Constant Curvature
Mostrando 1-12 de 119 artigos, teses e dissertações.
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1. Hidrodinâmica relativística: a representação de diversos fluidos em relatividade geral
Resumo O tensor de momento-energia é a entidade matemática que representa de forma unificada as fontes de momento e energia no formalismo covariante, tanto em espaços planos, como em espaços curvos. Em espaços curvos o tensor de momento-energia fica conectado a curvatura do espaço-tempo via equação de campo de Einstein. O tensor de momento-energia ca
Rev. Bras. Ensino Fís.. Publicado em: 04/11/2019
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2. Microscopía fototérmica para el estudio de transformaciones de fase
ABSTRACT A novel system allowing a high spatial resolution mapping of the thermal diffusivity as a function of temperature up to 1800 K is presented. The system is based on a photothermal technique recently developed by the group, consisting in measuring, with a probe laser beam, the curvature induced by local heating with a modulated pump laser. A microscop
Matéria (Rio J.). Publicado em: 19/07/2018
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3. Comparing the Performance of Ground Filtering Algorithms for Terrain Modeling in a Forest Environment Using Airborne LiDAR Data
ABSTRACT The aim of this study was to evaluate the performance of four ground filtering algorithms to generate digital terrain models (DTMs) from airborne light detection and ranging (LiDAR) data. The study area is a forest environment located in Washington state, USA with distinct classes of land use and land cover (e.g., shrubland, grassland, bare soil, an
Floresta Ambient.. Publicado em: 01/02/2018
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4. Translation Hypersurfaces with Constant Sr Curvature in the Euclidean Space
Abstract The main goal of this paper is to present a complete description of all translation hypersurfaces with constant r-curvature S r, in the Euclidean space ℝ n + 1, where 3 ≤ r ≤ n - 1.
An. Acad. Bras. Ciênc.. Publicado em: 01/12/2016
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5. Construction of a Morphing Wing Rib Actuated by a NiTi Wire
ABSTRACT: The main goal of this paper is to analyze if it is feasible to employ a trained shape memory alloy wire as a linear actuator to modify the camber of a morphing wing rib. In order to achieve this purpose, a morphing rib with a compliant trailing edge was proposed, developed, and subjected to structural analyses to ensure its flexibility. After the r
J. Aerosp. Technol. Manag.. Publicado em: 2015-12
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6. Effects of temperature-dependent viscosity on fluid flow and heat transfer in a helical rectangular duct with a finite pitch
An incompressible fully developed laminar flow in a helical rectangular duct having finite pitch and curvature with temperature-dependent viscosity under heating condition is studied in this work. Both the cases of one wall heated and four walls heated are studied. The cross-sectional dimensions of the rectangular duct are 2a and 2b. The aspect ratio n=2b/2a
Braz. J. Chem. Eng.. Publicado em: 2014-09
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7. Simulação computacional, projeto, construção e análise do desempenho de uma matriz para extrusão em canal angular dedicada ao processamento de chapas / Computational simulation, design, construction and performance analysis of an equal channel angular pressing die for the processing of flat billets
The present work describes the design, construction and testing of an equal channel angular pressing (ECAP) die characterized by rectangular cross section channels. The main parameter of the ECAP dies is the geometry of the channels, given by the angle trough which they meet, and the curvature radii at this point. The material employed in the experiments was
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/08/2012
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8. 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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9. Sobre teorema de comparaÃÃo de autovalores de Cheng / On Cheng s eigenvalue comparison theorem
We present a version of Chengâs Eigenvalue Comparison Theorem, where the limitation of the sectional and Ricci curvature is changed by limiting the mean curvature of the ball away. Furthermore, the present construction of smooth metrics gk,in [0;r] x S3, non-isometric to the canonical metric of constant sectional curvature k, cank , such that the balls geod
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/04/2012
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10. Vórtices em superfícies de curvatura constante / Vortices on surfaces with constant curvature
Nesta dissertação, fazemos uma revisão da literatura existente sobre vórtices em superfícies de curvatura constante, dando especial atenção às questões de integrabilidade e não integrabilidade. Além disso, apresentamos alguns resultados originais sobre o movimento de vórtices no plano hiperbólico que indicam um possível caminho para demonstrar
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 15/03/2012
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11. Variedades com curvatura prescrita : resultados de existÃncia, unicidade, rigidez e bifurcaÃÃo / Manifolds with prescribe curvature: results of existence uniqueness, rigidity and bifurcation
We present several results of existence, uniqueness, rigidity and bifurcation for the problem of prescribing various geometric structures on Riemannian manifolds, among which include: i) deformation and rigidity for 2k-Einstein structures on manifolds with constant (2k − 2)-sectional curvature; ii) conformal deformation of metrics in the context of the
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/02/2012
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12. Sobre rigidez de hipersuperfÃcies completas / On rigidity of complete hypersurfaces
The purpose of this thesis is to obtain characterization theorems of complete spacelike hypersurfaces isometrically immersed in a semi-Riemannian ambient space under some restrictions on the Gauss mapping or about the r-mean curvatures of these objects. We start our work by providing necessary conditions to ensure the umbilicity of immersed hypersurfaces in
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/08/2011