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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

機能性エラストマーの数値解析理論に関する研究 / キノウセイ エラストマー ノ スウチ カイセキ リロン ニ カンスル ケンキュウ

石川, 覚志 25 May 2009 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第14836号 / 工博第3133号 / 新制||工||1469(附属図書館) / 27242 / UT51-2009-F478 / 京都大学大学院工学研究科マイクロエンジニアリング専攻 / (主査)教授 小寺 秀俊, 教授 北條 正樹, 教授 田畑 修 / 学位規則第4条第1項該当
2

A Polarizable and Transferable Carbon Dioxide Potential for Materials Simulation

Mullen, Ashley Lynn 01 January 2013 (has links)
Intermolecular potential energy functions for CO2 have been developed from first principles for use in heterogeneous systems, including one with explicit polarization. The intermolecular potentials have been expressed in a transferable form and parameterized from nearly exact electronic structure calculations. Models with and without explicit many-body polarization effects, known to be important in simulation of interfacial processes, are constructed. The models have been validated on pressure-density isotherms of bulk CO2 and adsorption in three metal-organic framework (MOF) materials. The present models appear to offer advantages over high quality fluid/liquid state potentials in describing CO2 interactions in interfacial environments where sorbates adopt orientations not commonly explored in bulk fluids. Thus, the nonpolar CO2-PHAST and polarizable CO2-PHAST* potentials are recommended for materials/interfacial simulations.
3

Indentation and penetration of a spherical elastic membrane filled with fluid

Aboudzadeh Deris, Amir Hosein 16 January 2014 (has links)
The applications of elastic membrane range from determining the mechanical properties of biological cells by indentation tests to predicting the deformed shape of a large commercial tent structure. In this work, direct membrane theory and a particular Varga strain energy function are used to model the indentation and puncturing of an isotropic spherical elastic membrane containing a fluid with a rigid indenter. The balance laws are applied to obtain the governing differential equations and numerical shooting method is used to solve them. Furthermore, a global mode of failure is established by computing the energy stored at the punctured membrane and this value determines a critical value for the energy of the membrane beyond which the punctured state of the membrane is energetically preferred. An additional mode of failure is identified in which the membrane loses local convexity requirements and it corresponds to the local loss of elastic behavior of the membrane. / Graduate / 0548 / deris@Uvic.ca
4

Mixed model predictive control with energy function design for power system

Tavahodi, Mana January 2007 (has links)
For reliable service, a power system must remain stable and capable of withstanding a wide range of disturbances especially for the large interconnected systems. In the last decade and a half and in particular after the famous blackout in N.Y. U.S.A. 1965, considerable research effort has gone in to the stability investigation of power systems. To deal with the requirements of real power systems, various stabilizing control techniques were being developed over the last decade. Conventional control engineering approaches are unable to effectively deal with system complexity, nonlinearities, parameters variations and uncertainties. This dissertation presents a non-linear control technique which relies on prediction of the large power system behaviour. One example of a large modern power system formed by interconnecting the power systems of various states is the South-Eastern Australian power network made up of the power systems of Queensland, New South Wales, Victoria and South Australia. The Model Predictive Control (MPC) for the total power system has been shown to be successful in addressing many large scale nonlinear control problems. However, for application to the high order problems of power systems and given the fast control response required, total MPC is still expensive and is structured for centralized control. This thesis develops a MPC algorithm to control the field currents of generators incorporating them in a decentralized overall control scheme. MPC decisions are based on optimizing the control action in accordance with the predictions of an identified power system model so that the desired response is obtained. Energy Function based design provides good control for direct influence items such as SVC (Static Var Compensators), FACTS (Flexible AC Transmission System) or series compensators and can be used to define the desired flux for generator. The approach in this thesis is to use the design flux for best system control as a reference for MPC. Given even a simple model of the relation between input control signal and the resulting machine flux, the MPC can be used to find the control sequence which will start the correct tracking. The continual recalculation of short time optimal control and then using only the initial control value provides a form of feedback control for the system in the desired tracking task but in a manner which retains the nonlinearity of the model.
5

Aplicação de funções energia generalizadas de controle no projeto de reguladores para TCSCs em sistemas elétricos de potência / Application of control generalized energy function on design of regulators for TCSCs in electric power systems

Daniel Souto Siqueira 06 March 2017 (has links)
O dispositivo TCSC vem sendo utilizado com grande eficiência em sistemas elétricos de potência para melhoriada estabilidade transitóriaa e para fornecer amortecimento às oscilações eletromecânicas.Diversos trabalhos vêm sendo desenvolvidos como intuito desintetizar leis de controle para estes dispositivos. A maioria das técnicas empregadas para o projeto de controle em sistemas elétricos de potência utilizam modelos linearizados. Controladores projetados com técnicas lineares podem perder eficiência quando este ponto de operação varia de forma significativa. Controladores não lineares podem oferecer maior robustez a estas variações. Dentre várias técnicas de projeto de controle não linear, os métodos baseado sem funções de Lyapunov e/ou funções energia têm sido amplamente utilizados em sistemas elétricos de potência. Estas técnicas requerem a existência de uma função de Lyapunov e/ou função energia para o projeto, entretanto, mostrou-se que não existem funções de Lyapunov e/ou funções energia gerais para modelos de sistemas elétricos mais complexos que consideram, por exemplo, as perdas do sistema.Funções energia generalizadas (FEG) surgiram como uma alternativa para lidar com estas classes de modelos que apresentam comportamento complexo. Apresentamos neste trabalho uma função energia generalizada para modelos de sistemas elétricos de potência preservando a estruturada rede elétrica, comum modelo de terceira ordem para os geradores síncronos e considerando as perdas no sistema de transmissão. Com a FEG proposta, sintetizamos leis de controle não lineares para dispositivos TCSC, que independe da topologia da rede, utilizando sinais de realimentação locais e/ou remotos. As leis de controle projetadas melhoram significativamente a dinâmica do sistema e aumentam consideravelmente a região de estabilidade do sistema. / The TCSC device has been used with great efficiency in electric power systems to improve transient stability and to provide damping to electromechanical oscillations. Several studies have been developed in order to synthesize control laws for these devices. Most of the techniques used to design controller in electric power systems use linearized models. Controllers designed with linear techniques can lose efficiency when the operating point varies significantly. Nonlinear controllers can provide robustness to these variations. Among various techniques for non linear control design, the ones based on Lyapunov functions and/or energy function shave been widely used in electric power systems. These techniques require the existence of a Lyapunov function and/or energy function for the design, however, it was shown the non existence of Lyapunov function and/or general energy function for comprehensive electrical power system models, such as,system with losses. Generalized energy functions emerged as an alternative to deal with these classes of models that exhibit complex behavior. Herewer develop a generalized energy function to electrical power system models preserving the structure of the network, with a third-order model for synchronous generators and considering losses in the transmission system. With the proposed generalized energy function, nonlinear control laws are synthesized for TCSC devices, which are independent of the network topology, employ local and/or remote feedback signals. The designed control laws significantly improve the system dynamics and greatly increase stability regions of electrical power system.
6

Aplicação de funções energia generalizadas de controle no projeto de reguladores para TCSCs em sistemas elétricos de potência / Application of control generalized energy function on design of regulators for TCSCs in electric power systems

Siqueira, Daniel Souto 06 March 2017 (has links)
O dispositivo TCSC vem sendo utilizado com grande eficiência em sistemas elétricos de potência para melhoriada estabilidade transitóriaa e para fornecer amortecimento às oscilações eletromecânicas.Diversos trabalhos vêm sendo desenvolvidos como intuito desintetizar leis de controle para estes dispositivos. A maioria das técnicas empregadas para o projeto de controle em sistemas elétricos de potência utilizam modelos linearizados. Controladores projetados com técnicas lineares podem perder eficiência quando este ponto de operação varia de forma significativa. Controladores não lineares podem oferecer maior robustez a estas variações. Dentre várias técnicas de projeto de controle não linear, os métodos baseado sem funções de Lyapunov e/ou funções energia têm sido amplamente utilizados em sistemas elétricos de potência. Estas técnicas requerem a existência de uma função de Lyapunov e/ou função energia para o projeto, entretanto, mostrou-se que não existem funções de Lyapunov e/ou funções energia gerais para modelos de sistemas elétricos mais complexos que consideram, por exemplo, as perdas do sistema.Funções energia generalizadas (FEG) surgiram como uma alternativa para lidar com estas classes de modelos que apresentam comportamento complexo. Apresentamos neste trabalho uma função energia generalizada para modelos de sistemas elétricos de potência preservando a estruturada rede elétrica, comum modelo de terceira ordem para os geradores síncronos e considerando as perdas no sistema de transmissão. Com a FEG proposta, sintetizamos leis de controle não lineares para dispositivos TCSC, que independe da topologia da rede, utilizando sinais de realimentação locais e/ou remotos. As leis de controle projetadas melhoram significativamente a dinâmica do sistema e aumentam consideravelmente a região de estabilidade do sistema. / The TCSC device has been used with great efficiency in electric power systems to improve transient stability and to provide damping to electromechanical oscillations. Several studies have been developed in order to synthesize control laws for these devices. Most of the techniques used to design controller in electric power systems use linearized models. Controllers designed with linear techniques can lose efficiency when the operating point varies significantly. Nonlinear controllers can provide robustness to these variations. Among various techniques for non linear control design, the ones based on Lyapunov functions and/or energy function shave been widely used in electric power systems. These techniques require the existence of a Lyapunov function and/or energy function for the design, however, it was shown the non existence of Lyapunov function and/or general energy function for comprehensive electrical power system models, such as,system with losses. Generalized energy functions emerged as an alternative to deal with these classes of models that exhibit complex behavior. Herewer develop a generalized energy function to electrical power system models preserving the structure of the network, with a third-order model for synchronous generators and considering losses in the transmission system. With the proposed generalized energy function, nonlinear control laws are synthesized for TCSC devices, which are independent of the network topology, employ local and/or remote feedback signals. The designed control laws significantly improve the system dynamics and greatly increase stability regions of electrical power system.
7

Controle não linear aplicado a dispositivos FACTS em sistemas elétricos de potência / Nonlinear control applied to FACTS devices in power systems

Daniel Souto Siqueira 24 April 2012 (has links)
O TCSC é um dos compensadores dinâmicos mais eficazes empregados em Sistemas Elétricos de Potência, pois, oferece um ajuste flexível, de forma rápida e confiável, possibilitando a aplicação de teorias avançadas no seu controle. Estes dispositivos podem desempenhar funções importantes para a operação e o controle do sistema, trazendo inúmeros benefícios. Devido aos benefícios que o uso deste dispositivo oferece, uma grande quantidade de trabalhos vem sendo desenvolvidos com o intuito de sintetizar leis de controle para o mesmo. Porém, a maioria destes trabalhos é fundamentado em técnicas de controle clássico, isto é, projetando leis de controle baseado em sistemas linearizados e para pontos específicos da operação. Estas técnicas de análise entretanto, não garantem que para perturbações que levam o sistema para pontos distantes daqueles usados no projeto do controlador, a atuação do controlador seja eficaz e contribua assim para a estabilização do sistema. Visando o estudo mais aprofundado dos fenômenos que ocorrem nos sistemas físicos, modelos não lineares vêm sendo empregados, e as técnicas de projeto de controladores baseadas nesses modelos, são cada vez mais desenvolvidas. Neste trabalho será empregada a técnica de controle não linear baseada na Função Energia Generalizada de Controle para síntese de leis de controles estabilizantes para os dispositivos TCSC considerando, na modelagem, as perdas do sistema de transmissão. Esta técnica foi desenvolvida recentemente por SILVA et al. (2009), onde as ideias de Função de Lyapunov de Controle para uma classe maior de problemas foram desenvolvidas. Além de permitir o projeto do controlador, a técnica fornece estimativas da região de estabilidade do sistema e, portanto, podendo subsidiar a avaliação sistemática da contribuição do controlador na estabilidade transitória. / The TCSC is one of the most effective dynamic compensators used in electric power systems, offering a flexible adjustment, quickly and reliably, enabling the application of advanced theories in their control. These devices can play important roles for the operation and control of the networks, bringing many benefits. Because of the beneficial use of these devices a large amount of work has been developed in order to synthesize their control laws. However most of these studies are based on the classical control techniques, designing control laws based on linearized systems at specific operating points. However, these techniques do not guarantee that system disturbances which lead to operating points far away from those used for the controller design, the performance of the controller will be effective contributing to the system stabilization. Aiming to further studies and understanding of the physical phenomena occurring in the real world systems, nonlinear models have being employed in the controller design and techniques based on these methodologies have been proposed as never. In this work the technique of nonlinear control based on the Generalized Control Energy Function, for synthesis of control laws, which stabilize the TCSC devices considering the losses in the system transmission lines are employed. These techniques were recently developed by SILVA et al. (2009), and they extend the ideas of Control Lyapunov Function for a larger class of problems. Besides allowing the controller design, the technique provides estimates of the system stability region and therefore can support the systematic evaluation of the contribution to the transient stability controller.
8

Controle não linear aplicado a dispositivos FACTS em sistemas elétricos de potência / Nonlinear control applied to FACTS devices in power systems

Siqueira, Daniel Souto 24 April 2012 (has links)
O TCSC é um dos compensadores dinâmicos mais eficazes empregados em Sistemas Elétricos de Potência, pois, oferece um ajuste flexível, de forma rápida e confiável, possibilitando a aplicação de teorias avançadas no seu controle. Estes dispositivos podem desempenhar funções importantes para a operação e o controle do sistema, trazendo inúmeros benefícios. Devido aos benefícios que o uso deste dispositivo oferece, uma grande quantidade de trabalhos vem sendo desenvolvidos com o intuito de sintetizar leis de controle para o mesmo. Porém, a maioria destes trabalhos é fundamentado em técnicas de controle clássico, isto é, projetando leis de controle baseado em sistemas linearizados e para pontos específicos da operação. Estas técnicas de análise entretanto, não garantem que para perturbações que levam o sistema para pontos distantes daqueles usados no projeto do controlador, a atuação do controlador seja eficaz e contribua assim para a estabilização do sistema. Visando o estudo mais aprofundado dos fenômenos que ocorrem nos sistemas físicos, modelos não lineares vêm sendo empregados, e as técnicas de projeto de controladores baseadas nesses modelos, são cada vez mais desenvolvidas. Neste trabalho será empregada a técnica de controle não linear baseada na Função Energia Generalizada de Controle para síntese de leis de controles estabilizantes para os dispositivos TCSC considerando, na modelagem, as perdas do sistema de transmissão. Esta técnica foi desenvolvida recentemente por SILVA et al. (2009), onde as ideias de Função de Lyapunov de Controle para uma classe maior de problemas foram desenvolvidas. Além de permitir o projeto do controlador, a técnica fornece estimativas da região de estabilidade do sistema e, portanto, podendo subsidiar a avaliação sistemática da contribuição do controlador na estabilidade transitória. / The TCSC is one of the most effective dynamic compensators used in electric power systems, offering a flexible adjustment, quickly and reliably, enabling the application of advanced theories in their control. These devices can play important roles for the operation and control of the networks, bringing many benefits. Because of the beneficial use of these devices a large amount of work has been developed in order to synthesize their control laws. However most of these studies are based on the classical control techniques, designing control laws based on linearized systems at specific operating points. However, these techniques do not guarantee that system disturbances which lead to operating points far away from those used for the controller design, the performance of the controller will be effective contributing to the system stabilization. Aiming to further studies and understanding of the physical phenomena occurring in the real world systems, nonlinear models have being employed in the controller design and techniques based on these methodologies have been proposed as never. In this work the technique of nonlinear control based on the Generalized Control Energy Function, for synthesis of control laws, which stabilize the TCSC devices considering the losses in the system transmission lines are employed. These techniques were recently developed by SILVA et al. (2009), and they extend the ideas of Control Lyapunov Function for a larger class of problems. Besides allowing the controller design, the technique provides estimates of the system stability region and therefore can support the systematic evaluation of the contribution to the transient stability controller.
9

Spectroscopic Studies of Pyridine and its Isotopomer, 2-Fluoro- and 3-Fluoropyridine, 1,3-Butadiene and Its Isotopomers

Boopalachandran, Praveenkumar 2011 December 1900 (has links)
The infrared, Raman and ultraviolet spectra of pyridine-d0 and pyridine-d5 were recorded and assigned with a focus on the low-frequency vibrational modes in the S1(n,pi*) electronic excited state. An energy map for the low-frequency modes was constructed and the data for the v18 mode allowed a highly anharmonic one-dimensional potential energy function to be determined for the S1 excited state. In this S1(n,pi*) state, pyridine is quasi-planar and very floppy with a barrier to planarity of 3 cm^-1. The infrared, Raman and ultraviolet spectra of 2-fluoropyridine (2FPy) and 3-fluoropyridine (3FPy) have been collected and assigned. For 2FPy about 150 bands were observed for the transitions to the vibronic levels of the S(pi, pi*) state at 38,030.4 cm^-1. For 3FPy more than a hundred absorption bands associated with the S(n,pi*) state at 35,051.7 cm^-1 and about forty broad bands associated with the S(pi, pi*) state at 37,339 cm^-1 were observed. The experimental work was complemented by ab initio calculations and these also provided calculated structures for 2FPy, 3FPy, and pyridine. They showed that the fluorine atom on the ring participates in the pi bonding. The gas-phase Raman spectra of 1,3-butadiene and its 2,3-d2, 1,1,4,4-d4, and d6 isotopomers have been recorded with high sensitivity in the region below 350 cm-1, in order to investigate the internal rotation (torsional) vibration. The data for all the isotopomers were then fit using a one-dimensional potential energy function of the form V = (1/2)Sigma(Vn(1-cos (phi))). The energy difference between trans and gauche forms was determined to be about 1030 cm^-1 (2.94 kcal/mol), and the barrier between the two equivalent gauche forms to be about 180 cm^-1 (0.51 kcal/mol), which agrees well with high-level ab initio calculations. The results from an alternative set of assignments also fits the data quite well are also presented. Combination and hot band series involving the v13 torsional vibration of the trans rotamer were observed for each of the butadiene isotopomers. In addition, the high signal to noise of the Raman spectra made it possible to detect several dozen bands of the gauche rotor which makes up only about 2% of the molecules at ambient temperature.
10

繰返し荷重を加えたTiNi形状記憶合金ワイヤの応力ーひずみー温度関係の計測および数値解析

内藤, 尚, NAITO, Hisashi, 松崎, 雄嗣, MATSUZAKI, Yuji, 池田, 忠繁, IKEDA, Tadashige, 佐々木, 敏幸, SASAKI, Toshiyuki 03 1900 (has links)
No description available.

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