Search Results

Measurement of low sediment concentrations in a pipe flow– A deep sea mining application

Master thesis (2025) - S.C.T. Laken, R.L.J. Helmons, A.M. Talmon, F.A. Doorn, Frans van Grunsven

Deep Sea Mining Polymetallic Nodules Sediment concentration measurement Coriolis Sensor

This thesis explores the measurement of low sediment concentrations in pipeline flows, a critical issue in deep-sea mining. The study aims to identify and validate a continuous measurement method capable of accurately detecting suspended sediment concentrations between 10-75 g/L. ...

This thesis explores the measurement of low sediment concentrations in pipeline flows, a critical issue in deep-sea mining. The study aims to identify and validate a continuous measurement method capable of accurately detecting suspended sediment concentrations between 10-75 g/L. These measurements are essential for minimizing the environmental impact of sediment plumes generated by mining operations.

The research begins with an analysis of material properties and flow dynamics, emphasizing the role of sediment particle size, and density in influencing suspension and settling behaviours. Highlighting the differences between concentration measurement and density measurement and the additional error involved. A review of flow regimes, turbulence, and their effects on sediment distribution within pipelines sets the foundation for understanding the complexities of representative sampling.

The thesis evaluates a range of measurement methodologies against criteria such as accuracy, range, spatial and temporal resolution, safety, cost, and impact on the flow. Optical, acoustic, conductivity, and radioactive source sensors were unsuitable due to limited range, low accuracy, or safety concerns. Promising alternatives include the U-loop, Coriolis, and vibrating fork sensors. The U-loop offers good accuracy and range, but causes significant pressure drops. Coriolis sensors provide excellent accuracy and broad range, but require careful sampling to ensure reliability. The vibrating fork sensor is simple and has a good range, but suffers from low accuracy and limited spatial resolution.

A key aspect of this research is the experimental setup, which integrates multiple sensor technologies in a controlled flow loop environment. Detailed methodologies for sensor calibration, installation, and data collection ensured the testing conditions. Tests are conducted under varying sediment concentrations, sediment types, grain sizes, and flow velocities to validate the accuracy and reliability of each measurement method.

The results reveal significant differences in sensor performance across test conditions. Test variables such as sediment type, concentration, and flow velocity are shown to influence sensor performance.

In conclusion, suspended sediment concentrations from 10 - 75g/L can be measured accurately using a Coriolis sensor. This sensor directly measures density which can be converted into concentration with minimal calibration or correction, demonstrating superior accuracy and precision across diverse flow conditions. Although it reliably detects finer deep-sea sediment, minor challenges remain when measuring coarser materials, such as nodule fines. Overall, the findings contribute to the development of environmentally responsible deep-sea mining practices, by facilitating real-time and accurate sediment monitoring.

SMURF: a Methodology for Energy Profiling Software Systems

Simulate and Measure to Understand Resource Footprints

Master thesis (2025) - O.K.N. Kaaij, Luís Cruz, J. Sallou, Arie Van Deursen, Anna Lukina, J. Silva

Understanding the energy profile of a complex, multi-faceted software system is difficult. In this thesis, we present a novel methodology, called SMURF, a five-step methodology that gives insights into the energy consumption of a complex system. The methodology is broadly applica ...

Exploring Genre Preferences and Audience Engagement in Multilingual Fanfiction

A Study of Popularity and Preferences

Bachelor thesis (2025) - J.Q.Q. Ye, E. Eisemann, Hayley Hung, C. Hao, I. Kondyurin

Sentiment Analysis Fanfiction Genres Topic Extraction

This study investigates how genre preferences and sentiment influence fanfiction popularity across multiple languages, focusing on English, Mandarin, Russian, and Spanish datasets. Leveraging advanced natural language processing techniques, including multilingual sentiment analys ...

Efficient Time-Integration Solvers for Shallow Water Equations on GPUs

A Case Study in Tidal Modeling

Master thesis (2025)

GPU computing Time integration Julia Shallow Water Equations Tides Pseudo-time stepping

The Shallow Water Equations (SWEs) for ocean applications can be discretized using finite differences, resulting in a system of time-dependent ordinary differential equations (ODEs). These ODEs can then be solved on a GPU using various time-integration schemes, which can be categ ...

Public Participation Powered by Design: Developing a Measuring Instrument to Enhance Citizen Science Engagement

Master thesis (2025)

Sensor Citizen Science Product Design Public Participation Environmental Monitoring Measuring Instrument

Citizen science, an approach where the general public collaborates with academic researchers to contribute to scientific research, offers significant benefits for both science and society. Despite its potential, the field faces significant challenges that limit its impact, partic ...

Citizen science, an approach where the general public collaborates with academic researchers to contribute to scientific research, offers significant benefits for both science and society. Despite its potential, the field faces significant challenges that limit its impact, particularly in maintaining participant motivation. Additionally, citizen science projects often struggle with issues related to cost, especially when they incorporate physical measuring instruments. Limited budgets typically result in instruments that lack robustness, usability, and scalability, further diminishing participant engagement, and in turn, the overall effectiveness of citizen science initiatives. These challenges formed the foundation of the project’s goal: design a measuring instrument for citizen science to enhance engagement.

Collaborating with design studio Dott Achilles, the project explored not only the technical and user-centred aspects of the design, but also the question whether commercialization could facilitate broader participation. The goal was to develop a product that could lower barriers to participation and increase incentives for both researchers and participants while adhering to the core principles of citizen science, such as transparency, ethical data use, and inclusivity.

To inform the design process, a comprehensive analysis of citizen science was conducted, combining a literature review with stakeholder interviews to identify key principles, challenges, and opportunities for improvement. This research led to the development of a vision for a modular, scalable and user-friendly product-service system that could engage a diverse range of participants across varying contexts, balancing the needs of citizen scientists, researchers, and local organizers.

Through an iterative process involving exploring, prototyping, testing, and refinement, a final product emerged centred around a physical measuring instrument. The instrument features customizable sensor modules and various mounting options, enabling deployment in numerous contexts, including outdoor residential and natural settings. Its plug-and-play design ensures accessibility for users, regardless of their technical expertise. The design adopts a stylized, friendly, and approachable aesthetic that aligns with citizen science principles and increases adaptability. Additionally, the design incorporates elements to inform non-participating, ambient users, stimulating trust and transparency. The robust, scalable, and repairable design allows the instrument to be reused across multiple projects, reducing environmental impact and enabling new financial models.

An integrated online platform complements the physical instrument. Features such as real-time data visualization, personalized feedback, and tools for data exploration and comparison were explored at a functional level, aiming to enhance participants’ motivation by acknowledging the critical role of their contributions. Particular attention was given to the interactive installation help that utilizes the instrument’s design cues to guide users during installation. This feature, alongside the instrument’s general usability, was validated through a usability study and expert reviews.

This thesis demonstrates how design can address the challenges of citizen science, particularly in relation to physical measuring instruments. By creating an impactful product that empowers citizens, enhances engagement, and supports local organizers, the project contributes to maximizing the scientific and societal impact of citizen science.

The impact of emotional journeys on fanfiction popularity

A computational analysis of linear correlations between emotional behavior and popularity

Bachelor thesis (2025)

Natural Language Processing Fanfiction Emotional arcs

Fanfiction writers always look for ways to make their stories more engaging. Analyzing what influences the popularity of fanfiction provides insights into readers' preferences and allows writers to tailor to these. This paper attempts to find linear correlations between fanfictio ...

What if fan-fiction, but also coding

How does fan-fiction differ in style to its original canon and does it affect its success?

Bachelor thesis (2025)

Natural Language Processing Stylometry Fanfiction

Natural language processing, specifically style, is not explored significantly in the context of fan-fiction. By using function word frequency analysis, this paper explores the similarity in style between original works and fan-fictions derived from them as well as the impact of ...

Designing circular strategies for the next-generation of insufflation

Master thesis (2025) - J.K. Schilperoord, Magdalena K. Chmarra, J.C. Diehl

Healthcare Sustainability Circular design Strategic design

The healthcare sector, while dedicated to promoting human well-being, is also a major contributor to declining environmental conditions, paradoxically adversely affecting health through resource-intensive and waste-generating practices. Laparoscopic surgeries using single-use ins ...

The healthcare sector, while dedicated to promoting human well-being, is also a major contributor to declining environmental conditions, paradoxically adversely affecting health through resource-intensive and waste-generating practices. Laparoscopic surgeries using single-use insufflation devices, or disposables, exemplify the tension between healthcare delivery and sustainability. This graduation project addresses these challenges by exploring and proposing circular strategies to mitigate the environmental impacts of disposables inside a insufflation system through strategic design.

The research follows the Double Diamond Design Framework, beginning with an in-depth context analysis of the environmental impacts of an average laparoscopic patient journey and an extensive literature review on circular economy principles. Empirical studies, incorporating semi-structured interviews with relevant stakeholders, provide insight from the hospital perspective. Intermediate findings are combined into a design scope, guiding subsequent work. Environmental hotspots are identified by combining a self-executed fast-track life cycle analysis with insights from existing studies. Finally, conceptual circular interventions are developed to address identified hotspots and improve the environmental sustainability of the insufflation system.

This results in a strategic sustainability plan designed to help the client, a medical start-up, integrate sustainability and create a truly “future-proof” insufflation system. This plan includes company level strategies offering recommendations for actionable steps, commitments, and documentation, potentially leading to a competitive advantage in hospital procurement processes and product level circular strategies. These include redesigning devices to reduce material use, introducing reusable or hybrid devices, and exploring recycling opportunities. Applying strategic design thinking, the proposed strategies balance sustainability ambitions and both the complexity and practical constraints of healthcare systems and medical start-ups, offering a roadmap for implementing more circular and sustainable medical practices.

In conclusion, this project demonstrates the potential for applying circular strategies to complex healthcare settings. By integrating circular economy principles, it exemplifies how sustainable healthcare practices can reduce CO₂ emissions and waste from single-use devices. Ultimately, this thesis underscores the growing need for healthcare to adopt circularity, enabling it to continue improving human well-being while respecting the planet.

Women in Transit

Considerations for Kitchen Design for Formal Settlements in Bangladesh

Master thesis (2025) - N.M. Keulen, A.G.C. van Boeijen, J. C. Diehl

Design Transition Bangladesh Women Cooking Social-cultural perspective Formal and informal settlements Preparing food

This project, Women in Transit: Considerations for Kitchen Design for Formal Settlements in Bangladesh, explores the challenges and key factors in designing kitchens for women in informal settlements. The focus is on women who have migrated from rural to urban areas, driven by ra ...

This project, Women in Transit: Considerations for Kitchen Design for Formal Settlements in Bangladesh, explores the challenges and key factors in designing kitchens for women in informal settlements. The focus is on women who have migrated from rural to urban areas, driven by rapid urbanization due to climate change and economic factors. As a result of this, informal settlements are increasing in Bangladesh.

The goal of this project is to enhance awareness among NGOs regarding key factors that need to be considered when designing homes for women who are currently residing in urban informal settlements. The central focus is food preparation and cooking, which play a vital role in the daily lives of these women.

Therefore, through interviews, field research, and a literature review, the report explores the cultural, social, economic, and practical aspects of kitchen design. It examines how women in rural areas often cook on open fires in private spaces, and how this changes when they move to urban areas, where kitchens are usually shared and gas stoves are used. The shift from rural to urban living brings both challenges and opportunities as women adapt to new cooking methods, environments, and social settings.

Furthermore, based on this research, design guidelines have been developed to help NGOs understand the needs of women transitioning from informal to formal housing more effectively. These guidelines focus on creating kitchens that support women’s social connections, maintain their cooking traditions, and address practical needs.

The final result of this project is a booklet that tells the story of Sadia, a woman who moves from a rural area to an urban informal settlement and eventually to formal housing. Sadia’s journey highlights the challenges women face in cooking, adjusting to new social dynamics, and adapting to new living conditions, as well as the opportunities that open up for her.

The aim of the booklet is to help NGOs thoroughly understand and empathize with women like Sadia when designing formal housing. The booklet provides design ideas for kitchens that are culturally appropriate and support women in their roles of cooking and caregiving. This is achieved by offering design options for both low- and high-density housing, as well as different living environments that can influence how women cook and manage their daily tasks.

Underwater anchorage design for combi-walls

Master thesis (2025) - M.A.J. van de Noort, M.Z. Voorendt, Hans Ramler, Gert Schotanus

Quay wall renovation Quay wall Quaywall Underwater anchorage Combi-wall Structure design

One of the challenges in modern ports is upgrading existing quay walls. Dutch contractor Hakkers BV has developed a device to install underwater grout anchors as a support for sheet pile walls. This technology was successfully tested during a pilot project in the Seinehaven for t ...

One of the challenges in modern ports is upgrading existing quay walls. Dutch contractor Hakkers BV has developed a device to install underwater grout anchors as a support for sheet pile walls. This technology was successfully tested during a pilot project in the Seinehaven for the Port of Rotterdam. Now they are curious whether underwater grout anchors can also be applied on combi-walls.

“The objective of this thesis is the design of an underwater anchoring system for combi-walls to enable the deepening of existing quays.”

For the design, the case study of the Afrikahaven was chosen. This project has a common type of combi-wall and therefore the design is applicable in many situations. There is currently no specific customer for the quay. The underwater anchoring system can be part of an upgrade proposal in case a customer is interested in deepening the bed level.

Because underwater grout anchoring of combi-walls was only a conceptual idea, this thesis carried out a full design process starting with the very basics. This was done by creating multiple concepts which varied the way of load transfer to the combi-wall. A multi criteria analysis resulted in the selection of two optimal concepts. These two concepts are designs where the anchors go through the sheet piles and are connected to a support structure that transfers the anchor forces to the king piles. These concept designs scored very well on the criteria for hole weakening and spatial usage. Hole weakening of the king piles was a major concern due to the capacity reduction at the locations of the largest moment distribution. By not placing the anchor through the king pile, its capacity does not need to be reduced. Additionally both concepts have limited protrusion outside the combi-wall system. This prevents conflicts with the mooring vessels.

For the two concepts various connection designs have been explored, including rubber connections, clamping connections, extendable connections, and conventional methods such as welding. After evaluating the pros and cons of each design, clamping connections emerged as the optimal solution.

A detailed design of the overall stability of the combi-wall was calculated using D-Sheet. The current situation is used as the starting point. Various positions and angles of the anchors where tested. Eventually the anchor was placed at -11m NAP at the location of the maximum moment distribution. It was essential to place the anchor at a relatively shallow angle to meet vertical stability requirements.

A critical part in the design was underwater anchor failure. An important finding is that the applicability of the current design standards used for anchor design is rather limited for underwater anchoring systems. Without considering the extent of redistribution, it is possible to create a structurally questionable design that still meets the common used standards. Therefore, it is important to thoroughly understand these standards and adapt their implementation if necessary for the design.

Evaluating the extent of force redistribution is crucial for determining anchor forces and stresses in the waling beam and king piles. To evaluate force redistribution, the design was modeled in SCIA
and calibrated using D-Sheet calculations focusing on deformations and anchor forces. The analysis revealed that force distribution depends heavily on the stiffness of the support structure. An overly flexible structure channels excessive force to upper anchors and increasing soil mobilization, while an overly stiff fixed structure risks a chain reaction of failures in adjecent anchors could occur. For the design, a CHF350x500 profile was chosen between the king piles with a moment-free connection. This allows for a redistribution of 40% of the forces to adjacent anchors. The remaining 60% of the anchor forces are absorbed by the four anchors at the top of the two king piles.

To ensure feasibility, understanding construction tolerances is crucial. The design accounted for king pile and sheet pile deformations, with a deformation allowance of 100 mm for the sheet pile. Minor deviations due to ovalization were also considered. While it is unrealistic to address all uncertainties in a single design, using a multi-beam survey to measure the quay wall with 1 mm accuracy is recommended. This approach cannot eliminate construction tolerances but helps mitigate unexpected conditions during installation by incorporating them in the design phase.

The clamping design is based on a support structure where the anchor will be supported in the waling beam. The waling beam will transfer the horizontal forces to the king piles. To avoid underwater welding, a semi-clamp has been designed. These clamps can be connected using four bolts, which can be tightened underwater easily because the system is not yet under tension. Only after pre-stressing the anchor, the clamps will be drawn tightly around the king pile. Vertical stability will be provided by steel cables, which will be attached to the capping beam where the vertical forces will be transfered to the king piles.

To ensure constructability, various components are adjustable. For instance, the waling beam can be cut to size above water and welded between two end plates. An extendable HDPE tube is incorporated into the waling beam to accommodate deformations of the sheet pile wall. Additionally, the radius of the clamps has been slightly enlarged to account for ovalization deformation. This design aims to minimize operations underwater and be construction tolerance proof.

The design makes it possible to deepen the existing combi-wall in the Afrikahaven by 1.5 meters. This enables an upgrade without requiring drastic changes to the quay. The proposed design is applicable to all similar combi-wall configurations. However, for each project, specific construction tolerances must be reassessed, and the redistribution of forces during anchor failure must also be evaluated.

What if fanfiction, but also coding: Investigating cultural differences in fanfiction writing and reviewing with machine learning methods

Fine Tuning a BERT-based Pre-Trained Language Model for Named Entity Extraction within the Domain of Fanfiction

Bachelor thesis (2025) - N.P.A. Kindt, Hayley Hung, C. Hao, I. Kondyurin, E. Eisemann

Natural Language Processing (NLP) Domain Adaptation BERT Fine-Tuning Named Entity Recognition Language Models Natural Language Understanding Fanfiction

The introduction of Pretrained Language Models (PLMs) has revolutionised the field of Natural Language Processing (NLP) and paved the way for many new, exciting large-scale studies for various areas of research. One such field presents itself in the emerging digital literary corp ...

Modeling Noise Propagation and Mitigation for Future Offshore Impact Pile Driving

Noise Predictions for Larger Monopiles and Hammers

Master thesis (2025) - A.F. Stroeve, Apostolos Tsouvalas, R.J. van Leijden, Y. Peng

COMSOL Multiphysics Numerical modeling Offshore energy Offshore wind Pile driving Bubble curtain Noise mitigation SILENCE Underwater acoustic modeling Pulse prolongation

Impact pile driving is the predominant foundation technique for offshore wind turbines. The pressure waves generated during pile driving produce high noise levels that can harm marine life. To protect marine mammals, regulations have been established to limit underwater noise. Re ...

Impact pile driving is the predominant foundation technique for offshore wind turbines. The pressure waves generated during pile driving produce high noise levels that can harm marine life. To protect marine mammals, regulations have been established to limit underwater noise. Recent monopile installations already surpass these limits, necessitating noise mitigation measures to proceed with piling operations. As monopiles and hammers grow larger, noise levels are expected to increase further, escalating the need for effective noise mitigation strategies.

The ongoing evolution of offshore technologies makes it essential to understand the behavior and effectiveness of noise mitigation measures and to develop accurate models for predicting their performance. Currently, limited predictive models exist for most noise mitigation techniques, and it remains unclear how their efficiency will be affected by future piling conditions. As monopiles and hammers increase in size, the noise they produce shifts toward lower frequencies, challenging the effectiveness of current mitigation measures.

This study addresses these knowledge gaps by investigating the performance of existing noise mitigation measures under future piling conditions. A numerical model is developed using the Finite Element Method in COMSOL for near-field analysis, coupled with the Boundary Element Method in SILENCE for far-field analysis. Four categories of noise mitigation measures are examined: the bubble-curtain, a resonator-type mitigation screen, an isolation casing, and pulse prolongation. A critical piling scenario -designed to maximize noise propagation- serves as the baseline for analyzing the individual and combined effectiveness of these measures. Additionally, the scenario is re-simulated with softer soil conditions to assess how environmental factors influence mitigation efficiency.

Key findings reveal that most noise mitigation measures are more effective at attenuating higher frequencies. However, as monopiles become larger and stiffer, natural frequencies decrease, while greater hammer strikes and deeper waters enhance the propagation of lower frequencies. These changes result in a general decline in mitigation efficiency for future piling scenarios. Furthermore, the efficiency of each measure is highly dependent on the frequency content and environmental conditions, such as soil stiffness and water depth. For instance, softer soil conditions significantly alter the effectiveness of certain mitigation measures, with some showing improved performance and others becoming less efficient compared to stiffer soil conditions, and the same goes for combinations of measures.

This study highlights the importance of frequency-specific analyses when applying noise mitigation measures. It underscores the need for tailored approaches to ensure effective noise reduction under varying environmental and piling conditions, offering critical insights into the future of noise mitigation in offshore wind development.

Numerical study of wind farm gravity waves: Impact of wind farm configuration

Master thesis (2025) - B.W.M. Comuth, Simon Watson, D. A. von Terzi, Stefan Hickel

Large Eddy Simulation Atmospheric Gravity Waves Wind Farm Layout Froude Number Multi- Scale Coupled Model

The recent growth of the size of wind farms highlights the need for a deeper understanding of the mesoscale phenomena in a stably stratified atmosphere, such as atmospheric gravity waves, as the effect on the power generation can be significant. This thesis is a numerical study o ...

The recent growth of the size of wind farms highlights the need for a deeper understanding of the mesoscale phenomena in a stably stratified atmosphere, such as atmospheric gravity waves, as the effect on the power generation can be significant. This thesis is a numerical study of the effect of wind farm layout on atmospheric gravity wave excitation and the resulting feedback on wind farm performance. Wind farms in this study have varying power density, streamwise or spanwise turbine spacing, aspect ratio, hub height, rotor diameter, shape, or orientation with respect to the freestream, and are situated in a conventionally neutral boundary layer in offshore conditions. Moreover, the wind farms can be horizontally or vertically staggered. To investigate the atmospheric gravity wave excitation, the effect of wind farm layout on the Froude number and inversion Froude number governing the internal and interfacial waves respectively is studied using several high-fidelity Large Eddy Simulations. Then, AGW wavelength and wind farm efficiency are parametrically studied using a fast reduced-order model. Specifically, the non-local efficiency is considered, which is a measure of the global blockage effect induced by the atmospheric gravity waves. It is found that the length scale used in the Froude number must be adjusted to the wind farm, and is dependent on the turbine spacing and farm shape. The inversion Froude number is based on the phase speed of the interfacial waves. It is suggested that the phase speed must be based on shallow-water theory and deep-water theory for small and large turbine spacings respectively. In other words, for small turbine spacings the wind farm acts as an entity, while for large turbine spacings, the farm acts as a collection of individual turbines. Finally, the streamwise and spanwise turbine spacing (and consequently the power density), and the aspect ratio primarily govern the non-local efficiency.

Advanced fUS Signal Processing: Exploiting Full-Detail Data and Frequency Information Through Tensor-Based Blind Source Separation

Master thesis (2025) - J.E. Bakker, Borbála Hunyadi, R. Wijnands, R.C. Hendriks, Pieter Kruizinga

Blind source separation Tensor decompositions Neuroimaging Functional ultrasound Canonical polyadic decomposition

In the last decade, the new functional neuroimaging technique functional ultrasound (fUS) has emerged as a potential new tool for clinical and neuroscientific applications. Unlike several conventional methods for functional brain imaging, fUS offers an unparalleled combination of ...

In the last decade, the new functional neuroimaging technique functional ultrasound (fUS) has emerged as a potential new tool for clinical and neuroscientific applications. Unlike several conventional methods for functional brain imaging, fUS offers an unparalleled combination of submillimeter-subsecond spatiotemporal resolution and the ability to penetrate deep into brain tissue and capture large areas of interest. This makes fUS an exceptionally valuable tool for investigating brain function. The principal physiological mechanism utilized by fUS imaging is neurovascular coupling, which connects neuronal activity with local hemodynamic changes. Within the brain, increased neuronal activity results in the dilation of nearby blood vessels, subsequently leading to an increased local blood flow and volume.
In fUS, the increase in blood volume is measured by the intensity of the Doppler signal caused by the Doppler effect. To obtain relevant information from functional neuroimaging data, blind source separation (BSS) is often used. BSS is the separation of a set of source signals from a set of mixed signals, without the aid of information about the source signals or the mixing process. A commonly used BSS method for identifying brain networks and artifacts in functional neuroimaging techniques like fMRI is independent component analysis, which is a low-rank matrix decomposition. This work explores the use of canonical polyadic decomposition (CPD), a low-rank tensor decomposition, for BSS of fUS data. The CPD approximates a 3rd-order tensor, consisting of a space, frequency, and time dimension, by a sum of rank-1 tensors. The proposed method offers three key advantages that make it highly relevant to the field of fUS signal processing: 1) Tensor-based BSS by CPD allows for frequency as a third dimension to complement the spatial and temporal dimensions; 2) Tensor-based BSS by CPD allows for the use of all raw fUS data (compound images) rather than only power doppler images, exploiting more available information; and 3) Tensor-based BSS by CPD allows for a BSS method without strong constraints such as the case with matrix-based methods like independent component analysis. The full processing pipeline developed in this work consists of four distinct stages. In stage one, pre-processing is carried out through SVD filtering, temporal demeaning, and pixel-based normalization. During the SVD filtering, normalization of the singular values is performed, which is novel. In stage two, compression is performed using truncated multilinear singular value decomposition. In stage three, BSS is carried out using CPD on the compressed data. In stage four, stable components are extracted by running the CPD 100 times and clustering the resulting components. These clusters were then averaged to create mean components. The CPD rank was estimated based on two quantifiable aspects: 1) Correlation between mean components and 2) Frequency of occurrence of mean components. The method is entirely data-driven, can be applied to entire raw fUS datasets, and can run on a laptop with standard RAM. Application to task experiment data of a mouse verified that activity that is temporally correlated with the stimulus can be extracted in expected regions. The components also indicate expected functional connectivity, which is often not the case for matrix-based methods. Moreover, frequency spectra showed different characteristics for different types of components, which displays the relevance of this dimension for BSS, especially for nuisance components. In conclusion, the proposed tensor-based blind source separation pipeline for raw fUS data was able to identify artifacts and meaningful neurological components based on distinctive characteristics in the temporal, spatial, and spectral domains. This work serves as a starting point for more advanced denoising, the identification of novel brain networks, and the comparison of brain networks across healthy and pathological conditions. Nevertheless, further research is necessary to ensure the utility of the method.

What if fanfiction, but also coding: Investigating cultural differences in fanfiction writing and reviewing with machine learning methods

How has the portrayal of female characters in fanfiction evolved in response to the #MeToo movement and fourth-wave feminism, as analyzed with the help of NLP techniques?

Bachelor thesis (2025) - I. Marinescu, Hayley Hung, E. Eisemann, C. Hao, I. Kondyurin

Natural Language Processing Feminism Fanfiction

This paper explores how the portrayal of female characters in fanfiction evolved in response to the #MeToo movement and fourth-wave feminism, with the aim of assessing whether the impact of the awareness of the campaign was broad enough to visibly alter how the average author por ...

Modeling Flapping Dynamics for Tiltrotor Flight Dynamics Applications

Master thesis (2025) - S. de Kok, Marilena Pavel

Flapping Dynamics Tiltrotor Flight Dynamics

Tiltrotor aircraft combine the vertical takeoff and landing capabilities of helicopters with the speed and range of fixed-wing airplanes. Modeling their transitional flight dynamics, particularly the role of rotor flapping, remains a challenge. This paper develops an analytical f ...

Constraining lateral thickness variations in Ganymede with JUICE

Master thesis (2025) - D.L. Calliess, M. Rovira Navarro, Dominic Dirkx, Wouter van der Wal

Tides JUICE Ganymede

JUICE will measure tidally-induced variations in Ganymede's gravitational field with unprecedented accuracy. Previous research focused on studying tides with a spherically-symmetric interior allowing to constrain the mean shell thickness and subsurface ocean. The presence of late ...

Assessment of Electrical Thruster Configurations for Lunar CubeSat Attitude Control

Master thesis (2025) - P. de Lange, A. Cervone, Jian Guo, EJ van Kampen

CubeSat Embedded Systems ESA Lunar ADCS LUMIO Micro-Propulsion SmallSat Vacuum Arc Thruster Spacecraft Design Hardware Testing

This research investigated the application of electrical thrusters within the Attitude Determination and Control System (ADCS) of the European Space Agency’s LUMIO mission, a 12U CubeSat set to op- erate in a quasi-periodic halo orbit around the Earth-Moon L2 point. While CubeSat ...

This research investigated the application of electrical thrusters within the Attitude Determination and Control System (ADCS) of the European Space Agency’s LUMIO mission, a 12U CubeSat set to op- erate in a quasi-periodic halo orbit around the Earth-Moon L2 point. While CubeSats have become pivotal tools for lunar exploration, the use of electrical thrusters for ADCS, particularly in the lunar en- vironment, remains under-explored. This study aimed to evaluate the impact of replacing LUMIO’s current ADCS design by electrical thruster configurations on attitude control performance, robustness, and connectivity, bridging a critical gap in current literature.
A simulation framework was developed to assess spacecraft performance over a two-week period, ex- amining the LUMIO mission reaction wheel set-up, as well as four distinct thruster configurations. Key metrics included thrust output, angular velocity, and pointing accuracy, represented by the half-cone offset angle. In addition, power and energy requirements were investigated. Robustness tests eval- uated system adaptability to single thruster failures, solar array deployment, and high initial angular velocities. Physical validation was achieved by porting the control algorithm to an embedded STM32 Nucleo board, which was connected to a solenoid valve representing a dummy thruster. This setup allowed for real-time testing of execution accuracy, signal fidelity, and system integration.
The results demonstrated that the control algorithm consistently maintained high pointing accuracy, keeping the half-cone offset angle within the mission requirement of 0.18 [◦]. Reaction wheels and electrical thrusters effectively generated the required control torques, with negligible angular momen- tum build-up in the nominal simulation. Overdetermined thruster configurations showcased enhanced energy efficiency, reducing total energy consumption by approximately 29% compared to determinate setups. However, the study also highlighted challenges, such as the minimum impulse bit constraints of the Pocket Rocket thrusters, which limited precise low-thrust operations.
Robustness tests revealed that determinate configurations failed to accommodate single thruster fail- ures, while overdetermined systems adapted effectively, albeit with increased power demands. From the results, it is recommended for any space mission to be certain that the on-board computer is aware of any thruster fail occurring. The undeployed solar array configuration significantly reduced energy re- quirements, supporting its feasibility for early mission phases. The thruster configurations showed not to be able to realistically counteract de-tumbling manoeuvres, significantly degrading their feasibility in the actual LUMIO mission. Additionally, the embedded system validation confirmed accurate command signal generation and execution, bridging the gap between simulation and real-world implementation.
Although the electrical thruster configurations adhered to pointing accuracy requirements in nominal simulation conditions, they impose significantly higher power and energy demands and are unable to counteract high de-tumbling manoeuvrers compared to the current reaction wheel configuration in the LUMIO ADCS design. Addressing main engine parasitic torques and exploring alternative, higher- performance thrusters may offer a feasible solution for integrating electrical propulsion into lunar Cube- Sat ADCS. While the reaction wheel and non-electrical thruster combination remains the preferable option for now, this research demonstrates the potential for electrical thrusters in advancing CubeSat capabilities. Future studies should build upon this foundation by addressing current limitations, extend- ing simulation durations, and exploring innovative propulsion technologies to unlock their full potential in deep-space missions.

Automated Localisation of Subject-Specific Muscle-Tendon Paths of the Lower Limbs Using nnU-Net on Magnetic Resonance Images

Master thesis (2025)

Parameter estimation Muscle modeling Subject-specific Musculoskeletal Modeling

Muscle-tendon paths vary between individuals, and musculoskeletal models show sensitivity to these variations when estimating muscle and joint forces. Accurate estimations of these internal forces allow for a more comprehensive approach to researching debilitating musculoskeletal ...

Implementation and evaluation of the shifted fracture method for crack propagation in fiber-reinforced polymer composites

Master thesis (2025)

Crack propagation Cohesive zone modeling Mesh dependency Shifted fracture method Fiber-reinforced polymer composites

Fiber-reinforced polymer (FRP) composites are used in various engineering applications due to their many advantageous properties, but predicting failure remains challenging due to complex failure behavior. The Computational Mechanics group at TU Delft uses an inter-element cohesi ...

Fiber-reinforced polymer (FRP) composites are used in various engineering applications due to their many advantageous properties, but predicting failure remains challenging due to complex failure behavior. The Computational Mechanics group at TU Delft uses an inter-element cohesive zone method, referred to as the Ortiz model, to analyze microscale crack propagation. Although effective for modeling complex failure processes, the method suffers from severe mesh dependency, restricting large-scale simulations. This research implements and investigates the shifted fracture method (SFM) as an alternative to reduce mesh dependency while maintaining computational complexity. The SFM modifies key aspects of the Ortiz model, including an area correction term, crack propagation algorithm, and shifted weak form equations and cohesive zone conditions using Taylor expansions. Three versions of the SFM were tested: (1) full SFM implementation, (2) reduced SFM with only the area correction and crack propagation algorithm, and (3) an extended Ortiz model with only the area correction term. Numerical simulations show that the reduced SFM is robust, mesh-independent, and efficient in basic fracture tests. The area correction term proved critical in reducing mesh dependency. The extended Ortiz model, on the other hand, showed less accurate results in predicting cracks, despite the additions of the area correction term. Furthermore, the maximum principal tensile stress criterion for determining the crack direction was unsuitable for mixed-mode scenarios, resulting in inaccurate paths. Although the reduced SFM shows promising results, it requires further development to handle complex fracture scenarios like FRP composites. Features such as crack initiation, merging, and termination were implemented and showed potential but require further validation. This research concludes that while the reduced SFM is effective for basic testing, further refinements are needed for broader application to FRP composites.

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