In many high-tech applications, efficient thermal dissipation is necessary to maintain components within strict operational temperature limits, ensuring system reliability and performance stability. This is achieved mainly through thermal conduction, which is the dominant mechanism between contacting surfaces. Thermal contact conduction is a function of many variables, such as contact area, material properties, and surface roughness characteristics. Various studies have focused on how these variables affect the heat flow between two contacting geometries; however, the inherent variability of the surface roughness induces a significant amount of uncertainty in the measurements. This paper describes the theory and methodology followed to develop a thermo-mechanical framework that incorporates the inherent stochasticity of the surface roughness of metallic surfaces, through a probabilistic surface representation, to efficiently quantify the heat flow conductance through the calculation of the Thermal Contact Conductance (TCC). The results indicate that the proposed methodology predicts the range of thermal contact conductance with good accuracy when compared to experimental data. Lastly, the 2D implementation showed substantially higher computational efficiency compared to the 3D model while retaining comparable predictive capability. ... Read more

Achieving consistent liquid thickness in Liquid Phase Transmission Electron Microscopy (LPTEM) is essential for repeatable, high-resolution imaging. Inconsistencies in chip deformation during clamping can lead to variation in liquid layer thickness and compromise imaging quality. This research develops a simulation–experiment framework to evaluate and minimize deformation in MEMS-based liquid cells, with the goal of improving mechanical repeatability during assembly. The modeling approach begins with 2D finite element simulations to identify critical deformation trends, followed by uncertainty quantification (UQ) and geometry optimization to improve chip flatness. These insights guide full 3D simulations, where the lid geometry is refined to reduce chip deformation and maintain a uniform inter-chip gap near the membrane region. The 50 nm SiNx membrane is decoupled from the main model and studied separately using extracted boundary conditions to reduce computational cost. In parallel, white-light interferometry is used to characterize chip curvature at multiple torque levels using a previous-generation holder. A Gauge Repeatability and Reproducibility (R&R) analysis shows that the experimental method reliably distinguishes deformation trends due to torque variation. Simulation and experiment show qualitative agreement in chip bowing behavior supporting optimization strategy. This work delivers a simulation–experiment workflow for improving mechanical repeatability in MEMS-based LPTEM holders, providing a foundation for future design enhancements and fabrication. ... Read more

As the solar industry continues to grow, the accumulation of photovoltaic (PV) module waste highlights the pressing need for more circular and repairable designs. Conventional laminated modules are difficult to disassemble and recycle, which limits both material recovery and component reuse. While avoiding the lamination improves disassembly, it also compromises the module’s mechanical integrity. This trade-off demands a careful redesign to maintain structural requirements without sacrificing key criteria such as repairability, weight, and cost. This study presents a reliability based optimization approach to redesign the PV module while balancing repairability, weight, and cost constraints. A semi-quantitative relative repairability assessment method, tailored specifically for PV modules, was developed to quantify repairability impacts of design changes. Using Robustimzer software, reliability-base optimization was incoporated to account for uncertain scenarios during the life cycle of the product. Finite Element Analysis and prototype verification ensured compliance with IEC61215 mechanical load standards, achieving an optimized design for mass, repairability and costs simultaneously. As a case study, this methodology was applied to a laminate-free module developed by Biosphere Solar, demonstrating how repairability-focused design can be effectively balanced with structural and economic requirements. The proposed approach offers a scalable framework for advancing sustainable design practices in the PV industry. ... Read more

Climate change is an urgent global challenge. Buildings significantly contribute to energy consumption and CO2 emissions. To accelerate decarbonization, ATES systems, integrated with 5GDHC networks, offer a sustainable approach. These systems enable seasonal thermal energy storage and bidirectional energy exchange. However, designing these complex combined systems in urban areas poses significant challenges, including integrating dispersed ATES wells, managing phased construction, and navigating dense underground infrastructure. This study investigated a biologically inspired approach, utilizing the network optimization capabilities of slime mould (Physarum polycephalum). A simulation model was developed and verified, incorporating key slime mould behaviours like efficient pathfinding, to generate optimal thermal network configurations. Using the TU Delft Campus as a case study, this research explored the model's capacity to streamline the design of sustainable and efficient heat distribution systems. Key findings indicate that the visual differences in layout between the best results and all results are minimal. In conclusion, this research successfully developed and applied a slime mould growth model for optimal thermal network design, specifically for district heating systems combined with ATES in an urban environment. The model proved effective in generating a network designs that minimize CapEx. ... Read more

Hydrofoil crafts with fully submerged foils can provide fast and economical waterway transport. However, their operation requires reliable onboard control systems to ensure the safety and comfort of their passengers, especially in rough sea conditions. This thesis project is focused on the dynamical modelling and the design of motion control systems for an experimental scale hydrofoil craft that is available at TU Delft, namely the Hydrofoil Education and Research Platform (HEARP).

The development of the dynamical model of HEARP is done by taking inspiration from the dynamics of marine crafts and aircraft and relying on different assumptions to obtain a simple and low-order model. The resulting model is a linearized state-space model with three degrees of freedom, namely heave, roll, and pitch, and includes the influence of regular waves. Because of inaccurate available data for the mass properties of HEARP, variations of the system parameters due to nonlinearities, and changes in the operating conditions, different uncertainties are assigned to most system parameters.

The use of multivariable feedback control methods for the motion control of hydrofoil crafts is limited, so this work is focused on exploiting such methods to improve the performance and robustness of such systems. The representation of the perturbed system using real parametric uncertainties is proved to be computationally expensive for the control design. Thus, the perturbed system is approximated by complex (dynamic) perturbations. A signal-based H-infinity optimal controller is designed using the nominal system, and a mu-synthesis optimal robust controller is designed using the approximated perturbed system.

The performance and robustness of the proposed controllers are evaluated in both frequency and time domains through simulations. From the results, it is concluded that both controllers offer high-performance system responses for both reference tracking and disturbance rejection of incident waves. Furthermore, by comparing the two controllers, it is observed that the mu-synthesis controller shows superior robustness for the modelled uncertainty. In contrast, the H-infinity controller has a slightly better performance when considering the perturbed systems with the real parametric uncertainty. The results of this thesis project can be used in the future to experimentally validate the accuracy of the proposed dynamical model and the performance of the designed controllers. ... Read more