986 resultados para moment fletor


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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O presente trabalho trata da formulação e da implementação computacional, em MATLAB®, para a análise numérica de seções reforçadas de concreto armado, submetidas à flexão composta, considerando o estado de tensões anterior ao reforço. A referida análise se dá com a geração de diagramas de interação momento fletor esforço normal por dois métodos, quais sejam: a) varredura dos domínios de deformação da NBR6118/2003; b) determinação dos picos de diagramas momento fletor – esforço normal – curvatura. Em ambos os procedimentos utiliza-se o método numérico do ponto médio na integração do cálculo dos esforços resistentes, e o método de Newton Raphson para a obtenção de raízes é usado na determinação da deformação no eixo de referência da seção, durante a determinação dos diagramas momento fletor -esforço normal - curvatura. Preliminarmente, concluiu-se que a primeira das duas metodologias aplicadas é inviável. Posteriormente, com a confirmação da eficácia da segunda metodologia, foi possível expandir o escopo do trabalho de modo a permitir a análise de seções de formatos quaisquer executadas em várias etapas, considerando o estado de tensões inicial em cada uma das etapas. A implementação computacional referente a este trabalho se baseou no programa para análise numérica de seções SECLAB, desenvolvido pelo professor Remo Magalhães de Souza.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Structure is the resistant part of a construction that is able to support forces and transmit them to its supports or links. Knowing its importance, it is necessary to do a structural analysis. This study focuses on showing, in a different way, a method of understanding the bending moment and the shear beam diagrams. A real model was developed in laboratory to check what happens when certain loads are placed along. Throughout this study it was possible to verify that the practical application of the theory will provide the classroom a better understanding

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Engenharia Mecânica - FEG

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Background: Cardiovascular disease is an important cause of death in patients on dialysis. Peripheral arterial disease (PAD) is a prognostic factor for cardiovascular disease. The ankle brachial index (ABI) is a noninvasive method used for the diagnosis of PAD. The difference between ABI pre- and post-dialysis had not yet been formally tested, and it was the main objective of this study. Methods:The ABI was assessed using an automated oscillometric device in incident patients on hemodialysis. All blood pressure readings were taken in triplicate pre- and post-dialysis in three consecutive dialysis sessions (times 1, 2, and 3). Results: One hundred and twenty-three patients (85 men) aged 53 +/- 19 years were enrolled. We found no difference in ABI pre- and post-dialysis on the right or left side, and there was no difference in times 1, 2, and 3. In patients with a history of PAD, the ABI pre- versus post-dialysis were of borderline significance on the right side (p = 0.088). Conclusion: ABI measured pre- and post-dialysis presented low variability. The ABI in patients with a history of PAD should be evaluated with caution. The applicability of the current method in predicting mortality among patients on hemodialysis therefore needs further investigation. Copyright (C) 2012 S. Karger AG, Basel

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Upper bounds on fundamental length are discussed that follow from the fact that a magnetic moment is inherent in a charged particle in noncommutative (NC) electrodynamics. The strongest result thus obtained for the fundamental length is still larger than the estimate of electron or muon size achieved following the Brodsky-Drell and Dehlmet approach to lepton compositeness. This means that NC electrodynamics cannot alone explain the whole existing discrepancy between the theoretical and experimental values of the muon magnetic moment. On the contrary, as measurements and calculations are further improved, the fundamental length estimate based on electron data may go down to match its compositeness radius.

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We study a strongly interacting "quantum dot 1" and a weakly interacting "dot 2" connected in parallel to metallic leads. Gate voltages can drive the system between Kondo-quenched and non-Kondo free-moment phases separated by Kosterlitz-Thouless quantum phase transitions. Away from the immediate vicinity of the quantum phase transitions, the physical properties retain signatures of first-order transitions found previously to arise when dot 2 is strictly noninteracting. As interactions in dot 2 become stronger relative to the dot-lead coupling, the free moment in the non-Kondo phase evolves smoothly from an isolated spin-one-half in dot 1 to a many-body doublet arising from the incomplete Kondo compensation by the leads of a combined dot spin-one. These limits, which feature very different spin correlations between dot and lead electrons, can be distinguished by weak-bias conductance measurements performed at finite temperatures.

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The molecular method is used to obtain nuclear electric quadrupole moment (NQM) values for hafnium through electric field gradients (EFGs) at this nucleus in HfO and HfS. Dirac-Coulomb calculations with the Coupled Cluster approach, DC-CCSD (T) and DC-CCSD-T, were carried out to achieve the most accurate estimates of these EFGs. Higher order corrections are also added. Hence, the most reliable values for 177Hf and 179Hf determined here are 3319(33) and 3750(37) mbarn, respectively, in nice accordance with the best currently accepted NQMs for this element. (C) 2012 Elsevier B.V. All rights reserved.

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Study design: Experimental, controlled, animal study. Objectives: To evaluate the functional effect of hyperbaric oxygen therapy administered shortly, one day after, and no intervention (control) in standardized experimental spinal cord lesions in Wistar rats. Setting: Sao Paulo, Brazil. Methods: In all, 30 Wistar rats with spinal cord lesions were divided into three groups: one group was submitted to hyperbaric oxygen therapy beginning half an hour after the lesion and with a total of 10 one-hour sessions, one session per day, at 2 atm; the second received the same treatment, but beginning on the day after the lesion; and the third received no treatment (control). The Basso, Beattie and Bresnahan scales were used for functional evaluation on the second day after the lesion and then weekly, until being killed 1 month later. Results: There were no significant differences between the groups in the functional analysis on the second day after the lesion. There was no functional difference comparing Groups 1 and 2 (treated shortly after or one day after) in any evaluation moment. On the 7th day, as well as on the 21st and 28th postoperative days, the evaluation showed that Groups 1 and 2 performed significantly better than the control group (receiving no therapy). Conclusion: Hyperbaric chamber therapy is beneficial in the functional recovery of spinal cord lesions in rats, if it is first administered just after spinal cord injury or within 24 h. Spinal Cord (2012) 50, 502-506; doi: 10.1038/sc.2012.16; published online 6 March 2012

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This research work faces the problem of insertion of viscous dampers into Moment Resisiting Frames (MRF) for maximum efficiency in mitigation of the seismic effects. The work would lead to a precise design indication. The fundamental result of the thesis consists in showing that, even for moment-resisting structures, you can design a system of added viscous dampers able to achieve target levels of performances. Ie given the reduction factor in the seismic response, discover the characteristics of the viscous dampers which allow to achieve it.

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By using a symbolic method, known in the literature as the classical umbral calculus, a symbolic representation of Lévy processes is given and a new family of time-space harmonic polynomials with respect to such processes, which includes and generalizes the exponential complete Bell polynomials, is introduced. The usefulness of time-space harmonic polynomials with respect to Lévy processes is that it is a martingale the stochastic process obtained by replacing the indeterminate x of the polynomials with a Lévy process, whereas the Lévy process does not necessarily have this property. Therefore to find such polynomials could be particularly meaningful for applications. This new family includes Hermite polynomials, time-space harmonic with respect to Brownian motion, Poisson-Charlier polynomials with respect to Poisson processes, Laguerre and actuarial polynomials with respect to Gamma processes , Meixner polynomials of the first kind with respect to Pascal processes, Euler, Bernoulli, Krawtchuk, and pseudo-Narumi polynomials with respect to suitable random walks. The role played by cumulants is stressed and brought to the light, either in the symbolic representation of Lévy processes and their infinite divisibility property, either in the generalization, via umbral Kailath-Segall formula, of the well-known formulae giving elementary symmetric polynomials in terms of power sum symmetric polynomials. The expression of the family of time-space harmonic polynomials here introduced has some connections with the so-called moment representation of various families of multivariate polynomials. Such moment representation has been studied here for the first time in connection with the time-space harmonic property with respect to suitable symbolic multivariate Lévy processes. In particular, multivariate Hermite polynomials and their properties have been studied in connection with a symbolic version of the multivariate Brownian motion, while multivariate Bernoulli and Euler polynomials are represented as powers of multivariate polynomials which are time-space harmonic with respect to suitable multivariate Lévy processes.