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.

Modelling changing travel behaviour in response to road capacity reductions

The impact of reallocating road space in urban areas on car use

Master thesis (2025) - S.A. van Heyningen, M. Snelder, VL Knoop, R.T.J. van der Kleij

Car use reduction Disappearing traffic Road capacity reductions Road space reallocation Modelling changing travel behaviour Low-car city

As cities increasingly prioritize sustainable and low-car urban environments, road capacity reductions have become a widely applied policy measure. While traditional transport models predict severe congestion resulting from such interventions, empirical studies suggest that traff ...

Utilizing cross-modal correspondences to select fragrances

D'Accord

Master thesis (2025) - A. Strijker, M. W.A. Wijntjes, C.R.G. Smit

Multi-sensory design Experience Design Cross-modal perception Scent

The retail perfume industry often lacks the multi-sensory engagement needed to frame the perception of a fragrance and thus facilitate the fragrance selection process. Scent is very ambiguous and needs cues from other senses to better place a scent (Pierzchajlo et al., 2024). Thi ...

Wake Re-Energization of a Scaled Wind Farm via the Use of Lifting Devices: An Experimental Study

Master thesis (2025) - M.J. Fijen, A Sciacchitano, YuanTso Li, Carlos Simao Ferreira

Wake recovery Wake redirection Wind turbine wake losses Re-Generative Wind Farming Wind farm aerodynamics Particle Tracking Velocimetry (PTV) Downstream turbine performance Lifting devices

The development of offshore wind farms has demonstrated significant value in harnessing renewable energy sources. However, the offshore wind energy sector faces increasing challenges, making the realization of new wind farms a greater financial risk. This has reached the point wh ...

The development of offshore wind farms has demonstrated significant value in harnessing renewable energy sources. However, the offshore wind energy sector faces increasing challenges, making the realization of new wind farms a greater financial risk. This has reached the point where several high-profile offshore wind projects have been halted. A key contributor to these struggles is the aerodynamic effect of wind farm wake losses. As wind turbine sizes increase, costs rise, but the wind farm concept limits energy yield. This is due to slow wake recovery behind turbines, causing downstream turbines to only be able to harvest energy from low-momentum flow. Based on the literature review conducted, the methods to improve wind farm efficiency by reducing wake losses, such as wind farm layout optimization and rotor yawing or tilting, only partially address the problem.

The concept of regenerative wind farming, proposed by Ferreira, seeks to provide a solution. This involves integrating lifting devices into wind energy harvesting systems that can redirect the wake vertically, enabling the flow from higher atmospheric layers to contribute more to the wake recovery process. Such interactions can dramatically enhance the energy that is replenished into the wind farm, offering a promising approach to overcoming these challenges.

This research aims to evaluate the potential of the novel wind farm concept, regenerative wind farm, through a scaled wind farm experiment. In the scaled wind farm, there are nine wind energy harvesting systems, which are aerodynamically modeled by using porous disks and wings. The study focuses on the far wake and the performance of downstream turbines. The experiment was conducted in the Open Jet Facility (OJF) at TU Delft. The flow field was measured using Particle Tracking Velocimetry (PTV) with Helium-Filled Soap Bubbles (HFSB), and load measurements were accompanied.

Load measurements revealed that thrust values for downstream turbines increased by more than three times when lifting devices were attached to the actuator surfaces. Also, flow field data showed significantly higher wake velocities, as potent vertical flows in the wake regions were induced by the tip-vortices of the wings, which enhanced vertical energy entrainment. This vertical motion actively entrains the flow above the wind farm, allowing high-momentum air to enter the wind farm layer, something that does not occur without the wings. Additionally, the lifting devices reduce turbulence intensity in the rotor projection area at the downstream end of the wind farm, helping to lower the fatigue loading of downstream systems. An investigation of a misaligned row confirmed that the concept remains effective even under such conditions.

This work demonstrates that the regenerative wind farm concept holds great potential to enhance wind farm power output while reducing the required wind farm area. With this concept, wind turbine wake losses are effectively mitigated by entraining high-momentum flow into the wind farm.

SMURF: a Methodology for Energy Profiling Software Systems

Simulate and Measure to Understand Resource Footprints

Master thesis (2025) - O.K.N. Kaaij, Luis Cruz, J. Sallou, Arie Van 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 ...

Navigating the luxury goods market through the reputation renaissance

Master thesis (2025) - I. Kool, Erik-Jan Hultink, E.H.I. van Vught

Cultural capital Luxury brands Brand reputation Reputation recession & renaissance Instagram engagement Multimodal thematic analysis Brand coolness

The reputation of personal luxury brands has undergone a significant transformation since 2018, with the industry experiencing a reputation recession followed by an uneven reputation renaissance. This shift underscores a deeper misalignment between luxury brands and the evolving ...

The reputation of personal luxury brands has undergone a significant transformation since 2018, with the industry experiencing a reputation recession followed by an uneven reputation renaissance. This shift underscores a deeper misalignment between luxury brands and the evolving values of the new luxury consumer. Millennials, soon set to dominate the luxury market, have accelerated this change. Their engagement with brands on Instagram not only shapes brand perception but also reflects their shifting interests. As social media become central to shaping brand reputation, analysing these engagement patterns offers critical insight into the preferences of the new luxury consumer.

This study examines how successful and struggling brands manage their reputation through content and engagement practices on Instagram. Using a hybrid research approach, it integrates quantitative engagement metrics with qualitative multimodal thematic analysis conducted on six luxury brands (three successful and three struggling) between 2021 and 2023, marking the onset of the reputation recession. To guide the exploratory nature of this study, an integrative framework of brand reputation was developed to synthesise company-controlled, consumer-controlled, and co-created reputation factors. The findings reveal that successful brands leverage cultural capital, particularly through collaboration with South Korean pop culture figures, to enhance brand coolness and foster deeper emotional connections. Struggling brands fail to establish these connections, relying on conventional celebrity endorsements that lack subcultural appeal, leading to continued reputation challenges.

By analysing only the most and least liked posts on Instagram, subtle engagement strategy adjustments could not be identified. Additionally, excluding comment data limited deeper sentiment analysis. Moreover, this research investigates a symptom of a deeper underlying issue caused by a changed luxury consumer. Future research should explore consumer sentiment through the comment section, expand the dataset to detect brand coolness life cycle transitions and most importantly, examine the values of the new luxury consumer that shape their purchasing behaviour. Despite these limitations, this research contributes to brand reputation literature by bridging fragmented studies into a cohesive framework for evaluating brand reputation factors. For luxury brands, the reputation dashboard provides a structured framework that identifies one of these factors, brand coolness, as a competitive advantage to strengthen consumer loyalty, word-of-mouth, and brand equity. Finally, transforming an once-abstract and intangible concept into a tool for business strategy.

Bicycle battery pack with replaceable pouch cells

Master thesis (2025) - F.A. Wilschut, M. Slingerland, A.R. Balkenende

Reversible connection Replaceable pouch cell Bicycle battery pack Reconfigurable modules Sub-cells

This report covers the findings and considerations for the development of a reconfigurable bicycle battery pack with replaceable pouch cells.

On the path to net zero, electric vehicles will play a major role in the energy transition. As a result, battery demand is expect ...

This report covers the findings and considerations for the development of a reconfigurable bicycle battery pack with replaceable pouch cells.

On the path to net zero, electric vehicles will play a major role in the energy transition. As a result, battery demand is expected to rise significantly in the coming decade. To reduce the need for critical materials and prevent e-waste, it is essential to establish circular supply chains and implement effective end-of-life strategies.

Bicycle batteries consist of multiple cells, yet entire battery packs are often discarded when only a few cells fail, despite the remaining cells being perfectly reusable. One of the reasons is the excessive use of glue and solder in battery pack designs, which complicates both reuse and recycling.

In partnership with EAGLEBAT, this report explores the development of a battery pack that allows for the replacement of individual cells. Additionally, the design utilises pouch cells developed by EAGLEBAT instead of the conventional cylindrical cells typically used in bicycle batteries.

First, the context of battery design is explored, with a focus on existing bicycle batteries, their disassembly challenges, and their safety features. This phase also includes a comparison of pouch cells with other cell types, an introduction to EAGLEBAT’s pouch cell technology, and an evaluation of alternative joining techniques to replace soldering.

Second, boundaries are established to define the scope of the battery design. A vision for a reconfigurable system based on 12V modules is introduced, followed by the selection of a Battery Management System structure and an overview of the 12V module’s cell layout. Finally, design principles are formulated.

Third, ideation is started by dividing the design problem into sub-problems. Solutions for each sub-problem are generated and consequently compiled into a morphological chart. This chart, guided by design the design principles, serves as the basis for developing initial concepts. After evaluating these concepts, the focus shifts to the challenge of creating a durable, reversible tab connector. Three tab connector options are explored and through the DATUM method, the laser-welded flexible PCB tab connector is selected as the most suitable.

Ultimately, a final design concept is proposed as a demonstrator, integrating previous insights from the project. The laser-welded flexible PCB tab connector plays a central role in this design concept. The design is elaborated at cell, module, and battery pack levels, concluding with an evaluation of its overall performance.

The report then ends with a discussion of the project and with several recommendations toward the realisation of the design.

Modelling of a gas generator powered mortar parachute deployment device

Simulation Tool

Master thesis (2025) - C.D.P. Gueudet, SR Turteltaub, Ashwyn Groot

Gas generator Deployment mechanism Aerospace Parachute

This thesis was conducted within Aerospace Propulsion Products, a company specialized in rocket engine igniters and Parachute Deployment Devices (PDDs) for space applications. The objective of this research was to develop a high-fidelity numerical model in Python capable of accur ...

This thesis was conducted within Aerospace Propulsion Products, a company specialized in rocket engine igniters and Parachute Deployment Devices (PDDs) for space applications. The objective of this research was to develop a high-fidelity numerical model in Python capable of accurately predicting the performance of a PDD system. Given input parameters such as component geometry, propellant load, material properties, and environmental conditions, the model serves as a predictive tool to assist engineers in designing and optimizing PDDs for future planetary exploration missions. To achieve this, an extensive study of parachute ejection mechanisms was first conducted, analysing the physical principles governing gas generator combustion, gas flow dynamics, structural interactions, and aerodynamic forces. A numerical model was then formulated using fundamental principles of combustion, ballistics, physics, and thermodynamics, incorporating detailed representations of the gas generator, plenum, and parachute pack. Once developed, the model was calibrated using experimental data and systematically verified and validated against deployment tests to assess its accuracy in predicting key performance metrics such as pressure profiles, reaction forces, and ejection velocity. The validated model was then subjected to a sensitivity analysis to identify the most influential parameters affecting system performance. The results demonstrated that parameters such as the discharge coefficient, chamber volumes, plenum dimensions, and propellant loading significantly impact the pressure buildup, deployment timing, and ejection dynamics. Additionally, variations observed in experimental repeatability highlighted the inherent uncertainties in physical testing, further emphasizing the value of numerical modelling in PDD development. By providing a robust and accurate simulation framework, this research contributes to the advancement of next-generation PDD systems. The model developed in this study offers engineers a powerful tool for optimizing PDD designs, ensuring reliable deployment performance across various mission scenarios. Future work will focus on further refining the model by incorporating additional experimental data and extending its applicability to a wider range of deployment conditions.

Synthetic X-Ray Image Generation Using FPGA-Based Hardware Acceleration

Master thesis (2025) - P.J. Aanhane, Rob de Jong, Z Al-Ars

FPGA Philips X-ray Hardware Acceleration

Synthetic image generation involves the creation of artificially generated images that are indistinguishable from real ones. This field is an answer to challenges in the world of data acquisition, where the need for data is outpacing the availability. In cooperation with Philips ...

Synthetic image generation involves the creation of artificially generated images that are indistinguishable from real ones. This field is an answer to challenges in the world of data acquisition, where the need for data is outpacing the availability. In cooperation with Philips Medical Systems, the generation of synthetic X-ray images is studied. Using datasets derived from such images, equipment testing and physician training can be improved. Additionally, training data can be generated for machine learning purposes.

The generation of synthetic X-ray images has been an area of research since at least 1994. The images have traditionally been generated using ray-tracing techniques on CPUs or GPUs. While effective, these methods are computationally expensive and demand high memory bandwidths. More recently, machine learning techniques have been explored for X-ray image generation. These approaches are promising. However, they require large labelled datasets which are often unavailable and the quality of the results is difficult to predict.

The aim of this thesis is to investigate whether hardware acceleration using a field programmable gate array (FPGA) can solve the challenges other methods face. Specifically, it discusses an architecture that can handle the large amount of computations in parallel. The memory architecture required to handle the high bandwidth demands is also explained. The performance of the proposed architecture is studied to see whether it is a viable solution.

By simulating the traversal of rays through a voxelized model, an attenuation map was computed which can be used to determine X-ray intensities on a detector. The design separates computational tasks between a host machine and an FPGA, with an optimized High Bandwidth Memory architecture to maximize data throughput. Results demonstrated that the simulation produced realistic images with minimal error (2.26\% - 3.00\% deviation from CPU results), and performance is dependant on the detector resolution, achieving frame rates between 123 and 378 frames per second which are well above the goal of 60 frames per second. If more performance is required, upsampling can be used to speed up image generation by 33\% at an increased error of 0.6\% for an upsampling factor of two. These findings highlight the advantages of FPGA acceleration for deterministic, high-speed synthetic image generation without the need for large labelled datasets as required by machine learning algorithms.

Towards Generative AI-powered Engineering of Critical Systems

Reverse Engineering Tool for Knowledge Based Engineering Applications & Ideation Matrix for AI-powered Automation Systems

Master thesis (2025) - J.P. Koopman, G la Rocca, Caroline Wehrmann, Steven M. Flipse, Leo L.M. Veldhuis, Alexander Heidebrecht

Explainable AI Large Language Models (LLMs) Communication Design Science Communication Generative Artificial Intelligence Knowledge-Based Engineering Reverse Engineering Model-Based Systems Engineering (MBSE) Interdisciplinary Collaboration Engineering process Communication Tool

The integration of Generative Artificial Intelligence (GenAI) in engineering presents both opportunities and challenges, particularly in complex, safety-critical systems. This thesis explores two key aspects: (1) developing an AI-powered reverse engineering tool for Knowledge-Bas ...

Prepared Care for Discharge

Designing the First Steps to Improve the Hospital Discharge Process for Oncology Patients and Their Close Loved ones

Master thesis (2025) - T.R. Biervliet, F Sleeswijk Visser, Armagan Albayrak, Petra Kok

Healthcare Experiences Oncology Empathy in Design Hospital Discharge Discharge Journey Map

Patients staying in the oncology department have to deal with fears and worries about their treatment, diagnosis and the effects it brings on their life and those around them. These fears and worries remain often hidden, due to patients needing time to open up about them and heal ...

Patients staying in the oncology department have to deal with fears and worries about their treatment, diagnosis and the effects it brings on their life and those around them. These fears and worries remain often hidden, due to patients needing time to open up about them and healthcare providers not immediately noticing these. They take these fears and worries with them when leaving the hospital, creating a negative discharge experience that provides a lot of stress in a setting where they can familiarize themselves again. The current discharge takes a clinical approach that favors time efficiency with a focus on the direct patient’s needs while missing out on discussing hidden fears and worries of the patients, and no new knowledge is provided on how to effectively do this. This asks for new approaches and tools that can make these hidden fears and worries noticed by healthcare providers, being able to talk about them and prepare the patients and their close loved ones to leave the hospital with a confident feeling of being able to take care of themselves and provide the care necessary. This project aims at finding such new approaches and providing tools that can help turn the discharge experience more positive. A mixed method approach is used where in four phases the context of the oncology department is explored, analysed and designed for. This is supported by an empathy framework, discharge journey map and other models in order to provide a human soft touch to the discharge process. A good understanding of the current discharge process is formed and insights are gathered that influence the discharge experience. Concepts are created that incorporate the insights to evaluate the effects on the discharge process. The hidden fears and worries of patients and their close loved ones are the care not being of the same quality outside the hospital as within, their home turning into a second care home and them not being able to take care or provide the care. Healthcare providers hold on to their existing working methods due to their attitude of it working for some time without any form of self-reflective feedback. Six factors have an influence on the discharge experience that determine how everyone involved interacts with each other, of which confidence and expectations can be improved. A concept goal and direction are formulated that focus on the two factors and additionally raise awareness, allow everyone to share their fears and worries and give confidence to be able to take or provide care. This has given two concepts which in a total of six tests have been evaluated on their influence and changes to the discharge process. A final concept proposal is given with an implementation plan for future design that expands on the first steps created in this project.

Flood Resilience Quantification based on Hydrodynamic Conditions

A case study of the Ablasserwaard in The Netherlands

Master thesis (2025) - M.R. Kerver, J.P. Aguilar Lopez, Olivier Hoes, S.H. Buitrago Díaz, T. Berends, E. Benschop

Resilience Alblasserwaard 3Di Flood Resilience Hydrodynamic Conditions Multi-Layered Flood Safety

Flood risk management has traditionally been centered around economic damages and casualty assessments, providing a basis for preventive measures like levees. However, with increasing climate change-induced weather extremes, a shift toward flood resilience is necessary. This shif ...

Flood risk management has traditionally been centered around economic damages and casualty assessments, providing a basis for preventive measures like levees. However, with increasing climate change-induced weather extremes, a shift toward flood resilience is necessary. This shift involves accepting some level of flooding while enhancing system recovery and damage mitigation. Existing resilience frameworks offer only qualitative insights or rely on significant assumptions, limiting their applicability in objective assessments.

This research focuses on addressing the challenges of quantifying flood resilience, a concept inherently complex due to its multi-layered nature and reliance on diverse perspectives. By incorporating hydrodynamic conditions such as water depth, flow velocity, and momentum, alongside local topography and land use, this study aims to propose metrics that better capture the temporal and spatial dynamics of flood resilience. This enables objective evaluation of mitigation measures, guides resource allocation, and facilitates informed decision-making for engineers and policymakers alike. This could subsequently enhance flood risk frameworks and increase flood safety in The Netherlands.

A methodology for quantifying flood resilience through hydrodynamic modeling is presented in this study. It identifies functionality variables like temporal water depth, temporal impact, number of flooded buildings, and percentage dry area as central to assessing resilience. From these functionalities, resilience metrics are derived, like shock amplitude, arrival time, and residence time.

The methodology is tested through a case study in the Alblasserwaard. The study uses 3Di modeling software to simulate flooding scenarios and evaluate the applicability of resilience measures. This is done through model variations and interventions such as detention basins, moveable barriers, and enhanced pumping capacity. The chosen case study includes diverse land uses, enabling the assessment of resilience across residential, economic, and ecological perspectives.

The metrics of shock rate, residence time, flood arrival time, and flooded utilities provide promising insights into flood resilience. The derivative shock rate evaluates emergency response service capacity, while residence time assesses damage extent and recovery time. Adding indirect hydrodynamic conditions, like nearby flooded roads and utilities, further enhances system understanding in the provided case study. Different perspectives highlight the variability in suitable metrics as well as suitable interventions.

However, some metrics require further research or modification. The depth integrals show potential during shock and recovery, but they lose information when used as a linear metric between time and water depth. The flooded utilities metric provides valuable insights but needs expansion to accurately reflect flooding consequences. The momentum impact metrics are unsuitable for the current model due to limitations in 3Di’s flow velocity calculations.

While the method proved feasible for identifying and comparing
resilience in a specific system, further research is needed to address uncertainties, refine metrics for indirect effects, and test applicability beyond the presented case study. This framework represents a further development toward a comprehensive, objective approach to flood resilience, supporting effective, adaptable flood
management solutions even under the continuous threat of increased climate extremes.

Striving towards a shorter security queue

A stated choice experiment on the timeslot reservation system at Schiphol Amsterdam Airport

Master thesis (2025) - T.J. Hillenaar, EJE Molin, A. Verbraeck

Factor analysis Discrete event simulation Airport MNL model Stated preferences Discrete choice experiment Peak Shaving Willingness-to-pay Security Time Slots

This thesis researches passenger preferences regarding the security time slot reservation system at Schiphol Airport. This study is motivated by the fact that time slots are currently used less than expected by Schiphol, while time slots aught to be one of the solutions for the r ...

This thesis researches passenger preferences regarding the security time slot reservation system at Schiphol Airport. This study is motivated by the fact that time slots are currently used less than expected by Schiphol, while time slots aught to be one of the solutions for the rising number of passengers, which cause more pressure on several systems at the airport, including the security checkpoint.

The main goal of this thesis is: "to investigate passengers’ preferences of a security time slot reservation system at Schiphol Airport. Additionally, the study aims to identify the optimal balance between travellers with and without a time slot for the security check point to ensure system effectiveness." Through a survey that includes both a Stated Preference Analysis and a Factor Analysis, passenger preferences are researched. In addition, a discrete event simulation is done in order to explore possible scenarios for time slot usage.

The research shows that passengers who book a time slot tend to have a more favourable view of the system than those who do not have a reservation. While having time slots brings more certainty to catch your flight, it can also limit flexibility, which some travellers see as a downside. Stress levels vary between these two groups, with those using time slots reporting less stress because they know what to expect due to time slots. However, people who are not familiar with the time slot system often remain sceptical, underlining the need for better awareness to change these perceptions.

When it comes to passenger preferences, the time between security checks and departure plays a crucial role in deciding whether to reserve a time slot. The study indicates that passengers find the most value when this time is less than 100 minutes, with the benefits decreasing as this time increases. Cost sensitivity is another important factor, as passengers react strongly when a previously free service becomes a paid one. On the other hand, their sensitivity is less strong for potential price increases. A similar trend is seen with saved waiting time, where the first few minutes saved are more valuable than larger time savings. Business travellers and passengers travelling with children tend to be less cost-sensitive, likely due to company support or a focus on convenience. Moreover, Schengen passengers are more likely to book time slots when the time between security and departure is short, while non-Schengen passengers have a less strong preferences towards short time slots.

The scenario analysis indicates that adding more security lanes can help reduce waiting times, but this effect is less strong when queues are already short. The study also finds that having dedicated security lanes for time slot passengers is not very efficient unless a large number of passengers are using them. Instead, a mixed strategy (with other types of lanes, such as priority class) is suggested to enhance efficiency. Additionally, peak shaving, which involves spreading out passengers across different time slots, is shown to be an effective method for managing queue lengths and improving overall flow.

Feeling Home

Opening up to the variety of flavours of living together in Woonontwikkeling Vredeoord

Master thesis (2025) - S.A. Bakker, Froukje SleeswijkVisser, S.C.M. Brand-de Groot

Social Design Social design intervention Empathy in Design

The assignment for this graduation project was to develop a tool for residents to “step into each other’s worlds”. The project is a side track of the Bubble Games project, here VR technology is used to let people step into each other’s world to understand each other better. My ch ...

The assignment for this graduation project was to develop a tool for residents to “step into each other’s worlds”. The project is a side track of the Bubble Games project, here VR technology is used to let people step into each other’s world to understand each other better. My challenge was to develop such a tool, but without using VR technology. Through research about the neighbourhood, including interviews with residents and professionals, the assignment was reformulated into developing a tool that guides residents of Woonontwikkeling Vredeoord to open up to the different flavours of living in together in their neighborhood.

Throughout the project, stakeholders were actively involved. During the design phase, multiple prototypes were created and tested with residents. A brainstorming session with residents helped defining the concept direction, resulting in Babbeloord.

Babbeloord is a phonecell where users are guided through different tasks via a phone. First, you discover your own needs regarding living together in the neighbourhood through the fundamental needs cards on the wall. Then, they are asked to explain their needs, to then listen to the stories of their neighbours. At the end, a question is asked about what they have learned from this chat (Babbel), encouraging residents to reflect. This question is also displayed on a mirror hanging on the third wall of Babbeloord. Follow-ups take place after two and six months to inform residents about the insights gathered and how they will be used.

Babbeloord encourage residents to think about what they believe is important about living together. Babbeloord also provides valuable insights for the municipality. Since Babbeloord was designed for and with residents, it fits well within the neighborhood. The stories collected can provide new entry points for the municipality to act upon. Babbeloord was evaluated in the neighbourhood and validated with two residents who participated in this test. Furthermore, it was discussed with professionals working in the neighbourhood and colleagues from the municipality. These chats provided valuable insights for recommendations on the future use of Babbeloord.

Implementing Location-Optimal Battery Storage in the Dutch Energy System

A case for the Dutch Transmission System Operator TenneT

Master thesis (2025) - J.R. Bleys, K. Bruninx, Geertje Bekebrede

Renewable energy Dutch electricity grid Transmission System Operators Energy system modeling Spatial optimization Socio-Technical systems Battery Energy Storage Systems,

This study investigates the impact of spatial constraints and economic land-use considerations on the optimal placement of large-scale Battery Energy Storage Systems (BESS) within the Dutch high-voltage (HV) grid. In the rapid transformation of the Dutch electricity system—charac ...

This study investigates the impact of spatial constraints and economic land-use considerations on the optimal placement of large-scale Battery Energy Storage Systems (BESS) within the Dutch high-voltage (HV) grid. In the rapid transformation of the Dutch electricity system—characterized by an increasing penetration of variable renewable energy sources (vRES) and a rising need for grid flexibility—BESS have emerged as a pivotal technology for congestion management, renewable integration, and frequency regulation. However, the absence of a systematic strategy for BESS siting creates inefficiencies in grid planning, escalates system costs, and introduces uncertainty for both market participants and the Transmission System Operator (TSO), TenneT.

To address this gap, the research poses the primary question: “What is the impact of spatial constraints and economic land-use considerations on the optimal placement of large-scale BESS from the perspective of the TSO in the Dutch HV grid?” This is further subdivided into three sub-questions: (1) identifying the key considerations in the BESS development and placement process as derived from academic literature and expert interviews; (2) assessing how restrictions related to competing land uses and exclusion zones affect optimal BESS placement; and (3) evaluating the influence of incorporating land costs on BESS siting outcomes.

The study employs a mixed-methods approach, integrating a comprehensive literature review, expert interviews with TenneT representatives and market participants, and an optimization model implemented in PyPSA-Eur. The model simulates BESS deployment scenarios under two temporal snapshots—2023, reflecting current grid conditions, and 2040, a future state with high electrification and stringent decarbonization targets. Three scenarios are analyzed: a BASE scenario with minimal spatial restrictions, a COL scenario that factors in regional land costs, and an EXCL scenario that enforces strict spatial exclusion zones.

Results from the 2023 analysis indicate that enforcing exclusion zones leads to a 43% reduction in deployable BESS capacity, with land costs exerting a relatively minor impact. In contrast, the 2040 simulations reveal a heightened dependency on BESS for grid stability, where the EXCL scenario still reduces capacity by 19%. Notably, certain nodes that initially received minimal BESS allocation under strict spatial constraints later demonstrate a significant increase in capacity, underscoring an intrinsic system requirement for storage despite suboptimal placement conditions.

Further findings highlight the grid’s adaptive responses, including the expansion of cross-country high-voltage direct current (HVDC) connections, particularly between the Netherlands and Great Britain, and stable average line loading and peak frequency metrics. These outcomes suggest that while spatial constraints influence the localization of BESS, the overall grid performance can be maintained through alternative measures such as transmission expansion and flexible generation.

The study concludes with policy recommendations advocating for a national BESS deployment roadmap, streamlined permitting processes, and differentiated grid connection fees to prioritize locations that maximize system benefits. This research bridges the gap between energy infrastructure planning and land-use policy, offering actionable insights for TSOs, BESS developers, and policymakers to foster a resilient, cost-effective, and spatially integrated energy system.

Integration of Pedagogical Agent in Counselling Simulation Training For Child Helplines

Master thesis (2025) - M. Elasmar, W.P. Brinkman, Mohammed Al Owayyed

Scaffolding Training Simulation Child Helplines Pedagogical Agent

Child helplines provide a platform for children facing serious challenges, allowing them to share their stories and receive emotional support and guidance through counselling sessions. To ensure that volunteers are well prepared for these interactions, effective training programm ...

Facade of the Future

A Regenerative Solution for Urban Areas

Master thesis (2025) - N.M. de Graaf, S. Parisi, J.R. Alferink

Regenerative Design Biocomposites Facade Design Environmental Impact

Urban areas are facing more and more challenges these days, such as the Urban Heat Island Effect, the loss of biodiversity, extreme rainfall and unsustainable resource use.
This project aims to design a solution: a regenerative facade panel. The Material Driven Design Method ...

A Study on a Passive Scalar Approach

Master thesis (2025) - P.G. van de Ven, Marc I. Gerritsma, Praneeth Chilakalapudi, Hieu Nquyen

Simulation Contamination DSMC SPARTA Rarefied gas Passive scalar Particle based

With the ever-growing semi-conductor market the need for more advanced and faster chips rises. To keep the steady trend of Moore’s law going, which states that the transistors on a microchip double every two years, the micro chip manufacturing processes have to become more and mo ...

With the ever-growing semi-conductor market the need for more advanced and faster chips rises. To keep the steady trend of Moore’s law going, which states that the transistors on a microchip double every two years, the micro chip manufacturing processes have to become more and more precise. The current state of the art Extreme Ultra Violet Light (EUV) lithography systems produced by ASML can manufacture chips with precision of printing up to 2 nanometers. At these scales even the smallest particles can affect the production processes of chips.
To circumvent the interference of molecules or debris in lithography machines flow simulations are performed to determine how to design flows to clear out these contaminants. Since most areas of the EUV machine are under rarefied gas conditions, normal continuum approaches fall short to predict the flow conditions. For rarefied flows the Direct Simulations Monte Carlo (DSMC) solver called SPARTA (Stochastic Parallel Rarefied-gas Time-accurate Analyzer) can be used. There are more methods to model rarefied gas flows, however the SPARTA program is open-source, adaptable and scales well on parallel computing systems. The last one of the three implies that simulations can be accelerated on High Performance Computing (HPC) clusters. Although the parallel computing accelerates the process, the simulations remain expensive. For instance, the 3D simulation of a scanner section contains 1 billion particles and needs a simulation power of 2000 cores for upwards of 45-80 hours of simulation time.
Consequently, it is necessary to continually develop methods to reduce computational costs for gas flow simulations. In particular cases where the contaminant concentration is so low that the effect of contaminants on the carrier gas can be neglected. In such cases the effects of a flow field on the contaminants can be passively modelled, and this method was dubbed the name Passive Scalar Approach (PSA). In other words, there are no carrier gas particles to actively participate in the collisions. The objective of this thesis is to reduce computational costs of a rarefied gas simulation with DSMC method on SPARTA by means of the PSA method.
First, the PSA capabilities were added to the SPARTA code. The PSA was implemented such that the steady-state background flow for a specific flow domain is first generated. Once this background flow field is imported into SPARTA, the contaminants can be loaded on top of the background flow with various concentrations, distributions, and at various locations within the simulation domain. The interactions between the contaminant and the background flow within every simulation cell is determined by the stream velocity of the background file, temperature and the velocity of the contaminant particles, using a Variable Soft Sphere (VSS) collision model. No active carrier gas particles need to be loaded into the memory of the solver.
Next, the PSA method was compared against a DSMC simulation with active carrier gas particles (referred to as a “full DSMC simulation”) for two cases: 1. Brownian motion in a box with homogenous carrier concentration, and 2. contaminant injection in a Poiseuille flow. Both cases showed similar diffusion rates indicating that the PSA models the full DSMC. In the Poiseuille flow case, an additional molecular scattering analysis showed similar scattering behaviour to the full DSMC collision model on a microscopic level. A significant decrease in computational costs was noted for the PSA in both cases. The findings in this thesis describe the promising results of implementing the PSA to model rarefied aerodynamic behaviour in SPARTA, with significant computational gains.

On-Board Correction Estimation for LEO-PNT Satellites

Master thesis (2025) - J.S. Oduber, J. van den IJssel, Lotfi Massarweh

GNSS Precise point positioning (PPP) Precise orbit determination (POD) Sentinel-6 LEO-PNT

Global Navigation Satellite Systems (GNSS) have become crucial for providing Positioning, Navigation, and Timing (PNT) services worldwide. Existing GNSS constellations such as GPS, GLONASS, BeiDou, and Galileo operate in Medium Earth Orbit (MEO) at around 20,000 km altitude. Low ...

Artificial Reefs: Effects on Wave Transformation and In-Canopy Flow

Insights from Large-Scale Wave Flume Experiments of a Fringing Reef

Master thesis (2025) - K. Albers, Marion F.S. Tissier, Robert McCall, Stuart Pearson, Ad J.H.M. Reniers, Floortje Roelvink, Samantha Haage

Wave Transformation Physical Model Tests Artificial Reef Coral Reef Coastlines Nearshore Hydrodynamics In-Canopy Flow Wave Flume Experiments

Coral reefs play a crucial role in coastal protection and ecosystem sustainability. However, they face increasing threats from sea-level rise, ocean warming, and acidification. While coral reef restoration is often proposed as a means to reduce coastal hazards, there remains insu ...

Coral reefs play a crucial role in coastal protection and ecosystem sustainability. However, they face increasing threats from sea-level rise, ocean warming, and acidification. While coral reef restoration is often proposed as a means to reduce coastal hazards, there remains insufficient field evidence or large-scale laboratory data to validate this claim. A key aspect in assessing the effectiveness of reef restoration is understanding the flow structure within artificial reefs, as wave energy dissipation is closely tied to these dynamics. Not accounting for in-canopy flow in numerical models can lead to inaccuracies in predicting wave dissipation and water level changes.

This thesis investigates wave transformation and dissipation through large-scale wave flume experiments conducted at Deltares' Delta Flume. The experiments utilized a 1:3 scale model of a Maldivian fringing reef, tested under five wave conditions and two water levels. The experimental setup included a 45-meter-wide reef flat, where a 10-meter section was equipped with either 91 or 153 3D-printed artificial reef elements (0.25m high, 0.40m wide). Data were collected using pressure sensors and flow meters to measure wave transformation, while two ADV arrays analyzed in-canopy flow. These CREST experiments, carried out in collaboration with Plymouth University, Deltares, Boskalis, and Coastruction, contribute to the ARISE project, which explores atoll island adaptation to rising sea levels.

The research addresses four primary objectives: (a) evaluating the impact of artificial reefs on wave transformation, frequency dependence, and water level response; (b) identifying in-canopy flow characteristics; (c) linking these flow characteristics to wave dissipation; and (d) assessing the accuracy of an existing in-canopy flow model.

Findings indicate that as water levels rise, the relative height of the artificial reef decreases, leading to a decline in wave height reduction capacity. The reduction ranges from 8.5% to 15.2% at low water levels and from 4.9% to 5.9% at high water levels. Despite reducing incoming wave heights, artificial reefs can, under certain conditions, increase rather than decrease extreme water levels onshore due to the artificial reef-induced drag force amplifying wave setup.

Analysis of streamwise velocity variance revealed significant spatial differences. Velocity variance decreased more in the ADV array located behind the reef elements compared to the ADV array positioned between them, where velocity variance increased. Flow attenuation was found to be more pronounced at lower water levels, with longer and higher waves attenuated more effectively than shorter and lower waves. The modeled canopy wave dissipation rate, was found to be 43-87% lower than observed dissipation, though still within the same order of magnitude. The discrepancy is partly due to the model not accounting for breaker dissipation and non-linear energy transfers. Flow convergence corrections significantly increased flow attenuation and reduced canopy dissipation rates, while ADV selection had minimal impact.

According to canopy flow regime classification, the tested conditions fell between inertia-dominated and general flow. Reducing element spacing could shift the flow further into the general flow regime, enhancing frequency dependence in flow attenuation and wave dissipation. Given its limited wave height reduction capacity, artificial reefs like these would be most effective when integrated into hybrid coastal protection strategies. Such combinations could enhance both coastal resilience and ecological benefits. Ultimately, the CREST experiments provide a valuable dataset for model calibration and validation, contributing to a deeper understanding of reef hydrodynamics and in-canopy flow dynamics.

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