Chalmers Open Digital Repository

Välkommen till Chalmers öppna digitala arkiv!

Här hittar du:

  • Studentarbeten utgivna på lärosätet, såväl kandidatarbeten som examensarbeten på grund- och masternivå
  • Digitala specialsamlingar, som t ex Chalmers modellkammare
  • Utvalda projektrapporter

Enheter i Chalmers ODR

Välj en enhet för att se alla samlingar.

Senast inlagda

Minimize the aerodynamic effect of a strut on the wing
(2023) Santor Blair, Andres Felipe; Utku, Mert; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Chalmers University of Technology / Department of Mechanics and Maritime Sciences; Xisto, Carlos; Antunes, Alexandre
The field of aircraft design is continuously advancing through the utilization of scientific techniques and empirical methods. The incorporation of computational methods has facilitated the design process of new and complex aircraft, enabling more efficient conceptual design and optimization. These advancements have the potential to significantly reduce fuel consumption and emissions, making a positive impact on the environment, a critical global concern. The development of battery-electric airplanes represents a significant step towards creating a more sustainable aviation sector. Among the various emerging concepts, the Strut-Braced Wing (SBW) has shown great promise in enhancing aerodynamic efficiency while reducing wing weight. However, the implementation of new concepts and technologies also presents new challenges and limitations that must be addressed, particularly the impact of aerodynamics on the aircraft’s range, which can impose limitations on its maximum travel distance. The primary objective of this thesis is to minimize the aerodynamiceffects of a strut and wing configuration by reducing total drag and increasing the Oswald efficiency of the Strut-Braced Wing during the conceptual design phase. To achieve this goal, Sequential Quadratic Programming (SQP) and Genetic Algorithm (GA) optimization algorithms are employed, utilizing low-fidelity Computational Fluid Dynamics (CFD) methods. The airfoil data utilized in the study is obtained from the XFOIL tool, which provides important viscous aerodynamic characteristics. By implementing these methodologies, it is anticipated that the aerodynamic performance of the Strut-Braced Wing configuration can be optimized, leading to improved efficiency and weight reduction. The results obtained from this research will contribute to the advancement of aircraft design and promote the development of more environmentally friendly and efficient aircraft during the conceptual design phase.
Dynamic Material Flow Analysis for Battery Cell Circularity in Mining Equipment
(2023) Ekblad, Johanna; Viberud, Lydia; Chalmers tekniska högskola / Institutionen för teknikens ekonomi och organisation; Chalmers University of Technology / Department of Technology Management and Economics; Arvidsson, Rickard; Helander, Harald
Over the last decade, electric vehicles (EVs) have advanced considerably, with predictions of continued rapid growth. However, the batteries driving this electrification contain rare materials like lithium, nickel, and graphite, which are expected to face increased demand. This surge in demand poses challenges related to material supply and resource constraints. Circular economy principles can reduce the constraints and extending battery life through reuse and recycling loops. The mining industry exemplifies this transition, substituting diesel-powered equipment with electric alternatives in mines. This study therefore aims to investigate the resource implications of increased circularity for battery cells in mining equipment until 2050. Specific objectives include developing a dynamic material flow analysis (dMFA) model, examining effects under different reuse scenarios, and analyzing recycling rate implications. Results from the dMFA model show that life extension practices, such as reuse in other machines and battery energy storage solutions (BESS), can considerably reduce the demand for primary materials when electrifying the mining sector. For example, life extension possibilities in other mining equipment could in 2050 result in a lower demand for primary material, corresponding to a reduction of 17%. In the other scenarios, this level of reduction is affected by collection rate, recycling rate and the possibility of reusing batteries in BESS. However, practical challenges in infrastructure and compatibility arise with increased battery cell flows. The results further underscore the challenges arising from mining electrification, including infrastructure overhaul, longevity of operational mines, and practical issues in battery reuse. The thesis highlights the role of legislation in advancing recycling and technological adoption, emphasizing the need for clear legal frameworks. Collection rate mandates and product-service systems can incentivize businesses to enhance recycling efforts. Despite uncertainties in the dMFA model, the findings offer guidance for stakeholders and policymakers in enhancing sustainability within the mining sector. Future research is suggested to delve into the feasibility of life extension strategies and conduct life cycle assessments to investigate environmental impacts of electrifying mining equipment.
Development of analytical and sensitive methods to detect and quantify therapeutic oligonucleotides
(2023) Domagala, Izabela; Chalmers tekniska högskola / Institutionen för life sciences; Chalmers University of Technology / Department of Life Sciences; Wenzel, Michaela; Ståhlberg, Anders
Therapeutic antisense oligonucleotides (ASOs) had a breakthrough in 1998 when fomivirsen, an inhibitor of human cytomegalovirus, was approved for medical use. Scientists discovered the medical potential of therapeutic oligonucleotides in treatments of various conditions and diseases, leading to the research field gaining more popularity. A challenge within this research field is the detection and evaluation of different oligonucleotide sequences, as no established quantitative and sensitive methodologies are present for these. The aim of this thesis is to develop analytical and sensitive methods for detection and quantification of therapeutic oligonucleotides. Particularly antisense oligonucleotides (ASOs), for application in in vitro experiments associated with fields such as cancer research. The ASOs included in this project are EBER1-5 and EBER1-6. The two-tailed RT-qPCR method, used for detection of miRNA, was adapted and modified in this project. The method was changed so that instead of a reverse transciption, a PCR was performed to anneal and elongate the two-tailed primer with the ASO. The PCR was then followed by a qPCR analysis. Different deviations to the initial protocol as well as to the designs of the primers and oligonucleotides, were performed during the project. The results showed that the method is promising as detection was possible to approximately 105 molecules, which corresponds to a concentration of 83 fM. Still, improvements need to be done for the binding and the elongation in the two-tailed part of the method to be able to reliably detect lower amount of molecules.
The design and usability of an eHealth demonstrator aimed to facilitate the prevention and care of persons with diabetes at risk to develop diabetic foot ulcers
(2023) Ravichandran, Shivani; Chalmers tekniska högskola / Institutionen för elektroteknik; Candefjord, Stefan
Design And Analysis Of Wireless Power Transfer Using High Frequency Resonant Inductive Coupling By Changing The Coil Geometry
(2024) Gouthamas, Nagendra; Bandi, Adarsh; Chalmers tekniska högskola / Institutionen för elektroteknik; Thiringer, Torbjörn; Thiringer, Torbjörn; Larsson, Fredrik
Abstract In this thesis, we have developed a wireless power transfer system for a space of dimensions (15cm x 15cm x 15cm), utilizing a series-connected transmitter (Tx) coil to generate an equally distributed electromagnetic field inside the space. This field can be picked up by a solenoid receiver (Rx) coil placed anywhere within the space to power a DC load. To develop the proposed system, we have studied a conventional wireless power transfer system fromWurth Electronics and investigated various coil geometries for both Tx and Rx. The conventional wireless power system has been examined regarding the influence of coil geometry, alignment between the transmitter (Tx) and receiver (Rx), as well as the coil parameters on efficiency. The wireless power system from Wurth Electronics is tested with different Rx coil geometries to evaluate interoperability between various Tx and Rx coil geometries, as well as to compare the coupling coefficient and magnetic field density of different Rx coil geometries with misalignment in order to evaluate most suitable Rx coil geometry for the proposed wireless power system. The different Rx coil geometries investigated are: concentric, solenoid, and center-tapped circular coil. The comparison is based on different alignment conditions between the transmitter and receiver coils. We find, from the results obtained by investigating different Rx coil geometries with the conventional system, that the solenoid coil geometry with a core provides a stable coupling coefficient under various misalignment conditions. Thus, the solenoid Rx geometry can be optimized to enhance coupling between the transmitter and receiver coils. Additionally, test results show that the use of center-tapped circular coils in wireless power power system helps in improving range from 30mm to 180mm compared to conventional wireless power system with concentric coils. However, the improved range is only achievable with significantly higher number of coil turns compared to concentric coils which reduces efficiency. Also, a unique BJT based automatically switching transmitter circuit is required for the center-tapped circular coils which makes it a non-viable solution due to inefficiency of the BJTs. Further a suitable transmitter coil geometry is investigated for use in combination with the solenoid receiver to demonstrate the proposed wireless power system within a space of dimensions (15 cm x 15 cm x 15 cm). Three different transmitter coils are investigated: the concentric coil, 2-series connected concentric coil, and 8-series connected concentric coil. A half-bridge transmitter circuit is designed to drive the various transmitter coils. The experimental and simulation results indicate that the concentric transmitter coil with a large diameter enhances high power transfer and better range due to a more effective distribution of the magnetic field. However, when using a solenoid receiver coil, the power transfer efficiency drops by 28% compared to the efficiency of 75% under aligned operation. Consequently, the concentric transmitter coil is designed with the coil turns distributed into smaller areas, forming a 2-series connected coil. Test results reveal that it was possible to transfer 10W of power at an efficiency of 75% when the coils were perfectly aligned. In contrast, when the coils were misaligned, power transfer efficiency of up to 48% was achieved. This is in contrast to the power transfer efficiency of 6% under misaligned conditions in the conventional wireless power system. The 2-series connected concentric Tx coil is then extended to an 8-series connected concentric Tx coil to form a space of dimensions (15 cm x 15 cm x 15 cm) in combination with a solenoid Rx coil. Simulation results indicate that the coupling coefficient between Tx & Rx improved by approximately 11% and measurement results show that power transfer efficiency improved by 4% compared to the 2-series connected concentric Tx coil. Similarly, when the solenoid Rx coil was rotated or misaligned with the Tx coil, the efficiency improved by approximately 33% compared to the 2-series connected concentric Tx coil. The increase in efficiency and coupling with Tx and Rx is mainly due to distribution of coil turns into smaller areas and then connecting them in series which improved the magnetic field distribution compared to other coil geometries. Hence, the 8-series connected concentric coil as Tx and solenoid as Rx are selected as the suitable Tx and Rx coils, respectively, for the proposed wireless power system. In comparison to the conventional wireless power system, the efficiency remains approximately the same at 80% when the coils were perfectly aligned and efficiency improved by more than 60% when the coils were misaligned.