Global ETD Search

1	Não-linearidade física e geométrica no projeto de edifícios usuais de concreto armado / Physical and geometrical non-linearity in design of usual reinforced concrete buildings Pinto, Rivelli da Silva 26 April 1997 (has links) Neste trabalho são discutidos os procedimentos simplificados para a consideração da não linearidade física (NLF) e da não linearidade geométrica (NLG) na análise de edifícios de concreto armado. Deste modo, pretende-se estabelecer o grau de confiabilidade desses processos. Algumas prescrições para redução na inércia dos elementos estruturais são comparadas com os resultados obtidos através de modelos em elementos finitos, permitindo, assim, a avaliação destas prescrições. Um estudo detalhado do parâmetro &#947z, como majorador dos esforços em primeira ordem para a obtenção dos esforços finais em segunda ordem, é efetuada, de modo que se possa estabelecer, de forma mais clara, as vantagens e as limitações deste parâmetro. / This work shows some simplified procedures to consider physical non-linearity (FNL) and geometrical non-linearity (GNL), for reinforced concrete buildings, and discusses its reliability. For FNL, prescriptions for stiffness reduction of structural elements are compared with the results obtained from finite elements analysis, in order to verify its assessment. For GNL, a detailed study of the accuracy of &#947z parameter to evaluate final second order effects is made. The behavior of the parameter along the height of the building and for each effort considered is shown. Edifícios altos Efeitos de segunda ordem Geometrical non-linearity (GNL) Instability parameters Não-linearidade física (NLF) Não-linearidade geométrica (NLG) Parâmetros de instabilidade Physical non-linearity (FNL) Second order effects Tall buildings
2	Developments for a Swept Wing Airfoil to Study the Effects of Step and Gap Excrescences on Boundary Layer Transition Hedderman, Simon Peter 02 October 2013 (has links) Skin friction drag reduction is one of the most promising paths in the investigation of the reduction of aircraft fuel burn. 40 – 50% of overall drag comes from the surfaces of the wings and stabilizers. Natural laminar flow airfoils can extend the region of laminar flow and reduce skin friction drag. However, real-world aircraft wings do not have perfectly smooth surfaces, and therefore the tolerances for step and gap excrescences on these airfoils must be investigated. Previous work has focused on excrescences on flat plates, and only recently included pressure gradient effects. A new three-dimensional swept wing airfoil with an actuated leading edge (SWIFTER) has been constructed, and will extend the body of knowledge of step and gap excrescences to a more real-world configuration and higher Reynolds numbers. An integrated control system for the leading edge actuation system is proposed, including both interface hardware and control code. A heating system for the test surface is also discussed, and the controller hardware, sensors, and code specified. For wind tunnel testing, a proposed set of wall liners are developed from zero-lift condition streamlines and divided into parts suitable for manufacturing, assembly, and installation. Finally, preliminary wind tunnel step excrescence tests using an existing swept-wing model and applique step material were conducted, and the results are discussed with relevance to testing on the new model. boundary layer stability excrescence excrescences SWIFT SWIFTER step gap airfoil swept wing actuation control system heating sheet wind tunnel wall liners natural laminar flow nlf
3	Não-linearidade física e geométrica no projeto de edifícios usuais de concreto armado / Physical and geometrical non-linearity in design of usual reinforced concrete buildings Rivelli da Silva Pinto 26 April 1997 (has links) Neste trabalho são discutidos os procedimentos simplificados para a consideração da não linearidade física (NLF) e da não linearidade geométrica (NLG) na análise de edifícios de concreto armado. Deste modo, pretende-se estabelecer o grau de confiabilidade desses processos. Algumas prescrições para redução na inércia dos elementos estruturais são comparadas com os resultados obtidos através de modelos em elementos finitos, permitindo, assim, a avaliação destas prescrições. Um estudo detalhado do parâmetro &#947z, como majorador dos esforços em primeira ordem para a obtenção dos esforços finais em segunda ordem, é efetuada, de modo que se possa estabelecer, de forma mais clara, as vantagens e as limitações deste parâmetro. / This work shows some simplified procedures to consider physical non-linearity (FNL) and geometrical non-linearity (GNL), for reinforced concrete buildings, and discusses its reliability. For FNL, prescriptions for stiffness reduction of structural elements are compared with the results obtained from finite elements analysis, in order to verify its assessment. For GNL, a detailed study of the accuracy of &#947z parameter to evaluate final second order effects is made. The behavior of the parameter along the height of the building and for each effort considered is shown. Edifícios altos Efeitos de segunda ordem Não-linearidade física (NLF) Não-linearidade geométrica (NLG) Parâmetros de instabilidade Geometrical non-linearity (GNL) Instability parameters Physical non-linearity (FNL) Second order effects Tall buildings
4	Between Interest and Interventionism : Probing the Limits of Foreign Policy along the Tracks of an Extraordinary Case Study : The GDR's Engagement in South Yemen Muller, Miriam Manuela 13 March 2015 (has links) This case study is the first comprehensive analysis of the German Democratic Republic’s activities in South Yemen, the only Marxist state in the Arab World and at times the closest and most loyal ally to the Soviet Union in the Middle East during the Cold War. The dissertation analyzes East German Foreign Policy as a case of Socialist state- and nation-building and in doing so produces one major hypotheses: The case of South Yemen may be considered both, an ‘exceptional case’ and the possible ‘ideal type’ of the ‘general’ of East German foreign policy and thus points to what the GDR’s foreign policy could have been, if it hadn’t been for the numerous restraints of East German foreign-policy-making. The author critically engages with the normative and empirical dimensions of the ‘Limits of Foreign Policy’ by including a constructivist perspective of foreign policy. Apart from the case study itself, the dissertation provides the reader with a thorough overview of forty years of East German foreign policy with a focus on the interests and influence of The Soviet Union as well as the first introduction and methodological approach to East Germany's foreign policy in the Middle East. The empirical side of the analysis rests on archival documents of the German Foreign Office, the German National Archive and the former Ministry of State Security of the GDR. These documents are reviewed and published for the first time and are complemented by personal interviews with contemporary witnesses. The interdisciplinary approach integrates and expands methods of both History and Political Science, applicable to other cases. Conducted research is intended to contribute to academic discourse on South Yemen’s unique history, divided Germany’s role in the Cold War, East German foreign policy, but also the long-term impact of Socialist foreign-policy-making in the Global South which so far has been neglected almost completely in academia. / Graduate / miriam.mueller@fu-berlin.de South Yemen PDRY GDR Foreign Policy Divided Germany Cold War Soviet Union Socialism State-Building Nation-Building Gulf of Aden Crown Colony of Aden British Occupation National Liberation Front Marxism-Leninism Postcolonialism Neocolonialism German Identity Arab Nationalism Arab Socialism Arab Nationalist Movement Al-Hirak Southern Movement Constructivism Socialist Development Global South Middle East Arab Spring Marxist Critical Bab Al-Mandab Socotra Yemeni Socialist Party YSP FLOSY National Liberation Front NLF SED Honecker Ulbricht East Berlin

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