151 resultados para Campos magneticos

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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

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Pós-graduação em Ciência e Tecnologia de Materiais - FC

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The main idea of this work is to understand and analyze the dynamical aspects of the motion of a particle moving in the annular billiard, which corresponds to two circles of radius R and r (r

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Pós-graduação em Engenharia Elétrica - FEIS

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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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Magnetic fields can be produced by natural magnets, artificial magnets, and by circulating electric currents in wires and solenoids. An interesting experiment to observe the interaction between the magnetic field and free charges in a conductor, a magnet falling inside a tube made of conductive materials. The slowing down of the magnet by the appearance of a field in the opposite direction to the original one (Lenz's Law) is function the number of free electrons in the conductor and the electrical properties of this. Based on this, the objective of this study is to analyze the relationship between the electrical properties of conductors, copper and aluminum, with magnetic force on a neodymium magnet-iron-boron magnet falling inside a copper tube and aluminum, positioned vertically. In performing this experiment, we observed that it is a demonstration of Lenz-Faraday’s Law

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This work will discuss how magnetic fields can be produced, either generated by magnets, natural, artificial, or even by an electric current going through a wire, as discovered by Oersted. Besides the theoretical content, experimental studies on magnetic induction and on the Laws of Faraday and Lenz will be performed. In the Magnetic Induction experiment, the electromotive force generated by varying the flow of the field B in a solenoid, depending on the variation of the current intensity and frequency associated with it will be measured; the experiment on the Laws of Faraday and Lenz the electromotive force produced by the relative movement of the magnet in relation to a coil. Thus, this study experimental verification of magnetic induction using solenoids and magnets; analysis of magnetic induction by Faraday's Law and Lenz's Law

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Magnetic resonance imaging (MRI), which is studied since 1938, is a technique used in medicine to produce high quality images from inside the human body. These images are produced non-invasively and without ionizing radiation. In addition, MRI is an extremely flexible technique, with which it is possible to produce images with different contrasts that provide different information about the anatomy, structure and function of the human body, and it is therefore one of the techniques preferred by radiologists. The phenomenon of MRI is based on the interaction of magnetic fields with the nuclear spins of the scanned sample. In this work a detailed study of the technique of magnetic resonance imaging is presented, with a description of the main features of the images produced by the technique and an analysis of its application to the fields of applications Neurology and Neuroscience

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This paper proposes a methodology for automatic extraction of building roof contours from a Digital Elevation Model (DEM), which is generated through the regularization of an available laser point cloud. The methodology is based on two steps. First, in order to detect high objects (buildings, trees etc.), the DEM is segmented through a recursive splitting technique and a Bayesian merging technique. The recursive splitting technique uses the quadtree structure for subdividing the DEM into homogeneous regions. In order to minimize the fragmentation, which is commonly observed in the results of the recursive splitting segmentation, a region merging technique based on the Bayesian framework is applied to the previously segmented data. The high object polygons are extracted by using vectorization and polygonization techniques. Second, the building roof contours are identified among all high objects extracted previously. Taking into account some roof properties and some feature measurements (e. g., area, rectangularity, and angles between principal axes of the roofs), an energy function was developed based on the Markov Random Field (MRF) model. The solution of this function is a polygon set corresponding to building roof contours and is found by using a minimization technique, like the Simulated Annealing (SA) algorithm. Experiments carried out with laser scanning DEM's showed that the methodology works properly, as it delivered roof contours with approximately 90% shape accuracy and no false positive was verified.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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OBJETIVO: O objetivo do estudo foi descrever os casos de fissuras labiopalatais registrados na AAFLAP (Associação de Apoio aos Fissurados Labiopalatais), ocorridos na cidade de São José dos Campos - SP, em relação ao sexo, classificação socioeconômica, tipo de fissura e concomitância com síndromes. MÉTODOS: Os dados foram levantados das fichas preenchidas pela AAFLAP, entidade que recebe, orienta e encaminha para a realização dos procedimentos terapêuticos necessários, totalizando 200 crianças acometidas no período de 1992 a 2002. RESULTADOS: da análise dos dados pode-se observar que não houve diferença significativa na ocorrência de fissuras labiopalatais com relação ao sexo, sendo 48% do feminino e 52% do masculino, e que 73,70% dos casos acometeram crianças oriundas de classe socioeconômica desfavorecida. A fissura do tipo pós-forame incisivo prevaleceu em 41,33% dos casos, seguida da transforame incisivo com 33,16%, da pré-forame incisivo com 24,49% e das raras com 1,02%. Dos casos de fissura pós-forame incisivo, a incompleta totalizou 79%; dos casos de fissura pré-forame incisivo, o lado esquerdo totalizou 56% dos casos. de todos os casos levantados de fissuras labiopalatais, 9,18% estavam associados a alguma síndrome, sendo a Síndrome de Pierre Robin a mais prevalente e, em 94% das vezes, associada ao tipo de fissura pós-forame incisivo incompleta. CONCLUSÃO: Não houve diferença na ocorrência com relação ao sexo da criança; a classe socioeconômica desfavorecida foi a mais acometida; a fissura mais prevalente foi a pós-forame incompleta, e um décimo do total estudado, aproximadamente, apresentava associação com alguma síndrome.