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1	Development of Elastic Mechanism for actuation of Valve / Utveckling av elastisk mekanism för aktivering av ventil Menon, Nidhi January 2023 (has links) The HGR valve, or hot gas recirculation valve, is an essential component of modern internal combustion engines. Its main function is to reduce emissions of nitrous oxide (NOx), which is a harmful pollutant produced during combustion. This research focuses on developing a compliant mechanism for HGR valve activation, in order to minimize wear leakage and reduce the number of parts.However, the project faced challenges, including limitations in steel elasticity, fatigue due to high frequency operation, and high stress due to elastic deformation. In order to achieve the range of motion required for efficient valve operation, additional mechanisms were incorporated, resulting in dimensional limitations beyond those of the current design. 3D modeling of the concepts were constructed with the help of CATIA, and Finite element analysis was carried out on the same. The concepts were assessed based on stresses and the range of motion. A Pugh’s matrix was used to compare various concepts. A concept using Vulcanized silicone rubber was found to be feasible for the application, but further work is required to bring the concept to a usable state. / HGR-ventilen, eller varmgasåtercirkulationsventilen, är en viktig komponent i moderna förbränningsmotorer. Dess huvudsakliga funktion är att minska utsläppen av kväveoxid (NOx),som är ett skadligt förorenande ämne som produceras under förbränning. Denna forskning fokuserar på att utveckla en kompatibel mekanism för aktivering av HGR-ventilen, för att minimera läckage och minska antalet delar. Projektet stötte dock på utmaningar, bland annat begränsningar i stålets elasticitet, utmattning på grund av högfrekvent drift och hög stress på grund av elastisk deformation. För att uppnå det rörelseomfång som krävs för effektiv ventildrift införlivades ytterligare mekanismer, vilket resulterade i dimensionella begränsningar utöver dem i den nuvarande konstruktionen. 3D modellering av koncepten konstruerades med hjälp av CATIA, och Finite element-analys utfördes på samma. Koncepten utvärderades baserat på spänningar och rörelseomfång. En Pughs matris användes för att jämföra de olika koncepten. Ett koncept som använder vulkaniserat silikongummi visade sig vara genomförbart för applikationen, men ytterligare arbete krävs för att föra konceptettill ett användbart tillstånd. Compliant mechanism Engine HGR valve Heat gas recirculation Eftergivlig mekanism HGR-ventil läckage varmgasåtercirkulationsventilen Mechanical Engineering Maskinteknik
2	Synthesis and characterization of electrocatalytic graphene for electrochemical sensing and bioelectronics Osikoya, Adeniyi Olugbenga 02 1900 (has links) D. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / In this study, few layer graphene (Gr) and heteroatom graphene (HGr) were synthesized by chemical vapour deposition (CVD) method. Acetylene gas was used as carbon source for the synthesis of graphene, while a mixture of nitrobenzene and dichloromethane (ratio 1:1) were used as both carbon and dopant sources for the synthesis of the heteroatom graphene (HGr). A mixture of argon and nitrogen gases were carefully combined and used as carrier gasses and purge for both the synthesis of graphene and the synthesis of heteroatom graphene. X-ray diffraction (XRD) characterized showed that the as synthesized materials were crystalline materials, Raman spectroscopy indicated that the synthesized materials consist of sp2 hybridized carbon atoms, while scanning electron microscopy (SEM) and atomic force microscopy (AFM) results showed that the synthesized materials possess regions of 2 to 7 nm of thickness. Transmission electron microscopy (TEM) characterization also showed that the synthesized heteroatom graphene possesses about 5 to 7 layers with about 2 nm thickness, and x-ray photoelectron spectroscopy (XPS) result showed the presence of nitrogen, oxygen and chlorine in the lattice of the synthesized heteroatom graphene while the synthesized material still retained about 80% sp2 hybridization. The synthesized materials were used in the fabrication of modified bioelectrodes for electrobiocatalytic biosensing of glucose and hydroquinone. The fabricated bioelectrodes were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The CV characterization showed a diffusion-controlled electrode processes in al modified electrodes, while the EIS characterization showed the presence of both diffusion controlled and kinetic controlled impedance at the electrode-electrolyte interface. The fabricated GC/PEDOT-PSS/HGr/Lac modified bioelectrode exhibited a kinetic controlled impedance of 3150 Ω, while the fabricated GC/PEDOT-PSS/Gr/Lac modified bioelectrode exhibited a kinetic controlled impedance of 4138 Ω. Chronoamperometric experiments showed that the fabricated bioelectrodes exhibited swift electrobiocatalytic activity towards glucose and hydroquinone sensing respectively for graphene and heteroatom graphene. The graphene modified bioelectrode exhibited a linear response of 0.2 to 9.8 mM glucose concentration and a sensitivity of 87.0 μA/mM/cm2, while the heteroatom modified bioelectrode also exhibited a swift response to step by step addition of hydroquinone with a limit of detection of 2.07 μM and dynamic range of 2.07μM to 2.97 mM, thus indicating the tremendous potential of the materials in a wide range of electrobiocatalytic and bioelectronics applications. Synthesis Characterization Electrocatalytic graphene Electrochemical sensing Bioelectronics Chemical vapour deposition (CVD) Heteroatom graphene (HGr) Chronoamperometry Glucose oxidase Carbon Raman spectroscopy Dissertations, Academic -- South Africa Nanostructured materials. Chemistry -- Experiments. Carbon nanotubes. Graphene.
3	Creating Good User Experience in a Hand-Gesture-Based Augmented Reality Game / Användbarhet i ett handgestbaserat AR-spel Lam, Benny, Nilsson, Jakob January 2019 (has links) The dissemination of new innovative technology requires feasibility and simplicity. The problem with marker-based augmented reality is similar to glove-based hand gesture recognition: they both require an additional component to function. This thesis investigates the possibility of combining markerless augmented reality together with appearance-based hand gesture recognition by implementing a game with good user experience. The methods employed in this research consist of a game implementation and a pre-study meant for measuring interactive accuracy and precision, and for deciding upon which gestures should be utilized in the game. A test environment was realized in Unity using ARKit and Manomotion SDK. Similarly, the implementation of the game used the same development tools. However, Blender was used for creating the 3D models. The results from 15 testers showed that the pinching gesture was the most favorable one. The game was evaluated with a System Usability Scale (SUS) and received a score of 70.77 among 12 game testers, which indicates that the augmented reality game, which interaction method is solely based on bare-hands, can be quite enjoyable. AR Hand gestures Bare-hand interaction HGR Augmented reality usability user experience Manomotion ARKit Visual Odometry SLAM VO VIO 3D gestural interaction gesture recognition gesture tracking augmented environments Förstärkt verklighet 3D gestinteraktion gestigenkänning visuell odometri Manomotion ARKit Engineering and Technology Teknik och teknologier Interaction Technologies Interaktionsteknik Design Design Human Computer Interaction Probability Theory and Statistics Sannolikhetsteori och statistik Computer Systems Datorsystem Software Engineering Programvaruteknik

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