Chalmers Open Digital Repository

Welcome to Chalmers Open Digital Repository!

Here you can find:

Student theses and papers
Digital special collections, such as Chalmers modellkammare
Selected project reports

Research publications, reports and dissertations can be found in research.chalmers.se

Communities in Chalmers ODR

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Now showing 1 - 2 of 2

Recent Submissions

A Lattice Gas Cellular Automaton with Tomographic Dynamics
(2026) Lunman, Sackarias
We study the tomographic effect in lattice gas cellular automata, which are simple discrete models for hydrodynamics. The tomographic effect is predicted in two-dimensional Fermi liquids whenever head-on scattering dominates, leading to inefficient angular relaxation due to Pauli blocking. As a result, odd-parity deformations of the Fermi surface are anomalously long-lived compared to even-parity ones. We find an analogous effect in two-dimensional triangular lattice gas automata, which exhibit a single discrete odd-parity mode that we call the hexapolar mode. We analyze the relaxation times of the linearized lattice gas dynamics, and find that at low densities, head-on collisions dominate and the odd-parity mode is long-lived, resulting in a two-step relaxation of the system. At higher densities, three-body interactions set the dominant decay channel and the odd-parity mode becomes short-lived. We then analyze a reduced model of the lattice gas with a long-lived hexapolar mode, and derive the equilibrium distribution via entropy maximization. Using a small perturbation approximation and a multi-scale expansion, we derive a set of macroscopic equations that incorporate the hexapolar mode. We show that the odd-parity mode couples anisotropically to the momentum, leading to direction-dependent dynamics. We analyze the linear hydrodynamic modes and solve for the velocity profile in a channel (Poiseuille flow). We then compare our findings with the expected behavior for a two-dimensional Fermi liquid that exhibits the tomographic effect. Using the linearized kinetic equation for a two-dimensional homogeneous electron gas, we derive a set of linearized macroscopic equations. We conclude by discussing the limitations of the model due to its discrete nature and lack of full rotational symmetry.
Optimizing Foam Construction for Seat Comfort - An Investigation into how the Shaping and Layering of Foams with Different Hardness Affects Seat Comfort
(2026) Alveheim, Hannes; Fermskog, Sebastian
The gaming chair market has long been dominated by maximalist aesthetics and designs inspired by motorsport without prioritising comfort. This thesis, conducted in collaboration with Fractal Design, investigates how varying the cushion hardness across the seating area can be used to optimise seat cushion comfort for gaming chairs. Through a pre-study comprising of a literature review, patent research, competitor analysis, user studies, and expert interviews, a user needs list was established to guide the design process. Furthermore, the competitor analysis found that gaming chair aesthetics are highly flexible, allowing seat cushion geometry and material selection to be optimised for comfort without compromising market relevance. Two iterative design phases followed. In the first, 12 concepts were generated and evaluated using a Kesselring matrix and user tests on low-fidelity prototypes, leading to the selection and subsequent manufacturing of three higher-fidelity prototypes. In the second iteration, the two best performing concepts were combined into a final design, a two-part foam cushion with an engineered mating surface that effectively varies foam hardness across the seat interface. Three final prototypes with identical average densities, but different hardness ratios between their top and bottom halves, were manufactured using 3D-printed moulds and evaluated by 15 participants. The results demonstrate that a horizontally layered foam construction, with a softer upper layer and a harder lower layer, outperforms a homogeneous foam of equivalent average density in, terms of perceived comfort, by changing its pressure distribution properties. The concept with a 17% denser bottom layer ranked highest in comfort and was perceived as the softest, suggesting that engineered foam constructions can create a more comfortable seating experience, simultaneously providing a soft initial sensation and adequate structural support.
Förbättring av löparväska - Baserat på användarstudie i samarbete med Kilometer Studios
(2025) Alström, Josefin; Simic, Jefimija
Kilometer Studios, previously known as IAMRUNBOX, is a company specializing in designing backpacks made for physically active commuting. The most popular backpacks in the product line are the Backpack Pro and Spinbag 30L. The Backpack Pro is specially designed with run commuters in mind while Spinbag 30L is designed with bike commuters in mind. With an additional product, the Spinbag 30L can be adaptable for run commuting as well. This project investigates and evaluates run and bike commuters needs and requirements on the backpacks. Divided into two parts, the project covers both user research and product development. In the researchin part, users’ opinions were explored by interviewing and researching relevant parties. The product development part was founded on the researching phase of the project. While brainstorming and designing ideas, various factors such as functionality, ergonomics, safety and sustainability were taken into account. By using various methods to evaluate the different ideas, two final concepts were conducted.
TURITZTEATERN
(2026) Backlund, Alice
Development of a Non-Invasive Blood Pressure Measurement Device for Cardiopulmonary Exercise Testing
(2026) Heed, Anna; Petersson, Julia
In this thesis the conceptual development and prototyping of a non-invasive blood pressure (NIBP) measurement device intended for use during cardiopulmonary exercise testing (CPET) at Sahlgrenska University Hospital (SU) is presented. Reliable blood pressure (BP) monitoring during exercise is essential for both patient safety and clinical decision making, but existing methods are challenged by limited usability and reliance on outdated equipment. The aim of the project was to identify clinical and regulatory requirements, develop a conceptual design and prototype solution. This while simultaneously initiating technical documentation in accordance with the Medical Device Regulation (MDR). The project included literature studies, interviews with healthcare professionals, regulatory analysis and iterative prototyping. User and product requirements were established based on clinical needs and relevant standards. Four prototype iterations were developed and evaluated with respect to controllability, inflation and deflation performance, leakage and usability. The results demonstrated that a mechanically controlled system using hospital compressed air can provide rapid and controllable cuff inflation and deflation suitable for CPET environments. Clinical feedback highlighted the importance of usability and compatibility with existing workflows. The project also identified key regulatory considerations related to in-house manufacturing under the MDR. In conclusion, the study demonstrates the feasibility of developing an in-house NIBP device adapted for CPET and provides a foundation for further technical development and future clinical evaluation.