Browsar Studentarbeten // Student Theses efter Titel
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- Post1,2,3-Triazole-based Synthetic Receptors for Biosensor Applications(2022) Farhan Ahmed, Abdinasir; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Mårtensson, Jerker; Kann, Nina
- Post12.273799 E 63.042831 N - Structural and contextual wooden design in a parametric environment(2013) Nordström, Lukas; Chalmers tekniska högskola / Institutionen för arkitektur; Chalmers University of Technology / Department of Architecture
- Post1820 - Med konserter som innehåller oväntade inslag(2023) Hu, Bingjie; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers University of Technology / Department of Architecture and Civil Engineering (ACE); Olsson, Karl-Gunnar; Christensson, Peter; Lund, Morten
- Post1:1 - exploring temporary urban spaces as an architectural tool(2011) Börjesson, Mia; Chalmers tekniska högskola / Institutionen för arkitektur; Chalmers University of Technology / Department of Architecture
- Post1D Edge Contacts to 2D Material Heterostructures(2021) Karpiak, Bogdan; Chalmers tekniska högskola / Institutionen för mikroteknologi och nanovetenskap (MC2); Zhao Ternehäll, Huan; Prasad Dash, SarojGraphene has been in the focus of research in many fields of applications due to its unique properties. In particular, the 2D nature, low charge carrier concentration and high mobility of carriers are promising properties for the use in magnetic Hall sensors. At the same time, low spin-orbit coupling and negligible hyperfine interactions make it interesting for spin-polarized electron transport. However, single graphene layer, if unprotected, is prone to defects introduced during fabrication processes and also defects due to interfaces with other insulators or contact materials. These factors would inevitably lead to decrease of graphene device performance. By encapsulating graphene in hexagonal boron nitride (h-BN), another insulating atomically flat twodimensional (2D) material with superior interface properties with graphene, one can fabricate heterostructures for robust and high-performance devices. Utilizing one-dimensional (1D) edge contacts to graphene sheet in such devices based on 2D materials would also allow to minimize contacts-induced degradation of channel properties. The graphene/h-BN heterostructures for studied devices were prepared both by exfoliation from bulk crystals and by transfer of CVD-grown materials over large area. After patterning the 2D heterostructures, 1D edge contacts were fabricated by means of electron or laser beam lithography and electron beam evaporation of metals. In these devices, proof-of-concept for batch fabrication of Hall elements on large area all-CVD h-BN/graphene/h-BN heterostructures is demonstrated. Such 1D edge contacts of ferromagnetic materials to graphene/h-BN heterostructures are also explored for spin injection into graphene in devices with novel design. The findings described in this thesis allow to advance the graphene Hall elements fabrication technology towards large-scale, industry-compatible manufacturing and lay basis for understanding and further optimization of the phenomena that drive and influence the operation of graphene spin-based devices with novel design involving 1D edge contacts.
- Post1D model development and simulation of low-grade waste heat recovery from a marine engine(2021) Bhandari, Varun; Chalmers tekniska högskola / Institutionen för rymd-, geo- och miljövetenskap; Papadokonstantakis, Stavros; Papadokonstantakis, Stavros; Galuppo, FrancescoThe increasing awareness about the effect of emission of CO2 into the atmosphere, as well as meeting the emission targets set by IMO (International Marine Orga- nization) by 2050 results in a continuous need for improving efficiencies of marine engines. A large portion of the fuel's chemical energy is lost to the surroundings as heat, even in the most energy efficient engines. Waste heat recovery through a rankine cycle has emerged as a promising way to increasing the engine efficiency by utilizing the untapped availability of waste heat in the coolant systems as well as the exhaust of the engine. The highly transient nature of operation of an engine and depicting the heat transfer phenomenon in an ORC (Organic Rankine Cycle) accurately makes the represen- tation of an ORC through a mathematical model quite challenging. Based on the application, selection of the right working uid, equipment and control strategy is crucial for the performance of the ORC In this thesis, a Simulink based mathematical model of an ORC for waste heat recov- ery from a marine engine is built. The WHR (Waste Heat Recovery) model is built for transient operation. The model is run on a road cycle, built from actual field test data of a boat, to simulate its performance in actual operation of the marine vessel. Further, the performance of ORC with di erent working uids and different type of expanders is evaluated. And finally, a rough cost estimation of the ORC is done. The results from the project show that the refrigerant R1234ze(Z) is the most suit- able for engine coolant WHR application and turbine expander performs better than the volumetric expander. Lastly, as the scale of the ORC system increases, it becomes increasingly cost effective.
- Post1D Modeling and Simulations of Soot Oxidation in Diesel Particulate Filters and Monoliths using GT-POWER(2016) Lerdmaleewong, Chanin; Luong, Staffan; Chalmers tekniska högskola / Institutionen för tillämpad mekanik; Chalmers University of Technology / Department of Applied MechanicsDiesel particulate filter (DPF) is part of the exhaust aftertreatment system for diesel engines. The DPF’s main function is to trap particulate matter (soot) from the exhaust stream. The trapped soot is removed by regeneration of the filter. The regeneration process involves soot oxidation via oxygen and nitrogen dioxide. Simulations on kinetics and pressure drop are widely used in the assessment of the DPF. In this work detailed kinetic models of soot oxidation (by oxygen) were investigated and implemented in a flow-through monolith model and also in a DPF model using GT-POWER. The detailed kinetic models and data origins from previously published data. The DPF model consists of a number of interrelated sub-models soot oxidation by NO2 , NO oxidation and pressure drop. These sub-models were developed by using semi-steady state and transient engine data on a catalyzed DPF. Kinetics and pressure drop analysis were found to be the key in finding parameters for the models. The implementation of these models into GT-POWER required some special techniques due to rigid built-in model structure. The detailed kinetics was adequate to predict the low temperature experiment, in general, the detailed kinetic model was able to reduce the residual by approximately 25% compared to global kinetics model.
- Post1D Modelling of Fuel Mixing and(2013) Gustaf, Lindberg; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and EnvironmentA one-dimensional model for fuel mixing and conversion in a bubbling fluidized bed has been developed. The model includes fuel particle size development and calculates the concentration profile for char, volatiles, moisture and ash as well as the fuel particle size distribution. Three different kinds of units have been modelled: gasification, combustion and chemical-looping combustion. Two types of fuels, wood and coal, have been used. Based on the results from the model, the addition of a fragmentation sub-model is very important to fully characterize the char composition in the outlet and the inclusion of particle size classes and particle size development has a large effect on the result. The model presents convergence problems for certain combinations of inputs, such as combustion of fragmenting wood. The model results are sensitive to the value of many inputs such as fuel specific parameters regarding fragmentation and reaction kinetics. Because of these inputs, the use of the model for non-characterized fuels can only be of more qualitative than quantitative use.
- Post1D Simulation Modeling for an Exhaust Aftertreatment System SCR Calibration Modeling in GT-SUITE(2021) Ramanjaneyalu, Puneeth; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Sjöblom, Jonas; Sjöblom, Jonas; Yitbarek, ZemichaelThe Euro legislative regulations are imposed successively to hold back toxic elements that are harmful to the environment. Carbon monoxide (CO), hydrocarbons (HC) and nitric oxide (NOx) are the major toxic elements that cause serious health hazards for the living species. From many research works, selective catalytic reduction (SCR) is the most promising technology to address NOx. The objective of this project is to develop a surface reaction mechanism model, reaction rate calibration for SCR catalyst and validation. Firstly, building the SCR catalyst and surface reaction mechanism model in GTSUITE. The reaction rate calibration or characterization is performed for six reaction rate expressions with 18 unknown parameters by applying physical properties of the catalyst for example diameter and area of the catalyst. Furthermore, the digital laboratory Simulink black-box is utilized to produce the target reaction rate curves for all chemical reactions to calibrate the parameters then to compare with simulated GT-model results. Finally, validation for steady state or urea stairs, US, conditions and transient driving cycle conditions against WHTC (world harmonized transient driving cycles) for the Euro V regulations using tail pipe, engine-out emissions, mass flow rate and temperature traces experiments data. Overall, chemical kinetics modeling for SCR catalyst in GT-SUITE was successfully implemented and have reasonable results for urea stair cases, but the outcome can be further improved for transient cycles by extract information from 3D CFD to 1D in the future. Inevitably, simulations analysis is the best possible way to validate the results in quick time with low cost and it is a key factor during the development process.
- Post1D Transient Simulation of Heavy Duty Truck Cooling system – HDEP 16 DST, Euro 6(2012) Raghavan, Ganesh; Chalmers tekniska högskola / Institutionen för tillämpad mekanik; Chalmers University of Technology / Department of Applied MechanicsIn future and also in the present time, with the focus on minimizing environmental impacts, the truck industry faces a big technological challenge in terms of meeting statutory emission legislations and also on satisfying the ever increasing demand of customers in terms of minimizing the fuel consumption. There are other challenges in terms of having a short development time and reducing the overall development cost. All the above stated challenges requires measures in terms of how computer simulations can be used to better represent a system, how different concepts can be tested, how the overall system can be tested in particular system working environment which ultimately will give a short development time with minimum cost. This thesis work basically answers the above questions in a holistic manner by considering how the truck cooling system be modeled using different CFD tools like AMESim and GT Cool to understand how different performance parameters of a cooling system vary for a steady and transient driving cycle. In this thesis work, the cooling system model has been developed for an ongoing project in Volvo Powertrain AB. The model has been developed for 16L DST, 750 Hp, Euro 6 heavy duty truck engine with other auxiliary components like, air compressor, transmission oil cooler, cab heater, urea heater to mention a few. The model has been developed such that it can run on both steady and transient cycles by changing few elements in terms of how the input is given to the model. One of the aims of this thesis work was to evaluate the two tools mentioned above in terms of workability, implementability and reliability. Results in terms of pressure drop, mass flow rate, heat transfer rate, thermostat valve fluctuation etc. have been compared for above mentioned tools. It is pointed out that since the model has been developed for an ongoing project, the validation of the model by performing actual tests couldn’t be performed because of the unavailability of the engine. In the end certain conclusions have been drawn out in terms of cooling system performance and how effective the tools were in simulating the cooling system.
- Post2 x F(ACADE) Properties and guidelines for double-skin facades in Sweden(2014) Koukaroudis, Panagiotis; Chalmers tekniska högskola / Institutionen för arkitektur; Chalmers University of Technology / Department of Architecture
- Post20 kW pulslastnätdel - topologival och genomförande(2008) Vinnberg, Andreas; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and EnvironmentDenna rapport visar på skillnaderna mellan både topologival på hög abtraktionsnivå, huvudsakligen energilagring och medel- eller peakenergiöverförning som på låg abstraktionsnivå såsom switchtopologi (flyback, halvbrygga, fullbrygga och så vidare) och likriktning för ett fall med hög lastvariation och algebraiska uttryck formuleras för val av desamma. Funktioner för kondensator- och transistoregenskaper i förhållande till deras pris beräknas och val av optimala kondensator- och transistorval diskuteras. En prototyp byggdes för att verifiera resultaten. För en DC/DC-omvandlare som matas från en PFC med 20 kW medeleffekt under pulslast föreslås en peakeffektomvandlare bestående av två fullbryggor, fasskiftade 180 grader ur fas som har i princip all energilagring på primärsidan.
- Post25 kvadratmeter liv - ett sökande efter ljus och skuggor i små byggnader(2014) Radeklev, Therése; Chalmers tekniska högskola / Institutionen för arkitektur; Chalmers University of Technology / Department of Architecture
- Post2D Finger Motion Tracking, Implementation for Android Based Smartphones(2012) Khosravi Nahouji, Maryam; Chalmers tekniska högskola / Institutionen för data- och informationsteknik (Chalmers); Chalmers University of Technology / Department of Computer Science and Engineering (Chalmers)Human computer interaction grows day by day and nowadays it has been entered many aspects of the life. Through this growth it has covered not only the desktop and laptop PCs but also mobile phones and specifically Smartphones. Therefore it worth to consider this topic and try to make a new functionality for these kinds of interactions. The intention is to find a practical way to make a new use of the video camera of the Android based Smartphones and track a single finger using the camera as sensor. To track an object in Android platform it needs some special prerequisite. It means that there should be a way to make the tracking applicable on Smartphones. for this purpose the solution this work has come up with is to use OpenCV library which is an open source library specialized for computer vision applications. This library is applicable on Android platform and therefore can be considered for our intention. Also considering different methods applied for hand tracking purpose in earlier works which has been studied in this work, the intention was to implement a method which was not been used by later studied works. Therefore the method of tracking used in this work is called “Motion Templates”. This method is a method represented by OpenCV library and used in this work. To reduce the complexity of the work the first mile-stone which is implemented in this work is to track the finger on PC and then try to port the method and algorithm to Android platform. The tracking is done successfully on the PC using this method and it can be recommended as a possible way of tracking to be considered on Android platforms as a future work.
- Post2D visionbaserad positionsbestämning Precision hos visionsystem(2012) Anderung, Max; Chalmers tekniska högskola / Institutionen för data- och informationsteknik (Chalmers); Chalmers University of Technology / Department of Computer Science and Engineering (Chalmers)Vissa applikationer kräver att positionen på detaljer som skall bearbetas kan bestämmas och bakgrunden till detta projekt är att kunden tidigare fixerat skär1, som skall bearbetas, med hjälp av en fixtur. Fixturen utsätts då för mekanisk nötning vilket till slut påverkar positioneringen av detaljen. Genom att använda sig av ett visionsystem kan förhoppningsvis detta problem elimineras och en problemfri repeterbarhet erhållas. Vision i detta sammanhang innebär bildbehandling med en speciell mjukvara för att extrahera viss information ur en bild som sedan kan användas som olika typer av reglerparametrar. I projektet har mjukvaran Halcon använts. Halcon är specialiserad för att extrahera information ur bilder som sedan kan användas i en mängd tillämpningar. Mätningen kommer att kantas av störningar och det ingår således i uppgiften att undersöka effekten av dessa. Problemet har lösts genom mjukvaruutveckling samt design av mättester som skall simulera den varierande miljön som råder i olika fabriker. Den störningen som anses vara svårast att behandla och därför viktigaste störningen är smuts. Denna störning resulterade i ett mätfel på ca 5 % av en pixel och en kräver en scenstorlek med bredden 25-30mm.
- Post3-D computations of eddy current losses in core ends of salient-pole synchronous machines(2004) Chitroju, Rathna; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and Environment
- Post3-D object tracking through the use of a single camera and the motion of a driverless car(2021) Ovnell, Andreas; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Benderius, Ola; Benderius, OlaThere has been a very large increase in interest and development of partially or fully driverless cars in recent years. For these driverless cars to function, they need to be able to navigate to their destination while avoiding nearby objects. This can be done using simultaneous localisation and mapping (SLAM). SLAM is the task of simultaneously creating a map of the surrounding objects while keeping track of the car’s position within this map. This thesis will look into the feasibility of using a single camera attached on a driverless car to perform SLAM on cones detected by the real-time object detection system You only look once (YOLO). Three different methods were tested. All of these require a calibrated camera that is capable of determining horizontal and vertical angles from the pixel positions. The first ‘triangulation’ method uses that the distance travelled and rotation between two frames is known. The second ‘plane projection’ method is an optimisation problem which consists of finding the variables which result in lowest error, and through this determine the cone distances and car speed. The map of the surrounding cones is moved according to the estimated velocity and rotation of the car such that the car is always placed at the origin, allowing for use of multiple detections to improve accuracy. The third ‘distance from cone height’ method works by using the size of the cone detections in order to determine the approximate distance of each cone, use this to determine the approximate angle of the camera and then use the median angle to make the final distance estimates. The triangulation method was shown to be completely unsuitable for mono-camera use. The plane projection method was shown to be unreliable, likely due to a relatively small number of visible cones and a too large noise amplitude of detections from YOLO. The distance from cone height method was shown to be the best out of the tested methods, as it was simple, fast and quite reliable. However, this method still had an error approximately 1.4 times larger than what is advertised by commercial stereo camera systems.
- Post360World A mobile app for creating and sharing 360° images(2017) Boking, Oskar; Helsing, Jonathan; Kulaglic, Amar; Lind, John; Mihajlovic, Nebojsa; Petersson, Anna; Chalmers tekniska högskola / Institutionen för data- och informationsteknik (Chalmers); Chalmers University of Technology / Department of Computer Science and Engineering (Chalmers)This report details the construction of 360World, an Android based prototype for a social media platform, the purpose of which is facilitating the capture and location focused sharing of 360 panorama pictures. The project encompasses the development of an Android application, a database for storing user information and the interface between these, as well as the configuration of hosting servers. The application makes use of algorithms from the OpenCV code library which are used to stitch multiple captured images into a single 360 panorama image; an image which can then be shared with the help of features that are typical for social media platforms, namely users and friends. 360World also has an innovative map-based way of visualising user profiles. Social media as an industry has been on the rise since its inception, and picture sharing is one of its major features; 360 pictures, however, are still relatively fringe. In this project, we explore one possible way 360 pictures could be utilised in a social media setting. The project resulted in a working prototype with which users can create, and share 360 panoramic images via map-based image presentation.