Applied Engineering

2026

Attend a PhD defence or find the archive of concluded doctoral research

2026

Attend a PhD defence or find the archive of concluded doctoral research

'Electrochemical CO2 reduction at elevated temperatures' (6/05/2026)

Alana Rossen

Abstract

The rapid rise in atmospheric carbon dioxide CO2 concentrations necessitated by anthropogenic activity requires the development of robust carbon capture and utilization (CCU) technologies. Among these, electrochemical CO2 reduction (CO2RR) offers a promising pathway to synthesize value-added chemicals and fuels using renewable energy. While laboratory research typically occurs at ambient conditions, industrial-scale electrolyzers will inevitably operate at elevated temperatures due to internal ohmic heating. This dissertation investigates the influence of thermal intensification on the performance, stability, and transport phenomena of electrochemical CO2 and carbon monoxide (CO) reduction.One major challenge at 85°C is the morphological degradation of catalysts. To address this, a bismuth-based catalyst integrated with a mesoporous carbon shell was developed. This architecture effectively suppressed bismuth sintering and surface degradation, maintaining high selectivity toward formate for twenty-four hours of continuous operation. Beyond catalyst stability, elevated temperatures exacerbate gas diffusion electrode (GDE) flooding, which disrupts the triple-phase boundary necessary for efficient gas conversion. By implementing precise differential pressure control between the gas and liquid phases, the reaction interface was stabilized, increasing the Faradaic efficiency for formate from 40% to 65% under thermally intensified conditions.The research further transitioned to electrochemical CO reduction within a zero-gap electrolyzer configuration. This architecture circumvents the carbonate salt precipitation issues inherent to CO2 feeds, allowing for a clearer decoupling of thermal effects from bulk electrolyte chemistry. This study revealed that while temperature has a secondary effect on the intrinsic product distribution on copper catalysts, it drastically reduces the crossover of liquid products through the ion-exchange membrane. This reduction in crossover is a critical finding for industrial process design, as it simplifies downstream separation and enhances product recovery.Ultimately, this work demonstrates that elevated temperature operation fundamentally alters the electrochemical environment, influencing parameters ranging from CO2 solubility and local pH to membrane permeability and catalyst longevity. By exploring the interplay between catalyst design, mass transport, and reactor architecture, this dissertation provides a comprehensive framework for the design of next-generation electrolyzers. These insights are essential for the deployment of thermally intensified systems capable of operating at the scales required for global carbon mitigation.

'Geometry- and Topology-Aware Learning for 3D Computer Vision' (1/04/2026)

Stuti Pathak

Abstract

In this defence, we explore how non-Euclidean machine learning can transform raw point clouds into clean, reliable, and high-quality representations for a wide range of engineering domains. In particular, we present novel methods to efficiently simplify large datasets, recover missing information, and reconstruct smooth surfaces from noisy inputs. Together, these contributions bring 3D vision closer to robust and real-time applications in everyday life.

'The NCO Cycle: A Two-step Complete Recycling Process for Polyurethanes' (04/03/2026)

Marthe Nees

Abstract

This thesis investigates new ways to chemically recycle polyurethane (PU), with special attention to the isocyanate-based part of the material, which is often overlooked. While most recycling research focuses on recovering polyols, this work shows that the isocyanate fraction can also be reused effectively in a circular production process.
An improved alcoholysis method was developed to break down PU into carbamates while preventing the formation of unwanted amines. These carbamates were then converted back into valuable isocyanates through thermolysis.
The study also explored process optimization and an alternative application as glue for the mechanical recycling of PU. Overall, the work demonstrates a practical and flexible pathway toward more sustainable and circular PU recycling.

'A Hydrodynamic and Mass Transfer Perspective of Structured Electrodes for Electrochemical Flow Reactors' (05/03/2026)

Michiel De Rop

Abstract

This thesis explores the use of structured 3D electrodes in electrochemical flow reactors to improve performance while keeping energy losses low. In order to quantify this equilibrium, a new evaluation metric, the Hydrodynamic Electrode Performance Factor (HEPF), was introduced. This was needed because conventional electrode designs often focus on maximizing surface area, while neglecting pressure losses that limit overall reactor efficiency and increase operating costs. Through experiments and simulations on pillar-array and 3D-printed TPMS electrodes, the study demonstrates the validity of the newly introduced metric and shows that an engineered electrode design can outperform the surface area alone.

'Describing complexity in the context of plastics recycling: a multi-level statistical entropy lens' (12/02/2026)

Cristina Moyaert

Abstract

This thesis introduces new metrics to evaluate a pressing issue in the transition to plastics circularity; their increasing complexity. At its core, circularity largely deals with managing this complexity, which necessitates its quantification. Using statistical entropy across different levels, i.e. molecular, product and geospatial levels, can support product design and waste management decision-making.

'Towards Application-flexible Embedded Data Acquisition: Framework, Compression and Synchronization' (6/02/2026)

Rens Baeyens

Abstract

Embedded systems play a key role in collecting data from sensors in modern applications. However, existing data-acquisition solutions are often tailored to specific use cases, making them difficult to reuse or adapt.
This dissertation presents a flexible embedded data-acquisition framework that can be applied across different applications. The framework combines modular system design with efficient data compression and accurate time synchronization, enabling reliable and efficient handling of sensor data on resource-constrained devices.
The proposed approach is validated through practical implementations on embedded platforms. The results demonstrate that flexible, scalable, and application-independent data-acquisition systems are achievable, supporting both industrial and research use cases.

‘Bioconversion of Waste Lipids into Long-Chain Dicarboxylic Acids: Process Insights and Optimisation’ (02/02/2026)

Boris Gilis

Abstract

What if we could use yesterday’s cooking oil to replace fossil oil in the production of valuable chemicals? Despite growing sustainability efforts, the chemical industry still relies heavily on fossil resources and energy-intensive production methods. Meanwhile, large amounts of cooking oil and fat wastes are used as a low-value energy source, even though they contain valuable building blocks for chemical production.This PhD research investigated whether waste oils and fats could be converted into long-chain dicarboxylic acids. These acids are versatile components used in materials such as plastics and coatings. Producing these molecules efficiently with conventional chemical processes is challenging. Instead, this research explored a more sustainable approach by using yeasts as tiny biochemical production factories.By developing an optimised and controlled fermentation process, these yeasts converted the waste oils and fats into high amounts of long-chain dicarboxylic acids. This work shows that even complex waste streams can be transformed into valuable products, reducing waste and supporting the transition of the chemical industry towards renewable and circular raw materials.