Scalar Fields
Mostrando 1-12 de 49 artigos, teses e dissertações.
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1. Two-Dimensional Numerical Model of the Fracture Process in Steel Fibre Reinforced Concrete with the Continuum Strong Discontinuity Approach and Functional Data Analysis
Abstract This paper presents the formulation of a two-dimensional numeri-cal model able to describe the fracture process in structural mem-bers of steel fibre reinforced concrete (SFRC) from the volume ratio of the fibres and the mechanical properties of the compo-nents: a concrete matrix and a set of steel fibres with a random orientation. The relationship
Lat. Am. j. solids struct.. Publicado em: 08/04/2019
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2. An Improved Method for Acquisition of the Parameters of Jiles-Atherton Hysteresis Scalar Model Using Integral Calculus
Abstract An accurate modeling of materials is essential to obtain reliable results in fields calculation. The Jiles-Atherton approach is widely used for modeling the magnetic hysteresis and depends on its set of five parameters to properly represent material. In this article is proposed an original methodology for obtaining this set of parameters avoiding th
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
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3. Rigidez de superfÃcies de contato e caracterizaÃÃo de variedades riemannianas munidas de um campo conforme ou de alguma mÃtrica especial / Rigidity of the contact surfaces and characterization of Riemannian manifolds carrying a conformal vector fields or some special metric
Esta tese està composta de quatro partes distintas. Na primeira parte, vamos dar uma nova caracterizaÃÃo da esfera euclidiana como a Ãnica variedade Riemanniana compacta com curvatura escalar constante e admitindo um campo de vetores conforme nÃo trivial que à tambÃm Ricci conforme. Na segunda parte, provaremos algumas propriedades dos quase sÃlitons
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/06/2012
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4. Modelos Gêmeos em Teorias de Campos Escalares
No presente trabalho fazemos uma investigação de novas características dos chamados kdefeitos, que são defeitos topológicos com termo cinético não-canônico. Especificamente, estudamos uma classe de k-defeitos em modelos de teorias de campos escalares distintos da teoria padrão mas que descrevem, caso a caso, o mesmo defeito com a mesma densidade de
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/03/2012
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5. Os elementos finitos no estudo de eletromagnetismo utilizando os Software Gmsh/GetDP / The finite element method in electromagnetics study using the software Gmsh/GetDP
The aim of this master thesis is to study and develop two-dimensional and three-dimensional mathematical models, taking into account Maxwell s equations, the laws of material behavior and boundary conditions. Moreover, have discretization fields by finite element method using the Galerkin approach for electromagnetic analysis, and particularly problems of el
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/02/2012
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6. Tópicos em cosmologia com campos escalares
Modelos cosmológicos envolvendo campos escalares permitem a descrição de uma fase de expansão cósmica acelerada e, portanto, se apresentam como uma alternativa promissora no estudo da inflação cósmica e da energia escura. Estamos aqui interessados em analisar esses modelos cosmológicos; em especial, vamos explorar soluções cosmológicas baseadas n
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 20/05/2011
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7. Effects of spontaneous symmetry breaking-CPT and Lorentz invariance of the phenomenon the Bose-Einstein / Efeitos da quebra espontânea da simetria-CPT e da invariância de Lorentz no fenômeno da condensação de Bose-Einstein
The Bose-Einstein condensate (BEC), also known as the fifth state of the matter, was predicted theoretically by Albert Einstein in 1925 and verified experimentally 70 years later in 1995. This dissertation addresses the effects of spontaneous broken of the CPT-symmetry and of the invariance Lorentz (also called simply the violation of Lorentz symmetry) in th
Publicado em: 2011
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8. Effective cosmology a la Brans-Dicke with a non-minimally coupling massive inflaton field interacting with minimally coupling massless field
We discuss an effective cosmology a la Brans-Dicke with two interacting scalar fields: a non-minimally coupling massive inflaton Higgs-like scalar field Φ interacting with a minimally coupling massless scalar field χ. Several features are observed and discussed in some details.
Brazilian Journal of Physics. Publicado em: 2010-09
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9. Vacuum energies and multipole interactions
In this paper, we present a quantum-field-theoretical description of the interaction between stationary and localized external sources linearly coupled to bosonic fields (specifically, we study models with a scalar and the Maxwell field). We consider external sources that simulate not only point charges but also higher-multipole distributions along D-dimensi
Brazilian Journal of Physics. Publicado em: 2010-06
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10. Efeitos cosmológicos induzidos por campos quantizados / Cosmological effects induced by quantized fields
The present dissertation reviews the coupling of a scalar non-interacting quantum field with the metric of a FLRW(Friedmann-Lemaítre-Robertson-Walker) spacetime, proposed in a work by C. Dappiaggi, K. Fredenhagen and N. Pinamonti. We present methods for the quantization of a real Klein-Gordon field in globally hyperbolic spacetimes and discuss procedures fo
Publicado em: 2010
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11. Berry's phase in the two-level model
We study the adiabatic evolution of a two-level model in the presence of an external classical electric field. The coupling between the quantum model and the classical field is taken in the electric dipole approximation. In this regime, we show the absence of geometric phases in the interacting two-level model in the presence of any periodic real time-depend
Brazilian Journal of Physics. Publicado em: 2009-06
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12. Sobre alguns efeitos quânticos no espaço-tempo de Schwarzschild-de Sitter
In this dissertation we investigate some aspects related with normal modes for scalar fields perturbations of a Schwarzshild-de Sitter black hole. The role played by the cosmological constant A on the reflection and transmission coefficients is studied and analyzed. We also study the Casimir energy density for a massless scalar field confined between two nea
Publicado em: 2009