This master´s thesis deals with the indication and localization of earth faults in overhead lines. Earth fault is the most frequently occurring type of fault in medium voltage overhead lines – it covers approx. 95% of all faults and is very difficult to indicate and localize them correctly and in time with currently available methods on the market. Therefore is very important to study earth fault and its indication, localization. The thesis consists of a theoretical and a practical part. The theoretical part deals with faults in overhead networks with different type of neutral grounding, mainly with one phase to the ground fault in the compensated, ungrounded, solidly grounded and via resistance grounded networks. Most of the theoretical part is dedicated to one phase to the ground fault in the compensated and ungrounded networks, where this type fault is called the earth fault. In the compensated and ungrounded networks is described in details behavior – voltage and current relations during both steady state and transient state earth fault. The theoretical part is further dedicated to detection methods of earth faults and their preconditions for use. There is described also in details the complete procedure of earth fault detection, which includes indication, unhealthy feeder determination and exact position or line section localization. End of the theoretical part is then focused on determination of accuracy requirements for measurement of basic quantities and computation of other parameters. The practical part deals with a work at medium distribution network model, which includes familiarization with the model, detailed verification of its functionality and behavior during the earth fault, obtaining faults records and algorithmization of methods: method of qu – diagram and method of first half - period, which are able to detect unhealthy feeder. This part of the thesis was put together based on a demand of company Mega, corp., which wanted to verify function of both above mentioned and by them not yet tested methods.

<p>The miniaturization and thinning of wearable, soft robotics and medical devices are soon to require higher performance modeling as the physical flexibility causes direct impacts on the electrical characteristics of the circuit – changing its behavior. As a representative flexible electronic component, the organic field effect transistor (OFET) has attracted much attention in its manufacturing as well as applications. However, as the strain and stress effects are integrated into multiphysics modelers with deeper interactions, the computational complexity and accuracy of OFET modeling is resurfacing as a limiting bottleneck.</p><p>The dissertation was organized into three interrelated studies. In the first study, the Mass-Spring-Damper (MSD) model for an inverted staggered thin film transistor (TFT) was proposed to investigate the TFT’s internal stress/strain fields, and the strain effects on the overall characteristics of the TFT. A comparison study with the finite element analysis (FEA) model shows that the MSD model can reduce memory usage and raises the computational convergence speed for rendering the same results as the FEA. The second study developed the generalized solid-state model by incorporating the density of trap states in the band structure of organic semiconductors (OSCs). The introduction of trap states allows the generalized solid-state model to describe the electrical characteristics of both inorganic TFTs and organic field-effect transistors (OFETs). It is revealed through experimental verification that the generalized solid-state model can accurately characterize the bending induced electrical properties of an OFET in the linear and saturation regimes. The third study aims to model the transient and steady-state dynamics of an arbitrary organic semiconductor device under mechanical strain. In this study, the fractional drift-diffusion (Fr-DD) model and its computational scheme with high accuracy and high convergence rate were proposed. Based on simulation and experimental validation, the transconductance and output characteristics of a bendable OFET were found to be well determined by the Fr-DD model not only in the linear and saturation regimes, but also in the subthreshold regime.</p>

No description available.

No description available.

Vodní energie se nyní stala nejlepším zdrojem elektrické energie na zemi. Vyrábí se pomocí energie poskytované pohybem nebo pádem vody. Historie dokazuje, že náklady na tuto elektrickou energii zůstávají konstantní v průběhu celého roku. Vzhledem k mnoha výhodám, většina zemí nyní využívá vodní energie jako hlavní zdroj pro výrobu elektrické energie.Nejdůležitější výhodou je, že vodní energie je zelená energie, což znamená, že žádné vzdušné nebo vodní znečišťující látky nejsou vyráběny, také žádné skleníkové plyny jako oxid uhličitý nejsou vyráběny, což činí tento zdroj energie šetrný k životnímu prostředí. A tak brání nebezpečí globálního oteplování. Použití internetové techniky k ovladání několika vodních elektráren má velmi významné výhody, jako snížení provozních nákladů a flexibilitu uspokojení změny poptávky po energii na straně spotřeby. Také velmi efektivně čelí velkým narušením elektrické sítě, jako je například přidání nebo odebrání velké zátěže, a poruch. Na druhou stranu, systém získávání dat poskytuje velmi užitečné informace pro typické i vědecké analýzy, jako jsou ekonomické náklady, predikce poruchy systémů, predikce poptávky, plány údržby, systémů pro podporu rozhodování a mnoho dalších výhod. Tato práce popisuje všeobecný model, který může být použit k simulaci pro sběr dat a kontrolní systémy pro vodní elektrárny v prostředí Matlab / Simulink a TrueTime Simulink knihovnu. Uvažovaná elektrárna sestává z vodní turbíny připojené k synchronnímu generátoru s budicí soustavou, generátor je připojen k veřejné elektrické síti. Simulací vodní turbíny a synchronního generátoru lze provést pomocí různých simulačních nástrojů. V této práci je upřednostňován SIMULINK / MATLAB před jinými nástroji k modelování dynamik vodní turbíny a synchronního stroje. Program s prostředím MATLAB SIMULINK využívá k řešení schematický model vodní elektrárny sestavený ze základních funkčních bloků. Tento přístup je pedagogicky lepší než komplikované kódy jiných softwarových programů. Knihovna programu Simulink obsahuje funkční bloky, které mohou být spojovány, upravovány a modelovány. K vytvoření a simulování internetových a Real Time systémů je možné použít bud‘ knihovnu simulinku Real-Time nebo TRUETIME, v práci byla použita knihovna TRUETIME.

Made available in DSpace on 2011-05-04T12:36:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2009 / Este trabalho propõe analisar o fenômeno da terceirização desenvolvido ao longo das duas últimas décadas em Bio-Manguinhos. Trata-se de um estudo de caso realizado na unidade de produção de vacinas e reagentes para diagnóstico da Fundação Oswaldo Cruz. Inicialmente foi realizado um estudo de cenário, analisando a política de gestão do trabalho desenvolvida pelo Estado brasileiro para as instituições públicas. A seguir, a análise passou a verificar a inserção da Fiocruz nessas políticas, desde a sua criação e no decorrer de vigência de diferentes formas de contratação, alternando da extrema rigidez para a total flexibilidade sempre com foco na gestão do trabalho, e, como essas políticas se refletiram no desempenho de Bio-Manguinhos. Baseado no contexto da conformação do Estado e na análise do desempenho da unidade, o trabalho critica a falta de planejamento e de prospecção dessas políticas, que favoreça a inovação de processos, produtos e procedimentos e o desempenho pleno de uma unidade de produção de insumos para a saúde, tão necessários ao atendimento das necessidades da população brasileira. Critica também, a ausência de um modelo de Estado consolidado que sirva de arcabouço à formulação dessas políticas. Devido às fortes críticas dos órgãos de controle acerca da extrapolação dos limites da terceirização praticada nas últimas duas décadas e à falta de definição clara desses marcos legais, o trabalho apresenta uma metodologia baseada nas atribuições dos cargos do plano de carreiras da Fiocruz e culmina com a apresentação de uma matriz de atribuições passíveis de serem realizadas por contratação indireta. Conclui pela necessidade de convivência de dois quadros de trabalhadores: um permanente formado por servidores, estáveis e de carreira e outro flexível, executado por contratação indireta, de caráter eventual, temporário ou de apoio às atividades relacionadas à missão de Bio-Manguinhos. O trabalho ainda sugere a aplicação da mesma metodologia às demais unidades da Fiocruz e que a instituição afirme, frente aos órgãos de controle, quais atividades que ela precisa manter no quadro de servidores permanente e quais ela quer delegar a terceiros sem contudo, ferir a legislação vigente. Por fim, constata-se que a metodologia apresentada ameniza, mas não resolve o problema, dessa forma, recomenda-se à Fiocruz buscar mecanismos que altere o modelo de gestão pelo qual está submetida a fim de viabilizar as duas formas de incorporação de mão-de-obra.