Toward the objective to create or to replace impaired tissues, it is essential to establish a culture process allowing tissue growth in vitro . The Petri dish culture or the traditional 2D culture has only a limited potential, mainly caused by a poor oxygen mass transfer to feed larger tissue constructs. In this project, an autonomous and complete bioprocess has been built to fullfill these needs. The developed reactor is versatile because many cell culture chamber designs can be connected to it. Two proportional-integral algorithms (PI) can control the dissolved oxygen concentration and the pH. The pressure, the temperature and mass flow rate are recorded in real time. An actuator allows mimicking the cardiac output flow. In this mémoire , it will be demonstrated how the reactor has been optimized to reduce the risk of bioburden. Also, the procedures to develop the control tools of the PI algorithm will be detailed. To characterize the reactor, a RTD study will be presented. To characterize the cell culture chamber, a permeability analysis using fluorescent microscopy and magnetic resonance imaging (MRI) will be exposed. Finally, two cell culture chamber designs to orient microvessel formation have been tested and these results will be presented.

Conical spouted beds have been commonly used for drying suspensions, solutions and pasty materials. They can also be utilized in many other processes, such as catalytic partial oxidation of methane to synthesis gas, coating of tablets, coal gasification and liquefaction, pyrolysis of sawdust or mixtures of wood residues. The main objectives of this work include both the experimental research and mathematical modelling of the conical spouted bed hydrodynamics. For experimental research, pressure transducers and static pressure probes were applied to investigate the evolution of the internal spout and the local static pressure distribution; optical fibre probes were utilized to measure axial particle velocity profiles and voidage profiles; the step tracer injection technique using helium as the tracer and thermal conductivity cells as detectors was used to investigate the gas mixing behaviour inside a conical spouted bed. It was found that many factors might affect calibration of the effective distance of an optical fibre probe. Therefore, a new calibration setup was designed and assembled, and a comprehensive sensitivity analysis was conducted to calibrate the optical probes used in this study. For mathematical modelling, a stream-tube model based on the bed structure inside a conical spouted bed was proposed to simulate partial spouting states. By introducing an adjustable parameter, this model is capable of predicting the total pressure drop under different operating conditions, and estimating axial superficial gas velocity profiles and gauge pressure profiles. A mathematical model based on characteristics of conical spouted beds and the commercial software FLUENT was also developed and validated using measured experimental data. The proposed new CFD model can simulate both stable spouting and partial spouting states, with an adjustable solids-phase source term. At stable spouting states, simulation results agree very well with almost all experimental data, such as static pressure profiles, axial particle velocity profiles, voidage profiles etc. A comprehensive sensitivity analysis was also conducted to investigate the effect of all possible factors on simulation results, including the fluid inlet profile, solid bulk viscosity, frictional viscosity, restitution coefficient, exchange coefficient, and solid phase source term. The proposed new CFD model was also used successfully to simulate gas mixing behaviours inside a conical spouted bed, and simulate cylindrical packed beds as well as cylindrical fluidized beds in one code package.

Conical spouted beds have been commonly used for drying suspensions, solutions and pasty materials. They can also be utilized in many other processes, such as catalytic partial oxidation of methane to synthesis gas, coating of tablets, coal gasification and liquefaction, pyrolysis of sawdust or mixtures of wood residues. The main objectives of this work include both the experimental research and mathematical modelling of the conical spouted bed hydrodynamics. For experimental research, pressure transducers and static pressure probes were applied to investigate the evolution of the internal spout and the local static pressure distribution; optical fibre probes were utilized to measure axial particle velocity profiles and voidage profiles; the step tracer injection technique using helium as the tracer and thermal conductivity cells as detectors was used to investigate the gas mixing behaviour inside a conical spouted bed. It was found that many factors might affect calibration of the effective distance of an optical fibre probe. Therefore, a new calibration setup was designed and assembled, and a comprehensive sensitivity analysis was conducted to calibrate the optical probes used in this study. For mathematical modelling, a stream-tube model based on the bed structure inside a conical spouted bed was proposed to simulate partial spouting states. By introducing an adjustable parameter, this model is capable of predicting the total pressure drop under different operating conditions, and estimating axial superficial gas velocity profiles and gauge pressure profiles. A mathematical model based on characteristics of conical spouted beds and the commercial software FLUENT was also developed and validated using measured experimental data. The proposed new CFD model can simulate both stable spouting and partial spouting states, with an adjustable solids-phase source term. At stable spouting states, simulation results agree very well with almost all experimental data, such as static pressure profiles, axial particle velocity profiles, voidage profiles etc. A comprehensive sensitivity analysis was also conducted to investigate the effect of all possible factors on simulation results, including the fluid inlet profile, solid bulk viscosity, frictional viscosity, restitution coefficient, exchange coefficient, and solid phase source term. The proposed new CFD model was also used successfully to simulate gas mixing behaviours inside a conical spouted bed, and simulate cylindrical packed beds as well as cylindrical fluidized beds in one code package.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-06-26T13:45:43Z No. of bitstreams: 1 EMANUEL PEREIRA SOARES - TESE (PPGCEMat) 2016.pdf: 5694808 bytes, checksum: 0e810a171e0ef5e6c6238f4884d08109 (MD5) / Made available in DSpace on 2018-06-26T13:45:43Z (GMT). No. of bitstreams: 1 EMANUEL PEREIRA SOARES - TESE (PPGCEMat) 2016.pdf: 5694808 bytes, checksum: 0e810a171e0ef5e6c6238f4884d08109 (MD5) Previous issue date: 2016-06-21 / A medida da Distribuição do Tempo de Residência (DTR) em tempo real durante o processo de extrusão permite realizar uma análise global do desempenho do equipamento (extrusora), proporcionando um melhor conhecimento do comportamento do fluxo do material durante todo o processo. Neste trabalho foi desenvolvido um sistema ótico (hardware e software) para detecção de curvas DTR em tempo real durante a extrusão de polímeros. O sistema de detecção teve sua eficiência validada. Os resultados obtidos sugeriram que o sistema foi capaz de detectar as curvas de DTR com um elevado número de pontos, bem como se mostrou sensível a variação na concentração e no tipo de traçador utilizado; além disso, foi possível confirmar a boa reprodutibilidade das medições o que qualificou o sistema para o levantamento das curvas de DTR em tempo real. Posteriormente, foram avaliados os efeitos nas alterações das variáveis de processamento sobre a forma e os parâmetros das curvas de DTR. Foi possível confirmar que a variação na taxa de alimentação possui uma maior influência sobre as curvas DTR do que a velocidade da rosca, fato este corroborado com a literatura. também constatou-se que as alterações no Índice de Fluidez do material de fluxo afetaram a dispersão (capacidade de mistura) nas curvas de DTR. A eficiência energética do processo de extrusão também foi analisada através do levantamento da energia mecânica dissipada e da energia mecânica especifica, foi apresentada uma correlação destes parâmetros energéticos com o tempo de residencia médio. Neste trabalho também foi utilizado uma ferramenta computacional (WinTXS™) para simular as condições de processamento experimentais; a partir daí realizou-se a comparação entre os dados medidos experimentalmente e os simulados, de modo a estabelecer um grau de concordância entre os mesmos. Os resultados obtidos permitiram comprovar que medição da DTR e a simulação computacional unidimensinal são ferramentas importantes no estudo do processo de extrusão de polímeros. / The measurement of Residence Time Distribution (RTD) in real time during the extrusion process allows a comprehensive analysis of equipment performance (extruder), providing a better understanding of the material flow behavior throughout the process. This work developed an optical system (hardware and software) to detect RTD curves in real time during the extrusion of polymers. The efficiency in the detection system was validated. The results obtained suggest that the system it was able to detect the RTD curves with a large number of points, and is sensitive to variations in the concentration and type of tracer used; furthermore, it was possible to confirm the good reproducibility of the measurements which qualify the system for lifting the RTD curves in real time. subsequently, we evaluated the effects of changes in processing variables on the form and parameters of the RTD curves. It was confirmed that the variation in feed rate has a larger influence on cornering RTD than the speed of the screw, a fact corroborated by the literature. It was also found that the change in Melt Index affect the flow of material dispersion (mixing capacity) in the RTD curves. The energy efficiency of the extrusion process was also analyzed by surveying the dissipated mechanical energy and mechanical energy specifies a correlation is presented these energy parameters with the average residence time. This work also used a computational tool (WinTXS ™) to simulate the processing conditions; there after it conducted a comparison between the experimentally measured and simulated data to establish the degree of agreement there between. Results show evidence that measurement of RTD and unidimensinal computer simulation is important tools in the study of polymer extrusion process.

Current computer-assisted pronunciation training (CAPT) tools are too focused on what technologies can do, rather than focusing on learner needs and pedagogy. They also lack an embodied perspective on learning. This thesis presents a Research through Design project exploring what kind of interactive design features can support second language learners’ pronunciation learning of segmental speech sounds with embodiment in mind. ComPron was designed: an open simulated prototype that supports learners in learning perception and production of new segmental speech sounds in a second language, by comparing them to native language speech sounds. ComProm was evaluated through think-aloud user tests and semi-structured interviews (N=4). The findings indicate that ComPron supports awareness of speech sound-movement connections, association building between sounds, and production of sounds. The design features that enabled awareness, association building, and speech sound production support are discussed and what ComPron offers in comparison to other CAPT-tools.

Involuntary loneliness is today considered to be a public health problem, and studies show that feeling lonely can have major negative effects on one's health. Project Omtanke and the social administration in Helsingborg has mapped a big problem with loneliness in Helsingborg, and has come to the conclusion that they need a website with the purpose of mitigating loneliness. Thus, this research project explores how a website should be designed to make people feel less lonely.  This thesis essay explores the research question with the approach Research Through Design (RtD). The research was conducted by conducting user research, creating a prototype and validating the design with users.  This thesis has come to the conclusion that a website with the purpose of supporting lonely individuals should include content providing help and support to all relevant target groups, such as educational content and help alternatives. It should also be designed with the goal to decrease the gap between available help and the people in need of help, by increasing awareness and reassuring personal relevance of available help. The website should also include functions that promote social contact between people, and be designed with the goal of being perceived as inclusive. The website prototype that was created in this thesis was well received by potential users. The users expressed in the validation of the website that they would like to use it, and that they believe it could help them with their loneliness.

Advancements in technology have rendered social media an indispensable means of social communication. However, among the vast amount of data exchanged between users, there is often limited space for meaningful conversation and the cultivation of deeper interpersonal connections. This dissertation adopts a research-through-design approach to explore the concept of Minimal Social Interaction Design, focusing on the use of colours as the primary tool for facilitating these interactions. The main objective of this project is to investigate: What meaning-making communication practices are produced or altered when using colour-based minimal social communication? To achieve this objective, the study involves an auto-ethnographic pre-study and three focus groups to examine minimal colour-based interactions among individuals and groups. Additionally, Drawing inspiration from the concepts of Calm and Slow Technology, this project includes the design and evaluation of an online platform dedicated to facilitating minimal colour-based social interactions. The qualitative data collected from the study indicates that by engaging in minimal colour-based interactions in different social contexts individuals would face both opportunities and challenges. These opportunities and challenges ultimately create a space for individuals to enhance their social awareness, engage in effective negotiation, deepen their understanding of their partners, and develop an intimate private language based on colours. / Teknikens framsteg har gjort sociala medier till ett oumbärligt verktyg för social kommunikation. Trots den enorma mängd data som utbyts mellan användare är det ofta begränsat utrymme för meningsfulla konversationer och kultivering av djupare och mer personliga relationer. I denna avhandling antas en forskning-genom-design-ansats för att utforska konceptet Minimal Social Interaction Design, med fokus på användningen av färger som det primära verktyget för att underlätta dessa interaktioner. Det primära målet med projektet är att undersöka: Vilka betydelseskapande kommunikationspraktiker uppstår eller förändras vid användning av färgbaserad minimal social kommunikation? Denna studie innefattar en auto-etnografisk förstudie med tre fokusgrupper för att undersöka minimala färgbaserade interaktioner bland individer och grupper. Därtill, med inspiration från koncepten Calm och Slow Technology, inkluderar projektet design och utvärdering av en online-plattform dedikerad till att underlätta minimala färgbaserade sociala interaktioner. De kvalitativa data som samlats in från studien indikerar att genom att deltaga i minimala färgbaserade interaktioner i olika sociala sammanhang så möter individer både möjligheter och utmaningar. Dessa möjligheter och utmaningar skapar i slutändan utrymme för individer att öka sin sociala medvetenhet, kunna förhandla effektivare, fördjupa sin förståelse för sina partners och utveckla ett intimt privat språk baserat på färger.

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The unique properties, such as large direct bandgap, excellent thermal stability, high μH × ns, of III-nitrides make them ideal candidates for both optoelectronic and high-speed electronic devices. In the past decades, great success has been achieved in commercialization of GaN based light emitting diodes (LEDs) and laser diodes (LDs). However, due to the lack of native substrates, thin films grown on sapphire or SiC substrates have high defect densities that degrade the device performance and reliability. Conventional epitaxy lateral overgrowth (ELO) can reduce dislocation densities down to ∼10-6 cm-2 in the lateral growth area, but requires ex situ photolithography steps. Hence, an in situ method using a SiNx interlayer (nano-scale ELOG) has emerged as a promising technique. The GaN templates prepared by this method exhibit a very low dislocation density (low-10-7 cm-2) and excellent optical and electrical properties. As a cost, such high quality GaN templates containing SiN, nanonetworks are not suitable for heterojunction field effect transistor (HFET) applications due to degenerate GaN:Si layer which serves as parallel conduction channel. This dissertation discusses the growth of low dislocation density GaN templates, by using the in situ SiNx nanonetwork for conductive templates, and the AIN buffer for semi-insulating templates. On SiN x nanonetwork templates, double-barrier RTD and superlattice (SL) exhibited negative differential resistances. Moreover, the injection current of Blue LEDs (450 nm) was improved ∼30%. On semi-insulating GaN templates, nearly lattice matched AlInN/AIN/GaN HFETs were successfully demonstrated and exhibited ∼ 1600 cm2/Vs and 17 600 cm2/Vs Hall mobilities at 300 K and 10 K, respectively. Those mobility values are much higher than literature reports and indicate that high quality HFETs can be realized in lattice matched AlInN/AIN/GaN, thereby solving the strain related issue. The attempt to use InGaN as the 2DEG channel has also been successfully implemented. A Hall mobility (1230 cm2/Vs) was achieved in a 12 nm InGaN channel HFET with AlInGaN barrier, which demonstrates the viability of InGaN channel HFETs.