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Made available in DSpace on 2015-05-08T14:57:19Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1298323 bytes, checksum: 6a19c3b38cf846b711c2c52ac67ab30a (MD5) Previous issue date: 2014-11-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A thermoelectric generator is a solid-state temperature dependent device that provide power generation on thermoelectric conversion. For that, the thermoelectric modules needs a temperature difference to ensure the thermoelectric conversion process. However, being subject to temperature variations may compromise the thermoelectric generator lifetime. Thus, in order to evaluate the temperature variation (thermal cycling) that the thermoelectric generators are exposed, this work has proposed an experimental platform that submits the thermoelectric generators modules to thermal cycling. With the experimental platform proposed the parameters of the thermoelectric generators may be to investigate properly. To evaluate the degradation effects on TEG the parameters were evaluated before the thermal cycling and then the parameters were evaluated after the thermal cycling process. At the research end, the parameters are presented by a comparative table with parameters evaluation before the thermal cycling and parameters evaluation after thermal cycling which brings to the experimental platform reliability. / Objetivo: Os geradores termoelétricos são dispositivos de estado sólido que utilizam a diferença de temperatura para a conversão em energia elétrica. No entanto, submeter os geradores termoelétricos a variações de temperatura pode comprometer o tempo de vida desses dispositivos. Assim, com o objetivo de investigar a possível influência das variações de temperatura ciclos térmicos a que os módulos geradores termoelétricos (TEGs) estão expostos, este trabalho desenvolveu uma plataforma experimental capaz de submeter TEGs à influência de ciclos térmicos, permitindo assim que os TEGs possam ser avaliados. Para constatar os efeitos na degradação do TEG, alguns parâmetros foram avaliados antes da aplicação dos ciclos térmicos e após uma sequência de ciclos térmicos. Ao fim da pesquisa, as avaliações feitas nos parâmetros são apresentadas em uma tabela comparativa, em que são apresentados os valores obtidos antes da aplicação dos ciclos térmicos e os valores dos parâmetros após a aplicação dos ciclos térmicos.

Databases are very complex systems that require database system administrators to perform system tuning in order to achieve optimal performance. Memory tuning is vital to the performance of a database system because when the database workload exceeds its memory capacity, the results of the queries running on a system are delayed and can cause substantial user dissatisfaction. In order to solve this problem, this thesis presents a platform modeled after a closed control feedback loop to control the level of multi-query processing. Utilizing this platform provides two key assets. First, the system identification is acquired, which is one of two crucial steps involved in developing a closed feedback loop. Second, the platform provides a means to experimentally study database tuning problem and verify the effectiveness of research ideas related to database performance.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-11-13T12:55:39Z No. of bitstreams: 1 Augusto Hafemeister_.pdf: 17337125 bytes, checksum: bb32daa4e0367e3ae60ab686e81c9ef9 (MD5) / Made available in DSpace on 2018-11-13T12:55:39Z (GMT). No. of bitstreams: 1 Augusto Hafemeister_.pdf: 17337125 bytes, checksum: bb32daa4e0367e3ae60ab686e81c9ef9 (MD5) Previous issue date: 2018-05-22 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CFC/CRCs - Conselho Federal de Contabilidade / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / O presente trabalho apresenta o desenvolvimento de uma interface de supervisão para integrar duas topologias diferentes de sistemas fotovoltaicos instalados na Unisinos, viabilizando estudos locais e a distância, ou seja, permitindo que alunos e pesquisadores de outras comunidades acadêmicas possam visualizar dados em tempo real e fazer intercâmbio de informações e discussões à cerca deste assunto. Para atingir as metas estabelecidas, o sistema foi desenvolvido sobre o software LabVIEW®, sendo as medições das grandezas elétricas e térmicas enviadas automaticamente para o Microsoft OneDrive®, o qual está em sincronismo com o site da Plataforma Experimental de Pesquisa e Ensino em ESFV. Além da integração dos sistemas mencionados, implementou-se um hardware para ajustar o ângulo de inclinação de um módulo fotovoltaico, agregou-se um traçador de curvas I-V e P-V, o qual permite fazer análises em condições reais de operação e também foram instalados dois sensores para medir a irradiância no plano do gerador fotovoltaico, ambos com monitoramento de temperatura e devidamente calibrados. Contudo, o principal diferencial dessa pesquisa está nos resultados encontrados na utilização da interface, em que foi possível comparar a performance dos módulos variando o ângulo de inclinação, correlacionando-o com a irradiância e a temperatura em diferentes dias típicos. Para um caso específico, foi analisado o comportamento da curva I-V durante um período de sombreamento, onde a eficiência de conversão atingiu menos de 6% e a potência máxima entregue foi 40% menor, mesmo estando coberta apenas uma das 60 células que compõem o módulo. Esse fato reforça a importância da análise experimental da curva característica para avaliação da qualidade e do desempenho do sistema, bem como identificar defeitos nas células e/ou no diodo de bypass. Por fim, simulou-se um modelo matemático, com base nas características do módulo fotovoltaico utilizado, a fim de avaliar os impactos da variação de temperatura e irradiância e também validar os resultados encontrados na prática. / This work presents the development of a supervision interface to integrate two different topologies of photovoltaic systems installed in Unisinos, making possible local and distance studies, allowing students and researchers from other academic communities to view real time data and to exchange information and discussions on this subject. To achieve the established goals, the system was developed over LabVIEW® software, with measurements of electrical and thermal values automatically sent to Microsoft OneDrive®, which is in synchronism with the Photovoltaic Teaching and Research Experimental Platform website. In addition to the integration of the mentioned systems, a hardware was implemented to adjust the angle of inclination of a PV module, an I-V and P-V curve plotter was added, which allows to perform analyzes under real operating conditions and also installed two sensors to measure the irradiance in the plane of the PV generator, both with temperature monitoring and properly calibrated. However, the main difference of this research is in the results found in the use of the interface, in which it was possible to compare the performance of the modules by varying the angle of inclination, correlating it with the irradiance and the temperature on different typical days. For a specific case, the behavior of the I-V curve was analyzed during a shading period, where the conversion efficiency reached less than 6% and the maximum delivered power was 40% lower, even cover only one of the 60 cells that make up the module. This fact reinforces the importance of the experimental analysis of the characteristic curve to evaluate the quality and performance of the system, as well as to identify defects in the cells and/or bypass diode. Finally, a mathematical model was simulated, based on the characteristics of the PV module used, in order to evaluate the impacts of temperature and irradiance variation and to validate the results found in practice.

Les travaux de recherche de cette thèse s'inscrivent dans le cadre général de l'expertise des projets de stockage de déchets radioactifs en couche argileuse. La présence de failles dans ces roches peut modifier ses propriétés de perméabilité ; la détection des failles constitue donc un enjeu majeur. Depuis de nombreuses années, l'IRSN mène des travaux de recherche dans la station expérimentale de Tournemire où des failles à faible décalage vertical sont interceptées dans le milieu argileux depuis des ouvrages souterrains. Les travaux précédents ont montré la difficulté de détecter ces failles depuis des acquisitions de surface que cela soit en sismique réflexion, réfraction ou en électrique.Dans le cadre de cette thèse, nous avons proposé une nouvelle géométrie d'acquisition sismique en transmission (sources en surface-récepteurs dans les ouvrages souterrains). Pour traiter ces données, un code de tomographie a été développé afin de maîtriser parfaitement les paramètres d'inversion et aussi d'introduire de l'information a priori. De nombreux tests synthétiques ont ensuite été menés dans le souci d'analyser de manière fiable les résultats obtenus, notamment en termes de résolution et de pertinence de l'image. L'application de ce code de tomographie aux données en transmission nouvellement acquises permet de mettre en évidence pour la première fois une discontinuité des vitesses sismiques dans les calcaires et argilites de la Station Expérimentale de Tournemire. Cette anomalie de vitesse est localisée à l'aplomb de la zone de faille visible depuis les ouvrages souterrains et est aussi en accord avec les observations de surface. / Deep argillaceous formations have physical properties adapted to the radioactive waste disposal but their permeability properties can be modified by the presence of fractured zones; detection of these faulted zones are thus of primary importance. Several experiments have been led by IRSN in the Experimental Platform of Tournemire where faults with small vertical offsets in the deep argillaceous formation have been identified from underground installations. Some previous studies have shown the difficulty to detect this fractured zone from surface acquisitions using reflection or refraction seismic but also with electrical methods.We here propose a new seismic transmission acquisition geometry in where seismic sources are deployed at the surface and receivers are installed in the underground installations. In the scope to process these data, a new tomography algorithm has been developed in order to control the inversion parameters and also to introduce a priori information. Several synthetic tests have been led to reliably analyze the results in terms of resolution and relevance of the final image. A discontinuity of the seismic velocities in the limestones and argillites of the Tournemire Platform is evidenced for the first time by applying the algorithm to the data recently acquired. This low velocity anomaly is located just above the fracture zone visible from the underground installations and its location is also consistent with observations from the surface.

No description available.

A helicopter can be used to transport a load hanging from a suspension cable. This technique is frequently used in construction, firefighting, and disaster relief operations, among other applications. Unfortunately, the suspended load swings, which makes load positioning difficult and can degrade control of the helicopter. This dissertation investigates the use of input shaping (a command-filtering technique for reducing vibration) to mitigate the load swing problem. The investigation is conducted using two different, but complementary, approaches. One approach studies manual tracking tasks, where a human attempts to make a cursor follow an unpredictably moving target. The second approach studies horizontal repositioning maneuvers on small-scale helicopter systems, including a novel testbed that limits the helicopter and suspended load to move in a vertical plane. Both approaches are used to study how input shaping affects control of a flexible element (the suspended load) and a driven base (the helicopter). In manual tracking experiments, conventional input shapers somewhat degraded control of the driven base but greatly improved control of the flexible element. New input shapers were designed to improve load control without negatively affecting base control. A method for adjusting the vibration-limiting aggressiveness of any input shaper between unshaped and fully shaped was also developed. Next, horizontal repositioning maneuvers were performed on the helicopter testbed using a human-pilot-like feedback controller from the literature, with parameter values scaled to match the fast dynamics of the model helicopter. It was found that some input shapers reduced settling time and peak load swing when applied to Attitude Command or Translational Rate Command response types. When the load was used as a position reference instead of the helicopter, the system was unstable without input shaping, and adding input shaping to a Translational Rate Command was able to stabilize the load-positioning system. These results show the potential to improve the safety and efficiency of helicopter suspended load operations.