155 resultados para Reduced physical models
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Recently, a group of researchers proposed the concept of entransy by analogy with the electrical energy stored in a capacitor, the entransy being a measure of the ability of a body or a system to transfer heat. In comparative terms, the entransy dissipation rate is related with the loss of heat transfer ability just like the exergy destruction rate is proportional to the loss of work ability, being these losses caused by the irreversibilities related to the thermodynamic processes. Some authors have questioned the need for the concept of entransy, claiming that this concept is only an extension of a well established theory of heat transfer. The objective of this work is show the equivalence between the application of the concepts of entransy and entropy generation rate, which can be verified using various application examples. The application examples used here are the thermodynamic modeling of three physical models of solar energy collectors and a physical model of a sensible heat storage system. Analytical results are shown and compared. The results showed that the application of the concept of entransy provided identical expressions obtained by the concept of entropy generation, indicating a duplication of concepts. (C) 2014 Elsevier Ltd. All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The huge demand for procedures involving ionizing radiation promotes the need for safe methods of experimentation considering the danger of their biological e ects with consequent risk to humans. Brazilian's legislation prohibits experiments involving this type of radiation in humans through Decree 453 of Ministry of Health with determines that such procedures comply with the principles of justi cation, optimization and dose limitation. In this line, concurrently with the advancement of available computer processing power, computing simulations have become relevant in those situations where experimental procedures are too cost or impractical. The Monte Carlo method, created along the Manhattan Project duringWorldWar II, is a powerful strategy to simulations in computational physics. In medical physics, this technique has been extensively used with applications in diagnostics and cancer treatment. The objective of this work is to simulate the production and detection of X-rays for the energy range of diagnostic radiology, for molybdenum target, using the Geant4 toolkit. X-ray tubes with this kind of target material are used in diagnostic radiology, speci cally in mammography, one of the most used techniques for screening of breast cancer in women. During the simulations, we used di erent models for bremsstrahlung available in physical models for low energy, in situations already covered by the literature in earlier versions of Geant4. Our results show that although the physical situations seems qualitatively adequate, quantitative comparisons to available analytical data shows aws in the code of Geant4 Low Energy source
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Physics governs all working patterns of the universe and could not be otherwise in a biological environment. Living things depend directly on laws and physical models to compose their body structure, allow its survival in certain environments, communication between individuals and groups and also to establish a complex sensorial system that allows interaction with the environment that surrounds them. With the advancement of science and technology, new ideas are required, and thus, many researchers began to turn their attention to those systems found in nature, as these systems often present practical solutions and with maximum efficiency. This imitation of biological systems, applied in creating innovative technological resources, is called Biomimetics. To study the biological systems based on physical concepts is essential the creation of models. These allow the distinction of the effects of the issue really essential and may be ignored side effects that do not have an effective participation in the phenomenon being analyzed. In this Work Completion of course will be studied the phenomenon of countercurrent heat exchangers, present in various situations of nature, focusing on their participation in the legs of birds, also the balance of certain birds that are supported on one leg and possible inspiration of these phenomena in the fields of engineering. Also included are videos that allow better understanding of the studied subjects
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There are considerations of that the education of Physics of the way as comes being driven us textbooks and consequently in classroom, is distant and distorted of their real purpose. We notice that the education of this science through the Physical school discipline, has I assume a character of preparation for university entrance exams exercises resolution, exceling for the memorization of formulae and by the mathematical solutions, fact that looks to cause to it is lacking of motivation and to the disinterest of the students regarding his contents. Since we are surrounded by phenomena, events, elements of the nature, new technologies, objects and so many others that can be explained and many times until applied and/or reproduced by means of physical concepts, there is no reason for treat to Physical as somewhat academic and remote of the reality. The little interest of high school students by the discipline of Physics and their poor performance in the learning of his contents has led to the search of new paths, resources and strategies that promote a more meaningful learning. Taking into account these facts, we seek in this course conclusion work, observe, analyze and apply concepts of the Physical one in multiple elements of ours routine, doing use of the interdisciplinary nature as a possible mechanism. The animals exert a fascination on most people. Much of what we see in their way of being and behaving can be explained by the laws of Physics and its models. Their physique, behavior and activities involve diverse movements, communication and sensing as physical limitations varied. Zoologists and physicists build models in an attempt to explain or understand animal behavior using well-established physical principles. The creation of physical models is going to approach a problem, identifies the fundamental information and removing all of the irrelevant details. An example... (Complete abstract click electrnic access below)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Esta pesquisa foi conduzida com o objetivo de avaliar diferentes tipos de coberturas em instalações para aves, por meio do Índice de Temperatura de Globo Negro e Umidade (ITGU), Carga Térmica de Radiação (CTR) e Entalpia (H). O experimento foi conduzido na Universidade Estadual de Goiás, entre os meses de abril e maio de 2011, sendo composto por cinco tratamentos (coberturas): CA -Telha de cimento-amianto; BA -Telha de bambu; BAP -Telha de bambu pintada de branco; FB -Telha de fibra vegetal e betume; FBP -Telha de fibra vegetal e betume pintada de branco, com 15 repetições, sendo as repetições os dias de medição. Dentre os horários estudados, o considerado menos confortável foi às 14h, sendo que a cobertura de fibra vegetal e betume foi a que apresentou maior valor de ITGU (84,1) quando comparada às demais coberturas, caracterizando uma situação de menor conforto térmico, não sendo observada diferença para CTR e H entre os tratamentos na região estudada.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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We demonstrate that the generating functionals for two-dimensional models with two real scalar fields, one interacting with an external electromagnetic field and the other with coupling terms but without external fields, can be reduced to the case of the free-particle propagator when quasistatic solutions for this theory are used. © 1991 The American Physical Society.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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We study the production and signatures of doubly charged Higgs bosons (DCHBs) in the process gamma gamma <-> H(--)H(++) at the e(-)e(+) International Linear Collider and CERN Linear Collider, where the intermediate photons are given by the Weizsacker-Willians and laser backscattering distributions.