20 resultados para conceptual variation
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Tese de doutoramento em Ciências da Educação
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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Mecânica
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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do Grau de Mestre em Engenharia do Ambiente,Perfil de Gestão e Sistemas Ambientais
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High speed trains, when crossing regions with abrupt changes in vertical stiffness of the track and/or subsoil, may generate excessive ground and track vibrations. There is an urgent need for specific analyses of this problem so as to allow reliable esimates of vibration amplitude. Full understanding of these phenomena will lead to new construction solutions and mitigation of undesirable features. In this paper analytical transient solutions of dynamic response of one-dimensional systems with sudden change of foundation stiffness are derived. Results are expressed in terms of vertical displacement. Sensitivity analysis of the response amplitude is also performed. The analytical expressions presented herein, to the authors’ knowledge, have not been published yet. Although related to one-dimensional cases, they can give useful insight into the problem. Nevertheless, in order to obtain realistic response, vehicle- rail interaction cannot be omitted. Results and conclusions are confirmed using general purpose commercial software ANSYS. In conclusion, this work contributes to a better understanding of the additional vibration phenomenon due to vertical stiffness variation, permitting better control of the train velocity and optimization of the track design.
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33rd IAHR Congress: Water Engineering for a Sustainable Environment
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Dissertation presented in fulfillment of the requirements for the Degree of Doctor of Philosophy in Biology (Molecular Genetics) at the Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa
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Proceedings of the Institution of Civil Engineers - Water Management 163 Issue WM6
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Neste artigo percorrem-se símbolos, conceitos, percepções e ícones que o Mundo e Visão do Mundo permutam através do homem enquanto observador qualificado. O autor defende o limiar de uma nova interpretação da realidade e do conhecimento profundamente transformados pela revolução informática. Compara-a às mudanças da Renascença, aborda a sua importância no dia-a-dia, nas empresas, na cultura.
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Dissertation presented to obtain the Ph.D degree in Evolutionary Biology
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Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Gestão de Informação
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics
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Dissertação para obtenção do Grau de Mestre em Engenharia Mecânica
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics