin friction measurements of textured surfaces.
The facility provides good hot-wire measurements without sensor vibrations capable of investigating the boundary layer characteristics in this facility.
Secondly, the study establishes that chevron-shaped protrusions are likely unsuited for reducing turbulent skin friction in turbulent channel flows.
Despite an inability to definitively disprove the working hypothesis, the observed increase in drag suggests that the technique's efficacy is not determined by the facility type and model size.
It is not considered worthwhile to conduct additional research into chevron-shaped protrusions as a potential technique for reducing drag in turbulent boundary layers.
However, the minimal drag penalty associated with this technique opens new possibilities for the application of this technique in the aviation sector, mainly in aiding with separation control and heat transfer.","Turbulenct boundary layers; Drag reduction; Chevron-shaped protrusions; Channel flow","en","master thesis","","","","","","","","2026-01-12","","","","Aerospace Engineering","",""
"uuid:d8d7f2a0-d1ba-46b6-affd-c2903a527fc1","http://resolver.tudelft.nl/uuid:d8d7f2a0-d1ba-46b6-affd-c2903a527fc1","Incorporating Bird Strike Crashworthiness Requirements within an MDO Framework","Ciobotia, Ioana (TU Delft Aerospace Engineering; TU Delft Aerospace Structures & Materials)","Castro, Saullo G.P. (mentor); Peeters, D.M.J. (mentor); van der Laan, A.H. (mentor); Zarouchas, D. (graduation committee); Chen, B. Y. (graduation committee); Delft University of Technology (degree granting institution)","2024","The present study, which was carried out in collaboration with GKN Fokker, focuses on incorporating bird strike crashworthiness requirements within a multidisciplinary optimization (MDO) framework. During the preceding three-month internship in the same company, a pivotal contribution to this project was the development of an Abaqus interface for the Multidisciplinary Modeller, MDM, created within the Center of Competence in Design department. MDM is a Python/ParaPy-based automated generator of wings, moveables and flaps, starting from a set of user-specified parameters. The generation of ready-to-run input files thus lays the foundation for the subsequent optimization process, as any changes in materials or geometry can be easily accommodated.
The core objective of the research is to minimize the weight of an aircraft wing while taking into account additional requirements related to the extent of damage caused by bird strikes. Unfortunately, such events occur more frequently than one would be comfortable with, and stringent requirements are set in place to guarantee the safety of the passengers. Among these requirements, the aircraft must be capable of landing safely after such an event, being subject to loads associated with get-home conditions.
As a consequence, two critical constraints are formulated within the optimization framework, addressing the residual strength of the damaged front spar following a bird strike, coupled with a requirement based on a maximum penetration depth. The last constraint has also been included due to the rising popularity of the electric vertical take-off and landing aircraft, which not only fly at low altitudes, thus increasing the risk of bird strike, but may also contain battery packs in the leading edge, for instance, which can pose a significant risk if damaged. To tackle the complexity of this highly-dimensional optimization challenge, a methodology based on Bayesian optimization is proposed, employing surrogate models coupled with a preliminary variable ranking procedure.
The Kriging metamodel is identified as a suitable candidate, thanks to its error prediction capabilities, which are paramount in Bayesian optimization. A variance-based dimensionality reduction method is proposed, which makes use of an initial surrogate to estimate the main and interaction effects of the variables. The quantification of the significance of a variable is expressed as its percentage contribution to the total variance, thus allowing for an intuitive selection of the most important parameters. After the screening procedure is complete, the optimization procedure is carried out in the reduced design space, which uses the constrained expected improvement as an acquisition function. The proposed methodology is then applied on a case study problem, involving a five-bay metallic wing segment subject to the constraints aforementioned, involving 19 design variables representing the thicknesses of various components.
Remarkable weight savings have been achieved, the final result being 40\% lighter than the lightest feasible design among the initial data points. A significant dimensional reduction has also been attained for the maximum depth constraint, which is expected due to the local nature of the impact. Not only did the number of variables greatly decrease from 19 to just 3, but a considerable increase in the accuracy of the corresponding metamodel has also been registered, thanks to an increase in sampling density in the reduced space. However, the variable screening procedure revealed intricate interaction effects with respect to the residual strength of the front spar, emphasizing the nuanced complexity inherent in crashworthiness considerations. Nevertheless, a moderate dimensional reduction has been achieved for this constraint as well, reducing the number of variables to 8, thus proving the efficacy of the proposed variable screening procedure.
In conclusion, the utilization of Kriging models, variable ranking procedures, and Bayesian optimization collectively contributed to the success of achieving remarkable weight savings, proving the efficiency of the proposed methodology. Moreover, it has been shown that the integration of a residual strength requirement is necessary, as many cases were uncovered where no significant penetration occurred, although the application of the considered load case, which is not from critical to an undamaged wing, resulted in high stresses to the front spar of the damaged structure.","Bird strike; Crashworthiness; MDO; Bayesian optimization; Kriging; Variable screening","en","master thesis","","","","","","","","2026-01-12","","","","Aerospace Engineering | Structures and Materials","",""
"uuid:fbd0d066-6404-459a-b55c-9e191dfcf225","http://resolver.tudelft.nl/uuid:fbd0d066-6404-459a-b55c-9e191dfcf225","Intention Aware Routing System with Variable Station Pricing","de Britto Heemskerk, Roderick (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Discrete Mathematics and Optimization)","van Essen, J.T. (mentor); Fokkink, R.J. (graduation committee); Delft University of Technology (degree granting institution)","2024","Intention aware routing system is a route-planning algorithm for electric vehicles that minimizes overall travel time by taking into consideration congestion at charging stations. This thesis extends this algorithm to allow choices to be made based on prices at charging stations. The goal of this thesis is to find a way to minimize maximum congestion while maximizing overall profit across the stations. To achieve this an optimal price has to be calculated. To this end, a formula is devised and applied to several graphs.","Route planning; Game Theory; Nash Equilibria","en","bachelor thesis","","","","","","","","","","","","Computer Science","",""
"uuid:b12fd20b-2431-46f1-ad1f-e657ed7f4bad","http://resolver.tudelft.nl/uuid:b12fd20b-2431-46f1-ad1f-e657ed7f4bad","Reliability Based Design Optimization on Quay Walls by re-calculating partial factors","Zakynthinos, Petros (TU Delft Civil Engineering & Geosciences)","Flessati, L. (mentor); Kementzetzidis, E. (mentor); Roubos, A.A. (mentor); van den Eijnden, A.P. (mentor); Habets, C.J.W. (mentor); Delft University of Technology (degree granting institution)","2024","In the years to come, the Netherlands will face a substantial challenge as over 1,500 kilometers of aging quay walls and sheet pile walls approach the end of their technical lifespan. Infrastructure managers anticipate that the necessary replacements will necessitate investments amounting to billions of euros. Moreover, this task carries a significant environmental footprint, notably in terms of CO2 emissions. The construction work required for these replacements will also result in disruptions and reduced accessibility, inconveniencing users.
This study addresses two pivotal aspects. Firstly, it focuses on enhancing the design aspects of new structures and optimizing costs, with a specific focus exploring how these enhancements can ease the financial challenges faced by infrastructure managers. Secondly, it investigates the safety of existing structures and explores ways to maximize their loadbearing capacity while maintaining safety standards. The expected outcomes of this study promise improved design aspects, cost-efficiency, and enhanced safety measures.
Quay walls can fail due to various mechanisms. This research investigates three primary causes: yielding of soil, yielding of quay wall and anchor yielding. Quay walls illustrate the complexities of soil-structure interaction. To address this, models were developed in both Plaxis and D-Sheet Piling. D-Sheet Piling was the preferred choice due to its computational speed. The reliability analysis was conducted with Probabilistic Toolkit. Considering the calculation methods, First Order Reliability Method (FORM) was employed, emphasizing in efficient computational results in contrast to the Monte-Carlo approach.
In the first aspect, the partial factors were recalculated and compared them with the existing EC partial factor approach. To optimize the current design methodology, the retaining height of the structure was adjusted based on its reliability index. Additionally, the maximum anchor force required was re-evaluated for the structure. This procedure has been conducted for two scenarios, considering and not considering model uncertainty.
Furthermore, an analysis was conducted to understand how altering the retaining height can lead to reduced steel usage, subsequently impacting costs and CO2 emissions. In the second aspect, it was pursued to enhance the structure’s performance by introducing a factor ""n"" across four distinct scenarios: 1. Simultaneously increasing all loads. 2. Increasing the surcharge loads on the terrain. 3. Increasing the bollard load. 4. Raising the final excavation level in front of the quay wall. While this study aligns with the extensive body of research in the field of civil engineering, It seeks to offer a new and sustainable approach on understanding quay wall design, focusing specifically on the designers’ viewpoint. Through the exploration of innovative design frameworks and approaches, this research seeks to make a valuable contribution to the long-term sustainability of quay wall structures. It aims to redefine our approach to accessibility and safety in these crucial structures. The comprehensive investigations conducted throughout this study provide an enhanced comprehension of quay wall design, reliability, and the optimization of performance.","Quay walls; Reliability analysis; Probabilistic design; Partial safety factors; First order reliability method","en","master thesis","","","","","","","","","","","","Geo-Engineering","",""
"uuid:08ec22da-7f2c-4b9e-b384-87389086b8ba","http://resolver.tudelft.nl/uuid:08ec22da-7f2c-4b9e-b384-87389086b8ba","Strategic Development for the Port of St. Eustatius: A Study on the Potential Role of Privatisation","van Muiden, Thomas (TU Delft Civil Engineering & Geosciences)","van Wee, G.P. (mentor); Annema, J.A. (graduation committee); Vleugel, J (graduation committee); Delft University of Technology (degree granting institution)","2024","This paper examines the potential for privatising the port of St. Eustatius to achieve self-sustainability through the strategic port planning process. Design criteria were established based on a PESTEL, SWOT, and trend analysis, resulting in the development of four strategies. These strategies include enhancing port resilience, creating a transshipment hub, accommodating cruise ships, and enabling the docking of recreational vessels. Based on the strategies, opportunities for privatisation were identified according to the different rationales. Within the different strategies, opportunities for privatisation and a corresponding adaptation of the administrative model are possible. However, the need for large infrastructure investments could hinder the willingness of private parties to invest. Therefore, a public-private partnership is seen as a possible alternative to share the financial risks and also enable the government to retain control.","Strategic Port Planning Process; Privatisation; St. Eustatius; port administrative models; SWOT; PESTEL","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:821f6252-03fb-4a0f-9978-8ac4f8b59bc1","http://resolver.tudelft.nl/uuid:821f6252-03fb-4a0f-9978-8ac4f8b59bc1","An Experimental Assessment of the Stability of Graph Contrastive Learning","Sebus, Siert (TU Delft Electrical Engineering, Mathematics and Computer Science)","Jamali-Rad, H. (mentor); Isufi, E. (mentor); Delft University of Technology (degree granting institution)","2024","The Deep Neural Network (DNN) has become a widely popular machine learning architecture thanks to its ability to learn complex behaviors from data. Standard learning strategies for DNNs however rely on the availability of large, labeled datasets. Self-Supervised Learning (SSL) is a style of learning that allows models to also use unlabeled data for training, which is typically much more abundant.
SSL is being applied many different data domains such as images and natural language. One such a domain is the domain of graph data. A graph is a data structure describing a network of nodes connected by edges. Graphs are a natural way of presenting many forms of data such as molecules, social networks, and 3D meshes.
The style of SSL that has found the most success on graphs is Contrastive Learning (CL). In CL, an encoder is trained to produce semantically rich representations from unlabeled input data by smartly separating task-relevant information in the input from task-irrelevant information. The encoder backbone most commonly used for Graph Contrastive Learning (GCL) is the Graph Convolutional Neural Network (GCNN).
While GCNNs are the state of the art on many graph data tasks, they suffer from underfitting when made too deep. This is especially a problem for GCL as it prevents encoder complexity to scale with the large availability of unlabeled data.
In this thesis, we investigate this underfitting behavior through the lens of GCNN stability. Stability refers to a model's ability to continue producing consistent outputs, even when its inputs are perturbed slightly. Theoretical work has shown that stability guarantees for GCNNs weaken when their complexity is increased. We confirm experimentally that, in many cases, GCNNs indeed grow less stable when made more complex. This a relevant finding given that learning stable representations is a prerequisite to CL. Additionally, we show in our experiments that, even when trained using CL, stability discrepancies between different GCNN architectures do not disappear. This, in turn, suggests that GCNN architectures with poorer stability may also produce poorer representations. We confirm experimentally that, on at least one dataset, poor stability as a result of architectural complexity can indeed be correlated to a degradation in representation quality.
With this result we provide an additional explanation as to why deeper GCNNs are often found to perform worse in GCL settings. These insights can, in turn, motivate the design of model architectures for GCL that do not suffer from this trade-off between complexity and representation quality.","Deep Learning; Contrastive Learning; Graphs; Stability; Self-supervised Learning; Graph Neural Networks; Graph Convolutional Neural Networks","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:8b483b8b-d1cd-4983-8198-fde756114a8a","http://resolver.tudelft.nl/uuid:8b483b8b-d1cd-4983-8198-fde756114a8a","Analysis of engineering wake model validation and calibration with historical data from OWEZ wind farm","Keim, Julienne (TU Delft Mechanical, Maritime and Materials Engineering)","Delft University of Technology (degree granting institution)","2024","Wind turbines are often placed together in wind farms for economic considerations. This causes wake interactions between turbines, resulting in significant power losses. Models that predict these wake losses are critical for estimating wind farm power output and developing strategies to mitigate the wake effect, such as wind farm control. For these applications, engineering wake models are favoured for their computational efficiency. Hence, the validation and improvement of these models is an ongoing area of research. Currently, consensus on the accuracy of engineering wake models is absent in the literature. Existing studies employ varying validation strategies that impact the perceived model accuracy. Furthermore, proposed model improvements often lack quantitative evaluation, limiting the generalisability of the results. Additionally, the potential benefits of calibrating wake model parameters are recognised, yet research on calibration methods and the impact thereof is limited.
This thesis addresses this scientific gap by proposing a holistic framework for the validation and calibration of engineering wake models. The framework combines best practices from literature. First, it accounts for wind direction uncertainty in historical wind farm data. Additionally, it corrects model inputs by including heterogeneous inflow wind speeds. Finally, it offers a methodology for parameter calibration to improve the model's accuracy using historical wind farm data. The overarching framework employs both quantitative and qualitative validation methods to mitigate the impact of experiment design and enable a thorough evaluation of model improvements. The effectiveness of this framework is demonstrated through a case study with SCADA data from OWEZ wind farm and four engineering wake models from the popular control-oriented wake modelling tool FLORIS.
Results show that wind direction uncertainty in SCADA d|ata must be included when validating wake models for specific wind directions or sectors. Additionally, incorporating heterogeneous inflow wind speeds reduced the absolute turbine error by up to 20%. Furthermore, it is demonstrated that calibrating model parameters significantly improves model accuracy. The resulting error reductions reach up to 92% for individual turbines and 65% at farm-level, i.e., for all turbines collectively. Furthermore, results revealed that while the performance of the different models converges post-calibration, differences persist in various scenarios with numerous wake interactions. In these cases, the CC and TurbOPark models outperform the Jensen and GCH models.
Through this holistic framework and the demonstrated potential of model parameter calibration, a path forward is paved for further model improvement in a systematic and quantitative manner.
for minimizing rolling losses on different road surfaces at varying speeds.","rolling resistance; rolling Impedance; total rolling losses; road conditions; bicycle tire; contact patch","en","master thesis","","","","","","","","2026-01-11","","","","Biomedical Engineering | Neuromusculoskeletal Biomechanics","",""
"uuid:2dd874e6-bb94-4e3d-848d-3b54a0bc856a","http://resolver.tudelft.nl/uuid:2dd874e6-bb94-4e3d-848d-3b54a0bc856a","Hydrodynamics for the integration of fermentation and separation in the production of diesel and jet biofuels","Sousa Pires da Costa Basto, R.M. (TU Delft BT/Bioprocess Engineering)","van der Wielen, L.A.M. (promotor); Mudde, R.F. (promotor); Delft University of Technology (degree granting institution)","2024","Over the years, various technologies have been developed to produce and separate advanced biomolecules. These technologies range from complex terpenoids for pharmaceuticals and flavors to commodity chemicals and fuels via the fermentative route. These compounds are often poorly water soluble, phase splitting organic compounds or inhibitory and unstable necessitating addition of an extractive, second liquid phase for product removal. The turbulent conditions in the multiphasic fermentation coupled with the presence of surface-active compounds in the medium create a stable emulsion that is difficult to separate in conventional systems. Technologies such as centrifugation and de-emulsifiers have been used to separate the emulsion and recover the product. However, these type of recovery processes are expensive, drastically increase the final product’s environmental footprint and often hamper cell recycling.","","en","doctoral thesis","","978-94-6483-631-8","","","","","","","","","BT/Bioprocess Engineering","","",""
"uuid:6abb764c-a884-4da9-9f89-7140ee8b097b","http://resolver.tudelft.nl/uuid:6abb764c-a884-4da9-9f89-7140ee8b097b","Dynamics of the Pitch-able VAWT: A Study of the Dynamics of the Vertical Axis Wind Turbine with Individual Pitch Control","LeBlanc, B.P. (TU Delft Wind Energy)","van Bussel, G.J.W. (promotor); Ferreira, Carlos (promotor); Delft University of Technology (degree granting institution)","2024","Society is finally entering a new age of renewable energy development. For the first time it is truly conceivable to power a vast majority of global energy use with a combination of wind, solar, and other forms of low carbon, renewable power. The rise of electrification and so called ”Power to X”, where renewable energy is used to create other more condensed and potentially storable sustainable fuels, will require a significant increase in the capacity of electrical grid networks worldwide in the coming decades. One of the largest growing sectors in renewable energy is offshore wind power. With farms in operation for over two decades, offshore wind has been predominately deployed in relatively shallow water in the North Sea of Europe. While expanding to global markets is possible with fixed bottom machines, the resource is relatively limited based on the strict seabed requirements. Moving to floating offshore wind platforms, demonstrated in pilot projects like Hywind Scotland, has the potential to vastly expand the potential wind resource and open markets in the Americas and Asia which would otherwise be unreachable....","Vertical Axis Wind Turbine; Pitch Control; PIV; Wake Steering; Structural Dynamics","en","doctoral thesis","","","","","","","","","","","Wind Energy","","",""
"uuid:b8088705-62f6-450c-b23e-99e41870a763","http://resolver.tudelft.nl/uuid:b8088705-62f6-450c-b23e-99e41870a763","Tuning dynamics and dissipation dilution in 2D material resonators by MEMS-induced tension","Wopereis, Michiel (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Precision and Microsystems Engineering; TU Delft Dynamics of Micro and Nano Systems)","Steeneken, P.G. (mentor); Verbiest, G.J. (mentor); Alijani, F. (mentor); Staufer, U. (graduation committee); Vollebregt, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","Nanomechanical resonators made of two-dimensional (2D) materials are the subject of intensive research due to their remarkable properties, allowing them to operate at high frequencies with high sensitivity. However, dissipation losses and manufacturing issues have prevented them from reaching their full potential. This thesis aims to overcome these challenges by dry-transferring 2D materials onto a MEMS and clamping them using electron beam-induced deposition. By in-plane straining the membranes using MEMS, the tensile energy is increased, thereby diluting intrinsic losses. This approach increased the Q-factor of 2D material resonators by 91% and allowed measuring forces down to sub-piconewtons, outperforming commercially available silicon-based force sensors.","Dissipation dilution; Quality factor; Tunable resonators; 2D materials; MEMS; NEMS; force sensors","en","master thesis","","","","","","","","2025-01-31","","","","Mechanical Engineering","",""
"uuid:6258968b-3acb-4061-8e75-f1389e5292fd","http://resolver.tudelft.nl/uuid:6258968b-3acb-4061-8e75-f1389e5292fd","Crossing Borders Sustainably: Using Metagovernance to Activate Stakeholders to Facilitate Sustainable Mobility Transitions in a Cross-Border Context","van Daalhuizen, Thomas (TU Delft Architecture and the Built Environment; TU Delft Management in the Built Environment)","Chan, P.W.C. (mentor); Van den Berghe, K.B.J. (mentor); Delft University of Technology (degree granting institution)","2024","There is a need to broaden discussions on sustainable mobility beyond the prevalent focus on electric cars, particularly considering the challenges faced by border regions and marginalized groups that rely on public and soft transport. This study aims to fill this gap by examining the intricate dynamics of cross-border mobility transitions in Belgium and the Netherlands, with a specific focus on activating stakeholders and facilitating sustainable mobility transitions through the application of meta-governance.
Utilising a multifaceted research methodology, including an extensive literature review, in-depth case studies of HSL-Zuid and IJzeren Rijn, stakeholder interviews, this research navigates the complex landscape of meta-governance in cross-border regions.
The study reveals three pivotal tensions that disrupt current decision-making processes for cross-border connections: (1) National and Regional Imbalance in Decision-Making, (2) Formal and Informal Routes to Decision-Making and Flexibility, (3) Conflicting Interests. These tensions intricately impact governance styles, creating challenges and inefficiencies.
To address the identified issues, the research proposes actionable recommendations. Emphasising the need to harmonise national-regional governance frameworks, work on nuanced approaches to formal and informal routes, considerate divergent national interests, and heightened awareness of governance style interplay. Moreover, the research also highlights that metagovernance is already ingrained in current practices. The key lies in raising awareness of its presence among stakeholders, enabling a more informed and seamless navigation of the cross-border governance landscape. Metagovernance’s true value lies in its ability to articulate and navigate through different governance styles, adapting to various challenges and opportunities. While it may not always represent a novel approach, it serves as a critical analytical tool for understanding the dynamics of governance in complex infrastructure projects.","Metagovernance; Governance; Stakeholders; Cross-Border Context; Sustainable mobility; Transitions","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences","","51.247275, 5.555281"
"uuid:2a7fbfe3-6cd7-4634-92e0-160ae3901a70","http://resolver.tudelft.nl/uuid:2a7fbfe3-6cd7-4634-92e0-160ae3901a70","Complete Monopile Removal: FEM study of a monopile clamping method","Timmer, Hidde (TU Delft Civil Engineering & Geosciences)","Sluys, Lambertus J. (mentor); Alkisaei, H. (graduation committee); Kavoura, Dr. Florentia (graduation committee); Cristutiu, Teodora (mentor); Delft University of Technology (degree granting institution)","2024","A large number of offshore wind turbines have been installed in recent years, and even
more are being erected in current and future projects. The majority of these turbines
have been or are being built of monopile foundations. Eventually, both the turbine and
the foundation have to be decommissioned. However, decommissioning options for
monopile foundations are limited, especially for complete removal of the foundation.
This thesis aims to study a new removal method patented by the company Iv-Consult,
which could potentially make entire monopile removal possible. The method uses
deformation of the monopile wall by a clamping tool to generate a vertical force. Since
the thesis served as a preliminary study into the removal method, it was chosen to limit
the scope of this study to the monopiles that are expected to be decommissioned in the
near future. With this information, a single case of monopile with dimensions that are
representative for these monopiles was presented. To analyse the removal method on the
case monopile the finite element method was used. In order to ensure results obtained
using the finite element method are accurate and representative, a convergence study was
carried out. To determine the element type and the mesh size that was the most suitable,
two different models were used: a ring model and a small cylinder model. Each was
studied using different combinations of inputs. After the results from the convergence
were obtained, these results were used on the models with which the removal method
was studied. Different configurations of the removal method were analysed with the
aim of maximizing the force that can be generated by the method to overcome resistance
forces. As a final step, the resistance forces that need to be overcome were calculated
for different soil types and compared to the results obtained from the removal method
models to verify the feasibility of the method.
From the results of the convergence study, it was shown that it is possible to model
the removal method using the finite element method and obtain representative results.
The final results of this thesis showed that clamping the monopile multiple times
does not have a positive influence on the vertical force that can be generated. This is
because clamping the monopile only once caused the highest vertical force. However, the
forces generated using the different setups of the clamping method were not sufficient
to overcome the resistance forces. This shows that the removal method in the current
configurations is not feasible, without applying any soil resistance reducing methods.
In this retrospective study, Random Forest Regression was used to predict cross-sectional and longitudinal Functional Ambulation Category (FAC) and Six-item Cognitive Impairment Test (6CIT) after hip fracture using ambulatory accelerometry data. Accelerometry data and BPS functional assessments were available of 49 participants of the HIPCARE study, assessing prognostic determinants of outcome after hip fracture in the elderly.
Overall, cross-sectional FAC scores three months after hip fracture could be predicted with moderately low error, and categorized regression predictions showed high precision and recall. Cross-sectional 6CIT and both longitudinal regression models underperformed, but categorized regression predictions revealed mixed but more promising precision and recall.
It is expected that the predictive performance of models can be improved by increasing participant sample size with balanced samples over population-specific, prevalent ranges of BPS outcome scales and exploring additional machine learning models. In the future, accurate accelerometry-based predictions for individual patients needing rehabilitation could support personalized treatment and improve long-term biopsychosocial functioning.","","en","master thesis","","","","","","","","","","","","Technical Medicine","TM30004; 35 ECTS",""
"uuid:da110b6b-b9e3-4b0b-8252-7856893a1cff","http://resolver.tudelft.nl/uuid:da110b6b-b9e3-4b0b-8252-7856893a1cff","Instrument for remote sensing of methane based on photonic crystals","Algera, Johannes (TU Delft Aerospace Engineering; NWO-I/SRON Netherlands Institute for Space Research)","Loicq, J.J.D. (mentor); Siemons, Marijn (graduation committee); Delft University of Technology (degree granting institution)","2024","The miniaturization of space systems push for cheaper and more compact instruments. The use of photonic crystals as optical filters are a promising option for the miniaturization of spectrometers. This thesis is part of a project in SRON where a novel concept using photonic crystals is being investigated for Earth observation. Ways of using the transmission of photonic crystals for remote sensing of methane were explored. Later, the effects of the concentrations of other gases and the reflectance of the surface in the performance of the instrument were investigated. A method of selecting which photonic crystals to use in the instrument was developed and used to improve its performance. Finally, an optical design was made to estimate the volume of such an instrument.","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","CompressSpec",""
"uuid:6100375d-e4f4-4746-9b3f-a3641b27d976","http://resolver.tudelft.nl/uuid:6100375d-e4f4-4746-9b3f-a3641b27d976","Designing, manufacturing and testing bimorph piezoelectric twisting actuators","Baaij, Thomas (TU Delft Mechanical, Maritime and Materials Engineering)","Hunt, A. (graduation committee); Noel, L.F.P. (mentor); Delft University of Technology (degree granting institution)","2024","This thesis report contains two papers. The first paper is a literature study on mechanisms, smart actuated materials and controllable joints. In this paper, several smart materials are identified and it is discussed how they can be embedded in different mechanisms. From this paper, it is concluded that fast-response smart material twisting actuators do currently not exist. The second paper studies the design and development of such an actuator. The study presents a design and manufacturing methodology of a planer actuator that generates out-of-plane rotation. It first investigates different out-of-plane deformation modes and how they can be used to achieve the desired motion. Based on an analytical model on the shape morphing of piezoelectric macro fibre composites, a methodology is developed to generate out-of-plane twisting deformation. This concept is used to design a carbon black electrode pattern, which can be spray-deposited on a kapton substrate. This electrode is subsequently used to selectively actuate parts of a P(VDF-TrFE- CTFE) polymer layer. The selective stimulation of the layer results in the desired twisting deformation. This study demonstrates how flat designs can be laminated in a planar additive manufacturing process to induce complex 3D motion. The spray-deposition process was capable of manufacturing bimorph actuators with a 1.6mm resolution. The resulting actuators have a length of 41mm and a width of 10 to 20mm and a thickness of 120 to 139micron. The experiments are used to characterize the effect of the design parameters such as actuator width and thickness on the magnitude of the deformation. As theorized in the analytical model, the thinner more slender samples show the largest rotation which is measured to rotate up to 3.38 degrees. From the experiments it is also found that thinner samples show dielectric breakdown at much lower voltages, around 100V, compared to thicker samples from the same design that performed up to 480V. The study also investigates the quality of the deformation of the actuators, i.e. pure twisting or a combination of twisting and bending deformation. It is verified that uneven layers or asymmetric actuators show significant unimorph bending behaviour, with displacements up to 1.5mm while rotating 3.38 degrees. To the author's best knowledge, this study presents the first working prototypes of fast-response smart material twisting actuators.","Piezoelectric; Bimorph; P(VDF- TrFE- CTFE); Spray-deposition; Additive Manufacturing; twisting actuator; Rotation actuator","en","master thesis","","","","","","","","2026-01-10","","","","Mechanical Engineering | Mechatronic System Design (MSD)","",""
"uuid:f720ab40-0a1c-4c3b-b689-4491ef35a1b7","http://resolver.tudelft.nl/uuid:f720ab40-0a1c-4c3b-b689-4491ef35a1b7","Preference-Based Reinforcement Learninig in Demand Response Programs","Piccini, Pietro (TU Delft Electrical Engineering, Mathematics and Computer Science)","Cavalcante Siebert, L. (mentor); Delft University of Technology (degree granting institution)","2024","ncentive-based demand response (iDR) programs serve as important tools for distributed system operators (DSOs) to achieve a reduction in electricity demand during periods of grid overload. During these programs, participants can decide to curtail their consumption in exchange for financial incentives. Deciding the amount of curtailment for a participant is often the result of individual preferences. Reinforcement Learning (RL) methods have been employed to automate participants’ decision-making in these programs, often relying on predefined reward designs based on observed behavioral patterns. This thesis introduced PbRL-iDR: a reinforcement learning approach that can learn a reward function unique to individual participants by querying them for preference labels on a set of trajectories. PbRL-iDR trains the reward model and the policy on an alternating cycle. First, queries are sent to the simulated participant to update the current reward model. Later, the updated reward model is used to improve the policy. Variations of the PbRL-iDR algorithm are proposed to optimize query efficiency: active query selection (AQS) and parameter transfer from model ensemble (PTME). Through experimentation, PbRL-iDR demonstrated comparable performance to a DQN-based method, albeit with a slower convergence. An ablation study was performed to test the efficacy of AQS and PTME in reducing the number of queries necessary to learn a reward function. Results suggest that AQS can help the policy converge sooner and after fewer queries when compared to PbRL-iDR without AQS. The same experiment showed that using PTME failed to yield similar improvements.","preference-based reinforcement learning; learninig from human preferences; demand response; incentive-based demand response","en","master thesis","","","","","","","","","","","","Computer Science","","51.9988273,4.3739604"
"uuid:0901d86d-f1f4-45dd-b74e-7fc7a04625d5","http://resolver.tudelft.nl/uuid:0901d86d-f1f4-45dd-b74e-7fc7a04625d5","Realisation of green freight: a comparative analysis of alternative fuels in road freight transport: Evaluating Electric Battery Trucks, Hydrogen, and Bio-LNG trucks","Hamming, Paula (TU Delft Technology, Policy and Management)","Heijnen, P.W. (mentor); Annema, J.A. (graduation committee); Delft University of Technology (degree granting institution)","2024","Freight transport is a crucial component of our society and economy. However, achieving sustainability in this sector is complex, due to a lack of incentives among stakeholders. The heavy-duty road transport sector is struggling to meet European emission standards. To address this issue, a research study examined the impact of combining Battery Electric Trucks (BETs), Hydrogen trucks, and Bio-Liquefied Natural Gas (LNG) trucks on a network level. The study used freight simulation and refuelling location optimization through K-means to determine the cost and emissions of the system under different conditions. The results showed that Bio-LNG trucks and BETs are viable fuel options for sustainable freight transport, with Bio-LNG being immediately usable and BETs showing promise for future technological development. The study further revealed that BETs are a cost-effective and low-emission choice for short- and long-haul freight trips, particularly when using Mega Watt chargers and larger battery capacities. The research contributes to understanding the complexities of transitioning to greener freight transport and provides insights into policy implications. Future research could explore the broader social and environmental impacts of these alternative fuel options.","Sustainable road freight transport; Battery Electric Truck; Bio-LNG Truck; Hydrogen Truck; K-means","en","master thesis","","","","","","","","","","","","Systems Engineering, Policy Analysis and Management (SEPAM)","",""
"uuid:d4c7dc15-dfda-4790-a627-5a701ff0b5f1","http://resolver.tudelft.nl/uuid:d4c7dc15-dfda-4790-a627-5a701ff0b5f1","Develop an interface for model-informed prototyping of HAI interactions","Zhou, Jiayi (TU Delft Industrial Design Engineering)","Murray-Rust, D.S. (mentor); Mehrvarz, M.M. (mentor); Tsiakas, K. (graduation committee); Delft University of Technology (degree granting institution)","2024","As AI technology continues to advance, there's a growing need to integrate it into UX design. However, AI's unique characteristics do not seamlessly align with current design tools and mastering the technical aspects for designers is a significant challenge. The project goal is to develop a tool based on a developed semi-formal representation for Human-AI (HAI) interactions, which uses a set of communicative acts1 to specify the communicated information between users and AI models as exchanges of messages.
The project followed an iterative prototyping method across 4 phases. The Pre-Phase aimed at testing communicative acts with design students using a use case (""CV-Screening"") and paper materials. At the same time, it also expected to get insights on the data structure and develop the specific design considerations based on those for the Model-Informed Prototyping (MIP),
Phase 1 explored effective workflows of the digital prototype to present communicative acts by following the design considerations from the Pre-Phase and using the low-fidelity digital prototype in Figma. The use case in this phase was the same as that in the Pre-Phase.
In Phase 2, based on insights from the last two phases, there was a high-fidelity prototype in Figma which was inspired by the user journey map. It was used to assess if the design output achieved the design goals and considerations, and it helped the final test materials work better.
The Final Phase utilizes the refined digital prototype for the final test which had the same goals as that in Phase 2, providing important insights for future development.
The final output of the project is a partial prototype of a digital tool designed to facilitate the early stages of human-AI interaction design. Grounded in the principles of communicative acts and human-centered design, this tool assists designers during the Ideation stage of Design process. It achieves this by visualizing the roles, data, and information involved in the process of information exchange during Human-AI Interactions. The goal is to enhance efficiency and ease in designing these interactions.","Human-AI interaction Design; Model-Informed Prototyping; Iterative prototyping method; Communicative acts; UX Design Tool","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:0a34b7ef-d18b-4f86-be16-62128a52dd7c","http://resolver.tudelft.nl/uuid:0a34b7ef-d18b-4f86-be16-62128a52dd7c","Design of a High Voltage Arbitrary Wave Shape Generator for Dielectric Testing","Ganeshpure, D.A. (TU Delft High Voltage Technology Group)","Vaessen, P.T.M. (promotor); Bauer, P. (promotor); Ghaffarian Niasar, M. (copromotor); Delft University of Technology (degree granting institution)","2024","The integration of wind and solar energy through power electronic converters has introduced new challenges to High Voltage (HV) equipment in the electrical power system. Switchgear, cables, and transformers are now subject to higher dV/dt stress and complex wave shapes due to solid-state switching. This poses a threat to the reliability of the grid by weakening the dielectric material of these assets. Existing HV test sources face limitations in generating complex wave shapes and have restricted current capabilities. Building a customized test setup is time-consuming when combining multiple HV test sources for complex waveforms.
To overcome these challenges, an Arbitrary Wave shape Generator (AWG) for dielectric testing of HV grid assets is proposed. The Modular Multilevel Converter (MMC) topology is chosen for its modular structure, low harmonic content, and scalability to higher voltage levels. The initial focus is on dielectric testing of Medium Voltage (MV) class equipment, with the ultimate goal being the development of a modular prototype as part of a PhD project.
HV test requirements and procedures for conventional tests of MV class equipment are compiled, along with specifications for non-standard wave shapes in consideration of the hybrid grid. Two main HV test requirements are addressed in the PhD thesis: the output voltage range of 10 kV to 100 kV with a load capacitance range of 50 pF to 10 nF and a large-signal bandwidth up to 2.5 kHz. The second requirement involves generating steep pulses with a rise time of a few microseconds for a voltage magnitude of 250 kV across a capacitive load of 10 nF.
Despite the maturity of MMC technology for HVDC transmission, adapting it for HV AWG applications presents unique challenges. The thesis explores design trade-offs related to MMC parameters such as the number of Submodules (SMs) per arm, arm inductance, arm resistance, modulation technique, SM capacitance, and control system. Design criteria are developed and demonstrated through simulation models and a scaled-down prototype.
The control hardware of the HV AWG is addressed using a commercially available Real Time Simulator (RTS) named Typhoon-HIL. This choice is based on its flexibility to program arbitrary waveforms in the FPGA without coding in any special hardware description language. The performance is demonstrated in the scaled-down prototype, achieving sinusoidal waveforms up to 5 kHz reference frequency with THD less than 5%.
The second HV test requirement, steep pulse generation, is investigated with the MMC topology. It is found that the series-connected SMs of MMC make it challenging to obtain a short rise time across a large capacitive load. To address this, an integrated hybrid circuit of MMC and Marx generator circuit is proposed for complex waveforms with a rise time faster than 100 μs. Proper guidelines for choosing circuit parameters are provided and experimentally validated with a scaled-down prototype.","Dielectric Testing of Grid Assets; Arbitrary Wave shape Generator; modular multi-level converter (MMC); Marx generator; PD measurement","en","doctoral thesis","","","","","","","","2024-12-31","","","High Voltage Technology Group","","",""
"uuid:5ba30cd3-6fe0-47c9-8776-3f2090d20d40","http://resolver.tudelft.nl/uuid:5ba30cd3-6fe0-47c9-8776-3f2090d20d40","Review of H∞ Static Output Feedback Controller Synthesis Methods: Application to Fighter Aircraft Control","Schoon, Daam (TU Delft Aerospace Engineering)","Theodoulis, S.T. (mentor); de Visser, C.C. (graduation committee); Delft University of Technology (degree granting institution)","2024","To gain more insight into the performance of state-of-the-art Static Output Feedback (SOF) controller synthesis methods for H∞-control, quantitative comparisons are made between Lyapunov methods and well-known established non-smooth optimization methods, i.e. Hinfstruct and HIFOO. Three methods were deemed to be the most promising to compete and were bundled into one toolbox named SOFHi. The algorithms were extended to incorporate structured SOF and a variant of SOFHi was proposed to significantly improve upon the computational efficiency of the original implementation. Extensive comparisons show that SOFHi was able to compete with the established non-smooth methods and even able to significantly outperform one of them. Lastly, an elaborate flight control benchmark example is given to showcase the effectiveness of the algorithms, which involves the design of a gain-scheduled normal acceleration Control Augmentation System (CAS) for a highly maneuverable fighter aircraft.","SOF; Static Output Feedback; Static; Output; Feedback; H∞; H-infinity; infinity; H-infinity control; H_infinity; Mixed sensitivity; sensitivity function","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:fc37f3d2-2cd6-4068-ad79-893ffd9cdc1d","http://resolver.tudelft.nl/uuid:fc37f3d2-2cd6-4068-ad79-893ffd9cdc1d","Using our tools backwards, AF detection by confusing time and frequency","Kraaijeveld, Michael (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Signal Processing Systems)","Hendriks, R.C. (mentor); Varon, Carolina (mentor); Martinez, Jorge (graduation committee); Delft University of Technology (degree granting institution)","2024","Atrial Fibrillation or AF is the most common heart rhythm anomaly affecting millions of people. This work explores the possibilities of reinterpreting speech processing techniques for use in atrial fibrillation detection. An existing method of modelling single heartbeat, single lead ECG signals by means of an ARMA model's amplitude response as a time domain signal is implemented. The parameters of the models are then used for AF detection by means of detecting P wave absence. For this detection, the distribution of the P wave associated parameters is compared to a GMM model of normal sinus rhythm beats obtained from a large number of recordings from different sources.","heart; Atrial Fibrillation; Electrocardiogram (ECG); Modelling; Detection; ARMA models; Gaussian Mixture Modeling (GMM)","en","master thesis","","","","","","","","","","","","Electrical Engineering | Signals and Systems","",""
"uuid:27b162ea-ca7a-4134-bdda-0f16857d45d2","http://resolver.tudelft.nl/uuid:27b162ea-ca7a-4134-bdda-0f16857d45d2","Fusing Bird’s Eye View Map Encoding With Simulated Sounds for Generalizable Non-Line-Of-Sight Vehicle Detection","Bērmans, Boriss (TU Delft Electrical Engineering, Mathematics and Computer Science)","Hung, H.S. (mentor); Kooij, J.F.P. (graduation committee); Wang, S. (graduation committee); Delft University of Technology (degree granting institution)","2024","Detecting nearby vehicles involves utilizing data from various sensors installed on a car as it moves. Common sensors for identifying nearby vehicles include LiDAR, cameras, and RADAR. However, all of these sensors suffer from the same issue -- they cannot detect an approaching vehicle that is not yet visible. Hence, this thesis explores the potential of using a microphone array -- an array of sensors capable of detecting vehicles that are out of sight. Exploring prior research on detecting obstructed vehicles using sound reveals an existing model capable of detecting nearby vehicles approaching from behind blind corners. However, as the local geometry around the ego vehicle affects the perceived sound patterns, this model was only designed to work within a specific set of T-junctions. Therefore, the thesis aims to take a step further and develop a detection model capable of detecting vehicles behind blind corners in environments not included in the training set of the deployed model. This is challenging for multiple reasons. First, literature review revealed a lack of suitable datasets comprising sounds from approaching vehicles behind blind corners within various road junctions. In addition, microphones, like other sensors, come with limitations. Sound inherently provides less spatial information compared to commonly used sensors in autonomous driving, such as LiDAR or cameras. Considering sound propagation variations in different road junction geometries, building a model adaptable across diverse junction types presents a challenge. To overcome the data scarcity and sound's inherent spatial limitations, the study investigates the potential of employing simulated acoustic responses within artificial road environments as training data for real-world vehicle detection. Simultaneously, to complement the sounds inherent advantage of detecting objects that are out of sight, the thesis proposes to use a Bird's Eye View (BEV) encoding of the top-down map from the driving vehicle's perspective. Having an encoding of the top-down map of the current driving environment would allow a detection model to expect sound signatures commonly observed within a given setting. Overall, the assessment of acoustic simulations could not outline a singular configuration of simulation properties allowing realistic sound propagation for any kind of considered junctions when hearing an approaching vehicle. However, it was observed that the utilization of specific simulation parameters can result in realistic sound propagation within the given junction. Subsequently, evaluating a novel BEV encoding within the newly proposed acoustic detection pipeline demonstrated either equivalent or superior performance compared to a model relying solely on sound. Overall, this research underscores the potential of incorporating BEV encoding in non-line-of-sight acoustic detection and suggests the promise of acoustic simulations within the field. This study contributes to advancing the integration of sound as an additional data modality in vehicle detection.","Signal Processing; Autonomous driving; Acoustic Localization; Non-Line-of-Sight; Microphone array; Simulations; Bird's Eye View","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:99ae7b9f-dbc6-49c9-85a7-070c4e1b6938","http://resolver.tudelft.nl/uuid:99ae7b9f-dbc6-49c9-85a7-070c4e1b6938","Non-linear wave loads on next-generation offshore wind turbines","Holsappel, Tim (TU Delft Mechanical, Maritime and Materials Engineering)","Lavidas, G. (mentor); Delft University of Technology (degree granting institution)","2024","br/>In response to the escalating demand for renewable energy, wind turbines and their support structures have witnessed exponential growth in size in recent decades. However, this expansion presents substantial challenges, particularly in the face of severe storms and large waves, raising concerns about resonance-related issues. Accurate modeling of asymmetrical, non-linear waves generated during storms becomes crucial for safe and cost-effective wind turbine design. The prevalent approach embeds higher-order non-linear waves into linear theory, but recent studies have unveiled uncertainties in this method, necessitating innovative techniques for simulating non-linear waves. Some studies propose numerical wave models (NWMs) like SWASH and OceanWave3D, treated as numerical wave tanks (NWTs), as alternatives for predicting wave loads on offshore wind turbines. A comparative analysis between SWASH and OW3D reveals significant discrepancies, particularly in OW3D results, prompting further investigation into potential setup issues. Both non-linear models consistently report higher loads than the stream function method due to increased local accelerations, and differences in wave spectra underscore their ability to account for non-linear wave interactions. The study underscores the stream function's underestimation of loads, emphasizing the necessity of accurate non-linear wave modeling for predicting extreme loads. Recommendations for future research include extended convergence studies, user experience considerations, and a closer examination of non-linear effects on fatigue load predictions.","","en","master thesis","","","","","","","","","","","","Offshore and Dredging Engineering","",""
"uuid:2c93f1af-bf49-4353-b9b9-c6ed8d62d3c9","http://resolver.tudelft.nl/uuid:2c93f1af-bf49-4353-b9b9-c6ed8d62d3c9","Epidemics on Static and Adaptive Networks","Achterberg, M.A. (TU Delft Network Architectures and Services)","Van Mieghem, P.F.A. (promotor); Kooij, Robert (promotor); Delft University of Technology (degree granting institution)","2024","The COVID-19 pandemic has had a disruptive impact on healthcare systems and everyday life of the majority of the people around the globe. Despite many years of research on network epidemiology, many key aspects of disease transmission and in particular the response of people to the spread of a disease, remain poorly understood. On the basis of epidemiological modelling lie the Susceptible-Infected-Susceptible (SIS) and Susceptible-Infected-Recovered (SIR) models. In this dissertation, we aim to improve the understanding of the spread of contagious diseases, with an emphasis on the interplay between disease spread and personal behaviour, applied to the SIS and SIR models. The first part starts with the analysis of the eigenvalue spectrum of the infinitesimal generator of the Markovian SIS model with self-infections (Chapter 2). Based on the eigenvalue spectrum, which we believe encodes the majority of the dynamics, we derive an alternative definition of the epidemic threshold. We show that the epidemic threshold approximately coincides with the effective infection rate for which the third-largest eigenvalue is minimal. Contrary to the SIS process, where only an eigenvalue analysis is possible, the SIR process is completely solved on an arbitrary, heterogeneous network (Chapter 3). The benefit of the exact solution is demonstrated by analytically computing the time when the number of infections is maximal. The second part concerns the interplay between the spread of a disease and the response of people to the disease spread. We develop the Generalised Adaptive SIS (GASIS) model to describe how individuals break and create links in the contact graph. The decisions for breaking or creating links are based on the viral state of the nodes attached to that link. For all 36 instances in the G-ASIS model, we analyse the relation between the epidemic threshold and the effective link-breaking rate (Chapter 4). We derive the first-order and second-order mean-field approximation of the G-ASIS model (Chapter 5) and illustrate that the second-order approximation is able to qualitatively approximate the Markovian model more accurately than the first-order approximation. The G-ASIS mean-field model is extended to arbitrary link-breaking and link-creation responses, which are not only related to the number of susceptible and infectious neighbours of a node, but may also depend on the presence of the virus in the whole population (Chapter 6). For all possible link-breaking and link-creation responses, epidemic waves cannot occur in the mean-field adaptive SIS process. In the final part,we develop theNetwork-Inference-based Prediction Algorithm(NIPA) for forecasting the spread of contagious diseases on heterogeneous networks (Chapter 7). The contact graph is assumed to be unknown and is inferred by NIPA from the number of reported cases. NIPA is a hybrid method, combining epidemiological knowledge, machine-learning and networks. Network-based forecasting, and NIPA in particular, seems favourable for predicting epidemic outbreaks, which is demonstrated by showing that NIPA outperforms many other forecasting algorithms for estimating the spread of COVID-19.","Mathematical epidemiology; Adaptive networks; Markov processes","en","doctoral thesis","","978-94-6384-514-4","","","","","","","","","Network Architectures and Services","","",""
"uuid:4fa3a292-477c-4ff0-b01a-e7d90b66ec2a","http://resolver.tudelft.nl/uuid:4fa3a292-477c-4ff0-b01a-e7d90b66ec2a","Exploring Active Inference and Model Predictive Path Integral Control: A Journey from Low-Level Commands to Task and Motion Planning","Pezzato, C. (TU Delft Robot Dynamics)","Wisse, M. (promotor); Hernández, Carlos (copromotor); Delft University of Technology (degree granting institution)","2024","In an ever-evolving society, the demand for autonomous robots equipped with human-level capabilities is becoming increasingly imperative. Various factors, such as an aging population and a shortage of labor for repetitive and physically demanding tasks, have underscored the need for capable autonomous robots to assist us in our daily activities. However, despite the recent advancements in robotics, the field still faces significant challenges in delivering on its promises of developing general-purpose robots with human-level capabilities for everyday tasks. This thesis aims to develop control algorithms at different levels of abstraction to achieve more robust, adaptive, and reactive robot behavior for long-term tasks in dynamic environments.
Since our ultimate goal is to achieve human-level performance, a natural starting point is to investigate theories of human intelligence and how they can be applied to real robots, such as mobile manipulators. In this regard, one prominent theory is Active Inference, a popular and influential concept that can explain a wide range of cognitive functions, from motor control to high-level decision-making. Active Inference was developed based on the free-energy principle providing an explanation for embodied perception-action loops. While the free-energy principle and Active Inference have garnered significant attention among neuroscientists, their application to robotics remains largely unexplored, presenting an exciting avenue for research in this thesis. At the same time, it is also important to recognize that we should not confine ourselves solely to theories of human intelligence and their inherent limitations. Machines and humans are built upon fundamentally different structures, which opens up possibilities for alternative approaches. Consequently, this thesis also investigates the use of Model Predictive Path Integral Control (MPPI), which stems from a different formulation of free-energy that is not bound to biological assumptions. By exploring the application of Active Inference to low-level robot control and task planning, as well as the utilization of MPPI for motion planning, this thesis provides advancements in robot control at different levels of abstraction. More concretely, this thesis contributes to the following four areas: 1) Lowlevel adaptive and fault-tolerant control, 2) Reactive high-level decision making, 3) Contact-rich motion planning, and 4) Reactive task and motion planning (TAMP)…
This research investigates the distinct characteristics of blockchain technology to safeguard against the deterioration of handover information quality in the post-construction phase. The significance of effective management of handover information is highlighted by global building failures, such as the Grenfell Tower fire in London, UK. Despite existing technological interventions, there remains a paucity of understanding regarding the factors contributing to the decline in the quality of handover information during the post-construction phase.
Design/methodology/approach
This study employed a multi-case studies approach across five higher education institutions. It involved conducting semi-structured interviews with 52 asset management professionals, uncovering the underlying reasons for the decline in handover information quality. Building on these insights, the study performed a mapping exercise to align these identified factors with blockchain technology features and information quality dimensions, aiming to evaluate blockchain’s potential in managing quality handover information.
Findings
The study findings suggest that blockchain technology offers advantages but has limitations in addressing all the identified quality issues of managing handover information. Due to the lack of an automated process and file-based information exchange, updating handover information still requires an error-prone manual process, leading to potential information loss. Additionally, no solutions are available for encoding drawings for updates and validation.
Originality/value
This study proposes a framework integrating blockchain to enhance the information management process and improve handover information quality.","Handover information; Information quality; Asset information management; Blockchain technology; Higher education institutions","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-04","","","Integral Design & Management","","",""
"uuid:28204e37-7122-4d99-9c42-a4f143583c0d","http://resolver.tudelft.nl/uuid:28204e37-7122-4d99-9c42-a4f143583c0d","The Letter Rack","Corbo, S. (TU Delft Space & Type)","","2024","“The Letter Rack” is a speculative exercise in exploring the emergence of new spatial relationships when we stop thinking of future cities in terms of figure/ground duality and instead start looking at them as a continuous assemblage of forms and signs.
This form of digital divertissement in drawings originates from the reinterpretation of the so-called “trompe l’oeil,” a pictorial genre used for centuries to depict illusionistic scenes that give spectators the impression that they are facing real, three-dimensional objects. More specifically, the Letter Rack refers to the 1668 trompe l’oeil by Cornelis Norbertus Gijsbrechts, which represents a board partition populated by envelopes, objects, and a music book. The Letter Rack borrows the spatial organization of Gijsbrechts’ painting and, in general, some of the ingredients common to the tradition of trompe l’oeil, such as the use of metaphor, allegory, or symbolism, to reverse their meaning. It turns realistic representations into a hypothetical scenario in which building types and urban spaces meet, collide, and fuse in novel configurations. In other words, The Letter Rack is an inverted digital trompe l’oeil.","spatial relationships; digital divertissement; trompe l'oeil; urban assemblage; hypothetical scenario","en","journal article","","","","","","","","","","","Space & Type","","",""
"uuid:10311077-2304-46cd-b9e2-0eb920b2295f","http://resolver.tudelft.nl/uuid:10311077-2304-46cd-b9e2-0eb920b2295f","Deep Reinforcement Learning for Orchestrating Cost-Aware Reconfigurations of vRANs","Murti, Fahri Wisnu (University of Oulu); Ali, Samad (University of Oulu); Iosifidis, G. (TU Delft Networked Systems); Latva-aho, Matti (University of Oulu)","","2024","Virtualized Radio Access Networks (vRANs) are fully configurable and can be implemented at a low cost over commodity platforms to enable network management flexibility. In this paper, a novel vRAN reconfiguration problem is formulated to jointly reconfigure the functional splits of the base stations (BSs), locations of the virtualized central units (vCUs) and distributed units (vDUs), their resources, and the routing for each BS data flow. The objective is to minimize the long-term total network operation cost while adapting to the varying traffic demands and resource availability. In the first step, testbed measurements are performed to study the relationship between the traffic demands and computing resources, which reveals high variance and depends on the platform and its load. Consequently, finding the perfect model of the underlying system is non-trivial. Therefore, to solve the proposed problem, a deep reinforcement learning (RL)-based framework is proposed and developed using model-free RL approaches. Moreover, the problem consists of multiple BSs sharing the same resources, which results in a multi-dimensional discrete action space and leads to a combinatorial number of possible actions. To overcome this curse of dimensionality, action branching architecture, which is an action decomposition method with a shared decision module followed by neural network is combined with Dueling Double Deep Q-network (D3QN) algorithm. Simulations are carried out using an O-RAN compliant model and real traces of the testbed. Our numerical results show that the proposed framework successfully learns the optimal policy that adaptively selects the vRAN configurations, where its learning convergence can be further expedited through transfer learning even in different vRAN systems. It also offers significant cost savings by up to 59% of a static benchmark, 35% of Deep Deterministic Policy Gradient with discretization, and 76% of non-branching D3QN.","action branching; Computational modeling; Computer architecture; Costs; D3QN; Data models; deep reinforcement learning; Load modeling; network virtualization; Neural networks; O-RAN; orchestration; Radio access networks (RANs); Routing","en","journal article","","","","","","","","","","","Networked Systems","","",""
"uuid:756aa692-d9be-4634-b9b0-3710442dd770","http://resolver.tudelft.nl/uuid:756aa692-d9be-4634-b9b0-3710442dd770","A Review of Automatic Classification of Drones Using Radar: Key Considerations, Performance Evaluation and Prospects","Ahmad, Bashar I. (University of Cambridge; Thales Land and Air Systems); Rogers, Colin (Thales Land and Air Systems); Harman, Stephen (Thales UK); Dale, Holly (University of Birmingham); Jahangir, Mohammed (University of Birmingham); Antoniou, Michael (University of Birmingham); Baker, Chris (University of Birmingham); Newman, Mike (Thales UK); Fioranelli, F. (TU Delft Microwave Sensing, Signals & Systems)","","2024","Automatic target classification or recognition is a critical capability in noncooperative surveillance with radar in several defence and civilian applications. It is a well-established research field and numerous techniques exist for recognizing targets, including miniature unmanned air systems or drones (i.e., small, mini, micro, and nano platforms), from their radar signatures. These algorithms have notably benefited from advances in machine learning (e.g., deep neural networks) and are increasingly able to achieve remarkably high accuracies. Such classification results are often captured by standard, generic, object recognition metrics, and originate from testing on simulated or real radar measurements of drones under high signal to noise ratios. Hence, it is difficult to assess and benchmark the performance of different classifiers under realistic operational conditions. In this article, we first review the key challenges and considerations associated with the automatic classification of miniature drones from radar data. We then present a set of important performance measures, from an end-user perspective. These are relevant to typical drone surveillance system requirements and constraints. Selected examples from real radar observations are shown for illustration. We also outline here various emerging approaches and future directions that can produce more robust drone classifiers for radar.","Airborne radar; classification; deep learning; Drones; non-cooperative surveillance; radar; Radar; Radar cross-sections; Radar tracking; Surveillance; Target tracking; unmanned air traffic management","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-27","","","Microwave Sensing, Signals & Systems","","",""
"uuid:e99316a3-1ec6-46f3-9394-6806b2116903","http://resolver.tudelft.nl/uuid:e99316a3-1ec6-46f3-9394-6806b2116903","Joint Ranging and Phase Offset Estimation for Multiple Drones using ADS-B Signatures","Mohammadkarimi, M. (TU Delft Signal Processing Systems); Leus, G.J.T. (TU Delft Signal Processing Systems); Rajan, R.T. (TU Delft Signal Processing Systems)","","2024","A new method for joint ranging and Phase Offset (PO) estimation of multiple drones/aircrafts is proposed in this paper. The proposed method employs the superimposed uncoordinated Automatic Dependent Surveillance-Broadcast (ADS-B) packets broadcasted by drones/aircrafts for joint range and PO estimation. It jointly estimates range and PO prior to ADS-B packet decoding; thus, it can improve air safety when packet decoding is infeasible due to packet collision. Moreover, it enables coherent detection of ADS-B packets, which can result in more reliable multiple target tracking in aviation systems using cooperative sensors for detect and avoid (DAA). By minimizing the Kullback-Leibler Divergence (KLD) statistical distance measure, we show that the received complex baseband signal coming from K uncoordinated drones/aircrafts corrupted by Additive White Gaussian Noise (AWGN) at a single antenna receiver can be approximated by an independent and identically distributed (i.i.d.) Gaussian Mixture (GM) with 2^{K} mixture components in the two-dimensional (2D) plane. While direct joint Maximum Likelihood Estimation (MLE) of range and PO from the derived GM Probability Density Function (PDF) leads to an intractable maximization, our proposed method employs the Expectation-Maximization (EM) algorithm to estimate the modes of the 2D Gaussian mixture followed by a reordering estimation technique through combinatorial optimization to estimate range and PO. An extension to a multiple antenna receiver is also investigated in this article. While the proposed estimator can estimate the range of multiple drones/aircrafts with a single receive antenna, a larger number of drones/aircrafts can be supported with higher accuracy by the use of multiple antennas at the receiver. The effectiveness of the proposed estimator is supported by simulation results. We show that the proposed estimator can jointly estimate the range of multiple drones/aircrafts accurately.","Range estimation; phase offset; cooperative navigation; expectation-maximization (EM); Gaussian mixture (GM); ADS-B; multiple receive antennas; detect and avoid (DAA)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-26","","","Signal Processing Systems","","",""
"uuid:c2b4bb5a-d23b-4f2c-8b4c-057d7ff7f6ea","http://resolver.tudelft.nl/uuid:c2b4bb5a-d23b-4f2c-8b4c-057d7ff7f6ea","Connected Slot Array with Interchangeable ADL Radome for sub-8 GHz 5G Applications","Ozzola, R. (TU Delft Tera-Hertz Sensing); Neto, A. (TU Delft Tera-Hertz Sensing); Imberg, Ulrik (Huawei Technologies Sweden AB); Cavallo, D. (TU Delft Tera-Hertz Sensing)","","2024","We present a dual-polarized connected array of slots with an artificial dielectric layer (ADL) radome for mobile communication applications operating in the sub-6 GHz and the upper 6 GHz bands of 5G. The radiating slots are combined with two interchangeable ADL radomes with different thicknesses, targeting the bands 6-8 and 2-8 GHz, respectively. This highlights the main property of the ADL radome, which realizes an impedance transformer whose bandwidth is proportional to the height of the structure. Moreover, the ADL anisotropy allows for wide scanning, up to 60° in the main planes for both radomes, without scan blindness. An $8\,\, \times \,\, 8$ prototype array has been manufactured and tested with the two ADL radomes. The measured results of the active voltage standing wave ratio (VSWR) and the radiation patterns are reported to validate the design.","5G antenna arrays; artificial dielectrics; connected arrays; mobile communications; phased arrays; wideband arrays","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-09","","","Tera-Hertz Sensing","","",""
"uuid:588a73ad-98f3-48c8-b238-68e7702f5518","http://resolver.tudelft.nl/uuid:588a73ad-98f3-48c8-b238-68e7702f5518","Who are the value transformers, value co-operators and value gatekeepers? New routes to value preservation in a sufficiency-based circular economy","Haase, Louise Møller (Aalborg University); Mugge, R. (TU Delft Responsible Marketing and Consumer Behavior); Mosgaard, Mette Alberg (Aalborg University); Bocken, Nancy (Universiteit Maastricht); Jaeger-Erben, Melanie (Brandenburg University of Technology); Pizzol, Massimo (Aalborg University); Jørgensen, Michael Søgaard (Aalborg University)","","2024","Value preservation is key for the transition from a linear economy to a sufficiency-based circular economy. However, to keep the value of products and materials at the highest level possible over time, different actors such as businesses, designers, consumers, and policymakers must know when value is reduced during a product's lifetime, and how to capture and preserve this value. This study results in a comprehensive mapping of factors with a negative impact on the perceived value of products from a consumer's perspective and suggests new routes to value preservation, as a way of turning the negative factors into positive changes. Next, the paper presents a conceptual model for value preservation. The model identifies new key actors: value transformers (product developers), value co-operators (consumers), value gatekeepers (businesses), and value accountants (policymakers) and suggests important changes to their linear practices, which are needed for the sufficiency-based circular economy paradigm to flourish.","Value preservation; Circular economy; Inner loops; Actor roles; Circular behaviour; Value chain dynamics; Lifecycle","en","journal article","","","","","","","","","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:a16f8f3f-6dd2-4700-89d1-93c89a65aee8","http://resolver.tudelft.nl/uuid:a16f8f3f-6dd2-4700-89d1-93c89a65aee8","Developing a Model to Study the Climate Change Impact on River Bifurcations in Engineered Rivers","Chowdhury, M. Kifayath (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Blom, A. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Ylla Arbos, C. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Schielen, R.M.J. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Rijkswaterstaat)","","2024","Climate change is responsible for global shifts in precipitation patterns and an overall in-crease in global temperatures. The transi-tions are anticipated to modify the river hydro-graph and sea level. The changes to the hy-drograph are also likely to influence sediment flux. These alterations imply shifts in both up-stream and downstream boundaries for river bifurcations. However, the resulting bifurca-tion response remains uncertain and warrants further investigation. Our objective is to un-derstand the extent of large-scale and long-term response of river bifurcations to climate change. We take the Upper Dutch Rhine bifur-cation region as our case study and develop a 1D hydro-morphodynamic model representing the system to achieve this goal.","river bifurcation; Rhine River; climate change; long term morphological change; Pannerdense Kop","en","abstract","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:4e37e532-a378-4b02-935a-af24b45d6088","http://resolver.tudelft.nl/uuid:4e37e532-a378-4b02-935a-af24b45d6088","A Field Study on Groyne Field Nourishments","Liptiay, E.J.A. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Blom, A. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Sloff, C.J. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Deltares)","","2024","Over the past century, the main channel of the Waal has experienced erosion of approx-imately 1-2 metres (Ylla Arb´os et al., 2021; Chowdhury et al., 2023). This erosion leads to various problems such as instability of struc-tures or disruption to shipping. To address this ongoing degradation, a potential solution is the implementation of sediment nourishments.
Recent pilot studies have been conducted in 2016 and 2019 to investigate the feasibility of using sediment nourishments in the main channel of the Dutch Rhine (Becker, 2023). Another possibility of nourishing is to add sed-iment to the groyne fields. Under the influence of currents and ship waves, sediment is ex-pected to be transported to the main channel, causing a groyne field to act as a sand mo-tor. To explore this concept, Rijkswaterstaat initiated a pilot project with sediment nourish-ments in three groyne field clusters along the Waal during the fall of 2023. The pilot includes an extensive measurement campaign.","groyne fields; sediment nourishments; river morphology","en","abstract","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:bb531b96-76c8-499c-bc76-e49002f01190","http://resolver.tudelft.nl/uuid:bb531b96-76c8-499c-bc76-e49002f01190","Accuracy of Numerical Morphological Models based on Simplified Hydrodynamics","Barneveld, H.J. (Wageningen University & Research; HKV Lijn in Water); Mosselman, E. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Deltares); Chavarrías, V. (Deltares); Hoitink, A.J.F. (Wageningen University & Research)","","2024","Sustainable river management often requires long-term morphological simulations. As the future is unknown, uncertainty needs to be accounted for, which may require probabilistic simulations covering a large parameter domain. Even for one-dimensional models, simulation times can be long. One of the acceleration strategies is simplification of models by neglecting terms in the governing hydrodynamic equations. Examples are the quasi-steady model and the diffusive wave model, both widely used by scientists and practitioners. We established under which conditions these simplified and often more efficient models are accurate.","Numerical modelling; Morphology; Stability Analysis","en","abstract","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:546563b7-d111-4079-a57e-e44ac42d07b9","http://resolver.tudelft.nl/uuid:546563b7-d111-4079-a57e-e44ac42d07b9","Exergy-Based Improvements of Sustainable Aviation Fuels: Comparing Biorefinery Pathways","Silva Ortiz, P. (Technische Universität München); de Oliveira Junior, Silvio (Universidade de São Paulo); Mariano, Adriano Pinto (University of Campinas); Jocher, Agnes (Technische Universität München); Posada Duque, J.A. (TU Delft BT/Biotechnology and Society)","","2024","The aeronautical sector faces challenges in meeting its net-zero ambition by 2050. To achieve this target, much effort has been devoted to exploring sustainable aviation fuels (SAF). Accordingly, we evaluated the technical performance of potential SAF production in an integrated first- and second-generation sugarcane biorefinery focusing on Brazil. The CO2 equivalent and the renewability exergy indexes were used to assess environmental performance and impact throughout the supply chain. In addition, exergy efficiency (ηB) and average unitary exergy costs (AUEC) were used as complementary metrics to carry out a multi-criteria approach to determine the overall performance of the biorefinery pathways. The production capacity assumed for this analysis covers 10% of the fuel demand in 2020 at the international Brazilian airports of São Paulo and Rio de Janeiro, leading to a base capacity of 210 kt jet fuel/y. The process design includes sugarcane bagasse and straw as the feedstock of the biochemical processes, including diverse pre-treatment methods to convert lignocellulosic resources to biojet fuel, and lignin upgrade alternatives (cogeneration, fast pyrolysis, and gasification Fischer-Tropsch). The environmental analysis for all scenarios shows a GHG reduction potential due to a decrease of up to 30% in the CO2 equivalent exergy base emissions compared to fossil-based jet fuel.","exergy and environmental assessment; biojet fuel production; biorefinery performance measurement","en","journal article","","","","","","","","","","","BT/Biotechnology and Society","","",""
"uuid:99debde4-f429-47a1-9858-ada00c3e94f8","http://resolver.tudelft.nl/uuid:99debde4-f429-47a1-9858-ada00c3e94f8","Flow partitioning between branches of the Karnali river in Nepal","Gautam, K. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Wolf, M.E. (TU Delft Civil Engineering & Geosciences); Bogaard, T.A. (TU Delft Water Resources); Blom, A. (TU Delft Rivers, Ports, Waterways and Dredging Engineering)","","2024","The dynamics of the bifurcating Karnali river in the western plains of Nepal and India is governed by the geomorphological processes in an alluvial fan. The dynamic branches showcase a notable degree of braiding, dominant channel switching and unequal discharge partitioning. Since recent switching of the dominant channel of Karnali system occurred after an intense monsoon in 2009, the eastern Geruwa branch of the system, which used to be dominant channel passing through the Bardiya National Park, is now receiving a lower share of discharge. This situation exacerbates in the low flow periods when there is very small flow in the Geruwa branch. This decreasing discharge has been associated with depleting diversity of wildlife habitat in Bardiya National Park (Bijlmakers et al., 2023). For sustainable habitat management in the Bardiya National Park, there is a necessity to study the dynamic Karnali river and its two branches, the eastern Geruwa branch and the western Kauriala branch. Activities such as sediment mining, construction of irrigation and hydropower and inter-basin water transfer projects will potentially influence the system dynamics. Our objective is to understand the switching behaviour of the Karnali system to the natural dynamics such as bend sorting (Baar et al., 2020; Parker & Andrews, 1985) of sediments at the location where water from the main Karnali enters the Geruwa branch, and offer understanding of system response to human interventions especially with regards to the distribution of discharge between the Geruwa and Kauriala branches. We combine the technique of field observations and numerical modelling to study the system.","river bifurcation; field observation","en","abstract","","","","","","","","","Civil Engineering & Geosciences","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:629471af-0673-44b0-95ac-10c269f46c67","http://resolver.tudelft.nl/uuid:629471af-0673-44b0-95ac-10c269f46c67","Using an idealized network model as the physical module for a salt intrusion serious game","den Haan, Robert-Jan (University of Twente); Biemond, Bouke (Universiteit Utrecht); Baart, F. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Deltares)","","2024","Salt intrusion is a growing problem in many deltas around the world. During periods with low river discharges, salinity upstream in a delta increases and affects freshwater availability, ecology, and other delta functions. For example, in the Rhine-Meuse estuary (the Netherlands), brackish water can reach drinking water intakes about 40 km from the estuary mouth during droughts. Salt intrusion is likely to become more severe in the context of climate change, as a result of sea level rise and a lower river discharge during droughts.
The challenges with salt intrusion for the Netherlands are addressed in the Salti Solutions research program. Within this program the Delta Management Game offers an interactive environment where policy-making stakeholders can experience salt intrusion management and experiment with adaptation and mitigation strategies in the Rhine-Meuse estuary. As a serious game, the goal is for players to “learn by taking actions and by experiencing their effects through feedback mechanisms that are deliberately built into and around the game” (Mayer, 2009, p. 825).
A particular design challenge for serious games is simplifying the environmental system and sufficiently representing the relevant physics, while offering exploratory and experimentation through (near-)instant, interactive feedback. The physical module for salt intrusion in the Delta Management Game should be able to deal with, among others, changes in bathymetry (e.g. depth or width of waterways, adding a sill) of the estuary in the game, while offering relatively quick feedback.","Idealized modelling; Serious game; Salt intrusion; Climate change","en","abstract","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:7721b745-fcd1-46d0-a90c-026364ddb557","http://resolver.tudelft.nl/uuid:7721b745-fcd1-46d0-a90c-026364ddb557","Flow-induced fragmentation and mixing of eDNA for river biodiversity assessment","Dercksen, J.A. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Stancanelli, L.M. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Trimbos, Krijn B. (Universiteit Leiden); Blom, A. (TU Delft Rivers, Ports, Waterways and Dredging Engineering)","","2024","River restoration is an established method for the rehabilitation of river ecosystems in order to combat the current declines of freshwater biodiversity (Wohl et al., 2005; WWF, 2022). The urgency of restoration is recognized internationally, as the IUCN has proclaimed 2021-2030 to be the ‘Decade on Ecosystem Restoration’ (Cooke et al., 2022). So far only few restoration projects have been evaluated based on monitoring data (England et al., 2021), and there is a need for monitoring techniques to assess restoration practices.
The analysis of environmental DNA (eDNA) has gained popularity in the last decades, as it allows for rapid standardized biomonitoring across the tree of life, requires a reduced dependence on taxonomic expertise for species identification, and it is cheaper than traditional monitoring methods. Depending on the organism, eDNA is shed by its host in forms such as mucous, shed skin cells, and faeces. After release, eDNA is exposed to a wide spectrum of environmental variables that may impact its state, transport capacity, fate, and the subsequent inference made by the practitioner (Barnes and Turner, 2016). Our objective is to study how eDNA quantities are affected by flow and sediment transport in river ecosystems.","environmental DNA; biomonitoring; fragmentation","en","abstract","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:a6969f0a-c0b9-43f3-baec-4f40b4fa8a19","http://resolver.tudelft.nl/uuid:a6969f0a-c0b9-43f3-baec-4f40b4fa8a19","Mitigation of Channel Bed Erosion through Floodplain Lowering and Nourishments","Ylla Arbos, C. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Schielen, R.M.J. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Rijkswaterstaat); van Vuren, Saskia (Rijkswaterstaat); Snoek, Yvo (Rijkswaterstaat); Blom, A. (TU Delft Rivers, Ports, Waterways and Dredging Engineering)","","2024","Channel adjustment in engineered rivers is often associated with channel bed incision (e.g., Chowdhury et al., 2023, Czapiga et al., 2022a, 2022b, Ylla Arbós et al., 2021). Channel bed incision reduces the stability of in-river structures, exposes river-crossing cables and pipelines, and the spatial variability of channel bed incision due to less erodible reaches creates shipping bottlenecks.
Various measures have been implemented to cope with these issues. They range from sediment nourishments to erosion control structures (e.g., Habersack and Piégay, 2007). Our objective is to assess the potential of floodplain lowering and sediment nourishments in mitigating large-scale channel bed incision in engineered rivers affected by climate change, considering a spatial scale of hundreds of kilometres. Our domain of interest is the Rhine River between Bonn, Germany, to Gorinchem, Netherlands. This reach has been extensively channelized during the 18th-20th centuries for improved navigation and flood protection (e.g., Ylla Arbós et al., 2021).","channel bed erosion; erosion mitigation; nourishments; numerical modelling","en","abstract","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:5cb0750c-9946-4bdc-acd4-6f3d8f7e240d","http://resolver.tudelft.nl/uuid:5cb0750c-9946-4bdc-acd4-6f3d8f7e240d","Approaches reproducing suspended sediment transport through vegetation","Liu, J. (TU Delft Water Resources; IHE Delft Institute for Water Education); Bregoli, Francesco (IHE Delft Institute for Water Education); Crosato, A. (TU Delft Environmental Fluid Mechanics; IHE Delft Institute for Water Education); Calvani, Giulio (École Polytechnique Fédérale de Lausanne)","","2024","Working as natural filter, well-designed vegetation schemes have been widely applied to improve the quality of water (Aiona, 2013; Stefanakis, 2015). Proper design, however, requires appropriate physics-based modelling of their filtering capacity. Several theoretical models predicting sediment transport in vegetated flow have been proposed: Baptist (2005); Yang and Nepf (2018); Wu et. al. (2021); Tseng and Tinoco (2021); Yagci and Strom (2022); Wang et. al. (2023). Some of them have been implemented in numerical tools (e.g. Caponi et al., 2022; Li et al., 2022) and in particular in Delft 3D (Deltares, 2014). However, they have been mostly designed and verified based on bedload processes, and their performance for suspended load should be further investigated.
This work compares different approaches on their ability to reproduce the effects of vegetation on suspended solids concentration in two-dimensional models built in Delft3D. The work focuses on emerging vegetation, represented as rigid cylinders, and sediment deposition. Comparisons are based on the ability to reproduce flume experiments available in the literature by analysing both flow field and sediment deposition results.","suspended sediment transport; Delft 3D","en","abstract","","","","","","","","","","","Water Resources","","",""
"uuid:dc5f443d-540c-4451-9e41-529d319cd1e2","http://resolver.tudelft.nl/uuid:dc5f443d-540c-4451-9e41-529d319cd1e2","ResiRiver - Mainstreaming and Upscaling Nature Based Solutions in North West European Rivers","Wilson, Stanford (Rijkswaterstaat); Rem, Nils (Rijkswaterstaat); Schielen, R.M.J. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Rijkswaterstaat); Snoek, Yvo (Rijkswaterstaat)","","2024","River managers today are faced with the challenge of adapting to climate change while also having to sustainably secure all important functions in a healthy river system for society. Nature-based Solutions (NbS) have proven themselves effective across a multitude of contexts; providing integrative approaches for river restoration, conservation and sustainable management, ensuring both climate change adaptation and contribute to climate change mitigation and biodiversity recovery for generations to come. NbS are multi-faceted and more importantly, they are effective when it comes to addressing complex societal challenges (e.g. reducing flood risk, increasing natural values and biodiversity, ecosystem services and human well-being), as they provide a novel, integrative and coherent approach. Despite the significant and rapidly growing base of scientific evidence regarding the effectiveness of NbS in riverine systems management, the actual uptake and application of NbS on a larger (EU) scale is still in its early phase. From where we stand today, a major barrier to the wider uptake and application of NbS in riverine systems remains (a) our limited experience in scaling solutions beyond their local contexts (so called ‘Upscaling’), and (b) make Nbs as a standard work practice within water management organisations throughout North-West Europe (so called ‘Mainstreaming’). Also, our lack of standardised methods for quantitative assessment and monitoring of ecosystem services and benefits related to NbS hinders replication and application at a wider scale.","nature based solutions; assessment frameworks; international cooperation","en","abstract","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:33e4fff4-45ce-4bde-b007-563a274021ea","http://resolver.tudelft.nl/uuid:33e4fff4-45ce-4bde-b007-563a274021ea","Evaluating the impact of Room for the River flood management measures on vegetation health and diversity in the Netherlands via optical remote sensing","Spriggs, A.M.S. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Mosselman, E. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Deltares); Schielen, R.M.J. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Rijkswaterstaat); Stancanelli, L.M. (TU Delft Rivers, Ports, Waterways and Dredging Engineering)","","2024","Recent policy initiatives in Europe emphasize a movement towards nature-based solutions in flood management; however, a quantitative relationship between specific flood management measures and indicators of ecological health and biodiversity is difficult to establish (Penning et al., 2023). In the Netherlands, several studies have been conducted on floodplain vegetation monitoring; however, these studies are primarily focused on monitoring changes to hydraulic roughness for flood risk assessment (Harezlak et al., 2020; Penning & van de Vries, 2020). These works provide an opportunity to expand upon existing research to explicitly connect river management practices with indicators of floodplain biodiversity change in the Netherlands.
In this study, we utilize publicly available geospatial data to identify changes in land use, vegetation classification and spectral indicators of vegetation health at restoration sites associated with the Room for the River (RftR) program in the Netherlands. Completed in 2018, RftR involved over 30 river management projects constructed to reduce flood risk by lowering peak water levels (Mosselman, 2022).
Our objective is to quantify the impact of ecologically focused RftR projects on habitat heterogeneity and river connectivity in the surrounding floodplains.","river restoration; remote sensing; GIS; biodiversity; Normalized Difference Vegetation Index (NDVI); vegetation classification","en","abstract","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:28bfdc09-6454-4fad-acce-26e7fe7ed1e7","http://resolver.tudelft.nl/uuid:28bfdc09-6454-4fad-acce-26e7fe7ed1e7","On the factors governing river morphology with a look on how rivers adapt to climate","Crosato, A. (TU Delft Environmental Fluid Mechanics; IHE Delft Institute for Water Education)","","2024","River morphology can be described at different scales: at the basin scale we distinguish the river network; at the reach scale the planform, the slope and average features, such as the width and bankfull water depth; at the cross-section scale the transverse variations of river bed topography; and at smaller scales we observe bedforms and sediment grains. What are the factors that influence the river mophology at the different scales? Does climate govern these factors and if climate changes, how does the river react?
This review addresses these important questions, focusing at the reach and cross-section scales. Important knowledge gaps are related to the channel width formation, a key factor for river morphology. Several predictors based on field data relate the equilibrium width to bankfull discharge, sediment size, vegetation and bank resistance. However, it is not clear if the river width also depends on the conditions at the start of the morphological process. An example are rivers that adapt their morphology after their water and sediment discharge regimes have been altered by an external factor, such as a dam of a change in climate. Does the morphology of these rivers depend also on their previous width?","river morphology; channel width; adaptation to climate","en","abstract","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:af2cf549-dd3d-4ee4-91be-722551118409","http://resolver.tudelft.nl/uuid:af2cf549-dd3d-4ee4-91be-722551118409","Towards a robust and well-functioning Rhine River system that can sustainably provide its geo-ecosystem services","Klijn, F. (TU Delft Policy Analysis; Deltares)","","2024","The policy programme Integrated River Management (IRM) aims to anticipate climate change and to redress the negative consequences of earlier river engineering interventions. Its objective is to first and foremost ensure a well-functioning river system that can provide its essential ‘public’ geo-ecosystem services: safe discharge of floods, reliable freshwater supply, reliable waterways to the hinterland, and good conditions for aquatic and terrestrial ecosystems in the floodplains and beyond. Challenges, however, relate to the changing discharge regime resulting from climate change, and to the conflicting requirements of the various river functions and values. These pose real dilemmas about when to act, how to act, which function or value to support and which one to curb.","Robustness; Discharge capacity; Transformation","en","abstract","","","","","","","","","","","Policy Analysis","","",""
"uuid:810a8c53-abc8-4893-b114-abee5715073d","http://resolver.tudelft.nl/uuid:810a8c53-abc8-4893-b114-abee5715073d","The climate barge: Heritage and climate adaptation in the Dutch province of South-Holland","Mostert, E. (TU Delft Water Resources)","","2024","In the project Heritage uncovered; Tow barge canals in a water management context, the future value of tow barge canals for climate adaptation has been studied. The project focused on the area between the cities Leiden, The Hague, Delft, Rotterdam and Gouda, with a surface area of km2, and the tow barge canals the Vliet, the Schie, the Gouwe and the Old Rhine. Until 900 CE the areas was mostly peat swamp. Since then, it has been drained for agriculture. This has resulted in economic growth and the development of cities in the 13th Century. A side effect of drainage was land subsidence. In addition, peat was mined to supply the cities with fuel. To limit waterlogging, large drainage canals were dug, such as the Vliet and the Schie. In the 17th Century, many of these were modified to function as tow barge canals connecting the major cities.
It is expected that the water management challenges in the area will increase as a result of climate change. According to the climate scenarios for 2100 of the Royal Meteorological Institute, both heavy rainstorms and periods without any rainfall will become more common. On top of this, there are plans to build many new houses.
To prevent an increase in flood and drought problems, more temporary water storage can be created, but no less than 34 mln m3 of additional storage would be needed. 7.5 mln m3 additional storage can be created in the different polders, primarily to cope with peak rainfall events, while east of the town of Zoetermeer a new lake with 26.5 mln m3 of temporary storage can be created to supply water in drought periods, called the Bent lake (Bentmeer). Assuming 2 m difference between the highest and the lowest water level, the Bent lake would need to have a surface area of 13.3 km2. It can offer excellent opportunities for recreation and nature.
To transport water in and out of the Bent lake, a connection to the Rotte river in the south and the Old Rhine (Oude Rijn) in the north has to be made. This would restore an old shipping route. For the connection to the Old Rhine three options have been explored and for one of these a spatial plan has been made. In this option the Bent lake is connected to the existing Benthuizer canal (Benthuizervaart) and the Benthuizer canal is connected via a new canal to the existing Hoogeveense canal (Hoogeveense vaart), (see figures 15 and 16). Along parts of the new canal futuristic “green” appartements will be built with a view either on the canal or over the surrounding polders. To limit height differences for boating, the new canal will be constructed above the level of the polder. The new apartment buildings along the canal will also be built at a higher level, which will make them less vulnerable to flooding (see figure 1).
In all options the old tow barge canals are essential for transporting water to and from the Bent lake and discharging excess water onto the main rivers and the North Sea. In addition, they are a good entry point for telling the history of the landscape and reflecting on possible futures. It is proposed to construct a tow path along the new canal and make a replica of an original tow barge. This barge will be called the “Climate Barge” (Klimaatschuit) and can be used as a floating exhibition space and a location for future discussions.
The proposals in this report have not yet been developed in detail and the future is still very uncertain. Yet, we cannot wait until there is certainty. If sooner or later large-scale temporary water storage in this part of the country will be needed, space for this has to be reserved quite soon. The costs will be high, but the costs of inaction will be high too. And it offers new opportunities.
4+/3+ and Eu3+/2+ charge transition levels (CTLs) is the most important parameter in constructing vacuum referred binding energy diagrams (VRBEs) with all the lanthanide CTLs with respect to the vacuum level of energy. The parameter is difficult to determine from experiment and the aim of this work is to establish a method to estimate the U-value from the average electronegativity of the cations in the compound. Since the U-value is controlled by the same physical processes, i.e., covalence and anion polarizability, as the centroid shift ϵc of the Ce3+ 5d configuration, one may estimate the U-value from that centroid shift. That method provides already good values for U for about 175 different compounds. Those U-values are compared with the average cation electronegativity χav, and relations will be established from which the U-value can be estimated with about ±0.1 eV accuracy from just the composition of the compound. It can be applied to all types of stoichiometric inorganic compounds like the halides (F, Cl, Br, I), chalcogenides (O, S, Se), and nitrides (N). The U-value complemented with the bandgap and the energy needed for electron transfer from the valence band top to a trivalent lanthanide dopant is then sufficient to construct a VRBE diagram with all lanthanide levels with respect to the vacuum level and the host valence and conduction bands.","Ce centroid shift; Charge transition levels; Electronegativity; Electronic structure; Lanthanides; VRBE-schemes","en","journal article","","","","","","","","","","","RST/Luminescence Materials","","",""
"uuid:c224e646-2ccd-47bc-8718-1224caf447b1","http://resolver.tudelft.nl/uuid:c224e646-2ccd-47bc-8718-1224caf447b1","An efficient bilinear interface reconstruction algorithm and consistent multidimensional unsplit advection scheme for accurate capturing of highly-curved interfacial shapes on structured grids","van der Eijk, M. (TU Delft Ship Hydromechanics); Wellens, P.R. (TU Delft Ship Hydromechanics and Structures)","","2024","A new bilinear interface reconstruction algorithm (BLIC) is presented to capture highly-curved interfaces more accurately on structured grids without a significant increase in computational costs compared to the standard piecewise linear interface calculation (PLIC) methods. The new reconstruction algorithm uses the initial PLIC segment and improves continuity of the interface using an averaging method. A curvature-weighted method improves the repositioning of the linear segments. A new unsplit donating quadrant advection (DQA) scheme is introduced that is conservative and can create consistency with the momentum flux for two-phase flow models with a staggered MAC arrangement of variables within a grid cell. The consistent discretization of the fluxes prevents spurious interface velocities, negative densities, and instabilities. Standard 2D test cases and benchmarks demonstrate the performance of the BLIC and the DQA scheme, showing high accuracy and low costs compared to other available methods.","Bilinear interface reconstruction; Interface capturing; Multiphase flow; Unsplit advection scheme; Volume of fluid","en","journal article","","","","","","","","","","","Ship Hydromechanics","","",""
"uuid:13f9b1f0-2a1b-4147-a051-66ac364f1c11","http://resolver.tudelft.nl/uuid:13f9b1f0-2a1b-4147-a051-66ac364f1c11","Improving mechanical properties and sustainability of high-strength engineered cementitious composites (ECC) using diatomite","Zhu, Xuezhen (Central South University China); Zhang, Minghu (Central South University China); Shi, Jinyan (Central South University China); Weng, Yiwei (The Hong Kong Polytechnic University); Yalçınkaya, Çağlar (Dokuz Eylul University); Šavija, B. (TU Delft Materials and Environment)","","2024","High-strength engineered cementitious composites (ECC) typically require higher cement content, which is negative from the sustainability point of view. To alleviate this problem, herein a low-cost and eco-friendly high-strength ECC (with a compressive strength of over 100 MPa) was developed, and diatomite was used to replace a small amount of cement. An appropriate amount of diatomite was found to improve the compressive strength, tensile strength and first cracking strength of ECC, but at the expense of part of the strain capacity (still all higher than 2.9%). Furthermore, the high pozzolanic activity and specific surface area of diatomite also increased the autogenous shrinkage, but reduced the drying shrinkage of ECC due to its internal curing effect. The incorporation of diatomite improved the pore structure of ECC, consumed more Ca(OH)2, and enhanced the hydration degree of the mixture. In the end, the economic and environmental benefits of diatomite-modified ECC were also evaluated, and the cost, non-renewable energy demand, and global warming potential of ECC with 3% diatomite were reduced compared to plain ECC by 12.9, 15.1, and 13.3%, respectively. The developed high-strength ECC is therefore a low-cost and eco-friendly alternative to the traditional one.","Diatomite; Engineered cementitious composites (ECC); High-strength; Sustainability assessment; Tensile properties","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-02","","","Materials and Environment","","",""
"uuid:a67ddc88-90a3-4cd6-8da1-f40d630644f3","http://resolver.tudelft.nl/uuid:a67ddc88-90a3-4cd6-8da1-f40d630644f3","Investigating the Role of Executive Intrafirm Alumni Networks in Top Management Fraud: Multilevel Study in China's Construction Industry","Wang, Ran (Hunan University); Wang, Tongbing (Hunan University); Lee, Chia-Jung (Tunghai University); Liu, Zhengxuan (TU Delft Design & Construction Management; Hunan University); Zhang, G. (Hunan University)","","2024","To explore factors that influence the likelihood of committing fraud in the construction industry, this study concentrated on senior executives and tested whether some characteristics at the individual and firm levels have impacts on the likelihood of fraud committed by top management. Based on social network theory, this study first proposes that intrafirm alumni networks may increase the probability of senior executives engaging in corrupt behavior. Then the study explored whether the effect of executives' alumni networks on their wrongdoings is influenced by external and internal corporate governance measures. To verify the hypotheses, this study collected data on 2,017 senior executives from 118 construction companies in China from 2013 to 2021. Because of the multilevel structure of the data, hierarchical linear modeling was used. The results show that alumni networks have a significant positive effect on top management fraud. The effect is weakened by external auditing, altered by board independence, and strengthened by the size of the board of directors and the size of the supervisory board. This multilevel research contributes to advancing the understanding of managers' fraudulent behavior within an organization and extends the literature on social networks and corporate governance in the construction industry.","Alumni networks; Corporate governance; Hierarchical linear modeling; Social networks; Top management fraud","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-13","","","Design & Construction Management","","",""
"uuid:6b9bbc73-571d-4f60-8ddd-1a2f720879f5","http://resolver.tudelft.nl/uuid:6b9bbc73-571d-4f60-8ddd-1a2f720879f5","Imperfection-induced internal resonance in nanotube resonators","Belardinelli, P. (Università Politecnica delle Marche); Lenci, S. (Università Politecnica delle Marche); Alijani, F. (TU Delft Dynamics of Micro and Nano Systems)","","2024","Through molecular dynamics simulations, we demonstrate the possibility of internal resonances in single-walled carbon nanotubes. The resonant condition is engineered with a lack of symmetry in the boundary condition and activated by increasing the energy exchange with a coupled thermal bath. The critical temperature threshold for initiating modal interaction is found to be chirality-dependent. By applying the proper orthogonal decomposition algorithm to molecular dynamics time responses, we show how the thermal fluctuations influence the vibrational behaviour of the nanotube leading to both flexural–flexural and flexural–longitudinal resonances. Understanding the interaction between nanotube resonators and the thermal bath is crucial for designing and optimizing their performance for various nanoscale sensing, actuation, and signal processing applications.","Carbon nanotube; Imperfect boundary conditions; Internal resonance; Molecular dynamics; Thermoelasticity","en","journal article","","","","","","","","","","","Dynamics of Micro and Nano Systems","","",""
"uuid:a79712b3-9716-42bb-b01a-c657a7b34369","http://resolver.tudelft.nl/uuid:a79712b3-9716-42bb-b01a-c657a7b34369","How manoeuvre information via auditory (spatial and beep) and visual UI can enhance trust and acceptance in automated driving","Kim, S. (TU Delft Human Information Communication Design); van Egmond, R. (TU Delft Human Information Communication Design); Happee, R. (TU Delft Intelligent Vehicles)","","2024","In conditionally automated driving (SAE level 3), drivers may take their eyes off the road but will still need to be ready to take control and will, therefore, benefit from information on automation. This study aims to investigate the effectiveness of automation manoeuvre information provided through spatial sound, traditional notification sound (beep), and a visual interface. Spatial sounds were designed differentiating four distinct driving manoeuvres: overtaking a leading car, slowing down, turning right, and passing a roundabout. The notification sound consisted of one beep being identical for all manoeuvres. The visual interface showed the automation mode with an image and manoeuvre information with text and images. The impact of these interfaces on trust, workload, acceptance, situation awareness, and sense of control was evaluated with questionnaires and visual attention was evaluated with eye tracking while participants engaged in a visual-motor secondary task in a driving simulator. The results indicate that, with all interfaces tested, manoeuvre information enhances trust, acceptance, situation awareness, and sense of control, without significantly affecting the overall workload. These benefits were more profound, adding auditory information and differed marginally between the traditional notification and the spatial sound, as the effectiveness of the different auditory interface types varied depending on the specific manoeuvre. Findings highlight the importance of designing user interfaces for automation manoeuvre information using auditory cues to improve the user experience in automated driving.","Automated vehicles; Human-Machine Interaction; Trust; Acceptance; Sound design","en","journal article","","","","","","","","","","","Human Information Communication Design","","",""
"uuid:6a549ef8-9f86-4151-8aee-448ea6ad4c30","http://resolver.tudelft.nl/uuid:6a549ef8-9f86-4151-8aee-448ea6ad4c30","The effect of working fluid and compressibility on the optimal solidity of axial turbine cascades","Tosto, F. (TU Delft Flight Performance and Propulsion); Pini, M. (TU Delft Flight Performance and Propulsion); Colonna, Piero (TU Delft Flight Performance and Propulsion)","","2024","The blade solidity, namely the blade chordtopitch ratio, largely affects the fluiddynamic performance of turbomachinery. For turbomachines operating with air or steam, the optimal value of the solidity which maximizes the efficiency is estimated with empirical correlations such as the ones proposed by Zweifel (1945) and Traupel (1966). However, if the turbomachine operates with unconventional fluids, the accuracy of these correlations becomes questionable. Examples of such working fluids are the nonideal (dense) vapors of organic compounds (e.g., hydrocarbons, siloxanes) used to operate organic Rankine cycle (ORC) power systems. This study investigates the effect of both the working fluid and the flow compressibility on the optimum pitchtochord ratio of turbine stages. A first principle model for the profile losses is developed for this purpose. Charts providing the optimal pitchtochord ratio for unconventional turbine stages are then provided. Numerical simulations of the flow over a turbine stator cascade have been conducted to validate the model results and evaluate the influence of both working fluid, flow compressibility, and solidity value on the loss breakdown. The results show that the optimal solidity of turbine cascades value significantly increases with the flow compressibility. Therefore, models providing the optimal solidity based on the estimate of passage loss only are not suited for unconventional turbines.","","en","conference paper","","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:dc1f4148-c91f-49ae-818c-ef7d4ed17212","http://resolver.tudelft.nl/uuid:dc1f4148-c91f-49ae-818c-ef7d4ed17212","Towards a framework for point-cloud-based visual analysis of historic gardens: Jichang Garden as a case study","Peng, Y. (TU Delft Landscape Architecture); Zhang, Guanting (Nanjing Tech University); Nijhuis, S. (TU Delft Landscape Architecture); Agugiaro, G. (TU Delft Urban Data Science); Stoter, J.E. (TU Delft Urban Data Science)","","2024","Historic gardens, regarded as a significant genre of cultural heritage, encapsulate the enduring essence of bygone eras while concurrently transcending temporal boundaries to resonate with the present and future. These gardens provide us vitality and inspiration, holding a collective repository of human memory and serving as a testament to our shared heritage. However, like landscapes, gardens constantly change through natural processes and human interventions. How can we preserve these gardens, though changes are unavoidable? Spatial and visual characteristics are the gardens' essential characteristics, and point-cloud (LiDAR) technologies are powerful tools to reveal and analyze gardens’ spatial-visual relationships and characteristics. Therefore, this paper aims to present a point-cloud-based approach to identifying spatial-visual design principles and making them operational to protect and develop historic gardens. Additionally, several methods have been proposed in this research, including (a) a voxel-based method to transfer points into a solid model for GIS-based computation, (b) a novel method to analyze the field of view (FOV), and (c) a systemic framework to reveal historic gardens’ spatial-visual characteristics based on the voxelized model. Jichang Garden, a historic garden in Wuxi, China, known for its visual design and spatial arrangement, has been selected as a case study to showcase how to apply the methods proposed by this paper. The findings include the design principles for the water body, the arrangement for a route, and the planting strategies of the garden. The conservational strategies have been formed based on the findings, and the appliable potentials and limitations of the methods have also been discussed.","Spatial analysis; Jichang Garden; Heritage gardens; LiDAR; GIS","en","journal article","","","","","","","","","","","Landscape Architecture","","",""
"uuid:9062a160-7556-44c3-a06c-7579961da0a4","http://resolver.tudelft.nl/uuid:9062a160-7556-44c3-a06c-7579961da0a4","Unveiling complexity of hydrogen integration: A multi-faceted exploration of challenges in the Dutch context","Hasankhani, M. (TU Delft Design for Sustainability); van Engelen, J.M.L. (TU Delft Design for Sustainability); Celik, S (TU Delft Methodologie en Organisatie van Design); Diehl, J.C. (TU Delft Design for Sustainability)","","2024","As the transition to sustainable energy intensifies, hydrogen emerges as a pivotal medium in mitigating climate change and improving energy security. While its applicability across various sectors is undeniable, its integration into established energy systems presents multifaceted challenges. This study investigates the complexities of integrating hydrogen into the Netherlands' energy systems. Beyond technological advancements, the successful design and rollout of a hydrogen supply chain require coordination and collaboration among a myriad of stakeholders. Through a mixed-methods approach, this study combines findings from a broad literature review, policy document analyses, evaluation of 59 field projects, and engaging dialogues with 33 key stakeholders from different sectors. This investigation led to the identification and categorization of key players in the Dutch hydrogen sector, revealing their interconnected roles and the challenges encountered in the hydrogen integration process. The study further categorized the identified challenges faced by stakeholders into five core domains: technical, infrastructural (including supply chain), socioeconomic, environmental, and institutional, with associated factors. Prominent challenges include transportation infrastructure upgrades, high initial costs and scalability, effective storage methods, safety and cybersecurity measures, storage and distribution infrastructure, security of supply, and public acceptance. This study contributes to the hydrogen integration discourse, offering insights for academics, industry, and policymakers. Its detailed stakeholder analysis, holistic categorization of challenges across five domains, and a stakeholder-centric approach grounded in real-world dialogues offer applicable frameworks beyond its primary context. In this vein, it guides future research and decisions, and its approach is adaptable for different regions or sectors, emphasizing comprehensive transition strategies.","Hydrogen infrastructure; Hydrogen supply chain; Sectoral distribution shifts; Stakeholder analysis; Stakeholder coordination; Energy policy","en","journal article","","","","","","","","","","","Design for Sustainability","","",""
"uuid:f18ce335-ce3c-40ee-a7bd-ccce8e5a1481","http://resolver.tudelft.nl/uuid:f18ce335-ce3c-40ee-a7bd-ccce8e5a1481","Emergency response in cascading scenarios triggered by natural events","Ricci, Federica (University of Bologna); Yang, M. (TU Delft Safety and Security Science); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven); Cozzani, Valerio (University of Bologna)","","2024","Emergency response is a procedural safety barrier of paramount importance for the mitigation of fire scenarios and the prevention of escalation. However, in Natech scenarios, emergency response may be affected by the natural event impacting the site. Indeed, when contrasting Natech accidents, emergency responders have to face both the natural event and the cascading technological scenario. Despite the criticality of the issue, limited attention was devoted to date to the analysis of emergency response in cascading sequences triggered by natural events. The present study provides a novel and technically sound methodology to assess the performance of emergency response and the required intervention time in Natech scenarios. An expert survey combined with a Bayesian Network model was used to assess the performance of the emergency response. The routing and setup phases were identified as those mostly affected by natural events. Monte Carlo simulations were used to obtain baseline data and specific probability distributions for the time required to carry out the emergency response considering the factors that may hinder the response during natural events. In Natech accidents, the time for effective mitigation resulted higher of at least a factor 2 with respect to that expected in the case of conventional accidents. The methodology developed may be used to support the improvement of the emergency management of Natech scenarios, allowing for a detailed definition of site-specific emergency response plans. Moreover, the results may be used to provide a more accurate assessment of the fire-driven escalation probability in Natech events.","Cascading events, Natech, Quantitative risk assessment, Bayesian Network, Monte Carlo simulation; Emergency response","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:6047e0c7-382a-47c3-ad09-2eecf2115de5","http://resolver.tudelft.nl/uuid:6047e0c7-382a-47c3-ad09-2eecf2115de5","Evaluating the choice of radial basis functions in multiobjective optimal control applications","Zatarain Salazar, J. (TU Delft Policy Analysis); Kwakkel, J.H. (TU Delft Policy Analysis); Witvliet, Mark (Axians)","","2024","Evolutionary Multi-Objective Direct Policy Search (EMODPS) is a prominent framework for designing control policies in multi-purpose environmental systems, combining direct policy search with multi-objective evolutionary algorithms (MOEAs) to identify Pareto approximate control policies. While EMODPS is effective, the choice of functions within its global approximator networks remains underexplored, despite their potential to significantly influence both solution quality and MOEA performance. This study conducts a rigorous assessment of a suite of Radial Basis Functions (RBFs) as candidates for these networks. We critically evaluate their ability to map system states to control actions, and assess their influence on Pareto efficient control policies. We apply this analysis to two contrasting case studies: the Conowingo Reservoir System, which balances competing water demands including hydropower, environmental flows, urban supply, power plant cooling, and recreation; and The Shallow Lake Problem, where a city navigates the trade-off between environmental and economic objectives when releasing anthropogenic phosphorus. Our findings reveal that the choice of RBF functions substantially impacts model outcomes. In complex scenarios like multi-objective reservoir control, this choice is critical, while in simpler contexts, such as the Shallow Lake Problem, the influence is less pronounced, though distinctive differences emerge in the characteristics of the prescribed control strategies.","Direct policy search; Global approximators; Many Objective Evolutionary Algorithms; Water resources management","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:d3529293-7b5d-4265-9816-41c226eb9685","http://resolver.tudelft.nl/uuid:d3529293-7b5d-4265-9816-41c226eb9685","Do personality traits influence the user's behavioral intention to adopt and use Open Government Data (OGD)? An empirical investigation","Rizun, Nina (Politechnika Gdanska); Alexopoulos, Charalampos (University of the Aegean); Saxena, Stuti (Graphic Era University); Kleiman, F. (TU Delft Information and Communication Technology); Matheus, R. (TU Delft Information and Communication Technology)","","2024","The academic interest in the Open Government Data (OGD) domain has been burgeoning over the years. Conceding that the prime focus of an OGD initiative is its further re-use for value creation and innovation by stakeholders, the present study seeks to underscore the role of HEXACO personality traits on behavioral intention (BI) to adopt and use OGD in developing countries' context. We investigate the direct, indirect, and moderating effects of HEXACO personality traits provide a better understanding of how and to what extent personality traits influence future behavioral intention to use OGD. The results demonstrate that Trust and Performance Expectancy are positive predictors of BI to adopt and use OGD. Users with higher Openness to Experience tend to have higher Effort and Performance Expectancy; are characterized by exposure to Social Influence; have higher level of Trust and positive experience of Facilitating Conditions and Information Quality. Agreeable people are more likely to Voluntarily Use OGD. Conscientiousness enhances the individual's perception of OGD quality-related factors. Excessive Emotionality affects negative perception to System and Information Quality issues. Honesty–Humility and Extraversion are able to maintain the effect of OGD Information Quality and Trust on users' BI. Our findings could be useful for practitioners to level the divergence between actual and potential use of OGD by considering the user's personality traits.","HEXACO; OGD; Open Government Data; Personality traits; Technology adoption; UTAUT","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-30","","","Information and Communication Technology","","",""
"uuid:86e4fe80-a217-423d-b2ea-dcf1e88fc0bd","http://resolver.tudelft.nl/uuid:86e4fe80-a217-423d-b2ea-dcf1e88fc0bd","Air quality forecasting of along-route ship emissions in realistic meteo-marine scenarios","Orlandi, Andrea (Consorzio LaMMA); Calastrini, Francesca (IMAMOTER - C.N.R. Sensors and Nanomaterials Laboratory); Kalikatzarakis, Miltiadis (University of Strathclyde); Guarnieri, Francesca (Consorzio LaMMA); Busillo, Caterina (Consorzio LaMMA); Coraddu, A. (TU Delft Ship Design, Production and Operations)","","2024","This study introduces a novel framework of metocean prediction and ship performance models that integrate multiple layers of modeling to evaluate the environmental impact of ship emissions. It enables scenario simulations that assess a ship's performance, estimates pollutant emissions, and simulate the fate of these pollutants in the atmosphere. The study analyzes the fate of NOx, SO2, and PM10 pollutants in the atmosphere using spatially distributed concentration maps. It provides a comprehensive approach to assessing the environmental effects of ships and their emissions and contributes to the field of environmental impact assessment. Case studies are presented to demonstrate the framework's functionalities, evaluating the interrelationships between adverse meteo-marine conditions, pollutant emissions, and resulting atmospheric diffusion characteristics.","Air quality modeling; Seakeeping; Ship emissions; Ship performance modeling","en","journal article","","","","","","","","","","","Ship Design, Production and Operations","","",""
"uuid:8455eb64-fe10-4196-8c60-14f16c292381","http://resolver.tudelft.nl/uuid:8455eb64-fe10-4196-8c60-14f16c292381","3-D induction log modelling with integral equation method and domain decomposition pre-conditioning","Saputera, D. H. (University of Bergen); Jakobsen, M. (University of Bergen); van Dongen, K.W.A. (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Van Dongen goup); Jahani, N. (NORCE Norwegian Research Centre AS); Eikrem, K. S. (NORCE Norwegian Research Centre AS); Alyaev, S. (NORCE Norwegian Research Centre AS)","","2024","The deployment of electromagnetic (EM) induction tools while drilling is one of the standard routines for assisting the geosteering decision-making process. The conductivity distribution obtained through the inversion of the EM induction log can provide important information about the geological structure around the borehole. To image the 3-D geological structure in the subsurface, 3-D inversion of the EM induction log is required. Because the inversion process is mainly dependent on forward modelling, the use of a fast and accurate forward modelling tool is essential. In this paper, we present an improved version of the integral equation (IE) based modelling technique for general anisotropic media with domain decomposition pre- conditioning. The discretized IE after domain decomposition equals a fixed-point equation that is solv ed iterativ ely with either the block Gauss-Seidel or Jacobi pre-conditioning. Within each iteration, the inverse of the block matrix is computed using a Krylov subspace method instead of a direct solver. An additional reduction in computational time is obtained by using an adaptive relative residual stopping criterion in the iterativ e solv er. Using this domain decomposition scheme, numerical experiments show computation time reductions by factors of 1.97-2.84 compared to solving the full-domain IE with a GMRES solver and a contraction IE pre- conditioner. Additionally, the reduction of memory requirement for covering a large area of the induction tool sensitivity enables acceleration with limited GPU memory. Hence, we conclude that the domain decomposition method is improving the efficiency of the IE method by reducing the computation time and memory requirement.","Electromagnetic theory; Numerical modelling; Numerical solutions","en","journal article","","","","","","","","","","","ImPhys/Medical Imaging","","",""
"uuid:8a757769-7f9a-4d2f-a7ae-1ed7369e90fd","http://resolver.tudelft.nl/uuid:8a757769-7f9a-4d2f-a7ae-1ed7369e90fd","Modelling the formation of peer-to-peer trading coalitions and prosumer participation incentives in transactive energy communities","Zhang, Ying (Student TU Delft; Centrum Wiskunde & Informatica (CWI)); Robu, Valentin (Centrum Wiskunde & Informatica (CWI); Eindhoven University of Technology; Princeton University); Cremers, S.A. (TU Delft Intelligent Electrical Power Grids; Centrum Wiskunde & Informatica (CWI)); Norbu, Sonam (University of Glasgow); Couraud, Benoit (University of Glasgow); Andoni, Merlinda (University of Glasgow); Flynn, David (University of Glasgow); Poor, H. Vincent (Princeton University)","","2024","Peer-to-peer (P2P) energy trading and energy communities have garnered much attention over in recent years due to increasing investments in local energy generation and storage assets. Much research has been performed on the mechanisms and methodologies behind their implementation and realisation. However, the efficiency to be gained from P2P trading, and the structure of local energy markets raise many important challenges. To analyse the efficiency of P2P energy markets, in this work, we consider two different popular approaches to peer-to-peer trading: centralised (through a central market maker/clearing entity) vs. fully decentralised (P2P), and explore the comparative economic benefits of these models. We focus on the metric of Gains from Trade (GT), given optimal P2P trading schedule computed by a schedule optimiser. In both local market models, benefits from trading are realised mainly due to the diversity in consumption behaviour and renewable energy generation between prosumers in an energy community. Both market models will lead to the most promising P2P contracts (the ones with the highest Gains from Trade) to be established first. Yet, we find diversity decreases quickly as more peer-to-peer energy contracts are established and more prosumers join the market, leading to significantly diminishing returns. In this work, we aim to quantify this effect using real-world data from two large-scale smart energy trials in the UK, i.e. the Low Carbon London project and the Thames Valley Vision project. Our experimental study shows that, for both market models, only a small number of P2P contracts i.e. less than 10% of the possible P2P contracts are required to achieve the majority of the maximal potential Gains from Trade. Similarly, only a fraction of prosumers are required to participate in energy trading to realise significant GT; namely we found that 60% of the maximal GT can be realised with only 30% of prosumers’ participation, with the percentage of maximal GT reaching 80% when participation increases to 50% of prosumers. Finally, we study the effect that diversity in consumption profiles has on overall trading potential and dynamics in an energy community. We show that in a community with a DF(load diversity factor) = 1, 80% of potential maximal GT can be achieved by 10% of prosumers engaging in P2P trading, while in a community with DF = 1.5, it is beneficial for 40% of the prosumers to trade.","Peer-to-peer trading; Energy community; Negotiation","en","journal article","","","","","","","","","","","Intelligent Electrical Power Grids","","",""
"uuid:71c7c81d-b1c0-49ef-9b5f-492a481ea42c","http://resolver.tudelft.nl/uuid:71c7c81d-b1c0-49ef-9b5f-492a481ea42c","Glare-based control strategy for Venetian blinds in a mixed-use conference space with fully glazed facades","Theodoropoulou, P. (TU Delft Civil Engineering & Geosciences); Brembilla, E. (TU Delft Environmental & Climate Design); Schipper, H.R. (TU Delft Applied Mechanics); Louter, P.C. (TU Delft Applied Mechanics)","","2024","Smart buildings are equipped with automated control systems that provide a comfortable indoor environment, aiming simultaneously at energy savings. Control systems for shading devices applied in practice are mostly driven by a rule-based approach, that is usually tested under simplified conditions and hence its effectiveness in complex real-life cases is questionable. The present study develops an optimized glare-based control strategy for Venetian blinds in a real-life open-space building with totally transparent facades. The research is based on the case study of the Co-Creation Center at the TU Delft campus, which can host three different types of events: presentations, meetings and workshops. The control strategy is developed within Grasshopper, a tool for parametric and optimization problems. Radial Basis Function Optimization (RBFOpt) is utilized for the computation of the optimal blinds’ states. Within the developed control strategy, cylindrical illuminance (Ecyl) is used as a glare index, giving the opportunity to evaluate its performance. Results show that the optimized algorithm can improve the existing visual conditions in the building by an average of 80% for all activity types, although it leads to an average increase of 7% of the time when electric lighting is needed, in comparison to the current rule-based control. Finally, Ecyl displayed an overall agreement of 92.5% with DGP-based glare assessments, proving that in spaces with multiple windows and uncertain occupants’ view direction, a view-independent index can predict glare risks as well as a state-of-the-art view-dependent metric.","Living lab; Fully glazed facades; Control strategy; Optimization; Cylindrical illuminance","en","journal article","","","","","","","","","Civil Engineering & Geosciences","","Environmental & Climate Design","","",""
"uuid:777c8d37-6367-455e-80fa-1905fa6f6940","http://resolver.tudelft.nl/uuid:777c8d37-6367-455e-80fa-1905fa6f6940","Regression analysis for container ships in the early design stage","Rinauro, B. (Università degli Studi di Napoli Federico II); Begovic, E. (Università degli Studi di Napoli Federico II); Mauro, F. (TU Delft Ship Design, Production and Operations; Sharjah Maritime Academy); Rosano, G. (Università degli Studi di Napoli Federico II)","","2024","The seaway trade market has expanded in the last years and container ship dimensions are constantly increasing for higher cargo capacity. In the early design stage, main dimensions are usually determined based on an existing ship database from which regression formulas are derived. In the present paper, a database of 260 non-sister container ships built from 1979 to 2022, representing 20% of the world fleet, has been considered to derive and compare different types of regressions. Simple regressions have been developed and compared with equivalent formulations available in literature, proving better approximations of the trends. The study has been further extended by multivariable regressions and forest tree algorithms, which allow the use of more than one independent variable and provide a better fitting compared to simple regressions. Forest tree regressions return the highest values of fitting coefficients, but the technique is not of easy application due to the absence of mathematical expressions. The main contribution is the updated set of simple and multivariable regression formulas which have a higher goodness of fit than previous works and can be easily employed by designers in the early design stage and in multi-attribute design procedures.","Container ships; Database statistics; Forest trees; Multivariable regressions; Ship design; Simple regressions","en","journal article","","","","","","","","","","","Ship Design, Production and Operations","","",""
"uuid:50f3bf57-dab0-4cb5-bb2f-d31759e5c62f","http://resolver.tudelft.nl/uuid:50f3bf57-dab0-4cb5-bb2f-d31759e5c62f","Efficiency of InN/InGaN/GaN Intermediate-Band Solar Cell under the Effects of Hydrostatic Pressure, In-Compositions, Built-in-Electric Field, Confinement, and Thickness","Abboudi, Hassan (University of Sidi Mohamed Ben Abdullah); El Ghazi, Haddou (Hassan II University of Casablanca; University of Sidi Mohamed Ben Abdullah); En-nadir, Redouane (University Sidi Mohammed Ben Abdellah); Basyooni, Mohamed A. (TU Delft Dynamics of Micro and Nano Systems; National Research Institute of Astronomy and Geophysics; Selçuk University); Jorio, Anouar (University of Sidi Mohamed Ben Abdullah); Zorkani, Izeddine (University of Sidi Mohamed Ben Abdullah)","","2024","This paper presents a thorough numerical investigation focused on optimizing the efficiency of quantum-well intermediate-band solar cells (QW-IBSCs) based on III-nitride materials. The optimization strategy encompasses manipulating confinement potential energy, controlling hydrostatic pressure, adjusting compositions, and varying thickness. The built-in electric fields in (In, Ga)N alloys and heavy-hole levels are considered to enhance the results’ accuracy. The finite element method (FEM) and Python 3.8 are employed to numerically solve the Schrödinger equation within the effective mass theory framework. This study reveals that meticulous design can achieve a theoretical photovoltaic efficiency of quantum-well intermediate-band solar cells (QW-IBSCs) that surpasses the Shockley–Queisser limit. Moreover, reducing the thickness of the layers enhances the light-absorbing capacity and, therefore, contributes to efficiency improvement. Additionally, the shape of the confinement potential significantly influences the device’s performance. This work is critical for society, as it represents a significant advancement in sustainable energy solutions, holding the promise of enhancing both the efficiency and accessibility of solar power generation. Consequently, this research stands at the forefront of innovation, offering a tangible and impactful contribution toward a greener and more sustainable energy future.","IBSC; III-nitrides; efficiency; semi-graded potential; built-in field; thickness","en","journal article","","","","","","","","","","","Dynamics of Micro and Nano Systems","","",""
"uuid:8ce650e1-8ae9-46d2-a7d0-08ed058937da","http://resolver.tudelft.nl/uuid:8ce650e1-8ae9-46d2-a7d0-08ed058937da","Infrared temperature measurements on fast moving targets: A novel calibration approach","Sisti, Manuela (University of Oxford); Falsetti, C. (TU Delft Fluid Mechanics); Beard, Paul F. (University of Oxford)","","2024","In this study, an infrared system is developed for accurate measurements of surface temperature and heat transfer on fast moving targets. The system was designed for the Oxford Turbine Research Facility, a world-leading experimental facility delivering highly engine representative, scalable heat transfer results for aerospace research. Infrared thermography is employed to acquire temperature maps of high-pressure turbine blades, allowing assessment of surface thermal conditions including heat transfer coefficient, adiabatic wall temperature, Nusselt number, cooling effectiveness, and metal effectiveness. Achieving accurate infrared thermography measurements in rotating turbomachinery experimental conditions is arduous due to reflections from the surroundings, low emissivity of metallic parts, and motion blur resulting from high speed. To overcome these challenges, calibration procedures were developed against a traceable standard using a bespoke steady experimental facility. A method to determine the reflected temperature from surroundings was also validated. Correction for all measurement disturbances is demonstrated to within the accuracy of the primary measurement thermocouple. Finally, the developed calibration method was validated on a fast-moving rotating geometry demonstrating accurate correction for all measurement disturbances, without the need for an in situ calibration. A detailed uncertainty analysis for each calibration step is also presented.","High-speed target; Infrared thermography; Measurement advancements; Turbomachinery","en","journal article","","","","","","","","","","","Fluid Mechanics","","",""
"uuid:3a68b23c-57d5-46f6-83e7-61ef990558b6","http://resolver.tudelft.nl/uuid:3a68b23c-57d5-46f6-83e7-61ef990558b6","De klimaatschuit: Trekvaarten, klimaatadaptatie en ruimtelijke ontwikkeling in Zuid-Holland","Mostert, E. (TU Delft Water Resources)","","2024","In het project Erfgoed onthult; Trekvaarten binnen het waterverband is gekeken naar de toekomstwaarde van trekvaarten voor klimaatadaptatie. Het project richt zich specifiek op het gebied tussen de steden Leiden, Den Haag, Delft, Rotterdam en Gouda met de trekvaarten de Vliet, de Schie, de Gouwe en de Oude Rijn. Tot het jaar 900 was dit gebied grotendeels een veenmoeras. Daarna is het ontwaterd voor de landbouw. Dit leidde tot economische groei en de opkomst van de steden in de dertiende eeuw. Een neveneffect van ontwatering was bodemdaling. Bovendien werd er veel veen afgegraven voor de energievoorziening van de steden. Om het gebied droog te houden, zijn er in de middeleeuwen afwateringskanalen gegraven, zoals de Vliet en de Schie. Deze zijn in de 17e eeuw aangepast om als trekvaart tussen de steden dienst te kunnen doen.
In de toekomst zullen de waterproblemen in het gebied toenemen. Naar verwachting zullen in 2100 extreme regenbuien nog extremer worden en zullen er vaker lange periodes zonder regen zijn. Tegelijkertijd zijn er plannen om veel nieuwe huizen te bouwen. Dit alles kan leiden tot veel meer wateroverlast en grotere droogteproblemen.
In dit project is gekeken of extra tijdelijke waterberging een oplossing kan bieden voor deze problemen. Dat is zo, maar dan is er wel 34 miljoen m3 aan extra berging nodig. Voorgesteld wordt om in de verschillende polders 7,5 miljoen m3 aan nieuwe waterberging aan te leggen, vooral voor de opvang van piekbuien, en daarnaast ten oosten van Zoetermeer een Bentmeer aan te leggen met 26,5 miljoen m3 waterberging als extra bron van zoetwater tijdens droogtes. Uitgaande van twee meter verschil tussen het hoogste en het laagste waterpeil, zal het Bentmeer een oppervlakte moeten krijgen van 13,3 km2. Dit biedt uitgelezen kansen voor recreatie en natuurontwikkeling.
Om het water het Bentmeer in en uit te krijgen, zal een verbinding aangelegd moeten worden met de Rotte in het zuiden en de Oude Rijn in het noorden. Hierdoor zou een oude scheepvaartverbinding tussen de Rotte en de Oude Rijn hersteld worden. Voor de verbinding met de Oude Rijn zijn drie opties bekeken. Voor één van deze opties is een ruimtelijk schetsontwerp gemaakt. In deze optie wordt het Bentmeer verbonden met de Benthuizervaart en wordt de Benthuizervaart via een nieuw te graven vaart verbonden met de huidige Hoogeveense vaart. Deze laatste staat in verbinding met de Oude Rijn (zie de figuren 15 en 16). Langs een deel van denieuwe vaart zullen futuristische “groene” appartementen aangelegd worden met uitzicht over de polder of de vaart. Om de hoogteverschillen voor de scheepvaart niet te groot te maken, kan de Hoogeveense vaart verhoogd aangelegd worden. De appartementsgebouwen langs de vaart kunnen dan ook hoger aangelegd worden, wat ze minder kwetsbaar maakt bij overstromingen.
In alle drie de opties spelen de trekvaarten een essentiële rol voor het transport van water uit en naar het Bentmeer en voor het lozen van overtollig water uit het hele gebied op de Nieuwe Waterweg en de Noordzee. Daarnaast zijn de trekvaarten een goede insteek om de geschiedenis van het landschap te vertellen en te reflecteren op mogelijke toekomsten. Om die reden wordt voorgesteld om langs de nieuwe vaart een jaagpad aan te leggen zodat er met een trekschuit – de “Klimaatschuit” – op gevaren kan worden. Deze kan dienen als varende tentoonstellingsruimte en als locatie voor toekomstdiscussies.
De voorstellen in dit rapport zijn nog niet in detail uitgewerkt en de toekomst is onzeker. Wij kunnen echter niet wachten totdat er zekerheid is. Als we vroeg of laat grootschalige waterberging in Zuid-Holland nodig hebben, moeten we daar nu al over nadenken en snel ruimte reserveren. De kosten zullen hoog zijn, maar de kosten van inactie kunnen nog hoger zijn. Bovendien liggen er ook nieuwe kansen.","Climate change; Water management; heritage; Netherlands; polders; adaptation; tow barge canals","nl","report","Delft University of Technology","","","","","English translation available","","","","","Water Resources","","",""
"uuid:91be8675-5ef9-456e-97a2-f979498e49b0","http://resolver.tudelft.nl/uuid:91be8675-5ef9-456e-97a2-f979498e49b0","Stability of Swept Wing Boundary Layers under Non-Adiabatic Wall Conditions","Barahona Lopez, M. (TU Delft Aerodynamics); van de Weijer, A.F. (TU Delft Aerospace Engineering); Rius Vidales, A.F. (TU Delft Ship Hydromechanics and Structures); Kotsonis, M. (TU Delft Aerodynamics)","","2024","One of the most critical technological challenges embedded in the electrification of future aircraft revolves around the thermal management of batteries and fuel cells. An innovative idea involves using the aircraft’s aerodynamic surfaces to dissipate the extra heat, thereby reducing the impact that traditional thermal management systems (e.g. ram air heat exchanger) have on the overall aerodynamic efficiency of the aircraft. However, the limited experimental research addressing the influence of a heated surface on the stability and transition of the crossflow instability (CFI) hinders the assessment of the aerodynamic impact of this technology for future aircraft, where swept wings are ubiquitous. Thus, the objective of this work is to experimentally study the effect of a heated wall on the stability and final breakdown of CF vortices. To do so, experiments are conducted on a 45◦ swept flat plate wind tunnel model, where the surface temperature is increased by means of a surface-embedded electrical heater, yielding a mean wall-temperature ratio of T_w/T_infty = 1.055. Overall, the experimental (i.e. HWA) and numerical (i.e. CLST) results show that wall heating leads to significant destabilization of the stationary CFI. Interestingly, a spectral analysis of the HWA signal reveals substantial amplification of the traveling CF mode under wall-heating conditions, which in turn appears significantly more destabilized than the stationary CF mode. Additionally, inspection of the high-frequency content in the HWA measurements indicates premature breakdown of the CF vortices and advancement of the laminar-turbulent transition by 6.3% with wall heating. The results presented in this work render a first insight into the impact of a non-adiabatic wall on the development of the crossflow instability and subsequent breakdown to turbulence.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","Aerospace Engineering","","Aerodynamics","","",""
"uuid:a0e7697b-1b8d-4dba-8ed5-5beddd8c8c09","http://resolver.tudelft.nl/uuid:a0e7697b-1b8d-4dba-8ed5-5beddd8c8c09","Aeroelastic Wind Tunnel Testing of Yawed Wind Turbine Rotor with Teetering Hub","Tsatsas, I. (TU Delft Group De Breuker); Georgopoulos, P. (TU Delft Group De Breuker); Sodja, J. (TU Delft Group Sodja); De Breuker, R. (TU Delft Group De Breuker)","","2024","This paper presents an experimental investigation into the aeroelastic behavior of an innovative wind turbine design featuring a downwind two-blade rotor with a teetering hub mounted on a tower with adjustable tilt. The rotor model incorporates two sets of elastic blades—stiff and flexible—for scaling purposes, each instrumented with strain gauges and accelerometers. Ground and wind tunnel tests were conducted to analyze the aeroelastic response. Static deformation tests revealed discrepancies between measured and numerically predicted displacements. Maximum displacements near the tip exceeded numerical predictions by 14% and 31% for flexible and stiff blades respectively. Frequency differences between measured and numerically simulated elastic modes ranged from 0.5% to 18% for both blade sets, as determined by ground vibration tests. No dynamic aeroelastic instability was observed during wind tunnel tests, as rotational speed harmonics dominated the rotor’s response. The tower tilt angle was found to be the dominant parameter in static response, while the tip speed ratio in conjunction with rotational speed emerged as the most crucial parameters in the dynamic response. Overall, this research provides valuable insights into the aeroelastic behavior of yawed, two-blade wind turbine rotors with flexible blades and a teetering hub and could aid in the refinement of numerical models that incorporate elastic blades.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Group De Breuker","","",""
"uuid:2539af15-70fa-4876-9540-316a12771776","http://resolver.tudelft.nl/uuid:2539af15-70fa-4876-9540-316a12771776","Structural integration of a full-composite, double-walled, vacuum-insulated, cryo-compressed tank for the Flying V: a numerical study","Poorte, V.K. (TU Delft Group van Campen); Bergsma, O.K. (TU Delft Group Bergsma); van Campen, J.M.J.F. (TU Delft Group van Campen); Alderliesten, R.C. (TU Delft Group Alderliesten)","","2024","Hydrogen is being investigated as aviation fuel, with the objective to achieve an energy transition for the aviation sector. Effective storage solutions are crucial to mitigate the aerodynamic penalty caused by its low volumetric energy density. The focus of this study is the integration of a cryo-compressed vacuum-insulated storage vessel into the primary structure of aircraft, aiming to enhance structural efficiency. This is achieved by implementing analytical methods to analyse the thermo-mechanical loading of the inner and outer walls of the fuel tank. It is envisioned that the inner wall rather than the outer wall is more suitable to sustain additional loads. However, it is unclear how the cryogenic environment affects the stress state of the composite material. This research contributes to the development of hydrogen-powered aircraft by addressing critical aspects of hydrogen storage, thereby driving the energy transition within the aviation industry.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Group van Campen","","",""
"uuid:c683e122-0bdd-4e13-8a64-591b6cb5a618","http://resolver.tudelft.nl/uuid:c683e122-0bdd-4e13-8a64-591b6cb5a618","Low-fidelity crashworthiness assessment of unconventional aircraft: Modelling of plastic bending","Anand, S. (TU Delft Group Giovani Pereira Castro); Alderliesten, R.C. (TU Delft Group Alderliesten); Castro, Saullo G.P. (TU Delft Group Giovani Pereira Castro)","","2024","Carbon emissions from commercial aircraft are expected to reach more than twice as much as the current levels by 2050. Unconventional aircraft, such as the Flying-V, are projected to achieve more than 20% fuel savings when compared to conventional configurations. However, these unconventional aircraft configurations pose a unique set of design challenges, being one of them the crashworthiness of wing-fuselage structures, which have an oval-shaped cross section that leads to a significant reduction in space underneath the cabin floor. Evaluating the feasibility of a design early in the design phase is vital to avoid cost overruns and minimize the need for drastic design changes. For assessing crashworthiness early in the design phase, the development of low-fidelity models is an attractive as well as a viable option because these models offer both low computational cost and the capability to conduct parametric studies on the crash structure. To develop and implement such low-fidelity models, we propose to explore the analytical modeling of various energy-absorbing mechanisms, namely axial crushing, plastic bending, and joint failure. In the present study, we present the modelling of plastic bending for beam-like structural members. We also present an envisaged method applying user-defined elements to simulate plastic bending in structural members for cases where the location of plastic hinges cannot be predetermined.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-01","","","Group Giovani Pereira Castro","","",""
"uuid:28bd0834-5fbc-4af4-b7fe-bb790c76bebb","http://resolver.tudelft.nl/uuid:28bd0834-5fbc-4af4-b7fe-bb790c76bebb","Transforming Zeolite Tuff and Cigarette Waste into Eco-Friendly Ceramic Bricks for Sustainable Construction","Ibrahim, Jamal Eldin F.M. (University of Miskolc); Basyooni, Mohamed A. (TU Delft Dynamics of Micro and Nano Systems; Selçuk University; National Research Institute of Astronomy and Geophysics); Móricz, Ferenc (University of Miskolc); Kocserha, István (University of Miskolc)","","2024","The use of waste materials has gained attention as a sustainable approach in various industries. Cigarette waste, which is typically discarded as a non-recyclable material, poses a significant environmental challenge due to its toxicity and slow decomposition rate. However, by incorporating this waste into ceramic bricks, new approaches for waste management and resource utilization are explored. This research work provides a detailed evaluation of the possibility of utilizing natural zeolite tuff incorporated with cigarette waste to produce sustainable ceramic bricks. Uniform powders are produced by milling various combinations of zeolitic tuff and cigarette waste using a planetary ball mill. The substitution ratios ranged from 0% to 12% by weight of the zeolitic tuff, with increments of 2%. Ceramic discs were formed by dry pressing and then subjected to sintering at different heat treatment temperatures (950–1250 °C). The impact of the inclusion of cigarette waste on the microstructural and technical features of zeolite tuff-based ceramic bricks has been thoroughly investigated. The results of the experiments demonstrate that incorporating cigarette waste into the development of ceramic bricks leads to improved thermal insulation properties, with thermal conductivity ranging from 0.33 to 0.93 W/m·K. Additionally, these bricks exhibit a lighter weight in a range of 1.45 to 1.96 g/cm3. Although the inclusion of cigarette waste slightly reduces the compressive strength, with values ranging from 6.96 to 58.6 MPa, it still falls within the acceptable range specified by standards. The inclusion of cigarette waste into zeolite tuff is an innovative approach and sustainable practice for reducing energy consumption in buildings while simultaneously addressing the issue of waste disposal and pollution mitigation.","zeolite tuff; cigarette waste; dry compaction; thermal conductivity; compressive strength","en","journal article","","","","","","","","","","","Dynamics of Micro and Nano Systems","","",""
"uuid:ade99ee1-77e8-4c8c-956b-6fe6a666e495","http://resolver.tudelft.nl/uuid:ade99ee1-77e8-4c8c-956b-6fe6a666e495","Flight Testing Reinforcement Learning based Online Adaptive Flight Control Laws on CS-25 Class Aircraft","Konatala, R. (TU Delft Control & Simulation); Milz, Daniel (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Weiser, Christian (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Looye, Gertjan H.N. (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); van Kampen, E. (TU Delft Control & Simulation)","","2024","Unforeseen failures during flight can lead to Loss of Control In-Flight, a significant cause of fatal aircraft accidents worldwide. Current offline synthesized flight control methods have limited capability to recover from failures, due to their limited adaptability. Incremental Approximate Dynamic Programming (iADP) control is a model-agnostic online adaptive control method, which integrates an online identified locally linearized incremental model, with a Reinforcement Learning (RL) based optimization technique to minimize an infinite horizon quadratic cost-to-go. A key challenge for adopting these self-learning flight control methods is validation through flight testing. This paper presents the iADP flight control law design for CS-25 class aircraft to achieve rate control. It outlines the controller evaluation strategy, controller integration, verification & validation procedures, and a discussion on flight test results. To the author’s understanding, this flight test marks the world’s first demonstration of an online RL based automatic flight control system for this aircraft category, demonstrating real-time learning and adaptation capabilities to aircraft configurations.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Control & Simulation","","",""
"uuid:bc389d8e-c007-4f84-abec-1426d4e9ecf4","http://resolver.tudelft.nl/uuid:bc389d8e-c007-4f84-abec-1426d4e9ecf4","Final Design, Manufacturing and Testing of the Clean Sky 2 Distributed Electric Propulsion Scaled Flight Demonstrator D08 DEP-SFD","Döll, Carsten (Office National d'Etudes et de Recherches Aerospatiales); Hoogreef, M.F.M. (TU Delft Flight Performance and Propulsion); Iannelli, Pierluigi (CIRA)","","2024","Within the work package radical new aircraft configuration of Cleansky2 Large Passenger Aircraft, a benefit of more than 20% in fuel consumption and CO2 emission (one of CS2 top level objectives) could be achieved by using various Distributed (hybrid) Electric Propulsion DEP architectures on different more or less radical aircraft configurations. It has therefore been identified as a disruptive technology which shall be de-risked in terms of achievable performance during wind tunnel tests and in terms of handling qualities during flight tests. The electric architecture with typical magnitudes shall also be studied in more detail. As already presented during AIAA SciTech Forum and Exhibition 2023, the D08 Distributed Electric Propulsion DEP version of the D03 Scaled Flight Demonstrator has been designed, manufactured and ground tested from 2020 to May 2023. An incident during the last ground test in May 2023 caused the total loss of this demonstrator. After its analysis, it was decided to robustify the electric architecture by improving the batteries, the wiring, the protections and the monitoring. These changes in the electric architectures lead to structural changes like the shift of the emergency parachute and bigger access hatches. The remanufacturing of the DEP-SFD2 has started in September 2023 for an exhaustive integration test campaign and taxi tests in January and February 2024. At the moment, the qualification flight tests will take place in April 2024 and the mission flight tests in May 2024.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:fc6541b6-b192-4ba2-8932-a3573b44187a","http://resolver.tudelft.nl/uuid:fc6541b6-b192-4ba2-8932-a3573b44187a","Design of a Hydrogen-Powered Crashworthy eVTOL Using Multidisciplinary Analysis and Design Optimization","Keijzer, D.M. (Student TU Delft); Simon Soria, C. (ISAE-SUPAERO); Arends, J.J. (Student TU Delft); Sarıgöl, B. (Student TU Delft); Scarano, F. (TU Delft Aerodynamics); Castro, Saullo G.P. (TU Delft Group Giovani Pereira Castro)","","2024","As of present the Urban Air Mobility market has been dominated by fully electric aircraft. However, hydrogen vehicles have remained relatively undeveloped in this segment, also because hydrogen poses additional design complexities and uncertainties concerning crashworthiness, fuel cell cooling, and low volumetric density. Nevertheless, hydrogen might yield advantages in mission performance owing to its superior gravimetric energy density and greater sustainability when compared to batteries. In this paper, the design procedure of a four-passenger long-range hydrogen eVTOL using Multidisciplinary Analysis and Design Optimization (MADO) is presented. Using MADO, the mission energy of the eVTOL was minimized while abiding by the constraints rooting from the use of hydrogen. Based on this design, the conclusion can be made that the implementation of hydrogen eVTOLs in urban air mobility is feasible whilst taking into account constraints resulting from the use of hydrogen at the preliminary design stage. This led to an aircraft which excels at longer range due to the increased scalability of hydrogen fuel, but having a weight penalty due to auxiliary equipment which hampers its performance and results in a large fuselage and maximum takeoff weight.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Aerodynamics","","",""
"uuid:904aefcb-bdb7-4a15-9f4b-9acc54659486","http://resolver.tudelft.nl/uuid:904aefcb-bdb7-4a15-9f4b-9acc54659486","Autonomous Navigation for Binary Asteroid Landing","Elffers, P.A. (Airbus Defence and Space); Caroselli, Edoardo (AirBus Defence and Space GmbH); van Kampen, E. (TU Delft Control & Simulation); Mooij, E. (TU Delft Astrodynamics & Space Missions)","","2024","This paper investigates the performance of an autonomous navigation system to navigate a spacecraft in the proximity of a binary asteroid system using optical and laser ranging measurements. The knowledge about the binary asteroid is limited to its orbital parameters and ellipsoid shape models. The accelerometer bias random walk is included in the estimation process. Over a four-hour landing maneuver starting from 6770 m altitude and ending at 550 m, the mean position estimation uncertainty is 41.6 m (3$\bm{\sigma}$). It is shown that the navigation accuracy is sensitive to the Sun phase angle, the irregularity of the asteroid shape, and the goodness of fit of the ellipsoid shape model. The paper demonstrates that the navigation system is robust to large errors in the initialization of the extended Kalman filter state. The impact of image distortion and two types of image noise on the navigation performance are investigated.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:d9d3df48-6635-414e-850a-e45904952857","http://resolver.tudelft.nl/uuid:d9d3df48-6635-414e-850a-e45904952857","Aerodynamic Design of a Flying V Aircraft in Transonic Conditions","Laar, Y.A. (TU Delft Aerodynamics); Atherstone, D.M. (TU Delft Group De Breuker); Benad, J. (TU Delft Flight Performance and Propulsion); Vos, Roelof (TU Delft Flight Performance and Propulsion)","","2024","The Flying V is a long-range, flying-wing aircraft where payload and fuel both reside in a V-shaped, crescent wing with large winglets that double as vertical tail planes. The objective of this study is to maximize the lift-to-drag (L/D) ratio of the Flying V in cruise conditions, i.e. CL= 0.26, M = 0.85 and to investigate its off-design performance in high-subsonic conditions. This is done by manually modifying the design parameters that describe the outer mold line of the Flying V and assessing the aerodynamic performance by means of computational fluid dynamics. A 15-million cell, third-order MUSCL, Reynolds-Averaged Navier Stokes solver with the Menter SST turbulence model is used to estimate the aerodynamic coefficients. This numerical model is validated using the experimental data of the ONERA M6 wing. A new, CATIA-based, parametrization of the Flying V is the starting point of the design. Three manual design phases improve the aerodynamic performance while satisfying all constraints. Design modifications include an increase in camber and aft-loading of the wing around 40% of the semispan and improved airfoil sections on the outboard wing generating the required lift coefficient towards an elliptical lift distribution. The twist distribution at the wing-winglet junction is optimized to reduce wave drag. This has resulted in an improvement of L/D from 20.3 from previous studies to 24.2 for the final version, while reducing the cruise angle of attack from 5.2 to 3.6 degrees. The drag divergence Mach number is estimated at 0.925.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Aerodynamics","","",""
"uuid:2ebb06e8-2c85-40e2-8630-1a3d2ce1750d","http://resolver.tudelft.nl/uuid:2ebb06e8-2c85-40e2-8630-1a3d2ce1750d","Towards Universal Parameterization: Using Variational Autoencoders to Parameterize Airfoils","Swannet, K. (TU Delft Flight Performance and Propulsion); Varriale, Carmine (TU Delft Flight Performance and Propulsion); Doan, Nguyen Anh Khoa (TU Delft Aerodynamics)","","2024","A design can only be as good as its mathematical representation. In engineering design optimization, the chosen method of parameterization can have significant impact on the outcomes. This paper introduces a novel methodology for airfoil design parameterization utilizing variational autoencoders (VAEs), a class of neural networks known for their proficiency in reducing dimensionality. However, a significant challenge with VAEs is the interpretability of the encoded latent space. This work aims to address this issue by creating a network with an interpretable latent space, yielding parameters that are understandable to humans. The effectiveness of this approach is evaluated using the comprehensive UIUC airfoil database, which offers a diverse range of airfoil shapes for analysis. We show that a VAE can successfully extract key features of airfoil geometries and parameterize them using six parameters, which show a clear correlation with airfoil properties in a way that remains understandable by the designer. Additionally, it smoothly interpolates the data points, allowing the generation of new airfoils and thus offering a practical and interpretable airfoil parameterization.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:02616c7b-ffaa-45f1-9b32-875a6a9e3061","http://resolver.tudelft.nl/uuid:02616c7b-ffaa-45f1-9b32-875a6a9e3061","Hybrid Soft Actor-Critic and Incremental Dual Heuristic Programming Reinforcement Learning for Fault-Tolerant Flight Control","Teirlinck, C. (Student TU Delft); van Kampen, E. (TU Delft Control & Simulation)","","2024","Recent advancements in fault-tolerant flight control have involved model-free offline and online Reinforcement Learning (RL) algorithms in order to provide robust and adaptive control to autonomous systems. Inspired by recent work on Incremental Dual Heuristic Programming (IDHP) and Soft Actor-Critic (SAC), this research proposes a hybrid SAC-IDHP framework aiming to combine adaptive online learning from IDHP with the high complexity generalization power of SAC in controlling a fully coupled system. The hybrid framework is implemented into the inner loop of a cascaded altitude controller for a high-fidelity, six-degree-of-freedom model of the Cessna Citation II PH-LAB research aircraft. Compared to SAC-only, the SAC-IDHP hybrid demonstrates an improvement in tracking performance of 0.74%, 5.46% and 0.82% in nMAE for nominal case, longitudinal and lateral failure cases respectively. Random online policy initialization is eliminated due to identity initialization of the hybrid policy, resulting in an argument for increased safety. Additionally, robustness to biased sensor noise, initial flight condition and random critic initialization is demonstrated.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Control & Simulation","","",""
"uuid:057a5556-2e58-44c5-acc9-5b78b96a0140","http://resolver.tudelft.nl/uuid:057a5556-2e58-44c5-acc9-5b78b96a0140","Flow analysis of hammerhead launcher geometries in the transonic regime","D'Aguanno, A. (TU Delft Aerodynamics); González Romero, A. (Student TU Delft); Schrijer, F.F.J. (TU Delft Aerodynamics); van Oudheusden, B.W. (TU Delft Aerodynamics)","","2024","Hammerhead launcher configurations, characterized by a larger diameter in the payload fairing than the rest of the launch vehicle, face substantial challenges during transonic operations due to their susceptibility to flow separation and intense pressure fluctuations. This experimental study investigates the influence of the nose and boat-tail geometry on the flow around hammerhead configurations in the transonic regime (Ma=0.7-0.8) and for various angles of attack (α=0-4°). To gain a general understanding of the main flow features, such as shockwave formation, separated flow in the boat tail region, and flow reattachment, oil flow and schlieren visualizations were employed. Schlieren visualizations were also utilized to characterize the level of unsteadiness in these regions. Additionally, particle image velocimetry (PIV) was employed to quantify variations in the velocity field. The study's findings reveal an optimization of flow performance in the presence of a bi-conic nose, attributed to the creation of two-shockwave structures with relatively low intensity. This is in contrast to the ogive and conic noses, which exhibit a single, more detrimental shockwave structure (with the conic nose being the least favorable configuration). The investigation into different boat tail angles indicates that adopting low-angle boat tails (5° and 15° compared to 34°) leads to a noticeable reduction in the separated area, albeit associated with an increase in the range of oscillation of the shockwave structures.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Aerodynamics","","",""
"uuid:2d91a256-f8dd-41dc-9fcb-78c953089730","http://resolver.tudelft.nl/uuid:2d91a256-f8dd-41dc-9fcb-78c953089730","Model-Based Approach for the Simultaneous Design of Airframe Components and their Production Process Using Dynamic MDAO Workflows","Bruggeman, A.M.R.M. (TU Delft Flight Performance and Propulsion); Nikitin, M. (Student TU Delft); la Rocca, G. (TU Delft Flight Performance and Propulsion); Bergsma, O.K. (TU Delft Group Bergsma)","","2024","During the early design stages of airframe components, many possible design architectures and production methods need to be traded to find the best configuration. Evaluating different production methods can be challenging as different production methods put different requirements on the product to be designed. This paper presents a new methodology that enables the inclusion of manufacturing and assembly in the design process. By extending the architectural design space model with components of the production system, the design choices regarding production are made explicit. Through the modeling of product and production requirements and assigning them a verification method, a dynamic MDAO workflow is formulated. Within a dynamic workflow, the design variables, analysis tools, and constraints change depending on the current design vector. The methodology has been applied to the design and manufacturing of a wing rib in which two manufacturing options were traded: metal machining and composite stamp forming. The dynamic MDAO workflow successfully found the Pareto front for both manufacturing methods. The main benefit is that only one workflow needed to be formulated and executed, whereas previously a separate MDAO workflow needed to be created for each combination of product design and production method. Overall, the newly presented methodology enables the optimization and trade-off between different production methods while ensuring the design complies with the production-specific requirements.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:e8f28f08-e648-4a08-814e-f511359020a4","http://resolver.tudelft.nl/uuid:e8f28f08-e648-4a08-814e-f511359020a4","Prediction of Non-Routine Tasks Workload for Aircraft Maintenance with Supervised Learning","Li, H. (Student TU Delft); Ribeiro, M.J. (TU Delft Air Transport & Operations); Santos, Bruno F. (TU Delft Air Transport & Operations); Tseremoglou, I. (TU Delft Air Transport & Operations)","","2024","Aircraft maintenance scheduling is a focus point for airlines. Maintenance is essential to ensure the airworthiness of aircraft, but it comes at the cost of rendering them unavailable for operations. In current operations, aircraft maintenance scheduling must often be updated to include time for non-routine and non-schedule tasks. These non-routine tasks can increase costs, maintenance workload, and uncertainty of the airlines’ operations. This research introduces a supervised learning framework designed to forecast future non-routine task workloads accurately, improving the accuracy of the planned maintenance schedule. This framework consists of two random forest predictors which estimate the amount of non-routine tasks and the number of future work hours that should be allocated in advance for potential non-routine tasks. Our approach produces highly reliable predictions by leveraging a robust dataset obtained from an international airline. The results show an average of 20% improvement versus an existing on-site sampling method. Furthermore, our in-depth analysis of prediction distributions enables the identification of the underlying causes of significant prediction errors, shedding light on the unpredictabilities inherent to non-routine tasks.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Air Transport & Operations","","",""
"uuid:44386502-cdf6-4542-8419-4d31aa4527a1","http://resolver.tudelft.nl/uuid:44386502-cdf6-4542-8419-4d31aa4527a1","Fluid Ablation Interactions on a Compression Ramp at Mach 8","Başkaya, A.O. (TU Delft Aerodynamics); Hickel, S. (TU Delft Aerodynamics); Dungan, Sean (University of Maryland); Brehm, Christoph (University of Maryland)","","2024","Direct numerical simulations (DNS) are performed over 15° compression ramp undergoing ablation at Mach 8 to examine fluid-ablation interactions (FAI) on transitional high-speed boundary layers. The experiments at these conditions with a rigid wall are first numerically replicated for a laminar flow. Heating streaks are introduced by perturbing the flow. The ramp is then replaced by a low-temperature ablator in our DNS. The interaction of the streaks with the recessing ablator surface is then examined. Different approaches from two independently developed solvers are used to explore the problem. Differences in streak amplification and mass blowing magnitudes are observed between the results. We discuss the difficulties in accurately predicting ablation and present the first findings regarding its influence on the perturbation evolution and transition to turbulence for this configuration.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Aerodynamics","","",""
"uuid:fca1d38f-313a-4b87-b33e-99e612888e15","http://resolver.tudelft.nl/uuid:fca1d38f-313a-4b87-b33e-99e612888e15","Exploring the potential of variable stiffness design in reducing the life-cycle impact of composite aircraft parts","van Campen, J.M.J.F. (TU Delft Group van Campen)","","2024","In 2022 Airbus and Boeing combined delivered 1203 commercial aircraft. With an annual predicted growth of 4.3% for the coming 20 years there is an urgent need for end of life solutions that go beyond down-cycling of parts that cannot be reused. Especially carbon fibre reinforced composites are hard to recycle, and attempts to deliver recyclable short fibre reinforced thermoplastic materials see a reduction in specific properties. This is a problem because, the life cycle impact of an aircraft part is predominantly determined by its weight, which drives cumulative CO2-emissions over its lifetime. The transition to renewable energy sources by the aviation sector has the potential to change this relationship drastically. Therefore, it is necessary to begin developing methods to account for life cycle impact already at the start of the mechanical design of an aircraft part. This study proposes to apply variable stiffness laminate design to compensate for relatively lower mechanical performance of a recyclable short fibre reinforced composite laminate. This is successfully demonstrated using the example of a rectangular plate under uniaxial compression with the ATR72 as case study. The results furthermore clearly show that moving from conventional to renewable energy sources, reduces the impact of part-weight on the accumulated CO2-emissions for the life span of the aircraft very significantly, bringing recycling considerations more into focus.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","","Group van Campen","","",""
"uuid:efdab984-5c44-460f-9264-3eccdc2ab6f5","http://resolver.tudelft.nl/uuid:efdab984-5c44-460f-9264-3eccdc2ab6f5","Evolutionary Reinforcement Learning: A Hybrid Approach for Safety-informed Intelligent Fault-tolerant Flight Control","Gavra, V. (Student TU Delft); van Kampen, E. (TU Delft Control & Simulation)","","2024","Recent research in artificial intelligence potentially provides solutions to the challenging problem of fault-tolerant and robust flight control. The current work proposes a novel Safety-informed Evolutionary Reinforcement Learning (SERL) algorithm, which combines Deep Reinforcement Learning (DRL) and neuro-evolution to optimize a population of non-linear control policies. Using SERL, the work has trained agents to provide attitude tracking on a high-fidelity non-linear fixed-wing aircraft model. Compared to a state-of-the-art DRL solution, SERL achieves better tracking performance in nine out of ten cases, remaining robust against faults and changes in flight conditions, while providing smoother actions.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-01","","","Control & Simulation","","",""
"uuid:67714513-f099-4952-bebf-955397696b19","http://resolver.tudelft.nl/uuid:67714513-f099-4952-bebf-955397696b19","A New Perspective on Battery-Electric Aviation, Part II: Conceptual Design of a 90-Seater","de Vries, R. (Elysian Aircraft); Wolleswinkel, Rob E. (Elysian Aircraft); Hoogreef, M.F.M. (TU Delft Flight Performance and Propulsion); Vos, Roelof (TU Delft Flight Performance and Propulsion)","","2024","Battery-electric aviation is commonly believed to be limited to small aircraft and is therefore expected have a negligible impact on the decarbonization of the aviation sector. In this paper we argue that, with the correct choice of design parameters and top-level aircraft requirements, the addressable market is actually substantial. To demonstrate this, the Class-II sizing of a battery-electric 90-seater is performed, and the environmental impact is assessed in terms of well-to-wake CO2-equivalent emissions per passenger-kilometer. The resulting 76-ton aircraft achieves a battery-powered useful range of 800 km for a pack-level energy density of 360 Wh/kg. For this range, it has an energy consumption of 167 Wh per passenger-kilometer and an environmental impact well below that of kerosene, eSAF, or hydrogen-based aircraft alternatives and comparable to land-based modes of transport. These results indicate that, to successfully reduce the climate impact of the aviation sector, battery-electric aircraft should not be designed as a niche product operating from small airfields but as commercial transport aircraft competing with fuel-based regional and narrowbody aircraft.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:df1c0818-7e27-49da-8b53-ce90f0b85806","http://resolver.tudelft.nl/uuid:df1c0818-7e27-49da-8b53-ce90f0b85806","A New Perspective on Battery-Electric Aviation, Part I: Reassessment of Achievable Range","Wolleswinkel, Rob E. (Elysian Aircraft); de Vries, R. (Elysian Aircraft); Hoogreef, M.F.M. (TU Delft Flight Performance and Propulsion); Vos, Roelof (TU Delft Flight Performance and Propulsion)","","2024","Thus far, battery-electric propulsion has not been considered a promising pathway to climate-neutral aviation. Given current and expected battery technology, in most literature battery-electric aircraft are only considered feasible for short ranges (< 400 km) and small payloads (< 19 pax). As a result, battery-electric aircraft development focuses on new aviation segments such as regional and urban air mobility. However, little effort has been made to develop battery-electric aircraft that can replace existing larger aircraft. This paper re-examines the assumptions that lead to the conclusion of limited applicability of battery-electric aircraft. Starting from the range equation, this paper assesses the drivers of two key parameters: the ratio between energy mass and maximum take-off mass, and the maximum lift-to-drag ratio. This assessment, based on Class-I mass and aerodynamic-efficiency estimates, shows that there is a design space where these two parameters can reach significantly higher values than often assumed in the open literature. Based on this finding, several parametric aircraft designs are evaluated, relying on Class-II mass and aerodynamics methods. These parametric studies validate the conclusion from the Class-I assessment. This implies that battery-electric passenger aircraft can play a larger role in climate-neutral aviation than was previously envisioned.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:aa08d0f4-8c42-4049-b50e-899d28f89a3e","http://resolver.tudelft.nl/uuid:aa08d0f4-8c42-4049-b50e-899d28f89a3e","Analysing the Role of the Propulsive System in the Global Civil Aviation Energy Optimisation Framework","Joksimović, Aleksandar (ISAE-SUPAERO); Carbonneau, Xavier (ISAE-SUPAERO); Brazier, F.M. (TU Delft System Engineering); Vingerhoeds, Rob (ISAE-SUPAERO)","","2024","This paper presents a simple explanatory framework to analyse the diverse strategies proposed by the civil aviation sector in attempts to reconcile its growth tendencies with its impact on natural environment. Despite framing the industry as a single entity that has a problem to solve, it is better represented as a diverse set of actors, each responsible for various constituent systems at different phases of their respective life cycles. To elucidate this multi-actor pursuit of higher-level emergent objectives, the paper firstly presents an overview of different development scenarios dedicated to guide the industry towards sustainability. Given that the constituent systems tackled in such strategies strongly depend on each other, the sustainability objective relies on reconciling all the different agendas and contributions in unison, making them collectively compatible with the dynamics of the socio-economic and the natural world. To analyse the problem coherently, a basic description of an arbitrary system as a coarse-grained closed causal network is formulated. A categorisation for the model parameters is proposed to help define the system boundary and interaction with the environment unambiguously, dispensing with the need to know details of the model that represents the system at hand. This formalism was previously derived for preliminary sizing and performance estimation of aeroplane engines; by virtue of recursive nature of the coarse-graining process, the same formalism can be used to describe systems at any arbitrary levels, which enables a small system (in the current paper the system of interest being the propulsive system) to be integrated into a multi-level causal dependence framework. Then, the typical industry evolution scenarios are re-framed on the common ground of the causal network formalism. Subsequently, the framework is extended with a simple quantitative energy-based representation to formulate a qualitative case of how the scenarios could be formulated more coherently to avoid conflicting local optimisation objectives in pursuit of common higher-level goals. Finally, the entirety of the presented elements are brought together in a proposal to conceptualise an industrial system as a life cycle which exchanges matter, energy and information with its large-scale environment. The paper argues that such framing of the problem can pave the way to simplification of the problem of conflicting high-level objectives, by enabling a coherent understanding of the mutual dependence between a system of interest and the much more complex system of systems that is the aeronautical industry.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","System Engineering","","",""
"uuid:638dab1b-30d2-4209-a0ee-1091efd21420","http://resolver.tudelft.nl/uuid:638dab1b-30d2-4209-a0ee-1091efd21420","Half a Tube&Wing: Function-to-Form Mapping Approach to Understanding Fixed-Wing Civil-Aeroplane Design Space","Joksimović, Aleksandar (ISAE-SUPAERO); Brazier, F.M. (TU Delft System Engineering); Carbonneau, Xavier (ISAE-SUPAERO); Vingerhoeds, Rob (ISAE-SUPAERO)","","2024","An overwhelming abundance of innovative civil aeroplane concepts has been presented by the research community in recent decades. Their development has been motivated mainly by need for better operating energy, or in particular the fuel efficiency - the common objective variable for economic and environmental optimisation. This paper focuses on one common conceptual issue with the disruptive concepts which originates in remarkable divergence of the concept space in different directions away from the conventional Tube&Wing paradigm. As a consequence, it becomes increasingly difficult to make a meaningful comparison of any arbitrary pair of concepts by employing the conventional intuitions, definitions, or figures of merit. The objective of the paper is to elaborate a framework that could encompass the entire design space under a common conceptual umbrella. The method we employ relies on systems engineering principles of Function-to-Form mapping. Firstly, a comprehensive review of innovative concepts is provided, with emphasis on the problem of the apparent complexity of the design space arising from the conventional taxonomic intuitions. Then, the descriptive framework is presented, with relevant definitions of function, form and system architecture. First-order application of the framework to the conventional aeroplane design space implies that the Tube&Wing concept family can be represented as roughly one-to-one function-to-form mapping. By analysing the summarised pool of disruptive concepts in the same key, inference is made on existence of an extensive and continuous design space. Furthermore, and argument is presented for existence of the civil-aeroplane performance optimisation trend that aligns with parts of the design space moving away from one-to-one function-to-form mapping. In other words, parts of the design space moving towards the regions in which concepts map as many functions onto as few forms as possible. If extended to the entirety of the life cycle of the system, this framework could reveal even more possibilities for system optimisation, in line with contemporary socio-economic attempts to resolve potentially contradictory requirements and constraints of sustainable growth of the aeronautical industry.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","System Engineering","","",""
"uuid:7ba41bf7-7982-4687-ae97-8c49979e6335","http://resolver.tudelft.nl/uuid:7ba41bf7-7982-4687-ae97-8c49979e6335","Fixed-Wing Aeroplane (Sub)System Design Method: From Abstract to Material Architectures","Joksimović, Aleksandar (ISAE-SUPAERO); Carbonneau, Xavier (ISAE-SUPAERO); Brazier, F.M. (TU Delft System Engineering); Vingerhoeds, Rob (ISAE-SUPAERO)","","2024","This paper presents development of an innovative method for aeroplane system architecture design, based on the principles of causal networks. In light of the environmental crisis that the world faces, it is argued that the new design method should be motivated by sustainability values in the first place. This implies the necessity for a method that is evolvable, as well as for the design artefact to include an awareness of its contribution to dynamics of the higher-level systems within which it is embedded. To that end, the method is based on gradual and iterative development of an initial abstract object which represents relevant system functions over a designated life cycle. The architecture design procedure consists in evolving this abstract object by means of the pre-defined design rules towards a material architectures that satisfies multiple requirements and constraints for multiple actors. The design rules at hand represent a combination of quantitative methods such as first principles of physics and qualitative principles of systems engineering. In complement to system characteristics, rigorous book-keeping of matter and energy interfaces with the object’s surroundings is at the core of the method. To test the developed principles with the elementary method development at hand, a propulsive system architecture case study is elaborated. The case study represents a simple case of a short-medium range engine architecture designed to respond to operating requirements, whose resulting performance is book-kept and evaluated in a much broader context than the operation (in-flight performance), for which engines are commonly preliminary-designed.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","System Engineering","","",""
"uuid:1cd96b09-cf23-43f9-9153-4bda3718343a","http://resolver.tudelft.nl/uuid:1cd96b09-cf23-43f9-9153-4bda3718343a","Preliminary Design and Optimization of a CubeSat Demonstrator for an Origami-inspired Deployable Structure","Velázquez Navarro, Ester (Universidad Rey Juan Carlos); Solano-López, Pablo (Universidad Rey Juan Carlos); Uriol Balbin, I. (TU Delft Group Sinke)","","2024","The demand for pressurized, large structures in space, such as habitats or fuel deposits, is increasing as the space industry grows. The limited payload volume of launch vehicles, combined with their highly constrained shape, presents a significant challenge for these structures. Origami-inspired deployable structures have emerged as a potential solution for this problem. This work aims to design and optimize an origami-inspired deployable structure for use as a technology demonstrator in a 12U CubeSat. The choice of pattern, deployment mechanism, and material considerations are discussed as they are relevant in the initial configuration of the structural prototype. By combining two different types of printable materials, it is possible to create a pattern that is more flexible without the use of mechanical hinges. Then two different modeling methods are analyzed in order to study their physical behavior. Once all the desired configurations are computed, an optimization process is applied in order to obtain the most suitable one under the pre-defined requirements.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Group Sinke","","",""
"uuid:99856753-3c9d-40a1-835b-a62fd1814d80","http://resolver.tudelft.nl/uuid:99856753-3c9d-40a1-835b-a62fd1814d80","Unit Tests for SQL","Spinellis, D. (TU Delft Software Engineering)","","2024","RDBUnit is a unit testing framework designed to test relational database queries, created out of a need for unit testing them while working on software analytics tasks. It is available as a Python package on PyPI and open-source software on GitHub. RDBUnit tests consist of three parts: setup, query, and expected result, with the input and output defined as table contents. The framework utilizes a domain-specific language (DSL) for test specifications, employs a simple parsing mechanism, and uses a class hierarchy for managing database differences. It evaluates test results through SQL code generated and handled by the database engine. RDBUnit supports SQLite, mySQL, and PostgreSQL, and is implemented as a command-line tool suitable for diverse operating systems and continuous integration environments. It has proved beneficial in identifying subtle bugs and facilitating a focused and efficient approach to experimenting with SQL queries, especially in big data scenarios, signifying the assurance provided by unit testing in SQL-centric tasks.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-30","","","Software Engineering","","",""
"uuid:23b99ab5-16c6-452c-887c-25c895a2ce54","http://resolver.tudelft.nl/uuid:23b99ab5-16c6-452c-887c-25c895a2ce54","Calculating S-Parameters and Uncertainties of Coaxial Air-Dielectric Transmission Lines","Ali Mubarak, Faisal (National Metrology Institute VSL); Mascolo, V. (TU Delft Electronics; European Railway Signaling Company); Hussain, Faizan (BCube (Pvt.) Ltd.); Rietveld, Gert (University of Twente)","","2024","Closed-form solutions are presented for calculating the reflection coefficient with corresponding uncertainty of metrology-grade 3.5 mm air-dielectric coaxial transmission lines for use as reference standards in S-parameter measurements up to 33 GHz. The closed-form solutions allow the calculation of the sensitivity coefficients required for calculating the propagation of uncertainties from the material and mechanical parameters of the transmission line toward its reflection coefficient uncertainties. The presented uncertainty framework evaluates every uncertainty source’s contribution, with uncertainties in reflection coefficient ranging from 1 · 10−3 up to 6 · 10−3. The approach is validated up to 33 GHz via a comprehensive measurement comparison of the reflection coefficient parameter for three 3.5 mm transmission lines with 16, 60, and 150 mm lengths. The values obtained by the proposed model agree well within the measurement uncertainties with known traceable calibration results of the transmission lines.","Coaxial transmission line; precision air line; S-parameters; vector network analyzer (VNA); VNA traceability","en","journal article","","","","","","","","2024-06-01","","","Electronics","","",""
"uuid:2a5f61d3-dc5a-4d86-ae1a-79a647d37036","http://resolver.tudelft.nl/uuid:2a5f61d3-dc5a-4d86-ae1a-79a647d37036","Doppler Spectrum Parameter Estimation for Weather Radar Echoes Using a Parametric Semianalytical Model","Dash, T.K. (TU Delft Microwave Sensing, Signals & Systems); Driessen, J.N. (TU Delft Microwave Sensing, Signals & Systems); Krasnov, O.A. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2024","The problem of the limited accuracy of precipitation Doppler spectrum moments estimation measured by fast azimuthally scanning weather radars is addressed. A novel approach for the Doppler moment estimation based on maximum likelihood estimation is proposed. A simplified semianalytical parametric model for the precipitation power spectral density (PSD) as a function of the velocity parameters of the scatterers and the finite radar observation time is derived for typical precipitation-like weather conditions. An inverse problem for estimating the Doppler moments from measurements of the PSD is formulated and solved. It is demonstrated that the variance of the estimation of the Doppler moments approaches the Cramer Rao Lower Bound (CRB) when the observation time approaches infinity. The performance of the proposed approach is compared with some classical techniques and another realization of the maximum likelihood approach based on simulated and experimental data. The results indicate the superiority of the proposed approach, especially for short observation time. Furthermore, a scanning strategy to accurately estimate the Doppler moments based on the true velocity dispersion of the scatterers is provided with the help of the proposed approach.","Doppler velocity retrieval; parametric spectrum estimation; radar signal processing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-30","","","Microwave Sensing, Signals & Systems","","",""
"uuid:01302e26-9428-4c67-acd5-7e5bbe77e7cb","http://resolver.tudelft.nl/uuid:01302e26-9428-4c67-acd5-7e5bbe77e7cb","Remittance dependence, support for taxation and quality of public services in Africa","Konte, Maty (World Bank); Ndubuisi, G.O. (TU Delft Economics of Technology and Innovation; Universiteit Maastricht)","","2024","We explore the heterogeneous effect of migrant remittances on citizens' support for taxation using a sample comprising 45,000 individuals from the Afrobarometer survey round 7 [2016–2018] across 34 African countries. To correct for unobserved heterogeneity, we endogenously identify latent classes/subtypes of individuals that share similar patterns on how their support for taxation is affected by their unobserved and observed characteristics, including remittance dependency. We apply the finite multilevel mixture of regressions approach, a supervised machine learning method to detect hidden classes in the data without imposing a priori assumptions on class membership. Our data are best generated by an econometric model with two classes/subtypes of individuals. In class 1 where more than two-thirds of the citizens belong, we do not find any significant evidence that remittance dependence affects support for taxation. However, in class 2 where the remaining one-third of the citizens belong, we find a significant negative effect of remittance dependence on support for taxation. Furthermore, we find that citizens who have a positive appraisal of the quality of the public service delivery have a lower probability of belonging to the class in which depending on remittance reduces support for taxation. The findings emphasize the need for efficient public services provisioning to counteract the adverse effect of remittances on tax morale.","Africa; public services; remittance; tax morale; taxation","en","journal article","","","","","","","","","","","Economics of Technology and Innovation","","",""
"uuid:0ee04081-ffff-40bb-8773-709e4421a001","http://resolver.tudelft.nl/uuid:0ee04081-ffff-40bb-8773-709e4421a001","Aeroelastic Model for Design of Composite Propellers","Rotundo, C.D. (Student TU Delft); Sinnige, T. (TU Delft Flight Performance and Propulsion); Sodja, J. (TU Delft Group Sodja)","","2024","A tightly coupled aeroelastic design code for composite propeller blades was developed, verified, and used to perform design sensitivity studies. The design code features a structural model that accounts for geometric nonlinearities through the application of a corotational framework, nonlinear responses to loads, and a cross-sectional modelling approach to accurately represent the detailed 3D blade structure as a reduced-order Timoshenko beam element model. Blade element momentum (BEM) theory was used to evaluate aerodynamic loads, which are mapped onto the structural mesh. The nonlinear aeroelastic analysis routine uses Newton's method to converge on a solution, with analytical derivatives for all applied loads. Excellent agreement with other analysis methods was shown during verification studies for all developed models. During validation, performance trends obtained from BEM were consistent with experimental results, with a maximum error of 20% at operating conditions under consideration during this research. The use of either symmetric-unbalanced or symmetric-balanced laminates was considered during sensitivity studies. Small variations in performance in comparison to the rigid propeller were observed from blades constructed out of symmetric-balanced laminates, as the minimal amount of bend-twist and extension-shear coupling resulted in small twist deformations. Conversely, propellers constructed out of symmetric-unbalanced laminates were shown to yield a noticeable variation in thrust and power in comparison to the rigid blade due to the presence of bend-twist and extension-shear coupling, which results in coupling between twist and blade axis deformations. The presence of an aerodynamic wash-out effect was also found to alleviate blade loads, resulting in a lower power requirement at a given thrust setting, and an opposite trend was observed in the presence of a wash-in effect. The proposed analysis framework may be applied towards more comprehensive design studies or optimization in future projects.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Group Sodja","","",""
"uuid:2cee2914-01a6-466b-b461-8fbb642e187d","http://resolver.tudelft.nl/uuid:2cee2914-01a6-466b-b461-8fbb642e187d","Booster Fly-Back Analysis of Reusable Launch Systems","Çavdar, I. (Student TU Delft); Mooij, E. (TU Delft Astrodynamics & Space Missions)","","2024","Within the last decade, the use of launch vehicles has increased as private companies have emerged in the space exploration industry. Compared to the early 1980s, the market for launch vehicles has become significantly more competitive, introducing the desire to have fully reusable launch vehicles. The true benefits of fully reusable launch vehicles can only be achieved once both stages are fully operational and recoverable. This stimulates the need for a comprehensive mission design. In this paper, this is achieved by revisiting the mission profiles of flyback boosters. An extensive analysis of the design-space is performed to identify the contributions of each decision variable to the trajectory design. The results concluded that such an approach supports achieving a more efficient optimization, with better convergence speed and solution performance.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:23b26a9e-7613-453e-a2ef-6700a6562f42","http://resolver.tudelft.nl/uuid:23b26a9e-7613-453e-a2ef-6700a6562f42","Swept Transition Experimental Platform (STEP)","Rius Vidales, A.F. (TU Delft Ship Hydromechanics and Structures); Barahona Lopez, M. (TU Delft Aerodynamics); Kotsonis, M. (TU Delft Aerodynamics)","","2024","A new experimental facility named Swept Transition Experimental Platform (STEP) has been designed and built for detailed studies of crossflow instability and its interaction with surface irregularities and varying wall temperature conditions. The STEP is designed for use in the anechoic low-turbulence wind tunnel facility at the Delft University of Technology (TU Delft). The new facility consists of a swept flat-plate model with a movable leading edge capable of precisely translating to create forward/backward-facing step irregularities. In addition, the plate’s wall temperature can be adjusted to study the potential of thermal laminar flow control. An adjustable pressure body provides the favorable pressure distribution required to enhance the development of crossflow instability. Static pressure measurements are conducted to characterize the nominal pressure distribution. In addition, detailed hot-wire measurements and theoretical stability calculations reveal that the combination of discrete roughness elements, pressure distribution, and experimental facility allows for a detailed study of the development of crossflow instability in the linear and non-linear growth regime. Consequently, the STEP enables further fundamental research on laminar flow control at TU Delft.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Aerodynamics","","",""
"uuid:fae759b3-20d7-4208-92de-d8bf2dd5b9a6","http://resolver.tudelft.nl/uuid:fae759b3-20d7-4208-92de-d8bf2dd5b9a6","Integrated Shape and Trajectory Optimisation of Hypersonic Waveriders","Agante de Carvalho, J.R. (Student TU Delft); Mooij, E. (TU Delft Astrodynamics & Space Missions)","","2024","This research performs a surrogate-assisted shape optimisation of hypersonic waveriders, where the trajectories of each shape are optimised with a multi-objective evolutionary algorithm for heat-load and cross-range. A study on the best evolutionary algorithm, node control strategy for angle of attack and bank angle profiles, and population size to use in the trajectory optimisation phase, are identified. The aerodynamics of the waveriders is computed with a new local surface inclination method blending the modified Newtonian and tangent wedge solutions, while the convective heat flux is computed for the leading edges using the Newton-Kays engineering model. Shape variability is introduced according to the layout of central composite designs, and analysis of variance is applied to identify the shape features driving the two objectives. Shock angle, leading edge radius and overall vehicle dimensions are the strongest drivers, while details on the planform shape are less relevant and should be left for posterior studies. The surrogates are a good approximation of the true fitness functions, so they were optimised in a single-objective framework, producing two optimal waverider designs.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:fd8d4db5-b955-4547-a9e7-dec0b3d16b50","http://resolver.tudelft.nl/uuid:fd8d4db5-b955-4547-a9e7-dec0b3d16b50","Gravity-Field Estimation of Asteroids","Mooij, E. (TU Delft Astrodynamics & Space Missions); Root, B.C. (TU Delft Planetary Exploration)","","2024","With the increasing interest in the Solar System's smaller bodies, quite a few missions have been sent to comets and asteroids, and more will be send in the near future. Due to the large distances involved, communication to command mission parameters takes a long time, which has a negative impact on operational safety. Autonomous navigation would be one of the key technologies that can make the mission more robust, safe, and cost e ective. This is especially true if one considers the unknown ight environment when the spacecraft is rst encountering the body. Most asteroids and comets have a very irregular shape and unknown mass distribution. Therefore, knowledge about its irregular gravity eld will be directly bene cial as input to orbital corrections and manoeuvre planning. This paper addresses the estimation process of gravity- eld parameters that could potentially be implemented in an autonomous navigation system. The focus is on a spherical-harmonic modelling of asteroid Eros-433, most notably outside the Brillouin sphere where the validity of the model is guaranteed. By using Kalman ltering it is shown that all degree and order coe cients up to degree 8 can be estimated with an error below 10%. This is the rst step towards an autonomous navigation system that can operate in a highly-perturbed environment close to the asteroid.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:0511e887-0575-4d17-9b71-3254f20378c0","http://resolver.tudelft.nl/uuid:0511e887-0575-4d17-9b71-3254f20378c0","Aeroelastic Tailoring of a Strut-Braced Wing for a Medium Range Aircraft","Carrillo Córcoles, X. (TU Delft Group Sodja); De Breuker, R. (TU Delft Group De Breuker); Sodja, J. (TU Delft Group Sodja)","","2024","This study explores the implementation of aeroelastic tailoring in the design of a regional aircraft featuring a strut-braced wing (SBW). Making use of the aeroelastic optimisation framework from Delft University of Technology, PROTEUS, the research addresses two distinct cases. The first case involves a simplified SBW geometry to validate the modifications of PROTEUS, which were conducted to include the strut in the aeroelastic analysis. Static and dynamic load cases are compared with a NX Nastran aeroelastic model, showing good agreement in displacements, strains, and gust response. In the second case, the study investigates the weight-saving potential of aeroelastic tailoring in an SBW aircraft based on the ATR-72. Three optimisation scenarios, allowing various laminate types, are examined: unbalanced symmetric laminates, balanced symmetric laminates, and a thickness optimisation with a prescribed balanced symmetric stacking sequence. The results reveal that the prescribed stacking sequence limits stiffness tailoring, thereby also reducing potential weight savings. Moreover, the study shows how the presence of a strut reduces wing deflections, limiting the effectiveness of aeroelastic tailoring.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Group Sodja","","",""
"uuid:014ffc1c-0adb-4f91-91b7-65a86e3e73eb","http://resolver.tudelft.nl/uuid:014ffc1c-0adb-4f91-91b7-65a86e3e73eb","High-Dimensional Bayesian Optimisation with Large-Scale Constraints - An Application to Aeroelastic Tailoring","Maathuis, H.F. (TU Delft Group Giovani Pereira Castro); De Breuker, R. (TU Delft Group De Breuker); Castro, Saullo G.P. (TU Delft Group Giovani Pereira Castro)","","2024","Design optimisation potentially leads to lightweight aircraft structures with lower environmental impact. Due to the high number of design variables and constraints, these problems are ordinarily solved using gradient-based optimisation methods, leading to a local solution in the design space while the global space is neglected. Bayesian Optimisation is a promising path towards sample-efficient, global optimisation based on probabilistic surrogate models. While for problems with a low number of design variables, Bayesian Optimisation methods have demonstrated their strength, the scalability to high-dimensional problems while incorporating large-scale constraints is still lacking. Especially in aeroelastic tailoring where directional stiffness properties are embodied into the structural design of aircraft, to control aeroelastic deformations and to increase the aerodynamic and structural performance, the safe operation of the system needs to be ensured by involving constraints resulting from different analysis disciplines. Hence, a global design space search becomes even more challenging. The present study attempts to tackle the problem by using high-dimensional Bayesian Optimisation in combination with a dimensionality reduction approach to solve the optimisation problem occurring in aeroelastic tailoring, presenting a novel approach for high-dimensional problems with large-scale constraints. Experiments on well-known benchmark cases with black-box constraints show that the proposed approach can incorporate large-scale constraints.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Group Giovani Pereira Castro","","",""
"uuid:4044dca9-7a65-444b-b733-31c8d11a4d8e","http://resolver.tudelft.nl/uuid:4044dca9-7a65-444b-b733-31c8d11a4d8e","Optimal Control for Distributed Aeroelastic Morphing Structure with Uncertainties and Imperfections","Mkhoyan, T. (TU Delft Arts & Crafts); Wang, Xuerui (TU Delft Group Wang); De Breuker, R. (TU Delft Group De Breuker)","","2024","This research takes a further step towards the development of an autonomous aeroservoelastic wing concept with distributed flaps. The wing demonstrator, developed within the TU Delft SmartX project, aims to demonstrate in-flight performance optimization and multi-objective control using an over-actuated wing design. To address the challenges posed by the aeroelastic system's nonlinearities and uncertainties, this paper employs an optimal control method relying on solving the State-Dependent Riccati Equation (SDRE). Geometrical nonlinearities, introduced in the form of plunge and torsion stiffness, make the system state-dependent and unsuitable for linear control methods. Additionally, a backlash model is incorporated to represent the uncertainty of the actuation system. The control strategy is implemented in a multi-objective manner to perform maneuver and gust load alleviation while accounting for the nonlinearities and uncertainties using the SDRE control. Firstly, a numerical sample case is investigated involving a state-dependent and highly non-linear canard aircraft configuration, to assess the ability of the SDRE control method. Then, in a numerical experiment, the effectiveness of the control strategy is evaluated through the nonlinear aeroelastic model. Evaluations are made on the practicality of the control approach, laying a foundation for future static and dynamic wind tunnel experiments with the SmartX-Neo","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Arts & Crafts","","",""
"uuid:63809bbd-a531-4b34-88f9-a2844d257982","http://resolver.tudelft.nl/uuid:63809bbd-a531-4b34-88f9-a2844d257982","Incremental Nonlinear Dynamic Inversion control with Flight Envelope Protection for the Flying-V","Stougie, P.J. (Student TU Delft); Pollack, T.S.C. (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation)","","2024","To reduce the impact of aviation on the environment, technological innovations, such as the Flying-V are required. The Flying-V is a proposed commercial flying wing, which uses the Airbus A350-900 as reference aircraft. In this work, a Flight Control system for the Flying-V is proposed with a longitudinal ��∗ control law, and a Rate Control Attitude Hold roll control law. This Flight Control System also includes a Flight Envelope Protection law to prevent reaching angles of attack higher than 30 degrees, where the Flying-V becomes statically unstable. The FEP also prevents the Flying-V from reaching load factors above 2.5 and limits the roll angle. The control laws are tuned to be within level 1 handling qualities in the selected approach and cruise conditions, with the presence of sensor dynamics, and a digital control system. Robustness for aerodynamic uncertainties is also shown. Finally, it is shown that the FEP is able to prevent the angle of attack from becoming too large.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Control & Simulation","","",""
"uuid:f07cb2c5-328b-4c82-9724-2126affc7f87","http://resolver.tudelft.nl/uuid:f07cb2c5-328b-4c82-9724-2126affc7f87","Certification of Reinforcement Learning Applications for Air Transport Operations Based on Criticality and Autonomy","Ribeiro, M.J. (TU Delft Air Transport & Operations); Tseremoglou, I. (TU Delft Air Transport & Operations); Santos, Bruno F. (TU Delft Air Transport & Operations)","","2024","Despite its success in various research domains, Reinforcement Learning (RL) faces challenges in its application to air transport operations due to the rigorous certification standards of the aviation industry. The existing regulatory framework fails to provide adequate, acceptable means of compliance for RL applications, and thus, there is no legal framework for their safe deployment yet. Guidelines must be formulated to certify RL models aimed at air transport operations to enable real-world utilisation of these promising methods. These guidelines must consider the unique characteristics of these models, deviating from the methodology of current guidelines crafted before the emergence of ML applications. The paper proposes novel certification requirements for RL models based on their technical characteristics, safety-criticality, and autonomy. This framework covers the choice of the RL algorithm and analyses the actions, agents, environment, and potential hazards and risks of the RL application. Additionally, this work outlines the evidence the certification applicant must present to demonstrate compliance with these requirements. While this framework is not a complete solution for the complex problem of certifying RL, it is intended to serve as an initial framework which can be extended in cooperation with regulatory entities.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Air Transport & Operations","","",""
"uuid:c63faa48-2ab5-4123-b1e3-bc7eb866b112","http://resolver.tudelft.nl/uuid:c63faa48-2ab5-4123-b1e3-bc7eb866b112","Optimization of Tollmien-Schlichting waves control: comparison between a deep reinforcement learning and particle swarm optimization approach","Mohammadikalakoo, B. (TU Delft Aerodynamics); Kotsonis, M. (TU Delft Aerodynamics); Doan, Nguyen Anh Khoa (TU Delft Aerodynamics)","","2024","This work focuses on the suppression of Tollmien-Schlichting (TS) waves in a two-dimensional laminar boundary layer using optimized unsteady suction and blowing jets as an Active Flow Control (AFC) method. The suppression of TS waves via this AFC system is enabled through two artificial intelligence-based optimization methodologies: Single-Step Deep Reinforcement Learning (SDRL) and Particle Swarm Optimization (PSO). The primary aim of this research is to assess the performance of these methods in optimizing the AFC parameters with respect to convergence rate, computational efficiency, and ability to find an optimum control state. The findings demonstrate the success of both methods in finding appropriate control parameters resulting in TS wave attenuation by up to 40 dB in the maximum convective instability amplitude for the linear and nonlinear stages of development. The comparative study in this paper presents the effectiveness of the SDRL algorithm in optimizing the AFC system for TS waves’ suppression and demonstrates that it can outperform PSO in terms of convergence rate and computational efficiency alongside a better performance in finding an improved optimum for linear control cases. However, the advantage of the SDRL-based controller over the PSO-based one diminishes in multi-frequency nonlinear control cases where the controller is located downstream and attempting to control highly amplified multi-modal TS waves.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Aerodynamics","","",""
"uuid:ed93cf78-331e-4939-b51e-ffcca6de7160","http://resolver.tudelft.nl/uuid:ed93cf78-331e-4939-b51e-ffcca6de7160","Parametric study of a switchable vortex generator for load alleviation in transonic conditions","Marino, Luca (TU Delft Group Sodja); Kiat, I. (Student TU Delft); Eberle, Adrian (Airbus Operations GmbH); Sodja, J. (TU Delft Group Sodja)","","2024","This paper investigates the impact of introducing a switchable vortex generator (SVG), acting as a mini-tab, on the aerodynamic performance of a high-aspect-ratio wing's outer section in transonic regime. A parametric study is conducted employing computational fluid dynamics 2D simulations, focusing on the aerodynamic effects of changing the chord-wise position and height of the vane of a SVG located on the airfoil upper surface in both nominal cruise conditions and for varying angles of attack. The analysis reveals that mini-tabs can strongly affect the aerodynamic forces produced by the wing section, showing great potential for load alleviation and control, but also emphasising the need for a careful parameter selection to reduce undesirable effects such as the generation of shock waves. In cruise conditions, lift reduction increases with the vane height and has its maximum for chord-wise positions at 60% of the chord-length. However, SVGs located in the first half of the chord-length yield more robust performance for varying angle of attack, without sharp lift variations or generated shock waves, and a delayed stall onset. High SVGs (≥3% chord-length) can also lead to strong shock waves on the airfoil lower surface at small or negative angle of attack, while small SVGs (","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Group Sodja","","",""
"uuid:68093421-4edf-4678-89e7-851520bdcbae","http://resolver.tudelft.nl/uuid:68093421-4edf-4678-89e7-851520bdcbae","Bi-sinusoidal light stimulation reveals an enhanced response power and reduced phase coherence at the visual cortex in migraine","van den Hoek, Thomas C. (Leiden University Medical Center); Perenboom, Matthijs J.L. (Leiden University Medical Center); Terwindt, Gisela M. (Leiden University Medical Center); Tolner, Else A. (Leiden University Medical Center); van de Ruit, M.L. (TU Delft Biomechatronics & Human-Machine Control; Leiden University Medical Center)","","2024","Introduction: Migraine is associated with enhanced visual sensitivity during and outside attacks. Processing of visual information is a highly non-linear process involving complex interactions across (sub)cortical networks. In this exploratory study, we combined electroencephalography with bi-sinusoidal light stimulation to assess non-linear features of visual processing in participants with migraine.
Methods: Twenty participants with migraine (10 with aura, 10 without aura) and ten non-headache controls were measured (outside attacks). Participants received bi-sinusoidal 13 + 23 Hz red light visual stimulation. Electroencephalography spectral power and multi-spectral phase coherence were compared between groups at the driving stimulation frequencies together with multiples and combinations of these frequencies (harmonic and intermodulation frequencies) caused by non-linearities.
Results: Only at the driving frequency of 13 Hz higher spectral power was found in migraine with aura participants compared with those with migraine without aura and controls. Differences in phase coherence were present for 2nd, 4th, and 5th-order non-linearities in those with migraine (migraine with and without aura) compared with controls. Bi-sinusoidal light stimulation revealed evident non-linearities in the brain’s electroencephalography response up to the 5th order with reduced phase coherence for higher order interactions in interictal participants with migraine.
Discussion: Insight into interictal non-linear visual processing may help understand brain dynamics underlying migraine attack susceptibility. Future research is needed to determine the clinical value of the results.","visual system; bi-sinusoidal; non-linear; EEG; steady-state response","en","journal article","","","","","","","","","","","Biomechatronics & Human-Machine Control","","",""
"uuid:686af1c3-dd00-4eff-9fbb-95b63c4ec268","http://resolver.tudelft.nl/uuid:686af1c3-dd00-4eff-9fbb-95b63c4ec268","An algae-derived partially renewable epoxy resin formulation for glass fibre-reinforced sustainable polymer composites","Apostolidis, Dimitrios; Dyer, W.E. (TU Delft Group Kumru); Dransfeld, C.A. (TU Delft Group Dransfeld); Kumru, B. (TU Delft Group Kumru)","","2024","Utilization of sustainable feedstocks to fabricate renewable thermosetting epoxy resins has been of great interest recently; however, their translation into composite structures and benchmark comparisons are poorly understood. Phloroglucinol is a phenolic molecule obtained from brown algae, and its epoxidized form is a high viscosity, high reactivity monomer. In this study, the potential of epoxidized phloroglucinol as a laminating resin was examined in comparison with a bisphenol A diglycidyl ether (BADGE) epoxy monomer employing the Epikure 04908 linear amine hardener system. Utilization of a reactive diluent for PHTE resin was necessary for room temperature laminating applications to reduce viscosity, and the thermomechanical properties of PHTE-based resins and composites are superior to those of BADGE systems.","","en","journal article","","","","","","","","","","","Group Kumru","","",""
"uuid:33866541-85c5-4391-9f71-73272918d178","http://resolver.tudelft.nl/uuid:33866541-85c5-4391-9f71-73272918d178","Reducing without losing: Reduced consumption and its implications for well-being","Vollebregt, Madeleine (Universiteit van Amsterdam); Mugge, R. (TU Delft Marketing and Consumer Research; Universiteit van Amsterdam); Thürridl, Carina (Universiteit van Amsterdam); van Dolen, Willemijn (Universiteit van Amsterdam)","","2024","Consumption is often considered important for achieving and maintaining well-being, particularly in current market societies. However, overconsumption is a significant driver of climate issues as it results in material scarcity and carbon emissions. Reduced consumption is one possible solution to environmental problems associated with climate change, as it lowers resource use and prevents waste creation. However, reductions in consumption may be perceived as a threat to human well-being. In this paper, we systematically review the literature to provide an overview of empirical studies that investigate the relationship between reduced consumption and well-being at the individual level. The majority of selected studies suggest that reduced consumption is associated with higher levels of well-being or that there is not a significant relationship. Others indicate potential negative effects. The results suggest that reducing consumption does not typically have a negative association with the well-being of consumers in wealthy nations. Reported increases in well-being may be due to supporting consumers' autonomy, environmental mastery, and social relationships. Societal norms and the consumption behavior of our peers likely influence the relationship. By conducting the first systematic literature review on the relationship between reduced consumption and well-being, we provide a more integrated understanding of consumption's role in well-being and in what contexts reduced consumption can be beneficial. Reduced consumption seems achievable from a well-being perspective, but more research is needed regarding practical implications for marketers, government, and consumers.","Well-being; Happiness; Reduced consumption; Absolute reductions; Systematic literature review","en","review","","","","","","","","","","","Marketing and Consumer Research","","",""
"uuid:a9cf4a5f-082f-4ad0-9f33-46e333971773","http://resolver.tudelft.nl/uuid:a9cf4a5f-082f-4ad0-9f33-46e333971773","WInDI: a Warp-Induced Dust Instability in protoplanetary discs","Aly, H.A. (TU Delft Astrodynamics & Space Missions; University Heidelberg); Nealon, Rebecca (University of Warwick); Gonzalez, Jean-François (Université Claude Bernard Lyon 1)","","2024","We identify a new dust instability that occurs in warped discs. The instability is caused by the oscillatory gas motions induced by the warp in the bending wave regime. We first demonstrate the instability using a local 1D (vertical) toy model based on the warped shearing box coordinates and investigate the effects of the warp magnitude and dust Stokes number on the growth of the instability. We then run 3D smoothed particle hydrodynamics (SPH) simulations and show that the instability is manifested globally by producing unique dust structures that do not correspond to gas pressure maxima. The 1D and SPH analysis suggest that the instability grows on dynamical time-scales and hence is potentially significant for planet formation.","Planet formation; Fluid instabilities; Dust evolution; Warped discs; protoplanetary disks","en","journal article","","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:9c9e7446-41fa-4ba4-84c3-03575873e5b0","http://resolver.tudelft.nl/uuid:9c9e7446-41fa-4ba4-84c3-03575873e5b0","Learning-Based Multi-UAV Flocking Control With Limited Visual Field and Instinctive Repulsion","Bai, Chengchao (Harbin Institute of Technology); Yan, Peng (Harbin Institute of Technology); Piao, Haiyin (Northwestern Polytechnical University; SADRI Institute); Pan, W. (TU Delft Robot Dynamics; The University of Manchester); Guo, Jifeng (Harbin Institute of Technology)","","2024","This article explores deep reinforcement learning (DRL) for the flocking control of unmanned aerial vehicle (UAV) swarms. The flocking control policy is trained using a centralized-learning-decentralized-execution (CTDE) paradigm, where a centralized critic network augmented with additional information about the entire UAV swarm is utilized to improve learning efficiency. Instead of learning inter-UAV collision avoidance capabilities, a repulsion function is encoded as an inner-UAV 'instinct.' In addition, the UAVs can obtain the states of other UAVs through onboard sensors in communication-denied environments, and the impact of varying visual fields on flocking control is analyzed. Through extensive simulations, it is shown that the proposed policy with the repulsion function and limited visual field has a success rate of 93.8% in training environments, 85.6% in environments with a high number of UAVs, 91.2% in environments with a high number of obstacles, and 82.2% in environments with dynamic obstacles. Furthermore, the results indicate that the proposed learning-based methods are more suitable than traditional methods in cluttered environments.","Autonomous aerial vehicles; Collision avoidance; Deep reinforcement learning (DRL); flocking control; inter-unmanned aerial vehicle (UAV) collision avoidance; limited visual field; Optimization; Reinforcement learning; Sensors; Training; UAVs; Visualization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-08","","","Robot Dynamics","","",""
"uuid:59b4d50b-6e74-48ca-8d84-fef1128b0ac2","http://resolver.tudelft.nl/uuid:59b4d50b-6e74-48ca-8d84-fef1128b0ac2","Near-Optimal Feedback Guidance for Low-Thrust Earth Orbit Transfers","Atmaca, D. (TU Delft Control & Simulation); Pontani, Mauro (Sapienza University of Rome)","","2024","This research describes a near-optimal feedback guidance, based on nonlinear orbit control, for low-thrust Earth orbit transfers. Lyapunov stability theory leads to proving that although several equilibria exist, only the desired operational conditions are associated with a stable equilibrium. This ensures quasi-global asymptotic convergence toward the desired final orbit. The dynamical model includes the effect of eclipsing on the available thrust, as well as all the relevant orbit perturbations, such as several harmonics of the geopotential, solar radiation pressure, aerodynamic drag, and gravitational attraction due to the Sun and the Moon. Near-optimality of the feedback guidance comes from careful selection of the control gains. They are identified in two steps. Step (a) is an extensive table search in which the gains are changed in a large interval. Step (b) uses a numerical optimization algorithm that refines the gains found in (a), while minimizing the time of flight. For the numerical simulations, two scenarios are defined: (i) nominal conditions and (ii) nonnominal conditions, which arise from orbit injection errors and stochastic failures of the propulsion system. For case (i), gain optimization leads to obtaining numerical results very close to those corresponding to a known optimal orbit transfer with eclipse arcs. Moreover, for case (ii), extensive Monte Carlo simulations demonstrate that the nonlinear feedback guidance at hand is effective in driving a spacecraft from a low Earth orbit to a geostationary orbit, also in the presence of nonnominal flight conditions.","Earth Orbit Transfers; Low-thrust Space Propulsion; Feedback Guidance and Control","en","journal article","","","","","","","","","","","Control & Simulation","","",""
"uuid:7c311707-8898-492d-b580-1e298cd09e32","http://resolver.tudelft.nl/uuid:7c311707-8898-492d-b580-1e298cd09e32","Luck, Epigenetics and the Worth of Collective Agents","Chiapperino, Luca (University of Lausanne); Sand, M. (TU Delft Ethics & Philosophy of Technology)","","2024","","Collective Responsibility; Responsibility; Luck; Epigenetics; Blame","en","book chapter","Bristol University Press","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:e3e91723-a52e-4217-b581-cadc96de5992","http://resolver.tudelft.nl/uuid:e3e91723-a52e-4217-b581-cadc96de5992","Drying of silty soil treated with superabsorbent hydrogels: Retention behaviour and cracking","Liaudat, J. (TU Delft Geo-engineering); Muraro, S. (TU Delft Geo-engineering)","","2024","Desiccation cracks in soils pose risks to the serviceability and safety of geotechnical infrastructure worldwide. This paper aims to investigate the potential of superabsorbent hydrogels (SAH) as innovative soil amendment to mitigate soil drying effects and cracking. Laboratory tests were conducted on an initially saturated silty soil treated with different types and dosages of SAH. Desiccation cracking tests, shrinkage tests, and water retention tests were performed to analyse the cracking process, evaporation rate, and retention properties. The tests were integrated with micro-CT scan analyses to observe changes in soil fabric due to the SAH addition. The results indicate that SAH particles serve as internal water reservoirs, extending the normal shrinkage stage and maintaining higher suctions without significant desaturation, in comparison to untreated soil. The addition of SAH reduces the evaporation rate, particularly at a dosage of 0.1%. The progression of cracking occurs at suctions below the air entry value, and the inclusion of SAH reduces the rate of crack development. These findings highlight the need for additional research on SAH as a promising soil treatment for geotechnical applications.","Soil; Desiccation cracking; Superabsorbent hydrogels","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:46f7dd57-fc54-415c-8793-a6696014963f","http://resolver.tudelft.nl/uuid:46f7dd57-fc54-415c-8793-a6696014963f","Full-length single-molecule protein fingerprinting","Filius, M. (TU Delft BN/Chirlmin Joo Lab; Kavli institute of nanoscience Delft); van Wee, R.G. (TU Delft BN/Chirlmin Joo Lab; Kavli institute of nanoscience Delft); de Lannoy, C.V. (TU Delft BN/Chirlmin Joo Lab; Wageningen University & Research; Kavli institute of nanoscience Delft); Westerlaken, I. (TU Delft BT/Industriele Microbiologie; Kavli institute of nanoscience Delft); Li, Zeshi (Kavli institute of nanoscience Delft); Kim, S.H. (TU Delft BN/Chirlmin Joo Lab; Ewha Womans University; Kavli institute of nanoscience Delft); de Agrela Pinto, C. (TU Delft BN/Arjen Jakobi Lab; Kavli institute of nanoscience Delft); Wu, Yunfei (Universiteit Utrecht); Boons, Geert-Jan (Universiteit Utrecht); Pabst, Martin (TU Delft BT/Environmental Biotechnology); de Ridder, Dick (Wageningen University & Research); Joo, C. (TU Delft BN/Chirlmin Joo Lab; Kavli institute of nanoscience Delft)","","2024","Proteins are the primary functional actors of the cell. While proteoform diversity is known to be highly biologically relevant, current protein analysis methods are of limited use for distinguishing proteoforms. Mass spectrometric methods, in particular, often provide only ambiguous information on post-translational modification sites, and sequences of co-existing modifications may not be resolved. Here we demonstrate fluorescence resonance energy transfer (FRET)-based single-molecule protein fingerprinting to map the location of individual amino acids and post-translational modifications within single full-length protein molecules. Our data show that both intrinsically disordered proteins and folded globular proteins can be fingerprinted with a subnanometer resolution, achieved by probing the amino acids one by one using single-molecule FRET via DNA exchange. This capability was demonstrated through the analysis of alpha-synuclein, an intrinsically disordered protein, by accurately quantifying isoforms in mixtures using a machine learning classifier, and by determining the locations of two O-GlcNAc moieties. Furthermore, we demonstrate fingerprinting of the globular proteins Bcl-2-like protein 1, procalcitonin and S100A9. We anticipate that our ability to perform proteoform identification with the ultimate sensitivity may unlock exciting new venues in proteomics research and biomarker-based diagnosis","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-13","","","BN/Chirlmin Joo Lab","","",""
"uuid:3ede2611-c689-43b2-87ce-ddea17e64367","http://resolver.tudelft.nl/uuid:3ede2611-c689-43b2-87ce-ddea17e64367","Dams are fragile: The frenzy and legacy of modern infrastructures along the Klamath and Allegheny Rivers","Iuorio, Luca (TU Delft Environmental Technology and Design)","","2024","This article discusses the socio-technical process of dam construction in the United States from the early 20th century to the present. It examines how marginal places have been the object of industrial modifications through the inventiveness and entrepreneurship of social groups and local individuals who, supported by federal measures, have built power and cultural relations on territorial scales for decades. Historical reconstructions describe the generative processes of places through dam construction to demonstrate that the contemporary built environment is a product of natural and human-made relationships. Events associated with modern dam constructions and, more recently, with demolitions along the Klamath and Allegheny Rivers are critically discussed to illustrate how environmental resources relate to and interact with technology, human practices, and places. The article suggests that dams have been engines for industrial growth and technological devices to reframe the interdependencies between people and the environment. Dams supply people with water and energy and protect them and their property from droughts, floods, and fires. However, after a century of operations, these structures are reaching the ends of their lifecycles. In light of dam removal trends in the United States, the article presents a historical narrative on the societal legacy of dams. The intent is to share a broad understanding of the current technical and political debates on whether to demolish or maintain US dams in the future.","Modernity; Dams; Technology; Removal","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-11","","","Environmental Technology and Design","","",""
"uuid:d631ea6e-254a-4b40-906e-1687c076a1d9","http://resolver.tudelft.nl/uuid:d631ea6e-254a-4b40-906e-1687c076a1d9","Multifaceted Functionalities of Bridge-Type DC Reactor Fault Current Limiters: An Experimentally Validated Investigation","Behdani, B. (TU Delft Intelligent Electrical Power Grids); Moghim, Ali (Islamic Azad University); Mousavi, Sheyda (Zanjan University); Soltanfar, Mostafa (University of Kashan); Hojabri, Mojgan (Lucerne University of Applied Sciences and Arts)","","2024","With the ongoing expansion and interconnection of electrical power systems, alongside the rapid proliferation of renewable distributed generations (DGs), the short-circuit extent in the power grid is experiencing a significant rise. Fault current limiters (FCLs) have been introduced in an effort to address this issue, ensuring the robustness and sustainability of expensive power system components when confronted with short-circuit faults. Among the various types of FCLs, bridge-type DC reactor fault current limiters (BDCR-FCLs) have emerged as one of the most promising options. While BDCR-FCLs have shown excellent properties in limiting harmful short-circuit currents, they are also advantageous in other respects. This paper investigates the supplementary functionalities of BDCR-FCLs as a multifaceted device towards the enhancement of the quality of supplied energy in terms of total harmonic distortion (THD) reduction, power factor (PF) correction, peak current reduction for nonlinear loads, and soft load variation effects, as well as their capability to limit fault current. To this aim, the capabilities of BDCR-FCLs have been studied through various simulated case studies in PSCAD/EMTDC software V5.0.1, in addition to experimental tests considering an AC microgrid connected to a DC system. The experimental and simulation investigations verify the superior multifaceted functionalities BDCR-FCLs introduce in addition to their excellent fault current-limiting capabilities. The results show that PF improved by 6.7% and 7%, respectively, in simulation and experimental tests. Furthermore, the current THD decreased by 20% and 18% in the simulation and experiment, respectively.","AC/DC microgrid; bridge-type DC reactor; fault current limiter","en","journal article","","","","","","","","","","","Intelligent Electrical Power Grids","","",""
"uuid:e9f814fb-1317-4820-b823-5d0a07ae3e4b","http://resolver.tudelft.nl/uuid:e9f814fb-1317-4820-b823-5d0a07ae3e4b","Can ChatGPT be used to predict citation counts, readership, and social media interaction? An exploration among 2222 scientific abstracts","de Winter, J.C.F. (TU Delft Human-Robot Interaction)","","2024","This study explores the potential of ChatGPT, a large language model, in scientometrics by assessing its ability to predict citation counts, Mendeley readers, and social media engagement. In this study, 2222 abstracts from PLOS ONE articles published during the initial months of 2022 were analyzed using ChatGPT-4, which used a set of 60 criteria to assess each abstract. Using a principal component analysis, three components were identified: Quality and Reliability, Accessibility and Understandability, and Novelty and Engagement. The Accessibility and Understandability of the abstracts correlated with higher Mendeley readership, while Novelty and Engagement and Accessibility and Understandability were linked to citation counts (Dimensions, Scopus, Google Scholar) and social media attention. Quality and Reliability showed minimal correlation with citation and altmetrics outcomes. Finally, it was found that the predictive correlations of ChatGPT-based assessments surpassed traditional readability metrics. The findings highlight the potential of large language models in scientometrics and possibly pave the way for AI-assisted peer review.","Citation prediction; Scientometrics; Altmetrics; ChatGPT; GPT-4; Scientific abstracts; Artificial intelligence","en","journal article","","","","","","","","","","","Human-Robot Interaction","","",""
"uuid:58bfa20f-4401-4782-a6b9-d3ae871a928d","http://resolver.tudelft.nl/uuid:58bfa20f-4401-4782-a6b9-d3ae871a928d","Rapid Aerostructural Optimization of Wing-Propeller Systems","Exalto, J.Q.B. (University of Michigan); Pacini, Bernardo (University of Michigan); Kaneko, Shugo (University of Michigan); Martins, Joaquim R. R. A. (University of Michigan); Hoogreef, M.F.M. (TU Delft Flight Performance and Propulsion)","","2024","Propeller-wing configurations are expected to return to the aviation industry due to their high propulsive efficiency and applicability in urban and regional air mobility. A knowledge gap exists around wing-propeller optimization because of the complexity of the propeller-wing system and the absence of a computationally efficient way to assess the coupled system. This paper addresses this gap by providing and validating a computationally efficient, mid-fidelity framework. The paper presents optimization results and recommendations for future iterations of the framework. The TU Delft PROWIM propeller is optimized with the framework, comparing sequential isolated optimization, trim optimization, and fully coupled optimization. The studies gives a conservative estimate of the efficiency gains that can be achieved by using coupled optimization, as compared to isolated optimization. Lastly, recommendations are given for future studies, such as including a battery weight model and including swirl velocities. It is expected that such model additions will affect the optimization results, and further emphasize the importance of coupled aerostructural optimization.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:e512b2fc-cf41-42a7-b288-19b7cc05ebc2","http://resolver.tudelft.nl/uuid:e512b2fc-cf41-42a7-b288-19b7cc05ebc2","Mobile atoms power up logical qubits","Terhal, B.M. (TU Delft Discrete Mathematics and Optimization)","","2024","Small groups of mobile neutral atoms have been manipulated with extraordinary control to form ‘logical’ quantum bits. These qubits can perform quantum computations more reliably than can individual atoms.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-29","","","Discrete Mathematics and Optimization","","",""
"uuid:c7da2dfd-9583-4fbd-ad8d-ef512be91c2f","http://resolver.tudelft.nl/uuid:c7da2dfd-9583-4fbd-ad8d-ef512be91c2f","Nudging human drivers via implicit communication by automated vehicles: Empirical evidence and computational cognitive modeling","Zgonnikov, A. (TU Delft Human-Robot Interaction); Beckers, N.W.M. (TU Delft Human-Robot Interaction); George, A. (TU Delft Human-Robot Interaction); Abbink, D.A. (TU Delft Human-Centred Artificial Intelligence; TU Delft Human-Robot Interaction); Jonker, C.M. (TU Delft Interactive Intelligence)","","2024","Understanding behavior of human drivers in interactions with automated vehicles (AV) can aid the development of future AVs. Existing investigations of such behavior have predominantly focused on situations in which an AV a priori needs to take action because the human has the right of way. However, future AVs might need to proactively manage interactions even if they have the right of way over humans, e.g., a human driver taking a left turn in front of the approaching AV. Yet it remains unclear how AVs could behave in such interactions and how humans would react to them. To address this issue, here we investigated behavior of human drivers (N = 19) when interacting with an oncoming AV during unprotected left turns in a driving simulator experiment. We measured the outcomes (Go or Stay) and timing of participants’ decisions when interacting with an AV which performed subtle longitudinal nudging maneuvers, e.g. briefly decelerating and then accelerating back to its original speed. We found that participants’ behavior was sensitive to deceleration nudges but not acceleration nudges. We compared the obtained data to predictions of several variants of a drift-diffusion model of human decision making. The most parsimonious model that captured the data hypothesized noisy integration of dynamic information on time-to-arrival and distance to a fixed decision boundary, with an initial accumulation bias towards the Go decision. Our model not only accounts for the observed behavior but can also flexibly generate predictions of human responses to arbitrary longitudinal AV maneuvers, and can be used for both informing future studies of human behavior and incorporating insights from such studies into computational frameworks for AV interaction planning.","Driver behavior; Automated vehicles; Implicit communication; Decision making; Cognitive modeling; Evidence accumulation","en","journal article","","","","","","","","","","","Human-Robot Interaction","","",""
"uuid:3b3ecab9-52a7-494d-b4bd-da74c126e39a","http://resolver.tudelft.nl/uuid:3b3ecab9-52a7-494d-b4bd-da74c126e39a","Microplastics van een textielwasserij en de verwijdering in een RWZI","Bertelkamp, Cheryl (Water Research Australia; Waternet); Pieke, Eelco (Het Waterlaboratorium); Struker, Andre (Waternet); Traast, Olivia (Waternet); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet)","","2024","Hoewel de rwzi’s Amsterdam-West en Horstermeer meer dan 99,8% van de microplastics verwijderen, blijft het absolute aantal dat in het milieu terechtkomt aanzienlijk. Tevens bleek dat één industriële textielwasserij verantwoordelijk is voor 13% van het totale aantal microplastics dat de rioolwaterzuivering binnenkomt.","","nl","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:271509df-a9db-4edd-b36d-268220064dee","http://resolver.tudelft.nl/uuid:271509df-a9db-4edd-b36d-268220064dee","Influence of geometrical levels of detail and inaccurate material optical properties on daylight simulation","Forouzandeh Shahraki, N. (TU Delft Environmental & Climate Design); Brembilla, E. (TU Delft Environmental & Climate Design); Nan, L. (TU Delft Urban Data Science); Stoter, J.E. (TU Delft Urban Data Science); Jakubiec, Alstan (University of Toronto)","","2024","Optimizing the built environment via simulations of building models hinges on standardizing data acquisition. In this research, we put forward distinct levels of detail for geometry and material inputs, specifically tailored for indoor daylight applications. We primarily focus on understanding the uncertainties arising from imprecise estimations of material optical properties and incomplete geometrical inputs in climate-based indoor daylight simulations. Employing a Monte Carlo approach, we analyzed six office and teaching spaces, creating 20 variations for each by altering geometrical completeness and material accuracy. The technique of excluding non-permanent objects below certain sizes in four graduated steps was used to derive and test the impact of various geometrical levels of detail. Our findings reveal that different levels of geometrical completeness lead to errors ranging from 1.08% to 18.05%. Additionally, a twofold increase in simulation time was noted when geometrical detail was enhanced relative to the most basic model. Errors stemming from imprecise definitions of material optical properties showed a normal distribution. The uncertainty in simulation outcomes showed a linear rise with increasing input material uncertainty, lying between 10% to 30%, depending on space configurations. We observed heightened uncertainty near openings, attributed to window transmittance effects. The research underscores that daylight predictions are markedly more sensitive to transmittance uncertainties than to those in reflectance, regardless of the window-to-floor ratio. These insights may help to guide a more efficient data acquisition process of indoor spaces for daylight simulations.","Digital twin; Digitization; Interior; LOD; Retrofit","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:1435f52e-84dd-49cb-8291-84b52b77d78b","http://resolver.tudelft.nl/uuid:1435f52e-84dd-49cb-8291-84b52b77d78b","Ontwikkelen in NYC is extreem, maar daardoor juist ook leerzaam","Janssen, C. (TU Delft Practice Chair Urban Area Development); Daamen, T.A. (TU Delft Urban Development Management); Heurkens, E.W.T.M. (TU Delft Urban Development Management)","","2024","Najaar 2023 gingen 20 professionals uit de Nederlandse ruimtelijke ontwikkelingspraktijk op studiereis naar New York. Een geliefde stad voor een onvergetelijke citytrip, maar wat levert zo’n studiereis op aan nieuwe inzichten voor gebiedsontwikkeling? Céline Janssen, Erwin Heurkens en Tom Daamen doen verslag.","international comparative research; gebiedsontwikkeling; lesson-drawing; New York","nl","report","Gebiedsontwikkeling.nu","","","","","","","","","","Practice Chair Urban Area Development","","",""
"uuid:e4491915-4e11-4518-aa31-67c1431a0109","http://resolver.tudelft.nl/uuid:e4491915-4e11-4518-aa31-67c1431a0109","Criminal, Cosmopolitan, Commodified: How Rotterdam’s Interwar Amusement Street, the Schiedamsedijk, Became a Safe Mirror Image of Itself","Baptist, V. (TU Delft History, Form & Aesthetics)","Blok, Gemma (editor); Oosterholt, Jan (editor)","2024","This chapter develops a layered analysis of the Schiedamsedijk, Rotterdam’s interwar amusement street. It links the street’s split socio-cultural character to that of port cities in general, and investigates this along the lines of a similar divide in perceptions of safety and security. Based on an historical bird’s-eye view of the pleasure area, the Schiedamsedijk’s criminal and cosmopolitan sides are discussed. Both of these maritime urban traits were neutralised when the Schiedamsedijk reinvented itself as a domestic tourist attraction in the late 1930s. Through visual sources, interchanges are foregrounded between contrasting internal and external perspectives on safety, which ultimately help to nuance and reframe the stereotypical characters and ambiguous nature traditionally ascribed to this historical environment of pleasure culture.","cosmopolitanism; interwar period; pleasure; port city; Rotterdam; safety","en","book chapter","Amsterdam University Press","","","","","'The Cultural Construction of Safety and Security' was made possible by a grant from: Open Access Stimuleringsfonds; HERA project ‘Governing the Narcotic City. Imaginaries, Practices, Discourses and Consequences of Public Drug Use’; Faculty CW Open Universiteit","","","","","History, Form & Aesthetics","","",""
"uuid:8d90896c-a188-4d33-928c-4f2a8054b9e3","http://resolver.tudelft.nl/uuid:8d90896c-a188-4d33-928c-4f2a8054b9e3","The Netherlands","Mostert, E. (TU Delft Water Resources)","Hellberg, Sofie (editor); Söderbaum, Fredrik (editor); Swain, Ashok (editor); Öjendal, Joakim (editor)","2024","","water; Netherlands; development; Dommel","en","book chapter","Routledge - Taylor & Francis Group","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-21","","","Water Resources","","",""
"uuid:c54f3785-0af4-43fe-ba50-7e0c320155d1","http://resolver.tudelft.nl/uuid:c54f3785-0af4-43fe-ba50-7e0c320155d1","Failure anticipation scheme in distribution systems based on wave distortions and Montecarlo methods","Bhandia, R. (TU Delft Intelligent Electrical Power Grids); de Jesus Chavez, Jose (TU Delft Intelligent Electrical Power Grids; Tecnologico de Monterrey); Cvetkovic, M. (TU Delft Intelligent Electrical Power Grids); Garcia-Vite, Pedro M. (Tecnológico Nacional de México Campus de Cd. Madero); Popov, M. (TU Delft Intelligent Electrical Power Grids); Palensky, P. (TU Delft Electrical Sustainable Energy)","","2024","Anticipating failures is vital for maintaining a reliable power supply. Advanced measurement devices in the grid generate vast data that contains valuable information on grid operations. Initial signatures of an incipient failure are often reflected in this data in the form of electrical waveform distortions. Conventional protection schemes are not equipped to analyze these distortions and anticipate failures. There is a considerable research gap for a simple yet robust and universal failure anticipation and diagnosis scheme. This paper proposes a universal Failure Anticipation and Diagnosis Scheme (FADS) to detect incipient failures in AC distribution grids. The method comprises three short stages, helping the operator make an informed decision. In the first stage, the FADS scheme leverages the fundamental properties of electrical sinusoid waveforms to detect distortions. In the second stage, the distortion data is processed through pre-determined thresholds set in accordance with the system's regular operation. In the third stage, depending on the system, the FADS uses the extent of the violations of these thresholds and ranks the severity of the danger posed to grid operations. The classification helps determine if the waveform distortions are the signature of an incipient failure. The proposed FADS method's reliability, robustness and effectiveness are evaluated in incipient failure conditions of field events modelled in real-time simulations on standardized IEEE distribution feeders. The FADS is a high-speed distortion detector, is quite sensitive, and the method has high selectivity because of its nature.","Incipient faults detection; Failure anticipation; Situational awareness; Signature analysis; Distribution systems","en","review","","","","","","","","","","Electrical Sustainable Energy","Intelligent Electrical Power Grids","","",""
"uuid:f8b4514f-c7f7-4a95-b0f4-e0f8d25da653","http://resolver.tudelft.nl/uuid:f8b4514f-c7f7-4a95-b0f4-e0f8d25da653","Changing Urban Temperature and Rainfall Patterns in Jakarta: A Comprehensive Historical Analysis","Maheng, M.D. (TU Delft Hydraulic Structures and Flood Risk; IHE Delft Institute for Water Education; Universitas Muhammadiyah Kendari); Bhattacharya, Biswa (IHE Delft Institute for Water Education); Zevenbergen, C. (TU Delft Urban Design; IHE Delft Institute for Water Education); Pathirana, Assela (IHE Delft Institute for Water Education)","","2024","The increasing global population and in-country migration have a significant impact on global land use land cover (LULC) change, which reduces green spaces and increases built-up areas altering the near-surface radiation and energy budgets, as well as the hydrological cycle over an urban area. The LULC change can lead to a combination of hazards such as increasing urban temperatures and intensified rainfall, ultimately resulting in increased flooding. This present study aims to discuss the changing pattern in urban temperature, daily rainfall, and flooding in Jakarta. The daily urban temperature and daily rainfall were based on a 30-year dataset from three meteorological stations of Jakarta in the period between 1987 and 2013. The changing trend was analyzed by using the Mann–Kendall and the Pettitt’s tests. The relation between daily rainfall and flooding was analyzed using a 30-year flooding dataset collected from several sources including the international disaster database, research, and newspaper. The results show that there was an increasing trend in the daily temperature and the daily rainfall in Jakarta. The annual maximum daily temperature showed that an increasing trend started in 2001 at the KMY station, and in 1996 at the SHIA station. In general, the highest annual maximum daily temperature was about 37 °C, while the lowest was about 33 °C. Moreover, the maximum daily rainfall started increasing from 2001. An increase in the maximum daily rainfall was observed mainly in January and February, which coincided with the flood events recorded in these months in Jakarta. This indicates that Jakarta is not only vulnerable to high urban temperature but also to flooding. While these two hazards occur in distinct timeframes, there is potential for their convergence in the same geographical area. This study provides new and essential insights to enhance urban resilience and climate adaptation, advocating a holistic approach required to tackle these combined hazards.","urbanization; land use land cover change; urban temperature; daily rainfall; flooding; Jakarta","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:a97d8a06-8661-4755-8548-350a7736ef6b","http://resolver.tudelft.nl/uuid:a97d8a06-8661-4755-8548-350a7736ef6b","Process competences to incorporate in higher education curricula","Nijhuis, S. A. (University of Twente); Endedijk, M. D. (University of Twente); Kessels, W. F. M. (University of Twente); Vrijhoef, R. (TU Delft Design & Construction Management)","","2024","This study reports on a survey on project managers' priorities. The survey used ISO 21500 as a scaffold to ask various respondents, like junior, experienced, and senior project managers, project sponsors, and students, to share their perceptions on the priorities for junior project managers. The respondent groups shared similar perceptions. Furthermore, project type and sector had little effect on junior project managers' priorities. Experienced and senior project managers shared their own priorities as well. The perceptions of priorities for junior, experienced, and senior project managers were mostly alike. However, experienced and senior project managers' priorities seemed slightly more affected by project type and sector. A session with experts in project management and teaching project management highlighted that the results for junior project managers could provide accents for introducing project management to students in higher education, provided the entire playing field of project management is also introduced.","Competences; Experience; Higher education; Processes; Project types; Respondent types","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:aeed12d4-3bde-4d73-a825-258aa615b5b5","http://resolver.tudelft.nl/uuid:aeed12d4-3bde-4d73-a825-258aa615b5b5","Approaching nearly zero energy of PV direct air conditioners by integrating building design, load flexibility and PCM","Li, Sihui (Changsha University of Science and Technology); Peng, Jinqing (Hunan University); Wang, Meng (Changsha University of Science and Technology); Wang, Kai (Hunan University); Li, Houpei (Hunan University); Lu, C.J. (TU Delft Environmental & Climate Design)","","2024","The energy matching of PV driven air conditioners is influenced by building load demand and PV generation. Merely increasing energy performance of building or PV capacity separately may improve the energy balance on a large time resolution, the real-time energy mismatching problem is still serious. In this study, a coordinated optimization method of PV capacity, building design, and load flexibility is proposed for improving the real-time energy matching of PVAC system. Then, a methodology integrating data mining method (XG Boost) and parametric simulation was developed to identify the determinant parameters of PV system and building design, exploring feature importance and correlations. The results of XG Boost indicate that the PV capacity, shape factor, and SHGC are the most critical factors. Finally, based on the optimized building design, the PCM layer was applied to improve the real time energy matching. To achieve a goal of 90 % ZEP, the PCM capacity can be decreased by 50.4 % and 62.8 % in Guangzhou and Shanghai in the optimized building. Moreover, the PV capacity can be reduced by 23 % in Guangzhou. The findings of this study provide practical guidance for designing PVAC system coupling with building design and energy storage devices.","PV direct driven air conditioner (PVAC); Zero energy buildings; Load flexibility; Building design","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-15","","","Environmental & Climate Design","","",""
"uuid:047fa48d-de15-43ef-b96c-31291d989b42","http://resolver.tudelft.nl/uuid:047fa48d-de15-43ef-b96c-31291d989b42","Unsupervised Learning for Public Transport Delay Pattern Analysis","Cheng, Y. (TU Delft Transport and Planning); Krishnakumari, P.K. (TU Delft Transport and Planning)","","2024","To analyze inherent and diverse patterns within line-based public transport daily delay occurrences, we introduce a data-driven exploratory analysis focused on the spatial-temporal distribution of these delays. Our approach relies on the utilization of the image pattern recognition technique and k-means clustering algorithm. We extract daily punctuality information from the automatic vehicle location data for a singular public transport route. This information is then translated into a visual representation through aggregated daily delay distribution profile images, offering insights into the spatial and temporal distribution of delays. The delay distribution finds expression in the arrangement of pixels within these profile images. The essence of these images is further distilled through image pattern recognition using the neural network architecture of ResNet50. Employing the k-means algorithm, we cluster these images based on their similarity, revealing five distinct daily delay patterns. The analysis of these patterns offers insight into their unique characteristics, yielding noteworthy outcomes. These findings hold the potential to provide public transport operators with an enriched comprehension of the dynamics of delays occurring on a specific line.","analytic data visualization; automatic vehicle location; data and data science; performance measures; public transportation; quality; visualization in transportation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-04","","Transport and Planning","Transport and Planning","","",""
"uuid:4729359e-3ef8-4a88-a8fe-88a820b54dc0","http://resolver.tudelft.nl/uuid:4729359e-3ef8-4a88-a8fe-88a820b54dc0","CasPEDIA Database: a functional classification system for class 2 CRISPR-Cas enzymes","Adler, Benjamin A. (University of California); Trinidad, Marena I. (University of California); Bellieny-Rabelo, Daniel (University of California); Zhang, Elaine (University of California); Karp, Hannah M. (University of California); Skopintsev, Petr (University of California); Thornton, Brittney W. (University of California); Yoon, Peter H. (University of California); Brouns, S.J.J. (TU Delft BN/Stan Brouns Lab; Kavli institute of nanoscience Delft)","","2024","CRISPR-Cas enzymes enable RNA-guided bacterial immunity and are widely used for biotechnological applications including genome editing. In particular, the Class 2 CRISPR-associated enzymes (Cas9, Cas12 and Cas13 families), have been deployed for numerous research, clinical and agricultural applications. However, the immense genetic and biochemical diversity of these proteins in the public domain poses a barrier for researchers seeking to leverage their activities. We present CasPEDIA (http://caspedia.org), the Cas Protein Effector Database of Information and Assessment, a curated encyclopedia that integrates enzymatic classification for hundreds of different Cas enzymes across 27 phylogenetic groups spanning the Cas9, Cas12 and Cas13 families, as well as evolutionarily related IscB and TnpB proteins. All enzymes in CasPEDIA were annotated with a standard workflow based on their primary nuclease activity, target requirements and guide-RNA design constraints. Our functional classification scheme, CasID, is described alongside current phylogenetic classification, allowing users to search related orthologs by enzymatic function and sequence similarity. CasPEDIA is a comprehensive data portal that summarizes and contextualizes enzymatic properties of widely used Cas enzymes, equipping users with valuable resources to foster biotechnological development. CasPEDIA complements phylogenetic Cas nomenclature and enables researchers to leverage the multi-faceted nucleic-acid targeting rules of diverse Class 2 Cas enzymes.","","en","journal article","","","","","","","","","","","BN/Stan Brouns Lab","","",""
"uuid:06f5905d-a350-43fd-af14-1d8422474a26","http://resolver.tudelft.nl/uuid:06f5905d-a350-43fd-af14-1d8422474a26","Housing inequalities: The space-time geography of housing policies","Nelson, R.J. (TU Delft Policy Analysis); Warnier, Martijn (TU Delft Multi Actor Systems); Verma, T. (TU Delft Policy Analysis)","","2024","Changes in policy over the last thirty years, particularly within advanced economies, have allowed for increased financialization, deregulation and globalisation of housing. What differentiates real-estate from other financial markets is that it possesses a salient socio-spatial geography. Housing inequalities are often framed as an outcome of macro-economic structural changes or as a product of local socio-spatial conditions, but the interactions between the two are less understood. To address this gap, we develop a descriptive methodology to connect the analysis of national housing policy trends in the Netherlands with local socio-spatial trajectories of neighbourhood change using nearly 20 years of historical data across a range of socio-spatial dimensions from the City of Rotterdam. Whilst nationally there has been an increasing policy preference for home ownership associated with a narrative of social upliftment, the spatial-temporal analysis reveals that the wealthiest neighbourhoods have benefitted significantly more from capital gains and increased rates of home ownership over time. Through descriptive analysis, the results highlight the role of divergent neighbourhood characteristics and path dependencies, suggesting that housing policies could benefit from the adoption of a more localised approach. Overall, the study sheds light on housing inequalities by integrating macro socio-economic factors with micro-level neighbourhood conditions.","Home ownership; Housing inequalities; Policy; Rotterdam; Spatial-temporal analysis","en","journal article","","","","","","","","","","Multi Actor Systems","Policy Analysis","","",""
"uuid:cecaa425-5484-40fa-8c27-a130fa014fe2","http://resolver.tudelft.nl/uuid:cecaa425-5484-40fa-8c27-a130fa014fe2","Cryogenic H-Bridge Converter for HTS Degaussing Application","Wikkerink, D.P. (TU Delft High Voltage Technology Group); Gagic, Mladen (TU Delft ESP LAB; TU Delft DC systems, Energy conversion & Storage); Mor, A. R. (Universitat Politécnica de Valencia); Polinder, H. (TU Delft Transport Engineering and Logistics); Ross, Robert (TU Delft Ship Hydromechanics and Structures; Institute for Science and Development)","","2024","A degaussing system can be used to reduce the detectability of the magnetic signature of a ship. Commonly, a degaussing system consists of a set of onboard copper coils that produce a magnetic field to compensate for the magnetic signature. High-temperature superconductive degaussing coils are considered an alternative to copper degaussing coils because of a reduction in energy losses, weight, volume, and costs. The losses of a high-temperature superconductor (HTS) degaussing system can be reduced even further by powering it with a cryocooled converter with parallel mosfets. A low-duty cycle and smaller current leads can be used. These solutions eliminate most of the power source losses. This article investigates such a cryocooled converter. The effect of the low switching frequency on the converter performance is tested. A prototype that can operate at cryogenic temperatures was built. The converter powers an HTS coil. It was found that a load current of 50 A can be achieved with a duty cycle of just 0.025 at an input voltage of 3.5 V while still meeting the requirement of a maximum current ripple of 0.5%. At a switching frequency higher than 100 Hz, the converter's performance deteriorates. Also, oscillations were observed in the circuit. This is a problem due to the low blocking voltage of the mosfets. The parasitic inductances in the circuit have a high impact on the performance because the resistance in the circuit is very low.","Converter; cryocooled electronics; cryostat; degaussing; high temperature superconductors; magnetic signature; parallel MOSFETs; ReBCO","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-30","","","High Voltage Technology Group","","",""
"uuid:29d02263-0699-4716-a460-ad53a87a1ab5","http://resolver.tudelft.nl/uuid:29d02263-0699-4716-a460-ad53a87a1ab5","Reliability updating for lateral failure of historic quay walls","Hemel, M. (TU Delft Hydraulic Engineering; TU Delft Amsterdam Institute for Advanced Metropolitan Solutions); Peters, D.J. (TU Delft Hydraulic Structures and Flood Risk; Royal HaskoningDHV); Schweckendiek, T. (TU Delft Hydraulic Structures and Flood Risk; Deltares); Jonkman, Sebastiaan N. (TU Delft Hydraulic Structures and Flood Risk)","","2024","The historic canal walls of Amsterdam, stretching 200 km in total, are constructed as a masonry wall on a timber deck supported by vertical timber piles. Understanding the resistance against lateral failure of these quays has been challenging due to uncertainties in their working principles, geometry, soil and structural properties. This paper proposes a Bayesian approach to include evidence from past loading situations and corresponding deformations into the reliability assessment. This approach enables refinement of the reliability predictions and parameter distribution uncertainties, leading to a more accurate prediction of the resistance against the lateral failure of historic quay wall. Depending on the type of evidence, an a-priori reliability prediction for a quay wall that fails to meet safety standards can be updated to any of the three consequence classes outlined in NEN8700. In a case study, a quay wall with an a-priori reliability of β = 1.5 has been increased to β = 3.2 by including evidence of an extreme survived load of 10 kN/m2 that resulted in displacements of less than 4 mm. This is a decrease in failure probability by two orders of magnitude, showing the potential impact of using observational information in combination with Bayesian updating.","bacterial deterioration; Bayesian approach; historic quay walls; lateral loaded timber piles; Reliability updating","en","journal article","","","","","","","","","","Hydraulic Engineering","Hydraulic Structures and Flood Risk","","",""
"uuid:a379dd7e-0cf9-4f42-98ed-abbed8cd8a67","http://resolver.tudelft.nl/uuid:a379dd7e-0cf9-4f42-98ed-abbed8cd8a67","Enhanced isobutanol recovery from fermentation broth for sustainable biofuels production","Jankovic, T.J. (TU Delft BT/Bioprocess Engineering); Straathof, Adrie J.J. (TU Delft BT/Bioprocess Engineering); Kiss, A.A. (TU Delft ChemE/Product and Process Engineering)","","2024","Isobutanol is a highly attractive renewable alternative to conventional fossil fuels, with superior fuel properties as compared to ethanol and 1-butanol. Even though the isobutanol production by fermentation has significant potential, complex downstream processing is limiting the wide-spreading of this technology. Accordingly, this original research significantly contributes to the advancement in industrial biofuel production by developing two eco-efficient downstream processes for the industrial-scale recovery of isobutanol (production capacity 50 ktonneIBUT/y), from a highly dilute fermentation broth (>98 wt% water). Vacuum distillation and a novel hybrid combination of gas stripping and vacuum evaporation were coupled with atmospheric azeotropic distillation to recover over 99.9 % of isobutanol as a high-purity product (100 wt%). Advanced heat pumping and heat integration techniques were further implemented to allow the complete electrification of these recovery processes. Furthermore, implementation of these techniques significantly decreased total annual costs (0.131–0.161 $/kgIBUT), reduced energy requirements (0.488–0.807 kWeh/kgIBUT) and lowered CO2 emissions (0.303–0.449 kgCO2/kgIBUT), resulting in highly competitive purification processes. In addition to efficiently recovering isobutanol, the designed downstream processes provide the potential to enhance the fermentation process by recycling all present microorganisms and reducing water demand. Therefore, the results of this original research substantially contribute to the advancement in industrial biotechnology and the wide-spreading of biofuel production.","Biofuels; Dividing-wall column; Downstream processing; Gas stripping with vacuum evaporation; Industrial biotechnology; Isobutanol","en","journal article","","","","","","","","","","","BT/Bioprocess Engineering","","",""
"uuid:c58a673f-5b77-4a7a-a516-328415bceb7f","http://resolver.tudelft.nl/uuid:c58a673f-5b77-4a7a-a516-328415bceb7f","Impact of the COVID-19 pandemic on the in-hospital diagnostic pathway of breast and colorectal cancer in the Netherlands: A population-based study","Wolfkamp, Wouter (University of Twente; Netherlands Comprehensive Cancer Organisation (IKNL)); Meijer, Joyce (University of Twente; Netherlands Comprehensive Cancer Organisation (IKNL)); van Hoeve, Jolanda C. (University of Twente; Netherlands Comprehensive Cancer Organisation (IKNL)); van Erning, Felice (Netherlands Comprehensive Cancer Organisation (IKNL); Catharina Cancer Institute, Eindhoven); de Geus-Oei, L.F. (TU Delft RST/Radiation, Science and Technology; Leiden University Medical Center; University of Twente); de Hingh, Ignace (Universiteit Maastricht; Netherlands Comprehensive Cancer Organisation (IKNL); Catharina Cancer Institute, Eindhoven); Veltman, Jeroen (University of Twente; ZGT, Almelo); Siesling, Sabine (University of Twente; Netherlands Comprehensive Cancer Organisation (IKNL))","","2024","Background: In the Netherlands, the COVID-19 pandemic resulted in a temporary halt of population screening for cancer and limited hospital capacity for non-COVID care. We aimed to investigate the impact of the pandemic on the in-hospital diagnostic pathway of breast cancer (BC) and colorectal cancer (CRC). Methods: 71,159 BC and 48,900 CRC patients were selected from the Netherlands Cancer Registry. Patients, diagnosed between January 2020 and July 2021, were divided into six periods and compared to the average of patients diagnosed in the same periods in 2017–2019. Diagnostic procedures performed were analysed using logistic regression. Lead time of the diagnostic pathway was analysed using Cox regression. Analyses were stratified for cancer type and corrected for age, sex (only CRC), stage and region. Results: For BC, less mammograms were performed during the first recovery period in 2020. More PET-CTs were performed during the first peak, first recovery and third peak period. For CRC, less ultrasounds and more CT scans and MRIs were performed during the first peak. Lead time decreased the most during the first peak by 2 days (BC) and 8 days (CRC). Significantly fewer patients, mainly in lower stages, were diagnosed with BC (−47%) and CRC (−36%) during the first peak. Conclusion: Significant impact of the COVID-19 pandemic was found on the diagnostic pathway, mainly during the first peak. In 2021, care returned to the same standards as before the pandemic. Long-term effects on patient outcomes are not known yet and will be the subject of future research.","breast cancer; colorectal cancer; COVID-19; diagnosis; diagnostic pathway; diagnostic procedures; lead time; population based","en","journal article","","","","","","","","","","RST/Radiation, Science and Technology","","","",""
"uuid:79f41801-69d9-4359-9b1e-4ad53efe9948","http://resolver.tudelft.nl/uuid:79f41801-69d9-4359-9b1e-4ad53efe9948","Author Correction: Origin of fast charging in hard carbon anodes (Nature Energy, (2024), 10.1038/s41560-023-01414-5)","Vasileiadis, A. (TU Delft RST/Storage of Electrochemical Energy); Zhou, Q. (TU Delft Design Conceptualization and Communication; Chinese Academy of Sciences); Lu, Yaxiang (Chinese Academy of Sciences); Li, Y. (TU Delft Aerospace Engineering/International Space University; Chinese Academy of Sciences; University of Chinese Academy of Sciences); Ombrini, P. (TU Delft RST/Storage of Electrochemical Energy); Chen, Z. (TU Delft Electronic Instrumentation; Chinese Academy of Sciences; University of Chinese Academy of Sciences); van der Jagt, R. (TU Delft RST/Storage of Electrochemical Energy); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2024","Correction to: Nature Energy, published online 3 January 2024. In the version of this article initially published, lithium (green, “Li”) and sodium (purple, “Na”) color key labels in Fig. 3a,d,e were interchanged and are now amended in the HTML and PDF versions of the article.","","en","journal article","","","","","","Corrigendum voor DOI 10.1038/s41560-023-01414-5","","2024-07-03","","Aerospace Engineering/International Space University","RST/Storage of Electrochemical Energy","","",""
"uuid:7d7185c8-44e4-4e25-951d-a7d30a3dc642","http://resolver.tudelft.nl/uuid:7d7185c8-44e4-4e25-951d-a7d30a3dc642","An automated slide scanning system for membrane filter imaging in diagnosis of urogenital schistosomiasis","Oyibo, P.O. (TU Delft Team Michel Verhaegen); Agbana, T.E. (TU Delft Team Michel Verhaegen); van Lieshout, Lisette (Leiden University Medical Center); Oyibo, Wellington (University of Lagos); Diehl, J.C. (TU Delft Design for Sustainability); Vdovin, Gleb (TU Delft Team Michel Verhaegen)","","2024","Traditionally, automated slide scanning involves capturing a rectangular grid of field-of-view (FoV) images which can be stitched together to create whole slide images, while the autofocusing algorithm captures a focal stack of images
to determine the best in-focus image. However, these methods can be timeconsuming due to the need for X-, Y- and Z-axis movements of the digital microscope while capturing multiple FoV images. In this paper, we propose a solution to minimise these redundancies by presenting an optimal procedure for automated slide scanning of circular membrane filters on a glass slide. We achieve this by following an optimal path in the sample plane, ensuring that only FoVs overlapping the filter membrane are captured. To capture the best infocus FoV image, we utilise a hill-climbing approach that tracks the peak of the mean of Gaussian gradient of the captured FoVs images along the Z-axis. We implemented this procedure to optimise the efficiency of the Schistoscope, an automated digital microscope developed to diagnose urogenital schistosomiasis by imaging Schistosoma haematobium eggs on 13 or 25 mm membrane filters. Our improved method reduces the automated slide scanning time by 63.18%and 72.52% for the respective filter sizes. This advancement greatly supportsthe practicality of the Schistoscope in large-scale schistosomiasis monitoringand evaluation programs in endemic regions. This will save time, resources andalso accelerate generation of data that is critical in achieving the targets for schistosomiasis elimination.","autofocusing; automated slide scanning; digital microscope; schistosomiasis; whole slide imaging This","en","journal article","","","","","","","","","","","Team Michel Verhaegen","","",""
"uuid:1a7de9df-ca56-4691-bdef-74a55c2f3887","http://resolver.tudelft.nl/uuid:1a7de9df-ca56-4691-bdef-74a55c2f3887","Activating business models for condominium renovations: Identification of viable business models for Integrated Home Renovation Services for condominiums in the Netherlands and Flanders D2.2","Elgendy, R. (TU Delft Real Estate Management); Mlecnik, E. (TU Delft Real Estate Management)","","2024","The need for energy efficient buildings has become increasingly important in climate change mitigation. Almost 75% of the building stock in Europe is energy inefficient. Residential buildings are responsible for 27% of the total energy consumption in Europe. Integrated home renovation services (IHRS) have emerged as a potential solution to accelerate highly energy-efficient renovations for homeowners’ associations (HOAs). The question arises: How can the business models of current IHRS accelerate highly energy-efficient renovations by HOAs? This report explores the current state of IHRS in Europe with a focus on the viewpoint of the Netherlands and Flanders. The methods used are desk research, questionnaires and interviews. Five business models (BMs) of CondoReno project partners were analyzed, to support their development strategies within the regional context. This report compares IHRS BMs and brings knowledge about the operation of IHRS. The results show that the BMs of the project partners share some similarities and differ in other aspects. Regarding the similarities, all five providers share the value of offering customized energy renovation packages, also in terms of customer segments, by addressing the specific needs of HOAs. They slightly differ regarding the channels used, customer relationships, key resources, key activities and key partners. They differ in revenue/value streams and cost structure, owing to context-specific aspects of the type of organization. As such, this study informs stakeholders about the development of effective and targeted IHRS initiatives in the EU.","business models; integrated home renovation services; renovation; homeowner associations; condominium; energy efficiency","en","report","CondoReno","","","","","","","","","","Real Estate Management","","",""
"uuid:4d8724f7-f7b6-4a8d-86b5-b52cd5097797","http://resolver.tudelft.nl/uuid:4d8724f7-f7b6-4a8d-86b5-b52cd5097797","Photo-oxidation of Micro-and Nanoplastics: Physical, Chemical, and Biological Effects in Environments","Xu, Yanghui (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Ou, Q. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet); Liu, G. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Lompe, K.M. (TU Delft Sanitary Engineering)","","2024","Micro- and nanoplastics (MNPs) are attracting increasing attention due to their persistence and potential ecological risks. This review critically summarizes the effects of photo-oxidation on the physical, chemical, and biological behaviors of MNPs in aquatic and terrestrial environments. The core of this paper explores how photo-oxidation-induced surface property changes in MNPs affect their adsorption toward contaminants, the stability and mobility of MNPs in water and porous media, as well as the transport of pollutants such as organic pollutants (OPs) and heavy metals (HMs). It then reviews the photochemical processes of MNPs with coexisting constituents, highlighting critical factors affecting the photo-oxidation of MNPs, and the contribution of MNPs to the phototransformation of other contaminants. The distinct biological effects and mechanism of aged MNPs are pointed out, in terms of the toxicity to aquatic organisms, biofilm formation, planktonic microbial growth, and soil and sediment microbial community and function. Furthermore, the research gaps and perspectives are put forward, regarding the underlying interaction mechanisms of MNPs with coexisting natural constituents and pollutants under photo-oxidation conditions, the combined effects of photo-oxidation and natural constituents on the fate of MNPs, and the microbiological effect of photoaged MNPs, especially the biotransformation of pollutants.","Microplastics; Photo-oxidation; Physical Effects; Photochemical Processes","en","review","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:d282e08e-6348-434b-b9c8-f3436b727341","http://resolver.tudelft.nl/uuid:d282e08e-6348-434b-b9c8-f3436b727341","Reviews and responses for Compilation of an open-source traffic and CO2 emissions dataset for commercial aviation","Salgas, A. (Université de Toulouse); Sun, Junzi (TU Delft Control & Simulation); Delbecq, Scott (Université de Toulouse); Planès, Thomas (Université de Toulouse); Lafforgue, Gilles (Université de Toulouse)","Catarino Soares Franco, A.M. (editor); Li, Max (editor); Strohmeier, Martin (editor)","2024","","Open-data; Emissions; Air Traffic","en","contribution to periodical","","","","","","","","","","","Control & Simulation","","",""
"uuid:accfe314-6066-4eb5-ad14-04fad3e0f168","http://resolver.tudelft.nl/uuid:accfe314-6066-4eb5-ad14-04fad3e0f168","The Slow and The Furious? Performance Antipattern Detection in Cyber-Physical Systems","van Dinten, I. (TU Delft Software Engineering); Derakhshanfar, Pouria (JetBrains Research); Panichella, A. (TU Delft Software Engineering); Zaidman, A.E. (TU Delft Software Technology)","","2024","Cyber-Physical Systems (CPSs) have gained traction in recent years. A major non-functional quality of CPS is performance since it affects both usability and security. This critical quality attribute depends on the specialized hardware, simulation engines, and environmental factors that characterize the system under analysis. While a large body of research exists on performance issues in general, studies focusing on performance-related issues for CPSs are scarce. The goal of this paper is to build a taxonomy of performance issues in CPSs. To this aim, we present two empirical studies aimed at categorizing common performance issues (Study I) and helping developers detect them (Study II). In the first study, we examined commit messages and code changes in the history of 14 GitHub-hosted open-source CPS projects to identify commits that report and fix self-admitted performance issues. We manually analyzed 2699 commits, labeled them, and grouped the reported performance issues into antipatterns. We detected instances of three previously reported Software Performance Antipatterns (SPAs) for CPSs. Importantly, we also identified new SPAs for CPSs not described earlier in the literature. Furthermore, most performance issues identified in this study fall into two new antipattern categories: Hard Coded Fine Tuning (399 of 646) and Magical Waiting Number (150 of 646). In the second study, we introduce static analysis techniques for automatically detecting these two new antipatterns; we implemented them in a tool called AP-Spotter. We analyzed 9 open-source CPS projects not utilized to build the SPAs taxonomy to benchmark AP-Spotter. Our results show that AP-Spotter achieves 62.04% precision in detecting the antipatterns","Software performance antipatterns; Cyber-Physical Systems; Antipattern Detection; Software Maintenance; Empirical Software Engineering; Static Analysis","en","journal article","","","","","","","","","","Software Technology","Software Engineering","","",""
"uuid:57935769-3408-47fa-9347-19e1393b9cbb","http://resolver.tudelft.nl/uuid:57935769-3408-47fa-9347-19e1393b9cbb","The SATA-Drive: A Modular Robotic Drive for Reusable Steerable Laparoscopic Instruments","Lenssen, T.A. (TU Delft Medical Instruments & Bio-Inspired Technology); Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology); Horeman, T. (TU Delft Medical Instruments & Bio-Inspired Technology)","","2024","Introduction: Most robotic instruments and their drives still risk residual contamination due to cleaning complexities, rendering them limited reusable, and tend to have larger instruments than the 5mm laparoscopic standard. The novel steerable laparoscopic SATA-LRS uses modularity for cleanability and exchangeability. The SATA-Drive: a robotic driver designed for the actuation of a 3mm scaled version of the SATA-LRS is presented. Methods: A modular, expandable gear mechanism was designed to efficiently rotate and translate the instrument shafts. The 3mm SATA-LRS is controlled as proof. An user-experiment is conducted to test the (de)coupling of the instrument to and from the drive. Results: A video shows the SATA-Driver successfully articulating, rotating and grasping the end-effector. End-effector dis- and reassembly is possible in 36 (13 SD) seconds, while complete instrument coupling requires 28(8 SD) seconds and de-coupling requires 16 (7 SD) seconds. Discussion: A non-surgical robot arm, mounted with the SATA-drive has effectively been transformed into a system similar to robot assisted laparoscopy. The modularity of the drive's segmented build can easily be adapted and could benefit the adoption of future instruments. The SATA-LRS's cleanability features and its end-effector changes without disassembly are expected to benefit medical robotics. The 3mm SATA-LRS shows the instrument's potential for mini-laparoscopy.","Driver; End effectors; Gears; Grasping; Instrument; Instruments; Laparoscopes; Laparoscopy; RAS; SATA; Shafts; Surgery","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:3ac4d7bc-3fcf-4d1c-89ac-731b7ab40b76","http://resolver.tudelft.nl/uuid:3ac4d7bc-3fcf-4d1c-89ac-731b7ab40b76","Collective action lessons for the energy transition: learning from social movements of the past","Pearce, B.J. (TU Delft Policy Analysis); Djinlev, Vanja (ETH Zürich)","","2024","To accelerate the energy transition and achieve the needed large-scale transformation to address climate change, different barriers including lock-ins and path dependencies, incumbent power structures and changing individual and collective norms, values, and behaviors around energy need to be addressed. In the face of these challenges, citizens are beginning to play a bigger role in the transformation of the energy system. For example, they are becoming prosumers (energy consumers who also produce energy) and are increasingly engaging in collective energy actions, including taking part in energy communities. In the latter instance, collective investment and consumption decisions are made together, and norms, understanding and behavior towards energy are shaped collectively. To better understand the roles that individuals and groups can play in confronting the challenges of the energy transition, we make use of and adapt Ostrom’s socio-ecological systems (SES) framework to analyze past examples of collective actions and to delve deeper into the causes and catalysts of collective actions. We show how this framework can be used to analyze collective actions across time and contexts, focusing on connecting individual and group behavior with changing societal norms and the corresponding barriers to change. By applying the adapted SES framework as a lens to analyze historical examples of collective actions that have resulted in a widespread transformation in social norms and structures, we identify similarities and differences between these case studies and the current energy transition. Confronting incumbents and the challenge of changing social norms and behaviors are among the similarities, but the specific tactics used to limit incumbents’ powers and the actions taken to influence the norms and behaviors differ. Lastly, we determine the key actors that influenced social and behavioral change, as one of the main outcomes of the analysis.","","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:c9638625-6c82-4180-9c4f-929d311ebf11","http://resolver.tudelft.nl/uuid:c9638625-6c82-4180-9c4f-929d311ebf11","Examining the Interplay Between National Strategies and Value Change in the Battle Against COVID-19: An Agent-Based Modelling Inquiry","Ale Ebrahim Dehkordi, Molood (TU Delft Energie and Industrie); Melnyk, A. (TU Delft Ethics & Philosophy of Technology); Ghorbani, Amineh (TU Delft System Engineering); Herder, P.M. (TU Delft Energy Technology)","","2024","Social disruptions caused by the COVID-19 pandemic challenged existing institutional arrangements that govern the society. During that time, nation-states had to prevent the collapse of society and rapidly establish new institutions and adapt existing ones to address public health, job security, and freedom-of-movement concerns. At the same time, institutional developments are explicitly or implicitly related to the cultural and moral values relevant to societal well-being. Values hold a significant role in governing society during crises, guiding states' institutional response to unforeseen challenges. However, values themselves are not static: research has shown that values may change rapidly during crises. This paper studies the relationship between value change and institutional change in times of crisis using agent-based modelling and machine learning techniques. In our model, we represent countries as agents who define institutional strategies to control disease spread and subsequently protect the well-being of their citizens. Institutional change and value change are modelled as two independent processes. Yet, the model confirms the seemingly trivial inverse correlation between them: when the value of openness-to-change increases in a society, the institutional strategies also become less strict. Conversely, when conservatism increases, the strategies become stricter on average. However, there is no direct causal relationship between the two changes: being open to change does not necessarily make a government select more relaxed rules, but this correlation is rather an emergent consequence of being more flexible in changing rules, whether the new ones are stricter or more relaxed.","Institutional modelling; values; value change; Institutional evolution; crisis","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:ce41e552-b804-4420-a59d-6fc661984561","http://resolver.tudelft.nl/uuid:ce41e552-b804-4420-a59d-6fc661984561","Long-term stability, noise, and temperature sensitivity of modular porous-pot electrodes designed for geophysical and geotechnical applications, and details of their construction","Comeau, M.J. (TU Delft Applied Geophysics and Petrophysics); Ueding, Stefan (University of Münster); Becken, Michael (University of Münster)","","2024","Electrodes are used to measure a potential difference between two points. In geophysical and geotechnical applications they are often in the form of non-polarizable porous-pot electrodes. Here we describe the design, construction, and testing of modular and refillable electrodes, which facilitates repair as the electrodes degrade over time. We use a chemical composition based on a metal in contact with an over-saturated electrolyte that consists of a salt of that metal and an auxiliary salt. We compare characteristics when the electrolyte is stabilized in a clay or not, and with various states of ceramic porous plugs and two types of wood plugs. Next, we assess the long-term stability (more than 1 month), noise (periods of 1 s to 1 hr), and temperature sensitivity of different types of electrodes. Electrodes with an electrolyte and clay formula showed lower noise (0.2–0.4 μV at periods of 1–120 s), greater long-term stability (0.05–0.5 mV/month of smooth drift), and greater consistency between samples measured than those with no clay (noise and drift values up to four times larger). The effects from different porous plugs were negligible, with similar results for ceramic and wood types. The temperature sensitivity of the electric potential was assessed, from −3 to 35°C. All electrodes showed a temperature sensitivity of about −30 μV/°C. This is considered very low compared to some commercially available electrodes. Finally, continuous long-term laboratory and field measurements of the potential highlight the application of the new electrodes.","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:6c62e06a-8a1b-4000-923b-c01948515e28","http://resolver.tudelft.nl/uuid:6c62e06a-8a1b-4000-923b-c01948515e28","Identifying the most important facilitators of open research data sharing and reuse in Epidemiology: A mixed-methods study","Zuiderwijk-van Eijk, A.M.G. (TU Delft Information and Communication Technology); Türk, Berkay Onur (Eindhoven University of Technology)","","2024","To understand how open research data sharing and reuse can be further improved in the field of Epidemiology, this study explores the facilitating role that infrastructural and institutional arrangements play in this research discipline. It addresses two research questions: 1) What influence do infrastructural and institutional arrangements have on open research data sharing and reuse practices in the field of Epidemiology? And 2) how could infrastructural and institutional instruments used in Epidemiology potentially be useful to other research disciplines? First, based on a systematic literature review, a conceptual framework of infrastructural and institutional instruments for open research data facilitation is developed. Second, the conceptual framework is applied in interviews with Epidemiology researchers. The interviews show that two infrastructural and institutional instruments have a very high influence on open research data sharing and reuse practices in the field of Epidemiology, namely (a) access to a powerful search engine that meets open data search needs and (b) support by data stewards and data managers. Third, infrastructural and institutional instruments with a medium, high, or very high influence were discussed in a research workshop involving data stewards and research data officers from different research fields. This workshop suggests that none of the influential instruments identified in the interviews are specific to Epidemiology. Some of our findings thus seem to apply to multiple other disciplines. This study contributes to Science by identifying field-specific facilitators and challenges for open research data in Epidemiology, while at the same time revealing that none of the identified influential infrastructural and institutional instruments were specific to this field. Practically, this implies that open data infrastructure developers, policymakers, and research funding organizations may apply certain infrastructural and institutional arrangements to multiple research disciplines to facilitate and enhance open research data sharing and reuse.","","en","journal article","","","","","","","","","","","Information and Communication Technology","","",""
"uuid:a3c3ff9c-45bb-428e-8511-07b84c9f8523","http://resolver.tudelft.nl/uuid:a3c3ff9c-45bb-428e-8511-07b84c9f8523","How should an AI trust its human teammates? Exploring possible cues of artificial trust","Centeio Jorge, C. (TU Delft Interactive Intelligence); Jonker, C.M. (TU Delft Interactive Intelligence); Tielman, M.L. (TU Delft Interactive Intelligence)","","2024","In teams composed of humans, we use trust in others to make decisions, such as what to do next, who to help and who to ask for help. When a team member is artificial, they should also be able to assess whether a human teammate is trustworthy for a certain task. We see trustworthiness as the combination of (1) whether someone will do a task and (2) whether they can do it. With building beliefs in trustworthiness as an ultimate goal, we explore which internal factors (krypta) of the human may play a role (e.g., ability, benevolence, and integrity) in determining trustworthiness, according to existing literature. Furthermore, we investigate which observable metrics (manifesta) an agent may take into account as cues for the human teammate’s krypta in an online 2D grid-world experiment (n = 54). Results suggest that cues of ability, benevolence and integrity influence trustworthiness. However, we observed that trustworthiness is mainly influenced by human’s playing strategy and cost-benefit analysis, which deserves further investigation. This is a first step towards building informed beliefs of human trustworthiness in human-AI teamwork.","","en","journal article","","","","","","","","","","","Interactive Intelligence","","",""
"uuid:c5b333c8-3824-4b11-95ba-13fa75f0d344","http://resolver.tudelft.nl/uuid:c5b333c8-3824-4b11-95ba-13fa75f0d344","Asgard/NOTT: L-band nulling interferometry at the VLTI. II. Warm optical design and injection system","Garreau, Germain (Katholieke Universiteit Leuven); Bigioli, Azzurra (Katholieke Universiteit Leuven); Laugier, Romain (Katholieke Universiteit Leuven); Raskin, Gert (Katholieke Universiteit Leuven); Morren, Johan (Katholieke Universiteit Leuven); Berger, Jean Philippe (Université Grenoble Alpes); Dandumont, Colin (Université de Liège); Goldsmith, Harry-Dean Kenchington (Australian National University); Loicq, J.J.D. (TU Delft Spaceborne Instrumentation)","","2024","Asgard/NOTT (previously Hi-5) is a European Research Council (ERC)-funded project hosted at KU Leuven and a new visitor instrument for the Very Large Telescope Interferometer (VLTI). Its primary goal is to image the snow line region around young stars using nulling interferometry in the L′-band (3.5 to 4.0) μm, where the contrast between exoplanets and their host stars is advantageous. The breakthrough is the use of a photonic beam combiner, which only recently allowed the required theoretical raw contrast of 10−3 in this spectral range. Nulling interferometry observations of exoplanets also require a high degree of balancing between the four pupils of the VLTI in terms of intensity, phase, and polarization. The injection into the beam combiner and the requirements of nulling interferometry are driving the design of the warm optics and the injection system. The optical design up to the beam combiner is presented. It offers a technical solution to efficiently couple the light from the VLTI into the beam combiner. During the coupling, the objective is to limit throughput losses to 5% of the best expected efficiency for the injection. To achieve this, a list of different loss sources is considered with their respective impact on the injection efficiency. Solutions are also proposed to meet the requirements of beam balancing for intensity, phase, and polarization. The different properties of the design are listed, including the optics used, their alignment and tolerances, and their impact on the instrumental performances in terms of throughput and null depth. The performance evaluation gives an expected throughput loss <6.4% of the best efficiency for the injection and a null depth of ∼2.10−3, mainly from optical path delay errors outside the scope of this work","","en","journal article","","","","","","","","","","","Spaceborne Instrumentation","","",""
"uuid:052cb2b0-287f-4818-ab32-ce44b954320b","http://resolver.tudelft.nl/uuid:052cb2b0-287f-4818-ab32-ce44b954320b","Developing reusable packaging for FMCG: Consumers’ perceptions of benefits and risks of refillable and returnable packaging systems","Miao, X. (TU Delft Marketing and Consumer Research); Magnier, L.B.M. (TU Delft Marketing and Consumer Research); Mugge, R. (TU Delft Design, Organisation and Strategy)","Hideki, Kobayashi (editor); Shinichi, Fukushige (editor); Eiji, Yamasue (editor); Keishiro, Hara (editor)","2024","This research investigates consumers’ perception of two main types of reusable packaging systems: refillable and returnable packaging systems. An online experiment was conducted with Dutch consumers (n=250) in which attitudinal and behavioural responses to two reusable packaging systems were compared to the responses to disposable packaging. We created three types of packaging (disposable, refillable and returnable) for either food (ketchup) and non-food (shampoo) products. Results showed that consumers evaluate refillable and returnable packaging positively. Three benefits (environmental benefits, anticipated conscience and enjoyment) and three risks (contamination, complexity and performance risks) of reusable packaging are measured in this study. This research contributes to theunderstanding of consumers’ perception of reusable packaging systems, which can help future designers and companies to design their systems more effectively.","Reuse; Benefits and risks; consumer behaviour; Circular economy; Returnable packaging; Refillable packaging","en","book chapter","Springer Nature","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-17","","Design, Organisation and Strategy","Marketing and Consumer Research","","",""
"uuid:fe50979a-2553-453b-8cf7-c9757453ff19","http://resolver.tudelft.nl/uuid:fe50979a-2553-453b-8cf7-c9757453ff19","Engineering ssRNA tile filaments for (dis)assembly and membrane binding","De Franceschi, N. (TU Delft BN/Cees Dekker Lab); Hoogenberg, B. (TU Delft BN/Cees Dekker Lab); Katan, A.J. (TU Delft QN/Afdelingsbureau); Dekker, C. (TU Delft BN/Cees Dekker Lab)","","2024","Cytoskeletal protein filaments such as actin and microtubules confer mechanical support to cells and facilitate many cellular functions such as motility and division. Recent years have witnessed the development of a variety of molecular scaffolds that mimic such filaments. Indeed, filaments that are programmable and compatible with biological systems may prove useful in studying or substituting such proteins. Here, we explore the use of ssRNA tiles to build and modify filaments in vitro. We engineer a number of functionalities that are crucial to the function of natural proteins filaments into the ssRNA tiles, including the abilities to assemble or disassemble filaments, to tune the filament stiffness, to induce membrane binding, and to bind proteins. This work paves the way for building dynamic cytoskeleton-mimicking systems made out of rationally designed ssRNA tiles that can be transcribed in natural or synthetic cells.","","en","journal article","","","","","","","","","","","BN/Cees Dekker Lab","","",""
"uuid:4756c84a-1d2a-4315-86aa-2596d411f1f2","http://resolver.tudelft.nl/uuid:4756c84a-1d2a-4315-86aa-2596d411f1f2","Mapping Contextual Factors Influencing Physical Activity Behavior of People with a Physical Demanding Job","Beckmann, Julia (Student TU Delft); Coenen, Pieter (Amsterdam UMC); Speklé, Erwin (Arbo Unie, Utrecht); Kraal, J.J. (TU Delft Applied Ergonomics and Design)","Melles, Marijke (editor)","2024","People with a physically demanding job have an unhealthy disbalance in occupational and leisure-time physical activity (PA). We aimed to understand which contextual factors influence this disbalance, and explore opportunities for lifestyle interventions that could restore this disbalance. We applied a contextmapping study with six production workers from a Dutch coating department. Participants filled in a sensitizing booklet with PA-related activities, and were interviewed afterwards. Participants reported reasons for (not) being active in leisure-time using an experience sampling method. Our results indicate that main reasons for being inactive during leisure time were their believes that occupational PA is enough for a healthy lifestyle, and the need to rest after work. Results show that lifestyle interventions should tackle workers inadequate risk perception and over-exhaustion to empower them to shift their PA behavior in a healthier direction. This indicates the need for a holistic approach targeting both home and working environments.","Holistic approach; Life-long health; Lifestyle intervention; Occupational health; Physical activity paradox; Prevention","en","book chapter","Springer Nature","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-05","","","Applied Ergonomics and Design","","",""
"uuid:09abe37f-d7e9-4394-af5e-fbda94deb290","http://resolver.tudelft.nl/uuid:09abe37f-d7e9-4394-af5e-fbda94deb290","Comparing the Active, Functional, and Passive Range of Motion of Finger Joints Using Dynamic Measurement","Yuan, Tianyun (Student TU Delft); Song, Yu (Student TU Delft); Goossens, R.H.M. (TU Delft Human-Centered Design; TU Delft Applied Ergonomics and Design); Kraan, G.A. (TU Delft Applied Ergonomics and Design; Reinier de Graaf Gasthuis)","Melles, Marijke (editor)","2024","Studies on finger kinematics, especially the range of motion (RoM) measurements, are essential to understand the use of finger joints and the pathology of related disease. Limited literatures compared the active RoM (A-RoM) of finger joints with either their functional RoM (F-RoM) or passive RoM (p-RoM) using different measuring protocols and tools. This study aims to provide an overall comparison including all three types of RoMs. We measured A-RoM, F-RoM, and P-RoM, using a dynamic measurement system. Our goal is to investigate the relationships among the three RoMs by comparing their extreme rotation angles. The results suggested that P-RoM was the largest motion range, and F-RoM can exceed their A-RoM. The F-RoM of distal-interphalangeal joints may rotated 8–20° more than their A-RoM, mainly during precise and power manipulations. Besides to A-RoM, knowledge of F-RoM and P-RoM are also important for a comprehensive understanding for clinical practice, and thus, to support the optimization and evaluation of treatment devices for finger joint, such as implant replacement.","3D motion analysis; Activities of daily living; Finger kinematics","en","book chapter","Springer Nature","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-05","","Human-Centered Design","Applied Ergonomics and Design","","",""
"uuid:806323be-e2aa-4bc6-86b1-ca2df873d75f","http://resolver.tudelft.nl/uuid:806323be-e2aa-4bc6-86b1-ca2df873d75f","Fast contrail estimation with OpenSky data","Sun, Junzi (TU Delft Control & Simulation); Roosenbrand, E.J. (TU Delft Control & Simulation)","","2024","Contrails, formed under specific atmospheric conditions, have a noteworthy role in heat-trapping within the atmosphere. This study bridges the gap between theoretical contrail formation models and real-world data by employing flight information from OpenSky and meteorological data from the European Centre for Medium-Range Weather Forecasts. We introduce a computationally efficient contrail estimation module, leveraging a client-server architecture that allows on-demand weather data interpolation via an API, significantly reducing computational load and enhancing performance locally. The study also benchmarks the entire pipeline, from data acquisition to contrail prediction, offering a robust tool for future air traffic studies requiring interpolated weather data.","Open-data; Emissions; Air Traffic","en","journal article","","","","","","","","","","","Control & Simulation","","",""
"uuid:f6290571-fabb-4857-910a-4fb4300b1c54","http://resolver.tudelft.nl/uuid:f6290571-fabb-4857-910a-4fb4300b1c54","Reviews and responses for Fast contrail estimation with OpenSky data","Sun, Junzi (TU Delft Control & Simulation); Roosenbrand, E.J. (TU Delft Control & Simulation)","Figuet, Benoit (editor); Dubot, Thomas (editor); Waltert, Manuel (editor); Olive, Xavier (editor)","2024","Contrails, formed under specific atmospheric conditions, have a noteworthy role in heat-trapping within the atmosphere. This study bridges the gap between theoretical contrail formation models and real-world data by employing flight information from OpenSky and meteorological data from the European Centre for Medium-Range Weather Forecasts. We introduce a computationally efficient contrail estimation module, leveraging a client-server architecture that allows on-demand weather data interpolation via an API, significantly reducing computational load and enhancing performance locally. The study also benchmarks the entire pipeline, from data acquisition to contrail prediction, offering a robust tool for future air traffic studies requiring interpolated weather data.","Open-data; Emissions; Air Traffic","en","contribution to periodical","","","","","","","","","","","Control & Simulation","","",""
"uuid:a024a3ff-7f37-4eb1-aaae-e71a3955ebc9","http://resolver.tudelft.nl/uuid:a024a3ff-7f37-4eb1-aaae-e71a3955ebc9","Compilation of an open-source traffic and CO2 emissions dataset for commercial aviation","Salgas, A. (Université de Toulouse); Sun, Junzi (TU Delft Control & Simulation); Delbecq, Scott (Université de Toulouse); Planès, Thomas (Université de Toulouse); Lafforgue, Gilles (Université de Toulouse)","","2024","The study of the environmental transition of the aviation sector calls for prospective traffic scenarios. Detailed traffic and emissions inventories are often needed to refine the available analyses and to enable the simulation of regionalised scenarios. In the past studies, these are generally based on commercial, proprietary traffic data, making their dissemination problematic and reducing the reproducibility of the science produced. Open-source alternatives do exist, but with limited geographical coverage. This paper presents a method to aggregate different sources of flight information, in order to obtain an open-source air traffic dataset for 2019. Then, missing flight information is identified and completed using an airline route database built from Wikipedia parsing and related socio-economic data. After that, several reference datasets are used to evaluate the accuracy of the extended open-source dataset. Despite varying accuracy for different routes, major traffic flows are reasonably well estimated at the country and continental levels. Finally, the CO2 emissions are obtained using an existing aircraft performance surrogate model, and the accuracies are examined compared to the results from previous studies.","Open-data; Emissions; Air Traffic","en","journal article","","","","","","","","","","","Control & Simulation","","",""
"uuid:2b0ec6e8-9134-483a-8c8f-4b6959591e94","http://resolver.tudelft.nl/uuid:2b0ec6e8-9134-483a-8c8f-4b6959591e94","Defining design orientation: A field-based discovery approach","Cankurtaran, P. (TU Delft Marketing and Consumer Research); Beverland, Michael B. (University of Sussex Business School); Farrelly, Francis J. (Royal Melbourne Institute of Technology University)","","2024","The value of design as a means of innovation has long been recognized. More recently, interest in how design can create value has moved from a functional to a strategic focus whereby the design concept defines the way in which the whole firm competes. This is known as “design orientation,” although research on the nature of this construct remains scarce. In this exploratory study to define and unpack the nature of design orientation we follow the same process as previous research on orientations, through extrapolation from the sustained behaviours at firms that use design to drive their strategy. Empirically, we ground our definition in insights from design experts and senior managers (n = 62) within a diverse sample of “design-oriented” firms (n = 26). We identify that design orientation consists of an overarching ethos defined by four core emphases (connective, empathetic, future, and aesthetic), reflected in and reinforced by eight behaviours (catalysing, integrating, perspective taking, marrying logics, disrupting, future-proofing, design language, and brand reinforcing). In so doing, we define the design orientation construct and identify the strategic investments firms can use to leverage it for competitive advantage. We provide an agenda for future research and explore managerial challenges associated with implementation.","Design orientation; Strategic design; Value creation; Innovation; Theory-building","en","journal article","","","","","","","","","","","Marketing and Consumer Research","","",""
"uuid:ac2616a6-2636-4834-b0e6-9e859a57795e","http://resolver.tudelft.nl/uuid:ac2616a6-2636-4834-b0e6-9e859a57795e","Corrosion classification through deep learning of electrochemical noise time-frequency transient information","Homborg, A.M. (TU Delft Team Arjan Mol; Netherlands Defence Academy); Mol, J.M.C. (TU Delft Team Arjan Mol); Tinga, Tiedo (Netherlands Defence Academy)","","2024","This paper for the first time treats the interpretation of electrochemical noise time-frequency spectra as an image classification problem. It investigates the application of a convolutional neural network (CNN) for deep learning image classification of electrochemical noise time-frequency transient information. Representative slices of these spectra were selected by our transient analysis technique and served as input images for the CNN. Corrosion data from two types of pitting corrosion processes serve as test cases: AISI304 and AA2024-T3 immersed in a 0.01M HCl and 0.1M NaCl solution between 0 and 1ks after immersion, respectively. Continuous wavelet transform (CWT) spectra and modulus maxima (MM) are used to train the CNN, either individually or in a combined form. The classification accuracy of the CNN trained with the combined dataset is 0.97 and with the two individual datasets 0.72 (only CWT spectrum) and 0.84 (only MM). The ability to additionally classify a more progressed form of pitting corrosion of AA2024-T3 between 9 and 10ks after immersion indicates that the proposed method is sufficiently robust using combined datasets with CWT spectra and MM. The pitting processes can effectively be detected and classified by the proposed method. The most important contribution of the present work is to introduce a novel procedure that decreases the classical need for large amounts of raw data for training and validation purposes, while still achieving a satisfactory classification robustness. A relatively small number of individual signals thereby generates a multitude of input images that still contain all relevant kinetic information about the underlying chemo-physical process.","Machine learning; Electrochemical noise transients; Continuous wavelet transform; Modulus maxima; Time-frequency images; Corrosion classification","en","journal article","","","","","","","","","","","Team Arjan Mol","","",""
"uuid:13431629-499d-4237-a99e-93f6aaf0c1b2","http://resolver.tudelft.nl/uuid:13431629-499d-4237-a99e-93f6aaf0c1b2","How Ready a Municipality is for Zero-Emission City Logistics? Development and Application of Maturity Model for Dutch Municipalities","Anand, N.R. (Rotterdam University of Applied Sciences); Motloung, T. (Breda University of Applied Sciences); Quak, H.J. (Breda University of Applied Sciences; TNO); van Duin, Ron (TU Delft Transport and Logistics; Rotterdam University of Applied Sciences)","","2024","The number of activities in city logistics is growing rapidly causing an increase in emissions, and a decline in accessibility and safety in cities. Therefore, the Dutch government has introduced GreenDeal Zero-emission city logistics. The goal of this deal is to have 30-40 of the biggest municipalities in the Netherlands have zero-emission city logistics in 2025. The goal for 2025 is clear, but it lacks a way for municipalities to see their progress and a way to find improvements in their city logistics. This research is focused on developing a maturity model as a tool to assess the maturity level of a municipality for its performance-related city logistics process management to achieve its aim of reaching zero emissions. The
City Logistics Maturity Model for Municipality (CL3M) requires a domain-specific, multidimensional model to assess city logistics from a municipal point of view. The model includes six levels (0-5) and a PCDA cycle is embedded throughout the levels. The model is populated through three focus fields (Technical, Social and Corporate, and Policy), branching out into six areas of development: Information and communication technology, urban logistics planning, Stakeholder communication, Public-Private Partnerships, Subsidization and incentivization, and Regulations. The CL3M model was tested for three municipalities, namely, the municipality of Deventer, Zwolle, and Nijmegen. The assessment pointed out that CL3M is yet in its juvenile stage and with further development, the model can reach its full potential in usefulness, reliability, and adaptation","City logistics; Maturity model; CO2 Emissions; zero emission; Climate Agreement","en","conference paper","","","","","","","","","","","Transport and Logistics","","",""
"uuid:06b36cb6-1728-449a-bb66-422be9095e57","http://resolver.tudelft.nl/uuid:06b36cb6-1728-449a-bb66-422be9095e57","Can an energy only market enable resource adequacy in a decarbonized power system?: A co-simulation with two agent-based-models","Sanchez Jimenez, I.J. (TU Delft Energie and Industrie); Ribo-Perez, D.G. (TU Delft Energie and Industrie; Universitat Politécnica de Valencia); Cvetkovic, M. (TU Delft Intelligent Electrical Power Grids); Kochems, J. (German Aerospace Center); Schimeczek, C. (German Aerospace Center); De Vries, Laurens (TU Delft Energie and Industrie)","","2024","Future power systems, in which generation will come almost entirely from variable Renewable Energy Sources (vRES), will be characterized by weather-driven supply and flexible demand. In a simulation of the future Dutch power system, we analyze whether there are sufficient incentives for market-driven investors to provide a sufficient level of security of supply, considering the profit-seeking and myopic behavior of investors. We co-simulate two agent-based models (ABM), one for generation expansion and one for the operational time scale. The results suggest that in a system with a high share of vRES and flexibility, prices will be set predominantly by the demand’s willingness to pay, particularly by the opportunity cost of flexible hydrogen electrolyzers. The demand for electric heating could double the price of electricity in winter, compared to summer, and in years with low vRES could cause shortages. Simulations with stochastic weather profiles increase the year-to-year variability of cost recovery by more than threefold and the year-to-year price variability by more than tenfold compared to a scenario with no weather uncertainty. Dispatchable technologies have the most volatile annual returns due to high scarcity rents during years of low vRES production and diminished returns during years with high vRES production. We conclude that in a highly renewable EOM, investors would not have sufficient incentives to ensure the reliability of the system. If they invested in such a way to ensure that demand could be met in a year with the lowest vRES yield, they would not recover their fixed costs in the majority of years.","Agent-based model; High share of renewable energies; Flexibility; Co-simulation","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:083a7ad7-5f15-4a68-bf50-5cd1017ef780","http://resolver.tudelft.nl/uuid:083a7ad7-5f15-4a68-bf50-5cd1017ef780","Data analytics in managing projects","Papadonikolaki, E. (TU Delft Integral Design & Management); Galera-Zarco, Carlos (University College London (UCL))","Huemann, Martina (editor); Turner, Rodney (editor)","2024","In today’s society, project work gains traction across many industries. As projects are characterised by novelty and uncertainty, emerging digital technologies promise solutions that improve performance and help deliver full benefits. Amidst this digitisation, digital technologies such as data analytics and Artificial Intelligence (AI) streamline the large amount of data generated. However, this critical information is only partially leveraged during and after projects to date. Project data are generated, collected, and analysed across all stages of project management and delivery. Eleni Papadonikolaki and Carlos Galera-Zarco conceptualise the relation between projects, information, and data, and discuss key application areas of data analytics in projects, for instance in scheduling and costing. Next, they present the state-of-the-art applications, means, and tools of data analytics in key areas of project management. Finally, they set out challenges and future opportunities around project data analytics especially with regard to leadership, teamwork, and talent management.","","en","book chapter","Routledge - Taylor & Francis Group","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-28","","","Integral Design & Management","","",""
"uuid:f2294efd-4de1-4df0-8573-881ebaee4fa1","http://resolver.tudelft.nl/uuid:f2294efd-4de1-4df0-8573-881ebaee4fa1","Microsegregation Influence on Austenite Formation from Ferrite and Cementite in Fe–C–Mn–Si and Fe–C–Si Steels","Krugla, M. (TU Delft Team Erik Offerman; Tata Steel); Offerman, S.E. (TU Delft Team Erik Offerman); Sietsma, J. (TU Delft Team Joris Dik); Hanlon, Dave N. (Tata Steel)","","2024","The production reality of sheet steels from casting to the end product is such that in the cases of ultra- and advanced high-strength steels, we have to deal with the segregation of elements on macro- and microlevels. Both can have a significant impact on the microstructure formation and resulting properties. There are several production stages where it can influence the transformations, i.e., casting, hot rolling process and annealing after cold rolling. In the present work, we focus on the latter, and more specifically, the transformation from ferrite–cementite to austenite, especially the nucleation process, in cold-rolled material. We vary the levels of two substitutional elements, Mn and Si, and then look in detail at the microsegregation and nucleation processes. The classical nucleation theory is used, and both the chemical driving force and strain energy are calculated for various scenarios. In the case of a high Mn and high Si concentration, the nucleation can thus be explained. In the cases of high Mn and low Si concentrations as well as low Mn alloys, more research is needed on the nuclei shapes and strain energy.","nucleation; microsegregation; advanced high-strength steels; driving force; Strain Energy Release","en","journal article","","","","","","","","","","","Team Erik Offerman","","",""
"uuid:14d82dc4-eaa0-44af-b5b8-0459cb7dbd54","http://resolver.tudelft.nl/uuid:14d82dc4-eaa0-44af-b5b8-0459cb7dbd54","Can designers take the driver’s seat? A new human-centered process to design with data and machine learning","Colombo, S. (TU Delft Human-Centred Artificial Intelligence); Costa, Camilla (Politecnico di Milano)","","2024","Machine Learning (ML) is increasingly becoming a crucial asset across diverse industries. However, designers lack human-centered processes to envision and develop innovative solutions enabled by ML. By engaging in a Research-through-Design activity, we outline a new design process to generate human-centered adaptive systems enabled by data and ML. We describe and discuss the possibilities and limits of designing with ML, the need to concurrently address user experience and ML aspects, and the implications of their mutual influence. We argue that designers can envision and design human-centered ML-enabled systems if they acquire fundamental ML knowledge, although certain tasks necessitate close collaboration with ML experts. We discuss how uncertainty and risk of failure characterize the outlined process and may limit its applicability. The proposed process serves as a foundational framework for future research in human-centered design innovation through data and ML.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-21","","","Human-Centred Artificial Intelligence","","",""
"uuid:5398d36a-a785-4f27-991d-aaffb23be2e8","http://resolver.tudelft.nl/uuid:5398d36a-a785-4f27-991d-aaffb23be2e8","Adaptive Differentially Quantized Subspace Perturbation (ADQSP): A Unified Framework for Privacy-Preserving Distributed Average Consensus","Li, Qiongxiu (Tsinghua University); Gundersen, Jaron Skovsted (Aalborg University); Lopuhaa-Zwakenberg, Milan (University of Twente); Heusdens, R. (TU Delft Signal Processing Systems; Netherlands Defence Academy)","","2024","Privacy-preserving distributed average consensus has received significant attention recently due to its wide applicability. Based on the achieved performances, existing approaches can be broadly classified into perfect accuracy-prioritized approaches such as secure multiparty computation (SMPC), and worst-case privacy-prioritized approaches such as differential privacy (DP). Methods of the first class achieve perfect output accuracy but reveal some private information, while methods from the second class provide privacy against the strongest adversary at the cost of a loss of accuracy. In this paper, we propose a general approach named adaptive differentially quantized subspace perturbation (ADQSP) which combines quantization schemes with so-called subspace perturbation. Although not relying on cryptographic primitives, the proposed approach enjoys the benefits of both accuracy-prioritized and privacy-prioritized methods and is able to unify them. More specifically, we show that by varying a single quantization parameter the proposed method can vary between SMPC-type performances and DP-type performances. Our results show the potential of exploiting traditional distributed signal processing tools for providing cryptographic guarantees. In addition to a comprehensive theoretical analysis, numerical validations are conducted to substantiate our results.","consensus; data aggregation; decentralized networks; differential privacy; quantization; Secure multiparty computation; subspace perturbation","en","journal article","","","","","","","","2024-07-22","","","Signal Processing Systems","","",""
"uuid:094250fb-166d-4fe7-891f-5d313229c515","http://resolver.tudelft.nl/uuid:094250fb-166d-4fe7-891f-5d313229c515","Capturing Electricity Market Dynamics in Strategic Market Participation Using Neural Network Constrained Optimization","Dolanyi, Mihaly (Katholieke Universiteit Leuven); Bruninx, K. (TU Delft Energie and Industrie; Katholieke Universiteit Leuven); Toubeau, Jean Francois (Université de Mons); Delarue, Erik (Katholieke Universiteit Leuven)","","2024","In competitive electricity markets, the optimal bid or offer problem of a strategic agent is commonly formulated as a bi-level program and solved as a mathematical program with equilibrium constraints (MPEC). If the lower-level (LL) part of the problem can be well approximated as a convex problem, this approach leads to a global optimum. However, electricity markets are governed by non-convex (partially known) constraints and reward functions of the participating agents. In this paper, an alternative data-driven paradigm, labeled as a mathematical program with neural network constraint (MPNNC), is developed. The method uses a neural network to represent the mapping between the upper-level (agent) decisions and the lower-level (market) outcomes, i.e., it replaces the lower-level problem with a surrogate model. In the presented case studies, the proposed model is used to find the optimal load shedding strategy of a strategic load-serving entity. First, the MPNNC performance is compared to the MPEC approach, both in convex and non-convex environments, showing that the proposed MPNNC achieves similar performance to an ideal MPEC that has perfect knowledge of the simulated market environment. Then, aggregated supply curves from the Belgian spot exchange are used to assess the potential gains of using the developed model in real-life applications.","electricity markets; mathematical program with neural network constraint; Strategic bidding","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-27","","","Energie and Industrie","","",""
"uuid:187343ad-a455-475c-89a5-868966358afb","http://resolver.tudelft.nl/uuid:187343ad-a455-475c-89a5-868966358afb","Estimating bridge criticality due to extreme traffic loads in highway networks","Mendoza Lugo, M.A. (TU Delft Hydraulic Structures and Flood Risk); Nogal Macho, M. (TU Delft Integral Design & Management); Morales Napoles, O. (TU Delft Hydraulic Structures and Flood Risk)","","2024","Around the world, an increasing amount of bridge infrastructure is ageing. The resources involved in the reassessment of existing assets often exceed available resources and many bridges lack a minimum structural assessment. Therefore, there is a need for comprehensive and quantitative approaches to assess all the assets in the bridge network to reduce the risk of collapsing, damage to infrastructure, and economic losses. This paper proposes a methodology to quantify the structural criticality of bridges at a network level. To accomplish this, long-run site-specific simulations are conducted using Bayesian Networks and bivariate copulas, utilizing recorded traffic data obtained from permanent counting stations. To enhance the dataset, information from Weigh-in-Motion systems from different regions was integrated through a matching process. Subsequently, the structural response resulting from the simulated traffic is assessed, and the extreme values of the traffic load effects are obtained for selected return periods. Site-specific bridge criticality as a performance indicator for traffic load effects is derived by comparing the extreme load effects with the design load effects. The outcomes are mapped to facilitate visualization employing an open-source geographic information system application. To illustrate the application of the methodology, a total of 576 bridges within a national highway network are investigated, and a comparison with a popular simplified method is shown. The methodology herein presented can be used to assist in assessing the condition of a bridge network and prioritizing maintenance and repair activities by identifying potential bridges subjected to major load stress.","Bayesian Network; Copulas; Extreme value; Bridge network; Maps; Traffic load effects; Bridge criticality","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:00b74fa5-8fef-4514-a21f-877159d58c88","http://resolver.tudelft.nl/uuid:00b74fa5-8fef-4514-a21f-877159d58c88","Intelligent Anomaly Detection for Lane Rendering Using Transformer with Self-Supervised Pre-Training and Customized Fine-Tuning","Dong, Y. (TU Delft Transport and Planning); Lu, Xingmin (North China University of Technology); Li, Ruohan (Villanova University); Song, Wei (North China University of Technology); van Arem, B. (TU Delft Transport and Planning); Farah, H. (TU Delft Transport and Planning)","","2024","The burgeoning navigation services using digital maps provide great convenience to drivers. However, there are sometimes anomalies in the lane rendering map images, which might mislead human drivers and result in unsafe driving. To accurately and effectively detect the anomalies, this paper transforms lane rendering image anomaly detection into a classification problem and proposes a four-phase pipeline consisting of data pre-processing, self-supervised pre-training with the masked image modeling (MiM) method, customized fine-tuning using cross-entropy loss with label smoothing, and post-processing to tackle it using state-of-the-art deep learning techniques, especially the Transformer models. Various experiments verify the effectiveness of the proposed pipeline. The proposed pipeline can deliver superior lane rendering image anomaly detection performance, and especially, the self-supervised pre-training with MiM can greatly improve the detection accuracy while significantly reducing the total training time, e.g, Swin Transformer with Uniform Masking as self-supervised pretraining (Swin-Trans-UM) obtained better accuracy at 94.77% and better Area Under The Curve (AUC) at 0.9743 compared with the pure Swin Transformer without pre-training (Swin-Trans) whose accuracy is 94.01% AUC is 0.9498, and the fine-tuning epochs reduced to 41 from original 280. Ablation study further regarding techniques to alleviate the data imbalance between normal and abnormal instances further enhances the model performance.","Anomaly Detection; Lane rendering image; Transformer; Self-supervised learning; Image classification","en","poster","","","","","","","","","","","Transport and Planning","","",""
"uuid:0ca8e7f6-6d62-4425-ae47-830d1024ba39","http://resolver.tudelft.nl/uuid:0ca8e7f6-6d62-4425-ae47-830d1024ba39","Blade Element Theory Model for UAV Blade Damage Simulation","de Alvear Cardenas, J.I. (San José State University); de Visser, C.C. (TU Delft Control & Simulation)","","2024","From fault-tolerant control to failure detection, blade damage simulation is integral for developing and testing failure-resilient modern unmanned aerial vehicles. Existing approaches assume partial loss of rotor effectiveness or reduce the problem to centrifugal forces resulting from the shift in the propeller centre of gravity. In this study, a white-box blade damage model based on Blade Element Theory is proposed, integrating both mass and aerodynamic effects of blade damage. The model serves as plug-in to the nominal system model, enables the simulation of any degree of blade damage and does not require costly experimental data from failure cases. A complementary methodology for the identification of the airfoil lift and drag coefficients is also presented. Both contributions were demonstrated with the Bebop 2 drone platform and validated with static test stand wrench measurements obtained at 3 levels of blade damage (0%, 10%, 25%) in a dedicated wind tunnel experimental campaign with velocities up to 12 m/s. Results indicate high accuracy in simulating a healthy propeller. In the presence of blade damage, the model exhibits a relative error between 5% and 24% at high propeller rotational speeds and between 15% and 75% at low propeller rotational speeds.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Control & Simulation","","",""
"uuid:19af5ad2-e69d-435e-9539-c89dd885a27f","http://resolver.tudelft.nl/uuid:19af5ad2-e69d-435e-9539-c89dd885a27f","Unreal Success: Vision-Based UAV Fault Detection and Diagnosis Framework","de Alvear Cardenas, J.I. (San José State University); de Visser, C.C. (TU Delft Control & Simulation)","","2024","Online fault detection and diagnosis (FDD) enables Unmanned Aerial Vehicles (UAVs) to take informed decisions upon actuator failure during flight, adapting their control strategy or deploying emergency systems. Despite the camera being a ubiquitous sensor on-board of most commercial UAVs, it has not been used within FDD systems before, mainly due to the nonexistence of UAV multi-sensor datasets that include actuator failure scenarios. This paper presents a knowledge-based FDD framework based on a lightweight LSTM network and a single layer neural network classifier that fuses camera and Inertial Measurement Unit (IMU) information. Camera data are pre-processed by first computing its optical flow with RAFT-S, a state-of-the-art deep learning model, and then extracting features with the backbone of MobileNetV3-S. Short-Time Fourier Transform is applied on the IMU data for obtaining their time-frequency information. For training and assessing the proposed framework, UUFOSim was developed: an Unreal Engine-based simulator built on AirSim that allows the collection of high-fidelity photo-realistic camera and sensor information, and the injection of actuator failures during flight. Data were collected in simulation for the Bebop 2 UAV with 16 failure cases. Results demonstrate the added value of the camera and the complementary nature of both sensors with failure detection and diagnosis accuracies of 99.98% and 98.86%, respectively.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Control & Simulation","","",""
"uuid:1101dd16-9bfc-4cac-a5c6-0d29d03da42f","http://resolver.tudelft.nl/uuid:1101dd16-9bfc-4cac-a5c6-0d29d03da42f","A hybrid decision-making framework for a supplier selection problem based on lean, agile, resilience, and green criteria: a case study of a pharmaceutical industry","Sheykhzadeh, Morteza (University of Tehran); Ghasemi, Rohollah (University of Tehran); Vandchali, Hadi Rezaei (University of Tasmania); Sepehri, A. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Torabi, Seyed Ali (University of Tehran)","","2024","Due to the outbreak of COVID-19 around the globe in the last few years, the need for pharmaceutical supply chains is felt more than before. However, increasing uncertainties along with unpredictable demand for products led to disruptions in supply chains when receiving requests from retailers. These disruptions not only affected the economic aspect of supply chains but also caused shortages in hospitals and medical centers. Therefore, it has become significant for companies to select their suppliers to avoid disruptions in the case of the severity of infections. To address this issue in practice, this paper has been conducted based on a case study to address the role of lean, agile, resilience, and green (LARG) criteria in selecting the supplier in a pharmaceutical supply chain and compare the results obtained before and after the prevalence of COVID-19. The main purpose of this study is to determine and evaluate different indicators within the LARG concept to avoid disruptions when selecting suppliers. Besides, the significance of these criteria before and after the pandemic condition is addressed. Due to addressing multiple aspects of the problem, a hybrid fuzzy multi-attribute decision-making (MADM) approach is adopted for this elaboration when the four LARG criteria are integrated with eighteen supplier selection sub-criteria. To calculate the impact of each criterion (or sub-criteria), a fuzzy best–worst method (BWM) along with an additive ratio assessment (ARAS) is employed to propose a supplier ranking for a distributor of a pharmaceutical supply chain. The developed model is novel as LARG criteria in the context of supplier selection have not been studied to address the disruptions in the pharmaceutical supply chain. This is significant because it gives insight to both retailers and suppliers to emphasize the correct criteria, especially in the pandemic or related disrupting conditions. The results demonstrated that quality, collaboration, safety stock, and environmental criteria weigh the highest before the pandemic, while just-in-time delivery, lead time, safety stock, and environmental criteria weigh the highest after the pandemic. This study demonstrates that developing a supplier selection approach that meets the demand in a short time and recommends suppliers to hold surplus inventory helps the healthcare systems better respond to the market needs.","Fuzzy multi-attribute decision-making; LARG supply chain; Pharmaceutical supply chains; Supplier selection","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-02","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:e316ce2d-d063-4e7b-a686-0c74d3b4905a","http://resolver.tudelft.nl/uuid:e316ce2d-d063-4e7b-a686-0c74d3b4905a","Multi-Sensor Seismic Processing Approach using Geophones and HWC DAS in the Monitoring of CO2 Storage at the Hellisheiði Geothermal Field in Iceland","Bellezza, Cinzia (OGS-National Institute of Oceanography and Applied Geophysics–); Barison, Erika (OGS-National Institute of Oceanography and Applied Geophysics–); Farina, Biancamaria (OGS-National Institute of Oceanography and Applied Geophysics–); Poletto, Flavio (OGS-National Institute of Oceanography and Applied Geophysics–); Meneghini, Fabio (OGS-National Institute of Oceanography and Applied Geophysics–); Böhm, Gualtiero (OGS-National Institute of Oceanography and Applied Geophysics–); Draganov, D.S. (TU Delft Applied Geophysics and Petrophysics); Janssen, M.T.G. (TU Delft Applied Geophysics and Petrophysics); van Otten, Gijs (Seismic Mechatronics BV)","","2024","Geothermal power production may result in significant CO2 emissions as part of the produced steam. CO2 capture, utilisation, subsurface storage (CCUS) and developments to exploit geothermal resources are focal points for future clean and renewable energy strategies. The Synergetic Utilisation of CO2 Storage Coupled with Geothermal Energy Deployment (SUCCEED) project aims to demonstrate the feasibility of using produced CO2 for re-injection in the geothermal field to improve geothermal performance, while also storing the CO2 as an action for climate change mitigation. Our study has the aim to develop innovative reservoir-monitoring technologies via active-source seismic data acquisition using a novel electric seismic vibrator source and permanently installed helically wound cable (HWC) fibre-optic distributed acoustic sensing (DAS) system. Implemented together with auxiliary multi-component (3C and 2C) geophone receiver arrays, this approach gave us the opportunity to compare and cross-validate the results using wavefields from different acquisition systems. We present the results of the baseline survey of a time-lapse monitoring project at the Hellisheiði geothermal field in Iceland. We perform tomographic inversion and multichannel seismic processing to investigate both the shallower and the deeper basaltic rocks targets. The wavefield analysis is supported by seismic modelling. The HWC DAS and the geophone-stacked sections show good consistency, highlighting the same reflection zones. The comparison of the new DAS technology with the well-known standard geophone acquisition proves the effectiveness and reliability of using broadside sensitivity HWC DAS in surface monitoring applications.","CO2 injection monitoring; geothermal reservoir; CCUS; surface seismic processing; distributed acoustic sensing (DAS); geophones","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:4dc3ba97-ae9c-40eb-bf7e-c49bcddba7d9","http://resolver.tudelft.nl/uuid:4dc3ba97-ae9c-40eb-bf7e-c49bcddba7d9","Digital government and the circular economy transition: An analytical framework and a research agenda","Medaglia, Rony (Copenhagen Business School); Rukanova, B.D. (TU Delft Innovation Affairs); Zhang, Ziyan (Sun Yat-sen University)","","2024","The transition from a linear economy towards a circular economy (CE), based on reusing, repairing, refurbishing, and recycling existing materials and products, is one of the key priorities in pursuing Sustainable Development Goals (SDGs), where governments play a fundamental role, with the support of digital technologies.
Despite the increasing global policy focus on CE, research on the role of digital government in initiating, implementing, and consolidating a transition towards a circular economy is surprisingly scarce and fragmented, and a systematic effort in digital government research is yet to emerge.
To tackle this issue, this article sets out to answer the research question: what is the role of digital government in the transition towards a circular economy? Driven by this research question, we conduct a review on 88 empirical studies in the Information Systems (IS) and digital government fields and discuss existing research foci and gaps in relation to the types of digital technologies used, the types of stakeholders involved, the stages of the product life cycle, and the type of resources that governments draw on to advance the circular economy transition. In addition, we identify two types of transition styles, based on an analysis of the types of roles taken by the government in two cases of transition towards a circular economy.
Based on these findings, we provide two contributions to establishing a new line of research in digital government and the circular economy: an analytical framework, including a static view, a longitudinal view, and a transition style view of the role of digital government in the circular economy transition; and a research agenda that builds on our framework, to guide future research on the role of digital government in the circular economy transition.","Digital government; Circular economy; Sustainability","en","journal article","","","","","","","","","","","Innovation Affairs","","",""
"uuid:9dd31e25-1136-4d3b-bcdb-0e3ef4104903","http://resolver.tudelft.nl/uuid:9dd31e25-1136-4d3b-bcdb-0e3ef4104903","The Push Forward in Rehabilitation: Validation of a Machine Learning Method for Detection of Wheelchair Propulsion Type","van der Slikke, R.M.A. (TU Delft Biomechatronics & Human-Machine Control; The Hague University of Applied Sciences); de Leeuw, Arie-Willem (The Hague University of Applied Sciences); de Rooij, Aleid (Leiden University Medical Center; Basalt Revalidatie); Berger, M.A.M. (The Hague University of Applied Sciences; Basalt Revalidatie)","","2024","Within rehabilitation, there is a great need for a simple method to monitor wheelchair use, especially whether it is active or passive. For this purpose, an existing measurement technique was extended with a method for detecting self- or attendant-pushed wheelchair propulsion. The aim of this study was to validate this new detection method by comparison with manual annotation of wheelchair use. Twenty-four amputation and stroke patients completed a semi-structured course of active and passive wheelchair use. Based on a machine learning approach, a method was developed that detected the type of movement. The machine learning method was trained based on the data of a single-wheel sensor as well as a setup using an additional sensor on the frame. The method showed high accuracy (F1 = 0.886, frame and wheel sensor) even if only a single wheel sensor was used (F1 = 0.827). The developed and validated measurement method is ideally suited to easily determine wheelchair use and the corresponding activity level of patients in rehabilitation.","rehabilitation; inertial sensor; wheelchair activity","en","journal article","","","","","","","","","","","Biomechatronics & Human-Machine Control","","",""
"uuid:35663783-562d-4a7e-82d9-3d0d66123c8a","http://resolver.tudelft.nl/uuid:35663783-562d-4a7e-82d9-3d0d66123c8a","How Trees Shape Urban Spaces: Multiplicity and Differentiation of the Urban Forest Viewed from a Visual-Spatial Perspective","de Wit, S.I. (TU Delft Landscape Architecture); van der Velde, J.R.T. (TU Delft Landscape Architecture)","","2024","Background: The field of urban forestry encompasses many dimensions, of which that of visual-spatial perception, addressing the spatial relationship between city and trees, has received little attention. Analyzing the urban forest from a visual-spatial perspective is needed to understand relationships between different components as well as site-specific qualities. Methods: Tree configurations describe the relationship between form and space, determined by the relative disposition of the trees which result from an interaction between design and the development over time. Based on field observations, with the city of Delft in the Netherlands as a case study, 35 generic tree configuration types have been defined. With this “vocabulary,” specific tree configurations and their relations are researched, describing the urban forest from an eyelevel perspective as an essential level on which the spatiality of the urban forest can be understood. Results: Unraveling the urban forest components by comparing two emblematic ensembles of tree configurations allows an understanding of their heterogeneity as well as their coherence and dynamics. Conclusions: The relationship of the tree vocabulary with the specific location exposes their role as an ordering structure and a carrier of the identity of Delft, and their differentiation and site-specific qualities, revealing a composition of wooded areas each with their own characteristics, shows both urban and forested areas as equivalent components of an urban forest mosaic. This differentiation can be used as a tool for strengthening relations between the different components as well as diversity and heterogeneity in urban forests.","site specificity; tree configurations; Tree architecture; tree vocabulary; visual-spatial characteristics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-01","","","Landscape Architecture","","",""
"uuid:b9c15cb9-5740-404c-abbf-ffafd2a71bd7","http://resolver.tudelft.nl/uuid:b9c15cb9-5740-404c-abbf-ffafd2a71bd7","Do wool carpets ‘clean’ the air or not? A study on the sorption effects of wool carpets by sensory evaluation","Noorian Najafabadi, S.A. (TU Delft Environmental & Climate Design); Ding, Er (TU Delft Environmental & Climate Design); Hobeika, N. (TU Delft Urban Data Science); Bluyssen, P.M. (TU Delft Environmental & Climate Design)","","2024","Indoor air quality (IAQ) is an important aspect of maintaining human health and well-being, particularly since people spend most of their time indoors. Carpets, with their large surface area and dense fibre piles, have the potential to significantly impact IAQ by emitting and absorbing volatile organic compounds (VOC) from building materials and human activities. The cleaning effect of wool carpets regarding the sorption of odours from two sources of pollution: hardboard and sweaty underwear (as a proxy for bio-effluents), was investigated with an untrained panel of subjects assessing the odour intensity and the acceptability. Tests were performed in three different test environments, including a sniffing table, CLIMPAQs, and full-scale test chambers. The outcome showed that wool carpets can potentially clean the air of odours in small-scale environments, where the wool carpet covers the floor and walls of the test environment, and the odour sources are in contact with the wool carpet. However, the results were less conclusive in on scale scenarios where wool carpets only covered the floor. Overall, wool carpets have the potential to ad(b)sorb odorous emissions, but only when these emissions are near the wool carpet, and thus can have the opportunity to be ad(b)sorbed.","Sensory evaluation; Indoor air quality; Wool carpets; Ad(b)sorption; Indoor air pollution","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:f58bf308-39b9-4053-bab3-6f0bc5a44cdb","http://resolver.tudelft.nl/uuid:f58bf308-39b9-4053-bab3-6f0bc5a44cdb","Linking residential mobility with daily mobility: A three-wave cross-lagged panel analysis of travel mode choices and preferences pre–post residential relocation in the Netherlands","Tao, Y. (TU Delft Urban Studies)","","2024","The causal impact of the built environment on travel behaviours is a subject of debate. This debate especially concerns the independent effect of the built environment on the observed travel patterns after taking into account residential self-selection arising from pre-existing travel-related attitude. This study argues that travel attitude varies over time, and thus, is also reshaped by residential built environment and interrelated with residents? travel behaviours. Focusing on the event of residential relocation in the Netherlands, this study longitudinally investigated the interrelations between travel mode choices and preferences before, immediately after and a year after the relocation. Results from the random-intercept cross-lagged panel models substantiated the residential self-selection based on the pre-relocation preferences for motorised means of transport, including cars and public transport. Moreover, travel mode preferences varied to a greater extent than travel mode use pre?post relocation, and especially, frequent use of public transport or bicycles stimulated by the new place of residence had a one-year lagged effect on developing the mode preference. Therefore, the structural role of residential built environment manifests as (re)shaping travel mode choices as well as mode-specific preferences in the process of residential relocation.","longitudinal design; neighbourhood effects; Netherlands; residential self-selection; travel behavior","en","journal article","","","","","","","","","","","Urban Studies","","",""
"uuid:91c087a3-6d22-4b55-b0d9-884b2747a7bc","http://resolver.tudelft.nl/uuid:91c087a3-6d22-4b55-b0d9-884b2747a7bc","Inkjet printing P(VDF-TrFE-CTFE) actuators for large bending strains","Sekar, S.A. (Student TU Delft); Hunt, A. (TU Delft Micro and Nano Engineering)","","2024","Additive manufacturing of sensors and actuators together with structural materials and electronics will make it possible to fabricate innovative system designs that are overly laborious to realise with conventional methods. While printing of the structural materials and electronics are advancing fast, the additive manufacturing methods for actuators and sensors are in an earlier stage of development. This research will develop a manufacturing process for entirely inkjet printed electroactive polymer (EAP) actuators basing on the P(VDF-TrFE-CTFE) relaxor ferroelectric polymer and Ag electrodes. The process consists of (1) printing an Ag layer on a polyethylene terephthalate (PET) substrate for the bottom electrode; (2) formulating, printing and annealing a P(VDF-TrFE-CTFE) ink for the EAP layer; and (3) printing and sintering an Ag layer on the plasma-treated EAP surface to form the top electrode. Two actuator variations, addressed as DMC and KM512, are manufactured and characterised by their: (a) response to quasi-static excitation (1 Hz sine wave); (b) hysteresis behaviour; (c) actuation amplitude variation with the input voltage; and (d) frequency response. The 18 mm long actuators showed 91.4 µm (DMC, 200 V p p ) and 224 µm (KM512, 275 V p p ) deflections in response to 1 Hz sinusoidal excitation, and 1.10 mm (DMC, 113 Hz, 200 V p p ) and 1.72 mm (KM512, 114 Hz, 200 V p p ) deflections in resonant operation. It is 55% more quasi-static strain and 470% more resonant strain than in earlier fully inkjet-printed polyvinylidene fluoride (PVDF) -based actuators, and comparable to similar partially inkjet-printed actuators. This is the first time that inkjet printing of all three layers of a relaxor ferroelectric actuator have been achieved.","actuator; inkjet printing; electroactive polymer; ink formulation; piezoelectric; ferroelectric; P(VDF-TrFE-CTFE)","en","journal article","","","","","","","","","","","Micro and Nano Engineering","","",""
"uuid:e5a9fa2b-2f10-4393-a985-f1f1f2d8d154","http://resolver.tudelft.nl/uuid:e5a9fa2b-2f10-4393-a985-f1f1f2d8d154","Correlated Sparse Bayesian Learning for Recovery of Block Sparse Signals with Unknown Borders","Doğan, D. (TU Delft Signal Processing Systems); Leus, G.J.T. (TU Delft Signal Processing Systems)","","2024","We consider the problem of recovering complex-valued block sparse signals with unknown borders. Such signals arise naturally in numerous applications. Several algorithms have been developed to solve the problem of unknown block partitions. In pattern-coupled sparse Bayesian learning (PCSBL), each coefficient involves its own hyperparameter and those of its immediate neighbors to exploit the block sparsity. Extended block sparse Bayesian learning (EBSBL) assumes the block sparse signal consists of correlated and overlapping blocks to enforce block correlations. We propose a simpler alternative to EBSBL and reveal the underlying relationship between the proposed method and a particular case of EBSBL. The proposed algorithm uses the fact that immediate neighboring sparse coefficients are correlated. The proposed model is similar to classical sparse Bayesian learning (SBL). However, unlike the diagonal correlation matrix in conventional SBL, the unknown correlation matrix has a tridiagonal structure to capture the correlation with neighbors. Due to the entanglement of the elements in the inverse tridiagonal matrix, instead of a direct closed-form solution, an approximate solution is proposed. The alternative algorithm avoids the high dictionary coherence in EBSBL, reduces the unknowns of EBSBL, and is computationally more efficient. The sparse reconstruction performance of the algorithm is evaluated with both correlated and uncorrelated block sparse coefficients. Simulation results demonstrate that the proposed algorithm outperforms PCSBL and correlation-based methods such as EBSBL in terms of reconstruction quality. The numerical results also show that the proposed correlated SBL algorithm can deal with isolated zeros and nonzeros as well as block sparse patterns.","block sparse signals; correlated sparse Bayesian learning; expectation-maximization (EM) method; compressive sensing","en","journal article","","","","","","","","","","","Signal Processing Systems","","",""
"uuid:5e3140a9-f6e0-4247-b706-9442fcde54ff","http://resolver.tudelft.nl/uuid:5e3140a9-f6e0-4247-b706-9442fcde54ff","Spatiotemporal operando UV–vis spectroscopy: Development and mechanistic alternation of CO oxidation on Pt/Al2O3 on the reactor scale","van Beek, L.E. (TU Delft ChemE/Catalysis Engineering; Université Grenoble Alpes); Jain, D. (TU Delft ChemE/Catalysis Engineering); Gholkar, P.V. (TU Delft ChemE/Catalysis Engineering); Eldridge, T.J. (TU Delft ChemE/Catalysis Engineering); Nguyen, H.P. (Toyota Motor Europe); Muramoto, Kei (Toyota Motor Europe); Urakawa, A. (TU Delft ChemE/Catalysis Engineering)","","2024","Operando methodologies are widely used in heterogenous catalysis to understand unique state of catalyst materials emerging under specific reaction conditions and to establish catalyst structure-activity relationships. Recent studies highlight the importance of combining multiple operando techniques (multimodal approach) to gain complementary information as well as looking into chemical and material gradients and spatial variations on the reactor scale. In this work, we developed an operando UV–vis diffuse reflectance spectroscopy (DRS) setup compatible with a common fixed-bed tubular reactor. The design is based on optical calculations, validation experiments and signals considerations. A spatial resolution of 1 mm along the axial direction of the reactor was successfully demonstrated and combined with a time resolution of seconds with good signal to noise. CO oxidation over Pt/Al2O3 was performed as a proof of principle experiment demonstrating the capabilities of the new setup. The information gained by the space-resolved operando UV–vis DRS was combined with other space-resolved operando studies such as diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), gas sampling and temperature profiling. The study shows that the nature of active sites (Pt redox state) and thus the reaction mechanism alter with reaction temperature and also in space. Spatiotemporal UV–vis DRS is also demonstrated, showing the capability for transient studies with space-resolution.","CO oxidation; Diffuse reflection; operando; Pt/AlO; Space- and time-resolution; UV–vis","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:94b2a5b9-d869-4415-a713-ec39427809f0","http://resolver.tudelft.nl/uuid:94b2a5b9-d869-4415-a713-ec39427809f0","Ground-Based Soil Moisture Retrieval Using the Correlation Between Dual-Polarization GNSS-R Interference Patterns","El Hajj, Marcel M. (King Abdullah University of Science and Technology); Steele-Dunne, S.C. (TU Delft Mathematical Geodesy and Positioning); Almashharawi, Samer K. (King Abdullah University of Science and Technology); Tian, X. (TU Delft Geoscience and Remote Sensing; Wageningen University & Research); Johansen, Kasper (King Abdullah University of Science and Technology); Camargo, Omar A.Lopez (King Abdullah University of Science and Technology); Amezaga-Sarries, Adria (Microwave Sensors and Electronics Sl); Mas-Vinolas, Andreu (Microwave Sensors and Electronics Sl); McCabe, Matthew F. (King Abdullah University of Science and Technology)","","2024","Soil moisture (SM) is an important state variable in land surface models. Here, we investigate the potential of a ground-based global navigation satellite system receiver with two linearly polarized antennas that measure the interference power (IP) of direct and reflected signals in horizontal polarization (H-pol) and vertical polarization (V-pol) to estimate SM. The coefficient of determination between the IP waveforms at H-pol and V-pol ( $\boldsymbol {R}_{ \boldsymbol {v}\mathbf {/} \boldsymbol {h}}^{\mathbf {2}}$ ) was used as a predictor of SM. A coherent specular reflection model was employed to first explore the relationship between $\boldsymbol {R}_{ \boldsymbol {v}\mathbf {/} \boldsymbol {h}}^{\mathbf {2}}$ and SM for different values of soil roughness. That relationship was subsequently applied to estimate SM from $\boldsymbol {R}_{ \boldsymbol {v}\mathbf {/} \boldsymbol {h}}^{\mathbf {2}}$ determined from global positioning system (GPS) signals acquired continuously by a ground-based receiver between May and December 2022 for an area with very smooth bare soil. The results show that the proposed method can estimate the SM of the upper 10-cm layer with high accuracy (with a root-mean-square error (RMSE) of approximately 1.5 vol.%) and demonstrate the potential of the ground-based IP technique as a practical system solution for proximal remote sensing of SM over bare soils .","Global navigation satellite systems reflectometry (GNSS-R); interference power (IP); soil moisture (SM)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-30","","Geoscience and Remote Sensing","Mathematical Geodesy and Positioning","","",""
"uuid:0fb8c6cf-63ef-41c0-aaf5-9e58b7736479","http://resolver.tudelft.nl/uuid:0fb8c6cf-63ef-41c0-aaf5-9e58b7736479","Understanding influences on entrepreneurship educator role identity","Brush, Candida (Arthur M. Blank Center, Wellesley, Massachusetts); Wraae, Birgitte (UCL University College); Nikou, S. (TU Delft Responsible Marketing and Consumer Behavior; Åbo Akademi University)","","2024","Purpose: Despite the considerable increase in research on entrepreneurship education, few studies examine the role of entrepreneurship educators. Similarly, most frameworks from entrepreneurship education recognize the educator’s importance in facilitating instruction and assessment, but the factors influencing the educator role are not well understood. According to the identity theory, personal factors including self-efficacy, job satisfaction and personal values influence the perspective of self, significance and anticipations that an individual in this role associates with it, determining their planning and actions. The stronger the role identity the more likely entrepreneurship educators will be in effectively developing their entrepreneurial skills as well as the overall learning experience of their students. The objective of this study is to pinpoint the factors that affect entrepreneurial role identity. Design/methodology/approach: Drawing upon the identity theory, this study developed a theoretical framework and carried out an empirical investigation involving a survey of 289 entrepreneurship educators across the globe. Structural equation modeling (SEM) technique was applied to analyze and explore the factors that impact the identity of the educators in their role as entrepreneurship teachers. Findings: The findings show that the role identity of entrepreneurship educators is significantly influenced by their self-efficacy, job satisfaction and personal values. Among these factors, self-efficacy and job satisfaction have the most significant impacts on how educators perceive their role. The implications of these results and directions for future research are also discussed. Originality/value: The novelty of the current study is derived from its conceptualization of the antecedents of role perception among entrepreneurship educators. This study stands out as one of the earliest attempts to investigate the factors that shape an individual’s scene of self and professional identity as an entrepreneurship educator. The significance of comprehending the antecedents of role perception lies in the insights it can offer into how educators undertake and execute their role, and consequently, their effectiveness in teaching entrepreneurship.","Entrepreneurship; entrepreneurship educator; role identity; Role perception; Self-efficacy","en","journal article","","","","","","","","","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:e5890b49-ded3-496e-ae99-f8feea5311dc","http://resolver.tudelft.nl/uuid:e5890b49-ded3-496e-ae99-f8feea5311dc","Enabling Technologies for the Navigation and Communication of UAS Operating in the Context of BVLOS","Politi, Elena (Harokopio University of Athens); Purucker, Patrick (University of Applied Sciences Amberg-Weiden); Larsen, Morten (AnyWi Technologies); Reis, Ricardo J. Dos (Embraer Research and Technology Europe); Rajan, R.T. (TU Delft Signal Processing Systems); Penna, Sergio Duarte (CISTER—Research Centre in Real-Time Embedded Computing Systems); Boer, Jan-Floris (Royal Netherlands Aerospace Centre NLR); Rodosthenous, Panagiotis (Information Technology for Market Leadership); Dimitrakopoulos, George (Harokopio University of Athens); Varlamis, Iraklis (Harokopio University of Athens); Höß, Alfred (University of Applied Sciences Amberg-Weiden)","","2024","Unmanned Aerial Systems (UAS) have rapidly gained attraction in recent years as a promising solution to revolutionize numerous applications and meet the growing demand for efficient and timely delivery services due to their highly automated operation framework. Beyond Visual Line of Sight (BVLOS) operations, in particular, offer new means of delivering added-value services via a wide range of applications. This ""plateau of productivity"" holds enormous promise, but it is challenging to equip the drone with affordable technologies which support the BVLOS use case. To close this gap, this work showcases the convergence of the automotive and aviation industries to advance BVLOS aviation for UAS in a practical setting by studying a combination of Commercial Off-The-Shelf (COTS) technologies and systems. A novel risk-based approach of investigating the key technological components, architectures, algorithms, and protocols is proposed that facilitate highly reliable and autonomous BVLOS operations, aiming to enhance the alignment between market and operational needs and to better identify integration requirements between the different capabilities to be developed.","","en","journal article","","","","","","","","","","","Signal Processing Systems","","",""
"uuid:5e2c89e3-6bc0-49ad-8256-1f564d0c3fbd","http://resolver.tudelft.nl/uuid:5e2c89e3-6bc0-49ad-8256-1f564d0c3fbd","On the effectiveness of Reynolds-averaged and subgrid scale models in predicting flows inside car cabins","Grossi, G. (TU Delft Aerodynamics; University of Cassino and Southern Lazio); Arpino, Fausto (University of Cassino and Southern Lazio); Bertone, M. (TU Delft Aerodynamics; University of Cassino and Southern Lazio); Cortellessa, Gino (University of Cassino and Southern Lazio); Sciacchitano, A. (TU Delft Aerodynamics)","","2024","The aim of the present study is to analyze the performances of unsteady Reynolds-averaged Navier-Stokes (URANS) and large eddy simulation (LES) approaches in predicting the airflow patterns inside car cabins and to give insight in the design of computational fluid dynamics simulations of a real car cabin. For this purpose, one eddy viscosity-based turbulence model (shear stress transport k-ω) and two subgrid scale models (wall-adapting local eddy-viscosity and dynamic kinetic energy) were tested, and numerical results were compared with particle image velocimetry measurements carried out on a commercial car. The URANS model exhibited great accuracy in predicting the mean flow behavior and was appreciably outperformed by the LES models only far from the inlet sections. For this reason, it was deemed suitable for conducting further analyses, aimed at characterizing the airflow patterns in winter and summer conditions and performing a thermal comfort analysis. The thermal regime was found to have a very little effect on the air flow patterns, once the quasi-steady state regime is achieved; in fact, both in winter and in summer, the temperature field is fairly uniform within the car cabin, making the contribution of buoyancy negligible and velocity fields to be very similar in the two seasons. Findings also reveal that thermal comfort sensation can be different for passengers sharing the same car but sitting on different seats; this aspect should be considered when designing and operating the ventilation system, since the minimum comfort requirements should be met for all the occupants.","","en","journal article","","","","","","","","","","","Aerodynamics","","",""
"uuid:c72b1d20-f52d-42ad-91b7-001a78a097c6","http://resolver.tudelft.nl/uuid:c72b1d20-f52d-42ad-91b7-001a78a097c6","Systematic review of machine-learning models in orthopaedic trauma an overview and quality assessment of 45 studies","Dijkstra, H. (University Medical Center Groningen); van de Kuit, A. (University Medical Center Groningen); de Groot, T. (University Medical Center Groningen; Harvard Medical School); Canta, O. (University Medical Center Groningen); Groot, O. Q. (University Medical Center Utrecht); Oosterhoff, J.H.F. (TU Delft Information and Communication Technology); Doornberg, J. N. (University Medical Center Groningen; Flinders University of South Australia)","","2024","Aims Machine-learning (ML) prediction models in orthopaedic trauma hold great promise in assisting clinicians in various tasks, such as personalized risk stratification. However, an overview of current applications and critical appraisal to peer-reviewed guidelines is lacking. The objectives of this study are to 1) provide an overview of current ML prediction models in orthopaedic trauma; 2) evaluate the completeness of reporting following the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) statement; and 3) assess the risk of bias following the Prediction model Risk Of Bias Assessment Tool (PROBAST) tool. Methods A systematic search screening 3,252 studies identified 45 ML-based prediction models in orthopaedic trauma up to January 2023. The TRIPOD statement assessed transparent reporting and the PROBAST tool the risk of bias. Results A total of 40 studies reported on training and internal validation; four studies performed both development and external validation, and one study performed only external validation. The most commonly reported outcomes were mortality (33%, 15/45) and length of hospital stay (9%, 4/45), and the majority of prediction models were developed in the hip fracture population (60%, 27/45). The overall median completeness for the TRIPOD statement was 62% (interquartile range 30 to 81%). The overall risk of bias in the PROBAST tool was low in 24% (11/45), high in 69% (31/45), and unclear in 7% (3/45) of the studies. High risk of bias was mainly due to analysis domain concerns including small datasets with low number of outcomes, complete-case analysis in case of missing data, and no reporting of performance measures. Conclusion The results of this study showed that despite a myriad of potential clinically useful applications, a substantial part of ML studies in orthopaedic trauma lack transparent reporting, and are at high risk of bias. These problems must be resolved by following established guidelines to instil confidence in ML models among patients and clinicians. Otherwise, there will remain a sizeable gap between the development of ML prediction models and their clinical application in our day-to-day orthopaedic trauma practice.","","en","review","","","","","","","","","","","Information and Communication Technology","","",""
"uuid:728fb398-9f0e-4752-90ca-304967ca203a","http://resolver.tudelft.nl/uuid:728fb398-9f0e-4752-90ca-304967ca203a","Migration and clinical outcomes of a novel cementless hydroxyapatite-coated titanium acetabular shell: two-year follow-up of a randomized controlled trial using radiostereometric analysis","van der Lelij, Thies J. N. (Leiden University Medical Center); Marang-van de Mheen, P.J. (TU Delft Safety and Security Science; Leiden University Medical Center); Kaptein, Bart L. (Leiden University Medical Center); Koster, Lennard A. (Leiden University Medical Center); Ljung, Peter (Hässleholm Hospital); Nelissen, Rob G. H. H. (Leiden University Medical Center); Toksvig-Larsen, Sören (Hässleholm Hospital; Lund University)","","2024","Aims The objective of this study was to compare the two-year migration and clinical outcomes of a new cementless hydroxyapatite (HA)-coated titanium acetabular shell with its previous version, which shared the same geometrical design but a different manufacturing process for applying the titanium surface. Methods Overall, 87 patients undergoing total hip arthroplasty (THA) were randomized to either a Trident II HA or Trident HA shell, each cementless with clusterholes and HA-coating. All components were used in combination with a cemented Exeter V40 femoral stem. Implant migration was measured using radiostereometric analysis (RSA), with radiographs taken within two days of surgery (baseline), and at three, 12, and 24 months postoperatively. Proximal acetabular component migration was the primary outcome measure. Clinical scores and patient-reported outcome measures (PROMs) were collected at each follow-up. Results Mean proximal migrations at three, 12, and 24 months were 0.08 mm (95% confidence interval (CI) 0.03 to 0.14), 0.11 mm (95% CI 0.06 to 0.16), and 0.14 mm (95% CI 0.09 to 0.20), respectively, in the Trident II HA group, versus 0.11 mm (95% CI 0.06 to 0.16), 0.12 mm (95% CI 0.07 to 0.17), and 0.14 mm (95% CI 0.09 to 0.19) in the Trident HA group (p = 0.875). No significant differences in translations or rotations between the two designs were found in any other direction. Clinical scores and PROMs were comparable between groups, except for an initially greater postoperative improvement in Hip disability and Osteoarthritis Outcome Symptoms score in the Trident HA group (p = 0.033). Conclusion The Trident II clusterhole HA shell has comparable migration with its predecessor, the Trident hemispherical HA cluster shell, suggesting a similar risk of long-term aseptic loosening. Cite this article: Bone Joint J 2024;106-B(2):136–143.","Radiostereometric analysis; Total hip arthroplasty; Acetabular cup; Aseptic loosening; Migration; Clinical outcome; acetabular shells; hydroxyapatite; titanium; Randomized controlled trial","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-01","","","Safety and Security Science","","",""
"uuid:a019c126-b976-4dff-95f1-65f1ec6560ab","http://resolver.tudelft.nl/uuid:a019c126-b976-4dff-95f1-65f1ec6560ab","Guest Editorial: Advances in AI-assisted radar sensing applications","Vishwakarma, Shelly (University of Southampton); Chetty, Kevin (University College London (UCL)); Le Kernec, Julien (University of Glasgow); Chen, Qingchao (Peking University); Adve, Raviraj (University of Toronto); Gurbuz, Sevgi Zubeyde (University of Alabama); Li, Wenda (Heriot-Watt University); Ram, Shobha Sundar (Indraprastha Institute of Information Technology Delhi (IIIT-Delhi)); Fioranelli, F. (TU Delft Microwave Sensing, Signals & Systems)","","2024","","artificial intelligence; convolutional neural nets; radar signal processing; radar target recognition","en","contribution to periodical","","","","","","","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:807811a2-faf5-4520-ab84-6c383a7a45af","http://resolver.tudelft.nl/uuid:807811a2-faf5-4520-ab84-6c383a7a45af","Review of Integrated Chassis Control Techniques for Automated Ground Vehicles","Skrickij, Viktor (Vilnius Gediminas Technical University); Kojis, Paulius (Vilnius Gediminas Technical University); Šabanovič, Eldar (Vilnius Gediminas Technical University); Shyrokau, B. (TU Delft Intelligent Vehicles); Ivanov, Valentin (Ilmenau University of Technology)","","2024","Integrated chassis control systems represent a significant advancement in the dynamics of ground vehicles, aimed at enhancing overall performance, comfort, handling, and stability. As vehicles transition from internal combustion to electric platforms, integrated chassis control systems have evolved to meet the demands of electrification and automation. This paper analyses the overall control structure of automated vehicles with integrated chassis control systems. Integration of longitudinal, lateral, and vertical systems presents complexities due to the overlapping control regions of various subsystems. The presented methodology includes a comprehensive examination of state-of-the-art technologies, focusing on algorithms to manage control actions and prevent interference between subsystems. The results underscore the importance of control allocation to exploit the additional degrees of freedom offered by over-actuated systems. This paper systematically overviews the various control methods applied in integrated chassis control and path tracking. This includes a detailed examination of perception and decision-making, parameter estimation techniques, reference generation strategies, and the hierarchy of controllers, encompassing high-level, middle-level, and low-level control components. By offering this systematic overview, this paper aims to facilitate a deeper understanding of the diverse control methods employed in automated driving with integrated chassis control, providing insights into their applications, strengths, and limitations.","automated driving; electric vehicles; integrated chassis control; vehicle dynamics; vehicle state estimation; control allocation; sensors","en","review","","","","","","","","","","","Intelligent Vehicles","","",""
"uuid:e3cf26d1-86b2-4e2b-9c82-412386b37f6b","http://resolver.tudelft.nl/uuid:e3cf26d1-86b2-4e2b-9c82-412386b37f6b","Drivers for optimum sizing of wind turbines for offshore wind farms","Mehta, M.K. (TU Delft Wind Energy); Zaaijer, M B (TU Delft Wind Energy); von Terzi, D.A. (TU Delft Wind Energy)","","2024","Large-scale exploitation of offshore wind energy is deemed essential to provide its expected share to electricity needs of the future. To achieve the same, turbine and farm-level optimizations play a significant role. Over the past few years, the growth in the size of turbines has massively contributed to the reduction in costs. However, growing turbine sizes come with challenges in rotor design, turbine installation, supply chain, etc. It is, therefore, important to understand how to size wind turbines when minimizing the levelized cost of electricity (LCoE) of an offshore wind farm. Hence, this study looks at how the rated power and rotor diameter of a turbine affect various turbine and farm-level metrics and uses this information in order to identify the key design drivers and how their impact changes with setup. A multi-disciplinary design optimization and analysis (MDAO) framework is used to perform the analysis. The framework uses low-fidelity models that capture the core dependencies of the outputs on the design variables while also including the trade-offs between various disciplines of the offshore wind farm. The framework is used, not to estimate the LCoE or the optimum turbine size accurately, but to provide insights into various design drivers and trends. A baseline case, for a typical setup in the North Sea, is defined where LCoE is minimized for a given farm power and area constraint with the International Energy Agency 15 MW reference turbine as a starting point. It is found that the global optimum design, for this baseline case, is a turbine with a rated power of 16 MW and a rotor diameter of 236 m. This is already close to the state-of-the-art designs observed in the industry and close enough to the starting design to justify the applied scaling. A sensitivity study is also performed that identifies the design drivers and quantifies the impact of model uncertainties, technology/cost developments, varying farm design conditions, and different farm constraints on the optimum turbine design. To give an example, certain scenarios, like a change in the wind regime or the removal of farm power constraint, result in a significant shift in the scale of the optimum design and/or the specific power of the optimum design. Redesigning the turbine for these scenarios is found to result in an LCoE benefit of the order of 1 %–2 % over the already optimized baseline. The work presented shows how a simplified approach can be applied to a complex turbine sizing problem, which can also be extended to metrics beyond LCoE. It also gives insights into designers, project developers, and policy makers as to how their decision may impact the optimum turbine scale.","","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:6684d85d-708e-4459-abc8-4b0d488f2581","http://resolver.tudelft.nl/uuid:6684d85d-708e-4459-abc8-4b0d488f2581","Posterolateral or Direct Lateral Surgical Approach for Hemiarthroplasty After a Hip Fracture: A Randomized Clinical Trial Alongside a Natural Experiment","Tol, Maria C.J.M. (Onze Lieve Vrouwe Gasthuis); Willigenburg, Nienke W. (Onze Lieve Vrouwe Gasthuis); Willems, Hanna C. (Amsterdam UMC); Gosens, Taco (ETZ Tilburg; Tilburg University); Heetveld, Martin J. (Spaarne Gasthuis); Eggen, B. (TU Delft Statistics); Kormos, M. (TU Delft Statistics); van der Pas, Stéphanie L. (Vrije Universiteit Amsterdam; Amsterdam Public Health); van der Vaart, A.W. (TU Delft Statistics)","","2024","Importance: Hip fractures in older adults are serious injuries that result in disability, higher rates of illness and death, and a substantial strain on health care resources. High-quality evidence to improve hip fracture care regarding the surgical approach of hemiarthroplasty is lacking. Objective: To compare 6-month outcomes of the posterolateral approach (PLA) and direct lateral approach (DLA) for hemiarthroplasty in patients with acute femoral neck fracture. Design, Setting, and Participants: This multicenter, randomized clinical trial (RCT) comparing DLA and PLA was performed alongside a natural experiment (NE) at 14 centers in the Netherlands. Patients aged 18 years or older with an acute femoral neck fracture were included, with or without dementia. Secondary surgery of the hip, pathological fractures, or patients with multitrauma were excluded. Recruitment took place between February 2018 and January 2022. Treatment allocation was random or pseudorandom based on geographical location and surgeon preference. Statistical analysis was performed from July 2022 to September 2022. Exposure: Hemiarthroplasty using PLA or DLA. Main Outcome and Measures: The primary outcome was health-related quality of life 6 months after surgery, quantified with the EuroQol Group 5-Dimension questionnaire (EQ-5D-5L). Secondary outcomes included dislocations, fear of falling and falls, activities of daily living, pain, and reoperations. To improve generalizability, a novel technique was used for data fusion of the RCT and NE. Results: A total of 843 patients (542 [64.3%] female; mean [SD] age, 82.2 [7.5] years) participated, with 555 patients in the RCT (283 patients in the DLA group; 272 patients in the PLA group) and 288 patients in the NE (172 patients in the DLA group; 116 patients in the PLA group). In the RCT, mean EQ-5D-5L utility scores at 6 months were 0.50 (95% CI, 0.45-0.55) after DLA and 0.49 (95% CI, 0.44-0.54) after PLA, with 77% completeness. The between-group difference (-0.04 [95% CI, -0.11 to 0.04]) was not statistically significant nor clinically meaningful. Most secondary outcomes were comparable between groups, but PLA was associated with more dislocations than DLA (RCT: 15 of 272 patients [5.5%] in PLA vs 1 of 283 patients [0.4%] in DLA; NE: 6 of 113 patients [5.3%]) in PLA vs 2 of 175 patients [1.1%] in DLA). Data fusion resulted in an effect size of 0.00 (95% CI, -0.04 to 0.05) for the EQ-5D-5L and an odds ratio of 12.31 (95% CI, 2.77 to 54.70) for experiencing a dislocation after PLA. Conclusions and Relevance: This combined RCT and NE found that among patients treated with a cemented hemiarthroplasty after an acute femoral neck fracture, PLA was not associated with a better quality of life than DLA. Rates of dislocation and reoperation were higher after PLA. Randomized and pseudorandomized data yielded similar outcomes, which suggests a strengthening of these findings. Trial Registration: ClinicalTrials.gov Identifier: NCT04438226.","","en","journal article","","","","","","","","","","","Statistics","","",""
"uuid:548f421a-572e-4a0e-8f52-624e87b40d52","http://resolver.tudelft.nl/uuid:548f421a-572e-4a0e-8f52-624e87b40d52","Modeling of inflicted head injury by shaking trauma in children: what can we learn?: Update to parts I&II: A systematic review of animal, mathematical and physical models","Hutchinson, K. (TU Delft Medical Instruments & Bio-Inspired Technology); van Zandwijk, Jan Peter (Netherlands Forensic Institute - NFI); Vester, Marloes E.M. (Care Needs Assessment Centre CIZ); Seth, A. (TU Delft Biomechatronics & Human-Machine Control); Bilo, Rob A.C. (Veilig Thuis Rotterdam Rijnmond); van Rijn, Rick R. (Netherlands Forensic Institute - NFI; Amsterdam UMC); Loeve, A.J. (TU Delft Medical Instruments & Bio-Inspired Technology)","","2024","Inflicted shaking trauma can cause injury in infants, but exact injury mechanisms remain unclear. Controversy exists, particularly in courts, whether additional causes such as impact are required to produce injuries found in cases of (suspected) shaking. Publication rates of studies on animal and biomechanical models of inflicted head injury by shaking trauma (IHI-ST) in infants continue rising. Dissention on the topic, combined with its legal relevance, makes maintaining an up-to-date, clear and accessible overview of the current knowledge-base on IHI-ST essential. The current work reviews recent (2017–2023) studies using models of IHI-ST, serving as an update to two previously published reviews. A systematic review was conducted in Scopus and PubMed for articles using animal, physical and mathematical models for IHI-ST. Using the PRISMA methodology, two researchers independently screened the publications. Two, five, and ten publications were included on animal, physical, and mathematical models of IHI-ST, respectively. Both animal model studies used rodents. It is unknown to what degree these can accurately represent IHI-ST. Physical models were used mostly to investigate gross head-kinematics during shaking. Most mathematical models were used to study local effects on the eye and the head’s internal structures. All injury thresholds and material properties used were based on scaled adult or animal data. Shaking motions used as inputs for animal, physical and mathematical models were mostly greatly simplified. Future research should focus on using more accurate shaking inputs for models, and on developing or and validating accurate injury thresholds applicable for shaking.","Animal models; Biomechanical models; Child abuse; Closed head injuries; Forensic pathology","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-18","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:e661bc93-dba4-4b65-a1bf-c9ae79081bec","http://resolver.tudelft.nl/uuid:e661bc93-dba4-4b65-a1bf-c9ae79081bec","The lasting impact of formation cycling on the Li-ion kinetics between SEI and the Li-metal anode and its correlation with efficiency","Zhang, S. (TU Delft RST/Storage of Electrochemical Energy); Li, Yuhang (Tsinghua University); Bannenberg, L.J. (TU Delft RID/TS/Instrumenten groep); Liu, Ming (Tsinghua University); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2024","Formation cycling is a critical process aimed at improving the performance of lithium ion (Li-ion) batteries during subsequent use. Achieving highly reversible Li-metal anodes, which would boost battery energy density, is a formidable challenge. Here, formation cycling and its impact on the subsequent cycling are largely unexplored. Through solid-state nuclear magnetic resonance (ssNMR) spectroscopy experiments, we reveal the critical role of the Li-ion diffusion dynamics between the electrodeposited Li-metal (ED-Li) and the as-formed solid electrolyte interphase (SEI). The most stable cycling performance is realized after formation cycling at a relatively high current density, causing an optimum in Li-ion diffusion over the Li-metal-SEI interface. We can relate this to a specific balance in the SEI chemistry, explaining the lasting impact of formation cycling. Thereby, this work highlights the importance and opportunities of regulating initial electrochemical conditions for improving the stability and life cycle of lithium metal batteries.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:b0b4b511-818e-4b6e-b7d7-62b4c1ae586f","http://resolver.tudelft.nl/uuid:b0b4b511-818e-4b6e-b7d7-62b4c1ae586f","Computationally Aware Surrogate Models for the Hydrodynamic Response Characterization of Floating Spar-Type Offshore Wind Turbine","Ilardi, Davide (University of Genova); Kalikatzarakis, Miltiadis (University of Strathclyde); Oneto, Luca (University of Genova); Collu, Maurizio (University of Strathclyde); Coraddu, A. (TU Delft Ship Design, Production and Operations)","","2024","Due to increasing environmental concerns and global energy demand, the development of Floating Offshore Wind Turbines (FOWTs) is on the rise. FOWTs offer a promising solution to expand wind farm deployment into deeper waters with abundant wind resources. However, their harsh operating conditions and lower maturity level compared to fixed structures pose significant engineering challenges, notably in the design phase. A critical challenge is the time-consuming hydromechanics analysis traditionally done using computationally intensive Computational Fluid Dynamics (CFD) models. In this study, we introduce Artificial Intelligence-based surrogate models using state-of-the-art Machine Learning algorithms. These surrogate models achieve CFD-level accuracy (within 3% difference) while dramatically reducing computational requirements from minutes to milliseconds. Specifically, we build a surrogate model for characterizing the hydrodynamic response of a floating spar-type offshore wind turbine (including added mass, radiation damping matrices, and hydrodynamic excitation) using computationally efficient shallow Machine Learning models, optimizing the trade-off between computational efficiency and accuracy, based on data generated by a cutting-edge potential-flow code.","accuracy; computational fluid dynamics; computational requirements; Floating offshore wind turbines; hydrodynamic response; machine learning; surrogate models","en","journal article","","","","","","","","","","","Ship Design, Production and Operations","","",""
"uuid:420f7566-25ca-42e0-879d-c371a7f873d9","http://resolver.tudelft.nl/uuid:420f7566-25ca-42e0-879d-c371a7f873d9","Preface: SiliconPV 2023, the 13th international conference on crystalline silicon photovoltaics","Weeber, A.W. (TU Delft Photovoltaic Materials and Devices)","","2024","","","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-24","","","Photovoltaic Materials and Devices","","",""
"uuid:a4e1a4d4-0a31-43c4-9f94-a78eeac07061","http://resolver.tudelft.nl/uuid:a4e1a4d4-0a31-43c4-9f94-a78eeac07061","An adaptive parallel arc-length method","Verhelst, H.M. (TU Delft Ship and Offshore Structures; TU Delft Numerical Analysis); den Besten, J.H. (TU Delft Ship and Offshore Structures); Möller, M. (TU Delft Numerical Analysis)","","2024","Parallel computing is omnipresent in today's scientific computer landscape, starting at multicore processors in desktop computers up to massively parallel clusters. While domain decomposition methods have a long tradition in computational mechanics to decompose spatial problems into multiple subproblems that can be solved in parallel, advancing solution schemes for dynamics or quasi-statics are inherently serial processes. For quasi-static simulations, however, there is no accumulating ‘time’ discretization error, hence an alternative approach is required. In this paper, we present an Adaptive Parallel Arc-Length Method (APALM). By using a domain parametrization of the arc-length instead of time, the multi-level error for the arc-length parametrization is formed by the load parameter and the solution norm. Given coarse approximations of arc-length intervals, finer corrections enable the parallelization of the presented method. This results in an arc-length method that is parallel within a branch and inherently adaptive. This concept is easily extended for bifurcation problems. The performance of the method is demonstrated using isogeometric Kirchhoff-Love shells on problems with snap-through and pitch-fork instabilities and applied to the problem of a snapping meta-material. These results show that parallel corrections are performed in a fraction of the time of the serial initialization, achievable on desktop scale.","Arc-length methods; Parallelisation; Isogeometric analysis; Kirchhoff-Love shell; Post-buckling","en","journal article","","","","","","","","","","","Ship and Offshore Structures","","",""
"uuid:78cc3c05-d711-41e9-8b0e-f791b5c1cb4b","http://resolver.tudelft.nl/uuid:78cc3c05-d711-41e9-8b0e-f791b5c1cb4b","How predictable are macroscopic traffic states: a perspective of uncertainty quantification","Li, G. (TU Delft Transport and Planning); Knoop, V.L. (TU Delft Transport and Planning); van Lint, J.W.C. (TU Delft Transport and Planning)","","2024","Traffic condition forecasting is fundamental for Intelligent Transportation Systems. Besides accuracy, many services require an estimate of uncertainty for each prediction. Uncertainty quantification must consider the inherent randomness in traffic dynamics, the so-called aleatoric uncertainty, and the additional distrust caused by data shortage, the so-called epistemic uncertainty. They together depict how predictable macroscopic traffic is. This study uses deep ensembles of graph neural networks to estimate both types of uncertainty in network-level speed forecasting. Experimental results given by the used model reveal that, although rare congestion patterns arise randomly, the short-term predictability of traffic states is mainly restricted by the irreducible stochasticity in traffic dynamics. The predicted future state bifurcates into congested or free-flowing cases. This study suggests that the potential for improving prediction models through expanding speed and flow data is limited while diversifying data types is crucial.","traffic forecasting; uncertainty quantification; traffic dynamics; predictability","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:151efe59-e26c-4eac-aa83-16a67930ae6e","http://resolver.tudelft.nl/uuid:151efe59-e26c-4eac-aa83-16a67930ae6e","On string vibrations influenced by a smooth obstacle at one of the endpoints","Ihsan, A.F. (Telkom University); van Horssen, W.T. (TU Delft Mathematical Physics); Tuwankotta, J.M. (Institute of Technology Bandung)","","2024","In this paper, the vibrations of a string are considered. At one end of the string, a smooth obstacle is placed and the other end of the string is attached to a fixed point. The contact between the string and the obstacle varies in time, and leads to a linear, moving boundary value problem for the string vibrations. By applying a boundary fixing transformation, the problem is transformed from a linear problem with a moving boundary, to a nonlinear problem with fixed boundaries. It is assumed that the vibrations around the stationary position of the string are small. Explicit approximations of the solution are obtained by using a multiple time-scales perturbation method. Depending on the parameters in the problem, it turns out that three different cases for the obstacle boundary condition have to be considered, that is, Dirichlet, or Neumann, or Robin type of boundary conditions. To avoid an infinite-dimensional system of ordinary differential equations that occurs in the analysis of the modal interactions of the string vibrations, characteristic coordinates are used together with a multiple time-scales approach to analyze the string dynamics in terms of traveling waves in opposite directions. A comparison between a direct numerical integration of the PDE problem and the results obtained by using the aforementioned perturbation approach shows an excellent agreement in the results.","Characteristic coordinates; Modal interactions; Moving boundary problem; Multiple time-scales perturbation method","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-27","","","Mathematical Physics","","",""
"uuid:96fe8373-414d-4e23-854b-9d4b04e30a0e","http://resolver.tudelft.nl/uuid:96fe8373-414d-4e23-854b-9d4b04e30a0e","Applying a logistics cluster typology in spatial planning for circularity: Lessons from a Dutch policy lab","Nefs, Merten (TU Delft Spatial Planning and Strategy)","","2024","The spatial planning of logistics is an emerging topic due to scarcity of land, environmental impacts and the transition to a circular economy. This paper proposes a policy information tool for these issues, including a new logistics cluster typology applied in suitability maps. The validity and applicability of this tool are tested in a Dutch policy lab. The analysis reveals two stakeholder views: one emphasising an informed multilevel dialogue and the other pointing to local freedom of decision making. Applicability can be improved by training, updating and deciding on a clear status of the tool in the policy process.","logistics typology; spatial planning; circular economy; policy tool; policy lab","en","journal article","","","","","","","","","","","Spatial Planning and Strategy","","",""
"uuid:28141475-92bf-45e9-b27c-17dd56021692","http://resolver.tudelft.nl/uuid:28141475-92bf-45e9-b27c-17dd56021692","CFD analysis of the full-scale resistance of an oil tanker in presence of a mud–water interface","Lovato, S. (Maritime Research Institute Netherlands (MARIN)); Toxopeus, S.L. (Maritime Research Institute Netherlands (MARIN)); Settels, J.W. (Maritime Research Institute Netherlands (MARIN)); Keetels, G.H. (TU Delft Offshore and Dredging Engineering); Kirichek, Alex (TU Delft Rivers, Ports, Waterways and Dredging Engineering)","","2024","The presence of mud layers on the bottom of ports and waterways can have negative effects on the hydrodynamic behaviour of marine vessels. This numerical study investigates the effect of muddy seabeds on the full-scale resistance of an oil tanker sailing straight ahead. The objective is to determine the influence of factors such as the densimetric Froude number, UKC and mud rheology at speeds between 3 and 9 knots. The numerical study is conducted using a finite-volume Reynolds-Averaged Navier–Stokes (RANS) flow solver combined with the Volume-Of-Fluid (VOF) method to capture the mud–water interface. At certain critical speeds, the presence of mud increased the ship’s total resistance by up to 15 times compared to the case with solid bottoms. The non-Newtonian rheology of mud was found to influence the ship’s resistance mainly at low speeds and when sailing through the mud layer. This article also shows that, when sailing through mud, the computed resistance at high speeds may be underestimated because of two effects, namely ‘water lubrication’ and ‘numerical ventilation’.","Shallow water; CFD; KVLCC2; Nautical bottom; Mud rheology","en","journal article","","","","","","","","","","","Offshore and Dredging Engineering","","",""
"uuid:575bc204-eebf-47ba-8bb8-15da7edd3f91","http://resolver.tudelft.nl/uuid:575bc204-eebf-47ba-8bb8-15da7edd3f91","A nonlinear repair technique for the MPFA-D scheme in single-phase flow problems and heterogeneous and anisotropic media","Castiel Reis de Souza, A. (TU Delft Numerical Analysis); Elisiário de Carvalho, Darlan Karlo (Universidade Federal de Pernambuco); de Moura Cavalcante, Túlio (Universidade Federal de Pernambuco); Licapa Contreras, Fernando Raul (Universidade Federal de Pernambuco); Edwards, Michael G. (Swansea University); Lyra, Paulo Roberto Maciel (Universidade Federal de Pernambuco)","","2024","A novel Flux Limited Splitting (FLS) non-linear Finite Volume (FV) method for families of linear Control Volume Distributed Multi Point Flux Approximation (CVD-MPFA) schemes is presented. The new formulation imposes a local discrete maximum principal (LDMP) which ensures that the discrete solution is free of spurious oscillations. The FLS scheme can be seen as a natural extension of the M-Matrix Flux Splitting method that splits the MPFA flux components in terms of the Two-Point Flux Approximation (TPFA) flux and Cross Diffusion Terms (CDT), with the addition of a dynamically computed relaxation parameter to the CDT that identifies and locally corrects the regions where the LDMP is violated. Moreover, the whole non-linear procedure was devised as a series of simple straightforward matrix operations. The methodology is presented considering the Multi-Point Flux Approximation with a Diamond (MPFA-D) in what we call the FLS + MPFA-D formulation which is tested using a series of challenging benchmark problems. For all test cases, the FLS repair technique imposes the LDMP and eliminates the spurious oscillations induced by the original MPFA-D method.","Flux Limited Splitting (FLS); Non-linear Repair Technique; Discrete Maximum Principle (DMP); Heterogeneous and Anisotropic media; Unstructured Meshes","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:f46910a1-4031-4927-a5e2-84fb0dd72e3b","http://resolver.tudelft.nl/uuid:f46910a1-4031-4927-a5e2-84fb0dd72e3b","Surface gravity wave-induced drift of floating objects in the diffraction regime","Xiao, Q. (University of Oxford); Calvert, R. (TU Delft Environmental Fluid Mechanics; University of Edinburgh); Yan, S.Q. (University of London); Adcock, T.A.A. (University of Oxford); van den Bremer, T.S. (TU Delft Environmental Fluid Mechanics; University of Oxford)","","2024","Floating objects will drift due to the action of surface gravity waves. This drift will depart from that of a perfect Lagrangian tracer due to both viscous effects (non-potential flow) and wave–body interaction (potential flow). We examine the drift of freely floating objects in regular (non-breaking) deep-water wave fields for object sizes that are large enough to cause significant diffraction. Systematic numerical simulations are performed using a hybrid numerical solver, qaleFOAM, which deals with both viscosity and wave–body interaction. For very small objects, the model predicts a wave-induced drift equal to the Stokes drift. For larger objects, the drift is generally greater and increases with object size (we examine object sizes up to 10% of the wavelength). The effects of different shapes, sizes and submergence depths and steepnesses are examined. Furthermore, we derive a ‘diffraction-modified Stokes drift’ akin to Stokes (Trans. Camb. Phil. Soc., vol. 8, 1847, pp. 411–455), but based on the combination of incident, diffracted and radiated wave fields, which are based on potential-flow theory and obtained using the boundary element method. This diffraction-modified Stokes drift explains both qualitatively and quantitatively the increase in drift. Generally, round objects do not diffract the wave field significantly and do not experience a significant drift enhancement as a result. For box-shape objects, drift enhancement is greater for larger objects with greater submergence depths (we report an increase of 92% for simulations without viscosity and 113% with viscosity for a round-cornered box whose size is 10% of the wavelength). We identify the specific standing wave pattern that arises near the object because of diffraction as the main cause of the enhanced drift. Viscosity plays a small positive role in the enhanced drift behaviour of large objects, increasing the drift further by approximately 20%.","wave-structure interactions","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:03accef9-d307-4fcc-b7a3-54db837cb4df","http://resolver.tudelft.nl/uuid:03accef9-d307-4fcc-b7a3-54db837cb4df","Contributing to health system resilience during pandemics via purchasing and supply strategies: an exploratory system dynamics approach","Götz, Paula (Student TU Delft); Auping, Willem L. (TU Delft Policy Analysis); Hinrichs-Krapels, S. (TU Delft Policy Analysis)","","2024","Background: Health systems worldwide struggled to obtain sufficient personal protective equipment (PPE) and ventilators during the COVID-19 pandemic due to global supply chain disruptions. Our study’s aim was to create a proof-of-concept model that would simulate the effects of supply strategies under various scenarios, to ultimately help decision-makers decide on alternative supply strategies for future similar health system related crises. Methods: We developed a system dynamics model that linked a disease transmission model structure (susceptible, exposed, infectious, recovered (SEIR)) with a model for the availability of critical supplies in hospitals; thereby connecting care demand (patients’ critical care in hospitals), with care supply (available critical equipment and supplies). To inform the model structure, we used data on critical decisions and events taking place surrounding purchase, supply, and availability of PPE and ventilators during the first phase of the COVID-19 pandemic within the English national health system. We used exploratory modelling and analysis to assess the effects of uncertainties on different supply strategies in the English health system under different scenarios. Strategies analysed were: (i) purchasing from the world market or (ii) through direct tender, (iii) stockpiling, (iv) domestic production, (v) supporting innovative supply strategies, or (vi) loaning ventilators from the private sector. Results: We found through our exploratory analysis that a long-lasting shortage in PPE and ventilators is likely to be apparent in various scenarios. When considering the worst-case scenario, our proof-of-concept model shows that purchasing PPE and ventilators from the world market or through direct tender have the greatest influence on reducing supply shortages, compared to producing domestically or through supporting innovative supply strategies. However, these supply strategies are affected most by delays in their shipment time or set-up. Conclusion: We demonstrated that using a system dynamics and exploratory modelling approach can be helpful in identifying the purchasing and supply chain strategies that contribute to the preparedness and responsiveness of health systems during crises. Our results suggest that to improve health systems’ resilience during pandemics or similar resource-constrained situations, purchasing and supply chain decision-makers can develop crisis frameworks that propose a plan of action and consequently accelerate and improve procurement processes and other governance processes during health-related crises; implement diverse supplier frameworks; and (re)consider stockpiling. This proof-of-concept model demonstrates the importance of including critical supply chain strategies as part of the preparedness and response activities to contribute to health system resilience.","Critical medical supply chains; Exploratory modelling and analysis; Health system preparedness; Health system resilience; Health system responsiveness; Personal protective equipment (PPE); System dynamics","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:7e9668b7-e295-4802-b659-328491e357aa","http://resolver.tudelft.nl/uuid:7e9668b7-e295-4802-b659-328491e357aa","Regulatory incentives for transmission system operators under flow-based market coupling","Kenis, Michiel (Katholieke Universiteit Leuven; Flemish Institute for Technological Research; EnergyVille); Bruninx, K. (TU Delft Energie and Industrie; Katholieke Universiteit Leuven); Delarue, Erik (Katholieke Universiteit Leuven; EnergyVille)","","2024","Flow-based market coupling is a critical element of the electricity market in Europe. Transmission System Operators determine the commercial transmission capacity that can be implicitly traded in a zonal day-ahead market. However, this entails a trade-off: higher commercial transmission capacities increase market efficiency, affecting the electricity market prices, but also increase redispatch costs, affecting the network tariff. The decision on the commercial transmission capacity should optimally balance day-ahead welfare and redispatch costs, but depends on the rules and regulated incentives enforced on the TSOs. A MinRAM criterion, i.e., imposing minima for the commercial transmission capacity, is a one-size-fits-all policy without variation in time and space that unlikely leads to optimal transmission capacity allocation and is hard to tune because regulators have incomplete information. Incentive regulation is an alternative policy instrument promoting welfare-maximizing commercial transmission capacities, robust against information asymmetry. We provide a set of mathematical conditions to properly design an incentive scheme that rewards price convergence and penalizes excessive redispatch costs. Therefore, this paper serves as a stepping stone towards tapping the full potential of cross-border trade in zonal markets for policymakers, regulators, TSOs and market participants.","Congestion management; Day-ahead markets; Flow-based market coupling; Incentive regulation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-13","","","Energie and Industrie","","",""
"uuid:a38ea3ca-fd25-49ed-9988-948c08cfb6fc","http://resolver.tudelft.nl/uuid:a38ea3ca-fd25-49ed-9988-948c08cfb6fc","The Scientific Graphic Organizer for Lab Work","Pols, C.F.J. (TU Delft ImPhys/Docenten)","","2024","","","en","journal article","","","","","","","","","","","ImPhys/Docenten","","",""
"uuid:adc79ce6-2035-4804-91a0-087573bf3f8b","http://resolver.tudelft.nl/uuid:adc79ce6-2035-4804-91a0-087573bf3f8b","Wafer-scale uniformity of Dolan-bridge and bridgeless Manhattan-style Josephson junctions for superconducting quantum processors","Muthusubramanian, N. (TU Delft QN/Kavli Nanolab Delft); Finkel, M. (TU Delft QCD/DiCarlo Lab); Duivestein, W.J. (TU Delft QN/Groeblacher Lab); Zachariadis, C. (TU Delft QN/Kavli Nanolab Delft); van der Meer, S.L.M. (TU Delft QCD/DiCarlo Lab); Veen, H.M. (TU Delft QCD/DiCarlo Lab); Beekman, M.C. (TU Delft BUS/TNO STAFF; TNO); Stavenga, T. (TU Delft QCD/DiCarlo Lab); Bruno, A. (TU Delft QN/Kavli Nanolab Delft); DiCarlo, L. (TU Delft QCD/DiCarlo Lab; TU Delft QN/DiCarlo Lab)","","2024","We investigate die-level and wafer-scale uniformity of Dolan-bridge and bridgeless Manhattan-style Josephson junctions, using multiple substrates with and without through-silicon vias (TSVs). Dolan junctions fabricated on planar substrates have the highest yield and lowest room-temperature conductance spread, equivalent to ∼ 100 M H z in transmon frequency. In TSV-integrated substrates, Dolan junctions suffer most in both yield and disorder, making Manhattan junctions preferable. Manhattan junctions show pronounced conductance decrease from wafer center to edge, which we qualitatively capture using a geometric model of spatially-dependent resist shadowing during junction electrode evaporation. Analysis of actual junction overlap areas using scanning electron micrographs supports the model, and further points to a remnant spatial dependence possibly due to contact resistance.","transmon; scalability; through-silicon vias; frequency targeting; Dolan-bridge junction; Manhattan-style junction","en","journal article","","","","","","","","","","","QN/Kavli Nanolab Delft","","",""
"uuid:f8ba8bd4-2b0f-499a-89af-0b667a70ac78","http://resolver.tudelft.nl/uuid:f8ba8bd4-2b0f-499a-89af-0b667a70ac78","Nanocarbon-based sheets: Advances in processing methods and applications","Kostaras, Christos (University of Patras); Pavlou, C. (TU Delft Bio-Electronics; University of Patras; FORTH/ICE-HT); Galiotis, Costas (FORTH/ICE-HT); Dassios, Konstantinos G. (University of Patras)","","2024","As an emerging class of materials, nanocarbons have attracted significant interest for practical applications due to their remarkable mechanical, electrical and thermal properties coupled with high surface areas and tunable surface chemistry. However, challenges like high aspect ratios and poor dispersibility in polymer matrices hinder their widespread use in technological applications. The problems are most prominently resolved with the use of free-standing nanocarbon sheets. The present paper reviews recent advancements in fabricating and utilizing free-standing sheets consisting of various nanocarbons: carbon nanotubes and 2D materials like graphene, graphene oxide, and reduced graphene oxide. It initially delves into the nanomechanics of these sheets, focusing on inter-particle cross-linking and nacre-like microstructures. Energy storage applications are also examined, with emphasis on the role of nanocarbon-based sheets in the enhancement of specific energy capacity and performance retention of batteries, electric double layer supercapacitors, and pseudocapacitors. In the field of electromagnetic interference shielding, the sheets' superior electrical conductivity and microstructures, which amplify internal reflections in the GHz and THz regions, are showcased. Their potential in heat dissipation, owing to their high thermal conductivity and large surface area, is also explored. Additionally, they are reviewed for membrane-based separation processes, specifically gas separation, reverse osmosis, forward osmosis, and pervaporation, highlighting properties like ion selectivity and chlorine resistance. The last discussion concerns the role of nanocarbon-based sheets in catalysis where they can enhance reaction efficiencies and promote sustainable solutions. Either as catalysts and/or supports, with key features such as high surface area, electrical conductivity, and adaptable functionalities, they showcase significant potential in various catalytic processes like electrocatalysis and environmental remediation.","Carbon nanotubes; Graphene; Cross-linking; Energy storage; EMI shielding; Thermal dissipation; Water treatment","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-20","","","Bio-Electronics","","",""
"uuid:7c95d34b-ae83-47db-803c-c2938607758a","http://resolver.tudelft.nl/uuid:7c95d34b-ae83-47db-803c-c2938607758a","Personal Data Comics: A Data Storytelling Approach Supporting Personal Data Literacy","Gomez Ortega, A. (TU Delft Internet of Things); Bourgeois, Jacky (TU Delft Internet of Things); Kortuem, G.W. (TU Delft Internet of Things)","","2024","Most people interact with digital technologies that collect personal data about their behavior and experiences, leaving behind a data trail. The data within this trail is abstract and difficult to interpret; still, people often need to decide about its collection and distribution. Hence, it is paramount to support personal data literacy, for which data visualization approaches have been successful. These approaches focus mostly on data from single sources (e.g., IoT devices at home) or types (e.g., menstrual logs) and fail to capture people’s situated knowledge. We hypothesize that creating data comics can address these limitations and support people in developing personal data literacy. In this paper, we explore how non-data experts create personal data comics, starting from simple data visualizations, and investigate their effectiveness and engagement in the context of pregnancy. Doing so, we identify comic elements that facilitate the autonomous exploration of personal data and provide design recommendations to support independent data comic creation.","Personal Data; Data Literacy; Data Visualization; Data Comics","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Internet of Things","","",""
"uuid:211d9fc2-aab8-455b-85e8-b3328e2b930a","http://resolver.tudelft.nl/uuid:211d9fc2-aab8-455b-85e8-b3328e2b930a","Influence of Scour Protection on the Vertical Bearing Behaviour of Monopiles in Sand","Li, Qiang (Hangzhou City University; PowerChina Huadong Engineering Corporation Limited); Wang, Xinquan (Hangzhou City University); Gavin, Kenneth (TU Delft Geo-engineering); Jiang, Shengxiang (PowerChina Huadong Engineering Corporation Limited); Diao, Hongguo (Hangzhou City University); Wang, Kangyu (Zhejiang University of Technology)","","2024","Extensive studies have been performed on the effectiveness of scour protection against scour erosion progression. But there is little research to date evaluating the effect of scour protection on vertical resistance behaviour of monopile foundations. This paper investigates the influence of scour protection on the vertical loading behaviour of monopiles installed in sand using centrifuge tests and finite element analysis (FEA). Four scour protection widths (1D, 2D, 3D, 4D; where D is the pile diameter) and three scour protection thicknesses (1 m, 2 m, 3 m) were modelled on a pile with a slenderness ratio (L/D) of five. In the FEA, the scour protection mechanism was modelled using two strategies, namely the ‘stress method’ by applying stress and the ‘material method’ by applying virtual material on the seabed surface around the pile. Outcomes between these two strategies were compared, and the contact coefficient δ used in the ‘material method’ for describing the contact effectiveness of the overlaying scour protection material with the pile structure was introduced, providing a more scientific and accurate calculation reference for engineering applications. The results indicated that the vertical capacity of monopiles could be increased by 5% to 23% by adopting the scour protection measure, depending on the scour protection width and scour protection thickness.","piles and piling; scour protection; vertical resistance; finite element methods; centrifuge modelling","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:d30c564e-03ed-42eb-9049-e010cc339fa2","http://resolver.tudelft.nl/uuid:d30c564e-03ed-42eb-9049-e010cc339fa2","Insights into the effect of susceptor rotational speed in CVD reactor on the quality of 4H-SiC epitaxial layer on homogeneous substrates","Tang, Zhuorui (Fudan University); Gu, Lin (Fudan University); Jin, Lei (48th Research Institute of China Electronics Technology Group Corporation); Dai, Kefeng (Jihua Laboratory); Mao, Chaobin (Jihua Laboratory); Wu, Sanzhong (Jihua Laboratory); Zhang, Rongwei (Ningbo Xinsheng Medium Voltage Electrical Appliance Co., Ltd.); Yang, Jinsong (Ningbo Xinsheng Medium Voltage Electrical Appliance Co., Ltd.); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2024","In this work, 4H-SiC homoepitaxial layers were grown on 4°off-axis substrates at different susceptor rotation speeds by using a hot-wall horizontal CVD reactor. The effect of different susceptor rotation speed on the quality of 4H-SiC epitaxial layers in terms of thickness, thickness uniformity, crystallinity, surface morphology and morphological defects was investigated via Fourier transform infrared spectroscopy (FTIR), high-resolution X-ray diffraction (XRD), atomic force microscopy (AFM), confocal differential interference contrast microscopy (CDIC), ultra-violet photo-luminescence spectroscopy (UV-PL), scanning electron microscopy (SEM), and micro-Raman spectroscopy, respectively. A flow field simulation was performed to explain the impact of susceptor rotation speed on the film deposition. The FTIR results suggested that the susceptor rotation speed could be an important factor to adjust thickness uniformity and deposition rate. The XRD patterns showed that crystallinity was independent of the susceptor rotation speed. The surface morphology can be improved by changing the susceptor rotation speed. According to CDIC scans, the down-fall related defects were reduced through the increase in the susceptor rotation speed. The origin of down-fall related defects was interpreted by Raman spectroscopy and speculative models. To sum up, the susceptor rotation speed is a crucial factor in increasing growth rate and improving uniformity. Also, the faster susceptor rotation speed helps reduce the number of down-fall related defects in the hot-wall CVD reactor.","4H-SiC homoepitaxial layer; CVD reactor; susceptor rotation speed; quality; defects","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-15","","","Electronic Components, Technology and Materials","","",""
"uuid:87e5685a-8445-46d2-8629-79a076dcdcb1","http://resolver.tudelft.nl/uuid:87e5685a-8445-46d2-8629-79a076dcdcb1","Effect of temperature on lanthanide charge transition levels and vacuum referred binding energies","Dorenbos, P. (TU Delft RST/Luminescence Materials)","","2024","Location of lanthanide levels in the bandgap, vacuum referred binding energy (VRBE) in the lanthanide ground state and energy of lanthanide charge transition levels (CTLs) are just three different namings for the same concept. A concept of importance for the performance of lanthanide activated compounds. Energy differences of CTLs with the conduction band bottom and valence band top are important when it concerns e.g. lanthanide luminescence, charge carrier trapping, and valence stability. Effect of temperature on CTL energy or VRBE has so far never been addressed despite that luminescence application and thermoluminescence studies may span a temperature range from 10 K to 1000 K. In this work information on the bandgap (or energy of host exciton creation) around 10 K and at RT in compounds is gathered to demonstrate that bandgap decreases by 0.1 eV to 0.3 eV when temperature increases to RT. A similar decrease will be demonstrated for the energy of electron transfer from the VB to a trivalent lanthanide. The findings have consequences for VRBE-diagram construction, i.e. the experimental parameters for such construction should all apply to the same temperature. They also have consequences on how to relate luminescence thermal quenching energy barriers and TL derived electron and hole trap depths with a VRBE diagram. By proper evaluating the effects of temperature, accuracy of VRBE diagrams and consistency with luminescence and thermoluminescence data can be improved.","","en","journal article","","","","","","","","","","","RST/Luminescence Materials","","",""
"uuid:ae3b0cd6-c963-4115-bebf-b3848e1b07a3","http://resolver.tudelft.nl/uuid:ae3b0cd6-c963-4115-bebf-b3848e1b07a3","PMUT and CMUT Devices for Biomedical Applications: A Review","Moisello, Elisabetta (Pavia University); Novaresi, Lara (Pavia University); Eshani Sarkar, E. (TU Delft Bio-Electronics); Malcovati, Piero (Pavia University); Lopes Marta da Costa, T.M. (TU Delft Bio-Electronics); Bonizzoni, Edoardo (Pavia University)","","2024","Piezoelectric Micromachined Ultrasonic Transducers (PMUT) and Capacitive Micromachined Ultrasonic Transducers (CMUT) have seen great developments in recent years, both in terms of performance and scope of applications within the biomedical ultrasound domain. This paper presents a review of the state-of-the-art of PMUT and CMUT technologies, focusing on their principle of operation, microfabrication techniques and use in different biomedical imaging and therapeutic applications. The advantages and drawbacks of PMUT and CMUT technologies in comparison with conventional bulk transducers are highlighted, the trade-offs among PMUTs and CMUTs are discussed, and their relevance in the current landscape of medical diagnostics and therapeutic uses is outlined, thus providing a clear overview of these promising technologies for the present and the next generation biomedical ultrasound applications.","PMUT; CMUT; Ultrasound imaging; PAI; neuromodulation; biomedical","en","review","","","","","","","","","","","Bio-Electronics","","",""
"uuid:2e74f03d-65c9-4adb-8195-1d1de80603ca","http://resolver.tudelft.nl/uuid:2e74f03d-65c9-4adb-8195-1d1de80603ca","Numerical study on material removal of a convex pattern surface interacting with non-spherical particles","Yan, Y. (TU Delft Transport Engineering and Logistics; Jilin University); Pargalgauskas, S. (TU Delft Marine and Transport Technology); Helmons, R.L.J. (TU Delft Offshore and Dredging Engineering; Norwegian University of Science and Technology (NTNU)); Schott, D.L. (TU Delft Transport Engineering and Logistics)","","2024","A convex pattern surface is proposed and optimized to mitigate the sliding wear of bulk handling equipment caused by interaction with bulk solids. This work investigates the effectiveness of the convex pattern surface on wear reduction during interactions with non-spherical particles. Multiple representative particles, obtained through a sampling method, are reconstructed using a photogrammetry technique. Two contact parameters between particles are calibrated through shear box and drawdown tests to ensure flow behavior similar to the real material. The numerical results indicate that the convex pattern surface can effectively reduce wear compared to a plain sample when involving both spherical and non-spherical particles. For a plain sample, the wear volume remains independent of particle shapes and increases linearly with numerical revolutions. For the convex pattern surface, the wear volume demonstrates a quadratic relationship with the test revolutions as the deformation of convex elements weakens the effectiveness of the sample on wear reduction. The particle flow behavior analysis reveals that the convex pattern surface experiences the lowest wear volume when in contact with non-spherical particles. This can be attributed to the non-spherical particles sliding shorter distances and rotating with higher angular velocities on the convex pattern surface.","Convex pattern surface; DEM; Particle shape; Wear deformation; Wear reduction","en","journal article","","","","","","","","","","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:fc625a4f-c5bc-4ba2-8a25-1663f031444a","http://resolver.tudelft.nl/uuid:fc625a4f-c5bc-4ba2-8a25-1663f031444a","Identification and Suppression of Multicomponent Noise in Audio Magnetotelluric Data Based on Convolutional Block Attention Module","Zhang, Liang (Guizhou University); Li, Guang (East China University of Technology); Chen, Huang (Chongqing University); Tang, Jingtian (Central South University); Yang, Guanci (Guizhou University); Yu, Mingbiao (Guizhou University); Hu, Yong (China University of Mining and Technology; China University of Petroleum (East China)); Xu, Jun (Guizhou University); Sun, J. (TU Delft Pattern Recognition and Bioinformatics)","","2024","Audio magnetotelluric (AMT) is commonly used in mineral resource exploration. However, the weak energy of AMT signals makes them susceptible to being overwhelmed by noise, leading to erroneous geophysical interpretations. In recent years, deep learning has been applied to AMT denoising and has shown better denoising performance compared to traditional methods. However, current deep learning denoising methods overlook the characteristics of AMT signals, resulting in reduced denoising accuracy. To enhance the denoising performance of deep learning by better matching the features of AMT signals, we propose a convolutional block attention module (CBAM)-based method for AMT denoising. This method focuses on the features of AMT signals and improves the process from three aspects: 1) in the establishment of the sample set, we adopt a multicomponent form based on the correlation of noise to enable the neural network to explore the potential connections among the components of AMT during the training process, thus constructing a stronger network mapping relationship; 2) in the construction of the neural network, we have introduced the CBAM structure into the residual blocks of the ResNet to enhance the network's feature learning capability by focusing on the characteristics of noise; and 3) in the design of the denoising procedure, we adopt a process of identification before denoising to protect the noise-free data segments from being compromised during the denoising process. Finally, through synthetic, field data experiments, and comparative tests, we demonstrate that our proposed method achieves higher denoising accuracy than some traditional methods and conventional deep learning methods.","Convolutional Block Attention Module (CBAM); ResNet; Audio Magnetotelluric (AMT); Denoising","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Pattern Recognition and Bioinformatics","","",""
"uuid:e1c7a606-e0d5-4a7e-b99b-023215b16166","http://resolver.tudelft.nl/uuid:e1c7a606-e0d5-4a7e-b99b-023215b16166","GLOBGM v1.0: a parallel implementation of a 30 arcsec PCR-GLOBWB-MODFLOW global-scale groundwater model","Verkaik, Jarno (Deltares; Universiteit Utrecht); Sutanudjaja, Edwin H. (Universiteit Utrecht); Oude Essink, Gualbert H.P. (Deltares; Universiteit Utrecht); Lin, H.X. (TU Delft Mathematical Physics; Universiteit Leiden); Bierkens, Marc F.P. (Universiteit Utrecht; Deltares)","","2024","We discuss the various performance aspects of parallelizing our transient global-scale groundwater model at 30′′ resolution (30arcsec; °1/41km at the Equator) on large distributed memory parallel clusters. This model, referred to as GLOBGM, is the successor of our 5′ (5arcmin; °1/410km at the Equator) PCR-GLOBWB 2 (PCRaster Global Water Balance model) groundwater model, based on MODFLOW having two model layers. The current version of GLOBGM (v1.0) used in this study also has two model layers, is uncalibrated, and uses available 30′′ PCR-GLOBWB data. Increasing the model resolution from 5′ to 30′′ creates challenges, including increased runtime, memory usage, and data storage that exceed the capacity of a single computer. We show that our parallelization tackles these problems with relatively low parallel hardware requirements to meet the needs of users or modelers who do not have exclusive access to hundreds or thousands of nodes within a supercomputer. For our simulation, we use unstructured grids and a prototype version of MODFLOW 6 that we have parallelized using the message-passing interface. We construct independent unstructured grids with a total of 278 million active cells to cancel all redundant sea and land cells, while satisfying all necessary boundary conditions, and distribute them over three continental-scale groundwater models (168 million - Afro-Eurasia; 77 million - the Americas; 16 million - Australia) and one remaining model for the smaller islands (17 million). Each of the four groundwater models is partitioned into multiple non-overlapping submodels that are tightly coupled within the MODFLOW linear solver, where each submodel is uniquely assigned to one processor core, and associated submodel data are written in parallel during the pre-processing, using data tiles. For balancing the parallel workload in advance, we apply the widely used METIS graph partitioner in two ways: it is straightforwardly applied to all (lateral) model grid cells, and it is applied in an area-based manner to HydroBASINS catchments that are assigned to submodels for pre-sorting to a future coupling with surface water. We consider an experiment for simulating the years 1958-2015 with daily time steps and monthly input, including a 20-year spin-up, on the Dutch national supercomputer Snellius. Given that the serial simulation would require °1/44.5 months of runtime, we set a hypothetical target of a maximum of 16h of simulation runtime. We show that 12 nodes (32 cores per node; 384 cores in total) are sufficient to achieve this target, resulting in a speedup of 138 for the largest Afro-Eurasia model when using 7 nodes (224 cores) in parallel. A limited evaluation of the model output using the United States Geological Survey (USGS) National Water Information System (NWIS) head observations for the contiguous United States was conducted. This showed that increasing the resolution from 5′ to 30′′ results in a significant improvement with GLOBGM for the steady-state simulation when compared to the 5′ PCR-GLOBWB groundwater model. However, results for the transient simulation are quite similar, and there is much room for improvement. Monthly and multi-year total terrestrial water storage anomalies derived from the GLOBGM and PCR-GLOBWB models, however, compared favorably with observations from the GRACE satellite. For the next versions of GLOBGM, further improvements require a more detailed (hydro)geological schematization and better information on the locations, depths, and pumping rates of abstraction wells.","","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:7d2394ed-3835-442e-ae30-02fe08172173","http://resolver.tudelft.nl/uuid:7d2394ed-3835-442e-ae30-02fe08172173","The Road Network Design Problem for the Deployment of Automated Vehicles (RNDP-AVs): A Nonlinear Programming Mathematical Model","Conceição, Lígia (Universidade do Porto); Correia, Gonçalo (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Tavares, José Pedro (Universidade do Porto)","","2024","Once trusted, automated vehicles (AVs) will gradually appear in urban areas. Such a transition is an opportunity in transport planning to control undesired impacts and possibly mitigate congestion at a time when both conventional vehicles (CVs) and AVs coexist. This paper deals with the complex transport decision problem of designing part of the network that is exclusive for AVs through a nonlinear programming model. The objective function minimises the costs of travel times where vehicles circulate under user equilibrium. The model evaluates the benefits of having an AVs-dedicated infrastructure and the associated costs from the detouring of CVs. Three planning strategies are explored: incremental, long-term and hybrid planning. The first creates a subnetwork evolving incrementally over time. The second reversely designs a subnetwork from the optimal solution obtained at a ratio of 90% AVs. The third limits the incremental planning towards that optimal long-term solution. The model is applied to the city of Delft, in the Netherlands. Two scenarios are analysed, with and without AV-dedicated roads, at several AV penetration rates. We find that implementing dedicated roads for AVs reduces the overall costs and congestion up to 16%. However, CV detouring is inevitable at later network stages, increasing the total distance travelled (up to 8%) and congestion in the surroundings of AV subnetworks. Concerning the planning strategies, incremental planning is appropriate for starting in the initial stages and is the strategy that most tackles CV detouring. The hybrid or the long-term strategies are more suitable to be applied after a ratio of 50% AVs, and the hybrid planning is the strategy that most reduces delay.","automated vehicles; mathematical programming; optimisation; road network design problem","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:49b6f6d6-dfa8-4af5-8c72-36cc0990a8d6","http://resolver.tudelft.nl/uuid:49b6f6d6-dfa8-4af5-8c72-36cc0990a8d6","Investigation of petrophysical and hydrogeological parameters of the transboundary Nubian Aquifer system using geophysical methods","Mohammed, Musaab A. A. (University of Miskolc; University of Bahri); Mohamed, Ahmed (Assiut University); Szabó, Norbert P. (University of Miskolc); Alarifi, Saad S. (King Saud University); Abdelrady, Ahmed (TU Delft Water Resources); Alao, Joseph Omeiza (Air Force Institute of Technology)","","2024","The recent research aims to investigate the petrophysical and hydrogeological parameters of the Nubian aquifer system (NAS) in Northern Khartoum State, Sudan, using integrated geophysical methods, including surface electrical resistivity and geophysical well-logging. The Nubian aquifer is a transboundary regional aquifer that covers vast areas in Sudan, Egypt, Libya and Chad. The well-logs, including self-potential (SP), natural gamma ray (GR), and long normal resistivity (RS), are integrated with Vertical Electrical Sounding (VES) measurements to delineate the hydrostratigraphical units. As a result, two aquifers are detected. An upper aquifer comprises coarse sand with an average thickness of 50 m and a lower aquifer of sandstone with more than 200 m thickness. For a thorough evaluation of the aquifers, in the first stage, the petrophysical and hydrogeological parameters, including formation factor, total and effective porosity, shale volume, hydraulic conductivity, and transmissivity, are measured solely from geophysical well-logs. In the second step, the results of geophysical well logs are combined with VES and pumping test data to detect the spatial variation of the measured parameters over the study area. As a result, the hydraulic conductivity of the Nubian aquifers ranged from 1.9 to 7.8 m/day, while the transmissivity varied between 120 and 733 m2/day. These results indicated that the potentiality of the Nubian formation is high; however, in some regions, due to the sediment heterogeneity, the aquifers have intermediate to high potential. According to the obtained results, it can be concluded that the Nubian Aquifer in Khartoum state is ideal for groundwater development. This research discovered that geophysical approaches can be used to characterize moderately heterogeneous groundwater systems by comparing the Nubian aquifer with similar aquifer systems that have similar hydrogeological settings. This study emphasized the application of universal principles in extrapolating hydraulic parameters in hydrogeophysical surveys. This approach aims to reduce the costs and efforts associated with traditional hydrogeological approaches.","well logs; vertical electrical sounding; pumping test; hydraulic conductivity; transmissivity","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:d69ee37f-6416-4a5b-9244-77b3bef2f110","http://resolver.tudelft.nl/uuid:d69ee37f-6416-4a5b-9244-77b3bef2f110","Scour Effect on the Lateral Bearing Behaviour of Monopiles Considering Different Slenderness Ratios","Li, Qiang (Hangzhou City University; PowerChina Huadong Engineering Corporation Limited); Wang, Xinquan (Hangzhou City University); Gavin, Kenneth (TU Delft Geo-engineering); Jiang, Shengxiang (PowerChina Huadong Engineering Corporation Limited); Diao, Hongguo (Hangzhou City University); Wang, Mingyuan (PowerChina Huadong Engineering Corporation Limited); Wang, Kangyu (Zhejiang University of Technology)","","2024","Scour leads to the loss of soil around monopile foundations for offshore wind turbines, which affects their structural safety. In this paper, the effect of scour on the lateral behaviour of monopiles was extensively investigated using finite element analysis, and calibration and comparison were undertaken using centrifuge tests. Piles with three slenderness ratios, i.e., 3, 5 and 8, were studied by keeping the diameter constant and varying the embedment length. Three scour types (local narrow, local wide and global) and four scour depths (0.5D, 1D, 1.5D and 2D; D signifies the pile diameter) were considered in this investigation. The results indicate that the lateral resistance of the pile is the greatest in the case of local narrow scour, followed by that in the cases of local wide scour and global scour. When the scour depth is larger than 1D, the influence of the scour type on the pile lateral bearing behaviour is insignificant. The influence of the scour type and scour depth on the pile lateral bearing behaviour is broadly similar for piles with slenderness ratios of 3, 5 and 8. However, the piles featured with smaller embedment lengths show a larger decrease rate in their lateral capacity, which means the effect of scour should cause more concern on small slenderness ratio monopiles.","piles and piling; scour; finite element methods; centrifuge modelling; lateral bearing behaviour","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:d288d546-2869-4b3c-a54a-13d1c1ad3532","http://resolver.tudelft.nl/uuid:d288d546-2869-4b3c-a54a-13d1c1ad3532","Climate footprint of industry-sponsored clinical research: an analysis of a phase-1 randomised clinical study and discussion of opportunities to reduce its impact","LaRoche, J.K.L. (TU Delft Design for Sustainability; Janssen Research and Development); Alvarenga, Rodrigo (Environmental Resources Management, Ghent); Collins, Michael (Environmental Resources Management, Edinburgh); Costelloe, Thomas (Environmental Resources Management, Bletchley); Soete, Wouter De; Faludi, Jeremy (TU Delft Design for Sustainability); Rens, Kristel (6 Janssen Pharmaceutica NV, Beerse)","","2024","OBJECTIVE: This study aims to calculate the global warming potential, in carbon dioxide (CO2) equivalent emissions, from all in-scope activities involved in a phase-1 clinical study. DESIGN: Retrospective analysis. DATA SOURCE: Internal data held by Janssen Pharmaceuticals. STUDIES INCLUDED: Janssen-sponsored TMC114FD1HTX1002 study conducted between 2019 and 2021. MAIN OUTCOME: Measure CO2 equivalents (CO2e) for in-scope clinical trial activities calculated according to intergovernmental panel on climate change 2021 impact assessment methodology. RESULTS: The CO2e emissions generated by the trial were 17.65 tonnes. This is equivalent to the emissions generated by driving an average petrol-fueled family car 71 004 km or roughly 1.8 times around the circumference of the Earth. Commuting to the clinical site by the study participants generated the most emissions (5419 kg, 31% of overall emissions), followed by trial site utilities (2725 kg, 16% of overall emissions) and site staff travel (2560 kg, 15% of overall emissions). In total, the movement of people (participant travel, site staff travel and trial site staff travel) accounted for 8914 kg or 51% of overall trial emissions. CONCLUSIONS: Decentralised trial models which seek to bring clinical trial operations closer to the participant offer opportunities to reduce participant travel. The electrification of sponsor vehicle fleets and society's transition towards electric vehicles may result in further reductions. TRIAL REGISTRATION NUMBER: NCT04208061.","","en","journal article","","","","","","","","","","","Design for Sustainability","","",""
"uuid:41f09a94-213b-4c70-aade-9bd56a1e53c8","http://resolver.tudelft.nl/uuid:41f09a94-213b-4c70-aade-9bd56a1e53c8","A new power-law model for μ–Λ relationships in convective and stratiform rainfall","Gatidis, C. (TU Delft Atmospheric Remote Sensing); Schleiss, M.A. (TU Delft Atmospheric Remote Sensing); Unal, C.M.H. (TU Delft Atmospheric Remote Sensing)","","2024","In this study, we take a closer look at the important issue of μ–Λ relationships in raindrop size distributions (DSDs) by conducting a systematic analysis of 20 months of data collected by disdrometers in the Netherlands. A new power-law model for representing μ–Λ relationships based on the double normalization framework is proposed and used to derive separate μ–Λ relationships for stratiform and convective rain events. The sensitivity of the obtained relationships to measurement uncertainty is studied by applying two different quality control filters based on the mass-weighted mean drop diameter (Dm) and liquid water content (LWC). Our results show that there are significant differences in μ–Λ relationships between convective and stratiform rainfall types. However, the retrieved relationships appear to be quite robust to measurement noise and there is good agreement with other reference relations for similar climatological conditions.","","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:e36e2f50-e8d7-4ec6-bc0a-e73203fee4c4","http://resolver.tudelft.nl/uuid:e36e2f50-e8d7-4ec6-bc0a-e73203fee4c4","From acceptance to continuance: Understanding the influence of initial participation experience on residents' intentions to continue participation in neighborhood rehabilitation","Li, Y. (TU Delft Design & Construction Management); Zhuang, T. (Chongqing University); Qian, QK (TU Delft Design & Construction Management); Mlecnik, E. (TU Delft Real Estate Management); Visscher, H.J. (TU Delft Design & Construction Management)","","2024","In the context of increasing focus on social sustainability, neighborhood rehabilitation has emerged as a crucial component of global urban renewal initiatives. Distinct from most renewal paradigms that are usually one-offs, neighborhood rehabilitation is a long-term endeavor that requires ongoing resident participation to effectively address diverse needs, investment shortages, and governance challenges. Extant research predominantly focuses on residents' initial engagement, leaving the dynamics of continued participation and its influencing factors largely unexamined. Employing the Expectation-Confirmation Model (ECM), this study explores how residents' initial participation experiences influence their intentions to continue participation. Analyzing questionnaire responses from 367 experienced residents in Wuhan, China, the study finds that a mere 38.2 % of residents exhibit re-engage intention. Path analysis shows that initial participation experience influences residents' re-engage intention indirectly through participation satisfaction and perceived usefulness. Residents' re-engage intention is most influenced by level of influence residents hold in decision-making, followed by type of activities they engage in, and stage of their initial involvement. As an exploratory study into the realm of continued participation, this research uncovers several potential pathways and policy recommendations, aiming to ease residents' transition from initial acceptance to sustained engagement in future neighborhood development efforts.","neighborhood rehabilitation; urban renewal; resident participation; continued participation; expectation-confirmation model (ECM); China","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:a6281c78-24d9-414a-98fb-cae0feb03da2","http://resolver.tudelft.nl/uuid:a6281c78-24d9-414a-98fb-cae0feb03da2","Assessment of self-healing behavior of polypropylene fiber-reinforced cement mortar with crystalline admixture: the effects of crack widths, cracking ages, and external conditions","Liu, Baoju (Central South University China); Ye, Huiwen (Central South University China); Jiang, Junyi (Central South University China); Shi, Jinyan (Central South University China); Yalçınkaya, Çağlar (Dokuz Eylul University); Šavija, B. (TU Delft Materials and Environment)","","2024","Crystalline admixture (CA) is an effective self-healing agent for mortar. However, the effects of crack parameters (i.e. crack width and cracking age) and the service environment on the self-healing behavior of CA-containing mortar are not well understood. Herein, the self-healing behavior of mortar containing a self-developed CA was assessed by testing strength recovery, impermeability recovery, and crack closure in pre-cracked specimens. Three initial crack widths (0.2, 0.3, and 0.4 mm), five cracking ages (3, 7, 14, 28, and 56 days), and four external exposure conditions (humidity chamber, air exposure, water immersion, and wet-dry cycles) are investigated. Furthermore, the influence of different external conditions on the healing products at the region of crack and the pore structure of hardened paste containing CA are studied. The results show that adding 4.54% CA into mortar allows rapid healing of 300 μm-wide cracks. Although wider cracks (400 μm) are more difficult to heal, the sorptivity coefficients of the mortars with 400 μm-wide cracks after healing decrease. When the cracks are produced at an earlier age, the pre-cracked specimens have higher recovery ratios of strength and impermeability after healing, and the specimens pe-cracked at a later age still have acceptable compressive strengths after healing. The analysis shows that the strengths and impermeabilities of pre-cracked mortars containing CA exposed to the four external conditions are all recovered. The best self-healing performance is observed for the specimens exposed to water immersion and wet-dry cycles conditions. Somewhat less good self-healing was observed in the specimens exposed to humid chamber condition, while the worst self-healing performance was in the specimens exposed to air exposure condition. This study provides a theoretical basis for the application of novel CAs in cement-based materials.","crack; crystalline admixture; mortar; permeability; Self-healing behavior","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-16","","","Materials and Environment","","",""
"uuid:a2b98301-0ac0-470c-a1d7-23b0f07c5a97","http://resolver.tudelft.nl/uuid:a2b98301-0ac0-470c-a1d7-23b0f07c5a97","Developing a Pedagogical Framework for an Integrated and BIM-Based High-Performance Design Studio: Experimental Case Study","Shahverdi, Amir Farbod (Shahid Beheshti University); Mostafavi, F. (TU Delft Building Knowledge); Roodkoly, Sogand Haghighat (Shahid Beheshti University); Zomorodian, Zahra Sadat (Shahid Beheshti University); Homayouni, Hoda (Shahid Beheshti University)","","2024","As the current environmental crisis and depletion of our energy resources are pushing the Architecture, Engineering, and Construction (AEC) industry toward the design and construction of High-Performance (HP) buildings, new organizational and technological methods of practice, such as Integrated Design Process (IDP) and Building Information Modeling (BIM), have emerged to facilitate this transition. Consequently, Architecture schools are left with the duty of training practitioners with the required holistic vision and technical knowledge for designing HP buildings, technological abilities to work with new BIM tools, collaboration skills to work with cross-disciplinary team members, and theoretical knowledge to run the new processes. Scholars of architectural education are faced with a significant theoretical and practical knowledge gap on how to add all these new layers of knowledge and skills to what is an already saturated curriculum in architecture schools. To address this need, we developed a conceptual framework for teaching an integrated and BIM-based HP design studio for the MS program in Building Science. The experience was successful in creating an effective systematic method for integrating HP design elements in the students' projects, with all the teams achieving their project performance targets in six distinct HP categories of energy consumption, greenhouse gas emissions, health and wellbeing, water management, and resiliency, while meeting reasonable architectural qualities and economic criteria. The key elements of this pedagogical approach, including teamwork, a structured and iterative design process, decision-making mechanism with a high level of attention given to various performance metrics, the use of related BIM technologies, and the evaluation techniques, are introduced, discussed, and recommendations are proposed for future applications.","architectural design; construction; curricula; decision making; energy utilization; gas emissions; greenhouse gases; iterative methods; personnel training; studios; water management","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-11","","","Building Knowledge","","",""
"uuid:bfbac0fe-5094-4ec2-a9da-d80eb84d8dc7","http://resolver.tudelft.nl/uuid:bfbac0fe-5094-4ec2-a9da-d80eb84d8dc7","A comprehensive thermal analysis of icemaking process inside a domestic freezer: Theoretical, numerical and experimental analyses","Akbar Ahmadi, Ali (University of Nebraska Omaha); Hooman, K. (TU Delft Heat Transformation Technology); Rahbari, Alireza (Australian National University)","","2024","Automatic icemakers are integrated into refrigerators to ensure a consistent ice supply and improve energy efficiency. Despite these advantages, a thorough investigation of the automatic icemaking process in domestic refrigerator-freezers is lacking in the literature. This study aims at assessing the performance of automatic icemaking process in a domestic freezer through detailed theoretical, numerical and experimental analyses. A simplistic zero-dimensional transient energy balance model is developed to investigate the heat transfer during different stages of the water solidification process. The convective heat transfer coefficient calculated from the theoretical analysis is used to inform the numerical model. A three-dimensional transient model is proposed to predict the temperature and density variation inside the ice cube modelled as a pyramid. The free surface flow is modelled using volume of fluid method, while enthalpy-porosity method is employed for the water freezing process. The results show a non-uniform temperature distribution throughout the solidification process and that the temperature of the outer frozen layers keeps decreasing with the solidification time. Experiments are conducted to measure the temperature variation of the ice cube. It is shown that the icemaking process is accelerated by around 18 % when the ice-removal temperature is set at −8°C instead of −12 °C, which is a conventional set temperature for ice remover in current domestic freezers.","Domestic freezer; Enthalpy-porosity method; Icemaking; Solidification; Volume of fluid method","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-14","","","Heat Transformation Technology","","",""
"uuid:8e213072-5117-41f0-b9f0-2cc35a8ebc96","http://resolver.tudelft.nl/uuid:8e213072-5117-41f0-b9f0-2cc35a8ebc96","Exploring Multidimensional Modularity: Strategies to Reduce Complexity in Design Activities","Tan, T. (The University of Hong Kong); Mills, Grant (University College London (UCL)); Papadonikolaki, E. (TU Delft Integral Design & Management)","","2024","Modularity is an approach to simplify systems and reduce complexity. However, existing research suggests that a mono-dimensional modularity strategy, focusing solely on one dimension, such as product, process, or organization, might not fully achieve these goals in design activities. This research investigates how combining strategies from various dimensions of modularity can reduce the complexity of large-scale engineering design. The Huoshenshan Hospital, a 1,000-bed hospital designed and built in 10 days, provided an extreme case study of the first emergency hospital to address COVID-19. The research identified 10 different aspects, termed ‘proximities’, which relate to how people perceive the four dimensions of modularity, specifically across organization–process–product–supply-chain dimensions. Additionally, it identified three types of reinforcement relationships aimed at diminishing complexity in design activities: modular alignment (i.e., synchronized alignment and asynchronous alignment), modular complementarity (i.e., subtraction complement and addition complement), and modular incentive relationships. This research highlights that these three types of reinforcement relationships between different dimensions of modularity can reduce complexity, allowing subsystems to support the system in working as a whole.","modularity; engineering design; design activities; construction; case study","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-23","","","Integral Design & Management","","",""
"uuid:0c332370-5673-48e9-894a-66d70de5c225","http://resolver.tudelft.nl/uuid:0c332370-5673-48e9-894a-66d70de5c225","Bridging Field and Laboratory Permeabilities of Pervious Pavement Mixtures Using XRCT-Based Numerical Modeling","Jagadeesh, A. (TU Delft Pavement Engineering); Ong, G. P. (National University of Singapore); Su, Y. M. (National Kaohsiung University of Science and Technology)","","2024","Drainage capacity of pervious pavement mixtures is commonly measured using a falling head permeameter at hydraulic heads much higher than expected in the field. Recent advancements in computational fluid dynamics (CFD)- and X-ray computed tomography (XRCT)-based modeling eliminates the laboratory challenges of maintaining lower hydraulic heads. However, improper characterization in digital image processing (DIP) and finite-volume simulations resulted in significant errors in permeability measurements and fluid flow behavior. In addition, past studies have identified non-Darcy fluid flow characteristics in pervious pavement mixtures following the Izbash and Forchheimer laws. This paper attempts to bridge this research gap by comparing the Darcy and non-Darcy permeability parameters at different laboratory and field hydraulic heads using advanced XRCT-based modeling. It was found from the analyses that the use of laboratory hydraulic head could result in significant underestimation of permeability parameters compared with the field hydraulic heads for Darcy and Izbash equations (by up to 73%), and overestimation for Forchheimer equations (by up to 216%). Fluid flow behavior in pervious mixtures was found to be in transition flow regime (neither laminar nor turbulent) at both laboratory and field hydraulic gradients. Overall, this study can help in a better fundamental understanding of the current limitations of laboratory measurements and the need for XRCT-based numerical modeling to bridge field and laboratory permeabilities of pervious pavement mixtures.","Field hydraulic heads; Finite-volume simulations; Medical X-ray computed tomography (XRCT); Non-Darcy permeability; Pervious pavement","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-24","","","Pavement Engineering","","",""
"uuid:98dcc7af-1d83-417f-9909-7308bdad9b9e","http://resolver.tudelft.nl/uuid:98dcc7af-1d83-417f-9909-7308bdad9b9e","Receding Horizon Re-Ordering of Multi-Agent Execution Schedules","Berndt, Alexander (Overstory B.V.); Van Duijkeren, Niels (Robert Bosch GmbH); Palmieri, Luigi (Robert Bosch GmbH); Kleiner, Alexander (Robert Bosch GmbH); Keviczky, T. (TU Delft Team Tamas Keviczky)","","2024","The trajectory planning for a fleet of automated guided vehicles (AGVs) on a roadmap is commonly referred to as the multi-agent path finding (MAPF) problem, the solution to which dictates each AGV's spatial and temporal location until it reaches its goal without collision. When executing MAPF plans in dynamic workspaces, AGVs can be frequently delayed, e.g., due to encounters with humans or third-party vehicles. If the remainder of the AGVs keeps following their individual plans, synchrony of the fleet is lost and some AGVs may pass through roadmap intersections in a different order than originally planned. Although this could reduce the cumulative route completion time of the AGVs, generally, a change in the original ordering can cause conflicts, such as deadlocks. In practice, synchrony is therefore often enforced by using a MAPF execution policy employing, e.g., an action dependency graph (ADG) to maintain ordering. To safely re-order without introducing deadlocks, we present the concept of the switchable action dependency graph (SADG). Using the SADG, we formulate a comparatively low-dimensional mixed-integer linear program that repeatedly re-orders AGVs in a recursively feasible manner, thus maintaining deadlock-free guarantees, while dynamically minimizing the cumulative route completion time of all AGVs. Various simulations validate the efficiency of our approach when compared to the original ADG method as well as robust MAPF solution approaches.","Mixed integer programming; multi-agent path finding (MAPF); robust plan execution; scheduling and coordination","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-18","","","Team Tamas Keviczky","","",""
"uuid:53155951-f11c-4979-a442-812c0a76929e","http://resolver.tudelft.nl/uuid:53155951-f11c-4979-a442-812c0a76929e","The role of City Climate Networks in Promoting Citizen Participation in Municipalities: A Critical Multi-Case Analysis","Zapata Arango, Mateo (Student TU Delft); Hoppe, T. (TU Delft Organisation & Governance); Itten, A.V. (TU Delft Organisation & Governance); Blok, K. (TU Delft Energie and Industrie)","","2024","Background
At the COP21, cities were recognised as key actors in combatting climate change. In supporting cities, climate city networks such as transnational climate networks (TCNs) and national climate networks (NCNs) have emerged to enable cities in building capacities and formulating climate policy whilst also encouraging citizen engagement and participation in public decision-making. This paper addresses the question whether and how TCN or NCN membership enables municipalities to implement citizen participation in public decision-making. Six propositions are presented addressing: presumed influence of TCN membership on citizen participation, organization of citizen participation, initiator capacity, goal setting, involvement of stakeholders, participatory methods used, and planning processes. A multi-case study research design is used to verify these propositions, comprising of four medium-sized cities in the Netherlands and three in Belgium.
Results
Results of the analysis of four cities in The Netherlands show that municipalities having membership to climate city networks only to a low extent empower citizen participation via local climate agendas. Citizen participation emerges rather bottom-up via local initiatives or capacity building via EU framework programs—outside TCNs or NCNs—that better suit financial needs and provide more immediate benefits to municipalities. None of the six propositions were confirmed. A more positive image resulted from the Belgian cases that moderately confirmed four out of six propositions (i.e., organizing citizen participation, goal setting, selection of methods, and planning), and featured indirect empowerment via externally funded implementation projects following firm integration of participation in local climate policy through TCN influence.
Conclusions
In terms of citizen participation selected municipalities in the Netherlands having TCN and/or NCN membership only to a small extent differ from those not having membership. This is partly due to poor implementation of TCNs and NCNs—with Covenant of Mayors and ‘Klimaatverbond’ lacking support structure and capacity—having lost importance during the past years. However, there is reason to believe that context makes a difference as revealed by the cases from Belgium, which revealed more positive results.","Climate policy; Citizen participation; City climate network; Policy network; Implementation; Energy transition; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Organisation & Governance","","",""
"uuid:935cc7ae-158a-4b98-a142-f2ec0240a768","http://resolver.tudelft.nl/uuid:935cc7ae-158a-4b98-a142-f2ec0240a768","Recycling of Aluminosilicate-Based Solid Wastes through Alkali-Activation: Preparation, Characterization, and Challenges","Feng, Lichao (Jiangsu Ocean University); Yi, Shengjie (Jiangsu Ocean University); Zhao, Shuyuan (Harbin Institute of Technology); Zhong, Qiucheng (Jiangsu Ocean University); Ren, Feirong (Jiangsu Ocean University); Liu, C. (TU Delft Materials and Environment); Zhang, Y. (TU Delft Materials and Environment); Wang, Wenshou (University of Jinan); Li, Zhenming (University of Sheffield)","","2024","Recycling aluminosilicate-based solid wastes is imperative to realize the sustainable development of constructions. By using alkali activation technology, aluminosilicate-based solid wastes, such as furnace slag, fly ash, red mud, and most of the bio-ashes, can be turned into alternative binder materials to Portland cement to reduce the carbon footprint of the construction and maintenance activities of concrete structures. In this paper, the chemistry involved in the formation of alkali-activated materials (AAMs) and the influential factors of their properties are briefly reviewed. The commonly used methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), nuclear magnetic resonance spectroscopy (NMR), and X-ray pair distribution function technology, to characterize the microstructure of AAMs are introduced. Typical characterization results of AAMs are shown and the limitations of each method are discussed. The main challenges, such as shrinkage, creep, efflorescence, carbonation, alkali–silica reaction, and chloride ingress, to conquer for a wider application of AAMs are reviewed. It is shown that several performances of AAMs under certain circumstances seem to be less satisfactory than traditional portland cement systems. Existing strategies to improve these performances are reviewed, and recommendations for future studies are given.","slag; fly ash; alkali-activation; microstructure; performance; challenges","en","review","","","","","","","","","","","Materials and Environment","","",""
"uuid:64164874-7b5c-40fd-82ac-721b0d10f19c","http://resolver.tudelft.nl/uuid:64164874-7b5c-40fd-82ac-721b0d10f19c","Discovering the Significance of Housing Neighbourhoods by Assessing Their Attributes With a Digital Tool","Spoormans, L.G.K. (TU Delft Heritage & Architecture); de Jonge, W. (TU Delft Heritage & Architecture); Czischke, D.K. (TU Delft Real Estate Management); Pereira Roders, A. (TU Delft Heritage & Architecture)","","2024","Much of the building stock subjected to the upcoming European Renovation Wave is neither listed as heritage nor considered valuable architecture. This also applies to Dutch housing built between 1965 and 1985, more than 30% of the Dutch housing stock, for which there is no consensus on their cultural significance. Their successful renovation process requires broad support. What attributes do citizens consider significant in their neighbourhood? How do we include a multitude of stakeholders? And can digital methods help collect and process responses? This article reveals significant attributes of residential neighbourhoods from 1965 to 1985, assessed by various stakeholders with a digital tool based on case studies in Amsterdam and Almere. A mobile application allowed individuals to identify significant attributes at various scales while visiting the neighbourhood. By qualitative data analysis of survey and interview results, groups of tangible and intangible attributes were deduced. Results show that identifying attributes by current stakeholders broadens existing expert-led assessments on 1965–1985 neighbourhoods by including, for example, generic attributes not originally intended by the designers. Asking open-ended questions is considered essential to identify undiscovered attributes by alternative stakeholders, although dealing with large numbers of responses is recognised as a challenge to cluster and classify. Lastly, the mobile application appears to be a useful digital tool, but integrating scientific consistency and usability is recommended for further development. Engaging multiple stakeholders with such mobile applications allows for collecting opinions, anticipating conflicts, or shared interests between stakeholders and integration into renovation designs. It can empower citizens to preserve the neighbourhood attributes that are most significant to them.","cultural significance; heritage attributes; housing neighbourhoods; post-Second World War architecture; participation","en","journal article","","","","","","","","","","","Heritage & Architecture","","",""
"uuid:0fde08de-f91c-4621-8391-8e9a0b44fb12","http://resolver.tudelft.nl/uuid:0fde08de-f91c-4621-8391-8e9a0b44fb12","Accuracy Assessment of Numerical Morphological Models Based on Reduced Saint-Venant Equations","Barneveld, H.J. (Wageningen University & Research; HKV); Mosselman, E. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Deltares); Chavarrías, V. (Deltares); Hoitink, A.J.F. (Wageningen University & Research)","","2024","Sustainable river management often requires long-term morphological simulations. As the future is unknown, uncertainty needs to be accounted for, which may require probabilistic simulations covering a large parameter domain. Even for one-dimensional models, simulation times can be long. One of the acceleration strategies is simplification of models by neglecting terms in the governing hydrodynamic equations. Examples are the quasi-steady model and the diffusive wave model, both widely used by scientists and practitioners. Here, we establish under which conditions these simplified models are accurate. Based on results of linear stability analyses of the St. Venant-Exner equations, we assess migration celerities and damping of infinitesimal, but long riverbed perturbations. We did this for the full dynamic model, that is, no terms neglected, as well as for the simplified models. The accuracy of the simplified models was obtained from comparison between the characteristics of the riverbed perturbations for simplified models and the full dynamic model. We executed a spatial-mode and a temporal-mode linear analysis and compared the results with numerical modeling results for the full dynamic and simplified models, for very small and large bed waves. The numerical results match best with the temporal-mode linear analysis. We show that the quasi-steady model is highly accurate for Froude numbers up to 0.7, probably even for long river reaches with large flood wave damping. Although the diffusive wave model accurately predicts flood wave migration and damping, key morphological metrics deviate more than 5% (10%) from the full dynamic model when Froude numbers exceed 0.2 (0.3).","linear analysis; modeling; morphology; quasi-steady","en","journal article","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:b144ad47-692b-41c8-a9c0-e04096080ff9","http://resolver.tudelft.nl/uuid:b144ad47-692b-41c8-a9c0-e04096080ff9","Effect of Long-Term Sodium Hypochlorite Cleaning on Silicon Carbide Ultrafiltration Membranes Prepared via Low-Pressure Chemical Vapor Deposition","Jan, A. (TU Delft Sanitary Engineering); Chen, M. (TU Delft ChemE/Product and Process Engineering; University of Twente); Nijboer, Michiel (University of Twente); Luiten-Olieman, Mieke W.J. (University of Twente); Rietveld, L.C. (TU Delft Sanitary Engineering); Heijman, Sebastiaan (TU Delft Sanitary Engineering)","","2024","Sodium hypochlorite (NaClO) is widely used for the chemical cleaning of fouled ultrafiltration (UF) membranes. Various studies performed on polymeric membranes demonstrate that long-term (>100 h) exposure to NaClO deteriorates the physicochemical properties of the membranes, leading to reduced performance and service life. However, the effect of NaClO cleaning on ceramic membranes, particularly the number of cleaning cycles they can undergo to alleviate irreversible fouling, remains poorly understood. Silicon carbide (SiC) membranes have garnered widespread attention for water and wastewater treatment, but their chemical stability in NaClO has not been studied. Low-pressure chemical vapor deposition (LP-CVD) provides a simple and economical route to prepare/modify ceramic membranes. As such, LP-CVD facilitates the preparation of SiC membranes: (a) in a single step; and (b) at much lower temperatures (700–900 °C) in comparison with sol-gel methods (ca. 2000 °C). In this work, SiC ultrafiltration (UF) membranes were prepared via LP-CVD at two different deposition temperatures and pressures. Subsequently, their chemical stability in NaClO was investigated over 200 h of aging. Afterward, the properties and performance of as-prepared SiC UF membranes were evaluated before and after aging to determine the optimal deposition conditions. Our results indicate that the SiC UF membrane prepared via LP-CVD at 860 °C and 100 mTorr exhibited excellent resistance to NaClO aging, while the membrane prepared at 750 °C and 600 mTorr significantly deteriorated. These findings not only highlight a novel preparation route for SiC membranes in a single step via LP-CVD, but also provide new insights about the careful selection of LP-CVD conditions for SiC membranes to ensure their long-term performance and robustness under harsh chemical cleaning conditions.","silicon carbide; ultrafiltration; low-pressure chemical vapor deposition; sodiumhypochlorite; chemical aging","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:0fddf122-d78d-4365-8e86-2cab32ade2f7","http://resolver.tudelft.nl/uuid:0fddf122-d78d-4365-8e86-2cab32ade2f7","Towards a pattern language for green space design in high density urban developments","Zhou, S. (TU Delft Urban Design); Nijhuis, S. (TU Delft Landscape Architecture); Dijkstra, R.J. (TU Delft Urban Design)","","2024","In the inevitable high-density urbanization process, existing urban green space (UGS) design approaches are ineffective in creating more green areas and combining multidisciplinary design principles to provide balanced sets of ecosystem services (ESs). This paper proposes a systematic framework for UGS design in the context of high-density urban development, results in spatial patterns, a pattern language, that combines specific design principles with a wide range of complementary ESs suitable for high-density environments. Such design approach can create more possibilities for UGS provisioning, deal with the complexity in high-density contexts, and provides consistency at different scale for UGS designs.","Green space design; high-density urban environment; ecosystem services; pattern language","en","journal article","","","","","","","","","","","Urban Design","","",""
"uuid:293607b7-85ff-45d0-a3e3-31fe04c2c5ed","http://resolver.tudelft.nl/uuid:293607b7-85ff-45d0-a3e3-31fe04c2c5ed","How Hard Is Weak-Memory Testing?","Chakraborty, S.S. (TU Delft Programming Languages); Krishna, Shankara Narayanan (Indian Institute of Technology Bombay); Mathur, Umang (National University of Singapore); Pavlogiannis, Andreas (Aarhus University)","","2024","Weak-memory models are standard formal specifications of concurrency across hardware, programming languages, and distributed systems. A fundamental computational problem is consistency testing: is the observed execution of a concurrent program in alignment with the specification of the underlying system? The problem has been studied extensively across Sequential Consistency (SC) and weak memory, and proven to be NP-complete when some aspect of the input (e.g., number of threads/memory locations) is unbounded. This unboundedness has left a natural question open: are there efficient parameterized algorithms for testing? The main contribution of this paper is a deep hardness result for consistency testing under many popular weak-memory models: the problem remains NP-complete even in its bounded setting, where candidate executions contain a bounded number of threads, memory locations, and values. This hardness spreads across several Release-Acquire variants of C11, a popular variant of its Relaxed fragment, popular Causal Consistency models, and the POWER architecture. To our knowledge, this is the first result that fully exposes the hardness of weak-memory testing and proves that the problem admits no parameterization under standard input parameters. It also yields a computational separation of these models from SC, x86-TSO, PSO, and Relaxed, for which bounded consistency testing is either known (for SC), or shown here (for the rest), to be in polynomial time.","complexity; concurrency; consistency checking; weak memory models","en","journal article","","","","","","","","","","","Programming Languages","","",""
"uuid:553f74d3-2e5a-4ba6-8687-5655473d0120","http://resolver.tudelft.nl/uuid:553f74d3-2e5a-4ba6-8687-5655473d0120","Surface mass balance and climate of the Last Glacial Maximum Northern Hemisphere ice sheets: simulations with CESM2.1","Bradley, Sarah L. (University of Sheffield); Sellevold, R. (TU Delft Physical and Space Geodesy); Petrini, M. (Bjerknes Centre for Climate Research); Vizcaino, M. (TU Delft Physical and Space Geodesy); Georgiou, S. (TU Delft Physical and Space Geodesy); Zhu, Jiang (National Center for Atmospheric Research); Otto-Bliesner, Bette L. (National Center for Atmospheric Research); Lofverstrom, Marcus (University of Arizona)","","2024","The Last Glacial Maximum (LGM, from ∼26 to 20 ka BP) was the most recent period with large ice sheets in Eurasia and North America. At that time, global temperatures were 5–7 ∘C lower than today, and sea level ∼125 m lower. LGM simulations are useful to understand earth system dynamics, including climate–ice sheet interactions, and to evaluate and improve the models representing those dynamics. Here, we present two simulations of the Northern Hemisphere ice sheet climate and surface mass balance (SMB) with the Community Earth System Model v2.1 (CESM2.1) using the Community Atmosphere Model v5 (CAM5) with prescribed ice sheets for two time periods that bracket the LGM period: 26 and 21 ka BP. CESM2.1 includes an explicit simulation of snow/firn compaction, albedo, refreezing, and direct coupling of the ice sheet surface energy fluxes with the atmosphere. The simulated mean snow accumulation is lowest for the Greenland and Barents–Kara Sea ice sheets (GrIS, BKIS) and highest for British and Irish (BIIS) and Icelandic (IcIS) ice sheets. Melt rates are negligible for the dry BKIS and GrIS, and relatively large for the BIIS, North American ice sheet complex (NAISC; i.e. Laurentide, Cordilleran, and Innuitian), Scandinavian ice sheet (SIS), and IcIS, and are reduced by almost a third in the colder (lower temperature) 26 ka BP climate compared with 21 ka BP. The SMB is positive for the GrIS, BKIS, SIS, and IcIS during the LGM (26 and 21 ka BP) and negative for the NAISC and BIIS. Relatively wide ablation areas are simulated along the southern (terrestrial), Pacific and Atlantic margins of the NAISC, across the majority of the BIIS, and along the terrestrial southern margin of the SIS. The integrated SMB substantially increases for the NAISC and BIIS in the 26 ka BP climate, but it does not reverse the negative sign. Summer incoming surface solar radiation is largest over the high interior of the NAISC and GrIS, and minimum over the BIIS and southern margin of NAISC. Summer net radiation is maximum over the ablation areas and minimum where the albedo is highest, namely in the interior of the GrIS, northern NAISC, and all of the BKIS. Summer sensible and latent heat fluxes are highest over the ablation areas, positively contributing to melt energy. Refreezing is largest along the equilibrium line altitude for all ice sheets and prevents 40 %–50 % of meltwater entering the ocean. The large simulated melt for the NAISC suggests potential biases in the climate simulation, ice sheet reconstruction, and/or highly non-equilibrated climate and ice sheet at the LGM time.","","en","journal article","","","","","","","","","","","Physical and Space Geodesy","","",""
"uuid:8d85050b-8534-49f2-9b43-c3176d55fb82","http://resolver.tudelft.nl/uuid:8d85050b-8534-49f2-9b43-c3176d55fb82","Bromate removal in an ozone - granular activated carbon filtration process for organic micropollutants removal from wastewater","van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet); Deng, Tianyi (Student TU Delft; Witteveen+Bos); Spit, Tiza (Witteveen+Bos); Luimstra, Veerle (Witteveen+Bos); de Kreuk, M.K. (TU Delft Water Management); van Halem, D. (TU Delft Sanitary Engineering)","","2024","Organic micropollutants (OMPs) enter the aquatic environment via municipal wastewater treatment plants (WWTPs). As conventional WWTPs have limited capacity for the removal of OMPs, additional processes are required, like ozone - granular activated carbon (GAC) filtration. A specific lay-out of this process is the O3-STEP® process, in which the removal of suspended solids, OMPs, phosphate and nitrate is combined. However, ozonation may result in formation of bromate, a compound with a strict water quality standard of 1 μg/L for surface waters in The Netherlands. This limits the applicability of ozonation in wastewater treatment. This study examined biological bromate removal associated with denitrification processes in the GAC filter of the O3-STEP® process. In this GAC filter methanol is dosed for nitrate removal by biological denitrification. In column experiments, bromate and nitrate were removed simultaneously under both anoxic and oxic conditions. Depletion of oxygen within the biofilm surrounding the GAC granules most probably is the reason for denitrification under oxic bulk conditions, although aerobic denitrification cannot be excluded. In batch experiments, the presence of nitrate did not affect bromate removal, whereas the presence of dissolved oxygen had a slight inhibitory effect on bromate removal and nitrate removal. Addition of methanol increased both nitrate and bromate removal, which is hypothesized to occur through an increased availability of electron donors in the water. The results show that a denitrifying GAC filter in the ozone - GAC filtration process mitigates the bromate formation, which broadens the applicability of this process for OMP removal from wastewater.","Bromate; Denitrification; Nitrate; Organic micropollutants; Ozone – granular activated carbon filtration","en","journal article","","","","","","","","","","Water Management","Sanitary Engineering","","",""
"uuid:fba66db0-cb97-4465-98b5-41b24d149ed5","http://resolver.tudelft.nl/uuid:fba66db0-cb97-4465-98b5-41b24d149ed5","Surface modification of multilayer graphene electrodes by local printing of platinum nanoparticles using spark ablation for neural interfacing","Bakhshaee Babaroud, N. (TU Delft Bio-Electronics); Rice, S.J. (TU Delft EKL Processing); Camarena, M. (Student TU Delft); Serdijn, W.A. (TU Delft Bio-Electronics; Erasmus MC); Vollebregt, S. (TU Delft Electronic Components, Technology and Materials); Giagka, Vasiliki (TU Delft Bio-Electronics; Fraunhofer Institute for Reliability and Microintegration IZM)","","2024","In this paper, we present the surface modification of multilayer graphene electrodes with platinum (Pt) nanoparticles (NPs) using spark ablation. This method yields an individually selective local printing of NPs on an electrode surface at room temperature in a dry process. NP printing is performed as a post-process step to enhance the electrochemical characteristics of graphene electrodes. The NP-printed electrode shows significant improvements in impedance, charge storage capacity (CSC), and charge injection capacity (CIC), versus the equivalent electrodes without NPs. Specifically, electrodes with 40% NP surface density demonstrate 4.5 times lower impedance, 15 times higher CSC, and 4 times better CIC. Electrochemical stability, assessed via continuous cyclic voltammetry (CV) and voltage transient (VT) tests, indicated minimal deviations from the initial performance, while mechanical stability, assessed via ultrasonic vibration, is also improved after the NP printing. Importantly, NP surface densities up to 40% maintain the electrode optical transparency required for compatibility with optical imaging and optogenetics. These results demonstrate selective NP deposition and local modification of electrochemical properties in graphene electrodes for the first time, enabling the cohabitation of graphene electrodes with different electrochemical and optical characteristics on the same substrate for neural interfacing.","","en","journal article","","","","","","","","","","","Bio-Electronics","","",""
"uuid:2dacdbff-780a-4add-8b4a-972e21418ce3","http://resolver.tudelft.nl/uuid:2dacdbff-780a-4add-8b4a-972e21418ce3","Fear of Missing Out: Constrained Trial of Blockchain in Supply Chain","Kromes, R.G. (TU Delft Web Information Systems); Li, T. (TU Delft Cyber Security); Bouillion, Maxime (Windesheim University of Applied Sciences); Güler, Talha Enes (Koç University); van der Hulst, Victor (Windesheim University of Applied Sciences); Erkin, Z. (TU Delft Cyber Security)","","2024","Blockchain’s potential to revolutionize supply chain and logistics with transparency and equitable stakeholder engagement is significant. However, challenges like scalability, privacy, and interoperability persist. This study explores the scarcity of real-world blockchain implementations in supply chain and logistics since we have not witnessed many real-world deployments of blockchain-based solutions in the field. Puzzled by this, we integrate technology, user experience, and operational efficiency to illuminate the complex landscape of blockchain integration. We present blockchain-based solutions in three use cases, comparing them with alternative designs and analyzing them in terms of technical, economic, and operational aspects. Insights from a tailored questionnaire of 50 questions addressed to practitioners and experts offer crucial perspectives on blockchain adoption. One of the key findings from our work shows that half of the companies interviewed agree that they will miss the potential for competitive advantage if they do not invest in blockchain technology, and 61% of the companies surveyed claimed that their customers ask for more transparency in supply chain-related transactions. However, only one-third of the companies were aware of the main features of blockchain technology, which shows a lack of knowledge among the companies that may lead to a weaker blockchain adaption in supply chain use cases. Our readers should note that our study is specifically contextualized in a Netherlands-funded national project. We hope that researchers as well as stakeholders in supply chain and logistics can benefit from the insights of our work.","blockchain; DLT; supply chain; transparency; digital transformation; traceability","en","journal article","","","","","","","","","","","Web Information Systems","","",""
"uuid:3d772f70-28a8-4eba-834b-db2ecaa7a366","http://resolver.tudelft.nl/uuid:3d772f70-28a8-4eba-834b-db2ecaa7a366","The role of drag and gravity on dust concentration in a gravitationally unstable disc","Rowther, Sahl (University of Warwick; University of Leicester); Nealon, Rebecca (University of Warwick); Meru, Farzana (University of Warwick); Wurster, James (University of St Andrews); Aly, H.A. (TU Delft Planetary Exploration; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Alexander, Richard (University of Leicester); Rice, Ken (University of Edinburgh); Booth, Richard A (University of Leeds)","","2024","We carry out three-dimensional smoothed particle hydrodynamics simulations to study the role of gravitational and drag forces on the concentration of large dust grains (St > 1) in the spiral arms of gravitationally unstable protoplanetary discs, and the resulting implications for planet formation. We find that both drag and gravity play an important role in the evolution of large dust grains. If we include both, grains that would otherwise be partially decoupled will become well coupled and trace the spirals. For the dust grains most influenced by drag (with Stokes numbers near unity), the dust disc quickly becomes gravitationally unstable and rapidly forms clumps with masses between 0.15–6M⨁. A large fraction of clumps are below the threshold where runaway gas accretion can occur. However, if dust self-gravity is neglected, the dust is unable to form clumps, despite still becoming trapped in the gas spirals. When large dust grains are unable to feel either gas gravity or drag, the dust is unable to trace the gas spirals. Hence, full physics is needed to properly simulate dust in gravitationally unstable discs. Dust trapping of large grains in spiral arms of discs stable to gas fragmentation could explain planet formation in very young discs by a population of planetesimals formed due to the combined roles of drag and gravity in the earliest stages of a disc’s evolution. Furthermore, it highlights that gravitationally unstable discs are not just important for forming gas giants quickly, it can also rapidly form Earth mass bodies.","Hydrodynamics; protoplanetary disks; planets and satellites: formation","en","journal article","","","","","","","","","","","Planetary Exploration","","",""
"uuid:8ded61c8-bd00-49c9-ab6c-4dcb04206ae6","http://resolver.tudelft.nl/uuid:8ded61c8-bd00-49c9-ab6c-4dcb04206ae6","EV Smart Charging in Distribution Grids - Experimental evaluation using Hardware in the Loop Setup","Yu, Y. (TU Delft DC systems, Energy conversion & Storage); De Herdt, Lode; Shekhar, A. (TU Delft DC systems, Energy conversion & Storage); Chandra Mouli, G.R. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2024","The rising demand for electric vehicles (EVs) in the face of limited grid capacity encourages the development and implementation of smart charging (SC) algorithms. Experimental validation plays a pivotal role in advancing this field. This article formulates a hierarchical mixed integer programming EV SC algorithm designed for low voltage (LV) distribution grid applications. A flexible receding horizon scheme is introduced in response to system uncertainties. It also considers the practical constraints in protocols, such as IEC/ISO 15118 and IEC 61851-1. The proposed algorithm is verified and assessed in a power hardware-in-the-loop testbed that incorporates models of real LV distribution grids. Furthermore, the algorithm's capabilities are examined through eight scenarios, out of which four focus on the uncertainties of the input data and two address the engagement of extra grid capacity restrictions. The results demonstrate that the SC algorithm adequately lowers the EV charging cost while fulfilling the charging demand, and substantially reduces the peak power as well as the overloading duration, even when faced with input data uncertainty. The additional grid restrictions in place are proven to improve peak demand reduction and overloading mitigation further. Finally, the limitations and potentials of the developed algorithm are scrutinized.","Costs; Distribution Grid; Electric Vehicle; Hardware-In-the-Loop; Hardware-in-the-loop simulation; Optimization; Protocols; Real-time systems; Smart charging; Software algorithms","en","journal article","","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:c392018e-03aa-4706-bc85-3eaefd1f10e7","http://resolver.tudelft.nl/uuid:c392018e-03aa-4706-bc85-3eaefd1f10e7","Human Merging Behavior in a Coupled Driving Simulator: How Do We Resolve Conflicts?","Siebinga, O. (TU Delft Human-Robot Interaction); Zgonnikov, A. (TU Delft Human-Robot Interaction); Abbink, D.A. (TU Delft Human-Robot Interaction; TU Delft Human-Centred Artificial Intelligence)","","2024","Traffic interactions between merging and highway vehicles are a major topic of research, yielding many empirical studies and models of driver behaviour. Most of these studies on merging use naturalistic data. Although this provides insight into human gap acceptance and traffic flow effects, it obscures the operational inputs of interacting drivers. Besides that, researchers have no control over the vehicle kinematics (i.e., positions and velocities) at the start of the interactions. Therefore the relationship between initial kinematics and the outcome of the interaction is difficult to investigate. To address these gaps, we conducted an experiment in a coupled driving simulator with a simplified, top-down view, merging scenario with two vehicles. We found that kinematics can explain the outcome (i.e., which driver merges first) and the duration of the merging conflict. Furthermore, our results show that drivers use key decision moments combined with constant acceleration inputs (intermittent piecewise-constant control) during merging. This indicates that they do not continuously optimise their expected utility. Therefore, these results advocate the development of interaction models based on intermittent piecewise-constant control. We hope our work can contribute to this development and to the fundamental knowledge of interactive driver behaviour.","Data models; Games; Kinematics; Measurement; Merging; Vehicles; Visualization","en","journal article","","","","","","","","","","","Human-Robot Interaction","","",""
"uuid:537e7f7c-4208-41bd-8cd8-01174a7798ab","http://resolver.tudelft.nl/uuid:537e7f7c-4208-41bd-8cd8-01174a7798ab","Statistical Modeling of Polarimetric RCS of Road Surfaces for Scattering Simulation and Optimal Antenna Polarization Determination","Bouwmeester, W. (TU Delft Microwave Sensing, Signals & Systems); Fioranelli, F. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2024","Incoherent backscattering of mm-waves from natural rough surfaces is considered. A novel method is proposed to determine the statistical properties of surface scattering from range profile measurements. The method is based on modeling the road surface as a grid of uncorrelated scattering elements, described by normalized scattering matrices. Using this model, expressions are derived to estimate the mean value and covariance matrix of surface scattering from measurement data. This procedure is then applied to measurement data of four road surface types, namely: 1) dry asphalt, 2) wet asphalt, 3) asphalt covered by basalt gravel, and 4) old asphalt. Using the derived statistical normalized radar cross-section models, two novel applications are proposed. First, a procedure for synthesizing/simulating surface clutter is proposed. This procedure is subsequently used to simulate received power from surfaces comprising patches of one or multiple road surface conditions. Excellent agreement between simulation and measurement results is demonstrated. Second, a method for determining the optimal polarization of the electromagnetic sensing waves used in a single-polarized radar system is proposed. This method is based on factorizing the antenna polarization vector into two bounded parameters, allowing for numerical evaluation of the minima and maxima for targets with a specified scattering matrix. This method is further extended to work with statistical descriptions of scattering matrices by means of Monte Carlo simulations.","automotive; polarimetry; radar; radar cross section (RSC); simulation; surface clutter","en","journal article","","","","","","","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:c7142c8f-f8ac-421e-a6f5-cbcc6abc72cf","http://resolver.tudelft.nl/uuid:c7142c8f-f8ac-421e-a6f5-cbcc6abc72cf","Haptic Shared Control for Dissipating Phantom Traffic Jams","Koerten, K.O. (TU Delft Human-Robot Interaction); Abbink, D.A. (TU Delft Human-Robot Interaction; TU Delft Human-Centred Artificial Intelligence); Zgonnikov, A. (TU Delft Human-Robot Interaction)","","2024","Traffic jams occurring on highways cause increased travel time as well as increased fuel consumption and collisions. So-called phantom traffic jams are traffic jams that do not have a clear cause, such as a merging on-ramp or an accident. Phantom traffic jams make up 50% of all traffic jams and result from instabilities in the traffic flow that are caused by human driving behavior. Automating the longitudinal vehicle motion of only 5% of all cars in the flow can dissipate phantom traffic jams. However, driving automation introduces safety issues when human drivers need to take over the control from the automation. We investigated whether phantom traffic jams can be dissolved using haptic shared control. This keeps humans in the loop and thus bypasses the problem of humans’ limited capacity to take over control, while benefiting from most advantages of automation. In an experiment with 24 participants in a driving simulator, we tested the effect of haptic shared control on the dynamics of traffic flow and compared it with manual control and full automation. We also investigated the effect of two control types on participants’ behavior during simulated silent automation failures. Results show that haptic shared control can help dissipating phantom traffic jams better than fully manual control but worse than full automation. We also found that haptic shared control reduces the occurrence of unsafe situations caused by silent automation failures compared to full automation. Our results suggest that haptic shared control can dissipate phantom traffic jams while preventing safety risks associated with full automation.","Active pedals; Automation; Automobiles; Behavioral sciences; driving simulator; Haptic interfaces; haptic shared control; longitudinal vehicle motion; phantom traffic jams; Phantoms; Roads; silent automation failure; Vehicles","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-10","","","Human-Robot Interaction","","",""
"uuid:fe8625a2-3fe6-4dd8-8b94-cc74b18aca59","http://resolver.tudelft.nl/uuid:fe8625a2-3fe6-4dd8-8b94-cc74b18aca59","Ambient air pollution and consumer spending: Evidence from Spain","Brandt, John (World Resources Institute); Goyal, N. (TU Delft Organisation & Governance); Moroney, Matthew (Raise Green, Inc.); Janaskie, Sophie (Stanford University); Hsu, Angel (University of North Carolina at Chapel Hill)","","2024","Research on the economic burden of air pollution has focused primarily on its macroeconomic impact. However, as some studies have found that air pollution can lead to avoidance behavior–for example, reducing the time spent outdoors–we hypothesize that it can also influence consumer spending activity. We combine high frequency data on ozone and fine particulate pollution with daily consumer spending in brick-and-mortar retail in 129 postal codes in Spain during 2014 to estimate the association between the two. Using a linear fixed effects model, we find that a 1-standard deviation increase in ozone concentration (20.97 μg/m3) is associated with 3.9 percent decrease in consumer spending (95% CI: -0.066, -0.012; p<0.01). The association of fine particulate matter with consumer spending is, however, not statistically significant (β: 0.005; 95% CI: -0.009, 0.018; p>0.10). Further, we do not observe a sufficiently strong bounce-back in consumer spending in the day–or even the week–following higher ozone concentration. Also, we find that the relationship between ozone concentration and consumer spending is heterogeneous, with those aged below 25 and those aged 45 or above exhibiting stronger negative association. This research informs policymakers about a plausibly unaccounted cost of ambient air pollution, even at concentrations lower than the WHO air quality guideline for short-term exposure.","","en","journal article","","","","","","","","","","","Organisation & Governance","","",""
"uuid:00c1faa5-790b-4540-b7e3-ea2eb456faf7","http://resolver.tudelft.nl/uuid:00c1faa5-790b-4540-b7e3-ea2eb456faf7","On the importance of data encoding in quantum Boltzmann methods","Schalkers, M.A. (TU Delft Numerical Analysis); Möller, M. (TU Delft Numerical Analysis)","","2024","In recent years, quantum Boltzmann methods have gained more and more interest as they might provide a viable path toward solving fluid dynamics problems on quantum computers once this emerging compute technology has matured and fault-tolerant many-qubit systems become available. The major challenge in developing a start-to-end quantum algorithm for the Boltzmann equation consists in encoding relevant data efficiently in quantum bits (qubits) and formulating the streaming, collision and reflection steps as one comprehensive unitary operation. The current literature on quantum Boltzmann methods mostly proposes data encodings and quantum primitives for individual phases of the pipeline, assuming that they can be combined to a full algorithm. In this paper, we disprove this assumption by showing that for encodings commonly discussed in the literature, either the collision or the streaming step cannot be unitary. Building on this landmark result, we propose a novel encoding in which the number of qubits used to encode the velocity depends on the number of time steps one wishes to simulate, with the upper bound depending on the total number of grid points. In light of the non-unitarity result established for existing encodings, our encoding method is to the best of our knowledge the only one currently known that can be used for a start-to-end quantum Boltzmann solver where both the collision and the streaming step are implemented as a unitary operation.","Computational fluid dynamics; Lattice Boltzmann; Quantum data encoding; Quantum fluid dynamics; Quantum lattice Boltzmann","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Numerical Analysis","","",""
"uuid:b41ebaa1-d116-4b56-91e3-0feba728ec51","http://resolver.tudelft.nl/uuid:b41ebaa1-d116-4b56-91e3-0feba728ec51","Four-dimensional computational ultrasound imaging of brain hemodynamics","Brown, Michael D. (Erasmus MC; University College London (UCL)); Generowicz, Bastian S. (Erasmus MC); Dijkhuizen, Stephanie (Erasmus MC); Koekkoek, Sebastiaan K.E. (Erasmus MC); Strydis, C. (TU Delft Computer Engineering; Erasmus MC); Bosch, Johannes G. (Erasmus MC); Arvanitis, Petros (Erasmus MC); Springeling, Geert (Erasmus MC); Leus, G.J.T. (TU Delft Signal Processing Systems); De Zeeuw, Chris I. (Erasmus MC; Royal Dutch Academy for Arts and Sciences, Amsterdam); Kruizinga, P. (TU Delft Signal Processing Systems; Erasmus MC)","","2024","Four-dimensional ultrasound imaging of complex biological systems such as the brain is technically challenging because of the spatiotemporal sampling requirements. We present computational ultrasound imaging (cUSi), an imaging method that uses complex ultrasound fields that can be generated with simple hardware and a physical wave prediction model to alleviate the sampling constraints. cUSi allows for high-resolution four-dimensional imaging of brain hemodynamics in awake and anesthetized mice.","","en","journal article","","","","","","","","","","","Computer Engineering","","",""
"uuid:af987156-1e5c-46ac-a9f0-6f26d284c570","http://resolver.tudelft.nl/uuid:af987156-1e5c-46ac-a9f0-6f26d284c570","Comprehensive validation of three-dimensional finite element modelling of wheel-rail high-frequency interaction via the V-Track test rig","Zhang, P. (TU Delft Railway Engineering); He, C. (TU Delft Railway Engineering); Shen, C. (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","","2024","Wheel-rail high-frequency interaction is closely related to the formation of railway short-wave defects. Finite element (FE) method has been widely used to simulate wheel-rail dynamic systems, but its validity in modelling high-frequency interaction has not been fully demonstrated in three dimensions (3D). This work aims at comprehensively validating the 3D FE modelling of wheel-rail high-frequency interaction using a downscale V-Track test rig. First, the FE model of the V-Track is developed that comprehensively includes the 3D track elasticity. The simulated track dynamic behaviours are validated against hammer tests, and the major vibration modes are analyzed employing modal analysis. Afterwards, the simulate wheel-rail dynamic responses are comprehensively compared with measurement results up to 10 kHz. Their characteristic frequencies are identified and correlated to the eigenmodes of the vehicle-track system. The results indicate that the proposed 3D FE model is capable of comprehensively and accurately simulating the 3D track dynamics and wheel-rail dynamic interaction of the V-Track up to 10 kHz. Rail vibrations dominate the wheel-rail dynamic contact within 10 kHz, while the wheel vibrations play an increasingly important role at higher frequencies and become decisive near the wheel eigenmode frequencies. The V-Track overall achieves dynamic similarity to the real vehicle-track system.","3D finite element modelling; comprehensive validation; high-frequency interaction; V-Track test rig; vibration modes; Wheel-rail dynamic system","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:f9fa681b-aabc-46d2-9e6e-3a8ef4e2e932","http://resolver.tudelft.nl/uuid:f9fa681b-aabc-46d2-9e6e-3a8ef4e2e932","Service Design as Formgiving: Breaking Free from the Marketing-Dominant Logic","Secomandi, Fernando (TU Delft Creative Processes)","","2024","","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-01","","","Creative Processes","","",""
"uuid:cb912bca-7368-44cd-ae61-a8784be11712","http://resolver.tudelft.nl/uuid:cb912bca-7368-44cd-ae61-a8784be11712","Research Avenues Supporting Embodied Cognition in Learning and Instruction","Castro-Alonso, Juan C. (University of Birmingham); Ayres, Paul (University of New South Wales); Zhang, S. (TU Delft Statistics; Erasmus Universiteit Rotterdam); de Koning, Björn B. (Erasmus Universiteit Rotterdam); Paas, Fred (Erasmus Universiteit Rotterdam; University of Wollongong)","","2024","Research on embodied cognition acknowledges that cognitive processing is tightly coupled with bodily activities and the environment. An important implication for education is that learning can be enhanced when the brain, body, and environment mutually influence each other, such as when making or observing human actions, especially those involving hand gestures and manipulation of objects. In this narrative review article, we describe the evidence from six research avenues that can help explain why embodied cognition can enhance learning and instruction. Through the exploration of these six interconnected research pathways, we aim to make a significant contribution by proposing innovative directions for learning and instruction research, all rooted in the principles of embodied cognition. We establish a direct link between the six research pathways and embodied phenomena, both in the contexts of making and observing human movements. When making human movements, the research avenues explaining the learning benefits due to these movements are physical activity, generative learning, and offloaded cognition. When observing human movements, the avenues researching these phenomena are specialized processor and signaling. Lastly, the research avenue social cognition is integral to both making and observing human movements. With originality in focus, we also include research that has not been traditionally associated with embodied cognition or embodiment. This article offers comprehensive discussions, substantiated with evidence and influencing features, for each of these research avenues. We conclude by outlining the implications of these findings for instruction and charting potential directions for future investigation.","Embodied cognition; Embodiment and education; Gesture and gesturing; Human body action and hand movement; Object manipulation and model","en","review","","","","","","","","","","","Statistics","","",""
"uuid:41c390b0-ee80-44b5-ba22-e3eb4e20ebb5","http://resolver.tudelft.nl/uuid:41c390b0-ee80-44b5-ba22-e3eb4e20ebb5","MoO3 nanowire growth on VO2/WO3 for thermochromic applications","Houimi, Amina (Necmettin Erbakan University; Bilkent University); Basyooni, Mohamed A. (TU Delft Dynamics of Micro and Nano Systems; Necmettin Erbakan University; National Research Institute of Astronomy and Geophysics); Yılmaz, Mücahit (Necmettin Erbakan University); Eker, Yasin Ramazan (Necmettin Erbakan University)","","2024","This study explores the structural, electronic, and optical properties of sandwich-structured thin films composed of WO3, MoWO3, and MoO3 as window layers on VO2/WO3 via a physical vapor deposition method. Morphological analysis demonstrates the evolution of distinct nanowires, offering insights into the lattice strain of the VO2 layer toward high-performance thermochromatic devices. Temperature-dependent sheet resistivity is investigated, showcasing significant improvements in conductivity for samples with MoO3 as a window layer. The electrical and optical properties of the MoO3/VO2/WO3 device showed a phase transition temperature (Tc) of 36.8 °C, a transmittance luminous (Tlum) of 54.57%, and a solar modulation ability (ΔTsol) of 12.43. This comprehensive analysis contributes to understanding the growth of nanowires on multi-layered thin films, offering valuable insights into potential applications in bright windows.","","en","journal article","","","","","","","","","","","Dynamics of Micro and Nano Systems","","",""
"uuid:0465a210-8c78-487d-8964-26ac84781ec9","http://resolver.tudelft.nl/uuid:0465a210-8c78-487d-8964-26ac84781ec9","Experimental comparative study on thermal performance of latent heat storage tanks with pin, perforated, and rectangular fins at different orientations","Safari, Vahid (Carlos III University of Madrid); Kamkari, Babak (Ulster University); Hewitt, Neil (Ulster University); Hooman, K. (TU Delft Heat Transformation Technology)","","2024","The low thermal conductivity of phase change materials (PCMs) has limited their widespread use in practical applications. In the present study, different fin structures, namely, rectangular, perforated, and pin were examined to analyze the thermal performance of the melting process in rectangular latent heat storage tanks. Experiments were performed at both horizontal and vertical orientations to evaluate the effectiveness of different fin configurations. Visual observation of the phase change evolution at different time intervals was enabled through a transparent plexiglass shell. Instantaneous heat transfer rate and energy storage were measured using thermocouple readings and melting photographs. The results show that the maximum heat transfer coefficient between the heated wall and PCM is obtained by the pin-finned tank followed by perforated and rectangular-finned tanks. This thermal behavior is justified by the intensification of the upward convection flows through the voids provided by pin fins or perforated fins. Although the rectangular fin structure has the lowest convective heat transfer coefficient, its heat transfer rate is slightly higher than the other structures due to its larger heat transfer area. At a wall temperature of 70℃, the convective heat transfer coefficient and heat transfer rate obtained by the pin fin configuration are respectively 25% higher and 4% less than those of the rectangular fin. It reveals that the pin fin structure provides the most effective heat transfer area compared to its counterparts which have a significantly larger fin volume. In addition, it was found that regardless of the fin configuration, the melting rate in the horizontal tank was significantly higher than in the vertical tank due to the formation of more vortical flow structures within the molten PCM. The melting time in the unfinned horizontal tank was less than those of the vertical finned tanks implying that the tank orientation should be well-chosen to minimize the melting time along with adding fins of various configurations.","Heat transfer; Latent heat storage (LHS); Melting; Perforated fin; Phase change materials (PCM); Pin fin; Rectangular fin","en","journal article","","","","","","","","","","","Heat Transformation Technology","","",""
"uuid:d2e4a0d0-55d6-4d3a-a907-86aea7b9bf70","http://resolver.tudelft.nl/uuid:d2e4a0d0-55d6-4d3a-a907-86aea7b9bf70","Using System Dynamics to Support Strategic Digitalization Decisions","Kaya, H.D. (TU Delft Organisation & Governance; Middle East Technical University); Dikmen, Irem (University of Reading)","","2024","Although digitalization has become a prospect that is counted on for many problems in the construction industry, there have been limited attempts at exploring decision-making processes in construction firms concerning the integration of digital technologies and impacts beyond the projects. In this research, the system dynamics (SD) approach was proposed to investigate digitalization as a strategic decision considering the inherent relationships between project company and business levels. The SD model was conceptualized, formulated, and tested by conducting a demonstrative case study within a modular construction company. Conforming to the strategic priorities of the case company, business process engineering principles were adopted to model the existing practices and assess the impacts of implementing digital technologies such as building information modeling (BIM), enterprise resource planning (ERP), and radio frequency identification (RFID) at different maturity levels. The simulation tests revealed that the impacts of technologies are influenced by the internal dynamics of projects and company competencies as well as external uncertainties. The SD model has the potential to improve strategic decision-making by anticipating the causalities and feedback between the decisions and consequences of technology integration. The findings and model development steps proposed in this paper can be used by other companies that aim to make process improvements with digital technologies as well as researchers exploring the implications of digitalization in construction considering competencies and uncertainties.","Digitalization; Strategic decision-making; System dynamics modeling","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-18","","","Organisation & Governance","","",""
"uuid:0e95f2d6-14eb-425c-8826-a1665c214531","http://resolver.tudelft.nl/uuid:0e95f2d6-14eb-425c-8826-a1665c214531","Living labs for user empowerment and value delivery in social housing upgrading processes","Kowaltowski, D.C.C.K. (University of Campinas); Gomes da Silva, V. (University of Campinas); van Oel, C.J. (TU Delft Design & Construction Management); Granja, A.D. (University of Campinas); Muianga, E.A.D. (University of Campinas); Kabisch, S. (Helmholtz Centre for Environmental Research - UFZ); De Carvalho Moreira, D. (University of Campinas); Koolwijk, J.S.J. (TU Delft Design & Construction Management); Pößneck, J. (Helmholtz Centre for Environmental Research - UFZ)","","2024","Upgrading existing social housing (SH) requires user-centred participatory processes to promote values. Comparative case studies in Brazil, Germany, the Netherlands, and the UK are presented. Living Labs (LLs) were conducted for the delivery of user values and to promote an informed decision-making process. Tools and LL activities were tested to engage stakeholders in the upgrading process, support the co-creation of solutions and address social and societal challenges. The main research aims were to facilitate SH upgrading processes focusing on the delivery of value for users, achieving end-user empowerment, as well as assessing participatory decision-making through LLs. Research goals were achieved in each case study setting. The evaluation of specific cases informed a conceptual framework and guidelines to facilitate upgrading through LLs in varied SH landscapes.","user-centred design; participatory design; case studies; living labs; social housing upgrading","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:b917963e-f07c-420a-b163-47c4703d73ea","http://resolver.tudelft.nl/uuid:b917963e-f07c-420a-b163-47c4703d73ea","Changes in Health-Related Quality of Life following Surgery in Patients with High-Grade Extremity Soft-Tissue Sarcoma: A Prospective Longitudinal Study","Kruiswijk, Anouk (Leiden University Medical Center); Sande, MAJ van de (Leiden University Medical Center); Verhoef, Cornelis (Erasmus MC); Schrage, Yvonne M. (Netherlands Cancer Institute); Haas, Rick L (Netherlands Cancer Institute; Leiden University Medical Center); Bemelmans, Marc H. A. (Maastricht University Medical Center); van Ginkel, Robert J. (University Medical Center Groningen); Bonenkamp, Johannes J. (Radboud University Medical Center); Witkamp, Arjen J. (University Medical Center Utrecht); van den Akker-van Marle, M. Elske (Leiden University Medical Center); Marang-van de Mheen, P.J. (TU Delft Safety and Security Science); van Bodegom-Vos, Leti (Leiden University Medical Center)","","2024","Introduction: Changes in health-related quality of life (HRQoL) during the diagnostic and treatment trajectory of high-grade extremity soft-tissue sarcoma (eSTS) has rarely been investigated for adults (18–65 y) and the elderly (aged ≥65 y), despite a potential variation in challenges from diverse levels of physical, social, or work-related activities. This study assesses HRQoL from time of diagnosis to one year thereafter among adults and the elderly with eSTS. Methods: HRQoL of participants from the VALUE-PERSARC trial (n = 97) was assessed at diagnosis and 3, 6 and 12 months thereafter, utilizing the PROMIS Global Health (GH), PROMIS Physical Function (PF) and EQ-5D-5L. Results: Over time, similar patterns were observed in all HRQoL measures, i.e., lower HRQoL scores than the Dutch population at baseline (PROMIS-PF:46.8, PROMIS GH-Mental:47.3, GH-Physical:46.2, EQ-5D-5L:0.76, EQ-VAS:72.6), a decrease at 3 months, followed by an upward trend to reach similar scores as the general population at 12 months (PROMIS-PF:49.9, PROMIS GH-Physical:50.1, EQ-5D-5L:0.84, EQ-VAS:81.5), except for the PROMIS GH-Mental (47.5), where scores remained lower than the general population mean (T = 50). Except for the PROMIS-PF, no age-related differences were observed. Conclusions: On average, eSTS patients recover well physically from surgery, yet the mental component demonstrates no progression, irrespective of age. These results underscore the importance of comprehensive care addressing both physical and mental health.","soft-tissue sarcoma; extremity; Health-related quality of life; physical functioning; mental health","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:46a223bf-9b97-420b-86f3-bb96d2add9fd","http://resolver.tudelft.nl/uuid:46a223bf-9b97-420b-86f3-bb96d2add9fd","An interface-enriched generalized finite element method for the analysis and topology optimization of 2-D electromagnetic problems","van Bergen, Steven (Student TU Delft); Norte, R.A. (TU Delft QN/Groeblacher Lab; TU Delft Dynamics of Micro and Nano Systems; Kavli institute of nanoscience Delft); Aragon, A.M. (TU Delft Computational Design and Mechanics)","","2024","The computational analysis of nanophotonic devices is usually carried out via the standard finite element method (FEM). However, FEM requires meshes that are fitted to the devices’ boundaries, so making changes to the geometry (and thus the mesh) results in an inefficient process at best. Such an approach is therefore at odds when conducting design, which requires the analysis of multiple device geometries until reaching a satisfactory solution. Computational design tools such as topology optimization are often used, but the use of density-based representations of geometry inevitably leads to other issues—e.g., pixelized fuzzy boundaries with “gray material” (that does not correspond to dielectric nor vacuum) have an adverse effect on the devices’ interaction with electromagnetic waves. In this paper we propose an interface-enriched generalized finite element method (IGFEM) for the analysis of two-dimensional electromagnetic scattering and eigenvalue problems. IGFEM enables the use of finite element meshes that are completely decoupled from the problem's geometry. The analysis procedure is further coupled to a level set description of topology, resulting in a versatile enriched approach to topology optimization; this level set-based interface-enriched topology optimization procedure is devoid of the issues mentioned above regarding density-based methods, and yields crisp “black-and-white” designs that are devoid of jagged fuzzy edges. We first demonstrate that the analysis procedure achieves the same convergence rate as that of standard FEM using geometry-fitted meshes. We then compare the convergence properties of IGFEM with Nitsche's method on a problem containing an embedded straight interface. Finally, we conduct topology optimization for designing both a 2-D metalens and a 2-D reflector, maximizing their ability to focus light onto a target point.","Electromagnetics; Enriched finite element analysis; Interface-enriched generalized finite element method (IGFEM); Level set method; Topology optimization","en","journal article","","","","","","","","","","","QN/Groeblacher Lab","","",""
"uuid:3d0c1cf8-8e92-459a-8f6c-01f204cb1cdf","http://resolver.tudelft.nl/uuid:3d0c1cf8-8e92-459a-8f6c-01f204cb1cdf","Enzyme engineering for biocatalysis","Paul, C.E. (TU Delft BT/Biocatalysis); Hanefeld, U. (TU Delft BT/Biocatalysis); Hollmann, F. (TU Delft BT/Biocatalysis); Qu, Ge (Chinese Academy of Sciences); Yuan, Bo (Chinese Academy of Sciences); Sun, Zhoutong (Chinese Academy of Sciences)","","2024","Contemporary Biocatalysis heavily relies on enzyme engineering as natural enzymes frequently lack the requisite attributes for effective organic synthesis. The inherent limitations in stability, catalytic activity, and selectivity of wild-type enzymes often hinder their suitability for chemical synthesis. Over the past 25 years, there has been an unprecedented advancement in protein engineering tools, empowering enzymologists to customise enzymes to precisely meet the demands of organic synthesis. In this discussion, we delineate some of the most crucial techniques in enzyme engineering and their significance in facilitating chemical synthesis.","Biocatalysis; Directed evolution; Iterative saturation mutagenesis; Semi-rational design","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:be47f23e-7857-425b-bc1f-a93f0e1e0c75","http://resolver.tudelft.nl/uuid:be47f23e-7857-425b-bc1f-a93f0e1e0c75","Integrating geospatial, remote sensing, and machine learning for climate-induced forest fire susceptibility mapping in Similipal Tiger Reserve, India","Singha, Chiranjit (University of Visva-Bharati); Swain, Kishore Chandra (University of Visva-Bharati); Moghimi, Armin (Leibniz Universität); Foroughnia, Fatemeh (TU Delft Geo-engineering); Swain, Sanjay Kumar (University of Visva-Bharati)","","2024","Accurately assessing forest fire susceptibility (FFS) in the Similipal Tiger Reserve (STR) is essential for biodiversity conservation, climate change mitigation, and community safety. Most existing studies have primarily focused on climatic and topographical factors, while this research expands the scope by employing a synergistic approach that integrates geographical information systems (GIS), remote sensing (RS), and machine learning (ML) methodologies for identifying and assessing forest fire-prone areas in the STR and their vulnerability to climate change. To achieve this, the study employed a comprehensive dataset of forty-four influencing factors, including topographic, climate-hydrologic, forest health, vegetation indices, radar features, and anthropogenic interference, into ten ML models: neural net (nnet), AdaBag, Extreme Gradient Boosting (XGBTree), Gradient Boosting Machine (GBM), Random Forest (RF), and its hybrid variants with differential evolution algorithm (RF-DEA), Gravitational Based Search (RF-GBS), Grey Wolf Optimization (RF-GWO), Particle Swarm Optimization (RF-PSO), and genetic algorithm (RF-GA). The study revealed high FFS in both the northern and southern portions of the study area, with the nnet and RF-PSO models demonstrating susceptibility percentages of 12.44% and 12.89%, respectively. Conversely, very low FFS zones consistently displayed susceptibility scores of approximately 23.41% and 18.57% for the nnet and RF-PSO models. The robust mapping methodology was validated by impressive AUROC (>0.88) and kappa coefficient (>0.62) scores across all ML validation metrics. Future climate models (ssp245 and ssp585, 2022–2100) indicated high FFS zones along the northern and southern edges of the STR, with the central zone categorized from low to very low susceptibility. Boruta analysis identified actual evapotranspiration (AET) and relative humidity as key factors influencing forest fire ignition. SHAP evaluation reinforced the influence of these factors on FFS, while also highlighting the significant role of distance to road, distance to settlement, dNBR, slope, and humidity in prediction accuracy. These results emphasize the critical importance of the proposed approach for forest fire mapping and provide invaluable insights for firefighting teams, forest management, planning, and qualification strategies to address future fire sustainability.","Boruta-SHAP; Forest fire; Machine learning; Risk map; Susceptibility map","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:6621e1be-439d-45dd-84bb-89aac5fb5775","http://resolver.tudelft.nl/uuid:6621e1be-439d-45dd-84bb-89aac5fb5775","Noninvasive Advanced Cardiovascular Magnetic Resonance-Derived Fontan Hemodynamics Are Associated With Reduced Kidney Function But Not Albuminuria","Van den Eynde, Jef (Leiden University Medical Center); Westenberg, Jos J.M. (Leiden University Medical Center); Hazekamp, Mark G. (Leiden University Medical Center); Lamb, Hildo J. (Leiden University Medical Center); Jongbloed, Monique R.M. (Leiden University Medical Center); Wentzel, Jolanda J. (Erasmus MC); Kenjeres, S. (TU Delft ChemE/Transport Phenomena); Dekkers, Ilona A. (Leiden University Medical Center); Rijnberg, F.M. (TU Delft ChemE/Transport Phenomena; Leiden University Medical Center)","","2024","BACKGROUND: Kidney disease is the most important predictor of death in patients with a Fontan circulation, yet its clinical and hemodynamic correlates have not been well established. METHODS AND RESULTS: A total of 53 ambulatory patients with a Fontan circulation (median age, 16.2 years, 52.8% male patients) underwent advanced cardiovascular magnetic resonance assessment, including 4-dimensional flow imaging and computational fluid dynamics. Estimated glomerular filtration rate (eGFR) <90 mL/min per 1.73 m2 was observed in 20.8% and albumin-to-creatinine ratio >3 mg/mmol in 39.6%. The average eGFR decline rate was -1.83 mL/min per 1.73 m2 per year (95% CI, -2.67 to -0.99; P<0.001). Lower eGFR was associated with older age, larger body surface area at examination, longer time since Fontan procedure, and lower systemic ventricular ejection fraction. Higher albumin-to-creatinine ratio was associated with absence of fenestration at the Fontan operation, and older age and lower systemic ventricular ejection fraction at the assessment. Lower cross-sectional area of the Fontan conduit indexed to flow (r=0.32, P=0.038), higher inferior vena cava-conduit velocity mismatch factor (r=-0.35, P=0.022), higher kinetic energy indexed to flow in the total cavopulmonary connection (r=-0.59, P=0.005), and higher total cavopulmonary connection resistance (r=-0.42, P=0.005 at rest; r=-0.43, P=0.004 during exercise) were all associated with lower eGFR but not with albuminuria. CONCLUSIONS: Kidney dysfunction and albuminuria are common among clinically well adolescents and young adults with a Fontan circulation. Advanced cardiovascular magnetic resonance-derived metrics indicative of declining Fontan hemodynamics are associated with eGFR and might serve as targets to improve kidney health. Albuminuria might be driven by other factors that need further investigation.","albuminuria; chronic kidney disease; computational fluid dynamics; Fontan; hemodynamics; kidney function; magnetic resonance imaging","en","journal article","","","","","","","","","","","ChemE/Transport Phenomena","","",""
"uuid:827b99c0-a7cf-4280-ba3b-0a1f6a7dc1ff","http://resolver.tudelft.nl/uuid:827b99c0-a7cf-4280-ba3b-0a1f6a7dc1ff","Improving Traffic Efficiency With Lane Guidance Based on Desired Speeds","Mahajan, N. (TU Delft Transport and Planning); Hegyi, A. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning)","","2024","Drivers initiate a discretionary lane change when they perceive an anticipated improvement in their own driving condition from moving to another lane. However, such a lane change can slow down other vehicles on the target lane, and even worse initiate a disturbance. In this work, we argue that the blocking effect triggered by individual lane changes results from the heterogeneity in the desired speeds of vehicles, and thus using desired speed information of vehicles when regulating lane-changing decisions can improve traffic efficiency. In doing so, our work also exemplifies the usefulness of incorporating user preferences into control decisions. The proposed lane guidance system uses an optimization-based approach to update the target range of desired speeds on each lane in real time, and accordingly recommends individual lane changes. The control system coordinates the lane-changing decisions at the link level, for which the road stretch is subdivided into multiple sections that are controlled independently. We evaluate the performance of the lane guidance system in micro-simulation, for different network demands and desired speed distributions. The results highlight that the proposed approach utilizing the desired speed preferences of drivers results in positive efficiency gains for most traffic compositions in free flow. Moreover, the highest gains are expected in medium to high demand, and when the traffic composition includes a higher proportion of vehicles desiring higher speeds. The gains also increase when the desired speeds of vehicles that want to drive fast and those that want to drive slower are more separated.","cooperative lane-changing; desired speeds; Lane guidance; Merging; Optimization; Real-time systems; Roads; Traffic control; traffic efficiency; user preferences in traffic control; Vehicle dynamics; Vehicles","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:77feeed6-bb9a-4a2f-be1a-8b6846b0dd20","http://resolver.tudelft.nl/uuid:77feeed6-bb9a-4a2f-be1a-8b6846b0dd20","Functional analysis of web-based GIS tools for environmental justice assessment of transportation projects","Spriggs, A.M.S. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; University of Missouri); Rotman, Robin (University of Missouri); Trauth, Kathleen (University of Missouri)","","2024","Environmental justice – the concept that environmental amenities and burdens should be shared equitably among all races and socioeconomic classes – has gained diplomatic traction internationally, and political traction domestically in the United States, in recent years. In this paper, we focus on developing federal policy relevant to transportation project planning and operation in the U.S.; however, these developments reflect international issues of inequity associated with climate change and environmental burdens. First, we provide an overview of federal policy initiatives related to environmental justice, including President Biden's Justice40 initiative. Then, we examine the U.S. National Environmental Policy Act (NEPA) as a potential avenue for mandating environmental justice assessment in the transportation industry, through the lenses of both procedural and distributive justice. Finally, we review several publicly available online Geographical Information System (GIS) tools that were recently developed for purposes of expanding public and governmental understanding of environmental justice challenges, and provide decision support for users to incorporate these tools into the environmental impact assessment process for transportation projects.","Environmental justice; Geographic information systems; Global Environmental Governance; Infrastructure; National Environmental Policy Act (NEPA); Transportation","en","journal article","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:45d8e231-e86e-4e4d-acb3-dc2eec212241","http://resolver.tudelft.nl/uuid:45d8e231-e86e-4e4d-acb3-dc2eec212241","Monitoring the impact of COVID-19 on the travel behavior of train travelers in the Netherlands","Ton, D. (TU Delft Transport and Planning; NS Stations); De Bruyn, Menno (N.V. Nederlandse Spoorwegen); Van Hagen, Mark (N.V. Nederlandse Spoorwegen); Duives, D.C. (TU Delft Transport and Planning); van Oort, N. (TU Delft Transport and Planning)","","2024","Mobility patterns and transport systems have been heavily impacted due to the COVID-19 pandemic. Public transport is impacted heavily, as governments worldwide advised against using it. This paper presents the data collection effort initiated by NS (Dutch Railways) and Delft University of Technology to capture changes in travel behavior, attitudes and intentions related to the COVID-19 pandemic among Dutch train travelers. The survey set-up, data collection process, data validation and potential of the dataset are discussed. The data collection effort proves to be a valuable longitudinal data set that is ground for many research opportunities and policy insights.","COVID-19; longitudinal data collection; survey design; train travelers; travel behavior","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:f7174a5b-00c4-4479-9620-6dd838d62490","http://resolver.tudelft.nl/uuid:f7174a5b-00c4-4479-9620-6dd838d62490","Neural Autoencoder-Based Structure-Preserving Model Order Reduction and Control Design for High-Dimensional Physical Systems","Lepri, M. (University of Pisa; NEC Laboratories Europe); Bacciu, Davide (University of Pisa); Della Santina, C. (TU Delft Learning & Autonomous Control; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR))","","2024","This letter concerns control-oriented and structure-preserving learning of low-dimensional approximations of high-dimensional physical systems, with a focus on mechanical systems. We investigate the integration of neural autoencoders in model order reduction, while at the same time preserving Hamiltonian or Lagrangian structures. We focus on extensively evaluating the considered methodology by performing simulation and control experiments on large mass-spring-damper networks, with hundreds of states. The empirical findings reveal that compressed latent dynamics with less than 5 degrees of freedom can accurately reconstruct the original systems' transient and steady-state behavior with a relative total error of around 4%, while simultaneously accurately reconstructing the total energy. Leveraging this system compression technique, we introduce a model-based controller that exploits the mathematical structure of the compressed model to regulate the configuration of heavily underactuated mechanical systems.","autoencoders; Hamiltonian dynamics; model order reduction","en","journal article","","","","","","","","","","","Learning & Autonomous Control","","",""
"uuid:62205fc4-ab38-49b8-ae91-047740e60497","http://resolver.tudelft.nl/uuid:62205fc4-ab38-49b8-ae91-047740e60497","Scalarizing Multi-Objective Robot Planning Problems Using Weighted Maximization","Wilde, N. (TU Delft Learning & Autonomous Control); Smith, Stephen L. (University of Waterloo); Alonso-Mora, J. (TU Delft Learning & Autonomous Control)","","2024","When designing a motion planner for autonomous robots there are usually multiple objectives to be considered. However, a cost function that yields the desired trade-off between objectives is not easily obtainable. A common technique across many applications is to use a weighted sum of relevant objective functions and then carefully adapt the weights. However, this approach may not find all relevant trade-offs even in simple planning problems. Thus, we study an alternative method based on a weighted maximum of objectives. Such a cost function is more expressive than the weighted sum, and we show how it can be deployed in both continuous-and discrete-space motion planning problems. We propose a novel path planning algorithm for the proposed cost function and establish its correctness, and present heuristic adaptations that yield a practical runtime. In extensive simulation experiments, we demonstrate that the proposed cost function and algorithm are able to find a wider range of trade-offs between objectives (i.e., Pareto-optimal solutions) for various planning problems, showcasing its advantages in practice.","motion and path planning; multi-objective optimization; Optimization and optimal control; task and motion planning","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-23","","","Learning & Autonomous Control","","",""
"uuid:25da3d79-5699-4535-a88c-a9270c8903d1","http://resolver.tudelft.nl/uuid:25da3d79-5699-4535-a88c-a9270c8903d1","Understanding physical distancing compliance behaviour using proximity and survey data: A case study in the Netherlands during the COVID-19 pandemic","van Schaik, L. (TU Delft Transport and Planning); Duives, D.C. (TU Delft Transport and Planning); Hoogendoorn-Lanser, S. (TU Delft Corporate Innovations); Hoekstra, Jan Willem (NME Foundation; ROC Mondriaan); Daamen, W. (TU Delft Transport and Planning); Gavriilidou, A. (TU Delft Transport and Planning); Krishnakumari, P.K. (TU Delft Transport and Planning); Rinaldi, M. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning)","","2024","Physical distancing has been an important asset in limiting the SARS-CoV-2 virus spread during the COVID-19 pandemic. This study aims to assess compliance with physical distancing and to evaluate the combination of observed and self-reported data used. This research shows that it is difficult to operationalize new rules, that context affects compliance, that there needs to be a need for compliance, and that rules require upkeep. From a methodological point of view, this study found that the combined methods provide a comprehensive picture of compliance behaviour, that it is challenging but essential to mitigate response fatigue in long-term monitoring studies, and that it would be interesting in future research to learn how actual behaviour is influenced by personal narratives.","compliance behaviour; COVID-19 pandemic; longitudinal survey; physical distancing; proximity sensing; SARS-CoV-2","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:2cfba3cc-e348-4539-a99b-e691c9a3cf4b","http://resolver.tudelft.nl/uuid:2cfba3cc-e348-4539-a99b-e691c9a3cf4b","Data-driven identification of the spectral operator in AKNS Lax pairs using conserved quantities","de Koster, P.B.J. (TU Delft Team Sander Wahls); Wahls, S. (Karlsruhe Institut für Technologie)","","2024","Lax-integrable partial differential equations (PDEs) can by definition be described through a compatibility condition between two linear operators. These operators are said to form a Lax pair for the PDE, which itself is usually nonlinear. Lax pairs are a very useful tool, but unfortunately finding them is a difficult problem in practice. In this paper, we propose a method that determines the spectral operator of an AKNS-type Lax pair such that the corresponding PDE fits given measurement data as well as possible. The spectral operator then enables practitioners to solve or analyze the underlying PDE using the induced nonlinear Fourier transform. The underlying PDE only has to be approximately Lax-integrable; the method will find the spectral operator that explains the data best. Together with the dispersion relation, the spectral operator of AKNS type completely determines an integrable PDE that approximates the true underlying PDE. We identify the most suitable spectral operator by matching PDE-dependent quantities that should be conserved during evolution. The method is automatic and only requires recordings of solutions at two different values of the evolution variable, which do not have to be close.","AKNS; Forward scattering transform; Identification; Nonlinear Fourier transform","en","journal article","","","","","","","","","","","Team Sander Wahls","","",""
"uuid:421e00ec-e147-41b0-9c3b-2a14cf41c4d6","http://resolver.tudelft.nl/uuid:421e00ec-e147-41b0-9c3b-2a14cf41c4d6","Linear Time-Varying Parameter Estimation: Maximum A Posteriori Approach via Semidefinite Programming","Vakili, S. (TU Delft Team Manuel Mazo Jr); Khosravi, M. (TU Delft Team Khosravi); Mohajerin Esfahani, P. (TU Delft Team Peyman Mohajerin Esfahani); Mazo, M. (TU Delft Team Manuel Mazo Jr)","","2024","We study the problem of identifying a linear time-varying output map from measurements and linear time-varying system states, which are perturbed with Gaussian observation noise and process uncertainty, respectively. Employing a stochastic model as prior knowledge for the parameters of the unknown output map, we reconstruct their estimates from input/output pairs via a Bayesian approach to optimize the posterior probability density of the output map parameters. The resulting problem is a non-convex optimization, for which we propose a tractable linear matrix inequalities approximation to warm-start a first-order subsequent method. The efficacy of our algorithm is shown experimentally against classical Expectation Maximization and Dual Kalman Smoother approaches.","Estimation; identification; linear matrix inequalities; optimization; semidefinite programming","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-25","","","Team Manuel Mazo Jr","","",""
"uuid:b9eaaf41-2b8c-4a68-b8a6-ce7bcc9976d9","http://resolver.tudelft.nl/uuid:b9eaaf41-2b8c-4a68-b8a6-ce7bcc9976d9","Tracking submarine cables in the wild","Livadariu, Ioana (Simula Metropolitan Center for Digital Engineering); Elmokashfi, Ahmed (Simula Metropolitan Center for Digital Engineering); Smaragdakis, G. (TU Delft Cyber Security)","","2024","During the last ten years, thousands of kilometers of submarine cables have been rolled out to connect regions around the globe and improve intercontinental connectivity. However, while it is relatively easy to get information about the frequent roll-outs of these cables, it is challenging to translate these developments into network information to facilitate networking research. For example, announcements for new submarine cables typically mention landing points and not router IP addresses. With this network information, it is easier to assess the impact of a new submarine cable on end-to-end delays in the connecting regions. In this paper, we investigate the necessary and sufficient conditions to translate public announcements for submarine cables to network information that enables networking research on this topic. We also develop and evaluate a methodology to automatically extract IP-level information for deployed submarine cables and assess their impact on end-to-end performance.","","en","journal article","","","","","","","","","","","Cyber Security","","",""
"uuid:bc26ff25-57d4-409f-b6d3-660b1712043d","http://resolver.tudelft.nl/uuid:bc26ff25-57d4-409f-b6d3-660b1712043d","Crocheting Bour’s Minimal Surfaces","Kekkonen, H.N. (TU Delft Delft Institute of Applied Mathematics; TU Delft Statistics)","","2024","Mathematics and crochet might not appear the most likely pairing for most people. However, crocheting is an inherently mathematical process. You can create various shapes using stitches with different heights and increasing or decreasing the number of stitches in certain places. Crochet also makes it possible to create many shapes that are very difficult to make with any other technique. One can crochet shapes such as the Klein bottle and Seifert surfaces of knots in freestyle, without following exact instructions, since these surfaces do not have a strict shape. A Klein bottle can be short and wide or tall and narrow. But there are many surfaces, for example spheres and disks, that have a specific shape. To crochet such models, you need crochet instructions, and to create such instructions, you need a good understanding of the underlying mathematical model.
The idea of knitting or crocheting mathematical or scientific models is not new, though it has not been used very widely. The Scottish chemist Alexander Crum Brown knitted several interlinked surfaces to visualize the ideas presented in the late nineteenth century in his paper “On a Case of Interlacing Surfaces” [2]. Miles Reid wrote a paper on knitting mathematical surfaces in the 1970s [13] that inspired several new patterns, including a Möbius scarf and a Klein bottle. The crocheted hyperbolic surfaces were introduced by Daina Taimina in 1997 [5], and her idea led to a bloom of so-called hyperbolic crochet. A few years after the paper on hyperbolic crochet appeared, Hinke Osinga and Bernd Krauskopf described how to crochet an approximation of the Lorenz manifold [10]. See also [14] for further examples of mathematical crochet.
Both the hyperbolic plane and the Lorenz manifold require precise crochet instructions. The hyperbolic plane has constant negative Gaussian curvature, and so it looks the same at every point. This allows for a rather simple pattern that can be worked in rounds in which after a few setup rounds, every nth stitch is doubled. The Lorenz manifold is a less-regular surface, and it requires a much more complex pattern of stitches. The model is also worked in rounds, but unlike the hyperbolic surface, it requires detailed instructions on when to add or remove stitches. It takes full advantage of the versatility of crocheting, requiring three different types of stitches, which allows different parts of a round to have different heights. In this paper we consider Bour’s minimal surfaces
, which are “crochet symmetric,” allowing for simple crochet instructions (excluding possible intersections) and requiring only one type of stitch, with the added or removed stitches evenly spaced across a round.","","en","journal article","","","","","","","","","","","Statistics","","",""
"uuid:5426d88b-bc77-4e31-9d63-69871c66e506","http://resolver.tudelft.nl/uuid:5426d88b-bc77-4e31-9d63-69871c66e506","Design thinking in medical education to tackle real world healthcare problems: The MasterMinds Challenge","van Velzen, Monique (Leiden University Medical Center); Boru, A. (TU Delft Delft Centre for Entrepreneurship); Sarton, Elise (Leiden University Medical Center); de Beaufort, Arnout Jan (Leiden University Medical Center)","","2024","Educational challenge: Medical education must equip future professionals with the necessary skills to navigate the complex healthcare landscape. Clinical knowledge is essential, and critical and creative thinking skills are vital to meet the challenges of the system. Design thinking offers a structured approach that integrates creativity and innovation, yet its application in medical education is absent. Solution and implementation: The compulsory MasterMinds Challenge course at Leiden University Medical Center utilizes design thinking principles to address real world healthcare challenges. Final-year medical students participated in a two-day program. The course encompassed empathizing with stakeholders, problem definition, ideation, prototyping, and refining solutions. Presentation skills were emphasized, culminating in a symposium where teams showcase their outcomes. Implementation of the MasterMinds Challenge course was successful with 33 sessions delivered to 1217 medical students. Challenges covered various healthcare topics, yielding creative yet practical outcomes. Students appreciate the real world healthcare challenge, team-based approach, and the applicability of design thinking principles. Challenge owners expressed satisfaction with students’ commitment, creativity, and empathizing abilities. Lessons learned and next steps: To further enhance the MasterMinds Challenge course, a more longitudinal format is being designed, enabling greater autonomy and emphasizing the refining and implementation phases. The course can be extended to medical postgraduate professionals and interdisciplinary collaborations, fostering innovative ideas beyond current practices. By developing problem-solving skills, the MasterMinds Challenge course contributes to a future-proof medical education program and prepares students to meet the evolving needs of healthcare.","collaboration; Design thinking; healthcare challenges; medical education","en","journal article","","","","","","","","","","Delft Centre for Entrepreneurship","","","",""
"uuid:e5d2ac53-770d-4186-89f6-f051c03e513d","http://resolver.tudelft.nl/uuid:e5d2ac53-770d-4186-89f6-f051c03e513d","Method for bandgap interpolation of perovskite's spectral complex refractive index","Blom, Y. (TU Delft Photovoltaic Materials and Devices); Vogt, M.R. (TU Delft Photovoltaic Materials and Devices); Isabella, O. (TU Delft Photovoltaic Materials and Devices)","","2024","Lead halide perovskites are a promising class of materials for solar cell applications. The perovskite bandgap depends on the material composition and is highly tunable. Opto-electrical device modelling is commonly used to find the optimum perovskite bandgap that maximizes device efficiency or energy yield, either in single junction or multi-junction configuration. The first step in this calculation is the optical modelling of the spectral absorptance. This requires as input the perovskite's complex refractive index N as a function of wavelength λ. The complex refractive index consists of real part n(λ) and imaginary part k(λ). For the most commonly used perovskites, n and k curves are available from spectroscopic ellipsometry measurements, but usually only for a few discrete bandgap energies. For solar cell optimization, these curves are required for a continuous range of bandgap energies. We introduce new methods for generating the n and k curves for an arbitrary bandgap, based on interpolating measured complex refractive index data. First, different dispersion models (Cody-Lorentz, Ullrich-Lorentz and Forouhi-Bloomer) are used to fit the measured data. Then, a linear regression is applied to the fit parameters with respect to the bandgap energy. From the interpolated parameters, the refractive index curve of perovskite with any desired bandgap energy is finally reconstructed. To validate our method, we compare our results with methods from literature and then use it to simulate the absorptance of a single junction perovskite and a perovskite/silicon tandem cell. This shows that our method based on the Forouhi-Bloomer model is more accurate than existing methods in predicting the complex refractive index of perovskite for arbitrary bandgaps.","","en","journal article","","","","","","","","","","","Photovoltaic Materials and Devices","","",""
"uuid:db28aa9c-6a1b-4b1b-94e9-9e4257febb86","http://resolver.tudelft.nl/uuid:db28aa9c-6a1b-4b1b-94e9-9e4257febb86","Are men from Mars, women from Venus? Investigating the determinants behind the intention to use fully automated taxis","Zhu, Yonghan (Southwest University of Political Science and Law); Janssen, M.F.W.H.A. (TU Delft Engineering, Systems and Services); Pu, Chengyan (Zhejiang University)","","2024","Acceptance by customers is key to the success of shared autonomous vehicles (SAVs). However, only a small group of early technology-savvy customers currently use such vehicles, while the general population does not. Based on the Unified Theory of Acceptance and Use of Technology, Theory of Perceived Risk, and perceived threat of unemployment combined with knowledge of automated vehicles, this research develops an integrated model to investigate the determinants behind the intention to use fully automated taxis. Furthermore, it tested the differences between gender. Through the analysis of 539 samples, the findings showed that performance expectancy, effort expectancy, social influence, and knowledge of automated vehicles positively influence acceptance intention, while perceived safety risk and the perceived threat of unemployment were negatively related to behavioral intention. Moreover, effort expectancy, social influence, and perceived safety risk showed greater influence on females, while knowledge of automated vehicles exerted stronger effects on males.","Fully automated taxi; Gender differences; SAV acceptance; TPR; UTAUT","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-30","","Engineering, Systems and Services","","","",""
"uuid:de34d9db-a0ee-465d-b942-df631a37838c","http://resolver.tudelft.nl/uuid:de34d9db-a0ee-465d-b942-df631a37838c","How design professionals learn within collaborative research projects","Zielhuis, M.R.P. (TU Delft Design Conceptualization and Communication; Hogeschool Utrecht); Sleeswijk Visser, F. (TU Delft Design Conceptualization and Communication); Andriessen, Daan (Hogeschool Utrecht); Stappers, P.J. (TU Delft Design Conceptualization and Communication)","","2024","Collaborative research projects are great opportunities for the involved design professionals to learn. Many design professionals join in such collaborations to contribute with their existing professional expertise, but also to further develop and extend that expertise. However, learning by individuals is usually not the main aim, and we lack insight in the learning opportunities through collaboration in such projects. We propose that we need to understand this learning process better in order to make this happen more often and more effectively. This paper presents how four design professionals who each participated in different collaborative research projects look back on their learning processes. We interviewed each participant and drew a process map with them. The results show that these projects offer multifaceted learning opportunities and outcomes of important value for the professionals.The paper shows that their learning a) is not always easily recognised by the professionals themselves, b) benefits from their active engagement as learners, and c) requires supportive conditions in project arrangements. The paper provides guidelines for lead researchers, design professionals, as well as funding agencies to recognise and value this learning, to support explicit reflection and articulation, and to facilitate supportive learning conditions.","actionable knowledge; collaboration; Design practice; design research; roles","en","journal article","","","","","","","","","","","Design Conceptualization and Communication","","",""
"uuid:e6ecad30-4638-4430-a669-bfad8a13ae6b","http://resolver.tudelft.nl/uuid:e6ecad30-4638-4430-a669-bfad8a13ae6b","Integrated phononic waveguides in diamond","Ding, Sophie Weiyi (Harvard University); Pingault, B.J. (TU Delft QID/Taminiau Lab; TU Delft Communication QuTech; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Harvard University); Shao, Linbo (Harvard University; Virginia Tech); Sinclair, Neil (Harvard University); Machielse, Bartholomeus (Harvard University; AWS Center for Quantum Computing); Chia, Cleaven (Harvard University); Maity, Smarak (Harvard University); Lončar, Marko (Harvard University)","","2024","Efficient generation, guiding, and detection of phonons, or mechanical vibrations, are of interest in various fields, including radio-frequency communication, sensing, and quantum information. Diamond is a useful platform for phononics because of the presence of strain-sensitive spin qubits, and its high Young's modulus, which allows for low-loss gigahertz devices. We demonstrate a diamond phononic waveguide platform for generating, guiding, and detecting gigahertz-frequency surface acoustic wave (SAW) phonons. We generate SAWs using interdigital transducers integrated on AlN/diamond and observe SAW transmission at 4-5 GHz through both ridge and suspended waveguides, with wavelength-scale cross sections (approximately 1 m2) to maximize spin-phonon interaction. This work is a crucial step for developing acoustic components for quantum phononic circuits with strain-sensitive color centers in diamond.","","en","journal article","","","","","","","","","","","QID/Taminiau Lab","","",""
"uuid:58f5f372-b9f6-4c80-8bdc-1188c05a9894","http://resolver.tudelft.nl/uuid:58f5f372-b9f6-4c80-8bdc-1188c05a9894","TAIS: Transparent Amplifying Intelligent Surface for Indoor-To-Outdoor mmWave Communications","Liu, Bin (Katholieke Universiteit Leuven); Wang, Q. (TU Delft Embedded Systems); Pollin, Sofie (Katholieke Universiteit Leuven)","","2024","This paper presents a novel transparent amplifying intelligent surface (TAIS) architecture for uplink enhancement in indoor-To-outdoor mmWave communications. The TAIS is an amplifier-based transmissive intelligent surface that can refract and amplify the incident signal, instead of only refracting it with adjustable phase shift by most passive reconfigurable intelligent surfaces (RIS). With advanced indium tin oxide film and printing technology, TAIS can be fabricated on the windows without any visual effects. This paper primarily focuses on exploiting the TAIS-based architecture to boost the uplink spectral efficiency (SE) in indoor-To-outdoor mmWave communications. By jointly optimizing the TAIS's phase shift matrix and transmit power of the user equipment, the uplink SE can be maximized by exploiting the nonlinearity in the TAIS's amplification process. The key enabler is that we drive the optimal phase shift matrix that maximizes the SE and deduces its closed-form representation. The SE maximization is then proved to be transferred to the transmit power optimization problem. Another important enabler is that we design a low-complexity algorithm to solve the optimization problem using the difference of convex programming. Moreover, the asymptotic spectral efficiency under nonlinear amplification and power scaling law with infinitely large elements under both the sparse and rich scattering channel models are analyzed. Simulation results show that our proposed TAIS can increase the SE by up to 24.7% as compared to its alternative methods.","indoor-To-outdoor communication; mmWave MIMO; nonlinear amplification; Reconfigurable intelligent surface (RIS); spectral efficiency; transparent amplifying intelligent surface (TAIS)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-03","","","Embedded Systems","","",""
"uuid:3ed81b29-9a60-460b-b1a4-3560b46958cd","http://resolver.tudelft.nl/uuid:3ed81b29-9a60-460b-b1a4-3560b46958cd","Caracas, ciudad de secuelas: Prácticas de cuidado después de la emigración y el colapso","Gzyl, Stefan (TU Delft Theory, Territories & Transitions)","","2024","This article examines the caretaking practices of vacant domestic spaces amid a migratory crisis and generalized collapse. Caracas is conceptualized as a ‘city of aftermath’, where the material residues of modernity are reconfigured in response to the logic of crisis and the needs of migrants, re-signifying spaces and extending their life beyond the conditions of their production. The text is centered on the figure of the caretaker. Based on interviews, site visits, and photography, the article examines the daily routines of Carlos, who looks after more than twenty apartments in Caracas. His work is entwined with migrants’ trajectories and local needs, generating new economies and support networks around the maintenance and adaptation of vacant spaces. In this way, caretaking practices offer clues for a reading of the city that transcends progress/decline oppositions and their respective imaginaries: the new and the ruin.","crisis; maintenance; mantenimiento; middle class; repair clase media; reparación; ruin; ruina","es","journal article","","","","","","","","","","","Theory, Territories & Transitions","","",""
"uuid:93730881-1066-46c3-95a7-afed7b0c27cd","http://resolver.tudelft.nl/uuid:93730881-1066-46c3-95a7-afed7b0c27cd","Quantifying the impact of stiffness distributions on the dynamic behaviour of railway transition zones","Jain, A. (TU Delft Dynamics of Structures); Marykovskiy, Yuriy (ETH Zürich); Metrikine, A. (TU Delft Engineering Structures); van Dalen, K.N. (TU Delft Dynamics of Structures)","","2024","Railway transition zones (RTZs) are regions where abrupt track stiffness changes occur that may lead to dynamic amplifications and subsequent track deterioration. The design challenges for these zones arise due to variations in material properties in both the depth (trackbed layers composed of different materials) and longitudinal directions of the track, as well as temporal variations in mechanical properties of materials due to several external factors over the operational period. This research aims to investigate the effects of these variations in material properties (i.e., of the resulting stiffness distributions in vertical and longitudinal directions) on the behaviour of RTZs, assess from this perspective the performance of a novel transition structure called the SHIELD, and establish a methodology for designing a robust solution to mitigate the dynamic amplifications in these zones. Results indicate that stiffness variations in both vertical and longitudinal directions significantly influence the dynamic behaviour of the RTZs. The study also suggests a permissible range of stiffness ratios to control the amplification of strain energy in the most critical components of RTZs, both in the initial state as well as during the operational phase (where material properties may vary over time). Moreover, the proposed methodology offers a valuable tool for the design and evaluation of RTZs and is applicable to various transition types and a broad spectrum of material properties.","Railway transition zones; Dynamic amplifications; Material properties; Design limits; Stiffness ratios; Polynomial chaos expansion","en","journal article","","","","","","","","","","Engineering Structures","Dynamics of Structures","","",""
"uuid:9661b26e-8f7d-414f-a743-9b46e0718d6b","http://resolver.tudelft.nl/uuid:9661b26e-8f7d-414f-a743-9b46e0718d6b","Cosimulating Integrated Energy Systems with Heterogeneous Digital Twins: Matching a Connected World","Palensky, P. (TU Delft Electrical Sustainable Energy); Mancarella, Pierluigi (University of Melbourne; The University of Manchester); Hardy, Trevor (Pacific Northwest National Laboratory); Cvetkovic, M. (TU Delft Intelligent Electrical Power Grids)","","2024","Energy system integration promises in-creased resiliency and the unlocking of synergies, while also contributing to our goal of decarbonization. It is enabled by both old and new technologies, glued together with data and digital services. Hydrolyzers, heat pumps, distributed renewable generation, smart buildings, and the digital grid edge are all currently the subject of integration with the power system and the energy sector at large. To plan and operate such a multidisciplinary and multisectoral system properly, insight, tools, and expertise are all needed. This is exactly where the state of the art fails to deliver: tools for integrated energy systems (IESs) are still in their infancy, and many times, even academia treats these sectors separately, producing experts in each of them but not across.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-12","","Electrical Sustainable Energy","Intelligent Electrical Power Grids","","",""
"uuid:31e0d818-5f84-4b98-a9dd-21a72162fc62","http://resolver.tudelft.nl/uuid:31e0d818-5f84-4b98-a9dd-21a72162fc62","Discussion of “Coastal Defense Megaprojects in an Era of Sea-Level Rise: Politically Feasible Strategies or Army Corps Fantasies?”","Jonkman, Sebastiaan N. (TU Delft Hydraulic Structures and Flood Risk; Texas A&M University at Galveston); Merrell, William J. (Texas A&M University at Galveston)","","2024","The authors provide a valuable review of coastal defense megaprojects with storm surge barriers in the United States over the past decades. This review comes at an important moment: an increasing number of coastal regions are considering such solutions. Examples from the original paper are Houston, Miami, New York, Boston, and Norfolk in the US, Götenborg (Sweden), Shanghai, and Singapore (Tan 2022). A new barrier is under construction in Nieuwpoort (Belgium) (AMDK 2023). In addition, countries with existing barriers (the Netherlands, UK) are making plans to adapt, upgrade or replace surge barriers.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-09","","","Hydraulic Structures and Flood Risk","","",""
"uuid:e731427f-24d4-4e2d-a24a-4dc46ebf7972","http://resolver.tudelft.nl/uuid:e731427f-24d4-4e2d-a24a-4dc46ebf7972","Construction and application of an algebraic dual basis and the Fine-Scale Greens’ Function for computing projections and reconstructing unresolved scales","Shrestha, S. (TU Delft Aerodynamics; Universidad Politécnica de Madrid); Dekker, J. (TU Delft Numerical Analysis); Gerritsma, M.I. (TU Delft Aerodynamics); Hulshoff, S.J. (TU Delft Aerodynamics); Akkerman, I. (TU Delft Ship Hydromechanics and Structures)","","2024","In this paper, we build on the work of Hughes and Sangalli (2007) dealing with the explicit computation of the Fine-Scale Greens’ function. The original approach chooses a set of functionals associated with a projector to compute the Fine-Scale Greens’ function. The construction of these functionals, however, does not generalise to arbitrary projections, higher dimensions, or Spectral Element methods. We propose to generalise the construction of the required functionals by using dual functions. These dual functions can be directly derived from the chosen projector and are explicitly computable. We show how to find the dual functions for both the L2 and the H01 projections. We then go on to demonstrate that the Fine-Scale Greens’ functions constructed with the dual basis functions consistently reproduce the unresolved scales removed by the projector. The methodology is tested using one-dimensional Poisson and advection–diffusion problems, as well as a two-dimensional Poisson problem. We present the computed components of the Fine-Scale Greens’ function, and the Fine-Scale Greens’ function itself. These results show that the method works for arbitrary projections, in arbitrary dimensions. Moreover, the methodology can be applied to any Finite/Spectral Element or Isogeometric framework.","(Fine-Scale) Greens’ function; Advection–diffusion equation; Duality; Poisson equation; Projection; Variational multiscale","en","journal article","","","","","","","","","","","Aerodynamics","","",""
"uuid:c9882917-ff45-49a4-a020-d6bb963b6f99","http://resolver.tudelft.nl/uuid:c9882917-ff45-49a4-a020-d6bb963b6f99","Advancing Shallow Tunnel Construction in Soft Ground: The Pipe-Umbrella Box Jacking Method","Jiang, Xi (The Hong Kong Polytechnic University); Zhang, X. (TU Delft Geo-engineering); Zhang, Xiao (Shanghai Urban Construction Municipal Engineering (Group) Co. Ltd); Long, Luyuan (Student TU Delft); Bai, Yun (Tongji University); Huang, Baoshan (University of Tennessee)","","2024","The development of modern cities has often led to increased traffic congestion and limited usable space. One effective solution to these problems is to construct roadway tunnels, which can expand urban space and alleviate traffic congestion. However, building large underpass tunnels in urban areas, especially in soft ground, presents technical challenges owing to its extensive environmental disturbance. The pipe-umbrella box jacking method offers a promising solution to these challenges as this method does not require breaking the ground from the surface or disrupting surface traffic. This study reviews the key techniques of the pipe-umbrella box jacking method for constructing large rectangular tunnels with small burial depths in soft ground. The study focuses on three main technical issues: pipe umbrella installation, soil face excavation, and box jacking control. Furthermore, two tunnel projects in Shanghai, China, are presented as case studies to showcase the construction challenges and countermeasures during box jacking tunneling with pipe-umbrella. Practical construction experience has revealed that the installation of the pipe umbrella before box jacking serves as an effective method of ground pre-support. However, its performance can be influenced by factors such as pipe installation deviation and inter-pipe connection design. Both open-face steel grid extrusion (SGE) shields and closed-face earth pressure balanced (EPB) shields can be used for soil excavation during box jacking, with different work modes resulting in distinct ground deformation patterns. Additionally, lubrication grouting has been found to effectively reduce friction resistance and affect vertical ground deformation. The study also examines the lessons learned from case studies and proposes optimization measures. This study can serve as a valuable reference for the tunneling industry, providing insights into the pipe-umbrella box jacking method and its application in constructing large rectangular tunnels in soft ground.","Box Jacking Tunnel; EPB Shield; Pipe Umbrella; SGE Shield; Soft Ground","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:7df8183d-13a9-43e0-8a5b-5d467e33fd8a","http://resolver.tudelft.nl/uuid:7df8183d-13a9-43e0-8a5b-5d467e33fd8a","Identifying the Design Feature That Causes Project Delay in DfMA: A Dominant Element Analysis Method for Project Scheduling","Cao, Jianpeng (ETH Zürich); Zhang, Hang (ETH Zürich); Pan, Bo (ETH Zürich); Soman, R. K. (ETH Zürich); Savov, Anton (ETH Zürich); Hall, Daniel M. (TU Delft Design & Construction Management)","Turkan, Yelda (editor); Louis, Joseph (editor); Leite, Fernanda (editor); Ergan, Semiha (editor)","2024","Design for manufacturing and assembly (DfMA) is an engineering methodology which aims to increase ease of manufacture and efficiency of assembly by considering manufacturing and assembly constraints in the design process. However, current DfMA approaches in the construction sector are not automated enough to identify the design features that may cause project delay in real time. This leads to longer design cycle. Also, current scheduling algorithms rely on human intervention to generate activity network from a design output. Addressing these inefficiencies, we propose an interpretative machining learning model to predict the construction duration given a design output. More importantly, the same model identifies the design features that may cause the most delay in the project. The model is trained on a residential design dataset with various features, such as layout, geometry, and element typology. The output of the model is the project duration and an importance map, indicating the influence each feature of the given design has on the total project duration. The results from this model can considerably reduce the design cycle by supporting architects to create fabrication and assembly aware design even when they have little knowledge of production and assembly processes. This model will contribute to a novel computational approach for DfMA.","","en","conference paper","American Society of Civil Engineers (ASCE)","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-25","","","Design & Construction Management","","",""
"uuid:f53afdd2-98e1-42ab-8308-82dbd64d076b","http://resolver.tudelft.nl/uuid:f53afdd2-98e1-42ab-8308-82dbd64d076b","A Systematic Umbrella Review on Computational Thinking Assessment in Higher Education","Zhang, X. (TU Delft Web Information Systems); Aivaloglou, E.A. (TU Delft Web Information Systems); Specht, M.M. (TU Delft Web Information Systems)","","2024","Computational Thinking (CT) is considered a core 21st century digital skill. The aspect of assessment is crucial and knowing what, who, when, how, and where to assess is important for assessment design. In this study, we conducted an umbrella review to gain insights regarding CT assessment in higher education. In total, we analyzed 11 reviews, focusing on: (1) bibliographical and methodological characteristics of the reviews; (2) aspects relevant of assessment design, including a) assessed constructs, b) applied assessment methodologies, and c) assessment contexts. Our findings suggest an increased attention on this topic. However, hardly any reviews reasoned the selection of their review methodology, and most of the reviews did not thoroughly examine existing reviews. Regarding assessment design aspects, most reviews did not confine their scope to higher education; however, findings on interventions and educational settings show commonalities. We identified 120 unique assessed constructs and around 10 types of assessment methods. Though a combined use of distinct assessment methods is suggested in reviews, guidelines for appropriate assessment design are yet to be constructed. Based on the findings, we argue that it is necessary to explore different combinations of assessment design in various contexts to construct assessment guidelines.","assessment; computational thinking; higher education; umbrella review","en","review","","","","","","","","","","","Web Information Systems","","",""
"uuid:e7fa2cc8-37e6-4750-8782-f7a068e40837","http://resolver.tudelft.nl/uuid:e7fa2cc8-37e6-4750-8782-f7a068e40837","Learning-by-exporting in South Africa: The influence of global value chain (GVC) participation and technological capability*","Mazzi, Caio Torres (Universiteit Maastricht); Ndubuisi, G.O. (TU Delft Economics of Technology and Innovation); Avenyo, Elvis (University of Johannesburg)","","2024","Using the South African Revenue Service and National Treasury firm-level panel data for 2009–2017, this paper investigates how trade related to the global value chain (GVC) affects the performance of manufacturing firms in South Africa. The paper uses extant classifications of internationally traded products to identify different categories of GVC-related products and compares the productivity premium of international traders for these different categories. Also, the paper investigates possible differences in learning-by-exporting effects across the identified categories of GVC-related products by estimating the effect of exporting before and after entry into foreign markets. The results confirm that GVC-related trade is associated with a higher productivity premium compared with traditional trade. However, within the categories of exporters, only the firms that trade in GVC-related products and simultaneously engage in research and development in the post-entry periods appear to learn from exporting. Our results underscore the gains of GVC integration in terms of the associated productivity premia and highlight the need for GVC-integrated firms to invest in building technological capacity.","exporter premia; GVCs; parts and components; South Africa","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-29","","","Economics of Technology and Innovation","","",""
"uuid:47a8c298-b76f-4db8-8d1c-030afe91cf1c","http://resolver.tudelft.nl/uuid:47a8c298-b76f-4db8-8d1c-030afe91cf1c","Electrochemical arsenite oxidation for drinking water treatment: Mechanisms, by-product formation and energy consumption","Kraaijeveld, E. (TU Delft Sanitary Engineering); Rijsdijk, S. (TU Delft Sanitary Engineering); van der Poel, S. (TU Delft Sanitary Engineering; Dunea); van der Hoek, J.P. (TU Delft Sanitary Engineering); Rabaey, K. (Universiteit Gent); van Halem, D. (TU Delft Sanitary Engineering)","","2024","The mechanisms and by-product formation of electrochemical oxidation (EO) for As(III) oxidation in drinking water treatment using groundwater was investigated. Experiments were carried out using a flowthrough system, with an RuO 2/IrO 2 MMO Ti anode electrode, fed with synthetic and natural groundwater containing As(III) concentrations in a range of around 75 and 2 µg/L, respectively. Oxidation was dependent on charge dosage (CD) [C/L] and current density [A/m 2], with the latter showing plateau behaviour for increasing intensity. As(III) concentrations of <0.3 µg/L were obtained, indicating oxidation of 99.9 % of influent As(III). Achieving this required a higher charge dosage for the natural groundwater (>40 C/L) compared to the oxidation in the synthetic water matrix (20 C/L), indicating reaction with natural organic matter or other compounds. As(III) oxidation in groundwater required an energy consumption of 0.09 and 0.21 kWh/m 3, for current densities of 20 and 60 A/m 2, respectively. At EO settings relevant for As(III) oxidation, in the 30–100 C/L CD range, the formation of anodic by-products, as trihalomethanes (THMs) (0.11–0.75 µg/L) and bromate (<0.2 µg/L) was investigated. Interestingly, concentrations of the formed by-products did not exceed strictest regulatory standards of 1 µg/L, applicable to Dutch tap water. This study showed the promising perspective of EO as electrochemical advanced oxidation process (eAOP) in drinking water treatment as alternative for the conventional use of strong oxidizing chemicals.","Arsenic; Groundwater; THMs; Bromate","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-19","","","Sanitary Engineering","","",""
"uuid:0dadd35f-2705-4fa8-a00e-837cc47d18e3","http://resolver.tudelft.nl/uuid:0dadd35f-2705-4fa8-a00e-837cc47d18e3","An airbrush 3D printer: Additive manufacturing of relaxor ferroelectric actuators","IJssel de Schepper, S.R. (TU Delft Micro and Nano Engineering); Hunt, A. (TU Delft Micro and Nano Engineering)","","2024","The additive manufacturing of electroactive polymer (EAP) devices poses significant challenges due to their distinct structure and dissimilar properties of their constituent materials. It requires deposition of multiple functional materials with different properties, achieving μm-scale resolution in layer thickness, and executing incremental deposition and curing steps while preserving the previously deposited functional material layers. This study introduces an airbrush 3D printer concept and employs it for fabricating EAP transducers. An airbrush 3D printer was constructed by adapting a standard extrusion printer platform and integrating it with a two fluid atomizer (i.e. an airbrush) as the deposition tool. A process was developed for printing of the bending P(VDF-TrFE-CTFE) actuators with carbon black electrodes, and actuators with a single and dual EAP layers were fabricated. The airbrush printer attained in-plane resolution of 0.5mm, thickness resolutions of 0.63 μm and allowed atomizing up to 7% P(VDF-TrFE-CTFE) solutions. The 18 mm × 4 mm EAP actuators achieved 340μm (440 Vpp) and 3.7 mm (400 Vpp, 104 Hz) tip deflections respectively in quasi-static and resonant operation. Airbrush printing therefore proved to be a robust method for printing precursor materials with a wide range of properties, and is anticipated to be a versatile approach for printing other passive and stimuli-responsive materials and devices.","Additive manufacturing; Airbrush 3D printer; Electroactive polymer; Smart material actuator; Spray printing","en","journal article","","","","","","","","","","","Micro and Nano Engineering","","",""
"uuid:fdd2f04f-7f85-47f5-aa41-33890001c155","http://resolver.tudelft.nl/uuid:fdd2f04f-7f85-47f5-aa41-33890001c155","Homological Quantum Rotor Codes: Logical Qubits from Torsion","Vuillot, C. (Lorraine University); Ciani, A. (Forschungszentrum Jülich GmbH); Terhal, B.M. (TU Delft Discrete Mathematics and Optimization; QuTech)","","2024","We formally define homological quantum rotor codes which use multiple quantum rotors to encode logical information. These codes generalize homological or CSS quantum codes for qubits or qudits, as well as linear oscillator codes which encode logical oscillators. Unlike for qubits or oscillators, homological quantum rotor codes allow one to encode both logical rotors and logical qudits in the same block of code, depending on the homology of the underlying chain complex. In particular, a code based on the chain complex obtained from tessellating the real projective plane or a Möbius strip encodes a qubit. We discuss the distance scaling for such codes which can be more subtle than in the qubit case due to the concept of logical operator spreading by continuous stabilizer phase-shifts. We give constructions of homological quantum rotor codes based on 2D and 3D manifolds as well as products of chain complexes. Superconducting devices being composed of islands with integer Cooper pair charges could form a natural hardware platform for realizing these codes: we show that the 0-π qubit as well as Kitaev’s current-mirror qubit—also known as the Möbius strip qubit—are indeed small examples of such codes and discuss possible extensions.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-20","","","Discrete Mathematics and Optimization","","",""
"uuid:8ee85a7c-552a-481d-b217-84760274b072","http://resolver.tudelft.nl/uuid:8ee85a7c-552a-481d-b217-84760274b072","Mitigating suspended-sediment environmental pressure in subsea engineering through colliding turbidity currents","Alhaddad, S.M.S. (TU Delft Offshore and Dredging Engineering); Elerian, M.F.A.I. (TU Delft Offshore and Dredging Engineering)","","2024","Turbidity currents have extensively been explored in quiescent environments. However, during several underwater activities (e.g., dredging and deep sea mining), generated turbidity currents could travel in opposite directions and interact with each other, which could largely influence their hydrodynamics and sediment transport capacity. Therefore, we carried out a set of dual-lock-exchange experiments to study the interaction of colliding turbidity currents. Our experimental results show that the interaction of identical currents results in the reflection of both currents with almost no mixing, forcing them to travel in the opposite direction of the pre-collision one. In contrast, when a turbidity current interacts with a lighter, less-energetic current, clear mixing is observed. Furthermore, it is revealed that the collision of turbidity currents reduces the suspended sediment transported by them, which is favorable from an environmental point of view, and slightly increases the vertical dispersion of particles. In the case of two identical counterflowing currents, a 35% reduction in mass flux, accompanied by a 6% increase in turbidity current thickness, was observed in our experiments.","Turbidity currents; Dual-lock-exchange experiments; Dredging; Deep Sea Mining; Polymetallic Nodules; Environmental Impact; Breaching","en","journal article","","","","","","","","","","","Offshore and Dredging Engineering","","",""
"uuid:59ceaebc-28f7-4eb4-84c0-09e2b67ac277","http://resolver.tudelft.nl/uuid:59ceaebc-28f7-4eb4-84c0-09e2b67ac277","Buffer scheduling for improving on-time performance and connectivity with a multi-objective simulation–optimization model: A proof of concept for the airline industry","van Schilt, Isabelle M. (TU Delft Policy Analysis); van Kalker, Jonna (KLM Royal Dutch Airlines); Lefter, I. (TU Delft System Engineering); Kwakkel, J.H. (TU Delft Policy Analysis); Verbraeck, A. (TU Delft Policy Analysis)","","2024","Schedule design in the transportation and logistics sector is a widely studied problem. Transport service providers, such as the train industry and aviation, aim for schedules to be on-time according to the planning (i.e., on-time performance or OTP) in order to increase the service level by ensuring that passengers actually make their connections and to reduce costs. Transportation services also aim for schedules that serve a high variety of destinations and frequency of connections (i.e., connectivity). OTP and connectivity are both highly dependent on buffer time: more lucrative connections can often be offered by reducing the buffer time in the schedule, while more delay can be absorbed by more buffer time. Given strict constraints on the minimum turnaround time of aircraft and minimum (and maximum acceptable) transfer times of passengers, assigning buffer time in an already tightly planned schedule to optimize OTP and connectivity simultaneously is a big challenge. This research presents a novel multi-objective formulation of a daily flight schedule where buffer scheduling is used to ensure the optimal balance between OTP of the schedule and the passenger connections as connectivity, given the tight restrictions. This problem formulation is solved using a simulation–optimization framework. Specifically, we use the Multi-Objective Evolutionary Algorithm (MOEA) BORG. As a proof of concept, a daily European flight schedule of a large international airline is optimized on both OTP and connectivity. The results demonstrate that the presented multi-objective formulation and associated solving through simulation–optimization can result in candidate schedules with both better on-time performance and a higher connectivity.","Airline scheduling; Buffer allocation; Connectivity; Multi-objective optimization; On-time performance","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:40d7eeec-5eeb-4413-b9b5-85e58ef96512","http://resolver.tudelft.nl/uuid:40d7eeec-5eeb-4413-b9b5-85e58ef96512","Process design and downstream optimization of the direct synthesis route for cleaner production of dimethyl ether from biogas","Fedeli, M. (Politecnico di Milano; Université de Toulouse); Negri, F. (Politecnico di Milano; Itelyum Regeneration Spa, Lodi); Bornazzini, A. (TU Delft ChemE/Product and Process Engineering; Politecnico di Milano); Montastruc, L. (Université de Toulouse); Manenti, F. (Politecnico di Milano); Kiss, A.A. (TU Delft ChemE/Product and Process Engineering)","","2024","This study investigates an innovative method to produce dimethyl ether (DME) by direct synthesis from syngas derived from biogas. The proposed process was rigorously simulated in Aspen Plus, highlighting the main sections: (i) biogas tri-reforming, (ii) dimethyl-ether synthesis, and (iii) DME purification. The tri-reforming section has a CO2 and CH4 conversion of 27.3% and 96.2%, respectively A novel catalyst suitable for CO2-rich feed was chosen for the DME production to allow 60% conversion of CO2. Product separation is achieved via several absorption and distillation columns, ensuring that the operating conditions are kept mild to avoid expensive refrigeration. An optimization analysis was performed to identify the most suitable layout of the downstream process. This was identified through the evaluation of performance indicators such as utility usage and operating expenses. A wide range of purification strategies have been evaluated, and two scenarios are proposed based on the results. Configuration A produces 5.34 ktpy DME and 1.26 ktpy methanol, while Configuration B produces exclusively 6.21 ktpy DME. The process configurations were analysed by means of key techno-economic indicators and sustainability metrics. Both processes have an energy intensity of 14.5 kWh/kg. The reforming unit has a negligible footprint as it is thermally sustained from biogas combustion, but the reboilers are the main contributors for plant CO2 emissions. Configuration B has the best economic value with 11,634 k€ of NPV after 25 years and a payback time of 4 years.","DME direct synthesis; Green processing; Process optimization; Process simulation; Waste-to-Fuel","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:32be3762-b749-4fc6-ab3b-6fb5700ef8b9","http://resolver.tudelft.nl/uuid:32be3762-b749-4fc6-ab3b-6fb5700ef8b9","Predicting elbow load based on individual pelvis and trunk (inter)segmental rotations in fastball pitching","Gomaz, L. (TU Delft Statistics); van Trigt, B. (TU Delft Biomechatronics & Human-Machine Control); van der Meulen, F.H. (Vrije Universiteit Amsterdam); Veeger, H.E.J. (TU Delft Biomechatronics & Human-Machine Control)","","2024","The baseball pitch is a repetitive, full-body throwing motion that exposes the elbow to significant loads, leading to a high incidence of elbow injuries. Elbow injuries in pitching are often attributed to high external valgus torques as these are generally considered to be a good proxy for the load on the Ulnar Collateral Ligament. The aim of the study is to contribute to elbow load monitoring by developing a prediction model based on the pelvis and trunk peak angular velocities and their separation time. Eleven male youth elite baseball pitchers (age 17 ± 2.2 years) threw 25 fastballs at full effort off a mound. Two-level varying-intercept, varying-slope Bayesian models were used to predict external valgus torque based on (inter)segmental rotation in fastball pitching with pitcher’s weight and height added to strengthen the individualisation of the prediction. The results revealed the high predictive performance of the models including a set of kinematic parameters trunk peak angular velocity and the separation time between the pelvis and trunk peak angular velocities. Such an approach allows individualised prediction of the external valgus torque for each pitcher, which has a great practical advantage compared to group-based predictions in terms of injury assessment and injury prevention.","baseball; External valgus torque; injury prevention; kinetic chain; UCL injuries","en","journal article","","","","","","","","","","","Statistics","","",""
"uuid:9ff83a17-2900-4d39-a538-6675e1fa8bfa","http://resolver.tudelft.nl/uuid:9ff83a17-2900-4d39-a538-6675e1fa8bfa","Analyzing coastal erosion and sedimentation using Sentinel-1 SAR change detection: An application on the Volta Delta, Ghana","di Biase, V. (Universiteit Utrecht); Hanssen, R.F. (TU Delft Mathematical Geodesy and Positioning)","","2024","Ghana's coastline has been facing erosion and sedimentation phenomena for several decades, resulting in a serious threat to life and property considering that major urban settlements are located on the coast. In this region, there has been a lack of emphasis on comprehensive, large-scale investigations into coastal changes: prior research has predominantly centered on site-specific assessments. These studies have revealed alarming erosion rates, with reports indicating that nearly ten meters are lost annually. The use of high-resolution remotely sensed data can be a consistent support in regions where physical or economic obstacles interfere with collecting in situ information. In particular, the use of continuous all-weather SAR data may facilitate the evaluation of erosion and sedimentation phenomena in coastal areas. In this paper, we apply SAR data over a time period between 2017 and 2021. Sentinel-1 data are pre-processed using the Google Earth Engine platform, and a dedicated algorithm is then applied to identify and quantify erosion and sedimentation processes. Optical images are used as a reference for detecting the location of two areas where consistent sedimentation and erosion phenomena occurred in the considered four years. The results demonstrate that SAR backscattering variations over time offer a reliable method for monitoring coastal changes. This approach enables the identification of the type of phenomena occurring - sedimentation or erosion -, and allows for the quantification of their intensity and dimensions over time. The method can be worldwide applied once the appropriate thresholds are evaluated and help in predictive studies and environmental planning.","Change detection; Coastal environment; Coastal erosion; SAR; Sentinel-1","en","journal article","","","","","","","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:587d267d-7d7c-4121-937e-d1e43acb49dc","http://resolver.tudelft.nl/uuid:587d267d-7d7c-4121-937e-d1e43acb49dc","Centrifuge fractionation during purification of cellulose nanocrystals after acid hydrolysis and consequences on their chiral self-assembly","Svagan, Anna J. (KTH Royal Institute of Technology); Vilaplana, Francisco (KTH Royal Institute of Technology); Pettersson, Torbjörn (KTH Royal Institute of Technology); Ravi Anusuyadevi, P. (TU Delft Team Arjan Mol; KTH Royal Institute of Technology); Henriksson, Gunnar (KTH Royal Institute of Technology); Hedenqvist, Mikael (KTH Royal Institute of Technology)","","2024","The inherent colloidal dispersity (due to length, aspect ratio, surface charge heterogeneity) of CNCs, when produced using the typical traditional sulfuric acid hydrolysis route, presents a great challenge when interpreting colloidal properties and linking the CNC film nanostructure to the helicoidal self-assembly mechanism during drying. Indeed, further improvement of this CNC preparation route is required to yield films with better control over the CNC pitch and optical properties. Here we present a modified CNC-preparation protocol, by fractionating and harvesting CNCs with different average surface charges, rod lengths, aspect ratios, already during the centrifugation steps after hydrolysis. This enables faster CNC fractionation, because it is performed in a high ionic strength aqueous medium. By comparing dry films from the three CNC fractions, discrepancies in the CNC self-assembly and structural colors were clearly observed. Conclusively, we demonstrate a fast protocol to harvest different populations of CNCs, that enable tailored refinement of structural colors in CNC films.","Cellulose nanocrystals; Fractionation; Structural colors; Sulfuric acid hydrolysis","en","journal article","","","","","","","","","","","Team Arjan Mol","","",""
"uuid:576b129f-b770-42b4-81d1-860928d411c2","http://resolver.tudelft.nl/uuid:576b129f-b770-42b4-81d1-860928d411c2","Albumin Protein Impact on Early-Stage In Vitro Biodegradation of Magnesium Alloy (WE43)","Imani, Amin (University of British Columbia; Monash University); Rahimi, E. (TU Delft Materials Science and Engineering); Lekka, Maria (CIDETEC); Andreatta, Francesco (University of Udine); Magnan, Michele (University of Udine); Gonzalez Garcia, Y. (TU Delft Team Yaiza Gonzalez Garcia); Mol, J.M.C. (TU Delft Team Arjan Mol); Raman, R. K. Singh (Monash University); Fedrizzi, Lorenzo (University of Udine); Asselin, Edouard (University of British Columbia)","","2024","Mg and its alloys are promising biodegradable materials for orthopedic implants and cardiovascular stents. The first interactions of protein molecules with Mg alloy surfaces have a substantial impact on their biocompatibility and biodegradation. We investigate the early-stage electrochemical, chemical, morphological, and electrical surface potential changes of alloy WE43 in either 154 mM NaCl or Hanks’ simulated physiological solutions in the absence or presence of bovine serum albumin (BSA) protein. WE43 had the lowest electrochemical current noise (ECN) fluctuations, the highest noise resistance (Zn = 1774 Ω·cm2), and the highest total impedance (|Z| = 332 Ω·cm2) when immersed for 30 min in Hanks’ solution. The highest ECN, lowest Zn (1430 Ω·cm2), and |Z| (49 Ω·cm2) were observed in the NaCl solution. In the solutions containing BSA, a unique dual-mode biodegradation was observed. Adding BSA to a NaCl solution increased |Z| from 49 to 97 Ω·cm2 and decreased the ECN signal of the alloy, i.e., the BSA inhibited corrosion. On the other hand, the presence of BSA in Hanks’ solution increased the rate of biodegradation by decreasing both Zn and |Z| while increasing ECN. Finally, using scanning Kelvin probe force microscopy (SKPFM), we observed an adsorbed nanolayer of BSA with aggregated and fibrillar morphology only in Hanks’ solution, where the electrical surface potential was 52 mV lower than that of the Mg oxide layer.","magnesium alloy; protein adsorption; corrosion; biodegradation; surface potential","en","journal article","","","","","","","","","","Materials Science and Engineering","Team Yaiza Gonzalez Garcia","","",""
"uuid:6ea5060c-1f83-471c-9473-68a32fcf26ee","http://resolver.tudelft.nl/uuid:6ea5060c-1f83-471c-9473-68a32fcf26ee","Fiber-Optic Pedicle Probes to Advance Spine Surgery through Diffuse Reflectance Spectroscopy","Losch, M.S. (TU Delft Medical Instruments & Bio-Inspired Technology); Heintz, J.D. (Student TU Delft); Edström, Erik (Karolinska Institutet; Capio Spine Center); Terander, Adrian Elmi (Karolinska Institutet; Capio Spine Center); Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology); Hendriks, B.H.W. (TU Delft Medical Instruments & Bio-Inspired Technology)","","2024","Diffuse Reflectance Spectroscopy (DRS) can provide tissue feedback for pedicle screw placement in spine surgery, yet the integration of fiber optics into the tip of the pedicle probe, a device used to pierce through bone, is challenging, since the optical probing depth and signal-to-noise ratio (SNR) are affected negatively compared to those of a blunt DRS probe. Through Monte Carlo simulations and optical phantom experiments, we show how differences in the shape of the instrument tip influence the acquired spectrum. Our findings demonstrate that a single bevel with an angle of 30∘ offers a solution to anticipate cortical breaches during pedicle screw placement. Compared to a blunt probe, the optical probing depth and SNR of a cone tip are reduced by 50%. The single bevel tip excels with 75% of the optical probing depth and a SNR remaining at approximately ⅔, facilitating the construction of a surgical instrument with integrated DRS.","Diffuse Reflectance Spectroscopy; spine surgery; breach detection; fiber optics; probe design","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:ebd6177f-bfff-4b3e-b34b-d494e5586a5b","http://resolver.tudelft.nl/uuid:ebd6177f-bfff-4b3e-b34b-d494e5586a5b","Critical factors for effective resident participation in neighborhood rehabilitation in Wuhan, China: From the perspectives of diverse stakeholders","Li, Y. (TU Delft Design & Construction Management); Tao, Y. (University of Cambridge); Qian, QK (TU Delft Design & Construction Management); Mlecnik, E. (TU Delft Real Estate Management); Visscher, H.J. (TU Delft Design & Construction Management)","","2024","Resident participation is essential for neighborhood rehabilitation. It requires the active involvement of residents and efficient management by organizers. To improve the effectiveness of resident participation, it is necessary to understand the critical success factors (CSFs) underlying it. However, previous research has examined the critical factors from a single-stakeholder perspective, overlooking potential differences in perceptions among stakeholders with diverse roles and rehabilitation experiences. Based on 30 interviews and 255 questionnaires from six stakeholder groups in Wuhan, China, this study explores how the perception of critical factors for effective resident participation varies among local government, community-based organization, designer, contractor, consulting party, and resident. Thirty-seven factors were identified and compared among the stakeholders. Financial Incentive (for participation organizers) was identified as the most critical factor for effective resident participation, followed by Information Disclosure and Transparency, and Trust. Results from the analysis of variance (ANOVA) show that the six groups differed significantly in the importance of most factors (25/37), especially in Participant Education and Prejudice against the Working Group. Interview results indicate that the COVID-19 pandemic and rehabilitation experience changed stakeholders’ perceived importance of some factors. Specifically, in future RP initiatives, extra emphasis could be placed on Trait and Capacity (of the working group) and Participation-assistance Technologies. Stakeholders regarded these two factors as more critical as their rehabilitation experience accumulated. By understanding stakeholders' conflicting and changing perceptions of effective resident participation, suggestions were proposed to each stakeholder group to fulfill their distinct participation objectives and improve the overall effectiveness of participation practices.","resident participation; neighborhood rehabilitation; Critical success factor (CSF); stakeholder perception; COVID-19 pandemic; China","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:c38086ce-2eac-4f0e-8668-f41c6b1c8920","http://resolver.tudelft.nl/uuid:c38086ce-2eac-4f0e-8668-f41c6b1c8920","How can airports prepare for future public health disruptions? Experiences and lessons learned during the COVID-19 pandemic from a systemic perspective based on expert interviews","Nieuwborg, A.B.D. (TU Delft Responsible Marketing and Consumer Behavior); Melles, M. (TU Delft Applied Ergonomics and Design); Hiemstra-van Mastrigt, S. (TU Delft Responsible Marketing and Consumer Behavior); Santema, S.C. (TU Delft Responsible Marketing and Consumer Behavior)","","2024","The COVID-19 pandemic proved to be an existential public health and economic crisis for the airport system. An interview study was conducted using Amsterdam Airport Schiphol as a use case to prepare for future public health disruptions. The study aimed to uncover key experiences and lessons learned by an airport system during the COVID-19 pandemic by interviewing 16 experts from airport operators, airlines, public health agencies, security services, and the government. After thematic analysis, four themes emerged. The first theme addressed the limited readiness of the airport system; the COVID-19 pandemic seemed unimaginable regardless of prior experiences with infectious diseases or weak signals. The second theme depicts an airport system running behind the facts, one that had difficulties implementing operational interventions and had to deal with extensive reorganisations. The third theme illustrated the complex relational dynamics within the airport system, such as the hesitancy of public health stakeholders towards aviation stakeholders and the government utilising a top-down approach. Finally, theme four provides lessons learned for the future whereby actively fostering a systemic approach, sensemaking capabilities, and informal relations are recommended. Current constructions like Crisis Management Teams and the Airport Operations Centre support these learnings. Further reflection and operationalisation of the study's findings are critical to proactively supporting the airport system's transition from a potential pandemic liability to a strategic asset in mitigating public health disruptions.","Air transportation; Airport strategy; Crisis management; Uncertainty","en","journal article","","","","","","","","","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:dbb987f9-4b41-487a-b7e3-1286db7d2d4e","http://resolver.tudelft.nl/uuid:dbb987f9-4b41-487a-b7e3-1286db7d2d4e","Spatial Design Thinking in Coastal Defence Systems: Overtopping Dikes in Southend-On-Sea","Iuorio, Luca (TU Delft Environmental Technology and Design); Wüthrich, D. (TU Delft Hydraulic Structures and Flood Risk); Teng, Djimin (Student TU Delft); Hooimeijer, F.L. (TU Delft Environmental Technology and Design)","","2024","Coastal dikes have been built for millennia to protect inhabited lands from exceptional high tides and storm events. Currently, many European countries are developing specific programs to integrate the construction of new dikes (or the raising of existing ones) into the built environment to face sea level rising. Technical difficulties in succeeding in this operation are questioning the paradigm of protection for the long term, pointing out the need for alternative strategies of adaptation that are not yet fully explored. This paper elaborates on innovative models to deal with coastal flooding, presenting the results of an interdisciplinary research and design process for the case-study of Southend-on-Sea (UK). Detailed numerical simulations are used to develop a spatial strategy to accommodate water during extreme events, introducing different prototypes of dike designs that include seawalls, enhanced roughness through rock and stepped revetments, as well as vegetation. The overall goal is to push forward the traditional approach of planning water protection infrastructure within the solely field of civil engineering. It elaborates on the integration of the disciplines of spatial design and engineering and presents novel advances in terms of spatial design for the revetment of overtopping dikes.","engineering; spatial design; interdisciplinary; coastal dikes; roughness","en","journal article","","","","","","","","","","","Environmental Technology and Design","","",""
"uuid:0691fd48-7699-4bdc-8819-1c803486bc28","http://resolver.tudelft.nl/uuid:0691fd48-7699-4bdc-8819-1c803486bc28","A model analysis of centimeter-long electron transport in cable bacteria","van der Veen, J.R. (TU Delft BT/Environmental Biotechnology; Kavli institute of nanoscience Delft); Valianti, S. (TU Delft QN/Blanter Group; Kavli institute of nanoscience Delft); van der Zant, H.S.J. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Blanter, Y.M. (TU Delft QN/Blanter Group; Kavli institute of nanoscience Delft); Meysman, F.J.R. (TU Delft BT/Environmental Biotechnology; Universiteit Antwerpen)","","2024","The recent discovery of cable bacteria has greatly expanded the known length scale of biological electron transport, as these multi-cellular bacteria are capable of mediating electrical currents across centimeter-scale distances. To enable such long-range conduction, cable bacteria embed a network of regularly spaced, parallel protein fibers in their cell envelope. These fibers exhibit extraordinary electrical properties for a biological material, including an electrical conductivity that can exceed 100 S cm −1. Traditionally, long-range electron transport through proteins is described as a multi-step hopping process, in which the individual hopping steps are described by Marcus electron transport theory. Here, we investigate to what extent such a classical hopping model can explain the conductance data recorded for individual cable bacterium filaments. To this end, the conductive fiber network in cable bacteria is modelled as a set of parallel one-dimensional hopping chains. Comparison of model simulated and experimental current(I)/voltage(V) curves, reveals that the charge transport is field-driven rather than concentration-driven, and there is no significant injection barrier between electrodes and filaments. However, the observed high conductivity levels (>100 S cm −1) can only be reproduced, if we include much longer hopping distances (a > 10 nm) and lower reorganisation energies (λ < 0.2 eV) than conventionally used in electron relay models of protein structures. Overall, our model analysis suggests that the conduction mechanism in cable bacteria is markedly distinct from other known forms of long-range biological electron transport, such as in multi-heme cytochromes.","","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:563ecf9f-4ef5-435f-9ca1-d211e8871b51","http://resolver.tudelft.nl/uuid:563ecf9f-4ef5-435f-9ca1-d211e8871b51","Mode-{I, III} multiaxial fatigue of welded joints in steel maritime structures: Effective notch stress based resistance incorporating strength and mechanism contributions","Bufalari, G. (TU Delft Ship Hydromechanics and Structures); den Besten, J.H. (TU Delft Ship and Offshore Structures); Kaminski, M.L. (TU Delft Ship and Offshore Structures)","","2024","The response of maritime structures can be multiaxial, involving predominant mode-I and non-negligible mode-III components. Adopting a stress distribution formulation based effective notch stress as fatigue strength parameter for mixed mode-{I, III} multiaxial fatigue assessment purposes, a mode-I equivalent von Mises type of failure criterion has been established at the critical fracture plane. Counting includes a cycle-by-cycle non-proportionality measure and damage accumulation is based on a linear model. Distinguished mode specific and material characteristic strength and mechanism contributions in terms of respectively the resistance curve intercept and mean stress induced response ratio coefficient, resistance curve slope and material characteristic length, have been incorporated. Evaluating the mid-cycle fatigue resistance, the outperformance is impressive. The analysed multiaxial mode-{I, III} data fits the uniaxial mode-I reference data scatter band and a single resistance curve can be used for fatigue assessment.","Effective notch stress; Fatigue; Multiaxiality; Strength and mechanism; Welded joints","en","journal article","","","","","","","","","","","Ship Hydromechanics and Structures","","",""
"uuid:41f4007f-e008-41f4-b6ab-7feeb7e63482","http://resolver.tudelft.nl/uuid:41f4007f-e008-41f4-b6ab-7feeb7e63482","Storage Standards and Solutions, Data Storage, Sharing, and Structuring in Digital Health: A Brazilian Case Study","Rodrigues de Oliveira, Nicollas (Universidade Federal Fluminense); de Rezende dos Santos, Yago (Universidade Federal Fluminense); Rocha Mendes, Ana Carolina (Universidade Federal Fluminense); Nunes Nasseh Barbosa, Guilherme (Universidade Federal Fluminense); Tuler de Oliveira, M. (TU Delft Information and Communication Technology); Valle, Rafael (Rede Nacional de Ensino e Pesquisa); Scherly Varela Medeiros, Dianne (Universidade Federal Fluminense); Mattos, Diogo Menezes Ferrazani (Universidade Federal Fluminense)","","2024","The COVID-19 pandemic has highlighted the necessity for agile health services that enable reliable and secure information exchange, but achieving proper, private, and secure sharing of EMRs remains a challenge due to diverse data formats and fragmented records across multiple data silos, resulting in hindered coordination between healthcare teams, potential medical errors, and delays in patient care. While centralized EMR systems pose privacy risks and data format diversity complicates interoperability, blockchain technology offers a promising solution by providing decentralized storage, ensuring data integrity, enhancing access control, eliminating intermediaries, and increasing efficiency in healthcare. By focusing on a Brazilian case study, this paper explores the significance of EMR standards, security challenges, and blockchain-based approaches to promote interoperability and secure data sharing in the healthcare industry.","healthcare standards; blockchain","en","review","","","","","","","","","","","Information and Communication Technology","","",""
"uuid:2c309d76-800f-47c3-a702-3aca6f99284c","http://resolver.tudelft.nl/uuid:2c309d76-800f-47c3-a702-3aca6f99284c","Textile Membrane for Façade Retrofitting: Exploring Fabric Potentialities for the Development of Innovative Strategies","Procaccini, Giulia (Polytechnic of Milan); Prieto, Alejandro (Diego Portales University); Knaack, U. (TU Delft Architectural Technology); Monticelli, Carol (Polytechnic of Milan); Konstantinou, T. (TU Delft Architectural Technology)","","2024","The European building stock demands urgent renovation due to the age of the buildings, their expected lifetime, and their excessive energy consumption, which accounts for more than a third of the EU’s total emissions. However, the complexities involved, such as time, costs, and structural modifications, often discourage clients, tenants, and occupants from undergoing a building renovation process. Textile membranes, despite their long history in various architectural applications, have only been employed in façades in the last decades. Their intrinsic properties, such as lightness and flexibility, together with rapid assembly and low maintenance make these materials particularly suitable for façade retrofitting. Therefore, they are worth exploring as a way to promote the development of lightweight and easy-to-assemble façade products that could help overcome the current limitations of building retrofitting efforts. This paper aims to establish relationships between textile membranes and potential building retrofit applications. To this end, this study builds on the categorization of traditional façade retrofit strategies and proposes a new classification for textile façade retrofit products. The methodology includes a comprehensive literature review of textile properties and characteristics, along with a thorough assessment through case studies, of membrane use in façade applications. A sequential investigation leads to the main outcome of identifying three clear pathways for the development of new textile-based façade products for building retrofit.","Façade retrofit; textile façade; membrane; innovative strategies; resilient constructions; Sustainability; lightweight structures","en","journal article","","","","","","","","","","","Architectural Technology","","",""
"uuid:29fd8dd3-454d-4e65-af70-5fa2b8dec048","http://resolver.tudelft.nl/uuid:29fd8dd3-454d-4e65-af70-5fa2b8dec048","Polarimetric Calibration of an FMCW Doppler Radar with Dual-Orthogonal Signals","Krasnov, O.A. (TU Delft Microwave Sensing, Signals & Systems); Zhang, Q. (Student TU Delft); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2024","In this paper, the full calibration chain of FMCW radar with simultaneous transmission of two orthogonally polarized orthogonal waveforms is considered. Specifically for this type of polarimetric radar, compensation of signals’ biases and equalization of the amplification gains of the parallel polarimetric channels in the receiver are jointly performed using the noise measurements. The calibrations of the absolute complex gains of the transmitter’s polarimetric channels together with complex antenna gains are done using the model-based fit of the measurements of the rotating dihedral reflector. Phase relations between polarimetric channels are treated in the Doppler domain using the unfolded velocity of the target. The performed calibration results in high-accurate measurements of the radar targets’ polarimetric scattering matrix (PSM) in the Doppler domain. All the proposed calibration steps are illustrated using real radar data.","radar polarimetry; polarimetric calibration; polarization scattering matrix measurements","en","conference paper","","","","","","","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:0012651c-dd2d-4d09-b692-9ee41cf078e3","http://resolver.tudelft.nl/uuid:0012651c-dd2d-4d09-b692-9ee41cf078e3","Nonideal compressible fluid dynamics of dense vapors and supercritical fluids.","Guardone, Alberto (Politecnico di Milano); Colonna, Piero (TU Delft Flight Performance and Propulsion); Pini, M. (TU Delft Flight Performance and Propulsion); Spinelli, Andrea (Politecnico di Milano)","","2024","The gas dynamics of single-phase nonreacting fluids whose thermodynamic states are close to vapor-liquid saturation, close to the vapor-liquid critical point, or in supercritical conditions differs quantitatively and qualitatively from the textbook gas dynamics of dilute, ideal gases. Due to nonideal fluid thermodynamic properties, unconventional gas dynamic effects are possible, including nonclassical rarefaction shock waves and the nonmonotonic variation of the Mach number along steady isentropic expansions. This review provides a comprehensive theoretical framework of the fundamentals of nonideal compressible fluid dynamics (NICFD). The relation between nonideal gas dynamics and the complexity of the fluid molecules is clarified. The theoretical, numerical, and experimental tools currently employed to investigate NICFD flows and related applications are reviewed, followed by an overview of industrial processes involving NICFD, ranging from organic Rankine and supercritical CO2 cycle power systems to supercritical processes. The future challenges facing researchers in the field are briefly outlined.","nonideal compressible fluid dynamics; nonideal thermodynamics; fundamental derivative of gas dynamics; supercritical carbon dioxide flows and power systems; organic Rankine cycle power systems; supercritical injection","en","journal article","","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:a08a993e-a57c-4bc0-8702-2148a6f1b70e","http://resolver.tudelft.nl/uuid:a08a993e-a57c-4bc0-8702-2148a6f1b70e","Fast particle-mesh code for Milgromian dynamics","Visser, P.M. (TU Delft Mathematical Physics); Eijt, S.W.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); de Nijs, J.V. (Student TU Delft)","","2024","Context. Modified Newtonian dynamics (MOND) is a promising alternative to dark matter. To further test the theory, there is a need for fluid- and particle-dynamics simulations. The force in MOND is not a direct particle-particle interaction, but derives from a potential for which a nonlinear partial differential equation (PDE) needs to be solved. Normally, this makes the problem of simulating dynamical evolution computationally expensive. Aims. We intend to develop a fast particle-mesh (PM) code for MOND (the AQUAL formalism). Methods. We transformed the nonlinear equation for MOND into a system of linear PDEs plus one algebraic equation. An iterative scheme with the fast Fourier transform (FFT) produces successively better numerical approximations. Results. The algorithm was tested for dynamical systems in MOND where analytical solutions are known: the two-body problem, a body with a circular ring, and a spherical distribution of particles in thermal equilibrium in the self-consistent potential. Conclusions. The PM code can accurately calculate the forces at subpixel scale and reproduces the analytical solutions. Four iterations are required for the potential, but when the spatial steps are small compared to the kernel width, one iteration is suffices. The use of a smoothing kernel for the accelerations is inevitable in order to eliminate the self-gravity of the point particles. Our PDE solver is 15 to 42 times as slow as a standard Poisson solver. However, the smoothing and particle propagation takes up most of the time above one particle per 10 3 pixels. The FFTs, the smoothing, and the propagation part in the code can all be parallelized.","gravitation; numerical; planets and satellites: general – planets and satellites: formation; Galaxies: kinematics and dynamics; Galaxies: formation; Cosmology; dark matter theory","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:3880f334-a1a3-43df-a825-7eaa141d2548","http://resolver.tudelft.nl/uuid:3880f334-a1a3-43df-a825-7eaa141d2548","Precipitation Doppler Spectrum Reconstruction With Gaussian Process Prior","Dash, T.K. (TU Delft Microwave Sensing, Signals & Systems); Driessen, J.N. (TU Delft Microwave Sensing, Signals & Systems); Krasnov, O.A. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2024","The challenge of reconstructing the Doppler spectrum of a precipitation-like event observed by a fast-scanning weather radar is addressed. A novel method is proposed where the echo sequence in time is assumed to be a complex Gaussian process with a known covariance structure. It is a two-step approach where the first step is the estimation of the hyperparameters of the covariance function with a maximum likelihood approach, and the second step is the reconstruction of the spectrum directly in the time or spectral domain. The proposed approach is applied to simulated data for hyper-parameter estimation performance analysis and real radar data for the complete Doppler spectrum reconstruction.","Bayesian Inference; Weather Doppler Radar","en","conference paper","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-24","","","Microwave Sensing, Signals & Systems","","",""
"uuid:512ca0f2-7b8a-45fa-9b8b-266508e77126","http://resolver.tudelft.nl/uuid:512ca0f2-7b8a-45fa-9b8b-266508e77126","How to conduct more systematic reviews of agent-based models and foster theory development: Taking stock and looking ahead","Achter, Sebastian (Hamburg University of Technology); Borit, Melania (UiT the Arctic University of Norway); Cottineau, C. (TU Delft Urban Studies); Meyer, Matthias (Hamburg University of Technology); Polhill, J. Gareth (The James Hutton Institute); Radchuk, Viktoriia (Leibniz Institute for Zoo and Wildlife Research)","","2024","Agent-based models (ABMs) are increasingly utilized in ecology and related fields, yet concerns persist regarding the lack of consideration for lessons learned from previous models. This study explores the potential of systematically conducted ABM reviews to contribute to cumulative science and theory development by synthesizing individual ABM findings more effectively. We are conducting a meta-review of ABM reviews to assess current practices, compare them to systematic literature review (SLR) literature recommendations, and evaluate their engagement with theory and theory development. Our analysis of the ecology and social science sample reveals that many reviews are not conducted systematically and lack transparency. The analysis step of SLRs holds significant potential to advance theory development. Reviews primarily focus on model design, while other avenues of theory development receive less attention. Our findings suggest ways to improve current practices and may guide future ABM reviews via benchmarks for methodological decisions and dimensions for advancing theory development.","Systematic literature review; Literature review; Agent-based modelling; Model design; Theory development; Cumulative science","en","journal article","","","","","","","","","","","Urban Studies","","",""
"uuid:02eaf4bb-db40-473a-91f7-02fe3dd24a08","http://resolver.tudelft.nl/uuid:02eaf4bb-db40-473a-91f7-02fe3dd24a08","Stability Analysis for Incremental Adaptive Dynamic Programming with Approximation Errors","Li, Y. (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation)","","2024","This paper provides a convergence and stability analysis of the incremental value iteration algorithm under the influence of various errors. Incremental control is firstly used to linearize the continuous-time nonlinear system, recursive least squares (RLS) identification is then introduced to identify the incremental model online. Based on the incremental model, the value iteration algorithm is used to design an optimal adaptive controller, with an analytical optimal control law. Moreover, the convergence of the developed incremental value iteration algorithm is proved. The stability of the controller is analyzed using Lyapunov stability theory. Finally, a flight control simulation verifies the robustness of the controller to various initial conditions, as well as adaptation to actuator faults.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-06","","","Control & Simulation","","",""
"uuid:d0202570-790a-4a6b-99df-e73bb0edcebc","http://resolver.tudelft.nl/uuid:d0202570-790a-4a6b-99df-e73bb0edcebc","Effect of stacking fault energy on the thickness and density of annealing twins in recrystallized FCC medium and high-entropy alloys","Schneider, Mike (Ruhr-Universität Bochum; PSL Research University); Couzinié, Jean Philippe (Université Paris-Est Créteil); Shalabi, Amin (Ruhr-Universität Bochum); Ibrahimkhel, Farhad (Ruhr-Universität Bochum); Ferrari, A. (TU Delft Team Marcel Sluiter); Körmann, F.H.W. (TU Delft Team Marcel Sluiter; Max-Planck-Institut für Eisenforschung; Bundesanstalt für Materialforschung und -prüfung (BAM)); Laplanche, Guillaume (Ruhr-Universität Bochum)","","2024","This work aims to predict the microstructure of recrystallized medium and high-entropy alloys (MEAs and HEAs) with a face-centered cubic structure, in particular the density of annealing twins and their thickness. Eight MEAs and five HEAs from the Cr-Mn-Fe-Co-Ni system are considered, which have been cast, homogenized, cold-worked and recrystallized to obtain different grain sizes. This work thus provides a database that could be used for data mining to take twin boundary engineering for alloy development to the next level. Since the stacking fault energy is known to strongly affect recrystallized microstructures, the latter was determined at 293 K using the weak beam dark-field technique and compared with ab initio simulations, which additionally allowed to calculate its temperature dependence. Finally, we show that all these data can be rationalized based on theories and empirical relationships that were proposed for pure metals and binary Cu-based alloys.","CoCrFeMnNi HEAs and MEAs; Electron backscatter diffraction; Grain boundary engineering; Recrystallization; Transmission electron microscopy (TEM)","en","journal article","","","","","","","","","","","Team Marcel Sluiter","","",""
"uuid:0e02777d-c09c-43ed-b634-6f8d02f8b9b5","http://resolver.tudelft.nl/uuid:0e02777d-c09c-43ed-b634-6f8d02f8b9b5","Optical STEM detection for scanning electron microscopy","Kievits, A.J. (TU Delft ImPhys/Hoogenboom group); Duinkerken, B. H.Peter (University Medical Center Groningen); Fermie, Job (Delmic BV); Lane, R. (TU Delft ImPhys/Hoogenboom group); Giepmans, Ben N.G. (University Medical Center Groningen); Hoogenboom, J.P. (TU Delft ImPhys/Hoogenboom group)","","2024","Recent advances in electron microscopy techniques have led to a significant scale up in volumetric imaging of biological tissue. The throughput of electron microscopes, however, remains a limiting factor for the volume that can be imaged in high resolution within reasonable time. Faster detection methods will improve throughput. Here, we have characterized and benchmarked a novel detection technique for scanning electron microscopy: optical scanning transmission electron microscopy (OSTEM). A qualitative and quantitative comparison was performed between OSTEM, secondary and backscattered electron detection and annular dark field detection in scanning transmission electron microscopy. Our analysis shows that OSTEM produces images similar to backscattered electron detection in terms of contrast, resolution and signal-to-noise ratio. OSTEM can complement large scale imaging with (scanning) transmission electron microscopy and has the potential to speed up imaging in single-beam scanning electron microscope.","Electron detection; Instrumentation development; Scanning electron microscopy; Scanning transmission electron microscopy; Volume electron microscopy","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-30","","","ImPhys/Hoogenboom group","","",""
"uuid:226bbaa0-e785-42ce-8e44-501c0d7b1330","http://resolver.tudelft.nl/uuid:226bbaa0-e785-42ce-8e44-501c0d7b1330","Hot air recirculation enlarges efficient operating window of reversible solid oxide cell systems: A thermodynamic study of energy storage using ammonia","Amladi, Amogh (Rijksuniversiteit Groningen; Student TU Delft); Venkataraman, V. (TU Delft Energy Technology; AVL List GmbH); Woudstra, T. (TU Delft Process and Energy; Rijksuniversiteit Groningen); Aravind, P.V. (TU Delft Energy Technology; Rijksuniversiteit Groningen)","","2024","Energy storage is vital for the energy transition, enabling reliable power grids based on intermittent renewables. Reversible solid oxide cell (rSOC) technology is promising for seasonal energy storage. The novel finding from this work is that optimised air recirculation for rSOC in endothermic electrolyser mode leads to efficiency being nearly independent of current density. Thereby the operating region of highest efficiency is expanded from the thermoneutral point to the entire endothermic region, leading to highly efficient part-load operation. Air recirculation increases fuel cell mode efficiency too, particularly at higher loads. This widens the efficient operating window in both modes. These findings emerge from a thermodynamic study of an rSOC-based energy storage system with ammonia as fuel. A process design is developed and optimised for efficiency, supported with detailed exergy analysis. First, ammonia synthesis subsystem integrated with the rSOC system in electrolyser mode is optimised. Second, rSOC outlet air recirculation is optimised for high system efficiency. Finally, rSOC operating points are optimised for highest round-trip efficiency. We find the least exergy destruction for the ammonia synthesis subsystem at 170 bar synthesis pressure and 30 °C condensation temperature (without needing refrigeration). The overall system achieves round-trip efficiencies up to 60.3%.","Air recirculation; Ammonia; Energy storage; Exergy; Fuel cell; Reversible solid oxide cell","en","journal article","","","","","","","","","","Process and Energy","Energy Technology","","",""
"uuid:b4236ba2-0fea-4213-be35-0545f219fbaa","http://resolver.tudelft.nl/uuid:b4236ba2-0fea-4213-be35-0545f219fbaa","Damping of 3D-printed polymer microbeam resonators","de Winter, Jikke (Student TU Delft); Manzaneque Garcia, T. (TU Delft Electronic Instrumentation); Ghatkesar, M.K. (TU Delft Micro and Nano Engineering)","","2024","The emerging high-resolution 3D printing technique called two-photon polymerization (2PP) enables to print devices bottom-up rapidly, contrary to the top-down lithography-based fabrication methods. In this work, various polymer microbeams are 3D printed and their resonant characteristics are analyzed to understand the origin of damping. The 2PP printed polymer resonators have shown less damping than other polymer devices reported earlier, with tensile-stressed clamped-clamped beams reaching a record quality factor of 1819. The resonant energy loss was dominant by bulk friction damping. These results pave the path towards using 3D printed microresonators as mass sensors with improved design and fabrication flexibility.","2PP printing; 3D printing; additive manufacturing; damping; microresonator; polymer microbeam; quality factor","en","journal article","","","","","","","","","","","Electronic Instrumentation","","",""
"uuid:15f8e22d-492b-4922-96fb-6cb7f9dac406","http://resolver.tudelft.nl/uuid:15f8e22d-492b-4922-96fb-6cb7f9dac406","An in-depth comparison of linear and non-linear joint embedding methods for bulk and single-cell multi-omics","Makrodimitris, S. (TU Delft Pattern Recognition and Bioinformatics; Erasmus MC); Pronk, I.B. (TU Delft Pattern Recognition and Bioinformatics); Abdelaal, T.R.M. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center); Reinders, M.J.T. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center)","","2024","Multi-omic analyses are necessary to understand the complex biological processes taking place at the tissue and cell level, but also to make reliable predictions about, for example, disease outcome. Several linear methods exist that create a joint embedding using paired information per sample, but recently there has been a rise in the popularity of neural architectures that embed paired -omics into the same non-linear manifold. This work describes a head-to-head comparison of linear and non-linear joint embedding methods using both bulk and single-cell multi-modal datasets. We found that non-linear methods have a clear advantage with respect to linear ones for missing modality imputation. Performance comparisons in the downstream tasks of survival analysis for bulk tumor data and cell type classification for single-cell data lead to the following insights: First, concatenating the principal components of each modality is a competitive baseline and hard to beat if all modalities are available at test time. However, if we only have one modality available at test time, training a predictive model on the joint space of that modality can lead to performance improvements with respect to just using the unimodal principal components. Second, -omic profiles imputed by neural joint embedding methods are realistic enough to be used by a classifier trained on real data with limited performance drops. Taken together, our comparisons give hints to which joint embedding to use for which downstream task. Overall, product-of-experts performed well in most tasks and was reasonably fast, while early integration (concatenation) of modalities did quite poorly.","dimensionality reduction; joint embedding; multi-omics; neural networks","en","review","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:2c9e2c71-b497-461c-9df6-5375c158983e","http://resolver.tudelft.nl/uuid:2c9e2c71-b497-461c-9df6-5375c158983e","Semi-empirical calibration of remote microphone probes using Bayesian inference","Moriaux, Olivier (von Karman Institute for Fluid Dynamics); Zamponi, R. (TU Delft Wind Energy; von Karman Institute for Fluid Dynamics); Schram, Christophe (von Karman Institute for Fluid Dynamics)","","2024","The empirical calibration of remote microphone probes (RMP), used to acquire wall-pressure fluctuations, can introduce spurious resonance into the sensor transfer function due to the difference in the pressure field inside the calibrator geometry over multiple calibration steps. Such spurious resonance subsequently propagates into the unsteady-pressure data at which the calibration is applied, hindering the accuracy of the measurements. Current post-processing methods for tackling these issues are often manual and strongly dependent on the operator's expertise. In this study, we propose an original semi-empirical calibration method to remove spurious resonance in a less operator-reliant manner. The approach is based on fitting an existing analytical fluid-dynamical model for the propagation of pressure waves in the probe to the empirical calibration data using Bayesian inference. The proposed method is successfully applied to three datasets, from a simple probe recessed behind a pinhole to a more complex branching RMP. For all the configurations, spurious resonance is eliminated from the transfer function with a strongly reduced impact of the operator intervention while retaining the resonant features that are characteristic of the RMP. The affected frequency bands are then replaced using the underlying physical model. In this way, the detrimental impact of spurious resonance is removed from the measured wall-pressure spectra. Furthermore, the RMP parameters retrieved by the fit can also be used as inputs to corrective models, specifically to account for averaging effects due to the probe sensing area or for the impact of grazing flow or temperature variations on the transfer function.","Bayesian inference; Microphone calibration; Remote microphone probe; Wall-pressure fluctuations","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:fb2f1a1a-7550-4d59-ba3b-6ef61ccab032","http://resolver.tudelft.nl/uuid:fb2f1a1a-7550-4d59-ba3b-6ef61ccab032","Identifying patterns and recommendations of and for sustainable open data initiatives: A benchmarking-driven analysis of open government data initiatives among European countries","Lnenicka, Martin (University of Pardubice); Nikiforova, Anastasija (University of Tartu); Luterek, Mariusz (University of Warsaw); Milic, Petar (University of Pristina); Rudmark, Daniel (University of Gothenburg; Swedish National Road and Transport Research Institute); Neumaier, Sebastian (St. Pölten University of Applied Sciences); Santoro, C. (TU Delft Information and Communication Technology; Katholieke Universiteit Leuven); Casiano Flores, Cesar (University of Twente); Janssen, M.F.W.H.A. (TU Delft Engineering, Systems and Services); Rodríguez Bolívar, Manuel Pedro (Universidad de Granada)","","2024","Open government and open (government) data are seen as tools to create new opportunities, eliminate or at least reduce information inequalities and improve public services. More than a decade of these efforts has provided much experience, practices, and perspectives to learn how to better deal with them. This paper focuses on benchmarking of open data initiatives over the years and attempts to identify patterns observed among European countries that could lead to disparities in the development, growth, and sustainability of open data ecosystems. To do this, we studied benchmarks and indices published over the last years (57 editions of 8 artifacts) and conducted a comparative case study of eight European countries, identifying patterns among them considering different potentially relevant contexts such as e-government, open government data, open data indices and rankings, and others relevant for the country under consideration. Using a Delphi method, we reached a consensus within a panel of experts and validated a final list of 94 patterns, including their frequency of occurrence among studied countries and their effects on the respective countries. Finally, we took a closer look at the developments in identified contexts over the years and defined 21 recommendations for more resilient and sustainable open government data initiatives and ecosystems and future steps in this area.","Benchmarking; Cluster analysis; Delphi method; E-government; Open data; Open data initiative; Pattern","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-08","","Engineering, Systems and Services","Information and Communication Technology","","",""
"uuid:2a3ae1b0-2d1e-4e8b-bb6d-a019edf14e23","http://resolver.tudelft.nl/uuid:2a3ae1b0-2d1e-4e8b-bb6d-a019edf14e23","Prioritize carbon pricing over fossil-fuel subsidy reform","van den Bergh, Jeroen (Universitat Autònoma de Barcelona; Catalan Institution for Research and Advanced Studies (ICREA); Vrije Universiteit Amsterdam); van Beers, Cees (TU Delft Economics of Technology and Innovation); King, Lewis C. (Universitat Autònoma de Barcelona)","","2024","While many climate activist groups enthusiastically advocate for the removal of fossil-fuel subsidies, we argue that this overstates both the climate effectiveness and political feasibility of such a strategy. Through synthesizing information from various global studies, we show that subsidies contribute to a relatively small portion of climate change and local externality problems, likely accounting for around 1%. We further argue that reform of fossil-fuel subsidies is hampered by various political and social factors, more so than the diffusion of carbon pricing. Based on these results, we argue that the far greater problem of unpriced externalities warrants a redirection or expansion of the enthusiasm for subsidy reform toward carbon pricing. This makes sense also as subsidy reform and carbon pricing essentially represent two sides of the same coin since both contribute to climate mitigation by raising fossil-fuel prices.","Environmental policy; Global change","en","review","","","","","","","","","","","Economics of Technology and Innovation","","",""
"uuid:e1b419c1-b48e-4462-a5ab-8b39f951e6f4","http://resolver.tudelft.nl/uuid:e1b419c1-b48e-4462-a5ab-8b39f951e6f4","Bubbles and Broth: A review on the impact of broth composition on bubble column bioreactor hydrodynamics","Volger, R. (TU Delft BT/Bioprocess Engineering); Puiman, L. (TU Delft BT/Bioprocess Engineering); Haringa, C. (TU Delft BT/Bioprocess Engineering)","","2024","The growing global population and heightened concern for climate change leads to increased interest in utilizing microbial fermentations to replace polluting production processes for e.g., plastics, fuels, and animal proteins. Computational fluid dynamics (CFD) is a valuable tool for accelerating the scale-up and optimization of large-scale bioprocesses. However, the design correlations underlying most of these CFD models are validated with air-water systems, not accounting for the distinct hydrodynamic properties of microbial fermentation broth. In this review, we provide an extensive overview of the current understanding of how various biotechnologically relevant solutes impact the hydrodynamics of bubble columns. We examine the effects of components found in fermentation broths, including salts, surfactants, viscoelastic solutes, alcohols, acids, ketones, sugars, biomass, and proteins, on mass transfer, bubble formation, bubble interactions, and flow regime transitions. These components all exhibit unique effects, yet their combined influences remain poorly understood. Future research should prioritize identifying the concentration at which coalescence inhibition occurs for different compounds, especially in mixtures, and exploring the role of proteins in bubble column hydrodynamics from micro- to macroscale.","Bioprocesses; Bioreactor scale-up; Bubble columns; Hydrodynamics","en","review","","","","","","","","","","","BT/Bioprocess Engineering","","",""
"uuid:06377eef-1dda-41aa-9bbe-d17013577cc1","http://resolver.tudelft.nl/uuid:06377eef-1dda-41aa-9bbe-d17013577cc1","Integrated design optimization method for novel vapour-compression-cycle-based environmental control systems","Ascione, F. (TU Delft Flight Performance and Propulsion); Colonna, Piero (TU Delft Flight Performance and Propulsion); de Servi, C.M. (TU Delft Flight Performance and Propulsion; Flemish Institute for Technological Research)","","2024","The aircraft Environmental Control System (ECS) is the primary consumer of non-propulsive power at cruise conditions, hence, its performance optimization is crucial for the reduction of specific fuel consumption. A novel integrated system design optimization method is presented: thermodynamic cycle, component sizing and working fluid are taken into account simultaneously. This method was applied to the ECS of large rotorcraft based on a Vapour Compression Cycle system electrically driven by a high-speed centrifugal compressor. Steady-state and lumped parameter system component models have been developed using the Modelica acausal modelling language. The optimization design framework consists of an in-house code, featuring a Python-Modelica interface. The study case refers to a critical operating condition: the helicopter is on the ground during a hot and humid day. The working fluid is R-134a. The multi-objective optimization targets the maximization of the system efficiency and the minimization of system weight. The results show that more efficient systems can be designed only with heavier components. The design feasibility of high-speed centrifugal compressors is demonstrated. The advantage of an integrated system design optimization framework for complex energy systems is proved, allowing for the analysis of the impact of both component design and working fluid on system performance.","Environmental control system; Helicopter/aircraft auxiliary systems; High-speed centrifugal compressor; Integrated design optimization; More electric aircraft/rotorcraft; Vapour compression cycle","en","journal article","","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:33b5a5a9-4302-48f9-b804-a6f5a365af77","http://resolver.tudelft.nl/uuid:33b5a5a9-4302-48f9-b804-a6f5a365af77","The Effect of Psychological Scarcity on Health Decisions of Rural Residents in China: Preliminary Results","Zhu, H. (TU Delft Applied Ergonomics and Design; Loughborough University); Liu, E. (Southwest Forestry University); You, Fangzhou (Loughborough University); de Bont, Cees (Loughborough University); Gruber, Thorsten (Loughborough University); Dong, Hua (Brunel University); Melles, M. (TU Delft Applied Ergonomics and Design)","Melles, Marijke (editor)","2024","Economic studies have shown that living in poverty may produce a subjective feeling of scarcity, which affects people's cognitive functions and decision-making. Understanding this mechanism could inform healthcare designers on designing inclusive health interventions by considering the psychological scarcity and limited cognitive resources of impoverished individuals. We conducted a psychological experiment to test the impact of psychological scarcity on cognitive function and health decisions of rural residents in China. We randomly assign participants to two financial scenarios (hard vs. easy) with the technique of priming to induce their immediate financial worries. Then we measure cognitive function using Raven’s Progressive Matrices and uncover their decision-making priorities with a budget allocation task. 301 participants finished the study and 264 were included in the main analysis. The results show that both immediate financial worries and cumulative poverty have negative effects on participants’ cognitive performance. Responses to scarcity could lead to attentional focus on limited resources, thereby neglecting long-term health consequences, particularly for the lower income group. Based on the findings, we suggest a number of human factors design considerations that are critical to successful healthcare design.","Cognitive function; Health decision-making; Health intervention; Psychological scarcity","en","book chapter","Springer Nature","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-05","","","Applied Ergonomics and Design","","",""
"uuid:752ccb09-e90a-4ffe-a9ac-f94905118023","http://resolver.tudelft.nl/uuid:752ccb09-e90a-4ffe-a9ac-f94905118023","Machine learning in process systems engineering: Challenges and opportunities","Daoutidis, Prodromos (University of Minnesota Twin Cities); Lee, Jay H. (University of Southern California); Rangarajan, Srinivas (Lehigh University); Chiang, Leo (The Dow Chemical Company); Gopaluni, Bhushan (University of British Columbia); Schweidtmann, A.M. (TU Delft ChemE/Product and Process Engineering); Harjunkoski, Iiro (Aalto University); Mercangöz, Mehmet (Imperial College London); Mesbah, Ali (University of California)","","2024","This “white paper” is a concise perspective of the potential of machine learning in the process systems engineering (PSE) domain, based on a session during FIPSE 5, held in Crete, Greece, June 27–29, 2022. The session included two invited talks and three short contributed presentations followed by extensive discussions. This paper does not intend to provide a comprehensive review on the subject or a detailed exposition of the discussions; instead its aim is to distill the main points of the discussions and talks, and in doing so, highlight open problems and directions for future research. The general conclusion from the session was that machine learning can have a transformational impact on the PSE domain enabling new discoveries and innovations, but research is needed to develop domain-specific techniques for problems in molecular/material design, data analytics, optimization, and control.","Control; Machine learning; Modeling; Molecule discovery; Optimization; Process monitoring","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-22","","","ChemE/Product and Process Engineering","","",""
"uuid:882cb88b-5341-45df-ab4f-a8a19fc399f2","http://resolver.tudelft.nl/uuid:882cb88b-5341-45df-ab4f-a8a19fc399f2","Data-driven product-process optimization of N-isopropylacrylamide microgel flow-synthesis","Kaven, Luise F. (Rheinisch-Westfälische Technische Hochschule); Schweidtmann, A.M. (TU Delft ChemE/Product and Process Engineering); Keil, Jan (Rheinisch-Westfälische Technische Hochschule); Israel, Jana (Rheinisch-Westfälische Technische Hochschule); Wolter, Nadja (DWI-Leibniz Institute for Interactive Materials; Rheinisch-Westfälische Technische Hochschule); Mitsos, Alexander (Rheinisch-Westfälische Technische Hochschule)","","2024","Microgels are cross-linked, colloidal polymer networks with great potential for stimuli-response release in drug-delivery applications, as their small size allows them to pass human cell boundaries. For applications with specified requirements regarding size, producing tailored microgels in a continuous flow reactor is advantageous because the microgel properties can be controlled tightly. However, no fully-specified mechanistic models are available for continuous microgel synthesis, as the physical properties of the included components are only studied partly. To address this gap and accelerate tailor-made microgel development, we propose a data-driven optimization in a hardware-in-the-loop approach to efficiently synthesize microgels with defined sizes. We optimize the synthesis regarding conflicting objectives (maximum production efficiency, minimum energy consumption, and the desired microgel radius) by applying Bayesian optimization via the solver “Thompson sampling efficient multi-objective optimization” (TS-EMO). We validate the optimization using the deterministic global solver “McCormick-based Algorithm for mixed-integer Nonlinear Global Optimization” (MAiNGO) and verify three computed Pareto optimal solutions via experiments. The proposed framework can be applied to other desired microgel properties and reactor setups and has the potential of efficient development by minimizing number of experiments and modeling effort needed.","Bayesian optimization; Flow-chemistry; Microgel synthesis; Product-process optimization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-01","","","ChemE/Product and Process Engineering","","",""
"uuid:8509576d-038d-475b-a89d-f913de6ec826","http://resolver.tudelft.nl/uuid:8509576d-038d-475b-a89d-f913de6ec826","Investigating the influence of pigmentation on the electrolyte transport properties of organic coatings using ORP-EIS","Madelat, Negin (Vrije Universiteit Brussel); Wouters, Benny (Vrije Universiteit Brussel); Visser, Peter (Akzo Nobel); Jiryaeisharahi, Zahra (Vrije Universiteit Brussel); Marcoen, Kristof (Vrije Universiteit Brussel); Abrahami, S.T. (TU Delft Team Shoshan Abrahami); Hubin, Annick (Vrije Universiteit Brussel); Terryn, H.A. (Vrije Universiteit Brussel); Hauffman, Tom (Vrije Universiteit Brussel)","","2024","In this work, the correlation between electrolyte transport properties and the variation of pigment volume concentration (PVC) in a series of organic coatings is explored. Using an odd random phase electrochemical impedance spectroscopy (ORP-EIS) approach, the diffusion of ions independent from water take-up is analysed. A higher PVC resulted in a more homogeneous coating morphology, which could be associated with a faster diffusion of ions following a Fickian regime and enhanced water uptake. In the case of lower pigment loading, the obtained heterogenous morphology of the coating introduced new challenges to the physical interpretation of the proposed electrochemical equivalent circuit.","GDOES; Ion diffusion; Organic coating; ORP-EIS; Water uptake","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-22","","","Team Shoshan Abrahami","","",""
"uuid:2d672146-33ea-4b66-b9a4-c75ae9090267","http://resolver.tudelft.nl/uuid:2d672146-33ea-4b66-b9a4-c75ae9090267","On the use of filament-based free wake panel methods for preliminary design of propeller-wing configurations","Pinto Ribeiro, A. (TU Delft Wind Energy); Ferreira, Carlos (TU Delft Wind Energy); Casalino, D. (TU Delft Wind Energy)","","2024","With distributed propulsion and electric vertical take-off and landing aircraft on the rise, fast and accurate methods to simulate propeller slipstreams and their interaction with aircraft components are needed. In this work, we compare results obtained with a filament-based free wake panel method to experimental and previously validated numerical data. In particular, we study a propeller-wing configuration at zero angle of attack and the aerodynamics of the blade-resolved slipstream interaction with the wing. We use a prescribed wake on the wing and a free wake on the propeller, which greatly accelerate the computations. Results indicate that, while forces are overpredicted due to the inviscid nature of the panel method, the free wake is able to capture the slipstream deformation and shearing with remarkable success. We find that a filament-based free wake panel method can be a useful tool for propeller-wing interaction in preliminary aircraft design.","Aerodynamics; eVTOL; Slipstream deformation; UAV; Wake interactions","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:0effe8fb-f5c3-4aeb-b4cf-baf7bfad2ec2","http://resolver.tudelft.nl/uuid:0effe8fb-f5c3-4aeb-b4cf-baf7bfad2ec2","A proposal for similitude in characterizing fatigue delamination behavior with fibre bridging of carbon-fibre reinforced polymer composites","Yao, Liaojun (Harbin Institute of Technology; Aircraft Strength Research Institute); Chuai, Mingyue (Harbin Institute of Technology); Lyu, Zhangming (Harbin Institute of Technology); Chen, Xiangming (Aircraft Strength Research Institute); Guo, Licheng (Harbin Institute of Technology); Alderliesten, R.C. (TU Delft Structural Integrity & Composites)","","2024","Methods based on fracture mechanics have been widely used in fatigue delamination growth (FDG) characterization of composite laminates. These methods are based on the similitude hypothesis. It is therefore important to have appropriate parameters to well represent the similitude, which is useful for fatigue delamination test standard development aimed by Technical Committee 4 of the European Structural Integrity Society (ESIS TC4) and the ISO/TC61/SC13. In the present study, discussions on similitude parameters for fibre-bridged fatigue delamination interpretation have been conducted via fatigue data with fibre bridging at different R-ratios. The results clearly demonstrate that the strain energy release rate (SERR) indeed applied around the crack front, rather than the total applied SERR, should be employed to represent the similitude for FDG interpretation with large-scale fibre bridging. Particularly, the use of Δ√Gtip can well determine fibre-bridged delamination behavior of a given R-ratio, but it is not valid for FDG at different R-ratios in accordance with the similitude principles. A new similitude parameter, in terms of both Δ√Gtip and the maximum SERR Gmax_tip, was therefore proposed to appropriately represent FDG behavior with fibre bridging at different R-ratios. This study can not only provide database, but also give important insights for the development of mode I fatigue delamination test standard of composite laminates.","Composite laminates; Fatigue delamination; Fibre bridging; Similitude; Stress ratio","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-03","","","Structural Integrity & Composites","","",""
"uuid:640c0f3e-60c4-4736-ae08-352bef953637","http://resolver.tudelft.nl/uuid:640c0f3e-60c4-4736-ae08-352bef953637","On the post-impact fatigue behavior and theoretical life prediction of CF/PEEK-titanium hybrid laminates using an energy dissipation approach","Ji, C. (TU Delft Structural Integrity & Composites; Harbin Institute of Technology); Hu, Jiqiang (Harbin Institute of Technology); Alderliesten, R.C. (TU Delft Structural Integrity & Composites); Yang, Jinchuan (Harbin Institute of Technology); Zhou, Zhengong (Harbin Institute of Technology); Sun, Yuguo (Harbin Institute of Technology); Wang, Bing (Harbin Institute of Technology)","","2024","This paper aims to illustrate the effect of the impact damage on fatigue behavior of CF/PEEK-titanium hybrid laminates. To achieve this end, a fatigue life model was proposed to predict the S–N curves of the laminates at various initial impact energy levels and stress ratios based on the energy dissipation approach. The energy dissipation behavior of the laminates during fatigue loading under different experimental conditions was analyzed through a large amount of post-impact fatigue tests, and the correlation between the initial impact damage and the total fatigue dissipation energy was determined. The full-field axial strain distribution of the titanium layer on the impacted side of the laminate was characterized in terms of initial impact energy level and maximum stress using digital image correlation, and then the post-impact fatigue failure mechanism of CF/PEEK-Ti hybrid laminates was summarized. Finally, the validity of the proposed model was verified by fatigue tests under other conditions of stress ratio and impact energy level. It is worth mentioning that the proposed model is also applicable to other types of FMLs, and can accurately predict the residual fatigue life of laminates after impact with only one set of S–N curve data.","Energy dissipation approach; Fiber metal laminates; Life prediction; Post-impact fatigue behavior","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-03","","","Structural Integrity & Composites","","",""
"uuid:b58a1cfb-28b0-4faa-8906-43325f202bdf","http://resolver.tudelft.nl/uuid:b58a1cfb-28b0-4faa-8906-43325f202bdf","Molecular dynamics simulations on mechanical behaviors of sintered nanocopper in power electronics packaging","Luo, Runding (Fudan University); Hu, D. (TU Delft Electronic Components, Technology and Materials); Qian, Cheng (Fudan University); Liu, Xu (Fudan University); Fan, Xuejun (Lamar University College of Engineering); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials; Fudan University); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University)","","2024","Nano-metal materials have received considerable attention because of their promising performance in wide bandgap semiconductor packaging. In this study, molecular dynamics (MD) simulation was performed to simulate the nano-Cu sintering mechanism and the subsequent mechanical behaviors. Hybrid sintering, comprising nanosphere (NS) and nanoflake (NF), was performed at temperatures from 500 to 650 K. Furthermore, shear and tensile simulations were conducted with constant strain rates on the sintered structure at multiple temperatures. Subsequently, the extracted mechanical properties were correlated with the sintering behavior. The results revealed that the mechanical properties of the nano-Cu sintered structure could be improved by tuning material composition and increasing the sintering temperature. We established a relationship between the sintered microstructure and mechanical response. The shear modulus and shear strength of the sintered structure with NF particles increased to 41.20 and 3.51 GPa respectively. Furthermore, the elastic modulus increased to 55.60, and the tensile strength increased to 4.88 GPa. This result provides insights into the preparation phase of nano-Cu paste for sintering technology.","Molecular dynamics (MD) simulation; Nano-Cu sintering; Nanoflake; Shear simulation; Tensile simulation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-03","","","Electronic Components, Technology and Materials","","",""
"uuid:50d362da-1302-45a9-9bde-ce8ae5e71677","http://resolver.tudelft.nl/uuid:50d362da-1302-45a9-9bde-ce8ae5e71677","Enhancing real-time nonintrusive occupancy estimation in buildings via knowledge fusion network","Lu, C.J. (TU Delft Environmental & Climate Design; Guangdong University of Technology)","","2024","Real-time nonintrusive occupancy estimation can maximize the use of existing sensors to infer occupant information in buildings with the advantages of fewer privacy concerns and fewer extra device costs. Recently, many deep learning architectures have proven effective in estimating occupancy directly from raw sensor data. However, some handcrafted features manually extracted from statistical and temporal domains might convey additional information for occupancy estimation. In this study, a novel knowledge fusion network for nonintrusive occupancy estimation is proposed to integrate knowledge from two streams, i.e. automatic knowledge stream from a deep learning architecture and handcrafted knowledge stream from manual feature engineering. Moreover, four different fusion modules are investigated to optimize the design of the fusion network. To verify the effectiveness of the proposed network, experiments are conducted in a dataset from the ASHRAE Global Occupant Behavior Database, which is collected from an office space with records of indoor environment parameters, occupant-building interactions, and contextual information. The results demonstrate the superiority of the proposed fusion network, which outperforms five representative algorithms. Furthermore, the ablation study underscores the benefits of knowledge fusion and occupant-building interaction information, showing that the proposed fusion network can enhance the occupancy estimation accuracy by 3.47 % to 9.24 %.","Deep learning; Network fusion; Nonintrusive sensing; Occupancy estimation; Smart buildings","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:0af8a03d-a9ab-4a6c-96e7-33a8e982bd1f","http://resolver.tudelft.nl/uuid:0af8a03d-a9ab-4a6c-96e7-33a8e982bd1f","A metamaterial-based interface for the structural resonance shielding of impact-driven offshore monopiles","Azevedo Vasconcelos, A.C. (TU Delft Transport Engineering and Logistics); Valiya Valappil, S. (TU Delft Computational Design and Mechanics); Schott, D.L. (TU Delft Transport Engineering and Logistics); Jovanova, J. (TU Delft Transport Engineering and Logistics); Aragon, A.M. (TU Delft Computational Design and Mechanics)","","2024","Underwater noise resulting from the monopile driving process can cause severe damage to marine wildlife, such as hearing injury, behavioral disturbance, or even death. Although current noise-attenuation techniques used in this process have shown a significant noise reduction at high frequency ranges, mitigating low-frequency noise is still extremely challenging. To address the problem, here we propose an elastic metamaterial-based structure composed of single-phase resonant structures. The proposed structure, which we call a meta-interface, is introduced between the monopile and the hammer and is used to remove energy from the input signal associated with high noise levels. To that end, we first identify the frequency ranges associated with high sound pressure levels, which were shown to be related to the monopile's eigenmodes. Then we design the meta-interface's periodic unit cells so that the elastic/acoustic waves at identified frequency ranges are attenuated. A meta-interface is then realized by replicating the unit cell along the monopile wall (matching the thickness) to form a ring-shaped layer, and then by stacking up these concentric layers. A frequency analysis of the pile driving system with the meta-interface shows that the new noise levels attain a significant attenuation in frequency ranges lower than 1000Hz. This demonstrates a novel solution for the low-frequency underwater noise issue during the hammering of offshore monopiles.","Acoustic/elastic metamaterials; Noise attenuation; Resonance shielding; Single-phase unit cell","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:21aaa189-e80d-42d9-b332-28ba3e4236af","http://resolver.tudelft.nl/uuid:21aaa189-e80d-42d9-b332-28ba3e4236af","Microstructural stability of secondary phases in an ODS ferritic steel after thermal aging at 873 K","Oñoro, M. (Carlos III University of Madrid); de Castro, V. (Carlos III University of Madrid); Leguey, T. (Carlos III University of Madrid); Pöpperlová, J. (Rheinisch-Westfälische Technische Hochschule); Huizenga, R.M. (TU Delft Team Amarante Bottger); Auger, M. A. (Carlos III University of Madrid)","","2024","An oxide dispersion strengthened (ODS) steel with nominal composition Fe–14Cr–2W–0.4Ti–0.3Y2O3 (wt%) has been manufactured by mechanical alloying of pre-alloyed powders with nanosized Y2O3, compacted by hot isostatic pressing and hot cross rolled. In order to evaluate the long-term thermal resistance of the alloy, it has been subjected to 2000 h of thermal aging at 873 K, which is a relevant temperature for nuclear reactor applications. A thermodynamic equilibrium simulation indicates the precipitation of Laves phase under the aging parameters used. This prediction is confirmed from the detailed multi-technique characterization performed. Before aging, Ti-rich oxides, Cr-W-rich precipitates (M23C6 type) and a homogeneous Y-rich nanoprecipitate dispersion are observed. After aging, some W-rich precipitates are identified as Laves phase, while M23C6 carbides, Ti-rich oxides and Y-rich nanoprecipitates remain stable. Mechanical characterization performed in a previous research showed higher hardness, a loss of total elongation and a slight shift of the ductile-to-brittle transition temperature (DBTT) towards a higher value after aging, with similar strength values before and after the long-term thermal treatment. These changes can be due to the redistribution of precipitates together with the Laves phase formation. The mechanical properties not being dramatically affected seem to be due to the observed stability of Y-rich nanoprecipitates distribution.","Aging; APT; Laves phase; Nanoparticles; ODS steel; TEM","en","journal article","","","","","","","","","","","Team Amarante Bottger","","",""
"uuid:0b60e20e-0a0a-476f-8e36-d09db39a28bd","http://resolver.tudelft.nl/uuid:0b60e20e-0a0a-476f-8e36-d09db39a28bd","Microscopic insights into poly- and mono-crystalline methane hydrate dissociation in Na-montmorillonite pores at static and dynamic fluid conditions","Fang, B. (China University of Geosciences, Wuhan); Lü, Tao (China University of Geosciences, Wuhan); Li, Wei (China University of Geosciences, Wuhan); Moultos, O. (TU Delft Engineering Thermodynamics); Vlugt, T.J.H. (TU Delft Engineering Thermodynamics); Ning, Fulong (China University of Geosciences, Wuhan)","","2024","Knowledge on the kinetics of gas hydrate dissociation in clay pores at static and dynamic fluid conditions is a fundamental scientific issue for improving gas production efficiency from hydrate deposits using thermal stimulation and depressurization respectively. Here, molecular dynamics simulations were used to investigate poly- and mono-crystalline methane hydrates in Na-montmorillonite clay nanopores. Simulation results show that hydrate dissociation is highly sensitive to temperature and pressure gradients, but their effects differ. Temperature changes increase thermal instability of water and gas molecules, leading to layer-by-layer dissociation from the outer surface. Under flow conditions, laminar flow predominates in nano-pores, and non-Darcy flow occurs due to clay-fluid interactions. Viscous flow disrupts hydrogen bonding at the hydrate surface, enhancing kinetic instability of water. Grain boundaries of polycrystalline hydrates are less stable compared to bulk phases and preferentially decompose, forming new dissociation fronts. This accelerates dissociation compared to monocrystalline hydrates. Fracture occurs at the grain boundaries of polycrystalline hydrate in the fluid, resulting in separate hydrate crystal grains. This fracture process further accelerates hydrate dissociation. In flow systems, methane nanobubbles form in fluid and readily transport with fluid flow. Unlike surface nanobubbles at static conditions, these liquid nanobubbles exhibit mobility. The findings of this study can contribute to a better understanding of the complex phase transition behavior of hydrate in confined environment, and provide theoretical support for improving production control technology.","Dissociation behaviors; Molecular simulation; Na-montmorillonite pore; Poly- and mono-crystalline hydrates; Static and dynamic fluid conditions","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-27","","","Engineering Thermodynamics","","",""
"uuid:803e316f-61ff-4ae7-9cf7-7cad5bb369aa","http://resolver.tudelft.nl/uuid:803e316f-61ff-4ae7-9cf7-7cad5bb369aa","Practical application of UVOX Redox® for pharmaceutical removal from liquid digestate in two biogas plants","Moradi, N. (TU Delft BT/Environmental Biotechnology; IHE Delft Institute for Water Education); Lopez Vazquez, C.M. (TU Delft BT/Environmental Biotechnology; IHE Delft Institute for Water Education); Hernandez, Hector Garcia (IHE Delft Institute for Water Education); Proskynitopoulou, Vera (Centre for Research and Technology-Hellas); Vouros, Anastasios (Centre for Research and Technology-Hellas); Garagounis, Ioannis (Centre for Research and Technology-Hellas); Lorentzou, Souzana (Centre for Research and Technology-Hellas); Brdjanovic, Damir (TU Delft BT/Environmental Biotechnology; IHE Delft Institute for Water Education); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)","","2024","In recent decades, there has been a growing focus on the management and valorization of digestate, primarily driven by its nutrient-rich composition, which positions it as a promising resource for biofertilizer production. However, several countries still restrict the direct application of digestate due to its potential environmental hazard, which includes the presence of contaminants of emerging concern (CECs) such as pharmaceuticals. This paper explores the efficacy of a novel UV/ozone-based technology, UVOX Redox®, in removing prevalent pharmaceuticals, including antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs), from the digestate of two biogas plants. In both cases, UVOX showed to be a feasible solution for pharmaceutical removal from digestate. Addition of hydrogen peroxide further increased the process efficiency, achieving > 90% removal of all compounds within an hour. The energy per order (EEO) value for all the studied pharmaceuticals was less than the reported median EEO for O3 and UV treatment, showcasing notable energy efficiency in UVOX technology. Moreover, the research highlights that the presence of ions augments the removal efficiency when applying the UVOX technology. In addition, the research results revealed a significant correlation between the effectiveness of the UVOX technology and UV transmittance, with R² exceeding 90% for pharmaceuticals and 75% for Dissolved Organic Carbon (DOC). This finding suggests that UV transmittance can serve as a viable surrogate method for implementing this advanced oxidation process in practical applications.","Liquid digestate; Pharmaceuticals; Surrogate method; UVOX Redox®","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:8cb705cf-916b-4e20-81a8-4adc2f289574","http://resolver.tudelft.nl/uuid:8cb705cf-916b-4e20-81a8-4adc2f289574","Analysis of improved digital filter inflow generation methods for compressible turbulent boundary layers","Laguarda, L. (TU Delft Aerodynamics); Hickel, S. (TU Delft Aerodynamics)","","2024","We propose several enhancements to improve the accuracy and performance of the digital filter turbulent inflow generation technique and assess their efficacy in the context of wall-resolved large-eddy simulations of a compressible turbulent boundary layer. Improvements of accuracy include a more realistic correlation function for the transversal directions, target length scales that vary with wall-distance, and a counter-intuitive approach that involves the suppression of streamwise velocity fluctuations at the inflow. For improving the computational performance, we propose to generate the inflow data in parallel in single precision and at a prescribed time interval based on the turbulence time scale, and not at every time-step of the simulation. Based on the results of 7 wall-resolved large-eddy simulations, we find that the new correlation functions and the considered performance improvements are beneficial and therefore desired. Suppressing streamwise velocity fluctuations at the inflow leads to the fastest relaxation of the pressure fluctuations; however, this approach increases the adaptation length defined in terms of compliance with the von Kármán integral equation. The adaptation length can be shortened by artificially increasing the wall-normal Reynolds stresses, thereby preserving the desired turbulence kinetic energy level. A detailed inspection of the Reynolds stress transport budgets reveals that the observed spurious spatial transients are largely driven by pressure-related terms. For instance, increased values of u′p′¯ are found throughout the computational domain when a physical Reynolds stress distribution is prescribed at the inflow. Therefore, efforts to enhance digital filter techniques should aim at modeling pressure fluctuations as well as their correlation with the velocity components.","Digital filter; Turbulence resolving simulation; Turbulent inflow generation","en","journal article","","","","","","","","","","","Aerodynamics","","",""
"uuid:1a4a7772-1a36-4e67-9f9f-9df501715e62","http://resolver.tudelft.nl/uuid:1a4a7772-1a36-4e67-9f9f-9df501715e62","Post-buckling behavior and collapse of Double-Double composite single stringer specimens","Vescovini, A. (TU Delft Aerospace Structures & Computational Mechanics; Politecnico di Milano); Li, Carina Xiaochen (University of Southern California); Paz Mendez, J. (TU Delft Aerospace Structures & Computational Mechanics; Universidad Rey Juan Carlos); Jin, Bo Cheng (University of Southern California); Manes, Andrea (Politecnico di Milano); Bisagni, C. (TU Delft Aerospace Structures & Computational Mechanics; Politecnico di Milano)","","2024","This paper presents the work on six single-stringer specimens manufactured using the card-sliding technique with non-crimp fabrics and adopting a Double-Double (DD) stacking sequence. These specimens, representative of sub-structure level components, are used to investigate post-buckling and failure in aerospace structures. Two specimens maintain a constant thickness cross-section, while four are tapered, two of which incorporate a Teflon insert in the stringer flange. All specimens are tested under compression loading conditions, inducing skin buckling, skin-stringer separation, and eventual collapse. Numerical simulations are validated by experimental results and serve to analyze the specimens behavior and the failure mode. The load versus displacement curves of both experimental tests and Finite Element Method (FEM) analyses are compared, along with the out-of-plane displacement field. Subsequently, the observed failure modes are discussed, focusing on the various mechanisms that occurred and considering the impact of flanges and stiffener tapering. Both the FEM simulations and experimental tests demonstrate good agreement, with the flanges tapering revealing notable results. This offers promising evidence of a viable solution to optimize aeronautical structures and enhance resistance to skin-stringer separation.","Double-Double (DD); Experimental tests; Finite element analysis; Post-buckling","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:a31094c4-6d91-4832-a6a5-394afe6ae3a4","http://resolver.tudelft.nl/uuid:a31094c4-6d91-4832-a6a5-394afe6ae3a4","Realizing quantum-safe information sharing: Implementation and adoption challenges and policy recommendations for quantum-safe transitions","Kong, I. (TU Delft Information and Communication Technology); Janssen, M.F.W.H.A. (TU Delft Engineering, Systems and Services); Bharosa, Nitesh (TU Delft Information and Communication Technology)","","2024","By utilizing the properties of quantum mechanics, quantum computers have the potential to factor a key pair of a large prime number and break some of the core cryptographic primitives that most information infrastructures depend on. This means that today's widely used cryptographic algorithms can soon become unsafe and need to be modified with quantum-safe (QS) cryptography. While much work is still needed in developing QS cryptographic algorithms, the institutional, organizational, and policy aspects of transitioning the current infrastructures have received less attention. This paper provides an empirical analysis of QS transition challenges and policy recommendations for moving to a QS situation. We analyzed the data collected through interviews with experts and practitioners from the Dutch government. The results reveal that institutional, organizational and policy aspects of QS transitions are interconnected, and solutions for QS transitions are scattered. Consequently, organizations may face a Catch-22 loop without further actionable approaches and planning for QS transitions.","Adoption; Digital government; Implementation; Information infrastructures; Information sharing; Policy recommendations; Post-quantum cryptography; Quantum-safe transition","en","journal article","","","","","","","","","","Engineering, Systems and Services","Information and Communication Technology","","",""
"uuid:f28cc468-2741-4e17-9c25-3117ee199407","http://resolver.tudelft.nl/uuid:f28cc468-2741-4e17-9c25-3117ee199407","Energy-conserving hyper-reduction and temporal localization for reduced order models of the incompressible Navier-Stokes equations","Klein, R.B. (TU Delft Fluid Mechanics; Centrum Wiskunde & Informatica (CWI)); Sanderse, B. (Centrum Wiskunde & Informatica (CWI))","","2024","A novel hyper-reduction method is proposed that conserves kinetic energy and momentum for reduced order models of the incompressible Navier-Stokes equations. The main advantage of conservation of kinetic energy is that it endows the hyper-reduced order model (hROM) with a nonlinear stability property. The new method poses the discrete empirical interpolation method (DEIM) as a minimization problem and subsequently imposes constraints to conserve kinetic energy. Two methods are proposed to improve the robustness of the new method against error accumulation: oversampling and Mahalanobis regularization. Mahalanobis regularization has the benefit of not requiring additional measurement points. Furthermore, a novel method is proposed to perform energy- and momentum-conserving temporal localization with the principle interval decomposition: new interface conditions are derived such that energy and momentum are conserved for a full time-integration instead of only during separate intervals. The performance of the new energy- and momentum-conserving hyper-reduction methods and the energy- and momentum-conserving temporal localization method is analysed using three convection-dominated test cases; a shear-layer roll-up, two-dimensional homogeneous isotropic turbulence and a time-periodic inviscid flow consisting of a vortex in a uniform background flow. Our main finding is that energy conservation in combination with oversampling or regularization leads to a robust method with excellent long time stability properties. When any of these two ingredients is missing, accuracy and/or stability is significantly impaired.","Discrete empirical interpolation method; Energy conservation; Incompressible Navier-Stokes equations; Mahalanobis regularization; Reduced order models; Temporal localization","en","journal article","","","","","","","","","","","Fluid Mechanics","","",""
"uuid:4c4e19f9-87a1-435d-81bd-9ab5e43bea05","http://resolver.tudelft.nl/uuid:4c4e19f9-87a1-435d-81bd-9ab5e43bea05","Impact of fast-solidification on all-d-metal NiCoMnTi based giant magnetocaloric Heusler compounds","Zhang, F. (TU Delft RST/Fundamental Aspects of Materials and Energy; City University of Hong Kong); Wu, Z. (TU Delft RST/Fundamental Aspects of Materials and Energy); Wang, Jianlin (Chinese Academy of Sciences); Wu, Zhenduo (City University of Hong Kong); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Eijt, S.W.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); Schut, H. (TU Delft RST/Neutron and Positron Methods in Materials); van Dijk, N.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); Brück, E.H. (TU Delft RST/Fundamental Aspects of Materials and Energy)","","2024","Recently, the all-d-metal Ni(Co)MnTi based Heusler compounds are found to have a giant magnetocaloric effect (GMCE) near room temperature and manifest different functionalities like multicaloric effects, which can be employed for solid-state refrigeration. However, in comparison to other traditional Heusler compounds, the relatively large thermal hysteresis (ΔThys) and moderately steep ferromagnetic phase transition provides limitations for real applications. Here, we present that fast solidification (suction casting) can sufficiently tailor the GMCE performance by modifying the microstructure. Compared with the arc-melted sample, the magnetic entropy change of the suction-casted sample shows a 67% improvement from 18.4 to 29.4 Jkg−1K−1 for a field change (∆μ0H) of 5 T. As the thermal hysteresis has maintained a low ΔThys value (5.5 K) for the enhanced first-order phase transition, a very competitive reversible magnetic entropy change of 21.8 Jkg−1K−1 for ∆μ0H = 5 T is obtained. Combining high-resolution transmission electron microscopy (HRTEM) and positron annihilation spectroscopy (PAS) results, the difference in lattice defect concentration is found to be responsible for the significant improvement in GMCE for the suction-cast sample, which suggests that defect engineering can be applied to control the GMCE. Our study reveals that fast solidification can effectively regulate the magnetocaloric properties of all-d-metal NiCoMnTi Heusler compounds without sacrificing ΔThys.","All-d-metal Heusler compounds; Lattice defects; Magnetocaloric effect; Ni-Co-Mn-Ti","en","journal article","","","","","","","","","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:9b12e05f-859d-4233-ae02-9fe762741a1e","http://resolver.tudelft.nl/uuid:9b12e05f-859d-4233-ae02-9fe762741a1e","Giant magnetocaloric effect for (Mn, Fe, V)2(P, Si) alloys with low hysteresis","Lai, J. (TU Delft Electrical Engineering, Mathematics and Computer Science; South China Normal University); Huang, B. (TU Delft RST/Fundamental Aspects of Materials and Energy); You, X. (TU Delft RST/Fundamental Aspects of Materials and Energy); Maschek, M. (TU Delft RST/Fundamental Aspects of Materials and Energy); Zhou, Guofu (South China Normal University); van Dijk, N.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); Brück, E.H. (TU Delft RST/Fundamental Aspects of Materials and Energy)","","2024","The Fe2P type Mn–Fe–P–Si alloys exhibit a giant magneto-elastic first-order transition, but the large hysteresis limits their performance. Crystal structure evolution and magnetocaloric performance were investigated by varying the Mn and Fe contents at a constant V substitution of 0.02 in Fe2P-type (Mn1.17-xFe0.73-yV0.02) (P0.5Si0.5) (where x + y = 0.02). The V substitution of Fe content shows a larger reduction of hysteresis compared with the same substitution amount of Mn content. During magnetoelastic phase transition, V-substitution reduces the volume change and the volumetric stresses, providing a superior mechanical stability. Compound with the V substitution of Fe (y = 0.02) shows the best magnetocaloric effect with a low thermal hysteresis of 0.6 K. Our developed Mn1.17-xFe0.73-yV0.02P0.5Si0.5 alloys are excellent materials for room-temperature magnetic heat-pumping applications by using a permanent magnet.","(Mn,Fe)(P,Si) alloy; Adiabatic temperature change; Crystal structure evolution; Hysteresis; Isothermal entropy change; Magnetocaloric effect","en","journal article","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:cbab1401-ba29-49e0-8427-951ee475176b","http://resolver.tudelft.nl/uuid:cbab1401-ba29-49e0-8427-951ee475176b","Synthetic Biology to Engineer Bacteriophage Genomes","Martins Costa, A.R. (TU Delft BN/Stan Brouns Lab); Azeredo, Joana (University of Minho); Pires, Diana Priscila (University of Minho)","Azeredo, Joana (editor); Sillankorva, Sanna (editor)","2024","Recent advances in the synthetic biology field have enabled the development of new molecular biology techniques used to build specialized bacteriophages with new functionalities. Bacteriophages have been engineered toward a wide range of applications, including pathogen control and detection, targeted drug delivery, or even assembly of new materials. In this chapter, two strategies that have been successfully used to genetically engineer bacteriophage genomes will be addressed: the bacteriophage recombineering of electroporated DNA (BRED) and the yeast-based phage-engineering platform.","Bacteriophage; Bacteriophage engineering; BRED; YAC","en","book chapter","Humana Press Inc.","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-26","","","BN/Stan Brouns Lab","","",""
"uuid:c994b2be-c0c9-4a3c-8a95-866bcc154288","http://resolver.tudelft.nl/uuid:c994b2be-c0c9-4a3c-8a95-866bcc154288","“Feel free to ask”: Nudging to promote asking questions in the online classroom","Weijers, Robert J. (Erasmus Universiteit Rotterdam); de Koning, Björn B. (Erasmus Universiteit Rotterdam); Scholten, Ester (Expertisecentrum Beroepsonderwijs); Wong, L.Y.J. (TU Delft Statistics); Paas, Fred (Erasmus Universiteit Rotterdam; University of Wollongong)","","2024","Asking questions is vital for learning, yet students seldom exhibit this behavior. Given the increasing presence of online classrooms in tertiary education, it is much needed to examine ways to encourage students to ask questions and increase their engagement. Despite the critical role of asking questions to enhance learning, little is known in research on promoting this behavior. Therefore, in this paper, we empirically tested the effect of nudging – a novel approach in education consisting of subtle interventions to change behavior – in online classrooms in tertiary education on question asking behavior, student engagement, and grades. In Experiment 1 (n = 1011), the teacher's virtual background prompted questions (prompt nudge), while in Experiment 2 (n = 449), the teacher set a goal for the students to ask one question per session (goal-setting nudge). We found a trend towards a positive effect of the prompt nudge on questions, but not on grades. Exploratory analyses revealed this was driven by students who already asked many questions. We found no effect of the goal-setting nudge on any measure, nor any effect in either experiment on student engagement. The findings demonstrate that the prompt nudge can be a possible useful and easy to implement tool to encourage questions in the online classroom.","Asking questions; Class participation; Educational psychology; Nudging; Online education; Student engagement","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-03","","","Statistics","","",""
"uuid:fde53f25-fdda-41ac-ac08-46419f2d9852","http://resolver.tudelft.nl/uuid:fde53f25-fdda-41ac-ac08-46419f2d9852","Enhanced magnetic halloysite nanotubes for dye removal at different pH conditions","Nguyen, Ngoc Quang (Chemistry and Research Institute for Convergence of Basic Science); Jeong, Younhee (Chemistry and Research Institute for Convergence of Basic Science); Abelmann, L. (TU Delft Bio-Electronics; KIST-Europe); Ryu, Jungju (Chemistry and Research Institute for Convergence of Basic Science); Sohn, Daewon (Chemistry and Research Institute for Convergence of Basic Science)","","2024","Halloysite nanotubes (HNTs) have been extensively investigated for potential utilization due to their unique structure and properties as a type of natural, eco-friendly clay. The synthesis and modification of magnetic halloysite nanotubes was studied using several experimental techniques including SEM, TEM, FT-IR, Raman spectroscopy, UV-Vis spectroscopy, and BET. Dye absorption experiments were conducted to understand bonding using EDS, XPS, XRD, and Raman spectroscopy. In this study, we evaluated Sunset Yellow FCF (SY) dye removal as a model to understand bonding structures among magnetic HNTs, magnetic particles, and dye molecules. We focus on the interactions of SY-magnetic HNTs and characteristics of magnetization by VSM after SY dye adsorption, which highlight the notable features of magnetic halloysite nanotubes. We used different pH environments to study the behavior of magnetic HNTs after dye absorption. The application of these modified HNTs is promising for future organic dye removal and wastewater treatment.","Dye adsorption; Dye removal; Halloysite; Magnetic particle; Nanotube","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-01","","","Bio-Electronics","","",""
"uuid:411c2dd6-9bcb-4aba-80ce-be761bb9f25a","http://resolver.tudelft.nl/uuid:411c2dd6-9bcb-4aba-80ce-be761bb9f25a","Assessment of Reynolds number effects in supersonic turbulent boundary layers","Laguarda, L. (TU Delft Aerodynamics); Hickel, S. (TU Delft Aerodynamics); Schrijer, F.F.J. (TU Delft Aerodynamics); van Oudheusden, B.W. (TU Delft Aerodynamics)","","2024","Wall-resolved large-eddy simulations (LES) are performed to investigate Reynolds number effects in supersonic turbulent boundary layers (TBLs) at Mach 2.0. The resulting database covers more than a decade of friction Reynolds number Reτ, from 242 to 5554, which considerably extends the parameter range of current high-fidelity numerical studies. Reynolds number trends are identified on a variety of statistics for skin-friction, velocity and thermodynamic variables. The efficacy of recent scaling laws as well as compressibility effects are also assessed. In particular, we observe the breakdown of Morkovin's hypothesis for third-order velocity statistics, in agreement with previous observations for variable-property flows at low Mach number. Special attention is also placed on the size and topology of the turbulent structures populating the TBL, with an emphasis on the outer-layer motions at high Reynolds number. The corresponding streamwise spectra of streamwise velocity fluctuations show a clear separation between inner and outer scales, where energetic peaks are found at streamwise wavelengths of λx+≈700 and λx/δ0≈6. The spanwise spacing of the outer-layer structures, in turn, is found to be insensitive to the Reynolds number and equal to ∼0.7δ0. It is also found that the integral length-scales in spanwise direction for the temperature, streamwise and spanwise velocity fields appear to progressively collapse with increasing Reynolds number. The modulating influence that the outer-layer structures exert on the near-wall turbulence is also clearly visible in many of the metrics discussed. In addition, the present LES data is further exploited to assess the Reτ-sensitivity of uniform momentum regions in the flow. We find that the resulting probability density function of the number of zones as well as its evolution with Reτ agrees well with incompressible data. This suggests that uniform zones, which have been associated with outer-layer dynamics, are not strongly influenced by compressibility at the considered Mach number.","Compressible wall-bounded turbulence; Large-eddy simulation; Supersonic boundary layer","en","journal article","","","","","","","","","","","Aerodynamics","","",""
"uuid:f70d2cbf-a0f9-4e92-afed-4b157c642b3c","http://resolver.tudelft.nl/uuid:f70d2cbf-a0f9-4e92-afed-4b157c642b3c","Distributed multi-target tracking and active perception with mobile camera networks","Casao, S. (Universidad de Zaragoza); Serra Gomez, A. (TU Delft Learning & Autonomous Control); Murillo, Ana C. (Universidad de Zaragoza); Böhmer, J.W. (TU Delft Algorithmics); Alonso-Mora, J. (TU Delft Learning & Autonomous Control); Montijano, Eduardo (Universidad de Zaragoza)","","2024","Smart cameras are an essential component in surveillance and monitoring applications, and they have been typically deployed in networks of fixed camera locations. The addition of mobile cameras, mounted on robots, can overcome some of the limitations of static networks such as blind spots or back-lightning, allowing the system to gather the best information at each time by active positioning. This work presents a hybrid camera system, with static and mobile cameras, where all the cameras collaborate to observe people moving freely in the environment and efficiently visualize certain attributes from each person. Our solution combines a multi-camera distributed tracking system, to localize with precision all the people, with a control scheme that moves the mobile cameras to the best viewpoints for a specific classification task. The main contribution of this paper is a novel framework that exploits the synergies that result from the cooperation of the tracking and the control modules, obtaining a system closer to the real-world application and capable of high-level scene understanding. The static camera network provides global awareness of the control scheme to move the robots. In exchange, the mobile cameras onboard the robots provide enhanced information about the people on the scene. We perform a thorough analysis of the people monitoring application performance under different conditions thanks to the use of a photo-realistic simulation environment. Our experiments demonstrate the benefits of collaborative mobile cameras with respect to static or individual camera setups.","Collaborative and autonomous decision making; Multi-camera scene analysis","en","journal article","","","","","","","","","","","Learning & Autonomous Control","","",""
"uuid:740ae19e-044a-4bb1-80c8-0c3da244b184","http://resolver.tudelft.nl/uuid:740ae19e-044a-4bb1-80c8-0c3da244b184","Dynamic risk assessment of chemical process systems using the System-Theoretic accident model and process approach (STAMP) in combination with cascading failure propagation model (CFPM)","Sun, Hao (Anhui University of Technology); Wang, Haiqing (China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science; Universiti Teknologi Malaysia); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven)","","2024","To maintain continuous production, chemical plant operators may ignore faults or handle faults online rather than shutting down process systems. However, interaction and interdependence links between components in a digitalized process system are substantial. Thus, faults will be propagated to downstream nodes, potentially leading to risk accumulation and major accidents. However, limited attention has been paid to this type of risk. To model the risk accumulation process, a dynamic risk assessment method is proposed by integrating the system-theoretic accident model and process approach (STAMP) and the cascading failure propagation model (CFPM). Firstly, STAMP is used to model and analyze the system safety of a process system. Two CFPMs are then proposed to measure risk accumulation under two different engineering situations. The proposed method is applied to the Chevron Richmond refinery crude unit and its associated upstream process. The results show that the proposed approach can effectively quantify the process of risk accumulation. This method can generate a real-time dynamic risk profile to support auxiliary decision-making.","Cascading failure propagation model (CFPM); Fault propagation; Risk accumulation; STAMP","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:690617c3-d24a-4212-81e5-39aab9dac733","http://resolver.tudelft.nl/uuid:690617c3-d24a-4212-81e5-39aab9dac733","Offshore floating PV–DC and AC yield analysis considering wave effects","Alcañiz Moya, A. (TU Delft Photovoltaic Materials and Devices); Monaco, N. (Student TU Delft); Isabella, O. (TU Delft Photovoltaic Materials and Devices); Ziar, H. (TU Delft Photovoltaic Materials and Devices)","","2024","The growing global energy demand increases the need for renewable energy sources. This increase requires land to be occupied, competing with other activities such as agriculture and residency. In such a situation, renewable energy sources expand to other environments like the ocean. However, this new scene poses some challenges, such as the effect of waves on photovoltaic (PV) performance. Consequently, this study aims to evaluate the power output of an Offshore Floating PV (OFPV) system located in the North Sea considering the effect of the waves. A 3D mechanical movement model, which has been validated with data from a real system, is developed for this purpose. A sensitivity analysis is conducted to determine how the size of fluctuations depends on the dimensions of the floater. The main outcome is that a heavy and wide floater aligned with the most common wind direction reduces angle variations. Results from DC power simulations show that sea fluctuations have a negative yet small influence on PV power production. Over the course of the year, these losses amount to just 0.1% of the annual energy yield. However, a hypothetical optimally-tilted PV system placed on water would still generate 14.6% more DC power output than the floating one. On the AC side, laboratory experiments show that these oscillations negatively affect the inverter efficiency during rough sea conditions by a decrease of over 2 percentage points compared to a still system.","Floating photovoltaics; Inverter efficiency; Offshore; Waves effect; Yield assessment","en","journal article","","","","","","","","","","","Photovoltaic Materials and Devices","","",""
"uuid:ffd10390-e207-4109-8745-f86224e7abff","http://resolver.tudelft.nl/uuid:ffd10390-e207-4109-8745-f86224e7abff","Design of the new structure and capabilities of LADM edition II including 3D aspects","Kara, A. (TU Delft Digital Technologies); Lemmen, Christiaan (University of Twente); van Oosterom, P.J.M. (TU Delft Digital Technologies); Kalogianni, E. (TU Delft Digital Technologies); Alattas, Abdullah (King Abdulaziz University); Indrajit, Agung (Ministry of National Development Planning/National Development Agency of the Republic of Indonesia)","","2024","The decision to refine the existing content and to extend the scope of Edition I of the ISO 19152:2012 Land Administration Domain Model (LADM) is a response to requests from the international Land Administration (LA) community. This response has to be formally organised in accordance with ISO guidelines. This begins with gathering feedback from ISO/TC 211 Member States on the need for updated and enhanced capabilities of the LADM. In addition, several proposals have been made to extend the scope of the LADM Edition I. After analysing the feedback received, it was proposed to develop the LADM Edition II as a multi-part standard: Part 1 — Generic conceptual model, Part 2 — Land registration, Part 3 — Marine georegulation, Part 4 — Valuation information, Part 5 — Spatial plan information and Part 6 — Implementation aspects. In other words, Edition I focuses on land tenure, while the design and development of Edition II is based on the inclusion of rights, restrictions and responsibilities (RRRs) concerning marine georegulation, valuation information, spatial plan information as well as LADM implementation. 3D representations are relevant for all parts.
This paper focuses on the design of the new structure of the second edition of the LADM and on the (operational) capabilities of this new edition in relation to the LA issues in Parts (standards addressing a specific part of the scope) and Packages (groups of conceptually close classes), with a particular attention to the requirements and design related decisions taken in the revision process. The parts 1, 2, 4 and 5 are the parts in which the authors are currently involved. Part 1 will be a high-level umbrella standard; Part 2 is largely based on LADM Edition I and focuses on land registration, with an enhanced support on the surveying functionality, including new subclasses of spatial unit, and extended 3D spatial profiles. Part 3 harmonises the description of RRRs and aligns land concepts with marine aspects from the marine domain based on the International Hydrographic Organisation (IHO) S121 Maritime Limits and Boundaries Product Specification. Part 4 deals with valuation information used and produced in the context of land administration, while Part 5 deals with spatial planning information and includes the planned use of the land (zoning), resulting in RRRs. Lastly, Part 6 is planned to be about implementation of the LADM and will be developed in close collaboration with the Open Geospatial Consortium (OGC).","3D representation; Cadastre; LADM; LADM edition II; LADM revision; Land administration; Land administration domain model; Land registry; Social tenure domain model; Standards; STDM","en","journal article","","","","","","","","","","","Digital Technologies","","",""
"uuid:25fd50b0-20cd-4f2d-b225-e657851b68b8","http://resolver.tudelft.nl/uuid:25fd50b0-20cd-4f2d-b225-e657851b68b8","Biocompatible optical physically unclonable function hydrogel microparticles for on-dose authentication","Zhang, M. (TU Delft Engineering Thermodynamics); Raghunath, Aparna; Zhao, A. (TU Delft Energy Technology); Eral, H.B. (TU Delft Complex Fluid Processing; Universiteit Utrecht)","","2024","On-dose authentication (ODA) enhances security by incorporating customized molecular or micro-tags into each pill, preventing counterfeit products in genuine packages. ODA's security relies on tag non-replication and non-reverse engineering. Combining ODA with graphical Physical Unclonable Functions (PUF) promises maximum security. PUF uses intrinsic micro or nanoscale randomness as a unique ‘fingerprint’. However, current graphical PUFs have limitations like specific illumination requirements and the use of toxic materials, restricting their use in pharmaceuticals. In this study, we propose a novel approach called on-dose PUF. This method involves embedding microspheres randomly within micro biocompatible hydrogel particles. We showcase two distinct types of such on-dose PUFs. The first type utilizes randomly distributed superparamagnetic colloids (SPC) of identical diameters, while the second type utilizes vortexed sunflower oil drops of various diameters. The diameter and coordinates of the microspheres serve as input for generating cryptographic keys. A universal circle identification and binning program is used for extracting this information. One advantage of this approach is that it enables imaging using white light illumination and low-magnification microscopy, as color and signal intensity information are not crucial. This method enables patients to verify their medication by using their mobile phones from home. To assess the performance of the proposed on-dose PUF, we conducted canonical investigations on the single-diameter system. This system can only generate one layer of cryptographic keys, making it potentially more vulnerable than the multiple-diameter system. However, the single-diameter system successfully passed NIST Statistical tests and exhibited sufficient randomness, ideal bit uniformity, Hamming distance, and device uniqueness. Furthermore, we found that the encoding capacity of the single-diameter system was 9.2×1018, providing ample labeling potential.","Anti-counterfeiting; Biocompatible; Colloid; Emulsion; Hydrogel; On-dose authentication; Optical PUF; Physical unclonable function","en","journal article","","","","","","","","","","","Engineering Thermodynamics","","",""
"uuid:f86b4e03-54f0-46d0-94e8-a1cf834df8f8","http://resolver.tudelft.nl/uuid:f86b4e03-54f0-46d0-94e8-a1cf834df8f8","An integrated approach to decision-making variables on urban water systems using an urban water use (UWU) decision-support tool","Hoepers, Taiane Regina (Federal University of Paraná; IHE Delft Institute for Water Education); Leithold, Juliana (Federal University of Paraná); Monteiro, Michel Marques (Federal University of Paraná); Corzo Perez, Gerald A. (IHE Delft Institute for Water Education); Fernandes, Cristovão V. Scapulatempo (Federal University of Paraná); Zevenbergen, C. (TU Delft Urban Design; IHE Delft Institute for Water Education); Santos, Daniel Costa dos (Federal University of Paraná)","","2024","In response to pressing global challenges like climate change, rapid population growth, and an urgent need for sustainable infrastructure, cities face an immediate and crucial necessity to transition swiftly toward an integrated approach to managing urban water resources. This shift is not merely an option but an imperative, driven by the rapidly evolving urban landscape. In addressing this imperative, a crucial decision support tool that has emerged as an asset in the domain of urban water planning and management is the Urban Water Use (UWU) tool. This tool offers an integrated approach for strategic planning, promoting urban water conservation and environmental health through the investigation of interventions in urban infrastructure under different scenarios. In this study, the latest version of this UWU tool was deployed in a case study conducted in Almirante Tamandaré, Brazil. The objective was to evaluate how an integrated decision-making approach concerning urban water systems influences the efficiency and effectiveness of interventions, ultimately contributing to achieve widespread adoption, accessibility, and relevance of urban water services. The refined UWU tool evaluates a spectrum of measures across diverse scenarios, incorporating various drivers, focusing on the stakeholders' visions for the locality. These visions are composed of sustainability indicators, specifying different sets of target values and importance weights for each indicator. The approach followed in this study demonstrates how the effectiveness indexes can vary based on stakeholders' perception. Measures under Water Sensitive Urban Design and Water Demand Management strategies were deployed to simulate the response of urban water systems under three distinct scenarios, embracing the complexities of social dynamics and of climate change. The findings of the study emphasize that realizing a desired vision through selected measures relies significantly on the adoption of an integrated approach within the decision-making process. The stakeholders' perception of how indicators should be weighted while defining the vision was found to significantly impact the effectiveness range of these measures.","Effectiveness index; Indicators; Integrated urban water management; Measures; Scenarios","en","journal article","","","","","","","","","","","Urban Design","","",""
"uuid:07f833c3-820b-4b91-b0bd-6db3491856cb","http://resolver.tudelft.nl/uuid:07f833c3-820b-4b91-b0bd-6db3491856cb","Unveiling the catalytic potential of two-dimensional boron nitride in lithium–sulfur batteries","Khossossi, N. (TU Delft Team Poulumi Dey); Singh, Deobrat (Uppsala University); Essaoudi, Ismail (Moulay Ismail University); Ahuja, Rajeev (Uppsala University; Indian Institute of Technology Ropar); Ainane, Abdelmajid (Moulay Ismail University)","","2024","Lithium–sulfur (Li–S) batteries, renowned for their potential high energy density, have attracted attention due to their use of earth-abundant elements. However, a significant challenge lies in developing suitable materials for both lithium-based anodes, which are less prone to lithium dendrite formation, and sulfur-based cathodes. This obstacle has hindered their widespread commercial viability. In this study, we present a novel sulfur host material in the form of a two-dimensional semiconductor boron nitride framework, specifically the 2D orthorhombic diboron dinitride (o-B2N2). The inherent conductivity of o-B2N2 mitigates the insulating nature often observed in sulfur-based electrodes. Notably, the o-B2N2 surface demonstrates a high binding affinity for long-chain Li-polysulfides, leading to a significant reduction in their dissolution into the DME/DOL electrolytes. Furthermore, the preferential deposition of Li2S on the o-B2N2 surface expedites the kinetics of the lithium polysulfide redox reactions. Additionally, our investigations have revealed a catalytic mechanism on the o-B2N2 surface, significantly reducing the free energy barriers for various sulfur reduction reactions. Consequently, the integration of o-B2N2 as a host cathode material for Li–S batteries holds great promise in suppressing the shuttle effect of lithium polysulfides and ultimately enhancing the overall battery performance. This represents a practical advancement for the application of Li–S batteries.","2D o-BN monolayer; Electrocatalytic properties; First-principles calculations; Lithium polysulfide; Organic electrolyte; Shuttle effect","en","journal article","","","","","","","","","","","Team Poulumi Dey","","",""
"uuid:dd6a5c46-601d-4625-8b90-55ee9ee12330","http://resolver.tudelft.nl/uuid:dd6a5c46-601d-4625-8b90-55ee9ee12330","Enhancing pseudocapacitive intercalation in Ti3C2T x MXene with molecular crowding electrolytes","Chen, C. (TU Delft RST/Storage of Electrochemical Energy); de Kogel, Albert (Student TU Delft); Weijers, M.J. (TU Delft ChemE/Materials for Energy Conversion and Storage); Bannenberg, L.J. (TU Delft RID/TS/Instrumenten groep); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy)","","2024","The growing demand for safe, cost-efficient, high-energy and high-power electrochemical energy storage devices has stimulated the development of aqueous-based supercapacitors with high capacitance, high rate capability, and high voltage. 2D titanium carbide MXene-based electrodes have shown excellent rate capability in various dilute aqueous electrolytes, yet their potential window is usually narrower than 1.2 V. In this study, we show that the potential window of Ti3C2T x MXene can be efficiently widened to 1.5 V in a cost-effective and environmentally benign polyethylene glycol (PEG) containing molecular crowding electrolyte. Additionally, a pair of redox peaks at −0.25 V/−0.05 V vs. Ag (cathodic/anodic) emerged in cyclic voltammetry after the addition of PEG, yielding an additional 25% capacitance. Interestingly, we observed the co-insertion of the molecular crowding agent PEG-400 during the Li+ intercalation process based on in-situ x-ray diffraction analysis. As a result, Ti3C2T x electrodes presented an interlayer space change of 4.7 Å during a complete charge/discharge cycle, which is the largest reversible interlayer space change reported so far for MXene-based electrodes. This work demonstrates the potential of adding molecular crowding agents to improve the performance of MXene electrodes in aqueous electrolytes and to enlarge the change of the interlayer spacing.","electrochemical energy storage; intercalation; interlayer spacing; molecular crowding electrolyte; MXene; polyethylene glycol; supercapacitor","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:5d612ad9-dcd2-43cb-a9d6-61997eed923d","http://resolver.tudelft.nl/uuid:5d612ad9-dcd2-43cb-a9d6-61997eed923d","A comparison of smooth basis constructions for isogeometric analysis","Verhelst, H.M. (TU Delft Numerical Analysis; TU Delft Ship and Offshore Structures); Weinmüller, P. (MTU Aero Engines); Mantzaflaris, A. (INRIA Sophia Antipolis); Takacs, T. (Johann Radon Institute for Computational and Applied Mathematics); Toshniwal, D. (TU Delft Numerical Analysis)","","2024","In order to perform isogeometric analysis with increased smoothness on complex domains, trimming, variational coupling or unstructured spline methods can be used. The latter two classes of methods require a multi-patch segmentation of the domain, and provide continuous bases along patch interfaces. In the context of shell modelling, variational methods are widely used, whereas the application of unstructured spline methods on shell problems is rather scarce. In this paper, we therefore provide a qualitative and a quantitative comparison of a selection of unstructured spline constructions, in particular the D-Patch, Almost-C1, Analysis-Suitable G1 and the Approximate C1 constructions. Using this comparison, we aim to provide insight into the selection of methods for practical problems, as well as directions for future research. In the qualitative comparison, the properties of each method are evaluated and compared. In the quantitative comparison, a selection of numerical examples is used to highlight different advantages and disadvantages of each method. In the latter, comparison with weak coupling methods such as Nitsche's method or penalty methods is made as well. In brief, it is concluded that the Approximate C1 and Analysis-Suitable G1 converge optimally in the analysis of a bi-harmonic problem, without the need of special refinement procedures. Furthermore, these methods provide accurate stress fields. On the other hand, the Almost-C1 and D-Patch provide relatively easy construction on complex geometries. The Almost-C1 method does not have limitations on the valence of boundary vertices, unlike the D-Patch, but is only applicable to biquadratic local bases. Following from these conclusions, future research directions are proposed, for example towards making the Approximate C1 and Analysis-Suitable G1 applicable to more complex geometries.","Biharmonic equation; Isogeometric analysis; Kirchhoff–Love shell; Unstructured splines","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:edf67d8a-fc91-46c7-a195-809612dc5339","http://resolver.tudelft.nl/uuid:edf67d8a-fc91-46c7-a195-809612dc5339","Lengthening of the Sm2+ 4f55d → 4f6 decay time through interplay with the 4f6[5D0] level and its analogy to Eu2+ and Pr3+","van Aarle, C. (TU Delft RST/Luminescence Materials); Krämer, Karl W. (University of Bern); Dorenbos, P. (TU Delft RST/Luminescence Materials)","","2024","Recent research activity on Sm2+-doped compounds has significantly increased the amount of available data on 4f55d → 4f6 decay times. This enabled the systematic comparison of spectroscopic and time resolved luminescence data to theoretical models describing the interplay between the 4f55d and 4f6[5D0] excited states on the observed decay time. A Boltzmann distribution between the population of the excited states is assumed, introducing a dependence of the observed 4f55d → 4f6 decay time on the energy gap between the 4f55d and 4f6[5D0] levels and temperature. The model is used to interpret the origin of the large variation in reported 4f55d → 4f6 decay times through literature, and links their temperature dependence to applications such as luminescence thermometry and near-infrared scintillation. The model is further applied to the analogous situation of close lying 4fn-15d and 4fn states in Eu2+ (6P7/2) and Pr3+ (1S0).","","en","journal article","","","","","","","","","","","RST/Luminescence Materials","","",""
"uuid:89773979-ec28-4e36-89d8-399e1404f039","http://resolver.tudelft.nl/uuid:89773979-ec28-4e36-89d8-399e1404f039","Enhancing nitrogen removal from wastewater in a low C/N ratio using an air-lift bio-electrochemical reactor (ALBER)","Nouri, Amir (Razi University); Zinatizadeh, Ali Akbar (Razi University; University of Queensland); Zinadini, Sirus (Razi University); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)","","2024","This study focuses on the development of an air-lift bio-electrochemical reactor (ALBER) with a continuous feeding regime. The objective is to enhance nitrogen removal from synthetic wastewater with a low carbon-to-nitrogen (C/N) ratio. The chemical oxygen demand (COD) and total nitrogen (TN) of the influent wastewater were 500 and 200 mg/L, respectively. The effect of four independent variables, i.e., temperature, hydraulic retention time (HRT), N−NH4+/TN ratio and current density in the range of 16–32 °C, 6–12 h, 25–75%, and 2–10 A/m2, respectively, at three levels on the bio–electrochemical reactor performance were investigated during the bio–electrochemical reactor operation. The Face Center Cube (FCC) of response surface methodology (RSM) was used for design of experiments and model of obtained data. The ALBER achieved the maximum TN removal of 73% (146 mg/l) using external voltage and zeolite/plastic medium at temperature of 16 °C, HRT of 6 h, current density of 2 A/m2 and N−NH4+/TN ratio of 75%. The results indicated that shortening the HRT from 12 to 6 h, reducing the temperature from 32 °C to 24 °C, increasing the current density from 2 to 6 A/m2 and the reduction of nitrate concentration caused an increase in the TN removal. The results indicated that the performance of air-lift bio-electrochemical for nitrogen removal could be attributed to autotrophic denitrification (AD) and simultaneous nitrification/denitrification (SND). The research findings suggest that the ALBER should be further studied for potential use in treating industrial wastewater at low temperatures.","Air-lift bio-electrochemical reactor; Autotrophic denitrification; Biocathode; Simultaneous nitrification/denitrification; Zeolite/plastic medium","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-15","","","BT/Environmental Biotechnology","","",""
"uuid:876ab669-df05-486c-b6e4-416efae3d114","http://resolver.tudelft.nl/uuid:876ab669-df05-486c-b6e4-416efae3d114","Fault detection for LTI systems using data-driven dissipativity analysis","Rosa, Tábitha E. (Rijksuniversiteit Groningen); de Paula Carvalho, Leonardo (Universidade de São Paulo); de Albuquerque Gleizer, G. (TU Delft Team Tamas Keviczky); Jayawardhana, Bayu (Rijksuniversiteit Groningen)","","2024","Motivated by the physical exchange of energy and its dissipation in electro-mechanical systems, we propose a new fault detection method based on data-driven dissipativity analysis. We first identify a dissipativity inequality using one or multiple shots of data obtained from a linear time-invariant system. This dissipativity inequality's storage and supply rate functions assume generic quadratic difference forms encompassing all LTI systems. By analysing the norm of the identified dissipative inequality as the residual function, we can detect the occurrence of faults in real-time without the need to model each fault the system is subjected to. Through academic examples, we demonstrate how we can identify supply rate and storage functions from persistently exciting data shots. We present a practical example of detecting faults on a two-degree-of-freedom planar manipulator with zero missed fault detection rate, which is compared to a standard PCA-based fault detection algorithm.","Data-driven; Dissipativity; Fault detection; LTI systems; Model-free","en","journal article","","","","","","","","","","","Team Tamas Keviczky","","",""
"uuid:ebe708b5-dd7f-465e-9a26-7aa460a4957c","http://resolver.tudelft.nl/uuid:ebe708b5-dd7f-465e-9a26-7aa460a4957c","Compensating torque ripples in a coarse pointing mechanism for free-space optical communication: A Gaussian process repetitive control approach","Mooren, Noud (Eindhoven University of Technology); van Meer, Max (Eindhoven University of Technology); Witvoet, Gert (Eindhoven University of Technology; TNO); Oomen, T.A.E. (TU Delft Team Jan-Willem van Wingerden; Eindhoven University of Technology)","","2024","Actuators that require commutation algorithms, such as the switched reluctance motor (SRM) considered in this paper and employed in the coarse pointing assembly (CPA) for free-space optical communication, often have torque-ripple disturbances that are periodic in the commutation-angle domain that deteriorate the positioning performance. The aim of this paper is to model the torque ripple as a Gaussian Process (GP) in the commutation-angle domain and consequently compensate for it at arbitrary velocity. The approach employs repetitive control (RC) at a constant velocity. A spatial GP with a periodic kernel is trained using data that is obtained from the RC step resulting in a static non-linear function for compensation at arbitrary velocity. Stability conditions are provided for both steps. The approach is successfully applied to a CPA prototype to improve the tracking performance for laser communication, where the torque ripple is compensated at arbitrary velocity.","Gaussian process; Motion control; Optical pointing; Repetitive control; Switched reluctance motor","en","journal article","","","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:16169a19-bf6b-4681-8ecc-18a9f2bd5e0f","http://resolver.tudelft.nl/uuid:16169a19-bf6b-4681-8ecc-18a9f2bd5e0f","End-to-end neural network based optimal quadcopter control","Ferede, R. (TU Delft Control & Simulation); de Croon, G.C.H.E. (TU Delft Control & Simulation); de Wagter, C. (TU Delft Control & Simulation); Izzo, Dario (European Space Agency (ESA))","","2024","Developing optimal controllers for aggressive high-speed quadcopter flight poses significant challenges in robotics. Recent trends in the field involve utilizing neural network controllers trained through supervised or reinforcement learning. However, the sim-to-real transfer introduces a reality gap, requiring the use of robust inner loop controllers during real flights, which limits the network's control authority and flight performance. In this paper, we investigate for the first time, an end-to-end neural network controller, addressing the reality gap issue without being restricted by an inner-loop controller. The networks, referred to as G&CNets, are trained to learn an energy-optimal policy mapping the quadcopter's state to rpm commands using an optimal trajectory dataset. In hover-to-hover flights, we identified the unmodeled moments as a significant contributor to the reality gap. To mitigate this, we propose an adaptive control strategy that works by learning from optimal trajectories of a system affected by constant external pitch, roll and yaw moments. In real test flights, this model mismatch is estimated onboard and fed to the network to obtain the optimal rpm command. We demonstrate the effectiveness of our method by performing energy-optimal hover-to-hover flights with and without moment feedback. Finally, we compare the adaptive controller to a state-of-the-art differential-flatness-based controller in a consecutive waypoint flight and demonstrate the advantages of our method in terms of energy optimality and robustness.","End-to-end control; G&CNet; Optimal control; Reality gap; Sim-to-real transfer; Supervised learning","en","journal article","","","","","","","","","","","Control & Simulation","","",""
"uuid:b551f1a3-ce70-4680-a69c-c9f19ab32361","http://resolver.tudelft.nl/uuid:b551f1a3-ce70-4680-a69c-c9f19ab32361","An advanced inverse modeling framework for efficient and flexible adjoint-based history matching of geothermal fields","Tian, X. (TU Delft Reservoir Engineering; Chinese Academy of Sciences); Volkov, Oleg (Stanford University); Voskov, D.V. (TU Delft Reservoir Engineering; Stanford University)","","2024","In this study, we present an efficient and flexible adjoint-based framework for history matching and forecasting geothermal energy extraction at a large scale. In this framework, we applied the Principal Component Analysis to reduce the parameter space for representing the complex geological model. The adjoint method is implemented for gradient calculation to speed up the history-matching iteration process. Operator-based linearization (OBL) used in this framework makes the calculation of the physical state and its derivatives very efficient and facilitates the matrix assembly in the adjoint method. This study primarily focuses on history matching based on combined observation of well production and in-situ electromagnetic measurements to predict the temperature front. However, different types of misfit terms can be added to the objective function based on practical considerations. For example, our history-matching case studies include model misfit terms applied for regularization purposes. The measurement data is extracted from the true model, and realistic measurement errors are considered. Also, in this work, we propose an optimal weighting strategy for the terms of the objective function to balance their sensitivity with respect to the model control variables. The high efficiency of the framework is demonstrated for the geothermal doublet model implemented at the heterogeneous reservoir with multiple realizations. The framework allows for generating posterior Randomized Maximum Likelihood (RML) estimates of the entire ensemble of the realizations with a reasonable computational cost. Results show that the framework can achieve reliable history-matching results based on the doublets production data and the reservoir electromagnetic measurement.","Adjoint method; DARTS; Geothermal energy; History matching; Principal Component Analysis","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:aa9977c0-85d9-451b-9b1c-0337c67d9236","http://resolver.tudelft.nl/uuid:aa9977c0-85d9-451b-9b1c-0337c67d9236","Frankenstein: fast and lightweight call graph generation for software builds","Keshani, M. (TU Delft Software Engineering); Gousios, G. (TU Delft Software Technology; Endor Labs); Proksch, S. (TU Delft Software Engineering)","","2024","Call Graphs are a rich data source and form the foundation for advanced static analyses that can, for example, detect security vulnerabilities or dead code. This information is invaluable when it is immediately available, such as in the output of a build system. Call Graph generation is a whole-program analysis: not just the application, but also all its dependencies are processed together. Recent work has shown that even advanced static analyses can use summarization techniques to substantially improve runtime; however, existing analyses focus on soundness, and as such remain very expensive. When executed in the build system, which typically has limited resources, even powerful servers suffer from slow build times, rendering these analyses impractical in today’s fast-paced development. In this paper, we aim to strike a balance between improving static analyses while remaining practical for use cases that require quick results in low-resource environments. We propose a summarization-based implementation of a Class-Hierarchy Analysis algorithm for call graph generation of Java programs. Our approach leverages the fact that dependency sets often do not change between builds: we can generate call graphs for these dependencies, cache their generation for subsequent builds, and using a novel stitching algorithm, Frankenstein, merge all partial results into a complete call graph for the whole program. Our evaluation results show that this lightweight approach can substantially outperform existing frameworks. In terms of speed improvements, Frankenstein surpasses the baselines by up to 38%, requiring an average of just 388 Megabytes of memory. This makes the proposed approach practical for build systems with limited memory resources. Despite these optimizations, our generated call graphs maintain a near-identical set of edges when compared to the baselines, achieving an F 1 score of up to 0.98. This summarization-based approach for call graph generation paves the way for using extended static analyses in build processes.","Build systems; Call graph generation; Software ecosystems; Software engineering in practice","en","journal article","","","","","","","","","","Software Technology","Software Engineering","","",""
"uuid:fa5c7391-b1d5-40c6-b78c-10e95d80c2f4","http://resolver.tudelft.nl/uuid:fa5c7391-b1d5-40c6-b78c-10e95d80c2f4","One setup for many experiments: enabling versatile student-led investigations","Pols, C.F.J. (TU Delft ImPhys/Docenten; TU Delft Science Education and Communication)","","2024","This article presents an experimental setup capable of conducting various experiments. The setup is used to accurately determine the acceleration due to gravity using either the pendulum or free fall experiment, as well as to allow students to conceive and conduct their own experiment. We discuss the design of the setup and the experiments conducted with it, highlighting the versatility and potential use for open inquiry. We include students’ perception on this particular experiment and how it led to an interesting and educational open inquiry.","acceleration of gravity; free fall; introductory lab course; lab course; open inquiry; pendulum; practical work","en","journal article","","","","","","","","","","","ImPhys/Docenten","","",""
"uuid:efbe4f90-036f-4c3d-a2aa-6fadd06e804a","http://resolver.tudelft.nl/uuid:efbe4f90-036f-4c3d-a2aa-6fadd06e804a","Low- and high-temperature heat capacity of metallic technetium","Zappey, J.N. (TU Delft RST/Reactor Physics and Nuclear Materials; European Commission Joint Research Centre); Moore, E. E. (European Commission Joint Research Centre; Lawrence Livermore National Laboratory); Beneš, O. (European Commission Joint Research Centre); Griveau, J. C. (European Commission Joint Research Centre); Konings, R. (TU Delft EMSD AS-south Project technicians; European Commission Joint Research Centre)","","2024","The heat capacity of technetium metal has been measured from 2.1 K to 293 K using relaxation calorimetry and the enthalpy increment up to 1700 K using drop calorimetry. The low-temperature calorimetry measurements revealed a superconducting transition temperature of TC = (7.76 ± 0.08) K. The zero-degree Debye temperature(θE) and the electronic heat capacity coefficient (γe) of the normal state were derived as (307 ± 5) K and (4.22 ± 0.20) mJ·K−2·mol−1, respectively. The standard entropy of the superconducting standard state was derived as Sm° (298.15) = (36.8 ± 1.3) J·K−1·mol−1. The fitting of enthalpy-increment data together with high-temperature heat capacity data reported in literature yielded a heat capacity equation up to 1700 K.","Calorimetry; Enthalpy; Fission product; Heat capacity; Technetium","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-30","","","RST/Reactor Physics and Nuclear Materials","","",""
"uuid:72cb8cc8-1229-4c81-b388-173cd57c5741","http://resolver.tudelft.nl/uuid:72cb8cc8-1229-4c81-b388-173cd57c5741","Tuning stability of titania-supported Fischer-Tropsch catalysts: Impact of surface area and noble metal promotion","van Koppen, L.M. (TU Delft RST/Fundamental Aspects of Materials and Energy; Eindhoven University of Technology); Dugulan, A.I. (TU Delft RST/Fundamental Aspects of Materials and Energy; TU Delft RID/TS/Instrumenten groep); Hensen, Emiel J.M. (Eindhoven University of Technology); Bezemer, G. Leendert (Shell Global Solutions International B.V.)","","2024","Cobalt oxidation is a relevant deactivation pathway of titania-supported cobalt catalysts used in Fischer-Tropsch synthesis (FTS). To work towards more stable catalysts, we studied the effect of the surface area of the titania support and noble metal promotion on cobalt oxidation under simulated high conversion conditions. Mössbauer spectroscopy was used to follow the evolution of cobalt during reduction and FTS operation as a function of the steam pressure. The reduction of the oxidic cobalt precursor becomes more difficult due to stronger metal-support interactions when the titania surface area is increased. The reducibility was so low for cobalt on GP350 titania (surface area 283 m2/g) that the catalytical activity was negligible. Although cobalt was more difficult to reduce on P90 titania (94 m2/g) than on commonly used P25 titania (50 m2/g), the Co/P90 catalyst showed increased resistance against cobalt sintering and higher FTS performance than Co/P25. The addition of platinum to Co/P90 led to a higher reduction degree of cobalt and a higher cobalt dispersion, representing a catalyst with promising performance at relatively low steam pressure. Nevertheless, the stronger cobalt-titania interactions result in more extensive deactivation at high steam pressure due to oxidation.","Cobalt; Deactivation; Fischer-Tropsch synthesis; Mössbauer spectroscopy, SMSI; Oxidation","en","journal article","","","","","","","","","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:6141e039-caf8-4825-ac12-107450c64c9e","http://resolver.tudelft.nl/uuid:6141e039-caf8-4825-ac12-107450c64c9e","Ultrafiltration (UF) and biological oxygen-dosed activated carbon (BODAC) filtration to prevent fouling of reversed osmosis (RO) membranes: A mass balance analysis","Ribeiro Pinela, Sara (Wetsus, Centre for Sustainable Water Technology; Wageningen University & Research); Larasati, Amanda (Wetsus, Centre for Sustainable Water Technology); Meulepas, Roel J.W. (Wetsus, Centre for Sustainable Water Technology); Gagliano, Maria Cristina (Wetsus, Centre for Sustainable Water Technology); Kleerebezem, R. (TU Delft BT/Environmental Biotechnology); Bruning, Harry (Wageningen University & Research); Rijnaarts, Huub H.M. (Wageningen University & Research)","","2024","(Bio)fouling is the most common problem in membrane processes used in water production. It is also a reported unavoidable problem, with mitigation strategies being frequently ineffective in addressing this problem. An ultrapure water plant (UPW) in Emmen (The Netherlands), fed with secondary effluent, comprises the following subsequent treatment steps: ultrafiltration (UF), biological oxygen-dosed activated carbon (BODAC) filtration and reverse osmosis (RO). The BODAC filters were designed to prevent fouling in RO membranes, and for ten years, they have been operated without significant fouling issues. The present work aims to provide insight into the role of the full-scale UF + BODAC in fouling prevention, by conducting a mass balance (MB) analysis to assess the removal/release of common fouling precursors. Positive MB results were noticed for particulate organic compounds, iron (Fe) and manganese (Mn) meaning their constant removal in the UF + BODAC. The UF + BODAC was shown to be an effective nitrification system, effectively converting all the ammonium and nitrite to nitrate. In conclusion, the combined removal of organics, Fe, and Mn species and nitrification by UF + BODAC is most likely an important factor in downstream fouling prevention, making this system an attractive process for fouling prevention. Nevertheless, further investigations to discover the mechanisms involved are needed.","Biological oxygen-dosed activated carbon; Fouling precursors; Fouling prevention; Mass balance; Ultrafiltration","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:8ebfa298-5734-45f5-b5d0-60d9f45b7352","http://resolver.tudelft.nl/uuid:8ebfa298-5734-45f5-b5d0-60d9f45b7352","Monte Carlo convergence rates for kth moments in Banach spaces","Kirchner, K. (TU Delft Analysis); Schwab, Christoph (ETH Zürich)","","2024","We formulate standard and multilevel Monte Carlo methods for the kth moment Mεk[ξ] of a Banach space valued random variable ξ:Ω→E, interpreted as an element of the k-fold injective tensor product space ⊗εkE. For the standard Monte Carlo estimator of Mεk[ξ], we prove the k-independent convergence rate [Formula presented] in the Lq(Ω;⊗εkE)-norm, provided that (i) ξ∈Lkq(Ω;E) and (ii) q∈[p,∞), where p∈[1,2] is the Rademacher type of E. By using the fact that Rademacher averages are dominated by Gaussian sums combined with a version of Slepian's inequality for Gaussian processes due to Fernique, we moreover derive corresponding results for multilevel Monte Carlo methods, including a rigorous error estimate in the Lq(Ω;⊗εkE)-norm and the optimization of the computational cost for a given accuracy. Whenever the type of the Banach space E is p=2, our findings coincide with known results for Hilbert space valued random variables. We illustrate the abstract results by three model problems: second-order elliptic PDEs with random forcing or random coefficient, and stochastic evolution equations. In these cases, the solution processes naturally take values in non-Hilbertian Banach spaces. Further applications, where physical modeling constraints impose a setting in Banach spaces of type p<2, are indicated.","Injective tensor product; Multilevel Monte Carlo; Rademacher averages; Type of Banach space","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:90d516ce-efcc-4c71-bdcb-de885c7d1a72","http://resolver.tudelft.nl/uuid:90d516ce-efcc-4c71-bdcb-de885c7d1a72","DESCAN: Censorship-resistant indexing and search for Web3","de Vos, M.A. (TU Delft Data-Intensive Systems); Ishmaev, G. (TU Delft Data-Intensive Systems); Pouwelse, J.A. (TU Delft Data-Intensive Systems)","","2024","The popularity of blockchain technology has bootstrapped many “Web3” applications, e.g., Ethereum and IPFS, that apply distributed ledger technology to store transactions. The amount of transactions generated and stored in such Web3 applications is significant and, in its raw form, usually not searchable by users. Existing Web3 transaction indexing and search engines are predominantly centralized and, therefore, can manipulate search results or censor particular queries. With the proliferation of Web3 transactions and applications, a decentralized and censorship-resistant search primitive is becoming essential. We present DESCAN, a decentralized and censorship-resistant indexing and search engine for Web3. Users index their local Web3 transactions using custom rules that output triplets. Generated triplets are bundled in a distributed transaction graph that is searchable by other users. To coordinate search and distribute the storage of the transaction graph over peers in the network, we build upon a Skip Graph (SG) data structure. Since the Skip Graph does not provide any resilience against adversarial peers that censor searches, we propose four modifications to improve its robustness. We implement DESCAN and conduct experiments with up to 12 800 peers and 10 million Ethereum transactions. Our experiments show that DESCAN with our modifications enabled can tolerate 20% adversarial peers and 35% unresponsive peers without disruption. Moreover, we find that searches in DESCAN are usually completed well within a second, even when the network grows. Finally, we show that storage and network costs are evenly distributed amongst peers as the network grows.","Blockchain technology; Censorship resistance; Decentralized search; Decentralized systems; Skip graph; Web3","en","journal article","","","","","","","","","","","Data-Intensive Systems","","",""
"uuid:62668ef1-3a3f-4d58-9427-9d7faaab07a8","http://resolver.tudelft.nl/uuid:62668ef1-3a3f-4d58-9427-9d7faaab07a8","Measurement invariance of the driving inattention scale (ARDES) across 7 countries","Castro, Candida (Universidad de Granada); Pablo Doncel, P. (Universidad de Granada); Ledesma, Rubén D. (Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Universidad Nacional de Mar del Plata); Montes, Silvana A. (Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Universidad Nacional de Mar del Plata); Oviedo-Trespalacios, O. (TU Delft Safety and Security Science); Daniela Barragan, D. (George Mason University); Bianchi, Alessandra (Federal University of Paraná); Kauer, Natalia (Federal University of Paraná); Qu, Weina (Chinese Academy of Sciences); Padilla, Jose Luis (Universidad de Granada)","","2024","The Attention-Related Driving Errors Scale (ARDES) is a self-report measure of individual differences in driving inattention. ARDES was originally developed in Spanish (Argentina), and later adapted to other countries and languages. Evidence supporting the reliability and validity of ARDES scores has been obtained in various different countries. However, no study has been conducted to specifically examine the measurement invariance of ARDES measures across countries, thus limiting their comparability. Can different language versions of ARDES provide comparable measures across countries with different traffic regulations and cultural norms? To what extent might cultural differences prevent researchers from making valid inferences based on ARDES measures? Using Alignment Analysis, the present study assessed the approximate invariance of ARDES measures in seven countries: Argentina (n = 603), Australia (n = 378), Brazil (n = 220), China (n = 308). Spain (n = 310), UK (n = 298), and USA (n = 278). The three-factor structure of ARDES scores (differentiating driving errors occurring at Navigation, Manoeuvring and Control levels) was used as the target theoretical model. A fixed alignment analysis was conducted to examine approximate measurement invariance. 12.3 % of the intercepts and 0.8 % of the item-factor loadings were identified as non-invariant, averaging 8.6 % of non-invariance. Despite substantial differences among the countries, sample recruitment or representativeness, study results support resorting to ARDES measures to make comparisons across the country samples. Thus, the range of cultures, laws and collision risk across these 7 countries provides a demanding assessment for a cultural-free inattention while-driving. The alignment analysis results suggest that ARDES measures reach near equivalence among the countries in the study. We hope this study will serve as a basis for future cross-cultural research on driving inattention using ARDES.","Control errors; Distracted driver; Manoeuvring errors; Navigation errors; Planning errors; Proneness to distraction","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:6a421442-5f22-4c98-bc0f-e1dab5dff032","http://resolver.tudelft.nl/uuid:6a421442-5f22-4c98-bc0f-e1dab5dff032","Bringing Ecological Urbanism and Urban Political Ecology to transformative visions of water sensitivity in cities","Hädrich Silva, R. (TU Delft Urban Design); Zwarteveen, Margreet (IHE Delft Institute for Water Education); Stead, D. (TU Delft Spatial Planning and Strategy; Aalto University); Kuzniecow Bacchin, T. (TU Delft Urban Design)","","2024","Ecological Urbanism and Water Sensitive Urban Design have a central contribution to make in protecting and caring for people, nature and water in cities but readings of Urban Political Ecology evidence how ecological metaphors in urban design can easily translate into discriminatory urban development processes. This paper posits that for UPE to become meaningful for urban design practice, it is necessary to move beyond a critique. Instead, the insights of UPE should be pro-actively mobilized to develop a new vision of water sensitivity. The paper therefore identifies ways in which the key learnings of the critical social sciences, namely UPE, can be mobilized to support Water Sensitive Urban Design practice. How can ecological urbanists imagine new, more politically astute, forms of water sensitive living, charting design processes that not just recognize but also actively question and challenge uneven socio-ecological dynamics? In answering this question, the goal of this article is to make use of critique from UPE to influence Ecological Urbanists' goals and activate their political alignment with agendas that prioritize social equity. In imagining a new form of WSUD, we tried as much as possible not to over-instrumentalize UPE by rejecting the suggestion that some UPE ‘lessons’ or ‘insights’ could simply be inserted into ecological urbanism. On a different direction, we argue for a different emphasis in WSUD that does not deny the causes of current environmental degradation, pollution and depletion but, on the contrary, actively takes issue with and challenges the extractive and exploitative roots of contemporary urbanization processes.","Ecological Urbanism; Social justice; Urban ecology; Urban Political Ecology; Water Sensitive Urban Design","en","journal article","","","","","","","","","","","Urban Design","","",""
"uuid:e311e1fe-f222-4dbb-92e3-8cbf1ae9f751","http://resolver.tudelft.nl/uuid:e311e1fe-f222-4dbb-92e3-8cbf1ae9f751","Effect of microporous layer structural parameters on heat and mass transfer in proton exchange membrane fuel cells","Zhang, Zhenya (Zhengzhou University of Light Industry); Mao, Jia (Zhengzhou University of Light Industry); Wei, Houyu (Zhengzhou University of Light Industry); Cheng, Chuanxiao (Zhengzhou University of Light Industry); Liu, Zhengxuan (TU Delft Design & Construction Management)","","2024","Proton exchange membrane fuel cells offer promising clean energy solutions for various applications. However, their performance relies heavily on the properties of the microporous layer, which plays a crucial role in transporting and distributing the components in the fuel cell. To date, the potential for optimising the microporous layer material structural parameters to enhance the fuel cell performance remains largely unexplored. This study aims to fill this research gap by conducting a comprehensive investigation of the effects of different microporous layer material structural parameters on the heat and mass transfer in the membrane electrode assembly. MATLAB was used for optimising the performance of the fuel cell components. The results show that increasing the microporous layer thickness from 5 to 50 μm significantly affects the species transport, leading to a substantial reduction in the molar fraction of H2 and O2 at the electrochemical reaction sites. Furthermore, the distribution of the liquid water saturation inside the fuel cell is influenced by the porosity and permeability of the microporous layer. By increasing the porosity from 0.3 to 0.6, the liquid water saturation at the interface of the catalyst layer and microporous layer decreases by 0.52 % and 1.12 % at output voltages of 0.5 V and 0.7 V, respectively. This reduction enhances the efficiency of internal water transport. Moreover, reducing the permeability of the microporous layer from 2 × 10-12 to 1 × 10-13 at 0.5 V and 0.7 V leads to an increase in liquid water saturation at the interface of the proton exchange membrane and the catalyst layer by 1.49 % and 0.74 %, respectively, causing hindrance to the transport of internal liquid water. This study provides valuable insights into the interplay between the properties of the microporous layer material properties and heat and mass transfer characteristics in proton exchange membrane fuel cell.","Fuel cell efficiency; Heat and mass transfer; Microporous layer; Performance optimization; Proton exchange membrane fuel cells","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:65ffe8a9-4bed-47d4-a021-9e1d85f3c564","http://resolver.tudelft.nl/uuid:65ffe8a9-4bed-47d4-a021-9e1d85f3c564","High dielectric filler for all-solid-state lithium metal battery","Wang, C. (TU Delft RST/Storage of Electrochemical Energy; The Hong Kong Polytechnic University); Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Bannenberg, L.J. (TU Delft RID/TS/Instrumenten groep); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Thijs, M.A. (TU Delft RID/TS/Technici Pool); Boshuizen, B. (TU Delft ChemE/O&O groep); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2024","Lithium metal with its high theoretical capacity and low negative potential is considered one of the most important candidates to raise the energy density of all-solid-state batteries. However, lithium filament growth and its induced solid electrolyte decomposition pose severe challenges to realize a long cycle life. Here, dendrite growth in solid-state Li metal batteries is alleviated by introducing a high dielectric material, barium titanate, as a filler that removes the electric field gradients that catalyze dendrite formation. In symmetrical Li-metal cells, this results in a very small over-potential of only 48 mV at a relatively high current density of 1 mA cm−2, when cycling a capacity of 2 mA h cm−2 during 1700 h. The high dielectric filler improves the Coulombic efficiency and cycle life of full cells and suppresses electrolyte decomposition as indicated by solid-state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) measurements. This indicates that the high dielectric filler can suppress dendrite formation, thereby reducing solid electrolyte decomposition reactions, resulting in the observed low overpotentials and improved cycling efficiency.","All-solid-state batteries; Dendrite-free; Electrolyte decomposition; High dielectric filler; Li-metal anode","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:2a32c9c1-f2df-4127-986a-766cc7c2af98","http://resolver.tudelft.nl/uuid:2a32c9c1-f2df-4127-986a-766cc7c2af98","Similarity learning hidden semi-Markov model for adaptive prognostics of composite structures","Eleftheroglou, N. (TU Delft Structural Integrity & Composites; University of Patras); Galanopoulos, Georgios (University of Patras); Loutas, Theodoros (University of Patras)","","2024","Data-driven methodologies have found increasing usage in the last decade for remaining useful life (RUL) prognostics of composite materials utilizing structural health monitoring (SHM) data. Of particular interest is the reliable RUL prediction in cases where the end-of-life is not in between the extreme values within the testing dataset. For example, when unexpected phenomena that severely compromise the structural integrity occur during the service life. Such cases are often referred as outliers and the RUL prognosis based on a data-driven model that learns from past data is often erroneous. This study addresses this challenge by proposing a new stochastic model; the Similarity Learning Hidden Semi Markov Model (SLHSMM), an extension of the Non-Homogenous Hidden Semi Markov Model (NHHSMM). Through the utilization of a nonparametric discrete distribution, which characterizes the similarity between the testing structure and the training structures, a dynamic re-estimation process is employed. This process assigns higher importance to the training structures that display greater similarity to the testing one. As a result, the estimated parameters effectively capture the specific characteristics of the testing structure. The training and testing SHM data sets consist of strain measurements collected from a case study where carbon–epoxy single-stringered panels, are subjected to constant, variable, and random amplitude fatigue loading until failure. RUL estimations from the SLHSMM, the NHHSMM, and the Gaussian Process Regression (GPR) are compared. The SLHSMM clearly outperforms its classical counterpart and GPR providing more accurate outlier and inlier prognostics, demonstrating its capability to adapt to unexpected phenomena and integrate unforeseen data into a prognostic platform.","Adaptive prognostics; Composites; HSMM; Markov models; PHM; Prognostics; Remaining useful life","en","journal article","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:c7d08b53-d007-4270-9c86-8bc1c0736de1","http://resolver.tudelft.nl/uuid:c7d08b53-d007-4270-9c86-8bc1c0736de1","Metal- and covalent-organic framework mixed matrix membranes for CO2 separation: a perspective on stability and scalability","Shan, M. (TU Delft ChemE/Transport Phenomena; Zhengzhou University); Geng, Xiumei (Zhengzhou University); Imaz, Inhar (BIST); Broto-Ribas, Anna (BIST); Ortín-Rubio, Borja (BIST); Maspoch, Daniel (BIST; Catalan Institution for Research and Advanced Studies (ICREA)); Ansaloni, Luca (SINTEF Industry); Peters, Thijs A. (SINTEF Industry); Tena, Alberto (University of Twente; University of Valladolid); Boerrigter, Marcel E. (LEITAT Technological Center, Barcelona); Vermaas, D.A. (TU Delft ChemE/Transport Phenomena)","","2024","Membrane technology has attracted great industrial interest in carbon capture and separation owing to the merits of energy-efficiency, environmental friendliness and low capital investment. Conventional polymeric membranes for CO2 separation suffer from the trade-off between permeability and selectivity. Introducing porous fillers in polymers is one approach to enhance membrane separation performance. Metal-organic frameworks (MOFs), with ordered porous structure and diverse chemical functionalities, are promising fillers to prepare mixed matrix membranes (MMMs) for CO2 separation. However, the main issue of MOF based MMMs in industry is their stability and processability. This review analyses recent work on stable and scalable MOF based MMMs for CO2 separation. The typical stable MOFs, MOF-based MMMs and the scalable MOF synthesis are summarized. A large number of MOF-based MMM suffer from instability upon exposure to contaminants. For that reason, we also discuss the use of covalent organic frameworks (COFs) as an alternative to prepare MMMs for CO2 separation, considering their excellent stability and good compatibility with polymers. Finally, a brief conclusion and current challenges on obtaining scalable and stable MMMs are outlined. This review may provide some guidance for designing high performance MMMs for industrial CO2 capture and separation to help achieving carbon neutrality.","","en","review","","","","","","","","","","","ChemE/Transport Phenomena","","",""
"uuid:b301a6df-f13c-4839-a2b8-41199578a77e","http://resolver.tudelft.nl/uuid:b301a6df-f13c-4839-a2b8-41199578a77e","The relation between proximity to and characteristics of green spaces to physical activity and health: A multi-dimensional sensitivity analysis in four European cities","Cardinali, M. (TU Delft Heritage & Architecture; OWL, University of Applied Sciences and Arts); Beenackers, Mariëlle A. (Erasmus MC); van Timmeren, A. (TU Delft Environmental Technology and Design); Pottgiesser, U. (TU Delft Heritage & Architecture; OWL, University of Applied Sciences and Arts)","","2024","Introduction: Non-communicable diseases are the global disease burden of our time, with physical inactivity identified as one major risk factor. Green spaces are associated with increased physical activity of nearby residents. But there are still gaps in understanding which proximity and what characteristics of green spaces can trigger physical activity. This study aims to unveil these differences with a rigorous sensitivity analysis. Methods: We gathered data on self-reported health and physical activity from 1365 participants in selected neighbourhoods in Porto, Nantes, Sofia, and Høje-Taastrup. Spatial data were retrieved from OpenStreetMap. We followed the PRIGSHARE guidelines to control for bias. Around the residential addresses, we generated seven different green space indicators for 15 distances (100–1500 m) using the AID-PRIGSHARE tool. We then analysed each of these 105 green space indicators together with physical activity and health in 105 adjusted structural equation models. Results: Green space accessibility and green space uses indicators showed a pattern of significant positive associations to physical activity and indirect to health at distances of 1100 m or less, with a peak at 600 m for most indicators. Greenness in close proximity (100 m) had significant positive effects on physical activity and indirect effects on health. Surrounding greenness showed positive direct effects on health at 500–1100 m and so do green corridors in 800 m network distance. In contrast, a high quantity of green space uses, and surrounding greenness measured in a larger radius (1100–1500 m) showed a negative relationship with physical activity and indirect health effects. Conclusions: Our results provide insight into how green space characteristics can influence health at different scales, with important implications for urban planners on how to integrate accessible green spaces into urban structures and public health decision-makers on the ability of green spaces to combat physical inactivity.","Behaviour; Greenspace; Mediator; Public health; Sedentary lifestyle","en","journal article","","","","","","","","","","","Heritage & Architecture","","",""
"uuid:355aa0ba-550c-4b66-b2c0-f6eaaf3dac74","http://resolver.tudelft.nl/uuid:355aa0ba-550c-4b66-b2c0-f6eaaf3dac74","Antioxidant-driven activity and stability enhancement in multiphase bicarbonate hydrogenation catalysis with a Ru-PNP pincer complex","Hirano, Makoto (Nitto Denko Corporation); Wada, Kazuhito (Nitto Denko Corporation); Matsuda, Hirokazu (Nitto Denko Corporation); Pidko, E.A. (TU Delft ChemE/Inorganic Systems Engineering)","","2024","Herein, we present a practical strategy to enhance the performance of a multiphase system for bicarbonate hydrogenation based on a molecular Ru-PNP pincer catalyst. This study demonstrates that the use of organic antioxidants not only mitigates catalyst degradation but also significantly boosts its intrinsic activity. This enables efficient catalyst recycling at ultra-low concentrations. Systematic screening and optimization of a range of organic antioxidants has identified TDTBP (tris(2,4-di-tert-butylphenyl) phosphite) as being exceptionally efficient in stabilizing and enhancing the performance of the Ru-PNP catalyst. With the optimized system an unprecedented integral turnover frequency (TOF) of 115,000 h−1 and a total turnover number (TTON) of 9.43×106 across four recycling tests were demonstrated, conducted at a reaction temperature of 90 ºC and H2 pressure of 50 bar. These findings represent a substantial advancement in sustainable formate/formic acid production, offering a scalable and highly efficient method suitable for industrial-scale application.","Antioxidant; Bicarbonate hydrogenation; Catalyst Stabilization; Multiphase system; Pincer complexes","en","journal article","","","","","","","","","","","ChemE/Inorganic Systems Engineering","","",""
"uuid:a1eefa48-1740-4350-a97c-f058a845885a","http://resolver.tudelft.nl/uuid:a1eefa48-1740-4350-a97c-f058a845885a","GRACE and GRACE Follow-On Gravity Observations of Intermediate-Depth Earthquakes Contrasted With Those of Shallow Events","Han, Shin-Chan (The University of Newcastle, Australia); Sauber, Jeanne (NASA Goddard Space Flight Center); Broerse, D.B.T. (TU Delft Physical and Space Geodesy); Pollitz, Fred (U.S. Geological Survey); Okal, Emile (Northwestern University); Jeon, Taehwan (Seoul National University); Seo, Ki Weon (Seoul National University); Stanaway, Richard (Papua New Guinea University of Technology)","","2024","Earthquakes involve mass redistribution within the solid Earth and the ocean, and as a result, perturb the Earth's gravitational field. For most of the shallow (<60 km) earthquakes with Mw > 8.0, the GRACE satellite gravity measurements suggest considerable volumetric disturbance of rocks. At a spatial scale of hundreds of km, the effect of volumetric change exceeds gravity change by vertical deformation; for example, negative gravity anomalies associated with volumetric expansion are characteristic patterns after shallow thrust events. In this study, however, we report contrasting observations of gravity change from two intermediate-depth (100–150 km) earthquakes of 2016 & 2017 Mw 8.0 (two combined) Papua New Guinea thrust faulting events and 2019 Mw 8.0 Peru normal faulting and highlight the importance of compressibility in earthquake deformation. The combined 2016/17 thrust events resulted in a positive gravity anomaly of 5–6 microGal around the epicenter, while the 2019 normal faulting produced a negative gravity anomaly of 3–4 microGal. Our modeling found that these gravity changes are manifestation of vertical deformation with limited volumetric change, distinct from gravity changes after the shallow earthquakes. The stronger resistance of rocks to volume change at intermediate-depth results in largely incompressible deformation and thus in a gravity change dominated by vertical deformation. In addition, malleable rocks under high pressure and temperature at depth facilitated substantial afterslip and/or fast viscoelastic relaxation causing additional vertical deformation and gravity change equivalent to the coseismic change. For the Papua New Guinea events, this means that postseismic relaxation enhanced coseismic uplift and relative sea level decrease.","deformation; earthquakes; GRACE; gravity change; viscoelastic relaxation","en","journal article","","","","","","","","","","","Physical and Space Geodesy","","",""
"uuid:afb15a01-05a0-4941-8c40-e194516209bd","http://resolver.tudelft.nl/uuid:afb15a01-05a0-4941-8c40-e194516209bd","Interparticle friction in sheared dense suspensions: Comparison of the viscous and frictional rheology descriptions","Peerbooms, W. (TU Delft Multi Phase Systems); Nadorp, Tim (Student TU Delft); van der Heijden, A.E.D.M. (TU Delft Complex Fluid Processing; TNO); Breugem, W.P. (TU Delft Multi Phase Systems)","","2024","In the literature, two different frameworks exist for describing the rheology of solid/liquid suspensions: (1) the “viscous” framework in terms of the relative suspension viscosity, ηr, as a function of the reduced solid volume fraction, f=fm, with fm the maximum flowable packing fraction, and (2) the “frictional” framework in terms of a macroscopic friction coefficient, μ, as a function of the viscous number, Iv, defined as the ratio of the viscous shear to the wall-normal particle stress. Our goal is to compare the two different frameworks, focusing on the effect of friction between particles. We have conducted a particle-resolved direct numerical simulation study of a dense non-Brownian suspension of neutrally buoyant spheres in slow plane Couette flow. We varied the bulk solid volume fraction from fb ¼ 0:1 to 0.6 and considered three different Coulomb friction coefficients: μc ¼ 0, 0.2, and 0.39. We find that ηr scales well with f=fm, with fm obtained from fitting the Maron–Pierce correlation. We also find that μ scales well with Iv. Furthermore, we find a monotonic relation between f=fm and Iv, which depends only weakly on μc. Since ηr ¼ μ=Iv, we thus find that the two frameworks are largely equivalent and that both account implicitly for Coulomb friction. However, we find that the normal particle stress differences, N1 and N2, when normalized with the total shear stress and plotted against either f=fm or Iv, remain explicitly dependent on μc in a manner that is not yet fully understood.","","en","journal article","","","","","","","","","","","Multi Phase Systems","","",""
"uuid:2a454ba8-3134-417a-83a4-a665772c9a69","http://resolver.tudelft.nl/uuid:2a454ba8-3134-417a-83a4-a665772c9a69","Spatial lipidomics of coronary atherosclerotic plaque development in a familial hypercholesterolemia swine model","Slijkhuis, Nuria (Erasmus MC); Razzi, F. (TU Delft ChemE/Product and Process Engineering; Erasmus MC); Korteland, Suze Anne (Erasmus MC); Heijs, Bram (Leiden University Medical Center); van Gaalen, Kim (Erasmus MC); Duncker, Dirk J. (Erasmus MC); van der Steen, A.F.W. (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Verweij group; Erasmus MC; Chinese Academy of Sciences); van Steijn, V. (TU Delft ChemE/Product and Process Engineering); van Beusekom, Heleen M.M. (Erasmus MC); van Soest, G. (TU Delft Biomechanical Engineering; Massachusetts General Hospital; Erasmus MC)","","2024","Coronary atherosclerosis is caused by plaque build-up, with lipids playing a pivotal role in its progression. However, lipid composition and distribution within coronary atherosclerosis remain unknown. This study aims to characterize lipids and investigate differences in lipid composition across disease stages to aid in the understanding of disease progression. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was used to visualize lipid distributions in coronary artery sections (n ¼ 17) from hypercholesterolemic swine. We performed histology on consecutive sections to classify the artery segments and to investigate colocalization between lipids and histological regions of interest in advanced plaque, including necrotic core and inflammatory cells. Segments were classified as healthy (n ¼ 6), mild (n ¼ 6), and advanced disease (n ¼ 5) artery segments. Multivariate data analysis was employed to find differences in lipid composition between the segment types, and the lipids' spatial distribution was investigated using non-negative matrix factorization (NMF). Through this process, MALDI-MSI detected 473 lipid-related features. NMF clustering described three components in positive ionization mode: triacylglycerides (TAG), phosphatidylcholines (PC), and cholesterol species. In negative ionization mode, two components were identified: one driven by phosphatidylinositol(PI)(38:4), and one driven by ceramidephosphoethanolamine(36:1). Multivariate data analysis showed the association between advanced disease and specific lipid signatures like PC(O-40:5) and cholesterylester(CE)(18:2). Ether-linked phospholipids and LysoPC species were found to colocalize with necrotic core, and mostly CE, ceramide, and PI species colocalized with inflammatory cells. This study, therefore, uncovers distinct lipid signatures correlated with plaque development and their colocalization with necrotic core and inflammatory cells, enhancing our understanding of coronary atherosclerosis progression.","Atherosclerosis; dyslipidemias; familial hypercholesterolemia; histology; inflammation; lipids; lipids/chemistry; mass spectrometry imaging; plaque progression; vascular biology","en","journal article","","","","","","","","","","Biomechanical Engineering","ChemE/Product and Process Engineering","","",""
"uuid:8fe6849e-b95d-44ba-a03b-217552275d30","http://resolver.tudelft.nl/uuid:8fe6849e-b95d-44ba-a03b-217552275d30","Identification of an overactuated deformable mirror system with unmeasured outputs","Tacx, Paul (Eindhoven University of Technology); Habraken, Roel (Eindhoven University of Technology; TNO); Witvoet, Gert (Eindhoven University of Technology; TNO); Heertjes, Marcel (Eindhoven University of Technology; ASML); Oomen, T.A.E. (TU Delft Team Jan-Willem van Wingerden; Eindhoven University of Technology)","","2024","Next-generation deformable mirrors are envisaged to exhibit low-frequency flexible dynamics and to contain a large number of spatially distributed actuators due to increasingly stringent performance requirements. The increasingly complex system characteristics necessitate identifying the flexible dynamic behavior for design validation and next-generation control. The aim of this paper is to develop a unified approach for the identification of mechanical systems with a large number of spatially distributed actuators and a limited number of sensors. A frequency domain-based approach using local modeling techniques is developed. The modal modeling framework is employed to analyze the design and create outputs that were not measured. The proposed approach is applied to an experimental deformable mirror case study that illustrates the effectiveness of the proposed approach.","Adaptive optics; Local parametric modeling; Mechanical models; Mechatronics; Modal analysis; Motion control","en","journal article","","","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:93536dca-ae2c-483a-be8f-03616d14bc71","http://resolver.tudelft.nl/uuid:93536dca-ae2c-483a-be8f-03616d14bc71","Peanut shaped auxetic cementitious cellular composite (ACCC)","Xie, J. (TU Delft Materials and Environment); Xu, Y. (TU Delft Materials and Environment); Meng, Z. (TU Delft Materials and Environment); Liang, M. (TU Delft Materials and Environment); Wan, Z. (TU Delft Materials and Environment); Šavija, B. (TU Delft Materials and Environment)","","2024","Auxetic cementitious cellular composites (ACCCs) exhibit desirable mechanical properties (e.g., high fracture resistance and energy dissipation), due to their unique deformation characteristics. In this study, a new type of cementitious auxetic material, referred to as peanut shaped ACCC, has been designed and subsequently architected using additive manufacturing techniques. Two peanut shaped ACCCs specimens with different pseudo-minor axes have been tested under uniaxial compression with Digital Image Correlation (DIC) to assess their compressive behavior, peak strength, Poisson's ratio, and energy dissipation capacity. Additionally, cyclic tests were conducted to investigate their compressive resilience properties, further elucidated through microstructural analysis using a digital optical microscope. The mechanical test results were also compared with those of previously developed elliptical-shaped ACCCs. Furthermore, a numerical model was used to simulate the mechanical behavior of peanut shaped ACCCs under uniaxial compression, and showed a good agreement with the experimental data. The auxetic behavior observed in peanut shaped ACCCs arises from the rotation of sections facilitated by fiber bridging at the ligament of adjacent holes within the cementitious unit cell. In comparison to elliptical-shaped ACCCs, peanut shaped ACCCs can exhibit a slightly more negative Poisson's ratio and mitigate stress concentration. The reduction of stress concentration enables peanut shaped ACCCs to dissipate substantial energy, showcasing enhanced ductility and toughness. In cyclic tests, peanut shaped ACCCs exhibit superior recoverable deformation elasticity, attributed to robust fiber bridging capacity. The exceptional mechanical properties exhibited by peanut shaped ACCCs offer a scalable solution for developing energy-absorbent and multifunctional cementitious materials for smart infrastructure.","Additive manufacturing; Auxetic cementitious cellular composites; CDP model; Compressive resilience; Cyclic test; Energy dissipation","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:765c3f37-44fe-4247-9a28-50645ac03819","http://resolver.tudelft.nl/uuid:765c3f37-44fe-4247-9a28-50645ac03819","Fair resource allocation in virtualized O-RAN platforms","Aslan, F.A. (TU Delft Networked Systems); Iosifidis, G. (TU Delft Networked Systems); Ayala-Romero, Jose A. (NEC Laboratories Europe); Garcia-Saavedra, Andres (NEC Laboratories Europe); Costa-Perez, Xavier (NEC Laboratories Europe; ICREA)","","2024","O-RAN systems and their deployment in virtualized general-purpose computing platforms (O-Cloud) constitute a paradigm shift expected to bring unprecedented performance gains. However, these architectures raise new implementation challenges and threaten to worsen the already-high energy consumption of mobile networks. This paper presents first a series of experiments which assess the O-Cloud's energy costs and their dependency on the servers' hardware, capacity and data traffic properties which, typically, change over time. Next, it proposes a compute policy for assigning the base station data loads to O-Cloud servers in an energy-efficient fashion; and a radio policy that determines at near-real-Time the minimum transmission block size for each user so as to avoid unnecessary energy costs. The policies balance energy savings with performance, and ensure that both of them are dispersed fairly across the servers and users, respectively. To cater for the unknown and time-varying parameters affecting the policies, we develop a novel online learning framework with fairness guarantees that apply to the entire operation horizon of the system (long-Term fairness). The policies are evaluated using trace-driven simulations and are fully implemented in an O-RAN compatible system where we measure the energy costs and throughput in realistic scenarios.","Energy Efficiency; Fairness; Mobile Networks; O-RAN; Online Learning; Regret; Resource Management","en","journal article","","","","","","","","","","","Networked Systems","","",""
"uuid:bd302b37-4283-419c-840c-22df51deb234","http://resolver.tudelft.nl/uuid:bd302b37-4283-419c-840c-22df51deb234","Who's got my back? Measuring the adoption of an internet-wide BGP RTBH Service","Anghel, R.I. (TU Delft Organisation & Governance); Zhauniarovich, Y. (TU Delft Organisation & Governance); Hernandez Ganan, C. (TU Delft Organisation & Governance)","","2024","Distributed Denial-of-Service (DDoS) attacks continue to threaten the availability of Internet-based services. While countermeasures exist to decrease the impact of these attacks, not all operators have the resources or knowledge to deploy them. Alternatively, anti-DDoS services such as DDoS clearing houses and blackholing have emerged. Unwanted Traffic Removal Service (UTRS), being one of the oldest community-based anti-DDoS services, has become a global free collaborative service that aims at mitigating major DDoS attacks through the Border Gateway Protocol (BGP). Once the BGP session with UTRS is established, UTRS members can advertise part of the prefixes belonging to their AS to UTRS. UTRS will forward them to all other participants, who, in turn, should start blocking traffic to the advertised IP addresses. In this paper, we develop and evaluate a methodology to automatically detect UTRS participation in the wild. To this end, we deploy a measurement infrastructure and devise a methodology to detect UTRS-based traffic blocking. Using this methodology, we conducted a longitudinal analysis of UTRS participants over ten weeks. Our results show that at any point in time, there were 562 participants, including multihomed, stub, transit, and IXP ASes. Moreover, we surveyed 245 network operators to understand why they would (not) join UTRS. Results show that threat and coping appraisal significantly influence the intention to participate in UTRS.","BGP; DDoS; Internet measurements; RTBH; UTRS","en","journal article","","","","","","","","","","","Organisation & Governance","","",""
"uuid:00e08af7-bdca-4f56-8889-cfa52ee418de","http://resolver.tudelft.nl/uuid:00e08af7-bdca-4f56-8889-cfa52ee418de","Multiple phase rifting and subsequent inversion in the West Netherlands Basin: implications for geothermal reservoir characterization","Weert, Annelotte (Università degli Studi di Napoli Federico II); Ogata, Kei (Università degli Studi di Napoli Federico II); Vinci, Francesco (PanTerra Geoconsultants B.V.); Leo, Coen (Geoleo B.V. Consultancy); Bertotti, G. (TU Delft Applied Geology); Amory, Jerome (PanTerra Geoconsultants B.V.); Tavani, Stefano (Università degli Studi di Napoli Federico II; Consiglio Nazionale delle Ricerche (IGAG-CNR))","","2024","Aiming to contribute to the energy transition, this study provides an integrated picture of the geothermal system hosted in the West Netherlands Basin and shows how the reconstruction of the basin's geological history can contribute to the correct exploration and exploitation of its geothermal resources. In the West Netherlands Basin, the main geothermal targets are found in the Cretaceous and Jurassic strata that were deposited during the rifting and post-rifting stages and were deformed during the subsequent basin inversion. Despite multiple studies on the tectonic setting, the timing and tectono-stratigraphic architecture of the rift system and its overall control on the development and evolution of geothermal systems are still to be fully deciphered. In this study, a detailed seismo-stratigraphic interpretation of the syn- and post-rift intervals in the West Netherlands Basin will be given within the framework of geothermal exploration. A recently released and reprocessed 3D seismic cube is used, covering a large portion of the onshore section of the basin. We identified two major Jurassic rifting episodes and a Late Cretaceous inversion event. During the Jurassic rifting phases, the compartmentalization of the basin and the creation of accommodation space led to the deposition of the Late Jurassic Nieuwerkerk Formation, which is the main regional geothermal producing target. Within this formation, we individuate growth synclines located in the central portions of the Jurassic half-grabens as sites that show good potential for geothermal exploration.","","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:10f466d7-2b4a-45a5-984f-366f41028a15","http://resolver.tudelft.nl/uuid:10f466d7-2b4a-45a5-984f-366f41028a15","Rheology-based wall function approach for wall-bounded turbulent flows of Herschel–Bulkley fluids","Yusufi, B.K. (TU Delft Sanitary Engineering); Kapelan, Z. (TU Delft Sanitary Engineering); Mehta, D. (TU Delft Sanitary Engineering)","","2024","Modeling fully developed turbulent flow for Herschel–Bulkley (HB) fluids in pipes is a long-standing challenge. Existing semi-empirical, theoretical, and numerical methods are either inconsistent with experimental data or are validated for low Reynolds numbers. This study focuses on validating a novel approach using rheology-based wall functions within Reynolds-averaged Navier–Stokes solvers. Simulations of wall shear stress and velocity profiles were conducted across a wide range of Reynolds numbers using a single-phase HB fluid, with measurements taken both upstream and downstream of a 90 pipe bend. Two turbulence closure models, the k–e model and the Reynolds stress model, were employed with the wall function implemented as a specified shear boundary condition. Results demonstrate significant improvements over the Newtonian-based models, such as standard wall function by Launder–Spalding or with available semi-empirical models, achieving strong statistical correlations and minimal deviation (from the experimental findings) at high Reynolds numbers. The study also examines the utility of the wall viscosity Reynolds number and assesses the reliability of semi-empirical models for HB fluids. These findings offer valuable insights for enhancing modeling accuracy in complex fluid flow scenarios, with potential applications spanning industries like mining, chemical processing, petroleum transportation, and sanitation systems, providing practical alternatives to costly experimental procedures in pipe systems.","","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:f75249f5-4680-4546-90eb-3fdc08e4a4d6","http://resolver.tudelft.nl/uuid:f75249f5-4680-4546-90eb-3fdc08e4a4d6","Global dynamics and topology of two-phase mixing layer flow through simultaneous gas and liquid velocity measurements","Della Pia, A. (Università degli Studi di Napoli Federico II; International School for Advanced Studies); Michelis, Theodorus (TU Delft Aerodynamics); Chiatto, Matteo (Università degli Studi di Napoli Federico II); Kotsonis, M. (TU Delft Aerodynamics); De Luca, Luigi (Università degli Studi di Napoli Federico II)","","2024","This study reports the first time-resolved particle image velocimetry characterization of a planar two-phase mixing layer flow, whose velocity field is measured simultaneously in gas and liquid streams. Two parallel air and water flows meet downstream of a splitter plate, giving rise to an initially spanwise invariant configuration. The aim is to elucidate further the mechanisms leading to the flow breakup in gas-assisted atomization. The complete experimental characterization of the velocity field represents a database that could be used in data-driven reduced-order models to investigate the global behaviour of the flow system. After the analysis of a selected reference case, a parametric study of the flow behaviour is performed by varying the liquid and gas Reynolds numbers, and as a consequence also the gas-to-liquid dynamic pressure ratio , shedding light on both time-averaged (mean) and unsteady velocity fields. In the reference case, it is shown that the mean flow exhibits a wake region just downstream of the splitter plate, followed by the development of a mixing layer. By increasing both and, the streamwise extent of the wake decreases and eventually vanishes, the flow resulting in a pure mixing layer regime. The spectral analysis of the normal-to-flow velocity fluctuations outlines different flow regimes by variation of the governing parameters, giving more insights into the global characteristics of the flow field. As a major result, it is found that at high and values, the velocity fluctuations are characterized by low-frequency temporal oscillations synchronized in several locations within the flow field, which suggest the presence of a global mode of instability. The proper orthogonal decomposition of velocity fluctuations, performed in both gas and liquid phases, reveals finally that the synchronized oscillations are associated with a low-frequency dominant flapping mode of the gas-liquid interface. Higher-order modes correspond to interfacial wave structures travelling with the so-called Dimotakis velocity. For lower gas Reynolds numbers, the leading modes describe higher frequency fingers shedding at the interface.","gas/liquid flow; shear waves","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-19","","","Aerodynamics","","",""
"uuid:0b60a8c3-dcfc-4325-b3c8-03b6dea4865c","http://resolver.tudelft.nl/uuid:0b60a8c3-dcfc-4325-b3c8-03b6dea4865c","Geometric effects on impact mitigation in architected auxetic metamaterials","Gärtner, T. (TU Delft Applied Mechanics; TNO); van den Boom, S. J. (TNO); Weerheijm, J. (TU Delft Applied Mechanics); Sluys, Lambertus J. (TU Delft Applied Mechanics)","","2024","Lightweight materials used for impact mitigation must be able to resist impact and absorb the maximum amount of energy from the impactor. Auxetic materials have the potential to achieve high resistance by drawing material into the impact zone and providing higher indentation and shear resistance. However, these materials must be artificially designed, and the large deformation dynamic effects of the created structures must be taken into consideration when deciding on a protection concept. Despite their promise, little attention has been given to understanding the working mechanisms of high-rate and finite deformation effects of architected auxetic lattice structures. This study compares the static and dynamic elastic properties of different auxetic structures with a honeycomb structure, a typical non-auxetic lattice, at equivalent mass and stiffness levels. In this study, we limit the investigation to elastic material behavior and do not consider contact between the beams of the lattices. It is demonstrated that the equivalent static and dynamic properties of individual lattices at an undeformed state are insufficient to explain the variations observed in impact situations. In particular, the initial Poisson's ratio does not determine the ability of a structure to resist impact. To gain a thorough comprehension of the overall behavior of these structures during localized, high rate compression, the evolution of the elastic tangent properties under compression and shear deformation was monitored, leading to a more profound understanding. Observations made in one configuration of stiffness and mass are replicated and analyzed in related configurations.","Architected materials; Elasticity; Geometric nonlinearity; Impact mitigation; Lattice structures","en","journal article","","","","","","","","","","","Applied Mechanics","","",""
"uuid:1200e5a2-966c-44d8-ad2b-0084ac57b721","http://resolver.tudelft.nl/uuid:1200e5a2-966c-44d8-ad2b-0084ac57b721","On the Derivation of Closed-Form Expressions for Displacements, Strains, and Stresses Inside Poroelastic Reservoirs","Cornelissen, P. (TU Delft Reservoir Engineering; Wageningen University & Research); Meulenbroek, B.J. (TU Delft Mathematical Physics); Jansen, J.D. (TU Delft Reservoir Engineering)","","2024","We critically review the derivation of closed-form analytical expressions for elastic displacements, strains, and stresses inside a subsurface reservoir undergoing pore pressure changes using inclusion theory. Although developed decades ago, inclusion theory has been used recently by various authors to obtain fast estimates of depletion-induced and injection-induced fault stresses in relation to induced seismicity. We therefore briefly address the current geomechanical relevance of this method, and provide a numerical example to demonstrate its use to compute induced fault stresses. However, the main goal of our paper is to correct some erroneous assumptions that were made in earlier publications. While the final expressions for the poroelastic stresses in these publications were correct, their derivation contained conceptual mistakes due to the mathematical subtleties that arise because of singularities in the Green's functions. The aim of our paper is therefore to present the correct derivation of expressions for the strains and stresses inside an inclusion and to clarify some of the results of the aforementioned studies. Furthermore, we present two conditions that the strain field must satisfy, which can be used to verify the analytical expressions.","analytical solution; Green's function; inclusion theory; Leibniz integral rule; poroelasticity","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:36c414f7-3be2-4dd1-8f55-ccf156ff3981","http://resolver.tudelft.nl/uuid:36c414f7-3be2-4dd1-8f55-ccf156ff3981","A simple QP modification of the OC update to permit treatment of the topology design problem of self-weight","Munro, D.P. (TU Delft Computational Design and Mechanics)","","2024","This note communicates a simple modification of the optimality criteria (OC) design update—as found in well-known Matlab implementations of the classical topology design problem—to an update based on a quadratic program (QP) with a single linear constraint. This QP update is a special case of the dual of Falk, which in general accommodates multiple constraints, as discussed in the Appendix. It is demonstrated that the topology design problem of self-weight may be treated with judicious selection of the adaptive curvature term in the QP, without resorting to more sophisticated algorithms or material interpolation schemes. Theory is recited and an accordingly modified version of the canonical Matlab implementation is provided as supplementary material.","Design-dependent loads; Duality; Matlab; Optimality criteria (OC); Quadratic program (QP); Self-weight; Sequential approximate optimization (SAO); Topology optimization","en","journal article","","","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:e0e8fa53-2945-4152-b6a7-91244b228ed9","http://resolver.tudelft.nl/uuid:e0e8fa53-2945-4152-b6a7-91244b228ed9","Finite element-based framework to study the response of bituminous concrete pavements under different conditions","Kumar, Abhinav (Indian Institute of Technology Banaras Hindu University); Gupta, Ankit (Indian Institute of Technology Banaras Hindu University); Anupam, K. (TU Delft Pavement Engineering); Wagh, Vivek Pratap (Indian Institute of Technology Banaras Hindu University)","","2024","In most of developing countries across the world, pavement design is still based on an empirical approach that may result in premature failure or overdesigned pavements. A shift from an empirical to a semi-mechanistic or mechanistic approach is the need of modern time. In this regard, computational tools such as finite element (FE) are being successfully utilized to gain deeper insights because such tools have allowed researchers to study the complex behaviour of bituminous concrete (BC) materials. It is well recognized that BC material typically exhibits viscoelastic/visco-elasto-plastic behaviour depending on applied loading (including temperature) conditions. However, due to the complexity of the whole procedure yet many pavement design tools consider them as pure elastic material. The aim of this research is to develop FEM based simple and practical framework to evaluate the structural response of BC material with viscoelastic material characterization which can be an effective tool to predict field behaviour with commonly available pavement material tests. Such a framework will be helpful in analysing variations in the critical response of BC pavement with varied traffic loads and ambient temperatures. The framework provides a relatively simple procedure to obtain the viscoelastic parameters of BC mix with a creep compliance test conducted at different temperatures. It was concluded that Creep compliance data if pre-smoothened by the Power law model reduces mathematical optimization issues to some extent. Furthermore, with the obtained parameters, a 3-dimensional FE model was developed to obtain sensitivity to critical stresses, strains, and vertical deformations at desired conditions. Material characterization of unbound granular layers was evaluated through resilient modulus based on empirical relations. Analysis was carried out taking into consideration the traffic load, contact pressure, mix type, air-void, and temperature variation.","Creep compliance; Effect of air voids; Generalised Kelvin model; Indian traffic conditions; Resilient modulus","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:53eb54fe-2791-46de-8b8d-c10777e3cc27","http://resolver.tudelft.nl/uuid:53eb54fe-2791-46de-8b8d-c10777e3cc27","Assessing Angular Momentum, Kinetics, and Energetics of a Rigid Body Using a Single Inertial Measurement Unit","Zhang, Junhao (University of Twente); Muijzer, Frodo (University of Twente); Vallery, H. (TU Delft Biomechatronics & Human-Machine Control; Rheinisch-Westfälische Technische Hochschule; Erasmus MC); Veltink, Peter H. (University of Twente)","","2024","Angular momentum, kinetics, and energetics, including total mechanical energy and its rate of change in relation to power exchange, are important quantities when analyzing human motion in sports, physical labor, and rehabilitation. Inertial measurement units (IMU)-based motion capture (MOCAP) systems provide a portable solution for the ambulatory analysis of these quantities which optical MOCAP systems do not offer. Yet, evaluating IMU-based estimates of these quantities by referencing optical systems is limited by the fact that these systems only measure positions, not kinetic and energetic quantities. To evaluate the accuracy of an IMU-based method for estimating kinetic and energetic quantities without using any external reference, firstly, we propose an estimation method only using angular velocity and acceleration signals supplied by an IMU, and apply this to a single rigid body with known mass and inertia. Then, we propose a novel experimental validation method against physical conservation and action/reaction laws that apply during ballistic movements, using a suitably designed and reconfigurable rigid body with a structure of three orthogonal dumb-bells. The results demonstrated that we could estimate the angular momentum, kinetics, and energetics of a rigid body by only using angular velocity and acceleration signals of an IMU, and the estimation accuracy was well evaluated by the proposed validation method. However, the results showed that the errors in original IMU measurements under dynamic conditions especially concerning angular velocity, uncertainties in calculating rigid body parameters, and vibration propagation due to limited rigidity of tubes of the rigid body influenced the estimation accuracy.","Angular momentum; energetics; inertial measurement unit (IMU); kinetics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-22","","","Biomechatronics & Human-Machine Control","","",""
"uuid:3b2512f5-feee-49c0-8866-9e9ecae309cf","http://resolver.tudelft.nl/uuid:3b2512f5-feee-49c0-8866-9e9ecae309cf","Improving global digital elevation models using space-borne GEDI and ICESat-2 LiDAR altimetry data","Narin, O.G. (TU Delft Optical and Laser Remote Sensing; Afyon Kocatepe University); Abdikan, Saygin (Hacettepe University); Gullu, Mevlut (Afyon Kocatepe University); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing); Balik Sanli, Fusun (Yildiz Technical University); Yilmaz, Ibrahim (Afyon Kocatepe University)","","2024","Open source Global Digital Elevation Models (GDEMs) serve as an important base for studies in geosciences. However, these models contain vertical errors due to various reasons. In this study, data from two Satellite LiDAR altimetry systems, GEDI and ICESat-2, were used to improve the vertical accuracy of GDEMs. Three different machine learning methods, namely an Artificial Neural Network (ANN), Extreme Gradient Boosting (XGBoost), and a Convolutional Neural Network (CNN), were employed to improve existing DEM data with satellite LiDAR data. The methodology was tested in five areas with varying characteristics. Ground control data were selected from high accuracy DEMs generated from Airborne LiDAR and GNSS data. The use of ANN method improved the vertical accuracy of SRTM data from 6.45 to 3.72 m in Test area-4. Similarly, the CNN method demonstrated an improvement in the vertical accuracy of bare ground SRTM data increasing from 3.4 to 0.6 m in Test area-4. In Test area-5, the ANN method improved the vertical accuracy of SRTM data with slopes between 30 and 60%, increasing from 3.8 to 0.5 m. Notably, the results underscore the successful improvement of GDEMs across all test areas.","GEDI; Global digital elevation models; ICESat-2; machine learning","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:48abb16f-c037-4048-b642-8d60e8557d9a","http://resolver.tudelft.nl/uuid:48abb16f-c037-4048-b642-8d60e8557d9a","Accumulation of defense systems in phage-resistant strains of Pseudomonas aeruginosa","Martins Costa, A.R. (TU Delft BN/Stan Brouns Lab; Kavli institute of nanoscience Delft); van den Berg, D.F. (TU Delft BN/Stan Brouns Lab; Kavli institute of nanoscience Delft); Esser, J.Q. (TU Delft BN/Stan Brouns Lab; Kavli institute of nanoscience Delft); Muralidharan, A. (TU Delft BN/Stan Brouns Lab; Kavli institute of nanoscience Delft); van den Bossche, Halewijn (Kavli institute of nanoscience Delft); Estrada Bonilla, B.A. (TU Delft BN/Stan Brouns Lab; Kavli institute of nanoscience Delft); van der Steen, B.A. (TU Delft BN/Stan Brouns Lab; Kavli institute of nanoscience Delft); Haas, Pieter Jan (University Medical Center Utrecht); Brouns, S.J.J. (TU Delft BN/Stan Brouns Lab; Kavli institute of nanoscience Delft)","","2024","Prokaryotes encode multiple distinct anti-phage defense systems in their genomes. However, the impact of carrying a multitude of defense systems on phage resistance remains unclear, especially in a clinical context. Using a collection of antibiotic-resistant clinical strains of Pseudomonas aeruginosa and a broad panel of phages, we demonstrate that defense systems contribute substantially to defining phage host range and that overall phage resistance scales with the number of defense systems in the bacterial genome. We show that many individual defense systems target specific phage genera and that defense systems with complementary phage specificities co-occur in P. aeruginosa genomes likely to provide benefits in phage-diverse environments. Overall, we show that phage-resistant phenotypes of P. aeruginosa with at least 19 phage defense systems exist in the populations of clinical, antibiotic-resistant P. aeruginosa strains.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-23","","","BN/Stan Brouns Lab","","",""
"uuid:47aa5381-a5fd-407e-9485-ded81a03427b","http://resolver.tudelft.nl/uuid:47aa5381-a5fd-407e-9485-ded81a03427b","The effect of bubble size on lock-exchange density currents through bubble screens","O'Mahoney, Tom S.D. (Deltares); Oldenziel, G. (TU Delft Fluid Mechanics; Deltares); Van Der Ven, Pepijn (Deltares)","","2024","Bubble screens are used at sea locks to mitigate salt intrusion into inland water systems. In this paper the effectiveness of a bubble screen in delaying the mixing of salt and freshwater via lock exchange was studied. Laboratory-scale experiments investigating the flow field and mixing caused by a bubble screen are presented. The tests include both the homogeneous situation of freshwater on both sides of the screen and the inhomogeneous situation where there is an initial density difference across the screen, which leads to a density current after the lock gate is removed or opened. Optical measurement techniques were applied, giving spatially detailed flow velocities and densities. The parameters varied between tests are the airflow discharge and the bubble size. The results show that the bubble size in the screen had a significant effect with a screen with bubbles of 1-2 mm being more effective at generating a surface flow in the homogeneous case but less effective at keeping the fresh and salt sides separated in the inhomogeneous case, when compared with a screen of 4-6 mm bubbles. The point of maximum effectiveness for separating salt and fresh sides was also shown to be dependent on bubble size.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-15","","","Fluid Mechanics","","",""
"uuid:1475d5d6-0e4c-4354-a05e-552cb44ffa6d","http://resolver.tudelft.nl/uuid:1475d5d6-0e4c-4354-a05e-552cb44ffa6d","Hygrothermal ageing of dry gelatine adhesive films: Microstructure-property relationships","Mosleh, Yasmine (TU Delft Bio-based Structures & Materials); van Die, M. (TU Delft Structural Integrity & Composites); Gard, W.F. (TU Delft Bio-based Structures & Materials); Breebaart, Iskander (Rijksmuseum); van de Kuilen, J.W.G. (TU Delft Bio-based Structures & Materials; Technische Universität München); Van Duin, Paul (Rijksmuseum); Poulis, J.A. (TU Delft Adhesion Institute)","","2024","Gelatine adhesives, also known as animal glues, are collagen-based water-soluble biopolymers derived from vertebrate connective tissues. One of the various fields in which gelatine adhesives are widely used is the conservation of cultural heritage such as decorated furniture and panel paintings. It is observed that, with time, the failure in these objects often occurs along the adhesive bondlines. Given the moisture and temperature sensitivity of these adhesives, obtaining knowledge of their long-term behaviour, when exposed to climate variations, is pivotal. Here, the influence of hygrothermal ageing (exposure to a combination of elevated temperature and relative humidity (RH) cycling) on the microstructure and macroscopic properties of four different types of gelatine adhesives is investigated. These adhesives were selected from different animal origins namely bovine, rabbit, and fish with different Bloom strengths. It was observed that ageing cycles interfere with the most critical structural feature of protein chains namely triple helices. A clear decay in triple helix content at the micro-scale, determined by Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD) techniques, was observed which had implications on the macroscopic properties of these adhesives such as reduction of strain to failure and toughness (strain energy density to failure). The rate of decay in properties was revealed to be the highest in the adhesives with the lowest triple helix content. This study provides a scientific view of microstructure-property relationships in gelatinous adhesives as a function of environmental ageing, and stipulates the underlying mechanism of the degradation of mechanical properties as the loss of structural triple helices, regardless of the animal origin.","Hygrothermal ageing; Gelatine; Adhesive; Cultural heritage; Triple helix","en","journal article","","","","","","","","","","","Bio-based Structures & Materials","","",""
"uuid:4b25ed46-f288-40b4-83ff-6a34c1141116","http://resolver.tudelft.nl/uuid:4b25ed46-f288-40b4-83ff-6a34c1141116","Technology and Meditation:: Exploring the Challenges and Benefits of a Physical Device to Support Meditation Routine","Kermavnar, T. (TU Delft Design Aesthetics); Desmet, P.M.A. (TU Delft Human-Centered Design)","","2024","Existing studies of technology supporting meditation habit formation mainly focus on mobile applications which support users via reminders. A potentially more effective source of motivation could be contextual cues provided by meaningful objects in meaningful locations. This longitudinal mixed-methods 8-week study explored the effectiveness of such an object, Prana, in supporting forming meditation habits among seven novice meditators. First, the Meditation Intentions
Questionnaire-24 and the Determinants of Meditation Practice Inventory-Revised were administered. The self-report habit index (SrHI) was administered before and after the study. Prana recorded meditation session times, while daily diaries captured subjective experiences. At the end of the study, the system usability scale, the ten-item personality inventory, and the brief self-control scale were completed, followed by individual semi-structured interviews. We expected to find an increase in meditation frequency and temporal consistency, but the results failed to confirm this. Participants meditated for between 16% and 84% of the study. The frequency decreased with time for four, decreased with subsequent increase for two, and remained stable for one of them. Daily meditation experiences were positive, and the perceived difficulty to start meditating was low. No relevant correlation was found between the perceived difficulty in starting to meditate and meditation experience overall; the latter was only weakly associated with the likelihood of meditating the next day. While meditation became more habitual for six participants, positive scores on SrHI were rare. Despite the inconclusive results, this study provides valuable insights into challenges and benefits of using a meditation device, as well as potential methodological difficulties in studying habit formation with physical devices.","meditation; habit; routine; meditation technology; meditation lamp","en","journal article","","","","","","","","","","Human-Centered Design","Design Aesthetics","","",""
"uuid:fa63b1ff-5604-4826-adfe-3a4624dad27e","http://resolver.tudelft.nl/uuid:fa63b1ff-5604-4826-adfe-3a4624dad27e","Designing for a Flow: Navigating Temporalities in Housing Considerations in Low-Income and Hazard-Prone Caribbean Contexts","Kuś, A.M. (TU Delft Architectural Technology; Royal Netherlands Institute of Southeast Asian and Caribbean Studies); Mota, Nelson (TU Delft Space & Type); van Bueren, Ellen (TU Delft Management in the Built Environment); Carmona Báez, Antonio (University of St. Martin); Asselbergs, M.F. (TU Delft Architectural Technology)","","2024","The urgency of addressing housing challenges in low-income areas is increasing due to widening socio-economic inequalities and the worsening impact of natural disasters. Saint Martin, a small Caribbean island, is struggling to provide affordable housing amidst hurricanes, floods, and heat waves. As a result, there has been a rise in self-organized housing units, which are built incrementally and are susceptible to risks. The main challenge is to balance durability, functionality, and esthetic appeal over time. Inspired by St. Martin’s self-organized units, this article explores housing considerations in low-income, hazard-prone contexts by emphasizing their temporalities. Integrating insights from a formative study, including a literature review and ethnographic research, the paper draws on Stewart Brand’s “Layers of Change” and the concept of “Flow”. The study identifies layers within self-organized units corresponding to durability, functionality, and esthetic appeal. It delves into their connection with building activities over time, unveiling the temporalities of housing considerations. This exploration leads to the proposition of “Designing for a Flow” as a novel design approach. Offering practical insights within a concise framework, the study provides nuanced perspectives on mitigating housing challenges in low-income and hazard-prone contexts.","incremental housing; low-income housing; resilient design; climate change; extreme weather; layers of change; Stewart Brand; sustainability","en","journal article","","","","","","","","","","Management in the Built Environment","Architectural Technology","","",""
"uuid:8d8696e8-5213-469e-9ddc-2197a318a060","http://resolver.tudelft.nl/uuid:8d8696e8-5213-469e-9ddc-2197a318a060","River plastic transport affected by tidal dynamics","Schreyers, Louise J. (Wageningen University & Research); Van Emmerik, Tim H.M. (Wageningen University & Research); Bui, Thanh-Khiet L. (Vietnam National University); van Thi, Khoa L. (Wageningen University & Research; Hanoi University of Natural Resources and Environment, Hanoi); Vermeulen, Bart (Wageningen University & Research); Nguyen, Hong-Q. (Vietnam National University); Wallerstein, Nicholas (Wageningen University & Research); Uijlenhoet, R. (TU Delft Water Resources; Wageningen University & Research); van der Ploeg, Martine (Wageningen University & Research)","","2024","Plastic is an emerging pollutant, and the quantities in rivers and oceans are expected to increase. Rivers are assumed to transport land-based plastic into the ocean, and the fluvial and marine transport processes have been relatively well studied to date. However, the processes controlling the transport in tidal rivers and estuaries, the interface between fluvial and marine systems, remain largely unresolved. For this reason, current estimates of riverine plastic pollution and export into the ocean remain highly uncertain. Hydrodynamics in tidal rivers and estuaries are influenced by tides and freshwater discharge. As a consequence, flow velocity direction and magnitude can change diurnally. In turn, this impacts the transport dynamics of solutes and pollutants, including plastics. Plastic transport dynamics in tidal rivers and estuaries remain understudied, yet the available observations suggest that plastics can be retained here for long time periods, especially during periods of low net discharge. Additional factors such as riparian vegetation and riverbank characteristics, in combination with bi-directional flows and varying water levels, can lead to an even higher likelihood of long-term retention. Here, we provide a first observation-based estimate of net plastic transport on a daily timescale in tidal rivers. For this purpose, we developed a simple Eulerian approach using sub-hourly observations of plastic transport and discharge during full tidal cycles. We applied our method to the highly polluted Saigon River, Vietnam, throughout six full tidal cycles in May 2022. We show that the net plastic transport is about 20%-33% of the total plastic transport. We found that plastic transport and river discharge are positively and significantly correlated (Pearson's R2Combining double low line0.76). The net transport of plastic is higher than the net discharge (20%-33% and 16%, respectively), suggesting that plastic transport is governed by factors other than water flow. Such factors include wind, varying plastic concentrations in the water, and entrapment of plastics downstream of the measurement site. The plastic net transport rates alternate between positive (seaward) net transport and negative (landward) net transport as a result of the diurnal inequality in the tidal cycles. We found that soft and neutrally buoyant items had considerably lower net transport rates than rigid and highly buoyant items (10%-16% vs. 30%-38%), suggesting that transport dynamics strongly depend on item characteristics. Our results demonstrate the crucial role of tidal dynamics and bi-directional flows in plastic transport dynamics. With this paper we emphasize the importance of understanding fundamental transport dynamics in tidal rivers and estuaries to ultimately reduce the uncertainties of plastic emission estimates into the ocean.","","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:175cda3c-20cf-49ad-a335-323b5737d290","http://resolver.tudelft.nl/uuid:175cda3c-20cf-49ad-a335-323b5737d290","Profiling university students based on their acoustical and psychosocial preferences and characteristics of their home study places","Hamida, A.B. (TU Delft Environmental & Climate Design); Eijkelenboom, A.M. (TU Delft Environmental & Climate Design); Bluyssen, P.M. (TU Delft Environmental & Climate Design)","","2024","Understanding students' preferences of their study place, in particular acoustical and psychosocial preferences, is important to students' health and comfort. This study aimed to identify clusters of students with similar acoustical and psychosocial preferences, and to identify reasons for certain preferences of students in each cluster. A mixed-methods approach was applied, consisting of a questionnaire, which was completed by 451 bachelor students, and a field study conducted with 23 students from the same sample. The questionnaire data included among others acoustical and psychosocial preferences scores, while the field study data comprised interview transcripts, building checklists, and sound pressure level measurements. The questionnaire data were analysed using TwoStep cluster analysis to identify clusters of students based on their acoustical and psychosocial preferences. This produced five clusters of students that significantly differed in 14 variables, including preferences and perception of indoor environmental quality (e.g., noise from outside). Then, the field study data were analysed and categorised based on the five clusters of the students. The outcome explained the aspects associated with the acoustical preferences of students in each cluster. Building-related indicators such as the location of the building were found as an aspect that could affect the student's acoustical preferences. This study provides insight into the profiles of students based on their acoustical and psychosocial preferences, which are important for their health and comfort at their study places.","Acoustical preferences; TwoStep cluster analysis; Study places; Mixed methods; University students","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:936001c1-8cbd-4149-a4e3-41a177849046","http://resolver.tudelft.nl/uuid:936001c1-8cbd-4149-a4e3-41a177849046","The climatological renewable energy deviation index (credi)","Stoop, Laurens P. (Universiteit Utrecht; TenneT TSO B.V.); Van Der Wiel, Karin (Royal Netherlands Meteorological Institute (KNMI)); Zappa, William (TenneT TSO B.V.); Haverkamp, Arno (TenneT TSO B.V.); Feelders, Ad J. (Universiteit Utrecht); van den Broek, M.A. (TU Delft Energie and Industrie)","","2024","We propose an index to quantify and analyse the impact of climatological variability on the energy system at different timescales. We define the climatological renewable energy deviation index (credi) as the cumulative anomaly of a renewable resource with respect to its climate over a specific time period of interest. For this we introduce the smooth, yet physical, hourly rolling window climatology that captures the expected hourly to yearly behaviour of renewable resources. We analyse the presented index at decadal, annual and (sub-)seasonal timescales for a sample region and discuss scientific and practical implications. credi is meant as an analytical tool for researchers and stakeholders to help them quantify, understand, and explain, the impact of energy-meteorological variability on future energy system. Improved understanding translates to better assessments of how renewable resources, and the associated risks for energy security, may fare in current and future climatological settings. The practical use of the index is in resource planning. For example transmission system operators may be able to adjust short-term planning to reduce adequacy issues before they occur or combine the index with storyline event selection for improved assessments of climate change related risks.","","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:4161e45d-ecf4-4ff7-a56e-3e54874e57e8","http://resolver.tudelft.nl/uuid:4161e45d-ecf4-4ff7-a56e-3e54874e57e8","Studying the impact of lighting on the pedestrian route choice using Virtual Reality","van Beek, A.H.N. (TU Delft Transport and Planning); Feng, Y. (TU Delft Transport and Planning); Duives, D.C. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning)","","2024","Efficient crowd management is essential for optimizing the performance of pedestrian infrastructures, either in terms of crowd flow or pedestrian levels of safety and comfort. This study investigates the impact of one type of crowd management measure, namely lighting, on pedestrian behavior. Using Virtual Reality experiments, the impact of lighting, both the brightness level and the light color, on pedestrian route choice is studied. A virtual maze was designed, featuring 10 T-intersections, where the light conditions are varied at each T-intersection to study its impact on pedestrian route choice. Our study shows that pedestrian route choice is strongly influenced by the light color in a virtual environment. Pedestrians prefer to follow paths with green-colored lights and avoid paths with red-colored lights, irrespective of the light color on the other path. Moreover, pedestrians slightly prefer to use the path with a higher brightness level. Lastly, the results indicate that pedestrians do have a slight right-handed tendency on average, however, this effect cancels out almost completely when other guidance information is present in the scenario. Altogether, the findings suggest that lighting can impact pedestrian route choice behavior.
s) fitting results and rainfall characteristics of various events series length. Data from a full-scale grassed swale (Enschede, the Netherlands) were utilized as long-term rainfall event series length (95 rainfall events) on the fitting outcomes. Short-term rainfall event series were extracted from these long-term series and used as input in fitting into a multivariate nonlinear model between Ks and its influencing rainfall indicators (antecedent dry days, temperature, rainfall, rainfall duration, total rainfall, and seasonal factor (spring, summer, autumn, and winter, herein refer as 1, 2, 3, and 4). Comparison of short-term and long-term rainfall event series fitting results allowed to obtain a representative short-term series that leads to similar results with those using long-term series. A cluster analysis was conducted based on the fitting results of the representative rainfall event series with their rainfall event characteristics using average values of influencing rainfall indicators. The seasonal index (average value of seasonal factors) was found to be the most representative short rainfall event series indicator. Furthermore, a Bayesian network was proposed in the current study to predict if a given short-term rainfall event series is representative. It was validated by a data series (58 rainfall events) from another full-scale grassed swale located in Utrecht, the Netherlands. Results revealed that it is quite promising and useful to evaluate the representativeness of short-term rainfall event series used for long-term hydrological performance evaluation of grassed swales. Graphical Abstract: (Figure presented.).","Bayesian network; Grassed swale; Long-term hydrological performance; Rainfall event series; Representativeness; Saturated hydraulic conductivity","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-23","","","Hydraulic Structures and Flood Risk","","",""
"uuid:d38dab00-d96b-4657-8beb-ebb446649e68","http://resolver.tudelft.nl/uuid:d38dab00-d96b-4657-8beb-ebb446649e68","Measuring residual stresses in individual on-chip interconnects using synchrotron nanodiffraction","Zhang, Y. (TU Delft Electronic Components, Technology and Materials); Du, L. (TU Delft Electronic Components, Technology and Materials); Bäcke, Olof (Chalmers University of Technology); Kalbfleisch, Sebastian (MAX IV Laboratory); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Vollebregt, S. (TU Delft Electronic Components, Technology and Materials); Hörnqvist Colliander, Magnus (Chalmers University of Technology)","","2024","As the dimensions of interconnects in integrated circuits continue to shrink, an urgent need arises to understand the physical mechanism associated with electromigration. Using x-ray nanodiffraction, we analyzed the stresses in Blech-structured pure Cu lines subjected to different electromigration conditions. The results suggest that the measured residual stresses in the early stages of electromigration are related to relaxation of stresses caused by thermal expansion mismatch, while a developing current-induced stress leads to reductions in the residual stress after longer test times. These findings not only validate the feasibility of measuring stress in copper lines using nanodiffraction but also highlight the need for a further understanding, particularly through in situ electromigration experiments with x-ray nanodiffraction analysis.","","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:1f92feaf-60a1-4ac3-ad12-9cfc761303eb","http://resolver.tudelft.nl/uuid:1f92feaf-60a1-4ac3-ad12-9cfc761303eb","How aromatic dissolved organic matter differs in competitiveness against organic micropollutant adsorption","Wang, Q. (TU Delft Computational Design and Mechanics; Chinese Academy of Sciences); Lechtenfeld, Oliver J. (Helmholtz Centre for Environmental Research - UFZ); Rietveld, L.C. (TU Delft Sanitary Engineering); Schuster, Jonas (Hamburg University of Technology); Ernst, Mathias (Hamburg University of Technology); Hofman-Caris, Roberta (KWR Water Research Institute; Wageningen University & Research); Kaesler, Jan (Helmholtz Centre for Environmental Research - UFZ); Wang, Chunmiao (Chinese Academy of Sciences); Yang, Min (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Yu, Jianwei (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Zietzschmann, F.E. (TU Delft Sanitary Engineering; Berliner Wasserbetriebe)","","2024","Activated carbon is employed for the adsorption of organic micropollutants (OMPs) from water, typically present in concentrations ranging from ng L−1 to μg L−1. However, the efficacy of OMP removal is considerably deteriorated due to competitive adsorption from background dissolved organic matter (DOM), present at substantially higher concentrations in mg L−1. Interpreting the characteristics of competitive DOM is crucial in predicting OMP adsorption efficiencies across diverse natural waters. Molecular weight (MW), aromaticity, and polarity influence DOM competitiveness. Although the aromaticity-related metrics, such as UV254, of low MW DOM were proposed to correlate with DOM competitiveness, the method suffers from limitations in understanding the interplay of polarity and aromaticity in determining DOM competitiveness. Here, we elucidate the intricate influence of aromaticity and polarity in low MW DOM competition, spanning from a fraction level to a compound level, by employing direct sample injection liquid chromatography coupled with ultrahigh-resolution Fourier-transform ion cyclotron resonance mass spectrometry. Anion exchange resin pre-treatment eliminated 93% of UV254-active DOM, predominantly aromatic and polar DOM, and only minimally alleviated DOM competition. Molecular characterization revealed that nonpolar molecular formulas (constituting 26% PAC-adsorbable DOM) with medium aromaticity contributed more to the DOM competitiveness. Isomer-level analysis indicated that the competitiveness of highly aromatic LMW DOM compounds was strongly counterbalanced by increased polarity. Strong aromaticity-derived π-π interaction cannot facilitate the competitive adsorption of hydrophilic DOM compounds. Our results underscore the constraints of depending solely on aromaticity-based approaches as the exclusive interpretive measure for DOM competitiveness. In a broader context, this study demonstrates an effect-oriented DOM analysis, elucidating counterbalancing interactions of DOM molecular properties from fraction to compound level.","Activated carbon; Dissolved organic matter (DOM); Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS); Multi-component adsorption; Organic micropollutants","en","journal article","","","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:fac1766e-f6ef-43fb-a944-0f61f1b79cef","http://resolver.tudelft.nl/uuid:fac1766e-f6ef-43fb-a944-0f61f1b79cef","Damage Detection of Gantry Crane with a Moving Mass Using Artificial Neural Network","Safaei, Mohammad (University of Tabriz); Hejazian, Mahsa (University of Tabriz); Pedrammehr, Siamak (Tabriz Islamic Art University); Pakzad, Sajjad (Tabriz Islamic Art University); Ettefagh, Mir Mohammad (University of Tabriz); Fotouhi, M. (TU Delft Materials and Environment)","","2024","Gantry cranes play a pivotal role in various industrial applications, and their reliable operation is paramount. While routine inspections are standard practice, certain defects, particularly in less accessible components, remain challenging to detect early. In this study, first a finite element model is presented, and the damage is introduced using random changes in the stiffness of different parts of the structure. Contrary to the assumption of inherent reliability, undetected defects in crucial structural elements can lead to catastrophic failures. Then, the vibration equations of healthy and damaged models are analyzed to find the displacement, velocity, and acceleration of the different crane parts. The learning vector quantization neural network is used to train and detect the defects. The output is the location of the damage and the damage severity. Noisy data are then used to evaluate the network performance robustness. This research also addresses the limitations of traditional inspection methods, providing early detection and classification of defects in gantry cranes. The study’s relevance lies in the need for a comprehensive and efficient damage detection method, especially for components not easily accessible during routine inspections.","gantry crane; structural damage detection; finite element model; artificial neural network; learning vector quantization (LVQ)","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:63de6423-3d20-4816-9309-b0da1681af1e","http://resolver.tudelft.nl/uuid:63de6423-3d20-4816-9309-b0da1681af1e","The Development of a New Smart Evacuation Modeling Technique for Underground Mines Using Mathematical Programming","Meij, Richard (Student TU Delft); Soleymani Shishvan, M. (TU Delft Resource Engineering); Sattarvand, Javad (University of Nevada)","","2024","Navigating miners during an evacuation using smart evacuation technology can significantly decrease the evacuation time of an underground mine in case of emergency hazards. This paper presents a mathematical programming model to calculate the most efficient escape path for miners as a critical component of smart evacuation technology. In this model, the total evacuation distance of the crew is minimized and scenarios with blocked pathways and stamina categories for the miners are simulated. The findings revealed that all the tested scenarios were technically feasible. Using the feature that filters out blocked pathways has no downsides as safer routes are calculated and there is no penalty in the computation time. This paper also discusses the social and technical issues that must be resolved before the algorithm can be implemented as an actual escape solution.","smart evacuation; mathematical programming; hazards; underground mines","en","journal article","","","","","","","","","","","Resource Engineering","","",""
"uuid:ddb1a8c0-1d74-4815-b66f-7685d1cbde44","http://resolver.tudelft.nl/uuid:ddb1a8c0-1d74-4815-b66f-7685d1cbde44","A study of stone arch bridge’s flood reliability through a surrogate model approach","Baron, Edward A. (Universidade de Coimbra); Mendoza Cabanzo, Carlos (Universidade de Coimbra); Bento, Ana Margarida (Universidade do Porto; Centro Interdisciplinar de Investigação Marinha e Ambiental); Matos, Jose C. (Universidade de Coimbra); Calçada, Rui (Universidade do Porto); Gavin, Kenneth (TU Delft Geo-engineering)","","2024","Europe’s historic masonry arch bridges are culturally and economically significant, but their long-term safety must be ensured. Scour effects are the most common cause of collapse, so it is necessary to carry out structural assessments to mitigate the risk and prevent potential failures. In this study, a metamodel-based method was used to determine the probability of failure of an existing stone arch bridge in Portugal due to local and contraction scour on the abutments. Non-linear finite element analysis supported the calculation of the reliability index, which took into account the soil-structure interaction and the failure mechanism. The variables with the greatest influence on the load-carrying capacity of the structure were identified and a surrogate model was implemented. Fragility curves were then derived based on the surrogate model, using scour depth as a measure of intensity and load factor as an engineering requirement parameter. The results of the study indicate that the load capacity of the numerical model is compromised when the scour depth of 1.5 m reaches the base of the foundation. As a result, stability problems and settlements are observed in the model. At a depth of 2.5 m, the soil reaches its ultimate bearing capacity.","Bridge assessment; flood hazard; fragility curves; non-linear structural analysis; scour; soil-structure interaction; surrogate models; uncertainties","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-26","","","Geo-engineering","","",""
"uuid:e9f92bbb-0fbd-409f-be4f-86ad1b78f9cd","http://resolver.tudelft.nl/uuid:e9f92bbb-0fbd-409f-be4f-86ad1b78f9cd","Using problem-based exploratory training to improve pilot understanding of autopilot functions","van Leeuwen, J.K. (TU Delft Control & Simulation); Landman, H.M. (TU Delft BUS/TNO STAFF; TU Delft Control & Simulation); Groen, Eric L. (DIANA FEA); Mumaw, Randall J. (San José State University); Stroosma, O. (TU Delft Control & Simulation); van Paassen, M.M. (TU Delft Control & Simulation); Mulder, Max (TU Delft Control & Simulation)","","2024","Previous research indicated a need to improve pilot training with regard to understanding of autopilot logic and behavior, especially in non-routine situations. Therefore, we tested the effect of problem-based exploratory training on pilots’ understanding of autopilot functions. Using a moving-base flight simulator, general aviation pilots (n = 45) were trained to diagnose failures either without foreknowledge and guidance (exploratory group), without foreknowledge but with some guidance (exploratory-guidance group) or with foreknowledge and full guidance (control group). They subsequently performed six test scenarios in which their understanding of the effects of failures was tested by requiring them to deduce the failures and select autopilot modes that were still functioning. Those who received exploratory training with guidance were significantly more likely than the other groups to diagnose failures correctly. The exploratory training group also selected the most appropriate functioning autopilot modes significantly faster than the control group. The results suggest that exploratory training with an appropriate level of guidance is useful for gaining a practical understanding of autopilot logic and behavior. Exploratory training may help to improve transfer of training to operational practice, and prevent automation surprises and accidents.","Automation surprise; Human–automation interaction; Simulator training; Situation awareness; Transfer of training","en","journal article","","","","","","","","","","","Control & Simulation","","",""
"uuid:68dd0f90-d594-4239-b18d-43e3bf48cbde","http://resolver.tudelft.nl/uuid:68dd0f90-d594-4239-b18d-43e3bf48cbde","Sea-level rise induced change in exposure of low-lying coastal land: implications for coastal conservation strategies","Thiéblemont, Rémi (Bureau de Recherches Géologiques et Minières (BRGM)); le Cozannet, Gonéri (Bureau de Recherches Géologiques et Minières (BRGM)); Rohmer, Jérémy (Bureau de Recherches Géologiques et Minières (BRGM)); Privat, Adrien (Conservatoire du littoral); Guidez, Romain (Bureau de Recherches Géologiques et Minières (BRGM)); Negulescu, Caterina (Bureau de Recherches Géologiques et Minières (BRGM)); Philippenko, Xénia (Bureau de Recherches Géologiques et Minières (BRGM)); Luijendijk, Arjen (TU Delft Coastal Engineering; Deltares); Calkoen, F.R. (TU Delft Coastal Engineering; Deltares); Nicholls, Robert J. (University of East Anglia)","","2024","Coastal erosion and flooding are projected to increase during the 21st century due to sea-level rise (SLR). To prevent adverse impacts of unmanaged coastal development, national organizations can apply a land protection policy, which consists of acquiring coastal land to avoid further development. Yet, these reserved areas remain exposed to flooding and erosion enhanced by SLR. Here, we quantify the exposure of the coastal land heritage portfolio of the French Conservatoire du littoral (Cdl). We find that 30% (~40%) of the Cdl lands owned (projected to be owned) are located below the contemporary highest tide level. Nearly 10% additional surface exposure is projected by 2100 under the high greenhouse gas emissions scenario (SSP5-8.5) and 2150 for the moderate scenario (SSP2-4.5). The increase in exposure is largest along the West Mediterranean coast of France. We also find that Cdl land exposure increases more rapidly for SLR in the range of 0–1 m than for SLR in the range 2–4 m. Thus, near-future uncertainty on SLR has the largest impact on Cdl land exposure evolution and related land acquisition planning. Concerning erosion, we find that nearly 1% of Cdl land could be lost in 2100 if observed historical trends continue. Adding the SLR effect could lead to more than 3% land loss. Our study confirms previous findings that Cdl needs to consider land losses due to SLR in its land acquisition strategy and start acquiring land farther from the coast.","Climate change; Coastal conservation agency; Coastal hazards; Sea-level rise; Shoreline","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:019b6af3-3429-4c5a-97ce-b08665c4ac56","http://resolver.tudelft.nl/uuid:019b6af3-3429-4c5a-97ce-b08665c4ac56","Water-assisted generation of catalytic interface: The case of interfacial Pt-FeOx(OH)y sites active in preferential carbon monoxide oxidation","Sadykov, Ilia I. (Paul Scherrer Institut; ETH Zürich); Palagin, D. (TU Delft Numerical Analysis); Krumeich, Frank (ETH Zürich); Plokhikh, Igor V. (Paul Scherrer Institut); van Bokhoven, Jeroen A. (Paul Scherrer Institut; ETH Zürich); Nachtegaal, Maarten (Paul Scherrer Institut); Safonova, Olga V. (Paul Scherrer Institut)","","2024","The surface of supported heterogeneous catalysts often contains adsorbed water and hydroxyl groups even when water is not directly added to the reaction stream. Nonetheless, the reactivity of adsorbed water and hydroxyl groups is rarely considered. We demonstrate that water and hydroxyl groups can not only directly participate in the catalytic oxidation processes but are also able to generate and stabilize the catalytically active metal-oxide interface. We show that the reduction of Pt-Fe-supported catalysts with hydrogen in the presence of adsorbed water or steam allows for achieving one of the highest preferential carbon monoxide oxidation activities at ambient temperature. These conditions create active iron-associated hydroxyl groups next to platinum nanoparticles with enhanced reactivity towards carbon monoxide oxidation. Density functional theory calculations suggest that hydroxylation of oxidic iron species stabilizes the FeOx(OH)y/Pt interface, via strong metal-support interaction, which is confirmed by chemisorption measurements. Kinetic experiments, including those with 18O-labeled water, in combination with operando infrared spectroscopy, show that water and hydroxyl groups directly participate in preferential carbon monoxide oxidation. A quantitative correlation between the catalytic activity of Pt-FeOx(OH)y/γ-Al2O3 catalysts and the Fe2+ concentration, obtained using operando X-ray absorption spectroscopy, shows that the number of active Fe2+ sites and the carbon monoxide oxidation rate per active site can be significantly increased by water-assisted pretreatment with hydrogen. This work provides a new example of positive role of strong metal-support interaction for the design of more active catalysts.","Catalytic interface; Infrared spectroscopy; Operando; Preferential CO oxidation; Pt-Fe; Role of water; Structure-activity relationship; X-ray absorption spectroscopy","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:13c09c8b-40b2-4f3e-9f26-5c47ca308010","http://resolver.tudelft.nl/uuid:13c09c8b-40b2-4f3e-9f26-5c47ca308010","Asymmetric α-benzylation of cyclic ketones enabled by concurrent chemical aldol condensation and biocatalytic reduction","Liu, Yunting (Hebei University of Technology); Ma, Teng (Hebei University of Technology); Guo, Zhongxu (Hebei University of Technology); Zhou, Liya (Hebei University of Technology); Liu, Guanhua (Hebei University of Technology); He, Ying (Hebei University of Technology); Ma, Li (Hebei University of Technology); Gao, Jing (Hebei University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis)","","2024","Chemoenzymatic cascade catalysis has emerged as a revolutionary tool for streamlining traditional retrosynthetic disconnections, creating new possibilities for the asymmetric synthesis of valuable chiral compounds. Here we construct a one-pot concurrent chemoenzymatic cascade by integrating organobismuth-catalyzed aldol condensation with ene-reductase (ER)-catalyzed enantioselective reduction, enabling the formal asymmetric α-benzylation of cyclic ketones. To achieve this, we develop a pair of enantiocomplementary ERs capable of reducing α-arylidene cyclic ketones, lactams, and lactones. Our engineered mutants exhibit significantly higher activity, up to 37-fold, and broader substrate specificity compared to the parent enzyme. The key to success is due to the well-tuned hydride attack distance/angle and, more importantly, to the synergistic proton-delivery triade of Tyr28-Tyr69-Tyr169. Molecular docking and density functional theory (DFT) studies provide important insights into the bioreduction mechanisms. Furthermore, we demonstrate the synthetic utility of the best mutants in the asymmetric synthesis of several key chiral synthons.","","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:9821dbfc-62e6-4e64-bc9c-4348b08c43d2","http://resolver.tudelft.nl/uuid:9821dbfc-62e6-4e64-bc9c-4348b08c43d2","Design and modelling of a reversible shape memory alloy torsion hinge actuator","Liu, Q. (TU Delft Emerging Materials); Ghodrat, S. (TU Delft Emerging Materials); Jansen, K.M.B. (TU Delft Emerging Materials)","","2024","Conventional hinge actuators often face limitations including excessive weight, large size and unpleasant noise. Shape memory alloys (SMAs) offer a solution to address these issues due to their favorable characteristics, such as lightweight, high actuation force and small form factor. However, most existing SMA-based hinge actuators rely on the tension loading mode. Achieving an ideal actuation angle thereby necessitates the inclusion of long SMA wires, which inadvertently constrains the actuator size. Notably, the full potential of SMAs’ deformation capacities, encompassing torsion and bending, remains largely untapped and underutilized. In this research, a reversible torsion SMA hinge actuator is studied, which can reversibly open 60° during heating and cooling. The actuator weighs 2 g, and can produce actuation forces of up to 5 N. The mechanical performances of nitinol at different temperatures are measured. Based on the measurements, a model which can predict the opening and closing angle is proposed, with deviations of 13.5 ± 8.2 %. Gripper and butterfly demonstrators constructed by the hinge actuators are given as application examples. The actuators hold potential in many fields like soft robotics, aerospace and medical instruments.","Nitinol; Phenomenological model; Reversible hinge actuator; Shape memory alloy; Torsion deformation","en","journal article","","","","","","","","","","","Emerging Materials","","",""
"uuid:34f89481-a1ba-46b5-bbf5-09956c0aa540","http://resolver.tudelft.nl/uuid:34f89481-a1ba-46b5-bbf5-09956c0aa540","Automatic enhancement of vascular configuration for self-healing concrete through reinforcement learning approach","Wan, Z. (TU Delft Materials and Environment); Xu, Y. (TU Delft Materials and Environment); Chang, Z. (TU Delft Materials and Environment; Eindhoven University of Technology); Liang, M. (TU Delft Materials and Environment); Šavija, B. (TU Delft Materials and Environment)","","2024","Vascular self-healing concrete (SHC) has great potential to mitigate the environmental impact of the construction industry by increasing the durability of structures. Designing concrete with high initial mechanical properties by searching a specific arrangement of vascular structure is of great importance. Herein, an automatic optimization method is proposed to arrange vascular configuration for minimizing the adverse influence of vascular system through a reinforcement learning (RL) approach. A case study is carried out to optimize a concrete beam with 3 pores (representing a vascular network) positioned in the beam midspan within a design space of 40 possibilities. The optimization is performed by the interaction between RL agent and Abaqus simulation environment with the change of target properties as a reward signal. The results illustrates that the RL approach is able to automatically enhance the vascular arrangement of SHC given the fact that the 3-pore structures that have the maximum target mechanical property (i.e., peak load or fracture energy) are accessed for all of the independent runs. The RL optimization method is capable of identifying the structure with high fracture energy in the new optimization task for 4-pore concrete structure.","Concrete; Numerical simulation; Optimization; Reinforcement learning; Self-healing","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:34719c39-48f2-4edb-9e8d-1fc8af48996a","http://resolver.tudelft.nl/uuid:34719c39-48f2-4edb-9e8d-1fc8af48996a","Extracellular and intracellular effects of bioactive glass nanoparticles on osteogenic differentiation of bone marrow mesenchymal stem cells and bone regeneration in zebrafish osteoporosis model","Meng, Li (Nanjing Medical University); Zhao, Panpan (Nanjing Medical University); Jiang, Yucheng (Nanjing Medical University); You, Jiawen (Nanjing Medical University); Xu, Zhiyan (Friedrich-Alexander-Universität Erlangen-Nürnberg); Yu, K. (TU Delft BN/Marie-Eve Aubin-Tam Lab); Boccaccini, Aldo R. (Friedrich-Alexander-Universität Erlangen-Nürnberg); Ma, Junqing (Nanjing Medical University); Zheng, K. (Nanjing Medical University)","","2024","Bioactive glass nanoparticles (BGNs) are well-recognized multifunctional biomaterials for bone tissue regeneration due to their capability to stimulate various cellular processes through released biologically active ions. Understanding the correlation between BGN composition and cellular responses is key to developing clinically usable BGN-based medical devices. This study investigated the influence of CaO content of binary SiO2-CaO BGNs (CaO ranging from 0 to 10 mol%) on osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) and in vivo bone regeneration in zebrafish osteoporosis model. The results showed that BGNs could promote osteogenic differentiation of rBMSCs by indirectly releasing active ions or directly interacting with rBMSCs by internalization. In both situations, BGNs of a higher CaO content could promote the osteogenic differentiation of rBMSCs to a greater extent. The internalized BGNs could activate the transcription factors RUNX2 and OSX, leading to the expression of osteogenesis-related genes. The results in the zebrafish osteoporosis model indicated that the presence of BGNs of higher CaO contents could enhance bone regeneration and rescue dexamethasone-induced osteoporosis to a greater extent. These findings demonstrate that BGNs can stimulate osteogenic differentiation of rBMSCs by releasing active ions or internalization. A higher CaO content facilitates osteogenesis and bone regeneration of zebrafish as well as relieving dexamethasone-induced osteoporosis. The zebrafish osteoporosis model can be a potent tool for evaluating the in vivo bone regeneration effects of bioactive materials. Statement of significance: Bioactive glass nanoparticles (BGNs) are increasingly used as fillers of nanocomposites or as delivery platforms of active ions to regenerate bone tissue. Various studies have shown that BGNs can enhance osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) by releasing active ions. However, the correlation between BGN composition and cellular responses and in vivo bone regeneration effect has still not been well investigated. Establishment of a suitable in vivo animal model for investigating this correlation is also challenging. The present study reports the influence of CaO content in binary SiO2-CaO BGNs on osteogenic differentiation of BMSCs extracellularly and intracellularly. This study also demonstrates the suitability of zebrafish osteoporosis model to investigate in vivo bone regeneration effect of BGNs.","Bioactive glass; Bone regeneration; Cellular uptake; Osteoporosis; Zebrafish model","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-15","","","BN/Marie-Eve Aubin-Tam Lab","","",""
"uuid:e5bdaf21-e7ab-4694-abe2-e57f7412360a","http://resolver.tudelft.nl/uuid:e5bdaf21-e7ab-4694-abe2-e57f7412360a","Origin of fast charging in hard carbon anodes","Vasileiadis, A. (TU Delft RST/Storage of Electrochemical Energy); Zhou, Quan (Chinese Academy of Sciences; HiNa Battery Technology, Beijing); Lu, Yaxiang (Chinese Academy of Sciences); Li, Yu (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Ombrini, P. (TU Delft RST/Storage of Electrochemical Energy); Chen, Zhao (Chinese Academy of Sciences; University of Chinese Academy of Sciences); van der Jagt, R. (TU Delft RST/Storage of Electrochemical Energy); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2024","Transport electrification and grid storage hinge largely on fast-charging capabilities of Li- and Na-ion batteries, but anodes such as graphite with plating issues drive the scientific focus towards anodes with slopped storage potentials. Here we report fast charging of ampere-hour-level full Na-ion batteries within about 9 minutes for continuous 3,000 cycles based on hard carbon anodes. These anodes, in addition to displaying a sloped storage voltage, provide capacity at a nearly constant voltage just above the plating potential, without observing Na-metal plating under high areal capacity. Comparing the electrochemical behaviour of Li and Na in hard carbon through experimental and computational techniques, a unified storage mechanism relying on the dimensions of wedge nanopores and drawing parallels with underpotential deposition for metals is brought forward, providing a rational guide for achieving fast storage in hard carbon anodes.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-03","","","RST/Storage of Electrochemical Energy","","",""
"uuid:7df62dc3-ecba-4176-a9c1-18a40b82debe","http://resolver.tudelft.nl/uuid:7df62dc3-ecba-4176-a9c1-18a40b82debe","Solving inverse scattering problems via reduced-order model embedding procedures","Zimmerling, J.T. (TU Delft Signal Processing Systems; Uppsala University); Druskin, Vladimir (Worcester Polytechnic Institute); Guddati, Murthy (University of North Carolina); Cherkaev, Elena (University of Utah, College Of Science); Remis, R.F. (TU Delft Tera-Hertz Sensing)","","2024","We present a reduced-order model (ROM) methodology for inverse scattering problems in which the ROMs are data-driven, i.e. they are constructed directly from data gathered by sensors. Moreover, the entries of the ROM contain localised information about the coefficients of the wave equation. We solve the inverse problem by embedding the ROM in physical space. Such an approach is also followed in the theory of ‘optimal grids,’ where the ROMs are interpreted as two-point finite-difference discretisations of an underlying set of equations of a first-order continuous system on this special grid. Here, we extend this line of work to wave equations and introduce a new embedding technique, which we call Krein embedding, since it is inspired by Krein’s seminal work on vibrations of a string. In this embedding approach, an adaptive grid and a set of medium parameters can be directly extracted from a ROM and we show that several limitations of optimal grid embeddings can be avoided. Furthermore, we show how Krein embedding is connected to classical optimal grid embedding and that convergence results for optimal grids can be extended to this novel embedding approach. Finally, we also briefly discuss Krein embedding for open domains, that is, semi-infinite domains that extend to infinity in one direction.","embedding; inverse scattering; optimal grids; reduced-order models","en","journal article","","","","","","","","","","","Signal Processing Systems","","",""
"uuid:44c80a1d-ad64-4c88-992c-e6ec02cf71d4","http://resolver.tudelft.nl/uuid:44c80a1d-ad64-4c88-992c-e6ec02cf71d4","On the necessity of new hydrophobic treatment after repointing of water repellent masonry","Nijland, Timo G. (TNO); Lubelli, B. (TU Delft Heritage & Architecture); van Zundert, Kim (TNO); van Hunen, Michiel (Cultural Heritage Agency of the Netherlands)","","2024","The impregnation of the exterior surface of a masonry wall with a water repellent is a common intervention in (historic) building renovation and maintenance. Such treatments, whilst degrading at the surface with time under influence of ultra violet light, remain effective below the surface several decades after their application. During renovation works of masonry previously treated with a water repellent, the question arises whether it is necessary to repeat the hydrophobic treatment of the entire masonry after repointing. Opposing opinions exist with this regard, but no research clearly supporting one or the other. This research investigates for the first time the effect of hydrophobic treatment when applied on previously treated and repointed masonry walls. Small masonry walls were subjected to rain periods in the laboratory and their water uptake and drying behaviour were studied. Moreover, this laboratory research was followed by 30 months of outdoor exposition of the masonry specimens. The following cases were considered: (1) wall treated with water repellent, (2) wall treated with water repellent, followed by repointing but without new water repellent treatment, (3) wall treated with water repellent, followed by repointing and retreatment. This was done for three different types of pointing mortar: ordinary Portland cement and natural hydraulic lime with standard sand, and natural hydraulic lime with sand with one grain size. The results show that, after prolonged rain periods, the water uptake by repointed but not retreated masonry is comparable to that of untreated, non-hydrophobic masonry, whereas drying is considerably slower. This leads to a high saturation degree in repointed but not retreated masonry, which, in turn, increases the risk of damage to the masonry by e.g. frost. Therefore, retreating repointed hydrophobic masonry should definitively be considered.","Absorption behavior; Drying behaviour; Hydrophobic treatment; Masonry; Pointing mortar; Re-pointing","en","journal article","","","","","","","","","","","Heritage & Architecture","","",""
"uuid:a0726188-1df7-4115-a43f-84d87d6167aa","http://resolver.tudelft.nl/uuid:a0726188-1df7-4115-a43f-84d87d6167aa","Electrodeposited Sn-Cu-Ni alloys as lead-free solders on copper substrate using deep eutectic solvents: The influence of electrodeposition mode on the morphology, composition and corrosion behaviour","State, Sabrina Patricia (Politehnica University of Bucharest); Costovici, Stefania (Politehnica University of Bucharest); Mousavi, M. (TU Delft Team Yaiza Gonzalez Garcia); Gonzalez Garcia, Y. (TU Delft Team Yaiza Gonzalez Garcia); Zanella, Caterina (Jönköping University); Cojocaru, Anca (Politehnica University of Bucharest); Anicai, Liana (Politehnica University of Bucharest); Visan, Teodor (Politehnica University of Bucharest); Enachescu, Marius (Politehnica University of Bucharest)","","2024","In this work we present the pulsed current (PC) electrodeposition of Sn-Cu-Ni alloy as lead-free solder candidate, from choline chloride – ethylene glycol eutectic mixtures (1:2 molar ratio) onto copper metallic substrates. Electrolytes containing Sn2+, Cu2+ and Ni2+ salts in the selected deep eutectic solvent have been considered. The effect of the applied frequency of PC on the morphology, composition and melting point of the alloy is discussed and compared to the ones obtained using direct current (DC) plating mode. A refinement of the grain size and lower melting temperature of the alloy were noticed when pulsed current was applied. A comparative analysis of the electrochemical corrosion behaviour at macro- and micro- scale has been performed in 0.5 M and 0.1 M NaCl solutions involving potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode (SVET) techniques. Furthermore, an analysis after 96 h of exposure to salt mist test simulating a corrosive attack in harsh environment is presented, too. The obtained results showed enhanced corrosion resistance of the ternary alloys electrodeposited under PC conditions (the best for 1.67 Hz frequency) as compared to those using DC. Additionally, Raman spectroscopy evidenced the presence of tin oxi/hydroxy chloride and tin oxides as surface corrosion products. A corrosion mechanism has been proposed.","Corrosion behaviour; Deep eutectic solvents; Electrodeposition; Sn-Cu-Ni ternary alloy; SVET","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-21","","","Team Yaiza Gonzalez Garcia","","",""
"uuid:1eb6c85b-454b-4052-90f9-1f85b4fb8845","http://resolver.tudelft.nl/uuid:1eb6c85b-454b-4052-90f9-1f85b4fb8845","A new sedimentary and biostratigraphic framework for the Callovian-Oxfordian transition on the Atlantic margin of Morocco","Duval-Arnould, Aude (The University of Manchester); Bulot, Luc (The University of Manchester); Masrour, Moussa (Ibn Zohr University); Simmons, Mike (Neftex-Halliburton); Bonnot, Alain (Université de Bourgogne); Charton, R.J.G. (TU Delft Applied Geology); Redfern, Jonathan (The University of Manchester); Schröder, Stefan (The University of Manchester)","","2024","A major global marine transgression occurred during the Callovian to Early Kimmeridgian, which was interrupted locally by a hiatus during the Late Callovian to Early Oxfordian. The transgression may have been a major driver for extensive coral buildup development in the Oxfordian. The depositional hiatus may be related to a combination of eustasy, local tectonic activity and hinterland movements, highlighting the potential influence of tectonism on sedimentary evolution in sedimentary basins. Whilst a regional Late Callovian-Early Oxfordian hiatus has been recorded extensively in the Tethys realm, this study has improved the biostratigraphic and sedimentary record from Morocco, and for the first time documents the Late Callovian-Early Oxfordian depositional hiatus in the Atlantic realm. Detailed sedimentary facies analysis of Callovian to Oxfordian carbonates and siliciclastics (Ouanamane Formation) demonstrates a major transgression from continental and coastal sediments, through oolitic mid-inner ramp deposits, brachiopod-rich middle ramp deposits, and ultimately to outer ramp marls, sharply overlain by Middle Oxfordian coral buildups across the basin. Repeated hard- and firmgrounds and bioturbated bed tops highlight transgressive surfaces traceable basinwide, which suggests low sedimentation rates in the upper Ouanamane Formation. Localized siliciclastic input is evidence for episodes of erosion in the same interval. Collection of new fossil specimens (ammonites, brachiopods, echinoderms, foraminifera) and revision of existing fossil material suggest this interval corresponds to a hiatus or condensed section in the Callovian-Oxfordian transition. The uppermost part of the Ouanamane Formation is of early Middle Oxfordian age and is directly overlain by Middle Oxfordian coral buildups. Onset of buildup construction is considered synchronous based on the new biostratigraphic data. Observations in Moroco compare with the sedimentary evolution around the Tethys, and in particular with the Arabian Plate. The Callovian-Oxfordian depositional hiatus corresponds to eustatic sea level changes, which were possibly driven by global cooling, and was likely overprinted by local tectonics.","Biostratigraphy; Callovian-oxfordian transgression; Carbonate ramp; Coral buildup; Depositional hiatus","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:00b696c3-aa93-46b6-b1a7-ea27ee13c13e","http://resolver.tudelft.nl/uuid:00b696c3-aa93-46b6-b1a7-ea27ee13c13e","Distinct spatiotemporal dynamics of CD8+ T cell-derived cytokines in the tumor microenvironment","Hoekstra, Mirjam E. (Netherlands Cancer Institute); Slagter, Maarten (Netherlands Cancer Institute); Urbanus, Jos (Netherlands Cancer Institute); Toebes, Mireille (Netherlands Cancer Institute); Slingerland, Nadine (Netherlands Cancer Institute); de Rink, Iris (Netherlands Cancer Institute); Kluin, Roelof J.C. (Netherlands Cancer Institute); Nieuwland, Marja (Netherlands Cancer Institute); Wessels, L.F.A. (TU Delft Pattern Recognition and Bioinformatics; Netherlands Cancer Institute)","","2024","Cells in the tumor microenvironment (TME) influence each other through secretion and sensing of soluble mediators, such as cytokines and chemokines. While signaling of interferon γ (IFNγ) and tumor necrosis factor α (TNFα) is integral to anti-tumor immune responses, our understanding of the spatiotemporal behavior of these cytokines is limited. Here, we describe a single cell transcriptome-based approach to infer which signal(s) an individual cell has received. We demonstrate that, contrary to expectations, CD8+ T cell-derived IFNγ is the dominant modifier of the TME relative to TNFα. Furthermore, we demonstrate that cell pools that show abundant IFNγ sensing are characterized by decreased expression of transforming growth factor β (TGFβ)-induced genes, consistent with IFNγ-mediated TME remodeling. Collectively, these data provide evidence that CD8+ T cell-secreted cytokines should be categorized into local and global tissue modifiers, and describe a broadly applicable approach to dissect cytokine and chemokine modulation of the TME.","cytokine; IFN-gamma; single cell RNA-seq; T cell; TNF-alpha; tumor microenvironment","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:dfb53726-d466-4f7a-b6a2-f5565cc200d9","http://resolver.tudelft.nl/uuid:dfb53726-d466-4f7a-b6a2-f5565cc200d9","Cerebrospinal fluid proteomics in patients with Alzheimer’s disease reveals five molecular subtypes with distinct genetic risk profiles","Tijms, Betty M. (Vrije Universiteit Amsterdam; Amsterdam Neuroscience); Vromen, Ellen M. (Vrije Universiteit Amsterdam; Amsterdam Neuroscience); Mjaavatten, Olav (University of Bergen and Bjerknes Centre for Climate Research); Holstege, Henne (Alzheimer Center Amsterdam; Vrije Universiteit Amsterdam); Reus, Lianne M. (Vrije Universiteit Amsterdam; Amsterdam Neuroscience; University of California); van der Lee, Sven (Alzheimer Center Amsterdam; Vrije Universiteit Amsterdam); Wesenhagen, Kirsten E.J. (Vrije Universiteit Amsterdam; Amsterdam Neuroscience); Lorenzini, Luigi (Vrije Universiteit Amsterdam; Amsterdam Neuroscience); Tesi, N. (TU Delft Pattern Recognition and Bioinformatics; Vrije Universiteit Amsterdam)","","2024","Alzheimer’s disease (AD) is heterogenous at the molecular level. Understanding this heterogeneity is critical for AD drug development. Here we define AD molecular subtypes using mass spectrometry proteomics in cerebrospinal fluid, based on 1,058 proteins, with different levels in individuals with AD (n = 419) compared to controls (n = 187). These AD subtypes had alterations in protein levels that were associated with distinct molecular processes: subtype 1 was characterized by proteins related to neuronal hyperplasticity; subtype 2 by innate immune activation; subtype 3 by RNA dysregulation; subtype 4 by choroid plexus dysfunction; and subtype 5 by blood–brain barrier impairment. Each subtype was related to specific AD genetic risk variants, for example, subtype 1 was enriched with TREM2 R47H. Subtypes also differed in clinical outcomes, survival times and anatomical patterns of brain atrophy. These results indicate molecular heterogeneity in AD and highlight the need for personalized medicine.","","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:35c1966b-74d4-40c2-b43d-05daf70246b5","http://resolver.tudelft.nl/uuid:35c1966b-74d4-40c2-b43d-05daf70246b5","Estimating geodynamic model parameters from geodetic observations using a particle method","Marsman, C. P. (Universiteit Utrecht); Vossepoel, F.C. (TU Delft Reservoir Engineering); Van Dinther, Y. (Universiteit Utrecht); Govers, R. (Universiteit Utrecht)","","2024","Bayesian-based data assimilation methods integrate observational data into geophysical forward models to obtain the temporal evolution of an improved state vector, including its uncertainties. We explore the potential of a variant, a particle method, to estimate mechanical parameters of the overriding plate during the interseismic period. Here we assimilate vertical surface displacements into an elementary flexural model to estimate the elastic thickness of the overriding plate, and the locations and magnitudes of line loads acting on the overriding plate to produce flexure. Assimilation of synthetic observations sampled from a different forward model than is used in the particle method, reveal that synthetic seafloor data within 150 km from the trench are required to properly constrain parameters for long wavelength solutions of the upper plate (i.e. wavelength ∼500 km). Assimilation of synthetic observations sampled from the same flexural model used in the particle method shows remarkable convergence towards the true parameters with synthetic on-land data only for short to intermediate wavelength solutions (i.e. wavelengths between ∼100 and 300 km). In real-data assimilation experiments we assign representation errors due to discrepancies between our incorrect or incomplete physical model and the data. When assimilating continental data prior to the 2011 Mw Tohoku-Oki earthquake (1997-2000), an unrealistically low effective elastic plate thickness for Tohoku of ∼5-7 km is estimated. Our synthetic experiments suggest that improvements to the physical forward model, such as the inclusion of a slab, a megathrust interface and viscoelasticity of the mantle, including accurate seafloor data, and additional geodetic observations, may refine our estimates of the effective elastic plate thickness. Overall, we demonstrate the potential of using the particle method to constrain geodynamic parameters by providing constraints on parameters and corresponding uncertainty values. Using the particle method, we provide insights into the data network sensitivity and identify parameter trade-offs.","Inverse theory; Lithospheric flexure; Probabilistic forecasting; Statistical methods; Subduction zone processes; Time-series analysis","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:bee8d20f-da49-44fc-8295-2996e2962eb1","http://resolver.tudelft.nl/uuid:bee8d20f-da49-44fc-8295-2996e2962eb1","Economic assessment of nature-based solutions to reduce flood risk and enhance co-benefits","Ruangpan, L. (TU Delft BT/Environmental Biotechnology; IHE Delft Institute for Water Education); Vojinovic, Zoran (IHE Delft Institute for Water Education; University of Belgrade; University of Exeter); Plavšić, Jasna (University of Belgrade); Curran, Alex (HKV Lijn in Water); Rosic, Nikola (University of Belgrade); Pudar, Ranko (Pudar Mitigation Consulting); Savic, Dragan (University of Exeter; KWR Water Research Institute); Brdjanovic, Damir (TU Delft BT/Environmental Biotechnology; IHE Delft Institute for Water Education)","","2024","Flooding is expected to increase due to climate change, urbanisation, and land use change. To address this issue, Nature-Based Solutions (NBSs) are often adopted as innovative and sustainable flood risk management methods. Besides the flood risk reduction benefits, NBSs offer co-benefits for the environment and society. However, these co-benefits are rarely considered in flood risk management due to the inherent complexities of incorporating them into economic assessments. This research addresses this gap by developing a comprehensive methodology that integrates the monetary analysis of co-benefits with flood risk reduction in economic assessments. In doing so, it aspires to provide a more holistic view of the impact of NBS in flood risk management. The assessment employs a framework based on life-cycle cost-benefit analysis, offering a systematic and transparent assessment of both costs and benefits over time supported by key indicators like net present value and benefit cost ratio. The methodology has been applied to the Tamnava basin in Serbia, where significant flooding occurred in 2014 and 2020. The methodology offers valuable insights for practitioners, researchers, and planners seeking to assess the co-benefits of NBS and integrate them into economic assessments. The results show that when considering flood risk reduction alone, all considered measures have higher costs than the benefits derived from avoiding flood damage. However, when incorporating co-benefits, several NBS have a net positive economic impact, including afforestation/reforestation and retention ponds with cost-benefit ratios of 3.5 and 5.6 respectively. This suggests that incorporating co-benefits into economic assessments can significantly increase the overall economic efficiency and viability of NBS.","Adaptation measures; Co-benefits; Cost-benefits analysis; Life cycle assessment; Monetary; NBS","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:0ed7fb06-8e1c-4c52-b809-d32b0191c1da","http://resolver.tudelft.nl/uuid:0ed7fb06-8e1c-4c52-b809-d32b0191c1da","On the impact of decision rule assumptions in experimental designs on preference recovery: An application to climate change adaptation measures","van Cranenburgh, S. (TU Delft Transport and Logistics); Meyerhoff, Jürgen (Hochschule für Wirtschaft und Recht Berlin); Rehdanz, Katrin (Christian-Albrechts-Universität zu Kiel); Wunsch, Andrea (Kiel Institute for the World Economy)","","2024","Efficient experimental designs aim to maximise the information obtained from stated choice data to estimate discrete choice models' parameters statistically efficiently. Almost without exception efficient experimental designs assume that decision-makers use a Random Utility Maximisation (RUM) decision rule. When using such designs, researchers (implicitly) assume that the decision rule used to generate the design has no impact on respondents' choice behaviour. This study investigates whether the decision rule assumption underlying an experimental design affects respondents' choice behaviour. We use four stated choice experiments on coastal adaptation to climate change: Two are based on experimental designs optimised for utility maximisation and two are based on experimental designs optimised for a mixture of RUM and Random Regret Minimisation (RRM). Generally, we find that respondents place value on adaptation measures (e.g., dykes and beach nourishments). We evaluate the models' fits and investigate whether some choice tasks particularly invoke RUM or RRM decision rules. For the latter, we develop a new sampling-based approach that avoids the confounding between preference and decision rule heterogeneity. We find no evidence that RUM-optimised designs invoke RUM-consistent choice behaviour. However, we find a relationship between some of the attributes and decision rules, and compelling evidence that some choice tasks invoke RUM consistent behaviour while others invoke RRM consistent behaviour. This implies that respondents’ choice behaviour and choice modelling outcomes are not exogenous to the choice tasks, which can be particularly critical when information on preferences is used to inform actual decision-making on a sensitive issue of common interest as climate change.","Climate change; Coastal adaptation; Decision rules; Experimental design theory; Random regret minimisation","en","journal article","","","","","","","","","","","Transport and Logistics","","",""
"uuid:b662a072-1c86-47ad-aa5a-87f1d11e5b2c","http://resolver.tudelft.nl/uuid:b662a072-1c86-47ad-aa5a-87f1d11e5b2c","3D macro-element for innovative plug-and-play joints","Miculaş, Cristian V. (Universidade de Coimbra); Costa, Ricardo J. (Universidade de Coimbra); da Silva, Luis Simões (Universidade de Coimbra); Simões, Rui (Universidade de Coimbra); Craveiro, Helder (Universidade de Coimbra); Tankova, T. (TU Delft Steel & Composite Structures)","","2024","This paper presents the development, implementation, and validation of a macro-element suitable for the linear analysis of innovative 3D plug-and-play joints between tubular columns and lightweight steel truss-girders. The macro-element is based on the component method, accounts for the three-dimensional interaction between the tube faces, and its components have a clear physical meaning. Simplified procedures are developed for the closed-form computation of the stiffness matrix of the macro-element based on the geometric and mechanical properties of the nodal zone. This facilitates practical application in everyday design scenarios. Furthermore, the macro-element's architecture is implemented in the framework of OpenSees as a standalone beam-to-column joint finite element. Validation of the conceptual design is accomplished through parametric studies, comparing its performance with models generated in higher-order finite element commercial software, Abaqus. This research offers a valuable resource for the linear analysis and design of innovative 3D plug-and-play joint connections in structural engineering, enhancing efficiency and reliability in construction practices.","Innovative plug-and-play joints; Lightweight steel frames; Macro-element; OpenSees; Tubular columns","en","journal article","","","","","","","","","","","Steel & Composite Structures","","",""
"uuid:1a8445b5-3f95-4b2f-b53d-01e3df9c7349","http://resolver.tudelft.nl/uuid:1a8445b5-3f95-4b2f-b53d-01e3df9c7349","Mass-change And Geosciences International Constellation (MAGIC) expected impact on science and applications","Daras, I. (European Space Agency (ESA)); March, G. (RHEA for European Space Agency); Pail, R. (Technische Universität München); Hughes, C. W. (University of Liverpool; National Oceanography Center); Braitenberg, C. (University of Trieste); Guntner, A. (University of Potsdam; Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences); Eicker, A. (HafenCity University Hamburg); Wouters, B. (TU Delft Physical and Space Geodesy); Heller-Kaikov, B. (Technische Universität München)","","2024","The joint ESA/NASA Mass-change And Geosciences International Constellation (MAGIC) has the objective to extend time-series from previous gravity missions, including an improvement of accuracy and spatio-temporal resolution. The long-term monitoring of Earth’s gravity field carries information on mass change induced by water cycle, climate change and mass transport processes between atmosphere, cryosphere, oceans and solid Earth. MAGIC will be composed of two satellite pairs flying in different orbit planes. The NASA/DLR-led first pair (P1) is expected to be in a near-polar orbit around 500 km of altitude; while the second ESA-led pair (P2) is expected to be in an inclined orbit of 65◦–70◦ at approximately 400 km altitude. The ESA-led pair P2 Next Generation Gravity Mission shall be launched after P1 in a staggered manner to form the MAGIC constellation. The addition of an inclined pair shall lead to reduction of temporal aliasing effects and consequently of reliance on de-aliasing models and post-processing. The main novelty of the MAGIC constellation is the delivery of mass-change products at higher spatial resolution, temporal (i.e. subweekly) resolution, shorter latency and higher accuracy than the Gravity Recovery and Climate Experiment (GRACE) and Gravity Recovery and Climate Experiment Follow-On (GRACE-FO). This will pave the way to new science applications and operational services. In this paper, an overview of various fields of science and service applications for hydrology, cryosphere, oceanography, solid Earth, climate change and geodesy is provided. These thematic fields and newly enabled applications and services were analysed in the frame of the initial ESA Science Support activities for MAGIC. The analyses of MAGIC scenarios for different application areas in the field of geosciences confirmed that the double-pair configuration will significantly enlarge the number of observable mass-change phenomena by resolving smaller spatial scales with an uncertainty that satisfies evolved user requirements expressed by international bodies such as IUGG. The required uncertainty levels of dedicated thematic fields met by MAGIC unfiltered Level-2 products will benefit hydrological applications by recovering more than 90 per cent of the major river basins worldwide at 260 km spatial resolution, cryosphere applications by enabling mass change signal separation in the interior of Greenland from those in the coastal zones and by resolving small-scale mass variability in challenging regions such as the Antarctic Peninsula, oceanography applications by monitoring meridional overturning circulation changes on timescales of years and decades, climate applications by detecting amplitude and phase changes of Terrestrial Water Storage after 30 yr in 64 and 56 per cent of the global land areas and solid Earth applications by lowering the Earthquake detection threshold from magnitude 8.8 to magnitude 7.4 with spatial resolution increased to 333 km.","Earthquake dynamics; Glaciology; Global change from geodesy; Hydrology; Satellite gravity; Time variable gravity","en","journal article","","","","","","","","","","","Physical and Space Geodesy","","",""
"uuid:16b3382f-fbfd-4d0a-a848-4bfcebb8840d","http://resolver.tudelft.nl/uuid:16b3382f-fbfd-4d0a-a848-4bfcebb8840d","Review of the state of art of Li-based inhibitors and coating technology for the corrosion protection of aluminium alloys","Li, Z. (TU Delft Team Arjan Mol); Visser, Peter (Akzo Nobel); Hughes, Anthony E. (CSIRO Mineral Resources); Homborg, A.M. (TU Delft Team Arjan Mol; Netherlands Defence Academy); Gonzalez Garcia, Y. (TU Delft Team Yaiza Gonzalez Garcia); Mol, J.M.C. (TU Delft Team Arjan Mol)","","2024","The quest for novel alternatives to hexavalent-chromium-based corrosion inhibitors is of utmost significance and urgency. Strict international health and safety regulations, due to growing concerns regarding the impact of hexavalent chromium on human health and the environment, have pushed the commercial introduction of many alternative inhibitor types, but the implementation of alternative active protective primers for structural parts in the aerospace industry is still pending. This endeavour has proven to be remarkably challenging, as the potential replacement coating types must meet numerous functional requirements encompassing cost-effectiveness and exceptional corrosion protection for intrinsically corrosion susceptible aerospace aluminium alloys. In recent years, considerable attention has been drawn to lithium salts as environmentally friendly corrosion inhibitors forming the basis for a novel active protective coating technology. The involvement of lithium ions has been shown to play a pivotal role in the conversion process of aluminium alloy surfaces by stabilizing the reaction products, thereby facilitating the gradual development of a protective layer with a multi-layered configuration, which exhibits considerable variability in morphology, depending on local chemical and electrochemical conditions. The versatility of the lithium-based corrosion protection extends to their application as corrosion inhibiting pigments in organic coatings or as a pre-treatment, directly forming conversion layers, thereby enhancing their practical implementation. However, previous chromate replacement reviews only introduced the promising outcomes provided by the lithium technology, omitting key details of its development and formation mechanism. This paper critically reviews and summarizes the studies conducted to date on lithium-based inhibitor technologies for the corrosion protection of aluminium alloys as well as topics to be investigated in the future.","Aluminium alloy; Coating technology; Corrosion protection; lithium inhibitor","en","journal article","","","","","","","","","","","Team Arjan Mol","","",""
"uuid:61868d82-e498-4bb0-8352-616415580c4f","http://resolver.tudelft.nl/uuid:61868d82-e498-4bb0-8352-616415580c4f","Unravelling microstructure-electroactivity relationships in free-standing polycrystalline boron-doped diamond: A mapping study","Liu, Z. (TU Delft Micro and Nano Engineering); Baluchová, S. (TU Delft Micro and Nano Engineering); Li, Z. (TU Delft Team Arjan Mol); Gonzalez Garcia, Y. (TU Delft Team Yaiza Gonzalez Garcia); Hall, Clive E. (Mintres B.V.); Buijnsters, J.G. (TU Delft Micro and Nano Engineering)","","2024","In this work, four different techniques were concurrently applied to study the interplay between local electroactivity and electrode surface characteristics of free-standing, polycrystalline boron-doped diamond (BDD). Scanning electron microscopy, electron back-scatter diffraction, Raman mapping and scanning electrochemical microscopy were used to probe the electrode morphology, grain orientation and boundaries, composition, and local electrochemical activity, respectively. Both nucleation and growth BDD surfaces together with the cross-section area were carefully investigated for the first time in a single study using the combination of all four techniques. This enabled us to obtain significant insights into the highly heterogeneous nature of the polycrystalline BDD material. Notably, boron dopants were confirmed to be non-uniformly distributed over the BDD material, which is characterized by a distinct columnar structure and composition of grains of various orientations. Particularly, the highest electrochemical activity was recorded on the highest doped (111) crystal orientation. In contrast, the averagely boron-doped (100)-oriented facet showed non-conductive nature. This highlights that the local electrochemical activity of the BDD surface is strongly grain-dependent and the most significant factors governing the obtained responses are crystallographic orientation and boron doping. Moreover, increased boron and sp2 carbon content in the boundary regions was recognized by Raman mapping. However, such localized enrichment in impurities did not translate into enhanced electrochemical activity, which implies that boron atoms at the inter-grain areas are predominantly inactive. Finally, it is crucial to consider all characteristics of the polycrystalline BDD including crystal orientation, which is particularly relevant if micro- and nanoscale probing is intended.","Boron-doped diamond (BDD); Electron backscatter diffraction; Grain boundaries; Raman mapping; Scanning electrochemical microscopy (SECM)","en","journal article","","","","","","","","","","","Micro and Nano Engineering","","",""
"uuid:46b9457b-7427-42cd-a595-0a2c7ced3c63","http://resolver.tudelft.nl/uuid:46b9457b-7427-42cd-a595-0a2c7ced3c63","To charge or not to charge? Using Prospect Theory to model the tradeoffs of electric vehicle users","Pelka, S. (TU Delft Energie and Industrie; Fraunhofer Institute for Systems and Innovation Research ISI); Bosch, A. (Fraunhofer Institute for Systems and Innovation Research ISI); Chappin, E.J.L. (TU Delft Energie and Industrie); Liesenhoff, F. (Fraunhofer Institute for Systems and Innovation Research ISI); Kühnbach, M. (Fraunhofer Institute for Solar Energy Systems ISE); De Vries, Laurens (TU Delft Energie and Industrie)","","2024","Electric vehicle (EV) users who aim to become flexibility providers face a tradeoff between staying in control of charging and minimizing their electricity costs. The common practice is to charge immediately after plugging in and use more electricity than necessary. Changing this can increase the EV’s flexibility potential and reduce electricity costs. Our extended electricity cost optimization model systematically examines how different changes to this practice influence electricity costs. Based on the Prospect Theory and substantiated by empirical data, it captures EV users’ tradeoff between relinquishing control and reducing charging costs. Lowering the need to control charging results in disproportionally large savings in electricity costs. This finding incentivizes EV-users to relinquish even more control of charging. We analyzed changes to two charging settings that express the need for control. We found that changing only one setting offsets the other and reduces its positive effect on cost savings. Behavioral aspects, such as rebound effects and inertia that are widely documented in the literature, support this finding and underline the fit of our model extension to capture different charging behaviors. Our findings suggest that service providers should convince EV-users to relinquish control of both settings.","Direct load control; Discomfort cost; Electric vehicle; Prospect Theory; Prosumer; Smart charging","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:94156d87-7a0a-4af0-a5d0-c83827d67c19","http://resolver.tudelft.nl/uuid:94156d87-7a0a-4af0-a5d0-c83827d67c19","Micromechanics-based deep-learning for composites: Challenges and future perspectives","Mirkhalaf, Mohsen (University of Gothenburg); Rocha, I.B.C.M. (TU Delft Applied Mechanics)","","2024","During the last few decades, industries such as aerospace and wind energy (among others) have been remarkably influenced by the introduction of high-performance composites. One challenge, however, for modeling and designing composites is the lack of computational efficiency of accurate high-fidelity models. For design purposes, using conventional optimization approaches typically results in cumbersome procedures due to huge dimensions of the design space and high computational expense of full-field simulations. In recent years, deep learning techniques have been found to be promising methods to increase the efficiency and robustness of a variety of algorithms in multi-scale modeling and design of composites. In this perspective paper, a short overview of the recent developments in micromechanics-based machine learning for composites is given. More importantly, existing challenges for further model enhancements and future perspectives of the field development are elaborated.","Artificial neural networks; Composite materials; Micromechanics","en","journal article","","","","","","","","","","","Applied Mechanics","","",""
"uuid:c1c0ee8b-64f5-4a6b-a4f2-ce6421279e36","http://resolver.tudelft.nl/uuid:c1c0ee8b-64f5-4a6b-a4f2-ce6421279e36","Pressure drop non-linearities in material extrusion additive manufacturing: A novel approach for pressure monitoring and numerical modeling","de Vries, Sietse (Ultimaker); Schuller, Tomás (Universidade do Porto; INEGI); Galindo-Rosales, Francisco J. (Universidade do Porto); Fanzio, P. (TU Delft Micro and Nano Engineering)","","2024","Fused Filament Fabrication is an additive manufacturing technique in which molten thermoplastic polymers are extruded through a nozzle. Therefore, the interplay between the viscoelastic nature of the polymer melt, temperature, printing conditions and nozzle shape may lead to inconsistent extrusion. To improve the extrusion control and optimize the print-head performance, a better understanding of the flow process of the polymer melt both in the nozzle and the liquefier is needed. However, several challenges need to be overcome due to the complexity of gathering experimental data on the melt pressure in the nozzle and the lack of numerical models able to capture the full rheology of the molten polymer. This research introduces an innovative approach for monitoring the pressure within a material extrusion 3D printer's nozzle. This method involves utilizing a pin in direct contact with the molten material, which then transmits the applied force from the material to an externally mounted load cell. The setup provides reliable, repeatable pressure data in steady-state conditions for two nozzle geometries and at different extrusion flows and temperatures. Moreover, the Giesekus model enabled capturing the viscoelastic rheometric features of the melt, and the numerical predictions have been compared with the experimental data. Results show that the numerical model accurately describes the flow conditions in the nozzle and allows the estimation of the behavior of the melt in the liquefier zone, the area of the print-head where the filament is molten. It could be concluded that the backflow, which is the backward flow of the molten polymer in the gap between the filament and the liquefier towards the cold end, caused significant non-linearities in the total pressure drop measured in the feeders, which were related to normal forces induced by shear in that region.","3D printing; Elastic instabilities; Fused filament fabrication; Numerical simulations; Polylactic acid (PLA)","en","journal article","","","","","","","","","","","Micro and Nano Engineering","","",""
"uuid:7b36b99f-0616-4d8c-8a7e-a46f6b73abd2","http://resolver.tudelft.nl/uuid:7b36b99f-0616-4d8c-8a7e-a46f6b73abd2","A CPT-based multi-spring model for lateral monopile analysis under SLS conditions in sand","Tott-Buswell, Jacques (University of Nottingham); Prendergast, Luke J. (University of Nottingham); Gavin, Kenneth (TU Delft Geo-engineering)","","2024","Monopiles are the most common Offshore Wind Turbine (OWT) foundations due to their simplicity in design, fabrication, and installation. However, large new-generation turbines have led to significant changes in monopile dimensions, necessitating extensive finite element analyses and ground investigations to meet design requirements. While Cone Penetration Test (CPT)-based p-y methods can analyse slender pile lateral behaviour, they often miss additional resistance mechanisms relevant to rigid monopiles. This paper introduces CPT-informed resistance mechanisms for monopiles to incorporate additional lateral resistances beyond p-y modelling capabilities. Distributed moment–rotation (m-θ) springs are defined by repurposing CPT-based axial capacity estimation methods for piles; and pile tip shear and moment springs are informed by approximating a residual bearing stress post-installation using local CPT qc values. The performance of the multi-spring model is appraised against data reported from monotonic pile pushover tests conducted at two sand sites. Results show that the multi-spring model is capable of predicting pile head deflections reasonably well within serviceability deflection limits against the reported test data, but ultimate failure loads cannot be predicted using the proposed model. A clear sensitivity in pile response to local variations in CPT qc is demonstrated.","In-situ testing; Numerical modelling; Offshore engineering; Piles & piling; Soil–structure interaction","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:79541ea7-57a4-4625-8c64-366157e39961","http://resolver.tudelft.nl/uuid:79541ea7-57a4-4625-8c64-366157e39961","Image scanning microscopy: a vectorial physical optics analysis","Hung, S. (TU Delft Team Carlas Smith); Kalisvaart, D. (TU Delft Team Carlas Smith); Smith, C.S. (TU Delft BN/Nynke Dekker Lab; TU Delft ImPhys/Rieger group; TU Delft Team Carlas Smith)","","2024","Image scanning microscopy (ISM) achieves resolution beyond the diffraction limit by a factor of √2. However, prior ISM research predominantly employs scalar diffraction theory, neglecting critical physical effects such as polarization, aberrations, and Stokes shift. This paper presents a comprehensive vectorial ISM point spread function (PSF) model that accounts for these phenomena. By considering the effect of polarization in emission and excitation paths, as well as aberrations and Stokes shift, our model provides a more accurate representation of ISM. We analyze the differences between scalar and vectorial theories in ISM and investigate the impact of pinhole size and aberration strength on resolution. At a numerical aperture of 1.2, the full width half maximum (FWHM) discrepancy between scalar and vectorial ISM PSFs can reach 45 nm, representing a 30% deviation from the vectorial model. Additionally, we explore multiphoton excitation in ISM and observe increased FWHM for 2-photon and 3-photon excitation compared to 1-photon excitation. The FWHM of the 2-photon excitation ISM PSF increases by 20% and the FWHM of the 3-photon excitation ISM PSF increases by 28% compared to the 1-photon excitation ISM. In addition, we found that the optimal sweep factor for 2-photon ISM is 1.22, and the optimal sweep factor of 3-photon ISM is 1.12 instead of the 2 predicted by the one-photon scalar ISM theory. Our work improves the understanding of ISM and contributes to its advancement as a high-resolution imaging technique.","","en","journal article","","","","","","","","","","","Team Carlas Smith","","",""
"uuid:8dd22140-be36-4559-9f93-eeede35725ec","http://resolver.tudelft.nl/uuid:8dd22140-be36-4559-9f93-eeede35725ec","Efficient and fail-safe quantum algorithm for the transport equation","Schalkers, M.A. (TU Delft Numerical Analysis); Möller, M. (TU Delft Numerical Analysis)","","2024","In this paper we present a scalable algorithm for fault-tolerant quantum computers for solving the transport equation in two and three spatial dimensions for variable grid sizes and discrete velocities, where the object walls are aligned with the Cartesian grid, the relative difference of velocities in each dimension is bounded by 1 and the total simulated time is dependent on the discrete velocities chosen. We provide detailed descriptions and complexity analyses of all steps of our quantum transport method (QTM) and present numerical results for 2D flows generated in Qiskit as a proof of concept. Our QTM is based on a novel streaming approach which leads to a reduction in the amount of CNOT gates required in comparison to state-of-the-art quantum streaming methods. As a second highlight of this paper we present a novel object encoding method, that reduces the complexity of the amount of CNOT gates required to encode walls, which now becomes independent of the size of the wall. Finally we present a novel quantum encoding of the particles' discrete velocities that enables a linear speed-up in the costs of reflecting the velocity of a particle, which now becomes independent of the amount of velocities encoded. Our main contribution consists of a detailed description of a fail-safe implementation of a quantum algorithm for the reflection step of the transport equation that can be readily implemented on a physical quantum computer. This fail-safe implementation allows for a variety of initial conditions and particle velocities and leads to physically correct particle flow behavior around the walls, edges and corners of obstacles. Combining these results we present a novel and fail-safe quantum algorithm for the transport equation that can be used for a multitude of flow configurations and leads to physically correct behavior. We finally show that our approach only requires O(nwng2+dntvnvmax2) CNOT gates, which is quadratic in the amount of qubits necessary to encode the grid and the amount of qubits necessary to encode the discrete velocities in a single spatial dimension. This complexity result makes our approach superior to state-of-the-art approaches known in the literature.","Quantum algorithm; Quantum computational fluid dynamics; Quantum computing; Transport equation","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:c545502a-55a9-4654-aa57-29159b06e9b1","http://resolver.tudelft.nl/uuid:c545502a-55a9-4654-aa57-29159b06e9b1","Co-designing a research agenda for climate adaptation in El Salvador's coffee sector: A transdisciplinary perspective","Teodoro Morales, J.D. (TU Delft Transport and Logistics); Marselis, Suzanne (Universiteit Leiden); Maiello, A. (Universiteit Leiden); Häger, Achim (Universiteit Leiden)","","2024","The inclusion of social actors is widely acknowledged as a precondition for just and sustainable adaptation strategies to climate change. The integration of diverse types of scientific and local knowledge contributes to a better understanding of problems and increases the relevance of science at the local scale. In this study, we - an interdisciplinary team of scientists - employed a transdisciplinary methodology to enable the discussion of collaborative action the Salvadoran coffee sector needs to adapt to current and future impacts of climate change. Through a stakeholder encounter we elicited knowledge exchange among stakeholders to generate (i) a collective awareness of the experiences of climate impacts and (ii) outline a research agenda to facilitate a transdisciplinary climate change adaptation strategy. We used a suite of standard and participatory data-gathering methods, including desk research, in-depth informal conversations, questionnaires, field visits, small-group discussions, and a one-day workshop. In this paper, we present the methodological approach and the outcomes of the transdisciplinary research process. We ultimately outline a collectively generated research agenda using the input of stakeholders who partook in the workshop.","Agriculture; Climate resilience; Research co-design; Salvadoran coffee; Stakeholder encounter; Transdisciplinary research","en","journal article","","","","","","","","","","","Transport and Logistics","","",""
"uuid:5efd5ddb-579d-4d2f-85b2-15e229cc4dc7","http://resolver.tudelft.nl/uuid:5efd5ddb-579d-4d2f-85b2-15e229cc4dc7","Combined Fabrication and Performance Evaluation of TOPCon Back-Contact Solar Cells with Lateral Power Metal-Oxide-Semiconductor Field-Effect Transistors on a Single Substrate","van Nijen, D.A. (TU Delft Photovoltaic Materials and Devices); Stevens, Tristan (Student TU Delft); Mercimek, Yavuzhan (Student TU Delft); Yang, G. (TU Delft Photovoltaic Materials and Devices); van Swaaij, R.A.C.M.M. (TU Delft Photovoltaic Materials and Devices); Zeman, M. (TU Delft Photovoltaic Materials and Devices); Isabella, O. (TU Delft Photovoltaic Materials and Devices); Manganiello, P. (TU Delft Photovoltaic Materials and Devices)","","2024","Nowadays, an increasing share of photovoltaic (PV) systems makes use of module- or submodule-level power electronics (PE). Furthermore, PE is used in stand-alone devices powered by PV-storage solutions. One way to facilitate further implementation of PE in PV applications is to integrate PE components into crystalline silicon PV cells. Herein, the COSMOS device is introduced, denoting COmbined Solar cell and metal-oxide-semiconductor field-effect transistor (MOSFET). Specifically, the combined manufacturing of lateral power MOSFETs and interdigitated back contact solar cells with tunnel-oxide passivated contacts (TOPCon) on a single wafer is reported. Many steps of the proposed process flow are used for the fabrication of both devices, enabling cost-effective integration of the MOSFET. Both n-type solar cells with integrated p-channel MOSFETs (PMOS) and p-type solar cells with integrated n-channel MOSFETs (NMOS) are successfully manufactured. NMOS devices perform better in achieving low on-resistance, while PMOS devices exhibit lower leakage currents. Furthermore, the study reveals integration challenges where off-state leakage currents of the MOSFET can increase due to illumination and specific configurations of monolithic interconnections between the MOSFET and the solar cell. Nevertheless, for both n-type and p-type solar cells, efficiencies exceeding 20% are achieved, highlighting the potential of the proposed process for COSMOS devices.","COSMOS; crystalline silicon; integration; interdigitated back contact; monolithic integration; MOSFET; photovoltatronics; polycrystalline silicon on oxide; power electronics; tunnel-oxide passivated contacts","en","journal article","","","","","","","","","","","Photovoltaic Materials and Devices","","",""
"uuid:08e0f52f-c2ce-49a9-8d6f-a4f7c97a5145","http://resolver.tudelft.nl/uuid:08e0f52f-c2ce-49a9-8d6f-a4f7c97a5145","Unravelling corrosion degradation of aged aircraft components protected by chromate-based coatings","Cornet, A.J. (TU Delft Team Arjan Mol; Royal Netherlands Air Force); Homborg, A.M. (TU Delft Team Arjan Mol; Netherlands Defence Academy); Ravi Anusuyadevi, P. (TU Delft Team Arjan Mol); 't Hoen-Velterop, L. (National Aerospace Laboratory, Marknesse); Mol, J.M.C. (TU Delft Team Arjan Mol)","","2024","Despite extensive research, eliminating hexavalent chromium-based inhibitors from aerospace coatings remains challenging due to a lack of understanding of coating degradation during aircraft service. This study addresses the issue by investigating the protective mechanisms and aging processes of chromate-containing coatings on aircraft components after service for over 35 years. Four aircraft parts underwent visual inspection, disassembly, and analysis using scanning electron microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). While most coating areas remained intact after extended use, three distinct degradation modes were identified: tip erosion, corrosion around rivets, and corrosion around fasteners at the leading edge. These findings reveal the complexity of corrosion protection, emphasizing that hexavalent chromium-containing coatings may not offer comprehensive protection at local design heterogeneities. The study also highlights the need to revisit traditional laboratory analysis protocols based on accelerated corrosion testing of oversimplified sample configurations, given the revealed end-of-service failure mechanisms.","Aerospace engineering; Structures; Aluminium alloy; Composites; Fasteners; Microscopic characterization and microanalysis; Corrosion; Manufacturing defect; Isolation; Drain holes","en","journal article","","","","","","","","","","","Team Arjan Mol","","",""
"uuid:73c6a47d-8747-4978-a06e-d0005e7ea0c6","http://resolver.tudelft.nl/uuid:73c6a47d-8747-4978-a06e-d0005e7ea0c6","Evolution of automated weakness detection in Ethereum bytecode: a comprehensive study","di Angelo, Monika (Technische Universität Wien; INESC-ID); Durieux, T. (TU Delft Software Engineering); Ferreira, João F. (INESC-ID; University of Lisbon); Salzer, Gernot (Technische Universität Wien; INESC-ID)","","2024","Blockchain programs (also known as smart contracts) manage valuable assets like cryptocurrencies and tokens, and implement protocols in domains like decentralized finance (DeFi) and supply-chain management. These types of applications require a high level of security that is hard to achieve due to the transparency of public blockchains. Numerous tools support developers and auditors in the task of detecting weaknesses. As a young technology, blockchains and utilities evolve fast, making it challenging for tools and developers to keep up with the pace. In this work, we study the robustness of code analysis tools and the evolution of weakness detection on a dataset representing six years of blockchain activity. We focus on Ethereum as the crypto ecosystem with the largest number of developers and deployed programs. We investigate the behavior of single tools as well as the agreement of several tools addressing similar weaknesses. Our study is the first that is based on the entire body of deployed bytecode on Ethereum’s main chain. We achieve this coverage by considering bytecodes as equivalent if they share the same skeleton. The skeleton of a bytecode is obtained by omitting functionally irrelevant parts. This reduces the 48 million contracts deployed on Ethereum up to January 2022 to 248 328 contracts with distinct skeletons. For bulk execution, we utilize the open-source framework SmartBugs that facilitates the analysis of Solidity smart contracts, and enhance it to accept also bytecode as the only input. Moreover, we integrate six further tools for bytecode analysis. The execution of the 12 tools included in our study on the dataset took 30 CPU years. While the tools report a total of 1 307 486 potential weaknesses, we observe a decrease in reported weaknesses over time, as well as a degradation of tools to varying degrees.","Blockchain; Bytecode; Debugging; Detection tools; Ethereum; EVM; Program analysis; Reproducible Bugs; Smart contracts; Vulnerability","en","journal article","","","","","","","","","","","Software Engineering","","",""
"uuid:47a67052-fd5a-4504-a2ef-bf437d141b46","http://resolver.tudelft.nl/uuid:47a67052-fd5a-4504-a2ef-bf437d141b46","Reassessing tin circularity and criticality","Bradley, J.E. (TU Delft Policy Analysis); Auping, Willem L. (TU Delft Policy Analysis); Kleijn, René (Universiteit Leiden); Kwakkel, J.H. (TU Delft Policy Analysis); Sprecher, B. (TU Delft Design for Sustainability)","","2024","Tin is an important metal for society with a high risk of supply disruptions. It is, therefore, classified as a critical material in many parts of the world. An exception is the European Union, for which tin was classified as a non-critical material in 2023. However, there are many discrepancies in the literature regarding the definitions and values of the indicators used to determine tin criticality in general, and recycling indicators in particular. Values for end-of-life recycling rate (EoL RR) range between 20% and 75%, and values for end-of-life recycling input rate (EoL RIR) range between 11% and 32%. In this paper, we critically assess the circularity and criticality indicator values for tin and calculate new values using material flow analysis. The new values for tin recycling indicators are lower than those used in most previous research, with a global EoL RR of 16% and an EoL RIR of 11% in 2017. Based on the updated recycling values, combined with a highly concentrated supply, high import reliance, and difficult substitution, we argue that the European Union should classify tin as a critical material. This reclassification can lead to more policy attention for tin, which can help reduce the impact of future supply disruptions and increase the resilience of the European and global tin supply chains.","circular economy; critical materials; European union; industrial ecology; material flow analysis; recycling","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:e0191c85-f46b-4786-821c-59adeb24fa5c","http://resolver.tudelft.nl/uuid:e0191c85-f46b-4786-821c-59adeb24fa5c","Dataset on the tested and simulated response of thick cold-formed circular hollow sections under cyclic loading","Sadowski, Adam Jan (Imperial College London); Wong, W.J. (TU Delft Ship and Offshore Structures); Li, Sai Chung Simon (Imperial College London); Málaga-Chuquitaype, Christian (Imperial College London)","","2024","This article describes a dataset used to calibrate a finite element model of a thick circular hollow section (CHS) with varying d/t (diameter to thickness) ratio under cyclic loading which may be used as a computational model validation benchmark by researchers working on similar problems in structural and mechanical engineering. The test data consists of seven cold-formed S335J2H steel CHS tube specimens tested to buckling failure in low-cycle fatigue under a three-point bending arrangement, instrumented with discrete strain gauges, displacement transducers and string potentiometers together with continuous surface deformation fields obtained by two pairs of digital image correlation (DIC) cameras. ‘Half-cycle’ material data from the uniaxial tensile testing of dog-bone coupons is also provided. Comparisons between measured and simulated entities such as midspan forces, moments, displacements and mean curvatures can be obtained with MATLAB processing scripts. Complete ABAQUS model input files are also provided to aid in benchmarking.","Circular hollow section; Cyclic loading; Digital image correlation; Finite element analysis; Kinematic hardening; Seismic design","en","journal article","","","","","","","","","","","Ship and Offshore Structures","","",""
"uuid:6e514724-46b2-4868-952a-5da254ea1c4c","http://resolver.tudelft.nl/uuid:6e514724-46b2-4868-952a-5da254ea1c4c","The interplay of collagen, macrophages, and microcalcification in atherosclerotic plaque cap rupture mechanics","Jansen, Imke (Erasmus MC); Cahalane, Rachel (National University of Ireland Galway; Harvard Medical School); Hengst, Ranmadusha (Erasmus MC); Akyildiz, A.C. (TU Delft Medical Instruments & Bio-Inspired Technology; Erasmus MC); Farrell, Eric (Erasmus MC); Gijsen, F.J.H. (TU Delft Medical Instruments & Bio-Inspired Technology; Erasmus MC); Aikawa, Elena (Harvard Medical School); van der Heiden, Kim (Erasmus MC); Wissing, Tamar (Erasmus MC)","","2024","The rupture of an atherosclerotic plaque cap overlying a lipid pool and/or necrotic core can lead to thrombotic cardiovascular events. In essence, the rupture of the plaque cap is a mechanical event, which occurs when the local stress exceeds the local tissue strength. However, due to inter- and intra-cap heterogeneity, the resulting ultimate cap strength varies, causing proper assessment of the plaque at risk of rupture to be lacking. Important players involved in tissue strength include the load-bearing collagenous matrix, macrophages, as major promoters of extracellular matrix degradation, and microcalcifications, deposits that can exacerbate local stress, increasing tissue propensity for rupture. This review summarizes the role of these components individually in tissue mechanics, along with the interplay between them. We argue that to be able to improve risk assessment, a better understanding of the effect of these individual components, as well as their reciprocal relationships on cap mechanics, is required. Finally, we discuss potential future steps, including a holistic multidisciplinary approach, multifactorial 3D in vitro model systems, and advancements in imaging techniques. The obtained knowledge will ultimately serve as input to help diagnose, prevent, and treat atherosclerotic cap rupture.","Atherosclerosis; Collagen; Macrophages; Microcalcifications; Tissue mechanics","en","review","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:c5ac5edc-9c2a-4653-8548-9f31273d8f28","http://resolver.tudelft.nl/uuid:c5ac5edc-9c2a-4653-8548-9f31273d8f28","Structural and Optical Properties of Thin Film β-Ta upon Exposure to Hydrogen to Asses Its Applicability as Hydrogen Sensing Material","Bannenberg, L.J. (TU Delft RID/TS/Instrumenten groep); Verhoeff, D. (TU Delft Mechanical, Maritime and Materials Engineering); Jonckers Newton, Nick (Student TU Delft); Thijs, M.A. (TU Delft RID/TS/Technici Pool); Schreuders, H. (TU Delft ChemE/O&O groep)","","2024","Here, we study the structural and optical properties of tetragonal β-tantalum-sputtered thin films both ex situ and when exposed to hydrogen, with a focus on optical hydrogen sensing applications. Using optical transmission measurements, out-of-plane and in-plane X-ray diffraction, and X-ray and neutron reflectometry, we show that thin film β-tantalum gradually, reversibly, and hysteresis-freely absorbs hydrogen with an increasing hydrogen pressure/concentration. The gradual absorption of hydrogen with increasing hydrogen concentrations induces a change in the optical transmission and reflection. These quantities change reversibly and are hysteresis-free over at least 5 orders of magnitude in hydrogen pressure/concentration, making β-tantalum a suitable hydrogen sensing material. At all partial hydrogen pressures studied, we observe that the volumetric expansion, hydrogen-to-metal ratio, and lattice expansion are substantially smaller than for body-centered cubic α-tantalum.","metal hydrides; neutron reflectometry; optical hydrogen sensing; tantalum; thin films; X-ray diffraction","en","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","","RID/TS/Instrumenten groep","","",""
"uuid:df2099cc-d366-41e7-a04a-e5af41e10edc","http://resolver.tudelft.nl/uuid:df2099cc-d366-41e7-a04a-e5af41e10edc","PVA-TiO2 Nanocomposite Hydrogel as Immobilization Carrier for Gas-to-Liquid Wastewater Treatment","Surkatti, Riham (Qatar University); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Hussein, Ibnelwaleed A. (Qatar University); El-Naas, Muftah H. (Qatar University)","","2024","This study investigates the development of polyvinyl alcohol (PVA) gel matrices for biomass immobilization in wastewater treatment. The PVA hydrogels were prepared through a freezing–thawing (F-T) cross-linking process and reinforced with high surface area nanoparticles to improve their mechanical stability and porosity. The PVA/nanocomposite hydrogels were prepared using two different nanoparticle materials: iron oxide (Fe3O2) and titanium oxide (TiO2). The effects of the metal oxide nanoparticle type and content on the pore structure, hydrogel bonding, and mechanical and viscoelastic properties of the cross-linked hydrogel composites were investigated. The most durable PVA/nanoparticles matrix was then tested in the bioreactor for the biological treatment of wastewater. Morphological analysis showed that the reinforcement of PVA gel with Fe2O3 and TiO2 nanoparticles resulted in a compact nanocomposite hydrogel with regular pore distribution. The FTIR analysis highlighted the formation of bonds between nanoparticles and hydrogel, which caused more interaction within the polymeric matrix. Furthermore, the mechanical strength and Young’s modulus of the hydrogel composites were found to depend on the type and content of the nanoparticles. The most remarkable improvement in the mechanical strength of the PVA/nanoparticles composites was obtained by incorporating 0.1 wt% TiO2 and 1.0 wt% Fe2O3 nanoparticles. However, TiO2 showed more influence on the mechanical strength, with more than 900% improvement in Young’s modulus for TiO2-reinforced PVA hydrogel. Furthermore, incorporating TiO2 nanoparticles enhanced hydrogel stability but did not affect the biodegradation of organic pollutants in wastewater. These results suggest that the PVA-TiO2 hydrogel has the potential to be used as an effective carrier for biomass immobilization and wastewater treatment.","biomass; compression strength; nano-gel; polyvinyl alcohol (PVA); porosity; water purification","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:3aca29e3-be8a-445d-beb7-a978d5a2d4d6","http://resolver.tudelft.nl/uuid:3aca29e3-be8a-445d-beb7-a978d5a2d4d6","Effects on voice hearing distress and social functioning of unguided application of a smartphone app — A randomized controlled trial","Jongeneel, Alyssa (Vrije Universiteit Amsterdam; Parnassia Psychiatric Institute); Delespaul, Philippe (Universiteit Maastricht; Mondriaan Mental Health Centre, Heerlen); Tromp, N. (TU Delft Design Aesthetics); Scheffers, Dorien (Parnassia Psychiatric Institute); van der Vleugel, Berber (GGZ Noord-Holland Noord, Alkmaar; Viersprong Institute for Personality Disorders, Amsterdam); de Bont, Paul (Land van Cuijck en Noord Limburg); Kikkert, Martijn (Arkin BasisGGZ); Croes, Carlos F. (GGz Centraal); van den Berg, David (Vrije Universiteit Amsterdam; Parnassia Psychiatric Institute)","","2024","Background: Temstem is a smartphone app developed with and for clinical voice hearing individuals with the aim to reduce their voice hearing distress and improve social functioning. Methods: A randomized controlled trial with adult outpatients suffering from distressing and frequent auditory verbal hallucinations (AVH) was conducted. Participants were randomized to unguided ‘Temstem+AVH monitoring’ or unguided ‘AVH monitoring only’ (control condition). Assessments were performed at baseline, post-intervention (week 5–6), and follow-up (week 9–10). Primary outcomes were voice hearing distress and social functioning, as measured with Experience Sampling Method (ESM), consisting of multiple daily questionnaires during six days. In addition, voices and mood were self-monitored with help of a daily reflective questionnaire. Analyses were linear regression models (intention-to-treat). Results: 44 Participants were allocated to Temstem and 45 to the control condition. No significant differences between the groups were found on both primary outcomes. Conclusion: Our results do not support the effectiveness of stand-alone use of Temstem versus symptom monitoring on voice hearing distress or social functioning in voice hearing individuals. In order to potentially improve effectiveness of an mHealth tool in a population of people with frequent and distressing voices, we recommend to involve persons with lived experience in all stages of development and research; to thoroughly test the (technological) usability before performing an RCT; to test whether guidance of a therapist is needed to optimize effectiveness; and to provide prompts to remind the user to actually use the tool.","Auditory verbal hallucinations; ESM; Mhealth; Psychosis; Voice hearing; Voices","en","journal article","","","","","","","","","","","Design Aesthetics","","",""
"uuid:78f97eb2-bb20-439a-85b4-9cb0f6d634b0","http://resolver.tudelft.nl/uuid:78f97eb2-bb20-439a-85b4-9cb0f6d634b0","A column-generation matheuristic approach for optimizing first-mile ridesharing services with publicly- and privately-owned autonomous vehicles","He, P. (TU Delft Transport Engineering and Logistics; Shanghai Jiao Tong University); Jin, Jian Gang (Shanghai Jiao Tong University); Trépanier, Martin (Polytechnique Montreal; Centre interuniversitaire de recherche sur les réseaux d’entreprise, la logistique et le transport (CIRRELT)); Schulte, F. (TU Delft Transport Engineering and Logistics)","","2024","The burden of first-mile connection to public transit stations is a key barrier that discourages riders from taking public transportation. Public transit agencies typically operate a modest fleet of vehicles to provide first-mile services due to the high operating costs, thus failing to adequately meet the first-mile travel demands, especially during peak hours. At the same time, private cars are underutilized and have a lot of idle time. With the emergence of self-driving vehicles, new opportunities for addressing the current dilemma arise, such as integrating idle private self-driving vehicles to provide first-mile services, which is beneficial for public transportation agencies to provide high-quality services at low costs. This study investigates the first-mile ridesharing problem in which public transit agencies utilize idle privately-owned autonomous vehicles to dynamically inflate their fleet. This problem is more challenging in decision-making than conventional first-mile problems, as it involves decisions on heterogeneous fleet scheduling, vehicle routing, and time scheduling, all while taking into account the service quality for riders. To address this problem, an arc-based mixed-integer linear programming (MILP) model and a trip-based set-partitioning model are developed, both aiming to minimize total operational costs. To identify promising trips, we propose a tailored labeling algorithm with a novel dominance rule, along with a time window shift algorithm to determine the best schedule. To yield high-quality solutions in a short computation time, a tailored column-generation matheuristic algorithm is introduced. A branch-and-price exact algorithm and an adaptive large neighborhood search algorithm are developed to assess the matheuristic algorithm. Numerical experiments are conducted to demonstrate the effectiveness and applicability of the proposed models and algorithms. Experiments also show that this kind of ridesharing service can provide low-cost and high-quality services for the first-mile problem.","Autonomous vehicles; Branch-and-price algorithm; Column-generation matheuristic algorithm; First-mile ridesharing; Public transportation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-10","","","Transport Engineering and Logistics","","",""
"uuid:fb48a2fc-ad91-4630-8ded-7c67c5f4ad61","http://resolver.tudelft.nl/uuid:fb48a2fc-ad91-4630-8ded-7c67c5f4ad61","Adjuvant holmium-166 radioembolization after radiofrequency ablation in early-stage hepatocellular carcinoma patients: a dose-finding study (HORA EST HCC trial)","Hendriks, P. (Leiden University Medical Center); Rietbergen, Daphne D.D. (Leiden University Medical Center); van Erkel, Arian R. (Leiden University Medical Center); Coenraad, Minneke J. (Leiden University Medical Center); Arntz, Mark J. (Radboud University Medical Center); Bennink, Roel J. (Universiteit van Amsterdam); Braat, Andries E. (Leiden University Medical Center); de Geus-Oei, L.F. (TU Delft RST/Radiation, Science and Technology; Leiden University Medical Center; University of Twente); Burgmans, M.C. (Leiden University Medical Center)","","2024","Purpose: The aim of this study was to investigate the biodistribution of (super-)selective trans-arterial radioembolization (TARE) with holmium-166 microspheres (166Ho-MS), when administered as adjuvant therapy after RFA of HCC 2–5 cm. The objective was to establish a treatment volume absorbed dose that results in an absorbed dose of ≥ 120 Gy on the hyperemic zone around the ablation necrosis (i.e., target volume). Methods: In this multicenter, prospective dose-escalation study in BCLC early stage HCC patients with lesions 2–5 cm, RFA was followed by (super-)selective infusion of 166Ho-MS on day 5–10 after RFA. Dose distribution within the treatment volume was based on SPECT-CT. Cohorts of up to 10 patients were treated with an incremental dose (60 Gy, 90 Gy, 120 Gy) of 166Ho-MS to the treatment volume. The primary endpoint was to obtain a target volume dose of ≥ 120 Gy in 9/10 patients within a cohort. Results: Twelve patients were treated (male 10; median age, 66.5 years (IQR, [64.3–71.7])) with a median tumor diameter of 2.7 cm (IQR, [2.1–4.0]). At a treatment volume absorbed dose of 90 Gy, the primary endpoint was met with a median absorbed target volume dose of 138 Gy (IQR, [127–145]). No local recurrences were found within 1-year follow-up. Conclusion: Adjuvant (super-)selective infusion of 166Ho-MS after RFA for the treatment of HCC can be administered safely at a dose of 90 Gy to the treatment volume while reaching a dose of ≥ 120 Gy to the target volume and may be a favorable adjuvant therapy for HCC lesions 2–5 cm. Trial registration: Clinicaltrials.gov NCT03437382.","Adjuvant therapy; Dose-escalation study; Hepatocellular carcinoma; Holmium-166; Radiofrequency ablation; Trans-arterial radioembolization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-08","","RST/Radiation, Science and Technology","","","",""
"uuid:c439c2a9-f5c0-48e8-9d65-e4a02d1c2eba","http://resolver.tudelft.nl/uuid:c439c2a9-f5c0-48e8-9d65-e4a02d1c2eba","Momentum Transport in Organized Shallow Cumulus Convection","Savazzi, A.C.M. (TU Delft Atmospheric Remote Sensing); Nuijens, Louise (TU Delft Atmospheric Remote Sensing); De Rooy, Wim (Royal Netherlands Meteorological Institute (KNMI)); Janssens, M. (TU Delft Atmospheric Remote Sensing; Wageningen University & Research); Siebesma, A.P. (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI))","","2024","This study investigates momentum transport in shallow cumulus clouds as simulated with the Dutch Atmospheric Large Eddy Simulation (DALES) for a 150 3 150 km2 domain east of Barbados during 9 days of EUREC4A. DALES is initialized and forced with the mesoscale weather model HARMONIE-AROME and subjectively reproduces observed cloud patterns. This study examines the evolution of momentum transport, which scales contribute to it, and how they modulate the trade winds. Daily-mean momentum flux profiles show downgradient zonal momentum transport in the subcloud layer, which turns countergradient in the cloud layer. The meridional momentum transport is nontrivial, with mostly downgradient transport throughout the trade wind layer except near the top of the surface layer and near cloud tops. Substantial spatial and temporal heterogeneity in momentum flux is observed with much stronger tendencies imposed in areas of organized convection. The study finds that while scales < 2 km dominate momentum flux at 200 m in unorganized fields, submesoscales O(2-20) km carry up to 50% of the zonal momentum flux in the cloud layer in organized fields. For the meridional momentum flux, this fraction is even larger near the surface and in the subcloud layer. The scale dependence of the momentum flux is not explained by changes in convective or boundary layer depth. Instead, the results suggest the importance of spatial heterogeneity, increasing horizontal length scales, and countergradient transport in the presence of organized convection.","Convective parameterization; Convective-scale processes; Large eddy simulations; Mesoscale processes; Momentum; Subtropics","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:7dbd86c2-4f14-4e4c-8b0e-a74a9f69c8a9","http://resolver.tudelft.nl/uuid:7dbd86c2-4f14-4e4c-8b0e-a74a9f69c8a9","The CCAP for graph products of operator algebras","Borst, M.J. (TU Delft Analysis)","","2024","For a simple graph Γ and for unital C*-algebras with GNS-faithful states (Av,φv) for v∈VΓ, we consider the reduced graph product (A,φ)=⁎v,Γ(Av,φv), and show that if every C*-algebra Av has the completely contractive approximation property (CCAP) and satisfies some additional condition, then the graph product has the CCAP as well. The additional condition imposed is satisfied in natural cases, for example for the reduced group C*-algebra of a discrete group G that possesses the CCAP. Our result is an extension of the result of Ricard and Xu in [28, Proposition 4.11] where they prove this result under the same conditions for free products. Moreover, our result also extends the result of Reckwerdt in [27, Theorem 5.5], where he proved for groups that weak amenability with Cowling-Haagerup constant 1 is preserved under graph products. Our result further covers many new cases coming from Hecke-algebras and discrete quantum groups.","Completely contractive approximation property (CCAP); Graph products of operator algebras; Khintchine inequalities; Weak amenability with Cowling-Haagerup constant 1","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:e88da30d-3e7a-4d70-bf5c-c4982f02d2c8","http://resolver.tudelft.nl/uuid:e88da30d-3e7a-4d70-bf5c-c4982f02d2c8","Developing Crowdfunding-Based Financing Scheme to Increase Potential of Micro, Small, and Medium Business in Urban Green Space","Berawi, Mohammed Ali (Universitas Indonesia); Sari, Mustika (Universitas Indonesia); Lumbantobing, Vanana (Universitas Indonesia); Susilowati, Suci Indah (Universitas Indonesia); Susantono, Bambang (Universitas Indonesia; Universitas Diponegoro); Woodhead, Roy (Sheffield Hallam University); Sejatiguna, P.M. (TU Delft Design & Construction Management; Universitas Indonesia)","","2024","Micro, Small, and Medium Business (MSMEs) are vital to the Indonesian economic development, and the government is focusing on this sector for post-pandemic recovery. There is an emphasis on infrastructure such as urban green spaces, or Ruang Terbuka Hijau (RTH). RTHs have untapped potential as centers for agricultural and processing MSMEs. However, these businesses often face financing challenges, prompting the exploration of alternative scheme like crowdfunding. Therefore, this study aimed to (1) explore how RTH lands can be leveraged for local economic activities, and (2) devise a public fund-based crowdfunding financing model. Using RTH Kalijodo in Jakarta as a case study, the study included literature reviews, benchmarking, fieldwork, and Life Cycle Cost (LCC) analysis. The results show the need for the development of vertical hydroponics, tilapia farming, and tilapia fillet processing business in RTH Kalijodo. Financial analyses, including IRR calculations exceeding the 10.41% WACC, a positive NPV, and a payback period under five years, show the financial viability of these sectors.","Crowdfunding; Life cycle cost; MSMEs; Urban green space","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:60d5092f-1ce7-46ab-8d7c-3825679317da","http://resolver.tudelft.nl/uuid:60d5092f-1ce7-46ab-8d7c-3825679317da","Prospective life cycle inventory datasets for conventional and hybrid-electric aircraft technologies","Thonemann, Nils (Technical University of Denmark); Saavedra-Rubio, Karen (Technical University of Denmark); Pierrat, Eleonore (Technical University of Denmark); Dudka, Katarzyna (Technical University of Denmark); Bangoura, Mathilde (MAHYTEC); Baumann, Nils (Proton Motor Fuel Cell GmbH); Bentheimer, Christian (Friedrich-Alexander-Universität Erlangen-Nürnberg); Caliandro, Priscilla (Bern University of Applied Sciences); De Breuker, R. (TU Delft Group De Breuker)","","2024","Hybrid-electric aircraft represent a promising solution for the urgent need to decarbonize short-haul flights and bolster aviation sustainability. Nevertheless, the realization of hybrid-electric aircraft demands rigorous environmental impact analysis, given the substantial investments, time, and research required for technology development. This study offers a comprehensive life cycle inventory spanning the years 2030, 2040, and 2050 for both conventional and hybrid-electric aircraft configurations. Our inventory datasets are meticulously constructed through a systematic approach, ensuring data harmonization by drawing upon scientific literature, industry expertise, and primary data sources. This extensive dataset encompasses all pertinent systems necessary to model the environmental footprint of flights covering distances ranging from 200 to 600 nautical miles, utilizing a 50-passenger aircraft with the ATR42 as a reference model. Additionally, we furnish supplemental data for end-of-life considerations and uncertainty analysis. The systems under examination include the airframe, powertrain, power electronics and drives, batteries, fuel cells, hydrogen onboard storage, airport infrastructure, and battery charging stations. Notably, the carbon footprint of conventional aircraft aligns with data from the ecoinvent v3.8 database; however, our provided datasets are more than tenfold more detailed and incorporate a forward-looking perspective. These meticulously curated life cycle inventories can be amalgamated to simulate the potential environmental ramifications of conventional aircraft powered by kerosene or alternative aviation fuels, hybrid-electric aircraft utilizing battery technology, and hybrid-electric aircraft employing hydrogen as a fuel in conjunction with batteries. In this context, our findings play a pivotal role in nurturing the development of technology roadmaps that prioritize environmental sustainability within the realm of regional aviation.","Aviation; Data collection; Environmental sustainability; Industrial ecology; LCA; Prospective life cycle assessment; Transport","en","journal article","","","","","","","","","","","Group De Breuker","","",""
"uuid:e75da446-5b4a-4de6-9867-176a6d4e5037","http://resolver.tudelft.nl/uuid:e75da446-5b4a-4de6-9867-176a6d4e5037","Explaining Value Capture Implementation in New York, London, and Copenhagen: Negotiating Distributional Effects","van Zoest, S.P. (TU Delft Practice Chair Urban Area Development); Daamen, T.A. (TU Delft Urban Development Management)","","2024","Value capture (VC) is widely cited as a method for local authorities to provide urban public goods to their cities in the face of fiscal stress. Its application in practice however remains limited. In this article, we aim to explain the implementation process of VC as a strategy to fund public transportation infrastructure through case studies in London, New York, and Copenhagen. Adopting a theory of gradual institutional change, we argue that the implementation of VC depends on the capacity to change distributional institutions that are inherently contested. Particularly relevant is the role of the beneficiary, whose support of VC is necessary but not likely. Our results show that a strategic urban development project can act as a driver to overcome this barrier, but that this driver can, simultaneously, also hinder the institutionalization potential of a VC strategy. We therefore suggest that, for VC strategies to become more commonplace, sharing value uplifts among beneficiaries must become more commonplace too.","institutional change; physical infrastructure; urban development; urban public policies; value capture","en","journal article","","","","","","Online First version.","","","","","Practice Chair Urban Area Development","","",""
"uuid:717e8a72-bb5f-4e68-8b77-fe2c67fbf702","http://resolver.tudelft.nl/uuid:717e8a72-bb5f-4e68-8b77-fe2c67fbf702","Cliquepolitik: Multimodal online discourse coalitions on CRISPR-Cas genome editing technology","Rojas-Padilla, Eduardo (Wageningen University & Research); Metze, T.A.P. (TU Delft Organisation & Governance); Dewulf, Art (Wageningen University & Research)","","2024","The influence of visualizations on decision-making about controversial policy issues is increasingly recognized in the political and policy sciences. In this paper, we explore how combinations of visuals and text on Twitter (now X) lead to the formation of networks of actors sharing similar textual and visual framings about a policy issue in an online setting, which we conceptualize as Multimodal Online Discourse Coalitions (MODCs). MODCs struggle over the meaning of contested policy issues. We examine multiple MODCs in 2018 in the context of the regulatory decisions in that year about CRISPR-Cas gene editing technology in the USA, Mercosur, and the EU. Based on an SNA and a qualitative visual and discursive analysis in three languages on Twitter in 2018 (covering in total ~ 427 k Tweets), we show that MODCs in English and Spanish focused on technocratic aspects of CRISPR-Cas, resembling the regulatory decisions in the USA and Mercosur. In Europe, next to technocratic MODCs, an MODC in French formed around ethical/normative framings of the consequences of CRISPR-Cas applications, using visuals of embryos to represent “GMO babies.” These visuals were emotional triggers in their framing of CRISPR technology. The ethical/normative framing reflected the argument brought to the CJEU by a group of French actors involved in the court case which categorized CRISPR-Cas as a GMO technology in the EU. These results suggest that the French MODC and their visualization was of influence on the EU decision-making process; however, more research is needed to verify the role of this online debate in the decision-making process.","CRISPR-Cas; discourse coalition; genome editing; multimodal framing; online public debate; policy controversies; technological governance","en","journal article","","","","","","","","","","","Organisation & Governance","","",""
"uuid:fa3a5bd1-02d6-4ba4-b7dc-3d6782cb6df6","http://resolver.tudelft.nl/uuid:fa3a5bd1-02d6-4ba4-b7dc-3d6782cb6df6","Random organic framework membranes with hierarchical channels for H2 separation","Luan, Liping (Tianjin University); Shi, Puxin (Tianjin University); Wang, Zhi (Tianjin University); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Liu, Xinlei (Tianjin University)","","2024","Novel membrane materials for H2 separation are wanted. How to overcome the “trade-off” between membrane permeability and selectivity is a tough challenge. Here we report new random organic framework membranes with benzimidazole and imine linkages to form hierarchical channels. Both high H2-selective and fast H2 transport pathways are created. The preparation parameters are thoroughly studied and the membrane structures are well characterized by SEM, AFM, NMR, XPS, gas sorption, etc. Effect of feed conditions on membrane performance, such as composition, pressure and temperature, is investigated. The membrane performance transcends the upper bounds of H2/CO2, H2/N2 and H2/CH4 with excellent stability.","Benzimidazole and imine linked polymer; H separation; Hierarchical channels; Random organic framework membranes","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-08","","","ChemE/Catalysis Engineering","","",""
"uuid:04d25e38-1ac5-4dd9-b6b3-9cf1f70bbdc8","http://resolver.tudelft.nl/uuid:04d25e38-1ac5-4dd9-b6b3-9cf1f70bbdc8","Multiscale modelling and experimental analysis of ultrasonic-assisted drilling of GLARE fibre metal laminates","Atif, Muhammad (Beijing Institute of Technology); Wang, Xibin (Beijing Institute of Technology); Xie, Lijing (Beijing Institute of Technology); Giasin, Khaled (University of Portsmouth); Ma, Yuan (Tsinghua University); Jiang, Chulin (Teesside University); Koklu, Ugur (Karamanoglu Mehmetbey University); Sinke, J. (TU Delft Group Sinke)","","2024","This study aims to evaluate the effectiveness of Ultrasonic-assisted drilling (UAD) of Glass laminate aluminium reinforced epoxy (GLARE) at high cutting speeds (Spindle speeds: 3000–7500 rpm; feed rates 300–750 mm/min) by analysing the thrust force and hole quality metrics (surface roughness, hole size, and burr formations. The research also presents numerical modelling of FMLs under conventional and UAD regimes to predict thrust force using ABAQUS/SIMULIA. The thrust force and exit burrs were reduced by up to 40.83 % and 80 %, respectively. The surface roughness metrics (Ra and Rz) were slightly higher using UAD but remained within the desirable limits of surface roughness for machined aeronautical structures. The discrepancy between the simulation and experimental results was adequate and did not exceed 15 %. The current study shows that it is feasible to drill holes in GLARE using higher cutting parameters and maintain excellent hole quality, which means increased productivity and reduced costs.","GLARE; Surface roughness; Thrust force; Ultrasonic assisted drilling","en","journal article","","","","","","","","","","","Group Sinke","","",""
"uuid:090488a2-8ca2-4a3d-afab-950d736c43b0","http://resolver.tudelft.nl/uuid:090488a2-8ca2-4a3d-afab-950d736c43b0","Recyclable Conjugated Polyelectrolyte Hydrogels for Pseudocapacitor Fabrication","Jiang, Yan (National University of Singapore); Vázquez, Ricardo Javier (National University of Singapore; Nanyang Technological University; Indiana University - Purdue University); McCuskey, Samantha R. (National University of Singapore; Nanyang Technological University); Yip, Benjamin Rui Peng (National University of Singapore); Quek, Glenn (National University of Singapore); Ohayon, David (National University of Singapore); Kundukad, Binu (Nanyang Technological University); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy); Bazan, Guillermo C. (National University of Singapore; Nanyang Technological University; University of California)","","2024","In alignment with widespread interest in carbon neutralization and sustainable practices, we disclose that conjugated polyelectrolyte (CPE) hydrogels are a type of recyclable, electrochemically stable, and environmentally friendly pseudocapacitive material for energy storage applications. By leveraging ionic-electronic coupling in a relatively fluid medium, one finds that hydrogels prepared using a fresh batch of an anionic CPE, namely, Pris-CPE-K, exhibit a specific capacitance of 32.6 ± 6.6 F g-1 in 2 M NaCl and are capable of 80% (26.1 ± 6.5 F g-1) capacitance retention after 100,000 galvanostatic charge-discharge (GCD) cycles at a current density (J) of 10 A g-1. We note that equilibration under a constant potential prior to GCD analysis leads to the K+ counterions in the CPE exchanging with Na+ and, thus, the relevant active material Pris-CPE-Na. It is possible to remove the CPE material from the electrochemical cell via extraction with water and to carry out a simple purification through dialysis to produce a recycled material, namely Re-CPE-Na. The recycling workup has no significant detrimental impact on the electrochemical performance. Specifically, Re-CPE-Na hydrogels display an initial specific capacitance of 26.3 ± 1.2 F g-1 (at 10 A g-1) and retain 77% of the capacitance after a subsequent 100,000 GCD cycles. Characterization by NMR, FTIR, and Raman spectroscopies, together with XPS and GPC measurements, revealed no change in the structure of the backbone or side chains. However, rheological measurements gave evidence of a slight loss in G′ and G′′. Overall, that CPE hydrogels display recyclability argues in favor of considering them as a novel materials platform for energy storage applications within an economically viable circular recycling strategy.","conjugated polyelectrolytes; cycling stability; energy storage; organic mixed ionic-electronic conductors; recyclable pseudocapacitive material","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-27","","","RST/Storage of Electrochemical Energy","","",""
"uuid:5b59bf07-cbe2-4b15-bed7-11cd5ba891ac","http://resolver.tudelft.nl/uuid:5b59bf07-cbe2-4b15-bed7-11cd5ba891ac","GRACE-FO radiation pressure modelling for accurate density and crosswind retrieval","Hladczuk, N.A. (TU Delft Astrodynamics & Space Missions); van den IJssel, J.A.A. (TU Delft Astrodynamics & Space Missions); Kodikara, T. (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Siemes, C. (TU Delft Astrodynamics & Space Missions); Visser, P.N.A.M. (TU Delft Space Engineering)","","2024","Uncertainties in radiation pressure modelling play a significant role in the thermospheric density and crosswind observations derived from the GRACE-FO accelerometer, especially during low solar activity. Under such conditions, the radiation pressure acceleration matches the magnitude of the aerodynamic acceleration along the track and exceeds it in the cross-track direction. The GRACE-FO mission has been operating for several years at such high altitudes during both low and rising solar activity, providing a perfect opportunity to study the effects of radiation pressure. This research uses ray tracing based on a high-fidelity satellite geometry model to calculate the radiation pressure acceleration. We numerically fine-tuned the coefficients describing the thermo-optical surface properties to obtain more accurate radiation pressure accelerations than those specified in the GRACE-FO mission manual. We also used in situ temperature measurements from thermistors on the solar arrays to model the satellite's thermal emission. These temperature measurements allowed a realistic setup of the thermal model, extended by the parameter describing the efficiency of the solar cells, and reproduced the acceleration of the thermal emission with an accuracy of RMS 0.148 nms−2. The combination of the updated thermal model and the fine-tuning of the surface coefficients improved the accuracy of the crosswind acceleration to an RMS of 0.55 nms−2, compared to an RMS of 4.22 nms−2 when using panel models and instantaneous thermal radiation. We compared the observed crosswind with two models: HWM14 and TIE-GCM. While both models capture most of the salient features of the observed crosswind, HWM14 shows particularly good agreement at high latitudes. Compared to the previously employed radiation pressure model, the crosswind observations have been improved in low and mid-latitudes, especially during periods of higher solar activity. Since the effect of radiation pressure is most significant in the crosswind direction, the effect on density was small compared to previously published datasets.","GRACE-FO; Neutral mass density; Neutral winds; Radiation pressure; Thermal emission; Thermosphere","en","journal article","","","","","","","","","","Space Engineering","Astrodynamics & Space Missions","","",""
"uuid:28077850-61f9-42b3-8626-5e6861619088","http://resolver.tudelft.nl/uuid:28077850-61f9-42b3-8626-5e6861619088","Diversity-Based Topology Optimization of Soft Robotic Grippers","Pinskier, Josh (The Commonwealth Scientific and Industrial Research Organisation (CSIRO)); Wang, Xing (The Commonwealth Scientific and Industrial Research Organisation (CSIRO)); Liow, Lois (The Commonwealth Scientific and Industrial Research Organisation (CSIRO)); Xie, Yue (University of Cambridge); Kumar, Prabhat (Indian Institute of Technology Hyderabad); Langelaar, Matthijs (TU Delft Computational Design and Mechanics); Howard, David (The Commonwealth Scientific and Industrial Research Organisation (CSIRO))","","2024","Soft grippers are ideal for grasping delicate, deformable objects with complex geometries. Universal soft grippers have proven effective for grasping common objects, however complex objects or environments require bespoke gripper designs. Multi-material printing presents a vast design-space which, when coupled with an expressive computational design algorithm, can produce numerous, novel, high-performance soft grippers. Finding high-performing designs in challenging design spaces requires tools that combine rapid iteration, simulation accuracy, and fine-grained optimization across a range of gripper designs to maximize performance, no current tools meet all these criteria. Herein, a diversity-based soft gripper design framework combining generative design and topology optimization (TO) are presented. Compositional pattern-producing networks (CPPNs) seed a diverse set of initial material distributions for the fine-grained TO. Focusing on vacuum-driven multi-material soft grippers, several grasping modes (e.g. pinching, scooping) emerging without explicit prompting are demonstrated. Extensive automated experimentation with printed multi-material grippers confirms optimized candidates exceed the grasp strength of comparable commercial designs. Grip strength, durability, and robustness is evaluated across 15,170 grasps. The combination of fine-grained generative design, diversity-based design processes, high-fidelity simulation, and automated experimental evaluation represents a new paradigm for bespoke soft gripper design which is generalizable across numerous design domains, tasks, and environments.","computational design; soft robotics; topology optimization","en","journal article","","","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:3f20a82a-5316-446b-b682-8f966a2a9d92","http://resolver.tudelft.nl/uuid:3f20a82a-5316-446b-b682-8f966a2a9d92","Public preferences for the allocation of societal resources over different healthcare purposes","Boxebeld, Sander (Erasmus Universiteit Rotterdam); Geijsen, Tom (Populytics B.V); Tuit, Charlotte (Populytics B.V); Exel, Job van (Erasmus Universiteit Rotterdam); Makady, Amr (Janssen-Cilag B.V); Maes, Laurence (Janssen-Cilag B.V); van Agthoven, Michel (Janssen-Cilag B.V); Mouter, N. (TU Delft Transport and Logistics; Populytics B.V)","","2024","Objective: Increasing healthcare expenditures require governments to make difficult prioritization decisions. Considering public preferences can help raise citizens’ support. Previous research has predominantly elicited preferences for the allocation of public resources towards specific treatments or patient groups and principles for resource allocation. This study contributes by examining public preferences for budget allocation over various healthcare purposes in the Netherlands. Methods: We conducted a Participatory Value Evaluation (PVE) choice experiment in which 1408 respondents were asked to allocate a hypothetical budget over eight healthcare purposes: general practice and other easily accessible healthcare, hospital care, elderly care, disability care, mental healthcare, preventive care by encouragement, preventive care by discouragement, and new and better medicines. A default expenditure was set for each healthcare purpose, based on current expenditures. Respondents could adjust these default expenditures using sliders and were presented with the implications of their adjustments on health and well-being outcomes, the economy, and the healthcare premium. As a constraint, the maximum increase in the mandatory healthcare premium for adult citizens was €600 per year. The data were analysed using descriptive statistics and a Latent Class Cluster Analysis (LCCA). Results: On average, respondents preferred to increase total expenditures on all healthcare purposes, but especially on elderly care, new and better medicines, and mental healthcare. Three preference clusters were identified. The largest cluster preferred modest increases in expenditures, the second a much higher increase of expenditures, and the smallest favouring a substantial reduction of the healthcare premium by decreasing the expenditure on all healthcare purposes. The analyses also demonstrated substantial preference heterogeneity between clusters for budget allocation over different healthcare purposes. Conclusions: The results of this choice experiment show that most citizens in the Netherlands support increasing healthcare expenditures. However, substantial heterogeneity was identified in preferences for healthcare purposes to prioritize. Considering these preferences may increase public support for prioritization decisions.","Healthcare expenditure; Participatory value evaluation (PVE); Priority-setting; Public preferences","en","journal article","","","","","","","","","","","Transport and Logistics","","",""
"uuid:e6472160-3d10-4a1c-8241-759fe215e85e","http://resolver.tudelft.nl/uuid:e6472160-3d10-4a1c-8241-759fe215e85e","Improving plant-level heat pump performance through process modifications","de Raad, B.W. (TU Delft Energie and Industrie); van Lieshout, Marit (Rotterdam University of Applied Sciences); Stougie, L. (TU Delft Energie and Industrie); Ramirez, Andrea (TU Delft ChemE/Chemical Engineering)","","2024","Heat pumps are a promising option to decarbonize the industrial sector. However, their performance at a plant-level can be affected by other process changes. In this work, process changes that improve the heat pump's performance have been identified using Process Change Analysis (PCA), where the background pinch point is used as a reference point for appropriate placement. The effects of the process changes on the heat pump's work requirements are studies by introducing exergy to PCA to form the split exergy grand composite curve. This graph shows the work potential of the streams connected to the heat pump and therefore its work targets. The framework is demonstrated in two case studies. In a biodiesel production plant, it allowed to identify technologies that enhance heat pump performance while reducing overall heating requirements. Here, a heat pump transfers 1.9 MW with a COP of 4.2 but incurs a 40 kW penalty for transferring heat above the background process's pinch temperature. Replacing the wet water washer with a membrane separation unit avoided this penalty, while drastically reducing energy requirements from 0.9 MW to 0.3 MW. in a vinyl chloride monomer-purification process, PCA showed how the extraction of heat by the heat pump impacted the formation of the background pinch, from which an implementation strategy was derived that increased the heat pump's plant-level performance by 6.5% with respect to standard implementation.","Exergy grand composite curve; Heat pumps; Pinch analysis; Process change analysis","en","journal article","","","","","","","","","","ChemE/Chemical Engineering","Energie and Industrie","","",""
"uuid:7990a9cb-3423-42dc-9dd3-139c4ac259f2","http://resolver.tudelft.nl/uuid:7990a9cb-3423-42dc-9dd3-139c4ac259f2","Time-dependent earthquake-fire coupling fragility analysis under limited prior knowledge: A perspective from type-2 fuzzy probability","Men, Jinkun (South China University of Technology; Guangdong Provincial Science and Technology Collaborative Innovation Center for Work Safety; Katholieke Universiteit Leuven); Chen, Guohua (South China University of Technology; Guangdong Provincial Science and Technology Collaborative Innovation Center for Work Safety); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Katholieke Universiteit Leuven; Universiteit Antwerpen)","","2024","Earthquake-triggered fire domino scenarios (E-FDSs) arise frequently from the interaction between earthquakes and chemical installations, resulting in catastrophic multi-hazard coupling events. The complicated mutually amplified phenomena between natural disasters and chemical accidents significantly aggravates the escalation of domino accidents, which has posed great challenges for modeling and preventing E-FDSs. Under this impetus, this work proposes an advanced type-2 fuzzy probabilistic methodology to obtain the time-dependent failure probability of steel cylindrical tanks (SCTs) subjected to the earthquake-fire sequence. To cope with the limited prior knowledge on E-FDSs, a basic universal is established to describe the fire resistance attenuation caused by the seismic damage. The coupling failure criterion of SCTs is formulated by a type-2 fuzzy time-dependent limit state equation. A credibility-based stochastic simulation algorithm is developed for the hybrid uncertainty analysis (combining ambiguity and stochasticity). The proposed methodology is validated by case studies of a 5000 m3 fixed roof tank. Compared to the existing accident probability model, the proposed methodology can not only capture the fire resistance attenuation caused by the seismic damage but also provide a dynamic estimation of tank failure probability with respect to the fire exposure time. The proposed methodology can effectively and dynamically capture the accident evolution process, which in turn helps mitigate and prevent the spatiotemporal propagation of domino effects.","Chemical Industrial Parks; Chemical Process Safety; Earthquake-triggered Fire Domino Scenarios; Multi-hazard Coupling Events; Steel Cylindrical Tank; Type-2 Fuzzy Possibility Theory","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-06","","","Safety and Security Science","","",""
"uuid:c87ae011-bca8-4dca-a055-07003d1c4fd1","http://resolver.tudelft.nl/uuid:c87ae011-bca8-4dca-a055-07003d1c4fd1","Trunk motion influences mechanical power estimates during wheelchair propulsion","van Dijk, M.P. (TU Delft Biomechanical Engineering); Hoozemans, Marco J.M. (Vrije Universiteit Amsterdam); Berger, M.A.M. (The Hague University of Applied Sciences); Veeger, H.E.J. (TU Delft Biomechatronics & Human-Machine Control)","","2024","In wheelchair sports, there is an increasing need to monitor mechanical power in the field. When rolling resistance is known, inertial measurement units (IMUs) can be used to determine mechanical power. However, upper body (i.e., trunk) motion affects the mass distribution between the small front and large rear wheels, thus affecting rolling resistance. Therefore, drag tests – which are commonly used to estimate rolling resistance – may not be valid. The aim of this study was to investigate the influence of trunk motion on mechanical power estimates in hand-rim wheelchair propulsion by comparing instantaneous resistance-based power loss with drag test-based power loss. Experiments were performed with no, moderate and full trunk motion during wheelchair propulsion. During these experiments, power loss was determined based on 1) the instantaneous rolling resistance and 2) based on the rolling resistance determined from drag tests (thus neglecting the effects of trunk motion). Results showed that power loss values of the two methods were similar when no trunk motion was present (mean difference [MD] of 0.6 ± 1.6 %). However, drag test-based power loss was underestimated up to −3.3 ± 2.3 % MD when the extent of trunk motion increased (r = 0.85). To conclude, during wheelchair propulsion with active trunk motion, neglecting the effects of trunk motion leads to an underestimated mechanical power of 1 to 6 % when it is estimated with drag test values. Depending on the required accuracy and the amount of trunk motion in the target group, the influence of trunk motion on power estimates should be corrected for.","Inertial measurement unit; Mechanical power; Rolling resistance force; Wheelchair propulsion; Wheelchair sports","en","journal article","","","","","","","","","","Biomechanical Engineering","Biomechatronics & Human-Machine Control","","",""
"uuid:b0128715-5e3f-4f08-8272-5592aed71551","http://resolver.tudelft.nl/uuid:b0128715-5e3f-4f08-8272-5592aed71551","From statistical relational to neurosymbolic artificial intelligence: A survey","Marra, Giuseppe (Katholieke Universiteit Leuven); Dumančić, S. (TU Delft Algorithmics); Manhaeve, Robin (Katholieke Universiteit Leuven); De Raedt, Luc (Katholieke Universiteit Leuven; Orebro University)","","2024","This survey explores the integration of learning and reasoning in two different fields of artificial intelligence: neurosymbolic and statistical relational artificial intelligence. Neurosymbolic artificial intelligence (NeSy) studies the integration of symbolic reasoning and neural networks, while statistical relational artificial intelligence (StarAI) focuses on integrating logic with probabilistic graphical models. This survey identifies seven shared dimensions between these two subfields of AI. These dimensions can be used to characterize different NeSy and StarAI systems. They are concerned with (1) the approach to logical inference, whether model or proof-based; (2) the syntax of the used logical theories; (3) the logical semantics of the systems and their extensions to facilitate learning; (4) the scope of learning, encompassing either parameter or structure learning; (5) the presence of symbolic and subsymbolic representations; (6) the degree to which systems capture the original logic, probabilistic, and neural paradigms; and (7) the classes of learning tasks the systems are applied to. By positioning various NeSy and StarAI systems along these dimensions and pointing out similarities and differences between them, this survey contributes fundamental concepts for understanding the integration of learning and reasoning.","Learning and reasoning; Neurosymbolic AI; Probabilistic logics; Statistical relational AI","en","review","","","","","","","","","","","Algorithmics","","",""
"uuid:c2650bb9-d40c-4b24-9af9-6072fe853b40","http://resolver.tudelft.nl/uuid:c2650bb9-d40c-4b24-9af9-6072fe853b40","Triangulating the future: Developing scenarios of cyclist-automated vehicle interactions from literature, expert perspectives, and survey data","Berge, S.H. (TU Delft Transport and Planning); de Winter, J.C.F. (TU Delft Human-Robot Interaction); Cleij, Diane (SWOV Institute for Road Safety Research); Hagenzieker, Marjan (TU Delft Transport and Planning)","","2024","Automated vehicles pose a unique challenge to the safety of vulnerable road users. Research on cyclist-automated vehicle interaction has received relatively little attention compared to pedestrian safety. This exploratory study aims to bridge this gap by identifying cyclist-automated vehicle scenarios and providing recommendations for future research. In this study, we triangulated three sources: a systematic literature review of previous research on cyclists and automated vehicles, group interviews with eight traffic safety and automation experts, and questionnaire data. The resulting scenario collection comprised 20 prototypical scenarios of cyclist-automated vehicle interaction, grouped into four categories based on the road users’ direction of movement: crossing, passing, overtaking, and merging scenarios. The survey results indicated that right-turning vehicles, dooring scenarios, and more complex situations have the highest likelihood of accidents. Passing and merging scenarios are particularly relevant for studying automated vehicle communication solutions since they involve negotiation. Future research should also consider phantom braking and driving styles of vehicles, as well as programming proactive safety behaviours and designing on-vehicle interfaces that accommodate cyclists.","Automated driving system; Automated vehicle; Bicycle; Cyclist; Methodology; Scenarios; Vulnerable road user","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:ea2d48a7-a455-4ce8-a2a5-632df5764916","http://resolver.tudelft.nl/uuid:ea2d48a7-a455-4ce8-a2a5-632df5764916","Curvature tuning through defect-based 4D printing","Moosabeiki, Vahid (TU Delft Biomaterials & Tissue Biomechanics); Yarali, E. (TU Delft Biomaterials & Tissue Biomechanics); Ghalayaniesfahani, A. (TU Delft Biomaterials & Tissue Biomechanics); Callens, S.J.P. (TU Delft Biomaterials & Tissue Biomechanics); van Manen, T. (TU Delft Support Biomechanical Engineering; TU Delft Biomaterials & Tissue Biomechanics); Accardo, A. (TU Delft Micro and Nano Engineering); Ghodrat, S. (TU Delft Emerging Materials); Bico, José (Sorbonne Université); Habibi, Mehdi (Wageningen University & Research); Mirzaali, Mohammad J. (TU Delft Biomaterials & Tissue Biomechanics); Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics)","","2024","Emerging 4D printing techniques have enabled the realization of smart materials whose shape or properties can change with time. Two important phenomena play important roles in the 4D printing of shape memory polymeric materials. First, the anisotropic deformation of the printed filaments due to residual stresses can be harnessed to create out-of-plane shape transformations. Second, the unavoidable formation of micro-defects during the printing processes often affects the programmability of the printed object. Here, we propose a design approach that harnesses these two effects occurring during fused deposition modeling to create tailor-made curved geometries from initially 2D flat disks. We first determined the size and distribution of the imperfections formed within printed structures by varying two printing parameters namely the printing speed and the number of printed materials. Spatially varying the printing speed and combining polylactic acid filaments with a softer material without shape memory properties allowed us to cover a variety of shapes from negative to positive values of the mean and Gaussian curvature. We propose an analytical model to calculate the magnitude of the maximum out-of-plane deformation from the anisotropic expansion factor of the constituting microstructures. Furthermore, we develop computational models to predict the complex shape-changing of thermally actuated 4D printed structures given the distribution of rationally introduced imperfections and we demonstrate the potential applications of such defect-based metamaterials in drug delivery systems.","OA-Fund TU Delft","en","journal article","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:e9bba975-cea1-488d-9fac-88dbb26f6c8c","http://resolver.tudelft.nl/uuid:e9bba975-cea1-488d-9fac-88dbb26f6c8c","A multiscale consolidation model for press molding of hybrid textiles into complex geometries","Werlen, Vincent (University of Applied Sciences and Arts Northwestern Switzerland; Swiss Federal Institute of Technology); Rytka, Christian (University of Applied Sciences and Arts Northwestern Switzerland); Dransfeld, C.A. (TU Delft Group Dransfeld); Brauner, Christian (University of Applied Sciences and Arts Northwestern Switzerland); Michaud, Véronique (Swiss Federal Institute of Technology)","","2024","Modeling the consolidation of fiber-reinforced thermoplastic composites at the part level presents a formidable computational challenge due to the multi-scale nature of the process. In this article, a method to bypass the multi-scale problem by homogenizing the micro scale and describing the medium with characteristic parameters is described. The model is intended for press molding of hybrid textiles and considers a free-form plate with non-uniform thickness and can describe consolidation in three dimensions with some restrictions. 2D implementation in FEM shows how in-plane matrix pressure gradients can arise in parts and cause fiber disorientation. Experimental verification demonstrates that fiber disorientation arises at the predicted location, and that defect size is proportional to matrix pressure gradient. This novel consolidation model provides new insights, enables part and process optimization, and paves the way for high-quality composite part production. Highlights: A consolidation model for press molding of hybrid textiles is presented. A method to extend consolidation models for complex geometry is presented. The origin of defect formation in complex geometries is explained.","consolidation; defects; fiber-reinforced thermoplastic; finite element analysis (FEA); press molding","en","journal article","","","","","","","","","","","Group Dransfeld","","",""
"uuid:d92ada99-8261-46c1-ac6f-de2e3feb3520","http://resolver.tudelft.nl/uuid:d92ada99-8261-46c1-ac6f-de2e3feb3520","Using sky-classification to improve the short-term prediction of irradiance with sky images and convolutional neural networks","Martinez Lopez, V.A. (TU Delft Photovoltaic Materials and Devices; TU Delft Electrical Engineering, Mathematics and Computer Science); van Urk, G.A. (TU Delft Photovoltaic Materials and Devices; TU Delft Electrical Engineering, Mathematics and Computer Science); Doodkorte, P.J.F. (TU Delft Photovoltaic Materials and Devices; TU Delft Electrical Engineering, Mathematics and Computer Science); Zeman, M. (TU Delft Photovoltaic Materials and Devices); Isabella, O. (TU Delft Photovoltaic Materials and Devices); Ziar, H. (TU Delft Photovoltaic Materials and Devices)","","2024","Clouds moving in front or away from the sun are the leading cause of irradiance variability. These variations have a repercussion on the electricity production of photovoltaic systems. Predicting such changes is essential for proper control of these systems and for maintaining grid stability. Images from the sky have proven to help with short-term solar irradiance forecasting, especially when combined with artificial intelligence. Nevertheless, these models tend to smooth the irradiance fluctuations. We propose a forecasting model to predict the clear-sky index in a forecast horizon of 20 min with a 1-minute resolution. Our model, based on a classifier to determine the sky conditions and, on an optical flow, applies an artificial intelligence model explicitly trained on each class of sky conditions. This strategy has an equivalent performance to an unclassified model and a forecast skill between 5 and 20% with respect to the smart persistence model for most classes of sky conditions while requiring considerably less training data. Although our model reduces the overall predicting error, it still has difficulties predicting irradiance changes and mainly overcast days. Our classifying strategy can be applied to other models targeting different objectives to predict sudden changes in either irradiance or power related to photovoltaic systems.","All-sky images; Deep learning; Irradiance nowcasting; Sky-image processing","en","journal article","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","Photovoltaic Materials and Devices","","",""
"uuid:cdad38c1-baa3-4a0b-94b1-7ef694565f27","http://resolver.tudelft.nl/uuid:cdad38c1-baa3-4a0b-94b1-7ef694565f27","Risk-based optimization of emergency response systems for accidental gas leakage in utility tunnels","Cai, Jitao (China University of Mining and Technology (Beijing)); Wu, Jiansong (China University of Mining and Technology (Beijing)); Yuan, S. (TU Delft Safety and Security Science); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science); Bai, Yiping (China University of Mining and Technology (Beijing))","","2024","Focusing on the effective configuration of emergency response systems in utility tunnels, this study proposes an innovative approach to optimize existing emergency response systems based on a consequence rapid prediction model and genetic algorithm. In the proposed approach, the interactions between different emergency response components are considered to perform a rapid gas dispersion prediction. Furthermore, the predicted gas concentration distribution is employed to estimate the quantitative explosion risks by combining the equivalent cloud method and the Baker-Strehlow model. Finally, the cumulative and cascading risk index are proposed and combined for systematic optimization by using a genetic algorithm. A case study is performed to demonstrate the feasibility of the proposed approach. The results indicate that the optimized emergency response systems effectively reduce both the cumulative and cascading risk level. This study provides technical support for emergency response system design and helps to improve the safety-risk-control capabilities of utility tunnels.","Emergency response system; Natural gas leakage; Quantitative risk assessment; Safety barrier optimization; Utility tunnel","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-21","","","Safety and Security Science","","",""
"uuid:27967d24-6e72-43f1-a4f5-b4ed1d5ea239","http://resolver.tudelft.nl/uuid:27967d24-6e72-43f1-a4f5-b4ed1d5ea239","Coastal adaptation and migration dynamics under future shoreline changes","Tierolf, Lars (Vrije Universiteit Amsterdam); Haer, Toon (Vrije Universiteit Amsterdam); Athanasiou, Panagiotis (Deltares); Luijendijk, Arjen (TU Delft Coastal Engineering; Deltares); Botzen, W. J. Wouter (Vrije Universiteit Amsterdam; Universiteit Utrecht); Aerts, Jeroen C.J.H. (Vrije Universiteit Amsterdam)","","2024","In this study, we present a novel modeling framework that provides a stylized representation of coastal adaptation and migration dynamics under sea level rise (SLR). We develop an agent-based model that simulates household and government agents adapting to shoreline change and increasing coastal flood risk. This model is coupled to a gravity-based model of migration to simulate coastward migration. Household characteristics are derived from local census data from 2015, and household decisions are calibrated based on empirical survey data on household adaptation in France. We integrate projections of shoreline retreat and flood inundation levels under two Representative Concentration Pathways (RCPs) and account for socioeconomic development under two Shared Socioeconomic Pathways (SSPs). The model is then applied to simulate coastal adaptation and migration between 2015 and 2080. Our results indicate that without coastal adaptation, SLR could drive the cumulative net outmigration of 13,100 up to as many as 21,700 coastal inhabitants between 2015 and 2080 under SSP2–RCP4.5 and SSP5–RCP8.5, respectively. This amounts to between 3.0 %–3.7 % of the coastal population residing in the 1/100-year flood zone in 2080 under a scenario of SLR. We find that SLR-induced migration is largely dependent on the adaptation strategies pursued by households and governments. Household implementation of floodproofing measures combined with beach renourishment reduces the projected SLR-induced migration by 31 %–36 % when compared to a migration under a scenario of no adaptation. A sensitivity analysis indicates that the effect of beach renourishment on SLR-induced migration largely depends on the level of coastal flood protection offered by sandy beaches. By explicitly modeling household behavior combined with governmental protection strategies under increasing coastal risks, the framework presented in this study allows for a comparison of climate change impacts on coastal communities under different adaptation strategies.","Agent-based modeling; Climate migration; Coastal adaptation; Coastal erosion; Flood risk; Sea level rise","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:301e837c-8a16-4eb5-bc57-5ef61c28dc81","http://resolver.tudelft.nl/uuid:301e837c-8a16-4eb5-bc57-5ef61c28dc81","The impact of metal centers in the M-MOF-74 series on carbon dioxide and hydrogen separation","Wasik, Dominika O. (Eindhoven University of Technology); Vicent-Luna, José Manuel (Eindhoven University of Technology); Luna-Triguero, Azahara (Eindhoven University of Technology); Dubbeldam, David (Universiteit van Amsterdam); Vlugt, T.J.H. (TU Delft Engineering Thermodynamics); Calero, Sofía (Eindhoven University of Technology)","","2024","The series of metal–organic frameworks M-MOF-74 gained popularity in the field of capture and separation of CO2 due to the presence of numerous, highly reactive open-metal sites. The description of effective interactions between guest molecules and open-metal sites without accounting for polarization effects is challenging but it can significantly reduce the computational cost of simulations. In this study, we propose a non-polarizable force field for CO2, and H2 adsorption in M-MOF-74 (M = Ni, Cu, Co, Fe, Mn, Zn) by scaling the Coulombic interactions of M-MOF-74 atoms, and Lennard-Jones interaction potentials between the center of mass of H2 and the open-metal centers. The presented force field is based on UFF and DREIDING parameters, characterized by high transferability and efficiency. The quantum behavior of H2 at cryogenic temperatures is considered by incorporating Feynman–Hibbs quantum corrections. To validate the force field, the experimental isotherms of CO2 at 298 K and 10−1 – 102kPa, the isotherms of H2 at 77 K and 10−5 – 102kPa, the corresponding enthalpy of adsorption, and the binding geometries in the M-MOF-74 series were reproduced using Monte Carlo simulations in the grand-canonical ensemble. The computed loadings, heats of CO2 and H2 adsorption, and binding geometries in M-MOF-74 are in very good agreement with the experimental values. The temperature transferability of the force field from 77 K to 87 K, and 298 K was shown for adsorption of H2. The validated force field was used to study the adsorption and separation of CO2/H2 mixtures at 298 K. The adsorption of H2 practically does not occur when CO2 is present in the mixture. As indicated from simulated breakthrough curves, the breakthrough time of CO2 in M-MOF-74 follows the same order as the uptake and the heat of CO2 adsorption: Ni ¿ Co ¿ Fe ¿ Mn ¿ Zn ¿ Cu. Increasing the feed mole fraction of CO2 in the breakthrough simulations from 0.1 to 0.9 speeds up the saturation of the adsorbent, leading to a faster exit of CO2 with the column effluent. The application of the non-polarizable force field allows full investigation of the capture and separation of CO2 in M-MOF-74, and can be expanded to study multi-component mixtures or industrial reactions in future research.","Adsorption; Force field; Metal-organic frameworks; Molecular simulations; Monte Carlo","en","journal article","","","","","","","","","","","Engineering Thermodynamics","","",""
"uuid:3cb1ec38-2e11-4947-aafe-f17c8e66740e","http://resolver.tudelft.nl/uuid:3cb1ec38-2e11-4947-aafe-f17c8e66740e","A combined experimental and computational approach to unravel degradation mechanisms in electrochemical wastewater treatment","Feijoo, Sara (Katholieke Universiteit Leuven); Baluchová, S. (TU Delft Micro and Nano Engineering); Kamali, Mohammadreza (Katholieke Universiteit Leuven); Buijnsters, J.G. (TU Delft Micro and Nano Engineering); Dewil, Raf (Katholieke Universiteit Leuven; University of Oxford)","","2024","Electrochemical wastewater treatment is a promising technique to remove recalcitrant pollutants from wastewater. However, the complexity of elucidating the underlying degradation mechanisms hinders its optimisation not only from a techno-economic perspective, as it is desirable to maximise removal efficiencies at low energy and chemical requirements, but also in environmental terms, as the generation of toxic by-products is an ongoing challenge. In this work, we propose a novel combined experimental and computational approach to (i) estimate the contribution of radical and non-radical mechanisms as well as their synergistic effects during electrochemical oxidation and (ii) identify the optimal conditions that promote specific degradation pathways. As a case study, the distribution of the degradation mechanisms involved in the removal of benzoic acid (BA) via boron-doped diamond (BDD) anodes was elucidated and analysed as a function of several operating parameters, i.e., the initial sulfate and nitrate content of the wastewater and the current applied. Subsequently, a multivariate optimisation study was conducted, where the influence of the electrode nature was investigated for two commercial BDD electrodes and a customised silver-decorated BDD electrode. Optimal conditions were identified for each degradation mechanism as well as for the overall BA degradation rate constant. BDD selection was found to be the most influential factor favouring any mechanism (i.e., 52-85% contribution), given that properties such as its boron doping and the presence of electrodeposited silver could dramatically affect the reactions taking place. In particular, decorating the BDD surface with silver microparticles significantly enhanced BA degradation via sulfate radicals, whereas direct oxidation, reactive oxygen species and radical synergistic effects were promoted when using a commercial BDD material with higher boron content and on a silicon substrate. Consequently, by simplifying the identification and quantification of underlying mechanisms, our approach facilitates the elucidation of the most suitable degradation route for a given electrochemical wastewater treatment together with its optimal operating conditions.","","en","journal article","","","","","","","","","","","Micro and Nano Engineering","","",""
"uuid:2f557067-9e37-4271-a499-ce469d51d8fc","http://resolver.tudelft.nl/uuid:2f557067-9e37-4271-a499-ce469d51d8fc","Where the White Continent Is Blue: Deep Learning Locates Bare Ice in Antarctica","Tollenaar, Veronica (Vrije Universiteit Brussel; Swiss Federal Institute of Technology); Zekollari, Harry (Vrije Universiteit Brussel; ETH Zürich; Swiss Federal Institute for Forest, Snow and Landscape Research); Pattyn, Frank (Vrije Universiteit Brussel); Rußwurm, Marc (Swiss Federal Institute of Technology; Wageningen University & Research); Kellenberger, Benjamin (Yale University); Lhermitte, S.L.M. (TU Delft Mathematical Geodesy and Positioning; Katholieke Universiteit Leuven); Izeboud, M. (TU Delft Civil Engineering & Geosciences); Tuia, Devis (Swiss Federal Institute of Technology)","","2024","In some areas of Antarctica, blue-colored bare ice is exposed at the surface. These blue ice areas (BIAs) can trap meteorites or old ice and are vital for understanding the climatic history. By combining multi-sensor remote sensing data (MODIS, RADARSAT-2, and TanDEM-X) in a deep learning framework, we map blue ice across the continent at 200-m resolution. We use a novel methodology for image segmentation with “noisy” labels to learn an underlying “clean” pattern with a neural network. In total, BIAs cover ca. 140,000 km2 (∼1%) of Antarctica, of which nearly 50% located within 20 km of the grounding line. There, the low albedo of blue ice enhances melt-water production and its mapping is crucial for mass balance studies that determine the stability of the ice sheet. Moreover, the map provides input for fieldwork missions and can act as constraint for other geophysical mapping efforts.","Antarctica; blue ice; deep learning; noisy labels","en","journal article","","","","","","","","","Civil Engineering & Geosciences","","Mathematical Geodesy and Positioning","","",""
"uuid:e41eda02-200e-4cdb-9f08-66f4043e4bfe","http://resolver.tudelft.nl/uuid:e41eda02-200e-4cdb-9f08-66f4043e4bfe","Market-orientated solutions to increase thermal conductivity in latent thermal energy storage systems","Righetti, Giulia (Università degli Studi di Padova); Zilio, Claudio (Università degli Studi di Padova); Hooman, K. (TU Delft Heat Transformation Technology); Mancin, Simone (Università degli Studi di Padova)","","2024","Among experts, it is well-known that the thermal conductivity of PCMs (phase change materials) is low hence a major limitation for their commercial application. This work proposes alternative, inexpensive, but nevertheless effective solutions to increase the average thermal conductivity of a PCM system (a commercial paraffin wax, having a phase change temperature of about 40 °C) used for thermal energy storage. 600 g of PCM fills an annulus wrapping an inner tube used to either charge or discharge heat to the PCM. The effect of the flow rate and temperature of the water used as heat transfer fluid was experimentally analysed. The flow rate was set to vary between 2 and 8 l min-1 and the temperature between 45 and 55 °C. We tested three different aluminum-based thermal enhancers: a commercially available metal foam sample, a wire mesh, and irregular flakes (chips) obtained as waste product of machining operations. The PCM-only sample exhibited the longest charging and discharging times, while the PCM + foam sample shortened them the most. The two cost-effective solutions (chip and wire mesh) resulted in intermediate phase change times. A performance indicator, in terms of cost per phase change rate, is proposed to compare different enhancers. It demonstrated that these two cost-effective thermal conductivity enhancing solutions can become a key enabling method to widely deploy latent thermal energy technology widely in many different applications.","Economic solution; Latent thermal energy storage; Metallic chip; Metallic foam; PCM; Thermal conductivity","en","journal article","","","","","","","","","","","Heat Transformation Technology","","",""
"uuid:9ad4f1f3-97df-4c57-a3ce-5a2baa9fff40","http://resolver.tudelft.nl/uuid:9ad4f1f3-97df-4c57-a3ce-5a2baa9fff40","Local Reaction Environment Deviations within Gas Diffusion Electrode Pores for CO2 Electrolysis","Butt, E.N. (TU Delft Complex Fluid Processing); Padding, J.T. (TU Delft Complex Fluid Processing); Hartkamp, Remco (TU Delft Complex Fluid Processing)","","2024","The local conditions inside a gas diffusion electrode (GDE) pore, especially in the electrical double layer (EDL) region, influence the charge transfer reactions and the selectivity of desired CO2ER products. Most GDE computational models ignore the EDL or are limited in their applicability at high potentials. In this work, we present a continuum model to describe the local environment inside a catalytic pore at varying potentials, electrolyte concentrations and pore diameters. The systems studied in this work are based on an Ag catalyst in contact with KHCO3 solution. Our study shows that steric effects dominate the local environment at high cathodic potentials (≪−25 mV vs pzc at the OHP), leading to a radial drop of CO2 concentration. We also observe a drop in pH value within 1 nm of the reaction plane due to electrostatic repulsion and attraction of OH− and H+ ions, respectively. We studied the influence of pore radii (1-10 nm) on electric field and concentrations. Pores with a radius smaller than 5 nm show a higher mean potential, which lowers the mean CO2 concentration. Pores with a favourable local environment can be designed by regulating the ratio between the pore radius and Debye length.","CO electrochemical reduction; gas diffusion electrode; lectric double layer; modelling; steric effects","en","journal article","","","","","","","","","","","Complex Fluid Processing","","",""
"uuid:48e0620e-2ac4-47e5-8a83-3d0d356f2c71","http://resolver.tudelft.nl/uuid:48e0620e-2ac4-47e5-8a83-3d0d356f2c71","Characteristics of ice-structure-soil interaction of an offshore wind turbine","Zou, Pengxu (University of Michigan; CCCC Guangdong-Hong Kong-Macao Greater Bay Area Innovation Research Institute Ltd.); Bricker, J.D. (TU Delft Hydraulic Structures and Flood Risk; University of Michigan); Fujisaki-Manome, Ayumi (University of Michigan); Garcia, Fernando E. (University of Michigan)","","2024","This research investigates the dynamic response of offshore wind turbine (OWT) systems subject to ice-structure-soil interaction (ISSI). To simulate the behavior of level ice sheets, a coupled approach involving the cohesive element method (CEM) and the finite element method (FEM) is applied. For soil-structure interaction (SSI), the Mohr–Coulomb (M-C) model is employed to accommodate glacial soils. A three-dimensional model for ice-OWT-soil interactions is established using LS-DYNA, focusing on the North American Great Lakes region. The impact of factors, including conical structure geometry, ice loading conditions, and soil characteristics, on the actions of ice and the displacement of the OWT structure, is systematically assessed. The results show a notable reduction in horizontal ice forces when a conical structure is used, underscoring its potential to enhance the stability of an OWT. Additionally, lower ice loading height results in increased ice force and reduced structural displacement. Furthermore, variations in soil properties, specifically elastic shear modulus, cohesion and angle of internal friction, exert a significant influence on OWT dynamics. The elastic shear modulus of glacial soils impacts the displacement of the OWT structure, posing a threat to structural stability. In addition, reduced cohesion and friction angle contribute to greater structural displacement.","Conical structures; Dynamic response; Glacial soils; Ice loads; Ice-structure-soil interaction; Offshore wind turbine","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-03","","","Hydraulic Structures and Flood Risk","","",""
"uuid:de7d9d1d-24db-47c5-810d-47b812ea6ee4","http://resolver.tudelft.nl/uuid:de7d9d1d-24db-47c5-810d-47b812ea6ee4","Multi-criteria design methods in façade engineering: State-of-the-art and future trends","Bianchi, S. (TU Delft Architectural Technology); Andriotis, C. (TU Delft Architectural Technology); Klein, T. (TU Delft Architectural Technology); Overend, M. (TU Delft Architectural Technology)","","2024","Façade engineering is facing an era of extraordinary challenge to meet the surge in demand for buildings that are environmentally sustainable and enhance occupant wellbeing. Facades, also known as building envelopes, play a major role in the resource-efficiency of buildings and the quality of its indoor environment. Consequently, the development of effective design approaches is crucial for generating appropriate façade solutions. Façade design is complex and multi-disciplinary involving several and oftentimes conflicting performance criteria. Systematic and holistic design procedures are, therefore, required to achieve optimal trade-offs. Over the last decades, researchers in this field have used computational tools and power to address this challenging problem within the context of multi-criteria design approaches. This paper reviews the existing research in this field, and presents the state-of-the-art review from simple to advanced decision-making procedures currently used at the early design stages, where decisions have a disproportionally large impact on the façade performance. The paper provides a complete description of the design variables and objectives typically involved. Alternative multi-criteria design methodologies regarding discrete decisions and automated optimization are reviewed, each with salient pros/cons, and overall conclusions are drawn. Finally, the paper discusses ongoing trends and research needs, namely, the development of uncertainty-based procedures to enable more informed decision-making; the inclusion of structural/seismic safety considerations in the design process to achieve higher socio-economic benefits; the integration of smart building information modeling and processing technologies to facilitate smarter design decisions; and the adoption of integrated design approaches to promote climate-adaptive solutions that enhance resilience.","Decision-making; Façade design; Multi-criteria; Multi-objective; Optimization; Performance-based","en","review","","","","","","","","","","","Architectural Technology","","",""
"uuid:2f49b47d-d366-420a-8267-6ec3d0ea11e8","http://resolver.tudelft.nl/uuid:2f49b47d-d366-420a-8267-6ec3d0ea11e8","Fifty years after the Schelling's Models of Segregation: Bibliometric analysis of the legacy of Schelling and the future directions of segregation research","Ubareviciene, Ruta (TU Delft Urban Studies; University of Tartu; Lithuanian Centre for Social Sciences); van Ham, M. (TU Delft Urbanism); Tammaru, Tiit (University of Tartu; Estonian Academy of Sciences)","","2024","In 1969 Thomas C. Schelling published his paper “Models of Segregation” and in 1971 he published a follow-up paper introducing “Dynamic Models of Segregation”. Schelling's papers developed the theoretical models of interactive dynamics of individual residential choices, resulting in pronounced patterns of residential segregation at the city level. Even after 50+ years, the topic of residential segregation and sorting remains as relevant as when Schelling published his papers. The two Schelling papers have been cited more than 8000 times together, and have made a strong impact on the residential segregation literature and beyond. In this paper, we examine how Schelling's ideas have impacted empirical research on residential segregation, and thus contributed to a greater understanding of urban processes. We find that few empirical papers explicitly test the Schelling models in residential segregation studies, and there are a growing number of influential papers in the field of segregation that do not reference Schelling. However, the papers by Schelling have served as a source of inspiration for a diverse set of empirical studies, new ways of defining neighbourhoods and developing more comprehensive theories of segregation.","Dynamic models; Preferences; Residential mobility; Schelling; Segregation","en","journal article","","","","","","","","","","Urbanism","Urban Studies","","",""
"uuid:e2ef35ae-6901-4f31-b3bc-c21060e49442","http://resolver.tudelft.nl/uuid:e2ef35ae-6901-4f31-b3bc-c21060e49442","Coupling extracellular glycan composition with metagenomic data in papermill and brewery anaerobic granular sludges","Doloman, Anna (Wageningen University & Research); de Bruin, S. (TU Delft BT/Environmental Biotechnology); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology; Aalborg University); Sousa, Diana Z. (Wageningen University & Research; EWUU Alliance); Lin, Y. (TU Delft BT/Environmental Biotechnology)","","2024","Glycans are crucial for the structure and function of anaerobic granular sludge in wastewater treatment. Yet, there is limited knowledge regarding the microorganisms and biosynthesis pathways responsible for glycan production. In this study, we analysed samples from anaerobic granular sludges treating papermill and brewery wastewater, examining glycans composition and using metagenome-assembled genomes (MAGs) to explore potential biochemical pathways associated with their production. Uronic acids were the predominant constituents of the glycans in extracellular polymeric substances (EPS) produced by the anaerobic granular sludges, comprising up to 60 % of the total polysaccharide content. MAGs affiliated with Anaerolineacae, Methanobacteriaceae and Methanosaetaceae represented the majority of the microbial community (30–50 % of total reads per MAG). Based on the analysis of MAGs, it appears that Anaerolinea sp. and members of the Methanobacteria class are involved in the production of exopolysaccharides within the analysed granular sludges. These findings shed light on the functional roles of microorganisms in glycan production in industrial anaerobic wastewater treatment systems.","Anaerobic granular sludge; EPS biosynthesis pathways; Extracellular polymeric substances; Glycans; Metagenomics","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:ef092c48-9ec2-4657-991b-b51de71f4de8","http://resolver.tudelft.nl/uuid:ef092c48-9ec2-4657-991b-b51de71f4de8","Biosorption of Lead and Copper by Epiphytic Rhizobacterial Species Isolated from Lepironia articulata and Scirpus grossus","Al-Ajalin, Fayeq Abdelhafez (Universiti Kebangsaan Malaysia); Idris, Mushrifah (Universiti Kebangsaan Malaysia); Sheikh Abdullah, Siti Rozaimah (Universiti Kebangsaan Malaysia); Kurniawan, Setyo Budi (Institute of Microbiology of the Academy of Sciences of the Czech Republic); Imron, M.F. (TU Delft Sanitary Engineering; Airlangga University)","","2024","In this study, biosorption potential of nine epiphytic bacteria isolated from the rhizosphere of Lepironia articulata and Scirpus grossus were assessed. Identification of the isolated epiphytic rhizobacteria using 16S rRNA analysis showed species belonging to the four genera of Bacillus, Enterobacter, Aeromonas, and Chromobacterium. Batch biosorption studies were carried out to assess the capacity of the isolated bacteria to act as Pb and Cu biosorbents. Different initial concentrations of the two heavy metals (50, 100, 200, 300, and 400 ppm) were used to determine the ability of the biosorbent to reach a tolerance level and then calculate the percentage of biosorption with respect to 0.1 g dry weight. Initial concentration of Pb and Cu exposed showed that the isolated bacteria have high tolerance up to 400 ppm. Bacteria prefer Pb ions over Cu, which is indicated by higher removal of Pb in all tested reactors. Bacillus sp. (coded Sc1) showed the highest biosorption capacity with 100% Pb and 97% Cu removal.","biosorption; Cu; epiphytic bacteria; Lepironia articulata; Pb; Scirpus grossus","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:2583f9d9-bb42-4a8c-9a3b-5cd47fd5fbd0","http://resolver.tudelft.nl/uuid:2583f9d9-bb42-4a8c-9a3b-5cd47fd5fbd0","DNS and RANS for core-annular flow with a turbulent annulus","Li, H. (TU Delft Fluid Mechanics); Pourquie, M.J.B.M. (TU Delft Fluid Mechanics); Ooms, G. (TU Delft Fluid Mechanics); Henkes, R.A.W.M. (TU Delft Fluid Mechanics)","","2024","DNS and RANS simulations were carried out for core-annular flow in a horizontal pipe and results were compared with experiments carried out with water and oil in our lab. In contrast to most existing studies for core-annular flow available in the literature, the flow annulus is not laminar but turbulent. This makes the simulations more challenging. As DNS does not contain any closure correlations, this approach should give the best representation of the flow (provided a sufficiently accurate numerical mesh and numerical method is used). Various flow configurations were considered, such as without gravity (to enforce an on-average concentric oil core) and with gravity (to allow for eccentricity in the oil core location). Both single-phase and two-phase conditions were considered; single-phase flow refers to the water annulus with imposed wavy wall, whereas two-phase flow includes the determination of the wavy interface. Mesh refinement was carried out to assess the numerical accuracy of the simulation results.","Core-annular flow; Turbulent annulus flow; Two-phase DNS; Wavy interface","en","journal article","","","","","","","","","","","Fluid Mechanics","","",""
"uuid:22824b37-1333-4610-9072-46bb06a172c2","http://resolver.tudelft.nl/uuid:22824b37-1333-4610-9072-46bb06a172c2","A critical assessment and summary on the low carbon energy pile technologies based on the life-cycle perspective: Challenges and prospects","Zhang, Linfeng (Southeast University); Han, Haozhe (The Hong Kong Polytechnic University); Li, Wenxin (Southeast University); Guo, Kewei (Southeast University); Yuan, Minglu (Southeast University); Liu, Zhengxuan (TU Delft Design & Construction Management; Hunan University)","","2024","Energy piles, a technology integrating the heat exchange component within building pile foundations for shallow geothermal energy utilization, have proven economically efficient. They outperform conventional ground source heat pumps by mitigating additional borehole costs and space requirements. This paper systematically examines low-carbon considerations and optimization measures throughout the planning, design, construction, and operation stages of energy piles, considering the entire lifecycle. Furthermore, this paper discusses potential challenges associated with decarbonizing energy piles, offering solutions based on case studies and environmental impact assessments. Through a comprehensive critical review and analysis of existing knowledge, this paper presents a systematic theory and methodology for optimal decarbonization of energy piles, serving as a valuable resource for building practitioners and researchers in this field. The findings not only contribute to a solid theoretical foundation but also provide technical support for the advancement and application of energy pile systems.","Building carbon emissions; Energy piles; Full life-cycle; Low carbonization; Optimize design; Shallow geothermal energy","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-01","","","Design & Construction Management","","",""
"uuid:a4fb1d7a-7ad7-4a7f-a8ad-3a3dd7e20d44","http://resolver.tudelft.nl/uuid:a4fb1d7a-7ad7-4a7f-a8ad-3a3dd7e20d44","Synergetic-informed deep reinforcement learning for sustainable management of transportation networks with large action spaces","Lai, Li (The Hong Kong Polytechnic University); Dong, You (The Hong Kong Polytechnic University); Andriotis, C. (TU Delft Architectural Technology); Wang, Aijun (Wuhan University of Technology); Lei, Xiaoming (The Hong Kong Polytechnic University)","","2024","Effective transportation network management systems should consider safety and sustainability objectives. Existing research on large-scale transportation network management often employs the assumption that bridges can be considered individually under these objectives. However, this simplification misses accurate system-level representations, induced by multiple components, network topology, and global maintenance actions. To address these limitations, this paper presents a deep reinforcement learning (DRL) framework that draws inspiration from biological learning behaviors to determine optimal life-cycle management policies. It incorporates synergetic branches and hierarchical rewards, factorizing the action space and, thereby, diminishing system complexity from exponential to linear with respect to the number of bridges. Extensive experiments based on a realistic case study demonstrate that the proposed method outperforms expert maintenance strategies and state-of-the-art decision-making methods. Overall, the proposed DRL framework can assist engineers by offering adaptive solutions to maintenance planning. It also provides solutions that address large action spaces within complex systems.","deep reinforcement learning; infrastructure management; maintenance optimization; hierarchical reward; life-cycle analysis; large discrete action spaces","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-06","","","Architectural Technology","","",""
"uuid:1cdcb884-5936-41cc-a213-60985b962e3a","http://resolver.tudelft.nl/uuid:1cdcb884-5936-41cc-a213-60985b962e3a","Effect of temperature on the healing capacity and mechanical properties of Ti2AlC MAX phase ceramics","Suh, Minji (Kookmin University); Lee, Dong Heon (Kookmin University); Sloof, W.G. (TU Delft Team Joris Dik); Lee, Kee Sung (Kookmin University)","","2024","In this study, the self-healing capacity of Titanium Aluminum Carbide (Ti2AlC, MAX phase) was investigated. Bulk coin samples were fabricated to evaluate the self-healing capacity at different temperatures (1000, 1200, and 1400°C). The extensive self-healing capacity of Ti2AlC was confirmed on larger quasiplastic damage (diameter ≥1 mm) and radial cracks by covering and filling of oxides such as titanium oxide, aluminum oxide, and aluminum titanate oxide. Although the mechanical properties of Ti2AlC after healing are similar or improved relative to the Ti2AlC before healing at the microscale, some properties of Ti2AlC after introducing larger damage and healing at 1400°C showed reduced values due to excessive oxide formation on the surface. For example, the strength of Ti2AlC healed at 1400°C exhibited 151.4 MPa, which is relative to the original strength of 298.3 MPa. Alternatively, the mechanical properties such as strength, hardness, toughness, and relative modulus of elasticity of Ti2AlC healed at 1000 or 1200°C and were restored to their original strength after healing. These findings suggest that Ti2AlC can be used as a healing agent for high-temperature applications, such as environmental barrier coating for gas turbine hot-gas components.","cracks/cracking; damage healing; indentation; MAX phase; mechanical properties","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-07","","","Team Joris Dik","","",""
"uuid:bb8babdc-8861-4257-8185-6ad4b50287b0","http://resolver.tudelft.nl/uuid:bb8babdc-8861-4257-8185-6ad4b50287b0","4D printed shape-shifting biomaterials for tissue engineering and regenerative medicine applications","Kalogeropoulou, Maria (Student TU Delft); Diaz Payno, P.J. (TU Delft Biomaterials & Tissue Biomechanics; Erasmus MC); Mirzaali, Mohammad J. (TU Delft Biomaterials & Tissue Biomechanics); van Osch, G.J.V.M. (TU Delft Biomaterials & Tissue Biomechanics; Erasmus MC); Fratila-Apachitei, E.L. (TU Delft Biomaterials & Tissue Biomechanics); Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics; Leiden University Medical Center)","","2024","The existing 3D printing methods exhibit certain fabrication-dependent limitations for printing curved constructs that are relevant for many tissues. Four-dimensional (4D) printing is an emerging technology that is expected to revolutionize the field of tissue engineering and regenerative medicine (TERM). 4D printing is based on 3D printing, featuring the introduction of time as the fourth dimension, in which there is a transition from a 3D printed scaffold to a new, distinct, and stable state, upon the application of one or more stimuli. Here, we present an overview of the current developments of the 4D printing technology for TERM, with a focus on approaches to achieve temporal changes of the shape of the printed constructs that would enable biofabrication of highly complex structures. To this aim, the printing methods, types of stimuli, shape-shifting mechanisms, and cell-incorporation strategies are critically reviewed. Furthermore, the challenges of this very recent biofabrication technology as well as the future research directions are discussed. Our findings show that the most common printing methods so far are stereolithography (SLA) and extrusion bioprinting, followed by fused deposition modelling, while the shape-shifting mechanisms used for TERM applications are shape-memory and differential swelling for 4D printing and 4D bioprinting, respectively. For shape-memory mechanism, there is a high prevalence of synthetic materials, such as polylactic acid (PLA), poly(glycerol dodecanoate) acrylate (PGDA), or polyurethanes. On the other hand, different acrylate combinations of alginate, hyaluronan, or gelatin have been used for differential swelling-based 4D transformations. TERM applications include bone, vascular, and cardiac tissues as the main target of the 4D (bio)printing technology. The field has great potential for further development by considering the combination of multiple stimuli, the use of a wider range of 4D techniques, and the implementation of computational-assisted strategies.","3D printing; regenerative medicine; shape-change transformation; shape-shifting; smart materials; stimuli-responsive","en","review","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:a8fceeff-cc9c-4159-b1e8-51fbc9f776c0","http://resolver.tudelft.nl/uuid:a8fceeff-cc9c-4159-b1e8-51fbc9f776c0","School-Based Interventions for Increasing Autistic Pupils’ Social Inclusion in Mainstream Schools: A Systematic Review","Tsou, Yung-Ting (Universiteit Leiden; Vrije Universiteit Amsterdam); Kovács, Lilla Veronika (Universiteit Leiden); Louloumari, Angeliki (Universiteit Leiden); Stockmann, Lex (Universiteit Leiden); Blijd-Hoogewys, Els M.A. (INTER-PSY; Rijksuniversiteit Groningen); Koutamanis, A. (TU Delft Design & Construction Management); Rieffe, Carolien (Universiteit Leiden; University of Twente; University College London (UCL))","","2024","School-based interventions for socially including autistic pupils in mainstream schools were systematically reviewed. Included interventions targeted at least one level of the school environment: the autistic children, the peers, the staff, and/or the physical environment, and assessed autistic pupils’ quantity and/or quality of social participation as outcome measures. Findings from 56 studies showed increased accessibility of school activities to autistic pupils, but the reciprocity and friendship between the autistic pupils and the peers were not necessarily improved. Moreover, limited interventions were available for modifying the physical environment. A more holistic strategy that moves the focus from individual children’s social skills to the larger context surrounding children, should be considered for a better inclusion of autistic children in school routine.","Autism; Mainstream Schools; School-Based Intervention; Social Inclusion; Systematic Review","en","review","","","","","","","","","","","Design & Construction Management","","",""
"uuid:cc82e749-c767-4199-8939-91cfba1d553c","http://resolver.tudelft.nl/uuid:cc82e749-c767-4199-8939-91cfba1d553c","The challenges of high-quality development in Chinese secondary cities: A typological exploration","Du, Y. (TU Delft Spatial Planning and Strategy); Viseu Cardoso, Rodrigo (TU Delft Spatial Planning and Strategy); Rocco, Roberto (TU Delft Spatial Planning and Strategy)","","2024","The governmental initiative of high-quality development (HQD) marks a shift in the Chinese development paradigm from prioritizing speed to prioritizing quality towards comprehensive goals of economic growth, social vitality, innovation capacity, industrial upgrading, regional cooperation, and green transformation. This initiative is increasingly discussed within the framework of mega-regions, with prior studies demonstrating that they are critical arenas for promoting HQD visions. However, unevenness within mega-regions has become an important limitation to this vision. Namely, significant disparities exist between mega-regional core cities and the smaller neighboring cities in most HQD indicators. This paper conceptualizes these smaller players as secondary cities. Based on this, this paper aims to understand and differentiate the specific challenges of secondary cities facing intra-regional unevenness in the context of HQD. We build an evaluation framework and employ the TOPSIS method to evaluate 34 core cities and 180 secondary cities. Then, we introduce typological thinking to develop a meaningful classification of secondary cities based on the results of these evaluations. K-means clustering analysis identifies five secondary city types with similar profiles. The analysis supports the discussion of the characteristics and challenges of each type and may contribute to policy recommendations for a balanced HQD in mega-regional secondary cities.","High-quality development; Intra-regional unevenness; K-means clustering analysis; Mega-regional secondary city; TOPSIS; Typological analysis","en","journal article","","","","","","","","","","","Spatial Planning and Strategy","","",""
"uuid:50589613-835a-457b-8219-84b04f77e5eb","http://resolver.tudelft.nl/uuid:50589613-835a-457b-8219-84b04f77e5eb","Spike sorting in the presence of stimulation artifacts: a dynamical control systems approach","Shokri, M. (TU Delft Team Tamas Keviczky); Gogliettino, Alex R. (Stanford University); Hottowy, Paweł (AGH University of Science and Technology); Sher, Alexander (University of California); Litke, Alan M. (University of California); Chichilnisky, E. J. (Stanford University); Pequito, Sérgio (Uppsala University); Muratore, D.G. (TU Delft Bio-Electronics)","","2024","Objective. Bi-directional electronic neural interfaces, capable of both electrical recording and stimulation, communicate with the nervous system to permit precise calibration of electrical inputs by capturing the evoked neural responses. However, one significant challenge is that stimulation artifacts often mask the actual neural signals. To address this issue, we introduce a novel approach that employs dynamical control systems to detect and decipher electrically evoked neural activity despite the presence of electrical artifacts. Approach. Our proposed method leverages the unique spatiotemporal patterns of neural activity and electrical artifacts to distinguish and identify individual neural spikes. We designed distinctive dynamical models for both the stimulation artifact and each neuron observed during spontaneous neural activity. We can estimate which neurons were active by analyzing the recorded voltage responses across multiple electrodes post-stimulation. This technique also allows us to exclude signals from electrodes heavily affected by stimulation artifacts, such as the stimulating electrode itself, yet still accurately differentiate between evoked spikes and electrical artifacts. Main results. We applied our method to high-density multi-electrode recordings from the primate retina in an ex vivo setup, using a grid of 512 electrodes. Through repeated electrical stimulations at varying amplitudes, we were able to construct activation curves for each neuron. The curves obtained with our method closely resembled those derived from manual spike sorting. Additionally, the stimulation thresholds we estimated strongly agreed with those determined through manual analysis, demonstrating high reliability ( R 2 = 0.951 for human 1 and R 2 = 0.944 for human 2). Significance. Our method can effectively separate evoked neural spikes from stimulation artifacts by exploiting the distinct spatiotemporal propagation patterns captured by a dense, large-scale multi-electrode array. This technique holds promise for future applications in real-time closed-loop stimulation systems and for managing multi-channel stimulation strategies.","Bi-directional neural interface; dynamical control systems; spike sorting; stimulation artifact","en","journal article","","","","","","","","","","","Team Tamas Keviczky","","",""
"uuid:678c1b29-f517-4918-9980-75cbb9677548","http://resolver.tudelft.nl/uuid:678c1b29-f517-4918-9980-75cbb9677548","Aortic valve neocuspidization and bioprosthetic valves: Evaluating turbulence haemodynamics","Manchester, Emily Louise (Imperial College London; The University of Manchester); Pirola, S. (TU Delft Medical Instruments & Bio-Inspired Technology; Imperial College London); Pirola, Sergio (IRCCS Centro Cardiologico Monzino); Mastroiacovo, Giorgio (IRCCS Centro Cardiologico Monzino); Polvani, Gianluca (IRCCS Centro Cardiologico Monzino; University of Milan); Pontone, Gianluca (University of Milan; IRCCS Centro Cardiologico Monzino); Xu, Xiao Yun (Imperial College London)","","2024","Aortic valve disease is often treated with bioprosthetic valves. An alternative treatment is aortic valve neocuspidization which is a relatively new reparative procedure whereby the three aortic cusps are replaced with patient pericardium or bovine tissues. Recent research indicates that aortic blood flow is disturbed, and turbulence effects have yet to be evaluated in either bioprosthetic or aortic valve neocuspidization valve types in patient-specific settings. The aim of this study is to better understand turbulence production in the aorta and evaluate its effects on laminar and turbulent wall shear stress. Four patients with aortic valve disease were treated with either bioprosthetic valves (n=2) or aortic valve neocuspidization valvular repair (n=2). Aortic geometries were segmented from magnetic resonance images (MRI), and 4D flow MRI was used to derive physiological inlet and outlet boundary conditions. Pulsatile large-eddy simulations were performed to capture the full range of laminar, transitional and turbulence characteristics in the aorta. Turbulence was produced in all aortas with highest levels occurring during systolic deceleration. In the ascending aorta, turbulence production is attributed to a combination of valvular skew, valvular eccentricity, and ascending aortic dilation. In the proximal descending thoracic aorta, turbulence production is dependent on the type of arch-descending aorta connection (e.g., a narrowing or sharp bend) which induces flow separation. Laminar and turbulent wall shear stresses are of similar magnitude throughout late systolic deceleration and diastole, although turbulent wall shear stress magnitudes exceed laminar wall shear stresses between 27.3% and 61.1% of the cardiac cycle. This emphasises the significance of including turbulent wall shear stress to improve our comprehension of progressive arterial wall diseases. The findings of this study recommend that aortic valve treatments should prioritise minimising valvular eccentricity and skew in order to mitigate turbulence generation.","Aortic valve neocuspidization; Aortic valve replacement; Bioprosthesis; Blood flow; Computational fluid dynamics; Haemodynamics; Large-eddy simulation; Ozaki procedure; Turbulence; Wall shear stress","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:267d8ed2-4aa9-4ecc-b250-7b6321136419","http://resolver.tudelft.nl/uuid:267d8ed2-4aa9-4ecc-b250-7b6321136419","Incorporating Safety-II in future gas systems","Riemersma, B. (TU Delft Economics of Technology and Innovation); Correljé, A. (TU Delft Economics of Technology and Innovation); Kunneke, R.W. (TU Delft Economics of Technology and Innovation)","","2024","This article studies safety management in future gas systems. It is structured around the compatibility of its technological and institutional coordination. We identify how the current mode of safety management is not in harmony with increasingly complex technological and institutional arrangements, and combine safety science with institutional analysis to improve safety management. For our case study of biogas quality monitoring in the Netherlands, we offer structured recommendations for the reallocation of monitoring and enforcement mechanisms based on Safety-II. This article provides insights for users of gas systems and other infrastructures alike, and it offers safety scholars an approach to safety management that incorporates a novel focus on institutions.","Alignment Framework; Complex Systems; Institutional Analysis; Renewable Energy Systems; Safety Management; Safety-II","en","journal article","","","","","","","","","","","Economics of Technology and Innovation","","",""
"uuid:00a22e9b-308f-4b83-8cbd-213529211d58","http://resolver.tudelft.nl/uuid:00a22e9b-308f-4b83-8cbd-213529211d58","Lower limb biomechanics of fully trained exoskeleton users reveal complex mechanisms behind the reductions in energy cost with human-in-the-loop optimization","Poggensee, K. (TU Delft Human-Robot Interaction; Erasmus MC; Stanford University); Collins, Steven H. (Stanford University)","","2024","Exoskeletons that assist in ankle plantarflexion can improve energy economy in locomotion. Characterizing the joint-level mechanisms behind these reductions in energy cost can lead to a better understanding of how people interact with these devices, as well as to improved device design and training protocols. We examined the biomechanical responses to exoskeleton assistance in exoskeleton users trained with a lengthened protocol. Kinematics at unassisted joints were generally unchanged by assistance, which has been observed in other ankle exoskeleton studies. Peak plantarflexion angle increased with plantarflexion assistance, which led to increased total and biological mechanical power despite decreases in biological joint torque and whole-body net metabolic energy cost. Ankle plantarflexor activity also decreased with assistance. Muscles that act about unassisted joints also increased activity for large levels of assistance, and this response should be investigated over long-term use to prevent overuse injuries.","biomechanics; exoskeletons; gait; human-in-the-loop optimization; plantarflexion assistance","en","journal article","","","","","","","","","","","Human-Robot Interaction","","",""
"uuid:e4badb9a-3515-45eb-8b31-6b7d0a4f1a29","http://resolver.tudelft.nl/uuid:e4badb9a-3515-45eb-8b31-6b7d0a4f1a29","Depth estimation in SPAD-based LIDAR sensors","Chen, Mingzhe (Student TU Delft; Silicon Integrated B.V.); Ramachandra Rao, P. (TU Delft Electronic Instrumentation); Venialgo Araujo, E. (TU Delft Optical Technologies)","","2024","In direct time-of-flight (D-TOF) light detection and ranging (LIDAR), accuracy and full-scale range (FSR) are the main performance parameters to consider. Particularly, in single-photon avalanche diodes (SPAD) based systems, the photon-counting statistics plays a fundamental role in determining the LIDAR performance. Also, the intrinsic performance ultimately depends on the system parameters and constraints, which are set by the application. However, the best-achievable performance directly depends on the selected depth estimation method and is not necessarily equal to intrinsic performance. We evaluate a D-TOF LIDAR system, in the particular context of smartphone applications, in terms of parameter trade-offs and estimation efficiency. First, we develop a simulation model by combining radiometry and photon-counting statistics. Next, we perform a trade-off analysis to study dependencies between system parameters and application constraints, as well as non-linearities caused by the detection method. Further, we derive an analytical model to calculate the Cramér–Rao lower bound (CRLB) of the LIDAR system, which analytically accounts for the shot noise. Finally, we evaluate a depth estimation method based on artificial intelligence (AI) and compare its performance to the CRLB. We demonstrate that the AI-based estimator fully compensates the non-linearity in depth estimation, which varies depending on application conditions such as target reflectivity.","","en","journal article","","","","","","","","","","","Electronic Instrumentation","","",""
"uuid:b5cdcf7f-b665-4806-b1e2-69c7d4420bdc","http://resolver.tudelft.nl/uuid:b5cdcf7f-b665-4806-b1e2-69c7d4420bdc","Snapshot GNSS receivers for low-effort, high-gain space situational awareness","Gill, E.K.A. (TU Delft Space Systems Egineering); Akos, D. M. (University of Colorado)","","2024","This paper proposes a novel concept of using highly efficient Snapshot Global Navigation Satellite Systems (GNSS) receivers to provide precise position fixes of single or multiple satellites in Low-Earth Orbit (LEO) to improve upper atmospheric modeling and thus contribute to superior space situational awareness (SSA). While tracking of LEO satellites and the use of onboard GNSS receivers for drag measurements and upper atmosphere modeling are well-established techniques, the expected advent of snapshot GNSS receivers for spaceborne scientific applications will allow massive improvements on the GNSS sensor's Size, Weight, Power and Cost (SWaP-C). With chip-size dimensions of 4x4 mm2, a mass of less than 5 gr, an average power level below 0.1 mW, snapshot receiver technology is expected to provide position fixes in space with an accuracy of ∼19 m (3D r.m.s.), which will surpass the accuracy of Two-Line Elements (TLE) provided by the US Joint Space Operations Center (JSpOC) by at least two orders of magnitude. Equally important to their SWaP-C benefits, Snapshot GNSS receivers will allow mission and spacecraft designers to trade onboard-processing requirements versus payload downlink requirements, leading to either minimum onboard processing or a minimum amount of downlinked data. In this research, we establish the concept and architectural overview of using snapshot GNSS receivers for SSA, including the role of using them in a Distributed Space System (DSS), and detail their characterization and performance in terms of the required GNSS hardware and the impact of these payload on the power budget, the link budget and the OnBoard Data Handling (OBDH) budget of a satellite. It will be shown that these receivers lend themselves especially to their use on femto-, pico- and nano-satellites, although integrated snapshot modules may be flown as auxiliary payloads on micro- or mini-satellites as well. While this work focuses on the implications of the use of snapshot GNSS receivers on spacecraft design for the use of upper atmosphere modeling and SSA, their use may open up other science applications which avoid the need for expensive high-grade GNSS receivers.","Atmospheric drag; GNSS receiver; Snapshot receiver; Space Situational Awareness; Upper atmosphere density modeling","en","journal article","","","","","","","","","","","Space Systems Egineering","","",""
"uuid:b0b138da-8ca2-411c-9648-be5f6dde6a6f","http://resolver.tudelft.nl/uuid:b0b138da-8ca2-411c-9648-be5f6dde6a6f","Predictive simulations identify potential neuromuscular contributors to idiopathic toe walking","Veerkamp, Kirsten (Vrije Universiteit Amsterdam; Griffith University; Amsterdam Movement Sciences, Rehabilitation & Development); van der Krogt, Marjolein M. (Vrije Universiteit Amsterdam; Amsterdam Movement Sciences, Rehabilitation & Development); Waterval, Niels F.J. (Vrije Universiteit Amsterdam; Universiteit van Amsterdam; Amsterdam Movement Sciences, Rehabilitation & Development); Geijtenbeek, T. (TU Delft Biomechatronics & Human-Machine Control); Walsh, H. P.John (Griffith University; Queensland Children's Hospital); Harlaar, J. (TU Delft Biomechatronics & Human-Machine Control; Erasmus MC); Buizer, Annemieke I. (Vrije Universiteit Amsterdam; Emma Children's Hospital Academic Medical Center, University of Amsterdam; Amsterdam Movement Sciences, Rehabilitation & Development); Lloyd, David G. (Griffith University); Carty, Christopher P. (Griffith University; Queensland Children's Hospital)","","2024","Background: Most cases of toe walking in children are idiopathic. We used pathology-specific neuromusculoskeletal predictive simulations to identify potential underlying neural and muscular mechanisms contributing to idiopathic toe walking. Methods: A musculotendon contracture was added to the ankle plantarflexors of a generic musculoskeletal model to represent a pathology-specific contracture model, matching the reduced ankle dorsiflexion range-of-motion in a cohort of children with idiopathic toe walking. This model was employed in a forward dynamic simulation controlled by reflexes and supraspinal drive, governed by a multi-objective cost function to predict gait patterns with the contracture model. We validated the predicted gait using experimental gait data from children with idiopathic toe walking with ankle contracture, by calculating the root mean square errors averaged over all biomechanical variables. Findings: A predictive simulation with the pathology-specific model with contracture approached experimental ITW data (root mean square error = 1.37SD). Gastrocnemius activation was doubled from typical gait simulations, but lacked a peak in early stance as present in electromyography. This synthesised idiopathic toe walking was more costly for all cost function criteria than typical gait simulation. Also, it employed a different neural control strategy, with increased length- and velocity-based reflex gains to the plantarflexors in early stance and swing than typical gait simulations. Interpretation: The simulations provide insights into how a musculotendon contracture combined with altered neural control could contribute to idiopathic toe walking. Insights into these neuromuscular mechanisms could guide future computational and experimental studies to gain improved insight into the cause of idiopathic toe walking.","Forward dynamics; Neural control; Neuromusculoskeletal modelling; OpenSim; Paediatrics","en","journal article","","","","","","","","","","","Biomechatronics & Human-Machine Control","","",""
"uuid:1f6349f3-4447-46b4-bcd5-9e1dea1d3fb3","http://resolver.tudelft.nl/uuid:1f6349f3-4447-46b4-bcd5-9e1dea1d3fb3","Characterizing nature-based living labs from their seeds in the past","Bhatta, A. (TU Delft Multi Actor Systems; TU Delft Policy Analysis; Deltares); Vreugdenhil, H.S.I. (TU Delft Multi Actor Systems; TU Delft Policy Analysis; Deltares); Slinger, J (TU Delft Multi Actor Systems; TU Delft Policy Analysis; Rhodes University)","","2024","Nature-based living labs combine the elements of nature-based solution design with a living lab context to address social and environmental resilience challenges. There is a need to deepen insights on the characteristics of the emergent phenomenon of nature-based living labs, with respect to their predecessors. Accordingly, the paper first develops an outline of how living labs evolved into nature-based living labs, informed by bibliometric analysis. Second, the unique characteristics of nature-based living labs are identified using a systematic literature review. Finally, the core characteristics of living labs are determined, and nature-based living labs are placed within this context. Initial living labs had a strong technological focus, which proliferated into diverse application domains and regions after the European Network of Living Labs was established and expanded. Urban living labs emerged as a significant multidisciplinary and geographically specific domain, while nature-based living labs are inherently sustainability-oriented and consider ecosystem processes, interactions, and natural materials. Next, the paper identifies nine characteristics of nature-based living labs, five of which are always present, namely: (i) real-life spatial context and multi-scale, (ii) innovation and learning, (iii) user-centric, (iv) multi-actor involvement and (v) sustainability-oriented multiple benefits. Then, the four core characteristics of living labs, the variation within these characteristics, and how these align with the characteristics of nature-based living labs are clarified. Finally, the need for research on living labs across application domains and regions is highlighted, so that the global applicability of these local, user-centric, innovative approaches can be established.","Living labs; Nature-based solutions; Real-life setting; Stakeholder participation; User-centric innovation","en","review","","","","","","","","","","Multi Actor Systems","Policy Analysis","","",""
"uuid:1867c1ac-4b45-4b08-b909-74f85f903556","http://resolver.tudelft.nl/uuid:1867c1ac-4b45-4b08-b909-74f85f903556","Assessment of immersed boundary methods for hypersonic flows with gas–surface interactions","Başkaya, A.O. (TU Delft Aerodynamics); Capriati, Michele (von Karman Institute for Fluid Dynamics; Institut National de Recherche en Informatique et en Automatique (INRIA)); Turchi, Alessandro (von Karman Institute for Fluid Dynamics; Italian Space Agency); Magin, Thierry (von Karman Institute for Fluid Dynamics); Hickel, S. (TU Delft Aerodynamics)","","2024","The efficacy of immersed boundary (IB) methods with adaptive mesh refinement (AMR) techniques is assessed in the context of atmospheric entry applications, including effects of chemical nonequilibrium (CNE) and gas–surface interactions (GSI). We scrutinize a conservative cut-cell IB method and two non-conservative IB methods, comparing their results with analytical solutions, data from the literature, and results obtained with a reference solver that operates on body-fitted grids. All solvers employ the same external thermochemistry library, ensuring that all observed differences can be attributed solely to differences in the underlying numerical methodologies. We present results for eight benchmark cases. Four verification cases verify the implementation of chemistry, transport properties, catalytic boundary conditions, and shock capturing. Four validation cases encompass blunt geometries with adiabatic and isothermal, as well as inert, catalytic and ablative boundary conditions. Overall, the results obtained with the IB solvers are in very good agreement with the reference data. Discrepancies arise in cases with large temperature or concentration gradients at the wall, and these are linked to conservation errors inherent to ghost-cell and interpolation-based IB methods. Only a strictly conservative cut-cell IB method is on par with body-fitted grid methods.","Ablation; Atmospheric entry; Gas–surface interaction; Hypersonic flow; Immersed boundary method; Mass conservation","en","journal article","","","","","","","","","","","Aerodynamics","","",""
"uuid:757846e0-68e3-4a52-a8c9-0b9a842af5a4","http://resolver.tudelft.nl/uuid:757846e0-68e3-4a52-a8c9-0b9a842af5a4","Photoactivity of amorphous and crystalline TiO2 nanotube arrays (TNA) films in gas phase CO2 reduction to methane with simultaneous H2 production","Santos, Janaina S. (Chulalongkorn University); Fereidooni, Mohammad (Chulalongkorn University); Márquez, Victor (Chulalongkorn University); Paz-López, Christian V. (Chulalongkorn University); Villanueva, Martin S. (Benemerita Universidad Autonoma de Puebla); Buijnsters, J.G. (TU Delft Micro and Nano Engineering); Praserthdam, Supareak (Chulalongkorn University); Praserthdam, Piyasan (Chulalongkorn University)","","2024","This study assessed the photoactivity of amorphous and crystalline TiO2 nanotube arrays (TNA) films in gas phase CO2 reduction. The TNA photocatalysts were fabricated by titanium anodization and submitted to an annealing treatment for crystallization and/or cathodic reduction to introduce Ti3+ and oxygen vacancies into the TiO2 structure. The cathodic reduction demonstrated a significant effect on the generated photocurrent. The photoactivity of the four TNA catalysts in CO2 reduction with water vapor was evaluated under UV irradiation for 3 h, where CH4 and H2 were detected as products. The annealed sample exhibited the best performance towards methane with a production rate of 78 μmol gcat−1 h−1, followed by the amorphous film, which also exhibited an impressive formation rate of 64 μmol gcat−1 h−1. The amorphous and reduced-amorphous films exhibited outstanding photoactivity regarding H2 production (142 and 144 μmol gcat−1 h−1, respectively). The annealed catalyst also revealed a good performance for H2 production (132 μmol gcat−1 h−1) and high stability up to five reaction cycles. Molecular dynamic simulations demonstrated the changes in the band structure by introducing oxygen vacancies. The topics covered in this study contribute to the Sustainable Development Goals (SDG), involving affordable and clean energy (SDG#7) and industry, innovation, and infrastructure (SDG#9).","Amorphous titania; Anatase; CO photoreduction; Hydrogen generation; Methane; TiO nanotubes","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-15","","","Micro and Nano Engineering","","",""
"uuid:6c694458-9dc3-4af8-a7fb-84fac856cd78","http://resolver.tudelft.nl/uuid:6c694458-9dc3-4af8-a7fb-84fac856cd78","Performance assessment of an eco-friendly tandem solar cell based on double perovskite Cs2AgBiBr6","Chrafih, Younes (Mohammed V University); Al-Hattab, Mohamed (Sultan Moulay Slimane University); El Boubekri, A. (Sultan Moulay Slimane University); Rahmani, Khalid (Ecole Normale Supérieure (ENS), Mohammed V University); Bajjou, Omar (Sultan Moulay Slimane University); Basyooni, Mohamed A. (TU Delft Dynamics of Micro and Nano Systems; Selçuk University)","","2024","Tandem solar cells have a wider photon absorption range, allowing them to provide better efficiency than single-junction SC. The upper cell absorbs high-energy photons, while the lower cell absorbs low-energy filtered photons. However, in order to obtain affordable, efficient, and long-lasting SC, the absorber layers of the top and bottom cells must be integrated with an adequate bandgap. This research suggests tandem perovskite solar cells as upper band active materials in this setting. The Si homojunction solar cell's performance was improved by investigating the thicknesses of the p−type and n−type layers, doping concentrations, and defect densities. The thickness variation of the perovskite solar cell (100−400nm) is then optimized. To precisely replicate the tandem devices, the estimated spectra of the perovskite SC are optically filtered onto the lower cells. Current matching was achieved by adjusting the thickness of the perovskite sub-cell with different bottom layer thicknesses, and the optimized efficiency of 36.26% for the perovskite/Si tandem device was shown. The discoveries will open the door for the upcoming creation of high−efficiency, low-energy solar cells.","CsAgBiBr; DFT; Scaps-1d; Solar cell; Tandem solar cell","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-15","","","Dynamics of Micro and Nano Systems","","",""
"uuid:a516a861-d8b0-47c6-979a-235378ed0587","http://resolver.tudelft.nl/uuid:a516a861-d8b0-47c6-979a-235378ed0587","A directional coupler for partial discharge measurements in gas-insulated substations","Mier Escurra, C. (TU Delft High Voltage Technology Group); Mor, A. R. (Universitat Politécnica de Valencia); Vaessen, P.T.M. (TU Delft High Voltage Technology Group)","","2024","This paper introduces a directional coupler for partial discharge (PD) measurements in gas-insulated substations (GIS). The sensor comprises a combination of magnetic and electric couplers, effectively segregating forward and backward pulses to enhance PD charge estimation and defect location. The sensor's design was supported with finite element method simulations and measurements conducted in a transverse electromagnetic test bench. Comparative analyses were performed against independent magnetic and electric couplers. The charge estimation and the directional coupler's directivity were evaluated in both the test bench and a full-scale GIS with different PD defects. Initially, the combined magnetic and the electric couplers exhibited undesired interactions, prompting corrective measures. Subsequent adjustments included changes to the electric coupler material and modifications to the magnetic coupler construction. The resulting high-voltage directional coupler performed better than the separated couplers in a GIS with discontinuities. This partial discharge sensor emerges as a candidate for future SF6-free alternative GIS.","Calibration; Directional coupler; Gas-insulated; Partial discharges; PD sensors","en","journal article","","","","","","","","","","","High Voltage Technology Group","","",""
"uuid:e2fbd8b6-2a09-4eba-afaa-f5a3126b59f5","http://resolver.tudelft.nl/uuid:e2fbd8b6-2a09-4eba-afaa-f5a3126b59f5","High-resolution turbofan intake flow characterization by automated stereoscopic-PIV in an industrial wind tunnel environment","Ujjaini Kempaiah, K. (TU Delft Aerodynamics; LaVision); Piovesan, Tommaso (Cranfield University); Zachos, Pavlos K. (Cranfield University); Michaelis, Dirk (LaVision); Gebbink, Roy (German-Dutch Wind Tunnels); van Rooijen, Bart (German-Dutch Wind Tunnels); Prieto, Daniel Gil (Rolls-Royce plc); MacManus, David (Cranfield University); Sciacchitano, A. (TU Delft Aerodynamics); Sheaf, Christopher (Rolls-Royce plc)","","2024","Unsteady inlet flow distortion can influence the stability and performance of any propulsion system, in particular for more novel, short and slim intakes of future aero-engine configurations. As such, the requirement for measurement methods able to provide high spatial resolution data is important to aid the understanding of these flow fields. This work presents flow field characterisations at a crossflow plane within a short aeroengine intake using stereoscopic particle image velocimetry (SPIV). A series of tests were conducted across a range of crosswind and high angle of attack conditions for a representative short and slim aspirated intake configuration at two operating points in terms of mass flow rate. The velocity maps were measured at a crossflow plane within the intake at an axial position L/D = 0.058 from where a fan is expected to be installed. The diameter of the measurement plane was 250 mm, and the final spatial resolution of the velocity fields had a vector pitch of 1.5 mm which is at least two orders of magnitude richer than conventional pressure-based distortion measurements. The work demonstrates the ability to perform robust non-intrusive flow measurements within modern intake systems in an industrial wind tunnel environment across a wide range of operating conditions; hence, it is suggested that SPIV can potentially become part of standard industrial testing. The results provide rich datasets that can notably improve our understanding of unsteady distortions and influence the design of novel, closely coupled engine-intake systems.","industrial wind tunnel testing; inlet distortion; inlet testing; non-intrusive measurements; particle image velocimetry; turbofan; ultra high bypass ration engines","en","journal article","","","","","","","","","","","Aerodynamics","","",""
"uuid:39016597-6bf1-4636-89c2-96cf9cf1707e","http://resolver.tudelft.nl/uuid:39016597-6bf1-4636-89c2-96cf9cf1707e","An integrated approach to quantitative resilience assessment in process systems","Sun, H. (TU Delft Safety and Security Science; Anhui University of Technology; China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science); Wang, Haiqing (China University of Petroleum (East China))","","2024","Chemical process systems are becoming more automated and complex, which leads to increased interaction and interdependence between the human and technical elements of process systems. This urges the need for updating the safety assessment method by treating “safety” as an emergent property of a system. Uncertainty comes together with complexity. To enhance system ability of dealing with uncertain disruptions, this paper proposes a quantitative resilience assessment method by modeling the failure propagation (initiated by a disruption) across the functional units of a system. The Functional Resonance Analysis Method (FRAM) is utilized to model the system operation to represent the relationship among its function units and to consider the interactions among human-technical factors. Then, a Cascading Failure Propagation Model (CFPM) is developed to quantify the fault propagation process and reflect the system functionality changes over time for resilience assessment. The proposed method is applied to a propane-feeding control system. The results show that it can help practitioners understand the process of fault propagation and risk increase, identify potential ways to design a more resilient system to respond to uncertain disruptions/attacks, and provide a real-time dynamic resilience profile to support decision-making.","Human-technical systems, FRAM, resilience; Process safety","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-13","","","Safety and Security Science","","",""
"uuid:d7b524bf-ebcb-4b06-8fe8-6841e00e78cd","http://resolver.tudelft.nl/uuid:d7b524bf-ebcb-4b06-8fe8-6841e00e78cd","X-ray tomography for fully-3D time-resolved reconstruction of bubbling fluidized beds","Graas, Adriaan B.M. (Centrum Wiskunde & Informatica (CWI)); Wagner, E.C. (TU Delft ChemE/O&O groep); van Leeuwen, Tristan (Centrum Wiskunde & Informatica (CWI)); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering); Batenburg, K. Joost (Universiteit Leiden); Lucka, Felix (Centrum Wiskunde & Informatica (CWI)); Portela, L. (TU Delft ChemE/Transport Phenomena)","","2024","A new X-ray computed tomography technique for the purpose of imaging fluidized beds is presented. It consists of an experimental set-up with three stationary X-ray source and flat panel detector pairs, a geometric calibration and data processing workflow, and an image reconstruction algorithm. The technique enables sparse-angular tomographic reconstruction in large 3D regions of fluidized beds at framerates up to 200 Hz, and therefore images bubbles along their whole trajectories through the volume. It allows for a unique analysis of bubble dynamics in fluidized beds, including bubble velocities, bubble transformations, i.e., time evolution of the bubble distributions in space, and bubble–bubble interactions. In this article, we first analyze the main limitation of the technique, the sparse angular resolution, through numerical simulations. We then test the experimental set-up through imaging a series of phantoms. Lastly, we demonstrate results from a Geldart B bubbling fluidized bed.","Computed Tomography; Dynamic imaging; Fluidized beds; Gas–solids; Iterative image reconstruction; X-ray imaging set-up","en","journal article","","","","","","","","","","","ChemE/O&O groep","","",""
"uuid:9f779f6b-bf1a-42cd-8610-8bf9b565f44e","http://resolver.tudelft.nl/uuid:9f779f6b-bf1a-42cd-8610-8bf9b565f44e","From metagenomes to metabolism: Systematically assessing the metabolic flux feasibilities for “Candidatus Accumulibacter” species during anaerobic substrate uptake","Páez Watson, T.W. (TU Delft BT/Environmental Biotechnology); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Wahl, S.A. (TU Delft BT/Industriele Microbiologie)","","2024","With the rapid growing availability of metagenome assembled genomes (MAGs) and associated metabolic models, the identification of metabolic potential in individual community members has become possible. However, the field still lacks an unbiassed systematic evaluation of the generated metagenomic information to uncover not only metabolic potential, but also feasibilities of these models under specific environmental conditions. In this study, we present a systematic analysis of the metabolic potential in species of ""Candidatus Accumulibacter"", a group of polyphosphate-accumulating organisms (PAOs). We constructed a metabolic model of the central carbon metabolism and compared the metabolic potential among available MAGs for “Ca. Accumulibacter” species. By combining Elementary Flux Modes Analysis (EFMA) with max-min driving force (MDF) optimization, we obtained all possible flux distributions of the metabolic network and calculated their individual thermodynamic feasibility. Our findings reveal significant variations in the metabolic potential among “Ca. Accumulibacter” MAGs, particularly in the presence of anaplerotic reactions. EFMA revealed 700 unique flux distributions in the complete metabolic model that enable the anaerobic uptake of acetate and its conversion into polyhydroxyalkanoates (PHAs), a well-known phenotype of “Ca. Accumulibacter”. However, thermodynamic constraints narrowed down this solution space to 146 models that were stoichiometrically and thermodynamically feasible (MDF > 0 kJ/mol), of which only 8 were strongly feasible (MDF > 7 kJ/mol). Notably, several novel flux distributions for the metabolic model were identified, suggesting putative, yet unreported, functions within the PAO communities. Overall, this work provides valuable insights into the metabolic variability among ""Ca. Accumulibacter"" species and redefines the anaerobic metabolic potential in the context of phosphate removal. More generally, the integrated workflow presented in this paper can be applied to any metabolic model obtained from a MAG generated from microbial communities to objectively narrow the expected phenotypes from community members.","Elementary flux modes; Metabolic predictions; Metagenome-assembled genomes; Pathway thermodynamics","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:29167aa8-16b8-4564-bb4e-cd5d44e1829f","http://resolver.tudelft.nl/uuid:29167aa8-16b8-4564-bb4e-cd5d44e1829f","Estimating the effect of assumed initial damage to the hydraulic stability of pattern-placed revetments on dikes using finite element modeling","van der Vegt, N. (TU Delft Hydraulic Structures and Flood Risk; HKV Consultants); Klerk, W.J. (TU Delft Hydraulic Structures and Flood Risk; Deltares); Peters, D.J. (TU Delft Hydraulic Structures and Flood Risk); van Gent, M.R.A. (TU Delft Coastal Engineering; Deltares); Hofland, Bas (TU Delft Hydraulic Structures and Flood Risk)","","2024","Initial damage, caused by previous wave loading or other events, might affect the hydraulic stability of pattern-placed revetments. Three common types of damage are considered in this study. The effect of this assumed initial damage on the hydraulic stability and failure probability of revetments is quantified using a FEM model. This model is developed using data from large-scale flume and field experiments. Using results from the FEM model, surrogate models are created to predict the effect of each type of initial damage on the hydraulic stability and failure probability. Through the use of these surrogate models, it is demonstrated that S-shaped deformation caused by filter migration around the wave impact zone has the largest effect on the hydraulic stability decreasing up to 30%, and failure probability per year increasing up to 10,000 times. When the granular filling between the joints of the columns is washed-out, the stability decreases up to 29% and the failure probability increases up to 700 times. A missing column has a limited effect on the hydraulic stability and failure probability when there is no other (structural) damage. However, if it originates from underlying damage, it might be an initial sign of total failure of the revetment. This study demonstrates the effectiveness of finite element modeling for studying (damaged) revetments, which can be used to complement flume experiments. The results can be used to prioritize maintenance efforts in risk-based maintenance of pattern-placed revetments.","Dikes; Finite element modeling; Flood defenses; Pattern-placed revetment; Reliability analysis; Risk-based maintenance; Surrogate modeling; Vulnerability; Wave impact","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:d51ff694-d672-4d8c-b7dd-7e60fbd38bb6","http://resolver.tudelft.nl/uuid:d51ff694-d672-4d8c-b7dd-7e60fbd38bb6","Repeatability of beach morphology change under identical wave forcing","Blenkinsopp, Chris E. (University of Bath); Hunter, Alan J. (University of Bath); Baldock, Tom E. (University of Queensland); Bayle, P.B. (TU Delft Environmental Fluid Mechanics; University of Bath); Bosboom, J. (TU Delft Coastal Engineering); Conley, Daniel (Plymouth University); Masselink, Gerd (Plymouth University)","","2024","Laboratory investigations of beach morphology change under wave action are undertaken to gain insight into coastal processes, design coastal structures and validate the predictions of numerical models. For the results of such experiments to be reliable, it is necessary that they are repeatable. The equilibrium beach concept, that beach morphology will evolve to a quasi-static equilibrium shape for a given forcing suggests that experiments should be repeatable to some degree. However, sediment transport in turbulent breaking and broken waves is complex and highly variable and the level of repeatability at different temporal and spatial scales is challenging to measure, as such, previous work has restricted comparisons to small numbers of waves. Here we use the results of two identical, 20-h large-scale wave flume experiments to investigate the repeatability of sediment transport and beach morphology change under waves at timescales down to individual swash events. It is shown that while flow characteristics from identical swash events are very repeatable, the sediment transported can be very different in both magnitude and direction due to differences in turbulence, sediment advection and morphological feedback. Over longer periods containing multiple matching swash events however, the beach responds in a very similar manner, with the level of morphological repeatability increasing with time. The results also demonstrate that gross swash zone sediment transport remains high even as a beach profile approaches quasi-equilibrium, but the proportion of individual swash events that cause large sediment fluxes (>±7.5 kg/event/m) reduces with time. The results of this laboratory study indicate that beach morphology change has a level of determinism over timescales of several minutes and longer, giving confidence in the results from physical modelling studies. However, the large differences in sediment transport from apparently identical swash events questions the value in pursuing numerical predictions of sediment transport at the wave-by-wave timescale unless the reversals in sediment transport between apparently near identical swash events can also be predicted.","","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:d485dc1e-2235-44f3-8429-c01a03404dbd","http://resolver.tudelft.nl/uuid:d485dc1e-2235-44f3-8429-c01a03404dbd","Alkali-Activated Foams Coated with Colloidal Ag for Point-of-Use Water Disinfection","Bhuyan, Mohammad Amzad Hossain (University of Oulu); Karkman, Antti (University of Helsinki); Prokkola, Hanna (University of Oulu); Chen, B. (TU Delft Materials and Environment); Perumal, Priyadharshini (University of Oulu); Luukkonen, Tero (University of Oulu)","","2024","Alkali-activated foams are ceramic-like materials prepared at near-ambient temperature. This study investigates them for point-of-use water disinfection, thus providing an alternative to ceramic filters fired at a high temperature. Alkali-activated foams with different compositions were characterized for the porosity, mechanical strength, shrinkage, and microstructure. The optimized foam, employing metakaolin as the raw material, was coated with a colloidal Ag solution. The disinfection performance and leaching behavior of the foams was followed in a continuous 10 week experiment, where clean water with a weekly pulse of contaminated water was distributed through the foam. The average inactivation of Escherichia coli with the Ag-coated foam was 2.84 log10, which was 1.27 units higher compared to foam without Ag. A quantitative polymerase chain reaction analysis and metagenomic sequencing verified that foams with and without Ag were both capable of reducing the microbial load. Furthermore, the changes induced by the foam with Ag on the microbial community composition, antibiotic resistome, and metal and biocide resistomes were significant. The leached concentrations of Ag, Na, Si, and Al were in accordance with the drinking water guidelines. Finally, a life cycle assessment indicated the possibility of reducing the global warming potential and the total embodied energy in comparison with a conventional ceramic filter.","alkali-activated materials; geopolymers; point-of-use water treatment; water disinfection; water supply","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:668f4221-3a32-4176-89d0-dc1c2830a851","http://resolver.tudelft.nl/uuid:668f4221-3a32-4176-89d0-dc1c2830a851","Air entrapment modelling during pipe filling based on SWMM","Ferreira, J.P. (TU Delft Sanitary Engineering); Ferràs, David (IHE Delft Institute for Water Education); Covas, Dídia I.C. (University of Lisbon); van der Werf, Job (TU Delft Sanitary Engineering); Kapelan, Z. (TU Delft Sanitary Engineering)","","2024","The paper proposes a novel methodology to locate and quantify entrapped air pockets created during pipe-filling events often found in intermittent water supply systems. Different filling conditions were tested in an experimental pipe with a high point. Measurements were taken and video recordings were carried out to assess air pocket volumes for different air release conditions at the downstream end of the pipe. The stochastic nature of air pocket creation resulted in varying air volumes. A new numerical model capable of simulating the air pocket creation, dragging and entrainment has been proposed. The new model, AirSWMM, was implemented as an extension of the Stormwater Management Model (SWMM) with stochasticity of air pocket formation reproduced by simulations with different air entrainment rates. The obtained numerical results show that the proposed model, even though based on a single-phase one-dimensional flow, can accurately locate and approximately quantify the entrapped air pocket volumes.","air pocket entrapment; Air–water interface interaction; flow visualization and imaging; intermittent water supply; SWMM; water pipelines","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:361ebc5f-5249-43e0-a8a5-ae38cddbec68","http://resolver.tudelft.nl/uuid:361ebc5f-5249-43e0-a8a5-ae38cddbec68","The importance of time-varying, non-tidal currents in modelling in-situ sand wave dynamics","Overes, P.H.P. (TU Delft Applied Mechanics; University of Twente); Borsje, B. W. (University of Twente); Luijendijk, Arjen (TU Delft Coastal Engineering); Hulscher, S. J.M.H. (University of Twente)","","2024","Sand waves are found on shallow, sandy seabeds throughout the world and their dynamics may pose an imminent threat to offshore construction. Therefore, there is a pressing need to understand bed level dynamics in sand wave areas. These bed level dynamics lead to variations in sand wave shape and migration rate over time. However, these variations cannot be explained with the present-day process-based sand wave models, which all include a purely periodic tidal forcing. To explain these fluctuations a more intricate description of the hydrodynamics is necessary. The aim of this study is to explore the importance of time-varying, non-tidal currents for sand wave dynamics in the North Sea. We adopted the three-dimensional Delft3D-Flexible Mesh model, and were able to reconstruct time-varying, non-tidal currents on top of the periodic tidal forcing, while significantly reducing computation times. The simulated currents and water levels showed a good agreement with in-situ measurements. Compared to the situation with only tidal forcing, the simulated sedimentation and erosion rates were amplified up to 15 times due to time-varying, non-tidal currents. Additionally, periods of net erosion were found at locations in the sand wave transect where tidally forced models only showed net-sedimentation. It is therefore important to consider time-varying, non-tidal currents when predicting future sand wave dynamics in the field.","ADCP field measurements; Delft3D Flexible Mesh; Hydrodynamic modelling; Marine dunes; Sediment transport modelling; Tidal sand waves","en","journal article","","","","","","","","","","","Applied Mechanics","","",""
"uuid:179cab11-2b3a-4d78-b841-7ccb54345d96","http://resolver.tudelft.nl/uuid:179cab11-2b3a-4d78-b841-7ccb54345d96","Transfer learning for improved generalizability in causal physics-informed neural networks for beam simulations","Kapoor, T. (TU Delft Railway Engineering); Wang, H. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering)","","2024","This paper proposes a novel framework for simulating the dynamics of beams on elastic foundations. Specifically, partial differential equations modeling Euler–Bernoulli and Timoshenko beams on the Winkler foundation are simulated using a causal physics-informed neural network (PINN) coupled with transfer learning. Conventional PINNs encounter challenges in handling large space–time domains, even for problems with closed-form analytical solutions. A causality-respecting PINN loss function is employed to overcome this limitation, effectively capturing the underlying physics. However, it is observed that the causality-respecting PINN lacks generalizability. We propose using solutions to similar problems instead of training from scratch by employing transfer learning while adhering to causality to accelerate convergence and ensure accurate results across diverse scenarios. The primary contribution of this paper lies in introducing a causality-respecting PINN loss function in the context of structural engineering and coupling it with transfer learning to enhance the generalizability of PINNs in simulating the dynamics of beams on elastic foundations. Numerical experiments on the Euler–Bernoulli beam highlight the efficacy of the proposed approach for various initial conditions, including those with noise in the initial data. Furthermore, the potential of the proposed method is demonstrated for the Timoshenko beam in an extended spatial and temporal domain. Several comparisons suggest that the proposed method accurately captures the inherent dynamics, outperforming the state-of-the-art physics-informed methods under standard L2-norm metric and accelerating convergence.","Biharmonic equations; Causality; Elastic foundation; Euler–Bernoulli beam; Physics-informed neural networks (PINNs); Timoshenko beam; Transfer learning","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:95ba2a4b-52d9-4aa5-a41a-6c608a13e176","http://resolver.tudelft.nl/uuid:95ba2a4b-52d9-4aa5-a41a-6c608a13e176","Measuring the impacts of human and organizational factors on human errors in the Dutch construction industry using structured expert judgement","Ren, X. (TU Delft Safety and Security Science); Nane, G.F. (TU Delft Applied Probability); Terwel, K.C. (TU Delft Applied Mechanics); van Gelder, P.H.A.J.M. (TU Delft Safety and Security Science)","","2024","This study focuses on measuring the influence of critical Human and Organizational Factors (HOFs) on human error occurrence in structural design and construction tasks within the context of the Dutch construction industry. The primary research question addressed in this paper concerns the extent of HOFs’ contribution to human error occurrence. To answer this question, the Classical Model for Structured Expert Judgement (SEJ) is employed, enabling experts to provide their judgments on task Human Error Probability (HEP) influenced by different HOFs, which are subsequently aggregated mathematically. SEJ is chosen as a suitable approach due to the limited availability of applicable data in the construction sector. As a result, the impacts of HOFs are quantified as multipliers, representing the ratio between the observed or evaluated task HEP and its baseline value. These multipliers are then compared with corresponding multipliers from existing Human Reliability Analysis methods and studies. The findings reveal that fitness-for-duty, organizational characteristics and fragmentation exhibit the most pronounced negative effects, whereas complexity, attitude and fitness-for-duty demonstrate the most significant positive impacts on task performance. These results offer valuable insights that can be applied to enhance structural safety assurance practices.","Classical model; Human and organizational factors; Human error probability; Structural safety; Structured expert judgement","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-24","","","Safety and Security Science","","",""
"uuid:7bacb3b9-e1bc-4dab-b6a1-9069f6a03221","http://resolver.tudelft.nl/uuid:7bacb3b9-e1bc-4dab-b6a1-9069f6a03221","Transport of Magma in Granitic Mush Systems; an Example From the Götemar Pluton, Sweden","Mattsson, Tobias (Stockholm University; University of St Andrews); McCarthy, William (University of St Andrews); Schmiedel, T. (TU Delft Resource Engineering; Uppsala University)","","2024","Granitic magma bodies form in the ephemeral part of magma mush systems and are emplaced by a variety of mechanisms in different tectonic settings. This study investigates how granitic magma emplacement processes and tectonomagmatic interactions assert control over the architecture of mush state pluton-scale magma transport pathways. The 1.45 Ga shallow-crustal Götemar pluton is a 4.5 km diameter circular pluton that consists of three granite units: a coarse-grained red granite, a medium-grained pale to red granite, and fine-grained pale microgranite sheets. We employed geological mapping supported by Anisotropy of Magnetic Susceptibility (AMS) to examine the magmatic and regional tectonic controls on late-stage magma transport in the Götemar granitic magma mush system. Multiple parallel arcuate subhorizontal microgranite and medium-grained granite sheets (from 0.1 to 10s of meters thick) were mapped within the pluton. The arcuate sheets pinch out from the northern part of the pluton toward the SE inferring magma propagation direction. A dominant set of vertical granitic sheets within the granite body strikes NW-SE. The AMS fabrics are contact-parallel in the main medium-grained granite body and indicate inflation. Within the microgranite sheets, the AMS fabrics are parallel to the sheet strike and support a sheet propagation direction to the SE. The Götemar pluton displays a clear link between arcuate (concentric) magma-transporting sheets and concentric strain-partitioning related to the intrusion of medium-grained granite magma. The vertical magma sheet orientations are consistent with an NE-SW extensional stress field that is associated with the extensional back-arc stress regime of the contemporary Hallandian Orogen.","granite; magma mush; magma sheets; melt migration; pluton emplacement","en","journal article","","","","","","","","","","","Resource Engineering","","",""
"uuid:52df0c69-3208-4d29-a461-c6afaf3213e0","http://resolver.tudelft.nl/uuid:52df0c69-3208-4d29-a461-c6afaf3213e0","Hamiltonian Monte Carlo to Characterize Induced Earthquakes: Application to a ML 3.4 Event in the Groningen Gas Field and the Role of Prior","Masfara, La ODE Marzujriban (TU Delft Applied Geophysics and Petrophysics; Royal Netherlands Meteorological Institute (KNMI)); Weemstra, C. (TU Delft Applied Geophysics and Petrophysics; Royal Netherlands Meteorological Institute (KNMI))","","2024","The Hamiltonian Monte Carlo algorithm is known to be highly efficient when sampling high-dimensional model spaces due to Hamilton's equations guiding the sampling process. For weakly non-linear problems, linearizing the forward problem enhances this efficiency. This study integrates this linearization with geological prior knowledge for optimal results. We test this approach to estimate the source parameters of a 3.4 magnitude induced event that originated in the Groningen gas field in 2019. The source parameters are the event's centroid (three components), its moment tensor (six components), and its origin time. In terms of prior knowledge, we tested two sets of centroid priors. The first set exploits the known fault geometry of the Groningen gas field, whereas the second set is generated by placing initial centroid priors on a uniform horizontal grid at a depth of 3 km (the approximate depth of the gas reservoir). As for the forward problem linearization, we use an approach in which the linearization is run iteratively in tandem with updates of the centroid prior. We demonstrate that, in the absence of a sufficiently accurate initial centroid prior, the linearization of the forward model necessitates multiple initial centroid priors. Eventually, both prior sets yield similar posteriors. Most importantly, however, they agree with the geological knowledge of the area: the posterior peaks for model vectors containing a centroid near a major fault and a moment tensor that corresponds to normal faulting along a plane with a strike almost aligning with that of the major fault.","Bayesian; Groningen; induced seismicity; inversion; moment tensor; probabilistic","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:6da9cf1d-1a6e-4ca7-8253-d809acf56066","http://resolver.tudelft.nl/uuid:6da9cf1d-1a6e-4ca7-8253-d809acf56066","Mode I fracture behavior of glass fiber composite-steel bonded interface: Experiments and CZM","He, P. (TU Delft Steel & Composite Structures); Moreira Arouche, M. (TU Delft Steel & Composite Structures); Koetsier, M. (TU Delft Steel & Composite Structures); Pavlovic, M. (TU Delft Steel & Composite Structures)","","2024","Debonding is characterized as the governing failure mode in the innovative wrapped composite joints made with glass fiber composite material wrapped around steel hollow sections without welding. The prerequisite for predicting debonding failure of wrapped composite joints is to obtain fracture behavior of the composite-steel bonded interface. The mode I fracture behavior of the bonded interface was experimentally investigated using glass fiber composite-steel double cantilever beam (DCB) specimens. The crack length a and the crack tip opening displacement (CTOD) during the test were accurately measured by analyzing the digital image correlation (DIC) data while the strain energy release rate (SERR) was calculated through the extended global method (EGM). The cohesive zone modeling (CZM) was utilized in the finite element model with the proposal of a four-linear traction-separation law to simulate the mode I fracture process. An approach is introduced to determine the critical stages of the proposed four-linear cohesive law by combining accurate measurements of crack length a and CTOD, along with SERR values. The validity of the four-linear cohesive law and the introduced approach to determine the critical stages were confirmed by good agreement in both global and local behavior between the testing and the FEA results.","Composite-steel bonded interface; CZM; DCB; DIC; Four-linear traction-separation law; mode I fracture behavior","en","journal article","","","","","","","","","","","Steel & Composite Structures","","",""
"uuid:d466d4b0-2c3b-4257-afd9-234ecfeec0e6","http://resolver.tudelft.nl/uuid:d466d4b0-2c3b-4257-afd9-234ecfeec0e6","A global analysis of how human infrastructure squeezes sandy coasts","Lansu, Eva M. (NIOZ Royal Netherlands Institute for Sea Research; University Medical Center Groningen); Reijers, Valérie C. (Universiteit Utrecht); Höfer, Solveig (NIOZ Royal Netherlands Institute for Sea Research; University Medical Center Groningen); Luijendijk, Arjen (TU Delft Coastal Engineering; Deltares); Rietkerk, Max (Universiteit Utrecht); Wassen, Martin J. (Universiteit Utrecht); Lammerts, Evert Jan (Staatsbosbeheer); van der Heide, Tjisse (NIOZ Royal Netherlands Institute for Sea Research; University Medical Center Groningen)","","2024","Coastal ecosystems provide vital services, but human disturbance causes massive losses. Remaining ecosystems are squeezed between rising seas and human infrastructure development. While shoreline retreat is intensively studied, coastal congestion through infrastructure remains unquantified. Here we analyse 235,469 transects worldwide to show that infrastructure occurs at a median distance of 392 meter from sandy shorelines. Moreover, we find that 33% of sandy shores harbour less than 100 m of infrastructure-free space, and that 23–30% of this space may be lost by 2100 due to rising sea levels. Further analyses show that population density and gross domestic product explain 35–39% of observed squeeze variation, emphasizing the intensifying pressure imposed as countries develop and populations grow. Encouragingly, we find that nature reserves relieve squeezing by 4–7 times. Yet, at present only 16% of world’s sandy shores have a protected status. We therefore advocate the incorporation of nature protection into spatial planning policies.","","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:ba125b1b-145c-4d70-a678-c921d0e2a800","http://resolver.tudelft.nl/uuid:ba125b1b-145c-4d70-a678-c921d0e2a800","Catalytic pre-coat on ceramic nanofiltration membranes for segregation and Fenton cleaning of high-resistance colloids in direct surface water treatment","Lin, B. (TU Delft Sanitary Engineering; Nanjing Tech University); Heijman, Sebastiaan (TU Delft Sanitary Engineering); Rietveld, L.C. (TU Delft Sanitary Engineering)","","2024","Ceramic nanofiltration (NF) is a promising alternative for direct surface water treatment, but is hampered for full-scale applications by fouling and a lack of eco-friendly cleaning regimes. In this work, an innovative reactive pre-coat layer, consisting of an iron oxychloride catalyst, was constructed on top of commercial ceramic NF membranes, for segregating a large-sized colloid fraction in canal water and Fenton cleaning with a hydrogen peroxide (H2O2) solution. The large-sized colloids (3−30 μm) were identified as dominant substances fouling the TiO2 separation layer of the pristine membranes, leading to a fast increase in their filtration resistance, in contrast to the small-sized colloids (<0.04 μm) and natural organic matter (NOM). As a consequence, the catalyst pre-coat layer with a pore size of 0.1–0.5 μm was able to segregate the large-sized colloids from the TiO2 separation layer during direct filtration of the raw water. Moreover, filtration under an acceptable flux of around 23 L m−2 h−1 did not cause pore clogging in the catalyst pre-coat. In addition, Fenton oxidation initiated by the catalytic pre-coat efficiently restored the filtration resistance, whereas sole H2O2 flush of the pristine membrane was not effective. In the meantime, the TiO2 separation layer of the membrane exerted a high NOM rejection of approximately 90%, measured as dissolved organic carbon, while the catalyst pre-coat on the membrane remained active in Fenton cleaning, over five one-day cycles. The findings of this work may provide guidance on the structural and functional design of a catalytic pre-coat layer for a dual purpose of foulant segregation and oxidative removal, particularly in response to key fouling-causing substances, during membrane-based treatment of real water matrices.","Catalytic pre-coat; Ceramic nanofiltration membrane; Fenton cleaning; Membrane fouling; Surface water","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:d4911200-ed9b-42fd-abfd-6f923fddc871","http://resolver.tudelft.nl/uuid:d4911200-ed9b-42fd-abfd-6f923fddc871","Two-phase flow metering of maldistribution inside a header by means of venturi flowmeter solely","Lecardonnel, A. (TU Delft Flight Performance and Propulsion; von Karman Institute for Fluid Dynamics); de Servi, C.M. (TU Delft Flight Performance and Propulsion); Colonna, Piero (TU Delft Flight Performance and Propulsion); Laboureur, D. (von Karman Institute for Fluid Dynamics)","","2024","In evaporators, the distribution of the liquid and vapor phases among the channels is a convoluted problem, depending on a wide range of parameters. However, maldistribution causes important losses of performance. Due to their complexity, the accurate modeling of such two-phase flows is difficult to handle. Hence, experimental studies are still of great importance to help the understanding of maldistribution behaviors inside evaporators. Most of the experimental investigations of two-phase flow distribution are measuring the liquid and vapor quantities in the channels through a phase separation process, increasing the test duration and complexity. As a consequence, the number of parameters investigated is usually limited. Therefore, a new inline instrumentation method would allow for a more complete study by simplifying the measurement process. In the present work, an isothermal air/water mixture was used as fluid. The distribution of the two phases in eight channels of 10-mm I.D. connected to a simplified header was investigated. The inlet mass flow rates considered ranged from 0 to 0.025 kg/s for the water, and from 0 to 0.022 kg/s for the air. Consequently, qualities x up to 0.7 and void fractions ® up to 0.9 were reached. All the tests were carried at a pressure condition of 7 bar to reach a liquid to vapor density ratio similar to what is encountered for traditional refrigerant. Finally, to allow a continuous measurement process, the mass flow rates in each of the 10-mm I.D. channel were measured using a flowmeter calibrated on a separate line. Since no void fraction meter was coupled, a new iterative methodology, based on the Venturi pressure drops measurement solely, was developed and is proposed here. It proved to successfully predict the vapor and liquid phase flow rates in each channel.","evaporators; experimental; heat exchanger; liquid-gas two-phase flow; maldistribution; metering instrumentation; Venturi","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-01","","","Flight Performance and Propulsion","","",""
"uuid:2568936b-2f64-4f89-8d08-41b38e949bc0","http://resolver.tudelft.nl/uuid:2568936b-2f64-4f89-8d08-41b38e949bc0","Investigation of the first quasi-rectangular metro tunnel constructed by the 0−θ method","Li, Peinan (Donghua University); Liu, Xue (Donghua University); Jiang, Xi (University of Tennessee); Zhang, X. (TU Delft Geo-engineering); Wu, Jun (Shanghai University of Engineering Science); Chen, Peixin (Shanghai Tunnel Engineering Co. Ltd.)","","2024","Quasi-rectangular shield tunneling is a cutting-edge trenchless method for constructing metro tunnels with double tubes, owing to its advantages in saving underground space and reducing ground disturbance. However, the conventional quasi-rectangular shield tunneling method is not applicable when constructing a tunnel without a center pillar, such as a scissor crossover section of a metro line. Therefore, the 0−θ tunneling method, which combines the quasi-rectangular shield and pipe jacking methods, was investigated in this study to solve the aforementioned construction challenges. This study presents a case study of the Sijiqing Station of the Hangzhou Metro Line 9 in China, in which the 0−θ method was first proposed and applied. Key techniques such as switching between two types of tunneling modes and the tunneling process control in complex construction environments were investigated. The results demonstrated that the 0−θ method can address the technical challenges presented by the post-transition line with a high curvature and a scissors crossover line. In addition, the adoption of the 0−θ method ensured that the transformation between shield tunneling and pipe jacking was safe and efficient. The ground settlement monitoring results demonstrated that the disturbance to the surrounding environment can be limited to a safe level. This case study contributes to the construction technology for a metro tunnel containing both post-transition lines with a small turning radius and a scissors crossover line. A practical construction experience and theoretical guidance were provided in this study, which are of significance for both the industry and academia.","0−θ method; pipe jacking; quasi-rectangular tunnel; shield tunneling; underground space","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-11","","","Geo-engineering","","",""
"uuid:12acb63e-81f0-4df1-8095-a767ad8b46ee","http://resolver.tudelft.nl/uuid:12acb63e-81f0-4df1-8095-a767ad8b46ee","Corrigendum to “Estimating bridge criticality due to extreme traffic loads in highway networks” [Eng. Struct. vol. 300, 1 February 2024, 117172] (Engineering Structures (2024) 300, (S0141029623015870), (10.1016/j.engstruct.2023.117172))","Mendoza Lugo, M.A. (TU Delft Hydraulic Structures and Flood Risk); Nogal Macho, M. (TU Delft Integral Design & Management); Morales Napoles, O. (TU Delft Hydraulic Structures and Flood Risk)","","2024","The authors regret the acknowledgments in the published article are incomplete. The complete acknowledgments are as follows: “This research was supported by the Mexican National Council for Science and Technology (CONACYT) under project number 2019-000021-01EXTF-00564 CVU 784544. The authors would like to thank Dr. Andrés Antonio Torres Acosta, Research Professor at the Department of Sustainable and Civil Technologies, School of Engineering and Sciences, Tecnológico de Monterrey for his contributions to this research.” The authors would like to apologise for any inconvenience caused. ____________________________.","","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:180bcc96-99e1-4d0a-83bf-e04a527bd8ad","http://resolver.tudelft.nl/uuid:180bcc96-99e1-4d0a-83bf-e04a527bd8ad","Microwave spectroscopy of interacting Andreev spins","Wesdorp, J.J. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Vaartjes, A. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Grünhaupt, L. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Roelofs, S.R. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Splitthoff, L.J. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Pita-Vidal, Marta (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bargerbos, A. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Andersen, C.K. (TU Delft Andersen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2024","Andreev bound states are fermionic states localized in weak links between superconductors which can be occupied with spinful quasiparticles. Microwave experiments using superconducting circuits with InAs/Al nanowire Josephson junctions have recently enabled probing and coherent manipulation of Andreev states but have remained limited to zero or small magnetic fields. Here, we use a flux-tunable superconducting circuit compatible in magnetic fields up to 1T to perform spectroscopy of spin-polarized Andreev states up to ∼250mT, beyond which the spectrum becomes gapless. We identify singlet and triplet states of two quasiparticles occupying different Andreev states through their dispersion in magnetic field. These states are split by exchange interaction and couple via spin-orbit coupling, analogously to two-electron states in quantum dots. We also show that the magnetic field allows to drive a direct spin-flip transition of a single quasiparticle trapped in the junction. Finally, we measure a gate- and field-dependent anomalous phase shift of the Andreev spectrum, of magnitude up to ∼0.7π. Our observations demonstrate alternative ways to manipulate Andreev states in a magnetic field and reveal spin-polarized triplet states that carry supercurrent.","","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:a439dbf6-4244-4181-b411-030505028d5d","http://resolver.tudelft.nl/uuid:a439dbf6-4244-4181-b411-030505028d5d","Efficient and robust estimation of many-qubit Hamiltonians","Stilck França, Daniel (University of Copenhagen; Ecole Normale Supérieure de Lyon); Markovich, L. (TU Delft QID/Borregaard Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Universiteit Leiden); Dobrovitski, V.V. (TU Delft QID/Dobrovitski Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Werner, Albert H. (University of Copenhagen); Borregaard, J. (TU Delft QN/Borregaard groep; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Harvard University)","","2024","Characterizing the interactions and dynamics of quantum mechanical systems is an essential task in developing quantum technologies. We propose an efficient protocol based on the estimation of the time-derivatives of few qubit observables using polynomial interpolation for characterizing the underlying Hamiltonian dynamics and Markovian noise of a multi-qubit device. For finite range dynamics, our protocol exponentially relaxes the necessary time-resolution of the measurements and quadratically reduces the overall sample complexity compared to previous approaches. Furthermore, we show that our protocol can characterize the dynamics of systems with algebraically decaying interactions. The implementation of the protocol requires only the preparation of product states and single-qubit measurements. Furthermore, we improve a shadow tomography method for quantum channels that is of independent interest and discuss the robustness of the protocol to various errors. This protocol can be used to parallelize the learning of the Hamiltonian, rendering it applicable for the characterization of both current and future quantum devices.","","en","journal article","","","","","","","","","","","QID/Borregaard Group","","",""
"uuid:16f0ede3-390a-4e7f-bb2d-cc873d6a4062","http://resolver.tudelft.nl/uuid:16f0ede3-390a-4e7f-bb2d-cc873d6a4062","Radiologic Assessment of Interbody Fusion: A Systematic Review on the Use, Reliability, and Accuracy of Current Fusion Criteria","Duits, Anneli A.A. (University Medical Center Utrecht; Diakonessehuis Utrecht); Van Urk, Paul R. (University Medical Center Utrecht); Lehr, A. Mechteld (University Medical Center Utrecht); Nutzinger, Don (University Medical Center Utrecht); Reijnders, Maarten R.L. (University Medical Center Utrecht); Weinans, Harrie (TU Delft Biomaterials & Tissue Biomechanics; University Medical Center Utrecht); Foppen, Wouter (University Medical Center Utrecht); Oner, F. Cuhmur (University Medical Center Utrecht); Van Gaalen, Steven M. (University Medical Center Utrecht; Acibadem International Medical Center); Kruyt, Moyo C. (University Medical Center Utrecht; University of Twente)","","2024","Background: Lumbar interbody fusion (IF) is a common procedure to fuse the anterior spine. However, a lack of consensus on image-based fusion assessment limits the validity and comparison of IF studies. This systematic review aims to (1) report on IF assessment strategies and definitions and (2) summarize available literature on the diagnostic reliability and accuracy of these assessments. Methods: Two searches were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Search 1 identified studies on adult lumbar IF that provided a detailed description of image-based fusion assessment. Search 2 analyzed studies on the reliability of specific fusion criteria/classifications and the accuracy assessed with surgical exploration. Results: A total of 442 studies were included for search 1 and 8 studies for search 2. Fusion assessment throughout the literature was highly variable. Eighteen definitions and more than 250 unique fusion assessment methods were identified. The criteria that showed most consistent use were continuity of bony bridging, radiolucency around the cage, and angular motion <5°. However, reliability and accuracy studies were scarce. Conclusion: This review highlights the challenges in reaching consensus on IF assessment. The variability in IF assessment is very high, which limits the translatability of studies. Accuracy studies are needed to guide innovations of assessment. Future IF assessment strategies should focus on the standardization of computed tomography-based continuity of bony bridging. Knowledge from preclinical and imaging studies can add valuable information to this ongoing discussion.","","en","review","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:525f7406-6a57-4981-80bd-4f41a94e684f","http://resolver.tudelft.nl/uuid:525f7406-6a57-4981-80bd-4f41a94e684f","Magnetic hybrid Pd/Fe-oxide nanoparticles meet the demands for ablative thermo-brachytherapy","van Oossanen, R. (TU Delft RST/Medical Physics & Technology; Erasmus MC); Maier, A. (TU Delft BT/Biocatalysis); Godart, Jérémy (Erasmus MC); Pignol, Jean Philippe (Erasmus MC); Denkova, A.G. (TU Delft RST/Applied Radiation & Isotopes); van Rhoon, Gerard C. (Erasmus MC); Djanashvili, K. (TU Delft BT/Biocatalysis)","","2024","Objective: To investigate the potential of hybrid Pd/Fe-oxide magnetic nanoparticles designed for thermo-brachytherapy of breast cancer, considering their specific loss power (SLP) and clinical constraints in the applied magnetic field. Methods: Hybrid nanoparticles consisting of palladium-core and iron oxide shell of increasing thickness, were suspended in water and their SLPs were measured at varying magnetic fields (12–26 mT peak) and frequencies (50–730 kHz) with a commercial alternating magnetic field generator (magneTherm™ Digital, nanoTherics Ltd.). Results: Validation of the heating device used in this study with commercial HyperMag-C nanoparticles showed a small deviation (±4%) over a period of 1 year, confirming the reliability of the method. The integration of dual thermometers, one in the center and one at the bottom of the sample vial, allowed monitoring of homogeneity of the sample suspensions. SLPs measurements on a series of nanoparticles of increasing sizes showed the highest heating for the diameter of 21 nm (SLP = 225 W/g) at the applied frequencies of 346 and 730 kHz. No heating was observed for the nanoparticles with the size <14 nm, confirming the importance of the size-parameter. The heating ability of the best performing Pd/Fe-oxide-21 was calculated to be sufficient to ablate tumors with a radius ±4 and 12 mm using 10 and 1 mg/mL nanoparticle concentration, respectively. Conclusions: Nanoparticles consisting of non-magnetic palladium-core and magnetic iron oxide shell are suitable for magnetic hyperthermia/thermal ablation under clinically safe conditions of 346 kHz and 19.1 mT, with minimal eddy current effects in combination with maximum SLP.","breast cancer; magnetic hyperthermia; Palladium iron/oxide nanoparticles; thermal ablation; thermo-brachytherapy","en","journal article","","","","","","","","","","","RST/Medical Physics & Technology","","",""
"uuid:e581d782-eaaf-421f-8633-524a0fa9fbf0","http://resolver.tudelft.nl/uuid:e581d782-eaaf-421f-8633-524a0fa9fbf0","Stability of rock-armoured mild slopes","Jumelet, Daan (DEME); van Gent, M.R.A. (TU Delft Coastal Engineering; Deltares); Hofland, Bas (TU Delft Hydraulic Structures and Flood Risk); Kuiper, C. (TU Delft Coastal Engineering; Witteveen+Bos)","","2024","Physical model tests have been performed to study static stability of rock-armoured mild slopes. Current stability design formulae for steeper rock-armoured slopes focus on plunging and surging waves. Slopes of 1:6 and milder usually have more spilling breakers which decreases the load. Also, on mild slopes displaced rocks more often remain present in the wave attack zone, which increases the strength. These aspects lead to an overdesigned structure when existing formulae for steep rock-armoured slopes are used. The present wave flume tests were used to understand the processes and develop a design formula for rock-armoured mild slopes with an impermeable core. These tests were performed for statically stable rock-armoured slopes of 1:6 to 1:10. The tests confirmed that not all existing damage parameters are able to accurately describe the static stability on milder slopes. For mild slopes it is more accurate to describe the damage based on the eroded depth rather than on the eroded area or number of moved stones. In this study, a design formula and guidelines are provided for practicing engineers that design or evaluate the stability of mild rock-armoured slopes.","Armour stability; Coastal structures; Damage characterisation; Design guidelines; Erosion; Mild slopes; Physical model tests; Rock slopes; Slope protection; Wave loading","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:1e058c45-670b-48bb-8645-9ad735386b97","http://resolver.tudelft.nl/uuid:1e058c45-670b-48bb-8645-9ad735386b97","Quantifying the heterogeneous impacts of the urban built environment on traffic carbon emissions: New insights from machine learning techniques","Zhi, Danyue (Beijing Jiaotong University; Technische Universität München); Zhao, Hepeng (China Mobile Group Design Institute Co., Ltd.); Chen, Yan (Beijing Jiaotong University); Song, Weize (Tsinghua University); Song, Dongdong (Beijing Jiaotong University); Yang, Y. (TU Delft Transport and Planning; Beijing Jiaotong University)","","2024","The configuration of the urban built environment is critical for promoting sustainability and achieving carbon neutrality. However, existing studies mostly use linear and spatial econometric models to investigate the relationship between urban built environments and traffic carbon dioxide (CO2) emissions, in-depth studies exploring the heterogeneous impacts of related features on traffic CO2 emission by interpretive machine learning models are scarce. Hence, we extract four dimensionless features to depict the size, compactness, irregularity, and isolation of built-up areas, and road network-related features (i.e., average cluster coefficient, road topological density, and road geometric density), respectively. Subsequently, we develop an interpretive machine learning framework based on the extracted features related to the urban built-up areas and road networks. The interpretive results of the proposed framework uncover that urban morphological features, especially population density (POP), GDP per capita (GDPpc), and urban physical compactness (UPC), have a heterogeneous impact on the per capita traffic emission (PCCE) across different cities. GDPpc is more like a linear relationship with PCCE, and UPC has a significant influence on PCCE when its value is between 62% and 78%. Our results also reveal the nonlinear relationships and interactive effects between these features, providing the implications of urban morphological planning and carbon emission reduction.","Heterogeneous impact; Machine learning; Traffic carbon; Urban built environment","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-24","","","Transport and Planning","","",""
"uuid:e9a46f61-c1f3-49b1-b9e4-de5633921265","http://resolver.tudelft.nl/uuid:e9a46f61-c1f3-49b1-b9e4-de5633921265","Connecting the dots: key insights on ParB for chromosome segregation from single-molecule studies","Tišma, M. (TU Delft BN/Cees Dekker Lab; Kavli institute of nanoscience Delft); Kaljević, Jovana (John Innes Centre); Gruber, Stephan (University of Lausanne); Le, Tung B.K. (John Innes Centre); Dekker, C. (TU Delft BN/Cees Dekker Lab)","","2024","Bacterial cells require DNA segregation machinery to properly distribute a genome to both daughter cells upon division. The most common system involved in chromosome and plasmid segregation in bacteria is the ParABS system. A core protein of this system - partition protein B (ParB) - regulates chromosome organization and chromosome segregation during the bacterial cell cycle. Over the past decades, research has greatly advanced our knowledge of the ParABS system. However, many intricate details of the mechanism of ParB proteins were only recently uncovered using in vitro single-molecule techniques. These approaches allowed the exploration of ParB proteins in precisely controlled environments, free from the complexities of the cellular milieu. This review covers the early developments of this field but emphasizes recent advances in our knowledge of the mechanistic understanding of ParB proteins as revealed by in vitro single-molecule methods. Furthermore, we provide an outlook on future endeavors in investigating ParB, ParB-like proteins, and their interaction partners.","atomic force microscopy; magnetic tweezers; optical tweezers; ParABS system; ParB; single-molecule studies","en","review","","","","","","","","","","","BN/Cees Dekker Lab","","",""
"uuid:591a60f3-f137-419c-9642-1de3fa2861f3","http://resolver.tudelft.nl/uuid:591a60f3-f137-419c-9642-1de3fa2861f3","Modeling the effect of prior austenite grain size on bainite formation kinetics","dos Santos Avila, D. (TU Delft Team Maria Santofimia Navarro); Offerman, S.E. (TU Delft Team Erik Offerman); Santofimia, Maria Jesus (TU Delft Team Maria Santofimia Navarro)","","2024","While experiments show that refining the prior austenite grain size can either accelerate or decelerate bainite formation in steels, kinetic models based on the successive nucleation of bainitic ferrite subunits can only predict an acceleration. In this work we develop a physically-based model for bainite kinetics assuming a displacive growth mechanism which is able to reproduce both faster and slower bainite formation kinetics induced by austenite grain refinement. A theoretical analysis of the model and comparison against published experimental data show that slower kinetics for smaller grains is favored as the difference between the activation energy for grain boundary and autocatalytic nucleation of bainite increases, and as the austenite grain refinement results in finer bainite sub-units. We also theoretically analyze the density of initially present potential nucleation sites for bainite and show that the values of density used in other published bainite nucleation models are mostly underestimated. After using physically consistent values for the density of potential nucleation sites, we were able to calculate the apparent lengthening rate of bainite sheaves which were in line with experimentally measured lengthening rates.","Bainite; grain size; nucleation; phase transformation kinetics; theory and modeling","en","journal article","","","","","","","","","","","Team Maria Santofimia Navarro","","",""
"uuid:76603547-882b-4fd6-8249-d980d3860596","http://resolver.tudelft.nl/uuid:76603547-882b-4fd6-8249-d980d3860596","Control-relevant neural networks for feedforward control with preview: Applied to an industrial flatbed printer","Aarnoudse, Leontine (Eindhoven University of Technology); Kon, Johan (Eindhoven University of Technology); Ohnishi, Wataru (University of Tokyo); Poot, Maurice (Eindhoven University of Technology); Tacx, Paul (Eindhoven University of Technology); Strijbosch, Nard (Eindhoven University of Technology); Oomen, T.A.E. (TU Delft Team Jan-Willem van Wingerden; Eindhoven University of Technology)","","2024","The performance of feedforward control depends strongly on its ability to compensate for reproducible disturbances. The aim of this paper is to develop a systematic framework for artificial neural networks (ANN) for feedforward control. The method involves three aspects: a new criterion that emphasizes the closed-loop control objective, inclusion of preview to deal with delays and non-minimum phase dynamics, and enabling the use of an iterative learning algorithm to generate training data in view of addressing generalization errors. The approach is illustrated through simulations and experiments on an industrial flatbed printer.","Feedforward control; Iterative learning control; Neural networks","en","journal article","","","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:6d851c18-203b-4c97-a56c-99ba178cbcbd","http://resolver.tudelft.nl/uuid:6d851c18-203b-4c97-a56c-99ba178cbcbd","Gas bubble removal from a zero-gap alkaline electrolyser with a pressure swing and why foam electrodes might not be suitable at high current densities","Bleeker, J.J. (TU Delft ChemE/Transport Phenomena); van Kasteren, Celine (Student TU Delft); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering); Vermaas, D.A. (TU Delft ChemE/Transport Phenomena)","","2024","To make green hydrogen more economically attractive, the energy losses in alkaline electrolysis need to be minimized while operating at high current densities (1 A cm−2). At these current densities the ohmic resistance and gas bubbles effects contribute largely to the energy losses. To mitigate the gas bubbles losses, we demonstrate, for the first time, a pressure swing to remove gas bubbles in a zero-gap alkaline water electrolyzer. The pressure swing leverages the ideal gas law to increase the volume of gas in the system periodically, for a short duration (<2 s). This temporal volume increase effectively removes bubbles from the electrolyzer. We show that pressure swing can be used to measure the effect of bubbles on the ohmic resistance (RBubbles). Our results reveal that foam electrodes have a significantly larger RBubbles than perforated plate electrodes (1.8 Ω cm2 vs 0.3 Ω cm2). The time-averaged cell voltage reduces by 170 mV when applying pressure swings to an electrolyzer operating at 200 mA cm−2 in 1 M KOH with foam electrodes. The bubble resistance further depends on the electrolyte conductivity (inversely proportional) and is only moderately affected by operating pressure (25 % lower when increasing pressure amplitude from 1–2 to 1–5 bar). By implementing these findings in a model, we estimate that the pressure swing could reduce the cell voltage by ∼0.1 V for an electrolyzer operating at industrial conditions (6 M KOH, 80 °C, 1 A cm−2) for foam electrodes. For perforated plate electrodes, however, the reduced cell voltage is lower and does not outweigh the additional compression energy.","Alkaline water electrolysis; Gas bubbles; Hydrogen; Pressurized; Zero-gap","en","journal article","","","","","","","","","","","ChemE/Transport Phenomena","","",""
"uuid:da4cbf15-21c8-474a-b79e-47e3a067778d","http://resolver.tudelft.nl/uuid:da4cbf15-21c8-474a-b79e-47e3a067778d","Effects of Grain Boundaries and Surfaces on Electronic and Mechanical Properties of Solid Electrolytes","Xie, Weihang (National University of Singapore); Deng, Zeyu (National University of Singapore); Liu, Zhengyu (National University of Singapore); Famprikis, T. (TU Delft RST/Storage of Electrochemical Energy); Butler, Keith T. (University College London (UCL)); Canepa, Pieremanuele (National University of Singapore; University of Houston)","","2024","Extended defects, including exposed surfaces and grain boundaries (GBs), are critical to the properties of polycrystalline solid electrolytes in all-solid-state batteries (ASSBs). These defects can alter the mechanical and electronic properties of solid electrolytes, with direct manifestations in the performance of ASSBs. Here, by building a library of 590 surfaces and grain boundaries of 11 relevant solid electrolytes—including halides, oxides, and sulfides— their electronic, mechanical, and thermodynamic characteristics are linked to the functional properties of polycrystalline solid electrolytes. It is found that the energy required to mechanically “separate” grain boundaries can be significantly lower than in the bulk region of materials, which can trigger preferential cracking of solid electrolyte particles in the grain boundary regions. The brittleness of ceramic solid electrolytes, inferred from the predicted low fracture toughness at the grain boundaries, contributes to their cracking under local pressure imparted by lithium (sodium) penetration in the grain boundaries. Extended defects of solid electrolytes introduce new electronic interfacial states within bandgaps of solid electrolytes. These states alter and possibly increase locally the availability of free electrons and holes in solid electrolytes. Factoring effects arising from extended defects appear crucial to explain electrochemical and mechanical observations in ASSBs.","electronic properties; first-principles calculations; grain boundaries; mechanical properties; solid electrolytes; surfaces","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:bd34c470-c2b0-40a3-bfbf-b3fdfa0c23b0","http://resolver.tudelft.nl/uuid:bd34c470-c2b0-40a3-bfbf-b3fdfa0c23b0","A retrofit sensing strategy for soft fluidic robots","Zou, Shibo (Institute for Atomic and Molecular Physics); Picella, Sergio (Institute for Atomic and Molecular Physics; Eindhoven University of Technology); de Vries, Jelle (Institute for Atomic and Molecular Physics); Kortman, V.G. (TU Delft Medical Instruments & Bio-Inspired Technology); Sakes, A. (TU Delft Medical Instruments & Bio-Inspired Technology); Overvelde, Johannes T.B. (Institute for Atomic and Molecular Physics; Eindhoven University of Technology)","","2024","Soft robots are intrinsically capable of adapting to different environments by changing their shape in response to interaction forces. However, sensory feedback is still required for higher level decisions. Most sensing technologies integrate separate sensing elements in soft actuators, which presents a considerable challenge for both the fabrication and robustness of soft robots. Here we present a versatile sensing strategy that can be retrofitted to existing soft fluidic devices without the need for design changes. We achieve this by measuring the fluidic input that is required to activate a soft actuator during interaction with the environment, and relating this input to its deformed state. We demonstrate the versatility of our strategy by tactile sensing of the size, shape, surface roughness and stiffness of objects. We furthermore retrofit sensing to a range of existing pneumatic soft actuators and grippers. Finally, we show the robustness of our fluidic sensing strategy in closed-loop control of a soft gripper for sorting, fruit picking and ripeness detection. We conclude that as long as the interaction of the actuator with the environment results in a shape change of the interval volume, soft fluidic actuators require no embedded sensors and design modifications to implement useful sensing.","","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:c450abb3-38bd-4f3b-9600-909b67c29d8a","http://resolver.tudelft.nl/uuid:c450abb3-38bd-4f3b-9600-909b67c29d8a","Anionic extracellular polymeric substances extracted from seawater-adapted aerobic granular sludge","Chen, L.M. (TU Delft BT/Environmental Biotechnology); Beck, Paula (Student TU Delft); van Ede, J.M. (TU Delft BT/Environmental Biotechnology); Pronk, M. (TU Delft BT/Environmental Biotechnology; Royal HaskoningDHV); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Lin, Y. (TU Delft Environmental Fluid Mechanics)","","2024","Abstract: Anionic polymers, such as heparin, have been widely applied in the chemical and medical fields, particularly for binding proteins (e.g., fibroblast growth factor 2 (FGF-2) and histones). However, the current animal-based production of heparin brings great risks, including resource shortages and product contamination. Recently, anionic compounds, nonulosonic acids (NulOs), and sulfated glycoconjugates were discovered in the extracellular polymeric substances (EPS) of aerobic granular sludge (AGS). Given the prevalence of anionic polymers, in marine biofilms, it was hypothesized that the EPS from AGS grown under seawater condition could serve as a raw material for producing the alternatives to heparin. This study aimed to isolate and enrich the anionic fractions of EPS and evaluate their potential application in the chemical and medical fields. The AGS was grown in a lab-scale reactor fed with acetate, under the seawater condition (35 g/L sea salt). The EPS was extracted with an alkaline solution at 80 °C and fractionated by size exclusion chromatography. Its protein binding capacity was evaluated by native gel electrophoresis. It was found that the two highest molecular weight fractions (438– > 14,320 kDa) were enriched with NulO and sulfate-containing glycoconjugates. The enriched fractions can strongly bind the two histones involved in sepsis and a model protein used for purification by heparin-column. These findings demonstrated possibilities for the application of the extracted EPS and open up a novel strategy for resource recovery. Key points: • High MW EPS from seawater-adapted AGS are dominant with sulfated groups and NulOs • Fifty-eight percent of the EPS is high MW of 68–14,320 kDa • EPS and its fractions can bind histones and fibroblast growth factor 2 Graphical Abstract: [Figure not available: see fulltext.]","EPS; Granular sludge; Nonulosonic acids; Protein binding; Sulfated glycoconjugates","en","journal article","","","","","","","","2024-07-17","","","BT/Environmental Biotechnology","","",""
"uuid:d2658035-ffdc-409f-a029-c64475a077ab","http://resolver.tudelft.nl/uuid:d2658035-ffdc-409f-a029-c64475a077ab","Towards interactive explanation-based nutrition virtual coaching systems","Buzcu, Berk (Özyeğin University; University of Applied Sciences and Arts Western Switzerland); Tessa, Melissa (High National School of Computer Science ESI ex-INI, Algiers); Tchappi, Igor (University of Luxembourg); Najjar, Amro (Luxembourg Institute of Science and Technology; University of Luxembourg); Hulstijn, Joris (University of Luxembourg); Calvaresi, Davide (University of Applied Sciences and Arts Western Switzerland); Aydoğan, Reyhan (TU Delft Interactive Intelligence; Özyeğin University; Universidad de Alcalá)","","2024","The awareness about healthy lifestyles is increasing, opening to personalized intelligent health coaching applications. A demand for more than mere suggestions and mechanistic interactions has driven attention to nutrition virtual coaching systems (NVC) as a bridge between human–machine interaction and recommender, informative, persuasive, and argumentation systems. NVC can rely on data-driven opaque mechanisms. Therefore, it is crucial to enable NVC to explain their doing (i.e., engaging the user in discussions (via arguments) about dietary solutions/alternatives). By doing so, transparency, user acceptance, and engagement are expected to be boosted. This study focuses on NVC agents generating personalized food recommendations based on user-specific factors such as allergies, eating habits, lifestyles, and ingredient preferences. In particular, we propose a user-agent negotiation process entailing run-time feedback mechanisms to react to both recommendations and related explanations. Lastly, the study presents the findings obtained by the experiments conducted with multi-background participants to evaluate the acceptability and effectiveness of the proposed system. The results indicate that most participants value the opportunity to provide feedback and receive explanations for recommendations. Additionally, the users are fond of receiving information tailored to their needs. Furthermore, our interactive recommendation system performed better than the corresponding traditional recommendation system in terms of effectiveness regarding the number of agreements and rounds.","Explainable AI; Interactive; Nutrition virtual coach; Recommender systems","en","journal article","","","","","","","","","","","Interactive Intelligence","","",""
"uuid:3178d527-9b0f-4996-8fcb-e324c74f9925","http://resolver.tudelft.nl/uuid:3178d527-9b0f-4996-8fcb-e324c74f9925","A real-world dataset of group emotion experiences based on physiological data","Bota, Patrícia (Instituto de Telecomunicações); Brito, Joana (Instituto de Telecomunicações); Fred, Ana (Instituto de Telecomunicações; Lisbon Technical University); Cesar, Pablo (TU Delft Multimedia Computing; Centrum Wiskunde & Informatica (CWI)); Silva, Hugo (Instituto de Telecomunicações)","","2024","Affective computing has experienced substantial advancements in recognizing emotions through image and facial expression analysis. However, the incorporation of physiological data remains constrained. Emotion recognition with physiological data shows promising results in controlled experiments but lacks generalization to real-world settings. To address this, we present G-REx, a dataset for real-world affective computing. We collected physiological data (photoplethysmography and electrodermal activity) using a wrist-worn device during long-duration movie sessions. Emotion annotations were retrospectively performed on segments with elevated physiological responses. The dataset includes over 31 movie sessions, totaling 380 h+ of data from 190+ subjects. The data were collected in a group setting, which can give further context to emotion recognition systems. Our setup aims to be easily replicable in any real-life scenario, facilitating the collection of large datasets for novel affective computing systems.","","en","journal article","","","","","","","","","","","Multimedia Computing","","",""
"uuid:0f97b7aa-151b-4060-97a0-c88849e9b3c2","http://resolver.tudelft.nl/uuid:0f97b7aa-151b-4060-97a0-c88849e9b3c2","Predicting willingness to pay and implement different rooftop strategies to characterize social perception of climate change mitigation and adaptation","Untereiner, Erin (Universitat Autònoma de Barcelona); Toboso Chavero, S.T.C.H. (TU Delft Integral Design & Management; Universitat Autònoma de Barcelona; Erasmus Universiteit Rotterdam); Fariñas, Ana Vázquez (Universitat Autònoma de Barcelona); Madrid-Lopez, Cristina (Universitat Autònoma de Barcelona); Villalba, Gara (Universitat Autònoma de Barcelona); Durany, Xavier Gabarrell (Universitat Autònoma de Barcelona)","","2024","With the latest IPCC report, dramatic global climate action must be taken immediately to limit global warming to 1.5 °C, or face more frequent and extreme weather events with catastrophic implications. Cities must invest in climate resilience development; however, government policies are only effective if they are supported by the society in which they serve. As such, this study aims to characterize the social perception of climate resilience development, in particular the implementation of sustainable urban rooftop strategies, to support policy makers and enable individual action. This was accomplished through the analysis of 1,100 answered surveys in Cerdanyola del Vallès (Spain), to assess one’s willingness to pay (WTP) and willingness to implement (WTI) rooftop strategies according to: 1. socio-demographical characteristics; 2. social perceptions and beliefs; and 3. surrounding land use and land cover, and vulnerabilities identified through temperature and normalized difference vegetation index (NDVI) maps. The results of this study found age played a significant role in predictability, with 18-39-year-olds being the most willing to pay and implement the various rooftop scenarios. However, our results uncovered societal inequality as those 85+ were the second group most interested in rooftop agriculture but the most financially restricted. Belief in the viability of rooftop strategies increased respondents WTP and WTI while having access to ones’ rooftop increased willingness to partake in rooftop food cultivation and enhance rooftop greenery. A new finding presented by this study is the quantifiable impact that urban greenery plays on increasing survey respondents WTP and WTI.","circular cities; public perception; socio-ecological systems; urban agriculture; urban ecology; urban green infrastructure","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:69f49e60-87d7-4f4e-aa8b-967c69a00277","http://resolver.tudelft.nl/uuid:69f49e60-87d7-4f4e-aa8b-967c69a00277","Dispersion and deformation of molecular patterns written in turbulent air","van de Water, W. (TU Delft Fluid Mechanics); Dam, Nico (Radboud Universiteit Nijmegen; Eindhoven University of Technology); Calzavarini, Enrico (Université de Lille)","","2024","Molecular tagging is used to study the dispersion and deformation of patterns written in turbulent air. The writing is done by fusing O2 and N2 molecules into NO in the focus of a strong ultraviolet laser beam. By crossing several of these laser beams, patterns that have both small and large scales can be painted. The patterns are visualized a while later by inducing fluorescence of the NO molecules with a second UV laser and registering the image. The width of the lines that make the pattern is approximately 50μm, a few times the Kolmogorov length η, the smallest length scale in turbulence, while the largest size of the patterns (≈4mm) is inside the inertial range of the used turbulent jet flow. At small scales molecular clouds disperse under the joint action of molecular diffusion and turbulence. The experiments reveal this highly nontrivial interaction. At inertial-range scales (≈200η) we verify the Batchelor dispersion of objects whose size is inside the inertial range. Patterns are compressible objects and spontaneously develop concentration fluctuations. We show for the first time the nontrivial statistical properties of these fluctuations. Finally, we use the information in written and deformed lines to quantify turbulent intermittency, obtaining results that agree with the established scaling anomaly of velocity structure functions.","","en","journal article","","","","","","","","","","","Fluid Mechanics","","",""
"uuid:8b123d4f-936e-41ca-b0a2-914262bc9df8","http://resolver.tudelft.nl/uuid:8b123d4f-936e-41ca-b0a2-914262bc9df8","Editorial: Smart condition assessment of railway infrastructure","Ribeiro, Diogo (Polytechnic of Porto); Calçada, Rui (Universidade do Porto); Roberts, Clive (University of Birmingham); Markine, V.L. (TU Delft Railway Engineering)","","2024","This editorial is referred to the Special Issue (SI) “Smart Condition Assessment of Railway Infrastructure” which aims to bring together the latest research studies, findings, and achievements regarding the smart condition assessment of railway infrastructure to prevent critical failure mechanisms. This SI counted with 20 high quality technical and scientific contributions involving 112 authors of 5 countries.","","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-11","","","Railway Engineering","","",""
"uuid:a30614f0-a4de-4403-b8be-2033add13679","http://resolver.tudelft.nl/uuid:a30614f0-a4de-4403-b8be-2033add13679","Development and experiment of an intelligent connected cooperative vehicle infrastructure system based on multiple V2I modes and BWM-IGR method","Li, Chunjie (Southeast University); Xu, Chengcheng (Southeast University); Chen, Y. (TU Delft Transport and Planning); Li, Zhibin (Southeast University)","","2024","To increase the efficiency and safety of expressway, this paper constructed a new intelligent connected cooperative vehicle infrastructure system and its effectiveness was verifid from both data and practical applications. Firstly, considering the convenience of using intelligent networking systems for public transportation, a new intelligent connected cooperative vehicle infrastructure system architecture was proposed by incorporating mobile communication methods. Then, the new system was illustrated from road side unit (RSU), on board unit (OBU) and data interaction. Additionally, to verify the effectiveness of the system, this paper proposes a two-stage model named Transformer Embedded Clustering- Hierarchical Density-Based Spatial Clustering of Applications with Noise (TEC-HDBSCAN) model to identify outliers in the trajectory data of vehicles collected by the system and obtain the speed sequence of the vehicle. Finally, data from actual testing scenarios was collected and a Best Worst Method-Improved Gray Relational (BWM-IGR) model was built to verify the effectiveness of the system. The results show that the established intelligent networked transportation system can effectively guide vehicles and collect data with high accuracy.","Abnormal data recognition; Comprehensive evaluation; Effectiveness testing; Intelligent connected cooperative vehicle infrastructure system","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-06","","","Transport and Planning","","",""
"uuid:76accbdf-6bc7-4841-ad12-39de813cdbb3","http://resolver.tudelft.nl/uuid:76accbdf-6bc7-4841-ad12-39de813cdbb3","Experimentally informed modeling of the early-age stress evolution in cementitious materials using exponential conversion from creep to relaxation","Liang, M. (TU Delft Materials and Environment); Luzio, Giovanni Di (Politecnico di Milano); Schlangen, E. (TU Delft Materials and Environment); Šavija, B. (TU Delft Materials and Environment)","","2024","This study presents comprehensive numerical modeling methods for simulating early-age stress (EAS) relaxation in cementitious materials, based on the autogenous deformation (AD), elastic modulus, creep, and stress continuously tested by a mini temperature stress testing machine (Mini-TSTM) and a mini AD testing machine from a very early age (i.e., from a few hours to a week). Four methods for converting creep compliance to relaxation modulus were discussed in detail and used for the one-dimensional (1D) and three-dimensional (3D) simulation of stress evolution in the Mini-TSTM test. Furthermore, virtual creep and relaxation tests were conducted using an exponential algorithm with either the Kelvin or Maxwell chains to show their applicability in simulating the viscoelastic behavior of early-age cementitious materials. The results showed that the exponential algorithm with the Maxwell chain using an exponential conversion function from creep to relaxation obtains good prediction accuracy of EAS in 3D analysis. The numerical solutions of the Volterra integral of creep compliance can lead to a negative relaxation modulus, thus introducing stress calculation errors in both 1D and 3D analysis.","","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:414f6c87-d627-4054-8023-bbb2fd5dc9b5","http://resolver.tudelft.nl/uuid:414f6c87-d627-4054-8023-bbb2fd5dc9b5","The use of additive manufacturing in self-healing cementitious materials: A state-of-the-art review","Wan, Z. (TU Delft Materials and Environment); Xu, Y. (TU Delft Materials and Environment); He, S. (TU Delft Materials and Environment); Schlangen, E. (TU Delft Materials and Environment); Šavija, B. (TU Delft Materials and Environment)","","2024","This paper presents a state-of-the-art review on the application of additive manufacturing (AM) in self-healing cementitious materials. AM has been utilized in self-healing cementitious materials in three ways: (1) concrete with 3D-printed capsules/vasculatures; (2) 3D concrete printing (3DCP) with fibers or supplementary cementitious materials (SCMs); and (3) a combination of (1) and (2). 3D-printed capsules/vascular systems are the most extensively investigated, which are capable of housing larger volumes of healing agents. However, due to the dimension restraints of printers, most of the printed vasculatures/capsules are in small scale, making them difficult for upscaling. Meanwhile, 3DCP shows great potential to lower the environmental footprint of concrete construction. Incorporation of fibers and SCMs helps improve the autogenous healing performance of 3DCP. Besides, 3D-printed concrete with hollow channels as the vasculature could further improve the autonomous healing and scalability of self-healing cementitious materials. Finally, possible directions for future research are discussed.","3D concrete printing; Additive manufacturing; Capsule; Self-healing cementitious materials; Vascular system","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:f06e8f3c-895d-4cf2-b4df-327543c98cb0","http://resolver.tudelft.nl/uuid:f06e8f3c-895d-4cf2-b4df-327543c98cb0","An adaptive route choice model for integrated fixed and flexible transit systems","Leffler, David (KTH Royal Institute of Technology); Burghout, Wilco (KTH Royal Institute of Technology); Cats, O. (TU Delft Transport and Planning; KTH Royal Institute of Technology); Jenelius, Erik (KTH Royal Institute of Technology)","","2024","Over the past decade, there has been a surge of interest in the application of agent-based simulation models to evaluate flexible transit solutions characterized by different degrees of short-term flexibility in routing and scheduling. A central modelling decision in the development is how one chooses to represent the mode- and route-choices of travellers. The real-time adaptive behaviour of travellers is important to model in the presence of a flexible transit service, where the routing and scheduling of vehicles is highly dependent on supply-demand dynamics at a near real-time temporal resolution. We propose a utility-based transit route-choice model with representation of within-day adaptive travel behaviour and between-day learning where station-based fixed-transit, flexible-transit, and active-mode alternatives may be dynamically combined in a single path. To enable experimentation, this route-choice model is implemented within an agent-based dynamic public transit simulation framework. We first explore model properties in a choice between fixed- and flexible-transit modes for a toy network. The adaptive route choice framework is then applied to a case study based on a real-life branched transit service in Stockholm, Sweden. This case study illustrates level-of-service trade-offs, in terms of waiting times and in-vehicle times, between passenger groups and analyzes traveller mode choices within a mixed fixed- and flexible transit system. Results show that the proposed framework is capable of capturing dynamic route choices in mixed flexible and fixed transit systems and that the day-to-day learning model leads to stable fixed-flexible mode choices.","agent-based simulation; flexible transit; Public transit; route choice; transit assignment","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:7673786b-4af7-4299-9339-cfc3a3657972","http://resolver.tudelft.nl/uuid:7673786b-4af7-4299-9339-cfc3a3657972","Investigation of non-ideal effects in compressible boundary layers of dense vapors through direct numerical simulations","Tosto, F. (TU Delft Flight Performance and Propulsion); Wheeler, Andrew (University of Cambridge); Pini, M. (TU Delft Flight Performance and Propulsion)","","2024","In this work, we present an investigation about the sources of dissipation in adiabatic boundary layers of non-ideal compressible fluid flows. Direct numerical simulations (DNS) of transitional, zero-pressure gradient boundary layer flows are performed for two fluids characterized by different complexity of the fluid molecules, namely, “air” and siloxane MM. Different sets of thermodynamic free-stream boundary conditions are selected to evaluate the influence of the fluid state on both the frictional loss and the dissipation mechanisms. The thermophysical properties of siloxane MM are calculated with a state-of-the-art equation of state. Results show that the dissipation due to both time-mean strain field, irreversible heat transfer, and turbulent dissipation differs significantly depending on both the molecular complexity of the fluid and its thermodynamic state. The dissipation coefficient calculated from the DNS results is then compared against the one obtained using a reduced-order model (ROM), which solves the two-dimensional boundary layer flow equations for an arbitrary fluid [M. Pini and C. De Servi, “Entropy generation in laminar boundary layers of non-ideal fluid flows,” in 2nd International Seminar on Non-Ideal Compressible Fluid Dynamics for Propulsion and Power (Springer, 2020), pp. 104-117]. Results from both the DNS and the ROM show that low values of the overall dissipation are observed in the case of fluids made of simple molecules, e.g., air, and if the fluid is at a thermodynamic state in the proximity of that of the vapor-liquid critical point.","","en","journal article","","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:74e721e7-c964-4100-9061-c7c3ddbfa873","http://resolver.tudelft.nl/uuid:74e721e7-c964-4100-9061-c7c3ddbfa873","Numerical modelling and quantification of coastal urban compound flooding","Yuan, Jiao (Zhejiang University); Zheng, Feifei (Zhejiang University); Duan, Huan Feng (The Hong Kong Polytechnic University); Deng, Zhengzhi (Zhejiang University); Kapelan, Z. (TU Delft Sanitary Engineering); Savic, Dragan (KWR Water Research Institute; University of Exeter; University of Belgrade); Shao, Tan (Guangdong Hydrological Bureau); Huang, Wei Min (Guangdong Hydrological Bureau); Zhao, Tongtiegang (Sun Yat-sen University); Chen, Xiaohong (Sun Yat-sen University)","","2024","Low-lying coastal cities are vulnerable to compound floods caused by many factors including river flows, tides and local rainfall. Many previous studies focus on the impacts of rainfall and tidal levels (two driving factors) on estuaries or regions near the main single river, while research about the three influencing factors on the floods for complex urban river networks remain relatively scarce. This paper proposes a framework to simulate the coastal compound flooding process, with a series of scenarios designed to explore the main flooding drivers and their worst possible combination. The approach is used to quantify the induced flooding consequences, in which a two-dimensional model is employed to conduct a case study for a city with complex river networks. The Qianshan River basin in Zhuhai City, located in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) of China is used as the case study. Application results show that: (i) the occurrence and properties of flooding in this coastal area are jointly affected by upstream river flows, downstream tidal levels and local rainfall intensity with different contribution levels, (ii) compared to tidal levels, local rainfall intensity has a larger impact on the flooding levels of the study region, and (iii) the worst scenario where a 50-year return period upstream river flow co-occurring with high tide and a 100-year return period rainfall can produce a flooding area up to 50 km2 for the study region, with an average of 1.3 m flooded depth. The proposed framework with its findings offers an in-depth understanding and quantification of coastal urban flood characteristics within the GBA of China.","Complex river network; Compound flooding; Numerical modelling; Scenario analysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-26","","","Sanitary Engineering","","",""
"uuid:a97d32fe-e891-4424-a238-4916a7254d5a","http://resolver.tudelft.nl/uuid:a97d32fe-e891-4424-a238-4916a7254d5a","Structural evolution of calcium sodium aluminosilicate hydrate (C-(N-)A-S-H) gels induced by water exposure: The impact of Na leaching","Liu, C. (TU Delft Materials and Environment); Li, Zhenming (Harbin Institute of Technology; University of Sheffield); Nie, Shuai (Aarhus University); Skibsted, Jørgen (Aarhus University); Ye, G. (TU Delft Materials and Environment)","","2024","Calcium sodium aluminosilicate hydrate C-(N-)A-S-H gels, formed through the alkali-activation of calcium silicate-based materials, may exhibit greater susceptibility to aqueous environments when compared to traditional C-(A-)S-H phases formed by hydration of blended Portland cements. This study investigates structural changes in synthesized C-(N-)A-S-H gels triggered by water immersion. Three gels have been examined, each with stoichiometrically controlled ratios of Ca/Si (0.8 and 1.2), Al/Si (0.1 and 0.3), and Na/Si (0.1, 0.2, and 0.3). The gel with a higher Ca/Si ratio demonstrated enhanced resistance to water leaching and only experienced marginal decalcification whereas the gels with lower Ca/Si ratios exhibited more pronounced effects including leaching losses of Si. Notably, all gels displayed rapid and substantial sodium leaching, contributing to an increased degree of polymerization for the aluminosilicate tetrahedra in the gels. A plausible mechanism for this change is that Na leaches out from the interlayer and Ca ions progressively take over the role of charge compensators in the interlayer of the C-(N-)A-S-H structure.","Na, Al and Si NMR; C-(N-)A-S-H gel; Leaching; Structural evolution; Water immersion","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-28","","","Materials and Environment","","",""
"uuid:6f94c28c-fbae-458e-a757-6331d1561b25","http://resolver.tudelft.nl/uuid:6f94c28c-fbae-458e-a757-6331d1561b25","Incorporating strontium enriched amorphous calcium phosphate granules in collagen/collagen-magnesium-hydroxyapatite osteochondral scaffolds improves subchondral bone repair","Xu, J. (Erasmus MC); Vecstaudza, Jana (Riga Technical University); Wesdorp, Marinus A. (Erasmus MC); Labberté, Margot (University College Dublin); Salerno, Manuela (Rizzoli Orthopaedic Institute); Kok, Joeri (Eindhoven University of Technology); van Rietbergen, Bert (Eindhoven University of Technology); van Osch, G.J.V.M. (TU Delft Biomaterials & Tissue Biomechanics; Erasmus MC); Locs, Janis (Riga Technical University); Brama, Pieter A.J. (University College Dublin)","","2024","Osteochondral defect repair with a collagen/collagen-magnesium-hydroxyapatite (Col/Col-Mg-HAp) scaffold has demonstrated good clinical results. However, subchondral bone repair remained suboptimal, potentially leading to damage to the regenerated overlying neocartilage. This study aimed to improve the bone repair potential of this scaffold by incorporating newly developed strontium (Sr) ion enriched amorphous calcium phosphate (Sr-ACP) granules (100–150 μm). Sr concentration of Sr-ACP was determined with ICP-MS at 2.49 ± 0.04 wt%. Then 30 wt% ACP or Sr-ACP granules were integrated into the scaffold prototypes. The ACP or Sr-ACP granules were well embedded and distributed in the collagen matrix demonstrated by micro-CT and scanning electron microscopy/energy dispersive x-ray spectrometry. Good cytocompatibility of ACP/Sr-ACP granules and ACP/Sr-ACP enriched scaffolds was confirmed with in vitro cytotoxicity assays. An overall promising early tissue response and good biocompatibility of ACP and Sr-ACP enriched scaffolds were demonstrated in a subcutaneous mouse model. In a goat osteochondral defect model, significantly more bone was observed at 6 months with the treatment of Sr-ACP enriched scaffolds compared to scaffold-only, in particular in the weight-bearing femoral condyle subchondral bone defect. Overall, the incorporation of osteogenic Sr-ACP granules in Col/Col-Mg-HAp scaffolds showed to be a feasible and promising strategy to improve subchondral bone repair.","Amorphous calcium phosphate; Osteochondral defect; Regenerative medicine; Strontium; Tissue engineering","en","journal article","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:9d8a7d78-d2a6-4575-ba47-2d41516d4ff6","http://resolver.tudelft.nl/uuid:9d8a7d78-d2a6-4575-ba47-2d41516d4ff6","Handling uncertainty in train timetable rescheduling: A review of the literature and future research directions","Zhan, Shuguang (Hefei University of Technology); Xie, Jiemin (Sun Yat-sen University); Wong, S. C. (The University of Hong Kong); Zhu, Y. (TU Delft Transport and Planning; ETH Zürich); Corman, Francesco (ETH Zürich)","","2024","External and internal factors can cause disturbances or disruptions in daily train operations, leading to deviations from official timetables and passenger delays. As a result, efficient train timetable rescheduling (TTR) methods are necessary to restore disrupted train services. Although TTR has been a popular research topic in recent years, the uncertain characteristics of railways have not been sufficiently addressed. This review first identifies the primary uncertainties of TTR and examines their impacts on both TTR and passenger routing during disturbances or disruptions. It finds that only a few uncertainties have been investigated, and the existing solution methods do not adequately meet practical requirements, such as considering the dynamic nature of disturbances or disruptions, which is crucial for real-world applications. Therefore, the review highlights problems associated with TTR uncertainties that need urgent attention and suggests promising methodologies that could effectively address these issues as future research directions. This review aims to help practitioners develop improved automatic train-dispatching systems with better train-rescheduling performance under disturbances or disruptions compared to current systems.","Disruption management; Railways; Stochastic perturbation; Train timetable rescheduling","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:01775ed6-97c1-4264-9ec8-a686e195a771","http://resolver.tudelft.nl/uuid:01775ed6-97c1-4264-9ec8-a686e195a771","A versatile in situ cofactor enhancing system for meeting cellular demands for engineered metabolic pathways","Jaroensuk, Juthamas (Vidyasirimedhi Institute of Science and Technology); Sutthaphirom, Chalermroj (Vidyasirimedhi Institute of Science and Technology); Phonbuppha, Jittima (Vidyasirimedhi Institute of Science and Technology); Chinantuya, Wachirawit (Vidyasirimedhi Institute of Science and Technology; Mahidol University); Kesornpun, Chatchai (Vidyasirimedhi Institute of Science and Technology); Akeratchatapan, Nattanon (Vidyasirimedhi Institute of Science and Technology); Kittipanukul, Narongyot (Vidyasirimedhi Institute of Science and Technology); Phatinuwat, Kamonwan (Chulabhorn Graduate Institute, Bangkok); Hollmann, F. (TU Delft BT/Biocatalysis)","","2024","Cofactor imbalance obstructs the productivities of metabolically engineered cells. Herein, we employed a minimally perturbing system, xylose reductase and lactose (XR/lactose), to increase the levels of a pool of sugar phosphates which are connected to the biosynthesis of NAD(P)H, FAD, FMN, and ATP in Escherichia coli. The XR/lactose system could increase the amounts of the precursors of these cofactors and was tested with three different metabolically engineered cell systems (fatty alcohol biosynthesis, bioluminescence light generation, and alkane biosynthesis) with different cofactor demands. Productivities of these cells were increased 2-4-fold by the XR/lactose system. Untargeted metabolomic analysis revealed different metabolite patterns among these cells, demonstrating that only metabolites involved in relevant cofactor biosynthesis were altered. The results were also confirmed by transcriptomic analysis. Another sugar reducing system (glucose dehydrogenase) could also be used to increase fatty alcohol production but resulted in less yield enhancement than XR. This work demonstrates that the approach of increasing cellular sugar phosphates can be a generic tool to increase in vivo cofactor generation upon cellular demand for synthetic biology.","alkane; bioluminescence; fatty alcohol; metabolic engineering; sugar phosphate; synthetic biology; xylose reductase","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:a1fb547a-c028-405f-a402-47c0fd8a4273","http://resolver.tudelft.nl/uuid:a1fb547a-c028-405f-a402-47c0fd8a4273","Scaling ice-induced vibrations by combining replica modeling and preservation of kinematics","Hammer, T.C. (TU Delft Offshore Engineering); Puolakka, Otto (Aalto University); Hendrikse, H. (TU Delft Offshore Engineering)","","2024","A modeling approach to simulate ice-induced vibrations of vertically sided offshore structures in ice tank experiments is presented. The technique combines replica modeling with the preservation of kinematics during ice-structure interaction. The technique was chosen based on the theoretical understanding that ice-induced vibrations are caused by an energy exchange between the structure and the ice. The mechanism is controlled by primarily four aspects: the kinematics during ice-structure interaction, the degree to which the ice can resist higher loading at low velocities prior to failure (velocity effect), the existence of a transition speed from ductile-to-brittle failure, and the mean ice load level. A model ice type which resulted in a velocity effect and provided a transition speed comparable to that of sea ice was developed and used during ice tank experiments. A scaling factor, derived from the comparison between the mean brittle crushing ice load of the full-scale event and the in-situ measured mean brittle crushing model ice load, was applied to scale structure properties of a numerical model. This model was implemented during real-time hybrid simulations in model ice to preserve kinematics during the ice-structure interaction. To verify the proposed scaling approach, rigid indenter experiments covering velocities from 0.1 mm s−1 to 500 mm s−1 and dynamic ice-induced vibration experiments of structures with varying aspect ratios (8 and 12) and shapes (cylindrical and rectangular) were conducted. Neither the aspect ratio nor shape appeared to influence the development of ice-induced vibrations significantly. The approach was qualitatively validated by reproducing full-scale ice-induced vibrations as experienced by the Molikpaq platform and Norströmsgrund lighthouse.","Crushing; Hybrid test setup; Ice tank experiments; Model tests; Offshore structures","en","journal article","","","","","","","","","","","Offshore Engineering","","",""
"uuid:a59f944e-3bd9-47a8-a739-01cd9c97b757","http://resolver.tudelft.nl/uuid:a59f944e-3bd9-47a8-a739-01cd9c97b757","Limitations of a biokinetic model to predict the seasonal variations of nitrous oxide emissions from a full-scale wastewater treatment plant","Seshan, S. (TU Delft Sanitary Engineering; KWR Water Research Institute); Poinapen, Johann (KWR Water Research Institute); Zandvoort, Marcel H. (Waternet); van Lier, J.B. (TU Delft Sanitary Engineering); Kapelan, Z. (TU Delft Sanitary Engineering)","","2024","A biokinetic model based on BioWin's Activated Sludge Digestion Model (ASDM) coupled with a nitrous oxide (N2O) model was setup and calibrated for a full-scale wastewater treatment plant (WWTP) Amsterdam West, in the Netherlands. The model was calibrated using one year of continuous data to predict the seasonal variations of N2O emissions in the gaseous phase. This, according to our best knowledge, is the most complete full-scale data set used to date for this purpose. The results obtained suggest that the currently available biokinetic model predicted the winter, summer, and autumn N2O emissions well but failed to satisfactorily simulate the spring peak. During the calibration process, it was found that the nitrifier denitrification pathway could explain the observed emissions during all seasons while a combination of the nitrifier denitrification and incomplete heterotrophic denitrification pathways seemed to be dominant during the emissions peak observed during the spring season. Specifically, kinetic parameters related to free nitrous acid (FNA) displayed significant sensitivity leading to increased N2O production. The obtained values of two kinetic parameters, i.e., the FNA half-saturation during ammonia oxidising bacteria (AOB) denitrification and the FNA inhibition concentration related to heterotrophic denitrification, suggested a strong influence of the FNA bulk concentration on the N2O emissions and the observed seasonal variations. Based on the suboptimal performance and limitations of the biokinetic model, further research is needed to better understand the biochemical processes behind the seasonal peak and the influence of FNA.","Biokinetic modelling; Free nitrous acid; Nitrous oxide; Production pathways; Seasonal variations","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:40986389-2340-4a5f-b8e9-e74cf5e24ccd","http://resolver.tudelft.nl/uuid:40986389-2340-4a5f-b8e9-e74cf5e24ccd","Precursory Signals to Injection Induced Fault Reactivation in the Laboratory Using Active Ultrasonic Monitoring Methods","Veltmeijer, A.V. (TU Delft Applied Geophysics and Petrophysics); Naderloo, M. (TU Delft Reservoir Engineering); Pluymakers, Anne (TU Delft Applied Geophysics and Petrophysics); Barnhoorn, A. (TU Delft Applied Geophysics and Petrophysics)","","2024","Induced earthquakes are still highly unpredictable, and often caused by variations in pore fluid pressure. Monitoring and understanding the mechanisms of fluid-induced fault slip is essential for seismic risk mitigation and seismicity forecasting. Fluid-induced slip experiments were performed on critically stressed faulted sandstone samples, and the evolution of the actively sent ultrasonic waves throughout the experiment was measured. Two different fault types were used: smooth saw-cut fault samples at a 35° angle, and a rough fault created by in situ faulting of the samples. Variations in the seismic slip velocity and friction along the fault plane were identified by the coda of the ultrasonic waves. Additionally, ultrasonic amplitudes show precursory signals to laboratory fault reactivation. Our results show that small and local variations in stress before fault failure can be inferred using coda wave interferometry for time-lapse monitoring, as coda waves are more sensitive to small perturbations in a medium than direct waves. Hence, these signals can be used as precursors to laboratory fault slip and to give insight into reactivation mechanisms. Our results show that time-lapse monitoring of coda waves can be used to monitor local stress changes associated with fault reactivation in this laboratory setting of fluid-induced fault reactivation. This is a critical first step toward a method for continuous monitoring of natural fault zones, contributing to seismic risk mitigation of induced and natural earthquakes.","coda wave interferometry; fault mechanics; injection-induced seismicity; ultrasonic monitoring","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:ff86bb56-92b5-4ea4-ad79-aeb194dab0ce","http://resolver.tudelft.nl/uuid:ff86bb56-92b5-4ea4-ad79-aeb194dab0ce","Influence of Peripheral Alkyl Groups on Junction Configurations in Single-Molecule Electronics","Ornago, L. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Zwick, Patrick (University of Basel); van der Poel, S. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Brandl, Thomas (University of Basel); El Abbassi, M. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Perrin, Mickael L. (ETH Zürich); Dulić, Diana (Universidad de Chile); van der Zant, H.S.J. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Mayor, Marcel (University of Basel; Karlsruhe Institut für Technologie; Sun Yat-sen University)","","2024","The addition of a lateral alkyl chain is a well-known strategy to reduce π-stacked ensembles of molecules in solution, with the intention to minimize the interactions between the molecules’ backbones. In this paper, we study whether this concept generalizes to single-molecule junctions by using a combination of mechanically controllable break junction (MCBJ) measurements and clustering-based data analysis with two small series of model compounds decorated with various bulky groups. The systematic study suggests that introducing alkyl side chains also favors the formation of electrode-molecule configurations that are not observed in their absence, thereby inducing broadening of the conductance peak in the one-dimensional histograms. Thus, the introduction of alkyl chains in aromatic compounds for molecular electronics must be carefully designed and optimized for the specific purpose, balancing between increased solubility and the possibility of additional junction configurations.","","en","journal article","","","","","","","","","","","QN/van der Zant Lab","","",""
"uuid:d62eeec3-6eac-4465-9302-ecbf8af35f03","http://resolver.tudelft.nl/uuid:d62eeec3-6eac-4465-9302-ecbf8af35f03","Precision and bias in dynamic light scattering optical coherence tomography measurements of diffusion and flow","Cheishvili, K. (TU Delft ImPhys/Kalkman group); Rieger, B. (TU Delft ImPhys/Computational Imaging; TU Delft ImPhys/Rieger group); Kalkman, J. (TU Delft ImPhys/Computational Imaging; TU Delft ImPhys/Kalkman group)","","2024","We quantify the precision and bias of dynamic light scattering optical coherence tomography (DLS-OCT) measurements of the diffusion coefficient and flow speed for first and second-order normalized autocovariance functions. For both diffusion and flow, the measurement precision and accuracy are severely limited by correlations between the errors in the normalized autocovariance function. We demonstrate a method of mixing statistically independent normalized autocovariance functions at every time delay for removing these correlations. The mixing method reduces the uncertainty in the obtained parameters by a factor of two but has no effect on the standard error of the mean. We find that the precision in DLS-OCT is identical for different averaging techniques but that the lowest bias is obtained by averaging the measured correlation functions before fitting the model parameters. With our correlation mixing method, it is possible to quantify the precision in DLS-OCT and verify whether the Cramer-Rao bound is reached.","","en","journal article","","","","","","","","","","","ImPhys/Kalkman group","","",""
"uuid:a33618f1-35f0-4a33-8a2c-0e2657f5b40c","http://resolver.tudelft.nl/uuid:a33618f1-35f0-4a33-8a2c-0e2657f5b40c","A new Bayesian approach for managing bathing water quality at river bathing locations vulnerable to short-term pollution","Seis, W.A.A. (TU Delft Sanitary Engineering; Kompetenzzentrum Wasser Berlin); ten Veldhuis, Marie-claire (TU Delft Water Resources); Rouault, Pascale (Kompetenzzentrum Wasser Berlin); Steffelbauer, D.B. (Kompetenzzentrum Wasser Berlin); Medema, G.J. (TU Delft Sanitary Engineering; KWR Water Research Institute)","","2024","Short-term fecal pollution events are a major challenge for managing microbial safety at recreational waters. Long turn-over times of current laboratory methods for analyzing fecal indicator bacteria (FIB) delay water quality assessments. Data-driven models have been shown to be valuable approaches to enable fast water quality assessments. However, a major barrier towards the wider use of such models is the prevalent data scarcity at existing bathing waters, which questions the representativeness and thus usefulness of such datasets for model training. The present study explores the ability of five data-driven modelling approaches to predict short-term fecal pollution episodes at recreational bathing locations under data scarce situations and imbalanced datasets. The study explicitly focuses on the potential benefits of adopting an innovative modeling and risk-based assessment approach, based on state/cluster-based Bayesian updating of FIB distributions in relation to different hydrological states. The models are benchmarked against commonly applied supervised learning approaches, particularly linear regression, and random forests, as well as to a zero-model which closely resembles the current way of classifying bathing water quality in the European Union. For model-based clustering we apply a non-parametric Bayesian approach based on a Dirichlet Process Mixture Model. The study tests and demonstrates the proposed approaches at three river bathing locations in Germany, known to be influenced by short-term pollution events. At each river two modelling experiments (“longest dry period”, “sequential model training”) are performed to explore how the different modelling approaches react and adapt to scarce and uninformative training data, i.e., datasets that do not include event pollution information in terms of elevated FIB concentrations. We demonstrate that it is especially the proposed Bayesian approaches that are able to raise correct warnings in such situations (> 90 % true positive rate). The zero-model and random forest are shown to be unable to predict contamination episodes if pollution episodes are not present in the training data. Our research shows that the investigated Bayesian approaches reduce the risk of missed pollution events, thereby improving bathing water safety management. Additionally, the approaches provide a transparent solution for setting minimum data quality requirements under various conditions. The proposed approaches open the way for developing data-driven models for bathing water quality prediction against the reality that data scarcity is common problem at existing and prospective bathing waters.","Dirichlet Process Mixture Model; Probabilistic modelling; Recreational waters","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:4b85c22f-4ed0-4fe1-a137-b064a60b0768","http://resolver.tudelft.nl/uuid:4b85c22f-4ed0-4fe1-a137-b064a60b0768","Adsorption characteristics and mechanisms of water-soluble polymers (PVP and PEG) on kaolin and montmorillonite minerals","Wang, Xintu (Guilin University of Technology; Chinese Academy of Sciences); Xu, Yanghui (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Ou, Q. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Chen, Wenwen (Guilin University of Technology); van der Meer, W.G.J. (University of Twente; Oasen); Liu, G. (TU Delft Sanitary Engineering; Chinese Academy of Sciences; University of Chinese Academy of Sciences)","","2024","The excessive use and accumulation of water-soluble polymers (WSPs, known as “liquid plastics”) in the environment can pose potential risks to both ecosystems and human health, but the environmental fate of WSPs remains unclear. Here, the adsorption behavior of WSPs with different molecular weight on kaolinite (Kaol) and montmorillonite (Mt) were examined. The results showed that the adsorption of PEG and PVP on minerals were controlled by hydrogen bond and van der Waals force. The Fourier transform infrared (FTIR) spectra and two-dimensional correlation spectroscopy (2D-COS) analysis revealed that there were interactions between the Al-O and Si-O groups of the minerals and the polar O- or N-containing functional groups as well as the alkyl groups of PEG and PVP. The adsorption characteristics of WSPs were closely related to their molecular weight and the pore size of minerals. Due to the relatively large mesopore size of Kaol, both PEG and PVP were absorbed into inner spaces, for which the adsorption capacity increased with molecular weight of the polymers. For Mt, all types of PEG could enter its micropores, while PVP with larger molecular weights appeared to be confined externally, leading to a decrease in the adsorption capacity of PVP with increasing molecular weight. The findings of this study provide a theoretical basis for scientific evaluation of environmental processes of WSPs.","Adsorption; Hydrogen bond; Minerals; Molecular weight; Water-soluble polymers","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:939f4600-e00b-49eb-9820-a96134b3f765","http://resolver.tudelft.nl/uuid:939f4600-e00b-49eb-9820-a96134b3f765","Experimental study on drag coefficient of flexible vegetation under non-breaking waves","Reis, Rui A. (Lisbon Technical University; National Laboratory of Civil Engineering (LNEC)); Fortes, Conceição J.E.M. (National Laboratory of Civil Engineering (LNEC)); Rodrigues, José A. (Instituto Politécnico de Lisboa; CIMA); Hu, Zhan (Sun Yat-sen University; Ministry of Education, Zhuhai; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)); Suzuki, T. (TU Delft Environmental Fluid Mechanics; Flanders Hydraulics Research)","","2024","Laboratory experiments of wave propagation over rigid and flexible vegetation fields, with the same configurations, were conducted to understand the effect of vegetation flexibility on the drag coefficient (CD). The direct method and the least squares method (LSM), based on force and flow measurements, are applied to calculate the CD in the experimental conditions. The formulations of both methods are extended to estimate the CD for flexible vegetation cases. A video analysis was performed to account for the swaying motion. Typically, wave dissipation is lower for flexible than for rigid vegetation of the same configuration, under the same flow condition. Therefore, a proportional effect in the corresponding CD results, obtained from common CD calibration to wave dissipation without considering vegetation motion, is usually observed. However, the present results show that although the wave dissipation was 34% lower for flexible relative to rigid vegetation, the respective CD values were close. CD estimations considering vegetation motion and inertia suggest that CD of flexible vegetation was up to 13% higher relative to rigid vegetation. Accounting for inertia reduced the CD for rigid vegetation up to 7%, while raised the CD for flexible vegetation up to 13%.","Drag coefficient; Flexible vegetation; Inertia; Vegetation motion; Wave dissipation","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:fe4e08a8-628d-422b-9c71-25d5c4366c17","http://resolver.tudelft.nl/uuid:fe4e08a8-628d-422b-9c71-25d5c4366c17","Bichromatic Rabi Control of Semiconductor Qubits","John, V. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); Borsoi, F. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); György, Zoltán (Eötvös University); Wang, C.A. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); Széchenyi, Gábor (Eötvös University); van Riggelen, F. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); Lawrie, W.I.L. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); Hendrickx, N.W. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); Sammak, A. (TU Delft BUS/TNO STAFF; QuTech); Scappucci, G. (TU Delft QCD/Scappucci Lab; Kavli institute of nanoscience Delft; QuTech); Pályi, András (Budapest University of Technology and Economics); Veldhorst, M. (TU Delft QN/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech)","","2024","Electrically driven spin resonance is a powerful technique for controlling semiconductor spin qubits. However, it faces challenges in qubit addressability and off-resonance driving in larger systems. We demonstrate coherent bichromatic Rabi control of quantum dot hole spin qubits, offering a spatially selective approach for large qubit arrays. By applying simultaneous microwave bursts to different gate electrodes, we observe multichromatic resonance lines and resonance anticrossings that are caused by the ac Stark shift. Our theoretical framework aligns with experimental data, highlighting interdot motion as the dominant mechanism for bichromatic driving.","","en","journal article","","","","","","","","","","","QCD/Veldhorst Lab","","",""
"uuid:fdc7c6ef-1cbf-4af0-84ff-6053b719b87a","http://resolver.tudelft.nl/uuid:fdc7c6ef-1cbf-4af0-84ff-6053b719b87a","State-of-the-art of Longitudinal Travel Surveys - A Comparison of the MOP and MPN","De Haas, Mathijs (KiM Netherlands Institute for Transport Policy Analysis); Ecke, Lisa (Karlsruhe Institut für Technologie); Chlond, Bastian (Karlsruhe Institut für Technologie); Hoogendoorn-Lanser, S. (TU Delft Corporate Innovations); Vortisch, Peter (Karlsruhe Institut für Technologie)","","2024","Longitudinal travel surveys are needed to capture individual travel behaviour changes. Only two longitudinal tavel surveys of national relevance are currently in operation, the German Mobility Panel (MOP) since 1994 and the Netherlands Mobility Panel (MPN) since 2013. This paper provides an overview of both panels' differences and similarities in design and data collection. Furthermore, representativeness, diary fatigue and non-random attrition are assessed in both panels to show the challenges panel surveys have to deal with. Overall, this paper shows important aspects of a panel survey that should be considered when designing a new longitudinal travel survey.","Data collection; German Mobility Panel (MOP); Longitudinal travel survey; Netherlands Mobility Panel (MPN); Panel data; Travel behaviour","en","journal article","","","","","","","","","","","Corporate Innovations","","",""
"uuid:916e8ee4-3025-4cb7-b80b-6e14f6b6a1ae","http://resolver.tudelft.nl/uuid:916e8ee4-3025-4cb7-b80b-6e14f6b6a1ae","The effect of micromechanical stresses on vacancy formation and stress-driven mass-transport in polycrystalline Fe–Au alloy","Hussein, Abdelrahman (Universiteit Gent; Korea University); van der Zwaag, S. (TU Delft Group Garcia Espallargas); Kim, Byungki (Korea University)","","2024","In recent years, a new class of super saturated binary and ternary alloys have demonstrated the ability for the self-healing of creep-induced voids formed at the grain boundaries. However, a clear understanding of the parameters affecting the self-healing mechanism is still not yet complete. One of the main challenges is understanding the effect of microstructure and micromechanical stresses on the redistribution of the healing-solute and vacancies. To this end, we address this issue using a CALPHAD-informed diffusion model coupled with crystal plasticity. In principle, the approach is general and can be used for any binary Fe–X alloy, but in this work Fe–Au binary system is used since it experimentally showed the best healing efficiency. First, we present a multicomponent diffusion model considering cross and stress-driven diffusion. The effect of stress was also considered on the equilibrium vacancy concentration. To investigate the effect of the micromechanical stresses, a representative volume element (RVE) was obtained using the phase-field method. The results showed that the maximum vacancy concentration is at the grain boundaries (GBs) with the highest hydrostatic tensile stresses. These were also the regions of the highest Au enrichment. A crucial factor to achieve this is the high diffusivity of Au compared to the Fe matrix. Increasing the stresses, lead to an increase both in vacancy and Au concentration. The accompanying increased stress triaxiality is suggested to be the reason for the reduced self-healing efficiency observed in previous experimental studies.","CALPHAD; Creep-voids; Cross diffusion; Crystal plasticity; Self-healing; Vacancies","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-01","","","Group Garcia Espallargas","","",""
"uuid:cb6307f0-68a4-49b4-82e6-cb63fa6d143c","http://resolver.tudelft.nl/uuid:cb6307f0-68a4-49b4-82e6-cb63fa6d143c","Functional grading of low alloy steel to 316 L by wire arc additive manufacturing – Microstructural and mechanical characterization of bi-metal interface","Galán Argumedo, J.L. (TU Delft Team Vera Popovich); Mahmoudiniya, M. (Universiteit Gent); Reinton, T.E. (TU Delft Team Vera Popovich); Kestens, L.A.I. (TU Delft Team Maria Santofimia Navarro; Universiteit Gent); Hermans, M.J.M. (TU Delft Team Marcel Hermans); Popovich, V. (TU Delft Team Vera Popovich)","","2024","This study examines the interface layer between a high-strength low-alloy steel and an overlaying austenitic stainless steel as deposited through wire arc additive manufacturing in a bi-metal block. By utilizing optical and electron microscopy techniques, and accompanied by phenomenological and thermodynamic modeling, the work elucidates on the nature of the distinct microstructural features at a new level of detail. Results showcase martensite in the form of a band along the fusion line of the first dissimilar layer, as well as in segregated islands. Within the same bead, yet away from the fusion line, an austenite matrix is identified alongside a large phase fraction of primary ferrite and sparse bainite. These findings enhance our understanding of the nature of the heterogeneous microstructure at the interface of a bi-metal build and establish empirical evidence for future modeling of microstructural development. Supplementary characterization reveals the impact of these microstructural heterogeneities on bulk mechanical performance. Hardness indents exhibit varied results along the interface, peaking at martensite islands with values up to 370HV0.2, surpassing the neighboring matrix by 50%. Under quasi-static tensile loading, bi-metallic specimens display strain partitioning along the fusion boundary, as confirmed by Digital Image Correlation. When compared to the adjoining stainless steel, the diluted interface layer exhibits superior strength (σy: 411 MPa) and comparable ductility (24%), leading to necking and failure away from this region. These results help predict the structural performance of bi-metal parts, and build a base for further research in more intricate loading scenarios, such as crack propagation processes.","Bi-metal interface; Functionally graded material; Microstructural characterization; Wire arc additive manufacturing","en","journal article","","","","","","","","","","","Team Vera Popovich","","",""
"uuid:3d56ecc0-51f7-44c2-82fb-93562942298b","http://resolver.tudelft.nl/uuid:3d56ecc0-51f7-44c2-82fb-93562942298b","Energy-stable discretization of the one-dimensional two-fluid model","Buist, J.F.H. (TU Delft Fluid Mechanics; Centrum Wiskunde & Informatica (CWI)); Sanderse, B. (Centrum Wiskunde & Informatica (CWI)); Dubinkina, S. (Vrije Universiteit Amsterdam); Oosterlee, C. W. (Universiteit Utrecht); Henkes, R.A.W.M. (TU Delft Fluid Mechanics)","","2024","In this paper we present a complete framework for the energy-stable simulation of stratified incompressible flow in channels, using the one-dimensional two-fluid model. Building on earlier energy-conserving work on the basic two-fluid model, our new framework includes diffusion, friction, and surface tension. We show that surface tension can be added in an energy-conserving manner, and that diffusion and friction have a strictly dissipative effect on the energy. We then propose spatial discretizations for these terms such that a semi-discrete model is obtained that has the same conservation properties as the continuous model. Additionally, we propose a new energy-stable advective flux scheme that is energy-conserving in smooth regions of the flow and strictly dissipative where sharp gradients appear. This is obtained by combining, using flux limiters, a previously developed energy-conserving advective flux with a novel first-order upwind scheme that is shown to be strictly dissipative. The complete framework, with diffusion, surface tension, and a bounded energy, is linearly stable to short wavelength perturbations, and exhibits nonlinear damping near shocks. The model yields smoothly converging numerical solutions, even under conditions for which the basic two-fluid model is ill-posed. With our explicit expressions for the dissipation rates, we are able to attribute the nonlinear damping to the different dissipation mechanisms, and compare their effects.","Dissipation; Energy conservation; Energy-stable scheme; Stability; Surface tension; Two-phase pipe flow","en","journal article","","","","","","","","","","","Fluid Mechanics","","",""
"uuid:36bef5f6-0b74-4d92-87af-519a06f42f43","http://resolver.tudelft.nl/uuid:36bef5f6-0b74-4d92-87af-519a06f42f43","Enhancing performance of polar InGaN-based thin film solar cells through intrinsic layer impact optimization: Numerical modeling","El Ghazi, Haddou (Hassan II University of Casablanca); Eker, Yasin Ramazan (Necmettin Erbakan University); En-nadir, Redouane (University of Sidi Mohamed Ben Abdullah); Ahmed, Shrouk Eid Zaki (TU Delft ImPhys/Esmaeil Zadeh group); Basyooni, Mohamed A. (TU Delft Dynamics of Micro and Nano Systems; Selçuk University; National Research Institute of Astronomy and Geophysics)","","2024","The paper deals with the conception and feasibility of the device structure based on the optimized PIN-(In, Ga)N homojunction solar cells. A new and efficient model combining the most realistic ones considering the impacts of band gap narrowing, collection efficiency, Shockley-Read-Hall recombination, and interface polarization is proposed to examine the solar cells' performance numerically. The functioning processes of n-In0.42Ga0.58N/i-(In, Ga)N/p-In0.42Ga0.58N solar cells at room temperature were investigated by calculating their characteristics for the AM1.5D, AM1.5G, and AM0 American Society for Testing and Materials experimental data. Our results show that the indium content, thickness, and defect density of the intrinsic layer strongly influence the characteristics of the InGaN solar cells. As the In-mole fraction increases, Voc, FF and efficiency diminish to reach an independent regime for high In-content. A higher-quality 2μm−In0.43Ga0.57N for 1014cm−3 defect concentration can exhibit as high an efficiency as ≅11.3%, dropping to ≅4.12% for 1016cm−3 one.","(In, Ga)N; Intrinsic layer; Performance; Photovoltaic; PIN; Solar cell","en","journal article","","","","","","","","","","","ImPhys/Esmaeil Zadeh group","","",""
"uuid:b9603c2c-ab8c-4120-8913-df209ca6a628","http://resolver.tudelft.nl/uuid:b9603c2c-ab8c-4120-8913-df209ca6a628","Pre-transplant kidney quality evaluation using photoacoustic imaging during normothermic machine perfusion","Nikolaev, Anton V. (Erasmus MC); Fang, Yitian (Erasmus MC); Essers, Jeroen (Erasmus MC); Panth, Kranthi M. (Erasmus MC); Ambagtsheer, Gisela (Erasmus MC); Clahsen-van Groningen, Marian C. (Erasmus MC); Minnee, Robert C. (Erasmus MC); van Soest, G. (TU Delft Biomechanical Engineering; Erasmus MC; Massachusetts General Hospital); de Bruin, Ron W.F. (Erasmus MC)","","2024","Due to the shortage of kidneys donated for transplantation, surgeons are forced to use the organs with an elevated risk of poor function or even failure. Although the existing methods for pre-transplant quality evaluation have been validated over decades in population cohort studies across the world, new methods are needed as long as delayed graft function or failure in a kidney transplant occurs. In this study, we explored the potential of utilizing photoacoustic (PA) imaging during normothermic machine perfusion (NMP) as a means of evaluating kidney quality. We closely monitored twenty-two porcine kidneys using 3D PA imaging during a two-hour NMP session. Based on biochemical analyses of perfusate and produced urine, the kidneys were categorized into ‘non-functional’ and ‘functional’ groups. Our primary focus was to quantify oxygenation (sO2) within the kidney cortical layer of depths 2 mm, 4 mm, and 6 mm using two-wavelength PA imaging. Next, receiver operating characteristic (ROC) analysis was performed to determine an optimal cortical layer depth and time point for the quantification of sO2 to discriminate between functional and non-functional organs. Finally, for each depth, we assessed the correlation between sO2 and creatinine clearance (CrCl), oxygen consumption (VO2), and renal blood flow (RBF). We found that hypoxia of the renal cortex is associated with poor renal function. In addition, the determination of sO2 within the 2 mm depth of the renal cortex after 30 min of NMP effectively distinguishes between functional and non-functional kidneys. The non-functional kidneys can be detected with the sensitivity and specificity of 80% and 85% respectively, using the cut-off point of sO2 < 39%. Oxygenation significantly correlates with RBF and VO2 in all kidneys. In functional kidneys, sO2 correlated with CrCl, which is not the case for non-functional kidneys. We conclude that the presented technique has a high potential for supporting organ selection for kidney transplantation.","Kidney; Normothermic machine perfusion; Oxygen saturation; Oxygenation; Photoacoustics; Pre-transplant kidney quality; Transplantation","en","journal article","","","","","","","","","","Biomechanical Engineering","","","",""
"uuid:2551cd3b-50f1-4ee4-b48a-2966629e4a51","http://resolver.tudelft.nl/uuid:2551cd3b-50f1-4ee4-b48a-2966629e4a51","Clouds dissipate quickly during solar eclipses as the land surface cools","Trees, V.J.H. (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); de Roode, S.R. (TU Delft Atmospheric Remote Sensing); Wiltink, Job I. (Royal Netherlands Meteorological Institute (KNMI); Wageningen University & Research); Meirink, Jan Fokke (Royal Netherlands Meteorological Institute (KNMI)); Wang, P. (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); Stammes, Piet (Royal Netherlands Meteorological Institute (KNMI)); Siebesma, A.P. (TU Delft Atmospheric Remote Sensing)","","2024","Clouds affected by solar eclipses could influence the reflection of sunlight back into space and might change local precipitation patterns. Satellite cloud retrievals have so far not taken into account the lunar shadow, hindering a reliable spaceborne assessment of the eclipse-induced cloud evolution. Here we use satellite cloud measurements during three solar eclipses between 2005 and 2016 that have been corrected for the partial lunar shadow together with large-eddy simulations to analyze the eclipse-induced cloud evolution. Our corrected data reveal that, over cooling land surfaces, shallow cumulus clouds start to disappear at very small solar obscurations (~15%). Our simulations explain that the cloud response was delayed and was initiated at even smaller solar obscurations. We demonstrate that neglecting the disappearance of clouds during a solar eclipse could lead to a considerable overestimation of the eclipse-related reduction of net incoming solar radiation. These findings should spur cloud model simulations of the direct consequences of sunlight-intercepting geoengineering proposals, for which our results serve as a unique benchmark.","","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:95734e12-75b6-49a9-8ecd-876845ce83f0","http://resolver.tudelft.nl/uuid:95734e12-75b6-49a9-8ecd-876845ce83f0","Strain engineering of nonlinear nanoresonators from hardening to softening","Li, Z. (TU Delft Dynamics of Micro and Nano Systems); Xu, M. (TU Delft QN/Otte Lab; Kavli institute of nanoscience Delft); Norte, R.A. (TU Delft Dynamics of Micro and Nano Systems; Kavli institute of nanoscience Delft); Aragon, A.M. (TU Delft Computational Design and Mechanics); Steeneken, P.G. (TU Delft Dynamics of Micro and Nano Systems; Kavli institute of nanoscience Delft); Alijani, F. (TU Delft Dynamics of Micro and Nano Systems)","","2024","Although strain engineering and soft-clamping techniques for attaining high Q-factors in nanoresonators have received much attention, their impact on nonlinear dynamics is not fully understood. In this study, we show that nonlinearity of high-Q Si3N4 nanomechanical string resonators can be substantially tuned by support design. Through careful engineering of support geometries, we control both stress and mechanical nonlinearities, effectively tuning nonlinear stiffness of two orders of magnitude. Our approach also allows control over the sign of the Duffing constant resulting in nonlinear softening of the mechanical mode that conventionally exhibits hardening behavior. We elucidate the influence of support design on the magnitude and trend of the nonlinearity using both analytical and finite element-based reduced-order models that validate our experimental findings. Our work provides evidence of the role of soft-clamping on the nonlinear dynamic response of nanoresonators, offering an alternative pathway for nullifying or enhancing nonlinearity in a reproducible and passive manner.","","en","journal article","","","","","","","","","","","Dynamics of Micro and Nano Systems","","",""
"uuid:6b3aa4e4-277b-41c5-b300-4e02114dee51","http://resolver.tudelft.nl/uuid:6b3aa4e4-277b-41c5-b300-4e02114dee51","Estimating Mean Profiles and Fluxes in High-Speed Turbulent Boundary Layers Using Inner/Outer-Layer Scalings","Hasan, A.M. (TU Delft Energy Technology); Larsson, Johan (University of Maryland); Pirozzoli, Sergio (Sapienza University of Rome); Pecnik, Rene (TU Delft Energy Technology)","","2024","","","en","journal article","","","","","","","","","","","Energy Technology","","",""
"uuid:bf965b32-ed0b-4e8a-8bca-10cb860a883b","http://resolver.tudelft.nl/uuid:bf965b32-ed0b-4e8a-8bca-10cb860a883b","Modelling Value Change: An Exploratory Approach","de Wildt, T.E. (TU Delft Ethics & Philosophy of Technology); van de Poel, I.R. (TU Delft Ethics & Philosophy of Technology)","","2024","Value and moral change have increasingly become topics of interest in the philosophical literature. Several theoretical accounts have been proposed. These are usually based on certain theoretical and conceptual assumptions. Their strengths and weaknesses are often difficult to determine and compare because they are based on limited empirical evidence. We propose agent-based modeling to build simulation models that can theoretically help us explore accounts of value change. We can investigate whether a simulation model based on a specific account of value change can reproduce relevant phenomena. To illustrate this approach, we build a model based on the pragmatist account of value change proposed by Van De Poel and Kudina (2022). We show that this model can reproduce four relevant phenomena, namely 1) the inevitability and stability of values, 2) societies differ in openness and resistance to change, 3) moral revolutions, and 4) lock-in. This makes this account promising, although more research is needed to see how well it can explain other relevant phenomena and compare its strengths and weaknesses to other accounts. On a more methodological level, our contribution suggests that simulation models might be useful to theoretically explore accounts of value change and make further progress in this area.","Value Change; Moral Change; Agent-Based Modelling; Exploratory Modelling","en","journal article","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:17a96343-c475-4228-840a-7e9f48f64577","http://resolver.tudelft.nl/uuid:17a96343-c475-4228-840a-7e9f48f64577","Editorial: Modelling Values in Social, Technical, and Ecological Systems","Melnyk, A. (TU Delft Ethics & Philosophy of Technology); Edmonds, Bruce (Manchester Metropolitan University); Ghorbani, Amineh (TU Delft System Engineering); van de Poel, I.R. (TU Delft Ethics & Philosophy of Technology)","","2024","This editorial paper for the special section on “Modelling Values in Socio/Technical/Ecological Systems” introduces interdisciplinary perspectives on values and reflects on growing appeals for modelling values. In public and academic discourses, values typically relate to matters of importance (e.g., beliefs, priorities) and principles about what is considered to be good (e.g., moral values) and are often seen as shaping individual and collective behaviour. As shown by eight contributions to this special section, it is relevant for social simulation modelling to dive deeper into embedding values in models in order to explore behavioural change on different levels and across contexts. Our goal with this special section is to stimulate interest in developing various approaches that study and operationalise values in agent-based models to investigate the complex problems raised in social, socio-technical and socio-ecological systems. We conclude with a call for future research to be explicit in their modelling assumptions, thus fostering a vigorous foundation for scientific discourse.","values; value change; simulation modelling","en","journal article","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:ba0940e6-e49a-4bf2-9b94-e5d174ac651f","http://resolver.tudelft.nl/uuid:ba0940e6-e49a-4bf2-9b94-e5d174ac651f","Polyhydroxyalkanoate production in a biofilm by mixed culture phototrophic bacteria","Hülsen, Tim (University of Queensland); Venturato, Daniel (University of Queensland; Urban Utilities, Brisbane); Chan, Clement (University of Queensland); Vandi, Luigi (University of Queensland); Laycock, Bronwyn (University of Queensland); Pratt, Steven (University of Queensland); Stegman, Samuel (University of Queensland); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Batstone, Damien J. (University of Queensland)","","2024","Anoxygenic purple phototrophic bacteria (PPB) were utilised in an 80 L biofilm flat plate photobioreactor to generate polyhydroxyalkanoate (PHA) over 44 cycles, with acetate as feed. Over the cycles, net PHA yield (growth + accumulation) averaged 21% while accumulation yield averaged 55%. Average PHA content was 35 wt% volatile solids (VS), with the majority (>80%) being harvested from the biofilm at 100 gTotal solids (TS) L−1. The PPB microbial population averaged 45% of total population. Detailed cycle studies indicated that PHA content (and yield) peaked at 0.5–1 d into the accumulation stage (peak of 53 wt% VS), suggesting that cycle time optimisation could improve both yield and selection of PHA accumulators. The resulting polymeric material was comprised of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with 95.5 mol% 3-hydroxybutyrate and 4.5 mol% 3-hydroxyvalerate content, but the molecular weight, at >1090 kDa, is unusually high for extracted, microbially produced PHA and a feature of this work.","Biofilm; Polyhydroxyalkanoates; Purple phototrophic bacteria; Resource recovery","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:099c731f-c2e1-41a6-95ae-5bf82639b07c","http://resolver.tudelft.nl/uuid:099c731f-c2e1-41a6-95ae-5bf82639b07c","The use of patient reported outcome measures in oncology clinical practice across Australia and New Zealand","Maharaj, A.D. (TU Delft Policy Analysis; Monash University); Roberts, Natasha (University of Queensland); Jefford, Michael (University of Melbourne); Ng, Jerome (The University of Auckland); Rutherford, Claudia (University of Sydney); Koczwara, Bogda (Flinders University of South Australia)","","2024","Background: While there is increasing evidence on the benefits of PROMs in cancer care, the extent of routine collection and use of PROMs in clinical cancer practice across Australia and New Zealand (ANZ) is unknown. This study examined the prevalence and characteristics of PROMs use in routine clinical cancer care in ANZ. Methods: An online survey was designed and disseminated via professional societies and organisations using a snowball sampling approach to clinical and health administration professionals managing cancer care in ANZ. A poster advertising the study was also circulated on professional social media networks via LinkedIn and Twitter inviting health professionals from ANZ to participate if they were using or intending to use PROMs in clinical cancer practice. Responders opted into the survey via the survey link. Results: From 132 survey views, 91(response rate, 69%) respondents from 56 clinical practices across ANZ agreed to participate in the survey, and of these 55 (n = 55/91, 60%) respondents reported collecting PROMs within their clinical practice. The majority of the respondents were from the State of New South Wales in Australia (n = 21/55, 38%), hospital (n = 35/55, 64%), and a public setting (n = 46/55, 83%). PROMs were collected in all cancer types (n = 21/36, 58%), in all stages of the disease (n = 31/36, 86%), in an adult population (n = 33/36, 92%), applied in English (n = 33/36, 92%), and used to facilitate communication with other reasons (27/36, 75%). A geospatial map analysis provided insights into the variation in PROMs uptake between the two countries and in certain jurisdictions within Australia. This study also highlights the limited resources for PROMs implementation, and a lack of systematic priority driven approach. Conclusion: PROM use across Australia and New Zealand seems variable and occurring predominantly in larger metropolitan centres with limited standardisation of approach and implementation. A greater focus on equitable adoption of PROMs in diverse cancer care settings is urgently needed.","Health policy; Health services research; Oncology; Patient-reported outcome measures; Quality of care","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:163dbbc6-eba7-447c-b1a8-61b9ccaad875","http://resolver.tudelft.nl/uuid:163dbbc6-eba7-447c-b1a8-61b9ccaad875","Composition and thermal properties of Ganymede's surface from JWST/NIRSpec and MIRI observations","Bockelée-Morvan, D. (Observatoire de Paris); Lellouch, E. (Observatoire de Paris); Poch, O. (IPAG); Quirico, E. (IPAG); Cazaux, S.M. (TU Delft Planetary Exploration; Universiteit Leiden); de Pater, I. (TU Delft Astrodynamics & Space Missions; University of California); Fouchet, T. (Observatoire de Paris); Fry, P. M. (University of Wisconsin-Madison); Rodriguez-Ovalle, P. (Observatoire de Paris)","","2024","Context. We present the first spectroscopic observations of Ganymede by the James Webb Space Telescope undertaken in August 2022 as part of the proposal ""ERS observations of the Jovian system as a demonstration of JWST's capabilities for Solar System science"". Aims. We aimed to investigate the composition and thermal properties of the surface, and to study the relationships of ice and non-water-ice materials and their distribution. Methods. NIRSpec IFU (2.9-5.3 μm) and MIRI MRS (4.9-28.5 μm) observations were performed on both the leading and trailing hemispheres of Ganymede, with a spectral resolution of ∼2700 and a spatial sampling of 0.1 to 0.17″ (while the Ganymede size was ∼1.68″). We characterized the spectral signatures and their spatial distribution on the surface. The distribution of brightness temperatures was analyzed with standard thermophysical modeling including surface roughness. Results. Reflectance spectra show signatures of water ice, CO2, and H2O2. An absorption feature at 5.9 μm, with a shoulder at 6.5 μm, is revealed, and is tentatively assigned to sulfuric acid hydrates. The CO2 4.26-μm band shows latitudinal and longitudinal variations in depth, shape, and position over the two hemispheres, unveiling different CO2 physical states. In the ice-rich polar regions, which are the most exposed to Jupiter's plasma irradiation, the CO2 band is redshifted with respect to other terrains. In the boreal region of the leading hemisphere, the CO2 band is dominated by a high wavelength component at ∼4.27 μm, consistent with CO2 trapped in amorphous water ice. At equatorial latitudes (and especially on dark terrains), the observed band is broader and shifted toward the blue, suggesting CO2 adsorbed on non-icy materials, such as minerals or salts. Maps of the H2O Fresnel peak area correlate with Bond albedo maps and follow the distribution of water ice inferred from H2O absorption bands. Amorphous ice is detected in the ice-rich polar regions, and is especially abundant on the northern polar cap of the leading hemisphere. Leading and trailing polar regions exhibit different H2O, CO2, and H2O2 spectral properties. However, in both hemispheres the north polar cap ice appears to be more processed than the south polar cap. A longitudinal modification of the H2O ice molecular structure and/or nanometer- and micrometer-scale texture, of diurnal or geographic origin, is observed in both hemispheres. Ice frost is tentatively observed on the morning limb of the trailing hemisphere, which possibly formed during the night from the recondensation of water subliming from the warmer subsurface. Reflectance spectra of the dark terrains are compatible with the presence of Na- and Mg-sulfate salts, sulfuric acid hydrates, and possibly phyllosilicates mixed with fine-grained opaque minerals, with a highly porous texture. Latitude and local time variations of the brightness temperatures indicate a rough surface with mean slope angles of 15° - 25° and a low thermal inertia Γ = 20-40 J m-2 s-0.5 K-1, consistent with a porous surface, with no obvious difference between the leading and trailing sides.","Infrared: planetary systems; Planets and satellites: composition; Planets and satellites: individual: Ganymede","en","journal article","","","","","","","","","","","Planetary Exploration","","",""
"uuid:875f5379-560c-424d-8015-6c3f1dd8d52f","http://resolver.tudelft.nl/uuid:875f5379-560c-424d-8015-6c3f1dd8d52f","Using multi-stakeholder causal mapping to explore priorities for infrastructure resilience to flooding","Pregnolato, M. (TU Delft Hydraulic Structures and Flood Risk; University of Bristol); West, C. (Mott MacDonald Group Limited); Evans, B. (University of Exeter); Lam, Man Yue (Cardiff University); Chen, A. S. (University of Exeter); Ahmadian, R. (Cardiff University); Djordjević, S. (University of Exeter)","","2024","Urban resilience to natural hazards could make our cities less vulnerable to adverse weather events. However, the implementation of resilience actions is currently not effective, as mechanisms to facilitate collaboration among involved stakeholders are missing. This paper for the first time explores causal mapping as a method to disassemble major issues of urban resilience into a more manageable understanding, and thus identify key objectives, barriers and opportunities in thinking “resilient cities”. In this study, a cognitive-mapping-based workshop was held to elicit information from stakeholders in the remit of urban resilience to flooding. The statements and connections identified during the workshop led a consolidated map, analysed using the StrategyFinder software. This analysis highlighted barriers related to data availability, silo-based approaches and lack of funding; it also evidenced shared goals, such as the need to protect the built environment and minimise impact from flooding. Overall, causal mapping resulted a powerful analytical tool for improving understanding of the complex dynamics of urban resilience, identifying key variables and relationships, as well as eliciting information from stakeholders. Furthermore, this approach facilitated systems thinking, communication and collaboration. This enhanced understanding is fundamental for advancing strategies for future planning, contributing to urban sustainability and liveability.","","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:edaba1eb-4d33-4957-b21e-f3b66e584c90","http://resolver.tudelft.nl/uuid:edaba1eb-4d33-4957-b21e-f3b66e584c90","Substrate-Specific Evolution of Amine Dehydrogenases for Accessing Structurally Diverse Enantiopure (R)-β-Amino Alcohols","Yin, Xinjian (Sun Yat-sen University); Gong, Wenzhong (Sun Yat-sen University); Zeng, Yujing (Sun Yat-sen University); Qiu, Hulin (Sun Yat-sen University); Liu, Lan (Sun Yat-sen University); Hollmann, F. (TU Delft BT/Biocatalysis); Chen, Bishuang (Sun Yat-sen University)","","2024","The biocatalytic oxidative deamination of β-amino alcohols holds significant practical potential in kinetic resolution and/or deracemization process to access (R)-β-amino alcohols. This study exemplifies a notable instance of acquisition and utilization of this valuable oxidative deamination activity. Initially, the mutation N261M (M0) was identified to endow a native valine dehydrogenase with oxidative deamination activity toward a few (S)-β-amino alcohols. Subsequently, a phylogenetic analysis-guided, double-code saturation mutagenesis strategy was proposed to engineer M0's side-chain binding site. This strategy facilitated the substrate-specific evolution of M0, resulting in the creation of a panel of mutants (M1-M4) with noteworthy oxidative deamination activity toward structurally diverse (S)-β-amino alcohols. Using these engineered amine dehydrogenases, termed as β-amino alcohol dehydrogenases (β-AADHs), the complete kinetic resolution and even deracemization of a range of β-amino alcohols have been achieved. This work reports distinct biocatalysts and a synthetic strategy for the synthesis of enantiopure (R)-β-amino alcohols and offers an innovative approach for substrate-specificity engineering of enzymes.","amine dehydrogenases; biocatalysis; enantiopure β-amino alcohols; oxidative deamination; protein engineering","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:e80d9d37-309b-414b-83fb-7f37a8516842","http://resolver.tudelft.nl/uuid:e80d9d37-309b-414b-83fb-7f37a8516842","Influences of Nanostructures of Sn and Ir for the Oxygen Evolution Reaction in Polymer Electrolyte Membrane Water Electrolysis","Bunea, S. (TU Delft ChemE/Catalysis Engineering); Li, M. (TU Delft ChemE/Catalysis Engineering); Demiröz, E. (TU Delft ChemE/Catalysis Engineering); Zeng, Peng (ETH Zürich); Willinger, Marc Georg (ETH Zürich); Urakawa, A. (TU Delft ChemE/Catalysis Engineering)","","2024","The influence of nanostructures and interaction of Sn and Ir in oxygen evolution catalysts in a polymer electrolyte membrane electrolyzer were investigated. For this aim, two synthesis methods, namely, the one-step solution combustion method and the precipitation-deposition method with sodium borohydride reduction, were evaluated to prepare distinct nanostructures. Sn addition to Ir-based oxygen evolution reaction catalysts has been reported to yield materials with higher activity; however, in our case, this was observed only for Sn/Ir catalysts prepared by the precipitation-deposition method. The nanolayer of Sn/SnO2 deposited over metallic Ir particles was identified to enhance the interfacial contacts, resulting in synergistic interactions. By deconvolution of the polarization curves into constituting contributions, the performance improvement was attributed to the higher exchange current density of the Sn/Ir powder as a consequence of a higher number of surface reaction sites created by the Sn-Ir interactions.","","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:6b4ae14c-fdd7-46a3-93c1-a51f4c981738","http://resolver.tudelft.nl/uuid:6b4ae14c-fdd7-46a3-93c1-a51f4c981738","FedViT: Federated continual learning of vision transformer at edge","Zuo, Xiaojiang (Beijing Institute of Technology); Luopan, Yaxin (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Zhang, Qinglong (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2024","Deep Neural Networks (DNNs) have been ubiquitously adopted in internet of things and are becoming an integral part of our daily life. When tackling the evolving learning tasks in real world, such as classifying different types of objects, DNNs face the challenge to continually retrain themselves according to the tasks on different edge devices. Federated continual learning (FCL) is a promising technique that offers partial solutions but yet to overcome the following difficulties: the significant accuracy loss due to the limited on-device processing, the negative knowledge transfer caused by the limited communication of non-IID (non-Independent and Identically Distributed) data, and the limited scalability on the tasks and edge devices. Moreover, existing FCL techniques are designed for convolutional neural networks (CNNs), which have not utilized the full potential of newly emerged powerful vision transformers (ViTs). Considering ViTs depend heavily on training data diversity and volume, we hypothesize ViTs are well-suited for FCL where data arrives continually. In this paper, we propose FedViT, an accurate and scalable federated continual learning framework for ViT models, via a novel concept of signature task knowledge. FedViT is a client-side solution that continuously extracts and integrates the knowledge of signature tasks which are highly influenced by the current task. Each client of FedViT is composed of a knowledge extractor, a gradient restorer and, most importantly, a gradient integrator. Upon training for a new task, the gradient integrator ensures the prevention of catastrophic forgetting and mitigation of negative knowledge transfer by effectively combining signature tasks identified from the past local tasks and other clients’ current tasks through the global model. We implement FedViT in PyTorch and extensively evaluate it against state-of-the-art techniques using popular federated continual learning benchmarks. Extensive evaluation results on heterogeneous edge devices show that FedViT improves model accuracy by 88.61% without increasing model training time, reduces communication cost by 61.55%, and achieves more improvements under difficult scenarios such as large numbers of tasks or clients, and training different complex ViT models.","Catastrophic forgetting; Continual learning; Edge computing; Federated learning; Knowledge transfer negative; Vision transformer","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-22","","","Data-Intensive Systems","","",""
"uuid:9da7e0ad-e8ce-40ed-a915-32ae9749046d","http://resolver.tudelft.nl/uuid:9da7e0ad-e8ce-40ed-a915-32ae9749046d","Multibody dynamic modeling of the behavior of flexible instruments used in cervical cancer brachytherapy","Straathof, R. (TU Delft Medical Instruments & Bio-Inspired Technology; Erasmus MC); Meijaard, J.P. (TU Delft Mechatronic Systems Design); Perez, S.M. (TU Delft Medical Instruments & Bio-Inspired Technology; Erasmus MC); Kolkman-Deurloo, Inger Karine K. (Erasmus MC); Nout, Remi A. (Erasmus MC); Heijmen, Ben J.M. (Erasmus MC); Wauben, L.S.G.L. (TU Delft Medical Instruments & Bio-Inspired Technology); Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology); van de Berg, N.J. (TU Delft Medical Instruments & Bio-Inspired Technology; Erasmus MC)","","2024","Background: The steep radiation dose gradients in cervical cancer brachytherapy (BT) necessitate a thorough understanding of the behavior of afterloader source cables or needles in the curved channels of (patient-tailored) applicators. Purpose: The purpose of this study is to develop and validate computer models to simulate: (1) BT source positions, and (2) insertion forces of needles in curved applicator channels. The methodology presented can be used to improve the knowledge of instrument behavior in current applicators and aid the development of novel (3D-printed) BT applicators. Methods: For the computer models, BT instruments were discretized in finite elements. Simulations were performed in SPACAR by formulating nodal contact force and motion input models and specifying the instruments’ kinematic and dynamic properties. To evaluate the source cable model, simulated source paths in ring applicators were compared with manufacturer-measured source paths. The impact of discrepancies on the dosimetry was estimated for standard plans. To validate needle models, simulated needle insertion forces in curved channels with varying curvature, torsion, and clearance, were compared with force measurements in dedicated 3D-printed templates. Results: Comparison of simulated with manufacturer-measured source positions showed 0.5–1.2 mm median and <2.0 mm maximum differences, in all but one applicator geometry. The resulting maximum relative dose differences at the lateral surface and at 5 mm depth were 5.5% and 4.7%, respectively. Simulated insertion forces for BT needles in curved channels accurately resembled the forces experimentally obtained by including experimental uncertainties in the simulation. Conclusion: The models developed can accurately predict source positions and insertion forces in BT applicators. Insights from these models can aid novel applicator design with improved motion and force transmission of BT instruments, and contribute to the estimation of overall treatment precision. The methodology presented can be extended to study other applicator geometries, flexible instruments, and afterloading systems.","cervical cancer brachytherapy; finite element modeling of source motion; flexible instrument; multibody dynamics","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:c21148a4-4e92-40cf-b9eb-696a657ea4bd","http://resolver.tudelft.nl/uuid:c21148a4-4e92-40cf-b9eb-696a657ea4bd","Should we care about the level of detail in trees when running urban microscale simulations?","Fu, Runnan (Student TU Delft); Pađen, I. (TU Delft Urban Data Science); Garcia Sanchez, C. (TU Delft Urban Data Science)","","2024","Due to lack of information and long geometry generation times, tree geometries are usually oversimplified or even ignored in Computational Fluid Dynamic (CFD) simulations that predict wind and pollutant dispersion in urban areas. Nevertheless, trees are known to impact local wind patterns and air quality levels. Thus, in this paper we explore the effects that tree models automatically reconstructed at diverse Level of Detail (LoD) (1, 2 and 3) have in numerical wind predictions. We address this by comparing the non-dimensional velocity magnitude differences between simulations with multiple tree LoDs. To further understand these differences in changing environmental contexts we use three morphologies: an isolated tree, an idealized street, canyon, and a real urban geometry from Rotterdam, The Netherlands The numerical results show that the velocity magnitude differences between the cases with LoD1 tree models and those with LoD2 tree models can be over 1.0 m/s while the differences between LoD2 and LoD3 cases are rather limited, usually lower than 0.2 m/s. Consequently, through this study we highlight the importance of using tree models in LoD2 or LoD3 at least for CFD simulations of wind flows in urban areas. To further support this conclusion we also analyze the impact of changing wind directions and tree Leaf Area Density (LAD) values in the impact of tree LoDs on wind. The differences found in this work linked to the level of realism in your tree models can support future studies where researchers want to make an informed choice.","CFD; Level of detail; Tree model; Urban area; Wind flow","en","journal article","","","","","","","","","","","Urban Data Science","","",""
"uuid:265ee0f9-203e-42b4-8e44-1c12b4195d45","http://resolver.tudelft.nl/uuid:265ee0f9-203e-42b4-8e44-1c12b4195d45","On the connection between uniqueness from samples and stability in Gabor phase retrieval","Alaifari, Rima (ETH Zürich); Bartolucci, F. (TU Delft Analysis); Steinerberger, Stefan (University of Washington); Wellershoff, Matthias (University of Maryland)","","2024","Gabor phase retrieval is the problem of reconstructing a signal from only the magnitudes of its Gabor transform. Previous findings suggest a possible link between unique solvability of the discrete problem (recovery from measurements on a lattice) and stability of the continuous problem (recovery from measurements on an open subset of R2). In this paper, we close this gap by proving that such a link cannot be made. More precisely, we establish the existence of functions which break uniqueness from samples without affecting stability of the continuous problem. Furthermore, we prove the novel result that counterexamples to unique recovery from samples are dense in L2(R) . Finally, we develop an intuitive argument on the connection between directions of instability in phase retrieval and certain Laplacian eigenfunctions associated to small eigenvalues.","Bargmann transform; Cheeger constant; Counterexamples; Gabor transform; Laplace eigenvalues; Phase retrieval; Poincaré inequality; Sampled Gabor phase retrieval","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:43eefb2e-2a2d-4a0d-8882-5bcd4e44e304","http://resolver.tudelft.nl/uuid:43eefb2e-2a2d-4a0d-8882-5bcd4e44e304","Evaluation and patient experience of wireless noninvasive fetal heart rate monitoring devices","Eenkhoorn, C. (Erasmus MC); Goos, T.G. (TU Delft Medical Instruments & Bio-Inspired Technology; Erasmus MC); Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology); Franx, Arie (Erasmus MC); Eggink, Alex J. (Erasmus MC)","","2024","Introduction: In clinical practice, fetal heart rate monitoring is performed intermittently using Doppler ultrasound, typically for 30 minutes. In case of a non-reassuring heart rate pattern, monitoring is usually prolonged. Noninvasive fetal electrocardiography may be more suitable for prolonged monitoring due to improved patient comfort and signal quality. This study evaluates the performance and patient experience of four noninvasive electrocardiography devices to assess candidate devices for prolonged noninvasive fetal heart rate monitoring. Material and methods: Non-critically sick women with a singleton pregnancy from 24 weeks of gestation were eligible for inclusion. Fetal heart rate monitoring was performed during standard care with a Doppler ultrasound device (Philips Avalon-FM30) alone or with this Doppler ultrasound device simultaneously with one of four noninvasive electrocardiography devices (Nemo Fetal Monitoring System, Philips Avalon-Beltless, Demcon Dipha-16 and Dräger Infinity-M300). Performance was evaluated by: success rate, positive percent agreement, bias, 95% limits of agreement, regression line, root mean square error and visual agreement using FIGO guidelines. Patient experience was captured using a self-made questionnaire. Results: A total of 10 women were included per device. For fetal heart rate, Nemo performed best (success rate: 99.4%, positive percent agreement: 94.2%, root mean square error 5.1 BPM, bias: 0.5 BPM, 95% limits of agreement: −9.7 – 10.7 BPM, regression line: y = −0.1x + 11.1) and the cardiotocography tracings obtained simultaneously by Nemo and Avalon-FM30 received the same FIGO classification. Comparable results were found with the Avalon-Beltless from 36 weeks of gestation, whereas the Dipha-16 and Infinity-M300 performed significantly worse. The Avalon-Beltless, Nemo and Infinity-M300 closely matched the performance of the Avalon-FM30 for maternal heart rate, whereas the performance of the Dipha-16 deviated more. Patient experience scores were higher for the noninvasive electrocardiography devices. Conclusions: Both Nemo and Avalon-Beltless are suitable devices for (prolonged) noninvasive fetal heart rate monitoring, taking their intended use into account. But outside its intended use limit of 36 weeks’ gestation, the Avalon-Beltless performs less well, comparable to the Dipha-16 and Infinity-M300, making them currently unsuitable for (prolonged) noninvasive fetal heart rate monitoring. Noninvasive electrocardiography devices appear to be preferred due to greater comfort and mobility.","Doppler ultrasound; fetal heart rate monitoring; fetal monitoring; noninvasive fetal electrocardiography; prolonged fetal monitoring","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:cf6a9d99-851c-4f5a-992b-cd5dc9cd7dfd","http://resolver.tudelft.nl/uuid:cf6a9d99-851c-4f5a-992b-cd5dc9cd7dfd","Magnetocaloric properties of Mn5(Si,P)B2 compounds for energy harvesting applications","Ojiyed, Hamutu (Student TU Delft); van den Berg, Maarten (Student TU Delft); Batashev, I. (TU Delft RST/Fundamental Aspects of Materials and Energy); Shen, Q. (TU Delft RST/Fundamental Aspects of Materials and Energy); van Dijk, N.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); Brück, E.H. (TU Delft RST/Fundamental Aspects of Materials and Energy)","","2024","The magnetocaloric properties of Mn5Si1-xPxB2 (0 ≤ x ≤ 1) compounds were studied for energy harvesting applications. The crystal structure and the magnetic structure were characterized by powder X-Ray Diffraction and powder Neutron Diffraction. The results indicate that these magnetocaloric materials crystallize in the tetragonal Cr5B3-type crystal structure. The introduction of P causes a stretching of the c axis and compression of the a-b plane, leading to a decrease in the unit-cell volume V. In the ferromagnetic state the magnetic moments align within the a-b plane, and the magnetic moment of the Mn1 atom on the 16 l site is larger than that of the Mn2 atom on the 4c site. The Curie temperature TC can be adjusted continuously from 305 K (x = 1) to 406 K (x = 0) by replacing Si with P. The corresponding magnetic entropy change varies from 1.90 Jkg−1K−1 (x = 0) to 1.35 Jkg−1K−1 (x = 1) for a magnetic field change of 1 T. The PM-FM transition in these compounds corresponds to a second-order phase transition. Mn5Si1-xPxB2 compounds exhibit a magnetization difference of 28.1 - 31.3 Am2kg−1 for a temperature span of 30 K around TC in an applied magnetic field of 1 T. The considerable change in magnetization, the tunable TC near and above room temperature and the absence of thermal hysteresis make these compounds promising candidates for magnetocaloric energy harvesting materials.","Magnetocaloric effect; Magnetocaloric energy harvesting; Magnetocaloric materials; Mn(Si,P)B compounds; Second-order phase transition","en","journal article","","","","","","","","","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:08a5c185-f949-4acc-843b-3e7af457d8a0","http://resolver.tudelft.nl/uuid:08a5c185-f949-4acc-843b-3e7af457d8a0","Uncertainty quantification of the wall thickness and stiffness in an idealized dissected aorta","Gheysen, Lise (Universiteit Gent); Maes, Lauranne (Katholieke Universiteit Leuven); Caenen, Annette (Universiteit Gent; Katholieke Universiteit Leuven); Segers, Patrick (Universiteit Gent); Peirlinck, M. (TU Delft Medical Instruments & Bio-Inspired Technology); Famaey, Nele (Katholieke Universiteit Leuven)","","2024","Personalized treatment informed by computational models has the potential to markedly improve the outcome for patients with a type B aortic dissection. However, existing computational models of dissected walls significantly simplify the characteristic false lumen, tears and/or material behavior. Moreover, the patient-specific wall thickness and stiffness cannot be accurately captured non-invasively in clinical practice, which inevitably leads to assumptions in these wall models. It is important to evaluate the impact of the corresponding uncertainty on the predicted wall deformations and stress, which are both key outcome indicators for treatment optimization. Therefore, a physiology-inspired finite element framework was proposed to model the wall deformation and stress of a type B aortic dissection at diastolic and systolic pressure. Based on this framework, 300 finite element analyses, sampled with a Latin hypercube, were performed to assess the global uncertainty, introduced by 4 uncertain wall thickness and stiffness input parameters, on 4 displacement and stress output parameters. The specific impact of each input parameter was estimated using Gaussian process regression, as surrogate model of the finite element framework, and a δ moment-independent analysis. The global uncertainty analysis indicated minor differences between the uncertainty at diastolic and systolic pressure. For all output parameters, the 4th quartile contained the major fraction of the uncertainty. The parameter-specific uncertainty analysis elucidated that the material stiffness and relative thickness of the dissected membrane were the respective main determinants of the wall deformation and stress. The uncertainty analysis provides insight into the effect of uncertain wall thickness and stiffness parameters on the predicted deformation and stress. Moreover, it emphasizes the need for probabilistic rather than deterministic predictions for clinical decision making in aortic dissections.","Aortic dissection; Finite element analysis; Gaussian process regression; Uncertainty quantification; Vascular mechanics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-03","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:b3fcb62f-10be-403c-81a5-d93fcb2c9394","http://resolver.tudelft.nl/uuid:b3fcb62f-10be-403c-81a5-d93fcb2c9394","A multi-objective optimization and multi-attribute decision-making analysis for technical-thermodynamic-economic evaluation considering the rock damage on production performance of hot dry rock geothermal resources","Xu, Fuqiang (China University of Petroleum - Beijing); Song, Xianzhi (China University of Petroleum - Beijing); Li, Shuang (China University of Petroleum - Beijing); Shi, Yu (Southwest Jiaotong University); Song, G. (TU Delft Applied Geology); Lv, Zehao (Petrochina Research Institute of Petroleum Exploration and Development); Yi, Junlin (China University of Petroleum - Beijing)","","2024","In the long-term mining of geothermal resources in hot dry rock (HDR), the change of thermal stress and pore pressure will increase fracture conductivity evolution, further improving production performance. The optimization and decision-making of the development scheme based on the impact of damage from fractures have yet to be reported. The damage to fractures is essential in designing and adjusting geothermal resource development schemes, particularly in selecting optimal schemes. Therefore, the production performances of HDR resources under different parameters are analyzed to establish a database. Then, minimizing flow resistance, maximizing net power, and maximizing economic benefits are set as optimization goals. Various injection-mining parameters and fracture characteristics are treated as decision variables. Multi-objective optimization and multi-attribute decision analysis is conducted to obtain optimal schemes. Finally, optimal schemes are evaluated and compared, considering damage and non-damage scenarios. Results show that the NSGA-II algorithm is more suitable for optimizing geothermal development questions. Net power and economic benefits of the optimal scheme considering damage increase by 45.84 % and 21.35 % compared to the control scheme with damage. For the non-damage scenario, the above values increased by 31.55 % and 5.15 %, respectively. Compared to not considering the damage, higher mass flow and well spacing of optimal scheme can be selected for the case when damaged. Moreover, the parametric design of the optimal scheme becomes more conservative as the production cycle increases.","Damage; Decision-making; Hot dry rocks; Multiple indicators; Optimization; Production performance","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-06","","","Applied Geology","","",""
"uuid:7e81ae4d-e29e-4082-a812-287c01562824","http://resolver.tudelft.nl/uuid:7e81ae4d-e29e-4082-a812-287c01562824","snRNA-seq analysis in multinucleated myogenic FSHD cells identifies heterogeneous FSHD transcriptome signatures associated with embryonic-like program activation and oxidative stress-induced apoptosis","Zheng, Dongxu (Leiden University Medical Center); Wondergem, Annelot (Leiden University Medical Center); Kloet, Susan (Leiden University Medical Center); Willemsen, Iris (Leiden University Medical Center); Balog, Judit (Leiden University Medical Center); Tapscott, Stephen J. (Fred Hutchinson Cancer Research Center); Mahfouz, A.M.E.T.A. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center); Van Den Heuvel, Anita (Leiden University Medical Center); Van Der Maarel, Silvère M. (Leiden University Medical Center)","","2024","The sporadic nature of DUX4 expression in FSHD muscle challenges comparative transcriptome analyses between FSHD and control samples. A variety of DUX4 and FSHD-associated transcriptional changes have been identified, but bulk RNA-seq strategies prohibit comprehensive analysis of their spatiotemporal relation, interdependence and role in the disease process. In this study, we used single-nucleus RNA-sequencing of nuclei isolated from patient- and control-derived multinucleated primary myotubes to investigate the cellular heterogeneity in FSHD. Taking advantage of the increased resolution in snRNA-sequencing of fully differentiated myotubes, two distinct populations of DUX4-affected nuclei could be defined by their transcriptional profiles. Our data provides insights into the differences between these two populations and suggests heterogeneity in two well-known FSHD-associated transcriptional aberrations: increased oxidative stress and inhibition of myogenic differentiation. Additionally, we provide evidence that DUX4-affected nuclei share transcriptome features with early embryonic cells beyond the well-described cleavage stage, progressing into the 8-cell and blastocyst stages. Altogether, our data suggests that the FSHD transcriptional profile is defined by a mixture of individual and sometimes mutually exclusive DUX4-induced responses and cellular state-dependent downstream effects.","cellular heterogeneity; DUX4; FSHD; muscular dystrophy; single-nucleus RNA-sequencing","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:4fed6676-a637-4bbb-9212-20704504cc2e","http://resolver.tudelft.nl/uuid:4fed6676-a637-4bbb-9212-20704504cc2e","Displayed Monoidal Categories for the Semantics of Linear Logic","Ahrens, B.P. (TU Delft Programming Languages; University of Birmingham); Matthes, Ralph (INPT; Université de Toulouse); van der Weide, N.J. (Radboud Universiteit Nijmegen); Wullaert, K.F. (TU Delft Programming Languages)","Timany, Amin (editor); Traytel, Dmitriy (editor); Pientka, Brigitte (editor); Blazy, Sandrine (editor)","2024","We present a formalization of different categorical structures used to interpret linear logic. Our formalization takes place in UniMath, a library of univalent mathematics based on the Coq proof assistant. All the categorical structures we formalize are based on monoidal categories. As such, one of our contributions is a practical, usable library of formalized results on monoidal categories. Monoidal categories carry a lot of structure, and instances of monoidal categories are often built from complicated mathematical objects. This can cause challenges of scalability, regarding both the vast amount of data to be managed by the user of the library, as well as the time the proof assistant spends on checking code. To enable scalability, and to avoid duplication of computer code in the formalization, we develop ""displayed monoidal categories"". These gadgets allow for the modular construction of complicated monoidal categories by building them in layers; we demonstrate their use in many examples. Specifically, we define linear-non-linear categories and construct instances of them via Lafont categories and linear categories.","categorical semantics; Coq; linear logic; monoidal categories; UniMath","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Programming Languages","","",""
"uuid:6edbc2e4-1cc2-458c-a273-5559bcf009f5","http://resolver.tudelft.nl/uuid:6edbc2e4-1cc2-458c-a273-5559bcf009f5","Univalent Double Categories","van der Weide, N.J. (Radboud Universiteit Nijmegen); Rasekh, Nima (Max Planck Institute for Mathematics); Ahrens, B.P. (TU Delft Programming Languages; University of Birmingham); North, P.R. (Universiteit Utrecht)","Timany, Amin (editor); Traytel, Dmitriy (editor); Pientka, Brigitte (editor); Blazy, Sandrine (editor)","2024","Category theory is a branch of mathematics that provides a formal framework for understanding the relationship between mathematical structures. To this end, a category not only incorporates the data of the desired objects, but also ""morphisms"", which capture how different objects interact with each other. Category theory has found many applications in mathematics and in computer science, for example in functional programming. Double categories are a natural generalization of categories which incorporate the data of two separate classes of morphisms, allowing a more nuanced representation of relationships and interactions between objects. Similar to category theory, double categories have been successfully applied to various situations in mathematics and computer science, in which objects naturally exhibit two types of morphisms. Examples include categories themselves, but also lenses, petri nets, and spans. While categories have already been formalized in a variety of proof assistants, double categories have received far less attention. In this paper we remedy this situation by presenting a formalization of double categories via the proof assistant Coq, relying on the Coq UniMath library. As part of this work we present two equivalent formalizations of the definition of a double category, an unfolded explicit definition and a second definition which exhibits excellent formal properties via 2-sided displayed categories. As an application of the formal approach we establish a notion of univalent double category along with a univalence principle: equivalences of univalent double categories coincide with their identities.","category theory; double categories; formalization of mathematics; univalent foundations","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Programming Languages","","",""
"uuid:4baa11ba-4ad6-45e9-90e3-72999baab954","http://resolver.tudelft.nl/uuid:4baa11ba-4ad6-45e9-90e3-72999baab954","Are civilizations destined to collapse?: Lessons from the Mediterranean Bronze Age","Linkov, Igor (U.S. Army Engineer Research and Development Center); Galaitsi, S. E. (U.S. Army Engineer Research and Development Center); Trump, Benjamin D. (U.S. Army Engineer Research and Development Center); Pinigina, Elizaveta (U.S. Army Engineer Research and Development Center); Rand, Krista (U.S. Army Engineer Research and Development Center); Cline, Eric H. (The George Washington University); Kitsak, M.A. (TU Delft Network Architectures and Services)","","2024","As the world faces multiple crises, lessons from humanity's past can potentially suggest ways to decrease disruptions and increase societal resilience. From 1200 to 1100 BCE, several advanced societies in the Eastern Mediterranean suffered dramatic collapse. Though the causes of the Late Bronze Age Collapse are still debated, contributing factors may include a “perfect storm” of multiple stressors: social and economic upheaval, earthquake clusters, climate change, and others. We examined how collapse might have propagated through the societies’ connections by modeling the Eastern Mediterranean Late Bronze Age trade and socio-political networks. Our model shows that the Late Bronze Age societies made a robust network, where any single node's collapse was insufficient to catalyze the regional collapse that historically transpired. However, modeled scenarios indicate that some paired node disruptions could cause cascading failure within the network. Subsequently, a holistic understanding of the region's network incentive structures and feedback loops can help societies anticipate compounding risk conditions that might lead to widespread collapse and allow them to take appropriate actions to mitigate or adapt societal dependencies. Such network analyses may be able to provide insight as to how we can prevent a collapse of socio-political, economic and trade networks similar to what occurred at the end of the Late Bronze Age. Though such data-intensive analytics were unavailable to these Bronze Age regions, modern society may be able to leverage historical lessons in order to foster improved robustness and resilience to compounding threats. Our work shows that civilization collapses are preventable; we are not necessarily destined to collapse.","Bronze age; Geopolitical conflicts; Networks; Resilience; Risk; Societal collapse","en","journal article","","","","","","","","","","","Network Architectures and Services","","",""
"uuid:eff7b1c1-c51b-4034-b835-a3e17354408e","http://resolver.tudelft.nl/uuid:eff7b1c1-c51b-4034-b835-a3e17354408e","Understanding the role of aliovalent cation substitution on the li-ion diffusion mechanism in Li6+xP1−xSixS5Br argyrodites","Schwietert, T.K. (TU Delft RST/Storage of Electrochemical Energy); Gautam, A. (TU Delft RST/Storage of Electrochemical Energy); Lavrinenko, A.K. (TU Delft RST/Storage of Electrochemical Energy); Drost, David (Student TU Delft); Famprikis, T. (TU Delft RST/Storage of Electrochemical Energy); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy); Vasileiadis, A. (TU Delft RST/Storage of Electrochemical Energy)","","2024","Due to their high ionic conductivity, lithium-ion conducting argyrodites show promise as solid electrolytes for solid-state batteries. Aliovalent substitution is an effective technique to enhance the transport properties of Li6PS5Br, where aliovalent Si substitution triples ionic conductivity. However, the origin of this experimentally observed increase is not fully understood. Our density functional theory (DFT) study reveals that Si4+ substitution increases Li diffusion by activating Li occupancy in the T4 sites. Redistribution of Li-ions within the lattice results in a more uniform distribution of Li around the T4 and neighboring T5 sites, flattening the energy landscape for diffusion. Since the T4 site is positioned in the intercage jump pathway, an increase in the intercage jump rate is found, which is directly related to the macroscopic diffusion and bulk conductivity. Analysis of neutron diffraction experiments confirms partial T4 site occupancy, in agreement with the computational findings. Understanding the aliovalent substitution effect on interstitials is crucial for improving solid electrolyte ionic conductivity and advancing solid-state battery performance.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:d79e9540-06ff-4eb6-a567-fde2b8d7991e","http://resolver.tudelft.nl/uuid:d79e9540-06ff-4eb6-a567-fde2b8d7991e","A novel experimental method to determine substrate uptake kinetics of gaseous substrates applied to the carbon monoxide-fermenting Clostridium autoethanogenum","Allaart, M.T. (TU Delft BT/Environmental Biotechnology); Korkontzelos, Charilaos (Student TU Delft); Sousa, Diana Z. (Wageningen University & Research); Kleerebezem, R. (TU Delft BT/Environmental Biotechnology)","","2024","Syngas fermentation has gained momentum over the last decades. The cost-efficient design of industrial-scale bioprocesses is highly dependent on quantitative microbial growth data. Kinetic and stoichiometric models for syngas-converting microbes exist, but accurate experimental validation of the derived parameters is lacking. Here, we describe a novel experimental approach for measuring substrate uptake kinetics of gas-fermenting microbes using the model microorganism Clostridium autoethanogenum. One-hour disturbances of a steady-state chemostat bioreactor with increased CO partial pressures (up to 1.2 bar) allowed for measurement of biomass-specific CO uptake- and CO2 production rates ((Formula presented.), (Formula presented.)) using off-gas analysis. At a pCO of 1.2 bar, a (Formula presented.) of −119 ± 1 mmol g−1X h−1 was measured. This value is 1.8–3.5-fold higher than previously reported experimental and kinetic modeling results for syngas fermenters. Analysis of the catabolic flux distribution reveals a metabolic shift towards ethanol production at the expense of acetate at pCO (Formula presented.) 0.6 atm, likely to be mediated by acetate availability and cellular redox state. We characterized this metabolic shift as acetogenic overflow metabolism. These results provide key mechanistic understanding of the factors steering the product spectrum of CO fermentation in C. autoethanogenum and emphasize the importance of dedicated experimental validation of kinetic parameters.","acetogen; chemostat; metabolic shift; overflow metabolism; pulse feeding; syngas","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:f6a54572-b462-4df9-8a57-5a4645ad5b3c","http://resolver.tudelft.nl/uuid:f6a54572-b462-4df9-8a57-5a4645ad5b3c","Vanadium-Containing Chloroperoxidase-Catalyzed Versatile Valorization of Phenols and Phenolic Acids","Li, Huanhuan (Xi’an Jiaotong University); Duan, Peigao (Xi’an Jiaotong University); Huang, Yawen (Chinese Academy of Sciences); Cui, Chengsen (Chinese Academy of Sciences); Hollmann, F. (TU Delft BT/Biocatalysis); Ma, Yunjian (South China University of Technology); Wang, Yonghua (South China University of Technology); Zhang, Jie (Chinese Academy of Sciences); Liu, Weidong (Chinese Academy of Sciences); Zhang, Wuyuan (Chinese Academy of Sciences)","","2024","The downstream product transformation of lignin depolymerization is of great interest in the production of high-value aromatic chemicals. However, this transformation is often impeded by chemical oxidation under harsh reaction conditions. In this study, we demonstrate that hypohalites generated in situ by the vanadium-containing chloroperoxidase from Curvularia inaequalis (CiVCPO) can halogenate various electron-rich and electron-poor phenol and phenolic acid substrates. Specifically, CiVCPO enabled decarboxylative halogenation, deformylative halogenation, halogenation, and direct oxidation reactions. The versatile transformation routes for the valorization of phenolic compounds showed up to 99% conversion and 99% selectivity, with a turnover number of 60,700 and a turnover frequency of 60 s-1 for CiVCPO. This study potentially expands the biocatalytic toolbox for lignin valorization.","biocatalysis; decarboxylation; halogenation; lignin valorization; vanadium-containing chloroperoxidase","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-18","","","BT/Biocatalysis","","",""
"uuid:30cc5e36-4388-4cd5-b158-cb8eb0927aba","http://resolver.tudelft.nl/uuid:30cc5e36-4388-4cd5-b158-cb8eb0927aba","Paving the road towards automated homogeneous catalyst design","Kalikadien, A.V. (TU Delft ChemE/Inorganic Systems Engineering); Mirza, Adrian (Student TU Delft); Hossaini, Aydin Najl (Student TU Delft); Sreenithya, Avadakkam (Student TU Delft); Pidko, E.A. (TU Delft ChemE/Inorganic Systems Engineering)","","2024","In the past decade, computational tools have become integral to catalyst design. They continue to offer significant support to experimental organic synthesis and catalysis researchers aiming for optimal reaction outcomes. More recently, data-driven approaches utilizing machine learning have garnered considerable attention for their expansive capabilities. This Perspective provides an overview of diverse initiatives in the realm of computational catalyst design and introduces our automated tools tailored for high-throughput in silico exploration of the chemical space. While valuable insights are gained through methods for high-throughput in silico exploration and analysis of chemical space, their degree of automation and modularity are key. We argue that the integration of data-driven, automated and modular workflows is key to enhancing homogeneous catalyst design on an unprecedented scale, contributing to the advancement of catalysis research.","automation; catalysis; cheminformatics; machine learning; quantum chemistry","en","journal article","","","","","","","","","","","ChemE/Inorganic Systems Engineering","","",""
"uuid:48f00b43-2f12-4a5e-b657-f4f59289eda9","http://resolver.tudelft.nl/uuid:48f00b43-2f12-4a5e-b657-f4f59289eda9","Neural inverse procedural modeling of knitting yarns from images","Trunz, Elena (Universität Bonn); Klein, Jonathan (Universität Bonn; King Abdullah University of Science and Technology); Müller, Jan (Universität Bonn); Bode, Lukas (Universität Bonn); Sarlette, Ralf (Universität Bonn); Weinmann, M. (TU Delft Computer Graphics and Visualisation); Klein, Reinhard (Universität Bonn)","","2024","We investigate the capabilities of neural inverse procedural modeling to infer high-quality procedural yarn models with fiber-level details from single images of depicted yarn samples. While directly inferring all parameters of the underlying yarn model based on a single neural network may seem an intuitive choice, we show that the complexity of yarn structures in terms of twisting and migration characteristics of the involved fibers can be better encountered in terms of ensembles of networks that focus on individual characteristics. We analyze the effect of different loss functions including a parameter loss to penalize the deviation of inferred parameters to ground truth annotations, a reconstruction loss to enforce similar statistics of the image generated for the estimated parameters in comparison to training images as well as an additional regularization term to explicitly penalize deviations between latent codes of synthetic images and the average latent code of real images in the encoder's latent space. We demonstrate that the combination of a carefully designed parametric, procedural yarn model with respective network ensembles as well as loss functions even allows robust parameter inference when solely trained on synthetic data. Since our approach relies on the availability of a yarn database with parameter annotations and we are not aware of such a respectively available dataset, we additionally provide, to the best of our knowledge, the first dataset of yarn images with annotations regarding the respective yarn parameters. For this purpose, we use a novel yarn generator that improves the realism of the produced results over previous approaches.","Inverse procedural modeling; Model fitting; Neural networks; Yarn modeling","en","journal article","","","","","","","","","","","Computer Graphics and Visualisation","","",""
"uuid:7664983e-1c4f-4488-ae8b-38cc4e019108","http://resolver.tudelft.nl/uuid:7664983e-1c4f-4488-ae8b-38cc4e019108","The role of water-treated municipal solid waste incineration (MSWI) bottom ash in microstructure formation and strength development of blended cement pastes","Chen, B. (TU Delft Materials and Environment); Ye, G. (TU Delft Materials and Environment; Universiteit Gent)","","2024","This research explored the microstructure formation and strength development of blended cement pastes prepared with municipal solid waste incineration (MSWI) bottom ash. A new sample preparation approach involving water treatment of MSWI bottom ash was developed to prevent sample cracking caused by the presence of metallic aluminum (Al) in bottom ash. The result showed that ions released during water treatment of MSWI bottom ash delayed cement hydration but promoted ettringite formation in blended cement pastes during the first day. Due to water treatment, the compressive strength of MSWI bottom ash blended cement paste increased to a level similar to that of Class F coal fly blended cement paste after 28 days. Blending water-treated MSWI bottom ash (WMBA) with cement promoted clinker hydration at later stages. The reaction products of WMBA in blended cement system were C-S-H gel and sodicgedrite, which contributed to strength development by filling the capillary pores.","Blended cement; Hydration; Municipal solid waste incineration bottom ash; Supplementary cementitious materials; Water treatment","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:093875bc-da1d-4727-8798-2c3740cb2628","http://resolver.tudelft.nl/uuid:093875bc-da1d-4727-8798-2c3740cb2628","Contactless control of suspended loads for offshore installations: Proof of concept using magnetic interaction","Atzampou, P. (TU Delft Dynamics of Structures); Meijers, P.C. (TU Delft Hydraulic Engineering); Tsouvalas, A. (TU Delft Dynamics of Structures; TU Delft Offshore Engineering); Metrikine, A. (TU Delft Hydraulic Engineering; TU Delft Engineering Structures)","","2024","Current offshore wind turbine installation and positioning methods require mechanical equipment attached on the lifted components and human intervention. The present paper studies the development of a contactless motion compensation technique by investigating a magnetically controlled pendulum. The technique involves the interaction of a magnetic pendulum with an electromagnetic actuator. Two control modes are considered: the imposition of a desired motion to the mass and the motion attenuation of a prescribed pivot excitation. The numerical model is validated and calibrated against experiments and demonstrates excellent predictive capabilities. The control exerted is effective for a broad range of excitation frequencies and amplitudes. Important parameters associated with the performance of the technique such as the separation distance of the magnets and the saturation of the controller are identified. The controllability regions for effective control depending on the characteristics of the excitation are derived. The force amplitude of the contactless actuator is comparable to currently-used active tugger line control systems, but with the additional advantage of both attractive and repulsive forces. The findings of this paper illuminate the path for the further development of a non-contact control technique which has the potential to increase the efficiency of offshore wind installations.","Active vibration control; Contactless control; Magnetic pendulum; Motion manipulation; Offshore wind installation; PID control","en","journal article","","","","","","","","","","Hydraulic Engineering","Dynamics of Structures","","",""
"uuid:b1f93931-ae59-4584-8a5f-25a0a560241f","http://resolver.tudelft.nl/uuid:b1f93931-ae59-4584-8a5f-25a0a560241f","Experimental investigation and thermodynamic assessment of the BaCl2–CeCl3 system","Alders, D.C. (TU Delft RST/Reactor Physics and Nuclear Materials); Vlieland, J. (TU Delft RST/Technici Pool); Thijs, M.A. (TU Delft RID/TS/Technici Pool); Konings, R. (TU Delft RST/Reactor Physics and Nuclear Materials); Smith, A.L. (TU Delft RST/Reactor Physics and Nuclear Materials)","","2024","The thermodynamic and thermo-physical properties of the molten salt system [Formula presented] have been investigated using an experimental and modelling approach. This molten salt system includes a single intermediate compound [Formula presented], whose structure has been investigated using X-ray and neutron diffraction. Furthermore, this system exhibits solubility of [Formula presented] in [Formula presented] at high temperatures up to a concentration of around 25% [Formula presented] at 1060 K. Additionally, our measurements show solubility of [Formula presented] in [Formula presented] up to about 5% [Formula presented] at 973 K. The investigation of these solid solutions has been performed using quenching experiments and subsequent post-characterisation by X-ray diffraction (XRD). Phase diagram equilibria have also been investigated using differential scanning calorimetry (DSC). Using the aforementioned information on phase transitions, intermediate compound formation, and mutual solid solubility, a thermodynamic assessment of the system has been performed using the CALPHAD method. The model for the Gibbs energy of the liquid solution is the quasi-chemical formalism in the quadruplet approximation, while the model for the Gibbs energy of the solid solutions is a two-sublattice polynomial model.","Barium chloride; CALPHAD; Cerium chloride; Chloride salts; Molten salts","en","journal article","","","","","","","","","","","RST/Reactor Physics and Nuclear Materials","","",""
"uuid:5800bca7-69b7-4c26-bde5-414940de6ff3","http://resolver.tudelft.nl/uuid:5800bca7-69b7-4c26-bde5-414940de6ff3","Automatic patient-ventilator asynchrony detection framework using objective asynchrony definitions","van de Kamp, Lars (Eindhoven University of Technology; Demcon Life Sciences and Health); Reinders, Joey (Demcon Life Sciences and Health); Hunnekens, Bram (Demcon Life Sciences and Health); Oomen, T.A.E. (TU Delft Team Jan-Willem van Wingerden; Eindhoven University of Technology); van de Wouw, Nathan (Eindhoven University of Technology)","","2024","Patient-ventilator asynchrony is one of the largest challenges in mechanical ventilation and is associated with prolonged ICU stay and increased mortality. The aim of this paper is to automatically detect and classify the different types of patient-ventilator asynchronies during a patient's breath using the typically available data on commercially available ventilators. This is achieved by a detection and classification framework using an objective definition of asynchrony and a supervised learning approach. The achieved detection performance of the near-real time framework on a clinical dataset is a significant improvement over current clinical practice, therewith and, this framework has the potential to significantly improve the patient comfort and treatment outcomes.","Classification; Detection; Mechanical ventilation; Patient-ventilator asynchrony; Recurrent neural networks; Supervised learning","en","journal article","","","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:4ed7a015-d243-48a5-aada-4087f58f473f","http://resolver.tudelft.nl/uuid:4ed7a015-d243-48a5-aada-4087f58f473f","Impact of oxygen transfer dynamics on the performance of an aerobic granular sludge reactor","Strubbe, Laurence (Universiteit Gent); van Dijk, E.J.H. (TU Delft BT/Environmental Biotechnology; Royal HaskoningDHV); Carrera, Paula (Universiteit Gent); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Volcke, Eveline I.P. (Universiteit Gent)","","2024","The aerobic granular sludge (AGS) process treats wastewater with a significantly lower footprint and energy consumption compared to conventional activated sludge systems. Nevertheless, there is still potential for optimizing its performance, and mathematical models are most valuable tools to this end. Aeration energy consumption deserves particular attention, as it is the largest remaining operating cost for AGS systems. Batch-wisely operated reactors show an increasing oxygen transfer efficiency during aeration, which translates into a dynamic alpha factor. However, the dynamic nature of alpha is neglected in current models. The impact of this simplification on the operating performance was addressed for the first time in this study. Through the development of a novel 1-D biofilm reactor model, calibrated to a full-scale AGS plant, it was shown that the alpha dynamics affect both model structure and calibration, as well as the process performance. The description of the dynamic nature of alpha through the empirical relationship with the soluble biodegradable organic carbon required the addition of the state variable representing soluble slowly biodegradable organic carbon (SCB) to the biokinetic ASM2d model. Simulation results showed that alpha dynamics significantly influences simultaneous nitrification and denitrification and therefore need to be included in mathematical models to optimize AGS process performance. Different process variables such as volume exchange ratio, aeration capacity and granule size can be manipulated to improve reactor design and performance. The practical application of these new insights were discussed regarding the optimization of AGS systems, as well as other batch-wisely operated aerobic wastewater treatment systems.","aerobic granular sludge (AGS); Alpha factor; Modelling and simulation; Oxygen transfer efficiency; Simultaneous nitrification denitrification; Wastewater treatment","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-15","","","BT/Environmental Biotechnology","","",""
"uuid:188f5611-d9ec-44f6-9b08-e847f8e351ae","http://resolver.tudelft.nl/uuid:188f5611-d9ec-44f6-9b08-e847f8e351ae","Economy-wide impacts of socio-politically driven net-zero energy systems in europe","Mayer, Jakob (Karl-Franzens-Universitat Graz); Süsser, Diana (Institute for Advanced Sustainability Studies; Institute for European Energy and Climate Policy); Pickering, Bryn (ETH Zürich); Bachner, Gabriel (Karl-Franzens-Universitat Graz); Sanvito, F.D. (TU Delft Energie and Industrie)","","2024","Net-zero energy system configurations can be met in numerous ways, implying diverse economic effects. However, what is usually ignored in techno-economic and economy-wide analysis are the distinct social-political drivers and barriers, which might constrain certain elements of future energy systems. We thus apply a model ensemble that defines social-political storylines which constrain feasible net-zero configurations of the European energy system. Using these configurations in a macroeconomic general equilibrium model allows us to explore economy-wide effects and ultimately the cost-effectiveness of different systems. We find that social-political storylines provide valuable boundary conditions for feasible net-zero designs of the energy system and that the costliest energy sector configuration in fact leads to the highest European-wide welfare levels. This result originates in indirect effects, particularly positive employment effects, covered by the macroeconomic model. However, adverse public budget effects on the transition to net-zero energy may limit the willingness of policymakers who focus on shorter time-horizons to foster such a development. Our results highlight the relevance of considering the interaction of energy system-changes with labor, emission allowance and capital markets, as well as considering long-term perspectives.","Climate change mitigation; Computable general equilibrium; Cost-effectiveness; Energy system design; Social-political storylines","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:d2c306d4-fdf4-49c5-ac54-b09b7d3796c9","http://resolver.tudelft.nl/uuid:d2c306d4-fdf4-49c5-ac54-b09b7d3796c9","Transfer learning-based methodologies for Dynamic Thermal Rating of transmission lines","Paldino, Gian Marco (Vrije Universiteit Brussel); De Caro, Fabrizio (Vrije Universiteit Brussel; Università degli Studi del Sannio); De Stefani, J. (TU Delft Information and Communication Technology; Vrije Universiteit Brussel); Vaccaro, Alfredo (Università degli Studi del Sannio); Bontempi, Gianluca (Vrije Universiteit Brussel)","","2024","Dynamic Thermal Rating (DTR) enhances grid flexibility by adapting line capabilities to weather conditions. For this purpose, DTR-based technologies require reliable and continuous measurement of the conductor temperature along the line route, which could hinder their wide-scale deployment due to the prohibitively high number of required sensors. Existing machine learning-based DTR methods infer conductor temperature from weather variables avoiding using complex and expensive measurement techniques, but their estimation accuracy greatly relies on the availability of a comprehensive set of measured data. To face these issues, this paper proposes the usage of transfer learning, a data-driven technique allowing the reduction of the number of sensors by transferring knowledge from a single calibrated source sensor to many target sensors. To the best of the author's knowledge, at the time of writing, the proposed approach is the first application of Transfer Learning in the domain of DTR which is validated on real transmission lines data. Experimental results from several real transmission lines equipped with self-organizing sensors-based DTR architecture show that transfer learning enhances the conductor temperature estimation reliability and accuracy of machine learning-based DTR techniques, suggesting the potential for practical applications, and reducing costs without losing accuracy for practitioners and system operators.","Dynamic Thermal Rating; Power system operation and control; Temperature estimation; Transfer learning","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-03","","","Information and Communication Technology","","",""
"uuid:e56707db-7f4f-4000-826d-81d3da05caa9","http://resolver.tudelft.nl/uuid:e56707db-7f4f-4000-826d-81d3da05caa9","School participation of autistic youths: The influence of youth, family and school factors","Li, B. (TU Delft Design Conceptualization and Communication; Universiteit Leiden); Heyne, David (Deakin University); Scheeren, Anke (Vrije Universiteit Amsterdam); Blijd-Hoogewys, Els (INTER-PSY; Rijksuniversiteit Groningen); Rieffe, Carolien (Universiteit Leiden; University of Twente; University College London (UCL))","","2024","Many autistic youths experience restricted school participation. The present study investigated the influences of youth, family and school factors on autistic youths’ school participation. Parents of 200 Dutch autistic youths (age range: 4–16 years, Mage = 12.23 years, SDage = 2.93 years) filled in questionnaires in a national survey for autistic individuals, reporting the school participation, age and autistic traits of their child, parents’ education level and self-efficacy for supporting their child’s schoolwork, and the impact of problems their child experienced with the physical and social environments of the school. Multivariate linear regression analysis using imputed data revealed that among the six predictor variables, only the impact of problems autistic youths experienced with the physical environment of school was negatively associated with their school participation. This study provided support for the essential role of the school environment in predicting autistic youths’ school participation, indicating that problematic aspects in the school environment could have a greater impact on autistic youths’ school participation than youth factors or family factors. This highlights the need to create a more accommodating environment at school, where autistic youths can participate easily and comfortably. Lay abstract: School-aged youths have a basic human right to participate in educational and recreational activities at school. Yet, autistic youths are at high risk of being excluded from school and from school-based activities. It is important to understand how this occurs, to ensure that all autistic youths have opportunities to participate in school activities that are equal to the opportunities of their non-autistic peers. The present study investigated multiple influences on the school participation of autistic youths, including youth factors (age and autistic traits), family factors (parent education level and parental self-efficacy for supporting their child’s schoolwork) and school factors (the impact of problems autistic youths experienced with the physical and social environments of school). Using an online survey, we gathered the views and experiences of the parents of 200 autistic youths aged between 4 and 16 years, in the Netherlands. We found that among the factors, only the impact of problems that autistic youths experienced with the physical environment of school was associated with their school participation. In particular, autistic youths who experienced greater difficulties with the physical environment of school had lower levels of school participation. Our findings highlight the pressing need to modify school environments to better accommodate the needs of autistic youths so that they can participate easily and comfortably.","autistic traits; autistic youth; physical environment; school participation; social environment","en","journal article","","","","","","","","","","","Design Conceptualization and Communication","","",""
"uuid:f91f1149-38fd-4088-88e1-1ac28ac8c417","http://resolver.tudelft.nl/uuid:f91f1149-38fd-4088-88e1-1ac28ac8c417","Biomarkers to discriminate between aseptic loosened and stable total hip or knee arthroplasties: a systematic review","Hasan, Shaho (Leiden University Medical Center); van Schie, Peter (Leiden University Medical Center); Kaptein, B.L. (Leiden University Medical Center); Schoones, Jan W. (Leiden University Medical Center); Marang-van de Mheen, P.J. (TU Delft Safety and Security Science; Leiden University Medical Center); Nelissen, R.G.H.H. (Leiden University Medical Center)","","2024","b>Background: Loosening is a major cause for failure of total hip and total knee arthroplasties (THAs/TKAs). Preemptive diagnostics of asymptomatic loosening could open strategies to prevent gross loosening. A multitude of biomarkers may discriminate between loosened and stable implants, but it is unknown which have the best performance. The present systematic review aimed to assess which biomarkers have shown the most promising results in discriminating between stable and aseptic loosened THAs and TKAs.
Methods: PubMed, Embase, Web of Science, Cochrane Library, and Academic Search Premier were systematically searched up to January 2020 for studies including THA/TKA and biomarkers to assess loosening. Two reviewers independently screened records, extracted data, and assessed the risk of bias using the ICROMS tool to classify the quality of the studies.
Results: Twenty-eight (three high-quality) studies were included, reporting on a median of 48 patients (interquartile range 28–69). Serum and urine markers were evaluated in 22 and 10 studies, respectively. Tumor necrosis factor α and osteocalcin were significantly higher in loosened compared with stable implants. Urinary N-terminal telopeptide had significantly elevated levels in loosened prostheses.
Conclusion: Several serum and urine markers were promising in discriminating between loosened and stable implants. We recommend future studies to evaluate these biomarkers in a longitudinal fashion to assess whether progression of loosening is associated with a change in these biomarkers. In particular, high-quality studies assessing the usability of these biomarkers are needed.","arthroplasty; biomarkers; loosening","en","review","","","","","","","","","","","Safety and Security Science","","",""
"uuid:828b2425-e579-4ebd-b83a-b283f2d2342a","http://resolver.tudelft.nl/uuid:828b2425-e579-4ebd-b83a-b283f2d2342a","Wind-solar technological, spatial and temporal complementarities in Europe: A portfolio approach","López Prol, Javier (Yonsei University); de Llano Paz, Fernando (Universidade da Coruña); Calvo-Silvosa, Anxo (Universidade da Coruña); Pfenninger, Stefan (TU Delft Energie and Industrie); Staffell, Iain (Imperial College London)","","2024","Climate change and geopolitical risks call for the rapid transformation of electricity systems worldwide, with Europe at the forefront. Wind and solar are the lowest cost, lowest risk, and cleanest energy sources, but their variability poses integration challenges. Combining both technologies and integrating regions with dissimilar generation patterns optimizes the trade-off between maximizing energy output and minimizing its variability, which respectively give the lowest levelized cost and lowest integration cost. We apply the Markowitz mean-variance framework to a rich multi-decade dataset of wind and solar productivity to quantify the potential benefits of spatially integration of renewables across European countries at hourly, daily and monthly timescales. We find that optimal cross-country coordination of wind and solar capacities across Europe's integrated electricity system increases capacity factor by 22% while reducing hourly variability by 26%. We show limited benefits to solar integration due to consistent output profiles across Europe. Greater wind integration yields larger benefits due to the diversity of regional weather patterns. This framework shows the importance of considering renewable projects not in isolation, but as interconnected parts of a pan-continental system. Our results can guide policymakers towards strategic energy plans that reduce system-wide costs of renewable electricity, accelerating the clean energy transition.","Decarbonization; Energy transition; Integration costs; Integration of electricity markets; Inttermitency; LCOE; Solar; Variability; Variable renewable energy; Wind","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:f1e04a82-8256-4a32-8f73-2a2033bf6661","http://resolver.tudelft.nl/uuid:f1e04a82-8256-4a32-8f73-2a2033bf6661","Contested port cities: Logistical frictions and civic mobilization in Genoa and Venice","Savoldi, F. (TU Delft History, Form & Aesthetics)","","2024","This article examines the increasingly conflictual relationship between ports and their surrounding communities at a time of wide-reaching infrastructural expansion. It highlights how the centralization of power and logistical gigantism produce deterritorializing frictions, decoupling inhabitants from their territories and creating the conditions for social contestation. It calls for a rethinking of the role of communities in contemporary port-city governance, with an emphasis on imaginaries of re-territorialization produced through social mobilization. I frame the increasing contestation in port cities through a critical approach to logistics, arguing that citizen engagement holds the potential to drastically readdress the port-city relationship. It examines the cases of Genoa and Venice using ethnographic methods and reconstructs a historically in-depth counter-narrative of interactions between port, city and citizen. I contextualize specific frictions between port and city through the rise in social mobilizations. The article shows how social mobilization challenges the status quo in different ways, producing changes and illuminating pathways toward more sustainable forms of coexistence between ports and cities.","contestation; counter-logistics; frictions; port cities; social mobilisation","en","journal article","","","","","","","","","","","History, Form & Aesthetics","","",""
"uuid:2b447c46-3922-4fd3-9ead-d960025e3fce","http://resolver.tudelft.nl/uuid:2b447c46-3922-4fd3-9ead-d960025e3fce","Experimental study on workability and permeability of sandy soils conditioned with thickened foam","Feng, Zhiyao (Central South University China); Wang, Shuying (Central South University China); Qu, Tongming (The Hong Kong University of Science and Technology); Zheng, X. (TU Delft Geo-engineering; Central South University China); Ling, Fanlin (Central South University China)","","2024","Water spewing and muck plugging often occur during earth pressure balance (EPB) shield machines tunnelling in water-rich sandy strata, even though the conventional foam has been employed to condition sandy soils. In this study, a novel thickened foaming agent suitable for EPB shield tunnelling in water-rich sandy strata is developed. In contrast to conventional foam-conditioned sands, the thickened foam-conditioned sand has a low permeability due to the consistent filling of soil pores with the thickened foam, and the initial permeability coefficient decreases by approximately two orders of magnitude. It also exhibits a suitable workability, which is attributed to the enhanced capability of the thickened foam to condition sandy soils. In addition, the effect of concentration on the stability of the foam is explained by the Gibbs-Marangoni effect, and conditioning mechanisms for the thickened foam on sands are discussed from the evolution of foam bubbles.","Earth pressure balance (EPB) shield; Foam-conditioned sand; Permeability; Thickened foam; Workability","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:d9e88bd8-9212-4f52-a622-c1067662484c","http://resolver.tudelft.nl/uuid:d9e88bd8-9212-4f52-a622-c1067662484c","Studying the Pedestrian Level-of-Service (PLoS): Lessons regarding the combination of survey and monitoring data","Duives, D.C. (TU Delft Transport and Planning); Ton, Danique (NS Stations)","","2024","Crowding is often analyzed using crowd dynamics variables. Yet, it is questionable whether quantitative variables fully describe the perception of crowdedness. This paper presents four case studies into the Pedestrian Level-of-Service (PLoS), featuring a 1) mass event, 2) shopping environment, 3) festival, and 4) touristic hotspot. The relation between the PLoS and the crowds' movement dynamics is studied using a combination of survey and monitoring data. This study establishes that the perception of LoS is partly related to the crowds' dynamics, and that the combination of in-situ surveys and monitoring data provides more comprehensive insights w.r.t. pedestrians' perceptions of space.","Crowd dynamics; Crowd management; Crowd monitoring; Pedestrian Level-of-Service; Safety; Survey","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:4edf0169-a558-4a8b-815a-88781b85c314","http://resolver.tudelft.nl/uuid:4edf0169-a558-4a8b-815a-88781b85c314","Cretaceous climate change evidenced in the Senegalese rock record, NW Africa","Pearson, M. (The University of Manchester; British Geological Survey); Casson, M. (The University of Manchester; Equinor ASA); Millar, I. (Kingsley Dunham Centr, Nottingham); Charton, R.J.G. (TU Delft Applied Geology; The University of Manchester); Redfern, J. (The University of Manchester)","","2024","Climate change directly impacts the source, mode and volume of sediment generation which can be observed in the rock record. To accurately model source to sink systems, in addition to hinterland geology, tectonics and transport distance, a thorough comprehension of the climate is essential. In this study we evaluate the role of climate on Cretaceous sediment delivery into the Senegal Basin, NW Africa, using data recorded from extensive sampling of basinal sediments. This is achieved through the mineralogical characterisation by X-ray diffraction and 146Nd/144Nd and 86Sr/88Sr isotopic analyses, which are correlated against existing, climate, tectonic and oceanographic models. Examples of climatic indicators include the change from predominantly smectitic deep marine basinal-clays recorded from the Cretaceous in DSDP wells 367 and 368 to clays with increased illite and kaolinite content, observed during the Albian and Cenomanian-Turonian, interpreted to be representative of higher humidity following the kaolinisation of hinterland source-rocks. Another climate indicator is the observation of palygorskite in deep-marine sediments, noted to be indicative of ocean anoxia related to the authigenesis of marine-smectite, a product of warm saline bottom waters and increased abundancy of silicon. The increase in salinity is interpreted to be a biproduct of elevated temperatures throughout the Cenomanian and increased denudation of the North Atlantic circumjacent continental evaporite-belts. Increase in silicon (biogenic) is related to a result of ocean-wide mass extinction of foraminifera during OAE2 triggered by the eruption of the Caribbean large igneous province. The results suggest that Cretaceous climate evolution of Senegal can be divided into four stages: 1. Berriasian-Barremian; an arid-period with monsoonal weather producing modest fluvial systems restricted to coastal regions. 2. Aptian-Albian; the establishment of a paleo-Intertropical Convergence Zone began to increase global temperature and humidity as recognised by the increase in kaolinite content. 3. Cenomanian-Turonian; the Cretaceous Thermal Maximum hothouse period incurring exceptional temperatures and humidity. This is represented as an antithetical shift in clay mineralogy from chlorite-illite to smectite-kaolinite throughout most of the onshore and nearshore basinal sediments. 4. Coniacian-Maastrichtian; transitional from tropical-to-tropical swamp-like conditions evidenced by increased onshore basin sediment capture and a shift in vegetation to aquatic-fern species. The impact of climate change throughout the Cretaceous produced dynamic shifts in both river size and source-catchment, witnessing exception rates of denudation during the hotter and more humid periods, which climaxed during the Cenomanian and Turonian as a result of the Cretaceous Thermal Maximum. This eroded sediment was deposited in both the onshore and offshore basins during the mid-late Cretaceous but became increasingly restricted to the onshore segment of the basin during the Late Cretaceous.","Clay-minerals; Climate; Cretaceous; NW-Africa; Ocean-anoxia; Senegal","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-25","","","Applied Geology","","",""
"uuid:1748f6c4-08e2-4124-aee3-68398205bfaf","http://resolver.tudelft.nl/uuid:1748f6c4-08e2-4124-aee3-68398205bfaf","Tunable visible emission and persistent luminescence of BaGa2O4:Cu2+","Wang, Lei (Hefei University of Technology); Zhao, Ning (Hefei University of Technology); Zhu, Changrui (Hefei University of Technology); Chen, Lei (Hefei University of Technology); Jiang, Yang (Hefei University of Technology); Zhou, Rulong (Hefei University of Technology); Liu, Yanfang (Hefei University of Technology); Qu, Bingyan (Hefei University of Technology); Hintzen, H.T.J.M. (TU Delft RST/Luminescence Materials)","","2024","In the field of solid-state luminescence, Cu2+ has long been widely acknowledged for its capacity to emit infrared light. However, the occurrence of visible emission from Cu2+ ions had been infrequently observed and reported. In this study, we made an intriguing discovery by examining the behavior of Cu2+ within an irregular coordination environment of Ba in BaGa2O4. When excited by UV light, Cu2+ unexpectedly gave a vibrant yellow–red emission, covering a wavelength range spanning from 500 to 750 nm. More noteworthy, by simply manipulating the excitation wavelength or adjusting the temperature, the peak wavelength of the emission could be effectively tuned from approximately 600 to 660 nm, which could be attributed to the luminescence nature of the charge transfer (CT) between O2− and Cu2+. Moreover, the phosphor material displayed a remarkable persistent luminescence (PerL) lasting up to 12 h after UV light excitation. Through thermoluminescence (TL) measurements and first-principle calculations, we found that the intrinsic defects, such as vacancies of oxygen and gallium (VO and VGa″), played important roles for the PerL phenomena. These findings highlighted the exceptional tunability and PerL properties of BaGa2O4:Cu2+. Our study provided a new potential guideline for the design of Cu2+-activated phosphors in visible region, and opened up new avenues for the research in related functional luminescence materials.","Cu luminescence; Mechanism; Persistent luminescence; Phosphors; Tunable emission","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-01","","","RST/Luminescence Materials","","",""
"uuid:a311fa47-f645-4c2e-b5b4-0c80c4518777","http://resolver.tudelft.nl/uuid:a311fa47-f645-4c2e-b5b4-0c80c4518777","Influence of geometrical imperfections and residual stresses on the reliability of high strength steel welded I-section columns using Monte Carlo simulation","Ferreira Filho, José Osvaldo (Universidade de Coimbra); da Silva, Luís Simões (Universidade de Coimbra); Tankova, T. (TU Delft Steel & Composite Structures); Carvalho, Hermes (Universidade Federal de Minas Gerais; Universidade de São Paulo)","","2024","This paper aims to assess the influence of geometrical imperfections and residual stresses on the reliability of the stability design rules for steel columns in Eurocode 3 considering a full probabilistic approach and further validate the new buckling curves in the scope of the ongoing revision of the Structural Eurocodes. A reliability assessment of major- and minor-axis flexural buckling of high-strength steel (HSS) welded I-section columns was performed, considering all basic variables as random, including the geometrical and material imperfections, in addition to the material properties of steel and the geometry of the cross-section. An advanced finite element model calibrated with experimental test results is used to perform a very large (290,126 simulations) parametric study covering the majority of practical geometries. Subsequently, Monte Carlo simulation is used to estimate the design values of the buckling resistance that correspond to the target probability of failure of the Eurocodes. Finally, these values are compared to the proposed buckling curves for HSS columns, showing good agreement and supporting their adoption in the revised EN 1993–1-1. It is also concluded that it is on the safe side to carry out a reliability assessment with deterministic reference values for structural imperfections.","Buckling resistance of columns; Eurocode 3; High strength steel; Monte Carlo simulation; Reliability analysis","en","journal article","","","","","","","","","","","Steel & Composite Structures","","",""
"uuid:04060e07-4148-49e2-999d-d18c3e9610fa","http://resolver.tudelft.nl/uuid:04060e07-4148-49e2-999d-d18c3e9610fa","Mechanical properties of 3D printed CMT-WAAM 316 LSi stainless steel walls","Andrade, D. G. (Universidade de Coimbra); Tankova, T. (TU Delft Steel & Composite Structures; Universidade de Coimbra); Zhu, C. (Universidade de Coimbra); Branco, R. (Universidade de Coimbra); da Silva, L. Simões (Universidade de Coimbra); Rodrigues, D. M. (Universidade de Coimbra)","","2024","The use of 3D printed stainless steel requires a deep knowledge of its mechanical properties. This paper presents material characterisation of 316LSi austenitic stainless-steel coupons manufactured by CMT-WAAM, considering different deposition directions. The specimens were tested according to ISO 6892-1, the fractures surfaces were examined by SEM for machined and as-built conditions. The material was subject to hardness test and deep microstructural analyses, to assess the anisotropy in material properties at the micro and macro scales, respectively. A thermal analysis performed by infrared thermography of the material deposition in CMT-WAAM was also performed to establish the influence of the temperature evolution (versus time and position) on the microstructural and mechanical properties of the deposited walls. Finally, a statistical assessment was carried out, including results available in the literature and a material model available in the literature was adjusted to the test results, enabling to conclude that it is possible of accurately reproducing the uniaxial stress-strain behaviour, therefore providing a necessary input for the design of steel structures with 3D printed stainless steel.","Directed energy deposition; Mechanical properties; Stainless steel; Thermal analysis; Wire arc additive manufacturing","en","journal article","","","","","","","","","","","Steel & Composite Structures","","",""
"uuid:679fb87d-5bb6-4455-b5e9-676da83e7420","http://resolver.tudelft.nl/uuid:679fb87d-5bb6-4455-b5e9-676da83e7420","An Ultrasound Matrix Transducer for High-Frame-Rate 3-D Intra-cardiac Echocardiography","Simoes dos Santos, D. (TU Delft ImPhys/Verweij group; TU Delft ImPhys/Medical Imaging); Ossenkoppele, B.W. (TU Delft ImPhys/Medical Imaging); Hopf, Y.M. (TU Delft Electronic Instrumentation); Soozande, Mehdi (Erasmus MC); Noothout, E.C. (TU Delft ImPhys/Verweij group); Vos, H.J. (TU Delft ImPhys/Verweij group; Erasmus MC); Bosch, Johan G. (Erasmus MC); Pertijs, M.A.P. (TU Delft Electronic Instrumentation); Verweij, M.D. (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Verweij group; Erasmus MC); de Jong, N. (TU Delft ImPhys/De Jong group; Erasmus MC)","","2024","Objective: Described here is the development of an ultrasound matrix transducer prototype for high-frame-rate 3-D intra-cardiac echocardiography. Methods: The matrix array consists of 16 × 18 lead zirconate titanate elements with a pitch of 160 µm × 160 µm built on top of an application-specific integrated circuit that generates transmission signals and digitizes the received signals. To reduce the number of cables in the catheter to a feasible number, we implement subarray beamforming and digitization in receive and use a combination of time-division multiplexing and pulse amplitude modulation data transmission, achieving an 18-fold reduction. The proposed imaging scheme employs seven fan-shaped diverging transmit beams operating at a pulse repetition frequency of 7.7 kHz to obtain a high frame rate. The performance of the prototype is characterized, and its functionality is fully verified. Results: The transducer exhibits a transmit efficiency of 28 Pa/V at 5 cm per element and a bandwidth of 60% in transmission. In receive, a dynamic range of 80 dB is measured with a minimum detectable pressure of 10 Pa per element. The element yield of the prototype is 98%, indicating the efficacy of the manufacturing process. The transducer is capable of imaging at a frame rate of up to 1000 volumes/s and is intended to cover a volume of 70° × 70° × 10 cm. Conclusion: These advanced imaging capabilities have the potential to support complex interventional procedures and enable full-volumetric flow, tissue, and electromechanical wave tracking in the heart.","Application-specific integrated circuit; High frame rate; Intra-cardiac echocardiography; Matrix array; Three-dimensional; Ultrasound transducer","en","journal article","","","","","","","","","","","ImPhys/Verweij group","","",""
"uuid:2d5c0e74-b276-4819-972a-36fe9d1539a8","http://resolver.tudelft.nl/uuid:2d5c0e74-b276-4819-972a-36fe9d1539a8","Railway sleeper vibration measurement by train-borne laser Doppler vibrometer and its speed-dependent characteristics","Zeng, Y. (TU Delft Reservoir Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","","2024","A train-borne laser Doppler vibrometer (LDV) directly measures the dynamic response of railway track components from a moving train, which has the potential to complement existing train-borne technologies for railway track monitoring. This paper proposes a holistic methodology to characterize train-borne LDV measurements by combining computer-aided approaches and real-life measurements. The focus is on the speed-dependent characteristics because the train speed affects the intensity of railway sleeper vibrations and the intensity of speckle noise, which further affects the quality and usability of the measured signals. First, numerical models are established and validated to simulate sleeper vibrations and speckle noise separately. Then, a vibration–noise separation method is proposed to effectively extract speckle noise and structural vibrations from LDV signals measured at different speeds. The parameters of the separation method are tuned using simulation signals. The method is then validated using laboratory measurements in a vehicle-track test rig and applied to field measurements on a railway track in Rotterdam, the Netherlands. Further, the speed-dependent characteristics of train-borne LDV measurement are determined by analyzing the competition between sleeper vibrations and speckle noise at different speeds. Simulation and measurement results show that an optimal speed range yields the highest signal-to-noise ratio, which varies for different track structures, measurement configurations, and operational conditions. The findings demonstrate the potential of train-borne LDV for large-scale rail infrastructure monitoring.","","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:34f73c81-fc73-4583-afc7-55ab99d38ada","http://resolver.tudelft.nl/uuid:34f73c81-fc73-4583-afc7-55ab99d38ada","Automatic Max-Likelihood Envelope Detection Algorithm for Quantitative High-Frame-Rate Ultrasound for Neonatal Brain Monitoring","Kortenbout, A.J. (Erasmus MC); Costerus, Sophie (Erasmus MC); Dudink, Jeroen (University Medical Center Utrecht); de Jong, N. (TU Delft ImPhys/Verweij group; Erasmus MC); de Graaff, Jurgen C. (Erasmus MC; Weill Cornell Medical College); Vos, H.J. (TU Delft ImPhys/Verweij group; Erasmus MC); Bosch, Johan G. (Erasmus MC)","","2024","Objective: Post-operative brain injury in neonates may result from disturbed cerebral perfusion, but accurate peri-operative monitoring is lacking. High-frame-rate (HFR) cerebral ultrasound could visualize and quantify flow in all detectable vessels using spectral Doppler; however, automated quantification in small vessels is challenging because of low signal amplitude. We have developed an automatic envelope detection algorithm for HFR pulsed wave spectral Doppler signals, enabling neonatal brain quantitative parameter maps during and after surgery. Methods: HFR ultrasound data from high-risk neonatal surgeries were recorded with a custom HFR mode (frame rate = 1000 Hz) on a Zonare ZS3 system. A pulsed wave Doppler spectrogram was calculated for each pixel containing blood flow in the image, and spectral peak velocity was tracked using a max-likelihood estimation algorithm of signal and noise regions in the spectrogram, where the most likely cross-over point marks the blood flow velocity. The resulting peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistivity index (RI) were compared with other detection schemes, manual tracking and RIs from regular pulsed wave Doppler measurements in 10 neonates. Results: Envelope detection was successful in both high- and low-quality arterial and venous flow spectrograms. Our technique had the lowest root mean square error for EDV, PSV and RI (0.46 cm/s, 0.53 cm/s and 0.15, respectively) when compared with manual tracking. There was good agreement between the clinical pulsed wave Doppler RI and HFR measurement with a mean difference of 0.07. Conclusion: The max-likelihood algorithm is a promising approach to accurate, automated cerebral blood flow monitoring with HFR imaging in neonates.","Cerebral ultrasound; Envelope detection; High-frame-rate ultrasound; High-risk surgery; Max-likelihood; Monitoring; Neonates; Pulsed wave Doppler; Spectral Doppler","en","journal article","","","","","","","","","","","ImPhys/Verweij group","","",""
"uuid:d37c5259-3862-4faa-a177-f602c009d8fe","http://resolver.tudelft.nl/uuid:d37c5259-3862-4faa-a177-f602c009d8fe","Acoustic streaming-based calibration of ultrasound transducers","Simoes dos Santos, D. (TU Delft ImPhys/Verweij group; TU Delft ImPhys/Medical Imaging); Baldini, L.B. (TU Delft ImPhys/Verweij group); Vos, H.J. (TU Delft ImPhys/Verweij group; Erasmus MC); Verweij, M.D. (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Verweij group; Erasmus MC); de Jong, N. (TU Delft ImPhys/De Jong group; Erasmus MC); van Neer, P.L.M.J. (TU Delft ImPhys/Verweij group; TU Delft ImPhys/Medical Imaging; TNO)","","2024","The accurate determination of the transfer function of ultrasound transducers is important for their design and operational performance. However, conventional methods for quantifying the transfer function, such as hydrophone measurements, radiation force balance, and pulse-echo measurements, are costly and complex due to specialized equipment required. In this study, we introduce a novel approach to estimate the transfer function of ultrasound transducers by measuring the acoustic streaming velocity generated by the transducer. We utilize an experimental setup consisting of a water tank with a millimeter scale, an ink-filled syringe, and a camera for recording the streaming phenomenon. Through streaming velocity measurements in the frequency range from 2 to 8 MHz, we determined the transfer function of an unfocused circular transducer with a center frequency of 5 MHz and a radius of 5.6 mm. We compared the performance of our method with hydrophone and pulse-echo measurements. At the center frequency, we measured a transmit efficiency of 1.9 kPa/V using the streaming approach, while hydrophone and pulse-echo measurements yielded transmit efficiencies of 2.1 kPa/V and 1.8 kPa/V, respectively. These findings demonstrate that the proposed method for estimating the transfer function of ultrasound transducers achieves a sufficient level of accuracy comparable to pulse-echo and hydrophone measurements.","Acoustic streaming; Reciprocity; Safety; Sensitivity; Transfer function; Ultrasound transducer","en","journal article","","","","","","","","","","","ImPhys/Verweij group","","",""
"uuid:cc836d20-cee2-4a1e-9c1e-5107fbfe54ec","http://resolver.tudelft.nl/uuid:cc836d20-cee2-4a1e-9c1e-5107fbfe54ec","Magnetic fluid film enables almost complete drag reduction across laminar and turbulent flow regimes","Stancanelli, L.M. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; ETH Zürich; Swiss Federal Institute for Forest, Snow and Landscape Research); Secchi, Eleonora (ETH Zürich); Holzner, Markus (Swiss Federal Institute for Forest, Snow and Landscape Research; Swiss Federal Institute of Aquatic Science and Technology; BOKU-University of Natural Resources and Life Sciences)","","2024","In the race to curb energy and oil consumption, zeroing of wall frictional forces is highly desirable. The turbulent skin friction drag at the solid/liquid interface is responsible for substantial energy losses when conveying liquids through hydraulic networks, contributing approximately 10% to the global electric energy consumption. Despite extensive research, efficient drag reduction strategies effectively applicable in different flow regimes are still unavailable. Here, we use a wall-attached magnetic fluid film to achieve a wall drag reduction of up to 90% in channel flow. Using optical measurements supported by modelling, we find that the strong damping of wall friction emerges from the co-existence of slip and waviness at the coating interface, and the latter is a key factor to obtain almost complete wall drag reduction across laminar and turbulent flow regimes. Our magnetic fluid film is promising and ready to be applied in energy-saving and antifouling strategies in fluid transport and medical devices.","","en","journal article","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:b2ef9acd-9738-431d-a368-a0069ddf756d","http://resolver.tudelft.nl/uuid:b2ef9acd-9738-431d-a368-a0069ddf756d","Sediment fluxes within salt marsh tidal creek systems in the Yangtze Estuary","Sun, J. (TU Delft Coastal Engineering; East China Normal University); van Prooijen, Bram (TU Delft Coastal Engineering); Wang, Xianye (East China Normal University); Zhao, Zhonghao (East China Normal University); He, Qing (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2024","Creeks are essential for salt marshes by conveying water and sediment through this geomorphic system. In this paper, we investigate the mechanisms that determine the residual sediment flux using measurements conducted in tidal creeks in salt marshes of the Yangtze Estuary. A main creek and a secondary creek were studied to explore whether the mechanisms determining residual sediment fluxes through the main creek differ from those in the secondary creek. Measurements in creeks were carried out over 5 years, spanning different months. Sediment import was found during most tides, both in the main creek and the secondary creek, implying that creeks in Chongming generally function as a conveyor belt of sediment into the marsh. However, sediment export can occur during certain overbank tides. When comparing the role of creeks in drainage and sediment delivery, the main creek functions more in delivering sediment while the secondary creek primarily serves as a drainage conduit. To better understand the mechanisms behind sediment fluxes, the residual sediment flux was compared with the residual discharge and the sediment differential (differences in sediment concentration between flood and ebb). Overbank tides generally lead to a net outward discharge as more water from saltmarshes can be concentrated into the marsh creek during ebb tides. This net outward discharge tends to export more sediment during ebb tides. However, due to the sediment abundance during the flood phase in the turbid environment, sediment import can be expected even with the residual export of water. Export of sediment was only found for the few tides with a net outward discharge and a small positive sediment concentration differential. Large negative sediment differentials (larger averaged suspended sediment concentration during ebb tides) have not been observed because the sediment supply during ebb is limited. This paper unravels how the sediment differential and residual discharge contribute to the residual sediment flux, providing a better understanding of sediment dynamics in marsh creek systems.","Marsh creek systems; Sediment availability; Sediment flux","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-04","","","Coastal Engineering","","",""
"uuid:91285ba8-2d88-442a-a3bb-364c0718947b","http://resolver.tudelft.nl/uuid:91285ba8-2d88-442a-a3bb-364c0718947b","Macro-dipoles in soft/hard expanded-polytetrafluoroethylene + fluoroethylenepropylene (ePTFE + FEP) fluoropolymer-film systems for high-output piezoelectric ferroelectret-transducer applications","Wang, Ningzhen (Beijing Forestry University; University of Connecticut); Baferani, Mohamadreza Arab (University of Connecticut); Daniels, Robert (University of Connecticut); Wu, Chao (University of Connecticut); Huo, Jindong (University of Connecticut); van Turnhout, J. (TU Delft Team Erik Offerman); Sotzing, Gregory A. (University of Connecticut); Gerhard, Reimund (University of Potsdam); Cao, Yang (University of Connecticut)","","2024","Multi-layer ferroelectrets consisting of fluoroethylenepropylene (FEP) copolymer and open-porous expanded polytetrafluoroethylene (ePTFE) films exhibit stable internal electret charges, high piezoelectric coefficients and heat resistance, making them promising candidates for wearable sensors or nanogenerators in body-area networks. Here, three- and five-layer (FEP/ePTFE/FEP and FEP/ePTFE/FEP/ePTFE/FEP) ferroelectret stacks were laminated and poled in a corona discharge. The resulting charge distributions were measured by use of the pulsed electro-acoustic (PEA) method and revealed that charges of opposite polarity were trapped at the interfaces between the FEP and ePTFE layers. Thus, the existence of one macro-dipole in the three-layer structure and of two macro-dipoles in the five-layer structure was directly shown for the first time. Moreover, electric-displacement-versus-electric-field (D-E) loops revealed that remnant polarization is given by the number of macro-dipoles in the respective stack. Due to the addition of the macro-dipoles, the piezoelectric d 33 coefficient of the FEP/ePTFE/FEP/ePTFE/FEP stack reaches 200 pC/N even under a potentially non-uniform compression of the soft ePTFE layers. The results should be useful for a better understanding and a performance optimization of ferroelectrets in self-powered intelligent devices.","charge distribution; charge-spring model; ePTFE + FEP ferroelectret; piezoelectricity","en","journal article","","","","","","","","2024-07-11","","","Team Erik Offerman","","",""
"uuid:938703d4-2480-4b85-b64f-eb5cf326aec0","http://resolver.tudelft.nl/uuid:938703d4-2480-4b85-b64f-eb5cf326aec0","Modeling the joint choice behavior of commuters’ travel mode and parking options for private autonomous vehicles","Xue, Fei (Beijing Jiaotong University); Yao, Enjian (Beijing Jiaotong University); Cherchi, Elisabetta (Newcastle University); Correia, Gonçalo (TU Delft Transport and Planning)","","2024","Difficulty in finding parking spaces and high parking fees discourage private car usage. Fully autonomous vehicles (AVs) capable of self-parking away from destinations will likely remove this barrier. Despite extensive survey-based research on AVs in recent years, existing literature has not sufficiently addressed the potential impact of new parking options on the demand for these vehicles. This study explores commuters’ joint choice of travel mode and parking for private autonomous vehicles (PAVs). To this end, a stated choice (SC) experiment was designed and deployed in the city of Beijing, China. Attitudinal statements were also designed to measure four latent variables: perceived ease of use, perceived usefulness, perceived safety, and attitude toward waiting. Using a hybrid choice model framework, the estimation results reveal that the choice of letting the PAV self-park at a non-destination location is significantly influenced by the location of such parking, the potential delay in re-taking the vehicle, and the fuel/energy consumption to and from the non-destination parking place. Attitudes toward AVs also play a crucial role, with perceived safety and perceived usefulness having the greatest impact. Our results can help managers and planners understand how PAVs affect people's travel mode choices and the corresponding parking options and assist them in developing strategies in preparation for the widespread use of AVs.","Attitudes; Automated vehicles; Hybrid choice model; Parking; Stated choice experiment; Willingness to pay","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-12","","","Transport and Planning","","",""
"uuid:19bfc28c-5b57-43be-8960-1c15f582f946","http://resolver.tudelft.nl/uuid:19bfc28c-5b57-43be-8960-1c15f582f946","Dynamics of freight transport decarbonization: A simulation study for Brazil","Ghisolfi, Verônica (Universidade Federal do Rio de Janeiro); Tavasszy, Lorant (TU Delft Transport and Planning); Correia, Gonçalo (TU Delft Transport and Planning); de Lorena Diniz Chaves, Gisele (Federal University of Santa Catarina); Mattos Ribeiro, Glaydston (Universidade Federal do Rio de Janeiro)","","2024","Freight transport decarbonization is challenging due to the slow implementation of policies to meet climate goals. This paper analyzes the dynamics of the implementation of freight decarbonization measures. A System Dynamics model was developed and applied to the Brazilian freight system to simulate the use of more sustainable modes and means of transport, including electrification, increased use of biofuels, acceleration of fleet renewal, and modal shift. Significant emission reductions are found in the scenarios combining a shift to alternative modes and a rapid phase-out of diesel vehicles. Even so, the Brazilian freight sector's emission budgets towards limiting global warming to 1.5 °C and 2 °C will be depleted during the current and next decade, respectively. An absolute reduction of carbon emissions before 2050 seems unlikely. Besides confirming the need to study the dynamics of the freight system, the findings corroborate the urgency for stronger actions on freight decarbonization.","Decarbonization; Freight transport; Policy implementation; System dynamics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-15","","","Transport and Planning","","",""
"uuid:79e91102-4da0-451a-bfc3-91a951d79d34","http://resolver.tudelft.nl/uuid:79e91102-4da0-451a-bfc3-91a951d79d34","Junction temperature and luminous flux prediction for white LED array based on electrical-photo-thermal modeling","Liu, Minne (Fudan University); Li, Wenyu (Fudan University); Chen, Wei (Fudan University); Ibrahim, Mesfin S. (New Territories); Xiong, Jingkang (Changzhou Institute of Technology Research for Solid State Lighting); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Fan, Jiajie (Fudan University; Fudan Zhangjiang Institute; Chinese Academy of Sciences)","","2024","During the operation of an LED array, its thermal and optical performances are always not equal to the superposition of the individual LED's characteristics because of a significant thermal coupling effect between the arrays. Based on this, this paper proposes an electrical–photo-thermal model, with considering both junction temperature and luminous flux, to predict the both the thermal and optical performances of LED arrays operated under different currents, case temperatures, and lighting methods. The junction temperature and luminous flux of a single LED operating under different driving currents and case temperature conditions are firstly collected to establish the luminous flux response surface model of a single chip. Then it is used to predict the luminous flux of an array, whose junction temperature is predicted using both thermal coupling matrix (TCM) and numerical models. Experiments verify the luminous flux of the LED array under different operation conditions and show that the proposed electrical–photo-thermal modeling can be used to predict the thermal and optical parameters of LED arrays with 95 % accuracy. Thus, it is effective for the fast prediction of the junction temperature and luminous flux of large LED systems with array structures, i.e. intelligent automotive lightings and displays.","Electrical-photo-thermal modeling; Junction temperature; Light-emitting diode; Luminous flux; Multiple-chip array; Thermal coupling","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:0d2333eb-1a2a-4810-a6ff-2c3f1997b2f6","http://resolver.tudelft.nl/uuid:0d2333eb-1a2a-4810-a6ff-2c3f1997b2f6","Enhancing colloid stability of polymer microspheres in water through SiO2 coating: Effects of coating cycles and surface coverage","Kamphorst, R. (TU Delft ChemE/Product and Process Engineering); Wanjari, Pratyush (Student TU Delft); Saedy, S. (TU Delft ChemE/Product and Process Engineering); van Dam, Julia F.K. (Student TU Delft); Thijssen, A. (TU Delft Microlab); Brüner, Philipp (ION-TOF, Munster); Grehl, Thomas (ION-TOF, Munster); Meesters, G.M.H. (TU Delft ChemE/Product and Process Engineering); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering)","","2024","In this study, we investigated the wettability and agglomeration characteristics of polymer microspheres coated with low-temperature deposited SiO2 in a fluidized bed atomic layer deposition (ALD) setup. Surface characterization revealed the presence of a significant amount of deposited Si-OH groups within the first cycles. A drastic decrease in agglomerate size, water contact angle (WCA), and droplet absorption time of the powder was observed when coating was applied. Furthermore, we observed an increase in the amount of Si-OH present on the particle surface with increasing coating cycles, while no significant improvement in water affinity was found after the first coating cycles. Our findings suggest that surface coverage is the primary factor in improving the colloid stability of particles, coated at low temperatures. The low temperature operation of our system introduced a chemical vapor deposition (CVD) component to our coating process, which allowed full surface coverage to be achieved within the first two coating cycles.","Agglomeration; Atomic layer deposition; Chemical vapor deposition; Surface functionalization; Wettability","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:7ab42167-5443-44e5-9d78-df162057e571","http://resolver.tudelft.nl/uuid:7ab42167-5443-44e5-9d78-df162057e571","Precursor- and waste-free synthesis of spark-ablated nanoparticles with enhanced photocatalytic activity and stability towards airborne organic pollutant degradation","Drdova, Sarka (ETH Zürich; Swiss Federal Laboratories for Materials Science and Technology (Empa)); Gao, Min (ETH Zürich; Swiss Federal Laboratories for Materials Science and Technology (Empa)); Sambalova, Olga (Swiss Federal Laboratories for Materials Science and Technology (Empa)); Pauer, Robin (Swiss Federal Laboratories for Materials Science and Technology (Empa)); Zhou, Zhouping (Student TU Delft); Dimitriadou, Sofia (VSPARTICLE); Schmidt-Ott, A. (TU Delft ChemE/Materials for Energy Conversion and Storage; VSPARTICLE); Wang, J. (ETH Zürich; Swiss Federal Laboratories for Materials Science and Technology (Empa))","","2024","Photocatalyst synthesis typically involves multiple steps, expensive precursors, and solvents. In contrast, spark ablation offers a simple process of electrical discharges in a gap between two electrodes made from a desirable material. This enables a precursor- and waste-free generation of pure metal oxide nanoparticles or mixtures of various compositions. This study presents a two-step method for the production of photocatalytic filters with deposited airborne MnOx, TiO2, and ZnO nanoparticles using spark ablation and calcination processes. The resulting MnOx and TiO2 filters demonstrated almost twice the activity with outstanding performance stability, as compared to sol-gel MnO2 and commercial TiO2. The introduced method is not only simple, precursor- and waste-free, and leads to superior performance for the case studied, but it also has future potential due to its versatility. It can easily produce mixed and doped materials with further improved properties, making it an interesting avenue for future research.","","en","journal article","","","","","","","","","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:95ef7374-1908-4ebd-81fe-c042d7f3b2d3","http://resolver.tudelft.nl/uuid:95ef7374-1908-4ebd-81fe-c042d7f3b2d3","Eddy-Induced Dispersion of Sea Ice Floes at the Marginal Ice Zone","Gupta, M. (TU Delft Physical and Space Geodesy; California Institute of Technology); Gürcan, Emma (California Institute of Technology); Thompson, Andrew F. (California Institute of Technology)","","2024","Ocean heat exchanges at the marginal ice zone (MIZ) play an important role in melting sea ice. Mixed-layer eddies transport heat and ice floes across the MIZ, facilitating the pack's access to warm waters. This study explores these frontal dynamics using disk-shaped floes coupled to an upper-ocean model simulating the sea ice edge. Numerical experiments reveal that small floes respond more strongly to fine-scale ocean currents, which favors higher dispersion rates and weakens sea ice drag onto the underlying ocean. Floes with radii smaller than resolved turbulent filaments (∼2–4 km) result in a wider and more energetic MIZ, by a factor of 70% each, compared to larger floes. We hypothesize that this floe size dependency may affect sea ice break-up by controlling oceanic energy propagation into the MIZ and modulate the sea ice pack's melt rate by regulating lateral heat transport toward the sea ice cover.","eddies; heat transport; oceanography; polar climate; sea ice; submesoscale","en","journal article","","","","","","","","","","","Physical and Space Geodesy","","",""
"uuid:d4c2f44f-2429-4c7a-835b-9792e58541e2","http://resolver.tudelft.nl/uuid:d4c2f44f-2429-4c7a-835b-9792e58541e2","Evaluating real-world emissions from in-use buses and taxis using on-road remote sensing","Middela, Mounisai Siddartha (Trinity College Dublin); Mahesh, S. (TU Delft Transport and Planning); McNabola, Aonghus (Trinity College Dublin); Smith, William (University College Dublin); Timoney, David (University College Dublin); Ekhtiari, Ali (University College Dublin); Fowler, Ben (Ricardo Energy and Environment); Willis, Paul (Ricardo Energy and Environment); Rose, Rebecca (Ricardo Energy and Environment)","","2024","Assessing real-world emissions from buses and taxis is vital to comprehend their impact on urban air quality. Such vehicles differ significantly from the majority of the fleet owing to their higher mileage rates. However, few studies have focused on specifically assessing the emissions from this segment of the vehicle fleet. In this context, this study evaluated the real-world emissions of nitrogen oxides (NOx) from in-use buses and taxis in Dublin, Ireland, using crossroad remote sensing technology. The remote sensing system was deployed at strategic locations throughout the city to capture on-road emissions from passing vehicles. The collected data included vehicle related information such as emission standard, make, and mileage, and pollutants including NOx. Based on this data, analysis was aimed to understand the impact of Euro emission standard, ambient temperature, mileage, and make of the vehicle on NOx emissions. The results reveal that the average emissions from taxis reduce by 37% from Euro 5 to Euro 6b, and average emissions from Euro 6 buses are 87% lower compared to Euro 5. The trends in emission factors (EFs) of buses and taxis were similar during summer and winter sampling. Moreover, on comparing the emissions from the top five taxi manufacturers, different trends in the emission factors were observed. Finally, the study found that the effect of vehicle mileage on emissions was unclear for both buses and taxis. In any case, these findings provide valuable insights into the real-world emission performance of the existing fleet of buses and taxis in Dublin and highlight the need for targeted measures to reduce emissions from these vehicles. The results can assist policymakers and urban planners in formulating evidence-based strategies to improve air quality in Dublin and other cities facing similar challenges.","Buses; Euro-6 regulation; In-use surveillance; On-road vehicle emissions; Remote sensing; Taxis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-08","","","Transport and Planning","","",""
"uuid:e0759412-1437-4585-8227-5a2c1ae92981","http://resolver.tudelft.nl/uuid:e0759412-1437-4585-8227-5a2c1ae92981","Modelling and analysis of the horizontal configuration of tidal fences in barrages","Verbeek, Merel C. (TU Delft Environmental Fluid Mechanics); Talstra, H. (Svašek Hydraulics); Labeur, R.J. (TU Delft Environmental Fluid Mechanics); Uijttewaal, W.S.J. (TU Delft Environmental Fluid Mechanics)","","2024","Tidal stream turbines are becoming an affordable option for harvesting sustainable energy in coastal areas. They can be retrofitted in barrages, providing an integral solution for flood protection and emission-free power generation, within environmental constraints. To optimize the turbine-barrage configuration with respect to these objectives, simulation tools are needed to predict the efficiency of the turbines as well as their impact on the adjacent tidal system. These tools should be based on an accurate representation of the underlying flow processes, which cover a wide range of spatial scales — from meters at the barrage and turbines to tenths of kilometers in the tidal basin. This article presents the development of such a tool by linking an analytical model for turbine fences in barrage gates to a regional flow model. The turbine model is validated with experimental data, and data from a thoroughly monitored tidal energy pilot project. Simulations reveal how clustering the turbines in small arrays can increase their efficiency, owing to array blockage effects, with only little effect on the tidal exchange. We also demonstrate the potential of using turbine fences to manipulate the tidal jet, issued from the barrage, with benefits for coastal — and wildlife protection in the basin. The presented research helps understanding how turbine fences in barrages can be configured with high energy yield and calculated impact to the environment.","Modelling; Sub-grid calculation; Tidal barrage; Tidal basin hydrodynamics; Tidal fences","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:eb877982-c12d-4b22-9695-bf253a03febd","http://resolver.tudelft.nl/uuid:eb877982-c12d-4b22-9695-bf253a03febd","Calculating Thermodynamic Factors for Diffusion Using the Continuous Fractional Component Monte Carlo Method","Hulikal Chakrapani, T. (TU Delft Reservoir Engineering); Hajibeygi, H. (TU Delft Reservoir Engineering); Moultos, O. (TU Delft Engineering Thermodynamics); Vlugt, T.J.H. (TU Delft Engineering Thermodynamics)","","2024","Thermodynamic factors for diffusion connect the Fick and Maxwell-Stefan diffusion coefficients used to quantify mass transfer. Activity coefficient models or equations of state can be fitted to experimental or simulation data, from which thermodynamic factors can be obtained by differentiation. The accuracy of thermodynamic factors determined using indirect routes is dictated by the specific choice of an activity coefficient model or an equation of state. The Permuted Widom’s Test Particle Insertion (PWTPI) method developed by Balaji et al. enables direct determination of thermodynamic factors in binary and multicomponent systems. For highly dense systems, for example, typical liquids, it is well known that molecular test insertion methods fail. In this article, we use the Continuous Fractional Component Monte Carlo (CFCMC) method to directly calculate thermodynamic factors by adopting the PWTPI method. The CFCMC method uses fractional molecules whose interactions with their surrounding molecules are modulated by a coupling parameter. Even in highly dense systems, the CFCMC method efficiently handles molecule insertions and removals, overcoming the limitations of the PWTPI method. We show excellent agreement between the results of the PWTPI and CFCMC methods for the calculation of thermodynamic factors in binary systems of Lennard-Jones molecules and ternary systems of Weeks-Chandler-Andersen molecules. The CFCMC method applied to calculate the thermodynamic factors of realistic molecular systems consisting of binary mixtures of carbon dioxide and hydrogen agrees well with the NIST REFPROP database. Our study highlights the effectiveness of the CFCMC method in determining thermodynamic factors for diffusion, even in densely packed systems, using relatively small numbers of molecules.","","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:cd712934-9c98-42eb-b7a7-cd5f57273857","http://resolver.tudelft.nl/uuid:cd712934-9c98-42eb-b7a7-cd5f57273857","A 3D time-dependent backward erosion piping model","Pol, J.C. (TU Delft Hydraulic Structures and Flood Risk; HKV); Noordam, Aron (Deltares); Kanning, W. (TU Delft Hydraulic Structures and Flood Risk; Deltares)","","2024","Backward erosion piping (BEP) is a failure mechanism of hydraulic structures like dams and levees on cohesionless foundations subjected to seepage flows. This article models the time-dependent development of BEP using numerical simulation of the erosion process. A 3-dimensional finite element equilibrium BEP model is extended with a formulation for the sediment transport rate. The model is compared to and calibrated with small- and large-scale experiments. Finally, a large set of simulations is analyzed to study the effects of factors such as grain size, scale (seepage length) and overloading on the rate of pipe progression. The results show that the development of BEP in the small-scale experiments is predicted well. Challenges remain for the prediction at larger scales, as calibration and validation is hard due to limited large-scale experiments with sufficiently accurate measurements. The results show that the progression rate increases with grain size and degree of overloading and decreases with seepage length, which is consistent with experimental observations. The model results provide a better physical basis for incorporating time-dependent development in the risk assessment and design of levees.","Backward erosion piping; Finite elements; Internal erosion; Sediment transport","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:12eefbd7-466e-456e-b89c-fc0781971e53","http://resolver.tudelft.nl/uuid:12eefbd7-466e-456e-b89c-fc0781971e53","Shock-wave/turbulent boundary-layer interaction with a flexible panel","Laguarda, L. (TU Delft Aerodynamics); Hickel, S. (TU Delft Aerodynamics); Schrijer, F.F.J. (TU Delft Aerodynamics); van Oudheusden, B.W. (TU Delft Aerodynamics)","","2024","The dynamic coupling between a Mach 2.0 shock-wave/turbulent boundary-layer interaction (STBLI) and a flexible panel is investigated. Wall-resolved large-eddy simulations are performed for a baseline interaction over a flat-rigid wall, a coupled interaction with a flexible panel, and a third interaction over a rigid surface that is shaped according to the mean panel deflection of the coupled case. Results show that the flexible panel exhibits self-sustained oscillatory behavior over a broad frequency range, confirming the strong and complex fluid-structure interaction (FSI). The first three bending modes of the panel oscillation are found to contribute most to the unsteady panel response, at frequencies in close agreement with natural frequencies of the mean deformed panel rather than those for the unloaded flat panel. This highlights the importance of the mean panel deformation and the corresponding stiffening in the FSI dynamics. The time-averaged flow shows an enlarged reverse-flow region in the presence of mean surface deformations. The separation-shock unsteadiness is enhanced due to the panel motion, leading to higher wall-pressure fluctuations in the coupled interaction. Spectral analysis of the separation-shock location and bubble-volume signals shows that the STBLI flow strongly couples with the first bending mode of the panel oscillation. This is further confirmed by dynamic mode decomposition of the flow and displacement data, which reveals variations in the reverse-flow region that follow the panel bending motion and appear to drive the separation-shock unsteadiness. Low-frequency modes that are not associated with the fluid-structure coupling, in turn, are qualitatively similar to those obtained for the rigid-wall interactions, indicating that the characteristic low-frequency unsteadiness of STBLI coexists with the dynamics emerging from the fluid-structure coupling. Based on the present results, unsteady FSIs involving STBLIs and flexible panels are likely to accentuate rather than mitigate the undesirable features of STBLIs.","","en","journal article","","","","","","","","","","","Aerodynamics","","",""
"uuid:da798ae5-12dc-482c-93e0-bee795b5ac77","http://resolver.tudelft.nl/uuid:da798ae5-12dc-482c-93e0-bee795b5ac77","Inhibitory effects of long chain fatty acids on anaerobic sludge treatment: Biomass adaptation and microbial community assessment","Szabo Corbacho, M. (TU Delft Sanitary Engineering; IHE Delft Institute for Water Education; Laboratorio Tecnológico del Uruguay; Technological University of Uruguay); Sharma, Pragnya (IHE Delft Institute for Water Education); Míguez, Diana (Laboratorio Tecnológico del Uruguay); de la Sovera, Victoria (Ministry of Education); Brdjanovic, Damir (TU Delft BT/Environmental Biotechnology; IHE Delft Institute for Water Education); Etchebehere, Claudia (Ministry of Education); Garcia, H. (IHE Delft Institute for Water Education; Technological University of Uruguay); van Lier, J.B. (TU Delft Sanitary Engineering; IHE Delft Institute for Water Education)","","2024","The study investigated the effects of long-chain fatty acids (LCFA) on anaerobic sludge treating lipid-rich wastewater. It involved batch experiments with three sludge samples: two acclimated to lipids and one non-acclimated. The experiments aimed to observe the degradation of LCFA, specifically oleate and palmitate, by dosing them at concentrations ranging from 50 to 600 mg/L. Measurements of the cumulative methane production and the LCFA concentration, quantified as fat, oil, and grease (FOG) were performed. To ensure the sludge was free from other biodegradable substrates, part of the samples was pre-incubated without feed. The tests were conducted with both pre-incubated and non-incubated inoculum sludge. The findings revealed that oleate was degraded more efficiently than palmitate across all sludge samples, with a greater conversion rate to methane. Sludge samples acclimated to lipids showed a superior capacity to degrade LCFA compared to non-acclimated ones. It was noted that at concentrations above 400 mg/L, the conversion of LCFAs to intermediate compounds was inhibited, although this did not affect the subsequent methane production. The study concludes with a recommendation for sludge adaptation strategies to boost the efficiency of anaerobic wastewater treatment systems dealing with lipid-rich waste. The presence of LCFA-degrading bacteria families like Kosmotogaceae, Petrotogaceae, and Synergistaceae in the acclimated sludge samples underscores the adaptation and potential for improved degradation performance.","Anaerobic digestion; Lipids; Microbial community analysis; Sludge acclimation","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:e75d53c4-0252-4890-aae5-052e378e6da7","http://resolver.tudelft.nl/uuid:e75d53c4-0252-4890-aae5-052e378e6da7","Predicting marine and aeolian contributions to the Sand Engine's evolution using coupled modelling","van Westen, B. (TU Delft Hydraulic Engineering; Deltares); Luijendijk, Arjen (TU Delft Coastal Engineering; Deltares); de Vries, S. (TU Delft Coastal Engineering); Cohn, Nicholas (U.S. Army Engineer Research and Development Center); Leijnse, Tim W.B. (Deltares; Vrije Universiteit Amsterdam); de Schipper, M.A. (TU Delft Coastal Engineering)","","2024","Quantitative predictions of marine and aeolian sediment transport in the nearshore–beach–dune system are important for designing Nature-Based Solutions (NBS) in coastal environments. To quantify the impact of the marine-aeolian interactions on shaping NBS, we present a framework coupling three existing process-based models: Delft3D Flexible Mesh, SWAN and AeoLiS. This framework facilitates the continuous exchange of bed levels, water levels and wave properties between numerical models focussing on the aeolian and marine domain. The coupled model is used to simulate the morphodynamic evolution of the Sand Engine mega-nourishment. Results display good agreement with the observed aeolian and marine volumetric developments, showing similar marine-driven erosion from the main peninsula and aeolian-driven infilling of the dune lake. To estimate the magnitude of the interactions between aeolian and marine processes, a comparison between the simulated morphological development by the coupled and stand-alone models was made. This comparison shows that aeolian sediment transport to the foredune, i.e. 214,000 m3 over 5 years, extracts sediment from the marine domain. As a result, the alongshore redistribution of sediment from the main peninsula by marine-driven processes decreased by 70,000 m3, representing 1.7% of the total marine-driven dispersion. From the aeolian perspective, marine-driven deposition and erosion reshape the cross-shore profile, controlling the supply-limited aeolian sediment transport and the magnitude of sediment deposition in the foredunes. In the region with persistent accretion along the Sand Engine's southern flank, a higher than average foredune deposition was predicted due to morphological development of the region where sediment is picked up by aeolian transport. Including these marine processes in the coupled model resulted in an increase of 1.3% in foredune growth in year 1 and up to 6.7% in year 5 along this accretive section. At the northern flank, where the developing lagoon and tidal channel provided increased shelter to the supratidal beach, predicted foredune deposition reduced up to −11.5% over the evaluation period. Our findings show that both aeolian and marine transports impact reshaping the nourished sand, where developments in one domain affect the other. The study findings echo that the interplay between aeolian- and marine-driven morphodynamics could play a relevant role when predicting sandy NBS.","AeoLiS; Coupled modelling; Delft3D Flexible Mesh; Mega nourishment; Morphodynamics; Numerical modelling","en","journal article","","","","","","","","","","Hydraulic Engineering","Coastal Engineering","","",""
"uuid:72c4f3e2-a859-4c4d-9253-b32240e7de67","http://resolver.tudelft.nl/uuid:72c4f3e2-a859-4c4d-9253-b32240e7de67","Machine learning assisted discovery of high-efficiency self-healing epoxy coating for corrosion protection","Liu, Tong (University of Science and Technology Beijing; Shenyang University of Chemical Technology); Chen, Zhuoyao (University of Science and Technology Beijing); Yang, Jingzhi (University of Science and Technology Beijing); Ma, Lingwei (University of Science and Technology Beijing; Liaoning Academy of Materials); Mol, J.M.C. (TU Delft Team Arjan Mol); Zhang, Dawei (University of Science and Technology Beijing; Liaoning Academy of Materials)","","2024","Machine learning is a powerful means for the rapid development of high-performance functional materials. In this study, we presented a machine learning workflow for predicting the corrosion resistance of a self-healing epoxy coating containing ZIF-8@Ca microfillers. The orthogonal Latin square method was used to investigate the effects of the molecular weight of the polyetheramine curing agent, molar ratio of polyetheramine to epoxy, molar content of the hydrogen bond unit (UPy-D400), and mass content of the solid microfillers (ZIF-8@Ca microfillers) on the low impedance modulus (lg|Z|0.01Hz) values of the scratched coatings, generating 32 initial datasets. The machine learning workflow was divided into two stages: In stage I, five models were compared and the random forest (RF) model was selected for the active learning. After 5 cycles of active learning, the RF model achieved good prediction accuracy: coefficient of determination (R 2) = 0.709, mean absolute percentage error (MAPE) = 0.081, root mean square error (RMSE) = 0.685 (lg(Ω·cm2)). In stage II, the best coating formulation was identified by Bayesian optimization. Finally, the electrochemical impedance spectroscopy (EIS) results showed that compared with the intact coating ((4.63 ± 2.08) × 1011 Ω·cm2), the |Z|0.01Hz value of the repaired coating was as high as (4.40 ± 2.04) × 1011 Ω·cm2. Besides, the repaired coating showed minimal corrosion and 3.3% of adhesion loss after 60 days of neutral salt spray testing.","","en","journal article","","","","","","","","","","","Team Arjan Mol","","",""
"uuid:8261d3bc-950d-4af3-abe5-f17220d6e061","http://resolver.tudelft.nl/uuid:8261d3bc-950d-4af3-abe5-f17220d6e061","Model Predictive Control in buildings with thermal and visual comfort constraints","Khosravi, M. (TU Delft Team Khosravi); Huber, Benjamin (Swiss Federal Laboratories for Materials Science and Technology (Empa)); Decoussemaeker, Antoon (Swiss Federal Laboratories for Materials Science and Technology (Empa); ETH Zürich); Heer, Philipp (Swiss Federal Laboratories for Materials Science and Technology (Empa)); Smith, Roy S. (ETH Zürich)","","2024","Model Predictive Control can cope with conflicting control objectives in building energy managements. In terms of user satisfaction, visual comfort has been proven in several studies to be a crucial factor, however thermal comfort is typically considered the only important aspect. Besides human well-being, visual comfort strongly impacts the productivity of the occupants in offices. Therefore, from an economic point of view, it is essential to include visual comfort in Model Predictive Control for buildings. In this paper semi-linear support vector machine is applied to learn suitable models for visual comfort measured by Daylight Glare Probability. The resulting model is incorporated into a Model Predictive Control framework, together with an autoregressive exogenous model accounting for the thermal dynamics of the building. The approach is validated through an extensive numerical case study, and the benefits of including visual comfort and blind control in the Model Predictive Control problem are evaluated. We observe that the proposed Model Predictive Control scheme ensures both the thermal and visual comfort constraints at the expense of 2.2% to 7.2% higher energy consumption compared to the benchmark Model Predictive Control configuration, which considers only the thermal comfort constraints.","Building energy; Data predictive control; Daylight glare probability; Model predictive control; Thermal comfort; Visual comfort","en","journal article","","","","","","","","","","","Team Khosravi","","",""
"uuid:f2dbfa35-2dc2-42bd-8213-2b52907d311a","http://resolver.tudelft.nl/uuid:f2dbfa35-2dc2-42bd-8213-2b52907d311a","Liquid-Liquid-Gas Triphasic Hydrogenation of Bicarbonate to Formate in a Continuous Flow Tubular Reactor","Afreen, G. (TU Delft ChemE/Catalysis Engineering); Bansode, Atul (TU Delft ChemE/Catalysis Engineering); Wada, Kazuhito (Nitto Denko Corporation); Hirano, Makoto (Nitto Denko Corporation); Matsuda, Hirokazu (Nitto Denko Corporation); Urakawa, A. (TU Delft ChemE/Catalysis Engineering)","","2024","Multiphasic reaction of bicarbonate hydrogenation to form formate using homogeneous Ru PNP pincer catalyst in a continuous flow tubular reactor is reported. The reaction system consists of three phases. Catalyst is dissolved in toluene while potassium bicarbonate is dissolved in water. The significance of efficient mixing among the organic phase, aqueous phase and gaseous hydrogen to improve hydrogenation reaction by using different inert packing materials is studied by operando visualization and also quantitatively discussed. The bicarbonate conversion of up to 67% is achieved after optimization of important reaction and reactor parameters. The designed reactor setup comprised of effective recycling system that recycles the catalyst with >99% activity.","CO hydrogenation; Formic acid; Homogeneous catalyst; Packed-bed reactor; Triphasic reaction","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:8532d5c0-316e-48a0-b8eb-9e7bce2cf2d2","http://resolver.tudelft.nl/uuid:8532d5c0-316e-48a0-b8eb-9e7bce2cf2d2","Electrogenic sulfur oxidation by cable bacteria in two seasonally hypoxic coastal systems","Burdorf, Laurine D.W. (Universiteit Antwerpen); Cook, Perran L.M. (Monash University); Robertson, Elizabeth K. (University of Gothenburg; University of Southern Denmark); Tramper, Anton (NIOZ Royal Netherlands Institute for Sea Research); Hidalgo-Martinez, Silvia (Universiteit Antwerpen); Vasquez-Cardenas, Diana (Universiteit Antwerpen); Malkin, Sairah Y. (University of Maryland Center for Environmental Science); Meysman, F.J.R. (TU Delft BT/Environmental Biotechnology; Universiteit Antwerpen)","","2024","Cable bacteria can reach high densities in coastal sediments, and as a result of their unusual electrogenic lifestyle and intense metabolic activity, exert a major and distinct impact on biogeochemical cycling, both locally in sediments and at the ecosystem level. This appears to be particularly true for seasonally hypoxic systems, but the driving force behind the proliferation of cable bacteria in these systems is not well understood. Moreover, the metabolism of cable bacteria induces strong acid production, which can be buffered through carbonate dissolution in sediments. A strong depletion of alkalinity in the pore water is therefore expected in carbonate-poor sediments. To evaluate the impact of cable bacteria metabolism on sediment geochemistry, we performed field sampling and laboratory sediment incubations in two seasonally hypoxic sites: one carbonate-poor site with low levels of free sulfide in pore water (Yarra Estuary, Australia) and one carbonate-rich site with high free sulfide (Lake Grevelingen, The Netherlands). Active cable bacteria populations were found in both field locations, with higher abundance and activity observed in spring compared to autumn. The sediment incubations tracked the metabolic activity of cable bacteria over time (maximum 84 days), and confirmed the fast development of an electric network (cell doubling time: ∼19 h). These results suggest that cable bacteria are widespread in seasonally hypoxic systems, supporting previous findings. Cable bacteria acidified the sediment by > 1.5 pH units in 6–13 days (differing per site) and their activity accounted for >70% of the oxygen uptake. A clear subsurface accumulation of Fe2+ was observed after 8 days of Yarra sediment incubations, indicative of increased FeS dissolution as e-SOx developed. The increased availability of sulfide from FeS dissolution promotes a positive-feedback loop that we infer allowed for a faster development of cable bacteria in the carbonate-poor sediments. A depletion of total alkalinity was observed in the deeper Yarra sediment, whereas, a higher alkalinity efflux was previously observed in the carbonate-rich sediments from Lake Grevelingen. These results suggest a differential pH and alkalinity dynamic due to the interaction between the local carbonate content of the sediment and cable bacteria activity.","Alkalinity; Aquatic biogeochemistry; Cable bacteria; Iron cycling; Long-distance electron transport; Sediment buffering capacity","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-03","","","BT/Environmental Biotechnology","","",""
"uuid:e7444ac1-5c3b-4901-a940-986f3962debb","http://resolver.tudelft.nl/uuid:e7444ac1-5c3b-4901-a940-986f3962debb","A study on siting of emergency shelters for dam failure floods considering population distribution and weather effects","Jiao, Yutie (Zhengzhou University); Li, Zongkun (Zhengzhou University); Ge, Wei (Zhengzhou University; Yellow River Engineering Consulting Co); Jing, Laihong (Yellow River Engineering Consulting Co); Wu, Meimei (Henan University of Technology, Zhengzhou); Wang, Te (Zhengzhou University); Sun, Heqiang (Zhengzhou University); Wang, Jianyou (Zhengzhou University); Zhang, Xiangyang (Zhengzhou University); van Gelder, P.H.A.J.M. (TU Delft Safety and Security Science)","","2024","In recent years, dam failures have occurred frequently because of extreme weather, posing a significant threat to downstream residents. The establishment of emergency shelters is crucial for reducing casualties. The selection of suitable shelters depends on key information such as the number and distribution of affected people, and the effective capacity and accessibility of the shelters. However, previous studies on siting shelters did not fully consider population distribution differences at a finer scale. This limitation hinders the accuracy of estimating the number of affected people. In addition, most studies ignored the impact of extreme rainfall on the effective capacity and accessibility of shelters, leading to a low applicability of the shelter selection results. Therefore, in this study, land-use and land-cover change (LUCC) and nighttime lighting data were used to simulate population distribution and determine the number and distribution of affected people. Qualified candidate shelters were obtained based on screening criteria, and their effective capacity and accessibility information under different weather conditions were quantified. Considering factors such as population transfer efficiency, construction cost and shelter capacity constraints, a multi-objective siting model was established and solved using the non-dominated sorting genetic algorithm II (NSGA- II) to obtain the final siting scheme. The method was applied to the Dafangying Reservoir, and the results showed the following: (1) The overall mean relative error (MRE) of the population in the 35 downstream streets was 11.16 %, with good fitting accuracy. The simulation results truly reflect the population distribution. (2) Normal weather screening generated 352 qualified candidate shelters, whereas extreme rainfall weather screening generated 266 candidate shelters. (3) Based on the population distribution and weather factors, four scenarios were set up, with 63, 106, 73, and 131 shelters selected. These two factors have a significant impact on the selection of shelters and the allocation of evacuees, and should be considered in the event of a dam-failure floods.","Dam-failure floods; Emergency transfer; Population distribution; Shelters selection; Weather factors","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-05","","","Safety and Security Science","","",""
"uuid:974e9c7f-2187-435c-a287-8dd52dc316a1","http://resolver.tudelft.nl/uuid:974e9c7f-2187-435c-a287-8dd52dc316a1","Variability of Middle East springtime dust events between 2011 and 2022","Broomandi, Parya (Nazarbayev University); Galán-Madruga, David (Instituto de Salud Carlos III); Satyanaga, Alfrendo (Nazarbayev University); Hamidi, Mehdi (Babol Noshirvani University of Technology); Ledari, Dorna Gholamzade (University of Tehran); Fathian, Aram (Rheinisch-Westfälische Technische Hochschule; University of Calgary; Research Institute for Earth Sciences); Sarvestan, Rasoul (Hakim Sabzevari University); Janatian Ghadikolaei, N. (TU Delft Geo-engineering; Tallinn University of Technology); Jahanbakhshi, Ali (Loughborough University)","","2024","The Middle East frontal sand and dust storms (SDS) occur in non-summer seasons, and represent an important phenomenon of this region’s climate. Among the mentioned type, spring SDS are the most common. Trend analysis was used in the current study to investigate the spatial-temporal variability of springtime dust events in the Middle East using synoptic station observation from 2011 to 2022. The plausible changes in some controlling factors of dust activity at selected important dust sources in the Middle East were also studied during this time period. Our results showed a statistically significant spike in springtime dust events across the Middle East, particularly in May 2022. To evaluate the relative importance of controlling factors, the applied feature of importance analysis using random forest (RF) showed the higher relative importance of topsoil layer wetness, surface soil temperature, and surface wind speed in dust activity over the Middle East between 2011 and 2022. Long-term trend analysis of topsoil moisture and temperature, using the Mann-Kendall trend test, showed a decrease in soil moisture and an increase in soil temperature in some selected important dust sources in the Middle East. Moreover, our predictions using ARIMA models showed a high tendency to dust activities in selected major dust origins (domain 2 and domain 5) with a statistically significant increase (p-value < 0.05) between 2023 and 2029. Observed spatial and temporal changes within SDS hotspots can act as the first step to build up for the first time an SDS precise intensity scale, as well as establishing an SDS early warning system in future.","ARIMA model; Drought; Mann-Kendall trend test; Sand and dust storms; Soil moisture; Soil temperature; the Middle East","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-27","","","Geo-engineering","","",""
"uuid:77c530c0-d30e-4ea3-b3af-ac0d7f31171a","http://resolver.tudelft.nl/uuid:77c530c0-d30e-4ea3-b3af-ac0d7f31171a","Revisiting the Past: A comparative study for semantic segmentation of historical images of Adelaide Island using U-nets","Dahle, F. (TU Delft Physical and Space Geodesy); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing); Wouters, B. (TU Delft Physical and Space Geodesy)","","2024","The TriMetrogon Aerial (TMA) archive is an archive of historical images of Antarctica taken by the US Navy between 1940 and 2000 with analogue cameras. The analysis of such historic data can give a view of Antarctica's glaciers predating modern satellite imagery and provide unique insights into the long-term impact of changing climate conditions with essential validation data for climate modelling. However, the lack of semantic information for these images presents a challenge for large-scale computer-driven analysis. Such information can be added to the data using semantic segmentation, but traditional algorithms fail on these scanned historical grayscale images, due to varying image quality, lack of colour information and artefacts in the images. To address this, we present a deep-learning-based U-net workflow. Our approach includes creating training data by pre-processing and labelling the raw images. Furthermore, different versions of the U-net are trained to optimize its hyperparameters and augmentation methods. With the optimal hyper-parameters and augmentation methods, a final model has been trained for a use-case to segment 118 images covering Adelaide Island. We tested our approach by segmenting challenging historical images using a U-net model with just 80 training images, achieving an accuracy of 73% for 20 validation images. While no test data is available for our use case, a visual examination of the segmented images shows that our method performs effectively. The comparison of the hyper-parameters and augmentation methods provides directions for training other U-net-based models so that the presented workflow can be used to segment other archives with historical imagery. Additionally, the labelled training data and the segmented images of the test are publicly available at https://github.com/fdahle/antarctic_segmentation.","","en","journal article","","","","","","","","","","","Physical and Space Geodesy","","",""
"uuid:8d0a9d4d-7064-406a-aa16-1f41863f7f26","http://resolver.tudelft.nl/uuid:8d0a9d4d-7064-406a-aa16-1f41863f7f26","Tuning Nanopores in Tubular Ceramic Nanofiltration Membranes with Atmospheric-Pressure Atomic Layer Deposition: Prospects for Pressure-Based In-Line Monitoring of Pore Narrowing","Nijboer, Michiel (University of Twente); Jan, A. (TU Delft Sanitary Engineering); Chen, M. (TU Delft ChemE/Product and Process Engineering; University of Twente); Batenburg, Kevin (University of Twente); Peper, Julia (University of Twente); Aarnink, Tom (University of Twente); Roozeboom, Fred (University of Twente); Kovalgin, Alexey (University of Twente); Nijmeijer, Arian (University of Twente); Luiten-Olieman, Mieke (University of Twente)","","2024","Atomic layer deposition (ALD) is known for its unparalleled control over layer thickness and 3D conformality and could be the future technique of choice to tailor the pore size of ceramic nanofiltration membranes. However, a major challenge in tuning and functionalizing a multichannel ceramic membrane is posed by its large internal pore volume, which needs to be evacuated during ALD cycling. This may require significant energy and processing time. This study presents a new reactor design, operating at atmospheric pressure, that is able to deposit thin layers in the pores of ceramic membranes. In this design, the reactor wall is formed by the industrial tubular ceramic membrane itself, and carrier gas flows are employed to transport the precursor and co-reactant vapors to the reactive surface groups present on the membrane surface. The layer growth for atmospheric-pressure ALD in this case proceeds similarly to that for state-of-the-art vacuum-based ALD. Moreover, for membrane preparation, this new reactor design has three advantages: (i) monolayers are deposited only at the outer pore mouths rather than in the entire bulk of the porous membrane substrate, resulting in reduced flow resistances for liquid permeation; (ii) an in-line gas permeation method was developed to follow the layer growth in the pores during the deposition process, allowing more precise control over the finished membrane; and (iii) expensive vacuum components and cleanroom environment are eliminated. This opens up a new avenue for ceramic membrane development with nano-scale precision using ALD at atmospheric pressure.","atmospheric-pressure atomic layer deposition (AP-ALD); in-line gas permeation test; molecular weight cut-off; permporometry; pore narrowing; titanium dioxide (TiO); tubular ceramic membranes","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:ddff4858-806d-49cf-907c-0a14ce6b23ef","http://resolver.tudelft.nl/uuid:ddff4858-806d-49cf-907c-0a14ce6b23ef","Flow affects the structural and mechanical properties of the fibrin network in plasma clots","Eyisoylu, H. (TU Delft BN/Gijsje Koenderink Lab; Erasmus MC; Kavli institute of nanoscience Delft); Hazekamp, Emma D. (Erasmus MC); Cruts, Janneke (Erasmus MC); Koenderink, G.H. (TU Delft BN/Gijsje Koenderink Lab; Kavli institute of nanoscience Delft); de Maat, Moniek P.M. (Erasmus MC)","","2024","The fibrin network is one of the main components of thrombi. Altered fibrin network properties are known to influence the development and progression of thrombotic disorders, at least partly through effects on the mechanical stability of fibrin. Most studies investigating the role of fibrin in thrombus properties prepare clots under static conditions, missing the influence of blood flow which is present in vivo. In this study, plasma clots in the presence and absence of flow were prepared inside a Chandler loop. Recitrated plasma from healthy donors were spun at 0 and 30 RPM. The clot structure was characterized using scanning electron microscopy and confocal microscopy and correlated with the stiffness measured by unconfined compression testing. We quantified fibrin fiber density, pore size, and fiber thickness and bulk stiffness at low and high strain values. Clots formed under flow had thinner fibrin fibers, smaller pores, and a denser fibrin network with higher stiffness values compared to clots formed in absence of flow. Our findings indicate that fluid flow is an essential factor to consider when developing physiologically relevant in vitro thrombus models used in researching thrombectomy outcomes or risk of embolization. Graphical Abstract: [Figure not available: see fulltext.].","","en","journal article","","","","","","","","","","","BN/Gijsje Koenderink Lab","","",""
"uuid:be422b2d-28a0-4205-836b-231ff3d8c850","http://resolver.tudelft.nl/uuid:be422b2d-28a0-4205-836b-231ff3d8c850","A Parametric 3D Model of Human Airways for Particle Drug Delivery and Deposition","Geronzi, Leonardo (University of Rome Tor Vergata; RBF Morph, Rome); Fanni, Benigno Marco (Bioengineering Unit, Massa); De Jong, Bart (ONE Simulations, Leiden); Roest, G.T.H. (Grep IT, Noordwijkerhout); Kenjeres, S. (TU Delft ChemE/Transport Phenomena); Celi, Simona (Bioengineering Unit, Massa); Biancolini, Marco Evangelos (University of Rome Tor Vergata; RBF Morph, Rome)","","2024","The treatment for asthma and chronic obstructive pulmonary disease relies on forced inhalation of drug particles. Their distribution is essential for maximizing the outcomes. Patient-specific computational fluid dynamics (CFD) simulations can be used to optimize these therapies. In this regard, this study focuses on creating a parametric model of the human respiratory tract from which synthetic anatomies for particle deposition analysis through CFD simulation could be derived. A baseline geometry up to the fourth generation of bronchioles was extracted from a CT dataset. Radial basis function (RBF) mesh morphing acting on a dedicated tree structure was used to modify this baseline mesh, extracting 1000 synthetic anatomies. A total of 26 geometrical parameters affecting branch lengths, angles, and diameters were controlled. Morphed models underwent CFD simulations to analyze airflow and particle dynamics. Mesh morphing was crucial in generating high-quality computational grids, with 96% of the synthetic database being immediately suitable for accurate CFD simulations. Variations in wall shear stress, particle accretion rate, and turbulent kinetic energy across different anatomies highlighted the impact of the anatomical shape on drug delivery and deposition. The study successfully demonstrates the potential of tree-structure-based RBF mesh morphing in generating parametric airways for drug delivery studies.","computational fluid dynamics; parametric airways modeling; particle deposition; RBF mesh morphing; respiratory diseases","en","journal article","","","","","","","","","","","ChemE/Transport Phenomena","","",""
"uuid:0c3a8768-12d8-4f6a-a634-720ffe1573ee","http://resolver.tudelft.nl/uuid:0c3a8768-12d8-4f6a-a634-720ffe1573ee","Buckling of a monolayer of platelike particles trapped at a fluid-fluid interface","Prakash, Suriya (TU Delft Complex Fluid Processing); Perrin, H.R.L. (TU Delft Complex Fluid Processing); Botto, L. (TU Delft Complex Fluid Processing)","","2024","Particles trapped at a fluid-fluid interface by capillary forces can form a monolayer that jams and buckles when subject to uniaxial compression. Here we investigate experimentally the buckling mechanics of monolayers of millimeter-sized rigid plates trapped at a planar fluid-fluid interface subject to uniaxial compression in a Langmuir trough. We quantified the buckling wavelength and the associated force on the trough barriers as a function of the degree of compression. To explain the observed buckling wavelength and forces in the two-dimensional (2D) monolayer, we consider a simplified system composed of a linear chain of platelike particles. The chain system enables us to build a theoretical model which is then compared to the 2D monolayer data. Both the experiments and analytical model show that the wavelength of buckling of a monolayer of platelike particles is of the order of the particle size, a different scaling from the one usually reported for monolayers of spheres. A simple model of buckling surface pressure is also proposed, and an analysis of the effect of the bending rigidity resulting from a small overlap between nanosheet particles is presented. These results can be applied to the modeling of the interfacial rheology and buckling dynamics of interfacial layers of 2D nanomaterials.","","en","journal article","","","","","","","","","","","Complex Fluid Processing","","",""
"uuid:abb32843-ff56-44e2-b09f-94e141317fd0","http://resolver.tudelft.nl/uuid:abb32843-ff56-44e2-b09f-94e141317fd0","Supercurrent mediated by helical edge modes in bilayer graphene","Rout, P.K. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Papadopoulos, N. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Peñaranda, Fernando (Instituto de Ciencia de Materiales de Madrid (ICMM)); Watanabe, Kenji (National Institute for Materials Science); Taniguchi, Takashi (National Institute for Materials Science); Prada, Elsa (Instituto de Ciencia de Materiales de Madrid (ICMM)); San-Jose, Pablo (Instituto de Ciencia de Materiales de Madrid (ICMM)); Goswami, S. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2024","Bilayer graphene encapsulated in tungsten diselenide can host a weak topological phase with pairs of helical edge states. The electrical tunability of this phase makes it an ideal platform to investigate unique topological effects at zero magnetic field, such as topological superconductivity. Here we couple the helical edges of such a heterostructure to a superconductor. The inversion of the bulk gap accompanied by helical states near zero displacement field leads to the suppression of the critical current in a Josephson geometry. Using superconducting quantum interferometry we observe an even-odd effect in the Fraunhofer interference pattern within the inverted gap phase. We show theoretically that this effect is a direct consequence of the emergence of helical modes that connect the two edges of the sample. The absence of such an effect at high displacement field, as well as in bare bilayer graphene junctions, supports this interpretation and demonstrates the topological nature of the inverted gap.","","en","journal article","","","","","","","","","","","QRD/Goswami Lab","","",""
"uuid:0a43717f-695d-48d6-a7df-d70939d027f6","http://resolver.tudelft.nl/uuid:0a43717f-695d-48d6-a7df-d70939d027f6","Evaluation of Horizontal and Vertical Constrained Rod Casting Mold on Hot Tearing Susceptibility of Al-Cu Alloys","Rajagukguk, Kardo (Universitas Gadjah Mada; Institut Teknologi Sumatera (ITERA)); Suyitno, Suyitno (Universitas Gadjah Mada; Universitas Tidar (UNTIDAR)); Saptoadi, Harwin (Universitas Gadjah Mada); Kusumaningtyas, Indraswari (Universitas Gadjah Mada); Arifvianto, Budi (Universitas Gadjah Mada); Salim, Urip Agus (Universitas Gadjah Mada); Mahardika, Muslim (Universitas Gadjah Mada); Pujiyulianto, Eko (Universitas Gadjah Mada; Institut Teknologi Sumatera (ITERA)); Katgerman, L. (TU Delft Team Joris Dik; Katgerman Aluminium Technology)","","2024","This research aims to evaluate horizontal and vertical constrained rod casting (CRC) molds on hot tearing susceptibility (HTS) of Al-xCu casting alloys with 2.2, 3.6, 7.5, and 12.5 percent Cu. The hot tears on the casting product were observed using a macroscopic approach. In addition, the hot tearing susceptibility of each casting product prepared using these molds was evaluated using the HTS formula. The results show that the vertical CRC mold has a higher HTS value than the horizontal CRC mold. The rod length is a significant factor in causing hot tearing. Longer rods are more susceptible to hot tearing. The horizontal CRC mold provides a clearer effect of rod length and Cu composition on the average HTS value. In the vertical CRC mold, the effect of Cu composition on the average HTS value is less clear. Therefore, it is highly recommended to use horizontal CRC mold for HTS testing of aluminum casting alloys.","Al-Cu alloys; casting; constrained rod casting (CRC); horizontal CRC mold; hot tearing susceptibility; vertical CRC mold","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-29","","","Team Joris Dik","","",""
"uuid:d02f2f4e-e23b-433a-8901-026ea803459f","http://resolver.tudelft.nl/uuid:d02f2f4e-e23b-433a-8901-026ea803459f","Multi-trait analysis characterizes the genetics of thyroid function and identifies causal associations with clinical implications","Sterenborg, Rosalie B.T.M. (Radboud University Medical Center; Erasmus MC); Steinbrenner, Inga (University Medical Center Freiburg); Li, Yong (Institute of Genetic Epidemiology; University Medical Center Freiburg); Bujnis, Melissa N. (University of Utah); Naito, Tatsuhiko (Osaka University Graduate School of Medicine; RIKEN Center for Integrative Medical Sciences); Marouli, Eirini (Barts and The London School of Medicine and Dentistry; Queen Mary University of London); Meima, M.E. (Erasmus MC); van den Akker, E.B. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center); Teumer, Alexander (University Medicine Greifswald; Bialystok University of Technology); Medici, M. (Radboud University Medical Center; Erasmus MC)","","2024","To date only a fraction of the genetic footprint of thyroid function has been clarified. We report a genome-wide association study meta-analysis of thyroid function in up to 271,040 individuals of European ancestry, including reference range thyrotropin (TSH), free thyroxine (FT4), free and total triiodothyronine (T3), proxies for metabolism (T3/FT4 ratio) as well as dichotomized high and low TSH levels. We revealed 259 independent significant associations for TSH (61% novel), 85 for FT4 (67% novel), and 62 novel signals for the T3 related traits. The loci explained 14.1%, 6.0%, 9.5% and 1.1% of the total variation in TSH, FT4, total T3 and free T3 concentrations, respectively. Genetic correlations indicate that TSH associated loci reflect the thyroid function determined by free T3, whereas the FT4 associations represent the thyroid hormone metabolism. Polygenic risk score and Mendelian randomization analyses showed the effects of genetically determined variation in thyroid function on various clinical outcomes, including cardiovascular risk factors and diseases, autoimmune diseases, and cancer. In conclusion, our results improve the understanding of thyroid hormone physiology and highlight the pleiotropic effects of thyroid function on various diseases.","","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:1ce2fa75-5521-436c-b311-ff402a48ab1f","http://resolver.tudelft.nl/uuid:1ce2fa75-5521-436c-b311-ff402a48ab1f","Aggregating value systems for decision support","Lera-Leri, Roger X. (Artificial Intelligence Research Institute, Spanish National Scientific Research Council); Liscio, E. (TU Delft Interactive Intelligence); Bistaffa, Filippo (Artificial Intelligence Research Institute, Spanish National Scientific Research Council); Jonker, C.M. (TU Delft Interactive Intelligence); Lopez-Sanchez, Maite (Universitat Politecnica de Catalunya); Murukannaiah, P.K. (TU Delft Interactive Intelligence); Rodriguez-Aguilar, Juan A. (Artificial Intelligence Research Institute, Spanish National Scientific Research Council); Salas-Molina, Francisco (Universitat Politécnica de Valencia)","","2024","We adopt an emerging and prominent vision of human-centred Artificial Intelligence that requires building trustworthy intelligent systems. Such systems should be capable of dealing with the challenges of an interconnected, globalised world by handling plurality and by abiding by human values. Within this vision, pluralistic value alignment is a core problem for AI– that is, the challenge of creating AI systems that align with a set of diverse individual value systems. So far, most literature on value alignment has considered alignment to a single value system. To address this research gap, we propose a novel method for estimating and aggregating multiple individual value systems. We rely on recent results in the social choice literature and formalise the value system aggregation problem as an optimisation problem. We then cast this problem as an ℓp-regression problem. Doing so provides a principled and general theoretical framework to model and solve the aggregation problem. Our aggregation method allows us to consider a range of ethical principles, from utilitarian (maximum utility) to egalitarian (maximum fairness). We illustrate the aggregation of value systems by considering real-world data from two case studies: the Participatory Value Evaluation process and the European Values Study. Our experimental evaluation shows how different consensus value systems can be obtained depending on the ethical principle of choice, leading to practical insights for a decision-maker on how to perform value system aggregation.","AI & ethics; Optimisation; Value systems","en","journal article","","","","","","","","","","","Interactive Intelligence","","",""
"uuid:a3bdb09c-7573-4ede-88b6-cf84583ca9f5","http://resolver.tudelft.nl/uuid:a3bdb09c-7573-4ede-88b6-cf84583ca9f5","Impact of large-scale hydrogen electrification and retrofitting of natural gas infrastructure on the European power system","Morales-Espana, G. (TU Delft Algorithmics; TNO Energy & Materials Transition); Hernández-Serna, Ricardo (Eurus Energy Europe BV); Tejada-Arango, Diego A. (TNO Energy & Materials Transition; Comillas Pontifical University); Weeda, Marcel (TNO Energy & Materials Transition)","","2024","In this paper, we aim to analyse the impact of hydrogen production decarbonisation and electrification scenarios on the infrastructure development, generation mix, CO2 emissions, and system costs of the European power system, considering the retrofit of the natural gas infrastructure. We define a reference scenario for the European power system in 2050 and use scenario variants to obtain additional insights by breaking down the effects of different assumptions. The scenarios were analysed using the European electricity market model COMPETES, including a proposed formulation to consider retrofitting existing natural gas networks to transport hydrogen instead of methane. According to the results, 60% of the EU's hydrogen demand is electrified, and approximately 30% of the total electricity demand will be to cover that hydrogen demand. The primary source of this electricity would be non-polluting technologies. Moreover, hydrogen flexibility significantly increases variable renewable energy investment and production, and reduces CO2 emissions. In contrast, relying on only electricity transmission increases costs and CO2 emissions, emphasising the importance of investing in an H2 network through retrofitting or new pipelines. In conclusion, this paper shows that electrifying hydrogen is necessary and cost-effective to achieve the EU's objective of reducing long-term emissions.","Electrification; Hydrogen; Retrofit; Steam methane reforming","en","journal article","","","","","","","","","","","Algorithmics","","",""
"uuid:63aa2011-308e-4622-bb07-5fd32b076044","http://resolver.tudelft.nl/uuid:63aa2011-308e-4622-bb07-5fd32b076044","Milliarcsecond-scale radio structure of the most distant BL Lac object candidate at redshift 6.57","Frey, S. (Institute of Physics and Astronomy; Eötvös University; MTA Centre of Excellence); Zhang, Y. (Chinese Academy of Sciences; Key Laboratory of Radio Astronomy); Perger, K. (Konkoly Observatory Hungarian Academy of Sciences; MTA Centre of Excellence); An, T. (Chinese Academy of Sciences; Key Laboratory of Radio Astronomy); Gabányi, K. (Konkoly Observatory Hungarian Academy of Sciences; MTA Centre of Excellence; Eötvös University); Gurvits, L. (TU Delft Astrodynamics & Space Missions; Joint Institute for VLBI ERIC); Hwang, C. Y. (National Central University Taiwan); Koptelova, E. (National Central University Taiwan); Paragi, Z. (Joint Institute for VLBI ERIC); Fogasy, J. (Konkoly Observatory Hungarian Academy of Sciences; MTA Centre of Excellence)","","2024","Context. The existence of accreting supermassive black holes of up to billions of solar masses at early cosmological epochs (in the context of this work, redshifts z & 6) requires very fast growth rates that are challenging to explain. The presence of a relativistic jet can be a direct indication of activity and accretion status in active galactic nuclei (AGN), constraining the radiative properties of these extreme objects. However, known jetted AGN beyond z ∼ 6 are still very rare. Aims. The radio-emitting AGN J2331+1129 has recently been claimed as a candidate BL Lac object at redshift z = 6.57 based on its synchrotron-dominated emission spectrum and a lack of ultraviolet or optical emission lines. It is a promising candidate for the highest-redshift blazar known to date. The aim of the observations described here is to support or refute the blazar classification of this peculiar source. Methods. We performed high-resolution radio interferometric imaging observations of J2331+1129 using the Very Long Baseline Array at 1.6 and 4.9 GHz in February 2022. Results. The images reveal a compact but slightly resolved, flat-spectrum core feature at both frequencies, indicating that the total radio emission is produced by a compact jet and originates from within a central region of ∼10 pc in diameter. While these details are consistent with the radio properties of a BL Lac object, the inferred brightness temperatures are at least an order of magnitude lower than expected for a Doppler-boosted radio jet, which casts doubt on the high-redshift BL Lac identification.","BL Lacertae objects: individual: J2331+1129; galaxies: high-redshift; radio continuum: galaxies; techniques: interferometric","en","journal article","","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:08b2d677-4383-40af-b49d-3b1b8e31031b","http://resolver.tudelft.nl/uuid:08b2d677-4383-40af-b49d-3b1b8e31031b","Towards a digital twin architecture for the lighting industry","Guerra, Victor (Pi Lighting Sarl); Hamon, Benoit (Pi Lighting Sarl); Bataillou, Benoit (Pi Lighting Sarl); Inamdar, A.S. (TU Delft Electronic Components, Technology and Materials); van Driel, W.D. (TU Delft Electronic Components, Technology and Materials; Signify)","","2024","This paper introduces an ontology-based Digital Twin (DT) architecture for the lighting industry, integrating simulation models, data analytics, and visualization to represent luminaires. The ontology standardizes luminaire components, facilitating interoperability with design tools. The calculated ontology-level metrics suggest mid-level complexity with Size Of Vocabulary (SOV) at 37, Edge-to-Node Ratio (ENR) at 0.865, Tree Impurity (TIP) at 0, and Entropy Of Graph (EOG) at 2.61. A use case explores the utility of the ontology in the design phase across two different geographical locations, assessing environmental adaptability. The ontology captures opto-thermo-electric interactions, providing insights into luminaire performance. Results from inflating the DT and conducting simulations align with existing literature, indicating a degradation of around 12% over 8 years on the radiant flux. This ontology, up to the authors’ knowledge, is the first formal definition for the lighting industry, aiming to encompass the entire luminaire lifecycle. The current focus is on design and operational phases, with potential future enhancements to include real-time monitoring for performance evaluation and predictive maintenance. This work contributes to luminaire analysis and supports the development of sustainable lighting solutions in the industry.","Digital twin; Lighting; Ontology; Predictive maintenance; Remaining useful lifetime; Scheduled maintenance","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-06","","","Electronic Components, Technology and Materials","","",""
"uuid:0275192e-7b31-4d8e-901e-52141b5ea61b","http://resolver.tudelft.nl/uuid:0275192e-7b31-4d8e-901e-52141b5ea61b","District heating with complexity: Anticipating unintended consequences in the transition towards a climate-neutral city in the Netherlands","Gürsan, C. (Nijmegen School of Management); de Gooyert, V. (Nijmegen School of Management); de Bruijne, M.L.C. (TU Delft Organisation & Governance); Raaijmakers, J. (Nijmegen School of Management)","","2024","District heating systems are considered a feasible heating alternative to replace natural gas to mitigate emissions in cities. However, urban transitions are very complex because energy systems often operate in densely populated areas, which gives rise to all kinds of interdependencies in cities. These interdependencies can result in unintended consequences which can indirectly help or hinder urban energy transitions. Understanding these influences the transition to climate neutrality. This research investigates the lessons learned from a project conducted in Rotterdam: a high-density city in the Netherlands which is expanding its district heating systems. We use qualitative system dynamics models to explore the underlying complexity and to recognize indirect consequences of policies. Our results cover both technologically oriented and policy-oriented insights, contributing to the literature on transition governance in cities. On the one hand, the national and urban strategies in the Netherlands activate mechanisms that support cities with district heating systems such as Rotterdam. On the other hand, the same strategies could also lead to a potential rivalry between energy efficiency and energy security, which are both crucial goals in urban transition governance. Participative modeling provides policy-makers with an analytical tool to detect systemic dependencies which can be used to identify synergies and barriers among different energy policy objectives. This helps avoiding potential unintended consequences including the use of carbon-heavy systems and displacing investments from energy efficiency and renewable heating systems.","District heating; Energy transition; Feedback effects; Infrastructure interdependencies; Socio-technical systems; System dynamics","en","journal article","","","","","","","","","","","Organisation & Governance","","",""
"uuid:abc3d88e-843f-4bf5-a6a6-4015be0a8f4e","http://resolver.tudelft.nl/uuid:abc3d88e-843f-4bf5-a6a6-4015be0a8f4e","Gate-tunable kinetic inductance parametric amplifier","Splitthoff, L.J. (TU Delft QRD/Kouwenhoven Lab; TU Delft Communication QuTech; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wesdorp, J.J. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Pita-Vidal, Marta (TU Delft QRD/Kouwenhoven Lab; TU Delft Communication QuTech; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bargerbos, A. (TU Delft QRD/Kouwenhoven Lab; TU Delft Communication QuTech; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Liu, Yu (University of Copenhagen); Andersen, C.K. (TU Delft Andersen Lab; TU Delft Communication QuTech; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2024","Superconducting parametric amplifiers play a crucial role in the preparation and readout of quantum states at microwave frequencies, enabling high-fidelity measurements of superconducting qubits. Most existing implementations of these amplifiers rely on the nonlinearity from Josephson junctions, superconducting quantum interference devices, or disordered superconductors. Additionally, frequency tunability arises typically from either flux or current biasing. In contrast, semiconductor-based parametric amplifiers are tunable by local electric fields, which impose a smaller thermal load on the cryogenic setup than current and flux biasing and lead to vanishing crosstalk to other on-chip quantum systems. In this work, we present a gate-tunable parametric amplifier that operates without Josephson junctions, using a proximitized semiconducting nanowire. This design achieves near-quantum-limited performance, featuring more than 20-dB gain and a 30-MHz gain-bandwidth product. The absence of Josephson junctions results in advantages, including substantial saturation powers of -120 dBm, magnetic field compatibility up to 500mT, and frequency tunability over a range of 15 MHz. Our realization of a parametric amplifier supplements efforts towards gate-controlled superconducting electronics, further advancing the abilities for high-performing quantum measurements of semiconductor-based and superconducting quantum devices.","","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:ca88f894-fa33-4e0f-80ac-4de4f6988c3c","http://resolver.tudelft.nl/uuid:ca88f894-fa33-4e0f-80ac-4de4f6988c3c","Public acceptance in direct potable water reuse: a call for incorporating responsible research and innovation","Moesker, K. (TU Delft Values Technology and Innovation); Pesch, U. (TU Delft Values Technology and Innovation); Doorn, N. (TU Delft Values Technology and Innovation)","","2024","As global issues such as climate change and diminishing resources become increasingly pressing, water recycling has moved into the focus. However, the successful implementation of Direct Potable Water Reuse (DPR) projects hinges on securing public acceptance, which remains challenging. This paper aims to flesh out possible reasons for the lingering public rejection of DPR. We will do so by conducting a literature review on how public acceptance is understood and what approaches are proposed to enhance it. These approaches are analyzed using Responsible Research and Innovation principles and the `opening up', `closing down' and `leaving ajar' approaches. Our research identifies an overreliance on the controversial information deficit model, closing down large parts of public engagement. We advocate for becoming more inclusive through the `leaving ajar' approach. Particularly, attention should be paid to reflexivity and responsiveness to public concerns to ensure meaningful public engagement.","Direct potable reuse; information deficit model; public acceptance; public participation; responsible research and innovation","en","journal article","","","","","","","","","","Values Technology and Innovation","","","",""
"uuid:01b7743d-7174-434c-a47e-ee2e705875a7","http://resolver.tudelft.nl/uuid:01b7743d-7174-434c-a47e-ee2e705875a7","Bioethanol separation by a new pass-through distillation process","Jankovic, T.J. (TU Delft BT/Bioprocess Engineering); Straathof, Adrie J.J. (TU Delft BT/Bioprocess Engineering); McGregor, Ian R. (Drystill Holdings, Mississauga); Kiss, A.A. (TU Delft ChemE/Product and Process Engineering)","","2024","Distillation is the most used separation technology at industrial-scale, but using distillation in bio-based processes (e.g. fermentation processes to produce bioethanol) is quite challenging when mild temperatures are needed to keep the microbes alive. Vacuum distillation can be used to perform evaporation at low temperatures, but setting a low distillation pressure fixes also the condensation temperature to very low values that may require expensive refrigeration. Pass-through distillation (PTD) is an emerging hybrid separation technology that effectively combines distillation with absorption in a sorption-assisted distillation process that decouples the evaporation and condensation steps. This is achieved by inserting between the evaporation and condensation steps an absorption-desorption loop that passes through the component to be separated and allows the use of different pressures and types of heating and cooling utilities. This paper is the first to present the process design and rigorous simulation (implemented in Aspen Plus) of a new pass-through distillation process for bioethanol (∼100 ktonne/y plant capacity), proving its effectiveness in concurrent alcohol recovery and fermentation (CARAF). Combining PTD with heat pumps leads to low recovery costs of 0.122 $/kgEtOH and energy requirements of only 1.723 kWthh/kgEtOH. Alternatively, combining PTD with multi-effect distillation resulted in 0.131 $/kgEtOH recovery costs and 1.834 kWthh/kgEtOH energy intensity.","Bioethanol; Distillation; Fluid separation; Industrial fermentation; Process design","en","journal article","","","","","","","","","","","BT/Bioprocess Engineering","","",""
"uuid:f056ed8a-3839-4a22-86fe-78ecaa90a9c7","http://resolver.tudelft.nl/uuid:f056ed8a-3839-4a22-86fe-78ecaa90a9c7","Social Meritocracy and Unjust Social Hierarchies: Three Proposals to Limit Meritocracy’s Erosion of Social Cooperation","Ziliotti, E. (TU Delft Ethics & Philosophy of Technology)","","2024","A well-functioned society depends on its ability to nurture, attract, and deploy talents in critical sectors. However, the implementation of some meritocratic principles to allocate positions often leads to unjust social hierarchies. Is there, then, a solution to meritocracy’s dysfunctional hierarchical effects? This paper attempts to answer this by drawing on the real-world cases of Singapore and the USA to investigate the relationship of toxic social hierarchies with meritocracy. It proposes three solutions to curb the unjustifiable social stratifications and the erosion of social cooperation often associated with social meritocracy. These reflections could help to shed light on the grounds for the ongoing debates on social hierarchies and provide valuable insights into how to weigh up existing socio-political structures.","Equality of opportunity; Singapore; Social meritocracy; The Tyranny of Merit; Toxic social hierarchies","en","journal article","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:2445fbb2-3cf8-4b57-8855-60f54cd14b53","http://resolver.tudelft.nl/uuid:2445fbb2-3cf8-4b57-8855-60f54cd14b53","Ethics of generative AI and manipulation: a design-oriented research agenda","Klenk, M.B.O.T. (TU Delft Ethics & Philosophy of Technology)","","2024","Generative AI enables automated, effective manipulation at scale. Despite the growing general ethical discussion around generative AI, the specific manipulation risks remain inadequately investigated. This article outlines essential inquiries encompassing conceptual, empirical, and design dimensions of manipulation, pivotal for comprehending and curbing manipulation risks. By highlighting these questions, the article underscores the necessity of an appropriate conceptualisation of manipulation to ensure the responsible development of Generative AI technologies.","AI ethics; Deception; Generative AI; Large Language Models (LLMs); Manipulation; Persuasion; Value sensitive design","en","journal article","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:149382c4-eb4a-449b-8927-c252803ada9f","http://resolver.tudelft.nl/uuid:149382c4-eb4a-449b-8927-c252803ada9f","Understanding preferences for mobility-on-demand services through a context-aware survey and non-compensatory strategy","Dubey, S.K. (TU Delft Transport and Planning); Cats, O. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning)","","2024","The potential lack of realism in stated-preference surveys is particularly acute in contexts where disaggregate real-world data is challenging to obtain. Mobility-on-Demand (MOD) services present one such context. The MOD context is unique due to factors such as service reliability (difference in stated vs. actual travel and waiting time) and current mode inertia which affect the choice of MOD services and are difficult to infer from revealed preference data. Further, travel mode choices are repetitive and constitute a relatively easy choice situation. Consequently, individuals may utilize simple non-compensatory strategies. In this study, we design a survey to mimic real-world choice sets using a joint revealed and stated- (RP-SP) preference survey approach. We construct the complete journey of individuals taking into account departure time, access and egress mode, current primary mode and origin–destination pair. A Choquet Integral (CI)-based choice model with endogeneity correction is employed, thereby allowing to approximate non-compensatory behaviour. Results confirm the presence of non-compensatory behaviour across all mode users (car, public transport and bike). Reliability and inertia effects are most pronounced for car users including the potential for a combined departure time-mode shift towards MOD. Owing to non-compensatory behaviour and inertia, higher travel costs cannot be fully compensated by shorter waiting and travel times and a differential pricing strategy may be required to increase MOD market share. Failure to account for common unobserved factors between the RP and SP choices results in inflated attribute importance.","Choquet integral; Differential pricing; Endogeneity; Non-compensatory behavior; Service reliability","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:314cd985-d043-4869-b008-8bb76e8b1953","http://resolver.tudelft.nl/uuid:314cd985-d043-4869-b008-8bb76e8b1953","Maximizing wind farm power output with the helix approach: Experimental validation and wake analysis using tomographic particle image velocimetry","van der Hoek, D.C. (TU Delft Team Jan-Willem van Wingerden); Van den Abbeele, B.H.L. (TU Delft Team Jan-Willem van Wingerden); Ferreira, Carlos (TU Delft Wind Energy); van Wingerden, J.W. (TU Delft Team Jan-Willem van Wingerden)","","2024","Wind farm control can play a key role in reducing the negative impact of wakes on wind turbine power production. The helix approach is a recent innovation in the field of wind farm control, which employs individual blade pitch control to induce a helical velocity profile in a wind turbine wake. This forced meandering of the wake has turned out to be very effective for the recovery of the wake, increasing the power output of downstream turbines by a significant amount. This paper presents a wind tunnel study with two scaled wind turbine models of which the upstream turbine is operated with the helix approach. We used tomographic particle image velocimetry to study the dynamic behavior of the wake under the influence of the helix excitation. The measured flow fields confirm the wake recovery capabilities of the helix approach compared with normal operation. Additional emphasis is put on the effect of the helix approach on the breakdown of blade tip vortices, a process that plays an important role in re-energizing the wake. Measurements indicate that the breakdown of tip vortices and the resulting destabilization of the wake are enhanced significantly with the helix approach. Finally, turbine measurements show that the helix approach was able to increase the combined power for this particular two-turbine setup by as much as 15%.","dynamic individual pitch control; experimental validation; the helix approach; tomographic piv; wind farm control; wind farm power maximization","en","journal article","","","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:c0a5ffcc-8ce4-48d4-b47f-fc2c84ca89a8","http://resolver.tudelft.nl/uuid:c0a5ffcc-8ce4-48d4-b47f-fc2c84ca89a8","Microporous Sulfur–Carbon Materials with Extended Sodium Storage Window","Eren, Enis Oğuzhan (Max-Planck-Inst. F. Kolloid-und G.); Esen, Cansu (Max-Planck-Inst. F. Kolloid-und G.); Scoppola, Ernesto (Max-Planck-Inst. F. Kolloid-und G.); Song, Zihan (Max-Planck-Inst. F. Kolloid-und G.); Senokos, Evgeny (Max-Planck-Inst. F. Kolloid-und G.); Zschiesche, Hannes (Max-Planck-Inst. F. Kolloid-und G.); Cruz, Daniel (Fritz-Haber-Institut der Max-Planck-Gesellschaft; Max-Planck-Institut für Chemische Engergiekonversion); Lauermann, Iver (Helmholtz-Zentrum Berlin für Materialen und Energie GmbH); Kumru, B. (TU Delft Group Kumru)","","2024","Developing high-performance carbonaceous anode materials for sodium-ion batteries (SIBs) is still a grand quest for a more sustainable future of energy storage. Introducing sulfur within a carbon framework is one of the most promising attempts toward the development of highly efficient anode materials. Herein, a microporous sulfur-rich carbon anode obtained from a liquid sulfur-containing oligomer is introduced. The sodium storage mechanism shifts from surface-controlled to diffusion-controlled at higher synthesis temperatures. The different storage mechanisms and electrode performances are found to be independent of the bare electrode material's interplanar spacing. Therefore, these differences are attributed to an increased microporosity and a thiophene-rich chemical environment. The combination of these properties enables extending the plateau region to higher potential and achieving reversible overpotential sodium storage. Moreover, in-operando small-angle X-ray scattering (SAXS) reveals reversible electron density variations within the pore structure, in good agreement with the pore-filling sodium storage mechanism occurring in hard carbons (HCs). Eventually, the depicted framework will enable the design of high-performance anode materials for sodium-ion batteries with competitive energy density.","anode; carbon; in-operando SAXS; sodium-ion battery; sulfur","en","journal article","","","","","","","","","","","Group Kumru","","",""
"uuid:0dcdccf4-485b-4b2a-b314-fa2876be2884","http://resolver.tudelft.nl/uuid:0dcdccf4-485b-4b2a-b314-fa2876be2884","Saturated transverse permeability of unidirectional rovings for pultrusion: The effect of microstructural evolution through compaction","Yuksel, O. (TU Delft Group Çaglar; University of Twente); Caglar, Baris (TU Delft Aerospace Manufacturing Technologies); Broggi, G.C. (TU Delft Group Çaglar; EPFL Switzerland); Michaud, Véronique (EPFL Switzerland); Akkerman, Remko (University of Twente); Baran, Ismet (University of Twente)","","2024","The transverse permeability of roving/tow-based fiber reinforcement is of great importance for accurate flow modeling in the pultrusion process. This study proposes an experimental approach to characterize the roving-based fiber beds' permeability under different compaction conditions. The experimental permeability results of thick roving-based preforms were reported and compared with the permeability values of roving-based preforms in the literature. A representative preform was infused under vacuum conditions. Its thickness was varied to replicate the different compaction values observed in permeability tests. Micrographs were then collected from it and analyzed to highlight the microscale transformations caused by processing/compaction on the fiber arrangement. The analysis revealed that compaction resulted in the reorganization of filaments along the direction of the applied compaction. Overall, the uniformity of the spatial filament distribution, i.e., the homogeneity within the fibrous domain, increased with increasing compaction. Furthermore, the microstructural analysis demonstrated transverse anisotropy within the tested domains, indicating that the obtained permeability results represented an upper boundary. In addition to the experimental analyses, various transverse permeability models, which were developed based on recently introduced statistical descriptors of fiber distribution, were evaluated by using the statistical descriptors extracted from the analyzed cross-sections. Among these models, the one correlating the second neighbor fiber distance with apparent permeability exhibited good agreement with the experimental results. Highlights: Transverse permeability measurement of a roving-based reinforcement was presented. The influence of compaction on the microstructure was investigated at the filament level. Filament distribution in a pultruded profile was analyzed by using statistical descriptors. The results of the experiments and the models in the literature were compared. The correlation between microstructural features and apparent permeability was discussed.","microstructural analysis; permeability; pultrusion; vacuum infusion","en","journal article","","","","","","","","","","","Group Çaglar","","",""
"uuid:3c648d3e-970d-4da3-919c-284229175e1d","http://resolver.tudelft.nl/uuid:3c648d3e-970d-4da3-919c-284229175e1d","Effects of pellet-sinter interaction parameters on component segregation and bed porosity considering flow velocity and mixture composition: A DEM study","Roeplal, R.N. (TU Delft Transport Engineering and Logistics); Pang, Y. (TU Delft Transport Engineering and Logistics); Schott, D.L. (TU Delft Transport Engineering and Logistics)","","2024","Bed permeability is a crucial factor in blast furnace performance which depends on the material distribution achieved through charging. Since a homogeneous bed of pellet and sinter is recommended, it is crucial to understand whether segregation of the pellet-sinter mixture occurs during charging. The Discrete Element Method is useful in this regard; however, simulations of pellet-sinter mixture charging currently lack credibility since pellet-sinter interaction parameters have not yet been calibrated and validated. Determining pellet-sinter interaction parameters will require significant efforts, so it is useful to know whether mixture segregation and the resulting bed permeability are sensitive to these parameters. In this work, we investigate to what extent the restitution coefficient, sliding friction coefficient and rolling friction coefficient between pellet and sinter affect segregation during bed formation and the resulting permeability in terms of porosity using a simplified charging setup. The investigation is done for different mixture compositions and flow velocities, and analysis settings including sample size and sampling directions. We conclude that all parameters affect segregation and porosity, regardless of the composition and velocity. Hence, all mixture parameters including the interaction parameters between the components must be carefully calibrated when developing a model for predicting permeability.","Blast furnace mixture; Component segregation; DEM; Interaction parameters; Porosity; Sensitivity analysis","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:ffac03f6-013d-42c5-afef-f752bd282a79","http://resolver.tudelft.nl/uuid:ffac03f6-013d-42c5-afef-f752bd282a79","Macrolitter budget and spatial distribution in a groyne field along the Waal river","Grosfeld, J. J. (Student TU Delft); Schoor, M. M. (Rijkswaterstaat); Taormina, R. (TU Delft Sanitary Engineering); Luxemburg, W.M.J. (TU Delft Water Resources); Collas, F. P.L. (Radboud Universiteit Nijmegen; Rijkswaterstaat)","","2024","Current research on riverine macrolitter does not yet provide a theoretic framework on the dynamics behind its accumulation and distribution along riverbanks. In an attempt to better understand these dynamics a detailed field survey of three months was conducted in which location of macrolitter items within a single groyne field along the Waal riverbanks was tracked. The data provided insight into the daily changing patterns of spatial item distribution with respect to the waterline. Furthermore, the rates of item uptake and deposition were monitored and related to hydrologic fluctuations. Uptake was initiated by rising water levels and was generally higher when the water level increased faster. Deposition occurred continuously, despite hydrologic fluctuations. This caused the riverbank macrolitter budget to be positive during stable or dropping water levels and negative during rising water levels. Although the results show clear patterns an extended monitoring duration is required to fully understand the fate of plastic objects.","Accumulation; Freshwater; Macroplastic; Monitoring; Pollution; Riverbanks","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:cdf52273-fdc5-40f5-8d8d-6b6c0394c2fc","http://resolver.tudelft.nl/uuid:cdf52273-fdc5-40f5-8d8d-6b6c0394c2fc","Design and evaluation of a smart passive dynamic arm support for robotic-assisted laparoscopic surgery","Schrijvershof, Pim (Student TU Delft); Rahimi, A. Masie (Amsterdam UMC; Cancer Center Amsterdam; Amsterdam Skills Centre for Health Sciences); Leone, Nicola (University of Turin); Bloemendaal, Alexander (Reinier de Graaf Gasthuis); Daams, Freek (Amsterdam UMC; Cancer Center Amsterdam; Amsterdam Skills Centre for Health Sciences); Arezzo, Alberto (University of Turin); Mintz, Yoav (Hadassah-Hebrew University Medical Center); Horeman, T. (TU Delft Medical Instruments & Bio-Inspired Technology)","","2024","Surgeons performing robotic-assisted laparoscopic surgery experience physical stress and overuse of shoulder muscles due to sub-optimal arm support during surgery. The objective is to present a novel design and prototype of a dynamic arm support for robotic laparoscopic surgery to evaluate its ergonomics and performance on the AdLap-VR simulation training device. The prototype was designed using the mechanical engineering design process: Technical requirements, concept creation, concept selection, 3D-design and built of the prototype. A crossover study was performed on a marble sorting task on the AdLap-VR. The first group performed four trials without the arm support, followed by four trials with the arm support, and the other group executed the sequence vice versa. The performance parameters used were time to complete (s), path length (mm), and the number of collisions. Afterward, the participants filled out a questionnaire on the ergonomic experience regarding both situations. 20 students executed 160 performed trials on the AdLap-VR Significant decreases in the subjective comfort parameters mental demand, physical demand, effort and frustration were observed as a result of introducing the novel arm support. Significant decreases in the objective performance parameters path length and the number of collisions were also observed during the tests. The newly developed dynamic arm support was found to improve comfort and enhance performance through increased stability on the robotic surgery skills simulator AdLap-VR.","Arm support; Ergonomics; Fatigue; Laparoscopy; RAS; Robotic surgery","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:417b29e8-4273-4778-a2c4-8ed733c45ef1","http://resolver.tudelft.nl/uuid:417b29e8-4273-4778-a2c4-8ed733c45ef1","Landau quantization near generalized Van Hove singularities: Magnetic breakdown and orbit networks","Zakharov, V. A. (Universiteit Leiden); Bozkurt, A.M. (TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Akhmerov, A.R. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft); Oriekhov, D. (Universiteit Leiden)","","2024","We develop a theory of magnetic breakdown (MB) near high-order saddle points in the dispersions of two-dimensional materials, where two or more semiclassical cyclotron orbits approach each other. MB occurs due to quantum tunneling between several trajectories, which leads to nontrivial scattering amplitudes and phases. We show that for any saddle point this problem can be solved by mapping it to a scattering problem in a 1D tight-binding chain. Moreover, the occurrence of magnetic breakdown on the edges of the Brillouin zone facilitates the delocalization of the bulk Landau level states and the formation of 2D orbit networks. These extended network states compose dispersive mini bands with finite energy broadening. This effect can be observed in transport experiments as a strong enhancement of the longitudinal bulk conductance in a quantum Hall bar. In addition, it may be probed in STM experiments by visualizing bulk current patterns.","","en","journal article","","","","","","","","","","","QRD/Wimmer Group","","",""
"uuid:087073a1-0685-434b-ba33-ac7d93d294a1","http://resolver.tudelft.nl/uuid:087073a1-0685-434b-ba33-ac7d93d294a1","What is an app store? The software engineering perspective","Zhu, Wenhan (David R. Cheriton School of Computer Science); Proksch, S. (TU Delft Software Engineering); German, Daniel M. (University of Victoria); Godfrey, Michael W. (David R. Cheriton School of Computer Science); Li, Li (Beihang University); McIntosh, Shane (David R. Cheriton School of Computer Science)","","2024","“App stores” are online software stores where end users may browse, purchase, download, and install software applications. By far, the best known app stores are associated with mobile platforms, such as Google Play for Android and Apple’s App Store for iOS. The ubiquity of smartphones has led to mobile app stores becoming a touchstone experience of modern living. App stores have been the subject of many empirical studies. However, most of this research has concentrated on properties of the apps rather than the stores themselves. Today, there is a rich diversity of app stores and these stores have largely been overlooked by researchers: app stores exist on many distinctive platforms, are aimed at different classes of users, and have different end-goals beyond simply selling a standalone app to a smartphone user. The goal of this paper is to survey and characterize the broader dimensionality of app stores, and to explore how and why they influence software development practices, such as system design and release management. We begin by collecting a set of app store examples from web search queries. By analyzing and curating the results, we derive a set of features common to app stores. We then build a dimensional model of app stores based on these features, and we fit each app store from our web search result set into this model. Next, we performed unsupervised clustering to the app stores to find their natural groupings. Our results suggest that app stores have become an essential stakeholder in modern software development. They control the distribution channel to end users and ensure that the applications are of suitable quality; in turn, this leads to developers adhering to various store guidelines when creating their applications. However, we found the app stores operational model could vary widely between stores, and this variability could in turn affect the generalizability of existing understanding of app stores.","App store; Empirical software engineering; Software distribution; Software release","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-02","","","Software Engineering","","",""
"uuid:9f085396-54ac-4ed6-946a-4fa08ac5243b","http://resolver.tudelft.nl/uuid:9f085396-54ac-4ed6-946a-4fa08ac5243b","Experts and expertise in practices of citizen engagement in climate policy: a comparative analysis of two contrasting cases","van Beek, Lisette (Universiteit Utrecht); Mouter, N. (TU Delft Transport and Logistics); Pelzer, Peter (Universiteit Utrecht); Hajer, Maarten (Universiteit Utrecht); van Vuuren, Detlef (Universiteit Utrecht; Netherlands Environmental Assessment Agency)","","2024","The need for engaging citizens in climate policymaking is increasingly recognised. Despite indications that the form of expert involvement can strongly influence participatory processes, this remains scarcely researched. We analysed two unique and contrasting cases of citizen engagement in national climate mitigation policy: (1) the Irish Citizens’ Assembly (ICA), the first national climate assembly involving live expert presentations and face-to-face deliberations; and (2) the Participatory Value Evaluation (PVE) on Dutch climate policymaking, where more than 10,000 citizens compared policy options in an online environment based on expert-based information on policy effects. Taking a dramaturgical approach, we found that the opening up and closing down of policy options and perspectives was influenced by the setting, staging and scripting of expertise. Apart from providing information on policy options, experts had significant roles in design choices and formulating recommendations, which shaped citizens’ deliberations and policy advice. In deliberative processes, citizens’ deliberations can be further influenced by putting experts in a privileged spot and emphasising their authority, whereas in the setting of an online tool, experts’ design choices may be masked by the fact-like presentation of expertise. Future research should further investigate the role of experts and expertise across a wider range of practices. Nevertheless, we conclude that the high degree of required technical knowledge in climate mitigation policy naturally implies strong expert involvement, which concomitantly steers the results. Alternatively, we may search to enhance citizens’ engagement in guiding climate policymakers by focusing on citizens’ normative perspectives.","Citizen participation; Citizens’ assembly; Climate policy; Expertise; Mini-public; Participatory Value Evaluation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-03","","","Transport and Logistics","","",""
"uuid:960886bc-328f-407a-bf2c-faf9c63700df","http://resolver.tudelft.nl/uuid:960886bc-328f-407a-bf2c-faf9c63700df","Hygrothermal effects on fatigue delamination behavior in composite laminates","Yao, Liaojun (Harbin Institute of Technology); Wang, Jiexiong (Harbin Institute of Technology); He, Yonglyu (National University of Defense Technology); Zhao, Xiuhui (National University of Defense Technology); Chen, Xiangming (Aircraft Strength Research Institute); Liu, J. (Harbin Institute of Technology); Guo, Licheng (Harbin Institute of Technology); Alderliesten, R.C. (TU Delft Group Alderliesten)","","2024","Fatigue delamination growth (FDG) is an important failure in composite structures during their long-term operations. Hygrothermal aging can have significant effects on interlaminar resistance. It is therefore really necessary to explore FDG behavior in composite laminates with hygrothermal aging. Dynamic mechanical thermal analysis (DMTA), mode I FDG experiments and fractographic examinations were conducted to fully investigate hygrothermal aging effects and the corresponding mechanisms on FDG behavior. The DMTA results indicated that environmental aging can induce obvious Tg decrease. Mode I experimental fatigue data interpreted via different Paris-type correlations demonstrated that: Bridging has obvious retardation effects on FDG behavior via the Paris interpretations; The modified Paris relation can well characterize the intrinsic FDG behavior around the crack front; The use of the two-parameter Paris-type relation can appropriately account for R-ratio effects, contributing to a master resistance curve in determining mode I FDG behavior. According to these interpretations, it can be concluded that hygrothermal aging can have adverse effects on mode I FDG behavior. SEM examinations demonstrated that moisture absorption can cause fibre/matrix debonding and resin matrix pores/voids in the composite. However, no obvious difference in damage mechanisms was identified in mode I fatigue delamination for composite with/without environmental conditioning. Both fibre/matrix debonding and matrix brittle fracture were identified on fatigue fracture surfaces. Accordingly, it was concluded that fibre/matrix interface and matrix degradation induced by water absorption were the main reasons for a faster mode I fatigue crack growth in environmental aged composite.","Composite laminates; Delamination; Fatigue; Hygrothermal aging","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-30","","","Group Alderliesten","","",""
"uuid:7ef08cdd-3a17-43a3-8175-961c3f051bee","http://resolver.tudelft.nl/uuid:7ef08cdd-3a17-43a3-8175-961c3f051bee","Optimum-pursuing method for constrained optimization and reliability-based design optimization problems using Kriging model","Meng, Zeng (Hefei University of Technology; Dalian University of Technology); Kong, Lin (Xi'an Modern Chemistry Research Institute); Jiaxiang, Y. (TU Delft Team Marcel Sluiter); Peng, Hao (Dalian University of Technology)","","2024","This paper proposes a new active learning method named as optimum-pursuing method (OPM) from the viewpoint of optimization theory, which aims to provide an effective tool for solving constrained optimization and reliability-based design optimization (RBDO) problems with low computation cost. It uses the cheap Kriging metamodel to replace the expensive physical response. The novelty of the proposed OPM primarily lies in two aspects. First, the OPM utilizes the advantage of the optimization theory rather than sampling technology. By using the augmented Lagrangian approach, it comprehensively considers the objective, constraints, and their relations, thereby automatic identification of important region in the vicinity of the optimum. Second, the accordingly optimum-pursuing function consists of three parts: Kriging mean, Kriging standard deviation, and merit function. Also, the target reliability surface is further considered to enhance the local accuracy of the reliability analysis. The performance of OPM is tested for both deterministic optimization and problems, in which two mathematical and three real-world engineering examples are selected to showcase the feasibility and validity. The results demonstrate that OPM is promising for solving both deterministic optimization and RBDO problems by comparing with the well-known active learning methods.","Active learning; Deterministic optimization; Kriging; Optimum-pursuing method; Reliability-based design optimization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-23","","","Team Marcel Sluiter","","",""
"uuid:55e273f1-f0c0-492f-9b80-0aa730780b2c","http://resolver.tudelft.nl/uuid:55e273f1-f0c0-492f-9b80-0aa730780b2c","Distribution of global sea turtle nesting explained from regional-scale coastal characteristics","Christiaanse, Jakob (TU Delft Coastal Engineering); Antolínez, José A. Á. (TU Delft Coastal Engineering); Luijendijk, Arjen (TU Delft Coastal Engineering; Deltares); Athanasiou, Panagiotis (Deltares); Duarte, Carlos M. (King Abdullah University of Science and Technology); Aarninkhof, S.G.J. (TU Delft Civil Engineering & Geosciences)","","2024","Climate change and human activity threaten sea turtle nesting beaches through increased flooding and erosion. Understanding the environmental characteristics that enable nesting can aid to preserve and expand these habitats. While numerous local studies exist, a comprehensive global analysis of environmental influences on the distribution of sea turtle nesting habitats remains largely unexplored. Here, we relate the distribution of global sea turtle nesting to 22 coastal indicators, spanning hydrodynamic, atmospheric, geophysical, habitat, and human processes. Using state-of-the-art global datasets and a novel 50-km-resolution hexagonal coastline grid (Coastgons), we employ machine learning to identify spatially homogeneous patterns in the indicators and correlate these to the occurrence of nesting grounds. Our findings suggest sea surface temperature, tidal range, extreme surges, and proximity to coral and seagrass habitats significantly influence global nesting distribution. Low tidal ranges and low extreme surges appear to be particularly favorable for individual species, likely due to reduced nest flooding. Other indicators, previously reported as influential (e.g., precipitation and wind speed), were not as important in our global-scale analysis. Finally, we identify new, potentially suitable nesting regions for each species. On average, 23 % of global coastal regions between - 39 ∘ and 48 ∘ latitude could be suitable for nesting, while only 7 % is currently used by turtles, showing that the realized niche is significantly smaller than the fundamental niche, and that there is potential for sea turtles to expand their nesting habitat. Our results help identify suitable nesting conditions, quantify potential hazards to global nesting habitats, and lay a foundation for nature-based solutions to preserve and potentially expand these habitats.","OA-Fund TU Delft","en","journal article","","","","","","","","","Civil Engineering & Geosciences","","Coastal Engineering","","",""
"uuid:58766487-693a-4e90-be77-e0e8c5f79764","http://resolver.tudelft.nl/uuid:58766487-693a-4e90-be77-e0e8c5f79764","Multi-objective design of 3D phononic crystal waveguide by design space trimming","Valiya Valappil, S. (TU Delft Computational Design and Mechanics); Goosen, J.F.L. (TU Delft Computational Design and Mechanics); Aragon, A.M. (TU Delft Computational Design and Mechanics)","","2024","Ultrasonic flowmeters face unique challenges since, in addition to withstanding high fluid pressures, they have to avoid crosstalk, which is the interaction of the signals traveling through the fluid and the solid pipe. To avoid the crosstalk, which leads to poor accuracy or complete loss of the required signal, we develop a mounting mechanism based on phononic crystals (PnCs), which are artificial periodic materials possessing band gaps (BGs) due to Bragg scattering. These PnC structures should also possess high mechanical strength to sustain the fluid pressure. Designing PnCs for such applications is challenging as the BG width and the resistance to mechanical loading are conflicting objectives. To circumvent this, we propose a step-by-step design procedure to optimize both mechanical strength and wave attenuation performance of a single-phase 3D PnC waveguide using parametric sweeping and sensitivity analysis. We use finite element analysis (FEA) to characterize the behavior of the periodic unit cell and the waveguide. Since accurate dynamic FEA at high frequencies is computationally demanding, we develop surrogate models at different levels of the design process. We also consider additive manufacturing aspects in the design procedure, which we validate by 3D-printing the final design and measuring the parameters via computer tomography.","Band structure; Multi-objective design; Parametric sweeping; Phononic crystal; Sensitivity analysis; Static analysis; Transmissibility","en","journal article","","","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:57a4fe0a-75c2-4e5f-887f-d428da31d7d1","http://resolver.tudelft.nl/uuid:57a4fe0a-75c2-4e5f-887f-d428da31d7d1","Volcanic unrest as seen from the magmatic source: Reyðarártindur pluton, Iceland","Rhodes, Emma (Uppsala University); Burchardt, Steffi (Uppsala University); Greiner, Sonja H.M. (Uppsala University; University of Iceland); Mattsson, Tobias (University of St Andrews; Stockholm University); Sigmundsson, Freysteinn (University of Iceland); Schmiedel, T. (TU Delft Resource Engineering); Barker, Abigail K. (Uppsala University); Witcher, Taylor (Uppsala University)","","2024","How the Earth’s crust accommodates magma emplacement influences the signals that can be detected by monitoring volcano seismicity and surface deformation, which are routinely used to forecast volcanic eruptions. However, we lack direct observational links between deformation caused by magma emplacement and monitoring signals. Here we use field mapping and photogrammetry to quantify deformation caused by the emplacement of at least 2.5 km3 of silicic magma in the Reyðarártindur pluton, Southeast Iceland. Our results show that magma emplacement triggered minor and local roof uplift, and that magma reservoir growth was largely aseismic by piecemeal floor subsidence. The occurrence and arrangement of fractures and faults in the reservoir roof can be explained by magmatic overpressure, suggesting that magma influx was not fully accommodated by floor subsidence. The tensile and shear fracturing would have caused detectable seismicity. Overpressure eventually culminated in eruption, as evidenced by exposed conduits that are associated with pronounced local subsidence of the roof rocks, corresponding to the formation of an asymmetric graben at the volcano surface. Hence, the field observations highlight processes that may take place within silicic volcanoes, not accounted for in widely used models to interpret volcanic unrest.","","en","journal article","","","","","","","","","","","Resource Engineering","","",""
"uuid:5b798218-d0c9-4c89-a966-daf4b622fa80","http://resolver.tudelft.nl/uuid:5b798218-d0c9-4c89-a966-daf4b622fa80","Noise-robust latent vector reconstruction in ptychography using deep generative models","Seifert, Jacob (Universiteit Utrecht); Shao, Y. (TU Delft ImPhys/Coene group); Mosk, Allard P. (Universiteit Utrecht)","","2024","Computational imaging is increasingly vital for a broad spectrum of applications, ranging from biological to material sciences. This includes applications where the object is known and sufficiently sparse, allowing it to be described with a reduced number of parameters. When no explicit parameterization is available, a deep generative model can be trained to represent an object in a low-dimensional latent space. In this paper, we harness this dimensionality reduction capability of autoencoders to search for the object solution within the latent space rather than the object space. We demonstrate what we believe to be a novel approach to ptychographic image reconstruction by integrating a deep generative model obtained from a pre-trained autoencoder within an automatic differentiation ptychography (ADP) framework. This approach enables the retrieval of objects from highly ill-posed diffraction patterns, offering an effective method for noise-robust latent vector reconstruction in ptychography. Moreover, the mapping into a low-dimensional latent space allows us to visualize the optimization landscape, which provides insight into the convexity and convergence behavior of the inverse problem. With this work, we aim to facilitate new applications for sparse computational imaging such as when low radiation doses or rapid reconstructions are essential.","","en","journal article","","","","","","","","","","","ImPhys/Coene group","","",""
"uuid:6836db07-c692-40f9-91bc-409feaba2d28","http://resolver.tudelft.nl/uuid:6836db07-c692-40f9-91bc-409feaba2d28","Evolutions of Microstructure and Crystallographic Texture in an Fe-1.2 wt.% Si Alloy After (A)Symmetric Warm Rolling and Annealing","Nguyen-Minh, Tuan (Universiteit Gent); Petrov, R.H. (TU Delft Team Maria Santofimia Navarro; Universiteit Gent); Cicalè, Stefano (Rina Consulting - Centro Sviluppo Materiali); Kestens, L.A.I. (TU Delft Team Maria Santofimia Navarro; Universiteit Gent)","","2024","Rolling and annealing is a crucial technology to produce electrical steel sheets. This technology is not just aimed to control the geometry of steel sheets but more importantly to enhance the magnetic properties of the final products via appropriate microstructure and crystallographic texture. In this study, the evolution of microstructures and textures of an Fe-1.2 wt.% Si alloy through the entire processing route (from reheating, warm rolling to annealing) is monitored by electron back-scatter diffraction. Plastic flows of the material during conventional and asymmetric rolling are analyzed in detail based on geometric parameters of the rolling gaps. Deformation textures are accurately predicted by the full-constraint Taylor and advanced Lamel (ALAMEL) crystal plasticity models. The development of recrystallization textures is accounted for by the plastically stored energy in deformed crystals, which in turn is approximated by the plastically dissipated power (i.e., the Taylor factor) as predicted by the full constraint Taylor model. Although asymmetric warm rolling does not produce an improved texture or microstructure for electrical steels, the present study provides useful information on the evolution of the recrystallization microstructure and texture in steels with a complex strain history after asymmetric warm rolling.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-08","","","Team Maria Santofimia Navarro","","",""
"uuid:370113ef-a243-424d-9e6c-007a1a5d1dd6","http://resolver.tudelft.nl/uuid:370113ef-a243-424d-9e6c-007a1a5d1dd6","Temperature effects on fatigue delamination behavior in thermoset composite laminates","Yao, L. (TU Delft Structural Integrity & Composites; Harbin Institute of Technology; Aircraft Strength Research Institute); Chuai, Mingyue (Harbin Institute of Technology); Li, Hanyue (Harbin Institute of Technology); Chen, Xiangming (Aircraft Strength Research Institute); Quan, D. (TU Delft Structural Integrity & Composites; Shandong University); Alderliesten, R.C. (TU Delft Group Alderliesten); Beyens, M. (Student TU Delft)","","2024","Temperature can significantly affect fatigue delamination growth (FDG) behavior in composites, while fiber bridging has been frequently reported during FDG. The focus of this study was therefore on investigating temperature effects on FDG behavior with fiber bridging. Mode I fatigue delamination experiments were conducted on a thermoset composite laminates M30SC/DT120 at different temperatures. The Paris relation and fatigue resistance curve (i.e. fatigue R-curve) were used to interpret bridging effects on FDG behavior and to explore temperature effects on fiber bridging development. A modified Paris relation was employed to determine the effects of temperature on the intrinsic FDG behavior at the crack front excluding fiber bridging. The Paris interpretations clearly demonstrate that fiber bridging can significantly retard FDG behavior at different temperatures. Temperature can have different effects on fiber bridging development and the intrinsic FDG behavior. Particularly, elevated temperature can promote more bridging fibers, whereas decreased temperature has negligible influence on fiber bridging. When looking at the intrinsic delamination resistance, mode I FDG can accelerate at elevated temperature but decrease at freezing temperature. Fractographic examinations indicate that fiber/matrix interface debonding is the dominant damage mechanism in mode I FDG at different temperatures. Elevated temperature can lead to the weakening of interface adhesion, contributing to faster intrinsic mode I FDG behavior and more fiber bridging development. And a semi-empirical fatigue model based on normalization was finally proposed to determine mode I intrinsic FDG behavior at different temperatures for engineering applications.","Fatigue delamination growth; Fiber bridging retardation; Polymer-matrix composites; Temperature effects","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-10","","","Structural Integrity & Composites","","",""
"uuid:6231852e-42cc-469b-9e77-f9134726cf38","http://resolver.tudelft.nl/uuid:6231852e-42cc-469b-9e77-f9134726cf38","Selecting for a high lipid accumulating microalgae culture by dual growth limitation in a continuous bioreactor","Policastro, G. (TU Delft BT/Environmental Biotechnology; Università degli Studi di Napoli Federico II); Ebrahimi, S. (TU Delft BT/Environmental Biotechnology; Sahand University of Technology); Weissbrodt, D.G. (TU Delft BT/Environmental Biotechnology; Norwegian University of Science and Technology (NTNU)); Fabbricino, Massimiliano (Università degli Studi di Napoli Federico II); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)","","2024","A dual-growth-limited continuous operated bioreactor (chemostat) was used to enhance lipid accumulation in an enrichment culture of microalgae. The light intensity and nitrogen concentration where both limiting factors resulting in high lipid accumulation in the mixed culture. Both conditions of light and nitrogen excess and deficiency were tested. Strategies to selectively enrich for a phototrophic lipid-storing community, based on the use of different nitrogen sources (ammonium vs. nitrate) and vitamin B supplementation in the growth medium, were evaluated. The dual limitation of both nitrogen and light enhanced the accumulation of storage compounds. Ammoniacal nitrogen was the preferred nitrogen source. Vitamin B supplementation led to a doubling of the lipid productivity. The availability of vitamins played a key role in selecting an efficient lipid-storing community, primarily consisting of Trebouxiophyceae (with an 82 % relative abundance among eukaryotic microorganisms). The obtained lipid volumetric productivity (387 mg L−1 d−1) was among the highest reported in literature for microalgae bioreactors. Lipid production by the microalgae enrichment surpassed the efficiencies reported for continuous microalgae pure cultures, highlighting the benefits of mixed-culture photo-biotechnologies for fuels and food ingredients in the circular economy.","Ammonium; Dual growth limitation; Lipid production; Mixed culture microalgae; Vitamin B","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-12","","","BT/Environmental Biotechnology","","",""
"uuid:cc6e2ae1-2500-4339-ab9c-bcb8ba8eb9ce","http://resolver.tudelft.nl/uuid:cc6e2ae1-2500-4339-ab9c-bcb8ba8eb9ce","Integrated CO2 capture and reduction catalysis: Role of γ-Al2O3 support, unique state of potassium and synergy with copper","Pinto, D. (TU Delft ChemE/Catalysis Engineering); Minorello, S. (TU Delft ChemE/Catalysis Engineering); Zhou, Zhouping (Student TU Delft); Urakawa, A. (TU Delft ChemE/Catalysis Engineering)","","2024","Carbon dioxide capture and reduction (CCR) process emerges as an efficient catalytic strategy for CO2 capture and conversion to valuable chemicals. K-promoted Cu/Al2O3 catalysts exhibited promising CO2 capture efficiency and highly selective conversion to syngas (CO + H2). The dynamic nature of the Cu-K system at reaction conditions complicates the identification of the catalytically active phase and surface sites. The present work aims at more precise understanding of the roles of the potassium and copper and the contribution of the metal oxide support. While γ-Al2O3 guarantees high dispersion and destabilisation of the potassium phase, potassium and copper act synergistically to remove CO2 from diluted streams and promote fast regeneration of the active phase for CO2 capture releasing CO while passing H2. A temperature of 350℃ is found necessary to activate H2 dissociation and generate the active sites for CO2 capture. The effects of synthesis parameters on the CCR activity are also described by combination of ex-situ characterisation of the materials and catalytic testing.","Aluminium oxide; Carbon capture and utilisation; Carbon dioxide; CO capture and reduction; Copper catalysts; Heterogeneous catalysis; Potassium; Solid CO sorbents","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-07","","","ChemE/Catalysis Engineering","","",""
"uuid:1451be4e-fb3b-4bf3-b3d6-8957edc50a01","http://resolver.tudelft.nl/uuid:1451be4e-fb3b-4bf3-b3d6-8957edc50a01","How do system and user characteristics, along with anthropomorphism, impact cognitive absorption of chatbots – Introducing SUCCAST through a mixed methods study","Sarraf, Shagun (Indian Institute of Technology Delhi); Kar, Arpan Kumar (Indian Institute of Technology Delhi); Janssen, M.F.W.H.A. (TU Delft Engineering, Systems and Services)","","2024","Chatbots are radically redefining the customer service landscape. With the advent of AI-enabled chatbots, like ChatGPT, organizations are adopting chatbots to provide better customer services; however, the user experience has been given less attention. Building on IS success model and cognitive absorption theory, we posit that system and user characteristics enhance cognitive absorption amongst users, such that the relationship varies between anthropomorphic (e.g., human-like) and non-anthropomorphic chatbots. We undertook a cross-sectional comparative study, which was analyzed using PLS-SEM and fsQCA. Where PLS-SEM provided limited inferential insights about the differences between anthropomorphic and non-anthropomorphic chatbots, the FsQCA analysis resulted in three configurations of attributes for non-anthropomorphic and two configurations for anthropomorphic chatbots, which lead to higher cognitive absorption. The findings extend the existing literature, suggesting that anthropomorphic and non-anthropomorphic chatbots impact cognitive absorption through separate system and user characteristics configurations.","Anthropomorphism; Artificial intelligence; Chatbots; Cognitive absorption; Generative artificial intelligence; Qualitative comparative analysis","en","journal article","","","","","","","","","","Engineering, Systems and Services","","","",""
"uuid:cbc8e62f-0959-4ca6-9d42-bdb2af00c88c","http://resolver.tudelft.nl/uuid:cbc8e62f-0959-4ca6-9d42-bdb2af00c88c","Design optimisation for hybrid metal additive manufacturing for sustainable construction","Baqershahi, Mohammad Hassan (Leibniz Universität); Ayas, C. (TU Delft Computational Design and Mechanics); Ghafoori, Elyas (Leibniz Universität)","","2024","Wire arc additive manufacturing (WAAM) enables the manufacturing of efficient and lightweight structural elements in which material can be utilised wherever needed in an optimised shape, in contrast to standard prismatic profiles used in construction. However, the specific energy consumption (SEC) of WAAM is higher than that of conventional manufacturing (CM) techniques (i.e., hot-rolling) for standard profiles. Therefore, it is an open question whether the material savings through computational design realised via WAAM is environmentally beneficial or not. This systematic study aims to provide a better understanding of the environmental impact of hybrid manufacturing, which is defined as the combination of WAAM and CM rather than using any of them alone. Topology optimisation (TO) is used to design a series of beams with an identical performance (i.e., stiffness) but with a reduced material consumption depending on the hybrid ratio. The environmental impact of the designs has been used to determine when and how hybridisation can become advantageous. The results show that although the optimal proportions of WAAM and CM are dependent on their relative SEC, the hybrid solutions have always been environmentally superior compared to that of WAAM or CM alone for the realistic SEC values, exhibiting up to a 60% reduction in environmental impact compared to that of CM.","Design for sustainability; Environmental assessment; Hybrid manufacturing; Metal additive manufacturing; Topology optimisation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-21","","","Computational Design and Mechanics","","",""
"uuid:39c20063-e4b7-4d77-be36-a49072230d98","http://resolver.tudelft.nl/uuid:39c20063-e4b7-4d77-be36-a49072230d98","Regional design: A transformative approach to planning","Balz, Verena Elisabeth (TU Delft Spatial Planning and Strategy)","","2024","Spatial planning approaches have changed since the 1990s. Major shifts in the institutional architecture of planning schemes have occurred: plan-led planning approaches – characterized by fixed administrative boundaries, statutory frameworks, and paternalistic forms of government – have turned into development-led approaches, in which soft planning follows and facilitates development proposals by market actors and the civil society. Dilemmas that are triggered by an accumulation of competing spatial claims – often due to highly urgent climate mitigation and adaptation measures – and a coupling of structural social, economic and political change have resulted in a greater appreciation of soft, adaptive, and flexible spatial planning approaches. Such approaches involve knowledge about particular areas, draw on place-based community-led initiatives and tailored temporary governance arrangements. They employ more transformative perceptions of natural, metabolic and evolutionary spatial change. In a context of uncertainty, contentiousness and complexity, they aim at unlocking more immediate and effective societal responses to problems in the built environment while maintaining robust, longterm planning rationales at the same time (Van Buuren et al., 2013; Nadin et al., 2021).","spatial design; regional planning; regional design","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-19","","","Spatial Planning and Strategy","","",""
"uuid:62835275-1aec-4d5f-a326-94192279b3bb","http://resolver.tudelft.nl/uuid:62835275-1aec-4d5f-a326-94192279b3bb","Navigating the perils of artificial intelligence: a focused review on ChatGPT and responsible research and innovation","Polyportis, A. (TU Delft BT/Biotechnology and Society); Pachos-Fokialis, N. (TU Delft Economics of Technology and Innovation)","","2024","While the rise of artificial intelligence (AI) tools holds promise for delivering benefits, it is important to acknowledge the associated risks of their deployment. In this article, we conduct a focused literature review to address two central research inquiries concerning ChatGPT and similar AI tools. Firstly, we examine the potential pitfalls linked with the development and implementation of ChatGPT across the individual, organizational, and societal levels. Secondly, we explore the role of a multi-stakeholder responsible research and innovation framework in guiding chatbots’ sustainable development and utilization. Drawing inspiration from responsible research and innovation and stakeholder theory principles, we underscore the necessity of comprehensive ethical guidelines to navigate the design, inception, and utilization of emerging AI innovations. The findings of the focused review shed light on the potential perils of ChatGPT implementation across various societal levels, including issues such as devaluation of relationships, unemployment, privacy concerns, bias, misinformation, and digital inequities. Furthermore, the proposed multi-stakeholder Responsible Research and Innovation framework can empower AI stakeholders to proactively anticipate and deliberate upon AI’s ethical, social, and environmental implications, thus substantially contributing to the pursuit of responsible AI implementation.","OA-Fund TU Delft","en","journal article","","","","","","","","","","","BT/Biotechnology and Society","","",""
"uuid:3f015c0d-f06e-4c04-a2f0-34b28640141a","http://resolver.tudelft.nl/uuid:3f015c0d-f06e-4c04-a2f0-34b28640141a","Approximate dynamic programming for constrained linear systems: A piecewise quadratic approximation approach","He, K. (TU Delft Team Bart De Schutter); Shi, S. (TU Delft Team Bart De Schutter); van den Boom, A.J.J. (TU Delft Team Ton van den Boom); De Schutter, B.H.K. (TU Delft Delft Center for Systems and Control)","","2024","Approximate dynamic programming (ADP) faces challenges in dealing with constraints in control problems. Model predictive control (MPC) is, in comparison, well-known for its accommodation of constraints and stability guarantees, although its computation is sometimes prohibitive. This paper introduces an approach combining the two methodologies to overcome their individual limitations. The predictive control law for constrained linear quadratic regulation (CLQR) problems has been proven to be piecewise affine (PWA) while the value function is piecewise quadratic. We exploit these formal results from MPC to design an ADP method for CLQR problems with a known model. A novel convex and piecewise quadratic neural network with a local–global architecture is proposed to provide an accurate approximation of the value function, which is used as the cost-to-go function in the online dynamic programming problem. An efficient decomposition algorithm is developed to generate the control policy and speed up the online computation. Rigorous stability analysis of the closed-loop system is conducted for the proposed control scheme under the condition that a good approximation of the value function is achieved. Comparative simulations are carried out to demonstrate the potential of the proposed method in terms of online computation and optimality.","Approximate dynamic programming; Constrained linear quadratic regulation; Model predictive control; Neural networks; Reinforcement learning; Value function approximation","en","journal article","","","","","","","","","","Delft Center for Systems and Control","Team Bart De Schutter","","",""
"uuid:74caa480-7234-4270-a231-9f6bb1903951","http://resolver.tudelft.nl/uuid:74caa480-7234-4270-a231-9f6bb1903951","Reset-free data-driven gain estimation: Power iteration using reversed-circulant matrices","Oomen, T.A.E. (TU Delft Team Jan-Willem van Wingerden; Eindhoven University of Technology); Rojas, Cristian R. (KTH Royal Institute of Technology)","","2024","A direct data-driven iterative algorithm is developed to accurately estimate the H∞ norm of a linear time-invariant system from continuous operation, i.e., without resetting the system. The main technical step involves a reversed-circulant matrix that can be evaluated in a model-free setting by performing experiments on the real system.","Data-driven control; Data-driven robust control; Identification and control methods; Identification for control; Input and excitation design","en","journal article","","","","","","This work is part of the research programme VIDI with project number 15698, which is (partly) financed by the Netherlands Organisation for Scientific Research (NWO), by the Digital Futures project EXTREMUM, and by the Swedish Research Council under contract number 2016-06079 (NewLEADS).","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:4ea63b71-5872-4cab-b82d-c703aff84755","http://resolver.tudelft.nl/uuid:4ea63b71-5872-4cab-b82d-c703aff84755","Greening the dike revetment with historic sod transplantation technique in a living lab","van den Hoven, Kim (Wageningen University & Research); Grashof-Bokdam, Carla J. (Wageningen University & Research); Slim, Pieter A. (Wageningen University & Research); Wentholt, Ludolph (STOWA); Peeters, Patrik (Flanders Hydraulics Research); Depreiter, Davy (Flanders Hydraulics Research); Koelewijn, André R. (Deltares); Stoorvogel, Marte M. (NIOZ Royal Netherlands Institute for Sea Research); van den Berg, M. (TU Delft Hydraulic Engineering); Kroeze, Carolien (Wageningen University & Research); van Loon-Steensma, Jantsje M. (Wageningen University & Research; Van Hall Larenstein)","","2024","Coastal flood managers seek to anticipate future flood risk and as a result consider the adaptation of flood defences. Instead of crest heightening, dikes can be adapted to include hydrodynamic reducing vegetated foreshores to form a nature-based hybrid flood defence, for instance; at managed realignments. In this study we investigated the potential of vegetated revetments as a natural continuous connection between the realigned dike and restored foreshore. We applied the historic grass sod transplantation technique with the aim to improve our understanding of the strength of a transplanted sod revetment. In Living Lab Hedwige-Prosperpolder, dikes were available for in-situ experiments during managed realignment preparations. We transplanted grass sods and studied erosion resistance after one growth season. Our results show transplanted sod vegetation continued to grow and started to attach to the clay layer. While erosion occurred under extreme wave impact and overflow, the sod pulling method revealed individual sod strength. In conclusion, sod transplantation is a good technique to source local material for green realigned dike revetments. A vegetated dike revetment can hereby create a natural continuous connection between the realigned dike and foreshore, which benefits flood protection as well as flora and fauna.","hybrid flood defence; in-situ experiment; living lab Hedwige-Prosperpolder; managed realignment; nature-based flood protection; realigned dike; sod transplantation; vegetated dike revetment","en","journal article","","","","","","","","","","Hydraulic Engineering","","","",""
"uuid:093c0762-24b2-4e78-bd77-99076996de17","http://resolver.tudelft.nl/uuid:093c0762-24b2-4e78-bd77-99076996de17","An integrated single-cell RNA-seq atlas of the mouse hypothalamic paraventricular nucleus links transcriptomic and functional types","Berkhout, J. B. (Leiden University Medical Center); Poormoghadam, D. (Netherlands Institute for Neuroscience NIN - KNAW; Amsterdam UMC); Yi, C. (Amsterdam UMC); Kalsbeek, A. (Netherlands Institute for Neuroscience NIN - KNAW; Amsterdam UMC); Meijer, O. C. (Leiden University Medical Center); Mahfouz, A.M.E.T.A. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center)","","2024","The hypothalamic paraventricular nucleus (PVN) is a highly complex brain region that is crucial for homeostatic regulation through neuroendocrine signaling, outflow of the autonomic nervous system, and projections to other brain areas. In the past years, single-cell datasets of the hypothalamus have contributed immensely to the current understanding of the diverse hypothalamic cellular composition. While the PVN has been adequately classified functionally, its molecular classification is currently still insufficient. To address this, we created a detailed atlas of PVN transcriptomic cell types by integrating various PVN single-cell datasets into a recently published hypothalamus single-cell transcriptome atlas. Furthermore, we functionally profiled transcriptomic cell types, based on relevant literature, existing retrograde tracing data, and existing single-cell data of a PVN-projection target region. Finally, we validated our findings with immunofluorescent stainings. In our PVN atlas dataset, we identify the well-known different neuropeptide types, each composed of multiple novel subtypes. We identify Avp-Tac1, Avp-Th, Oxt-Foxp1, Crh-Nr3c1, and Trh-Nfib as the most important neuroendocrine subtypes based on markers described in literature. To characterize the preautonomic functional population, we integrated a single-cell retrograde tracing study of spinally projecting preautonomic neurons into our PVN atlas. We identify these (presympathetic) neurons to cocluster with the Adarb2+ clusters in our dataset. Further, we identify the expression of receptors for Crh, Oxt, Penk, Sst, and Trh in the dorsal motor nucleus of the vagus, a key region that the pre-parasympathetic PVN neurons project to. Finally, we identify Trh-Ucn3 and Brs3-Adarb2 as some centrally projecting populations. In conclusion, our study presents a detailed overview of the transcriptomic cell types of the murine PVN and provides a first attempt to resolve functionality for the identified populations.","hypothalamus; neuroendocrine; paraventricular; preautonomic; single-cell","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:cf5921b2-6655-41c6-a88e-173e0ac3c93b","http://resolver.tudelft.nl/uuid:cf5921b2-6655-41c6-a88e-173e0ac3c93b","Revealing The Degradation Mechanism of (Sr,Ca)AlSiN3:Eu2+ Phosphor Aged Under Thermal-Moisture-Sulfur Conditions: A Combined Experimental and Ab Initio Study","Guo, Baotong (Fudan University); Wen, Minzhen (Fudan University); Tang, Hongyu (Fudan University); Lishik, Sergey (Center of LED and Optoelectronic Technologies of NAS Belarus); Fan, X. (TU Delft Electronic Components, Technology and Materials; Lamar University College of Engineering); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University; Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences; Fudan Zhangjiang Institute)","","2024","MAlSiN3:Eu2+ (M = Ca, Sr) is commonly used in high-power phosphor-converted white-light-emitting diodes and laser diodes to promote their color-rendering index. However, the wide application of this phosphor is limited by the degradation of its luminescent properties in high-temperature, high-humidity, and high-sulfur-content environment. Here, the degradation mechanism of the (Sr,Ca)AlSiN3:Eu2+ (SCASN) red phosphor under thermal-moisture-sulfur coupling conditions is investigated. Furthermore, by performing first-principles calculations, the hydrolysis mechanism on an atomic scale is assessed. The adsorption energy (Eads) and charge transfer (ΔQ) results showed that H2O chemically adsorbed on the (0 1 0), (3 1 0), and (0 0 1) surfaces of the CaAlSiN3 (CASN) host lattice. The energy barrier for H2O dissociation is only 29.73 kJ mol−1 on the CASN (0 1 0) surface, indicating a high dissociation probability. The formation of NH3, Ca(OH)2, and CaAl2Si2O8 is confirmed by H+ tended to combine with surface N atoms, while OH− combined with the surface Al/Si or Ca atoms. Moreover, ab initio molecular dynamics simulations were performed to further understand the hydrolysis process. This work offers a guidance on the design and applications of luminescent materials in LED packages with higher reliability and stability requirements in harsh environment.","(Sr; Ca)AlSiN:Eu phosphor; degradation mechanism; first-principles calculation; hydrolysis reaction; sulfur and hydrogen sulfide","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:9998406a-cf6f-4d03-adbe-de712b422701","http://resolver.tudelft.nl/uuid:9998406a-cf6f-4d03-adbe-de712b422701","Settlement success of European flat oyster (Ostrea edulis) on different types of hard substrate to support reef development in offshore wind farms","ter Hofstede, R. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Van Oord DMC); Witte, Sterre (NIOZ Royal Netherlands Institute for Sea Research; Rijksuniversiteit Groningen); Kamermans, Pauline (Wageningen University & Research); van Koningsveld, M. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Van Oord DMC); Tonk, Linda (Wageningen University & Research)","","2024","The native European flat oyster (Ostrea edulis) is an ecosystem engineer providing important ecosystem services, but became nearly extinct from the North Sea due to diseases and overfishing. There's a growing interest to restore these oyster reefs for their valuable contribution in re-establishing a rich ecosystem in the North Sea. In order to reintroduce the flat oyster population, the availability of hard substrate is crucial for initial settlement and reef development. Such substrate is offered by the infrastructure in offshore wind farms, by means of quarried rock placed at the base of the wind turbine foundations and on top of cable crossings to prevent scouring of the seabed. Further anthropogenic disturbances of the seabed are largely restricted, making wind farm areas promising sites for oyster reef restoration. For successful oyster reef initiation, offering a suitable type of substrate for larvae settlement is important. Here, we assess the settlement preference of flat oysters on 9 different types of substrate, by comparing total settlement, spat densities and spat survival. Oyster larvae settlement preference based on the total number of spat per surface area of the substrate was the highest for granite, a rock type conventionally used as scour protection in offshore wind farms. The lowest settlement preference was observed for steel and the biodegradable polymer BESE. The experiments were performed in a spatting pond and in a natural bay to be able to compare spat collection under controlled and natural conditions. Settlement rates in the spatting pond were much higher than in the natural environment, though survival rates were lower. Our results provide insight in the settlement preference of the European flat oyster for different types of substrate under controlled and natural conditions. Knowing these favorable substrates and conditions for oyster larvae settlement allows for the selection of pro-active measures that contribute to flat oyster reef restoration in the North Sea.","Flat oyster; Hard substrates; Infrastructure; Offshore wind; Reef restoration; Settlement","en","journal article","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:350b7c3d-c628-407b-8dfb-b327f2205bae","http://resolver.tudelft.nl/uuid:350b7c3d-c628-407b-8dfb-b327f2205bae","Mapping the spatiotemporal variability in global storm surge water levels using satellite radar altimetry","Bij de Vaate, I. (TU Delft Water Resources); Slobbe, D.C. (TU Delft Physical and Space Geodesy); Verlaan, M. (TU Delft Mathematical Physics; Deltares)","","2024","Multi-mission satellite altimetry data have been used to study the spatial and temporal variability in global storm surge water levels. This was done by means of a time-dependent extreme value analysis applied to the monthly maximum detided water levels. To account for the limited temporal resolution of the satellite data, the data were first stacked on a 5∘× 5∘ grid. Moreover, additional scaling was applied to the extreme value analysis for which the scaling factors were determined by means of a resampling method using reanalysis data. In addition to the conventional analysis using data from tide gauges, this study provides an insight in the ocean-wide storm surge properties. Nonetheless, where possible, results were compared to similar information derived from tide gauge data. Except for secular changes, the satellite-derived results are comparable to the information derived from tide gauges (correlation > 0.5), although the tide gauges show more local variability. Where limited correlation was observed for the secular change, it was suggested that the satellites may not be able to fully capture the temporal variability in the short-lived, tropical storms, as opposed to extra-tropical storms.","Extreme value analysis; Global change; Satellite radar altimetry; Sea level; Storm surges","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:e16bfa00-f7c2-4cf8-a815-abb0d54257f6","http://resolver.tudelft.nl/uuid:e16bfa00-f7c2-4cf8-a815-abb0d54257f6","Label synchronization for Hybrid Federated Learning in manufacturing and predictive maintenance","Llasag Rosero, Raúl (University of Coimbra, Centre for Informatics and System); Silva, Catarina (University of Coimbra, Centre for Informatics and System); Ribeiro, Bernardete (University of Coimbra, Centre for Informatics and System); Santos, Bruno F. (TU Delft Air Transport & Operations)","","2024","Artificial Intelligence (AI) is transforming the future of industries by introducing new paradigms. To address data privacy and other challenges of decentralization, research has focused on Federated Learning (FL), which combines distributed Machine Learning (ML) models from multiple parties without exchanging confidential information. However, conventional FL methods struggle to handle situations where data samples have diverse features and sizes. We propose a Hybrid Federated Learning solution with label synchronization to overcome this challenge. Our FedLabSync algorithm trains a feed-forward Artificial Neural Network while alerts that it can aggregate knowledge of other ML architectures compatible with the Stochastic Gradient Descent algorithm by conducting a penalized collaborative optimization. We conducted two industrial case studies: product inspection in Bosch factories and aircraft component Remaining Useful Life predictions. Our experiments on decentralized data scenarios demonstrate that FedLabSync can produce a global AI model that achieves results on par with those of centralized learning methods.","Artificial Neural Network; Federated Learning; Hybrid Federated Learning; Machine Learning; Stochastic Gradient Descent","en","journal article","","","","","","","","","","","Air Transport & Operations","","",""
"uuid:0708f9cb-8de2-43cd-af3c-38bd68ee25f5","http://resolver.tudelft.nl/uuid:0708f9cb-8de2-43cd-af3c-38bd68ee25f5","Synchronized optimization of wind farm start-stop and yaw control based on 3D wake model","Mr. Wang, Q. (TU Delft Wind Energy; Hubei University of Technology); Xu, Tangjie (Hubei University of Technology); von Terzi, D.A. (TU Delft Wind Energy); Xia, Wei (Hubei University of Technology); Wang, Zhenhai (Hubei University of Technology); Zhang, Haoran (Hubei University of Technology)","","2024","In existing wind farms, the overall power output can be increased through yaw control. However, the cooperative control of start/stop, yaw and turbines positions is often overlooked, leading to wake superposition to downstream wind turbines and suboptimal power output. This paper proposes a synchronized optimized method that considers start/stop, yaw and turbines positions control based on a three-dimensional wake model and yaw flow superposition model. The objective function of the proposed strategy is to maximize the power output of the Chapman Ranch (CR) wind farm. Four cases are considered: start-stop, yaw control, start-stop & yaw control and start-stop & yaw & turbines positions control. The particle swarm algorithm is introduced to optimize the wind farm layout. According to the results, considering start-stop, yaw and turbines positions optimization can not only increase the annual power output of the wind farm by 8.85 %, but also avoid the colliding wake in the CR wind farm. However, the other three cases will cause colliding wake in some fields of the CR wind farm. This study provides important guidance on improving the overall power output of existing wind farms.","3D wake model; Optimization; Start-stop; Wind farm layout; yaw control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Wind Energy","","",""
"uuid:6e04b6b9-5aae-4c63-b923-354f13a3085a","http://resolver.tudelft.nl/uuid:6e04b6b9-5aae-4c63-b923-354f13a3085a","The interface structural, electronic and optical properties of ZnO nanowires/Graphene nanohybrid (ZnO NWs/G): Experimental and theoretical DFT investigations","Boukhoubza, Issam (National Institute of Materials Physics); Achehboune, Mohamed (University of Namur); Derkaoui, Issam (University Sidi Mohammed Ben Abdellah); Apostol, Mariana Mihaela (National Institute of Materials Physics; Politehnica University of Bucharest); Basyooni, Mohamed A. (TU Delft Dynamics of Micro and Nano Systems; Selçuk University); Khenfouch, Mohammed (Ibn Zohr University); Nedelcu, Liviu (National Institute of Materials Physics); Enculescu, Ionut (National Institute of Materials Physics); Matei, Elena (National Institute of Materials Physics)","","2024","In this work, a ZnO nanowires/graphene nanohybrid was synthesized by a three steps approach. Copper substrates were covered with graphene by chemical vapor deposition, further ZnO nanowires were electrochemically deposited on the as grown graphene on copper and finally a transfer process was employed for moving the heterostructure onto a different substrate. A comprehensive structural analysis which included scanning electron microscopy, X-ray diffraction and Raman measurements revealed that the ZnO nanowires crystallize in wurtzite structure perpendicular to graphene, the process leading to the formation of a nanohybrid heterostructure. The band gap energy of the ZnO nanowires deposited on graphene was estimated to be 3.11 eV, as calculated from the reflectance spectrum analysis. The GGA-PBE+U within Grimme (DFT-D) approach was used to provide an accurate description of the interface structure in terms of electronic and optical properties, confirming that the decrease in the band gap energy of ZnO nanowires is caused by the interaction with the graphene surface. The findings of this study could serve as an experimental and theoretical reference for upcoming studies on ZnO NWs/Graphene nanohybrid-based optoelectronic applications.","Electrochemical deposition; GGA-PBE+U; Optoelectronic properties; ZnO NWs/Graphene","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-12","","","Dynamics of Micro and Nano Systems","","",""
"uuid:f8962315-d49a-498b-944f-6bdbd421f6cf","http://resolver.tudelft.nl/uuid:f8962315-d49a-498b-944f-6bdbd421f6cf","Impact of calibrating a low-cost capacitance-based soil moisture sensor on AquaCrop model performance","Adla, Soham (Technische Universität München); Bruckmaier, Felix (Technische Universität München); Arias-Rodriguez, Leonardo F. (Technische Universität München); Tripathi, Shivam (Indian Institute of Technology Kanpur); Pande, S. (TU Delft Water Resources); Disse, Markus (Technische Universität München)","","2024","Sensor data and agro-hydrological modeling have been combined to improve irrigation management. Crop water models simulating crop growth and production in response to the soil-water environment need to be parsimonious in terms of structure, inputs and parameters to be applied in data scarce regions. Irrigation management using soil moisture sensors requires them to be site-calibrated, low-cost, and maintainable. Therefore, there is a need for parsimonious crop modeling combined with low-cost soil moisture sensing without losing predictive capability. This study calibrated the low-cost capacitance-based Spectrum Inc. SM100 soil moisture sensor using multiple least squares and machine learning models, with both laboratory and field data. The best calibration technique, field-based piece-wise linear regression (calibration r2 = 0.76, RMSE = 3.13 %, validation r2 = 0.67, RMSE = 4.57 %), was used to study the effect of sensor calibration on the performance of the FAO AquaCrop Open Source (AquaCrop-OS) model by calibrating its soil hydraulic parameters. This approach was tested during the wheat cropping season in 2018, in Kanpur (India), in the Indo-Gangetic plains, resulting in some best practices regarding sensor calibration being recommended. The soil moisture sensor was calibrated best in field conditions against a secondary standard sensor (UGT GmbH. SMT100) taken as a reference (r2 = 0.67, RMSE = 4.57 %), followed by laboratory calibration against gravimetric soil moisture using the dry-down (r2 = 0.66, RMSE = 5.26 %) and wet-up curves respectively (r2 = 0.62, RMSE = 6.29 %). Moreover, model overfitting with machine learning algorithms led to poor field validation performance. The soil moisture simulation of AquaCrop-OS improved significantly by incorporating raw reference sensor and calibrated low-cost sensor data. There were non-significant impacts on biomass simulation, but water productivity improved significantly. Notably, using raw low-cost sensor data to calibrate AquaCrop led to poorer performances than using the literature. Hence using literature values could save sensor costs without compromising model performance if sensor calibration was not possible. The results suggest the essentiality of calibrating low-cost soil moisture sensors for crop modeling calibration to improve crop water productivity.","AquaCrop; Calibration; Crop modeling; Low-cost soil moisture sensor; Machine learning; Water productivity","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:c18d2ca0-48c3-4cbb-af67-ae9e6764be68","http://resolver.tudelft.nl/uuid:c18d2ca0-48c3-4cbb-af67-ae9e6764be68","An adaptive agent-based approach for instant delivery order dispatching: Incorporating task buffering and dynamic batching strategies","Lu, Miaojia (Tongji University; Ministry of Education, Shanghai); Yan, Xinyu (The Hong Kong Polytechnic University); Sharif Azadeh, S. (TU Delft Transport and Planning); Wang, P. (TU Delft Transport and Planning; Tongji University)","","2024","The volume of instant delivery has witnessed a significant growth in recent years. Given the involvement of numerous heterogeneous stakeholders, instant delivery operations are inherently characterized by dynamics and uncertainties. This study introduces two order dispatching strategies, namely task buffering and dynamic batching, as potential solutions to address these challenges. The task buffering strategy aims to optimize the assignment timing of orders to couriers, thereby mitigating demand uncertainties. On the other hand, the dynamic batching strategy focuses on alleviating delivery pressure by assigning orders to couriers based on their residual capacity and extra delivery distances. To model the instant delivery problem and evaluate the performances of order dispatching strategies, Adaptive Agent-Based Order Dispatching (ABOD) approach is developed, which combines agent-based modelling, deep reinforcement learning, and the Kuhn-Munkres algorithm. The ABOD effectively captures the system's uncertainties and heterogeneity, facilitating stakeholders learning in novel scenarios and enabling adaptive task buffering and dynamic batching decision-makings. The efficacy of the ABOD approach is verified through both synthetic and real-world case studies. Experimental results demonstrate that implementing the ABOD approach can lead to a significant increase in customer satisfaction, up to 275.42%, while simultaneously reducing the delivery distance by 11.38% compared to baseline policies. Additionally, the ABOD approach exhibits the ability to adaptively adjust buffering times to maintain high levels of customer satisfaction across various demand scenarios. As a result, this approach offers valuable support to logistics providers in making informed decisions regarding order dispatching in instant delivery operations.","Agent-based modelling; Deep reinforcement learning; Dynamic batching; Instant delivery; Task buffering","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:a568ba90-4266-4e09-9f5d-5be3b52116b3","http://resolver.tudelft.nl/uuid:a568ba90-4266-4e09-9f5d-5be3b52116b3","Thermally self-sufficient process for single-step coproduction of methanol and dimethyl ether by CO2 hydrogenation","Vaquerizo, L. (TU Delft ChemE/Product and Process Engineering; University of Valladolid); Kiss, A.A. (TU Delft ChemE/Product and Process Engineering)","","2024","Methanol and DME are highly efficient fuels and relevant building blocks that can be synthesized by CO2 hydrogenation. While several alternatives for methanol production by CO2 hydrogenation have already been developed at a commercial scale, DME production is still based on methanol dehydration. In this sense, the development of bifunctional methanol synthesis/dehydration catalysts is a clear opportunity for the simultaneous coproduction of methanol and DME in a single-step process. Although a few alternatives for DME-methanol coproduction have been proposed, either they need external fuels or refrigerants, or part of the CO2 used as raw material is purged, resulting in a loss of methanol and DME yields. This work presents a novel thermally self-sufficient process that hydrogenates CO2 into methanol and DME in a single reactor at 100 % yield (only water as a byproduct at 0.94 kgwater/kgproduct), that only consumes air, cooling water (0.006 m3 water/kgproducts) and electricity (net CO2 emissions of −1.20 or 0.64 kgCO2eq/kgproducts when the plant is operated with green or grey electricity, respectively). The innovative design, based on the combination of a top-divided wall column, an integrated heat network, and limited pressure drop in the reaction-separation loop, results in a thermally self-sufficient process that uses only 0.76 kWh per kg products.","Dividing-wall column; Dual catalyst; Energy efficiency; Process design; Process integration","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:fc0cc2b0-b2e5-4c69-a32c-fac5d145b70b","http://resolver.tudelft.nl/uuid:fc0cc2b0-b2e5-4c69-a32c-fac5d145b70b","Volumetric Pothole Detection from UAV-Based Imagery","Chen, Siyuan (University College Dublin; Hunan Institute of Science and Technology); Laefer, Debra F. (New York University; University College Dublin); Zeng, Xiangding (Hunan Institute of Science and Technology); Truong-Hong, Linh (TU Delft Optical and Laser Remote Sensing); Mangina, Eleni (University College Dublin)","","2024","Road networks are essential elements of a community's infrastructure and need regular inspection. Present practice requires traffic interruptions and safety risks for inspectors. The road detection system based on vehicle-mounted lasers is also quite mature, offering advantages such as high-precision defect detection, high automation, and fast detection speed. However, it does have drawbacks such as high equipment procurement and maintenance costs, limited flexibility, and insufficient coverage range. Therefore, this paper proposes a low-cost unmanned aerial vehicle (UAV)-based alternative using imagery for automatic road pavement inspection focusing on pothole detection and classification. A slicing-based method, entitled the Pavement Pothole Detection Algorithm, is applied to the imagery after it is converted into a three-dimensional point cloud. When compared with manually extracted results, the proposed UAV-structure-from-motion (SfM) method and the associated algorithm achieved 0.01 m level accuracy for pothole depth detection and maximum errors of 0.0053 m3 in volume evaluation for cases studies of both a road and a bridge deck.","Pavement evaluation; Photogrammetry; Point cloud; Structure from motion (SfM); Unmanned aerial vehicle (UAV)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-27","","","Optical and Laser Remote Sensing","","",""
"uuid:bcdbec1a-009e-4c63-a6c6-841d22bc7270","http://resolver.tudelft.nl/uuid:bcdbec1a-009e-4c63-a6c6-841d22bc7270","Modeling low saline carbonated water flooding including surface complexes","Alvarez, A. C. (Universidade Federal do Rio de Janeiro); Bruining, J. (TU Delft Reservoir Engineering); Marchesin, D. (Instituto Nacional de Matemática Pura e Aplicada - IMPA)","","2024","Carbonated water flooding (CWI) increases oil production due to favorable dissolution effects and viscosity reduction. Accurate modeling of CWI performance requires a simulator with the ability to capture the true physics of such process. In this study, compositional modeling coupled with surface complexation modeling (SCM) are done, allowing a unified study of the influence in oil recovery of reduction of salt concentration in water. The compositional model consists of the conservation equations of total carbon, hydrogen, oxygen, chloride and decane. The coefficients of such equations are obtained from the equilibrium partition of chemical species that are soluble both in oleic and the aqueous phases. SCM is done by using the PHREEQC program, which determines concentration of the master species. Estimation of the wettability as a function of the Total Bound Product (TBP) that takes into account the concentration of the complexes in the aqueous, oleic phases and in the rock walls is performed. We solve analytically and numerically these equations in 1 - D in order to elucidate the effects of the injection of low salinity carbonated water into a reservoir containing oil equilibrated with high salinity carbonated water.","Carbonate water flooding; Conservation laws; Surface complexation modeling; Wettability","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-01","","","Reservoir Engineering","","",""
"uuid:eb98389a-10c5-4e3c-b199-a1de87e81618","http://resolver.tudelft.nl/uuid:eb98389a-10c5-4e3c-b199-a1de87e81618","Autogenous deformation-induced stress evolution in cementitious materials considering viscoelastic properties: A review of experiments and models","Liang, M. (TU Delft Materials and Environment); Xie, J. (TU Delft Materials and Environment); He, S. (TU Delft Materials and Environment); Chen, Y. (TU Delft Materials and Environment); Schlangen, E. (TU Delft Materials and Environment); Šavija, B. (TU Delft Materials and Environment)","","2024","Early-age cracking risk induced by autogenous deformation is high for cementitious materials of low water-binder ratios. The autogenous deformation, viscoelastic properties, and stress evolution are three important factors for understanding and quantifying the early-age cracking risk. This paper systematically reviewed the experimental and modelling techniques of the three factors. It is found that the Temperature Stress Testing Machine is a unified experimental method for all these three factors, with a strain-controlled mode for stress evolution, hourly-repeated loading scheme for viscoelastic properties, and free condition for autogenous deformation. Such unified method provides basis for developing various models. By coupling a hydration model for volume fractions of hydrates, a homogenization model for upscaling of viscoelastic properties, and capillary pressure theory for self-desiccation shrinkage, a unified model directly mapping the mix design to the early-age stress can be constructed, which can help optimize the mix design to reduce the early-age cracking risk.","Autogenous deformation; Cementitious materials; Creep; Early-age cracking; Elastic modulus; Relaxation; Stress evolution","en","review","","","","","","","","","","","Materials and Environment","","",""
"uuid:1da56723-f07c-4f83-bb56-7401482d9071","http://resolver.tudelft.nl/uuid:1da56723-f07c-4f83-bb56-7401482d9071","RFID-based material passport system in a recycled concrete circular chain","Vahidi, A. (TU Delft Resources & Recycling); Gebremariam, A.T. (TU Delft Resources & Recycling); Di Maio, F. (TU Delft Resources & Recycling); Meister, K.R. (TU Delft Environmental Technology and Design); Koulaeian, T. (TU Delft Resources & Recycling); Rem, P.C. (TU Delft Resources & Recycling)","","2024","The construction industry urgently requires a resilient information system for effective coordination of data transmission among various stakeholders, including both the public and private sectors. Such an advanced digital solution would not only enhance transparency along the value chain but also improve both the quality of and confidence in recycled materials. Achieving circularity and reducing environmental impact are closely tied to the efficient management of material flows and life cycles. Within this context, Material Passports (MPs) are posited as a foundational element, particularly when integrated with a digital database. This integration is particularly beneficial for increasing the circularity of concrete, beginning with end-of-life concrete, a major contributor to global construction and demolition waste. MPs effectively transmit crucial information about the quality of recycled aggregates, thereby enabling their use in future construction projects. This study explores the feasibility of employing Radio Frequency Identification (RFID) technology as an MP, aiming to enhance sustainability in the concrete industry by improving transparency, traceability, and data reliability in the recycled concrete supply chain. Extensive laboratory tests carried out in three distinct experimental phases revealed that RFID tags exhibit remarkable resilience to mechanical stress typical in the supply chain and consistently maintain readability when embedded in concrete. The water content in concrete samples was identified as a significant factor influencing initial tag readability, although readability improved over time. Other factors, such as the type of aggregates, particle size distribution, and proximity to steel rebar, had minimal to modest impacts on tag performance. Additionally, the study confirmed that the readability of RFID tags remains robust at typical transport speeds, which highlights the potential of an RFID-based system in advancing supply chain management. This study provides a solid foundation for future research in this evolving area.","Circular economy; End-of-life concrete; Material passport; Recycling; RFID","en","journal article","","","","","","","","","","","Resources & Recycling","","",""
"uuid:97830b21-60d2-48bf-81c5-02112c1348c6","http://resolver.tudelft.nl/uuid:97830b21-60d2-48bf-81c5-02112c1348c6","Responsible mission governance: An integrative framework and research agenda","Wiarda, M.J. (TU Delft Values Technology and Innovation); Janssen, Matthijs J. (Universiteit Utrecht); Coenen, Tom B.J. (University of Twente); Doorn, N. (TU Delft Values Technology and Innovation)","","2024","Governance lies at the heart of instigating, steering, and creating the conditions for mission-oriented transitions that potentially help resolve some of our grand societal challenges. In doing so, policymakers will need to navigate both epistemic and normative considerations to develop, implement, and evaluate missions responsibly. A number of scholars have therefore expressed the need for a better conceptualization of responsible mission governance as a procedural approach, particularly with the aim of coping with the complexity, uncertainty, and contestation that render these wicked problems intractable. In this paper we develop an integrative framework for responsible mission governance by taking wickedness dimensions as our entry point. Accordingly, we argue that responsible mission governance should integrate various complementary governance responsibilities (e.g., reflexivity) and modes (e.g., reflexive governance) that potentially improve the effectiveness and desirability of missions.","Innovation policy; Mission; Responsible innovation; Societal challenge; Transformation; Transition","en","journal article","","","","","","","","","","Values Technology and Innovation","","","",""
"uuid:86a53abd-52a3-4ec7-b733-e4fdf374ab22","http://resolver.tudelft.nl/uuid:86a53abd-52a3-4ec7-b733-e4fdf374ab22","Embedding Fe(0) electrocoagulation in a biologically active As(III) oxidising filter bed","Roy, M. (TU Delft Sanitary Engineering); Kraaijeveld, E. (TU Delft Sanitary Engineering); Gude, J.C.J. (NX Filtration); van Genuchten, Case M. (Geological Survey of Denmark and Greenland); Rietveld, L.C. (TU Delft Sanitary Engineering); van Halem, D. (TU Delft Sanitary Engineering)","","2024","Long-term consumption of groundwater containing elevated levels of arsenic (As) can have severe health consequences, including cancer. To effectively remove As, conventional treatment technologies require expensive chemical oxidants to oxidise neutral arsenite (As(III)) in groundwater to negatively charged arsenate (As(V)), which is more easily removed. Rapid sand filter beds used in conventional aeration-filtration to treat anaerobic groundwater can naturally oxidise As(III) through biological processes but require an additional step to remove the generated As(V), adding complexity and cost. This study introduces a novel approach where As(V), produced through biological As(III) oxidation in a sand filter, is effectively removed within the same filter by embedding and operating an iron electrocoagulation (FeEC) system inside the filter. Operating FeEC within the biological filter achieved higher As(III) removal (81 %) compared to operating FeEC in the filter supernatant (67 %). This performance was similar to an analogous embedded-FeEC system treating As(V)-contaminated water (85 %), confirming the benefits of incorporating FeEC in a biological bed for comparable As(III) and As(V) removal. However, operating FeEC in the sand matrix consumed more energy (14 Wh/m3) compared to FeEC operated in a water matrix (7 Wh/m3). The efficiency of As removal increased and energy requirements decreased in such embedded-FeEC systems by deep-bed infiltration of Fe(III)-precipitates, which can be controlled by adjusting flow rate and pH. This study is one of the first to demonstrate the feasibility of embedding FeEC systems in sand filters for groundwater arsenic removal. Such systems capitalise on biological As(III) oxidation in aeration-filtration, effectively eliminating As(V) within the same setup without the need for chemicals or major modifications.","Arsenic; Drinking water; Groundwater; Iron electrocoagulation","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:719350bd-9ac1-4ba8-93d1-b6edf3e7852c","http://resolver.tudelft.nl/uuid:719350bd-9ac1-4ba8-93d1-b6edf3e7852c","Potential of BREEAM-C to support building circularity assessment: Insights from case study and expert interview","Wong, Dominique Hiulong (Universiteit Leiden); Zhang, Chunbo (Universiteit Leiden; University College London (UCL)); Di Maio, F. (TU Delft Resources & Recycling); Hu, Mingming (Universiteit Leiden)","","2024","Lack of knowledge and tools hampers circular transition in the construction industry. This study analyzes the potential of a framework of circular indicators put forward by the Building Research Establishment Environmental Assessment Method (BREEAM-C) as an answer to the prevailing need of a metric for building circularity assessment to promote circular construction. A qualitative analysis approach is adopted, involving literature review, comparative case study and semi-structured interviews conducted for collecting expert opinions. An in-depth scrutiny of the BREEAM-C indicators revealed that they are rooted in circular principles, cover building circularity realizable through circular strategies, and have given due consideration to circularity in different impact areas, structural layers and life-cycle stages of buildings. Moreover, BREEAM-C indicators not only show capacity in identifying CE-related practices implemented, but also serve as benchmarks testifying that CE principles/strategies are incorporated in the design, construction, operation and management of the buildings. Despite having room for expansion, BREEAM-C has proven to be applicable and practical with potential for use in Taiwan as confirmed by expert opinions. Nevertheless, adaptation/localization is required to cater for different concerns with respect to climate and safety as well as local context and legislations.","BREEAM; Building circularity; Built environment; Circular construction; Circular economy; Circularity assessment","en","journal article","","","","","","","","","","","Resources & Recycling","","",""
"uuid:3dcfb0ec-d106-4134-851f-c8d935054f53","http://resolver.tudelft.nl/uuid:3dcfb0ec-d106-4134-851f-c8d935054f53","CFD-DEM study on agglomeration and spout-assisted fluidization of cohesive particles","Zou, Yi (Southeast University – Monash University Joint Research Institute); Zou, Ruiping (Monash University); Wu, Yongli (TU Delft Resources & Recycling)","","2024","The agglomeration of cohesive particles can deteriorate fluidization quality and cause the defluidization of a bed, which is a common issue found in the applications of fluidized beds. This study aims to gain a better understanding of particle cohesion on agglomeration/fluidization behaviors and the effective methods for achieving a better fluidization quality, through numerical simulations based on the coupled approach of computational fluid dynamics and discrete element method (CFD-DEM). The effects of particle cohesion, gas velocities or flow conditions, and the bed geometry on the agglomeration and fluidization behaviors are analyzed. It is shown that the increase of particle cohesion can lead to deteriorated particle mixing, significant agglomeration of particles, and defluidization of the bed; the agglomeration-induced defluidization of highly cohesive particles is difficult to mitigate in a conventional flat-bottom fluidized bed. As large-sized agglomerates are more frequently found in the bottom of the bed, the spouted gas flow is then utilized and demonstrated to be effective in assisting the deagglomeration and fluidization of highly cohesive particles. Through the comparison of various spouted beds and spouted fluidized beds, the effective design of the bed bottom is identified for achieving a higher fluidization quality. Corresponding mechanisms underlying spout-assisted deagglomeration and fluidization are found to be much related to not only the enhanced particle-fluid but also particle-wall interactions in the confined space of a conical bed bottom, thus explaining the effectiveness and the importance of the bottom conical geometry of spouted beds. The obtained findings may help to understand the agglomeration-induced defluidization of fluidized beds and assist the fluidization of highly cohesive particles by the effective design of spouted beds.","Agglomeration; CFD-DEM; Cohesive particles; Fluidization; Spouted bed","en","journal article","","","","","","","","","","","Resources & Recycling","","",""
"uuid:31036a2d-8b58-4fd6-917d-9570168153c5","http://resolver.tudelft.nl/uuid:31036a2d-8b58-4fd6-917d-9570168153c5","Application of thermodynamics at different scales to describe the behaviour of fast reacting binary mixtures in vapour-liquid equilibrium","Lasala, Silvia (Lorraine University); Samukov, Konstantin (Lorraine University); Polat, H.M. (TU Delft Engineering Thermodynamics); Lachet, Véronique (IFP Energies Nouvelles); Herbinet, Olivier (Lorraine University); Privat, Romain (Lorraine University); Jaubert, Jean Noël (Lorraine University); Moultos, O. (TU Delft Process and Energy); De Ras, Kevin (Universiteit Gent); Vlugt, T.J.H. (TU Delft Process and Energy)","","2024","The use of reactive working fluids in thermodynamic cycles is currently being considered as an alternative to inert working fluids, because of the preliminarily attested higher energy-efficiency potential. The current needs to simulate their use in thermodynamic cycles, which may operate in liquid, vapour or vapour-liquid state, are an accurate real-fluid equation of state and ideal gas thermochemical properties of each molecule constituting the mixture, to calculate the equilibrium constant. To this end, the appeal to a multi-scale theoretical methodology is paramount and its definition represents the objective of the present work. This methodology is applied and validated on the system N2O4 ⇌ 2NO2. Firstly, the equations solved for simultaneous two-phase and reaction equilibrium are presented. Secondly, ideal gas thermochemical properties of N2O4 and NO2 are computed at atomic scale by quantum mechanics simulations. Then, to apply the selected cubic equation of state, pure-component properties of the species forming the reactive mixture (critical point coordinates and acentric factor) are required as input. However, these properties are not measurable, since NO2 and N2O4 do not exist in nature as pure components. To get around this difficulty, the methodology relies on molecular Monte Carlo simulations of the pure N2O4 and NO2, as well as on the reactive N2O4 ⇌ 2NO2, enabling the determination of those missing pure-component properties and thus the calculation, on a macroscopic scale, of the reactive mixture properties. Finally, the comparison of calculated mixture properties with available experimental data leads to validate the accuracy of the proposed methodology.","Equations of state; Monte Carlo simulations; Quantum Mechanics simulations; Reactive mixtures; Vapour-liquid equilibrium","en","journal article","","","","","","","","","","Process and Energy","Engineering Thermodynamics","","",""
"uuid:3927a57e-328c-4607-9ca3-652f97ecf648","http://resolver.tudelft.nl/uuid:3927a57e-328c-4607-9ca3-652f97ecf648","Aberration-driven tilted emission in degenerate cavities","Gurevich, S. V. (University of Münster; University of the Balearic Islands); Maucher, F. (TU Delft Optical Technologies; University of the Balearic Islands); Javaloyes, J. (University of the Balearic Islands)","","2024","The compensation of chromatic dispersion opened new avenues and extended the level of control upon pattern formation in the temporal domain. In this paper, we propose the use of a nearly degenerate laser cavity as a general framework allowing for the exploration of higher contributions to diffraction in the spatial domain. Our approach leverages the interplay between optical aberrations and the proximity to the self-imaging condition, which allows us to cancel or reverse paraxial diffraction. As an example, we show how spherical aberrations materialize into a transverse bi-Laplacian operator and, thereby, explain the stabilization of temporal solitons traveling off-axis in an unstable mode-locked broad-area surface-emitting laser. We disclose an analogy between these regimes and the dynamics of a quantum particle in a double-well potential.","","en","journal article","","","","","","","","","","","Optical Technologies","","",""
"uuid:ac6b78bb-57f2-4420-85d9-a308469263fb","http://resolver.tudelft.nl/uuid:ac6b78bb-57f2-4420-85d9-a308469263fb","Experimental and numerical study on earthquake-fire coupling failure mechanism of steel cylindrical tanks","Men, Jinkun (South China University of Technology; Guangdong Provincial Science and Technology Collaborative Innovation Center for Work Safety; Katholieke Universiteit Leuven); Chen, Guohua (South China University of Technology; Guangdong Provincial Science and Technology Collaborative Innovation Center for Work Safety); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Katholieke Universiteit Leuven; Universiteit Antwerpen); Wu, Yue (South China University of Technology; Guangdong Provincial Science and Technology Collaborative Innovation Center for Work Safety); Huang, Hailing (South China University of Technology; Guangdong Provincial Science and Technology Collaborative Innovation Center for Work Safety)","","2024","An earthquake-triggered fire domino scenario (E-FDS) is an example of a typical multi-hazard coupling event. The seismic damage can affect the fire resistance of engineering structures, leading to significant mutually amplified phenomena. In this work, a two-stage experimental program is designed to expound the earthquake-fire coupling failure mechanism of steel cylindrical tanks (SCTs). Quasi-static tests are adopted to simulate the damage characteristics of SCTs under seismic excitation (Stage I). Fire tests are adopted to investigate the fire-resistance performance of pre-damaged SCTs (Stage II). The influences of seismic damage on the fire resistance of SCTs are particularly of interest. Three potential seismic damage degrees are considered. The experimental results show that tank specimens exhibit typical diamond-shaped buckling after Stage I. The coupling failure analysis of SCTs is conducted through sequential thermodynamic coupling simulations. Due to factors such as geometric deformation, residual stress, and thermal radiation absorption capacity, the fire resistance of SCTs is significantly attenuated by seismic damage. For the three damage states, fire resistance time attenuation coefficients (0.868, 0.716, 0.511) and critical temperature attenuation coefficients (0.910, 0.779, 0.672) were obtained. This work provides pivotal insights into the mutually amplified phenomena in E-FDSs.","Coupling failure mechanism; Earthquake-triggered fire domino scenario; Steel cylindrical tanks; Two-stage experimental program","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-13","","","Safety and Security Science","","",""
"uuid:cccce194-9309-4754-b26a-7e1f76973109","http://resolver.tudelft.nl/uuid:cccce194-9309-4754-b26a-7e1f76973109","Using participatory systems approaches to improve healthcare delivery","Lamé, Guillaume (Université Paris-Saclay, Paris); Tako, Antuela (Loughborough University, School of Business and Economics); Kleinsmann, M.S. (TU Delft Design, Organisation and Strategy)","","2024","","","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-13","","Design, Organisation and Strategy","","","",""
"uuid:94b8d501-7ad8-4077-b3c1-620df02a5a27","http://resolver.tudelft.nl/uuid:94b8d501-7ad8-4077-b3c1-620df02a5a27","Oil Spaces: Extended Urbanization from Sea to Land","Hein, C.M. (TU Delft History, Form & Aesthetics)","","2024","Flows of petroleum have shaped buildings, cities and landscape around the world on sea and land. This paper shows how industrially drilled petroleum and its refined products have played a major role in transforming the built environment over the last century and a half, in ways that are often not visible or recognized. Understanding the multiple links between refineries, gas stations, headquarters or cities around the world, and acknowledging the path dependencies that these flows have created, provides a concrete example for extended urbanization and its role in fueling ways of life and visions of progress, modernity, and disaster.
Through detailed international case studies the paper considers petroleum’s role in the development of the built environment and the imagination. It explores how petroleum and its infrastructure have served in shaping extended urbanization as a source of military conflict and political and economic power, inspiring efforts to create territories and reshape geographies and national boundaries. The paper explores ruptures and continuities between colonial and postcolonial frameworks through diverse case studies with diverse functions from around the world, including heritage sites.
By revealing petroleum’s role in organizing and imagining space globally, this paper takes up a key task in imagining the possibilities of a post-oil future. It explores diverse contributions made by students in courses at Delft University of Technology to show visualize them.","petroleumscape; history of urbanism; post-oil futures; extended urbanization","en","abstract","","","","","","","","","","","History, Form & Aesthetics","","",""
"uuid:bfd0d299-b573-4a1d-aab8-a085d9284d87","http://resolver.tudelft.nl/uuid:bfd0d299-b573-4a1d-aab8-a085d9284d87","Blind Polarization Demultiplexing of Shaped QAM Signals Assisted by Temporal Correlations","Bajaj, V. (TU Delft Team Sander Wahls); Van de Plas, Raf (TU Delft Team Raf Van de Plas; VanderBilt University); Wahls, S. (Karlsruhe Institut für Technologie)","","2024","While probabilistic constellation shaping (PCS) enables rate and reach adaption with finer granularity [1] (Cho and Winzer, 2009), it imposes signal processing challenges at the receiver. Since the distribution of PCS-quadrature amplitude modulation (QAM) signals tends to be Gaussian, conventional blind polarization demultiplexing algorithms are not suitable for them [2] (Johnson et al., 1998). It is known that independently and identically distributed (iid) Gaussian signals, when mixed, cannot be recovered/separated from their mixture. For PCS-QAM signals, there are algorithms such as [3] and [4] Dris et al. (2019) and Athuraliya et al. (2004) which are designed by extending conventional blind algorithms used for uniform QAM signals. In these algorithms, an initialization point is obtained by processing only a part of the mixed signal, which have non-Gaussian statistics. In this article, we propose an alternative method wherein we add temporal correlations at the transmitter, which are subsequently exploited at the receiver in order to separate the polarizations. We will refer to the proposed method as frequency domain (FD) joint diagonalization (JD) probability aware-multi modulus algorithm (pr-MMA), and it is suited to channels with moderate polarization mode dispersion (PMD) effects. Furthermore, we extend our previously proposed JD-MMA [5] (Bajaj et al., 2022) by replacing the standard MMA with a pr-MMA, improving its performance. Both FDJD-pr-MMA and JD-pr-MMA are evaluated for a diverse range of PCS (entropy $\mathcal {H}$) of 64-QAM over a first-order PMD channel that is simulated in a proof-of-concept setup. A MMA initialized with a memoryless constant modulus algorithm (CMA) is used as a benchmark. We show that at a differential group delay (DGD) of 10% of symbol period T$_{\text{symb}}$ and 18 dB SNR/pol., JD-pr-MMA successfully demultiplexes the PCS signals, while CMA-MMA fails drastically. Furthermore, we demonstrate that the newly proposed FDJD-pr-MMA is robust against moderate PMD effects by evaluating it over a DGD of up to 40% of T$_{\text{symb}}$. Our results show that the proposed FDJD-pr-MMA successfully equalizes PMD channels with a DGD up to 20% of T$_{\text{symb}}$.","and optical fiber communication; Correlation; Demultiplexing; digital signal processing; Optical fiber dispersion; Polarization demultiplexing; probabilistic constellation shaping; Programmable logic arrays; Quadrature amplitude modulation; Signal processing algorithms; Symbols","en","journal article","","","","","","","","2024-03-14","","","Team Sander Wahls","","",""
"uuid:78b3ee0c-71ac-41f6-8564-53b3e1e4d31c","http://resolver.tudelft.nl/uuid:78b3ee0c-71ac-41f6-8564-53b3e1e4d31c","Measurements of morphodynamics of a sheltered beach along the Dutch Wadden Sea","van der Lugt, M.A. (TU Delft Coastal Engineering; Deltares); Bosma, Jorn W. (Universiteit Utrecht); de Schipper, M.A. (TU Delft Coastal Engineering); Price, Timothy D. (Universiteit Utrecht); van Maarseveen, Marcel C. G. (Universiteit Utrecht); van der Gaag, P. (TU Delft Lab Hydraulic Engineering); Ruessink, Gerben (Universiteit Utrecht); Reniers, A.J.H.M. (TU Delft Environmental Fluid Mechanics); Aarninkhof, S.G.J. (TU Delft Civil Engineering & Geosciences)","","2024","A field campaign was carried out at a sheltered sandy beach with the aim of gaining new insights into the driving processes behind sheltered beach morphodynamics. Detailed measurements of the local hydrodynamics, bed-level changes and sediment composition were collected at a man-made beach on the leeside of the barrier island Texel, bordering the Marsdiep basin that is part of the Dutch Wadden Sea. The dataset consists of (1) current, wave and turbidity measurements from a dense cross-shore array and a 3 km alongshore array; (2) sediment composition data from beach surface samples; (3) high-temporal-resolution RTK-GNSS beach profile measurements; (4) a pre-campaign spatially covering topobathy map; and (5) meteorological data. This paper outlines how these measurements were set up and how the data have been processed, stored and can be accessed. The novelty of this dataset lies in the detailed approach to resolve forcing conditions on a sheltered beach, where morphological evolution is governed by a subtle interplay between tidal and wind-driven currents, waves and bed composition, primarily due to the low-energy (near-threshold) forcing. The data are publicly available at 4TU Centre for Research Data at: https://doi.org/10.4121/19c5676c-9cea-49d0-b7a3-7c627e436541 (Van der Lugt et al., 2023).","","en","journal article","","","","","","","","","Civil Engineering & Geosciences","","Coastal Engineering","","",""
"uuid:6dbba8e0-f142-4308-94a5-9aeb2ee1e734","http://resolver.tudelft.nl/uuid:6dbba8e0-f142-4308-94a5-9aeb2ee1e734","The chromatin landscape of healthy and injured cell types in the human kidney","Gisch, Debora L. (Indiana University - Purdue University); Brennan, Michelle (Saint Louis University); Lake, Blue B. (University of California; San Diego Institute of Science); Basta, Jeannine (Washington University in St. Louis); Keller, Mark S. (Harvard Medical School); P. Gonçalves, Joana (TU Delft Pattern Recognition and Bioinformatics); Migas, L.G. (TU Delft Team Raf Van de Plas); Van de Plas, Raf (TU Delft Team Raf Van de Plas); Lardenoije, R. (TU Delft Pattern Recognition and Bioinformatics)","","2024","There is a need to define regions of gene activation or repression that control human kidney cells in states of health, injury, and repair to understand the molecular pathogenesis of kidney disease and design therapeutic strategies. Comprehensive integration of gene expression with epigenetic features that define regulatory elements remains a significant challenge. We measure dual single nucleus RNA expression and chromatin accessibility, DNA methylation, and H3K27ac, H3K4me1, H3K4me3, and H3K27me3 histone modifications to decipher the chromatin landscape and gene regulation of the kidney in reference and adaptive injury states. We establish a spatially-anchored epigenomic atlas to define the kidney’s active, silent, and regulatory accessible chromatin regions across the genome. Using this atlas, we note distinct control of adaptive injury in different epithelial cell types. A proximal tubule cell transcription factor network of ELF3, KLF6, and KLF10 regulates the transition between health and injury, while in thick ascending limb cells this transition is regulated by NR2F1. Further, combined perturbation of ELF3, KLF6, and KLF10 distinguishes two adaptive proximal tubular cell subtypes, one of which manifested a repair trajectory after knockout. This atlas will serve as a foundation to facilitate targeted cell-specific therapeutics by reprogramming gene regulatory networks.","","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:1adbdab8-a4fa-408b-a933-2825db8aeb36","http://resolver.tudelft.nl/uuid:1adbdab8-a4fa-408b-a933-2825db8aeb36","Contribution of capital goods production to social impacts: A life cycle perspective for a circular desalination plant","Tsalidis, G.A. (TU Delft BT/Biotechnology and Society; Communication and Knowledge Technologies; Brunel University); Kokubo Roche, A.M.B. (TU Delft BT/Biotechnology and Society); Randazzo, Serena (Università degli Studi di Palermo); Posada Duque, J.A. (TU Delft BT/Biotechnology and Society)","","2024","The production of capital goods is often ignored in the life cycle inventory phase of life cycle assessment studies. In this study, we investigated whether capital goods production, i.e., manufacturing of capital equipment and construction of infrastructure, and operation affect the results of the social life cycle assessment (S-LCA), using a case study of a desalination plant with multiple co-products in Lampedusa, Italy. The assessment was conducted using the PSILCA database to evaluate 20 impact subcategories and four stakeholder categories: Workers, Value chain actors, Society and Local community. Monetary data were collected for the manufacturing of equipment, labor and miscellaneous work during plant construction, working hours of employees during operation, consumed electricity and chemicals, and recovered materials during operation. Furthermore, multi-functionality was addressed through substitution, system expansion, and economic allocation to examine how these approaches affected the results. The functional unit was 1 m3 industrial water. Equipment manufacturing and plant construction contributed up to 15% to stakeholder categories and between 2% and 75% to impact subcategories of the substitution approach, and up to 51% for impact subcategories of system expansion and economic allocation. Equipment manufacturing and plant construction contributed to a high extent to “Health and safety” (of Workers), “Discrimination” and “Local employment” due to the construction and electrical sectors. Credits in substitution lead to a lower contribution of the operational stage and negative societal impact values. If S-LCA practitioners must limit the considered impact subcategories, for generic or site-specific analysis, the “Health and safety” (Workers), “Local employment”, and “Fair salary” should be investigated.","Construction; Infrastructure; Local community; PSILCA; Reference scale approach; Social life cycle assessment; Worker","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-26","","","BT/Biotechnology and Society","","",""
"uuid:6db4d1fa-a4ec-4374-8154-e226fdbf194d","http://resolver.tudelft.nl/uuid:6db4d1fa-a4ec-4374-8154-e226fdbf194d","Robust additive manufacturable Ni superalloys designed by the integrated optimization of local elemental segregation and cracking susceptibility criteria","Yu, Hao (Northeastern University China); Fu, Jiabo (Northeastern University China); Wang, Chenchong (Northeastern University China); Chen, Yinping (Northeastern University China); Wang, Lingyu (Northeastern University China); Fang, Haixing (European Synchrotron Radiation Facility; Grenoble INP; Université Grenoble Alpes; Université de Lyon); Li, Jinguo (Chinese Academy of Sciences); van der Zwaag, S. (TU Delft Group Garcia Espallargas); Xu, Wei (Northeastern University China)","","2024","To achieve an effective design of additively manufacturable Ni superalloys with decent service performance, a hybrid computational design model has been developed, where the strategy to tailor local elemental segregations was integrated within a scheme of minimizing the cracking susceptibility. More specifically, the phase boundary of primary NbC / γ matrix was introduced into the design routine to tune the spatial distribution of critical solutes at an atomic scale, thereby inhibiting the formation of borides and segregation-induced cracking. Based on the output of the design, new grades of Ni superalloy have been developed with excellent additive manufacturability, as confirmed by the robustness of printing parameters in fabricating low-defect-density samples. The capability of the phase boundaries to evenly distribute boron atoms was validated experimentally, and the cracking induced by uncontrolled boron segregation at grain boundaries was effectively prevented. The newly designed alloys showed good tensile properties and decent oxidation resistance at different service temperatures, which are comparable to those of conventionally produced superalloys. The finding that phase boundaries can be employed to prevent undesirable clustering of boron atoms can be extended to manipulate the distributions of other critical elements, which provides a new path for designing novel Ni superalloys with balanced printability and mechanical properties.","Additive manufacturability; Boron segregation; Computational design; Ni superalloys; Phase boundaries","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-08","","","Group Garcia Espallargas","","",""
"uuid:cef343c1-e212-4ad0-a5ba-bdc4219ef106","http://resolver.tudelft.nl/uuid:cef343c1-e212-4ad0-a5ba-bdc4219ef106","Structure and bonding in TiNiSi type LaMgSnH intermetallic hydride","Yartys, Volodymyr A. (Institute for Energy Technology); Denys, Roman V. (Institute for Energy Technology); Akselrud, Lev G. (Ivan Franko National University of Lviv, Lviv); Vajeeston, Ponniah (Universitetet i Oslo); Dankelman, B.J.R. (TU Delft RID/TS/Technici Pool); Plomp, J. (TU Delft RST/Neutron and Positron Methods in Materials; TU Delft RID/TS/Instrumenten groep); Block, Theresa (University of Münster); Pöttgen, Rainer (University of Münster); Wragg, David (Institute for Energy Technology)","","2024","The work was aimed on reaching a better understanding of the effect of magnesium as a component of the hydride-forming LaMgSn intermetallic compound crystallising with the orthorhombic TiNiSi type of structure on the hydrogenation behaviours, crystal structure and bonding interactions with hydrogen. The LaMgSn structure is significantly expanded as compared to the earlier studied isotypic LaNiSn H storage material (volume expansion of 23%), as a result of a substitution of the smaller Ni atoms by much larger Mg atoms. This significantly affects the chemistry of the interaction of the intermetallic compound with hydrogen because a transition metal, Ni, in replaced by an active hydride-forming metal, Mg. The work involved computational studies of the electronic structure of the intermetallic compound and its hydride, and experimental studies of the hydrogenation behaviour and thermal stability of the formed hydride LaMgSnH, its structural characterisation by SR XRD and neutron powder diffraction, and Mössbauer spectroscopic studies of the stannide and its hydride. These studies showed that in the system LaMgSn-H2 a monohydride LaMgSnH is a thermodynamically favourable hydride composition. PDOS levels show that hydrogen and all constituting elemental metals, La, Mg and Sn, have peaks of electron density in the range between − 6 and − 4 eV indicating their hybridisation. The results show the hybridization of H atoms not only with bonded La and Mg atoms forming H-filled tetrahedra La3Mg, but also with Sn despite its atoms do not have bonding interactions with H. This explains the high stability of the metal substructure which does not disproportionate into the binary hydrides of La and Mg even when heated to 200 °C @ 20 bar H2, but instead forms an insertion type hydride. Formation of the monohydride LaMgSnH (Sp.gr. Pnma; a=8.1628(4); b= 4.5555(3); c= 9.2391(5) Å; V= 343.56(5) Å3) causes a small (1.26%) expansion of the unit cell volume compared to LaMgSn, and mainly proceeds along the [100] direction. Hydrogen absorption-desorption cycle results in a reversible formation of the initial compound LaMgSn, with the peak of hydrogen release occurring in vacuum at 355 °C, which is intermediate between the temperatures for the vacuum decomposition of the dihydrides MgH2 and LaH2. From the combined refinements of the Synchrotron (SR) XRD and Neutron Powder Diffraction (NPD) data, deuterium atoms completely and in an ordered way fill a half of the available La3Mg interstitial sites with metal-H/D distances of Mg-D= 2.026 Å; La-D= 2.381 and 2.502 Å. The occupied La3Mg sites are smaller in size than the vacant Mg3La tetrahedra. Sn and D exhibit a nonbonding interaction with the closest Sn-D separation of 3.033 Å. 119Sn Mössbauer spectra of LaMgSn and LaMgSnH show isomer shifts of 1.98(2) and 1.99(1) mm/s which are typical for the chemically similar stannides.","DFT studies; LaMgSn stannide; Metal hydrides; Mössbauer spectroscopy; Neutron diffraction","en","journal article","","","","","","","","","","","RID/TS/Technici Pool","","",""
"uuid:dbe6227b-ce75-4c53-a415-cdc313d10d66","http://resolver.tudelft.nl/uuid:dbe6227b-ce75-4c53-a415-cdc313d10d66","Stroke patients’ motivation for home-based upper extremity rehabilitation with eHealth tools","Langerak, A.J. (Erasmus MC); D'Olivo, P. (TU Delft Design Aesthetics); Thijm, O. S.A. (Erasmus MC; Leiden University Medical Center); Regterschot, G.R.H. (Erasmus MC); Meskers, C. G.M. (Amsterdam UMC); Rozendaal, M.C. (TU Delft Human Information Communication Design); Visch, V.T. (TU Delft Design Aesthetics); Bussmann, J.B.J. (Erasmus MC)","","2024","Purpose: eHealth-based exercise therapies were developed to increase stroke patients’ adherence to home-based motor rehabilitation. However, these eHealth tools face a rapid decrease in use after a couple of weeks. This study investigates stroke patients’ motivation for home-based upper extremity rehabilitation with eHealth tools and their relation with Basic Psychological Needs. Materials and methods: This is a qualitative study using thematic analysis. We conducted semi-structured interviews with stroke patients with upper extremity motor impairments, who were discharged home from a rehabilitation centre, after they interacted with a novel eHealth coach demonstrator in their homes for five consecutive days. Results: We included ten stroke patients. Thematic analysis resulted in eight themes for home-based rehabilitation motivation: Curiosity, Rationale, Choice, Optimal challenge, Reference, Encouragement, Social Support and Trustworthiness. Those themes are embedded into three Basic Psychological Needs: “Autonomy”, “Competence”, and “Relatedness”. Conclusion: Eight motivational themes related to the three Basic Psychological Needs describe stroke patients’ motivation for home-based upper extremity rehabilitation. We recommend considering those themes when developing a home-based eHealth intervention for stroke patients to increase the alignment of eHealth tools to the patient’s needs and reduce motivational decreases in home-based rehabilitation.","adherence; eHealth; motivation; rehabilitation; Stroke; upper extremity","en","journal article","","","","","","","","","","","Design Aesthetics","","",""
"uuid:6ef66de3-b3b1-4f9f-bed0-14301f753645","http://resolver.tudelft.nl/uuid:6ef66de3-b3b1-4f9f-bed0-14301f753645","Pointing Calibration of GroundBIRD Telescope Using Moon Observation Data","Sueno, Y. (Graduate School of Science); Baselmans, J.J.A. (TU Delft Tera-Hertz Sensing; SRON Netherlands Institute for Space Research); Coppens, A. (SRON Netherlands Institute for Space Research); Génova-Santos, R. T. (Instituto de Astrofísica de Canarias; Universidad de la Laguna); Hattori, M. (Tohoku University); Karatsu, K. (SRON Netherlands Institute for Space Research); Lee, K. (Korea University; Student TU Delft); Suzuki, J. (Graduate School of Science); Thoen, David (SRON Netherlands Institute for Space Research)","","2024","Understanding telescope pointing (i.e. line of sight) is important for observing the cosmic microwave background (CMB) and astronomical objects. The Moon is a candidate astronomical source for pointing calibration. Although the visible size of the Moon (30`) is larger than that of the planets, we can frequently observe the Moon once a month with a high signal-to-noise ratio. We developed a method for performing pointing calibration using observational data from the Moon. We considered the tilts of the telescope axes as well as the encoder and collimation offsets for pointing calibration. In addition, we evaluated the effects of the nonuniformity of the brightness temperature of the Moon, which is a dominant systematic error. As a result, we successfully achieved a pointing accuracy of 3.3`. This is one order of magnitude smaller than an angular resolution of 36`. This level of accuracy competes with past achievements in other ground-based CMB experiments using observational data from the planets.","","en","journal article","","","","","","","","","","","Tera-Hertz Sensing","","",""
"uuid:b1684432-c423-4ba8-adcb-41ad5fe1bfb0","http://resolver.tudelft.nl/uuid:b1684432-c423-4ba8-adcb-41ad5fe1bfb0","Time to failure analysis of wood adhesives: a non-linear approach based on chemical reaction kinetics","van de Kuilen, J.W.G. (TU Delft Bio-based Structures & Materials; Technische Universität München); Clerc, G. (Swiss Wood Solutions AG); Mosleh, Yasmine (TU Delft Bio-based Structures & Materials); Gard, W.F. (TU Delft Bio-based Structures & Materials); Richter, K. (Technische Universität München)","","2024","Similar to wood, adhesives may exhibit duration of load effects. When loaded for longer periods of time, damage processes in the material may develop, eventually leading to failure. From wood research it is known that load level, temperature and relative humidity have an important influence on this behaviour. In general, higher stress levels, temperatures, and moisture content will lead to shorter times to failure and these effects may be more pronounced in loading directions such as shear or tension perpendicular to the grain. It is shown that the reaction kinetics based approach for damage accumulation effects in polyurethane based adhesives can be described using the same non-linear damage accumulation expression as used for wood. The relationship between the time to failure and load-level as influenced by for instance temperature is determined for lap joints, immersed in hot water with temperature of 60oC and 90oC, and at load levels varying between 30 and 90% of the mean short term shear strength.
It is shown that a non-linear damage accumulation expression as used for wood, can also be used for damage accumulation effects in melamine-urea-formaldehyde adhesives. The relationship between the time to failure and load-level as influenced by temperature is determined for beech lap joints loaded in tensile shear. The specimens have been immersed in hot water with temperatures of 60oC and 90oC respectively, and at load levels varying between 30 and 90% of the mean short term shear strength.","adhesive; wood; reaction kinetic; failure analysis; reaction kinetics; temperature effect","en","journal article","","","","","","","","","","","Bio-based Structures & Materials","","",""
"uuid:127b7fc0-cb2b-4691-b97f-430d576bf661","http://resolver.tudelft.nl/uuid:127b7fc0-cb2b-4691-b97f-430d576bf661","Analytical treatments of time-fractional seventh-order nonlinear equations via Elzaki transform","Ali, Liaqat (Southern University of Science and Technology; Zhejiang University); Zou, Guang (Southern University of Science and Technology); Li, Na (Southern University of Science and Technology); Mehmood, Kashif (Zhejiang University); Fang, P. (TU Delft Transport Engineering and Logistics); Khan, Adnan (Abdul Wali Khan University Mardan)","","2024","In this article, we’ll show how to solve the time-fractional seventh-order Lax’s Korteweg–de Vries and Kaup–Kupershmidt equations analytically using the homotopy perturbation approach, the Adomian decomposition method, and the Elzaki transformation. The KdV equation is a general integrable equation with an inverse scattering transform-based solution that arises in a variety of physical applications, including surface water waves, internal waves in a density stratified fluid, plasma waves, Rossby waves, and magma flow. Fractional derivative is described in the Caputo sense. The solutions to fractional partial differential equation is computed using convergent series. The numerical computations and graphical representations of the analytical results obtained using the homotopy perturbation and decomposition techniques. Moreover, plots that are simple to grasp are used to compare the integer order and fractional-order solutions. After only a few iterations, we may easily obtain numerical results that provide us better approximations. The exact solutions and the derived solutions were observed to be very similar. The suggested methods have also acquired the highest level of accuracy. The most prevalent and convergent techniques for resolving nonlinear fractional-order partial differential issues are the applied techniques.","26A33; 34A25; 35A20; 35Q53; Analytical techniques; Caputo operator; Elzaki Transform; Kaup–Kupershmidt (KK) equation; Lax’s Korteweg–de Vries equation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-17","","","Transport Engineering and Logistics","","",""
"uuid:dd1db052-8834-4c07-af2b-3fe1bdeb64a6","http://resolver.tudelft.nl/uuid:dd1db052-8834-4c07-af2b-3fe1bdeb64a6","Unraveling the hydrogen sulfide aging mechanism on electrical-thermal–mechanical property degradation of sintered nanocopper interconnects used in power electronics packaging","Chen, Wei (Fudan University); Liu, Xu (Fudan University); Hu, D. (TU Delft Electronic Components, Technology and Materials); Liu, X. (TU Delft Electronic Components, Technology and Materials); Zhu, Xi (Fudan University; Research Institute of Fudan University, Ningbo); Fan, Xuejun (Lamar University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University; Research Institute of Fudan University, Ningbo)","","2024","During operation in environments containing hydrogen sulfide (H2S), such as in offshore and coastal environments, sintered nanoCu in power electronics is susceptible to degradation caused by corrosion. In this study, experimental and molecular dynamics (MD) simulation analyses were conducted to investigate the evolution and mechanism of H2S-induced corrosion of sintered nanoCu, and bulk Cu was used as the reference. The following results are obtained: (1) Both sintered nanoCu and bulk Cu reacted with O2 prior to reacting with H2S, forming Cu2O, Cu2S, CuO, and CuS. In addition, sintered nanoCu exhibited more severe corrosion. (2) For both sintered nanoCu and bulk Cu, H2S-induced corrosion resulted in the deterioration of electrical, thermal, and mechanical properties, and sintered nanoCu experienced a greater extent of deterioration. (3) As was ascertained through Reactive Force Field (ReaxFF) MD simulations, the penetration of H2S and O2 combined with the upward migration of Cu resulted in the formation of a corrosion film. In addition, compared to bulk Cu, the H2S and O2 penetration in the sintered nanoCu structure was observed to occur to a greater depth, accounting for the more pronounced performance degradation.","HS corrosion; Performance degradation; ReaxFF; Shear strength; Sintered nanocopper","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:97cfad13-ee97-4ec2-b8e8-ea029adde6bf","http://resolver.tudelft.nl/uuid:97cfad13-ee97-4ec2-b8e8-ea029adde6bf","Interdependence in rare earth element supply between China and the United States helps stabilize global supply chains","Chen, Wei (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Eckelman, Matthew J. (Northeastern University); Sprecher, B. (TU Delft Design for Sustainability); Chen, Wei (Chinese Academy of Sciences; University of Science and Technology of China); Wang, Peng (Chinese Academy of Sciences; University of Chinese Academy of Sciences)","","2024","Rare earth elements (REEs) are vital to the development of low-carbon technologies. There are rising concerns in the United States and elsewhere about REE supply chain stability and risks given the unvalidated perception in the heavy reliance of China, by far the largest REE supplier. However, the relationship between key countries at different stages of global REE supply chains remains unclear. Here, we use a dynamic flow analysis to explore supply dependence between the United States and China by tracing REE flows from mineral mining to market between 2000 and 2022. Our results indicate complementary and cooperative US–China interactions, especially after 2018 when the United States became a net exporter of REE and China's largest supplier, and China became the largest importer of the US REEs and manufacturer of REE-enabled low-carbon technologies. This intensifying interdependence stabilizes REE supply chains and highlights the importance of cooperative REE trade networks.","critical raw materials; material flow analysis; rare earth elements; sustainable development; US–China cooperation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Design for Sustainability","","",""
"uuid:1a534a77-ee67-4431-819a-1a50fe7cdd70","http://resolver.tudelft.nl/uuid:1a534a77-ee67-4431-819a-1a50fe7cdd70","Charge carrier trapping management in Bi3+ and lanthanides doped Li(Sc,Lu)GeO4 for x-ray imaging, anti-counterfeiting, and force recording","Lyu, Tianshuai (Huaqiao University); Dorenbos, P. (TU Delft RST/Luminescence Materials)","","2024","Discovering energy storage materials with rationally controlled trapping and de-trapping of electrons and holes upon x-rays, UV-light, or mechanical force stimulation is challenging. Such materials enable promising applications in various fields, for instance in multimode anti-counterfeiting, x-ray imaging, and non-real-time force recording. In this work, photoluminescence spectroscopy, the refined chemical shift model, and thermoluminescence studies will be combined to establish the vacuum referred binding energy (VRBE) diagrams for the LiSc1-xLuxGeO4 family of compounds containing the energy level locations of Bi2+, Bi3+, and the lanthanides. The established VRBE diagrams are used to rationally develop Bi3+ and lanthanides doped LiSc1-xLuxGeO4 storage phosphors and to understand trapping and de-trapping processes of charge carriers with various physical excitation means. The thermoluminescence intensity of x-ray irradiated LiSc0.25Lu0.75GeO4:0.001Bi3+,0.001Eu3+ is about two times higher than that of the state-of-the-art x-ray storage phosphor BaFBr(I):Eu2+. Particularly, a force induced charge carrier storage phenomenon appears in Eu3+ co-doped LiSc1-xLuxGeO4. Proof-of-concept non-real-time force recording, anti-counterfeiting, and x-ray imaging applications will be demonstrated. This work not only deepens our understanding of the capturing and de-trapping processes of electrons and holes with various physical excitation sources, but can also trigger scientists to rationally discover new storage phosphors by exploiting the VRBEs of bismuth and lanthanide levels.","","en","journal article","","","","","","","","2024-08-21","","","RST/Luminescence Materials","","",""
"uuid:5c00b6ee-4dc8-452b-865a-ae69ae187aa5","http://resolver.tudelft.nl/uuid:5c00b6ee-4dc8-452b-865a-ae69ae187aa5","Assessing the feasibility of CO2 removal strategies in achieving climate-neutral power systems: Insights from biomass, CO2 capture, and direct air capture in Europe","Béres, Rebeka (University Medical Center Groningen); Junginger, Martin (Universiteit Utrecht); van den Broek, M.A. (TU Delft Energie and Industrie)","","2024","To achieve the European Union's goal of climate neutrality by 2050, negative emissions may be required to compensate for emissions exceeding allocated carbon budgets. Therefore, carbon removal technologies such as bioenergy with carbon capture (BECCS) and direct air capture (DAC) may need to play a pivotal role in the power system. To design carbon removal strategies, more insights are needed into the impact of sustainable biomass availability and the feasibility of carbon capture and storage (CCS), including the expensive and energy-intensive DAC on achieving net-zero and net-negative targets. Therefore, in this study the European power system in 2050 is modelled at an hourly resolution in the cost-minimization PLEXOS modelling platform. Three climate-neutral scenarios with targets of 0, -1, and -3.9 Mt CO2/year (which agree with varying levels of climate justice) are assessed for different biomass levels, and CCS availability. Findings under baseline assumptions reveal that in a climate-neutral power system with biomass and CCS options, it is cost-effective to complement variable renewable energy with a mix of combined cycle natural gas turbines (CCNGT) for flexibility and BECCS as base load to compensate for the CO2 emissions from natural gas and additional carbon removal in the net-negative scenarios. The role of these technologies becomes more prominent, with -3.9 GtCO2/year target. Limited biomass availability necessitates additional 0.4–4 GtCO2/year DAC, 10–50 GW CCNGT with CCS, and 10–50 GW nuclear. Excluding biomass doubles system costs and increases reliance on nuclear energy up to 300 TWh/year. The absence of CCS increases costs by 78%, emphasizing significant investments in bioenergy, nuclear power, hydrogen storage, and biogas. Sensitivity analysis and limitations of the study are fully discussed.","Bioenergy with carbon capture; Direct air capture; European green deal; Negative emissions; Power system modelling","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:bd02c390-2e97-4ff5-89de-fdcd16a3615b","http://resolver.tudelft.nl/uuid:bd02c390-2e97-4ff5-89de-fdcd16a3615b","‘‘It’s okay because I’m just driving’’: an exploration of self-reported mobile phone use among Mexican drivers","Useche, Sergio A. (Universidad de Valencia (ICMol)); Alonso, Francisco (Universidad de Valencia (ICMol)); Faus, Mireia (Universidad de Valencia (ICMol)); Trejo, Arturo Cervantes (Anahuac University); Castaneda, Isaac (Anahuac University); Oviedo-Trespalacios, O. (TU Delft Safety and Security Science)","","2024","Introduction. Technological advancements have the potential to enhance people’s quality of life, but their misuse can have a detrimental impact on safety. A notable example is the escalating issue of distracted driving resulting from the use of mobile phones behind the wheel, leading to severe crashes and injuries. Despite these concerns, both drivers’ usage patterns and their risk-related associations remain scarcely documented in Mexico. Therefore, this descriptive study aimed to examine the mobile phone usage of Mexican drivers, its relationships to risk awareness and near-miss/crash involvement, and the self-reported underlying reasons for this behavior. Methods. This cross-sectional study utilized a sample of 1,353 licensed Mexican drivers who took part in a nationwide series of interviews regarding their onboard phone use settings. Results. A significant percentage of drivers (96.8%) recognize using a mobile phone while driving as high-risk behavior. However, only 7.4% reported completely avoiding its use while driving, with 22.4% identified as high-frequency users. Frequency was also found positively associated with the self-reported rate of near-misses and crashes. Furthermore, qualitative data analysis highlights the emergence of a ‘sense of urgency’ to attend to phone-related tasks in response to daily demands and life dynamics, offering a potential explanation for this behavior. Conclusion. The results of this study suggest common patterns of onboard mobile use among Mexican drivers concerning driving situations and associated risks. This underscores the need for increased efforts to discourage onboard phone use in the country.","Cell phone; Driving; Habits; Road distractions; Texting","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:e4066dd5-6409-47dd-8176-f2b9c75c0632","http://resolver.tudelft.nl/uuid:e4066dd5-6409-47dd-8176-f2b9c75c0632","When does infrastructure hybridisation outperform centralised infrastructure paradigms? – Exploring economic and hydraulic impacts of decentralised urban wastewater system expansion","Duque, Natalia (Swiss Federal Institute of Aquatic Science and Technology; ETH Zürich); Scholten, L. (TU Delft Policy Analysis); Maurer, Max (Swiss Federal Institute of Aquatic Science and Technology; ETH Zürich)","","2024","We explore the dynamics of centralised and decentralised wastewater infrastructure across various scenarios and introduce novel insights into their performance regarding structural vulnerability, hydraulic capacity, and costs. This study determines circumstances under which infrastructure hybridisation outperforms traditional centralised infrastructure paradigms. We combined system analysis to map out the modelling problem with the model-based exploration of the transition space using the novel TURN-Sewers model. System diagramming was used to identify the parameters or combinations of parameters that significantly influence the performance indicators being assessed. This allowed the creation of relevant simulation scenarios to identify circumstances where a decentralised sewer system could outperform a centralised one. TURN-Sewers was applied to model the infrastructure maintenance and generation of new infrastructure over 20 years for a municipality on the Swiss Plateau, considering a population growth rate of 0.03 a−1. Results show that decentralisation in expansion areas with higher densification can outperform the hydraulic performance and structural vulnerability of expanding centralised sanitary wastewater infrastructure. Decentralised systems can also offer economic advantages when capital expenditure costs for small-scale wastewater treatment plants are significantly reduced compared to current costs, particularly at higher discount rates, e.g. reaping effects of economies of scale. The findings of this study emphasise the potential of transition pathways towards decentralisation in urban water infrastructures and the value of models that allow the exploration of this transition space.","Performance assessment; System diagramming; Transition planning; Urban drainage; Wastewater infrastructure","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:2f0f4ac3-66de-45cb-83c0-2a258fdd634a","http://resolver.tudelft.nl/uuid:2f0f4ac3-66de-45cb-83c0-2a258fdd634a","Assessment criteria for inter-organizational collaboration in interconnected infrastructure projects","Rikhtegarnezami, M. (TU Delft Integral Design & Management); de Bruijne, M.L.C. (TU Delft Organisation & Governance); Hertogh, M.J.C.M. (TU Delft Integral Design & Management); Bakker, H.L.M. (TU Delft Integral Design & Management)","","2024","Purpose: Societies depend on interconnected infrastructures that are becoming more complex over the years. Multi-disciplinary knowledge and skills are essential to develop modern infrastructures, requiring close collaboration of various infrastructure owners. To effectively manage and improve inter-organizational collaboration (IOC) in infrastructure construction projects, collaboration status should be assessed continually. This study identifies the assessment criteria, forming the foundation of a tool for assessing the status of IOC in interconnected infrastructure projects.
Design/methodology/approach: A systematic literature study and in-depth semi-structured interviews with practitioners in interconnected infrastructure construction projects in the Netherlands are performed to identify the criteria for assessing the status of IOC in infrastructure construction projects, based on which an assessment tool is developed.
Findings: The identified assessment criteria through the literature and the practitioner’s perspectives results in the designing and development of a collaboration assessment tool. The assessment tool consists of 12 criteria and 36 sub-criteria from three different categories of collaborative capacity: individual, relational, and organizational.
Originality/value: The assessment tool enables practitioners to monitor the status of IOC between infrastructure owners and assists them in making informed decisions to enhance collaboration. The assessment tool provides the opportunity to assess and analyze the status of collaboration based on three categories (i.e., individual, relational, and organizational).","Assessment tool; Construction industry; Horizontal collaboration; Inter-organizational collaboration; Interconnected infrastructure","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:3a14246a-ee80-4335-9458-5695493ac77c","http://resolver.tudelft.nl/uuid:3a14246a-ee80-4335-9458-5695493ac77c","Cultural Heritage as an Inspiration for Placemaking in the Historic City: A Transversal Approach","García-Esparza, Juan A. (Universitat Jaume I); Hein, C.M. (TU Delft History, Form & Aesthetics); Rogac Mijatovic, Ljiljana (University of Arts in Belgrade); Negru, Mircea (Spiru Haret University)","Smaniotto Costa, Carlos (editor); Fathi, Mastoureh (editor); García-Esparza, Juan A. (editor); Djukic, Aleksandra (editor); Horan, Conor (editor); Rotondo, Francesco (editor)","2024","Many European cities are in crisis since most of them are struggling to socially and culturally move forward from the historic and recreational values that made them of interest to the global visitor. In 2011, the United Nations Educational, Scientific and Cultural Organization (UNESCO) started assessing new forms of placemaking in the historic city through the UNESCO Historic Urban Landscape Approach. The same year, the International Council on Monuments and Sites (ICOMOS) highlighted the importance of developing innovative and transversal approaches to examine cultural development in historic human settlements. Within this context, this chapter analyses placemaking in four European historic cities. Transversal approaches on how relational dynamics impact on the historic context will be scrutinized from the realm of the site-specific arts in the city of Belgrade (Serbia), for archaeology the case of analysis is in Bucharest (Romania), for architecture the context is Ávila (Spain) and for urban planning it is Hamburg (Germany). This transversal approach involves using different disciplines to comprehend placemaking from a polyhedral point of view. Therefore, it brings together complementary forms of heritage appropriation – including the construction of the heritage concept over time – methods and strategies that help integrate cultural expressions, practices and products as potential relational dynamics. To do so, we will define stakeholders such as minorities, communities and powerful entities and target groups. Methodologically, approaches will deepen the understanding of phenomenological, dynamic-relational and contextual notions of placemaking that help clarify how historic cities, tools and communities are all interconnected. The discussion will establish parallelisms between the experiences to clarify the implications of placemaking according to the field of approach and the prospects for those places. Cultural expressions and heritage regulation can provide new forms of appropriation and integration in permanent scenarios of the past. Accordingly, contemporary mutable relationships between places and society are at stake in the context of urban planning and the UNESCO Historic Urban Landscape Approach and in defining the future of historic cities. In conclusion, we point towards (1) imagining how placemaking and cultural heritage serve to delineate new forms of heritage-making in the historic city, and (2) to what extent this requires defining ethical forms of culture-based placemaking practices.","cultural heritage; historic city; mutable places; heritage futures","en","book chapter","Brill","","","","","","","","","","History, Form & Aesthetics","","",""
"uuid:c13dd1e6-1704-4f5b-9b45-95de34eb7ef2","http://resolver.tudelft.nl/uuid:c13dd1e6-1704-4f5b-9b45-95de34eb7ef2","Integrating simulation and measurement techniques to model outdoor noise and heat in airport neighbourhoods with varying urban geometries","Wuite, F.G.E. (TU Delft Environmental & Climate Design; TU Delft Amsterdam Institute for Advanced Metropolitan Solutions); Peng, Zhikai (TU Delft Environmental & Climate Design; TU Delft Amsterdam Institute for Advanced Metropolitan Solutions); Kim, K.J. (TU Delft Environmental & Climate Design); Lugten, M.C. (TU Delft Environmental & Climate Design; TU Delft Amsterdam Institute for Advanced Metropolitan Solutions); Tenpierik, M.J. (TU Delft Environmental & Climate Design)","","2024","This study aims to evaluate the impact of different urban building geometries (six courtyards, two canyons, two slabs) on heat mitigation and aircraft noise attenuation, in order to support an evidence-based retrofit plan for future airport neighborhoods. Using ’Pachyderm + ENVI-met simulations + field measurements’, we found that the slanted-roof, low-rise courtyard exhibited optimal acoustic-thermal performance (SPLmin = 71.1 dB(A), σU T CI < 5 ◦C), while the mid-rise canyon demonstrated limited performance (SPLmin = 93.4 dB(A), σU T CI > 10 ◦C). These findings were observed under averaged boundary conditions of a 140 dB(A) aircraft sound source and a diurnal MRT range of 60 ◦C on a heatwave day in July 2022.","noise and heat; parametric design; airport neighbourhood; courtyard; outdoor comfort","en","conference paper","IBPSA","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-13","","Amsterdam Institute for Advanced Metropolitan Solutions","Environmental & Climate Design","","",""
"uuid:22163f75-f825-4257-9cf4-7f1c479da4ad","http://resolver.tudelft.nl/uuid:22163f75-f825-4257-9cf4-7f1c479da4ad","Response of Late-Eocene warmth to incipient glaciation on Antarctica","Vermeulen, D.H.A. (TU Delft Environmental Fluid Mechanics); Baatsen, Michiel (Universiteit Utrecht); Heydt, Anna von der (Universiteit Utrecht)","","2024","The Eocene-Oligocene Transition is marked by a sudden δ18O excursion occurring in two distinct phases: a precursor event at 34.15±0.04 Ma and the Earliest Oligocene oxygen Isotope Step at 33.65±0.04 Ma. These events signal a shift from the warm Late-Eocene greenhouse climate to cooler conditions, with temperature decreases of 3-5 °C, and the emergence of the first continent-wide Antarctic Ice Sheet (AIS). Despite clear evidence from proxy data, general circulation models (GCMs) struggle to replicate this Antarctic transition accurately, failing to capture the shift from warm, ice-free to cold, glaciated conditions. Even with unrealistically low pCO2 levels, Late-Eocene Antarctic summers in GCMs remain too warm and moist for snow or ice to survive. This study evaluates CESM1.0.5 simulations conducted by Baatsen et al. (2020), using a 38 Ma geo- and topographical reconstruction, considering different radiative (4 pre-industrial carbon levels (PIC) and 2 PIC) and orbital (present-day insolation and low Antarctic summer insolation) forcings. The climate is found to be highly seasonal, characterised by hot and wet summers and cold and dry winters. While reduced radiative and summer insolation forcing weaken this seasonality, the persistent atmospheric circulation still impedes ice sheet growth by limiting summer snow survival. For that reason, a new simulation is conducted with regional, moderately-sized ice sheets imposed on the continent, in order to investigate their stability and their influence on the atmospheric circulation. These ice sheets demonstrate self-sustaining and even expansion potential under 2 PIC and low summer insolation conditions. However, correlating resulting temperature and precipitation patterns with proxy data proves challenging, given the absence of terrestrial proxies. Extended simulations with coupled GCM-ISM models are therefore recommended, allowing for more dynamic atmosphere-ice-ocean-vegetation feedback mechanisms and dynamic radiative and orbital forcing.","","en","abstract","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:6a2d6ba5-1eaf-4b41-83f8-1ae45f976896","http://resolver.tudelft.nl/uuid:6a2d6ba5-1eaf-4b41-83f8-1ae45f976896","Impact of geometrical resolution on long-term climate-based daylight metrics","Forouzandeh Shahraki, N. (TU Delft Environmental & Climate Design); Brembilla, E. (TU Delft Environmental & Climate Design); Stoter, J.E. (TU Delft Urban Data Science); Nan, L. (TU Delft Urban Data Science)","","2024","3D modeling of indoor spaces is a prerequisite for daylight simulation, and the accuracy of the 3D models has a significant impact on the simulation. The goal of this study was to quantify the errors caused by modeling indoor spaces at different accuracy levels to find the optimal balance between the reliability of the results and labor investment. For this purpose, we introduce a level of detail (LOD) concept for indoor spaces based on the size of non-permanent indoor objects by inclusion and exclusion from the simulation scene. The errors corresponding to models with low accuracies are measured by climate-based simulation using an improved two-phase method. Our results show that inaccurate modeling of indoor spaces causes between 10-70% error in TAI with 25% median across all spaces.","daylight; blinds automated control; complex fenestration systems; radiance matrix methods","en","conference paper","IBPSA","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-13","","","Environmental & Climate Design","","",""
"uuid:7bc0145f-3e4b-4947-9617-9f71462394be","http://resolver.tudelft.nl/uuid:7bc0145f-3e4b-4947-9617-9f71462394be","A 0D Model for the Comparative Analysis of Hydrogen Carriers in Ship’s Integrated Energy Systems","Van Rheenen, E.S. (TU Delft Ship Design, Production and Operations); Padding, J.T. (TU Delft Complex Fluid Processing); Visser, K. (TU Delft Ship Design, Production and Operations)","","2024","Hydrogen carriers are attractive alternative fuels for the shipping sectors. They are zero-emission, have high energy densities, and are safe, available, and easy to handle. Sodium borohydride, potassium borohydride, dibenzyltoluene, n-ethylcarbazole, and ammoniaborane are interesting hydrogen carriers, with high theoretical energy densities. The exact energy density of these hydrogen carriers depends on the integration of heat and mass with the energy converters. This combination defines the energy efficiency and, thus, the energy density of the system. Using a 0D model, we combined the five carriers with two types of fuel cells (PEM and SOFC), an internal combustion engine and a gas turbine. This resulted in 20 combinations. Despite the limitations of the 0D model and the occasional difficulty of validating input values, this model still produces exciting findings, which are valuable for further research. For the dehydrogenation of both dibenzyltoluene and n-ethylcarbazole, an external hydrogen burner is required if no waste heat resources from the integrated system are available. For the borohydrides, on the other hand, energy integration is essential for reducing cooling power. Dehydrogenation produces substantial energy, but only a fraction of this energy can be used for internal preheating. Dehydrogenation of ammoniaborane produces less energy. Among all hydrogen carriers, both ammoniaborane and sodium borohydride provide energy densities comparable to that of marine diesel oil. In particular, ammoniaborane possesses a remarkably high energy density. Thus, we conclude, that hydrogen carriers are attractive alternative fuels that deserve more attention, including their potential performance for hydrogen imports.
−1 in vitamin-free synthetic medium. This growth rate was only 17 % lower than that of a congenic reference strain in vitamin-supplemented medium. Physiological parameters of the engineered vitamin-independent strain in aerobic glucose-limited chemostat cultures (dilution rate 0.10 h−1) grown on vitamin-free synthetic medium were similar to those of similar cultures of the parental strain grown on vitamin-supplemented medium. Transcriptome analysis revealed only few differences in gene expression between these cultures, which primarily involved genes with roles in Class-B vitamin metabolism. These results pave the way for development of fast-growing vitamin-independent industrial strains of S. cerevisiae.","","en","journal article","","","","","","","","","","BT/Biotechnologie","BT/Industriele Microbiologie","","",""
"uuid:45496b8b-2ff4-4c71-a854-c027d4532cb7","http://resolver.tudelft.nl/uuid:45496b8b-2ff4-4c71-a854-c027d4532cb7","Visualizing greener cities","Metze, T.A.P. (TU Delft Organisation & Governance); Rojas-Padilla, Eduardo (Wageningen University & Research)","","2024","To realize sustainability transitions, there is a need for broad societal support. A study now shows that images can be influential in building that support, even in the case of policy decisions to invest in greener urban transportation, which more sceptical citizens would typically not endorse.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-23","","","Organisation & Governance","","",""
"uuid:58070867-ed09-4481-ad80-f5430929205e","http://resolver.tudelft.nl/uuid:58070867-ed09-4481-ad80-f5430929205e","To Share or Not to Share: Understanding and Modeling Individual Disclosure Preferences in Recommender Systems for the Workplace","Musick, Geoff (Clemson University); Duan, Wen (Clemson University); Najafian, S. (TU Delft Web Information Systems); Sengupta, Subhasree (Clemson University); Flathmann, Christopher (Clemson University); Knijnenburg, Bart (Clemson University); McNeese, Nathan (Clemson University)","","2024","Newly-formed teams often encounter the challenge of members coming together to collaborate on a project without prior knowledge of each other’s working and communication styles. This lack of familiarity can lead to conflicts and misunderstandings, hindering effective teamwork. Derived from research in social recommender systems, team recommender systems have shown the ability to address this challenge by providing personality-derived recommendations that help individuals interact with teammates with differing personalities. However, such an approach raises privacy concerns as to whether teammates would be willing to disclose such personal information with their team. Using a vignette survey conducted via a research platform that hosts a team recommender system, this study found that context and individual differences significantly impact disclosure preferences related to team recommender systems. Specifically, when working in interdependent teams where success required collective performance, participants were more likely to disclose personality information related to Emotionality and Extraversion unconditionally. Drawing on these findings, this study created and evaluated a machine learning model to predict disclosure preferences based on group context and individual differences, which can help tailor privacy considerations in team recommender systems prior to interaction.","Additional Key Words and Phrases: Group recommender systems; Individual difference; Privacy; Teamwork","en","journal article","","","","","","","","","","","Web Information Systems","","",""
"uuid:66d406bf-c98d-43de-bc64-0053546ef45d","http://resolver.tudelft.nl/uuid:66d406bf-c98d-43de-bc64-0053546ef45d","Target-oriented acquisition geometry design based on full-wavefield migration","Revelo Obando, B.A. (TU Delft Applied Geophysics and Petrophysics); Blacquière, G. (TU Delft Applied Geophysics and Petrophysics)","","2024","The ultimate goal of survey design is to find the acquisition parameters that enable acquiring high-quality data suitable for optimal imaging, while fulfilling budget, health, safety, and environmental constraints. We develop a target-oriented acquisition design algorithm based on full-wavefield migration. The algorithm optimizes a receiver density function that indicates the number of receivers per unit area required for obtaining the best possible image quality. The method makes use of available seismic data to create a reference model that is included in our objective function. To make the design target oriented, the objective function is multiplied with a mask that gives more weight to the target areas of interest. The results of the 2D and 3D implementations indicate an optimized receiver density function with higher values at the zones where more data are needed for improving image quality. The corresponding receiver geometries have more receivers placed in these areas. We validate the results by computing the images of the target zone using uniform and optimized geometries. The use of the latter indicates an improvement in the image quality at the target zone. In addition, we compute the number of receivers required for achieving a certain signal-to-noise ratio after imaging based on the optimized receiver density function.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-26","","","Applied Geophysics and Petrophysics","","",""
"uuid:fbf7b930-a863-456a-88e6-f157d09aa141","http://resolver.tudelft.nl/uuid:fbf7b930-a863-456a-88e6-f157d09aa141","TOSCA – an open-source, finite-volume, large-eddy simulation (LES) environment for wind farm flows","Stipa, S. (University of British Columbia); Ajay, Arjun (University of British Columbia); Allaerts, D.J.N. (TU Delft Wind Energy); Brinkerhoff, Joshua (University of British Columbia)","","2024","The growing number and growing size of wind energy projects coupled with the rapid growth in high-performance computing technology are driving researchers toward conducting large-scale simulations of the flow field surrounding entire wind farms. This requires highly parallel-efficient tools, given the large number of degrees of freedom involved in such simulations, and yields valuable insights into farm-scale physical phenomena, such as gravity wave interaction with the wind farm and farm–farm wake interactions. In the current study, we introduce the open-source, finite-volume, large-eddy simulation (LES) code TOSCA (Toolbox fOr Stratified Convective Atmospheres) and demonstrate its capabilities by simulating the flow around a finite-size wind farm immersed in a shallow, conventionally neutral boundary layer (CNBL), ultimately assessing gravity-wave-induced blockage effects. Turbulent inflow conditions are generated using a new hybrid off-line–concurrent-precursor method. Velocity is forced with a novel pressure controller that allows us to prescribe a desired average hub-height wind speed while avoiding inertial oscillations above the atmospheric boundary layer (ABL) caused by the Coriolis force, a known problem in wind farm LES studies. Moreover, to eliminate the dependency of the potential-temperature profile evolution on the code architecture observed in previous studies, we introduce a method that allows us to maintain the mean potential-temperature profile constant throughout the precursor simulation. Furthermore, we highlight that different codes do not predict the same velocity inside the boundary layer under geostrophic forcing owing to their intrinsically different numerical dissipation. The proposed methodology allows us to reduce such spread by ensuring that inflow conditions produced from different codes feature the same hub wind and thermal stratification, regardless of the adopted precursor run time. Finally, validation of actuator line and disk models, CNBL evolution, and velocity profiles inside a periodic wind farm is also presented to assess TOSCA’s ability to model large-scale wind farm flows accurately and with high parallel efficiency.","","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:9e2a881c-0238-4a37-ab2a-54d87d2a19dc","http://resolver.tudelft.nl/uuid:9e2a881c-0238-4a37-ab2a-54d87d2a19dc","Stability of dusty rings in protoplanetary discs","Chan, Kevin (Queen Mary University of London); Paardekooper, S. (TU Delft Planetary Exploration; Queen Mary University of London)","","2024","Dust rings in protoplanetary discs are often observed in thermal dust emission and could be fa v ourable environments for planet formation. While dust rings readily form in gas pressure maxima, their long-term stability is key to both their observability and potential to assist in planet formation. We investigate the stability of the dust ring generated by interactions of a protoplanetary disc with a Neptune-sized planet and consider its possible long-term evolution using the FARGO3D Multifluid code. We look at the onset of the Rossby Wave Instability (RWI) and compare how the addition of dust in a disc can alter the stability of the gas phase. We find that with the addition of dust, the rings generated by planet-disc interactions are more prone to RWI and can cause the gas phase to become unstable. The instability is shown to occur more easily for higher Stokes number dust, as it accumulates into a more narrow ring which triggers the RWI, while the initial dust fraction plays a more minor role in the stability properties. We show that the dusty RWI generates vortices that collect dust in their cores, which could be sites for further planetesimal formation. We conclude that the addition of dust can cause a ring in a protoplanetary disc to become more prone to instability leading to a different long-term evolution compared to gas-only simulations of the RWI.","hydrodynamics; methods: numerical; protoplanetary discs","en","journal article","","","","","","","","","","","Planetary Exploration","","",""
"uuid:fd4dad4b-495b-496a-83c4-8abd136499e3","http://resolver.tudelft.nl/uuid:fd4dad4b-495b-496a-83c4-8abd136499e3","Migration of low-mass planets in inviscid discs: the effect of radiation transport on the dynamical corotation torque","Ziampras, Alexandros (Queen Mary University of London); Nelson, Richard P. (Queen Mary University of London); Paardekooper, S. (TU Delft Planetary Exploration; Queen Mary University of London)","","2024","Low-mass planets migrate in the type-I regime. In the inviscid limit, the contrast between the vortensity trapped inside the planet's corotating region and the background disc vortensity leads to a dynamical corotation torque, which is thought to slow down inward migration. We investigate the effect of radiative cooling on low-mass planet migration using inviscid 2D hydrodynamical simulations. We find that cooling induces a baroclinic forcing on material U-turning near the planet, resulting in vortensity growth in the corotating region, which in turn weakens the dynamical corotation torque and leads to 2-3 × faster inw ard migration. This mechanism is most efficient when cooling acts on a time-scale similar to the U-turn time of material inside the corotating region, but is none the less rele v ant for a substantial radial range in a typical disc ( R ~5-50 au). As the planet migrates inwards, the contrast between the vortensity inside and outside the corotating region increases and partially regulates the effect of baroclinic forcing. As a secondary ef fect, we sho w that radiati ve damping can further weaken the vortensity barrier created by the planet's spiral shocks, supporting inward migration. Finally, we highlight that a self-consistent treatment of radiative diffusion as opposed to local cooling is critical in order to avoid overestimating the vortensity growth and the resulting migration rate.","hydrodynamics; methods: numerical; planet-disc interactions","en","journal article","","","","","","","","","","","Planetary Exploration","","",""
"uuid:447a3d63-20f2-4454-b59c-5494c5c4f671","http://resolver.tudelft.nl/uuid:447a3d63-20f2-4454-b59c-5494c5c4f671","Closing the genome of unculturable cable bacteria using a combined metagenomic assembly of long and short sequencing reads","Hiralal, Anwar (Universiteit Antwerpen); Geelhoed, Jeanine S. (Universiteit Antwerpen); Hidalgo-Martinez, Silvia (Universiteit Antwerpen); Smets, Bent (Universiteit Antwerpen); van Dijk, Jesper R. (Universiteit Antwerpen); Meysman, F.J.R. (TU Delft BT/Environmental Biotechnology; Universiteit Antwerpen)","","2024","Many environmentally relevant micro-organisms cannot be cultured, and even with the latest metagenomic approaches, achieving complete genomes for specific target organisms of interest remains a challenge. Cable bacteria provide a prominent example of a microbial ecosystem engineer that is currently unculturable. They occur in low abundance in natural sediments, but due to their capability for long-distance electron transport, they exert a disproportionately large impact on the biogeochemistry of their environment. Current available genomes of marine cable bacteria are highly fragmented and incomplete, hampering the elucidation of their unique electrogenic physiology. Here, we present a metagenomic pipeline that combines Nanopore long-read and Illumina short-read shotgun sequencing. Starting from a clonal enrichment of a cable bacterium, we recovered a circular metagenome-assembled genome (5.09 Mbp in size), which represents a novel cable bacterium species with the proposed name Candidatus Electrothrix scaldis. The closed genome contains 1109 novel identified genes, including key metabolic enzymes not previously described in incomplete genomes of cable bacteria. We examined in detail the factors leading to genome closure. Foremost, native, non-amplified long reads are crucial to resolve the many repetitive regions within the genome of cable bacteria, and by analysing the whole metagenomic assembly, we found that low strain diversity is key for achieving genome closure. The insights and approaches presented here could help achieve genome closure for other keystone micro-organisms present in complex environmental samples at low abundance.","cable bacteria; Candidatus Electrothrix scaldis; clonal enrichment; genome closure; hybrid sequencing; metagenomics","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:55dd445a-a888-4b92-b89f-0636cda80dec","http://resolver.tudelft.nl/uuid:55dd445a-a888-4b92-b89f-0636cda80dec","How do residents perceive energy-producing kites?: Comparing the community acceptance of an airborne wind energy system and a wind farm in Germany","Schmidt, H.S. (TU Delft Wind Energy); Leschinger, Valentin (University of Applied Science and Medical University; Martin-Luther-Universität Halle-Wittenberg); Müller, Florian J.Y. (University of Applied Science and Medical University); de Vries, G. (TU Delft Organisation & Governance); Renes, Reint Jan (Hogeschool van Amsterdam); Schmehl, R. (TU Delft Wind Energy); Hübner, Gundula (University of Applied Science and Medical University; Martin-Luther-Universität Halle-Wittenberg)","","2024","Airborne wind energy (AWE) is an emerging renewable energy technology that uses kites to harvest winds at higher altitudes than wind turbines. Understanding how residents experience a local AWE system (AWES) is important as the technology approaches commercialization. Such knowledge can help adjust the design and deployment of an AWES to fit locals' needs better, thereby decreasing the technology's burden on people. Although the AWE literature claims that the technology affects nature and residents less than wind turbines, empirical evidence has been lacking. This first community acceptance study recruited residents within a 3.5 km radius of an AWE test site in Northern Germany. Using structured questionnaires, 54 residents rated the AWES and the closest wind farm on visual, sound, safety, siting, environmental, and ecological aspects. Contrary to the literature's claims, residents assessed the noise, ecological, and safety impacts similarly for the AWES and the wind farm. Only visual impacts were rated better for the AWES (e.g., no shadows were perceived). Consistent with research on wind turbines, residents who rated the site operation as fairer and the developer as more transparent tended to have more positive attitudes towards the AWES and to experience less noise annoyance. Consequently, recommendations for the AWE industry and policymakers include mitigating technology impacts and implementing evidence-based strategies to ensure just and effective project development. The findings are limited to one specific AWES using soft-wing kites. Future research should assess community responses across regions and different types of AWESs to test the findings' generalizability.","Airborne wind energy; Wind turbine; Community acceptance; Attitude; Annoyance; Social impacts","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:e48feb37-7327-4c3f-99f5-8facdb84f093","http://resolver.tudelft.nl/uuid:e48feb37-7327-4c3f-99f5-8facdb84f093","Lateral-torsional buckling resistance of non-prismatic and prismatic mono-symmetric I-section steel beams based on stress utilization","Gomes, J. O. (Universidade de Coimbra; Universidade Federal de Minas Gerais); Simões da Silva, L. (Universidade de Coimbra); Tankova, T. (TU Delft Steel & Composite Structures); Carvalho, H. (Universidade Federal de Minas Gerais; Universidade de São Paulo); Filho, J. O. Ferreira (Universidade de Coimbra)","","2024","The lateral-torsional resistance of prismatic double-symmetric I-section beams is accurately predicted using a mechanically consistent Ayrton-Perry approach, combined with a calibrated generalized imperfection. The corresponding design formulation was recently adopted in the revised version of Eurocode 3. However, for prismatic mono-symmetric I-section beams, the General Case shall be used while for non-prismatic beams only the General Method is available. Both methods present a very large scatter and highly underestimate the lateral-torsional buckling resistance. This paper proposes an extension to the General Formulation for non-prismatic beams with arbitrary boundary conditions, partial lateral restraints, and arbitrary loading for mono-symmetric I-sections. Using an advanced numerical model calibrated with experimental test results, a large parametric study is undertaken, and its results are used to assess the available design methodologies and the proposed method. It is concluded that the General Formulation provides excellent safe-sided estimates of the LTB resistance, and it is confirmed the very poor performance of the General Case and the General Method.","Eurocode 3; General formulation; Mono-symmetric beams; Stability; Steel","en","journal article","","","","","","","","","","","Steel & Composite Structures","","",""
"uuid:ae1f97a8-00ea-49bd-80dc-7ff0a454b26e","http://resolver.tudelft.nl/uuid:ae1f97a8-00ea-49bd-80dc-7ff0a454b26e","Augmented reality for supporting the interaction between pedestrians and automated vehicles: an experimental outdoor study","Aleva, T.K. (Student TU Delft); Tabone, W. (TU Delft Human-Robot Interaction); Dodou, D. (TU Delft Medical Instruments & Bio-Inspired Technology); de Winter, J.C.F. (TU Delft Human-Robot Interaction)","","2024","Introduction: Communication from automated vehicles (AVs) to pedestrians using augmented reality (AR) could positively contribute to traffic safety. However, previous AR research for pedestrians was mainly conducted through online questionnaires or experiments in virtual environments instead of real ones.
Methods: In this study, 28 participants conducted trials outdoors with an approaching AV and were supported by four different AR interfaces. The AR experience was created by having participants wear a Varjo XR-3 headset with see-through functionality, with the AV and AR elements virtually overlaid onto the real environment. The AR interfaces were vehicle-locked (Planes on vehicle), world-locked (Fixed pedestrian lights, Virtual fence), or head-locked (Pedestrian lights HUD). Participants had to hold down a button when they felt it was safe to cross, and their opinions were obtained through rating scales, interviews, and a questionnaire.
Results: The results showed that participants had a subjective preference for AR interfaces over no AR interface. Furthermore, the Pedestrian lights HUD was more effective than no AR interface in a statistically significant manner, as it led to participants more frequently keeping the button pressed. The Fixed pedestrian lights scored lower than the other interfaces, presumably due to low saliency and the fact that participants had to visually identify both this AR interface and the AV.
Discussion: In conclusion, while users favour AR in AV-pedestrian interactions over no AR, its effectiveness depends on design factors like location, visibility, and visual attention demands. In conclusion, this work provides important insights into the use of AR outdoors. The findings illustrate that, in these circumstances, a clear and easily interpretable AR interface is of key importance.","augmented reality; pedestrian safety; anchoring; see-through AR; head-mounted device (HMD)","en","journal article","","","","","","","","","","","Human-Robot Interaction","","",""
"uuid:9a608f16-a40d-4f81-91b8-9b254d80dbf1","http://resolver.tudelft.nl/uuid:9a608f16-a40d-4f81-91b8-9b254d80dbf1","WhereWeMove: The housing game that supports governments and residents in joining efforts for climate action","Cortes Arevalo, V.J. (TU Delft Policy Analysis); Bekebrede, G. (TU Delft Organisation & Governance); Verbraeck, A. (TU Delft Policy Analysis); Filatova, T. (TU Delft Policy Analysis); Mutlu, A. (TU Delft Policy Analysis); Abebe, Y.A. (TU Delft Hydraulic Structures and Flood Risk); Taylor, Zac (TU Delft Urban Development Management)","","2024","","","en","report","Delft University of Technology","","","","","","","","","","Policy Analysis","","",""
"uuid:66a1ffe2-9f54-4c7e-b1ab-f203edbd060e","http://resolver.tudelft.nl/uuid:66a1ffe2-9f54-4c7e-b1ab-f203edbd060e","Evaluation of blinds control techniques for daylight and visual comfort in complex real-world conditions","Brembilla, E. (TU Delft Environmental & Climate Design); Wang, Taoning (Lawrence Berkeley National Laboratory); Theodoropoulou, Panagiota (Student TU Delft); Beck, Wouter (Hunter Douglas NL)","","2024","The presence of sensor networks to monitor environmental conditions and the automation of blinds and lighting systems controls is now commonplace in buildings, especially public ones with a high number of occupants. However, implementing control algorithms that are sufficiently reactive to variable sky conditions and that actually meet occupants’ needs is still a challenge. In the present study, we investigate and compare advanced and simple control algorithms developed for a variable occupancy, open space, small sized conference venue. Operation and performance resulting from an optimized approach are assumed to be the benchmark strategy, and two other control algorithms of varying complexity are compared with it. Results show that the optimized control strategy performs best overall, but only marginally compared to the other two strategies. It performed especially well in meeting glare protection requirements, as a glare-related parameter was embedded into its objective function, but it also led to erratic movements of the blind slats’ tilt and it required significantly higher computation times than rule-based control strategies. These two factors make it impossible to implement such strategy as it is in the real building, and indicate that a practical control implementation can be more effective than an optimal one.","daylight; blinds automated control; complex fenestration systems; radiance matrix methods","en","conference paper","IBPSA","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-13","","","Environmental & Climate Design","","",""
"uuid:4afeb65f-c39c-464a-8a5b-dbd75f809a10","http://resolver.tudelft.nl/uuid:4afeb65f-c39c-464a-8a5b-dbd75f809a10","Effects of surface roughness on the propulsive performance of pitching foils","Vilumbrales-Garcia, Rodrigo (University of Southampton); Kurt, Melike (University of Southampton); Weymouth, Gabriel D. (TU Delft Ship Hydromechanics; University of Southampton); Ganapathisubramani, Bharathram (University of Southampton)","","2024","The hydrodynamic influence of surface texture on static surfaces ranges from large drag penalties (roughness) to potential performance benefits (shark-like skin). Although it is of wide-ranging research interest, the impact of roughness on flapping systems has received limited attention. In this work, we explore the effect of roughness on the unsteady performance of a harmonically pitching foil through experiments using foils with different surface roughness, at a fixed Strouhal number and within the Reynolds number range of. The foils' surface roughness is altered by changing the distribution of spherical-cap-shaped elements over the propulsor area. We find that the addition of surface roughness does not improve the performance compared with a smooth surface over the range considered. The analysis of the flow fields shows near-identical wakes regardless of the foil's surface roughness. The performance reduction mainly occurs due to an increase in profile drag. However, we find that the drag penalty due to roughness is reduced from for a static foil to for a flapping foil at the same mean angle of attack, with the strongest decrease measured at the highest. Our findings highlight that the effect of roughness on dynamic systems is very different than that on static systems; thereby, it cannot be estimated by only using information obtained from static cases. This also indicates that the performance of unsteady, flapping systems is more robust to the changes in surface roughness.","flow–structure interactions; swimming/flying; drag reduction","en","journal article","","","","","","","","","","","Ship Hydromechanics","","",""
"uuid:94f8fbdc-cdf8-44a1-8bf8-3a441a5ad631","http://resolver.tudelft.nl/uuid:94f8fbdc-cdf8-44a1-8bf8-3a441a5ad631","Salinity-induced succession of phototrophic communities in a southwestern Siberian soda lake during the solar activity cycle","Samylina, Olga S. (Russian Academy of Sciences); Kosyakova, Anastasia I. (Russian Academy of Sciences; Moscow State University); Krylov, Artem A. (Russian Academy of Sciences); Sorokin, Dimitry Y. (TU Delft BT/Environmental Biotechnology; Russian Academy of Sciences); Pimenov, Nikolay V. (Russian Academy of Sciences)","","2024","A variety of lakes located in the dry steppe area of southwestern Siberia are exposed to rapid climatic changes, including intra-century cycles with alternating dry and wet phases driven by solar activity. As a result, the salt lakes of that region experience significant fluctuations in water level and salinity, which have an essential impact on the indigenous microbial communities. But there are few microbiological studies that have analyzed this impact, despite its importance for understanding the functioning of regional water ecosystems. This work is a retrospective study aimed at analyzing how solar activity-related changes in hydrological regime affect phototrophic microbial communities using the example of the shallow soda lake Tanatar VI, located in the Kulunda steppe (Altai Region, Russia, southwestern Siberia). The main approach used in this study was the comparison of hydrochemical and microscopic data obtained during annual field work with satellite and solar activity data for the 12-year observation period (2011–2022). The occurrence of 33 morphotypes of cyanobacteria, two key morphotypes of chlorophytes, and four morphotypes of anoxygenic phototrophic bacteria was analyzed due to their easily recognizable morphology. During the study period, the lake surface changed threefold and the salinity changed by more than an order of magnitude, which strongly correlated with the phases of the solar activity cycles. The periods of high (2011–2014; 100–250 g/L), medium (2015–2016; 60 g/L), extremely low (2017–2020; 13–16 g/L), and low (2021–2022; 23–34 g/L) salinity with unique biodiversity of phototrophic communities were distinguished. This study shows that solar activity cycles determine the dynamics of the total salinity of a southwestern Siberian soda lake, which in turn determines the communities and microorganisms that will occur in the lake, ultimately leading to cyclical changes in alternative states of the ecosystem (dynamic stability).","Diversity; Dynamic stability; Phototrophs; Salinity; Soda lakes; Solar activity","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:3f609a0a-b277-4595-9061-88160f8a80ef","http://resolver.tudelft.nl/uuid:3f609a0a-b277-4595-9061-88160f8a80ef","Optomechanical methodology for characterizing the thermal properties of 2D materials","Liu, Hanqing (TU Delft Dynamics of Micro and Nano Systems); Brahmi, Hatem (ASML); Boix-Constant, Carla (Universidad de Valencia (ICMol)); van der Zant, H.S.J. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Steeneken, P.G. (TU Delft Dynamics of Micro and Nano Systems; Kavli institute of nanoscience Delft); Verbiest, G.J. (TU Delft Dynamics of Micro and Nano Systems)","","2024","Heat transport in two dimensions is fundamentally different from that in three dimensions. As a consequence, the thermal properties of 2D materials are of great interest, from both scientific and application points of view. However, few techniques are available for the accurate determination of these properties in ultrathin suspended membranes. Here, we present an optomechanical methodology for extracting the thermal expansion coefficient, specific heat, and thermal conductivity of ultrathin membranes made of 2H-TaS2, FePS3, polycrystalline silicon, MoS2, and WSe2. The obtained thermal properties are in good agreement with the values reported in the literature for the same materials. Our work provides an optomechanical method for determining the thermal properties of ultrathin suspended membranes, which are difficult to measure otherwise. It provides a route toward improving our understanding of heat transport in the 2D limit and facilitates engineering of 2D structures with a dedicated thermal performance.","","en","journal article","","","","","","","","","","","Dynamics of Micro and Nano Systems","","",""
"uuid:ee4cdfe3-53c1-4962-b2c0-cac021779085","http://resolver.tudelft.nl/uuid:ee4cdfe3-53c1-4962-b2c0-cac021779085","The value of collision feedback in robotic surgical skills training","Postema, R.R. (TU Delft Biomechanical Engineering; Amsterdam UMC); Hardon, Hidde (Amsterdam UMC; Vrije Universiteit Amsterdam); Rahimi, A. Masie (Amsterdam UMC; Amsterdam Skills Centre for Health Sciences); Horeman, Roel; Nickel, Felix (University of Heidelberg); Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology); Bloemendaal, A.L.A. (TU Delft Medical Instruments & Bio-Inspired Technology; Reinier de Graaf Gasthuis); van der Elst, M. (TU Delft Medical Instruments & Bio-Inspired Technology; Reinier de Graaf Gasthuis); van der Peet, Donald L. (Amsterdam UMC); Daams, Freek (Amsterdam UMC); Hardon, S.F. (TU Delft Medical Instruments & Bio-Inspired Technology; Amsterdam UMC); Horeman, T. (TU Delft Medical Instruments & Bio-Inspired Technology)","","2024","Collision feedback about instrument and environment interaction is often lacking in robotic surgery training devices. The PoLaRS virtual reality simulator is a newly developed desk trainer that overcomes drawbacks of existing robot trainers for advanced laparoscopy. This study aimed to assess the effect of haptic and visual feedback during training on the performance of a robotic surgical task. Robotic surgery-naïve participants were randomized and equally divided into two training groups: Haptic and Visual Feedback (HVF) and No Haptic and Visual Feedback. Participants performed two basic virtual reality training tasks on the PoLaRS system as a pre- and post-test. The measurement parameters Time, Tip-to-tip distance, Path length Left/Right and Collisions Left/Right were used to analyze the learning curves and statistically compare the pre- and post-tests performances. In total, 198 trials performed by 22 participants were included. The visual and haptic feedback did not negatively influence the time to complete the tasks. Although no improvement in skill was observed between pre- and post-tests, the mean rank of the number of collisions of the right grasper (dominant hand) was significantly lower in the HVF feedback group during the second post-test (Mean Rank = 8.73 versus Mean Rank = 14.27, U = 30.00, p = 0.045). Haptic and visual feedback during the training on the PoLaRS system resulted in fewer instrument collisions. These results warrant the introduction of haptic feedback in subjects with no experience in robotic surgery. The PoLaRS system can be utilized to remotely optimize instrument handling before commencing robotic surgery in the operating room.","Haptic feedback; Patient safety; Robotic surgery; Simulation training; Skills acquisition; Visual feedback","en","journal article","","","","","","","","","","Biomechanical Engineering","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:ee94c940-6ee0-49bf-8ed4-14c76081484b","http://resolver.tudelft.nl/uuid:ee94c940-6ee0-49bf-8ed4-14c76081484b","An experimental study on the aerodynamic loads of a floating offshore wind turbine under imposed motions","Taruffi, F. (TU Delft Wind Energy); Miranda Novais, F. (Politecnico di Milano; Maritime Research Institute Netherlands (MARIN)); Viré, A.C. (TU Delft Wind Energy)","","2024","The rotor of a floating wind turbine is subject to complex aerodynamics due to changes in relative wind speeds at the blades and potential local interactions between blade sections and the rotor near wake. These complex interactions are not yet fully understood. Lab-scale experiments are highly relevant for capturing these phenomena and provide means for the validation of numerical design tools. This paper presents a new wind tunnel experimental setup able to study the aerodynamic response of a wind turbine rotor when subjected to prescribed motions. The present study uses a 1:148 scale model of the DTU 10 MW reference wind turbine mounted on top of a 6 degrees of freedom parallel kinematic robotic platform. Firstly, the thrust variation of the turbine is investigated when single degree of freedom harmonic motions are imposed by the platform, with surge, pitch and yaw being considered in this study. For reduced frequencies greater than 1.2, it is found that the thrust variation is amplified by up to 150 % compared to the quasi-steady value when the turbine is subject to pitch and surge motions, regardless of the amplitude of motion. A similar behaviour is also noticed under yaw motions. Secondly, realistic 6 degrees of freedom motions are imposed by the platform. The motions are derived from FAST simulations performed on the full-scale turbine coupled with the TripleSpar floater, and the tests aim at exploring the thrust force dynamics for different sea states and wind conditions, obtaining reasonable agreement with the simulations. Finally, the work shows the capabilities of an off-the-shelf hexapod to conduct hybrid testing of floating offshore wind turbines in wind tunnels, as well as its limitations in performing such tests.","","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:15ddc123-7a5c-4083-9dab-662f639a8bb4","http://resolver.tudelft.nl/uuid:15ddc123-7a5c-4083-9dab-662f639a8bb4","Global well-posedness and interior regularity of 2D Navier–Stokes equations with stochastic boundary conditions","Agresti, A. (TU Delft Analysis; Institute of Science and Technology Austria); Luongo, Eliseo (Istituto Nanoscienze-CNR and Scuola Normale Superiore)","","2024","The paper is devoted to the analysis of the global well-posedness and the interior regularity of the 2D Navier–Stokes equations with inhomogeneous stochastic boundary conditions. The noise, white in time and coloured in space, can be interpreted as the physical law describing the driving mechanism on the atmosphere–ocean interface, i.e. as a balance of the shear stress of the ocean and the horizontal wind force.","60H15; 76D03 (47A60, 35J25)","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:414b851a-b91a-4b32-a23c-600cecf8279c","http://resolver.tudelft.nl/uuid:414b851a-b91a-4b32-a23c-600cecf8279c","Shape-Changing Wood Joints in Crafts and Industry and Their Potential for Building Construction and Wood Culture: State-of-the-Art of Utilizing the Hygrocopicity and Resulting Dimensional Change of Wood for the Moisture-Induced Joining of Wooden Elements","Salzberger, M.F. (TU Delft Architectural Technology)","","2024","Timber has regained popularity in construction in recent years due to its ecological benefits. The connection methods used in this study play a vital role in the sustainability of structures and materials. Monomaterial timber connections are sustainable alternatives to metal fasteners and adhesives commonly used in construction. Wood is an anisotropic material with dimensional changes resulting from changes in atmospheric conditions. Understanding and accounting for this property are crucial for the longevity and functionality of wooden structures. The cumulative knowledge of wood´s material characteristics and its use in design, construction, and human culture can be defined as wood culture developed through artists’ and craftsmen’s experiences, science, and industry. The development of various techniques by artisans to leverage the dimensional change in wood to join timber elements is a major contribution to wood culture. In contrast, until now, the timber industry has mainly focused on limiting or controlling these changes in standardized production and has neglected their use for joining timber elements. However, technological advances have changed dramatically. The digital manufacturing and analysis of wood structures have the potential to guide machine tools and may allow the integration of dimensional changes, especially in the design and construction of timber joints. This study explores the state-of-the-art utilization of dimensional changes in timber to join elements in craft, material science, and industrial production. The potential of techniques utilizing this behavior for innovation in modern design and construction and their implications for wood culture were examined. Research gaps and avenues for further research are identified.","densified wood; dimensional change; timber construction; timber technology; wood connectors; wood; wood joints","en","journal article","","","","","","","","","","","Architectural Technology","","",""
"uuid:d7a3f29d-a0db-4c89-acd1-29a95daa235f","http://resolver.tudelft.nl/uuid:d7a3f29d-a0db-4c89-acd1-29a95daa235f","Morphological and microstructural characterization of an ancient Chola bronze statuette by neutron‑based non‑invasive techniques","Cantini, Francesco (Università degli Studi di Firenze (UNIFI), Dipartimento di Fisica, Sesto Fiorentino, Italy; Consiglio Nazionale delle Ricerche, Istituto di Fisica Applicata Nello Carrara (CNR-IFAC), Sesto Fiorentino, Italy; Istituto Nazionale di Fisica Nucleare, Laboratorio di Tecniche Nucleari per i Beni Culturali (INFN-Labec), Sesto Fiorentino, Italy); Creange, Sara (Rijksmuseum); Li, Y. (TU Delft RST/Neutron and Positron Methods in Materials); van Eijck, L. (TU Delft RST/Neutron and Positron Methods in Materials); Kardjilov, Nikolay (Helmholtz-Zentrum Berlin (HZB), Wannsee, Germany); Kabra, Saurabh (ISIS Neutron and Muon Facility, STFC-UKRI, Rutherford-Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, UK); Grazzi, Francesco (Consiglio Nazionale delle Ricerche, Istituto di Fisica Applicata Nello Carrara (CNR-IFAC), Sesto Fiorentino, Italy; Istituto Nazionale di Fisica Nucleare, Laboratorio di Tecniche Nucleari per i Beni Culturali (INFN-Labec), Sesto Fiorentino, Italy)","","2024","The evolution of metallurgy is a fundamental aspect related to the knowledge of the technological level of ancient civilizations, for which the information was mostly part of an oral tradition. The ancient, preserved artefacts are the only keepers of this long gone knowledge. Most advanced non-invasive techniques provide us the key to access it. Neutron techniques are nowadays the only available approach for revealing, non-destructively and with good spatial resolution, the morphological and microstructural properties within the whole volume of densely composed artefacts such as bronze statues. Application of neutron methods allows us to learn about ancient artefact manufacturing methods and to study at a very detailed level the current conservation status in their different parts. As part of a research project dedicated to the study of ancient Asian bronzes led by the Rijksmuseum Metal Conservation Department, four statues from the Rijksmuseum Asian collection were analysed using non-invasive neutron techniques. In this work, we present the investigation of a South Indian bronze statuette depicting Shiva in the form of Chandrasekhara (AK-MAK-1291, c. 1000–1200 A.D.) by means of white beam tomography, energy-selective neutron imaging (performed on CONRAD-2 at HZB, DE, and on FISH at TU-Delft, NL), and neutron diffraction (on ENGIN-X at ISIS, UK). The application of neutron imaging revealed the inner structure of the statue and allowed us to investigate the conservation state and potential cracking on the surface and in the bulk, to understand the interconnection of the different sections of the statue, and to obtain clues about the manufacturing processes. These morphological and microstructural results were employed to guide neutron diffraction analyses that allowed us to precisely characterize compositional differences, the presence of dendrites and columnar growth peak structures related to casting. This work is a complete non-invasive analytical investigation on an archaeological bronze artefact, providing outstanding results: from a quantitative analysis of the composition and microstructure to an in-depth morphological analysis capable of unveiling details on the ancient casting methods of the statue.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-28","","","RST/Neutron and Positron Methods in Materials","","",""
"uuid:e8bdc6ca-956d-4372-a91f-ae3a7977564a","http://resolver.tudelft.nl/uuid:e8bdc6ca-956d-4372-a91f-ae3a7977564a","Integrated careful homes for differentiated needs","Eijkelenboom, A.M. (TU Delft Environmental & Climate Design; EGM Architects); Alkema, Rosanne (EGM Architects); Meinsma, Heleen (EGM Architects); Hammer, Willemineke (EGM Architects)","","2024","Due to the ageing society, policy focuses on independent living of elderly in need for care. While the preferences of the elderly to live autonomously vary, there is limited information on variation in needs for the physical environment, e.g., shared and private places. A pilot study was done to develop insights into preferences for social and physical environment of the elderly in need for care. A questionnaire (N=52) and workshop (N=22) were conducted with future elderly. The study showed that preferences for ways of living largely varied. Many were willing to share facilities and help each other, although they did not want to provide somatic care. Based on the results two new concepts were explored, i.e. farm like housing in the city centre and small-scale housing with friends. The concepts, resulting from the questionnaire and workshop, suggest that the method can be used to further explore connections between preferences and design.","assisted living; independent living; communal living; preferences; session 4b","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:2bdd5d0a-032a-4b54-906e-32f82f19ab6a","http://resolver.tudelft.nl/uuid:2bdd5d0a-032a-4b54-906e-32f82f19ab6a","The Mechanism behind Vibration Assisted Fluidization of Cohesive Micro-Silica","Kamphorst, R. (TU Delft ChemE/Product and Process Engineering); van der Sande, P.C. (TU Delft ChemE/Product and Process Engineering); Wu, K. (TU Delft ChemE/Product and Process Engineering); Wagner, E.C. (TU Delft ChemE/O&O groep); David, M.K. (TU Delft ChemE/O&O groep); Meesters, G.M.H. (TU Delft ChemE/Product and Process Engineering); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering)","","2024","Vibro-assisted fluidization of cohesive micro-silica has been studied by means of X-ray imaging, pressure drop measurements, and off-line determination of the agglomerate size. Pressure drop and bed height development could be explained by observable phenomena taking place in the bed; slugging, channeling, fluidization or densification. It was observed that channeling is the main cause of poor fluidization of the micro-silica, resulting in poor gas-solid contact and little internal mixing. Improvement in fluidization upon starting the mechanical vibration was achieved by disrupting the channels. Agglomerate sizes were found to not significantly change during experiments.","agglomeration; assistance methods; cohesive powder; fluidized bed; X-ray imaging","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:bdda77a8-1cfc-4a48-aa11-f2cbe5062a57","http://resolver.tudelft.nl/uuid:bdda77a8-1cfc-4a48-aa11-f2cbe5062a57","Preferences and satisfaction with social comfort of outpatient workers in six hospitals before and during the COVID-19 pandemic","Eijkelenboom, A.M. (TU Delft Environmental & Climate Design; EGM Architects)","","2024","A PhD study was carried out on comfort and health of workers in outpatient areas because hospital workers are generally less satisfied with comfort than patients and outpatient areas were understudied. To better understand differences in preferences and satisfaction of individuals, profiles were produced with Two-Step Cluster analysis, based on a questionnaire, responded by 556 outpatient workers, and building inspection of six hospital locations. Thereafter, interviews were performed to explain the preferences. As the COVID-19 pandemic started after production of the profiles, changes due to de pandemic were included. A gap between preferences and satisfaction was identified for all profiles. Also, those with similar preferences for social comfort (privacy, interaction, distraction) performed similar activities. Contact with others was for all profiles important, while satisfaction was overall high before the COVID-19 pandemic. Due to the shift to digital care during the COVID-19 pandemic, impoverished interaction was a main concern of the outpatient workers. In conclusion the profiles for social comfort show that preferences for social comfort are associated with work-related aspects and can change. The profiles may open a new horizon to accommodate for flexibility and variety beyond standardized solutions.","social comfort; hospital staff; COVID-19 pandemic; preferences; section 1c","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:3443ff21-ce7b-4e35-b9a0-a6cee3c297e5","http://resolver.tudelft.nl/uuid:3443ff21-ce7b-4e35-b9a0-a6cee3c297e5","Integration of EBD principles in a futureproof academic hospital from campus to bed","Eijkelenboom, A.M. (TU Delft Environmental & Climate Design; EGM Architects); Hobo, Iris (Radboud University Medical Center); Bleeker, René (Radboud University Medical Center); van den Berg, Daniël (EGM Architects)","","2024","Design solutions bases on Evidence Based Design (EBD) principles vary due to the context and organizational aspects of hospitals. This paper explains how EBD principles were included during the design process of an academic hospital, including design guidelines that were developed with a representative group of key stakeholders from the organization. The hospital comprises several buildings on a campus, that also includes several university buildings. Some of the hospital buildings are connected through “the main axe.” The principles were applied on different scales in the design of a new main building and transformation of an existing building and the main axe, connecting other buildings. Specific design solutions for daylight access, connection to nature, art, privacy, and interaction are discussed.","evidence based design; hospital; architecture; session 1a","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:a29c1fb2-05f7-4560-a053-9e02163a7560","http://resolver.tudelft.nl/uuid:a29c1fb2-05f7-4560-a053-9e02163a7560","Release of phosphorus through pretreatment of waste activated sludge differs essentially from that of carbon and nitrogen resources: Comparative analysis across four wastewater treatment facilities","Deng, Shaoyu (Beijing Forestry University); Liu, J. (Beijing Forestry University); Yang, Xiaofan (Beijing Forestry University); Sun, Dezhi (Beijing Forestry University); Wang, Aijie (Harbin Institute of Technology); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Cheng, Xiang (Beijing Forestry University)","","2024","The accumulation of phosphorus in activated sludge in wastewater treatment plants (WWTPs) provides potential for phosphorus recovery from sewage. This study delves into the potential for releasing phosphorus from waste activated sludge through two distinct treatment methods—thermal hydrolysis and pH adjustment. The investigation was conducted with activated sludge sourced from four WWTPs, each employing distinct phosphorus removal strategies. The findings underscore the notably superior efficacy of pH adjustment in solubilizing sludge phosphorus compared to the prevailing practice of thermal hydrolysis, widely adopted to enhance sludge digestion. The reversibility of phosphorus release within pH fluctuations spanning 2 to 12 implies that the release of sludge phosphorus can be attributed to the dissolution of phosphate precipitates. Alkaline sludge treatment induced the concurrent liberation of COD, nitrogen, and phosphorus through alkaline hydrolysis of sludge biomass and the dissolution of iron or aluminium phosphates, offering potential gains in resource recovery and energy efficiency.","Activated sludge; Alkaline treatment; Resource recovery; Thermal hydrolysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-09","","","BT/Environmental Biotechnology","","",""
"uuid:36d17527-0a3a-4322-966d-21d47ed989c2","http://resolver.tudelft.nl/uuid:36d17527-0a3a-4322-966d-21d47ed989c2","Simulation-based mathematical learning for higher education students from heterogeneous backgrounds","Campos, Neila (Universitat Oberta de Catalunya; University of Cantabria); Corlu, Canan G. (Boston University); Nogal Macho, M. (TU Delft Integral Design & Management); Juan, Angel A. (Universitat Oberta de Catalunya; Universitat Politécnica de Valencia); Caliz, Cristina (Euncet Business School)","","2024","This paper explores the use of simulation-based training for mathematical learning in undergraduate and graduate mathematics, science, and engineering courses. Simulation-based training offers the advantages of active learning and inquiry-based learning techniques. Furthermore, it provides extensive flexibility, ranging from user-level usage of simulations to the modification or creation of new possibilities by the student, thus engaging different cognitive levels to achieve the learning objectives. This is particularly interesting in groups consisting of students from diverse backgrounds and levels, due to factors such as their international origin or varying prior education, especially in interdisciplinary Master’s degree programmes. Additionally, in online or blended environments (which have become widespread during the last years), simulation-based learning has the advantage of granting students a certain degree of autonomy, which can, to some extent, compensate for the absence of the instructor’s physical presence.","cognitive levels; Higher education; mathematical e-learning; online education; simulation-based education","en","journal article","","","","","","","","2024-08-13","","","Integral Design & Management","","",""
"uuid:f649af0c-c451-4781-895b-e67c34016fbd","http://resolver.tudelft.nl/uuid:f649af0c-c451-4781-895b-e67c34016fbd","Adapting Temperature Predictions to MR Imaging in Treatment Position to Improve Simulation-Guided Hyperthermia for Cervical Cancer","Vilasboas-Ribeiro, Iva (Erasmus MC); Sumser, Kemal (Eindhoven University of Technology); Nouwens, Sven (Eindhoven University of Technology); Feddersen, Theresa (Erasmus MC); Heemels, W. P.M.H. (Eindhoven University of Technology); van Rhoon, G.C. (TU Delft RST/Applied Radiation & Isotopes; Erasmus MC); Paulides, Margarethus M. (Eindhoven University of Technology)","","2024","Hyperthermia treatment consists of elevating the temperature of the tumor to increase the effectiveness of radiotherapy and chemotherapy. Hyperthermia treatment planning (HTP) is an important tool to optimize treatment quality using pre-treatment temperature predictions. The accuracy of these predictions depends on modeling uncertainties such as tissue properties and positioning. In this study, we evaluated if HTP accuracy improves when the patient is imaged inside the applicator at the start of treatment. Because perfusion is a major uncertainty source, the importance of accurate treatment position and anatomy was evaluated using different perfusion values. Volunteers were scanned using MR imaging without ('planning setup') and with the MR-compatible hyperthermia device ('treatment setup'). Temperature-based quality indicators were used to assess the differences between the standard, apparent and the optimized hyperthermia dose. We conclude that pre-treatment imaging can improve HTP predictions accuracy but also, that tissue perfusion modelling is crucial if temperature-based optimization is applied.","Hyperthermia treatment planning (HTP); MR imaging; optimization approach; perfusion; thermal modeling","en","journal article","","","","","","","","","","","RST/Applied Radiation & Isotopes","","",""
"uuid:8babbc9c-1424-42fb-9231-0046e0acc023","http://resolver.tudelft.nl/uuid:8babbc9c-1424-42fb-9231-0046e0acc023","Improving End-to-End Models for Children’s Speech Recognition","Patel, T.B. (TU Delft Multimedia Computing); Scharenborg, O.E. (TU Delft Multimedia Computing)","","2024","Children’s Speech Recognition (CSR) is a challenging task due to the high variability in children’s speech patterns and limited amount of available annotated children’s speech data. We aim to improve CSR in the often-occurring scenario that no children’s speech data is available for training the Automatic Speech Recognition (ASR) systems. Traditionally, Vocal Tract Length Normalization (VTLN) has been widely used in hybrid ASR systems to address acoustic mismatch and variability in children’s speech when training models on adults’ speech. Meanwhile, End-to-End (E2E) systems often use data augmentation methods to create child-like speech from adults’ speech. For adult speech-trained ASRs, we investigate the effectiveness of augmentation methods; speed perturbations and spectral augmentation, along with VTLN, in an E2E framework for the CSR task, comparing these across Dutch, German, and Mandarin. We applied VTLN at different stages (training/test) of the ASR and conducted age and gender analyses. Our experiments showed highly similar patterns across the languages: Speed Perturbations and Spectral Augmentation yield significant performance improvements, while VTLN provided further improvements while maintaining recognition performance on adults’ speech (depending on when it is applied). Additionally, VTLN showed performance improvement for both male and female speakers and was particularly effective for younger children.","children’s speech recognition; speed perturbations; spectral augmentation; vocal tract length normalization; end-to-end automatic speech recognition","en","journal article","","","","","","","","","","","Multimedia Computing","","",""
"uuid:e30d2a88-46f8-4a24-a2b8-36fd684345fe","http://resolver.tudelft.nl/uuid:e30d2a88-46f8-4a24-a2b8-36fd684345fe","Microstrain effects of laser-ablated Au nanoparticles in enhancing CZTS-based 1 Sun photodetector devices","Gezgin, Serap Yiğit (Selçuk University); Belaid, Walid (Selçuk University); Basyooni, Mohamed A. (TU Delft Dynamics of Micro and Nano Systems; Selçuk University; Necmettin Erbakan University); Ramazan Ekerde, Yasin (Necmettin Erbakan University); Kılıç, Hamdi Şükür (Selçuk University)","","2024","Copper zinc tin sulfide (CZTS) thin films were synthesized on soda lime glass using pulsed laser deposition (PLD) at room temperature. Introducing gold nanoparticles (AuNPs) in a sandwich structure led to increased CZTS particle size and a shift in the localized surface plasmon resonance (LSPR) peak of the AuNPs, influenced by different laser energy levels. The absorption measurements revealed intriguing behavior across the visible and near-infrared (NIR) regions, making these films appealing for 1 Sun photodetectors. Furthermore, the presence of AuNPs in the sandwich structure reduced microstrain effects, measuring 1.94 × 10−3 compared to 3.38 × 10−3 in their absence. This reduction directly enhances carrier transport, which is particularly beneficial for accelerating the performance of photodetector devices. This effect of AuNPs also contributed to higher dielectric coefficients, further improving the photodetector performance. Under 1 Sun illumination conditions, this enhancement resulted in a rapid rising time of 95.4 ms, showcasing the potential for faster photodetection.","","en","journal article","","","","","","","","","","","Dynamics of Micro and Nano Systems","","",""
"uuid:e9206ded-75e9-44bd-a3b6-e30f1738ad4d","http://resolver.tudelft.nl/uuid:e9206ded-75e9-44bd-a3b6-e30f1738ad4d","Quantifying the minimum localization uncertainty of image scanning localization microscopy","Kalisvaart, D. (TU Delft Team Carlas Smith); Hung, S. (TU Delft Team Carlas Smith); Smith, C.S. (TU Delft BN/Nynke Dekker Lab; TU Delft ImPhys/Rieger group; TU Delft Team Carlas Smith; TU Delft ImPhys/Computational Imaging)","","2024","Modulation enhanced single-molecule localization microscopy (meSMLM), where emitters are sparsely activated with sequentially applied patterned illumination, increases the localization precision over single-molecule localization microscopy (SMLM). The precision improvement of modulation enhanced SMLM is derived from retrieving the position of an emitter relative to individual illumination patterns, which adds to existing point spread function information from SMLM. Here, we introduce SpinFlux: modulation enhanced localization for spinning disk confocal microscopy. SpinFlux uses a spinning disk with pinholes in its illumination and emission paths, to sequentially illuminate regions in the sample during each measurement. The resulting intensity-modulated emission signal is analyzed for each individual pattern to localize emitters with improved precision. We derive a statistical image formation model for SpinFlux and we quantify the theoretical minimum localization uncertainty in terms of the Cramér-Rao lower bound. Using the theoretical minimum uncertainty, we compare SpinFlux to localization on Fourier reweighted image scanning microscopy reconstructions. We find that localization on image scanning microscopy reconstructions with Fourier reweighting ideally results in a global precision improvement of 2.1 over SMLM. When SpinFlux is used for sequential illumination with three patterns around the emitter position, the localization precision improvement over SMLM is twofold when patterns are focused around the emitter position. If four donut-shaped illumination patterns are used for SpinFlux, the maximum local precision improvement over SMLM is increased to 3.5. Localization of image scanning microscopy reconstructions thus has the largest potential for global improvements of the localization precision, where SpinFlux is the method of choice for local refinements.","","en","journal article","","","","","","","","","","","Team Carlas Smith","","",""
"uuid:26ea1f84-4490-47cf-b174-d89238393cf5","http://resolver.tudelft.nl/uuid:26ea1f84-4490-47cf-b174-d89238393cf5","Augmenting Media Experiences with Affective Haptics","Ooms, Simone (Universiteit Utrecht); Röggla, Thomas (Centrum Wiskunde & Informatica (CWI)); Cesar, Pablo (TU Delft Multimedia Computing); El Ali, Abdallah (Centrum Wiskunde and Informatica)","","2024","Within our Distributed and Interactive Systems research group, we focus on affective haptics, where we design and develop systems that can enhance human emotional states through the sense of touch. Such artificial haptic sensations can potentially augment and enhance our mind, body, and (virtual) social connections. In three works—voice communication, news consumption, and virtual embodiment—we explore the effects of enriching media experiences with thermal and vibrotactile affective haptics, and how such stimulation influences our affective perception.","human-centered computing; human computer interaction (HCI); social and professional topics; professional topics; computing and business; socio-technical systems","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-02","","","Multimedia Computing","","",""
"uuid:0eca0fc2-807b-45e8-8fb6-046e9163a8c1","http://resolver.tudelft.nl/uuid:0eca0fc2-807b-45e8-8fb6-046e9163a8c1","Demystifying polyphosphate-accumulating organisms relevant to wastewater treatment: A review of their phylogeny, metabolism, and detection","Ruiz Hadad, L. (King Abdullah University of Science and Technology); Ali, Muhammad (Trinity College Dublin); Pronk, M. (TU Delft BT/Environmental Biotechnology); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Saikaly, Pascal E. (King Abdullah University of Science and Technology)","","2024","Currently, the most cost-effective and efficient method for phosphorus (P) removal from wastewater is enhanced biological P removal (EPBR) via polyphosphate-accumulating organisms (PAOs). This study integrates a literature review with genomic analysis to uncover the phylogenetic and metabolic diversity of the relevant PAOs for wastewater treatment. The findings highlight significant differences in the metabolic capabilities of PAOs relevant to wastewater treatment. Notably, Candidatus Dechloromonas and Candidatus Accumulibacter can synthesize polyhydroxyalkanoates, possess specific enzymes for ATP production from polyphosphate, and have electrochemical transporters for acetate and C4-dicarboxylates. In contrast, Tetrasphaera, Candidatus Phosphoribacter, Knoellia, and Phycicoccus possess PolyP-glucokinase and electrochemical transporters for sugars/amino acids. Additionally, this review explores various detection methods for polyphosphate and PAOs in activated sludge wastewater treatment plants. Notably, FISH-Raman spectroscopy emerges as one of the most advanced detection techniques. Overall, this review provides critical insights into PAO research, underscoring the need for enhanced strategies in biological phosphorus removal.","Ca. accumulibacter; Ca. phosphoribacter; Enhanced biological phosphorus removal (EBPR); Knoellia; Phycicoccus; Polyphosphate-accumulating organisms (PAOs); Tetrasphaera","en","review","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:a7582c0e-bbf1-4450-af87-522f72b40123","http://resolver.tudelft.nl/uuid:a7582c0e-bbf1-4450-af87-522f72b40123","Digital twin in high throughput chromatographic process development for monoclonal antibodies","Picanço Castanheira Da Silva, T. (TU Delft BT/Bioprocess Engineering); Eppink, M.H.M. (Wageningen University & Research); Ottens, M. (TU Delft BT/Design and Engineering Education)","","2024","The monoclonal antibody (mAb) industry is becoming increasingly digitalized. Digital twins are becoming increasingly important to test or validate processes before manufacturing. High-Throughput Process Development (HTPD) has been progressively used as a tool for process development and innovation. The combination of High-Throughput Screening with fast computational methods allows to study processes in-silico in a fast and efficient manner. This paper presents a hybrid approach for HTPD where equal importance is given to experimental, computational and decision-making stages. Equilibrium adsorption isotherms of 13 protein A and 16 Cation-Exchange resins were determined with pure mAb. The influence of other components in the clarified cell culture supernatant (harvest) has been under-investigated. This work contributes with a methodology for the study of equilibrium adsorption of mAb in harvest to different protein A resins and compares the adsorption behavior with the pure sample experiments. Column chromatography was modelled using a Lumped Kinetic Model, with an overall mass transfer coefficient parameter (kov). The screening results showed that the harvest solution had virtually no influence on the adsorption behavior of mAb to the different protein A resins tested. kov was found to have a linear correlation with the sample feed concentration, which is in line with mass transfer theory. The hybrid approach for HTPD presented highlights the roles of the computational, experimental, and decision-making stages in process development, and how it can be implemented to develop a chromatographic process. The proposed white-box digital twin helps to accelerate chromatographic process development.","Harvest High-throughput screening; High-throughput process development; Lumped kinetic model; Overall mass transfer coefficient","en","journal article","","","","","","","","","","","BT/Bioprocess Engineering","","",""
"uuid:0caa221f-fad2-4a1f-af88-d615b9394054","http://resolver.tudelft.nl/uuid:0caa221f-fad2-4a1f-af88-d615b9394054","Particle dynamics in horizontal stirred bed reactors characterized by single-photon emission radioactive particle tracking","van der Sande, P.C. (TU Delft ChemE/Product and Process Engineering); Wagner, E.C. (TU Delft ChemE/O&O groep); de Mooij, Jack (Student TU Delft); Meesters, G.M.H. (TU Delft ChemE/Product and Process Engineering); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering)","","2024","Horizontal stirred bed reactors are widely used in the commercial manufacturing of polypropylene. However, a comprehensive understanding of the particle dynamics in horizontal stirred bed reactors remains elusive, primarily due to the lack of detailed experimental data. In this work, we studied the influence of operating parameters on the particle flow dynamics in a laboratory-scale horizontal stirred bed reactor using single-photon emission radioactive particle tracking. The results show that the general solids flow behavior is strongly affected by both the agitator rotation speed and reactor fill level. Operation at low rotation speed and low fill level results in solids flow with poor radial and circumferential distribution due to internal bed circulation. On the contrary, at increased rotation speeds and fill levels, solids motion throughout the bed is continuous resulting in excellent solids distribution. The solids circulation was found to increase for both an increase in rotation speed and reactor fill level. The axial dispersion coefficient, on the other hand, shows a linear relation with the rotation speed, but no conclusive relation between the axial dispersion coefficient and the reactor fill level was found.","Horizontal stirred bed reactors; Multiphase reactors; Polypropylene; Radioactive particle tracking; Reactor optimization","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:9a9d9274-8ef8-453e-80b0-f3da6894e5b3","http://resolver.tudelft.nl/uuid:9a9d9274-8ef8-453e-80b0-f3da6894e5b3","Co-eigenvector Graphs","Van Mieghem, P.F.A. (TU Delft Network Architectures and Services); Jokic, I. (TU Delft Network Architectures and Services)","","2024","Except for the empty graph, we show that the orthogonal matrix X of the adjacency matrix A determines that adjacency matrix completely, but not always uniquely. The proof relies on interesting properties of the Hadamard product Ξ = X ◦ X. As a consequence of the theory, we show that irregular co-eigenvector graphs exist only if the number of nodes N ≥ 6. Coeigenvector graphs possess the same orthogonal eigenvector matrix X, but different eigenvalues of the adjacency matrix. Co-eigenvector graphs are the dual of co-spectral graphs, that share all eigenvalues of the adjacency matrix, but possess a different orthogonal eigenvector matrix. We deduce general properties of co-eigenvector graph and start to enumerate all co-eigenvector graphs on N = 6 and N = 7 nodes. Finally, we list many open problems.","graph spectra; eigenvectors; eigenvalues; co-eigenvector graphs","en","journal article","","","","","","","","","","","Network Architectures and Services","","",""
"uuid:905164f0-b023-4606-9769-1f598907fa43","http://resolver.tudelft.nl/uuid:905164f0-b023-4606-9769-1f598907fa43","Fast-charge high-voltage layered cathodes for sodium-ion batteries","Wang, Q. (TU Delft RST/Storage of Electrochemical Energy); Zhou, Dong (Helmholtz-Zentrum Berlin); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Wang, Jianlin (Chinese Academy of Sciences); Guo, Hao (China Institute of Atomic Energy); Wang, Liguang (Zhejiang University); Yao, Zhenpeng (Shanghai Jiao Tong University); Lu, Jun (Zhejiang University); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2024","Sodium-ion batteries have not only garnered substantial attention for grid-scale energy storage owing to the higher abundance of sodium compared with lithium, but also present the possibility of fast charging because of the inherently higher sodium-ion mobility. However, it remains a phenomenal challenge to achieve a combination of these merits, given the complex structural chemistry of sodium-ion oxide materials. Here we show that O3-type sodium-ion layered cathodes (for example, Na5/6Li2/27Ni8/27Mn11/27Ti6/27O2) have the potential to attain high power density, high energy density (260 Wh kg−1 at the electrode level) and long cycle life (capacity retention of 80% over 700 cycles in full cells). The design involves introduction of characteristic P3-structural motifs into an O3-type framework that serves to promote sodium-ion diffusivity and address detrimental transition metal migration and phase transition at a high state of charge. This study provides a principle for the rational design of sodium-ion layered oxide electrodes and advances the understanding of the composition–structure–property relationships of oxide cathode materials.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-15","","","RST/Storage of Electrochemical Energy","","",""
"uuid:8047abed-13d3-4766-9d1a-899644749ab1","http://resolver.tudelft.nl/uuid:8047abed-13d3-4766-9d1a-899644749ab1","Peroxygenase-Catalyzed Allylic Oxidation Unlocks Telescoped Synthesis of (1S,3R)-3-Hydroxycyclohexanecarbonitrile","Heckmann, C.M. (TU Delft BT/Biocatalysis); Bürgler, Moritz (Bisy GmbH); Paul, C.E. (TU Delft BT/Biocatalysis)","","2024","The unmatched chemo-, regio-, and stereoselectivity of enzymes renders them powerful catalysts in the synthesis of chiral active pharmaceutical ingredients (APIs). Inspired by the discovery route toward the LPA1-antagonist BMS-986278, access to the API building block (1S,3R)-3-hydroxycyclohexanecarbonitrile was envisaged using an ene reductase (ER) and alcohol dehydrogenase (ADH) to set both stereocenters. Starting from the commercially available cyclohexene-1-nitrile, a C-H oxyfunctionalization step was required to introduce the ketone functional group, yet several chemical allylic oxidation strategies proved unsuccessful. Enzymatic strategies for allylic oxidation are underdeveloped, with few examples on selected substrates with cytochrome P450s and unspecific peroxygenases (UPOs). In this case, UPOs were found to catalyze the desired allylic oxidation with high chemo- and regioselectivity, at substrate loadings of up to 200 mM, without the addition of organic cosolvents, thus enabling the subsequent ER and ADH steps in a three-step one-pot cascade. UPOs even displayed unreported enantioselective oxyfunctionalization and overoxidation of the substituted cyclohexene. After screening of enzyme panels, the final product was obtained at titers of 85% with 97% ee and 99% de, with a substrate loading of 50 mM, the ER being the limiting step. This synthetic approach provides the first example of a three-step, one-pot UPO-ER-ADH cascade and highlights the potential for UPOs to catalyze diverse enantioselective allylic hydroxylations and oxidations that are otherwise difficult to achieve.","alcohol dehydrogenase; biocatalysis; cascade; ene reductase; peroxygenase; retrosynthesis","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:4c7eaea2-61fc-479f-9532-f68d3c1e2470","http://resolver.tudelft.nl/uuid:4c7eaea2-61fc-479f-9532-f68d3c1e2470","A new approach for fast field calculation in electrostatic electron lens design and optimization","Hesam Mahmoudi Nezhad, N. (TU Delft ImPhys/Hagen group); Ghaffarian Niasar, M. (TU Delft High Voltage Technology Group); Hagen, C.W. (TU Delft ImPhys/Hagen group); Kruit, P. (TU Delft ImPhys/Hoogenboom group)","","2024","In electron optics, calculation of the electric field plays a major role in all computations and simulations. Accurate field calculation methods such as the finite element method (FEM), boundary element method and finite difference method, have been used for years. However, such methods are computationally very expensive and make the computer simulation challenging or even infeasible when trying to apply automated design of electrostatic lens systems with many free parameters. Hence, for years, electron optics scientists have been searching for a fast and accurate method of field calculation to tackle the aforementioned problem in the design and optimization of electrostatic electron lens systems. This paper presents a novel method for fast electric field calculation in electrostatic electron lens systems with reasonably high accuracy to enable the electron-optical designers to design and optimize an electrostatic lens system with many free parameters in a reasonably short time. The essence of the method is to express the off-axis potential in an axially symmetrical coordinate system in terms of derivatives of the axial potential up to the fourth order, and equate this to the potential of the electrode at that axial position. Doing this for a limited number of axial positions, we get a set of equations that can be solved to obtain the axial potential, necessary for calculating the lens properties. We name this method the fourth-order electrode method because we take the axial derivatives up to the fourth order. To solve the equations, a quintic spline approximation of the axial potential is calculated by solving three sets of linear equations simultaneously. The sets of equations are extracted from the Laplace equation and the fundamental equations that describe a quintic spline. The accuracy and speed of this method is compared with other field calculation methods, such as the FEM and second order electrode method (SOEM). The new field calculation method is implemented in design/optimization of electrostatic lens systems by using a genetic algorithm based optimization program for electrostatic lens systems developed by the authors. The effectiveness of this new field calculation method in optimizing optical parameters of electrostatic lens systems is compared with FEM and SOEM and the results are presented. It should be noted that the formulation is derived for general axis symmetrical electrostatic electron lens systems, however the examples shown in this paper are with cylindrical electrodes due to the simplicity of the implementation in the software.","","en","journal article","","","","","","","","","","","ImPhys/Hagen group","","",""
"uuid:07288470-d19d-47f7-9814-eabf228a2eab","http://resolver.tudelft.nl/uuid:07288470-d19d-47f7-9814-eabf228a2eab","Series magnetic coupled reactor saturation considerations for high voltage AC and DC power systems","Heidary, Amir (TU Delft Intelligent Electrical Power Grids); Ghaffarian Niasar, M. (TU Delft High Voltage Technology Group); Popov, M. (TU Delft Intelligent Electrical Power Grids)","","2024","The rapid increase of integrated distributed generators results in higher fault currents in the future modern grids. A remedy for the concern is employing series reactors as fault current limiters. This paper elaborates on a ferromagnetic core series reactor, which, when saturated, adversely affects the operation of the series reactor during faults. The main goal of the paper is to calculate grid and series reactor coefficients by applying a simplified power line model during a fault condition. These coefficients are the primary considerations of a series reactor design to avoid its saturation. Moreover, the study of the relationship between the reactor inductance and obtained coefficients will be carried out. The obtained results are validated by simulations performed in MATLAB Simulink.","Fault current limiter; Series reactor; Saturation region","en","journal article","","","","","","","","","","","Intelligent Electrical Power Grids","","",""
"uuid:d2f0dfb9-85c2-4c3d-9607-759315cfce58","http://resolver.tudelft.nl/uuid:d2f0dfb9-85c2-4c3d-9607-759315cfce58","Digital Twin of Calais Canal with Model Predictive Controller: A Simulation on a Real Database","Ranjbar, Roza (Institut Mines-Telecom); Segovia Castillo, P. (TU Delft Transport Engineering and Logistics); Duviella, Eric (Institut Mines-Telecom); Etienne, Lucien (Institut Mines-Telecom); Maestre, José M. (University of Seville); Camacho, Eduardo F. (University of Seville)","","2024","This paper presents the design of a model predictive control (MPC) for the Calais canal, located in the north of France for satisfactory management of the system. To estimate the unknown inputs/outputs arising from the uncontrolled pumps, a digital twin (DT) in the framework of a Matlab-SIC2 is used to reproduce the dynamics of the canal, and the real database corresponding to a period of three days is employed to evaluate the control strategy. The canal is characterized by two operating modes due to high and low tides. As a consequence of this, time-varying constraints on the use of gates must be considered, which leads to the design of two multiobjective control problems, one for the high tide and another for the low tide. Furthermore, a moving horizon estimation (MHE) strategy is used to provide the MPC with unmeasured states. The simulation results show that the different objectives are met satisfactorily.","Digital twin (DT); Inland waterways; Model predictive control (MPC); Real database; Unknown inputs/outputs","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-27","","","Transport Engineering and Logistics","","",""
"uuid:17ed518d-20f2-4147-81e8-557a9f51efd0","http://resolver.tudelft.nl/uuid:17ed518d-20f2-4147-81e8-557a9f51efd0","A linear matrix inequality approach to optimal reset control design for a class of nonlinear systems","Shahbazzadeh, Majid (Babol Noshirvani University of Technology); Sadati, S. Jalil (Babol Noshirvani University of Technology); Hassan HosseinNia, S. (TU Delft Mechatronic Systems Design)","","2024","In this article, the problem of the optimal reset control design for Lipschitz nonlinear systems is addressed. The reset controller includes a base linear controller and a reset law that enforces resets to the controller states. The reset law design is strongly dependent on the appropriate design of the base controller. For this reason, in this article, the base controller and reset law are simultaneously designed. More precisely, an optimal dynamic output feedback is considered as the base controller which minimizes the upper bound of a quadratic performance index, and a reset law is used to improve the transient response of the closed-loop system. This design is done in a full offline procedure. The problem is transformed into a set of linear matrix inequalities (LMIs), and the reset controller is obtained by solving an offline LMI optimization problem. Finally, two examples are presented to illustrate the effectiveness and validity of the proposed method.","dynamic output feedback; linear matrix inequalities; Lipschitz condition; reset control systems; reset law","en","journal article","","","","","","","","2024-07-19","","","Mechatronic Systems Design","","",""
"uuid:68cbed6b-cf92-413a-8454-bc2c95ec30e2","http://resolver.tudelft.nl/uuid:68cbed6b-cf92-413a-8454-bc2c95ec30e2","A bi-level framework for heterogeneous fleet sizing of ride-hailing services considering an approximated mixed equilibrium between automated and non-automated traffic","Fan, Q. (TU Delft Discrete Mathematics and Optimization; TU Delft Transport and Planning); van Essen, J.T. (TU Delft Discrete Mathematics and Optimization); Correia, Gonçalo (TU Delft Transport and Planning)","","2024","Ride-hailing companies will face the emergence and gradual expansion of AVs-only zones in urban areas where only automated vehicles (AVs) are allowed to circulate. When owning a mixed fleet (automated and conventional taxis), a ride-hailing company has to determine the optimal fleet size as a function of the gradually expanding coverage of AVs-only zones while taking into account interactions with privately-owned human-driven vehicles. To model this problem, we propose a bi-level framework in which the lower level captures the mixed routing behaviour of the vehicles and the endogenous traffic congestion, and the upper level determines fleet sizes to maximise profit. A parallel genetic algorithm is introduced to solve this bi-level framework, which is embedded with a tailored algorithm for solving the lower-level model. Numerical experiments are conducted on instances based on a small network and the network of the city of Delft, The Netherlands, to demonstrate the performance of the proposed solution method and investigate the impacts of AVs-only zones on traffic and ride-hailing operations. Results indicate that the fleet size of automated taxis increases nonlinearly with the expansion of the AVs-only zone while that of conventional taxis decreases as demand shifts from human-driven vehicles to automated taxis. The fleet size decision depends heavily on the fleet's cost structure, the location and the distribution of parking depots. Furthermore, the existence of an AVs-only zone leads to detours for human-driven vehicles in the early stages, but it will bring major benefits by reducing congestion as its size increases.","Routing; Fleet sizing; Approximated mixed equilibrium; AVs-only zone; e-hailing services","en","journal article","","","","","","","","","","","Discrete Mathematics and Optimization","","",""
"uuid:64c38066-d331-425b-b8a0-710bbc1cfcf5","http://resolver.tudelft.nl/uuid:64c38066-d331-425b-b8a0-710bbc1cfcf5","Multi-wavelength Raman microscopy of nickel-based electron transport in cable bacteria","Smets, Bent (Universiteit Antwerpen); Boschker, H.T.S. (TU Delft BT/Environmental Biotechnology; Universiteit Antwerpen); Wetherington, Maxwell T. (Pennsylvania State University); Lelong, Gérald (Sorbonne Université); Hidalgo-Martinez, Silvia (Universiteit Antwerpen); Polerecky, Lubos (Universiteit Utrecht); Nuyts, Gert (Universiteit Antwerpen); De Wael, Karolien (Universiteit Antwerpen); Meysman, F.J.R. (TU Delft BT/Environmental Biotechnology; Universiteit Antwerpen)","","2024","Cable bacteria embed a network of conductive protein fibers in their cell envelope that efficiently guides electron transport over distances spanning up to several centimeters. This form of long-distance electron transport is unique in biology and is mediated by a metalloprotein with a sulfur-coordinated nickel (Ni) cofactor. However, the molecular structure of this cofactor remains presently unknown. Here, we applied multi-wavelength Raman microscopy to identify cell compounds linked to the unique cable bacterium physiology, combined with stable isotope labeling, and orientation-dependent and ultralow-frequency Raman microscopy to gain insight into the structure and organization of this novel Ni-cofactor. Raman spectra of native cable bacterium filaments reveal vibrational modes originating from cytochromes, polyphosphate granules, proteins, as well as the Ni-cofactor. After selective extraction of the conductive fiber network from the cell envelope, the Raman spectrum becomes simpler, and primarily retains vibrational modes associated with the Ni-cofactor. These Ni-cofactor modes exhibit intense Raman scattering as well as a strong orientation-dependent response. The signal intensity is particularly elevated when the polarization of incident laser light is parallel to the direction of the conductive fibers. This orientation dependence allows to selectively identify the modes that are associated with the Ni-cofactor. We identified 13 such modes, some of which display strong Raman signals across the entire range of applied wavelengths (405–1,064 nm). Assignment of vibrational modes, supported by stable isotope labeling, suggest that the structure of the Ni-cofactor shares a resemblance with that of nickel bis(1,2-dithiolene) complexes. Overall, our results indicate that cable bacteria have evolved a unique cofactor structure that does not resemble any of the known Ni-cofactors in biology.","Raman microscopy; cable bacteria; nickel cofactor; metalloprotein; long-distance electron transport","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:1721cfd3-d50c-42c6-a62b-ab40af15e341","http://resolver.tudelft.nl/uuid:1721cfd3-d50c-42c6-a62b-ab40af15e341","On spatially correlated observations in importance sampling methods for subsidence estimation","Kim, S.S.R. (TU Delft Reservoir Engineering); Vossepoel, F.C. (TU Delft Reservoir Engineering)","","2024","The particle filter is a data assimilation method based on importance sampling for state and parameter estimation. We apply a particle filter in two different quasi-static experiments with models of subsidence caused by a compacting reservoir. The first model considers uncorrelated model state variables and observations, with observed subsidence resulting from a single source of strain. In the second model, subsidence is a summation of subsidence contributions from multiple sources which causes spatial dependencies and correlations in the observed subsidence field. Assimilating these correlated subsidence fields may trigger weight collapse. With synthetic tests, we show in a model of subsidence with 50 independent state variables and spatially correlated subsidence a minimum of 1013 particles are required to have information in the posterior distribution identical to that in a model with 50 independent and spatially uncorrelated observations. Spatial correlations cause an information loss which can be quantified with mutual information. We illustrate how a stronger spatial correlation results in lower information content in the posterior and we empirically derive the required ensemble size for the importance sampling to remain effective. We furthermore illustrate how this loss of information is reflected in the log likelihood, and how this depends on the number of model state variables. Based on these empirical results, we propose criteria to evaluate the required ensemble size in data assimilation of spatially correlated observation fields.","Ensemble size; Information theory; Particle method; Reservoir; Subsidence; Weight collapse","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:9af93419-2648-4a16-89d8-e34aa863e637","http://resolver.tudelft.nl/uuid:9af93419-2648-4a16-89d8-e34aa863e637","A fast and robust constraint-based online re-optimization approach for automated online adaptive intensity modulated proton therapy in head and neck cancer","Oud, Michelle (Erasmus MC; Holland Particle Therapy Centre); Breedveld, Sebastiaan (Erasmus MC); Rojo-Santiago, Jesús (Erasmus MC; Holland Particle Therapy Centre); Giżyńska, Marta Krystyna (Holland Particle Therapy Centre); Kroesen, Michiel (Erasmus MC); Habraken, S.J.M. (Erasmus MC; Holland Particle Therapy Centre); Perko, Z. (TU Delft RST/Reactor Physics and Nuclear Materials); Heijmen, Ben (Erasmus MC); Hoogeman, M.S. (TU Delft RST/Medical Physics & Technology; Erasmus MC; Holland Particle Therapy Centre)","","2024","Objective. In head-and-neck cancer intensity modulated proton therapy, adaptive radiotherapy is currently restricted to offline re-planning, mitigating the effect of slow changes in patient anatomies. Daily online adaptations can potentially improve dosimetry. Here, a new, fully automated online re-optimization strategy is presented. In a retrospective study, this online re-optimization approach was compared to our trigger-based offline re-planning (offlineTB re-planning) schedule, including extensive robustness analyses. Approach. The online re-optimization method employs automated multi-criterial re-optimization, using robust optimization with 1 mm setup-robustness settings (in contrast to 3 mm for offlineTB re-planning). Hard planning constraints and spot addition are used to enforce adequate target coverage, avoid prohibitively large maximum doses and minimize organ-at-risk doses. For 67 repeat-CTs from 15 patients, fraction doses of the two strategies were compared for the CTVs and organs-at-risk. Per repeat-CT, 10.000 fractions with different setup and range robustness settings were simulated using polynomial chaos expansion for fast and accurate dose calculations. Main results. For 14/67 repeat-CTs, offlineTB re-planning resulted in <50% probability of D98% ≥ 95% of the prescribed dose (Dpres) in one or both CTVs, which never happened with online re-optimization. With offlineTB re-planning, eight repeat-CTs had zero probability of obtaining D98% ≥ 95%Dpres for CTV7000, while the minimum probability with online re-optimization was 81%. Risks of xerostomia and dysphagia grade ≥ II were reduced by 3.5 ± 1.7 and 3.9 ± 2.8 percentage point [mean ± SD] (p < 10−5 for both). In online re-optimization, adjustment of spot configuration followed by spot-intensity re-optimization took 3.4 min on average. Significance. The fast online re-optimization strategy always prevented substantial losses of target coverage caused by day-to-day anatomical variations, as opposed to the clinical trigger-based offline re-planning schedule. On top of this, online re-optimization could be performed with smaller setup robustness settings, contributing to improved organs-at-risk sparing.","intensity modulated proton therapy (IMPT); daily online adaptive radiotherapy using dose restoration; head-and-neck cancer; inter-fraction anatomy variation; automated treatment planning","en","journal article","","","","","","","","","","","RST/Reactor Physics and Nuclear Materials","","",""
"uuid:e9f85596-f8eb-415e-873f-d62683515103","http://resolver.tudelft.nl/uuid:e9f85596-f8eb-415e-873f-d62683515103","Where does the AMOC peak? Assesssing regional variations in North Atlantic Overturning from GLORYS12 ","Katsman, C.A. (TU Delft Environmental Fluid Mechanics); Oldenhuis, D.J. (TU Delft Civil Engineering & Geosciences); Vermeulen, D.H.A. (TU Delft Environmental Fluid Mechanics); Gelderloos, R. (TU Delft Environmental Fluid Mechanics)","","2024","The Atlantic Meridional Overturning Circulation (AMOC) transports vast amounts of heat to high latitudes, and is largely responsible for Western Europe’s relatively mild climate. Climate models project the AMOC will weaken substantially over the 21st century, which impacts weather, climate, sea level and the oceanic carbon cycle. In many studies, the AMOC state is described in a condensed two-dimensional view or even by means of a single metric, which leaves many aspects of its complex 3D-structure underexposed. By revealing the sharp contrast in overturning strength between the western and eastern subpolar gyre (SPG), the recent OSNAP observations emphasized the importance of considering the AMOC in 3D.
In this study, we explore this further by analyzing the characteristics of the overturning in density space in the North Atlantic SPG on a regional scale, and over time periods ranging from seasons to decades. For this, we use model data from the high-resolution GLORYS12 reanalysis, spanning the period 1993-2020. Following the approach applied in OSNAP, the overturning is assessed from alongstream changes in boundary current transport in specific density classes. This analysis is performed for the entire SPG, for its major basins (Iceland Basin, Irminger Sea, and Labrador Sea) and for smaller segments along the boundary currents, thus providing detailed insights in variations of the overturning varies along the entire SPG boundary.
The mean overturning from GLORYS12 for 1993-2020 is 23.8 Sv, distributed as 41%, 29%, and 30% for the Iceland Basin, Irminger Sea, and Labrador Sea respectively, and peaking at increasingly higher densities in alongstream direction. Within each basin, a pronounced seasonal cycle can be identified, with the maximum overturning occurring in March and the minimum in September. Over the entire reanalysis period, the overturning strength in both the Iceland Basin and Irminger Sea exhibits a weak decreasing trend, whereas the Labrador Sea displays a weak increasing trend.
The subdivision in shorter segments reveals large spatial differences in overturning, both with regard to its overall strength and its distribution over density classes. However, these outcomes are less robust than the analyses on the scale of the major basins, as the flow is highly variable and numerical uncertainties associated with offline overturning calculations become more prominent.
Further research is needed to properly interpret these regional variations, and thereby improve our understanding of the AMOC dynamics and its sensitivity to changing oceanic and atmospheric forcing conditions. Linking them to local processes known to govern the overturning (i.e., formation of dense waters in the interior of marginal seas and their export, formation of dense waters within the boundary current system itself and the exchange of waters via overflows) seems a viable route.","","en","abstract","","","","","","","","","Civil Engineering & Geosciences","","Environmental Fluid Mechanics","","",""
"uuid:e84fdf90-e77b-4e70-94b6-350e55e17d83","http://resolver.tudelft.nl/uuid:e84fdf90-e77b-4e70-94b6-350e55e17d83","Guest editorial: Integrated corporate real estate and facilities management strategies","van der Voordt, Theo (TU Delft Real Estate Management)","","2024","Seven years ago I wrote a paper about the growing connections between Corporate Real Estate Management (CREM) and Facilities Management (FM) (Van der Voordt, 2017). Last year I coauthored the third edition of a Dutch book on Accommodating People, in which we share insights from practice and research about the main components of CREM/FM strategies and how to implement these strategies in briefing processes, business cases, new building projects and management of buildings-in use (Hoendervanger et al., 2022). In this book, connecting CREM and FM with other disciplines like human resource management, information technology and finance and control is a key concept as well. Due to a growing attention to balancing business needs, end-user needs and societal needs, incorporating the required expertise from different disciplines such as environmental psychology, ergonomics, sustainability, circular building and so on is also highly relevant. [...]","","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-27","","","Real Estate Management","","",""
"uuid:ea542d00-1a25-46eb-ac0b-9ab5126f023e","http://resolver.tudelft.nl/uuid:ea542d00-1a25-46eb-ac0b-9ab5126f023e","Dynamic thermal model of passenger aircraft for the estimation of the cabin cooling and heating requirements","Giuffré, A. (TU Delft Flight Performance and Propulsion); Colonna, Piero (TU Delft Flight Performance and Propulsion); de Servi, C.M. (TU Delft Flight Performance and Propulsion; Flemish Institute for Technological Research)","","2024","The Environmental Control System (ECS) of passenger aircraft is the main consumer of non-propulsive power aboard. A computationally efficient and accurate thermal model of the fuselage is needed for future sustainable aircraft to address ECS preliminary sizing and control design, as the ECS should be re-designed to exploit possible synergies with other thermal management systems on board. Differently from previous works, the present aircraft thermal model is extensively documented and released open-source. Moreover, it is completely based on first principles and the acausal modeling paradigm. It results that the model is scalable, easily extendable, and allows for the estimation of the aircraft thermal loads given limited information about its configuration and flight mission. The predictive capabilities of the model have been assessed by comparing the thermodynamic state estimated at the pack discharge for three ECS operating points of an Airbus A320 with data provided by the manufacturer. The maximum deviation is limited to 2.4 K and 4.5 kPa. The validated thermal model has been used to compute the operating envelope of the A320 ECS, showing that the air supply requirements vary substantially with ambient conditions and flight phases. This calls for a multi-point design strategy when assessing novel ECS configurations.","Dynamic simulation; Environmental control system (ECS); Fuselage thermal model; Modelica; Thermal management system","en","journal article","","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:dd163f10-70c5-4094-8e88-3ea6b754651c","http://resolver.tudelft.nl/uuid:dd163f10-70c5-4094-8e88-3ea6b754651c","ApHMM: Accelerating Profile Hidden Markov Models for Fast and Energy-efficient Genome Analysis","Firtina, Can (ETH Zürich); Pillai, Kamlesh (Intel Labs); Kalsi, Gurpreet S. (Intel Labs); Suresh, Bharathwaj (Intel Labs); Cali, Damla Senol (Carnegie Mellon University); Kim, Jeremie S. (ETH Zürich); Shahroodi, Taha (TU Delft Computer Engineering); Cavlak, Meryem Banu (ETH Zürich); Lindegger, Joël (ETH Zürich)","","2024","Profile hidden Markov models (pHMMs) are widely employed in various bioinformatics applications to identify similarities between biological sequences, such as DNA or protein sequences. In pHMMs, sequences are represented as graph structures, where states and edges capture modifications (i.e., insertions, deletions, and substitutions) by assigning probabilities to them. These probabilities are subsequently used to compute the similarity score between a sequence and a pHMM graph. The Baum-Welch algorithm, a prevalent and highly accurate method, utilizes these probabilities to optimize and compute similarity scores. Accurate computation of these probabilities is essential for the correct identification of sequence similarities. However, the Baum-Welch algorithm is computationally intensive, and existing solutions offer either software-only or hardware-only approaches with fixed pHMM designs. When we analyze state-of-the-art works, we identify an urgent need for a flexible, high-performance, and energy-efficient hardware-software co-design to address the major inefficiencies in the Baum-Welch algorithm for pHMMs. We introduce ApHMM, the first flexible acceleration framework designed to significantly reduce both computational and energy overheads associated with the Baum-Welch algorithm for pHMMs. ApHMM employs hardware-software co-design to tackle the major inefficiencies in the Baum-Welch algorithm by (1) designing flexible hardware to accommodate various pHMM designs, (2) exploiting predictable data dependency patterns through on-chip memory with memoization techniques, (3) rapidly filtering out unnecessary computations using a hardware-based filter, and (4) minimizing redundant computations. ApHMM achieves substantial speedups of 15.55×–260.03×, 1.83×–5.34×, and 27.97× when compared to CPU, GPU, and FPGA implementations of the Baum-Welch algorithm, respectively. ApHMM outperforms state-of-the-art CPU implementations in three key bioinformatics applications: (1) error correction, (2) protein family search, and (3) multiple sequence alignment, by 1.29×–59.94×, 1.03×–1.75×, and 1.03×–1.95×, respectively, while improving their energy efficiency by 64.24×–115.46×, 1.75×, and 1.96×.","Bioinformatics; genomics; profile hidden markov models; the Baum-Welch Algorithm","en","journal article","","","","","","","","","","","Computer Engineering","","",""
"uuid:6397b54e-27d3-4f33-84ca-f2eff324b71d","http://resolver.tudelft.nl/uuid:6397b54e-27d3-4f33-84ca-f2eff324b71d","Initiation and evolution of systemic innovations: Patterns and interactions in the emergence of additive manufacturing technologies","Luomaranta, Toni (WU Wien); Martinsuo, Miia (University of Turku; Tampere University); Ortt, J.R. (TU Delft Economics of Technology and Innovation; Erasmus Universiteit Rotterdam)","","2024","Technological innovations are becoming increasingly systemic in the complex and interconnected world. The initiation and evolution of systemic innovations take time and include numerous challenges, and the mechanisms through which systemic innovations emerge in the interaction between different technologies represent a research gap. This paper explores the emergence of ceramic additive manufacturing as an example of a systemic manufacturing technology innovation. We implemented an event history analysis of four ceramic-material additive manufacturing technologies. We traced the initiation and evolution paths of each of the four technologies over time and showed a pattern of activities within and across the technologies. The study contributes by revealing that systemic innovations emerge as a result of parallel and sequential development paths of within-technology system components as well as the interaction between multiple technologies. The timing of the coalescing development paths of the system components and technologies appears crucial but serendipitous instead of coordinated. The findings open new pathways for speeding up the emergence of systemic innovations and forthcoming research to support the evolution of additive manufacturing.","additive manufacturing; event history analysis; systemic innovation; technology evolution","en","journal article","","","","","","","","","","","Economics of Technology and Innovation","","",""
"uuid:6fc368af-b276-400c-84c7-7b891cec508f","http://resolver.tudelft.nl/uuid:6fc368af-b276-400c-84c7-7b891cec508f","Risk vs. restriction—An investigation of capacity-limitation based congestion management in electric distribution grids","Hennig, R.J. (TU Delft Energie and Industrie); De Vries, Laurens (TU Delft Energie and Industrie); Tindemans, Simon H. (TU Delft Intelligent Electrical Power Grids)","","2024","Electrification of energy end-uses brings an increasing load on electric distribution grids with load peaks that can cause network congestion. However, many new end-uses like electric vehicles, heat pumps, and electrified industrial processes have some flexibility to move their power consumption away from peak times. Congestion management mechanisms can harness this flexibility. This paper investigates congestion management mechanisms based on limited available network capacity for flexible loads during peak times. A case study discusses and investigates real-world examples of such mechanisms from proposals in Germany and the Netherlands. They differ concerning the lead time at which the capacity limitation is announced, with options from near real-time and day-ahead to long-term. These mechanisms are suited to remove network congestion, but there are significant trade-offs concerning the lead time. A shorter lead time leaves more room for using the network during non-congested times but creates a risk of curtailment for end-users, which may come with associated balancing and re-procurement costs. Longer lead times give more certainty on network access conditions but often restrict network usage even when there is no network congestion.","distribution network; Load control; congestion management; Capacity subscription; Flexibility; Electricity","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:8711ee3f-3ad0-43e2-9f20-7d6c101ef3c0","http://resolver.tudelft.nl/uuid:8711ee3f-3ad0-43e2-9f20-7d6c101ef3c0","Improved Anomaly Detection and Localization Using Whitening-Enhanced Autoencoders","Wang, C. (TU Delft Intelligent Electrical Power Grids); Tindemans, Simon H. (TU Delft Intelligent Electrical Power Grids); Palensky, P. (TU Delft Intelligent Electrical Power Grids)","","2024","Anomaly detection is of considerable significance in engineering applications, such as the monitoring and control of large-scale energy systems. This article investigates the ability to accurately detect and localize the source of anomalies, using an autoencoder neural network-based detector. Correlations between residuals are identified as a source of misclassifications, and whitening transformations that decorrelate input features and/or residuals are analyzed as a potential solution. For two use cases, regarding spatially distributed wind power generation and temporal profiles of electricity consumption, the performance of various data processing combinations was quantified. Whitening of the input data was found to be most beneficial for accurate detection, with a slight benefit for the combined whitening of inputs and residuals. For localization of anomalies, whitening of residuals was preferred, and the best performance was obtained using standardization of the input data and whitening of the residuals using the zero-phase component analysis (ZCA) or zero-phase component analysis-correlation (ZCA-cor) whitening matrix with a small additional offset.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-03","","","Intelligent Electrical Power Grids","","",""
"uuid:ed0e2cc7-4d89-4a5a-9783-f95a3bf9abba","http://resolver.tudelft.nl/uuid:ed0e2cc7-4d89-4a5a-9783-f95a3bf9abba","DBHC: Discrete Bayesian HMM Clustering","Budel, G.J.A. (TU Delft Network Architectures and Services); Frasincar, Flavius (Erasmus Universiteit Rotterdam); Boekestijn, David (Erasmus Universiteit Rotterdam)","","2024","Sequence data mining has become an increasingly popular research topic as the availability of data has grown rapidly over the past decades. Sequence clustering is a type of method within this field that is in high demand in the industry, but the sequence clustering problem is non-trivial and, as opposed to static cluster analysis, interpreting clusters of sequences is often difficult. Using Hidden Markov Models (HMMs), we propose the Discrete Bayesian HMM Clustering (DBHC) algorithm, an approach to clustering discrete sequences by extending a proven method for continuous sequences. The proposed algorithm is completely self-contained as it incorporates both the search for the number of clusters and the search for the number of hidden states in each cluster model in the parameter inference. We provide a working example and a simulation study to explain and showcase the capabilities of the DBHC algorithm. A case study illustrates how the hidden states in a mixture of HMMs can aid the interpretation task of a sequence cluster analysis. We conclude that the algorithm works well as it provides well-interpretable clusters for the considered application.","Graphical models; Mixture hidden Markov models; Probability smoothing; Sequence clustering; Sequence data mining","en","journal article","","","","","","","","","","","Network Architectures and Services","","",""
"uuid:5f8d76d8-394d-4265-906a-c0c68a9f16f8","http://resolver.tudelft.nl/uuid:5f8d76d8-394d-4265-906a-c0c68a9f16f8","Frequency-domain framework for floating installation of wind-turbine towers","Fidalgo Domingos, D.A. (TU Delft Team Jan-Willem van Wingerden); Wellens, P.R. (TU Delft Ship Hydromechanics and Structures); van Wingerden, J.W. (TU Delft Team Jan-Willem van Wingerden)","","2024","As a result of more stable wind conditions and the depletion of near-shore locations, wind farms are moving farther offshore into deeper waters, challenging the current limits of offshore heavy-lift operations. This paper presents and verifies a novel frequency-domain framework to perform extensive site-specific analysis, of floating installations of wind-turbine towers, subjected to wind and wave loads. The versatility and potential of this framework is demonstrated with a case-study of a wind farm near the coast of Portugal. The results lead to the following conclusions: (1) Only considering beam-seas the yearly workability is 39 %; (2) Workability is mostly limited by wave loads; (3) Tower motions tend to decrease with tower size and are not significantly affected by hook-tower distance (sling length); and finally, (4) In this case-study the most contributing frequencies for tower motions are 0.3 and 0.4 rad/s, corresponding mainly to the first pendulation mode.","Dynamic error budgeting; Heavy lift; Offshore wind; Sensitivity analysis; Stochastic disturbances; Workability analysis","en","journal article","","","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:6696a88c-81d3-4e74-9bd0-8941561b57fa","http://resolver.tudelft.nl/uuid:6696a88c-81d3-4e74-9bd0-8941561b57fa","Rights and Wrongs in Talk of Mind-Reading Technology","Rainey, S. (TU Delft Ethics & Philosophy of Technology)","","2024","This article examines the idea of mind-reading technology by focusing on an interesting case of applying a large language model (LLM) to brain data. On the face of it, experimental results appear to show that it is possible to reconstruct mental contents directly from brain data by processing via a chatGPT-like LLM. However, the author argues that this apparent conclusion is not warranted. Through examining how LLMs work, it is shown that they are importantly different from natural language. The former operates on the basis of nonrational data transformations based on a large textual corpus. The latter has a rational dimension, being based on reasons. Using this as a basis, it is argued that brain data does not directly reveal mental content, but can be processed to ground predictions indirectly about mental content. The author concludes that this is impressive but different in principle from technology-mediated mind reading. The applications of LLM-based brain data processing are nevertheless promising for speech rehabilitation or novel communication methods.","brain data; chatGPT; fMRI; large language models; mind reading; reasons","en","journal article","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:901f5688-0010-4467-930f-69f6596e45b4","http://resolver.tudelft.nl/uuid:901f5688-0010-4467-930f-69f6596e45b4","Capturing experts’ knowledge in heritage planning enhanced by AI: A case study of windcatchers in Yazd, Iran","Foroughi, M. (TU Delft Heritage & Architecture); de Andrade, Bruno (TU Delft Heritage & Architecture); Pereira Roders, A. (TU Delft Heritage & Architecture)","","2024","Experts have always played an important role in heritage planning, practice, and theory. There is a wealth of literature published every year regarding heritage and its cultural significance. Experts also contribute to heritage planning and developing policy documents. Still, literature is rarely used as a source of primary research to systematically reveal and compare experts’ opinions on the cultural significance of built heritage. Analyzing them as a whole is costly and time-consuming, especially on built heritage, when much has been written about. While the automation of methods has proven to mitigate such restrictions in other fields, as digital humanities, their application in heritage planning, practice, and theory is still scarce. Hence, this paper aims to investigate the potentials of AI models (e.g., multi label text classification) in analyzing scientific documents, revealing the cultural significance of built heritage, values and attributes. This was done to better understand the similarities and differences between the experts’ opinions. Yazd, Iran, is taken a case study, with a particular focus on windcatchers, a key attribute conveying cultural significance, of outstanding universal value, due to its inscription on the UNESCO World Heritage List. This paper has three subsequent phases: 1) state of the art on the application of AI in heritage planning; 2) methodology of data collection and data analysis related to coding values and attributes of windcatchers, addressed in relevant documents; 3) preliminary findings on the experts’ opinions over values and attributes of windcatchers. Results contribute to the scientific discussion, revealing the cultural significance of windcatchers of Yazd from experts’ point of view. Besides, the potential of AI for heritage planning is revealed in terms of (de)coding and measuring the cultural significance of built heritage from the available documents, showing the opinions of experts with various backgrounds. This model can be applied to other key attributes in Yazd and other case studies and scales to support heritage planning, practice, and theory.","Attribute; Cultural significance; Expert; Natural language processing; Text classification; Value","en","journal article","","","","","","","","","","","Heritage & Architecture","","",""
"uuid:0e199283-d6e2-4a02-8231-8d63dcfdbed3","http://resolver.tudelft.nl/uuid:0e199283-d6e2-4a02-8231-8d63dcfdbed3","Examining green space characteristics for social cohesion and mental health outcomes: A sensitivity analysis in four European cities","Cardinali, M. (TU Delft Heritage & Architecture; TH OWL); Beenackers, Mariëlle A. (Erasmus MC); Fleury-Bahi, Ghozlane (Université de Nantes; L'Institut de Recherche en Sciences et Techniques de la Ville (CNRS FR2488)); Bodénan, Philippe (Conseil de Développement de Nantes Métropole); Petrova, Milena Tasheva (University of Architecture, Civil Engineering and Geodesy); van Timmeren, A. (TU Delft Environmental Technology and Design); Pottgiesser, U. (TU Delft Heritage & Architecture; TH OWL)","","2024","Introduction: In recent decades, there has been a rise in mental illnesses. Community infrastructures are increasingly acknowledged as important for sustaining good mental health. Moreover, green spaces are anticipated to offer advantages for both mental health and social cohesion. However, the mediating pathway between green space, social cohesion and mental health and especially the proximity and characteristics of green spaces that trigger these potential effects remain of interest. Methods: We gathered data from 1365 individuals on self-reported social cohesion and mental health across four satellite districts in European cities: Nantes (France), Porto (Portugal), Sofia (Bulgaria), and Høje-Taastrup (Denmark). Green space data from OpenStreetMap was manually adjusted using the PRIGSHARE guidelines. We used the AID-PRIGSHARE tool to generate 7 indicators about green space characteristics measured in distances from 100–1500 m, every 100 m. This resulted in 105 different green space variables that we tested in a single mediation model with structural equation modelling. Results: Accessible greenness (900–1400 m), accessible green spaces (900–1500 m), accessible green space corridors (300–800 m), accessible total green space (300−800), and mix of green space uses (700–1100 m) were significantly associated with social cohesion and indirectly with mental health. Green corridors also showed negative indirect and direct associations with mental health in larger distances. Surrounding greenness and the quantity of green space uses were not associated with social cohesion nor indirectly with mental health. We also observed no positive direct associations between any green space variable in any distance to mental health. Conclusions: Our results suggest that accessibility, connectivity, mix of use and proximity are key characteristics that drive the relationship between green spaces, social cohesion and mental health. This gives further guidance to urban planners and decision-makers on how to design urban green spaces to foster social cohesion and improve mental health.","Green space; Mediation; Social cohesion; Structural equation modelling; Well-being","en","journal article","","","","","","","","","","","Heritage & Architecture","","",""
"uuid:259572c1-f79a-4351-87d3-02efdbd20ee8","http://resolver.tudelft.nl/uuid:259572c1-f79a-4351-87d3-02efdbd20ee8","Kirkendall effect-induced uniform stress distribution stabilizes nickel-rich layered oxide cathodes","Gao, Ziyao (Tsinghua University); Zhao, C. (Tsinghua University); Zhou, Kai (Tsinghua University); Wu, Junru (Tsinghua University); Tian, Yao (Tsinghua University); Deng, Xianming (Tsinghua University); Zhang, Lihan (Tsinghua University); Lin, Kui (Tsinghua University); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2024","Nickel-rich layered oxide cathodes promise ultrahigh energy density but is plagued by the mechanical failure of the secondary particle upon (de)lithiation. Existing approaches for alleviating the structural degradation could retard pulverization, yet fail to tune the stress distribution and root out the formation of cracks. Herein, we report a unique strategy to uniformize the stress distribution in secondary particle via Kirkendall effect to stabilize the core region during electrochemical cycling. Exotic metal/metalloid oxides (such as Al2O3 or SiO2) is introduced as the heterogeneous nucleation seeds for the preferential growth of the precursor. The calcination treatment afterwards generates a dopant-rich interior structure with central Kirkendall void, due to the different diffusivity between the exotic element and nickel atom. The resulting cathode material exhibits superior structural and electrochemical reversibility, thus contributing to a high specific energy density (based on cathode) of 660 Wh kg−1 after 500 cycles with a retention rate of 86%. This study suggests that uniformizing stress distribution represents a promising pathway to tackle the structural instability facing nickel-rich layered oxide cathodes.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:b933dc9b-0f6a-4084-bce8-1945010a7cb0","http://resolver.tudelft.nl/uuid:b933dc9b-0f6a-4084-bce8-1945010a7cb0","Design of a Majorana trijunction","Luna, Juan Daniel Torres (Student TU Delft); Rangaswamy Kuppuswamy, S.K. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft); Akhmerov, A.R. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft)","","2024","Braiding of Majorana states demonstrates their non-Abelian exchange statistics. One implementation of braiding requires control of the pairwise couplings between all Majorana states in a trijunction device. To have adiabaticity, a trijunction device requires the desired pair coupling to be sufficiently large and the undesired couplings to vanish. In this work, we design and simulate a trijunction device in a two-dimensional electron gas with a focus on the normal region that connects three Majorana states. We use an optimisation approach to find the operational regime of the device in a multi-dimensional voltage space. Using the optimization results, we simulate a braiding experiment by adiabatically coupling different pairs of Majorana states without closing the topological gap. We then evaluate the feasibility of braiding in a trijunction device for different shapes and disorder strengths.","See also, Online presentation recording","en","journal article","","","","","","","","","","","QN/Akhmerov Group","","",""
"uuid:0d0b5348-b86d-4c50-aa76-cb5555e158bd","http://resolver.tudelft.nl/uuid:0d0b5348-b86d-4c50-aa76-cb5555e158bd","Thermal and alkaline pre-treatments of inoculum halt methanogenesis and enable cheese whey valorization by batch acidogenic fermentation","Almeida Benalcazar, E.F. (TU Delft BT/Bioprocess Engineering; University of Campinas); Mondini, Camille (Student TU Delft); Bruant, Guillaume (National Research Council Canada); Tremblay, Julien (National Research Council Canada); Weissbrodt, D.G. (TU Delft BT/Environmental Biotechnology; Norwegian University of Science and Technology (NTNU)); Mockaitis, Gustavo (University of Campinas)","","2024","BACKGROUND: Carboxylates such as volatile fatty acids (VFA) can be produced by acidogenic fermentation (AF) of dairy wastes including cheese whey, a massive residue produced at 160.67 million m3 of which 42% are not valorized and impact the environment. In mixed-culture fermentations, selection pressures can favor AF and halt methanogenesis. In this study, inoculum pre-treatment was evaluated as a selective pressure for AF demineralized cheese whey in batches. Alkaline (NaOH, pH 8.0, 6 h) and thermal (90 °C for 5 min, ice-bath until 23 °C) pre-treatments were tested with batch operations runs at initial pH 7.0 and 9.0, food-to-microorganism (F/M) ratios of 0.5 to 4.0 g COD g−1 VS, and under pressurized (P) and nonpressurized (NP) headspace, in experiments duplicated in two different research institutes. RESULTS: Acetic acid was highly produced on both Unicamp and TU Delft samples (1.36 and 1.40 g CODAcOH L−1, respectively), at the expense of methanogenesis by combining a thermal pre-treatment of inoculum with a NP batch operation started at pH 9.0. Microbial communities comprising VFA and alcohol producers, such as Clostridium, Fonticella and Intestinimonas, and fermenters such as Longilinea and Leptolinea. The lipid-accumulating Candidatus microthrix was observed in both bulk material and foam. Despite the absence of methane production, Methanosaeta were detected within the microbial community. An F/M ratio of 0.5 g COD g−1 VS led to the best VFA production of 1769.4 mg L−1. CONCLUSION: Overall, inoculum thermal pre-treatment, initial pH 9.0 and NP headspace acted as a selective pressure for halting methanogenesis and producing VFAs, valorizing cheese whey via batch acidogenic fermentation.","acidogenic fermentation; alkaline; cheese whey; physicochemical pre-treatments; thermal; volatile fatty acids","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-31","","","BT/Bioprocess Engineering","","",""
"uuid:1be668b5-1296-42c9-92ec-5928a0103e5e","http://resolver.tudelft.nl/uuid:1be668b5-1296-42c9-92ec-5928a0103e5e","Quantifying non-stabilizerness via information scrambling","Ahmadi, A. (TU Delft QN/Greplová Lab; Kavli institute of nanoscience Delft); Greplová, E. (TU Delft QN/Greplová Lab; Kavli institute of nanoscience Delft)","","2024","The advent of quantum technologies brought forward much attention to the theoretical characterization of the computational resources they provide. A method to quantify quantum resources is to use a class of functions called magic monotones and stabilizer entropies, which are, however, notoriously hard and impractical to evaluate for large system sizes. In recent studies, a fundamental connection between information scrambling, the magic monotone mana and 2-Renyi stabilizer entropy was established. This connection simplified magic monotone calculation, but this class of methods still suffers from exponential scaling with respect to the number of qubits. In this work, we establish a way to sample an out-of-time-order correlator that approximates magic monotones and 2-Renyi stabilizer entropy. We numerically show the relation of these sampled correlators to different non-stabilizerness measures for both qubit and qutrit systems and provide an analytical relation to 2-Renyi stabilizer entropy. Furthermore, we put forward and simulate a protocol to measure the monotonic behaviour of magic for the time evolution of local Hamiltonians.","","en","journal article","","","","","","","","","","","QN/Greplová Lab","","",""
"uuid:0c42da05-0eb0-48be-9a0d-3b167135eeb7","http://resolver.tudelft.nl/uuid:0c42da05-0eb0-48be-9a0d-3b167135eeb7","Thermodynamic investigations of the NaI-CsI, KI-CsI, and NaF-CsI pseudo-binary systems","Scuro, N. L. (University of Ontario Institute of Technology); Fitzpatrick, B. W.N. (University of Ontario Institute of Technology); Geiger, E. (University of Ontario Institute of Technology; Canadian Nuclear Laboratories, ON); Poschmann, M. (University of Ontario Institute of Technology; Canadian Nuclear Laboratories, ON); Dumaire, T. (TU Delft RST/Reactor Physics and Nuclear Materials; European Commission Joint Research Centre); Beneš, O. (European Commission Joint Research Centre); Piro, M. H.A. (University of Ontario Institute of Technology)","","2024","The present study describes the thermodynamic assessment of three pseudo-binary systems relevant to CsI solubility in molten iodide salts: KI-CsI, NaI-CsI, and NaF-CsI. The motivation for this study was to corroborate a single previously reported data set of the NaI-CsI system, resolve inconsistencies reported by two different data-sets of the KI-CsI system, and generate new experimental data on the NaF-CsI system. Equilibrium data for all systems were obtained using Differential Scanning Calorimetry. Thermodynamic treatments of the three pseudo-binary systems were revised using the CALPHAD method with the thermodynamic software FactSage and Thermochimica. Both experimental and computational investigations provide increased confidence in the thermochemical behaviour of CsI in Molten Salt Reactor nuclear systems.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-13","","","RST/Reactor Physics and Nuclear Materials","","",""
"uuid:ce45ce18-6b1b-43ad-8943-8aec896604d5","http://resolver.tudelft.nl/uuid:ce45ce18-6b1b-43ad-8943-8aec896604d5","Author Correction: A global model of hourly space heating and cooling demand at multiple spatial scales (Nature Energy, (2023), 8, 12, (1328-1344), 10.1038/s41560-023-01341-5)","Staffell, Iain (Imperial College London); Pfenninger, Stefan (TU Delft Energie and Industrie); Johnson, Nathan (Imperial College London)","","2024","Correction to: Nature Energyhttps://doi.org/10.1038/s41560-023-01341-5, published online 14 September 2023. In the version of this article initially published, there was a typographical error in the third term of equation (2) in the Methods section, which now reads “S * = 100 + 7T, W * = 4.5 – 0.025T, H * = e 1.1+0.06T, T * = 16”, where e 1.1+0.06T appeared originally as e 1.1+0.6T. This error was in presentation only and does not affect the results or source code. The equation has been amended in the HTML and PDF versions of the article.","","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:85fd0eb1-83ec-4e34-9ac8-be6b32082a52","http://resolver.tudelft.nl/uuid:85fd0eb1-83ec-4e34-9ac8-be6b32082a52","10th International Airborne Wind Energy Conference (AWEC 2024): Book of Abstracts","","Delft University of Technology (organizer); Sánchez-Arriaga, Gonzalo (editor); Thoms, Stefanie (editor); Schmehl, Roland (editor)","2024","","","","conference","Delft University of Technology","978-94-6366-844-6","","","","","","","","","","","",""
"uuid:a73bcf93-1a5d-453d-94ea-24613b096acc","http://resolver.tudelft.nl/uuid:a73bcf93-1a5d-453d-94ea-24613b096acc","Laying the experimental foundation for corrosion inhibitor discovery through machine learning","Özkan, C. (TU Delft Team Arjan Mol); Sahlmann, Lisa (Helmholtz-Zentrum Hereon); Feiler, Christian (Helmholtz-Zentrum Hereon); Zheludkevich, Mikhail (Helmholtz-Zentrum Hereon); Lamaka, Sviatlana (Helmholtz-Zentrum Hereon); Sewlikar, Parth (Vrije Universiteit Brussel); Kooijman, A.M. (TU Delft Team Arjan Mol); Taheri, P. (TU Delft Team Peyman Taheri); Mol, J.M.C. (TU Delft Team Arjan Mol)","","2024","Creating durable, eco-friendly coatings for long-term corrosion protection requires innovative strategies to streamline design and development processes, conserve resources, and decrease maintenance costs. In this pursuit, machine learning emerges as a promising catalyst, despite the challenges presented by the scarcity of high-quality datasets in the field of corrosion inhibition research. To address this obstacle, we have created an extensive electrochemical library of around 80 inhibitor candidates. The electrochemical behaviour of inhibitor-exposed AA2024-T3 substrates was captured using linear polarisation resistance, electrochemical impedance spectroscopy, and potentiodynamic polarisation techniques at different exposure times to obtain the most comprehensive electrochemical picture of the corrosion inhibition over a 24-h period. The experimental results yield target parameters and additional input features that can be combined with computational descriptors to develop quantitative structure–property relationship (QSPR) models augmented by mechanistic input features.","","en","journal article","","","","","","","","","","","Team Arjan Mol","","",""
"uuid:f9d2d24d-7da4-49a0-866b-75e8a16d9f86","http://resolver.tudelft.nl/uuid:f9d2d24d-7da4-49a0-866b-75e8a16d9f86","The Effects of Different Motor Teaching Strategies on Learning a Complex Motor Task","Kunavar, Tjasa (Jozef Stefan Institute; Jožef Stefan International Postgraduate School); Jamšek, Marko (Jozef Stefan Institute); Avila-Mireles, Edwin Johnatan (Jozef Stefan Institute); Rueckert, Elmar (Montan University of Leoben); Peternel, L. (TU Delft Human-Robot Interaction); Babič, Jan (Jozef Stefan Institute; University of Ljubljana)","","2024","During the learning of a new sensorimotor task, individuals are usually provided with instructional stimuli and relevant information about the target task. The inclusion of haptic devices in the study of this kind of learning has greatly helped in the understanding of how an individual can improve or acquire new skills. However, the way in which the information and stimuli are delivered has not been extensively explored. We have designed a challenging task with nonintuitive visuomotor perturbation that allows us to apply and compare different motor strategies to study the teaching process and to avoid the interference of previous knowledge present in the naïve subjects. Three subject groups participated in our experiment, where the learning by repetition without assistance, learning by repetition with assistance, and task Segmentation Learning techniques were performed with a haptic robot. Our results show that all the groups were able to successfully complete the task and that the subjects’ performance during training and evaluation was not affected by modifying the teaching strategy. Nevertheless, our results indicate that the presented task design is useful for the study of sensorimotor teaching and that the presented metrics are suitable for exploring the evolution of the accuracy and precision during learning.","human–robot interaction; motor learning; motor teaching; robot tutoring; skill learning; tracking task; visuomotor perturbation","en","journal article","","","","","","","","","","","Human-Robot Interaction","","",""
"uuid:61a64c77-3162-48db-917b-62a2f0d96092","http://resolver.tudelft.nl/uuid:61a64c77-3162-48db-917b-62a2f0d96092","Validation of a hand hygiene visual feedback system to improve compliance with drying time of alcohol-based hand rub in a neonatal intensive care unit: the Incubator Traffic Light system","van Gils, R.H.J. (Erasmus MC; Rotterdam University of Applied Sciences); Kornelisse, R. F. (Erasmus MC); Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology); Helder, O. K. (Erasmus MC; Rotterdam University of Applied Sciences)","","2024","Background: Compliance with the recommended 30 s drying time of alcohol-based hand rub (ABHR) is often suboptimal. To increase hand hygiene compliance at a neonatal intensive care unit (NICU), we installed an Incubator Traffic Light (ITL) system which shows ‘green light’ to open incubator doors after the recommended drying time. Aim: To measure the impact of this visual feedback system on NICU healthcare professionals' compliance with the recommended ABHR drying time. Methods: Ten traffic light systems were installed on incubators at a NICU, five of which provided visual feedback, and five, serving as a control group, did not provide visual feedback. During a two-month period, the systems measured drying time between the moment of dispensing ABHR and opening the incubator's doors. The drying times of the incubators were compared with and without feedback. Findings: Of the 6422 recorded hand hygiene events, 658 were valid for data analysis. Compliance with correct drying time reached 75% (N = 397/526) for incubators equipped with visual feedback versus 36% (N = 48/132; P < 0.0001) for incubators lacking this feature. Conclusion: The ITL improves compliance with the recommended 30 s ABHR drying time in a NICU setting.","Alcohol-based hand rub; Drying time; Guideline adherence; Hand hygiene; Hand sanitizers; Neonatal intensive care unit; Sensory feedback","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:82fae3a0-badf-4dcc-8862-42adec500cd6","http://resolver.tudelft.nl/uuid:82fae3a0-badf-4dcc-8862-42adec500cd6","Managing public real estate and the trade-off between supporting user activities and sustainable development: case of the Netherlands police","van Staveren, D. (TU Delft Real Estate Management); Arkesteijn, M.H. (TU Delft Real Estate Management); den Heijer, A.C. (TU Delft Real Estate Management)","","2024","Purpose: Corporate real estate management (CREM) is complex due to an increasing number of real estate (RE) added values and the tensions between them. RE managers are faced with trade-offs: to choose a higher performance for one added value at the cost of another. CREM research mainly deals with trade-offs in a hypothetical sense, without looking at the characteristics of the RE portfolio nor the specific context in which trade-offs are made. The purpose of this paper is to further develop the concept of real estate value (REV) optimisation with regard to tensions between decreasing CO2 emissions and supporting user activities. Design/methodology/approach: Mixed method study. REV optimisation between user activities and energy efficiency for police stations in the Netherlands built between 2000 and 2020 is analysed. This is complemented by interviews with an RE manager and senior user of police stations and analysis of policy documents. Findings: xThe characteristics of the police station portfolio indicate no correlation between user activities and energy efficiency for the case studied. This is complemented by interviews, from which it becomes clear that there was in fact little tension between supporting user activities and energy efficiency. The performances of these two different added values were optimised separately. Originality/value: This study combines different scales (building and portfolio level) with different types of data: portfolio analysis, document analysis and interviews. This creates a comprehensive image of whether and how the Netherlands police optimised the two RE values.","Management; Police; Real estate; Trade-off; Value","en","journal article","","","","","","","","","","","Real Estate Management","","",""
"uuid:1f2892fc-a73a-4398-8c29-eecb130694d9","http://resolver.tudelft.nl/uuid:1f2892fc-a73a-4398-8c29-eecb130694d9","Effect of delayed inhibitor supply on AA2024-T3 intermetallic activity: A local in situ analysis with reflected microscopy","Mopon, M. (TU Delft Group Garcia Espallargas; University of the Philippines Diliman); Mol, J.M.C. (TU Delft Team Arjan Mol); Garcia, Santiago J. (TU Delft Group Garcia Espallargas)","","2024","Understanding how late an inhibitor can be released once corrosion initiated without compromising corrosion protection may help in developing more efficient anticorrosion coatings. We explored this idea through time-controlled Ce(NO3)3 availability to AA2024-T3 immersed in 0.05 M NaCl. Ce(NO3)3 was supplied at 0, 30, 60, and 180 s from the start of immersion to get a concentration of 0.001 M. Detailed visualization of surface changes at the intermetallic particle level was obtained using in-situ reflected microscopy. SEM-EDX and confocal laser microscopy confirmed the extent of intermetallic degradation and local inhibitor deposition corresponding to operando changes. When the inhibitor is supplied within 60 s of immersion, the surface changes slowdown earlier and are visually less extensive than in uninhibited systems. Furthermore, our results highlight the potential of reflected microscopy for local corrosion inhibition studies and underscore the importance of understanding the interaction between inhibitor release timing and corrosion protection.","Corrosion inhibition; Difference imaging; Inhibitor deposition kinetics; Metallographic microscopy","en","journal article","","","","","","","","","","","Group Garcia Espallargas","","",""
"uuid:fd417948-5544-4cef-a577-cc4c1c2d08c4","http://resolver.tudelft.nl/uuid:fd417948-5544-4cef-a577-cc4c1c2d08c4","Occupants’ inquiries for energy efficiency retrofitting in the Netherlands","Maghsoudi Nia, E. (TU Delft Environmental & Climate Design; TU Delft Design & Construction Management); Qian, QK (TU Delft Design & Construction Management); Visscher, H.J. (TU Delft Design & Construction Management)","","2024","Highlights
• The aging systems, and the house's condition, are important factors that motivate occupants to consider energy retrofitting.
• Educating occupants on regular monitoring can enhance the durability and performance of energy-efficient technologies.
• Policymakers need to implement region-specific strategies, to promote energy retrofitting initiatives.","","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:97aeb242-8aa7-415b-9c45-84e0023e5eae","http://resolver.tudelft.nl/uuid:97aeb242-8aa7-415b-9c45-84e0023e5eae","Optimal chartering decisions for vessel fleet to support offshore wind farm maintenance operations","Li, M. (TU Delft Transport Engineering and Logistics; University of Strathclyde); Bijvoet, Bas (Student TU Delft); Wu, Kangjie (Student TU Delft); Jiang, X. (TU Delft Transport Engineering and Logistics); Negenborn, R.R. (TU Delft Transport Engineering and Logistics)","","2024","Offshore wind energy is expected to be the most significant source of future electricity supply in Europe. Offshore wind farms are located far from the shores, requiring a fleet of various types of vessels to access sites when maintaining offshore wind turbines. The employment of the vessels is costly, accounting for the majority of the total O&M costs for offshore wind energy. Therefore, configuring the size and mix of the vessel fleet to support maintenance operations in a cost-effective manner is an issue of importance to enhance economics of offshore wind sector. In this paper, a discrete event simulation based model is proposed to present how a mixed vessel fleet with the specific configuration, including crew transfer vessels, field support vessels, and heavy lift vessels, performs maintenance for an offshore wind farm. The economic performance of the vessel fleet under a predetermined condition-based opportunistic maintenance strategy is investigated by using the model. A metaheuristic algorithm, simulated annealing, is employed to find the optimal fleet size and mix to make leasing decisions with the minimum costs. The performance of the developed approaches is evaluated by using a generic offshore wind farm in the North Sea. The sensitivity analysis is performed to investigate the most influential O&M factors.","Condition-based opportunistic maintenance; Offshore wind energy; Operation and maintenance; Vessel fleet","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:eefd5649-cd09-4702-b801-f247b0300377","http://resolver.tudelft.nl/uuid:eefd5649-cd09-4702-b801-f247b0300377","Highly-sensitive wafer-scale transfer-free graphene MEMS condenser microphones","Pezone, R. (TU Delft Electronic Components, Technology and Materials); Anzinger, Sebastian (Infineon Technologies AG); Baglioni, G. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Wasisto, Hutomo Suryo (Infineon Technologies AG); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Steeneken, P.G. (TU Delft Dynamics of Micro and Nano Systems; TU Delft QN/Steeneken Lab; Kavli institute of nanoscience Delft); Vollebregt, S. (TU Delft Electronic Components, Technology and Materials)","","2024","Since the performance of micro-electro-mechanical system (MEMS)-based microphones is approaching fundamental physical, design, and material limits, it has become challenging to improve them. Several works have demonstrated graphene’s suitability as a microphone diaphragm. The potential for achieving smaller, more sensitive, and scalable on-chip MEMS microphones is yet to be determined. To address large graphene sizes, graphene-polymer heterostructures have been proposed, but they compromise performance due to added polymer mass and stiffness. This work demonstrates the first wafer-scale integrated MEMS condenser microphones with diameters of 2R = 220–320 μm, thickness of 7 nm multi-layer graphene, that is suspended over a back-plate with a residual gap of 5 μm. The microphones are manufactured with MEMS compatible wafer-scale technologies without any transfer steps or polymer layers that are more prone to contaminate and wrinkle the graphene. Different designs, all electrically integrated are fabricated and characterized allowing us to study the effects of the introduction of a back-plate for capacitive read-out. The devices show high mechanical compliances Cm = 0.081–1.07 μmPa−1 (10–100 × higher than the silicon reported in the state-of-the-art diaphragms) and pull-in voltages in the range of 2–9.5 V. In addition, to validate the proof of concept, we have electrically characterized the graphene microphone when subjected to sound actuation. An estimated sensitivity of S1kHz = 24.3–321 mV Pa−1 for a Vbias = 1.5 V was determined, which is 1.9–25.5 × higher than of state-of-the-art microphone devices while having a ~9 × smaller area. (Figure presented.).","","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:cb5f32ea-6f50-4764-b343-c150aa9a487d","http://resolver.tudelft.nl/uuid:cb5f32ea-6f50-4764-b343-c150aa9a487d","A History Matching Study for the FluidFlower Benchmark Project","Tian, X. (TU Delft Reservoir Engineering; Chinese Academy of Sciences); Wapperom, M.B. (TU Delft Reservoir Engineering); Gunning, James (CSIRO Energy); Jackson, Samuel (CSIRO Energy); Wilkins, Andy (CSIRO Mineral Resources); Green, Chris (CSIRO Energy); Ennis-King, Jonathan (CSIRO Energy); Voskov, D.V. (TU Delft Reservoir Engineering; Stanford University)","","2024","In this study, we conduct a comprehensive history matching study for the FluidFlower benchmark model. This benchmark was prepared and organized by the University of Bergen, the University of Stuttgart, and Massachusetts Institute of Technology, for promoting understanding of the complex physics of geological carbon storage (GCS) through in-house experiments and numerical simulations. This paper synthesizes the experiences of history matching the benchmark data encountered by the Delft-DARTS and CSIRO participants. History matching is first performed based on a low-dimensional-zonated structured model using a simple Poisson-like solver. The permeability of six facies and two faults is inferred in this stage to match the digitized concentration data. The history matching is then further enhanced to richer spatial and physical models to capture the spatial variation of permeability and buoyancy effects, using an unstructured grid. Efficient adjoint methods are used to evaluate the gradient used in the optimization of data misfits or equivalent Bayesian log-likelihoods. With efficient optimization methods available for both maximum a posteriori model inference and Randomized Maximum Likelihood methods for model uncertainty, we perform history matching using both binary and continuous concentration observations. The results show that the tracer plumes in the enriched model match the experimental plumes more accurately compared with the results from the parsimonious-zonated model. The history matching results based on the concentration observations provide more similar plume shapes compared with the case based on the binary observations. The permeability difference between the model before and after history matching reveals that the tracer plume zone and the high permeable zone are the regions of high sensitivity in terms of data misfit between the model response and observations. Surprisingly, CO 2 concentration plume forecasts based on these history-matched models were not especially sensitive to the improvements observed in the enhanced model.","Adjoint gradients; CCS; DARTS; FluidFlower; History matching","en","journal article","","","","","","DOI 10.1007/s11242-024-02065-0 correction: In the original published article, one of the affliation details for corresponding author ""Denis Voskov"" were incorrectly given as ""Department of Energy Resources Engineering, Stanford University, CA, USA"" but should have been ""Department of Energy Science and Engineering, Stanford University, CA, USA. It is updated in the correction","","","","","Reservoir Engineering","","",""
"uuid:7283ac18-a8fa-4a90-966b-30999a3ee918","http://resolver.tudelft.nl/uuid:7283ac18-a8fa-4a90-966b-30999a3ee918","Risk assessment methods for process safety, process security and resilience in the chemical process industry: A thorough literature review","Bin Ab Rahim, M.S. (TU Delft Safety and Security Science; Ministry of Human Resources); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven); Yang, M. (TU Delft Safety and Security Science; Universiti Teknologi Malaysia; University of Tasmania); Bajpai, Shailendra (Dr B.R. Ambedkar National Institute of Technology)","","2024","This paper presents a systematic literature review of risk assessment methods in the chemical process industry (CPI), focusing on process safety, process security, and resilience. We analyzed peer-reviewed articles from 2000 to 2022 using the PRISMA methodology and identified twelve predominant methods. Our findings reveal a shift towards dynamic, systemic-based assessments like the Functional Resonance Analysis Method (FRAM) and System-Theoretic Accident Model and Processes (STAMP). These methods are particularly effective at capturing the complexities of sociotechnical systems in the CPI. However, a significant observation from our review is the limited emphasis on the resilience paradigm within many existing methods when addressing both process safety and process security risks, which is crucial for preventing and recovering from disruptions. Given the evolving challenges in system safety and security threats, there is an urgent need for holistic methods that integrate process safety, process security, and resilience. Our review highlights the opportunity for further research to better prepare the industry for future challenges, ensuring safer, more secure, reliable, and resilient operations.","Chemical process industry; Process safety; Process security; Resilience; Risk assessment; Sociotechnical systems","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:f732eb66-a151-4634-b1c6-78672b5fdbec","http://resolver.tudelft.nl/uuid:f732eb66-a151-4634-b1c6-78672b5fdbec","A risk-based fuzzy arithmetic model to determine safety integrity levels considering individual and societal risks","Cheraghi, Morteza (Toronto Metropolitan University); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Katholieke Universiteit Leuven; Universiteit Antwerpen); Eslami Baladeh, Aliakbar (Toronto Metropolitan University); Khakzad, Nima (Toronto Metropolitan University); Taghipour, Sharareh (Toronto Metropolitan University)","","2024","Risk-based techniques such as risk graph and Layer of Protection Analysis (LOPA) are used to determine the Safety Integrity Level (SIL) of safety instrumented functions to ensure that risk is reduced to a tolerable level. However, these techniques have some drawbacks. For instance, they need absolute and precise numbers to evaluate SIL parameters, which are rarely available or are highly uncertain. In addition, they are incapable of considering individual and societal risks simultaneously. Moreover, risk tolerance criteria are likely to be used incorrectly in the LOPA technique, and risk graph is difficult to calibrate. In the current paper, a novel comprehensive fuzzy arithmetic model has been developed to determine the required SILs in process industries. The fuzzy required Risk Reduction Factor (RRF) is calculated for both individual and societal risks. Fuzzy numbers are developed from crisp intervals, based on the expected interval of the fuzzy numbers. Expert fuzzy-scaled elicitation has been applied to obtain the SIL parameters. In the proposed model, the overall risk tolerance criterion and apportionment factor are defined as SIL parameters for both individual and societal risks to ensure that the applied risk criteria are compliant with the requirements of the system. In addition, an approach is introduced for determining the required SIL based on the fuzzy required RRF. The proposed methodology was demonstrated to alleviate the limitations, and thus, can be considered as a more precise alternative to the conventional methods.","fuzzy; individual risk; safety instrumented system; safety integrity level; societal risk","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-13","","","Safety and Security Science","","",""
"uuid:96fc37eb-854e-4427-870a-86ef71575f64","http://resolver.tudelft.nl/uuid:96fc37eb-854e-4427-870a-86ef71575f64","Structural biology of microbial gas vesicles: historical milestones and current knowledge","Huber, S. (TU Delft BN/Arjen Jakobi Lab); Jakobi, A. (TU Delft BN/Arjen Jakobi Lab)","","2024","Gas vesicles mediate buoyancy-based motility in aquatic bacteria and archaea and are the only protein-based structures known to enclose a gas-filled volume. Their unique physicochemical properties and ingenious architecture rank them among the most intriguing macromolecular assemblies characterised to date. This review covers the 60-year journey in quest for a high-resolution structural model of gas vesicles, first highlighting significant strides made in establishing the detailed ultrastructure of gas vesicles through transmission electron microscopy, X-ray fibre diffraction, atomic force microscopy, and NMR spectroscopy. We then survey the recent progress in cryogenic electron microscopy studies of gas vesicles, which eventually led to a comprehensive atomic model of the mature assembly. Synthesising insight from these structures, we examine possible mechanisms of gas vesicle biogenesis and growth, presenting a testable model to guide future experimental work. We conclude by discussing future directions in the structural biology of gas vesicles, particularly considering advancements in AI-driven structure prediction.","","en","review","","","","","","","","","","","BN/Arjen Jakobi Lab","","",""
"uuid:5152d5f1-2d65-43df-9b95-d17426342722","http://resolver.tudelft.nl/uuid:5152d5f1-2d65-43df-9b95-d17426342722","Challenges in advancing our understanding of atomic-like quantum systems: Theory and experiment","Gali, Adam (Wigner Research Centre for Physics; Budapest University of Technology and Economics); Schleife, André (University of Illinois at Urbana-Champaign); Heinrich, Andreas J. (Institute for Basic Science (IBS); Ewha Womans University); Laucht, Arne (University of New South Wales); Schuler, Bruno (Swiss Federal Laboratories for Materials Science and Technology (Empa); Wigner Research Centre for Physics); Chakraborty, Chitraleema (University of Delaware; Wigner Research Centre for Physics); Anderson, Christopher P. (Wigner Research Centre for Physics); Déprez, C.C. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; Wigner Research Centre for Physics); McCallum, Jeffrey (Wigner Research Centre for Physics)","","2024","Abstract: Quantum information processing and quantum sensing is a central topic for researchers who are part of the Materials Research Society and the Quantum Staging Group is providing leadership and guidance in this context. We convened a workshop before the 2022 MRS Spring Meeting and covered four topics to explore challenges that need to be addressed to further promote and accelerate the development of materials with applications in quantum technologies. This article captures the discussions at this workshop and refers to the pertinent literature. Graphical abstract: (Figure presented.).","Defect qubits; Donor and acceptors; Quantum dots; Quantum emitters; Quantum materials","en","review","","","","","","","","","","","QCD/Veldhorst Lab","","",""
"uuid:feaeb0ba-a52b-4bb2-b564-5005b38884ff","http://resolver.tudelft.nl/uuid:feaeb0ba-a52b-4bb2-b564-5005b38884ff","Why Shot Noise Does Not Generally Detect Pairing in Mesoscopic Superconducting Tunnel Junctions","Niu, Jiasen (Universiteit Leiden); Bastiaans, K.M. (TU Delft QN/Otte Lab; Kavli institute of nanoscience Delft); Ge, Jian Feng (Universiteit Leiden); Tomar, Ruchi (Tata Institute of Fundamental Research); Jesudasan, John (Tata Institute of Fundamental Research); Raychaudhuri, Pratap (Tata Institute of Fundamental Research); Karrer, Max (Eberhard Karls Universität Tübingen); Driessen, Eduard F.C. (Université Grenoble Alpes); Blanter, Y.M. (TU Delft QN/Blanter Group; Kavli institute of nanoscience Delft)","","2024","The shot noise in tunneling experiments reflects the Poissonian nature of the tunneling process. The shot-noise power is proportional to both the magnitude of the current and the effective charge of the carrier. Shot-noise spectroscopy thus enables us, in principle, to determine the effective charge q of the charge carriers of that tunnel. This can be used to detect electron pairing in superconductors: In the normal state, the noise corresponds to single electron tunneling (q=1e), while in the paired state, the noise corresponds to q=2e. Here, we use a newly developed amplifier to reveal that in typical mesoscopic superconducting junctions, the shot noise does not reflect the signatures of pairing and instead stays at a level corresponding to q=1e. We show that transparency can control the shot noise, and this q=1e is due to the large number of tunneling channels with each having very low transparency. Our results indicate that in typical mesoscopic superconducting junctions, one should expect q=1e noise and lead to design guidelines for junctions that allow the detection of electron pairing.","","en","journal article","","","","","","","","","","","QN/Otte Lab","","",""
"uuid:dadafd2e-823d-453b-8542-a50af6923346","http://resolver.tudelft.nl/uuid:dadafd2e-823d-453b-8542-a50af6923346","Mimosa: Modular Self-folding Hinges Kit for Creating Shape-changing Objects","Liu, Q. (TU Delft Emerging Materials); Ghodrat, S. (TU Delft Emerging Materials); Jansen, K.M.B. (TU Delft Emerging Materials)","","2024","We developed a shape-changing constructive kit, named Mimosa1. A key component of the toolkit is the modular hinges, each of which is equipped with two antagonistic shape memory alloy (SMA) wires. One wire deforms the hinge to approach its predetermined angle at high temperature, and another wire drives the hinge back when it cools down. Hinge leaves are available in different materials including acrylic, cardboard and textile, which increases the versatility of the toolkit. Every hinge weighs 2.1-5.4 g, and generates up to 5.7 N actuation force. A Bluetooth control module was developed, enabling remote control of the shape-changing objects. Mimosa aims to inspire designers to explore and create interactive shape-morphing objects with SMAs. A few examples are given such as a gripper, a rolling robot, a butterfly, an airplane and a self-closing pocket. A workshop study with 6 participants showed that Mimosa indeed motivated and inspired the participants to create new ideas.","Crafting; Shape Memory Alloy; Shape-Changing Interfaces; Smart Hinge; Tangible User Interfaces; Toolkit","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Emerging Materials","","",""
"uuid:db27eb09-d289-4126-b88f-7c510108ae92","http://resolver.tudelft.nl/uuid:db27eb09-d289-4126-b88f-7c510108ae92","Social acceptance of district heating: evidence from the Netherlands","Onencan, A. M. (Erasmus Universiteit Rotterdam); Ou, J. (Universiteit Utrecht); de Koning, J.I.J.C. (TU Delft Design for Sustainability)","","2024","The Netherlands Climate Change Agreement aims to reduce CO2 emissions and seismic events by halting natural gas usage by 2050. This will require widespread societal acceptance by 90% of households. The study investigates the social acceptance of a district heating network (DHN) among social housing tenants in Haarlem, Netherlands. The findings of a survey administered to ninety-five tenants revealed a substantial level of support for the DHN project. A significant portion of respondents, 75%, expressed their approval for the DHN, surpassing the legally required threshold of 70% for implementing building retrofits. Findings imply that although the participants possess an adequate comprehension of the rationale for energy transition, their familiarity with the precise particulars and practical information pertaining to the proposed transition to DHN is inadequate. The level of trust in housing corporations, energy providers, and the municipality is uniformly low, indicating a lack of institutional trust. Generally, the interpersonal trust among tenants tends to be lower than their trust in the broader public, which in turn restricts their capacity for self-organization and exercising influence over energy institutions. Although DHNs are typically regarded as environmentally friendly and secure, there are several challenges that need to be addressed, including the uncertainty about who will cover the costs of transitioning and the doubts surrounding DHN feasibility (warmth and reliability). We suggest implementing interventions to improve tenants' comprehension of the DHN project's particulars (capability), provide practical information regarding costs and feasibility (motivation), and foster trust at both interpersonal and institutional levels (opportunity).","COM-B model; Energy transition; Institutional change; Social acceptance; Sustainable behaviour; Systemic change","en","journal article","","","","","","","","","","","Design for Sustainability","","",""
"uuid:c7b3ba18-62ce-43d2-ae95-ae03f72c349e","http://resolver.tudelft.nl/uuid:c7b3ba18-62ce-43d2-ae95-ae03f72c349e","Assessing the Impact of Metrics on the Choice of Prognostic Methodologies","Bieber, M.T. (TU Delft Air Transport & Operations); Verhagen, W.J.C. (Royal Melbourne Institute of Technology University); Santos, Bruno F. (TU Delft Air Transport & Operations)","","2024","Over the past years, advanced prognostic models and approaches have been developed. Most existing approaches are tailored to one specific system and cannot adaptively be used on different systems. This can lead to years of research and expertise being put into implementing prognostic models without the capacity to predict system failures, either because of a lack of data or data quality or because failure behavior cannot be captured by data-driven models. In addition, prognostic models are often evaluated using metrics only related to the correctness of predictions, preventing meaningful evaluation of operational performance. This paper makes use of a framework that can automatically choose prognostic settings based on specific system data. It simultaneously optimizes the choice of methodologies using metrics that capture multiple aspects of prediction quality. We apply this framework to both a simulated data set and a real aircraft data set to characterize the impact of metrics on the choice of prognostic methodologies. The results show that the choice of optimization metric greatly impacts the output of the generic prognostic framework and the overall performance. In addition, a definition for data suitability is provided and assessed on the aircraft system data sets.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-09","","","Air Transport & Operations","","",""
"uuid:7664ea4f-f8c6-4bd3-9087-161e2eb41aa3","http://resolver.tudelft.nl/uuid:7664ea4f-f8c6-4bd3-9087-161e2eb41aa3","A 1-dimensional-two-layer transient drift-flux model for hydraulic transport pipelines: modelling and experiments of bed layer erosion and density wave amplification","de Hoog, E. (TU Delft Offshore and Dredging Engineering; Royal IHC); van der Voort, Tjalie (Royal IHC); Talmon, A.M. (TU Delft Offshore and Dredging Engineering; Deltares); van Rhee, C. (TU Delft Offshore and Dredging Engineering)","","2024","Hydraulic transport pipelines in the dredging, mining and deep sea mining are designed using steady-state methods. However, these methods cannot predict density wave formation. Density waves form a risk for pipeline blockages, therefore there is a need to understand and preferably be able to model the process. The density waves studied in this research are caused by a stationary sediment deposit in the pipeline. This article explores the development of a new transient design model, based on 1-dimensional-two-layer Driftflux CFD. The two layers model the exchange of sediment between the turbulent suspension, and a stationary bed layer, and can therefore model density wave amplification. An empirical erosion-sedimentation closure relationship is applied to model the sediment exchange between the two layers, and is calibrated using experiments. The final model is also validated against a second experiment, specifically for density wave amplification. The experiments and the model show good agreement on the erosion of a stationary bed layer and the growth rate of a density wave and the amplitude of the density wave.","Deep sea mining; Dredging; Driftflux; Flow assurance; Hydraulic transport; Transients","en","journal article","","","","","","","","","","","Offshore and Dredging Engineering","","",""
"uuid:c4997b49-e52b-4d5c-a7be-c3a26d941b72","http://resolver.tudelft.nl/uuid:c4997b49-e52b-4d5c-a7be-c3a26d941b72","Analysis of the impact of traffic density on training of reinforcement learning based conflict resolution methods for drones","Groot, D.J. (TU Delft Control & Simulation); Ellerbroek, Joost (TU Delft Control & Simulation); Hoekstra, J.M. (TU Delft Control & Simulation)","","2024","Conventional Air Traffic Control is still predominantly being done by human Air Traffic Controllers, however, as the traffic density increases, the workload of the controllers increases as well. Especially for the area of unmanned aviation, driven by the rise in drones, having human controllers might become unfeasible. One of the methods that is currently being investigated for replacing the conflict resolution task of Air Traffic Control is Reinforcement Learning. As violation of the required separation margins, also called an intrusion, is an event of relatively low frequency, using Reinforcement Learning for this task comes with difficulties that can potentially be attributed to data imbalance. This paper artificially increased the traffic density during the training phase of the Reinforcement Learning method to investigate what the importance is of a balanced data set on the performance of the Reinforcement Learning method. It was found that as the traffic density increased, the Reinforcement Learning methods started to outperform the analytical methods. Beyond this it was found that methods trained at higher traffic densities, but tested at lower traffic densities, outperformed the methods trained at that specific density. This indicates that it might be better to always ensure that the training scenarios are more complex than anticipated during the execution phase, even if that results in unrealistic scenarios.","BlueSky simulator; Conflict resolution; Deep reinforcement learning; High-traffic density; Simulation; Soft actor critic; Unmanned traffic management","en","journal article","","","","","","","","","","","Control & Simulation","","",""
"uuid:98d99bc8-8a4b-4299-a103-0f455bd47c66","http://resolver.tudelft.nl/uuid:98d99bc8-8a4b-4299-a103-0f455bd47c66","Pulsed Operation of a Weakly-Dispersive, Leaky-Wave Antenna: A Causal Numerical Study","Gu, Junhong (Student TU Delft); Stumpf, Martin (Brno University of Technology; Luleå University of Technology); Neto, A. (TU Delft Tera-Hertz Sensing); Lager, I.E. (TU Delft Electrical Engineering Education)","","2024","A strictly causal numerical study of the pulsed operation of a weakly dispersive, leaky wave (LW) antenna is presented. The intricacies at the forefront of the electromagnetic (EM) field radiated from a gap-fed slot in a perfectly electrically conducting (PEC) sheet are evidenced for the first time. The radical effect of a free-space gap separating the PEC sheet from the dielectric half-space into which the slot radiates is demonstrated, thus providing time-domain (TD) arguments for the effectiveness of this essential element of leaky-lens antennas (LLAs). The response of the gapped structure to an excitation consisting of pulse trains is evaluated. The discussed results pave the way toward building a genuine TD counterpart of the LW radiation from gap-fed slots. Furthermore, they are conditional to understanding the transients occurring in between intervals when a steady-state, time-harmonic (TH) operation can be assumed, an extremely relevant ingredient to implementing highly complex modulations in carrier-based, wireless transfer.","Leaky wave antennas; numerical analysis; time-domain analysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-31","","","Tera-Hertz Sensing","","",""
"uuid:b8aaf6d0-516d-4480-aafc-84e171ed89c7","http://resolver.tudelft.nl/uuid:b8aaf6d0-516d-4480-aafc-84e171ed89c7","Meaningful human control and variable autonomy in human-robot teams for firefighting","Verhagen, R.S. (TU Delft Interactive Intelligence); Neerincx, M.A. (TU Delft Interactive Intelligence; TNO); Tielman, M.L. (TU Delft Interactive Intelligence)","","2024","Introduction: Humans and robots are increasingly collaborating on complex tasks such as firefighting. As robots are becoming more autonomous, collaboration in human-robot teams should be combined with meaningful human control. Variable autonomy approaches can ensure meaningful human control over robots by satisfying accountability, responsibility, and transparency. To verify whether variable autonomy approaches truly ensure meaningful human control, the concept should be operationalized to allow its measurement. So far, designers of variable autonomy approaches lack metrics to systematically address meaningful human control.
Methods: Therefore, this qualitative focus group (n = 5 experts) explored quantitative operationalizations of meaningful human control during dynamic task allocation using variable autonomy in human-robot teams for firefighting. This variable autonomy approach requires dynamic allocation of moral decisions to humans and non-moral decisions to robots, using robot identification of moral sensitivity. We analyzed the data of the focus group using reflexive thematic analysis.
Results: Results highlight the usefulness of quantifying the traceability requirement of meaningful human control, and how situation awareness and performance can be used to objectively measure aspects of the traceability requirement. Moreover, results emphasize that team and robot outcomes can be used to verify meaningful human control but that identifying reasons underlying these outcomes determines the level of meaningful human control.
Discussion: Based on our results, we propose an evaluation method that can verify if dynamic task allocation using variable autonomy in human-robot teams for firefighting ensures meaningful human control over the robot. This method involves subjectively and objectively quantifying traceability using human responses during and after simulations of the collaboration. In addition, the method involves semi-structured interviews after the simulation to identify reasons underlying outcomes and suggestions to improve the variable autonomy approach.","","en","journal article","","","","","","","","","","","Interactive Intelligence","","",""
"uuid:d3295532-eeaf-4c79-b5b6-70011f4253a3","http://resolver.tudelft.nl/uuid:d3295532-eeaf-4c79-b5b6-70011f4253a3","In vitro co-culture models for the assessment of orthopedic antibacterial biomaterials","Eijkel, B.I.M. (TU Delft Biomaterials & Tissue Biomechanics); Apachitei, I. (TU Delft Biomaterials & Tissue Biomechanics); Fratila-Apachitei, E.L. (TU Delft Biomaterials & Tissue Biomechanics); Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics)","","2024","The antibacterial biofunctionality of bone implants is essential for the prevention and treatment of implant-associated infections (IAI). In vitro co-culture models are utilized to assess this and study bacteria-host cell interactions at the implant interface, aiding our understanding of biomaterial and the immune response against IAI without impeding the peri-implant bone tissue regeneration. This paper reviews existing co-culture models together with their characteristics, results, and clinical relevance. A total of 36 studies were found involving in vitro co-culture models between bacteria and osteogenic or immune cells at the interface with orthopedic antibacterial biomaterials. Most studies (∼67%) involved co-culture models of osteogenic cells and bacteria (osteo-bac), while 33% were co-culture models of immune cells and bacterial cells (im-bac). All models involve direct co-culture of two different cell types. The cell seeding sequence (simultaneous, bacteria-first, and cell-first) was used to mimic clinically relevant conditions and showed the greatest effect on the outcome for both types of co-culture models. The im-bac models are considered more relevant for early peri-implant infections, whereas the osteo-bac models suit late infections. The limitations of the current models and future directions to develop more relevant co-culture models to address specific research questions are also discussed.","implant-associated infections; antibacterial biomaterials; in vitro co-culture models; osteogenic cells; immune cells","en","review","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:eb3873be-47b8-45c9-b818-3121e9a73767","http://resolver.tudelft.nl/uuid:eb3873be-47b8-45c9-b818-3121e9a73767","Predicting Detection of Changes in Controlled Element Dynamics by Human Controllers Internal Model","Eppenga, Thomas (TU Delft Aerospace Engineering)","Mulder, Max (mentor); van Paassen, M.M. (mentor); Pool, D.M. (mentor); Delft University of Technology (degree granting institution)","2024","","","en","master thesis","","","","","","","","2026-03-13","","","","Aerospace Engineering","",""
"uuid:1349f6ae-1f9e-49ca-8850-4c50a0ba96d7","http://resolver.tudelft.nl/uuid:1349f6ae-1f9e-49ca-8850-4c50a0ba96d7","Exceptional mechanical performance by spatial printing with continuous fiber: Curved slicing, toolpath generation and physical verification","Fang, G. (TU Delft Emerging Materials; The University of Manchester); Zhang, Tianyu (The University of Manchester); Huang, Yuming (The University of Manchester); Zhang, Zhizhou (The University of Manchester); Masania, K. (TU Delft Group Masania); Wang, C.C. (TU Delft Emerging Materials; The University of Manchester)","","2024","This work explores a spatial printing method to fabricate continuous fiber-reinforced thermoplastic composites (CFRTPCs), which can achieve exceptional mechanical performance. For models giving complex 3D stress distribution under loads, typical planar-layer based fiber placement usually fails to provide sufficient reinforcement due to their orientations being constrained to planes. The effectiveness of fiber reinforcement could be maximized by using multi-axis additive manufacturing (MAAM) to better control the orientation of continuous fibers in 3D-printed composites. Here, we propose a computational approach to generate 3D toolpaths that satisfy two major reinforcement objectives: (1) following the maximal stress directions in critical regions and (2) connecting multiple load-bearing regions by continuous fibers. Principal stress lines are first extracted in an input solid model to identify critical regions. Curved layers aligned with maximal stresses in these critical regions are generated by computing an optimized scalar field and extracting its iso-surfaces. Then, topological analysis and operations are applied to each curved layer to generate a computational domain that preserves fiber continuity between load-bearing regions. Lastly, continuous fiber toolpaths aligned with maximal stresses are generated on each surface layer by computing an optimized scalar field and extracting its iso-curves. A hardware system with dual robotic arms is employed to conduct the physical MAAM tasks depositing polymer or fiber reinforced polymer composite materials by applying a force normal to the extrusion plane to aid consolidation. When comparing to planar-layer based printing results in tension, up to 644% failure load and 240% stiffness are observed on shapes fabricated by our spatial printing method. We demonstrate the versatility of our approach through various complex load cases which demonstrate their successful implementation of continuous fiber printing in 3D.","Continuous fiber reinforced thermoplastic composites; Multi-axis additive manufacturing; Toolpath generation","en","journal article","","","","","","","","","","","Emerging Materials","","",""
"uuid:c45d72e9-aab1-4ad4-b15a-52101b6cc695","http://resolver.tudelft.nl/uuid:c45d72e9-aab1-4ad4-b15a-52101b6cc695","Photoluminescence of combinatorically sputtered Al2O3–Y2O3 thin films with a Cr3+ and Nd3+ co-doping concentration gradient","Derksen, M. (TU Delft RST/Luminescence Materials); Bizinoto Ferreira Bosco, G. (Fotonic); Muller, Timo (Student TU Delft); van der Kolk, E. (TU Delft RST/Luminescence Materials)","","2024","The characterization of a wide range of luminescent thin films can be a long and tedious endeavor. With reactive combinatorial sputtering of multiple metal targets, it possible to fabricate thin films with a gradient in composition simply by not rotating the substrate. In this work, combinatorically sputtered thin films of Cr3+ and Nd3+ doped in the Al2O3–Y2O3 system (YAlO) are studied for thin film based luminescent solar concentrators (TFLSCs) application. Contrary to mm's thick plate type LSC's, TFLSCs of just several 100 nm thick require much higher Cr3+ concentration to achieve 40% absorption which can enable several 10's of W/m2 LSC power efficiencies. Our transmission measurements on a Cr2O3 film with a thickness gradient result in an absorption cross section at 460 nm of 1.3 ± 0.7 × 10−19 cm2 showing that the TFLSC absorption requirement can be fulfilled provided that the Cr3+ concentration is in the order of 1022 ions/cm3. The Y:Al ratio of the YAlO host in our films ranged between 0.5 and 3.5, thereby including the monoclinic (Y4Al2O9), perovskite (YAlO3) and garnet (Y3Al5O12) stoichiometry's on a single film. Position dependent XRD, EDX, excitation, emission and lifetime measurements of Cr3+ and Nd3+ show that the unique gradient film sputtering method is able to characterize thin films as a function of host composition and doping concentration. Energy transfer between Cr3+ and Nd3+ in co-doped YAlO films is concluded from Cr3+ excitation bands observed while monitoring Nd3+ emission and from the matching of the rise-time of Nd3+ 1340 nm emission (4F3/2 -> 4I11/2) and the decay time of Cr3+ 840 nm emission (4T2 -> 4A2). Nd3+ lifetime systematically decreases from 0.24 to 0.05 ms with increasing Cr3+ concentration in Y3Al5-xCrxO12:Nd (0.05 < x < 2). The constraints of heavily doped Cr3+ thin films for enabling adequate absorption and energy transfer to Nd3+ in TFLSC applications are the subjects of the discussion.","Al2O3–Y2O3; Chromium; Energy transfer; Luminescent solar concentrator; Neodymium; Reactive magnetron sputtering; Thin films; YAG, YAP, YAM","en","journal article","","","","","","","","","","","RST/Luminescence Materials","","",""
"uuid:c0b6b99a-971f-4dfb-b13c-238e327ae09b","http://resolver.tudelft.nl/uuid:c0b6b99a-971f-4dfb-b13c-238e327ae09b","An alternative process-based approach to predicting the response of water-saturated porous media to harmonic hydrodynamic loads","van Damme, M. (TU Delft Numerical Analysis); den Ouden-van der Horst, D. (TU Delft Numerical Analysis)","","2024","Methods have been developed to predict how hydrodynamic loads acting on nearly saturated porous media are transmitted to the subsoil. In line with the effective stress principle of Terzaghi, these methods apply the boundary conditions that the effective stresses at the surface of a porous medium are zero, and that the pore water pressures carry the full load. Here, a new approach is presented which is based on defining a stress and a stress gradient as boundary conditions. The stress gradient follows from the momentum balance equation, thereby assuring that the solution abides by d'Alembert's principle of minimization of virtual work. The corresponding solution is in full accordance with the volume and momentum balance equations of the linear elastic soil matrix and the volume and momentum balance equations of the pore water across the computational domain. The new method is thereby able to correctly reproduce measurements of pore pressure changes due to hydrodynamic loads under the assumption of a porous medium consisting of incompressible particles and pore water which could either be compressible or incompressible. The advantage of the proposed method is that it requires one less boundary condition at the surface of the porous medium. The method is therefore able to predict the magnitude of the effective stresses on a soil surface. Due to the ability to retain the assumption of incompressible water, the method has also become independent on a calibration parameter. The results of the method induce questions with respect to the validity of Terzaghi's principle of effective stress at the boundary when porous media are subjected to hydrodynamic loads.","elastic; harmonic; liquefaction; momentum; porous; pulling force; saturated; waves","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-01","","","Numerical Analysis","","",""
"uuid:2a089659-6695-49b2-894e-3647f95f79fa","http://resolver.tudelft.nl/uuid:2a089659-6695-49b2-894e-3647f95f79fa","Particle filter-based fatigue damage prognosis by fusing multiple degradation models","Li, Tianzhi (Politecnico di Milano); Chen, Jian (Nanjing University of Aeronautics and Astronautics); Yuan, Shenfang (Nanjing University of Aeronautics and Astronautics); Zarouchas, D. (TU Delft Group Zarouchas); Sbarufatti, Claudio (Politecnico di Milano); Cadini, Francesco (Politecnico di Milano)","","2024","Fatigue damage prognosis always requires a degradation model describing the damage evolution with time; thus, the prognostic performance highly depends on the selection of such a model. The best model should probably be case specific, calling for the fusion of multiple degradation models for a robust prognosis. In this context, this paper proposes a scheme of online fusing multiple models in a particle filter (PF)-based damage prognosis framework. First, each prognostic model has its process equation built through a physics-based or data-driven degradation model and has its measurement equation linking the damage state and the measurement. Second, each model is independently processed through one PF to provide one group of particles. Then, the particles from all models are adopted for remaining useful life prediction. Finally, the particles from each PF are fused with those from all the other PFs to improve their particle diversity, and consequently, to provide better estimation and prognostic performance. The feasibility and robustness of the proposed method are validated by an experimental study, where an aluminum lug structure subject to fatigue crack growth is monitored by a guided wave measurement system.","damage prognosis; degradation model; fusion; Lamb waves; particle diversity; particle filter; Structural health monitoring","en","journal article","","","","","","","","","","","Group Zarouchas","","",""
"uuid:c15129c1-4e9e-4a0a-9932-ea913082d16d","http://resolver.tudelft.nl/uuid:c15129c1-4e9e-4a0a-9932-ea913082d16d","CRISPR-controlled proteases","van Beljouw, S.P.B. (TU Delft BN/Stan Brouns Lab; Kavli institute of nanoscience Delft); Brouns, S.J.J. (TU Delft BN/Stan Brouns Lab; Kavli institute of nanoscience Delft)","","2024","With the discovery of CRISPR-controlled proteases, CRISPR–Cas has moved beyond mere nucleic acid targeting into the territory of targeted protein cleavage. Here, we review the understanding of Craspase, the best-studied member of the growing CRISPR RNA-guided protease family. We recollect the original bioinformatic prediction and early experimental characterizations; evaluate some of the mechanistic structural intricacies and emerging biotechnology; discuss open questions and unexplained mysteries; and indicate future directions for the rapidly moving field of the CRISPR proteases.","","en","review","","","","","","","","2024-08-09","","","BN/Stan Brouns Lab","","",""
"uuid:6daa339a-7531-4491-9d2d-ffa0073092ea","http://resolver.tudelft.nl/uuid:6daa339a-7531-4491-9d2d-ffa0073092ea","A New High Step-Up SC-Based Grid-Tied Inverter With Limited Charging Spike for RES Applications","Marangalu, Milad Ghavipanjeh (University of Tabriz); Kurdkandi, Naser Vosoughi (San Diego State University); Monfared, Kourosh Khalaj (University of Tehran); Talebian, Iman (University of Tabriz); Neyshabouri, Yousef (Urmia University); Vahedi, H (TU Delft DC systems, Energy conversion & Storage)","","2024","Switched capacitor multilevel inverter topologies are attractive among industrial power electronics researchers due to their applicability in sustainable energy systems such as renewable energy source (RES) applications. In this paper, a new switched capacitor (SC)-based grid-tied seven-level inverter is proposed for renewable energy sources (RES) applications. The proposed inverter can generate a seven-level output voltage waveform with voltage boosting ability and a gain factor of 3. Also, the proposed topology can provide the self voltage balancing for capacitors. The most important challenge of the SC-based topologies, i.e., the capacitor charging spike current, is solved by applying a soft charging circuit in the charging loop of the capacitors. The soft charging circuit consists of an inductor and a power diode in the capacitor charging path. Using a small size inductor in the soft charging circuit, the proposed inverter can limit the input current spikes. Comprehensive experiment results and comparisons are presented to verify the accurate performance of the proposed inverter.","Capacitors; Inverters; Voltage; Topology; Switches; Inductors; Boosting; Switched-capacitor inverters; grid-tied inverter; transformer-less inverter; voltage-boosting feature; soft charging; limitation of capacitor charging current spike","en","journal article","","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:32e27cc1-23d2-4360-8e35-7fdeb58f315d","http://resolver.tudelft.nl/uuid:32e27cc1-23d2-4360-8e35-7fdeb58f315d","Ultrasmall Gold Nanoparticles Radiolabeled with Iodine-125 as Potential New Radiopharmaceutical","Wang, R. (TU Delft RST/Applied Radiation & Isotopes); Liu, Huanhuan (Zhengzhou University); Antal, Bas (Student TU Delft); Wolterbeek, H.T. (TU Delft Reactor Institute Delft); Denkova, A.G. (TU Delft RST/Applied Radiation & Isotopes)","","2024","The relatively high linear energy transfer of Auger electrons, which can cause clustered DNA damage and hence efficient cell death, makes Auger emitters excellent candidates for attacking metastasized tumors. Moreover, gammas or positrons are usually emitted along with the Auger electrons, providing the possibility of theragnostic applications. Despite the promising properties of Auger electrons, only a few radiopharmaceuticals employing Auger emitters have been developed so far. This is most likely explained by the short ranges of these electrons, requiring the delivery of the Auger emitters to crucial cell parts such as the cell nucleus. In this work, we combined the Auger emitter 125I and ultrasmall gold nanoparticles to prepare a novel radiopharmaceutical. The 125I labeled gold nanoparticles were shown to accumulate at the cell nucleus, leading to a high tumor-killing efficiency in both 2D and 3D tumor cell models. The results from this work indicate that ultrasmall nanoparticles, which passively accumulate at the cell nucleus, have the potential to be applied in targeted radionuclide therapy. Even better tumor-killing efficiency can be expected if tumor-targeting moieties are conjugated to the nanoparticles.","Auger electron; Auger therapy; iodine-125; radionuclide therapy; ultrasmall gold nanoparticle","en","journal article","","","","","","","","","","","RST/Applied Radiation & Isotopes","","",""
"uuid:66eeabab-cfa4-48bf-98c5-a7bf6dc0021b","http://resolver.tudelft.nl/uuid:66eeabab-cfa4-48bf-98c5-a7bf6dc0021b","Hydrodynamically-Driven Deposition of Mud in River Systems","Dunne, K.B.J. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Nittrouer, J. A. (Texas Tech University); Abolfazli, E. (Virginia Tech College of Engineering); Osborn, R. (Virginia Tech College of Engineering); Strom, K. B. (Virginia Tech College of Engineering)","","2024","The riverine transport and deposition of mud is the primary agent of landscape construction and evolution in many fluvial and coastal environments. Previous efforts exploring this process have raised uncertainty regarding the effects of hydrodynamic and chemical controls on the transport and deposition of mud, and thus the constructions of muddy coastal and upstream environments. As such, direct measurements are necessary to constrain the deposition of mud by river systems. Here, we combine laboratory evidence and a field investigation in the Mississippi River delta to explore the controls on the riverine transport and deposition of mud. We show that the flocculation of mud, with floc diameters greater than 10 μm, in freshwater is a ubiquitous phenomenon, causing the sedimentation of mud to be driven by changes in local hydrodynamics, and thus providing an explanation for how river systems construct landscapes through the deposition of mud in both coastal and upstream environments.","flocs; mud; mud deposition; mud transport; sedimentation","en","journal article","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:4a0305a6-4b2f-41d9-981e-7aedf6c30b5d","http://resolver.tudelft.nl/uuid:4a0305a6-4b2f-41d9-981e-7aedf6c30b5d","Zn induced surface modification of stable goethite nanoparticles for improved regenerative phosphate adsorption","Belloni, C. (TU Delft RST/Fundamental Aspects of Materials and Energy; Wetsus, Centre for Sustainable Water Technology); Korving, L. (Wetsus, Centre for Sustainable Water Technology); Witkamp, G.J. (TU Delft BT/Environmental Biotechnology; King Abdullah University of Science and Technology); Brück, E.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); Dugulan, A.I. (TU Delft RST/Fundamental Aspects of Materials and Energy; TU Delft RID/TS/Instrumenten groep)","","2024","Iron oxide-based adsorbents showed potential to reach ultra-low phosphorus (P) concentrations to prevent eutrophication and recover P. High affinity, high capacity at low P concentrations (<1 mg L−1), good stability, and reusability of the adsorbent are key factors for economic viability. In this study, nanoparticles of goethite (α-FeOOH), a highly stable phase, have been synthesized with increasing Zn2+-doping, 0–20 %at. Zn/Fe, to manipulate the surface properties, following the results of a previous work. Mössbauer spectroscopy showed preserved goethite phase and increased point of zero charge (pzc) at low Zn-doping percentages, while at higher percentages (>5%at.) co-existing phases with increased specific surface area formed. Low concentrations (0.1–10 mg L−1) batch adsorption tests showed increased P removal per unit mass with increasing doping. However, the highest pzc, affinity and P removal per unit area were observed for the 5%at. doped sample, suggesting this dopant concentration to provide the most effective surface. A regeneration test, performed at a lower pH than usual, showed preserved, even improved P desorption with increasing doping. Mössbauer spectroscopy showed that the nanoparticle phase and composition, up to 5%at., doping was preserved throughout the process. These results are promising to develop a stable effective Zn-doped goethite-based adsorbent for P recovery at ultra-low concentrations.","Adsorption; Goethite; Iron oxide; Phosphate recovery; Regeneration; Zinc doping","en","journal article","","","","","","","","","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:c1639160-332a-4289-9f2d-2e6014a8ed57","http://resolver.tudelft.nl/uuid:c1639160-332a-4289-9f2d-2e6014a8ed57","Organizational learning from construction fatalities: Balancing juridical, ethical, and operational processes","van Marrewijk, A.H. (TU Delft Design & Construction Management; BI Norwegian Business School; Vrije Universiteit Amsterdam); van der Steen, Hans (Gebr. van der Steen)","","2024","Construction work is associated with high risks of fatalities. Effective, deep and lasting learning from incidents is important for the safety of employees, but not well developed in the construction sector. We studied the organizational processes after a fatality through an auto-ethnographic field work study and found three distinct, but interrelated processes to normalize construction work; juridical, ethical and operational processes. Balanced attention to all three processes supports an effective, deep and lasting learning from incidents. We contribute to the learning from incidents literature with the insight that balanced attention for all three processes helps to learn from incidents and to improve the safety of workers. Furthermore, second victims can be important for the learning of incidents process. Finally, the findings throw new light on inadequate supervision of safety procedures, as the temporary characteristics of projects forces workers to deviate from safety procedures.","Construction fatality; Learning from incidents; Organizational processes; Safety; Second victims","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:f3d61dd2-b59b-40e6-b1a4-592c0a2e18ce","http://resolver.tudelft.nl/uuid:f3d61dd2-b59b-40e6-b1a4-592c0a2e18ce","Predictive machine learning in earth pressure balanced tunnelling for main drive torque estimation of tunnel boring machines","Glab, K. (Herrenknecht AG; Ruhr-Universität Bochum); Wehrmeyer, G. (Herrenknecht AG); Thewes, M. (Ruhr-Universität Bochum); Broere, W. (TU Delft Geo-engineering)","","2024","Designing the main drive motor capacity of Earth Pressure Balanced Tunnel Boring Machines (EPB TBMs) is a crucial task for every EPB tunnelling project. The machine needs to be equipped with sufficient power to master the geotechnical conditions of the respective project. On the other hand, overpowering the machine should be avoided for economic and sustainability reasons. Main drive torque estimation for EPB TBMs is challenging due to a multitude of impact factors and reciprocal mechanisms between the geotechnical conditions and the tunnelling process. In EPB TBM tunnelling active tunnel face support is achieved in soft and mixed ground or weak and unstable rock by generating a pressurized earth paste in the tool gap and excavation chamber of the machine. Complexity arises due to tribological and rheological effects of the active tunnel face support. These elements of uncertainty, the expected main drive torque is frequently overestimated to prevent a jamming of the machine in the ground. Mean main drive torque values often lie below 50 % of the installed nominal main drive torque capacity. In scope of this research machine learning algorithms, such as regressions, decision trees, tree ensembles, support vector machines and gaussian process regressions, have been used to predict the main drive torque. Models have been trained and tested on data collected from 9 different reference projects and validated on the data of 3 additional reference projects to test the transferability of the model. TBM diameters of the reference projects vary between 6,5 and 15,9 m and TBMs have been operating in a wide range of geotechnical boundary conditions. Different feature selection algorithms have been used and prediction results have been compared to models trained on manually selected features. Models using tree ensembles and manually selected features showed best prediction results and model performance. The machine learning approach returned a smaller and more accurate torque estimation range than traditional estimation approaches and prediction accuracy has been improved. Transparent and robust tree ensembles proofed to be suitable tools for TBM torque estimation.","Data driven modelling; EPB tunnelling; Machine learning; Torque estimation","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:9fa09968-6b60-41d5-820e-7378758d0d47","http://resolver.tudelft.nl/uuid:9fa09968-6b60-41d5-820e-7378758d0d47","Effects of pore water-rock reaction on heat extraction from the karst geothermal reservoirs: Based on the dual media model","Ji, Jiayan (China University of Petroleum - Beijing); Song, Xianzhi (China University of Petroleum - Beijing); Yi, Junlin (China University of Petroleum - Beijing); Song, G. (TU Delft Applied Geology); Wang, Gaosheng (China University of Petroleum - Beijing)","","2024","Fractures and caves are the main flow and storage channels for the karst geothermal reservoirs, and the water-rock reaction within them significantly affects the thermal performance. Most previous studies concentrated on the fractures, disregarding the impact of the pore water-rock reaction. The objective of this study is to explore the importance of pore water-rock reactions and identify the influence of various parameters when considering pore and fracture water-rock reactions. A 3D thermal-hydraulic-chemical coupling model considering dual media of pores and fractures was developed. The importance of pore water-rock reactions is demonstrated, and quantitatively characterize the effect of injection temperature (Tin), injection rate (Qin), injection concentration (cin), and ratio of the reaction-specific surface area between pore and fracture (Ap/Af) on the thermal performance. Results indicate that the pore water-rock reaction drastically affects the hydraulic conductivity and pressure difference, even leading to an opposite trend. The influence of water-rock reaction in pores on fracture deformation is regulated by Ap/Af, which augments with Ap/Af. The relative contribution of Ap/Af to production temperature, net thermal power, pressure difference, and hydraulic conductivity are 12.8%, 4.1%, 6.8%, and 13.7%, respectively. This study provides a significant guide for accurate production prediction and exploitation of karst-based geothermal reservoirs.","Fracture aperture; Karst-based thermal reserve; Pore structure; Thermal performance; Water-rock reaction","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-08","","","Applied Geology","","",""
"uuid:0f41bf25-2bbd-4564-bab3-0f85f597e91c","http://resolver.tudelft.nl/uuid:0f41bf25-2bbd-4564-bab3-0f85f597e91c","Autonomous Sensor System for Low-Capacity Wind Turbine Blade Vibration Measurement","Muxica, Diego (Universidad de los Andes, Chile); Rivera, Sebastian (TU Delft DC systems, Energy conversion & Storage; Universidad Católica de la Santísima Concepción); Orchard, Marcos E. (Universidad de Chile); Ahumada, Constanza (Universidad de Chile); Jaramillo, Francisco (Universidad de Chile); Bravo, Felipe (Universidad de los Andes, Chile); Gutiérrez, José M. (Universidad de los Andes, Chile); Astroza, Rodrigo (Universidad de los Andes, Chile)","","2024","This paper presents the design, implementation, and validation of an on-blade sensor system for remote vibration measurement for low-capacity wind turbines. The autonomous sensor system was deployed on three wind turbines, with one of them operating in harsh weather conditions in the far south of Chile. The system recorded the acceleration response of the blades in the flapwise and edgewise directions, data that could be used for extracting the dynamic characteristics of the blades, information useful for damage diagnosis and prognosis. The proposed sensor system demonstrated reliable data acquisition and transmission from wind turbines in remote locations, proving the ability to create a fully autonomous system capable of recording data for monitoring and evaluating the state of health of wind turbine blades for extended periods without human intervention. The data collected by the sensor system presented in this study can serve as a foundation for developing vibration-based strategies for real-time structural health monitoring.","accelerometer-based sensor networks; condition monitoring; data acquisition; modal analysis; structural health monitoring; wind turbines","en","journal article","","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:1cd5fd2c-b660-489f-9df4-e9e98c7a1675","http://resolver.tudelft.nl/uuid:1cd5fd2c-b660-489f-9df4-e9e98c7a1675","Changing hearts instead of changing minds – another take on climate action","Pearce, B.J. (TU Delft Policy Analysis)","","2024","This piece elaborates on a ‘new way of thinking’ (Einstein, 1946) that would contribute to overcoming the challenge of climate change and its impacts. This ‘new way’ will have us go beyond using facts and figures alone to persuade and cajole. It will have us stretching our moral imagination (Johnson, 2016) and empathising with people very different from ourselves. It will have us investing in processes of exchange which support the co-creation of knowledge and the future we want together.","climate action; implementation gap; frames; self- and collective self-efficacy; transdisciplinary approaches","en","contribution to periodical","","","","","","","","","","","Policy Analysis","","",""
"uuid:f409c5af-0686-41e5-8cbe-fc9191e42367","http://resolver.tudelft.nl/uuid:f409c5af-0686-41e5-8cbe-fc9191e42367","Synergetic urbanism: A theoretical exploration of a vertical farm as local heat source and flexible electricity user","Blom, T. (TU Delft Environmental & Climate Design); Jenkins, Andrew (University of Salford); van den Dobbelsteen, A.A.J.F. (TU Delft Environmental & Climate Design)","","2024","The urban energy transition requires innovative heating and cooling systems, as well as enhanced flexibility in electricity usage. This paper explores the theoretical potential for vertical farms to contribute to the energy transition by supplying residual heat to local district heat networks and flexible electricity usage. A stepped approach was used to design energy systems that achieve thermal energy balance through heat and cold exchange between a vertical farm and buildings within a specific Dutch neighbourhood. Furthermore, alternative lighting strategies for vertical farms were explored to reduce grid congestion and to respond to electricity price fluctuations, limiting the mismatch between electricity generation and demand. Compared to the baseline scenario, the energy system with an integrated vertical farm reduces overall energy use by 15 %, even when accounting for the farm's electricity use. By adopting intermittent lighting that is better aligned with electricity price fluctuations, the vertical farm obtained annual cost savings of 14 %. The integration of vertical farms into energy systems can, therefore, contribute to the urban energy transition by producing residual heat to balance thermal energy system and save money for growers by optimising LED operations to align with electricity price fluctuations, whilst producing fresh vegetables for the city.","Controlled environment agriculture; Energy transition; Residual heat; Heat exchange; Electricity price fluctuations; Intermittent light; Grid congestion; Flexible electricity use; Urban agriculture; Symbiosis","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:a4aa8142-b4bd-43d5-98a4-3e4bbd4b98a5","http://resolver.tudelft.nl/uuid:a4aa8142-b4bd-43d5-98a4-3e4bbd4b98a5","The role of vision in sensory integration models for predicting motion perception and sickness","Kotian, V. (TU Delft Intelligent Vehicles); Irmak, T. (TU Delft Intelligent Vehicles; University Medical Center Utrecht); Pool, D.M. (TU Delft Control & Simulation); Happee, R. (TU Delft Intelligent Vehicles)","","2024","Users of automated vehicles will engage in other activities and take their eyes off the road, making them prone to motion sickness. To resolve this, the current paper validates models predicting sickness in response to motion and visual conditions. We validate published models of vestibular and visual sensory integration that have been used for predicting motion sickness through sensory conflict. We use naturalistic driving data and laboratory motion (and vection) paradigms, such as sinusoidal translation and rotation at different frequencies, Earth-Vertical Axis Rotation, Off-Vertical Axis Rotation, Centrifugation, Somatogravic Illusion, and Pseudo-Coriolis, to evaluate different models for both motion perception and motion sickness. We investigate the effects of visual motion perception in terms of rotational velocity (visual flow) and verticality. According to our findings, the SVCI model, a 6DOF model based on the Subjective Vertical Conflict (SVC) theory, with visual rotational velocity input is effective at estimating motion sickness. However, it does not correctly replicate motion perception in paradigms such as roll-tilt perception during centrifuge, pitch perception during somatogravic illusion, and pitch perception during pseudo-Coriolis motions. On the other hand, the Multi-Sensory Observer Model (MSOM) accurately models motion perception in all considered paradigms, but does not effectively capture the frequency sensitivity of motion sickness, and the effects of vision on sickness. For both models (SVCI and MSOM), the visual perception of rotational velocity strongly affects sickness and perception. Visual verticality perception does not (yet) contribute to sickness prediction, and contributes to perception prediction only for the somatogravic illusion. In conclusion, the SVCI model with visual rotation velocity feedback is the current preferred option to design vehicle control algorithms for motion sickness reduction, while the MSOM best predicts perception. A unified model that jointly captures perception and motion sickness remains to be developed.","Comfort; Modeling; Motion perception; Motion sickness; Vision","en","journal article","","","","","","","","","","","Intelligent Vehicles","","",""
"uuid:173c3183-539e-4e5a-8db6-51e08957ce6c","http://resolver.tudelft.nl/uuid:173c3183-539e-4e5a-8db6-51e08957ce6c","Design of Wideband Flat Artificial Dielectric Lenses at mmWave Frequencies","Coco Martin, C.M. (TU Delft Tera-Hertz Sensing); Hu, Weiya (Student TU Delft); Cavallo, D. (TU Delft Tera-Hertz Sensing)","","2024","This work aims to provide guidelines on the design of wideband flat lenses based on artificial dielectric layers (ADLs). Planar lenses based on metasurfaces are typically narrowband, due to the phase wrapping over the period of 2\pi that is strongly frequency-dependent. On the contrary, true-time-delay (TTD) planar lenses, which do not resort to phase discontinuities, can achieve large bandwidths. One convenient way to design wideband TTD lenses is by means of ADLs, which are stacks of subwavelength-period patch arrays embedded in a host medium to increase its effective permittivity. Tradeoffs including bandwidth, focal ratio, lens diameter, and thickness are discussed and related to the manufacturing constraints of artificial dielectrics, such as the smallest features realizable in printed circuit board (PCB) technology, which define the maximum achievable effective permittivity. An example of design is also presented, operating from 30 to 60 GHz and experimentally validated.","artificial dielectrics; flat lenses; true-time-delay lens; ray tracing; wideband lenses","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Tera-Hertz Sensing","","",""
"uuid:4f72ee48-af59-4442-9768-69c1133ef133","http://resolver.tudelft.nl/uuid:4f72ee48-af59-4442-9768-69c1133ef133","ALBERO: Agile Landing on Branches for Environmental Robotics Operations","Zheng, L. (TU Delft Control & Simulation); Hamaza, S. (TU Delft Control & Simulation)","","2024","Drones have been increasingly used in various domains, including ecological monitoring in forests. However, the endurance and noise of drones have limited their deployment to short flight missions above canopies. To address these limitations, we introduce ALBERO: a framework comprising a mechanical solution and an optimal planner to realise agile quadrotor perching on tree branches of steep incline. The gripper features an ultra-fast active mechanism inspired by birds' claws that enables quadrotors to perch swiftly on randomly-oriented tree branches. By perching, the drone can preserve energy for extended periods of time, while silently gathering forest data in the canopy. The intrinsic properties of the gripper allow for extra flexibility in size, surface roughness and shape imperfections of natural perches, such as those found in the wild. The gripper also has good scalability properties and can be easily matched to different drones' sizes. The biggest advantage of this novel design lays in its ability to close reactively and ultra-fast (67ms) on the large gripper, 42ms on the small gripper), enabling the quadrotor to perform agile perching manoeuvres from different angles and at different approach speeds. ALBERO's software module comprises of a trajectory planning algorithm adapted for branch perching, ensuring that the drone can perch on inclined cylindrical targets from any starting location in the proximity of the branch. These requirements translate in stringent positioning and orientation accuracy, but they enable the drone to land dynamically from a variety of positions within the forest.","Agile Motion Planning; Agile Perching; Drones; Environmental Monitoring; Gears; Gripper Design; Grippers; Quadrotors; Servomotors; Springs; Steel; UAVs Applications","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-08","","","Control & Simulation","","",""
"uuid:afdc3565-30a8-4a0a-8bd6-5e67627b05d4","http://resolver.tudelft.nl/uuid:afdc3565-30a8-4a0a-8bd6-5e67627b05d4","Multipath Exploitation for Human Activity Recognition using a Radar Network","Guendel, R.G. (TU Delft Microwave Sensing, Signals & Systems); Kruse, N.C. (TU Delft Microwave Sensing, Signals & Systems); Fioranelli, F. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2024","In this study, the problem of multipath in radar sensor networks for human activity recognition (HAR) has been examined. Traditionally considered as a source of additional clutter, the multipath is being investigated for its potential to be exploited through the creation of virtual radar nodes. These virtual nodes are conceptualized to observe targets from aspect angles that differ from those of physically existing radars. To realize this idea, an innovative processing pipeline is proposed that extracts information from multipath signals to improve HAR. The pipeline isolates and tracks the line-of-sight (LOS) and multipath components of a moving human target performing continuous sequences of activities observed by a network of three radar sensors. Furthermore, the method has been verified with experimental data consisting of six activities and 14 volunteers by comparing classification metrics with the use of a single radar as well as only the LOS components of the three radars in the network. A 12-layer convolutional neural network (CNN) classifier has been designed to operate on range-Doppler (RD) images derived from the LOS and multipath components, extracted by the proposed method. A substantial performance improvement using the leave-one-person-out (L1Po) test set is demonstrated in the order of +11% by exploiting a multiradar network with its LOS and multipath components.","radar signal processing; radar multipath; multipath; human activity recognition; distributed radar; hierarchical clustering; clustering; multilateration; trilateration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-16","","","Microwave Sensing, Signals & Systems","","",""
"uuid:345b1ae0-59f3-452f-8f5f-40f57587252b","http://resolver.tudelft.nl/uuid:345b1ae0-59f3-452f-8f5f-40f57587252b","Online Condition Monitoring Methodology for Power Electronics Package Reliability Assessment","Martin, H.A. (TU Delft Electronic Components, Technology and Materials; Chip Integration Technology Center (CITC)); Smits, Edsger C.P. (Chip Integration Technology Center (CITC)); Poelma, René H. (TU Delft Electronic Components, Technology and Materials; Nexperia B.V.); van Driel, W.D. (TU Delft Electronic Components, Technology and Materials; Signify); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2024","This article introduces an online condition monitoring strategy that utilizes a transient heat pulse to detect package thermal performance degradation. The metric employed is the temperature-dependent transient thermal impedance ""Zth(t, Tamb).""The proposed methodology offers quantitative insights into package thermal performance degradation and effectively pinpoints the presence of multiple failure mechanisms. A thermal test chip assembled in a power quad flat no-lead package is used in this study to demonstrate the methodology. The packaged devices are first characterized to determine the transient pulse duration, a critical parameter to monitor a specific region of interest. Subsequently, package thermal performance degradation is continuously monitored online during thermomechanical cycling lifetime experiments. The validity of the measurement results is later confirmed through acoustic imaging and cross-sectional analysis. The changes observed in Zth(t, Tamb) over thermal cycling correspond to the delamination of the active metal layers on the die and cohesive failure on the die attach. This article further includes a comparative summary, highlighting the distinctions between the proposed and industry-standard test methods. In conclusion, the importance of online condition monitoring to detect early signs of failure is emphasized, and the proposed methodology s practical applicability in real-life scenarios is briefly discussed.","Electronic packaging; Temperature measurement; Semiconductor device measurement; Temperature sensors; Electrical resistance measurement; Transient analysis; Thermal Cycling; Silver Sintering; Transient Thermal Impedance; Thermal Test Chips; Application-driven Reliability Qualification","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-11","","","Electronic Components, Technology and Materials","","",""
"uuid:75f56794-1226-4ead-bd79-ffb9d591b56d","http://resolver.tudelft.nl/uuid:75f56794-1226-4ead-bd79-ffb9d591b56d","Predicting cell population-specific gene expression from genomic sequence","Michielsen, L.C.M. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center); Reinders, M.J.T. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center); Mahfouz, A.M.E.T.A. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center)","","2024","Most regulatory elements, especially enhancer sequences, are cell population-specific. One could even argue that a distinct set of regulatory elements is what defines a cell population. However, discovering which non-coding regions of the DNA are essential in which context, and as a result, which genes are expressed, is a difficult task. Some computational models tackle this problem by predicting gene expression directly from the genomic sequence. These models are currently limited to predicting bulk measurements and mainly make tissue-specific predictions. Here, we present a model that leverages single-cell RNA-sequencing data to predict gene expression. We show that cell population-specific models outperform tissue-specific models, especially when the expression profile of a cell population and the corresponding tissue are dissimilar. Further, we show that our model can prioritize GWAS variants and learn motifs of transcription factor binding sites. We envision that our model can be useful for delineating cell population-specific regulatory elements.","sequence to prediction models; single-cell RNA-sequencing; gene expression prediction; transcriptional regulation; cell populations","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:975b60af-4add-47d7-9776-a5c2f97d89ed","http://resolver.tudelft.nl/uuid:975b60af-4add-47d7-9776-a5c2f97d89ed","Opportunities of Natural Resources Making Buildings More Resilient","van den Engel, P.J.W. (TU Delft Environmental & Climate Design)","","2024","An overview is given of the state-of-the-art of natural and hybrid ventilation in buildings in general. The focus of this paper is on boundary conditions for openable windows. As a case study the Co Creation Centre at the TU-Delft is discussed. Occupants live in their own houses and often in an office or other working environments as well. Due to the development of working on a distance, accelerated by the COVID-pandemics, they generally have more choice which environment is the best. That is why a holistic approach is necessary for buildings in general and houses. Natural ventilation offers a wide range of low-cost opportunities to realize the required thermal comfort and need of fresh air. Boundary conditions for ventilation are the limitation of cooling and heating by intelligent building physical design of the façade or roof, with better balancing heat loss due to transmission and heat gain by solar access. In this field there is still a lack of knowledge at many professionals. In most cases natural ventilation has to be supported by robust mechanical systems. Effective integration is a rather new field of research, learning from the past. Current examples of integration are discussed, in which BMS-systems play a key role.","Natural and hybrid ventilation; Openable windows; Covid protection; Resilience concept; Robustness; Natural resources; Buildings; Natural ventilation; Climate","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:21c03aae-b8cf-4eaa-b1f0-683dfa3ecfa3","http://resolver.tudelft.nl/uuid:21c03aae-b8cf-4eaa-b1f0-683dfa3ecfa3","Coupling agent-based modelling and life cycle assessment for a behaviour-driven evaluation of SAEVs","Vilaça, M.V. (Universidade de Aveiro; Intelligent Systems Associate Laboratory (LASI)); Correia, Gonçalo (TU Delft Transport and Planning); Coelho, Margarida C. (Universidade de Aveiro; Intelligent Systems Associate Laboratory (LASI))","","2024","Shared Automated Electric Vehicles (SAEVs) are poised to revolutionize future transportation. However, potential drawbacks, including increased vehicle usage and the projected shorter vehicle lifespan, introduce critical factors that may impact efficiency and environmental benefits. This research introduces a framework that integrates Agent-Based Modelling (ABM) with Life Cycle Assessment (LCA) for a behaviour-driven SAEV assessment. The ABM simulates regional SAEV operations, informing the LCA of pre- and post-integration scenarios. Sensitivity analysis on fleet sizes, system performance metrics, and Global Warming Potential (GWP) reference values are performed. Findings demonstrate that SAEVs significantly decrease the fleet size and total travel distance by raising the average travel per vehicle. SAEVs integration yields a 75–86% daily GWP reduction without significantly compromising user experience. Over 30 years, fleet replacement needs due to inadequate fleet sizing raised GWP by 170%. Balancing short and long-term environmental impact requires optimizing fleet size to achieve sustainable and efficient service delivery.","Agent-based modelling (ABM); Life cycle assessment (LCA); Sharedautomated and electric vehicles (SAEVs)","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:0db46967-fec3-4fe3-91d8-a442fa9797ba","http://resolver.tudelft.nl/uuid:0db46967-fec3-4fe3-91d8-a442fa9797ba","A copula-based model to describe the uncertainty of overtopping variables on mound breakwaters","Mares Nasarre, P. (TU Delft Hydraulic Structures and Flood Risk); van Gent, M.R.A. (TU Delft Coastal Engineering; Deltares); Morales Napoles, O. (TU Delft Applied Probability)","","2024","Rising sea levels caused by climate change are increasing the risk of overtopping on coastal structures. Moreover, there is a growing societal concern about the visual impact of these structures, which leads to the lowering of their crest freeboards. In previous studies, safety during overtopping events was assessed considering the overtopping layer thickness (hc), the overtopping flow velocity (uc) and the individual wave overtopping volume (V). Existing models in the literature to estimate hc, uc and V on mound breakwater crests are mainly deterministic, involve a chain of successive estimations leading to accumulated errors and/or do not account for the dependencies between hc, uc and V. This study proposes a model to describe the joint probability distribution of hc, uc and V based on bivariate copulas. Experimental data from small-scale 2D physical tests conducted on mound breakwaters with three armor layers (single-layer Cubipod®, and double-layer cubes and rocks) in depth-limited breaking wave conditions on two mild bottom slopes and dimensionless crest freeboards between 0.33 and 3.20 is used. Lognormal distribution functions are proposed for each variable and a multivariate dependence model is developed through a one-tree vine-copula. The parameters of this model are quantified directly using wave characteristics and the structure geometry minimizing the accumulated errors in the final predictions. The application of the model is illustrated by computing the probability of not fulfilling at least a tolerability limit for one of the studied variables (OR probability). The OR probability is computed both considering the dependence and assuming independence between the variables and a significant difference is obtained. It is concluded that by accounting for the multivariate dependence between the variables, it is possible to reduce the crest freeboard and, thus, achieve a more economic design within the required safety level.","Copula; Dependence; Mound breakwater; Overtopping; Overtopping flow velocity; Overtopping layer thickness; Overtopping volume; Probability; Uncertainty","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:4ae56e89-0595-4e70-bac0-6bc8f070d169","http://resolver.tudelft.nl/uuid:4ae56e89-0595-4e70-bac0-6bc8f070d169","Vertical dynamic measurements of a railway transition zone: a case study in Sweden","Unsiwilai, S. (TU Delft Railway Engineering); Shen, C. (TU Delft Railway Engineering); Zeng, Y. (TU Delft Railway Engineering); Wang, L. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","","2024","This study presents a measuring framework for railway transition zones using a case study on the Swedish line between Boden and Murjek. The final goal is to better understand the vertical dynamics of transition zones using hammer tests, falling weight measurements, and axle box acceleration (ABA) measurements. Frequency response functions (FRFs) from hammer tests indicate two track resonances, for which the FRF magnitudes on the plain track are at least 30% lower than those at the abutment. The falling weight measurements indicate that the track on the bridge has a much higher deflection than the track on the embankment. Two features from ABA signals, the dominant spatial frequency and the scale average wavelet power, show variation along the transition zone. These variations indicate differences in track conditions per location. Finally, the ABA features in the range of 1.05–2.86 m−1 are found to be related to the track resonance in the range of 30–60 Hz. The findings in this paper provide additional support for physically interpreting train-borne measurements for monitoring transition zones.","Axle box acceleration; Impact excitation; Railway bridge; Railway track vertical dynamic; Railway transition zone","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:7842c753-5cbb-47eb-934c-62786bcd0ec8","http://resolver.tudelft.nl/uuid:7842c753-5cbb-47eb-934c-62786bcd0ec8","Multi-epoch PPP-RTK corrections: temporal characteristics, pitfalls and user-impact","Psychas, D.V. (European Space Agency (ESA)); Khodabandeh, A. (University of Melbourne); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; University of Melbourne; Curtin University of Technology)","","2024","PPP-RTK corrections, aiding GNSS users to achieve single-receiver integer ambiguity-resolved parameter solutions, are often estimated in a recursive manner by a provider. Such recursive, multi-epoch, estimation of the corrections relies on a set of S-basis parameters that are chosen by the provider so as to make the underlying measurement setup solvable. As a consequence, the provider can only estimate estimable forms of the corrections rather than the original corrections themselves. It is the goal of the present contribution to address the consequence of the corrections’ dependency on the provider’s S-basis, showcasing the characteristics of their multi-epoch solutions, thereby identifying potential pitfalls which the PPP-RTK user should avoid when evaluating such solutions. To this end, we develop a simulation platform that allows one to have full control over the properties of PPP-RTK corrections and demonstrate various misleading temporal behaviors that exist when interpreting the multi-epoch solutions of their estimable forms. The roles of the correction latency and time correlation in the multi-epoch user positioning performance are quantified, while the deviation of the user-reported positioning precision description from its user-actual counterpart is measured under a misspecified user stochastic model.","Correction latency; Global navigation satellite systems (GNSS); Integer ambiguity resolution (IAR); Multi-epoch filtering; PPP-RTK corrections; Time correlation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-19","","","Mathematical Geodesy and Positioning","","",""
"uuid:8e65b670-0dec-4743-9ae3-639d0abfa717","http://resolver.tudelft.nl/uuid:8e65b670-0dec-4743-9ae3-639d0abfa717","On the scalability of helium-filled soap bubbles for volumetric PIV","Grille Guerra, A. (TU Delft Aerodynamics); Scarano, F. (TU Delft Aerodynamics); Sciacchitano, A. (TU Delft Aerodynamics)","","2024","The scalability of experiments using PIV relies upon several parameters, namely illumination power, camera sensor and primarily the tracers light scattering capability. Given their larger cross section, helium-filled soap bubbles (HFSB) allow measurements in air flows over a significantly large domain compared to traditional oil or fog droplets. Controlling their diameter translates into scalability of the experiment. This work presents a technique to extend the control of HFSB diameter by geometrical variations of the generator. The latter expands the more limited range allowed by varying the relative helium-air mass flow rates. A theoretical model predicts the bubble size and production rate, which is verified experimentally by high-speed shadow visualization. The overall range of HFSB produced in a stable (bubbling) regime varies from 0.16 to 2.7 mm. Imaging by light scattering of such tracers is also investigated, in view of controversies in the literature on whether diffraction or geometrical imaging dominate the imaging regime. The light scattered by scaled HFSB tracers is imaged with a high-speed camera orthogonal to the illumination. Both the total energy collected on the sensor for a single tracer, as well as its peak intensity, are found to preserve scaling with the square of the diameter at object magnification of 10–1 or below, typical of PIV experiments. For large-scale volumetric applications, it is shown that varying the bubble diameter allows increasing both the measurement domain as well as the working distance of the imagers at 10 m and beyond. A scaling rule is proposed for the latter.","","en","journal article","","","","","","","","","","","Aerodynamics","","",""
"uuid:737781a6-f3d8-4ab3-ac6d-138478935ef6","http://resolver.tudelft.nl/uuid:737781a6-f3d8-4ab3-ac6d-138478935ef6","Building a Mycenaean chamber tomb catalogue from terrestrial laser scan data","Gutierrez, Ivan (University of Stavanger); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing); Watson, Lisa (University of Stavanger); Shelton, Kim (University of California Berkeley)","","2024","Detailed 3D information on vulnerable archaeological sites can document cultural heritage and contribute to its preservation. The Late Bronze Age Mycenaean cemetery of Aidonia, Greece, is a representative case of a vulnerable site. Tomb looting has occurred sporadically since the 1970s, when the Greek government was made aware of the site. Anthropogenic activities and natural denudation may affect the loss of structural integrity of tombs. In this contribution, terrestrial laser scanning and geosciences are combined to document the vulnerable cemetery through the generation of a tomb catalogue. The emphasis is on techniques applied to point clouds to extract architectural elements. The catalogue consists of 208 architectural and geological measurements, 112 qualitative observations, maps, and point clouds images displaying the architecture of 16 tombs. The tombs are mainly orientated northeast-southwest and northwest-southeast, and their average total length is 13 m. The average volume of chambers with preserved roofs is 46 m3.","Catalogue; Digital documentation; Mycenaean; Segmentation; Terrestrial laser scanning; Tombs","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:d449fc2b-05c5-4f9b-96f4-9c626a9cecab","http://resolver.tudelft.nl/uuid:d449fc2b-05c5-4f9b-96f4-9c626a9cecab","Frameworks for multi-system innovation analysis from a sociotechnical perspective: A systematic literature review","Bakhuis, J.J. (TU Delft Energie and Industrie); Kamp, L.M. (TU Delft Energie and Industrie); Barbour, Natalia (University of Central Florida); Chappin, E.J.L. (TU Delft Energie and Industrie)","","2024","This paper systematically reviews the literature on sociotechnical multi-system innovation frameworks that broaden the usual focus on one sociotechnical system to encompass influences from multiple systems. The review includes 75 peer-reviewed papers that span a broad range of energy-demanding systems and mainly build upon the core frameworks of the Multi-level Perspective (MLP) and Technological Innovation Systems (TIS). The analysis identifies three key aspects to consider in multi-system frameworks. The first aspect is the importance of considering the overarching directionality of multiple sociotechnical systems and how they influence each other. The second is to explicitly analyse the phase of each transitioning system. The third aspect is a need for explicit system configuration analysis. This includes analysing the value chain and the number and types of sectors linked to it, typifying the distinct characteristics of sectors internally and how they interact, and analysing complementary or competitive technologies. The paper concludes by providing recommendations for future research, with a particular focus on the further development of new multi-system frameworks that include one or more of the prior-mentioned three key takeaways. Firstly, focusing on dynamics within multi-system niches. Secondly, performing actor-level analysis, including demand-side analysis. Finally, applying quantitative methods, such as computer simulation modelling.","Converging infrastructures; Innovation systems; Multi-level perspective; Multi-system; Sector coupling; Sustainability transition","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:10b904b9-67c5-4c1e-b768-238268230391","http://resolver.tudelft.nl/uuid:10b904b9-67c5-4c1e-b768-238268230391","Not a single path to success: alternative HRM configurations for well-performing small and medium-sized hotels","Zografou, I. (Athens University of Economics and Business); Galanaki, E. (Athens University of Economics and Business); Pachos-Fokialis, N. (TU Delft Economics of Technology and Innovation); Deligianni, I. (Athens University of Economics and Business)","","2024","Purpose: Previous literature has identified human resources as a key source of competitive advantage in organizations of all sizes. However, Small and Medium-sized Enterprises (SMEs) face difficulty in comprehensively implementing all recommended Human Resource Management (HRM) functions. In this study, we shed light on the field of HRM in SMEs by focusing on the context of Greek Small and Medium-sized Hotels (SMHs), which represent a dominant private sector employer across the country. Design/methodology/approach: Using a fuzzy-set qualitative comparative analysis (fsQCA) and 34 in-depth interviews with SMHs' owners/managers, we explore the HRM conditions leading to high levels of performance, while taking into consideration the influence of internal key determinants. Findings: We uncover three alternative successful HRM strategies that maximize business performance, namely the Compensation-based performers, the HRM developers and the HRM investors. Each strategy fits discreet organizational characteristics related to company size, ownership type and organizational structure. Originality/value: To the best of the authors' knowledge this is among the first empirical studies that examine different and equifinal performance-enhancing configurations of HRM practices in SMHs.","Business performance; Fuzzy-set qualitative comparative analysis (fsQCA); HRM configurations; Human resource management (HRM); Small and medium-sized enterprises (SMEs); Small and medium-sized hotels (SMHs)","en","journal article","","","","","","","","","","","Economics of Technology and Innovation","","",""
"uuid:6185bc47-eeb4-4c20-b544-eec43fe2fdaa","http://resolver.tudelft.nl/uuid:6185bc47-eeb4-4c20-b544-eec43fe2fdaa","AI for crisis decisions","Comes, M. (TU Delft Transport and Logistics)","","2024","Increasingly, our cities are confronted with crises. Fuelled by climate change and a loss of biodiversity, increasing inequalities and fragmentation, challenges range from social unrest and outbursts of violence to heatwaves, torrential rainfall, or epidemics. As crises require rapid interventions that overwhelm human decision-making capacity, AI has been portrayed as a potential avenue to support or even automate decision-making. In this paper, I analyse the specific challenges of AI in urban crisis management as an example and test case for many super wicked decision problems. These super wicked problems are characterised by a coincidence of great complexity and urgency. I will argue that from this combination, specific challenges arise that are only partially covered in the current guidelines and standards around trustworthy or human-centered AI. By following a decision-centric perspective, I argue that to solve urgent crisis problems, the context, capacities, and networks need to be addressed. AI for crisis response needs to follow dedicated design principles that ensure (i) human control in complex social networks, where many humans interact with AI; (ii) principled design that considers core principles of crisis response such as solidarity and humanity; (iii) designing for the most vulnerable. As such this paper is meant to inspire researchers, AI developers and practitioners in the space of AI for (urban) crisis response – and other urgent and complex problems that urban planners are confronted with.","Crisis management; Decision theory; Human-AI interaction; Human-centred AI; Responsible AI","en","journal article","","","","","","","","","","","Transport and Logistics","","",""
"uuid:ed03fa19-93fd-43f8-ad8c-1125e3205921","http://resolver.tudelft.nl/uuid:ed03fa19-93fd-43f8-ad8c-1125e3205921","Policy Analysis of Coastal-Based Special Economic Zone Development Using System Dynamics","Moeis, Armand Omar (Universitas Indonesia); Gita, Agatha Ayu (Universitas Indonesia); Destyanto, A.R. (TU Delft Policy Analysis; Universitas Indonesia); Rahman, Irvanu (Universitas Indonesia; Karlsruhe Institut für Technologie); Hidayatno, Akhmad (Universitas Indonesia); Zagloel, Teuku Yuri (Universitas Indonesia)","","2024","Special Economic Zone (SEZ) development is becoming a preferable policy by the Indonesian government to boost economic growth in less-developed local regions. This is because of the promise that SEZ could attract investment and job creation based on local competitive commodities. One of these areas is Bitung SEZ, North Sulawesi - Indonesia, a coastal-based SEZ, as its strategic position for logistics, fishery resources, and coconut plantation. To explore the promise of growth proposed by developing SEZ in Bitung, we developed a Systems Dynamics model of the interaction between economic growth, social development, and environmental impacts. Based on the model understanding and development, we identified three factors the Indonesian government should improve: coconut plantation productivity, fisheries ship management, and education index. With these three factors in mind, several policy options were tested in the model, resulting in a more substantial impact than the business-as-usual condition.","Policy analysis; Special Economic Zone (SEZ); System dynamics","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:d6fbe041-5638-4d9c-b751-c067c10add47","http://resolver.tudelft.nl/uuid:d6fbe041-5638-4d9c-b751-c067c10add47","The One Step Malliavin scheme: new discretization of BSDEs implemented with deep learning regressions","Négyesi, B. (TU Delft Numerical Analysis); Andersson, Kristoffer (Centrum Wiskunde & Informatica (CWI)); Oosterlee, Cornelis W. (Universiteit Utrecht)","","2024","A novel discretization is presented for decoupled forward–backward stochastic differential equations (FBSDE) with differentiable coefficients, simultaneously solving the BSDE and its Malliavin sensitivity problem. The control process is estimated by the corresponding linear BSDE driving the trajectories of the Malliavin derivatives of the solution pair, which implies the need to provide accurate Γ estimates. The approximation is based on a merged formulation given by the Feynman–Kac formulae and the Malliavin chain rule. The continuous time dynamics is discretized with a theta-scheme. In order to allow for an efficient numerical solution of the arising semidiscrete conditional expectations in possibly high dimensions, it is fundamental that the chosen approach admits to differentiable estimates. Two fully-implementable schemes are considered: the BCOS method as a reference in the one-dimensional framework and neural network Monte Carlo regressions in case of high-dimensional problems, similarly to the recently emerging class of Deep BSDE methods (Han et al. (2018 Solving high-dimensional partial differential equations using deep learning. Proc. Natl. Acad. Sci., 115, 8505–8510); Huré et al. (2020 Deep backward schemes for high-dimensional nonlinear PDEs. Math. Comp., 89, 1547–1579)). An error analysis is carried out to show L2 convergence of order, under standard Lipschitz assumptions and additive noise in the forward diffusion. Numerical experiments are provided for a range of different semilinear equations up to dimensions, demonstrating that the proposed scheme yields a significant improvement in the control estimations.","backward stochastic differential equations; Malliavin calculus; deep BSDE; neural networks; BCOS; gamma estimates","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-26","","","Numerical Analysis","","",""
"uuid:ec4c9247-2b30-417a-a01e-ab49c9f316de","http://resolver.tudelft.nl/uuid:ec4c9247-2b30-417a-a01e-ab49c9f316de","Ten simple rules for pushing boundaries of inclusion at academic events","Mackenzie Hall, Siobhan (University of Oxford; Deep Learning Indaba); Kochin, Daniel (University of Oxford); Lenay Lewers, Kristen (University of Colorado Boulder); Abdelhack, Mohamed (Centre for Addiction and Mental Health); Alphonse, Juno Felecia Michael (University of Oxford); Ung, Visotheary (Centre National de la Recherche Scientifique (CNRS)); El-Gebali, Sara (SciLifeLab-Data Centre); Plomp, E. (TU Delft Management Support); Sharan, Malvika (OLS; The Alan Turing Institute)","","2024","Inclusion at academic events is facing increased scrutiny as the communities these events serve raise their expectations for who can practically attend. Active efforts in recent years to bring more diversity to academic events have brought progress and created momentum. However, we must reflect on these efforts and determine which underrepresented groups are being disadvantaged. Inclusion at academic events is important to ensure diversity of discourse and opinion, to help build networks, and to avoid academic siloing. All of these contribute to the development of a robust and resilient academic field. We have developed these Ten Simple Rules both to amplify the voices that have been speaking out and to celebrate the progress of many Equity, Diversity, and Inclusivity practices that continue to drive the organisation of academic events. The Rules aim to raise awareness as well as provide actionable suggestions and tools to support these initiatives further. This aims to support academic organisations such as the Deep Learning Indaba, Neuromatch Academy, the IBRO-Simons Computational Neuroscience Imbizo, Biodiversity Information Standards (TDWG), Arabs in Neuroscience, FAIRPoints, and OLS (formerly Open Life Science). This article is a call to action for organisers to reevaluate the impact and reach of their inclusive practices.","","en","journal article","","","","","","","","","","","Management Support","","",""
"uuid:e2a153e5-7206-4157-872a-f8bb67423a2d","http://resolver.tudelft.nl/uuid:e2a153e5-7206-4157-872a-f8bb67423a2d","Energy use and greenhouse gas emissions of traction alternatives for regional railways","Kapetanović, M. (TU Delft Transport and Planning); Nunez, Alfredo (TU Delft Railway Engineering); van Oort, N. (TU Delft Transport and Planning); Goverde, R.M.P. (TU Delft Transport and Planning)","","2024","This paper presents a method for estimating Well-to-Wheel (WTW) energy use and greenhouse gas (GHG) emissions attributed to the advanced railway propulsion systems implemented in conjunction with different energy carriers and their production pathways. The analysis encompasses diesel-electric multiple unit vehicles converted to their hybrid-electric, plug-in hybrid-electric, fuel cell hybrid-electric or battery-electric counterparts, combined with biodiesel or hydrotreated vegetable oil (HVO) as the first and second generation biofuels, liquefied natural gas (LNG), hydrogen and/or electricity. The method is demonstrated using non-electrified regional railway network with heterogeneous vehicle fleet in the Netherlands as a case. Battery-electric system utilizing green electricity is identified as the only configuration leading to emission-free transport while offering the highest energy use reduction by 65–71% compared to the current diesel-powered hybrid-electric system. When using grey electricity based on the EU2030 production mix, these savings are reduced to about 27–39% in WTW energy use and around 68–73% in WTW GHG emissions. Significant reductions in overall energy use and emissions are obtained for the plug-in hybrid-electric concept when combining diesel, LNG, or waste cooking oil-based HVO with electricity. The remaining configurations that reduce energy use and GHG emissions are hybrid-electric systems running on LNG or HVO from waste cooking oil. The latter led to approximately 88% lower WTW emissions than the baseline for each vehicle type. When produced from natural gas or EU2030-mix-based electrolysis, hydrogen negatively affected both aspects, irrespective of the prime mover technology. However, when produced via green electricity, it offers a GHG reduction of approximately 90% for hybrid-electric and fuel cell hybrid-electric configurations, with a further reduction of up to 92–93% if combined with green electricity in plug-in hybrid-electric systems. The results indicate that HVO from waste cooking oil could be an effective and instantly implementable transition solution towards carbon–neutral regional trains, allowing for a smooth transition and development of supporting infrastructure required for more energy-efficient and environment-friendly technologies.","Advanced propulsion systems; Energy use; Greenhouse gas emissions; Regional railway; Renewable fuels; Well-to-Wheel","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:a162b9fa-7654-4999-b7eb-5189b9f20589","http://resolver.tudelft.nl/uuid:a162b9fa-7654-4999-b7eb-5189b9f20589","Fatigue crack growth characterization of composite-to-steel bonded interface using ENF and 4ENF tests","Feng, W. (TU Delft Steel & Composite Structures); Moreira Arouche, M. (TU Delft Steel & Composite Structures); Pavlovic, M. (TU Delft Steel & Composite Structures)","","2024","In this paper, mode II fatigue crack growth properties of the composite-to-steel interface are characterised through different test configurations, namely ENF and 4ENF tests. Different loading types including force control and displacement control methods are compared. An innovative shear strain based method is proposed for monitoring the mode II crack growth at the bi-material interface through Digital Image Correlation (DIC). A 3D finite element model with Virtual Crack Closure Technique (VCCT) is built and used for obtaining the strain energy release rate (SERR) to investigate the effect of geometrical nonlinearity, friction at the interface and steel yielding, as well as to verify the mode mixity. The results show that the standard 3-point bending ENF specimen can be unstable under force control and sweeps narrow SERR range by a single test under displacement control. The 4-point bending 4ENF test shows stable crack propagation and clear SERR developing trend. More pronounced geometrical nonlinearity and friction effect exist for 4ENF test which can be considered when interpreting the Paris curves by a nonlinear finite element model.","DIC; ENF test; Fatigue debonding; Paris curves; VCCT","en","journal article","","","","","","","","","","","Steel & Composite Structures","","",""
"uuid:2d7c774b-a9b7-42af-857d-0a2057e97c03","http://resolver.tudelft.nl/uuid:2d7c774b-a9b7-42af-857d-0a2057e97c03","Recovery of sulfuric acid and ammonia from scrubber effluents using bipolar membrane electrodialysis: Effect of pH and temperature","Narayen, D. (TU Delft Sanitary Engineering); VAN Berlo, E.M.C. (TU Delft Sanitary Engineering); van Lier, J.B. (TU Delft Sanitary Engineering); Spanjers, H. (TU Delft Sanitary Engineering)","","2024","Simulated ammonium sulfate scrubber effluent was treated using bipolar membrane electrodialysis (BPMED) to recover sulfuric acid for reuse in the scrubber, and ammonium hydroxide as a product, without using any chemicals. The effect of pH and temperature of the feed solution on the energy consumption of the BPMED and the purity of the recovered acid and base were investigated in batch experiments. Experiments were conducted during a 3-hour period using a scrubber effluent with the following characteristics: 50 g/L ammonium sulfate, pH ranging from 1 to 5 and temperature ranging from 20 °C to 30 °C. The energy consumption at pH 5 was lower than that at pH 1, i.e., 6.9 MJ/kg SO42- and 7.7 MJ/kg SO42-, respectively. The purity of the acid recovered from the feed solution with a pH of 5 was 36 %, whereas the feed with a pH of 1 resulted in an acid purity of 72 %. These values corresponded to a mass of ammonia diffusion of 6.9 g and 2.3 g, respectively. The purity of the base recovered from the feed with a pH of 5 was 84 %, whereas this was 69 % for the feed with a pH of 1. Higher temperature of the feed solution, i.e., 30 °C compared to 20 °C, resulted in a lower energy consumption: 7.1 MJ/kg SO42- compared to 9.5 MJ/kg SO42−, respectively. The temperature had a very limited effect on the acid and base purities, with values ranging from 80 % to 82 % for the acid, and from 33 % to 36 % for the base. Our study demonstrated the effective application of BPMED for the treatment of simulated acidic scrubber effluent, with simultaneous recovery of ammonia and sulfuric acid.","Ammonia recovery; Bipolar membrane electrodialysis; pH; Sulfuric acid recovery; Temperature","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:c602540a-e3f6-4881-aa0d-ac0d01026d39","http://resolver.tudelft.nl/uuid:c602540a-e3f6-4881-aa0d-ac0d01026d39","Application of a simplified model for assessing particle removal in dissolved air flotation (DAF) systems: Experimental verification at laboratory and full-scale level","Piaggio, A.L. (TU Delft Sanitary Engineering); Smith, Geo (Nijhuis Saur Industries); de Kreuk, M.K. (TU Delft Water Management); Lindeboom, R.E.F. (TU Delft Laboratory Water Management)","","2024","Particle-bubble collisions in dissolved air flotation (DAF) systems play a crucial role in the removal of total suspended solids (TSS). DAF particle-bubble collision models incorporate factors such as particle diameters, charge and density, bubble diameters, and collision factors. The challenge lies in accounting for the wide range of particle and bubble sizes and obtaining complex model inputs. To address this, a simplified model for TSS removal in DAF units was established using low-cost laboratory measurements, including particle size distribution and density. Additionally, microbubble diameter profiles were derived from bubble velocities using particle image velocimetry software (PIV). Six independent variables, encompassing influent particle characteristics (such as particle size distribution and density) and DAF running characteristics (temperature, contact zone detention time, inflow and recycle flows), were employed in the simplified model. The model's accuracy was evaluated using a laboratory-scale DAF system with two different influents: Delft canal water and anaerobic sludge. The predicted TSS removal from the simplified model aligned well with the laboratory-scale DAF results, yielding removal efficiencies of 68 ± 1 % and 77 ± 3 % for Delft canal water and anaerobic sludge, respectively. Furthermore, when the simplified model was applied to two full-scale DAF systems, it successfully identified an underperforming system (DAF2) with a TSS removal efficiency of 91 %, contrasting with the theoretical removal model-predicted efficiency of 98 %. This study highlights the utility of combining bubble size distribution measured by PIVlab and particle size distribution obtained using FIJI-ImageJ as an economical and efficient approach to acquiring the necessary inputs for predicting TSS removal in DAF systems.","Dissolved air flotation (DAF); Particle image velocimetry (PIV); Simplified model; Suspended solids","en","journal article","","","","","","","","","","Water Management","Sanitary Engineering","","",""
"uuid:a82b630c-95e0-4a7b-8f2b-c0b2b295fe4f","http://resolver.tudelft.nl/uuid:a82b630c-95e0-4a7b-8f2b-c0b2b295fe4f","The Need to Include a Fluorine Mass Balance in the Development of Effective Technologies for PFAS Destruction","Smith, S.J. (TU Delft Sanitary Engineering); Lauria, Mélanie (Stockholm University); Higgins, Christopher P. (Colorado School of Mines); Pennell, Kurt D. (Brown University); Blotevogel, Jens (The Commonwealth Scientific and Industrial Research Organisation (CSIRO)); Arp, Hans Peter H. (Norwegian Geotechnical Institute; Norwegian University of Science and Technology (NTNU))","","2024","","analytical chemistry; mineralization; PFAS; transformation","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:cf52ea5d-6ad8-48f1-8fb3-03f42fe3c3a5","http://resolver.tudelft.nl/uuid:cf52ea5d-6ad8-48f1-8fb3-03f42fe3c3a5","Self-healing of cementitious materials using sustainable cenosphere-based manufactured aggregate","Lv, Leyang (Shenzhen University); Zhang, Xiangyu (Shenzhen University); Šavija, B. (TU Delft Materials and Environment); Zhang, Mingzhong (University College London (UCL)); Han, Kaihang (Shenzhen University); Zhang, Honghzhi (Shandong University); Pei, Chun (Shenzhen University); Zhu, Jihua (Shenzhen University); Xing, Feng (Shenzhen University)","","2024","Self-healing concrete using encapsulated healing agent has shown great potential in enhancing concrete durability. However, the capsules are expensive to make and can lower the mechanical properties of concrete. In this study, a new type of manufactured aggregate that employs waste-derived fly ash cenosphere as a carrier of healing agent (SH-CS) was designed and produced. The effect of SH-CS incorporation on hydration, engineering properties and self-healing efficiency of cement mortar was systematically evaluated, with a special focus on self-healing mechanism through the analysis of the mineral composition of the healing product. The results indicate that the prepared SH-CS has good stability in and compatibility with cement mortar. The addition of SH-CS has small influence on the fresh properties of cement mortar and less negative effect on compressive strength at the hardened stage compared to the existing study. By replacing 3 wt.% of fine aggregate with SH-CS, up to 71% of the crack opening area of mortar specimens with a crack width of about 0.3 mm was self-healed after 28 days of water exposure. The self-healing behaviour of SH-CS led to a maximal 41% drop in water adsorption and contributed to the recovery of flexural strength. The healing products precipitated on the fracture surface were mainly composed of amorphous C-S-H and Calcite. It can be estimated that incorporating SH-CS in concrete would result in only a moderate (∼29%) rise in cost for C40 concrete.","Cenosphere; Encapsulated healing agent; Engineering properties; Hydration; Microstructure; Self-healing concrete","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-21","","","Materials and Environment","","",""
"uuid:e91f3142-28d1-430f-9bb3-3341542dd073","http://resolver.tudelft.nl/uuid:e91f3142-28d1-430f-9bb3-3341542dd073","Ergonomics of spatial configurations: a voxel-based modelling framework for accessibility and visibility simulations","Azadi, S. (Eindhoven University of Technology); Bai, N. (TU Delft Heritage & Architecture); Nourian, Pirouz (University of Twente)","","2024","How can we assess the ergonomic comfort of a sizeable spatial configuration such as the indoor space of a complex building or an urban landscape when we design, plan, and manage the space? Is there a fundamental difference between indoor [architectural] spatial configurations and outdoor [urban] spatial configurations with respect to ergonomics? Can we have a unified approach to the computational study of spatial ergonomics? This paper addresses these fundamental questions while providing a brief taxonomic review of the scholarly literature on these matters from a mathematical point of view, including a brief introduction to the modelling-based approaches to the computational ways of studying the fundamental effects of spatial configuration on human behaviours. Furthermore, the paper proposes a computational approach for ergonomic assessment of spatial configurations that explicitly allows for combined accessibility and visibility analyses in the built environment. The gist of this approach is the conceptualisation of spatial configurations as rasterised (voxelated) 2D manifold walkable terrains whose voxels have 3D vistas, unifying the simulations and analyses of accessibility and visibility. The paper elaborates on how such a representation of space can provide for conducting various sorts of computational queries, analyses, and simulation experiments for research in spatial ergonomics. The paper concludes with a mapping of the computational modelling approaches pertinent to the study and assessment of spatial ergonomics; and marks avenues of future research on various categories of exploratory, generative, and associative models for ex-ante and ex-post assessment of ergonomic matters at spatial scales.","spatial ergonomics; accessibility; visibility; architectural morphology; urban morphology; simulation models","en","journal article","","","","","","","","","","","Heritage & Architecture","","",""
"uuid:6e6c08cb-2258-4157-8179-1641372ac894","http://resolver.tudelft.nl/uuid:6e6c08cb-2258-4157-8179-1641372ac894","The water-soluble fraction of extracellular polymeric substances from a resource recovery demonstration plant: characterization and potential application as an adhesive","Chen, Le Min (Student TU Delft); Erol, Özlem (Universiteit Leiden); Choi, Young Hae (Universiteit Leiden); Pronk, M. (TU Delft BT/Environmental Biotechnology; Royal HaskoningDHV); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Lin, Y. (TU Delft BT/Environmental Biotechnology)","","2024","Currently, there is a growing interest in transforming wastewater treatment plants (WWTPs) into resource recovery plants. Microorganisms in aerobic granular sludge produce extracellular polymeric substances (EPS), which are considered sustainable resources to be extracted and can be used in diverse applications. Exploring applications in other high-value materials, such as adhesives, will not only enhance the valorization potential of the EPS but also promote resource recovery. This study aimed to characterize a water-soluble fraction extracted from the EPS collected at the demonstration plant in the Netherlands based on its chemical composition (amino acids, sugar, and fatty acids) and propose a proof-of-concept for its use as an adhesive. This fraction comprises a mixture of biomolecules, such as proteins (26.6 ± 0.3%), sugars (21.8 ± 0.2%), and fatty acids (0.9%). The water-soluble fraction exhibited shear strength reaching 36–51 kPa across a pH range of 2–10 without additional chemical treatment, suggesting a potential application as an adhesive. The findings from this study provide insights into the concept of resource recovery and the valorization of excess sludge at WWTPs.","","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:58938e1b-4b36-4ce1-9c63-a7fca5cbd071","http://resolver.tudelft.nl/uuid:58938e1b-4b36-4ce1-9c63-a7fca5cbd071","Partial discharge and interference discrimination in gas-insulated systems using electric and magnetic sensors","Mier Escurra, C. (TU Delft High Voltage Technology Group); Mor, A. R. (Universitat Politécnica de Valencia); Luo, T. (TU Delft High Voltage Technology Group); Vaessen, P.T.M. (TU Delft High Voltage Technology Group; Kema Labs)","","2024","The correct identification of partial discharges (PDs) is instrumental for the maintenance plan in gas-insulated systems (GIS). However, onsite PD measurements are difficult, especially in HVDC systems, where partial discharges can be confused with interference. This paper proposes a method to discern PDs from interferences based on the GIS characteristic impedance. The characteristic impedance is measured using very-high frequency electric and magnetic sensors, and it is calculated using four approaches based on the PD charge magnitude, peak value, peak-to-peak value, and frequency spectrum. The method is first tested with a PD calibrator in a matched and open-circuited GIS testbench. Then, the identification of PDs and interference is tested in a full-scale GIS, where the measurements are subjected to pulse overlapping and noise. Five types of interferences and PDs are injected into the GIS in two positions and measured in multiple mounting holes. The results show that all four approaches can precisely calculate the characteristic impedance in a matched testbench. In the full-scale GIS, these approaches show more deviation, with the peak approach being the most accurate. A practical application of the method is demonstrated using a calibrator in the full-scale GIS. The proposed method contributes to a more reliable PD monitoring system for HVDC/AC GIS and allows better maintenance planning, reducing unnecessary costs, notably for offshore substations.","Partial discharges; Interference discrimination; Gas-insulated systems; Electric sensor; Magnetic sensor","en","journal article","","","","","","","","","","","High Voltage Technology Group","","",""
"uuid:0f61aa7a-f83f-4037-b803-32f9888ee72f","http://resolver.tudelft.nl/uuid:0f61aa7a-f83f-4037-b803-32f9888ee72f","Daily schedule changes in the automated vehicle era: Uncovering the heterogeneity behind the veil of low survey commitment","Debbaghi, Fatima-Zahra (Vrije Universiteit Brussel); Kroesen, M. (TU Delft Transport and Logistics); de Vries, G. (TU Delft Organisation & Governance); Pudane, B. (TU Delft Transport and Logistics)","","2024","Automated vehicles (AVs) may transform not only our travel experience but our complete daily schedules. This study analyses the data from an interactive stated activity-travel survey using latent class cluster analysis to uncover the types and prevalence of schedule changes with AVs. The analysis reveals that the majority of respondents expected little to no changes in their schedules. Importantly however, these responses are correlated with low commitment to the survey, evident in unrealistically short response times to non-central survey parts and simpler representations of their current schedules. The remaining responses reveal significant and varied changes in activities on board and outside travel, and in commute departure times. We conclude that the prevalence of schedule changes may be underestimated in our and possibly other AV studies due to low survey commitment. Our findings also highlight diverse potential motivations behind schedule changes with AVs: while some travellers may desire to free up time for other activities during the day (time saving), others may satisfy an unmet activity need by engaging in on-board activities (time spending). Considering this heterogeneity is crucial in endeavours to quantify the total benefits and costs that automated vehicles will bring to their users.","Automated vehicles; Time use; Activity schedules; On-board activities; Latent class clustering","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-05","","","Transport and Logistics","","",""
"uuid:259ae4f1-f642-43cc-854f-5c99dd237315","http://resolver.tudelft.nl/uuid:259ae4f1-f642-43cc-854f-5c99dd237315","Contingency Games for Multi-Agent Interaction","Peters, L. (TU Delft Learning & Autonomous Control); Bajcsy, Andrea (Carnegie Mellon University); Chiu, Chih Yuan (University of California Berkeley); Fridovich-Keil, David (The University of Texas at Austin); Laine, Forrest (VanderBilt University); Ferranti, L. (TU Delft Learning & Autonomous Control); Alonso-Mora, J. (TU Delft Learning & Autonomous Control)","","2024","Contingency planning, wherein an agent generates a set of possible plans conditioned on the outcome of an uncertain event, is an increasingly popular way for robots to act under uncertainty. In this work we take a game-theoretic perspective on contingency planning, tailored to multi-agent scenarios in which a robot's actions impact the decisions of other agents and vice versa. The resulting contingency game allows the robot to efficiently interact with other agents by generating strategic motion plans conditioned on multiple possible intents for other actors in the scene. Contingency games are parameterized via a scalar variable which represents a future time when intent uncertainty will be resolved. By estimating this parameter online, we construct a game-theoretic motion planner that adapts to changing beliefs while anticipating future certainty. We show that existing variants of game-theoretic planning under uncertainty are readily obtained as special cases of contingency games. Through a series of simulated autonomous driving scenarios, we demonstrate that contingency games close the gap between certainty-equivalent games that commit to a single hypothesis and non-contingent multi-hypothesis games that do not account for future uncertainty reduction.","Contingency management; Games; Human-Aware Motion Planning; Motion and Path Planning; Pedestrians; Planning; Planning under Uncertainty; Robots; Trajectory; Uncertainty","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-16","","","Learning & Autonomous Control","","",""
"uuid:e7aa213f-4a07-4c77-a8a7-cadbed12aca9","http://resolver.tudelft.nl/uuid:e7aa213f-4a07-4c77-a8a7-cadbed12aca9","Condition-Based Maintenance scheduling of an aircraft fleet under partial observability: A Deep Reinforcement Learning approach","Tseremoglou, I. (TU Delft Air Transport & Operations); Santos, Bruno F. (TU Delft Air Transport & Operations)","","2024","In the Condition-Based Maintenance (CBM) context, the definition of optimal maintenance plans for an aircraft fleet depends on an efficient integration of : (i) the probabilistic predictions of the health condition of the components and (ii) the stochastic arrival of the corrective maintenance tasks, together with consideration of the preventive maintenance tasks as defined in the Maintenance Planning Document (MPD). To this end, in this paper, we present a two-stage dynamic scheduling framework to solve the aircraft fleet maintenance scheduling problem under a CBM strategy in a disruptive environment. In the first stage of the framework, we address the uncertainty in the predicted health state of the monitored components by planning the optimal maintenance policy based upon the belief state-space of the health of the components. The decision-making process is formulated as a Partially Observable Markov Decision Process (POMDP) and is solved using the Partially Observable Monte Carlo Planning (POMCP) algorithm, considering the aircraft maintenance scheduling problem requirements. In the second stage, a Deep Q-Network (DQN) is developed, that integrates the defined maintenance policy of the monitored components within the scheduling of the aircraft fleet's preventive and corrective maintenance tasks. Our model, through a rolling horizon approach, continuously creates and adjusts the maintenance schedule, reacting to new updated task information, where the availability of maintenance resources constraints the execution of each task. The proposed framework was tested on a case study from a large airline and the performance was evaluated against the current state practice of the airline. The results show that our model can schedule 96.4% of monitored components on-time. As a consequence of this, a 46.2% maintenance cost reduction is achieved for the considered monitored components relative to a corrective maintenance approach.","(POMDP); Condition-Based Maintenance (CBM); Deep Reinforcement Learning; Partially Observable Markov Decision Process; Partially Observable Monte–Carlo Planning (POMCP); Planning under uncertainty; Prognostics","en","journal article","","","","","","","","","","","Air Transport & Operations","","",""
"uuid:50c053b7-70c4-4ed5-b4f1-c3d10849983a","http://resolver.tudelft.nl/uuid:50c053b7-70c4-4ed5-b4f1-c3d10849983a","Adaptation of the Recreovía During COVID-19 Lockdowns: Making Physical Activity Accessible to Older Adults in Bogotá, Colombia","González, Silvia A. (Universidad de Los Andes; District Institute of Recreation and Sports, Bogotá, Colombia); Adlakha, D. (TU Delft Urban Studies); Cabas, Santiago (Universidad de Los Andes); Sánchez-Franco, Sharon C. (Universidad de Los Andes); Rubio, Maria A. (Universidad de Los Andes); Ossa, Natalia (Universidad de Los Andes); Martínez, Paola A. (Universidad de Los Andes; LOGYCA); Espinosa, Nathally (Universidad de Los Andes); Sarmiento, Olga L. (Universidad de Los Andes)","","2024","The community restrictions during the coronavirus disease 2019 pandemic adversely impacted older adults’ physical activity levels. This convergent mixed-method study assessed the adaptation of the Recreovía, a community-based physical activity program in Bogotá, and characterized physical activity levels among older adult participants. Our results showed how the Recreovía adapted during the pandemic to continue promoting physical activity, through indoor and outdoor strategies, including virtual physical activity sessions and safety protocols. During this time, 72%–79% of the older adults attending the adapted program were physically active. A greater proportion of park users (84.2%) and more people involved in vigorous physical activity were observed during Recreovía days. Older adults had positive experiences and perceptions of the Recreovía program related to their health and social well-being. Even though the older adults prefer being outdoors, the adapted program allowed participants to continue with their physical activity routines as much as possible during the pandemic.","community-based physical activity; COVID-19 pandemic; mix-method design; healthy aging; healthy ageing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-26","","","Urban Studies","","",""
"uuid:606a9222-0b59-4b6a-8c84-64e808477a1d","http://resolver.tudelft.nl/uuid:606a9222-0b59-4b6a-8c84-64e808477a1d","Effect of the number of Cyperus rotundus and medium height on the performance of batch-constructed wetland in treating aquaculture effluent","Imron, M.F. (TU Delft Sanitary Engineering; Airlangga University); Hestianingsi, Wa Ode Ayu (Airlangga University); Putranto, Trisnadi Widyaleksono Catur (Airlangga University); Citrasari, Nita (Airlangga University); Abdullah, Siti Rozaimah Sheikh (Universiti Kebangsaan Malaysia); Hasan, Hassimi Abu (Universiti Kebangsaan Malaysia); Kurniawan, Setyo Budi (Institute of Microbiology of the Academy of Sciences of the Czech Republic)","","2024","Increasing aquaculture cultivation produces large quantities of wastewater. If not handled properly, it can have negative impacts on the environment. Constructed wetlands (CWs) are one of the phytoremediation methods that can be applied to treat aquaculture effluent. This research was aimed at determining the performance of Cyperus rotundus in removing COD, BOD, TSS, turbidity, ammonia, nitrate, nitrite, and phosphate from the batch CW system. Treatment was carried out for 30 days with variations in the number of plants (10, 15, and 20) and variations in media height (10, 12, and 14 cm). The result showed that aquaculture effluent contains high levels of organic compounds and nutrients, and C. rotundus can grow and thrive in 100% of aquaculture effluent. Besides that, the use of C. rotundus in CWs with the effect of numbers of plants and media height showed performance of COD, BOD, TSS, turbidity, ammonia, nitrate, nitrite, and phosphate with 70, 79, 90, 96, 64, 82, 92, and 48% of removal efficacy, respectively. There was no negative impact observed on C. rotundus growth after exposure to aquaculture effluent, as indicated by the increase in wet weight, dry weight, and growth rate when compared to the control. Thus, adding aquaculture effluent to CWs planted with C. rotundus supports the growth and development of plants while also performing phytoremediation.","Aquaculture; Environmental pollution; Phytotechnology; Sustainable treatment","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-02","","","Sanitary Engineering","","",""
"uuid:abbee81c-8047-420c-9684-3b666ee5dd48","http://resolver.tudelft.nl/uuid:abbee81c-8047-420c-9684-3b666ee5dd48","Fracture Mechanics: An Engineering Primer","Janssen, M. (TU Delft Team Vera Popovich); Zuidema, J; Wanhill, R.J.H. (Royal Netherlands Aerospace Centre NLR)","","2024","In this second edition, which is the result of numerous revisions, updates and additions, the authors cover the basic concepts of fracture mechanics for both the linear elastic and elastic-plastic regimes. The fracture mechanics parameters K, G, J and CTOD are treated in a basic manner along with the test methods to determine critical values. The development of failure assessment based on elastic-plastic fracture mechanics is reflected in a comprehensive treatment.
Three chapters are devoted to the fracture mechanics characterisation of crack growth. Fatigue crack growth is extensively treated and attention is paid to the important topic of the initiation and growth of short fatigue cracks. Furthermore, sustained load fracture and dynamic crack growth are discussed, including various test techniques, e.g. the determination of the crack arrest toughness.
Finally, there are two chapters dealing with mechanisms of fracture and the ways in which actual material behaviour influences the fracture mechanics characterisation of crack growth. This textbook is intended primarily for engineering students. It will be useful to practising engineers as well, since it provides the background to several test and design methods and to criteria for material selection.","Fracture Mechanisms; Fracture Toughness; Failure Assessment; Fatigue; Sustained Load Fracture","en","book","TU Delft OPEN","978-94-6366-817-0","","","","TU Delft OPEN Textbook","","","","","Team Vera Popovich","","",""
"uuid:7c702c97-ce75-4226-a15d-1b96f6da087c","http://resolver.tudelft.nl/uuid:7c702c97-ce75-4226-a15d-1b96f6da087c","Beyond control over data: Conceptualizing data sovereignty from a social contract perspective","Abbas, A.E. (TU Delft Information and Communication Technology); van Velzen, Thomas (Student TU Delft); Ofe, H.A. (TU Delft Information and Communication Technology); van de Kaa, G. (TU Delft Economics of Technology and Innovation); Zuiderwijk-van Eijk, A.M.G. (TU Delft Information and Communication Technology); de Reuver, Mark (TU Delft Information and Communication Technology)","","2024","In the data economy, data sovereignty is often conceptualized as data providers’ ability to control their shared data. While control is essential, the current literature overlooks how this facet interrelates with other sovereignty facets and contextual conditions. Drawing from social contract theory and insights from 31 expert interviews, we propose a data sovereignty conceptual framework encompassing protection, participation, and provision facets. The protection facets establish data sharing foundations by emphasizing baseline rights, such as data ownership. Building on this foundation, the participation facet, through responsibility divisions, steers the provision facets. Provision comprises facets such as control, security, and compliance mechanisms, thus ensuring that foundational rights are preserved during and after data sharing. Contextual conditions (data type, organizational size, and business data sharing setting) determine the level of difficulty in realizing sovereignty facets. For instance, if personal data is shared, privacy becomes a relevant protection facet, leading to challenges of ownership between data providers and data subjects, compliance demands, and control enforcement. Our novel conceptualization paves the way for coherent and comprehensive theory development concerning data sovereignty as a complex, multi-faceted construct.","Data economy; Data marketplaces; Data sharing; Data sovereignty; L86; Meta-platforms","en","journal article","","","","","","","","","","","Information and Communication Technology","","",""
"uuid:e56b944e-f24d-4893-81b6-4dd8304fe9aa","http://resolver.tudelft.nl/uuid:e56b944e-f24d-4893-81b6-4dd8304fe9aa","Full nitrogen and phosphorus removal in the PASDEBPR system","Kamath, P. (IHE Delft Institute for Water Education); Rubio-Rincón, F. J. (IHE Delft Institute for Water Education); Brdjanovic, Damir (TU Delft BT/Environmental Biotechnology; IHE Delft Institute for Water Education); Lopez-Vazquez, C. M. (IHE Delft Institute for Water Education)","","2024","Photo-activated sludge (PAS) system aims to utilize microalgae to deliver oxygen for bacterial respiration, eliminating the need for external aeration. However, research on the treatment potential of PAS systems in the removal of nutrients is limited. In this context, a research study was devised to evaluate the possibility of developing a microalgae-bacteria consortium to achieve the simultaneous removal of organic carbon, nitrogen, and phosphorus. A successful PAS system capable of removing phosphorus was established at the end of the first phase, with an effluent phosphorus (P) concentration of 1.6 mg P L−1. In the subsequent stage, during the introduction of the nitrification-denitrification process, the system lost stability and deteriorated. Interestingly the system recovered via the sparging of nitrogen gas reaching effluent concentrations of 1.22 mg P L−1 and 0.88 mg N L−1. Thus, the system was capable of removing phosphorus and nitrogen via biological means without the need for external aeration. It is hypothesized that the inhibition caused was due to the production of a gaseous compound during the nitrification/denitrification process.","Denitrification; Enhanced biological phosphorus removal; Microalgae-bacteria consortium; Nitrous oxide","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-16","","","BT/Environmental Biotechnology","","",""
"uuid:870df03c-b8a8-4544-9b76-0e7420f829f7","http://resolver.tudelft.nl/uuid:870df03c-b8a8-4544-9b76-0e7420f829f7","Advances in using municipal solid waste incineration (MSWI) bottom ash as precursor for alkali-activation materials: A critical review","Chen, B. (TU Delft Materials and Environment); Perumal, Priyadharshini (University of Oulu); Aghabeyk, F. (TU Delft Materials and Environment); Adediran, Adeolu (University of Oulu); Illikainen, Mirja (University of Oulu); Ye, G. (TU Delft Materials and Environment)","","2024","The pursuit of low-carbon binders as alternatives to Portland cement has sparked interest in developing alkali-activated materials (AAM).1 Using municipal solid waste incineration (MSWI) bottom ash as precursor for AAM has attracted increasing attention as it offers a sustainable, resource-efficient solution to mitigate the environmental impacts associated with the landfill of MSWI bottom ash. However, the varying properties of MSWI bottom ash present challenges in its wide application as AAM precursor. This review provides a comprehensive overview of advances in MSWI bottom ash-based AAM,2 with a particular focus on the relationship between the physicochemical properties of MSWI bottom ash and the engineering properties of MSWI bottom ash-based AAM. This work consolidates the most up-to-date understanding of the reaction mechanism and reaction products of MSWI bottom ash, along with the existing knowledge about mix design and microstructure formation of MSWI bottom ash-based AAM. The factors influencing the engineering properties of MSWI bottom ash-based AAM are detailed, and the environmental impacts of MSWI bottom ash-based AAM are reviewed. Ultimately, this review provides recommendations for the standardized and effective use of MSWI bottom ash as AAM precursor.","Alkali-activated materials; Durability; Environmental impacts; Mechanical properties; Municipal solid waste incineration bottom ash; Reaction","en","review","","","","","","","","","","","Materials and Environment","","",""
"uuid:bc8e981e-2a58-440a-8715-db3999eb64d3","http://resolver.tudelft.nl/uuid:bc8e981e-2a58-440a-8715-db3999eb64d3","Mode substitution induced by electric mobility hubs: Results from Amsterdam","Liao, F. (Radboud Universiteit Nijmegen); Vleugel, J (TU Delft Transport and Planning); Bösehans, Gustav (Newcastle University); Dissanayake, Dilum (University of Birmingham); Thorpe, Neil (Jacobs); Bell, Margaret (Newcastle University); van Arem, B. (TU Delft Transport and Planning); Correia, Gonçalo (TU Delft Transport and Planning)","","2024","Electric mobility hubs (eHUBS) are locations where multiple shared electric modes including electric cars and e-bikes are available. To assess their potential to reduce private car use, it is important to investigate to what extent people would switch to eHUBS modes after their introduction. Moreover, people may adapt their behaviour differently depending on their current travel mode. This study is based on stated preference data collected in Amsterdam. We analysed the data using mixed logit models. We found that users of different modes not only have varied general preferences for different shared modes but also have different sensitivity for attributes such as travel time and cost. Public transport users are more likely to switch to eHUBS modes than car users. People who bike and walk have strong inertia, but the percentage choosing eHUBS modes doubles when the trip distance is longer (5 or 10 km).","Carsharing; eHUBS; Mode choice; Shared e-bike","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:bc088cea-5a70-459f-8eb9-e5e6d086379b","http://resolver.tudelft.nl/uuid:bc088cea-5a70-459f-8eb9-e5e6d086379b","Towards sustainable groundwater development with effective measures under future climate change in Beijing Plain, China","Liu, S. (TU Delft Water Resources; IHE Delft Institute for Water Education); Zhou, Yangxiao (IHE Delft Institute for Water Education; Hebei University); Eiman, Fatima (IHE Delft Institute for Water Education); McClain, M.E. (TU Delft Water Resources; IHE Delft Institute for Water Education); Wang, Xu sheng (China University of Geosciences)","","2024","To cope with the groundwater depletion problem and achieve sustainable groundwater development, groundwater conservation measures and managed aquifer recharge (MAR) have been implemented worldwide. However, knowledge gaps exit how does the aquifer system respond to these interventions differently and if these interventions are adequate to lead to long-term sustainable groundwater development under future climate change. In Beijing Plain, two measures have been implemented: reduction of groundwater abstraction by substituting groundwater abstraction with transferred surface water and implementation of managed aquifer recharge (MAR) in two major rivers. This study aims to assess how do the shallow and deep aquifers respond to these measures and if these measures can lead to long-term sustainable groundwater development in Beijing Plain under future climate change. A 3-D transient groundwater flow model was calibrated and used to simulate groundwater level and budget changes from 2021 to 2050. The monthly groundwater recharge was estimated using the projected monthly precipitation from three downscaled regional climate models under two scenarios (RCP4.5 and RCP8.5). The results show that declines in groundwater head and storage can be reversed with the combined two measures, thereby contributing to achieve sustainable groundwater development. The reduction of abstractions is a deciding measure to reverse the trend of groundwater depletion, especially in the deep confined aquifers, while large scale MAR schemes can restore the cones of depressions in shallow aquifers and maintain the groundwater abstraction. Climate variation has large impacts on groundwater resources, especially, consecutive dry years can cause rapid groundwater storage depletion. The projected monthly precipitation from 2021 to 2050 is not significantly different from the past. Therefore, the projected future precipitation has minor impacts on groundwater resources in the next 30 years. The findings from the study will support the Beijing municipality to maintain the tight control on groundwater abstraction and to implement large-scale MAR schemes in two rivers. This successful example will encourage managers of other heavily exploited aquifers to take similar measures to achieve sustainable groundwater development.","Beijing Plain; Climate change; Groundwater sustainability; Substitution of abstraction, Managed Aquifer Recharge","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:1f4ed1e0-15a9-4854-a6a0-74adaa8a1424","http://resolver.tudelft.nl/uuid:1f4ed1e0-15a9-4854-a6a0-74adaa8a1424","Flocculation characteristics of suspended Mississippi River mud under variable turbulence, water and salt sources, and salinity: a laboratory study","Abolfazli, Ehsan (Virginia Tech College of Engineering); Osborn, Ryan (Virginia Tech College of Engineering); Dunne, K.B.J. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Nittrouer, Jeffrey A. (Texas Tech University); Strom, Kyle (Virginia Tech College of Engineering)","","2024","Muddy sediment constitutes a major fraction of the suspended sediment mass carried by the Mississippi River. Thus, adequate knowledge of the transport dynamics of suspended mud in this region is critical in devising efficient management plans for coastal Louisiana. We conducted laboratory tank experiments on the sediment suspended in the lower reaches of the Mississippi River to provide insight into the flocculation behavior of the mud. In particular, we measure how the floc size distribution responds to changing environmental factors of turbulent energy, sediment concentration, and changes in base water composition and salinity during summer and winter. We also compare observations from the tank experiments to in situ observations. Turbulence shear rate, a measure of river hydrodynamic energy, was found to be the most influential factor in determining mud floc size. All flocs produced at a given shear rate could be kept in suspension down to shear rates of approximately 20 s−1. At this shear rate, flocs on the order of 150–200 μm and larger can settle out. Equilibrium floc size was not found to depend on sediment concentration; flocs larger than 100 μm formed in sediment concentrations as low as 20 mgL−1. An increase in salinity generated by adding salts to river water suspensions did not increase the flocculation rate or equilibrium size. However, the addition of water collected from the Gulf of Mexico to river-water suspensions did enhance the flocculation rate and the equilibrium sizes. We speculate that the effects of Gulf of Mexico water originate from its biomatter content rather than its ion composition. Floc sizes in the mixing tanks were comparable to those from the field for similar estimated turbulent energy. Flocs were found to break within minutes under increased turbulence but can take hours to grow under conditions of reduced shear in freshwater settings. Growth was faster with the addition of Gulf of Mexico water. Overall, the experiments provide information on how suspended mud in the lower reaches of the Mississippi might respond to changes in turbulence and salinity moving from the fluvial to marine setting through natural distributary channels or man-made diversions.","flocculation; Gulf of Mexico; Mississippi River; mud; sediment","en","journal article","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:08df48eb-44d1-4ed2-b8c2-8e1fae6fc6f5","http://resolver.tudelft.nl/uuid:08df48eb-44d1-4ed2-b8c2-8e1fae6fc6f5","Investigation of mode-II delamination fracture energy with a discontinuous computational homogenization model","Ke, L. (TU Delft Applied Mechanics); van der Meer, F.P. (TU Delft Applied Mechanics)","","2024","Numerical methods for delamination analysis, such as the cohesive zone method, require fracture energy as an essential input. Existing formulations rely on a phenomenological relationship that links fracture energy to the mode of fracture based on linear elastic fracture mechanics (LEFM). However, doubts exist about the applicability of LEFM. It has been demonstrated that the phenomenological relationships describing fracture energy as a function of mode-ratio are not universally valid. Computational homogenization (FE2) provides an alternative where the dissipative mechanisms can be resolved on the microscale. This paper aims to assess the suitability of a proposed discontinuous FE2 framework for characterizing delamination growth under mode-II conditions by comparing it to direct numerical simulations (DNS). The impact of plasticity on effective fracture energy is evaluated for two distinct mode-II test configurations. The dissipation density from the bulk integration points within the delamination propagation zone is monitored. The findings demonstrate the FE2 model's capability to accurately capture plastic energy dissipation around a growing crack. Variations in plastic dissipation are observed between the mTCT and ENF test setups, leading to differences in effective mode-II fracture energy. These nuances, unaccounted for in state-of-the-art mesoscale cohesive models, highlight the FE2 framework's potential for enhancing delamination modeling.","Composites; Computational homogenization; Delamination; Fracture energy; Plasticity","en","journal article","","","","","","","","","","","Applied Mechanics","","",""
"uuid:39d9f3f8-3ac0-4654-ab33-000bf6635f9c","http://resolver.tudelft.nl/uuid:39d9f3f8-3ac0-4654-ab33-000bf6635f9c","Development of an Innovative Extension for Fatigue Life Monitoring Using a Piezoelectric Sensor","Ghaderiaram, A. (TU Delft Materials and Environment); Mohammadi, R. (TU Delft Structural Integrity & Composites); Schlangen, E. (TU Delft Materials and Environment); Fotouhi, M. (TU Delft Materials and Environment)","","2024","Engineering structures, such as bridges, wind turbines, airplanes, ships, buildings, and offshore platforms, often experience uncertain dynamic loadings due to environmental factors and operational conditions. The lack of knowledge about the load spectrum for these structures poses challenges in terms of design and can lead to either over-engineering or catastrophic failure. This research introduces a robust and innovative device, analogous to a ""Fitbit"" for structures, capable of measuring complex loading conditions throughout the structure's lifespan. The proposed approach involves developing a middleware, referred to as an ""extension,"" which facilitates the transfer of mechanical deformation to a piezoelectric sensor. This approach overcomes challenges associated with directly attaching piezoelectric sensors to the structure's surface such as rupture possibility in higher strain and attaching on rough surfaces. The feasibility study primarily focuses on validating the performance of the extension and monitoring variation trends. The ultimate objective is to develop an Internet of Things (IoT) sensor node capable of measuring applied cyclic loads. To achieve this goal, an electronic system and embedded software will be developed to capture the complex load spectrum and convert it into a fatigue damage index for predicting the structure's fatigue life. The collected data will be transmitted to the user through a wireless communication platform. The proposed sensor design is versatile, allowing for both attachment and embedding and is demonstrated here for monitoring fatigue in engineering structures.","Fatigue life monitoring; Piezoelectric sensor","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:4dee4bae-d221-4397-b589-495a74720c0f","http://resolver.tudelft.nl/uuid:4dee4bae-d221-4397-b589-495a74720c0f","Scaling up dynamic charging infrastructure: Significant battery cost savings","Liao, X. (TU Delft Transport and Planning); Saeednia, M. (TU Delft Transport and Planning); Nogal Macho, M. (TU Delft Integral Design & Management); Tavasszy, Lorant (TU Delft Transport and Planning; TU Delft Transport and Logistics)","","2024","Large-scale electrification of heavy-duty road freight faces challenges including scarcity of charging infrastructure and high battery costs. Dynamic charging could help overcome these challenges by enabling trucks to charge while driving. Important additional benefits for carriers related to lower required sizes and longer lifetimes of batteries could justify the required investments. The study investigates the optimal configuration of network sections to be electrified so that the balance between costs and benefits turns out positive. A case study for a highway network spanning 4 countries in Europe suggests that dynamic charging can lead to a significant reduction in overall transport system costs, up to very large network sizes. The study supports the decision-making of policymakers and road authorities by providing new insights into the costs and benefits of dynamic charging networks, and simultaneously considering the perspectives of investors and users.","Battery-electric landscape; Dynamic charging network planning; Sustainable road freight; Truck electrification","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:12a11b1c-a3de-4c8b-a05a-fc6790d538a5","http://resolver.tudelft.nl/uuid:12a11b1c-a3de-4c8b-a05a-fc6790d538a5","A conceptual design of two-stream alkali-activated materials","Sun, Yubo (Universiteit Gent); Mohan, Manu K. (Universiteit Gent); Tao, Yaxin (Universiteit Gent); Zhang, Yi (Universiteit Gent; Tongji University); Van Tittelboom, Kim (Universiteit Gent); Ye, G. (TU Delft Materials and Environment; Universiteit Gent); De Schutter, Geert (Universiteit Gent)","","2024","To properly control the reaction kinetics and fresh properties evolution in conventional alkali-activated materials (AAMs), a conceptual design of two-stream AAMs has been proposed in this study. This is achieved by dividing the solid and liquid components in AAMs, including blast furnace slag (BFS) and electric arc furnace slag (EFS) precursors, as well as aqueous sodium hydroxide and silicate activators into two separate streams A and B, where a very limited reactivity is expected in individual streams to ensure sufficient workability retention. Moreover, a final-stage intermixing is required to combine individual stream mixtures and trigger the major activation reaction. Fresh and hardened properties of combined mixtures were checked at different stages. The microstructure and reaction products were investigated to understand the strength development. Low dynamic rheological parameters and good workability retention have been detected in all individual stream mixtures, accompanied by limited exothermic heat flows after the initial dissolution confirmed by calorimetry tests. Further, Portland cement (PC) is partially blended into stream A to alter the early stiffening process in combined mixtures and meet various setting demands after intermixing. However, this might lead to a reduction in mechanical properties, associated with the formation of porous microstructures and an increase in the Ca/Si ratio in reaction products. Eventually, the conceptual design is validated in different scenarios including self-compacting and 3D-printing concrete applications.","3D-printing; Microstructure; Rheology; Self-compacting; Two-stream AAMs","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-23","","","Materials and Environment","","",""
"uuid:10589431-fb03-40dd-94a3-0f85d7741a09","http://resolver.tudelft.nl/uuid:10589431-fb03-40dd-94a3-0f85d7741a09","Spatial Parameters for Circular Construction Hubs: Location Criteria for a Circular Built Environment","Tsui, T.P.Y. (TU Delft Environmental & Climate Design); Furlan, C. (TU Delft Environmental Technology and Design; University of Natural Resources and Applied Life Sciences, Vienna; Universiteit Antwerpen); Wandl, Alex (TU Delft Environmental Technology and Design); van Timmeren, A. (TU Delft Environmental Technology and Design)","","2024","Implementing a circular economy in cities has been proposed by policy makers as a potential solution for achieving sustainability in the construction sector. One strategy that has gained interest by both policy makers and companies is to develop “circular construction hubs”: locations that collect, store, and redistribute waste as secondary resources. However, there is limited literature taking a spatially explicit view, identifying the spatial parameters that could affect the locations of hubs both for now and in the future. This study therefore aims to categorize different types of circular hubs for the construction industry, collect spatial parameters required for finding suitable locations for each type of circular hub, and translate the spatial parameters into a list of data and spatial analysis methods that could be used to identify potential future locations. The study used the Netherlands as a case study, extracting spatial parameters from two sources: Dutch governmental policy documents on circular economy and spatial development and interviews with companies operating circular hubs. Four types of circular construction hubs were identified: urban mining hubs, industry hubs, local material banks, and craft centers. The spatial parameters were extracted for each type of hub from four perspectives: resources (such as material type, business model), accessibility (such as mode and scale of transportation), land use (such as plot size, land use), and socio-economic (such as labor availability). The parameters were then translated into a list of spatial data and analysis methods required to identify future locations of circular construction hubs.","Circular cities; Circular construction hub; GIS; Territorializing circular economy; Urban mining; Site selection analysis","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:ba50ad21-1940-4127-a4f7-4d68b1d4ff6a","http://resolver.tudelft.nl/uuid:ba50ad21-1940-4127-a4f7-4d68b1d4ff6a","Mapping a 50-spin-qubit network through correlated sensing","van de Stolpe, G.L. (TU Delft QID/Taminiau Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kwiatkowski, D.P. (TU Delft QID/Taminiau Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bradley, C.E. (TU Delft QID/Taminiau Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Randall, J.A.D. (TU Delft QID/Taminiau Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Abobeih, M.H.M.A. (TU Delft QID/Taminiau Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Breitweiser, S. A. (University of Pennsylvania); Bassett, L. C. (University of Pennsylvania); Markham, M. (Element Six Innovation); Twitchen, D. J. (Element Six Innovation); Taminiau, T.H. (TU Delft QID/Taminiau Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2024","Spins associated to optically accessible solid-state defects have emerged as a versatile platform for exploring quantum simulation, quantum sensing and quantum communication. Pioneering experiments have shown the sensing, imaging, and control of multiple nuclear spins surrounding a single electron spin defect. However, the accessible size of these spin networks has been constrained by the spectral resolution of current methods. Here, we map a network of 50 coupled spins through high-resolution correlated sensing schemes, using a single nitrogen-vacancy center in diamond. We develop concatenated double-resonance sequences that identify spin-chains through the network. These chains reveal the characteristic spin frequencies and their interconnections with high spectral resolution, and can be fused together to map out the network. Our results provide new opportunities for quantum simulations by increasing the number of available spin qubits. Additionally, our methods might find applications in nano-scale imaging of complex spin systems external to the host crystal.","","en","journal article","","","","","","","","","","","QID/Taminiau Lab","","",""
"uuid:72083644-74c4-49fd-8314-0f7e6ecf5de0","http://resolver.tudelft.nl/uuid:72083644-74c4-49fd-8314-0f7e6ecf5de0","A computational framework for pharmaco-mechanical interactions in arterial walls using parallel monolithic domain decomposition methods","Balzani, Daniel (Center for Interface-Dominated High Performance Materials); Heinlein, A. (TU Delft Delft Institute of Applied Mathematics; TU Delft Numerical Analysis); Klawonn, Axel (University of Cologne); Knepper, Jascha (University of Cologne); Nurani Ramesh, Sharan (Center for Interface-Dominated High Performance Materials); Rheinbach, Oliver (University of Technology Bergakademie Freiberg); Saßmannshausen, Lea (University of Cologne); Uhlmann, Klemens (Center for Interface-Dominated High Performance Materials)","","2024","A computational framework is presented to numerically simulate the effects of antihypertensive drugs, in particular calcium channel blockers, on the mechanical response of arterial walls. A stretch-dependent smooth muscle model by Uhlmann and Balzani is modified to describe the interaction of pharmacological drugs and the inhibition of smooth muscle activation. The coupled deformation-diffusion problem is then solved using the finite element software FEDDLib and overlapping Schwarz preconditioners from the Trilinos package FROSch. These preconditioners include highly scalable parallel GDSW (generalized Dryja–Smith–Widlund) and RGDSW (reduced GDSW) preconditioners. Simulation results show the expected increase in the lumen diameter of an idealized artery due to the drug-induced reduction of smooth muscle contraction, as well as a decrease in the rate of arterial contraction in the presence of calcium channel blockers. Strong and weak parallel scalability of the resulting computational implementation are also analyzed.","calcium channel blockers; domain decomposition methods; drug transport; finite element method; GDSW coarse space; hypertension; iterative solvers; overlapping Schwarz; RGDSW coarse space; scalable preconditioners; smooth muscle cells; structural mechanics","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:2cc582aa-c13c-45b2-8769-09a68d2e1209","http://resolver.tudelft.nl/uuid:2cc582aa-c13c-45b2-8769-09a68d2e1209","Testing Stationarity and Statistical Independence of Multistatic/Polarimetric Sea-Clutter with Application to NetRAD Data","Aubry, Augusto (Università degli Studi di Napoli Federico II); Carotenuto, Vincenzo (Università degli Studi di Napoli Federico II); Maio, Antonio De (Università degli Studi di Napoli Federico II); Fioranelli, F. (TU Delft Microwave Sensing, Signals & Systems)","","2024","The design of bespoke adaptive detection schemes relying on the joint use of multistatic/polarimetric measurements requires a preliminary statistical inference on the clutter interference environment. This is of paramount importance to develop an analytic model for the received signal samples, which is mandatory for the synthesis of radar detectors. In this respect, the aim of this article is the development of suitable learning tools to study some important statistical features of the sea-clutter environment perceived at the nodes of a multistatic/polarimetric radar system. Precisely, the stationarity of the data in the slow-time domain is first assessed by resorting to generalized inner product (GIP) based statistics. Then, the possible presence of structural symmetries in the clutter covariance matrices is investigated. Finally, relationships between some statistical parameters characterizing the sea-clutter returns on the bistatic polarimetric channels are explored via specific sequential hypothesis testing. This research activity is complemented by the use of radar returns measured via the netted RADar (NetRAD), which collects simultaneously monostatic and bistatic polarimetric measurements. The results indicate that the analyzed data can be modeled as drawn from a stationary Gaussian process within the coherence time. In addition, the bistatic returns on the different polarimetric channels can be assumed statistically independent with speckle components possibly exhibiting proportional/equal covariance matrices depending on the transmit/receive polarization and bistatic geometry.","Spherically Invariant Random Process (SIRP); sea-clutter; multistatic/polarimetric radar; Generalized Inner Product (GIP); data homogeneity; covariance matrix structure; Model Order Selection (MOS); proportionality/equality of covariance matrices","en","journal article","","","","","","","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:d3cdc49f-3d2c-4b85-b8f4-0f63af6193d8","http://resolver.tudelft.nl/uuid:d3cdc49f-3d2c-4b85-b8f4-0f63af6193d8","A 72-Channel Resistive-and-Capacitive Sensor-Interface Chip With Noise-Orthogonalizing and Pad-Sharing Techniques","Feng, Xiangdong (Zhejiang University; Nanhu Brain-Computer Interface Institute); Luo, Yuxuan (Zhejiang University); Cai, Tianyi (Zhejiang University); Xuan, Yangfan (Zhejiang University); Zhang, Yunshan (Microaiot); Shen, Yili (Zhejiang University); Yang, Changgui (Zhejiang University); Xiao, Qijing (Zhejiang University); Du, S. (TU Delft Electronic Instrumentation); Zhao, Bo (Zhejiang University; Nanhu Brain-Computer Interface Institute)","","2024","The growing trend of the Internet of Things (IoT) involves trillions of sensors in various applications. An extensive array of parameters need to be gathered concurrently with high-precision, low-cost, and low-power sensor nodes, such as resistive (R) and capacitive (C) sensors. Single-chip channel fusion can be an effective solution, while it is challenging to suppress the noise and integrate massive I/O pads. However, conventional oversampling noise-shaping methods increase power consumption, which fails to meet the demand of long-term monitoring applications. In addition, existing R/C sensor-interface chips require a pair of I/O pads for each sensor, where the pad frame dominates the overall chip area in massive-channel integration. In this work, we demonstrate a 72-channel R&C sensor-interface chip for proximity-and-temperature sensing. A noise-orthogonalizing technique is proposed to eliminate the quantization noise at the signal frequencies, achieving an energy efficiency of 19.1 pJ/step/channel. Moreover, a pad-sharing technique is proposed to reduce the number of I/O pads by half, enabling 72 sensors to be read by 36 pairs of I/O pads. The chip is fabricated by 65-nm CMOS technology, and measurement results show resolutions of 286 Omega and 162 fF, respectively. The power consumption and die area are reduced to 0.74 mu text{W} /Channel and 0.038 mm2/Channel, respectively.","Low power; multichannel sensing; noise-orthogonalizing; pad-sharing; sensor interface","en","journal article","","","","","","","","2024-07-23","","","Electronic Instrumentation","","",""
"uuid:6d8dc39f-14bc-419e-b776-56328b984521","http://resolver.tudelft.nl/uuid:6d8dc39f-14bc-419e-b776-56328b984521","Design Formulas for Flat Gradient Index Lenses with Planar or Spherical Output Wavefront","Hu, Weiya (Student TU Delft); Coco Martin, C.M. (TU Delft Tera-Hertz Sensing); Cavallo, D. (TU Delft Tera-Hertz Sensing)","","2024","A semi-analytical method is presented for the design of gradient index (GRIN) flat lenses. Closed-form expressions are derived to define the refractive index distribution of the lens, for several cases: collimating lenses with on-axis feed, collimating lenses with off-axis feed, lenses converting spherical wavefronts with different wavenumbers, lenses changing the focal number of a quasi-optical system, and Fresnel zone lenses. The design equations are validated by ray-tracing simulations in inhomogeneous media, implemented by numerical solution of the Eikonal equation.","geometrical optics; gradient indexes lenses; lens antennas; optical design; ray tracing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-07","","","Tera-Hertz Sensing","","",""
"uuid:98be4917-1def-48a5-8e5d-0267997807bd","http://resolver.tudelft.nl/uuid:98be4917-1def-48a5-8e5d-0267997807bd","Understanding students’ adoption of the ChatGPT chatbot in higher education: the role of anthropomorphism, trust, design novelty and institutional policy","Polyportis, A. (TU Delft BT/Biotechnology and Society; Erasmus Universiteit Rotterdam); Pachos-Fokialis, N. (TU Delft Economics of Technology and Innovation)","","2024","The present research aims to highlight the underlying factors that drive students’ adoption of the ChatGPT chatbot in higher education. This study extends the meta-UTAUT framework by including additional exogenous factors of anthropomorphism, trust, design novelty, and institutional policy. Empirical examination with Structural Equation Modelling among 355 students in Dutch higher education institutions revealed attitude and behavioural intention as significant positive predictors of students’ ChatGPT use behaviour. Institutional policy negatively moderated the effect of behavioural intention on use behaviour. Behavioural intention was significantly and positively influenced by attitude, performance expectancy, social influence, and facilitating conditions. Anthropomorphism, design novelty, trust, performance expectancy, and effort expectancy were unveiled as significant positive antecedents of attitude. The central theoretical contributions of this research include investigating students’ use behaviour instead of behavioural intention, establishing attitude as a core construct, underlining additional antecedents of attitude, and highlighting the importance of institutional policy. The present study contributes to prior research on technology adoption, especially in the area of artificial intelligence in education. The findings yield valuable insights for chatbot designers, product managers, and higher education policy writers.","Anthropomorphism; chatbot adoption; ChatGPT; design novelty; higher education; meta-UTAUT","en","journal article","","","","","","","","","","","BT/Biotechnology and Society","","",""
"uuid:fd7539a7-9015-4357-8060-3cea3816205d","http://resolver.tudelft.nl/uuid:fd7539a7-9015-4357-8060-3cea3816205d","Unifying the Conversation: Membrane Separation Performance in Energy, Water, and Industrial Applications","Dischinger, Sarah M. (Lawrence Berkeley National Laboratory); Miller, Daniel J. (Lawrence Berkeley National Laboratory); Vermaas, D.A. (TU Delft ChemE/Transport Phenomena); Kingsbury, Ryan S. (Lawrence Berkeley National Laboratory; Princeton University)","","2024","Dense polymer membranes enable a diverse range of separations and clean energy technologies, including gas separation, water treatment, and renewable fuel production or conversion. The transport of small molecular and ionic solutes in the majority of these membranes is described by the same solution-diffusion mechanism, yet a comparison of membrane separation performance across applications is rare. A better understanding of how structure-property relationships and driving forces compare among applications would drive innovation in membrane development by identifying opportunities for cross-disciplinary knowledge transfer. Here, we aim to inspire such cross-pollination by evaluating the selectivity and electrochemical driving forces for 29 separations across nine different applications using a common framework grounded in the physicochemical characteristics of the permeating and rejected solutes. Our analysis shows that highly selective membranes usually exhibit high solute rejection, rather than fast solute permeation, and often exploit contrasts in the size and charge of solutes rather than a nonelectrostatic chemical property, polarizability. We also highlight the power of selective driving forces (e.g., the fact that applied electric potential acts on charged solutes but not on neutral ones) to enable effective separation processes, even when the membrane itself has poor selectivity. We conclude by proposing several research opportunities that are likely to impact multiple areas of membrane science. The high-level perspective of membrane separation across fields presented herein aims to promote cross-pollination and innovation by enabling comparisons of solute transport and driving forces among membrane separation applications.","Chemical potential; Membranes; Permeability; Selectivity; Separation mechanism","en","review","","","","","","","","","","","ChemE/Transport Phenomena","","",""
"uuid:efd0081a-9890-40e4-a444-392190c28f7b","http://resolver.tudelft.nl/uuid:efd0081a-9890-40e4-a444-392190c28f7b","Do You Need a Hand?: a Bimanual Robotic Dressing Assistance Scheme","Zhu, J. (TU Delft Learning & Autonomous Control; University of York); Gienger, Michael (Honda Research Institute Europe GmbH); Franzese, G. (TU Delft Learning & Autonomous Control); Kober, J. (TU Delft Learning & Autonomous Control)","","2024","Developing physically assistive robots capable of dressing assistance has the potential to significantly improve the lives of the elderly and disabled population. However, most robotics dressing strategies considered a single robot only, which greatly limited the performance of the dressing assistance. In fact, healthcare professionals perform the task bimanually. Inspired by them, we propose a bimanual cooperative scheme for robotic dressing assistance. In the scheme, an interactive robot joins hands with the human thus supporting/guiding the human in the dressing process while the dressing robot performs the dressing task. We identify a key feature: the elbow angle that affects the dressing action and propose an optimal strategy for the interactive robot using the feature. A dressing coordinate based on the posture of the arm is defined to better encode the dressing policy. We validate the interactive dressing scheme with extensive experiments and also an ablation study.","Estimation; Manipulators; Robot kinematics; Robots; Sensors; Task analysis; Tracking","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-14","","","Learning & Autonomous Control","","",""
"uuid:1c3889b2-579d-4f23-86c2-33e896c28867","http://resolver.tudelft.nl/uuid:1c3889b2-579d-4f23-86c2-33e896c28867","Tunable Quantum Criticality in Multicomponent Rydberg Arrays","Chepiga, N. (TU Delft QN/Chepiga Lab; Kavli institute of nanoscience Delft)","","2024","Arrays of Rydberg atoms have appeared as a remarkably rich playground to study quantum phase transitions in one dimension. One of the biggest puzzles that was brought forward in this context are chiral phase transitions out of density waves. Theoretically predicted chiral transition out of period-four phase is still pending experimental verification mainly due to extremely short interval over which this transition is realized in a single-component Rydberg array. In this Letter, we show that multicomponent Rydberg arrays with extra experimentally tunable parameters provide a mechanism to manipulate quantum critical properties without breaking translation symmetry explicitly. We consider an effective blockade model of two component Rydberg atoms. Weak and strong components obey nearest- and next-nearest-neighbor blockades correspondingly. When laser detuning is applied to either of the two components the system is in the period-3 and period-2 phases. But laser detuning applied to both components simultaneously stabilizes the period-4 phase partly bounded by the chiral transition. We show that relative ratio of the Rabi frequencies of the two components tunes the properties of the conformal Ashkin-Teller point and allows us to manipulate an extent of the chiral transition. The prospects of multicomponent Rydberg arrays in the context of critical fusion is briefly discussed.","","en","journal article","","","","","","","","","","","QN/Chepiga Lab","","",""
"uuid:468b11e4-732a-426e-9b5c-3307081177ad","http://resolver.tudelft.nl/uuid:468b11e4-732a-426e-9b5c-3307081177ad","Enhancing the durability of Pt nanoparticles for water electrolysis using ultrathin SiO2 layers","Li, M. (TU Delft ChemE/Product and Process Engineering); Saedy, S. (TU Delft ChemE/Product and Process Engineering); Fu, S. (TU Delft Large Scale Energy Storage); Stellema, T.P. (Student TU Delft); Kortlever, R. (TU Delft Large Scale Energy Storage); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering)","","2024","Extending the lifetime of electrocatalytic materials is a major challenge in electrocatalysis. Here, we employ atomic layer deposition (ALD) to coat the surface of carbon black supported platinum nanoparticles (Pt/CB) with an ultra-thin layer of silicon dioxide (SiO2) to prevent deactivation of the catalyst during H2 evolution. Our results show that after an accelerated durability test (ADT) the current density at −0.2 V vs. reversible hydrogen electrode (RHE) of the unprotected Pt/CB catalyst was reduced by 34%. By contrast, after coating the Pt/CB catalyst with 2 SiO2 ALD cycles, the current density at the same potential was reduced by 7% after the ADT procedure, whereas when the Pt/CB sample was coated with 5 SiO2 ALD cycles, the current density was reduced by only 2% after the ADT. Characterization of the Pt particles after electrochemical testing shows that the average particle size of the uncoated Pt/CB catalyst increases by roughly 16% after the ADT, whereas it only increases by 3% for the Pt/CB catalyst coated with 5 cycles of SiO2 ALD. In addition, the coating also strongly reduces the detachment of Pt nanoparticles, as shown by a strong decrease in the Pt concentration in the electrolyte after the ADT. However, 20 cycles of SiO2 ALD coating results in an over-thick coating that has an inhibitory effect on the catalytic activity. In summary, we demonstrate that only a few cycles of SiO2 ALD can strongly improve the stability of Pt catalyst for the hydrogen evolution reaction.","","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:0dea20a7-3733-4325-8ba8-6a59857f228a","http://resolver.tudelft.nl/uuid:0dea20a7-3733-4325-8ba8-6a59857f228a","Exploring beliefs and perceptions towards Advanced Rider Assistance Systems (ARAS) in motorcycle safety","Kaye, Sherrie Anne (Queensland University of Technology); Nandavar, Sonali (Queensland University of Technology); Lewis, Ioni (Queensland University of Technology); Blackman, Ross (Deakin University); Schramm, Amy; McDonald, Melinda (Queensland University of Technology); Oviedo-Trespalacios, O. (TU Delft Safety and Security Science); Haworth, Narelle (Queensland University of Technology)","","2024","The study applied the Theory of Planned Behaviour (TPB) to explore motorcycle riders’ underlying behavioural, normative, and control beliefs towards Advanced Rider Assistance Systems (ARAS). Each belief was explored in terms of three categories of technologies, (i) advanced technologies that help riders manage riding according to situations and conditions, (ii) advanced technologies that help riders to stop, and (iii) advanced technologies that help riders to corner. Eight focus groups were conducted with 39 motorcycle riders (Mage = 44.54 years, 27 males) who resided in Australia. First, participants completed a short online questionnaire which asked demographic information (e.g., age, gender, riding experience), before taking part in a 50-minute semi-structured online focus group. Participants’ knowledge of ARAS differed depending on the type of technology, with most participants reporting good to excellent knowledge of cruise control and standard anti-lock braking system (ABS) and a poor to fair understanding of selectable riding modes and cornering ABS. For behavioural beliefs, two common advantages reported for all three categories of technologies were safety and that the technologies would benefit new riders or riders with less experience. The three common disadvantages included concerns over riders’ reliance on the technologies, cost, and loss of skill or false sense of security. For normative beliefs, participants reported that their loved ones (i.e., partner, family, and friends) would approve of them using these technologies, with participants perceiving that ‘purists’ (i.e., riders who prefer to ride traditional motorcycles) would disapprove. For control beliefs, cost, lack of information on the safety of advanced technologies, and not being able to switch off systems were reported as barriers to use. Lowering insurance premiums, education/test rides, technologies as selectable options, and availability, were all identified as factors that would encourage use of ARAS. By providing information about ARAS, riders will become more informed about ARAS, which may enhance trust and user acceptance. Additionally, ongoing research and development are essential to ensure the evaluation and improvement of ARAS and mitigate any unintended consequences.","Advanced rider assistance systems; Beliefs; Motorcycle; Qualitative research; Theory of planned behaviour","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:fdf06b31-3987-4387-8420-f0d161978b5d","http://resolver.tudelft.nl/uuid:fdf06b31-3987-4387-8420-f0d161978b5d","From ethics to epistemology and back again: informativeness and epistemic injustice in explanatory medical machine learning","Pozzi, G. (TU Delft Ethics & Philosophy of Technology); Duran, J.M. (TU Delft Ethics & Philosophy of Technology)","","2024","In this paper, we discuss epistemic and ethical concerns brought about by machine learning (ML) systems implemented in medicine. We begin by fleshing out the logic underlying a common approach in the specialized literature (which we call the informativeness account). We maintain that the informativeness account limits its analysis to the impact of epistemological issues on ethical concerns without assessing the bearings that ethical features have on the epistemological evaluation of ML systems. We argue that according to this methodological approach, epistemological issues are instrumental to and autonomous of ethical considerations. This means that the informativeness account considers epistemological evaluation uninfluenced and unregulated by an ethical counterpart. Using an example that does not square well into the informativeness account, we argue for ethical assessments that have a substantial influence on the epistemological assessment of ML and that such influence should not be understood as merely informative but rather regulatory. Drawing on the case analyzed, we claim that within the theoretical framework of the informativeness approach, forms of epistemic injustice—especially epistemic objectification—remain unaddressed. Our analysis should motivate further research investigating the regulatory role that ethical elements play in the epistemology of ML.","Epistemic injustice; Epistemology and ethics of ML; Explanatory ML; Informativeness; Medical ML","en","journal article","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:1c902586-87c8-4396-8563-fa9fadf8dee1","http://resolver.tudelft.nl/uuid:1c902586-87c8-4396-8563-fa9fadf8dee1","The impact of decarbonising the iron and steel industry on European power and hydrogen systems","Boldrini, Annika (European Commission Joint Research Centre; Universiteit Utrecht); Koolen, Derck (European Commission; Universiteit Utrecht); Crijns-Graus, Wina (Universiteit Utrecht); van den Broek, M.A. (TU Delft Energie and Industrie)","","2024","The transition of the European iron and steel industry (ISI) towards low-carbon manufacturing is crucial for the European Union (EU)’s 2050 climate neutrality objective. One emerging solution is electrification by using hydrogen (H2) as iron ore reductant, which increases specific electricity use per tonne of steel up to 35 times compared to the conventional, most adopted coal-based technology. This study develops three scenarios, encompassing a moderate to an accelerated ISI transition, to evaluate the impact of the ISI decarbonisation on the power system CO2 emissions, generation mix and volume, and marginal prices in 2030. The study first estimates future electricity and H2 demand by considering country-specific technologies deployment and energy intensities. Then, these estimates serves as input to the model METIS to simulate European power system operations through a unit commitment and economic dispatch problem. The study shows that the power system can accommodate a transition of the ISI that substitutes 28% of the coal-based production with low carbon technologies, mainly based on H2. This leads to a 25% reduction in direct CO2 emissions and a demand increase of 20 TWh of electricity and 40 TWhHHV of H2. Furthermore, a 50% reduction in indirect power system emissions is achieved, compared to 2018, thanks to the substantial renewable power capacity deployment foreseen in the coming years. The study also demonstrates that a reduction of indirect CO2 emissions by over 85% can be achieved by deploying 1.2 and 2.7 GW of renewable power generators, and 200 and 400 MW of electrolyser capacity for each million tonne of steel produced annually with low-carbon technologies. Additional renewable capacity that ensures green steel production is also key to maintaining stable electricity prices.","Decarbonisation; Energy policy; Hydrogen; Iron and steel industry; Power systems","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:081986a3-7360-4815-98a2-7cedce5b224b","http://resolver.tudelft.nl/uuid:081986a3-7360-4815-98a2-7cedce5b224b","Impact of Speed Limit Enforcement Cameras on Speed Behavior: Naturalistic Evidence from Brazil","Amancio, Eduardo Cesar (Universidade Tecnológica Federal Do Paraná (UTFPR)); Gadda, Tatiana Maria Cecy (Universidade Tecnológica Federal Do Paraná (UTFPR)); Corrêa, Janine Nicolosi (Universidade Tecnológica Federal Do Paraná (UTFPR)); Bonetti, Gabriela da Costa (Universidade Tecnológica Federal Do Paraná (UTFPR)); Oviedo-Trespalacios, O. (TU Delft Safety and Security Science); Bastos, Jorge Tiago (Federal University of Paraná)","","2024","Speeding is widely recognized as a key contributor to the occurrence and severity of road crashes, making studies on speed reduction devices particularly relevant given poor road safety outcomes worldwide. This study investigates the impact of fixed speed cameras on driver behavior and speed reduction in urban arterials using a naturalistic driving study methodology. Data from 13 drivers and 116 trips in Curitiba, Brazil, were analyzed, with a focus on speed cameras placed on arterial roads. Speed data were grouped and analyzed by various categories, including topographic profile, day and week periods, and rain conditions. Mean comparisons were used to compare data sets, revealing an overall speed reduction effect of 0.69 km/h (−1.33%) around the speed camera. The study identified a pattern of punctual speed reduction, known as a “kangaroo jump,” a speed reduction followed by an increase in speed, referred to as the “compensation effect,” and a new pattern characterized by a non-significant speed reduction at the speed camera site followed by an increase in speed, referred to as the “cobra strike effect” because of its curve pattern. The largest speed reductions were observed for flat topographic profiles (−2.98%), daytime travel (−1.58%), and travel on working days (−1.75%) with rain (−1.80%). Conversely, the speed camera had little impact on vehicle speed for uphill topographic profiles, no rain conditions, and travels during weekend.","automated enforcement; general; safety; speeding; traffic law enforcement","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:fbe01343-2ef4-4134-b547-9ff1ab8f310b","http://resolver.tudelft.nl/uuid:fbe01343-2ef4-4134-b547-9ff1ab8f310b","Green ammonia supply chain and associated market structure","Zhao, H. (TU Delft Energie and Industrie)","","2024","Green ammonia is poised to be a key part in the hydrogen economy. This paper discusses green ammonia supply chains with a focus on market structures. The architecture of upstream and downstream supply chains is explored. Market structure prototypes in different stages are explored based on transaction cost economics and lessons from the energy industry. In the infancy, a highly vertically integrated structure is proposed to reduce risks and ensure capital recovery. A restructuring towards a disintegrated structure is necessary in the next stage to improve the efficiency. In the late stage, a competitive structure characterized by a separation between asset ownership and production activities and further development of short-term and spot markets are proposed towards a market-driven industry. Mixed structures combining multiple structure features are also discussed due to the dependency on actual conditions. Further, a multi-linear regression model is developed to evaluate the designed structures using a case in the gas industry, due to the commonality in vertical integration and data availability. Results indicate that high asset specificity and uncertainty and low frequency lead to a more disintegrated market structure, and vice versa, thus supporting the structures designed. In addition, evidence from the latest trends in the clean ammonia market also verifies the designed early structure. Besides, potential ways to accelerate market emergence are also discussed. We assume the findings and results contribute to developing green ammonia supply chains and the hydrogen economy.","Green ammonia; Hydrogen economy; Market structure; Supply chain; Transaction cost economics","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:6f2d7bae-5777-4e37-aa8a-875e2704e62a","http://resolver.tudelft.nl/uuid:6f2d7bae-5777-4e37-aa8a-875e2704e62a","Optimizing safety barrier allocation to prevent domino effects in large-scale chemical clusters using graph theory and optimization algorithms","Zhang, Muchen (Nanjing Tech University); Li, Zelin (Nanjing Tech University); Hou, Shuya (Nanjing Tech University); Deng, Siyu (Nanjing Tech University); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven); Yang, M. (TU Delft Safety and Security Science; Universiti Teknologi Malaysia; University of Tasmania); Zhang, Bin (Nanjing Tech University)","","2024","Domino effects are high-impact low-probability events that can have catastrophic consequences. To prevent and to reduce risks related to such events, safety barriers (SBs) are crucial. However, the initiation, propagation, and stopping processes of domino effects are characterized with complexity and uncertainties and hence they are unpredictable. This makes it challenging to allocate SBs based on predicted probabilities. In this study, a multi-objective optimization model which integrates graph theory with Non-dominated Sorting Genetic Algorithm II (NSGA-II) was proposed to allocate add-on SBs effectively. Graph metrics were used to quantify the escalation risks related to storage tanks and to optimize the allocation of add-on SBs, thereby minimizing the consequences of a domino effect under a budget constraint. The results of the case study demonstrate great efficiency in finding globally optimal strategies with a largest reduction of 94.3% in the out-closeness score due to the implementation of add-on SBs, allowing decision-makers to choose the most preferable investment strategy in face of domino effect risk. Our study therefore provides a novel approach to achieve an optimal allocation of add-on SBs globally and can be useful in preventing domino effects in large-scale chemical clusters equipped with a large number of storage tanks.","Domino effects; Graph theory; Multi-objective optimization; NSGA-II; Safety barriers","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-22","","","Safety and Security Science","","",""
"uuid:3abe64b4-8a0a-4f2a-ae47-679c9294e659","http://resolver.tudelft.nl/uuid:3abe64b4-8a0a-4f2a-ae47-679c9294e659","Are creative users more apt in reusing and adopting Open Government Data (OGD)? Gender differences","Alexopoulos, Charalampos (University of the Aegean); Saxena, Stuti (Graphic Era University); Rizun, Nina (Politechnika Gdanska); Matheus, R. (TU Delft Information and Communication Technology); Janssen, M.F.W.H.A. (TU Delft Engineering, Systems and Services)","","2024","Open Government Data (OGD) has been considered as a potent instrument for value creation and innovation by a range of stakeholders. Given that individual ingenuity is a function of individual and environmental factors, it is important to understand how the OGD adoption and usage is a factor of creative performance behaviors (CPB), viz., Problem Identification (PI), Information Search (IS), Idea Generation (IG) and Idea Promotion (IP) as well as creative self-efficacy (CSE). Invoking the adapted Unified Theory of Acceptance and Use of Technology (UTAUT) constructs alongside the moderating effects of CPB and CSE constructs and also gender, the present study seeks to underline the behavioural intention towards OGD adoption and usage among 362 undergraduate and postgraduate university students in India. The guiding research question is: “Is there any difference among the males and females in terms of their OGD adoption and usage as far as their creative propensities are concerned?” Findings from the PLS-SEM (Partial Least Squares-Structural Equation Modeling) procedures show that there are gender differences across the CPB and CSE constructs. The study's contribution lies in furthering our understanding of OGD adoption and use with the additional determinants of creativity literature.","CPB; Creative performance behavior; Creative self-efficacy; Creativity; CSE; Gender; OGD; Open government data; UTAUT","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-18","","Engineering, Systems and Services","Information and Communication Technology","","",""
"uuid:58b1acba-4b66-45ec-91a5-3b196b531ac9","http://resolver.tudelft.nl/uuid:58b1acba-4b66-45ec-91a5-3b196b531ac9","Digital Slot Machines: Social Media Platforms as Attentional Scaffolds","Voinea, Cristina (Oxford Uehiro Centre for Practical Ethics); Marin, L. (TU Delft Ethics & Philosophy of Technology); Vică, Constantin (Bucharest University)","","2024","In this paper we introduce the concept of attentional scaffolds and show the resemblance between social media platforms and slot machines, both functioning as hostile attentional scaffolds. The first section establishes the groundwork for the concept of attentional scaffolds and draws parallels to the mechanics of slot machines, to argue that social media platforms aim to capture users’ attention to maximize engagement through a system of intermittent rewards. The second section shifts focus to the interplay between emotions and attention, revealing how online attentional capture through emotionally triggering stimuli leads to distraction. The final section elucidates the collective implications of scaffolding attention through social media platforms. The examination of phenomena such as emotional contagion and the emergence of group emotions underscores the transition from individual experiences to shared collective outcomes. Employing online moral outrage as a case study, we illustrate how negative emotions serve as scaffolds for individuals’ attention, propagate within social groups, and give rise to collective attitudes.","Attentional scaffolds; Digital slot machines; Hostile scaffolds; Social media platforms","en","journal article","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:cd347b6d-0075-4742-b13b-ab21fabd50c3","http://resolver.tudelft.nl/uuid:cd347b6d-0075-4742-b13b-ab21fabd50c3","Enhanced sensitivity and tunability of thermomechanical resonance near the buckling bifurcation","Liu, Hanqing (TU Delft Dynamics of Micro and Nano Systems; National University of Defense Technology); Baglioni, G. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Boix-Constant, Carla (Universidad de Valencia (ICMol)); van der Zant, H.S.J. (TU Delft QN/van der Zant Lab); Steeneken, P.G. (TU Delft Dynamics of Micro and Nano Systems); Verbiest, G.J. (TU Delft Dynamics of Micro and Nano Systems)","","2024","The high susceptibility of ultrathin two-dimensional (2D) material resonators to force and temperature makes them ideal systems for sensing applications and exploring thermomechanical coupling. Although the dynamics of these systems at high stress has been thoroughly investigated, their behavior near the buckling transition has received less attention. Here, we demonstrate that the force sensitivity and frequency tunability of 2D material resonators are significantly enhanced near the buckling bifurcation. This bifurcation is triggered by compressive displacement that we induce via thermal expansion of the devices, while measuring their dynamics via an optomechanical technique. We understand the frequency tuning of the devices through a mechanical buckling model, which allows to extract the central deflection and boundary compressive displacement of the membrane. Surprisingly, we obtain a remarkable enhancement of up to 14× the vibration amplitude attributed to a very low stiffness of the membrane at the buckling transition, as well as a high frequency tunability by temperature of more than 4.02$\%$ K−1. The presented results provide insights into the effects of buckling on the dynamics of free-standing 2D materials and thereby open up opportunities for the realization of 2D resonant sensors with buckling-enhanced sensitivity.","nanomechanical resonator; buckling bifurcation; frequency tuning; vibration amplitude","en","journal article","","","","","","","","","","","Dynamics of Micro and Nano Systems","","",""
"uuid:af03cb84-d74a-4738-b928-3c63e31c7c92","http://resolver.tudelft.nl/uuid:af03cb84-d74a-4738-b928-3c63e31c7c92","What factors contribute to in-role and extra-role safety behavior among food delivery riders?","Nguyen-Phuoc, Duy Quy (The University of Da Nang); Mai, Nhat Xuan (The University of Da Nang); Ho-Mai, Nhi Thao (Hanken School of Economics); Nguyen, Minh Hieu (University of Transport and Communications); Oviedo-Trespalacios, O. (TU Delft Safety and Security Science)","","2024","Food delivery riders face significant road safety risks globally. Previous studies have primarily focused on the direct relationship between job demands, job resources, and road safety behaviors, often neglecting the potential indirect paths through dual processes, namely the health impairment process and the motivational process, which may lead to dangerous riding behaviors. Additionally, the impact of organizational citizenship behaviors on the safety of food delivery riders within the industry remains unexplored. This study aims to address these gaps by applying the dual processes of the Job Demands-Resources model (JD-R) to identify factors influencing the safety behaviors of food delivery riders in Vietnam. Data were collected through face-to-face surveys with 410 riders in public places. The findings show a nuanced interplay between job demands, resources, and safety behaviors. Specifically, job burnout acts as a bridge, mediating the influence of job demands on in-role safety behaviors. On the other hand, job resources-encompassing facets like job autonomy, performance feedback, technology support, and work support-indirectly shape both in-role and extra-role safety behaviors via the conduit of motivation. These resources not only bolster motivation but also serve as pillars in fostering a culture of safety among riders. This research not only deepens our understanding of the determinants of food delivery riders' safety behaviors but also highlights the pivotal role food delivery companies play in shaping these behaviors. By prioritizing the holistic well-being of their riders and offering robust support, these companies can foster an environment conducive to safety. Additionally, by integrating additional dimensions of job demands and resources into the JD-R model, this study paves the way for more comprehensive and nuanced future research in this domain.","Gig Economy workers; Human factors; Job design; Job strain; Occupational safety; Safety behaviors","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-06","","","Safety and Security Science","","",""
"uuid:76a85d9f-76a1-499c-afff-3e10802772bc","http://resolver.tudelft.nl/uuid:76a85d9f-76a1-499c-afff-3e10802772bc","Why and how often do authorities remunicipalise urban public transport? The case of France","van de Velde, Didier (TU Delft Organisation & Governance); Desmaris, Christian (Université de Lyon)","","2024","For decades, public transport services in most French towns and cities have been provided on a delegated management basis, by subcontracting to private parties, using calls for tender as a selection mechanism. Recently, however, a number of cities, some of them large, have opted for direct management, moving away from the private, competitive model in favour of public management.
Our study answers two questions: What is the scale of this shift? And how can it be interpreted: what are the triggers and motivations behind it? The literature on these questions is sparse, partial and dated. Our database shows that remunicipalisation is no longer an anecdotal phenomenon in France. Our interviews reveal that the motivations are always composite and that political factors are predominant.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-11","","","Organisation & Governance","","",""
"uuid:0d7b1285-0322-445f-aa42-98e333f041d2","http://resolver.tudelft.nl/uuid:0d7b1285-0322-445f-aa42-98e333f041d2","Architecture Unmoored","Radman, A. (TU Delft Theory, Territories & Transitions)","","2024","Review of Architecture after Deleuze and Guattari, by Chris L. Smith, London, Bloomsbury, 2023, 248 pp., ISBN: 978-1-3501-6849-7","","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-15","","","Theory, Territories & Transitions","","",""
"uuid:6f16e4ed-0bbf-4920-88c1-730d33b34331","http://resolver.tudelft.nl/uuid:6f16e4ed-0bbf-4920-88c1-730d33b34331","Circular Robotic Construction","Vasey, Lauren (ETH Zürich); Aejmelaeus-Lindström, Petrus (ETH Zürich); Jenny, David (ETH Zürich); Johns, Ryan Luke (ETH Zürich); Hurkxkens, Ilmar (TU Delft Landscape Architecture); Ming, Coralie (Boston Consulting Group Inc.); Hutter, Marco (ETH Zürich); Gramazio, Fabio (ETH Zürich); Kohler, Matthias (ETH Zürich)","De Wolf, Catherine (editor); Çetin, Sultan (editor); Bocken, Nancy (editor)","2024","In situ robotic construction is a type of construction where mobile robotic systems build directly on the building site. To enable on-site navigation, industrial robots can be integrated with mobile bases, while mobile, high-payload construction machines can be adapted for autonomous operation. With parallel advances in sensor processing, these robotic construction processes can become robust and capable of handling non-standard, local, as-found materials.
The potential of using autonomous, mobile robotic systems for the development of innovative circular construction processes is presented in three exemplary case studies:(i) robotically jammed structures from bulk materials, (ii) robotic earthworks with local and upcycled materials, and (iii) robotic additive manufacturing with earth-based materials. These processes exemplify key strategies for a circular industry through the utilisation of materials with low embodied greenhouse gas emissions and the implementation of fully reversible construction processes.
For each case study, we describe the robotic building process, the enabling technologies and workflows, and the major sustainability and circularity benefits compared to conventional construction methods. Moreover, we discuss the difficulty of industry transfer, considering challenges such as detailing, integration, and engineering validation. We conclude with an outlook towards future research avenues and industry adoption strategies.","circular robotic construction; adaptive robotic construction; in situ robotic construction; digital fabrication with natural materials","en","book chapter","Springer","","","","","","","","","","Landscape Architecture","","",""
"uuid:ae6347bb-86e3-4b0a-ab89-ecf6b8a71e30","http://resolver.tudelft.nl/uuid:ae6347bb-86e3-4b0a-ab89-ecf6b8a71e30","Towards Circular ICUs: Circular Intubations as a Catalyser for Systemic Change","Ville, Alicia (Student TU Delft); Hunfeld, Nicole (Erasmus MC); Bakker, C.A. (TU Delft Circular Product Design); Sené, Baptiste (Van Berlo); Diehl, J.C. (TU Delft Design for Sustainability)","Melles, M. (editor); Goossens, R.H. (editor)","2024","This project aims to reduce the environmental impact of the Intensive Care Unit (ICU) of the Erasmus Medical Center (EMC). Systemic design research was executed to map the current waste flow created by the ICU. Literature review, interviews and observations were performed to gather information about the healthcare protocols, hospital procurement process, intubation practices and used devices and consumables. This resulted in a set of challenges which were used to ideate from different perspectives to improve the sustainability of the ICU. A set of opportunities to introduce circularity within the ICU were defined. These opportunities ranged from waste separation to the reduction of the disposal of unused products. The selected circular opportunity was intubation, needed when patients cannot breathe by themselves. For this, a video laryngoscope, which is composed of various plastics, a video camera, and a led light, is used for only a few minutes and disposed of (and incinerated) directly afterwards. The aim of the second part of this research project was: Can we design a circular intubation procedure as a catalyzer for systemic change towards circular ICUs? One of the proposed circular strategies for the video laryngoscope is the reprocessing of intubation devices used at the ICU itself. A transition model toward reprocessing using UV-C radiation technique was further developed. Compared to current reprocessing procedures, UV-C disinfection consumes no water and less electricity and offers the possibility of decentralized reprocessing within the ICU department itself. This project aims to provoke conversations between the hospital, manufacturers and other stakeholders about how the healthcare sector could start reprocessing valuable medical devices towards a circular ICU.","Circular healthcare; Systemic design; Intensive Care Unit; Intubation","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-05","","","Circular Product Design","","",""
"uuid:cefb494c-0fd9-4579-a9b2-bedb2f671eb5","http://resolver.tudelft.nl/uuid:cefb494c-0fd9-4579-a9b2-bedb2f671eb5","Current Business Model Practices in Energy Master Planning for Regions, Cities and Districts","Haase, Matthias (Zurich University of Applied Science (ZHAW)); Konstantinou, T. (TU Delft Architectural Technology)","Bisello, Adriano (editor); Vettorato, Daniele (editor); Bottero, Marta (editor); Kolokotsa, Dionysia (editor)","2024","Roughly 97% of the European Union (EU) building stock is not considered energy efficient, and 75–85% of it will still be in use in 2050 (Artola et al., Boosting building renovation: What potential and value for Europe? 2016). Residential buildings account for around two thirds of final energy consumption in European buildings. The rate at which new buildings either replace the old stock or expand the total stock is about 1% per year. Similarly, the current renovation rate of existing buildings in the EU is about 1–2% of the building stock renovated each year. Renovation strategies on building levels need to be derived from a combination of energy efficiency upgrades to buildings and the use of renewable energy to decarbonize the energy supply, on a district or city scale. IEA EBC Annex 75 subtask D2 focuses on promoting cost-effective building renovation at district level combining energy efficiency and renewable energy systems, by focusing on the business models that can make implementation possible. This paper intends to provide an overview of the business model archetypes that can support the development of district demand and/or supply of energy-efficient building renovations and/or renewable energy solutions by targeting various types of stakeholders. It builds upon existing literature to gain insights into the current distributed energy business model landscape. Further, implementation strategies are identified that focus on a holistic evaluation of the expected energy and CO2 performance of the site and optimized infrastructure investment pathways.","Business models; Decarbonization; District scale","en","conference paper","Springer","","","","","Funding Information: The work presented in this paper was developed as a contribution to the IEA EBC Annex 75 project. The authors would like to acknowledge all project participants and all national funding organizations.","","","","","Architectural Technology","","",""
"uuid:f9723127-daa3-4674-a3c2-88c2b9a9bcf4","http://resolver.tudelft.nl/uuid:f9723127-daa3-4674-a3c2-88c2b9a9bcf4","Peering into the Darkness: The Use of UTRS in Combating DDoS Attacks","Anghel, R.I. (TU Delft Organisation & Governance); Vetrivel, Swaathi (TU Delft Organisation & Governance); Turcios Rodriguez, E.R. (TU Delft Organisation & Governance); Sameshima, Kaichi (Yokohama National University); Makita, Daisuke (Yokohama National University; National Institute of Information and Communications Technology); Yoshioka, Katsunari (Yokohama National University); Hernandez Ganan, C. (TU Delft Organisation & Governance); Zhauniarovich, Y. (TU Delft Organisation & Governance)","Tsudik, Gene (editor); Conti, Mauro (editor); Liang, Kaitai (editor); Smaragdakis, Georgios (editor)","2024","Remotely Triggered Black Hole (RTBH) is a common DDoS mitigation approach that has been in use for the last two decades. Usually, it is implemented close to the attack victim in networks sharing some type of physical connectivity. The Unwanted Traffic Removal Service (UTRS) project offers a free, global, and relatively low-effort-to-join and operate RTBH alternative by removing the requirement of physical connectivity. Given these unique value propositions of UTRS, this paper aims to understand to what extent UTRS is adopted and used to mitigate DDoS attacks. To reach this goal, we collected two DDoS datasets describing amplification and Internet-of-Things-botnet-driven attacks and correlated them with the information from the third dataset containing blackholing requests propagated to the members of UTRS. Our findings suggest that, currently, just a small portion of UTRS members (approximately 10 % ) trigger mitigation attempts: out of 1200+ UTRS members, only 124 triggered blackholing events during our study. Among those, with high probability, 25 Autonomous Systems (ASes) reacted on AmpPot attacks mitigating 0.025 % of them globally or 1.03 % targeting UTRS members; 2 countered IoT-botnet-driven attacks alleviating 0.001 % of them globally or 0.06 % targeting UTRS members. This suggests that UTRS can be a useful tool in mitigating DDoS attacks, but it is not widely used.","DDoS attacks; RTBH; UTRS","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-11","","","Organisation & Governance","","",""
"uuid:cd38f9cf-ad14-4323-ab0d-51c4feb613f9","http://resolver.tudelft.nl/uuid:cd38f9cf-ad14-4323-ab0d-51c4feb613f9","From Building Information Modelling to Digital Twins: Digital Representation for a Circular Economy","Koutamanis, A. (TU Delft Design & Construction Management)","De Wolf, Catherine (editor); Çetin, Sultan (editor); Bocken, Nancy (editor)","2024","Building information modelling (BIM) has ushered in the era of symbolic building representation: building elements and spaces are described not by graphical elements but by discrete symbols, each with properties and relations that explicitly integrate all information. Digital twinning promises even more: a digital replica in complete sync with the building and its behaviour. Such technologies have obvious appeal for circularity because they accommodate the rich information it requires and link circularity goals to other activities in AECO (architecture, engineering, construction and operation of buildings).
Present implementations of BIM may fall short of the promise, and digital twinning may be hard to achieve, but they remain crucial not only for circularity but for all AECO disciplines. To realise the potential of such representations, information should be treated not as a product of integration but as the integrator of all activities. Similarly, digitalisation should be at the core of business models and deployment plans, not an additional or even optional layer at a high cost. This calls for a coherent approach that includes the full capture of building information, supports the detailed exploration of circular operations, uses the results to constrain decisions and actions and does so throughout the life cycle.","information; digitalisation; representation; building information modelling (BIM); digital twinning","en","book chapter","Springer","","","","","","","","","","Design & Construction Management","","",""
"uuid:99c9eaf6-7253-461b-870a-5fb24f201bb6","http://resolver.tudelft.nl/uuid:99c9eaf6-7253-461b-870a-5fb24f201bb6","Stereological determination of particle size distributions for similar convex bodies","van der Jagt, T.F.W. (TU Delft Statistics); Jongbloed, G. (TU Delft Statistics); Vittorietti, M. (TU Delft Statistics; Università degli Studi di Palermo)","","2024","Consider an opaque medium that contains 3D particles. All particles are convex bodies of the same shape, but they vary in size. The particles are randomly positioned and oriented within the medium and cannot be observed directly. Taking a planar section of the medium we obtain a sample of observed 2D section profile areas of the intersected particles. In this paper, the distribution of interest is the underlying 3D particle size distribution for which an identifiability result is obtained. Moreover, a non-parametric estimator is proposed for this size distribution. The estimator is proven to be consistent and its performance is assessed in a simulation study.","consistency; EM; iterative convex minorant; Mellin transform; particle system; Stereology","en","journal article","","","","","","","","","","","Statistics","","",""
"uuid:ea315b12-deb8-428d-b0ab-342abfb02812","http://resolver.tudelft.nl/uuid:ea315b12-deb8-428d-b0ab-342abfb02812","Analysis of alkali-activated mineral wool-slag binders: evaluating the differences between one-part and two-part variations","Adesanya, Elijah (University of Oulu); Dabbebi, Rawia (University of Oulu); Rößler, Christine (Bauhaus University Weimar); Pavlin, Majda (Slovenian National Building and Civil Engineering Institute); Li, Z. (TU Delft Materials and Environment); Luukkonen, Tero (University of Oulu); Yliniemi, Juho (University of Oulu); Illikainen, Mirja (University of Oulu)","","2024","Two synthesis pathways (one- and two-part) in alkali-activated binders were compared using ground granulated blast furnace slag (GGBFS), mineral wool (MW) activated using dry and liquid alkali activators with similar Na2O/SiO2 modulus. The effect of activator type on reaction kinetics, strength development, setting times, and durability shows that one-part synthesis does not only improve early strength, but also provide better durability properties. While the highest compressive strength (56 MPa, 90 days) was achieved for the one-part mix (DM), the reaction products (presence of Mg–Al layered double hydroxide and C–S–H-like phases) observed for both mortar mixes were similar. The DM mortars showed better resistance to sulfate attack than two-part mix (WM) mortars and sets faster. The results highlight the significance of the one-part pathways in the synthesis of alkali-activated materials.","Alkali activation; Blast furnace slag; Glass wool; One-part; Stone wool; Two-part","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:ecd64e47-cb1f-415a-9748-3df608eba234","http://resolver.tudelft.nl/uuid:ecd64e47-cb1f-415a-9748-3df608eba234","What factors influence the intention to use electric motorcycles in motorcycle-dominated countries? An empirical study in Vietnam","Nguyen-Phuoc, Duy Quy (The University of Da Nang); Truong, Thi Minh (The University of Da Nang); Nguyen, Minh Hieu (University of Transport and Communications); Pham, Huong Giang (Foreign Trade University); Li, Z. (Huazhong University of Science and Technology); Oviedo-Trespalacios, O. (TU Delft Safety and Security Science)","","2024","Transitioning to electric motorcycles (EMs) can reduce dependence on carbon-based fuels, mitigate air pollution, and lower greenhouse gas emissions in countries where motorcycles dominate the transportation landscape. However, the factors influencing fleet electrification in these countries remain largely unknown. Given that this challenge pertains to the prior adoption of new technology, technology acceptance theories can provide valuable insights into the adoption of EMs. Additionally, misinformation about EM risks and self-assessment of knowledge could interact as determinants of adoption. This study integrates the Technology Acceptance Model (TAM), the Theory of Planned Behavior (TPB), and perceived risk to elucidate the impact of psychosocial factors on consumers' intentions to use EMs. Furthermore, it examines the direct and moderating effect of subjective knowledge about EM technology on the formation of this behavioral intention. Structural Equation Modeling (SEM) analysis was applied to investigate data collected from 762 respondents through personal interviews using a questionnaire. The results confirm that all original TAM and TPB constructs significantly influence behavioral intention, aligning with theoretical expectations. As hypothesized, perceived risk was found to exert a negative influence on the intention to adopt EMs. Additionally, subjective knowledge was observed to moderate the relationship between perceived usefulness and subjective norms concerning the intention to use EMs. These findings offer a roadmap for developing strategies aimed at encouraging adoption intentions toward EMs, particularly in countries like Vietnam.","Air pollution; Electric motorcycles; Perceived risk; Subjective knowledge; Sustainable transport","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-27","","","Safety and Security Science","","",""
"uuid:137ced4a-b7c4-427b-b699-c31ee2a3fcd6","http://resolver.tudelft.nl/uuid:137ced4a-b7c4-427b-b699-c31ee2a3fcd6","Kinematic Analysis and Application to Control Logic Development for RHex Robot Locomotion","Burzyński, Piotr (Bialystok University of Technology); Pawłuszewicz, Ewa (Bialystok University of Technology); Ambroziak, Leszek (Bialystok University of Technology); Sharma, Suryansh (TU Delft Networked Systems)","","2024","This study explores the kinematic model of the popular RHex hexapod robots which have garnered considerable interest for their locomotion capabilities. We study the influence of tripod trajectory parameters on the RHex robot’s movement, aiming to craft a precise kinematic model that enhances walking mechanisms. This model serves as a cornerstone for refining robot control strategies, enabling tailored performance enhancements or specific motion patterns. Validation conducted on a bespoke test bed confirms the model’s efficacy in predicting spatial movements, albeit with minor deviations due to motor load variations and control system dynamics. In particular, the derived kinematic framework offers valuable insights for advancing control logic, particularly navigating in flat terrains, thereby broadening the RHex robot’s application spectrum.","C-legged hexapod; mobile robot; walking robot; kinematics modeling; simulation","en","journal article","","","","","","This article belongs to the Special Issue Mobile Robots: Navigation, Control and Sensing.","","","","","Networked Systems","","",""
"uuid:de7b7d5c-8376-4979-8b93-0f20e135e823","http://resolver.tudelft.nl/uuid:de7b7d5c-8376-4979-8b93-0f20e135e823","Environmental risk assessment related to using resource recovery‑based bio‑composite materials in the aquatic environment with new laboratory leaching test data","Nativio, A. (TU Delft Sanitary Engineering); Jovanovic, O. (TU Delft Sanitary Engineering); van der Hoek, J.P. (TU Delft Sanitary Engineering); Kapelan, Z. (TU Delft Sanitary Engineering)","","2024","The concept of circular economy, aiming at increasing the sustainability of products and services in the water and other sectors, is gaining momentum worldwide. Driven by this concept, novel bio-composite materials produced by recovering resources from different parts of the water cycle are now manufactured in The Netherlands. The new materials are used for different products such as canal bank protection elements, as an alternative to similar elements made of hardwood. As much as these new materials are appealing from the sustainability point of view, they may leach toxic substances into the aquatic environment given some of their ingredients, e.g., cellulose recovered from wastewater treatment. Therefore, a methodology for the assessment of related environmental risks is needed and it does not exist currently. This paper addresses this knowledge gap by presenting a framework for this. The framework is based on European environmental risk assessment guidelines, and it includes four key steps: (i) hazard identification, (ii) dose–response modelling, (iii) exposure assessment and (iv) risk characterisation (i.e. assessment). As part of the first step, laboratory leaching tests were carried out to evaluate the potential release of specific chemical substances such as heavy metals and resin compounds into the aquatic environment. Laboratory test results were then used as input data to evaluate the risk of potential leaching from canal bank protection elements into surface water. A deterministic model was used first to identify the chemicals exceeding the guideline threshold. Subsequently, a stochastic model was applied to evaluate the environmental risks across a range of leachate concentrations and water velocities in the canal, thereby simulating a broader spectrum of possible situations. The risk analyses were conducted for four alternative bio-composite materials made of different ingredients, two different flow conditions (stagnant water and advective flow) in two types of canals (wide ditch and primary watercourse) and for two different water levels based on season conditions (summer and winter conditions). The results obtained from leaching tests identified Cu, Mn, Zn, styrene and furfuryl alcohol as potentially troublesome chemicals. In the case of stagnant water, the absence of a flow rate increases the residence time of the chemicals in the surface water, resulting in a higher PEC/PNEC (i.e. risk) value. However, under stagnant case conditions, environmental risks for all chemicals considered turned out to be below the safety threshold. In the advective case, the existence of a flow rate, even at low velocities simulating the conditions of ‘almost no flow,’ contributes to increased dilution, resulting in lower PEC/PNEC ratio values. The results presented here, even though representing real-case scenarios, are only indicative as these are based on laboratory leaching tests and a number of assumptions made. Additional field tests involving collecting and analysing water and sediment samples from the canal where the canal bank protection elements are located, over a prolonged period, are required to come up with more conclusive findings.","Bio-composite materials; Canal bank protection environmental risk assessment; Heavy metal contamination; Leaching tests; Sensitivity analysis; Surface water","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:406ff669-7a1c-48e7-ba22-ff917ce0094f","http://resolver.tudelft.nl/uuid:406ff669-7a1c-48e7-ba22-ff917ce0094f","Maximizing ollie height by optimizing control strategy and skateboard geometry using direct collocation","Heinen, Jan T. (Student TU Delft); Brockie, S.G. (TU Delft Biomechatronics & Human-Machine Control); ten Broek, Raymund (Urbansports Performance Centre); van der Kruk, E. (TU Delft Biomechatronics & Human-Machine Control); Moore, J.K. (TU Delft Biomechatronics & Human-Machine Control)","","2024","The ollie is the base aerial human–board maneuver, foundational to most modern skateboarding tricks. We formulate and solve an optimal control problem of a two-dimensional simplified human model and a rigid body skateboard with the objective of maximizing the height of the ollie. Our solution simultaneously discovers realistic human-applied force trajectories and optimal board geometry. We accomplish this with a direct collocation formulation using a null seed initial guess by carefully modeling the discontinuous aspects of board–ground impact and foot–board friction. This leads to efficient and robust solutions that are 10 times more computationally efficient than prior work on similar problems. The solutions show that ollie height can increase 3% by decreasing the wheelbase and that a smaller board with a back-foot-dominated force strategy can give 12% higher ollies. Our model can be used to inform jump strategy and the effects of changes to the essential board geometry.","Direct collocation; Friction; Impact; Optimal control; Parameter optimization; Skateboarding; Trajectory optimization","en","journal article","","","","","","","","","","","Biomechatronics & Human-Machine Control","","",""
"uuid:4386cd46-00c0-475a-bcfd-3e56380b9f3c","http://resolver.tudelft.nl/uuid:4386cd46-00c0-475a-bcfd-3e56380b9f3c","A Fully-Focused SAR Omega-K Closed-Form Algorithm for the Sentinel-6 Radar Altimeter: Methodology and Applications","Hernandez-Burgos, Sergi (Universitat Politecnica de Catalunya); Gibert, Ferran (IsardSAT); Broquetas, Antoni (Universitat Politecnica de Catalunya); Kleinherenbrink, M. (TU Delft Mathematical Geodesy and Positioning); De la Cruz, Adrian Flores (IsardSAT); Gomez-Olive, Adria (IsardSAT); Garcia-Mondejar, Albert (IsardSAT); Aparici, Monica Roca i. (IsardSAT)","","2024","The 2-D frequency-based omega-K method is known to be a suitable algorithm for fully focused SAR (FF-SAR) radar altimeter processors, as its computational efficiency is much higher than equivalent time-based alternatives without much performance degradation. In this article, we provide a closed-form description of a 2-D frequency-domain omega-K algorithm specific for instruments such as Poseidon-4 onboard Sentinel-6. The processor is validated with real data from point targets and over the open ocean. Applications such as ocean swell retrieval and lead detection are demonstrated, showing the potentiality of the processor for future operational global-scale products.","Altimetry; delay/Doppler altimetry; Earth; Fully-Focused SAR; omega-K; Program processors; Radar antennas; SAR altimetry; Satellites; Spaceborne radar; Synthetic aperture radar; synthetic aperture radar (SAR)","en","journal article","","","","","","","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:98dbb10d-8911-49d2-8a36-17fc5be73129","http://resolver.tudelft.nl/uuid:98dbb10d-8911-49d2-8a36-17fc5be73129","Stationary-phase analysis of time-shift extended imaging in a constant-velocity model","Mulder, W.A. (TU Delft Applied Geophysics and Petrophysics; Shell Global Solutions International B.V.)","","2024","To estimate the depth errors in a subsurface model obtained from the inversion of seismic data, the stationary-phase approximation in a two-dimensional constant-velocity model with a dipped reflector is applied to migration with a time-shift extension. This produces two asymptotic solutions: one is a straight line, and the other is a curve. If the velocity differs from the true one, a closed-form expression of the depth error follows from the depth and apparent dip of the reflector as well as the position of the amplitude peak at a non-zero time shift, where the two solutions meet and the extended migration image focuses. The results are compared to finite-frequency results from a finite-difference code. A two-dimensional synthetic example with a salt diapir illustrates how depth errors can be estimated in an inhomogeneous model after inverting the seismic data for the velocity model.","computing aspects; inverse problem; mathematical formulation; seismics; wave","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:48d9c7aa-c573-439d-8d5f-454127a4886b","http://resolver.tudelft.nl/uuid:48d9c7aa-c573-439d-8d5f-454127a4886b","Atmospheric Correction Algorithms Assessment for Sentinel-2A Imagery over Inland Waters of China: Case Study, Qiandao Lake","Allam, Mona (Chinese Academy of Sciences; National Water Research Center, Egypt); Meng, Qingyan (Chinese Academy of Sciences; University of Chinese Academy of Sciences; Hainan Aerospace Information Research Institute); Elhag, Mohamed (King Abdulaziz University; Chinese Academy of Sciences; CI-HEAM/Mediterranean Agronomic Institute of Chania; German University of Technology in Oman); Giardino, Claudia (Institute for Electromagnetic Sensing of the Environment); Ghirardi, Nicola (Institute for Electromagnetic Sensing of the Environment); Su, Yi (Fudan University); Al-Hababi, Mohammed A.M. (University of Chinese Academy of Sciences); Menenti, M. (TU Delft Optical and Laser Remote Sensing)","","2024","Around 90% of the oceanic and inland waters’ reflectance registered in satellite detectors comes from the atmospheric contribution. Hence the water-leaving radiances in the Near-InfraRed (NIR) region are above the zero value over inland waters because of sediments and dissolved organic particles, this radiance cannot be ignored. To accurately retrieve water quality parameters from water-leaving reflectance, atmospheric correction is the most important step. This study evaluated five reliable atmospheric correction algorithms (AC) known as: (ACOLITE, C2RCC, iCOR, 6SV, and Sen2Cor) against optical in-situ measurements collected above the water in Qiandao Lake, China using Sentinel-2 Multi-Spectral Imager. 60 in-situ water samples and optical measurements (range 400–900 nm) above the water were collected at different points in Qiandao Lake. The spectra measurements were used to validate the atmospheric correction processors. All ACs that were evaluated showed high levels of uncertainty. ACOLITE and ICOR performed the best statistics with root mean square differences (RMSD) (0.006 sr−1) while Sen2Cor achieved the lowest RMSD (0.023 sr−1) across the different modules. ACOLITE, had a better performance when applied to meso- and hypereutrophic waters, compared with oligotrophic, while C2RCC performs better at the wavelength of 833 nm (0.007 sr−1). Finally, 6S performs better at the wavelength of 665 nm (0.015 sr−1). This study introduces insights and addresses a significant research gap in the field of atmospheric correction for satellite imagery over inland waters. Prior studies have primarily focused on atmospheric correction algorithms for coastal and open ocean environments while few studies focused on the unique characteristics and challenges associated with inland water bodies. The findings of this study are crucial for researchers, remote sensing experts, and environmental scientists working with Sentinel-2A imagery, as it enables them to make more accurate and reliable interpretations of water quality and other environmental parameters derived from satellite data.","Atmospheric correction; Inland Water; Qiandao Lake; Sentinel-2","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-18","","","Optical and Laser Remote Sensing","","",""
"uuid:e6c7d642-e759-413c-bb05-acbe889c1a31","http://resolver.tudelft.nl/uuid:e6c7d642-e759-413c-bb05-acbe889c1a31","Improved drought forecasting in Kazakhstan using machine and deep learning: a non-contiguous drought analysis approach","Sadrtdinova, Renata (IHE Delft Institute for Water Education); Perez, Gerald Augusto Corzo (IHE Delft Institute for Water Education); Solomatine, D.P. (TU Delft Water Resources; IHE Delft Institute for Water Education; Water Problems Institute of Russian Academy of Sciences)","","2024","Kazakhstan is recently experiencing an increase in drought trends. However, low-capacity probabilistic drought forecasts and poor dissemination have led to a drought crisis in 2021 that resulted in the loss of thousands of livestock. To improve drought forecasting accuracy, this study applies Machine Learning and Deep Learning (ML and DL) algorithms to capture the sequences of drought events using a non-contiguous drought analysis (NCDA). Precipitation, 2-m temperature, runoff, solar radiation, relative humidity, and evaporation were collected from the ERA5 database as input variables. Combinations of inputs were used to build ML models, including seven classifiers (Logistic, K-NN, Kernel SVM, Decision Tree, Random Forest, XGBoost, and GRU). The output events were defined by standardized precipitation index (SPI) and SPEI indicators as binary classes. Weekly time series from 1991 to 2021 for each cell were used to forecast a lead time from 1 week to 6 months. GRU provided 97–99% accuracy in more volatile regions while Random Forest and XGBoost showed 94–99% accuracy at a lead time of 6 months. The accuracy evaluation was based on the confusion matrix and F1 score to analyze the stage change capture. This study demonstrates the effectiveness of using ML and DL algorithms for drought forecasting, with potential applications for other regions.","deep learning; machine learning; NCDA; spatiotemporal drought forecasting; SPEI; SPI","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:83bf377c-cb5d-4a4c-a018-8054c23fca50","http://resolver.tudelft.nl/uuid:83bf377c-cb5d-4a4c-a018-8054c23fca50","System-Wide Effects of Local Bed Disturbance on the Morphological Evolution of a Bifurcating Channel Network","Gao, Weilun (Guangdong University of Technology); Shao, Dongdong (Beijing Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Zhu, Zhenchang (Guangdong University of Technology; Southern Marine Science and Engineering Guangdong Laboratory); Yang, Zhifeng (Guangdong University of Technology; Southern Marine Science and Engineering Guangdong Laboratory)","","2024","Deltaic channel networks are important conduits for water and material supplies to the fluvial and coastal communities. However, increasing human interventions in river deltas have altered the topology and geometry of channel networks as well as their long-term evolution. While the morphological evolution of a single channel has received extensive studies, the system-wide morphological responses of channel networks to local disturbances remain largely unclear. Here we investigate the morphological responses of a bifurcating channel network subject to local disturbance of channel deepening due to dredging and sand mining through idealized simulations, and further compare the results with the reference scenarios of a single channel and theoretical analysis of the phase plane. The results show that the infilling of the local deepening is associated with the erosion of the entire branch, which also causes system-wide effects on the siltation of the other branch. The morphological responses of the bifurcating channel network consist of a relatively short stage for the infilling of the local deepening followed by a relatively long stage for recovering the equilibrium configuration of the river bifurcation. The system-wide effects of the local disturbance arise from the altered water surface slope and water partitioning downstream of the bifurcation due to the local deepening. Also, the prolonged recovery of the equilibrium configuration is consistent with theoretical analysis, which reveals a slow evolution of the bifurcation when approaching the equilibrium. Our results can help understand the long-term morphological responses of large-scale complex channel networks and inform water managements under increasing human interventions.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-26","","","Coastal Engineering","","",""
"uuid:2e364ed0-c104-4ca9-8f66-f5c0e5778a6a","http://resolver.tudelft.nl/uuid:2e364ed0-c104-4ca9-8f66-f5c0e5778a6a","Tools and methods for monitoring the health of the urban greenery","Gupta, A. (TU Delft Water Resources; Massachusetts Institute of Technology); Mora, Simone (Massachusetts Institute of Technology; Norwegian University of Science and Technology (NTNU)); Preisler, Yakir (Harvard University); Duarte, Fábio (Massachusetts Institute of Technology); Venkatesha Prasad, Ranga Rao (TU Delft Networked Systems); Ratti, Carlo (Massachusetts Institute of Technology; Politecnico di Milano)","","2024","Urban greenery supports cities in achieving Sustainable Development Goals, but it is increasingly affected by multiple stressors impacting its health. Owing to the high costs of greenery inspection and monitoring, local governments often lack adequate data to effectively manage their urban greenery and prevent damage. In this Review, we present an overview of technology-supported methods and tools to measure the health of urban greenery and discuss the space–time resolution trade-offs associated with the various methods presented. To inform researchers and policymakers in global cities, we highlight how high-resolution urban greenery health data can support in achieving Sustainable Development Goals at scale.","","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-04","","","Water Resources","","",""
"uuid:ab018a53-1a65-4fa4-be77-37e23dd90abe","http://resolver.tudelft.nl/uuid:ab018a53-1a65-4fa4-be77-37e23dd90abe","Accounting for uncertainties in forecasting tropical-cyclone-induced compound flooding","Nederhoff, C.M. (TU Delft Coastal Engineering; Deltares; IHE Delft Institute for Water Education); van Ormondt, M. (Deltares); Veeramony, Jay (NASA Stennis Space Center); van Dongeren, Ap (IHE Delft Institute for Water Education; Deltares); Antolínez, José A. Á. (TU Delft Coastal Engineering); Leijnse, Tim (Deltares; Vrije Universiteit Amsterdam); Roelvink, D. (IHE Delft Institute for Water Education; Deltares)","","2024","Tropical-cyclone impacts can have devastating effects on the population, infrastructure, and natural habitats. However, predicting these impacts is difficult due to the inherent uncertainties in the storm track and intensity. In addition, due to computational constraints, both the relevant ocean physics and the uncertainties in meteorological forcing are only partly accounted for. This paper presents a new method, called the Tropical Cyclone Forecasting Framework (TC-FF), to probabilistically forecast compound flooding induced by tropical cyclones, considering uncertainties in track, forward speed, and wind speed and/or intensity. The open-source method accounts for all major relevant physical drivers, including tide, surge, and rainfall, and considers TC uncertainties through Gaussian error distributions and autoregressive techniques. The tool creates temporally and spatially varying wind fields to force a computationally efficient compound-flood model, allowing for the computation of probabilistic wind and flood hazard maps for any oceanic basin in the world as it does not require detailed information on the distribution of historical errors. A comparison of TC-FF and JTWC operational ensembles, both based on DeMaria et al. (2009), revealed minor differences of <10 %, suggesting that TC-FF can be employed as an alternative, for example, in data-scarce environments. The method was applied to Cyclone Idai in Mozambique. The underlying physical model showed reliable skill in terms of tidal propagation, reproducing the storm surge generation during landfall and flooding near the city of Beira (success index of 0.59). The method was successfully applied to forecasting the impact of Idai with different lead times. The case study analyzed needed at least 200 ensemble members to get reliable water levels and flood results 3 d before landfall (<1 % flood probability error and <20 cm sampling errors). Results showed the sensitivity of forecasting, especially with increasing lead times, highlighting the importance of accounting for cyclone variability in decision-making and risk management.","","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:0bf19746-1611-47d2-a9b2-44b42a023c99","http://resolver.tudelft.nl/uuid:0bf19746-1611-47d2-a9b2-44b42a023c99","Conservation and development of the historic garden in a landscape context: A systematic literature review","Lian, J.S. (TU Delft Landscape Architecture); Nijhuis, S. (TU Delft Landscape Architecture); Bracken, G. (TU Delft Spatial Planning and Strategy); Wu, Xiangyan (Central Academy of Fine Arts (CAFA)); Wu, Xiaomin (Central Academy of Fine Arts (CAFA)); Chen, Dong (Central Academy of Fine Arts (CAFA))","","2024","Although there have been numerous studies on the heritage attributes, characteristics, and values of the historic garden as a special category of cultural heritage, the question is why a comprehensive review combining mainstream historic garden conservation with ways of understanding the garden in a landscape context has not been conducted. Landscape is an integrative concept that combines physical features and the diversity of functions with social and ecological processes throughout the scales of time and space. Therefore, this landscape context means applying the landscape approach to explore the organic connection between the scale of evolution and the architectonic elements in relation to each other. To elaborate, instead of viewing the garden as an object in one specific temporal-spatial frame, such an approach focuses on the evolution of the site in order to identify persistent structures and other values. The method used in this study involved paper coding as qualitative analysis combined with bibliometric visualization software. We reviewed 162 studies to explore the interconnections between the historic garden and landscape approach. The result is that there are three correspondences between landscape approaches and different stages of the historic garden’s conservation and development: studies identifying the historic garden’s characteristics using landscape mapping, studies demonstrating historic gardens’ conservation based on landscape planning, and studies exploring the potential of development and reuse through landscape design. Finally, we discuss the research gaps and outline an action framework for the conservation and development of heritage gardens in a landscape context.","Cultural heritage; Historic garden; Conservation; Development; Landscape approach","en","review","","","","","","","","","","","Landscape Architecture","","",""
"uuid:5230f0c9-a59d-4acd-8cad-d2d8ad9b4bd5","http://resolver.tudelft.nl/uuid:5230f0c9-a59d-4acd-8cad-d2d8ad9b4bd5","Accumulation of floating particles at hydraulic structures","Magherini, A. (TU Delft Civil Engineering & Geosciences); Yan Toe, C. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Stancanelli, L.M. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Wüthrich, D. (TU Delft Hydraulic Structures and Flood Risk); Uijttewaal, W.S.J. (TU Delft Environmental Fluid Mechanics)","","2024","Plastic pollution is a threat for all ecosystems due to its effects on people, animals, and environment (Mai et al., 2020). Rivers are estimated to transport around 0.5 millions tons of plastic per year (Strokal et al., 2023). When plastic enters a river system, it is transported downstream towards the sea but it is also likely to accumulate at specific cross sections and locations, including hydraulic structures (Al-Zawaidah et al., 2021), eventually increasing the risk of floods.
Gates, locks, weirs, and bridges are commonly present in rivers and canals and have several functions, including water level reg-ulation, flood safety, and inland water shipping. These can also be found in water treatment plants, hydropower stations as well as debris/plastic collection systems (Honingh et al., 2020). Riverine plastic accumulation is also known to cause geomorphic changes (Al-Zawaidah et al., 2021).
In-depth knowledge on how plastic particles accumulate upstream of hydraulic structures is therefore crucial to understand the processes that affect plastic transport, its influence on the safety and functionality of hydraulic structures and their effects on the hydro- and morphody-namic conditions of the flow (Yan Toe et al., 2022).
In this research experiments were performed using simplified plastic particles to analyse the processes that lead to the instability of accumulated particles upstream of a simple gate.","plastic accumulation; hydraulic structures; carpet instability; erosion","en","abstract","","","","","","","","","Civil Engineering & Geosciences","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:acf174cb-4aa1-4a52-81e0-7afe94aec072","http://resolver.tudelft.nl/uuid:acf174cb-4aa1-4a52-81e0-7afe94aec072","Hybrid geometry sets for global registration of cross-source geometric data","Li, Minglei (Nanjing University of Aeronautics and Astronautics); Peng, Shu (Nanjing University of Aeronautics and Astronautics); Nan, L. (TU Delft Urban Data Science)","","2024","We propose a concept of hybrid geometry sets for registering cross-source geometric data. Specifically, our method focuses on the coarse registration of geometric data obtained from laser scanning and photogrammetric reconstruction. Due to different characteristics (e.g., variations in noise levels, density, and scales), achieving accurate registration between these data becomes a challenging task. The proposed method uses geometric structures to construct hybrid geometry sets, and the geometric relations between the elements of a hybrid geometry set are encoded in a hybrid feature space. This enables effective and efficient similarity query and correspondence establishment between the hybrid geometry sets. The proposed global registration method works in three steps. Firstly, a set of hybrid geometry sets is constructed using extracted planes and intersection lines. Then the features of the hybrid geometry sets are computed to encode the relative pose and topological relationships between the extracted planes and intersection lines, and their correspondences between the two inputs are established by querying hybrid geometry sets with similar features. Finally, the global registration parameters are calculated using the correspondences, and the registration result is further refined through continuous optimization. The robustness of the method has been evaluated using different real-world cross-source geometric data of urban scenes. Extensive comparisons with state-of-the-art algorithms have also demonstrated its effectiveness.","Cross-source geometric data; Global registration; Hybrid geometry sets; Scale restoration","en","journal article","","","","","","","","","","","Urban Data Science","","",""
"uuid:eefa4cec-3d38-41bd-ab13-13c9cce3fd70","http://resolver.tudelft.nl/uuid:eefa4cec-3d38-41bd-ab13-13c9cce3fd70","Subsidy allocation for residential building energy retrofit: A perspective of families' incomes","You, K. (TU Delft Design & Construction Management; Chongqing University; Beijing Institute of Technology); Qian, QK (TU Delft Design & Construction Management); Cai, Weiguang (Chongqing University); Wang, Xia (Southwestern University of Finance and Economics); Visscher, H.J. (TU Delft Design & Construction Management)","","2024","High household end-user services demand of high-income families results in higher energy consumption compared with low-income families, indicating high-income families may save more energy from similar building energy retrofitting (BER) strategies. Therefore, current BER subsidy policies, which consider technique indicators and ignore families' income, will make high-income families' recovery costs faster, and can't maximize the incentive for residents’ BER awareness. To formulate a equitable and efficient subsidy policies considering families’ income, this study selected Chongqing as the study case and employed propensity scores matching method to evaluate BER's actual energy savings performance for families with different incomes. Meanwhile, the BER subsidies are reallocated based on the dynamic cost payback period. The results indicated that, following BER, the energy savings of high-income families (7.36 kWh/m2) were higher than the mid- (3.96 kWh/m2) and low-income (3.25 kWh/m2) families. Notably, under current subsidy policies, the cost payback period of low-income families is nearly 2.55 and 3.14 times of the mid-income (6.61 years) and high-income (5.37 years) groups, respectively. This study suggests a subsidy of 32.57 yuan/m2, 20.27 yuan/m2, and 15.38 yuan/m2 for low-income, mid-income, and high-income families, respectively. These results provide novel insights into the actual energy-saving performance of residential buildings and help policymakers to formulate fair subsidy policies.","Actual energy savings performance; Building energy efficiency standard; Building energy retrofit; Income; Subsidy allocation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-28","","","Design & Construction Management","","",""
"uuid:cbda0b8e-6d7e-45f5-a6ea-d12e0f2fc86d","http://resolver.tudelft.nl/uuid:cbda0b8e-6d7e-45f5-a6ea-d12e0f2fc86d","Effect of struts and central tower on aerodynamics and aeroacoustics of vertical axis wind turbines using mid-fidelity and high-fidelity methods","Shubham, Shubham (Nottingham Trent University; Cranfield University); Avallone, F. (Politecnico di Torino); Brandetti, L. (TU Delft Wind Energy); Wright, Nigel (University of Birmingham); Ianakiev, Anton (Nottingham Trent University)","","2024","This study investigates the impact of struts and a central tower on the aerodynamics and aeroacoustics of Darrieus Vertical Axis Wind Turbines (VAWTs) at chord-based Reynolds numbers of 8.12e4. A 2-bladed H-Darrieus VAWT is used, featuring a 1.5m diameter, a solidity of 0.1 and a blade cross-section of symmetrical NACA 0021. The turbine design is kept simple and straight-bladed which is essential for isolating and analyzing the specific effects of struts and a tower. The high-fidelity Lattice Boltzmann Method (LBM) in PowerFLOW 6-2020 and the mid-fidelity Lifting Line Free Vortex Wake (LLFVW) method in QBlade 2.0 are employed, with the mid-fidelity method providing a faster analytical tool for insights into the turbine performance. Firstly, both the LLFVW (mid-fidelity) and LBM (high-fidelity) methods effectively capture the general trends observed in VAWT power performance. However, the former predicts mean thrust values that are approximately 10% higher, and mean torque values that are approximately 19% higher, in comparison to the latter. Subsequently, the former predicts lower streamwise wake velocities relative to those predicted by the latter. These differences increase in configurations that include struts and a tower (to 30% - 31%). Secondly, the presence of struts and a tower leads to a reduction in both mean power (by 15% to 55%) and thrust (by 3% to 3.6%), with a further small decrease observed when doubling the tower diameter (power and thrust both by 0.5% to 3%). The struts predominantly affect the spanwise distribution of blade loading, while the tower impacts the azimuthal variation of blade loading. Additionally, the addition of struts and a tower reduces low-frequency noise (50-200 Hz) while increasing high-frequency noise (> 300 Hz). The observed decrease in mean blade loading results in reduced low-frequency noise, while the increase in high-frequency noise is ascribed to the increased intensity of BWI/BVI leading to higher unsteady loading fluctuations on blades.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Wind Energy","","",""
"uuid:ae7cee14-edbb-4b00-8010-fff67d5b69f5","http://resolver.tudelft.nl/uuid:ae7cee14-edbb-4b00-8010-fff67d5b69f5","Complicating the debate: Evaluating the potential of gas-chromatography-mass spectrometry for differentiating prehistoric aceramic tar production techniques","Chasan, R. (TU Delft Team Joris Dik); Baron, L.I. (TU Delft ChemE/O&O groep); Kozowyk, P.R.B. (TU Delft Team Joris Dik); Langejans, G.H.J. (TU Delft Team Joris Dik; University of Johannesburg)","","2024","Birch bark tar was used extensively throughout human history. While later ceramic-based production technologies are known, prehistoric aceramic techniques leave little to no archaeological evidence. Experimental tar production attempts to fill this gap and suggest potential techniques. However, their archaeological relevance is unclear. Through an in-depth biomolecular analysis using Gas Chromatography-Mass Spectrometry, this study attempts to differentiate tars produced using four experimental aceramic techniques: condensation, ash mound, pit roll, and raised structure. In doing so we publish the largest collection of GC-MS results of aceramic birch tars. The results show that pentacyclic triterpenoids, characteristic of birch bark, vary between the production techniques in relation to heating exposure and perhaps the tar collection method. This allows for a tentative identification of tars produced through the condensation and ash mound techniques, which were formed consistently using short periods of heating and collected systematically by scraping. In contrast, tars produced using the pit roll and raised structure techniques do not have consistent molecular signatures. Despite the partial success of Gas Chromatography-Mass Spectrometry, the archaeological relevance is questioned because this technique is only applicable to samples from optimum lipid preservation conditions when a high number of pentacyclic triterpenoids are preserved. Therefore, using Gas Chromatography-Mass Spectrometry to determine the transformation methods of organics, like birch bark, may not be an appropriate standalone technique to fairly discuss the technological capabilities of past populations.","Adhesives; Ancient technology; Birch tar; Gas Chromatography-mass spectrometry; Organic residue analysis; Prehistory; Terpenoids","en","journal article","","","","","","","","","","","Team Joris Dik","","",""
"uuid:5143fd20-6abd-4d34-b60f-5034124dc1e9","http://resolver.tudelft.nl/uuid:5143fd20-6abd-4d34-b60f-5034124dc1e9","The potential of end-of-life ships as a floating seawall and the methodical use of gap resonance for wave attenuation","Wang, G. (TU Delft Ship Hydromechanics and Structures; Technion); Bar, Daniel (Technion); Schreier, S. (TU Delft Ship Hydromechanics and Structures)","","2024","This study examines the potential of a new type of floating seawall, made up of retired large-scale oceangoing vessels, to be used in open water and exposed coastal areas. The main objectives of the research are to assess the effectiveness of the floating seawall concept, to determine the contribution of the gap resonance to wave attenuation, and to compare the results of physical tests with those obtained numerically using ANSYS-AQWA. The use of end-of-life ships in this way provides a unique opportunity to extend their life cycle and reduce the environmental and human health risks associated with the current practice of shipbreaking. The research focuses on a multimodule floating seawall configuration, where each module is composed of two hulls that are rigidly connected side by side, with a small gap to induce gap resonance. The results suggest that end-of-life ships can be used as a resource for the construction of floating seawalls for various marine applications. Furthermore, the results demonstrate the positive influence of the gap resonance on the wave attenuation capacity of the seawall, as well as the limitations of the numerical tool in providing realistic values in this region.","Floating breakwaters; Floating structures; Gap resonance; Hydrodynamic interaction; Ocean and sea space utilization; Wave transmission coefficient","en","journal article","","","","","","","","","","","Ship Hydromechanics and Structures","","",""
"uuid:a0cd6902-6dc9-43dc-9779-6098e29843ad","http://resolver.tudelft.nl/uuid:a0cd6902-6dc9-43dc-9779-6098e29843ad","The concept of circular water value and its role in the design and implementation of circular desalination projects. The case of coal mines in Poland","Xevgenos, Dimitris (TU Delft Energie and Industrie; Sealeau); Tourkodimitri, K. Panteleaki (Student TU Delft); Mortou, M. (Sealeau); Mitko, K. (Silesian University of Technology); Sapoutzi, D. (Sealeau); Stroutza, D.E. (TU Delft BT/Biotechnology and Society); Turek, M. (Silesian University of Technology); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)","","2024","Circular economy has become a popular subject, attracting attention from academics, practitioners, and policy-makers alike. However, despite the excitement surrounding it, the concept of circular economy has been criticized for being vague and having multiple interpretations from different fields. As a result, there is a lack of evidence and guidance for practitioners, making it difficult to put into practice. Our goal is to fill this gap by bridging the design and implementation of circular economy solutions in the water sector. Through an exploratory study of two case studies, we have shown the significance of what we call as “circular water value” in the context of coal mining. This value is strongly influenced by the chemistry, concentration levels and purity of these effluents. We compared the circular value of the two cases (ranging from 2.5 to 6 euros per cubic meter) to the cost of the novel treatment system, developed by the authors through the EU-funded project ZERO BRINE, to capture this value. This allowed us to evaluate the potential for circular economy implementation. We suggest that this circular transition can offer significant opportunities to coal mining regions in enabling a just transition implementation. This is a topic that is increasingly gaining interest among academic and practitioner communities, further triggered by the recently adopted Just Transition Mechanism. This mechanism secures targeted support of 55 billion euro for the period 2021–2027 for the most affected regions within Europe. The concept of “circular water value” introduced in this article can serve as a tool for exploring the creation of emerging circular value chains from coal mines, as well as for other wastewater treatment and resource recovery projects in general.","Brine treatment; Circular business models; Circular economy,; Coal mine wastewater; Desalination,; Design for sustainability; Resource recovery; Salts; Water","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:e230fab5-afda-41f9-93cf-0ce8c6020f64","http://resolver.tudelft.nl/uuid:e230fab5-afda-41f9-93cf-0ce8c6020f64","The organo-metal-like nature of long-range conduction in cable bacteria","Pankratov, Dmitrii (Universiteit Antwerpen); Hidalgo Martinez, Silvia (Universiteit Antwerpen); Karman, Cheryl (Universiteit Antwerpen); Gerzhik, Anastasia (Forschungszentrum Jülich GmbH); Gomila, Gabriel (Barcelona Institute of Science and Technology (BIST); Universitat de Barcelona); Trashin, Stanislav (Universiteit Antwerpen); Boschker, H.T.S. (TU Delft BT/Environmental Biotechnology; Universiteit Antwerpen); Geelhoed, Jeanine S. (Universiteit Antwerpen); Meysman, F.J.R. (TU Delft BT/Environmental Biotechnology; Universiteit Antwerpen)","","2024","Cable bacteria are filamentous, multicellular microorganisms that display an exceptional form of biological electron transport across centimeter-scale distances. Currents are guided through a network of nickel-containing protein fibers within the cell envelope. Still, the mechanism of long-range conduction remains unresolved. Here, we characterize the conductance of the fiber network under dry and wet, physiologically relevant, conditions. Our data reveal that the fiber conductivity is high (median value: 27 S cm−1; range: 2 to 564 S cm−1), does not show any redox signature, has a low thermal activation energy (Ea = 69 ± 23 meV), and is not affected by humidity or the presence of ions. These features set the nickel-based conduction mechanism in cable bacteria apart from other known forms of biological electron transport. As such, conduction resembles that of an organic semi-metal with a high charge carrier density. Our observation that biochemistry can synthesize an organo-metal-like structure opens the way for novel bio-based electronic technologies.","Bioelectronics; Cable bacteria; Electrochemical impedance spectroscopy; Long-distance electron transport; Protein conductivity","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:c944ae79-0b9a-4522-bef4-3a858fc9d4b3","http://resolver.tudelft.nl/uuid:c944ae79-0b9a-4522-bef4-3a858fc9d4b3","Mitigating Motion Sickness with Optimization-Based Motion Planning","Zheng, Y. (TU Delft Intelligent Vehicles); Shyrokau, B. (TU Delft Intelligent Vehicles); Keviczky, T. (TU Delft Team Tamas Keviczky)","","2024","The acceptance of automated driving is under the potential threat of motion sickness. It hinders the passengers' willingness to perform secondary activities. In order to mitigate motion sickness in automated vehicles, we propose an optimization-based motion planning algorithm that minimizes the distribution of acceleration energy within the frequency range that is found to be the most nauseogenic. The algorithm is formulated into integral and receding-horizon variants and compared with a commonly used alternative approach aiming to minimize accelerations in general. The proposed approach can reduce frequency-weighted acceleration by up to 11.3% compared with not considering the frequency sensitivity for the price of reduced overall acceleration comfort. Our simulation studies also reveal a loss of performance by the receding-horizon approach over the integral approach when varying the preview time and nominal sampling time. The computation time of the receding-horizon planner is around or below the real-time threshold when using a longer sampling time but without causing significant performance loss. We also present the results of experiments conducted to measure the performance of human drivers on a public road section that the simulated scenario is actually based on. The proposed method can achieve a 19% improvement in general acceleration comfort or a 32% reduction in squared motion sickness dose value over the best-performing participant. The results demonstrate considerable potential for improving motion comfort and mitigating motion sickness using our approach in automated vehicles.","Automated vehicles; motion planning; motion sickness; real-time optimization","en","journal article","","","","","","","","","","","Intelligent Vehicles","","",""
"uuid:4d81be6f-c414-41e9-809e-00f449442def","http://resolver.tudelft.nl/uuid:4d81be6f-c414-41e9-809e-00f449442def","New Theoretical Model to Describe Carrier Multiplication in Semiconductors: Explanation of Disparate Efficiency in MoTe2 versus PbS and PbSe","Weerdenburg, S. (TU Delft ChemE/Catalysis Engineering); Singh, N. (TU Delft ChemE/Opto-electronic Materials); van der Laan, Marco (Institute for Theoretical Physics Amsterdam); Kinge, Sachin (Toyota Motor Europe); Schall, Peter (Institute for Theoretical Physics Amsterdam); Siebbeles, L.D.A. (TU Delft ChemE/Opto-electronic Materials)","","2024","We present a theoretical model to compute the efficiency of the generation of two or more electron-hole pairs in a semiconductor by the absorption of one photon via the process of carrier multiplication (CM). The photogeneration quantum yield of electron-hole pairs is calculated from the number of possible CM decay pathways of the electron and the hole. We apply our model to investigate the underlying cause of the high efficiency of CM in bulk 2H-MoTe2, as compared to bulk PbS and PbSe. Electronic band structures were calculated with density functional theory, from which the number of possible CM decay pathways was calculated for all initial electron and hole states that can be produced at a given photon energy. The variation of the number of CM pathways with photon energy reflects the dependence of experimental CM quantum yields on the photon energy and material composition. We quantitatively reproduce experimental CM quantum yields for MoTe2, PbS, and PbSe from the calculated number of CM pathways and one adjustable fit parameter. This parameter is related to the ratio of Coulomb coupling matrix elements and the cooling rate of the electrons and holes. Large variations of this fit parameter result in small changes in the modeled quantum yield for MoTe2, which confirms that its high CM efficiency can be mainly attributed to its extraordinary large number of CM pathways. The methodology of this work can be applied to analyze or predict the CM efficiency of other materials.","","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:998d3bf0-6ea9-48f2-96fb-e2cd8964966b","http://resolver.tudelft.nl/uuid:998d3bf0-6ea9-48f2-96fb-e2cd8964966b","Progress in Engineering Synthetic Cells and Cell-Free Systems","Dogterom, A.M. (TU Delft BN/Marileen Dogterom Lab); Kamat, Neha P. (Northwestern University); Jewett, Michael C. (Stanford University); Adamala, Katarzyna P. (University of Minnesota Twin Cities)","","2024","","","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-02","","","BN/Marileen Dogterom Lab","","",""
"uuid:dd640a1a-7c6c-4161-8428-a92ee7ae474d","http://resolver.tudelft.nl/uuid:dd640a1a-7c6c-4161-8428-a92ee7ae474d","What Does 'Failure' Mean in Civic Tech?: We Need Continued Conversations About Discontinuation","Hamm, Andrea (Weizenbaum Institute for the Networked Society - German Internet Institute); Shibuya, Yuya (University of Tokyo); Cerratto Pargman, Teresa (Stockholm University); Bendor, R. (TU Delft Design Conceptualization and Communication); Raetzsch, Christoph (Aarhus University); Hendawy, Mennatullah (Ain Shams University); Rehak, Rainer (Weizenbaum Institute for the Networked Society - German Internet Institute); Klerks, Gwen (Eindhoven University of Technology); Schouten, Ben (Eindhoven University of Technology); Brodersen Hansen, Nicolai (Aalborg University)","","2024","Civic tech, also referred to as digital civics in HCI, designates efforts to use technology to bring together citizens, bring governments closer to citizens, or improve public service infrastructure. Such sociotechnical encounters are meant to address public needs and increase interactions and information flows between citizens and/or authorities. In this sense, they represent efforts to bolster democratic participation and oversight. Yet, despite the importance of these goals and due to their inherent complexity, civic tech initiatives are often discontinued, leading to a considerable loss of public investment and energy and contributing to a sense of failure. To be sure, this is a global phenomenon: While civic tech initiatives emerge at different places in the world, they are often confronted with the same or very similar impediments. But because of the sense of failure felt by those involved, there are few opportunities to openly discuss discontinuation. Events and academic conferences dedicated to civic tech often foreground short-term success stories and published research papers, and so HCI practitioners and researchers miss opportunities to consider long-term perspectives and slower, ongoing (democratic) transformation processes. What we suggest here, therefore, is that failure and discontinuation should also be seen as productive learning opportunities.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-02","","","Design Conceptualization and Communication","","",""
"uuid:149f61ec-c39d-491a-8313-690d5d77fa1b","http://resolver.tudelft.nl/uuid:149f61ec-c39d-491a-8313-690d5d77fa1b","The Internet of Batteryless Things","Ahmed, Saad (Georgia Institute of Technology); Islam, Bashima (Worcester Polytechnic Institute); Yildirim, Kasim Sinan (Università di Trento); Zimmerling, Marco (Technische Universität Darmstadt); Pawełczak, Przemysław (TU Delft Embedded Systems); Alizai, Muhammad Hamad (Lahore University of Management Sciences); Lucia, Brandon (Carnegie Mellon University); Mottola, Luca (Politecnico di Milano); Sorber, Jacob (Clemson University); Hester, Josiah (Georgia Institute of Technology)","","2024","","","en","journal article","","","","","","","","","","","Embedded Systems","","",""
"uuid:a48c1478-abfd-4fa1-86b0-0b1ddff9a3b6","http://resolver.tudelft.nl/uuid:a48c1478-abfd-4fa1-86b0-0b1ddff9a3b6","Strong invariance principles for ergodic Markov processes","Pengel, A.L. (TU Delft Statistics); Bierkens, G.N.J.C. (TU Delft Statistics)","","2024","Strong invariance principles describe the error term of a Brownian approximation to the partial sums of a stochastic process. While these strong approximation results have many applications, results for continuous-time settings have been limited. In this paper, we obtain strong invariance principles for a broad class of ergodic Markov processes. Strong invariance principles provide a unified framework for analysing commonly used estimators of the asymptotic variance in settings with a dependence structure. We demonstrate how this can be used to analyse the batch means method for simulation output of Piecewise Deterministic Monte Carlo samplers. We also derive a fluctuation result for additive functionals of ergodic diffusions using our strong approximation results.","asymptotic variance estimation; piecewise deterministic Markov processes; Strong invariance principle","en","journal article","","","","","","","","","","","Statistics","","",""
"uuid:37765bba-314a-43f5-a909-2a731e307d70","http://resolver.tudelft.nl/uuid:37765bba-314a-43f5-a909-2a731e307d70","Multi-mode industrial soft sensor method based on mixture Laplace variational auto-encoder","Zhang, Tianming (Taiyuan University of Technology); Yan, Gaowei (Taiyuan University of Technology; Shanxi Research Institute of Huairou Laboratory); Li, Rong (Taiyuan University of Technology); Xiao, Shuyi (Taiyuan University of Technology); Pang, Y. (TU Delft Transport Engineering and Logistics)","","2024","The industrially collected process data usually exhibit non-Gaussian and multi-mode characteristics. Due to sensor failures, irregular disturbances, and transmission problems, there are unavoidable outliers that make the data exhibit heavy-tailed characteristics. To this end, a variational auto-encoder regression method based on the mixture Laplacian distribution (MLVAER) is proposed, by introducing a type-II multivariate Laplacian distribution in the latent variable space for robust modeling, and further extending it to the mixture form to accommodate multi-mode processes, the corresponding reparameterization trick is finally proposed for the mixture form of this distribution for neural network gradient descent training. The model based on this distribution assumption has higher degrees of freedom than the model based on the traditional multivariate Laplace distribution assumption when the network structure is the same. Numerical simulation and experiments on two industrial examples demonstrate that the proposed algorithm reduces the root mean square error by over 15% compared to other algorithms.","Heavy tail; Mixture Laplace; Multi-mode; Soft sensor; Variational auto-encoder","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-05","","","Transport Engineering and Logistics","","",""
"uuid:b582824d-9bc4-4840-8868-bf2e5ce75c50","http://resolver.tudelft.nl/uuid:b582824d-9bc4-4840-8868-bf2e5ce75c50","Ocean Bottom Seismometer Clock Correction using Ambient Seismic Noise","Naranjo, D. (TU Delft Applied Geophysics and Petrophysics; King Abdullah University of Science and Technology); Parisi, Laura (King Abdullah University of Science and Technology); Jónsson, Sigurjón (King Abdullah University of Science and Technology); Jousset, Philippe (Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences); Werthmüller, D. (TU Delft Applied Geophysics and Petrophysics); Weemstra, C. (TU Delft Applied Geophysics and Petrophysics; Royal Netherlands Meteorological Institute (KNMI))","","2024","Ocean-bottom seismometers (OBSs) are equipped with seismic sensors that record acoustic and seismic events at the seafloor, which makes them suitable for investigating tectonic structures capable of generating earthquakes offshore. One critical parameter to obtain accurate earthquake locations is the absolute time of the incoming seismic signals recorded by the OBSs. It is, however, not possible to synchronize the internal clocks of the OBSs with a known reference time, given that GNSS signals are unable to reach the instrument at the sea bottom. To address this issue, here we introduce a new method to synchronize the clocks of large-scale OBS deployments. Our approach relies on the theoretical time-symmetry of time-lapse (averaged) crosscorrelations of ambient seismic noise. Deviations from symmetry are attributed to clock errors. This implies that the recovered clock errors will be obscured by lapse crosscorrelations' deviations from symmetry that are not due to clock errors. Non-uniform surface wave illumination patterns are arguably the most notable source which breaks the time symmetry. Using field data, we demonstrate that the adverse effects of non-uniform illumination patterns on the recovered clock errors can be mitigated by means of a weighted least-squares inversion that is based on station-station distances. In addition, our methodology permits the recovery of timing errors at the time of deployment of the OBSs. This error can be attributed to either: i) a wrong initial time synchronization of the OBS or ii) a timing error induced by changing temperature and pressure conditions while the OBS is sunk to the ocean floor. The methodology is implemented in an open-source Python package named OCloC, and we applied it to the OBS recordings acquired in the context of the IMAGE project in and around Reykjanes, Iceland. As expected, most OBSs suffered from clock drift. Surprisingly, we found incurred timing errors at the time of deployment for most of the OBSs.","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:093c8324-ed84-45f7-a177-daf316d6c5e0","http://resolver.tudelft.nl/uuid:093c8324-ed84-45f7-a177-daf316d6c5e0","Impact of CO2 hydrates on injectivity during CO2 storage in depleted gas fields: A literature review","Aghajanloo, M. (TU Delft Reservoir Engineering); Yan, L. (TU Delft Reservoir Engineering); Berg, Steffen (Shell Global Solutions International B.V.); Voskov, D.V. (TU Delft Reservoir Engineering; Stanford University); Farajzadeh, R. (TU Delft Reservoir Engineering; Shell Global Solutions International B.V.)","","2024","Carbon dioxide capture and storage in subsurface geological formations is a potential solution to limit anthropogenic CO2 emissions and combat global warming. Depleted gas fields offer significant CO2 storage volumes; however, injection of CO2 into these reservoirs poses some potential challenges for the injectivity, containment and well/facility integrity due to low temperatures caused by isenthalpic expansion of CO2. A key injectivity risk is due to possible formation of hydrates at the low expected temperatures. This study aims to address main causes of CO2 hydrate formation and its impact on permeability of porous media. This review highlights the current state of knowledge in the literature while emphasizing the need to bridge existing gaps in derisking CO2 injection into (depleted) low-pressure gas reservoirs. In summary, according to the existing literature, the potential for hydrate formation is assessed to be credible. Current industry solutions exist to manage this risk; however, they are costly and energy intensive. Future research will be needed to provide capabilities to manage this risk more efficiently.","CO hydrate; CO storage; Depleted gas fields; Injectivity; Porous media","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:be561a4b-a184-42ca-a5e1-ff96f5b510bc","http://resolver.tudelft.nl/uuid:be561a4b-a184-42ca-a5e1-ff96f5b510bc","Fatigue behaviour of toe and root stiffener cracks in stiffener-to-deck plate weld of orthotropic bridge decks","Wu, W. (TU Delft Steel & Composite Structures); Veljkovic, M. (TU Delft Steel & Composite Structures); Kolstein, M.H. (TU Delft Steel & Composite Structures); Maljaars, Johan (Eindhoven University of Technology; TNO); Pijpers, Richard (TNO)","","2024","Fatigue cracks in the stiffener-to-deck plate connections of orthotropic bridge decks, initiating from the weld toe or root and propagating into the stiffener or weld throat, are experimentally and numerically studied. A statistical analysis of the structural stress is carried out using the experimental data. Automatic welded specimens show a significantly higher fatigue resistance than manual welded ones for both details of the study. Including results in the literature, the characteristic fatigue resistances appear larger than the values in current standards and range between 100 and 160 MPa. A proposal for the fatigue resistance values is given for design purposes. The effective notch stress, averaged strain energy density factor, and fracture mechanics methods are employed to study the sensitivity of the weld toe and root cracks for different (geometrical) variations, such as the lack of weld penetration. Among them, the fracture mechanics method agrees best with the experimental data. With the increase of weld penetration ratios from 75% to 100%, the fracture mechanics predicted fatigue resistances remain approximately equal for the weld toe cracks and increase for the weld root cracks.","Fatigue resistance; Local assessment methods; Orthotropic bridge deck; Structural stress; Toe and root stiffener cracks","en","journal article","","","","","","","","","","","Steel & Composite Structures","","",""
"uuid:9f9c80c2-a405-491b-b7fd-3b0769f9711d","http://resolver.tudelft.nl/uuid:9f9c80c2-a405-491b-b7fd-3b0769f9711d","Changes in appearance during the spoilage process of fruits and vegetables: Implications for consumer use and disposal","Schifferstein, Hendrik N.J. (TU Delft Design Aesthetics)","","2024","People waste a lot of food, especially at the consumption stage in consumer households. Despite the urgency of this topic, little is known about how consumers use visual inspection to decide to throw away fruits and vegetables at different stages of ripening and spoilage. We presented 366 US consumers with images of a banana, mango, cucumber, and avocado in 5 stages of decay in an online study and we determined how signs of decay affected participants’ consumption, preparation and disposal behaviors. As expected, product attractiveness, freshness, healthiness, and nutritiousness decreased, while the degree of decay, overripeness, and disgust increased over time. The number of people willing to consume the product was linearly related to the perceived proportion of the product affected by decay, while the number of people wanting to cut off bad parts was highest when about 40% of the product was judged to be affected. As time went on, the banana was cooked and mashed more often, while the cucumber was peeled more often. As growing, ripening and decay differ considerably between agricultural products, it is important to take sensory and preparation differences into account when investigating consumption and disposal behaviors.","Decay; Decision making; Food literacy; Food safety; Food waste","en","journal article","","","","","","","","","","","Design Aesthetics","","",""
"uuid:cfcc180e-e253-4c3d-a32c-af6f8ccae757","http://resolver.tudelft.nl/uuid:cfcc180e-e253-4c3d-a32c-af6f8ccae757","Depth of Sudden Velocity Changes Derived From Multi-Mode Rayleigh Waves","Finger, C. (Fraunhofer IEG); Löer, K. (TU Delft Applied Geophysics and Petrophysics; University of Aberdeen)","","2024","To integrate structural subsurface models and smooth seismic velocity models, they need to share common features and resolutions. Here, we propose a new approach, Depth Assessment from Rayleigh Wave Ellipticities (DARE), for estimating the depth of sudden velocity changes from ambient-noise multi-mode Rayleigh waves applicable to a wide range of frequencies. At frequencies where multi-mode Rayleigh waves have an extremum in ellipticity, the phase velocity can be used to estimate the depth of sudden velocity changes. We test our approach theoretically, numerically, and on real data from two geothermal sites by extracting Rayleigh wave ellipticities and phase velocities from three-component beamforming of ambient noise using the python code package B3AMpy. For a small-scale array, our approach validates the depth of quaternary sediments predicted by geological models. For deeper velocity changes, high uncertainties remain but the general trend of inclining boundaries can be recovered well. We demonstrate that, if impedance contrasts are larger than three, our approach is valid for multiple layers, laterally heterogeneous models, and a wide range of Poisson ratios.","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:6fd718ca-f688-48ad-b4e0-023f9edf1731","http://resolver.tudelft.nl/uuid:6fd718ca-f688-48ad-b4e0-023f9edf1731","To warrant clinical adoption AI models require a multi-faceted implementation evaluation","van de Sande, Davy (Erasmus MC); Chung, Eline Fung Fen (Erasmus MC); Oosterhoff, J.H.F. (TU Delft Information and Communication Technology); van Bommel, Jasper (Erasmus MC); Gommers, D.A.M.P.J. (Erasmus MC); van Genderen, Michel E. (Erasmus MC)","","2024","Despite artificial intelligence (AI) technology progresses at unprecedented rate, our ability to translate these advancements into clinical value and adoption at the bedside remains comparatively limited. This paper reviews the current use of implementation outcomes in randomized controlled trials evaluating AI-based clinical decision support and found limited adoption. To advance trust and clinical adoption of AI, there is a need to bridge the gap between traditional quantitative metrics and implementation outcomes to better grasp the reasons behind the success or failure of AI systems and improve their translation into clinical value.","","en","journal article","","","","","","","","","","","Information and Communication Technology","","",""
"uuid:eb309ec5-ef4f-4136-be44-fffde25b3506","http://resolver.tudelft.nl/uuid:eb309ec5-ef4f-4136-be44-fffde25b3506","User experience of wearing comfort of reusable versus disposable surgical gowns and environmental perspectives: A cross-sectional survey","van Nieuwenhuizen, Kim E. (Leiden University Medical Center); Friedericy, Hans J. (Leiden University Medical Center); van der Linden, Sjaak (Leiden University Medical Center); Jansen, F.W. (TU Delft Medical Instruments & Bio-Inspired Technology; Leiden University Medical Center); van der Eijk, A.C. (TU Delft Medical Instruments & Bio-Inspired Technology; Leiden University Medical Center)","","2024","Objective: To determine the user experience of wearing comfort of reusable sterile surgical gowns and compare these gowns with conventional disposable surgical gowns. Design: Cross-sectional survey. Setting: An academic hospital in the Netherlands. Population: Gynaecologists, surgeons, residents and operating room assistants (n=80). Methods: Quantitative and qualitative data were obtained via a written questionnaire. Participants provided subjective comments and scored the reusable gown on each individual topic with a score from 1 to 5 (1 = unsatisfactory, 2 = moderate, 3 = good, 4 = very good, 5 = excellent) and compared the reusable gown with the conventional disposable alternative (better, equal or worse). Main outcome measures: Wearing comfort: ventilation and temperature regulation, fit and length, functionality, barrier function and ease of use. Results: The results of the overall scores of the reusable gown are scored as ‘very good’ (mean 4.3, SD ± 0.5) by its users. Regarding comparison of the gowns, more than 79% (lowest score 79%, highest score 95%) of the participants scored the reusable gown equal or higher on six of seven topics. The topic ‘ease of use’ was scored equal or higher by 59% of the participants. Subjective comments provided information on possible improvements. Conclusions: The findings of this study demonstrate that there is professional acceptance regarding the utilisation of reusable surgical gowns. To facilitate broader adoption, it is imperative to foster collaboration among suppliers and healthcare institutions. The reusable surgical gown is an environmentally sustainable, safe and comfortable alternative in the operating room.","climate change; comfort; operating room; surgery; surgical gowns; sustainability; user experience","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:73cd9700-c88a-472c-b241-247fb1dab4cc","http://resolver.tudelft.nl/uuid:73cd9700-c88a-472c-b241-247fb1dab4cc","Correction: The stories about racism and health: the development of a framework for racism narratives in medical literature using a computational grounded theory approach","Figueroa, C.A. (TU Delft Information and Communication Technology; University of California); Manalo-Pedro, Erin (University of California); Pola, Swetha (University of California); Darwish, Sajia (University of California); Sachdeva, Pratik (University of California); Guerrero, Christian (American Medical Association); von Vacano, Claudia (University of California); Jha, Maithili (American Medical Association); De Maio, Fernando (DePaul University); Kennedy, Chris J. (University of California; Harvard Medical School; Massachusetts General Hospital)","","2024","After publication of this article [1], the authors reported that the disclaimer statement in the backmatter was missing and should have read ‘Disclaimer: The ideas in this article are those of the authors and do not necessarily represent policy of the American Medical Association.’ The original article [1] has been corrected.
(International Journal for Equity in Health, (2023), 22, 1, (265), 10.1186/s12939-023-02077-0)
2) storage potential to support an H2-based energy future. Understanding H2 flow and trapping in subsurface rocks is crucial to reliably evaluate their storage efficiency. In this work, we perform cyclic H2 flow visualization experiments on a layered rock sample with varying pore and throat sizes. During drainage, H2 follows a path consisting of large pores and throats, through a low permeability rock layer, substantially reducing H2 storage capacity. Moreover, due to the rock heterogeneity and depending on the experimental flow strategy, imbibition unexpectedly results in higher H2 saturation compared to drainage. These results emphasize that small-scale rock heterogeneity, which is often unaccounted for in reservoir-scale models, plays a vital role in H2 displacement and trapping in subsurface porous media, with implications for efficient storage strategies.","Energy transition; Hydrogen storage; Pore-scale 3D visualization; Porous media","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:6a4c6bc2-1106-490d-b6c0-1f4e33b838d5","http://resolver.tudelft.nl/uuid:6a4c6bc2-1106-490d-b6c0-1f4e33b838d5","Forecasting House Prices through Credit Conditions: A Bayesian Approach","van der Drift, R. (TU Delft Real Estate Management); de Haan, J. (TU Delft Real Estate Management); Boelhouwer, P.J. (TU Delft Real Estate Management)","","2024","As housing development and housing market policies involve many long-term decisions, improving house price predictions could benefit the functioning of the housing market. Therefore, in this paper, we investigate how house price predictions can be improved. In particular, the merits of Bayesian estimation techniques in enhancing house price predictions are examined in this study. We compare the pseudo out-of-sample forecasting power of three Bayesian models—a Bayesian vector autoregression in levels (BVAR-l), a Bayesian vector autoregression in differences (BVAR-d), and a Bayesian vector error correction model (BVECM)—and their non-Bayesian counterparts. These techniques are compared using a theoretical model that predicts the borrowing capacity of credit-constrained and unconstrained households to affect house prices. The findings indicate that the Bayesian models outperform their non-Bayesian counterparts, and within the class of Bayesian models, the BVAR-d is found to be more accurate than the BVAR-l. For the two winning Bayesian models, i.e., the BVECM and the BVAR-d, the difference in forecasting power is more ambiguous; which model prevails depends on the desired forecasting horizon and the state of the economy. Hence, both Bayesian models may be considered when conducting research on house prices.","Bayesian VAR; Bayesian VECM; Cointegration; Forecasting; House prices","en","journal article","","","","","","","","","","","Real Estate Management","","",""
"uuid:ce82c956-9af7-45be-9312-6509922b4f13","http://resolver.tudelft.nl/uuid:ce82c956-9af7-45be-9312-6509922b4f13","The influence of spatial variation on the design of foundations of immersed tunnels: Advanced probabilistic analysis","'t Hart, C.M.P. (TU Delft Hydraulic Structures and Flood Risk; Tunnel Engineering Consultants; Royal Haskoning DHV); Morales Napoles, O. (TU Delft Hydraulic Structures and Flood Risk); Jonkman, Sebastiaan N. (TU Delft Hydraulic Structures and Flood Risk)","","2024","Immersed tunnels are positive buoyant structures during installation and negative buoyant after installation. A tunnel is composed of sequential immersed elements that are coupled to each other in joints. Tunnel elements consist of segments which are compressed to each other by longitudinal post-tensioning. After immersion the tunnel is supported by the seabed and the longitudinal post-tension is cut at the joints between segments. Therefore, the structure is a segmented lining which is sensitive for settlements due to non uniform circumstances over the length of the tunnel. An uneven response of the bedding underneath the tunnel introduce shear forces in joints of an immersed tunnel. Because immersed tunnels need to be buoyant during installation, they have limitations on weight and geometry, the size and therefore the capacity of these shear keys is limited because the height of the tunnel, as shear keys are applied in the walls of the tunnel. The foundation response is influenced by many factors related to subsoil but also to construction and dredging tolerances. The shear forces were derived as a function of different covariance lengths for subsoil stiffness and dredging tolerances for different tunnel layouts. In reliability analyses, using two different probabilistic methods, exceedance probabilities of maximum shear forces are derived for one lay out using Non Parametric Bayesian Networks and Vine Copulas. The analyses give more insight in to the magnitude of the shear forces in joints both in conditioned and unconditioned situations and this can be used for the design of immersed tunnels.","Bedding; Covariance length; Dredging; Gaussian random fields; Immersed tunnels; Non Parametric Bayesian Network; Soft soil tunnels; Vine Copulas","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:96f83610-4736-4d77-9be1-1b617a7ac7bc","http://resolver.tudelft.nl/uuid:96f83610-4736-4d77-9be1-1b617a7ac7bc","Characterisation of bacterial decay effects on wooden foundation piles across various historical periods","Mirra, M. (TU Delft Bio-based Structures & Materials); Pagella, G. (TU Delft Bio-based Structures & Materials); Lee, Michael (Student TU Delft); Gard, W.F. (TU Delft Bio-based Structures & Materials); Ravenshorst, G.J.P. (TU Delft Bio-based Structures & Materials); van de Kuilen, J.W.G. (TU Delft Bio-based Structures & Materials; Technische Universität München)","","2024","In the historic city centre of Amsterdam (NL), the predominant foundation system is comprised of wooden piles. Due to their placement below the water table, these foundations are susceptible to bacterial decay. This study aims to investigate and compare various methods for characterizing decay patterns within the cross sections of piles retrieved from two bridges in Amsterdam. The examined piles span different construction years: three originate from 1727, four from 1886, and two from 1922. Following extraction, the piles were transported to TU Delft Stevin II Laboratory, where they underwent further subdivision into three segments, each representing the head, middle, and tip, resulting in a total of 27 segments. The effects of bacterial decay were characterised by performing micro-drilling measurements, small-scale material and compressive tests on prismatic samples extracted from the segments' cross sections, computed tomography scans, and light microscopy observations. Microscopic examination revealed severe degradation in all segments dating back to 1727, extending 20–50 mm from their surface. This outcome was also confirmed by the other adopted methods: the corresponding prisms had large moisture contents and poor mechanical properties, while low basic densities and drilling amplitudes were obtained from CT scans and micro-drilling measurements, respectively. On the contrary, the internal sections of the 1727 segments exhibited no evidence of decay and demonstrated properties consistent with those observed in sound segments from 1886 and 1922. Finally, the observed gradients of density, strength, and stiffness were well correlated with micro-drilling measurements, which can therefore be reliably used as on-site assessment method to reconstruct the properties of the piles.","Bacterial decay; Conservation of architectural heritage; Micro-drilling techniques; Service life modelling; Wooden foundation piles","en","journal article","","","","","","","","","","","Bio-based Structures & Materials","","",""
"uuid:86377084-00c8-4888-a55d-3c433a016262","http://resolver.tudelft.nl/uuid:86377084-00c8-4888-a55d-3c433a016262","Liquid injectivity in a SAG foam process: Effect of permeability","Gong, J. (TU Delft Reservoir Engineering; Hohai University); Wang, Yuan (Hohai University); Kamarul Bahrim, Ridhwan Zhafri B. (Petronas Research); Tewari, Raj Deo (Petronas Research); Mahamad Amir, Mohammad Iqbal (Petronas Research); Farajzadeh, R. (TU Delft Reservoir Engineering; Shell Global Solutions International B.V.); Rossen, W.R. (TU Delft Reservoir Engineering)","","2024","Foam is utilized in enhanced oil recovery and CO2 sequestration. Surfactant-alternating-gas (SAG) is a preferred approach for placing foam into reservoirs, due to it enhances gas injection and minimizes corrosion in facilities. Our previous studies with similar permeability cores show that during SAG injection, several banks occupy the area near the well where fluid exhibits distinct behaviour. However, underground reservoirs are heterogeneous, often layered. It is crucial to understand the effect of permeability on fluid behaviour and injectivity in a SAG process. In this work, coreflood experiments are conducted in cores with permeabilities ranging from 16 to 2300 mD. We observe the same sequence of banks in cores with different permeabilities. However, the speed at which banks propagate and their overall mobility can vary depending on permeability. At higher permeabilities, the gas-dissolution bank and the forced-imbibition bank progress more rapidly during liquid injection. The total mobilities of both banks decrease with permeability. By utilizing a bank-propagation model, we scale up our experimental findings and compare them to results obtained using the Peaceman equation. Our findings reveal that the liquid injectivity in a SAG foam process is misestimated by conventional simulators based on the Peaceman equation. The lower the formation permeability, the greater the error.","Enhanced oil recovery; Foam; Injectivity; Permeability; Surfactant-alternating-gas","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:b2d6fbf3-30ca-4275-94fe-563842330707","http://resolver.tudelft.nl/uuid:b2d6fbf3-30ca-4275-94fe-563842330707","Beyond Failure and Success: A Process View on Imperfect Projects as Common Practice","van Marrewijk, A.H. (TU Delft Design & Construction Management; BI Norwegian Business School; Vrije Universiteit Amsterdam); Stjerne, Iben (Technical University of Denmark); Sydow, Jörg (Freie Universität Berlin)","","2024","This editorial scrutinizes the dichotomy of a project’s success and failure, which, in our opinion is too rigid, inflexible, and unnuanced. The aim of this special issue is to nuance this dichotomy by moving toward a process view on how imperfection is brought about in projects. We introduce and discuss five topics important for such a process view: (1) improvisation, (2) temporality, (3) power and politics, (4) transition, and (5) intentionality. We argue that a holistic, processual view of imperfections premises emergence and continuous learning and judgments of the project both in and over time. All five articles in this special issue deal with at least one of the discussed themes of our proposed process view on imperfect projects.","failure; imperfect project; learning; process; success","en","contribution to periodical","","","","","","","","","","","Design & Construction Management","","",""
"uuid:a097ae29-f9c3-4629-87f0-49c037cdec52","http://resolver.tudelft.nl/uuid:a097ae29-f9c3-4629-87f0-49c037cdec52","From Short Circuit to Completed Circuit: Conductive Hydrogel Facilitating Oral Wound Healing","Zhou, Qiangqiang (Fudan University); Dai, Hanqing (Fudan University); Yan, Yukun (Fudan University); Qin, Zhiming (Fudan University); Zhou, Mengqi (Fudan University); Zhang, Wanlu (Fudan University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Guo, Ruiqian (Fudan University); Wei, X. (Fudan University)","","2024","The primary challenges posed by oral mucosal diseases are their high incidence and the difficulty in managing symptoms. Inspired by the ability of bioelectricity to activate cells, accelerate metabolism, and enhance immunity, a conductive polyacrylamide/sodium alginate crosslinked hydrogel composite containing reduced graphene oxide (PAA-SA@rGO) is developed. This composite possesses antibacterial, anti-inflammatory, and antioxidant properties, serving as a bridge to turn the “short circuit” of the injured site into a “completed circuit,” thereby prompting fibroblasts in proximity to the wound site to secrete growth factors and expedite tissue regeneration. Simultaneously, the PAA-SA@rGO hydrogel effectively seals wounds to form a barrier, exhibits antibacterial and anti-inflammatory properties, and prevents foreign bacterial invasion. As the electric field of the wound is rebuilt and repaired by the PAA-SA@rGO hydrogel, a 5 × 5 mm2 wound in the full-thickness buccal mucosa of rats can be expeditiously mended within mere 7 days. The theoretical calculations indicate that the PAA-SA@rGO hydrogel can aggregate and express SOX2, PITX1, and PITX2 at the wound site, which has a promoting effect on rapid wound healing. Importantly, this PAA-SA@rGO hydrogel has a fast curative effect and only needs to be applied for the first three days, which significantly improves patient satisfaction during treatment.","conductive hydrogel; microphysiological electric field; oral mucosal disease; tissue regeneration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-02","","","Electronic Components, Technology and Materials","","",""
"uuid:8928e27d-d3b4-409a-99a2-20c5c53208e0","http://resolver.tudelft.nl/uuid:8928e27d-d3b4-409a-99a2-20c5c53208e0","Natronoglomus mannanivorans gen. nov., sp. nov., beta-1,4-mannan utilizing natronoarchaea from hypersaline soda lakes","Sorokin, Dimitry Y. (TU Delft BT/Environmental Biotechnology; Russian Academy of Sciences); Elcheninov, Alexander G. (Russian Academy of Sciences); Bale, Nicol J. (NIOZ Royal Netherlands Institute for Sea Research); Sinnighe Damsté, Jaap S. (NIOZ Royal Netherlands Institute for Sea Research); Kublanov, Ilya V. (Russian Academy of Sciences)","","2024","Beta-mannans are insoluble plant polysaccharides with beta-1,4-linked mannose as the backbone. We used three forms of this polysaccharide, namely, pure mannan, glucomannan, and galactomannan, to enrich haloarchaea, which have the ability to utilize mannans for growth. Four mannan-utilizing strains obtained in pure cultures were closely related to each other on the level of the same species. Furthermore, another strain selected from the same habitats with a soluble beta-1,4-glucan (xyloglucan) was also able to grow with mannan. The
phylogenomic analysis placed the isolates into a separate lineage of the new genus level within the family Natrialbaceae of the class Halobacteria. The strains are moderate alkaliphiles, extremely halophilic, and aerobic saccharolytics. In addition to the three beta-mannan forms, they can also grow with cellulose, xylan, and xyloglucan. Functional genome analysis of two representative strains demonstrated the presence of several genes coding for extracellular endo-beta-1,4-mannanase from the GH5_7 and 5_8 subfamilies and the GH26 family of glycosyl hydrolases. Furthermore, a large spectrum of genes encoding other glycoside hydrolases that were potentially involved in the hydrolysis of cellulose and xylan were also identified in the genomes. A comparative genomics analysis also showed the presence of similar endo-beta-1,4-mannanase homologs in the cellulotrophic genera Natronobiforma and Halococcoides. Based on the unique physiological properties and the results of phylogenomic analysis, the novel mannan-utilizing halolarchaea are proposed to be classified into a new genus and species Natronoglomus mannanivorans gen. nov., sp. nov. with the type strain AArc-m2/3/4 (=JCM 34861=UQM 41565).","Hypersaline lakes; haloarchaea; glucomannan; galactomannan; beta-1,4-mannan","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:e84e88ef-7994-413c-a273-24ad4dd24d40","http://resolver.tudelft.nl/uuid:e84e88ef-7994-413c-a273-24ad4dd24d40","Genome-wide characterization of circulating metabolic biomarkers","Karjalainen, Minna K. (University of Oulu); Karthikeyan, Savita (University of Cambridge); Oliver-Williams, Clare (University of Cambridge); Sliz, Eeva (University of Oulu); Allara, Elias (University of Cambridge); Fung, Wing Tung (University of Cambridge); Surendran, Praveen (University of Cambridge); van den Akker, E.B. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center)","","2024","Genome-wide association analyses using high-throughput metabolomics platforms have led to novel insights into the biology of human metabolism1–7. This detailed knowledge of the genetic determinants of systemic metabolism has been pivotal for uncovering how genetic pathways influence biological mechanisms and complex diseases8–11. Here we present a genome-wide association study for 233 circulating metabolic traits quantified by nuclear magnetic resonance spectroscopy in up to 136,016 participants from 33 cohorts. We identify more than 400 independent loci and assign probable causal genes at two-thirds of these using manual curation of plausible biological candidates. We highlight the importance of sample and participant characteristics that can have significant effects on genetic associations. We use detailed metabolic profiling of lipoprotein- and lipid-associated variants to better characterize how known lipid loci and novel loci affect lipoprotein metabolism at a granular level. We demonstrate the translational utility of comprehensively phenotyped molecular data, characterizing the metabolic associations of intrahepatic cholestasis of pregnancy. Finally, we observe substantial genetic pleiotropy for multiple metabolic pathways and illustrate the importance of careful instrument selection in Mendelian randomization analysis, revealing a putative causal relationship between acetone and hypertension. Our publicly available results provide a foundational resource for the community to examine the role of metabolism across diverse diseases.","","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:c52e6616-3284-45c8-9577-7e92be7c49a9","http://resolver.tudelft.nl/uuid:c52e6616-3284-45c8-9577-7e92be7c49a9","Examining student profiles for dealing with wickedness","Veltman, M.M. (Universiteit van Amsterdam; Windesheim University of Applied Sciences); van Keulen, J. (TU Delft Science Education and Communication); Smits, A. E.H. (Windesheim University of Applied Sciences); Voogt, J. M. (Universiteit van Amsterdam)","","2024","When addressing problems with wicked tendencies in higher professional education, students experience complexity, uncertainty, and value divergence. Furthermore, they are confronted with disciplinary, organisational, and sector boundaries. Prior research has revealed variability in students’ experiences and boundary-crossing behaviour when dealing with problems with wicked tendencies. In this study we explore these differences by identifying student profiles based on the attributes that comprise the competence for dealing with problems with wicked tendencies, and by identifying their relations with students’ boundary-crossing behaviour and relevant work experience. Person-centred cluster analysis in a sample of first-year students (N = 264) from a bachelor’s programme in social work identified four student profiles, based on students’ self-assessed degree of creativity, critical thinking, initiative, proactivity, risk tolerance, and work efficacy. Meaningful relations with students’ prior work experiences and their boundary-crossing behaviour were found. These profiles could serve to better understand students’ boundary-crossing behaviour when confronted with problems with wicked tendencies, and help teachers foster the development of all students.","boundary crossing; higher education; problem-solving competence; student profiles; teacher strategies; wicked problems","en","journal article","","","","","","","","","","","Science Education and Communication","","",""
"uuid:53403207-3875-4e99-a6f0-f7128f60e942","http://resolver.tudelft.nl/uuid:53403207-3875-4e99-a6f0-f7128f60e942","Moral foundations in gender violence cases decided in Portuguese courts","Martins Martinho Bessa, A.C. (TU Delft Transport and Logistics); Kroesen, M. (TU Delft Transport and Logistics); Chorus, C.G. (TU Delft Industrial Design Engineering)","","2024","Gender violence encompasses a multitude of morally problematic psychological, physical, and sexual behaviors that, in most countries, constitute criminal offenses. In this study, we investigate the association between moral foundations (Care, Fairness, Loyalty, Authority, and Sanctity) and punitive responses to gender violence offenses. Our case study focuses on gender violence in Portugal, a country in which these offenses are a prevalent social problem. We collected data on gender violence legal cases decided in Portuguese courts between 2002 and 2022, and we used a latent class cluster analysis model to identify the complex patterns in the data and reduce such patterns to a distinct number of clusters. Four main clusters unravel latent relations between the foundations mapped in the legal narratives and corresponding punitive responses: (i) Affirmative with suspended prison time (moral rhetoric rooted in Authority); (ii) Mixed outcomes but no prison time (moral rhetoric rooted in Sanctity); (iii) Affirmative with lengthy prison time large compensation (moral rhetoric rooted in Loyalty and Care); and (iv) Affirmative with court fines (moral rhetoric rooted in Fairness). The moral foundations provide a valuable lens to understand the problem of gender violence, but further research is needed to establish the causal mechanisms between morality and punitive responses to gender violence.","Court; domestic violence; gender violence; latent class cluster analysis; legal cases; moral foundations theory; morality","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-05","Industrial Design Engineering","","Transport and Logistics","","",""
"uuid:a7c6a5cf-825f-4565-a32d-a56b60326e39","http://resolver.tudelft.nl/uuid:a7c6a5cf-825f-4565-a32d-a56b60326e39","Preface","Camara, Oscar (Pompeu Fabra University); Puyol-Antón, Esther (King’s College London); Sermesant, Maxime (Inria); Suinesiaputra, Avan (King’s College London); Tao, Q. (TU Delft ImPhys/Tao group); Wang, Chengyan (Fudan University); Young, Alistair (King’s College London)","","2024","","","en","contribution to periodical","","","","","","","","","","","ImPhys/Tao group","","",""
"uuid:dafbd1f9-d043-4b34-b0ed-a3a6461d5ee1","http://resolver.tudelft.nl/uuid:dafbd1f9-d043-4b34-b0ed-a3a6461d5ee1","Bayesian Linear Inverse Problems in Regularity Scales with Discrete Observations","Yan, Dong (Student TU Delft); Gugushvili, Shota (Wageningen University & Research); van der Vaart, A.W. (TU Delft Statistics)","","2024","We obtain rates of contraction of posterior distributions in inverse problems with discrete observations. In a general setting of smoothness scales we derive abstract results for general priors, with contraction rates determined by discrete Galerkin approximation. The rate depends on the amount of prior concentration near the true function and the prior mass of functions with inferior Galerkin approximation. We apply the general result to non-conjugate series priors, showing that these priors give near optimal and adaptive recovery in some generality, Gaussian priors, and mixtures of Gaussian priors, where the latter are also shown to be near optimal and adaptive.","35R30; 62G20; Adaptive estimation; Fixed design; Galerkin; Gaussian prior; Hilbert scale; Interpolation; Linear inverse problem; Nonparametric Bayesian estimation; Posterior contraction rate; Random series prior; Regression; Regularity scale","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-07","","","Statistics","","",""
"uuid:044f3dff-d554-4635-8e7f-775f23bbcea0","http://resolver.tudelft.nl/uuid:044f3dff-d554-4635-8e7f-775f23bbcea0","Editorial - Human-Like Locomotion and Manipulation: Current Achievements and Challenges (Part I)","Li, Qiang (Shenzhen Technology University); Li, Gaofeng (Zhejiang University); Yu, Chuang (The University of Manchester); Luo, Shan (King’s College London); Ding, J. (TU Delft Learning & Autonomous Control)","","2024","","","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-29","","","Learning & Autonomous Control","","",""
"uuid:c86fc708-a912-4105-a684-2b660ed119fe","http://resolver.tudelft.nl/uuid:c86fc708-a912-4105-a684-2b660ed119fe","Towards Automatic Principles of Persuasion Detection Using Machine Learning Approach","Bustio-Martínez, Lázaro (Universidad Iberoamericana); Herrera-Semenets, Vitali (Centro de Aplicaciones de Tecnologías de Avanzada); García-Mendoza, Juan-Luis (Université Sorbonne Paris Nord); González-Ordiano, Jorge Ángel (Universidad Iberoamericana); Zúñiga-Morales, Luis (Universidad Iberoamericana); Sánchez Rivero, Rubén (Centro de Aplicaciones de Tecnologías de Avanzada); Quiróz-Ibarra, José Emilio (Universidad Iberoamericana); Santander-Molina, Pedro Antonio (Pontificia Universidad Católica de Valparaíso); van den Berg, Jan (TU Delft Cyber Security); Buscaldi, Davide (Université Sorbonne Paris Nord)","Hernández Heredia, Yanio (editor); Milián Núñez, Vladimir (editor); Ruiz Shulcloper, José (editor)","2024","Persuasion is a human activity of influence. In marketing, persuasion can help customers find solutions to their problems, make informed choices, or convince someone to buy a useful (or useless) product or service. In computer crimes, persuasion can trick users into revealing sensitive information, or even performing actions that benefit attackers. Phishing is one of the most common and dangerous forms of persuasion-based attacks, as it exploits human vulnerabilities rather than technical ones. Therefore, an intelligent system capable of detecting and classifying persuasion attempts might be useful in protecting users. In this work, an approach that uses Machine Learning to analyze messages based on principles of persuasion and different data representations is presented. The aim of this research is to detect which data representation and which classification algorithm obtain the best results in detecting each principle of persuasion as a prior step to detecting phishing attacks. The results obtained indicate that among the combinations tested, there is one combination of data representation and classification algorithm that performs best. The related classification models obtained can detect the principles of persuasion at a rate that varies between 0.78 and 0.86 of AUC-ROC.","Principles of Persuasion; Machine Learning; Artificial Intelligence; Data representation; Phishing detection","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-20","","","Cyber Security","","",""
"uuid:984278af-7a31-498b-9768-0af914f606f1","http://resolver.tudelft.nl/uuid:984278af-7a31-498b-9768-0af914f606f1","Laminar-Turbulent Transition in Swept-Wing Flows with a Supercritical Forward-Facing Step","Casacuberta Puig, J. (TU Delft Aerodynamics); Hickel, S. (TU Delft Aerodynamics); Kotsonis, M. (TU Delft Aerodynamics)","","2024","Achieving and maintaining laminar flow on large swept lifting surfaces of subsonic aircraft poses a considerable challenge.","","en","book chapter","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-03","","","Aerodynamics","","",""
"uuid:af116b35-92be-4924-b28e-2d1d83f3e4c7","http://resolver.tudelft.nl/uuid:af116b35-92be-4924-b28e-2d1d83f3e4c7","Ultralight Membrane Structures Toward a Sustainable Environment","Comitti, Alessandro (University College London (UCL); CAEMate s.r.l.); Vijayakumaran, H. (TU Delft Team Marcel Sluiter); Nejabatmeimandi, Mohammad Hosein (Tensys Ltd.); Seixas, Luis (University College London (UCL); CAEMate s.r.l.); Cabello, Adrian (Tensys Ltd.); Misseroni, Diego (Università di Trento); Penasa, Massimo (CAEMate s.r.l.); Paech, Christoph (sbp – schlaich bergermann partner); Bessa, M.A. (Brown University)","Bahrami, Alireza (editor)","2024","The building construction industry is the largest anthropogenic source of pollution, with massive energy consumption and substantial CO2 emissions. Lightweight tension structures allow the simultaneous implementation of several sustainable strategies by using recyclable low-carbon structural membranes offering a greener alternative to glass and other cladding materials. Their efficient structural load-bearing mechanisms result in significant weight savings in buildings and a drastic reduction of the environmental impact associated with material production, transportation, use, and disposal. A subgroup of lightweight materials, structural fabrics, and foils has been gaining popularity among designers and architects in recent years because of their desirable features such as high stiffness, strength, ductility, durability, and functional properties. While these structural membranes open new crucial perspectives for the clean energy transition and have been recently employed worldwide, their full potential is still limited by the lack of construction codes, advanced optimization tools, and comprehensive viscous-thermo-mechanical constitutive models. This chapter aims to foster the design of membrane structures by presenting their basic principles and recent advancements in the field. It covers the design approaches, employed materials and efforts in their characterization and modeling, implications on the sustainability of the built environment, current challenges, and future pathways from both academic research and engineering design viewpoints.","Sustainable construction; Lightweight structures; Tension structures; Strucutral optimization; Structural membranes; Membrane engineering","en","book chapter","Springer","","","","","","","","","","Team Marcel Sluiter","","",""
"uuid:b75cb7d3-e850-414b-b4f0-b17a2ae3edf0","http://resolver.tudelft.nl/uuid:b75cb7d3-e850-414b-b4f0-b17a2ae3edf0","Extended Reality as a Catalyst for Circular Economy Transition in the Built Environment","Soman, R. K. (TU Delft Integral Design & Management); Nikolić, D. (University of Reading); Sanchez, B. (Appalachian State University)","De Wolf, Catherine (editor); Çetin, Sultan (editor); Bocken, Nancy (editor)","2024","Extended reality (XR) technologies refer to mixed reality and virtual reality configurations that augment real or represent fully virtual information in an intuitive and immersive manner, transforming the way we plan, design, construct, and operate built environment assets. XR offers great potential to support and accelerate the transition of built environment practices to a circular economy by supporting decisions based on narrow, slow, close, and regenerate strategies. Narrow strategies use XR to simulate the building process to identify potential issues, reduce material waste, and avoid costly mistakes. Slow strategies use XR to enable construction with durable materials and designing for adaptability to extend the lifespan of buildings. Close strategies use XR to facilitate material recovery and support repurposing and reuse, thus reducing waste. Regenerate strategies use XR as a motivational tool to engage citizens, communities, and professionals in design and management decisions. However, applying XR is not without challenges, including technical and process-related limitations, potential misuse, and a lack of rich digital twins. Future research opportunities include the development of rich and accurate digital twins, ethical and sustainable use of XR technologies, and overcoming technical and logistical challenges through interdisciplinary collaboration and user-friendly and accessible XR hardware and software.","extended reality (XR); mixed reality (MR); virtual reality (VR); immersive experiences; built environment; circular economy; digital twins","en","book chapter","Springer","","","","","","","","","","Integral Design & Management","","",""
"uuid:f0f80eaa-0a47-4ca6-a707-4f0a285a2805","http://resolver.tudelft.nl/uuid:f0f80eaa-0a47-4ca6-a707-4f0a285a2805","Exploring Artificial Intelligence for Advancing Performance Processes and Events in Io3MT","Vieira, Romulo (Universidade Federal Fluminense); Muchaluat-Saade, Debora (Universidade Federal Fluminense); Cesar, Pablo (TU Delft Multimedia Computing; Centrum Wiskunde & Informatica (CWI))","Rudinac, Stevan (editor); Worring, Marcel (editor); Liem, Cynthia (editor); Hanjalic, Alan (editor); Jónsson, Björn Pór (editor); Yamakata, Yoko (editor); Liu, Bei (editor)","2024","The Internet of Multisensory, Multimedia and Musical Things (Io3MT) is a new concept that arises from the confluence of several areas of computer science, arts, and humanities, with the objective of grouping in a single place devices and data that explore the five human senses, besides multimedia aspects and music content. In the context of this brave new idea paper, we advance the proposition of a theoretical alignment between the emerging domain in question and the field of Artificial Intelligence (AI). The main goal of this endeavor is to tentatively delineate the inceptive trends and conceivable consequences stemming from the fusion of these domains within the sphere of artistic presentations. Our comprehensive analysis spans a spectrum of dimensions, encompassing the automated generation of multimedia content, the real-time extraction of sensory effects, and post-performance analytical strategies. In this manner, artists are equipped with quantitative metrics that can be employed to enhance future artistic performances. We assert that this cooperative amalgamation has the potential to serve as a conduit for optimizing the creative capabilities of stakeholders.","Artificial Intelligence; Internet of Multisensory; Multimedia and Musical Things; Networked Performances","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-29","","","Multimedia Computing","","",""
"uuid:3c4e3e23-f4bc-44fe-b737-ce1e0fcdfed0","http://resolver.tudelft.nl/uuid:3c4e3e23-f4bc-44fe-b737-ce1e0fcdfed0","Towards Cross-Modal Point Cloud Retrieval for Indoor Scenes","Yu, Fuyang (Beihang University); Wang, Zhen (Tokyo Institute of Technology); Li, Dongyuan (Tokyo Institute of Technology); Zhu, P. (TU Delft Web Information Systems); Liang, Xiaohui (Beihang University); Wang, Xiaochuan (Beijing Technology and Business University); Okumura, Manabu (Tokyo Institute of Technology)","Rudinac, Stevan (editor); Worring, Marcel (editor); Liem, Cynthia (editor); Hanjalic, Alan (editor); Jónsson, Björn Pór (editor); Yamakata, Yoko (editor); Liu, Bei (editor)","2024","Cross-modal retrieval, as an important emerging foundational information retrieval task, benefits from recent advances in multimodal technologies. However, current cross-modal retrieval methods mainly focus on the interaction between textual information and 2D images, lacking research on 3D data, especially point clouds at scene level, despite the increasing role point clouds play in daily life. Therefore, in this paper, we proposed a cross-modal point cloud retrieval benchmark that focuses on using text or images to retrieve point clouds of indoor scenes. Given the high cost of obtaining point cloud compared to text and images, we first designed a pipeline to automatically generate a large number of indoor scenes and their corresponding scene graphs. Based on this pipeline, we collected a balanced dataset called CRISP, which contains 10K point cloud scenes along with their corresponding scene images and descriptions. We then used state-of-the-art models to design baseline methods on CRISP. Our experiments demonstrated that point cloud retrieval accuracy is much lower than cross-modal retrieval of 2D images, especially for textual queries. Furthermore, we proposed ModalBlender, a tri-modal framework which can greatly improve the Text-PointCloud retrieval performance. Through extensive experiments, CRISP proved to be a valuable dataset and worth researching. (Dataset can be downloaded at https://github.com/CRISPdataset/CRISP.)","Cross-modal Retrieval; Indoor Scene; Point Cloud","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-29","","","Web Information Systems","","",""
"uuid:a677328b-f0f2-4deb-8cfb-c5af678770c9","http://resolver.tudelft.nl/uuid:a677328b-f0f2-4deb-8cfb-c5af678770c9","Aircraft Cruise Alternative Trajectories Generation: A Mixed RRG-Clustering Approach","Lebègue, J. (Sopra Steria; Ecole Nationale de L’Aviation Civile); Guitart, Andréas (Ecole Nationale de L’Aviation Civile); Demouge, Céline (Ecole Nationale de L’Aviation Civile); Delahaye, Daniel (Ecole Nationale de L’Aviation Civile); Hoekstra, J.M. (TU Delft Control & Simulation); Feron, Eric (King Abdullah University of Science and Technology)","Martins, Ana Lucia (editor); Ferreira, Joao C. (editor); Kocian, Alexander (editor); Tokkozhina, Ulpan (editor); Helgheim, Berit Irene (editor); Bråthen, Svein (editor)","2024","Weather obstacles in the airspace can interfere with an aircraft’s flight plan. Pilots, assisted by air traffic controllers (ATCs), perform avoidance maneuvers that can be optimized. This paper addresses the generation of alternative aircraft trajectories to resolve unexpected events. The authors propose a solution based on the RRG algorithm, K-means clustering, and Dynamic Time Warping (DTW) similarity metric to address the problem. The mixed algorithm succeeds in generating a set of paths with diversity in an obstacle constrained airspace between Paris-Toulouse and London-Toulouse airports. This tool could help to reduce the workload of pilots and ATCs when such a situation arises.","alternative trajectory; clustering; metrics; RRG; similarity","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-20","","","Control & Simulation","","",""
"uuid:e5c9aeb0-9c9b-4185-a806-d9d83d59b974","http://resolver.tudelft.nl/uuid:e5c9aeb0-9c9b-4185-a806-d9d83d59b974","Towards Greener ICUs: Redesigning the Use of Disposable Gloves","van den Berg, Lisanne (Student TU Delft); Albayrak, A. (TU Delft Applied Ergonomics and Design); Hunfeld, Nicole (Erasmus MC); Diehl, J.C. (TU Delft Design for Sustainability)","Melles, M. (editor); Goossens, R.H. (editor)","2024","This research and design project is part of the Green ICU initiative and focused on reducing the environmental impact of gloves at the Intensive Care Unit (ICU) of the Erasmus Medical Center (EMC). At the ICU of the EMC around 108 gloves are used per patient per day; to protect the user (healthcare staff) from infections. The high frequency of use and the resource-intensive production define disposable nitrile gloves as one of the ‘hotspots’ contributing to the environmental impact created by the ICU. This research and design project addressed the problem from three different perspectives: user-centred, product-centred and supply-centred. The extensive research resulted in three design directions on how to reduce the environmental impact of gloves. Subsequently, all insights from the research were brought together into five design building blocks. These design building blocks provided guidance for the design phase of the project. The project resulted in a redesign of the current glove dispensers. The final design is named ‘GloVe’, a vertical dispense system. By incorporating the five building blocks, the design can provide benefits for multiple stakeholders within the healthcare system. It reduces the environmental impact of gloves in the ICU by dispensing one glove at a time. Furthermore, the gloves are dispensed at the cuff, which comes in little contact with the patient. The vertical movement is pleasant to the user. The use of colour for different sizes makes it clear to the care assistant which box should go in which holder. Also, nurses will see at a glance, which size gloves they are dispensing. The small V-shaped opening makes the undesirable behaviour, of placing gloves back, almost impossible.","Design for sustainability; Gloves; User-centred; Medisign; Infection prevention; Intensive care unit","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-05","","","Applied Ergonomics and Design","","",""
"uuid:684cc631-ebbd-4f05-94be-a7c64cacd240","http://resolver.tudelft.nl/uuid:684cc631-ebbd-4f05-94be-a7c64cacd240","Network Robustness Improvement Based on Alternative Paths Consideration","Lebègue, J. (TU Delft Control & Simulation; Sopra Steria); Delahaye, Daniel (Ecole Nationale de L’Aviation Civile); Hoekstra, J.M. (TU Delft Control & Simulation)","Martins, Ana Lucia (editor); Ferreira, Joao C. (editor); Kocian, Alexander (editor); Tokkozhina, Ulpan (editor); Helgheim, Berit Irene (editor); Bråthen, Svein (editor)","2024","Many transportation networks have complex infrastructures (road, rail, airspace, etc.). The quality of service in air transportation depends on weather conditions. Technical failures of the aircraft, bad weather conditions, strike of the company’s staff cause delays and disrupt traffic. How can the robustness of such networks be improved? Improving the robustness of air transportation would reduce the cascading delays between airports and improve the passenger journey. Many studies have been done to find critical links and nodes, but not so many analyze the paths. In this paper, we propose a new method to measure network robustness based on alternative paths. Besides improving the robustness of the French (respectively Turkish Airlines and European) low-cost flight network by 19% (respectively 16% and 6.6%), the method attempts to show the relevance of analyzing the network vulnerability from a path-based approach.","Floyd-Warshall algorithm; Passenger-centric model; Robust network; Simulated annealing; Topology; Transport","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-20","","","Control & Simulation","","",""
"uuid:adfeb14a-2407-438a-9ade-ca027934e2d0","http://resolver.tudelft.nl/uuid:adfeb14a-2407-438a-9ade-ca027934e2d0","Fleet scheduling for electric towing of aircraft under limited airport energy capacity","Zoutendijk, M. (TU Delft Control & Simulation); Mitici, M.A. (TU Delft Air Transport & Operations; Universiteit Utrecht)","","2024","Taxiing aircraft using electric vehicles is seen as an effective solution to meet aviation targets of climate neutrality. However, making the transition to electric taxiing operations is expected to significantly increase the electricity demand at airports. In this paper we propose a mixed-integer linear program to schedule electric vehicles for aircraft towing and battery charging, while considering a limit for the supply of energy. The objective of the schedule is to maximize emissions savings. For computational tractability, we develop an Adaptive Large Neighbourhood Search which makes use of multiple local search heuristics to identify scheduling solutions. For daily scheduling with a small fleet size, the developed heuristic achieves solutions with an average 4% gap to the best linear programming solution. The results show that charging the vehicles during daytime is essential to maximize saved emissions: removing charging opportunities for a few hours during the day reduces the performance by an average of 6.4%. In addition, it is found that fast charging leads to low vehicle downtime, unless the battery size exceeds 750kWh, when charging rates over 150kW become unnecessary. Overall, our model provides support for infrastructure planning of airports during the transition to aircraft electric taxiing.","Adaptive Large Neighbourhood Search; Charging strategy; Electric taxiing; Electricity capacity; Fleet scheduling","en","journal article","","","","","","","","","","","Control & Simulation","","",""
"uuid:8884bec9-7326-436a-8723-86870fb14c87","http://resolver.tudelft.nl/uuid:8884bec9-7326-436a-8723-86870fb14c87","Single-molecule visualization of twin-supercoiled domains generated during transcription","Janissen, R. (TU Delft BN/Bionanoscience); Barth, R. (TU Delft BN/Cees Dekker Lab); Polinder, M.L. (TU Delft BN/Cees Dekker Lab); van der Torre, J. (TU Delft BN/Cees Dekker Lab); Dekker, C. (TU Delft BN/Cees Dekker Lab)","","2024","Transcription-coupled supercoiling of DNA is a key factor in chromosome compaction and the regulation of genetic processes in all domains of life. It has become common knowledge that, during transcription, the DNA-dependent RNA polymerase (RNAP) induces positive supercoiling ahead of it (downstream) and negative supercoils in its wake (upstream), as rotation of RNAP around the DNA axis upon tracking its helical groove gets constrained due to drag on its RNA transcript. Here, we experimentally validate this so-called twin-supercoiled-domain model with in vitro real-time visualization at the single-molecule scale. Upon binding to the promoter site on a supercoiled DNA molecule, RNAP merges all DNA supercoils into one large pinned plectoneme with RNAP residing at its apex. Transcription by RNAP in real time demonstrates that up- and downstream supercoils are generated simultaneously and in equal portions, in agreement with the twin-supercoiled-domain model. Experiments carried out in the presence of RNases A and H, revealed that an additional viscous drag of the RNA transcript is not necessary for the RNAP to induce supercoils. The latter results contrast the current consensus and simulations on the origin of the twin-supercoiled domains, pointing at an additional mechanistic cause underlying supercoil generation by RNAP in transcription.","","en","journal article","","","","","","","","","","BN/Bionanoscience","BN/Cees Dekker Lab","","",""
"uuid:371423e2-8928-4460-b5f1-37427fc08c00","http://resolver.tudelft.nl/uuid:371423e2-8928-4460-b5f1-37427fc08c00","Design and In Vitro Validation of an Orthopaedic Drill Guide for Femoral Stem Revision in Total Hip Arthroplasty","Klok, J.W.A. (TU Delft Medical Instruments & Bio-Inspired Technology); Groenewegen, Jessica (SIMtoCARE); Temmerman, Olivier (Noordwest Hospital); Van Straten, Niels (Van Straten Medical); van Straten, Bart (Van Straten Medical); Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology); Horeman, T. (TU Delft Medical Instruments & Bio-Inspired Technology)","","2024","Objective: Cemented total hip arthroplasty (THA) demonstrates superior survival rates compared to uncemented procedures. Nevertheless, most younger patients opt for uncemented THA, as removing well-fixed bone cement in the femur during revisions is complex, particularly the distal cement plug. This removal procedure often increases the risk of femoral fracture or perforation, haemorrhage and weakening bone due to poor drill control and positioning. Aim of this study was to design a novel drill guide to improve drill positioning. Methods and procedures: A novel orthopaedic drill guide was developed, featuring a compliant centralizer activated by a drill guide actuator. Bone models were prepared to assess centralizing performance. Three conditions were tested: drilling without guidance, guided drilling with centralizer activation held, and guided drilling with centralizer activation released. Deviations from the bone centre were measured at the entry and exit point of the drill. Results: In the centralizing performance test, the drill guide significantly reduced drill hole deviations in both entry and exit points compared to the control (p < 0.05). The absolute deviation on the exit side of the cement plug was 10.59mm (SD 1.56) for the 'No drill guide' condition, 3.02mm (SD 2.09) for 'Drill guide - hold' and 2.12mm (SD 1.71) for 'Drill guide - release'. The compliant drill guide centralizer significantly lowered the risk of cortical bone perforation during intramedullary canal drilling in the bone models due to better control of the cement drill position. Clinical and Translational Impact Statement: The drill guide potentially reduces perioperative risks in cemented femoral stem revision. Future research should identify optimal scenarios for its application.","Drill positioning; guiding mechanisms; medical device prototyping; novel design; sustainable design; total hip arthroplasty","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:2606b384-813c-4ae5-9637-c69b3064834c","http://resolver.tudelft.nl/uuid:2606b384-813c-4ae5-9637-c69b3064834c","The Moon as an effective propellant source: A comprehensive exergy analysis from extraction to depot","Gallbrecht, M. M. (European Space Agency (ESA); Student TU Delft); Cervone, A. (TU Delft Astrodynamics & Space Missions); Vincent-Bonnieu, S. (European Space Agency (ESA))","","2024","Establishing a permanent lunar base has gained increasing attention since it offers opportunities for international cooperation and the commercialization of space, forming the foundation and testing ground for a human existence independent from Earth. Essential to future missions beyond cislunar space is the exploration and in situ processing of the Moon's resources, especially the sustainable production of energetic resources and propellants. Utilizing in situ generated propellants can dramatically reduce transportation costs by removing the need to source propellants from Earth. Resources on the Moon are limited, and the extraction of available resources are energy-intensive processes demanding advanced techniques and technologies. Consequently, one of the biggest challenges lies in developing process architectures with a positive energy balance, for which comprehensive analyses are still missing. The focus currently lies on the extraction of water ice from lunar regolith and the production of hydrogen and oxygen through water electrolysis. However, alternative fuel and process options may reduce the energy cost while providing equivalent energetic revenue. In the scope of this research, the infrastructure and technologies required for extraction, refining, and storing are assumed to exist in cislunar space; therefore, only the operating cost is considered. Exergy analyses of in situ extraction methods are conducted to investigate whether the required energetic budget allows sustainable implementation. The analysis includes extraction methods and propellant options to reveal the extent to which alternatives to hydrogen are feasible. Exergy analyses determine thermodynamic losses of energy flows giving the ground for process optimization. The exergy destructed represents the margin of improvement within the process architecture and thus reflects the process's thermodynamic and economic value while allowing a more distinct examination of energy use. Assuming the availability of water and carbon dioxide ice in permanently shadowed regions, the analysis shows that choosing methane instead of hydrogen in combination with oxygen as propellants can reduce the required exergy input by up to a third. An example mission allows to directly compare the operating cost of the extraction processes for the different propellant options. The mission entails a spacecraft propelled by a liquid bipropellant engine utilizing the extracted propellant and transporting a payload of the same propellant to a depot located in lunar near-rectilinear halo orbit (NRHO). Although abundant in space, the results suggest that hydrogen may not be the only or even energetically cost-effective resource for developing cislunar and Martian space infrastructures. Likewise, sustainable extraction of propellants suitable for current and future propulsion systems will foster humanity's reach further into the solar system.","Depot; Economical; Exergy; Moon; Propellent","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-02","","","Astrodynamics & Space Missions","","",""
"uuid:f601a4e0-25c4-43dc-ab09-2753787e4ed9","http://resolver.tudelft.nl/uuid:f601a4e0-25c4-43dc-ab09-2753787e4ed9","Distribution of economic damages due to climate-driven sea-level rise across European regions and sectors","Cortés Arbués, I. (TU Delft Multi Actor Systems; TU Delft Policy Analysis); Chatzivasileiadis, T. (TU Delft Multi Actor Systems; TU Delft Policy Analysis); Ivanova, Olga (Planbureau voor de Leefomgeving); Storm, S.T.H. (TU Delft Values Technology and Innovation; TU Delft Economics of Technology and Innovation); Bosello, Francesco (Ca' Foscari University Venice; RFF-CMCC European Institute on Economics and the Environment (EIEE)); Filatova, T. (TU Delft Multi Actor Systems; TU Delft Policy Analysis)","","2024","Economic costs of climate change are conventionally assessed at the aggregated global and national levels, while adaptation is local. When present, regionalised assessments are confined to direct damages, hindered by both data and models’ limitations. This article goes beyond the aggregated analysis to explore direct and indirect economic consequences of sea level rise (SLR) at regional and sectoral levels in Europe. Using a dynamic computable general equilibrium model and novel datasets, we estimate the distribution of losses and gains across regions and sectors. A comparison of a high-end scenario against a no-climate-impact baseline suggests a GDP loss of 1.26% (€871.8 billion) for the whole EU&UK. Conversely our refined assessments show that some coastal regions lose 9.56–20.84% of GDP, revealing striking regional disparities. Inland regions grow due to the displaced demand from coastal areas, but the GDP gains are small (0–1.13%). While recovery benefits the construction sector, public services and industry face significant downturns. We show that prioritising recovery of critical sectors locally reduces massive regional GDP losses, at negligible costs to the overall European economy. Our analysis traces regional economic restructuring triggered by SLR, underscoring the necessity of region-specific adaptation policies that embrace uneven geographic impacts and unique sectoral profiles to inform resilient strategy design.","","en","journal article","","","","","","","","","","Multi Actor Systems","Policy Analysis","","",""
"uuid:c390ab8c-1ff0-44d8-8885-a6b1e7088503","http://resolver.tudelft.nl/uuid:c390ab8c-1ff0-44d8-8885-a6b1e7088503","Characterization and mechanical removal of metallic aluminum (Al) embedded in weathered municipal solid waste incineration (MSWI) bottom ash for application as supplementary cementitious material","Chen, B. (TU Delft Materials and Environment); Chen, J. (TU Delft Materials and Environment); França de Mendonça Filho, F. (TU Delft Materials and Environment); Sun, Yubo (Universiteit Gent); van Zijl, Marc Brito (Mineralz); Copuroglu, Oguzhan (TU Delft Materials and Environment); Ye, G. (TU Delft Materials and Environment; Universiteit Gent)","","2024","Municipal solid waste incineration (MSWI) bottom ash, due to its high mineral content, presents great potential as supplementary cementitious material (SCM). Weathering, also known as aging, is a treatment process commonly employed in waste management to minimize the risk of heavy metal leaching from MSWI bottom ash. Using weathered MSWI bottom ash to produce blended cement pastes is considered as a high-value-added and sustainable waste disposal solution. However, a critical challenge arises from the metallic aluminum (Al) in weathered MSWI bottom ash, which is known to induce detrimental effects such as volume expansion and strength loss of blended cement pastes. While most metallic Al in weathered MSWI bottom ash can be removed with eddy current separators in metal recovery plants, the residual metallic Al, owing to its small particle size, cannot be removed with the same technique. This study is dedicated to addressing this issue. An in-depth analysis was conducted on residual metallic Al embedded in weathered MSWI bottom ash particles, aiming to guide the removal of this metal. This analysis revealed that mechanical removal was the most suitable method for extracting metallic Al. The specific processes and mechanisms underlying this method were elucidated. After reducing metallic Al content in weathered MSWI bottom ash by 77 %, a significant improvement in the quality of blended cement pastes was observed. This work contributes to the broader adoption of mechanical treatments for removing residual metallic Al from weathered MSWI bottom ash and facilitates the application of treated ash as SCM.","Mechanical treatments; Metallic aluminum (Al) distribution; Municipal solid waste incineration (MSWI) bottom ash; Supplementary cementitious material (SCM); Weathering","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:a2b62e51-13d8-4f72-962d-3150dd00670c","http://resolver.tudelft.nl/uuid:a2b62e51-13d8-4f72-962d-3150dd00670c","Traditional adhesive production systems in Zambia and their archaeological implications","Fajardo, Sebastian (TU Delft Team Joris Dik; Universiteit Leiden); Zeekaf, Jelte (Wageningen University & Research); van Andel, Tinde (Wageningen University & Research; Naturalis Biodiversity Center; Universiteit Leiden); Maombe, Christabel (National Heritage Conservation Commission); Nyambe, Terry (Livingstone Museum); Mudenda, George (Livingstone Museum); Aleo, A. (TU Delft Team Joris Dik); Kayuni, Martha Nchimunya (Max Planck Institute of Geoanthropology); Langejans, G.H.J. (TU Delft Team Joris Dik; University of Johannesburg)","","2024","This study explores traditional adhesives using an ethnobiological approach within a multisocioecological context in Zambia. Through semi-structured interviews, videotaped demonstrations, and herbarium collections, we investigated the traditional adhesives people know and use, the flexibility of production processes, resource usage, and knowledge transmission in adhesive production. Our findings reveal flexibility in adhesive production systems. People use a wide range of organic and inorganic materials in their adhesive recipes. Recipes are flexible, demonstrating the ability to adapt to changes and substitute materials as needed to achieve the desired end product. Additionally, our study reveals a variety of redundant pathways for knowledge transmission typically confined within individual population groups. These include same-sex vertical transmission and distinct learning spaces and processes. Also, we identified material procurement zones showing that people are prepared to travel 70 km for ingredients. We use our findings to review the archaeology and we discuss the identification of archaeological adhesives, the functional roles of adhesive materials, adhesive storage, and the sustained human interaction with species from families such as Euphorbiaceae and Apiade. Our findings underscore the diversity and adaptability of traditional adhesive production and suggest that further research on adhesives would reveal similar diversity within the archaeological record.","Adaptive systems; Adhesives; Complex technology; Ethnobiology; Euphorbiaceae; Glue; Knowledge transmission; Resilience; Resin; Zambia","en","journal article","","","","","","","","","","","Team Joris Dik","","",""
"uuid:3a823325-8b9b-4bae-bf10-becc58901b21","http://resolver.tudelft.nl/uuid:3a823325-8b9b-4bae-bf10-becc58901b21","The geography of collective bargaining in French multi-establishment companies","Askenazy, Philippe (Maurice Halbwachs Center (CMH)); Cottineau, C. (TU Delft Urban Studies; Maurice Halbwachs Center (CMH))","","2024","Despite growing interest in the firm bargaining process, little research focuses on the structure of bargaining within multi-establishment firms. We question whether running negotiations at the workplace level and/or firm level is a strategic choice for employers. We hypothesize that the level chosen depends on the geography of the firm. Employers face a trade-off: workplace bargaining is more efficient because it meets local conditions; yet higher level negotiations increase coordination costs for workers and weakens their bargaining power, which can benefit the employer. Using a French representative survey, we find a significant relation between the level of bargaining within a firm and the number, spatial distribution and heterogeneity of its establishments, suggesting that the structure of multi-establishment firms can inform the level at which collective bargaining takes place.","","en","journal article","","","","","","","","","","","Urban Studies","","",""
"uuid:37a7080d-b540-4cfd-bc75-9a1315aa8c60","http://resolver.tudelft.nl/uuid:37a7080d-b540-4cfd-bc75-9a1315aa8c60","Predicting nodal influence via local iterative metrics","Zhang, S. (TU Delft Multimedia Computing); Hanjalic, A. (TU Delft Intelligent Systems); Wang, H. (TU Delft Multimedia Computing)","","2024","Nodal spreading influence is the capability of a node to activate the rest of the network when it is the seed of spreading. Combining nodal properties (centrality metrics) derived from local and global topological information respectively has been shown to better predict nodal influence than using a single metric. In this work, we investigate to what extent local and global topological information around a node contributes to the prediction of nodal influence and whether relatively local information is sufficient for the prediction. We show that by leveraging the iterative process used to derive a classical nodal centrality such as eigenvector centrality, we can define an iterative metric set that progressively incorporates more global information around the node. We propose to predict nodal influence using an iterative metric set that consists of an iterative metric from order 1 to K produced in an iterative process, encoding gradually more global information as K increases. Three iterative metrics are considered, which converge to three classical node centrality metrics, respectively. In various real-world networks and synthetic networks with community structures, we find that the prediction quality of each iterative based model converges to its optimal when the metric of relatively low orders (K∼4) are included and increases only marginally when further increasing K. This fast convergence of prediction quality with K is further explained by analyzing the correlation between the iterative metric and nodal influence, the convergence rate of each iterative process and network properties. The prediction quality of the best performing iterative metric set with K=4 is comparable with the benchmark method that combines seven centrality metrics: their prediction quality ratio is within the range [91%,106%] across all three quality measures and networks. In two spatially embedded networks with an extremely large diameter, however, iterative metric of higher orders, thus a large K, is needed to achieve comparable prediction quality with the benchmark.","OA-Fund TU Delft","en","journal article","","","","","","","","","","Intelligent Systems","Multimedia Computing","","",""
"uuid:0a28a9de-726c-4376-8a15-70cfd8f50bc1","http://resolver.tudelft.nl/uuid:0a28a9de-726c-4376-8a15-70cfd8f50bc1","A hierarchic isogeometric hyperelastic solid-shell","Leonetti, Leonardo (University of Calabria; Ho Chi Minh City University of Technology (HCMUT)); Verhelst, H.M. (TU Delft Ship and Offshore Structures; TU Delft Numerical Analysis)","","2024","The present study aims to develop an original solid-like shell element for large deformation analysis of hyperelastic shell structures in the context of isogeometric analysis (IGA). The presented model includes a new variable to describe the thickness change of the shell and allows for the application of unmodified three-dimensional constitutive laws defined in curvilinear coordinate systems and the analysis of variable thickness shells. In this way, the thickness locking affecting standard solid-shell-like models is cured by enhancing the thickness strain by exploiting a hierarchical approach, allowing linear transversal strains. Furthermore, a patch-wise reduced integration scheme is adopted for computational efficiency reasons and to annihilate shear and membrane locking. In addition, the Mixed-Integration Point (MIP) format is extended to hyperelastic materials to improve the convergence behaviour, hence the efficiency, in Newton iterations. Using benchmark problems, it is shown that the proposed model is reliable and resolves locking issues that were present in the previously published isogeometric solid-shell formulations.","Hyperelastic materials; Isogeometric analysis; Large deformations; Large Strains; MIP Newton; Solid-shells","en","journal article","","","","","","","","","","","Ship and Offshore Structures","","",""
"uuid:a16ebbae-f8d3-4453-a38a-f5de9e99b92d","http://resolver.tudelft.nl/uuid:a16ebbae-f8d3-4453-a38a-f5de9e99b92d","Estimation of the incubation time distribution in the singly and doubly interval censored model","Groeneboom, P. (TU Delft Statistics)","","2024","We analyze nonparametric estimators for the distribution function of the incubation time in the singly and doubly interval censoring model. The classical approach is to use parametric families like Weibull, log-normal or gamma distributions in the estimation procedure. We propose nonparametric estimates for functions of the observations, which stay closer to the data than the classical parametric methods. We also give explicit limit distributions for discrete versions of the models and apply this to compute confidence intervals. The methods complement the analysis of the continuous model in Groeneboom (2021, 2023). R scripts for computation of the estimates are provided in Groeneboom (2020).","confidence intervals; deconvolution; double interval censoring; Fisher information; incubation time; single interval censoring; support reduction","en","journal article","","","","","","","","","","","Statistics","","",""
"uuid:8e37b9b1-c3ab-4c93-b6d3-1c93ed4742b5","http://resolver.tudelft.nl/uuid:8e37b9b1-c3ab-4c93-b6d3-1c93ed4742b5","Understanding people-centered planning practice in Europe: An institutionalist comparison between urban development projects in Vienna and Helsingborg","Janssen, C. (TU Delft Practice Chair Urban Area Development)","","2024","Pursuing people-centered planning practices (PCPs) such as participatory approaches demands a better understanding of how their operationalization relates to contextual structures and conditions in urban governance. By comparing two cases of social sustainability operationalization in Austrian and Swedish urban development projects based on Ostrom’s IAD-framework, this article identifies institutions relating to performed people-centered activities. The findings reveal that PCPs do not necessarily benefit from highly formalized rules prescribing specific localized activities. Instead, they are shaped by institutions that (1) position the actors responsible for performing people-centered activities, (2) define strong socially-oriented and innovation-oriented outcomes, and (3) enable funding that upholds long-term public interests within the markets that co-shape the projects.","IAD framework; urban development project; localism; people-centered; social sustainability; participatory planning","en","journal article","","","","","","","","","","","Practice Chair Urban Area Development","","",""
"uuid:a7fdaa8a-4d72-4c9a-87f6-4da6c2726b73","http://resolver.tudelft.nl/uuid:a7fdaa8a-4d72-4c9a-87f6-4da6c2726b73","Promoting the private rented sector in metropolitan China: Key challenges and solutions","Li, B. (TU Delft Real Estate Management); van der Heijden, H.M.H. (TU Delft Real Estate Management); Jansen, S.J.T. (TU Delft Real Estate Management); Yan, Juan (Tongji University); Boelhouwer, P.J. (TU Delft Real Estate Management)","","2024","The private rented sector (PRS) plays an increasingly important role in accommodating young people and migrants in China’s metropolitan cities. However, the PRS in China is still underdeveloped, as evidenced by, e.g. a low degree of professionalisation, lack of basic rental laws and regulations, and poor housing experiences of tenants. The purpose of the current article is to identify the main challenges towards a well-functioning PRS, as perceived by Chinese local governments, landlords, and tenants, and to propose possible solutions to cope with these challenges. After reviewing both academic and grey literature and exploring the results of our previous research, we found that these challenges result from three main root causes, i.e. power imbalance between landlords and tenants, inadequate institutional arrangements, and path dependence on the past productivism model. Based on the analysis, a number of recommendations were proposed, including formalising the PRS, introducing regulations, setting minimum housing standards, and increasing public school availability to enhance equal citizenship rights between renters and homeowners.","private rented sector; challenges; solutions; rent regulation; housing inequality","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-04","","","Real Estate Management","","",""
"uuid:4e28b84a-ae73-4dc9-b292-a8c0f17673bb","http://resolver.tudelft.nl/uuid:4e28b84a-ae73-4dc9-b292-a8c0f17673bb","Multi-objective calibration of vertical-axis wind turbine controllers: balancing aero-servo-elastic performance and noise","Brandetti, L. (TU Delft Wind Energy); Mulders, S.P. (TU Delft Team Mulders); Merino Martinez, R. (TU Delft Aircraft Noise and Climate Effects); Watson, S.J. (TU Delft Wind Energy); van Wingerden, J.W. (TU Delft Team Jan-Willem van Wingerden)","","2024","Vertical-axis wind turbines (VAWTs) are considered promising solutions for urban wind energy generation due to their design, low maintenance costs, and reduced noise and visual impact compared to horizontal-axis wind turbines (HAWTs). However, deploying these turbines close to densely populated urban areas often triggers considerable local opposition to wind energy projects. Among the primary concerns raised by communities is the issue of noise emissions. Noise annoyance should be considered in the design and decision-making process to foster the social acceptance of VAWTs in urban environments. At the same time, maximising the operational efficiency of VAWTs in terms of power generation and actuation effort is equally important. This paper balances noise and aero-servo-elastic performance by formulating and solving a multi-objective optimisation problem from a controller calibration perspective. Psychoacoustic annoyance is taken as a novel indicator for the noise objective by providing a more reliable estimate of the human perception of wind turbine noise than conventional sound metrics. The computation of the psychoacoustic annoyance metric is made feasible by integrating it with an accurate and computationally efficient low-fidelity noise prediction model. For optimisation, an advanced partial-load control scheme – often used in industrial turbines – is considered, with the Kω2 controller as a baseline for comparison. Optimal solutions balancing the defined objectives are identified using a multi-criteria decision-making method (MCDM) and are subsequently assessed using a frequency-domain controller analysis framework and mid-fidelity time-domain aero-servo-elastic simulations. The MCDM results indicate the potential application of this controller in small-scale urban VAWTs to attain power gains of up to 39 % on one side and to trade off a reduction in actuation effort of up to 25 % at the cost of only a 2 % power decrease and a 6 % increase in psychoacoustic annoyance on the other side compared to the baseline. These findings confirm the flexible structure of the optimally calibrated wind speed estimator and tip-speed ratio (WSE–TSR) tracking controller, effectively balancing aero-servo-elastic performance with noise emissions and marking the first instance of integrating residential concerns into the decision-making process.","","en","review","","","","","","","","","","","Wind Energy","","",""
"uuid:f4487e7b-95e3-4d32-b10f-865a2195aa24","http://resolver.tudelft.nl/uuid:f4487e7b-95e3-4d32-b10f-865a2195aa24","A novel machine learning model to design historical-independent health indicators for composite structures","Moradi, M. (TU Delft Group Zarouchas); Gul, F.C. (TU Delft Group Zarouchas); Zarouchas, D. (TU Delft Group Zarouchas)","","2024","Developing comprehensive health indicators (HIs) for composite structures encompassing various damage types is challenging due to the stochastic nature of damage accumulation and uncertain events (like impact) during operation. This complexity is amplified when striving for HIs independent of historical data. This paper introduces an AI-driven approach, the Hilbert transform-convolutional neural network under a semi-supervised learning paradigm, to designing reliable HIs (fulfilling requirements, referred to as 'fitness'). It exclusively utilizes current guided wave data, eliminating the need for historical information. Ensemble learning techniques were also used to enhance HI quality while reducing deep learning randomness. The fitness equation is refined for dependable comparisons and practicality. The methodology is validated through investigations on T-single stiffener CFRP panels under compression-fatigue and dogbone CFRP specimens under tension-fatigue loadings, showing high performance of up to 93% and 81%, respectively, in prognostic criteria.","Compression-compression fatigue; Intelligent health indicator; Prognostics and health management; Semi-supervised learning; T-single stiffener CFRP; Tension-tension fatigue","en","journal article","","","","","","","","","","","Group Zarouchas","","",""
"uuid:9a1569e1-d573-43e2-93a4-257dfd6cd22f","http://resolver.tudelft.nl/uuid:9a1569e1-d573-43e2-93a4-257dfd6cd22f","Global diversity of enterococci and description of 18 previously unknown species","Schwartzman, Julia A. (Harvard Medical School; University of Southern California); Lebreton, Francois (Harvard Medical School; Walter Reed Army Institute of Research); Salamzade, Rauf (Massachusetts Institute of Technology; University of Wisconsin School of Medicine and Public Health); Shea, Terrance (Massachusetts Institute of Technology); Martin, Melissa J. (Harvard Medical School; Walter Reed Army Institute of Research); Schaufler, Katharina (Harvard Medical School; Greifswald University; Christian-Albrechts-Universität zu Kiel); Urhan, A. (TU Delft Pattern Recognition and Bioinformatics; Massachusetts Institute of Technology); Abeel, T.E.P.M.F. (TU Delft Pattern Recognition and Bioinformatics; Massachusetts Institute of Technology); Camargo, Ilana L.B.C. (Universidade de São Paulo)","","2024","Enterococci are gut microbes of most land animals. Likely appearing first in the guts of arthropods as they moved onto land, they diversified over hundreds of millions of years adapting to evolving hosts and host diets. Over 60 enterococcal species are now known. Two species, Enterococcus faecalis and Enterococcus faecium, are common constituents of the human microbiome. They are also now leading causes of multidrug-resistant hospital-associated infection. The basis for host association of enterococcal species is unknown. To begin identifying traits that drive host association, we collected 886 enterococcal strains from widely diverse hosts, ecologies, and geographies. This identified 18 previously undescribed species expanding genus diversity by >25%. These species harbor diverse genes including toxins and systems for detoxification and resource acquisition. Enterococcus faecalis and E. faecium were isolated from diverse hosts highlighting their generalist properties. Most other species showed a more restricted distribution indicative of specialized host association. The expanded species diversity permitted the Enterococcus genus phylogeny to be viewed with unprecedented resolution, allowing features to be identified that distinguish its four deeply rooted clades, and the entry of genes associated with range expansion such as B-vitamin biosynthesis and flagellar motility to be mapped to the phylogeny. This work provides an unprecedentedly broad and deep view of the genus Enterococcus, including insights into its evolution, potential new threats to human health, and where substantial additional enterococcal diversity is likely to be found.","antibiotic resistance; Enterococcus; genomics; global diversity; host microbe interaction","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:71534aae-41f4-435a-8402-dd23e104483a","http://resolver.tudelft.nl/uuid:71534aae-41f4-435a-8402-dd23e104483a","Damage Classification of a Bolted Connection using Guided Waves and Explainable Artificial Intelligence","Hu, M. (TU Delft Structural Integrity & Composites; Harbin Engineering University); Yue, N. (TU Delft Group Yue); Groves, R.M. (TU Delft Group Groves)","","2024","With the improvements in computational power and advances in chip and sensor technology, the applications of machine learning (ML) technologies in structural health monitoring (SHM) are increasing rapidly. Compared with traditional methods, deep learning based SHM (Deep SHM) methods are more efficient and have a higher accuracy. However, due to the black box nature of deep learning, the trained models are usually difficult to interpret, which blocks their practical application. Therefore, it is of great importance to develop explainable artificial intelligence (XAI) methods to understand the internal decision-making mechanisms of damage classification in Deep SHM. In this paper, a novel XAI algorithm named Deep Gradient-weighted Class Activation Mapping (Deep Grad CAM) is proposed by combining the existing method Grad CAM with the convolutional neural network (CNN) deconvolution mechanism. In this paper, Deep Grad CAM is used to interpret a one-dimensional convolutional neural network trained to detect bolt loosening based on guided wave propagation. The interpretation performance of Deep Grad CAM is compared with Grad CAM, and their performances are quantified using Infidelity. The results show that the Infidelity of Deep Grad CAM is much smaller than that of Grad CAM, indicating significant improvements in explanation accuracy and reliability.","deep learning; explainable AI (XAI); guided waves; one-dimensional convolutional neural network (1D CNN); structural health monitoring (SHM)","en","journal article","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:62166ffb-ad44-4afc-aedd-234b9cd4a399","http://resolver.tudelft.nl/uuid:62166ffb-ad44-4afc-aedd-234b9cd4a399","Carbon solute drag effect on the growth of carbon supersaturated bainitic ferrite: Modeling and experimental validations","Dai, Zongbiao (Xi’an Jiaotong University); Chen, H. (TU Delft Novel Aerospace Materials; Tsinghua University); Sun, Junjie (Xi’an Jiaotong University); van der Zwaag, S. (TU Delft Group Garcia Espallargas); Sun, Jun (Xi’an Jiaotong University)","","2024","The carbon partitioning and lengthening rate of bainitic ferrite (αb) are excellent experimental parameters to estimate our level of understanding of the mechanism of bainitic transformation from a continuum perspective and our ability to capture it in analytical expressions. For Fe-C alloys and relatively simple steels the classical Zener-Hillert theory captures the bainitic transformation rather well but mispredicts the level of carbon in solution in the bainite and overestimates the lengthening rates for transformations at lower temperatures. To address this issue, this paper presents a new thermo-kinetic model based on the Zener-Hillert theory and the Gibbs energy balance concept to simulate the lengthening behavior of αb in the Fe-C and low alloyed steels. The model incorporates the effect of the temperature dependent carbon diffusion within the migrating interface via a temperature dependent ferrite/austenite interfacial energy and a temperature dependent diffusion coefficient but does not impose local equilibrium across the interface. The good agreement between the model predictions and nine sets of published experiments indicates that both the carbon supersaturation in αb and the slower lengthening rate are caused by carbon diffusion within the migrating interface. It is found that the degree of carbon supersaturation in αb increases significantly with decreasing temperature. Consequently, the enhanced carbon solute drag effect, resulting from carbon diffusion within the interface, strongly retards the lengthening rates of αb at lower temperatures. Transformation strain is shown to have a modest effect on the lengthening rates but to lower the degree of carbon supersaturation.","Bainite formation; Carbon diffusion; Carbon supersaturation; Energy dissipation; Lengthening kinetics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-02","","","Novel Aerospace Materials","","",""
"uuid:1c5b4a48-1f6c-46fe-a480-82354e07aa5c","http://resolver.tudelft.nl/uuid:1c5b4a48-1f6c-46fe-a480-82354e07aa5c","Neural network relief: a pruning algorithm based on neural activity","Dekhovich, A. (TU Delft Team Marcel Sluiter); Tax, D.M.J. (TU Delft Pattern Recognition and Bioinformatics); Sluiter, M.H.F. (TU Delft Team Marcel Sluiter); Bessa, M.A. (Brown University)","","2024","Current deep neural networks (DNNs) are overparameterized and use most of their neuronal connections during inference for each task. The human brain, however, developed specialized regions for different tasks and performs inference with a small fraction of its neuronal connections. We propose an iterative pruning strategy introducing a simple importance-score metric that deactivates unimportant connections, tackling overparameterization in DNNs and modulating the firing patterns. The aim is to find the smallest number of connections that is still capable of solving a given task with comparable accuracy, i.e. a simpler subnetwork. We achieve comparable performance for LeNet architectures on MNIST, and significantly higher parameter compression than state-of-the-art algorithms for VGG and ResNet architectures on CIFAR-10/100 and Tiny-ImageNet. Our approach also performs well for the two different optimizers considered—Adam and SGD. The algorithm is not designed to minimize FLOPs when considering current hardware and software implementations, although it performs reasonably when compared to the state of the art.","Connection pruning; Iterative pruning; Neural network pruning; Sparsity","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-05","","","Team Marcel Sluiter","","",""
"uuid:ad8e8a0b-7228-4f33-9a86-5b51f774922b","http://resolver.tudelft.nl/uuid:ad8e8a0b-7228-4f33-9a86-5b51f774922b","Downsizing and the use of timber as embodied carbon reduction strategies for new-build housing: A partial life cycle assessment","Souaid, C. (TU Delft Urban Development Management); ten Caat, P.N. (TU Delft Environmental & Climate Design); Meijer, A. (TU Delft Environmental & Climate Design); Visscher, H.J. (TU Delft Design & Construction Management)","","2024","The 2050 decarbonization goals coupled with the growing housing shortage in Europe intensify the pressure on new-build dwellings to enhance their energy performance. Beyond a zero operational energy, the focus has shifted towards reducing embodied carbon (EC). Against this backdrop, this study investigates the simultaneous impact of downsizing and the use of timber in new-build dwellings, EC reduction strategies seldom explored concurrently. Through partial life cycle assessments, three scenarios are modelled: the Small, Medium, and Large House, with two construction variations for each, comparing a modular timber design to a conventional concrete alternative. Designs are based on dwellings built in Almere, the Netherlands. Data is extracted from the Swiss Ecoinvent database using the TOTEM tool and the static −1/+1 approach for biogenic carbon accounting is adopted. Results show a total EC ranging from 42,608 to 70,384 kgCO2eq for the timber designs versus 54,681 to 91,270 kgCO2eq for their concrete counterparts. Findings suggest that the relationship between house size and EC is sublinear whereby a house twice the size entails less than twice the EC emissions. Only the simultaneous implementation of downsizing and the use of timber achieved 53% carbon savings. The discussion explores implications of outcomes across academic, industry and policy perspectives, challenges in implementing smaller timber dwellings, and study limitations and future research. Beyond its empirical contribution, this paper offers a practical contribution with its hierarchical data analysis approach covering building, element and component. This approach can be implemented by researchers and practitioners alike to inform their design process.","Embodied carbon; Life cycle assessment; Timber construction; Downsizing; House size; Housing","en","journal article","","","","","","","","","","","Urban Development Management","","",""
"uuid:db8a45fb-5bf5-4320-a11a-138ae5a80939","http://resolver.tudelft.nl/uuid:db8a45fb-5bf5-4320-a11a-138ae5a80939","A new numerical modelling framework for fixed oscillating water column wave energy conversion device combining BEM and CFD methods: Validation with experiments","Raghavan, V. (TU Delft Offshore Engineering); Simonetti, Irene (University of Florence); Metrikine, A. (TU Delft Hydraulic Engineering; TU Delft Engineering Structures); Lavidas, G. (TU Delft Offshore Engineering); Cappietti, Lorenzo (University of Florence)","","2024","The Oscillating Water Column (OWC) wave energy converter has been shown to have high potential, thus rendering extensive development in recent years. In order to further accelerate its development, highly accurate yet computationally efficient tools are necessary particularly when studying the interaction of multiple OWC devices. This paper proposes a new framework for fixed OWC devices with an orifice, that uses the input from a high fidelity non-linear numerical model to improve the accuracy of a low fidelity linear numerical model keeping computational costs low. This is done by accounting for the non-linearities in the pressure-flow of an orifice in the input to the linear numerical model. Experimental data is used to validate the framework, thus providing an accurate and computationally efficient linear numerical model, that can be used for the preliminary analysis of fixed OWC devices.","wave energy; computational fluid dynamic (CFD); Boundary Element Method (BEM); Oscillating Water Column; HAMS-MREL; OpenFOAM; Framework","en","journal article","","","","","","","","","","Hydraulic Engineering","Offshore Engineering","","",""
"uuid:a4085c4b-de19-4894-8c45-ea6b684bfe3c","http://resolver.tudelft.nl/uuid:a4085c4b-de19-4894-8c45-ea6b684bfe3c","Centimeter-Level Indoor Visible Light Positioning","Zhu, R. (TU Delft Embedded Systems); Van Den Abeele, Maxim (Katholieke Universiteit Leuven); Beysens, Jona (CSEM SA); Yang, J. (TU Delft Web Information Systems); Wang, Q. (TU Delft Embedded Systems)","","2024","Visible light positioning (VLP) based on the received signal strength (RSS) can leverage a dense deployment of LEDs in future lighting infrastructure to provide accurate and energy-efficient indoor positioning. However, its positioning accuracy heavily depends on the density of collected fingerprints, which is labor-intensive. In this work, we propose a data pre-processing method, including data cleaning and data augmentation, to construct reliable and dense fingerprint samples, thereby alleviating the impact of noisy samples as well as reducing labor intensity. Extensive experiments demonstrate that our proposed method achieves an average positioning error of 1.7 cm, utilizing a sparse dataset that reduces the fingerprint collection effort by 98 percent. Running a tinyML-based model for VLP on the Arduino Nano microcontroller, we also show the possibilities for deploying RSS fingerprint-based VLP systems on resource-constrained embedded devices for real-world applications.","","en","journal article","","","","","","","","2024-09-30","","","Embedded Systems","","",""
"uuid:0f81470b-a2c5-441b-af0f-ba9a2a5a1ec8","http://resolver.tudelft.nl/uuid:0f81470b-a2c5-441b-af0f-ba9a2a5a1ec8","BSc Optics","Konijnenberg, A.P. (TU Delft ImPhys/Optics); Adam, A.J.L. (TU Delft ImPhys/Adam group); Urbach, Paul (TU Delft ImPhys/Stallinga group)","","2024","This book treats optics at the level of students in the later stage of their bachelor or the beginning of their master. It is assumed that the student is familiar with Maxwell’s equations. Although the book takes account of the fact that optics is part of electromagnetism, special emphasis is put on the usefulness of approximate models of optics, their hierarchy and limits of validity. Approximate models such as geometrical optics and paraxial geometrical optics are treated extensively and applied to image formation by the human eye, the microscope and the telescope.
Polarisation states and how to manipulate them are studied using Jones vectors and Jones matrices. In the context of interference, the coherence of light is explained thoroughly. To understand fundamental limits of resolution which cannot be explained by geometrical optics, diffraction theory is applied to imaging. The angular spectrum method and evanescent waves are used to understand the inherent loss of information about subwavelength features during the propagation of light. The book ends with a study of the working principle of the laser.","geometrical optics; interferometry; diffraction optics; polarisation states; Jones vectors; coherence of light","en","book","TU Delft OPEN","978-94-6366-847-7","","","","TU Delft OPEN Textbook","","","","","ImPhys/Optics","","",""
"uuid:3eca4e81-1449-4cce-8e6c-cf8d2929d6ea","http://resolver.tudelft.nl/uuid:3eca4e81-1449-4cce-8e6c-cf8d2929d6ea","ORC Waste Heat Recovery System for the Turboshaft Engines of Turboelectric Aircraft: correction","Krempus, D. (TU Delft Flight Performance and Propulsion); Beltrame, F. (TU Delft Flight Performance and Propulsion); Majer, M. (TU Delft Flight Performance and Propulsion); Colonna, Piero (TU Delft Flight Performance and Propulsion); de Servi, C.M. (TU Delft Flight Performance and Propulsion); Vos, Roelof (TU Delft Flight Performance and Propulsion)","","2024","This paper presents a preliminary study about a combined-cycle engine based on a turboshaft engine and an organic-Rankine-cycle (ORC) bottoming unit to be used onboard an aircraft with a turboelectric propulsion system. The aim is to analyse whether benefits with respect to mission fuel consumption can be derived by employing such a combined-cycle
engine when compared to a simple-cycle turboshaft engine. For this purpose, a multidisciplinary optimization framework is developed, incorporating models for the engine, ORC system, ORC turbine, heat exchangers, and mission analysis. This framework is coupled with an optimizer to identify the optimal combined-cycle engine design for minimum mission fuel consumption. The results suggest that fuel savings of around 1.5% are possible with the optimized system if compared to the aircraft employing turboshaft engines. Heat exchanger volume is identified as the most constraining parameter when it comes to combined-cycle performance. The analysis of the results suggests as aspects which might lead to further improvements the evaluation of other ORC architectures, working fluids and heat exchanger topologies.","Organic Rankine Cycle; Waste heat recovery; Turboshaft engines; Turboelectric aircraft","en","report","","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:ae16fe71-3f56-4ee1-87dc-db4076993d4b","http://resolver.tudelft.nl/uuid:ae16fe71-3f56-4ee1-87dc-db4076993d4b","Multiscale Upscaling Study for CO2 Storage in Carbonate Rocks Using Machine Learning and Multiscale Imaging","Yong, Wen Pin (Petronas Research); Menke, Hannah (Heriot-Watt University); Maes, Julien (Heriot-Watt University); Geiger, S. (TU Delft Applied Geology); Bakar, Zainol Affendi Abu (Petronas Research); Lewis, Helen (Heriot-Watt University); Buckman, Jim (Heriot-Watt University); Bonnin, Anne (Paul Scherrer Institut); Singh, Kamaljit (Heriot-Watt University)","","2024","Microporosity is commonly assumed to be non-connected porosity and not commonly studied in geoengineering industry. However, the presence of micropores plays a key role in connecting macropores and it can contribute significantly to the overall flow performance. In this study, targeted CO2 storage carbonate fields in Southeast Asia have significant amounts of microporosity ranging from 10 to 60% of the total measured porosity. Microporosity can only be seen in high resolution images. To study the unresolved and the resolved microporosity, Middle Miocene carbonate samples from CO2 storage candidate fields were scanned using lower resolution micro-computed micro-tomography (micro-CT) and higher resolution synchrotron light source to understand the pore scale structure of the carbonate sample at different length scales. This paper proposes a proof-of-concept upscaling method that integrates multiscale 3D imaging techniques and trendline analysis to establish porosity-permeability relationships with microporosity insight. After image acquisition and processing, the images were divided into smaller sub-volumes. Pore-scale modelling was conducted to predict the permeability using Darcy-Brinkman-Stokes (DBS) model. Then, a nano-scale porosity-permeability transform is generated using natural log trendline fitting based on simulation results. The porosity-permeability transform is further extended to three cases to cover the low case, mid case, and high case of datapoint fittings and is further validated with laboratory measured data. The established porosity-permeability transforms in this study have been applied to compare with petrophysical derived porosity-permeability transforms with better performance (higher R2 value) for low permeability datapoint. The multiscale imaging upscaling workflow has integrated machine learning during image segmentation with pore-scale modelling and trendline fitting during the upscaling study. It emphasises the importance of seeing the unseen (unresolved microporous phase) to understand the internal texture and microstructure of a rock sample in order to understand the connectivity of the overall flow performance in a carbonate rock.","carbonate rock; geologist; sedimentary rock; geology; rock type; reservoir characterization; reservoir simulation; scaling method; fluid dynamics; trendline fitting","en","conference paper","Offshore Technology Conference","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-22","","","Applied Geology","","",""
"uuid:af8e2827-331c-464c-aa5f-bd6c7d1a2b96","http://resolver.tudelft.nl/uuid:af8e2827-331c-464c-aa5f-bd6c7d1a2b96","Three-Dimensional Clustering in the Characterization of Spatiotemporal Drought Dynamics: Cluster Size Filter and Drought Indicator Threshold Optimization","Diaz, Vitali (TU Delft Digital Technologies; IHE Delft Institute for Water Education); Corzo Perez, Gerald A. (IHE Delft Institute for Water Education); Van Lanen, Henny A.J. (Wageningen University & Research); Solomatine, D.P. (TU Delft Water Resources; Water Problems Institute of Russian Academy of Sciences; IHE Delft Institute for Water Education)","","2024","In its three-dimensional (3-D) characterization, drought is an event whose spatial extent changes over time. Each drought event has an onset and end time, a location, a magnitude, and a spatial trajectory. These characteristics help to analyze and describe how drought develops in space and time (i.e., drought dynamics). Methodologies for 3-D characterization of drought include a 3-D clustering technique to extract the drought events from the hydrometeorological data. The application of the clustering method yields small artifact droughts. These small clusters are removed from the analysis with the use of a cluster size filter. However, according to the literature, the filter parameters are usually set arbitrarily, so this study concentrated on a method to calculate the optimal cluster size filter for the 3-D characterization of drought. The effect of different drought indicator thresholds to calculate drought is also analyzed. The approach was tested in South America with data from the Latin American Flood and Drought Monitor for 1950–2017. Analysis of the spatial trajectories and characteristics of the most extreme droughts is also included. Calculated droughts are compared with information reported at a country scale and a reasonably good match is found.","Spatiotemporal drought analysis; Drought tracking; Drought dynamics; Drought characterization; Drought clustering","en","book chapter","AGU/Wiley","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-15","","","Digital Technologies","","",""
"uuid:a8a413df-ce92-4833-9dbd-98b07f0c1b71","http://resolver.tudelft.nl/uuid:a8a413df-ce92-4833-9dbd-98b07f0c1b71","Irradiation resistance of thermo-optical properties of zirconium diboride by 3 MeV electrons","Rønning, K.D. (Student TU Delft); Tang, Y. (TU Delft Group Tang)","","2024","Due to good thermal conductivity and thermal shock resistance, ultra-high temperature ceramics such as zirconium diboride (ZrB2) have been investigated as promising materials to be used in reusable thermal protection systems TPSs are vital to the heat balance of a spacecraft during atmospheric reentry and subsequent operation in space. Hence, the thermal and optical properties are especially critical for such applications. Meanwhile, radiation exposure in space can pose risks of degrading such material properties, especially over a prolonged mission duration. The interaction of electron radiation-which can be found in the outer Van Allen belt, with ZrB2 has not been studied previously and was chosen as the main scope of this study. An electron source of 3 MeV with different radiation exposure time was used. The response of thermo-optical properties of ZrB2 to increasing electron radiation fluences was investigated. ZrB2 samples were made through spark plasma sintering into sintered pellets and then exposed to 3 MeV electron irradiation. These ZrB2 samples were characterized by their microstructure, thermal conductivity, coefficient of thermal expansion (CTE), emittance, absorptivity, and surface roughness before and after irradiation. It was found that ZrB2’s thermo-optical properties showed high radiation resistance at these fluences, and no apparent microstructural change was observed after irradiation. However, the irradiated samples had, on average, a 29% lower surface roughness than the unirradiated samples, possibly originating from electron sputtering.","zirconium diboride; electron irradiation; thermal protection systems; thermal properties; optical properties","en","journal article","","","","","","","","","","","Group Tang","","",""
"uuid:7a7c041f-a807-4ba5-9535-206bf6615500","http://resolver.tudelft.nl/uuid:7a7c041f-a807-4ba5-9535-206bf6615500","Recommendations for accelerating open preprint peer review to improve the culture of science","Avissar-Whiting, Michele (Howard Hughes Medical Institute, Cambridge); Belliard, F. (TU Delft Scholarly Communications and Publishing); Bertozzi, Stafano M. (University of California Berkeley); Brand, Amy (Massachusetts Institute of Technology); Brown, Katherine (The Company of Biologists, Cambridge); Clément-Stoneham, Géraldine (UKRI, London); Dawson, Staphanie (ScienceOpen, Berlin); Dey, Gautam (European Molecular Biology Laboratory Heidelberg); Ecer, Daniel (Sciety/eLife, Cambridge)","","2024","AUPeer: Plea reviewsecoisnfianrmthimportant atallheadi part nglof evethelsarere scientific presenteprocess, dcorrectbut ly: traditional peer review at journals is coming under increased scrutiny for its inefficiency and lack of transparency. As preprints become more widely used and accepted, they raise the possibility of rethinking the peer-review process. Preprints are enabling new forms of peer review that have the potential to be more thorough, inclusive, and collegial than traditional journal peer review, and to thus fundamentally shift the culture of peer review toward constructive collaboration. In this Consensus View, we make a call to action to stakeholders in the community to accelerate the growing momentum of preprint sharing and provide recommendations to empower researchers to provide open and constructive peer review for preprints.","","en","journal article","","","","","","","","","","","Scholarly Communications and Publishing","","",""
"uuid:8ffa054d-e277-477a-82db-33ae46d4fec2","http://resolver.tudelft.nl/uuid:8ffa054d-e277-477a-82db-33ae46d4fec2","Damage history in composite laminates: Matrix cracks leading to delaminations","Romarís Villanueva, Javier (Student TU Delft); Kassapoglou, C. (TU Delft Group De Breuker)","","2024","Strain energy release rate calculations for various cases of delaminations emanating from matrix cracks are developed and used to predict the onset of delaminations and their growth size as a function of applied tension and shear loads in composite laminates. The method determines the matrix crack spacing, the delamination onset load, the delamination size at onset and, through the use of a newly proposed delamination resistance curve, the size of delaminations as they grow under load. The method can be applied to any symmetric laminate. Comparisons to test results in the literature for a variety of layups and materials shows very good agreement with the exception of cases where significant edge delaminations appear before delaminations caused by matrix cracks.","delamination onset; delaminations; Matrix cracks; resistance curve","en","journal article","","","","","","","","","","","Group De Breuker","","",""
"uuid:7726703f-cd0f-4d9d-8ead-c13d37e5c391","http://resolver.tudelft.nl/uuid:7726703f-cd0f-4d9d-8ead-c13d37e5c391","A discrete framework for the interpolation of Banach spaces","Lindemulder, N. (TU Delft Analysis; Karlsruhe Institut für Technologie); Lorist, E. (TU Delft Analysis)","","2024","We develop a discrete framework for the interpolation of Banach spaces, which contains the well-known real and complex interpolation methods, but also more recent methods like the Rademacher, γ- and ℓq-interpolation methods. Our framework is based on a sequential structure imposed on a Banach space, which allows us to deduce properties of interpolation methods from properties of sequential structures. Our framework has a formulation modelled after both the real and the complex interpolation methods. This enables us to extend various results, previously known only for either the real or the complex interpolation method, to all interpolation methods that fit into our framework. As applications, we prove an interpolation result for analytic operator families and an interpolation result for intersections.","Analytic operator family; Interpolation theory; Reiteration; Sequence structure","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:4a3ca713-2f5c-4934-8db0-d4b81efdc354","http://resolver.tudelft.nl/uuid:4a3ca713-2f5c-4934-8db0-d4b81efdc354","Microscopic fracture toughness of notched porous sintered Cu micro-cantilevers for power electronics packaging","Hu, D. (TU Delft Electronic Components, Technology and Materials); Du, L. (TU Delft Electronic Components, Technology and Materials); Alfreider, Markus (Montan University of Leoben); Fan, J. (TU Delft Electronic Components, Technology and Materials; Shanghai Engineering Technology Research Center for SiC Power Device; Fudan University); Kiener, Daniel (Montan University of Leoben); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2024","To fulfill the high-temperature application requirement of high-power electronics packaging, Cu nanoparticle sintering technology, with benefits in low-temperature processing and high-melting point, has attracted considerable attention as a promising candidate for the die-attach interconnect. Comprehensive mechanical characterization of the sintered layer at a microscale is necessary to deepen the understanding of the fracture behavior and improve the reliable design of materials. In this study, microscale cantilevers with different notch depths were fabricated in a 20 MPa sintered interconnect layer. Continuous dynamical fracture testing of the microcantilevers was conducted in situ in a scanning electron microscope to detail the failure characteristic of the porous sintered structure. The microscopic fracture toughness of different notched specimens was obtained from the J-integral in the frame of elastic-plastic fracture mechanics. Specimens with deeper notches presented higher resistance to crack extension, while geometry factors of notch-to-width ratio between 0.20 and 0.37 exhibited a relatively stable microscopic fracture toughness ranging from 3.2 ± 0.3 to 3.6 ± 0.1 MPa m1/2.","Continuous stiffness testing; Cu nanoparticles sintering; Elastic-plastic fracture mechanics; Microscopic fracture toughness","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:7732ecfc-1cca-4323-aa38-f49247654ac3","http://resolver.tudelft.nl/uuid:7732ecfc-1cca-4323-aa38-f49247654ac3","Fabrication of Living Entangled Network Composites Enabled by Mycelium","Wang, H. (TU Delft Aerospace Manufacturing Technologies; City University of Hong Kong); Tao, Jie (Nanjing University of Aeronautics and Astronautics); Wu, Zhangyu (Southeast University); Weiland, K.M. (TU Delft Group Masania); Wang, Zuankai (The Hong Kong Polytechnic University); Masania, K. (TU Delft Group Masania); Wang, B. (TU Delft Geo-engineering; City University of Hong Kong)","","2024","Organic polymer-based composite materials with favorable mechanical performance and functionalities are keystones to various modern industries; however, the environmental pollution stemming from their processing poses a great challenge. In this study, by finding an autonomous phase separating ability of fungal mycelium, a new material fabrication approach is introduced that leverages such biological metabolism-driven, mycelial growth-induced phase separation to bypass high-energy cost and labor-intensive synthetic methods. The resulting self-regenerative composites, featuring an entangled network structure of mycelium and assembled organic polymers, exhibit remarkable self-healing properties, being capable of reversing complete separation and restoring ≈90% of the original strength. These composites further show exceptional mechanical strength, with a high specific strength of 8.15 MPa g.cm−3, and low water absorption properties (≈33% after 15 days of immersion). This approach spearheads the development of state-of-the-art living composites, which directly utilize bioactive materials to “self-grow” into materials endowed with exceptional mechanical and functional properties.","living composites; mechanical properties; mycelium; phase separation","en","journal article","","","","","","","","","","","Aerospace Manufacturing Technologies","","",""
"uuid:f01cdc5a-a57a-466f-a5bc-a9f7fa796f07","http://resolver.tudelft.nl/uuid:f01cdc5a-a57a-466f-a5bc-a9f7fa796f07","Comparative assessment of generative models for transformer- and consumer-level load profiles generation","Xia, W. (TU Delft Intelligent Electrical Power Grids); Huang, Hanyue (Technische Universität München); Duque, Edgar Mauricio Salazar (Eindhoven University of Technology); Shengren, H. (TU Delft Intelligent Electrical Power Grids); Palensky, P. (TU Delft Electrical Sustainable Energy); Vergara Barrios, P.P. (TU Delft Intelligent Electrical Power Grids)","","2024","Residential load profiles (RLPs) play an increasingly important role in the optimal operation and planning of distribution systems, particularly with the rising integration of low-carbon energy resources such as PV systems, electric vehicles, small-scale batteries, etc. Despite the prevalence of various data-driven models for generating consumption profiles, there is a lack of clear conclusions about their relative strengths and weaknesses. This study undertakes a comprehensive comparison of frequently used data-driven models in recent research, including Generative Adversarial Networks (GANs), Variational Autoencoders (VAE), Wasserstein GANs (WGAN), WGANs with Gradient Penalty (WGANGP), Gaussian Mixture Models (GMMs), and Gaussian Mixture Copulas (GMC). The presented comparison explores the effectiveness of the above-mentioned models on transformer- and consumer-level consumption profiles, as well as for different time resolutions (15-min, 30-min, and 60-min). The objective of this research is to elucidate the respective advantages and drawbacks of these models, thereby providing valuable insights for subsequent research in this field.","Consumption profiles; Distribution network; Generative adversarial networks; Generative models","en","journal article","","","","","","","","","","Electrical Sustainable Energy","Intelligent Electrical Power Grids","","",""
"uuid:39b1298f-64f9-4a1a-89ba-b2e62a405f9f","http://resolver.tudelft.nl/uuid:39b1298f-64f9-4a1a-89ba-b2e62a405f9f","Repeated failures of the giant Beshkiol Landslide and their impact on the long-term Naryn Basin floodings, Kyrgyz Tien Shan","Losen, J. (Aix Marseille Université); Rizza, M. (Université du Québec à Montréal; Aix Marseille Université); Nutz, A. (Aix Marseille Université); Henriquet, M. (TU Delft Astrodynamics & Space Missions; Aix Marseille Université); Schuster, M.S. (TU Delft Control & Simulation; Institut Terre et Environnement de Strasbourg (ITES)); Rakhmedinov, E. (National Academy of Sciences of the Kyrgyz Republic); Baikulov, S. (National Academy of Sciences of the Kyrgyz Republic); Abdrakhmatov, K. (National Academy of Sciences of the Kyrgyz Republic); Fleury, J. (Aix Marseille Université); Siame, L. (Aix Marseille Université)","","2024","Landslides are major hazards that lead to cataclysmic changes in regional physiography. Their consequences are particularly significant when they affect a river system, forming dammed-lake upstream that represents a high flood threat for the downstream region. The Naryn River is the largest river in the Kyrgyz Tien Shan and is of great economic importance. The Beshkiol Landslide, the largest one in Central Asia but of unknown age, has most likely blocked the Naryn River in the past during the Late Pleistocene, with evidence of thick lacustrine deposits as well as numerous paleo-shorelines preserved upstream. In this study, a detailed geomorphological and sedimentological analysis combined with luminescence and 14C dating provides a strong chronological framework to refine the dynamics between the Beshkiol landslides and dammed-lakes in the Naryn Basin. We propose that the Beshkiol Landslide was first triggered 51.9 ± 4.4 kyrs ago, with a 410 m-high dam that blocked the Naryn River. A first lake with a total volume of 121 ± 50 km3 lasted for >37.0 ± 5.1 kyrs, one of the longest landslide-dammed lake residence time ever documented in the world. Our sedimentological observations highlight a catastrophic lake outburst flood between 15.6 and 14.1 kyrs cal BP, likely related to a landslide dam breach. A short-lived phase of fluvial erosion impacted the whole Naryn Basin followed by a second landslide activation (280 m- high dam) and subsequent flooding by a second lake of 27 ± 10 km3. This second lake had a minimum residence time of 7.7 ± 1.3 kyrs before its final gradual drainage that was followed by a fluvial erosional phase still active today in the Naryn Basin. We also suggest that the distal unconsolidated part of the Beshkiol Landslide could be remobilized in the event of an earthquake and/or extreme rain episode, causing a potentially dam of the Naryn River, which would have strong regional economic impacts.","Dammed-lake; Kyrgyzstan; Landslide; Quaternary dating","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-09","","","Astrodynamics & Space Missions","","",""
"uuid:07c3a293-bac3-4cdd-80dc-17daf12fde2d","http://resolver.tudelft.nl/uuid:07c3a293-bac3-4cdd-80dc-17daf12fde2d","Multiplayer boycotts in convex games","Fokkink, R.J. (TU Delft Applied Probability); de Munnik, J.C. (TU Delft Delft Institute of Applied Mathematics; TU Delft Electrical Engineering, Mathematics and Computer Science)","","2024","We extend the notion of boycotts between players in cooperative games to boycotts between coalitions. We prove that convex games offer a proper setting for studying these games. Boycotts have a heterogeneous effect. Individual players that are targeted by many-on-one boycotts suffer most, while non-participating players may actually benefit from a boycott.","Cooperative games; Impact of boycotts; Shapley value","en","journal article","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","Applied Probability","","",""
"uuid:0b54ffe2-f0a7-44d6-87da-5cbefcbc428f","http://resolver.tudelft.nl/uuid:0b54ffe2-f0a7-44d6-87da-5cbefcbc428f","The modulus of a vector measure","de Pagter, B. (TU Delft Analysis); Ricker, Werner J. (Katholische Universität Eichstätt - Ingolstadt)","","2024","It is known that if L is a Dedekind complete Riesz space and (Ω, Σ) is a measurable space, then the partially ordered linear space of all L-valued, finitely additive and order bounded vector measures m on Σ is also a Dedekind complete Riesz space (for the natural operations). In particular, the modulus |m|o of m exists in this space of measures and |m|o is given by a well known formula. Some 20 years ago L. Drewnowski and W. Wnuk asked the question (for L not Dedekind complete) if there is an m for which |m|o exists but, |m|o is not given by the usual formula? We show that such a measure m does indeed exist.","finitely additive; modulus; order bounded; Vector measure","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-09","","","Analysis","","",""
"uuid:9a8d0ef5-3ea1-41c8-abac-ee1241579348","http://resolver.tudelft.nl/uuid:9a8d0ef5-3ea1-41c8-abac-ee1241579348","A Parametric Modelling Approach for Energy Retrofitting Heritage Buildings: The Case of Amsterdam City Centre","Dang, M.K. (TU Delft Environmental & Climate Design; TU Delft Amsterdam Institute for Advanced Metropolitan Solutions); van den Dobbelsteen, A.A.J.F. (TU Delft Environmental & Climate Design; TU Delft Amsterdam Institute for Advanced Metropolitan Solutions); Voskuilen, P.C. (TU Delft Amsterdam Institute for Advanced Metropolitan Solutions)","","2024","The city of Amsterdam has ambitious goals to achieve a 95% reduction in carbon emissions by 2050 and to phase out natural gas by 2040. Disconnecting the building stock from natural gas requires well-ventilated and well-insulated buildings and a switch to renewable energy sources, making optimal use of heat pumps and sustainable heating solutions available locally. Most buildings in the historical city centre are protected and often insufficiently insulated, leading to increased energy use and a poor thermal environment. Standard retrofitting interventions may be restricted, requiring new approaches to balancing the need for energy efficiency and the preservation of heritage significance. With the case of the Amsterdam City Centre, the goal of this research is to present a parametric modelling approach for energy retrofitting heritage buildings and to identify minimum requirements for preparing the residential stock to lower temperature heat (LTH). Using parametric design and bottom-up energy modelling, the research estimates that a 69.1% of natural gas reduction could be achieved when upgrading the buildings to lower temperature (LT). Results of this paper also demonstrate how the applied approach can be used to guide decisions on the improvement in energy performance of the historic built environment.","built heritage; energy retrofitting; parametric modelling; simulation; low-temperature heating","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:9f4bd225-420d-4992-8ca5-ce02144a738b","http://resolver.tudelft.nl/uuid:9f4bd225-420d-4992-8ca5-ce02144a738b","Decentralized multi-agent path finding framework and strategies based on automated negotiation","Keskin, M. Onur (Özyeğin University); Cantürk, Furkan (Özyeğin University); Eran, Cihan (Özyeğin University); Aydoğan, Reyhan (TU Delft Interactive Intelligence; Özyeğin University)","","2024","This paper introduces a negotiation framework to solve the Multi-Agent Path Finding (MAPF) Problem for self-interested agents in a decentralized fashion. The framework aims to achieve a good trade-off between the privacy of the agents and the effectiveness of solutions. Accordingly, a token-based bilateral negotiation protocol and two negotiation strategies are presented. The experimental results over four different settings of the MAPF problem show that the proposed approach could find conflict-free path solutions albeit suboptimally, especially when the search space is large and high-density. In contrast, Explicit Estimation Conflict-Based Search (EECBS) struggles to find optimal solutions. Besides, deploying a sophisticated negotiation strategy that utilizes information about local density for generating alternative paths can yield remarkably better solution performance in this negotiation framework.","Decentralized coordination; Multi-agent path finding; Negotiation","en","journal article","","","","","","","","","","","Interactive Intelligence","","",""
"uuid:96b17a56-bc51-47f5-aece-4d1774482d5c","http://resolver.tudelft.nl/uuid:96b17a56-bc51-47f5-aece-4d1774482d5c","Towards reusable building blocks for agent-based modelling and theory development","Berger, Uta (Technische Universität Dresden); Bell, Andrew (Boston University); Barton, C. Michael (Arizona State University); Chappin, E.J.L. (TU Delft Energie and Industrie); Dreßler, Gunnar (Helmholtz Centre for Environmental Research - UFZ); Filatova, T. (TU Delft Policy Analysis); Fronville, Thibault; Lee, Allen (Arizona State University); van Loon, Emiel (Universiteit van Amsterdam); Lorscheid, Iris; Meyer, Matthias (Hamburg University of Technology); Müller, Birgit (Helmholtz Centre for Environmental Research - UFZ; BTU Cottbus-Senftenberg); Piou, Cyril (CIRAD); Radchuk, Viktoriia (Leibniz Institute for Zoo and Wildlife Research); Roxburgh, Nicholas (The James Hutton Institute); Schüler, Lennart (Helmholtz Centre for Environmental Research - UFZ); Troost, Christian (University of Hohenheim); Wijermans, Nanda (Stockholm University); Williams, Tim G. (Vrije Universiteit Amsterdam); Wimmler, Marie Christin (Technische Universität Dresden); Grimm, Volker (Helmholtz Centre for Environmental Research - UFZ)","","2024","Despite the increasing use of standards for documenting and testing agent-based models (ABMs) and sharing of open access code, most ABMs are still developed from scratch. This is not only inefficient, but also leads to ad hoc and often inconsistent implementations of the same theories in computational code and delays progress in the exploration of the functioning of complex social-ecological systems (SES). We argue that reusable building blocks (RBBs) known from professional software development can mitigate these issues. An RBB is a submodel that represents a particular mechanism or process that is relevant across many ABMs in an application domain, such as plant competition in vegetation models, or reinforcement learning in a behavioural model. RBBs need to be distinguished from modules, which represent entire subsystems and include more than one mechanism and process. While linking modules faces the same challenges as integrating different models in general, RBBs are “atomic” enough to be more easily re-used in different contexts. We describe and provide examples from different domains for how and why building blocks are used in software development, and the benefits of doing so for the ABM community and to individual modellers. We propose a template to guide the development and publication of RBBs and provide example RBBs that use this template. Most importantly, we propose and initiate a strategy for community-based development, sharing and use of RBBs. Individual modellers can have a much greater impact in their field with an RBB than with a single paper, while the community will benefit from increased coherence, facilitating the development of theory for both the behaviour of agents and the systems they form. We invite peers to upload and share their RBBs via our website - preferably referenced by a DOI (digital object identifier obtained e.g. via Zenodo). After a critical mass of candidate RBBs has accumulated, feedback and discussion can take place and both the template and the scope of the envisioned platform can be improved.","Best practices; Complex adaptive systems; Individual-based modelling; Software engineering; Theory development","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:373b104d-01b8-4a4f-99f5-b432aa23add6","http://resolver.tudelft.nl/uuid:373b104d-01b8-4a4f-99f5-b432aa23add6","Do network management and trust matter for network outcomes? A meta-analysis and research agenda","George, Bert (City University of Hong Kong); Klijn, Erik Hans (Erasmus Universiteit Rotterdam); Ropes, Emma (Erasmus Universiteit Rotterdam); Sattlegger, A.S. (TU Delft Information and Communication Technology)","","2024","Collaborative and network governance assume that network management and trust matter for network outcomes. We test this assumption by conducting a meta-analysis of public administration studies investigating the correlation between network management and network outcomes (50 effect sizes), and trust and network outcomes (28 effect sizes). While both matter for achieving network outcomes across countries, trust matters most. Trust is particularly important for achieving process outcomes and multiple network management strategies combined are more effective than separate single strategies. A research agenda centred on complex modelling, comparative research and using mixed, multisource, experimental and longitudinal data is stipulated in conclusion.","meta-analysis; Network management; network outcomes; network performance; network trust","en","journal article","","","","","","","","","","","Information and Communication Technology","","",""
"uuid:e6f5e9f2-75f1-487b-b993-03b266bfae32","http://resolver.tudelft.nl/uuid:e6f5e9f2-75f1-487b-b993-03b266bfae32","Long distance accessibility by air transportation: a literature review","Yoo, Sihyun (TU Delft Transport and Logistics); van Wee, G.P. (TU Delft Transport and Logistics); Molin, E.J.E. (TU Delft Transport and Logistics)","","2024","Air transportation is a mode of transport developed specifically to provide access to long-distance destinations that may otherwise be infeasible or at least more difficult to reach. Accordingly, there are distinct aspects of air travel that require consideration when assessing accessibility by air transportation, which are not addressed in general local accessibility studies. This paper reviews studies of accessibility by air transportation. The studies in question were published in academic journals, and we analysed them using the broad theoretical framework of accessibility of Geurs and van Wee [Accessibility evaluation of land-use and transport strategies: Review and research directions. Journal of Transport Geography, 12(2), 127–140]. We discuss the characteristics of accessibility by air transportation to consider when designing research, as well as trends and knowledge gaps in the existing literature. An important gap is that, while there is a growing interest towards perceived accessibility by air transportation, accessibility measures based on this perspective have not yet been applied yet. Additionally, the literature is largely focused on the transport and land-use components of accessibility as opposed to the individual and temporal components. We finish by discussing the benefits and drawbacks of directly applying conventional accessibility measures for research on accessibility by air transportation, as well as options to modify the temporal component of conventional person-based accessibility measures for better applicability in the air travel context.","Accessibility; accessibility review; air transportation; literature review; long distance accessibility","en","journal article","","","","","","","","","","","Transport and Logistics","","",""
"uuid:ff27c9ae-ac49-458f-a738-976217c6d3db","http://resolver.tudelft.nl/uuid:ff27c9ae-ac49-458f-a738-976217c6d3db","Understanding the embeddedness of individuals within the larger system to support energy transition","Biely, Katharina (Wageningen University & Research); Sareen, Siddharth (University of Stavanger; University of Bergen); de Vries, G. (TU Delft Organisation & Governance); Chappin, E.J.L. (TU Delft Energie and Industrie); Bauwens, Thomas (Erasmus Universiteit Rotterdam); Montagnino, Fabio Maria (The Cyprus Insitute)","","2024","CO2 emissions need to be reduced drastically to fight climate change and minimise the further increase of average global temperatures. The decarbonisation of the energy system aims at reducing CO2 emissions and is thus urgently needed. This transition is facilitated by inter alia switching to renewable energy sources and more efficient technologies. In the past, the energy transition has mostly focused on supply-side measures. However, at least since the publication of the 6th IPCC assessment report, demand-side measures have gained attention. Thereby, the roles individuals play in achieving this transition is recognised as important. This Special Feature is dedicated to exploring the roles of individuals within the energy transition. The nine thematically featured articles provide insights on this topic using different foci and angles, such as the information to guide individuals' behaviour, the influence of media in framing roles, and technology acceptance. To contextualise and synthesise these diverse contributions, this editorial introduction outlines three different, complementary clusters of roles: technology adoption, lifestyle choices, and political action. By theorising users as participants in transitions through diverse practices, we widen the basis for future research to address and incorporate the roles users play in engaging with and shaping these transitions.","Agency; Energy citizenship; Energy transition; Low-carbon lifestyle; Technology adoption","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-13","","","Organisation & Governance","","",""
"uuid:14f95d54-4113-4225-a040-79c35dbc0714","http://resolver.tudelft.nl/uuid:14f95d54-4113-4225-a040-79c35dbc0714","Longitudinal analysis of interorganizational collaborative networks of cross-laminated timber (CLT) construction","Said, Hisham (Santa Clara University); Rajagopalan, Aswathy (Santa Clara University); Hall, Daniel M. (TU Delft Design & Construction Management)","","2024","Purpose
Cross-laminated timber (CLT) is an innovative construction material that provides a balanced mix of structural stiffness, fabrication flexibility and sustainability. CLT development and innovation diffusion require close collaborations between its supply chain architectural, engineering, construction and manufacturing (AECM) stakeholders. As such, the purpose of this study is to provide a preliminary understanding of the knowledge diffusion and innovation process of CLT construction.
Design/methodology/approach
The study implemented a longitudinal social network analysis of the AECM companies involved in 100 CLT projects in the UK. The project data were acquired from an industry publication and decoded in the form of a multimode project-company network, which was projected into a single-mode company collaborative network. This complete network was filtered into a four-phase network to allow the longitudinal analysis of the CLT collaborations over time. A set of network and node social network analysis metrics was used to characterize the topology patters of the network and the centrality of the companies.
Findings
The study highlighted the scale-free structure of the CLT collaborative network that depends on the influential hubs of timber manufacturers, engineers and contractors to accelerate the innovation diffusion. However, such CLT supply collaborative network structure is more vulnerable to disruptions due to its dependence on these few prominent hubs. Also, the industry collaborative network’s decreased modularity confirms the maturity of the CLT technology and the formation of cohesive clusters of innovation partners. The macro analysis approach of the study highlighted the critical role of supply chain upstream stakeholders due to their higher centralities in the collaborative network. Stronger collaborations were found between the supply chain upstream stakeholders (timber manufacturers) and downstream stakeholders (architects and main contractors).
Originality/value
The study contributes to the field of industrialized and CLT construction by characterizing the collaborative networks between CLT supply chain stakeholders that are critical to propose governmental policies and industry initiatives to advance this sustainable construction material.","knowledge management; innovation; social network analysis; supply chain management; organizational learning; construction technology","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-11","","","Design & Construction Management","","",""
"uuid:858857a1-0023-404a-89ab-92cd337667e6","http://resolver.tudelft.nl/uuid:858857a1-0023-404a-89ab-92cd337667e6","Correction to: Ballistic Majorana nanowire devices (Nature Nanotechnology, (2018), 13, 3, (192-197), 10.1038/s41565-017-0032-8)","Gül, Önder (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Zhang, H. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bommer, J.D.S. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); de Moor, M.W.A. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Car, Diana (Eindhoven University of Technology); Plissard, Sébastien R. (Eindhoven University of Technology; Université de Toulouse); Bakkers, E.P.A.M. (TU Delft QN/Bakkers Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Eindhoven University of Technology); Geresdi, A. (TU Delft QRD/Geresdi Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Microsoft Quantum Lab Delft)","","2024","Correction to: Nature Nanotechnologyhttps://doi.org/10.1038/s41565-017-0032-8, published online 15 January 2018. The Letter reports Majorana signatures in hybrid InSb semiconductor nanowire–NbTiN superconductor devices. The devices exhibit a conductance plateau near the conductance quantum 2e2/h at bias voltages above the superconducting gap (normal conductance), accompanied by an enhanced Andreev conductance at bias voltages below the superconducting gap (subgap conductance). We have attributed these experimental observations to ballistic transport as supported by a theoretical analysis1, finding mean free paths on the order of or larger than the effective wire segment (the segment covered by the superconducting electrode). Here, we correct errors discovered on reanalysis of the original data2, following concerns raised by readers. Due to the age of the paper, it cannot be corrected directly in the original publication, thus the updates are provided via this amendment. We provide additional discussion on the claim of ballistic transport so as to avoid misinterpretations. External peer review of the reanalysis concluded that the claims in the Letter remain. An extended public repository including data obtained from nanowire devices that were not included in the publication can be found in ref. 2. We note the lack of a series of flat and precisely quantized conductance plateaus (a staircase), a clear ballistic transport characteristic (see the two newly included Supplementary Figs. 1 and 7 showing larger voltage ranges of Fig. 1 and the original Supplementary Fig. 5). Our earlier studies on ballistic transport in nanowire devices3,4 indicate that vapour–liquid–solid nanowires do not have the proper geometry for observing a conductance staircase without the application of a magnetic field perpendicular to the wire axis, which requires ideal (Landauer) reservoirs interfacing the ballistic region, absorbing charge carriers with near-unit probability. Similar to our earlier studies, ohmic contacts in the present nanowire devices do not satisfy the conditions of Landauer reservoirs. However, the transport in the effective wire segment can nevertheless be ballistic whose characteristic is a plateau feature near 2e2/h in normal conductance together with an enhanced Andreev conductance. Importantly, precise quantization is not realistic, prevented by the two-terminal device geometry, inevitably decreasing the conductance. In summary, a plateau feature with an enhanced Andreev conductance together with our theoretical analyses indicate that a large fraction of transport is ballistic over distances of the order of our device length. We add a discussion to the main text of the Letter as follows: “… followed by a dip in conductance due to channel mixing20 [ref. 1 below]. We do not observe higher plateaus (Supplementary Figs. 1 and 7), which we attribute to the contacts not satisfying the conditions of Landauer reservoirs, resulting in residual scattering more effective at larger conductance. This is in line with our earlier studies25,39 [refs. 4,5 below] which indicated that vapour–liquid–solid nanowires do not have the proper geometry for observing a conductance staircase without the application of a perpendicular magnetic field. From the absence of quantum dots, the observed induced gap …”. The following text should also have been included in the abstract: “… exhibiting clear ballistic transport properties manifested by a conductance plateau with an Andreev enhancement, albeit lacking a quantized conductance staircase hindered by the device geometry.” The conductance values reported in the publication are ~8% lower (near 2e2/h) than the actual value (corrected Fig. 1). This deviation is due to a drop in the gain of the current-to-voltage amplifier at an ac excitation frequency of 67 Hz5. As a result, there is a slight change in the Andreev conductance enhancement factor and the superconducting contact transparency extracted from the enhancement (a comparison between the values quoted in the publication and the corrected ones is given below in B). The general conclusions do not rely on the exact value of the conductance as precise quantization is not expected due to the two-terminal device geometry. The subtracted series resistance of 3 kΩ in the original Fig. 1 was an overestimation (see corrected Fig. 1 in the Supplementary Data file). The subtraction of 3 kΩ was not mentioned in the original publication. A comparison of the original and corrected Fig. 1 is presented in a Supplementary Data file accompanying this correction. For all the figures in the original publication except Fig. 1, we either subtracted a contact resistance value of 0.5 kΩ, which is an underestimation1, or no resistance at all. We note that in tunneling measurements the overall resistance is significantly higher than the normal metal contact resistance whose contribution can therefore be neglected. Figure 1, however, was used to estimate the superconducting contact transparency and Andreev enhancement in the high conductance regime, requiring a realistic exclusion of the contact resistance. Following our previous paper4, which found normal metal contact resistance values between 1.5–3.25 kΩ per contact and was based on fitting the measured conductance using theory (single mode interfacing a superconductor), which provided reasonable agreement after excluding 3 kΩ, we subtracted 3 kΩ to exclude the resistance of the normal metal contact. During our reanalysis, we have discovered that the minimum resistance of this device at the largest applied gate voltages is 2.9 kΩ, a value providing an upper bound on the contact resistance. Here, 2.9 kΩ would be the contact resistance under the assumption that the nanowire itself has zero resistance at largest gate voltages. The contact resistance can be estimated with an alternative method by subtracting a series resistance to match the observed conductance plateau at bias voltages above the superconducting gap to the expected quantized value, a procedure not done in the original publication. By taking the conductance averaged at positive and negative |V| ~ 1.7 mV (around the largest bias voltages available for this analysis) we find that the quantized value is reached for a contact resistance of 0.77 kΩ. (Considering only the positive bias and separately only the negative bias results in a range of 0–2.13 kΩ for the contact resistance.) In our corrected estimate of the contact resistance, we have applied the calibration procedure5 that corrects for ac circuit effects, uses calibrated values for the series resistance of the setup where Fig. 1 was measured and directly corrects the error listed in A above. Upon reanalysis we estimate the following contact resistance values, enhancement factors and transparencies: (Table presented.) Contact resistance Enhancement factor Transparency Lower bound 0 kΩ 1.26 0.88 Conservative estimation1 (used in corrected Fig. 1) 0.5 kΩ 1.32 0.90 Current best estimate 0.77 kΩ 1.36 0.90 Original estimate in paper 3 kΩ >1.5 >0.93 The corrected superconducting contact transparency value of 0.9 does not affect the claim of high transparency. The claim of ballistic transport does not rest on the exact value of the conductance plateau and hence is also unaffected. The original Methods section omits the indication of subtracted series resistances which account for the normal metal contact resistance in each figure. The following is included here for the corrected Methods: The original Methods section omits the indication of subtracted series resistances which account for the normal metal contact resistance in each figure. The following is included here for the corrected Methods: “Contact resistance treatment. A fixed-value series resistance of 0.5 kΩ has been subtracted in Figs. 1 and 4, Supplementary Figs. 1, 2b,c and 4–9 to account for the contact resistance of the normal metal lead. This value is smaller than the lowest contact resistance we have obtained for InSb nanowire devices25 (ref. 4 below), which makes the interface transparency estimated from Fig. 1 a lower bound. For the remaining figures, no series resistance has been subtracted to account for the normal metal contact resistance.” In the original Supplementary Fig. 5 (now Supplementary Fig. 6), a charge jump was corrected by removal of 12 line traces (corresponding to +0.15 V to +0.04 V in gate voltage in the measured data) and offset of the gate voltage axis by 0.12 V after the charge jump (–1 V to +0.03 V) to maintain continuity of the axis. This processing was not mentioned in the original publication. The corrected Supplementary Fig. 6 excludes this processing and represents the data as measured. In the original Supplementary Fig. 5 (now Supplementary Fig. 6), a charge jump was corrected by removal of 12 line traces (corresponding to +0.15 V to +0.04 V in gate voltage in the measured data) and offset of the gate voltage axis by 0.12 V after the charge jump (–1 V to +0.03 V) to maintain continuity of the axis. This processing was not mentioned in the original publication. The corrected Supplementary Fig. 6 excludes this processing and represents the data as measured. A comparison of the original and corrected Fig. SI5 (now Fig. SI6) is presented in a Supplementary Data file accompanying this correction. Original Supplementary Fig. 1f (now Supplementary Fig. 2f): The offset mentioned in the caption is erroneously given as 0.006 × 2e2/h but is 0.01 × 2e2/h. Original Supplementary Fig. 4a,b (now Supplementary Fig. 5a,b) were indicated to present data from Fig. 2a (or original Supplementary Fig. 1a). This is incorrect. The data used are from the original Supplementary Fig. 1b (now Supplementary Fig. 2b) which has the same measurement settings as in Fig. 2a except the barrier gate is –1.5 V (the barrier gate is –1.4 V in Fig. 2a or original Supplementary Fig. 1a). In the original panels c–e of Supplementary Fig. 7 (now Supplementary Fig. 9c–e) the bias polarity is mistakenly inverted.","","en","journal article","","","","","","Corrigendum DOI 10.1038/s41565-0170032-8 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-11","","","QRD/Kouwenhoven Lab","","",""
"uuid:888a8ad0-fd2f-4d82-86ed-dfb7f0397d2a","http://resolver.tudelft.nl/uuid:888a8ad0-fd2f-4d82-86ed-dfb7f0397d2a","Challenges and opportunities for process intensification in Europe from a process systems engineering perspective","Li, Q. (TU Delft ChemE/Process Systems Engineering); Somoza Tornos, A. (TU Delft ChemE/Process Systems Engineering); Grievink, J. (TU Delft ChemE/Product and Process Engineering); Kiss, A.A. (TU Delft ChemE/Process Systems Engineering)","","2024","Process Intensification (PI) is an effective way to enhance process efficiency and sustainability at affordable costs and efforts, attracting particular interest in the European area, as one of the most important chemical production areas in the world. PI primarily contributes by developing and testing new processing technologies that once integrated within a process improve the overall process performance substantially but as a result, it may alter the overall process (flowsheet) structure and its dynamic behavior. As such PI plays a key role in improving energy efficiency, optimizing resource allocation, and reducing environmental impact of industrial processes, and thereby leading to a cost-effective, eco-efficient, low-carbon and sustainable industry. However, along with opportunities, the PI new technologies have challenges related to failures in longer-term performance. In this respect, Process Systems Engineering (PSE) stance is more on integration aspects of new PI technologies into processes by making process (re)designs, doing operability studies, and performance optimizations within a supply chain setting. PSE contributes to overcoming the challenges by providing systematic approaches for the design and optimization of PI technologies. This perspective paper is a lightly referenced scholarly opinion piece about the status and directions of process intensification field from a PSE viewpoint. Primarily, it focuses on PSE perspectives towards sustainable lower energy usage process systems and provides a brief overview of the current situation in Europe. It also emphasizes the key challenges and opportunities for (new) PI technologies considering their integration in a process in terms of process synthesis and design, process flowsheet optimization, process and plantwide control, (green) electrification, sustainability improvements. Potential research directions on these aspects are given from an industrial and academic perspective of the authors.","ecoefficiency; energy efficiency; fluid separation; process intensification; process systems engineering","en","journal article","","","","","","","","","","","ChemE/Process Systems Engineering","","",""
"uuid:3150902c-b135-4343-b3aa-57b585946d34","http://resolver.tudelft.nl/uuid:3150902c-b135-4343-b3aa-57b585946d34","Norming and dense sets of extreme points of the unit ball in spaces of bounded Lipschitz functions","Hille, Sander C. (Universiteit Leiden); Theewis, E.S. (TU Delft Analysis)","","2024","On spaces of finite signed Borel measures on a metric space one has introduced the Fortet-Mourier and Dudley norms, by embedding the measures into the dual space of the Banach space of bounded Lipschitz functions, equipped with different – but equivalent – norms: the FM-norm and the BL-norm, respectively. The norm of such a measure is then obtained by maximising the value of the measure when applied by integration to extremal functions of the unit ball. We introduce Lipschitz extension operators, essentially based on those defined by McShane, and investigate their properties. A remarkable one is that non-trivial extreme points are mapped to non-trivial extreme points of FM- and BL-norm unit balls. Using these extension operators, we define suitable ‘small’ subsets of extremal functions that are weak-star dense in the full set of extreme points of the unit ball, for any underlying metric space. For connected metric spaces, we additionally find a larger set of extremal functions for the BL-norm, similar to such a set that was defined previously by J. Johnson for the FM-norm. This set is then also weak-star dense in the extremal functions. These results may open an avenue to obtaining computational approaches for the Dudley norm on signed Borel measures.","Extreme points; Unit ball; Lipschitz functions; Norming sets; Metric analysis","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:75b47724-a226-4fe9-82ca-4b5824df1810","http://resolver.tudelft.nl/uuid:75b47724-a226-4fe9-82ca-4b5824df1810","Structural and magnetic properties of YNi4-xCoxSi alloys","Gai, H. (TU Delft RST/Fundamental Aspects of Materials and Energy); van Dijk, N.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); Brück, E.H. (TU Delft RST/Fundamental Aspects of Materials and Energy)","","2024","The transition-metal based alloy system YNi 4-xCo xSi shows a second-order ferromagnetic-to-paramagnetic transition near room temperature. Here, the magnetic structure, the magnetocaloric properties and the magnetic anisotropy of YNi 4-xCo xSi (x = 0–4) are investigated. For x = 3.5, 3.75 and 4.0 a Curie temperature near room temperature is observed with T C = 250, 283 and 310 K, respectively. In orientated YNi 4-xCo xSi powder samples the c axis of the hexagonal crystal structure is found to be the easy magnetic axis, with a large dominant K 2 anisotropy constant (K 2 > K 1 > 0). The magnetic structure and the preferred atomic position for Ni are demonstrated by neutron diffraction measurements. We have found a dramatic decrease in the magnetic moment at the 3 g site in the CaCu 5-type structure (space group P6/mmm), the saturation magnetization and the Curie temperature with increasing Ni concentration.","","en","journal article","","","","","","","","","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:99e01587-21a2-4d19-87ec-366f3d3b9b8d","http://resolver.tudelft.nl/uuid:99e01587-21a2-4d19-87ec-366f3d3b9b8d","Designing lithium halide solid electrolytes","Wang, Q. (TU Delft RST/Storage of Electrochemical Energy); Zhou, Yunan (Tsinghua University); Wang, Xuelong (Brookhaven National Laboratory); Guo, Hao (China Institute of Atomic Energy); Gong, Shuiping (Shanghai Jiao Tong University); Yao, Zhenpeng (Shanghai Jiao Tong University); Ganapathy, S. (TU Delft RST/Storage of Electrochemical Energy; TU Delft RID/TS/Instrumenten groep); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2024","All-solid-state lithium batteries have attracted widespread attention for next-generation energy storage, potentially providing enhanced safety and cycling stability. The performance of such batteries relies on solid electrolyte materials; hence many structures/phases are being investigated with increasing compositional complexity. Among the various solid electrolytes, lithium halides show promising ionic conductivity and cathode compatibility, however, there are no effective guidelines when moving toward complex compositions that go beyond ab-initio modeling. Here, we show that ionic potential, the ratio of charge number and ion radius, can effectively capture the key interactions within halide materials, making it possible to guide the design of the representative crystal structures. This is demonstrated by the preparation of a family of complex layered halides that combine an enhanced conductivity with a favorable isometric morphology, induced by the high configurational entropy. This work provides insights into the characteristics of complex halide phases and presents a methodology for designing solid materials.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:e43792be-e3d8-4f44-a780-a1b1c40370af","http://resolver.tudelft.nl/uuid:e43792be-e3d8-4f44-a780-a1b1c40370af","Near-infrared light-driven asymmetric photolytic reduction of ketone using inorganic-enzyme hybrid biocatalyst","Qiao, Li (Hangzhou Normal University); Zhang, Jing (Hangzhou Normal University); Jiang, Yongjian (Hangzhou Normal University); Ma, Bianqin (Hangzhou Normal University); Chen, Haomin (Hangzhou Normal University); Gao, Peng (Hangzhou Normal University); Zhang, Pengfei (Hangzhou Normal University); Wang, Anming (Hangzhou Normal University); Sheldon, R.A. (TU Delft BT/Biocatalysis; University of Witwatersrand)","","2024","Effective photolytic regeneration of the NAD(P)H cofactor in enzymatic reductions is an important and elusive goal in biocatalysis. It can, in principle, be achieved using a near-infrared light (NIR) driven artificial photosynthesis system employing H2O as the sacrificial reductant. To this end we utilized TiO2/reduced graphene quantum dots (r-GQDs), combined with a novel rhodium electron mediator, to continuously supply NADPH in situ for aldo-keto reductase (AKR) mediated asymmetric reductions under NIR irradiation. This upconversion system, in which the Ti-O-C bonds formed between r-GQDs and TiO2 enabled efficient interfacial charge transfer, was able to regenerate NADPH efficiently in 64 % yield in 105 min. Based on this, the pharmaceutical intermediate (R)-1-(3,5-bis(trifluoromethyl)phenyl)ethan-1-ol was obtained, in 84 % yield and 99.98 % ee, by reduction of the corresponding ketone. The photo-enzymatic system is recyclable with a polymeric electron mediator, which maintained 66 % of its original catalytic efficiency and excellent enantioselectivity (99.9 % ee) after 6 cycles.","Aldo-ketone reductase; Cofactor regeneration; Ketone reduction; Photo-enzymatic reduction; TiO/r-GQDs nanocomposite; Upconversion","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-04","","","BT/Biocatalysis","","",""
"uuid:9da35f86-c7b1-4ac1-8efd-adcd4c8b730a","http://resolver.tudelft.nl/uuid:9da35f86-c7b1-4ac1-8efd-adcd4c8b730a","Miniaturized therapeutic systems for ultrasound-modulated drug delivery to the central and peripheral nervous system","Zhu, P. (TU Delft ChemE/Product and Process Engineering; Nanjing University of Aeronautics and Astronautics; The Hong Kong Polytechnic University); Simón Grau, I. (TU Delft ChemE/Product and Process Engineering); Kokalari, I. (TU Delft ChemE/Product and Process Engineering); Kohane, Daniel S. (Harvard Medical School); Rwei, A.Y. (TU Delft ChemE/Product and Process Engineering)","","2024","Ultrasound is a promising technology to address challenges in drug delivery, including limited drug penetration across physiological barriers and ineffective targeting. Here we provide an overview of the significant advances made in recent years in overcoming technical and pharmacological barriers using ultrasound-assisted drug delivery to the central and peripheral nervous system. We commence by exploring the fundamental principles of ultrasound physics and its interaction with tissue. The mechanisms of ultrasonic-enhanced drug delivery are examined, as well as the relevant tissue barriers. We highlight drug transport through such tissue barriers utilizing insonation alone, in combination with ultrasound contrast agents (e.g., microbubbles), and through innovative particulate drug delivery systems. Furthermore, we review advances in systems and devices for providing therapeutic ultrasound, as their practicality and accessibility are crucial for clinical application.","Cavitation; Implantable device; Microbubble; Sonochemistry; Sonosensitizer; Ultrasound transducer; Wearable device","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-03","","","ChemE/Product and Process Engineering","","",""
"uuid:95828fcd-3ab5-4d1b-85b5-a5e209d9ca4f","http://resolver.tudelft.nl/uuid:95828fcd-3ab5-4d1b-85b5-a5e209d9ca4f","Failure probability estimation of natural gas pipelines due to hydrogen embrittlement using an improved fuzzy fault tree approach","Qin, Guojin (Southwest Petroleum University; Shanghai Jiao Tong University); Li, Ruiling (Southwest Petroleum University); Yang, M. (TU Delft Safety and Security Science; Universiti Teknologi Malaysia; University of Tasmania); Wang, Bohong (Zhejiang Ocean University); Ni, Pingan (Xi'an University of Architecture and Technology); Wang, Yihuan (Southwest Petroleum University; Shanghai Jiao Tong University)","","2024","The estimation of failure probability is challenging in hydrogen embrittlement in steel pipelines due to the complexity of the synergistic effect of multiple factors. The present study proposed a hybrid methodology to estimate the failure probability of steel pipelines due to hydrogen embrittlement. The methodology integrates the fault tree analysis with a fuzzy comprehensive evaluation. Fault tree analysis captures the logical relationships between influencing indicators to develop a new assessment model of hydrogen embrittlement in steel pipelines. An improved fuzzy fault tree analysis method was proposed to process aleatoric and epistemic uncertainties to estimate the probability of each basic event due to the difficulty in obtaining the actual probabilities. The failure probability of blended hydrogen natural gas pipelines was estimated by considering the correlation of events. A case study demonstrated the applicability of the proposed method. Maintenance measures can be implemented according to the evaluation results to ensure pipeline safety.","Blended hydrogen natural gas pipelines; Failure probability estimation; Fuzzy fault tree analysis; Hydrogen blistering; Hydrogen embrittlement; Hydrogen-induced cracking","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-05","","","Safety and Security Science","","",""
"uuid:706447a5-6e75-4751-8bcc-4ab593c53bfd","http://resolver.tudelft.nl/uuid:706447a5-6e75-4751-8bcc-4ab593c53bfd","Elucidating the role of water in collagen self-assembly by isotopically modulating collagen hydration","Giubertoni, Giulia (Universiteit van Amsterdam); Feng, Liru (Universiteit van Amsterdam); Klein, Kevin (Institute of Science and Technology Austria; University College London (UCL)); Giannetti, Guido (Universiteit van Amsterdam); Rutten, Luco (Radboud University Medical Center); van der Net, J.J.P. (TU Delft BN/Gijsje Koenderink Lab; Kavli institute of nanoscience Delft); Castro Linares, G. (TU Delft BN/Gijsje Koenderink Lab; Kavli institute of nanoscience Delft); Koenderink, G.H. (TU Delft BN/Gijsje Koenderink Lab; Kavli institute of nanoscience Delft); Woutersen, Sander (Universiteit van Amsterdam)","","2024","Water is known to play an important role in collagen self-assembly, but it is still largely unclear how water-collagen interactions influence the assembly process and determine the fibril network properties. Here, we use the H[Formula: see text]O/D[Formula: see text]O isotope effect on the hydrogen-bond strength in water to investigate the role of hydration in collagen self-assembly. We dissolve collagen in H[Formula: see text]O and D[Formula: see text]O and compare the growth kinetics and the structure of the collagen assemblies formed in these water isotopomers. Surprisingly, collagen assembly occurs ten times faster in D[Formula: see text]O than in H[Formula: see text]O, and collagen in D[Formula: see text]O self-assembles into much thinner fibrils, that form a more inhomogeneous and softer network, with a fourfold reduction in elastic modulus when compared to H[Formula: see text]O. Combining spectroscopic measurements with atomistic simulations, we show that collagen in D[Formula: see text]O is less hydrated than in H[Formula: see text]O. This partial dehydration lowers the enthalpic penalty for water removal and reorganization at the collagen-water interface, increasing the self-assembly rate and the number of nucleation centers, leading to thinner fibrils and a softer network. Coarse-grained simulations show that the acceleration in the initial nucleation rate can be reproduced by the enhancement of electrostatic interactions. These results show that water acts as a mediator between collagen monomers, by modulating their interactions so as to optimize the assembly process and, thus, the final network properties. We believe that isotopically modulating the hydration of proteins can be a valuable method to investigate the role of water in protein structural dynamics and protein self-assembly.","collagen tissue; hydration; mechanics; molecular structure","en","journal article","","","","","","","","","","","BN/Gijsje Koenderink Lab","","",""
"uuid:f9b11417-4373-477e-8f97-baf65c9db7a1","http://resolver.tudelft.nl/uuid:f9b11417-4373-477e-8f97-baf65c9db7a1","Green photocatalytic mixed matrix membranes for simultaneous arsenic photo-oxidation and water recovery via membrane distillation","Santoro, Sergio (University of Calabria); Occhiuzzi, Jessica (University of L'Aquila); Aquino, Marco (University of Calabria); Politano, Antonio (University of L'Aquila); Straface, Salvatore (University of Calabria); D'Andrea, Giuseppe (University of Calabria); Carrillo, Cristobal (Universidad de Zaragoza); Mallada, Reyes (Universidad de Zaragoza); Garcia, Andreina (Universidad de Chile); Estay, Humberto (Universidad de Chile); Xevgenos, Dimitris (TU Delft Energie and Industrie); Argurio, Pietro (University of Calabria); Curcio, Efrem (University of Calabria)","","2024","This work proposes an innovative integration of Membrane Distillation (MD) and photo-oxidation for a continuous recovery of water from arsenic (As) contaminated solutions coupled with the oxidation of arsenite (As(III)) into arsenate (As(V)). Polyvinylidene fluoride (PVDF) mixed matrix membranes (MMMs) containing titanium dioxide nanoparticles (TiO2 NPs) as photocatalyst were developed. A systematic study elucidated the effect of TiO2 NPs on membranes’ morphology prepared via non-solvent-induced phase separation (NIPS) using triethyl phosphate (TEP) as a green solvent for PVDF solubilization. Vacuum membrane distillation (VMD) tests carried out by irradiating the MMMs with ultraviolet (UV) radiation demonstrated the possibility of recovering up to 80 % of the water from As-contaminated synthetic and real multi-ions aqueous solutions from Sila Massif (Italy). The distillate was recovered at a rate of 6.9–7.2 kg·m−2·h−1 (feed inlet temperature of 60 °C), while the presence of 7 wt% of TiO2 in PVDF membranes enabled the photo-oxidation of 95 % of the As(III) to As(V) at a first order kinetic constant of 0.0106 min−1. After 5 cycles of As-remediation experiments, post-hoc mechanical testing on the membrane suggested the emergence of polymer embrittlement induced by UV radiation (total irradiation time of 7.5 h), highlighting the urgent need for developing photocatalytic membranes with long-term stability. Overall, this study elucidates at laboratory scale the performance of a coupled and continuous Membrane Distillation (MD) and photo-oxidation system for arsenic (As) remediation, employing microporous hydrophobic green membranes doped with a photocatalyst.","Arsenic; Green Solvent; Membrane Distillation; Photo-oxidation; Photocatalytic Membranes","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:c2d86979-2727-438e-9604-1cbdb42bc621","http://resolver.tudelft.nl/uuid:c2d86979-2727-438e-9604-1cbdb42bc621","Caste, mistrust and municipal inaction: The interwoven barriers for the integration of waste pickers in India","Juárez Pastor, Lidia (Universiteit Leiden); Subramanian, Vrishali (Universiteit Leiden); Cucurachi, S. (Universiteit Leiden); Ghorbani, Amineh (TU Delft System Engineering)","","2024","Solid waste management in low- and middle-income countries like India faces significant challenges due to the increasing waste generation that surpasses the current capacity. Therefore, the informal waste sector (IWS) is more vital than ever in handling consumer waste alongside municipal solid waste management (SWM) systems. However, the integration of the IWS into formal waste management systems remains unresolved due to adverse social and economic conditions. This study focuses on identifying the root causes that hinder the integration of the IWS in India's waste management system, using the city of Chennai as a case study. Adopting an institutional perspective, we analyse the institutional landscape of the waste management system, considering both formal rules (in policy documents) and informal rules (i.e., social norms and routines). The institutional network analysis reveals a significant misalignment in perceptions among governance levels concerning the integration of the IWS. The study shows a considerable gap between rules-in-form and rules-in-use, leading to 1) Preclusion of waste pickers in collecting door-to-door source-segregated waste (i.e., recyclables). 2) Unfair pricing in transactions with small aggregators. 3) Lack of ID cards for waste pickers. These barriers are ultimately rooted in caste discrimination, misalignment between governance levels, and the exclusion of waste pickers in the policymaking process. In conclusion, understanding and rectifying the institutional gaps and discriminatory practices are essential steps towards effectively integrating the IWS in India's waste management system, promoting a more inclusive and sustainable approach to waste management.","Informal waste sector; Institutional grammar; Institutional network analysis; Solid waste management; Waste pickers","en","journal article","","","","","","","","","","","System Engineering","","",""
"uuid:c7f2ab48-896c-4d09-adc3-afcc12b64c1b","http://resolver.tudelft.nl/uuid:c7f2ab48-896c-4d09-adc3-afcc12b64c1b","What is conceptual disruption?","Marchiori, S. (TU Delft Ethics & Philosophy of Technology); Scharp, Kevin (University of Illinois at Urbana-Champaign; University of Twente)","","2024","Recent work on philosophy of technology emphasises the ways in which technology can disrupt our concepts and conceptual schemes. We analyse and challenge existing accounts of conceptual disruption, criticising views according to which conceptual disruption can be understood in terms of uncertainty for conceptual application, as well as views assuming all instances of conceptual disruption occur at the same level. We proceed to provide our own account of conceptual disruption as an interruption in the normal functioning of concepts and conceptual schemes. Moreover, we offer a multilevel taxonomy thereof, where we distinguish between instances of conceptual disruptions occurring at different levels (conceptual scheme, conceptual clusters, and individual concepts), taking on different forms (conceptual gaps and conceptual conflicts), and leading to different degrees of severity (extending from mild to severe). We also provide detailed accounts through historical examples of how conceptual gaps and conceptual conflicts can occur at different times in the very same process of conceptual disruption. Finally, we make the case that different kinds of conceptual engineering can provide meaningful ways to assess and overcome distinct types of conceptual disruption.","Conceptual disruption; Conceptual engineering; Socially disruptive technologies; Conceptual gap; Conceptual conflict; Conceptual overlap; Conceptual change; Philosophy of technology","en","journal article","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:3e45705e-6af5-42ea-8beb-adbce382ea6e","http://resolver.tudelft.nl/uuid:3e45705e-6af5-42ea-8beb-adbce382ea6e","Design Thinking Tools to Catalyse Sustainable Circular Innovation","Bocken, Nancy (Universiteit Maastricht); Baldassarre, Brian (Universiteit Maastricht; Roskilde University); Keskin, Duygu (Eindhoven University of Technology); Diehl, J.C. (TU Delft Design for Sustainability)","Lehtimäki, Hanna (editor); Aarikka-Stenroos, Leena (editor); Jokinen, Ari (editor); Jokinen, Pekka (editor)","2024","Design thinking is an innovation approach for organisations aiming to solve complex and open-ended problems, including those arising in the transition from a linear to a circular economic system. Although the importance has been recognised in business and academia, to date, insight is lacking on how design thinking can be applied within circular innovation specifically. We investigate the following research question: How can design thinking tools catalyse sustainable circular innovation? Based on the literature, we first create a framework that characterises design thinking principles, criteria and phases that could support circular innovation. The design thinking phases are ideate and design, implement and test, and evaluate and improve. The criteria include desirability, feasibility, viability and sustainability, and circularity. Finally, we identify the following principles that make design thinking suitable to tackle complex circular innovation challenges: human-centred, future-oriented, holistic, co-creative, and experimental. Consequently, against this framework, we map 11 tools that are suitable to catalyse circular innovation theory into practice through design thinking. Finally, we reflect on the future of research and practice around this subject.","","en","book chapter","Routledge - Taylor & Francis Group","","","","","The publication was funded by the University of Eastern Finland, Tampere University, LUT University, and the University of Turku.","","","","","Design for Sustainability","","",""
"uuid:5cc07754-dab1-4dd4-8446-d489ebd08c4c","http://resolver.tudelft.nl/uuid:5cc07754-dab1-4dd4-8446-d489ebd08c4c","The effective velocity model: An improved approach to velocity sampling in actuator line models","Muscari, C. (TU Delft Team Jan-Willem van Wingerden; Politecnico di Milano); Schito, Paolo (Politecnico di Milano); Viré, A.C. (TU Delft Wind Energy); Zasso, Alberto (Politecnico di Milano); van Wingerden, J.W. (TU Delft Team Jan-Willem van Wingerden)","","2024","Actuator line modeling of wind turbines requires the definition of a free-stream velocity in a computational mesh and a regularization kernel to project the computed body forces onto the domain. Both choices strongly influence the results. In this work, a novel velocity sampling method—the so-called effective velocity model (EVM)—is implemented in the CFD software SOWFA, validated, and compared to pre-existing approaches. Results show superior method robustness with respect to the regularization kernel width ((Formula presented.)) choice while preserving acceptable accuracy. In particular, the power predicted by the EVM is nearly independent of the (Formula presented.) value.","actuator line model; CFD; LES; regularization kernel; velocity sampling; wind turbine modeling","en","journal article","","","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:0b452612-dd39-4850-affe-00f25bec66cd","http://resolver.tudelft.nl/uuid:0b452612-dd39-4850-affe-00f25bec66cd","Naturally effective inhibition of microbial corrosion on carbon steel by beneficial biofilm in the South China Sea","Gao, Yu (Northeastern University China); Zhang, Jingru (Northeastern University China); Wang, Donglei (Northeastern University China); Fan, Jiaxin (Northeastern University China); Mol, J.M.C. (TU Delft Team Arjan Mol); Wang, Fuhui (Northeastern University China); Zhang, Danni (Northeastern University China); Xu, Dake (Northeastern University China)","","2024","Microbially influenced corrosion (MIC) of metals exerts a negative effect on the marine environment and causes a great loss of marine facilities. Corrosion prevention in an eco-friendly and sustainable way is a difficult problem to address, especially in the marine environment. In this work, Nocardiopsis dassonville, a corrosive bacteria isolated from the South China Sea was studied by using carbon steel. The results indicate that N. dassonville caused a corrosion loss of 7.68 mg cm−2 and a corrosion pit of 13.0 μm on the carbon steel surface, but the corrosion is inhibited in the presence of Vibrio sp. EF187016 in the medium. Vibrio sp. EF187016 preferentially occupied the carbon steel surface, forming a protective biofilm that hindered the attachment of N. dassonville. In addition, extracellular polymeric substances extracted from Vibrio sp. EF187016 was added to N. dassonvillei inoculated medium and showed a significant inhibition of MIC on carbon steel.","Biofilms; Carbon steel; Corrosion inhibition; Extracellular polymeric substances; Marine environment","en","journal article","","","","","","","","","","","Team Arjan Mol","","",""
"uuid:6b6f382c-8d3d-4147-b961-bfbb752ab29c","http://resolver.tudelft.nl/uuid:6b6f382c-8d3d-4147-b961-bfbb752ab29c","Influence of mixing time on a reversal tolerant anode measured ex situ for a PEMFC","Homan, S.J.T. (TU Delft ChemE/Catalysis Engineering; cellcentric GmbH & Co. KG); Aylar, K. (cellcentric GmbH & Co. KG); Jurjevic, A. (cellcentric GmbH & Co. KG); Scolari, M. (cellcentric GmbH & Co. KG); Urakawa, A. (TU Delft ChemE/Catalysis Engineering); Taheri, P. (TU Delft Team Peyman Taheri)","","2024","When no hydrogen can reach the Pt catalyst in the anode for the hydrogen oxidation reaction (HOR) of an operating proton exchange membrane fuel cell (PEMFC), the anode potential increases and causes the cell potential to be reversed compared to normal operation conditions. During this reversal, the oxygen evolution reaction (OER) and carbon oxidation reaction (COR) will occur at the anode, where the COR has devastating consequences for the electrode. Introducing an OER catalyst limits the COR to occur, which makes a reversal tolerant anode (RTA). In this research, RTAs are differentiated by applying different ball milling times during catalyst layer processing, forming big and small OER (IrOx/TiOx) and HOR (Pt/C) catalyst particles. The two different particle sizes were electrochemically tested using a rotating disc electrode (RDE). Both catalyst sizes show a decrease in OER activity (mA cm−2) accompanied by loss of the ionomer in a self-developed accelerated stress test (AST). The small particle RTAs show higher OER activity as a result of increased surface area. However, during a chronopotentiometry measurement, which mimics a fuel cell reversal, the small particle coatings show a worse reversal tolerance. This phenomenon can be attributed to the increased difficulty in removing oxygen bubbles.","Catalyst layer processing; OER catalyst; PEMFC; Reversal tolerant anode (RTA); Rotating disc electrode (RDE)","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:3017d17f-e7d1-4d5e-9bd9-c5ca7a3fd234","http://resolver.tudelft.nl/uuid:3017d17f-e7d1-4d5e-9bd9-c5ca7a3fd234","Electronic Properties of Ultrathin InGaN/GaN Heterostructures under the Influences of Laser and Electric Fields: Investigation of the Harmonic and Inharmonic Potentials","En-nadir, Redouane (University of Sidi Mohamed Ben Abdullah); El Ghazi, Haddou (University of Sidi Mohamed Ben Abdullah; Hassan II University of Casablanca); Basyooni, Mohamed A. (TU Delft Dynamics of Micro and Nano Systems; Selçuk University); Tihtih, Mohammed (University of Miskolc); Belaid, Walid; Abboudi, Hassan (University of Sidi Mohamed Ben Abdullah); Maouhoubi, Ibrahim (University of Sidi Mohamed Ben Abdullah); Rabah, Mohamed (University of Sidi Mohamed Ben Abdullah; Hassan II University of Casablanca); Zorkani, Izeddine (University of Sidi Mohamed Ben Abdullah)","","2024","Defects and impurities within semiconductor materials pose significant challenges. This investigation scrutinizes the response of a single dopant donor impurity located in nanostructured semiconductors, specifically quantum wells subjected to both harmonic and inharmonic confinement potentials. The primary focus of this inquiry centers on the analysis of binding energy, electron probability distribution, and diamagnetic susceptibility in connection with both the ground (1s) and excited (2p) electron states. Utilizing advanced computational techniques, specifically the Finite Elements Method (FEM) implemented through Python code, this study unveils a marked alteration in the interaction between electrons and impurities when exposed to external fields. Significantly, the characteristics of the confinement potential exert a substantial influence on the explored physical parameters. This research significantly advances our understanding of the interaction between impurities and intense fields, offering valuable insights into solid-state phenomena within low-dimensional systems. Consequently, it contributes to the design and fabrication of next-generation applications in the field of quantum well systems, encompassing areas such as lighting, detection, information processing, sensing, and energy conversion.","Binding-energy; Diamagnetic-susceptibility; Harmonicity; Intense external fields; Nanostructures; Probability-distribution","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-19","","","Dynamics of Micro and Nano Systems","","",""
"uuid:93b6b653-65d5-42d8-83e2-bd58dd77ae67","http://resolver.tudelft.nl/uuid:93b6b653-65d5-42d8-83e2-bd58dd77ae67","Crashworthiness in preliminary design: Mean crushing force prediction for closed-section thin-walled metallic structures","Anand, S. (TU Delft Group Giovani Pereira Castro); Alderliesten, R.C. (TU Delft Group Alderliesten); Castro, Saullo G.P. (TU Delft Group Giovani Pereira Castro)","","2024","To design crash structures for disruptive aircraft designs, it is required to have fast and accurate methods that can predict crashworthiness of aircraft structures early in the design phase. Axial crushing is one of the key energy absorbing mechanisms during a crash event. In this study, various analytical models proposed for calculation of mean crushing force for thin-walled tubular structures are compared with a database of numerical and experimental values to ascertain their accuracy. Improvements to some of the models have also been proposed. Finally a generalized model based on the studied and improved analytical models for prediction of mean crushing force for closed section thin-walled tubular structures is introduced. The generalized model demonstrates high accuracy when compared against experimental/numerical dataset as evidenced by a high coefficient of determination (R2) value of 0.97 and can therefore be used to estimate the mean crushing force for closed-section thin-walled metallic tubular structures with various cross-sectional shapes and crushing modes early in the design phase.","Analytical models; Axial crushing; Crashworthiness; Metallic tubular structures; Preliminary design; Thin walled structures","en","journal article","","","","","","","","","","","Group Giovani Pereira Castro","","",""
"uuid:2b81c1fa-e121-419b-94be-4d0c24767589","http://resolver.tudelft.nl/uuid:2b81c1fa-e121-419b-94be-4d0c24767589","Uncovering the spread of drug-resistant bacteria through next-generation sequencing based surveillance: transmission of extended-spectrum β-lactamase-producing Enterobacterales by a contaminated duodenoscope","Cimen, Cansu (University Medical Center Groningen; University of Oldenburg); Bathoorn, Erik (University Medical Center Groningen); Loeve, A.J. (TU Delft Medical Instruments & Bio-Inspired Technology); Fliss, Monika (University Medical Center Groningen); Berends, Matthijs S. (University Medical Center Groningen); Nagengast, Wouter B. (University Medical Center Groningen); Hamprecht, Axel (University of Oldenburg); Voss, Andreas (University Medical Center Groningen); Lokate, Mariëtte (University Medical Center Groningen)","","2024","Contamination of duodenoscopes is a significant concern due to the transmission of multidrug-resistant organisms (MDROs) among patients who undergo endoscopic retrograde cholangiopancreatography (ERCP), resulting in outbreaks worldwide. In July 2020, it was determined that three different patients, all had undergone ERCP with the same duodenoscope, were infected. Two patients were infected with blaCTX-M-15 encoding Citrobacter freundii, one experiencing a bloodstream infection and the other a urinary tract infection, while another patient had a bloodstream infection caused by blaSHV-12 encoding Klebsiella pneumoniae. Molecular characterization of isolates was available as every ESBL-producing isolate undergoes Next-Generation Sequencing (NGS) for comprehensive genomic analysis in our center. After withdrawing the suspected duodenoscope, we initiated comprehensive epidemiological research, encompassing case investigations, along with a thorough duodenoscope investigation. Screening of patients who had undergone ERCP with the implicated duodenoscope, as well as a selection of hospitalized patients who had ERCP with a different duodenoscope during the outbreak period, led to the discovery of three additional cases of colonization in addition to the three infections initially detected. No microorganisms were detected in eight routine culture samples retrieved from the suspected duodenoscope. Only after destructive dismantling of the duodenoscope, the forceps elevator was found to be positive for blaSHV-12 encoding K. pneumoniae which was identical to the isolates detected in three patients. This study highlights the importance of using NGS to monitor the transmission of MDROs and demonstrates that standard cultures may fail to detect contaminated medical equipment such as duodenoscopes.","Citrobacter freundii; Contamination; CTXM-15; Duodenoscope; Endoscopic retrograde cholangiopancreatography (ERCP); Extended-spectrum β-lactamase (ESBL); Klebsiella pneumoniae; Multi locus sequence typing (MLST); Next-generation sequencing (NGS); Nosocomial transmission; SHV-12","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:f7d604b6-cb03-43be-8091-743dd2ccbe3f","http://resolver.tudelft.nl/uuid:f7d604b6-cb03-43be-8091-743dd2ccbe3f","Thermodynamic analysis and heat exchanger calculations of transcritical high-temperature heat pumps","Zhao, A. (TU Delft Energy Technology); Pecnik, Rene (TU Delft Energy Technology); Peeters, J.W.R. (TU Delft Energy Technology)","","2024","Heating in industrial processes is responsible for approximately 13% of greenhouse gas emissions in Europe. Switching from fossil-fuel based boilers to heat pumps can help mitigate the effect of global warming. The present work proposes novel high-temperature transcritical heat pump cycles targeted at heating air with a mass flow rate of 10 kg/s up to 200 °C for spray drying processes. Four low-GWP refrigerants, R1233zd(E), R1336mzz(Z), n-Butane, and Ammonia are considered as the candidate working fluids. The pressure ratio of the compressor is optimized to achieve a maximum coefficient of performance (COP) for the four working fluids. A shell & tube heat exchanger is considered as the gas cooler. Using a generalized version of the ϵ-NTU method, the gas cooler is sized and a second law analysis is conducted. Striking a balance between the first- and second-law performance and size of the gas cooler, the R1233zd(E) transcritical heat pump cycle with a COP of 3.6 is judged to be the most promising option.","Heat pump; Low-GWP refrigerants; Second law analysis; Transcritical","en","journal article","","","","","","","","","","","Energy Technology","","",""
"uuid:77766c62-fd3a-4cdb-845e-269194bf19ec","http://resolver.tudelft.nl/uuid:77766c62-fd3a-4cdb-845e-269194bf19ec","Characterization, pre-treatment, and potential applications of fine MSWI bottom ash as a supplementary cementitious material","Sun, Y. (TU Delft Civil Engineering & Geosciences; Universiteit Gent); Chen, B. (TU Delft Materials and Environment); Zhang, Shizhe (TU Delft Materials and Environment); Blom, C.B.M. (TU Delft Concrete Structures; Gemeente Rotterdam); Lukovic, M. (TU Delft Concrete Structures); Ye, G. (TU Delft Materials and Environment; Universiteit Gent)","","2024","With the development of waste recovery techniques, previous research has revealed that coarse fractions of municipal solid waste incineration (MSWI) bottom ash (BA) after proper treatment could be applied in the construction sector, while the fines are seldom recovered in practice and normally landfilled. This study explores the potential application of fine MSWI BA (0–2 mm) as a supplementary cementitious material (SCM) in Portland cement (PC) mixtures. Mechanical and chemical pre-treatment approaches have been designed with various conditions to optimize the treating process. The chemical and mineralogical compositions, as well as the metallic Al content in BA were characterized before and after the pre-treatment. It was found that both methods are effective in removing the metallic Al content in BA, Moreover, BA derived from mechanical treatment exhibited more contribution to the hydration reaction in PC mixtures, as revealed by the amount of reaction products and mineral phases formed in hardened trial mixtures. BA obtained was further partially blended in PC mortars to evaluate the performance as compared to SCMs and inert fillers. It was found that treated BA resulted in a slight retarding effect on the reaction kinetics. Treated BA behaved better than the coal fly ash to contribute to the strength development, while the inclusion of BA did not lead to significant influences on the workability.","characterization; metallic Al; MSWI BA; pre-treatment; supplementary cementitious material","en","journal article","","","","","","","","","Civil Engineering & Geosciences","","Materials and Environment","","",""
"uuid:52cd2325-280b-4c22-9398-24588bccbbb3","http://resolver.tudelft.nl/uuid:52cd2325-280b-4c22-9398-24588bccbbb3","Employee Perspectives on Risk Management in a Construction Company","Ökmen, Ö. (TU Delft Integral Design & Management); Leijten, M. (TU Delft Organisation & Governance); Strattona, Theodora (Student TU Delft); Bosch-Rekveldt, M.G.C. (TU Delft Integral Design & Management); Bakker, H.L.M. (TU Delft Integral Design & Management)","","2024","In addition to the tools and techniques available, project risk management also depends on the attitudes of people in an organisation, how the available tools are used, and how the procedures are followed. Therefore, efforts to improve the project risk management capacity of organisations may fail if the diversity of people (characters, traits etc.) involved is neglected. Based on this argument, the aim of this study is to demonstrate that companies can improve project risk management using the perspectives of their key experts. In this context, an approach was proposed based on Q-Methodology and a case study has been conducted in a construction company in the Netherlands. The quantitative output obtained through Q-Methodology application was evaluated in conjunction with the qualitative data gathered from interviews conducted with the managers of different units within the company. As a result of this evaluation, three common perspectives were identified among the respondents under the names of ‘Experience and Belief’, ‘Procedures and Management’ and ‘Culture and Communication’, respectively. Then, a number of recommendations were made to the company. First, customized management approaches that integrate and balance the identified perspectives should be adopted. Second, a mature organisational risk management culture should be promoted. Project charters that specifically target risk management culture in projects can be used for this purpose. Third, risk management should be integrated into other activities, making it a normal part of employees’ daily work. Finally, but not exclusively, the employees should be instructed on the use of risk registers and guidance should be put in place on how often they are expected to update the risk registers. This study demonstrates the benefit of considering employee diversity and leveraging perspectives in unlocking the potential of construction companies in terms of project risk management.","construction companies; critical success factors; Netherlands; Project risk management; Q-Methodology","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:c6ce1b5f-3341-4a09-af78-4dc2191b3d40","http://resolver.tudelft.nl/uuid:c6ce1b5f-3341-4a09-af78-4dc2191b3d40","Recovery of microbial biomass and purification performance after scraping of full-scale slow sand filters","Trikannad, S.A. (TU Delft Sanitary Engineering); Attiani, Valentina (Wageningen University & Research); van der Wielen, Paul W.J.J. (KWR Water Research Institute; Wageningen University & Research); Smidt, Hauke (Wageningen University & Research); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet); van Halem, D. (TU Delft Sanitary Engineering)","","2024","Slow sand filters (SSFs) are widely used in drinking water production to improve microbial safety and biological stability of water. Full-scale SSFs are maintained by scraping the biomass-rich top layers of sand. The period of downtime required for filter recovery after scraping is a major challenge due to limited knowledge of the re-stabilisation of purification processes. This study examined the recovery of microbial biomass, and removal of dissolved organic carbon (DOC) and ammonium (NH4+) in water phase and/or on sand along the depth of a scraped full-scale SSF. Scraping reduced microbial biomass on sand in the top layers, while the main prokaryotic taxa remained unaltered. Cellular ATP (cATP) and intact cell counts (ICC) in water sampled from the top layers increased, indicating a temporary disruption in functionality for 37 days. However, stable concentrations of cATP and ICC and similar microbial community composition in the effluent after scraping revealed that deeper layer biofilms offset any scraping effect. Consistent DOC and NH4+ removal after scraping showed that deeper layers effectively performed the role of the top layer. These findings highlight the resilience and robustness of microbial communities in mature full-scale SSFs and their contribution to water treatment efficiency after disturbances caused by scraping.","Slow sand filters; Schmutzdecke; Scraping; Ripening period; Dissolved organic carbon; Ammonium","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:6123c331-fc12-4762-979c-6e37763836d1","http://resolver.tudelft.nl/uuid:6123c331-fc12-4762-979c-6e37763836d1","Adapting a systems perspective for sectoral coordination: Approaching flood resilience in Houston and Accra","Ersoy, A. (TU Delft Urban Development Management); Brand, A.D. (TU Delft Research Support & Innovation); van Bueren, Ellen (TU Delft Management in the Built Environment)","","2024","Increasing resilience to flooding is a complex process that requires horizontal and vertical coordination between institutions in policy making and implementation. This paper explores the effect of institutional coordination on managing flood risk in two cities plagued by flooding. Our results show that efforts on building urban flood resilience can be undermined by lack of proper coordination between urban development, water management and land use planning. We find that this complexity is magnified by the emergence of the concept of resilience as an urban development goal that is increasingly pursued by various authorities, but that is inherently contested in practice.","flood resilience; systems approach; coordination; Houston; Accra","en","journal article","","","","","","","","","","Management in the Built Environment","Urban Development Management","","",""
"uuid:6095bdda-c2c5-490a-86ef-4731112d6d57","http://resolver.tudelft.nl/uuid:6095bdda-c2c5-490a-86ef-4731112d6d57","Energietransities: Verenigen van tegengestelde eisen met het paradoxperspectief","Greco, A. (TU Delft Real Estate Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Wanneer een gebouw leeg komt te staan, worden vastgoedontwikkelaars, investeerders en eigenaren geconfronteerd met uiteenlopende eisen: in sommige gevallen is er grote behoefte aan snel financieel rendement, in andere gevallen vormt het behoud van historische waarden een uitdaging die maatregelen op het gebied van energie-efficiëntie bemoeilijkt. Dit heeft op de lange termijn negatieve gevolgen voor de Nederlandse vastgoedmarkt: het tempo van de energierenovatie ligt te laag en moet dringend worden verhoogd.
Dit hoofdstuk introduceert een paradoxaal perspectief op de uitdagingen en tegengestelde belangen die de energietransitie blijven belemmeren. Een paradoxale benadering erkent dat deze spanningen onderling samenhangen en aanhoudend zijn. Een compromis is niet wenselijk, omdat het negeren van tegengestelde belangen tot negatieve onbedoelde gevolgen leidt.
Dit hoofdstuk geeft ten eerste een overzicht van enkele van de belangrijkste uitdagingen die relevant zijn voor het bereiken van energie-efficiëntie bij de transformatie van bestaande gebouwen. Vervolgens wordt de paradoxtheorie belicht en de daaruit voorkomende benaderingen. Een paradoxperspectief is relevant voor zowel onderzoekers en managers die moeten omgaan met concurrerende eisen, als voor ontwerpers die paradoxen kunnen gebruiken als drijvende kracht om creatieve oplossingen te vinden.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Real Estate Management","","",""
"uuid:ec338c5f-3098-4cd5-a5e6-a953cbac5ef9","http://resolver.tudelft.nl/uuid:ec338c5f-3098-4cd5-a5e6-a953cbac5ef9","Integration of Business and User-Centered Corporate Real Estate and Facilities Management","van der Voordt, Theo (TU Delft Real Estate Management)","Rondeau, Edmond P. (editor); Hellerforth, Michaela (editor)","2024","A red thread in my academic carrier of over 40 years is the development and sharing of knowledge about the experience and use of the built environment, including offices, health care facilities, childcare facilities, learning environments, housing, and public spaces. The latter is currently part of urban FM. My main drive to do this for such a long time is the willingness to contribute to an environment that enables people to conduct their activities in a satisfactory, comfortable, efficient and effective way, and that fits with the preferences, needs and values of organizations, customers, end users and society as a whole. In other words: to contribute to user-centered and value-based briefing, design, management, evaluation and further improvement of buildings, facilities and services.","","en","book chapter","Wiley","","","","","","","","","","Real Estate Management","","",""
"uuid:d98228e6-0e53-4aa6-8d9f-db3fbde896af","http://resolver.tudelft.nl/uuid:d98228e6-0e53-4aa6-8d9f-db3fbde896af","Bedrijvigheid en wonen: Van Central Business naar Central (re)manufacturing district?","Van den Berghe, K.B.J. (TU Delft Urban Development Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Bedrijvigheid en wonen in de stad zijn met elkaar verbonden. Doel van dit hoofdstuk is de causaliteit van waarom we woningen in de stad nodig hebben kritisch in context en tijd te plaatsen. Causaliteit beschrijft de relatie tussen oorzaak en gevolg. Wonen in de stad wordt hier als een gevolg gezien van een bepaalde oorzaak, maar deze oorzaak verandert door de tijd en geografische ontwikkeling heen. De propositie van dit hoofdstuk is dat we aan het begin staan van een nieuw tijdperk, waarin de oorzaak waarom we woningen in de stad nodig hebben, verandert. Vooral voor Nederlandse steden zou dit weleens een belangrijke verandering kunnen zijn. De centrale boodschap van dit boekhoofdstuk is dat het daarom nodig is om deze mogelijke verandering ten eerste niet (impliciet) te negeren, en ten tweede de mogelijke gevolgen goed te begrijpen wanneer we in de praktijk in steden gebouwen en gebieden transformeren naar woningen. Dit leidt tot de centrale onderzoeksvraag van dit essay: Wat is de rol van stedelijke transformatie vandaag voor de ontwikkeling van steden in de toekomst?
Om deze vraag te beantwoorden, zal eerst een korte beschrijving gegeven worden van hoe de stad gezien kan worden als een causaal gevolg van een maatschappelijke noodzaak aan toegevoegde waarde. Dit verklaart waarom bepaalde steden om bepaalde redenen ontstaan zijn, verdwenen zijn, of zich aangepast hebben. Vervolgens wordt de industriële stad uitgelegd als een belangrijk kantelpunt voor de rol van stad in de moderne maatschappij. Na de beschrijving van de post-industriële stad, wordt uitgelegd dat de hoogtijdagen van dit tijdperk hoogstwaarschijnlijk voorbij zijn, en dat dus de oorzaak van waarom we wonen in de stad nodig hebben weleens zou kunnen veranderen. Het hoofdstuk eindigt met een conclusie waarin een antwoord wordt geformuleerd op de onderzoeksvraag.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Urban Development Management","","",""
"uuid:a57b67f9-9dee-413b-a358-20f8393529eb","http://resolver.tudelft.nl/uuid:a57b67f9-9dee-413b-a358-20f8393529eb","Projecten","Remøy, H.T. (TU Delft Real Estate Management); van Venrooij, R.G.A.M. (TU Delft Support Management in the Built Environment); Snoek, T.E. (TU Delft Support Management in the Built Environment)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Om het woningtekort op te lossen moeten er jaarlijks zo’n 90.000 nieuwbouwwoningen aan het woningbestand worden toegevoegd. Transformatie van leegstaande gebouwen en herbestemming naar woningen draagt bij aan de oplossing hiervoor. De maatschappij stelt hogere eisen aan duurzaamheid dan voorheen, en stelt randvoorwaarden zoals lager energieverbruik, beter omgaan met bouwmaterialen en minder afval genereren. Transformatie voldoet aan deze duurzaamheidseisen. In de transitie naar een circulaire economie is er meer aandacht voor hergebruik van bouwcomponenten en materialen. Dit is iets wat steeds vaker gebeurt, maar wat nog niet algemeen is. Voor de financiële crisis van 2008 kwam transformatie minder vaak voor. Leegstaande gebouwen werden vaak gesloopt in plaats van getransformeerd. Tegenwoordig zijn volledige nieuwbouwprojecten eerder uitzondering dan regel, en de verschuiving naar herbestemming weerspiegelt dan ook de veranderde maatschappelijke eisen.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Real Estate Management","","",""
"uuid:6747c249-2b92-486b-a0a5-574b5243a443","http://resolver.tudelft.nl/uuid:6747c249-2b92-486b-a0a5-574b5243a443","Transformatiemeter kantoren","Geraedts, Rob P. (TU Delft Design & Construction Management); van der Voordt, Theo (TU Delft Real Estate Management); Espinal, Lizanne (Student TU Delft)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Hoe kun je als eigenaar, potentiële koper, ontwikkelaar of investeerder weten of een leegstaand kantoorgebouw geschikt is voor herbestemming naar woningen, en of dit functioneel, technisch en financieel haalbaar is? Een belangrijke vraag, zeker in een periode van veel leegstand en een grote vraag naar woningen. Dit hoofdstuk bespreekt de zogenoemde transformatiemeter, een checklist waarmee kan worden bepaald welke kenmerken van de markt, de locatie, het gebouw en betrokken partijen gunstig of ongunstig zijn voor succesvolle transformatie, mogelijke risico’s en hoe deze risico’s gereduceerd kunnen worden. De transformatiemeter is gefaseerd van snel en globaal naar meer gedetailleerd. Voorts wordt de rol van dit instrument besproken in de besluitvorming over een go/no-go: doorgaan met verdere planontwikkeling, of stoppen met onderzoek naar haalbaarheid. Het hoofdstuk sluit af met een korte bespreking van enkele andere instrumenten om de kansen, obstakels en risico’s van herbestemming in kaart te brengen.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Design & Construction Management","","",""
"uuid:b30543c0-7c0e-4cb2-8a3f-5c784032da32","http://resolver.tudelft.nl/uuid:b30543c0-7c0e-4cb2-8a3f-5c784032da32","Introduction: Shock chains and parallel shocks: Towards a social science of the recovery society","Bryson, John R. (University of Birmingham); Andres, Lauren (University College London (UCL)); Ersoy, A. (TU Delft Urban Development Management); Reardon, Louise (University of Birmingham)","Andres, Lauren (editor); Bryson, John R. (editor); Ersoy, Aksel (editor); Reardon, Louise (editor)","2024","Any one shock is never isolated from other shocks and any one recovery process will be complicated by further related and unrelated shocks and their related recovery processes. This chapter highlights the interactions that occur between shocks that are experienced in parallel or simultaneously and those that occur linearly and take the form of shock chains. These shock processes suggest that there needs to be further social science research on the complexity of shock and related recovery processes, to contribute to academic debate, but also to inform practice, policy development, and implementation. There needs to be a new social science research agenda on characterizing the features of the recovery society. A key issue is that there are many alternative recovery pathways and that each emerges through a set of iterative relationships between people, place, organisations, institutions, and governance processes. These alternatives reflect path dependency and previous decisions and related investments but are complicated by place-based intersectionality that compounds the ways in which parallel shocks and shock chains, and related recovery processes, interact with one another forming highly contextualised shock-related impacts and which then mediate the impacts of recovery processes in practice.","shocks; recovery processes; shock chains; parallel shocks; recovery society; social order","en","book chapter","Edward Elgar Publishing","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-12","","","Urban Development Management","","",""
"uuid:6abe4e7a-fbc6-4c8c-8d4e-50d592bb5d9f","http://resolver.tudelft.nl/uuid:6abe4e7a-fbc6-4c8c-8d4e-50d592bb5d9f","Bouwtechnologisch Onderzoek: A, B, C, D, en dan… Ervaringen met de ABCDº-onderzoeksmethode om inzicht te verkrijgen in de toekomstbestendigheid van een gebouwen","Zijlstra, H. (TU Delft Heritage & Architecture)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Sinds 2006 werk ik aan de ontwikkeling en implementatie van een onderzoeksmethode voor de analyse van de architectonische en ruimtelijke kwaliteiten van gebouwen, zodat die een rol kunnen spelen bij planvorming in de toekomst. Door zowel de oorspronkelijke situatie als de veranderingen door de tijd heen in de analyse te betrekken, kan er vervolgens een afgewogen ontwerp worden gemaakt. De elementen waarop beoordeeld wordt, kunnen wisselen. In de ABCDº-onderzoeksmethode (Analyse van Bouwwerken van Context tot Detail in de tijd) worden naast contextuele factoren de architectonische én bouwkundige elementen benoemd (Zijlstra 2009). Andere methoden leggen meer de nadruk op cultuurhistorische waarden (Pereira Roders 2007 en Kuipers en De Jonge 2017). In het onderwijs op de TU Delft (Heritage & Architecture) passen studenten diverse methoden toe bij hun afstudeerprojecten (Clarke, Zijlstra en De Jonge 2019). De ABCDº-methode is ontstaan uit mijn PhD-onderzoek ‘Bouwen in Nederland 1940–1970’ (Zijlstra 2006). Het Stationspostkantoor in Amsterdam was een van de casestudy’s en bleek een goed voorbeeld te zijn om via deze methodiek de kwaliteiten van een gebouw inzichtelijk te maken voordat een eventuele herbestemming plaatsvindt. Helaas werd het Stationspostkantoor uiteindelijk bijna geheel gesloopt. Op de locatie ervan verschenen de bibliotheek (OBA), het conservatorium (ODE) en het hoofdkantoor van Booking.com. Wellicht krijgen deze gebouwen in de loop van de tijd met dezelfde vraag te maken: kan dit ontwerp ook een andere functie dienen en wat kan dan blijven en wat zal er moeten veranderen? Tijdens het symposium ‘Ontwerpen in analogie met het bestaande’, georganiseerd door Architectenweb en Winhov in Pakhuis de Zwijger op 9 oktober 2023, waren de sprekers het erover eens: eerst een gebouw doorgronden voordat er een ontwerp wordt gemaakt voor herbestemming (Architectenweb 2023).","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Heritage & Architecture","","",""
"uuid:04f17320-aecb-40ab-b709-145b98605e76","http://resolver.tudelft.nl/uuid:04f17320-aecb-40ab-b709-145b98605e76","Cultuurhistorische waarde","van Venrooij, R.G.A.M. (TU Delft Support Management in the Built Environment)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","De waarde van een gebouw gaat vaak verder dan slechts het fysieke aspect. Gebouwen dragen historische, sociale en symbolische betekenissen die verweven zijn met de identiteit van de gemeenschap. Het begrip ‘cultuurhistorische waarde’ omvat deze dimensies en vormt een leidraad voor behoud en herbestemming. De uitdagingen van transformatie gaan dan ook verder dan technische aspecten en omvatten vaak complexe maatschappelijke discussies. Maatschappelijke, emotionele, esthetische en functionele waarde spelen een cruciale rol in het besluitvormingsproces rondom transformatie van cultureel erfgoed. In 2000 ontwikkelde Barend Jan Schrieken het instrument de ‘cultuurhistorische waardemeter’, dat een systematische methode geeft voor het besluitvormingsproces van transformatie van kerken. In dit hoofdstuk duiken we dieper in de betekenis van cultuurhistorische waarde, de verschillende classificaties van monumenten in Nederland en het beleid dat de overheid hanteert. Daarnaast wordt een aanvulling gedaan op het bestaande stappenplan van Schrieken. Dit stappenplan biedt structuur in de verschillende fasen van transformatie. Dit hoofdstuk geeft inzicht in de kansen en uitdagingen die gepaard gaan met waardebehoud of –toevoeging van ons cultureel erfgoed.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Support Management in the Built Environment","","",""
"uuid:9396ab69-205f-46b7-ad4b-591b05f613af","http://resolver.tudelft.nl/uuid:9396ab69-205f-46b7-ad4b-591b05f613af","Collectieve woonvormen: Samenwerken aan huisvesting door adaptief hergebruik","Czischke, D.K. (TU Delft Real Estate Management); van Bortel, G.A. (TU Delft Real Estate Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Collectief wonen is aan een opmars bezig in Europa, en zeker in Nederland. Te midden van een ongekende wooncrisis zoeken steeds meer mensen naar mogelijkheden om samen met anderen te voorzien in toekomstbestendige huisvesting. Sleutelwoorden daarbij zijn gemeenschapsgericht, duurzaam en betaalbaar. Maar waarom komen deze initiatieven zo moeilijk van de grond? En wat kunnen we leren van andere Europese landen? Welke potentie biedt het transformeren van bestaande gebouwen naar collectieve woonvormen? Dit hoofdstuk geeft voorbeelden van projecten waarbij gebouwen met een niet-residentiele functie zijn omgebouwd naar woonvormen met collectieve kenmerken. Het hoofdstuk onderzoekt de belangrijkste kenmerken, uitdagingen en kansen van deze transformaties door middel van bestaande literatuur en de bespreking van enkele concrete cases.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Real Estate Management","","",""
"uuid:0066f948-43a4-4125-bb3d-7ab93a79d3f1","http://resolver.tudelft.nl/uuid:0066f948-43a4-4125-bb3d-7ab93a79d3f1","De rol van woningcorporaties bij de transformatie naar woningen","van Bortel, G.A. (TU Delft Real Estate Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Transformatie van gebouwen is geen vastgoedactiviteit waar elke partij zomaar mee aan de slag kan. Er is onder andere kennis nodig van de markt, technische en financiële kennis, kennis van woningexploitatie en van het verbouwen van panden, inzicht in de lokale woningmarkt en de leefbaarheid van buurten. Bovendien is geld nodig voor aankoop, transformatie en beheer. Woningcorporaties zijn organisaties die vanuit hun doelstellingen, marktrol en competenties in aanmerking komen om aan de slag te gaan met transformaties. Maar: corporaties zijn bijzondere organisaties. De afgelopen tien jaar is hun rol veranderd van een speler met een ruim mandaat en een breed palet aan vastgoedactiviteiten, naar een positie met meer focus op de huisvesting van huurders met een laag inkomen of huishoudens die om andere redenen een kwetsbare positie hebben op de woningmarkt. Transformatie van vastgoed naar woningen is voor corporaties nog steeds mogelijk, mits dat past binnen hun wettelijke mogelijkheden en eigen doelstellingen.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Real Estate Management","","",""
"uuid:373f8858-8196-4af2-8ef9-8cbbe6d0f55e","http://resolver.tudelft.nl/uuid:373f8858-8196-4af2-8ef9-8cbbe6d0f55e","Transformatiewaarde","Remøy, H.T. (TU Delft Real Estate Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Transformatie van een gebouw vindt plaats als een of meerdere actoren vinden dat het gebouw voldoende waarde en kwaliteit heeft om in de toekomst nieuw gebruik te huisvesten. De drijfveren voor transformatie zijn zowel maatschappelijk als financieel en functioneel van aard. Een voorbeeld van maatschappelijke drijfveren is de vraag naar binnenstedelijk wonen en het overheidsbeleid dat deze interesse versterkt, zoals de ladder voor duurzame verstedelijking (Ministerie van Infrastructuur en Waterstaat 2017). Na periodes van leegstand en verwaarlozing kan transformatie duurzame stedelijke intensivering bevorderen (Bryson 1997). In Nederland en internationaal is hergebruik van overtollige kantoorgebouwen een belangrijke drijfveer, bijvoorbeeld door de vraag naar woningen en een verouderde kantorenvoorraad in oudere kantorenwijken (Clifford et al. 2019; Remøy 2010). Tijdelijke transformatie wordt ook ingezet om tijdelijke woningen te creëren, bijvoorbeeld voor studenten en vluchtelingen. Daarnaast wordt tijdelijke transformatie vaak ingezet als strategie om gebiedstransformaties op gang te brengen (Wilkinson et al. 2021; Mazzarella et al. 2022). Transformatie levert vaak indirecte waarde op in de vorm van waardestijging van vastgoed rondom een getransformeerd gebouw. Dit roept de vraag op: wie profiteert en wie betaalt? In dit hoofdstuk worden de waardeaspecten van transformatie uiteengezet, met een focus op transformatie van erfgoed.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Real Estate Management","","",""
"uuid:c0ee724f-8b8b-4172-b286-a34d127afcc1","http://resolver.tudelft.nl/uuid:c0ee724f-8b8b-4172-b286-a34d127afcc1","De rol van burgerparticipatie","van Bortel, G.A. (TU Delft Real Estate Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Burgerberaden, ook wel burgerfora genoemd, worden steeds vaker gezien als instrument om bewoners te laten meepraten en meedenken over complexe maatschappelijke problemen, zoals duurzaamheid, wonen en klimaatverandering. Dit hoofdstuk verkent de mogelijkheden om burgerberaden in te zetten als instrument om het transformeren van gebouwen naar woningen te bevorderen. Dit vanuit de hypothese dat het tempo van veel nieuwbouw-, renovatie- én transformatieprocessen niet zozeer wordt bepaald door technische of financiële uitdagingen, maar door de tijd die we in Nederland nodig hebben voor participatie- en besluitvormingsprocessen.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Real Estate Management","","",""
"uuid:301a1d18-f95f-4774-a2d1-9fe9030936b2","http://resolver.tudelft.nl/uuid:301a1d18-f95f-4774-a2d1-9fe9030936b2","Circulaire en aanpasbare gebouwtransformatie: Een overzicht van strategieën","Hamida, M.B. (TU Delft Real Estate Management); Gruis, V.H. (TU Delft Real Estate Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Bevolkingsgroei, marktdynamiek, vastgoedleegstand en veroudering van gebouwen zijn enkele aanleidingen voor transformatie van gebouwen. De laatste decennia zijn er al veel transformatieprojecten uitgevoerd, mede als oplossing voor leegstand (zie 11. Transformatiemeter kantoren). Sinds kort wordt gebouwtransformatie ook als een veelbelovend onderdeel van de transitie naar een circulaire economie gezien, omdat er per definitie sprake is van hergebruik van materialen en producten en dit de noodzaak om nieuwe materialen in de kringloop te brengen vermindert. Om een optimale bijdrage te leveren aan de circulaire economie, zullen de gebouwtransformaties zelf evenwel ook circulair moeten worden uitgevoerd. Dit hoofdstuk presenteert daarom een conceptueel model voor praktische en toepasbare strategieën voor circulaire en aanpasbare gebouwtransformatie. Dit model is een handig en informatief hulpmiddel voor beleggers, ontwerpers, ontwikkelaars en bouwers.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Real Estate Management","","",""
"uuid:a1de5475-8ca8-49a9-b4da-68aab73b25d3","http://resolver.tudelft.nl/uuid:a1de5475-8ca8-49a9-b4da-68aab73b25d3","De markt voor transformatie naar woningen","Boelhouwer, P.J. (TU Delft Real Estate Management); Remøy, H.T. (TU Delft Real Estate Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","De woningmarkt is sinds het einde van de economische recessie in 2014 sterk verkrapt en heeft zich de afgelopen jaren ontwikkeld tot een aanbiedersmarkt. Hierbij is er een tekort aan woningen in verschillende categorieën. De vraag is of naast nieuwbouw en een betere inzet van de bestaande woningvoorraad ook transformatie van bestaande gebouwen een oplossing kan bieden om het huidige woningtekort terug te dringen. Dit hoofdstuk staat allereerst stil bij de vraag-aanbodverhoudingen op de woningmarkt. Aansluitend hierop worden marktaspecten van transformatie toegelicht. Tot slot volgt een reflectie op voorwaarden vanuit de markt voor succesvol transformeren van leegstaand vastgoed tot woningen.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Real Estate Management","","",""
"uuid:f713493f-80a6-4c58-9eac-4a6004229249","http://resolver.tudelft.nl/uuid:f713493f-80a6-4c58-9eac-4a6004229249","Financiële haalbaarheid bij transformatie naar woningen: Baat het niet, dan gaat het niet","de Jong, P. (TU Delft Design & Construction Management); Peeters, M.U.J. (TU Delft Real Estate Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","De transformatie van kantoren naar residentiële ruimtes is een belangrijk onderwerp in de context van de huidige woningnood en stedelijke regeneratie. Deze transformatie omvat diverse financiële aspecten die zowel kansen als uitdagingen bieden voor ontwikkelaars. Wanneer er puur wordt gekeken naar de financiële haalbaarheid van een transformatieproject is er steeds een uitdaging (Geraedts & Van der Voordt 2004). De opportuniteit van de transformatie zit in het maximaal hergebruiken wat er reeds aanwezig is. Dit om zowel duurzame als circulaire doelstellingen te verwezenlijken. Echter vanuit een puur financieel perspectief is dit niet altijd even eenvoudig. Bestaande bouwstructuren leggen randvoorwaarden op aan het project die tot suboptimale eindresultaten kunnen leiden na transformatie. Wanneer er dan enkel een financiële waardebepaling wordt gemaakt, zoals deze vandaag gangbaar is op de markt, kan het project niet de gewenste rendementen halen. De sleutel zit in de waardebepaling, die zowel een financiële als een maatschappelijke component moet bevatten (Remøy & Van der Voordt 2007). Alleen een integrale afweging leidt tot een gedegen inzicht in de haalbaarheid van toekomstbestendige (transformatie)projecten.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Design & Construction Management","","",""
"uuid:ca66aeea-5cc4-4e0a-82ef-d441545e841c","http://resolver.tudelft.nl/uuid:ca66aeea-5cc4-4e0a-82ef-d441545e841c","Juridisch Kader: Regels voor de transformatie naar woningen in de Omgevingswet","Hobma, Fred (TU Delft Design & Construction Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Dit hoofdstuk bespreekt regels die van toepassing zijn op transformatie van gebouwen naar woningen onder de nieuwe Omgevingswet. De focus ligt op drie onderdelen: (1) de juridisch-planologische procedures die gevolgd moeten worden voor transformatie; (2) het technische kwaliteitsniveau waaraan de nieuwe woningen moeten voldoen; (3) participatieverplichtingen bij transformatieprojecten. De participatieverplichtingen zijn nieuw ten opzichte van eerdere wetgeving. De regels voor transformatie hebben betrekking op de procedures die gevolgd moeten worden en op het minimum kwaliteitsniveau van het transformatieontwerp. Kennisneming van de regels is belangrijk omdat de procedures invloed hebben op het tijdsverloop en de kwaliteitseisen invloed hebben op de kosten van een transformatieproject.","","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Design & Construction Management","","",""
"uuid:9e02d17c-9912-473e-8eb1-bffdeaaae44c","http://resolver.tudelft.nl/uuid:9e02d17c-9912-473e-8eb1-bffdeaaae44c","Negotiating Visions of Waste: On the Ethics of Maintaining Waste Infrastructures","Alleblas, J. (TU Delft Ethics & Philosophy of Technology); Hofbauer, B. (TU Delft Ethics & Philosophy of Technology)","Coeckelbergh, Mark (editor); Young, Mark Thomas (editor)","2024","This chapter focuses on the maintenance of waste infrastructures in urban areas, arguing that waste infrastructures and their maintenance should be made more visible to allow for a more extensive, ethical engagement with waste. This contribution claims that cities need to approach the (re)design of municipal waste infrastructures through dynamic maintenance and reflexive repair, wherein waste, repair and maintenance are understood as discursive processes. Waste infrastructures and their maintenance are mostly invisible in daily interactions in cities in High-Income Countries, despite the diversities in waste practices, such as collection and processing. Invisibility is an intended outcome of the design and operation of these infrastructures, stemming from a nineteenth-century waste imaginary called ‘the tidy city’. Current municipal waste infrastructures are kept invisible, upholding beliefs and practices that disvalue waste. While visions have been proposed that challenge this disvalue, few of them have been able to materialise in stratified municipal waste management systems. This engagement is seen as a first step in challenging modern notions of dirt and waste. Visibility is a (new) design criterion for municipal waste infrastructures, a criterion that the authors relate to waste-affirming beliefs and practices, elaborating on anthropological perspectives on dirt and waste.
2-equivalent for the 3.5 °C, 2.0 °C, and 1.5 °C scenarios, respectively. The paper examines challenges in achieving these scenarios, noting that electrolysis-based (yellow) ammonia, contingent on electricity decarbonisation, offers a cleaner production pathway. However, achieving significant GHG reductions is complex, requiring advancements in technologies with lower readiness, like carbon capture and storage and methane pyrolysis. The study also discusses limitations such as the need to reduce urea demand, potential growth in ammonia as a fuel, reliance on CO2 transport and storage, expansion of renewable energy, raw material scarcity, and the longevity of existing plants. It highlights potential shifts in environmental impacts, such as increased land, metal, and mineral use in scenarios with growing renewable electricity and bioenergy with carbon capture and storage.","Ammonia; Fertilizer; IEA roadmap; IMAGE; Prospective LCA; Scenarios","en","journal article","","","","","","","","","","","Energy Technology","","",""
"uuid:3ca0a48c-43a3-4b8b-ba00-c28403fc19fd","http://resolver.tudelft.nl/uuid:3ca0a48c-43a3-4b8b-ba00-c28403fc19fd","3D printer-driven design of a non-assembly titanium surgical instrument using compliant lattice flexures","Lussenburg, K.M. (TU Delft Medical Instruments & Bio-Inspired Technology); van Starkenburg, R.I.B. (TU Delft EMSD EEMCS Project technicians); Sakes, A. (TU Delft Medical Instruments & Bio-Inspired Technology); Breedveld, P. (TU Delft Medical Instruments & Bio-Inspired Technology)","","2024","Metal additive manufacturing is a promising technology for the production of functional medical products, due to its high shape complexity and resolution, and ability to withstand sterilization temperatures. This study explores the possibility of designing a completely non-assembly steerable surgical instrument using Selective Laser Melting. Despite its advantages for medical devices, the rough surface quality of unfinished parts can be problematic for non-assembly designs, leading to increased friction and wear in rigid body mechanisms and tendon-actuated mechanisms. We investigated printing of rolling contact joints with crossed flexures as low-friction joints, adjusted for printing in titanium for the design of the instrument. Grid-based lattice structures were incorporated as miniature flexures, and we explored the influence of various grid sizes on the flexibility and bending stiffness of the lattices. Based on this exploration, we altered the rolling joint configuration from two crossed flexures to a single straight flexure for our design. The resulting steerable surgical instrument design is completely non-assembly, including its actuation, facilitates easy removal of support structures, and requires no surface finishing steps. It has a diameter of less than 20 mm, facilitates opening and closing of a grasper, and steering of the grasper by 20 degrees.","Compliant; Lattice; Non-assembly; Selective laser melting; Surgical instrument","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:906c207d-1f64-46dd-b601-56cefa947f37","http://resolver.tudelft.nl/uuid:906c207d-1f64-46dd-b601-56cefa947f37","3D-printing allows for fluid-controlled linear actuators with unconventional shapes","Zillen, Eva (Student TU Delft); van der Windt, B. (TU Delft Medical Instruments & Bio-Inspired Technology); Vallery, H. (TU Delft Biomechatronics & Human-Machine Control; Rheinisch-Westfälische Technische Hochschule); Smit, G. (TU Delft Medical Instruments & Bio-Inspired Technology)","","2024","Background: Pneumatic actuators are widely used in applications like (medical) robots, or prostheses. Pneumatic actuators require a complex manufacturing process and are produced in standardized dimensions to reduce costs. Over the last decade 3D-printing has emerged as a cost-effective and efficient production method in medical applications. 3D-printing can also function as a cost-efficient alternative production method for pneumatic actuators. Objective: The goal of this research is to study the possibility of creating a pneumatic linear actuator with 3D-printing. Furthermore, the aim is to use the advantage of 3D-printing to create pneumatic actuators with non-circular cross-sections. Methodology: To evaluate the performance of a 3D-printed pneumatic actuator, a test setup was designed and built to measure the leakage and sliding friction force. Furthermore, two pneumatic actuators with a non-conventional cross-sectional shape were designed and their performance was tested and compared with a 3D-printed cylindrical pneumatic actuator, since these tests only ran once, the results are more a guideline. During the manufacturing of the cylinders, no post-processing techniques were used. Results: The functioning of a 3D-printed circular pneumatic actuator was proven with low static leakage rates of 2.5%, low dynamic leakage rates of approximately 1%, and a maximum friction force of [Formula presented]. Furthermore, the results show that it is possible to print functioning pneumatic cylinders with a non-cylindrical concave cross-section. The non-conventional cylinders were tested up to [Formula presented] with maximum dynamic leakage of [Formula presented]. Conclusion: This study demonstrates a method to create functional pneumatic linear actuators with 3D-printing. It was possible to create 3D-printed actuators with a conventional shape, e.g. circular and unconventional shapes e.g. stadium/oval shape and a kidney shape. The leak rates for conventional and unconventional shapes were in the same range. This opens up the world for more design freedom in pneumatic actuators.","3D-printing; Additive manufacturing; Gas springs; Hydraulic actuators; Piston-cylinder systems; Pneumatic actuators; Shape-independent pneumatic actuators","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:da47e20a-dbd0-40d2-bf14-a31af0bf8b93","http://resolver.tudelft.nl/uuid:da47e20a-dbd0-40d2-bf14-a31af0bf8b93","3D magnetic seed localization for augmented reality in surgery","Ambrosini, P. (TU Delft Computer Graphics and Visualisation; Erasmus MC); Azizian Amiri, S. (TU Delft Medical Instruments & Bio-Inspired Technology); Zeestraten, Eliane (Amphia Hospital); van Ginhoven, Tessa (Erasmus MC); Marroquim, Ricardo (TU Delft Computer Graphics and Visualisation); van Walsum, T. (Erasmus MC)","","2024","Purpose: For tumor resection, surgeons need to localize the tumor. For this purpose, a magnetic seed can be inserted into the tumor by a radiologist and, during surgery, a magnetic detection probe informs the distance to the seed for localization. In this case, the surgeon still needs to mentally reconstruct the position of the tumor from the probe’s information. The purpose of this study is to develop and assess a method for 3D localization and visualization of the seed, facilitating the localization of the tumor. Methods: We propose a method for 3D localization of the magnetic seed by extending the magnetic detection probe with a tracking-based localization. We attach a position sensor (QR-code or optical marker) to the probe in order to track its 3D pose (respectively, using a head-mounted display with a camera or optical tracker). Following an acquisition protocol, the 3D probe tip and seed position are subsequently obtained by solving a system of equations based on the distances and the 3D probe poses. Results: The method was evaluated with an optical tracking system. An experimental setup using QR-code tracking (resp. using an optical marker) achieves an average of 1.6 mm (resp. 0.8 mm) 3D distance between the localized seed and the ground truth. Using a breast phantom setup, the average 3D distance is 4.7 mm with a QR-code and 2.1 mm with an optical marker. Conclusion: Tracking the magnetic detection probe allows 3D localization of a magnetic seed, which opens doors for augmented reality target visualization during surgery. Such an approach should enhance the perception of the localized region of interest during the intervention, especially for breast tumor resection where magnetic seeds can already be used in the protocol.","3D localization; Magnetic seed; Mixed-reality; Surgery","en","journal article","","","","","","","","","","","Computer Graphics and Visualisation","","",""
"uuid:95d04d2d-5fec-4bec-9ba7-839c0732c6a9","http://resolver.tudelft.nl/uuid:95d04d2d-5fec-4bec-9ba7-839c0732c6a9","Development of a Geo to BIM Converter: CityJSON Importer Plugin for Autodesk Revit","Hakim, Amir (TU Delft Urban Data Science); van der Vaart, J.A.J. (TU Delft Urban Data Science); Arroyo Ohori, G.A.K. (TU Delft Urban Data Science); Stoter, J.E. (TU Delft Urban Data Science)","Kolbe, Thomas H. (editor); Donaubauer, Andreas (editor); Beil, Christof (editor)","2024","The integration of 3D city models and Building Information Models (BIM) in the context of GeoBIM has gained significant attention from both academia and industry. Harmonizing the distinct characteristics and goals of these models is crucial for successful integration. In this paper, we present the development of a plugin for Autodesk Revit, a popular BIM platform, which allows for the incorporation of 3D Geo-data encoded in CityJSON. The plugin, published as open source, enables the generation of individual geometries with associated city model attributes as parameters, facilitating analysing the impact of new or changed buildings (modelled in BIM) on the environment (captured in geo-data). Challenges addressed during development include georeferencing, data format import, handling different geometry approaches, hierarchy of attributes, code optimization, user-friendliness, and enhanced visualization. The plugin contributes to the seamless integration of geo- and BIM data, enhancing interoperability and supporting informed decision-making in the Architecture, Engineering, and Construction and urban domains.","Building information modelling; Georeferencing; Interoperability; CityJSON; 3D city models","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-21","","","Urban Data Science","","",""
"uuid:ed7b6aaf-1085-47ac-8e8f-c15315c5889a","http://resolver.tudelft.nl/uuid:ed7b6aaf-1085-47ac-8e8f-c15315c5889a","The flexible airport bus and last-mile ride-sharing problem: Math-heuristic and metaheuristic approaches","He, P. (Shanghai Jiao Tong University); Jin, Jian Gang (Shanghai Jiao Tong University); Schulte, F. (TU Delft Transport Engineering and Logistics)","","2024","Airport buses play a crucial role in addressing the last-mile problem of air travel, especially in cities and countries lacking inner-city rail transit systems. Nevertheless, airport buses are currently witnessing a decline in ridership due to drawbacks such as long departure intervals, inflexible stops, and considerable distances between stops. Consequently, delivering high-quality airport bus services has become a pressing concern for public transport operators. Motivated by new flexible buses and ride-sharing services, this paper explores a flexible airport bus service that integrates ride-sharing services for passengers traveling from bus stops to their destinations. This problem entails integrated decisions involving bus stop selection, passenger assignment to drop-off bus stops, as well as bus and ride-sharing routing. Accordingly, this problem presents more challenges in decision-making than traditional flexible bus or ride-sharing routing problems. We first develop an arc-based mixed-integer linear programming model. Subsequently, we design a double decomposition math-heuristic algorithm that builds upon logic-based Benders decomposition and column generation algorithms to obtain a near-optimal solution within practical computation time limits for practical-scale instances. Additionally, we implement an adaptive large neighborhood search algorithm to evaluate the solution quality of this math-heuristic algorithm and to solve large-scale instances. To validate the effectiveness of both the model and the algorithms, we conduct numerical experiments using instances derived from Shenzhen airport bus lines. The experimental results demonstrate that the flexible service mode offers significant advantages in reducing both passenger ride time and vehicle mileage over traditional airport bus or taxi modes.","Column generation; Double decomposition math-heuristic; Flexible airport bus; Last-mile ride-sharing; Logic-based Benders decomposition; Routing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-19","","","Transport Engineering and Logistics","","",""
"uuid:f09f57c2-6ad8-4da7-9680-c3b40423a74a","http://resolver.tudelft.nl/uuid:f09f57c2-6ad8-4da7-9680-c3b40423a74a","Assessment of the LoD Specification for the Integration of BIM-Derived Building Models in 3D City Models","van der Vaart, J.A.J. (TU Delft Urban Data Science); Stoter, J.E. (TU Delft Urban Data Science); Diakite, A.A. (University of New South Wales); Biljecki, F. (National University of Singapore); Arroyo Ohori, G.A.K. (TU Delft Urban Data Science); Hakim, Amir (TU Delft Urban Data Science)","Kolbe, Thomas H. (editor); Donaubauer, Andreas (editor); Beil, Christof (editor)","2024","Although level of detail (LoD) is a central concept in 3D city modelling, specifying different LoDs in an unambiguous manner is not straightforward. To resolve this, a set of frameworks have been developed. This paper evaluates the suitability of the LoD framework of (Biljecki et al. 2016) for 3D building models that have been generated directly from BIM models. The output of two BIM shell extractors are tested on how well they can be defined by the framework. It was found that although BIM-derived models can be specified by the framework to a certain degree, the framework is not fully capable to also specify lower quality models and to support all the output that may come from BIM shell extractors. This can be resolved by either addressing issues in the shell extractors’ output or in the framework itself. The results of this research can be used to improve the LoD framework and to adjust the shell extractors output to better comply with unambiguous definitions of building models at different LoDs and could be a first step to standardise the conversion of BIM models at different LoDs to be used in urban applications.","LoD framework; 3D city model; BIM envelope extractor","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-21","","","Urban Data Science","","",""
"uuid:4dc2a282-650d-4c1d-92ef-fbfffba41c5b","http://resolver.tudelft.nl/uuid:4dc2a282-650d-4c1d-92ef-fbfffba41c5b","4D-STEM Nanoscale Strain Analysis in van der Waals Materials: Advancing beyond Planar Configurations","Bolhuis, M. (TU Delft QN/Conesa-Boj Lab; Kavli institute of nanoscience Delft); van Heijst, S.E. (TU Delft QN/Conesa-Boj Lab; Kavli institute of nanoscience Delft); Sangers, J.J.M. (TU Delft QN/Conesa-Boj Lab; Kavli institute of nanoscience Delft); Conesa Boj, S. (TU Delft QN/Conesa-Boj Lab; Kavli institute of nanoscience Delft)","","2024","Achieving nanoscale strain fields mapping in intricate van der Waals (vdW) nanostructures, like twisted flakes and nanorods, presents several challenges due to their complex geometry, small size, and sensitivity limitations. Understanding these strain fields is pivotal as they significantly influence the optoelectronic properties of vdW materials, playing a crucial role in a plethora of applications ranging from nanoelectronics to nanophotonics. Here, a novel approach for achieving a nanoscale-resolved mapping of strain fields across entire micron-sized vdW nanostructures using four-dimensional (4D) scanning transmission electron microscopy (STEM) imaging equipped with an electron microscope pixel array detector (EMPAD) is presented. This technique extends the capabilities of STEM-based strain mapping by means of the exit-wave power cepstrum method incorporating automated peak tracking and K-means clustering algorithms. This approach is validated on two representative vdW nanostructures: a two-dimensional (2D) MoS2 thin twisted flakes and a one-dimensional (1D) MoO3/MoS2 nanorod heterostructure. Beyond just vdW materials, the versatile methodology offers broader applicability for strain-field analysis in various low-dimensional nanostructured materials. This advances the understanding of the intricate relationship between nanoscale strain patterns and their consequent optoelectronic properties.","electron microscope pixel array detector (EMPAD); four-dimensional scanning transmission electron microscopy (4D-STEM); strain mapping; van der Waals materials","en","journal article","","","","","","","","","","","QN/Conesa-Boj Lab","","",""
"uuid:dfe34bf0-575f-403b-b949-5ce569c8b57e","http://resolver.tudelft.nl/uuid:dfe34bf0-575f-403b-b949-5ce569c8b57e","Trajectory Hiding and Sharing for Supply Chains with Differential Privacy","Li, T. (TU Delft Cyber Security); Xu, L. (TU Delft Cyber Security; TU Delft Ship Hydromechanics and Structures); Erkin, Z. (TU Delft Cyber Security); Lagendijk, R.L. (TU Delft Cyber Security)","Tsudik, Gene (editor); Conti, Mauro (editor); Liang, Kaitai (editor); Smaragdakis, Georgios (editor)","2024","With the fast development of e-commerce, there is a higher demand for timely delivery. Logistic companies want to send receivers a more accurate arrival prediction to improve customer satisfaction and lower customer retention costs. One approach is to share (near) real-time location data with recipients, but this also introduces privacy and security issues such as malicious tracking and theft. In this paper, we propose a privacy-preserving real-time location sharing system including (1) a differential privacy based location publishing method and (2) location sharing protocols for both centralized and decentralized platforms. Different from existing location perturbation solutions which only consider privacy in theory, our location publishing method is based on a real map and different privacy levels for recipients. Our analyses and proofs show that the proposed location publishing method provides better privacy protection than existing works under real maps against possible attacks. We also provide a detailed analysis of the choice of the privacy parameter and their impact on the suggested noisy location outputs. The experimental results demonstrate that our proposed method is feasible for both centralized and decentralized systems and can provide more precise arrival prediction than using time slots in current delivery systems.","Applied cryptography; Blockchain; Differential privacy; Location privacy; Privacy-preserving","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Cyber Security","","",""
"uuid:2d70b0c5-78c4-46bf-b66e-19d00f3a5458","http://resolver.tudelft.nl/uuid:2d70b0c5-78c4-46bf-b66e-19d00f3a5458","Reducing the Environmental Impact of Syringes at the Intensive Care Unit","Honkoop, Margot (Student TU Delft); Albayrak, A. (TU Delft Applied Ergonomics and Design); Balkenende, R. (TU Delft Circular Product Design); Hunfeld, Nicole (Erasmus MC); Diehl, J.C. (Erasmus MC)","Melles, M. (editor); Goossens, R.H. (editor)","2024","This research project, part of the Green Intensive Care Unit (ICU) initiative at the Erasmus University Medical Center (EMC), is focused on reducing the environmental impact of syringes at the ICU by designing solutions based on circular economy principles. Based on a Material Flow Analysis of the EMC ICU, syringes and their packaging have been identified as one of the main environmental impact hotspots. Therefore, this project aimed to redesign the syringes, their packaging, and their use, according to circular design strategies suitable for medical products to decrease their environmental impact, while remaining convenient and safe in use for the healthcare staff and patients. Research was executed to understand the context from multiple perspectives. The outcomes demonstrated that decreasing the impact of syringes is not only related to the design of the syringe itself. Manufacturing, preparation, use and disposal, all contribute to the environmental impact of the syringe. Various possible interventions were derived to reduce its impact:
1.
Adapting the infection prevention protocol and behaviour of the staff;
2.
Separating infectious waste from general hospital waste;
3.
Redesigning the syringe itself;
4.
Optimising the filling process of syringes.
The final design is an optimised filling process for prefilled sterilised syringes (PFSs), based on circular strategies such as reduce, reuse, rethink and repurpose. Interventions include: eliminating a redundant sterilisation phase, reducing residual medication and changing from steam to gamma sterilisation. This resulted in decreasing the amount of waste, material, energy and water consumption, while offering similar convenience and safety for the staff and patients of the ICU.","Circular healthcare; Syringe; Environmental impact; Design","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-05","","","Applied Ergonomics and Design","","",""
"uuid:dbcc79c3-84c5-41ce-9a84-557773af39e3","http://resolver.tudelft.nl/uuid:dbcc79c3-84c5-41ce-9a84-557773af39e3","Aerodynamic model comparison for an X-shaped vertical-axis wind turbine","Giri Ajay, A. (TU Delft Wind Energy); Morgan, Laurence (University of Strathclyde); Wu, Y. (TU Delft Wind Energy); Bretos, David (Centro Nacional de Energías Renovables); Cascales, Aurelio (Centro Nacional de Energías Renovables); Pires, Oscar (Centro Nacional de Energías Renovables); Ferreira, Carlos (TU Delft Wind Energy)","","2024","This article presents a comparison study of different aerodynamic models for an X-shaped vertical-axis wind turbine and offers insight into the 3D aerodynamics of this rotor at fixed pitch offsets. The study compares six different numerical models: a double-multiple streamtube (DMS) model, a 2D actuator cylinder (2DAC) model, an inviscid free vortex wake model (from CACTUS), a free vortex wake model with turbulent vorticity (from QBlade), a blade-resolved unsteady Reynolds-averaged Navier–Stokes (URANS) model, and a lattice Boltzmann method (from PowerFLOW). All models, except URANS and PowerFLOW use the same blade element characteristics other than the number of blade elements. This comparison covers the present rotor configuration for several tip-speed ratios and fixed blade pitch offsets without unsteady corrections, except for the URANS and PowerFLOW which cover a single case. The results show that DMS and 2DAC models are inaccurate – especially at highly loaded conditions, are unable to predict the downwind blade vortex interaction, and do not capture the vertical/axial induction this rotor exhibits. The vortex models are consistent with each other, and the differences when compared against the URANS and PowerFLOW mostly arise due to the unsteady and flow curvature effects. Furthermore, the influence of vertical induction is very prominent for this rotor, and this effect becomes more significant with fixed pitch offsets where the flow at the blade root is considerably altered.","","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:64563d5b-e4ff-4e7b-b835-947b88063a72","http://resolver.tudelft.nl/uuid:64563d5b-e4ff-4e7b-b835-947b88063a72","Effect of vibrational modes on fluidization characteristics and solid distribution of cohesive micro- and nano-silica powders","Kamphorst, R. (TU Delft ChemE/Product and Process Engineering); Wu, K. (TU Delft ChemE/Product and Process Engineering); van Baarlen, M. (TU Delft Sanitary Engineering); Meesters, G.M.H. (TU Delft ChemE/Product and Process Engineering); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering)","","2024","In this study, the impact of different vibrational modes on the fluidization characteristics of cohesive micro- and nano-silica powder was examined. Fractional pressure drop, bed expansion measurements, and X-ray imaging were utilized to characterize the fluidization quality. The densities of the emulsion phase at the top and bottom of the column were quantified and compared, providing insights into the solid distribution within the fluidized bed. In the absence of vibration, neither powder could be fluidized within the considered range of superficial gas velocities. Vertical vibration was found to initiate fluidization for both powders. In contrast, elliptical vibration failed to overcome the channelling behavior when fluidizing the micro-powder. For nano-powder, combined channelling and powder compaction occurred when the bed was subjected to elliptical vibration. For the micro-powder, it was observed that bed homogeneity was independent of vertical vibration intensity but improved with increasing superficial gas velocity. For nano-powder, intensifying vertical vibration led to segregation, likely due to agglomerate densification. Furthermore, fractional pressure drop measurements proved to be a strong tool in assessing fluidization quality, providing insights that could not be attained by conventional indicators.","Agglomeration; Assistance methods; Cohesive particles; Nano-particles; Vibro-fluidized bed; X-ray imaging","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:c20dc01b-0580-44f5-aa29-9f1d998a4d72","http://resolver.tudelft.nl/uuid:c20dc01b-0580-44f5-aa29-9f1d998a4d72","Noncompact uniform universal approximation","van Nuland, T.D.H. (TU Delft Analysis)","","2024","The universal approximation theorem is generalised to uniform convergence on the (noncompact) input space Rn. All continuous functions that vanish at infinity can be uniformly approximated by neural networks with one hidden layer, for all activation functions φ that are continuous, nonpolynomial, and asymptotically polynomial at ±∞. When φ is moreover bounded, we exactly determine which functions can be uniformly approximated by neural networks, with the following unexpected results. Let Nφl(Rn)¯ denote the vector space of functions that are uniformly approximable by neural networks with l hidden layers and n inputs. For all n and all l≥2, Nφl(Rn)¯ turns out to be an algebra under the pointwise product. If the left limit of φ differs from its right limit (for instance, when φ is sigmoidal) the algebra Nφl(Rn)¯ (l≥2) is independent of φ and l, and equals the closed span of products of sigmoids composed with one-dimensional projections. If the left limit of φ equals its right limit, Nφl(Rn)¯ (l≥1) equals the (real part of the) commutative resolvent algebra, a C*-algebra which is used in mathematical approaches to quantum theory. In the latter case, the algebra is independent of l≥1, whereas in the former case Nφ2(Rn)¯ is strictly bigger than Nφ1(Rn)¯.","Deep learning; Feedforward ANN; Functional analysis; Ridge functions; Uniform convergence; Universal approximation theorem","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-25","","","Analysis","","",""
"uuid:55c2d2db-32f7-4ad7-a51c-0af839d7efc0","http://resolver.tudelft.nl/uuid:55c2d2db-32f7-4ad7-a51c-0af839d7efc0","A generating absorbing boundary condition for simulating wave interaction with maritime structures in current or at forward speed","Chang, X. (Shanghai Ship and Shipping Research Institute Co.); Wellens, P.R. (TU Delft Ship Hydromechanics and Structures)","","2024","The lack of suitable boundary conditions in practical surface wave simulations with maritime structures in current or at forward speed may cause energy in the computational domain to accumulate due to spurious wave reflection. The common way to prevent wave reflection is to use passive wave absorbers, such as damping zones or relaxation zones, which requires larger domains at the cost of computational effort. Our goal is to derive a local generating absorbing boundary condition (GABC) for long-crested irregular waves on top of a mean flow, using the flow to model the forward speed of a structure such as a ship. Earlier work has demonstrated that a local GABC for free surface waves has a performance similar to passive wave absorbers, but at a reduced computational effort. New in the present work is that we extend, verify and validate the GABC in the presence of a nonzero mean flow. The GABC is designed to be accurate for a range of wave components in irregular sea states, with the resulting reflection coefficients for each component lower than a chosen value, say 5%. Having used potential flow theory for its derivation means that the boundary should not be placed at the exact location where wave breaking is expected, such as very close to the structure in the domain, or in the surf zone in coastal modeling. For the application with ships in this article that does not pose a limitation. The performance is demonstrated for a range of dimensionless wave number between 0 and 6. Such a boundary condition is obtained through a rational approximation of the linear dispersion relation with a mean flow, in combination with vertical derivatives of the solution variables along the boundary. Local linearization means that the GABC incorrectly considers bound, nonlinear wave components to be freely propagating wave components. Bound components, however, tend to have smaller amplitudes and do not appear to affect performance for the considered cases. Results of simulations with regular and irregular waves, on top of flows with different magnitudes and directions, are found to agree with the theory. The main source of differences is the implementation of the second derivate in the GABC near the free surface. Simulations of a Wigley hull at forward speed in irregular waves are compared to an experiment that was conducted specifically for validating the ABC. The data of the experiment are available as open data through doi: 10.4121/21320604. The comparison between simulation and experiment demonstrates that the GABC with a mean flow can be applied not only for theoretical simulations with propagating waves, but also for more practical applications with a structure in the domain.","Absorbing boundary condition; Combined waves and mean flow; Doppler shift; Volume of Fluid (VoF); Wave dispersion","en","journal article","","","","","","","","","","","Ship Hydromechanics and Structures","","",""
"uuid:fb6fc6bc-4734-4e0a-ac86-d8b6cb9f4ebf","http://resolver.tudelft.nl/uuid:fb6fc6bc-4734-4e0a-ac86-d8b6cb9f4ebf","Real-World Applications of Artificial Intelligence in Architecture","Bier, H.H. (TU Delft Building Knowledge); Hidding, A.J. (TU Delft Building Knowledge); Khademi, S. (TU Delft Building Knowledge); van Engelenburg, C.C.J. (TU Delft Building Knowledge); Prendergast, J.M. (TU Delft Human-Robot Interaction); Peternel, L. (TU Delft Human-Robot Interaction)","Arai, Kohei (editor)","2024","Real-world applications of Artificial Intelligence (AI) in architecture have been explored more recently at Technical University (TU) Delft by integrating AI in Design-to-Robotic-Production-Assembly and -Operation (D2RPA&O) methods. These embed robotics into building processes and buildings by linking computational design with robotic construction and/ or operation of building components and buildings. This paper presents two case studies in which AI-supported D2RA is implemented in a multidisciplinary approach that requires the integration of research domains such as architecture, robotics, computer and material science.","architectural design; robotic construction; computer vision; human-robot interaction; deep learning","en","conference paper","Springer Nature","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-14","","","Building Knowledge","","",""
"uuid:01419615-9a1d-428d-8769-a96ab9498a6c","http://resolver.tudelft.nl/uuid:01419615-9a1d-428d-8769-a96ab9498a6c","How well do NDVI and OpenStreetMap data capture people’s visual perceptions of urban greenspace?","Teeuwen, R.F.L. (TU Delft Human-Centred Artificial Intelligence); Milias, V. (TU Delft Human-Centred Artificial Intelligence); Bozzon, A. (TU Delft Human-Centred Artificial Intelligence); Psyllidis, A. (TU Delft Internet of Things)","","2024","The study of urban greenspaces typically relies on three types of data: people’s subjective perceptions collected via questionnaires, vegetation indices derived from satellite imagery, such as the Normalized Difference Vegetation Index (NDVI), and Land Use or Land Cover maps, such as OpenStreetMap (OSM). Data on people’s perceptions are essential when researching human activities, yet they scale poorly. NDVI and OSM data, on the other hand, are freely available worldwide, thus valuable for assessing cities at scale or prioritizing locations for interventions. However, it is unclear how effectively NDVI and OSM data capture people’s visual perceptions of urban greenspaces. In this work, we collect people’s visual perceptions of public spaces in three major European cities through crowdsourcing, quantitatively compare them to NDVI and OSM data, and qualitatively investigate disparities. We found that NDVI moderately correlates with perceived greenness and that not only OSM greenspaces but also pocket parks and play spaces are often considered green. Furthermore, we found that people’s perceptions correspond best to OSM data in small radius distances and NDVI data in larger radius distances and that combining NDVI and OSM data can improve identification of places in OSM that are commonly considered green. Our qualitative analysis revealed that configuration and variety of vegetation, and presence of other natural or built-up features, influence people’s perceptions of greenspace. With our findings we aim to help researchers and practitioners make more informed decisions when collecting greenspace data for their specific context, ultimately contributing to green urban environments that reflect people’s perspectives.","Urban greenspace; Visual perception; OpenStreetMap; NDVI; Crowdsourcing","en","journal article","","","","","","","","","","","Human-Centred Artificial Intelligence","","",""
"uuid:81bbc3bc-4ecf-4606-b100-4cb7e837c29b","http://resolver.tudelft.nl/uuid:81bbc3bc-4ecf-4606-b100-4cb7e837c29b","Comprehensive properties assessment of asphalt binder under aqueous solutions with different pH values and its gradient damage behaviors","Zou, Yingxue (Wuhan University of Technology); Wu, Shaopeng (Wuhan University of Technology); Chen, Anqi (Wuhan University of Technology); Liu, Quantao (Wuhan University of Technology); Amirkhanian, Serji (University of Alabama); Xu, S. (TU Delft Materials and Environment; Wuhan University of Technology); Yang, Chao (Hubei University of Technology); Wan, Pei (Wuhan University of Technology); Xu, Haiqin (Wuhan University of Technology); Lu, Ziyu (Wuhan University of Technology)","","2024","This study characterized the morphology, high-temperature property, rheological property, adhesion, cohesion, and chemical component of asphalt binder under aqueous solutions of different pH values. Then the physicochemical properties of asphalt binder were comprehensively evaluated by the improved radar chart. The properties of asphalt binder stripped layer-by-layer were explored to elucidate its gradient damage behaviors. The results indicate that the pH 3 solution reveals the greatest impact on the morphology of 90 asphalt (90 A) and styrene-butadiene-styrene modified asphalt (SBS MA), leading to the wide cracks on 90 A and the network cracks on SBS MA. The comprehensive assessment index of 90 A exposed to pH 3, pH 5, pH 7, pH 9, and pH 11 solutions can be reduced by 20.8%, 20.2%, 1.5%, 14.0%, and 25.5%, respectively. While for SBS MA, its corresponding values variation are 23.2%, 17.7%, 4.6%, 8.7%, and 13.0%, respectively. The acid solutions significantly affect the comprehensive properties of 90 A, but their pH value has little effect. 90 A exposure to the higher pH value of alkali solution reveals the worse comprehensive properties. Acid solute and alkali solute can aggravate the effect of aqueous solution on the comprehensive properties of SBS MA, and the degree of aggravation increases with the increase of solute concentration. The properties of asphalt binders exhibit varied gradient damage behaviors under different solute environments. The most serious damage occurs at 25–50 µm of 90 A and 0–50 µm of SBS MA. This study facilitates an accurate understanding of the mechanism of pavement distresses and composition design and construction utilization of asphalt binders.","Aqueous solutions; Asphalt binder; Comprehensive assessment; Gradient damage behaviors; pH value","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-17","","","Materials and Environment","","",""
"uuid:cc6842c0-23d3-40c6-be10-f93f8dee55fc","http://resolver.tudelft.nl/uuid:cc6842c0-23d3-40c6-be10-f93f8dee55fc","Integrating post-event very high resolution SAR imagery and machine learning for building-level earthquake damage assessment","Macchiarulo, V. (TU Delft Geo-engineering); Giardina, Giorgia (TU Delft Geo-engineering); Milillo, Pietro (University of Houston; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Aktas, Yasemin D. (University College London (UCL)); Whitworth, Michael R.Z. (AECOM Technology Corporation, United Kingdom)","","2024","Earthquakes have devastating effects on densely urbanised regions, requiring rapid and extensive damage assessment to guide resource allocation and recovery efforts. Traditional damage assessment is time-consuming, resource-intensive, and faces challenges in covering vast affected areas, often limiting timely decision-making. Space-borne synthetic aperture radars (SAR) have gained attention for their all-weather and day-night imaging capabilities. These advantages, coupled with wide coverage, short revisits and very high resolution (VHR), have created opportunities for using SAR data in disaster response. However, most SAR studies for post-earthquake damage assessment rely on change detection methods using pre-event SAR images, which are often unavailable in operational scenarios. Limited studies using solely post-event SAR data primarily concentrate on city-block-level damage assessment, thus not fully exploiting the VHR SAR potential. This paper presents a novel method integrating solely post-event VHR SAR imagery and machine learning (ML) for regional-scale post-earthquake damage assessment at the individual building-level. We first used supervised learning on case-specific datasets, and then introduced a combined learning approach, incorporating inventories from multiple case studies to assess generalisation. Finally, the ML model was tested on unseen study areas, to evaluate its flexibility in unfamiliar contexts. The method was implemented using datasets collected during the Earthquake Engineering Field Investigation Team (EEFIT) reconnaissance missions following the 2021 Nippes earthquake and the 2023 Kahramanmaraş earthquake sequence. The results demonstrate the method’s ability to classify standing and collapsed buildings, achieving up to 72% overall accuracy on unseen regions. The proposed method has potential for future disaster assessments, thereby contributing to more effective earthquake management strategies.","Disaster management; ML techniques; Post-earthquake reconnaissance; Remote sensing; Synthetic aperture radar; Texture analysis","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:4913ee24-246f-4515-bcc7-b92efa04f7c8","http://resolver.tudelft.nl/uuid:4913ee24-246f-4515-bcc7-b92efa04f7c8","Isolated propeller aeroacoustics at positive and negative thrust","Goyal, J. (TU Delft Wind Energy); Avallone, F. (Polytechnic University of Turin); Sinnige, T. (TU Delft Flight Performance and Propulsion)","","2024","Using propellers in negative thrust conditions can potentially result in many benefits, such as a steeper descent, a reduced landing run, reduced community noise, energy regeneration, etc. However, the aerodynamics and aeroacoustics of propellers in this regime are not well understood. This paper presents an aeroacoustic analysis of an isolated propeller operating in both positive and negative thrust conditions, using scale-resolved lattice-Boltzmann very large eddy simulations and the Ffowcs Williams & Hawkings analogy. The propeller was operated at a constant tip Mach number so that any differences in tonal noise between positive and negative thrust conditions were due to changes in blade loading. Results showed that the flow separation around the blades in the negative thrust case led to a 2 to 6 times higher standard deviation in integrated thrust compared to the positive thrust case. The blade loading in the negative thrust case shows the amplitude of fluctuations up to 18% for inboard sections and up to 30% near the blade tip compared to the time-averaged loads. The noise in the propeller plane is 10 dB higher in the positive thrust regime than in the negative thrust regime at a given absolute thrust level of |T_C = 0.08|. The lower noise at negative thrust is caused by two factors: the lower magnitude of the negative torque compared to the positive torque at a given thrust level and the shift of the blade loading inboard in the negative thrust condition due to the stall of the blade tip. Along the propeller axis, the negative thrust regime has 13-15 dB higher noise because of the increased broadband noise generated by the flow separation. In the negative thrust case, the noise along the propeller axis (89 dB) and propeller plane (92 dB) are comparable. However, this is not the case for the propulsive case. The comparison of noise in the vicinity of the propeller plane showed that using the propellers in negative thrust conditions allows for a steeper and quieter descent compared to a conventional descent; as long as the magnitude of the negative torque produced is equal to or less than the torque required to operate the propeller in a conventional landing.","Propeller aerodynamics; Propeller noise; Regenerative propellers","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:a1503b71-0838-44db-a6e6-0ed694483fcb","http://resolver.tudelft.nl/uuid:a1503b71-0838-44db-a6e6-0ed694483fcb","Dynamic coherence scanning interferometry based on an optical phase mask for simultaneous measurement of local induced vibration and local topology change of a mirror","Vilaboa Pérez, Jesús (Université de Liège); Georges, Marc (Université de Liège); Hastanin, Juriy (Université de Liège); Loicq, J.J.D. (TU Delft Spaceborne Instrumentation; Université de Liège)","","2024","We describe the state of the development of a coherence scanning interferometer to measure local changes in topology and local induced vibrations of a mirror at cryogenic temperatures. The metrology instrument incorporates an optical phase mask and a microlenses array, enabling the acquisition of complete white light interferograms within a single-camera frame. This stands in contrast to traditional temporal phase-shifting interferometers. We design the optical phase mask as a combination of steps of different thicknesses, so each step introduces a different optical path difference to the rays. The local interferograms for each camera frame provide us with information on the local topology of the mirror. The interferogram displacement between camera frames allows us to monitor the mirror’s local induced vibrations. In this work, we report the metrology instrument’s working principle through numerical simulations and present the latest results of a proof of concept developed at the laboratory. The metrology instrument shown is of extensive usability in diverse applications related to real-time measurements of various fast physical processes and real-time characterization of the optical components topology.","coherence scanning interferometry; dynamical interferometry; optical phase mask; single-frame low-coherence interferometry; topology characterization; induced vibrations characterization","en","journal article","","","","","","","","","","","Spaceborne Instrumentation","","",""
"uuid:ea56f881-8f7d-429b-adea-62735ff28326","http://resolver.tudelft.nl/uuid:ea56f881-8f7d-429b-adea-62735ff28326","Connecting the PhD in Design: How PhDs label their Thesis Research","Mattioli, F. (Politecnico di Milano); Figoli, Fabio (Politecnico di Milano); Stappers, P.J. (TU Delft Design Conceptualization and Communication)","Jones, D. (editor); Borekci, N. (editor); Clemente, V. (editor); Corazzo, J. (editor); Lotz, N. (editor); Nielsen, L.M. (editor); Noel, L. (editor)","2024","As design research matures, more designers pursue a PhD. In its turn, the PhD itself is changing from a solitary preparation for a career in academia toward an increasing emphasis on interdisciplinary and international experience and a greater variety of jobs. These developments call for greater opportunities for PhD candidates to build their network during the PhD. The WunderLibrary, developed in the EU-funded project DoCS4Design, aims to connect PhD candidates through a web-based platform for sharing educational and research materials and making contact. To seed the platform's ontology, the collection of tags which connect the items in it, we studied the keywords and metadata from a set of 342 PhD theses from the 6 PhD programmes in the project over the last decade. The collection of theses came with between three and six freely chosen keywords, typically provided by the authors. In this paper, we describe the process of curating the keywords and clustering the resulting data on three levels. This produced a set of 342 keywords and two levels of clustering. The raw data are openly available. We discuss data analysis and a spin-off application that uses higher-level labels to help PhD candidates describe their work.","doctoral education; design research; Keywords; alignment;; research through design","en","conference paper","Design Research Society","","","","","","","","","","Design Conceptualization and Communication","","",""
"uuid:c8a783ba-9619-4a2a-b0f5-c8e4ab5d12ae","http://resolver.tudelft.nl/uuid:c8a783ba-9619-4a2a-b0f5-c8e4ab5d12ae","Towards strengthening Methods in Design Education and Practice","Frascara, Jorge (University of Alberta); Gardien, Paul (Eindhoven University of Technology); Noël, Guillermina (Luzern University of Applied Sciences and Arts); Rosenberg, Daniel (San José State University); Stappers, P.J. (TU Delft Design Conceptualization and Communication); Wilde, Danielle (University of Southern Denmark)","Jones, D. (editor); Borekci, N. (editor); Clemente, V. (editor); Corazzo, J. (editor); Lotz, N. (editor); Nielsen, L.M. (editor); Noel, L. (editor)","2024","Design skills and methods have been at the conceptual foundation of the design discipline(s) for at least the past half century. Over this period, design has also changed, focusing on new outcomes, serving new goals, and addressing different scales and broader application areas. On the one hand, there is a large set of methods and tools; on the other hand, there is growing visibility with ‘design thinking’ both giving design greater appeal and a shallower message. Currently many design schools struggle with adapting their curricula to meet the new demands for sustainability, diversity, and incorporating new technologies such as AI or Biodesign (designing as, with and for nature). Several academic initiatives have produced visions giving direction to those efforts. This paper reports the outcomes of a series of discussions by experienced educators, attempting to produce a specification of the goals and detailed objectives of design methods education. We share these outcomes not as a definitive prescription for the incorporation of methods within a design curriculum, but as a reference point for further development.","design methods; design education; curriculum development; critical thinking","en","conference paper","Design Research Society","","","","","","","","","","Design Conceptualization and Communication","","",""
"uuid:502f6dd5-c64f-4411-ad5a-47f7b0de3db5","http://resolver.tudelft.nl/uuid:502f6dd5-c64f-4411-ad5a-47f7b0de3db5","Photochemical fate of quaternary ammonium compounds (QACs) and degradation pathways predication through computational analysis","Mohapatra, Sanjeeb (TU Delft Sanitary Engineering; National University of Singapore; Campus for Research Excellence and Technological Enterprise); Li Xian, Jovina Lew (National University of Singapore); Gálvez-Rodríguez, Andy (University of Alberta); Ekande, Onkar Sudhir (Indian Institute of Technology Madras); Drewes, Jörg E. (Technische Universität München); Gin, Karina Yew-Hoong (National University of Singapore; Campus for Research Excellence and Technological Enterprise)","","2024","Quaternary ammonium compounds (QACs) are commonly used in many products, such as disinfectants, detergents and personal care products. However, their widespread use has led to their ubiquitous presence in the environment, posing a potential risk to human and environmental health. Several methods, including direct and indirect photodegradation, have been explored to remove QACs such as benzylalkyldimethyl ammonium compounds (BACs) and alkyltrimethyl ammonium compounds (ATMACs) from the environment. Hence, in this research, a systematic review of the literature was conducted using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) method to understand the fate of these QACs during direct and indirect photodegradation in UV/H2O2, UV/PS, UV/PS/Cu2+, UV/chlorine, VUV/UV/chlorine, O3/UV and UV/O3/TiO2 systems which produce highly reactive radicals that rapidly react with the QACs, leading to their degradation. As a result of photodegradation, several transformation products (TPs) of QACs are formed, which can pose a greater risk to the environment and human health than the parent QACs. Only limited research in this area has been conducted with fewer QACs. Hence, quantum mechanical calculations such as density functional theory (DFT)-based computational calculations using Gaussian09 software package were used here to explain better the photo-resistant nature of a specific type of QACs, such as BACs C12-18 and ATMACs C12-C18, and their transformation pathways, providing insights into active sites participating in the phototransformation. Recognizing that different advanced oxidation processes (AOPs) come with pros and cons in the elimination of QACs, this review also highlighted the importance of implementing each AOP concerning the formation of toxic transformation products and electrical energy per order (EEO), especially when QACs coexist with other emerging contaminants (ECs).","Quaternary ammonium compounds (QACs); photochemical fate; computational analysis; degradation pathway","en","review","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:2d975386-a16a-4f4c-bb4e-e93fe38272db","http://resolver.tudelft.nl/uuid:2d975386-a16a-4f4c-bb4e-e93fe38272db","Building Understanding of Experience Design in Digital Health: Preliminary Results Based on Semi-Structured Interviews","Wang, T. (TU Delft Applied Ergonomics and Design); Qian, S. (TU Delft Responsible Marketing and Consumer Behavior); Zhu, Haiou (Loughborough University); Goossens, R.H.M. (TU Delft Human-Centered Design; TU Delft Applied Ergonomics and Design); Giunti, Guido (University of Oulu; Trinity College Dublin); Melles, M. (TU Delft Applied Ergonomics and Design)","Melles, Marijke (editor)","2024","Design is expanding its influence on shaping future healthcare. Ideally, designers apply human-centered design and human factors that introduce theory, principles, and methods to design to optimize people’s healthcare experiences in both digital and non-digital environments. To discuss and implement experience design in healthcare, consensus about experience design in healthcare is needed. Objectives: Therefore, the purpose of this study is to investigate designers’ views on experience design in health, and to uncover their understanding about three experience design concepts, i.e., user experience (UX), patient experience (PEx), and digital patient experience (dPEx). We conducted online semi-structured interviews study with convenience samples who met the eligibility. We used ATLAS.ti for an in-depth data coding following thematic analysis. 24 international designers of digital health solutions, either in industry or in academia took part in the interviews. We found the similarities and differences mentioned between healthcare design and non-healthcare design relate to (1) design principles, (2) user attributes, and (3) design contexts. Furthermore, the differences between UX, PEx, and dPEx can be mapped on five dimensions: people, contexts, purposes, means, and usage scenarios. These insights can help designers and human factors specialists build a common design language for experience design in healthcare. Our study can also assist designers and human factors specialists with experience design in digital health by pointing out the areas where design thinking generally is appropriate and the places where particular expertise in healthcare design is needed.","Digital patient experience; Healthcare design; Human computer interaction; Human-centered design; Patient experience; User experience","en","book chapter","Springer Nature","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-05","","Human-Centered Design","Applied Ergonomics and Design","","",""
"uuid:5e556b73-032c-42a1-b0e3-02f7f8feaaf5","http://resolver.tudelft.nl/uuid:5e556b73-032c-42a1-b0e3-02f7f8feaaf5","The Spatial and Governance Dilemma of Small and Medium-Sized Italian Ports (SMPs): Maritime Spatial Planning (MSP) as a Potential Response","Carella, Fabio (University IUAV of Venice); De Martino, P. (TU Delft History, Form & Aesthetics; University IUAV of Venice); Soffietti, Folco (University IUAV of Venice); Negretto, Vittore (University IUAV of Venice); Musco, Francesco (University IUAV of Venice)","","2024","The Italian coast has about 700 ports, which are different in typology, dimension, role, and ownership. Historically, this has led to the significant fragmentation of governance and space and a lack of cooperation that ports and cities still experience today. Among all ports, small and medium-sized ports (SMPs), such as marinas, small touristic harbors, and moorings, are the most affected. Unlike the main ports, where spatial and strategic regulation planning fall under the port authority’s responsibilities, SMPs are a combination of public and private management and are, therefore, excluded from national and regional planning and larger strategies. Improving SMPs’ cooperation at the regional level can drive more effective sustainable management among related activities (tourism and the fishing sector) and reduce pressures on the land–sea interaction (LSI). In filling the gaps, this article challenges the existing legal framework, planning tools, approaches, and initiatives and may pave the way to establishing a better-integrated national governance for SMPs. In conclusion, this paper identifies two main opportunities that can support the steady establishment of governance and the systematic harmonized development of these SMPs. The first one is offered by maritime spatial planning (MSP) as a strategic and legal tool whereby SMPs are recognized and, if financially supported, could find incentives and measures for their development. The second one is through European projects, programs, and initiatives such as Framesport as drivers in establishing a common ground among public and private interests and as a cooperation engine at a local scale.","common-ground strategy; governance; land–sea interaction; maritime spatial planning; small and medium-sized ports","en","journal article","","","","","","","","","","","History, Form & Aesthetics","","",""
"uuid:273e0093-9c61-4977-99ad-6f3233d17175","http://resolver.tudelft.nl/uuid:273e0093-9c61-4977-99ad-6f3233d17175","Naples: A city away from water: The role of path dependence in the history of Naples","De Martino, P. (TU Delft History, Form & Aesthetics; University IUAV of Venice)","","2024","Over time, a large number of stakeholders have affected the Italian port city of Naples. The millenary history of Naples reveals a port that has been strongly intertwined with the city. Yet, recent history shows a different story. The historical investigation analysed in this article points out a conflict between several different authorities that led the port. As these developed into separate entities they detached people from the water. This article offers an institutional history. Using the concept of path dependence it argues that a past system of decision-making concerning the development of the port city reinforced the separation of land from water in Naples. Path dependence is understood as a resistance by institutions (rules) and actors (decision makers) to changes in patterns of behaviour and a tendency to repeat previous decisions and practices. This article analyses a series of critical junctures so as to analyse the constellation of actors and decisions which have prevented the city from living with water. The article concludes by arguing that understanding the articulated system of past decision-making is a key to (re)conceptualizing the current state of the city and (re)imagining ways by which the city might be reunited with its waters.","historical institutionalism; Naples; path dependence; Port city; water","en","journal article","","","","","","","","","","","History, Form & Aesthetics","","",""
"uuid:d5811855-0b1b-4a3a-a6ea-b0a0a0abd3b5","http://resolver.tudelft.nl/uuid:d5811855-0b1b-4a3a-a6ea-b0a0a0abd3b5","Trained innate immunity modulates osteoblast and osteoclast differentiation","Rahmani, N. R. (University Medical Center Utrecht; Universiteit Utrecht); Belluomo, R. (Universiteit Utrecht); Kruyt, M. C. (University Medical Center Utrecht; University of Twente); Gawlitta, D. (Universiteit Utrecht; University Medical Center Utrecht); Joosten, L. A.B. (Radboud University Medical Center; University of Medicine and Pharmacy); Weinans, Harrie (TU Delft Biomaterials & Tissue Biomechanics; University Medical Center Utrecht); Croes, M. (University Medical Center Utrecht)","","2024","Macrophages are key regulators in bone repair and regeneration. Recent studies have shown that long-term epigenetic changes and metabolic shifts occur during specific immune training of macrophages that affect their functional state, resulting in heightened (trained) or reduced (tolerant) responses upon exposure to a second stimulus. This is known as innate immune memory. Here, we study the impact of macrophages’ memory trait on osteoblast differentiation of human mesenchymal stromal cells (hMSCs) and osteoclast differentiation. An in vitro trained immunity protocol of monocyte-derived macrophages was employed using inactivated Candida albicans and Bacillus Calmette–Guérin (BCG) to induce a ‘trained’ state and Pam3CSK4 (PAM) and Lipopolysaccharides (LPS) to induce a ‘tolerance’ state. Macrophages were subsequently cocultured with hMSCs undergoing osteogenic differentiation during either resting (unstimulated) or inflammatory conditions (restimulated with LPS). Alkaline phosphatase activity, mineralization, and cytokine levels (TNF, IL-6, oncostatin M and SDF-1α) were measured. In addition, macrophages underwent osteoclast differentiation. Our findings show that trained and tolerized macrophages induced opposing results. Under resting conditions, BCG-trained macrophages enhanced ALP levels (threefold), while under inflammatory conditions this was found in the LPS-tolerized macrophages (fourfold). Coculture of hMSCs with trained macrophages showed mineralization while tolerized macrophages inhibited the process under both resting and inflammatory conditions. While osteoclast differentiation was not affected in trained-macrophages, this ability was significantly loss in tolerized ones. This study further confirms the intricate cross talk between immune cells and bone cells, highlighting the need to consider this interaction in the development of personalized approaches for bone regenerative medicine. Graphical Abstract: (Figure presented.).","Bone regeneration; Innate immune memory; Macrophage; MSC; Osteoimmunology","en","journal article","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:a0e4e2b5-a47a-4c51-a0cd-9492131d2d34","http://resolver.tudelft.nl/uuid:a0e4e2b5-a47a-4c51-a0cd-9492131d2d34","Integrated multi-proxy source-to-sink analysis of Late Barremian (Lower Cretaceous) clastic systems in the Essaouira-Agadir Basin","Roquette, Emmanuel (The University of Manchester); Lovell-Kennedy, James (The University of Manchester); Muniz Pichel, Leonardo (The University of Manchester); Schröder, Stefan (The University of Manchester); Charton, R.J.G. (TU Delft Applied Geology; The University of Manchester); Millar, Ian (British Geological Survey); Frau, Camille (The University of Manchester; Groupement d’Intérêt Paléontologique Science et Exposition); Redfern, Jonathan (The University of Manchester)","","2024","This study investigates the provenance of the continental and marine Late Barremian clastics of the Bouzergoun Formation, exposed in the Essaouira-Agadir Basin (EAB). Thin section petrography, Scanning Electron Micrography, heavy minerals analysis, and detrital zircon dating were conducted and integrated with a large dataset of published Low-Temperature Thermochronology (LTT) studies to reconstruct the associated source-to-sink system(s). The results constrain the source and size of the system, and composition of deposited clastics, and investigate the mechanism for delivery of coarse clastics into the offshore domain, a key target for hydrocarbon exploration. The homogeneity of rock composition fingerprints throughout the basin indicates a common provenance for both the northern and southern studied transects. Hinterland analysis based on LTT data identifies the Western Meseta and Massif Ancien de Marrakech (MAM) regions as the only possible source candidates exhuming during the Late Barremian, confirmed by detrital zircon geochronology. Heavy mineral populations reveal partly recycled sediment including a probable igneous source. Rock fragment populations comprise limestones, sandstones, and volcanic composition, which correlate with lithologies of the MAM. The integration of all data suggests a best-fit model for the Late Barremian of a source-to-sink system of moderate size (200–300 km long), dominantly sourced from the MAM (western High Atlas). This provided a sand-rich mix of sediment resulting from the erosion of exhuming Triassic continental basins, with associated clays from the weathering of basalts and Triassic/Jurassic mudstones. Late Barremian eustatic sea level fall, together with regional uplift in the hinterland, is interpreted to have resulted in a forced regression that allowed the system to prograde towards the slope margin, offering enhanced potential for sand delivery into the deep offshore domain. Seismic imaging offshore provides tentative interpretation of synchronous high reflectivity deepwater channels located in structural lows controlled by diapiric salt movement. The Mesetian domain was likely undergoing denudation at the same time and shedding clastic-rich sediments to the northern part of the EAB, beyond the studied region. Sediment supply from the MAM may be mixed with the Mesetian sands to the northern part of the EAB and tentatively in the offshore Essaouira.","Barremian; Bouzergoun formation; Detrital zircon geochronology; Essaouira agadir basin; Hinterland evolution; Low-temperature thermochronology; Lower cretaceous; Morocco; Paleogeology modelling; Provenance; Provenance analysis; Source-to-sink","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:c7d4800d-b7e3-41ce-97c4-f0316e92a48f","http://resolver.tudelft.nl/uuid:c7d4800d-b7e3-41ce-97c4-f0316e92a48f","Effects of thermal shocks on integrity of existing and newly-designed sealants for CCS applications","Li, K. (TU Delft Applied Geophysics and Petrophysics); Pluymakers, Anne (TU Delft Applied Geophysics and Petrophysics)","","2024","Sealants that can guarantee long-term wellbore sealing integrity are of great significance to the safe and sustainable storage of CO2 in carbon capture and storage (CCS). In this study, we investigate how abrupt cyclic thermal shocks affect the integrity of four sealants of different compositions. These sealants include two reference OPC-based blends (S1 and S2), one newly-designed OPC-based blend that contains CO2-sequestering additives (S3), and one calcium aluminate cement (CAC)-based blend designed for CCS applications (S4). We have measured the thermal properties of these samples, followed by quenching and flow-through experiments to apply strong cyclic thermal shocks on samples of the four sealants, where we heated the samples to 120 °C, and quenched them in, or flowed through water of 20 °C. Using X-ray tomography (32 µm/voxel) before and after the experiment showed that both S1, S2 (reference OPC-based) and S4 (CAC-based) broke after thermal-shocking experiments. Cracks and new voids developed in the samples. Post-treatment strength testing shows that thermal shocks reduce the unconfined compressive strength of these three sealants. This implies that these compositions may not be optimal materials for long-term wellbore sealing during CO2 injection and storage afterward. For all these three sealant compositions, quenching resulted in a greater reduction in strength (by 53 % on average) than flow-through experiments (by 29 % on average). On the contrary, we have not observed any cracks after either quenching or flow-through experiments in S3 sealant (OPC with CO2-sequestering additives). We attribute the intactness of this sealant after thermal shocks to its higher thermal diffusivity than the other three sealants. Heat transfers more rapidly in this sealant and the associated thermal stresses are mild and insufficient to cause any damage to its integrity, which makes this sealant a good candidate for wellbore sealing material that can effectively withstand strong thermal shocks encountered during CCS, though further studies are required.","CCS; Sealants; Thermal shocks; Thermally-induced cracking; Well integrity","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:64ae1a0e-9e13-4ba9-a2ed-b61eafce12c6","http://resolver.tudelft.nl/uuid:64ae1a0e-9e13-4ba9-a2ed-b61eafce12c6","Identification of Atrial Transmural Conduction Inhomogeneity Using Unipolar Electrogram Morphology","Zhang, Lu (Erasmus MC); van Schie, M.S. (Erasmus MC); Xiang, Hongxian (Erasmus MC); Liao, Rongheng (Erasmus MC); Zheng, Jiahao (Erasmus MC); Knops, Paul (Erasmus MC); Taverne, Yannick J.H.J. (Erasmus MC); de Groot, N.M.S. (TU Delft Signal Processing Systems; Erasmus MC)","","2024","(1) Background: Structural remodeling plays an important role in the pathophysiology of atrial fibrillation (AF). It is likely that structural remodeling occurs transmurally, giving rise to electrical endo-epicardial asynchrony (EEA). Recent studies have suggested that areas of EEA may be suitable targets for ablation therapy of AF. We hypothesized that the degree of EEA is more pronounced in areas of transmural conduction block (T-CB) than single-sided CB (SS-CB). This study examined the degree to which SS-CB and T-CB enhance EEA and which specific unipolar potential morphology parameters are predictive for SS-CB or T-CB. (2) Methods: Simultaneous endo-epicardial mapping in the human right atrium was performed in 86 patients. Potential morphology parameters included unipolar potential voltages, low-voltage areas, potential complexity (long double and fractionated potentials: LDPs and FPs), and the duration of fractionation. (3) Results: EEA was mostly affected by the presence of T-CB areas. Lower potential voltages and more LDPs and FPs were observed in T-CB areas compared to SS-CB areas. (4) Conclusion: Areas of T-CB could be most accurately predicted by combining epicardial unipolar potential morphology parameters, including voltages, fractionation, and fractionation duration (AUC = 0.91). If transmural areas of CB indeed play a pivotal role in the pathophysiology of AF, they could theoretically be used as target sites for ablation.","electrograms; endo-epicardial delay; simultaneous endo-epicardial mapping; sinus rhythm; transmural conduction block","en","journal article","","","","","","","","","","","Signal Processing Systems","","",""
"uuid:f466d058-abc3-4d3f-b916-61ad5afc8b2e","http://resolver.tudelft.nl/uuid:f466d058-abc3-4d3f-b916-61ad5afc8b2e","Fatigue behaviour of root crack in stiffener-to-deck plate weld at crossbeam of orthotropic bridge decks","Wu, W. (TU Delft Steel & Composite Structures); Veljkovic, M. (TU Delft Steel & Composite Structures); Kolstein, M.H. (TU Delft Steel & Composite Structures); Pijpers, Richard (TNO); Maljaars, Johan (Eindhoven University of Technology; TNO)","","2024","Steel Orthotropic Bridge Decks (OBDs) are widely used in long-span and movable bridges. Fatigue resistance analysis plays an important role in the design or assessment of OBDs. One possible fatigue failure is the crack initiating from the weld root of stiffener-to-deck plate connections at crossbeams. A full-scale experimental investigation in this study using a 20 mm thick deck plate with a dimension of 9.4 m × 5.1 m, including three crossbeams, represents the modern designed OBDs. The experiments show an arrest of crack propagation with a final crack depth of approximately 75% of the deck plate thickness. On the contrary, through thickness cracks develop in deck plates of 10 or 12 mm. Hot spot stress based fatigue detail categories (DC) using various failure criteria derived from the tests. Analysis with the effective notch stress shows that the DC has low sensitivity to the amount of weld penetration. The results of analyses with the eXtended Finite Element Method (XFEM), employed to analyse the fatigue crack propagation path and crack arrest, are in line with the experimental study.","Crack arrest; Fatigue resistance; Hot spot stress; Orthotropic bridge deck; Stiffener-to-deck plate weld at crossbeam","en","journal article","","","","","","","","","","","Steel & Composite Structures","","",""
"uuid:cf3f497d-32d5-4c84-aeb0-404314965385","http://resolver.tudelft.nl/uuid:cf3f497d-32d5-4c84-aeb0-404314965385","Predicting protein retention in ion-exchange chromatography using an open source QSPR workflow","Neijenhuis, T. (TU Delft BT/Bioprocess Engineering); Le Bussy, Olivier (GSK Vaccines, Rixensart); Geldhof, Geoffroy (GSK Vaccines, Rixensart); Klijn, M.E. (TU Delft BT/Bioprocess Engineering); Ottens, M. (TU Delft BT/Design and Engineering Education)","","2024","Protein-based biopharmaceuticals require high purity before final formulation to ensure product safety, making process development time consuming. Implementation of computational approaches at the initial stages of process development offers a significant reduction in development efforts. By preselecting process conditions, experimental screening can be limited to only a subset. One such computational selection approach is the application of Quantitative Structure Property Relationship (QSPR) models that describe the properties exploited during purification. This work presents a novel open-source Python tool capable of extracting a range of features from protein 3D models on a local computer allowing total transparency of the calculations. As open-source tool, it also impacts initial investments in constructing a QSPR workflow for protein property prediction for third parties, making it widely applicable within the field of bioprocess development. The focus of current calculated molecular features is projection onto the protein surface by constructing surface grid representations. Linear regression models were trained with the calculated features to predict chromatographic retention times/volumes. Model validation shows a high accuracy for anion and cation exchange chromatography data (cross-validated R2 of 0.87 and 0.95). Hence, these models demonstrate the potential of the use of QSPR to accelerate process design.","chromatography; protein features; Quantitative Structure Activity Relationship (QSAR); Quantitative Structure Property Relationship (QSPR); retention prediction","en","journal article","","","","","","","","","","","BT/Bioprocess Engineering","","",""
"uuid:ab0d528e-a03c-4e14-8df1-538a959afb96","http://resolver.tudelft.nl/uuid:ab0d528e-a03c-4e14-8df1-538a959afb96","Experimental characterization of damage during geothermal production of hot dry rocks: Comprehensive effects of the damage-elastic deformation on conductivity evolution","Xu, Fuqiang (China University of Petroleum - Beijing); Shi, Yu (Southwest Jiaotong University); Song, Xianzhi (China University of Petroleum - Beijing); Wu, Wei (Nanyang Technological University); Song, G. (TU Delft Applied Geology); Li, Shuang (China University of Petroleum - Beijing)","","2024","The development of hot dry rocks (HDRs) is of great significance to adjusting energy structure, alleviating energy shortage, reducing pollution, etc. Low-permeability granite is the predominant rock type in deep HDRs, making fractures the primary pathways for fluid circulation and heat extraction. The production of HDRs is significantly influenced by variable fracture conductivity, but current conductivity characterization primarily relies on the elastic deformation of the matrix, neglecting the impact of damage. Accordingly, we propose an experimental method and a supporting apparatus, which is used to unveil the conductivity evolution characteristics resulting from the comprehensive effects of damage and elastic deformation. The experimental results demonstrate that when subjected to confining force squeezing inward, the fracture conductivity experiences varying degrees of decrease compared to its initial state before the experiment. By utilizing the conductivity evolution rate as the evaluation criterion and conducting grey correlation analysis, it has been determined that temperature exerts the most significant influence on the conductivity evolution, followed by injection flow, and lastly, confining pressure. Moreover, rock particle types and production cycles also have different degrees of effect. After considering the comprehensive effects of damage-elastic deformation at the field-scale, the damage has a positive effect on conductivity enhancement. Our study provides a new approach for the characterization of fracture conductivity evolution for deep geothermal projects.","Comprehensive effects; Conductivity evolution; Elastic deformation; Fracture damage; Hot dry rocks; Injection experiment","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-07","","","Applied Geology","","",""
"uuid:2de10f3f-ef0e-495c-8b2c-3129d9ee35c4","http://resolver.tudelft.nl/uuid:2de10f3f-ef0e-495c-8b2c-3129d9ee35c4","Effect of temperature on dislocation-tuned dielectricity and piezoelectricity in single-crystal BaTiO3","Dietrich, Felix (Technische Universität Darmstadt); Ni, Fan (Technische Universität Darmstadt); Fulanović, Lovro (Technische Universität Darmstadt); Zhou, Xiandong (Sichuan University); Isaia, Daniel (Technische Universität Darmstadt); Braga Groszewicz, P. (TU Delft RST/Storage of Electrochemical Energy); Zhang, Chunlin (Physcience Optoelectronics Co., Ltd, Beijing); Xu, Bai Xiang (Technische Universität Darmstadt); Rödel, Jürgen (Technische Universität Darmstadt)","","2024","The pinning-controlled mobility of ferroelectric/ferroelastic domain walls is an important part of managing polarization switching and determining the final properties of ferroelectric and piezoelectric materials. Here, we assess the impact of temperature on dislocation-induced domain wall pinning as well as on dislocation-tuned dielectric and piezoelectric response in barium titanate single crystals. Our solid-state nuclear magnetic resonance spectroscopy results indicate that the entire sample exclusively permits in-plane domains, with their distribution remaining insensitive to temperature changes below the Curie temperature (TC). The domain wall pinning field monotonically decreases with increasing temperature up to TC, as evidenced by a combination of experimental observations and phase-field simulations. Our work highlights the promising potential of dislocation engineering in controlling domain wall mobility within bulk ferroelectrics.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-11","","","RST/Storage of Electrochemical Energy","","",""
"uuid:d61a6e0a-cc06-486b-a78d-dad20e686e53","http://resolver.tudelft.nl/uuid:d61a6e0a-cc06-486b-a78d-dad20e686e53","Accelerating Large-Scale Graph Processing with FPGAs: Lesson Learned and Future Directions","Procaccini, Marco (University of Siena); Sahebi, Amin (University of Siena); Barbone, Marco (Imperial College London); Luk, Wayne (Imperial College London); Gaydadjiev, G. (TU Delft Quantum Circuit Architectures and Technology); Giorgi, Roberto (University of Siena)","Bispo, Joao (editor); Xydis, Sotirios (editor); Curzel, Serena (editor); Sousa, Luis Miguel (editor)","2024","Processing graphs on a large scale presents a range of difficulties, including irregular memory access patterns, device memory limitations, and the need for effective partitioning in distributed systems, all of which can lead to performance problems on traditional architectures such as CPUs and GPUs. To address these challenges, recent research emphasizes the use of Field-Programmable Gate Arrays (FPGAs) within distributed frameworks, harnessing the power of FPGAs in a distributed environment for accelerated graph processing. This paper examines the effectiveness of a multi-FPGA distributed architecture in combination with a partitioning system to improve data locality and reduce inter-partition communication. Utilizing Hadoop at a higher level, the framework maps the graph to the hardware, efficiently distributing pre-processed data to FPGAs. The FPGA processing engine, integrated into a cluster framework, optimizes data transfers, using offline partitioning for large-scale graph distribution. A first evaluation of the framework is based on the popular PageRank algorithm, which assigns a value to each node in a graph based on its importance. In the realm of large-scale graphs, the single FPGA solution outperformed the GPU solution that were restricted by memory capacity and surpassing CPU speedup by 26x compared to 12x. Moreover, when a single FPGA device was limited due to the size of the graph, our performance model showed that a distributed system with multiple FPGAs could increase performance by around 12x. This highlights the effectiveness of our solution for handling large datasets that surpass on-chip memory restrictions.","Accelerators; Distributed computing; FPGA; Graph processing; Grid partitioning","en","conference paper","Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing","","","","","","","","","","Quantum Circuit Architectures and Technology","","",""
"uuid:72bb8f0a-579b-4454-ac27-dfd86c544bef","http://resolver.tudelft.nl/uuid:72bb8f0a-579b-4454-ac27-dfd86c544bef","Photoimmuno-antimicrobial therapy for Staphylococcus aureus implant infection","van Dijk, Bruce (University Medical Center Utrecht); Oliveira, Sabrina (Universiteit Utrecht); Hooning van Duyvenbode, J. Fred F. (University Medical Center Utrecht); Nurmohamed, F. Ruben H.A. (University Medical Center Utrecht); Mashayekhi, Vida (Universiteit Utrecht); Beltran Hernandez, Irati (Universiteit Utrecht); van Strijp, Jos (University Medical Center Utrecht); de Vor, Lisanne (University Medical Center Utrecht); Aerts, Piet C. (University Medical Center Utrecht); Vogely, H. Charles (University Medical Center Utrecht); Weinans, Harrie (TU Delft Biomaterials & Tissue Biomechanics; University Medical Center Utrecht); van der Wal, Bart C.H. (University Medical Center Utrecht)","","2024","Introduction Implant infections caused by Staphylococcus aureus are responsible for high mortality and morbidity worldwide. Treatment of these infections can be difficult especially when bacterial biofilms are involved. In this study we investigate the potential of infrared photoimmunotherapy to eradicate staphylococcal infection in a mouse model. Methods A monoclonal antibody that targets Wall Teichoic Acid surface components of both S. aureus and its biofilm (4497-IgG1) was conjugated to a photosensitizer (IRDye700DX) and used as photoimmunotherapy in vitro and in vivo in mice with a subcutaneous implant pre-colonized with biofilm of Staphylococcus aureus. A dose of 400 μg and 200 μg of antibody-photosensitizer conjugate 4497-IgG–IRDye700DXwas administered intravenously to two groups of 5 mice. In addition, multiple control groups (vancomycin treated, unconjugated IRDye700DX and IRDye700DX conjugated to a non-specific antibody) were used to verify anti-microbial effects. Results In vitro results of 4497-IgG-IRDye700DX on pre-colonized (biofilm) implants showed significant (p<0.01) colony-forming units (CFU) reduction at a concentration of 5 μg of the antibody-photosensitizer conjugate. In vivo, treatment with 4497-IgG-IRDye700DX showed no significant CFU reduction at the implant infection. However, tissue around the implant did show a significant CFU reduction with 400 μg 4497-IgG-IRDye700DX compared to control groups (p = 0.037). Conclusion This study demonstrated the antimicrobial potential of photoimmunotherapy for selectively eliminating S. aureus in vivo. However, using a solid implant instead of a catheter could result in an increased bactericidal effect of 4497-IgG-IRDye700DX and administration locally around an implant (per operative) could become valuable applications in patients that are difficult to treat with conventional methods. We conclude that photoimmunotherapy could be a potential additional therapy in the treatment of implant related infections, but requires further improvement.","","en","journal article","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:f733e4e4-9c97-4e7a-969e-b90716ad5a77","http://resolver.tudelft.nl/uuid:f733e4e4-9c97-4e7a-969e-b90716ad5a77","Rijksoverheidsbeleid voor de transformatie naar wonen","Remøy, H.T. (TU Delft Real Estate Management); Heurkens, E.W.T.M. (TU Delft Urban Development Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Sinds 2005 heeft de Rijksoverheid de transformatie van bestaande gebouwen op de agenda staan. In die tijd werd namelijk duidelijk dat de kantorenleegstand was opgelopen tot problematische proporties, en liep tegelijkertijd de woningbouwproductie achter op de beleidsdoelstelling. De productie van woningen door transformatie werd voor het eerst in diverse beleidsnotities onderschreven. Enerzijds om de woningproductie te verhogen, anderzijds om verloedering en leegstand in steden tegen te gaan. Een duurzame transformatie van gebouwen is bovendien een strategie die bijvoorbeeld sociaal-demografische veranderingen opvangt, de economische basis van steden ondersteunt en de stedelijke kwaliteit verbetert. In 2022 werd door minister Hugo de Jonge van Binnenlandse Zaken en Koninkrijksrelaties het doel geformuleerd om jaarlijks 15.000 woningen te realiseren door transformatie (zie ‘1. De markt voor transformatie naar woningen’). Om de doelstellingen te behalen, is ook een hervorming van vastgoedmarkten nodig, waarbij instellingen en organisaties de voorkeur geven aan transformatie boven sloop en nieuwbouw. Dit vereist echter het gebruik van publieke beleidsinstrumenten die aansluiten bij de veranderende eisen van de vastgoedmarkt en de behoeften van marktactoren. Dit hoofdstuk illustreert dat om bestaand vastgoed te transformeren naar woningen een effectieve mix van beleidsinstrumenten en activiteiten vereist is die is afgestemd op de marktbehoeften op zowel stedelijk als lokaal niveau. Achtereenvolgens wordt het overheidsbeleid ten aanzien van de transformatie naar wonen uiteengezet en gecategoriseerd teneinde een beeld te schetsen van de veelheid en mogelijke effectiviteit van dat beleid.","Public policy; Transformation; Housing","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Real Estate Management","","",""
"uuid:3641eacc-24eb-4db7-b3c7-6a20ab1f7840","http://resolver.tudelft.nl/uuid:3641eacc-24eb-4db7-b3c7-6a20ab1f7840","Samenwerking bij gebiedstransformaties naar wonen","Heurkens, E.W.T.M. (TU Delft Urban Development Management)","Remøy, Hilde (editor); van Bortel, Gerard (editor); Heurkens, Erwin (editor); van Venrooij, Roeli (editor)","2024","Gebiedstransformaties hebben als algemeen kenmerk dat bestaande kantoor-, bedrijven-, winkel- of industriegebieden worden getransformeerd naar gebieden waarin de woonfunctie aan aandeel wint. Gebouwtransformaties vinden uiteraard ook plaats binnen zo’n gebiedstransformatie. Op gebiedsniveau vinden er echter vaak (andere) gebouw- en kaveloverstijgende afwegingen plaats die ook van belang kunnen zijn voor het realiseren van gebouwtransformaties naar wonen. Zeer kenmerkend voor deze gebiedstransformaties is het grote aantal uiteenlopende partijen die onderling in meer of mindere mate samenwerken aan de transformatie van een gebied. In dit hoofdstuk behandelen we de betrokken partijen, een specifieke samenwerkingsvorm (‘Developing Apart Together’) en de partnerselectiemethode die van belang zijn voor een effectieve en duurzame samenwerking bij gebiedstransformaties naar wonen.","Transformation; Partnerships; Collaboration","nl","book chapter","Bouwkunde TU Delft","","","","","","","","","","Urban Development Management","","",""
"uuid:33971f54-4b3d-4bee-a23d-217b69bd240a","http://resolver.tudelft.nl/uuid:33971f54-4b3d-4bee-a23d-217b69bd240a","Input Decoupling of Lagrangian Systems via Coordinate Transformation: General Characterization and its Application to Soft Robotics","Pustina, P. (TU Delft Learning & Autonomous Control; Sapienza University of Rome); Della Santina, C. (TU Delft Learning & Autonomous Control; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Boyer, Frederic (IMT Atlantique); De Luca, Alessandro (Sapienza University of Rome); Renda, Federico (Khalifa University of Science and Technology)","","2024","Suitable representations of dynamical systems can simplify their analysis and control. On this line of thought, this paper aims to answer the following question: <italic>Can a transformation of the generalized coordinates under which the actuators directly perform work on a subset of the configuration variables be found?</italic> Not only we show that the answer to this question is <italic>yes</italic>, but we also provide necessary and sufficient conditions. More specifically, we look for a representation of the configuration space such that the right-hand side of the dynamics in Euler-Lagrange form becomes [<italic>IO</italic>]tu, being u the system input. We identify a class of systems, called <italic>collocated</italic>, for which this problem is solvable. Under mild conditions on the input matrix, a simple test is presented to verify whether a system is collocated or not. By exploiting power invariance, we provide necessary and sufficient conditions that a change of coordinates decouples the input channels if and only if the dynamics is collocated. In addition, we use the collocated form to derive novel controllers for damped underactuated mechanical systems. To demonstrate the theoretical findings, we consider several Lagrangian systems with a focus on continuum soft robots.","Dynamics; Mechanical systems; Modeling, Control, and Learning for Soft Robots; Motion Control; Robot kinematics; Robots; Soft robotics; Sufficient conditions; Symmetric matrices; Underactuated Robots; Vectors","en","journal article","","","","","","","","","","","Learning & Autonomous Control","","",""
"uuid:f6f291c6-6725-4114-b9db-f5fe858a1029","http://resolver.tudelft.nl/uuid:f6f291c6-6725-4114-b9db-f5fe858a1029","From Global South to Underrepresented Geographies","Tempels Moreno Pessoa, Igor (University of Twente); van der Watt, A. (TU Delft Real Estate Management); Vergara d'Alençon, L.M. (Universidad Diego Portales); Newton, C.E.L. (TU Delft Spatial Planning and Strategy)","van der Watt, Anja (editor); Vergara, Luz María (editor); Pessoa, Igor (editor); Newton, Caroline (editor)","2024","In light of rapid urbanisation and the accelerating threats of climate change, scale and multitude are what set the Global North and South apart. Yet, as this course exposes, the issues faced by urban areas have resembling themes and characteristics, regardless of economic status or geographic location. Therefore, in the context of sustainable urban development, the binary dichotomy of the terms ‘Global North’ and ‘Global South’ must be contested. While a focus on Africa, Latin America and the Caribbean, Asia, and the MENA region, Rethink the City attempts to understand the transboundary nature of urban issues and provide a platform to gather insights beyond borders. It is only by learning from other narratives that we can collectively address the complex challenges ahead.","Global South; Global North; language; underrepresented geographies; unbalanced; imaginary; perceptions; place-based; decolonise","en","book chapter","TU Delft OPEN","","","","","","","","","","Real Estate Management","","",""
"uuid:62903ec3-c55a-4042-8469-f6c5c64f5a03","http://resolver.tudelft.nl/uuid:62903ec3-c55a-4042-8469-f6c5c64f5a03","Rethink the City: Facts, Global Community and Pressing Urban Challenges.","Vergara d'Alençon, L.M. (Universidad Diego Portales); van der Watt, A. (TU Delft Real Estate Management; TU Delft Spatial Planning and Strategy); Tempels Moreno Pessoa, Igor (University of Twente); Newton, C.E.L. (TU Delft Spatial Planning and Strategy)","van der Watt, Anja (editor); Vergara, Luz María (editor); Pessoa, Igor (editor); Newton, Caroline (editor)","2024","Rethink the City supports the co-production of knowledge through collaborative efforts of the global community. Its ambition to broaden the academic study of urban challenges to underrepresented geographies is reflected in its form: A free, online course inclusive to all, regardless of location or background. However, despite its benefits, online education has evident setbacks. This chapter seeks to shine a light on various issues faced by this unconventional academic curriculum and what kind of measures were taken to overcome them.","Co-creation; co-production; online education; platforms; digital learning; participation","en","book chapter","TU Delft OPEN","","","","","","","","","","Real Estate Management","","",""
"uuid:260ad45b-b04f-468a-aa87-49b289800a62","http://resolver.tudelft.nl/uuid:260ad45b-b04f-468a-aa87-49b289800a62","Acousto-Optical Tuneable Filter design for efficient diffraction of unpolarised light","Dupont, Samuel (Université Polytechnique Hauts de France); Kastelik, Jean-Claude (Université Polytechnique Hauts de France); Vanhamel, J. (TU Delft Space Systems Egineering); Dekemper, Emmanuel (Royal Belgian Institute for Space Aeronomy (BIRA-IASB))","Astolfi, Arianna (editor); Asdrudali, Francesco (editor); Shtrepi, Louena (editor)","2024","Diffraction of optical waves by an acoustic grating is a well-known phenomenon that enables the design of very versatile devices useful in photonic systems. For example, Acousto-Optic Tuneable Filters (AOTFs) can be dynamically tuned by radio-frequency signals. Among possible material choice, tellurium dioxide crystal is often used for practical applications due to its high efficiency. In such a birefringent material, the anisotropic configuration is often used. A feature of this configuration is the sensitivity to optical input polarisation: a selective coupling between polarized modes occurs. The incident must be polarised and
the diffracted mode polarisation is orthogonal to the incident one.
However, during the design process a very specific operation point can be found that ensures the simultaneous diffraction of both the ordinary and the extraordinary optical modes. In this presentation, we introduce the design of AOTF in birefringent crystals and present the main parameters that are subject to trade-off. Acousto-optic diffraction efficiency is sensitive to the so-called phase matching condition between optical wave and the ultrasonic
wave. The offset from synchronicity is considered introducing a phase mismatch parameter. Diffraction efficiency evolution with respect to Bragg condition offset are illustrated. A custom device is finally presented that ensures simultaneous diffraction of both polarisation modes and compared to experimental results.","AOTF; anisotropic diffraction; unpolarised light","en","conference paper","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-01","","","Space Systems Egineering","","",""
"uuid:1729ac19-9537-4131-a48b-4900c63a9a24","http://resolver.tudelft.nl/uuid:1729ac19-9537-4131-a48b-4900c63a9a24","Assessing nozzle flow dynamics in fused filament fabrication through the parametric map α − λ","Schuller, Tomás (Universidade do Porto; Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI)); Fanzio, P. (TU Delft Micro and Nano Engineering); Galindo-Rosales, Francisco J. (Universidade do Porto)","","2024","Polymer rheology profoundly influences the intricate dynamics of material extrusion in fused filament fabrication (FFF). This numerical study, which uses the Giesekus model fed with a full rheometric experimental dataset, meticulously examines the molten flow patterns inside the printing nozzle in FFF. Our findings reveal new insight into the interplay between elastic stresses and complex flow patterns, highlighting their substantial role in forming upstream vortices. The parametric map α-λ from the Giesekus model allowed us to sort the materials and connect the polymer rheology with the FFF nozzle flow dynamics. The identification of elastic instabilities, the characterization of flow types, and the correlation between fluid rheology and pressure drop variations mark significant advancements in understanding FFF processes. These insights pave the way for tailored nozzle designs, promising enhanced efficiency and reliability in FFF-based additive manufacturing.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-11","","","Micro and Nano Engineering","","",""
"uuid:7e632475-60c7-4570-aae1-e258a9cdf3a9","http://resolver.tudelft.nl/uuid:7e632475-60c7-4570-aae1-e258a9cdf3a9","Quantifying riming from airborne data during the HALO-(AC)3campaign","Maherndl, Nina (University of Leipzig); Moser, Manuel (University of Mainz; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Lucke, J.R. (TU Delft Aircraft Noise and Climate Effects; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Mech, Mario (University of Cologne); Risse, Nils (University of Cologne); Schirmacher, Imke (University of Cologne); Maahn, Maximilian (University of Leipzig)","","2024","Riming is a key precipitation formation process in mixed-phase clouds which efficiently converts cloud liquid to ice water. Here, we present two methods to quantify riming of ice particles from airborne observations with the normalized rime mass, which is the ratio of rime mass to the mass of a size-equivalent spherical graupel particle. We use data obtained during the HALO-(AC)3 aircraft campaign, where two aircraft collected radar and in situ measurements that were closely spatially and temporally collocated over the Fram Strait west of Svalbard in spring 2022. The first method is based on an inverse optimal estimation algorithm for the retrieval of the normalized rime mass from a closure between cloud radar and in situ measurements during these collocated flight segments (combined method). The second method relies on in situ observations only, relating the normalized rime mass to optical particle shape measurements (in situ method). We find good agreement between both methods during collocated flight segments with median normalized rime masses of 0.024 and 0.021 (mean values of 0.035 and 0.033) for the combined and in situ method, respectively. Assuming that particles with a normalized rime mass smaller than 0.01 are unrimed, we obtain average rimed fractions of 88ĝ€¯% and 87ĝ€¯% over all collocated flight segments. Although in situ measurement volumes are in the range of a few cubic centimeters and are therefore much smaller than the radar volume (about 45ĝ€¯m footprint diameter at an altitude of 500ĝ€¯m above ground, with a vertical resolution of 5ĝ€¯m), we assume they are representative of the radar volume. When this assumption is not met due to less homogeneous conditions, discrepancies between the two methods result. We show the performance of the methods in a case study of a collocated segment of cold-air outbreak conditions and compare normalized rime mass results with meteorological and cloud parameters. We find that higher normalized rime masses correlate with streaks of higher radar reflectivity. The methods presented improve our ability to quantify riming from aircraft observations.","","en","journal article","","","","","","","","","","","Aircraft Noise and Climate Effects","","",""
"uuid:10b92009-fa98-447a-bec1-5fa706f4d643","http://resolver.tudelft.nl/uuid:10b92009-fa98-447a-bec1-5fa706f4d643","Simulating decadal cross-shore dynamics at nourished coasts with Crocodile","Kettler, T.T. (TU Delft Coastal Engineering); de Schipper, M.A. (TU Delft Coastal Engineering); Luijendijk, Arjen (TU Delft Coastal Engineering; Deltares)","","2024","Projections of high rates of sea level rise have stimulated proposals for adaptation strategies with increasingly high nourishment volumes along sandy beaches. An underlying assumption is that coastal profiles respond rapidly to nourishments by redistributing sediments towards a (new) equilibrium shape. However, this perception may not be valid when high volumes of nourishment are applied, as the profile shape may then undergo significant deformation. Current state-of-the-art modelling techniques often concentrate on a single spatio-temporal scale, either lacking the necessary temporal horizon or failing to provide the required level of cross-shore detail. This article introduces Crocodile, a diffusion based cross-shore model designed to bridge the gap between short- and long-term nourishment modelling. The model simulates the effects of nourishment strategies on coastal volume, coastline position and beach width over a decadal timeframe. It incorporates different elements which compute cross-shore diffusion, sediment exchange with the dune and longshore sediment losses. To test the model performance, a series of idealized nourishment scenarios are examined, along with three case studies along the Dutch coast with different nourishment strategies over the past few decades. The modelled coastal volume, shoreline position and beach width strongly resemble the observations with only a 12% overestimation in profile volume and 13% underestimation in beach width. Averaged over selected periods of nourishment, trends and trend reversals between different strategies are well replicated with slight overestimation for coastal volume trends by 1.5m3/m/yr(10%), while beach width trends are underestimated by 0.2m/yr (15%). Given that the added nourishment volumes are typically in the order of 100m3/m, these model errors are considered sufficiently low to conclude that Crocodile effectively simulates variations in coastal volume, coastline position and beach width over a decadal timeframe in response to different nourishment strategies. Therefore, Crocodile can facilitate the evaluation of future nourishment strategies.","Cross-shore profile; Diffusion model; Nourishment strategies; Numerical modelling; Sand dispersion","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:910e5bb9-6bb1-4306-9d9b-bca5eb95f564","http://resolver.tudelft.nl/uuid:910e5bb9-6bb1-4306-9d9b-bca5eb95f564","Single-crystal vs polycrystalline boron-doped diamond anodes: Comparing degradation efficiencies of carbamazepine in electrochemical water treatment","Feijoo, Sara (Katholieke Universiteit Leuven); Baluchová, S. (TU Delft Micro and Nano Engineering; Charles University); Kamali, Mohammadreza (Katholieke Universiteit Leuven); Buijnsters, J.G. (TU Delft Micro and Nano Engineering); Dewil, Raf (Katholieke Universiteit Leuven; University of Oxford)","","2024","The ongoing challenge of water pollution by contaminants of emerging concern calls for more effective wastewater treatment to prevent harmful side effects to the environment and human health. To this end, this study explored for the first time the implementation of single-crystal boron-doped diamond (BDD) anodes in electrochemical wastewater treatment, which stand out from the conventional polycrystalline BDD morphologies widely reported in the literature. The single-crystal BDD presented a pure diamond (sp3) content, whereas the three other investigated polycrystalline BDD electrodes displayed various properties in terms of boron doping, sp3/sp2 content, microstructure, and roughness. The effects of other process conditions, such as applied current density and anolyte concentration, were simultaneously investigated using carbamazepine (CBZ) as a representative target pollutant. The Taguchi method was applied to elucidate the optimal operating conditions that maximised either (i) the CBZ degradation rate constant (enhanced through hydroxyl radicals (•OH)) or (ii) the proportion of sulfate radicals (SO4•−) with respect to •OH. The results showed that the single-crystal BDD significantly promoted •OH formation but also that the interactions between boron doping, current density and anolyte concentration determined the underlying degradation mechanisms. Therefore, this study demonstrated that characterising the BDD material and understanding its interactions with other process operating conditions prior to degradation experiments is a crucial step to attain the optimisation of any wastewater treatment application.","boron-doped diamond (BDD); Electrochemical advanced oxidation processes (eAOPs); polycrystalline; single-crystal; wastewater treatment","en","journal article","","","","","","","","","","","Micro and Nano Engineering","","",""
"uuid:a11a1f00-5d56-432a-be7d-28cec545e835","http://resolver.tudelft.nl/uuid:a11a1f00-5d56-432a-be7d-28cec545e835","Compliant variable negative to zero to positive stiffness twisting elements","Amoozandeh, A. (TU Delft Mechatronic Systems Design); Herder, J.L. (TU Delft Precision and Microsystems Engineering); Radaelli, G. (TU Delft Mechatronic Systems Design)","","2024","Compliant mechanisms have the potential to be utilized in numerous applications where the use of conventional mechanisms is unfeasible. These mechanisms have inherent stiffness in their range of motion as they gain their mobility from elastic deformations of elements. In most systems, however, complete control over the elasticity is desired. Therefore, compliant mechanisms with variable, including zero, stiffness can have a great advantage. We present a novel concept based on the prestressing of open thin-walled multi-symmetric beams. It is demonstrated that by changing the prestress on the center-axis of these beams, a range of variable torsional stiffness can be achieved. For beams with a large warping constant, the stiffness changes from positive to zero and negative as the prestress increases, while for beams with a near-zero warping constant, the range of neutrally stable twisting motion increases. A planar equivalent is shown in this work to elucidate the notion, and numerical and experimental analyses are performed to validate the prestress-related behavior.","Bistable mechanisms; Compliant mechanisms; Negative stiffness; Twisting beams; Variable stiffness; Zero stiffness","en","journal article","","","","","","","","","","Precision and Microsystems Engineering","Mechatronic Systems Design","","",""
"uuid:3887147a-52d0-4718-99ee-ec595e1cbd9a","http://resolver.tudelft.nl/uuid:3887147a-52d0-4718-99ee-ec595e1cbd9a","On-Demand Magnetically-Activated Drug Delivery from Additively Manufactured Porous Bone Implants to Tackle Antibiotic-Resistant Infections","Salandova, M. (TU Delft Biomaterials & Tissue Biomechanics); Leeflang, M.A. (TU Delft Biomaterials & Tissue Biomechanics); Klimopoulou, M. (TU Delft Biomaterials & Tissue Biomechanics); Fratila-Apachitei, E.L. (TU Delft Biomaterials & Tissue Biomechanics); Apachitei, I. (TU Delft Biomaterials & Tissue Biomechanics); Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics; Leiden University Medical Center)","","2024","This study proposes a new concept for an on-demand drug releasing device intended for integration into additively manufactured (i.e., 3D printed) orthopedic implants. The system comprises a surface with conduits connected to a subsurface reservoir used for storage and on-demand release of antimicrobial agents, covered with a cap that prevents the antibacterial agents from being released until alternating magnetic field (AMF) raises the temperature of the cap, thus, releasing the stored drug. To demonstrate this concept, Ti6Al4V specimens are directly 3D printed using selective laser melting and their surface, reservoirs, and drug releasing properties are characterized. A new synthetic antimicrobial peptide, SAAP-148, is thereafter tested for its cytotoxic, osteogenic, and immunomodulatory effects at concentrations relevant for its minimal bactericidal concentration (MBC) and is compared with its natural analogue, LL-37. The results showed that AMF successfully activated the release from the 3D printed loaded samples. Both peptides demonstrated to be non-cytotoxic within the MBC levels for macrophages and preosteoblasts and did not influence their osteoimmunomodulatory behavior. The findings of this study indicate that the proposed concept is technically feasible and has the potential to be used for the development of bone implants with on-demand delivery systems to fight IAI without systemic or continuous local release of antibiotics.","3D printing; antibiotic-resistance infections; antimicrobial peptides; drug delivery; implant-associated infections; orthopedic implants","en","journal article","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:a878b31c-0ce2-457f-b41c-d67b94ab11ba","http://resolver.tudelft.nl/uuid:a878b31c-0ce2-457f-b41c-d67b94ab11ba","OpenFOAM design sensitivity analysis on a homogeneous low-crested structure with concrete elements seaward of a vertical seawall to reduce overtopping","Jonker, R. G. (Student TU Delft; Aveco de Bondt); AlYousif, A.Y. (TU Delft Hydraulic Structures and Flood Risk; Kuwait University); Hofland, Bas (TU Delft Hydraulic Structures and Flood Risk); Antonini, A. (TU Delft Coastal Engineering); Zoon, Arthur (Van Oord); Smith, Gregory (Van Oord)","","2024","This study treats a detached homogenous low-crested structure (HLCS) made of Cubipod concrete elements placed seaward of a vertical wall (forming a basin in between) to reduce overtopping. Assessing the complex hydrodynamics and effects of changing the geometry of such a system in relation to overtopping reduction is challenging. The numerical model OpenFOAM was applied to this end. Forchheimer coefficients for wave transmission and the flow through the HLCS were calibrated and validated using existing physical modeling data (α = 500 and β = 1.0, with varying porosity based on the Cubipod shape), while the effect of the basin and vertical seawall was determined fully numerically. The crest freeboard (Rc), crest width (B), and basin length (LB) were the main geometrical parameters that influenced the performance of the HLCS in reducing overtopping. An exponential decay was observed in the overtopping discharge when the values of these geometrical parameters increased. As LB increased, this decay was primarily due to the dissipation of the broken-wave bores. The largest gradient in the predicted overtopping discharge was noted at Rc/Hs,i ≈ 0, B/Hs,i ≈ 4.5, and LB/Lp ≈ 1.2, where Hs,i is the incident significant wave height and Lp is the peak wavelength in the basin.","CFD; Cubipod concrete elements; Homogeneous low-crested structure; OpenFOAM; Seawall overtopping; Wave transmission","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:64b92602-8cc0-4ae6-ba59-0f18fc22122e","http://resolver.tudelft.nl/uuid:64b92602-8cc0-4ae6-ba59-0f18fc22122e","Physics-Informed Neural Networks to Model and Control Robots: A Theoretical and Experimental Investigation","Liu, J. (TU Delft Learning & Autonomous Control); Borja, Pablo (Plymouth University); Della Santina, C. (TU Delft Learning & Autonomous Control; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR))","","2024","This work concerns the application of physics-informed neural networks to the modeling and control of complex robotic systems. Achieving this goal requires extending physics-informed neural networks to handle nonconservative effects. These learned models are proposed to combine with model-based controllers originally developed with first-principle models in mind. By combining standard and new techniques, precise control performance can be achieved while proving theoretical stability bounds. These validations include real-world experiments of motion prediction with a soft robot and trajectory tracking with a Franka Emika Panda manipulator.","dissipation; Euler–Lagrange equations; Hamiltonian neural networks; Lagrangian neural networks; model-based control; physics-informed neural networks; port-Hamiltonian systems","en","journal article","","","","","","","","","","","Learning & Autonomous Control","","",""
"uuid:58fa63b1-db8f-49c1-b034-cd870f2c7cd8","http://resolver.tudelft.nl/uuid:58fa63b1-db8f-49c1-b034-cd870f2c7cd8","Can grassroots movements in water conflicts drive socio-technical transitions in water management systems?","Godinez Madrigal, J. (TU Delft Water Resources; IHE Delft Institute for Water Education); Van Cauwenbergh, Nora (IHE Delft Institute for Water Education; Vrije Universiteit Brussel); Ochoa-Garcia, Heliodoro (ITESO Jesuit University of Guadalajara); van der Zaag, P. (TU Delft Water Resources; IHE Delft Institute for Water Education)","","2024","Water conflicts open windows of opportunity for grassroots movements to transform water systems. However, academic fields studying social movements in socio-environmental conflicts are not well equipped to deal with complexity, non-linear dynamics, and emergent properties. Therefore, these fields rarely engage with long-term complex social processes and dynamics leading to systemic socio-technical changes. Researching water conflicts driven by grassroots movements, we ask whether and how the latter can influence a socio-technical transition of a water management regime. Through an emblematic water conflict in Mexico, we analyse the grassroots movement's trajectory since the conflict´s inception by following the dynamic process of developing agency. Our findings show that throughout the conflict, the grassroots movement accumulated and mobilized diverse capitals to initiate water management strategies and practices that catalysed change in the water management regime by stalling the implementation of large infrastructures. Eventually, this led to the inception of a sustainable and just transition.","Actor-oriented approach; Political ecology; Practice-oriented approach; Social arenas; Social capitals; Zapotillo project","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:3092514a-0bb8-450c-8bfa-619b1bf7cc08","http://resolver.tudelft.nl/uuid:3092514a-0bb8-450c-8bfa-619b1bf7cc08","The effects of three environmental factors on building evacuation time","Kinkel, E. (TU Delft Transport and Planning); van der Wal, C.N. (TU Delft System Engineering); Hoogendoorn, S.P. (TU Delft Transport and Planning)","","2024","Building fires can be considered a risk to the health and safety of occupants. Environmental factors in building fires might affect the speed of an evacuation. Therefore, in this study participants (N = 153) were tested in an experimental design for the effects of (1) a fire alarm, (2) darkness and (3) the use of emergency exit signs on building evacuation time. In addition, the effects of age and gender on evacuation time were investigated. The main results indicate that the combination of a fire alarm, darkness and not illuminated emergency exit signs had a significant negative influence on evacuation time, namely an increase in evacuation time of 26.6% respectively 28.1%. Another important finding is that age had a significant negative effect on evacuation time. The increase in evacuation time was at least 30.4% for participants aged 56 years or older compared to participants aged 18–25 years. For gender no significant effect was found. Building and safety managers can use these results by including longer evacuation time considerations – based on darkness and older age – in their evacuation plans. Future research should focus further on investigating the effects of personal and psychological characteristics on evacuation behaviour and evacuation time.","Building evacuation time; Emergency exit signage; Evacuation; Experiment; Fire alarm; Visibility","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:4b5ccb22-678b-451b-bf41-8671b36e01c9","http://resolver.tudelft.nl/uuid:4b5ccb22-678b-451b-bf41-8671b36e01c9","A One-Way Car-Sharing Based Approach for Combined Shared Mobility of Freight and Passengers","Anis, Summair (University of Genova); Sacco, Nicola (University of Genova); Saeednia, M. (TU Delft Transport and Planning)","","2024","Climate change stresses the need for research and development of innovative sustainable mobility solutions that provide reliable and convenient door-to-door services for both passengers and freight. The increase in urban population and the popularity of e-commerce further highlights the need for action. In this regard, crowd-shipping is often perceived as an efficient, cost-effective, and sustainable alternative (or complement) to the management of urban freight mobility through efficient utilization of current transportation capacities. In this framework, inspired by the concept of MaaS (Mobility as a Service) in integrating various forms of transport and transport-related services into a single on-demand mobility service, this paper proposes a car-sharing-based service for the combined mobility of passengers and freight. In doing so, one-way car-sharing and crowd-shipping concepts are integrated in order to serve part of the existing freight demand in a sustainable and cost-efficient way for users, societies, and the environment. An optimization model is proposed to optimally plan the activation of one-way car-sharing and crowd-shipping services and to determine the optimal number of vehicles to assign to them. Such decisions are aimed at minimizing the total imbalance by serving passenger and freight demand during different time periods. In doing so, the willingness of users to carry freight in their vehicles is also taken into consideration. The capability of the proposed approach is evaluated through representative numerical examples aimed at showing the impact of the model parameters on the solution.","crowd-shipping; integrated mobility solutions; shared mobility; sustainable mobility","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:59b02ec9-5c03-4b86-b8b8-9e886a7a4e2c","http://resolver.tudelft.nl/uuid:59b02ec9-5c03-4b86-b8b8-9e886a7a4e2c","2D and 3D Modelling Strategies to Reproduce the Response of Historical Masonry Buildings Subjected to Settlements","Prosperi, A. (TU Delft Applied Mechanics); Longo, M. (TU Delft Applied Mechanics); Korswagen, Paul A. (TU Delft Applied Mechanics); Korff, M. (TU Delft Geo-engineering); Rots, J.G. (TU Delft Applied Mechanics)","","2024","In this study, 2D and 3D modelling strategies are used to represent the behaviour of historical masonry buildings on strip foundations undergoing settlements. The application focuses on a two-story building, typical of the Dutch architectural heritage. An improved 2D modelling is presented: It includes the effect of the lateral walls to replicate the response of the detailed 3D models. The masonry strip foundation is modelled and supported by a no-tension interface, which represents the soil-foundation interaction. Two settlement configurations, hogging and sagging, are applied to the models, and their intensity is characterized using their angular distortion. The improved 2D model that includes the stiffness and weight of the lateral walls agrees in terms of displacements, stress and damage with the detailed 3D models. Conversely, the simplified 2D façade models without lateral walls exhibit different cracking, and damage from 2 to 7 times lower at an applied angular distortion of 2‰ (1/500). The improved 2D model requires less computational and modelling burden, resulting in analyses from 9 to 40 times faster than the 3D models. The results prove the importance of identifying and including the 3D effects that affect the response of structures subjected to settlements.","damage; masonry structures; numerical modelling; settlements","en","journal article","","","","","","","","","","","Applied Mechanics","","",""
"uuid:16582a99-0526-4e72-8383-0e74aeeb7784","http://resolver.tudelft.nl/uuid:16582a99-0526-4e72-8383-0e74aeeb7784","2D Ge2Se2P4 Monolayer: A Versatile Photocatalyst for Sustainable Water Splitting","Vu, Tuan V. (Van Lang University); Hieu, Nguyen N. (Duy Tan University); Vo, Dat D. (Van Lang University); Kartamyshev, A. I. (Van Lang University); Tong, Hien D. (Vietnamese-German University); Trinh, Thuat T. (Norwegian University of Science and Technology (NTNU)); Khuong Dien, Vo (National Cheng Kung University); Haman, Zakaryae (Moulay Ismail University); Dey, P. (TU Delft Team Poulumi Dey); Khossossi, N. (TU Delft Team Poulumi Dey)","","2024","This study aims to identify photo-/electrocatalysts that can enhance the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR), which are of utmost importance in electro-/photochemical energy systems, such as solar energy, fuel cells, water electrolyzers, or metal-air batteries. Our study focused on investigating the 2D Ge2Se2P4 monolayer and found that it exhibits a bifunctional photocatalyst with a very high solar-to-hydrogen efficiency. The two-dimensional (2D) Ge2Se2P4 monolayer has superior HER activity compared to that of most 2D materials, and it also outperforms the reference catalysts IrO2(110) and Pt(111) in terms of low overpotential values for ORR and OER mechanisms. Such superior catalytic performance in the 2D Ge2Se2P4 monolayer can be attributed to its electron states, charge transfer process, and suitable band alignments referring to normal hydrogen electrodes. Overall, the study suggests that the Ge2Se2P4 monolayer could be an excellent bifunctional catalyst for advancing photo-/electrochemical energy systems.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-29","","","Team Poulumi Dey","","",""
"uuid:031fc2fe-75d3-43b3-b278-0f5ae3333426","http://resolver.tudelft.nl/uuid:031fc2fe-75d3-43b3-b278-0f5ae3333426","Validation of artificial intelligence-based digital microscopy for automated detection of Schistosoma haematobium eggs in urine in Gabon","Meulah, Brice (Leiden University Medical Center; CERMEL); Oyibo, P.O. (TU Delft Team Michel Verhaegen); Hoekstra, Pytsje T. (Leiden University Medical Center); Mour, Paul Alvyn Nguema (CERMEL; Ecole doctorale regionale d’Afrique centrale en infectiologie tropicale de Franceville); Maloum, Moustapha Nzamba (CERMEL); Laclong Lontchi, Roméo Aimé (CERMEL); Honkpehedji, Yabo Josiane (Leiden University Medical Center; CERMEL; Fondation pour la Recherche Scientifique); Bengtson, Michel (Leiden University Medical Center); Hokke, Cornelis (Leiden University Medical Center); Diehl, J.C. (TU Delft Design for Sustainability)","","2024","Introduction
Schistosomiasis is a significant public health concern, especially in Sub-Saharan Africa. Conventional microscopy is the standard diagnostic method in resource-limited settings, but with limitations, such as the need for expert microscopists. An automated digital microscope with artificial intelligence (Schistoscope), offers a potential solution. This field study aimed to validate the diagnostic performance of the Schistoscope for detecting and quantifying Schistosoma haematobium eggs in urine compared to conventional microscopy and to a composite reference standard (CRS) consisting of real-time PCR and the up-converting particle (UCP) lateral flow (LF) test for the detection of schistosome circulating anodic antigen (CAA).
Methods
Based on a non-inferiority concept, the Schistoscope was evaluated in two parts: study A, consisting of 339 freshly collected urine samples and study B, consisting of 798 fresh urine samples that were also banked as slides for analysis with the Schistoscope. In both studies, the Schistoscope, conventional microscopy, real-time PCR and UCP-LF CAA were performed and samples with all the diagnostic test results were included in the analysis. All diagnostic procedures were performed in a laboratory located in a rural area of Gabon, endemic for S. haematobium.
Results
In study A and B, the Schistoscope demonstrated a sensitivity of 83.1% and 96.3% compared to conventional microscopy, and 62.9% and 78.0% compared to the CRS. The sensitivity of conventional microscopy in study A and B compared to the CRS was 61.9% and 75.2%, respectively, comparable to the Schistoscope. The specificity of the Schistoscope in study A (78.8%) was significantly lower than that of conventional microscopy (96.4%) based on the CRS but comparable in study B (90.9% and 98.0%, respectively).
Conclusion
Overall, the performance of the Schistoscope was non-inferior to conventional microscopy with a comparable sensitivity, although the specificity varied. The Schistoscope shows promising diagnostic accuracy, particularly for samples with moderate to higher infection intensities as well as for banked sample slides, highlighting the potential for retrospective analysis in resource-limited settings.","","en","journal article","","","","","","","","","","","Team Michel Verhaegen","","",""
"uuid:92450650-4918-4713-9660-58e2ad8197a8","http://resolver.tudelft.nl/uuid:92450650-4918-4713-9660-58e2ad8197a8","Responsible Design Thinking for Sustainable Development: Critical Literature Review, New Conceptual Framework, and Research Agenda","Baldassarre, B.R. (TU Delft Industrial Design Engineering; Maastricht University School of Business and Economics); Calabretta, G. (TU Delft Methodologie en Organisatie van Design); Karpen, Ingo Oswald (Karlstad University; University of Adelaide); Bocken, Nancy (Maastricht University School of Business and Economics); Hultink, H.J. (TU Delft Responsible Marketing and Consumer Behavior)","","2024","In the 1960s, influential thinkers defined design as a rational problem-solving approach to deal with the challenges of sustainable human development. In 2009, a design consultant and a business academic selected some of these ideas and successfully branded them with the term “design thinking.” As a result, design thinking has developed into a stream of innovation management research discussing how to innovate faster and better in competitive markets. This article aims to foster a reconsideration of the purposes of design thinking moving forward, in view of the sustainable development challenges intertwined with accelerating innovation in a perpetual economic growth paradigm. To this end, we use a problematization method to challenge innovation management research on design thinking. As part of this method, we first systematically collect and critically analyze the articles in this research stream. We uncover a prominent focus on economic impact, while social and environmental impacts remain largely neglected. To overcome this critical limitation, we integrate design thinking with responsible innovation theorizing. We develop a framework for responsible design thinking, explaining how to apply this approach beyond a private interest and competitive advantage logic, to address sustainable development challenges, such as climate change, resource depletion, poverty, and injustice. The framework contributes to strengthening the practical relevance of design thinking and its theoretical foundations. To catalyze this effort, we propose an agenda for future research.","Circular economy; Design; Responsible business; Responsible innovation; Sustainability; Sustainable innovation","en","review","","","","","","","","","Industrial Design Engineering","","Methodologie en Organisatie van Design","","",""
"uuid:2c383e2a-2ac6-4a8b-95ba-41ef163c9382","http://resolver.tudelft.nl/uuid:2c383e2a-2ac6-4a8b-95ba-41ef163c9382","Circular economy as crisis response: A primer","Hartley, Kris (City University of Hong Kong); Baldassarre, B.R. (TU Delft Responsible Marketing and Consumer Behavior; Maastricht University School of Business and Economics; Roskilde University); Kirchherr, Julian (Universiteit Utrecht; Roskilde University; Cambridge University Press)","","2024","The early 2020s have been characterized by multiple convergent crises, including the Covid-19 pandemic and economic fallout of mitigation measures, Russia's invasion of Ukraine, and the ongoing sustainability and climate change crisis. This article discusses how the concept of the circular economy can inform responses to such crises by addressing four elements of a socio-economic system: technological innovation, supply chains and markets, public policy, and consumer behaviour. Synthesizing emerging insights from the scholarly and policymaking arenas, the article identifies the following ways that the circular economy concept can be effectively framed as crisis response: focusing on circularity in a more holistic way, adopting global value chains as the primary unit of analysis, pinpointing specific circularity aspects like drivers and barriers in value chains and business models, and extending the prevailing focus on technical aspects and material flows to often overlooked trade and geopolitical considerations. This discussion aims to articulate lessons for industry, policymakers, and scholars in leveraging a circularity approach to address the world's most pressing issues.","Circular economy; Climate change; Covid-19; Crisis management; Sustainability; Ukraine invasion","en","review","","","","","","","","","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:1bee8b2a-4c88-42ce-bda5-8e745bd5a895","http://resolver.tudelft.nl/uuid:1bee8b2a-4c88-42ce-bda5-8e745bd5a895","Developing the Healthy Actions and Lifestyles to Avoid Dementia or Hispanos y el ALTo a la Demencia program","Moukarzel, Sara (University of California); Zlatar, Zvinka Z. (University of California); Hartman, Sheri J. (University of California); Lomas, J.D. (TU Delft Design Aesthetics); Feldman, Howard H. (University of California); Banks, Sarah J. (University of California)","","2024","INTRODUCTION: With Alzheimer's disease and related dementias (ADRD) representing an enormous public health challenge, there is a need to support individuals in learning about and addressing their modifiable risk factors (e.g., diet, sleep, and physical activity) to prevent or delay dementia onset. However, there is limited availability for evidence-informed tools that deliver both quality education and support for positive behavior change such as by increasing self-efficacy and personalizing goal setting. Tools that address the needs of Latino/a, at higher risk for ADRD, are even more scarce. METHODS: We established a multidisciplinary team to develop the Healthy Actions and Lifestyles to Avoid Dementia or Hispanos y el ALTo a la Demencia (HALT-AD) program, a bilingual online personalized platform to educate and motivate participants to modify their risk factors for dementia. Grounded in social cognitive theory and following a cultural adaptation framework with guidance from a community advisory board, we developed HALT-AD iteratively through several cycles of rapid prototype development, user-centered evaluation through pilot testing and community feedback, and refinement. RESULTS: Using this iterative approach allowed for more than 100 improvements in the content, features, and design of HALT-AD to improve the program's usability and alignment with the interests and educational/behavior change support needs of its target audience. Illustrative examples of how pilot data and community feedback informed improvements are provided. DISCUSSION: Developing HALT-AD iteratively required learning through trial and error and flexibility in workflows, contrary to traditional program development methods that rely on rigid, pre-set requirements. In addition to efficacy trials, studies are needed to identify mechanisms for effective behavior change, which might be culturally specific. Flexible and personalized educational offerings are likely to be important in modifying risk trajectories in ADRD.","behavior change; dementia; digital learning; education; health equity; LatinX; modifiable risk factors; online program; risk reduction; social cognitive theory","en","journal article","","","","","","","","","","","Design Aesthetics","","",""
"uuid:12d78965-608e-44fe-af1e-fc7fe84a19fd","http://resolver.tudelft.nl/uuid:12d78965-608e-44fe-af1e-fc7fe84a19fd","Bone cell response to additively manufactured 3D micro-architectures with controlled Poisson's ratio: Auxetic vs. non-auxetic meta-biomaterials","Yarali, E. (TU Delft Biomaterials & Tissue Biomechanics); Klimopoulou, M. (TU Delft Biomaterials & Tissue Biomechanics); David, M.K. (TU Delft ChemE/O&O groep); Boukany, P. (TU Delft ChemE/Product and Process Engineering); Staufer, U. (TU Delft Micro and Nano Engineering); Fratila-Apachitei, E.L. (TU Delft Biomaterials & Tissue Biomechanics); Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics); Accardo, A. (TU Delft Micro and Nano Engineering); Mirzaali, Mohammad J. (TU Delft Biomaterials & Tissue Biomechanics)","","2024","The Poisson's ratio and elastic modulus are two parameters determining the elastic behavior of biomaterials. While the effects of elastic modulus on the cell response is widely studied, very little is known regarding the effects of the Poisson's ratio. The micro-architecture of meta-biomaterials determines not only the Poisson's ratio but also several other parameters that also influence cell response, such as porosity, pore size, and effective elastic modulus. It is, therefore, very challenging to isolate the effects of the Poisson's ratio from those of other micro-architectural parameters. Here, we computationally design meta-biomaterials with controlled Poisson's ratios, ranging between -0.74 and +0.74, while maintaining consistent porosity, pore size, and effective elastic modulus. The 3D meta-biomaterials were additively manufactured at the micro-scale using two-photon polymerization (2PP), and were mechanically evaluated at the meso‑scale. The response of murine preosteoblasts to these meta-biomaterials was then studied using in vitro cell culture models. Meta-biomaterials with positive Poisson's ratios resulted in higher metabolic activity than those with negative values. The cells could attach and infiltrate all meta-biomaterials from the bottom to the top, fully covering the scaffolds after 17 days of culture. Interestingly, the meta-biomaterials exhibited different cell-induced deformations (e.g., shrinkage or local bending) as observed via scanning electron microscopy. The outcomes of osteogenic differentiation (i.e., Runx2 immunofluorescent staining) and matrix mineralization (i.e., Alizarin red staining) assays indicated the significant potential impact of these meta-biomaterials in the field of bone tissue engineering, paving the way for the development of advanced bone meta-implants. Statement of significance: We studied the influence of Poisson's ratio on bone cell response in meta-biomaterials. While elastic modulus effects are well-studied, the impact of Poisson's ratio, especially negative values found in architected biomaterials, remains largely unexplored. The complexity arises from intertwined micro-architectural parameters, such as porosity and elastic modulus, making it challenging to isolate the Poisson's ratio. To overcome this limitation, this study employed rational computational design to create meta-biomaterials with controlled Poisson's ratios, alongside consistent effective elastic modulus, porosity, and pore size. The study reveals that two-photon polymerized 3D meta-biomaterials with positive Poisson's ratios displayed higher metabolic activity, while all the developed meta-biomaterials supported osteogenic differentiation of preosteoblasts as well as matrix mineralization. The outcomes pave the way for the development of advanced 3D bone tissue models and meta-implants.","Cell differentiation; Meta-biomaterials; Metabolic activity; Poisson's ratio; Preosteoblasts; Two-photon polymerization","en","journal article","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:f6ac2c62-2518-4e42-9c7b-3e6616121bb3","http://resolver.tudelft.nl/uuid:f6ac2c62-2518-4e42-9c7b-3e6616121bb3","Public participation in futuring: A systematic literature review","Barendregt, L.E. (TU Delft Design Aesthetics); Bendor, R. (TU Delft Design Conceptualization and Communication); Van Eekelen, Bregje F. (TU Delft Design Aesthetics; Erasmus Universiteit Rotterdam)","","2024","Against the background of continuous calls to democratize futures research and practice, this paper reports the results of a systematic literature review of the involvement of publics in participatory futuring processes. The paper considers three key research questions: Who participates in public futuring processes? Why are publics included in these processes? And what roles do they occupy? By considering practices of participation in futuring, we aim to build a comprehensive picture of the participatory futuring landscape and highlight elements of process design that may enhance or diminish a process's democratic potential. We conclude by suggesting directions for possible future research that could serve the field's continuing desire to democratize and further integrate participatory and critical approaches to futuring.","critical futures; Democratize; Empowerment; Inclusion; Literature review; Participatory futuring; Public","en","review","","","","","","","","","","","Design Aesthetics","","",""
"uuid:26134021-9159-423c-a8b1-5bcf5621938b","http://resolver.tudelft.nl/uuid:26134021-9159-423c-a8b1-5bcf5621938b","Statistically Distinct Plans for Multi-Objective Task Assignment","Wilde, N. (TU Delft Learning & Autonomous Control); Alonso-Mora, J. (TU Delft Learning & Autonomous Control)","","2024","We study the problem of finding statistically distinct plans for stochastic task assignment problems such as online multi-robot pickup and delivery (MRPD) when facing multiple competing objectives. In many real-world settings robot fleets do not only need to fulfil delivery requests, but also have to consider auxiliary objectives such as energy efficiency or avoiding human-centered work spaces. We pose MRPD as a multi-objective optimization problem where the goal is to find MRPD policies that yield different trade-offs between given objectives. There are two main challenges: 1) MRPD is computationally hard, which limits the number of trade-offs that can reasonably be computed, and 2) due to the random task arrivals, one needs to consider statistical variance of the objective values in addition to the average. We present an adaptive sampling algorithm that finds a set of policies which i) are approximately optimal, ii) approximate the set of all optimal solutions, and iii) are statistically distinguishable. We prove completeness and adapt a state-of-the-art MRPD solver to the multi-objective setting for three example objectives. In a series of simulation experiments we demonstrate the advantages of the proposed method compared to baseline approaches and show its robustness in a sensitivity analysis. The approach is general and could be adapted to other multi-objective task assignment and planning problems under uncertainty.","Costs; Linear programming; Multi-Objective Optimization; Multi-Robot Task Assignment; Optimization; Path Planning for Multiple Mobile Robots; Pickup and Delivery; Planning; Quality of service; Robots; Task analysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-29","","","Learning & Autonomous Control","","",""
"uuid:d6f6758f-b484-4373-92d3-4b37b32ebee7","http://resolver.tudelft.nl/uuid:d6f6758f-b484-4373-92d3-4b37b32ebee7","The relationship between linearised 3D and 2DH models for tidally dominated shallow waters","Rozendaal, M.C. (TU Delft Human Information Communication Design); Dijkstra, Y.M. (TU Delft Mathematical Physics); Schuttelaars, H.M. (TU Delft Mathematical Physics)","","2024","The water motion computed using 3D and 2DH models in tidally dominated shallow waters can, in some cases, differ significantly. In 2DH models, bed friction is typically parametrised in terms of the depth-averaged velocity, whereas in 3D models, typically the near-bed velocity is used. This difference causes the bed shear stress in 2DH models to point towards the depth-averaged velocity, whereas in 3D models, it points towards the near-bed velocity, which are not necessarily the same. Focussing on linearised barotropic models, we derive an exact friction parametrisation for 2DH models such that the same depth-averaged dynamics are described as in the corresponding 3D model. The result is a convolutional friction formulation where the instantaneous friction depends on the present and past velocities, thus modifying the traditional 2DH friction formulation that only depends on the present depth-averaged velocity. In the case of harmonic (tidal) waves, this parametrisation has a clear physical interpretation and shows that the near-bed velocity should be parametrised as a rotated, deformed and phase shifted variant of the depth-averaged velocity. We demonstrate that in certain regions of the parameter space, it may be impossible to calibrate a 2DH model that uses a traditional friction law to reproduce the water levels from a 3D model, showing that the 3D friction formulation can be crucial to capture the 3D dynamics within a depth-averaged model. This phenomenon is explored in detail in a narrow well-mixed estuary.","2DH model; 3D friction formulation; 3D model; Idealised model","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Human Information Communication Design","","",""
"uuid:00e76b21-675a-424a-9721-890063492f04","http://resolver.tudelft.nl/uuid:00e76b21-675a-424a-9721-890063492f04","Training and Testing Texture Similarity Metrics for Structurally Lossless Compression","Zhang, Kaixuan (Northwestern University); Shi, Zhaochen (Northwestern University); Zujovic, Jana (Northwestern University); de Ridder, H. (TU Delft Human Information Communication Design); van Egmond, R. (TU Delft Human Information Communication Design); Neuhoff, David L. (University of Michigan); Pappas, T. (TU Delft Human Information Communication Design)","","2024","We present a systematic approach for training and testing structural texture similarity metrics (STSIMs) so that they can be used to exploit texture redundancy for structurally lossless image compression. The training and testing is based on a set of image distortions that reflect the characteristics of the perturbations present in natural texture images. We conduct empirical studies to determine the perceived similarity scale across all pairs of original and distorted textures. We then introduce a data-driven approach for training the Mahalanobis formulation of STSIM based on the resulting annotated texture pairs. Experimental results demonstrate that training results in significant improvements in metric performance. We also show that the performance of the trained STSIM metrics is competitive with state of the art metrics based on convolutional neural networks, at substantially lower computational cost.","Databases; Distortion; Distortion measurement; Image coding; Measurement; Redundancy; Training","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-15","","","Human Information Communication Design","","",""
"uuid:8274d563-959c-474f-979d-878bfb0b1790","http://resolver.tudelft.nl/uuid:8274d563-959c-474f-979d-878bfb0b1790","A network analysis of factors influencing the purchase intentions for refurbished electronics","Wallner, T.S. (TU Delft Responsible Marketing and Consumer Behavior); Haslbeck, Jonas M.B. (Universiteit Maastricht; Universiteit van Amsterdam); Magnier, L.B.M. (TU Delft Responsible Marketing and Consumer Behavior); Mugge, R. (TU Delft Responsible Marketing and Consumer Behavior; Universiteit van Amsterdam)","","2024","Refurbishment can extend the lifetime of an electronic product and reduce its environmental footprint. However, consumers often perceive refurbished electronics as less attractive than new ones, resulting in lower purchase intentions. While prior research has identified several factors that influence consumer choices regarding refurbished electronics, we lack understanding of the interrelations between the different factors related to the consumer, product and context. To model the complex interplay of the factors involved in the intention to purchase refurbished speakers and earbuds, we conducted a survey with 1801 participants. A network encompassing both product categories revealed that the most central factors influencing the intention to purchase refurbished electronics were the product category, the perceived risk and the perception that refurbished electronics are uncomfortable to use because they remind the consumer of their prior user (territorial contamination). For refurbished earbuds, participants' concerns about territorial and hygienic contamination had the strongest negative relations to purchase intentions. For refurbished speakers, the purchase intentions were most negatively related to their perceived risk and positively related to their financial attractiveness. Hence, strategies aiming to enhance the consumer acceptance of refurbished electronics should aim at reducing risks and contamination concerns. Potential strategies to reduce the risks associated with refurbished electronics are discussed.","Refurbished electronics; Consumer acceptance; Network analysis; Circular economy; Sustainable consumer behaviour","en","journal article","","","","","","","","","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:951e4e7e-6dd0-4836-918f-c2a2f620b32f","http://resolver.tudelft.nl/uuid:951e4e7e-6dd0-4836-918f-c2a2f620b32f","Design of railway transition zones: A novel energy-based criterion","Jain, A. (TU Delft Dynamics of Structures); Metrikine, A. (TU Delft Engineering Structures); Steenbergen, M.J.M.M. (TU Delft Mechanics and Physics of Structures); van Dalen, K.N. (TU Delft Dynamics of Structures)","","2024","Railway transition zones (RTZs) experience higher rates of degradation compared to open tracks, which leads to increased maintenance costs and reduced availability. Despite existing literature on railway track assessment and maintenance, effective design solutions for RTZs are still limited. Therefore, a robust design criterion is required to develop effective solutions. This paper presents a two-step approach for the formulation of a preliminary-design criterion to delay the onset of processes leading to uneven track geometry in RTZs. Firstly, a systematic analysis of each track component in a RTZ is performed by examining spatial and temporal variations in kinematic responses, stresses and energies using a finite element model of an embankment-bridge transition. Secondly, the study proposes an energy-based criterion to be assessed using a model with linear elastic material behavior and states that an amplification in the total train energy in the proximity of the transition interface is an indicator of increased (and thus non-uniform) degradation in RTZs compared to the open tracks. The correlation between the total strain energy (assessed in the model with linear material behaviour) and the permanent irreversible deformations is demonstrated using a model with non-linear elastoplastic material behavior of the ballast layer. In the end, it is claimed that minimising the magnitude of total strain energy will lead to reduced degradation and a uniform distribution of total strain energy in each trackbed layer along the longitudinal direction of the track will ensure uniformity in the track geometry.","Railway transition zones; Track degradation; Finite element model; Energy analysis; Design criterion; Strain energy","en","journal article","","","","","","","","","","Engineering Structures","Dynamics of Structures","","",""
"uuid:023b1c6c-3d52-4354-a958-0880d7bf9bdc","http://resolver.tudelft.nl/uuid:023b1c6c-3d52-4354-a958-0880d7bf9bdc","The Funnel of Game Design – An Adaptive Game Design Approach for Complex Systems","Freese, M. (TU Delft Policy Analysis; Otto-von-Guericke University); Lukosch, H.K. (University of Canterbury)","","2024","Background: In a world of ever-increasing complexity, organizations and people have an ever-increasing need for support systems that help them understand and shape the world around them. While simulation game design derived from the very idea to propose an instrument able to address complexity, seminal approaches dealt with a different level of complexity. In a networked, digitalized world, complexity has increased, and traditional approaches towards designing games show certain shortcomings that have to be overcome. Aim: This article proposes a new process of game design for complex problems and complex systems that can both be used by game designers as well as the scientific community in the field. This process is represented within a framework, based on two parts. The so-called ‘Funnel of Game Design’ based on the IDEAS approach represents the process of problem derivation, while the ‘House of Game Design’ also covers possible steps towards the final game product and process, including de-briefing and evaluation. Method: Based on hands-on experiences and related work, we developed several steps of a game design process (IDEAS approach). In face-to-face interviews, we discussed the first version of the framework with experts in the field of simulation game studies. Results: This process led to the framework presented in this article, which shows the steps of problem derivation as well as challenges that can occur, and proposes adaptive methods to overcome these challenges. The framework includes elements that support the definition of complex problems, and their translation into game designs. Recommendation: We recommend practitioners and scientists to apply the new framework presented here in their efforts to define the underlying problem that should be addressed by an envisioned simulation game, and in translating this into a valid, engaging and meaningful game experience.","analytical science; complex systems; design framework; design science; simulation games","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:66739aaf-879a-4044-af8d-6d9449e9455f","http://resolver.tudelft.nl/uuid:66739aaf-879a-4044-af8d-6d9449e9455f","Nanopore Characteristics of Barakar Formation Shales and Their Impact on the Gas Storage Potential of Korba and Raniganj Basins in India","Kumar, Shubham (Indian Institute of Technology Bombay; Monash University); Chandra, D. (TU Delft Applied Geophysics and Petrophysics); Hazra, Bodhisatwa (Christian-Albrechts-Universität zu Kiel; Central Institute of Mining and Fuel Research); Vishal, Vikram (Indian Institute of Technology Bombay); Pathegama Gamage, Ranjith (Monash University)","","2024","Lithologically diverse shales were collected from two different proliferous basins, namely, the Korba (SM) and Raniganj Basin (BK) in India, and were experimented with at an isothermal condition using CO2 and N2 as probe gases in the low-pressure gas adsorption method, demonstrating the disparity between shale pore attributes and surface roughness. The Korba Basin is one of the potential sites for gas storage and production in India and needs to be explored in terms of pore statistics. Literature reviews demonstrate that pore characteristics in shale changes with depth, organic matter, and mineral composition, which can elucidate the gas storage potential for anthropogenic CO2 storage. Gas adsorption capacity and surface roughness are directly associated with the difference in organic and mineral compositions, which certainly affects the phase distribution of flow regimes in shale reservoirs. The result determines that micropore and mesopore attributes are in good correlation with the TOC and clay minerals, respectively. SM shale shows 30-37% higher micropore attributes and 17-19% lower mesopore attributes than those of BK shales. Furthermore, the siderite content shows a variance in the pore size distribution in BK shales. The fractal dimension (Ds) is evaluated based on the N2 adsorption isotherm curve using the Frenkel-Halsey-Hill model. SM shales show a strong correlation with both micropores and mesopores at low relative pressure regimes, while BK shales depict their dominance with mesopores at the high relative pressure regime. Therefore, this research provides a preliminary attempt to determine the influence of changes in the depth, surface roughness, and organic and mineral compositions on shales. However, a complete extrapolation of other reservoir factors, viz., seam thickness, shale-water interaction, and permeability variation at reservoir conditions, is vital to unlocking the technical and environmental feasibility of CO2 storage and gas production in these basins.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-22","","","Applied Geophysics and Petrophysics","","",""
"uuid:891fb906-9597-4543-ac66-99742b587c25","http://resolver.tudelft.nl/uuid:891fb906-9597-4543-ac66-99742b587c25","Utilizing Gold Nanoparticle Decoration for Enhanced UV Photodetection in CdS Thin Films Fabricated by Pulsed Laser Deposition: Exploiting Plasmon-Induced Effects","Belaid, Walid (Selçuk University); Gezgin, Serap Yiğit (Selçuk University); Basyooni, Mohamed A. (TU Delft Dynamics of Micro and Nano Systems; National Research Institute of Astronomy and Geophysics; Necmettin Erbakan University); Eker, Yasin Ramazan (Necmettin Erbakan University); Kılıç, Hamdi Şükür (Selçuk University)","","2024","UV sensors hold significant promise for various applications in both military and civilian domains. However, achieving exceptional detectivity, responsivity, and rapid rise/decay times remains a notable challenge. In this study, we address this challenge by investigating the photodetection properties of CdS thin films and the influence of surface-deposited gold nanoparticles (AuNPs) on their performance. CdS thin films were produced using the pulsed laser deposition (PLD) technique on glass substrates, with CdS layers at a 100, 150, and 200 nm thickness. Extensive characterization was performed to evaluate the thin films’ structural, morphological, and optical properties. Photodetector devices based on CdS and AuNPs/CdS films were fabricated, and their performance parameters were evaluated under 365 nm light illumination. Our findings demonstrated that reducing CdS layer thickness enhanced performance concerning detectivity, responsivity, external quantum efficiency (EQE), and photocurrent gain. Furthermore, AuNP deposition on the surface of CdS films exhibited a substantial influence, especially on devices with thinner CdS layers. Among the configurations, AuNPs/CdS(100 nm) demonstrated the highest values in all evaluated parameters, including detectivity (1.1×1012 Jones), responsivity (13.86 A/W), EQE (47.2%), and photocurrent gain (9.2).","UV sensors; Au nanoparticles; CdS thin films; photodetection; pulsed laser deposition","en","journal article","","","","","","","","","","","Dynamics of Micro and Nano Systems","","",""
"uuid:aaf79cd7-5d25-4c12-8ccb-45a0345f48f9","http://resolver.tudelft.nl/uuid:aaf79cd7-5d25-4c12-8ccb-45a0345f48f9","The validity of simplifying gaming simulations","van Haaften, M.A. (TU Delft System Engineering; InHolland); Lefter, I. (TU Delft System Engineering); van Kooten, O. (Wageningen University & Research; InHolland); Brazier, F.M. (TU Delft System Engineering)","","2024","Simplifications of the real world affect the validity and reliability of gaming simulations. This challenges the application of gaming simulations as an instrument for experiential learning, reflective practices and data collection. This study investigates the effects of simplification on extracting tacit knowledge from human behavior by answering the research question: Can tacit knowledge in a simplified design of a gaming simulation be transferred without compromising the validity and reliability corresponding to the real-world complexity? By applying a participatory design a gaming simulation is tested as an instrument to extract tacit knowledge. To test and evaluate the validity of this application, simulation sessions have been performed with experts from the field. In simplifying reality, participants' participation emphasized that the most accurate representation of reality is a prerequisite for capturing tacit knowledge. This in turn contributes again to the validity of the simulation design. The results show that simplification of the real world didn't affect participants' perspective on the use of the gaming simulation as an experiential tool to enable learning processes or create awareness. And that a simplified simulation design, is still valid in addressing the real-world complexity, with minimization of the level of abstraction and maximization of the truthfulness.","Gaming simulation design; Horticulture; Participatory design; Simulation validity; Tacit knowledge","en","journal article","","","","","","","","","","","System Engineering","","",""
"uuid:24e4ed3c-9dc2-4405-9b87-ba9d9588f02b","http://resolver.tudelft.nl/uuid:24e4ed3c-9dc2-4405-9b87-ba9d9588f02b","Generalized Model and Deep Reinforcement Learning-Based Evolutionary Method for Multitype Satellite Observation Scheduling","Song, Yanjie (Xidian University); Ou, Junwei (Xiangtan University, Xiangtan); Pedrycz, Witold (University of Alberta; Polish Academy of Sciences; Istinye University); Suganthan, Ponnuthurai Nagaratnam (Qatar University); Wang, X. (TU Delft Learning & Autonomous Control); Xing, Lining (Xidian University); Zhang, Yue (Beihang University)","","2024","Multitype satellite observation, including optical observation satellites, synthetic aperture radar (SAR) satellites, and electromagnetic satellites, has become an important direction in integrated satellite applications due to its ability to cope with various complex situations. In the multitype satellite observation scheduling problem (MTSOSP), the constraints involved in different types of satellites make the problem challenging. This article proposes a mixed-integer programming model and a generalized profit representation method in the model to effectively cope with the situation of multiple types of satellite observations. To obtain a suitable observation plan, a deep reinforcement learning-based genetic algorithm (DRL-GA) is proposed by combining the learning method and genetic algorithm. The DRL-GA adopts a solution generation method to obtain the initial population and assist with local search. In this method, a set of statistical indicators that consider resource utilization and task arrangement performance are regarded as states. By using deep neural networks to estimate the <inline-formula> <tex-math notation=""LaTeX"">$Q$</tex-math> </inline-formula> value of each action, this method can determine the preferred order of task scheduling. An individual update strategy and an elite strategy are used to enhance the search performance of DRL-GA. Simulation results verify that DRL-GA can effectively solve the MTSOSP and outperforms the state-of-the-art algorithms in several aspects. This work reveals the advantages of the proposed generalized model and scheduling method, which exhibit good scalability for various types of observation satellite scheduling problems.","Combinatorial optimization problem; deep reinforcement learning (DRL); Earth Observing System; evolutionary algorithm (EA); generalized model; Genetic algorithms; multitype; Optimization; satellite observation; Satellites; scheduling; Sociology; Statistics; Task analysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-15","","","Learning & Autonomous Control","","",""
"uuid:bc63aa2f-630e-47f2-a093-8042d697bc88","http://resolver.tudelft.nl/uuid:bc63aa2f-630e-47f2-a093-8042d697bc88","Scalable Photochromic Film for Solar Heat and Daylight Management","Meng, Weihao (University of Chinese Academy of Sciences); Kragt, A.J.J. (TU Delft Architectural Technology; ClimAd Technology B.V.); Gao, Yingtao (University of Chinese Academy of Sciences); Brembilla, E. (TU Delft Environmental & Climate Design); van der Burgt, Julia S. (ClimAd Technology B.V.); Schenning, Albertus P.H.J. (Eindhoven University of Technology); Klein, T. (TU Delft Architectural Technology); van den Ham, E.R. (TU Delft Environmental & Climate Design); Wang, Jingxia (University of Chinese Academy of Sciences)","","2024","The adaptive control of sunlight through photochromic smart windows could have a huge impact on the energy efficiency and daylight comfort in buildings. However, the fabrication of inorganic nanoparticle and polymer composite photochromic films with a high contrast ratio and high transparency/low haze remains a challenge. Here, a solution method is presented for the in situ growth of copper-doped tungsten trioxide nanoparticles in polymethyl methacrylate, which allows a low-cost preparation of photochromic films with a high luminous transparency (luminous transmittance Tlum = 91%) and scalability (30 × 350 cm2). High modulation of visible light (ΔTlum = 73%) and solar heat (modulation of solar transmittance ΔTsol = 73%, modulation of solar heat gain coefficient ΔSHGC = 0.5) of the film improves the indoor daylight comfort and energy efficiency. Simulation results show that low-e windows with the photochromic film applied can greatly enhance the energy efficiency and daylight comfort. This photochromic film presents an attractive strategy for achieving more energy-efficient buildings and carbon neutrality to combat global climate change.","daylight comfort; energy saving; photochromicity; scalability; smart windows; transparency; tungsten trioxide","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-05","","","Architectural Technology","","",""
"uuid:0ab8d7f0-fa49-45fc-95a6-8c6a5d5432a4","http://resolver.tudelft.nl/uuid:0ab8d7f0-fa49-45fc-95a6-8c6a5d5432a4","Design capability when visioning for transitions: A case study of a new food system","Goss, H. (TU Delft Design Aesthetics); Tromp, N. (TU Delft Design Aesthetics); Schifferstein, Hendrik N.J. (TU Delft Design Aesthetics)","","2024","In recent years, more designers have been engaging in transitions, for which design expertise is used to develop visions of long-term desirable futures. However, little is known about how design expertise is positioned in transition visioning processes. In this case study, we follow a design agency in envisioning a future food system for a consortium working on the food transition. Based on our findings, we unpack several tensions that emerge between the transition context and design expertise. Such as the tension for designers to explore alternative futures that challenge the current system yet support stakeholders in seeing their place in the future. We conclude by reflecting on avenues for methodological development to optimally position design expertise for visioning in transitions.","visioning; transition design; design expertise; design practice; case study","en","journal article","","","","","","","","","","","Design Aesthetics","","",""
"uuid:c2bea36a-b7ff-4ce9-91ca-65206cffe596","http://resolver.tudelft.nl/uuid:c2bea36a-b7ff-4ce9-91ca-65206cffe596","Dynamic wind farm flow control using free-vortex wake models","van den Broek, M.J. (TU Delft Team Jan-Willem van Wingerden); Becker, M. (TU Delft Team Jan-Willem van Wingerden); Sanderse, Benjamin (Centrum Wiskunde & Informatica (CWI)); van Wingerden, J.W. (TU Delft Team Jan-Willem van Wingerden)","","2024","A novel dynamic economic model-predictive control strategy is presented that improves wind farm power production and reduces the additional demands of wake steering on yaw actuation when compared to an industry state-of-the-art reference controller. The novel controller takes a distributed approach to yaw control optimisation using a free-vortex wake model. An actuator-disc representation of the wind turbine is employed and adapted to the wind farm scale by modelling secondary effects of wake steering and connecting individual turbines through a directed graph network. The economic model-predictive control problem is solved on a receding horizon using gradient-based optimisation, demonstrating sufficient performance for realising real-time control. The novel controller is tested in a large-eddy simulation environment and compared against a state-of-the-art look-up table approach based on steady-state model optimisation and an extension with wind direction preview. Under realistic variations in wind direction and wind speed, the preview-enabled look-up table controller yielded the largest gains in power production. The novel controller based on the free-vortex wake produced smaller gains in these conditions while yielding more power under large changes in wind direction. Additionally, the novel controller demonstrated potential for a substantial reduction in yaw actuator usage.","","en","journal article","","","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:fb35fd23-7284-426a-bab9-40729f810962","http://resolver.tudelft.nl/uuid:fb35fd23-7284-426a-bab9-40729f810962","Notable shifts beyond pre-industrial streamflow and soil moisture conditions transgress the planetary boundary for freshwater change","Porkka, Miina (Royal Swedish Academy of Sciences; University of Eastern Finland; Aalto University); Virkki, Vili (Aalto University); Wang-Erlandsson, Lan (Stockholm University; Potsdam Institute for Climate Impact Research); Gerten, Dieter (Humboldt-Universitat zu Berlin; Potsdam Institute for Climate Impact Research); Gleeson, Tom (University of Victoria); Mohan, Chinchu (University of Victoria; University of Saskatchewan); Fetzer, Ingo (Stockholm University); Jaramillo, Fernando (Stockholm University); Staal, Arie (Universiteit Utrecht); van der Ent, R.J. (TU Delft Water Resources)","","2024","Human actions compromise the many life-supporting functions provided by the freshwater cycle. Yet, scientific understanding of anthropogenic freshwater change and its long-term evolution is limited. Here, using a multi-model ensemble of global hydrological models, we estimate how, over a 145-year industrial period (1861–2005), streamflow and soil moisture have deviated from pre-industrial baseline conditions (defined by 5th–95th percentiles, at 0.5° grid level and monthly timestep over 1661–1860). Comparing the two periods, we find an increased frequency of local deviations on ~45% of land area, mainly in regions under heavy direct or indirect human pressures. To estimate humanity’s aggregate impact on these two important elements of the freshwater cycle, we present the evolution of deviation occurrence at regional to global scales. Annually, local streamflow and soil moisture deviations now occur on 18.2% and 15.8% of global land area, respectively, which is 8.0 and 4.7 percentage points beyond the ~3 percentage point wide pre-industrial variability envelope. Our results signify a substantial shift from pre-industrial streamflow and soil moisture reference conditions to persistently increasing change. This indicates a transgression of the new planetary boundary for freshwater change, which is defined and quantified using our approach, calling for urgent actions to reduce human disturbance of the freshwater cycle.","","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:bf89da1d-0ef5-4ec6-b1d0-e39d4bfe3a99","http://resolver.tudelft.nl/uuid:bf89da1d-0ef5-4ec6-b1d0-e39d4bfe3a99","DeltaDTM: A global coastal digital terrain model","Pronk, M.J. (TU Delft Urban Data Science; Deltares); Hooijer, Aljosja (Deltares); Eilander, Dirk (Deltares); Haag, Arjen (Deltares); de Jong, Tjalling (Deltares); Vousdoukas, Michalis (University of the Aegean, Mytilene); Vernimmen, Ronald (Data for Sustainability, Axel); Ledoux, H. (TU Delft Urban Data Science); Eleveld, M.A. (TU Delft Mathematical Geodesy and Positioning; Deltares)","","2024","Coastal elevation data are essential for a wide variety of applications, such as coastal management, flood modelling, and adaptation planning. Low-lying coastal areas (found below 10 m +Mean Sea Level (MSL)) are at risk of future extreme water levels, subsidence and changing extreme weather patterns. However, current freely available elevation datasets are not sufficiently accurate to model these risks. We present DeltaDTM, a global coastal Digital Terrain Model (DTM) available in the public domain, with a horizontal spatial resolution of 1 arcsecond (∼30 m) and a vertical mean absolute error (MAE) of 0.45 m overall. DeltaDTM corrects CopernicusDEM with spaceborne lidar from the ICESat-2 and GEDI missions. Specifically, we correct the elevation bias in CopernicusDEM, apply filters to remove non-terrain cells, and fill the gaps using interpolation. Notably, our classification approach produces more accurate results than regression methods recently used by others to correct DEMs, that achieve an overall MAE of 0.72 m at best. We conclude that DeltaDTM will be a valuable resource for coastal flood impact modelling and other applications.","energy access; energy security; power distribution","en","journal article","","","","","","","","","","","Urban Data Science","","",""
"uuid:e9c748fa-0998-41d9-838f-c2bdb97b7d3a","http://resolver.tudelft.nl/uuid:e9c748fa-0998-41d9-838f-c2bdb97b7d3a","A Novel Composite Sensor for UHF Partial Discharge and Gas State Measurement in GIS","Chen, Huan (Xi’an Jiaotong University); Zhang, Zhaoyu (Xi’an Jiaotong University); Guo, R. (TU Delft High Voltage Technology Group); Han, Xutao (Xi’an Jiaotong University); Zhang, Xuanrui (Xi’an Jiaotong University); Lin, Junhao (Xi’an Jiaotong University)","","2024","The gas state of the insulating gas significantly impacts the development and extent of the partial discharge (PD) in gas-insulated switchgear (GIS). Correlating these two factors allows for a more comprehensive diagnosis of insulation defects. At present, the ultrahigh-frequency (UHF) method has been widely used for PD detection in GIS. However, the measurements of the insulating gas's state in the field are primarily conducted offline or at gas valves, providing ineffective data for reference. To address this challenge, this article introduces a novel composite sensor capable of simultaneous UHF and gas state measurements. Building upon the disk-type UHF sensor structure, the composite sensor integrates a gas state sensing unit with the micro-electromechanical systems (MEMS) sensor as the core. A robust shielding shell is designed through finite element simulation to ensure the safety of the sensor, with the maximum induced voltage and electric field strength on the sensing unit measuring 0.28 V and 414 V/m, respectively. The average UHF measurement sensitivity of the composite sensor reaches 13.3 mm. In addition, the composite sensor exhibits low errors (±0.2 °C, ±3 kPa, and ± 10 μ L/L), high consistency and repeatability in temperature, pressure, and moisture measurement. Finally, the composite sensor has demonstrated its capability to simultaneously and safely detect PD signals and the gas state within GIS.","Combined detection; electromagnetic shielding; gas-insulated switchgear (GIS); gas state; micro-electromechanical systems (MEMS) sensor; ultrahigh frequency (UHF)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-01","","","High Voltage Technology Group","","",""
"uuid:01b73100-531d-4923-8c36-bcbc4b4b1855","http://resolver.tudelft.nl/uuid:01b73100-531d-4923-8c36-bcbc4b4b1855","A matrix-free parallel solution method for the three-dimensional heterogeneous Helmholtz equation","Chen, J. (TU Delft Numerical Analysis); Dwarka, V.N.S.R. (TU Delft Numerical Analysis); Vuik, Cornelis (TU Delft Delft Institute of Applied Mathematics)","","2024","The Helmholtz equation is related to seismic exploration, sonar, antennas, and medical imaging applications. It is one of the most challenging problems to solve in terms of accuracy and convergence due to the scalability issues of the numerical solvers. For 3D large-scale applications, high-performance parallel solvers are also needed. In this paper, a matrix-free parallel iterative solver is presented for the three-dimensional (3D) heterogeneous Helmholtz equation. We consider the preconditioned Krylov subspace methods for solving the linear system obtained from finite-difference discretization. The Complex Shifted Laplace Preconditioner (CSLP) is employed since it results in a linear increase in the number of iterations as a function of the wavenumber. The preconditioner is approximately inverted using one parallel 3D multigrid cycle. For parallel computing, the global domain is partitioned blockwise. The matrix-vector multiplication and preconditioning operator are implemented in a matrix-free way instead of constructing large, memory-consuming coefficient matrices. Numerical experiments of 3D model problems demonstrate the robustness and outstanding strong scaling of our matrix-free parallel solution method. Moreover, the weak parallel scalability indicates our approach is suitable for realistic 3D heterogeneous Helmholtz problems with minimized pollution error.","Helmholtz equation; parallel computation; matrix-free; geometric multigrid; preconditioner; scalability","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-15","","","Numerical Analysis","","",""
"uuid:328d3299-e8f0-42d8-9e72-d983e197d95e","http://resolver.tudelft.nl/uuid:328d3299-e8f0-42d8-9e72-d983e197d95e","Sub-seasonal soil moisture anomaly forecasting using combinations of deep learning, based on the reanalysis soil moisture records","Wang, X. (Chongqing Jiaotong University; Hohai University); Corzo, Gerald (IHE Delft Institute for Water Education); Lü, Haishen (Hohai University); Zhou, Shiliang (Chongqing Jiaotong University); Mao, K. (TU Delft Physical and Space Geodesy); Zhu, Yonghua (Hohai University); Duarte Prieto, F.S. (TU Delft Water Resources; IHE Delft Institute for Water Education); Liu, Mingwen (Hohai University); Su, Jianbin (Chinese Academy of Sciences)","","2024","Sub-seasonal drought forecasting is crucial for early warning in estimating agricultural production and optimizing irrigation management, as forecasting skills are relatively weak during this period. Soil moisture exhibits stronger persistence compared to other climate system quantities, which makes it especially influential in shaping land-atmosphere feedback, thus supplying a unique insight into drought forecasting. Relying on the soil moisture memory, this study investigates the combination of multiple deep-learning modules for sub-seasonal drought indices hindcast in the Huai River basin of China, using long-term ERA5-Land soil moisture records with a noise-assisted data analysis tool. The inter-compared deep-learning models include a hybrid model and a committee machine framework. The results show that the performance of the committee machine framework can be improved with the help of series decomposition and the forecasting skill is not impaired with the lead time increases. Overall, this study highlights the potential of combining deep-learning models with soil moisture memory analysis to improve sub-seasonal drought forecasting.","Committee model; Deep learning; Drought forecasting; Noise-assisted tool; Reanalysis soil moisture","en","journal article","","","","","","","","","","","Physical and Space Geodesy","","",""
"uuid:ea6c29e0-6ebb-4cbd-8192-8bdecaaaf89d","http://resolver.tudelft.nl/uuid:ea6c29e0-6ebb-4cbd-8192-8bdecaaaf89d","Dynamic Mesh Simulations in OpenFOAM: A Hybrid Eulerian–Lagrangian Approach","Pasolari, R. (TU Delft Wind Energy); Ferreira, Carlos (TU Delft Wind Energy); van Zuijlen, A.H. (TU Delft Aerodynamics); Baptista, C.F. (TU Delft Wind Energy)","","2024","The past few decades have witnessed a growing popularity in Eulerian–Lagrangian solvers due to their significant potential for simulating aerodynamic flows, particularly in cases involving strong body–vortex interactions. In this hybrid approach, the two component solvers are mutually coupled in a two-way fashion. Initially, the Lagrangian solver can supply boundary conditions to the Eulerian solver, while the Eulerian solver functions as a corrector for the Lagrangian solution in regions where the latter cannot achieve high accuracy. To utilize such tools effectively, it is vital for them to be capable of handling dynamic mesh movements. This study builds upon the previous research conducted by our team and extends the capabilities of the hybrid solver to handle dynamic meshes. While OpenFOAM, the Eulerian component of this hybrid code, incorporates built-in dynamic mesh properties, certain modifications are necessary to ensure its compatibility with the Lagrangian solver. More specifically, the evolution algorithm of the pimpleFOAM solver needs to be divided into two discrete steps: first, updating the mesh, and later, evolving the solution. This division enables a proper coupling between pimpleFOAM and the Lagrangian solver as an intermediate step. Therefore, the primary objective of this specific paper is to adapt the OpenFOAM solver to meet the demands of the hybrid solver and subsequently validate that the hybrid solver can effectively address dynamic mesh challenges using this approach. This approach introduces a pioneering method for conducting dynamic mesh simulations within the OpenFOAM framework, showcasing its potential for broader applications. To validate the approach, various test cases involving dynamic mesh movements are employed. Specifically, all these cases employ the Lamb–Oseen diffusing vortex, but each case incorporates different types of mesh movements, including translational, rotational, oscillational, and combinations thereof. The results from these cases demonstrate the effectiveness of the proposed OpenFOAM algorithm, with the maximum relative errors —when compared to the analytical solution across all presented cases—capped at (Formula presented.) for the worst-case scenario. This affirms the algorithm’s capability to successfully handle dynamic mesh simulations with the proposed solver.","OpenFOAM; dynamicmeshes; hybrid Eulerian–Lagrangian solvers; vortex particle methods","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:490b742b-aff2-4514-b4c5-a43a5689677b","http://resolver.tudelft.nl/uuid:490b742b-aff2-4514-b4c5-a43a5689677b","The critical variational setting for stochastic evolution equations","Agresti, A. (Institute of Science and Technology Austria); Veraar, M.C. (TU Delft Analysis)","","2024","In this paper we introduce the critical variational setting for parabolic stochastic evolution equations of quasi- or semi-linear type. Our results improve many of the abstract results in the classical variational setting. In particular, we are able to replace the usual weak or local monotonicity condition by a more flexible local Lipschitz condition. Moreover, the usual growth conditions on the multiplicative noise are weakened considerably. Our new setting provides general conditions under which local and global existence and uniqueness hold. In addition, we prove continuous dependence on the initial data. We show that many classical SPDEs, which could not be covered by the classical variational setting, do fit in the critical variational setting. In particular, this is the case for the Cahn–Hilliard equation, tamed Navier–Stokes equations, and Allen–Cahn equation.","Allen–Cahn equation; Cahn–Hilliard equation; Coercivity; Critical nonlinearities; Generalized Burgers equation; Quasi- and semi-linear; Stochastic evolution equations; Stochastic partial differential equations; Swift–Hohenberg equation; Tamed Navier–Stokes; Variational methods","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:2195e3ab-bc08-4b5d-ada8-a864817aecfd","http://resolver.tudelft.nl/uuid:2195e3ab-bc08-4b5d-ada8-a864817aecfd","An omics-based machine learning approach to predict diabetes progression: a RHAPSODY study","Slieker, Roderick C. (Vrije Universiteit Amsterdam; Amsterdam Public Health; Amsterdam Cardiovascular Sciences; Leiden University Medical Center); Münch, Magnus (Vrije Universiteit Amsterdam); Donnelly, Louise A. (University of Dundee); Bouland, G.A. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center); Dragan, Iulian (SIB Swiss Institute of Bioinformatics); Kuznetsov, Dmitry (SIB Swiss Institute of Bioinformatics); Elders, Petra J.M. (Amsterdam Public Health; Amsterdam Cardiovascular Sciences; Amsterdam UMC); Rutter, Guy A. (Nanyang Technological University; Université de Montréal); Ibberson, Mark (SIB Swiss Institute of Bioinformatics)","","2024","Aims/hypothesis: People with type 2 diabetes are heterogeneous in their disease trajectory, with some progressing more quickly to insulin initiation than others. Although classical biomarkers such as age, HbA1c and diabetes duration are associated with glycaemic progression, it is unclear how well such variables predict insulin initiation or requirement and whether newly identified markers have added predictive value. Methods: In two prospective cohort studies as part of IMI-RHAPSODY, we investigated whether clinical variables and three types of molecular markers (metabolites, lipids, proteins) can predict time to insulin requirement using different machine learning approaches (lasso, ridge, GRridge, random forest). Clinical variables included age, sex, HbA1c, HDL-cholesterol and C-peptide. Models were run with unpenalised clinical variables (i.e. always included in the model without weights) or penalised clinical variables, or without clinical variables. Model development was performed in one cohort and the model was applied in a second cohort. Model performance was evaluated using Harrel’s C statistic. Results: Of the 585 individuals from the Hoorn Diabetes Care System (DCS) cohort, 69 required insulin during follow-up (1.0–11.4 years); of the 571 individuals in the Genetics of Diabetes Audit and Research in Tayside Scotland (GoDARTS) cohort, 175 required insulin during follow-up (0.3–11.8 years). Overall, the clinical variables and proteins were selected in the different models most often, followed by the metabolites. The most frequently selected clinical variables were HbA1c (18 of the 36 models, 50%), age (15 models, 41.2%) and C-peptide (15 models, 41.2%). Base models (age, sex, BMI, HbA1c) including only clinical variables performed moderately in both the DCS discovery cohort (C statistic 0.71 [95% CI 0.64, 0.79]) and the GoDARTS replication cohort (C 0.71 [95% CI 0.69, 0.75]). A more extensive model including HDL-cholesterol and C-peptide performed better in both cohorts (DCS, C 0.74 [95% CI 0.67, 0.81]; GoDARTS, C 0.73 [95% CI 0.69, 0.77]). Two proteins, lactadherin and proto-oncogene tyrosine-protein kinase receptor, were most consistently selected and slightly improved model performance. Conclusions/interpretation: Using machine learning approaches, we show that insulin requirement risk can be modestly well predicted by predominantly clinical variables. Inclusion of molecular markers improves the prognostic performance beyond that of clinical variables by up to 5%. Such prognostic models could be useful for identifying people with diabetes at high risk of progressing quickly to treatment intensification. Data availability: Summary statistics of lipidomic, proteomic and metabolomic data are available from a Shiny dashboard at https://rhapdata-app.vital-it.ch. Graphical Abstract: (Figure presented.).","Machine learning; Prediction model; Progression; Type 2 diabetes","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:f3dffda4-099d-4c85-b510-ca3285b06f01","http://resolver.tudelft.nl/uuid:f3dffda4-099d-4c85-b510-ca3285b06f01","Design of Integrated Hybrid Configuration of Modular Multilevel Converter and Marx Generator to Generate Complex Waveforms for Dielectric Testing of Grid Assets","Ganeshpure, D.A. (TU Delft High Voltage Technology Group); Soeiro, Thiago Batista (University of Twente); Ghaffarian Niasar, M. (TU Delft High Voltage Technology Group); Kulkarni, Nitish Milind (Student TU Delft); Bauer, P. (TU Delft DC systems, Energy conversion & Storage); Vaessen, P.T.M. (TU Delft High Voltage Technology Group; KEMA Laboratories)","","2024","This article proposes a new configuration of a modular multilevel converter (MMC) and a Marx generator to generate fast-rising impulse waveforms. This new configuration improves the capabilities of the MMC-based high voltage arbitrary wave shape generator to generate fast-rising impulse since the MMC topology faces many inherent limitations. Similar to the conventional superimposed circuit of the ac transformer or dc rectifier circuit with the Marx generator, three hybrid circuits of MMC and the Marx generator are introduced, where the most optimal choice is made considering the practical aspects of testing, such as the size, cost, and preparation time. Then, a detailed analytical study is performed on the Marx generator circuit and the MMC circuit, and both circuits are coupled together to deliver a complete guideline on choosing various system parameters when the impulse wave shape and the load capacitor are given. The concept of this new hybrid configuration is demonstrated with a scaled-down prototype where the impulse with a rise time of 1 μs is superimposed on different arbitrary wave shapes. Similarly, the MATLAB-Simulink simulation model validates the proposed configuration for a 200, k V dc link voltage and 67 submodules with the desired impulse performance.","Modular Multilevel Converter; Marx generator; Superimposed waveforms; Lightning Impulse","en","journal article","","","","","","","","","","","High Voltage Technology Group","","",""
"uuid:b35ef96d-d772-49ad-87aa-d5b6d0e2337b","http://resolver.tudelft.nl/uuid:b35ef96d-d772-49ad-87aa-d5b6d0e2337b","Structuring Interdigitated Back Contact Solar Cells Using the Enhanced Oxidation Characteristics Under Laser-Doped Back Surface Field Regions","Kuruganti, V.V. (International Solar Energy Research Center (ISC)); Isabella, O. (TU Delft Photovoltaic Materials and Devices); Mihailetchi, Valentin D. (International Solar Energy Research Center (ISC))","","2024","Interdigitated back contact (IBC) architecture can yield among the highest silicon wafer-based solar cell conversion efficiencies. Since both polarities are realized on the rear side, there is a definite need for a patterning step. Some of the common patterning techniques involve photolithography, inkjet patterning, and laser ablation. This work introduces a novel patterning technique for structuring the rear side of IBC solar cells using the enhanced oxidation characteristics under the locally laser-doped n++ back surface field (BSF) regions with high-phosphorous surface concentrations. Phosphosilicate glass layers deposited via POCl3 diffusion serve as a precursor layer for the formation of local heavily laser-doped n++ BSF regions. The laser-doped n++ BSF regions exhibit a 2.6-fold increase in oxide thickness compared to the nonlaser-doped n+ BSF regions after undergoing high-temperature wet thermal oxidation. The utilization of oxide thickness selectivity under laser-doped and nonlaser-doped regions serves two purposes in the context of the IBC solar cell, first patterning rear side and second acting as a masking layer for the subsequent boron diffusion. Proof-of-concept solar cells are fabricated using this novel patterning technique with a mean conversion efficiency of 20.41%.","interdigitated back contact solar cells; laser doping; patterning techniques; SiO as diffusion barriers","en","journal article","","","","","","","","","","","Photovoltaic Materials and Devices","","",""
"uuid:08100443-b972-48cc-9582-ec2478cc247f","http://resolver.tudelft.nl/uuid:08100443-b972-48cc-9582-ec2478cc247f","The impact of modulational instability on coastal wave forecasting using quadratic models","Akrish, G. (TU Delft Environmental Fluid Mechanics); Reniers, A.J.H.M. (TU Delft Environmental Fluid Mechanics); Zijlema, Marcel (TU Delft Environmental Fluid Mechanics); Smit, P.B. (Sofar Ocean Technologies)","","2024","Coastal wave forecasting over large spatial scales is essential for many applications (e.g., coastal safety assessments, coastal management and developments, etc.). This demand explains the necessity for accurate yet effective models. A well-known efficient modelling approach is the quadratic approach (often referred to as frequency-domain models, nonlinear mild-slope models, amplitude models, etc.). The efficiency of this approach stems from a significant modelling reduction of the original governing equations (e.g., Euler equations). Most significantly, the description of wave nonlinearity essentially collapses into a single mode coupling term determined by the quadratic interaction coefficients. As a result, it is expected that the efficiency achieved by the quadratic approach is accompanied by a decrease in prediction accuracy. In order to gain further insight into the predictive capabilities of this modelling approach, this study examines six different quadratic formulations, three of which are of the Boussinesq type and the other three are referred to as fully dispersive. It is found that while the Boussinesq formulations reliably predict the evolution of coastal waves, the predictions by the fully dispersive formulations tend to be affected by false developments of modulational instability. Consequently, the predicted wave fields by the fully dispersive formulations are characterized by unexpectedly strong modulations of the sea-swell part and associated unexpected infragravity response. The impact of the modulational instability on wave prediction based on the quadratic approach is further demonstrated using existing laboratory results of bichromatic and irregular wave conditions.","Modulation instability; Spectral modelling; Quadratic modelling; Coastal waves; Wave nonlinearity; Infragravity waves","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:a22ada54-8856-43e8-a0f0-22d5ec39677a","http://resolver.tudelft.nl/uuid:a22ada54-8856-43e8-a0f0-22d5ec39677a","Explaining Grover's algorithm with a colony of ants: a pedagogical model for making quantum technology comprehensible","Schalkers, M.A. (TU Delft Numerical Analysis); Dankers, K.T. (TU Delft Ethics & Philosophy of Technology; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wimmer, M.T. (TU Delft QN/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Vermaas, P.E. (TU Delft Ethics & Philosophy of Technology)","","2024","The rapid growth of quantum technologies requires an increasing number of physicists, computer scientists, and engineers who can work on these technologies. For educating these professionals, quantum mechanics should stop being perceived as incomprehensible. In this paper we contribute to this change by presenting a pedagogical model for explaining Grover's search algorithm, a prominent quantum algorithm. This model visualizes the three main steps of Grover's algorithm and, in addition to explaining the algorithm itself, introduces three key principles of quantum mechanics: superposition, interference, and state collapse at measurement. The pedagogical model, visualized by a video, is called the ant colony maze model. It represents the search problems as finding the exit of a maze, and visualizes Grover's search algorithm as a strategy by which a colony of ants finds that exit.","","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:546be427-9b8d-497f-8b99-020a30178508","http://resolver.tudelft.nl/uuid:546be427-9b8d-497f-8b99-020a30178508","Rethink the City: New Approaches to Global and Local Urban Challenges","","van der Watt, A. (editor); Vergara d'Alençon, L.M. (editor); Tempels Moreno Pessoa, Igor (editor); Newton, C.E.L. (editor)","2024","In light of rapid urbanisation and the accelerating threats of climate change, scale and multitude are what set the Global North and South apart. Yet, as this course exposes, the issues faced by urban areas have resembling themes and characteristics, regardless of economic status or geographic location. Therefore, in the context of sustainable urban development, the binary dichotomy of the terms ‘Global North’ and ‘Global South’ must be contested. While a focus on Africa, Latin America and the Caribbean, Asia, and the MENA region, Rethink the City attempts to understand the transboundary nature of urban issues and provide a platform to gather insights beyond borders. It is only by learning from other narratives that we can collectively address the complex challenges ahead.","Global South; urban development; spatial justice; resilience; e-learning","en","book","TU Delft OPEN","978-94-6366-800-2","","","","","","","","","Real Estate Management","","",""
"uuid:5801ae5f-f603-4e16-9ec0-1bca9c0f06f1","http://resolver.tudelft.nl/uuid:5801ae5f-f603-4e16-9ec0-1bca9c0f06f1","Whitepaper: De onzekerheden bij de aanleg van een warmtenet met datathermie in transformatiegebied","Franchimon, Francesco (Amsterdam Institute for Advanced Metropolitan Solutions (AMS)); Koning, Kyra (Amsterdam Institute for Advanced Metropolitan Solutions (AMS)); van der Ham, Jonas (Amsterdam Institute for Advanced Metropolitan Solutions (AMS)); Voskuilen, Paul (Amsterdam Institute for Advanced Metropolitan Solutions (AMS)); Correljé, A. (TU Delft Economics of Technology and Innovation); Ersoy, A. (TU Delft Urban Development Management)","","2024","Voor dit onderzoek is data verzameld door middel van sleuteldocumenten, interviews en enquêtes. Alle stakeholders zijn individueel geïnterviewd in november 2022 middels een semigestructureerd interview. Hierbij zijn sleuteldocumenten gebruikt om de positie van een bepaalde stakeholdersgroep inzake warmtenetten te kennen, zoals positionpapers van brancheverenigingen of beleidsdocumenten.
Uit de interviews met de stakeholders zijn onzekerheden geïdentificeerd. Een samenvatting van de geïdentificeerde onzekerheden is ter verificatie aangeboden aan de geïnterviewde stakeholders. Vanuit alle geïdentificeerde onzekerheden heeft het onderzoeksteam een inschatting gemaakt welke onzekerheden van toepassing konden zijn voor een bepaalde stakeholdersgroep. Hierbij zijn de volgende stakeholdergroepen gedefinieerd: gemeente, warmtebedrijven, warmteproducent en projectontwikkelaars.
Vervolgens hebben stakeholders per enquête geverifieerd of de stakeholdersgroep bloot wordt gesteld aan de voorgelegde onzekerheden. Daarbij wordt er van uitgegaan dat als, bijvoorbeeld, één projectontwikkelaar aangaf dat zij aan een onzekerheid wordt blootgesteld, die onzekerheid van toepassing is op de gehele groep van projectontwikkelaars.
De primaire doelgroep voor dit whitepaper zijn gemeenten, maar ook voor andere stakeholders die betrokken zijn bij de ontwikkeling van een warmtenet zijn er zinvolle lessen te trekken.","beleid; innovatie; data","nl","report","AMS Institute","","","","","","","","","","Urban Development Management","","",""
"uuid:8a7f2545-be14-454e-8cd9-7fe344d9383f","http://resolver.tudelft.nl/uuid:8a7f2545-be14-454e-8cd9-7fe344d9383f","Imaging the magma plumbing system of Ciomadul volcano and the Perşani Volcanic Field and constraining postcollisional magma dynamics","Comeau, M.J. (TU Delft Applied Geophysics and Petrophysics); Hill, Graham J. (Czech Academy of Sciences); Kovacikova, Svetlana (Czech Academy of Sciences); Kamm, Jochen (Geological Survey of Finland); Lukács, Réka (HUN-REN Research Centre for Astronomy and Earth Sciences); Seghedi, Ioan (Academia Română); Grayver, Alexander (Universität zu Köln); Bondár, István (HUN-REN Research Centre for Astronomy and Earth Sciences); Szabolcs, Harangi (Eötvös Loránd University)","","2024","There are indications that some long-dormant or seemingly inactive volcanoes may have potentially active magma storage systems. One such system is Ciomadul volcano, which is located at the south-eastern terminus of the Carpathian volcanic chain (Romania). With the last eruption occurring at ~30 ka, this is the youngest volcano in eastern-central Europe. Understanding the nature and structure of the magma plumbing system is crucial to elucidating the evolution of the volcano and to assessing its hazard potential. This includes the depth, size, and geometry of the magma storage region, the amount and composition of the melt present, and the link between mantle and crustal processes.
Ciomadul is situated in a geodynamically active region about 50 km from the Vrancea zone, where deep earthquakes are frequent. These earthquakes may represent the descent of a dense lithospheric slab beneath a continental collision zone and this may imply an asthenospheric upwelling due to return flow of mantle material. To the north-west of Ciomadul lies a chain of older volcanic complexes, the Călimani–Gurghiu-Harghita volcanic complex; about 40 km west of Ciomadul towards the Transylvanian Basin, a monogenetic basaltic volcanic region was developed at 1.2–0.5 Ma (Perşani volcanic field). Seismic tomography has revealed low-velocity columns through the lithosphere beneath both Ciomadul and Perşani. However, high-resolution images of the complex geometry of the system are lacking.
We report here on a 3-D electrical resistivity model of the region that was generated from 41 magnetotelluric measurements acquired in 2022 that form a 75 km by 75 km array. The data typically had reliable periods from 128 Hz to 4,100+ s. Choosing appropriate locations for measurement was critical, away from sources of cultural electromagnetic noise that can contaminate the signals, as was careful data processing, including applying data pre-selection schemes and manual time windows in addition to standard approaches using robust statistics.
Phase tensor analysis suggests that the data are 3-D at all scales. The 3-D electrical resistivity model reveals conductive anomalies (<10 ohm-m) in the subvolcanic crust. These are interpreted as melt-bearing magma reservoirs distributed in the mid-lower crust (depths of ~10–25 km) and a quasi-vertical conduit extending to the near surface. The crustal reservoir is oriented north-south, has its western margin beneath the surface vent of Ciomadul, and extends ~20 km eastward. These results are consistent with the quantitative petrological models placing the upper melt-bearing silicic crystal mush reservoir at a depth of 5–20 km beneath Ciomadul, and a magma-generation area in the asthenosphere (85–105 km depth). In contrast, no strong conductive anomaly is observed in the crust below Perşani, which fits the magma evolution model, i.e. small batches of mantle-derived magmas ascend rapidly through the crustal column. Our results suggest that Ciomadul, a seemingly inactive volcano, is still underlain by a melt-bearing magma body and therefore can be regarded as having potential for reactivation and further volcanic eruptions.","","en","abstract","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:13c158e0-a6b0-488d-9254-e81f005884ce","http://resolver.tudelft.nl/uuid:13c158e0-a6b0-488d-9254-e81f005884ce","Regional Magnetotelluric Studies across Mongolia: Report on New Measurements, New Models, and Implications for Intracontinental Deformation, Deep Mineral Systems, and Intraplate Volcanism","Rigaud, Rafael (ETH Zürich); Comeau, M.J. (TU Delft Applied Geophysics and Petrophysics); Batmagnai, Erdenechimeg (Mongolian Academy of Sciences); Kruglyakov, Mikhail (University of Otago); Kuvshinov, Alexey (ETH Zürich); Becken, Michael (University of Münster); Tserendug, Shoovdor (Mongolian Academy of Sciences); Demberel, Sodnomsambuu (Mongolian Academy of Sciences)","","2024","We are investigating the lithospheric properties and lithospheric architecture beneath Mongolia with three-dimensional models of the electrical resistivity generated from magnetotelluric measurements. In addition, thermo-mechanical numerical modelling, with geophysically-guided constraints, is being used to provide valuable insights by testing the mechanical viability of different hypotheses for the temporal evolution and dynamic processes within this region.
Mongolia is located between the relatively stable Siberian craton and the extensional regime near the Baikal rift zone to the north and to the south the North China and Tarim cratons that have a northward-directed compressional regime. Due to its location, it is an excellent region to study intracontinental deformation. Furthermore, enigmatic continental intraplate basaltic volcanism of the Cenozoic age exists across Mongolia. In addition, this region contains economically important mineral zones (copper and gold), with the origin and evolution of the mineral systems linked to the whole-lithosphere architecture, crust-mantle interactions, and mantle convection dynamics.
Magnetotelluric data has been collected across Western, Central, and Eastern Mongolia. Three field campaigns in 2016, 2017, and 2018 collected more than 328 sites on an array (50 km spacing) and along three dense profiles (3-15 km spacing) that focused on the Hangai Dome (plateau) and Gobi-Altai (Arkhangai, Bayankhongor) over an area of approximately 800 km (north-south) by 400 km (east-west). Between 2020 and 2022, the array was extended to the east with 77 sites collected across central-east Mongolia (Bulgan, Selenge, Tuv, Uvurkhangai, Dundgovi; 400 by 200 km), including 34 sites along an 810 km long north-south profile crossing the Mongol-Okhotsk suture zone. In late 2022, 79 measurements were acquired in northern Mongolia across the Hovsgol region and Darhad (200 by 200 km) with an array and several profiles, which connect to data west of Lake Baikal. In early 2023, 38 sites were collected in central-east Mongolia (Umnugovi; 200 by 200 km), completing the eastern array. Later in 2023, a major field campaign was launched that successfully collected 150 measurements in western Mongolia (Zavkhan, Uvs, Govi-Altai, Khovd) over an area of approximately 500 by 400 km. This included an array (50 km spacing) and three dense profiles (5-10 km spacing). This gives approximately 700 magnetotelluric measurements collected over a total area of approximately 1000 km (north-south) by more than 1150 km (east-west).
This is a large area that approaches the scope of several other regional and national magnetotelluric survey programs. What’s more, this dataset fills an important gap between the existing magnetotelluric data across China and the Tibetan Plateau with several profiles across the Siberian Craton, in principle completing a remarkable transect of 4000 km across a variety of tectonic domains.
In this presentation, we will report on the new measurements. They will be integrated into the previously collected dataset, and new models will be generated that incorporate all data. We will also present new models of western, central and eastern Mongolia that provide insights on the properties, structure, and evolution of the Hangai Dome, the Mongol-Okhotsk suture and the Central Asian Orogenic Belt.","","en","abstract","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:95eddc8d-202b-4355-81ed-44cde9ed6d7b","http://resolver.tudelft.nl/uuid:95eddc8d-202b-4355-81ed-44cde9ed6d7b","Deep plumbing model of the Cenozoic Manzaz / Atakor intraplate volcanic system, Central Hoggar, Northwest Africa, based on electrical resistivity models","Boukhalfa, Zakaria (Centre de Recherche en Astonomie, Astrophysique et Géophysique; Université des Sciences et Technologie Houari Boumedien); Comeau, M.J. (TU Delft Applied Geophysics and Petrophysics); Benhallou, Amel (Centre de Recherche en Astonomie, Astrophysique et Géophysique); Bouzid, Abderrezak (Centre de Recherche en Astonomie, Astrophysique et Géophysique); Bendaoud, Abderrahmane (Université des Sciences et Technologie Houari Boumedien)","","2024","Continental intraplate volcanic systems, with their location far from plate tectonic boundaries, are not well understood: the crustal and lithospheric mantle structure of these systems remain enigmatic and there is no consensus on the mechanisms that cause melt generation and ascent. The Cenozoic saw the development of numerous volcanic provinces on the African plate. This includes the Hoggar volcanic province, located in Northwest Africa, part of the Tuareg shield. It is composed of several massifs with contrasting ages and eruptive styles. The magmatic activity began at around 34 Ma and continued throughout the Neogene-Quaternary. Phonolite and trachyte domes as well as scoria cones and necks are found in the Manzaz and Atakor volcanic districts. In order to image the crustal and lithospheric mantle structure of this region, and to understand the origins and potential mechanisms of the continental intraplate volcanic activity in the Central Hoggar and specifically the Atakor/Manzaz area, we acquired magnetotelluric (MT) measurements from 40 locations and generated a 3-D electrical resistivity model. The model covers an area of about 100 km by 200 km. Images of the subsurface architecture, in terms of electrical resistivity, from the near-surface to the lithospheric mantle, allow us image the deep plumbing system of the volcanic system. Low resistivity features (i.e., conductors) in the crust that are narrow, linear structures trending approximately north-south, are revealed along the two boundaries of the Azrou N’Fad terrane, in the Manzaz area. They likely reflect the Pan-African mega-shear zones, which were reactivated throughout the tectonic evolution of the region. The model reveals that these faults are lithospheric-scale. In addition, the low-resistivity features likely represent the signatures of past fluid flow. The location of the recent Cenozoic volcanic activity was likely influenced by the pre-existing structure. A deep feature of moderate conductivity is located in the upper lithospheric mantle directly beneath the Manzaz and Atakor Volcanic Districts. It may represent the origin of the overlying anomalies and may suggest metasomatism of the sub-continental lithospheric mantle.","intraplate; Hoggar; alkaline volcanism; magnetotelluric; electrical resistivity","en","abstract","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:9a9ddc99-8f12-46d0-9065-125126230efc","http://resolver.tudelft.nl/uuid:9a9ddc99-8f12-46d0-9065-125126230efc","Transformatie naar Woningen","","Remøy, H.T. (editor); van Bortel, G.A. (editor); Heurkens, E.W.T.M. (editor); van Venrooij, R.G.A.M. (editor)","2024","Om het woningtekort op te lossen moeten er jaarlijks zo’n 90.000 nieuwbouwwoningen aan het woningbestand worden toegevoegd. Transformatie van leegstaande gebouwen en herbestemming naar woningen draagt bij aan de oplossing hiervoor. Transformatie werd tot rond 2014 gezien als een oplossing voor de leegstand op de kantorenmarkt, die in de periode 2001–2013 hoog opliep, landelijk van rond 5% in 2001 tot bijna 15% in 2013. De hoge leegstand was mede het gevolg van de dotcom-crisis en de financiële crisis, die samen met technologische ontwikkelingen en een toename in flexwerken leidden tot minder benodigde vierkante meters kantoren, terwijl er juist een overschot aan kantoren werd ontwikkeld en gebouwd.
Rond 2014 is een kantelpunt zichtbaar geworden. Transformatie werd steeds vaker gemotiveerd door de vraagzijde van de woningmarkt en niet meer door de aanbodzijde van de kantorenmarkt. De aandacht voor duurzaam bouwen en het verduurzamen van de bestaande gebouwenvoorraad nam toe. In het boek Transformatie van kantoorgebouwen uit 2007 werd duurzaamheid nauwelijks genoemd. Hooguit werd transformatie vermeld als intrinsiek duurzaam, omdat het gebouw werd hergebruikt. Door toegenomen energiekosten en kosten van bouwmaterialen, en door de klimaatcrisis zijn duurzaamheidsaspecten zoals energie-efficiënt, circulair en aanpasbaar bouwen echter veel belangrijker geworden, hoewel ze nog niet overal worden toegepast.
Nederland kent een grote vraag naar woningen, maar daarnaast staan veel gebouwen leeg. Op veel plekken in de Randstad staan verouderde kantoorgebouwen waar geen vraag meer naar is. In het hele land komen kerken leeg te staan door vergrijzing en ontkerkelijking. Door verplaatsing van industrie uit de binnensteden naar beter bereikbare locaties of naar het buitenland verliest industrieel vastgoed zijn functie. Schoolgebouwen komen leeg te staan door vergrijzing van de buurt. Ziekenhuizen komen leeg te staan door de invoering van nieuwe zorgconcepten en schaalvergroting. Veel winkels komen leeg te staan door centralisatie en online winkelen. Gebouwen oorspronkelijk gebouwd voor deze (en andere) functies kunnen worden getransformeerd naar woningen.
Versmelting van oud en nieuw draagt bij aan behoud van identiteit. Wanneer ook nog eens sprake is van architectonisch interessante gebouwen draagt transformatie bij aan behoud van het cultureel erfgoed. Transformatie kan bijdragen aan verduurzaming van de gebouwenvoorraad en het reduceren van grondstoffengebruik en sloopafval. Transformatie zou jaarlijks 10-15% van de woningproductie kunnen bijdragen.","Housing; Transformation","nl","book","Bouwkunde TU Delft","978-94-6366-838-5","","","","","","","","","Real Estate Management","","",""
"uuid:eba16e28-6041-4507-9cc4-ef553496bbea","http://resolver.tudelft.nl/uuid:eba16e28-6041-4507-9cc4-ef553496bbea","Digital Infrastructures for Compliance Monitoring of Circular Economy: Requirements for Interoperable Data Spaces","Hofman, Wout (TNO); Rukanova, B.D. (TU Delft Innovation Affairs); Tan, Y. (TU Delft Information and Communication Technology); Bharosa, Nitesh (TU Delft Information and Communication Technology); Ubacht, J. (TU Delft Information and Communication Technology); Rietveld, Elmer (TNO)","Arai, Kohei (editor)","2024","The transition towards a circular economy (CE) will require data sharing across different platforms and data spaces of parties operating in a variety of supply chains. From a circular economy compliance monitoring perspective, beyond the access to mandatory data that governments will receive, authorities may benefit from accessing additional business data from the source on a voluntary basis, which is challenging. While platforms and data spaces solve a great deal of complexity and interoperability within their realm, platform, and data space interoperability is still challenging. In the logistics domain, efforts have been made to overcome these issues of data sharing across logistics platforms with a Semantic data sharing architecture developed by the CEF FEDeRATED Action, at the heart of which is a semantic model aligning other semantic models for logistics. In this paper, we take the Semantic data sharing architecture as a point of departure and examine the opportunities and limitations that it has for CE monitoring, and how it relates to other developments in the EU and beyond. Many of these developments acknowledge the need for data access across heterogeneous systems and – processes of actors; others add security and trust to data sharing that goes all the way to the level to cover legal obligations. The goal of this paper is to gain further insights into how data sharing across multiple platforms and data spaces enables circular economy monitoring, where government organizations would need to address the issue of how they would interface with, and access data that resides in multiple platforms and data spaces. We found that the various models can be aligned on some architecture principles that promote interoperability across dimensions (e.g. federation, keeping data at the source), yet they still differ on other dimensions (e.g. data model and semantics, as well as how they address issues of identification, authentication and authorization). We suggest further efforts towards developing meta-level agreements and standardization for data space interoperability and we propose further research directions on that topic.","Data spaces; Platforms; Interoperability; Circular economy; Monitoring; Government","en","book chapter","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-17","","","Innovation Affairs","","",""
"uuid:71253e50-4533-4855-a284-793ddac88c00","http://resolver.tudelft.nl/uuid:71253e50-4533-4855-a284-793ddac88c00","Six smart guidelines for high-tech manufacture on low-tech 3D printers: the case of the 3Flex","Trauzettel, F. (TU Delft Medical Instruments & Bio-Inspired Technology; Katholieke Universiteit Leuven); Vander Poorten, Emmanuel (Katholieke Universiteit Leuven); Ourak, Mouloud (Katholieke Universiteit Leuven); Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology); Breedveld, P. (TU Delft Medical Instruments & Bio-Inspired Technology)","","2024","While articulated surgical instruments have enabled the proliferation of minimally invasive interventions, procedures such as laparo-endoscopic single-site surgery are waning in popularity. One potential reason for this decline is a lack of sufficiently dexterous instruments. Although multi-steerable instruments exist, these are often complex and therefore expensive assemblies. Even when 3D printing was used to simplify the design of these instruments, the requirement for high-performance 3D printers limited the reduction in manufacturing costs. To tackle this issue, we propose six guidelines for converting a 3D printed compliant medical instrument from printing on a Digital Light Processing (DLP) printer to a Fused Filament Fabrication (FFF) printer. These guidelines provide a framework to manage and compensate for differences in the two processes to achieve comparable results at a reduced cost. The proposed guidelines were evaluated by assembling a FFF 3D printed prototype that shows equivalent performance to its DLP 3D printed counterpart.","3D printing; Hyper-redundant; medical devices; snake-like; surgical instruments","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:77a4b20a-6094-4093-a5a6-f946f93da5b9","http://resolver.tudelft.nl/uuid:77a4b20a-6094-4093-a5a6-f946f93da5b9","Buckling failure analysis of storage tanks under the synergistic effects of fire and wind loads","Chen, Chao (Southwest Petroleum University; China Academy of Safety Science and Technology); Chen, Hang (Southwest Petroleum University); Mo, Li (Southwest Petroleum University); Xiao, Shenbin (Southwest Petroleum University); Li, Changjun (Southwest Petroleum University); Yang, M. (TU Delft Safety and Security Science); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven)","","2024","Fire-induced domino effect is one of the main threats to hazardous material storage tanks, and many attempts have been conducted to assess the vulnerability of storage tanks exposed to fire to evaluate domino effect risk. However, past research ignored the influence of wind load on the thermal buckling behavior of storage tanks exposed to fire, which may underestimate the risk of exposed tanks. This paper thus conducts a numerical simulation of the thermal buckling behavior of steel vertical dome storage tanks under the synergistic effect of static wind loads and thermal effects. The effects of wind parameters and heat radiation parameters on the thermal post-buckling behavior and the time to failure (ttf) of storage tanks are investigated to analyze the synergistic effects of fire and wind loads. By comparing the circumferential and meridional stresses before and after the thermal post-buckling stage, it is found that under the disturbing effect of the positive wind pressure load, the thermal post-buckling of the tanks on downwind occurs earlier and more severe. Besides, the effects of wind angle, fire location height, and diameter on buckling damage were investigated. The comparative analysis of different scenarios shows that the tanks in the windy scenario are more prone to thermal post-buckling, and the deformation is intensified, with an increased likelihood of failure.","Domino effects; Numerical simulation; Storage tank; Thermal post-buckling; Wind load","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-04","","","Safety and Security Science","","",""
"uuid:57847760-f408-4c02-a96b-a5aa43b81648","http://resolver.tudelft.nl/uuid:57847760-f408-4c02-a96b-a5aa43b81648","Investigating Mechanical Properties of Silicon Carbide Coated Carbon Nanotube Composite at Elevated Temperatures","Mo, J. (TU Delft Electronic Components, Technology and Materials); Schaffar, Gerald J.K. (Montanuniversität Leoben); Du, L. (TU Delft Electronic Components, Technology and Materials); Maier-Kiener, Verena (Montanuniversität Leoben); Kiener, Daniel (Montanuniversität Leoben); Vollebregt, S. (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2024","Silicon carbide (SiC) coated vertically aligned carbon nanotubes (VACNT) are attractive material for fabricating MEMS devices as an alternative for bulk micromachining of SiC. In order to examine the mechanical properties of SiC-CNT composites at high temperatures, we fabricated VACNT micro-pillars with different amounts of SiC coating and performed high-temperature micro-pillar compression on these samples. The indentation result shows that the coating can improve the elastic modulus up to three orders of magnitude. Samples were tested at room temperature, 300°C, 600°C, and 900°C under compressive load. No significant degradation of the mechanical properties was observed at elevated temperatures, demonstrating the harsh environment potential of this composite.","SiC-CNT composite; high-temperature; micro-pillar; compression test","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-22","","","Electronic Components, Technology and Materials","","",""
"uuid:f515445b-f3a8-491e-9cf1-8cd3425455a8","http://resolver.tudelft.nl/uuid:f515445b-f3a8-491e-9cf1-8cd3425455a8","A DfT Strategy for Guaranteeing ReRAM’s Quality after Manufacturing","Copetti, T. S. (Rheinisch-Westfälische Technische Hochschule); Fieback, M. (TU Delft Computer Engineering); Gemmeke, T. (Rheinisch-Westfälische Technische Hochschule); Hamdioui, S. (TU Delft Computer Engineering); Poehls, L. M.Bolzani (Rheinisch-Westfälische Technische Hochschule)","","2024","Memristive devices have become promising candidates to complement the CMOS technology, due to their CMOS manufacturing process compatibility, zero standby power consumption, high scalability, as well as their capability to implement high-density memories and new computing paradigms. Despite these advantages, memristive devices are susceptible to manufacturing defects that may cause faulty behaviors not observed in CMOS technology, significantly increasing the challenge of testing these novel devices after manufacturing. This work proposes an optimized Design-for-Testability (DfT) strategy based on the introduction of a DfT circuitry that measures the current consumption of Resistive Random Access Memory (ReRAM) cells to detect not only traditional but also unique faults. The new DfT circuitry was validated using a case study composed of a 3x3 word-based ReRAM with peripheral circuitry implemented based on a 130 nm Predictive Technology Model (PTM) library. The obtained results demonstrate the fault detection capability of the proposed strategy with respect to traditional and unique faults. In addition, this paper evaluates the impact related to the DfT circuitry’s introduced overheads as well as the impact of process variation on the resolution of the proposed DfT circuitry.","DfT Circuitry; Manufacturing test; ReRAMs; Unique faults","en","journal article","","","","","","","","","","","Computer Engineering","","",""
"uuid:26c82303-0b72-4b8f-961c-40a5cfe9540a","http://resolver.tudelft.nl/uuid:26c82303-0b72-4b8f-961c-40a5cfe9540a","A quantitative comparison between the mHand Adapt passive adjustable hand prosthesis and its predecessor, the Delft Self-Grasping Hand","Krinis, S.L.L. (Student TU Delft; University of Salford); Chadwell, Alix (University of Salford); Kenney, Laurence (University of Salford); Smit, G. (TU Delft Medical Instruments & Bio-Inspired Technology)","","2024","Introduction
The Delft Self-Grasping Hand (SGH) is an adjustable passive hand prosthesis that relies on wrist flexion to adjust the aperture of its grasp. The mechanism requires engagement of the contralateral hand meaning that hand is not available for other tasks. A commercialised version of this prosthesis, known as the mHand Adapt, includes a new release mechanism, which avoids the need to press a release button, and changes to the hand shape. This study is the first of its kind to compare two passive adjustable hand prostheses on the basis of quantitative scoring and contralateral hand involvement.
Methods
10 anatomically intact participants were asked to perform the Southampton Hand Assessment Procedure (SHAP) with the mHand. Functionality and contralateral hand involvement were recorded and compared against SGH data originating from a previous trial involving a nearly identical testing regime.
Results
mHand exhibited higher functionality scores and less contralateral hand interaction time, especially during release-aiding interactions. Additionally, a wider range of tasks could be completed using the mHand than the SGH.
Discussion
Geometric changes make the mHand more capable of manipulating smaller objects. The altered locking mechanism means some tasks can be performed without any contralateral hand involvement and a higher number of tasks do not require contralateral involvement when releasing. Some participants struggled with achieving a good initial grip due to the inability to tighten the grasp once already formed.
Conclusion
The mHand offers the user higher functionality scores with less contralateral hand interaction time and the ability to perform a wider range of tasks. However, there are some design trade-offs which may make it slightly harder to learn to use.
2 or formate can also serve as additional electron donors for sulfur reduction, while nitrate can be ammonified with either sulfide or formate as the electron donors. The cultured representatives are found exclusively in saline soda lakes. The family consists of a single genus Desulfurivibrio with the type species D. alkaliphilus and a second yet undescribed species “D. dismutans” DNA G+C content (%): 60.0-60.3 (whole genome sequences)
Type genus : Desulfurivibrio Sorokin et al. 2008, VL123
2/Si substrates, while the intensity was reduced to 60 % and 80 % with ~10 nm and ~16 nm hBN thicknesses respectively. We confirm that pre-determined hBN thicknesses can be employed to control the non-radiative energy transfer properties of graphene, with fluorescence quenching following a d−4 distance-dependent behaviour. This seamless integration of electronically active and dielectric van der Waals materials into vertical heterostructures enables multifunctional platforms addressing the manipulation, localization, and visualization of biomolecules for fundamental biophysics and biosensing applications.","fluorescence; graphene; hexagonal boron nitride (hBN); lipids; quenching","en","journal article","","","","","","D.H.S. and S.C. acknowledge funding from the European Union's Horizon 2020 research and innovation program (ERC StG, SIMPHONICS, Project No. 101041486). S.C. acknowledges a Delft Technology Fellowship. X.Y. acknowledges funding from the Chinese Scholarship Council (Scholarship No. 202108270002). Z.Y. acknowledges funding from NWO (Project MechanoPore).","","","","","Dynamics of Micro and Nano Systems","","",""
"uuid:26963a15-8dc6-49ce-9ffb-2136afd8bd0f","http://resolver.tudelft.nl/uuid:26963a15-8dc6-49ce-9ffb-2136afd8bd0f","State-of-the-practice in quality assurance in Java-based open source software development","Khatami, Ali (TU Delft Software Engineering); Zaidman, A.E. (TU Delft Software Technology)","","2024","To ensure the quality of software systems, software engineers can make use of a variety of quality assurance approaches, for example, software testing, modern code review, automated static analysis, and build automation. Each of these quality assurance practices have been studied in depth in isolation, but there is a clear knowledge gap when it comes to our understanding of how these approaches are being used in conjunction, or not. In our study, we broadly investigate whether and how these quality assurance approaches are being used in conjunction in the development of 1454 popular open source software projects on GitHub. Our study indicates that typically projects do not follow all quality assurance practices together with high intensity. In fact, we only observe weak correlation among some quality assurance practices. In general, our study provides a deeper understanding of how existing quality assurance approaches are currently being used in Java-based open source software development. Besides, we specifically zoom in on the more mature projects in our dataset, and generally we observe that more mature projects are more intense in their application of the quality assurance practices, with more focus on their ASAT usage, and code reviewing, but no strong change in their CI usage.","automated static analysis; build automation; code review; continuous integration; software quality assurance; software testing","en","journal article","","","","","","","","","","Software Technology","Software Engineering","","",""
"uuid:79945b43-4d28-436a-9199-a332782f3cc4","http://resolver.tudelft.nl/uuid:79945b43-4d28-436a-9199-a332782f3cc4","Indoor localisation through Isovist fingerprinting from point clouds and floor plans","Triantafyllou, Georgios (Student TU Delft); Verbree, E. (TU Delft Digital Technologies); Rafiee, A. (TU Delft Digital Technologies)","","2024","The objective of this paper is to investigate and propose a method for Indoor Localisation based on Isovists, with the aim of extending the fields of Location-based Services and Geomatics. Various methods and combinations incorporating Isovist concepts, Space Syntax, and visibility graphs are examined and assessed. By investigating these approaches, this study aims to create a comprehensive methodology to achieve localisation using Isovists. The main conclusion drawn from this research is that an Indoor Localisation method based on Isovists is not only feasible but can also effectively support Location-based Services. The analysis and evaluation of all the components have been thoroughly conducted, indicating that when properly integrated, they can provide substantial value for LBS applications. As this is a new method for Indoor Localisation, there is significant scope for future work, particularly in terms of connecting it with existing techniques and integrating them into user applications.","indoor localisation; space syntax; isovists; fingerprinting; point clouds","en","journal article","","","","","","","","","","","Digital Technologies","","",""
"uuid:20ff96ee-8198-4c41-b6ad-9cddfb83d77e","http://resolver.tudelft.nl/uuid:20ff96ee-8198-4c41-b6ad-9cddfb83d77e","New approximations for network reliability","Brown, Jason I. (Dalhousie University); Kolokolnikov, Theodore (Dalhousie University); Kooij, Robert (TU Delft Quantum & Computer Engineering; TNO)","","2024","We introduce two new methods for approximating the all-terminal reliability of undirected graphs. First, we introduce an edge removal process: remove edges at random, one at a time, until the graph becomes disconnected. We show that the expected number of edges thus removed is equal to (Formula presented.), where (Formula presented.) is the number of edges in the graph, and (Formula presented.) is the average of the all-terminal reliability polynomial. Based on this process, we propose a Monte-Carlo algorithm to quickly estimate the graph reliability (whose exact computation is NP-hard). Moreover, we show that the distribution of the edge removal process can be used to quickly approximate the reliability polynomial. We then propose increasingly accurate asymptotics for graph reliability based solely on degree distributions of the graph. These asymptotics are tested against several real-world networks and are shown to be accurate for sufficiently dense graphs. While the approach starts to fail for “subway-like” networks that contain many paths of vertices of degree two, different asymptotics are derived for such networks.","approximation; average reliability; first order approximation; Monte Carlo; network reliability; regular graph; second order approximation; subway-like network","en","journal article","","","","","","","","","","Quantum & Computer Engineering","","","",""
"uuid:f138b367-2840-447d-8d8d-436147df4061","http://resolver.tudelft.nl/uuid:f138b367-2840-447d-8d8d-436147df4061","On the design of 5GDHC substation control systems","Khlebnikova, E. (TU Delft Sanitary Engineering); Pothof, I.W.M. (TU Delft Sanitary Engineering; Deltares); van der Zwan, Sam (Deltares); Loverdou, Lefki (Gemeente Rotterdam)","","2024","This paper presents challenges in the control of 5GDHC networks and proposes an approach for the robust control design of these networks. Temperatures are low and temperature differences are small in 5GDHC networks, in order to minimise heat losses in the distribution network and directly utilise low-temperature heat sources. Therefore, the robust control design of substations is crucial for stable and efficient operation of 5GDHC networks. We proposed the key steps to obtain a consistent control design that can be verified and tested prior to commissioning of the building substations and network. The design approach was elaborated in a case study in an existing neighbourhood in Haarlem, the Netherlands, constructed in the 1930s to 1970s. This neighbourhood will become independent of natural gas using PVT-rooftop panels, individual heat pumps (HP), a 2-pipe, bi-directional energy flow network operating at ultra-low temperatures and ATES system as a seasonal and daily storage facility.","ATES; heat losses; Networks; photovoltaic thermal panels; PI control; WANDA","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:6ae9a117-b801-4cc0-ad21-92b63c258334","http://resolver.tudelft.nl/uuid:6ae9a117-b801-4cc0-ad21-92b63c258334","Analytical mass transfer coefficients for natural convection from vertical gas-evolving electrodes","Valle Marchante, N. (TU Delft Ship Hydromechanics and Structures); Haverkort, J.W. (TU Delft Energy Technology)","","2024","The high mass transfer to or from gas-evolving electrodes is an attractive feature of electrochemical reactors, which can be partly attributed to the large convective flows that arise due to the buoyancy of bubbles. We derive exact analytical expressions for mass transfer coefficients for the case of constant gas flux boundary conditions. For the mass transport both Dirichlet and Neumann boundary conditions are considered. We deploy a recently derived self-similar solution of laminar two-phase flows, with density, hydrodynamic diffusivity, and viscosity dependent on the local gas fraction. Combining this with the Lévêque approximation, new mass transfer coefficients are obtained analytically. These new results are relevant for various electrochemical processes with gas evolution as well as boiling. The new formulation shows the mass transfer coefficient to scale with the vertical coordinate z proportional to z−1/5 for short electrodes and low current densities and z−4/15 for long ones and high current densities. The former limit also applies when buoyancy is due to temperature or concentration differences in the case that density differences are small. We provide a general overview considering all possible gas and mass boundary conditions combinations and a comparison with the Boussinesq approximation of small density differences.","","en","journal article","","","","","","We acknowledge the Dutch Research Council (NWO) for funding under grant agreement KICH1.ED04.20.011 .","","","","","Ship Hydromechanics and Structures","","",""
"uuid:66023eb8-1b30-4150-9338-4ce268205868","http://resolver.tudelft.nl/uuid:66023eb8-1b30-4150-9338-4ce268205868","Quasi In-Situ Study of Microstructure in a Laser Powder Bed Fusion Martensitic Stainless Steel","Shahriari, Ayda (University of New Brunswick); Sanjari, Mehdi (University of New Brunswick; Natural Resources Canada); Mahmoudiniya, Mahdi (Universiteit Gent); Pirgazi, Hadi (Universiteit Gent); Shalchi Amirkhiz, Babak (University of New Brunswick; Natural Resources Canada); Kestens, L.A.I. (TU Delft Team Maria Santofimia Navarro; Universiteit Gent); Mohammadi, Mohsen (University of New Brunswick)","","2024","This study explores the evolution of solidification microstructure of a laser powder bed fusion (L-PBF) martensitic stainless steel during solution annealing and aging. Quasi in-situ experiments using electron backscatter diffraction (EBSD) revealed that the finer, more equiaxed microstructure below the melt pool was susceptible to recrystallization and grain growth during solution annealing. The two distinct solidification microstructures below and inside the melt pool converged into a uniform grain morphology after solution annealing and aging processes. Graphical Abstract: (Figure presented.)","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-09","","","Team Maria Santofimia Navarro","","",""
"uuid:b11cc3e4-6e23-4a88-9d5b-ec02f52a3a20","http://resolver.tudelft.nl/uuid:b11cc3e4-6e23-4a88-9d5b-ec02f52a3a20","Martingale solutions to the stochastic thin-film equation in two dimensions","Sauerbrey, M. (TU Delft Analysis)","","2024","We construct solutions to the stochastic thin-film equation with quadratic mobility and Stratonovich gradient noise in the physically relevant dimension d = 2 and allow in particular for solutions with non-full support. The construction relies on a Trotter–Kato time-splitting scheme, which was recently employed in d = 1. The additional analytical challenges due to the higher spatial dimension are overcome using α-entropy estimates and corresponding tightness arguments.","Noise; Stochastic compactness method; Thin-film equation; α-Entropy estimates","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-01","","","Analysis","","",""
"uuid:ea9543e3-3444-4782-b40c-55eb3c208ac7","http://resolver.tudelft.nl/uuid:ea9543e3-3444-4782-b40c-55eb3c208ac7","Natranaerovirga","Sorokin, Dimitry Y. (TU Delft BT/Environmental Biotechnology; Russian Academy of Sciences); Merkerl, Alexander Y. (Russian Academy of Sciences)","Whitman, William (editor)","2024","The genus Natranaerovirga is a member of the class Clostridia. It includes obligately anaerobic, fermentative heterotrophs which whose key metabolic property is the ability to utilizes polygalacturonates as growth substrates. The species of the genus are highly salt-tolerant, chloride-independent, obligate alkaliphiles found in saline soda lakes and soils in Central Asia. The genus currently includes two species: N. pectinivora, the type species of the genus, and N. hydrolytica. The DNA G+C content is 31.3-32.3 % (whole genome sequences).","","en","book chapter","John Wiley & Sons","","","","","","Campus only","","","","BT/Environmental Biotechnology","","",""
"uuid:428d8733-e8e6-42fc-a42d-caa303e146fa","http://resolver.tudelft.nl/uuid:428d8733-e8e6-42fc-a42d-caa303e146fa","Natranaerovirgaceae","Sorokin, Dimitry Y. (TU Delft BT/Environmental Biotechnology; Russian Academy of Sciences); Merkel, Alexander Y. (Russian Academy of Sciences)","Whitman, William (editor)","2024","Natr.an.aer.o.vir.ga’ce.ae N.L. fem. n. Natranaerovirga, the type genus of the family, -aceae ending to denote a family; N.L. fem. pl. n. Natranaerovirgaceae, the Natranaerovirga family. The family Natranaerovirgaceae includes obligately
anaerobic fermentative bacteria from soda lakes. They are highly salt-tolerant alkaliphiles utilizing carbohydrates as energy and carbon source. The family belongs to the order “Lachnospirales,” class Clostridia, and consists of a single genus Natranaerovirga. The family-level status was established by phylogenomic
analysis based on the Genome Taxonomy Database classification (GDTB).
DNA G +C content (mol%): 31.3–32.3 (whole-genome sequence).
Type genus: Natranaerovirga Sorokin et al. 2012, VL145.
The construction sector in the European Union is, however, the highest producer of waste when compared to other economic sectors, accounting for 35% of the total waste generated (Eurostat, 2018). At the same time the creation, running, maintenance, and refurbishment of buildings are highly resource and energy intensive. Up to 50% of globally extracted resources are used to construct buildings and associated infrastructures (UNEP, 2020). Greenhouse gas (GHG) emissions from material extraction, manufacturing of construction products, construction, and renovation of buildings are estimated at 5–12% of total national GHG emissions. Construction and demolition material (CDM) efficiency and construction and demolition waste (CDW) prevention could significantly reduce those emissions.","","en","book chapter","Elsevier","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-12","","","Environmental & Climate Design","","",""
"uuid:7df8dacb-3cff-474c-b1bc-cfed9f6ef3bb","http://resolver.tudelft.nl/uuid:7df8dacb-3cff-474c-b1bc-cfed9f6ef3bb","Contrast-Agnostic Groupwise Registration by Robust PCA for Quantitative Cardiac MRI","Li, Xinqi (Student TU Delft); Zhang, Y. (TU Delft ImPhys/Tao group); Zhao, Y. (TU Delft ImPhys/Tao group); van Gemert, J.C. (TU Delft Pattern Recognition and Bioinformatics); Tao, Q. (TU Delft ImPhys/Tao group)","Camara, Oscar (editor); Puyol-Antón, Esther (editor); Suinesiaputra, Avan (editor); Young, Alistair (editor); Sermesant, Maxime (editor); Tao, Qian (editor); Wang, Chengyan (editor)","2024","Quantitative cardiac magnetic resonance imaging (MRI) is an increasingly important diagnostic tool for cardiovascular diseases. Yet, co-registration of all baseline images within the quantitative MRI sequence is essential for the accuracy and precision of quantitative maps. However, co-registering all baseline images from a quantitative cardiac MRI sequence remains a nontrivial task because of the simultaneous changes in intensity and contrast, in combination with cardiac and respiratory motion. To address the challenge, we propose a novel motion correction framework based on robust principle component analysis (rPCA) that decomposes quantitative cardiac MRI into low-rank and sparse components, and we integrate the groupwise CNN-based registration backbone within the rPCA framework. The low-rank component of rPCA corresponds to the quantitative mapping (i.e. limited degree of freedom in variation), while the sparse component corresponds to the residual motion, making it easier to formulate and solve the groupwise registration problem. We evaluated our proposed method on cardiac T1 mapping by the modified Look-Locker inversion recovery (MOLLI) sequence, both before and after the Gadolinium contrast agent administration. Our experiments showed that our method effectively improved registration performance over baseline methods without introducing rPCA, and reduced quantitative mapping error in both in-domain (pre-contrast MOLLI) and out-of-domain (post-contrast MOLLI) inference. The proposed rPCA framework is generic and can be integrated with other registration backbones.","Groupwise registration; motion correction; Quantitative MRI; Robust PCA","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-02","","","ImPhys/Tao group","","",""
"uuid:6b392146-03b6-41b8-9c04-0a9ba0e0103a","http://resolver.tudelft.nl/uuid:6b392146-03b6-41b8-9c04-0a9ba0e0103a","Decoding Individual and Shared Experiences of Media Perception Using CNN Architectures","Johri, Riddhi (Indian Institute of Technology Gandhinagar); Pandey, Pankaj (Indian Institute of Technology Gandhinagar); Miyapuram, Krishna Prasad (Indian Institute of Technology Gandhinagar); Lomas, J.D. (TU Delft Design Aesthetics)","Waiter, Gordon (editor); Leontidis, Georgios (editor); Morris, Teresa (editor); Lambrou, Tryphon (editor); Oren, Nir (editor); Gordon, Sharon (editor)","2024","The brain is an incredibly complex organ capable of perceiving and interpreting a wide range of stimuli. Depending on individual brain chemistry and wiring, different people decipher the same stimuli differently, conditioned by their life experiences and environment. This study’s objective is to decode how the CNN models capture and learn these differences and similarities in brain waves using three publicly available EEG datasets. While being exposed to a variety of media stimuli, each brain produces unique brain waves with some similarity to other neural signals to the same stimuli. However, to figure out whether our neural models are able to interpret and distinguish the common and unique signals correctly, we employed three widely used CNN architectures to interpret brain signals. We extracted the pre-processed versions of the EEG data and identified the dependency of time windows on feature learning for song and movie classification tasks, along with analyzing the performance of models on each dataset. While the minimum length snippet of 5 s was enough for the personalized model, the maximum length snippet of 30 s proved to be the most efficient in the case of the generalized model. The usage of a deeper architecture, i.e., DeepConvNet was found to be the best for extracting personalized and generalized features with the NMED-T and SEED datasets. However, EEGNet gave a better performance on the NMED-H dataset. Maximum accuracy of 69%, 100%, and 56% was achieved in the case of the personalized model on NMED-T, NMED-H, and SEED datasets, respectively. However, the maximum accuracies dropped to 18%, 37%, and 14% on NMED-T, NMED-H, and SEED datasets, respectively, in the generalized model. We achieved a 5% improvement over the state of the art while examining shared experiences on NMED-T. This marked the outof-distribution generalization problem and signified the role of individual differences in media perception, thus emphasizing the development of personalized models along with generalized models with shared features at a certain level.","EEG; Music and Movie perception; Neural responses; Subjective differences","en","conference paper","Springer","","","","","","","2024-06-02","","","Design Aesthetics","","",""
"uuid:e8654a0b-70ad-4eb7-b476-effd3c809477","http://resolver.tudelft.nl/uuid:e8654a0b-70ad-4eb7-b476-effd3c809477","MRHF: Multi-stage Retrieval and Hierarchical Fusion for Textbook Question Answering","Zhu, P. (TU Delft Web Information Systems); Wang, Zhen (Tokyo Institute of Technology); Okumura, Manabu (Tokyo Institute of Technology); Yang, J. (TU Delft Web Information Systems)","Rudinac, Stevan (editor); Worring, Marcel (editor); Liem, Cynthia (editor); Hanjalic, Alan (editor); Jónsson, Björn Pór (editor); Yamakata, Yoko (editor); Liu, Bei (editor)","2024","Textbook question answering is challenging as it aims to automatically answer various questions on textbook lessons with long text and complex diagrams, requiring reasoning across modalities. In this work, we propose MRHF, a novel framework that incorporates dense passage re-ranking and the mixture-of-experts architecture for TQA. MRHF proposes a novel query augmentation method for diagram questions and then adopts multi-stage dense passage re-ranking with large pretrained retrievers for retrieving paragraph-level contexts. Then it employs a unified question solver to process different types of text questions. Considering the rich blobs and relation knowledge contained in diagrams, we propose to perform multimodal feature fusion over the retrieved context and the heterogeneous diagram features. Furthermore, we introduce the mixture-of-experts architecture to solve the diagram questions to learn from both the rich text context and the complex diagrams and mitigate the possible negative effects between features of the two modalities. We test the framework on the CK12-TQA benchmark dataset, and the results show that MRHF outperforms the state-of-the-art results in all types of questions. The ablation and case study also demonstrates the effectiveness of each component of the framework.","Information Retrieval; Mixture-of-Experts; Textbook Question Answering","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Web Information Systems","","",""
"uuid:c755c2bd-92d8-499c-94e6-fc01e14aa7d6","http://resolver.tudelft.nl/uuid:c755c2bd-92d8-499c-94e6-fc01e14aa7d6","Influential Node Detection on Graph on Event Sequence","Lu, Zehao (Universiteit Utrecht); Wang, Shihan (Universiteit Utrecht); Ren, Xiao Long (University of Electronic Science and Technology of China); Costas, Rodrigo (Universiteit Leiden); Metze, T.A.P. (TU Delft Organisation & Governance)","Cherifi, Hocine (editor); Rocha, Luis M. (editor); Cherifi, Chantal (editor); Donduran, Murat (editor)","2024","Numerous research efforts have centered on identifying the most influential players in networked social systems. This problem is immensely crucial in the research of complex networks. Most existing techniques either model social dynamics on static networks only and ignore the underlying time-serial nature or model the social interactions as temporal edges without considering the influential relationship between them. In this paper, we propose a novel perspective of modeling social interaction data as the graph on event sequence, as well as the Soft K-Shell algorithm that analyzes not only the network’s local and global structural aspects, but also the underlying spreading dynamics. The extensive experiments validated the efficiency and feasibility of our method in various social networks from real world data. To the best of our knowledge, this work is the first of its kind.","Dynamics of Network; Influential Node Detection; Non-epidemic Spreading","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-21","","","Organisation & Governance","","",""
"uuid:fa00f697-cf80-4fd9-945e-77080f85ea51","http://resolver.tudelft.nl/uuid:fa00f697-cf80-4fd9-945e-77080f85ea51","Relaxometry Guided Quantitative Cardiac Magnetic Resonance Image Reconstruction","Zhao, Y. (TU Delft ImPhys/Tao group); Zhang, Y. (TU Delft Pavement Engineering); Tao, Q. (TU Delft ImPhys/Tao group)","Camara, Oscar (editor); Puyol-Antón, Esther (editor); Suinesiaputra, Avan (editor); Young, Alistair (editor); Sermesant, Maxime (editor); Tao, Qian (editor); Wang, Chengyan (editor)","2024","Deep learning-based methods have achieved prestigious performance for magnetic resonance imaging (MRI) reconstruction, enabling fast imaging for many clinical applications. Previous methods employ convolutional networks to learn the image prior as the regularization term. In quantitative MRI, the physical model of nuclear magnetic resonance relaxometry is known, providing additional prior knowledge for image reconstruction. However, traditional reconstruction networks are limited to learning the spatial domain prior knowledge, ignoring the relaxometry prior. Therefore, we propose a relaxometry-guided quantitative MRI reconstruction framework to learn the spatial prior from data and the relaxometry prior from MRI physics. Additionally, we also evaluated the performance of two popular reconstruction backbones, namely, recurrent variational networks (RVN) and variational networks (VN) with U-Net. Experiments demonstrate that the proposed method achieves highly promising results in quantitative MRI reconstruction.","Caridac MRI; Image reconstruction; Quantitative mapping; Relaxometry","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-02","","","ImPhys/Tao group","","",""
"uuid:a07ffbc9-2348-4c94-98c5-c17d7f25646b","http://resolver.tudelft.nl/uuid:a07ffbc9-2348-4c94-98c5-c17d7f25646b","Optimizing Neonatal Respiratory Support Through Network Modeling: A New Approach to Post-birth Infant Care","Sebahi, Yassine (Vrije Universiteit Amsterdam); Jabeen, F. (TU Delft Safety and Security Science); Treur, Jan (Vrije Universiteit Amsterdam); Taal, H. Rob (Erasmus MC); Roelofsma, Peter H.M.P. (Erasmus MC)","Cherifi, Hocine (editor); Rocha, Luis M. (editor); Cherifi, Chantal (editor); Donduran, Murat (editor)","2024","This paper presents an approach to enhancing neonatal care through the application of artificial intelligence (AI). Utilizing network-oriented modeling methodologies, the study aims to develop a network model to improve outcomes in neonatal respiratory support. The introduction sets the stage by outlining the significance of neonatal respiratory support and the challenges faced in this domain. The literature review delves into the existing body of work, highlighting the gaps and the need for a network modeling approach. The network-oriented modeling approach provides a robust framework that captures various states, such as world states, doctors’ mental states, and AI coach states, facilitating a comprehensive understanding of the complex interactions in neonatal respiratory support. Through Matlab simulations, the study investigates multiple scenarios, from optimal conditions to deviations from standard protocol. The main contribution focuses on the introduction of an AI coach, which serves as a real-time intervention mechanism to fill in the doctor's knowledge gaps. The research serves as a seminal work in the intersection of artificial intelligence and healthcare, demonstrating the potential of network-oriented modeling in improving patient outcomes and streamlining healthcare protocols.","Adaptive network model; AI Coach; Infant Care","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-21","","","Safety and Security Science","","",""
"uuid:23a20d2a-6107-4fd3-a3b9-31649179578a","http://resolver.tudelft.nl/uuid:23a20d2a-6107-4fd3-a3b9-31649179578a","Active Acoustic Metamaterial Based on Helmholtz Resonators to Absorb Broadband Low-Frequency Noise","Hedayati, R. (TU Delft Novel Aerospace Materials); Lakshmanan, Sandhya P. (Student TU Delft)","","2024","The aim of the present work is to design active acoustic metamaterial consisting of an array of Helmholtz resonators and fabricating them using an additive manufacturing technique in order to assist in a reduction in noise levels in aerospace applications. To this aim, initially, a passive metamaterial consisting of an array of 64 Helmholtz resonator unit cells is designed and tested to establish the effectiveness and region of performance. The selected design variable for change is identified as the resonator cavity depth through the frequency response for each parameter of the Helmholtz resonance equation and randomized to achieve a broadband frequency range of the passive metamaterial. An active model of this design (actuated by a stepper motor) is fabricated and tested. The metamaterials are tested under two acoustic set-ups: a closed system aimed at recreating the environment of a soundproof room and an open-system aimed to recreate the condition of an active liner. For the case of passive system, the metamaterial gave sound attenuation of 18 dB (for f = 150 Hz) in open system configuration and 33 dB (f = 350 Hz) in closed system configuration. The attenuation obtained for the active model was 10–15 dB over the mean line performance for the case of closed system and 15–20 dB for the case of open system. The closed system was also tested for performance at multiple cavity depths by setting two wall depths at 10 mm and three walls at 50 mm. This test yielded an attenuation of 15 dB at 180 Hz, the frequency corresponding to 50 mm cavity depth, and 10 dB at 515 Hz, corresponding to 10 mm cavity depth.","acoustic metamaterial; additive manufacturing; Helmholtz resonator; noise attenuation","en","journal article","","","","","","","","","","","Novel Aerospace Materials","","",""
"uuid:b308297a-8cf3-4c6a-886e-1d1903377efd","http://resolver.tudelft.nl/uuid:b308297a-8cf3-4c6a-886e-1d1903377efd","Modeling dynamic stall of an airfoil with vortex generators using a double-wake panel model with viscous–inviscid interaction","Yu, W. (TU Delft Wind Energy); Bajarūnas, Lukas K. (Student TU Delft); Zanon, Alessandro (AIT Austrian Institute of Technology); Ferreira, Carlos J.S.","","2024","Vortex generators (VGs) have been widely applied to wind turbines thanks to their potential to increase aerodynamic performance. Due to the complex inflow perceived by a rotor and the proneness to flow separation, VGs on wind turbines usually experience highly unsteady flow. While there are models that exist to simulate the steady effects of VGs, we lack a fast and efficient tool to model the unsteady performance of airfoils equipped with VGs. This paper adopts an unsteady double-wake panel model with viscous–inviscid interaction developed to simulate a vertical axis turbine in dynamic stall, adding the capability of predicting the dynamic aerodynamic performance of VG-equipped airfoils. The results of a series of steady and unsteady cases of an airfoil with different VG configurations in various pitch motions in free and forced transition are verified against experimental data. Results show that the double wake model offers results with sufficient accuracy compared with experimental data to claim the model's validity in a preliminary evaluation of an airfoil's capability to prevent stall with VGs. A few limitations, including the accuracy in prediction the transition location, separation, and reattachment, have been identified for future development.","double wake; dynamic stall; viscous–inviscid interaction; vortex generators; vortex panel method","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:5497947b-8b42-45d1-8eff-a63e3b7491ab","http://resolver.tudelft.nl/uuid:5497947b-8b42-45d1-8eff-a63e3b7491ab","Thermally self-sufficient heat pump-assisted azeotropic dividing-wall column for biofuels recovery from isopropanol-butanol-ethanol fermentation","Jankovic, T.J. (TU Delft BT/Bioprocess Engineering); Straathof, Adrie J.J. (TU Delft BT/Bioprocess Engineering); Kiss, A.A. (TU Delft ChemE/Product and Process Engineering)","","2024","Isopropanol-butanol-ethanol (IBE) fermentation is a superior biofuel production technology as compared to acetone-butanol-ethanol (ABE) fermentation due to the better fuel properties of the obtained products. However, low product concentrations, thermodynamic constraints and the presence of microorganisms lead to complex downstream processing that limits the competitiveness of this biofuel production method. Thus, this original research proposes a novel thermally self-sufficient and eco-efficient downstream process for industrial-scale recovery after IBE fermentation (74 ktonne/y capacity), from a highly dilute broth (>97 wt% water). Gas stripping and heat pump-assisted vacuum evaporation were implemented to separate valuable products from most of the broth. Furthermore, an advanced highly integrated heat pump-assisted azeotropic dividing-wall column was designed to recover high-purity (99 wt%) butanol biofuel and isopropanol – ethanol fuel supplement (89 wt%). The proposed purification process recovers over 99 % of biofuel products in a cost-effective (0.130 $/kgIBE) and energy-efficient way (0.673 kWeh/kgIBE) while allowing full recycle of biomass and most of the separated water. Besides improving yield by continuously recovering the inhibitory products, fermentation can be further enhanced by avoiding biomass loss and reducing water requirements. Lastly, the implemented energy-saving techniques ensure complete electrification of the proposed IBE recovery process. Therefore, the original results of this research study significantly contribute to the development of sustainable biofuel production processes.","Azeotropic dividing-wall column; Downstream processing; Heat pumps; Process electrification; Process intensification","en","journal article","","","","","","","","","","","BT/Bioprocess Engineering","","",""
"uuid:876fad45-94fd-4f78-a250-a48a4d229216","http://resolver.tudelft.nl/uuid:876fad45-94fd-4f78-a250-a48a4d229216","MACE: Automated Assessment of Stereochemistry of Transition Metal Complexes and Its Applications in Computational Catalysis","Chernyshov, I. (TU Delft ChemE/Inorganic Systems Engineering); Pidko, E.A. (TU Delft ChemE/Inorganic Systems Engineering)","","2024","Computational chemistry pipelines typically commence with geometry generation, well-established for organic compounds but presenting a considerable challenge for transition metal complexes. This paper introduces MACE, an automated computational workflow for converting chemist SMILES/MOL representations of the ligands and the metal center to 3D coordinates for all feasible stereochemical configurations for mononuclear octahedral and square planar complexes directly suitable for quantum chemical computations and implementation in high-throughput computational chemistry workflows. The workflow is validated through a structural screening of a data set of transition metal complexes extracted from the Cambridge Structural Database. To further illustrate the power and capabilities of MACE, we present the results of a model DFT study on the hemilability of pincer ligands in Ru, Fe, and Mn complexes, which highlights the utility of the workflow for both focused mechanistic studies and larger-scale high-throughput pipelines.","","en","journal article","","","","","","","","","","","ChemE/Inorganic Systems Engineering","","",""
"uuid:56ad355d-48e7-414d-b431-09e62987db79","http://resolver.tudelft.nl/uuid:56ad355d-48e7-414d-b431-09e62987db79","Empirical assessment of ChatGPT’s answering capabilities in natural science and engineering","Schulze Balhorn, L. (TU Delft ChemE/Process Systems Engineering); Weber, J.M. (TU Delft Pattern Recognition and Bioinformatics); Buijsman, S.N.R. (TU Delft Ethics & Philosophy of Technology); Hildebrandt, Julian R. (Rheinisch-Westfälische Technische Hochschule); Ziefle, Martina (Rheinisch-Westfälische Technische Hochschule); Schweidtmann, A.M. (TU Delft ChemE/Process Systems Engineering)","","2024","ChatGPT is a powerful language model from OpenAI that is arguably able to comprehend and generate text. ChatGPT is expected to greatly impact society, research, and education. An essential step to understand ChatGPT’s expected impact is to study its domain-specific answering capabilities. Here, we perform a systematic empirical assessment of its abilities to answer questions across the natural science and engineering domains. We collected 594 questions on natural science and engineering topics from 198 faculty members across five faculties at Delft University of Technology. After collecting the answers from ChatGPT, the participants assessed the quality of the answers using a systematic scheme. Our results show that the answers from ChatGPT are, on average, perceived as “mostly correct”. Two major trends are that the rating of the ChatGPT answers significantly decreases (i) as the educational level of the question increases and (ii) as we evaluate skills beyond scientific knowledge, e.g., critical attitude.","","en","journal article","","","","","","","","","","","ChemE/Process Systems Engineering","","",""
"uuid:ab572c7a-efc9-4c55-8190-d81edd4929c3","http://resolver.tudelft.nl/uuid:ab572c7a-efc9-4c55-8190-d81edd4929c3","Assessing sampling and retrieval errors of GPROF precipitation estimates over the Netherlands","Bogerd, Linda (Wageningen University & Research; Royal Netherlands Meteorological Institute (KNMI)); Leijnse, Hidde (Royal Netherlands Meteorological Institute (KNMI)); Overeem, A. (TU Delft Water Resources; Royal Netherlands Meteorological Institute (KNMI)); Uijlenhoet, R. (TU Delft Water Resources)","","2024","The Goddard Profiling algorithm (GPROF) converts radiometer observations from Global Precipitation Measurement (GPM) constellation satellites into precipitation estimates. Typically, high-quality ground-based estimates serve as reference to evaluate GPROF's performance. To provide a fair comparison, the ground-based estimates are often spatially aligned to GPROF. However, GPROF combines observations from various sensors and channels, each associated with a distinct footprint. Consequently, uncertainties related to the representativeness of the sampled areas are introduced in addition to the uncertainty when converting brightness temperatures into precipitation intensities. The exact contribution of resampling precipitation estimates, required to spatially and temporally align different resolutions when combining or comparing precipitation observations, to the overall uncertainty remains unknown. Here, we analyze the current performance of GPROF over the Netherlands during a 4-year period (2017-2020) while investigating the uncertainty related to sampling. The latter is done by simulating the reference precipitation as satellite footprints that vary in size, geometry, and applied weighting technique. Only GPROF estimates based on observations from the conical-scanning radiometers of the GPM constellation are used. The reference estimates are gauge-adjusted radar precipitation estimates from two ground-based weather radars from the Royal Netherlands Meteorological Institute (KNMI). Echo top heights (ETHs) retrieved from the same radars are used to classify the precipitation as shallow, medium, or deep. Spatial averaging methods (Gaussian weighting vs. arithmetic mean) minimally affect the magnitude of the precipitation estimates. Footprint size has a higher impact but cannot explain all discrepancies between the ground- and satellite-based estimates. Additionally, the discrepancies between GPROF and the reference are largest for low ETHs, while the relative bias between the different footprint sizes and implemented weighting methods increase with increasing ETHs. Lastly, our results do not show a clear difference between coastal and land simulations. We conclude that the uncertainty introduced by merging different channels and sensors cannot fully explain the discrepancies between satellite- and ground-based precipitation estimates. Hence, uncertainties related to the retrieval algorithm and environmental conditions are found to be more prominent than resampling uncertainties, in particular for shallow and light precipitation.","","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:23b9219a-5b46-41b0-83de-021e07ada898","http://resolver.tudelft.nl/uuid:23b9219a-5b46-41b0-83de-021e07ada898","Hamiltonian phase error in resonantly driven CNOT gate above the fault-tolerant threshold","Wu, Yi Hsien (National Taiwan University; RIKEN); Camenzind, Leon C. (RIKEN); Noiri, Akito (RIKEN); Takeda, Kenta (RIKEN); Nakajima, Takashi (RIKEN); Kobayashi, Takashi (RIKEN); Chang, Chien Yuan (RIKEN); Sammak, A. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre); Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Tarucha, Seigo (RIKEN)","","2024","Because of their long coherence time and compatibility with industrial foundry processes, electron spin qubits are a promising platform for scalable quantum processors. A full-fledged quantum computer will need quantum error correction, which requires high-fidelity quantum gates. Analyzing and mitigating gate errors are useful to improve gate fidelity. Here, we demonstrate a simple yet reliable calibration procedure for a high-fidelity controlled-rotation gate in an exchange-always-on Silicon quantum processor, allowing operation above the fault-tolerance threshold of quantum error correction. We find that the fidelity of our uncalibrated controlled-rotation gate is limited by coherent errors in the form of controlled phases and present a method to measure and correct these phase errors. We then verify the improvement in our gate fidelities by randomized benchmark and gate-set tomography protocols. Finally, we use our phase correction protocol to implement a virtual, high-fidelity, controlled-phase gate.","","en","journal article","","","","","","","","","","","BUS/TNO STAFF","","",""
"uuid:dcfaea53-3e8a-46c5-82a5-95c360861277","http://resolver.tudelft.nl/uuid:dcfaea53-3e8a-46c5-82a5-95c360861277","Draft genome sequence of the Saccharomyces cerevisiae SpyCas9 expressing strain IMX2600, a laboratory and platform strain from the CEN.PK lineage for cell-factory research","van den Broek, M.A. (TU Delft BT/Industriele Microbiologie); Ortiz Merino, R.A. (TU Delft Research Data and Software); Bennis, N.X. (TU Delft BT/Industriele Microbiologie); Wronska, A.K. (TU Delft BT/Industriele Microbiologie); Else-Hassing, J. (TU Delft BT/Industriele Microbiologie); Daran-Lapujade, P.A.S. (TU Delft BT/Industriele Microbiologie); Daran, J.G. (TU Delft BT/Industriele Microbiologie)","","2024","The biobased-economy aims to create a circular biotechnology ecosystem to transition from a fossil fuel-based to a sustainable industry based on biomass. For this, new microbial cell-factories are essential. We present the draft genome of the CEN.PK-derived Saccharomyces cerevisiae SpyCas9 expressing strain (IMX2600), that serve as chassis of new cell-factories.","biotechnology; cell factory; CRISPR; metabolic engineering; Saccharomyces cerevisiae","en","journal article","","","","","","","","","","","BT/Industriele Microbiologie","","",""
"uuid:c4a44233-af1b-479d-830f-d0bef8f10fb9","http://resolver.tudelft.nl/uuid:c4a44233-af1b-479d-830f-d0bef8f10fb9","Role of the composition of humic substances formed during thermal hydrolysis process on struvite precipitation in reject water from anaerobic digestion","Pavez Jara, J.A. (TU Delft Sanitary Engineering); Iswarani, W.P. (TU Delft Water Resources; TU Delft Support Water Management; Wetsus, Centre for Sustainable Water Technology); van Lier, J.B. (TU Delft Sanitary Engineering); de Kreuk, M.K. (TU Delft Water Management)","","2024","Thermal hydrolysis process (THP) is a widely used pre-treatment method in the anaerobic digestion (AD) of waste municipal sewage sludge. A post AD dewatering step of the digestate produces a liquid stream called reject water. THP increases the concentration of humic substances (HSs) and nutrients in the produced reject water. Struvite precipitation is a widely used technique to remove and (potentially) recover PO43− -P and the corresponding amount of total ammoniacal nitrogen from reject water. The chemical characteristics of the THP-produced HSs influence reaction yields and morphology of struvite. In our current study, struvite batch precipitation experiments were conducted at different pHs, and different concentrations of HSs, consisting of either melanoidins or humic acids. Our results showed that at pH 6.5 struvite precipitation was severely retarded. However, increased concentrations of melanoidins at pH 6.5 enhanced struvite precipitation. Batch experiments conducted at pH 7.25 and 8 with increased melanoidins concentrations showed PO43−-P precipitation yields over 86 %. Humic acids negatively impacted struvite precipitation at all analysed pH values, presumably because of Mg2+ complexation. Morphological analysis showed that the presence of both HSs affected Feret diameters, aspect ratio, and cleavage pattern of struvite. Also, HSs rendered coloured crystals. Overall, our results showed that struvite precipitation is affected by HSs intrinsic characteristics, affecting yield, morphology, and colour of the formed precipitates.","Humic acid; Melanoidins; Phosphate recovery; Struvite; Thermal hydrolysis process","en","journal article","","","","","","","","","","Water Management","Sanitary Engineering","","",""
"uuid:3877f7bb-dfa4-40c7-aac2-6977bf782144","http://resolver.tudelft.nl/uuid:3877f7bb-dfa4-40c7-aac2-6977bf782144","Samen op reis?: Een verkenning naar integratie mogelijkheden voor personen- en goederenvervoer in rotterdam","van Duin, Ron (TU Delft Transport and Logistics; Rotterdam University of Applied Sciences); de Vries, A.M.R. (Rotterdam University of Applied Sciences); Anand, N.R. (Rotterdam University of Applied Sciences)","Weijers, S.J.C.M. (editor); Vannieuwenhuyse, B.J. (editor)","2024","De komende jaren zullen steden meer en meer te maken krijgen met uitdagingen op het gebied van vervoer in termen van toegankelijkheid, ruimtegebruik en duurzaamheid. Het passagiers- en goederenvervoer zullen naar verwachting toenemen, terwijl de transportsector een belangrijke bijdrage levert aan de uitstoot van broeikasgassen en congestie in steden. Hoewel beide ecosystemen (personenvervoer en vrachtvervoer) historisch gezien met elkaar verweven waren, hebben de ecosystemen zich de afgelopen eeuw afzonderlijk van elkaar ontwikkeld. Dit onderzoek richt zich op het vinden van geïntegreerde logistieke stromen en logistieke innovaties en vooral op het vinden van de voorwaarden waaronder deze kunnen worden toegevoegd aan verschillende soorten mobiliteitsknooppunten. Door informatie uit literatuur en interviews te verzamelen en te structureren met behulp van een behoefteanalyse, werd het mogelijk om wijk-/stad-/buiten stad-hubs te definieren.
Met deze raamwerken is gekeken welke logistieke functies hieraan toegevoegd kunnen worden. De raamwerken zijn empirisch getest en gevalideerd door studenten van de Hogeschool Rotterdam voor verschillende metrostations in Rotterdam. De raamwerken geven duidelijk sturing wat men zou kunnen ontwikkelen op het gebied van integratie van personen- en goederenvervoer.
As we aim to show in this chapter, we believe this hunch largely panned out – though there are clear areas for future improvement pertaining to the pilot exercise itself and the research we conducted on the exercise. We begin by offering a description of our tinkering exercise. We discuss the exercise’s source of inspiration (Sect. 16.2.1) and its implementation (Sect. 16.2.2), which is visually captured via photographic documentation. We then discuss (Sect. 16.3) how we utilized a triangulated research method to assess the pedagogical value of the exercise. After we discuss our findings, we conclude by identifying areas for future improvement (Sect. 16.4).","Neurodiversity; Ableism; Engineering ethics education; Tinkering; Inclusivity","en","book chapter","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-23","","","Ethics & Philosophy of Technology","","",""
"uuid:14fe9f4a-1c21-452e-95ab-51d164e05619","http://resolver.tudelft.nl/uuid:14fe9f4a-1c21-452e-95ab-51d164e05619","Diversifying Knowledge Production in HCI: Exploring Materiality and Novel Formats for Scholarly Expression","Sturdee, Miriam (University of St Andrews); Genç, H.U. (TU Delft Human-Centred Artificial Intelligence); Wanick, Vanissa (University of Southampton)","","2024","This one-day studio aims to catalyze discussions and experimentation around non-textual academic documentation methods. With the understanding that human knowledge transcends written words, we aim to explore innovative ways to present and disseminate research outputs in diverse forms and of varying materiality. By bringing together researchers, practitioners, and academics from different disciplines and backgrounds, we seek to challenge the status quo of textual output and envision a future where knowledge production embraces the multisensory nature of human data.","futuring; knowledge production; pictorials; process; research output; tangible","en","conference paper","Association for Computing Machinery (ACM)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-11","","","Human-Centred Artificial Intelligence","","",""
"uuid:b732b5b3-09d9-4c0d-af91-978d1bf1c51a","http://resolver.tudelft.nl/uuid:b732b5b3-09d9-4c0d-af91-978d1bf1c51a","Unveiling the bent-jet structure and polarization of OJ 287 at 1.7 GHz with space VLBI","Cho, Ilje (Instituto de Astrofísica de Andalucía-Consejo Superior de Investigaciones Científicas (CSIC); Korea Astronomy and Space Science Institute; Yonsei University); Gómez, José L. (Instituto de Astrofísica de Andalucía-Consejo Superior de Investigaciones Científicas (CSIC)); Lico, Rocco (Instituto de Astrofísica de Andalucía-Consejo Superior de Investigaciones Científicas (CSIC); INAF Istituto di Radioastronomia); Zhao, Guang Yao (Instituto de Astrofísica de Andalucía-Consejo Superior de Investigaciones Científicas (CSIC); Max-Planck-Institute for Radio Astronomy); Traianou, Efthalia (Instituto de Astrofísica de Andalucía-Consejo Superior de Investigaciones Científicas (CSIC)); Dahale, Rohan (Instituto de Astrofísica de Andalucía-Consejo Superior de Investigaciones Científicas (CSIC)); Fuentes, Antonio (Instituto de Astrofísica de Andalucía-Consejo Superior de Investigaciones Científicas (CSIC)); Toscano, Teresa (Instituto de Astrofísica de Andalucía-Consejo Superior de Investigaciones Científicas (CSIC)); Gurvits, L. (TU Delft Astrodynamics & Space Missions; Joint Institute for VLBI ERIC)","","2024","We present total intensity and linear polarization images of OJ 287 at 1.68 GHz, obtained through space-based very long baseline interferometry (VLBI) observations with RadioAstron on April 16, 2016. The observations were conducted using a ground array consisting of the Very Long Baseline Array (VLBA) and the European VLBI Network (EVN). Ground-space fringes were detected with a maximum projected baseline length of ∼5.6 Earth's diameter, resulting in an angular resolution of ∼530 μas. With this unprecedented resolution at such a low frequency, the progressively bending jet structure of OJ 287 has been resolved up to ∼10 parsec of the projected distance from the radio core. In comparison with close-in-time VLBI observations at 15, 43, 86 GHz from MOJAVE and VLBA-BU-BLAZAR monitoring projects, we obtain the spectral index map showing the opaque core and optically thin jet components. The optically thick core has a brightness temperature of ∼1013 K, and is further resolved into two sub-components at higher frequencies labeled C1 and C2. These sub-components exhibit a transition from optically thick to thin, with a synchrotron self-absorption (SSA) turnover frequency estimated to be ∼33 and ∼11.5 GHz, and a turnover flux density ∼4 and ∼0.7 Jy, respectively. Assuming a Doppler boosting factor of 10, the SSA values provide the estimate of the magnetic field strengths from SSA of ∼3.4 G for C1 and ∼1.0 G for C2. The magnetic field strengths assuming equipartition arguments are also estimated as ∼2.6 G and ∼1.6 G, respectively. The integrated degree of linear polarization is found to be approximately ∼2.5%, with the electric vector position angle being well aligned with the local jet direction at the core region. This alignment suggests a predominant toroidal magnetic field, which is in agreement with the jet formation model that requires a helical magnetic field anchored to either the black hole ergosphere or the accretion disk. Further downstream, the jet seems to be predominantly threaded by a poloidal magnetic field.","Galaxies: active; Galaxies: jets; Quasars: supermassive black holes; Radio continuum: galaxies","en","journal article","","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:59557f1c-676e-40d3-90a4-0861ee0ccd2e","http://resolver.tudelft.nl/uuid:59557f1c-676e-40d3-90a4-0861ee0ccd2e","“O.R. GOES GREEN”: a first step toward reducing our carbon footprint in the operating room and hospital","Leone, Nicola (University of Turin); Scozzari, Gitana (Città della Salute e Delle Scienze Molinette); Olandese, Francesco (University of Turin); Horeman, T. (TU Delft Medical Instruments & Bio-Inspired Technology); Passera, Roberto (University of Turin); Arezzo, Alberto (University of Turin); Morino, Mario (University of Turin)","","2024","Hospitals in Europe produce approximately 6 million tons of medical waste annually, about one-third of this originating in operating rooms. Most of it is solid waste, which can be recycled if bodily fluids do not contaminate it. Only 2–3% of hospital waste must be disposed of as infectious waste, and this is much lower than the 50–70% of garbage in the biohazard waste stream. In June 2021, at the main operating room of the Department of General Surgery of the University of Turin, we began a separate collection program for materials consisting of plastic, paper, TNT (material not contaminated by bodily fluids), and biohazardous waste. We calculated the number of boxes and the weight of special waste disposed produced every month in one operating room for 18 months. The monthly number of Sanibox and the monthly weight of biohazardous waste decreased during the observation period. The reduction trend was not constant but showed variations during the 18 months. Direct proportionality between number of low-complexity procedures and production of biohazardous waste was found (p = 0.050). We observed an optimization in the collection and filling of plastic, paper and TNT boxes separated and sent for recycling. One of the barriers to recycling hospital waste, and surgical waste in particular, is the failure to separate infectious waste from clean waste. A careful separate collection of waste in the operating room is the first step in reducing environmental pollution and management costs for the disposal of hospital waste.","Biohazardous waste; Carbon footprint; Environment pollution; Hospital waste; Operating room; Separate collection waste","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:31146219-7650-4690-987b-8fd1b4fa82d2","http://resolver.tudelft.nl/uuid:31146219-7650-4690-987b-8fd1b4fa82d2","SymFormer: End-to-End Symbolic Regression Using Transformer-Based Architecture","Vastl, Martin (Charles University); Kulhanek, Jonas (Czech Technical University); Kubalik, Jiri (Czech Technical University); Derner, Erik (Czech Technical University); Babuska, R. (TU Delft Learning & Autonomous Control)","","2024","Many real-world systems can be naturally described by mathematical formulas. The task of automatically constructing formulas to fit observed data is called symbolic regression. Evolutionary methods such as genetic programming have been commonly used to solve symbolic regression tasks, but they have significant drawbacks, such as high computational complexity. Recently, neural networks have been applied to symbolic regression, among which the transformer-based methods seem to be most promising. After training a transformer on a large number of formulas, the actual inference, i.e., finding a formula for new, unseen data, is very fast (in the order of seconds). This is considerably faster than state-of-the-art evolutionary methods. The main drawback of transformers is that they generate formulas without numerical constants, which have to be optimized separately, yielding suboptimal results. We propose a transformer-based approach called SymFormer, which predicts the formula by outputting the symbols and the constants simultaneously. This helps to generate formulas that fit the data more accurately. In addition, the constants provided by SymFormer serve as a good starting point for subsequent tuning via gradient descent to further improve the model accuracy. We show on several benchmarks that SymFormer outperforms state-of-the-art methods while having faster inference.","neural networks; Symbolic regression; transformers","en","journal article","","","","","","","","","","","Learning & Autonomous Control","","",""
"uuid:cf475a74-24fe-4f30-b133-c8bec3155acb","http://resolver.tudelft.nl/uuid:cf475a74-24fe-4f30-b133-c8bec3155acb","Delayed choice experiments: an analysis in forward time","Waaijer, Marijn (Student TU Delft); van Neerven, J.M.A.M. (TU Delft Analysis)","","2024","In this article, we present a detailed analysis of two famous delayed choice experiments: Wheeler’s classic gedanken-experiment and the delayed quantum eraser. Our analysis shows that the outcomes of both experiments can be fully explained on the basis of the information collected during the experiments using textbook quantum mechanics only. At no point in the argument, information from the future is needed to explain what happens next. In fact, more is true: for both experiments, we show, in a strictly mathematical way, that a modified version in which the time-ordering of the steps is changed to avoid the delayed choice leads to exactly the same final state. In this operational sense, the scenarios are completely equivalent in terms of conclusions that can be drawn from their outcomes.","Delayed choice; Delayed quantum eraser; Retro-causality; Wheeler’s gedanken-experiment","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:2ae6282f-ea50-496b-8df2-daf13d148515","http://resolver.tudelft.nl/uuid:2ae6282f-ea50-496b-8df2-daf13d148515","Hierarchical online energy management for residential microgrids with Hybrid hydrogen–electricity Storage System","Wu, J. (TU Delft Intelligent Electrical Power Grids; Aalborg University); Li, S. (TU Delft Intelligent Electrical Power Grids; Aalborg University); Fu, A. (TU Delft Intelligent Electrical Power Grids); Cvetkovic, M. (TU Delft Intelligent Electrical Power Grids); Palensky, P. (TU Delft Electrical Sustainable Energy); Vasquez, Juan C. (Aalborg University); Guerrero, Josep M. (Aalborg University; Universitat Politecnica de Catalunya; Catalan Institution for Research and Advanced Studies (ICREA))","","2024","The increasing proportion of renewable energy introduces both long-term and short-term uncertainty to power systems, which restricts the implementation of energy management systems (EMSs) with high dependency on accurate prediction techniques. A hierarchical online EMS (HEMS) is proposed in this paper to economically operate the Hybrid hydrogen–electricity Storage System (HSS) in a residential microgrid (RMG). The HEMS dispatches an electrolyzer-fuel cell-based hydrogen energy storage (ES) unit for seasonal energy shifting and an on-site battery stack for daily energy allocation against the uncertainty from the renewable energy source (RES) and demand side. The online decision-making of the proposed HEMS is realized through two parallel fuzzy logic (FL)-based controllers which are decoupled by different operating frequencies. An original local energy estimation model (LEEM) is specifically designed for the decision process of FL controllers to comprehensively evaluate the system status and quantify the electricity price expectation for the HEMS. The proposed HEMS is independent of RES prediction or load forecasting, and gives the optimal operation for HSS in separated resolutions: the hydrogen ES unit is dispatched hourly and the battery is operated every minute. The performance of the proposed method is verified by numerical experiments fed by real-world datasets. The superiority of the HEMS in expense-saving manner is validated through comparison with PSO-based day-ahead optimization methods, fuzzy logic EMS, and rule-based online EMS.","Energy management; Fuzzy logic; Hybrid storage system; Microgrid","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-23","","Electrical Sustainable Energy","Intelligent Electrical Power Grids","","",""
"uuid:a5d2c3a1-d025-4ccf-af4a-d691aef2cbbf","http://resolver.tudelft.nl/uuid:a5d2c3a1-d025-4ccf-af4a-d691aef2cbbf","Thermal time as an unsharp observable","van Neerven, J.M.A.M. (TU Delft Analysis); Portal, Pierre (Australian National University)","","2024","We show that the Connes-Rovelli thermal time associated with the quantum harmonic oscillator can be described as an (unsharp) observable, that is, as a positive operator valued measure. We furthermore present extensions of this result to the free massless relativistic particle in one dimension and to a hypothetical physical system whose equilibrium state is given by the noncommutative integral.","","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:e0007f25-9982-4646-83a0-4313e910522f","http://resolver.tudelft.nl/uuid:e0007f25-9982-4646-83a0-4313e910522f","Fractional periodic boundary value and Cauchy problems with Hilfer–Prabhakar operator","Marynets, K. (TU Delft Mathematical Physics); Tomovski, Živorad (University of Ostrava; Palacky University)","","2024","We introduce a successive approximations method to study one fractional periodic boundary value problem of the Hilfer-Prabhakar type. The problem is associated to the corresponding Cauchy problem, whose solution depends on an unknown initial value. To find this value we numerically solve the so-called ’determining system’ of algebraic or transcendental equations. As a result, we determine an approximate solution of the studied problem, written in a closed form. Finally, we evaluate efficiency of our method on a nonlinear numerical example.","Cauchy problem; Determining system; Hilfer–Prabhakar fractional derivative; Periodic boundary conditions; Successive approximations","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:e4fd9d87-86dd-4048-a9df-731ed2ba8f40","http://resolver.tudelft.nl/uuid:e4fd9d87-86dd-4048-a9df-731ed2ba8f40","Architecture of Oxfordian coral buildups along the Atlantic margin of Morocco","Duval-Arnould, Aude (The University of Manchester); Bulot, Luc (The University of Manchester); Charton, R.J.G. (TU Delft Applied Geology); Jain, Sreepat (Adama Science and Technology University); Masrour, Moussa (Ibn Zohr University); Pomar, Luis (University of the Balearic Islands); Redfern, Jonathan (The University of Manchester); Simmons, Mike (Neftex-Halliburton); Schröder, Stefan (The University of Manchester)","","2024","Oxfordian (Upper Jurassic) coral buildups developed widely in Tethys and Atlantic realms, during a time when paleoclimate potentially swung between greenhouse climate and cold snaps. Buildups were constructed by platy and branching corals, sponges and microbialites. Although their initiation is commonly linked to the Upper Jurassic global transgression, a number of global and local factors may have influenced buildup growth and demise (e.g. climate, shelf geometry, detrital input). Extensive outcrops of Oxfordian buildups in Morocco provide an opportunity to investigate the relationship between external drivers and buildup fauna and architecture. Here we show that the interplay of local accommodation changes, rising sea water temperature, and increasing pCO2 linked to the onset of the Middle Oxfordian global transgression were the main drivers for buildup initiation, which was synchronous across the basin. The demise of the coral buildups in Morocco was linked to a regression, dated no later than Upper Oxfordian, the establishment of partly evaporitic conditions across the basin, and to localized influx of coarse-grained siliciclastics, the latter likely driven by synsedimentary tectonic activity. Serial logged sections, outcrop panoramas and detailed facies analysis show that low-relief deeper-water buildups of Dimorpharaea platy corals evolved into higher-relief diversified buildups where shallower-water reworking produced coral rubble and large clinoforms. Buildup diachronicity is apparent, with younger coral bioherms growing in the depressions created between the initial bioherms. Size of buildups ranges from 2 m wide and 0.5 m thick, to 700 m wide and 80 m thick. The outcrops provide constraints on geobody architecture and heterogeneity in the subsurface of Morocco and North America, where facies-controlled dolomitization of high-energy buildup and clinoform facies is a main driver for porosity development.","Coral buildup; Oxfordian; Platy coral; Reef architecture; Subsurface analog","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:578d58b2-5611-4a5e-a980-0b351a70f317","http://resolver.tudelft.nl/uuid:578d58b2-5611-4a5e-a980-0b351a70f317","Analysis of safe and effective next-generation rail signalling systems","Aoun, J. (TU Delft Transport and Planning); Goverde, R.M.P. (TU Delft Transport and Planning); Nardone, Roberto (Università degli Studi di Napoli Parthenope); Quaglietta, E. (TU Delft Transport and Planning); Vittorini, Valeria (Università degli Studi di Napoli Federico II)","","2024","Moving Block (MB) and Virtual Coupling (VC) rail signalling will change current train operation paradigm by migrating vital equipment from trackside to onboard to reduce train separation and maintenance costs. Their actual deployment is however constrained by the industry's need to identify configurations of MB and VC signalling equipment which can effectively guarantee safe train movements even under degraded operational conditions involving component faults. In this paper, we analyse the effectivity of MB and VC in safely supervising train separation under nominal and degraded conditions by using an innovative approach which combines Fault Tree Analysis (FTA) and Stochastic Activity Networks (SAN). An FTA model of unsafe train movement is defined for both MB and VC capturing functional interactions and cause-effect relations among the different signalling components. The FTA is used as a basis to apportion signalling component failure rates needed to feed the SAN model. Effective MB and VC train supervision is analysed by means of SAN-based simulations in the specific scenario of an error in the Train Position Report (TPR) for five rail market segments featuring different traffic characteristics, namely high-speed, mainline, regional, urban and freight. Results show that the thresholds of the design variables depend on the considered signalling system alternative and the investigated market segment. In particular, the TPR delay threshold allowed for MB is higher than for VC. This means that to ensure a safe train movement, VC cannot absorb a TPR delay of longer than 1.5 s, which corresponds to the mainline market segment. For MB instead, the results show that the maximum TPR delay can reach 3.9 s for high-speed and freight railways. In addition, results showed that the integration of an FTA in a SAN model can provide a better understanding of the safety-performance behaviour of a system where VC showed a higher number of braking indications with respect to MB for the same TPR error failure rate. This means that for VC to effectively supervise the train separation at the same safety level as MB, we would need to have a much higher reliability of the TPR. The overall approach can support infrastructure managers, railway undertakings, and rail signalling suppliers in investigating the effectiveness of MB and VC to safely supervise train movements in scenarios involving different types of degraded conditions and failure events. The proposed method can hence support the railway industry in identifying effective and safe design configurations of next-generation rail signalling systems.","Moving Block; Performance; Safety; Stochastic activity networks; Virtual Coupling","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:56d2e2f8-a393-490f-b1c8-75819640651a","http://resolver.tudelft.nl/uuid:56d2e2f8-a393-490f-b1c8-75819640651a","A mud budget of the Wadden Sea and its implications for sediment management","Colina Alonso, A. (TU Delft Coastal Engineering; Deltares); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares; East China Normal University); Oost, Albert Peter (Staatsbosbeheer); Esselink, Peter (PUCCIMAR; Rijksuniversiteit Groningen); Lepper, Robert (Bundesanstalt für Wasserbau); Kösters, Frank (Bundesanstalt für Wasserbau); Bartholdy, Jesper (University of Copenhagen); Bijleveld, Allert (NIOZ Royal Netherlands Institute for Sea Research); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2024","The world’s coasts and deltas are progressively threatened by climate change and human activities. The degree at which coastlines can adapt to these changes strongly depends on the sediment availability. The availability of muddy sediments is however poorly known. This study aims at developing a mud budget for the world’s largest system of uninterrupted tidal flats: the Wadden Sea. The resulting mud budget is nearly closed: ~ 12 million ton/year enters the system on its western end, ~ 1.5 million ton/year is added by local rivers, while ~ 12 million ton annually deposits or is extracted by anthropogenic activities. A mud deficit already exists in the downdrift areas, which will only become more pronounced with increased sea level rise rates. Mud is thus a finite resource similar to sand, and should be treated as such in sediment management strategies. Resolving future challenges will therefore require a cross-border perspective on sediment management.","sediment budget; Wadden Sea; morphodynamics; mud; intertidal flats","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:4c885f20-be76-47ef-b325-08b464a351bc","http://resolver.tudelft.nl/uuid:4c885f20-be76-47ef-b325-08b464a351bc","Ridesourcing platforms thrive on socio-economic inequality","de Ruijter, A.J.F. (TU Delft Transport and Planning); Cats, O. (TU Delft Transport and Planning); van Lint, J.W.C. (TU Delft Transport and Planning)","","2024","Limited available market share data seems to suggest that ridesourcing platforms benefit from, even thrive on, socio-economic inequality. We suspect that this is associated with high levels of socio-economic inequality allowing for cheap labour as well as increasing the share of travellers with a considerably above-average willingness to pay for travel time savings and comfort. We test the relation between inequality and system performance by means of an agent-based simulation model representing within-day and day-to-day supply-demand interaction in the ridesourcing market. The model captures travellers’ mode choice with a heterogeneous perception of relevant time components, as well as job seekers’ participation choice with heterogeneous reservation wage. Our experiments cover scenarios for the entire spectrum ranging from perfect equality to extreme inequality. For several of such scenarios, we explore alternative platform pricing strategies. Our analysis shows a strong, positive relationship between socio-economic inequality and ridesourcing market share. This is the outcome of the combination of cheap labour and time-sensitive ridesourcing users, reinforced by network effects inherent to ridesourcing markets. We find that driver earnings are minimal in urban areas with large socio-economic inequality. In such contexts, drivers are likely to face a high platform commission, and yet, fierce competition for passengers.","","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:8691dc0b-aff9-4f53-8a04-798374857bbe","http://resolver.tudelft.nl/uuid:8691dc0b-aff9-4f53-8a04-798374857bbe","Topological assessment of recoverability in public transport networks","Massobrio, R.M. (TU Delft Transport and Planning; Universiteit Antwerpen); Cats, O. (TU Delft Transport and Planning)","","2024","Reducing the impact of disruptions is essential to provide reliable and attractive public transport. In this work, we introduce a topological approach for evaluating recoverability, i.e., the ability of public transport networks to return to their original performance level after disruptions, which we model as topological perturbations. We assess recoverability properties in 42 graph representations of metro networks and relate these to various topological indicators. Graphs include infrastructure and service characteristics, accounting for in-vehicle travel time, waiting time, and transfers. Results show a high correlation between recoverability and topological indicators, suggesting that more efficient networks (in terms of the average number of hops and the travel time between nodes) and denser networks can better withstand disruptions. In comparison, larger networks that feature more redundancy can rebound faster to normal performance levels. The proposed methodology offers valuable insights for planners when designing new networks or enhancing the recoverability of existing ones.","","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:087a959f-3ce3-4ed4-9c7d-6edd7c2c6665","http://resolver.tudelft.nl/uuid:087a959f-3ce3-4ed4-9c7d-6edd7c2c6665","Feasibility of reservoir monitoring in the Groningen gas field using ghost reflections from seismic interferometry","Shirmohammadi, F. (TU Delft Applied Geophysics and Petrophysics); Draganov, D.S. (TU Delft Applied Geophysics and Petrophysics); Veltmeijer, A.V. (TU Delft Applied Geophysics and Petrophysics); Naderloo, M. (TU Delft Reservoir Engineering); Barnhoorn, A. (TU Delft Applied Geophysics and Petrophysics)","","2024","Seismic interferometry (SI) retrieves new seismic responses, for example reflections, between either receivers or sources. When SI is applied to a reflection survey with active sources and receivers at the surface, non-physical (ghost) reflections are retrieved as well. Ghost reflections, retrieved from the correlation of two primary reflections or multiples from two different depth levels, are only sensitive to the properties in the layer that cause them to appear in the result of SI, such as velocity, density and thickness. We aim to use these ghost reflections for monitoring subsurface changes, to address challenges associated with detecting and isolating changes within the target layer in monitoring. We focus on the feasibility of monitoring pore-pressure changes in the Groningen gas field in the Netherlands using ghost reflections. To achieve this, we utilize numerical modelling to simulate scalar reflection data, deploying sources and receivers at the surface. To build up subsurface models for monitoring purposes, we perform an ultrasonic transmission laboratory experiment to measure S-wave velocities at different pore pressures. Applying SI by autocorrelation to the modelled data sets, we retrieve zero-offset ghost reflections. Using a correlation operator, we determine time differences between a baseline survey and monitoring surveys. To enhance the ability to detect small changes, we propose subsampling the ghost reflections before the correlation operator and using only virtual sources with a complete illumination of receivers. We demonstrate that the retrieved time differences between the ghost reflections exhibit variations corresponding to velocity changes inside the reservoir. This highlights the potential of ghost reflections as valuable indicators for monitoring even small changes. We also investigate the effect of the sources and receivers’ geometry and spacing and the number of virtual sources and receivers in retrieving ghost reflections with high interpretability resolution.","Induced seismicity; Numerical modelling; Seismic interferometry","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:90ac8cd3-f09e-4b82-a586-f2cd70d64abb","http://resolver.tudelft.nl/uuid:90ac8cd3-f09e-4b82-a586-f2cd70d64abb","Editorial: Emerging on-demand passenger and logistics systems: Modelling, optimization, and data analytics","Ke, Jintao (The University of Hong Kong); Wang, Hai (Singapore Management University); Masoud, Neda (University of Michigan); Schiffer, Maximilian (Technische Universität München); Correia, Gonçalo (TU Delft Transport and Planning)","","2024","The proliferation of smart personal devices and mobile internet access has fueled numerous advancements in on-demand transportation services. These services are facilitated by online digital platforms and range from providing rides to delivering products. Their influence is transforming transportation systems and leaving a mark on changing individual mobility, activity patterns, and consumption behaviors. For instance, on-demand transportation companies such as Uber, Lyft, Grab, and DiDi have become increasingly vital for meeting urban transportation needs by connecting available drivers with passengers in real time. The recent surge in door-to-door food delivery (e.g., Uber Eats, DoorDash, Meituan); grocery delivery (e.g., Amazon Fresh, Picnik); and same-day courier services (e.g., Amazon Same-Day Delivery) has significantly enhanced both convenience and safety for customers, particularly during the COVID-19 pandemic.
Despite their rapid growth, on-demand transportation services bear several challenges for key stakeholders. The private sector, which includes online platforms, strives to optimize system efficiency and revenue through advanced artificial intelligence techniques and optimization methods. Meanwhile, the public sector aims to strike a balance between the interests of various stakeholders to create more sustainable, equitable, and eco-friendly mobility systems. As such, new mobility paradigms arise in which public authorities require decision support tools that offer realistic cost and benefit estimations for all parties involved. As these services continue to expand, researchers, operators, and policymakers can leverage the vast amount of data generated to better understand, model, analyze, and effectively coordinate both the supply and demand dynamics within these systems.","","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-25","","","Transport and Planning","","",""
"uuid:b591df82-e9c9-4b11-bd5a-d0e8f9591888","http://resolver.tudelft.nl/uuid:b591df82-e9c9-4b11-bd5a-d0e8f9591888","Reduced complexity for sound zones with subband block adaptive filters and a loudspeaker line array","Møller, Martin B. (Bang & Olufsen A/S); Martinez, Jorge (TU Delft Multimedia Computing); Østergaard, Jan (Aalborg University)","","2024","Sound zones are used to reproduce individual audio content to multiple people in a room using a set of loudspeakers with controllable input signals. To allow the reproduction of individual audio to dynamically change, e.g., due to moving listeners, changes in the number of listeners, or changing room transfer functions, an adaptive formulation is proposed. This formulation is based on frequency domain block adaptive filters and given room transfer functions. To reduce computational complexity, the system is extended to subband processing without cross-adaptive filters. The computational savings come from recognizing that sound zones consist of part-solutions which are inherently band limited, hence, several subbands can be ignored. To validate the theoretical findings, a 27-channel loudspeaker array was constructed, and measurements were performed in anechoic and reflective environments. The results show that the subband solution performs identically to a full-rate solution but at a reduced computational complexity.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-10-01","","","Multimedia Computing","","",""
"uuid:f988dab4-d585-4257-8c13-f8263b3e056f","http://resolver.tudelft.nl/uuid:f988dab4-d585-4257-8c13-f8263b3e056f","Aging and Sintered Layer Defect Detection of Discrete MOSFETs Using Frequency Domain Reflectometry Associated With Parasitic Resistance","Yun, Minghui (Guilin University of Electronic Technology); Yang, Daoguo (Guilin University of Electronic Technology); Cai, Miao (Guilin University of Electronic Technology); Yan, Haidong (Guilin University of Electronic Technology); Yu, Jiabing (Chongqing University); Liu, Mengyuan (Guilin University of Electronic Technology); He, Siliang (Guilin University of Electronic Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2024","Metal-oxide-semiconductor field-effect transistors (MOSFETs) undergo fatigue degradation under high thermal and electrical stresses. This process results in changes in their parasitic parameters, which can be detected using frequency domain reflectometry (FDR). Frequency domain impedance analysis is employed to characterize the various quality states of Si and SiC MOSFETs obtained from accelerated aging experiments. Results demonstrate a consistent increase in parasitic resistance as the devices degrade. By determining the drain-source parasitic resistance at the self-resonant frequency (f_ SRF) and the drain-source on-resistance for MOSFETs with varying degradation degrees, positive linear numerical fitting equations (14)-(15) are established to predict MOSFET degradation under zero DC bias voltage. In addition, FDR technology is used to identify the drain parasitic resistance at the f_ SRF of MOSFET samples with different sizes of defects in the sintered silver layer. These results reveal a positive correlation between the quality of the sintered silver layer and Rrm DSRF. The proposed approach is an effective quality screening technology for power semiconductor devices without requiring power-on treatment.","Aging degradation; Sintered silver layer; Defect; Two-port network; Parasitic resistance","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-12","","","Electronic Components, Technology and Materials","","",""
"uuid:e200c796-bf9b-47a5-91a6-2e5d99679ca3","http://resolver.tudelft.nl/uuid:e200c796-bf9b-47a5-91a6-2e5d99679ca3","Planning Regulations and Modelled Constraints in BIM: A Dutch Case Study","Koutamanis, A. (TU Delft Design & Construction Management)","","2024","Planning regulations determine a substantial part of buildings, but their constraints are usually not included in the setup of a BIM model or used explicitly for design guidance, but only tested in compliance checks once a model has been made. This is symptomatic of wider tendencies and ingrained biases that emphasize tacit knowledge and assume that information in a project starts from scratch—an assumption that runs contrary to predesign information ordering practices, as well as to the findings of creativity studies. In terms of process control, it negates important possibilities for feedforward. The paper proposes that BIM and design computerization, in general, should avoid the generate-and-test view of design, the view of design knowledge as tacit, and the adherence to analogue workflows, but develop, instead, approaches and workflows that keep information explicit and utilize it to frame design problems. To demonstrate this, we describe an exercise in which the expectation that the geometric representation of planning regulations returns permissible building envelopes was tested on the basis of a large number of cases produced by students who each collected planning regulations for a particular plot of land in the Netherlands and modelled their constraints in BIM, using a workflow that can be accommodated within the scope of predesign information gathering in any project. The results confirm that, for a large part of Dutch housing, the representation of planning regulations in BIM returns the permissible building envelope, and, so, forms a clear frame for subsequent design actions. They also suggest that including such information in the setup of a model is constructive and feasible, even for novices, and produces a bandwidth view of project information that integrates pre-existing information in a BIM workflow through feedforward. By extension, they also indicate a potential for a closer relation between analysis and synthesis in BIM, characterized by transparency and simultaneity, as well as the thorough understanding of problem constraints required for both efficiency and creativity.","constraints; feedforward; BIM; compliance; creativity","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:dae89161-a7f2-4fd6-88f8-7e73841aaf2d","http://resolver.tudelft.nl/uuid:dae89161-a7f2-4fd6-88f8-7e73841aaf2d","Optical signatures of charge- and energy transfer in TMDC/TMDC and TMDC/perovskite heterostructures","Gillespie, Sarah C. (AMOLF; TNO Energy Transition); van der Laan, Marco (Universiteit van Amsterdam); Poonia, D. (TU Delft ChemE/Opto-electronic Materials); Maiti, Sourav (Harwell Science and Innovation Campus, Didcot); Kinge, S.S. (TU Delft ChemE/Opto-electronic Materials; Toyota Motor Europe NV/SA); Siebbeles, L.D.A. (TU Delft ChemE/Opto-electronic Materials); Schall, Peter (Universiteit van Amsterdam)","","2024","Heterostructures (HSs) based on two-dimensional transition metal dichalcogenides (TMDCs) are highly intriguing materials because of the layers’ pronounced excitonic properties and their nontrivial contributions to the HS. These HSs exhibit unique properties that are not observed in either of the constituent components in isolation. Interlayer excitons (IEs), which are electron-hole pairs separated across the HSs, play a central role in determining these HS properties and are of interest both fundamentally and for device applications. In recent years, a major focus has been on understanding and designing HSs composed of two or more TMDC materials. Less attention has been paid to HSs composed of one TMDC layer and a layer of perovskite material. A central challenge in the understanding of HS properties is that basic measurements such as optical spectroscopic analysis can be misinterpreted due to the complexity of the charge transfer dynamics. Addressing these aspects, this review presents an overview of the most common and insightful optical spectroscopic techniques used to study TMDC/TMDC and TMDC/halide perovskite HSs. Emphasis is placed on the interpretation of these measurements in terms of charge transfer and the formation of IEs. Recent advances have started to uncover highly interesting phenomena, and with improved understanding these HSs offer great potential for device applications such as photodetectors and miniaturized optics.","2D materials; excitons; heterostructures; optical spectroscopy; perovskites","en","review","","","","","","","","","","","ChemE/Opto-electronic Materials","","",""
"uuid:335b6b68-3198-463c-967c-46153c8712e4","http://resolver.tudelft.nl/uuid:335b6b68-3198-463c-967c-46153c8712e4","An adaptive network model for AI-assisted monitoring and management of neonatal respiratory distress","Mokadem, Nisrine (Vrije Universiteit Amsterdam); Jabeen, F. (TU Delft Safety and Security Science); Treur, J. (Vrije Universiteit Amsterdam); Rob Taal, H. (Erasmus MC); Roelofsma, P.H.M.P. (Erasmus MC)","","2024","This article presents the use of second-order adaptive network models of hospital teams consisting of doctors and nurses, interacting together. A variety of scenarios are modelled and simulated, in relation with respiratory distress of a neonate, along with the integration of an AI-Coach for monitoring and support of such teams and of organizational learning. The research highlights the benefits of introducing a virtual AI-Coach in a hospital setting. The practical application setting revolves around a medical team responsible for managing neonates with respiratory distress. In this setting an AI-Coach act as an additional team member, to ensure correct execution of medical procedure. Through simulation experiments, the adaptive network models demonstrate that the AI-Coach not only aids in maintaining correct medical procedure execution but also facilitates organizational learning, leading to significant improvements in procedure adherence and error reduction during neonatal care.","Adaptive network; AI-Coach; Hospital teams; Organizational learning; Respiratory distress","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:bb71f599-d581-477d-842f-d1e89e6ed35e","http://resolver.tudelft.nl/uuid:bb71f599-d581-477d-842f-d1e89e6ed35e","The first mile towards access equity: Is on-demand microtransit a valuable addition to the transportation mix in suburban communities?","Liezenga, A. M. (Student TU Delft); Verma, T. (TU Delft Policy Analysis); Mayaud, J. R. (Spare Labs Inc.); Aydin, N.Y. (TU Delft System Engineering); van Wee, G.P. (TU Delft Transport and Logistics)","","2024","As cities grow, the benefits of living in them are increasingly unequally distributed. USA cities, in particular, have experienced rapid suburbanization of poverty and decreased levels of access to jobs for transit-dependent and vulnerable communities. The public transit challenges in suburbs call for innovative forms of transit to turn the tide on urban inequality. On-demand microtransit, a novel type of shared mobility provides efficient, convenient and affordable transportation. Its potential for redressing inequity had yet to be investigated fully in a suburban setting. We presented a case study from the suburbs of Minneapolis-St. Paul in Minnesota, USA. We combined unique datasets of microtransit ridership from two public transit agencies, transit surveys, land use data, and expert interviews, to conduct spatial analysis, accessibility analysis, and equity impact assessments for these suburbs. We found that microtransit enables public transit agencies to reach a larger number of vulnerable riders than fixed-route transit, particularly for commuting and trips to/from commercial areas. Microtransit also provided a cheaper alternative to ride-hailing and a faster alternative to public transit and walking, without cannibalizing ridership from fixed-rout transit alternatives. Finally, microtransit redressed transportation inequities by alleviating access inequality, reaching vulnerable rider groups effectively, and creating travel opportunities that are less spatially concentrated than those provided by traditional, fixed-route public transit. This study provided a framework for further investigations into the impact of microtransit, including in urban core or rural settings, and highlighted the impact of microtransit in reducing access inequity in a suburban environment.","Access equity; Accessibility; Microtransit; On-demand transit; Urban inequality","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:e838d8a4-9d95-4c81-9131-06874e6626be","http://resolver.tudelft.nl/uuid:e838d8a4-9d95-4c81-9131-06874e6626be","Simulation–optimization configurations for real-time decision-making in fugitive interception","van Droffelaar, I.S. (TU Delft Policy Analysis); Kwakkel, J.H. (TU Delft Policy Analysis); Mense, Jelte P. (Universiteit Utrecht); Verbraeck, A. (TU Delft Policy Analysis)","","2024","Simulation–optimization models are well-suited for real-time decision-support to the control room for search and interception of fugitives by Police on a road network, due to their ability to encode complex behavior while still optimizing the interception. The typical simulation–optimization configuration is simulation model optimization, where the simulation model describes the system to be optimized, and the optimizer attempts to find the combination of decision variables that maximizes the interception probability. However, the repeated evaluation of the simulation model leads to high computation time, thus rendering it inadequate for time-constrained decision contexts. To support police interception operations in real-time, timely calculation of the solution is essential. Sequential simulation–optimization, where the simulation model, with its rich behavior, constructs (part of) the constraints of an optimization problem, could decrease the computation time. We compare the computation time for two configurations of simulation–optimization (typical simulation model optimization and sequential simulation–optimization) for various problem instances of the fugitive interception problem. We show that sequential simulation–optimization reduces the computation time of large instances of the fugitive interception case study ten-fold. This result illustrates the potential of sequential simulation–optimization to mitigate the expensive optimization of simulation models.","Emergency service optimization; Fugitive interception; Real-time optimization; Search problem; Simulation–optimization","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:cd301a7a-f297-48f6-b519-2bc607554670","http://resolver.tudelft.nl/uuid:cd301a7a-f297-48f6-b519-2bc607554670","Adoption of renewable heating systems and thermal energy communities in the Netherlands: An empirical study","Okur, Ö. (TU Delft System Engineering); Fiori, Francesco (Universiteit Utrecht); Fouladvand, Javanshir (Universiteit Utrecht)","","2024","Renewable heating systems (RHS), such as solar thermal, geothermal, heat pumps, wood pellets, biomass, are essential to reduce dependence on fossil fuel-based heating systems and resulting CO2 emissions. Despite their benefits in terms of CO2 emissions, the widespread adoption of RHS has yet to be achieved. This paper aims to get insights into the intention to adopt RHS in the Netherlands For this purpose, it designs and conducts a survey based on the extended version of the theory of planned behavior, with five components: attitude, subjective norms, perceived behavioral control, personal norms, and descriptive norms. The survey also includes questions on participation in a thermal energy community. The results show that several factors affect individuals’ intention to adopt RHS. Many individuals in the Netherlands have a positive attitude toward adopting RHS, which is primarily caused by environmental concerns and wanting energy independence for their country. However, the majority of individuals think that they do not have the knowledge, financial means, or time to adopt RHS. Also, individuals who feel strong moral values and responsibilities are more likely to adopt RHS. Most individuals are willing to participate in a thermal energy community, and prefer participating in an energy community over adopting RHS individually. Based on these insights, a number of recommendations are made to stimulate the adoption of RHS in the Netherlands, such as taking into account moral norms, introducing policies to incentivize thermal energy communities, and addressing issues of injustice.","Energy behavior; Energy community; Energy transition; Renewable heating; Survey; Theory of planned behavior","en","journal article","","","","","","","","","","","System Engineering","","",""
"uuid:fdba7bc4-b62f-4c9d-af82-eaec30a067ea","http://resolver.tudelft.nl/uuid:fdba7bc4-b62f-4c9d-af82-eaec30a067ea","Vibration-Induced Discomfort in Vehicles: A Comparative Evaluation Approach for Enhancing Comfort and Ride Quality","Kat, C. (University of Pretoria); Skrickij, Viktor (Vilnius Gediminas Technical University); Shyrokau, B. (TU Delft Intelligent Vehicles); Kojis, Paulius (Vilnius Gediminas Technical University); Dhaens, Miguel (Tenneco Automotive Europe); Mantovani, Sara (Università Degli Studi di Modena e Reggio Emilia); Gherardini, Francesco (Università Degli Studi di Modena e Reggio Emilia); Strano, Salvatore (Università degli Studi di Napoli Federico II); Terzo, Mario (Università degli Studi di Napoli Federico II); Fujimoto, Hiroshi (University of Tokyo); Sorniotti, Aldo (University of Surrey); Camocardi, Pablo (Arrival Ltd.); Victorino, Alessandro Corrêa (Universite de Technologie de Compiegne); Ivanov, Valentin (Ilmenau University of Technology)","","2024","This article introduces a methodology for conducting comparative evaluations of vibration-induced discomfort. The aim is to outline a procedure specifically focused on assessing and comparing the discomfort caused by vibrations. The article emphasizes the metrics that can effectively quantify vibration-induced discomfort and provides insights on utilizing available information to facilitate the assessment of differences observed during the comparisons. The study also addresses the selection of appropriate target scenarios and test environments within the context of the comparative evaluation procedure. A practical case study is presented, highlighting the comparison of wheel corner concepts in the development of new vehicle architectures. Currently, the evaluation criteria and difference thresholds available allow for comparative evaluations within a limited range of vehicle vibration characteristics.","Comfort; Comparative evaluation; Ride; Vehicle vibration","en","journal article","","","","","","","","","","","Intelligent Vehicles","","",""
"uuid:08381070-d0b5-442b-85e2-cd5d5590aa3b","http://resolver.tudelft.nl/uuid:08381070-d0b5-442b-85e2-cd5d5590aa3b","Forecasting electricity demand of municipalities through artificial neural networks and metered supply point classification","Mateo-Barcos, S. (Universitat Politécnica de Valencia); Ribo-Perez, D.G. (TU Delft Energie and Industrie; Universitat Politécnica de Valencia); Rodríguez-García, J. (Universitat Politécnica de Valencia); Alcázar-Ortega, M. (Universitat Politécnica de Valencia)","","2024","This study develops a methodology to characterise and forecast large consumers’ electricity demand, particularly municipalities, with hundreds of different metered supply points based on the previous characterisation of facilities’ consumption. Demand forecasting allows consumers to improve their participation in electricity markets and manage their electricity consumption. The method considers a classification by different types of metered supply points combined with artificial neural networks to obtain hourly forecasts using well-known parameters such as day types, hourly temperature, the last hour of electricity consumption, and sunrise and sunset time. We apply the methodology to the municipality of Valencia using over five hundred hourly load profiles for a year during 2017 and 2018. Our results present aggregated forecasts with a maximum Mean Absolute Percentage Error of 3.8% per day, outperforming the same forecast without classifying Metered Supply Points. We conclude that a correct electricity demand forecast for a consumer with different types of consumption does not need submetering, but characterising Metered Supply Points is an option with lower costs that allows for better predictions.","Artificial neural networks; Load forecasting; Metered supply points; Municipalities","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:c1a3d267-c635-455f-9f1a-cbcab658e97c","http://resolver.tudelft.nl/uuid:c1a3d267-c635-455f-9f1a-cbcab658e97c","Assessing the influence of street canyon shape on aircraft noise: Results from measurements in courtyards near Amsterdam Schiphol Airport","Lugten, Martijn (TU Delft Environmental Technology and Design; Amsterdam Institute for Advanced Metropolitan Solutions (AMS)); Wuite, F.G.E. (TU Delft Environmental & Climate Design; Amsterdam Institute for Advanced Metropolitan Solutions (AMS)); Peng, Zhikai (TU Delft Environmental & Climate Design; Amsterdam Institute for Advanced Metropolitan Solutions (AMS)); Tenpierik, M.J. (TU Delft Environmental & Climate Design)","","2024","Aircraft noise is a major stressor for communities in the vicinity of airports. Aircraft noise prediction models omit the built environment, based on an implicit assumption that the impact of buildings on the propagation of aircraft noise is neglectable. In this article a study is presented in which aircraft noise levels were measured near walls facing towards and away from aircraft flyovers in an urban test environment near Amsterdam Schiphol Airport. The test environment comprises three adjacent courtyards, each enclosed by stacked shipping containers. To examine the influence of street geometry on aircraft noise, specifically for slanted roofs and building insets, the shipping containers were stacked in a different pattern around each courtyard. In total, sound levels for 2383 aircraft flyovers were analysed across five months at ten microphone positions within the courtyards, for both arrivals and departures. Depending on the geometry of the courtyards, mean differences (LA,max) between facades with- and without a line of sight towards the aircraft ranged between −1,3dBA and 5,0dBA for arrivals, and 8,7dBA and 13,6dBA for departures. SEL values ranged between between −0,8dBA and 4,3dBA for arrivals, and 8,1dBA and 11,6dBA for departures. The results suggest that slanted roofs perpendicular to the flight direction deflect incident sound, substantially reducing the sounds levels inside courtyards. Contrarily, building insets at building sides facing away from the flight paths did not reduce sound levels underneath the overhangs significantly. The findings stress the importance of architectural and urban design to mitigate aircraft noise.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-16","","","Environmental Technology and Design","","",""
"uuid:97aae2be-6332-4127-a4b5-e9d3730d4420","http://resolver.tudelft.nl/uuid:97aae2be-6332-4127-a4b5-e9d3730d4420","Assessing distracted driving crash severities at New York City urban roads: A temporal analysis using random parameters logit model","Rejali, Sina (Queensland University of Technology); Aghabayk, Kayvan (University of Tehran); Seyfi, Mohammad Ali (University of Tehran); Oviedo-Trespalacios, O. (TU Delft Safety and Security Science)","","2024","Distracted driving poses one of the most significant risks to road safety. The current study aims to provide a deeper understanding of the factors affecting the severity of distracted driving crashes in New York City and to explore the temporal stability in the effects of different variables on crash outcomes in 2016 to 2019 period by adopting a post-crash perspective. The police-reported data of single-vehicle distraction-related crashes of private cars on urban roads of New York City was used for this study. Three injury categories were considered: no injury, minor injury, and severe injury. To investigate crash severities and identify unobserved heterogeneities, a random parameters logit model was conducted. The results revealed that a wide variety of variables including driver traits, vehicle and temporal characteristics, and crash attributes were found to be significant in explaining distracted-related crash severities. Furthermore, a series of likelihood ratio tests were conducted to identify the temporal shifts of estimated variables during the period. The results of the temporal analysis showed that the estimated variables of the random parameters model were unstable during the 4-year period, which may be the result of shifting trends such as the development of in-vehicle technologies, and new sources of distraction. However, the complex nature of distracted-related crashes and changes in driver behavior should be considered for further interpretation. This research provides a set of policy implications for planners and policymakers, aiming at facing factors contributing to a higher level of injury severity in distracted driving crashes. This includes providing targeted information on distracted driving to high-risk groups, such as younger drivers, and also combining education, awareness programs, higher penalties, and intense patrolling. Engineering measures such as enhanced roadside illumination and audible edge lines can be effective, especially in reducing late-night distracted driving crashes.","Crash severity; Distracted driving; Multitasking; Random parameters logit; Temporal assessment","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:8ce9eeba-daee-444e-8b3d-2d302f7e7aff","http://resolver.tudelft.nl/uuid:8ce9eeba-daee-444e-8b3d-2d302f7e7aff","Non-unit protection method for MMC-HVDC grids based on selective drop rate of voltage traveling waves","Dehghan Marvasti, F. (TU Delft Intelligent Electrical Power Grids; Yazd University); Mirzaei, Ahmad (Yazd University); Savaghebi, Mehdi (Technical University of Denmark); Lekić, A. (TU Delft Intelligent Electrical Power Grids); Popov, M. (TU Delft Intelligent Electrical Power Grids)","","2024","Fast, sensitive, and selective protection principles are one of the major challenges in the feasibility of modular multi-terminal (MMC) high voltage direct current (HVDC) grids. Rate of change of voltage (ROCOV) and transient-based solutions are the traditional and widely accepted protection principles. Despite the speed and practicality of these solutions, they generally suffer from sensitivity and selectivity issues, particularly when dealing with high-resistance faults and low-size current limiting inductors (CLIs). To improve upon these methods, this paper proposes a new primary protection method that utilizes a selective drop rate of fault-generated voltage traveling waves (TW) to detect internal DC line faults. This is achieved by a comprehensive analysis of the line-mode fault-generated voltage (LFGV) under various internal and external fault scenarios. As the key fault characteristics, the proposed method exploits the minimum points of initial LFGV and the corresponding time to form the basis of the proposed protection method. The effectiveness of this approach is evaluated using a four-terminal MMC-HVDC grid in PSCAD/EMTDC. Compared to ROCOV and transient-based solutions, the proposed method identifies internal faults up to 1250 Ω with fast response, while maintaining its practicality and independence to CLI size.","Fault-generated voltage traveling wave; MMC-HVDC protection; Primary protection; Traveling wave protection","en","journal article","","","","","","","","","","","Intelligent Electrical Power Grids","","",""
"uuid:a928473c-d020-43d2-8df7-6bf4f1b77656","http://resolver.tudelft.nl/uuid:a928473c-d020-43d2-8df7-6bf4f1b77656","A fatigue test based on inclined loading block concept to benchmark delamination growth considering loading history and R-curve effect","Leciñana, I. (Basque Research and Technology Alliance (BRTA); University of Girona); Renart, J. (University of Girona; Generalitat de Catalunya); Carreras, L. (University of Girona); Turon, A. (University of Girona); Zurbitu, J. (Basque Research and Technology Alliance (BRTA)); Tijs, B.H.A.H. (TU Delft Group De Breuker; Fokker/GKN Aerospace)","","2024","The main objective of this paper is to present a delamination benchmark test concept for composite materials that develop non-self-similar delamination in characterization specimens. The non-self-similar delamination is induced by rotating the loading blocks. The simplicity of the test allows for analyzing the loading mode history by concatenating different loading conditions, such as static and fatigue loading, under multiple loading modes. The methodology introduced in this paper can be particularized for any given composite material set and any sequence of loading conditions. To demonstrate the capabilities of the benchmark test, a case study is presented using AS4D/PEKK-FC thermoplastic composite material, which exhibits strong R-curve behavior. A sequence of opening and shear failure modes was applied under static and fatigue loading, providing an experimental data set that is ready to be used as a part of the validation of numerical predictive delamination models. The delamination process was monitored by X-ray radiography, and the final fracture surfaces were analyzed with scanning electron microscopy (SEM), giving a physical insight into the contribution of the fracture mechanisms to the delamination process.","Benchmark validation test; Delamination process zone; Fatigue; Loading history; R-curve effect","en","journal article","","","","","","","","","","","Group De Breuker","","",""
"uuid:3d80ec96-b531-4a44-8370-aa0f8351ef0f","http://resolver.tudelft.nl/uuid:3d80ec96-b531-4a44-8370-aa0f8351ef0f","Feller property of regime-switching jump diffusion processes with hybrid jumps","Blom, H.A.P. (TU Delft Air Transport & Operations)","","2024","Abstract.: The transition kernel of an ℝn-valued diffusion or jump diffusion process {Xt} is known to satisfy the Feller property if {Xt} is the solution of an SDE whose coefficients are Lipschitz continuous. This Lipschitz route to Feller falls short if {Xt} is the solution of an SDE whose coefficients depend on a state-dependent regime-switching process {θt}. In this paper it is shown that pathwise uniqueness and the Feller property are satisfied under mild conditions for a regime-switching jump diffusion process {Xt, θt} with hybrid jumps, i.e. jumps in {Xt} that occur simultaneously with {θt} switching.","Feller property; hybrid jumps; hybrid state Markov process; Itô-Skorohod stochastic differential equation; strong solution","en","journal article","","","","","","","","","","","Air Transport & Operations","","",""
"uuid:babfba63-0db1-4d72-96f7-0fad23ca4b7f","http://resolver.tudelft.nl/uuid:babfba63-0db1-4d72-96f7-0fad23ca4b7f","In Situ XPS Analysis of Tribo-chemical Behavior in Titanium Alloy Exposed to Fretting Wear Under the Vacuum Environments","Long, Jianjun (Southwest Jiaotong University); Wei, Xuejiao (Southwest Jiaotong University); Dong, Yiting (Southwest Jiaotong University); Cheng, Xixi (Southwest Jiaotong University); Li, Hao (Southwest Jiaotong University); Xu, X. (TU Delft Novel Aerospace Materials; Southwest Jiaotong University); Zhu, Minhao (Southwest Jiaotong University)","","2024","A systematic experimental investigation concerning the fretting-induced tribo-chemical state and its effect on the fretting wear behavior of titanium alloys under the vacuum atmospheres (4 × 10–3 Pa and 4 × 10–1 Pa) in different fretting regimes is reported. An in situ XPS analysis tester was developed to capture the real tribo-chemical state of worn surface for all test conditions. Results show that samples subjected to different vacuum atmospheres have varied tribo-chemical states depending on the fretting regime, which play significantly different roles in determining the associated damage mechanisms and the resulting fretting wear resistance. Under both vacuum atmospheres, in the partial slip regime (PSR) the worn scars were mainly covered by TiO2, showing comparable levels of very slight damage, while in the mixed fretting regime (MFR), the tribo-layer is still mainly consisted of TiO2, but with an evident peak of Ti metal for the high vacuum degree (4 × 10–3 Pa) in MFR, showing a mild damage. In contrast, in the gross slip regime (GSR), Ti metal was prone to be oxidized to Ti2O3 and TiO on the worn scar, especially for the low vacuum degree (4 × 10–1 Pa) having a highest content of Ti2O3. It might be inferred that the tribo-layer containing more Ti2O3 formed during fretting wear process is susceptible to be broken, hence showing a highest fretting wear volume in GSR for the low vacuum degree. The results suggest that for the vacuum environments, the Ti6Al4V may be more suitable to be used under the high vacuum atmosphere.","Fretting wear; In situ XPS; Titanium alloy; Tribo-chemical state; Vacuum atmosphere","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-10-01","","","Novel Aerospace Materials","","",""
"uuid:f1f475c2-f92c-4b5c-9f14-f06ca10180af","http://resolver.tudelft.nl/uuid:f1f475c2-f92c-4b5c-9f14-f06ca10180af","Does the Rubber Meet the Road?: Assessing the Potential of Devulcanization Technologies for the Innovation of Tire Rubber Recycling","Roetman Roetman, E.C. (TU Delft Design for Sustainability; Windesheim University of Applied Sciences); Joustra, J.J. (TU Delft Design for Sustainability); Heideman, Geert (Windesheim University of Applied Sciences); Balkenende, R. (TU Delft Design for Sustainability)","","2024","Innovation is crucial to meet the circular economy goals for tire recycling. Devulcanization, an innovative recycling method of reprocessing tire rubber, offers a pathway towards achieving circular economy objectives. While previous research on devulcanization has primarily focused on technical aspects, this study shifts the focus towards identifying opportunities and barriers for innovation through devulcanization. This research utilizes the Technological Innovation System framework as a basis to analyze the dynamics of innovation within value chains and innovation networks. Across Europe, 36 organizations were identified that develop and utilize devulcanization to transform rubber from end-of-life tires into a valuable resource for new rubber products. In this study, a semi-structured in-depth interview approach was applied to interview 12 organizations that have developed or utilize technologies for the devulcanization of tire rubber. It was found that the development of various devulcanization approaches for diverse types of products has created opportunities for upscaling. To capitalize on these opportunities, organizations need to collaborate throughout the entire value chain of tire production and recycling. Achieving this collaboration requires interventions across the industry.","circular economy; recycling; devulcanization; technological innovation systems (TIS); tires; rubber","en","journal article","","","","","","","","","","","Design for Sustainability","","",""
"uuid:24c152a8-1d54-4fce-ad0b-c505b481c7e7","http://resolver.tudelft.nl/uuid:24c152a8-1d54-4fce-ad0b-c505b481c7e7","Constructing and storytelling: accommodating different play orientations in learning spatial thinking","Sonneveld, L.T. (TU Delft Industrial Design Engineering); Klapwijk, R.M. (TU Delft Science Education and Communication); Stappers, P.J. (TU Delft Design Conceptualization and Communication)","","2024","Spatial ability is malleable and belongs in the preschool. For preschoolers, many analytical activities with one correct answer such as tangram have been developed. Less is known about employing open-ended design assignments to creatively practice spatial thinking. Little attention has been paid to the mutual qualitative differences between children when engaged in spatial thinking and insight in children’s motivation is lacking. As design and play have much in common, our first study investigated play orientations during free play of 49 Dutch preschoolers during free play in a low and a high SES school. Participative interviews and observations in the construction and home corners of two schools uncovered different play orientations– construction and pretend play - and either a focus on open-ended objects or on defined objects. In a subsequent study, the influence of these play and object orientations on how children design was investigated. This study with 13 children also used generative design research methods grounded in ethnographic research and therapeutic practices. Using an empathic, story-based, open-ended design challenge, results showed that play-orientations of children influence the length and nature of the design activities as well as the design outcomes. Children with a pretend-play orientation are longer engaged and talk more about the character involved. They usually built organic structures with a variety of objects, while construction-oriented children mainly built sturdy and geometrical structures and mainly used open-ended objects. In all play orientations, spatial thinking was practiced and children were spatially challenged. For example, in all orientations difficulties arose around getting the character in out the structure, however, as different structures were build, the nature of these difficulties were also different. Open-ended design activities that contain characters and problems children can empathize with are a valuable addition to the palette of activities to develop spatial thinking in early classrooms. Our study shows that design activities stimulate children to practice spatial thinking in a creative context and have the ability to engage children with a pretend-play orientation who are otherwise less engaged in construction. The play-orientations and object-orientations are informative for research and the development of spatial educational interventions aiming at a diversity of learners.","spatial thinking; design and technology education,; construction play; empathy; preschool; pretend play; storytelling,; generative design research","en","journal article","","","","","","","","","Industrial Design Engineering","","Science Education and Communication","","",""
"uuid:0f5ac119-2bed-47e0-89b1-d74240787bd3","http://resolver.tudelft.nl/uuid:0f5ac119-2bed-47e0-89b1-d74240787bd3","Personalized anomaly detection in PPG data using representation learning and biometric identification","Ghorbani, R. (TU Delft Pattern Recognition and Bioinformatics); Reinders, M.J.T. (TU Delft Pattern Recognition and Bioinformatics); Tax, D.M.J. (TU Delft Pattern Recognition and Bioinformatics)","","2024","Photoplethysmography (PPG) signals, typically acquired from wearable devices, hold significant potential for continuous fitness-health monitoring. In particular, heart conditions that manifest in rare and subtle deviating heart patterns may be interesting. However, robust and reliable anomaly detection within these data remains a challenge due to the scarcity of labeled data and high inter-subject variability. This paper introduces a two-stage framework leveraging representation learning and personalization to improve anomaly detection performance in PPG data. The proposed framework first employs representation learning to transform the original PPG signals into a more discriminative and compact representation. We then apply three different unsupervised anomaly detection methods for movement detection and biometric identification. We validate our approach using two different datasets in both generalized and personalized scenarios. Our results demonstrate significant improvements: for movement detection, in the generalized scenario, AUCs improved from barely 0.5 to above 0.9 with representation learning. Importantly, inter-subject variability was substantially reduced, from around 0.4 to below 0.1. In the personalized scenario, AUCs became close to 1.0, with variability further reduced to below 0.05, indicating the effectiveness of both representation learning and personalization for anomaly detection in PPG data. Similar enhancements were observed in biometric identification, emphasizing how our approach can minimize inter-subject variability and enhance PPG-based health monitoring systems.","Anomaly detection; Isolation forest; Multivariate normal distribution; PCA reconstruction; PPG; Representation learning","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:734bcb18-c0d0-40f9-a0eb-795099742431","http://resolver.tudelft.nl/uuid:734bcb18-c0d0-40f9-a0eb-795099742431","Investigation of coherent Fourier scatterometry as a calibration tool for determination of steep side wall angle and height of a nanostructure","Paul, A. (TU Delft ImPhys/Pereira group); Rafigh Doost, J. (TU Delft ImPhys/Pereira group); Dou, X. (TU Delft ImPhys/Pereira group); Pereira, S.F. (TU Delft ImPhys/Pereira group)","","2024","Nanostructures with steep side wall angles (swa) play a pivotal role in various technological applications. Accurate characterization of these nanostructures is crucial for optimizing their performance. In this study, we propose a far-field detection method based on coherent Fourier scatterometry (CFS) for accurate quantification of steep swa and heights in cliff-like nanostructures. Our approach introduces a parameter termed ‘visibility’, derived from the unique far-field signatures of cliff-like nanostructures. This parameter serves as a quantitative metric for the calibration of swa and heights. The heightened sensitivity of our method is demonstrated, particularly when the incident polarization is perpendicular to the invariant direction of the nanostructure for swa calibration, while both polarization states exhibit sensitivity to height calibration. Furthermore, a comprehensive sensitivity analysis reveals the stable nature of our method, showcasing that even with fluctuations of ±10 nm in the position of the nanostructure, the resulting swa remains stable within a range of ±0.5◦. The exponential variation of the visibility parameter with edge roundness is observed, with fluctuations in edge roundness within 10 nm resulting in swa variations within 1.7◦ for both polarization states. In experimental validations, our results demonstrate reasonable agreement between CFS-derived and AFM measurements. The AFM data for swa (77.99◦ ±1.37◦) and height (148.35 nm ±2.11 nm) are corroborated with CFS-derived value of swa (77.75◦ ±3.61◦, 78.36◦ ±3.89◦) and height (149.42 nm ±1.66 nm, 150.05 nm ±1.04 nm) obtained from calibration curves for TM and TE incident beams, respectively. Overall, our findings underscore CFS as a potential and reliable tool for nanostructure characterization, offering precise measurements that are pivotal for advancing nanotechnology.","steep side wall angle; coherent Fourier scatterometry; calibration","en","journal article","","","","","","","","","","","ImPhys/Pereira group","","",""
"uuid:9cb80a42-6a7c-4b3e-8718-f48d5edc0e91","http://resolver.tudelft.nl/uuid:9cb80a42-6a7c-4b3e-8718-f48d5edc0e91","Padé approximants of the Born series of electromagnetic scattering by a diffraction grating","van der Sijs, T.A. (TU Delft ImPhys/El Gawhary group); El Gawhary, O. (TU Delft ImPhys/El Gawhary group); Urbach, Paul (TU Delft ImPhys/Stallinga group)","","2024","We present the realization of a vectorial perturbation method based on the Born series applied to strong electromagnetic scattering problems. We present the general theoretical formalism and show a semianalytical implementation for scattering by diffraction gratings. We are particularly interested in the strong scattering regime, where the Born series is known to wildly (namely, exponentially) diverge. By applying Padé approximation to the vectorial Born series, we are able to obtain accurate results from divergent Born series. The method we present has the inherent benefit of being close to the actual physical mechanism behind the formation of a scattered signal, as the solution is built step by step from a sequence of multiple-scattering events. This helps in the understanding of signal formation, which is a key element in inverse scattering problems that are relevant to optical metrology, among others.","","en","journal article","","","","","","","","","","","ImPhys/El Gawhary group","","",""
"uuid:d87848db-7017-4c23-93a8-d53a32017338","http://resolver.tudelft.nl/uuid:d87848db-7017-4c23-93a8-d53a32017338","Bridging HRI Theory and Practice: Design Guidelines for Robot Communication in Dairy Farming","Cila, N. (TU Delft Human Information Communication Design); Gonzalez Gonzalez, I. (TU Delft Industrial Design Engineering); Jacobs, Jan (Lely, Maassluis); Rozendaal, M.C. (TU Delft Human Information Communication Design)","","2024","Using HRI theory to inform robot development is an important, but difficult, endeavor. This paper explores the relationship between HRI theory and HRI practice through a design project on the development of design guidelines for human-robot communication together with a dairy farming robot manufacturer. The design guidelines, a type of intermediate-level knowledge, were intended to enrich the specialized knowledge of the company on farming context with relevant academic knowledge. In this process, we identified that HRI theories were used as a frame, a tool, best practices, and a reference; while the HRI practice provided a context, a reference, and validation for the theories. Our intended contribution is to propose a means to facilitate exchanges both ways between HRI theory and practice and add to the emerging repertoire of designerly ways of producing knowledge in HRI.","Dairy farming; Design guidelines; Intermediate-level knowledge; Research-practice gap; Robot development","en","conference paper","IEEE","","","","","","","","Industrial Design Engineering","","Human Information Communication Design","","",""
"uuid:ff5be262-5634-40d5-81e1-4b21a97bfc01","http://resolver.tudelft.nl/uuid:ff5be262-5634-40d5-81e1-4b21a97bfc01","On the Effects of Automatically Generated Adjunct Questions for Search as Learning","Zhu, P. (TU Delft Web Information Systems); Câmara, Arthur (TU Delft Web Information Systems; Zeta Alpha); Roy, N. (TU Delft Web Information Systems); Maxwell, D.M. (TU Delft Web Information Systems; Booking.com B.V); Hauff, C. (TU Delft Web Information Systems; Spotify)","","2024","Actively engaging learners with learning materials has been shown to be very important in the Search as Learning (SAL) setting. One active reading strategy relies on asking so-called adjunct questions, i.e., manually curated questions geared towards essential concepts of the target material. However, manual question creation is impractical given the vast online content. Recent research has explored the effects of Automatic Question Generation (AQG) on aiding human learning. These studies have primarily focused on user studies in controlled online reading scenarios with limited documents. However, the impacts of adjunct questions on learning in the SAL setting, which involves learning through web searching, are not yet well understood. This paper addresses this gap by conducting a user study with automatically generated adjunct questions integrated into the reading interface built on top of a search system. We conducted a between-subjects user study (N = 144) to investigate the incorporation of automatically generated adjunct questions on participants' learning. We employed three different question generation strategies as well as a control condition: (i) synthesis questions; (ii) factoid questions targeting random text spans; and (iii) factoid questions targeting terms and phrases relevant to the information need at hand. We present four major findings: (i) participants who received adjunct questions exhibited significantly more fine-grained reading behaviour, such as longer document dwell time and more scrolls, than those without adjunct questions. However, adjunct questions' influence on learning outcomes depends on the AQG strategy. (ii) Question types significantly influence participants' reading behaviour. (iii) The adjunct questions' target spans significantly influence learning outcomes. Lastly, (iv) participants' prior knowledge levels affect adjunct questions' effects on their learning outcomes and their reaction to different AQG strategies. Our findings have significant design implications for learning-oriented search systems. The data and code is available at https://github.com/zpeide/AQG-AdjunctQuestions.","","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Web Information Systems","","",""
"uuid:b9614a0e-dddb-41d6-aa2a-27ff6bd83e55","http://resolver.tudelft.nl/uuid:b9614a0e-dddb-41d6-aa2a-27ff6bd83e55","Geoelectrical and electromagnetic imaging methods applied to groundwater systems: recent advances and future potentials","Rulff, P. (TU Delft Applied Geophysics and Petrophysics; Uppsala University); Castillo-Reyes, Octavio (Universitat Politecnica de Catalunya; Barcelona Supercomputing Center); Koyan, Philipp (University of Potsdam); Martin, Tina (Lund University); Deleersnyder, Wouter (Katholieke Universiteit Leuven; Universiteit Gent); Carrizo Mascarell, M.E. (TU Delft Applied Geophysics and Petrophysics)","","2024","The impacts of climate change, combined with population growth, necessitate practical and effective solutions for locating groundwater resources and ensuring drinking water quality. Our contribution explores recent advances in geoelectrical and electromagnetic imaging methods applied to investigate groundwater systems. Geoelectrical and electromagnetic imaging techniques are popular methods for characterising subsurface properties, such as electrical resistivity or dielectric permittivity. These electrical properties are strongly related to the hydrogeological characteristics of the subsurface. Therefore, geoelectrical and electromagnetic investigations can provide valuable insights into finding groundwater resources, assessing the water quality in terms of contaminations and conducting effective groundwater management.
Our study examines state-of-the-art approaches in modelling and instrumentation of induced polarisation and electrical resistivity tomography, as well as time- and frequency-domain electromagnetics and ground-penetrating radar methods. We review recent impactful and innovative groundwater case studies where the above-mentioned methods were applied and further developed. Emphasising the combination of geoelectrical and electromagnetic methods, the studies provide insights into the variation of electrical subsurface properties at different scales, contributing to an improved understanding of the hydrological dynamics in the studied areas. Furthermore, we provide an outlook on the potential for applying geoelectrical and electromagnetic imaging techniques for large-scale groundwater investigations in the exascale computing area.","","en","abstract","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:eff1fd7e-5049-43aa-a6ad-c8702372d8da","http://resolver.tudelft.nl/uuid:eff1fd7e-5049-43aa-a6ad-c8702372d8da","BICEP: A Bio-Inspired Compliant Elbow Prosthesis","Castañeda, Theophil Spiegeler (Technische Universität München); Horstman, Bart (Student TU Delft); Capsi-Morales, Patricia (Technische Universität München); Della Santina, C. (TU Delft Learning & Autonomous Control; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Piazza, Cristina (Technische Universität München)","Piazza, Cristina (editor); Capsi-Morales, Patricia (editor); Figueredo, Luis (editor); Keppler, Manuel (editor); Schütze, Hinrich (editor)","2024","Adopting compliant structures holds the potential to enhance the robustness and interaction capabilities of the next generation of bionic limbs. Although researchers have proficiently explored this approach in the design of artificial hands, they devoted little attention to the development of more proximal joints. This work presents a compliant prosthetic elbow prototype called BICEP. The design incorporates compliant cross-axis flexural pivots that connect the upper and lower arm without direct contact between the two links. The actuation architecture, inspired by biological mechanisms, employs one actuator and two tendons to create an agonist-antagonist mechanism. This joint enables rotation along its flexion-extension axis while maintaining flexibility in out-of-plane directions, in a system with an overall weight of 351 g. A preliminary evaluation showcases lifting capacities supporting up to 2500 g, and a maximum speed of 157∘ per second across a 135∘ range of motion. The soft cross-axis flexural pivots exhibit compliant behavior in both the sagittal and transversal planes, enabling a pleasant interaction with the environment and ensuring safe absorption of unintentional impacts.","Bioinspired Systems; Compliant Mechanism; Soft Robotics; Upper Limb Prosthetics","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-10","","","Learning & Autonomous Control","","",""
"uuid:d11c6329-8f2f-46db-b338-3d2bc6928711","http://resolver.tudelft.nl/uuid:d11c6329-8f2f-46db-b338-3d2bc6928711","A Hybrid Control Approach for a Pneumatic-Actuated Soft Robot","Tavio Y Cabrera, E.J. (TU Delft Mechanical Engineering); Della Santina, C. (TU Delft Learning & Autonomous Control; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Borja, Pablo (Plymouth University)","Piazza, Cristina (editor); Capsi-Morales, Patricia (editor); Figueredo, Luis (editor); Keppler, Manuel (editor); Schütze, Hinrich (editor)","2024","The compliant nature of soft robots is appealing to a wide range of applications. However, this compliant property also poses several control challenges, e.g., how to deal with infinite degrees of freedom and highly nonlinear behaviors. This paper proposes a hybrid controller for a pneumatic-actuated soft robot. To this end, a model-based feedforward controller is designed and combined with a correction torque calculated via Gaussian process regression. Then, the proposed model-based and hybrid controllers are experimentally validated, and a detailed comparison between controllers is presented. Notably, the experimental results highlight the potential benefits of adding a learning approach to a model-based controller to enhance the closed-loop performance while reducing the computational load exhibited by purely learning strategies.","","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-10","Mechanical Engineering","","Learning & Autonomous Control","","",""
"uuid:745fcd7b-e679-4561-b9b2-90004a26a9ee","http://resolver.tudelft.nl/uuid:745fcd7b-e679-4561-b9b2-90004a26a9ee","Multi-objective Design and Benchmark of Wide Voltage Range Phase-Shift Full Bridge DC/DC Converters for EV Charging Application","Lyu, D. (TU Delft DC systems, Energy conversion & Storage); Soeiro, Thiago Batista (University of Twente); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2024","This article presents an analysis, multiobjective design, and benchmark of three modified 3 phase shift full-bridge (PSFB) converters that are well-suited for electric vehicle (EV) battery charging applications, covering both typical battery voltage classes (400 and 800 V). These three modified PSFB converters, denoted as the t-PSFB, r-PSFB, and i-PSFB converters, have the ability to reconfigure and provide better efficiency performance in the wide voltage range necessary for public EV battery charging applications. In this article, the characteristics and design considerations of these reconfigurable PSFB converters are discussed in detail. A multiobjective converter design process is proposed to optimize the average efficiency, normalized cost, and power density of the magnetic components and heat sinks. This design process employs the correlations between the cost and performance indexes of the key components derived based on open and accessible components' data to estimate the design objectives. In this way, the design process is not constrained by certain component choices, making it easier to identify the most advantageous design. A benchmark study is conducted among the reconfigurable PSFB topologies and the conventional PSFB circuit using the proposed multiobjective design process. To validate the analysis, a close-to-Pareto-front 11-kW, 45-kHz r-PSFB converter prototype with 640-840-V input voltage and 250-1000-V output voltage ranges is developed and tested.","DC/DC converter; electric vehicle (EV) charging; phase shift full bridge (PSFB); reconfiguration, wide voltage range","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-08","","","DC systems, Energy conversion & Storage","","",""
"uuid:576d1052-37ed-4375-85fe-65ce1b68aac2","http://resolver.tudelft.nl/uuid:576d1052-37ed-4375-85fe-65ce1b68aac2","Scaling towards the critical point in the combined reaction/Gibbs ensemble","Polat, H.M. (TU Delft Engineering Thermodynamics); Lasala, Silvia (Laboratoire Réactions et Génie des Procédés (LRGP)); De Meyer, Frédérick (TotalEnergies; Center for Thermodynamics of Processes (CTP)); Houriez, Céline (Center for Thermodynamics of Processes (CTP)); Moultos, O. (TU Delft Engineering Thermodynamics); Vlugt, T.J.H. (TU Delft Engineering Thermodynamics)","","2024","We explore the impact of force field parameters and reaction equilibrium on the scaling behavior towards the critical point in reactive binary systems, focusing on /. This system can be considered as a special single-component system since and are in chemical equilibrium via the chemical reaction . We simplify the system by representing both components as single LJ particles, achieving excellent agreement with densities computed using molecular simulations in which all-atom force fields were used. We investigate the effect of force field parameters (ɛ and ) on phase behavior and show that the critical exponent remains constant, which means that intermolecular interactions do not affect the scaling to the critical point when the chemical reaction takes place. We also investigate the sensitivity of the reaction equilibrium constant and show that even small changes in isolated molecule partition functions lead to large differences in chemical equilibria. We show that the critical exponent is different for systems with different reaction equilibrium constants, so a careful parameterization of is needed for an accurate computation of critical temperatures of reactive mixtures. We perform a screening of reactive binary mixtures for a wide range of ideal gas reaction equilibrium constants, revealing key insights into the thermodynamic behavior and critical properties. Thereby we facilitate the efficient screening of reactive binary mixtures for various applications. Our results emphasize the importance of accurately parameterizing and provide valuable insights into the critical scaling behavior of complex reactive systems.","Gibbs ensemble; Reaction ensemble; Monte Carlo simulations; Critical temperature; Critical density; Reactive mixtures","en","journal article","","","","","","","","","","","Engineering Thermodynamics","","",""
"uuid:91c67aef-aebb-4a65-8858-720f63d8ae8e","http://resolver.tudelft.nl/uuid:91c67aef-aebb-4a65-8858-720f63d8ae8e","“It takes a village to write a really good paper”: A normative framework for peer reviewing in philosophy","Copeland, S.M. (TU Delft Ethics & Philosophy of Technology); Marin, L. (TU Delft Ethics & Philosophy of Technology)","","2024","That there is a “crisis of peer review” at the moment is not in dispute, but sufficient attention has not yet been paid to the normative potential that lies in current calls for reform. In contrast to approaches to “fixing” the problems in peer review, which tend to maintain the status quo in terms of professionalising opportunities, this paper addresses the needs of philosophers and how peer-review reform can be an opportunity to improve the academic discipline of philosophy, whereby progress is understood as making the discipline more fair to the global academic community and more conducive to the flourishing of academic philosophers. The paper evaluates recent categories of relevant norms and correlating reforms. In conclusion, it recommends that philosophy pursue the norms of transparency and democracy explicitly when proposing peer-review reform and suggest that proposals for forum-based models of peer review are most likely to support those norms.","academic philosophy; fairness; flourishing; normativity; peer review","en","journal article","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:343f62fe-d09e-4c80-9ad1-44390f934cb5","http://resolver.tudelft.nl/uuid:343f62fe-d09e-4c80-9ad1-44390f934cb5","Biodegradation-affected fatigue behavior of extrusion-based additively manufactured porous iron–manganese scaffolds","Putra, N.E. (TU Delft Biomaterials & Tissue Biomechanics); Moosabeiki, Vahid (TU Delft Biomaterials & Tissue Biomechanics); Leeflang, M.A. (TU Delft Biomaterials & Tissue Biomechanics); Zhou, J. (TU Delft Biomaterials & Tissue Biomechanics); Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics)","","2024","Additively manufactured (AM) biodegradable porous iron-manganese (FeMn) alloys have recently been developed as promising bone-substituting biomaterials. However, their corrosion fatigue behavior has not yet been studied. Here, we present the first study on the corrosion fatigue behavior of an extrusion-based AM porous Fe35Mn alloy under cyclic loading in air and in the revised simulated body fluid (r-SBF), including the fatigue crack morphology and distribution in the porous structure. We hypothesized that the fatigue behavior of the architected AM Fe35Mn alloy would be strongly affected by the simultaneous biodegradation process. We defined the endurance limit as the maximum stress at which the scaffolds could undergo 3 million loading cycles without failure. The endurance limit of the scaffolds was determined to be 90 % of their yield strength in air, but only 60 % in r-SBF. No notable crack formation in the specimens tested in air was observed even after loading up to 90 % of their yield strength. As for the specimens tested in r-SBF, however, cracks formed in the specimens subjected to loads exceeding 60 % of their yield strength appeared to initiate on the periphery and propagate toward the internal struts. Altogether, the results show that the extrusion-based AM porous Fe35Mn alloy is capable of tolerating up to 60 % of its yield strength for up to 3 million cycles, which corresponds to 1.5 years of use of load-bearing implants subjected to repetitive gait cycles. The fatigue performance of the alloy thus further enhances its potential for trabecular bone substitution subjected to cyclic compressive loading. Statement of significance: Fatigue behavior of extrusion-based AM porous Fe35Mn alloy scaffolds in air and revised simulated body fluid was studied. The Fe35Mn alloy scaffolds endured 90 % of their yield strength for up to 3 × 106 loading cycles in air. Moreover, the scaffolds tolerated 3 × 106 loading cycles at 60 % of their yield strength in revised simulated body fluid. The Fe35Mn alloy scaffolds exhibited a capacity of withstanding 1.5-year physiological loading when used as bone implants.","Additive manufacturing; Biodegradable metal; Bone implant; Corrosion fatigue; Porous material","en","journal article","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:c5eaa0e0-4255-431e-b59b-45b14a222c08","http://resolver.tudelft.nl/uuid:c5eaa0e0-4255-431e-b59b-45b14a222c08","A Novel Reinforcement-Learning-Based Compensation Strategy for DMPC-Based Day-Ahead Energy Management of Shipboard Power Systems","Fu, J. (Dalian University of Technology; Dalian Maritime University); Sun, D. (TU Delft Transport and Planning); Peyghami, S. (Aalborg University); Blaabjerg, Frede (Aalborg University)","","2024","Distributed model predictive control (DMPC) has become a focus in the energy management of shipboard power systems due to its capabilities for privacy preservation, robustness, and distributing computing burdens to local processors. DMPC determines control actions in a distributed manner based on the predictions of system statuses. However, the performance of DMPC is affected by inaccurate predictions resulting from uncertain parameters in nominal prediction models. Particularly, these inaccuracies in predicting propulsion loads and solar panel generation powers can lead to power imbalances when implementing the control actions determined by DMPC. To address this challenge, this paper proposed a novel reinforcement learning compensated DMPC (RL-C-DMPC) to distributively compensate for the control actions determined by DMPC baseline control, thereby rectifying the power imbalances caused by uncertain parameters in nominal prediction models. A value-decomposition-network-based training and distributed testing mechanism is designed for our proposed RL-C-DMPC. Furthermore, a method for range selection of compensation rate is specifically proposed for the energy management of shipboard power systems. To validate the effectiveness of our proposed RL-C-DMPC, we conduct a comprehensive case study utilizing real-life voyage data and historical solar power generation data in the area of the voyage to build the environment for training and testing. By comparing power imbalances between DMPC and RL-C-DMPC, our results indicate significant reductions in power imbalances so that frequency stability can be better ensured. Furthermore, via the case study, we also evaluate the communication robustness of RL-C-DMPC.","Uncertainties; reinforcement learning; distributed control frameworks; distributed model predictive control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-27","","","Transport and Planning","","",""
"uuid:4b065eb9-ece4-44a0-bf9b-a8bdb6a7e9ec","http://resolver.tudelft.nl/uuid:4b065eb9-ece4-44a0-bf9b-a8bdb6a7e9ec","Convolutional Cross-View Pose Estimation","Xia, Z. (TU Delft Intelligent Vehicles); Booij, O. (TU Delft Pattern Recognition and Bioinformatics); Kooij, J.F.P. (TU Delft Intelligent Vehicles)","","2024","We propose a novel end-to-end method for cross-view pose estimation. Given a ground-level query image and an aerial image that covers the query's local neighborhood, the 3 Degrees-of-Freedom camera pose of the query is estimated by matching its image descriptor to descriptors of local regions within the aerial image. The orientation-aware descriptors are obtained by using a translationally equivariant convolutional ground image encoder and contrastive learning. The Localization Decoder produces a dense probability distribution in a coarse-to-fine manner with a novel Localization Matching Upsampling module. A smaller Orientation Decoder produces a vector field to condition the orientation estimate on the localization. Our method is validated on the VIGOR and KITTI datasets, where it surpasses the state-of-the-art baseline by 72% and 36% in median localization error for comparable orientation estimation accuracy. The predicted probability distribution can represent localization ambiguity, and enables rejecting possible erroneous predictions. Without re-training, the model can infer on ground images with different field of views and utilize orientation priors if available. On the Oxford RobotCar dataset, our method can reliably estimate the ego-vehicle's pose over time, achieving a median localization error under 1 meter and a median orientation error of around 1 degree at 14 FPS.","aerial imagery; camera pose estimation; Cameras; Cross-view matching; Decoding; Feature extraction; Image retrieval; localization; Location awareness; orientation estimation; Pose estimation; Task analysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-25","","","Intelligent Vehicles","","",""
"uuid:cdc1dfc4-04ad-424c-ab04-8da914ad27c0","http://resolver.tudelft.nl/uuid:cdc1dfc4-04ad-424c-ab04-8da914ad27c0","Occupancy Grid Mapping for Automotive Driving Exploiting Clustered Sparsity","Önen, Çağan (Student TU Delft; NXP Semiconductors); Pandharipande, Ashish (NXP Semiconductors); Joseph, G. (TU Delft Signal Processing Systems); Myers, N.J. (TU Delft Team Nitin Myers)","","2024","Occupancy grid maps provide information about obstacles and available free space in the environment and are crucial in automotive driving applications. An occupancy map is constructed using point cloud data from sensor modalities like LiDAR and radar used for automotive perception. In this paper, we formulate the problem of estimating the occupancy grid map using sensor point cloud data as a sparse binary occupancy value reconstruction problem. Our proposed occupancy grid estimation method, based on pattern-coupled sparse Bayesian learning, leverages the sparsity and spatial dependencies inherent in occupancy maps typically encountered in automotive scenarios. The proposed method shows enhanced detection capabilities compared to two benchmark methods, based on performance evaluation with scenes from the nuScenes and RADIal public datasets.","Sensor point clouds; LiDAR; Radar; nuScenes dataset; RADIal dataset; occupancy grids; pattern-coupled prior; spatial correlation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-19","","","Signal Processing Systems","","",""
"uuid:613ebcd3-48e7-4b09-a124-ebe324869ad5","http://resolver.tudelft.nl/uuid:613ebcd3-48e7-4b09-a124-ebe324869ad5","Toxic Online Environments are what Makes Rational Persuasion Become Wrongful","Marin, L. (TU Delft Ethics & Philosophy of Technology)","","2024","Suppose you wanted to switch to a healthier diet and searched for ideas online. You will unavoidably find some posts and videos where various influencers weigh in on this topic on social media platforms. Going down the rabbit hole of online searches, you see that the most vocal debate occurrs between two camps: the high fat versus the high carbohydrates. In these debates, a key argument is what counts as a blood marker for health assessment. Some say it is the LDL cholesterol, while others say that it is the triglycerides/HDL ratio. You are no medical expert (otherwise, you would not be searching for this online), so both technical debates are equally unfamiliar to you. Both sides can cite scientific studies showing that LDL and triglycerides/HDL are important health markers and that one is more relevant. If you were to side with any of the two camps, you would make a rational choice, given that both sides have factual and scientific arguments to support their claims. But depending on which side you are persuaded by, your diet will change radically, which will have long-term effects and possibly disastrous consequences for your health.
In deciding which side you take, the scale is not tipped by the strength of the reasons—since you cannot decide that—but on minor circumstances such as which side gets to present their reasons to you first. If it changes your attitude towards a healthy diet, this presentation of reasons will count as rational persuasion, following the schema provided by Mitchell and Douglas (2024).","Social Media; Persuasion; Manipulation; ethics of influence","en","journal article","","","","","","","","2024-09-24","","","Ethics & Philosophy of Technology","","",""
"uuid:be19ab33-cd0a-4a7c-89f9-494f1571d08d","http://resolver.tudelft.nl/uuid:be19ab33-cd0a-4a7c-89f9-494f1571d08d","When the Bear Comes to Town: How the City Could Create Nature","Roggema, Rob (Tecnologico de Monterrey); Rodriguez, Diego (Tecnologico de Monterrey); Tillie, Nico (TU Delft Landscape Architecture)","","2024","The relationship between humans and nature is in permanent change. Where the city and nature used to be seen as enemies that needed to be kept away from each other, the current paradigm looks at a more symbiotic relationship. In this, man is seen as part of nature, and the city is seen as a determining factor in providing conditions for a rich urban ecology. In this study, urban conditions are seen as the starting point for urban design, enabling biodiversity to thrive. The aim of the research is to distill design strategies that enhance nature in an urban context. These strategies are derived from existing theories, the typical relationship between the city and nature, and the understanding of the natural landscape, and are applied in the heated, dry, and rocky conditions in the metropolitan region of Monterrey, Mexico. The main finding is that the city contains ecologies with their own characteristics, often distinct from rural or natural ecologies. These specific conditions can be amplified using adequate design strategies, which may lead to a greater biodiversity. For improving urban biodiversity, the perspective on the city shall be transformed from seeing it as an enemy of nature towards a symbiotic relationship between the two. At the same time, this perspective requires additional research into two main aspects: the way the city is able to create its own climatic conditions, and how landscape-based design can enhance the urban conditions in a way nature occupies these novel ecological niches.","urban ecology; nature-based solutions; human-nature relationship; Monterrey; urban design; symbiocene","en","journal article","","","","","","","","","","","Landscape Architecture","","",""
"uuid:beb152e0-ae4f-4e7c-84ba-5919fb00a51a","http://resolver.tudelft.nl/uuid:beb152e0-ae4f-4e7c-84ba-5919fb00a51a","Instability in strongly stratified plane Couette flow with application to supercritical fluids","Bugeat, B. (TU Delft Energy Technology); Boldini, P.C. (TU Delft Energy Technology); Hasan, A.M. (TU Delft Energy Technology); Pecnik, Rene (TU Delft Energy Technology)","","2024","This paper addresses the stability of plane Couette flow in the presence of strong density and viscosity stratifications. It demonstrates the existence of a generalised inflection point that satisfies the generalised Fjørtoft criterion of instability when a minimum of kinematic viscosity is present in the base flow. The characteristic scales associated with this minimum are identified as the primary controlling parameters of the associated instability, regardless of the type of stratification. To support this finding, analytical stability models are derived in the long-wave approximation using piecewise linear base flows. Numerical stability calculations are carried out to validate these models and to provide further information on the production of disturbance vorticity. All instabilities are interpreted as arising from the interaction between two vorticity waves. Depending on the type of stratification, these two waves are produced by different physical mechanisms. When both strong density and viscosity stratifications are present, we show that they result from the concurrent action of shear and inertial baroclinic effects. The stability models developed for simple fluid models ultimately shed light on a recently observed unstable mode in supercritical fluids (Ren et al., J. Fluid Mech., vol. 871, 2019, pp. 831–864), providing a quantitative prediction of the stability diagram and identifying the dominant mechanisms at play. Furthermore, our study suggests that the minimum of kinematic viscosity reached at the Widom line in these fluids is the leading cause of their instability. The existence of similar instabilities in different fluids and flows (e.g. miscible fluids) is finally discussed.","stratified flows; shear-flow instability","en","journal article","","","","","","","","","","","Energy Technology","","",""
"uuid:9d702a9a-2857-49ce-b8c3-de7feb163461","http://resolver.tudelft.nl/uuid:9d702a9a-2857-49ce-b8c3-de7feb163461","Overcoming barriers to circularity for internal ICT management in organizations: A change management approach","McMahon, K.S. (TU Delft Responsible Marketing and Consumer Behavior); Mugge, R. (TU Delft Responsible Marketing and Consumer Behavior); Hultink, H.J. (TU Delft Responsible Marketing and Consumer Behavior)","","2024","Circularity-conscious management of information and communications technology (ICT) owned by organizations is important to achieving a circular economy. However, changes in organizational management toward circularity has been met with multiple challenges. This study uses 11 semi-structured interviews with on-the-ground ICT decision-makers in organizations to determine what barriers prevent the development and implementation of circularity-related changes in organizational ICT management. We identified 13 barriers relating to information and knowledge transfer, access to circular equipment, finances and contracts, and prioritization over circularity. Barrier-based interventions were further structured by Lewin's 3-step change management model – unfreeze, change, refreeze – highlighting the role of information access, relationships with contracted partners, and internal accountability and priority structures. These results bridge a currently underdeveloped link between circularity and management research as well as provide policy makers, researchers, and ICT managers insight on facilitating ICT's impactful role in society's transition to circularity.","Information and communications technology\; (ICT); Lifetime extension; circularity; Change management; Organizational change","en","journal article","","","","","","","","","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:470eeab4-a6d5-4f90-96df-d09aa33d793f","http://resolver.tudelft.nl/uuid:470eeab4-a6d5-4f90-96df-d09aa33d793f","A collaborative hybridity design approach: Enhancing urban water resilience and spatial legibility","Sugano, Keisuke (University of Tsukuba); Lu, Simo (Royal HaskoningDHV); Hooimeijer, F.L. (TU Delft Environmental Technology and Design); van de Ven, F.H.M. (Deltares)","","2024","Within the global transition to sustainable urban water management, Dutch polder cities are also contemplating revitalising their water traditions. One of the keys to this task is to integrate water management into urban design, which is explored but not yet practically instrumentalized in the urban design process. This article introduces the concept of hybridity and develops a Hybridity Design Approach as an interdisciplinary methodology to explore the possibility of realising the extreme low impact Closed City Concept. Integration of the water environment and urban space needs interdisciplinary cooperation and sharing knowledge, as well as an innovative way of thinking about water-resilient urban design, maximising the landscape quality of a polder city while minimising its hydrological footprint in the region. Effective visualisation tools and techniques for this collaborative design process are developed and tested in the area of Zevenkamp in Rotterdam.","hybridity design; urban water management; interdisciplinary design; visualisation; spatial quality","en","journal article","","","","","","","","","","","Environmental Technology and Design","","",""
"uuid:3dd51a82-aa13-4f51-875f-c96dd73b701d","http://resolver.tudelft.nl/uuid:3dd51a82-aa13-4f51-875f-c96dd73b701d","Mandating indoor air quality for public buildings: If some countries lead by example, standards may increasingly become normalized","Morawska, Lidia (Queensland University of Technology; University of Surrey); Allen, Joseph (Harvard T.H. Chan School of Public Health); Bahnfleth, William (The Pennsylvania State University); Bennett, Belinda (Queensland University of Technology); Bluyssen, P.M. (TU Delft Environmental & Climate Design); Boerstra, A.C. (TU Delft Environmental & Climate Design); Buonanno, Giorgio (University of Cassino and Southern Lazio); Cao, Junji (Chinese Academy of Sciences); Dancer, Stephanie J. (Edinburgh Napier University; NHS Lanarkshire)","","2024","People living in urban and industrialized societies, which are expanding globally, spend more than 90% of their time in the indoor environment, breathing indoor air (IA). Despite decades of research and advocacy, most countries do not have legislated indoor air quality (IAQ) performance standards for public spaces that address concentration levels of IA pollutants (1). Few building codes address operation, maintenance, and retrofitting, and most do not focus on airborne disease transmission. But the COVID-19 pandemic has made all levels of society, from community members to decision-makers, realize the importance of IAQ for human health, wellbeing, productivity, and learning. We propose that IAQ standards be mandatory for public spaces. Although enforcement of IAQ performance standards in homes is not possible, homes must be designed and equipped so that they could meet the standards.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-28","","","Environmental & Climate Design","","",""
"uuid:4754ccf9-0530-4d00-8e8c-93a6d9eb346f","http://resolver.tudelft.nl/uuid:4754ccf9-0530-4d00-8e8c-93a6d9eb346f","Advancing railway track health monitoring: Integrating GPR, InSAR and machine learning for enhanced asset management","Koohmishi, Mehdi (University of Bojnord, Iran); Kaewunruen, Sakdirat (University of Birmingham); Chang, L. (University of Twente); Guo, Y. (TU Delft Railway Engineering)","","2024","Railway track health monitoring and maintenance are crucial stages in railway asset management, aiming to enhance the train operation quality and service life. For this aim, various inspection means (using diverse non-destructive testing techniques) have been applied, however, these means are mostly not able to monitor whole railway track network or track underlying layers (e.g., ballast and subgrade). The use of remote sensing techniques, such as Interferometric Synthetic Aperture Radar (InSAR), can expedite the defect diagnosis process for railway tracks, elevating the scope of health monitoring to a network-wide level. The Ground Penetrating Radar (GPR) has emerged as a particularly reliable method, especially for detecting structural deficiencies in underlying layers. As a result, combining the two distinct non-destructive testing techniques – GPR and InSAR – presents a promising strategy for efficient railway asset management. Recognizing the significance of embracing newer and more advanced monitoring strategies, this paper reviews the fusion of GPR and InSAR methodologies, and explores the potential integration of machine learning models to develop a predictive health monitoring and condition-based maintenance approach for railway tracks.","Condition-based railway maintenance; GPR; Ground-penetrating radar; InSAR; Inspection; Machine learning; Non-destructive testing; Railway ballasted track; SAR interferometry","en","review","","","","","","","","","","","Railway Engineering","","",""
"uuid:9ae83340-1407-405d-918d-37402de72b7f","http://resolver.tudelft.nl/uuid:9ae83340-1407-405d-918d-37402de72b7f","Designing for usability: development and evaluation of a portable minimally-actuated haptic hand and forearm trainer for unsupervised stroke rehabilitation","Rätz, R. (TU Delft Human-Robot Interaction; University of Bern); Ratschat, A.L. (TU Delft Human-Robot Interaction; Erasmus MC); Cividanes Garcia, N. (TU Delft Cognitive Robotics); Ribbers, G.M. (Erasmus MC; Rijndam Rehabilitation Center); Marchal Crespo, L. (TU Delft Human-Robot Interaction; University of Bern; Erasmus MC)","","2024","In stroke rehabilitation, simple robotic devices hold the potential to increase the training dosage in group therapies and to enable continued therapy at home after hospital discharge. However, we identified a lack of portable and cost-effective devices that not only focus on improving motor functions but also address sensory deficits. Thus, we designed a minimally-actuated hand training device that incorporates active grasping movements and passive pronosupination, complemented by a rehabilitative game with meaningful haptic feedback. Following a human-centered design approach, we conducted a usability study with 13 healthy participants, including three therapists. In a simulated unsupervised environment, the naive participants had to set up and use the device based on written instructions. Our mixed-methods approach included quantitative data from performance metrics, standardized questionnaires, and eye tracking, alongside qualitative feedback from semi-structured interviews. The study results highlighted the device's overall ease of setup and use, as well as its realistic haptic feedback. The eye-tracking analysis further suggested that participants felt safe during usage. Moreover, the study provided crucial insights for future improvements such as a more intuitive and comfortable wrist fixation, more natural pronosupination movements, and easier-to-follow instructions. Our research underscores the importance of continuous testing in the development process and offers significant contributions to the design of user-friendly, unsupervised neurorehabilitation technologies to improve sensorimotor stroke rehabilitation.","neurorehabilitation; robotic; home rehabilitation; group therapy; haptic rendering; portable; grasping; usability","en","journal article","","","","","","","","","","Cognitive Robotics","Human-Robot Interaction","","",""
"uuid:8df21568-80b8-417a-b700-1683fe2300a4","http://resolver.tudelft.nl/uuid:8df21568-80b8-417a-b700-1683fe2300a4","Hydrodynamic Characterization of Carbonate Aquifers Using Atypical Pumping Tests without the Interruption of the Drinking Water Supply","Rusi, Sergio (University G. D'Annunzio of Chieti-Pescara); Di Curzio, Diego (TU Delft Sanitary Engineering); Di Giovanni, Alessia (University G. D'Annunzio of Chieti-Pescara)","","2024","The Gran Sasso carbonate aquifer is the largest and most productive in the Apennines. Its hydrogeological structure has been studied since the middle of the last century for the springs’ characterization for drinking purposes and for a motorway tunnel. Meanwhile, its hydrodynamic parametrization is less developed and has been limited to monitoring the discharge and chemical and isotopic parameters. Secondary porosity characterizes the aquifer, and an underlying impermeable marly complex represents the basal aquiclude. It might appear inappropriate to characterize the hydraulic properties via pumping tests, as their reliability has been proven in homogeneous and isotropic media. However, the high extent of the aquifer, the wells’ location, the scarcity of information available and the lack of alternatives has forced the estimation of hydrodynamic parameters as in porous aquifers and the experimental testing of the aquifer, especially in maximum pumping conditions, for a possible exploitation increase. Since aquifer testing was performed during the normal well field’s activities, it was not possible to perform typical tests. Therefore, the step-drawdown test was conducted by turning on an increasing number of wells over time and keeping the observation points fixed. As results, a mean hydraulic conductivity of 5 × 10−3 m/s and a mean transmissivity of 0.3 m2/s were established without interrupting the water supply; meanwhile, the influence radius and flow directions were also estimated.","pumping test; carbonate aquifer; hydrodynamic characterization","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:d9a7383d-ac87-436d-a44b-348070a4806c","http://resolver.tudelft.nl/uuid:d9a7383d-ac87-436d-a44b-348070a4806c","Challenges and opportunities for CO2 electroreduction from a process systems engineering perspective","Dal Mas, R. (TU Delft ChemE/Process Systems Engineering); Somoza Tornos, A. (TU Delft ChemE/Process Systems Engineering); Pérez-Fortes, Mar (TU Delft Energie and Industrie); Kortlever, R. (TU Delft Large Scale Energy Storage); Kiss, A.A. (TU Delft ChemE/Process Systems Engineering)","","2024","Despite the huge efforts devoted to the development of the electrochemical reduction of CO2 (ECO2R) in the past decade, still many challenges are present, hindering further approaches to industrial applications. This paper gives a perspective on these challenges from a Process Systems Engineering (PSE) standpoint, while at the same time highlighting the opportunities for advancements in the field in the European context. The challenges are connected with: the coupling of these processes with renewable electricity generation; the feedstock (in particular CO2); the processes itself; and the different products that can be obtained. PSE can determine the optimal interactions among the components of such systems, allowing educated decision making in designing the best process configurations under uncertainty and constrains. The opportunities, on the other hand, stem from a stronger collaboration between the PSE and the experimental communities, from the possibility of integrating ECO2R into existing industrial productions and from process-wide optimisation studies, encompassing the whole production cycle of the chemicals to exploit possible synergies.","CO2 electroreduction; CO2 utilisation; green processing; electrification; process systems engineering","en","journal article","","","","","","","","","","","ChemE/Process Systems Engineering","","",""
"uuid:828f3643-6245-4346-bde6-5afae21c479a","http://resolver.tudelft.nl/uuid:828f3643-6245-4346-bde6-5afae21c479a","Practical potential of suspension electrodes for enhanced limiting currents in electrochemical CO2 reduction†","Ligthart, N.E.G. (TU Delft ChemE/Transport Phenomena); Prats Vergel, G. (TU Delft ChemE/Materials for Energy Conversion and Storage); Padding, J.T. (TU Delft Complex Fluid Processing); Vermaas, D.A. (TU Delft ChemE/Transport Phenomena)","","2024","CO2 conversion is an important part of the transition towards clean fuels and chemicals. However, low solubility of CO2 in water and its slow diffusion cause mass transfer limitations in aqueous electrochemical CO2 reduction. This significantly limits the partial current densities towards any desired CO2-reduction product. We propose using flowable suspension electrodes to spread the current over a larger volume and alleviate mass transfer limitations, which could allow high partial current densities for CO2 conversion even in aqueous environments. To identify the requirements for a well-performing suspension electrode, we use a transmission line model to simulate the local electric and ionic current distributions throughout a channel and show that the electrocatalysis is best distributed over the catholyte volume when the electric, ionic and charge transfer resistances are balanced. In addition, we used electrochemical impedance spectroscopy to measure the different resistance contributions and correlated the results with rheology measurements to show that particle size and shape impact the ever-present trade-off between conductivity and flowability. We combine the modelling and experimental results to evaluate which carbon type is most suitable for use in a suspension electrode for CO2 reduction, and predict a good reaction distribution throughout activated carbon and carbon black suspensions. Finally, we tested several suspension electrodes in a CO2 electrolyzer. Even though mass transport limitations should be reduced, the CO partial current densities are capped at 2.8 mA cm−2, which may be due to engineering limitations. We conclude that using suspension electrodes is challenging for sensitive reactions like CO2 reduction, and may be more suitable for use in other electrochemical conversion reactions suffering from mass transfer limitations that are less affected by competing reactions and contaminations.","","en","journal article","","","","","","","","","","","ChemE/Transport Phenomena","","",""
"uuid:aca9114b-2641-4c21-be19-3f7ad782cfcb","http://resolver.tudelft.nl/uuid:aca9114b-2641-4c21-be19-3f7ad782cfcb","Sensitivity analysis of inverted model parameters from transient electromagnetic measurements affected by induced polarization effects","Aigner, Lukas (Technische Universität Wien); Werthmüller, D. (TU Delft Applied Geophysics and Petrophysics); Flores Orozco, Adrián (Technische Universität Wien)","","2024","We investigate the application of the distance-based global sensitivity analysis (DGSA) to evaluate the sensitivity of electrical model parameters obtained from transient electromagnetic (TEM) data including induced polarization (IP) effects. We propose novel open-source forward modeling and inversion routines for single-loop TEM data including IP effects with the maximum phase angle model to model the frequency dependence of the complex resistivity. In a first step, we evaluate the accuracy of our forward modeling and inversion routines using numerical studies, where the actual variations of layer thicknesses and resistivities, as well as the frequency dependence of the complex resistivity is known. In a second step, we extend our investigation to field data and apply our approach to three distinct case studies in layered media: 1) a confined aquifer corresponding to conductive non-polarizable media, 2) a graphite deposit corresponding to highly conductive and polarizable anomalies in a resistive host rock and 3) an ice glacier corresponding to highly resistive polarizable media. Our DGSA results reveal that standard depth of investigation (DOI) approaches may overestimate the true sensitivity of the model obtained from the inversion. TEM data collected in conductive layered media without IP effects show reduced sensitivity above the predicted DOI. The case studies in polarizable media demonstrate that the maximum phase angle is more influential on the TEM model response than the relaxation time and dispersion coefficient. Our DGSA results for polarizable media reveal that TEM field data collected at the graphite deposit and at the ice glacier are sensitive to the geometry of the polarizable layer.","Distance-based global sensitivity analysis; Forward modeling and inversion of transient electromagnetic method; Frozen ground and graphite ores; Induced polarization effect","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-08","","","Applied Geophysics and Petrophysics","","",""
"uuid:066d0baa-c979-4622-891e-05497cb006e4","http://resolver.tudelft.nl/uuid:066d0baa-c979-4622-891e-05497cb006e4","The Sequence Matters in Learning - A Systematic Literature Review","Valle Torre, M. (TU Delft Web Information Systems); Oertel, Catharine (TU Delft Interactive Intelligence); Specht, M.M. (TU Delft Web Information Systems)","","2024","Describing and analysing learner behaviour using sequential data and analysis is becoming more and more popular in Learning Analytics. Nevertheless, we found a variety of definitions of learning sequences, as well as choices regarding data aggregation and the methods implemented for analysis. Furthermore, sequences are used to study different educational settings and serve as a base for various interventions. In this literature review, the authors aim to generate an overview of these aspects to describe the current state of using sequence analysis in educational support and learning analytics. The 74 included articles were selected based on the criteria that they conduct empirical research on an educational environment using sequences of learning actions as the main focus of their analysis. The results enable us to highlight different learning tasks where sequences are analysed, identify data mapping strategies for different types of sequence actions, differentiate techniques based on purpose and scope, and identify educational interventions based on the outcomes of sequence analysis.","","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Web Information Systems","","",""
"uuid:4e00b222-29ce-4789-a2b3-881d876294c8","http://resolver.tudelft.nl/uuid:4e00b222-29ce-4789-a2b3-881d876294c8","Physical science research needed to evaluate the viability and risks of marine cloud brightening","Feingold, Graham (National Oceanic and Atmospheric Administration); Ghate, Virendra P. (Argonne National Laboratory); Russell, Lynn M. (University of California); Blossey, Peter (University of Washington); Cantrell, Will (Michigan Technological University); Christensen, Matthew W. (Pacific Northwest National Laboratory); Diamond, Michael S. (Florida State University); Gettelman, Andrew (Pacific Northwest National Laboratory); Glassmeier, F. (TU Delft Atmospheric Remote Sensing)","","2024","Marine cloud brightening (MCB) is the deliberate injection of aerosol particles into shallow marine clouds to increase their reflection of solar radiation and reduce the amount of energy absorbed by the climate system. From the physical science perspective, the consensus of a broad international group of scientists is that the viability of MCB will ultimately depend on whether observations and models can robustly assess the scale-up of local-to-global brightening in today's climate and identify strategies that will ensure an equitable geographical distribution of the benefits and risks associated with projected regional changes in temperature and precipitation. To address the physical science knowledge gaps required to assess the societal implications of MCB, we propose a substantial and targeted program of research-field and laboratory experiments, monitoring, and numerical modeling across a range of scales.","","en","review","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:b5a1797d-d52e-4267-93b2-b6f39a61ae1a","http://resolver.tudelft.nl/uuid:b5a1797d-d52e-4267-93b2-b6f39a61ae1a","Flow patterns in ascending aortic aneurysms: Determining the role of hypertension using phase contrast magnetic resonance and computational fluid dynamics","Ramaekers, M. J.F.G. (Maastricht UMC); van der Vlugt, I.B. (TU Delft ChemE/Transport Phenomena); Westenberg, J. J.M. (Leiden University Medical Center); Perinajová, R. (TU Delft ChemE/Transport Phenomena; TU Delft J.M. Burgers Center for Fluid Mechanics); Lamb, H. J. (Leiden University Medical Center); Wildberger, J. E. (Maastricht UMC); Kenjeres, S. (TU Delft ChemE/Transport Phenomena); Schalla, S. (Maastricht UMC)","","2024","Thoracic aortic aneurysm (TAA) is a local dilation of the thoracic aorta. Although universally used, aneurysm diameter alone is a poor predictor of major complications such as rupture. There is a need for better biomarkers for risk assessment that also reflect the aberrant flow patterns found in TAAs. Furthermore, hypertension is often present in TAA patients and may play a role in progression of aneurysm. The exact relation between TAAs and hypertension is poorly understood. This study aims to create a numerical model of hypertension in the aorta by using computational fluid dynamics. First, a normotensive state was simulated in which flow and resistance were kept unaltered. Second, a hypertensive state was modeled in which blood inflow was increased by 30%. Third, a hypertensive state was modeled in which the proximal and peripheral resistances and capacitance parameters from the three-element Windkessel boundary condition were adjusted to mimic an increase in resistance of the rest of the cardiovascular system. One patient with degenerative TAA and one healthy control were successfully simulated at hypertensive states and were extensively analyzed. Furthermore, three additional TAA patients and controls were simulated to validate our method. Hemodynamic variables such as wall shear stress, oscillatory shear index, endothelial cell activation potential (ECAP), vorticity and helicity were studied to gain more insight on the effects of hypertension on flow patterns in TAAs. By comparing a TAA patient and a control at normotensive state at peak-systole, helicity and vorticity were found to be lower in the TAA patient throughout the entire domain. No major changes in flow and flow derived quantities were observed for the TAA patient and control when resistance was increased. When flow rate was increased, regions with high ECAP values were found to reduce in TAA patients in the aneurysm region which could reduce the risk of thrombogenesis. Thus, it may be important to assess cardiac output in patients with TAA.","4D flow MRI; Aortic aneurysm; Blood flow; CFD; Hypertension","en","journal article","","","","","","","","","","","ChemE/Transport Phenomena","","",""
"uuid:9f0ada21-aa65-4917-b2fe-6fa17c1830c7","http://resolver.tudelft.nl/uuid:9f0ada21-aa65-4917-b2fe-6fa17c1830c7","Vector-flow imaging of slowly moving ex vivo blood with photoacoustics and pulse-echo ultrasound","Smith, Caitlin (The University of Auckland); Shepherd, Jami (The University of Auckland); Renaud, G.G.J. (TU Delft ImPhys/Verweij group); van Wijk, Kasper (The University of Auckland)","","2024","We present a technique called photoacoustic vector-flow (PAVF) to quantify the speed and direction of flowing optical absorbers at each pixel from acoustic-resolution PA images. By varying the receiving angle at each pixel in post-processing, we obtain multiple estimates of the phase difference between consecutive frames. These are used to solve the overdetermined photoacoustic Doppler equation with a least-squares approach to estimate a velocity vector at each pixel. This technique is tested in bench-top experiments and compared to simultaneous pulse-echo ultrasound vector-flow (USVF) on whole rat blood at speeds on the order of 1 mm/s. Unlike USVF, PAVF can detect flow without stationary clutter filtering in this experiment, although the velocity estimates are highly underestimated. When applying spatio-temporal singular value decomposition clutter filtering, the flow speed can be accurately estimated with an error of 16.8% for USVF and −8.9% for PAVF for an average flow speed of 2.5 mm/s.","Blood flow; Flowmetry; Hemodynamics; Perfusion; Photoacoustic vector-flow; Ultrasound vector-flow; Vector-flow imaging; Velocimetry","en","journal article","","","","","","","","","","","ImPhys/Verweij group","","",""
"uuid:a9efadf7-d88e-4981-860d-cd39d1c6d7b8","http://resolver.tudelft.nl/uuid:a9efadf7-d88e-4981-860d-cd39d1c6d7b8","Electrochemical CO2 reduction on a copper foam electrode at elevated pressures","Girichandran, N. (TU Delft Large Scale Energy Storage); Saedy, S. (TU Delft ChemE/Product and Process Engineering); Kortlever, R. (TU Delft Large Scale Energy Storage)","","2024","Electrochemical CO2 reduction is a promising way of closing the carbon cycle while synthesizing useful commodity chemicals and fuels. One of the possible routes to scale up the process is CO2 reduction at elevated pressure, as this is a way to increase the concentration of poorly soluble CO2 in aqueous systems. Yet, not many studies focus on this route, owing to the inherent challenges with high-pressure systems, such as leaks, product quantification, and ease of operation. In this study, we use a high-pressure flow cell setup to investigate the impact of CO2 pressure on the electrochemical performance of a copper foam electrode for CO2 reduction within a pressure range of 1 to 25 bar. Our initial findings using a 0.5 M potassium bicarbonate (KHCO3) electrolyte show a consistent improvement in selectivity towards CO2 reduction products, with HCOOH being the dominant product. By conducting a systematic exploration of operating parameters including applied current density, applied CO2 pressure, cation effect, and electrolyte concentration, the selectivity towards formate (HCOOH) is optimized, achieving a remarkable 70 % faradaic efficiency (FE) under moderate conditions of 25 bar in a 0.5 M cesium bicarbonate (CsHCO3) electrolyte. Additionally, we report the synthesis of isopropanol with a FE of 11 % at the 25 bar in 0.5 M KHCO3 which is the highest reported selectivity towards isopropanol on copper using a bicarbonate system.","","en","journal article","","","","","","","","","","","Large Scale Energy Storage","","",""
"uuid:798cacc3-f212-4216-9098-08658de273d5","http://resolver.tudelft.nl/uuid:798cacc3-f212-4216-9098-08658de273d5","Artificial Biocatalysis: Quo Vadis?","Ingram, A.A. (TU Delft BT/Biocatalysis); Oike, K. (TU Delft BT/Biocatalysis)","","2024","Astonishing progress has been achieved in unlocking new-to-nature biocatalysis in the past decades. The progress in protein engineering enabled research to efficiently incorporate artificial structural elements into enzyme design. Recent trends include cofactor mimetics, artificial metalloenzymes and non-canonical amino acids. In this perspective article, we present the state-of-the-art, discuss recent examples and our view on what we call artificial biocatalysis. Although these artificial systems undoubtedly increase the scope of biocatalysis, their applicability remains challenging. Fundamental questions regarding the impact of this research field are addressed in this perspective.","Artificial metalloenzymes; Biocatalysis; Directed evolution; non-canonical amino acids; Protein engineering","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:46f5f85d-d877-4a66-a67c-a470e142cd41","http://resolver.tudelft.nl/uuid:46f5f85d-d877-4a66-a67c-a470e142cd41","Fabrication of low thermal expansion Fe–Ni alloys by in-situ alloying using twin-wire arc additive manufacturing","Sood, A. (TU Delft Team Marcel Hermans); Schimmel, Jim (Student TU Delft); Bosman, Marko (Fokker/GKN Aerospace); Goulas, Constantinos (University of Twente); Popovich, V. (TU Delft Team Vera Popovich); Hermans, M.J.M. (TU Delft Team Marcel Hermans)","","2024","The binary Fe–Ni system offers alloys with notably low linear coefficients of thermal expansion (CTE), contingent upon their Ni content. In this respect twin-wire arc additive manufacturing (T-WAAM) presents the opportunity of in-situ alloying through the simultaneous feeding of two metal wires into a weld pool to obtain desired alloy compositions. This study aims to deposit a graded wall with Ni contents targeted at 42, 46, and 52 wt% in the building direction of the wall, along with a block comprising of 46 wt% Ni, employing the T-WAAM approach. The results show effective incorporation of additional Ni into the weld pool and geometrically stable weld beads in the continuous metal transfer mode during the T-WAAM process. This mode led to the defect-free and chemically stable deposition of the graded wall and the block with average Ni contents of 42.3 ± 1.1, 45.8 ± 1.4, 52.6 ± 0.8 wt%, and 46.4 ± 0.9 wt%, respectively. The measured Curie temperatures of the as-deposited alloys and the mean CTE values of alloy 46 were found to be comparable to the commercial alloys. In summary, this study validates the feasibility of in-situ deposition of low thermal expansion alloy compositions, thereby enabling the possibility of on-demand thermal expansion properties.","Fe-Ni alloys; Functional grading; In-situ alloying; T-WAAM; Thermal expansion","en","journal article","","","","","","","","","","","Team Marcel Hermans","","",""
"uuid:c4357027-4d2e-4403-8a93-f2413a832f3f","http://resolver.tudelft.nl/uuid:c4357027-4d2e-4403-8a93-f2413a832f3f","A synthetic agent to simulate decisional behaviour of designers working with an active recommender framework system","Horvath, I. (TU Delft Industrial Design Engineering; TU Delft Cyber-Physical Systems); Tepjit, Sirasak (King Mongkut’s University of Technology North Bangkok, Bangkok)","","2024","Application-specific reasoning mechanisms (ASRMs) development is a rapidly growing domain of systems engineering. A demonstrative implementation of an active recommender system (ARS) was realized to support designing ASRMs and to circumvent procedural obstacles by providing context-sensitive recommendations. The specific problem for the research presented in this paper was the development of a synthetic validation agent (SVA) to simulate the decisional behaviour of designers and to generate data about the usefulness of the recommendations. The fact of the matter is that the need for the SVA was raised by the pandemic, which prevented involving groups of human designers in the recommendation testing process. The reported research had three practical goals: (i) development of the logical fundamentals for the SVA, (ii) computational implementation of the SVA, and (iii) application of the SVA in data generation for the evaluation of usefulness of recommendation. The SVA is based on a probabilistic decisional model that quantifies decisional options according to the assumed decisional tendencies. The three key concepts underlying the SVA are (i) decisional logic, (ii) decisional knowledge, and (iii) decisional probability. These together enable generation of reliable data about the decisional behaviours of human designers concerning the obtained recommendations. The completed tests proved the above assumption.","decisional behaviour; decisional modes; decisional variables; shared design knowledge; Synthetic validation agent; usefulness of recommendation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-19","Industrial Design Engineering","","Cyber-Physical Systems","","",""
"uuid:c0172f2c-3de1-42e0-91f6-b1f001ec599f","http://resolver.tudelft.nl/uuid:c0172f2c-3de1-42e0-91f6-b1f001ec599f","Utilization of synthetic system intelligence as a new industrial asset","Horvath, I. (TU Delft Cyber-Physical Systems)","","2024","System knowledge and reasoning mechanisms are essential means for intellectualization of cyber-physical systems (CPSs). As enablers of system intelligence, they make such systems able to solve application problems and to maintain their efficient operation. Normally, system intelligence has a human-created initial part and a system-produced (extending) part, called synthetic system intelligence (SSI). This position paper claims that SSI can be converted to a new industrial asset and utilized as such. Unfortunately, no overall theory of SSI exists and its conceptual framework, management strategy, and computational methodologies are still in a premature stage. This is the main reason why no significant progress has been achieved in this field, contrary to the latent potentials. This paper intends to contribute to: (i) understanding the nature and fundamentals of SSI, (ii) systematizing the elicitation and transfer of SSI, (iii) exploration of analogical approaches to utilization of SSI, and (iv) road-mapping and scenario development for the exploitation of SSI as an industrial asset. First, the state of the art is surveyed and the major findings are presented. Then, four families of analogical approaches to SSI transfer are analyzed. These are: (i) knowledge transfer based on repositories, (ii) transfer among agents, (iii) transfer of learning resources, and (iv) transfer by emerging approaches. A procedural framework is proposed that identifies the generic functionalities needed for a quasi-autonomous handling of SSI as an industrial asset. The last section casts light on some important open issues and necessary follow-up research and development activities.","asset exploitation; computational reasoning mechanisms; Intellectualized systems; practice of transfer; problem solving knowledge; synthetic system intelligence","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-19","","","Cyber-Physical Systems","","",""
"uuid:dff4191e-34f3-481e-a0b0-e7188975dc6d","http://resolver.tudelft.nl/uuid:dff4191e-34f3-481e-a0b0-e7188975dc6d","Crashworthiness analysis of empty and foam-filled circular tubes with functionally graded thickness","Barzigar, Seyed Sajad (Tarbiat Modares University); Ahmadi, Hamed (Tarbiat Modares University); Liaghat, Gholamhossein (Tarbiat Modares University; Oxford Brookes University); Seidi, Morteza (University of Texas at San Antonio); Mirzaali, Mohammad J. (TU Delft Biomaterials & Tissue Biomechanics)","","2024","Thin-wall structures, particularly thin-walled tubes, play a critical role in load-bearing structures. Enhancing their ability to withstand crushing loads can significantly improve the overall damping efficiency of the system. Functionally graded thickness (FGT) is a promising approach for enhancing the load-bearing properties of thin-walled tubes by enabling control over material usage and localized deformation patterns within the structure. In this study, we proposed a novel theoretical model that analyzes the crushing behavior of hollow and foam-filled FGT thin-walled circular tubes by considering four primary failure mechanisms that contribute to energy dissipation: (1) bending of plastic hinges, (2) membrane stretching, (3) axial foam crushing, and (4) the interaction between foam and the tube's wall. We validated our model against experimental results from previous researchers and observed a good agreement. Additionally, we conduct a comprehensive study to examine the effects of various geometrical parameters, such as power-law functions and normalized wall thickness ratio, on the crushing behavior of FGT structures. Our results demonstrate the accuracy and reliability of our theoretical model and highlight the potential of FGT structures to enhance the performance of thin-walled tubes in a range of load-bearing applications.","Circular tube; Foam-filled tube; Functionally graded thickness; Theoretical model; Thin-wall structures","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-12","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:c618625b-0193-42be-9edc-dc187a89eea3","http://resolver.tudelft.nl/uuid:c618625b-0193-42be-9edc-dc187a89eea3","Rapid single-shot parity spin readout in a silicon double quantum dot with fidelity exceeding 99%","Takeda, Kenta (RIKEN Center for Emergent Matter Science (CEMS)); Noiri, Akito (RIKEN Center for Emergent Matter Science (CEMS)); Nakajima, Takashi (RIKEN Center for Emergent Matter Science (CEMS)); Camenzind, Leon C. (RIKEN Center for Emergent Matter Science (CEMS)); Kobayashi, Takashi (RIKEN Center for Quantum Computing (RQC), Wako); Sammak, A. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; TNO); Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Tarucha, Seigo (RIKEN Center for Quantum Computing (RQC), Wako; RIKEN Center for Emergent Matter Science (CEMS))","","2024","Silicon-based spin qubits offer a potential pathway toward realizing a scalable quantum computer owing to their compatibility with semiconductor manufacturing technologies. Recent experiments in this system have demonstrated crucial technologies, including high-fidelity quantum gates and multiqubit operation. However, the realization of a fault-tolerant quantum computer requires a high-fidelity spin measurement faster than decoherence. To address this challenge, we characterize and optimize the initialization and measurement procedures using the parity-mode Pauli spin blockade technique. Here, we demonstrate a rapid (with a duration of a few μs) and accurate (with >99% fidelity) parity spin measurement in a silicon double quantum dot. These results represent a significant step forward toward implementing measurement-based quantum error correction in silicon.","","en","journal article","","","","","","","","","","","BUS/TNO STAFF","","",""
"uuid:fe78fc93-8eaf-463a-9bec-4e9fab858a01","http://resolver.tudelft.nl/uuid:fe78fc93-8eaf-463a-9bec-4e9fab858a01","Mapping the CityGML Energy ADE to CityGML 3.0 Using a Model-Driven Approach","Bachert, Carolin (con terra GmbH); León Sánchez, C.A. (TU Delft Urban Data Science); Kutzner, Tatjana (Technische Universitat Munchen (TUM)); Agugiaro, G. (TU Delft Urban Data Science)","","2024","With the increasing adoption of semantic 3D city models, the relevance of applications in the field of Urban Building Energy Modelling (UBEM) has rapidly grown, as the building sector accounts for a large part of the total energy consumption. UBEM allows us to better understand the energy performance of the building stock and can contribute to defining refurbishment strategies. However, UBEM applications require lots of heterogeneous data, eventually advocating for standards for data interoperability. The Energy Application Domain Extension has been created to cope with UBEM data requirements and offers a standardised data model that builds upon the CityGML standard. The Energy ADE 1.0, released in 2018, creates new classes and adds new properties to existing classes of the CityGML 2.0 Core and Building modules. CityGML 3.0, released in 2021, has introduced several changes to the data model and its ADE mechanism. These changes render the Energy ADE incompatible with CityGML 3.0. This article presents how the Energy ADE has been ported to CityGML 3.0 to allow, on the one hand, for a lossless data conversion and, on the other hand, to exploit the new characteristics of CityGML 3.0 while keeping a logical symmetry between the ADE classes of both CityGML versions. The article describes the chosen methodology, the mapping strategies, the implementation steps, as well as the data conversion tests to check the validity of the “new” Energy ADE for CityGML 3.0.","CityGML; Energy ADE; Model-driven mapping; Data modelling; UBEM","en","journal article","","","","","","","","","","","Urban Data Science","","",""
"uuid:d6dc875d-bba1-4a65-bd7c-f60d8362cfbd","http://resolver.tudelft.nl/uuid:d6dc875d-bba1-4a65-bd7c-f60d8362cfbd","Conclusion: Limitations and Future Research","Plugge, A.G. (TU Delft Responsible Marketing and Consumer Behavior); Nikou, S. (TU Delft Responsible Marketing and Consumer Behavior)","Plugge, Albert (editor); Nikou, Shahrokh (editor)","2024","In this book, we introduced four objectives to explore which antecedents form a part of an enterprise orchestration capability that aims at integrating internal and external resources. We theoretically developed and empirically validated a business services portfolio model and its corresponding antecedents. More specifically, we demonstrated how digitalisation may overcome business services implementation barriers. Overall, we focus on digitalised Global Business Services (GBSs) in the context of a plural sourcing strategy and provided evidence how an enterprise ecosystem approach may decrease GBS implementation challenges. In doing so, we operationalised our definition as described in the introduction “An enterprise ecosystem is a socio-technical environment in which individuals within organisational units, which are supported by digital interactions, collaborate in co-creating, implementing and orchestrating GBSs in order to create business value”.","","en","book chapter","Springer International Publishing","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-27","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:5a5665c4-596f-4a9b-9791-a589ae74d48a","http://resolver.tudelft.nl/uuid:5a5665c4-596f-4a9b-9791-a589ae74d48a","Subsidies or green taxes?: Evaluating the distributional effects of housing renovation policies among Dutch households","Fernández Pérez, A. (TU Delft Urban Development Management); Haffner, M.E.A. (TU Delft Urban Development Management); Elsinga, M.G. (TU Delft Urban Development Management)","","2024","Despite persistent housing affordability issues, energy policy and housing renovation are usually investigated separately from housing costs other than energy. Researchers have examined the financial viability of renovation attending to building conditions and the socio-economic characteristics of their occupants. However, the distributional impacts of renovation incentives and the potential of fiscal policy to redistribute housing costs remain understudied. Dutch fiscal policy, favouring homeownership, offers a relevant context to evaluate how property taxation can boost renovation rates. The novelty of this paper resides in investigating the impact of two policies, the current direct subsidy and a proposal for a green tax, on both the financial viability of renovation and the subsequent distribution of housing costs. The proposed green tax combines energy efficiency and taxation of property revenue. We employ a model considering marginal costs of housing renovation, obtained from a government dataset, and marginal benefits, drawn from a hedonic regression. We assess the distributional impacts of different policy scenarios by examining changes in user costs across income deciles. Our findings indicate that existing renovation subsidies exacerbate the regressive distributional impacts resulting from the current housing taxation system in the Netherlands. Introducing energy-efficiency-linked property taxation can make homeownership fiscality less regressive while incentivising housing renovation. Ultimately, this study highlights the importance of incorporating housing affordability as a fundamental element in renovation policies to balance environmental and distributional objectives.","Distributional impact; Green taxes; Housing renovation; Housing value; User costs","en","journal article","","","","","","","","","","","Urban Development Management","","",""
"uuid:453f9039-47f3-49b4-aa49-cdba5ba41459","http://resolver.tudelft.nl/uuid:453f9039-47f3-49b4-aa49-cdba5ba41459","Do laundry when the sun shines: Factors that promote loadshifting in Dutch households with solar panels","Hubert, Naomi D. (Student TU Delft); Biely, Katharina (Wageningen University & Research); Kamp, L.M. (TU Delft Energie and Industrie); de Vries, G. (TU Delft Organisation & Governance)","","2024","The installation of solar panels by residential households is vital for the energy transition. However, the rapid uptake of solar panels by households leads to congestion in the electricity grid. Specifically, when the sun shines, these solar panels simultaneously produce a lot of electricity that is fed into the grid, which is inefficient and can destabilize the grid. Consequently, it is better if self-produced solar energy is directly consumed when the sun is shining. Loadshifting involves shifting energy use (e.g., doing laundry) to periods in which energy is produced. This necessitates behavior change within the household, and it is not yet well understood why people struggle to loadshift. To assess the individualistic and contextual factors influencing laundry loadshifting behavior in the Netherlands, we conducted a survey among 283 Dutch households with solar panels. The survey builds on a framework that integrates aspects of the theory of planned behavior and social practice theory. The framework comprises eight factors (sufficiency attitude, user beliefs, know-how, monitoring skills, habits, hassle, practical knowledge provided, and feedback provision by system design), which are quantitatively measured and analyzed. We used multiple regression analysis to explore the collected responses. Results show the relevance of monitoring skills, strong habits, passive user beliefs and practical knowledge for laundry loadshifting behavior. Findings highlight that instead of asking people to adjust to technologies, technologies should support behavior change and understand its intricacies and connections to its broader context. Additionally, it is important to strengthen households' beliefs regarding their active role in the energy system.","Solar energy; Behavior change; Loadshifting; Sustainability; Energy transition","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:ad04f4bf-08d4-4c69-adb6-773b0de9d951","http://resolver.tudelft.nl/uuid:ad04f4bf-08d4-4c69-adb6-773b0de9d951","Quantitative Research","Plugge, A.G. (TU Delft Responsible Marketing and Consumer Behavior); Nikou, S. (TU Delft Responsible Marketing and Consumer Behavior)","Plugge, Albert (editor); Nikou, Shahrokh (editor)","2024","This chapter describes the quantitative research that we conducted to examine the path relationships depicted in the conceptual research model (see Fig. 3.1). We employed Partial Least Squares Structural Equation Modelling (PLS-SEM) technique (Hair et al., 2016) to test the hypotheses and the relationships between the antecedents of business services portfolio. This approach seems to be appropriate for the research at hand. Overall, PLS-SEM offers a flexible and robust approach to test relationships and hypotheses, particularly in situations where sample size is small, and the conceptual model (see Fig. 3.1) is complex, and the research is exploratory or prediction-oriented.","","en","book chapter","Springer International Publishing","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-27","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:a423075a-61a8-4e32-a6d8-6d1ec0e6a5ba","http://resolver.tudelft.nl/uuid:a423075a-61a8-4e32-a6d8-6d1ec0e6a5ba","Configurational Thinking Approach","Plugge, A.G. (TU Delft Responsible Marketing and Consumer Behavior); Nikou, S. (TU Delft Responsible Marketing and Consumer Behavior)","Plugge, Albert (editor); Nikou, Shahrokh (editor)","2024","In the present chapter, our investigative focus shifts towards a nuanced exploration of the determinants shaping the orchestration of a business service portfolio by applying fuzzy-set Qualitative Comparative Analysis (fsQCA). This methodology is renowned for its capacity to elucidate complex causal configurations within complex systems. Our methodological rationale for adopting fsQCA resides in its inherent suitability for accommodating the intricacies inherent in our research objectives. This allows us to create a deeper understanding and comprehension of the conditional interplays driving business service portfolio orchestration.","","en","book chapter","Springer International Publishing","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-27","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:e163be5c-664a-4a73-84e7-e87b364838ff","http://resolver.tudelft.nl/uuid:e163be5c-664a-4a73-84e7-e87b364838ff","Positioning Business Services","Plugge, A.G. (TU Delft Responsible Marketing and Consumer Behavior); Nikou, S. (TU Delft Responsible Marketing and Consumer Behavior)","Plugge, Albert (editor); Nikou, Shahrokh (editor)","2024","This chapter addresses the positioning of business services from three different perspectives. First, we describe the increasing demand and rise of business services and corresponding delivery modes. Second, we address the growth and position of global business services and their multi-nature. Next, we address GBS implementation challenges specifically. Fourth, we describe the importance of digitalisation as a means to overcome global business services implementation challenges. Finally, we summarise this chapter by addressing the key findings on business services.","","en","book chapter","Springer International Publishing","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-27","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:e2506e5b-7623-4c68-9f10-e9355fa76e58","http://resolver.tudelft.nl/uuid:e2506e5b-7623-4c68-9f10-e9355fa76e58","Case Study 2: Employment Agency","Plugge, A.G. (TU Delft Responsible Marketing and Consumer Behavior); Nikou, S. (TU Delft Responsible Marketing and Consumer Behavior)","Plugge, Albert (editor); Nikou, Shahrokh (editor)","2024","In this chapter we describe the second case study, which is a global operating employment agency. We first outline the context of the employment agency. Next, we describe how the agency established their Financial Shared Service Centre (FSSC). Then, the antecedents that are part of our research will be elaborated. As a final step, the analyses of the findings and concluding remarks will be presented.","","en","book chapter","Springer International Publishing","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-27","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:802aabfe-cbb3-4554-91c1-724e8dd74a25","http://resolver.tudelft.nl/uuid:802aabfe-cbb3-4554-91c1-724e8dd74a25","Case Study 3: Construction and Building Company","Plugge, A.G. (TU Delft Responsible Marketing and Consumer Behavior); Nikou, S. (TU Delft Responsible Marketing and Consumer Behavior)","Plugge, Albert (editor); Nikou, Shahrokh (editor)","2024","In this chapter we discuss a global construction and building enterprise. The context of the case company will be outlined, and then we describe how the company established their Financial Shared Service Centre (FSSC). At the end of this chapter, the antecedents that are part of the research will be explored and elaborated, and the analyses of the findings and concluding remarks will be presented.","","en","book chapter","Springer International Publishing","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-27","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:3330558a-127e-4141-9f6f-60653f5fbe1d","http://resolver.tudelft.nl/uuid:3330558a-127e-4141-9f6f-60653f5fbe1d","Cross-Case Analysis","Plugge, A.G. (TU Delft Responsible Marketing and Consumer Behavior); Nikou, S. (TU Delft Responsible Marketing and Consumer Behavior)","Plugge, Albert (editor); Nikou, Shahrokh (editor)","2024","Based on the empirical descriptive results of the four case studies, we relate our findings to the antecedents as described in Chap. 4. Our cross-case analysis comprises of four sections. First, we analyse the antecedents as used in our research model. In addition, we compare the cross-case findings with the outcomes of our fsQCA analysis in Chap. 5. Second, we discuss and show how we use Resource Orchestration Theory (ROT) as a theoretical lens to analyse and explain our findings. Third, we theorise on how enterprises may apply an ecosystem approach to orchestrate the studied antecedents in a coherent manner. Finally, we summarise our findings and provide cross-case study conclusions.","","en","book chapter","Springer International Publishing","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-27","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:5d908d5f-adbb-45b9-841c-9d4cb60876ff","http://resolver.tudelft.nl/uuid:5d908d5f-adbb-45b9-841c-9d4cb60876ff","Case Study 4: Financial Services Provider","Plugge, A.G. (TU Delft Responsible Marketing and Consumer Behavior); Nikou, S. (TU Delft Responsible Marketing and Consumer Behavior)","Plugge, Albert (editor); Nikou, Shahrokh (editor)","2024","In this chapter, we describe the fourth case study, which is a global operating service provider specialised in financial services. We first sketch out the context of the service provider, and next, describe how they established the delivery of financial business services (FSSC). Then, we elaborate on the antecedents that are part of our research. As a final step, we analyse the findings and summarise our conclusions.","","en","book chapter","Springer International Publishing","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-27","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:0426f78d-5df0-4fe0-8f71-6fc5ead33d00","http://resolver.tudelft.nl/uuid:0426f78d-5df0-4fe0-8f71-6fc5ead33d00","Time-of-day perception in paintings","Yu, C. (TU Delft Human Information Communication Design); Van Zuijlen, Mitchell J.P. (Kyoto University); Spoiala, C. (TU Delft Human Information Communication Design); Pont, S.C. (TU Delft Human Information Communication Design); Wijntjes, M.W.A. (TU Delft Human Information Communication Design); Hurlbert, Anya (Newcastle University)","","2024","The spectral shape, irradiance, direction, and diffuseness of daylight vary regularly throughout the day. The variations in illumination and their effect on the light reflected from objects may in turn provide visual information as to the time of day. We suggest that artists' color choices for paintings of outdoor scenes might convey this information and that therefore the time of day might be decoded from the colors of paintings. Here we investigate whether human viewers' estimates of the depicted time of day in paintings correlate with their image statistics, specifically chromaticity and luminance variations. We tested time-of-day perception in 17th- to 20th-century Western European paintings via two online rating experiments. In Experiment 1, viewers' ratings from seven time choices varied significantly and largely consistently across paintings but with some ambiguity between morning and evening depictions. Analysis of the relationship between image statistics and ratings revealed correlations with the perceived time of day: higher ""morningness"" ratings associated with higher brightness, contrast, and saturation and darker yellow/brighter blue hues; ""eveningness"" with lower brightness, contrast, and saturation and darker blue/brighter yellow hues. Multiple linear regressions of extracted principal components yielded a predictive model that explained 76% of the variance in time-of-day perception. In Experiment 2, viewers rated paintings as morning or evening only; rating distributions differed significantly across paintings, and image statistics predicted people's perceptions. These results suggest that artists used different color palettes and patterns to depict different times of day, and the human visual system holds consistent assumptions about the variation of natural light depicted in paintings.","OA-Fund TU Delft","en","journal article","","","","","","","","","","","Human Information Communication Design","","",""
"uuid:eb921c44-7692-4453-ba28-d43c8330307e","http://resolver.tudelft.nl/uuid:eb921c44-7692-4453-ba28-d43c8330307e","Goal-adaptive Meshing of Isogeometric Kirchhoff–Love Shells","Verhelst, H.M. (TU Delft Ship and Offshore Structures; TU Delft Numerical Analysis); Mantzaflaris, A. (University Côte d'Azur); Möller, M. (TU Delft Numerical Analysis); den Besten, J.H. (TU Delft Ship and Offshore Structures)","","2024","Mesh adaptivity is a technique to provide detail in numerical solutions without the need to refine the mesh over the whole domain. Mesh adaptivity in isogeometric analysis can be driven by Truncated Hierarchical B-splines (THB-splines) which add degrees of freedom locally based on finer B-spline bases. Labeling of elements for refinement is typically done using residual-based error estimators. In this paper, an adaptive meshing workflow for isogeometric Kirchhoff–Love shell analysis is developed. This framework includes THB-splines, mesh admissibility for combined refinement and coarsening and the Dual-Weighted Residual (DWR) method for computing element-wise error contributions. The DWR can be used in several structural analysis problems, allowing the user to specify a goal quantity of interest which is used to mark elements and refine the mesh. This goal functional can involve, for example, displacements, stresses, eigenfrequencies etc. The proposed framework is evaluated through a set of different benchmark problems, including modal analysis, buckling analysis and non-linear snap-through and bifurcation problems, showing high accuracy of the DWR estimator and efficient allocation of degrees of freedom for advanced shell computations.","Adaptive meshing; Buckling; Dual-weighted residual method; Isogeometric analysis; Kirchhoff–Love shell","en","journal article","","","","","","","","","","","Ship and Offshore Structures","","",""
"uuid:682a5325-198b-4d77-a029-a39faff86ce5","http://resolver.tudelft.nl/uuid:682a5325-198b-4d77-a029-a39faff86ce5","Water renewal and stratification modelling in small estuaries","Slinger, J (TU Delft Policy Analysis; Rhodes University)","","2024","Water renewal and flushing in small, intermittently open or closed estuaries is receiving increasing attention particularly in light of the climate change induced alterations in run-off, wave and sediment transport conditions along coasts. The challenges of predicting the stratification-circulation state and the balance between tidal or freshwater flushing in response to the mouth dynamics of small, wave-dominated estuaries is the focus of the paper. Such predictions are required for determining estuary freshwater requirements or establishing an estuary's capacity to maintain sound water quality under pollutant discharges. Advances in simulating changes in stratification-circulation over long time scales are limited. Instead attention has focused on generating indices of stratification or water quality state using heuristic methods. In this paper, systems dynamics modelling is applied to simulate the non-linear response of the estuary to changes in river and marine water fluxes. The estuary is modelled as a basin with a specified water volume to water level relationship, connected to the sea by a channel with variable sill height, but fixed width. The direction and magnitude of the flow through the mouth determines whether the sill height erodes or accretes and hence the mouth dynamics (see Slinger, 2017). The tidal flux through the mouth co-determines the volumetric exchange of salt, influencing both the stratification state of the estuary and the degree of tidal or freshwater flushing. This is also influenced by run-off. The resulting dynamic balance is captured in two bulk indices, the Estuarine Richardson number and the bulk densimetric Froude number. Using measured data from the Great Brak Estuary, South Africa, the model is calibrated. Model simulations demonstrate the importance of tidal flushing and concomitant mouth breaching for water renewal as freshwater flushing declines under scenarios of increased water abstraction. Although the estuary remains partially mixed, there is increased average salinity and a more uniform the water column. Water releases and mouth breaching bring about a more natural stratification-circulation state, but these effects are short-lived.","Freshwater flushing; Intermittent closed/open estuary; Parametric modelling; South Africa; Stratification-circulation state; Tidal flushing","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:d9904329-087a-4799-8327-e0159a30be88","http://resolver.tudelft.nl/uuid:d9904329-087a-4799-8327-e0159a30be88","Mixed-integer optimisation of graph neural networks for computer-aided molecular design","McDonald, Tom (Student TU Delft); Tsay, Calvin (Imperial College London); Schweidtmann, A.M. (TU Delft ChemE/Process Systems Engineering); Yorke-Smith, N. (TU Delft Algorithmics)","","2024","ReLU neural networks have been modelled as constraints in mixed integer linear programming (MILP), enabling surrogate-based optimisation in various domains and efficient solution of machine learning certification problems. However, previous works are mostly limited to MLPs. Graph neural networks (GNNs) can learn from non-euclidean data structures such as molecular structures efficiently and are thus highly relevant to computer-aided molecular design (CAMD). We propose a bilinear formulation for ReLU Graph Convolutional Neural Networks and a MILP formulation for ReLU GraphSAGE models. These formulations enable solving optimisation problems with trained GNNs embedded to global optimality. We apply our optimisation approach to an illustrative CAMD case study where the formulations of the trained GNNs are used to design molecules with optimal boiling points.","Graph neural networks; GraphSAGE; Mixed integer programming; Molecular design; Optimal boiling point","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-22","","","ChemE/Process Systems Engineering","","",""
"uuid:369651f0-4fe9-48da-9723-cb663c876a00","http://resolver.tudelft.nl/uuid:369651f0-4fe9-48da-9723-cb663c876a00","Integrity-based Explanations for Fostering Appropriate Trust in AI Agents","Mehrotra, S. (TU Delft Interactive Intelligence); Centeio Jorge, C. (TU Delft Interactive Intelligence); Jonker, C.M. (TU Delft Interactive Intelligence); Tielman, M.L. (TU Delft Interactive Intelligence)","","2024","Appropriate trust is an important component of the interaction between people and AI systems, in that ‘inappropriate’ trust can cause disuse, misuse or abuse of AI. To foster appropriate trust in AI, we need to understand how AI systems can elicit appropriate levels of trust from their users. Out of the aspects that influence trust, this paper focuses on the effect of showing integrity. In particular, this paper presents a study of how different integrity-based explanations made by an AI agent affect the appropriateness of trust of a human in that agent. To explore this, (1) we provide a formal definition to measure appropriate trust, (2) present a between-subject user study with 160 participants who collaborated with an AI agent in such a task. In the study, the AI agent assisted its human partner in estimating calories on a food plate by expressing its integrity through explanations focusing on either honesty, transparency or fairness. Our results show that (a) an agent who displays its integrity by being explicit about potential biases in data or algorithms achieved appropriate trust more often compared to being honest about capability or transparent about the decision-making process, and (b) subjective trust builds up and recovers better with honesty-like integrity explanations. Our results contribute to the design of agent-based AI systems that guide humans to appropriately trust them, a formal method to measure appropriate trust, and how to support humans in calibrating their trust in AI.","Intelligent Agents; HCI; Trust; Honesty; Appropriate Trust; Artificial Agents; Integrity; Explanations; Fairness; Transparency","en","journal article","","","","","","","","","","","Interactive Intelligence","","",""
"uuid:936ca2c8-2b62-4cf3-a334-7ddab99fbf94","http://resolver.tudelft.nl/uuid:936ca2c8-2b62-4cf3-a334-7ddab99fbf94","Mechanical Framework for Geopolymer Gels Construction: An Optimized LSTM Technique to Predict Compressive Strength of Fly Ash-Based Geopolymer Gels Concrete","Shi, Xuyang (China University of Mining and Technology); Chen, Shuzhao (China University of Mining and Technology); Wang, Qiang (China University of Mining and Technology); Lu, Yijun (Guangzhou University); Ren, S. (TU Delft Pavement Engineering); Huang, Jiandong (Guangzhou University)","","2024","As an environmentally responsible alternative to conventional concrete, geopolymer concrete recycles previously used resources to prepare the cementitious component of the product. The challenging issue with employing geopolymer concrete in the building business is the absence of a standard mix design. According to the chemical composition of its components, this work proposes a thorough system or framework for estimating the compressive strength of fly ash-based geopolymer concrete (FAGC). It could be possible to construct a system for predicting the compressive strength of FAGC using soft computing methods, thereby avoiding the requirement for time-consuming and expensive experimental tests. A complete database of 162 compressive strength datasets was gathered from the research papers that were published between the years 2000 and 2020 and prepared to develop proposed models. To address the relationships between inputs and output variables, long short-term memory networks were deployed. Notably, the proposed model was examined using several soft computing methods. The modeling process incorporated 17 variables that affect the CSFAG, such as percentage of SiO2 (SiO2), percentage of Na2O (Na2O), percentage of CaO (CaO), percentage of Al2O3 (Al2O3), percentage of Fe2O3 (Fe2O3), fly ash (FA), coarse aggregate (CAgg), fine aggregate (FAgg), Sodium Hydroxide solution (SH), Sodium Silicate solution (SS), extra water (EW), superplasticizer (SP), SH concentration, percentage of SiO2 in SS, percentage of Na2O in SS, curing time, curing temperature that the proposed model was examined to several soft computing methods such as multi-layer perception neural network (MLPNN), Bayesian regularized neural network (BRNN), generalized feed-forward neural networks (GFNN), support vector regression (SVR), decision tree (DT), random forest (RF), and LSTM. Three main innovations of this study are using the LSTM model for predicting FAGC, optimizing the LSTM model by a new evolutionary algorithm called the marine predators algorithm (MPA), and considering the six new inputs in the modeling process, such as aggregate to total mass ratio, fine aggregate to total aggregate mass ratio, FASiO2:Al2O3 molar ratio, FA SiO2:Fe2O3 molar ratio, AA Na2O:SiO2 molar ratio, and the sum of SiO2, Al2O3, and Fe2O3 percent in FA. The performance capacity of LSTM-MPA was evaluated with other artificial intelligence models. The results indicate that the R2 and RMSE values for the proposed LSTM-MPA model were as follows: MLPNN (R2 = 0.896, RMSE = 3.745), BRNN (R2 = 0.931, RMSE = 2.785), GFFNN (R2 = 0.926, RMSE = 2.926), SVR-L (R2 = 0.921, RMSE = 3.017), SVR-P (R2 = 0.920, RMSE = 3.291), SVR-S (R2 = 0.934, RMSE = 2.823), SVR-RBF (R2 = 0.916, RMSE = 3.114), DT (R2 = 0.934, RMSE = 2.711), RF (R2 = 0.938, RMSE = 2.892), LSTM (R2 = 0.9725, RMSE = 1.7816), LSTM-MPA (R2 = 0.9940, RMSE = 0.8332), and LSTM-PSO (R2 = 0.9804, RMSE = 1.5221). Therefore, the proposed LSTM-MPA model can be employed as a reliable and accurate model for predicting CSFAG. Noteworthy, the results demonstrated the significance and influence of fly ash and sodium silicate solution chemical compositions on the compressive strength of FAGC. These variables could adequately present variations in the best mix designs discovered in earlier investigations. The suggested approach may also save time and money by accurately estimating the compressive strength of FAGC with low calcium content.","long short-term memory networks; compressive strength; prediction; marine predators algorithm","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:538af6ba-2ff0-477b-886f-9ad68d63ee04","http://resolver.tudelft.nl/uuid:538af6ba-2ff0-477b-886f-9ad68d63ee04","Towards a Reliable Design of Geopolymer Concrete for Green Landscapes: A Comparative Study of Tree-Based and Regression-Based Models","Wang, Ranran (Guangzhou University); Zhang, Jun (Guangzhou University); Lu, Yijun (Guangzhou University); Ren, S. (TU Delft Pavement Engineering); Huang, Jiandong (Guangzhou University)","","2024","The design of geopolymer concrete must meet more stringent requirements for the landscape, so understanding and designing geopolymer concrete with a higher compressive strength challenging. In the performance prediction of geopolymer concrete compressive strength, machine learning models have the advantage of being more accurate and faster. However, only a single machine learning model is usually used at present, there are few applications of ensemble learning models, and model optimization processes is lacking. Therefore, this paper proposes to use the Firefly Algorithm (AF) as an optimization tool to perform hyperparameter tuning on Logistic Regression (LR), Multiple Logistic Regression (MLR), decision tree (DT), and Random Forest (RF) models. At the same time, the reliability and efficiency of four integrated learning models were analyzed. The model was used to analyze the influencing factors of geopolymer concrete and determine the strength of their influencing ability. According to the experimental data, the RF-AF model had the lowest RMSE value. The RMSE value of the training set and test set were 4.0364 and 8.7202, respectively. The R value of the training set and test set were 0.9774 and 0.8915, respectively. Therefore, compared with the other three models, RF-AF has a stronger generalization ability and higher prediction accuracy. In addition, the molar concentration of NaOH was the most important influencing factors, and its influence was far greater than the other possible factors including NaOH content. Therefore, it is necessary to pay more attention to NaOH molarity when designing geopolymer concrete.","ensemble learning model; beetle antennae search; geopolymer concrete; NaOH molarity","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:1e25451e-f642-481e-9e1b-e293e969ff0b","http://resolver.tudelft.nl/uuid:1e25451e-f642-481e-9e1b-e293e969ff0b","Nanostructure and damage characterisation of bitumen under a low cycle strain-controlled fatigue load based on molecular simulations and rheological measurements","Gao, Y. (Liverpool John Moores University); Liu, X. (TU Delft Pavement Engineering); Ren, S. (TU Delft Pavement Engineering); Assaf Martinez-Streignard, E.I. (TU Delft Pavement Engineering); Liu, Pengfei (Rheinisch-Westfälische Technische Hochschule); Zhang, Yuqing (Southeast University)","","2024","Bitumen fatigue resistance is critical to determine the overall fatigue performance and service life of asphalt pavements. However, the mechanisms responsible for fatigue damage of bitumen have previously not been well understood. Molecular dynamics (MD) simulation has recently emerged as a powerful computer-aided numerical technique to model the microscopic failure behaviours in materials. This study aims to use the MD method to investigate the molecular origin of bitumen fatigue damage. The molecular models of the virgin and aged PEN70/100 bitumen were firstly constructed based on their saturate, aromatic, resin and asphaltene (SARA) four fractions. An MD equilibrium was run on the developed bitumen models with the assigned interatomic potentials. Following an MD-based tensile simulation, a strain-controlled fatigue simulation was performed to study the nanostructure and damage behaviours of the virgin and aged bitumen under fatigue loading by calculating the stress-strain response, potential energy, molecular structure and nanovoid volumes. Furthermore, a rheometer measurement was also conducted to characterise the fatigue damage of the bitumen directly by a crack length at the macroscale. Results indicate that the bitumen molecules become unfolded and tend to align along the loading direction when fatigue loading was applied. The change in the molecular configuration helped the molecular chains move closer together and thus contributed to the reduction of the intermolecular interactions including the van der Waals and Coulombic energies. With the increasing load cycles, nanovoids were formed and grew in the bitumen through molecular rearrangement and movement, leading to microscopic fatigue damage of the bitumen. It was found that the aged bitumen produced more severe fatigue damage than the virgin bitumen, which was indicated by the MD-based nanovoid volume at the molecular scale and the DSR-based crack length at the macroscale. The findings from MD simulation provide a fundamental understanding of the molecular origin of fatigue damage, that cannot be experimentally detected for bitumen materials.","Bitumen; Fatigue damage; Nanostructure; MD simulation; Rheometer measurement","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:2b4273b0-0729-4473-af1e-5c2e87679ee3","http://resolver.tudelft.nl/uuid:2b4273b0-0729-4473-af1e-5c2e87679ee3","RAP pre-treatment for fast cold in-place recycling","Lin, P. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Ren, S. (TU Delft Pavement Engineering); Li, Yi (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Welvaarts, B. (De Jong Zuurmond); Brouns, K. (De Jong Zuurmond)","Zhang, Yuqing (editor); Airey, Gordon (editor); Rahman, Mujib (editor); Wang, Haopeng (editor)","2024","Developed by Delft University of Technology, the tri-component polyurethane modified cold binder (PMCB) displays impressive durability and strength in asphalt mixtures, showing promise as a reliable binder for cold in-place recycling. However, when applying PMCB for rapid, in-situ recycling, the presence of moisture in reclaimed asphalt pavement (RAP) poses a significant challenge. To address this, an innovative approach involving treatment of the wet RAP with Calcium dioxide (CaO) prior to the integration of PMCB was tested. Evaluation methods used included the Indirect Tensile Test (ITT), followed by the calculation of the Indirect Tensile Strength Ratio (ITSR) to assess moisture susceptibility. Furthermore, Cantabro tests were performed to determine the material loss under abrasion and weathering conditions. These assessments underscored the feasibility of this approach. The treatment of wet RAP with CaO has proven a viable strategy for rapid in-situ recycling with PMCB, contributing to sustainable pavement construction. In addition, the research identified that a 5.5% concentration of the PMCB binder maximizes structural integrity and performance in the considered RAP.","","en","conference paper","CRC Press / Balkema - Taylor & Francis Group","","","","","","","2024-06-01","","","Pavement Engineering","","",""
"uuid:249cc9ee-b86d-4125-a4c7-253139b10467","http://resolver.tudelft.nl/uuid:249cc9ee-b86d-4125-a4c7-253139b10467","Stability analysis and energy harvesting in lumped parameter systems with internally coupled resonators","Alimohammadi, Hossein (Tallinn University of Technology); Vassiljeva, Kristina (Tallinn University of Technology); Hassan HosseinNia, S. (TU Delft Mechatronic Systems Design); Petlenkov, Eduard (Tallinn University of Technology)","","2024","This article explores internally coupled resonators in metamaterial systems, focusing on mechanical and electromechanical coupling. The article provides a thorough examination of stability within the context of internally coupled resonators. It establishes stability criteria, emphasizing the importance of strictly stable systems in practical applications. Furthermore, it analyzes stability through simulations, revealing how various parameters impact system behavior and highlighting the challenges and benefits of achieving stability in metamaterial systems. Additionally, the article explores the impact of damping coefficients and resonator characteristics, on displacement and power generation profiles. Nonlinear behavior in internally coupled resonators is examined, revealing the presence of bifurcation in simulation and offering insights into multi-stability and system behavior.","internally coupled resonators; lumped systems; piezoelectric energy harvesting; stability; vibration suppression","en","journal article","","","","","","","","","","","Mechatronic Systems Design","","",""
"uuid:ae8d823f-d967-4a2a-8ae1-5baa2a348215","http://resolver.tudelft.nl/uuid:ae8d823f-d967-4a2a-8ae1-5baa2a348215","Rolling pairs with shifting contact geometry: Design, development, and validation","Amoroso, Pedro (TU Delft Mechatronic Systems Design; University of Twente); van Ostayen, R.A.J. (TU Delft Mechatronic Systems Design); de Rooij, Matthijn B. (University of Twente)","","2024","This work introduces two innovative rolling pair concepts to minimize slippage and reduce mass in cam-roller systems of large-scale hydraulic drivetrains: The variable contact length and the Shifting Contact Geometry concepts. Both aim to improve traction in the low contact force phase in cyclically loaded rolling contacts. The shifting contact geometry concept was validated using three custom rolling contacts: a line contact, a double elliptical contact, and a combination of both (i.e., shifting contact geometry). The tests were conducted under synchronized cyclic loading to mimic the conditions in a hydraulic drivetrain. Furthermore, a model from previous work was implemented to make predictions and compare them against the experimental results. During preliminary tests, the double elliptical contact displayed superior tractive behavior than the line contact under the same load thanks to higher contact pressures. Under synchronized cyclic loading, the line contact displayed high sensitivity to applied resisting torques at low contact forces, leading to high slide-to-roll ratios and traction force peaks. In contrast, the rolling pair with shifting contact geometry exhibited minimum slippage even under high resisting torques, resulting in substantially lower (and in most cases negligible) slide-to-roll ratio and traction force peaks. The simulations also captured this behavior, proving the validity of the model for predicting and comparing the rolling-sliding dynamics of these two different rolling pairs. This study demonstrates that rolling pairs with shifting contact geometry can not only improve the tribological performance of cam-roller contacts in large-scale hydraulic drivetrains but also yield a more favorable dynamic behavior.","cam; drivetrain; elliptical; geometry; hydraulic; Large; line; roller; rolling; scale; shifting; sliding; slippage; traction","en","journal article","","","","","","Accepted Author Manuscript","","","","","Mechatronic Systems Design","","",""
"uuid:9d50fe88-ca05-4c00-9018-1139850b3f55","http://resolver.tudelft.nl/uuid:9d50fe88-ca05-4c00-9018-1139850b3f55","Optimal parameter estimation of shaped phase objects","Villegas, Arturo (ICFO-Institut de Ciencies Fotoniques; Centre Tecnològic de Telecomunicacions de Catalunya (CTTC/CERCA)); Passos, M. H.M. (ICFO-Institut de Ciencies Fotoniques); Pereira, S.F. (TU Delft ImPhys/Pereira group); Torres, J. (TU Delft Electrical Engineering, Mathematics and Computer Science; ICFO-Institut de Ciencies Fotoniques; Universitat Politecnica de Catalunya)","","2024","We show a general method to estimate with optimum precision, i.e., the best precision determined by the light-matter interaction process, a set of parameters that characterize a phase object. The method is derived from ideas presented by Pezze et al. [Phys. Rev. Lett. 119, 130504 (2017)0031-900710.1103/PhysRevLett.119.130504]. Our goal is to illuminate the main characteristics of this method as well as its applications to the physics community probably not familiar with the formal quantum language usually employed in works related to quantum estimation theory. First, we derive precision bounds for the estimation of the set of parameters characterizing the phase object. We compute the Crámer-Rao lower bound for two experimentally relevant types of illumination: a multimode coherent state with mean photon number N and N copies of a multimode single-photon quantum state. We show under which conditions these two models are equivalent. Second, we show that the optimum precision can be achieved by projecting the light reflected or transmitted from the object onto a set of modes with engineered spatial shape. We describe how to construct these modes and demonstrate explicitly that the precision of the estimation using these measurements is optimum. As an example, we apply these results to the estimation of the height and sidewall angle of a cliff-like nanostructure, an object relevant in the semiconductor industry for the evaluation of nanofabrication techniques.","","en","journal article","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","ImPhys/Pereira group","","",""
"uuid:6eb5ac67-bc4b-42ea-8fde-3877d3c8705c","http://resolver.tudelft.nl/uuid:6eb5ac67-bc4b-42ea-8fde-3877d3c8705c","Conceptualising user comfort in automated driving: Findings from an expert group workshop","Peng, Chen (University of Leeds); Horn, Stefanie (University of Leeds; Robert Bosch GmbH); Madigan, Ruth (University of Leeds); Marberger, Claus (Robert Bosch GmbH); Lee, John D. (University of Wisconsin-Madison); Krems, Josef (Technische Universität Chemnitz); Beggiato, Matthias (Technische Universität Chemnitz); Romano, Richard (University of Leeds); Wei, Chongfeng (Queen's University Belfast); Wooldridge, Ellie (Transport Systems Catapult); Happee, R. (TU Delft Intelligent Vehicles); Hagenzieker, Marjan (TU Delft Transport and Planning); Merat, Natasha (University of Leeds)","","2024","The driving style of an automated vehicle (AV) needs to be comfortable to encourage the broad acceptance and use of this newly emerging transport mode. However, current research provides limited knowledge about what influences comfort, how this concept is described, and how it is measured. This knowledge is especially lacking when comfort is linked to the AV's driving styles. This paper presents results from an online workshop with nine experts, all with hands-on experience of AVs and a long track record of research in this context. Using online tools, experts were invited to introduce concepts they considered relevant to comfort/discomfort in currently available modes of transport which offer a ride (taxi/bus/train) to users and compare these to the concepts used to define comfort and discomfort in AVs. Results showed that a wide range of terms were used to describe user comfort and discomfort for both modes. Although all terms used for existing vehicles were found to apply to AVs, additional terms were proposed for determining comfort/discomfort of AVs. For example, to enhance comfort in AVs, designers should consider good communication channels, as well as ensuring that the AV's capabilities match users’ expectations. Results also revealed that more terms were used, overall, to define discomfort, and that a comfortable ride in AVs is not just about mitigating discomfort. New concepts specific to AVs were also revealed when considering what increases their discomfort, such as whether riders’ safety and privacy are affected, or if they feel in control. Experts’ input from the workshop was used to enhance and expand a simple conceptual framework, explaining how AV driving styles, as well as other, non-driving-related factors, affect user comfort. It is hoped that this framework provides a more comprehensive list of the concepts affecting user comfort, also allowing more accurate measurement of the concept. As well as allowing for a more accurate comparison between empirical studies measuring comfort in AVs, this study will facilitate the design of more comfortable and acceptable automated driving for future vehicles.","Automated vehicles; Conceptual framework; Driving styles; Expert workshop; User comfort","en","journal article","","","","","","","","","","","Intelligent Vehicles","","",""
"uuid:eb9089db-0086-452d-b8e0-9496eb50f440","http://resolver.tudelft.nl/uuid:eb9089db-0086-452d-b8e0-9496eb50f440","Visitors’ perceptions of urban wilderness: A case study of Jiangyangfan Ecological Park in Hangzhou, China","Chen, Y. (TU Delft Landscape Architecture); Nijhuis, S. (TU Delft Landscape Architecture); van Dorst, M.J. (TU Delft Urban Studies)","","2024","Numerous studies show the benefits of wilderness to humans and the environment. Therefore, preserving and developing wilderness areas within urban settings are crucial to combat and mitigate challenges like biodiversity decline resulting from urbanization. According to previous studies, human-wilderness interactions can be contradictory, e.g., relaxing while feeling anxious and insecure. How individuals perceive and comprehend intentional urban wilderness, what dimensions contribute to their perceptions, and how these dimensions influence the visitors’ perceptions remain to be investigated. Selecting Jiangyangfan Ecological Park (Hangzhou, China) as a survey case, this research investigates if and how people perceive intentionally incorporated and designed urban wilderness and how various dimensions of attributes shape their perceptions. This study identified three dimensions that may contribute to visitors’ perceptions of the urban wilderness; namely, cognitive landscape attributes, perceived environmental attributes, and their visitation experience. A mixed-method approach was employed using a questionnaire, mental maps, and environmental behaviour observation as diverse data sources to assess visitors’ urban wilderness perceptions and comprehension from the three dimensions. Results indicate a high propensity to visit the park as an urban wilderness. Our findings also revealed that visitors’ perceptual environmental attributes, e.g., the existence of vegetation and waterbodies and encounters with wild animals, as well as their visit experiences, e.g., their satisfaction with the visit and their motivation for experiencing nature, significantly influence their perceptions. In contrast, prior knowledge and experience-based cognition of urban wilderness attributes showed no significant influence on their perceptions. Moreover, attributes like plant diversity, water visibility, and plant density emerged as critical factors shaping visitors’ perceptions. These findings underscore the importance of considering visitors’ on-site perception of environmental attributes and actual visit experience when assessing the value and acceptability of urban wilderness areas. Future implications of this study for urban wilderness planning and management were also discussed.","Case study; Environmental perception; Landscape planning and design; Urban wilderness","en","journal article","","","","","","","","","","","Landscape Architecture","","",""
"uuid:73491ad5-d288-48a6-8dfd-5454ad5a7318","http://resolver.tudelft.nl/uuid:73491ad5-d288-48a6-8dfd-5454ad5a7318","Impact of Transforming Interface Geometry on Edge States in Valley Photonic Crystals","Yu, D. (Kavli institute of nanoscience Delft; Student TU Delft); Arora, S. (Kavli institute of nanoscience Delft; Student TU Delft); Kuipers, L. (TU Delft QN/Quantum Nanoscience; Kavli institute of nanoscience Delft)","","2024","We investigate how altering the interface geometry from a zigzag to a glide plane interface between two topologically distinct valley Hall emulating photonic crystals (VPC), profoundly affects edge states. We experimentally observe a transition from gapless to gapped edge states, accompanied by the occurrence of slow light within the Brillouin zone, rather than at its edge. We numerically simulate the propagation and measure the transmittance of the modified edge states through a specially designed valley-conserving defect. The robustness to backscattering gradually decreases, suggesting a disruption of valley-dependent transport. We demonstrate the significance of interface geometry to gapless edge states in a VPC.","","en","journal article","","","","","","","","","","QN/Quantum Nanoscience","","","",""
"uuid:dde37837-c197-4f8f-93bb-11775a9e740a","http://resolver.tudelft.nl/uuid:dde37837-c197-4f8f-93bb-11775a9e740a","Thermal Stability of F-Rich Phlogopite and K-Richterite During Partial Melting of Metasomatized Mantle Peridotite With Implications for Deep Earth Volatile Cycles","Steenstra, E.S. (TU Delft Planetary Exploration; University of Münster); Klaver, M. (University of Münster); Berndt, J. (University of Münster); Flemetakis, S. (University of Münster; ETH Zürich); Rohrbach, A. (University of Münster); Klemme, S. (University of Münster)","","2024","Phlogopite and K-richterite constitute important carrier phases for H and F in Earth's lithosphere and mantle. The relative importance depends on their stabilities at high pressure and temperature, which in turn depends on bulk composition. Most previous experimental studies focused on the thermal stability of phlogopite and K-richterite were conducted using simplified chemical compositions. Here, partial melting experiments on metasomatized and carbonated, OH ± F-bearing near-natural peridotite were performed at high pressures (2 and 5 GPa) and temperatures (1,100–1,350°C) to assess the thermal stability of F-free versus F-bearing phlogopite and K-richterite. Experimental results demonstrate that the thermal stability of F-bearing phlogopite is increased by >55°C/wt.% F, relative to F-free phlogopite, whereas K-richterite is absent in all experiments with significant degrees of melting (>2%). The thermal stability of phlogopite containing several wt.% F exceeds continental and oceanic geotherms within the upper 150 km. Fluorine-rich phlogopite would therefore be stable in virtually all of the continental lithosphere, only to be decomposed during large, regional melting events such as continental break-up, thereby acting as a major long-term sink for F and/or H. This could even be the case for the oceanic asthenosphere, depending on the oceanic geotherm of the area of interest.","fluorine; hydrogen; metasomatism; partial melting; peridotite; volatiles","en","journal article","","","","","","","","","","","Planetary Exploration","","",""
"uuid:ce22c247-27e3-46ea-a05d-55c720c35085","http://resolver.tudelft.nl/uuid:ce22c247-27e3-46ea-a05d-55c720c35085","The OPS-SAT case: A data-centric competition for onboard satellite image classification","Meoni, G. (TU Delft Space Systems Egineering; European Space Agency (ESA)); Märtens, Marcus (European Space Agency (ESA)); Derksen, Dawa (European Space Agency (ESA)); See, Kenneth (Inovor Technologies); Lightheart, Toby (Inovor Technologies); Sécher, Anthony (Capgemini Engineering–Hybrid Intelligence); Martin, Arnaud (Capgemini Engineering–Hybrid Intelligence); Rijlaarsdam, David (DCU); Fanizza, Vincenzo (DCU); Izzo, Dario (European Space Agency (ESA))","","2024","While novel artificial intelligence and machine learning techniques are evolving and disrupting established terrestrial technologies at an unprecedented speed, their adaptation onboard satellites is seemingly lagging. A major hindrance in this regard is the need for high-quality annotated data for training such systems, which makes the development process of machine learning solutions costly, time-consuming, and inefficient. This paper presents “the OPS-SAT case”, a novel data-centric competition that seeks to address these challenges. The powerful computational capabilities of the European Space Agency’s OPS-SAT satellite are utilized to showcase the design of machine learning systems for space by using only the small amount of available labeled data, relying on the widely adopted and freely available open-source software. The generation of a suitable dataset, design and evaluation of a public data-centric competition, and results of an onboard experimental campaign by using the competition winners’ machine learning model directly on OPS-SAT are detailed. The results indicate that adoption of open standards and deployment of advanced data augmentation techniques can retrieve meaningful onboard results comparatively quickly, simplifying and expediting an otherwise prolonged development period. (Figure presented.).","artificial intelligence (AI); data-centric competition; onboard classification; onboard machine learning; OPS-SAT","en","journal article","","","","","","","","","","","Space Systems Egineering","","",""
"uuid:aa737d12-e94d-43eb-9713-9c93ddb88edc","http://resolver.tudelft.nl/uuid:aa737d12-e94d-43eb-9713-9c93ddb88edc","Implementation and Evaluation of a Motivational Robotic Coach for Repetitive Stroke Rehabilitation","Ross, Martin K. (Heriot-Watt University); Broz, F. (TU Delft Interactive Intelligence); Baillie, Lynne (Heriot-Watt University)","","2024","Repetitive, individual exercises can improve the functional ability of stroke survivors over the long term. With the aim of providing extra motivation to adhere to repetitive, individual rehabilitation, this paper presents a robotic coach for stroke rehabilitation. Our system uses the Pepper robot and performs one of twelve data-driven coaching policies. The policies were learned from human-human observations of professional stroke physiotherapists and provide high-level personalisation based on user information and training context. A within subjects evaluation of the system was conducted in-person involving short interactions with 3 stroke survivors. The system was able to engage the target end users and there were indications that decreased workload could be possible when using the system compared to exercising alone.","Coaching; Personalisation; Rehabilitation; Stroke","en","conference paper","IEEE","","","","","","","","","","Interactive Intelligence","","",""
"uuid:978d6ed5-51d4-4919-9659-c7f5fdfd5c3c","http://resolver.tudelft.nl/uuid:978d6ed5-51d4-4919-9659-c7f5fdfd5c3c","Bloom weighted bounds for sparse forms associated to commutators","Lerner, Andrei K. (Bar-Ilan University); Lorist, E. (TU Delft Analysis); Ombrosi, Sheldy (Universidad Complutense de Madrid; UNS-CONICET San Andres 800)","","2024","In this paper we consider bilinear sparse forms intimately related to iterated commutators of a rather general class of operators. We establish Bloom weighted estimates for these forms in the full range of exponents, both in the diagonal and off-diagonal cases. As an application, we obtain new Bloom bounds for commutators of (maximal) rough homogeneous singular integrals and the Bochner–Riesz operator at the critical index. We also raise the question about the sharpness of our estimates. In particular we obtain the surprising fact that even in the case of Calderón–Zygmund operators, the previously known quantitative Bloom bounds are not sharp for the second and higher order commutators.","42B20; 42B25; 47B47; Bilinear sparse forms; Bloom weighted bounds; Iterated commutators","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:f5673e6b-2539-4e65-8d37-f9bc51900f0e","http://resolver.tudelft.nl/uuid:f5673e6b-2539-4e65-8d37-f9bc51900f0e","Enhanced Real-Time Multi-Terminal HVDC Power System Benchmark Models with Performance Evaluation Strategies","Shetgaonkar, A.D. (TU Delft Intelligent Electrical Power Grids); Karmokar, T.R. (TU Delft Intelligent Electrical Power Grids; TenneT TSO B.V.); Popov, M. (TU Delft Intelligent Electrical Power Grids); Lekić, A. (TU Delft Intelligent Electrical Power Grids)","","2024","Real-time simulations have become a crucial tool for life cycle studies of VSC-based HVDC systems. This paper introduces real-time Multi-Terminal HVDC (MTDC) power [1] system network models with real-time wind pro le feedback. It addresses the shortcomings of existing benchmark network models and lls the modeling gaps. ® RSCAD/RTDS environment represents the real-time modeling techniques for studying the life cycle of Bipolar Metallic Return con guration of HVDC systems. This paper evaluates the performance of the proposed network model using unscheduled events, startup, and black start events. Future studies can be conducted using the proposed network models by mimicking the actual performance of cable-based DC grids while considering the computational insights from this paper. The ndings of this paper shall enable the identi cation of various stress points that can be utilized to specify technical requirements for component design and AC/DC protection studies concerning startup and black start sequence.","AC/DC Protection; Metallic Return; Multi-Terminal DC; RTS model; SIL","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-31","","","Intelligent Electrical Power Grids","","",""
"uuid:6b4ecee4-1ff9-4b46-8f7c-e45a162841b1","http://resolver.tudelft.nl/uuid:6b4ecee4-1ff9-4b46-8f7c-e45a162841b1","Pentamodes: Effect of unit cell topology on mechanical properties","Mohammadi, Kaivan (Sharif University of Technology); Shafia, Moein (Sharif University of Technology); Akbari, Javad (Sharif University of Technology); Hedayati, R. (TU Delft Novel Aerospace Materials)","","2024","Pentamodes (first conceived theoretically by Milton and Cherkaev) are a very interesting class of mechanical metamaterials that can be used as building blocks of structures withdecoupled bulk and shear moduli. The pentamodes usually are composed of double cone-shaped struts with the middle diameter being large and the end diameters being tiny (ideally approaching zero). The cubic diamond geometry was proposed by Milton and Cherkaev as a suitable geometry for the unit cell and has since been used in the majority of the works on pentamodes. In this work, we aim to evaluate the degree to which the base unit cell design contributes to high bulk to shear modulus ratio, also known as Figure Of Merit(FOM). In addition to the diamond unit cell, three other well-known unit cell types are considered, and the effect of small diameter size and the ratio of large-to-small diameter, α, on the FOM is evaluated. The results showed that regardless of the base unit cell shape, the FOM value is highly dependent on the d (the smaller diameter size of double-cone) value, while its dependence on the D (the greater diameter of double-cone) value is very weak. For d/h∝0.05 (h representing the linkage length), figures of merit in the range of 103 could be reached for all the studied topologies.","3D printing; Meta-fluids; Metamaterials; Pentamodes","en","journal article","","","","","","","","","","","Novel Aerospace Materials","","",""
"uuid:d1516746-5d44-4d8f-bdb6-6faa7674be81","http://resolver.tudelft.nl/uuid:d1516746-5d44-4d8f-bdb6-6faa7674be81","Editorial: Special Issue on Human in the Loop Data Curation","Demartini, Gianluca (University of Queensland); Sadiq, Shazia (University of Queensland); Yang, J. (TU Delft Web Information Systems)","","2024","This Special Issue of the Journal of Data and Information Quality (JDIQ) contains novel theoretical and methodological contributions on data curation involving humans in the loop. In this editorial, we summarize the scope of the issue and briefly describe its content.","Additional Key Words and Phrases; crowdsourcing; data curation; Data quality; human in the loop","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-23","","","Web Information Systems","","",""
"uuid:806232b6-879f-4411-acaf-bff1f9df4569","http://resolver.tudelft.nl/uuid:806232b6-879f-4411-acaf-bff1f9df4569","Correction to: The potential of an adaptive computerized dynamic assessment tutor in diagnosing and assessing learners’ listening comprehension (Education and Information Technologies, (2024), 29, 3, (3637-3661), 10.1007/s10639-023-11871-w)","Izadi, Mehri (University of Sistan and Baluchestan); Izadi, M. (TU Delft Software Engineering); Heidari, Farrokhlagha (University of Sistan and Baluchestan)","","2024","In the PDF of this article, the pages were incorrectly numbered as ‘2303–2327’ when it should have been ‘3637–3661’. The page range was found to be just correct in the HTML version of the article. The original article has been corrected.","","en","journal article","","","","","","","","","","","Software Engineering","","",""
"uuid:e5732642-1040-42c1-adc2-2dd3c96c4353","http://resolver.tudelft.nl/uuid:e5732642-1040-42c1-adc2-2dd3c96c4353","Reconstitution of cytolinker-mediated crosstalk between actin and vimentin","Istúriz Petitjean, I. (TU Delft BN/Gijsje Koenderink Lab; Kavli institute of nanoscience Delft); Tran, Quang D. (Université Paris Cité); Goutou, A. (TU Delft BN/Gijsje Koenderink Lab; TU Delft BN/Cees Dekker Lab; Kavli institute of nanoscience Delft); Kabir, Z. (TU Delft BN/Gijsje Koenderink Lab; Kavli institute of nanoscience Delft); Wiche, Gerhard (University of Vienna); Leduc, Cécile (Université Paris Cité); Koenderink, G.H. (TU Delft BN/Gijsje Koenderink Lab; Kavli institute of nanoscience Delft)","","2024","Cell shape and motility are determined by the cytoskeleton, an interpenetrating network of actin filaments, microtubules, and intermediate filaments. The biophysical properties of each filament type individually have been studied extensively by cell-free reconstitution. By contrast, the interactions between the three cytoskeletal networks are relatively unexplored. They are coupled via crosslinkers of the plakin family such as plectin. These are challenging proteins for reconstitution because of their giant size and multidomain structure. Here we engineer a recombinant actin-vimentin crosslinker protein called ‘ACTIF’ that provides a minimal model system for plectin, recapitulating its modular design with actin-binding and intermediate filament-binding domains separated by a coiled-coil linker for dimerisation. We show by fluorescence and electron microscopy that ACTIF has a high binding affinity for vimentin and actin and creates mixed actin-vimentin bundles. Rheology measurements show that ACTIF-mediated crosslinking strongly stiffens actin-vimentin composites. Finally, we demonstrate the modularity of this approach by creating an ACTIF variant with the intermediate filament binding domain of Adenomatous Polyposis Coli. Our protein engineering approach provides a new cell-free system for the biophysical characterization of intermediate filament-binding crosslinkers and for understanding the mechanical synergy between actin and vimentin in mesenchymal cells.","Binding kinetics; Cytoskeleton; Plakins; Plectin; Rheology","en","journal article","","","","","","","","","","","BN/Gijsje Koenderink Lab","","",""
"uuid:da101444-7245-47e5-ae29-83599219ea86","http://resolver.tudelft.nl/uuid:da101444-7245-47e5-ae29-83599219ea86","Strengths, weaknesses, opportunities and threats of demand response in district heating and cooling systems. From passive customers to valuable assets","Marszal-Pomianowska, Anna (Aalborg University); Motoasca, Emilia (Flemish Institute for Technological Research); Pothof, I.W.M. (TU Delft Sanitary Engineering); Felsmann, Clemens (Technische Universität Dresden); Heiselberg, Per (Aalborg University); Cadenbach, Anna (Fraunhofer Institute for Energy Economics and Energy System Technology IEE); Leusbrock, Ingo (AEE – Institute for Sustainable Technologies); O'Donovan, Keith (AEE – Institute for Sustainable Technologies); Petersen, Steffen (Aarhus University); Schaffer, Markus (Aalborg University)","","2024","Buildings can deliver short-term thermal energy storage by utilising the thermal capacity of the building construction and/or by activating the water tanks included in the heating/cooling installation. The flexibility potential of demand management using decentralized thermal energy storage has been quantified in many theoretical modelling studies, and it is considered an essential technology for an affordable energy transition. We have investigated the drivers and barriers to the adoption of demand management in buildings in district heating and cooling systems via a Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis and presented 17 elements that shape the current and future application of this concept. The results indicate that the application of the DR concept has left the theoretical studies and moved towards real-life applications. Yet, there is a lack of feasible business models and regulatory frameworks supporting the large-scale application of the concept. Utilities and their customers do not fully understand the benefits of the DR concept; therefore they are reluctant to adopt it outside of the research projects where the test environment is fully controlled and with limited impact and timeline. Therefore, the regulatory framework must be adjusted to allow DHC operators to develop new business models and DR tariffs that will incentivise the customers to deliver flexibility to the system without compromising their comfort and everyday practices and increasing energy poverty.","Demand management of buildings; Demand response; District heating and district cooling; Load modulation; SWOT analysis; Thermal energy storage","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:87d4e6eb-5357-41df-afec-17d922e5ee63","http://resolver.tudelft.nl/uuid:87d4e6eb-5357-41df-afec-17d922e5ee63","From Potential to Practice: Intellectual Humility During Search on Debated Topics","Rieger, A. (TU Delft Web Information Systems); Bredius, Frank (Student TU Delft); Theune, Mariët (University of Twente); Pera, M.S. (TU Delft Web Information Systems)","","2024","An essential characteristic for unbiased and diligent information-seeking that can enable informed opinion formation and decision-making is intellectual humility (IH), the awareness of the limitations of one's knowledge and opinions. While researchers have recognized the potential to boost IH in individuals, the effect of such interventions on their search behavior, along with the broader significance of IH in the context of web search on debated topics remains unexplored. In this paper, we present the results of a preregistered user study (N = 299) that we conducted to (1) test the effect of three interventions that boost self-reported IH on opinionated individuals' search behavior and (2) explore the role of IH in the search process of opinionated individuals more broadly. IH-boosting interventions did not affect search behavior; we attribute this to the high familiarity of the search environment, prompting searchers to default to their usual search behavior. Still, explorations of the role of IH in the search process indicate that IH and IH-related search intentions should be considered as relevant factors in the pursuit of supporting unbiased and diligent search on debated topics. Based on our exploratory findings, we argue that future research should investigate interventions that are more directly integrated into the search process, as well as such that combine boosting IH with encouraging searchers to approach the search task in an IH-driven way and promoting transparency for appropriate reliance on the search system and ranking.","Boosting; Confirmation Bias; Debated Topics; Intellectual Humility; Web Search","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Web Information Systems","","",""
"uuid:18948d89-79a8-46af-8ee6-315bf5d4454a","http://resolver.tudelft.nl/uuid:18948d89-79a8-46af-8ee6-315bf5d4454a","Homing Objects: From Writing to Making","Sioli, A. (TU Delft Situated Architecture); Jennen, P.H.M. (TU Delft Architectural Technology); Matyiku, Anca (McGill University)","","2024","Can architects design with words? Can they move from words to models and then hands on making, bypassing the medium of drawing altogether? “Homing Objects” was a recent four-week workshop that tested this possibility. The workshop–part of the master level design course “The Space of Words” which explored different ways to address the above questions–was taught by three architects combining expertise in architectural theory, building technology and timber construction. “Homing Objects” asked architecture students to fabricate unprecedented domestic objects that were dreamed up and drawn out through language. “Homing” (borrowed from messenger pigeons) intends to turn “home” into a verb and an act, through a journey into memories and words that engender new possibilities of enacting and finding home, disrupting our preconceived notions about home and domesticity. We introduced the students to literary texts that describe everyday familiar objects. This introduction was meant to question and bring forward new possibilities of what a domestic object can be, as the literary texts offered unusual, uncanny, and unpredictable ways of seeing and relating to these objects. Following the close study of these texts, students were prompted to bring objects from their daily life to a shared common table. They “warmed up their inside voice” by writing short descriptions for three of these objects, in such a way that objects were hidden between the lines and were not named directly. This instruction pushed the students to see the familiar otherwise. Then they imagined possible combinations of these objects (or parts of these objects) that would create unprecedented new ones. Based on these imaginary combinations they proceeded with writing narratives that would describe, explain, and envision the new objects in the space of a home. Iterations of these narratives harvested, always in writing, design ideas for experiential qualities of these unique objects. Through writing and re-writing, many students moved further in envisioning objects that did not connect any more with the ones that were brought to the shared table. The students moved then to scaled models that gave the imagined objects a three-dimensional presence. The decision to exclude drawings from the process shifted the focus from what these invented objects might look like, to their sensorial qualities: what does it feel to hold an object in your hand, what sound does the use of an object create. Offering feedback on the models, always relating them with the narratives, led to more nuanced versions of these mock-ups and took us to the construction of the objects as finished and reproducible products. The students concluded the workshop composing a narrative that describes the use of their object from the perspective of a particular character. This narrative communicated functional aspects of the objects: elements that somebody could not easily understand without directly engaging with them. The end of “Homing Objects” meant the reinterpretation of what home might mean and the beginning of the studio’s final assignment: the building of full-scale domestic rooms, merging again through writing and language, that further questioned the notion of domesticity.","","en","conference paper","ACSA Press","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-01","","","Situated Architecture","","",""
"uuid:50eb4eb2-fbfc-4275-8398-3ba54d05c893","http://resolver.tudelft.nl/uuid:50eb4eb2-fbfc-4275-8398-3ba54d05c893","Firn on ice sheets","Amory, Charles (Université Grenoble Alpes); Buizert, Christo (Oregon State University); Buzzard, Sammie (Cardiff University; University of Northumbria); Case, Elizabeth (Columbia University); Clerx, Nicole (University of Fribourg); Culberg, Riley (Cornell University); Lhermitte, S.L.M. (TU Delft Mathematical Geodesy and Positioning; Katholieke Universiteit Leuven); de Roda Husman, S. (TU Delft Physical and Space Geodesy); Wouters, B. (TU Delft Physical and Space Geodesy)","","2024","Most of the Greenland and Antarctic ice sheets are covered with firn — the transitional material between snow and glacial ice. Firn is vital for understanding ice-sheet mass balance and hydrology, and palaeoclimate. In this Review, we synthesize knowledge of firn, including its formation, observation, modelling and relevance to ice sheets. The refreezing of meltwater in the pore space of firn currently prevents 50% of meltwater in Greenland from running off into the ocean and protects Antarctic ice shelves from catastrophic collapse. Continued atmospheric warming could inhibit future protection against mass loss. For example, warming in Greenland has already contributed to a 5% reduction in firn pore space since 1980. All projections of future firn change suggest that surface meltwater will have an increasing impact on firn, with melt occurring tens to hundreds of kilometres further inland in Greenland, and more extensively on Antarctic ice shelves. Although progress in observation and modelling techniques has led to a well-established understanding of firn, the large uncertainties associated with meltwater percolation processes (refreezing, ice-layer formation and storage) must be reduced further. A tighter integration of modelling components (firn, atmosphere and ice-sheet models) will also be needed to better simulate ice-sheet responses to anthropogenic warming and to quantify future sea-level rise.","","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-23","","","Mathematical Geodesy and Positioning","","",""
"uuid:fac2470e-9dd9-409f-bee0-31085beced91","http://resolver.tudelft.nl/uuid:fac2470e-9dd9-409f-bee0-31085beced91","Stochastic Navier–Stokes Equations for Turbulent Flows in Critical Spaces","Agresti, A. (TU Delft Analysis; Technische Universität Kaiserslautern); Veraar, M.C. (TU Delft Analysis)","","2024","In this paper we study the stochastic Navier–Stokes equations on the d-dimensional torus with transport noise, which arise in the study of turbulent flows. Under very weak smoothness assumptions on the data we prove local well-posedness in the critical case Bq,pd/q-1 for q∈[2,2d) and p large enough. Moreover, we obtain new regularization results for solutions, and new blow-up criteria which can be seen as a stochastic version of the Serrin blow-up criteria. The latter is used to prove global well-posedness with high probability for small initial data in critical spaces in any dimensions d⩾2. Moreover, for d=2, we obtain new global well-posedness results and regularization phenomena which unify and extend several earlier results.","","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:b5eb0b98-2552-4035-adcc-82643630b7c5","http://resolver.tudelft.nl/uuid:b5eb0b98-2552-4035-adcc-82643630b7c5","Spatial relationships in the urothelial and head and neck tumor microenvironment predict response to combination immune checkpoint inhibitors","Gil Jimenez, A. (Netherlands Cancer Institute; Oncode Institute); van Dijk, Nick (Netherlands Cancer Institute); Vos, Joris L. (Netherlands Cancer Institute); Lubeck, Yoni (Netherlands Cancer Institute); van Montfoort, Maurits L. (Netherlands Cancer Institute); Peters, Dennis (Netherlands Cancer Institute); Hooijberg, Erik (Netherlands Cancer Institute); Broeks, Annegien (Netherlands Cancer Institute); Wessels, L.F.A. (TU Delft Pattern Recognition and Bioinformatics; Netherlands Cancer Institute; Oncode Institute)","","2024","Immune checkpoint inhibitors (ICI) can achieve remarkable responses in urothelial cancer (UC), which may depend on tumor microenvironment (TME) characteristics. However, the relationship between the TME, usually characterized by immune cell density, and response to ICI is unclear. Here, we quantify the TME immune cell densities and spatial relationships (SRs) of 24 baseline UC samples, obtained before pre-operative combination ICI treatment, using multiplex immunofluorescence. We describe SRs by approximating the first nearest-neighbor distance distribution with a Weibull distribution and evaluate the association between TME metrics and ipilimumab+nivolumab response. Immune cell density does not discriminate between response groups. However, the Weibull SR metrics of CD8+ T cells or macrophages to their closest cancer cell positively associate with response. CD8+ T cells close to B cells are characteristic of non-response. We validate our SR response associations in a combination ICI cohort of head and neck tumors. Our data confirm that SRs, in contrast to density metrics, are strong biomarkers of response to pre-operative combination ICIs.","","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:a5f0fcf1-8233-4a09-a28b-90efe7a58425","http://resolver.tudelft.nl/uuid:a5f0fcf1-8233-4a09-a28b-90efe7a58425","Single-Component Electroactive Polymer Architectures for Non-Enzymatic Glucose Sensing","Kousseff, Christina J. (Queen Mary University of London); Wustoni, Shofarul (King Abdullah University of Science and Technology); Silva, Raphaela K.S. (King Abdullah University of Science and Technology); Lifer, Ariel (Technion); Savva, A. (TU Delft Bio-Electronics); Frey, Gitti L. (Technion); Inal, Sahika (King Abdullah University of Science and Technology); Nielsen, Christian B. (Queen Mary University of London)","","2024","Organic mixed ionic-electronic conductors (OMIECs) have emerged as promising materials for biological sensing, owing to their electrochemical activity, stability in an aqueous environment, and biocompatibility. Yet, OMIEC-based sensors rely predominantly on the use of composite matrices to enable stimuli-responsive functionality, which can exhibit issues with intercomponent interfacing. In this study, an approach is presented for non-enzymatic glucose detection by harnessing a newly synthesized functionalized monomer, EDOT-PBA. This monomer integrates electrically conducting and receptor moieties within a single organic component, obviating the need for complex composite preparation. By engineering the conditions for electrodeposition, two distinct polymer film architectures are developed: pristine PEDOT-PBA and molecularly imprinted PEDOT-PBA. Both architectures demonstrated proficient glucose binding and signal transduction capabilities. Notably, the molecularly imprinted polymer (MIP) architecture demonstrated faster stabilization upon glucose uptake while it also enabled a lower limit of detection, lower standard deviation, and a broader linear range in the sensor output signal compared to its non-imprinted counterpart. This material design not only provides a robust and efficient platform for glucose detection but also offers a blueprint for developing selective sensors for a diverse array of target molecules, by tuning the receptor units correspondingly.","electropolymerization; glucose sensor; organic bioelectronics; organic electrochemical transistors; PEDOT","en","journal article","","","","","","","","","","","Bio-Electronics","","",""
"uuid:08a20f34-0cbb-46f8-91cc-fc97481b68b8","http://resolver.tudelft.nl/uuid:08a20f34-0cbb-46f8-91cc-fc97481b68b8","Transition from time-variant to static networks: Timescale separation in N -intertwined mean-field approximation of susceptible-infectious-susceptible epidemics","Persoons, R.D.L. (TU Delft Network Architectures and Services); Sensi, M. (TU Delft Network Architectures and Services; University Côte d'Azur); Prasse, B. (TU Delft Network Architectures and Services; Politecnico di Torino); Van Mieghem, P.F.A. (TU Delft Network Architectures and Services; European Centre for Disease Prevention and Control)","","2024","We extend the N-intertwined mean-field approximation (NIMFA) for the susceptible-infectious-susceptible (SIS) epidemiological process to time-varying networks. Processes on time-varying networks are often analyzed under the assumption that the process and network evolution happen on different timescales. This approximation is called timescale separation. We investigate timescale separation between disease spreading and topology updates of the network. We introduce the transition times T(r) and T¯(r) as the boundaries between the intermediate regime and the annealed (fast changing network) and quenched (static network) regimes, respectively, for a fixed accuracy tolerance r. By analyzing the convergence of static NIMFA processes, we analytically derive upper and lower bounds for T¯(r). Our results provide insights and bounds on the time of convergence to the steady state of the static NIMFA SIS process. We show that, under our assumptions, the upper-transition time T¯(r) is almost entirely determined by the basic reproduction number R0 of the network. The value of the upper-transition time T¯(r) around the epidemic threshold is large, which agrees with the current understanding that some real-world epidemics cannot be approximated with the aforementioned timescale separation.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-23","","","Network Architectures and Services","","",""
"uuid:9d1a409c-094f-4588-87bd-40152407393d","http://resolver.tudelft.nl/uuid:9d1a409c-094f-4588-87bd-40152407393d","A high aspect ratio surface micromachined accelerometer based on a SiC-CNT composite material","Mo, J. (TU Delft Electronic Components, Technology and Materials); Shankar, S. (TU Delft EKL-Users); Pezone, R. (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Vollebregt, S. (TU Delft Electronic Components, Technology and Materials)","","2024","Silicon carbide (SiC) is recognized as an excellent material for microelectromechanical systems (MEMS), especially those operating in challenging environments, such as high temperature, high radiation, and corrosive environments. However, SiC bulk micromachining is still a challenge, which hinders the development of complex SiC MEMS. To address this problem, we present the use of a carbon nanotube (CNT) array coated with amorphous SiC (a-SiC) as an alternative composite material to enable high aspect ratio (HAR) surface micromachining. By using a prepatterned catalyst layer, a HAR CNT array can be grown as a structural template and then densified by uniformly filling the CNT bundle with LPCVD a-SiC. The electrical properties of the resulting SiC-CNT composite were characterized, and the results indicated that the electrical resistivity was dominated by the CNTs. To demonstrate the use of this composite in MEMS applications, a capacitive accelerometer was designed, fabricated, and measured. The fabrication results showed that the composite is fully compatible with the manufacturing of surface micromachining devices. The Young’s modulus of the composite was extracted from the measured spring constant, and the results show a great improvement in the mechanical properties of the CNTs after coating with a-SiC. The accelerometer was electrically characterized, and its functionality was confirmed using a mechanical shaker. (Figure presented.)","","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:36b9ec2e-8724-48f8-845f-5453cae57982","http://resolver.tudelft.nl/uuid:36b9ec2e-8724-48f8-845f-5453cae57982","Effect of air-loading on the performance limits of graphene microphones","Pezone, R. (TU Delft Electronic Components, Technology and Materials); Baglioni, G. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); van Ruiten, C. (Student TU Delft); Anzinger, S. (Infineon Technologies AG); Wasisto, H. S. (Infineon Technologies AG); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Steeneken, P.G. (TU Delft Dynamics of Micro and Nano Systems; TU Delft QN/Steeneken Lab; Kavli institute of nanoscience Delft); Vollebregt, S. (TU Delft Electronic Components, Technology and Materials)","","2024","As a consequence of their high strength, small thickness, and high flexibility, ultrathin graphene membranes show great potential for pressure and sound sensing applications. This study investigates the performance of multi-layer graphene membranes for microphone applications in the presence of air-loading. Since microphones need a flatband response over the full audible bandwidth, they require a sufficiently high mechanical resonance frequency. Reducing membrane thickness facilitates meeting this bandwidth requirement, and therefore, also allows increasing compliance and sensitivity of the membranes. However, at atmospheric pressure, air-loading effects can increase the effective mass, and thus, reduce the bandwidth of graphene and other 2D material-based microphones. To assess the severity of this performance-limiting effect, we characterize the acoustic response of multi-layer graphene membranes with a thickness of 8 nm in the pressure range from 30 to 1000 mbar, in air and helium environments. A bandwidth reduction by a factor ∼ 2.8 × for membranes with a diameter of 500 μm is observed. These measurements show that air-loading effects, which are usually negligible in conventional microphones, can lead to a substantial bandwidth reduction in ultrathin graphene microphones. With analytical and finite element models, we further analyze the performance limits of graphene microphones in the presence of air-loading effects.","","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:3e32ae56-d122-4154-a934-6e4ddf412e0f","http://resolver.tudelft.nl/uuid:3e32ae56-d122-4154-a934-6e4ddf412e0f","Amplidiff: an optimized amplicon sequencing approach to estimating lineage abundances in viral metagenomes","van Bemmelen, J. (TU Delft Pattern Recognition and Bioinformatics); Smyth, Davida S. (Texas A&M University-San Antonio); Baaijens, J.A. (TU Delft Pattern Recognition and Bioinformatics; Harvard Medical School)","","2024","Background: Metagenomic profiling algorithms commonly rely on genomic differences between lineages, strains, or species to infer the relative abundances of sequences present in a sample. This observation plays an important role in the analysis of diverse microbial communities, where targeted sequencing of 16S and 18S rRNA, both well-known hypervariable genomic regions, have led to insights into microbial diversity and the discovery of novel organisms. However, the variable nature of discriminatory regions can also act as a double-edged sword, as the sought-after variability can make it difficult to design primers for their amplification through PCR. Moreover, the most variable regions are not necessarily the most informative regions for the purpose of differentiation; one should focus on regions that maximize the number of lineages that can be distinguished. Results: Here we present AmpliDiff, a computational tool that simultaneously finds highly discriminatory genomic regions in viral genomes of a single species, as well as primers allowing for the amplification of these regions. We show that regions and primers found by AmpliDiff can be used to accurately estimate relative abundances of SARS-CoV-2 lineages, for example in wastewater sequencing data. We obtain errors that are comparable with using whole genome information to estimate relative abundances. Furthermore, our results show that AmpliDiff is robust against incomplete input data and that primers designed by AmpliDiff also bind to genomes sampled months after the primers were selected. Conclusions: With AmpliDiff we provide an effective, cost-efficient alternative to whole genome sequencing for estimating lineage abundances in viral metagenomes.","Abundance estimation; Amplicon sequencing; Primer design; Set cover problem","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:7909090a-0ea9-414d-9cae-1ed72a7f9eb7","http://resolver.tudelft.nl/uuid:7909090a-0ea9-414d-9cae-1ed72a7f9eb7","ROBUST: 221 bugs in the Robot Operating System","Timperley, Christopher S. (Carnegie Mellon University); van der Hoorn, G.A. (TU Delft Robot Dynamics); Santos, André (VORTEX CoLab); Deshpande, Harshavardhan (Fraunhofer Institute for Manufacturing Engineering and Automation); Wąsowski, Andrzej (University of Copenhagen)","","2024","As robotic systems such as autonomous cars and delivery drones assume greater roles and responsibilities within society, the likelihood and impact of catastrophic software failure within those systems is increased. To aid researchers in the development of new methods to measure and assure the safety and quality of robotics software, we systematically curated a dataset of 221 bugs across 7 popular and diverse software systems implemented via the Robot Operating System (ROS). We produce historically accurate recreations of each of the 221 defective software versions in the form of Docker images, and use a grounded theory approach to examine and categorize their corresponding faults, failures, and fixes. Finally, we reflect on the implications of our findings and outline future research directions for the community.","BugZoo; Dataset; Robot Operating System; Robotics; ROS; Software bugs","en","journal article","","","","","","","","","","","Robot Dynamics","","",""
"uuid:99d09639-19ff-4bd8-b113-3dff0119008b","http://resolver.tudelft.nl/uuid:99d09639-19ff-4bd8-b113-3dff0119008b","Reliable and Energy-efficient Diabetic Retinopathy Screening using Memristor-based Neural Networks","Diware, S.S. (TU Delft Computer Engineering); Chilakala, Koteswararao (Capgemini Engineering); Joshi, Rajiv V. (IBM Thomas J. Watson Research Centre); Hamdioui, S. (TU Delft Computer Engineering); Bishnoi, R.K. (TU Delft Computer Engineering)","","2024","Diabetic retinopathy (DR) is a leading cause of permanent vision loss worldwide. It refers to irreversible retinal damage caused due to elevated glucose levels and blood pressure. Regular screening for DR can facilitate its early detection and timely treatment. Neural network-based DR classifiers can be leveraged to achieve such screening in a convenient and automated manner. However, these classifiers suffer from reliability issue where they exhibit strong performance during development but degraded performance after deployment. Moreover, they do not provide supplementary information about the prediction outcome, which severely limits their widespread adoption. Furthermore, energy-efficient deployment of these classifiers on edge devices remains unaddressed, which is crucial to enhance their global accessibility. In this paper, we present a reliable and energy-efficient hardware for DR detection, suitable for deployment on edge devices. We first develop a DR classification model using custom training data that incorporates diverse image quality and image sources along with improved class balance. This enables our model to effectively handle both on-field variations in retinal images and minority DR classes, enhancing its post-deployment reliability. We then propose a pseudo-binary classification scheme to further improve the model performance and provide supplementary information about the model prediction. Additionally, we present an energy-efficient hardware design for our model using memristor-based computation-in-memory, to facilitate its deployment on edge devices. Our proposed approach achieves reliable DR classification with three orders of magnitude reduction in energy consumption over state-of-the-art hardware platforms.","computation-in-memory; Data models; Diabetic retinopathy; edge computing; Energy efficiency; Hardware; memristor; Memristors; Neural networks; neural networks; Reliability; reliability; resistive random access memory; Retina; RRAM","en","journal article","","","","","","","","","","","Computer Engineering","","",""
"uuid:c86b11d0-5c68-4301-a916-d35a7e302444","http://resolver.tudelft.nl/uuid:c86b11d0-5c68-4301-a916-d35a7e302444","Direct observation of a crescent-shape chromosome in expanded Bacillus subtilis cells","Tišma, M. (TU Delft BN/Cees Dekker Lab); Bock, Florian Patrick (University of Lausanne); Kerssemakers, J.W.J. (TU Delft BN/Cees Dekker Lab); Antar, Hammam (University of Lausanne); Japaridze, A. (TU Delft Dynamics of Micro and Nano Systems); Gruber, Stephan (University of Lausanne); Dekker, C. (TU Delft BN/Cees Dekker Lab)","","2024","Bacterial chromosomes are folded into tightly regulated three-dimensional structures to ensure proper transcription, replication, and segregation of the genetic information. Direct visualization of chromosomal shape within bacterial cells is hampered by cell-wall confinement and the optical diffraction limit. Here, we combine cell-shape manipulation strategies, high-resolution fluorescence microscopy techniques, and genetic engineering to visualize the shape of unconfined bacterial chromosome in real-time in live Bacillus subtilis cells that are expanded in volume. We show that the chromosomes predominantly exhibit crescent shapes with a non-uniform DNA density that is increased near the origin of replication (oriC). Additionally, we localized ParB and BsSMC proteins – the key drivers of chromosomal organization – along the contour of the crescent chromosome, showing the highest density near oriC. Opening of the BsSMC ring complex disrupted the crescent chromosome shape and instead yielded a torus shape. These findings help to understand the threedimensional organization of the chromosome and the main protein complexes that underlie its structure.","","en","journal article","","","","","","","","","","","BN/Cees Dekker Lab","","",""
"uuid:daac5646-ba52-496e-8111-edde537e3b0b","http://resolver.tudelft.nl/uuid:daac5646-ba52-496e-8111-edde537e3b0b","Influence of marker-selection method in radiostereometric analysis of total knee arthroplasty on tibial baseplate migration patterns: a secondary analysis of a randomized controlled trial with 5-year follow-up","van der Lelij, T.J.N. (Leiden University Medical Center); Koster, Lennard A. (Leiden University Medical Center); Marang-van de Mheen, P.J. (TU Delft Safety and Security Science; Leiden University Medical Center); Toksvig-Larsen, Sören (Hässleholm Hospital; Lund University); Nelissen, R.G.H.H. (Leiden University Medical Center); Kaptein, B.L. (Leiden University Medical Center)","","2024","Background and purpose — Different marker-selection methods are applied to represent implant and tibial seg-ments in radiostereometric analysis (RSA) studies of total knee arthroplasty (TKA). Either a consistent set of markers throughout subsequent RSA examinations (“consistent-marker method”) is used or all available markers at each follow-up (“all-marker method”). The aim of this secondary analysis was to compare marker-selection methods on individual and group level TKA migration results. Methods — Data from a randomized RSA study with 72 patients was included. Tibial baseplate migration was evalu-ated at 3 months, 1, 2, and 5 years postoperatively with both marker-selection methods. Additionally, migration was calculated using 5 fictive points, either plotted based on the consistent set of markers or all available markers. Results — Migration could be calculated with both marker-selection methods for 248 examinations. The same prosthesis and bone markers (n = 136), different prosthesis markers (n = 71), different bone markers (n = 21), or different prosthesis and bone markers (n = 20) were used. The mean difference in maximum total point motion (MTPM) between all examinations was 0.02 mm, 95% confidence interval –0.26 to 0.31 mm. 5 implants were classified as continuously migrating with the consistent-marker method versus 6 implants (same 5 plus one additional implant) with the all-marker method. Using fictive points, fewer implants were classified as continuously migrating in both marker-selection methods. Differences between TKA groups in mean MTPM were comparable with both marker-selection methods, also when fictive points were used. Conclusion — Estimated group differences in mean MTPM were similar between marker-selection methods, but individual migration results differed. The latter has implications when classifying implants for estimated risk of future loosening.","Arthroplasty; Knee; Loosening; Migration; Radiostereometric analysis","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:2d922fc6-db78-4c04-9463-904714352cae","http://resolver.tudelft.nl/uuid:2d922fc6-db78-4c04-9463-904714352cae","Amplifying weak signals: A method-building approach for inclusive climate resilience strategy making","Champlin, C.J. (TU Delft Design Conceptualization and Communication); Eapen, Ann (Student TU Delft); Vitkutė, R. (Student TU Delft); Groot, Janne (Student TU Delft); Forgaci, C. (TU Delft Urban Design)","","2024","Socio-ecological inclusion and the impacts of climate change on the built environment are two shared concerns central to the design and planning of the just transition in cities. The just transition leans heavily on inclusive convergence processes that are grounded in knowledge integration and transdisciplinary practice. However, there is a paucity of effective methods for the inclusion of so-called weak signals from actors situated at the periphery of these convergence processes. Building on the concept of structured flexibility, we introduce a building-blocks approach as a modular architecture for constructing methods for distributed engagement and knowledge integration beyond conventional small-group settings. By engaging in research through design, the Amplifying Weak Signals approach was prototyped with students in the context of dealing with heatwaves in The Hague and tested with expert users from the region who facilitate resilience strategy-making processes. Out of 900 possible building block combinations, 18 methods were created during prototyping. The resulting heatwave strategies that were drafted based on the collected peripheral knowledge showed the integration of new socio-ecological issues rather than a drastic departure from the baseline resilience strategy of the city. We discuss the research findings and their use in the production of guidelines for the construction of methods to integrate peripheral knowledge in convergence processes. Ongoing work to develop the guidelines in the form of an open-access, interactive repository of knowledge elicitation methods for urban resilience spatial planning will also be described. Recommendations for scaling the approach are provided.","building blocks; co-design; research through design; strategy making; structured flexibility; toolkitting; transdisciplinarity; urban resilience","en","journal article","","","","","","","","","","","Design Conceptualization and Communication","","",""
"uuid:e044c245-e161-42a9-aa81-6176999f872a","http://resolver.tudelft.nl/uuid:e044c245-e161-42a9-aa81-6176999f872a","Assessment of cyclic deformation behaviour of wire arc additively manufactured carbon steel","Mendez-Morales, Mariela (Universidade de Coimbra); Branco, Ricardo (Universidade de Coimbra); Tankova, T. (TU Delft Steel & Composite Structures); Rebelo, Carlos (Universidade de Coimbra)","","2024","Wire Arc Additive Manufacturing (WAAM) has gained popularity due to its speed and cost-effectiveness. However, the current knowledge on the cyclic deformation behaviour of WAAM materials is limited. To address this issue, this study investigates the cyclic deformation behaviour of WAAM ER70S-6 carbon steel. Coupons were extracted from printed walls with horizontal and vertical orientations and from surface and interior locations. Low-cycle fatigue tests were performed under fully reversed strain-controlled conditions, spanning strain amplitudes from 0.20 % to 1.50 %. Regardless of the group, the material exhibited cyclic hardening for strain amplitudes above 0.60 % and cyclic softening for smaller strain amplitudes. Significant non-Masing hysteretic behaviour was also observed. Cyclic stress–strain curves and fatigue-life relationships written in terms of stress, strain and energy-based parameters were derived for all groups. Fatigue life was not significantly influenced by printing orientation or location across thickness. However, horizontal orientation resulted in a slightly superior fatigue response. A statistical analysis revealed no significant difference in the accuracy of fatigue-life relationships between the groups. Finally, a comparative study between WAAM materials and conventional steels showed promising results. Yet, conventional steels outperform WAAM carbon steel, at least doubling the fatigue life for the same value of the damage parameter.","Carbon steel; Cyclic deformation behaviour; ER70S-6; Low-cycle fatigue; Wire-arc additive manufacturing","en","journal article","","","","","","","","","","","Steel & Composite Structures","","",""
"uuid:896d1388-10e5-4142-980c-e8c9c77ddfff","http://resolver.tudelft.nl/uuid:896d1388-10e5-4142-980c-e8c9c77ddfff","Model-based approach for the automatic inclusion of production considerations in the conceptual design of aircraft structures","Bruggeman, A.M.R.M. (TU Delft Flight Performance and Propulsion); Bansal, D. (TU Delft Flight Performance and Propulsion); la Rocca, G. (TU Delft Flight Performance and Propulsion); van der Laan, T (Fokker Aerostructures); van den Berg, T. (Fokker/GKN Aerospace)","","2024","Including production considerations in the early design stages of aircraft structures is challenging. Production information is mostly known by experts and rarely formally documented such that it can be effectively used during the design process. Producibility is mostly considered after completing the design, resulting in increased cost and development time due to the late discovery of production issues. This paper presents a new model, called the Manufacturing Information Model (MIM), which supports the automatic inclusion of production considerations into the design process. The MIM provides a single source of truth and a generic structure to capture and organize production-related information in a product system. Furthermore, it provides compatibility analyses to automatically warn for or exclude infeasible designs. Analysis tools use the information stored within the MIM to calculate the mass, costs, and production rate of the product. To show the functionalities of the MIM, it has been applied to the conceptual design of a wing box at a Tier 1 company. This use case shows how the MIM supports trade-off decisions, as it allows for the identification of trends and the ranking of different manufacturing concepts. Overall, the MIM provides a structured and formal approach to include production information in the conceptual design, improving the decision-making process.","","en","journal article","","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:f051beba-b13f-42f9-a8d2-4c539fd36039","http://resolver.tudelft.nl/uuid:f051beba-b13f-42f9-a8d2-4c539fd36039","Digital geoTwin: A CityGML-Based Data Model for the Virtual Replica of the City of Vienna","Lehner, Hubert (Vienna City Administration); Kordasch, Sara Lena (Vienna City Administration); Glatz, Charlotte (Vienna City Administration); Agugiaro, G. (TU Delft Urban Data Science)","Kolbe, Thomas H. (editor); Donaubauer, Andreas (editor); Beil, Christof (editor)","2024","This paper presents a CityGML-based data model developed for the semantic 3D city model of Vienna, Austria. The data model consists in a profile of the CityGML 2.0 standard and has been extended by means of an Application Domain Extension (ADE) developed by the Department for Surveying and Mapping of the City of Vienna in order to comply with the current and future needs of the municipality. The definition and adoption of such data model are a fundamental part of Vienna’s “Digital geoTwin” project. The core of the strategy is to process the 3D measurement data of the surveying and mapping department from existing as well as new measurement methods directly into a Digital geoTwin—a virtual, semantic 3D replica of all objects in the city—and to derive other geodata products (city map, elevation models, etc.) from this 3D model. Furthermore, the Digital geoTwin should serve as a geometric and semantic basis for a digital twin of the City of Vienna. In order to define the data model for the Digital geoTwin, 3D modelling of all city objects has been carried out in a test area of the city, followed by a mapping of the objects to the CityGML data model. In an iterative development process, conceptual gaps have been identified, analysed and eventually formalized into a UML-based Application Domain Extension. Additionally, the free and open-source CityGML 3D City Database (3DCityDB) has been used for storage after being extended accordingly, and FME workbenches have been created to transform and import the original source data into the 3DCityDB and therefore test the suitability of the developed data model.","Digital geoTwin; Urban digital twin; Data modelling; 3D city model; CityGML ADE","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-21","","","Urban Data Science","","",""
"uuid:f079cc69-8f14-4f2f-a7e5-28a57c5251a7","http://resolver.tudelft.nl/uuid:f079cc69-8f14-4f2f-a7e5-28a57c5251a7","Comparison of Cloud-to-Cloud Distance Calculation Methods: Is the Most Complex Always the Most Suitable?","Diaz, Vitali (TU Delft Digital Technologies); van Oosterom, P.J.M. (TU Delft Digital Technologies); Meijers, B.M. (TU Delft Digital Technologies); Verbree, E. (TU Delft Digital Technologies); Ahmed, N. (Netherlands eScience Center); Van Lankveld, T. (Netherlands eScience Center)","Kolbe, Thomas H. (editor); Donaubauer, Andreas (editor); Beil, Christof (editor)","2024","Cloud-to-cloud (C2C) distance calculations are frequently performed as an initial stage in change detection and spatiotemporal analysis with point clouds. There are various methods for calculating C2C distance, also called inter-point distance, which refers to the distance between two corresponding point clouds captured at different epochs. These methods can be classified from simple to complex, with more steps and calculations required for the latter. Generally, it is assumed that a more complex method will result in a more precise calculation of inter-point distance, but this assumption is rarely evaluated. This paper compares eight commonly used methods for calculating the inter-point distance. The results indicate that the accuracy of distance calculations depends on the chosen method and a characteristic related to the point density, the intra-point distance, which refers to the distance between points within the same point cloud. The results are helpful for applications that analyze spatiotemporal point clouds for change detection. The findings will be helpful in future applications, including analyzing spatiotemporal point clouds for change detection.","Cloud-to-cloud distance calculations; Change detection; Spatiotemporal analysis","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-21","","","Digital Technologies","","",""
"uuid:a8c4a992-5047-49e8-b084-ab9fa91cc28c","http://resolver.tudelft.nl/uuid:a8c4a992-5047-49e8-b084-ab9fa91cc28c","Shadowing Calculation on Urban Areas from Semantic 3D City Models","Xu, Longxiang (Student TU Delft); León Sánchez, C.A. (TU Delft Urban Data Science); Agugiaro, G. (TU Delft Urban Data Science); Stoter, J.E. (TU Delft Urban Data Science)","Kolbe, Thomas H. (editor); Donaubauer, Andreas (editor); Beil, Christof (editor)","2024","Nowadays, our society is in the transit to adopt more sustainable energy sources to reduce our impact on the environment; one alternative is solar energy. However, this is highly affected by the surroundings, which might cause shadowing effects. In this paper, we present our method to perform shadowing calculations in urban areas using semantic 3D city models, which is split into five sections: Point Grid Generation, Sun-Ray Generation, Nightside Filtering, Bounding Volume Hierarchy and the intersection between the sun rays and the BVH to identify which locations are shadowed at a given moment (epoch). Our tests are performed in Rotterdam’s city center, a dense urban area in The Netherlands. Our initial results indicate that the computational time per 100 k grid points fluctuates within 0.2–0.7s.","Solar potential; 3DCM; Shadows analysis; Raytracing","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-21","","","Urban Data Science","","",""
"uuid:93091ce0-2aa5-4b71-854e-43cb9ed37e07","http://resolver.tudelft.nl/uuid:93091ce0-2aa5-4b71-854e-43cb9ed37e07","Unsupervised Roofline Extraction from True Orthophotos for LoD2 Building Model Reconstruction","Gao, W. (TU Delft Urban Data Science); Peters, R.Y. (3DGI); Stoter, J.E. (TU Delft Urban Data Science)","Kolbe, Thomas H. (editor); Donaubauer, Andreas (editor); Beil, Christof (editor)","2024","This paper discusses the reconstruction of LoD2 building models from 2D and 3D data for large-scale urban environments. Traditional methods involve the use of LiDAR point clouds, but due to high costs and long intervals associated with acquiring such data for rapidly developing areas, researchers have started exploring the use of point clouds generated from (oblique) aerial images. However, using such point clouds for traditional plane detection-based methods can result in significant errors and introduce noise into the reconstructed building models. To address this, this paper presents a method for extracting rooflines from true orthophotos using line detection for the reconstruction of building models at the LoD2 level. The approach is able to extract relatively complete rooflines without the need for pre-labeled training data or pre-trained models. These lines can directly be used in the LoD2 building model reconstruction process. The method is superior to existing plane detection-based methods and state-of-the-art deep learning methods in terms of the accuracy and completeness of the reconstructed building. Our source code is available at https://github.com/tudelft3d/Roofline-extraction-from-orthophotos.","Building rooflines extraction; 3D building models; True orthophotos; Raytracing","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-21","","","Urban Data Science","","",""
"uuid:f3095acb-a2f4-4b87-bc88-328c359b34c3","http://resolver.tudelft.nl/uuid:f3095acb-a2f4-4b87-bc88-328c359b34c3","Better decisions with less cognitive load: The Parsimonious BWM","Corrente, Salvatore (University of Catania); Greco, Salvatore (University of Catania); Rezaei, J. (TU Delft Transport and Logistics)","","2024","Despite its recent introduction in literature, the Best–Worst Method (BWM) is among the most well-known and applied methods in Multicriteria Decision-Making. The method can be used to elicit the relative importance (weight) of the criteria as well as to get the priorities of the alternatives on the criteria at hand. In this paper, we will present an extension of the method, namely, the parsimonious Best–Worst-Method (P-BWM) permitting to apply the BWM to get the priorities of the alternatives in case they are in a large number. At first, the Decision-Maker (DM) is asked to give a rating to the alternatives under consideration; after, the classical BWM is applied to a set of reference alternatives to get their priorities used to compute, then, the priorities of all the alternatives under consideration. We propose also a procedure to select reference alternatives, possibly in cooperation with the DM, providing a well-distributed coverage of the rating range. The new proposal requires the DM a fewer number of pairwise comparisons than the original BWM. Another contribution of the paper is related to the comparison between BWM, P-BWM, the Analytic Hierarchy Process (AHP), and the parsimonious AHP in terms of the amount of preference information provided by the DM in each method to apply it. In addition to the standard approach, we propose one alternative way of inferring the priority vectors in BWM and P-BWM based on the barycenter of the space of alternatives priorities compatible with the preferences given by the DM. Finally, an experiment with university students has been conducted to test the new proposal. Results of the experiments show that P-BWM performs better than BWM in terms of capability to represent the DM's preferences and the difference between the results of the two methods is significant from the statistical point of view. The new proposal will permit to use the potentialities of the BWM to get the alternatives’ priorities in real-world decision-making problems where a large number of alternatives must be taken into account.","Alternatives’ priorities; Best–Worst Method; Parsimonious elicitation","en","journal article","","","","","","","","","","","Transport and Logistics","","",""
"uuid:063ae36f-f9d1-442b-abbc-2a8f60452c34","http://resolver.tudelft.nl/uuid:063ae36f-f9d1-442b-abbc-2a8f60452c34","Wriggling in the crowd: An inquiry into the interactions between electric bikes and pedestrians in a shared space","Kazemzadeh, Khashayar (University of Cambridge); Afghari, A.P. (TU Delft Safety and Security Science)","","2024","Shared spaces for active mobility aim to offer safe and comfortable mobility for vulnerable road users by separating them from motorised vehicles. However, the distinct navigation characteristics of these users may increase the complexity of their interactions. The emergence of e-bikes which are faster and heavier than regular bikes has further increased this complexity. This study aims to shed light on the interdependency of e-bikes and pedestrians behaviours in shared spaces, and investigate how they influence each other's navigation. Through a controlled experiment in Lund, Sweden, data were collected on a total of 1520 trajectories of e-bike and pedestrians, their demographics and cycling experience. A simultaneous equation model was used to quantify the interactions between the participants. Results demonstrate significant correlations among variables, highlighting the model's capacity to effectively capturing the hypothesized interdependencies. The findings can inform the development of level-of-service indices and surrogate safety measures for shared spaces.","Cyclists; Electric bikes; Interaction; Level of service; Pedestrians; Shared spaces; Vulnerable road users","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:221111fe-f9ea-48d6-bd58-d4a15b409079","http://resolver.tudelft.nl/uuid:221111fe-f9ea-48d6-bd58-d4a15b409079","Data-driven model to predict burst pressure in the presence of interacting corrosion pits","Yarveisy, R. (TU Delft Safety and Security Science; Memorial University of Newfoundland); Khan, Faisal (Texas A&M University); Abbassi, Rouzbeh (Macquarie University)","","2024","This paper presents a data-driven approach to predict the pipelines’ corrosion-induced Burst failure. In this approach, different aspects of pit growth progression and spatial distribution of pits are simulated. The proposed approach takes advantage of population characteristics to model these aspects of the degradation paths for each pipe section down to the size of single joints. The insights obtained from simulations are used to project the degradation of each pipe section. Understanding corrosion behavior and field data are used to model the corrosion-related parameters such as corrosion pit dimensions, probability and time of initiation, and location. The failure is modeled using the probabilistic simulation considering degradation rate, interactions among pits, and material properties as stochastic variables. The proposed approach and included models are tested using multiple real-life inline inspection datasets. Validation of predicted properties shows prediction errors ranging from 3%–10% depending on the three remaining strength calculation approaches. This work aimed to serve as an important tool for risk-based maintenance prioritization, inspection interval assessment, and the fitness of service assessment of pipelines.","Extreme value analysis; Failure analysis; Inline inspection; Monte Carlo simulation; Pipeline failure analysis; Pitting corrosion","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:857c7f7e-c815-43e8-9bed-44b941daf8f6","http://resolver.tudelft.nl/uuid:857c7f7e-c815-43e8-9bed-44b941daf8f6","The Relationship Between Barriers to Physical Activity and Depressive Symptoms in Community-Dwelling Women","Figueroa, C.A. (TU Delft Information and Communication Technology; University of California); Aguilera, Adrian (University of California); Hoffmann, Thomas J. (University of California); Fukuoka, Yoshimi (University of California)","","2024","Background: Women are less physically active, report greater perceived barriers for exercise, and show higher levels of depressive symptoms. This contributes to high global disability. The relationship between perceived barriers for physical activity and depressive symptoms in women remains largely unexplored. The aims of this cross-sectional analysis were to examine the association between physical activity barriers and depressive symptoms, and identify types of barriers in physically inactive community-dwelling women. Methods: Three hundred eighteen physically inactive women aged 25–65 years completed the Barriers to Being Active Quiz (BBAQ) developed by the Centers for Disease Control and Prevention, and the Center for Epidemiological Studies Depression Scale at the baseline visit of the mobile phone-based physical activity education trial. The BBAQ consists of six subscales (lack of time, social influence, lack of energy, lack of willpower, fear of injury, lack of skill, and lack of resources). We used multivariate regression analyses, correcting for sociodemographics. Results: Higher physical activity barriers were associated with greater depressive symptoms scores (linear effect, estimate = 0.75, 95% confidence interval [CI]: 0.39–1.12, p < 0.001). This effect appeared to taper off for the higher barrier scores (quadratic effect, estimate: -0.02, 95% CI: -0.03 to -0.01, p = 0.002). Exploratory analyses indicated that these associations were most driven by the social influence (p = 0.027) and lack of energy subscales (p = 0.017). Conclusions: Higher depression scores were associated with higher physical activity barriers. Social influence and lack of energy were particularly important barriers. Addressing these barriers may improve the efficacy of physical activity interventions in women with higher depressive symptoms. Future research should assess this in a randomized controlled trial.","depressive symptoms; exercise; physical activity; preventive medicine; women’s health","en","journal article","","","","","","","","","","","Information and Communication Technology","","",""
"uuid:518836f0-7b9c-4b55-96d6-638de4a1f230","http://resolver.tudelft.nl/uuid:518836f0-7b9c-4b55-96d6-638de4a1f230","Consolidating backcasting: A design framework towards a users’ guide","Kishita, Yusuke (University of Tokyo); Höjer, Mattias (KTH Royal Institute of Technology); Quist, J.N. (TU Delft Energie and Industrie)","","2024","Backcasting has become a widely applied approach to address sustainability challenges when transformative changes are required. However, dispersed and contextualized knowledge of backcasting methodologies and practices needs to be systematized, codified, and synthesized to support researchers, commissioners, practitioners, and stakeholders in backcasting projects. In this paper, we address these issues by (i) concisely reviewing the evolution and current body of literature on backcasting and how this relates to other major types of futures and scenario studies and (ii) developing a design framework for researchers and practitioners that systematically covers all methodological choices with regard to key guiding questions to develop a backcasting methodology for a particular backcasting project. The developed design framework is based on four parts, characterized by the interrogatives when, which, how, and what, creating a comprehensive framework for describing a backcasting study.","Backcasting; Design framework; Foresight; Futures studies; Sustainability transitions","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:98f81e01-8824-40b0-bc23-aaa1b497394c","http://resolver.tudelft.nl/uuid:98f81e01-8824-40b0-bc23-aaa1b497394c","The role of health, safety and environmental perceptions on forming bus passengers’ loyalty – A case study of Vietnam","Tran-Thi, Anh Phuong (The University of Da Nang); Nguyen-Phuoc, Duy Quy (The University of Da Nang); Phan, Tho Cao (The University of Da Nang); Oviedo-Trespalacios, O. (TU Delft Safety and Security Science)","","2024","Introduction: Responsible businesses actively engage in climate action, health, and safety initiatives as part of their corporate strategy. The outcomes of such initiatives could play an essential role in forming customers' loyalty. However, very few studies have aimed at understanding the relationship among such factors in the public transport (PT) context. As such, this investigation explores the direct impact of perception of health benefits, environmental benefits and safety on passengers’ loyalty intentions towards a PT service. The mediating roles of image and perceived value on these links are also considered. Methods: Partial Least Square - Structural Equation Modeling (PLS-SEM) was utilised to assess the measurement and develop structural models. A multi-group analysis (MGA) was also deployed to test the significant group differences. For this investigation, a sample of 866 individuals was collected from two cities in Vietnam. Results: The results indicate that there were significant relationships between these constructs and the loyalty intention of passengers. The perception of health benefits and image were the main factors affecting passengers’ loyalty in both cities. In contrast, the perception of environmental benefits had the weakest effect on the loyalty intention towards bus services. Conclusions: The results from this study could support the development of interventions to increase PT ridership in low-income countries. Promotional efforts to boost PT ridership should focus on highlighting the health benefits of using PT for passengers and the community. PT operators were also recommended to convey societal and environmental contributions through logos, graphic design, mission statements, slogans, and media relations to improve the image of the bus services.","Environmental benefits; Health benefits; Image; Loyalty; Perceived value","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-01","","","Safety and Security Science","","",""
"uuid:11faa5d0-39d3-42bb-90f9-28a8bb9f2088","http://resolver.tudelft.nl/uuid:11faa5d0-39d3-42bb-90f9-28a8bb9f2088","Wall shear stress measurement using a zero-displacement floating-element balance","Aguiar Ferreira, Manuel (TU Delft Fluid Mechanics); Costa, P. (Lisbon Technical University); Ganapathisubramani, B. (University of Southampton)","","2024","The floating-element (FE) principle, introduced nearly a century ago, remains one of the most versatile direct wall shear stress measurement methods. Yet, its intrinsic sources of systematic error, associated with the flow-exposed gap, off-axis load sensitivity, and calibration, have thus far limited its widespread application. In combination with the lack of standard designs and testing procedures, measurement reliability still hinges heavily on individual judgement and expertise. This paper presents a framework to curb these limitations, whereby the design and operation of a FE balance are leveraged by an analytical model that attempts to capture the behaviour and predict the relative contribution of the systematic sources of error. The design is based on a parallel-shift linkage and a zero-displacement force-feedback system. The FE has a surface area of 200×200 mm, and measurement sensitivity is adjustable depending on the surface condition and the Reynolds number. It is thus suitable for application in a wide range of low-speed, boundary-layer wind tunnels, small or large scale. Measurements of the skin friction coefficient over a smooth wall show a remarkable agreement with oil-film interferometry, especially for Reθ>1.3×104. The discrepancy relative to the empirical Coles–Fernholz relation (κ=0.39 and C=4.352) is within 0.5%, and the level of uncertainty is below 1% for a confidence interval of 95%.","","en","journal article","","","","","","","","","","","Fluid Mechanics","","",""
"uuid:e34c80e7-1942-41b0-bad8-0b77144c63d7","http://resolver.tudelft.nl/uuid:e34c80e7-1942-41b0-bad8-0b77144c63d7","4D Neutron Imaging of Solute Transport and Fluid Flow in Sandstone Before and After Mineral Precipitation","Shafabakhsh, Paiman (Universitetet i Oslo); Cordonnier, Benoît (Universitetet i Oslo); Pluymakers, Anne (TU Delft Applied Geophysics and Petrophysics); Le Borgne, Tanguy (Universitetet i Oslo; Université de Rennes); Mathiesen, Joachim (Universitetet i Oslo; University of Copenhagen); Linga, Gaute (Universitetet i Oslo; Norwegian University of Science and Technology (NTNU)); Hu, Yi (Universitetet i Oslo); Kaestner, Anders (Paul Scherrer Institut); Renard, François (Universitetet i Oslo; Institut des Sciences de la Terre, Grenoble)","","2024","In many geological systems, the porosity of rock or soil may evolve during mineral precipitation, a process that controls fluid transport properties. Here, we investigate the use of 4D neutron imaging to image flow and transport in Bentheim sandstone core samples before and after in-situ calcium carbonate precipitation. First, we demonstrate the applicability of neutron imaging to quantify the solute dispersion along the interface between heavy water and a cadmium aqueous solution. Then, we monitor the flow of heavy water within two Bentheim sandstone core samples before and after a step of in-situ mineral precipitation. The precipitation of calcium carbonate is induced by reactive mixing of two solutions containing CaCl2 and Na2CO3, either by injecting these two fluids one after each other (sequential experiment) or by injecting them in parallel (co-flow experiment). We use the contrast in neutron attenuation from time-resolved tomograms to derive three-dimensional fluid velocity field by using an inversion technique based on the advection-dispersion equation. Results show mineral precipitation induces a wider distribution of local flow velocities and leads to alterations in the main flow pathways. The flow distribution appears to be independent of the initial distribution in the sequential experiment, while in the co-flow experiment, we observed that higher initial local fluid velocities tended to increase slightly following precipitation. The outcome of this study contributes to progressing the knowledge in the domain of reactive solute and contaminant transport in the subsurface using the promising technique of neutron imaging.","calcium carbonate precipitation; fluid flow; neutron and X-ray microtomography; porous rock","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:e383350a-2946-4d44-9383-e59253326e31","http://resolver.tudelft.nl/uuid:e383350a-2946-4d44-9383-e59253326e31","Quantum Technologies: a Hermeneutic Technology Assessment Approach","Possati, L.M. (TU Delft Ethics & Philosophy of Technology)","","2024","This paper develops a hermeneutic technology assessment of quantum technologies. It offers a “vision assessment” of quantum technologies that can eventually lead to socio-ethical analysis. Section 2 describes this methodological approach and in particular the concept of the hermeneutic circle applied to technology. Section 3 gives a generic overview of quantum technologies and their impacts. Sections 4 and 5 apply the hermeneutic technology assessment approach to the study of quantum technologies. Section 5 proposes distinguishing three levels in the analysis of the creation and communication of social meanings to quantum technologies: (a) fictions, (b) popularization, and (c) scientific journalism. Section 6 analyzes the results and defines some lines of action to increase social acceptance and trust in quantum technologies. The aim of this paper is to contribute to the debate on quantum technologies by enhancing the reflection on them and their potential, as well as illustrating the complexity of technological innovation and the need to shape it.","Hermeneutics; Innovation; Quantum technology; Technology assessment","en","journal article","","","","","","","","","","","Ethics & Philosophy of Technology","","",""
"uuid:2caaaa11-b205-4021-8f34-c6d5ad8f38a7","http://resolver.tudelft.nl/uuid:2caaaa11-b205-4021-8f34-c6d5ad8f38a7","cjdb: A Simple, Fast, and Lean Database Solution for the CityGML Data Model","Powałka, Leon (Student TU Delft); Poon, Chris (Student TU Delft); Xia, Yitong (Student TU Delft); Meines, Siebren (Student TU Delft); Yan, Lan (Student TU Delft); Cai, Yuduan (Student TU Delft); Stavropoulou, G. (TU Delft Urban Data Science); Dukai, B. (3DGI); Ledoux, H. (TU Delft Urban Data Science)","Kolbe, Thomas H. (editor); Donaubauer, Andreas (editor); Beil, Christof (editor)","2024","When it comes to storing 3D city models in a database, the implementation of the CityGML data model can be quite demanding and often results in complicated schemas. As an example, 3DCityDB, a widely used solution, depends on a schema having 66 tables, mapping closely the CityGML architecture. In this paper, we propose an alternative (called ‘cjdb’) for storing CityGML models efficiently in PostgreSQL with a much simpler table structure and data model design (only 3 tables are necessary). This is achieved by storing the attributes and geometries of the objects directly in JSON. In the case of the geometries we thus adopt the Simple Feature paradigm and we use the structure of CityJSON. We compare our solution against 3DCityDB with large real-world 3D city models, and we find that cjdb has significantly lower demands in storage space (around a factor of 10), allows for faster import/export of data, and has a comparable data retrieval speed with some queries being faster and some slower. The accompanying software (importer and exporter) is available at https://github.com/cityjson/cjdb/ under a permissive open-source license.","CityGML; 3DCityDB; 3D modelling; DBMS; CityJSON","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-21","","","Urban Data Science","","",""
"uuid:c8ee6c57-73b0-4ae3-9030-595a4b2a696a","http://resolver.tudelft.nl/uuid:c8ee6c57-73b0-4ae3-9030-595a4b2a696a","Introducing a force-matched united atom force field to explore larger spatiotemporal domains in molecular dynamics simulations of bitumen","Assaf Martinez-Streignard, E.I. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Lin, P. (TU Delft Pavement Engineering; Rijkswaterstaat); Erkens, S. (TU Delft Pavement Engineering; Rijkswaterstaat)","","2024","This paper presents a United Atom (UA) force field for simulating hydrocarbon molecules in bituminous materials, integrating explicit hydrogens into beads with their parent atom. This method simplifies all-atom molecular models, significantly accelerating Molecular Dynamics (MD) simulations of bitumen by 10 to 100 times. Key advantages include halving the particle count, eliminating complex hydrogen interactions, and decreasing the degrees of freedom of the molecules. Developed by mapping forces from an all-atom model to the centers of mass of UA model beads, the force field ensures accurate replication of energies, forces, and molecular conformations, mirroring properties like pressure and density. It features 17 bead types and 287 interaction types, encompassing various hydrocarbon molecules. The UA force field's stability, surpassing all-atom models, is a notable achievement. This stability, stemming from smoother potential energy surfaces, leads to consistent property measurements and improved stress tensor accuracy. It enables the extension of MD simulations to larger spatiotemporal scales, crucial for understanding complex phenomena such as phase separation in bituminous materials. This foundational work sets the stage for future developments, including refining parameters and introducing new bead types, to enhance the modeling capabilities of the force field, thereby advancing the application and understanding of bituminous materials.","Bitumen; Coarse-graining; Force field; Force-matching; Molecular dynamics; Morphology; Phase separation; Segregation","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:ad99d302-4b18-4b76-8997-ebae12218ee5","http://resolver.tudelft.nl/uuid:ad99d302-4b18-4b76-8997-ebae12218ee5","First International Workshop on Worker-Robot Relationships: Exploring Transdisciplinarity for the Future of Work with Robots","Zaga, Cristina (University of Twente); Lupetti, M.L. (TU Delft Design Aesthetics); Forster, D. (TU Delft Human-Robot Interaction); Murray-Rust, D.S. (TU Delft Human Information Communication Design); Prendergast, J.M. (TU Delft Human-Robot Interaction); Abbink, D.A. (TU Delft Human-Centred Artificial Intelligence; TU Delft Human-Robot Interaction)","","2024","In Industry 5.0, cognitive robots and workers will engage in evolving and reciprocal relations, which we call worker-robot relationships (WRRs). To enable evidence-based work futures with workers, we must co-develop WRRs and understand their impact on work, workers, management, and society. To this end, we posit that the HRI field should work beyond disciplines and include value-driven and plural perspectives through transdisciplinary research done with and for workers. However, WRRs and transdisciplinarity pose unique technical, design, and methodological challenges yet to be explored. We propose a workshop to engage the HRI community working on Industry 5.0, aiming at 1) taking stock of current WRR-related challenges in relevant disciplines, 2) collectively kick-off the exploration of a joint research agenda, 3) preliminary examining if and how transdisciplinarity could help the HRI community, and 4) start discussing how to deal with such complex knowledge integration in practice.","future of work with robots; transdisciplinarity; worker-robot relationships","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-11","","","Design Aesthetics","","",""
"uuid:6d572537-9f92-450a-a9a4-61f9f3021d6b","http://resolver.tudelft.nl/uuid:6d572537-9f92-450a-a9a4-61f9f3021d6b","Assistive Applications, Accessibility, and Disability Ethics in HRI","Allen, Katherine H. (Tufts University); Aronson, Reuben M. (Tufts University); Bhattacharjee, Tapomayukh (Cornell University); Broz, F. (TU Delft Interactive Intelligence); Chang, Mai Lee (Carnegie Mellon University); Collier, Maggie (Carnegie Mellon University); Faulkner, Taylor Kessler (University of Washington); Lee, Hee Rin (Michigan State University); Neto, Isabel (University of Lisbon)","","2024","This full-day workshop addresses the problems of accessibility in HRI and the interplay of ethical considerations for disability-centered design and research, accessibility concerns for disabled researchers, and the design of assistive HRI technologies. We invite authors to submit extended abstracts (up to 2 pages, excluding references) and short papers (up to 4 pages, excluding references) on a range of topics relevant to ethics, accessibility, and assistive applications in HRI, including critical reflections on methodologies, design papers on human-centered or anti-ableist assistive technology, and papers from those outside the HRI community who may have insight to share on these concerns. The workshop will use a hybrid format to allow participants who due to disability, geographic, financial, or other constraints, are unable to travel, and will feature keynote speakers, panel discussions, and breakout sessions.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-11","","","Interactive Intelligence","","",""
"uuid:ef124a08-8ffe-423f-9bed-0b58b678e7ab","http://resolver.tudelft.nl/uuid:ef124a08-8ffe-423f-9bed-0b58b678e7ab","Synthesis, solubility and thermodynamic properties of N-A-S-H gels with various target Si/Al ratios","Chen, Y. (TU Delft Materials and Environment; South China University of Technology); de Lima, Luiz Miranda (Student TU Delft); Li, Zhenming (Harbin Institute of Technology); Ma, Bin (Paul Scherrer Institut); Lothenbach, Barbara (Swiss Federal Laboratories for Materials Science and Technology (Empa)); Yin, Suhong (South China University of Technology); Yu, Qijun (South China University of Technology); Ye, G. (TU Delft Materials and Environment)","","2024","The synthesis of N-A-S-H gel with high Si/Al ratios (>2) has been rarely reported in the literature, leaving the establishment of a reliable synthesis route as an open challenge. This paper aims to synthesize N-A-S-H gels with Si/Al ratios ranging from 1 to 3 and establish their thermodynamic database. The effects of reaction temperature, reaction time, initial Si/Al, concentration of reactants and pH of the matrix on the Si/Al ratios of the synthesized N-A-S-H gel were investigated. Results showed that N-A-S-H gels with target Si/Al ratios can be synthesized by controlling the concentration of reactants, pH and initial Si/Al ratios. The solubility products of the obtained N-A-S-H gels were determined via dissolution tests at different temperatures, to determine thermodynamic data. The development of this experimentally derived thermodynamic database of N-A-S-H gels constitutes a crucial step in the advancement of thermodynamic modeling of geopolymer, providing valuable insight into geopolymer reactions and phase assemblages.","N-A-S-H gel; Si/Al ratio; Sol-gel method; Solubility product; Thermodynamic properties","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:e68291f7-fbaf-42aa-a019-ff95d202ba4c","http://resolver.tudelft.nl/uuid:e68291f7-fbaf-42aa-a019-ff95d202ba4c","A finite element thermomechanical analysis of the development of wheel polygonal wear","He, C. (TU Delft Railway Engineering); Yang, Z. (TU Delft Railway Engineering); Zhang, P. (TU Delft Railway Engineering); Li, S. (TU Delft Railway Engineering); Naeimi, M. (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","","2024","Polygonal wear is a type of damage commonly observed on the railway wheel tread. It induces wheel-rail impacts and consequent train/track components failure. This study presents a finite element (FE) thermomechanical wheel-rail contact model, which is able to cope with the three possible generation and development mechanisms of polygonal wear: initial defects, thermal effect, and structural dynamics. The polygonal wear-induced impact contact and further development of wear are simulated. The simulated elastic contact solutions are verified against the program CONTACT. Different material properties (elastic, elasto-plastic and elasto-plastic-thermo, i.e. with thermal softening) and initial polygonal profiles are then applied to the FE model to investigate the influence of wheel/rail material and wear amplitude on wheel-rail contact stress and wear development. The simulations indicate that the wheel-rail impact-induced temperature may reach up to 362 ℃ at the contact interface, and the high temperature at the contact area influences wheel-rail contact stress and wear depth.","Finite element model; Polygonal wear; Thermal effect; Wheel-rail contact","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:5fcc82ce-8371-40fb-a0e8-afa54887def4","http://resolver.tudelft.nl/uuid:5fcc82ce-8371-40fb-a0e8-afa54887def4","Optimal Configuration of Omega-Kappa FF-SAR Processing for Specular and Non-Specular Targets in Altimetric Data: The Sentinel-6 Michael Freilich Study Case","Amraoui, Samira (Collecte Localisation Satellites); Guccione, Pietro (ARESYS SRL); Moreau, Thomas (Collecte Localisation Satellites); Alves, Marta (Collecte Localisation Satellites); Altiparmaki, O. (TU Delft Astrodynamics & Space Missions); Peureux, Charles (Collecte Localisation Satellites); Recchia, Lisa (ARESYS SRL); Maraldi, Claire (Centre National pour l’Etudes Spatiales); Boy, François (CNES Centre National d'Etudes Spatiales); Donlon, Craig (European Space Agency (ESA))","","2024","In this study, the full-focusing (FF) algorithm is reviewed with the objective of optimizing it for processing data from different types of surfaces probed in altimetry. In particular, this work aims to provide a set of optimal FF processing parameters for the Sentinel-6 Michael Freilich (S6-MF) mission. The S6-MF satellite carries an advanced radar altimeter offering a wide range of potential FF-based applications which are just beginning to be explored and require prior optimization of this processing. In S6-MF, the Synthetic Aperture Radar (SAR) altimeter acquisitions are known to be aliased in the along-track direction. Depending on the target, aliasing can be tolerated or may be a severe impairment to provide the level of performance expected from FF processing. Another key aspect to consider in this optimization study is the unprecedented resolution of the FF processing, which results in a higher posting rate than the standard SAR processing. This work investigates the relationship between posting rate and noise levels and provides recommendations for optimal algorithm configurations in various scenarios, including transponder, open ocean, and specular targets like sea-ice and inland water scenes. The Omega–Kappa (WK) algorithm, which has demonstrated superior CPU efficiency compared to the back-projection (BP) algorithm, is considered for this study. But, unlike BP, it operates in the Doppler frequency domain, necessitating further precise spectral and time domain settings. Based on the results of this work, real case studies using S6-MF acquisitions are presented. We first compare S6-MF FF radargrams with Sentinel-1 (S1) images to showcase the potential of optimally configured FF processing. For highly specular surfaces such as sea-ice, distinct techniques are employed for lead signature identification. S1 relies on image-based lineic reconstruction, while S6-MF utilizes phase coherency of focalized pulses for lead detection. The study also delves into two-dimensional wave spectra derived from the amplitude modulation of image/radargrams, with a focus on a coastal example. This case is especially intriguing, as it vividly illustrates different sea states characterized by varying spectral peak positions over time.","","en","journal article","","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:c5e3916b-e2b3-4244-8541-432dedc10402","http://resolver.tudelft.nl/uuid:c5e3916b-e2b3-4244-8541-432dedc10402","Dataslip: Into the Present and Future(s) of Personal Data","Gomez Ortega, A. (TU Delft Internet of Things); Noortman, Renee (Eindhoven University of Technology); Bourgeois, Jacky (TU Delft Internet of Things); Kortuem, G.W. (TU Delft Internet of Things)","","2024","Most people are entangled with an ever-growing trail of data that results from their daily interactions with products and services. Yet, they are hardly aware of the nature and characteristics of the data within this trail. We design dataslip, a provocative artifact that materializes the personal data trail into a receipt and aims to elicit creepiness. We demonstrate dataslip at two events in Delft, The Netherlands. Dataslip is a starting point to foster conversations with local community members about the underlying challenges and potential alternatives to personal data collection and use. We use these as prompts for further speculation through a collaborative futuring exercise with children, where we part from challenges towards hopeful and empowering futures. We contribute with an artifact that invites individuals to interrogate the current personal data practices they are embedded in and a set of five speculative design scenarios that suggest hopeful and empowering alternatives.","Personal Data; Prototyping; Speculative Design; Futuring","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Internet of Things","","",""
"uuid:29979dc6-eee3-4c7b-905b-0dd9c0424e63","http://resolver.tudelft.nl/uuid:29979dc6-eee3-4c7b-905b-0dd9c0424e63","Sensitivities of atmospheric composition and climate to altitude and latitude of hypersonic aircraft emissions","Pletzer, Johannes (TU Delft Aircraft Noise and Climate Effects; German Aerospace Center (DLR), Institute of Atmospheric Physics); Grewe, V. (TU Delft Aircraft Noise and Climate Effects)","","2024","Hydrogen-powered hypersonic aircraft are designed to travel in the middle stratosphere at approximately 30–40 km. These aircraft can have a considerable impact on climate-relevant species like stratospheric water vapor, ozone, and methane and thus would contribute to climate warming. The impact of hypersonic aircraft emissions on atmospheric composition and, in turn, on radiation fluxes differs strongly depending on cruise altitude. However, in contrast to variations in the altitude of emission, differences from variations in the latitude of emission are currently unknown. Using an atmospheric chemistry general circulation model, we show that a variation in the latitude of emission can have a larger effect on perturbations and stratospheric-adjusted radiative forcing than a variation in the altitude of emission. Our results include the individual impacts of water vapor and nitrogen oxide emissions, as well as unburned hydrogen, on middle-atmospheric water vapor, ozone, and methane and the resulting radiative forcing. Water vapor perturbation lifetime continues the known tropospheric increase with altitude and reaches almost 6 years in the middle stratosphere. Our results demonstrate how atmospheric composition changes caused by emissions of hypersonic aircraft are controlled by large-scale processes like the Brewer–Dobson circulation and, depending on the latitude of emission, local phenomena like polar stratospheric clouds.
The analysis includes a model evaluation of ozone and water vapor with satellite data and a novel approach to reduce simulated years by one-third. A prospect for future hypersonic research is the analysis of seasonal sensitivities and simulations with emissions from combustion of liquefied natural gas instead of liquid hydrogen.","","en","journal article","","","","","","","","","","","Aircraft Noise and Climate Effects","","",""
"uuid:9ec858e0-ff55-45a5-b331-442635eeb3f3","http://resolver.tudelft.nl/uuid:9ec858e0-ff55-45a5-b331-442635eeb3f3","Microplastics in terrestrial ecosystem: Exploring the menace to the soil-plant-microbe interactions","Zhai, Yujia (Beijing Normal University); Bai, Junhong (Beijing Normal University); Chang, Pengfei (Chinese Academy of Sciences; Guilin University of Technology); Liu, Zhe (Beijing Normal University); Wang, Yaqi (Beijing Normal University); Liu, G. (TU Delft Sanitary Engineering; Chinese Academy of Sciences; University of Chinese Academy of Sciences); Cui, Baoshan (Beijing Normal University); Peijnenburg, Willie (Universiteit Leiden; Rijksinstituut voor Volksgezondheid en Milieu (RIVM)); Vijver, Martina G. (Universiteit Leiden)","","2024","Microplastics (MPs), miniscule plastic particles measuring less than 5 mm in size, have become a concern in terrestrial ecosystems, with primarily agricultural and wetland soils being the soils with highest plastic loadings. The adverse effect of MPs might lead to changes in physicochemical and biological characteristics of soil including soil properties, microbial communities, plants, as well as the potential or affirmed correlations among them. Therefore, understanding the risks and effects of MPs, particularly within the soil-plant-microbe context is challenging and have become a subject of substantial scientific inquiry. This comprehensive review is focused on the effects of MPs on the rhizosphere and plant-microbe symbiotic relationships, with implications for plant growth and ecosystem-level nutrient fluxes. MPs alter soil physicochemical properties, microbial community composition, and enzymatic activities in the rhizosphere, influencing nutrient availability and uptake by plants. These changes in the rhizosphere can disrupt plant-microbe symbiotic interactions, such as mycorrhizal associations and nitrogen-fixing symbioses, ultimately impacting plant growth and the cycling of nutrients within ecosystems. Furthermore, we elaborate on the effects of MPs on the rhizosphere and plant-microbe symbiotic relationships carrying implications for plant growth and ecosystem-level nutrient fluxes. Future research directions and solutions to the microplastics menace acknowledging combined effects of MPs and other contaminants, advanced technologies for MPs identification and quantification, and microbial engineering for MPs remediation. This knowledge of MPs-induced impacts on soil-plant-microbe interactions is essential to generate mitigating actions in soil environmental management and conservation.","Microplastics; Phytotoxicity; Soil microbial community; Soil properties; Soil-plant-microbe interactions; Wetland and agricultural soil","en","review","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:731f8df8-3696-4906-83ba-ab5ecc9598c3","http://resolver.tudelft.nl/uuid:731f8df8-3696-4906-83ba-ab5ecc9598c3","Plastic particles affect N2O release via altering core microbial metabolisms in constructed wetlands","Yang, X. (TU Delft Sanitary Engineering; Chongqing University; Westlake University; Chinese Academy of Sciences; Ocean University of China); Chen, Yi (Chongqing University); Liu, Tao (Chongqing University); Zhang, Lu (Westlake University; Westlake Institute for Advanced Study); Wang, Hui (Westlake University; Westlake Institute for Advanced Study); Chen, Mengli (Chongqing University); He, Qiang (Chongqing University); Liu, G. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Ju, Feng (Westlake University; Westlake Institute for Advanced Study)","","2024","Constructed wetlands (CWs) have been proven to effectively immobilize plastic particles. However, little is known about the differences in the impact of varying sized plastic particles on nitrous oxide (N2O) release, as well as the intervention mechanisms in CWs. Here, we built a lab-scale wetland model and introduced plastic particles of macro-, micro-, and nano-size at 100 μg/L for 370 days. The results showed that plastic particles of all sizes reduced N2O release in CWs, with the degrees being the strongest for the Nano group, followed by Micro and Macro groups. Meanwhile, 15N- and 18O-tracing experiment revealed that the ammoxidation process contributed the most N2O production, followed by denitrification. While for every N2O-releasing process, the contributing proportion of N2O in nitrification-coupled denitrification were most significantly cut down under exposing to macro-sized plastics and had an obvious increase in nitrifier denitrification in all groups, respectively. Finally, we revealed the three mechanism pathways of N2O release reduction with macro-, micro-, and nano-sized plastics by impacting carbon assimilation (RubisCO activity), ammonia oxidation (gene amo abundance and HAO activity), and N-ion transmembrane and reductase activities, respectively. Our findings thus provided novel insights into the potential effects of plastic particles in CWs as an eco-technology.","Carbon metabolism; Constructed wetlands; Nitrogen metabolism; Nitrous oxide; Plastic particles","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-22","","","Sanitary Engineering","","",""
"uuid:19b80c41-ef6f-42c0-9a81-2c600c9dd53f","http://resolver.tudelft.nl/uuid:19b80c41-ef6f-42c0-9a81-2c600c9dd53f","Large deviations for Markov processes with switching and homogenisation via Hamilton–Jacobi–Bellman equations","Della Corte, S. (TU Delft Applied Probability); Kraaij, R.C. (TU Delft Applied Probability)","","2024","We consider the context of molecular motors modelled by a diffusion process driven by the gradient of a weakly periodic potential that depends on an internal degree of freedom. The switch of the internal state, that can freely be interpreted as a molecular switch, is modelled as a Markov jump process that depends on the location of the motor. Rescaling space and time, the limit of the trajectory of the diffusion process homogenises over the periodic potential as well as over the internal degree of freedom. Around the homogenised limit, we prove the large deviation principle of trajectories with a method developed by Feng and Kurtz based on the analysis of an associated Hamilton–Jacobi–Bellman equation with an Hamiltonian that here, as an innovative fact, depends on both position and momenta.","Large deviations; Switching Markov process; Hamilton–Jacobi equation; Viscosity solutions; Comparison principle","en","journal article","","","","","","","","","","","Applied Probability","","",""
"uuid:c5603098-a6c2-4f98-9b24-2789b6005df7","http://resolver.tudelft.nl/uuid:c5603098-a6c2-4f98-9b24-2789b6005df7","Analyzing natural bed-level dynamics to mitigate the morphological impact of river interventions","van Denderen, R. Pepijn (University of Twente; HKV Lijn in Water B.V.); Schielen, R.M.J. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Rijkswaterstaat); Paarlberg, Andries J. (HKV Lijn in Water B.V.); Reneerkens, Michiel (Rijkswaterstaat); Augustijn, Denie C. M. (University of Twente)","","2024","Local river interventions, such as channel narrowing or side channels, are often necessary to maintain safety, ecology, or navigation. Such interventions have different effects on the river's bed morphology during periods of high- and low-discharge events. Mapping the bed-level variations for different discharge levels and understanding these effects can provide new opportunities for the design of interventions in multifunctional rivers. At any moment, the local bed level in a river is composed of bed-level changes that occur at various spatial and temporal scales. These changes consist of bed aggradation/degradation trends on a large scale, on an intermediate scale bed-level variations as a result of discharge fluctuations, and on small-scale moving river bed forms like dunes. Using the river Waal in the Netherlands as a case study, we analyze the intermediate-term bed-level changes resulting from discharge fluctuations (dynamic component) and propose adaptations to the design of floodplain interventions such that possible negative impact on the local bed-level changes is minimized. Time series of bed levels along two 10 km stretches of the case study are considered for a period of 16 years (2005–2020). Using a wavelet transform, we isolate bed-level variations resulting from discharge events. These bed-level variations are presented based on the magnitude of the discharge event and are compiled in an interactive atlas of river morphodynamics, allowing us to mitigate the impact of interventions. This will help river managers in the design of interventions and lead to improved management, operation, and maintenance of multifunctional rivers.","interventions; river engineering; river morphodynamics; river Waal; wavelet transform","en","journal article","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:f5b485d0-7b70-494a-82ac-699a13128b48","http://resolver.tudelft.nl/uuid:f5b485d0-7b70-494a-82ac-699a13128b48","A single-input state-switching building block harnessing internal instabilities","ten Wolde, M.A. (TU Delft Mechatronic Systems Design); Farhadi Machekposhti, D. (TU Delft Mechatronic Systems Design)","","2024","Bistable mechanisms are prevalent across a broad spectrum of applications due to their ability to maintain two distinct stable states. Their energy consumption is predominantly confined to the process of state transitions, thereby enhancing their efficiency. However, the transition often requires two distinct digital inputs, implicating the requirement of multiple actuators. Here, we propose an elastic and contactless design strategy for inducing state transitions in bistable mechanisms, requiring only a single digital input. The strategy leverages internal information, interpreted as system state, as an extra input to make a weighted decision for transitioning to the subsequent state. We characterize the behavior using a spring-based rigid-body model, consisting of a column near bifurcation, combined with a non-linear spring connected to a bistable element that represents the information state. The results show that a nonlinear spring with a quadratic stiffness function, i.e., representing internal instability, is crucial for regulating state-switching behavior. We then demonstrate this design strategy by developing a monolithic and compliant design embodiment and experimentally evaluate its behavior.","Bistable mechanism; Compliant mechanism; Elastic instability; Mechanical computing; State switching","en","journal article","","","","","","","","","","","Mechatronic Systems Design","","",""
"uuid:6227da11-a508-489f-878b-32733374f72d","http://resolver.tudelft.nl/uuid:6227da11-a508-489f-878b-32733374f72d","Data Handling: Good Practices in the Context of Naturalistic Driving Studies","Al Haddad, Christelle (Technische Universität München); Alam, Md Rakibul (Technische Universität München); Papadimitriou, E. (TU Delft Safety and Security Science); Brijs, Tom (University of Hasselt); Antoniou, Constantinos (Technische Universität München)","","2024","Naturalistic driving studies (NDS) have recently gained attention as a way of instrumenting vehicles in an unobtrusive way and collecting driving data over long periods of time. Aiming at eventually modeling driving behavior, NDS are often a part of larger scale studies. These studies involve several stakeholders who are responsible for different components of the data collection and analysis, and thus are inevitably confronted with challenges in the data management pipeline. The aim of this paper is to develop standard protocols that could be used as guidelines for data handling in the context of NDS. In the development of these protocols, we first review data handling strategies used in previous studies, focusing on data collection, preparation, storage, as well as ethical and legal considerations. This review helps us draw lessons, based on which methods are developed to answer the gaps and challenges arising from handling NDS data. We then introduce a case study, the i–DREAMS project, to show the applicability of the data handling framework. Finally, we showcase standard protocols for data handling, that could serve as data handling guidelines for future studies.","naturalistic driving studies; data handling; standard protocols; safer roads; efficient mobility; transportation technology","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:e60b081d-43b8-4574-92b1-0a0c7e61ab99","http://resolver.tudelft.nl/uuid:e60b081d-43b8-4574-92b1-0a0c7e61ab99","29.2 A Cryo-CMOS Controller with Class-DE Driver and DC Magnetic-Field Tuning for Color-Center-Based Quantum Computers","Enthoven, L.A. (TU Delft QCD/Sebastiano Lab); Fakkel, N.E. (TU Delft QCD/Babaie Lab); Bartling, H.P. (TU Delft Quantum Internet Division; TU Delft QuTech Advanced Research Centre); van Riggelen, M. (TU Delft QID/Taminiau Lab; TU Delft QuTech Advanced Research Centre); Schymik, K.N. (TU Delft QID/Taminiau Lab; TU Delft QuTech Advanced Research Centre); Yun, J. (TU Delft QID/Taminiau Lab; TU Delft QuTech Advanced Research Centre); Tsapanou Katranara, E. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre); Vollmer, R. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre); Taminiau, T.H. (TU Delft QID/Taminiau Lab; TU Delft QuTech Advanced Research Centre); Sebastiano, F. (TU Delft Quantum Circuit Architectures and Technology); Babaie, M. (TU Delft Electronics)","","2024","Color-center quantum bits (qubits), such as the Nitrogen-Vacancy center (NV) in diamond, have demonstrated entanglement between remote (>1.3km) qubits and excellent coherence times [1], all while operating at a few Kelvins. Compared to other qubit technologies typically operating at mK temperatures, the higher operating temperature of NVs enables scalable 3D integration with cryo-CMOS control electronics [2], provides significantly more cooling power, and removes the interconnect bottleneck between the qubits and the electronics in prior art [3-5]. Yet, no cryo-CMOS controller for NV-based quantum computers (QC) has been demonstrated.","","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-13","","Quantum Internet Division","QCD/Sebastiano Lab","","",""
"uuid:2f31faaa-3d1d-4a8a-903a-5de2a80a4d09","http://resolver.tudelft.nl/uuid:2f31faaa-3d1d-4a8a-903a-5de2a80a4d09","Artificial intelligence and post-pandemic recovery","Ersoy, A. (TU Delft Urban Development Management); Cavalcante Siebert, L. (TU Delft Interactive Intelligence); Wang, T. (TU Delft Design & Construction Management); Chan, P.W.C. (TU Delft Design & Construction Management)","Andres, Lauren (editor); Bryson, John R. (editor); Ersoy, Aksel (editor); Reardon, Louise (editor)","2024","Artificial Intelligence (AI) has become one of the most dicussed topics of today and are being used to support solving complex problems. AI has given opportunities for efficiency, control, safety while raising issues around trust, optimism and responsibility. One of the prominent features of AI resides in the digitalization of the built environment. Optimizing the built environment to improve quality of life, adapt to climate change and respond to crises requires strategies to redesign, reproduce and manage the traditional ways the built environment has been shaped. In this chapter, we present demonstate how we can use AI for post-pandemic recovery. To do that, we first start with addressing digital transformation and the role of AI. We then discuss how we can accelerate this transformation in cities. We will reflect on the covid-19 crises and the impact of the crises in the built environment. We argue that the use of AI raises new possibilities, questions and problems around how we can better organize the built environment and more inclusive participation while supporting existing logics of the built environment.","artificial intelligence; digitalization; built environment; system change","en","book chapter","Edward Elgar Publishing","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-12","","","Urban Development Management","","",""
"uuid:90e6a7f9-ae02-4273-b5dc-a29cfb54bb90","http://resolver.tudelft.nl/uuid:90e6a7f9-ae02-4273-b5dc-a29cfb54bb90","Fragmented recoveries and proactive adaptability: New paradigm shifts, and theoretical directions to unpacking recovery processes and behavioural change","Andres, Lauren (University College London (UCL)); Bryson, John R. (University of Birmingham); Ersoy, A. (TU Delft Urban Development Management); Reardon, Louise (University of Birmingham)","Andres, Lauren (editor); Bryson, John R. (editor); Ersoy, Aksel (editor); Reardon, Louise (editor)","2024","The nature of shocks and crisis is highly diverse; crises and shocks tend to conglomerate rather than occur as single events. People and places are affected differently and have distinct abilities and resources to respond, cope and recover. Key here are path-dependent socio-economic living conditions along with pre-existent intersectional burdens that are constitutive of the everyday abilities of people and places to recover, to some extent, from shocks. There is not one type of recovery, but several parallel recovery processes. Such recoveries are deeply fragmented and reflect the harsh realities of inequitable societies which are simultaneously risk and recovery societies. Places, people, and policy are unprepared for new crises that would have similar (or worse) impacts than the COVID-19 pandemic. New theoretical development is required to characterise the new paradigm of recovery society which is based on understanding how society responds in practice to the direct, indirect, induced, and latent impacts of shocks and hazards.","fragmented recoveries; proactive adaptability; inequalities; behavioural changes; preparedness; recovery society","en","book chapter","Edward Elgar Publishing","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-12","","","Urban Development Management","","",""
"uuid:b7f6902b-69fd-489f-aad8-21e950cd3224","http://resolver.tudelft.nl/uuid:b7f6902b-69fd-489f-aad8-21e950cd3224","Editorial","Llombart, Nuria (TU Delft Tera-Hertz Sensing); Hegmann, Frank (University of Alberta); Song, Ho Jin (Pohang University of Science and Technology)","","2024","","","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-05","","","Tera-Hertz Sensing","","",""
"uuid:552766c2-3cfc-439d-9091-9a88e28e1b9c","http://resolver.tudelft.nl/uuid:552766c2-3cfc-439d-9091-9a88e28e1b9c","Exciton Transport in a Germanium Quantum Dot Ladder","Hsiao, T. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Cova Fariña, P. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Oosterhout, S.D. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; TNO); Jirovec, D. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Zhang, X. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); van Diepen, C.J. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Lawrie, W.I.L. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, C.A. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Sammak, A. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; TNO); Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Veldhorst, M. (TU Delft QN/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Vandersypen, L.M.K. (TU Delft QuTech Advanced Research Centre; TU Delft QN/Vandersypen Lab; Kavli institute of nanoscience Delft)","","2024","Quantum systems with engineered Hamiltonians can be used to study many-body physics problems to provide insights beyond the capabilities of classical computers. Semiconductor gate-defined quantum dot arrays have emerged as a versatile platform for realizing generalized Fermi-Hubbard physics, one of the richest playgrounds in condensed matter physics. In this work, we employ a germanium 4×2 quantum dot array and show that the naturally occurring long-range Coulomb interaction can lead to exciton formation and transport. We tune the quantum dot ladder into two capacitively coupled channels and exploit Coulomb drag to probe the binding of electrons and holes. Specifically, we shuttle an electron through one leg of the ladder and observe that a hole is dragged along in the second leg under the right conditions. This corresponds to a transition from single-electron transport in one leg to exciton transport along the ladder. Our work paves the way for the study of excitonic states of matter in quantum dot arrays.","","en","journal article","","","","","","","","","","","QCD/Vandersypen Lab","","",""
"uuid:c95a1306-7cc6-4b7a-842a-da6efc2554f6","http://resolver.tudelft.nl/uuid:c95a1306-7cc6-4b7a-842a-da6efc2554f6","Underwater noise from vibratory pile driving with non-linear frictional pile–soil interaction","Molenkamp, T. (TU Delft Dynamics of Structures); Tsetas, A. (TU Delft Dynamics of Structures); Tsouvalas, A. (TU Delft Dynamics of Structures; TU Delft Offshore Engineering); Metrikine, A. (TU Delft Hydraulic Engineering; TU Delft Engineering Structures)","","2024","Vibratory offshore pile driving offers a potential solution for reducing the underwater noise generated during the installation of foundation piles compared to using impact hammers. Existing noise prediction models are specifically tailored to impact pile driving scenarios. This paper introduces a novel methodology for underwater noise predictions during vibratory pile driving. A non-linear driveability model is utilised to derive realistic non-linear interface friction forces, which are then incorporated into a noise prediction model. The study emphasises the significance of integrating a driveability analysis, revealing substantial differences from traditional models that assume perfect contact between the pile and soil. The authors argue that the proposed model provides more realistic outcomes when considering smooth driving without refusal, in contrast to traditional models designed for impact piling. The results illustrate noticeable deviations in pressure levels and seabed vibrations between the linear and presented methods at the driving frequency and its superharmonics. Furthermore, the research demonstrates that the noise field is highly sensitive to variations in system dynamics and excitation spectrum during driving, using both small- and large-diameter monopiles as examples. This research contributes to developing more effective driving techniques to reduce underwater noise pollution and facilitate sustainable offshore wind turbine installations.","Driveability analysis; Friction; Offshore wind; Underwater noise; Vibratory pile driving","en","journal article","","","","","","","","","","Hydraulic Engineering","Dynamics of Structures","","",""
"uuid:9420af93-fb9b-4af3-bd0b-61abc74586ec","http://resolver.tudelft.nl/uuid:9420af93-fb9b-4af3-bd0b-61abc74586ec","Size effect on compressive strength of foamed concrete: Experimental and numerical studies","Jiang, Nengdong (Shandong University); Ge, Zhi (Shandong University); Wang, Zhiyuan (Shandong Hi-speed Group); Gao, Tianming (Shandong University); Zhang, Hongzhi (Shandong University); Ling, Yifeng (Shandong University); Šavija, B. (TU Delft Materials and Environment)","","2024","This study investigates the size effect on the compressive strength of foamed concrete at the mesoscale level combining X-ray computed tomography (X-CT) and a discrete lattice model. Image segmentation techniques and X-CT were employed to obtain virtual specimens comprising hydrated cement paste and air voids. The lineal-path function and pore size distribution was used to characterise the air void structure. A two-dimensional lattice fracture model of foamed concrete considering different wet densities was established. The model was verified experimentally at a wet density of 700 kg/m3 and then used to predict the strengths of specimens with wet densities of 600 and 800 kg/m3. Square and rectangular specimens (slenderness ratio = 2) with widths of 10, 20, 40, 70.7, and 100 mm were investigated. Results show that the air void structure significantly influences the observed size effect on the compressive strength in the investigated size range. A random forest regressor was used to predict the compressive strength of the foamed concrete; the regressor yielded satisfactory results. Finally, existing analytical size effect models were used to fit the simulated strength. Although good fitting was achieved, special attention should be given to the applicable range and physical meaning of fitted empirical parameters.","Compressive strength; Foamed concrete; Lattice model; Lineal-path function; Size effect","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:b9d09ad4-75e8-40df-95c5-1da8259ef2f9","http://resolver.tudelft.nl/uuid:b9d09ad4-75e8-40df-95c5-1da8259ef2f9","Deep reinforcement learning for process design: Review and perspective","Gao, Q. (TU Delft ChemE/Process Systems Engineering); Schweidtmann, A.M. (TU Delft ChemE/Process Systems Engineering)","","2024","The transformation toward renewable energy and feedstock supply in the chemical industry requires new conceptual process design approaches. Recently, deep reinforcement learning (RL), a subclass of machine learning, has shown the potential to solve complex decision-making problems and aid sustainable process design. However, its suitability in static process design still needs to be examined. We discuss the advantages and disadvantages of RL for process design. Then, we survey state-of-the-art research through three major elements: (1) information representation, (2) agent architecture, and (3) environment and reward. Moreover, we discuss perspectives on underlying challenges and promising future works to unfold the full potential of RL for process design in chemical engineering.","","en","review","","","","","","","","","","","ChemE/Process Systems Engineering","","",""
"uuid:6bde9094-95fe-431a-9d72-f72b2e111b2c","http://resolver.tudelft.nl/uuid:6bde9094-95fe-431a-9d72-f72b2e111b2c","Large-Scale Channel Response to Erosion-Control Measures","Ylla Arbos, C. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Blom, A. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); White, S. R. (University of California); Patzwahl, R. (Federal Waterways Engineering and Research Institute (BAW)); Schielen, R.M.J. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Rijkswaterstaat)","","2024","Erosion-control measures in rivers aim to provide sufficient navigation width, reduce local erosion, or to protect neighboring communities from flooding. These measures are typically devised to solve a local problem. However, local channel modifications trigger a large-scale channel response in the form of migrating bed level and sediment sorting waves. Our objective is to investigate the large-scale channel response to such measures. We consider the lower Rhine River from Bonn (Germany) to Gorinchem (the Netherlands), where numerous erosion-control measures have been implemented since the 1980s. We analyze measured bed level data (1999–2020) around four erosion-control measures, comprising scour filling, bendway weirs, and two fixed beds. To get further insight on the physics behind the observed behavior, we set up an idealized one-dimensional numerical model. Finally, we study how the geometry and spacing of the measures affect channel response. We show that erosion-control measures reduce the sediment flux due to (a) lack of erosion over the measure and (b) sediment trapping upstream of the measure, resulting in downstream-migrating incision waves that travel tens of kilometers at decadal timescales. When the measures are in close proximity, their downstream effects may be amplified. We conclude that, despite fulfilling erosion-control goals at the local scale, erosion-control measures may worsen large-scale channel-bed incision.","channel bed incision; channel response; engineered rivers; erosion-control measures; fixed beds","en","journal article","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:33c5c36b-b35e-44f9-a006-53ff7b6a86c5","http://resolver.tudelft.nl/uuid:33c5c36b-b35e-44f9-a006-53ff7b6a86c5","29.3 A Cryo-CMOS Receiver with 15K Noise Temperature Achieving 9.8dB SNR in 10μs Integration Time for Spin Qubit Readout","Prabowo, B. (TU Delft QCD/Babaie Lab; TU Delft QuTech Advanced Research Centre); Pietx i Casas, O. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre); Montazerolghaem, M.A. (TU Delft Electronics); Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre); Vandersypen, L.M.K. (TU Delft QuTech Advanced Research Centre; TU Delft QN/Vandersypen Lab); Sebastiano, F. (TU Delft Quantum Circuit Architectures and Technology; TU Delft QuTech Advanced Research Centre); Babaie, M. (TU Delft Electronics; TU Delft QuTech Advanced Research Centre)","","2024","Continuous rounds of quantum error correction (QEC) are essential to achieve faulttolerant quantum computers (QCs). In each QEC cycle, thousands of ancilla quantum bits (qubits) must be read out faster than the qubits' decoherence time (<<T2∗~120μs for spin qubits). To address this urgent need, several CMOS receivers operating at cryogenic temperatures (cryo-CMOS RXs) have recently been introduced for gate-based [1] and RF reflectometry [2] readout of spin qubits, as well as transmons' dispersive readout [3]. However, they have a few shortcomings. First, due to the temperatureindependent shot noise of transistors in nanometer CMOS technology [4], their measured noise temperature (TN) is limited to 40K, thus degrading qubit readout fidelity. Second, due to their large TN, prior art showed either only the electrical performance of their chips by applying a relatively large (i.e., -85dBm [2]) modulated signal directly to the RX input [2,3] or offered limited qubit measurements by exploiting a HEMT amplifier prior to the RX [1]. Those issues hinder future monolithic integration between solid-state qubits and readout electronics. This work advances the prior art by (1) introducing a wideband passive amplification circuit at the RX front-end to minimize the shot noise contribution of the active devices, lowering prior art TN by ~2.7x; (2) demonstrating the RX performance in an RF-reflectometry qubit readout scheme without using off-the-shelf LNA prior to the RX.","","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-13","","","QCD/Babaie Lab","","",""
"uuid:6e8d4e52-b9d8-4da1-8805-25c2dd14cfee","http://resolver.tudelft.nl/uuid:6e8d4e52-b9d8-4da1-8805-25c2dd14cfee","Introduction of a human- and keyboard-friendly N-glycan nomenclature","Altmann, Friedrich (BOKU-University of Natural Resources and Life Sciences); Helm, Johannes (BOKU-University of Natural Resources and Life Sciences); Pabst, Martin (TU Delft BT/Environmental Biotechnology); Stadlmann, Johannes (BOKU-University of Natural Resources and Life Sciences)","","2024","In the beginning was the word. But there were no words for N-glycans, at least, no simple words. Next to chemical formulas, the IUPAC code can be regarded as the best, most reliable and yet immediately comprehensible annotation of oligosaccharide structures of any type from any source. When it comes to N-glycans, the venerable IUPAC code has, however, been widely supplanted by highly simplified terms for N-glycans that count the number of antennae or certain components such as galactoses, sialic acids and fucoses and give only limited room for exact structure description. The highly illustrative - and fortunately now standardized - cartoon depictions gained much ground during the last years. By their very nature, cartoons can neither be written nor spoken. The underlying machine codes (e.g., GlycoCT, WURCS) are definitely not intended for direct use in human communication. So, one might feel the need for a simple, yet intelligible and precise system for alphanumeric descriptions of the hundreds and thousands of N-glycan structures. Here, we present a system that describes N-glycans by defining their terminal elements. To minimize redundancy and length of terms, the common elements of N-glycans are taken as granted. The preset reading order facilitates definition of positional isomers. The combination with elements of the condensed IUPAC code allows to describe even rather complex structural elements. Thus, this “proglycan” coding could be the missing link between drawn structures and software-oriented representations of N-glycan structures. On top, it may greatly facilitate keyboard-based mining for glycan substructures in glycan repositories.","N-glycans; nomenclature; structural features","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:b09badd9-a672-4c30-bba5-35f664e9c72a","http://resolver.tudelft.nl/uuid:b09badd9-a672-4c30-bba5-35f664e9c72a","Mechanism and Performance of SBS Polymer Dry-Modified Asphalt Mixture with PCB and TPO from Waste Tires","Li, Yuanyuan (Wuhan Institute of Technology); Li, Jun (Wuhan Institute of Technology); Bai, Tao (Wuhan Institute of Technology); Chen, Anqi (Wuhan Institute of Technology); Gu, Dengjun (Wuhan Institute of Technology); Gao, Y. (TU Delft Pavement Engineering)","","2024","Based on the efficient resource utilization of scrap tires, pyrolysis carbon black (PCB), and pyrolysis oil of waste tire (TPO), scrap tires' products were treated using dry styrene-butadiene-styrene (SBS) polymer modification of asphalt. The products of scrap tires, PCB and TPO, were handled using dry SBS polymer modification of asphalt based on the effective resource use of scrap tires. The consequences of scrap tires, PCB and TPO, were taken using dry SBS polymer modification of asphalt based on the effective resource use of scrap tires. PCB and TPO composite effect seriously degraded. Based on this, the impact of dry SBS polymer modification on the functionality of PCB-TPO-modified asphalt and the mechanism of modification was examined. According to the investigation, the SBS polymer was evenly distributed and fully developed in the asphalt mixture, which significantly enhanced the qualities of asphalt and the asphalt mixture and performed a positive role in the internal structure of the asphalt mixture.","Dry modification; Modified asphalt; Pyrolytic carbon black; Pyrolytic oil; Styrene-butadiene-styrene (SBS) polymer","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-18","","","Pavement Engineering","","",""
"uuid:8687c48a-d5bc-45ec-af71-32e8006db977","http://resolver.tudelft.nl/uuid:8687c48a-d5bc-45ec-af71-32e8006db977","Matrix-Free Parallel Preconditioned Iterative Solvers for the 2D Helmholtz Equation Discretized with Finite Differences","Chen, J. (TU Delft Numerical Analysis); Dwarka, V.N.S.R. (TU Delft Numerical Analysis); Vuik, Cornelis (TU Delft Delft Institute of Applied Mathematics)","van Beurden, M. (editor); Budko, N.V. (editor); Ciuprina, G. (editor); Schilders, W. (editor); Bansal, H. (editor); Barbulescu, R. (editor)","2024","We present a matrix-free parallel iterative solver for the Helmholtz equation related to applications in seismic problems and study its parallel performance. We apply Krylov subspace methods, GMRES, Bi-CGSTAB and IDR(s), to solve the linear system obtained from a second-order finite difference discretization. The Complex Shifted Laplace Preconditioner (CSLP) is employed to improve the convergence of Krylov solvers. The preconditioner is approximately inverted by multigrid iterations. For parallel computing, the global domain is partitioned blockwise. The standard MPI library is employed for data communication. The matrix-vector multiplication and preconditioning operator are implemented in a matrix-free way instead of constructing large, memory-consuming coefficient matrices. These adjustments lead to direct improvements in terms of memory consumption. Numerical experiments of model problems show that the matrix-free parallel solution method has satisfactory parallel performance and weak scalability. It allows us to solve larger problems in parallel to obtain more accurate numerical solutions.","","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-01","","","Numerical Analysis","","",""
"uuid:67864d2c-a5a5-4a4f-9c26-e00f067d4305","http://resolver.tudelft.nl/uuid:67864d2c-a5a5-4a4f-9c26-e00f067d4305","To see or not to see: The effect of observability of the recycled content on consumer adoption of products made from recycled materials","Polyportis, Athanasios (Erasmus Universiteit Rotterdam); Mugge, R. (TU Delft Responsible Marketing and Consumer Behavior; Universiteit van Amsterdam); Magnier, L.B.M. (TU Delft Responsible Marketing and Consumer Behavior)","","2024","Despite their environmental benefits, products made from recycled materials are not readily adopted. Prior studies focused on improving consumer adoption via product attributes and marketing elements, but the impact of product appearance remains a gap in the literature. This research contributes by investigating how observability of the recycled content, as a product appearance intervention, influences consumer adoption of products made from recycled materials. Building on the integrated conceptual framework for consumer response to the visual domain in product design, the findings from three experiments (n1=162, n2=219, n3=320) demonstrate that observability of the recycled content leads to higher purchase intentions (Studies 1, 2 and 3). The underlying process for this effect is that these observable appearance cues trigger identity signaling (Studies 2 and 3). This effect is stronger when the consumption context is public (Study 3). These findings enable practitioners to enhance adoption of these products through altering their appearance.","Products made from recycled materials; Recycling; Sustainability; Identity signaling; Semantic interpretation; Consumer adoption","en","journal article","","","","","","","","","","","Responsible Marketing and Consumer Behavior","","",""
"uuid:7f46a0aa-6bd9-4efb-b611-eec71f021c8c","http://resolver.tudelft.nl/uuid:7f46a0aa-6bd9-4efb-b611-eec71f021c8c","Introducing the 3DCityDB-Tools Plug-In for QGIS","Agugiaro, G. (TU Delft Urban Data Science); Pantelios, Konstantinos (Student TU Delft); León Sánchez, C.A. (TU Delft Urban Data Science); Yao, Zhihang (virtualcitySYSTEMS GmbH); Nagel, Claus (virtualcitySYSTEMS GmbH)","Kolbe, Thomas H. (editor); Donaubauer, Andreas (editor); Beil, Christof (editor)","2024","This paper introduces a new plug-in for QGIS that allows to connect to the free and open-source 3D City Database to load CityGML data, structured as classic GIS layers, into QGIS. The user is therefore not required to be a CityGML specialist, or a SQL expert, as the plug-in takes care of hiding from the user most of the complexity in terms of underlying data model and database schema implementation. The user can therefore load CityGML thematic “layers” (e.g. for buildings, bridges, vegetation, terrain, etc.), explore their geometries in 2D and 3D and access and edit the associated attributes. At the same time, depending on the user privileges, it is possible to delete features from the database using either normal QGIS editing tools, or a “bulk delete” tool, also included. The plug-in is composed of two parts, a server-side one, which must be installed in the 3D City Database instance, and the client-side one, which runs as a QGIS plug-in in strict sense. A GUI-based tool is also provided for database administrators in order to install/uninstall the database-side part of the plug-in, and manage users and their privileges. All in all, the 3DCityDB-Tools plug-in facilitates the access to CityGML data for GIS practitioners from heterogeneous fields and expertise with the common denominator being the well-known QGIS environment.","3D city database; QGIS; CityGML; CityJSON; Plug-in","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-21","","","Urban Data Science","","",""
"uuid:b718a726-74d4-4ec5-bee7-202fd723898d","http://resolver.tudelft.nl/uuid:b718a726-74d4-4ec5-bee7-202fd723898d","Design of morphing wing for aerodynamic performance considering the wing flexibility effects","Navratil, J. (Brno University of Technology); Hostinský, V. (Brno University of Technology); Sodja, J. (TU Delft Group Sodja)","","2024","This paper provides an insight into ongoing research aimed at designing a morphing wing with the ability to continuously adapt its aerodynamic shape. The wing is targeted at a general purpose unmanned aerial vehicle. The morphing wing concept outlined in the paper is based on continuous camber changes of the wing leading and trailing edges, allowing optimal performance in different flight regimes. The aeroelastic tailoring method is used to design the load carrying structure of the wing in order to define the optimal stiffness and strength of the structure, which are considered as fixed in subsequent design steps. The research proposes a novel modular design approach that combines aerodynamic shape optimisation and aeroelastic considerations for designing morphing wing surfaces.","","en","journal article","","","","","","","","","","","Group Sodja","","",""
"uuid:3e8684ec-0ca1-459f-bca0-638cb591bd06","http://resolver.tudelft.nl/uuid:3e8684ec-0ca1-459f-bca0-638cb591bd06","Devices of Articulation: Who Ever Said They Have to Be Smart?","Kolks, L.A.G. (TU Delft Design Aesthetics)","","2024","In this article, I argue to expand the application of the concept “devices of articulation”—a term signifying those artifacts that are purposefully created to articulate public issues: controversial phenomena that are too important not to be considered by designers but are not necessarily solvable by political or scientific means. Whereas problems might be fixed, issues can only be temporarily stabilized. I, therefore, investigate how two design projects—Smogware and the Rain Project—forge new relations, meanings, and consequences among elements that are typically understood to be unrelated, to support public engagement with the issue of environmental pollution.","Design theory; Sociology; Social theory","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-28","","","Design Aesthetics","","",""
"uuid:0e4af207-3298-4671-944f-5fd6dc0cd655","http://resolver.tudelft.nl/uuid:0e4af207-3298-4671-944f-5fd6dc0cd655","The Chvátal–Gomory procedure for integer SDPs with applications in combinatorial optimization","de Meijer, F.J.J. (TU Delft Discrete Mathematics and Optimization); Sotirov, Renata (Tilburg University)","","2024","In this paper we study the well-known Chvátal–Gomory (CG) procedure for the class of integer semidefinite programs (ISDPs). We prove several results regarding the hierarchy of relaxations obtained by iterating this procedure. We also study different formulations of the elementary closure of spectrahedra. A polyhedral description of the elementary closure for a specific type of spectrahedra is derived by exploiting total dual integrality for SDPs. Moreover, we show how to exploit (strengthened) CG cuts in a branch-and-cut framework for ISDPs. Different from existing algorithms in the literature, the separation routine in our approach exploits both the semidefinite and the integrality constraints. We provide separation routines for several common classes of binary SDPs resulting from combinatorial optimization problems. In the second part of the paper we present a comprehensive application of our approach to the quadratic traveling salesman problem ( QTSP ). Based on the algebraic connectivity of the directed Hamiltonian cycle, two ISDPs that model the QTSP are introduced. We show that the CG cuts resulting from these formulations contain several well-known families of cutting planes. Numerical results illustrate the practical strength of the CG cuts in our branch-and-cut algorithm, which outperforms alternative ISDP solvers and is able to solve large QTSP instances to optimality.","integer semidefinite programming; Chvátal-Gomory procedure; total dual integrality; branch-and-cut; quadratic traveling salesman problem","en","journal article","","","","","","","","","","","Discrete Mathematics and Optimization","","",""
"uuid:9064fc3d-b39d-49f6-bd9c-64764980661e","http://resolver.tudelft.nl/uuid:9064fc3d-b39d-49f6-bd9c-64764980661e","The present and future contribution of ships to the underwater soundscape","Possenti, Luca (NIOZ Royal Netherlands Institute for Sea Research); de Nooijer, Lennart (NIOZ Royal Netherlands Institute for Sea Research); de Jong, Christ (TNO); Lam, Frans Peter (TNO); Beelen, Simon (University of Twente); Bosschers, Johan (Maritime Research Institute Netherlands (MARIN)); van Terwisga, T.J.C. (TU Delft Ship Hydromechanics and Structures; Maritime Research Institute Netherlands (MARIN)); Stigter, Marinus (TU Delft Fluid Mechanics); Reichart, Gert Jan (NIOZ Royal Netherlands Institute for Sea Research; Universiteit Utrecht)","","2024","Since the industrial revolution the ocean has become noisier. The global increase in shipping is one of the main contributors to this. In some regions, shipping contributed to an increase in ambient noise of several decibels, especially at low frequencies (10 to 100 Hz). Such an increase can have a substantial negative impact on fish, invertebrates, marine mammals and birds interfering with key life functions (e.g. foraging, mating, resting, etc.). Consequently, engineers are investigating ways to reduce the noise emitted by vessels when designing new ships. At the same time, since the industrial revolution (starting around 1760) greenhouse gas emissions have increased the atmospheric carbon dioxide fraction x(CO2) by more than 100 μmol mol-1. The ocean uptake of approximately one third of the emitted CO2 decreased the average global surface ocean pH from 8.21 to 8.10. This decrease is modifying sound propagation, especially sound absorption at the frequencies affected by shipping noise lower than 10 kHz, making the future ocean potentially noisier. There are also other climate change effects that may influence sound propagation. Sea surface warming might alter the depth of the deep sound speed channel, ice melting could locally decrease salinity and more frequent storms and higher wind speed alter the depth of the thermocline. In particular, modification of the sound speed profile can lead to the appearance of new ducts making specific depths noisier. In addition, ice melting and the increase in seawater temperature will open new shipping routes at the poles increasing anthropogenic noise in these regions. This review aims to discuss parameters that might change in the coming decades, focusing on the contribution of shipping, climate change and economic and technical developments to the future underwater soundscape in the ocean. Examples are given, contrasting the open ocean and the shallow seas. Apart from the changes in sound propagation, this review will also discuss the effects of water quality on ship-radiated noise with a focus on propeller cavitation noise.","climate change; ocean noise; shipping; soundscape; underwater acoustics","en","review","","","","","","","","","","","Ship Hydromechanics and Structures","","",""
"uuid:8886954b-8173-42ea-82e6-a45e01958703","http://resolver.tudelft.nl/uuid:8886954b-8173-42ea-82e6-a45e01958703","Spatial Robotic Experiences as a Ground for Future HRI Speculations","Murray-Rust, D.S. (TU Delft Human Information Communication Design); Gorbet, Matt (Living Architecture System Group, Waterloo); Filthaut, L. (TU Delft Externenregistratie); Lupetti, M.L. (TU Delft Design Aesthetics); van der Helm, A.J.C. (TU Delft Design Conceptualization and Communication); Chiu, Adrian (University of Waterloo); Ianniello, A. (TU Delft Human-Centred Artificial Intelligence; TU Delft Human-Robot Interaction); Beesley, Philip (University of Waterloo)","","2024","This work illustrates how artistic robotic systems can provide a reservoir of unfamiliarity and a basis for speculation, to open the field toward new ways of thinking about HRI. We reflect on a collaborative project between design students, a media art studio, and design researchers working with the baggage handling department of the Schiphol airport. Engaging with the industrial context, we developed 'metabehaviours' - abstracted ideas of processes carried out on the worksite-and passed these over to the students who translated them into robotic enactions using a predefined hardware developed by the media art studio. The resulting visit experience challenges the audience to decode the installation in terms of metabehaviours and their possible relations to industrial HRI. We used this to reflect on the value of conducting artistic and speculative work in HRI and to distil actionable recommendations for future research.","Art; Human-Robot Interaction; Industrial Robotics; Interaction Design; Speculative design","en","conference paper","IEEE","","","","","","","","","","Human Information Communication Design","","",""
"uuid:b1eb6ffa-71ad-4d5f-8726-dc9bc7186732","http://resolver.tudelft.nl/uuid:b1eb6ffa-71ad-4d5f-8726-dc9bc7186732","The magic of ordinary rather than extraordinary resilience?: Higher education and longer-term pandemic impacts","Bryson, John R. (University of Birmingham); Andres, Lauren (University College London (UCL)); Ersoy, A. (TU Delft Urban Development Management); Reardon, Louise (University of Birmingham)","Andres, Lauren (editor); Bryson, John R. (editor); Ersoy, Aksel (editor); Reardon, Louise (editor)","2024","COVID-19 initially closed universities forcing rapid adoption of online teaching. This chapter reflects on pandemic recovery in the context of higher education and explores some of the longer-term impacts that the pandemic has had on academic practice. Recovery is a complex and highly differentiated process and is founded upon resilience that is configured from ordinary rather than extraordinary phenomena. These processes include established social relationships based on extant friendship networks combined with investments in digital skills and related infrastructures. The chapter explores pandemic legacies and higher education focussing on implications for practice as this relates to teaching, learning, research and administration.","higher education; pandemic recovery; ordinary resilience; improvisation; teaching and research","en","book chapter","Edward Elgar Publishing","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-12","","","Urban Development Management","","",""
"uuid:975eb4eb-9c30-4bbd-a07f-5bde6538388d","http://resolver.tudelft.nl/uuid:975eb4eb-9c30-4bbd-a07f-5bde6538388d","Mesoscale modelling of North Sea wind resources with COSMO-CLM: model evaluation and impact assessment of future wind farm characteristics on cluster-scale wake losses","Borgers, Ruben (Katholieke Universiteit Leuven); Dirksen, M. (TU Delft Atmospheric Remote Sensing); Wijnant, Ine L. (Royal Netherlands Meteorological Institute (KNMI)); Stepek, Andrew (Royal Netherlands Meteorological Institute (KNMI)); Stoffelen, Ad (Royal Netherlands Meteorological Institute (KNMI)); Akhtar, Naveed (Helmholtz-Zentrum Hereon); Neirynck, Jérôme (Katholieke Universiteit Leuven); Van de Walle, Jonas (Katholieke Universiteit Leuven); Meyers, Johan (Katholieke Universiteit Leuven); van Lipzig, Nicole P. M. (Katholieke Universiteit Leuven)","","2024","As many coastal regions experience a rapid increase in offshore wind farm installations, inter-farm distances become smaller, with a tendency to install larger turbines at high capacity densities. It is, however, not clear how the wake losses in wind farm clusters depend on the characteristics and spacing of the individual wind farms. Here, we quantify this based on multiple COSMO-CLM simulations, each of which assumes a different, spatially invariant combination of the turbine type and capacity density in a projected, future wind farm layout in the North Sea. An evaluation of the modelled wind climate with mast and lidar data for the period 2008–2020 indicates that the frequency distributions of wind speed and wind direction at turbine hub height are skillfully modelled and the seasonal and inter-annual variations in wind speed are represented well. The wind farm simulations indicate that for a typical capacity density and for SW winds, inter-farm wakes can reduce the capacity factor at the inflow edge of wind farms from 59 % to between 54 % and 30 % depending on the proximity, size and number of the upwind farms. The efficiency losses due to intra- and inter-farm wakes become larger with increasing capacity density as the layout-integrated, annual capacity factor varies between 51.8 % and 38.2 % over the considered range of 3.5 to 10 MW km−2. Also, the simulated efficiency of the wind farm layout is greatly impacted by switching from 5 MW turbines to next-generation, 15 MW turbines, as the annual energy production increases by over 27 % at the same capacity density. In conclusion, our results show that the wake losses in future wind farm clusters are highly sensitive to the inter-farm distances and the capacity densities of the individual wind farms and that the evolution of turbine technology plays a crucial role in offsetting these wake losses.","","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:48946273-07a9-4269-9e49-1026dd1f5ea2","http://resolver.tudelft.nl/uuid:48946273-07a9-4269-9e49-1026dd1f5ea2","Sustainable urban logistics: A case study of waterway integration in Amsterdam","Pourmohammadzia, N. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); van Koningsveld, M. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Van Oord)","","2024","This paper tackles the growing challenges in urban logistics by presenting an optimal distribution network that integrates urban waterways and last-mile delivery, tailored for cities boasting extensive waterway networks. We examine Amsterdam's city center as a case study, prompted by the strain on quay walls, congestion, and emissions, urging a reevaluation of its urban logistics design. We formulate the problem as a two-echelon location routing problem with time windows and introduce a hybrid solution approach for effective resolution. Our algorithm consistently outperforms existing methods, with a superior solution quality, demonstrating its effectiveness across established and newly developed benchmark instances. In our case study, we evaluate the benefits of transitioning from a roadway-centric to a waterway-based system, showcasing significant cost savings (approximately 28 %), reductions in vehicle weight (approximately 43 %), and minimized travel distances (approximately 80 %) within the city center. The integration of electric vehicles enhances environmental sustainability, resulting in a total daily emission reduction of 43.46 kg. Our study underscores the untapped potential of inland waterways in easing urban logistics challenges. Inspired by Amsterdam's experience, global cities can adopt innovative approaches for sustainable logistics, providing valuable insights for managers striving to enhance efficiency, cut costs, and promote sustainable transportation practices.","Combinatorial optimization; Modal shift; Sustainability; Two-echelon location routing; Urban logistics; Waterways","en","journal article","","","","","","","","","","","Rivers, Ports, Waterways and Dredging Engineering","","",""
"uuid:23bdd3f9-4114-456c-879b-2e716a0203f1","http://resolver.tudelft.nl/uuid:23bdd3f9-4114-456c-879b-2e716a0203f1","Effects of idealized land cover and land management changes on the atmospheric water cycle","De Hertog, Steven J. (Vrije Universiteit Brussel); Lopez-Fabara, Carmen E. (Vrije Universiteit Brussel); van der Ent, R.J. (TU Delft Water Resources); Keune, Jessica (Universiteit Gent); Miralles, Diego G. (Universiteit Gent); Portmann, Raphael (Agroscope); Schemm, Sebastian (ETH Zürich); Havermann, Felix (Ludwig Maximilians University); Guo, Suqi (Ludwig Maximilians University)","","2024","Land cover and land management changes (LCLMCs) play an important role in achieving low-end warming scenarios through land-based mitigation. However, their effects on moisture fluxes and recycling remain uncertain, although they have important implications for the future viability of such strategies. Here, we analyse the impact of idealized LCLMC scenarios on atmospheric moisture transport in three different Earth system model (ESMs): the Community Earth System Model (CESM), the Max Planck Institute Earth System Model (MPI-ESM), and the European Consortium Earth System Model (EC-EARTH). The LCLMC scenarios comprise of a full cropland world, a fully afforested world, and a cropland world with unlimited irrigation expansion. The effects of these LCLMC in the different ESMs are analysed for precipitation, evaporation, and vertically integrated moisture flux convergence to understand the LCLMC-induced changes in the atmospheric moisture cycle. Then, a moisture tracking algorithm is applied to assess the effects of LCLMC on moisture recycling at the local (grid cell level) and the global scale (continental moisture recycling). By applying a moisture tracking algorithm on fully coupled ESM simulations we are able to quantify the complete effects of LCLMC on moisture recycling (including circulation changes), which are generally not considered in moisture recycling studies. Our results indicate that cropland expansion is generally causing a drying and reduced local moisture recycling, while afforestation and irrigation expansion generally cause wetting and increased local moisture recycling. However, the strength of this effect varies across ESMs and shows a large dependency on the dominant driver. Some ESMs show a dominance of large-scale atmospheric circulation changes while other ESMs show a dominance of local to regional changes in the atmospheric water cycle only within the vicinity of the LCLMC. Overall, these results corroborate that LCLMC can induce substantial effects on the atmospheric water cycle and moisture recycling, both through local effects and changes in atmospheric circulation. However, more research is needed to constrain the uncertainty of these effects within ESMs to better inform future land-based mitigation strategies.","","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:942fe88e-c461-4c91-887b-429736e0916f","http://resolver.tudelft.nl/uuid:942fe88e-c461-4c91-887b-429736e0916f","Communicating the results of risk-based breast cancer screening through visualizations of risk: a participatory design approach","van Strien-Knippenberg, Inge S. (Amsterdam UMC); Arjangi-Babetti, Hannah (Amsterdam UMC); Timmermans, Danielle R.M. (Amsterdam UMC); Schrauwen, Laura (Amsterdam UMC); Fransen, M.P. (Amsterdam UMC); Melles, M. (TU Delft Applied Ergonomics and Design); Damman, Olga C. (Amsterdam UMC)","","2024","Background: Risk-based breast cancer (BC) screening raises new questions regarding information provision and risk communication. This study aimed to: 1) investigate women’s beliefs and knowledge (i.e., mental models) regarding BC risk and (risk-based) BC screening in view of implications for information development; 2) develop novel informational materials to communicate the screening result in risk-based BC screening, including risk visualizations of both quantitative and qualitative information, from a Human-Centered Design perspective. Methods: Phase 1: Interviews were conducted (n = 15, 40–50 years, 5 lower health literate) on women’s beliefs about BC risk and (risk-based) BC screening. Phase 2: In three participatory design sessions, women (n = 4–6 across sessions, 40–50 years, 2–3 lower health literate) made assignments and created and evaluated visualizations of risk information central to the screening result. Prototypes were evaluated in two additional sessions (n = 2, 54–62 years, 0–1 lower health literate). Phase 3: Experts (n = 5) and women (n = 9, 40–74 years) evaluated the resulting materials. Two other experts were consulted throughout the development process to ensure that the content of the information materials was accurate. Interviews were transcribed literally and analysed using qualitative thematic analysis, focusing on implications for information development. Notes, assignments and materials from the participatory design sessions were summarized and main themes were identified. Results: Women in both interviews and design sessions were positive about risk-based BC screening, especially because personal risk factors would be taken into account. However, they emphasized that the rationale of risk-based screening and classification into a risk category should be clearly stated and visualized, especially for higher- and lower-risk categories (which may cause anxiety or feelings of unfairness due to a lower screening frequency). Women wanted to know their personal risk, preferably visualized in an icon array, and wanted advice on risk reduction and breast self-examination. However, most risk factors were considered modifiable by women, and the risk factor breast density was not known, implying that information should emphasize that BC risk depends on multiple factors, including breast density. Conclusions: The information materials, including risk visualizations of both quantitative and qualitative information, developed from a Human-Centered Design perspective and a mental model approach, were positively evaluated by the target group.","Breast cancer; Cancer screening; Educational material; Informed decision making; Participatory design; Risk communication; Risk visualizations; Risk-based screening","en","journal article","","","","","","","","","","","Applied Ergonomics and Design","","",""
"uuid:d543b40b-4f8c-4838-b2be-9c88109ec6d3","http://resolver.tudelft.nl/uuid:d543b40b-4f8c-4838-b2be-9c88109ec6d3","Exploring a geodesign approach for circular economy transition of cities and regions: Three European cases","Furlan, C. (TU Delft Environmental Technology and Design; BOKU-University of Natural Resources and Life Sciences); Mazzarella, C. (TU Delft Real Estate Management); Arlati, Alessandro (Universität Hamburg); Arciniegas, Gustavo (Geo-Col GIS); Obersteg, Andreas (Geo-Col GIS); Wandl, Alex (TU Delft Environmental Technology and Design); Cerreta, Maria (Università degli Studi di Napoli Federico II)","","2024","Transitioning towards a circular built environment and turning waste into resources have become one of the new sustainability paradigms today. However, a circular transition can be considered a ‘wicked problem’. The multiple dimensions and scales of the circular transition and its substantial spatial implications fit well into the planning approach of Geodesign. The Horizon 2020 funded project “Resource Management in the periurban Areas - Going beyond Urban Metabolism (REPAiR)” implemented an innovative Geodesign approach. Moreover, it explored its capability to support spatial decision-making processes for the circular economy transition of the built environment within urban planning practices. This article aims to understand to what extent a process of Geodesign, which is conducted with the support of a digital tool and a Living Lab approach, can support the creation of localised circular economy strategies and foster the circular economy transition in cities and territories. The analysis explores and compares the results of three European cases -Amsterdam, Hamburg and Naples. It considers the kind of data input required to run the process in every phase, the stakeholders involved and their typology, the specific urban or territorial, planning and governance scales of analysis, and the final output definition after the Geodesign process implementation. The approach outputs constitute a decision support system for easing negotiations between local actors regarding the circularity strategies to implement. The findings reveal an intertwinement between different forms of knowledge included in the process, ranging from sustainability to governance and design, and the actors engaged in planning a circularity transition spatially. However, even using similar starting data, the local information and the starting conditions strongly influence the process and the types of strategies elaborated in each case.","","en","journal article","","","","","","","","","","","Environmental Technology and Design","","",""
"uuid:7241a1c8-890a-433f-9884-4b96b2f2b3ed","http://resolver.tudelft.nl/uuid:7241a1c8-890a-433f-9884-4b96b2f2b3ed","Spatial optimization of circular timber hubs","Tsui, T.P.Y. (TU Delft Environmental & Climate Design); Venverloo, T. (Massachusetts Institute of Technology); Benson, Tom (Massachusetts Institute of Technology); Duarte, Fábio (Massachusetts Institute of Technology)","","2024","In the European Union, construction is responsible for 36% of CO2 emissions and 40% energy consumption. The reuse of construction materials has been receiving increasing attention, including regulations established by the European Union, and cities establishing goals to reuse construction materials. This is the case for Amsterdam, which established the goal of reusing 50% of construction materials in new construction by 2030. Part of the challenge of reuse of construction materials in urban areas is to optimize the waste-to-resource loops: finding the optimal scale and location for circular construction hubs—facilities that collect, store, and redistribute construction waste as secondary construction materials. In this paper, we use the supply and demand of timber construction materials in Amsterdam as a case study to find the optimal scale and location for construction hubs. We used the spatial simulated annealing algorithm as an optimization method for balancing the trade-off between small and large-scale hubs, using cost-effectiveness to compare potential locations and identify the optimal solution. We found that the optimal number of hubs for our study area is 29, with an average service radius of 3 km. This study has implications for policymakers, urban planners, and companies seeking to implement circular economy principles.","","en","journal article","","","","","","","","","","","Environmental & Climate Design","","",""
"uuid:c0e15914-6682-4415-a6b6-068bdfcf954e","http://resolver.tudelft.nl/uuid:c0e15914-6682-4415-a6b6-068bdfcf954e","Advancements and insights in thermal and water management of proton exchange membrane fuel cells: Challenges and prospects","Zhang, Zhenya (Zhengzhou University); Mao, Jia (Zhengzhou University); Liu, Zhengxuan (TU Delft Design & Construction Management)","","2024","In response to the growing global demand for clean and sustainable energy solutions, proton exchange membrane fuel cells (PEMFCs) have emerged as vital components in diverse decarbonization strategies. Despite their increasing importance, a comprehensive synthesis of recent advancements, challenges, and future prospects in thermal and water management within this domain remains notably scarce. This paper aims to bridge this gap by conducting a meticulous literature review focused on thermal and water management in PEMFCs. Primarily, this study encapsulates the underlying mechanisms governing thermal and water generation in PEMFCs, intricately analyzing thermal and water generation analyses. Secondly, a multifaceted exploration of thermal and water transfer mechanisms, alongside their pivotal influencing factors, is presented. Furthermore, the discourse delves into sophisticated strategies for refining water and thermal management in PEMFCs. As well as delving into the complexities of high-power heat dissipation and water balance, especially water management for cold start and high temperature operating conditions. The culmination of this investigation yields valuable insights into the intricate dynamics of thermal and water management within PEMFCs, thereby culminating in forward-looking recommendations for future research trajectories. These findings not only offer scholars a vantage point to discern emerging research frontiers and trends but also extend theoretical precepts and reference points for technology innovators and product developers.","Clean energy; High-power heat dissipation; Proton exchange membrane fuel cells (PEMFCs); Thermal management; Water management","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:ddddd8d4-ea74-4c70-9407-1b6c3953208e","http://resolver.tudelft.nl/uuid:ddddd8d4-ea74-4c70-9407-1b6c3953208e","Refining the survey model of the LADM ISO 19152–2: Land registration","Kalogianni, E. (TU Delft Digital Technologies); Dimopoulou, Efi (National Technical University of Athens); Gruler, Hans-Christoph (Leica Geosystems); Stubkjær, Erik (Aalborg University); Morales, Javier (International Institute for Geo-Information Science and Earth Observation (ITC)); Lemmen, Christiaan (International Institute for Geo-Information Science and Earth Observation (ITC)); van Oosterom, P.J.M. (TU Delft Digital Technologies)","","2024","Cadastral surveying involves the delineation of property boundaries and the extent and documentation of easements and restrictions (imposed by private or public law), forming the foundation for Land Administration (LA). Survey models and processes constitute vital parts of Cadastres and Land Administration Systems (LASs). However, these models are often inadequately documented and lack standardization in practice. To address the global diversity and complexity of legal and administrative challenges in LA, standardization efforts have yielded the ISO 19152:2012 (ISO, 2012) Land Administration Domain Model (LADM), the Global Land Tool Network's (GLTN) Social Tenure Domain Model (STDM), and the OGC LandInfra/InfraGML standard. The current edition of the LADM focuses on standardised conceptual modelling of LA-related information, including a dedicated sub-package for Spatial and Surveying representation. As part of the ongoing LADM revision, a refined survey model is being developed to support a broad range of surveying and data acquisition approaches and levels of accuracy. Recognizing that surveying technology is not bound by national practices and regulations, this paper focuses specifically on the surveying aspect of LADM. It illustrates that the proposed refined survey model is applicable not only to conventional real property formation but also to participatory land rights recordation processes. The approach adopted in this research is technology-neutral, accommodating the ongoing evolution of surveying technology. It offers support for a broad range of surveying and data acquisition approaches, with varying levels of accuracy. As the demand for high-precision positioning has been persistent within the land mapping and surveying community, particularly since the initial adoption of GPS, aiming to achieve centimetre-level accuracies (initially confined to local services), the paper addresses the fundamental principles of the High Accuracy Service (HAS) concept within the proposed model. The main results presented in this paper are the conceptual model of the refined survey model of LADM Edition II (ISO19152–2), as well as an abstract, reference, cadastral surveying workflow following the principles of the proposed model.","Cadastral surveying workflow; Interoperability; LADM; Land administration; Standards; Survey model","en","journal article","","","","","","","","","","","Digital Technologies","","",""
"uuid:213602b7-9f32-496b-b262-586560ff46a6","http://resolver.tudelft.nl/uuid:213602b7-9f32-496b-b262-586560ff46a6","A market for trading forecasts: A wagering mechanism","Raja, A.A. (TU Delft Team Sergio Grammatico); Pinson, Pierre (Imperial College London; Technical University of Denmark); Kazempour, Jalal (Technical University of Denmark); Grammatico, S. (TU Delft Team Sergio Grammatico; TU Delft Team Bart De Schutter)","","2024","In many areas of industry and society, including energy, healthcare, and logistics, agents collect vast amounts of data that are deemed proprietary. These data owners extract predictive information of varying quality and relevance from data depending on quantity, inherent information content, and their own technical expertise. Aggregating these data and heterogeneous predictive skills, which are distributed in terms of ownership, can result in a higher collective value for a prediction task. In this paper, a platform for improving predictions via the implicit pooling of private information in return for possible remuneration is envisioned. Specifically, a wagering-based forecast elicitation market platform has been designed, in which a buyer intending to improve their forecasts posts a prediction task, and sellers respond to it with their forecast reports and wagers. This market delivers an aggregated forecast to the buyer (pre-event) and allocates a payoff to the sellers (post-event) for their contribution. A payoff mechanism is proposed and it is proven that it satisfies several desirable economic properties, including those specific to electronic platforms. Furthermore, the properties of the forecast aggregation operator and scoring rules are discussed in order to emphasize their effect on the sellers’ payoff. Finally, numerical examples are provided in order to illustrate the structure and properties of the proposed market platform.","Elicitation of probabilities; Mechanism design; Predictive distribution; Scoring rules; Value of forecast; Wagering mechanism","en","journal article","","","","","","","","","","","Team Sergio Grammatico","","",""
"uuid:78640ecc-ad2a-490c-8783-912f4047d488","http://resolver.tudelft.nl/uuid:78640ecc-ad2a-490c-8783-912f4047d488","Analysis of the Boundary Layer on a Highly Flexible Wing Based on Infrared Thermography Measurements","Mertens, C. (TU Delft Aerodynamics); Grille Guerra, A. (TU Delft Aerodynamics); van Oudheusden, B.W. (TU Delft Aerodynamics); Fehrs, Michael (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Ritter, Markus R. (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR))","","2024","The effects of the wing skin distortion on the boundary layer of a highly flexible wing are analyzed in a wind tunnel experiment using infrared thermography measurements. Considerable differences in the boundary layer flow are observed when comparing the sections of the wing near the ribs, where the design shape of the wing is preserved, and in between the ribs. At the spanwise locations between the ribs, the sectional wing shape distorts and triggers boundary layer transition close to the leading edge. The differences between the design behavior of the wing and the experimental results of the boundary layer analysis demonstrate the need for considering the skin deformation and its effects on the boundary layer flow when designing highly flexible wings.","differential infrared thermography; laminar separation bubble; Pazy wing; wind tunnel test","en","book chapter","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-01","","","Aerodynamics","","",""
"uuid:666d9f4f-fdf5-4d48-870c-d0b3191b7090","http://resolver.tudelft.nl/uuid:666d9f4f-fdf5-4d48-870c-d0b3191b7090","Parametric investigation of railway fastenings into the formation and mitigation of short pitch corrugation","Zhang, P. (TU Delft Railway Engineering); Li, S. (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","","2024","Short pitch corrugation has been a problem for railways worldwide over one century. In this paper, a parametric investigation of fastenings is conducted to understand the corrugation formation mechanism and gain insights into corrugation mitigation. A three-dimensional finite element vehicle–track dynamic interaction model is employed, which considers the coupling between the structural dynamics and the contact mechanics, while the damage mechanism is assumed to be differential wear. Various fastening models with different configurations, boundary conditions, and parameters of stiffness and damping are built up and analysed. These models may represent different service stages of fastenings in the field. Besides, the effect of train speeds on corrugation features is studied. The results indicate: (1) Fastening parameters and modelling play an important role in corrugation formation. (2) The fastening longitudinal constraint to the rail is the major factor that determines the corrugation formation. The fastening vertical and lateral constraints influence corrugation features in terms of spatial distribution and wavelength components. (3) The strengthening of fastening constraints in the longitudinal dimension helps to mitigate corrugation. Meanwhile, the inner fastening constraint in the lateral direction is necessary for corrugation alleviation. (4) The increase in fastening longitudinal stiffness and damping can reduce the vibration amplitudes of longitudinal compression modes and thus reduce the track corrugation propensity. The simulation in this work can well explain the field corrugation in terms of the occurrence possibility and major wavelength components. It can also explain the field data with respect to the small variation between the corrugation wavelength and train speed, which is caused by frequency selection and jump between rail longitudinal compression modes.","Corrugation formation and mitigation; Fastening modelling and parameters; Finite element vehicle–track interaction model; Rail longitudinal compression modes; Short pitch corrugation","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:f7731f60-10c2-4f82-b34b-e41ba95ffacb","http://resolver.tudelft.nl/uuid:f7731f60-10c2-4f82-b34b-e41ba95ffacb","Downscaling MODIS NDSI to Sentinel-2 fractional snow cover by random forest regression","Kollert, Andreas (University of Innsbruck); Mayr, Andreas (University of Innsbruck); Dullinger, Stefan (University of Vienna); Hülber, Karl (University of Vienna); Moser, Dietmar (University of Vienna); Lhermitte, S.L.M. (TU Delft Mathematical Geodesy and Positioning; Katholieke Universiteit Leuven); Gascoin, Simon (Université de Toulouse); Rutzinger, Martin (University of Innsbruck)","","2024","Imagery acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS) provides a global archive of dailyNormalized Difference Snow Index (NDSI) at 500 m nominal resolution since the year 2000. While Sentinel-2 (S2) NDSI provides an increased spatial resolution of 20 m since the year 2015, the temporal resolution amounts to only 5 days and thus lacks the high temporal resolution of MODIS. Efforts to combine NDSI datasets for an increased temporal and spatial resolution have so far focused on the deriving binary snow cover maps or combining data from other sensors. In contrast, we produce fine scale (20 m) fractional snow cover (FSC) by downscaling MODIS NDSI to S2 resolution. Random forest regression predicts S2 NDSI based on dynamic features (MODIS NDSI, day-of-year) and static, topographic features for an alpine study site. Subsequently, FSC is derived from S2 NDSI. Cross-validation results in R2 of 0.795 and RMSE of 0.155 for FSC and outperforms common resampling methods. Multi-annual S2 NDSI metrics are able to slightly improve model accuracy. Our results suggest that combining topographical data and low-resolution NDSI allows to produce daily, high-resolution S2 NDSI and FSC and improve fine scale characterization of snow cover dynamics in mountain landscapes.","downscaling; Fractional Snow Cover (FSC); machine learning; MODIS; Normalized Difference Snow Index (NDSI); Sentinel-2 (S2)","en","journal article","","","","","","","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:a9aefce1-1037-430c-ae99-13c1d2aedc9d","http://resolver.tudelft.nl/uuid:a9aefce1-1037-430c-ae99-13c1d2aedc9d","Introducing a new method to assess the benefits of resources recovered from wastewater to the natural environment","Bhambhani, A. (TU Delft Sanitary Engineering); Jovanovic, O. (TU Delft Sanitary Engineering); van Nieuwenhuijzen, Arjen (Wageningen University & Research; Witteveen+Bos); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet); Kapelan, Z. (TU Delft Sanitary Engineering)","","2024","Resources recovery can improve the economic efficiency and reduce the negative environmental impacts of municipal wastewater treatment plants (MWWTP). The recovered resources can also actively benefit the natural environment enabling a reciprocal relationship between human society and nature. Focusing on these benefits can reveal new resources recovery opportunities. Moreover, for certain environmental impact categories such as emissions of reactive nitrogen, mere damage reduction is insufficient because these emissions are already beyond planetary limits. However, quantitative methods to assess nature benefits are lacking. A new method is developed to calculate the potential nature benefits in three categories: Freshwater restoration, biomass assimilation of nutrients, and soil organic matter sequestration and it is demonstrated on a real-life MWWTP. Focusing on resources recovery helps to purify the wastewater sufficiently for discharge and to benefit the natural environment. Treated wastewater discharge into a river can support freshwater restoration depending on the effluent quality. High quality is achieved by the sufficient removal of the nutrients and organic matter and discharging into a high-flow stream. The recovery of nutrients helps to close the nutrient cycle through biomass assimilation. To maximize this benefit, the nutrient recovery efficiency from the MWWTP must be maximized. But, increasing the nutrient uptake efficiency in agriculture is also crucial, especially for nitrogen. The wastewater sludge products can be applied to soil to sequester organic matter and the products with low volatile solids should be preferred. The development of the new method is a start to recognizing and assessing the potentially positive role of humans in nature.","Reciprocity; Nature benefits; Resources recovery; Wastewater treatment","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:ef4d2052-bb63-406e-a9b5-dff3a281567d","http://resolver.tudelft.nl/uuid:ef4d2052-bb63-406e-a9b5-dff3a281567d","Development of a hazard risk map for assessing pedestrian risk in urban flash floods: A case study in Cúcuta, Colombia","Corzo Perez, Gerald Augusto (IHE Delft Institute for Water Education); Sanchez Tapiero, Diego Ivan (University of Pamplona); Contreras Martínez, Manuel Antonio (University of Pamplona); Zevenbergen, C. (TU Delft Urban Design)","","2024","The rapid growth of impervious areas in urban basins worldwide has increased the number of impermeable surfaces in cities, leading to severe flooding and significant economic losses for civilians. This trend highlights the urgent need for methodologies that assess flood hazards and specifically address the direct impact on pedestrians, which is often overlooked in traditional flood hazard analyses. This study aims to evaluate a methodology for assessing the risk to pedestrians from hydrodynamic forces during urban floods, with a specific focus on Cúcuta, Colombia. The methodology couples research outcomes from other studies on the impact of floodwaters on individuals of different ages and sizes with 1D/2D hydrological modeling. Advanced computational algorithms for image recognition were used to measure water levels at 5-s intervals on November 6, 2020, using drones for digital elevation model data collection. In Cúcuta, where flood risk is high and drainage infrastructure is limited, the PCSWMM (Computer-based Urban Stormwater Management Model) was calibrated and validated to simulate extreme flood events. The model incorporated urban infrastructure details and geomorphological parameters of Cúcuta's urban basin. Four return periods (5, 10, 50, 100), with extreme rainfall of 3 h, were used to estimate the variability of the risk map. The output of the model was analyzed, and an integrated and time-varying comparison of the results was done. Results show that the regions of high-water depth and high velocity could vary significantly along the duration of the different extreme events. Also, from 5 to 100 years return period, the percentage of area at risk increased from 9.6% to 16.6%. The pedestrian sensitivity appears much higher than the increase in velocities or water depth individually. This study identified medium to high-risk locations, which are dynamic in time. We can conclude dynamics are spatiotemporal, and the added information layer of pedestrians brings vulnerability information that is also dynamic. Areas of immediate concern in Cúcuta can enhance pedestrian safety during flash flood events. The spatiotemporal variation of patterns requires further studies to map trajectories and sequences that machine learning models could capture.","hazard and risk mapping; pedestrian risk; urban flood","en","journal article","","","","","","","","","","","Urban Design","","",""
"uuid:caa942c6-2bba-4b57-81d3-d29c6dcabf9f","http://resolver.tudelft.nl/uuid:caa942c6-2bba-4b57-81d3-d29c6dcabf9f","Explainable artificial intelligence for intrusion detection in IoT networks: A deep learning based approach","Sharma, Bhawana (Manipal University Jaipur); Sharma, Lokesh (Manipal University Jaipur); Lal, C. (TU Delft Cyber Security); Roy, Satyabrata (Manipal University Jaipur)","","2024","The Internet of Things (IoT) is currently seeing tremendous growth due to new technologies and big data. Research in the field of IoT security is an emerging topic. IoT networks are becoming more vulnerable to new assaults as a result of the growth in devices and the production of massive data. In order to recognize the attacks, an intrusion detection system is required. In this work, we suggested a Deep Learning (DL) model for intrusion detection to categorize various attacks in the dataset. We used a filter-based approach to pick out the most important aspects and limit the number of features, and we built two different deep-learning models for intrusion detection. For model training and testing, we used two publicly accessible datasets, NSL-KDD and UNSW-NB 15. First, we applied the dataset on the Deep neural network (DNN) model and then the same dataset on Convolution Neural Network (CNN) model. For both datasets, the DL model had a better accuracy rate. Because DL models are opaque and challenging to comprehend, we applied the idea of explainable Artificial Intelligence (AI) to provide a model explanation. To increase confidence in the DNN model, we applied the explainable AI (XAI) Local Interpretable Model-agnostic Explanations (LIME ) method, and for better understanding, we also applied Shapley Additive Explanations (SHAP).","Convolution neural network; Deep neural network; DL; Intrusion detection system; Local interpretable model-agnostic explanations; Shapley additive explanations; XAI","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-25","","","Cyber Security","","",""
"uuid:27c70dcf-402f-4073-ac9c-ac48abd08de4","http://resolver.tudelft.nl/uuid:27c70dcf-402f-4073-ac9c-ac48abd08de4","Generation of Secondary Space Debris Risks from Net Capturing in Active Space Debris Removal Missions","Cuadrat-Grzybowski, M. (TU Delft Astrodynamics & Space Missions); Gill, E.K.A. (TU Delft Space Systems Egineering)","","2024","Mitigation strategies to eliminate existing space debris, such as with Active Space Debris Removal (ASDR) missions, have become increasingly important. Among the considered ASDR approaches, one involves using a net as a capturing mechanism. A fundamental requirement for any ASDR mission is that the capture process itself should not give rise to new space debris. However, in simulations of net capturing, the potential for structural breaking is often overlooked. A discrete Multi-Spring-Damper net model was employed to simulate the impact of a 30 m × 30 m net travelling at 20 m/s onto an ESA Envisat mock-up. The Envisat was modelled as a two-rigid-body system comprised of the main body and a large solar array with a hinge connection. The analysis revealed that more than two significant substructures had a notable likelihood of breaking, prompting the recommendation of limiting the impacting velocity. The generation of secondary space debris indicates that net capturing is riskier than previously assumed in the literature.","active debris removal; net capturing; structural breaking; secondary space debris generation","en","journal article","","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:8fab9c16-56f1-4068-9631-a2812c9eadd7","http://resolver.tudelft.nl/uuid:8fab9c16-56f1-4068-9631-a2812c9eadd7","Land-free bioenergy from circular agroecology: a diverse option space and trade-offs","Wu, F. (TU Delft Energie and Industrie; ETH Zürich); Pfenninger, Stefan (TU Delft Energie and Industrie); Muller, Adrian (Research Institute of Organic Agriculture FiBL)","","2024","Bioenergy from energy crops is a source of negative emissions and carbon-neutral fuels in many 1.5/2 ∘C IPCC pathways. This may compete with other land uses. In contrast, ancillary biomass like by-products and waste is not primarily grown for energy and thus without land/food/feed competition. Here, we examine the availability and environmental impacts of ancillary bioenergy from agricultural sources under 190 circular agroecological strategies using the global food-system model SOLm for the year 2050. We find that there is a diverse option space for the future food and energy system to meet both global warming targets (1.5 ∘C) and food system sustainability (medium to highly organic) – a similar range of ancillary bioenergy global potential (55–65 EJ)from very different food systems (50%–75% organic agriculture and various levels of waste and concentrate feeding reduction). We find three trade-offs between food system sustainability and ancillary bioenergy provision. First, there is a clear trade-off between nutrient recycling and negative emissions potential. 1.4–2.6 GTCO2eq of negative emissions supplied through ancillary bioenergy with carbon capture and storage comes at the cost of nutrient deficits and resulting incompatibility with even a medium degree of organic farming. Second, reducing feed from croplands increases the ancillary bioenergy production with low shares of organic agriculture and reduces it for high shares. Third, food waste reduction reduces ancillary bioenergy provision. Hence, the sustainable transformation of the food system towards a less animal-based diet and waste reduction may conflict with a higher ancillary bioenergy provision, especially when the organic share is high as well. The policy implication of our results is that ancillary bioenergy can provide a similar range of future bioenergy as foreseen in IPCC AR6 illustrative pathways (±10% ) without additional land use or compromising food availability. However, higher ancillary bioenergy provision or additional negative emissions compete with food system sustainability; hence, we recommend policymakers consider aligning energy system planning with the compatibility of sustainable food systems simultaneously.","","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:443b3cfc-7414-4d35-89c4-baef07af62b8","http://resolver.tudelft.nl/uuid:443b3cfc-7414-4d35-89c4-baef07af62b8","Three-dimensional surface strain sensor based on PDMS/LIG composite film with adjustable electromechanical performance","Yang, Huiru (Harbin Institute of Technology; Southern University of Science and Technology); Huang, Qianming (Harbin Institute of Technology; Southern University of Science and Technology); Wang, S. (TU Delft Bio-Electronics); Zong, Qihang (Southern University of Science and Technology); Tan, C. (TU Delft Electronic Components, Technology and Materials); Ye, H. (Southern University of Science and Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2024","Flexible strain sensors play a crucial role in health monitoring, smart wearable devices, and human–machine interaction. Three-dimensional surface evaluation methods for strain sensors offer advantages by being closer to actual strain, featuring a larger working range, and being more suitable for multidirectional strain. In this study, a three-dimensional (3D) surface strain sensor based on polydimethylsiloxane/laser-induced graphene (PDMS/LIG) composite films has been developed. The electromechanical properties of this sensor, encompassing 3D strain range and sensitivity, can be adjusted by manipulating laser parameters and LIG patterns. The key to attaining these specific characteristics lies in the intentional design of crack types and orientations on the sensor's surface. Remarkably, the line-vertical (LV) sensor exhibits outstanding sensitivity with a GF of 211.3. The line-parallel (LP) sensor achieves a GF of 115.1. Additionally, it demonstrates a stretching range of 25% and maintains stable performance over an extensive number of strain/release test cycles (more than 3000 cycles). With these advantages, the 3D strain sensor can not only be applied in human activity monitoring but also monitoring pressure within microchannels in microfluidic chips, suggesting promising applications in the health and medical fields.","3D surface sensing; Adjustable electromechanical performance; PDMS/LIG composite; Strain sensor","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2025-01-01","","","Bio-Electronics","","",""
"uuid:9dd05d41-e515-4b6b-a1e5-f18fc06b7023","http://resolver.tudelft.nl/uuid:9dd05d41-e515-4b6b-a1e5-f18fc06b7023","High-Pressure oxidative coupling of methane on alkali metal catalyst – Microkinetic analysis and operando thermal visualization","Yu, Yuhang (University of Tokyo); Obata, Keisuke (University of Tokyo); Movick, William J. (University of Tokyo); Yoshida, Shintaro (University of Tokyo); Palomo Jiménez, J. (TU Delft ChemE/Catalysis Engineering); Lundin, Sean Thomas B. (National Institute of Advanced Industrial Science and Technology (AIST)); Urakawa, A. (TU Delft ChemE/Catalysis Engineering); Sarathy, S. Mani (King Abdullah University of Science and Technology); Takanabe, Kazuhiro (University of Tokyo; Japan Science and Technology Agency)","","2024","To introduce promotional H2O effects for both CH4 rate and C2 selectivity, the OH radical formation, catalyzed through H2O activation with O2 surface species, was critical for modeling selective Mn-K2WO4/SiO2 catalysts. Based on our reported experimental evidence, which demonstrates the formation of H2O2 through surface alkali peroxide intermediate, the elementary reactions that account for the OH-mediated pathway were added into the microkinetic model. The advanced model adeptly replicated the promotional H2O effects on both OCM rate and selectivity. The data from a low-pressure microkinetic study were treated isothermally, and extended for near-industrially relevant pressures up to 901 kPa. Thermal visualization using an infrared camera found substantial temperature increases at undiluted high-pressure conditions which caused C2 selectivity to drop significantly. When the furnace temperatures were decreased after ignition, side reactions after O2 depletion (e.g., hydrocarbon reforming) were suppressed, obtaining 13.7 (11.8) % yields at 19.9 % CH4 conversion with 68.6 (59.1) % selectivities for C2-4 (C2) at 901 kPa. The temperature was found to be the determining factor of C2 yield which was perturbed by varying space velocity or CH4/O2 ratios. The optimum temperature for high-pressure conditions was predicted as 885 °C at 901 kPa. The study provides mechanistic and industrially relevant understandings for further OCM catalyst design and system application.","High pressure; Microkinetic analysis; OCM mechanisms; OH-mediated pathway; Operando thermal visualization","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:25a4b40e-a832-4acf-b180-552db6eab78e","http://resolver.tudelft.nl/uuid:25a4b40e-a832-4acf-b180-552db6eab78e","BIM-LADM Amalgamation - A Review","Zamzuri, A. (Universiti Teknologi Malaysia); Abdul Rahman, A. (Universiti Teknologi Malaysia); Hassan, M.I. (Universiti Teknologi Malaysia); van Oosterom, P.J.M. (TU Delft Digital Technologies)","","2024","This paper discussed two International Organization for Standardization (ISO) standards, namely, ISO 19152 – Land Administration Domain Model (LADM) and ISO 16739 – Industry Foundation Classes (IFC), to identify three-dimensional (3D) multi-floor building rights. These days, it is challenging to characterize all multifunctional structures due to the increase in complex buildings. High-rise building land and property information management is recommended through building information modeling (BIM). Countries like the Netherlands, Australia, and Turkey have considered adopting BIM for their land administration. A land administration standard, such as LADM, offers better legal and physical representation in identifying the rights, restrictions, and responsibilities (RRRs) of the spatial units and stakeholders. However, LADM falls short in representing all building elements, such as semantic information and invisible functional spaces. Hence, this paper reviews incorporating additional information from BIM to create a comprehensive three-dimensional building representation including legal information from LADM. Issues and challenges also being highlighted with some recommendations for possible future works.","LADM; BIM/IFC; land administration; multi-floor building; RRRs","en","journal article","","","","","","","","","","","Digital Technologies","","",""
"uuid:444d976e-670b-4635-a111-8e4665991f97","http://resolver.tudelft.nl/uuid:444d976e-670b-4635-a111-8e4665991f97","Recovery from the pandemic: Planning the reterritorialisation of agricultural activities","Liu, Tianzhu (University of Bern); Korthals Altes, W.K. (TU Delft Urban Development Management); Wallet, Frédéric (INRAE center Occitanie-Toulouse); Melot, Romain (INRAE - Campus Agro Paris-Saclay)","Andres, Lauren (editor); Bryson, John R. (editor); Ersoy, Aksel (editor); Reardon, Louise (editor)","2024","This chapter discusses planning the reterritorialisation of agricultural activities as an avenue of the Covid-19 pandemic recovery. Reterritorialisation indicates local food being targeted to local inhabitants instead of the global market. We argue that the pandemic has accelerated the reterritorialisation process. Supply chain actors actively responded to the local market, local agrifood sector labour was revalued, the rural-urban linkage was rebuilt along with the lifestyle change, and public political awareness was raised in engaging local agrifood issues. We propose planning the reterritorialisation of agriculture as a solution to perpetuating local agrifood activities and recovering from the pandemic. We discuss planning strategies from perspectives of access to land, the transition of farming practices, and structuring local supply chains. We conclude with research agenda drawn from the challenges faced by the coexistence of local and global food systems, the policy coherence and the juxtaposed complex issues like climate change and geopolitical conflicts.","access to land; covid-19; food planning; local food system; short food supply chain; spatial planning","en","book chapter","Edward Elgar Publishing","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-12","","","Urban Development Management","","",""
"uuid:69a47953-3354-4bee-866a-c43cf3cd4154","http://resolver.tudelft.nl/uuid:69a47953-3354-4bee-866a-c43cf3cd4154","A Review of Climate and Resident-Oriented Renovation Processes: A Framework for Just Decision Support Systems","Ricci, Diletta (TU Delft Design & Construction Management); Konstantinou, T. (TU Delft Architectural Technology); Visscher, H.J. (TU Delft Design & Construction Management)","Littlewood, John R. (editor); Jain, Lakhmi (editor); Howlett, Robert J. (editor)","2024","The renovation of existing buildings is widely recognized as a powerful strategy for reducing emissions and land use. However, when it comes to residential buildings, the socio-technical challenges are particularly complex. The necessity and urgency of increasing energy efficiency often lead to retrofit processes that overlook residents’ needs and fail to consider the impact of renovation techniques on their lives. This study conducts a systematic and interdisciplinary literature review to explore how and to what extent social aspects, particularly residents and their needs, are considered in building renovations. An analysis of 40 studies from the Web of Science and Scopus databases is presented. The holistic overview focuses on two interrelated aspects: the orientation of decision-making processes towards residents and social components of multi-stakeholder involvement, and the relationship and interaction between design choices and residents. By doing so, the review enables a collection of meaningful and heterogeneous criteria for process management and retrofit solutions selection. Recognizing the existing gaps in the literature and clarifying relevant criteria, this review can help identify areas that require further research and intervention.","Renovation processes; End-users; Decision-making; Technology adoption; Systematic review","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-07","","","Design & Construction Management","","",""
"uuid:39c22eb7-e3d5-49c2-b138-07cad2fde29e","http://resolver.tudelft.nl/uuid:39c22eb7-e3d5-49c2-b138-07cad2fde29e","Solvation Shifts the Band-Edge Position of Colloidal Quantum Dots by Nearly 1 eV","Vogel, Y.B. (TU Delft ChemE/Opto-electronic Materials); Pham, Le Nhan (Flinders University of South Australia); Stam, M. (TU Delft ChemE/Opto-electronic Materials); Ubbink, R.F. (TU Delft ChemE/Opto-electronic Materials); Coote, Michelle L. (Flinders University of South Australia); Houtepen, A.J. (TU Delft ChemE/Opto-electronic Materials)","","2024","The optoelectronic properties of colloidal quantum dots (cQDs) depend critically on the absolute energy of the conduction and valence band edges. It is well known these band-edge energies are sensitive to the ligands on the cQD surface, but it is much less clear how they depend on other experimental conditions, like solvation. Here, we experimentally determine the band-edge positions of thin films of PbS and ZnO cQDs via spectroelectrochemical measurements. To achieve this, we first carefully evaluate and optimize the electrochemical injection of electrons and holes into PbS cQDs. This results in electrochemically fully reversible electron injection with >8 electrons per PbS cQDs, allowing the quantitative determination of the conduction band energy for PbS cQDs with various diameters and surface compositions. Surprisingly, we find that the band-edge energies shift by nearly 1 eV in the presence of different solvents, a result that also holds true for ZnO cQDs. We argue that complexation and partial charge transfer between solvent and surface ions are responsible for this large effect of the solvent on the band-edge energy. The trend in the energy shift matches the results of density functional theory (DFT) calculations in explicit solvents and scales with the energy of complexation between surface cations and solvents. As a first approximation, the solvent Lewis basicity can be used as a good descriptor to predict the shift of the conduction and valence band edges of solvated cQDs.","","en","journal article","","","","","","","","","","","ChemE/Opto-electronic Materials","","",""
"uuid:b0950925-9d33-40a6-8d5d-8b2dc1e060a2","http://resolver.tudelft.nl/uuid:b0950925-9d33-40a6-8d5d-8b2dc1e060a2","Comparison of Compact and Decentralized Urban Development Pathways for Flood Mitigation in Urbanizing Deltas: Guangzhou in the Pearl River Delta as a Case Study","Lin, Weibin (Central South University China; South China University of Technology); Sun, Yimin (South China University of Technology); Nijhuis, S. (TU Delft Landscape Architecture)","","2024","Floods are common and inevitable natural disasters. Achieve Sustainable Development Goal (SDG) 11.5 is a critical challenge for coastal cities, especially those in deltaic lowlands such as in the case of Guangzhou, China. Regarding the spatial planning and design of such urban regions, it is crucial to study the impacts of flooding in compact or decentralized spatial development pathways. This reinforces the understanding of the relationship between strategic decisions for spatial planning and flood mitigation. However, the lack of a computer model to assess spatial evolution paths is a significant limitation. The non-dominated Sorting Genetic Algorithm II (NSGA-II) explores the possibility of a compact built-up land layout in 2030. The results showed that, concerning the 2030 decentralized scenario, the 2030 compact scenario presents a large increase in the integrated fitness function value from 0.618 to 0.771 (the increase is equivalent to 0.153 or about 24.75%). In addition, different development scenarios were constructed by setting different target weights. Compared to the decentralized scenario results, the fitness function values of the optimization results of each scenario showed better results at different levels. They could also serve as a reference for other similar coastal areas to achieve SDG 11.5 by 2030.","spatial evolution path; Guangzhou estuary area; multi-objective optimization; flood disaster; SDG 11.5","en","journal article","","","","","","","","","","","Landscape Architecture","","",""
"uuid:b4840105-44cc-43a7-ae08-1424449bb2e8","http://resolver.tudelft.nl/uuid:b4840105-44cc-43a7-ae08-1424449bb2e8","Measuring Housing Inequality with the Value of Freedom in the Capability Approach: Proposal and Demonstration","Kimhur, Boram (TU Delft Urban Development Management)","","2024","An ongoing question in capability research is how to incorporate the value of freedom into the measurement of inequality. This article proposes an approach to answering this question in the housing domain and its operationalisation. The approach places an evaluation focus to the conditions constraining or expanding housing choices in the dimensions of opportunity, security, and ability. For operationalisation, the study designed a measurement of multidimensional housing disadvantages (MHDs) using the Alkire-Foster method and data from the Netherlands. Indicators include the entitlement to housing tenure options, vulnerability in housing cost payments, and ability to plan finance for housing. The measurement outcome demonstrates that the MHDs measurement can provide information on whose housing choices are more intensely constrained, thus having a lower capability for housing, and whose current housing situation is likely a result of coerced choices. The findings indicate that adults living with housemates or family (latent households), youths, and those with precarious jobs have a significantly lower capability for housing compared to other population groups. This article also compares the freedom-oriented measure of MHDs with functioning-oriented and other conventional measures and discusses its distinguishing properties. This comparison suggests a need to revisit current policy priorities in addressing housing inequality.","capability approach; freedom; inequality; multidimensional measurement; housing; capability for housing","en","journal article","","","","","","","","","","","Urban Development Management","","",""
"uuid:2abc58f2-56ec-4d5d-a70e-b4e46b9468fb","http://resolver.tudelft.nl/uuid:2abc58f2-56ec-4d5d-a70e-b4e46b9468fb","Incompatibility stress at inclined grain boundaries for cubic crystals under hydrostatic stress and uniaxial stress","Liu, K. (TU Delft Team Marcel Sluiter); Sluiter, M.H.F. (TU Delft Team Marcel Sluiter; Universiteit Gent)","","2024","In a material under stress, grain boundaries may give rise to stress discontinuities. The stress state at grain boundaries strongly affects microscopic processes, such as diffusion and segregation, as well as failure initiation, such as fatigue, creep, and corrosion. Here the general condition of incompatibility stress at grain boundaries is studied with a bicrystal model for linear elastic materials. In materials with cubic crystal structures, it is proven that hydrostatic stress does not lead to a stress discontinuity at grain boundaries. For bicrystals with inclined grain boundaries under uniaxial stress, the extreme values of the incompatibility stress as a function of the inclination angle are obtained by a simulated annealing method. A simple criterion is proposed to classify cubic materials into three groups. For cubic crystals with at most moderate anisotropy, the highest incompatibility stress occurs when the grain boundary plane is perpendicular to the uniaxial stress. For highly anisotropic materials, such as alkali metals and polymorphic high-temperature phases, the highest incompatibility stress occurs on grain boundaries with an inclination of about 47o.","Anisotropy; Grain boundary; Grain boundary inclination; Incompatibility stress; Stress concentration","en","journal article","","","","","","","","","","","Team Marcel Sluiter","","",""
"uuid:390be0c8-ea3d-4ed2-8c10-33176f18a87f","http://resolver.tudelft.nl/uuid:390be0c8-ea3d-4ed2-8c10-33176f18a87f","Magnetically tunable supercurrent in dilute magnetic topological insulator-based Josephson junctions","Mandal, Pankaj (University of Würzburg; Institute for Topological Insulators, Wurzburg); Mondal, Soumi (University of Würzburg; Institute for Topological Insulators, Wurzburg); Stehno, Martin P. (University of Würzburg; Institute for Topological Insulators, Wurzburg); Ilić, Stefan (Centro Mixto CSIC-UPV/EHU); Bergeret, F. Sebastian (Donostia International Physics Center; Centro Mixto CSIC-UPV/EHU); Klapwijk, T.M. (TU Delft QN/Afdelingsbureau; Kavli institute of nanoscience Delft); Gould, Charles (Universitat Wurzberg, Wurzberg; Institute for Topological Insulators, Wurzburg); Molenkamp, Laurens W. (University of Würzburg; Institute for Topological Insulators, Wurzburg)","","2024","A superconductor, when exposed to a spin-exchange field, can exhibit spatial modulation of its order parameter, commonly referred to as the Fulde–Ferrell–Larkin–Ovchinnikov state. Such a state can be induced by controlling the spin-splitting field in Josephson junction devices, allowing access to a wide range of the phase diagram. Here we demonstrate that a Fulde–Ferrell–Larkin–Ovchinnikov state can be induced in Josephson junctions based on the two-dimensional dilute magnetic topological insulator (Hg,Mn)Te. We do this by observing the dependence of the critical current on the magnetic field and temperature. The substitution of Mn dopants induces an enhanced Zeeman effect, which can be controlled with high precision by using a small external magnetic field. We observe multiple re-entrant behaviours of the critical current as a response to an in-plane magnetic field, which we assign to transitions between ground states with a phase shifted by π. This will enable the study of the Fulde–Ferrell–Larkin–Ovchinnikov state in much more accessible experimental conditions.","","en","journal article","","","","","","","","","","","QN/Afdelingsbureau","","",""
"uuid:e3d5468f-0364-4afe-a154-83e97dfa0c3c","http://resolver.tudelft.nl/uuid:e3d5468f-0364-4afe-a154-83e97dfa0c3c","Advanced Magnetocaloric Materials for Energy Conversion: Recent Progress, Opportunities, and Perspective","Zhang, F. (TU Delft RST/Fundamental Aspects of Materials and Energy; City University of Hong Kong); Miao, Xuefei (Nanjing University of Science and Technology); van Dijk, N.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); Brück, E.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); Ren, Yang (City University of Hong Kong)","","2024","Solid-state caloric effects as intrinsic thermal responses to different physical external stimuli (magnetic-, uniaxial stress-, pressure-, and electric-fields) can achieve a higher energy efficiency compared with traditional gas compression techniques. Among these effects, magnetocaloric energy conversion is regarded as the best available alternative and has been exploited extensively for promising application scenarios in the last decades. This review systematically introduces the magnetocaloric effect and its applications, and summarizes the corresponding representative magnetocaloric materials, as well as important progress in recent years. Specifically, the review focuses on some key understandings of the magnetocaloric effect by utilizing state-of-the-art technical tools such as synchrotron X-ray, neutron scattering, muon spin spectroscopy, positron annihilation spectroscopy, high magnetic fields, etc., and highlights their importance toward advanced materials design and development. An overview of the basic principles and applications of these advanced techniques on magnetocaloric materials is provided. Finally, the challenges and perspectives on further developments in this field are discussed. Further in-depth understanding and manufacturing technology advancement combined with fast-developed artificial intelligence and machine learning are expected to advance the magnetocaloric energy conversion technology closer to real applications.","advanced characterization; magnetocaloric energy conversion; magnetocaloric material; multimodal studies","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-29","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:01f81a92-d8ac-47ad-b8c6-131f2821a57e","http://resolver.tudelft.nl/uuid:01f81a92-d8ac-47ad-b8c6-131f2821a57e","Towards Structural and Aeroelastic Similarity in Scaled Wing Models: Development of an Aeroelastic Optimization Framework","Filippou, E. (TU Delft Group De Breuker); Kilimtzidis, Spyridon (University of Patras); Kotzakolios, Athanasios (University of Patras); Kostopoulos, Vassilis (University of Patras)","","2024","The pursuit of more efficient transport has led engineers to develop a wide variety of aircraft configurations with the aim of reducing fuel consumption and emissions. However, these innovative designs introduce significant aeroelastic couplings that can potentially lead to structural failure. Consequently, aeroelastic analysis and optimization have become an integral part of modern aircraft design. In addition, aeroelastic testing of scaled models is a critical phase in aircraft development, requiring the accurate prediction of aeroelastic behavior during scaled model construction to reduce costs and mitigate the risks associated with full-scale flight testing. Achieving a high degree of similarity between the stiffness, mass distribution and flow field characteristics of scaled models and their full-scale counterparts is of paramount importance. However, achieving similarity is not always straightforward due to the variety of configurations of modern lightweight aircraft, as identical geometry cannot always be directly scaled down. This configuration diversity has a direct impact on the aeroelastic response, necessitating the use of computational aeroelasticity tools and optimization algorithms. This paper presents the development of an aeroelastic scaling framework using multidisciplinary optimization. Specifically, a parametric Finite Element Model (FEM) of the wing is created, incorporating the parameterization of both thickness and geometry, primarily using shell elements. Aerodynamic loads are calculated using the Doublet Lattice Method (DLM) employing twist and camber correction factors, and aeroelastic coupling is established using infinite plate splines. The aeroelastic model is then integrated within an Ant Colony Optimization (ACO) algorithm to achieve static and dynamic similarity between the scaled model and the reference wing. A notable contribution of this work is the incorporation of internal geometry parameterization into the framework, increasing its versatility and effectiveness.","aeroelastic scaling; aeroelasticity; layout optimization; low-fidelity aerodynamics; sizing optimization; structural optimization","en","journal article","","","","","","","","","","","Group De Breuker","","",""
"uuid:0807aab6-06b6-4137-8a91-35e7ba0bc378","http://resolver.tudelft.nl/uuid:0807aab6-06b6-4137-8a91-35e7ba0bc378","Introduction to the Issue on Artificial Intelligence in the Public Sector: Risks and Benefits of AI for Governments","Mellouli, Sehl (Laval University); Janssen, M.F.W.H.A. (TU Delft Engineering, Systems and Services); Ojo, Adegboyega (Carleton University)","","2024","Artificial Intelligence (AI) is increasingly adopted by public sector organizations to provide better public services and to transform their internal processes. AI is now considered a key enabler for digital innovation and transformation in the public sector. However, AI is still relatively a new research area in the field of digital government. The term, AI, captures a wide range of technologies, techniques, and tools such as machine/deep learning, natural language processing, robotics, computer vision, and more recently Generative AI. While these AI technologies afford different applications and benefits in the gov- ernment context, they also create social, ethical, and legal challenges. These challenges require solutions combining both technical (e.g., data and algorithmic solutions to minimize bias) and institutional (e.g., governance structures and processes) mechanisms. The special issue is a collection of articles that contribute to a better understanding of the issues associated with AI deployment in different areas of government operations. They cover AI applications in the areas of emergency re- sponse, policy analysis, public bids, and citizen participation. The contributions also address the challenge of realizing a legal transparency regime for AI in government and the effect of AI in bureaucratic decision-making.","Artificial intelligence; benefits; e-government; risks","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-12","","Engineering, Systems and Services","","","",""
"uuid:2a66587b-f9a5-412a-8173-2b760244cdf8","http://resolver.tudelft.nl/uuid:2a66587b-f9a5-412a-8173-2b760244cdf8","Introducing the Azimuth Cutoff as an Independent Measure for Characterizing Sea-State Dynamics in SAR Altimetry","Altiparmaki, O. (TU Delft Astrodynamics & Space Missions); Amraoui, Samira (Collecte Localisation Satellites); Kleinherenbrink, M. (TU Delft Mathematical Geodesy and Positioning); Moreau, Thomas (Collecte Localisation Satellites); Maraldi, Claire (Centre National pour l’Etudes Spatiales); Visser, P.N.A.M. (TU Delft Space Engineering); Naeije, M.C. (TU Delft Astrodynamics & Space Missions)","","2024","This study presents the first azimuth cutoff analysis in Synthetic Aperture Radar (SAR) altimetry, aiming to assess its applicability in characterizing sea-state dynamics. In SAR imaging, the azimuth cutoff serves as a proxy for the shortest waves, in terms of wavelength, that can be detected by the satellite under certain wind and wave conditions. The magnitude of this parameter is closely related to the wave orbital velocity variance, a key parameter for characterizing wind-wave systems. We exploit wave modulations exhibited in the tail of fully-focused SAR waveforms and extract the azimuth cutoff from the radar signal through the analysis of its along-track autocorrelation function. We showcase the capability of Sentinel-6A in deriving these two parameters based on analyses in the spatial and wavenumber domains, accompanied by a discussion of the limitations. We use Level-1A high-resolution Sentinel-6A data from one repeat cycle (10 days) globally to verify our findings against wave modeled data. In the spatial domain analysis, the estimation of azimuth cutoff involves fitting a Gaussian function to the along-track autocorrelation function. Results reveal pronounced dependencies on wind speed and significant wave height, factors primarily determining the magnitude of the velocity variance. In extreme sea states, the parameters are underestimated by the altimeter, while in relatively calm sea states and in the presence of swells, a substantial overestimation trend is observed. We introduce an alternative approach to extract the azimuth cutoff by identifying the fall-off wavenumber in the wavenumber domain. Results indicate effective mitigation of swell-induced errors, with some additional sensitivity to extreme sea states compared to the spatial domain approach.","SAR altimetry; azimuth cutoff; wave orbital velocity; fully-focused SAR waveforms; sea state","en","journal article","","","","","","","","","","Space Engineering","Astrodynamics & Space Missions","","",""
"uuid:31d03aac-111d-4ce9-a3d5-cda9096c52c0","http://resolver.tudelft.nl/uuid:31d03aac-111d-4ce9-a3d5-cda9096c52c0","Non-intrusive temperature measurements for transient freezing in laminar internal flow using laser induced fluorescence","Kaaks, B.J. (TU Delft RST/Reactor Physics and Nuclear Materials); Couweleers, S.D. (TU Delft RST/Technici Pool); Lathouwers, D. (TU Delft RST/Reactor Physics and Nuclear Materials); Kloosterman, J.L. (TU Delft RST/Radiation, Science and Technology); Rohde, M. (TU Delft RST/Reactor Physics and Nuclear Materials)","","2024","This work presents two color LIF temperature measurements for the transient freezing in a square channel under laminar flow conditions. This is the first time non-intrusive temperature measurements were performed within the thermal boundary layer during the transient growth of an ice layer in internal flow. A combination of a local outlier factor algorithm and a smoothing operation was used to remove the top to bottom striations and reduce the other measurement noise. The temperature uncertainty in our measurements was between σ=0.3∘C and σ=0.5∘C. For the largest temperature difference between the bulk and the melting point of 14.6 °C, good results were obtained. As such, the current campaign demonstrates the potential of LIF as a non-intrusive temperature measurement technique for solid–liquid phase change experiments. However, some artefacts were present within the vicinity of the ice-layer due to the scattering of the laser light, especially near the inlet of the channel where the ice-layer is curved instead of flat. LIF measurements taken within a short time span prior to the onset of ice freezing showed approximately 2 °C of subcooling, consistent with previous findings. In addition, an anomalous behavior within the thermal boundary layer was observed, with a much smaller temperature gradient within the first few mm above the cold plate and a point of inflection in the temperature profile. The anomalous temperature behavior is possibly attributed to enhanced natural convection as a result of the subcooling at the cold plate surface.","Laminar internal flow; Laser Induced Fluorescence; Non-intrusive temperature measurements; Transient freezing","en","journal article","","","","","","","","","","RST/Radiation, Science and Technology","RST/Reactor Physics and Nuclear Materials","","",""
"uuid:478c5b9b-eb91-4d86-aa82-42d0c3af003b","http://resolver.tudelft.nl/uuid:478c5b9b-eb91-4d86-aa82-42d0c3af003b","The value of a mobile educative Application additional to Standard counselling on aspirin Adherence in Pregnancy: the ASAP study, a randomised controlled trial","bij de Weg, Jeske M. (Vrije Universiteit Amsterdam; Amsterdam Reproduction and Development Research Institute, Amsterdam); de Boer, Marjon A. (Vrije Universiteit Amsterdam; Amsterdam Reproduction and Development Research Institute, Amsterdam); Meijer, Cynthia (Vrije Universiteit Amsterdam; Amsterdam Reproduction and Development Research Institute, Amsterdam); Lugtenburg, Noëlle (Student TU Delft); Melles, M. (TU Delft Applied Ergonomics and Design); de Vries, Johanna I.P. (Vrije Universiteit Amsterdam; Amsterdam Reproduction and Development Research Institute, Amsterdam); de Groot, Christianne J.M. (Vrije Universiteit Amsterdam; Amsterdam Reproduction and Development Research Institute, Amsterdam)","","2024","Objective: To assess the added value of a novel, mobile educative application to standard counselling on aspirin adherence during pregnancy versus standard counselling alone. Methods: Participants were randomly assigned for additional use of a mobile educative application or standard counselling alone. Main outcome measures were adherence to aspirin measured by two validated questionnaires: Simplified Medication Adherence Questionnaire (SMAQ), Believes and Behaviour Questionnaire (BBQ), and patients reported tablet intake >90%. Results: A total of 174 women with an indication for aspirin during pregnancy were included. The questionnaires were filled in by 126 out of the 174 participants (72.4%). Similar results were found in the app group and the standard counselling groups for both validated questionnaires. Tablet intake >90% was seen in 88.7% and 87.5% (p = 0.834) of the app group and standard counselling group respectively. Subgroup analyses demonstrated a negative effect of BMI and a positive effect of educational level on adherence. Conclusions: Our study revealed no added effect of a novel, mobile educative application to standard counselling on aspirin adherence during pregnancy. Tablet intake was equally high in both groups probably explained by our high educated population. Innovation: Future studies should focus on tailored counselling on medication to pregnant women's needs including medication reminders, addressing concerns, adequate health literacy and side effects, offering rewards to further stimulate aspirin adherence in pregnancy with optimal outcome for mother and their neonate.","Adherence; Aspirin; Counselling; Education; Educative application; Pregnancy","en","journal article","","","","","","","","","","","Applied Ergonomics and Design","","",""
"uuid:69a3750d-8ca1-4e18-99cc-00ba97e66955","http://resolver.tudelft.nl/uuid:69a3750d-8ca1-4e18-99cc-00ba97e66955","A review on machine learning in flexible surgical and interventional robots: Where we are and where we are going","Wu, D. (TU Delft Medical Instruments & Bio-Inspired Technology; Katholieke Universiteit Leuven); Zhang, R. (TU Delft Human-Robot Interaction; Universiteit Leiden); Pore, Ameya (Universitat Politecnica de Catalunya; University of Verona); Ha, Xuan Thao (Katholieke Universiteit Leuven; Scuola Superiore Sant’Anna); Li, Z. (TU Delft Medical Instruments & Bio-Inspired Technology; Politecnico di Milano); Herrera, Fernando (Katholieke Universiteit Leuven; University of Strasbourg); Kowalczyk, Wojtek (Universiteit Leiden); De Momi, Elena (Politecnico di Milano); Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology); Kober, J. (TU Delft Learning & Autonomous Control)","","2024","Minimally Invasive Procedures (MIPs) emerged as an alternative to more invasive surgical approaches, offering patient benefits such as smaller incisions, less pain, and shorter hospital stay. In one class of MIPs, where natural body lumens or small incisions are used to access deeper anatomical locations, Flexible Surgical and Interventional Robots (FSIRs) such as catheters and endoscopes are widely used. Due to their flexible and compliant nature, FSIRs can be inserted via natural orifices or small incisions, then moved towards hard-to-reach targets to perform interventional tasks. However, existing FSIRs are confronted with challenges in sensing, control, and navigation. These issues stem from the robot's non-linear behavior and the intricate nature of the lumens, where accurately modeling the complex interactions and disturbances proves to be exceptionally difficult. The rapid advances in Machine Learning (ML) have facilitated the widespread adoption of ML techniques in FSIRs. This article provides an overview of these efforts by first introducing a classification of existing ML algorithms, including traditional ML methods and modern Deep Learning (DL) approaches, commonly used in FSIRs. Next, the use of ML algorithms is surveyed per sub-domain, namely for perception, modeling, control, and navigation. Trends, popularity, strengths, and/or limitations of different ML algorithms are analyzed. The different roles that ML plays among tasks are investigated and described. Finally, discussions are conducted on the limitations and the prospects of ML in MIPs.","Control; Flexible surgical and interventional robots; Machine learning; Modeling; Navigation; Sensing","en","review","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:c4c1a755-e776-45a3-9660-14050242eca8","http://resolver.tudelft.nl/uuid:c4c1a755-e776-45a3-9660-14050242eca8","Low disorder and high valley splitting in silicon","Degli Esposti, D. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Stehouwer, L.E.A. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Gül, Önder (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; TNO); Samkharadze, Nodar (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; TNO); Déprez, C.C. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Meyer, M. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Meijer, Ilja N. (Kavli institute of nanoscience Delft; Student TU Delft); Tryputen, L. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; TNO); Karwal, S. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; TNO); Vandersypen, L.M.K. (TU Delft QuTech Advanced Research Centre; TU Delft QN/Vandersypen Lab; Kavli institute of nanoscience Delft); Sammak, A. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; TNO); Veldhorst, M. (TU Delft QN/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2024","The electrical characterisation of classical and quantum devices is a critical step in the development cycle of heterogeneous material stacks for semiconductor spin qubits. In the case of silicon, properties such as disorder and energy separation of conduction band valleys are commonly investigated individually upon modifications in selected parameters of the material stack. However, this reductionist approach fails to consider the interdependence between different structural and electronic properties at the danger of optimising one metric at the expense of the others. Here, we achieve a significant improvement in both disorder and valley splitting by taking a co-design approach to the material stack. We demonstrate isotopically purified, strained quantum wells with high mobility of 3.14(8) × 105 cm2 V−1 s−1 and low percolation density of 6.9(1) × 1010 cm−2. These low disorder quantum wells support quantum dots with low charge noise of 0.9(3) μeV Hz−1/2 and large mean valley splitting energy of 0.24(7) meV, measured in qubit devices. By striking the delicate balance between disorder, charge noise, and valley splitting, these findings provide a benchmark for silicon as a host semiconductor for quantum dot qubits. We foresee the application of these heterostructures in larger, high-performance quantum processors.","","en","journal article","","","","","","","","","","","QCD/Scappucci Lab","","",""
"uuid:d5f9bd8c-3c51-462e-8cf0-472864e1a798","http://resolver.tudelft.nl/uuid:d5f9bd8c-3c51-462e-8cf0-472864e1a798","A highly stable, pressure-driven, flow control system based on Coriolis mass flow sensors for organs-on-chips","de Haan, Pim (Rijksuniversiteit Groningen; TI-COAST); Mulder, Jean Paul S.H. (Rijksuniversiteit Groningen); Lötters, J.C. (TU Delft Precision and Microsystems Engineering; Bronkhorst High-Tech BV; University of Twente); Verpoorte, Elisabeth (Rijksuniversiteit Groningen)","","2024","Stable delivery of liquids to microfluidic systems is essential for their reproducible functioning, especially when supplying flows to organs-on-chips – delicate living models that recreate human physiology on the microscale and thus can be used to reduce the need for animal testing. Most flow control systems are unable to sustain a robust and stable flow in longer experiments (>1 week), particularly those based on the ubiquitous syringe pump. Though easy to use, syringe pumps have no mechanism for actually measuring flow, let alone flow regulation with sensor feedback. We have developed a liquid delivery system based on the generation of flow by applying a constant air pressure to liquids in sealed containers. A flow of liquid is monitored by accurate measurement of mass flows (mg/min) using downstream Coriolis-based mass flow sensors. Measured mass flows provide fast feedback to integrated valves, with valves opening or closing slightly to increase or decrease solution flows to the organs-on-chips as required. This mass flow sensing principle is not affected by changes in the density, temperature, and viscosity of the liquids being displaced. This is in contrast to systems that use volumetric flow sensors, which require recalibration when these parameters change. The rationale behind using this principle for organs-on-chips, is that the stability provided by this flow control system allows for more control over growth of these mini-organs. We demonstrate the functionality of this system with three examples: 1) Fast stabilization (within seconds) under changing physical conditions; 2) Short-term stability (minutes to hours) of delivered flows in a microreactor with interconnected inlets; and 3) Long-term stability (>1 week) of cell medium flows to a living organ-on-a-chip. Two categories of organs-on-chips (OOCs) can be distinguished: 1) solid OOC are designed for three-dimensional cell or tissue constructs that interact with each other and their surroundings, and 2) barrier-type OOC contain a selective cellular barrier between two compartments as do many barriers in the body. The latter of these two types is the most challenging to culture and maintain as they are very sensitive to variations in flow and pressure surges. The flow control system presented in this work provides a great improvement compared to the use of syringe pumps and volumetric flow sensors in OOC studies. The novelty of this work lies in the long-term stability use of this system for organs-on-chips, maintaining stability for short to very long periods of time without compromising the barrier function of the organ-on-chip by pressure surges, bacterial contamination, or other undesired effects from the flow delivery system.","Coriolis flow sensor; Flow control system; Flow stability; Organ-on-a-chip","en","journal article","","","","","","","","","","Precision and Microsystems Engineering","","","",""
"uuid:87f5a71c-272b-4c71-842d-984cb6980710","http://resolver.tudelft.nl/uuid:87f5a71c-272b-4c71-842d-984cb6980710","Cross-coupled iterative learning control: A computationally efficient approach applied to an industrial flatbed printer","Aarnoudse, Leontine (Eindhoven University of Technology); Kon, Johan (Eindhoven University of Technology); Classens, Koen (Eindhoven University of Technology); van Meer, Max (Eindhoven University of Technology); Poot, Maurice (Eindhoven University of Technology); Tacx, Paul (Eindhoven University of Technology); Strijbosch, Nard (Eindhoven University of Technology); Oomen, T.A.E. (TU Delft Team Jan-Willem van Wingerden; Eindhoven University of Technology)","","2024","Cross-coupled iterative learning control (ILC) can improve the contour tracking performance of manufacturing systems significantly. This paper aims to develop a framework for norm-optimal cross-coupled ILC that enables intuitive tuning of time- and iteration-varying weights of the exact contour error and its tangential counterpart. This leads to an iteration-varying ILC algorithm for which convergence conditions are developed. In addition, a resource-efficient implementation is developed that reduces the computational load significantly and enables the use of long reference signals. The approach is experimentally validated on an industrial flatbed printer.","Contour tracking; Feedforward control; Iterative learning control","en","journal article","","","","","","","","","","","Team Jan-Willem van Wingerden","","",""
"uuid:791b8078-187c-4f98-bfac-6367f832f243","http://resolver.tudelft.nl/uuid:791b8078-187c-4f98-bfac-6367f832f243","Adaptive approximate computing in edge AI and IoT applications: A review","Damsgaard, Hans Jakob (Tampere University); Grenier, Antoine (Tampere University); Katare, D. (TU Delft Information and Communication Technology); Taufique, Zain (University of Turku); Shakibhamedan, Salar (Technische Universität Wien); Troccoli, Tiago (Wirepas Ltd, Tampere); Chatzitsompanis, Georgios (Queen's University Belfast); Kanduri, Anil (University of Turku); Ding, Aaron Yi (TU Delft Information and Communication Technology)","","2024","Recent advancements in hardware and software systems have been driven by the deployment of emerging smart health and mobility applications. These developments have modernized the traditional approaches by replacing conventional computing systems with cyber–physical and intelligent systems combining the Internet of Things (IoT) with Edge Artificial Intelligence. Despite the many advantages and opportunities of these systems within various application domains, the scarcity of energy, extensive computing needs, and limited communication must be considered when orchestrating their deployment. Inducing savings in these directions is central to the Approximate Computing (AxC) paradigm, in which the accuracy of some operations is traded off with energy, latency, and/or communication reductions. Unfortunately, the dynamics of the environments in which AxC-equipped IoT systems operate have been paid little attention. We bridge this gap by surveying adaptive AxC techniques applied to three emerging application domains, namely autonomous driving, smart sensing and wearables, and positioning, paying special attention to hardware acceleration. We discuss the challenges of such applications, how adaptive AxC can aid their deployment, and which savings it can bring based on traits of the data and devices involved. Insights arising thereof may serve as inspiration to researchers, engineers, and students active within the considered domains.","Approximate computing; Autonomous driving; Edge computing; Positioning; Smart sensing","en","review","","","","","","","","","","","Information and Communication Technology","","",""
"uuid:3b418202-a2f4-4627-bc9c-141243e3968b","http://resolver.tudelft.nl/uuid:3b418202-a2f4-4627-bc9c-141243e3968b","Skin marker-based versus bone morphology-based coordinate systems of the hindfoot and forefoot","Hulshof, Chantal M. (Universiteit van Amsterdam; Vrije Universiteit Amsterdam; Amsterdam Movement Sciences); Schallig, Wouter (Universiteit van Amsterdam; Vrije Universiteit Amsterdam; Amsterdam Movement Sciences); van den Noort, Josien C. (Universiteit van Amsterdam; Amsterdam Movement Sciences); Streekstra, Geert J. (Universiteit van Amsterdam); Kleipool, Roeland P. (Universiteit van Amsterdam); GG Dobbe, Johannes (Universiteit van Amsterdam); Maas, Mario (Universiteit van Amsterdam; Amsterdam Movement Sciences); Harlaar, J. (TU Delft Biomechatronics & Human-Machine Control; Vrije Universiteit Amsterdam; Erasmus MC); van der Krogt, Marjolein M. (Universiteit van Amsterdam; Vrije Universiteit Amsterdam; Amsterdam Movement Sciences)","","2024","Segment coordinate systems (CSs) of marker-based multi-segment foot models are used to measure foot kinematics, however their relationship to the underlying bony anatomy is barely studied. The aim of this study was to compare marker-based CSs (MCSs) with bone morphology-based CSs (BCSs) for the hindfoot and forefoot. Markers were placed on the right foot of fifteen healthy adults according to the Oxford, Rizzoli and Amsterdam Foot Model (OFM, RFM and AFM, respectively). A CT scan was made while the foot was loaded in a simulated weight-bearing device. BCSs were based on axes of inertia. The orientation difference between BCSs and MCSs was quantified in helical and 3D Euler angles. To determine whether the marker models were able to capture inter-subject variability in bone poses, linear regressions were performed. Compared to the hindfoot BCS, all MCSs were more toward plantar flexion and internal rotation, and RFM was also oriented toward more inversion. Compared to the forefoot BCS, OFM and RFM were oriented more toward dorsal and plantar flexion, respectively, and internal rotation, while AFM was not statistically different in the sagittal and transverse plane. In the frontal plane, OFM was more toward eversion and RFM and AFM more toward inversion compared to BCS. Inter-subject bone pose variability was captured with RFM and AFM in most planes of the hindfoot and forefoot, while this variability was not captured by OFM. When interpreting multi-segment foot model data it is important to realize that MCSs and BCSs do not always align.","Bone poses; Computed tomography; Gait analysis; Kinematics; Multi-segment foot model","en","journal article","","","","","","","","","","","Biomechatronics & Human-Machine Control","","",""
"uuid:d1b254fe-aa53-410a-87f8-90c5a8f6a44a","http://resolver.tudelft.nl/uuid:d1b254fe-aa53-410a-87f8-90c5a8f6a44a","ETVO: Effectively Measuring Tactile Internet With Experimental Validation","Kroep, H.J.C. (TU Delft Networked Systems; TU Delft Embedded Systems); Gokhale, V. (TU Delft Networked Systems); Verburg, Joseph (Student TU Delft); Venkatesha Prasad, Ranga Rao (TU Delft Networked Systems)","","2024","The next frontier in communications is teleoperation - manipulation and control of remote environments with haptic feedback. Compared to conventional networked applications, teleoperation poses widely different requirements, ultra-low latency (ULL) is primary. Realizing ULL communication demands significant redesign of conventional networking techniques, and the network infrastructure envisioned for achieving this is termed as Tactile Internet (TI). The design of meaningful performance metrics is crucial for seamless TI communication. However, existing performance metrics fall severely short of comprehensively characterizing TI performance due to their inability to capture how well sensed signals are reproduced. We take Dynamic Time Warping(DTW) as the basis of our work and identify necessary changes for characterizing TI performance. Through substantial refinements to DTW, we design Effective Time- and Value-Offset (ETVO) - a new method for measuring the fine-grained performance of TI systems. Through an in-depth objective analysis, we demonstrate the improvements of ETVO over DTW. Through subjective experiments, we demonstrate that existing QoS and QoE methods fall short of estimating the TI session performance accurately. Using subjective experiments, we demonstrate the behavior of the proposed metrics, their ability to match theoretically derived performance, and finally, their ability to reflect user satisfaction in a practical setting.","Delays; Measurement; QoS; Quality of experience; Quality of service; Reliability; Surgery; tactile internet; Tactile Internet; URLLC; user experience","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Networked Systems","","",""
"uuid:5501c983-6dd4-46a7-81aa-be9839655272","http://resolver.tudelft.nl/uuid:5501c983-6dd4-46a7-81aa-be9839655272","High-Confidence Data-Driven Ambiguity Sets for Time-Varying Linear Systems","Boskos, D. (TU Delft Team Dimitris Boskos); Cortes, Jorge (University of California); Martinez, Sonia (University of California)","","2024","This paper builds Wasserstein ambiguity sets for the unknown probability distribution of dynamic random variables leveraging noisy partial-state observations. The constructed ambiguity sets contain the true distribution of the data with quantifiable probability and can be exploited to formulate robust stochastic optimization problems with out-of-sample guarantees. We assume the random variable evolves in discrete time under uncertain initial conditions and dynamics, and that noisy partial measurements are available. All random elements have unknown probability distributions and we make inferences about the distribution of the state vector using several output samples from multiple realizations of the process. To this end, we leverage an observer to estimate the state of each independent realization and exploit the outcome to construct the ambiguity sets. We illustrate our results in an economic dispatch problem involving distributed energy resources over which the scheduler has no direct control.","Aerodynamics; Distributional uncertainty; estimation; linear system observers; Noise measurement; Optimization; Power system dynamics; Probability distribution; Random variables; stochastic systems; Uncertainty","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-08","","","Team Dimitris Boskos","","",""
"uuid:3e973f93-e4c6-4067-8e43-ca7931028de1","http://resolver.tudelft.nl/uuid:3e973f93-e4c6-4067-8e43-ca7931028de1","Distributed Adaptive Synchronization in Euler Lagrange Networks with Uncertain Interconnections","Tao, T. (TU Delft Team Bart De Schutter); Roy, Spandan (International Institute of Information Technology); De Schutter, B.H.K. (TU Delft Delft Center for Systems and Control); Baldi, S. (TU Delft Team Bart De Schutter; Southeast University)","","2024","In this work we propose a new practical synchronization protocol for multiple Euler Lagrange (EL) systems without structural linear-in-the-parameters (LIP) knowledge of the uncertainty and where the agents can be interconnected before control design by unknown state-dependent interconnection terms. This setting is meant to overcome two standard a priori assumptions in the literature concerning uncertainty with LIP structure and absence of interaction among agents before designing the synchronization protocol. To overcome these assumptions, we propose an adaptive distributed control mechanism having the purpose of estimating the coefficients of the resulting state-dependent uncertainty structure.","Adaptive synchronization; Adaptive systems; bounded interconnections; Control design; Euler Lagrange dynamics; Friction; heterogeneous networks; Lips; Standards; Synchronization; Uncertainty","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-10","","Delft Center for Systems and Control","Team Bart De Schutter","","",""
"uuid:9e4b4c23-d1ed-4355-85a6-7a56aa2b839a","http://resolver.tudelft.nl/uuid:9e4b4c23-d1ed-4355-85a6-7a56aa2b839a","Hybrid Tunable Magnet Actuator: Design of a Linearized Force-Flux Tunable Magnet Actuator","Hoekwater, William B. (Student TU Delft); Ronaes, E.P. (TU Delft Mechatronic Systems Design); Hassan HosseinNia, S. (TU Delft Mechatronic Systems Design)","","2024","Recent studies have shown that tunable magnets (soft permanent magnets) can significantly reduce Joule heating in electromagnetic actuators. To achieve high motion accuracy and repeatability, this article proposes a novel actuator design with a linearized force-flux relation. In prior designs of variable reluctance tunable magnet actuators, the force and flux are related quadratically via a C-shaped actuator. Hybrid tunable magnet actuators based on biased fluxes are developed using lumped parameter models. Using finite element analysis, it is shown that the force-flux relation is symmetric linear around the mid position depending on the magnetic flux direction in the magnet. Within a position range of ±500 μm and a force range of ±20 N, the linear fit produces a negligible error of 0.08 N. Finally, this linear relationship is validated with a 0.03-N error in an experimental setup.","Actuators; Force; Magnetic circuits; Magnetic flux; Magnetic hysteresis; Magnetic separation; Magnetomechanical effects; Saturation magnetization; tunable magnets; variable reluctance actuator","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-19","","","Mechatronic Systems Design","","",""
"uuid:eb661d08-fc10-4b5c-824d-72d68e00da85","http://resolver.tudelft.nl/uuid:eb661d08-fc10-4b5c-824d-72d68e00da85","Successive approximations and interval halving for fractional BVPs with integral boundary conditions","Marynets, K. (TU Delft Mathematical Physics); Pantova, D.H. (TU Delft Mathematical Physics)","","2024","We study a system of non-linear fractional differential equations, subject to integral boundary conditions. We use a parametrization technique and a dichotomy-type approach to reduce the original problem to two “model-type” fractional boundary value problems with linear two-point boundary conditions. A numerical-analytic technique is applied to analytically construct approximate solutions to the “model-type” problems. The behaviour of these approximate solutions is governed by a set of parameters, whose values are obtained by numerically solving a system of algebraic equations. The obtained results are confirmed by an example of the fractional order problem that in the case of the second order differential equation models the Antarctic Circumpolar Current.","Approximation of solutions; Dichotomy-type approach; Fractional differential equations; Fractional geophysical model; Integral boundary conditions; Parametrization","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:d909f711-a050-44d1-9b24-de97a94eaa1b","http://resolver.tudelft.nl/uuid:d909f711-a050-44d1-9b24-de97a94eaa1b","Governing capabilities, not places – how to understand social sustainability implementation in urban development","Janssen, C. (TU Delft Practice Chair Urban Area Development); Daamen, T.A. (TU Delft Urban Development Management); Verheul, W.J. (TU Delft Urban Development Management)","","2024","Social sustainability’s implementation in urban development is a complex endeavour that demands alternative forms of governance. This article draws on the capabilities approach as an evaluative framework to better understand this implementation process. Through an in-depth case comparison of two Dutch urban development projects, the study analyses how collaborative governance situations (i.e. actors, activities and phases) relate to the expansions of resident capabilities in the urban areas. The findings present three principles for a ‘capability-centred governance’ of social sustainability in urban development: (1) integrate human logic into urban governance situations (2) balance strong goal commitment with experimentalist approaches and (3) institutionalise social sustainability implementation. The article concludes that social sustainability’s implementation requires a conceptualisation in which improvements in people’s lives are not seen as the self-evident consequences of a set of place-based policy interventions, but instead as a guiding principle that should continuously be reflected upon and learned from during the different phases of urban development processes.","capabilities approach; collaborative governance; policy implementation; social sustainability; urban development projects","en","journal article","","","","","","","","","","","Practice Chair Urban Area Development","","",""
"uuid:268a3b5b-fc9b-418f-948d-16530e661d33","http://resolver.tudelft.nl/uuid:268a3b5b-fc9b-418f-948d-16530e661d33","A Pitch-Matched High-Frame-Rate Ultrasound Imaging ASIC for Catheter-Based 3-D Probes","Hopf, Y.M. (TU Delft Electronic Instrumentation); Simoes dos Santos, D. (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Verweij group); Ossenkoppele, Boudewine W. (Student TU Delft); Noothout, E.C. (TU Delft ImPhys/Verweij group); Chang, Z.Y. (TU Delft Electronic Instrumentation); Chen, Chao (Student TU Delft); Vos, H.J. (TU Delft ImPhys/Verweij group; Erasmus MC); Verweij, M.D. (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Verweij group; Erasmus MC); de Jong, N. (TU Delft ImPhys/De Jong group; Erasmus MC); Pertijs, M.A.P. (TU Delft Electronic Instrumentation)","","2024","This article presents an application-specific integrated circuit (ASIC) for catheter-based 3-D ultrasound imaging probes. The pitch-matched design implements a comprehensive architecture with high-voltage (HV) transmitters, analog front ends, hybrid beamforming analog-To-digital converters (ADCs), and data transmission to the imaging system. To reduce the number of cables in the catheter while maintaining a small footprint per element, transmission (TX) beamforming is realized on the chip with a combination of a shift register (SR) and a row/column (R/C) approach. To explore an additional cable-count reduction in the receiver part of the design, a channel with a combination of time-division multiplexing (TDM), subarray beamforming, and multi-level pulse amplitude modulation (PAM) data transmission is also included. This achieves an 18-fold cable-count reduction and minimizes the power consumption in the catheter by a load modulation (LM) cable driver. It is further explored how common-mode interference can limit beamforming gain and a strategy to reduce its impact with local regulators is discussed. The chip was fabricated in TSMC 0.18-m HV BCD technology and a 2-D PZT transducer matrix of 16 × 18 elements with a pitch of 160 m and a center frequency of 6 MHz was manufactured on the chip. The system can generate all required TX patterns at up to 30 V, provides quick settling after the TX phase, and has an reception (RX) power consumption of only 1.12 mW/element. The functionality and operation of up to 1000 volumes/s have been demonstrated in electrical and acoustic imaging experiments.","3-D ultrasound; analog front end (AFE); common-mode interference suppression; high frame rate; intracardiac echocardiography (ICE); load-modulation datalink; transmit beamformer; transmit/receive (T/R) switching; ultrasound application-specific integrated circuit (ASIC)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-30","","","Electronic Instrumentation","","",""
"uuid:08269340-4715-4af0-b3c9-4aaed36771ab","http://resolver.tudelft.nl/uuid:08269340-4715-4af0-b3c9-4aaed36771ab","On a multiple time-scales perturbation analysis of a Stefan problem with a time-dependent Dirichlet boundary condition","Ihsan, A.F. (TU Delft Mathematical Physics; Institute of Technology Bandung); van Horssen, W.T. (TU Delft Mathematical Physics); Tuwankotta, J.M. (TU Delft Mathematical Physics; Institute of Technology Bandung)","","2024","In this paper, a classical Stefan problem with a prescribed and small time-dependent temperature at the boundary is studied. By using a multiple time-scales perturbation method, it is shown analytically how the moving boundary profile is influenced by the prescribed temperature at the boundary and the initial conditions. Only a few exact solutions are available for this type of problems and it turns out that the constructed approximations agree very well with these exact solutions. In particular, approximations of solutions for this type of problems, with periodic and decaying temperatures at the boundary, are constructed. Furthermore, these approximations are valid on a long time scale, and seems to be not available in the literature.","Multiple time-scales; Stefan problem; Time-dependent boundary temperature","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-08","","","Mathematical Physics","","",""
"uuid:08752acf-f898-4c41-ae7b-966f3a8fa17d","http://resolver.tudelft.nl/uuid:08752acf-f898-4c41-ae7b-966f3a8fa17d","The conflicting geographies of social frontiers: Exploring the asymmetric impacts of social frontiers on household mobility in Rotterdam","Olner, Dan (University of Sheffield); Pryce, Gwilym (University of Sheffield); van Ham, M. (TU Delft Urbanism); Janssen, H.J. (TU Delft Urban Studies)","","2024","Social frontiers arise when there are sharp differences in the demographic composition of adjacent communities. This paper provides the first quantitative study of their impact on household mobility. We hypothesise that conflicting forces of white flight and territorial allegiance lead to asymmetrical effects, impacting residents on one side of the frontier more than the other due to differences in the range of housing options available to different groups, and different symbolic interpretations of the frontier. Using Dutch registry data for the city of Rotterdam we identify ethnic social frontier locations using a Bayesian spatial model (Dean et al., 2019), exploiting the data’s one hundred metre resolution to estimate frontiers at a very small spatial scale. Regression analysis of moving decisions finds that the ethnic asymmetry of the frontier matters more than ethnicity of individual households. On the ethnic minority side of the frontier, households of all ethnicities in the 28–37 age range have reduced probability of moving compared to non-frontier parts of the city. The opposite is true on the Dutch native side of the frontier. We supplement this analysis with flow models which again find strong frontier effects. Our findings illustrate how the study of social frontiers can shed light on local population dynamics and neighbourhood change.","geographical mobility; immigration; Netherlands; segregation; Social frontiers","en","journal article","","","","","","","","","","Urbanism","Urban Studies","","",""
"uuid:b703690f-f56a-4fa7-8c96-40f983689d35","http://resolver.tudelft.nl/uuid:b703690f-f56a-4fa7-8c96-40f983689d35","Fuel consumption prediction for pre-departure flights using attention-based multi-modal fusion","Lin, Yi (Sichuan University); Guo, Dongyue (Sichuan University); Wu, Yuankai (McGill University); Li, L. (TU Delft Air Transport & Operations; City University of Hong Kong); Wu, Edmond Q. (Key Laboratory of System Control and Information Processing, Ministry of Education); Ge, Wenyi (Chengdu University of Information Technology)","","2024","Improper fuel loading decision results in carrying excessive dead weight during flight operation, which will burden the airline operation cost and cause extra waste emission. Existing works mainly focused on the post-event fuel consumption based on flight trajectory. In this work, a novel deep learning model, called FCPNet, is proposed to achieve the fuel consumption prediction (FCP) before the flight departure. Considering the influential factors for aircraft performance, the multi-modal information sources, including the planned route, weather information, and operation details, are selected as the model input to predict fuel consumption. Correspondingly, three modules are innovatively proposed to learn embedding features from multi-modal inputs. Based on the planned route, the graph convolutional network is proposed to mine the spatial correlations in the non-Eulerian route network. Considering the grid attributes of the weather information, the ConvLSTM is applied to learn abstract representations from both the temporal and spatial dimensions, in which the three-dimensional convolution neural networks are also designed to fine-tune intermediate feature maps. The fully connected layer is also proposed to learn informative features from operation details. Finally, an attention-based fusion network is presented to generate the final embedding by considering the unique contributions of the multi-modality sources, which are further applied to predict flight fuel consumption. A binary encoding representation is proposed to formulate the FCP task as a multi-binary classification problem. The proposed model is validated on a real-world dataset, and the results demonstrate that it outperforms other baselines, i.e., achieving a 6.50% mean absolute percentage error, which can practically support the airline operation and global emission control before flight departure.","Attention mechanism; ConvLSTM; Graph convolutional network; Multi-modal fusion; Pre-departure fuel consumption prediction","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-26","","","Air Transport & Operations","","",""
"uuid:a7f84fae-2283-488d-8d22-a9ea4900014d","http://resolver.tudelft.nl/uuid:a7f84fae-2283-488d-8d22-a9ea4900014d","Real-time reconstruction of unsteady rotating forces acting by rotor blades in moving medium","Xu, Ying (Hefei University of Technology); Casalino, D. (TU Delft Wind Energy); Zhang, Xiao Zheng (Hefei University of Technology); Zhang, Yong Bin (Hefei University of Technology); Bi, Chuan Xing (Hefei University of Technology)","","2024","A time-domain inverse aeroacoustic method based on the convective Ffowcs Williams–Hawkings equation is presented. The method allows to determine, in real-time, the unsteady forces exerted on rotating blades in the presence of a moving medium. The inversion procedure is based on a space-time regularization with a mixed l1,2-norm, which guarantees accuracy and smoothness of the solution. The method is initially verified through synthetic acoustic signals emitted by rotating sources in a constant flow, up to a convective Mach number of about 0.88. Then the method is validated through signals generated by a propeller immersed in a wind-tunnel jet flow, up to a Mach number of 0.06. Due to the reduced convective Mach number, the leading aeroacoustic effect is derived from a variation of the blade loading. It is argued that the onset of flow separation at high values of the rotor advance ratio is responsible for the onset of force fluctuations that the inverse method is able to retrieve both qualitatively and quantitatively.","Inverse aeroacoustic method; Moving medium; Real-time reconstruction; Rotor noise; Unsteady rotating forces","en","journal article","","","","","","","","2024-01-01","","","Wind Energy","","",""
"uuid:6c851b17-4bde-48d5-84f4-b43220d9c3dc","http://resolver.tudelft.nl/uuid:6c851b17-4bde-48d5-84f4-b43220d9c3dc","Less stick more carrot? Increasing the uptake of deposit contract financial incentives for physical activity: A randomized controlled trial","de Buisonjé, David R. (Universiteit Leiden); Reijnders, T. (TU Delft Design Aesthetics; Universiteit Leiden); Cohen Rodrigues, Talia R. (Universiteit Leiden); Santhanam, Prabhakaran (ETH Zürich); Kowatsch, Tobias (ETH Zürich; University of Zürich; University of St. Gallen); Breeman, Linda D. (Universiteit Leiden); Janssen, Veronica R. (Universiteit Leiden; Leiden University Medical Center); Kraaijenhagen, Roderik A. (Hearts4people Foundation); Kemps, Hareld M.C. (Maxima Medical Center, Veldhoven; Eindhoven University of Technology); Evers, A.W.M. (TU Delft Applied Ergonomics and Design; Universiteit Leiden; Erasmus Universiteit Rotterdam)","","2024","Background: Financial incentives are a promising tool to help people increase their physical activity, but they are expensive to provide. Deposit contracts are a type of financial incentive in which participants pledge their own money. However, low uptake is a crucial obstacle to the large-scale implementation of deposit contracts. Therefore, we investigated whether (1) matching the deposit 1:1 (doubling what is deposited) and (2) allowing for customizable deposit amounts increased the uptake and short term effectiveness of a deposit contract for physical activity. Methods: In this randomized controlled trial, 137 healthy students (age M = 21.6 years) downloaded a smartphone app that provided them with a tailored step goal and then randomized them to one of four experimental conditions. The deposit contract required either a €10 fixed deposit or a customizable deposit with any amount between €1 and €20 upfront. Furthermore, the deposit was either not matched or 1:1 matched (doubled) with a reward provided by the experiment. During 20 intervention days, daily feedback on goal progress and incentive earnings was provided by the app. We investigated effects on the uptake (measured as agreeing to participate and paying the deposit) and effectiveness of behavioral adoption (measured as participant days goal achieved). Findings: Overall, the uptake of deposit contracts was 83.2%, and participants (n = 113) achieved 14.9 out of 20 daily step goals. A binary logistic regression showed that uptake odds were 4.08 times higher when a deposit was matched (p = .010) compared to when it was not matched. Furthermore, uptake odds were 3.53 times higher when a deposit was customizable (p = .022) compared to when it was fixed. Two-way ANCOVA showed that matching (p = .752) and customization (p = .143) did not impact intervention effectiveness. However, we did find a marginally significant interaction effect of deposit matching X deposit customization (p = .063, ηp2 = 0.032). Customization decreased effectiveness when deposits were not matched (p = .033, ηp2 = 0.089), but had no effect when deposits were matched (p = .776, ηp2 = 0.001). Conclusions: We provide the first experimental evidence that both matching and customization increase the uptake of a deposit contract for physical activity. We recommend considering both matching and customization to overcome lack of uptake, with a preference for customization since matching a deposit imposes significant additional costs. However, since we found indications that customizable deposits might reduce effectiveness (when the deposits are not matched), we urge for more research on the effectiveness of customizable deposit contracts. Finally, future research should investigate which participant characteristics are predictive of deposit contract uptake and effectiveness. Pre-registration: OSF Registries, https://osf.io/cgq48.","Behavior change; Deposit contracts; eHealth; Financial incentives; Physical activity; Rewards","en","journal article","","","","","","","","","","","Design Aesthetics","","",""
"uuid:6b600371-f799-449e-8f95-517ebaef978b","http://resolver.tudelft.nl/uuid:6b600371-f799-449e-8f95-517ebaef978b","Optimally reconfiguring list and correspondence colourings","Cambie, Stijn (Radboud Universiteit Nijmegen; University of Warwick; Katholieke Universiteit Leuven); Cames van Batenburg, W.P.S. (TU Delft Discrete Mathematics and Optimization); Cranston, Daniel W. (Virginia Commonwealth University)","","2024","The reconfiguration graph Ck(G) for the k-colourings of a graph G has a vertex for each proper k-colouring of G, and two vertices of Ck(G) are adjacent precisely when those k-colourings differ on a single vertex of G. Much work has focused on bounding the maximum value of diamCk(G) over all n-vertex graphs G. We consider the analogous problems for list colourings and for correspondence colourings. We conjecture that if L is a list-assignment for a graph G with |L(v)|≥d(v)+2 for all v∈V(G), then diamCL(G)≤n(G)+μ(G). We also conjecture that if (L,H) is a correspondence cover for a graph G with |L(v)|≥d(v)+2 for all v∈V(G), then diamC(L,H)(G)≤n(G)+τ(G). (Here μ(G) and τ(G) denote the matching number and vertex cover number of G.) For every graph G, we give constructions showing that both conjectures are best possible, which also hints towards an exact form of Cereceda's Conjecture for regular graphs. Our first main result proves the upper bounds (for the list and correspondence versions, respectively) diamCL(G)≤n(G)+2μ(G) and diamC(L,H)(G)≤n(G)+2τ(G). Our second main result proves that both conjectured bounds hold, whenever all v satisfy |L(v)|≥2d(v)+1. We conclude by proving one or both conjectures for various classes of graphs such as complete bipartite graphs, subcubic graphs, cactuses, and graphs with bounded maximum average degree. The full paper can also be found at arxiv.org/abs/2204.07928.","","en","journal article","","","","","","","","","","","Discrete Mathematics and Optimization","","",""
"uuid:89ffbd88-1fd7-4c23-b3c3-25febdd69702","http://resolver.tudelft.nl/uuid:89ffbd88-1fd7-4c23-b3c3-25febdd69702","In-Situ early anomaly detection and remaining useful lifetime prediction for high-power white LEDs with distance and entropy-based long short-term memory recurrent neural networks","Wen, Minzhen (Fudan University); Ibrahim, Mesfin Seid (Wollo University); Meda, Abdulmelik Husen (The Hong Kong Polytechnic University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan Zhangjiang Institute)","","2024","High-power white light-emitting diodes (LEDs) have demonstrated superior efficiency and reliability compared to traditional white light sources. However, ensuring maximum performance for a prolonged lifetime use presents a significant challenge for manufacturers and end users, especially in safety–critical applications. Thus, identifying functional anomalies and predicting the remaining useful lifetime (RUL) is of enormous importance in the operational longevity of the device. To address such challenges, this study proposes a combination of distance-based Mahalanobis distance (MD), entropy generation rate (EGR), and deep learning models for improved anomaly detection and RUL prediction accuracy. Unlike conventional health indicators based on luminous flux data that are challenging to monitor relevant optical performance, the MD and EGR methods are employed to extract in-situ monitored thermal and electrical data as new health indicators. Long short-term memory recurrent neural networks (LSTM-RNN) and convolutional neural networks (CNN) are established to detect anomalies and predict the RUL. The accelerated degradation tests of 3 W high-power white LED have been conducted, and the online and offline collected experimental data are deployed for model development and performance evaluation. The performance of the proposed methods is compared against the Illuminating Engineering Society of North America (IESNA) TM-21 method. The results indicate that LSTM-RNN, when combined with either MD or EGR, can detect anomalies with significantly fewer data (70 %) than is typically required. Furthermore, a significant improvement in prediction accuracy in RUL prediction based on MD and EGR-constructed time series health indicators and employed with the LSTM-RNN model demonstrates the effectiveness of the proposed methods.","Anomaly detection; Deep Learning Algorithms; Entropy generation rate (EGR); Light-emitting diodes (LEDs); Mahalanobis distance (MD); Remaining Useful Lifetime (RUL) Prediction","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-06","","","Electronic Components, Technology and Materials","","",""
"uuid:cb6444be-f094-46bd-9b51-2df2ab00dba8","http://resolver.tudelft.nl/uuid:cb6444be-f094-46bd-9b51-2df2ab00dba8","Transforming Engineering Education in Learning Ecosystems for Resilient Engineers","Klaassen, R.G. (TU Delft Policy & Implementation); Hellendoorn, J. (TU Delft Cognitive Robotics); Bossen, R.H. (TU Delft Education and Student Affairs)","","2024","TU Delft education system is transformed on three levels: 1) new courses and projects in existing B.Sc. and M.Sc. programs for multidisciplinary and reflective learning; 2) new M.Sc. programs focusing on multi and interdisciplinarity, personal development, and professional skills; and 3) central Interdisciplinary Projects for Master Students from different programs. With these steps, the university offers students a learning ecosystem where identity-building can occur, fosters interdisciplinary teamwork, and strong interaction with the professional world and government is necessary to finish projects. In this article, the ecosystem will be explained, and results will be shared of surveys among students who experienced learning in the learning ecosystem. The surveys show that students under stand their future role in the community as engineers, feel that they have acquired new skills, feel better about framing complex problems, and are more competent to work in the industry.","Curriculum Renewal; Future Engineer; ecosystem; stakeholders; knolwedge engineering; education; ethics; teamwork; survey","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-18","","Cognitive Robotics","Policy & Implementation","","",""
"uuid:a081f421-da03-4c20-b567-6e271f9d0dd6","http://resolver.tudelft.nl/uuid:a081f421-da03-4c20-b567-6e271f9d0dd6","Perspectives on Assessing the Flexibility of Hospitals for Crisis Mode Operations: Lessons From the COVID-19 Pandemic in the Netherlands","van Heel, M.E. (TU Delft Design & Construction Management; Erasmus MC); Pretelt, Manuela (Royal HaskoningDHV); van Gelder, M.H. (TU Delft History, Form & Aesthetics; Wiegerinck, Arnhem); van Oel, C.J. (TU Delft Design & Construction Management)","","2024","Background: The COVID-19 pandemic placed healthcare design at the heart of the crisis. Hospitals faced challenges such as rapidly increasing their intensive care unit capacity, enabling physical distancing measures, quickly converting to telehealth and telework practices, and above all, keeping patients and staff safe. Improving flexibility in hospital facility design and adaptability of hospital operations to function in “crisis mode” can be seen as ways of future-proofing for pandemics. In a design brief, flexibility is typically mentioned as an important target. Meanwhile, robustness of technical infrastructure is called for, and standardization at unit level with single-occupancy inpatient accommodation may be considered a way to enhance flexibility and adaptability in dealing with a surge in infectious patients. Aim: To future-proof facility design with pandemic preparedness and resilience in mind, this study evaluated what kinds of interventions were taken in Dutch hospital facilities and what perspectives need to be considered when hospitals operate in crisis mode. Methods: We have collected data from facility and estate professionals from 30 Dutch hospitals. Using a practice-based approach, in-depth interviewing helped uncover and compare successful operational strategies and design elements that provided the flexibility needed in the early stages of the recent crisis. Results: As we looked at existing facilities and alterations made to allow hospitals to operate during the COVID-19 pandemic, we discovered that staff availability and adaptability were deemed crucial. Conclusion: We add the perspective of staff as an essential factor to be considered when future-proofing hospital facility desigr crisis mode operation.","flexibility; hospital design; pandemic resilience; robustness; staff adaptability","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:98c12a05-57dc-49ab-b0a2-e080f753a825","http://resolver.tudelft.nl/uuid:98c12a05-57dc-49ab-b0a2-e080f753a825","A Two-Stage Approach for a Mixed-Integer Economic Dispatch Game in Integrated Electrical and Gas Distribution Systems","Ananduta, W. (TU Delft Team Sergio Grammatico); Grammatico, S. (TU Delft Team Sergio Grammatico; TU Delft Team Bart De Schutter)","","2024","We formulate for the first time the economic dispatch problem among prosumers in an integrated electrical and gas distribution system (IEGDS) as a game equilibrium problem. Specifically, by approximating the nonlinear gas-flow equations either with a mixed-integer second-order cone (MISOC) or a piecewise affine (PWA) model and by assuming that electricity and gas prices depend linearly on the total consumption, we obtain a potential mixed-integer game. To compute an approximate generalized Nash equilibrium (GNE), we propose an iterative two-stage method that exploits a problem convexification and the gas-flow models. We quantify the quality of the computed solution and perform a numerical study to evaluate the performance of our method.","Aggregates; Computational modeling; Cost function; Costs; Economic dispatch; Games; generalized mixed-integer games; Generators; integrated electrical and gas systems (IEGSs); Mathematical models","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-29","","","Team Sergio Grammatico","","",""
"uuid:4f4f4781-1b32-4762-b27d-ce74016023f5","http://resolver.tudelft.nl/uuid:4f4f4781-1b32-4762-b27d-ce74016023f5","Changes in commuting mode and the relationship with psychological stress: A quasi-longitudinal analysis in urbanizing China","Tao, Y. (TU Delft Urban Studies; University of Cambridge); van Ham, M. (TU Delft Urbanism); Petrović, A. (TU Delft Urban Studies)","","2024","Emerging longitudinal research on the relationship between commuting mode and psychological wellbeing draws exclusively from cities in developed countries and the findings are not consistent. Our study contributes to the evidence base from urban China, where rapid urban growth has raised great concerns for urbanites’ commuting problems and psychological stress risks. Drawing upon the China Health and Nutrition Survey (2006–2015), we followed a quasi-longitudinal design to examine changes in commuting mode and the associations with long-term psychological stress. Crucially, the neighbourhood-level urbanicity scale was incorporated to analyse geographic variations in the commuting-stress relationship over time. The results show that maintaining car commuting and long-duration active commuting were associated with lower levels of psychological stress, while long-duration motorised commuting trips by car or public transport were predictive of higher stress levels. Moreover, high-urbanicity areas involved more active commuting trips and short motorised commuting trips, which were beneficial to long-term psychological wellbeing. In contrast, the commuting-related stress risks were noticeable in medium urbanicity areas, where the commuting duration by public transport was extremely high. Based on the socio-institutional context of urban growth in China, we recommend that urban governments should change the focus from expanding urban development land to improving urban amenities and urbanites’ wellbeing.","Commuting behavior; Developing countries; Health; Longitudinal designs; Subjective well-being; Urban growth","en","journal article","","","","","","","","","","Urbanism","Urban Studies","","",""
"uuid:c2c6c678-708a-49e9-b38d-9253bd5ced5a","http://resolver.tudelft.nl/uuid:c2c6c678-708a-49e9-b38d-9253bd5ced5a","Autonomic responses to pressure sensitivity of head, face and neck: Heart rate and skin conductance","Yang, W. (Harbin Ergineering University Yantai Research Institute; School of Design Hunan University); Chen, Tingshu (School of Design Hunan University); He, Renke (School of Design Hunan University); Goossens, R.H.M. (TU Delft Human-Centered Design; TU Delft Applied Ergonomics and Design); Huysmans, T. (TU Delft Applied Ergonomics and Design)","","2024","Subjective scales are frequently used in the design process of head-related products to assess pressure discomfort. Nevertheless, some users lack fundamental cognitive and motor abilities (e.g., paralyzed patients). Therefore, it is vital to find non-verbal measurements of pressure discomfort and pressure pain. This study gathered the autonomic response data (heart rate and skin conductance) of 30 landmarks in head, neck and face from 31 participants experiencing pressure discomfort and pressure pain. The results indicate that pressure stimulation can change heart rate (HR) and skin conductance (SC). SC can be more useful in assessing pressure discomfort than HR for specific landmarks, and SC also possesses a faster arousal rate than HR. Moreover, HR decreased in response to pressure stimulation, while SC decreased followed by an increase. In comparisons between genders, the subjective pressure discomfort threshold (PDT) and pressure pain threshold (PPT) of women were lower than those of men, but men's autonomic responses (HR and SC) were more intense. Furthermore, there was no linear correlation between subjective pressure thresholds (PDT and PPT) and autonomic response intensity. This study has significant implications for resolving ergonomic issues (pressure discomfort and pain) associated with head-related products.","Pressure discomfort; Head-related products; Physiological signals","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-26","","Human-Centered Design","Applied Ergonomics and Design","","",""
"uuid:e18134a3-5359-4e10-b49b-303085dcbad7","http://resolver.tudelft.nl/uuid:e18134a3-5359-4e10-b49b-303085dcbad7","Interference Mitigation for Automotive FMCW Radar Based on Contrastive Learning With Dilated Convolution","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Li, Runlong (Beijing University of Posts and Telecommunications); Zhang, Xinqi (Beijing University of Posts and Telecommunications); He, Yuan (Beijing University of Posts and Telecommunications)","","2024","As one of the crucial sensors for environment sensing, frequency modulated continuous wave (FMCW) radars are widely used in modern vehicles for driving assistance/autonomous driving. However, the limited frequency bandwidth and the increasing number of equipped radar sensors would inevitably cause mutual interference, degrading target detection and producing safety hazards. In this paper, a deep learning-based interference mitigation (IM) approach is proposed for FMCW radars by using the dilated convolution for network construction and a designated contrast learning strategy for training. The dilated convolution enlarges the receptive field of the neural network, and the designated contrastive learning strategy enforces to distinguish better between interferences and desired signals. The results of numerical simulation and experimental data processing show that the dilated convolution-based IM network, compared to the traditional convolution-based ones, can achieve a higher Signal-to-Interference-plus-Noise-Ratio (SINR) and target detection rate. Moreover, the designated contrastive learning strategy enables a better and more stable IM performance without increasing the complexity of the network, which can facilitate faster signal processing.","Automotive radar; interference mitigation; deep learning; dilated convolution; contrastive learning","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-31","","","Microwave Sensing, Signals & Systems","","",""
"uuid:c408e496-937f-44b2-a76f-a6cc4d905986","http://resolver.tudelft.nl/uuid:c408e496-937f-44b2-a76f-a6cc4d905986","Size Effect in the Compression of 3D Polymerized Micro-Structures","Li, Jiayu (Dalian University of Technology); Accardo, A. (TU Delft Micro and Nano Engineering); Liu, Shutian (Dalian University of Technology)","","2024","Micro/nanoscale additive manufacturing provides a powerful tool for advanced materials and structures with complex and precise features. For instance, the feature resolution of two-photon polymerization (2PP) can reach 200 nm. At this scale, materials properties can change, and the influence of the size effect cannot be ignored. Therefore, it is necessary to assess changes in the material mechanical properties considering size effects. In this work, several micrometric polymeric specimens are printed via 2PP, and their mechanical properties are assessed using compression tests. Detailed printing and testing procedures and the effects of parameter settings are provided. The experimental results show that the changes in the microstructures size have a direct effect on Young s modulus. In particular, a large surface-volume ratio results in a higher Young s modulus. In other words, the smaller the structure size, the higher the stiffness. The reported findings play a significant role in the development of fabrication strategies for polymeric microstructures where high stiffness accuracy is fundamental.","mechanical properties of materials; micro/nanoscale additive manufacturing; Size effect; two-photon polymerization resin; Young s modulus","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-25","","","Micro and Nano Engineering","","",""
"uuid:a23a5214-0c2a-4672-85ac-755681604b5d","http://resolver.tudelft.nl/uuid:a23a5214-0c2a-4672-85ac-755681604b5d","A Bayesian defect-based physics-guided neural network model for probabilistic fatigue endurance limit evaluation","Tognan, A. (Università degli Studi di Udine); Patanè, Andrea (Trinity College Dublin); Laurenti, L. (TU Delft Team Luca Laurenti); Salvati, Enrico (Università degli Studi di Udine)","","2024","Accurate fatigue assessment of material plagued by defects is of utmost importance to guarantee safety and service continuity in engineering components. This study shows how state-of-the-art semi-empirical models can be endowed with additional defect descriptors to probabilistically predict the occurrence of fatigue failures by exploiting advanced Bayesian Physics-guided Neural Network (B-PGNN) approaches. A B-PGNN is thereby developed to predict the fatigue failure probability of a sample containing defects, referred to a given fatigue endurance limit. In this framework, a robustly calibrated El Haddad's curve is exploited as the prior physics reinforcement of the probabilistic model, i.e., prior knowledge. Following, a likelihood function is built and the B-PGNN is trained via Bayesian Inference, thus calculating the posterior of the parameters. The arbitrariness of the choice of the related architecture is circumvented through a Bayesian model selection strategy. A case-study is analysed to prove the robustness of the proposed approach. This methodology proposes an advanced practical approach to help support the probabilistic design against fatigue failure.","Additive manufacturing; Bayesian Physics-guided Neural Networks; Defects; Fatigue strength; Uncertainty quantification","en","journal article","","","","","","","","","","","Team Luca Laurenti","","",""
"uuid:89f6c689-7b58-4fbb-ae6a-e48be3722d19","http://resolver.tudelft.nl/uuid:89f6c689-7b58-4fbb-ae6a-e48be3722d19","Finlet rails for the reduction of the trailing-edge noise","Fiscaletti, D. (TU Delft Wind Energy); Lima Pereira, L.T. (TU Delft Wind Energy); Ragni, D. (TU Delft Wind Energy)","","2024","The present study focuses on the application of finlet rails as a passive technique of flow control to mitigate trailing-edge noise. Finlet rails are small cylinders whose axes are aligned along the streamwise direction, transversally positioned with respect to the trailing edge. In the first part of this study, the effects of finlet geometry on the aeroacoustic emission of a NACA 633−018 airfoil are investigated using an array of microphones. It is observed that reducing the transversal spacing of finlet rails leads to increasing the maximum noise reduction, found to be of 4 decibels at relatively low frequencies. An optimum for the height of the finlets was determined, equivalent to 1.6δ∗, where δ∗ is the displacement thickness of the boundary layer. With the aim of unveiling the underlying physical mechanism for finlet rails, PIV at high spatial resolution is applied around the surface treatment. It is found that the turbulence energy is lifted-up and moved away from the scattering edge, which attenuates the wall-pressure fluctuations. The observed attenuation of the wall-pressure fluctuations occurs at the energy-containing scales, which is an important difference with finlet fences. In the region underneath the finlet rails, the transversal size of the energetic structures diminishes when the surface treatment is applied. The combination of the lift-up of the turbulence structures, that reduces the wall-pressure fluctuations, with the smaller turbulence scales is responsible for the noise reduction observed for finlet rails.","Finlet rails; Particle image velocimetry; Trailing-edge noise","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:67246fb8-d0c7-4dde-b931-541656d0e860","http://resolver.tudelft.nl/uuid:67246fb8-d0c7-4dde-b931-541656d0e860","Lp-estimates for the square root of elliptic systems with mixed boundary conditions II","Bechtel, S. (TU Delft Analysis)","","2024","We show Lp-estimates for square roots of second order complex elliptic systems L in divergence form on open sets in Rd subject to mixed boundary conditions. The underlying set is supposed to be locally uniform near the Neumann boundary part, and the Dirichlet boundary part is Ahlfors–David regular. The lower endpoint for the interval where such estimates are available is characterized by p-boundedness properties of the semigroup generated by −L, and the upper endpoint by extrapolation properties of the Lax–Milgram isomorphism. Also, we show that the extrapolation range is relatively open in (1,∞).","Calderón–Zygmund decomposition for Sobolev functions; Complex elliptic systems of second order; Hardy's inequality; Kato square root problem; Lax–Milgram isomorphism; Mixed boundary conditions","en","journal article","","","","","","","","","","","Analysis","","",""
"uuid:b4cad563-1247-489d-8146-cb2a74060fb0","http://resolver.tudelft.nl/uuid:b4cad563-1247-489d-8146-cb2a74060fb0","On automated model discovery and a universal material subroutine for hyperelastic materials","Peirlinck, M. (TU Delft Medical Instruments & Bio-Inspired Technology); Linka, Kevin (Stanford University); Hurtado, Juan A. (Dassault Systèmes); Kuhl, Ellen (Stanford University)","","2024","Constitutive modeling is the cornerstone of computational and structural mechanics. In a finite element analysis, the constitutive model is encoded in the material subroutine, a function that maps local strains onto stresses. This function is called within every finite element, at each integration point, within every time step, at each Newton iteration. Today's finite element packages offer large libraries of material models to choose from. However, the scientific criteria for appropriate model selection remain highly subjective and prone to user bias. Here we fully automate the process of model selection, autonomously discover the best model and parameters from experimental data, encode all possible discoverable models into a single material subroutine, and seamlessly integrate this universal material subroutine into a finite element analysis. We prototype this strategy for incompressible, isotropic, hyperelastic soft matter systems that we characterize through a combination of twelve possible terms. These terms feature the first and second invariants, raised to the first and second powers, embedded in the identity, exponential, and logarithmic functions, generating 22×2×3= 4096 models in total. We demonstrate how to integrate these models into a single universal material subroutine that features the classical neo Hooke, Blatz Ko, Mooney Rivlin, Demiray, Gent, and Holzapfel models as special cases. Finite element simulations with our new universal material subroutine show that it specializes well to these widely used models, generalizes well to newly discovered models, and agrees excellently with both experimental data and previous simulations. It also performs well within realistic finite element simulations and accurately predicts stress concentrations in the human brain for six different head impact scenarios. We anticipate that integrating automated model discovery into a universal material subroutine will generalize naturally to more complex compressible, anisotropic, inelastic materials and to other nonlinear finite element platforms. Replacing dozens of individual material subroutines by a single universal material subroutine that is populated directly via automated model discovery – entirely without human interaction – makes finite element analyses more accessible, more robust, and less vulnerable to human error. This could forever change how we simulate materials and structures. Our source code, data, and examples are available at https://github.com/LivingMatterLab.","Automated model discovery; Constitutive modeling; Constitutive neural networks; Hyperelasticity; Material subroutine","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-17","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:53f5717c-d13d-4b44-a7da-498d6d2b7c6d","http://resolver.tudelft.nl/uuid:53f5717c-d13d-4b44-a7da-498d6d2b7c6d","A near-linear kernel for bounded-state parsimony distance","Deen, Elise (Student TU Delft); van Iersel, L.J.J. (TU Delft Discrete Mathematics and Optimization); Janssen, Remie (Rijksinstituut voor Volksgezondheid en Milieu (RIVM)); Jones, M.E.L. (TU Delft Discrete Mathematics and Optimization); Murakami, Yukihiro (TU Delft Discrete Mathematics and Optimization); Zeh, Norbert (Dalhousie University)","","2024","The maximum parsimony distance dMP(T1,T2) and the bounded-state maximum parsimony distance dMPt(T1,T2) measure the difference between two phylogenetic trees T1,T2 in terms of the maximum difference between their parsimony scores for any character (with t a bound on the number of states in the character, in the case of dMPt(T1,T2)). While computing dMP(T1,T2) was previously shown to be fixed-parameter tractable with a linear kernel, no such result was known for dMPt(T1,T2). In this paper, we prove that computing dMPt(T1,T2) is fixed-parameter tractable for all t. Specifically, we prove that this problem has a kernel of size O(klgk), where k=dMPt(T1,T2). As the primary analysis tool, we introduce the concept of leg-disjoint incompatible quartets, which may be of independent interest.","Distance measure; Kernelization; Maximum parsimony distance; Parameterized complexity; Parsimony; Phylogenetic tree; Phylogenetics","en","journal article","","","","","","","","","","","Discrete Mathematics and Optimization","","",""
"uuid:c7ecc30c-ae74-427f-a26d-628a78fc092c","http://resolver.tudelft.nl/uuid:c7ecc30c-ae74-427f-a26d-628a78fc092c","Orienting undirected phylogenetic networks","Huber, Katharina T. (University of East Anglia); van Iersel, L.J.J. (TU Delft Discrete Mathematics and Optimization); Janssen, R. (TU Delft Discrete Mathematics and Optimization); Jones, M.E.L. (TU Delft Discrete Mathematics and Optimization); Moulton, V.L. (TU Delft Discrete Mathematics and Optimization; University of East Anglia); Murakami, Yukihiro (TU Delft Discrete Mathematics and Optimization); Semple, Charles (University of Canterbury)","","2024","This paper studies the relationship between undirected (unrooted) and directed (rooted) phylogenetic networks. We describe a polynomial-time algorithm for deciding whether an undirected nonbinary phylogenetic network, given the locations of the root and reticulation vertices, can be oriented as a directed nonbinary phylogenetic network. Moreover, we characterize when this is possible and show that, in such instances, the resulting directed nonbinary phylogenetic network is unique. In addition, without being given the location of the root and the reticulation vertices, we describe an algorithm for deciding whether an undirected binary phylogenetic network N can be oriented as a directed binary phylogenetic network of a certain class. The algorithm is fixed-parameter tractable (FPT) when the parameter is the level of N and is applicable to classes of directed phylogenetic networks that satisfy certain conditions. As an example, we show that the well-studied class of binary tree-child networks satisfies these conditions.","Characterization; Computational biology; Fixed-parameter tractability; Graph algorithm; Graph orientation; Phylogenetic network; Phylogenetics; Polynomial-time algorithm","en","journal article","","","","","","","","","","","Discrete Mathematics and Optimization","","",""
"uuid:c75c9694-0dcf-4dc3-becb-f20e00e4d248","http://resolver.tudelft.nl/uuid:c75c9694-0dcf-4dc3-becb-f20e00e4d248","A shared PV system for transportation and residential loads to reduce curtailment and the need for storage systems","Diab, I. (TU Delft DC systems, Energy conversion & Storage); Damianakis, Nikolaos (TU Delft DC systems, Energy conversion & Storage); Chandra Mouli, G.R. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2024","This paper proposes a shared multi-stakeholder PV system for traction substations and nearby residential loads to reduce the need for storage, AC grid exchange, and curtailment. The residential stakeholders offer both the base electrical load and the solar panels installation space needed by the traction stakeholder, who brings the peak load and investments to the former. Two case studies were conducted for one year in the city of Arnhem, The cy=Netherlands, using comprehensive and verified simulation models: A high-traffic and a low-traffic substation. The results showed a positive, synergetic benefit in reducing the PV system's excess energy and size requirement for any type of traction substations connected to any number of households. In one detailed example, the multi-stakeholder system suggested in this paper is shown to reduce curtailment by up to 80% in moments of zero-traction load. Generally, the direct load coverage of a PV system is increased by as much as 7 absolute percentage points to the single-stakeholder system when looking at energy-neutral system sizes. This multi-stakeholders system offers then an increase in the techno-economic feasibility of PV system integration in urban loads.","DC systems; Electric mobility; Public transport; Smart grids; Solar PV; Trolleybus","en","journal article","","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:ffa48f05-6e56-4a77-9d2e-d1854e046f3f","http://resolver.tudelft.nl/uuid:ffa48f05-6e56-4a77-9d2e-d1854e046f3f","Carbon Design Bottlenecks: An Empirical Taxonomy Of The Challenges Integrating Carbon Data In The Architecture Practice","Veloso e Zárate, H. (TU Delft Building Knowledge); Triggianese, M. (TU Delft Building Knowledge); Cuartero, Javier (KAAN Architecten); Stoter, J.E. (TU Delft Urban Data Science); Gilio, Renata (KAAN Architecten)","","2024","With the growing demand for sustainable accountability, the European Directive 2014/24/EU (EU 2014) pushes architects to deliver Building Information Models (BIM) as a part of procurement processes for public buildings. In the Netherlands, BIM model data is relevant to the building permitting process, which involves an environmental performance calculation (MPG). This assessment takes into consideration the embodied carbon of materials in a building. Although this analysis is performed by a qualified expert in late design phases, architects benefit from integrating carbon data in early design decision-making. Design methods supported by Life Cycle Assessment (LCA) values are needed before involving expert collaborators, and not only when applying for a building permit. The existing carbon assessment tools require detailed data from BIM models, which are often not available at early design phases. Simplified tools have been discussed in theory, and explored in their potential applications, however, there lacks scientific literature discussing the hurdles designers face in their attempt to create such tools in practice, for their internal use throughout early design phases. This paper focuses on the architecture professional practice and design methods supported by digital and computational technologies, regarding embodied carbon data. It investigates the challenges in integrating embodied carbon data in the design workflow, through the development of a digital tool made by designers, for designers. This paper conducts an empirical investigation within a Rotterdam-based architecture office, with a broad portfolio in BIM usage and public building projects, to identify and categorize the factors affecting carbon data integration into the design workflows. It proposes a taxonomy of challenges within the architecture office, to better communicate the designer's needs to the data providers and software developers with architects as a target user. Amongst the bottlenecks encountered are: access to data (data inclusiveness), data literacy and connecting data usage with design decision-making.","","en","conference paper","ACSA Press","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-01","","","Building Knowledge","","",""
"uuid:e4f173b9-f95e-4458-8c96-10f18c202ed9","http://resolver.tudelft.nl/uuid:e4f173b9-f95e-4458-8c96-10f18c202ed9","Automated Map Generalization: Emerging Techniques and New Trends (Editorial)","Zhang, Xiang (Sun Yat-sen University); Touya, Guillaume (Université Gustave Eiffel; IGN; École nationale des sciences géographiques (ENSG)); Meijers, B.M. (TU Delft Digital Technologies)","","2024","Automated map generalization has been a major area of research for decades but has still not reached maturity. Besides the needs for more adaptive algorithms, a fundamental question remains: How can we transfer human generalization knowledge into a computational system more effectively? Previous efforts do not seem capable to fully overcome the “knowledge acquisition bottleneck.” As new theories and technologies emerged in artificial intelligence (particularly deep learning), computers are now able to tackle human-level tasks with superior performance, showing great potential in automated generalization. Meanwhile, crowdsourced geographic information and social sensing is growing at an increasing speed, and the needs for visualizing and analyzing massive geo-referenced data at various scales are numerous. It is therefore necessary to adapt map generalization to these fields. This highlights the potential of applying map generalization in the visual, interactive, and exploratory analysis of abstract (e.g., hierarchical relations) and physical (e.g., movement trajectories) data. This topical collection brings six contributions reporting recent progress and trends in automated generalization in various aspects mentioned above, with which we hope to trigger further discussion and research in our field with new ideas and methodologies.","Deep learning; Map generalization; Visualization","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-27","","","Digital Technologies","","",""
"uuid:123ab14c-6d68-451c-aece-552e93200be2","http://resolver.tudelft.nl/uuid:123ab14c-6d68-451c-aece-552e93200be2","Influence of Installation Method on the Axial Capacity of Piles in Very Dense Sand","Duffy, K. (TU Delft Geo-engineering); Gavin, Kenneth (TU Delft Geo-engineering); Korff, M. (TU Delft Geo-engineering); de Lange, Dirk (Deltares); Roubos, Alfred (Port of Rotterdam Authority)","","2024","Three driven precast, four driven cast-in-situ, and four screw injection piles were installed and tested in dense to very dense sand at a site in the Netherlands. Each pile was instrumented with two types of fiber optic sensors and tested under axial compression. Through these tests, a comparison could be made of how different installation methods influence the pile base and shaft response. For example, large residual base stresses were measured in the driven precast piles after installation. Of the three pile types tested, the driven precast piles also reached the highest base stresses, mobilizing their full base resistance at comparatively low displacements. The base response of the driven cast-in-situ piles was also like that of a driven precast pile with residual stresses excluded. In contrast, the screw injection piles mobilized much lower ultimate base resistances and with a much lower stiffness. In terms of shaft resistance, the precast piles showed friction fatigue effects in line with existing models, but this effect was not evident for the driven cast-in-situ or screw injection piles. Finally, shaft and base resistances measured in the dense to very dense sand layers were greater than limiting resistances prescribed in several design standards. By taking this into consideration in design standards, the results would help reduce some of the overconservatism present in design and consequently reduce the financial and environmental cost of pile manufacturing and installation.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-10-08","","","Geo-engineering","","",""
"uuid:cb898485-62a3-4c2c-8660-71cdff21542b","http://resolver.tudelft.nl/uuid:cb898485-62a3-4c2c-8660-71cdff21542b","A study of the non-linear properties and wave generation of the multi-layer non-hydrostatic wave model SWASH","Vasarmidis, Panagiotis (Universiteit Gent); Klonaris, Georgios (Universiteit Gent); Zijlema, Marcel (TU Delft Environmental Fluid Mechanics); Stratigaki, Vasiliki (Universiteit Gent); Troch, Peter (Universiteit Gent)","","2024","Despite the increasing use of non-hydrostatic models in the study of wave processes in coastal regions, there is still limited understanding of the non-linear properties of the governing equations and how they improve with increased vertical resolution. In this study, the governing equations of the non-hydrostatic wave model SWASH are analysed and the linear and non-linear solutions up to third-order of all dependent variables are derived, considering one to four vertical layers. The analysis concludes that the model can achieve excellent non-linear properties with respect to the Stokes theory over a large range of water depths using only a few vertical layers. Furthermore, deriving solutions for all variables enables the formulation of improved wave generation and absorption boundary conditions for non-hydrostatic models. A well-known issue of non-linear wave models is related to the generation and propagation of spurious free waves, resulting to non-homogeneous wave fields. In this study, it is proven that by imposing the derived exact mathematical solutions of the governing equations at the model's boundaries, the target first- and second-order wave profiles can be generated with high accuracy, while the spurious waves can be entirely eliminated.","Improved wave generation; Linear and non-linear properties; Non-hydrostatic model; Sub- and super-harmonics; SWASH","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-27","","","Environmental Fluid Mechanics","","",""
"uuid:caf992b4-8518-42af-bfae-9d3e59158698","http://resolver.tudelft.nl/uuid:caf992b4-8518-42af-bfae-9d3e59158698","On mixtures as working fluids of air-cooled ORC bottoming power plants of gas turbines","Krempus, D. (TU Delft Flight Performance and Propulsion); Bahamonde, Sebastian; van der Stelt, T.P. (TU Delft Flight Performance and Propulsion; Asimptote bv); Klink, Wolfgang (Corporate Technology); Colonna, Piero (TU Delft Flight Performance and Propulsion); de Servi, C.M. (TU Delft Flight Performance and Propulsion; Flemish Institute for Technological Research)","","2024","The use of mixtures as working fluids of organic Rankine cycle (ORC) waste heat recovery (WHR) power plants has been proposed in the past to improve the matching between the temperature profile of the hot and the cold streams of condensers and evaporators, thus to possibly increase the energy conversion efficiency of the system. The goal of this study is to assess the benefits in terms of efficiency, environmental (GWP) and operational safety (flammability) that can be obtained by selecting optimal binary mixtures as working fluids of air-cooled ORC bottoming power plants of medium-capacity industrial gas turbines. Furthermore, two thermodynamic cycle configurations are analyzed, namely the simple recuperated cycle and the so-called split-cycle configurations. The benchmark case is a combined cycle power plant formed by an industrial gas turbine and an air-cooled recuperated ORC power unit with cyclopentane as the working fluid. The results of this study indicate that binary mixtures provide the designer with a wider choice of optimal working fluids, however, in the case of the recuperated-cycle configuration, no improvement in terms of combined cycle efficiency over the benchmark case can be achieved. The split-cycle configuration leads to an increase of combined cycle efficiency of the order of 1.5%, both in case of pure and blended working fluids. Furthermore, for this cycle configuration the use of Novec 649 as working fluid is advantageous because it is environmentally and operationally safe, and it does not involve any penalty in terms of combined cycle efficiency if compared to the benchmark case. Additionally, the use of this fluid would lead to a more compact turbine, as the corresponding thermodynamic cycle would determine a turbine volume flow ratio that is half of the value of the benchmark case and a specific enthalpy difference over the expansion that is one fifth.","Binary mixtures; Organic Rankine cycle; Waste heat recovery","en","journal article","","","","","","","","","","","Flight Performance and Propulsion","","",""
"uuid:accf47a3-38dd-4b1e-827e-b5ec20991b39","http://resolver.tudelft.nl/uuid:accf47a3-38dd-4b1e-827e-b5ec20991b39","An analytical framework for the best–worst method","Wu, W. (TU Delft Transport and Logistics; Anhui University; Southeast University); Liu, Xinwang (Southeast University); Zhou, Ligang (Anhui University); Qin, Jindong (Wuhan University of Technology); Rezaei, J. (TU Delft Transport and Logistics)","","2024","Since the development of the best–worst method (BWM) in 2015, it has become a popular research focus in multi-criteria decision-making. The original optimization problem of the BWM is a nonlinear min–max model that can lead to multiple optimal solutions, while the linear model of the BWM produces a unique solution. The two models need to be solved by optimization software packages. In addition, although the linear model of the BWM can obtain a unique solution, it produces different feasible regions than the nonlinear model of the BWM, and it changes the objective function. This study aims to solve the nonlinear model of the BWM mathematically to obtain the analytical forms of the optimal solutions. First, we transform the original nonlinear model of BWM into an equivalent optimization model driven by the optimally modified comparison vectors. The equivalent BWM provides a solid basis for computing the analytical solutions. Second, for not-fully consistent pairwise comparison systems, we strictly prove that there is only one unique optimal solution with three criteria, and there might be multiple optimal solutions with more than three criteria. We further develop the analytical forms of these unique and multiple optimal solutions and the optimal interval weights. Third, we develop a secondary objective function to select a unique solution for the BWM. The secondary objective function retains all the characteristics of the original nonlinear model of the BWM, and we find the unique solution analytically. Finally, some numerical examples are examined, and a comparative analysis is performed to demonstrate the effectiveness of our analytical solution approach.","Analytical solutions; Best–worst method (BWM); Multi-criteria decision-making; Multiple optimal solutions","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-25","","","Transport and Logistics","","",""
"uuid:1f60409e-4439-45be-ace1-1a9bc05a1812","http://resolver.tudelft.nl/uuid:1f60409e-4439-45be-ace1-1a9bc05a1812","Scale-free percolation mixing time","Cipriani, A. (TU Delft Applied Probability); Salvi, Michele (University of Rome Tor Vergata)","","2024","Assign to each vertex of the one-dimensional torus i.i.d. weights with a heavy-tail of index τ−1>0. Connect then each couple of vertices with probability roughly proportional to the product of their weights and that decays polynomially with exponent α>0 in their distance. The resulting graph is called scale-free percolation. The goal of this work is to study the mixing time of the simple random walk on this structure. We depict a rich phase diagram in α and τ. In particular we prove that the presence of hubs can speed up the mixing of the chain. We use different techniques for each phase, the most interesting of which is a bootstrap procedure to reduce the model from a phase where the degrees have bounded averages to a setting with unbounded averages.","Degree distribution; Mixing time; Random graph; Scale-free percolation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-29","","","Applied Probability","","",""
"uuid:cb58d59e-76f7-469b-bfb8-49b38d148237","http://resolver.tudelft.nl/uuid:cb58d59e-76f7-469b-bfb8-49b38d148237","Compact Housing for Incremental Growth: The K206 RDP Project in Alexandra, Johannesburg","Wilcox, A.Y. (TU Delft Urban Development Management); Mota, Nelson (TU Delft Space & Type); Haffner, M.E.A. (TU Delft Urban Development Management); Elsinga, M.G. (TU Delft Urban Development Management)","","2024","The South African Reconstruction and Development Programme (RDP) was initiated to provide subsidised housing for low‐income families. However, the programme faced challenges in establishing adequate technical guidelines and standards, resulting in subpar housing quality. This article discusses the multifaceted nature of subsidised housing design, emphasising the importance of incorporating technical housing standards as well as the spatial needs of residents based on their context (at both domestic and neighbourhood scales). The article focuses on the K206 housing RDP project in Alexandra, Johannesburg, as a case study that transitioned from generic technical standards to a resident‐responsive design scheme that was inspired by the backyard room incremental expansions that were already prevalent in the Alexandra context. A critical review of South Africa’s RDP housing design technical standards and policy is explored. The article also examines the density standards and allowances for incremental expansions introduced by the K206 project, analysing data derived from fieldwork observations, interviews, and the spatial analysis of 26 dwelling units. The study’s findings underscore the significance of maintaining an equilibrium between technical standards and resident‐responsive design decisions. The results demonstrate that tailoring the RDP housing design solutions to unique contextual needs can significantly elevate the quality of life of residents concerning income generation and flexibility for incremental expansion. However, this balance is delicate and disparities between the RDP technical standards and user‐initiated development over time also have the potential to ultimately impair residents’ living spaces.","incremental housing; reconstruction and development programme; South Africa; subsidised housing; technical norms; technical standards","en","journal article","","","","","","","","","","","Urban Development Management","","",""
"uuid:55e2a151-79c6-4c7b-9c67-adbde9d52773","http://resolver.tudelft.nl/uuid:55e2a151-79c6-4c7b-9c67-adbde9d52773","Knowledge sharing in manufacturing using LLM-powered tools: User study and model benchmarking","Kernan Freire, S. (TU Delft Internet of Things); Wang, C.W. (TU Delft Human-Centred Artificial Intelligence); Foosherian, Mina (BIBA – Bremer Institut für Produktion und Logistik GmbH); Wellsandt, Stefan (BIBA - Bremer Institut für Produktion und Logistik GmbH); Ruiz-Arenas, Santiago (Universidad EAFIT); Niforatos, E. (TU Delft Internet of Things)","","2024","Recent advances in natural language processing enable more intelligent ways to support knowledge sharing in factories. In manufacturing, operating production lines has become increasingly knowledge-intensive, putting strain on a factory's capacity to train and support new operators. This paper introduces a Large Language Model (LLM)-based system designed to retrieve information from the extensive knowledge contained in factory documentation and knowledge shared by expert operators. The system aims to efficiently answer queries from operators and facilitate the sharing of new knowledge. We conducted a user study at a factory to assess its potential impact and adoption, eliciting several perceived benefits, namely, enabling quicker information retrieval and more efficient resolution of issues. However, the study also highlighted a preference for learning from a human expert when such an option is available. Furthermore, we benchmarked several commercial and open-sourced LLMs for this system. The current state-of-the-art model, GPT-4, consistently outperformed its counterparts, with open-source models trailing closely, presenting an attractive option given their data privacy and customization benefits. In summary, this work offers preliminary insights and a system design for factories considering using LLM tools for knowledge management.","natural language interface; benchmarking; Large Language Models; factory; industrial settings; industry 5.0; knowledge sharing; information retrieval","en","journal article","","","","","","","","","","","Internet of Things","","",""
"uuid:c4b6f7f0-8d49-4e9e-8545-3c0c7bfb72ca","http://resolver.tudelft.nl/uuid:c4b6f7f0-8d49-4e9e-8545-3c0c7bfb72ca","The future of digitalized project practices through data-savvy talent: A digital competence formation perspective","Liu, Yan (Nanjing University); Zeng, Ningshuang (Southeast University); Papadonikolaki, E. (TU Delft Integral Design & Management); Maritshane, Kirk (Harrow, Richmond, and Uxbridge Colleges (HRUC)); Chan, P.W.C. (TU Delft Design & Construction Management)","","2024","Amidst the disruptive backdrop of the COVID-19 pandemic, organizations are navigating toward a new normal, leveraging digital technologies to reconfigure business processes and operational practices. This study delves into the transformative effects of digitalization on project management, with a focus on integrating data-savvy talent in a data-rich era. Employing a mixed methods approach, data were collected from June to November 2022, providing a comprehensive blend of various perspectives. Quantitative and qualitative methods were adopted successively in this study to explore the formation mechanism of digital competence of talents in project management and analyze the practical experience and expectations on the impact of data-savvy talents on project management. This study highlights the crucial role of organizations in actively shaping digital competencies to align with the changing demands of project management. It also emphasizes the increasing importance of data-savvy talents, whose intrinsic understanding of digital technologies and business models is essential in transforming the project management landscape. The outcomes of this study offer both theoretical insights into the nexus of digital competence, talent management, and project management, and practical guidelines for effectively integrating new talents into project management practices.","digital transformation; project management professionals; talent management; new talents; structural equation modeling","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:8a329fbb-cc12-4fb2-a9f0-7412c8f039c4","http://resolver.tudelft.nl/uuid:8a329fbb-cc12-4fb2-a9f0-7412c8f039c4","Publisher Correction: Firn on ice sheets (Nature Reviews Earth & Environment, (2024), 5, 2, (79-99), 10.1038/s43017-023-00507-9)","Amory, Charles (Université Grenoble Alpes); Buizert, Christo (Oregon State University); Buzzard, Sammie (Cardiff University; University of Northumbria); Case, Elizabeth (Columbia University); Clerx, Nicole (University of Fribourg); Culberg, Riley (Cornell University); Lhermitte, S.L.M. (TU Delft Mathematical Geodesy and Positioning; Katholieke Universiteit Leuven); de Roda Husman, S. (TU Delft Physical and Space Geodesy); Wouters, B. (TU Delft Physical and Space Geodesy)","","2024","In the version of the article initially published, in Fig. 5, under “Radar altimeter”, “O(16–160 m)” previously read “O(16–160 km)”. This has now been corrected in the HTML and PDF versions of the article.","","en","journal article","","","","","","","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:9beab0e5-fd2d-4541-96ce-1a8cf29a85e7","http://resolver.tudelft.nl/uuid:9beab0e5-fd2d-4541-96ce-1a8cf29a85e7","The utilization of ghost reflections retrieved by seismic interferometry for layer-specific characterization of the shallow subsurface","Shirmohammadi, F. (TU Delft Applied Geophysics and Petrophysics); Draganov, D.S. (TU Delft Applied Geophysics and Petrophysics); Ghose, R. (TU Delft Applied Geophysics and Petrophysics)","","2024","Seismic interferometry (SI) retrieves the Green function between two receiver locations using their recordings from a boundary of sources. When using sources and receivers only at the surface, the virtual-source gathers retrieved by SI contain pseudo-physical reflections as well as ghost (non-physical) reflections. These ghost reflections are the results of the cross-correlation or auto-correlation (AC) of primary reflections from two different depth levels, and they contain information about the seismic properties of specific layers in the subsurface. We investigated the application of ghost reflections for layer-specific characterization of the shallow subsurface using SI by AC. First, we showed the technique's potential using synthetic data for a subsurface model with a lateral change in velocity, a gradient in depth for velocity, a thickness change and a velocity change of the target layer. Then, we applied the technique to shallow subsurface field data. We also focused on improving the retrieval of ghost reflections by removing the free-surface multiples and muting undesired events in active-source gathers before applying SI. Our results demonstrate that the ghost reflections can be used advantageously to characterize the layer that causes them to appear in the results of SI. Consequently, they can also provide valuable information for imaging and monitoring shallow subsurface structures.","imaging; reflection; S-wave; seismic; velocity","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:35e85fa6-9f60-4c22-9253-495b2baeb0f9","http://resolver.tudelft.nl/uuid:35e85fa6-9f60-4c22-9253-495b2baeb0f9","First - Principles study of hydrogen - Carbide interaction in bcc Fe","Sagar, S. (TU Delft Team Poulumi Dey); Sluiter, M.H.F. (TU Delft Team Marcel Sluiter); Dey, P. (TU Delft Team Poulumi Dey)","","2024","Rapid developments in the field of hydrogen energy have prompted the need for safe and efficient hydrogen transportation and storage. Steels form the backbone of the current energy infrastructure and thus offer a fast and cost-effective solution. Their excellent mechanical properties are attributed to the underlying microstructure which comprises of finely dispersed nano-precipitates. However, one major factor restricting their application is their susceptibility to Hydrogen Embrittlement (HE). In the past decade, experimental and theoretical works have been carried out to understand if the nano-sized carbides can aid in reducing the susceptibility to HE along with providing strengthening. Within this ab-inito study, we investigated the effectiveness of fully coherent nano-carbides (i.e. TiC, VC and NbC) to limit the diffusible hydrogen content in bcc Fe. Our study revealed that the interplay between hydrogen and carbon vacancies, local atomic environment at interface as well as elastic strain fields at the interface can lead to significantly increased hydrogen solubilities. While in TiC, the deepest traps were found to be in the bulk of carbides, in VC and NbC, the elastic strain fields around the interface led to the strongest trapping. Further, the formation of a two-hydrogen-vacancy complex was found to be favourable in VC. Finally, the migration barriers for hydrogen trapping in bulk TiC as well as across the Fe/TiC coherent interface indicate that these deep traps in the form of carbon vacancies are fairly accessible.","Density functional theory; Hydrogen embrittlement; Hydrogen trapping; Migration barriers; Transition metal carbides","en","journal article","","","","","","","","","","","Team Poulumi Dey","","",""
"uuid:6c51424d-93f1-445e-ba94-6640116ec968","http://resolver.tudelft.nl/uuid:6c51424d-93f1-445e-ba94-6640116ec968","Topology optimization of differentiable microstructures","Zhai, X. (TU Delft Materials and Manufacturing; University of Science and Technology of China); Wang, Weiming (The University of Manchester); Chen, Falai (University of Science and Technology of China); Wu, J. (TU Delft Materials and Manufacturing)","","2024","Recent years have seen a growing interest in topology optimization of functionally graded microstructures, characterized by an array of microstructures with varying volume fractions. However, microstructures optimized at slightly different volume fractions do not necessarily connect well when placed adjacently. Furthermore, optimization is commonly performed on a finite set of volume fractions, limiting the number of microstructure configurations. In this paper, we introduce the concept of differentiable microstructures, which are parameterized microstructures that exhibit continuous variations in both geometry and mechanical properties. To construct such microstructures, we propose a novel formulation for topology optimization. In this approach, a series of 2-dimensional microstructures is represented using a height field, and the objective is to maximize the bulk modulus of the entire series. Through this optimization process, an initial microstructure with a small volume fraction undergoes non-uniform transformations, generating a series of microstructures with progressively increasing volume fractions. Notably, when compared to traditional uniform morphing methods, our proposed optimization approach yields a series of microstructures with bulk moduli that closely approach the theoretical limit.","Functionally graded microstructures; Inverse homogenization; Topology optimization","en","journal article","","","","","","","","","","","Materials and Manufacturing","","",""
"uuid:cad1561d-a3fb-4ed7-8856-6693571ec656","http://resolver.tudelft.nl/uuid:cad1561d-a3fb-4ed7-8856-6693571ec656","Magnetic Field Prediction in Cubic Spoke-Type Permanent-Magnet Machine Considering Magnetic Saturation","Du, Yunlu (Southeast University); Huang, Yunkai (Southeast University); Guo, Baocheng (Nanjing Normal University); Djelloul-Khedda, Zakarya (Université Djilali Bounaama Khemis Miliana); Peng, Fei (Southeast University); Yao, Y. (TU Delft DC systems, Energy conversion & Storage; Southeast University); Dong, J. (TU Delft DC systems, Energy conversion & Storage)","","2024","In this article, a nonlinear semianalytical model (SAM) is presented to predict the magnetic field distribution (MFD) and electromagnetic performances (EPs) in the cubic spoke-type permanent magnet (PM) machine. To model the rectangular PMs, the rectangular PM is simplified as a combination of fan-shaped regions with different arc angles. Then, the MFD and EPs of the cubic spoke-type machines can be obtained by the harmonic modeling technique. Particularly, the saturation of the magnetic bridges is considered by the nonlinear iterative algorithm. The proposed nonlinear SAM is studied on a 12-slot/8-pole cubic PM prototype, and the nonlinear finite element model and experiment verify its correctness. The main contribution of this article is to present a general analytical modeling method for cubic spoke-type PM machines and consider the magnetic saturation of magnetic bridges.","Cubic spoke-type permanent magnet (PM) machine; harmonic modeling (HM); magnetic saturation; nonlinear","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-08","","","DC systems, Energy conversion & Storage","","",""
"uuid:2831b2e7-f892-488f-a698-22661f3ea034","http://resolver.tudelft.nl/uuid:2831b2e7-f892-488f-a698-22661f3ea034","Modelling of kinematic higher pairs by lower pairs","Meijaard, J.P. (TU Delft Mechatronic Systems Design)","","2024","Kinematic joints are classified in lower pairs and higher pairs. Most multibody modelling techniques focus on lower pairs, because a complete classification in six types is available. Higher pairs are more diverse. In this article, higher pairs that can be exactly modelled by lower pairs are investigated. A complete classification of higher pairs that can be modelled by a chain of five single-degree-of-freedom lower pairs with a central revolute joint at the contact point is proposed. Two-dimensional cases and surfaces with discontinuities are also considered. The equivalent chains can be used for exact and approximate modelling of higher pairs and as design alternatives. Illustrative examples and applications to a bicycle on toroidal wheels and a railway wheelset on a roller rig are shown.","Bicycle; Classification; Higher pairs; Kinematic joints; Lower pairs; Railway wheelset","en","journal article","","","","","","","","","","","Mechatronic Systems Design","","",""
"uuid:db86c1e3-26ca-4aa9-bd65-2008ac503c18","http://resolver.tudelft.nl/uuid:db86c1e3-26ca-4aa9-bd65-2008ac503c18","Land surface modeling informed by earth observation data: toward understanding blue–green–white water fluxes in High Mountain Asia","Buri, Pascal (Swiss Federal Institute for Forest, Snow and Landscape Research); Fatichi, Simone (National University of Singapore); Shaw, Thomas E. (Swiss Federal Institute for Forest, Snow and Landscape Research; Institute of Science and Technology Austria); Fyffe, Catriona L. (Institute of Science and Technology Austria); Miles, Evan S. (Swiss Federal Institute for Forest, Snow and Landscape Research); McCarthy, Michael J. (Swiss Federal Institute for Forest, Snow and Landscape Research); Kneib, Marin (Université Grenoble Alpes; University of Innsbruck); Ren, Shaoting (Chinese Academy of Sciences); Menenti, M. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences)","","2024","Mountains are important suppliers of freshwater to downstream areas, affecting large populations in particular in High Mountain Asia (HMA). Yet, the propagation of water from HMA headwaters to downstream areas is not fully understood, as interactions in the mountain water cycle between the cryo-, hydro- and biosphere remain elusive. We review the definition of blue and green water fluxes as liquid water that contributes to runoff at the outlet of the selected domain (blue) and water lost to the atmosphere through vapor fluxes, that is evaporation from water, ground, and interception plus transpiration (green) and propose to add the term white water to account for the (often neglected) evaporation and sublimation from snow and ice. We provide an assessment of models that can simulate the cryo-hydro-biosphere continuum and the interactions between spheres in high mountain catchments, going beyond disciplinary separations. Land surface models are uniquely able to account for such complexity, since they solve the coupled fluxes of water, energy, and carbon between the land surface and atmosphere. Due to the mechanistic nature of such models, specific variables can be compared systematically to independent remote sensing observations–providing vital insights into model accuracy and enabling the understanding of the complex watersheds of HMA. We discuss recent developments in spaceborne earth observation products that have the potential to support catchment modeling in high mountain regions. We then present a pilot study application of the mechanistic land surface model Tethys & Chloris to a glacierized watershed in the Nepalese Himalayas and discuss the use of high-resolution earth observation data to constrain the meteorological forcing uncertainty and validate model results. We use these insights to highlight the remaining challenges and future opportunities that remote sensing data presents for land surface modeling in HMA.","blue-green water; cryosphere-hydrosphere-biosphere continuum; glaciers; High Mountain Asia (HMA); high mountain water cycle; Land surface modeling; remote sensing; snow","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:c13e24b2-bb21-4c7d-9fdf-e8ceaa4d9617","http://resolver.tudelft.nl/uuid:c13e24b2-bb21-4c7d-9fdf-e8ceaa4d9617","Insights into sulfur and hydrogen sulfide induced corrosion of sintered nanocopper paste: A combined experimental and ab initio study","Chen, Wei (Fudan University); Liu, Xu (Fudan University); Yang, Zhoudong (Fudan University); Liu, X. (TU Delft Electronic Components, Technology and Materials); Hu, D. (TU Delft Electronic Components, Technology and Materials); Zhu, Xi (Fudan University; Research Institute of Fudan University, Ningbo); Fan, X. (Lamar University College of Engineering); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University; Research Institute of Fudan University, Ningbo)","","2024","The power semiconductor joining technology through sintering of copper nanoparticles is well-suited for die attachment in wide bandgap (WBG) semiconductors, offering high electrical, thermal, and mechanical performances. However, sintered nanocopper will be prone to degradation resulting from corrosion in sulfur-containing corrosive environments such as offshore areas. In this study, experiments, including aging test and corrosion characterization, and simulations based on density functional theory (DFT) studies were conducted to explore the corrosion behavior and mechanism of elemental sulfur (S8) and hydrogen sulfide (H2S) on sintered nanocopper. The experimental results indicated that loose corrosion products were observed on the sintered nanocopper during the ageing process involving S8, and compact layered corrosion products formed during the ageing process involving H2S. Furthermore, similar corrosion product compositions (Cu2O, Cu2S, CuO, CuS, and potentially Cu2SO4 or CuSO4) were observed in both the S8- and H2S-ageing processes. However, the S8-ageing process exhibited more noticeable corrosion penetration. This was explained in simulations results: the unsaturated Cu sites on the oxide layer [Cu2O(1 1 1)] of the sintered nanocopper could adsorb both H2S and S8, while the saturated Cu sites only exhibited the potential to adsorb S8.","Atmospheric corrosion; Density functional theory; Sintered nanocopper; Sulfur and hydrogen sulfide","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:08b57932-53a6-4565-a2aa-bbb6df0d615f","http://resolver.tudelft.nl/uuid:08b57932-53a6-4565-a2aa-bbb6df0d615f","Uncertainty analysis and interval prediction of LEDs lifetimes","Rocchetta, Roberto (Eindhoven University of Technology); Zhan, Zhouzhao (Eindhoven University of Technology); van Driel, W.D. (TU Delft Electronic Components, Technology and Materials; Signify); Di Bucchianico, Alessandro (Eindhoven University of Technology)","","2024","Lifetime analyses are crucial for ensuring the durability of new Light-emitting Diodes (LEDs) and uncertainty quantification (UQ) is necessary to quantify a lack of usable failure and degradation data. This work presents a new framework for predicting the lifetime of LEDs in terms of lumen maintenance, effectively quantifying the natural variability of lifetimes (aleatory) as well as the reducible uncertainty resulting from data scarcity (epistemic). Non-parametric survival models are employed for UQ of low-magnitude failures, while a new parametric interval prediction model (IPM) is introduced to characterize the uncertainty in high-magnitude lumen depreciation events and long-term extrapolated lifetimes. The width of interval-valued predictions reflects the inherent variability in degradation paths whilst the epistemic uncertainty, arising from data scarcity, is quantified by a statistical bound on the probability of the prediction errors for future degradation trajectories. A modified exponential flux decay model combined with the Arrhenius equation equips the IPM with physical information on the physics of LED luminous flux degradation. The framework is tested and validated on a novel database of LED degradation trajectories and in comparison to well-established probabilistic predictors. The results of this study support the validity of the proposed approach and the usefulness of the additional UQ capabilities.","Accelerated Degradation Data; Interval Prediction; Lifetime; Light-emitting Diodes; Lumen maintenance; Uncertainty Quantification","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-06","","","Electronic Components, Technology and Materials","","",""
"uuid:4ac82791-3ebc-42f0-9bf7-7d4ba888242d","http://resolver.tudelft.nl/uuid:4ac82791-3ebc-42f0-9bf7-7d4ba888242d","Role of thermodynamic relaxation on effectiveness of recycling agents on properties of aged bitumen","Ren, S. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering)","","2024","The low-temperature relaxation and fatigue cracking performance are two essential aspects in estimating the rejuvenation efficiency of recycling agents (RAs). This study aims to fundamentally investigate the effects of recycling agent type/dosage and aging degree of bitumen on thermodynamic and rheological properties of rejuvenated bitumen at low and intermediate temperatures. Molecular dynamics (MD) simulations are utilized to predict thermodynamic indices of rejuvenated bitumen, further linked to critical low-temperature and fatigue indicators from experiments. The results reveal that all RAs show a regeneration effect on fractional free volume (FFV), self-diffusion coefficient (DS), glass transition temperature (Tg), and surface free energy (γ). Bio-oil and engine-oil exhibit higher rejuvenation efficiency on these thermodynamic properties than naphthenic-oil and aromatic-oil. The aging degree of bitumen and temperature show significant effects on rejuvenation efficiency. It is recommended to use the FFV parameter to predict the relaxation properties of rejuvenated bitumen. However, these thermodynamic indicators inadequately differentiate between rejuvenators and softeners. Based on crossover parameter results, most recycling agents (bio-oil, engine oil, and naphthenic oil) in this study display softening characteristics. Only aromatic oil effectively rejuvenates the crossover modulus (Gc) of aged binder. Notably, engine oil demonstrates the least rejuvenation in crossover parameters for the recovery of aged bitumen. Further, γ demonstrates a strong association with both Glover-Rowe (G-R) and fatigue crack width C500 indices across all cases involving rejuvenated bitumen. This work will build a multi-scale evaluation framework on the rejuvenation effectiveness of recycling agents on low-temperature and fatigue performance of aged bitumen.","Rejuvenated bitumen; Molecular dynamic simulation; Low-temperature performance; Thermodynamic indicator; Multi-scale connection","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:2e40617a-6799-4465-9198-593821b408cd","http://resolver.tudelft.nl/uuid:2e40617a-6799-4465-9198-593821b408cd","The multi-dimensional challenges of controlling respiratory virus transmission in indoor spaces: Insights from the linkage of a microscopic pedestrian simulation and SARS-CoV-2 transmission model","Balkan, Büsra Atamer (Wageningen University & Research); Chang, You (Wageningen University & Research); Sparnaaij, M. (TU Delft Transport and Planning); Wouda, B.J. (TU Delft Game Lab); Boschma, D. (TU Delft Game Lab); Yuan, Y. (TU Delft Transport and Planning); Daamen, W. (TU Delft Transport and Planning); van Veen, A.J. (TU Delft Game Lab); Duives, D.C. (TU Delft Transport and Planning)","","2024","SARS-CoV-2 transmission in indoor spaces, where most infection events occur, depends on the types and duration of human interactions, among others. Understanding how these human behaviours interface with virus characteristics to drive pathogen transmission and dictate the outcomes of non-pharmaceutical interventions is important for the informed and safe use of indoor spaces. To better understand these complex interactions, we developed the Pedestrian Dynamics—Virus Spread model (PeDViS): an individual-based model that combines pedestrian behaviour models with virus spread models that incorporate direct and indirect transmission routes. We explored the relationships between virus exposure and the duration, distance, respiratory behaviour, and environment in which interactions between infected and uninfected individuals took place and compared this to benchmark ‘at risk’ interactions (1.5 metres for 15 minutes). When considering aerosol transmission, individuals adhering to distancing measures may be at risk due to build-up of airborne virus in the environment when infected individuals spend prolonged time indoors. In our restaurant case, guests seated at tables near infected individuals were at limited risk of infection but could, particularly in poorly ventilated places, experience risks that surpass that of benchmark interactions. Combining interventions that target different transmission routes can aid in accumulating impact, for instance by combining ventilation with face masks. The impact of such combined interventions depends on the relative importance of transmission routes, which is hard to disentangle and highly context dependent.","","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:0c9c2d11-84bb-4c47-a00b-bcd8642c648e","http://resolver.tudelft.nl/uuid:0c9c2d11-84bb-4c47-a00b-bcd8642c648e","A Novel Auction-Based Truck Appointment System for Marine Terminals","Parmaksizoglou, I.A. (TU Delft Air Transport & Operations); Bombelli, A. (TU Delft Air Transport & Operations); Sharpanskykh, Alexei (TU Delft Air Transport & Operations)","","2024","Background: Increased maritime trade has led to a surge in drayage operations, causing congestion and environmental issues in port areas. Truck Appointment Systems (TASs) are commonly used to manage truck arrival rates, yet transparency and equity in slot allocation remain problematic, fostering distrust between Licensed Motor Carriers (LMCs) and Marine Terminal Operators (MTOs). Methods: This study proposes a polycentric approach to improve truck scheduling and ensure that those impacted by decisions are involved in the decision-making process. A single-round auction mechanism focused on optimizing the truck hauling process through a pricing policy that promotes sincere bidding is introduced. The proposed approach employs an optimization strategy to achieve equitable coordination in truck synchronization through means of adaptable capacity management. Results: Numerical experiments assessing scenarios of noncollaborative behavior against partial collaboration between MTOs and LMCs demonstrate the effectiveness of the proposed approach in enhancing user satisfaction and terminal conditions for a case study focused on a medium-sized terminal. Collaboration between trucking companies is shown to increase utility per monetary unit spent on slot acquisition. Conclusions: The polycentric strategy offers a solution to TAS limitations by ensuring stakeholder participation with respect to flexibility and transparency by ensuring that those impacted by decisions are involved in the decision-making process.","truck appointment systems; auction; scheduling; collaboration; marine terminal operators","en","journal article","","","","","","","","","","","Air Transport & Operations","","",""
"uuid:86c90010-0373-436b-b63d-643279511778","http://resolver.tudelft.nl/uuid:86c90010-0373-436b-b63d-643279511778","Combining a daily temperature pattern analysis and a heat-pulse system to estimate sediment depths in sewer systems","Regueiro-Picallo, Manuel (Universidade da Coruña); Langeveld, J.G. (TU Delft Sanitary Engineering); Wei, Haoyu (Luleå University of Technology); Bertrand-Krajewski, Jean Luc (Université de Lyon); Rieckermann, Jörg (Swiss Federal Institute of Aquatic Science and Technology)","","2024","Sediments in urban drainage systems (UDS) significantly impact their operation, so effective strategies are required to reduce their negative effects. Monitoring sediment accumulation provides valuable insights into sediment characteristics, sediment transport dynamics, and system performance. However, the effectiveness of monitoring systems is limited due to cost constraints and installation challenges. This study describes the development and application of a new system based on temperature dynamics to measure sediment depths in sewer systems. The methodology involves the analysis of temperature time series under dry weather flow conditions to identify harmonic patterns between wastewater and sediment-bed temperatures. These patterns are increasingly attenuated by increasing sediment depth. This study combines a system called MONitoring Temperatures in SEdiments (MONTSE), which integrates a dual-probe heat-pulse (DPHP) method to characterize sediment thermal properties, and a surrogate model, which includes temperature pattern analysis, to estimate sediment depths. Likewise, laboratory-scale experiments were performed to validate the temperature monitoring system and the surrogate model performance. The maximum absolute errors in measured sediment depths were less than 22 mm, and the uncertainty of the system was estimated at ±7.3 mm. Groundbreaking measurements of thermal properties of UDS sediments were also reported. Reliable information on sediment depths and properties was provided, so the system could significantly optimize sewer system operation and cleaning strategies.","","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:ac261766-a741-48d5-8db3-018dbd0979fb","http://resolver.tudelft.nl/uuid:ac261766-a741-48d5-8db3-018dbd0979fb","The Simultaneous Model-Based Estimation of Joint, Muscle, and Tendon Stiffness is Highly Sensitive to the Tendon Force-Strain Relationship","Cop, Christopher P. (University of Twente); Jakubowski, Kristen L. (Emory University); Schouten, A.C. (TU Delft Biomechanical Engineering); Koopman, Bart (University of Twente); Perreault, Eric J. (Northwestern University); Sartori, Massimo (University of Twente)","","2024","Objective: Accurate estimation of stiffness across anatomical levels (i.e., joint, muscle, and tendon) in vivo has long been a challenge in biomechanics. Recent advances in electromyography (EMG)-driven musculoskeletal modeling have allowed the non-invasive estimation of stiffness during dynamic joint rotations. Nevertheless, validation has been limited to the joint level due to a lack of simultaneous in vivo experimental measurements of muscle and tendon stiffness. Methods: With a focus on the triceps surae, we employed a novel perturbation-based experimental technique informed by dynamometry and ultrasonography to derive reference stiffness at the joint, muscle, and tendon levels simultaneously. Here, we propose a new EMG-driven model-based approach that does not require external joint perturbation, nor ultrasonography, to estimate multi-level stiffness. We present a novel set of closed-form equations that enables the person-specific tuning of musculoskeletal parameters dictating biological stiffness, including passive force-length relationships in modeled muscles and tendons. Results: Calibrated EMG-driven musculoskeletal models estimated the reference data with average normalized root-mean-square error ≈ 20%. Moreover, only when calibrated tendons were approximately four times more compliant than typically modeled, our approach could estimate multi-level reference stiffness. Conclusion: EMG-driven musculoskeletal models can be calibrated on a larger set of reference data to provide more realistic values for the biomechanical variables across multiple anatomical levels. Moreover, the tendon models that are typically used in musculoskeletal modeling are too stiff. Significance: Calibrated musculoskeletal models informed by experimental measurements give access to an augmented range of biomechanical variables that might not be easily measured with sensors alone.","Biomechanics; Electromyography; Impedance; Joint stiffness; Mathematical models; muscle stiffness; Muscles; musculoskeletal modeling; Perturbation methods; tendon stiffness; Tendons","en","journal article","","","","","","","","","","Biomechanical Engineering","","","",""
"uuid:9f4ba4a1-8413-4622-b86b-c03eef1fdbdf","http://resolver.tudelft.nl/uuid:9f4ba4a1-8413-4622-b86b-c03eef1fdbdf","Faecal contamination on lettuce irrigated with different water sources in Maputo, Mozambique","Niquice, Celma (TU Delft Sanitary Engineering; Eduardo Mondlane University); Marques Arsenio, A. (TU Delft Sanitary Engineering); Medema, G.J. (TU Delft Sanitary Engineering); van Lier, J.B. (TU Delft Sanitary Engineering)","","2024","Faecal contamination across the lettuce value chain was assessed in Maputo, Mozambique. Escherichia coli was used as an indicator of faecal contamination, with concentrations ranging from 3.4 to 5.7 log units/100 ml in groundwater, river water and partially treated wastewater. Municipal tap water used to wash lettuce heads in the markets had lower than 1 log unit/100 ml. Irrespective of the source of irrigation water, the lettuce heads were contaminated throughout the value chain, with concentrations ranging between 6.5 and 7.8 log units/100 g. Interventions and awareness raising should be applied at every stage of the value chain.","Escherichia coli; irrigated urban agriculture; irrigation water sources; lettuce; Maputo; wastewater","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:835a8662-ebd2-4456-b9de-02ec74bb382f","http://resolver.tudelft.nl/uuid:835a8662-ebd2-4456-b9de-02ec74bb382f","Polydispersity effect on dry and immersed granular collapses: an experimental study","Polanía, Oscar (Universidad de los Andes; Université de Montpellier); Estrada, Nicolas (Universidad de los Andes); Azéma, Emilien (Institut Universitaire de France; Université de Montpellier); Renouf, Mathieu (Université de Montpellier); Cabrera, M.A. (TU Delft Geo-engineering)","","2024","The column collapse experiment is a simplified version of natural and industrial granular flows. In this set-up, a column built with grains collapses and spreads over a horizontal plane. Granular flows are often studied with a monodisperse distribution; however, this is not the case in natural granular flows where a variety of grain sizes, known as polydispersity, is a common feature. In this work, we study the effect of polydispersity, and of the inherent changes that polydispersity causes in the initial packing fraction, in dry and immersed columns. We show that dry columns are not significantly affected by polydispersity, reaching similar distances at similar times. In contrast, immersed columns are strongly affected by the polydispersity and packing fraction, and the collapse sequence is linked to changes of the basal pore fluid pressure P. At the collapse initiation, negative changes of P beneath the column produce a temporary increase of the column strength. The negative change of P lasts longer in polydisperse columns than in monodisperse columns, delaying the collapse sequence. Conversely, during the column spreading, positive changes of P lead to a decrease of the shear strength. For polydisperse collapses, the excess of P lasts longer, allowing the material to reach farther distances, compared with the collapses of monodisperse materials. Finally, we show that a mobility model that scales the final runout with the collapse kinetic energy remains true for different polydispersity levels in a three-dimensional configuration, capturing the scaling between the micro to macro controlling features.","avalanches; gravity currents; particle/fluid flow","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-21","","","Geo-engineering","","",""
"uuid:f09b9573-d963-4e11-a1d8-111eaebf3816","http://resolver.tudelft.nl/uuid:f09b9573-d963-4e11-a1d8-111eaebf3816","The Joint Optimization of a Wind Farm Layout and Wake Steering: A case study of IJmuiden Ver on the co-design of the wind farm layout and yaw control","de Jong, Robin (TU Delft Mechanical, Maritime and Materials Engineering)","van Wingerden, J.W. (mentor); Bos, René (mentor); Delft University of Technology (degree granting institution)","2023","Maximizing the extraction of energy from wind farms with ever higher densities is becoming increasingly more important in order to achieve climate targets and simultaneously preserve nature. Improving the yield of a wind farm can be achieved by optimizing the layout, applying control, especially wake steering through yaw control has shown great results, or even combining the optimization of the layout and control into one joint optimization. In this thesis, a case study is performed on the Dutch wind farm ’IJmuiden Ver’ to investigate the real-world applicability of joint optimization. The employed method uses the genetic algorithm, capable of handling the discontinuous domain, and an improved version of the geometric yaw relationship, making coupled or nested optimization redundant. In the IJmuiden Ver case, the levelized cost of electricity (LCOE) of a joint optimized layout compared to a sequential optimized layout is around 0.3% better, even remaining around 0.2% to 0.3% better when shrinking the domain to give nature more space. This shows that joint optimization is applicable in practice and has the potential to increase the yield of a wind farm substantially without significantly increasing the computational intensity of the wind farm layout optimization problem (WFLOP).","joint optimization; co-design; WFLOP; yaw control; geometric yaw; wind farm layout optimization; wake steering","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:8774897d-8f20-4e32-8fd2-a881bb626aaa","http://resolver.tudelft.nl/uuid:8774897d-8f20-4e32-8fd2-a881bb626aaa","The Impact of Technology Targets on the Design of a Climate Neutral European Energy System","van der Weerd, Giel (TU Delft Electrical Engineering, Mathematics and Computer Science)","Pfenninger, Stefan (mentor); Sanvito, F.D. (graduation committee); Delft University of Technology (degree granting institution)","2023","The European energy system faces one of its greatest challenges: transitioning from a system dominated by fossil-based energy sources to a completely climate neutral system in 2050. Energy system models provide useful tools that can help to navigate this complex task of designing a future energy system by modelling future systems and assessing the impact of future design choices.
Current literature adopts either a step-wise optimisation towards a final configuration of an energy system or deploys a modelling to generate alternatives (MGA) approach to generate a diverse set of system configurations. While the first approach provides temporal insights, it may biased and miss less trivial solutions, the second approach offers robustness but lacks insights into timing of technol- ogy deployments and neglects existing infrastructure. This highlights a gap in combining the strengths of both approaches to understand the dynamic between short-term decisions and long-term flexibility, while being robust under changing conditions.
The purpose of this study is to develop a method that combines the strengths of both modelling approaches. A method is developed and applied to two case studies to uncover how policy targets influence the maneuvering space towards a climate neutral European energy system. Many European nation states have set ambitious targets to increase renewable generation capacity while also phasing out fossil-based power generation. It is important to analyse impact of such targets on the rest of the energy system in the short- and the long-term. Aggressive phase-out or growth of deployed infrastructure might work in the short term but could restrict flexibility of options further into the future.
This study uses spatially explicit practically optimal results (SPORES) for 2030 and 2050 provided by the sector-coupled Euro-calliope model, which is an adaptation of the MGA approach. Energy system characteristics were found by analysis of the distributions of primary energy sources and power sector technology deployments. Trade-offs were uncovered by computing Pearson correlation of technology deployments on national and European scale. A k-means clustering algorithm was applied to condense the set of hundreds of SPORES to manageable amount of scenarios that is more accessible for poli- cymakers. The scenarios reveal trends and trade-offs between the two different time-frames. Finally, two case-studies were presented that use a filtering of the SPORES to reveal the impact of the 2030 PV capacity target in Germany and the 2030 offshore wind capacity target in the Netherlands on the maneuvering space of their respective future energy systems. Key finding of this study include:
• Phase-out of fossil-based energy sources by 2050 is enabled by a doubling of renewable elec- tricity generation by 2030 and a more than ten-fold increase of renewable electricity generation in 2050.
• Solar (PV) and wind turbines are must-have technologies by 2050, however trade-offs exist in the the proportional balance between them, and the timing and location of deployment.
• Early phase-out of coal-fired power generation can reduce flexibility in the system as it is often accompanied by high deployment of gas turbines and PV that could create lock-in risk.
• Germany’s ambitions to deploy 215 GW of PV by 2030 requires increased coal-fired generation capacity to remain in the cost-efficient design space of 2030. Thus the PV target introduces lock-in risk of coal-fired power generation, which requires a complete phase out by 2050.
• The Dutch offshore wind target of 21 GW by 2030 introduces a potential conflict between deploy- ment of offshore wind and growth of PV and onshore wind that is required for 2050.
These findings contribute to research by offering a methodology that improves understanding of the dynamics within the European energy transition. This study has, for the first time, placed MGA solutions in the context of the multi-decade transition. By analysing the change between the current system, the design space spanned by the 2030 and 2050 SPORES, new insights about the time dependent trade- offs within the energy system and the limitations of the SPORES method have emerged.","Energy system modelling; policy decisions; European energy system; Decarbonisation","en","master thesis","","","","","","","","","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:0d52b076-827f-4f6e-810e-c001b3d5d336","http://resolver.tudelft.nl/uuid:0d52b076-827f-4f6e-810e-c001b3d5d336","Computational modeling of KRAS mutant resistance mechanisms to targeted therapy","van der Ent, Huub (TU Delft Electrical Engineering, Mathematics and Computer Science)","Wessels, L.F.A. (mentor); Thijssen, Bram (mentor); Delft University of Technology (degree granting institution)","2023","KRAS mutations are very common in several different types of cancer. A promising targeted combination therapy using a MEK and HER inhibitor was proposed based on in vitro finding. The clinical results of this combination were found to be lacking due to emergent treatement resistance. Here we investigate what mechanism is causing this emergent resistance in KRAS mutant cancers. We propose a novel ODE model of the MAPK pathway that can be used to infer kinetic parameter estimates from a population of KRAS mutant cells under drug perturbation. Parameter estimates inferred from FRET biosensor data correctly predict protein activity in an external CyTOF validation dataset. However, the parameter estimates did not recapitulate the known gain-of-function in RAS activity that we would expect. From this we conclude that more experimental observation are required to elucidate the inner working of the resistance mechanism of KRAS mutant cancer to the proposed combination therapy.","","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:99d7d7ed-1ece-48b3-bf90-5cbd95c5d481","http://resolver.tudelft.nl/uuid:99d7d7ed-1ece-48b3-bf90-5cbd95c5d481","Mechanical characterization of thrombi by studying shear and friction: An in vitro study towards a better comprehension of thrombus biomechanics","van Kuijk, Sanne (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Biomechanical Engineering)","Gijsen, F.J.H. (mentor); Fereidoonnezhad, B.F. (mentor); Delft University of Technology (degree granting institution)","2023","Stroke, caused by large vessel occlusions, is the second leading cause of death worldwide. Large vessel occlusions are the result of thrombosis, the undesired coagulation of blood within the vasculature. Due to this coagulation, a vessel can get blocked, prohibiting blood flow to areas distal from the occlusion, with all the serious consequences that may ensue. Since 2015, mechanical thrombectomy procedures have been widely accepted as a successful treatment technique to remove thrombi from the vasculature. However, complete reperfusion is only reached in 50% of acute ischemic stroke cases.
To successfully remove a thrombus from the vasculature, it is necessary to apply a specific retrieval force. This force must exceed the opposing forces, including the impaction force generated by the blood pressure gradient across the thrombus and the interaction forces between the thrombus and the vessel wall. Multiple studies have focused on tensile and compressive properties of thrombi. However, little is known about shear loading of the thrombus and about the interaction properties of the thrombus-vessel wall interface. Therefore, the aim of this study is to gain a better comprehension of thrombus biomechanics by studying the shear behavior of thrombi and the interaction of the thrombus-vessel wall interface in vitro.
In order to perform these in vitro studies, two custom-made test setups have been designed and developed. The friction test setup contains a plate of which the angle can be inclined slowly. By placing a thrombus-vessel wall sample on top of this plate, it is aimed to determine the static and kinetic coefficient of friction of the thrombus-vessel wall interface. Furthermore, it is aimed to determine the effect of time on this interaction. The thrombus-vessel wall interface was created by obtaining a piece of vein and blood from pigs. To study the shear behavior of thrombi a shear test setup has been developed. Two thrombi types have been utilized for this study, red blood cell- and fibrin-rich. Within the shear test setup it is possible to perform shear experiments under different normal loading conditions. A comprehensive analysis of the data acquired from experiments performed with both test setups has been conducted. Furthermore, a computational model has been developed to fit towards the experimental data obtained from the shear experiments.
The friction experiments suggest that time positively influences the bonds formed between a thrombus and the vessel wall as the coefficients of friction increase with an increased waiting time. Furthermore, a strong positive correlation was found between the static and kinetic coefficient of friction. This result was also found when doing an extensive analysis of the data obtained from the shear experiments. Additionally, the shear experiment showed that the thrombus composition influences its mechanical properties. Higher shear moduli and kinetic coefficients of friction were found for the fibrin samples, compared to the red blood cell samples.
The results obtained from the friction and shear experiments provide valuable insights into thrombus biomechanics. By extending the performed studies a better comprehension on thrombus mechanics and the thrombus-vessel wall interaction can be achieved.","","en","master thesis","","","","","","","","","","","","Biomedical Engineering","",""
"uuid:3097e7ce-73aa-4312-ad5c-eb105cc97091","http://resolver.tudelft.nl/uuid:3097e7ce-73aa-4312-ad5c-eb105cc97091","Quasiparticle Dynamics in Disordered Superconductors: Modeling the Single Photon Response","Rugers, Thomas (TU Delft Applied Sciences)","Baselmans, J.J.A. (mentor); de Rooij, S.A.H. (graduation committee); Delft University of Technology (degree granting institution)","2023","Magnetic Kinetic Inductance Detectors (MKIDs) are very good radiation detectors which are even capable of single photon detection in the near-infra red and higher frequency range. MKIDs are currently used to detect exoplanets and the goal is to also retrieve information of the atmosphere of exoplanets.
However, MKIDs don’t have the photon absorption efficiency and resolving power to do this yet.
In this thesis we look at the single photon pulses of a new superconducting material, beta phased tantalum (β-Ta), since this material shows promising properties for MKIDs. The single photon pulse shapes of this material are not yet fully understood. Therefore we will create models for the quasiparticle dynamics in β-ta to try and further our understanding of the single photon pulses in this material.
From the Rothwarf-Taylor equations we derive multiple models. These are then tested on the data. We first try the double exponential model which does not work. Then we look at the 1/t model and this model does seem to work better. We propose a different response time of the system. Fitting a new response time we get a very good fit to the single photon pulses. The main hypothesis is that there is an extra relaxation time for the quasiparticles as they need to distribute themselves throughout the superconductor. We see that the fitted response time is wavelength dependent which would support the hypothesis.
We conclude that the 1/t model with an adjusted response time explains the single photon pule shapes the best.","Superconductivity; MKIDs; Single Photon Detection","en","bachelor thesis","","","","","","","","","","","","Applied Physics","",""
"uuid:2eabfd64-0be9-401b-8a23-9c4d01833f34","http://resolver.tudelft.nl/uuid:2eabfd64-0be9-401b-8a23-9c4d01833f34","Aerodynamic Interaction Effects Between a Propeller Slipstream and Flap Boundary Layer: A numerical study","Plijter, Jurrien (TU Delft Aerospace Engineering)","Sinnige, T. (mentor); Duivenvoorden, R.R. (mentor); Delft University of Technology (degree granting institution)","2023","This thesis investigates the aerodynamics of a propeller-wing-flap system, spurred by the growing interest in propeller-driven aircraft and the potential introduction of distributed electric propulsion. The research focuses on the complex flowfield involving the interaction of the propeller slipstream with the main wing and flap at high-lift conditions. Using unsteady RANS simulations at a chord based Reynolds number of 2 million, the study explores the impact of a propeller slipstream on flap time-dependent boundary layer variations. The computational results are validated against experimental data, showing good agreement. The analysis reveals intricate details of the flow field, including propeller slipstream shifts and complex vortex systems contributing to flap stall mechanics. The study highlights the influence of these phenomena on the spanwise lift distribution and flap flow separation areas. The findings contribute valuable insights into the understanding of propeller-wing-flap interactions, yet emphasizing the need for further research to confirm and expand upon the current discoveries.","CFD; high-lift device; Propeller Aerodynamics; URANS; ANSYS Fluent","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:5ad573ff-2396-4568-9012-427ad2a05cb1","http://resolver.tudelft.nl/uuid:5ad573ff-2396-4568-9012-427ad2a05cb1","The effects of surface cooling on the stability of a flat-plate boundary layer in subsonic flow","Goorden, Kristie (TU Delft Aerospace Engineering)","Kotsonis, M. (mentor); Michelis, Theodorus (mentor); Delft University of Technology (degree granting institution)","2023","The transition behaviour of a boundary layer with zero pressure gradient in a low-subsonic freestream is examined for a set of wall temperatures below the freestream temperature. Solutions of the boundary layer provided by both an incompressible and a compressible numerical flow solver are compared to wind tunnel measurements on a uniformly cooled section of a flat plate. The compressible solver features a temperature dependence of the fluid properties, which proves to be crucial for modeling the stability of a thermal boundary layer. Thermal images of the surface show that the spanwise-averaged transition front moves downstream with decreasing wall-to-freestream temperature ratio. At the streamwise station where no frictional heating due to turbulent structures is observed, T-S waves are detected in the measured velocity fluctuation profiles. The experimental data show good correspondence with the numerical linear stability predictions here. Further downstream, where streaks of transition occur, T-S waves can no longer be distinguished, and it is likely that non-linear effects have overtaken the boundary layer flow here. The absolute amplitude and the amplitude growth rate of the velocity perturbations both decrease with the wall temperature in the region where T-S waves are seen, and even more in the non-linear region. It is concluded that uniform surface-cooling stabilizes the boundary layer on a flat plate in an incompressible freestream, but a variable-fluid property solver is required to model the stability characteristics.","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:980ade3a-01be-4bff-8ee6-0d5c56470afe","http://resolver.tudelft.nl/uuid:980ade3a-01be-4bff-8ee6-0d5c56470afe","The Possibilities of Intermodal Transport to reduce Carbon Emissions in Logistics by Heineken","Senden, Tom (TU Delft Technology, Policy and Management)","Verbraeck, A. (mentor); Ludema, M.W. (graduation committee); Delft University of Technology (degree granting institution)","2023","The global commitment to combating climate change has led to initiatives like the Paris Agreement and the European Commission's 2030 climate target plan. Heineken, aligning with this, has set its own sustainability goals for 2030, aiming for net-zero emissions in its production line and a carbon-neutral value chain by 2040. To address emissions from logistics, Heineken introduced the Net-Zero Logistics program, with a focus on reporting emissions and implementing carbon reduction measures, particularly through increased use of intermodal transport.
Intermodal transport involves using various modes such as roads, railways, and waterways during transportation. Studies suggest that intermodal transport can aid in carbon reduction, aligning with Heineken's sustainability goals. The report aims to assess the impact of intermodal transport on Heineken's emissions, costs, and lead time compared to the current transport mode.
The study's primary objective is to identify opportunities for reducing transport emissions through intermodal transport, considering costs and lead time. A model and methodology were developed for the comparison between road and intermodal transport, utilizing available data.
Emission calculations follow a globally agreed framework, using emission factors per country, modality, and payload. Three methods are outlined based on the availability of intermodal transport data. The first relies on existing intermodal transport data, while the second uses locations of intermodal hubs when specific data is unavailable. The third method employs open-source data to identify intermodal hubs and is applied in regions like Africa.
Costs are determined through two methods: an internal intermodal pre-tender for Europe and average historical transport rates per kilometer for the U.S. and Africa. Lead time is calculated using intermodal databases when available or average transport speeds multiplied by distance with added dwell time.
Experiments were conducted on Heineken's existing transport routes with variations in region, lane distance, and transshipment hub distance. Findings from 34 experiments suggest that intermodal transport can reduce emissions and costs on distances exceeding 600 km. Additionally, for shorter distances, savings are possible if the first and last mile distance is below 30% of the total intermodal distance.
The study identifies that longer lanes show more significant reduction potential, especially in the U.S. where substantial opportunities remain untapped. Intermodal costs in the USA and Ethiopia should be verified with carriers for accuracy. The report recommends Heineken focus on longer lanes and explore integrated tools for real-time transport data analysis.
In conclusion, intermodal transport offers Heineken the potential to achieve its sustainability goals, with the report providing valuable insights into emissions, costs, and lead time comparisons. Future research could expand the analysis to more routes globally or within local operating companies, refining input values in collaboration with carriers.","Intermodal; logistics; transport; Emissions; Heineken","en","master thesis","","","","","","","","","","","","Engineering and Policy Analysis","",""
"uuid:79406c06-ab43-4cba-9136-cb8243e891ed","http://resolver.tudelft.nl/uuid:79406c06-ab43-4cba-9136-cb8243e891ed","S.C.A.L.E.: Scheduler for Carbon-Aware Load Execution in OpenShift at ING","Den Toonder, Jurriaan (TU Delft Electrical Engineering, Mathematics and Computer Science)","Durieux, T. (mentor); van Deursen, A. (graduation committee); Migut, M.A. (graduation committee); Braakman, P.G.P. (graduation committee); Delft University of Technology (degree granting institution)","2023","The global climate change crisis and the associated phenomenon of global warming have taken center stage in recent years. Greenhouse gas emissions due to electricity generation are a contributor to this problem. Internet Services running in data centers consume enormous amounts of energy and should be optimized to reduce their greenhouse gas emissions.
This thesis explores the possibility of intelligently scheduling resource-intensive batch data-processing jobs to green energy generation hours in the day. Green hours are hours within the day during which the amount of greenhouse gasses emitted per kilowatt-hour (kWh) is lower compared to other hours of the day. There is a variance in the amount of emissions due to the variability of renewable energy generation and grid demand.
The system ""S.C.A.L.E. (Scheduler for Carbon-Aware Load Execution)"" is proposed. It schedules compute jobs to periods of low-carbon-intense energy generation based on predictions of renewable energy generation and grid demand. The system was evaluated against a simulated data processing pipeline at ING; this pipeline is one of the larger consumers of the ING private cloud. The scheduler aims to reduce greenhouse gas emissions by intelligently predicting task running times and green hours for the next day and optimizing the times at which tasks are processed throughout the day.
Several main conclusions are drawn based on this research:
1. The accuracy of task load predictions regarding running times is crucial for effective scheduling. The research concludes that, with sufficient historical data, the scheduler can predict task running times with an acceptable margin of error (5-10%).
2. The research explores the scheduler's ability to predict periods of low carbon intensity and the resulting reduction in carbon emissions by implementing it. The research affirms the scheduler's accuracy in determining low-carbon-intensive energy generation periods and estimates a potential 20% reduction in greenhouse gas emissions.
3. The potential overhead introduced by implementing a carbon-aware scheduler is addressed. The research identifies that while the scheduling algorithm itself is lightweight, the concurrent processing of tasks introduces overhead. The tipping point, where the overhead outweighs the benefits, varies for each system and should be experimentally determined.
The thesis concludes by emphasizing the significance of implementing a carbon-aware scheduler to reduce the environmental impact of data centers. The proposed scheduler is a promising contribution to sustainable computing practices. Further, the research suggests the need for continued work and adoption of the scheduler into production environments, especially within the context of the ING data processing pipeline.","Climate change; Scheduling; OpenShift; Greenhouse gas; data center","en","master thesis","","","","","","https://github.com/Fastjur/S.C.A.L.E. Accompanying code","","","","","","Computer Science","",""
"uuid:9335f974-9adb-41f7-b6c2-3b87201913f6","http://resolver.tudelft.nl/uuid:9335f974-9adb-41f7-b6c2-3b87201913f6","Development of a Patient-Specific Carotid Artery Fluid-Structure-Interaction Model","Liu, Yanjing (TU Delft Mechanical, Maritime and Materials Engineering)","Akyildiz, A.C. (mentor); Tziotziou, A. (graduation committee); Delft University of Technology (degree granting institution)","2023","Background:
Ischemic stroke is a major cause of death worldwide. Atherosclerosis in the carotid arteries is an established predictor of these events. FSI shows its advantage in simulating the hemodynamic environments due to involving the multiphysics coupling of fluid dynamics and structural mechanics regulations. Therefore, the aim of this thesis was to establish and demonstrate a framework, starting with the segment data extracted from CTA images and leading to patient-specific FSI modeling. Thus the results can be used to gain insights into the relationship between plaque changes over time and biomechanical stresses induced by blood flow using FSI.
Method:
3D coordinates are firstly extracted from CTA scans of patients with calcified atherosclerotic plaques in their carotid arteries, sourced from the PARISK study. This data was then used to reconstruct 3D surfaces and volumes of the carotid bifurcation structure. Subsequently, the Backward Incremental method is employed to compute the initial stresses and establish the zero-pressure geometry of the vessel. Following this, FSI simulations were conducted on six carotid bifurcations to obtain preliminary results, providing an initial test of the pipeline's robustness. Morphological changes, including plaque burden, wall thickness, and calcium distance, are quantified to study plaque progression over time. The numerical simulation results provide insights into biomechanical stresses, including fluid and solid wall shear stress and von Mises stress. The simulation results are subjected to post-processing for further analysis. The results are mapped to a 2D configuration, with 1.5mm along the centerline and 45 degree per sector to study the local behavior.
Result:
The efficacy of the reconstruction and initial stress detection methods shows the robustness of the pipeline. The entire process is executed on six vessels, with a comprehensive examination of one case presented initially. This detailed analysis reveals metrics related to morphological changes, biomechanical stresses, and flow patterns. Subsequently, correlation and stress distribution analyses are conducted for all six vessels. Notably, negative correlations are discerned between stress and morphological changes, adding depth to the understanding of the relationship between biomechanics and morphological changes in these cases.","Atherosclerosis; Fluid-Structure-Interaction; Plaque Progression; Shear Stress; Structural Stress","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:3bf8900e-1d4b-4eb5-8087-842a32b374dd","http://resolver.tudelft.nl/uuid:3bf8900e-1d4b-4eb5-8087-842a32b374dd","Socio-economic feasibility study on the implementation of an Electric Road System between the port of Rotterdam and the port of Antwerp","Duijn, Kevin (TU Delft Civil Engineering & Geosciences; TU Delft Transport and Planning)","Annema, J.A. (mentor); van Binsbergen, A.J. (graduation committee); Tavasszy, Lorant (graduation committee); Saeednia, M. (graduation committee); Tuinenburg, Emilio (graduation committee); Koopman, Erik (graduation committee); Delft University of Technology (degree granting institution)","2023","In order to fulfill the climate commitments outlined in the 2015 Paris Climate Agreement, there is a pressing need to substantially reduce Greenhouse Gas (GHG) emissions worldwide. Among these GHG emissions, CO2 contributes for 75% of the total Greenhouse Gas emissions. The transport sector accounts for 22% of these CO2 emissions. Despite the only 2% of the overall vehicle fleet in Europe, trucks and buses contribute a substantial 28% to the annual CO2 emissions on roads. Decarbonizing the transportation sector can be approached with various solution, with electrification emerging as one viable solution. Electrification involves converting diesel trucks with internal combustion engines into battery trucks. Furthermore, extending this shift to heavy duty trucks can be achieved by implementing an Electric Road System (ERS), utilizing either inductive or conductive charging. Completing an European network for ERS would be optimal, considering the daily cross-border transportation undertaken by heavy-duty trucks. Given the challenges in constructing a full European network at once, it is recommended to start an ERS infrastructure between two major freight handling points to guarantee high initial utilization. Numerous studies and pilot projects have investigated ERS technologies, with the Overhead Catenary Line system currently standing out as the most mature technology. However, existing studies primarily focus on the technical aspects or cost-effectiveness of ERS technology, neglecting a crucial aspect—the Social Cost-Benefit Analysis (SCBA) that evaluates the socio-economic impact of implementing an Overhead Catenary Line system. Moreover, these studies mostly looked into the implementation of a larger ERS network. Consequently, the main research question is formulated: What is the socio-economic feasibility of the implementation of an Electric Road System (ERS), the overhead catenary line system, between two freight handling points?
The shift towards electrification has already begun, with the introduction of battery trucks alongside diesel trucks. Hence, a transitional phase involving a mix of diesel and battery trucks is anticipated in the coming years (the zero alternative). The study has focused on testing one policy measure, namely the implementation of an ERS infrastructure between the ports of Rotterdam and Antwerp. The implementation of an ERS network, extend the truck fleet (consisting of diesel trucks and battery trucks), with a new type: the catenary trucks. This is the so called policy scenario (anticipated completion by 2030), which has been compared with the zero alternative. Three distinct route alternatives between the ports were assessed through SCBA, revealing that implementing an ERS infrastructure proves welfare enhancing for all three route alternatives, thus demonstrating the socio-economic feasibility of the policy measure. Furthermore, among the route alternatives (the Western route, the Middle route and the Eastern route), the Eastern route presents the most favorable Net Present Value outcomes for ERS infrastructure. However, conducting further studies encompassing research variables and non-monetized factors arising from ERS infrastructure implementation is necessary. This comprehensive analysis is crucial for informed decision making regarding the successful implementation of an Electric Road System.
The thesis starts with an evaluation of literature to determine what options for sustainable and circular development business parks can implement. A variety of collective or individual initiatives aimed at either streams and production processes, or site arrangement, park organization and architecture/construction were found.
Next, case studies were performed to evaluate current policies and strategies on sustainable and circular development of business parks by the national, provincial and municipal governments. And to investigate the current practices, initiatives and developments at sustainable and circular business parks in Zuid-Holland. This resulted in a detailed overview of policies and strategies, and in depth documentation of four business parks using ten variables: (1) Initiation, vision and ambition; (2) Organization and actors’ roles; (3) Sustainable and circular initiatives at the park; (4) Physical location specific and business specific features; (5) Social location specific and business specific features; (6) Regional and local characteristics; (7); Regional spatial-economic strategies and environment policy; (8) Policy instruments; (9) Economic context; and (10) External context.
Lastly, based on a cross case analysis, eight key lessons were formulated for future development of sustainable and circular business parks.
The study identified three main perspectives of construction project managers: Cost and Sustainability, People and Sustainability, Cost and Quality. The study found that in current practice there is a general preference for safety over sustainability, while there are different perspectives on the sustainability compatibility with project objectives. The study highlights the need for continuous innovation and adaptation in incorporating sustainability while recognizing the diversity of management approaches and the multifaceted nature of construction projects.
While providing practical insights for industry practitioners, the study also recognizes limitations due to data subjectivity, regional differences, and changing external conditions. It is recommended that future research be conducted to compare sustainability integration in different countries and to explore the impact of cultural, economic, regulatory, and environmental factors on sustainable construction practices.","Sustainability; Construction project; Q method; Project management","en","master thesis","","","","","","","","","","","","Civil Engineering | Construction Management and Engineering","",""
"uuid:93f2206b-19b5-448f-8c4c-6c7b6b6b0055","http://resolver.tudelft.nl/uuid:93f2206b-19b5-448f-8c4c-6c7b6b6b0055","The role of International Cooperative Initiatives in achieving national climate targets in the Netherlands: The case of the chemical sector","Lehmkühler, Maren (TU Delft Technology, Policy and Management; Universiteit Leiden)","Ghorbani, Amineh (mentor); Blok, K. (graduation committee); Delft University of Technology (degree granting institution); Universiteit Leiden (degree granting institution)","2023","","international cooperative initiatives; corporate climate action; SBTi; Climate policy","en","master thesis","","","","","","","","","","","","Industrial Ecology","",""
"uuid:e0a6d2e3-6ec6-4edc-8e6a-5ae931d7dffb","http://resolver.tudelft.nl/uuid:e0a6d2e3-6ec6-4edc-8e6a-5ae931d7dffb","Computation-in-memory from application-specific to programmable designs based on memristor devices","Zahedi, M.Z. (TU Delft Computer Engineering)","Hamdioui, S. (promotor); Wong, J.S.S.M. (promotor); Delft University of Technology (degree granting institution)","2023","Computation-in-Memory (CIM) is a promising alternative to traditional computing systems where the storage is conceptually separated fromthe computing units. Instead, the CIM paradigm aims to perform the computation where the data resides, alleviating the memory bottleneck and ultimately leading to higher energy efficiency and performance. From the memory technology perspective, memristors, emerging non-volatile memory devices, demonstrate various beneficial characteristics. Although the concept of CIM, in combination with these emerging memory technologies, is in the infancy stage, it shows great potential as a future of computing systems. To further understand and quantify the potential of CIM, more development is required at each abstraction level. In this thesis, we first explore the main potentials for memristor-based computation-in-memory. Then, we study different applications from the CIM perspective to understand different behaviors and patterns of applications and use this knowledge to develop architectural solutions for CIM. Based on that, we study the realization of CIM as a generic and flexible platformat amicro-architecture level.","Computation-in-Memory; Memristor; Computer Architecture; Hardware Design; Instruction Set Architecture","en","doctoral thesis","","978-94-6366-789-0","","","","","","","","","Computer Engineering","","",""
"uuid:117ba361-fc12-4746-a108-3d554fbc5bab","http://resolver.tudelft.nl/uuid:117ba361-fc12-4746-a108-3d554fbc5bab","The Intelligent Built-Environment as Cyber-Physical System","Liu Cheng, Alexander (TU Delft Architectural Technology)","Eisemann, E. (promotor); Delft University of Technology (degree granting institution)","2023","Discussions of intelligence in the built-environment began in the late 1960s and early 1970s [1]–[7]. They belonged to a broader technical and technological discourse, engaged across a variety of domains and disciplines, to explore potential opportunities entailed by the Information Age. During this nascent period, and partly due to the novelty of the exploration as well as to the rudimentary state and forbidding costs of Information and Communication Technologies (ICTs), said discussions were principally theoretical and/or hypothetical in nature and impartial to defined fields of inquiry. Two main branches developed, one Technical—stemming from Information Sciences and Engineering fields—and another Architectural.
In the Technical branch, Ambient Intelligence (AmI) was coined in the late 90s to describe a cohesive vision of a future digital living room, a built-environment whose computing hardware and software technology imbued its dwelling space with serviceable intelligence to the benefit of its occupant(s) [8]. Also salient in this branch was Ambient Assisted Living—or Active and Assisted Living—(AAL), which framed its inquiry around the promotion of quality of life as well as the prolongation of independence with respect to Activities of Daily Living (ADLs) [9] among the elderly via technical assistance [10].
In the Architectural branch, Cedric Price’s pioneering Generator Project and corresponding programs by John and Julia Frazer [11] in the late 70s, explored notions of interaction between human and non-human agents in the built-environment. In Price’s project, architecture was conceived as a set of interchangeable sub-systems integrated into a unifying computer system, which enabled a reconfigurability sensitive to function. Price and the Frazers intended for the system to suggest its own reconfigurations, denoting non-human agency.
The promise of solutions yielded by both AmI/AAL and IA/AA is limited by the rigid and increasingly outdated assumptions in their approaches. It is not possible, as they are and as they are currently developing, to combine AmI/AAL and IA/AA to yield a unified and cohesive approach. This is because the sophistication of a system will depend on that of its mutually complementing subsystems; and two or more subsystems may not mutually complement, sustain, and/or support one another properly if their levels of development and sophistication do not correspond [12]. That is: at present, the architectural does not correspond to the technically predominant AmI/AAL, while the technical does not correspond to the architecturally predominant IA/AA. Consequently, a different design-approach is required in order to enable comprehensively and cohesively intelligent built-environments with corresponding levels of technical and architectural sophistication. What could such an approach look like?
In this thesis, an alternative approach that conceives of the intelligent built-environment as a Cyber-Physical System (CPS) is presented and demonstrated. Under this approach, ICTs and Architectural considerations in conjunction instantiate intelligence fundamentally—i.e., unlike existing AmI/AAL or IA/AA approaches, the present approach subsumes enabling technologies into the very core of the built-environment, where a solution does not exist as such without either of its informational and physical constituents deliberately conceived for each other (if not formally, at least conceptually and operationally with respect to instantiated services).
In this thesis, the general potential and promise of the presented approach is illustrated via its application to a constrained use-case—i.e., that of intelligent built-environments for elderly assistance and care (also informally referred to as smart homes or environments). Twelve proof-of-concept demonstrators (see Chapter 5), each showcasing an intelligent product and/or a service—or combinations and sets thereof—integrated into the built-environment and/or its ecosystem, are developed. Eight established parameters (see Section 3.2)—four pertaining to Indoor Environmental Quality (IEQ) and four Quality of Life (QoL)—define the purpose and inform the design of each demonstrator’s setup and development within four types of demo environments (see Chapter 4)—two Physical (Hyperbody and Robotic Building) and two Virtual (Digital Twin and Non-descript). Each demonstrator, while presented as a discrete proof-of-concept, builds on the same core System Architecture, and are intended to be viewed as a collection of systems and services expressed within a same hypothetical environment. That is to say, all come together to represent the intelligent built-environment as CPS.
All demonstrators are functionally and physically developed and involve human participation to test and to validate both the feasibility and success of the concept. Success is determined if the developed products and services indeed provide added value to a user and/or occupant of the space—i.e., if they promote and contribute to well-being by assisting, facilitating, or enhancing. Accordingly, the tangible nature of the process and results promote—albeit in a limited scope—the presented approach in very real terms, and—hopefully—situate it as an alternative to existing modes of imbuing intelligence in the built-environment.
The worldwide rapid development has led to an unprecedented urbanization process, which has brought numerous challenges and complexities to the rural-urban landscape in many different countries, including Linpan. I try to revisit the Linpan landscape in modern context with the holistic landscape concept, drawing on other rural heritage landscape preservation and reconstruction methods, keeping pace with the times and adapting to local conditions. At the Linpan scale, on the basis of a thorough understanding of the traditional characteristics of the forest, the functional division of the forest, and the wishes of the residents, Linpan will be transformed to varying degrees and in different directions, while at the same time ensuring that the internal and external circulation, which is a main characteristic of Linpan, will be preserved as much as possible. At the regional scale, the blue-green ecosystem network will be reconstructed to enhance ecological resilience, and the community will be categorized and spatially divided according to the situation and function of Linpan.
While preserving the natural ecosystems and revitalizing the traditional way of life in the woodland, I hope this could be a reference example for general rural transformation.","Rural landscape; Rural community regeneration; Water system; Linpan; Dujiangyan irrigation area; Holistic Approach; heritage landscape","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Landscape Architecture","","30.988056,103.646944"
"uuid:3f2b53e9-fc73-49e0-8b7d-f9e62bb2a419","http://resolver.tudelft.nl/uuid:3f2b53e9-fc73-49e0-8b7d-f9e62bb2a419","A Hybrid Reinforcement Learning and Tree Search Approach for Network Topology Control","Meppelink, Geert jan (TU Delft Electrical Engineering, Mathematics and Computer Science)","Cremer, Jochen (mentor); Rajaei, A. (mentor); Delft University of Technology (degree granting institution); Norwegian University of Science and Technology (NTNU) (degree granting institution)","2023","The growing demand for electricity, driven by widespread adoption of heat pumps, electric vehicles, and industrial electrification, strains power grids and introduces challenges for a reliable and secure supply amidst intermittent renewable energy integration. Network topology control offers flexibility, altering connections to redirect power flows and mitigate transmission line overloads. This thesis aims to investigate an ML and AI approach to overcome the computational complexity. The proposed approach merges a curriculum-trained machine learning agent with a Monte Carlo Tree Search (MCTS) to enhance power network action security. The MCTS guides the simulation of potential actions, considering future outcomes for improved long-term performance identification. A curriculum-based ML approach is used to pre-train an agent to propose grid actions. MCTS is then used to secure these actions, leveraging outcomes in the training algorithm for enhanced sample efficiency and reduced training times. The approach uses MCTS-verified, simulation-tested actions for immediate training feedback, eliminating the need to wait for scenario completion, enhancing sample efficiency. An electrically distance-guided search in the MCTS improves convergence by prioritising actions closer to overflows, often found to be most influential in reducing violations.","Machine Learning; Reinforcement Learning; Network Topology Control; Monte-Carlo Tree Search; Transmission Control; L2RPN","en","master thesis","","","","","","","","","","","","European Wind Energy Masters (EWEM) | Rotor Design Track","",""
"uuid:58042eb4-a229-402b-83bc-28cd48139825","http://resolver.tudelft.nl/uuid:58042eb4-a229-402b-83bc-28cd48139825","CFD simulations on the effect of the diameter of an interatrial shunt for the treatment of heart failure: A Master Thesis","Meindertsma, Guido (TU Delft Aerospace Engineering)","Gerritsma, M.I. (mentor); Delft University of Technology (degree granting institution)","2023","Interatrial shunting is a proposed technique to reduce elevated left heart and pulmonary pressures in heart failure patients. Clinical trials show promising results in relief of symptoms and improvements in quality of life, but little is still known about the working principles of interatrial shunting and important questions remain regarding the optimal diameter. The current research investigates the patient-specific optimal diameter of an interatrial shunt through computational fluid dynamics simulations. An idealized two-dimensional model of the left and right atria, four pulmonary veins, the two vena cavae and the two atrioventricular valves is used to study the intra- and interatrial flow fields in absence and presence of an interatrial shunt through steady-state and transient simulations. For the transient simulations, the inlets and outlets are coupled through a Windkessel including four reservoirs, representing the two ventricles and the pulmonary and systemic circulations. This coupling represents the closed-loop behavior of the circulatory system and ensures realistic inlet and outlet pressures throughout the cardiac cycle. Furthermore, wall movement is applied in the transient simulation to model the atrial deformation during the systolic and diastolic phases of the heart cycle. The introduction of an interatrial shunt significantly influences the atrial flow field and a shunt flow from the left atrium to the right atrium is observed in all the simulations throughout the cardiac cycle, increasing the ratio of pulmonary to systemic blood flow (Qp:Qs). This reduces pulmonary, left atrial and left ventricular pressures while slightly increasing systemic, right atrial and right ventricular pressures. The patient-specific optimal shunt diameter is studied by applying shunts with diameters ranging between 0 and 20 mm to three patients of varying left ventricular stiffness. From this, it is found that the pressure reductions of the smallest (< 6 mm) as well as the largest shunts (> 12 mm) are little sensitive to shunt diameter, whereas medium-sized shunts are the most sensitive to the diameter. It is concluded that the optimal shunt diameter is patient-specific and is defined as the smallest diameter that manages to reduce a patient’s peak pulmonary pressure to below 15 mmHg, as long as its Qp:Qs ratio does not exceed 1.5. Otherwise, the optimal shunt is the one with the largest diameter that does not exceed Qp:Qs = 1.5.","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:cb027554-81f8-43e2-8ed1-d6a1a4847d10","http://resolver.tudelft.nl/uuid:cb027554-81f8-43e2-8ed1-d6a1a4847d10","Clinical application of a statistical shape model for unilateral condylar hyperplasia","Klinkenberg, Edwin (TU Delft Mechanical, Maritime and Materials Engineering)","Huysmans, T. (mentor); Scheurs, R (mentor); Nolte, J (mentor); vd Ende, R (graduation committee); Delft University of Technology (degree granting institution); Leiden University Medical Center (degree granting institution); Erasmus MC (degree granting institution)","2023","Unilateral Condylar Hyperplasia (UCH) is a rare and complex asymmetric growth disorder affecting the mandible. The disease is characterized by growth resembling hyperactivity in one of the condyles. Treatment of UCH requires a personalised approach that aims to stop the progression and/or correct the deformity caused by the disease. The choice and timing of UCH treatment are determined by the expression, severity, and progression of the disease. One of the most recognized classifications, introduced by Obwegeser and Makek, delineates three primary UCH categories: hemimandibular elongation (HE), hemimandibular hyperplasia (HH), and a hybrid form combining the first two categories (HY). Despite efforts to effectively differentiate between UCH expressions, these classification systems heavily rely on qualitative assessments. Hence, there is a need for a tool to objectively determine the expression, severity, and progression of UCH. This study introduces a novel tool, MASQ, to quantify asymmetrical mandibular growth and aims to objectively distinguish between the three UCH categories described by Obwegeser and Makek.
In Chapter 3, asymmetry of the mandible was quantified in an unaffected population using the MASQ tool. These results were used to establish the amount of asymmetry present in an unaffected population. This enables the comparison of new mandibular samples to an unaffected population, which could facilitate the identification of asymmetrical growth caused by UCH in Chapter 5.
In Chapter 4, a machine learning model was developed for the MASQ tool to predict the expected mandibular shape of new samples. The model predicted unaffected mandibular shapes using the patients’ age and gender. Comparisons were made between the predicted model and the unaffected dataset (DFE-score), which could enable the identification and localisation of pathological growth caused by UCH.
In Chapter 5, the asymmetry and predicted model of the UCH samples were computed using the MASQ tool including the methodologies described in Chapter 2, 3, and 4. These UCH results were compared to the unaffected samples to help determine whether the growth deviations caused by UCH were significantly different. The UCH samples were classified in the three classifications described by Obwegeser and Makek. The results were used to identify characteristic growth patterns caused by the different expressions, which were used to confirm or refute the classification system.
The results revealed significant differences in asymmetry and DFE scores between UCH and unaffected samples. Additionally, the tool was able to objectively differentiate between the HE and HH class but could not fully confirm the classification of Obwegeser and Makek. This prompts the reconsideration of the existing classification system. Local results confirmed and revealed new characteristic deviations caused by the UCH expressions. These may be used in the future to establish a new UCH classification system using the MASQ tool. The current results not only deepen our understanding of mandibular variation but might also empower clinicians to make more informed decisions which could eventually result in a more effective, reliable, and patient-focused treatment.
The tool, developed using computational science, uses Python because of its capability to automate repetitive calculations. It integrates with the program D-Sheet Piling that is used for specific sheet pile calculations. The tool is designed to be used during the preliminary design phase, enabling quick assessment of potential reinforcement adjustments and facilitating insight into the preferred solution. It evaluates three main strategies for quay wall reinforcement: lowering active soil stress, increasing passive soil stress, and enhancing pile stability. The tool uniquely focuses on maximising the aggregated preference of involved stakeholders and is capable of evaluating failure mechanisms of sheet piles.
It is tested on three case studies, all located in the industrial harbour Loven in Tilburg. The results show that the tool effectively proposes which structural adjustments are applicable to create a sheet pile design that satisfies. The thesis concludes by drawing specific conclusions for each structural adjustment considered in the project. Moreover, it concludes that the development of a decision support tool has been successful. In particular, the tool enhances efficiency in sheet pile calculations, offers detailed insights into the environmental and financial impact of adjustments and enables the direct determination of the preferred configuration of structural adjustments. This eliminates the need to choose the preferred configuration from a number of designed variants, which is the current approach.
Additionally, the thesis recommends to conduct a follow-up research on the applicability of underwater anchors, which have shown significant structural potential. Furthermore, it recommends to conduct laboratory tests to potentially improve the cohesion and angle of internal friction of soil layers. If those soil parameters can be improved, no structural adjustment may be necessary to reinforce quay walls at all.","Design optimisation; Quay wall; Sheet pile wall; Preference Assessment; Decision support tool; reinforcement measures; Structural parametric design","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:64f8bf84-750f-4214-90ae-b7096057d707","http://resolver.tudelft.nl/uuid:64f8bf84-750f-4214-90ae-b7096057d707","Uncontrolled Degassing of Ships: An Agent-Based Approach","Dam, Friso (TU Delft Technology, Policy and Management)","van der Voort, H.G. (mentor); Warnier, Martijn (graduation committee); Wassenburg, S. I. (mentor); Merkx, P.P.A.B (graduation committee); Delft University of Technology (degree granting institution)","2023","The concept of deterrence, using fear of punishment to encourage compliant behavior, is widely discussed. However, deterrence often places an emphasis on the economic side of compliance while neglecting other possibly crucial factors, as is argued by the literature. Psychological factors, notably the personal norm and the social norm, often appear to play important roles in the decision to comply or not. The personal norm describes an individual’s attitude and moral stance toward specific behaviors, such as compliance. On the other hand, the social norm revolves around perceptions of others’
behavior and opinions within one’s social network. Hence, the influence of these factors is researched within different populations, and different environments, some enabling and some impeding compliance. A new framework to encompass all these elements is explored with Agent-Based Modeling and applied to a case study in collaboration with the ILT (Inspectie Leefomgeving en Transport). Findings included the lack of a social influence on compliance, whenever the personal norm was high and the necessity to be able to comply in order for deterrence to show an effect. For future research, suggestions are done to improve the framework and to explore additional aspects.","Agent-based Modeling; Compliance; Deterrence; Theory of Planned Behavior; Rational Choice Theory","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:1fad76b4-bcd3-4915-9a94-40e4ced35abd","http://resolver.tudelft.nl/uuid:1fad76b4-bcd3-4915-9a94-40e4ced35abd","The Effect of a Confining Cover Layer on Backward Erosion Piping Process: Investigation of the initial heave progression","Willemstein, Lotte (TU Delft Civil Engineering & Geosciences)","Hicks, M.A. (mentor); Brinkgreve, R.B.J. (graduation committee); Kok, M. (graduation committee); Wiggers, Albert (graduation committee); Sanders, Monique (graduation committee); Delft University of Technology (degree granting institution)","2023","The Netherlands is prone to flooding as more than a quarter of the country lies under sea level. To combat flooding and ensure that the country remains dry structures such are levees and dikes have been installed. However, older water retaining structures are more than ever failing the stringent safety standard assessments. These older conventional reinforcement measures, including berm constructions, are not only costly but require an expanse of ground to ensure performability.
Backward erosion piping is an internal erosion mechanism during which shallow pipes are formed in the direction opposite to the flow underneath water-retain structures as a result of the gradual removal of low cohesive material by the action of water. This mechanism is an important failure mechanism in both levees and dams where a cohesive layer covers a sand layer. Although failure resulting from backward erosion piping is not common, several levee failures in the United States, China and the Netherlands have been attributed to this mechanism.
There are mitigation measures known to stop the backward erosion mechanism. One such measure is the placement of a seepage wall, to create a physical barrier directly in the flow path trying to reach the lowest region of the hydraulic head. A review of the literature showed that current design rules only consider groundwater flow calculations when determining the likelihood of hydraulic heave, one of the failure modes within the backward erosion process. Hydraulic heave in the backward erosion piping context is closely linked to the quicksand condition, essentially stating that once the effective stress is zero, the sand particles become suspended, liquifying a solid layer. The absence of an assessment of the effective stresses during the design process in conjunction with hydraulic heave has contributed to the main research question addressed by this thesis; How does a restricted exit for groundwater flow affect hydraulic heave compared to Terzaghi’s free exit situation?.
inaccuracy.","Observer Performance; Object Detection; Bounding Box; Trust","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:f7ec9e1c-15db-4982-b2fa-4ba0f51a5b91","http://resolver.tudelft.nl/uuid:f7ec9e1c-15db-4982-b2fa-4ba0f51a5b91","Aerial Perching via Active Touch: Embodying Robust Tactile Grasping on Aerial Robots","Jadoenathmisier, Anish (TU Delft Aerospace Engineering)","Hamaza, S. (mentor); de Croon, G.C.H.E. (graduation committee); Pool, D.M. (graduation committee); Bredenbeck, A. (graduation committee); Delft University of Technology (degree granting institution)","2023","Aerial manipulators, characterized by their ability to actively engage with the environment, are gaining popularity for their versatility in performing diverse tasks.
This research focuses on augmenting the capabilities of aerial manipulators through the integration of tactile feedback, specifically employing a compliant bio-inspired three-fingered manipulator equipped with tactile capacitive sensors on each finger. The manipulator is affixed to a drone, enabling tactile-guided navigation for precise object localization, subsequent grasping, and perching. Additionally, a grasp evaluator assesses grasp quality, allowing the system to adapt by suggesting alternative grasp locations after an initial attempt is unsuccessful. A comparative analysis between the system’s performance using tactile feedback and open-loop perching/grasping in perching scenarios demonstrates that the grasp evaluator improves the perching success rate by 55%-point and increases the allowable object uncertainty by 0.14 [m]. These findings highlight the efficacy of this approach in advancing aerial manipulator capabilities.","","en","master thesis","","","","","","","","","","","","Aerospace Engineering | Control & Simulation","",""
"uuid:abc4d59b-ae5c-423e-b84f-f287bf148df6","http://resolver.tudelft.nl/uuid:abc4d59b-ae5c-423e-b84f-f287bf148df6","Synthetic Human Motion Video Generation Based on Biomechanical Model","Lyu, Bofan (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Biomechanical Engineering)","Seth, A. (mentor); van der Kruk, E. (graduation committee); Zhang, X. (graduation committee); van der Helm, F.C.T. (graduation committee); Delft University of Technology (degree granting institution)","2023","Biomechanics studies the underlying mechanisms between body movements and forces. Accurate motion data is crucial for the biomechanics. Currently, marker-based motion capture systems are often used by researchers to record motion data. Marker-based motion capture systems are not widely adopted due to its drawbacks in terms of financial and time costs, portability, etc. Video-based motion capture systems can record motions using videos collected by webcams, cameras, and smartphones as the input and then estimate human motions from those videos. A simpler setup makes video-based motion capture technology more accessible for widespread use. However, existing motion capture datasets commonly lack of biomechanically accurate annotation, resulting in a deficiency in the biomechanical accuracy of exsisting video-based motion capture methods. In the biomechanics community, there are a lot of validated and biomechanically accurate models and motion data; however, corresponding video data is lacking. We can construct human-like appearance based on these data and generate a synthetic human motion video dataset using 3D graphic software. In this thesis, we purposed a pipeline that can generate synthetic human motion videos. The pipeline takes subject-specific OpenSim model and motion as input and uses SMPL-X model to generate human-like appearance. We validated the synthetic data generated by our pipeline and demonstrated the biomechanical reliability of the pipeline. Using this pipeline, we created synthetic dataset ODAH with biomechanically accurate annotations for neural network training.","Motion capture; biomechanical model; OpenSim; synthetic video; SMPL-X model","en","master thesis","","","","","","","","2024-04-30","","","","Mechanical Engineering | BioMechanical Design","",""
"uuid:f75c3508-ae6b-4952-86ff-4aed5dbf08d7","http://resolver.tudelft.nl/uuid:f75c3508-ae6b-4952-86ff-4aed5dbf08d7","Decision-making on local flood risk measures in area development in unembanked areas","Nelen, Louis (TU Delft Civil Engineering & Geosciences)","van Bueren, Ellen (graduation committee); Esteban, T.A.O.E. (mentor); Kok, M. (graduation committee); Delft University of Technology (degree granting institution)","2023","Cities worldwide are facing increasing impacts from climate hazards such as heavy precipitation, heat stress, flooding, and drought, exacerbated by climate change. This study focuses on unembanked areas (NL: buitendijkse gebieden), vulnerable to flooding due to factors like sea-level rise, river peak discharges, and land subsidence. However, there are many plans for (re)development in Dutch unembanked areas for the coming years. To address these challenges and avoid passing on consequences of what we build now to future generations, effective adaptation measures are crucial. The study investigates the decision-making process for local flood risk measures in unembanked areas, examining appropriate evaluation methods and stakeholders' needs. Qualitative research methods, including expert interactions, a literature review, case studies, and interviews, were employed. Although there are not evaluation methods, the Dutch multi-level safety approach and resilience-based planning methods like adaptative pathway and adaptative tipping point were found applicable to guide the decision-making process in unembanked area development.
For evaluation methods, multi-criteria analysis (MCA) emerged as a suitable tool for decision-making in unembanked area development, considering social values and intangible criteria. Combining MCA with cost-effectiveness analysis (CEA) or a form of cost-benefit analysis (CBA) proved effective in balancing quantitative and qualitative criteria, facilitating inclusive decision-making. The research emphasizes the extensive involvement of various stakeholders and identifies barriers related to legal aspects, risk awareness, and communication. Stakeholders call for well-defined guidelines, legal regulations, and collaboration between private and public entities. The study recommends establishing principles for unembanked area development and translating them into MCA criteria, addressing both social values and local characteristics. Further research is suggested to address legal assurance for climate-adaptive construction, increase awareness, enhance flood risk assessment methods and communication, and strengthen collaboration between private and public stakeholders in flood risk management and spatial planning.","Unembanked areas; Flood risk management; Evaluation methods; Decision-making; Climate adaptation measures; Risk Governance","en","master thesis","","","","","","","","","","","","Civil Engineering | Construction Management and Engineering","",""
"uuid:7f762d85-25d4-450b-a4a6-fc467e549d3b","http://resolver.tudelft.nl/uuid:7f762d85-25d4-450b-a4a6-fc467e549d3b","Validating Reusability: Assessing the Cleanability of the Vela Vacuum Extractor: A Study to Enhance Sustainability and Accessibility of the Vacuum Extractor Before Final Material Production","van Leeuwen, Cato (TU Delft Mechanical, Maritime and Materials Engineering)","Dankelman, J. (mentor); Drexhage, Dieuwertje (mentor); Leeuw, Harry (mentor); Diehl, J.C. (mentor); Delft University of Technology (degree granting institution)","2023","INTRODUCTION: The importance of reusable medical devices is increasingly evident due to their sustainability and accessibility advantages in high- and low- & middle-income countries. In response, LAYCO Medical Devices is developing a reusable vacuum extractor, vela®, as an alternative to the commonly used disposable vacuum extractor. This study aims to validate vela®’s reusability, focusing on reprocessing and explicitly on cleaning. The design of vela® is nearing completion; however, the device has not been manufactured in the final material. Ultimately, the plan is to produce vela® through injection molding of polyphenylsulfone. However, given the current stage of vela®, both in terms of time and cost, it is not advantageous to apply this production method now. Therefore, the research is divided into two parts: material validation and design validation. The material validation involves examining the suitability of polyphenylsulfone, the proposed final material, and identifying a suitable prototype material for testing the cleanability of the vela® design. For the design validation, the vela® design is examined to determine its effectiveness in cleaning within both high- and low- & middle-income countries, as different reprocessing methods are used in these settings.
METHODS: Clinical simulation tests were performed in the material and design validations to assess contamination at predefined hard-to-clean locations after cleaning. The locations were first soiled with Browne washer-disinfector soil, then cleaned and tested with the adenosine triphosphate and protein tests, each with predetermined thresholds. For material validation, an object made of polyphenylsulfone was selected. Through 3D printing, the polyphenylsulfone object was replicated in five potential prototyping materials to facilitate a comprehensive comparison. These six test objects were subjected to clinical simulation tests. Then, the test objects underwent in-depth material analysis to understand the material better and make a more reasoned selection for the prototype material. For the design validation, the design of vela® is printed in the material obtained through the material validation. These vela®’s undergo clinical simulation tests in both high- and low- & middle-income country settings. Given the manual nature of the low- & middle-income country cleaning procedure, additional layman’s tests are conducted to minimize user bias.
RESULTS: For the clinical simulation tests of the material validation, the results obtained from the polyphenylsulfone test object remained below the predetermined threshold. For the prototype material, only the test objects made of polycarbonate and tough 2000 resin withstood the cleaning procedure, and the tests stayed below the predetermined threshold value. Subsequently, the material analysis revealed that polyphenylsulfone and tough 2000 resin have the
least surface irregularities and absorb the least water. Therefore, the vela® prototype was printed in tough 2000 resin. For the clinical simulation tests of the design validation, contamination was observed at specific locations of vela® in
both test settings. In the high-income country setting, test results above the threshold value are observed in the space between the diaphragm. The results are more varied in the low- & middle-income country setting; hence, layman’s
tests were added to minimize user bias and obtain a more concrete result. Ultimately, test results above the threshold value are observed in the space between the diaphragm and the connection between the tube and handle.
CONCLUSION: For the material validation, polyphenylsulfone is identified as a suitable material for the final vela®. Tough 2000 resin is deemed appropriate as a prototype material to validate cleaning. For the design validation, it is concluded that design improvements are needed for two specific locations on the vela® to improve cleaning. The connection requires a redesign to facilitate easy disassembly. The diaphragm with stem is composed of silicone and hard plastic, and it is advisable to employ two-component injection molding to produce this part. When incorporating these suggestions into the design, it can be concluded that vela® can be safely reused in both high- and low-&middle-income countries, contributing to the sustainability and accessibility of medical devices.","","en","master thesis","","","","","","","","2024-12-21","","","","Biomedical Engineering","",""
"uuid:bcd64fd0-c2c1-4fd5-a854-e24ccc2a9a39","http://resolver.tudelft.nl/uuid:bcd64fd0-c2c1-4fd5-a854-e24ccc2a9a39","Pick & Place of Waveguide Structures: Heterogeneous Integration","Fakkel, Stein (TU Delft Electrical Engineering, Mathematics and Computer Science)","Ishihara, R. (mentor); van der Maas, M.C. (mentor); French, P.J. (graduation committee); Delft University of Technology (degree granting institution)","2023","Classical computer have difficulties simulating specific complex problems, therefore other computation options are being explored. One of these options is the quantum computer, which is expected to excel in various industries. The challenge for the quantum computer is scaling it up to a high number of qubits. The diamond-based quantum computer is a suitable candidate for quantum computer, because it can be made scalable, with long coherence times, relatively high temperatures and low cross talk. Making such a scalable modular quantum computer using diamond qubits requires heterogeneous integration of optical components. Multiple integrations techniques for optical components exist, however in this thesis we are particularly interested in integrating a superconducting nanowire single photon detector (SNSPD) with pick & place onto the quantum chip to read out the photons emitted by diamond color-centers. The main goal of this thesis is to find out which integration scheme leads to the highest on-chip detection efficiency of a pick & place on waveguide integrated SNSPD.
In this work we designed a silicon nitride structure with low loss tapered support structures. Next different releasing methods are introduced to release the fabricated silicon nitride structure independent of the material stack and with a high yield. Lastly, we show how waveguide structures can be pick & placed on receptor chips that underwent surface treatment.","Pick-and-Place; Quantum computers; Heterogeneous integration; SNSPD","en","master thesis","","","","","","","","2025-12-21","","","","Electrical Engineering","",""
"uuid:ee817413-c529-4afd-bfce-84e6199d5b4c","http://resolver.tudelft.nl/uuid:ee817413-c529-4afd-bfce-84e6199d5b4c","A Configurable Digital Neuromorphic Hardware Generator for Heterogeneous Computing","LIN, Jinhuang (TU Delft Electrical Engineering, Mathematics and Computer Science)","Frenkel, C. (mentor); Makinwa, K.A.A. (graduation committee); van Leuken, T.G.R.M. (graduation committee); Delft University of Technology (degree granting institution)","2023","Recent trends in machine learning (ML) have placed a strong emphasis on power- and resource-efficient neural networks, as well as the development of neural networks on edge devices. Spiking neural net-works (SNNs), due to their event-based nature, are one of the most promising types of neural networks for low-power applications. To accelerate and ease the deployment of SNNs on edge devices, this thesis presents a configurable digital neuromorphic hardware generator for heterogeneous computing that is capable of generating resource-efficient SNN processing cores. The proposed hardware generator is de-veloped using SpinalHDL, a high-level hardware description language (HDL), which provides a high level of flexibility in hardware generation. Our generator supports the configuration on various parameters and is capable of generating a tree-structured multi-core architecture of heterogeneous cores. The generator is deployed in a sensor-fusion hand-gesture classification use case, for which the configurability of our hardware generator is a key enabler.","Neuromorphic hardware; Spiking Neural Network (SNN); Hardware Accelerator","en","master thesis","","","","","","","","2025-12-21","","","","Electrical Engineering","",""
"uuid:5012bc3d-cece-44ea-850a-1356df1fe5dc","http://resolver.tudelft.nl/uuid:5012bc3d-cece-44ea-850a-1356df1fe5dc","Magnetoencephalography to image the influence of different spinal cord stimulation paradigms on somatosensory evoked responses","Luijten, Janne (TU Delft Mechanical, Maritime and Materials Engineering; Erasmus MC)","de Vos, C.C. (mentor); Schouten, A.C. (mentor); Frankema, S.P.G. (mentor); van de Ruit, M.L. (graduation committee); Delft University of Technology (degree granting institution); Erasmus Universiteit Rotterdam (degree granting institution); Universiteit Leiden (degree granting institution)","2023","b>Introduction
Chronic pain is an increasing problem in terms of prevalence and disease-related costs. Due to its complexity, it is difficult to treat. Spinal cord stimulation (SCS) is a neurostimulation therapy with a relatively good success rate for patients with severe, intractable chronic pain. The mechanisms of action (MOAs) of SCS are considered to rely on spinal and supraspinal mechanisms. It has been suggested that newer SCS paradigms, such as burst SCS, may act through different MOAs than the traditional tonic SCS paradigm. Tonic and burst SCS are both postulated to act on the lateral pain pathway, which is associated with the location and character of a stimulus, whereas burst SCS is postulated to additionally act on the medial pain pathway, which is associated with the emotional/attentional processing of a stimulus. Somatosensory evoked responses (SERs) can be used to evaluate the processing of somatosensory stimuli and may aid in the unraveling of the MOAs of SCS.
Aim
The aim of this thesis is to assess how burst and tonic SCS affect the supraspinal SERs elicited by non-painful transcutaneous electrical stimulation of the tibial nerve as well as of the median nerve. The two distinct SERs are evaluated using magnetoencephalography (MEG).
Methods
26 chronic pain patients treated with SCS underwent MEG sessions after receiving tonic and burst SCS for one week. Four of these patients additionally underwent a MEG session before SCS treatment. During each session, approximately 200 non-painful electrical stimuli were applied to the median nerve as well as to the tibial nerve to elicit SERs. The SERs were compared in various cortical and subcortical regions of interest (ROIs). The following comparisons were made: 1) SERs in chronic pain patients before SCS implantation versus SERs in the same individuals during SCS, 2) SERs elicited by tibial nerve stimulation versus SERs elicited by median nerve stimulation, 3) SERs during tonic SCS versus SERs during burst SCS, and 4) the SERs in four case studies of two good and two poor responders to the tonic and/or burst SCS paradigms.
Results
22 patients were included for analysis. The number of patients varied among comparisons to facilitate within-patient comparisons. The results suggested an inhibitory effect of SCS on the SER elicited by tibial nerve stimulation, whereas the amplitude of the SER elicited by median nerve stimulation tended to increase during SCS. For both the SERs elicited by tibial nerve and by median nerve stimulation, the SER amplitudes were predominantly higher during burst SCS compared to tonic SCS. Differences in SER amplitude that were observed in the case studies did not correlate with pain relief.
Conclusion
The results suggested a spinal MOA of SCS on the SER, however, supraspinal MOAs likely play a role as well. The results did not suggest that burst SCS additionally acts on the emotional/attentional processing compared to tonic SCS. No evidence was found to support a correlation between the effect of SCS on the SER and the effect of SCS on the pain, underscoring the complexity of the relationship between somatosensory processing and pain perception in the context of SCS.
A statistical analysis was made on haul truck accidents from 1983 until 2022. The accidents that proved to be most relevant were included in the content of the training software. A training software was developed using Unreal Engine 5, where trucks could be driven using a Thrustmaster T150 Pro steering wheel and driving pedals. 18 participants from ages 19-65 underwent the training program and two tests of identical difficulty were taken before and after undergoing the training, in order to make a judgement on the progress of the participants by undergoing the training simulation. Participants were judged based on the number of crashes and traffic violations committed, attempts required to complete the test, as well as the time taken to finish the test. A score was calculated based on these factors providing an overall judgement of the participants’ level of skill.
Average skill of participants increased by undergoing the gamified training, and training showed particularly good progress for underperformers in the initial test. After completing the gamified training the average score of participants was notably higher and the standard deviation was notably lower. It was concluded that all participants were brought to a comparably high level after completing the training.
The proposed workflow involves an extensive literature review of current and near-future decarbonisation technologies to replace diesel equipment and to create a haulage network based on block model data using the software Xpac Quarry solutions and its Haulnet package. Diesel equipment is imported from the Quarry solutions database and used as a base case to compare BEV and trolley assist simulations. Hydrogen and HVO fuel consumption have been calculated manually to obtain NPVs and associated emissions. An investigation into required infrastructure and energy requirements has been done to accurately define costs and resulting total CO2eq emissions.
The results indicate that replacing diesel at Ipoh with any of the decarbonization methods will result in a negative NPV as the infrastructure requirements need extensive capital investment of which the payback period often exceeds the life of mine. The least expensive method to implement HVO fuels, followed by BEVs and green hydrogen. Furthermore, it has been found that using BEVs instead of diesel at Ipoh is more environmentally polluting because producing 1 kWh of electricity is more polluting than producing the same energy worth of diesel. Green hydrogen is the least polluting method with no greenhouse gas emissions associated with it, followed by alternative fuels. When investigating the technological feasibility of the three main decarbonization options, hydrogen is the furthest away of being technologically feasible as from now. No green hydrogen using water electrolysers has been produced at an industrial scale, and a lack of technical expertise and infrastructure is present regarding distribution, transportation, and storage. Currently, no hydrogen LHD equipment is commercially available currently, and the same applies to BEVs that could replace the current equipment used at Ipoh. To bridge this gap, alternative fuels are the best option, but the market is competitive, and supply is limited. This project has given a good overview of current possibilities and clearly shows today’s options for decarbonisation and where industries stand with respect to infrastructure and equipment.
A software solution integrated in Blender (Blender Foundation, The Netherlands), has been developed to generate semi-automatic preoperative plans. The software optimizes one to three closed wedge osteotomies, by minimizing the dissimilarity from a deformity shape after osteotomy, to a target shape. The deformity shape is the centreline of the deformed femur. The target shape in this study is the centreline of an intramedullary nail.
A cost function was created that makes use of the Hausdorff distance and the root mean squared error to quantify the dissimilarity between the deformity shape after osteotomy and the target shape. Clinical constraints to the model are femoral length and collum anteversion angle. Using a multi-objective genetic algorithm the cost function is minimized within the bounds of the set clinical constraints.
To validate the method of semi-automatic generation, 20 bone models of deformed femora have been created from retrospectively collected CT data. The proposed solution was used to generate preoperative plans, which were scored by two independent assessors. After the creation of an initial preoperative plan and a maximum of two revisions of the plan, 18 of 20 semi-automatically generated preoperative plans were eligible for surgery. Four cases of femoral deformity were randomly selected from the dataset and counterparts to the existing automatic preoperative plans were created manually. 30% to 575% more time was needed to design a preoperative plan manually compared to the semi-automatic generation. In all preoperative plans in the automatic group, the collum anteversion angle of the postoperative configuration was within the normal range of 8-15 degrees. In the manual group, one of four postoperative configurations had a collum anteversion angle within this normal.
The proposed method for semi-automatic preoperative plan generation is a novel, versatile approach with the ability to optimize multiple osteotomies to mimic a given target shape. The automatic planning tool is a promising aide to both technicians and clinicians for a fast preoperative planning withing the boundaries of clinical anatomical normal ranges.
In response, this thesis introduces an innovative deep learning model, PandID-Net, designed specifically for P&IDs. PandID-Net uniquely integrates symbol detection, line detection, and text recognition into a single model, diverging from previous methods that relied on separate models and rule-based techniques. It is the first method that uses deep learning for the line detection task in P&IDs. This all in one approach not only simplifies the processing pipeline but also enhances computational efficiency in detecting and pinpointing symbols, lines, and text, as well as their interrelationships.
The optimal configuration of PandID-Net is found by an ablation study where the performance of individual components is tested in isolation. This optimized configuration is then evaluated and benchmarked against a prior study by Paliwal et al. on the same dataset. PandID-Net achieves a performance in F1 scores of 92.89 and 94.48 for line detection and keypoint detection respectively
An example of a promising service involves the application of shared bicycles with hubs at all key locations in the service area and various hubs in the neighbourhood (back-to-many). Anticipating on the requests of residents and businesses. The service is connected to all municipalities in the area, with an emphasis on connecting at least one large town or city. If this collaboration is established, shared e-bikes are introduced, primarily focused on distances exceeding 3 kilometres. Finally, the system can be complemented with shared mopeds, limiting their use to a few hubs per municipality. This allows for effective control of usage and minimizes disturbances. Limiting the number of locations makes it possible to create physical parking facilities for mopeds, which contributes to mitigating inconvenience. However, every situation is unique, this thesis provides guidance on the approach to be considered for different scenarios.","Shared micromobility; Shared bicycles; Shared e-bikes; Shared mopeds; Suburban; MNL; Survey; Expert interviews; Stated preference experiment","en","master thesis","","","","","","","","","","","","Civil Engineering | Transport and Planning","",""
"uuid:0c674754-1e89-4857-a96e-f7508e2dda71","http://resolver.tudelft.nl/uuid:0c674754-1e89-4857-a96e-f7508e2dda71","The impact of hydropower development on silt and clay loads in the Mekong Delta","Cornielje, Floor (TU Delft Civil Engineering & Geosciences; TU Delft Water Management)","Blom, A. (mentor); Sloff, C.J. (graduation committee); Bogaard, T.A. (graduation committee); Delft University of Technology (degree granting institution)","2023","The hydropower development in the Mekong Basin affects the silt and clay concentrations in the river which has ecological as well as socio-economic effects on the Mekong Delta and its inhabitants. Therefore, the first objective of this research was to obtain a better understanding of the effect of hydropower development on the silt and clay load in the Mekong Delta. Subsequently, the objective was to determine possible sediment management strategies to mitigate the impacts on the silt and clay load in the Mekong Delta.
A conceptual model was developed and applied to analyse these impacts. By means of a sediment balance model with distributed sediment yield and individual trapping efficiencies of dams the annual sediment load has been determined.
This research has shown that the annual silt and clay load downstream has decreased from 140 Megaton ± 40 [Mt] before hydropower development to 26 ± 9 Mt in 2020. Including future hydropower dam projects, this could further decrease to 4-8 ± 3-5 Mt in 2040. Approximately 4% of this sediment load will deposit in the Mekong Delta and therefore it is predicted that the clay and silt deposition will be close to zero in the future.
By 2040, approximately 75% of the total trapped sediment load is trapped in mainstream dams even though they account for 16% of the total dams. The majority (50%) will get trapped in Chinese dams that account for 9% of the total number of dams. This means that almost all sediment coming from China is trapped and will not reach the Mekong Delta. Around 80-85% of the future sediment load that will reach the delta has its source in the 3S region.
This reduction has implications for the sustainability of ecosystems and the productivity of the Mekong Delta. Clay and silt are nutrient rich alluvial sediments that support the ecosystems in the floodplains and delta. These nutrients are crucial for the soil fertility vital for rice cultivation and for various biological processes for fish. Today, nearly 80% of the 20 million people living in the Mekong Delta depend on the river system for their livelihood. However, the rice cultivation is expected to decrease significantly and by 2040, the loss of fisheries could cost close to $23 billion.
Thus, the computed reduction displayed that sediment management strategies are inevitable to maintain the productivity of the Mekong Delta in the future. Therefore, two sediment management strategies were reviewed in this research: cancelling planned dams and reservoir sluicing. Reservoir sluicing is passing incoming sediment-laden water through the reservoir by discharging high flows to enable sediment to move past the dam without depositing.
The analysis of these two strategies showed that the maximum sediment load increase is 1-3 Mt as a result of cancelling planned dams and 2-3 Mt due to reservoir sluicing. This means a very small increase for the deposition in the Mekong Delta (4% deposits). Therefore, the sediment load increase was considered unsatisfactory, suggesting that these strategies are not providing the solution for the Mekong Basin.
The results indicate that effective sediment management strategies are urgently needed and that more research is needed into the effects of other strategies on the silt and clay load in the Mekong Delta.
This project set out to investigate the accuracy of the MCP procedure under different configurations. Three comparative studies have been done in this project. Firstly, the attainable accuracy with either nearby MET-station data or ERA5 reanalysis data as a long-term reference source is assessed. Secondly, the use of different regression types for forming the relationship between target and reference data in the MCP procedure is assessed. Lastly, the accuracy achieved with standard MCP is compared to that achieved with a new wind resource estimation method, the method of analogs. The accuracy of the different configurations is assessed through the ability to accurately predict a period of wind speed values measured at 35 sites located in different terrain types. The predictions are evaluated using metrics such as the coefficient of determination, the root mean square error, the mean absolute error and the mean bias error.
This study found that ERA5 reanalysis data can serve as a reliable alternative to observed MET-station data. Generally, using ERA5 reanalysis data as a reference source always led to more accurate predictions then a MET-station reference source if the Pearson correlation between target and MET-station is lower than 0.8, and for offshore targets. If the Pearson correlation between target and MET-station reference is higher than 0.9, the achieved accuracy with either the MET-station or ERA5 data as a long-term reference is similar and depends on specific site conditions. In terms of regression methods it was found that the Matrix method, using the target site sectors for determining the regression parameters, generally outperforms other regression methods in terms of accuracy when determining the mean wind speed. Lastly, the method of analogs, a recently developed wind speed estimation method, yielded a similar prediction accuracy to standard MCP.
It should be noted that the different regression methods in employed in MCP all exhibited very similar prediction outcomes, with an average absolute difference in the predicted mean wind speed between the best and worst performing regression methods of only 0.046 m/s. Furthermore, the performance of the method of analogs in terms of accuracy improves with a longer concurrent period during which the relationships are formed. This project employed relatively short concurrent periods for certain targets, which may have contributed to sub-optimal performances of the method of analogs.","MCP; measure-correlate-predict; wind resource assessment; method of analogs; wind energy","en","master thesis","","","","","","Double degreein Electrical Engineering | Sustainable Energy Technology and Aerospace Engineering | Wind, Power and Economics","","","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:bec1494e-96a3-4cd5-b88e-32b5c6b3ce9c","http://resolver.tudelft.nl/uuid:bec1494e-96a3-4cd5-b88e-32b5c6b3ce9c","Sustainability Integration in Engineering Practice: A Comparative Life Cycle Assessment Study for the Case Study of a Wing Rib","Bakshi, Jaskrit (TU Delft Aerospace Engineering)","Villegas, I.F. (mentor); de Bruijn, Thomas (mentor); Bergsma, O.K. (graduation committee); Sinke, J. (graduation committee); Delft University of Technology (degree granting institution)","2023","Having seen exponential growth in demand for air travel, the aviation industry has found itself trying to find a balance between economic growth, technological development, and environmental sustainability. This saw a shift in attention towards materials such as fiber reinforced composites, predominantly thermoset in the past with higher strength-to-weight fractions. Relatively recent was the introduction of high-performance fiber reinforced thermoplastic polymer composite materials possessing more promising prospects of circularity in addition to the lightweighting capabilities. But as is, these only form for qualitative claims with no indication on how the ecological effects would pan out over the life cycle phases objectively, as well as on a relative scale.
Extending beyond the orthodox considerations and measures of aircraft performance, life cycle assessment studies encompass a comprehensive analysis of the environmental impact associated with aerospace products through the various phases of their life cycle including material extraction/production, manufacturing, operation, and the respective end-of-life treatment. The primary objective is to quantify the environmental impact of the system, offering a holistic view of the emissions, energy demand, and resource consumption.
To this end, this study constructed a comparative environmental profile, modelling for five material/manufacturing systems, namely numerically machined aluminium alloy, autoclave cured and resin transfer molded carbon fiber reinforced epoxy, autoclave consolidated, and press consolidated carbon fiber reinforced Polyetherketoneketone (PEKK) over the cradle-to-gate and the cradle-to-end of service phases in an attempt to find the best variant from an environmental perspective, while also adding a novel, semi-quantitative, robust framework of data quality assessment to the state-of-the-art.
The characterization results, under the assumption of each scenario yielding a product of the same mass and equal importance being given to each impact category (equal weighting), indicated the press consolidated carbon fiber reinforced PEKK product to be the scenario with the lowest impact over the cradle-to-gate (including only material production/extraction and product manufacturing). Over the cradle-to-end of service phases (including material production/extraction, product manufacturing, and the operational phase of the aircraft), the operational phase was observed to have an exponentially larger impact compared to the other life cycle phases causing the comparative profile to homogenize. This was reiterated by outcomes of the performed contribution analyses. Sensitivity analyses were conducted to explore the environmental benefits of lightweighting and processing waste optimization (buy-to-fly ratios quantifying the relative, quantitative benefits of lighter products and leaner manufacturing systems.
The objective of this research is to determine the optimal retention time for the biofilter to achieve the best water quality while maximizing the total amount of water to be recharged by controlling the pump. This thesis includes water quality measurement and water quantity simulation. In the water quality part, the performance of the biofilter at different retention time (2, 6, 16, and 24 hours) is evaluated in terms of the removal efficiency of turbidity, nutrients (nitrate and phosphorus), dissolved and particulate metals (Mn, Ca, Mg, Ba, Zn), UV254 and DOC with two different influent types (surface water and stormwater). In the water quantity part, Cromvliet Park, with an 8000 m2 collection area, was modelled using Python and SWMM to operate the biofilter with various retention time under one year of rainfall data (total rainfall 731mm). This modelling was done to calculate the total water volume available for recharge. The sections on water quality and quantity were integrated by controlling and evaluating the biofilter based on the retention time.
The results indicate that the efficiency of the biofilter's pollutant removal is influenced by several factors. Turbidity (40-90%) is effectively removed by the filtration in the biofilter. Nitrate removal efficiency was 12-49% with short retention times (2-6 hours) but fluctuated with longer durations (16-24 hours), decreasing to -84-13% and then changing to -6-0%. Measurements of dissolved oxygen in the effluent indicated that an increase in nitrate removal efficiency due to nitrification happened with longer retention time. For dissolved zinc, removal efficiency ranged from 10-60% with stormwater influent and 0-100% with surface water because of the adsorption competition of metals. Combined with the water quantity calculations performed in SWMM, it is advisable to set the optimal retention time for the biofilter at 4–6 hours. This duration allows for the maximization of water reuse while maintaining high nitrate removal efficiency.","Bluebloqs; Biofilter; Retention time; SWMM","en","master thesis","","","","","","","","2024-12-20","","","","Water Management","",""
"uuid:33f52b32-3128-4bc3-942a-4e31e849430b","http://resolver.tudelft.nl/uuid:33f52b32-3128-4bc3-942a-4e31e849430b","Modelling and sizing of an offshore hydrogen production value chain connected to the Port of Rotterdam","Breedijk, David (TU Delft Electrical Engineering, Mathematics and Computer Science)","van Wijk, A.J.M. (mentor); Lukszo, Z. (mentor); de Jong, W. (graduation committee); Zaaijer, M B (graduation committee); Frowijn, L.S.F. (graduation committee); van der Heijden, E. (graduation committee); Delft University of Technology (degree granting institution)","2023","As part of the Dutch government’s ambitions to realise significant offshore wind energy capacity (70 gigawatts (GW) by 2050), the Port of Rotterdam is to become a hydrogen hub for North-Western Europe. To achieve this, it is expected that around 20 megatonnes (Mt) of hydrogen could be throughput in the Port of Rotterdam, out of which 2 Mt will be produced locally from offshore wind farms. Current offshore wind farms use high voltage electricity cables to transport energy to shore, but could, in the future, also transport energy in the form of hydrogen to shore via a transport infrastructure.
The objective of this thesis is to investigate the techno-economical feasibility of an offshore hydrogen production value chain connected to the Port of Rotterdam. The technical analysis gives insights into the possible technologies that can be used for the offshore value chain. It will also look at the technical feasibility of system integration in the Noth Sea's energy system. The economic analysis gives insights into the economic feasibility of the offshore hydrogen production value chain. The total costs are of importance, as well as the levelised cost of hydrogen.
In this thesis, a qualitative literature study maps the different possibilities per component of the value chain. A decision framework is then used to discuss the best possibility per component and to build three promising designs. These designs are then modelled in MATLAB to size their components. With the model’s output, a cost analysis can be done to determine whether such a value chain would be feasible compared to other ongoing projects. A special focus will be put on the Port of Rotterdam, to which the value chain will be connected.
The offshore decentral configuration is found to be the best-performing design based on assessments through a multi-criteria decision analysis, a technical model and a financial model. It is, therefore, the most promising design.
This project aims to develop and characterize a green and sustainable bio-composite system, to overcome existing application challenges. The constituent materials include a bio-resin extracted from seaweeds and Unidirectional Flax fibers as reinforcements to stiffen and strengthen for semi-structural applications. Although alginates have been studied in-depth for their biomedical applications, their potential as a bio-based matrix for biocomposites has not yet been explored.
In addition to the materials used in the composite preparation, the processing technique significantly impacts the final properties of the composite. Therefore, in the first half of the work, thorough research was conducted to study the constituent properties for their processing. The second half of the work defined a new approach to manufacturing bio-composites from natural constituents. The corresponding analysis useful for product design are thoroughly demonstrated in this thesis.
However, using natural fibers in composites and water alginate soluble matrices has three main concerns: the fiber/matrix interaction and their sensibility to moisture absorption and residual water within the composite structure. Their surfaces can be modified using physical and/or chemical methods to improve the bonding between fibers and matrix. In most studies cited in the literature, the chemical modifications employed are synthetic and toxic. It would be ideal if the chemicals used to modify natural fibers were bio-based and preserved the biodegradable nature of natural fibers.
The development of an optimized seven-step manufacturing approach is a key innovation for water removal, to enhancing fiber reinforcement and boosting overall composite performance, particularly in the use of flax fibers. This approach is notable for its novelty and challenge, as evidenced by the limited literature on the subject. It focuses on achieving sufficient impregnation by utilizing low water percentages in resin, specifically around 7\%, and applying appropriate consolidation pressure and temperatures. The most effective results were observed at 5 MPa and 95°C, which facilitated homogeneous plasticization and mouldability. Additionally, the method of wet/dry cycling, incorporating pre-soaking and heating, has proven beneficial in providing dimensional stability to flax fibers and limiting water absorption, further contributing to the technique's effectiveness.
Analytical techniques like microscopy and SEM reveal promising compatibility between components. No degradation of the bio-resin or the fibers relatable to the heat press was identified.
Finally, the research aimed to establish a meaningful relationship between the critical process variables and the properties of the bio-composite, with the ultimate goal of optimizing the production process and enhancing the quality of the final product by varying the fiber volume fraction within the range of 41-47\%.
The maximum tensile and flexural strengths achieved were 219MPa and 56Mpa, respectively. The elastic tensile and bending moduli in the composites were approximately 6.64GPa and 1.83GPa, respectively.
However, the observed properties fell below the predicted values for the biocomposite system, which were calculated using the rule-of-mixtures and Halpin-Tsai methods. Nonetheless, the experimental data confirm that these biocomposites can be used as secondary structural elements. The observed discrepancy was due to the presence of huge voids further leading to poor adhesion.","biocomposites; Green composites; biodegradable","en","master thesis","","","","","","","","2024-06-30","","","","Materials Science and Engineering","",""
"uuid:219a5430-cc06-4afa-a680-ab1659cd5396","http://resolver.tudelft.nl/uuid:219a5430-cc06-4afa-a680-ab1659cd5396","Cell Micro-Rheology Under Hypergravity Conditions","van Rijthoven, Sharon (TU Delft Mechanical, Maritime and Materials Engineering)","Koenderink, G.H. (mentor); van Loon, Jack (graduation committee); Delft University of Technology (degree granting institution)","2023","","","en","master thesis","","","","","","","","","","","","Biomedical Engineering","",""
"uuid:03cd10a2-4f67-41cc-aa11-ead03aeab4a7","http://resolver.tudelft.nl/uuid:03cd10a2-4f67-41cc-aa11-ead03aeab4a7","Towards a new Existenzminimum: defining principles for the co-design of affordable collaborative housing","Dos Santos Vieira Brysch, S.L. (TU Delft Real Estate Management)","Gruis, V.H. (promotor); Czischke, D.K. (copromotor); Delft University of Technology (degree granting institution)","2023","This thesis brings forward the design dimension, and, more specifically, co-design, to the study of housing affordability. Co-design occurs when end-users and professionals work together towards a common goal. It is a process often applied in collaborative housing, an umbrella concept encompassing different housing forms based on collective self-organisation and collaboration, where residents choose to share certain spaces. The aim of this research is to assess if and how co-design processes applied in collaborative housing may reduce building costs, thereby making these housing projects not only affordable, but even more affordable than mainstream housing. It does so by combining a case study approach with a building costs simulation. Findings indicate that co-design decisions based on a collective self-redefinition of Existenzminimum (minimum dwelling) affect the housing layout and contribute to reduce building costs. By conceptualising housing design through the lenses of affordability, this thesis highlights the understated role of architectural design and building costs as key components in the study and provision of affordable housing solutions; and enriches the existing body of knowledge on affordable collaborative housing. Moreover, it draws attention to the way some outdated building regulations and standards hamper design innovation in housing. This research ends up with a set of general principles for the co-design of affordable collaborative housing. These design principles may assist professionals supporting co-design and, more importantly, people who want to design, build and live in a collaborative manner.","Collaborative housing; Affordable Housing; Co-Design; Existenzminimum; Housing design","en","doctoral thesis","A+BE | Architecture and the Built Environment","978-94-6366-788-3","","","","","","","","","Real Estate Management","","",""
"uuid:623636cb-6954-4a9f-8ff3-fcb9dd0f22c5","http://resolver.tudelft.nl/uuid:623636cb-6954-4a9f-8ff3-fcb9dd0f22c5","Daily Life Activity Recognition with a Head Mounted IMU on Older Adults: Which Features to Extract?","Raizman, Omri (TU Delft Mechanical, Maritime and Materials Engineering)","van der Kruk, E. (mentor); Raman, C.A. (graduation committee); Waterval, Niels (mentor); Delft University of Technology (degree granting institution)","2023","As the population aged 65 and above increases, falls among these older adults emerge as a significant public health concern, leading to disabil- ities and economic burdens. Preventative strategies and personalized fall risk assessments are essential for mitigating fall risks. Human Activity Recognition in early fall risk detection by monitoring everyday ac- tivities in older adults could assess patients fall risks. However, current literature has overlooked the older adult demographic by only measuring adults younger than 65, under representing the older population. This research specifically focuses on identifying key features from head-mounted Inertial Measurement Unit (IMU) data using machine learning to classify Sit-to-Walk (STW) and Walk-to-Sit (WTS) move- ments, which are commonly associated with high risk of fall. In addition these movements can be essential in monitoring changes in performance to asses fall risk. We analyzed five activities STW, WTS, Sitting, Swing phase, and Others. Using three feature selec- tion methods (Mutual Information Gain, ANOVA, Recursive Feature Elimination) on 116 extracted fea- tures we were able to rank the features and select the top ten. The study then evaluated the accuracy of three classifiers (Logistic Regression, Random For- est, and K-Nearest Neighbor or Support Vector Ma- chine) with these features. Results indicated that the ANOVA and Random Forest classifier combination achieved the highest total accuracy of 95%, with Ran- dom Forest performing exceptionally well in STW and WTS classifications, reaching up to 81% accu- racy. Commonly selected features across all methods included the accelerometer’s maximum x-axis mea- sured and its energy in both time and frequency do- mains. This model’s performance is comparable with existing literature and validates its effectiveness in fall risk detection.
Through operational analysis of the pilot plant, it has been determined that replacing half of the primary raw material with galvanized steel scrap as a secondary source in the HIsarna process is feasible. This substitution would result in a significant reduction in the injection of fine iron ore. Another advantage is the continuous evaporation of zinc from the scrap surface, accumulating in the off-gas dust, which can later be separated and recovered. In contrast to the blast furnace route, the zinc element does not form a circulating loop inside the reactor but is converted to the oxidized/ferrite form, ultimately ending up in the dust bag and filters.
However, plant measurements and laboratory analysis of the HIsarna dust reveal that the evaporated zinc primarily reacts with available oxygen and iron oxides to form zinc ferrite. This necessitates additional pre-processing steps before feeding into the zinc smelting unit, incurring extra costs. Consequently, the formation of ferrite is deemed undesirable.
In a nutshell, this thesis focuses on developing a precise computational fluid dynamic (CFD) model to predict the behaviour of the HIsarna off-gas system. This model is crucial for predicting temperature and composition profiles within the off-gas system, particularly in zones where data are not measured at the pilot plant. The possibility of zinc ferrite formation reduction and off-gas system is investigated using plant measurements, CFD data analysis, and thermodynamic calculations. Furthermore, the developed CFD model is utilized to propose modification/optimization of the process, reducing iron ore dust escaping the system, reducing post-combustion oxygen consumption, optimizing post-combustion lance, and off-gas system scale-up.
Chapter 1 of the thesis is dedicated to a brief history of ironmaking and introduces the HIsarna process in detail, as well as the research focus and thesis structure. Chapter 2 focuses on establishing and validating a CFD model and offers a detailed description. Chapter 3 provides an extensive discussion of the model selection and sensitivity analysis. This chapter primarily delves into critical insights regarding the reasons behind the choice of sub-models within the CFD model. Flow analysis of the off-gas system is presented in Chapter 4, and in Chapter 5, the behaviour of the escaped ore entering the off-gas system is investigated, and potential solutions to mitigate injected ore losses from the off-gas system are discussed. The modified geometry introduced in Chapter 5 is subjected to analysis using the same validated CFD model, ensuring its effective operation within the entire off-gas system. These findings are discussed in Chapter 6 of the thesis. In Chapter 7, the formation of zinc oxide and zinc ferrite are investigated in the original and modified geometry of the off-gas system, and possible solutions to reduce the ferrite formation are proposed. In Chapter 8, a modification to the oxygen lance is proposed to enhance the combustion of the CO-H2 mixture. This modification involves using a fluidic oscillator instead of injecting oxygen through a conventional nozzle. The results demonstrate an improvement in CO-H2 combustion in the reflux chamber. The proposed geometry is constructed and implemented in the reflux chamber for further evaluation and is discussed in detail.
In Chapter 9 (Part 3), the CFD model developed for the pilot plant is employed to conduct a CFD-based scale-up of the off-gas system to the industrial scale. Within this chapter, the optimized geometry and recommended operating conditions are presented. Conclusions, remarks, and recommendations are presented in the final chapter of the thesis (Chapter 10).","Computational Fluid Dynamics; Discrete Element Method; Finite Element Method; Discrete Phase Model (DPM); HIsarna Iron Making; Particle flow modelling; CFD-assisted scale up; Zinc ferrite formation; Thermodynamic analysis; Post combustion chamber; Combustion; Fluidic oscillator","en","doctoral thesis","","978-94-6384-517-5","","","","","","","","","Team Yongxiang Yang","","",""
"uuid:7d3c6107-812e-458e-bd11-04f5c1e5931a","http://resolver.tudelft.nl/uuid:7d3c6107-812e-458e-bd11-04f5c1e5931a","Driver and Pedestrian Mutual Awareness for Path Prediction in Intelligent Vehicles","Roth, M. (TU Delft Intelligent Vehicles)","Gavrila, D. (promotor); Kooij, J.F.P. (copromotor); Delft University of Technology (degree granting institution)","2023","This thesis addresses the sensor-based perception of driver and pedestrian to improve joint path prediction of ego-vehicle and pedestrian based on mutual awareness in the domain of intelligent vehicles.
According to the World Health Organization (WHO), more than half of global traffic deaths are among Vulnerable Road Users (VRUs), such as pedestrians and riders, and human error is still a major cause of accidents. This motivates paying special attention to pedestrians and drivers while they are interacting in traffic. For the foreseeable future, the reality on the road (and the accident numbers) will largely be determined by Advanced Driver-assistance Systems (ADAS) where the driver is still required to keep the eyes on the road. To that end, the scope of this thesis resides within ADAS and driving automation up to (including) autonomy level 3 as defined by the Society of Automotive Engineers (SAE). While current ADAS consider pedestrians and the driver individually, their mutual awareness has not been leveraged to improve path prediction and thereby road safety. This thesis presents a framework that estimates driver head pose from driver camera images, estimates pedestrian location and orientation from exterior camera images and lidar point clouds, uses this information over time to reason about driver and pedestrian mutual awareness, and performs joint probabilistic path prediction of ego-vehicle and pedestrian to assess collision risk.
Deep neural networks demand a large training set to tune the vast amount of parameters. This thesis introduces DD-Pose, the Daimler TU Delft Driver Head Pose Benchmark, a large-scale and diverse benchmark for image-based head pose estimation and driver analysis. It contains 330k measurements from multiple cameras acquired by an in-car setup during naturalistic drives. Large out-of-plane head rotations and occlusions are induced by complex driving scenarios. Precise head pose annotations are obtained by a motion capture sensor and a novel calibration device. The new dataset offers a broad distribution of head poses, comprising an order of magnitude more samples of rare poses than a comparable dataset.
Utilizing the dataset, this thesis presents intrApose, a novel method for continuous 6 degrees of freedom (DOF) head pose estimation from a single camera image without prior detection or landmark localization. intrApose uses camera intrinsics consistently within the deep neural network and is crop-aware and scale-aware: poses estimated from bounding boxes within the overall image are converted to a consistent pose within the camera frame. It employs a continuous, differentiable rotation representation that simplifies the overall architecture compared to existing methods. Experiments show that leveraging camera intrinsics and a continuous rotation representation (SVDO+) results in improved pose estimation compared to intrinsics agnostic variants and variants with discontinuous rotation representations. Driver head pose of naturalistic driving is biased towards close-to-frontal orientations. Training with an unbiased data distribution, i.e., a more uniform distribution of head poses, further reduces rotation error, specifically for extreme orientations and occlusions.
In addition to considering the inside of the vehicle, this thesis also focuses on the outside environment and presents a method for 3D person detection from a pair of camera image and lidar point cloud in automotive scenes. The method comprises a deep neural network that estimates the 3D location, spatial extent, and yaw orientation of persons present in the scene. 3D anchor proposals are refined in two stages: a region proposal network and a subsequent detection network. For both input modalities high-level feature representations are learned from raw sensor data instead of being manually designed. To that end, the method uses Voxel Feature Encoders to obtain point cloud features instead of widely used projection-based point cloud representations. Experiments are conducted on the KITTI 3D object detection benchmark, a commonly used dataset in the automotive domain.
Eventually, the output provided by the methods of the former chapters, namely, driver head pose and 3D person locations, are leveraged by a novel method for vehicle-pedestrian path prediction that takes into account the awareness of the driver and the pedestrian of each other’s presence. The method jointly models the paths of ego-vehicle and a pedestrian within a single Dynamic Bayesian Network (DBN). In this DBN, subgraphs model the environment and entity-specific context cues of the vehicle and pedestrian (incl. awareness), which affect their future motion. These sub-graphs share a latent state which models whether the vehicle and pedestrian are on collision course. The method is validated with real-world data obtained by on-board vehicle sensing, spanning various awareness conditions and dynamic characteristics of the participants. Results show that at a prediction horizon of 1.5 s, context-aware models outperform context-agnostic models in path prediction for scenarios with a dynamics change while performing similarly otherwise. Results further indicate that driver attention-aware models improve collision risk estimation compared to driver-agnostic models. This illustrates that driver contextual cues can support a more anticipatory collision warning and vehicle control strategy.
The main conclusions and findings of this thesis are: using a measurement device with a per-subject calibration procedure simplifies the data acquisition process to obtain a broad distribution of head poses. Using an intrinsics-aware head pose estimation method with a continuous rotation representations allows for a simple architecture that yields robust head pose estimates across a broad spectrum of head poses. Modeling of both driver and pedestrian mutual awareness in a unified DBN improves joint probabilistic path prediction compared to driver-agnostic models. Additionally, it provides explainability for model parameters and interpretability of the internal decision making process. Further research can be conducted to understand the behavior of humans inside and outside an intelligent vehicle. Two major trends go towards integrating uncertainties into the components and combining them to a system that can be trained end-to-end from raw sensor data to predicted paths. Future work would greatly benefit from representative, worldwide, naturalistic, multi-sensor, temporal data which cover the outside environment as well as the inside of the vehicle - ideally shared across research institutions and companies.","Head pose estimation; Head pose dataset; Person detection; Ego-vehicle path prediction; Pedestrian path prediction; Intelligent vehicles; Automated driving","en","doctoral thesis","","978-94-6384-502-1","","","","","","2023-12-20","","","Intelligent Vehicles","","",""
"uuid:a68190dd-6e9c-426b-bbcb-4ea1f5910c82","http://resolver.tudelft.nl/uuid:a68190dd-6e9c-426b-bbcb-4ea1f5910c82","Exploring the use of Extended Reality for user experience design in product-service systems","Li, M. (TU Delft Applied Ergonomics and Design)","van Eijk, D.J. (promotor); Albayrak, A. (copromotor); Delft University of Technology (degree granting institution)","2023","This dissertation aims to explore the use of extended reality (XR) as an approach to developing user experience (UX) for product-service systems. It included eight chapters to explore the research question: “How can designers use extended reality to develop the user experience for product-service systems?”
Chapter 1 introduces three immersive experiences in user experience studies as examples and explains three relevant research topics - Product-service systems, User Experience, and Extended Reality. By reviewing the XR applications in both in design practices and in literature, the author proposed e the aim, the research question, and six sub-questions of this dissertation, followed by the explanation on theoretical backgrounds and research methodologies.
Chapter 2 answers sub-question 1 about the essence of immersive experience from users’ and designers’ viewpoints, thus proposes a user-centered model of immersive experience from literature and case analysis; then the author maps currently available XR platforms concerning the categories of experiences.
Chapter 3 firstly answers the sub-question 2 by reviewing state-of-the-art XR technologies for UX studies; then the author proposes a process to prototype experiences via XR to develop positive experiences for product-service systems.
Chapter 4 investigates three case studies to understand how to ideate concepts via
XR at the early design stage, specifically in conceptualization. In addition, the studies also compare the influence of different viewpoints and ways of interaction on the perception of “being comfortable”.
Chapter 5 examines how to assess experiences via XR across user groups and
concentrates on competence-related experiences. This chapter contains three case studies in the context of true-to-life surgical training where a successful surgery depends both on proficient psycho-motor skills and mature self-management of surgeons. In addition, these studies also observe the influences of proficiency, cultural backgrounds, and technology familiarity on the perception of competencies.
Chapter 6 scrutinizes how to facilitate remote collaboration via XR. This chapter
covers two studies in the context of remote teamwork. Given relatedness as a universal need, these studies focus on the influences of different interfaces, either immersive or non-immersive, on the perception of the co-location, as well as task loads, usability, and presence.
Chapter 7 first reviews the lessons learned from the case studies and then probes how design teams integrate immersive experiences into their practices. Hence, four co-creation studies were developed which are in line with the conceptual process in Chapter 3. Section 7.2 to Section 7.5 focus on designer's intention, designerly thinking, prototyping, and co-design via XR respectively.
Chapter 8 reflects on each sub-question from an overarching perspective, and then summarizes three sets of recommendations for design stakeholders who are interested in integrating immersive experiences in their work. This chapter then envisions a concept of a co-design community via immersion - ‘Design Metaverse’. At the end, the limitations of this work are discussed, as well as future research directions.","extended reality (XR); user experience design; Product-Service Systems (PSS)","en","doctoral thesis","","978-94-93353-48-0","","","","","","","","","Applied Ergonomics and Design","","",""
"uuid:ccc64317-4955-4267-9fbf-987042098876","http://resolver.tudelft.nl/uuid:ccc64317-4955-4267-9fbf-987042098876","Understanding How Trace Visualizations Influence Exploration Behaviors in VR","Tan, Zhuowen (TU Delft Industrial Design Engineering; TU Delft Human-Centered Design)","Huisman, G. (graduation committee); Jaśkiewicz, T.J. (mentor); El Ali, Abdallah (mentor); Delft University of Technology (degree granting institution)","2023","Understanding how the end users, ordinary citizens, experience designed public spaces is fundamental in the field of urban design. Virtual Reality (VR) technologies significantly enhance the ease of evaluating public space designs by creating virtual simulations. This allows users to immerse themselves more deeply in the space compared to traditional screen-based presentations. However, the true experience of space design only occurs once it is physically constructed. Designers still face challenges in effectively investigating how citizens might interact with the future space. In evaluating public space designs, one obstacle is that users can only provide feedback based on individual experiences, lacking knowledge of how others have perceived or used the space, which contrasts with the real world situations where people experience and perceive public spaces with the association with how others’ experiences.
Trace visualizations have been used to analyze user behaviors. Visualizing traces of previous users unlocks possibilities of enhancing curiosity and meaningful exploration of the space, which could inspire more association about use scenarios and a deeper understanding of the spatial properties, and eventually benefit the evaluation outcomes.
This project explored the influences of visualizing human traces on users’ explorative behaviors in virtual reality space. We started with conducting interviews with urban designers to understand the utilization of traces in the processes of public space design and their perspectives regarding implementing trace visualizations to support public space design evaluation. Insights from the interview informed the selection of traces for the experiment including user pathways, gathering situation, full-body motion, and space atmosphere. Subsequently, we integrated trace visualizations into a VR shopping street and conducted the experiment with 20 participants to evaluate the impacts of each trace visualization on user exploration. The outcomes from interviews and operational activities undertaken by participants revealed exploration patterns associated with each type of the trace visualizations and related findings concerning user perceptions of the trace visualizations. The project concluded with the implications for implementing trace visualizations in VR environments and the limitations of the research.","Virtual Reality; Trace; Visualization; Explorative Behavior; Urban Design; Public Space Design Evaluation","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:a1123f0a-3995-4675-8ef4-02c0fe5a4686","http://resolver.tudelft.nl/uuid:a1123f0a-3995-4675-8ef4-02c0fe5a4686","Multimodal city logistics using waterways in Amsterdam: proof-of-concept of a two-echelon distribution network","Bijvoet, Bas (TU Delft Mechanical Engineering)","Atasoy, B. (mentor); Karademir, C. (mentor); Ludema, M.W. (mentor); Jovanova, J. (graduation committee); Meindertsma, Thomas (graduation committee); Vernooij, Thomas (graduation committee); Delft University of Technology (degree granting institution)","2023","This study focuses on two-echelon synchronized logistics in a multimodal distribution network for integrated road-based and waterborne transportation motivated by practical city logistics challenges. To evaluate the feasibility and requirements of a multimodal transport system as a potential future logistics solution for supplying hotels, restaurants, and cafés (HoReCa) in the city center of Amsterdam, we propose a methodology to evaluate the effect of various satellite service network designs, fleet sizes of vessel and street vehicles, and city access time window constraints (permitted working hours that can be set by the municipality through policies). To tackle the complexity of the problem, a decomposition-based heuristic is developed to solve large-size instances for a rich 2E-VRP variant. The decomposition-based heuristic consists of three main phases: a location phase for determining satellite locations, an allocation phase for establishing assignments of satellites and customers, and a routing phase for solving the routing problem given operational settings. In addition, we propose various modeling approaches to represent system designs with different operational limitations in practice. First, we consider two transshipment types: one-to-many and one-to-one transshipments. The transshipment type is related to satellite resources in terms of space availability and lifting capabilities. Secondly, we propose two simulation-optimization frameworks for iteratively configuring the workload of and workforce at satellites. We demonstrate the methodology by conducting a case study for supplying over 1600 HoReCa in the city center of Amsterdam. The results indicate that balancing the workload of satellites is critical for scenarios with few permitted working hours. By configuring the workforce at satellites, a good balance between the number of vessels, street vehicles, and street-level distance is found for scenarios with more permitted working hours. We show that the transshipment type significantly affects the service level and system requirements to meet customer demand, with a sensitivity analysis on transshipment times at satellites indicating significant benefits for reduced transshipment time in the case of one-to-one transshipments. Moreover, the computational experiments show several trade-offs between the required number of satellites, vessels, street vehicles, and permitted working hours to meet customer demand.","Two-echelon vehicle routing; City logistics; Multimodal transportation; Service network design; Simulation-optimization","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Multi-Machine Engineering","",""
"uuid:09e330f6-40f0-4c61-83c3-c698905359ea","http://resolver.tudelft.nl/uuid:09e330f6-40f0-4c61-83c3-c698905359ea","Develop and evaluate a web-based design guide for improving the digital patient experience","Wang, Yun (TU Delft Industrial Design Engineering)","Wang, T. (mentor); Rietjens, J.A.C. (graduation committee); Delft University of Technology (degree granting institution)","2023","You, I and almost everyone deal with illness under a certain condition. As digital health is becoming ever more widespread nowadays, this change shapes a new understanding of our medical experience. Consider how these new digital tools might affect patient experience becomes more crucial for everyone’s life. Four studies, aiming at understanding and enhancing the patient experience, thus become the foundation of this project.
However, the transition of academic research knowledge into practical design information often faces obstacles (Zielhuis et al., 2022a). Challenges include effectively teach-ing freshmen (Hoadley & Cox, 2008), selecting the right formats, and successfully conveying academic knowledge in a practical context (Stappers and Giaccardi, 2017). As a result, despite the fact that the primary research potentially enables healthcare designers to enhance the digital patient experience, whether practitioners can benefit from these academic findings is still unclear. Therefore, to further transfer the primary research to support design education and best practices for improving patient experience in digital health, as well as increase the accessibility and applicability of the primary research (Daniluk and Koert, 2015; Cook, D. A., 2007), an exploration starts.
Desk research and literature research are done to define the project’s scope and make a concrete goal. Design guidelines are considered since they play a crucial role in leading designers to success. Through learning and following effective design guidelines, designers can significantly enhance the quality of their design outcomes (Fu, Yang, & Wood, 2016). To transform the primary research into design guidelines, nine qualities should be considered in the creation and evaluation process. Additionally, the website is an appro-priate method of transferring information (Daniluk and Koert, 2015; Cook, D. A., 2007). When creating a website, usability, accessibility, and consistency need to be considered.
It is defined that the primary research should be transformed into design guidelines based on a website platform, the design goal therefore is defined as: To transform the primary research into a good and usable web-based design guide, enabling healthcare designers to utilize the primary research to improve the digital patient experience. To achieve this goal, design activities should be conducted to ensure the website’s usability, consistency, and accessibility, with the guide content’s clarity, efficacy, and credibility.
Through design activities such as walkthroughs and case studies, an initial minimum viable (MVP) website is developed. An evaluation workshop makes clear that the website partially meets
its design objectives and suggests a need for improvement in content clarity and efficacy and website usability. Following this feedback, an iteration is developed, resulting in a complete website design. A small-scale usability test validates the in-crease in content clarity, credibility, and efficacy, with overall usability slightly declining. Hence, the website is iterated again.
In conclusion, there was proof that the final design met the goal of having expected clarity, efficacy, credibility, color accessibility, and internal and external consistency. The final SUS score was 59.5 out of 100, which was acceptable but implied room for improvement (Bangor, Kortum, & Miller, 2009).","Digital Patient Experience; Website Design; UX Design","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:39040fef-68a7-41d1-8c12-8352cc45cc6b","http://resolver.tudelft.nl/uuid:39040fef-68a7-41d1-8c12-8352cc45cc6b","The introduction of augmented reality: At the Oral & Maxillofacial Department of the University Medical Center Utrecht","Nicolai, Noa (TU Delft Mechanical, Maritime and Materials Engineering)","van Walsum, Theo (mentor); Kortes, Joël (graduation committee); Kienhuis, Maartje (graduation committee); Janssen, Nard (mentor); Benmahdjoub, Mohamed (graduation committee); Delft University of Technology (degree granting institution)","2023","The complexity and interdependency of hospital activities make it challenging to seamlessly integrate new technologies into clinical routines, especially with various stakeholders involved. Considering contextual factors when implementing innovations has been recognized as critical to success. This highlights the significance of an approach that focuses on integrating technology with the existing healthcare culture and motivating the context to change, rather than focusing on technology alone. Therefore, the aim of this thesis is to provide a method to ensure the clinical context is considered when developing a new technology. This approach is put in practice by utilizing it to introduce augmented reality (AR) at the oral and maxillofacial surgery (OMFS) department of the University Medical Center (UMC) Utrecht, to provide new insights on how to better align the technology with clinical needs and to familiarize and motivate the medical team with the technology. This is done in close collaboration with the UMC Groningen. Currently, the UMC Groningen, UMC Utrecht, and the Center for Information Technology (CIT) of the University of Groningen are developing an AR surgical navigation system. The aim of the introduction is to provide valuable information for the further development of the system and to prepare and involve the clinical environment.
The approach used in this thesis is based on human-centered design and design-thinking. Furthermore, key factors for successful adoption found from previous research are considered. The approach consists of four main components. The first is to assign a med-tech innovation coordinator; someone with both a medical and technical background who will be responsible for driving adoption. Furthermore, it is an iterative three-step process: 1) Gain understanding; 2) Share understanding; 3) Actively engage stakeholders.
The application of this approach to introduce AR at the OMFS department of the UMC Utrecht has resulted in multiple positive effects. In clinical context it resulted in an understanding of the technology and its value, motivations to invest time in the system, and the establishment of a shared future perspective on the implementation of AR. Furthermore, valuable input from a clinical perspective is obtained, including confirmation of valuable system elements and new ideas/insights for the further development of the AR navigation system.
In conclusion, this thesis provides guidance for departments seeking to adopt new technologies based on a practical example. The methodology provides activities that facilitate the early introduction of technologies, ensuring the active involvement of the clinical context.","Augmented Reality; Surgical Navigation; Development; implementation","en","master thesis","","","","","","","","2025-12-01","","","","Technical Medicine","",""
"uuid:a583e92a-cfb6-4249-8875-94acc52e7260","http://resolver.tudelft.nl/uuid:a583e92a-cfb6-4249-8875-94acc52e7260","Constraining the Ephemeris and Interior Structure of Io using Space-Based Astrometry by JUICE","Zenk, Kai (TU Delft Aerospace Engineering)","Dirkx, D. (mentor); Fayolle-Chambe, M.S. (graduation committee); Delft University of Technology (degree granting institution)","2023","Owing to the assumed presence of sub-surface oceans, the Galilean satellites - Io, Europa, Ganymede, and Callisto - are among the most promising candidates for potential extraterrestrial habitats within our Solar System. To this end, the moons are going to be extensively studied by the upcoming JUICE and Europa Clipper missions. Ultimately, understanding the dynamics of the Jovian system is a means to shed light on the general existence and stability of these presumed habitable worlds as well as the formation and evolution of the entire Solar System. Yet, while the dynamics of Ganymede (in particular via the orbital phase of JUICE) and Europa (mainly via the various flybys of Europa Clipper) are going to be observed to an unprecedented level of accuracy, the absence of flybys of Io due to its harsh radiation-environment results in a significantly imbalanced data set. To stabilise the numerical data inversion, spaced-based imaging by the camera subsystem of JUICE is crucial to constrain the dynamics of Io.
However, while the analysis of orbital dynamics is usually performed with respect to the centre-of-mass (COM) of natural satellites, optical space-based astrometry provides measurements of the position of a body's centre-of-figure (COF), introducing a discrepancy between the dynamical and observational model. Explicitly accounting for the offset between the observed centre-of-figure and the propagated centre-of-mass during ephemeris estimation, however, ensures the consistency of the dynamical and observational model. In turn, this allows us to assess the extent to which optical space-based astrometric observations might either validate the merely indirectly obtained radio science data or contribute to the overall orbital solution of Io. Finally, obtaining a measure of the offset between the centre-of-figure and centre-of-mass yields an entirely new constraint on the interior structure and composition of Io.
In order to quantify the COF-COM-offset, we have simulated optical astrometric observations by JUICE and subsequently determined the formal uncertainties of the estimated offset using covariance analyses. Using suitably computed \textit{a prioir} covariance matrices, we have constrained our analyses to the averaged propagated formal errors of Io that would arise from the radiometric tracking set-up of JUICE and Europa Clipper. We have found that the contribution of optical space-based astrometry to the COF-COM-offset of Io and its estimated state highly depends on the observations' quantity, quality, and geometry. Thus, an algorithm for the selection epochs at which images are to be simulated based on the main drivers - the absolute uncertainties and relative geometries of a series of observations - of the formal errors COF-COM-offset has been developed. However, owing to the largely equatorial alignment of JUICE with respect to Io - observations of the in-plane contribution have been found to be obstructed by the brightness of Jupiter. To maximise the scientific return of optical space-based astrometry, in particular, astrometry during the high-inclination phase has proven beneficial.
Overall, significant constraints of the discrepancy between the centre-of-figure and centre-of-mass and the orbital solution of Io have been obtained. For an expectable number of about 1300~images being taken of Io, realistically attainable formal uncertainties in the estimated COF-COM-offset of no more than 300~metres have been obtained. Furthermore, since notable contributions to the orbital solution already occur for reasonable radio science true-to-formal-error ratios between two and five, we have concluded a high likelihood of space-based astrometry contributing to the orbital solution. This potential of space-based imaging to balance and contribute to the orbital solution of Io thus motivates future research concerning the offset between the centre-of-figure and centre-of-mass.","astrometry; centre-of-figure; ephemerides; planets and satellites: Galilean moons; methods: data analysis","en","master thesis","","","","","","","","2025-12-19","","","","Aerospace Engineering","",""
"uuid:2fd45eac-fdbf-4d30-a206-7fb06521a282","http://resolver.tudelft.nl/uuid:2fd45eac-fdbf-4d30-a206-7fb06521a282","WASP: a Wasp-inspired Surgery needle for Prostate cancer procedures: Design and prototyping of a low-friction actuation mechanism","Fung-A-Jou, Zola (TU Delft Mechanical, Maritime and Materials Engineering)","Bloemberg, J. (mentor); Breedveld, P. (mentor); Horeman, T. (graduation committee); Delft University of Technology (degree granting institution)","2023","Prostate cancer is the second most frequently diagnosed cancer in men. A minimal invasive treatment for prostate cancer is transperineal laser ablation (TPLA), which involves inserting a needle containing a laser fibre into the prostate to induce local cell death. The ovipositor of the parasitoid wasp offers a solution to challenges in TPLA, as the wasp can penetrate substrates with zero net external force, minimising the buckling risk and tissue damage. This paper presents the WASP, a design and prototype of a manually actuated needle for TPLA. The actuation mechanism of the WASP transfers a torque while allowing a low-friction translation in the positive y-direction, enabling the needle to travel through stationary tissue. An integrated cam mechanism allows repetitive motion of the needle rods actuated by a single rotation of the urologist. Evaluation of the WASP showed successful travelling through gelatin concentrations up to 15 wt%, a stiffness comparable to human tissue. The WASP generated a small net push force (Fpush = 0.18 N) and cannot be considered fully self-propelling. Nonetheless, the net push force is notably reduced compared to manual needle insertion and effectively prevents buckling. A performance experiment showed a lower average slip ratio compared to previous studies, which may suggest that a small net push force is beneficial if buckling is prevented. Future steps contain implementing user research and a steering mechanism, to continue innovating minimally invasive surgery for prostate cancer.","Bioinspiration; TPLA; Medical; Non invasive surgery; Buckling","en","master thesis","","","","","","","","2025-12-19","","","","Mechanical Engineering","",""
"uuid:a252877d-9f6e-43b4-97bd-51422d504b9f","http://resolver.tudelft.nl/uuid:a252877d-9f6e-43b4-97bd-51422d504b9f","Design and Implementation of the Power Electronic System for the Lunar Zebro rover","Hubers, Martijn (TU Delft Electrical Engineering, Mathematics and Computer Science)","Shekhar, A. (mentor); Gagic, Mladen (mentor); Bauer, P. (mentor); Verhoeven, C.J.M. (graduation committee); Delft University of Technology (degree granting institution)","2023","The small and lightweight Lunar Zebro rover must survive in the harsh lunar environment for several Earth days following its moon landing. The mission of the rover is to map the radiation environment on the moon. The success of the entire mission depends on the Power Electronic System (PES), which supplies power to all subsystems and charges the batteries using solar panels. The current PES of the Lunar Zebro rover does not comply with all mission-specific requirements and does not perform satisfactorily when integrated into the rover. Therefore, the need for a reliable PES that conforms to all requirements arises for the Lunar Zebro rover.
In this research, the design and implementation of an efficient, compact, and redundant PES for the Lunar Zebro rover is developed. First, the optimal Direct Current (DC) bus is designed to obtain a system with the highest efficiency. This is done by modelling the efficiency of the DC/DC converters for different bus voltages and estimating the overall losses in these converters during the deployment of the rover. Moreover, the effect of the bus voltage on the size of the passive components is investigated, and the bus voltage resulting in the most compact system is obtained. It is found that a 12 V bus results in the most efficient and compact system. No additional converter is required that regulates the 12 V output, and the inductance required for each converter is decreased compared to higher bus voltages.
Besides the DC bus design, redundancy methods are compared to obtain the best tradeoff between redundancy and footprint added. The two-phase interleaved converter was found to have only an 8.59% increase in footprint compared to single-phase converters, while failure in a switch, diode, input capacitor, and output capacitor are accounted for in each converter. Finally, the mode of operation that results in the highest efficiency is obtained by designing each converter and modelling the corresponding losses for Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) operation. For both the single-phase and two-phase interleaved converters hold that operating in CCM results in a significant increase in efficiency compared to DCM operation. Moreover, the PES utilising two-phase interleaved converters is more efficient during rover operation than the single-phase counterpart. However, charging is less efficient than for the single-phase counterpart. Simulink and LTspice simulations have been carried out to verify the operation of each converter. Finally, experiments on a functional prototype are carried out to provide experimental validation of the design.","EPS; DC/DC Converter; CCM; DCM; Buck Converter; Boost Converter; Buck-Boost converter; bidirectional converter; Lunar rover; Efficiency","en","master thesis","","","","","","","","","","","","Electrical Engineering","",""
"uuid:d6ca4e5b-fb44-40d1-8ee6-f420653e5870","http://resolver.tudelft.nl/uuid:d6ca4e5b-fb44-40d1-8ee6-f420653e5870","Mijn Hulplijn: An intervention to empower youngsters in decision making in (j)-GGZ therapy","Kreuk, Davy (TU Delft Industrial Design Engineering)","Pasman, G.J. (mentor); Brouwer, W. (graduation committee); Delft University of Technology (degree granting institution)","2023","Extensive waiting times for youth Mental Healthcare have a significantly negative effect on youngsters well-being. The Ministry of Public Health, Welfare and Sport (Ministry of VWS) therefore commissioned Shoshin to research the cause of waiting times in order to address them. Shoshin is a social design agency that believes waiting times are not only the result of a shortage of staff, but also of inefficiencies and ineffective elements in the youth care system. They aim to make strategic interventions to create true system change (Haarlemmer et al.).
This thesis aims to support Shoshin in their mission to reduce waiting times for youngsters. Youngsters are defined as 16 till 23 year people in this report.
Specifically, the aim of this graduation project is to come up with a design that helps youngsters get more appropriate care. According to Van der Bijl-Brouwer (2021) systemic problems (such as problems in the mental youth care sytem) are interrelated and can therefore not be solved independently. Therefore reseach was conducted in various contexts regarding the youth Mental Healthcare system:
1) The organisation involved with decisions regarding the youth care system. (Macro context)
2) The process of getting into care. (Meso context)
3) The interaction between youngsters and their therapists. (Micro context)
These analyses showed that youngsters often feel unheard and are not included in decision making. Therapists rely too much on their own vision and focus too little on background/individual factors of the youngsters. This leads to missing the core of the youngsters mental problems, which contributes greatly to ineffective and inefficient care. The analyses also showed that youth Mental Healthcare (j-GGZ) therapists are the most promising target audience to design for. In fact, other therapists - such as district members or therapists of the child and family centre (CJG) - often do not have the skills to find the core of the youngsters’ mental problems as they are often not specialized enough.
Following these analyses, the design goal has been to empower youngsters in decision making during GGZ therapy. A “Mijn Hulplijn” app was developed that helps youngsters to actually give feedback and incorporate it into therapy. The app allows youngsters to think of their own needs and wants in therapy, and helps to actually incorporate this as well. Moreover, it provides background information that is relevant for the therapist in question. Furthermore, the app offers suggestions for alternative therapies and gives an overview of the youngsters’ healthcare history. This way, the app can improve the success of the therapy and the youngster-therapist interaction. To actually make and measure this impact, this study also provided a plan for implementation of the app.","Social Design; Youth mental healthcare; Design","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:581b8540-d67b-42a0-94cc-0a2523cfd0a9","http://resolver.tudelft.nl/uuid:581b8540-d67b-42a0-94cc-0a2523cfd0a9","Aerodynamic Analysis of a Propeller-Powered Strut-Braced Wing","Beyne, Egon (TU Delft Aerospace Engineering)","Veldhuis, L.L.M. (mentor); Sinnige, T. (graduation committee); Delft University of Technology (degree granting institution)","2023","The aerodynamic performance of a regional, propeller-powered strut-braced wing is investigated. The main wing planform and operating conditions are based on an ATR72, to which a strut and jury strut are added. The research focuses on the different drag components in cruise. The first research objective is to quantify the effect the different wing components have on the change in induced drag caused by the propeller. The second objective deals with viscous effects, such as separation and friction. At the strut-wing and strut-jury strut junctions, it is tested whether the propeller affects the size and location of any separated regions. In addition, the influence of the propeller on the skin friction drag is quantified. The final objective deals with interference and compressibility. The close proximity of the strut, jury strut and wing, combined with the increased slipstream velocity of the propeller, and the change in angle of attack caused by swirl recovery might lead to high supervelocities. The regions with the highest supervelocities are localised, and it is verified whether any supersonic flow exists.
Induced drag is calculated with a panel method (Flightstream), which allows simulating different configurations in a relatively short time. By simulating different combinations of wing elements (with and without strut, jury strut and propeller) it is possible to isolate their contributions. The research objectives about viscous effects and interference were investigated using unsteady RANS. The CFD simulation were also used to validate the panel method. In general, it agreed well with CFD. Some discrepancies were caused by the absence of vortex dissipation and an offset in the pressure distribution inside the propeller slipstream.
The propeller reduced induced drag significantly, around 58% for all configurations. The main strut had the largest effect. Both the strut itself and interference of it with the wing lead to an additional reduction of 1% in induced drag. The jury strut had limited effect. Under the influence of a propeller, it had a small induced thrust component. Interference with the main wing cancelled out this benefit. These results were obtained using unoptimised loading distributions, optimising these would increase the gains for both the conventional and strut-braced wings.
The strut-wing junction only showed separation at the strut leading edge. The local flow behaviour was not influenced by the propeller. The strut-jury strut junction also exhibited leading edge separation, in addition to corner separation at the trailing edge of the jury strut, and separation at the trailing edge of the main strut. The size of the corner separation reduced under the influence of the propeller, by favorably changing the pressure gradient on the jury strut. The net effect of the propeller on the separated region at the trailing edge of the strut was to move it inboard, by increasing the pressure gradient there, and moving the location of the horse-shoe vortex system inward. Friction drag increased by roughly 3%, insignificant compared to the reduction in induced drag.
Finally, the region most sensitive to high supervelocities was the strut-jury strut junction. The closely spaced elements, combined with the higher slipstream velocity and increased angle of attack lead to a small supersonic pocket. Due to its limited size, it is expected that using a slightly different airfoil for the jury strut can already eliminate it.
While some attention needs to be payed to junction flows and interference effects, this work has shown the advantage of a propeller-powered strut-braced wing for regional aviation, compared to conventional aircraft.","CFD; Strut-Braced Wing; regional Aircraft; Propeller; Panel Method","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:1350ae04-b325-45cc-bb89-796a5e6059a8","http://resolver.tudelft.nl/uuid:1350ae04-b325-45cc-bb89-796a5e6059a8","Consensus-Based Auction Methods with Bid Intercession for SAR","Guillet, Victor (TU Delft Aerospace Engineering)","Sharpanskykh, Alexei (mentor); Lesire, Charles (mentor); Picard, Gauthier (mentor); Grand, Christophe (mentor); Delft University of Technology (degree granting institution)","2023","This research addresses the process of task allocation in a heterogeneous multi-agent fleet through the introduction of a novel mechanism in existing decentralised consensus algorithms: bid intercession. Bid intercession refers to the principle of agents biding on behalf of other agents in decision-making architectures leveraging market-based decision strategies. The method exploits and extends existing consensus-based allocation processes through the redistribution of responsibilities in the auction process to achieve various degrees of centralisation in the task allocation process. It is demonstrated that the extension proposed allows for hybridising multiple allocation methods together and structuring the auction process (notably through embedding hierarchies and decision trees directly in the decision-making process) all the while retaining the convergence robustness and performance guarantees provided by the underlying algorithms. The Search and Rescue case study is investigated to assist in framing the research and provide a reference scenario for the application of such concepts. This concept, unexplored so far in consensus-based approaches, not only opens up a sway of coordination architectures and optimisations but also paves the way to novel ethically compliant autonomous systems while retaining essential performance and robustness properties crucial in high-stake applications.","Task Allocation; Distributed Robot Systems; Multi-Robot Systems; Auctions; Consensus","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:99d7f2f4-93c1-47af-8b00-3d56122b64f3","http://resolver.tudelft.nl/uuid:99d7f2f4-93c1-47af-8b00-3d56122b64f3","Effect of Additive Manufacturing Scanning Strategy on the Crystallographic Texture of NiTi Shape Memory Alloys","Chatzopoulou, Chrysoula (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Materials Science and Engineering)","Popovich, V. (mentor); Zhu, Jia-Ning (mentor); Tang, Y. (graduation committee); Delft University of Technology (degree granting institution)","2023","Shape Memory Alloys (SMAs) are a class of metallic multi-functional materials which possess sensing and actuation capabilities, thanks to their unique ability to couple thermal and mechanical fields. NiTi-based Shape Memory Alloys exhibit properties which guarantee their high performance in adverse environments and, with the added benefit of two functionalities, the Shape Memory Effect and Superelasticity, these materials have become ideal candidates for a variety of applications. Spatial orientation of the NiTi crystals is crucial for achieving the superelastic functional response. According to studies on NiTi single crystals, when the grains adopt a [001] orientation along the direction of compression, slip is inhibited in the austenite phase and recoverable transformation strains similar to the theoretically estimated values of 5.3% are possible, defining the benchmark for superelastic responses. Additive Manufacturing techniques, due to their inherent thermal processing conditions, have created unprecedented opportunities for fabrication of NiTi-based Shape Memory Alloys so that the thermomechanical behaviour of the material can be tailored to any application is intended for. During Laser- Powder Bed Fusion, the scanning strategy influences the thermal processing to which the alloy is subjected, affecting its solidification process as well as the heat fluxes and temperature gradients that arise during manufacturing. Meanwhile, it can play a decisive role in achieving epitaxial solidification of columnar grains extending over multiple deposition layers. In this study, five different scanning strategies were employed during Laser-Powder Bed Fusion (L-PBF) of a Ni-rich NiTi alloy and were evaluated with respect to the grain morphology and crystallographic texture that developed, as well as the superelastic response of the samples produced. It was found that a 67° interlayer rotation of the scanning vector promotes the fusion of neighbouring melt pools, resulting in columnar grains that solidify epitaxially along the build direction (BD) of the sample. Meanwhile, a strong ⟨001⟩ fibre texture emerges along the BD. The superelastic response was stabilised at 4.5% recoverable strain with 74.2% recovery ratio after 16 cycles of axial compression loading. When an island scanning pattern was incorporated into the 67° rotation scanning strategy, the crystallographic texture strengthened and the superelastic response improved, (5.0% stabilised recoverable strain and 84% recovery ratio). Furthermore, an increase in the volumetric energy density, achieved by using a flat top laser beam, produced a nearly single-crystalline microstructure, with the highest intensity of the ⟨001⟩∥BD texture. The superelasticity in this case was stabilised at 5.5% recoverable strain with 91.5% recovery ratio. The effect of the loading direction on the superelastic response was also investigated, as was the nature of the residual strain left in the samples after their superelasticity stabilised. Therefore, this study successfully demonstrated that the scanning strategy can be a vital tool in designing the crystallographic texture and the grain morphology of NiTi parts fabricated by L-PBF, and this way, effectively tailor the superelastic functional behaviour to specific requirements of potential applications.","NiTi Shape Memory Alloys; Additive Manufacturing; Laser-Powder Bed Fusion; Crystallographic Texture; Scanning Strategy; Functional Properties; Superelasticity","en","master thesis","","","","","","","","2025-12-19","","","","Materials Science and Engineering","",""
"uuid:6ef24cf8-2dc5-4665-b581-a7c01a71f5dd","http://resolver.tudelft.nl/uuid:6ef24cf8-2dc5-4665-b581-a7c01a71f5dd","The effects of ionic strength and surface charge on O/W emulsion fouling of ceramic membranes quantified via DLVO and XDLVO models","Zhou, Hanxiao (TU Delft Civil Engineering & Geosciences)","Heijman, Sebastiaan (mentor); Chassagne, C. (graduation committee); Tanis, M.B. (graduation committee); Qin, G. (graduation committee); Delft University of Technology (degree granting institution)","2023","Large amounts of oily wastewater which included oil-in-water (O/W) emulsions, also known as produced water (PW), were produced in tandem with the enhanced oil recovery (EOR). Ultrafiltration (UF) was an effective and economic method to separate micron-sized O/W emulsions, while the membrane fouling limited its development. Understanding the fouling phenomena was essential to enhance the efficiency of membrane filtration for oil-water separation, hence this paper investigated the influence of different salinity (1 mM, 20 mM and 100 mM) and types of surfactants on the fouling of the alumina (Al2O3) membrane and the silicon carbide (SiC) deposited membrane filtrating 500 mg/L O/W emulsions with mean droplet sizes of approximately 4 ~ 7 μm, and the UF with the constant flux of 80 LMH and the crossflow velocity of 0.59 m/s was conducted. Sodium dodecyl sulfate (SDS, anionic), alkyl polyglycoside (APG, nonionic), and cetyltrimethylammonium bromide (CTAB, cationic) were chosen in this study due to the frequent use in EOR, and the N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (DDAPS, zwitterionic) was selected because of its low tendency to foul at high salt concentrations.
Derjaguin-Landau-Verwey-Overbeek (DLVO) and the extended DLVO (XDLVO) models were used to quantify the membrane-oil droplet and deposited oil layer-oil droplet surface interaction. The results showed that the SiC-deposited membrane had less membrane fouling and irreversible fouling resistance compared with the Al2O3 membrane when filtrating O/W emulsions stabilized with SDS, APG or DDAPS. The DLVO model estimated emulsion fouling propensity to rise with increasing salinity when dealing with SDS, APG or DDAPS-stabilized O/W emulsions, while CTAB-stabilized emulsion fouling propensity for the SiC-deposited membrane would decrease with the higher salinity.
How can different stakeholders regarding the sustainable transition of the maritime industry be assessed using the discourses of Dryzek?
With a basis of Q-methodology, a list of statements was created that, based on Dryzek’s discourse theory, is then used to judge the respondents on their environmental beliefs. Also the sustainability reports of selected companies where investigated. It was possible to identify the main themes that could count on agreement/disagreement and controversy. Nature and the existence of limits to our activities where rated highly, while the way to solve it remained controversial. People are more imaginative than their company’s current policies indicate. People see the limitations to the systems that surround them. The willingness of the employees is there, or there is a lack between the strategy of the board and the values of the employees. Further action is required to bridge the gap.
It is indeed possible to asses different stakeholders and firms on their discourses and the research shows two methods to do it. The set up of the interview and the statements proved to be able to provide information about the environmentalism of the stakeholder. This information gives an insight into the social context of environmentalism and brought forward interesting observations about the willingness of the employees and the stance of the companies. The reports indicate a gap between what is needed (and wanted) and what is currently being done. The companies should be more radical and imaginative in both their vision and their solutions, instead of focussing on the solutions alone. Vision is often omitted from the reports, an important oversight.
Overarching vision and motivation can be uncovered but the specific points of departure for technological advancement remain hidden. The thesis brings a contribution to investigations on stakeholder alignment in the clean shipping sector and uncovers some important issues. The firms specific operating context remains to be investigated with more detail, as to properly find the barriers that hold back solving wicked problems. However a good effort is made to indicate the grounds for disputes from the actors.
measured with EDS. XRD analysis shows that the compressive residual stress from shot-peening is 1.5 times higher and twice as deep in Gasloos compared to Reference. This is due to the oxide scales, containing 17.49 weight% oxygen, that comprise the surface of Reference, making it very brittle and filled with voids. Gasloos does not have these oxide scales at the surface.","Steel; Martensite; Embrittlement; Grain boundary segregation; Tempering","en","master thesis","","","","","","","","","","","","Materials Science and Engineering","",""
"uuid:6920a433-459f-4435-a2bb-19c523baad4c","http://resolver.tudelft.nl/uuid:6920a433-459f-4435-a2bb-19c523baad4c","Environmental Analysis of End-of-Life Scenarios for Decommissioned Crystalline Silicon PV Modules","Drop, Kevin (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Photovoltaic Materials and Devices)","Vogt, M.R. (mentor); Weeber, A.W. (graduation committee); Vahedi, H (graduation committee); Eijsbouts, René (mentor); Delft University of Technology (degree granting institution)","2023","Many functional photovoltaic (PV) modules are decommissioned prematurely, often due to the financially motivated repowering of PV systems. This study assesses under which circumstances there is an environmental incentive to reuse these modules as opposed to recycling and replacing them with new, more efficient modules. A life cycle assessment was conducted, covering the end-of-life treatment, manufacturing, transport and use phase of decommissioned and new modules. The decommissioned modules had an efficiency of 14.7% in 2011, the new modules have an efficiency of 19.79%. The analysis covers two different reuse scenarios (local and export) and two different replacement scenarios, based on the quality of the recycling and the manufacturing country of the new modules.
The impacts are quantified in three categories: global warming potential, eco-cost of resource scarcity and total eco-cost. The findings indicate that, because of rapid technological advancements, the recycling and replacement of 10-year old decommissioned modules generally yield greater environmental benefits than local reuse: the net benefit in terms of global warming is greater after only 5 years. In addition, the calculations show that reusing decommissioned modules in a new PV system is only the preferred strategy from a global warming perspective if the modules are less than 5 years old, if that system is intended to have a (financial) lifetime of 10 years or longer.
However, reuse in a selected European Union member state can provide greater benefits in the global warming potential and total eco-cost impact categories than recycling and replacement. The advantage of export is driven by higher annual irradiation as well as a higher emissions intensity of the electricity mix.
These results contrast the conventional belief that reuse is always environmentally preferable to recycling. Based on this research it can be argued that in most cases of premature decommissioning, there is no strong environmental incentive to reuse the modules, provided that new PV modules are widely available or that the materials go directly to the production of new modules. The annual efficiency increase of PV technology was identified as a key parameter for this outcome.","PV panels; Life cycle assessment (LCA); Reuse","en","master thesis","","","","","","","","","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:e5654c1a-7eeb-4133-9419-065fe04349f1","http://resolver.tudelft.nl/uuid:e5654c1a-7eeb-4133-9419-065fe04349f1","Exploring the acceptance of innovation based on standardization in a construction programme: The role of uniqueness bias in the acceptance of innovation","Putu Gandhi Padma, Padma (TU Delft Civil Engineering & Geosciences)","Molaei, M. (mentor); Elmohr, S.E.M.A. (graduation committee); Delft University of Technology (degree granting institution)","2023","This thesis investigates the role of uniqueness bias in the acceptance of innovation based on standardization within construction programs, using the Programma Bruggen en Kademuren (PBK) as a case study. The research aims to bridge the gap in the literature regarding uniqueness bias and the acceptance of standardized innovation in the construction industry. Initially, a literature review was conducted, leading to the formulation of two hypotheses. These hypotheses were tested through semi-structured interviews, after gaining insights into the innovation acceptance process within the programme. This involved both document reviews and exploratory interviews with individuals involved in the development of innovation in PBK. The findings reveal that PBK fosters innovation through internal development and external innovation partnerships. This information guided the creation of criteria and questions for the semi-structured interviews. The interviews were analysed using thematic analysis, revealing factors that influence the acceptance of standardized innovation, categorized into preconditions, barriers, and enablers. Specifically, three preconditions, eight barriers, and two enablers were identified. Upon comparing the interview results with the initial hypotheses, no supporting evidence was found for either hypothesis. The identified factors were then used to develop three intervention plans aimed at enhancing innovation acceptance within a programme. These interventions include establishing a clear baseline direction, creating an Innovation section within the programme forum, and implementing contractual flexibility for innovation integration. Each intervention plan is designed to address identified barriers and enhance enablers, thereby fostering an optimal environment for innovation acceptance in public construction programmes","innovation acceptance; construction programme; uniqueness bias","en","master thesis","","","","","","","","2025-12-12","","","","Civil Engineering | Construction Management and Engineering","Programma Bruggen en Kademuren",""
"uuid:8379608c-e790-45cb-918c-c93cead6fb3a","http://resolver.tudelft.nl/uuid:8379608c-e790-45cb-918c-c93cead6fb3a","Serviceability of a Cantilever Grandstand under Dynamic Crowd Loading","Knibbe, Jelle (TU Delft Civil Engineering & Geosciences)","Lourens, E. (graduation committee); van der Meer, F.P. (graduation committee); Steenbergen, Raphael D.J.M. (mentor); de Vries, Rein (graduation committee); Delft University of Technology (degree granting institution)","2023","This thesis presents a novel methodology to determine the reliability of cantilever grandstands under dynamic crowd loading. No method currently exists to evaluate this, despite the occurrence of significant vibrations in such structures, for example in the Feyenoord Stadium in Rotterdam. These vibrations can negatively affect both the safety and serviceability of such structures, so a method able to evaluate both is desirable. The methodology consists of four components: a model of a grandstand, a model of the dynamic crowd load, a failure criterion, and a reliability analysis. Of these, the first and third component are case-specific, as a wide range of different grandstands and different criteria could be considered. In this thesis, the methodology is applied on a case study based on the Feyenoord Stadium, with a model of the trusses beneath the main grandstand of this stadium, and a criterion based on the intensity of the vibrations of the upper cantilever of this grandstand, a serviceability issue. The second component represents the most novel aspect of the methodology: a model describing the dynamic crowd load, defined in the frequency domain, and generally applicable regardless of the structure being considered. The core of this model is a parameterisation of the amplitude spectrum of the load applied by a group of jumping spectators. The parameters describing the spectrum are considered as stochastic variables, with distributions fitted using samples from a state-of-the-art database of measured loads. As opposed to the first and third components, this load model should be generally applicable.The parameters of the load model, together with other stochastic variables in the grandstand model, form the input of a Limit State Function. The output of this function determines whether the structure loaded by the crowd meets a certain criterion, and forms the basis of a reliability analysis together with the distribution of the stochastic variables. The probability of \emph{not} meeting the criterion, the failure probability, is calculated through a number of reliability methods in the final component of the methodology. These methods should be generally applicable as well, though which methods fits the best could still depend on the case being considered. This methodology was successfully applied on the case study, and a failure probability was found with two different methods. One of these, Crude Monte Carlo, allowed for a more fluid view of the concept of `failure' when a serviceability criterion based on a subjective limit is considered. The other method, SDARS, returned a slightly larger failure probability, in a much shorter runtime than Monte Carlo. This method is therefore more fit for safety criteria with a small (expected) failure probability, for which Monte Carlo would require an unreasonably long runtime. In addition, the wider applicability of the methodology has been investigated. An important requirement for this is flexibility with regards to the applied reliability methods. Two other methods, Directional Sampling and SDARS, were also attempted but did not yield usable results. This is caused by the manner in which phase angles are defined in the frequency-domain model. Random values are drawn, which causes noise to appear in the limit state function: a constant input does not lead to a constant output. Being able to use different reliability methods is an important requirement for applying the methodology in a wider variety of cases. In order to apply these methods, the phase angles need to be defined in a manner which does not introduce noise. Another important requirement is the ability to consider different failure criteria. While the criterion applied in the case study could be evaluated in the frequency domain, many others will require the results to be transformed to the time domain. Applying this transformation to the frequency-domain results of the models currently does not yield usable results, which is likely also caused by the definition of the phase angles in the load. In conclusion, while the methodology is applicable on the case study, the definition of the phase angles requires attention before it can be applied on other cases.","Reliability; Structural Dynamics; Crowd Loads; Finite Element Model; Serviceability","en","master thesis","","","","","","","","","","","","Civil Engineering","","51.8939035, 4.5231354"
"uuid:2909d997-a983-490a-a588-87119998543a","http://resolver.tudelft.nl/uuid:2909d997-a983-490a-a588-87119998543a","On Forecasting the Rur River: Using hindcasts and forecasts of the 2021 flood event to improve understanding of flood forecasting in the Rur catchment","Hartgring, Sebastian (TU Delft Civil Engineering & Geosciences)","Ragno, E. (mentor); Uijlenhoet, R. (mentor); Mosselman, E. (mentor); Hegnauer, Mark (mentor); Bachmann, Daniel (mentor); Delft University of Technology (degree granting institution)","2023","The Netherlands, Germany, and Belgium were hit by heavy and prolonged precipitation in July 2021. As time passed, weather warnings escalated, leading to evacuations due to predicted floods, including in the Rur catchment. It was difficult to forecast the flooding of the Rur, raising the question of which elements are crucial in a flood predictionmodel for the Rur river. This question is addressed by addressing both a hindcast of the 2021 flood event and creating forecasts based on the weather forecast of July 13, 2021.
The Rur river basin is characterised by topographic and geological variations, with the steep Eifel responding differently than the flat lowlands, and human intervention in the form of reservoirs and lignite mines. A hydrological Wflow_SBM model has been derived for the Rur river basin, encompassing these characteristics, along with a hydrodynamic ProMaIDes model for the downstream reach of the Rur. These models were compared to investigate various aspects: river routing, floodplain flow, tirbutary interactions, the influence of reservoirs, and the impact of reduced groundwater levels.
The results of the 2021 floods indicate that modelling flows in floodplains is crucial to shaping the flood wave, both in tributaries and the Rur itself. Additionally, the reservoir played a significant role in attenuating the flood wave, with the increase in the outflow of the reservoir primarily affecting the tail of the wave. The reduced groundwater level was simulated by adding a leakage termto the saturated subsurface zone, whose indirect effect is significantly greater than the leakage termitself. Moreover, the tributaries Worm and Inde, particularly, are influential in the Rur’s discharge. These characteristics are also evident in the simulated forecasts, although the spatial and temporal resolution is significantly lower for these meteorological predictions.
Finally, the characteristic response of the Rur demonstrates that not everymodel type is equally practical for flood forecasting. The dominant flow from the reservoirs is highly regulated and is unlikely to induce inundations downstream. Complex flow patterns in floodplains only become relevant in the Dutch Rur, which makes two-dimensional modelling particularly valuable here. Therefore, it is recommended to use a one-dimensional discharge model, incorporating delay effects from winter bed flows. When predicted discharges at the Stah station are exceeded, two-dimensional simulations may provide a solution, the model area reduced to the Dutch Rur, focussing on predictions where a critical value related to floodplain capacity (Qlimit = 300 m^3/s) is exceeded.","flood forecasting; Rur river; Rur reservoir; 2021 flood event; ProMaIDes; Wflow; lignite mining","en","master thesis","","","","","","","","","","","","Civil Engineering | Hydraulic Engineering","","50.6369, 6.4424"
"uuid:5b4d24ef-a2d5-44a4-88c8-dc90d9b3b559","http://resolver.tudelft.nl/uuid:5b4d24ef-a2d5-44a4-88c8-dc90d9b3b559","Acoustic Materials for Wearable Ultrasound patches: Developing an ultrasound skin mimicking phantom","Boertje, Puck (TU Delft Mechanical, Maritime and Materials Engineering)","Dekker, R. (mentor); Kawasaki, S. (graduation committee); Delft University of Technology (degree granting institution)","2023","With today’s aging population and the prevalence of chronic illnesses, healthcare systems worldwide are struggling to accommodate the increasing number of patients. This projected growth and rising demand underscore the importance of advancing wearable devices. In the realm of diagnostic healthcare, the pursuit of non-invasive and safe techniques is paramount. Until now, body patches have predominantly focused on monitoring surface-level body parameters such as temperature, humidity, pH, oxygen saturation, and electric potentials. The introduction of ultrasound patches extends the realm of possibilities, enabling a deeper exploration of physiological processes within the body. Additionally, ultrasound serves as a non-invasive diagnostic technique. To facilitate medical ultrasound imaging, an acoustic interface is indispensable for the unimpeded transmission of waves through the skin and tissue. This interface must maintain proper hydration and adhere to the skin to ensure a conforming acoustic connection. Initially, this MSc. thesis research aimed to conduct lifetime performance tests on promising ultrasound acoustic interface materials. These tests were conducted by placing wearable ultrasound patches with the acoustic interface materials in place on an ultrasound phantom. With the ultrasound transducer, ultrasound images were made over a fixed period. This experiment was done to see to which extent the image quality would degrade over time for the different interface materials. The available ultrasound phantoms did not meet the requirements of skin-mimicking properties, on which the lifetime of the acoustic materials would be tested. Consequently, this research opted to simulate specific skin conditions: temperature, moisture, and acoustic properties like human tissue. Different iterations were made and evaluated during the development of the final ultrasound phantom model. In this thesis, five different models were evaluated, and eventually, the final model was presented: A three-layer model. The phantom model consists of a gel wax filled with scattering objects, visible with ultrasound, at specific depths inside the filling. To mimic the water loss rate of the skin, a hydrating layer of agar was placed on top of the gel wax filling. A PET foil was deployed with a specific number of holes to let water through from the agar layer to regulate the amount of water evaporation over time. To mimic skin temperature, the phantom model was placed in an oven at T = 34 °C. With this final model, the lifetime experiments were conducted with six potential interface materials: AquaFlex (solid hydrogel), HydroAid (solid hydrogel), Ecoflex (silicone), Axelgaard (ECG solid hydrogel), HH5023 (ECG solid hydrogel), and HH5450 (ECG solid hydrogel). The duration of this experiment was eight days, after which the agar layer started to degrade and shrink. The filling and scattering objects of the phantom model are reusable, while the hydration layer has to be replaced or disposed of after five days. Further, acoustic properties, like materials-specific attenuation coefficient, of potential acoustic interface materials and materials used in the phantom were measured using a though-transmission setup. Also, a validation assessment of skin compatibility of the potential interface materials for a long duration of time was conducted. This was done with the consultation of experts in medical devices, medical professionals and literature. With these three different subjects of this MSc. the attenuation coefficient of six different acoustic interface materials are characterized and validated to be compatible with human skin for longer periods. The phantom model developed satisfies the requirements set and, most importantly, mimics skin temperature and water loss rate. One round lifetime (eight days) performance experiments of acoustic interface materials using the phantom model. It is difficult to conclude to which extend the image quality degraded over time for the different interface materials due to the agar layer dehydration after eight days and that the experiment was only conducted once. For future recommendations, it is suggested that the lifetime experiments be repeated using the phantom model for these six different interface materials. It could also be an option to renew the hydration layer every seven days to prevent the agar layer from dehydrating over the acceptable limit if the experiment requires longer periods.","wearable; ultrasound; phantom; skin-mimicing; acoustic materials; interface; acoustic attenuation; skin compatibility","en","master thesis","","","","","","","","2024-12-20","","","","Biomedical Engineering","",""
"uuid:9eabd441-20f0-4071-953e-771bf440d12a","http://resolver.tudelft.nl/uuid:9eabd441-20f0-4071-953e-771bf440d12a","Multi-Agent Task Allocation and Path Planning for Autonomous Ground Support Equipment: Master of Science Thesis","van der Zwan, Manouk (TU Delft Aerospace Engineering)","Sharpanskykh, Alexei (mentor); Ermis, G. (graduation committee); Delft University of Technology (degree granting institution)","2023","Many large airports aim to have complete autonomous airside operations in the future. Amsterdam Airport Schiphol (AAS) for example, launched the Autonomous Airside Operations program to achieve this goal. Our main contribution is to present a Multi-agent Pickup-and-Delivery (MAPD) model that uses a centralized task allocation mechanism to improve the performance of integrated task allocation and path planning for autonomous ground handling operations compared to previous research. This study models a global multi-vehicle Pickup and Delivery Problem with Time Windows (PDPTW) for the scheduling of autonomous ground handling tasks. A warm start multi-objective mixed integer linear programming model is proposed to solve the scheduling problem where the initial feasible solution is obtained by an insertion heuristic. This multi-agent task allocation model, when combined with multi-agent path planning, forms a MAPD model for modeling autonomous ground handling operations. Multi-agent path planning is solved using prioritized Safe Interval Path Planning (SIPP). A replanning model is developed to assess the resilience of our model to disruptions of operations. Also, a mixed integer nonlinear programming model, which includes an additional non-linear objective, is proposed to generate more realistic task assignments by minimizing the waiting time of vehicles on the aircraft stands. In this study, a four-hour planning window with three aircraft stands at AAS is used for the experiments. The results show that the proposed approach improves the computational time of the task allocation model with 48% for the normal traffic scenario, compared to the previously published results. The conflict-free routes of all ground support equipment (GSE) vehicles are all successful and close to the shortest path results, with an average increase of 0.04% and 10% for the path length and the duration of the path, respectively. Our model is therefore able to generate complete, high quality solutions in less than three minutes.
The matchmaking system is defined as the framework that ensures matchmaking, which uses a ""key"" generated by the sender to represent the return package. If the receiver can find the key upon arrival of the return package at the depot, the sender can be identified. Seven matchmaking systems were considered. Five alternatives use unique tray identities as key. One alternative uses the load carrier as key and the last alternative uses the return package identity as key. The validation results show that an ""all read"" or ""reading of all individual trays"" is not a requisite for a working matchmaking system. By contrast, as long as a certain ratio of reading at two locations is reached, an all-read scenario can be mimicked. The assessment investigated the instances in which zero mismatch take place. Results show that the higher the data capture capability of both the sender and receiver, the higher the chance a match can take place and the smaller the chance of a mismatch. This thesis creates insights on requirements for enhancing traceability of RTI's in the return chain and developed a matchmaking concept that can address the practical problem of returns without traceability of shop origin. The developed matchmaking concept is the outcome of an analysis of the current state and makes use of data elements that are already being collected in the database, in the case of EPS. The study addresses how collected data can be leveraged for enhanced RTI management in the reverse logistics and may inspire practitioners to face challenges with a similar lean approach.","Returnable Transport Items; Returnable packaging; Reverse Logistics; Traceability; Asset Management; Design Science; Deposit System","en","master thesis","","","","","","","","2025-12-19","","","","Transport, Infrastructure and Logistics","",""
"uuid:186414f8-e034-47f8-99b4-81eba0231577","http://resolver.tudelft.nl/uuid:186414f8-e034-47f8-99b4-81eba0231577","Measuring the social impact of social enterprises on SDG3: An analysis of the perspectives of funders and social enterprises","Huizing, Zoé (TU Delft Technology, Policy and Management)","Hinrichs-Krapels, S. (mentor); Verbraeck, A. (mentor); Gammon, A.R. (mentor); van Smeden, G. (graduation committee); Delft University of Technology (degree granting institution)","2023","Social enterprises play a significant role in achieving the Sustainable Development Goals (SDGs). Measuring the social impact of social enterprises presents several challenges, including the complexity of social issues, the need for standardized metrics, and the limited resources available. Obtaining funding is crucial for social enterprises to fulfill their mission. When applying for funding, they often have to report on the social impact they generate, as it is an essential part of the value they create. Another difficulty is that social impact is experienced differently by various actors. The research, therefore, adopts an exploratory approach to understand how funders and social enterprises perceive the impact assessment, particularly for those contributing to SDG 3. Thus, the central question of this research is 'How are funders and social enterprises aligned in measuring social impact on SDG3?'.
This research was conducted in partnership with Unifix Care. Unifix Care is a social enterprise whose mission is to improve access to safe surgical care in Sub-Saharan Africa. The findings presented were derived from a review of the literature, interview rounds, and a survey. The first round of interviews were exploratory interviews with general impact funders. The second round consisted of interviews with social enterprises contributing to SDG and funders funding these social enterprises. The survey aimed to validate statements based on literature and interviews and to give an idea of the data funders and social enterprises use some impact indicators.
A finding of this research is that the change in how the Theory of Change is used, from an internal tool to an external accountability mechanism, indicates a misalignment between funders and social enterprises. While funders may demand accountability, social enterprises initially used it for internal improvement. This shift suggests a divergence in how both parties perceive and utilize this tool for measuring social impact. Social enterprises' power imbalance and dependency on funders can lead to a misalignment in measuring social impact. Contributing to this is the fact that aligning the mission of social enterprises with the strategic goals of funders is considered very important.
A subsequent finding is that there could be a reporting difference between easier-to-measure KPIs from the Theory of Change (input, activity, output) and harder-to-measure KPIs more aligned with the overall goal (outcome and impact). The survey results indicated a mild divergence in opinions between funders and social enterprises on the priority of measuring input, activity, and output indicators versus outcome and impact indicators. Social enterprises were somewhat in favor, whereas funders were somewhat opposed. In terms of quantifying outcome and impact indicators, a simple, state-of-the-art calculation was generally adequate for most social enterprises, in contrast to the preferences of funders. These findings could result in the miscalculation of social impact generated by social enterprises. For this, it is necessary to bring back the Theory of Change as an integrated framework.
Another finding is that both social enterprises and funders focus more on a social enterprise's positive rather than negative impacts. Given that every social enterprise likely has some adverse effects, these should be acknowledged to ensure a comprehensive assessment of the overall positive social impact. Additionally, it is found that the inconsistency in defining 'impact investors' and the varied interpretation of 'impact first' approaches reflect a lack of uniformity in how social impact is perceived and measured. This variability can lead to challenges in aligning the measurement approaches of funders and social enterprises.
The main limitations of this study are related to the small survey sample size, which only provides an indication. More research is needed to draw definitive conclusions. Another limitation is the selection and categorization of indicators in the survey; an attempt was made to do this as generically as possible. However, future research would benefit from validating this selection and categorization by multiple experts.
The following recommendations aim to foster effective collaborations between funders and social enterprises, enhancing transparency and accountability in social impact measurement. A publicly accessible database should be created to share the social impact results of social enterprises. This will allow for establishing normal distributions and facilitate the assessment of the likelihood of success of similar interventions. Therefore, a portion of funding should be dedicated to monitoring the long-term impact of social enterprises. This enhances transparency and allows for a deeper understanding of the effectiveness of various investments in achieving social impact. Funders should also publicize the Theories of Change of the social enterprises in their portfolio. This transparency helps understand how the impact is achieved and mitigates the risk of 'impact washing.' The initiative for these recommendations, particularly the database and publication of Theories of Change, should come from the government or the actors funding the funders. They have the influence to drive more impact-focused decisions and support impact-driven social enterprises. Future studies should incorporate comparative cognitive mapping and game theory to understand better the preferences and incentives of funders and social enterprises. Additionally, using Agent-Based Modelling or System Dynamics with the EMA workbench could yield insights into the effectiveness of specific policies in a complex, uncertain environment.
Recently, the importance of developing spatial thinking has been recognized with the European Union stimulating its development at an early age. Many studies of ways to foster spatial thinking of young children, through online activities as well as embodied activities, have been conducted and provide valuable insights that can be used in preschool settings. In design and engineering, spatial thinking is required to imagine and visualize novel and creative solutions and products. However, design play in preschools has not been researched in the context of spatial thinking so far. Next to this, little is known on individual differences in the way preschools use and develop spatial thinking skills in early childhood. Therefore, in collaboration with Sciencehub TU Delft the aim of this project was to:
-Gain insight into diversity of learners and the way they engage and interact with design activities in a classroom context.
-Develop educational innovations which take the diversity of learners into account, and stimulate spatial learning in the context of Design and Technology Education.
-Develop a tool for educational professionals which communicates the findings of this project.
Methodologies employed
Throughout the project the following methodologies were employed:
Literature research exploring spatial ability in the context of preschoolers, education, design and play.
-Participatory qualitative interviews and observations with preschoolers in their classrooms to explore different play preferences.
-Generative design research methods grounded in ethnographic research and therapeutic practices to discover how preschoolers with different play preferences interact with an empathic, story-based open-ended design challenge.
-Focus group with preservice teachers to explore how they currently take the diversity of learners into account.
-User tests with preschoolers and teachers to test and improve the proposed design interventions.
Research outcomes
Exploring the context of preschooler and teachers resulted in the following summarised research outcomes:
-Important play preferences for preschoolers are: construction play, pretend play, open-ended objects, and defined objects.
-The play preferences of children influence the length and nature of design activities as well as the design outcomes.
-Design activities stimulate children to practice spatial thinking in a creative context.
-Teachers know a lot about their students, so the intervention should allow them to use this knowledge.
Intervention – preschoolers
Based on the research outcomes two variations of assignments, which have the same learning goal, were designed. Each variation focused on a different set of preferences, allowing the preschoolers to interact with the assignment that fits their preferences best.
Intervention – teachers
A booklet summarising the outcomes of this project was made. An actionable step-by-step plan and worksheet were created with which teachers can design their own variations of assignments based on preferences of students in their class.
The interventions were evaluated with preschoolers and (preservice) teachers, and showed promising results. Recommendations regarding improvements and implementation are provided.
Thirteen Dutch military helicopter pilots flew scenarios with six different SD events using an AH-64 Apache flight model in virtual reality in a 6-DoF motion simulator. The SD events used were: “False Horizon”, “Featureless Terrain”, “the Leans”, “Brownout”, “Somatogyral Illusion” and “Night Vision Goggles (NVGs)”. Corresponding scenarios without the SD events were performed to obtain baseline measures of cognitive performance. When performing the scenarios, participants had either the role of pilot flying or pilot monitoring.
To test the cognitive performance, participants performed a mathematical processing task. The corrected reaction time and error rate were significantly higher during the SD events than during the baseline events.
These effects were most prominent in the “Featureless Terrain” and “the Leans” scenarios. The results indicate that SD has a negative impact on the cognitive performance of military helicopter pilots. These findings underline the importance of SD awareness training for pilots, as well as the use of workload management procedures when experiencing SD.","Spatial Disorientation; Cognition","en","master thesis","","","","","","","","2025-12-04","","","","Aerospace Engineering","",""
"uuid:e718cc72-c4e7-45f7-89c4-dd0bda7e79b0","http://resolver.tudelft.nl/uuid:e718cc72-c4e7-45f7-89c4-dd0bda7e79b0","Language Assistance in Reinforcement Learning in Dynamic Environments","van Leeuwen, Sander (TU Delft Electrical Engineering, Mathematics and Computer Science)","Spaan, M.T.J. (mentor); Bohmer, Wendelin (graduation committee); de Vries, J.A. (mentor); Yang, J. (graduation committee); Delft University of Technology (degree granting institution)","2023","Language is an intuitive and effective way for humans to communicate. Large Language Models (LLMs) can interpret and respond well to language. However, their use in deep reinforcement learning is limited as they are sample inefficient. State-of-the-art deep reinforcement learning algorithms are more sample efficient but cannot understand language well. This research aims to study whether RL agents can improve learning by utilizing language assistance and how LLMs can help them. A sentence describing the agent's environment is fed into an LLM to create a semantic embedding, which is consumed by a recurrent Soft Actor-Critic (SAC) agent to create an agent that can listen to natural language. This research shows that the best method for the agent to consume the embedding is concatenating it to each observation. Also, LLM-based embeddings lead to faster and more stable learning than non-LLM-based embeddings. The agent is sensitive to noise in the embedding but not to the embedding's dimensionality. The agent can generalize well across sentences that have a similar meaning to sentences seen during training but are formulated differently, but it can not generalize as well across sentences with unknown subjects and needs the subjects of the sentences to be grounded in training. Lastly, this research shows that the proposed architecture supports scaling language assistance to more complex environments.","Reinforcement Learning; Soft Actor-Critic (SAC); language assistance; Large Language Models (LLMs); GPT-4; semantic embedding; transfer learning; meta-learning","en","master thesis","","","","","","Source code and datasets can be found here: https://doi.org/10.5281/zenodo.10322510","","","","","","Computer Science","",""
"uuid:0d6e7834-83d6-49ab-a5b3-e3d5fd9a7612","http://resolver.tudelft.nl/uuid:0d6e7834-83d6-49ab-a5b3-e3d5fd9a7612","Active Mechanical Metamaterial for Tunable Vibration Isolation","Schouten, Koen (TU Delft Mechanical, Maritime and Materials Engineering)","Hunt, A. (mentor); Delft University of Technology (degree granting institution)","2023","Materials and material structures with highly specialised and unique mechanical properties are sought after in order to gain the most performance from a system. Materials generally have fixed mechanical properties and are unable to adapt in the case of new or unforeseen situations. Active mechanical metamaterials are able to alter the fundamental mechanical properties in real-time.
The literature review looks at the state of the art active mechanical metamaterials from the perspective of their control strategies and actuation principles. This is done to get a better view of what materials are out there, what applications are suitable for specific active mechanical metamaterials and what gaps can be explored in the future.
The literature review found that the active mechanical metamaterials can be classified by type of control into closed loop and open loop control, as well as the location of actuation into locally actuated and globally actuated materials. Furthermore, the active mechanical metamaterials are highly specialised for their respective applications.
Controlling the active mechanical metamaterials effectively, especially with a large amount in unit cells is the main challenge for most of the active mechanical metamaterials. For this propose, globally actuated and open loop control principles provide the best opportunities for simple, large scale controllable active mechanical metamaterials, though the actuation domains used for the globally actuated active mechanical metamaterials is less precise than the domains used in the closed loop active mechanical metamaterials.
The main report proposes an approach to place and manipulate the band gaps in local resonance mechanical metamaterials via open loop actuation. The state of the art local resonance mechanical metamaterials are lacking in tunability of the band gaps, even though the ability to change the location of these band gaps is very desirable to alter the dynamics of the system.
The design concept is based on the working principle of a local resonance mechanical metamaterial and incorporates a method for tuning the resonator stiffnesses. The tunable stiffness is achieved through the straining of opposing flexures, which are actuated by externally applying a strain to the unit cell through the use of chevron motion amplifiers.
The fabricated prototype showed comparable stiffnesses to the stiffnesses obtained using the FEM analysis, and showed an increase of the resonator stiffness from 1530 N/m to 3290 N/m. Furthermore, the prototype showed a change in band gap from between 73 Hz and 86 Hz to between 78 Hz and 92 Hz in response to the application of lattice pre-strain of 0.50mm. This mechanical metamaterial is therefore successful in the tuning of antiresonances in local resonance mechanical metamaterials through externally applying a strain to the metamaterial. In the future, mechanical metamaterials with this tunable band gap behaviour can be useful for applications where a lightweight, open loop, tunable vibration isolation approach is required.","Active Mechanical Metamaterial; Antiresonance; Dynamic Metamaterial; Vibration Isolation","en","master thesis","","","","","","","","2025-12-18","","","","Mechanical Engineering | Mechatronic System Design (MSD)","",""
"uuid:88047508-796b-44b6-b8dc-962c164bb761","http://resolver.tudelft.nl/uuid:88047508-796b-44b6-b8dc-962c164bb761","How Do Exoskeletons Change Shoulder Biomechanics?: A New Design Tool for “Human-In-the-Loop” Optimization of Shoulder Exoskeletons","ZHOU, SIYANG (TU Delft Mechanical, Maritime and Materials Engineering)","Seth, A. (mentor); Radaelli, G. (mentor); Nejadseyfi, O. (graduation committee); Delft University of Technology (degree granting institution)","2023","Shoulder exoskeleton is a popular solution to work-related shoulder disorders and muscle fatigue. With a wide range of exoskeletons designed, a comprehensive report on how the use of shoulder exoskeletons changes shoulder biomechanics is still missing. In this project, the impact of exoskeletons on shoulder biomechanics was investigated with the musculoskeletal simulation OpenSim. This study proposed a ""human-in-the-loop"" optimization-based design tool for shoulder exoskeletons. This design tool incorporates the predicted biomechanical effects of a shoulder exoskeleton from musculoskeletal simulations into design considerations. This design tool was validated with a case study designing a shoulder exoskeleton based on a compliant beam and testing the design in the musculoskeletal simulation and experiments.
The exoskeleton design tool is a coupling of finite element analysis and OpenSim. OpenSim calculates the deformation of the exoskeleton with human motion, and the finite element analysis calculates the force exerted from the exoskeleton upon deformation. Then OpenSim computes muscle activities under the external force from the exoskeleton. By merging muscle activities and the resultant glenohumeral joint reaction force to an objective function, the optimization-based design loop is closed by looking for the best objective value iteratively.
Several exoskeletons were designed by the new design tool to assist different types of tasks. The design tool exhibited good ability in finding optimal solutions for a range of design choices and design requirements. Simulated tests of designed exoskeletons showed significant effects on reducing muscle activities and good robustness in resisting the influence of perturbed motions in arm-elevated tasks. An exoskeleton was selected to be tested with an experiment set up in the same way as the simulated test. Experiment results supported the performance of the exoskeleton predicted in the simulated test.
This project established a method to comprehensively predict the effect of an exoskeleton on shoulder biomechanics and provided a more comprehensive understanding of biomechanical effects of shoulder exoskeletons. This facilitated the “human-in-the-loop” design process of shoulder exoskeletons which could greatly save money and time investments into prototyping, testing, and validation.
The TSP is a cornerstone in combinatorial optimisation. Specifically, for this research, TSP serves as a means of understanding the challenges and intricacies of inland waterway networks. Employing the GNN model, the research provides insights into potential solutions for TSP within this context. When comparing various TSPLIB instances, the GNN model showcases its efficiency and potential for further refinement, especially in real-world routing and logistics.
Shifting the focus towards production planning, the JSSP emerges as a pivotal problem. It aims to optimise the order and timing of tasks for various ships, ensuring minimal usage of time and resources. By implementing the GNN architecture, the research offers a fresh perspective on JSSP. When applied to real-world scenarios, it is evident that the model can predict optimal scheduling sequences, matching the actual time frames and resource allocation required, thereby promising significant advancements in maritime trade efficiency.
Diving deeper into operations research, the RCPSP surfaces as a challenge that focuses on optimising project schedules, considering resource constraints and task precedents. The research introduces an approach to address this problem, especially concerning cargo operations within port networks. The research promises efficiency, reliability, and adaptability in Inland Waterway Transport (IWT) scheduling practices by integrating renewable resources and managing precedence relationships.
Lastly, the WSSP centres on managing ship movements within a defined time frame, optimising the sequence and timing of vessels to minimise delays and maximise the utilisation of waterway infrastructure and resources. Building upon the foundational work of previous research, this problem was translated and redefined in the context of the Resource-Constrained Project Scheduled Problem. Using this foundation, distinct RCPSP problems were formulated to reflect real-world scenarios, particularly emphasising the port of Duisburg. Drawing upon the results, the GNN model demonstrates high efficiency and accuracy in addressing the WSSP. While traditional tools like OR TOOLS provided optimal results, the GNN model closely mirrored these benchmarks, solidifying its position as a formidable solution for complex scheduling issues, especially given its rapid computation times.
In conclusion, this research presents a cohesive understanding of various optimisation problems within the realm of inland waterway shipping, all while harnessing the power of GNNs. Through systematic exploration and application, the research underscores the potential of GNNs to revolutionise how we approach and solve these challenges, promising a future of enhanced efficiency and reliability in waterway shipping operations.
This project aims to design a power-efficient pulser for an ultrasound transducer, which is adopted in a 2D ultrasound phased-array transmitter (TX). The area of the TX circuit in a 2D phased array is limited to half of the sound wavelength, requiring an area limitation for the circuit. The transducer element used in this case has an area of 100*100 um^2. Thus, the area occupation is also considered as an important aspect through the design process.
This work designs a power-efficient 3-level high-voltage pulser with TSMC 180-nm BCD Technology. The proposed pulser interfaces an ultrasound PZT transducer with a resonant frequency of 8.15 MHz. A bootstrap structure is utilized in this design to double the 10-V supply voltage. Five switches are controlled open and close to determine the voltage level at the output node, where three control signals are needed. The design adopts stacked standard CMOS transistors instead of HV transistors for the switches. As the transistors inevitably act as one of the power-hungry parts in the circuit, a smart design of shortly close one of the switches is proposed to save more energy. The 3 levels of the output voltage level from the proposed pulser are near 0, 8 V and 15 V. Thus, as a reference for comparison, a conventional class-D pulser with a supply voltage of 15 V is also presented. It is worth mentioning that to make the comparison as fair as possible, the conventional pulser is also designed in its most power-efficient condition. The simulation result shows a 35.4% power efficiency enhancement of the proposed design compared with the conventional class-D pulser.","ultrasound neuromodulation; high-voltage pulser; Ultrasound Transducer; Ultrasound transmitter","en","master thesis","","","","","","","","","","","","Electrical Engineering | Microelectronics","",""
"uuid:e25e2eae-d799-49bf-972e-6c7d0050696c","http://resolver.tudelft.nl/uuid:e25e2eae-d799-49bf-972e-6c7d0050696c","A sustainable approach for the tunnel formwork building method","Verkade, Lars (TU Delft Civil Engineering & Geosciences)","Hendriks, M.A.N. (mentor); Schuurman, A.C.B. (mentor); Ramler, J.P.G. (graduation committee); Delft University of Technology (degree granting institution)","2023","The construction sector plays a significant role in the environment, and concrete structures constitute a substantial portion of this sector. The government is actively seeking ways to reduce the environmental impact of construction activities by promoting a more sustainable approach. In the Netherlands, a considerable number of repetitive cellular residential buildings are constructed using the tunnel formwork building method. Although this method can be enhanced in terms of sustainability by utilizing environmentally friendly cement mixtures, it poses challenges, such as an increase in execution time. This research aims to explore a more sustainable approach to the tunnel formwork building method while devising strategies to maintain the same execution time as before.
The tunnel formwork building method operates with a 24-hour daily execution cycle. During the initial 8 hours, the formwork, reinforcement, and installations are set up, followed by pouring concrete at the end of the day. After 16 hours, the concrete attains sufficient strength for the formwork to be dismantled, allowing it to be placed on the next grid. This approach results in rapid construction, high-quality output, and cost-effectiveness. However, a significant drawback is the reliance on CEM I mixtures, which consist of approximately 100\% Portland cement, contributing to substantial greenhouse gas emissions and environmental impact. Blended cement mixtures, such as CEM II and CEM III, offer more environmentally friendly alternatives by incorporating lower percentages of Portland cement blended with fly ash or blast furnace slag. Despite their environmental benefits, these mixtures exhibit a slower strength development, making it challenging to achieve a hardening time of 16 hours.
In pursuit of a dependable and sustainable approach to the tunnel formwork building method that preserves the 24-hour daily cycle, the research question is articulated as follows: ""What concrete mixtures and execution strategies can be applied in the Netherlands to diminish the environmental impact of the traditional tunnel formwork building method, utilizing sustainable cement mixtures, while upholding existing advantages in time, cost, and quality?"" This research question will guide the exploration of optimal concrete mixtures and execution measures for implementing sustainable cement mixtures within the tunnel formwork building method, while ensuring the continuity of the daily execution cycle.
In addressing this research question, an Excel calculation sheet has been developed. This sheet serves to compute the material costs, shadow costs, and formwork removal time associated with specific modifications in the design, concrete mixture, and additional execution measures for the tunnel formwork building method. The calculation sheet offers flexibility with three grid sizes: 4.5m, 6.0m, and 7.2m. It incorporates various concrete properties, such as the cement mixture (CEM I, CEM II, or CEM III), w/c ratio (0.45 or 0.55), aggregate types (fine and coarse), Blaine value (300 or 400$m^2/kg$), and admixtures (basic and additional). Additionally, the calculation sheet allows for adjustments in seasonal conditions, with options for summer (20°C) or winter (10°C)...","Tunnel formwork building method","en","master thesis","","","","","","","","2023-12-18","","","","Civil Engineering | Structural Engineering | Concrete Structures","",""
"uuid:742a9599-b11a-4a38-89d3-52ecfe12c5af","http://resolver.tudelft.nl/uuid:742a9599-b11a-4a38-89d3-52ecfe12c5af","Airtightness in the Retrofit of Historic Buildings: Investigation of a retrofit strategy for historic traditional buildings, optimizing their energy-efficiency, indoor environment quality, and heritage preservation","Ibrahim, Yara (TU Delft Civil Engineering & Geosciences)","Schipper, H.R. (mentor); Huijbregts, Z. (mentor); Labeur, R.J. (graduation committee); van der Aa, Ad (mentor); Delft University of Technology (degree granting institution)","2023","Despite being a critical aspect in improving the building stock’s environmental performance and achieving the global environmental goals, the retrofit of traditional historic buildings is hindered by a lack of comprehensive guidelines tailored to their complex building physics and heritage preservation requirements. The conventional retrofit approach – relying on the combined airtightness and insulation improvements – fail to address two decisive aspects of traditional historic buildings:
First, the air leakage is a core contributor to their bioclimatic systems and building physics balance, making its sealing detrimental to their construction durability and their Indoor Environment Quality (IEQ). Second, their heritage protection requirements restrict the conventional retrofit interventions, and particularly hinder the implementation of the mechanical systems needed to mitigate their associated risks on the building and its occupants. Accordingly, there arose an interest in challenging the conventional depiction of the air leakage as an overhead to be eliminated, and in developing a retrofit approach that preserves breathable buildings’ inherent operations by exploiting their air leakage into achieving their optimal post-retrofit performance, accounting for both energy-efficiency and IEQ.
A potential solution to the feasibility of such strategy considered a natural phenomenon characteristic of the diffuse leakage through breathable envelopes – the infiltration heat recovery (IHR) – that is conventionally neglected in building performance assessments. The intentional and efficient exploitation of this effect results in construction elements, referred to as Dynamic Insulations (DI), in which air leakage could act as a heat exchanger, diffuse ventilation source, airborne contaminant filter, and diffusion barrier. Although their original design and operations were not tailored to efficiently harvest the IHR effect, the existing breathable constructions reveal similarities with DI systems. This suggests the potential of retrofitting them to act as an efficient DI system, thus exploiting the air leakage into the building performance improvements. The present research aimed at identifying the envelope and ventilation retrofit variants that would optimize the IHR utilization through the construction, as to provide for performance improvements comparable to (or better than) the conventional approach while preserving the breathability of the construction and minimizing the heritage disruptions.
The study proposes a comprehensive framework for the assessment of the building’s post-retrofit performance, in terms of its energy-efficiency and IEQ, and investigates the relevant retrofit variants to make performance-based decisions in the retrofit design for traditional breathable buildings. This performance was evaluated using a comprehensive building performance simulation (BPS) model.
For a reliable representation of the complex building physics and air leakage dynamics of breathable constructions, the BPS integrates three sub-models: the building energy simulation (BES) model, the air leakage model, and the dynamic insulation (DI) model. Due to a lack of BES tools simulating dynamic construction properties, the well-established analytical Taylor model was adopted and adapted to the dynamic simulation tool. The analysis was implemented in EnergyPlus, for its integral Airflow Network (AFN) and advanced Energy Management System (EMS) capabilities. The model’s validation process revealed significant limitations and highlighted a need for BPS tools capable of more efficiently incorporating the dynamic behavior of building materials and their interaction with dynamic flows, particularly when seeking the tailored, efficient and non-intrusive retrofit of historic traditional buildings...
Reverse-Time Migration (RTM) is a common depth migration technique that migrates recorded wavefields from the space-time domain to the space-depth domain. It utilizes the Born approximation and the adjoint of the Born operator to produce an RTM image. However, RTM can suffer from errors, such as noise, temporal and spatial limitations, and multiple reflections.
Least-Squares Reverse-Time Migration (LSRTM) is used to overcome some of these errors. LSRTM involves resolving the reflectivity model by least-squares inversion, which is computationally expensive. Gradient-based optimization algorithms are often employed to reduce the computational burden, but they still require solving the wave equation and its adjoint for a large model in multiple iterations. One way to reduce the computational cost is by limiting the computational domain to a target region of interest.
Target-oriented LSRTM, known as TOLSRTM, focuses on the wavefield just above the target by bypassing the overburden. This approach proves beneficial when the overburden generates strong internal multiple reflections that obscure the reflections from the target area. However, a redatuming method is required to predict all orders of multiples. Marchenko redatuming is a data-driven technique that predicts the Green's functions at the boundary of the target region, incorporating all orders of internal multiples. It allows for double-sided redatuming, considering both the source and receiver perspectives. By combining the LSRTM algorithm and Marchenko double-focusing, a target-oriented LSRTM algorithm is devised that can predict interactions between the target and overburden and remove the effects of the overburden in the image. Predicting these interactions results in an artifact-free image, a better convergence rate, and a high-resolution image of the target.
Target-oriented migration algorithms typically consider only the upper horizontal boundary of the region of interest (ROI), neglecting wavefields entering the ROI from the medium beneath the lower boundary. To address this, a target-enclosed LSRTM algorithm is proposed, including both the ROI's upper and lower boundaries. Including the lower boundary provides transmission information and can improve inversion convergence. In addition, this algorithm is adopted for virtual receivers created by Marchenko redatuming. In the case of physical receivers at the boundaries of the target zone, the target-enclosed algorithm can incorporate the transmission information emanating from the lower boundary to the upper one. Consequently, when the initial model is far from the actual model, the resulting image partly recovers the long wavelength part of the model in agreement with the Born approximation criteria. Moreover, when an initial model closer to the actual model is used, the algorithm can partially recover the vertical interfaces of the perturbation. In the case of virtual receivers at the boundaries of the target zone, since the Marchenko redatuming is performed in the initial background model, the redatumed wavefields at the lower boundary suffer from kinematic errors. Therefore, the algorithm can not recover the long wavelength part of the model.
The thesis concludes with a discussion of the results obtained from applying the algorithms to marine datasets. The images resulting from the Marchenko double-focusing based target-oriented LSRTM algorithm show improvements in both resolution and artifact reduction by suppressing the overburden generated internal multiple effects. Moreover, the double-focusing enables the user to reduce the computational costs of the LSRTM algorithm and choose finer spatial sampling for the image.
An appendix proposes a formulation for integrating the target-oriented algorithms with non-linear inversion like Full Waveform Inversion (FWI). The results of this proposed algorithm show its effectiveness by reducing the internal multiple related artifacts and increasing resolution and faster convergence.","Marchenko method; Redatuming; Target-oriented; Least-squares migration; Seismic imaging","en","doctoral thesis","","978-94-6366-785-2","","","","Dr. ir. J.R. van der Neut of Delft University of Technology has contributed greatly to the preparation of this dissertation.","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:319f4f93-0590-4f9e-8029-2911f61db477","http://resolver.tudelft.nl/uuid:319f4f93-0590-4f9e-8029-2911f61db477","The development of a distributed electric propulsion (DEP) noise model","Bononi Bello, Chris (TU Delft Aerospace Engineering; TU Delft Aircraft Noise and Climate Effects)","Snellen, M. (mentor); Yin, F. (graduation committee); Smeur, E.J.J. (graduation committee); Heblij, S. (mentor); de Haan, W (mentor); Delft University of Technology (degree granting institution)","2023","","","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:be41d02b-a120-4191-96c6-1fb06e88e7c2","http://resolver.tudelft.nl/uuid:be41d02b-a120-4191-96c6-1fb06e88e7c2","Towards a circular building industry through digitalisation: Exploring how digital technologies can help narrow, slow, close, and regenerate the loops in social housing practice","Çetin, Sultan (TU Delft Real Estate Management)","Gruis, V.H. (promotor); Straub, A. (promotor); Delft University of Technology (degree granting institution)","2023","The concept of Circular Economy (CE) has emerged as a promising alternative to the current linear economy, decoupling economic activity from the depletion of natural resources and promoting a restorative and regenerative system. The transition of the building industry to a circular one can be achieved through four core resource principles: Narrow (minimising the use of primary resources), slow (extending the lifetime of buildings and products), close (regaining post-use and construction waste through reuse or recycling), and regenerate (minimising toxic substances and maximising the use of renewable resources). These principles provide a framework for exploring the role of digitalisation in the transition of social housing organisations (SHOs) toward circular housing practices, with a focus on European SHOs, particularly those in the Netherlands. This thesis follows a structured format comprising six chapters, with four of them encapsulating the author’s published articles. Chapter 1 serves as the introduction, providing a contextual foundation for the research. It outlines the overarching theme of the thesis, which revolves around the intersection of CE, digitalisation, and the built environment, with a specific focus on SHOs. The chapter sets the stage by identifying the gaps in existing literature, emphasising the need for a comprehensive conceptualisation of this emerging research field. It further delves into essential methodological aspects, the problem statement, and the broader significance of the research. In Chapter 2, the research delves into an exploration of the current state of CE implementation in Dutch SHOs and provides insights into the pressing barriers, and potential enablers. A Delphi study conducted with 21 social housing professionals reveals that, as of 2020, SHOs were in an experimental phase, incorporating circular construction techniques in pilot projects. Barriers encompass organisational priorities, operating within a linear system, and a lack of awareness. Also, financial challenges related to the costs of circular materials also emerge as significant hurdles. Chapter 3 develops a framework, the Circular Digital Built Environment Framework, in an exploratory qualitative research approach. This conceptual model integrates CE principles with digital technologies to provide an understanding of their potential applications within the built environment. The framework is constructed through expert workshops, literature reviews, and evaluations of current research and practices, resulting in the identification of over ten key digital technologies. These technologies encompass a broad spectrum, including big data analytics, blockchain technology, and material passports. The framework not only informs subsequent empirical studies but also serves as a valuable guide for scholars and industry practitioners navigating the intersection of digitalisation and circularity in the building industry. Chapter 4 presents an analysis of how enabling digital technologies, identified in Chapter 3, are practically employed in real-life practices, specifically within circular new build, renovation, maintenance, and demolition projects of forerunner Dutch SHOs. Employing a multiple-case study approach, the chapter gathers empirical evidence from three large-scale SHOs through semi-structured interviews, desk research, and extensive data analysis. The within-case and cross-case analyses reveal insights into the types of digital technologies being deployed, their impact on circular practices, and the challenges encountered in their adoption. By examining the real-world examples, Chapter 4 contributes to the evolving domain of digitalisation for a circular building industry. Chapter 5 addresses the challenges associated with data (identified in Chapter 4), with a specific focus on material passports as a crucial tool for circularity in existing housing stock. Employing a multiphase mixed-method research design, the chapter utilises the SCOPIS method (Supply Chain-Oriented Process to Identify Stakeholders) for user and data mapping. This approach results in a data template outlining the requirements of users for material passports. Subsequently, the study tests this template through a case study, identifying critical data gaps and proposing a material passports framework to address these gaps. By leveraging both digital technologies and human expertise, Chapter 5 offers solutions to enhance data management in the pursuit of circularity within the building industry. The findings contribute to ongoing industry and policy initiatives. Chapter 6, the concluding chapter, consolidates the exploration conducted throughout the thesis. It presents the overarching contributions of the research, offering a summary of the scientific and practice contributions and recommendations derived from the entire study.","cicular economy; building; digitalisation; material passports; circular buildings; social housing","en","doctoral thesis","A+BE | Architecture and the Built Environment","978-94-6366-786-9","","","","","","","","","Real Estate Management","","",""
"uuid:e82c8dd5-fbc1-46a3-b022-048d70425e2c","http://resolver.tudelft.nl/uuid:e82c8dd5-fbc1-46a3-b022-048d70425e2c","Analyse van Schuine en Kromme Liggers met de Macaulay methode: Een Diepgaande Studie","Qadriyeh, Ezzat (TU Delft Civil Engineering & Geosciences)","van Woudenberg, T.R. (mentor); Hoogenboom, P.C.J. (graduation committee); Delft University of Technology (degree granting institution)","2023","The method of Macaulay utilizes singularity functions to describe discontinuous forces acting on beam structures. This method has been extended to determine internal forces and deformation properties, where the beam is inclined at a certain angle or curved.","Macaulay's method; Singularity functions; curved beam; structural mechanics","nl","bachelor thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:77af5465-81c6-4c32-8c1e-7bc73c60a072","http://resolver.tudelft.nl/uuid:77af5465-81c6-4c32-8c1e-7bc73c60a072","Encouraging Circular Wood-Based Building Practises in Amsterdam: Encouraging Circular Wood-Based Building Practises in Amsterdam","Kleijweg, Marvin (TU Delft Technology, Policy and Management)","Bucci Ancapi, F.E. (mentor); Yorke-Smith, N. (graduation committee); Ghorbani, Amineh (graduation committee); Korevaar, G. (graduation committee); Huang, Yilin (graduation committee); Delft University of Technology (degree granting institution)","2023","The aim of this thesis project is to understand how policy instruments influence the adoption of wood-based building practices and to examine the effect of increased wood-based construction on circular practices. This study identifies key actors in the built environment, including housing associations, private owners, construction and demolition companies, and material suppliers. The behavior and relationships of these actors are analyzed. An agent-based model is developed to explore the impact of various policy instruments, such as carbon taxation, demolition notification, and knowledge sharing. The study revealed several findings. First, there is significant inertia among construction compa- nies and building owners towards adopting wood-based construction, primarily due to high initial investments and lack of familiarity. This results in a hefty premium being paid for wood-based construction before it becomes well established. It was discovered that a substantial subsidy on mass timber is essential. Additionally, significant taxation on reinforced concrete, such as through carbon taxation, helps overcome the inertia in the system. Another effective instrument is the sharing of wood-based construction knowledge among construction companies. Once wood-based construction is established, it becomes cost-competitive, reducing the need for continuous stimu- lation through policy instruments. With the establishment of wood-based construction, several effects on the circularity in the built environment and material usage have been identified. Despite a shift to wood-based construction, the demand for concrete remains significant. This underscores the importance of concrete recycling practices. The increase in wood content in construction requires enhanced mass-timber recycling practices. This study highlights the role of temporary material storage in facilitating circularity. It suggests the need for strategies to match material streams from demolition to construction. In summary, this thesis project demonstrates that a combination of policy instruments, especially carbon taxation and knowledge sharing, is crucial in transitioning to wood-based construction. The study highlights the need for continued attention to concrete use and recycling, especially when wood-based practices gain traction.","","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:bfad7b0e-f6db-49d0-8642-5e4fbc6e3861","http://resolver.tudelft.nl/uuid:bfad7b0e-f6db-49d0-8642-5e4fbc6e3861","Collaborative Payload Carrying with Multiple MAVs","Liu, Huamin (TU Delft Aerospace Engineering)","Smeur, E.J.J. (mentor); Delft University of Technology (degree granting institution)","2023","The transportation of payloads utilizing multiple drones presents a promising application for lifting heavier loads that exceed the payload capacity of a single drone. However, the cable-suspended payload introduces significant challenges to the system, and this research area remains relatively unexplored. In this work, a novel solution for payload-carrying application is proposed. First, the dynamics of cable-suspended payload transportation using multiple quadrotors, taking into account the influence of drag forces on the quadrotors are studied. A nonlinear optimization is employed to control the payload while distributing the control effort required for manipulating the suspended load over the drones in the formation while ensuring both tension constraints and collision avoidance between drones in the formation. The feasible path commands for formation agents are computed from the optimization. One of the critical aspects for controlling such a system is the load-introduced force, which exhibits rapid and complex variations. To address this, an extended state observer is employed to estimate the load force, eliminating the need for a tension sensor. In pursuit of a robust framework, a formation reset strategy is also developed, allowing to maintain load tracking performance and ensure the safety of formation agents, even in the event of a malfunction in one of the drones. A series of simulations are conducted to validate the effectiveness and robustness against disturbance and suspension failure of the proposed strategy and controllers. Results demonstrate that the whole multi-lift system can handle external disturbances, model uncertainties regarding drone inertia, mass and load mass, as well as suspension failures.","payload transportation; tension optimization; extended state observer; formation recovery","en","master thesis","","","","","","","","2025-12-15","","","","Aerospace Engineering | Control & Simulation","",""
"uuid:a5d0945b-92f9-40c9-a84f-6d4b2a162ea4","http://resolver.tudelft.nl/uuid:a5d0945b-92f9-40c9-a84f-6d4b2a162ea4","Electric Ground Support Equipment at Airports: The impact of implementing eGSE on the capacity and demand of GSE fleets","Timmermans, Koen (TU Delft Mechanical, Maritime and Materials Engineering)","Atasoy, B. (mentor); Roling, P.C. (mentor); Chandra Mouli, G.R. (graduation committee); Troquete, R.P.M.H.G. (mentor); Wiebenga, G. (mentor); Delft University of Technology (degree granting institution)","2023","Airports and airlines are examining and committing to the electrification of Ground Support Equipment (GSE). To be able to estimate the required quantity of eGSE, the charging requirements of eGSE, the change of airport electricity requirements, and the scheduling possibilities of eGSE charging for the existing turnaround procedures, a model was developed to simulate and optimize the GSE operations at airports. This was done by means of a Task Scheduling Problem (TSP), that is optimized using Mixed-Integer Linear Programming (MILP). A case study was performed on KLM's GSE fleet at Amsterdam Airport Schiphol. Based on this, it was concluded that there is no difference in the capacity that can be achieved for GSE types that can last an entire day on a single battery charge. However, another group of GSE types experiences battery depletion before the day concludes, requiring measures to maintain the capacity. The results indicate the model's suitability for strategic decision-making. Next to that, the model is effective on an operational level. The use of the model has the potential to make the use of resources in the operation more efficient.","electric ground support equipment; airport operations; ground handling; multi-objective optimization; vehicle scheduling; fleet optimization; KLM; Amsterdam Airport Schiphol","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Multi-Machine Engineering","",""
"uuid:34213dbf-32ad-4f8d-b0f0-ed398608d682","http://resolver.tudelft.nl/uuid:34213dbf-32ad-4f8d-b0f0-ed398608d682","Modular Neural Network Navigation for Autonomous Nano Drone Racing","Magri, Federico (TU Delft Aerospace Engineering)","de Wagter, C. (mentor); de Croon, G.C.H.E. (mentor); Ferede, R. (mentor); Bahnam, S.A. (mentor); Delft University of Technology (degree granting institution)","2023","In this study, we present a first step towards a cutting-edge software framework that will enable autonomous racing capabilities for nano drones. Through the integration of neural networks tailored for real-time operation on resource-constrained devices. A lightweight Convolutional Neural Network, with the Gatenet architecture, is adjusted for reduced computational demand and is successfully deployed on a GAP8 processor at a rate of 16$Hz$. This network provides gates' size and location data for the subsequent positioning algorithm. A second neural network, trained through reinforcement learning, governs the drone's guidance and control systems, demonstrating a remarkable rate of 167$Hz$ on an STM32F405 processor. The attitude rates and thrust outputted by this network are then fed to an attitude rate PID controller.
The research shows that state-of-the-art neural networks for drone racing can be deployed on nano drones, despite their limited processing power. Nonetheless, the study demonstrated specific limitations, such as the perception network's sensitivity to white pixels in the image reducing its effectiveness when light sources are present in the scene. These findings underscore the importance of dataset composition and the need for diverse training scenarios to enhance the neural network's generalizability and performance in real-world applications.","Reinforcement Learning; Convolutional neural network; Nano Drones; Quantization","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:4c3523d3-5f5a-4293-a7ec-6a0b40a596c0","http://resolver.tudelft.nl/uuid:4c3523d3-5f5a-4293-a7ec-6a0b40a596c0","Protection Study of MTDC power system","Sai Nair, Vishnu (TU Delft Electrical Engineering, Mathematics and Computer Science)","Popov, M. (mentor); Lekić, A. (graduation committee); Liu, L. (graduation committee); Delft University of Technology (degree granting institution)","2023","This thesis investigates and compares the performance of HVDC protection algorithms in terms of their sensitivity, selectivity, speed, and robustness. The threshold determination process for each algorithm has been described in detail as well. Each algorithm is tested under various fault resistances, and fault distances to test the sensitivity of the algorithm. The trip time for each case in each algorithm is monitored to analyze the speed of the algorithm. Various external faults have been simulated to test the selectivity of the algorithm. Lastly, the resilience of each algorithm against white noise has been tested. Furthermore, the effect of varying the sampling frequency and the inductance of the current limiting inductors on each algorithm is investigated. The HVDC protection algorithms discussed are - current differential deviation-based protection, ROCOV-based protection, ROCOC-based protection, and DC reactor voltage change rate-based protection. All protection algorithms have been implemented in the PSCAD environment. The noise resilience analysis for each algorithm has been performed in MATLAB.","HVDC; protection measures; Algorithms","en","master thesis","","","","","","","","","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:5a54364d-6642-46f0-929f-0d3ba72c23f5","http://resolver.tudelft.nl/uuid:5a54364d-6642-46f0-929f-0d3ba72c23f5","Auditing Artificial Intelligence","Sewandono, Tijn (TU Delft Technology, Policy and Management; TU Delft Values Technology and Innovation)","Renes, Sander (mentor); Ding, Aaron Yi (graduation committee); Delft University of Technology (degree granting institution)","2023","Recent technological advancements have enabled the development of increasingly impactful and complex Artificial Intelligence (AI) systems. This complexity is paired with a trade-off in terms of system opacity. The resulting lack of understanding combined with reported algorithm scandals have decreased public trust in AI systems. Meanwhile, the AI risk mitigation field is maturing. One of the proposed mechanisms to incentivize the verifiable development of trustworthy AI systems is the AI audit: the external assessment of AI systems.
The AI audit is an emerging subdomain of the Information Technology (IT) audit, a standardized practice carried out by accountants. Contrary to the IT audit, there are currently no AI-specific defined rules and regulations to adhere to. At the same time, some organizations are already seeking external assurance from accountancy firms on their AI systems. AI auditors have indicated that this has lead to challenges in their current audit approach, mainly due to a lack of structure. Therefore, this thesis proposes an AI audit workflow comprised of a general AI auditing framework combined with a structured scoping approach.
Interviews with AI auditors at one accountancy firm in the Netherlands revealed that the demand for AI audits is increasing and expected to keep growing. Clients mainly seek assurance for management of stakeholders and reputation. Furthermore, the challenges the auditors currently experience stem from having to aggregate auditing questions from a range of auditing frameworks, causing issues in their recombination and in determining question relevancy. Subsequently, design criteria for a general auditing framework as well as feedback on a proposed scoping approach were obtained.
Fourteen AI auditing frameworks were identified through a literature search. Following their typology, these could be subdivided into three source categories: academic, industry, and auditing/regulatory. Academic frameworks typically focused on specific aspects of trustworthy AI, while industry frameworks emphasized the need for public trust to drive AI progress. Frameworks developed by auditing and regulatory organizations tended to be most extensive.
Comparison to four common IT audit frameworks and standards showed that AI audit frameworks need to cover a broader range of topics than the traditional IT audit themes. This is a result of the complex socio-technological context involving multiple stakeholders in which AI systems operate. Additionally, it was shown that AI performance monitoring dashboards could cover technical parts of the audit, but that they fall short when it comes to context-dependent topics such as human oversight or societal well-being.
Following analysis of the similarities between the corporate Environmental, Social and Governance (ESG) reporting materiality assessment and the AI audit scoping problem, an ESG materiality assessment approach was translated to a scoping approach for the AI audit. In this translation, feedback from the AI auditors was incorporated. Combined with a general auditing framework, which was built through combination of the fourteen identified frameworks along the obtained design criteria, this formed the basis for the proposed AI audit workflow. The proposed workflow was demonstrated to be executable through a mock case study. Investigation from the data subject perspective for the Public Eye crowd monitoring AI system of the Municipality of Amsterdam resulted in a scoped list of auditing questions relating to privacy, transparency and fairness.
Recommendations for future AI audit workflow designs include exploring the option of incorporating subthemes in the general framework, closer co-development with AI auditors, obtaining insights from auditors at multiple accountancy firms, and automating parts of the audit.","Artifical Intelligence; Auditing; Trustworthy AI","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:f1c1fcb8-6da1-483b-804f-45ff5120b427","http://resolver.tudelft.nl/uuid:f1c1fcb8-6da1-483b-804f-45ff5120b427","Feedering Method Analysis for 20 MW Offshore Wind Turbine Installation in the U.S.","van Wilsem, Rick (TU Delft Mechanical, Maritime and Materials Engineering)","Kana, A.A. (mentor); Jarquin Laguna, A. (graduation committee); Khosravi, M. (graduation committee); van den Munckhof, Sven (graduation committee); Delft University of Technology (degree granting institution)","2023","The Jones Act, limited US port facilities, and absence of Jones Act-compliant installation vessels pose significant challenges for offshore wind farm installations. These factors force contractors to explore new installation strategies, such as feedering. Feedering is an installation strategy where the wind turbine installation vessel remains stationed at the offshore wind farm, while a feeder vessel transports all wind turbine components from the marshaling port to the installation site. With the rise of U.S. wind farm developments on the East Coast, it becomes apparent that alternative vessel designs and strategies will play a vital role in the near future. Therefore it is crucial to gain an understanding of Jones Act complaint vessel designs and strategies.
In this thesis, a new method for optimizing feeder vessel design concurrently with a wind turbine installation strategy is introduced. The approach combines multi-agent discrete-event simulation and design space exploration to define the optimum within the design space. The proposed method facilitates the evaluation and comparison of the operational performance of design configurations using historical environmental data, operating limits, and operational characteristics. Importantly, the proposed approach accommodates for the interdependency of operations making it suitable for the design and evaluation of repetitive multi-tasked operations. This method provides an improvement over the commonly used workability percentage and thereby allows for improved and fit-for-purpose designs.
A case study is performed based on Vineyard Wind WTG installation works that shows the potential of the proposed approach and the impact of vessel size, installation strategy and equipment characteristics on operational performance. This research offers new insights into the optimization of offshore wind farm installation processes and vessel designs paving the way for more efficient and effective installations in the rapidly growing U.S. wind energy sector.
Staphylococcus aureus","van Heuckelum, Joran (TU Delft Applied Sciences)","de Kruijff, R.M. (mentor); Hagedoorn, P.L. (mentor); Apachitei, I. (mentor); Bokinsky, G.E. (graduation committee); Delft University of Technology (degree granting institution)","2023","div>Implant-associated infections by antibiotic-resistant biofilm-forming pathogenic bacteria such as Staphylococcus aureus have become a growing concern as they are difficult to treat and lead to implant revision surgery. Implant coatings consisting of superparamagnetic iron oxide nanoparticles may prevent the attachment to and infection of implants by bacteria. However, these nanoparticles release iron, which is also a nutrient necessary for bacterial growth, and may inadvertently contribute to infection. In this thesis the uptake of iron from iron nanoparticles by S. aureus is investigated.
What are the barriers and success factors in public-private partnerships that focus on experimental development, and how do the participants cope with the barriers, and utilize the success factors?
From the literature a theoretical framework was set up based on four categories of factors influencing the innovation process. The categories are organizational, contextual, interaction-specific, and innovation-characteristic. Literature suggested that interaction-specific barriers were the main source of barriers. The main strategies in literature revolve around interaction-specific solutions to these interaction-specific barriers. A contextual model was set up.
Dutch Ministry of Defence (MoD) and the Dutch Defense industry provided a novel research setting with hard-to-define innovation goals. Individuals from both sides of the PPP with practical experience in PPPs that focus on experimental development were interviewed. Within the Dutch MoD these were innovation coordinators within sub-organizations and within the Defense Industry these were leaders of small to medium-sized companies. The data was gathered through 13 interviews, of which 11 were used as sources of data. The data was first deductively coded through the four categories and then inductively coded based using the terminology of the interviewees.
This coding strategy led to three organizational factors: ‘process rules’, ‘culture, vision & implementation’ and ‘scale-up’, five contextual factors: ‘procurement: general’ ‘procurement: prior knowledge’, ‘procurement: perception’, ‘privacy’ and ‘technology-related’, one innovation-characteristic factor: ‘uncertainty’ and three interaction-specific factors: ‘contact with end-user’, ‘shared understanding’ and ‘expectation management’. The factors were described as ‘barrier’, ‘success factor’, ‘strategy’, and ‘not a barrier’. Organizational and contextual factors were the main factors influencing the success of the innovation process. ‘Process rules’ was named the most influencing factor for the innovation process. ‘Procurement law’ was the most prominent contextual factor. Innovation-characteristic factors were often considered to not be relevant to the cooperative innovation process. Lastly, the interaction-specific factors were occasionally cited as a barrier and often named as a success factor, specifically ‘contact with end-user’. Interaction was key to most strategies employed to overcome barriers.
In conclusion, this study has provided a unique insight into a collaborative phenomenon in a scarcely researched setting. The findings can be used in comparison with other research on PPPs with innovative goals, especially those that have taken place in the Netherlands. Compared to literature, the appearance of interaction-specific strategies is not unique, but in their broad application to overcome a plethora of barriers is. Further research focusing on communication dynamics within PPPs is recommended to enhance collaborative efforts and drive impactful innovations in the Defense sector. In a practical sense, reviewing process and contextual rules and reviewing the accessibility of the PPP to newcomers in the sector would enhance innovation programs, fostering effective collaboration between public and private entities.","Public-private partnerships; innovation; Experimental Development; Barrier; Strategy; Defence","en","master thesis","","","","","","","","","","","","Management of Technology (MoT)","",""
"uuid:7f4fe83d-6e9d-40cd-a303-4c579f02eda1","http://resolver.tudelft.nl/uuid:7f4fe83d-6e9d-40cd-a303-4c579f02eda1","Generating reversible interlocking structures for non-compatible FDM polymers","van Zeijl, Thomas (TU Delft Industrial Design Engineering; TU Delft Sustainable Design Engineering)","Doubrovski, E.L. (mentor); Ozdemir, Mehmet (graduation committee); Delft University of Technology (degree granting institution)","2023","In the field of 3D printing, Multi Material Additive Manufacturing (MMAM) has gained substantial recognition, as it offers interesting new possibilities. MMAM allows the combination of diverse polymers to create products with enhanced, composite properties. However, a significant challenge emerges when chemically incompatible polymers are combined within this technique, which complicates recyclability. This research addresses the issue of connecting these polymers while preserving strength, durability, and the capacity for disconnection, which facilitates efficient recycling at the end of a product’s life cycle.
Polymers, while versatile and widely used, often prove to be chemically incompatible due to their distinct chemical compositions and inherent characteristics. This incompatibility becomes a major bottleneck in the field of MMAM, as it obstructs the effective adhesion of polymers to each other. The result is products that are exceedingly challenging to recycle, perpetuating a long-standing issue in the 3D printing domain. Conventional industry solutions, primarily reliant on mechanical interlocking methods, lack the necessary flexibility for disassembly, rendering the materials inseparable and hindering recycling. This issue has long hampered the establishment of a sustainable 3D printing ecosystem.
To conquer this challenge, this research introduces the “Z-pin” connection, a novel reversible interlocking method. The Z-pin method serves as a bridge connecting chemically incompatible polymers and offers an approach that exceeds current alternatives. The introduction of the Z-pin’s design helps the joining of different polymers while still facilitating their clean separation when necessary.
The Z-pin method is most novel in its remarkable capacity for disconnection. By subjecting the polymer connection to controlled heating, within a range of 60 to 95 degrees Celsius, this method facilitates the simple, clean, and efficient separation of materials. Most notably, this process can be executed with basic tools and, in certain scenarios, by manual disassembly.
The developmental process of the Z-pin method comprised three phases. The first phase involved the initial design and evaluation of a range of connection methods. Two methods that demonstrated great potential were selected for further refinement in the second phase. Here, an optimisation process took place, including geometry, print parameters, and material properties. The third phase was dedicated to implementing the enhancements identified in phase two, culminating in a comprehensive and finalized design. This iterative methodology addressed the extensive range of possibilities uncovered during preliminary research.
The research affirms the performance of the Z-pin method over conventional solutions, including the hacksaw and alternating layer methods. The Z-pin method has an impressive tensile strength, positioning it as a contender within the MMAM domain. Furthermore, its straightforward geometry affords scalability and adaptability, enabling it to meet the specific prerequisites of a diverse array of applications.","3D printing; Multi-Material Additive Manufacturing; non-compatible polymers; PLA; TPU; interlocking; Sustainable; Recycling","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:3d84cde7-996f-4b95-8a63-abc589f7243b","http://resolver.tudelft.nl/uuid:3d84cde7-996f-4b95-8a63-abc589f7243b","Navigating the Energy Transition: A Comprehensive Modeling Approach for the Netherlands","Akaouche, Anass (TU Delft Electrical Engineering, Mathematics and Computer Science); Hameed, muasser (TU Delft Electrical Engineering, Mathematics and Computer Science)","Cvetkovic, M. (mentor); Delft University of Technology (degree granting institution)","2023","This report presents an energy transition model that emphasizes the importance of prioritizing innovation. It demonstrates the potential energy savings achievable through the installation of insulation layers. Additionally, it explores the increasing adoption of electric vehicles (EVs) and its influence on energy consumption within the transportation sector. The report also discusses renewable energy sources and explores energy storage methods. Lastly, the report concludes by highlighting the need for a balance between energy supply and demand, acknowledging that traditional energy sources will continue to be necessary in 2030, aligning with expectations. This comprehensive analysis serves as a foundation for future research endeavors aimed at developing a more precise model.
In the final project, the findings are implemented in a design for a new theatre in Gouda. The design aims to create a more open, attractive and efficient theatre that will attract a wide variety of audiences. All while dealing with the challenges of the location: subsidence, water nuisance and urban heating. The new building gives space to the theatre and the neighboring community centre. A large underground storage, roof ponds and rain-curtain facades all add to a resilient and characteristic new theatre building and a comfortable indoor and outdoor climate.","Pluvial flooding; Urban Water System; Rainwater harvesting; Rainwater storage; Climate Design; Evaporative Cooling; Aquathermal energy; Thermal Energy Storage; Theatre Design","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Architectural Engineering","","52.01615366952468, 4.7120583306871895"
"uuid:de7f1d3e-3c86-4886-88ba-82046959da15","http://resolver.tudelft.nl/uuid:de7f1d3e-3c86-4886-88ba-82046959da15","Sense of Place within Transience: Reconfiguring housing efficiency and resilience in Sao Paulo’s peripheral urban condition","Torbica, Angelina (TU Delft Architecture and the Built Environment)","Mota, Nelson (mentor); Mooij, H.A.F. (mentor); Schnater, F.R. (mentor); Delft University of Technology (degree granting institution)","2023","Sao Paulo, Brazil, a megacity home to 22.4 million inhabitants as of 2022 has “one of the most inequitable distributions of wealth in the world” (Caldeira 1996, 303). In the various districts, the inequality either shouts or whispers its presence. An open city, where the street-scape is the backdrop for social convergence, segregates itself in Sao Paulo as a space of clear definition of the haves and have-nots. Within the urban condition “…the physical distances separating rich and poor have decreased at the same time that the mechanism to keep them apart have become more obvious and more complex” (Caldeira 1996, 304). As Brazil’s economic and political conditions exponentially shifted so did the reshaping of the built landscape – with that, the right to the city for the urban poor became intangible. Through the process of ‘autoconstruction’ even the poorest of citizens could gain access to the city. However, due to economic restructuring, new generations are even more at a disadvantage to precarious living conditions.
On the opposite spectrum, for the well-off, the current city skyline is arrayed with inward turned urban enclaves; congruently polarizing amenities once connected to the public street (i.e., parks, residential complexes, schools). These vertical communities retain all that is necessary within a private and autonomous space and can be positioned almost anywhere, independent of their context. In many cases, they are placed at the periphery directly neighboring auto-constructed settlements. As Caldeira coins it, “…Sao Paulo is today a city of walls” as the disparity between classes became something quite defined and accepted with the fear of crime fueling changes to all forms of public exchange (Caldeira 1996, 307). Within this, emerges a dynamic, one of codependence. The poor rely on the city for financial prosperity; the wealthy rely on the labor of the poor.
As the government begins to address housing for the city’s most marginalized through large-scale residential blocks – as a means to domesticate the transient realities of Sao Paulo’s contemporary urban condition - the notions of social segregation are still wide and apparent. As the favela is stigmatized with housing a certain social class, so is the governmental housing, and so is the urban enclave. Each environment has become categorical; of separate and unequal atmospheres devoid of connection. However, is there a way for these atmospheres to communicate? In his book, Building and Dwelling: Ethics for the City, Richard Sennett refers to three types of repair: restoration, remediation, and reconfiguration. In the case of Grajau – a peripheral district of Sao Paulo constituting for a majority of the city’s urban poor – Sennett’s ideas of repair can be disseminated within its changing context. Restoration, looking to accept the exiting approaches to marginalized housing. The second, remediation, looking to build upon existing solutions, interchanging and exchanging certain elements for an improved whole. Lastly, reconfiguration giving space for new typologies with the use of existing forms. This brings into question:
How could a kit-of-parts approach marry the efficiency of a top-down approach & the resilience of a bottom-up approach to enable place-making in self-built settlements of Grajau?
a. How can participatory process be a part of the planning process for social housing?
b. What spatial structures help create/enable the development of social cohesion in self-built settlements?
c. How can a catalogue of dwelling types adapt and meet community needs over time?
Multiple tests were conducted on the well to answer several questions. The slug test indicated that the fracture is still open and essentially confirmed that it is a shear fracture, however it is unclear to what extent that the fracture is open. The fracture seems to be hydraulically connected to a permeable unit or shallow aquifer. Unfortunately, the length of the fracture could not be determined with the data collected from the test.
Electrical resistivity tomography (ERT) and seismics were both applied to a location near the borehole to acquire lateral information of the subsurface. The ERT results showed that the layers were horizontally continuous and indicated layers with different compositions based on resistive properties.
Seismic refraction tomography conducted along a part of the same profile showed similar results as the ERT for that part of the profile. P-wave velocities indicate a horizontally layered subsurface in the upper 40m. Additionally surface wave analysis of the same setup utilizing active and passive measurements resulted in a vertical s-wave velocity profile that can be used for future implementation of the planned Borehole Thermal Energy Storage (BTES) system.
The last geophysical method was using gravity data on the region around the site. A map was made by using available data on changes in gravity in the region and plotting the results. On this map the location of remnants of volcanos and the Litoměřice deep fault can be recognised.
Thermal properties of cores were analyzed using a Hot Disk and an optical scanner. Unfortunately the drilling of a new well from which the cores were to be analyzed was delayed, and cores from an uranium mine were used. This way the advantages and disadvantages of both measuring devices could be argued and used for future research.
Past analysis of geothermal regions have shown that exploration of geothermal energy causes surface displacement. It can also be observed during the drilling phase. Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite System (GNSS) are valuable tools to monitor land surface changes. Measurement of surface deformation being one of its many applications. For this study, the above tools have been used to measure surface displacement in the region of Litoměřice.
The design alternatives centres on measures to counteract flooding, specifically cloudburst roads, retention areas, and a promenade. Caution is advised in interpreting results, emphasizing the need for further investigation into hydraulic conditions. Climate change effects are underscored, considering sea level rise, precipitation rates, and increased hurricanes. The project area, focusing on a 1 km stretch, offers local adaptation measures, with potential extension to larger areas to explore system behaviour on a larger scale. The study notes the uncommon implementation of sustainable drainage systems in the United States,
highlighting the importance of addressing common failure causes such as incomplete knowledge and poor communication. While two measures for pluvial flooding are examined, the report suggests a more detailed design should consider additional factors like green roofs and their impact on runoff speed and drainage capacity.","Galveston; Flooding resilience; sustainable drainage systems (SuDS); multidisciplinary project","en","student report","","","","","","","","","","","","Civil Engineering","",""
"uuid:55cdb9af-c4b0-4d31-a34f-9f4ca57aeefa","http://resolver.tudelft.nl/uuid:55cdb9af-c4b0-4d31-a34f-9f4ca57aeefa","A Spatial Dialogue in the emerging city of Addis Ababa: Bridging the Gaps between Informality and Formality","Zeru, Feven Gebeyehu","Mota, Nelson (mentor); Reinders, L.G.A.J. (mentor); van den Ban, R.R. (mentor); Sariyildiz, I.S. (graduation committee); Delft University of Technology (degree granting institution)","2023","The Master's thesis ""A Spatial Dialogue in the emerging city of Addis Ababa"" explores the intricate dynamics between formal and informal housing in Addis Ababa, Ethiopia. Authored by a German-Ethiopian architectural designer, the thesis critically examines the oversimplified categorization of traditional ""sefer"" settlements and modern condominiums, shedding light on their impact on social, economic, and cultural aspects.
Through the combination of architectural and ethnographic research methods, the study uncovers the unique cultural nuances and spatial needs of Ethiopian dwellers. It challenges stereotypes associated with informal settlements, revealing unexpected similarities in how residents creatively appropriate their homes, irrespective of architectural differences. The subsequent design proposal for a housing complex in Yeka Abado integrates formal and informal elements, emphasizing flexibility, communal spaces, and income-generating opportunities.
The thesis advocates for a holistic, inclusive approach in architecture, emphasizing the importance of incorporating cultural heritage and community engagement. The design project serves as a conceptual exploration rooted in extensive research, aiming to bridge the gap between modern design concepts and traditional practices for inclusive and culturally responsive housing solutions.","social housing; Addis Ababa; informality; formality; Sefer; Condominium; incrementally; living culture; modular housing; Compressed Earth Block; Yeka Abado; appropriation; socio-spatial; Ethnography; flexibility","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Building Technology","","9.005401, 38.763611"
"uuid:fb0cc4b7-a67b-474b-9570-96eb054a39ec","http://resolver.tudelft.nl/uuid:fb0cc4b7-a67b-474b-9570-96eb054a39ec","WebDSL: Linguistic Abstractions for Web Programming","Groenewegen, D.M. (TU Delft Programming Languages)","van Deursen, A. (promotor); Erdweg, S.T. (promotor); Delft University of Technology (degree granting institution)","2023","Information systems store and organize data, and manage business processes concerned with that data. Information systems aim to support operations, management and decision-making in organizations. Web applications are ideal for implementing information systems. Although existing web frameworks provide abstractions for creating web applications, there are three major issues with current web frameworks. Insufficient or leaky abstraction: web programming concerns are not sufficiently covered or abstractions contain accidental complexity. Lack of static verification: application faults are not removed during development. Security flaws: web application security issues are not sufficiently addressed in the framework, web programmers are exposed to many possible security faults.
How can the benefits of web frameworks be provided for web programming while avoiding the major issues of abstraction, static verification, and security? We propose a domain-specific language (DSL) solution. The challenge is to design a language that provides abstractions for all kinds of web programming tasks with the web framework issues in mind. We designed multiple sublanguages to address web programming concerns, and integrated them to form the WebDSL web programming language. WebDSL incorporates better abstraction for web programming concepts, has static checks on the application code with accurate error reporting, and automatically addresses security concerns in the code generation and runtime.
The primary concerns in web programming are user interfaces and data handling. Which features do we need from a user interface language? These features include both the rendering of data persisted in the database, as well as providing input-handling components to enter new data and update existing data. Additionally, data invariants need to be enforced by the system. How can a DSL provide these features in an integrated way? These are language-design challenges that are investigated in this dissertation. The user interface sublanguage of WebDSL contains several unique improvements compared to existing approaches: form submits that are safe from hidden data tampering; prevention of input identifier mismatch in action handlers; safe composition of input templates; automatic enforcement of Cross-Site Request Forgery protection; expressive data validation; and partial page updates without explicit JavaScript or DOM manipulation.
Access control is essential for the security and integrity of interactive web applications. Existing solutions for access control often consist of libraries or generic implementations of fixed policies. These rarely have clear interfacing capabilities, and they require manual extension and integration with the application code, which is error-prone. WebDSL provides a declarative access control sublanguage, which is entirely integrated with other language components and automatically weaves checks into the application code. Errors related to inconsistent application of access control checks are avoided. The access control language shows that various policies can be expressed with simple constraints, allowing concise and transparent mechanisms to be constructed.
Our work on abstractions for web programming resulted in several scientific and software contributions: The design and implementation of a linguistically integrated domain-specific language for web programming that combines abstractions for web programming concerns covering transparent persistence, user interfaces, data validation, access control, and internal site search. Sublanguages for the various concerns are integrated through static verification to prevent inconsistencies, with immediate feedback in the integrated development environment (IDE) and error messages in terms of domain concepts. WebDSL is the largest programming language created with the Stratego program transformation language and the Spoofax language workbench, in which the DSL compiler and IDE have been iteratively developed. This iterative development is a recurring pattern of discovering new abstractions, domain-specific language abstraction, and reimplementation using new core abstractions tailored to the language. To validate WebDSL, we have created several real-world applications in the domain of research and education for external clients.
In our research we aim to create solutions for problems in web engineering and language engineering by developing concepts, methods, techniques, and tools. We aim to create more than just prototypes by continuing maintenance and development beyond the proof of concept. For over 10 years, we have developed WebDSL, and created and operated practical applications for external clients. For example, EvaTool is a course evaluation application that supports processes for analyzing student feedback by lecturers and other staff. WebLab is an online learning management system with a focus on programming education (students complete programming assignments in the browser), with support for lab work and digital exams, used in dozens of courses at TU Delft. Conf Researchr is a domain-specific content management system for creating and hosting integrated websites for conferences with multiple co-located events, used by all ACM SIGPLAN and SIGSOFT conferences. MyStudyPlanning is an application for composition of individual study plans by students and verification of those plans by the exam board, used by multiple faculties at TU Delft.","Programming Languages; Programming Language Design; Domain-Specific Languages; Web information systems; compilers; Information Systems; Access control; Data validation; User Interfaces; Persistence; Object-Relational Mapping; practical impact","en","doctoral thesis","","978-94-6419-976-5","","","","Prof.dr. E. Visser (Delft University of Technology) was the original promotor and supervisor of this research until his untimely passing on April 5th, 2022.","","","","","Programming Languages","","",""
"uuid:b4091579-66ea-4401-9277-dffe5a83ab90","http://resolver.tudelft.nl/uuid:b4091579-66ea-4401-9277-dffe5a83ab90","Upstream process development for cultured red blood cell production","Gallego Murillo, Joan Sebastián (TU Delft BT/Bioprocess Engineering)","van der Wielen, L.A.M. (promotor); Wahl, S.A. (promotor); von Lindern, Marieke (promotor); Delft University of Technology (degree granting institution)","2023","Production of cultured red blood cells (cRBCs) hold the promise of being a potentially unlimited source of cells that could cover the increasing demand of RBCs for transfusion purposes, while having more control on the quality and safety of the cells compared to the current donor-dependent system. cRBCs could also be used for novel therapies in which cells are used as carriers of therapeutic molecules. Scaling up cRBC manufacture is essential to produce the large number of cells needed for such applications. However, scaling up the current static culture systems for the production of erythroblasts (RBC precursor cells) would be prohibitively labor-intensive, requiring large volumes of medium and a high footprint. The work presented in this thesis aims to develop solutions to some of the key challenges in the scaling up of cRBC manufacture.
Stirred tank bioreactors (STRs) are the standard for the large-scale production of biopharma therapeutics, including monoclonal antibodies and vaccines. Agitation in this type of reactors can reduce the concentration gradients of essential nutrients compared to static culture systems such as culture dishes. STRs also offer active control of critical operating parameters in the culture, such as dissolved oxygen concentration, pH and temperature. We therefore developed a culture protocol for the proliferation and differentiation of erythroblasts in STRs (Chapter 2). To define the operating conditions that sustain erythroblast proliferation in STRs, the effect of agitation, aeration strategy, and dissolved oxygen concentration was evaluated using 0.5 L STRs. Using this knowledge, the cultivation process could then be scaled up to 3 L bioreactors.
Erythroblasts lose their replication capacity when transitioning from proliferation to differentiation culture conditions. Thus, efficient proliferation of erythroblasts is essential to produce the large number of cells required for cRBC manufacture. Growing erythroblasts under proliferative conditions is typically performed following a repeated-batch cultivation strategy, in which the culture is diluted every 24 hours with fresh medium to a fixed lower cell concentration. To reduce culture volumes, it is desirable to use higher cell concentrations. However, at increasing cell densities we observe a decrease in growth (Chapter 3). The observed growth limitations of erythroblast cultures at high cell densities appeared to be caused by depletion of low molecular weight nutrients (molecular mass <3 kDa) in the spent medium. We quantified consumption rates of amino acids, major contributors to biomass synthesis in proliferating mammalian cell cultures. Although the concentration of some amino acids decreases considerably over time, supplementation with additional amino acids did not improve growth. Following an untargeted metabolomics approach, we identified multiple pathways that indicate an excess of oxidative stress in erythroblast proliferation cultures.
Perfusion proved to be a successful alternative cultivation strategy to overcome growth limitations due to depletion of nutrient components (Chapter 3). Increasing the maximum cell concentration in erythroblast cultures leads to an increase in the volumetric productivity (number of cells produced per reactor volume per culture time), which decreases the reactor volume needed to produce the same amount of cRBCs. However, large volumes of medium would still be required to sustain those cultures. Currently, the cost of culture medium for erythroid cultures makes cRBC manufacture economically unfeasible. Growth factors and proteins added to the medium are major contributors to the cost of the medium. Holotransferrin, an iron-carrying protein, is the main cost driver in erythroblast differentiation medium. We show that holotransferrin in erythroblast cultures can be replaced by a GMP-compatible iron chelator (deferiprone; Def), bound to ferric ion (Def3⋅Fe3+; Chapter 4) . Addition of Def3⋅Fe3+ to the culture medium resulted in similar final cRBC yields of cRBCs during proliferation and differentiation of erythroblast cultures compared to optimal holotransferrin concentrations. During differentiation, Def3⋅Fe3+ fully supported enucleation and hemoglobinization. We did not observe toxic effects of Def3⋅Fe3+.
Finally, the main conclusions of this thesis are discussed, providing also an overview of the next developments that are required to make the production of cRBCs at large scale technically and economically feasible (Chapter 5). A multidisciplinary approach is needed to further reduce media cost, optimize medium composition to improve cell yields, and to improve the bioreactor culture system developed in this work.
Conventional voltage control schemes assume a unidirectional power flow (i.e., consumption only) in distribution grids and are unable to keep the limits in case a large share of generation capacity is installed. This is further complicated by the fact that underground cable networks, typical in Western European electricity distribution grids, have lines with large R/X ratios, which reduces the effectiveness of reactive power injection-based voltage control methods.
This MSc project intends to solve the issue of voltage limit violations with a model predictive control (MPC) policy. The considered control actions coordinated by the model predictive controller are the switching of the on-load tap changer (OLTC) mechanism mounted to the primary substation’s transformer, setpoint adjustments of the low-level OLTC control relay, and the active power curtailment of larger photovoltaic plants. A linear, sensitivity-matrix-based model is used for the grid’s state prediction; and the sensitivity values are re-calculated at each sampling time step of the MPC. To avoid the curtailment of photovoltaic (PV) plants when not justified, a conditional curtailment logic is incorporated into the MPC policy: PV plants are only allowed to be curtailed if their local voltage magnitude is above a tuneable threshold. This logic is described and incorporated into the model predictive controller’s optimization problem with the help of binary variables and mixed-integer linear (MIL) constraints. The benefit of incorporating knowledge about future disturbances (load, generation, and external grid voltage profiles) is also tested, in order to assess the potential benefit DSOs could get from forecasting these quantities.
A case study was conducted in which the considered controllers were tested on a section of a Stedin grid that carries the characteristics of a typical Western European medium voltage distribution grid: large R/X ratios and a large installed PV generation capacity both in the form of household generation and larger PV plants. All controllers were simulated in 4 different test cases: a typical summer day, a summer day with the external grid’s overvoltage, a summer day with 2 out of 3 large PV plants not operating, and a typical winter day. All test cases have the control goals of mitigating limit violations and ensuring that the nodal voltage magnitudes are as close as possible to the nominal 1 per unit throughout the day. The winter day test case has the additional goal of avoiding excessive curtailment as PV energy is worth considerably more during these days. All profile data is based on real Stedin measurements. The designed model predictive control policies are compared to two simple control schemes: current compounding, i.e. when the primary substation’s automatic voltage control relay’s setpoint is adjusted based on the active power delivery through the substation’s transformer, and another scheme when current compounding is combined with local active power curtailment controllers for large PV plants. The most important metrics used for comparison are voltage root mean square error (RMSE), the total voltage limit violation area, the percentage of curtailed PV energy, and the number of tap changes over the considered day. The simulations were carried out using Python and DIgSILENT PowerFactory.
The simulation results show that the MPC policy can perform better than the simple control schemes but only when exact knowledge of future profiles is available. In this case, the MPC results in lower voltage RMSE, smaller violation areas, and lower curtailment percentage values, at the expense of using more tap changes in all 4 test cases. In 3 of the 4 test cases, MPC was completely able to eliminate voltage limit violations, showing clearly the advantages of good quality forecasts on future disturbances. Since this exact knowledge about the near future fluctuations is quite ideal, more realistic MPC policies were also tested with no future knowledge and tightened voltage constraints. These simulations brought mixed results when compared with the simple schemes, performing better in terms of voltage RMSE, but worse in terms of the total voltage limit violation area.
In this thesis, a method is presented to assess the position of airports’ in a European intermodal network. This tool helps identify airports with the potential to facilitate intermodal travel in Europe. The service levels in both the air and the rail network, the physical integration between the modes, and the geographical location of airports are considered in different variables to assess the network. A Principle Component Analysis identifies the shared information between the different variables. The Principle Components are then clustered using an Agglomerative Hierarchical Clustering. With this clustering, airports are grouped based on their characteristics of intermodal factors, and different roles in an intermodal network can be identified. Comparing the descriptive statistics of each cluster helps assign qualitative labels to the cluster to classify the airports’ roles. After creating the benchmark with data from the current network situation, scenarios are constructed to assess the effects of implementing different policies regarding intermodality. Extending rail services and/or reducing short-haul flights are policies formed into scenarios in which the underlying data is modified. The change of clustering and classifications caused by the data modification helps identify potentially interesting airports in the network.
The results show that 20 to 30 of the 113 considered airports show a substantial role in intermodality. Also, the findings identify airports that change their position due to the scenario implementations and offer the potential for a significant role in an intermodal network. Finally, comparing the classifications in the different scenarios shows that the constructed scenarios can enable up to 14.3% extra passengers to travel intermodal.","Airport classification; Intermodality; Air/Rail integration; Hubs; Principle Component Analysis; Agglomerative Hierarchical Clustering; Europe","en","master thesis","","","","","","","","","","","","Transport, Infrastructure and Logistics","",""
"uuid:8151c738-b06e-4f9c-aec3-c814f8d61cf3","http://resolver.tudelft.nl/uuid:8151c738-b06e-4f9c-aec3-c814f8d61cf3","Numerical Analysis of Tonal Noise Emissions from Open and Shrouded Contra-Rotating Propellers","Barker, Evan (TU Delft Aerospace Engineering)","Ragni, D. (graduation committee); Zarri, A. (mentor); Delft University of Technology (degree granting institution)","2023","As market growth projections for Urban Air Mobility vehicles (UAMs) skyrocket, their presence in urban environments is likely to become increasingly prevalent, as will their noise. This creates a disturbance to both humans and wildlife, previously unaffected by aircraft noise. Further reinforcing the concern is the new multi-rotor designs, which introduce additional sources of noise.
Research on novel designs provides a limited understanding of the primary noise-generating mechanisms contributing to overall sound production. Among these innovative designs, complex geometries like open Contra-Rotating Propellers (CRP) and Shrouded Contra-Rotating Propellers (S-CRP) emerge. This study focuses on CRPs because they are anticipated to offer increased thrust with the same platform area, crucial for urban UAM operations. Additionally, shrouds are explored for their potential for increased thrust, acoustic shielding, and directivity manipulation, while also offering space for acoustic liners and increasing safety for ground operators.
The objective of this study is to isolate the aerodynamic and acoustic installation effects and identify the noise-generating mechanisms of the CRP and S-CRP configurations.
For this, the aerodynamics and acoustics of six propeller configurations are analyzed, including both the primary CRP and S-CRP geometries and sub-variants thereof. The exploration uses a hybrid numerical methodology, consisting of an aerodynamic flow solver based on the unsteady Reynolds-Averaged Navier-Stokes equations (uRANS) and a Finite Element Method (FEM) acoustic propagation solver. The latter generates acoustic sources from the aerodynamic solution using the source mode formalism.
This not only facilitates an aerodynamic understanding of the acoustic sources but can also detail near-field effects on acoustic propagation. While alternative methodologies achieving similar results necessitate high-fidelity simulations, the uRANS-FEM method can effectively capture aerodynamic and propagation effects within a moderate computational time. However, it also restricts analysis to tonal components of loading noise.
The CRP configuration showcased an improvement in efficiency metrics, marked by a 2.98% increase in FOM and a 57.53% increase in thrust per area, suggesting their higher efficiency and compactness compared to a single rotor. However, this came at the cost of increased noise levels, with amplifications ranging from 10 to 50 dB across various harmonics, attributed to the interaction of the contra-rotating blades. The study further noted a reduction in thrust for both the lead and rear propellers due to the interaction, particularly within the inner 75% radius of the rear propeller. A correlation between the azimuthal angle of the peak thrust and the angle of the highest noise generation was also observed.
When employing a shroud on a CRP, significant modifications in the performance of the shroud were not as anticipated in the literature. The shroud, while contributing to overall thrust, led to a considerable thrust reduction (over 54%) for both propellers due to separated flow. Acoustically, the shroud induced only a minor reduction in noise due to the aerodynamic effects, primarily due to decreased mean thrust. The dominant aerodynamic noise-generating mechanism in the S-CRP configuration is still the blade interaction...
Residents in the peripheral neighborhoods occupy open land in areas of varying environmental risk, susceptible to soil degradation, flooding, landslides, and health risks due to waste discharge. They cannot access publicly supplied water or sanitation and must rely on water cisterns, illegal connections or self-made sanitation disposal to acquire the necessary infrastructure to lead a healthy life. These risks, in addition to the future risks of climate change, disproportionally impact those living in informal settlements, due to their social vulnerability and socio-economic status.
Development-induced displacement of residents within informal settlements is enforced by the São Paulo municipal government, to permit the implementation of public infrastructure such as water lines, sanitation, drainage, street paving, and the removal of housing structures in at-risk areas. While the purpose of displacement contributes towards a positive outcome - upgrading neighborhoods with much-needed services, or rehousing residents to safer environments – the social impact of displacement is palpable. Forced displacement may move residents away from their sources of income and social networks, considerably impacting their mental well-being or exposing them to financial precarity. Readaptation to new neighborhoods or lifestyles can also be difficult for residents.
The project seeks to create a balance between social and climate resiliency to address the challenges of environmental risk and resettlement. The project proposes a new social housing system, built on the principles of clustering and the Radburn Plan, to achieve an urban design which integrates public space with rainwater flows, public infrastructure, and housing. The project location, Jardim Campinas in Grajaú, São Paulo, is used as a framework for the urban system to rehouse displaced residents from various communities onto one site. The socio-ecological design approach is implemented at each scale – urban plan, sector, cluster, and dwelling unit. The design aim is a renewal of the urban fabric, by building upon existing social and ecological networks to reinvigorate social connections and relationships between natural and built environment.","Global Housing; Social Housing; Sao Paulo; climate adaptation; Displacement; Risks; Flooding resilience; urban renewal; social resilience; Brazil","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Global Housing","","-23.77, -46.704"
"uuid:c2e93652-2bb7-4bba-9319-8dcdc5e68835","http://resolver.tudelft.nl/uuid:c2e93652-2bb7-4bba-9319-8dcdc5e68835","In the garden of Újlipótváros: Discovering the potential of an urban block","van Haastrecht, Benkt (TU Delft Architecture and the Built Environment)","Mejia Hernandez, J.A. (mentor); Jennen, P.H.M. (mentor); Delft University of Technology (degree granting institution)","2023","This graduation project investigates the potential of a site in the interior of an urban block in the 19th century neighborhood of Újlipótváros in the north of Budapest. The proposal is to convert this previously private and fenced off underused area into a cultural center within a large collective space. An open space divided in public and private naturally coming forth from the shape of the existing buildings. The cultural center is composed of 3 buildings each in a different relationship to the existing, a theatre build against a party wall, a courtyard of multipurpose spaces squeezed in between the existing buildings around a large existing tree and a free standing tower housing a gallery. All buildings are using the same structural logic, in a system of engineered wooden elements which can be installed without damaging the delicate site. The space in between is the connector of these buildings and is the core of the project, the potential of these inner courtyard blocks is to be a space for retreat and create an space away from the harsh and imposing environment that the surrounding city can be.","Budapest; Cultural Centre; Garden; Urban block; densification; Újlipótváros","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Methods and Analysis | Positions in Practice","","47.5162174907031, 19.05604218924858"
"uuid:ca6455b5-ff96-4db6-9447-56523d308207","http://resolver.tudelft.nl/uuid:ca6455b5-ff96-4db6-9447-56523d308207","Designing Dutch tunnel ventilation systems dominated by an uncertain fire scenario","van der Drift, Sophie (TU Delft Mechanical, Maritime and Materials Engineering)","Noel, L.F.P. (mentor); Delft University of Technology (degree granting institution)","2023","Adequate mechanical ventilation serves as the first and most important life-saving appliance during a tunnel fire. The most severe threat during a tunnel fire is the smoke. Most victims get incapacitated by the smoke, after which they decease from intoxication and/or suffocation. By means of mechanical ventilation, smoke-free escape routes via the central egress corridor are created. Two stages are considered in mechanical ventilation system design. The first stage involves the identification and positioning of jet fans to create a longitudinal ventilation system in the tunnel. The dangerous undesired reverse flow of smoke in the tunnel, back-layering, can be prevented by achieving a minimum critical air velocity. The second stage is a positive pressure establishment in the central egress corridor with respect to the tunnel. This is essential to prevent smoke flow from the tunnel into the central egress corridor through open escape doors. The tunnel ventilation performance is highly influenced by the position and heat release rate of the fire. Given the uncertainty concerning the fire, it is imperative that longitudinal ventilation is designed to consistently meet the back-layering constraint across all possible fire scenarios. For enhanced longitudinal ventilation reliability, jet fan placement at the tunnel entrance is preferable, while positive pressure ventilation benefits from a scattered jet fan layout.
A design approach based on the fundamentals of topology optimization is used to construct a systematic design method. To streamline the design of ventilation within the central egress corridor, optimizing longitudinal tunnel ventilation design while minimizing pressure downstream of the fire in the tunnel is advantageous. To prevent energy dissipation, a secondary objective specified as a penalization objective was introduced to promote the required distance between jet fans. This objective determines the placement of jet fans by considering the positioning of nearby jet fans within a specified distance, influenced by a penalization exponent. To address the fire related uncertainty, a scenario-based approach is applied. This method has the capacity to accommodate multiple fire scenarios simultaneously, where the designer can select the desired quantity.","Tunnel Fire Safety; Uncertainty; Topology Optimisation","en","master thesis","","","","","","","","2025-11-09","","","","Mechanical Engineering","",""
"uuid:e7f86dc3-4d94-4f4f-bb03-165b589cb37a","http://resolver.tudelft.nl/uuid:e7f86dc3-4d94-4f4f-bb03-165b589cb37a","Coastal Erosion and Mangrove Degradation in the Mekong Delta, Vietnam","de Klerk, Geert (TU Delft Civil Engineering & Geosciences); Stroeve, Axel (TU Delft Mechanical, Maritime and Materials Engineering); de Wit, Gillis (TU Delft Mechanical, Maritime and Materials Engineering); de Wit, Sam (TU Delft Civil Engineering & Geosciences)","Bogaard, T.A. (mentor); Hendrikse, H. (mentor); Truong Hong, S. (mentor); Delft University of Technology (degree granting institution)","2023","The Vietnamese Mekong Delta, a vital region in the country’s economy, faces the dual challenges of coastal erosion and mangrove degradation, which threaten its long-term sustainability and flood protection capabilities. This research focuses on the coastal area of the Bac Lieu province, characterized by severe erosion and degrading mangrove forests. The study investigates the applicability and potential impacts of hydraulic measures to decrease the net rate of coastal erosion, utilizing numerical modeling with Delft3D and a comprehensive socio-economic analysis. The research hypothesizes that the coastal erosion is partly driven by the placement of a sea-dike to protect aquaculture farms, initiating a positive feedback loop. This loop explains the relation between coastal erosion and mangrove degradation. The proposed hydraulic measures to interfere with this feedback loop are a porous detached breakwater, a shoreface nourishment and the removal of the existing sea-dike. The socio-economic analysis involves questionnaires for local residents, field investigations, and insights from experts in Ho Chi Minh City. While the questionnaires provide inconclusive results, the overall socio-economic impact of the nourishment and breakwater is deemed positive and worth further exploration, particularly in light of the critical role of mangroves in future flood protection. On the other hand it is concluded that the measure of removing the sea-dike will have a negative impact on the coastal area of Bac Lieu due to the intensive land-use and the lack of individual protection of the farms and villages. Therefore, this measure is not modelled. Numerical modeling with Delft3D assesses the hydraulic impact of the breakwater and nourishment on the heavily eroded and partially eroded coasts of Bac Lieu. Results indicate that the nourishment method exhibits a positive effect in reducing net erosion, especially in low energy conditions. Conversely, the porous breakwater shows minimal impact on cumulative erosion and sedimentation. Since this is against all expectations, the validity of the schematization of the porous breakwater is questioned. It is observed that the schematization does not grasp the complex behaviour of the breakwater and therefore it is concluded that Deft3D is not a suitable modelling tool for modelling a porous breakwater. The findings suggest that the nourishment method is a promising approach for reducing erosion in Bac Lieu, benefiting both the heavily and partially eroded coasts. To determine the best course of action for Bac Lieu, further research into the long-term effects and configurations of nourishment is recommended. Additionally, informing local inhabitants on the threats of relative sea-level rise and flood protection, and fostering consensus between the government and engineering agencies on the importance of protecting the Mekong Delta and its mangrove ecosystems are essential steps toward a more resilient future.","Mekong Delta; Coastal erosion; Mangroves; Breakwater; Nourishment; Building with Nature; Vietnam; MDP","en","student report","","","","","","","","","","","","Civil Engineering","","9.251556, 105.513649"
"uuid:feb24818-1ef3-4db7-9547-5d9a709051a1","http://resolver.tudelft.nl/uuid:feb24818-1ef3-4db7-9547-5d9a709051a1","Comparative feasibility study of a 30 MW disruptive floater solution with a 15 MW PivotBuoy and a benchmark 15 MW semi-submersible floater in the Bay of Biscay","Tijdeman, Dimitri (TU Delft Civil Engineering & Geosciences); Stevens, Jan (TU Delft Civil Engineering & Geosciences); Teuber, Lukas (TU Delft Civil Engineering & Geosciences); Lonissen, Mark (TU Delft Civil Engineering & Geosciences); Roeders, Niels (TU Delft Civil Engineering & Geosciences); Lip, Robbert (TU Delft Civil Engineering & Geosciences)","Lange, F.C. (mentor); Hoving, J.S. (graduation committee); Kirichek, Alex (graduation committee); Delft University of Technology (degree granting institution)","2023","This paper investigates the technical, life cycle, and economic feasibility of a 30 MW upscaled downwind turbine, comparing it to a 15 MW X1 Wind PivotBuoy downwind turbine and a benchmark 15 MW IEA Umaine VolturnUS-S upwind turbine in the 450 MW Sud de la Bretagne I wind farm site. The study is significant due to the rising energy demand, the potential for decreasing the levelized cost of energy with increased turbine size, and the optimized use of space. The size limit of current upwind turbine designs could be addressed using a downwind turbine solution.
The research is conducted by modelling the global dynamic response of the structure using OpenFAST and computing the natural frequencies and stresses using a finite element model. A lifecycle analysis is performed to identify potential pitfalls and bottlenecks by analysing the individual lifecycle phases. The economic feasibility is assessed by simulating the annual energy production using TOPFARM and utilizing structural analysis and lifecycle assessment to quantify capital, operational, and abandonment expenditures. Based on the annual energy production and the performance indicators the levelized cost of energy is calculated.
The findings indicate that while the global stability is within boundaries, the stress in members is too high with a simple scale-up of the proposed design. Bottlenecks are found in lifting operations and supply chain readiness. The levelized cost of energy and capital expenditure increased due to substructure self-weight, rendering the proposed 30 MW scale-up currently unfeasible when compared to the other two wind farms.
These findings are important as they demonstrate that the 15 MW X1 Wind PivotBuoy is not scalable without design changes. The levelized cost of energy does not decrease with an increased floater solution. The 15 MW X1 Wind PivotBuoy downwind turbine seems more economically viable, making it a more interesting option for future development.","Floating offshore wind turbine (FOWT); LCOE; Structural Analysis; Lifecycle Assessment; OpenFAST; Feasibility Study; MDP; Economic evaluation","en","student report","","","","","","","","","","","","Civil Engineering","",""
"uuid:ad10f6bc-da0e-446a-a8f2-7eeb5f61fabe","http://resolver.tudelft.nl/uuid:ad10f6bc-da0e-446a-a8f2-7eeb5f61fabe","Transitions: Reviving the historical legacy of swimming in the Danube by redesigning its waterfront","Rio Maior Alvarez e Serra, Mariana (TU Delft Architecture and the Built Environment)","Mejia Hernandez, J.A. (mentor); Havik, K.M. (graduation committee); Jennen, P.H.M. (graduation committee); Wilms Floet, W.W.L.M. (graduation committee); Delft University of Technology (degree granting institution)","2023","In a world that is becoming more virtual by the day, there is a longing for physicality that yearns to be fulfilled. This thesis explores the potential of architecture to evoke diverse behaviors and emotions, drawing from the idea that individual perceptions of space are subjective and influenced by the memories and knowledge ours bodies have absorbed from our unique lived experiences. With Budapest as a dynamic testing ground, the thesis focuses on activating the Danube waterfront.
The proposed project consists of a retreat that transitions the people from Budapest to the water fostering a more symbiotic relationship between the urban community and the river.
The project comprises two parts. The first is a private bathhouse facility, nestled within a once-concrete expanse in a park and sheltered within a public layer. The result is a building that outwardly serves the public, while inwardly housing an introvert private bathing facility. The second is a public floating structure, paying homage to the evocative reminiscences of old pontoon pools with a purpose of re-activating the historical legacy of swimming in the river. By sewing these two worlds together in one area, while bridging the community physically to the river, the proposal becomes a revitalisation of the waterfront.
The goal was to craft an architecture that delivers spaces capable of leaving a lasting impression on the mind and bodies of those who engage and experience them. Architecture is the set for life to happen, and we, as set designers, choreograph and orchestrate different scenarios and environments for different users to engage with - and the play plays out.
Objective: To obtain a robust control signal the study 1) investigated the relation between event-related desynchronization (ERD) and mechanical stretch reflex size in the flexor carpi radialis across four muscle pre-loads consisting of 0%, 5%, 25% and 40% of maximum voluntary contraction (MVC), 2) investigated the ability of three offline signal processing paradigms in distinguishing between periods of rest and activity using EEG data associated with motor execution and motor imagery, 3) built a pseudo-online signal processing paradigm to simulate real-time signal processing based on a single trial and a continuous data stream.
Method: Mechanical stretch perturbations were applied to the wrist under four percentages of MVC during motor execution and imagery conditions in six healthy subjects. The data anal- ysis encompassed signal processing techniques including pre- processing with a large Laplacian filter, feature extraction through autoregressive modelling (AR), power spectral density (PSD), or discrete wavelet transform (DWT), and classification using linear discriminant analysis (LDA).
Results: Mechanical stretch reflex sizes and ERD amplitude significantly increased with increasing percentage of MVC for motor execution trials. For motor imagery trials, no significant correlation was found between the stretch reflex size and ERD amplitude. The offline signal processing paradigms resulted in classification accuracies of 73.55% (PSD), 71.96% (DWT) and 57.13% (AR). The classification accuracies significantly increased with increasing percentage of MVC. The pseudo-online paradigm resulted in a mean classification accuracy of 51.38%.
Conclusions: The EEG-based BCI shows potential for enhancing the functional recovery of patients with motor disorders. The findings demonstrate that feature extraction methods PSD and DWT could effectively distinguish between periods of rest and activity in motor execution data. Nevertheless, for the intended application, including real-time processing based on single trial motor imagery data, BCI performance should be improved. Future research should focus on motor imagery EEG data encompassing motor imagery training and feedback on motor imagery performance.
Public stairs are positioned in the centre of the building, connecting the spaces under and above ground in one big continuous movement. The stairs come up inside a bay window with a view over the water just outside the main building volume, providing a scenic view of the water and connecting the park side to the waterfront. These stairs connect the park and the water as well as the industrial roughness of the lock space with the domestic intimacy of the gallery spaces and form a focal point in the building.
The facade is composed of panels made from offset glass blocks with wooden strips in between. For this facade I designed a new element which doesn't use mortar the connect the blocks and is demountable. Creating a translucent and transparent facade around the building which lets light through during the day and lights up at night.","Museum; Architecture; M HKA; Antwerp; glass block","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Interiors Buildings Cities","","51.2098275876965, 4.388755952738928"
"uuid:ba4bb2fc-e3d5-4029-bab2-1fddb9b249aa","http://resolver.tudelft.nl/uuid:ba4bb2fc-e3d5-4029-bab2-1fddb9b249aa","Design and control of an energy storage system for voltage flicker caused by clouds passing over photovoltaic systems","Wix, Lynrick (TU Delft Electrical Engineering, Mathematics and Computer Science)","Chandra Mouli, G.R. (mentor); van Voorden, A.M. (mentor); Fidder, Henk (mentor); Bauer, P. (graduation committee); Cvetkovic, M. (graduation committee); Delft University of Technology (degree granting institution)","2023","As more and more solar panels are installed on households, a problem arises when the power from the solar panels fluctuating throughout the day due to clouds passing over the solar panels. This in turn causes voltage flickers in the household, which can be visible/irritable to the human eye and damage appliances in the household. These voltage flickers can exceed limits set by the IEC standard 61000-3-7 or the visible flicker threshold on the Low Voltage (LV) network set by Qualtech [1]. This problem can be solved by making use of an Energy Storage System (ESS) which delivers active power in order to reduce and avoid the voltage fluctuations above the visible flicker threshold. In this report, a novel control algorithm is designed and implemented in two different ways to control the active power dispatch of the ESS. The main goal for the control algorithm is to reduce or avoid any visible voltage flickers from occurring and minimizing energy usage asmuch as possible in order to open the possibility for a Supercapacitor Energy Storage System (SESS) application in the future. For this, a power to energy ratio of higher than 70 is needed to achieve this. The primary control algorithm makes use of a moving average with a weight distribution that is optimised for smoothness and accuracy. Furthermore, extra layers of control was added to the control algorithm tominimize energy usage. The first implementation of the control algorithm, called power control, makes use of the Photovoltaic (PV) system output power to dispatch the appropriate amount of power from the ESS. The second implementation, called voltage control, makes use of the measured voltage at Point of Common Coupling (PCC) to dispatch the ESS power. Simulation results using pre-existing PV system data showed that the power control implementation was not able to fully eradicate all of the measured visible and annoying voltage flickers. The voltage control implementation was able to do so within the window of operation. Furthermore, simulation results showed that the energy usage from the control algorithm with a power control implementation uses 87% percent less energy than a control algorithm using conventional moving average. The energy usage from the control algorithm with a voltage control implementation uses 95% less energy than the conventional moving average control algorithm. Furthermore, the power to energy ratio of the control algorithm with a power control implementation was around 98.9 and with a voltage control implementation the power to energy ratio was around 190.2. This shows a clear implementation of a SESS in the future. Two different experimental setups were built and commissioned. The first setup having the Battery Energy Storage System (BESS) connected via an inverter on the same Alternating Current (AC) bus with the PV system. The second setup has the BESS connected on the same Direct Current (DC) bus with the PV system which is then connected to an inverter. Experiment results showed that the DC connected ESS experiment setup operating in power control mode had the best performance in terms of avoiding any visible voltage flickers from occurring. While the AC experimental setup and mode of operation (voltage and power control mode) did not operate properly due to the slow inverter response time. In terms of energy usage, both experimental setups had very low ESS energy usage. Although the results showed that power to energy ratio from both experimental setups using both power and voltage control did not exceed the set goal of 70 due to the limitations of both experimental setups. Finally, a conclusion based on the results is given with future work and as well as recommendations for the continuation on this research topic.","Voltage flicker; Photovoltaic systems; Energy storage systems; Control algorithm","en","master thesis","","","","","","","","2025-11-09","","","","Electrical Engineering | Electrical Power Engineering","",""
"uuid:747e2609-d469-4891-9701-c380a32a56ce","http://resolver.tudelft.nl/uuid:747e2609-d469-4891-9701-c380a32a56ce","The architectural challenge for physically disabled people: A research through the eyes of the physically disabled","Smorenburg, Sanne (TU Delft Architecture and the Built Environment)","van de Pas, R.R.J. (mentor); van Dooren, E.J.G.C. (graduation committee); van den Ban, R.R. (graduation committee); Bilow, M. (graduation committee); Delft University of Technology (degree granting institution)","2023","Currently people with physical disabilities do not have the option to be away from home for a short or longer period of time to relieve themselves from the medical situation at home. This creates a feeling that there is currently a building typology missing in society and forms a challenge to be further investigated. The objective is to gather knowledge about how physically disabled adults experience a place and in what way an architectural design can influence this in a positive way.
The focus for this research is on the physically disabled adults who live at home, are dependent on a wheelchair and daily care. The following main research question has been formulated to answer the problem statement above: “In what ways can architecture overcome the limitations that adults with physical disabilities face in daily life?” To be able to answer the main research question literature research was carried out and interviews were conducted among 5 participants. Two physically disabled, one informal caretaker and two medical professionals. All these participants are representative for both the interview as well as physically disabled adults in the home situation. The interview responses showed that there are 4 main important themes: spatial, social, independence and healthcare. This indicates that these themes are important for all participants. To conclude, the current built environment is missing an accessible building typology, a place that provides care without feeling so for both physically disabled adults as for able bodied people to spend time away from home.
Based on this my advice for follow-up research would be how to create awareness among architects about the life of physically disabled adults and how they can design for them?","Accessible architecture; Physical disability; Organic architecture","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Explorelab","",""
"uuid:5f87aca6-7966-4e12-92ea-cd4652fe929f","http://resolver.tudelft.nl/uuid:5f87aca6-7966-4e12-92ea-cd4652fe929f","Local Referendums for Urban Area Development: How public value conflicts contribute to the design and decision-making","den Hartog, Tessa (TU Delft Architecture and the Built Environment)","Ersoy, A. (mentor); Hobma, Fred (graduation committee); Delft University of Technology (degree granting institution)","2023","Local referendums are part of the local democracy and give citizens more direct discission power by their votes.The instrument can be used by the citizens to express their resistance towards the municipal plans or used by the municipality to consult their citizens about their plans. In the Netherlands, local referendums are despite their non-binding character still used nowadays. This instrument is also used for Urban Area Development plans, such as Amsterdam IJburg (1997) whereby citizens and special interest groups were concerned about the loss of nature in the area due to the large-scale land reclamation project. Another example is Arnhem Stadsblokken-Meinerswijk (2016), whereby a group of citizens expressed their concerns about building in the floodplains after the national policy ‘ruimte voor de rivier’ was introduced to make more space for the river instead of building in these areas. Until now, studies have been done about local referendums in general, the topics, about voting behaviour and the frequency of it. In addition, some research has been done on local referendums in urban development areas in Europe and America. However, studies about the added value of a local referendum in the Netherlands specifically about Urban Area Developments are missing. The report answers the following research question: How can a local referendum for urban area development contribute to the design and decision-making? The goal of the research is to gain a better understanding of the added value of a local referendum used for larger urban area development topics and how this influences design and decision-making. The research question will be answered by a literature review and the use of qualitative data, including interviews and archive documents on the case studies of IJburg and Stadsblokken-Meinerswijk. The research output is a list of recommendations for municipalities, on how the local referendum process can be improved specifically for UAD topics. The added value of local referendums for urban area development topics is mainly the contribution to legitimate decision-making. Also, citizens have more decision power next to the regular voting moments. In addition, the arguments on how this plan will support the city become clearer. Besides, the counter arguments and doubts about the plan are better heard than without a referendum. This research shows that conflicting public values, such as environmental values and development values, can by using a referendum create more awareness and could even turn into a positive outcome. However, from the analysis of the interviews, it became clear that there is a desire for an alternative form of referendums for UAD due to its more complex character wherein many interests are involved. The recommendations are mainly focused on the implementation of communication in the process. A participation process included in the referendum process is regarded as an essential part for municipalities and citizens to produce a coherent and feasible solution. This could even avoid conflict and thus corrective referendums.","Local Referendum; Urban Area Development; Design Change; Decision Making; Public Values; Public Value conflict; Nature","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","","51.98019110381755,5.891367844090252"
"uuid:d323a359-b91a-471f-bfde-52de9056c140","http://resolver.tudelft.nl/uuid:d323a359-b91a-471f-bfde-52de9056c140","Cyber Security and Resilience of Distributed Energy Resources Using Blockchain Technology at the Edge of the Smart Grid","Vian, Giacomo (TU Delft Electrical Engineering, Mathematics and Computer Science)","Stefanov, Alexandru (mentor); Palensky, P. (graduation committee); Qin, Z. (graduation committee); Semertzis, I. (graduation committee); Subramaniam Rajkumar, Vetrivel (graduation committee); Delft University of Technology (degree granting institution)","2023","The proliferation of Distributed Energy Resources (DERs) is decentralizing the power system, with more and more capacity installed in the distribution grids. Concurrently, the energy sector is embracing the Internet of Things (IoT) paradigm, resulting in the emergence of the Internet of Energy. However, this transformation introduces new concerns regarding cyber security. As the number of interconnected devices increases, the possible attack surface for malicious actors expands. Recognizing this challenge, researchers are investigating the potential cyber security benefits of applying blockchain in power systems. Blockchain offers some secure-by-design features, such as the immutability of the stored data, that can be leveraged to improve the cyber security of smart grids.
In this work, a blockchain-based application for the monitoring and control of a feeder in the Low-Voltage (LV) distribution grid is designed and tested. A smart contract is created and deployed in a private Ethereum blockchain utilizing the Proof of Authority (PoA) consensus mechanism. The blockchain application enhances the cyber security of the LV distribution system in three ways. First, it detects cyber attacks targeting DERs by comparing the setpoints received by prosumers with smart meter measurements. Second, it prevents cyber attacks by enabling the exchange of measurements and setpoints on-chain and by preventing unreliable prosumers from participating in the voltage regulation market. Third, it mitigates the effects of cyber attacks on the steady-state voltage magnitudes by enforcing a novel voltage regulation mechanism, in which a new metric is proposed to quantify the power-to-voltage relationship while considering the location of the power exchange.
The efficacy of the blockchain application is tested in a co-simulation environment together with a modeled LV distribution network, simulated in DigSILENT PowerFactory. The distribution network model is first used to assess the impact of cyber attacks manipulating the setpoints of Battery Energy Storage Systems (BESSs), which have been identified as the most critical DERs. The simulation results demonstrate that the considered cyber attacks can force the disconnection of inverters by causing violations of the acceptable steady-state voltage magnitudes. One of the scenarios demonstrates that a cyber attack targeting half of the BESSs in a feeder can lead to the collapse of the voltage, causing a local outage. Finally, the results of the co-simulation of the blockchain-based monitoring and control system, achieved by the Open Platform Communications Unified Architecture (OPC UA) communication protocol and by a series of clients managing the data streams, demonstrate its efficacy in detecting cyber attacks and mitigating their impact on the voltage magnitude across the feeder, thus reducing the number of disconnected DERs.
The research was carried out by investigating multiple gridshell node types. For each node type, the required fabrication processes were identified. Carbon data was gathered for all these processes, as well as for the materials making up the structure of the gridshell. The GWP of a gridshell structure was then calculated in Excel per node type, based on design variables. A parametric structural analysis script was made in Grasshopper using the plugin Karamba. This script provides the Excel sheet with the variables, allowing it to calculate, and optimize the GWP value. An existing gridshell made by Octatube was used as a case study throughout this research.
The research concludes that processing has a very limited impact on the GWP of a gridshell structure, with most of the GHG emissions being related to the materials. The choice for node type that is utilized, does influence the GWP significantly. The research has produced a ‘tool’ for assessing and/or optimizing the GWP of a gridshell structure. The tool consists of the Excel sheet and Grasshopper script, and has the potential to be very useful in early design stages to not only assess, but to help optimize the GWP of a gridshell structure.","Gridshell; Embodied carbon; GWP; Optimization","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Building Technology","",""
"uuid:17d690ca-159b-483d-b454-b8071043c603","http://resolver.tudelft.nl/uuid:17d690ca-159b-483d-b454-b8071043c603","PUBLIC + BUILDING, A design approach for the new Flemish Museum of Contemporary Art (VMHK) formerly known as M HKA","Manuel, Denzel (TU Delft Architecture and the Built Environment)","Pietsch, S. (mentor); Thomas, A.R. (mentor); Parravicini, M. (mentor); Sepulveda Carmona, D.A. (graduation committee); Rosbottom, D.J. (graduation committee); Pimlott, Mark (graduation committee); De Vocht, S. (graduation committee); Delft University of Technology (degree granting institution)","2023","The Flemish Museum of Contemporary Art (M HKA) is an institution strongly rooted in the existing fabric and socio-political framework of Antwerp South. The museum is located on the outskirts of the city, which has undergone consistent urban development and urban planning as the city grew into one of the most diverse metropolitan areas in Europe. In this development, the Antwerp Museum of Contemporary Art gradually sought to evolve with society and make way for a larger institutional purpose that pushed the museum agenda towards a more formal and generic interpretation of art spaces and how they are interpreted in light of the current zeitgeist.
In my final project, I revisit the meaning of art presentation in relation to cultural building by reconnecting with MKHA’s historic approach of capturing the essence of conserving and presenting contemporary art, an identity and genesis of an institution that has curated its growing collection between less conventional building layout and architectural fabric.
My design proposal is based on the sustainable idea and design language of reusing existing building tissue, specifically the former courthouse building which is assigned for the new developments of the M HKA or at the time entitled: Vlaams Museum voor Hedendaagse Kunst (VMHK). A building typology that exists of two prefabricated office towers that are connected by a low-rise structural addition and entrance.
Here, the practice of preserving and exhibiting art in an anti-museum condition becomes relevant again through the presence of existing structure and building layout, which, in resemblance to the former MHKA building, reinforces this familiar identity in which exhibiting art bears the title ‘symbiosis between’ anti-museum condition and institutional purpose.
An analytical uncertainty analysis assessment explores the propagation of uncertainties in the employed methods, highlighting the impact of several parameters on the combined uncertainty on the results. Additionally, an analytical expression for the amplitude-dependent errors in dynamic tests is derived, providing a useful tool to predict such nonlinear effects. A simulation study numerically verifies the results from the uncertainty analysis, as well as the solution equations used for the methods.
The methodology's validation is carried out through three consecutive test campaigns. The results demonstrate the capability of the static tests to consistently determine mass and CoG coordinates with limited uncertainties. The BFP method achieves satisfactory accuracy, although unexpected deviations from the numerical predictions are observed. As for the CP method, multiple factors exert a large influence on the accuracy of the final results. Among the ones analyzed in this work are: the length of the ropes, the radius of gyration of the body, and the accuracy in the frequency measurement. Moreover, in both dynamic tests the type of suspension system is found to have an effect on the accuracy of the measurements.
While not all the intended objectives have been achieved, this thesis contributes to the understanding of testing methodologies for rocket stages, and offers insights into achieving accurate and precise results with simple and cost-effective methods.","","en","master thesis","","","","","","","","2025-11-08","","","","Aerospace Engineering","",""
"uuid:6af29452-e644-4e77-a20c-a53bd9706f7b","http://resolver.tudelft.nl/uuid:6af29452-e644-4e77-a20c-a53bd9706f7b","Monolithic Spaces: Life in the shadows of fast urbanism","Al-Muraikhi, Reem (TU Delft Architecture and the Built Environment)","Alkan, A.S. (mentor); van der Meij, A.M.R. (mentor); Fokkinga, J.D. (mentor); Delft University of Technology (degree granting institution)","2023","","","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Transitional Territories","",""
"uuid:99e5c44d-03f7-4769-95c1-4a3e37e23bc7","http://resolver.tudelft.nl/uuid:99e5c44d-03f7-4769-95c1-4a3e37e23bc7","A-peel, A foraging enrichment device: Designing a foraging enrichment device for the primates of ARTIS zoo","Hack, Roos (TU Delft Industrial Design Engineering)","Schifferstein, Hendrik N.J. (graduation committee); Flint, Govert (mentor); Delft University of Technology (degree granting institution)","2023","► Introduction & Client | Over the last decade, there has been a notable increase of interest in discussions surrounding animal welfare, driven by a deeper understanding of the mental states of animals. This growing awareness has triggered a global push to improve laws and regulations in animal welfare, prompting zoos worldwide to increase their efforts in enhancing the quality of life for their captive animals.
Environmental enrichment has emerged as a crucial tool in increasing animal welfare, supported by studies showcasing its positive impact on reducing aggression and abnormal behaviour in captive animals. ARTIS Zoo actively applies environmental enrichment into its practices and collaborates with the University of Amsterdam to delve deeper into the behaviour and needs of their animals. Scientific research at ARTIS Zoo includes an ongoing exploration into whether primates can recognize time intervals.
► Project Scope | In an effort to further enhance the lives of their animals, ARTIS Zoo has joined forces with the faculty of Industrial Design Engineering of TU Delft to design a versatile device serving as both an enrichment tool and a research device. The project focusses on designing a feeding solution that mimics the natural foraging behaviour of the yellow cheeked gibbon and black crested macaque, taking into account both physical behaviour as well as cognitive abilities.
► Literature research | Literature research has delved deeper into animal welfare, environmental enrichment, and primate behaviour, resulting into important insights. Primates can forage efficiently because of their physical advantages over other animals while also using the WWW-memory (What, where and when). Primates use synchrony, temperature, solar cues and sensory cues to locate ripe fruit. Yellow cheeked gibbons forage in the high trees for fruit, while black crested macaques forage mostly on the ground between bushes and grass.
A vision has been shaped: The product should give the primates more autonomy over their feeding process while triggering the cognitive memory, decision making and problem solving abilities.
► Requirements | The design considerations for the device were carefully outlined, addressing the distinct needs of stakeholders:
Primate Usage: Concentrated on promoting foraging behaviour to reduce inactive periods.
Zookeeper Usage: Prioritizing a user-friendly design to maximize usability.
Researcher Usage: Enabling dual-purpose functionality for both enrichment and research, with remote control capabilities.
Safety Considerations: Ensuring material, assembly, and food safety through detailed specifications.
► Design | The final design (Figure 1.1) takes the form of a fruit, which needs to be peeled by primates to reveal food inside. The device closes automatically and can be locked and unlocked remotely. Iterative design improvements enhance user usability, material sturdiness, and food safety.
► User testing | User testing with gibbons at ARTIS Zoo showcases significant interest and interaction, supported by observational data indicating heightened engagement between gibbons, increased foraging activities, social behaviour and extended active periods in the presence of the device.
What is the current performance of the Đề Gi port and storm shelter system, and how can engineering methods be used to assess its potential for future growth within the broader context of sustainable socio-economic development?
The main research question is going to be supported by the following sub-questions:
How will the current logistic service network perform in the future vision as foreseen by the responsible authorities and how to verify it with an engineering responsible approach?
How to examine the accessibility of the port and storm shelter in the KND project, while ensuring a safe, robust, durable and effective system?
What are the consequences of the port and storm shelter upgrade on the logistical system and on the conditions in the waterway and what impact does this have on the Đề Gi area?
The main aim of this research is apply engineering methods to understand the system in order to assess its performance and put this in the context of the socio-economic development of the Đề Gi area and the Bình Định province. To achieve this, various research methods are used to analyse the current state of logistic service and nautical accessibility, to identify the bottlenecks in the systems. To include the aspect of incorporating the socio-economics in a broader context of the area, a stakeholder analysis is introduced. For the inland logistic services of the port, a qualitative 4(+1)-transport modelling model is established. For investigating the nautical accessibility, a comprehensive system analysis, including the topics of (1) climate, (2) hydrodynamics, (3) morphodynamics and (4) current and future conditions of the access channel, is conducted to provide insights into nautical accessibility challenges to enhance the safety, robustness, durable and effectiveness of the access channel.
To analyse the logistic service system in the area, field observation in combination with interviews are performed to have a concrete insight into the characteristic harbour patterns, traffic and transportation system and the current transportation network for the goods originating from the harbour. Additionally, various development plans and visions outlined by local authorities are reviewed to gain a comprehensive understanding of the area's future development. By evaluating the current state of the logistic service network alongside the region's development plans, the limitations within the network are identified. The primary bottlenecks in the logistic services system predominantly revolve around capacity and quality issues in the existing road network. Many of these limitations are expected to be addressed through the implementation of the local authorities' development visions. However, for a reliable conclusion, an engineering approach is necessary. To achieve this, a 4(+1)-step transport modelling, coupled with an All-Or-Nothing traffic assignment, is recommended. For the examination of the Đề Gi road network and traffic assignment, this approach provided an initial assessment of the intensity of each link within the study area relative to its corresponding capacity.
The second sub-question is addressed through an analysis and depth assessment, uncovering critical nautical accessibility bottlenecks. These include draught limitations and climate change impacts, potentially compromising safety, robustness, durability, and effectiveness. A depth assessment, considering different vessel types and water levels, provides insights into the current channel status. Safety is a major concern, especially for larger vessels during low water conditions, heightened by climate change. Robustness faces challenges due to sedimentation and storm vulnerabilities. Durability is threatened by changing climate conditions affecting sediment dynamics and storms. Effectiveness remains relatively stable, with 90\% accessibility for the expected future vessel fleet. These findings particularly point to the need for safety and durability measures, especially in light of future climate change predictions, necessitating climate-resilient design.
The third sub-question explores the port and storm shelter upgrade's impact on Đề Gi. Consequences include increased traffic and vessel intensity, on land and through the access channel, and a shift in vessel fleet mix, requiring improved infrastructure and access channel design. This enhances safety and, ultimately, drives socio-economic growth, education, and investment appeal in the Đề Gi area.
In the Đề Gi area, current transportation capacity falls short of future growth needs. Local authorities' development plans aim to resolve logistic service bottlenecks. Nautical accessibility is currently 90\% effective but not consistently safe. Climate change threatens its durability. Engineering models, like the 4(+1) step methodology and comprehensive system analysis in combination with a depth assessment, uncover transport and nautical accessibility challenges. These methods assess future impacts of the port and storm shelter upgrade, benefiting the Đề Gi area with socio-economic development, improved safety and new opportunities for the local community.","Vietnam; Đề Gi; Nautical Accessibility; Network Capacity; Port and Storm Shelter; Multidisciplinary Project","en","student report","","","","","","","","","","","","Civil Engineering","Multidisciplinary Project","14.127575, 109.206819"
"uuid:65e20c09-8e4f-4e51-9b40-984f4683157b","http://resolver.tudelft.nl/uuid:65e20c09-8e4f-4e51-9b40-984f4683157b","Development of the Experimental Design for the Validation of EEG Source Localization with fMRI: Application of a Haptic Robot to Identify Active Neuronal Ensembles","van Rooijen, Thom (TU Delft Mechanical, Maritime and Materials Engineering)","van der Helm, F.C.T. (mentor); Rassels, K. (graduation committee); van der Cruijssen, J. (graduation committee); van Rootselaar, A.F. (mentor); Delft University of Technology (degree granting institution)","2023","Various source localization algorithms exist to perform localization with High Density (HD)-ElectroEncephaloGraphy (EEG). However, validation of these EEG source localization algorithms is lacking. The current gold standard for source localization in the brain is functional Magnetic Resonance Imaging (fMRI) by calculating the difference in hemodynamic response to different stimuli. This study aims to validate HD-EEG source localization with fMRI using an MR compatible haptic robot. Participants performed several tasks with the robot to activate cortex patches and allow localization of source activity under various circumstances. These hypothesized patches are the somatosensory, motor and visual cortex. No comparison is made with fMRI due to time constraints. As no comparison could be made, we aim to validate the experimental methodology.
Activation of the somatosensory cortex is clearly visible. The visual cortex is often localized, but lacks power in some settings. Activity during the torque task can be localized, but not conclusively to the motor cortex. In all, the experiment was a success, as it was able to induce verifiable different brain states. Hypothesized task contrasts contained different activity distributions. Improvements can be made by generating a more detailed leadfield and by applying a linear manipulator","EEG; fMRI; Source Localization; Haptic; MR compatible Robot","en","master thesis","","","","","","","","","","","","Biomedical Engineering","4D EEG",""
"uuid:0e0f87a3-ac28-42ec-9579-117f84c359bb","http://resolver.tudelft.nl/uuid:0e0f87a3-ac28-42ec-9579-117f84c359bb","The Things We Have In common: The role of landscape architectural design in transforming landscape edges into commons","van Halsema, Jantine (TU Delft Architecture and the Built Environment)","de Wit, S.I. (mentor); Staničić, Aleksandar (graduation committee); Delft University of Technology (degree granting institution)","2023","Over the past decade, within many fields, there has been growing interest in thoughts and theories from the commons. In commons theory, the conceptualisation of something as a commons, is a way in which a common resource can be protected from enclosure, overexploitation or neglect by connecting it to a community which uses, manages and (re)produces the resource in a sustainable and socially just way, creating added value for the community as well. With the commons being originally connected to landscapes and natural resources, but the way we experience, use, and value landscapes has been changing, it is relevant to explore a contemporary relation between landscape and commons, and possibly using commons theory within landscape architecture as well.
This thesis explores the role of landscape architectural design in transforming landscapes into commons, with the particular focus on landscape edges. The study is focussed on the city of Den Helder which, being surrounded by the North sea and Wadden sea, has a valuable and intriguing land-water edge. However, this landscape as a resource is under threat of enclosure and neglect since the design and occupation of this edge limits its use by both humans and non-humans.
This research provides a framework for contemporary landscape commons consisting of ‘Landscape as Commons’ and ‘Commons in the Landscape’, and defines important factors and values to create landscape commons for both human and non-human communities. From a design exploration in the Wadden sea coast of Den Helder, general principles are derived to transform landscape edges into commons for both human and non-human species.
From the combined research can be concluded that ¬the landscape architectural design predominantly works on the level of resources, and has limited influence on the components of community and social practices. Through landscape architectural design, suitable conditions can be created for human and non-human communities to experience, make use of, appropriate and manage landscape edges as commons. This provides an important starting point for the transformation of landscape edges into commons, and provides a framework that balances different landscape values that need to be considered for landscapes to operate as commons.
To investigate the impact of moving objects in dynamic indoor environments, we first benchmark representative visual (dynamic) SLAM approaches, complemented by robustness assessments for preliminary insights. During this process, we adopt challenging sequences from GRADE, an ideal platform for simulating dynamic indoor scenes. Notably, the mainstream of dynamic SLAM methods employs detection or segmentation techniques as solutions. To explore the correlation between detector accuracy and overall SLAM performance, we integrate a series of trained YOLOv5 and Mask R-CNN models, each with varying accuracy levels, into dynamic SLAM systems. Subsequently, we evaluate these configurations on the TUM RGB-D sequences. Contrary to common intuition, the experiments indicate that more accurate object detectors do not necessarily lead to improved visual SLAM performance. This benchmarking process also illuminates several inherent limitations of current dynamic SLAM techniques, underscoring the imperative for further advancements.
Building upon these insights, we introduce DynaPix SLAM, an innovative visual SLAM system for dynamic indoor environments, where participation of visual cues (e.g., features) is weighted based on per-pixel motion probability values. Our approach consists of a semantic-free pixel-wise motion estimation module and an improved pose optimization process. In the first stage, our motion probability estimator employs a novel static background differencing method on both images and optical flows to identify moving regions. These probabilities are then incorporated into the map point selection and weighted bundle adjustment for backend optimization. We evaluate our DynaPix SLAM and its variant, DynaPix-D, in comparison with ORB-SLAM2 and DynaSLAM. These assessments are performed on both TUM RGB-D and GRADE sequences, with additional tests on the static versions of the GRADE ones. The results demonstrate that DynaPix SLAM consistently outperforms the other methods, showcasing reduced localization errors and longer tracking durations across various scenarios.
This thesis focuses on performance flight-testing methods for conventionally-configured helicopters, i.e., those that employ a single main rotor to generate lift and thrust, and a single tail rotor to counter-act the torque effect of the main rotor. More specifically, the scope of this research was limited to gas-turbine available power testing and power required for out of ground effect (OGE) hover and power required for level-flight (AKA cruise flight). The research was limited to the execution of up to ten flight test sorties on two types of helicopters; the Bell Jet-Ranger and the MBB BO-105 helicopters, both normally used for training at the National Test Pilot School (NTPS) in Mojave, California.
The goal of this thesis is to develop new and improved flight-test methods to rectify existing problems associated with the conventional methods. The conventional method for the maximum available power of a gas-turbine relies on three independent, single-variable polynomials that often yield poor prediction accuracy that sometimes even defy basic engineering concepts. The conventional method for OGE hover performance is overly simplified and neglects important blade non-linear effects. This results in inaccurate empirical models for hover performance representation. The conventional flight-test method for level-flight performance incorporates several drawbacks which not only make the execution of flight-test sorties inefficient and time consuming, but also compromise the level of accuracy achieved. This conventional level-flight method fails to specifically address non-linear effects such as blade-tip compressibility and drag-divergence that often results in inaccurate predictions, especially at high altitude and low air temperature conditions.
The research intended to develop new flight-test methods for the available power of a gas-turbine engine and for the power required for hover and level-flight. Both new methods are based on multivariable polynomial approach. The research was initiated with the development of a new method for the maximum available power of a gas-turbine engine. A novel method, referred to as the ‘Multivariable Polynomial Optimization under Constraints’ (MPOC), was developed. This method seeks for a third order multivariable polynomial to describe the engine output power as a function of the other three variables of the engine (compressor speed, temperature and fuel-flow). The maximum available engine power is realized by solving an optimization problem of maximization under constraints. For this optimization, the Karush-Khun-Tucker (KTT) method was used successfully. For the exemplary BO-105, the standard deviation of the output power estimation error was reduced from 13 hp (conventional method) to only 4.3 hp by using the proposed method. Expanding the flight-test data base to include seven different engines reveals that the multivariable polynomials approach of the proposed method performed much better with all seven engines, as compared to the conventional single-variable approach. The maximum average prediction error was only 0.2% as compared to a maximum average prediction error of 1.15%, yielded by the conventional method.
The research effort conducted for the OGE hover performance was concluded successfully with the development of the novel “Corrected Variables Screening using Dimensionality Reduction” (CVSDR) method for hover performance. This novel method combines fundamental dimensional analysis to generate a list of candidate corrected-variables (CVs) to represent the hover performance problem, then screens for the most essential ones by means of dimensionality reduction, implemented by singular-value-decomposition (SVD). This phase of the research was executed with four sorties on the Bell Jet-Ranger helicopter and produced a total of five conclusions. The most significant conclusion was that power predictions of the CVSDR method were 1.9 times more accurate than the conventional method. At the 95% confidence level, the CVSDR method deviated by an average of only 0.9 hp (0.3% of the maximum continuous power of the example helicopter) from the actual power required to hover, whereas power predictions from the conventional method deviated by an average of 1.7 hp.
The final phase of the research concentrated on developing a new flight-test method for the level-flight regime. This effort spanned over five distinct sorties using the BO-105 helicopter. Similar concepts used for the hover performance testing were expanded and adapted for level-flight performance flight testing. The CVSDR method for level flight performance can be regarded (abstractly) as an expansion of the CVSDR method for OGE hover into a higher dimensional space. This phase of the research was aimed at addressing five research questions and yielded ten conclusions. The top three conclusions were that (1) the power predictions accuracy achieved using the CVSDR method for level-flight was nearly 21% better (on average and at the 95% confidence level), as compared to the prediction accuracy yielded from the conventional method. (2) the CVSDR method made planning and execution of flight-test sorties more efficient and time conserving. It is estimated to reduce flight-time for data gathering by at-least 60%, and (3) the CVSDR method is not restricted by the high-speed approximation, hence is also appropriate for the low-airspeed regime, and can potentially bridge the empirical modelling gap between the hover and level-flight regimes.
The novel flight-test methods developed within this research (the MPOC for the available power of a gas-turbine engine and the CVSDR for OGE hover and level-flight performance) are recommended to be used by the helicopter flight-testing community, as they were shown to increase accuracy and promote execution efficiency.
This thesis produced six recommendations concerning possible future expansion of the work already done during the current research. These include an expansion of the CVSDR method into more areas of performance testing like vertical and forward flight climb, partial power and unpowered descent, etc. Another continued research recommendation relates to the applicability and efficiency of the CVSDR method to relevant vertical-lift aircraft that combine both RW and FW characteristics. It is also recommended that continued research look into the potential and feasibility of employing the CVSDR method for empirical modelling used by Health and Usage Monitoring Systems (HUMS) installed in helicopters.
In this research, various design strategies were analyzed. Based on the findings, a design strategy is developed to design and analyze Moonshot. A combination of Ulstein Design and Solution B.V.’s Controlled Innovation process and Blended Design were used and extended to develop this new concept. First, the important functions and design aspects of the design were established using Controlled Innovation. Blended Design was then used to create a design space of the design configurations and to explore multiple market scenarios to establish optimal ship parameters for further development. As part of the research, the existing design process and model were modularized and new features were developed to suit wind turbines, assess seakeeping behavior, and explore the design space of the future wind turbine installation vessel.
The results of this research aim to elucidate optimal design parameters across certain market scenarios. Results show how optimizing the design for financial performance, seakeeping behavior, or a combination of the two, influences the optimal design point. With the optimal design ranges, the initial design parameters for the next stage in the design of Moonshot are established. Finally, Blended Design is used to benchmark Moonshot against existing wind turbine installation solutions to assess its performance. A version of Moonshot is developed as a direct competitor for the largest jack-up design available, the NG-20000X. Benchmarking with the jack-up, an SSCV, and Huisman’s WIV concept showed that Moonshot would be a more efficient solution, capable of installing a larger number of turbines per year at a considerably lower cost per megawatt compared to the other solutions.
In summary, this research concludes Moonshot as an innovative concept to address the evolving challenges of offshore wind turbine installation. By combining innovative design strategies, extensive assessment, and optimization, Moonshot emerges as a promising contender in the quest for effective and cost-efficient installation solutions for offshore wind.","Offshore wind turbine installation; Early stage design; Complex design methodologies; Ship design; Concept development; Design Space exploration; Financial performance; Seakeeping performance","en","master thesis","","","","","","","","","","","","Marine Technology | Ship Design","",""
"uuid:cc9e67b4-6bde-4114-97c0-43b11b4a48ef","http://resolver.tudelft.nl/uuid:cc9e67b4-6bde-4114-97c0-43b11b4a48ef","Auralisation of Modelled Wind Turbine Noise for Psychoacoustic Listening Experiments: Development and Validation of the Wind Turbine Auralisation Tool WinTAur","Pockelé, Josephine (TU Delft Aerospace Engineering)","Merino Martinez, R. (mentor); Bertagnolio, Franck (graduation committee); Fischer, Andreas (graduation committee); Ragni, D. (graduation committee); Schmehl, R. (graduation committee); Delft University of Technology (degree granting institution); Technical University of Denmark (degree granting institution)","2023","Wind turbine noise is one of the grand challenges in the public acceptance of onshore wind farm projects. The field of psychoacoustics identifies the auralisation of wind turbine noise as a link between technical design and annoyance estimation. There is currently limited work on the auralisation of wind turbine noise, and none targets an application in psychoacoustic research.
This work investigates the auralisation of the aeroacoustics output of DTU's HAWC2 for use in annoyance estimation. A Gaussian beam tracing approach propagates the frequency domain output to observer locations. The resulting spectrograms are converted into sound signals by applying random phase and the inverse short-time Fourier transform. This work includes a binaural rendering module to enable future VR applications. The methodology's implementation results in the Wind Turbine Auralisation tool, WinTAur.
The noise signal output of WinTAur is validated using the HAWC2 model of a stall-controlled NTK 500/41 wind turbine and corresponding acoustic field measurements. Psychoacoustic sound quality metrics show significant differences between the auralised and measured noise. In the overall psychoacoustic annoyance metric, these differences mainly depend on the observer's position around the turbine. All metrics show this directionality dependence, while the loudness, sharpness and tonality metrics also indicate a dependence on wind speed. Differences in fluctuation strength show a minor dependence on the simulation case but are difficult to relate to a specific simulation parameter.
Spectral analysis of the simulation output samples reflects the limitations of HAWC2, demonstrating that it is the primary source of discrepancy. The analysis especially highlights the inaccurate prediction of the directionality and stall noise of the HAWC2 code. The choice of ground type is another probable source of discrepancy, as it does not accurately represent the measurement setup.
A subjective listening experiment demonstrates the significance of these discrepancies in human perception with generally high difference ratings between the simulated and recorded noise. The results illustrate a dependence on wind speed and the position around the turbine. These dependencies match well with the findings from the numerical validation.\\
Future work should focus on a sensitivity analysis of WinTAur since the case-independent parameters may be additional sources of discrepancy. Another recommendation is to investigate the unveiled errors in the underlying methodology. Lastly, better propagation modelling concerning the wind turbine wake and turbulence should be part of future wind turbine noise modelling.
Overall, using modelled wind turbine noise for the auralisation in psychoacoustic research has shown promising results. Validation with sound quality metrics provides good insights into the discrepancies found in subjective listening experiments. Eliminating the existing discrepancies through modelling improvements will allow this work to be applied in a fully modelled approach to estimate wind turbine noise annoyance.","Wind Energy; Auralisation; Noise; Wind Turbine Noise; Renewable energy; Acoustics","en","master thesis","","","","","","","","","","","","European Wind Energy Masters (EWEM) | Rotor Design Track","",""
"uuid:5d602f53-1fb3-41a0-81dd-28ffd0d20787","http://resolver.tudelft.nl/uuid:5d602f53-1fb3-41a0-81dd-28ffd0d20787","Online state migration in modern stream processing engines","Veneti, Theodoros (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Web Information Systems)","Katsifodimos, A (mentor); Decouchant, Jérémie (graduation committee); Delft University of Technology (degree granting institution)","2023","Stream Processing Engines (SPEs) are called upon to help solve problems around big and volatile data, while satisfying the needs for near real-time processing. In order for such systems to be considered effective solutions to such problems at scale, efficient elasticity and non dataflow-disturbing reconfiguration operations within are a necessity. To that end, we visit the problem of online state migration, as the biggest obstacle in achieving such a desired behaviour, in SPEs that support stateful functions. We make an attempt to formally define the problem and associated sub-tasks, compare existing solutions and identify key aspects, as well as design and implement our own solution. Our testing shows that the lazy-fetch online state migration process proposed, outperforms a simple baseline state migration design by orders of magnitude in end-to-end latency observed, scales much better under increased workloads and relies on consistent design concepts to claim exactly-once semantics.","SPE; stream processing engines; state migration; online state migration; fetch on demand; reconfiguration","en","master thesis","","","","","","","","","","","","Computer Science | Data Science and Technology","",""
"uuid:14bf31b5-0d8f-44df-8da7-5fa99c0ae452","http://resolver.tudelft.nl/uuid:14bf31b5-0d8f-44df-8da7-5fa99c0ae452","On design of tunable leaky waveguide antennas for a large format lens based focal plane array with wide scanning capabilities","Zhang, Muhan (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Tera-Hertz Sensing)","Llombart, Nuria (mentor); Dabironezare, Shahab Oddin (mentor); Kooij, B.J. (graduation committee); Delft University of Technology (degree granting institution)","2023","Recently, there has been an increasing demand for security in public places. As a result, non-destructive and fast millimetre-wave and submillimetre-wave imaging systems have gained more and more attention.
This project is based on Concealed Objects Stand-off Real-Time Imaging for Security (CONSORTIS), which is a European next-generation airport security imaging radar system published in 2017. In this project, we will discuss the design of the lens antenna illuminated by a leaky wave waveguide antenna for a large format focal plane array with wide scanning capabilities in three typical cases. The Coherent Fourier Optics (CFO) and leaky wave antenna design methodologies are used in this project. The system will be analysed in reception mode and then validated in transmission mode. We have a very promising performance with an aperture efficiency of about 80% in the centre and 47% at the edge of the array with a shaped top and AR coating. The directivity of the antenna at the edge is about 50.2 dB. And the scan loss is about -2.3 dB, which means it can scan about 10,000 beams in total.
The research explores the feasibility of adopting FRP in the main load-carrying system of pedestrian bridges and develops a framework for the concurrent geometry and material architectural optimisation of said structures. The study aims to achieve significant cost- and carbon footprint reductions in
monocoque FRP bridges by employing a numerical optimisation approach.
The optimisation tool utilizes the computer-aided geometric design (CAGD) software Rhino® and its parametric interface, Grasshopper®, to concurrently optimise the shape and material architecture of the bridges. Through the use of genetic algorithms, the framework overcomes FRP’s poor stiffness and
stability, and maximizes its unique advantages, including lightweight and high-strength properties, enabling free-form designs. This feat is achieved by implementing hybrid sandwich panels, comprising glass fibre-reinforced polymer (GFRP) and carbon fibre-reinforced polymer (CFRP) face sheets.
Satisfactory stiffness is ensured by defining deflection constraints, whereas constraints on the fundamental frequency and critical buckling load factor ensure adequate stability.
The research demonstrates promising results, showing potential cost reductions of up to 17% and carbon footprint reductions of up to 27.4% compared to a real case design carried out by FiReCo. However, certain limitations and areas for improvement are acknowledged, including the required run-time and the complexity of the solution space. Suggestions for enhancing the framework’s efficiency are proposed, including implementing orthotropic failure criteria and reducing the solution space through adjustments to ply thicknesses and foam core configurations.
Overall, the developed optimisation tool provides valuable insights and serves as a valuable resource for researchers and practitioners seeking sustainable and economically viable bridge designs. By embracing innovative solutions and eco-friendly materials, this study contributes to global efforts towards carbon neutrality and sustainable infrastructure development in the built environment.
electron microscopy (SEM), and profilometry. Post-test analysis was carried out by optical microscopy and X-ray Photoelectron Spectroscopy (XPS). An intensification of surface cracks was observed for the K2CO3-rich sample before testing and its initial discharge capacity is 27 mAh/g less than a sample without pore former, but passivated later than the pristine sample in the full cell. Amongst the additives, the highest cycle of 100% capacity retention was marked at cycle 41 for FeS and for Bi2S3 at cycle 29 in the full cell, both showing 100% retention in the half cell up to 36 cycles. FeS might benefit from its readily available soluble reservoir of S2− ions. Bi2O3 showed the lowest capacity retention which might be explained by low conductivity, low solubility and/or lack of beneficial role of S2− ions. However, the additive Bi2O3 showed great reversibility of discharge products in the CV, confirmed by the lower O1s peaks and the lower respective Fe2O3 and FeOOH peak in XPS spectra. The pristine sample showed in the CV over the cycles increased current density and slope near the HER potential, with low reversibility. Apart from Bi2O3 and ZnS, the pristine sample showed lower capacity retention than FeS and Bi2S3, confirming the effective working of these additives. This systematic study portrays a good starting point for further studying porosity and additive effects on the electrochemical behaviour in hot-pressed anodes for the upcoming Iron-Air battery. Improvements can be assigned to cell design, electrolyte control and further detailed porosity characterization. Another type of current collector
might withstand higher current densities and anode thickness reduction can lead to higher discharge capacities over its lifespan.","","en","master thesis","","","","","","","","2025-11-07","","","","Materials Science and Engineering","",""
"uuid:5e7f939a-f746-488f-b57d-0531c3192d9a","http://resolver.tudelft.nl/uuid:5e7f939a-f746-488f-b57d-0531c3192d9a","Future scenarios for sustainable flat glass use: An exploration of material flows, aesthetics, and policy","Snip, Felicia (TU Delft Industrial Design Engineering)","Tempelman, E. (mentor); Sprecher, B. (mentor); Delft University of Technology (degree granting institution)","2023","Float glass is a largely unexplored material flow in the context of circularity. As the Dutch government wants construction to be fully circular by 2050, new ways have to be found to deal with float glass. Five scenarios for sustainable glass handling are discussed: what would happen if all available secondary windows would be recycled, remanufactured, reused, repaired, or if glass use would be reduced? The effects on material demand, energy use, value chain processes, and product are explored and compared. Finally, policy options are proposed to stimulate these sustainable strategies.","","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:6548d010-ba2a-4e4a-8aca-cc9ae3b4e2c4","http://resolver.tudelft.nl/uuid:6548d010-ba2a-4e4a-8aca-cc9ae3b4e2c4","Local ownership: Does It Matter?: A Cross-Case Institutional Analysis of 14 Onshore Wind Farms in the Netherlands","Brouwer, Bas (TU Delft Electrical Engineering, Mathematics and Computer Science)","Hoppe, T. (mentor); van Bergem, R. (mentor); Renes, Sander (graduation committee); Kamp, L.M. (graduation committee); Delft University of Technology (degree granting institution)","2023","Wind energy is deemed important in the Netherlands in sustainable energy transitions. While Commercial Wind Energy Project Developers (CWEPDs) bring professionalism, Local Energy Cooperatives (LECs) promote local renewable initiatives. The Dutch Klimaatakkoord aims for 50% community-owned renewable electricity, but real-world implementation of community involvement is unclear. The Institutional Analysis and Development (IAD) framework helps understand 'rules-in-use' for decision-making. This study explores how LECs and CWEPDs interact with these rules, focusing on Dutch onshore wind farm projects. Using 14 case studies, the research compares organisational forms in project outcomes, employing interviews and written sources for data collection and statistical testing and QCA for analysis. Key findings include LECs completing projects faster and with fewer objections than CWEPDs and the importance of transparent information sharing. The study suggests policy and development implications, highlighting the need for more inclusive and transparent decision-making in wind energy projects.","Wind Energy; Netherlands; Onshore Wind Farms; Commercial Wind Energy Project Developers (CWEPDs); Local Energy Cooperatives (LECs); Local Ownership; Institutional Analysis and Development (IAD); Qualitatative Comparative Analysis (QCA); Stakeholder Involvement; Decision-Making Processes","en","master thesis","","","","","","","","","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:323f5836-e73a-4bab-83bb-045803f25ffb","http://resolver.tudelft.nl/uuid:323f5836-e73a-4bab-83bb-045803f25ffb","Malleable Kernel Interpolation for Scalable Structured Gaussian Process","Ban, Hanyuan (TU Delft Electrical Engineering, Mathematics and Computer Science)","Rajan, R.T. (mentor); Fioranelli, F. (graduation committee); Giovanardi, Bianca (graduation committee); Delft University of Technology (degree granting institution)","2023","Gaussian process regression (GPR), a potent non-parametric data modeling tool, has gained attention but is hindered by its high com- putational load. State-of-the-art low-rank approximations like struc- tured kernel interpolation (SKI)-based methods offer efficiency, yet lack a strategy for determining the number of grid points, a pivotal factor impacting accuracy and efficiency. In this thesis, we tackle this challenge.
We explore existing low-rank approximations that facilitates the computation, dissecting their strengths and limitations, particularly SKI-based methods. Subsequently, we introduce a novel approxima- tion framework, MKISSGP, which dynamically adjusts grid points us- ing a new hyperparameter of the model: density, according to changes in the kernel hyperparameters in each training iteration.
MKISSGP exhibited consistent error levels in the reconstruction of the kernel matrix, irrespective of changes in hyperparameters. This robust performance forms the bedrock for achieving accurate approx- imations of kernel matrix-related terms. When employing our rec- ommended density value (i.e., 2.7), MKISSGP achieved a comparable level of precision to that of precise GPR, while requiring only 52% of the time compared to the current state-of-the-art method.","Gaussian process regression; Low-rank approximation; Structured kernel interpolation; Grid points; Density","en","master thesis","","","","","","","","2024-05-07","","","","Electrical Engineering","",""
"uuid:18cde7be-bc64-4dcf-8c05-2997b274ba21","http://resolver.tudelft.nl/uuid:18cde7be-bc64-4dcf-8c05-2997b274ba21","TAKE [A] PART: Urban Design of Physical Public Spaces from a Social Perspective","Boersma, Charlotte (TU Delft Architecture and the Built Environment; TU Delft Urbanism)","Newton, C.E.L. (mentor); Balz, Verena Elisabeth (graduation committee); Korthals Altes, W.K. (graduation committee); Delft University of Technology (degree granting institution)","2023","Social cohesion is perceived to be under pressure in the Netherlands, especially in its larger cities. The Covid-19 pandemic has reinforced and deepened the socio-spatial divide between vulnerable urban areas and the rest of the city, which not only affects the residents of the area and of the city, but also starts to affect the cohesion of the society as a whole. In light of the large scale spatial transitions that will also need to take place in these vulnerable urban areas, the Dutch government has issued the National Programme for Liveability and Safety, a long term, integrated and multidisciplinary urban regeneration approach to tackle the liveability, safety and social issues within the vulnerable urban areas. To achieve the overall improvement of the quality of life of the residents, it is stated in the Programme that interventions in the spatial domain should reinforce policy objectives in the social domain and vice versa. The objective of this graduation project is to explore to what extent urban design of physical public spaces in urban areas can facilitate the formation of social cohesion. To do this, literature research was conducted to define social cohesion, and to translate the concept to the local community level into specific urban design objectives. For this, the Social Cohesion Radar of the Bertelsmann Stiftung was taken apart and operationalised into requirements and a description of the ideal situation. From this, it was concluded that the design objectives consist of certain types of social interactions with specific characteristics. Furthermore, using relevant theories from environmental psychology and sociology, it was researched how the environment affects human behaviour. Combined with urban design theories the findings from the theoretical exploration and the operationalisation were used to develop a framework to analyse a physical space from the lens of social cohesion. In this analytical framework, the central point through which urban design interventions connect to social cohesion is through social interactions. Through the design of specific elements the defined social interactions could be directly facilitated, or would be facilitated via the improvement of characteristics of the space. The type of space that is analysed sets the expectations for the interactions that are likely to occur, and sets expectations for the characteristics and elements to be found there. For the implementation of the framework a guideline was developed, as well as an overview of typical settings to be found in Dutch urban areas, and a set of possible design interventions for social cohesion. The use of the framework to analyse a physical public space in an urban area should provide an urban designer with a decent understanding of the potential of the space to facilitate social cohesion, and provide the designer with possible spatial improvements. The framework provides the urban designer with an instrument to develop explicit and specific hypotheses regarding the facilitation of social cohesion through urban design.","Social Cohesion Radar; Physical Public Space; Urban Design; Behaviour Settings; Social interactions","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Urbanism","",""
"uuid:ddc4a5d7-190d-4135-8768-7c63a1ce3de9","http://resolver.tudelft.nl/uuid:ddc4a5d7-190d-4135-8768-7c63a1ce3de9","Living With Data","Bakker, Yannick (TU Delft Architecture and the Built Environment)","van de Pas, R.R.J. (mentor); de Krieger, J. (mentor); Warries, G.Y. (mentor); Lub, M. (graduation committee); Delft University of Technology (degree granting institution)","2023","The research and design hypothesize how data centers can complement the urban environment rather than make a negative impact, both environmentally and spatially. Data centers consume and produce a variety of valuable flows, ranging from electricity, cooling/heating and water use. The aim of the research is to discover whether it is possible to create synergy between these flows in a mixed-use building that contains both data center, residential and greenhouse program. All flows for the different programs are analyzed, quantified and visualized. Through the findings, the flows and programs are linked together. This in turn creates possibilities to redesign and optimize the processes of these flows and reduce the amount of resources needed (input) while at the same time reducing waste (output). Based on the research, a mixed-use building is proposed for the Sluisbuurt neighborhood in Amsterdam, The Netherlands. Both a data center, residential program, greenhouse program and a diverse public program are combined.","architecture; data center; energy; water; metabolic flux analysis; housing; greenhouse; amsterdam; sluisbuurt","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences","",""
"uuid:b91c91e6-6250-4eba-ab44-8ab486176a1d","http://resolver.tudelft.nl/uuid:b91c91e6-6250-4eba-ab44-8ab486176a1d","Investigating the anion doping effect on the conductivity and stability of cost-effective halide solid electrolytes","Bouillez, Matéo (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft RST/Storage of Electrochemical Energy)","Cheng, Z. (mentor); Wagemaker, M. (mentor); Wang, Xuehang (graduation committee); Eijt, S.W.H. (graduation committee); Delft University of Technology (degree granting institution)","2023","Batteries play a vital role in the ongoing energy transition, driving the demand for safer, energy denser and higher performing energy storage solutions. This has propelled research of solid-state batteries. Halide electrolytes, with high ionic conductivities and high oxidation stabilities, have attracted tremendous interest. Currently, the main challenge is that most promising halide solid electrolytes are reliant on expensive and scarce metals, hindering their application at an industrial scale. Therefore, it is of great significance to develop cost-effective halide electrolytes. Zr-based electrolytes show great promise due to their cost-effectiveness (ZrCl4 = 12.5 USD/kg) and high abundance in the earth's crust (165 mg/kg). However, so far their conductivity have been unsatisfactory, falling below 1 mS/cm. Anion doping with elements like Cl, Br, I, and O has demonstrated to be effective in improving the conductivities of sulfide solid electrolyte. In this work, the O-doping effect is investigated in Zr-based halide solid electrolytes with Li2xZrCl4Ox. By using various analysis techniques such as X-ray diffraction, electrochemical impedance spectroscopy, and cyclic voltammetry, this study explores the relationship between compositions, conductivities, and phases within the Li2xZrCl4Ox system. The findings reveal that, for each Zr-based oxyhalide composition, varying ball milling times result in different phases, with the most amorphous phase displaying the highest ionic conductivity. Specifically, for x = 1, Li2ZrCl4O reaches 1.60 mS/cm after 17.2 hours of ball milling, characterized by a structure featuring 61% amorphous content. Additionally, it demonstrates good performance as an all-solid-state battery with LiNi0.8Mn0.1Co0.1O2/ Li2ZrCl4O/ Li6PS5Cl/Li-In, achieving an initial capacity of 125.6 mAh/g at 0.5C and retaining 67.47% capacity after 1000 cycles. Moreover, the impact of I-doping is further explored in Li3YCl3Br3-xIx, another cost-effective halide solid electrolyte (YCl3 = 330 USD/kg and 33 mg/kg). The Li3YCl3Br3-xIx electrolyte displays tunable conductivity and stability characteristics with an excellent conductivity of 3.55 mS/cm for x = 1 compared to 1.94 mS/cm for x = 0 but with a trade-off in oxidation potential of 3.474 V to 3.59 V. This study provides insights into novel cost-effective electrolytes and exhibits the potential of anion doping in enhancing and tuning both conductivity and stability. These electrolytes hold a serious potential as a solid electrolyte in solid-state batteries.","Li-ion battery; Solid state battery; Halide electrolytes; Cost-effective; Energy Storage","en","master thesis","","","","","","","","2025-11-07","","","","Electrical Engineering | Sustainable Energy Technology","",""
"uuid:c96c4ed5-2a03-4145-a011-0b16446457b5","http://resolver.tudelft.nl/uuid:c96c4ed5-2a03-4145-a011-0b16446457b5","Design of a compliant locally resonant metamaterial unit cell for low-frequency vibration attenuation","Mian, Osama (TU Delft Mechanical, Maritime and Materials Engineering)","Hunt, A. (mentor); Hassan HosseinNia, S. (mentor); Herder, J.L. (graduation committee); Delft University of Technology (degree granting institution)","2023","Vibrations have been studied in various engineering fields due to their detrimental and even destructive effects on structures. Suppressing low-frequency vibrations has been a research challenge for decades and is mostly achieved by implementing active vibration control techniques. In the last two decades, the emergence of locally resonant metamaterials has sparked the interest of several researchers to create passive vibration attenuation structures as an alternative to active vibration-suppressing techniques. This research focuses on developing a local resonator-based unit cell that is able to attenuate vibrations at a wide range of low frequencies. A literature research is performed on the state-of-the-art in the field of locally resonant metamaterials and their wave-suppressing properties. Several wave directions and types are considered,
while low-frequency vibration attenuating structures are actively discussed. A comparative study is done on current local resonator-based structures from which a novel compliant metamaterial is proposed that can suppress a wide range of low-frequency vibrations. The proposed novel compliant negative stiffness local resonator (NSLR) unit cell has the ability to attenuate low-frequency vibrations at a wide range of frequencies while exhibiting a large load-bearing capacity. This concept is based on compliant mechanisms and relies on the snap-through motion of buckled beams for its negative stiffness, whereas folded beams are used in the design as load-bearing positive stiffness components. The stiffness and load-bearing capacity of the unit cell is determined by analytical and FEM-based numerical models, while dispersion relations and transmissibility functions are used to identify the dynamic vibration attenuation behavior. A prototype is produced by FDM additive manufacturing and tested in an experimental setup to verify the load-bearing capacity. An analytical and numerical load-bearing capacity between 100 N and 102 N, and 111 N to 115 are established, respectively, with an effective vibration
attenuation displacement range of 2.5 mm. The FEM simulated band gap of a single unit cell ranges from 6.0 Hz to 64.8 Hz, while the analytical model shows a band gap from 9.6 Hz to 59.5 Hz. The manufactured NSLR prototype features parasitic resonator rotations, requiring additional stiffness constraints to test its vibration attenuation properties in practice. These analyses show the promising capabilities of the NSLR unit cell as a building block in metamaterials to protect
structures from low-frequency vibrations at a wide range.","Locally-resonant metamaterials; Bandgap; Passive Vibration Isolation; Compliant Mechanism","en","master thesis","","","","","","","","2025-11-07","","","","Mechanical Engineering | Mechatronic System Design (MSD)","",""
"uuid:d6869e59-57a0-4dca-9d4d-19050a0e1a89","http://resolver.tudelft.nl/uuid:d6869e59-57a0-4dca-9d4d-19050a0e1a89","Macaulay's methode toegepast met invloedslijnen","Jankie, julia (TU Delft Civil Engineering & Geosciences)","van Woudenberg, T.R. (mentor); Hoogenboom, P.C.J. (graduation committee); Delft University of Technology (degree granting institution)","2023","Macaulay's method utilizes singularity functions to describe discontinue forces acting on beam structures. This method has been extended to determine internal forces and influence lines, making use of a single expression. The method can be applied to analyze all possible scenarios for both one-dimensional and two-dimensional constructions.","Macaulay's method; Influence lines; Singularity functions; Structural mechanics","nl","bachelor thesis","","","","","","","","","","","","Civil Engineering | Structural Engineering","",""
"uuid:d04a082a-4721-4126-821c-f5044cbcd93f","http://resolver.tudelft.nl/uuid:d04a082a-4721-4126-821c-f5044cbcd93f","Bewogen Ruimte: architectuur door de ogen van een filmmaker","Haak, Melle (TU Delft Architecture and the Built Environment)","van de Pas, R.R.J. (mentor); Vink, M.G. (mentor); Hehenkamp, E.W.M. (mentor); Snijder, A.H. (graduation committee); Delft University of Technology (degree granting institution)","2023","Hoewel ik tijdens mijn opleiding leerde ontwerpen, voelde ik dat ik maar weinig grip kreeg op de dynamiek waarmee we dingen beleven. We ontwerpen gebouwen van steen en hout, die stilstaan; toch lijkt alles wat zich tussen de muren van onze huizen en steden afspeelt bewegelijk en tijdelijk. We nemen de materiële wereld allemaal ongeveer hetzelfde waar met onze zintuigen, toch beleven we alles anders. Soms beweeg ik me vluchtig en onverschillig en soms langzaam en aandachtig. Soms brengt een geluid of geur me in vervoering en vergeet ik voor even de wereld om me heen. Soms verdwaal ik in een dagdroom; en terwijl mijn lichaam zich nog altijd begeeft in dezelfde wereld, reis ik in gedachten door verschillende plekken en tijden tegelijk.
Ik stelde aan het begin van dit jaar de vraag: wat is de geleefde ruimte? Een ruimte die gekleurd lijkt door onze herinneringen, associaties, verbeelding en onderbewustzijn. Ik richtte me in mijn onderzoek op film, omdat filmmakers - meer dan architecten - een taal hebben ontwikkeld die op expliciete manier uitdrukking geeft aan de belevingswereld van de toeschouwer. Filmmakers zijn zich ervan bewust, hoe je met montage - een nauwkeurige samenstelling van licht, geluid, schaal, beweging en ritme - de emotie van de toeschouwer kan sturen. Door het scheppen van relaties en met behulp van suggesties en associaties ontstaat nieuwe betekenis.
Aan de hand van drie cinematografische ordeningsprincipes, bestudeerde ik de effecten van een architectonische montage op de belevingswereld van de gebruiker. Ik zocht naar een nieuwe taal om de dynamiek van licht, geluid, geur en beweging op een expliciete manier te integreren in het ontwerpproces.
This research aims to gain insight into key stakeholders’ perspectives regarding current data exchange practices. The guiding research question for this thesis is “How can the data accessibility and interoperability of Material Passports be optimised in order to improve the effectiveness of its implementation within practice?” It is answered with the help of four sub-questions. The first sub-question aims to gain an understanding of the key concepts and characteristics of MP data exchange with the help of a literature review. This is followed by the second sub-question which explores the data exchange roles of key stakeholders per building lifecycle stage. The third sub-question seeks to gain an understanding of the main challenges faced by key stakeholders regarding MP data exchange through the use of semi-structured interviews. This is followed by a case study which seeks to examine the TU Delft’s perspective as a public client and data owner regarding making data more accessible and interoperable for other stakeholders through the use of semi-structured interviews.
It is found that although ample data on materials and components exist, they are currently not accessible or interoperable for stakeholders across the sector. Stakeholders can be data providers or data extractors, however the responsibility for making data accessible and interoperable lies with the data owner who in most cases is the client. A lack of; standardised data, a government initiated centralised platform, data structure, and standards and norms are found to be the major challenges associated with data exchange of MPs. From a public client (TU Delft) perspective, it is found that although there is an understanding of improving data exchange, data privacy is a major hurdle that needs to be overcome before data can openly be shared with all stakeholders in the sector. In order to enforce a shift in the working methods of the building sector, more clients need to start demanding data from stakeholders.","material passport; Data exchange; Stakeholders; accessibility; interoperability; Circular economy (CE)","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences","",""
"uuid:27a49715-f5df-439e-bf9c-ebfd1c8b80db","http://resolver.tudelft.nl/uuid:27a49715-f5df-439e-bf9c-ebfd1c8b80db","Public Interior Wunderkammer","Bernátek, David (TU Delft Architecture and the Built Environment)","van de Pas, R.R.J. (mentor); Harteveld, Maurice (mentor); van de Voort, J.A. (mentor); Mulder, André (graduation committee); Delft University of Technology (degree granting institution)","2023","Our cities are densifying to accommodate the growing urban population within the existing urban fabric. More and smaller homes are being built. This appears to be the result of an ongoing global housing crisis. Therefore, good quality public space becomes even more essential, as it acts as the expansion of our living rooms. It is the immediate living environment, where we live in, use, appropriate, and experience it together (Harteveld, 2020).
The growth of private spaces within our city limits, a reaction to the housing crises, should also lead to the expansion of our public space network. Especially if new building mass is introduced within city limits by filling up gaps, leftover spaces, or public spaces, which is then substituted by a great amount of private spaces. This ‘eating up’ of public spaces is f.e. happening with the planned projects of Kavel 6/7 and Habitat Royal, which are expanding the private areas of Amsterdam Zuid into the Beatrixpark, or Rotta Nova in Rotterdam, which is replacing a publicly used green space with a great amount of private spaces. These approaches of densification make the public space network of our cities shrink. Losing public space and not giving much more back than winning new private spaces. The logical outcome would be to reintroduce public and collective space (public interiors) as part of those projects to equal up for the deduction of public space, however, in these examples, it is not happening.
A merge of public space with private buildings as a response to densification could be achieved with public interiors. These expand the network of public space into the insides and outsides of private buildings. They are a vital component of the extension of the public space network and can become part of our everyday urban lives (Harteveld, 2014).","Densification; Public interior; Public space; Private space; Twin phenomena; Hybridity; Architectural Tools; Toolbox; Secondary public space; Stacking the city","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Explorelab","","52.339179, 4.877971"
"uuid:6e923b63-0fc1-45d4-abc4-475b6eb3f80d","http://resolver.tudelft.nl/uuid:6e923b63-0fc1-45d4-abc4-475b6eb3f80d","Diagnosis Methodology for STT-MRAM: Defect Identification and Classification","Aouichi, Ahmed (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Computer Engineering; IMEC)","Hamdioui, S. (mentor); Taouil, M. (mentor); Gao, C. (graduation committee); Kim, W. (mentor); Rao, S. (mentor); Delft University of Technology (degree granting institution)","2023","This thesis focuses on identifying and classifying defects in STT-MRAM technology using novel and machine learning approaches. The thesis discusses the basic principles of STT-MRAM and the semiconductor chip manufacturing process and test stages. The research aims to develop novel methods and explore machine-learning approaches to diagnose defects in STT-MRAM devices. The current defect identification methodologies have shown certain cost, speed, and scalability limitations. The thesis presents DAT-based and ML-based Diagnosis methodologies to identify and classify STT-MRAM unique defects to address these challenges. The methods are evaluated and validated on experimental wafers performed at IMEC in Leuven, Belgium.
DAT-based Diagnosis involves automated defect identification in STT-MRAM based on identifying features automatically extracted from specialized measurements targeting the unique defects, Pinhole, Intermediate State, SAF Flip, and Back-Hopping. ML-based Diagnosis uses machine learning techniques to classify defects using MTJ features extracted from low-cost measurements. Data collected from electrical measurements on experimental STT-MRAM devices serve as the basis for evaluating the developed methodologies. The thesis also discusses data analysis, including data visualization, feature correlations, and outlier analysis for future research. Furthermore, a machine learning training process is performed, including hyperparameter optimization and evaluation using F-score and B-accuracy metrics to assess the model's performance and the ability to generalize on unseen data.
DAT-based Diagnosis aims to maximize the defect detection accuracy at the expense of measurement costs. In contrast, ML-based Diagnosis minimizes the measurement cost while maximizing the detection accuracy for robust and balanced classification. However, the DAT-based Diagnosis is not verified using PFA to validate the defect types identified by the developed methodology. Furthermore, the ML-based Diagnosis uses training data labeled by the unverified DAT-based Diagnosis approach to train machine learning models. Despite these limitations, the results have shown valuable insights into defect identification and classification, proving a robust framework for diagnosing STT-MRAM devices. Additionally, a scientific paper is submitted on march-based diagnosis, adapting the DAT-based Diagnosis method to industrial chips that are limited in extracting the identifying features.
The transition to an MTH aligns with the global trend of promoting sustainable transportation alternatives, emphasizing the importance of integrating various transport modes to create efficient and user-friendly connections. Royal Schiphol Group (RSG) is committed to develop the world’s most sustainable and high-quality airports, reflecting the societal push for responsible transport systems.
The mobility industry’s increasing focus on the intersections of various transport subsystems emphasizes the need for integrated services and a seamless journey experience. By adopting the role of an MTH, Schiphol can meet the evolving expectations of travellers.
However, implementing a multimodal service and infrastructure is complex, and understanding passenger dynamics, constraints, and needs during intermodal transfers is crucial. Schiphol already serves as a hub between various transport modes, but there is a lack of insights into non-air travellers, including as bus and train travellers.
To bridge this knowledge gap and enhance rail-bus transfers, this project aims to design a support system for the S&AP department of RSG. This system will provide valuable insights into traveller needs and desires during rail-bus transfers. These insights will serve as argumentation for decision-making in construction projects. Through these insights, Schiphol can make well-informed decisions to enhance passenger satisfaction, streamline the rail-bus transfer process, and ultimately solidify its position as a customer-centric MTH.
The core objective of this project is the development of a support system that utilizes analysed data to present traveller preferences. To achieve this goal, various aspects require comprehensive understanding, which is categorized into three key themes,
First, the support system needs to create value for RSG by providing insights relevant to the organization and ensuring these insights contribute to the company’s objectives.
Secondly, the support system must be optimized for usability and interaction, ensuring that RSG employees can easily access the desired insights.
Lastly, there needs to be a seamless integration of the support system into RSG’s workflow, system operation and digital environment.
The support system should provide valuable insights but must avoid overloading users with information. Therefore, it focuses on three key aspects: differences between travellers, their needs and desires, and the transfer direction between bus and train. The system’s architecture enables users to specify their preferences and receive insights tailored to their criteria. To strike a balance between providing in-depth insights and maintaining a clear overview, the system categorizes traveller needs and desires into six main categories, with the option to explore detailed insights within each category.
The system design has been validated through usability studies and consultations with relevant departments, aligning with the organization’s workflow. In conclusion, the project has successfully met all criteria, indicating that the support system adds substantial value to RSG.","Transfers; Schiphol Airport; Multimodal Transport Hub; Rail-Bus; Royal Schiphol Group; Transfer insights; Support system","en","master thesis","","","","","","","","","","","","Design for Interaction","",""
"uuid:14cb7e8c-dfaf-410c-a4f3-08f7e2c31f7c","http://resolver.tudelft.nl/uuid:14cb7e8c-dfaf-410c-a4f3-08f7e2c31f7c","La Solidarite de Fatima","Bokzini, Souad (TU Delft Architecture and the Built Environment)","van de Pas, R.R.J. (mentor); van de Voort, J.A. (mentor); van Dooren, E.J.G.C. (mentor); Delft University of Technology (degree granting institution)","2023","","","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Explorelab","",""
"uuid:67f78225-c0dc-4d04-ac7b-088cddf23cbb","http://resolver.tudelft.nl/uuid:67f78225-c0dc-4d04-ac7b-088cddf23cbb","Enhancing Energy Efficiency and Sustainability in Healthcare: Implementing a Heat Exchanger for Carbon Footprint Reduction","Alkemade, Selwin (TU Delft Mechanical, Maritime and Materials Engineering)","Horeman, T. (mentor); van Straten, Bart (graduation committee); Delft University of Technology (degree granting institution)","2023","This paper addresses the urgent need to optimize the GreenCycl facilities energy utilization, by harnessing heat from the effluent of three thermal washing-disinfection machines into the preheating of cold clean water. Currently for every washing-disinfection cleaning program, 60 times a week, 105 liters of water with a temperature of 60 \degree Celsius is discharged in the drain. This is not in line with the goals setup by the government and the mindset of GreenCycl.
The study begins with a comprehensive analysis of the current situation, while documenting the properties and conditions. Subsequently concepts are generated with help of a morphological chart and a Harris profile is employed to select the most promising concept, this is further elaborated. Computational Fluid Dynamics (CFD) simulations are conducted to optimize the performance of the heat reclaiming system. Finally, the results of the CFD simulations are validated with experimental research.
By reintroducing 67\% of the effluent back into the heat exchange system, a continuous flow across the heat exchanger of 35 liters per minute can be established with an operation duration of 2.5 minutes per washing-disinfection machine. Resulting in the heat reclaiming system to only operate when cold clean water is flowing through the HEX. If implemented at the GreenCycl facility, this innovation could potentially save approximately 7600 kW of electrical energy and reduce Carbon Dioxide emission by 1129 kg annually.
This study not only addresses a pressing environmental concern but also offers an easy and efficient solution with significant economic and ecological benefits.","Healthcare; Carbon emission; Heat Exchanger; Sustainability; Washing machine","en","master thesis","","","","","","","","","","","","Biomedical Engineering","Evaluawaste",""
"uuid:485ce46b-a4fb-4122-abc5-b1275347d94a","http://resolver.tudelft.nl/uuid:485ce46b-a4fb-4122-abc5-b1275347d94a","Landscapes of Power: Reconfiguring the energy production landscape of Western Macedonia","Kalligeri Skentzou, Anna (TU Delft Architecture and the Built Environment)","Furlan, C. (mentor); Dabrowski, M.M. (graduation committee); Delft University of Technology (degree granting institution)","2023","The beginning of the 21st century is defined by geopolitical tensions around resources, an expected shortage of fossil fuel resources and the emerging climate crisis, amplifying the urgency of the transition to renewable energy sources. This energy transition has been at the forefront of public discussion, framed by the 2016 Paris Agreement and the 2019 European Green Deal. In this context, European member states must accelerate the decarbonisation of their industries and the transition to renewable energy sources. As each member state attempts to deal with this challenge, issues associated with social and spatial justice in coal-intensive European regions arise, calling for a coordinated, inclusive and collaborative plan aiming at a just transition.
This thesis uses the coal intensive region of Western Macedonia as a case study and proposes the reconfiguration of the energy landscape by formulating a territorial vision, based on an analysis and the evaluation of scenario building. More specifically, it develops a series of spatial and non-spatial strategies aimed at restoring ecological integrity, diversifying the energy production, re-using heritage spaces and promoting governance collaboration and social inclusivity. By examining the vulnerabilities, potential, and opportunities present in the territory of Western Macedonia, this thesis seeks to promote the reconfiguration of Western Macedonia, embracing principles of regenerative development, adaptive re-use, participatory planning and collaborative governance.","energy transition; energy landscape; Western Macedonia; regional design; adaptive reuse; Regenerative Design","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Landscape Architecture","","40.581199, 21.659957"
"uuid:1bdef8d0-71ff-42ef-a66c-e31686b227bf","http://resolver.tudelft.nl/uuid:1bdef8d0-71ff-42ef-a66c-e31686b227bf","The line in the Landscape: Exploring the social and spatial opportunities of implementing innovative high speed railroad technology in the formation of transport flowscapes in the Netherlands","Credendino, Giordana (TU Delft Architecture and the Built Environment)","Cannatella, D. (graduation committee); Verschuure, G.A (mentor); Delft University of Technology (degree granting institution)","2023","In the past decade, many discussions on the need to reduce our carbon footprint have led the EU to open a public discourse on the applicability of high speed railroad travels within the continent. But spatial plans regarding the implementation of said infrastructure are lacking and the topic of emerging railroad technologies has not surfaced in our media yet. The opportunities behind creating a sustainable European network are endless, but where is the research? This thesis aims at opening the discourse on alternative railroad infrastructure technology in the fields of social and spatial acceptance based on the frameworks of flowscapes (operative infrastructure as landscape and landscape as infrastructure) and the three dimensions of perception, function, and symbolism in order to assess the spatial and social opportunities of designing with innovative railroad technologies. This visionary research sees the cultural landscape of the Netherlands as initiator of this development, in which the new infrastructure aims at connecting the landscape, focusing on the character and values of the province of Overijssel, based on an analysis of technology through art. As a result of the research, the technology proves its position as a guiding Line in the Landscape, providing readability in the three dimensions in terms of narrative, landmark and connection.","Landscape architecture; Railroad Technology; Social Value; Innovative Infrastructure","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Landscape Architecture","",""
"uuid:850a64df-46e1-477b-b1bd-c066eca5e24e","http://resolver.tudelft.nl/uuid:850a64df-46e1-477b-b1bd-c066eca5e24e","Energy-efficient and 'healthy' offices: An approach for office renovations focused on energy efficiency and Indoor Environmental Quality","van der Ham, Anja (TU Delft Architecture and the Built Environment)","Qian, QK (mentor); Straub, A. (graduation committee); Delft University of Technology (degree granting institution)","2023","Renovation of existing buildings is proposed as a solution for buildings that do not fit the Climate Target Plan 2030. In the Netherlands, there is a new mandate requiring Dutch office buildings to attain a minimum EPC class C rating by January 1st, 2023. Recent studies indicate that 10% of Dutch office buildings are currently rated at EPC class D or lower, while numerous existing office buildings have yet to obtain an EPC rating. This situation necessitates a surge in renovation projects in the near future. However, a complex relationship exists between energy-efficient measures and Indoor Environmental Quality (IEQ) post-renovation. Healthy buildings, characterised by adequate IEQ, contribute to heightened overall satisfaction and productivity among their occupants. This research is centred on crafting an advisory report aimed at guiding the decision-making process preceding office renovations for owners of Dutch owner-occupied offices. The following main research question relates to the goal of this research: “How can the renovation decision-making process, prior to renovation, of private owners of Dutch owner-occupied office buildings be guided with a focus on improving energy efficiency and Indoor Environmental Quality?”. The objective is to surpass the EPC class C requirements while concurrently prioritising IEQ enhancements to boost employee satisfaction and productivity. To achieve this, several case studies were conducted through in-depth interviews with stakeholders involved in the renovation projects. This approach sought to gain insights into the decision-making processes of office owners prior to the execution of renovation practices. The findings of this research hold significance for those initiating future office renovation projects, project managers, and public authorities seeking strategies to accelerate the rate of energy-efficient and healthy office renovations. The study’s outcomes indicate that the decision-making process preceding office renovations can indeed be steered towards achieving both energy efficiency and improved IEQ. This can be accomplished through a comprehensive and cooperative approach that emphasises awareness, education, regulation, and financial security.","office renovations; renovation guide; Indoor Environmental Quality; healthy offices","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Management in the Built Environment","",""
"uuid:23cd7a48-b475-4a14-96c0-f3cc0ba2e7fc","http://resolver.tudelft.nl/uuid:23cd7a48-b475-4a14-96c0-f3cc0ba2e7fc","Enhancing Musculoskeletal Injury Rehabilitation and Prevention in Rural Areas: Exploring Vibrotactile Feedback Usage in Rural Areas","Singh, Dinesh (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Biomechanical Engineering)","Prendergast, J.M. (mentor); Abbink, D.A. (mentor); Vardar, Y. (graduation committee); Delft University of Technology (degree granting institution)","2023","Shoulder injuries, prevalent worldwide, often occur from ageing and accidents. In Western countries, these injuries primarily afflict the elderly population, while in rural regions of Bangladesh, Iran, India, and Pakistan, they affect younger individuals who are often the family's primary earners. Due to that, preventing and aiding the recovery of shoulder injuries is crucial. To address this, strain maps with vibrotactile feedback, emerge as a promising solution. However, the feedback system must be affordable, compact, comfortable, user-friendly, easily understood, and portable to suit the local environment. Vibrotactile feedback appears promising but can distract the user from work. Hence, this study seeks to investigate if vibrotactile feedback can be paired with strain maps to guide users in maintaining healthy postures and reducing the risk of shoulder injuries in rural areas, where visual feedback is used as a benchmark. To provide feedback using strain maps, shoulder angles are determined using Python's OpenCV and MediaPipe libraries. PyGame is utilized to display the strain maps, and OpenCV helps delineate boundaries between regions of high and low strain within the shoulder. Visual feedback is integrated into the strain map display, while vibrotactile feedback is delivered through a wearable haptic device. Despite challenges related to axial rotation accuracy and the camera-dependent nature of shoulder angle measurements, user experiments, conducted independently for shoulder elevation and planar elevation, reveal that vibrotactile feedback shows better performance compared to visual feedback. Consequently, this study concludes that vibrotactile feedback has the potential to prevent shoulder injuries with strain maps, but also still needs to improve for future work.","Shoulder Injuries; Vibrotactile Feedback; Visual Feedback; Rural Areas; Strain Maps; MediaPipe; OpenCV","en","master thesis","","","","","","","","","","","","Mechanical Engineering | BioMechanical Design","",""
"uuid:0c8b7c51-f894-4a3d-b48f-27c2653f3048","http://resolver.tudelft.nl/uuid:0c8b7c51-f894-4a3d-b48f-27c2653f3048","Finding Common Water: Empowering localized autonomy of dike management for an adaptive Rhine River.","Berkien, Jens (TU Delft Architecture and the Built Environment; TU Delft Urbanism)","Balz, Verena Elisabeth (mentor); Aalbers, K.P.M. (graduation committee); Delft University of Technology (degree granting institution)","2023","The Rhine River distributes water to more than 60 million residents, vital industries, and important agricultural sites across a total of eight countries. However, due to climate change, the availability of water resources has become increasingly dependent on seasonal supply and internal distribution (UNESCO, 2009). Moreover, extended periods of high river flow have the potential to pose threats to the urbanized regions along the Rhine (IKSR, 2011; Rottler et al., 2021; Stahl et al., 2022). In light of these developments, questions arise concerning the rights to use and manage the water. Simultaneously, water governance along the Rhine remains weak, with limited coordination between nation-states, sectors, and other relevant stakeholders, resulting in minimal influence at the local level (Rietveld et al., 2013; Akamami, 2016; Moodie, et al., 2022). Against this backdrop, this project focuses on the spatial element of the ""dike"" as a mechanism to control water flows and simultaneously restore the lost connection between local stakeholders and the Rhine.
The project, titled ""Finding Common Water,"" employs the new governance principle of Active Subsidiarity to prioritize local and regional autonomy in water management and identify issues that can only be addressed at higher levels of governance. Its goal is to investigate the potential for delegating the decision-making process of dike management to local levels of society. By enabling self-organizing capacity at lower levels of government, independent stakeholder systems can be synchronized to support adaptive water governance and localized protection.
The methodology of the project comprises several components. It includes literature review studies to enhance understanding of changes in governmental schemes in the transition to adaptive water governance. Additionally, a socio-spatial analysis is conducted on the Rhine River to assess current conditions related to drought, water discharge trends, water usage, and water management. To assign water management to local levels of society, the areas surrounding the Rhine are viewed as hydro-social territories. These territories are based on the mutual relationship between ""water"" and social, political, economic, cultural, and biophysical systems at a particular scale.
Drawing from the Dutch water management, a roadmap is created, following the principles of Active Subsidiarity toward localized dike autonomy. This roadmap empowers local stakeholder groups to evaluate their capacity to self-organize their relationship with the river through the spatial element of the dike. An assessment of indicators is made to evaluate the potential for localized dike autonomy. This is divided into four main subcategories: The Authoritative Region, The Dike, The Suitability Conditions, and The River Dynamics. By creating a calculation formula for these four main subcategories, potential locations along the Rhine suitable for localized dike autonomy can be identified. Finally, a test case is utilized to demonstrate the potential spatial outcomes of local dike autonomy.. Finally, a testcase is used to show the possible spatial outcomes of local dike autonomy.
The research addressed four sub-research questions that collectively provided answers to the main research question: \textbf{\textit{""What characteristics of an Appropriate Medical Equipment label would facilitate the intended use of medical equipment in low- and middle-income countries?""}} To answer the main research question, a design approach was employed, proving to be a valuable problem-solving method for this multifaceted problem. The design approach encompassed four phases: exploration, ideation, prototyping, and prototype review. In the exploration phase, four key steps were undertaken. Firstly, a literature review was conducted to investigate the current usage and experiences related to labels and certificates for medical equipment as well as labels in general, with a focus on experiences pertaining to medical equipment labels and certificates. Secondly, scientific literature was used to identify system factors influencing the life cycle of medical equipment. Insights from this literature were translated into IDEF frameworks, which formed the foundation for subsequent interviews. These IDEF frameworks served as structured way of showing information and were used as boundary objects throughout the research and interviews. Thirdly, interviews were conducted with experts, validating the information obtained from the literature and enhancing the IDEF framework. The fourth step was consolidating the insights to formulate a problem statement. This problem statement encapsulated key stakeholders' needs, requirements, desires, and dilemmas. Following the accumulation of knowledge from the exploration phase, the ideation phase began. During the ideation phase the design space matrices were developed for each of the categories. This design space matrix showed the decision making process between categories and means. The third phase, prototyping, involved synthesizing the knowledge gathered from the previous phases to create a prototype. Lastly, in the review prototype phase, the prototype was discussed with experts who provided feedback and opinions. Following the prototype review, consideration was given to future steps, determining the best approach for addressing this complex problem.
The study concludes that to facilitate the intended use of medical equipment in LMICs, a product label should incorporate essential characteristics, identified through a comprehensive review of literature and expert interviews. These characteristics encompass safety, design orientation, training, finance, maintenance, spare parts, service, usability, transparency, and end-of-life considerations. By prioritizing and integrating these features, the label has the potential to indirectly improve the overall life cycle of medical equipment in LMICs. The requirements for such a product label are identified through expert interviews, encompassing training, technical aspects, and safety considerations.
Beyond individual characteristics of the label itself, this study also explored the success of label implementation for medical equipment in LMICs. Several concerns require attention for a successful label implementation. The concern covered in this research is the potential misalignment of values and agendas among stakeholders can hinder commitment to a new product label and its prototype. To address this, incentives should be tailored to meet the specific needs of each stakeholder. Research indicates a preference for the bottom-up approach in label development due to its effectiveness in managing complexity and enhancing project success rates. Starting with end-user testing and progressing upward to demonstrate the label's value and encourage adherence to its standards can motivate manufacturers. By integrating the label's unique characteristics with advocacy efforts and a bottom-up approach, it has the potential to facilitate the intended use of medical equipment in low- and middle-income countries, enhancing the crucial role of medical equipment in healthcare systems in these regions.
The findings in this thesis hold significant importance for individuals seeking solutions to reduce the high rates of unused or non-functional medical equipment in LMICs. This thesis explores the distinctive characteristics of a label and how these characteristics can address the challenges present in the medical equipment life cycle. By gaining a clear understanding of these issues, organizations and experts can leverage these insights when developing solutions to reduce high percentages of unused and non-functional medical equipment, such as the product label. Lastly, the thesis introduces an initial prototype for a product label for medical equipment in LMICs. This prototype is a start for future study and can be used as a starting point for the actual development of the product label.","LMICs; Appropriate Medical Equipment; Low and Middle-Income Countries; Labeling; Characteristics; Prototype label; IDEF framework; Design; Medical equipment; Challenges","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:a8c53a21-d461-4d77-bfd9-d37dca1e42c5","http://resolver.tudelft.nl/uuid:a8c53a21-d461-4d77-bfd9-d37dca1e42c5","Accelerating MA-XRF Data Acquisition by Exploiting Local Spatial and Spectral Relations within a Hyperspectral Datacube: An Approach through Wavelet Denoising","Huijbrechts, Maartje (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Delft Center for Systems and Control)","Van de Plas, Raf (mentor); Alfeld, M.W.E.M. (graduation committee); Myers, N.J. (graduation committee); Delft University of Technology (degree granting institution)","2023","Macro X-ray fluorescence (MA-XRF) is a recently developed technology allowing to obtain elemental information from cultural heritage objects. This information can, for example, be used to identify pigments used in a painting. Yet, the extended period of time it takes to scan an object is a major issue within MA-XRf. For instance, it took about 60 days to scan the Ghent Altarpiece. The long scanning time is a consequence of the necessary dwell time per pixel to create a robustly interpretable spectrum: the higher the dwell time, the higher the signalto-noise ratio (SNR), hence, the easier to detect elements. This thesis explores a possible solution for this problem using a denoising algorithm that increases the signal-to-noise ratio post-acquisition by exploiting the similarity between neighbouring pixels and spectra. To this end, a customized method of wavelet filter bank denoising is proposed. Current thresholding methods used in wavelet filter bank denoising are not suitable for filtering MA-XRF data, therefore, a novel thresholding method is introduced. Here, the widely used universal thresholding method is used as a basis, for which the formula for calculating the standard deviation of the detail coefficients of a channel is altered. Several design parameters of wavelet filter bank denoising were evaluated using a synthetic dataset, for which the performance quality indicators root mean square error (RMSE), mean absolute error (MAE) and SNR were determined. The parameters for which we optimized were the mother wavelet, the number of decomposition levels, and the number of neighbouring channels used for determining the standard deviation σ for thresholding. Good performance was obtained with the haar, db2, and coif1 wavelets, all at 3 levels of decomposition. A suitable number of neighbouring channels depended on the decomposition level and was determined to be 3 (on each side of the channel). Herewith, the signal-to-noise ratio was improved for both the average pixel spectra and the sum spectrum. The filtered synthetic dataset simulated to have a dwell time of 0.5 seconds had a SNR approximately equal to the raw synthetic dataset simulated to have a dwell time of 0.75 seconds. Hence, the algorithm succeeded in lowering the necessary dwell time. A case study of a daguerreotype was used to test the proposed denoising algorithm.","MA-XRF; Filter; Wavelet; Filter Bank; denoising","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Systems and Control","",""
"uuid:a9f3ac01-edfb-4c07-bcfe-4998aeaa3aed","http://resolver.tudelft.nl/uuid:a9f3ac01-edfb-4c07-bcfe-4998aeaa3aed","Brainwise with the Self-portrait app: Providing child patients with a meaningful translation of their test-results","Plat, Benthe (TU Delft Industrial Design Engineering)","Gielen, M.A. (mentor); Melles, M. (mentor); van Veelen, M.L. (graduation committee); Delft University of Technology (degree granting institution)","2023","This report delves into the challenging process of translating complex tests from the Child Brain Lab into a design that is both accessible and engaging for children. The Child Brain Lab, part of the Erasmus MC Sophia Children’s Hospital, conducts research on brain development to gain a better understanding of the course of brain disorders and improve treatments for children with brain disorders. In return for children’s participation in the lab, the hospital aims to provide them with a child-friendly patient dossier: The Self-portrait. The goal of this project is:
To design a digital solution that translates the results from a selection of tests that are performed in the Child Brain Lab, into a meaningful contribution for children (developmental age 6-12 years old) with brain disorders, that will increase their participation in their care path, and positively support their developing self-image.
To design a solution that caters to the needs of the child patients, first the problem space was explored, through literature research and interviews with stakeholders. Within the age range of the target audience, children develop their language skills and transition from imaginative thinking to more logical reasoning. These cognitive abilities influence the formation of their self-image, which led to the framework for contributing to self-image: ‘Look what I did’ - ‘Look how I did it’ - ‘Look how I did it and what I learned from it.’ This framework was used to adapt the app to the needs of the target audience. In addition, the participants’ brain disorders present additional challenges, such as poor eyesight and a need for predictability.
The tests for which a translation is being made in the app are the EEG, IQ test, and walking mat. Each of these tests comes with its own set of challenges. For example, the data from the EEG test is complex and elusive for children, and the analysis is quite intricate for physicians. The results of the IQ test are highly valued.
The discovery phase revealed five trade-offs, such as the balance between providing honest information or protecting a child by sharing only positive information. The insights led to the design goal:
Create a personally rewarding visualization of the test-data of the EEG, IQ-test and walking mat for each child that visits the CBL, by highlighting their personal achievements and empowering children to become aware of and accept who they are, in a form that is integrated in the clinical workflow of the Pediatric Brain Centre, and supportive during the full care journey, so that HCPs see the Self-portrait as an enrichment to their work.
The result is an interactive prototype of The Self-portrait, inviting children to explore the world of their own brains. Each test is developed with its own character. For instance in the case of the walking mat, animals are used to give children insights into their walking patterns, envisioning enriched dialogues between children and physiotherapists, potentially leading to improvements.
Throughout the app’s development, all stakeholders have been involved multiple times, ensuring the right balance is struck in the design between presenting accurate information aligned with clinical practice while also appealing to children.
Through this endeavor, the project aims to bridge the gap between complex medical data and child-friendly interpretations, fostering a better understanding and engagement with one’s health metrics.
More sustainable transport like cargo bikes or light electric vehicles could play a role in solving these problems on the relatively short term. However, because they typically have smaller capacity and have smaller ranges than the vans that are currently used they are not the default solution for consignment in the city; distribution centres nowadays typically lie too far away from the end consignee to effectively employ these type of vehicles.
The fact that distribution centres lie so far away from the city stems from more latent problem of the last mile; its inaccessible and un-communal nature.
In this project I propose 7 ‘design activities’ in response of the aforementioned problems: cooperation, incentivisation, standardisation, decentralisation, integration (in the city), automation and consolidation. Based on these design activities I proposed three types of urban consolidation centres that facilitate smaller types of transport while at the same time considering the aforementioned design activities.
Despite extensive theoretical knowledge of nonclassical gas dynamics, which includes rarefaction shock waves (RSWs), there is still a lack of compelling experimental evidence supporting their existence. The motivation for the research documented in this dissertation is two-fold: firstly, it is crucial to conduct experiments that can provide empirical validation of nonclassical gas dynamics, with a specific focus on observing RSWs, which have proven elusive in previous attempts. Secondly, performing accurate measurements of fluid properties in the dense-vapour thermodynamic regime has the potential to improve the thermodynamic models of BZT fluids or fluids made of complex organic molecules in general. This in turn can contribute to a more accurate characterisation of flows in practical applications that involve these fluids, such as turbine flows in Organic Rankine Cycle (ORC) systems or compressors in high temperature heat pumps.
This research work aimed to provide conclusive experimental evidence for the existence of nonclassical expansion shock waves in the flows of a candidate BZT fluid, siloxane D6. For this purpose, two novel test facilities namely the Asymmetric Shock Tube for Experiments on Rarefaction Waves (ASTER) and the Organic Vapour Acoustic Resonator (OVAR) have been conceived, developed, designed, built and commissioned at TU Delft. Relevant theoretical studies were performed to complement the experimental observation of nonclassical effects. Novel measurements of fluid properties in the nonclassical gasdynamic region of the candidate BZT fluid were executed, the outcomes of which are useful for the improvement and the optimisation of thermodynamic models for this fluid.
Magnetic coupler design
The key performance indicators of an IPT system include power transfer capability, power density, power efficiency, and misalignment tolerance. Due to conflicts among these performance indicators, it is indispensable to formulate the design of IPT charging pads as a multi-objective optimization (MOO) problem. By using finite element (FE) models, the magnetic field property of a coupler can be computed. However, calculating the aligned and misaligned power losses at the rated power requires not only the magnetic field property but also the compensation strategy. The compensation strategy determines the load match method which is used to calculate the optimal load condition and the rated winding currents. Therefore, compensation strategy should also be considered for the magnetic coupler design. With the magnetic field distribution known, the power losses in the AC link can be calculated through the existing analytical method.
This thesis develops a MOO method that can find the performance space from the design search space of magnetic couplers. In the performance space, Pareto fronts can be obtained under different conflicting optimization objectives. The study shows that analytically calculating the AC link power efficiency is possible when the magnetic field is accurately computed at the rated condition. More importantly, the DC-DC power efficiency of the final prototype reaches $97.2\%$ which proves that the MOO design is vital to make full use of IPT technology.
Prediction and control of transient behaviors
IPT systems require capacitive/inductive components to form resonant circuits on both sides to improve the power transfer capability and power efficiency, while the compensation components also make the resonant stage of a high order. As a result, the analytical dynamic models of IPT systems are complex and mostly impossible to solve in the time domain.
This thesis proposes a new reduced-order dynamic modeling method that describes the transient behavior of a resonant stage from the energy point of view. The order of the resultant dynamic model is one-fourth that of conventional ones for SS compensated IPT systems. Also, a MPC controller is designed based on the proposed dynamic model. It is proven that simplifying the dynamic model is helpful in explaining how circuit parameters influence transient behaviors and also in facilitating the application of advanced control strategies in IPT systems.
Reduction of power fluctuation
The most obvious difference between static and dynamic IPT is the change in magnetic coupling. In DIPT applications, the magnetic coupling fluctuates from the maximum to a usable level as EVs move, so one of the main challenges of DIPT is to stabilize the pick-up power, especially for DIPT systems using segmented Tx coils where magnetic coupling changes more frequently. The conventional methods are either to overlap Tx coils or to add extra sets of the Rx sides, which are expensive in building costs.
This thesis presents the design of a segmented DIPT system using a multiphase Tx side. The Rx coil consists of two sub-windings connected in series with a relatively large spatial offset in the EV moving direction. One advantage of the proposed design is that the Tx coils are deployed loosely so the building cost can be reduced. The other advantage is that the pick-up power is seamless with a small ripple. The pick-up power demonstrates a $24.9\%$ ripple by experiments.
Detection of EVs and FOs
To minimize the Tx side power losses and magnetic field radiation, the detection of EVs and FOs should be implemented in DIPT systems. Considering the integration of the detection equipment into the charging pads, PCB coils become the most suitable candidate to sense the magnetic field for detection purposes. However, the detection of EVs and FOs are mostly discussed separately in the literature. There is a need to achieve these two detection functions within one set of PCB coils.
This thesis presents the design of detection equipment consisting of PCB coils installed onto charging pads and the detection resonant circuit (DRC) connected to Tx side PCB coils. It can be concluded that the detection of EVs and FOs can both be realized by measuring the variation of the magnetic field caused by their intrusion, and PCB coils demonstrate good performances in measuring the change of magnetic field together with DRC to amplify the detection signals.
This thesis focuses on the second approach, which is to explore the implementation of algorithms on modern quantum processors. Along all these implementations, we study the errors that cause these algorithms to derail from their ideal results. We attempt to understand, quantify and control these errors, in the hope that this provides useful insights into how to design algorithms for the modern hardware.
This thesis starts by introducing the topic of superconducting quantum processors and modern algorithms in the first two chapters. Then we move onto the three experiments, one chapter each, detailing our findings.
The first experiment cover an digital-analog implementation of a quantum simulation of light-matter interaction. We present the implementation that makes use of both digital (gates) and analog (evolution) blocks. The accuracy of the Trotterization technique is studied in detail, as well as the capability to study the photon population in the resonator. We manage to implement up to 90 Trotter steps and reproduce the behaviour in the ultra-strong coupling regime.
The second experiment presents an error mitigation technique, on an application of great interest to the field (molecular simulations). This application is a fully digital one, within the hot topic of variational algorithms for ground-state preparation. The mitigation technique, which is an invention of our own team (see referenced theoretical works) manages to reduce the algorithm error over an order of magnitude. In order to demonstrate this level of control, we quantify the error through accurate simulations of the quantum process and independent quantification of the parameters involved.
The third experiment presents another variational algorithm, this time to produce thermal states rather than ground states. Again, we pursue a detailed study of the many error mechanisms involved, in order to quantify and match the results obtained. We go beyond incoherent errors and add a coherent error mechanism common to our hardware architecture, the residual ZZ coupling.
Finally, we reflect on the final chapters about how to continue towards implementations that make the most out of modern, noisy, hardware.","quantum; quantum computing; quantum simulations; experimental physics; condensed matter physics; superconducting devices; superconducting qubits","en","doctoral thesis","","978-94-6419-969-7","","","","","","","","","QCD/DiCarlo Lab","","",""
"uuid:9a4ae159-69ab-4e20-b093-3f33351c0962","http://resolver.tudelft.nl/uuid:9a4ae159-69ab-4e20-b093-3f33351c0962","General Reinforcement Learning Agents for Crop Management","Theocharis, Thanasis (TU Delft Electrical Engineering, Mathematics and Computer Science)","Oliehoek, F.A. (mentor); Turchetta, Matteo (graduation committee); Krause, Andreas (graduation committee); Delft University of Technology (degree granting institution)","2023","Agriculture plays a vital role in the global economy, providing the necessary food and resources for human survival. With the world’s population projected to surge, the demand for food is set to escalate in the coming decades. This increasing demand, coupled with the challenges posed by climate change and the detrimental effects of pollution due to fertiliz-ers, underscores the urgency for more efficient and sustainable crop management strategies. Effective crop management is a complex and time-consuming task that involves various fac-tors, including climate conditions and soil quality. Traditional crop management strategies often rely on expert knowledge to guide the decision-making process, which may be sub-optimal and prone to error. Reinforcement learning (RL) has gained significant attention in recent years as a promising approach for decision-making and control in agriculture, aiding in the management process. RL environments such as CyclesGym [51], accommodate the design of agents that oper-ate within an agricultural system, often surpassing the performance of traditional strategies. However, the optimal policy may vary heavily depending on the specific field location, due to its specific weather conditions and soil quality. In this thesis, we aim to investigate the use of RL for managing fields in multiple locations with the aim of reducing training time and data and increasing robustness compared to independent training. To this end, we plan to use multi-task learning methods and optimizers to reduce total training time, to improve RL agents’ adaptability to changing environments, and to reduce data usage required for maximum performance across multiple agricultural fields.","Deep Reinforcement Learning; Crop Management; Multi-Task Learning","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:f15f9f16-16b0-484e-908e-a6a2a0ba35e5","http://resolver.tudelft.nl/uuid:f15f9f16-16b0-484e-908e-a6a2a0ba35e5","JDE packaging material warehouse strategy and process redesign: improving efficiency by reducing variability","Pries, Pieter (TU Delft Technology, Policy and Management)","Ludema, M.W. (mentor); Tavasszy, Lorant (mentor); Guldenmund, F.W. (graduation committee); Delft University of Technology (degree granting institution)","2023","","","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:ca0454e3-21a4-44e4-8140-41e7db20bdaf","http://resolver.tudelft.nl/uuid:ca0454e3-21a4-44e4-8140-41e7db20bdaf","Pressure-activated, colour-changing and flexible material for aiding lymphedema patients in performing the MLD massage: An explorative design study","Koudstaal, Loulou (TU Delft Technology, Policy and Management; TU Delft Mechanical, Maritime and Materials Engineering)","Trauzettel, F. (mentor); Sakes, A. (mentor); Jovanova, J. (graduation committee); Lussenburg, K.M. (graduation committee); Delft University of Technology (degree granting institution)","2023","The MLD massage is a key component of a lymphedema patient’s treatment. Currently, research is ongoing manifesting a transition from system care to self-care by designing robotic sleeves that are able to perform an effective and safe MLD massage enabling the patient to gain a sense of empowerment and ownership over their treatment and time. This research presents an innovative approach towards the MLD treatment by introducing an intermediate step: the bio-inspired design of the patient training education tool (PTET), a tool which aids the patient in performing the MLD massage safely and efficiently by themselves. The PTET is a pliable and slim sheet that easily adapts to the contours of the limb. Exerting manual pressure onto this sheet induces a colour change at a specific pressure threshold, giving the lymphedema patients a visual sign they have reached the required amount of pressure for this type of massage. The mechanism of colour change is inspired by the cephalopod’s dispersion and aggregation of its chromatophores. This study presents the design and validation of the working mechanism of a bio-inspired flexible colour-changing sheet, and first insights into the adaptability of the design variables and their relation to the threshold pressure, threshold indent and degree of colour change.","colour change; mechanism; bio-inspired design; pressure-activated; soft robotics; lymphedema","en","master thesis","","","","","","","","","","","","Mechanical Engineering | BioMechanical Engineering | BioInspired Technology","",""
"uuid:b4a8e9fb-3b95-44c3-9f47-22e1b38c43dc","http://resolver.tudelft.nl/uuid:b4a8e9fb-3b95-44c3-9f47-22e1b38c43dc","Recycling of SBS Asphalt Mixture with Polymer Network Reconstructive Rejuvenators","LI, BOWEN (TU Delft Civil Engineering & Geosciences)","Liu, X. (mentor); Lin, P. (mentor); Erkens, S. (graduation committee); Schlangen, E. (graduation committee); Hagos, Eyassu (graduation committee); Delft University of Technology (degree granting institution)","2023","This master's thesis addresses a critical gap in the field of road construction by focusing on the limitations of Styrene-Butadiene-Styrene modified bitumen (SBS-MB), a widely-used binder. While SBS-MB offers superior performance, its long-term efficacy is compromised due to various aging processes. Existing rejuvenators are insufficient for restoring the binder's original properties. To remedy this, our research introduces an innovative rejuvenator that provides a more comprehensive restoration of SBS-MB, especially in the reconstruction of the polymer network. The study employs a multifaceted evaluation approach, leading to an enhanced understanding of the rejuvenator's effectiveness and mechanisms of action. Furthermore, we validate the rejuvenator's efficacy using real-world, field-collected materials. The findings not only offer a more effective method for restoring aged SBS-MB but also hold promise for improving the recyclability of Reclaimed Asphalt Pavement (RAP), potentially leading to more sustainable road construction practices, particularly in the Netherlands.","Bitumen; Rejuvenation; Rejuvenator; SBS modified bitumen; Chemical rejuvenator; Aging; Mastic; Rheology","en","master thesis","","","","","","","","2025-11-01","","","","Civil Engineering","",""
"uuid:26f37734-3eaa-448c-8988-4011a7f72873","http://resolver.tudelft.nl/uuid:26f37734-3eaa-448c-8988-4011a7f72873","A River Reborn: An explorative landscape architecture design focussed on restoring natural river dynamics for the Nile River Basin","Huijboom, Hilde (TU Delft Architecture and the Built Environment)","Nijhuis, S. (mentor); Hooimeijer, F.L. (graduation committee); van der Putt, P.S. (graduation committee); Delft University of Technology (degree granting institution)","2023","The River Nile has been a lifeline for northeastern Africa for thousands of years, supporting the growth of civilization, agriculture, and trade. The history of the Nile can be traced back to ancient times. The fertile banks of the Nile have supported the civilization of the ancient Egyptians. Since Egypt received almost no rain, the ancient Egyptians worshiped the river and considered the water from the Nile as the source of life. The Greek historian Herodotus has written, “Egypt is the gift of the Nile”. The ancient Egyptians developed ways to make perfect use of the gift of water, a complex system of irrigation to irrigate their fields to produce large amounts of crops to support the growing population. The Nile also played a crucial role in trading routes in the region, goods were transported to the Mediterranean Sea and then traded throughout the ancient world. The relationship between people and the Nile was symbiotic during these ancient times. A harmonious balance between men and nature. For five thousand years, nature has dominated the river’s constitution and functions, but from the mid-nineteenth century to today, different countries and regimes have increasingly influenced the Nile River system. Ambitious water management of big irrigation projects and the building of large dams has resulted in an imbalance in the relationship between the river, delta, sea, and people. The landscape of the Nile River Basin has changed from dynamic and natural, to a highly controlled and obstructed river.The Nile faces multiple threats, including pollution, climate change, and overuse. The highly controlling mentality is causing these threats to accelerate, and increasing the overall decline in the resilience of the basin. This graduation project aims to evaluate the effectiveness of landscape architecture design interventions in reintroducing natural dynamics in the Nile River Basin and assess their potential to enhance the basin's ecological, and socio-economic value, hydrological functioning, and overall resilience.
For this, literature research was conducted. First an understanding of the current landscape of features of music streaming service was created. This led to the conclusion that personalised recommendations were the most relevant for this project, as they are driven by recommender systems. Next, different personalised recommendation features were linked to wellbeing. It was established that mood-based recommendations have the potential to contribute to hedonism, that activity-based recommendations have the potential to contribute to personal functioning and that discovery recommendations have the potential to contribute to personal development.
Given the alignment with the broader concerns of recommender systems, the project continued to focus on discovery features and personal development.
By analysing how current recommender systems operate in these feature, it was determined how that the recommender system of the new intervention should implement an ‘exploration mode’ approach and gradually introduce users to new items, allowing them to slowly acclimate to new genres over time.
Next, the design focus was narrowed down to: promoting personal development through expanding user’s musical horizons by introducing them to diverse music that differs from their current listening behaviour, fostering greater understanding of others and oneself. This design focus let to two different concepts. The first concept is ‘Discover More’, which adopts a similar approach as Discover Weekly, an automatically created playlist that gradually introduces users with new genres. The other concept is ‘Explore More’, a concept in which users are encouraged to actively explore new genres themselves. After evaluation it was decided to continue with Explore More. This concept was further developed and after evaluation of this concept, an improved version of the concept is proposed for the next cycle.
The concept highlights the gap between the vast musical landscape and the music the user listens to, creating awareness of their musical bubble and inspiring them to start exploring new music genres. Additionally, Explore More helps users gain deeper awareness and understanding of their own preferences. This is achieved with the help a guided self-reflection. Furthermore, the feedback on the reflection is utilized by the AI in selecting next genres and aims to align with the mood and taste of the user. After several exploration journeys, Explore More provides a recap—an opportunity to revisit the musical discoveries and providing insights into remarkable trends, such as specific elements that repeatedly spoke to the user, contributing to self-awareness.
Lastly, the report ends with additional suggestions that could be taken into consideration during the next cycle.
start=6.65 GHz and fstop=7.58 GHz, the tuning range is calculated to be 13 % with the Phase Noise@ 1 MHz(normalized to 10 GHz) varies from -128.1 dBc/Hz to -130.4 dBc/Hz and Figure of Merit varies from 188.0 dBc/Hz to 190.0 dBc/Hz, consuming average power of 95 mW and the fcorner is 250 kHz. Since the chip is still in fabrication and the final result only includes the simulation result. Further work involves the measurement and performance validation.","CMOS; oscillator; phase noise; voltage-controlled oscillator","en","master thesis","","","","","","","","2025-11-03","","","","Electrical Engineering","",""
"uuid:b6482ee5-9947-4b46-bd87-1b0091099635","http://resolver.tudelft.nl/uuid:b6482ee5-9947-4b46-bd87-1b0091099635","The Untapped Potential of Video in Architectural Design","Althuis, Jonas (TU Delft Architecture and the Built Environment)","van Dooren, E.J.G.C. (mentor); Hehenkamp, E.W.M. (mentor); Klitsie, L.M. (mentor); Delft University of Technology (degree granting institution)","2023","The Untapped Potential of Video in Architectural Design is a research and design project that explores the application of video-based techniques in the architectural design process. The project started with an experimental and applied research phase diving into video-based techniques at different stages of the design process, followed by my own design project where I could further apply and test these techniques. Due to the time-intensive nature of video production, it turned out to be difficult to use video at certain stages of designing, specifically the phase of generating and developing design ideas. In other phases, such as at the beginning and final representation, the use of video was very fruitful. The same pattern emerged when I continued to use video in my own design process; the application in the earlier research phase and the final representation phase of my design project, worked well. The use of video in the intermediate phase of generating and developing ideas less so. All of the videos that I made throughout the project, including most importantly the Research Film containing all of my research compiled together, as well as my final design videos, are available on my YouTube channel at the link below.","video; film; architecture; design process; design tools; port of rotterdam; material reuse","en","master thesis","","","","","","https://youtube.com/playlist?list=PL2ENgCey4Guf-TMdG_jBc-7YS8kSQGqeJ&si=njxY_ NBG1pD09bgg Link to my playlist of videos on Youtube, containing all of the videos I created throughout the research and design phase of my graduation project.","","","","","","Architecture, Urbanism and Building Sciences | Explorelab","","51.901946, 4.221340"
"uuid:47856dba-96d5-42d3-a31e-68492b893a23","http://resolver.tudelft.nl/uuid:47856dba-96d5-42d3-a31e-68492b893a23","Polymeric micelles and the Dy-166/Ho-166 generator: A study of the loading mechanism of Dy/Dy-166 and Ho-166 into PCL-b-PEO polymeric micelles for imaging and cancer treatment","Smit, Rinus (TU Delft Applied Sciences)","Denkova, A.G. (mentor); Wang, R. (mentor); de Kruijff, R.M. (graduation committee); Eelkema, R. (graduation committee); Delft University of Technology (degree granting institution)","2023","A radioisotope used in radionuclide therapy is Holmium-166 (Ho-166). The treatment effectiveness of Ho-166 could be improved by the use of a so called in vivo Dysprosium-166(Dy-166)/Ho-166 generator. The application of this generator is hindered by an effect called internal conversion (IC). This affect can arise after the decay of Dy-166 to Ho-166, which can cause separation of Ho-166 from its carrier.
Polymeric micelles might form a solution in the application of the Dy-166/Ho-166 generator in radionuclide therapy. The main goal of this thesis was to investigate and understand the loading mechanism of metallic species and polymeric micelles with a focus on the loading of Dy/Dy-166 and Ho-166.
It was found that it was not effective to load metallic species (Dy/Dy-166) as free ions or as solid precipitates. Loading metallic species as aqueous hydroxides showed to be crucial for achieving a good loading and high stability. The second goal was to study if polymeric micelles were able to retain Ho-166 inside their core under the effects of internal conversion. No additional losses of Ho-166 were found when Dy/Dy-166 and Ho-166 were loaded into the micelles. It was concluded that the PCL-PEO micelles prevented the loss of Ho-166 under internal conversion effects.","Radionuclide therapy; Polymeric micelles; Dysprosium-166; Holmium-166; Gallium-68; Loading mechanism","en","master thesis","","","","","","","","","","","","Applied Sciences","",""
"uuid:fc8270d1-057a-4ec6-9577-dd16417bc5b0","http://resolver.tudelft.nl/uuid:fc8270d1-057a-4ec6-9577-dd16417bc5b0","Hip implant force measurement: Design of an intraoperative hip joint 3-DOF force measurement system","Mol, Tessa (TU Delft Mechanical, Maritime and Materials Engineering)","Horeman, T. (mentor); Wei, J. (graduation committee); Hunt, A. (graduation committee); Delft University of Technology (degree granting institution)","2023","Achieving appropriate soft tissue tension around the hip joint is an important factor for achieving hip stability after Total Hip Arthroplasty (THA). Hip instability leads to dislocations, pain, and is a common reason for early revision surgery. The current soft tissue tension assessments available during surgery rely on experience, and dislocations occur twice as often after THAs performed by inexperienced surgeons compared to more experienced surgeons. This paper presents a new mechanism which measures and displays hip force in Three Degrees Of Freedom (3-DOF) during THA. A prototype measured axial and normal force components up to 75 N with a sampling frequency of 14.6 Hz, an accuracy up to 11 N, and a Root Mean Square Error (RMSE) of 4.0 N (axial) and 3.0 N (normal). Additionally, it measured the normal force direction with an accuracy up to 7.1∙10^(-2) π rad and RMSE of 7.1∙10^(-2) π rad. Data needs to be collected to build a predictive model which estimates the required hip force range and distribution to achieve a stable joint. When combined with such a predictive model, the proposed design is a promising assistive surgical tool.","hip arthroplasty; intraoperative; 3-DOF; hip implant; instrumented prosthesis; hip joint force","en","master thesis","","","","","","","","","","","","Biomedical Engineering","",""
"uuid:edfb694f-f016-4452-8086-f7ff79138069","http://resolver.tudelft.nl/uuid:edfb694f-f016-4452-8086-f7ff79138069","Model-Driven representation of the Infrarium Serious Game: From the Network of Puzzles concept to the Unified Modelling Language notation","Żurawska, Paulina (TU Delft Technology, Policy and Management)","Nikolic, I. (mentor); Bekebrede, G. (graduation committee); Delft University of Technology (degree granting institution)","2023","Serious Games can be used for many purposes, including studying complex, socio-technical systems. They are claimed to provide new opportunities by bringing different knowledge and fields of expertise to the table. Combined with simulations that allow for observation of the evolving infrastructure under deeply uncertain conditions, they have the potential to be an effective research tool. An example of such a serious game is Infrarium - an adaptive cyber-physical game that addresses the challenge of collective decision-making toward emission neutrality in the energy transition process within the port. The enormous space of paths that players could follow and the complexity of interactions available raise the question of whether it is possible to create such an intervention method that would allow for steering the gameflow. This research addresses this question by introducing the concept of a Network of Puzzles based on which the Infrarium model is built. After concept evolution was done while searching for a suitable tool, the System Modelling Language (SysML) was chosen. The game was successfully represented in the conceptual model that captures the system's complexity sufficiently enough to provide the coherent structure of the game within which the clarity and traceability of connections provide a design space for future development as a tool for shaping the game flow. The results are presented in the form of SysML diagrams followed by a discussion about SysML as a supporting tool in model-driven game design, within which the possibility of further vertical elaboration with requirements and limitations is justified. We have proven that further development of the game elements should not jeopardize the existing functional level of the model. The SysML model in the presented form could be used to design an intervention method to shape players' experience during gameplay.","Serious Games; Systems Modeling Language; Evolving Infrastructure; Decision making process; Complex socio-technical systems; Deep Uncertainty","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","Infrarium",""
"uuid:89dcc431-70d7-473e-8957-1310056142e3","http://resolver.tudelft.nl/uuid:89dcc431-70d7-473e-8957-1310056142e3","ASMITA modelling of the Wadden Sea with focus on the Groningerwad: Assessing how the Groningerwad will respond to accelerated sea level rise","Albers, Thomas (TU Delft Civil Engineering & Geosciences)","Wang, Zhengbing (mentor); Herman, P.M.J. (graduation committee); Huismans, Y. (graduation committee); Lodder, Q.J. (graduation committee); Delft University of Technology (degree granting institution)","2023","Some of the sediment which is eroded from the Dutch coast ends up in the Wadden Sea. Because of this the morphological development of the Wadden Sea is important, not only for the Wadden Sea itself but also for the maintenance programs of the adjacent coastlines. This is one of the reasons that the morphological development of the Wadden Sea is extensively studied. Some of these studies use the ASMITA model to make predictions of the morphological development with accelerating sea level rise. The Groningerwad is a part of the Wadden Sea consisting of a number of smaller tidal basins which has not been modelled with ASMITA. It has not yet been necessary to structurally nourish the coastlines surrounding the Groningerwad. However, as sea level rise increases it might well be possible that the coastal profiles surrounding the Groningerwad require nourishment. Therefore this thesis aims to study the Groningerwad with ASMITA to make a prediction of how the area will develop with accelerating sea level rise. To do this a morphological study is performed to determine the current morphological developments. This morphological study, based on available literature and bathymetry measurements of the area, finds that the Groningerwad is a highly dynamic area. It also determined the area and characterizing volume of each of the tidal basins, which have been used to set up the ASMITA model. For each basin in the Groningerwad an ASMITA model is set up using the information from the morphological study. The ASMITA model is used to make predictions for the development of the intertidal, channel and delta volumes of each of the Groningerwad its basins. The required parameters for the model have been derived from relevant formulas and the assumption that the Groningerwad is currently in a morphodynamic equilibrium. This was done because the time period for which bathymetrical measurements are available are to short to allow for a proper calibration procedure for these parameters. With this setup the ASMITA models show that all basins will lose intertidal sediment volume with rising sea levels. The larger basins of the Groningerwad also will not reach a new dynamic equilibrium state with large levels of sea level rise rate increase. When comparing these results to other basins in the Wadden Sea, it appears that the basins in the Groningerwad respond a lot slower than other Wadden Sea basins. Given the difference between the Groningerwad and the Wadden Sea and the fact that the time period over which bathymetrical data is available was to short to fully calibrate the model the recommendation is made to revisit this study when more data is available and it is possible to calibrate the relevant parameters.","ASMITA; Wadden Sea; Morphological development; Sea level rise; Groningerwad","en","master thesis","","","","","","","","","","","","Civil Engineering","",""
"uuid:7befc349-6f7b-48fd-bcb5-955504ec7530","http://resolver.tudelft.nl/uuid:7befc349-6f7b-48fd-bcb5-955504ec7530","Landscape Inside: The Indoor Green Condenser","Schippers, Tjalling (TU Delft Architecture and the Built Environment)","Bultstra, H.J. (mentor); Eckardt, H.F. (mentor); Corbo, S. (mentor); Meijer, A. (graduation committee); Delft University of Technology (degree granting institution)","2023","By bringing landscapes inside, this project is opening up nature to the people of Berlin, with a multi climate approach in the city. This prototype for condensed public green, is the starting point for creating a new modular building type with integrated urban gardening. Other Berlin neighbourhoods already have temporary communal gardens and commons as a central meeting place. With a permanent building as a centre, a neighbourhood garden’s position can be guaranteed for a long period of time.
In this indoor green condenser a combination of multiple green related functions and gardens can be enjoyed all year round. To make that possible, the site gets divided into acres through a grid of 10m by 10m. This grid is both suitable for landscape architecture as for open plan buildings with a column-structure. Every segment of the grid is then programmed with building functions or as part of the landscape around those functions. To every function one or more indoor green typologies are applied. These are then modified to fit in the grid. That way a patchwork of gardens and modules starts to take shape.
A great variety of landscaping and functions will give the users an experience that exceeds the lack of green in the city. The components of this prototype can be applied to a location where there is active demand for an expansion and condensation of greenspace in densifying cities, specifically in post-war neighbourhoods. It can be tailored to the proportions and the climate zones of the locations where the concept is applied. Thereby, Landscape Inside outlines an answer to the reality we all face in the unstoppable urbanisation of the future.","Indoor landscaping; Public condenser; green architecture; Public greenspace; community gardens; Densification; Privatization; Berlin","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences","","52.514962,13.432189"
"uuid:862cae57-1247-4134-8fed-6d9be7aaf086","http://resolver.tudelft.nl/uuid:862cae57-1247-4134-8fed-6d9be7aaf086","Cross-Sectional Analysis Of The Mechanical And Physical Properties Of Spruce Foundation Piles: An investigative analysis of moisture content, density, compressive strength, and modulus of elasticity across the cross-section of spruce foundation piles, with an emphasis on the predictive proficiency of micro-drilling methods","Lee, Michael (TU Delft Civil Engineering & Geosciences)","Pagella, G. (mentor); Mirra, M. (mentor); van de Kuilen, J.W.G. (mentor); Ravenshorst, G.J.P. (mentor); Gard, W.F. (mentor); De Vries, P (graduation committee); de Vries, P.A. (graduation committee); Delft University of Technology (degree granting institution)","2023","Summary
Numerous ancient historical constructions worldwide depend primarily on an extensive array of wooden foundation piles, as they are subject to loading conditions governed by the superstructure above. Wooden foundations transfer loads through a combination of compression and lateral resistance. The inherent strength of wood handles compressive forces, while stiffness and soil friction counteract lateral loads. Proper arrangement and maintenance ensure even load distribution. Careful design, wood quality, depth, and protective treatments are essential for longevity and load-bearing efficiency.
Amsterdam, the Netherlands' capital city, renowned for its rich artistic heritage, intricate canal infrastructure, and slender architectural dwellings, originated as a modest fishing hamlet that underwent remarkable development into a prominent global European city. During this urban transformation, less visible engineering elements, such as wooden foundation piles, were overlooked, despite their critical significance. In Amsterdam's historical core, the majority of structures including buildings, bridges, and quay walls, rely on these wooden supports. Noteworthy, the city estimates that 12 million such piles are still active. These structural components have consistently demonstrated economic efficiency and reliability. Nonetheless, the aging process affecting these foundations, with some dating back up to 500 years, introduces complexities when assessing their current load-bearing capacities and the ensuing reliability of the structures they support.
The lack of knowledge and inspection techniques of the mechanical and physical properties of these timber piles hinders a proper evaluation of the remaining life span of the foundations which could lead to possible irreplaceable structural damage to these structures. This body of research evaluates the physical and mechanical properties such as the actual moisture content, density distribution, compressive strength, and modulus of elasticity through the cross section of Spruce (Picea abies) foundation piles. Therefore, the overarching research question has arisen:
“How do the variations of mechanical and physical attributes manifest across the cross-sectional profile of both degraded and non-degraded spruce foundation piles and how can micro-drilling techniques be utilized to assess these characteristics?“
This will be achieved by means of small-scale compressive experimental testing of five prisms extracted from each cross-section (3 separate locations along the length of the pile) of foundation piles never driven into the soil and piles that were retrieved under bridges in the historical centre of Amsterdam that were planned to be demolished. These aforementioned retrieved piles had a service life between 100 years and 300 years, always under the water table, presenting mechanical degradation due to loading over time and in addition possible bacterial degradation of the cross-section peripheral regions.
Initially, micro-drilling techniques were employed to ascertain the drilling amplitude. This step served to assess the initial quality of the wood under examination. Additionally, it aided in identifying specific points of interest for specimen extraction, including degraded wood in the peripheral regions, sound wood in the internal section, and the pith. Subsequently, the acquired data underwent thorough analysis. This analysis, combined with the micro-drilling measurements, enabled an assessment of the potential applicability of drilling amplitude in predicting the mechanical and physical properties of the pile. This sequential approach ensured a systematic and scientifically rigorous evaluation of the wood's characteristics and its implications for pile performance. The investigation was conducted to enhance the understanding of the structural performance and material characteristics of spruce foundation piles, while also evaluating the applicability of micro-drilling methods as a predictive tool in engineering assessments...
The study commenced with an extensive literature review, drawing from a diverse range of sources, including reviews, offshore guidelines, research papers, and expert interviews. The literature review was conducted to enhance the understanding of the use of helical piles in the offshore industry, encompassing their fundamental characteristics, current applications, and potential contributions. For this investigation, a Tension Leg Platform (TLP) featuring a 15 MW wind turbine, engineered by Heerema Engineering Solutions (HES), was employed. Time-domain simulations, accounting for environmental conditions, were carried out using the OrcaFlex software. These simulations led to the determination of the mooring line tensions, with the maximum value identified as the design load case. During the helical pile geometry optimization process, which focused on maximizing uplift capacity, it was established that a single helical pile in dense sand can achieve a maximum uplift capacity of 7.91 MN, while taking into account geotechnical, structural, and installation constraints. As a result, considering the significant uplift capacity demands of TLPs, it is essential to employ helical pile grouping, necessitating a minimum of four helical piles. Consequently, the design of the helical pile group anchors confirms their ability to meet the uplift and lateral capacity requirements of TLPs. Furthermore, the exploration of variations in equipment, steel strength, helical pile geometry, and soil conditions has yielded promising results. It is important to note that achieving the required installation depth for these group anchors involves a significant force and torque during the installation process, presenting potential challenges. Consequently, the development of equipment capable of meeting these installation requirements is vital for ensuring the feasibility of these helical pile group anchors.
The performance of helical pile group anchors was analysed from economic, technical, and environmental perspectives, with a comparison to suction and driven pile anchor concepts. The economic evaluation showed that the estimated total costs for the 4-pile helical group anchor, utilizing a singlepile installation method, are notably higher when factoring in the costs related to developing helical pile equipment, making it less financially attractive compared to the developed suction and driven pile anchor concepts. However, when excluding these equipment costs, the 4-pile helical group anchor ranked as the second-most financially attractive option, regardless of the installation technique, with only the single driven pile anchor being less expensive. Notably, it was discovered that, in a scenario where structural, geotechnical, and installation constraints are disregarded, the single pile helical anchor emerges as the most financially attractive among all anchor types, even surpassing the single pile driven anchor. This suggests that overcoming challenges related to scaling up helical pile dimensions, like enhancing their structural integrity, and reducing installation requirements through innovative designs, could make the use of fewer piles in a helical pile group anchor a feasible choice. In addition to these quantifiable factors, helical piles offer the advantage of a low-noise installation method, which becomes increasingly important due to the growing noise disturbance legislation in certain regions. Furthermore, their adaptability to various ground conditions through flexible installation techniques makes them a convenient choice for sites with limited access or specific inclination requirements...
This research aims to create a machine learning (ML) method that categorises reconstruction kernels from various vendors into groups based on their sharpness. This categorisation will rely on image features extracted directly from real patient scans with diverse scan parameters.
Two distinct methods were explored to achieve the objective, each utilising different image features and applied to a selected subset of the CT datasets from the National Lung Screening Trial (NLST) and the Lung Image Database Consortium image collection (LIDC-IDRC). The first method focused on noise features, specifically the standard deviation (SD) of the most homogeneous region of interest (ROI) to measure CT scan noise magnitude and the central frequency (CF) derived from the noise power spectrum (NPS) to represent scan noise texture. These noise features were used as input for a linear support vector machine (SVC), creating the $SVC\_noise$ model. Additionally, an approach that incorporated radiomic features was explored. These radiomic features were extracted from 30-pixel-sized ROIs selected from the ten most homogeneous patches. The radiomic feature sets were then used to train a random forest classifier (RFC), creating the $RFC\_radiomics$ model. The models were evaluated using accuracy and Receiver Operating Characteristic Area Under the Curve (ROC AUC) scores. McNemar’s test was employed to determine if one model significantly outperformed the other. Evaluating the categorisation results presented a significant challenge due to the lack of a ground truth. Consequently, a subset of the smoothest and sharpest kernels from each manufacturer was selected to train, validate, and test the models. Subsequently, the models were applied to the remaining kernels, and ground truth was established for each kernel by identifying the predominant class within each one.
Both models demonstrated strong performance when applied to 270 cases featuring 37 distinct reconstruction kernels. The $SVC\_noise$ model achieved an impressive ROC AUC score of 0.97 and misclassified eight of the 270 cases based on its smooth and sharp categorisation definition. The $RFC\_radiomics$ model achieved a slightly lower ROC AUC score of 0.96, with ten misclassifications out of the 270 cases. McNemar’s test indicated that the difference in performance between the two models was not statistically significant. Moreover, the ground truth approach, applied manually, resulted in only one inconsistent kernel between the two models; specifically, the determination of the ground truth of kernel “$B50s$” differed.
In summary, the $SVC\_noise$ and $RFC\_radiomics$ models displayed promising performances, with neither significantly surpassing the other. Both models exhibited the capacity to effectively identify sharpness-related patterns within the two classes while disregarding the noise caused by variations in scan parameters and patient characteristics in real patient data. This capability offers valuable insights that can bridge the divide between research and clinical applications. However, it is important to note that the findings from this research are preliminary, and caution should be exercised when applying these results to broader contexts, including newer reconstruction kernels and techniques.
To improve the accuracy of the PMI Academic Medical Centre (AMC) in Amsterdam, TU Delft, the Dutch Forensic Institute and the Dutch police initiated the Therminus project. Using the Wilks Model [1]with specialised equipment can increase the accuracy of the PMI by up to a 15-minute margin of error under ideal circumstances and up to 3.2 hours under non-ideal circumstances.
For the Wilks model, the weight of the deceased remains an important input and the QuickScale was developed as a specialised tool to provide this information to forensic investigators at the crime scene. This report contains the development of the second iteration of the QuickScale, the QuickScale 2.0. Objectives of this development were:
1. To Finish the QuickScale prototype, design the modules needed for building in the electronics and for adding user-friendly, intuitive controls.
2. To design and conduct usability studies with forensic investigators and use the obtained information to further improve the QuickScale construction, electronics and usability.
Using a design analysis and usability engineering approach for the QuickScale design and user interface respectively. The QuickScale design was calibrated, and validated and possible improvements were identified. Three different user interfaces were developed and usability studies were conducted for groups of students and forensic investigators. New design requirements were derived from both the design analysis and usability studies.
The resulting QuickScale 2.0 design incorporated the user interface that resulted in the least user errors. It met 27 out of the total 30 design criteria and contains:
• An ambidextrous user interface.
• Correcting springs for the non-linearity of the load cell when measuring weights below 20kg.
• Handlebars with improved grip which can easily be extended to accommodate more users.
• Safety labels with an abbreviated guide on the field use and stickers indicating the controls
The un-met design criteria were an indicator of remaining battery life and the possibility that both units can display a difference in weight larger than 0.5 kgs, especially at the start of weight measurements. As this design still needs to be produced, it needs to be tested and evaluated. Special care should be taken when calibrating the QuickScale 2.0 and altering the calibrating method might be necessary. Furthermore, it is recommended to integrate the QuickScale 2.0 with other Therminus equipment in future evaluations.
All in all the QuickScale 2.0 is a user-oriented step toward more accurate post-mortem interval estimation.
This research underscores the importance of financial literacy within design innovation. By enhancing designers’ financial competence, it shifts their focus from exploratory innovation towards strategic innovation. This transition involves combining elements of exploratory, design, and viable innovation, aligning innovation efforts with long-term project goals. This shift becomes possible by leveraging financial knowledge, resulting in choices that provide a competitive advantage, adaptability to changing market conditions, and entry into new markets (Lusardi & Messy, 2023).
While acknowledging the organisational influence on financial literacy, this research focuses on its significance at a project level, particularly during the fuzzy front end of innovation. The study adopts the double diamond approach, a popular process among design practitioners (Brown, 2009; Martin, 2009; Liedtka, 2014), to evaluate financial literacy's impact on the innovation process.
The culmination of this research is the Design Innovation Viability (DIV) Dashboard, an innovative tool that guides designers and professionals through the intricacies of financial literacy in design innovation. It features a series of 16 learning modules, each focusing on specific components of financial literacy, and provides a structured learning assessment to gauge one's financial competence, by use of Bloom’s Taxonomy.
The implications of this work are substantial, equipping designers with comprehensive financial literacy, enhancing design innovation competence, and enabling effective stakeholder communication. However, it is important to recognize the study’s limitations. it is essential to further explore and expand the understanding of financial literacy in design innovation. Moreover, a more comprehensive framework for presenting a Value Case or Business Case in the final stages of design projects is needed (Duréndez et al., 2023).
In summary, this research pioneers integrating financial literacy with design innovation, making financial competence a fundamental element. The findings resonate with the importance of financial literacy for designers and professionals, reinforcing the significance of making informed financial decisions, assessing viability, and fostering strategic innovation. This work serves as an inspiration for future research in the domain of financial literacy in design innovation, ultimately advancing design education and practice.","Financial literacy; design innovation; learning module; innovation framework; viability; Bloom's taxonomy; design thinking; strategic design; Finance innovation; finance; design education","en","master thesis","","","","","","https://www.figma.com/proto/AswUllKnTzTKUAC8lAjylW/Graduation-Report?page-id=401%3A2320&type=design&node-id=424-1571&viewport=219%2C429%2C0.02&t=nzTc9IK4h4F5YUZc-1&scaling=scale-down&mode=design Design Innovation Viability (DIV) Dashboard - Learning Modules Made with Figma prototyping function.","","","","","","Strategic Product Design","",""
"uuid:4b8ed913-ce28-4b86-829f-6ac8596644bc","http://resolver.tudelft.nl/uuid:4b8ed913-ce28-4b86-829f-6ac8596644bc","A Door-to-Door Multimodal Simulation-Based Framework for the Integration of Advanced Air Mobility Design and Operations","Berger, Menno (TU Delft Aerospace Engineering)","Sharpanskykh, Alexei (mentor); Shiva Prakasha, Prajwal (graduation committee); Naeem, Nabih (graduation committee); Delft University of Technology (degree granting institution)","2023","This study presents the development of a multimodal System of Systems (SoS) framework, to assess the impact of top-level aircraft requirements in providing advanced air door-to-door mobility. The field of Advanced Air Mobility (AAM) is rapidly evolving, and while current research assesses these vehicles from
both aircraft design and operational perspectives, a system of systems perspective combining both domains is required to find the best overall vehicle design and operational concepts. In this work, aircraft design is assessed by its effectiveness in the operating environment, considering the perspective of the stakeholders of passengers, operators and European policy makers. This is done through combining aircraft design in an agent-based multimodal simulation framework, covering both surface and air transport. Doing so allows us
to analyse the impact of top-level aircraft requirements on door-to-door travel time, AAM mode share and energy consumption per passenger. Using this framework, it was found that the most impactful parameter on AAM utilization is the passenger’s mean value of time. Additionally, several SoS effects could be traced to changes at the agent level, where giving passengers more travel options leads to 16% higher AAM adoption, but at shorter (-8.2 %) average trip distances due to preferences for shorter and cheaper flights. Lastly, the
relevance of considering operations for aircraft design was seen, where the best theoretical design for energy efficiency performed 10% worse than the best design considering operations, as the average mission profile in operation is different to the designed profile. In conclusion, the developed framework demonstrates the need for combining operations and aircraft design, and can be used to explore the best concepts in both fields.","","en","master thesis","","","","","","","","2023-11-15","","","","Aerospace Engineering","",""
"uuid:d43d12e0-28f9-4a5e-9069-f14eea3a0a5f","http://resolver.tudelft.nl/uuid:d43d12e0-28f9-4a5e-9069-f14eea3a0a5f","Nature-positive Architecture: A Regenerative Design Approach of a Winery in the Quarry of the St. Pietersberg","Verduin, Liam (TU Delft Architecture and the Built Environment)","Parravicini, M. (mentor); Koskamp, G. (graduation committee); Tillie, Nico (graduation committee); Delft University of Technology (degree granting institution)","2023","Sustainability in its development is increasingly focusing on nature. However, this research shows that through positive development, benefits are not only gained in nature, but are actually viewed as a common good. From this emerged regenerative development and design, in which there is a judgement from a whole system perspective. Through the knowledge of place, a strategy is first developed within the design process, in which oak regeneration can respond to the respective site patterns. This knowledge should then be used to design in harmony with the larger patterns of place. This is achieved through a partnership between the place (as a living being) and other various living systems. Herein, such a partnership is presented between place, humans and oak forest regeneration. This partnership brings forth new activities and growth through co-evolution, and is made permanent by bridging with viticulture. The regeneration of wood is passed down over several generations, using it not only as a building material, but also with the manufacture of wine barrels. In doing so, this research shows how this material works and is produced, and what other uses, if any, are available at the time the material depreciates.","Local resources; Nature-positive; Renewable materials; Regenerative design; Oakwood; Wine barrels; Winery","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Architectural Engineering","","50.824213,5.682589"
"uuid:3a2dbc59-f4ea-4223-ad42-802b55ee5e44","http://resolver.tudelft.nl/uuid:3a2dbc59-f4ea-4223-ad42-802b55ee5e44","The (Re-)Model Market: Street Food Market as Urban Restorative Entities","Dosheva, Ana (TU Delft Architecture and the Built Environment)","Fokkinga, J.D. (graduation committee); Kuijper, J.A. (graduation committee); Alkan, A.S. (mentor); Delft University of Technology (degree granting institution)","2023","Street Food markets have been a key ingredient of the urban life for centuries. In many cases the direction and intensity of urban expansion was strongly reliant on the emergence of the street food market and vice-versa. These link between the two has been inevitable historically until now and will probably continue as such in the future. However, the city changes on daily basis and, being a reflection of it, so does the market. While the former speeds up, becomes more erratic and stressful, the latter slows down, transforms into a space of gather and pleasure, exceeding beyond its food trade function. Therefore, their relationship also changes, with the market becoming an instrument of healing for both the city and the individual. London, being a distinct example of the contemporary megapolis and having a key role in the historic evolution of street food markets, was chosen as a test bed for the research to untangle what is the situation of the street food market today as an urban and experiential entity and question its future potentials.","street food; market; urban well-being; restorative environments; food in the city; nature in the city; material cycles; urban behaviours; affective atmospheres","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Architectural Design Crossovers","",""
"uuid:3ed86d63-8466-4ed7-a66f-1d7c7ee78003","http://resolver.tudelft.nl/uuid:3ed86d63-8466-4ed7-a66f-1d7c7ee78003","Representations of DNA Sequence Context and Mutational Spectra for Prediction of Repair Deficiencies","Borg, Jonathan (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Pattern Recognition and Bioinformatics)","P. Gonçalves, Joana (mentor); Martinez, Jorge (graduation committee); Seale, C.F. (graduation committee); Delft University of Technology (degree granting institution)","2023","Double-strand break (DSB) repair is a critical cellular process which repairs breaks in both strands of the DNA double helix. Different repair mechanisms are tasked with repairing such breaks. Predicting deficiencies in repair mechanisms has been widely used for therapeutic purposes, such as targeting cancer cells that have specific DNA repair deficiencies. DSB repair, however, is not error-free, resulting in mutations. These mutations are also influenced by the DNA sequence surrounding the break site. To the best of our knowledge, sequence representations have not been considered when predicting DNA repair deficiencies. We hypothesise that higher-order information can be extracted from sequence representations. In this study, we research the problem of predicting Non-Homologous End Joining (NHEJ) repair deficiencies. Initially, we evaluate how accurately we can predict NHEJ repair deficiency using only the mutational outcome frequencies (mutational spectra). Afterwards, we examine how combining mutational spectra with representations of the sequence surrounding the break site can improve the prediction of NHEJ repair deficiency. We demonstrate that adding DNABERT sequence representations to mutational spectra features significantly improves prediction accuracy from 94.44% to 96.12%. We also show that even simple sequence representations, such as 1-mer frequencies, can lead to significant improvements. Our findings highlight the importance of including sequence representations with mutational spectra in repair deficiency prediction.","DNA Double-Strand Break; Repair Pathway Deficiency; Mutational Spectra; DNA Sequence Representation","en","master thesis","","","","","","","","","","","","Computer Science | Bioinformatics","",""
"uuid:5757907b-e786-4775-b085-694ecf8c9e3b","http://resolver.tudelft.nl/uuid:5757907b-e786-4775-b085-694ecf8c9e3b","A Symbiotic Architecture along the edge zone of the Marmara Sea: A shift towards an ecocentric architecture fostering a deeper connection between humanity and nature","Wientjes, Carmen (TU Delft Architecture and the Built Environment)","Rommens, O.R.G. (mentor); Koorstra, P.A. (mentor); Koskamp, G. (mentor); Delft University of Technology (degree granting institution)","2023","In the urban and coastal region surrounding the Marmara Sea, a detachment between human life and the ocean is emerging that seems primarily caused by the consequences of post-industrial anthropogenic processes. The effects are seen in the form of a mucilage plague in the waters, posing a threat to marine life, and thereby emphasizing the urgent need for intervention. This project, strives to unveil the interplay between the natural dynamics of the Sea of Marmara and our human relationship with this vital, pulsating ecosystem.
At its core, the architectural intervention proposes a symbiotic architecture, positioning itself as a mediator that is bridging the widening gap between humanity and nature: An eco-centric approach that dissolves the conventional demarcation lines between land and water. By showcasing the various activities occurring in our oceans, the project seeks to enhance the visible connection and experience, developing a strengthened collective awareness of the ecological body we are part of. A carefully curated journey through an architectural landscape aims to create a deeper understanding of the interconnectedness and cyclical rhythms inherent to the surrounding landscape. Drawing from the insights of J. Bloomer, who challenges the conventional notion of coastlines as mere edges, the project embraces the concept of interrelational edge zones. Here, the terrain is seen not as a binary transition but as a dynamic and continuous process.
In essence, the project aspires to not only address the immediate ecological concerns surrounding the Marmara Sea but also to spark a shift in our collective consciousness. By connecting architectural innovation with ecological principles, it strives to establish a harmonious co-existence between humans and the natural world, fostering a deep ecological awareness that transcends traditional boundaries.
hyperspectral mineral exploration method in underground environments is needed. This study configures a Cubert X20P hyperspectral camera (VNIR) and VLP16 LiDAR on the versatile Boston Dynamics Spot robot, creating a multi-sensor robotic platform for data acquisition in underground mining environments. A data workflow is proposed and applied to the granite greisen rocks of the Zinnwald/Cinnovec mine (Germany). Combining hyperspectral and geometric data provides unique 3D hypercloud results interpreted for mineral
and structural features. Hyperspectral analysis successfully identifies iron and clay minerals along with multiple vein and fault structures. A remote mineral exploration method in underground mines significantly improves safety by keeping the operator away from hazardous areas. The proposed platform and workflow show potential to contribute to underground mineral exploration, especially if future improvements in data quality and autonomous capabilities are made.","Hyperspectral Imaging; Remote Sensing; Robotics; Mining; Exploration; Geology; LiDAR; Sensors; Mineral identification","en","master thesis","","","","","","","","","","","","Applied Earth Sciences | European Mining Course","",""
"uuid:0be72865-8064-4120-8103-c57b1321a3f0","http://resolver.tudelft.nl/uuid:0be72865-8064-4120-8103-c57b1321a3f0","Embedding design practices in local government: A case study analysis","Kim, A. (TU Delft Methodologie en Organisatie van Design)","Lloyd, P.A. (promotor); Mulder, I. (promotor); van der Bijl-Brouwer, M. (copromotor); Delft University of Technology (degree granting institution)","2023","Design approaches are increasingly being employed by governments worldwide to address public service and policy issues. This book explores the evolution of these design practices within the context of local government, shedding light on the value they can create and how they become stabilized in six local government organizations.","Design for policy; Local government; Public sector innovation; Design management","en","doctoral thesis","","978-94-6366-758-6","","","","","","","","","Methodologie en Organisatie van Design","","",""
"uuid:62a12e6d-d7d2-4244-8df9-89413ec133da","http://resolver.tudelft.nl/uuid:62a12e6d-d7d2-4244-8df9-89413ec133da","Development of Nickel-Titanium Shape Memory Alloys via Laser Power Bed Fusion","Zhu, Jia-Ning (TU Delft Team Vera Popovich)","Popovich, V. (promotor); Hermans, M.J.M. (promotor); Delft University of Technology (degree granting institution)","2023","Shape memory alloys (SMAs), such as nickel-titanium (NiTi) alloys or Nitinol, possess remarkable properties, including superelasticity and shape memory effects, which are attributed to the reversible martensitic transformation. However, traditional manufacturing of NiTi SMAs is challenging due to its high ductility and reactivity, which limits NiTi applications to simple geometries. In this context, laser powder bed fusion (L-PBF), an additive manufacturing technique, emerges as a promising solution capable of overcoming these limitations and introducing the concept of four-dimensional (4D) printing. This approach enables the creation of morphing shapes that can be activated by external stimuli, such as heat or stress, particularly beneficial for SMAs.","Nickel-Titanium; shape memory alloys; additive manufacturing; laser powder bed fusion; superelasticity","en","doctoral thesis","","978-94-6469-631-8","","","","","","","","","Team Vera Popovich","","",""
"uuid:3934e1cb-eb44-498c-86d5-79e0420b2db0","http://resolver.tudelft.nl/uuid:3934e1cb-eb44-498c-86d5-79e0420b2db0","Detection of Distractions in Human Manual Control Tasks Using Machine Learning","Li, David (TU Delft Aerospace Engineering)","Mulder, Max (mentor); Pool, D.M. (mentor); Delft University of Technology (degree granting institution)","2023","Technological devices are ubiquitous, think of for example smartphones and in-vehicle information systems. Both can contribute towards distracted driving where the visual field of the human controller is shifted away from the primary control task. In this paper a neural network model is trained using the InceptionTime architecture and used to detect distractions in pursuit and preview tracking tasks. For this purpose an experiment has been designed to collect data in which participants are distracted using a visual distraction called the Surrogate Reference Task (SuRT). It was found that distractions are easier to detect in tracking tasks with pursuit displays instead of preview displays. This is because in preview displays the future target trajectory is shown to the human controller, resulting in a lower tracking error compared to pursuit displays. Apart from the tracking error, the InceptionTime neural network was also trained using the time-series data of the control input and system output. Important characteristic of distracted data found were a reduced control input and higher tracking errors, which may have helped in detecting distractions. The classification models were able to predict data samples correctly with an accuracy of 80.78% and 61.66% in pursuit and preview tracking tasks with distractions, respectively. Lastly, individualised models showed better performance when compared to 'one-size-fits-all models'. Results show clear opportunities for applying neural network models in real-time to detect distractions for increasing safety in human operated machines.","Cybernetics; Manual Control; Tracking Task; Detection of Anomalies; Eye Tracker; Machine learning","en","master thesis","","","","","","","","2025-11-01","","","","Aerospace Engineering","",""
"uuid:b245d49c-ff64-40cf-9b8d-1b83083df7fd","http://resolver.tudelft.nl/uuid:b245d49c-ff64-40cf-9b8d-1b83083df7fd","Modelling reservoir dynamics in a data scarce semi-arid region","van Welsenes, Erik (TU Delft Civil Engineering & Geosciences)","Hrachowitz, M. (mentor); van de Giesen, N.C. (graduation committee); Zuijderwijk, Michel (graduation committee); Te Witt, Daan (graduation committee); Delft University of Technology (degree granting institution)","2023","In order to evaluate measures to increase water availability in and around reservoirs it is necessary to have reliable reservoir water storage models. For that reason, it is necessary to assess the validity of these models. The aim of this research is to do this assessment of two models in data scarce semi- arid regions. The Nakamb ́e catchment is used as a case study. The study covers important aspects of hydrological modelling, such as model input (data) selection, hydrological model choice, calibration, model performance testing, parameter sensitivity, and reservoir water storage simulation.
For the selection of the optimal model forcing data diverse precipitation products are reviewed: CHIRPS, ERA5, and local measurements. Among the evaluated datasets, CHIRPS emerges as the superior choice validated against the local measurements. With respect to the potential evaporation, the combination of ERA5 and local measurements results in the most suitable potential evaporation data, leveraging the temporal and spatial aspects of ERA5 and the absolute values of the local measurements.
Comparing a lumped hydrological model (HBV) with a distributed model (SBM Wflow) in simulating river discharge reveals that the HBV model outperforms its counterpart in simulating discharge. This contrast in performance is attributed to potential overparameterization in the Wflow model, coupled with the complexities of parameter estimation in data-scarce areas. The HBV model, while bearing simplifications, benefits from a more comprehensive calibration process. The model performance is strongly influenced by the calibration efficiency, where the significantly shorter simulation time of the HBV model facilitates an extensive Monte Carlo sampling-based calibration, in contrast to Wflow’s time consuming manual parameter adjustment.
Additionally, the sensitivity analysis showed that in the HBV model, the parameters affecting actual evaporation are the most sensitive one. This emphasizes the importance of accurately simulating this component for the proper model performance. The Wflow model exhibits strong equifinality due to the many parameters within the model. The complexity of this model made it impossible to test all parameters and therefore only some parameters are tested.
Both reservoir water storage models studied, the HBV Reservoir Water Storage Model (HBV RWSM) and the Wflow reservoir module, can effectively simulate reservoir water storage fluctuations, although they differ in how the components are calculated. Due to data limitations, it is impossible to determine which, if any, of the models is correct. However, based on the downstream discharge the HBV RWSM displays a more promising performance.
In conclusion, the HBV model outperformed the SBM Wflow model in simulating discharge due to its simplicity and ease of calibration. Sensitivity analyses highlighted the significance of accurately representing actual evaporation. Both water balance models, the HBV RWSM and the Wflow reservoir module, performed similarly concerning the NSE values. The fluxes contributing to the water balance in the two reservoir water storage models differ significantly. The lack of data on these fluxes makes it impossible to determine which models performs best. Data limitations remain a significant hurdle in model evaluation, emphasizing the need for additional data collection, particularly upstream and downstream of the reservoir, to enhance reliability and reduce uncertainties.
This thesis is motivated by the societal demand for trustworthy Al, by the propensity of Al systems to be biased, and consequently by the need to detect and mitigate bias in diverse Edge Al applications. To address this need, this thesis develops design patterns for detecting and mitigating bias in the development of Edge Al systems. The design patterns present a generalisable approach for capturing established practices to detect and mitigate bias in machine learning. They make this knowledge readily accessible to researchers and practitioners that develop Edge Al, but who have limited prior experience with detecting and mitigating bias.","Edge AI; Edge Intelligence; Trustworthy AI; Responsible AI Design; Bias; Fairness; Design Patterns; Speech Technology; Speaker Verification; Keyword Spotting","en","doctoral thesis","","978‑94‑6419‑932‑1","","","","","","","","","Information and Communication Technology","","",""
"uuid:b3d264ce-e7dc-4e67-b0e1-94f3cc7831ca","http://resolver.tudelft.nl/uuid:b3d264ce-e7dc-4e67-b0e1-94f3cc7831ca","Geomechanical Study of Underground Hydrogen Storage","Ramesh Kumar, K. (TU Delft Reservoir Engineering)","Hajibeygi, H. (promotor); Jansen, J.D. (promotor); Delft University of Technology (degree granting institution)","2023","With the rise of renewable energy and the drive to achieve net-zero emissions, energy storage has become a crucial component of the energy sector to address the challenges of intermittency. The vast subsurface environment offers significant storage potential, capable of accommodating terawatt-hour (TWh) capacities. One approach to leverage this storage capacity involves converting renewable energy into hydrogen and storing it underground within salt caverns and depleted porous reservoirs. This stored hydrogen can then be utilized as needed. However, this cyclic injection and production of hydrogen will exert repeated stress on the subsurface, resulting in periodic changes in pressure.
One critical aspect that requires investigation for the safe storage of hydrogen (H2) is the field of geomechanics, which becomes essential in both salt caverns and depleted reservoirs. To gain a better understanding of this, a comprehensive review of the geomechanics involved in underground hydrogen storage was conducted to examine existing knowledge and identify research gaps. To delve deeper into the influence of geomechanics, particularly regarding the inelastic creep deformation of rocks in salt caverns and depleted porous reservoirs, numerical simulations were employed. Given the potential costliness of fine-scale simulations, multiscale simulations were carried out using algebraic multiscale methods. Constitutive models were utilized to analyze deformation patterns in and around the reservoir, assessing their impact on subsidence or uplift.
In order to further comprehend the effects of cyclic loading on rocks, constitutive models were developed based on extensive experimental data obtained from sandstone rocks subjected to long-term stress conditions. These models aided in uncovering the underlying physics of rock behavior when exposed to different stress regimes during prolonged cyclic loading. Subsequently, these models were integrated into finite element method (FEM) simulations to observe their impact on field-scale scenarios, with a synthetic Bergermeer case study serving as an example.
To enhance the computational efficiency of multiscale methods, unsupervised machine learning techniques were applied to optimize the formation of computational grids, utilizing graph theory techniques such as Louvain and random walk algorithms. These optimized grids were then compared with the grids generated from METIS to evaluate the computational performance of pressure solvers in a commercial scale simulator.","","en","doctoral thesis","","978-94-6366-759-3","","","","","","2023-11-01","","","Reservoir Engineering","","",""
"uuid:4d4a1cfa-836f-415f-a255-84d49a4797a0","http://resolver.tudelft.nl/uuid:4d4a1cfa-836f-415f-a255-84d49a4797a0","Shearography non-destructive testing and defect characterisation of thick composite structures","Tao, N. (TU Delft Structural Integrity & Composites)","Benedictus, R. (promotor); Groves, R.M. (promotor); Anisimov, A. (copromotor); Delft University of Technology (degree granting institution)","2023","THICK composite materials, e.g., thickness of more than 50 mm, are increasingly being used across diverse industry sectors owing to their significant advantages of weightsavings, superiormaterial properties and load-carrying capability. These materials tend to be adopted in safety-critical applications such as large primary or secondary load-bearing structures, where mechanical failures would result in serious consequences. However, various defects and damage may occur in thick composites that endanger structural integrity and safety severely. Hence to improve the maintenance, safety and reliability of these structures, it is crucial to develop inspection methods capable of defect detection and characterisation for composite structures of significant thickness. To date, the nondestructive testing and evaluation (NDT&E) of thick composite structures still remain an urgent challenge due to their material and structural complexity, significant thicknesses, and the presence of various manufacturing and in-service defects....","Digital shearography; Speckle interferometry; Strain characterisation; Thick composite inspection; Composite laminates; Non-destructive testing and evaluation; Defect detection and characterisation; FEM-assisted inspection; Spatially and temporally modulated heating","en","doctoral thesis","","978-94-6384-499-4","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:94f225e8-823e-47b6-a3c7-d3c9846960e2","http://resolver.tudelft.nl/uuid:94f225e8-823e-47b6-a3c7-d3c9846960e2","Climate Change and Fish Farming: Venetian “Fish Valleys” as a Design Device for Coastal Adaptation and Mitigation","Cipriani, L. (TU Delft Landscape Architecture); Destro, Alessandro (Rete Ferroviaria Italiana (RFI))","","2023","Beginning in the fourteenth century, along the northeastern Italian coastline, Venetians began to create a series of hydraulic structures called “fishing valleys,” which combined aquaculture production with lagoon and seawater management. According to the current scenarios provided by the Intergovernmental Panel on Climate Change, the coastal areas, where many historic fish farms still stand, will inevitably be affected by the rise in sea level. To be preserved, coastlines will require some sort of water defense or possibly a managed retreat. Can we redesign traditional fish-farm systems as climate, economic and environmental adaptation devices? Through a series of design scenarios, this contribution explores how traditional fish farming can help redefine the territorial scale by addressing climate change and reviving existing production systems.","Climate Change Adaptation; Climate Change Mitigation; Fish farms; Venice lagoon","en","journal article","","","","","","","","","","","Landscape Architecture","","",""
"uuid:d1c6502f-2240-4d91-be93-0c761eee67ee","http://resolver.tudelft.nl/uuid:d1c6502f-2240-4d91-be93-0c761eee67ee","Shape-locking in architected materials through 3D printed magnetically activated joints","de Jong, P.H. (TU Delft Support Biomechanical Engineering; TU Delft Biomaterials & Tissue Biomechanics); Salvatori, Y.S. (University of Genova); Libonati, F. (University of Genova); Mirzaali, Mohammad J. (TU Delft Biomaterials & Tissue Biomechanics); Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics)","","2023","Shape morphing is the ability of objects to adapt to different shapes and reduce stress concentrations through increased contact area. This is a common trait of natural and engineered objects and has several applications in, among others, soft robotics and orthopedic implants. Shape morphing is achieved through flexible materials or rigid components with either kinematic or compliant joints. An additional step, namely shape locking, is needed for sustained load support. Activation of a locking mechanism can be done with any energy, among which magnetism is one. Here, we present the implementation of a magnetic locking mechanism for kinematically deformable metamaterial structures that maintain shape and support loads upon locking. The structure consists of 3D printed rigid magnetic and non-magnetic components connected by hinges. We created several prototypes of the proposed designs using two additive manufacturing methods (i.e., material extrusion and multi-material jetting) and demonstrated its application in a closed-loop grid for arbitrary shapes. Moreover, we characterized the performance of the prototypes using mechanical tests and multibody kinematic system simulations. This work highlights the viability of the locking concept and provides design considerations for future applications. Further improvement and optimizations are needed for increased efficiency and effectiveness.","3D printing; Kinematic fixation; Locking mechanism; Magnetism; Shape morphing","en","journal article","","","","","","","","","","","Support Biomechanical Engineering","","",""
"uuid:461cb324-0498-4ee5-99f7-919bef9c78cb","http://resolver.tudelft.nl/uuid:461cb324-0498-4ee5-99f7-919bef9c78cb","Prediction of oil and gas pipeline failures through machine learning approaches: A systematic review","Al-Sabaeei, Abdulnaser M. (Universiti Teknologi Petronas); Alhussian, Hitham (Universiti Teknologi Petronas); Abdulkadir, Said Jadid (Universiti Teknologi Petronas); Jagadeesh, A. (TU Delft Pavement Engineering)","","2023","Pipelines are vital for transporting oil and gas, but leaks can have serious consequences such as fires, injuries, pollution, and property damage. Therefore, preserving pipeline integrity is crucial for a safe and sustainable energy supply. The rapid progress of machine learning (ML) technologies provides an advantageous opportunity to develop predictive models that can effectively tackle these challenges. This review article mainly focuses on the novelty of using machine and deep learning techniques, specifically artificial neural networks (ANNs), support vector machines (SVMs) and hybrid machine learning (HML) algorithms, for predicting different pipeline failures in the oil and gas industry. In contrast to existing noncomprehensive reviews on pipeline defects, this article explicitly addresses the application of ML techniques, parameters, and data reliability for this purpose. The article surveys research in this specific area, offering a coherent discussion and identifying the motivations and challenges associated with using ML for predicting different types of defects in pipelines. This review also includes a bibliometric analysis of the literature, highlighting common ML techniques, investigated failures, and experimental tests. It also provides in-depth details, summarized in tables, on different failure types, commonly used ML algorithms, and data resources, with critical discussions. Based on a comprehensive review aforementioned, it was found that ML approaches, specifically ANNs and SVMs, can accurately predict oil and gas pipeline failures compared to conventional methods. However, it is highly recommended to combine multiple ML algorithms to enhance accuracy and prediction time further. Comparing ML predictive models based on field, experimental, and simulation data for various pipeline failures can establish reliable and cost-effective monitoring systems for the entire pipeline network. This systematic review is expected to aid in understanding the existing research gaps and provide options for other researchers interested in predicting oil and gas pipeline failures.","Advanced neural networks; AI algorithms (machine learning); Energy transportation system (pipeline); Oil and gas","en","review","","","","","","","","","","","Pavement Engineering","","",""
"uuid:08ee6883-4804-4a3d-809d-7376fa6f41f0","http://resolver.tudelft.nl/uuid:08ee6883-4804-4a3d-809d-7376fa6f41f0","Diverse Explorations of Rainfall Nowcasting with TrajGRU: Mitigating Smoothness and Fading Out Challenges for Longer Lead Times","Zou, Yanghuan (TU Delft Civil Engineering & Geosciences)","Schleiss, M.A. (mentor); Fioranelli, F. (graduation committee); Taormina, R. (graduation committee); Delft University of Technology (degree granting institution)","2023","Machine learning models offer promising potential in precipitation nowcasting. However, a common issue faced by many of these models is the tendency to produce blurry precipitation nowcasts, which are unrealistic. Previous research on the deep learning model - TrajGRU (Shi et al., 2017) indicated that data imbalance in radar images and the double-penalty effect of pixel-wise loss functions are underlying causes for this blurriness.
In this thesis, we continue to explore various approaches to improve the predictive performance of TrajGRU. Our research has first investigated spatially and temporally enhanced loss functions to address the two remaining issues: data imbalance and double penalty. The second part of our research focuses on manifold optimizations within the model network, such as incorporating additional model inputs or increasing batch size, to understand the model’s limitations.
Our results reveal that enhanced loss functions did not lead to predictive improvements and even resulted in undesired checkerboard patterns. Changes to the model network make a difference in the image sharpness and predictive rain evolution. Our visual analysis indicates that a larger batch size generates sharper rain field edges; predictions by using multiple parameter groups exhibit more rain dynamics. The incorporation with other transformed datasets introduces finer structures within rain fields. Although the blurriness has not been completely resolved, our study recommended future work can continue exploring the optimization in the TrajGRU network.","Precipitation; Nowcasting; Deep learning; Weather Radar; Blurriness; GRU","en","master thesis","","","","","","","","","","","","Water Management","",""
"uuid:e201a387-3526-4d17-bad8-8faa6f3038a4","http://resolver.tudelft.nl/uuid:e201a387-3526-4d17-bad8-8faa6f3038a4","SymbioSys: A Low-tech, Three-dimensional, Circular, Façade Cladding System which Utilises Waste Materials and Fosters Local Urban Biodiversity","Nouws, Marilse (TU Delft Architecture and the Built Environment)","Ioannou, O. (mentor); Tillie, Nico (mentor); Jenkins, A.J. (mentor); Rocco, Roberto (graduation committee); Delft University of Technology (degree granting institution)","2023","The negative effects of global climate change are experienced more clearly every day, meaning that significant alterations across all causing sectors are necessary. However, the influence of the building industry as one of the most polluting sectors, is immense, but therefore this industry also has a high potential in mitigating the greenhouse gas emissions by applying circular design principles, such as circulating products and materials, and thereby designing a more sustainable, circular and healthy living environment. Additionally, increasing the amount of nature in the built environment will also contribute to this manner, nonetheless the ongoing trend of urbanisation causes a challenging dilemma between facilitating more residences and adding extra nature to the cities. Hence, new strategies of greening cities are essential to resolve this problem, at which utilising building envelopes as hosting surfaces for fostering vegetation and fauna form a highly potential solution.
Therefore, the main objective of this thesis is to design a low-tech, three-dimensional, circular façade cladding system which utilises waste materials and fosters local biodiversity in urban areas. To properly design and develop this cladding system, research has been conducted through literature and case study review in the fields of circular design and biodiversity implementation in the façade industry and by physical and digital design experimentation and modelling.
Whereas, the research phase resulted in various potential low-tech manufacturing techniques, suitable reclaimed materials, modular and Design-for-Disassembly design principles and a selection of building-reliant flora and fauna species to implement in the design of the system, collectively facilitating the guidelines for the design phase. Finally, after an extensive design process a three-dimensional façade system derived consisting of three main modular elements, constructed from merely five unique planar components. Through the principle of rotation, a total of nine variations of the modules are generated, which facilitates not only the implementation of local biodiversity, but also creates an intriguing architectural language.
From this thesis, various conclusions have been drawn, including that in order to optimise the circular value of the design, the decision has been made to select the majority of the waste materials based on their local availability whenever the system is implemented in a certain location and at a specific timeframe. Moreover, the low-tech design strategy contributes to the involvement of the system’s end-users, eventually accelerating the transitioning process and furthermore increasing people’s awareness, knowledge and interest regarding circular, sustainable and nature-inclusive design subjects.
Academic research has lacked a specific information system design to directly monitor emission reduction at the source to award carbon credits efficiently. This research proposes a solution that includes distributing clean cookstoves and creating a digital platform to facilitate carbon credit recording and distribution, along with an integrated payment mechanism. The information system architecture plays a pivotal role in scaling sustainable cooking projects and combating climate change.
To address the research question, ""What is a possible design for a digital multi-actor platform for the issuance of carbon credits?"" a hybrid approach integrating Peffers's design science research framework and a system engineering methodology is employed. The study comprehensively analyses the Rwandan context, identifying 15 functional and 22 non-functional requirements for the system. A functional and logical system architecture is then presented with detailed interfaces. The system architecture's evaluation includes verifying functions and logical system elements against requirements and validating the system through expert interviews.
This research fills a gap in the literature by offering a systematic design cycle for tailored information systems in clean cooking projects, aiding stakeholders in context analysis, requirements elicitation, and system architecture design. It introduces an architecture valuable to information systems researchers and practitioners, especially in sustainable finance projects. The design cycle is a practical guide through various development stages, facilitating comprehension of essential requirements. These findings benefit researchers delving into information system design for clean cooking and sustainable finance initiatives. Furthermore, the adaptable system design provides a valuable resource for the FairClimateFund and related initiatives, supporting the adoption of information systems and issue resolution in sustainable finance, furthering the sustainability agenda.","Carbon credit; Clean cooking; Information system; design science research","en","master thesis","","","","","","","","","","","","Complex Systems Engineering and Management (CoSEM)","",""
"uuid:da742090-800c-44c7-88fe-8dc5e1dee1c5","http://resolver.tudelft.nl/uuid:da742090-800c-44c7-88fe-8dc5e1dee1c5","Dynamic Simulation of Green Ammonia Synthesis Plant","Kambhampati, Sampreeth (TU Delft Mechanical, Maritime and Materials Engineering)","Goetheer, Earl (mentor); de Jong, W. (graduation committee); Ramdin, M. (graduation committee); van Zee, Gerard (mentor); Delft University of Technology (degree granting institution)","2023","The carbon emissions from human activities are causing significant harm to the planet, leading to increased temperatures, melting of polar ice caps, rising sea levels, and other negative impacts on the environment. One promising solution is the use of green hydrogen as a fuel source, which could have a much lower carbon footprint than traditional fossil fuels. The production of hydrogen can be achieved through various methods, including the electrolysis of water, which splits water molecules into hydrogen and oxygen. To mitigate these effects and ensure a sustainable future, countries are taking various measures to reduce their carbon footprint, including increasing the use of clean energy sources and improving energy efficiency. Hydrogen storage and transportation pose major challenges since it is the one of the lightest gases leading to low energy densities.
Ammonia is emerging as a hydrogen carrier due to its high gravimetric storage densities of hydrogen. It is produced through the combination of hydrogen and nitrogen using the Haber-Bosch process. Ammonia can then be used as a clean and efficient fuel for various applications, such as transportation and power generation. Fluctuations in the hydrogen feed flow rate, resulting from variations in renewable energy sources can significantly impact the pressure and operating temperature within the system.
}Morocco holds significant potential for renewable energy development due to its favorable geographic location and natural resources. The geographic location situated close to Europe makes Morocco well positioned for exporting green hydrogen to European markets. The chosen location for the ammonia plant is Boujdour in Morocco due to its excellent wind capacity factor of 67%.
Modern ammonia production plants employ control systems to maintain stable pressure. When there is a reduction in hydrogen feed flow rate, these reductions result in severe pressure reductions which would lead to metal fatigue and damage the entire production unit. Hence, these control systems respond by adjusting parameters to sustain pressure within the system. Aspen Plus Dynamics has been used in the present thesis work to model the dynamics of the ammonia synthesis plant. The varying hydrogen feed flow rate is a consequence of renewable energy fluctuations, which is served as the basis for modeling three distinct scenarios involving a 20%, 50%, and 70% reduction in hydrogen feed flow rate. Three distinct control strategies were developed where each control strategy, based on controlling the cooling duty of the condenser, manipulating the brake power of the recycle compressor, and regulating the nitrogen feed flow rate, demonstrated effective stabilization of the system's pressure, even during dynamically changing input conditions. Both linear and step reduction in hydrogen feed flow rate have been considered to gain understanding of the dynamic the behaviour of the system.
Significant outcomes were found when a reduction in hydrogen feed flow rate is imposed on all three control strategies. For a 20% reduction in hydrogen feed flow rate, the condenser's duty reduced from -1.2 MW to -1.05 MW, while the brake power of recycle compressor reduced from 12.5 kW to 5.5 kW. Furthermore, the stoichiometric ratio of H2:N2 changed from 3 to 2.8. These changes successfully stabilized the pressure in the ammonia synthesis plant under varying hydrogen input flow rate...
This thesis aims to investigate whether deep learning models are able to increase segmentation accuracy as well as localization accuracy in 2D ultrasound images, specifically focusing on introducing spatial attention and optical flow information into U-Net backbone. Spatial Mask Attention U-Net (SMA-UNet) and Optical Flow Attention U-Net (OFA-UNet) were therefore proposed. The hierarchical experiments were designed to evaluate the effects of training loss, mask width and optical flow methods, and then select an optimal configuration for the segmentation models. Furthermore, U-Net, Attention U-Net and two proposed models were validated on datasets collected from pork and beef phantoms, as well as patients. The evaluation results indicate that OFA-UNet has significant improvement in terms of segmentation metrics and geometrical errors compared to the U-Net baseline and the U-Net only considering the mask attention. Specifically, the model achieved Dice of 86.7%, IoU of 88.2%, Precision of 88.6%, tip error of 2.7 mm and angular error of 0.002 radians on the pork dataset. Furthermore, the OFA-UNet shows robustness and consistency in evaluation metrics across three different datasets, indicating its ability to adapt to varying complexities of US datasets.","Ultrasound; needle insertion; Deep Learning; spatial attention mechanism; temporal information","en","master thesis","","","","","","","","","","","","Mechanical Engineering | BioMechanical Design","","52.0126341,4.3555860"
"uuid:b41c0e77-53aa-49b5-b95d-08ad4a60383b","http://resolver.tudelft.nl/uuid:b41c0e77-53aa-49b5-b95d-08ad4a60383b","Digital design workflow using fabrication - aware configurators","Vimalanathan, Kaviarasu (TU Delft Civil Engineering & Geosciences; White Lioness Technologies)","Schipper, H.R. (mentor); Janssen, Patrick (mentor); Coenders, Jeroen (graduation committee); van Nederveen, G.A. (graduation committee); Delft University of Technology (degree granting institution)","2023","The construction industry has undergone a profound transformation in recent years, driven mainly by integrating advanced digital tools. One such tool is configurators, advanced digital platforms that enable the integration of diverse knowledge domains, allowing architects, designers, fabricators, contractors, and engineers to explore many design variations and assess them against various parameters such as sustainability, cost, and manufacturability. However, Building Information Modelling (BIM) stands out as a game-changer, revolutionising how stakeholders collaborate and execute projects. Generally, a building configurator is made for product-specific criteria involving only one stakeholder. As to developing a multi-party configurator, this research delves into the transformative role of configurators in streamlining design workflows and enhancing collaboration among stakeholders in the construction sector.
The Design-Bid-Build (DBB) system, a predominant project delivery method in construction, operates under a linear workflow where the design and construction phases are distinct and sequential. During the bidding phase of this system, once the design is finalized and approved, it is put out to bid, inviting contractors to submit their proposals. To formulate their bid, contractors review the design documents and calculate the overall cost, considering labour, materials, overhead, and profit. This phase is characterized by competitive bidding, where multiple contractors vie to offer the most cost-effective solution to secure the project. This method allows owners to select a contractor that best aligns with the project’s budgetary and quality requirements.
In a conventional design workflow, the conceptual design undergoes numerous iterations of design and detailing before advancing to the fabrication phase. This iterative cycle, albeit integral to building planning, is notably time-intensive. Given this context, integrating manufacturing insights early in the design phases has been contemplated to expedite the overall design workflow.
Given the considerations above, the project’s proposal was focused on creating a prototype tool capable of executing the competitive bidding process involving contractors and subcontractors. It also translates the manufacturer’s expertise into a digital model. The example of the curtain wall system as a prototype was chosen and modelled as a solution to the proposed workflow. As an assumption, Two curtain wall systems, stick and unitised, are built by two fabricators. This proof of concept would enable the design of a curtain wall façade to be ready for the schematic phase after the bidding.
The foundational knowledge and information for developing this tool were sourced from the literature survey. The tool entered the modelling phase after the initial study of design workflow and façade elements. The configurator aimed to highlight the tool's user and developer and their impact during the modelling. The initial step involved setting the input parameters, using the knowledge from the manufacturer needed for the bidding, enabling the designer to create a model that aligns with the manufacturer’s capabilities. Two bidding fabrication-aware configurators were formulated based on the tool's back end.
Following the development of the two configurators, the project advances to the validation phase, structured into two distinct processes. Initially, the process was tested for its feasibility and workability of the configurator by various iterations of the input parameters. The outcomes of this process ensure the critical support requirements for the proof of concept.
Subsequently, the emphasis shifts to the professional validation of the configurator, a crucial step in the practicality of the solution. Four key validations were analysed in this step with professional feedback from the demonstration. The derived results offer insights into various aspects of the design’s effectiveness, productivity, functionality and market viability, providing pivotal information that can significantly influence the refinement and finalization of the project. The validation results are instrumental in making informed adjustments and optimizations, ensuring the proposed design workflow meets the intended objectives and specifications.
Adopting configurators in the construction industry is instrumental in addressing the challenges of increasing design complexities and the demand for sustainable, high-performance buildings. By providing a platform for real-time feedback and multidisciplinary collaboration, configurators allow for informed decision-making, optimizing designs for human comfort, environmental impact, and structural integrity. The exploration of configurators in this paper underscores their significance in advancing digital design workflows and highlights their potential in shaping the future of construction, marked by innovation, sustainability, and enhanced interoperability.
This report introduces a novel strategy aimed at bridging the gap between municipal sustainability goals and the interests of rooftop stakeholders. The strategy leverages pattern language principles, providing a flexible framework for tailoring rooftop solutions to diverse scenarios. It not only assists stakeholders in conceptualizing rooftop designs but also aligns them with their values. To illustrate the strategy’s effectiveness, it is applied to a neighbourhood case study, wherein various rooftop types are designed in alignment with the proposed principles.","Rooftop; Pattern Language; Urban Physics; Rotterdam","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Urbanism","",""
"uuid:743a370a-ba66-40c9-a88c-cbbe34baf9fc","http://resolver.tudelft.nl/uuid:743a370a-ba66-40c9-a88c-cbbe34baf9fc","The effect of microstructure design on the oxidation and reduction behaviour of iron electrodes: Improving the performance of iron-air batteries","Kamp, Harry (TU Delft Mechanical, Maritime and Materials Engineering)","Gonzalez Garcia, Y. (mentor); Yilmaz, A. (mentor); Santofimia, Maria Jesus (graduation committee); Delft University of Technology (degree granting institution)","2023","Pursuing sustainable and efficient energy storage technologies has led to advancements in iron-air batteries. Understanding the intricate relationship between the microstructural features of iron electrodes and their oxidation and reduction behaviour is crucial for optimizing battery performance and lifespan. This thesis aims to investigate the impact of microstructural characteristics, such as phases, grain size, and defect density, on the formation of stable iron oxide/hydroxide compounds and the evolution of hydrogen gas (HER), using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments in 6M KOH. The influence of an electrolyte additive, sodium stannate trihydrate, and an iron foam functioning as alternative electrode material are also examined.
Hot-rolled, pure iron samples were subjected to annealing heat treatments, resulting in different grain-sized specimens. A dual-phase steel, DP1000 steel composed of ferrite and martensite phases as well as hot-rolled and cold-rolled iron electrodes, completed the materials that formed this study’s basis. Initial surface identification via optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), atomic force microscopy (AFM) and X-ray diffraction (XRD) have been performed.
Results indicate a relatively lower formation of FeOOH for a DP1000 steel anode compared to cold-rolled alpha iron over 12 cycles. A marginally larger decline in HER kinetics is observed for a hot-rolled small grained anode compared to a coarse grained anode, while a clear effect of grain size on the development of Fe3O4 and FeOOH could not be established. An iron foam electrode showcases greatly enhanced anodic and cathodic current densities in comparison to solid sheet iron electrodes, due to its cellular structure. The effect of 0.01M sodium stannate added to the electrolyte illustrates a significant reduction in HER intensity for both foam and solid iron samples.
Detections were done on two homogenous isotropic turbulence (HIT) direct numerical simulation (DNS) datasets with Taylor Reynolds numbers of 175 and 1131, respectively. For both cases, the detected structures contained most of the volume and kinetic energy in the domain and were of the integral length scale. However, for the high Reynolds number, there were relatively half as many structures and the structures were roughly 4 times larger compared to those found in the low Reynolds number case.","large-scale structure; U-net; integral length; Reynolds scaling; PCA","en","master thesis","","","","","","","","","","","","Aerospace Engineering","",""
"uuid:7fac9792-7c0b-4d2c-af91-db35ec93dc8f","http://resolver.tudelft.nl/uuid:7fac9792-7c0b-4d2c-af91-db35ec93dc8f","Co-creating narratives about migration: A strategy to connect migration research and native citizens in the context of the paces project","empirio, ariele (TU Delft Industrial Design Engineering)","Mulder, I. (mentor); Brouwer, Willemijn (graduation committee); Vezzoli, Simona (graduation committee); Delft University of Technology (degree granting institution)","2023","In recent years, the EU and its member states have perceived migration as a significant challenge, leading policymakers to adopt prediction and control strategies that fail to consider the nature of migratory patterns (PACES Consortium, 2022). Research on migratory patterns in social science is extensive but not widely used in policy development, highlighting a significant gap between scholarly discussions and their impact on policymaking. PACES is a research project aiming to bridge the gap between social science research on migration patterns and policy development in the migration sector. In doing so, PACES aims to involve multiple participants in discussions about migration policies, as it appears that the lack of citizen involvement is a factor contributing to the inefficiency of migration policy. This project’s goal is to help PACES empower citizens and promote dialogues to create more informed opinions. The objective of this thesis is to facilitate a two-way information exchange between PACES and native citizens. PACES provides scientific knowledge on migration and policies, while citizens contribute their perspectives. The aim is to foster evidence-based opinions among citizens to achieve greater engagement and participation in in the public debate. To approach this objective, an analysis of the context of the public debate on migration was initiated, and system mapping was used to better define the stakeholders and dynamics between them. This analysis highlighted the lack of a direct connection between the world of research and citizens, who struggle to form opinions based on evidence, as the knowledge they receive is often shaped by political and media narratives. To better understand this distance, a smaller group of citizens was selected, specifically Italian emerging adults, to explore their perception of the public debate and their experiences in staying informed. Subsequently, a group of experts in the field of migration was consulted to understand their perception of the role of research and expert knowledge in the debate. The empirical exploration revealed that both experts and Italian emerging adults agree on the need to shift the way migration is portrayed in the debate, but they also agreed on the presence of a gap between research and citizens. To bridge this gap and support Italian emerging adults in forming opinions on migration based on scientific knowledge, this thesis developed a workshop that PACES could use to “co-create narratives about migration” with Italian emerging adults. In this workshop, knowledge is shared by focusing on different perspectives on a chosen topic and assisting Italian emerging adults in developing their own point of view and reworking it into new narratives to share with their peers The results of the workshop include an increase in the participants’ awareness of migration patterns and information that can help PACES in further research development that takes into account the point of view of native citizens. These results become the basis for initiating dialogues about alternative migration policies with policymakers, representing the perspectives of citizens on migration matters developed from scientific knowledge. The workshop can be further developed in the future to reach a broader audience and increase participation in the discourse on migration policymaking. In conclusion, the value of this project lies in its representation of the public debate, providing a simplified yet complex representation of the debate while placing citizens at the center. It also offers a strategy that PACES can scale further to lay the groundwork for a more open discussion on migration policy based on expert knowledge and resilience to social changes.","Migration; Participatory City Making; Delft Design Labs; Participatory","en","master thesis","","","","","","","","","","","","Strategic Product Design","",""
"uuid:3ca75a9e-6c93-4955-9913-cee95acde0d8","http://resolver.tudelft.nl/uuid:3ca75a9e-6c93-4955-9913-cee95acde0d8","Constraint-Driven Deep Learning for N-k Security Constrained Optimal Power Flow","Giraud, Bastien (TU Delft Electrical Engineering, Mathematics and Computer Science)","Cremer, Jochen (mentor); Rajaei, A. (mentor); Fosso, Olav Bjarte (mentor); Delft University of Technology (degree granting institution); Norwegian University of Science and Technology (NTNU) (degree granting institution)","2023","The transition to green energy is reshaping the energy landscape, marked by increased integration of renewable energy sources, distributed resources, and the electrification of other energy sectors. These changes challenge grid security, particularly regarding the N-1 security criterion, a crucial factor in preventing blackouts. Furthermore, climate change is contributing to the growing frequency of extreme weather events, which constitute the second major cause of blackouts. As grid complexity keeps on increasing, the need for N-k security, where k lines fail simultaneously, and increased resilience against extreme weather events is becoming increasingly evident. This necessitates studying the security constrained optimal power flow (SCOPF) problem considering multiple line outages (N-k). Current methods exhibit poor scalability as k increases. In response to the challenge of limited scalability, this thesis proposes a constraint-driven machine learning approach to approximate N-k SCOPFs.
The proposed approach relies on the linearized direct current optimal power flow. The approach utilizes a neural network to map power system loads to generator setpoints. A feasibility restoration layer is employed to restore base case infeasible predictions. By incorporating line outage distribution factors (LODFs), all post-contingency flows are computed. The loss function utilized to train the neural network draws inspiration from the penalty function method. Lastly, a copula analysis computes joint outage probabilities for k \textgreater 1 enabling a probabilistic security assessment. The first academic contribution of this thesis is the development of a constraint-driven approach to approximate N-k SCOPFs considering all contingencies using LODFs. The second academic contribution is the formulation of a N-k risk based security criterion, providing an alternative to the current deterministic N-1 security criterion.
The approach shows promise in its ability to scale effectively to N-k contingencies. Using LODFs, the approach effectively computes all post-contingency flows for up to k = 3. Moreover, case studies show the constraint-driven approach's effectiveness in identifying violating post-contingency cases, with up to 173$\times$ speedups and close to optimal dispatch costs. However, the consideration of N-k contingencies holds combinatorial complexity, and more efficient methods need to be developed for the computation and storage of all LODFs, and for the computation of all post-contingency flows. Additionally, the proposed constraint-driven approach can not enforce any post-contingency constraints, necessitating post-contingency feasibility checks when security against specific contingencies is required. Next, by incorporating probabilities, the approach shows promise in improving power systems security and resilience, but further research is necessary.
In this thesis, only line outages are considered. In the future, the approach could be modified to additionally account for other equipment outages (e.g. generator outages). Furthermore, future research could investigate the adoption of this approach in corrective control settings, where it is employed in the restorative phase of a contingency event. Another suggestion is centered around the incorporation of graph neural networks in the proposed approach, which could provide a more scalable alternative to fully connected linear neural networks. Furthermore, more scalable methodologies could be explored to construct the matrix containing all LODFs, and a more scalable methodology for computing all post-contingency flows could be developed. Finally, future work could investigate how to utilize the proposed approach under varying conditions like network topology changes or changing outage probabilities.","Constraint-Driven Deep Learning; Security Constrained Optimal Power Flow; Line Outage Distribution Factor","en","master thesis","","","","","","Double degree in Electrical Engineering and Wind Engineering.","","","","","","European Wind Energy Masters (EWEM)","",""
"uuid:824312ee-1fba-449d-aa8b-029bdf886f1d","http://resolver.tudelft.nl/uuid:824312ee-1fba-449d-aa8b-029bdf886f1d","Visualization to Enhance Communication in Online Psychological Counselling","Zhang, Qixiu (TU Delft Industrial Design Engineering)","van Middelkoop, C. (mentor); Havranek, M.C. (graduation committee); Delft University of Technology (degree granting institution)","2023","How to enhance communication between people is always an interesting topic in the design area. After going through the research, the author set the specific context for online counselling due to the increasing demand for online counselling during the COVID-19 pandemic. The online format limits a lot of non-verbal information like body language, vocal tones, facial expressions, and posture (Keynan et al.) that is only available in face-to-face communication. This limitation is critical as counselling clients have broad expectations for assistance in various life aspects (emotional, social, vocational, educational, and physical) (American Psychological Association, 2008) and the effectiveness of counselling hinges on the relationship and trust between the counsellor and the client, making effective communication especially vital in the online counselling environment. The current online counselling service providers were studied to understand how people access relevant services. After conducting interviews with clients and counsellors experienced in both online and in-person counselling, it became evident that there were notable differences in the counselling process phases: before, during, and after the session. The during-session and after-session phases were selected for focused attention since the during-session is vital for communication between the parties and the client requires a mental shift to effectively transition from this phase after the counselling. Following the creative sessions and initial testing, the design vision was established: enhancing interactivity and connection in online counselling by augmenting sensory perception between the client and the counsellor. A system for monitoring and generating content assisted by artificial intelligence was conceptualised. The system could monitor the client's emotion and convey it to the counsellor, use the generated content to improve review and reflect activity, and help them better foster interaction and connection between the involved parties. The envisioned system aims to: 1. Enhance the client's perception of self-emotions and counsellor's engagement 2. Deepen the counsellor's understanding of the client's emotions, reduce their workload and improve engagement 3. Provide effective session reflection for the client, a unique advantage of the online system. The feasibility and limitations were analysed in terms of the emotion recognition technology and ethical issues. This concept could be integrated with current online video platforms or online counselling service websites and the design of this work could provide valuable insights and opportunities to enhance the entire online counselling process and potentially extend its benefits to other online communication environments.","Communication Design; Experience Design; Counselling Experience; Visualization; Online Communication","en","master thesis","","","","","","","","","","","","Integrated Product Design","",""
"uuid:84aa9ea8-0ac7-4358-bbf3-3629fcfacd5d","http://resolver.tudelft.nl/uuid:84aa9ea8-0ac7-4358-bbf3-3629fcfacd5d","Dementia day care as a green addition to the city: An urban take on the farm-based day care concept supporting people with early stage dementia","Versteegen, Robin (TU Delft Architecture and the Built Environment; TU Delft Architecture)","Jürgenhake, Birgit (mentor); van Deudekom, A.B.J. (mentor); Oorschot, L.M. (mentor); Lubelli, B. (graduation committee); Delft University of Technology (degree granting institution)","2023","The growing number of dementia patients in the Netherlands has many consequences. Many people with early stage dementia live at home and are cared for by relatives. This creates a lot of pressure and stress for both the patient and the informal caregiver. A well-known and popular solution to this problem is farm-based day care, which is unfortunately not yet applied in the urban fabric, despite its many spatial and functional advantages. In order to integrate this succesful typology in the urban fabric, the following research question was answered: ‘Can the successful characteristics of farm-based day care be implemented in the green-blue landscape of Dutch cities in order to support the spatial and architectural needs of people with early-stage dementia?’. Literature research and fieldwork shows that eight qualities make farm-based day care succesfull for people with early stage dementia: stimulating connection with nature, creating purpose in life, offering meaningful activities, supporting social interaction, supporting physical activity, focussing on healthy nutrition and offering a domestic atmosphere and offering daily structure. Using results from fieldwork and case studies, the eight themes have been made generically applicable in the form of design guidelines, to which the themes 'clear wayfinding' and 'balance in sensory stimuli' have been added. In order to make these features applicable in the urban fabric, they must fit in the Urban Green-Blue grid of the city, therefore the themes 'biodiversity', 'quality of life' and food 'production', from the theory on 'Urban Green-Blue Grids' by Pötz (2016), must be respected or strengthened while designing an urban care building. Locational guidelines resulted from this. These architectural and locational design guidelines are used to create an urban version of a care farm in the urban green-blue grid of the Hague.","Dementia care; Designing for dementia; Farm-based care; Urban green-blue grids","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Dwelling","",""
"uuid:4d413d2f-cb39-4ba6-be76-9d9a251f66c4","http://resolver.tudelft.nl/uuid:4d413d2f-cb39-4ba6-be76-9d9a251f66c4","Optimal Planning of Heavy Duty Electric Vehicles En-route Charging Network","Rong, Tom (TU Delft Civil Engineering & Geosciences)","Correia, Gonçalo (mentor); Krishnakumari, P.K. (mentor); Xu, Y. (mentor); Luo, D. (mentor); Delft University of Technology (degree granting institution)","2023","","","en","master thesis","","","","","","","","","","","","Civil Engineering | Transport and Planning","",""
"uuid:628f9a65-d4ec-46c9-8749-8b109bc944b7","http://resolver.tudelft.nl/uuid:628f9a65-d4ec-46c9-8749-8b109bc944b7","Augmented Reality Interfaces in Robotic Manipulation: Assessing the effects of autonomy levels and environmental complexity","Bessels, Koen (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Cognitive Robotics; Alliander)","Eisma, Y.B. (mentor); de Winter, J.C.F. (graduation committee); Nies, Luc (graduation committee); Delft University of Technology (degree granting institution)","2023","This study investigated the human-robot interaction of three different augmented reality interfaces that enabled an operator to control a robot arm. The first control methods gives the operator complete manual control by moving a holographic object which the robot arm copies (Direct control). The second control method allows the operator to manually set holographic waypoints which the robot arm autonomously tries to execute (Waypoint control). And the third control method, gives the operator the capability to specify a target location which the robot autonomously moves towards (Command control). An experiment was designed to give 30 participants the capability to control a Franka Emika Research 3 robot arm with a Hololens. During the experiment, the participant had to use each control method to move the end-effector of the robot arm from a starting position to a goal position in 9 different environments. The 9 environments were divided into three manually created complexity levels (Easy, Medium, and Hard), which were based upon the performance of an informed RRT* path planner that was simulated in 67.500 unique environments. The experiment results showed that Command control outperformed the other two methods in the success rate, path length, and operation time. In terms of number of routes Command control had in general a lower number compared to Direct control, showcasing that Direct control has more flexibility in route selection. Furthermore, Direct control required more skill to get a similar performances in path length, operation time, and number of collisions as Command control. The design of Waypoint control made this method too unpredictable for the participants to use proficiently, which was underscored by the very low success rate, the long operation time, and large path length of this method. Comparing the performance of the control methods against the complexity levels did not show many significant differences, except for the success rate that decreased with a more complex environment. In summary, each control method will require unique features to completely unlock the possibilities of an augmented reality interface. The three control methods show different performances, each with their own strengths and weaknesses. And the choice of a control method is therefore dependent on the task at hand.","Robot Control; Augmented Reality; robot manipulator; human robot interaction","en","master thesis","","","","","","","","","","","","Mechanical Engineering","",""
"uuid:3e3e721d-4bbe-41dd-845f-a9d582290e50","http://resolver.tudelft.nl/uuid:3e3e721d-4bbe-41dd-845f-a9d582290e50","Integrated Torque Vectoring and Path Following using Nonlinear Model Predictive Control","Bani, Klait (TU Delft Mechanical, Maritime and Materials Engineering)","Shyrokau, B. (mentor); Delft University of Technology (degree granting institution)","2023","This thesis introduces a novel model predictive controller (MPC) that integrates both torque vectoring and path following into one controller. Due to a need to improve vehicle safety, systems are being developed in order to improve vehicle handling. One system that is able to improve the vehicle handling is torque vectoring (TV). With torque vectoring, the magnitude and the direction of torque can be controlled by either applying the motor or brake torques. Additionally, in order to eliminate human error as a cause of accident, automated drive (AD) vehicles are being developed. A key task for AD vehicles is to perform path following (PF), where the vehicle follows a predetermined reference path generated by path planning.
Beforehand, these tasks were performed by separate controllers, where one controller performed path following and the other controller focused on torque vectoring. The disadvantage of this method is that it leads to sub-optimal results as both controllers have opposing objectives. The TV controller is able to decrease the steering angle in order to improve the vehicle handling, whereas the PF controller could require a higher steering angle in order to follow the path. By integrating both tasks, the novel
controller is able to optimise the control output such that both objectives are achieved.
The use of model predictive control strategies with TV have been studied and its ability to deal with hard constraints, while decreasing the state errors and control input, makes it a suitable choice to use it for TV. When the MPC strategy is compared to more common control strategies it is clear that the MPC TV algorithm provides better results in terms of responsiveness, lateral acceleration and vehicle handling. Furthermore, due to its ability to integrate multiple applications and its ability to handle a greater level of complexity, a nonlinear model predictive control (NMPC) formulation will be used to perform both torque vectoring and path following.
In order to test the new MPC controller, benchmark controllers have been created for comparison. The benchmark controllers are two controllers that are able to perform torque vectoring by generating a corrective yaw moment to follow the yaw rate reference. The torques are then allocated based on the size and direction of the corrective yaw moment. Then, the NMPC controller that performs path following by using both the steering angle and torques as an input will be compared to a controller that is able to perform path following by using the steering angle as an input.
The controllers are compared by using the sine with dwell test and the double lane change manoeuvre. These manoeuvres are used to test the lateral performance, vehicle handling, responsiveness and tracking performance of the vehicles. Key performance indicators (KPI) are used in order to evaluate the results regarding tracking performance and the vehicle handling.
The results show that the NMPC controller has an increase in performance regarding both path following and vehicle handling. When compared to the benchmark torque vectoring controller, the vehicle handling is increased by 5% and the lateral performance is increased by 6 %. Additionally, compared to the path following controller, by adding torque vectoring, the NMPC controller has improved the path
following by 4 %, the vehicle handling has been improved by 5 % and the responsiveness has been improved by 11 %.","Torque Vectoring; Path Following; Nonlinear Model Predictive Control; Autonomous Vehicles","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Vehicle Engineering | Cognitive Robotics","",""
"uuid:d254440c-fe2f-43c6-94aa-f7390c1b8e00","http://resolver.tudelft.nl/uuid:d254440c-fe2f-43c6-94aa-f7390c1b8e00","Weaving Knowledges for a more Sustainable and Fair Circular Economy: A Framework for Respectful and Collaborative Indigenous Research in Australia","Vecoli, Laura (TU Delft Technology, Policy and Management)","Pesch, U. (mentor); Lieu, J. (graduation committee); Delft University of Technology (degree granting institution); Universiteit Leiden (degree granting institution)","2023","What started as a research on Australian Indigenous Knowledge Systems and the circular economy (CE), turned into a much more complex and personal journey of what it means to do respectful and collaborative research with Indigenous communities. In this thesis, I attempted to build an understanding of the very rich and complex tapestry of Australian Indigenous knowledges, to explore how they may inspire alternative designs for a CE. The main assumptions, principles, and limitations of the conventional model of the CE are explored, and an Indigenous-inspired circular economy model is proposed. Alongside this research aim, I also documented my own learning process as I grappled with the challenges of conducting Indigenist research, and confronted the essential question of how we can genuinely value and engage with Indigenous communities in the realm of academic research.","Indigenous knowledges; Circular economy (CE); Decolonial research; Aboriginal and Torres Strait Islander; Australia; Industrial ecology","en","master thesis","","","","","","","","","","","","Industrial Ecology","",""
"uuid:0e21cba1-a238-43b0-935e-ef70ec9b160d","http://resolver.tudelft.nl/uuid:0e21cba1-a238-43b0-935e-ef70ec9b160d","All in? Identifying and tackling private sector’s barriers to data sharing: A Perspective on geospatial data in the Netherlands","PAPADIMITRIOU, CHRYSANTHI (TU Delft Architecture and the Built Environment)","van Loenen, B. (mentor); Calzati, S. (graduation committee); Rafiee, A. (graduation committee); Delft University of Technology (degree granting institution)","2023","There is a drive to create an inclusive open data ecosystem, that includes public, private and academic open data [Loenen et al., 2021]. There is a lot of existing research in Open Government Data [Janssen et al., 2012; van Panhuis et al., 2014; Martin et al., 2013] and plethora of OGD in the Netherlands. Although the private sector produces a lot of data, those are not open, as they are not participating in data sharing. In order, to fill the existing data gap, that OGD create, the EU [Commission, 2018], specifically with the Open Data Directive, started to promote more openness in private sector data, especially geospatial data. So far this, it is only done for public undertakings, as a sector in between public and private Boone and van Loenen [2022]; van Veenstra and van den Broek [2013]. The private sector is not bounded by legislation to share their geospatial data.
This research aims to identify what are the challenges to arrive at an ecosystem with more open private sector data, through the identification of the barriers in the process, in relation to the level of openness they are and how to move forward. Five categories of barriers are identified, strategic, technical, legal, economic, cultural and a multi model with 4 levels of openness is used, to identify the current state of geospatial data sharing of 9 companies in the Netherlands. The results show that companies that are providers of data are mostly sharing internally, trying to share with external users, while companies that are intermediaries are mostly sharing with some external users but they are not sharing fully open data yet, and the companies as user of existing open data are difficult to identify. This research demonstrates the influence of the role of the company in data sharing and the level of dataset, project, department in the barriers that the private sector faces and prevent them from sharing geospatial data in the Netherlands.","barriers; private sector; data sharing; geospatial data; level of openness; open data ecosystem","en","master thesis","","","","","","","","","","","","Geomatics","","52.15845467511299, 5.493432431296309"
"uuid:e70dc8f6-91a4-4d8a-9610-dc18618d1f19","http://resolver.tudelft.nl/uuid:e70dc8f6-91a4-4d8a-9610-dc18618d1f19","Reuse of scrap wood: in a building product","Mantje, Meike (TU Delft Architecture and the Built Environment)","Bergsma, A.C. (mentor); Gommans, L.J.J.H.M. (graduation committee); Delft University of Technology (degree granting institution)","2023","Climate is changing. The average temperature on earth is rising due to excessive emissions of greenhouse gasses such as CO2. In the meantime the economy is a linear economy where a produced from exhaustive materials are consumed and turned into waste. In order to fight climate change and exhaust the earth less the greenhouse gas emissions need to decrease and less waste needs to be produced. The government has set goals to have a circular economy by 2050. A circular economy means the elimination of waste, instead all materials are reused and recycled to its final potential and new materials come from renewable sources.
One commonly used renewable material in the built in environment is wood. Besides, wood sequesters CO2, has a low environmental impact and can be reused and recycled. When more wood is used and forests keep growing, more CO2 is sequestered, especially when it is substituted for product that emit a lot of CO2. Wood can so contribute to the overall decrease in CO2 emissions.
But at the moment there is also a huge waste production of wood, with a annually production of 1,8 Mton waste wood, of which 435 kton is scrap wood (waste wood from the construction and demolition industry) (Sloopcheck, 2021). Most is incinerated or otherwise recycled. Only a small portion is reused. In order to contribute to the circular economy goals scrap wood should therefore be reused and recycled. This thesis aims to research why the portion of reusing scrap wood is so small and tries to find a suitable building product to show that scrap wood can and should be reused. The suitable building product is CLT, due to the used lamellae consisting of varying dimensions, mechanical properties and possibly wood species. This research shows that scrap wood can be implemented into scrap wood, although the portion of scrap wood into a panel depends on the availability of certain required properties. The substitution of scrap wood in CLT panels always results in extra CO2 savings, and therefore the reuse of scrap wood into CLT panels can contribute to reducing CO2 emissions.","scrap wood; reuse; sustainability; carbon emissions; CLT; Remanufacturing","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Building Technology | Sustainable Design","",""
"uuid:d9bf31c7-2ef2-40c5-ad5b-5747999b1f19","http://resolver.tudelft.nl/uuid:d9bf31c7-2ef2-40c5-ad5b-5747999b1f19","Is Aviation Technology going in the right direction regarding Climate Impact?","Grangier, Guillaume (TU Delft Aerospace Engineering)","Gangoli Rao, A. (mentor); Yin, F. (mentor); Delft University of Technology (degree granting institution)","2023","The aviation industry is shouting out its aim to reach ”net-zero carbon” by 2050. Nevertheless, air traffic is expected to grow up until then, and if fuel consumption is reduced by new technologies and aircraft, other sources of global
warming such as N Ox emissions and contrails are less considered. Therefore, the climate impact improvement of new technologies compared to older ones is not straightforward and requires a deep analysis. This work performs such an analysis via three steps: The selection of a new fleet to be compared with the actual fleet (2019), a comparison between the two fleets emissions via an Aviation Emission Inventory code, and a climate impact assessment with the tool AirClim. The new fleet analysed consists of the replacement of 14 old (entry in service before 2002) Airbus and Boeing aircraft with their new versions (entry in service between 2011 & 2018). The results show a reduction of 8.7% of fuel consumed by total aviation just by replacing the 14 old aircraft with the new ones. On the other hand, it leads to an 8.0% N Ox emissions increase. Nevertheless, the climate impact assessment concludes that this N Ox emissions increase lowers the surface temperature change due to aviation. This is explained by the strong influence of N Ox emissions location on its climate impact. Overall, this new fleet leads to a decrease in temperature change due to aviation in 2050 of 5.3 mK (-5.2%). This work gives important conclusions on the priorities that need to be set for the development of ’greener’ aviation technologies.
This pilot study aims to assess the environmental impact of Positron Emission Tomography/Computed Tomography (PET/CT) imaging, in the context of efforts to mitigate climate change. This is studied by investigating the energy usage, waste generation, and the radiopharmaceutical production.
Methods:
Power measurements of the PET/CT scanner were conducted over four weeks and during different power settings (system on, computers off, software shutdown and energy saving mode) with a power analyzer. Various outcome measures, such as energy and cost savings per hour, energy consumption per PET/CT radiopharmaceutical procedure, and total annual energy consumption in two distinct scenarios, were calculated. Additional power measurements of reporting stations and desktop computers were performed in off-mode, sleeping mode and active mode. The data for waste disposal was collected by counting and weighing consumables used for a Fluorine-18 Fluorodeoxyglucose ([18F]FDG) procedure. Waste streams were identified and the data categorized per waste stream. The workflow for producing the [18F]FDG radiopharmaceutical was mapped out and data on the energy consumption of the cyclotron and cleanrooms and waste generation was collected. All data was finally expressed in CO2-equivalents (CO2-eq) by using emission factors.
Results:
Of the four different PET/CT power settings, the energy saving mode showed the most significant energy reduction compared to system on, resulting in ∼30% energy savings and a 0.94 kg CO2-eq emission reduction per hour. Furthermore, the energy consumption of various radiopharmaceutical procedures showed results ranging from 3.03 (2.90-3.09) to 5.15 (5.00-5.41) kWh/procedure (1.90 to 1.12 kg CO2-eq). The reporting stations and desktop computers showed both a ∼71% energy reduction in shutdown mode compared to system on. Correct waste separation of plastics and paper showed a ∼64%
CO2-eq reduction per procedure. For radiopharmaceutical production, the impact of the cyclotron’s energy consumption was found the largest (0.44 kg CO2-eq/procedure) compared to HVAC energy consumption (0.13 kg CO2-eq/procedure) and waste disposal (0.003 kg CO2-eq/procedure).The total environmental impact of [18F]FDG PET/CT imaging was measured at 2.01 kg CO2-eq per procedure, with PET/CT scanner energy consumption (62%) and cyclotron energy consumption (22%) being the primary contributors.
Conclusion:
This study showed that the environmental impact of PET/CT imaging is substantial and that it can be reduced by implementing energy saving strategies during non-operational hours, improving waste segregation for recycling and optimizing the energy efficiency of cyclotrons and cleanrooms. Furthermore, hospitals and manufacturers can even reduce the impact further by addressing opportunities such as using eco-friendly or recycled materials and incorporating green energy sources for power supply. Future research should focus on increasing energy-efficiency of scanners, cyclotron and HVAC systems, reducing the scan length and reducing low-value scanning to further decrease the environmental impact of PET/CT imaging while maintaining high diagnostic standards.
To improve freight and traffic operations on freeways, this dissertation focuses on obtaining insights into the on-trip behavior of truck drivers and influencing this behavior for congestion relief. To this end, this dissertation develops new mathematical models and control methods for the strategical, tactical and operational behavior of truck drivers by analyzing emerging datasets and designing novel cooperative intelligent transportation system (C-ITS) applications.....","","en","doctoral thesis","","978-90-5584-337-4","","","","","","","","","Transport and Planning","","",""
"uuid:03d907d1-f44d-45e9-a1ea-5110ccff91f2","http://resolver.tudelft.nl/uuid:03d907d1-f44d-45e9-a1ea-5110ccff91f2","Heritage Beyond Singular Narratives: Embracing Diversity in Participatory Heritage Planning Empowered by Artificial Intelligence","Foroughi, M. (TU Delft Heritage & Architecture)","Pereira Roders, A. (promotor); Wang, T. (copromotor); Delft University of Technology (degree granting institution)","2023","This PhD thesis explores the evolving field of heritage planning, focusing on the cultural significance of heritage properties. It advocates for a value-based approach that recognizes the diverse perspectives of stakeholders, including experts, policymakers, and users. While participatory heritage aims to foster consensus-building, tensions may arise due to varying cultural significance conveyed by different stakeholder groups. Conventional research methods are time-consuming and costly, limiting their effectiveness in heritage planning. To address this gap, this research aims to utilize Artificial Intelligence (AI) models and information repositories, such as social media platforms, to understand the cultural significance of built heritage from different stakeholder groups’ perceptions.
This research presents a theoretical framework that examines the factors influencing consensus-building on heritage values and attributes. Based on this framework, a public participation methodology empowered by AI is developed and tested in the case study of windcatchers in Yazd, Iran. This study compares the perceptions of three stakeholder groups: experts, policymakers, and users. The findings reveal consensus on the value of windcatchers while highlighting differing interpretations of their significance.
The AI-empowered methodology proves effective in uncovering stakeholder groups' understanding of cultural significance. This framework can be replicated in other case studies, facilitating participatory heritage practices. The thesis contributes to knowledge in public participation, cultural significance, and AI in heritage planning, offering insights for practitioners and policymakers to promote inclusive heritage practices. It emphasizes the importance of stakeholders' contributions and advocates for a more diverse and inclusive approach to heritage planning.
When site and climate are known there are specific design strategies which can be implemented to reduce energy consumption. Passive strategies such as windcatchers, trombe walls, roof ponds, sunshading, sun spaces or solar chimneys are not climate dependent. Their properties, however, change depending on the climate type they inhabit. Design factors such as volume, fenestration characteristic and material choice have an impact on energy consumption and are design decisions taken in early design stages.
Energy simulations have the possibility to inform early in the design stage. This thesis focuses on an optimization workflow which generates and stores simulation data throughout each design step segregating: volume, fenestration, materials and passive strategy integration. The workflow is separated into two potential paths; multi-objective comparison, focusing on comparing design option with other self-defined design options and multi-objective optimization, centered around running genome optimizations through Grasshopper’s Wallacei, minimizing or maximizing fitness values.
The workflow aims at developing knowledge throughout the design process, balancing qualitative and quantitative data to generate a data-informed design. A multi-objective approach strengthens the decision making process and presents the trade-offs required to obtain the design improvement. Ultimately, design is a conscious decision. Expanding knowledge will serve to guide and inform but never to define a design. Reducing energy consumption is a design choice and comprehending the design alternatives will flourish possibilities towards a more energy conscious future.","climate responsive; Workflow; Optimization; passive strategies; climate morphing; grasshopper; human ui; User Interface","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Building Technology","",""
"uuid:d610bd52-b5dc-47ad-ae77-b4e73d7ef947","http://resolver.tudelft.nl/uuid:d610bd52-b5dc-47ad-ae77-b4e73d7ef947","Quantifying Cerebral Autoregulation in Children with Severe Traumatic Brain Injury","Robles, Tahisa (TU Delft Mechanical, Maritime and Materials Engineering)","Schouten, A.C. (mentor); Kuiper, Jan Willem (mentor); de Jonge, Rogier (mentor); van Twist, Eris (mentor); Delft University of Technology (degree granting institution); Erasmus Universiteit Rotterdam (degree granting institution); Universiteit Leiden (degree granting institution)","2023","","severe traumatic brain injury; Pediatric intensive care unit; neuromonitoring","en","master thesis","","","","","","","","","","","","Technical Medicine","TM30004; 35 ECTS",""
"uuid:f1719bce-74af-4108-aff3-76c5c81d3f70","http://resolver.tudelft.nl/uuid:f1719bce-74af-4108-aff3-76c5c81d3f70","Unveiling the Hybrid Work Paradigm: A Study on the Effect of Hybrid Working on Organisational Commitment of Employees and Work Environment Preferences Among Young Professionals of ORGANISATION X","van der Lingen, Annick (TU Delft Applied Sciences; TU Delft Architecture and the Built Environment)","Vande Putte, H.J.M. (mentor); Koolwijk, J.S.J. (graduation committee); Delft University of Technology (degree granting institution)","2023","This study aims to explore the impact of employee separation as a result of hybrid working on the organisational commitment of ORGANISATION X’s workforce. The findings of this research aim to offer valuable insights to ORGANISATION X's understanding on how the alternating remote and in-office work setup may influence the commitment levels of ORGANISATION X's employees.
The research methodology employed in the initial study of this thesis encompasses quantitative research, in addition to a comprehensive literature review. This quantitative research entails surveying the entire office-based workforce at ORGANISATION X. The results of the researches have yielded fascinating insights, offering a deeper understanding of the complex interplay between hybrid working elements and commitment to the organisation. The primary research findings demonstrate a nuanced relationship between hybrid work and organisational commitment, with only two of the nine potential relationships between hybrid work and organisational commitment found. Therefore, the 'sense of belonging' or the organisational commitment referred to in this research can be seen as being affected by hybrid work only to a small, insignificant extent.
Additionally, the study explored the influence of other variables, such as physical proximity, dependency, and socio-demographic factors, on shaping employees' commitment to the organisation. The study shows a positive relation between physical proximity, particularly arranged in-person meetings, and dependency on co-workers and organisational commitment. These are believed to influence the separation awareness among employees.
This research, conducted as part of a master's graduation project, targets enhancing the motivation of post-stroke survivors to partake in both clinical and at-home rehabilitation. This involves examining relevant external factors and designing interventions in collaboration with the survivors themselves.
The research is primarily centered around patients from Rijndam Medical Centre, known for its wide-ranging post-stroke rehabilitation cohort and its partnership with Erasmus MC.
Two main methodologies frame this study: the Design Thinking ""Double Diamond"" Process Model and the Co-Creation design method. The former offers a fluid approach encompassing four stages – discovery, definition, development, and delivery – which can transpire simultaneously. The latter emphasizes active participant involvement, granting firsthand insights and feedback. Based on the insights from Co-Creation, the research involved qualitative analysis, ideation, and culminated in the project's final design and evaluation.
Initially, identity was presumed to influence the psychological constructs impacting motivation. Field research affirmed the role of external factors in shaping identity and motivation. This led to the formulation of a table categorizing factors affecting motivation, serving as a foundation for further exploration on enhancing stroke survivors' motivation for rehabilitation.
However, due to limited participant involvement, the precise relationship between identity and motivation couldn't be firmly established. Current findings suggest that focusing on stroke survivors' overall well-being and social connections may be more beneficial than solely emphasizing identity within intervention tools.
Given the research's six-month duration, future in-depth studies are recommended for those keen on this topic. It holds promise for refining post-stroke intervention strategies.
We found that decentralized repositioning strategies have better performance in reducing waiting time, while the centralized strategy is better at increasing driver income and service rate. We also found that when platform information is accessible, the system has the best performance when 20% to 60% proportion of drivers utilize platform information when making decisions.","Ride-sourcing; Repositioning; Agent Based Model; Transport Network Companies","en","master thesis","","","","","","","","","","","","Civil Engineering | Transport and Planning","",""
"uuid:e421a6c0-e7ac-4f0b-9a21-7ea888eb237e","http://resolver.tudelft.nl/uuid:e421a6c0-e7ac-4f0b-9a21-7ea888eb237e","Preservation through Adaptation: Revitalising St Barbara church with a focus on preservation and choice of materials","Bon, Adriaan (TU Delft Architecture and the Built Environment)","Visser, C. (mentor); Smit, M.J. (graduation committee); Quist, W.J. (graduation committee); Romein, A. (graduation committee); Delft University of Technology (degree granting institution)","2023","The upcoming circular economy has consequences for the application of materials within the building sector, which requires a different mindset and way of designing from the architect. The aim of this research is to develop a Circularity Overview in which the materials of a building can be assessed for circularity and environmental impact. The Overview can thus be used as a tool to test materials of an existing building, materials for a design, or can be used as a tool during the design process for adaptive reuse. This allows for orderly weighing of options and making choices, therefore it is a tool that can be of interest to students and architects who will be working with circular material use. The Overview is developed from criteria that have been compiled through desk research, for which it was important that the criteria are measurable and verifiable so that results can be replicated and traced. Knowledge about circularity was generated through literature research, after which six case studies were analyzed with an objective view. By testing the Overview on both newly built circular projects and transformed buildings, it emerged that the combination of material use and construction technique of both, such as reusing materials, applying detachable connections, and keeping existing structures intact as much as possible, can lead to favorable outcomes in terms of circularity. The circularity of the case studies as well as the operation of the Overview itself have also become insightful as a result. Although the Circularity Overview has shortcomings due to the incomplete availability of data, it provides an indication of circularity in material use that can be used to support choices before, during, and after a design phase.
The Circularity Overview was used during the design process for the revitalization of the St Barbara church in Culemborg, which resulted in a design with minimal impact on the environment.","Circularity; Building Materials; Heritage re-design; Revitalization","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Heritage & Architecture","St Barbarakerk, Culemborg","51.9568778,5.2266061"
"uuid:603e2a25-d3ca-4177-9d1a-d46e6edcbb65","http://resolver.tudelft.nl/uuid:603e2a25-d3ca-4177-9d1a-d46e6edcbb65","The Adjustable Electric Bus: A Study to the Concept and its Social-Economical Performance","Qin, Mark (TU Delft Civil Engineering & Geosciences; TU Delft Delft University of Technology)","van Oort, N. (mentor); van Binsbergen, A.J. (graduation committee); Annema, J.A. (graduation committee); Delft University of Technology (degree granting institution)","2023","This research proposes a new concept of electric bus with adjustable interior modules. By installing different modules, it can adjust both its internal layout and battery capacity spontaneously to make itself resemble an electric city bus or an electric regional bus when it is needed. It makes use of difference between peak times of regional lines and city lines so that it provides the same service as one city bus and one regional bus can do. This research firstly verified the timetable feasibility of this adjustable electric bus. It turns out that one vehicle is able to operate both city and regional bus network with observable resilience, reduction of minimum vehicle number and saving of electricity consumption. However adjustable BEB is limited by its high purchasing and operation cost, making it not highly profitable in a whole concession period. Accordingly, this research suggests low-entry utility electric bus is the more reliable and cost-efficient choice to carry out combined network operation.","electric bus; adjustable; interior; timetabling; cost-benefit analysis; modular","en","master thesis","","","","","","","","","","","","Transport, Infrastructure and Logistics","",""
"uuid:7379667a-67d2-4287-bbda-4536630257c5","http://resolver.tudelft.nl/uuid:7379667a-67d2-4287-bbda-4536630257c5","Project Journey Embassy: Foster the continuity of multidisciplinary collaboration in an IT consulting service towards problem-solving innovation","Liu, Tongshu (TU Delft Industrial Design Engineering; TU Delft Design, Organisation and Strategy)","Calabretta, G. (mentor); Heijne, K.G. (mentor); Iliohan, Jimmy (graduation committee); Stoops, Maaike (graduation committee); Delft University of Technology (degree granting institution)","2023","The application of multidisciplinary collaboration has become a trend to prevent knowledge isolation obstructing business development (Schaubroeck, Tarczewski, & Theunissen, 2016), particularly in the IT industry as it pursue problem-solving innovation.
An IT service company is currently striving to transform into an IT innovation consultancy. Despite having a full-functional workforce and the Project Journey model, it is challenging for them to sell and conduct problem-solving projects to their clients. Not every employee from various disciplines is ready for multidisciplinary collaboration.
The project went through a variant Double Diamond process. The initial assignment was to mitigate the potential misunderstanding between different disciplines. After the generative design research to investigate the context and identify problems, the researcher concluded with a reframed problem as an essential need to have a continuous and concrete guideline for the company’s multidisciplinary way of working (WoW).
The conceptualization process commenced with two co-creation workshops involving frontline workers. Subsequently, the solution is refined based on the insights from previous research and feedback during the sessions. The researcher also drew inspiration from established literature, such as the classic RACI model for multidisciplinary project management and the organizational change management model Plan-Do-Check-Act (PDCA). The final solution comprises three components.
Firstly, as a multidisciplinary WoW framework, Project Journey Blueprint was outlined under seven factors in the service blueprint format. It is more concise, intuitive, and actionable than the classic RACI matrix, with an emphasis on value-based illustration. It reduces misunderstandings between different disciplines and fosters a more efficient and effective multidisciplinary collaboration.
Secondly, a co-creation toolkit called Project Journey Embassy was developed to facilitate the Project Journey guideline development with the aim of evoking ownership and mutual understanding. It includes a generative workshop within each discipline and an alignment workshop across all the disciplines, resulting in a consensus on the multidisciplinary WoW guideline. The guideline includes the ideal team configuration and a Minimum Viable Team (MVT) for future projects.
Last but not least, a three-stage implementation approach was introduced to bridge the guideline into practice. The process begins with the bottom-up co-creation, followed by a circular organizational-level PDCA, where the Project Journey Blueprint is executed and updated quarterly. The third stage employs project-level PDCA where insights will be reported to discipline ambassadors and discussed in organizational 'Check' moments. The ongoing cycle ensures a resilient continuity of the multidisciplinary WoW.
The three-fold solution provides a clear path to foster the transformation towards problem-solving innovation by enhancing multidisciplinary collaboration. It can apply to a broader scope, as there is a common structure and similar project flow across the entire IT industry.","multidisciplinary collaboration; problem solving; IT innovation; co-creation; way of working; value; team management; Organizational transformation","en","master thesis","","","","","","","","","","","","Strategic Product Design","",""
"uuid:699c5b21-0224-42a6-8458-6747f39a61c9","http://resolver.tudelft.nl/uuid:699c5b21-0224-42a6-8458-6747f39a61c9","Maritime trade and the closed off space: How can architecture shape the invisible world of the consumers industry into a future space where human coexist with this automated machine?: A scenography of a machine","van Dalen, Marilou (TU Delft Architecture and the Built Environment)","Rommens, O.R.G. (mentor); Geerts, F. (graduation committee); Koskamp, G. (graduation committee); Delft University of Technology (degree granting institution)","2023","br/>
The case studies show that the integration of bio-based material is even more difficult in modular construction. It shows that the adoption revolves around wood products due to their proven quality and reliable supply. While acknowledging the potential and benefits of bio-based materials, construction companies perceive material replacement not as the most cost-effective option, making the adoption of bio-based materials to the existing system a formidable task. Additionally, the study also underlines the insufficiency of bio-based materials' performance and capacity to fulfill larger-scale modular building production.
Strategic pathways for IC companies encompass supply chain integration to scale up production capacity and joint R&D to speed up product development. Together with the regulatory bodies, companies can increase engagement in bio-based construction to attract more players and develop clear regulations to mitigate the potential misuse of IC applications.","Bio-based building materials; Modular construction","en","master thesis","","","","","","","","","","","","Civil Engineering | Construction Management and Engineering","",""
"uuid:6c026ece-e2f4-4559-bd67-9f2741d4e05f","http://resolver.tudelft.nl/uuid:6c026ece-e2f4-4559-bd67-9f2741d4e05f","Railway Maintenance Scheduling: Improving the trade-off between runtime and solution quality for annual maintenance possession scheduling with a new, complex problem definition for the Dutch railways","Schmahl, Katja (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Algorithmics)","Yorke-Smith, N. (mentor); Oudshoorn, Menno (mentor); Baaijens, J.A. (graduation committee); Griffioen, H.J. (graduation committee); Delft University of Technology (degree granting institution)","2023","There is increasingly more expensive maintenance that needs to be performed on the Dutch railway network. Good maintenance schedules reduce costs, minimise hindrance to passenger and freight travel, and follow restrictions imposed by available resources, legislation and other agreements. The railway maintainer has modelled this maintenance scheduling problem, among others, on an annual level. This problem definition is very precise with different conflicting non-linear constraints and cost parts. The demands of the solving method depend on the phase of the scheduling process. In early phases, low runtime is most important, whereas best solution quality outweighs this runtime when the maintenance work is more finalised. In 2019, a simple greedy algorithm found good solutions fast, and a hybrid greedy-evolutionary algorithm was developed that resulted in the best schedules. However, since then, the problem definition has been made more realistic and thus complex. Therefore, this hybrid greedy-evolutionary algorithm is no longer feasible, and creating a maintenance schedule takes significantly longer than before. Research is necessary to better understand the impact of the more realistic model, and to once more have a good trade-off between solving time and solution quality available for the schedulers. In this thesis, we aim to achieve this by improving different aspects of the problem and solving methods. Most experiments were done with the maintenance schedule of 2024, and results were verified on the years of 2023 and 2025. First, general problem analysis and implementation improvements reduced the runtime from around twenty-four hours to three hours with the greedy algorithm. Then, approximations were applied in the passenger hinder to further reduce the runtime by around half with a negligible negative impact on the solution quality. Due to these speed-ups, it was possible to use more elaborate solving methods. New experimental results showed that the greedy algorithm still finds solutions fast. The hybrid greedy-evolutionary algorithm found better quality schedules, but required more runtime. Furthermore, a novel solving method with look-aheads was proposed, which showed some potential for cost reductions, but was dominated by the hybrid algorithm. Every algorithm uses the greedy heuristic as a subroutine. Results showed the importance of finding the right order for greedily scheduling the requests. A proposed new order function improved the quality of the resulting maintenance schedules even further. To conclude, the increase in complexity of the problem definition in recent years has made solving more difficult. To still find good solutions in a similar time, a better performing greedy heuristic was necessary. By applying different runtime optimisations to the objective evaluation and improving the solution quality of the greedy heuristic, a good trade-off between runtime and solution quality, using different solving methods, was realised for creating annual maintenance schedules for the Dutch railway network.","Planning & scheduling algorithms; Railway Maintenance; Maintenance Possession Scheduling; Railway network","en","master thesis","","","","","","","","","","","","Computer Science","",""
"uuid:0628e190-1219-4a10-8444-1c802ab26f79","http://resolver.tudelft.nl/uuid:0628e190-1219-4a10-8444-1c802ab26f79","The Inverted Estate: Reimagining inverse town planning to stimulate an improved human-nature connection, a case study for the Haagse Beemden","Beckker, Annelieke (TU Delft Architecture and the Built Environment; TU Delft Landscape Architecture)","van der Velde, J.R.T. (mentor); Overschie, M.G.F. (mentor); Delft University of Technology (degree granting institution)","2023","The Haagse Beemden in Breda is a neighbourhood that is designed towards the concept of the ‘’inverse town planning’’. In this concept, the underlying landscape structures the layout of the neighbourhood, resulting in an urban area with the landscape at its core. In the case of the Haagse Beemden this means that the neighbourhood was built around an old ‘’estate zone’’ and old green structures and waterways are still present in the design of the area, making the neighbourhood very green. The green character of the Haagse Beemden together with the used ‘’bloemkoolwijk’’ structure are focussed upon creating a neighbourhood with good social values and liveability. However, times have passed since the creation of the neighbourhood and nowadays its liveability and social values are under pressure. This thesis focuses on analysing what spatial aspects and characteristics could possibly cause these problems and how the green structure of the neighbourhood could be improved to stimulate a better nature connectedness, as nature connectedness can act as a catalyst for better social cohesion. The result is a design proposal for an ‘’estate park’’ that connects the neighbourhood to its core identity. This design is based on four created typologies (Central Green, Selective Collective, Connecting Green and Semi-Collective) that are funded by the findings in the theory and analysis phases.","inverse town planning; landscape architecture; urbanism; urban forestry; estate; nature connectedness; Haagse Beemden; Breda; bloemkoolwijk","en","master thesis","","","","","","","","","","","","Architecture, Urbanism and Building Sciences | Landscape Architecture","","51.611650, 4.733943"
"uuid:584d2e54-8b71-4a89-9ae7-91a8f6ab8634","http://resolver.tudelft.nl/uuid:584d2e54-8b71-4a89-9ae7-91a8f6ab8634","Investigating human altruism towards robots with a novel and reconfigurable interactive social robot","Ahmed, Akmal (TU Delft Industrial Design Engineering)","Boyle, J.H. (mentor); Rozendaal, M.C. (graduation committee); Murray-Rust, D.S. (graduation committee); Delft University of Technology (degree granting institution)","2023","As robots become increasingly popular and co-inhabit spaces with people, there is a need for designing robots that people are comfortable interacting with. For robots to successfully integrate into human society, it is important to design robots in a way that enhances the quality of the human-robot interaction. While the human-robot relationship typically exists to serve people, there will be instances when robots require human assistance. This project aims to investigate people’s interactions with robots that need their assistance. It employs a robot designed to test people’s willingness to help it achieve a goal under various scenarios.
The project in its entirety was quite an ambitious one given the limited scope of a graduation project. A literature review carried at the beginning helped identify key features a robot and an interaction should have, in order for it to be perceived positively by humans interacting with it. This review culminated in a list of design considerations which informed the design and the interaction. These design considerations were referred to throughout the project, while choosing ideas for the interaction and while detailing the chosen scenario. A state machine was used to explain the general behavioural states of the robot, and the electronic components that facilitated the desired interaction were chosen. These components were coded to reflect the desired behaviour of the robot during the interaction. Alongside this process, the robot was embodied as sub-assemblies incorporating these components. Once the robot was given a form, the components were designed to fit within a modular body that accounted for zoomorphic and anthropomorphic features, while retaining functionality of the components inside. During its embodiment, the robot was given the ability to express itself through displayed speech, sounds, facial expressions and body language. Additional structures like ""nests"" were also designed to support the robot's interaction. Once the interaction was designed and embodied, the robot was then plot tested, before being used as a research probe to conduct human-robot interaction (HRI) experiments to address the research questions outlined at the start of the project. Data was gathered through data logging via the robot, user observations and interviews. The results of the experiments indicate that people's willingness to help a robot is influenced by the narrative of a human-robot interaction, the effort level of the task required to help the robot, as well as individuals' attitudes towards robots. Increasing the effort level reduced people's willingness to help the robot, but only when the narrative of the interaction was simple and functional, demonstrating that a narrative which tries to engage emotionally with participants has a positive effect on their altruistic response. The experiments were also able to shed some light on the social dynamics that emerge when a robot co-inhabits a space with people, as more people informed others about the robot.
Before 2050 about 1500 kilometres of dikes and 500 sluices and pumping stations need reinforcements. Dike reinforcements could be executed by only adding soil to the dike. Another option is to add structural elements to the dike. A soil-based approach is preferred because there is more experience and a higher level of security of the reliability for a soil-based structure.
One such soil-based approach is a longitudinal mound. A longitudinal mound is a body of soil which is parallel with the dike, with the goal to reduce the wave height at the dike itself. As a result of the wave height reduction the necessary dike crest level will be reduced as well. Therefore, a reinforcement of the dike itself is not needed. The crest of this longitudinal mound is lower than the crest height of the dike. The longitudinal mound will be submerged during design conditions and will act like a submerged wave breaker.
Costs, emissions and construction time could potentially be reduced by using local soil. This local soil can be obtained in two different ways. Firstly, it is possible to use the surplus of soil of another local project for the longitudinal mound. Secondly, the soil for the longitudinal mound could be taken from the floodplain itself.
However, only little is known about the hydrodynamic effects of a longitudinal mound on the floodplain. This thesis research is done to find possible locations for a longitudinal mound, the hydrodynamic effects and the differences between a simple and more complex model of the longitudinal mound. This is done with a multicriteria analysis for the location study and with a conceptual model and a 2D D-Flow FM model for the hydrodynamic effects.
In the multicriteria analysis the studied criteria are the size of the floodplain, structures on the floodplain and inside the dike, the availability of clay on the floodplain, the habitats on the floodplain and the wave height at the dike.
The multicriteria analysis has been performed from the point of view from multiple stakeholders. For all locations a compromise is necessary. Different locations for a longitudinal mound are preferred depending of the point of view of the stakeholders.
In the conceptual model three design parameters for the longitudinal mound are taken into account, the crest height, the crest width and the slope. For each combination of these three parameters the conceptual model calculates the new equilibrium water level and the transmitted wave height from the longitudinal mound towards the dike. The transmitted wave height is calculated with the best empirical fit on multiple datasets by Friebel and Harris in 2003.
With the Van der Meer overtopping formula the freeboard of the dike above the water level can be determined. This is done for the original situation without longitudinal mound and subsequently for the situation with all combinations of the longitudinal mound. From these calculations it can be concluded that the necessary dike crest height decreases when a longitudinal mound is present. However, more soil is needed than for a traditional dike reinforcement.
Also the conceptual model does not include a backwater effect. The water level does not immediately jump to the new equilibrium water level, so the water level increase should be smaller than calculated in the conceptual model. On the other hand, in the conceptual model all waves are assumed to be perpendicular to the dike. If waves are not perpendicular the necessary freeboard is smaller. The absolute dike crest height reduction with a longitudinal mound is therefore smaller for non-perpendicular waves than for perpendicular waves.
The 2D D-Flow FM model has been supplied by Deltares. The grid consists of cells of 20 by 10 square metres on the main river channel and 20 by 20 square metres on the floodplain. To model the longitudinal mound with a higher accuracy the grid on the floodplain has been refined to 5 by 5 square metres. On this refined grid three different variants have been modelled. All variants have a crest height of about half a metre below design water level and their alignment is identical. For Variant 2 a connection of half the longitudinal mound height has been made with the dike. For Variant 3 the same volume of soil needed for the longitudinal mound has been removed from the floodplain by lowering it by 0.3 metres.
There are only small differences between the three variants. Compared to the original situation there was only a difference in the order of millimetres of water level at the main river channel. The main differences are found between the dike and the longitudinal mound. In this area the Bernoulli effect is found, at locations of increased flow velocity lower water levels are found and vice versa. The subsequent difference in water level is about 5 to 10 centimetres.
The flow velocity depends on the difference of flow area in longitudinal direction between the longitudinal mound and the dike, following the Bernoulli principle. So, the main contributor to the water level change on the floodplain is the alignment of the longitudinal mound. Therefore, the alignment of the longitudinal mound is an important design parameter and can be used to find a trade-off between increased water levels and increased flow velocity.
As this process is not incorporated in the current version of the conceptual model the results between the conceptual model and the 2D D-Flow FM model are different. Therefore, it is recommended that the water levels between the longitudinal mound and dike are calculated separately in the conceptual model. To do this the area between the dike and longitudinal mound can be split into multiple segments. With energy and momentum balances the water levels in these segments can be calculated.
It is also recommended that the 2D D-Flow FM model is used at a smaller floodplain as well to see if the effect on the main river channel is similarly small. Next, it could be helpful to try different alignments for the longitudinal mound to see how these influence the water levels and flow velocities.
Finally, in this research only the flow has been modelled in 2D. However, the wave reduction is also of importance. The next step is to add a wave model to the 2D model to as well. With this addition it would be possible to make the comparison between the wave height reduction in the conceptual model relative to a 2D model as well as for the water level.