Conductors
Mostrando 13-24 de 86 artigos, teses e dissertações.
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13. Avaliação de sistemas de aterramento considerando a utilização de condutores e hastes envolvidos em concreto / Evaluation of grounding systems considering the use of conductors and rods encased in concrete
O aterramento elétrico cumpre uma função essencial em um sistema de distribuição de energia elétrica, devendo atender, dentre vários requisitos, aqueles estabelecidos quanto aos valores de tensão de passo e de toque. Entretanto, em locais onde o solo apresenta valores elevados de resistividade, surgem dificuldades que nem sempre são superadas no sen
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/06/2011
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14. Las cargas y los campos que rodean un circuito y los ejemplos de J.H. Poynting sobre la transferencia de energía electromagnética
We review two examples on the transport of energy in DC circuits proposed by J.H. Poynting in 1884: a straight wire carrying a current and a capacitor discharge through a wire. In particular we analyze whether some of the Poynting hypothesis in these examples are due to at that time was unaware the role of surface charge on the resistive conductors in the un
Revista Brasileira de Ensino de Física. Publicado em: 2011-03
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15. Properties and applications of perovskite proton conductors
A brief overview is given of the main types and principles of solid-state proton conductors with perovskite structure. Their properties are summarized in terms of the defect chemistry, proton transport and chemical stability. A good understanding of these subjects allows the manufacturing of compounds with the desired electrical properties, for application i
Materials Research. Publicado em: 2010-09
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16. Dimensionamento de barramentos em subestações
Este trabalho visa conceituar barramentos em subestações e apresentar uma sistemática para escolha e dimensionamento desses condutores. Para atingir esse objetivo, foram estudados os métodos comumente utilizados de dimensionamento. Este dimensionamento é dividido segundo os critérios elétrico, térmico, mecânico e de efeito corona. Este documento é
Publicado em: 2010
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17. A proposal for optimized analysis of transient currents in conductive materials. / Uma proposta para análise otimizada de correntes transitórias em materiais condutores.
In this work, a methodology is developed, based on the application of the moment method associated to a finite difference approximation, for time domain analysis of transient current distribution in conducting media. The computational procedure allows that long conductors with any cross section can be considered, approximated by filamentary elements. Thus, t
Publicado em: 2010
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18. Sight-singing : a way for the construction of audiation for the professional musician / Leitura cantada : um caminho para construção da audiação no músico profissional
This research is an exploratory study of qualitative nature, and aims to examine the relevance of sight-singing and audiation in the life of a professional musician. Initially, two possible views are presented for the study of sight-singing: historical and psychological. The former comprises a summarized historical review of the systematization of traditiona
Publicado em: 2010
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19. Aplicações de arranjos de antenas de microfita com patch supercondutor
This work has as main objective the study of arrays of microstrip antennas with superconductor rectangular patch. The phases and the radiation patterns are analyzed. A study of the main theories is presented that explain the microscopic and macroscopic phenomena of superconductivity. The BCS, London equations and the Two Fluid Model, are theories used in the
Publicado em: 2010
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20. Elements of a poetics of science: theoretical foundations and implications for science teaching. / Elementos de uma poética da ciência: fundamentos teóricos e implicações para o ensino de ciências
The objective of this thesis is to discuss the role of narrative in scientific thought and science education. We start from a historical review of research on teaching and learning to show that the epistemological dimension of the construction of knowledge rather than weakens the deeper understanding of the semiotic and discursive aspects of the interactions
Publicado em: 2010
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21. Espectroscopia Vibracional e de ImpedÃncia de A1-xAâxTaWO6.nH2O (A=H, Li, Aâ = Ag,H) / Espectroscopia Vibracional e de ImpedÃncia de A1-xAâxTaWO6.nH2O (A=H, Li, Aâ = Ag,H)
Realizamos a caracterizaÃÃo das amostras H1−x AgxTaWO6.H2O pirocloro e Hx Li1−xTaWO6 trirrutilo. TÃcnicas de espectroscopia Raman e transmitÃncia de infravermelho foram usadas com o objetivo de investigar propriedades estruturais do trirrutilo dopado. Os estudos revelaram que as amostras HxLi1−xTaWO6 pertencem ao sistema tetragonal pola
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/02/2009
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22. Critical indices of random planar electrical networks
We propose a new method to estimate the percolation threshold p c and the critical index t associated with strength reduction in networks of random fused conductors. It relies on a recently proposed expression for the yield strength of a network as a function of the probability p that each element is removed from it. The values of critical indices are confir
Brazilian Journal of Physics. Publicado em: 2009-06
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23. Ruido no transporte eletronico em sistemas mesoscopicos / Noise in the electronic transport in mesoscopic systems
This dissertation describes the fundamental caracteristics of mesoscopic conductors, and the origins and properties of the sources of noise in conductors. Firstly, we describe the noise through different methods and emphasize the properties of each kind of noise. In the following, we present the scattering approach for coherent phase conductors, which allows
Publicado em: 2009
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24. Técnicas de ensaio coral: reflexões sobre o ferramental do Maestro Carlos Alberto Pinto Fonseca
This research was conducted in view of the uniqueness and importance of Maestro Carlos Alberto Pinto Fonsecas work throughout his career as titular conductor of Ars Nova - Coral da UFMG. In order to contribute to the rescue of Brazils artistic and cultural memory and to fill many gaps in the technique universe in the area of Choral Conducting, the resources
Publicado em: 2009