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CFD-Driven Optimization of PVC Flocculation and Sedimentation in Industrial Thickener Tank. Enhancing Process Performance and Reducing Environmental Impact Master’s thesis in Sustainable Energy
No full textThe aim of the thesis was to optimize the flocculation process of PVC-particles in a thickener tank to increase the separation of microplastics from the industrial
drain. This was set to be solved by both testing different flocculation concentrations on-site and by simulating the flow dynamics in ANSYS Fluent. A base model of the tank was developed by calibrating CFD data to match laboratory results. This calibrated model was later used to evaluate the effects of flocculant dosage, PVC
inlet concentration and PVC particle size on separation performance. Ultimately, it became clear that particle size was the most critical factor. Fine particles (0.5-1 μm) significantly reduced separation efficiency compared to coarser PVC types (50–250 μm). Additionally, the study identified an optimal PVC inlet concentration (200 mg/L) and flocculant dosage (100 L/h) that minimizes both PVC and flocculant waste
Fuel cell catalyst coating quality for reliable ex-situ ORR activity results
No full textProton exchange membrane fuel cells (PEMFCs) are energy conversion devices that
could play a key role in the reduction of greenhouse gas emissions. However, one
major problem for PEMFCs is the slow oxygen reduction reaction (ORR), which
causes large overpotentials and requires a large amount of expensive platinum catalyst
to be sped up. For that reason, evaluation of the ORR activity of catalysts
is important, and the rotating disk electrode (RDE) method is commonly used for
this purpose. However, there are still problems with achieving reliable results of
the ORR activity with RDE, specifically due to the activity’s dependence on the
quality of the catalyst coating on the electrode. This thesis investigates how different
parameters of a catalyst ink influence the catalyst coating and how to achieve
a uniform thin coating. For one catalyst, inks with different alcohol contents and
platinum loadings were tested, and for a second catalyst, different alcohol contents
and pH levels were tested.
The alcohol content did not appear to have a significant impact on the ORR activity
or the homogeneity of the thin films. A high alcohol content facilitated the spreading
out of the ink due to a lower surface tension, but it was also harder to keep it
from spreading outside the electrode disk. With platinum loading, there seemed to
be a lower limit between 10 and 20 μgPt/cm2 for the catalyst to cover the entire disk
homogenously. Below this limit, the mean specific ORR activity was about 20%
lower. At 34.8 μgPt/cm2, the results were about the same as for 20 μgPt/cm2, meaning
no upper limit appears to have been reached. For the second catalyst, stability
issues were observed, which did not significantly change with the alcohol content.
Increasing the pH of the ink by adding KOH improved ink stability, but it was still
not possible to produce a completely homogeneous coating. Further investigations
on how to achieve a homogeneous coating with this catalyst are therefore needed
A space for grief
No full textThis Master’s Thesis aims to meet the need for
a non-religious space for grief in Gothenburg,
where accessible and neutral venues for secular
mourning ceremonies are currently lacking. It
proposes a project on a dedicated space situated
in Kungsparken, offering individuals a place to
process grief of different kinds, either through
formal ceremonies or personal contemplation, free
from religious connotations. Prioritising social
sustainability, the project aims to provide an
inclusive space for people of all backgrounds.
Drawn on key theories of atmospheric architecture,
such as Böhme’s concept of “ecstasies”, the project
aims to explore how architecture could provide an
allowing space for emotional responses through
aspects like spatial qualities, material properties, and
tectonics. The thesis employs an iterative research
and design process, including prototyping and
testing materials and architectural elements, and
refining spatial configurations based on the findings
surrounding ecstasies. This approach allows for a
dynamic exploration of how various design decisions
impact the overall atmosphere of the space.
Ultimately, the project seeks to create an inclusive,
non-religious space that fills a significant gap in
Gothenburg’s built environment, offering a place for
secular grieving and reflection that is both functional
and emotionally resonant
Navigating the Landscape - Drivers and barriers in Rwanda’s rural electrification and the role of the private off-grid solar sector
No full textMicroscopy for pH mapping in nanofluidic devices
No full textNanotechnology, along with related fields such as nanofluidics, is an area of science with
much potential. Research into material properties at the nano-scale is driving innovation
across various fields, such as the development of new drugs in medicine, and improve ments to solar cells in the development of sustainable energy. This thesis examines the
possibility of creating and measuring pH gradients in nanofluidic channels, as a novel
method to study nanoparticles subjected to different pH environments. The presented
process relies on fluorescence microscopy and a pair of double Amici prisms. When ob serving fluorescent particles or dyes in the nanochannels, the fluorescence is angularly
dispersed by the prisms. This enables measurements that capture spatial distribution of
particles along the nanochannels, and corresponding spectral information dispersed per pendicularly. The experiments confirm that it is possible to generate a pH gradient in
the nanochannels, as well as to move it by applying pressure to the ends on the chan nels. The presented results are largely based on the use of the pH-sensitive fluorescent
dye SNARF-1, and a foundation for future study with nanoparticle FRET probes is also
provided
Drone platform for safety in testing
No full textThis thesis addresses the need for improved safety surveillance in autonomous vehicle testing by developing a drone platform for multiple drones. Extending single drone systems, this work focuses on coordinating multiple drones to provide wider area coverage at testing facilities. The backend of the developed system calculates drone positions based on test trajectories from ATOS, an open-source platform for
automated vehicle testing, ensuring required sensor overlap. Real-time video is streamed from DJI drones via an Android app using Web Real Time Communication to a backend system. The backend processes the streams, performs image stitching to create a panoramic view, and applies object detection with estimated GPS coordinates for bikes, cars, and pedestrians. A web-based frontend allows users to monitor individual and merged video feeds, view detected objects, and control the drones. The system architecture is containerized using Docker. Experimental validations demonstrate the platform’s ability to control drones, stream video in realtime, and provide extended surveillance with object detection. Key challenges and future improvements, including addressing hardware dependencies and automating configuration, are identified. The project represents a collaborative effort between Chalmers University of Technology and Pennsylvania State University
Optimizing a gene panel for enhanced detection of hotspot mutations in endometrial cancer using SiMSen-seq
No full textEndometrial cancer is the sixth most common cancer among women globally, with over 420,000 cases reported in 2022. Current diagnostic techniques lack sufficient specificity or sensitivity, emphasizing the need for new methods to improve early detection and clinical outcomes. One promising approach is analysis of circulating tumor DNA (ctDNA) in liquid biopsies. This project aimed to optimize a gene panel intended for ctDNA-based mutation detection in endometrial cancer using SiMSen-seq, a next generation sequencing method. The project focused on enhancing the performance and coverage of the panel through complementary assay design and incorporation of additional target sites.
We designed and validated six new assays targeting mutations in five of the most frequently mutated genes in endometrial cancer (ARID1A, CHD4, PIK3CA, PIK3R1 and PTEN) for potential incorporation into the panel. Validation was performed primarily using real-time quantitative PCR and automated electrophoresis, and confirmed compatibility of the new assays with the existing multiplexes, with little observed interference. Based on mutation data from the Catalogue of Somatic Mutations in Cancer, a hypothetical detection coverage was calculated. Estimated, the updated panel would detect an additional 2.6% of mutation-positive endometrial tissue samples, increasing the total coverage to 70.4%. Future efforts should focus on validation using sequencing to confirm individual assay performance and diagnostic utility
Conceptual Development of a Standardized Curtain Airbag Interface - With regards to safety, ergonomic assembly and compatibility across vehicle models
No full textCurtain airbags are currently assembled manually onto the car body above the side windows, placing them in an ergonomic red zone for operators. Despite the use of specially designed fixations to facilitate the assembly process, there is no standardized design across Volvo Cars’ vehicle range. Consequently, the attachment points on the curtain airbags and the corresponding hole patterns on the car body vary between models, which is both time and resource inefficient. Therefore, a new curtain airbag fixation design is developed in this thesis, featuring an interface that is optimized for adaptability across a wide range of vehicle models. The development process included benchmarking existing solutions, gathering input from stakeholders and developing conceptual designs and initial prototypes. Key findings from the gathered data indicated that using a screw in the fixation is the most suitable option from a Volvo Cars perspective. Critical requirements that were considered were the need for low push-in forces, traceability and durability during deployment. The proposed solution is a plastic snap-fit ring that fits around the screw. The ring snaps into a hole in the car body and a specially designed weld nut, milled wider at its base, gives space for the ring to secure itself. The final concept achieves the goal of standardization because it
can fit various car models due to its simple footprint, which consists solely of a round hole