Examensarbeten för masterexamen

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    Studying Interactions of Complex Lipid Vesicles with Cell Membrane Mimics
    (2024) Kosta, Eleftheria; Chalmers tekniska högskola / Institutionen för fysik; Chalmers University of Technology / Department of Physics; Höök, Fredrik; Holme, Margaret
  • Post
    Indirect Nanoplasmonic Hydrogen Sensing
    (2024) Albert, Rémi; Chalmers tekniska högskola / Institutionen för fysik; Chalmers University of Technology / Department of Physics; Langhammer, Christoph; Theodoridis, Athanasios
    The critical role of hydrogen in the global energy transition and its hazardous na ture underscores the importance of developing efficient and reliable hydrogen sensing technologies. This thesis explores the advancement of a hydrogen sensing method using indirect Localized Surface Plasmon Resonance (LSPR), where we investigate the alloying properties of small metal nanoparticles by means of solid-state dewet ting. The results from this thesis project are divided into three key parts. (i) A proof-of-concept has been realized, showing that indirect LSPR can be used as a means of monitoring hydrogen concentrations, using Ag 140x20nm nanodisks cov ered with much smaller (few nanometers) hydride-forming P d nanoparticles. (ii) Building on the insights gathered from the previous part, alloying of P dAu through solid-state dewetting has been investigated to replace the P d nanoparticles, yielding more than a twofold increase in performance with comparison to (i) and 10 times faster kinetics than its bulk equivalent (i.e. P dAu in direct LSPR). And finally (iii), an attempt to make all depositions through the mask, which proved to be unsuc cessful and suggests using a hard sacrificial mask instead of the soft PMMA-based one used in this work. Overall, this thesis highlights the promising potential of indirect LSPR for hydrogen sensing, offering a foundation for future research and technological development in this field.
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    Improvement of decal transfer method for preparing fast and reliable CCM assembly
    (2024) Hurtig, Adam; Chalmers tekniska högskola / Institutionen för fysik; Chalmers University of Technology / Department of Physics; Wickman, Björn; Mikaeili, Parinaz
    As sustainable energy solutions have garnered more importance in society and to governmental bodies, a technology getting attention as being part of the solution and a step in the right direction is the proton exchange membrane fuel cell (PEMFC). This comes as the PEMFC uses hydrogen and oxygen to create electricity, with the side-products being heat and water, which means that it is a very clean energy converter. At the heart of the fuel cell is the catalyst coated membrane (CCM), which is where the reactions take place, and it is the component investigated in this thesis. Although there are multiple ways of fabricating CCMs, the method used in this thesis is the decal transfer method. Using this method, parameters such as temperature and pressure were varied to investigate the optimal parameters under different conditions. These conditions included the usage of different membranes, three different cathode loadings and two CCM areas. During this process, several analytical tools were employed, with the intent of finding the most effective quality check method for in-house production of CCMs. This included the usage of an optical microscope, lightboard and high intensity light. The performance of CCMs assembled using optimized parameters was also examined by in-situ fuel cell testing. Lastly, an investigation into the most appropriate pressure pad material was performed. The results in this thesis outlines the optimal parameters for each condition and proposes both the most effective quality check method and the most suitable pressure pad material.
  • Post
    Sensitivities of the runaway current in JET disruptions to massive gas injection and initial plasma current
    (2024) Gustavsson, Christian; Chalmers tekniska högskola / Institutionen för fysik; Chalmers University of Technology / Department of Physics; Pusztai, István; Hoppe, Mathias; Ekmark, Ida
    The Joint European Torus (JET) tokamak, located at the Culham Centre for Fusion Energy in the UK, has been a leader in magnetic confinement fusion (MCF) research for decades. As the world’s largest operational tokamak until 2023, JET has sig nificantly advanced the understanding and technology needed for controlled fusion energy, which aims to provide a clean, large-scale energy source by replicating the processes that power the Sun. A primary challenge in tokamak operation is man aging plasma disruptions, which can terminate plasma confinement and generate runaway electrons (REs). These high-energy electrons can damage reactor compo nents, thus studying REs is vital for the viability of fusion energy. As the fusion community progresses towards advanced reactors like ITER in France and SPARC in the USA, understanding and controlling REs becomes even more important. This study uses the Disruption Runaway Electron Analysis Model (DREAM) to investigate the conditions under which REs form during tokamak disruptions. The main objective of this thesis is to model the conditions for the existence of REs in JET massive gas injection (MGI) discharges, focusing on their dependence on magnetic field strength, initial plasma current, as well as the ratio of injected argon to deuterium. Furthermore, we are interested in how much current is carried by the REs after a disruption. The analysis is conducted through a series of parameter scans using the simulation tool DREAM. Our simulation results show that the RE current is influenced by the initial plasma current and the ratio of injected argon to deuterium, with only a very weak dependence on magnetic field strength. More over, our findings suggest that the injection profile of argon significantly affects the parametric trends of the maximum RE current. A uniform injection profile yields an inverted current trend compared to an edge-peaked injection profile, where the latter yields results that are more in line with experimental results.
  • Post
    Tissue Engineered Artificial Urethra: 3D bioprinting platform design and bioink development for tubular structures
    (2024) Odbratt, Johanna; Öjmertz, Matilda; Chalmers tekniska högskola / Institutionen för fysik; Chalmers University of Technology / Department of Physics