Lagrangian Solutions
Mostrando 13-22 de 22 artigos, teses e dissertações.
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13. Weak stability of lagrangian solutions to the semigeostrophic equations / Estabilidade fraca de soluções lagrangeanas de equações semigeostroficas
As equações semigeostrocas, introduzidas por Hoskins e Bretherton em 1972 em [20], sao um conjunto de equacoes que modelam fluxos atmosfericos/ oceanicos de larga escala. Elas possuem uma formulação em variaveis duais que se presta ao tratamento analítico. Alguns autores estudaram esta formulação, veja, por exemplo, [3], [14], [22], [12], [21],em part
Publicado em: 2008
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14. Uma nova abordagem numérica para a injeção de traçadores em reservatórios de petróleo / A new numerical approach for the injection of tracers in petroleum reservoirs
The injection of tracers are used in the investigation of ows in heterogeneous porous media, in studies related to the simulation of miscible dispacements in petroleum reservoirs and the dispersion of contaminants in aquifers. In this work we present new algorithms for the numerical approximation of tracer injection problems. We discuss recent developments o
Publicado em: 2008
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15. Métodos numéricos euleriano-lagrangeanos para leis de conservação / Eulerian-lagrangina numeric methods for conservation laws
Este trabalho apresenta uma família de novos métodos numéricos euleriano-lagrangeanos localmente conservativos para leis de conservação hiperbólicas escalares. Estes métodos não utilizam soluções analíticas de problemas de Riemann e são bastante precisos na captura de saltos nas soluções. Estes métodos foram introduzidos, implementados computa
Publicado em: 2008
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16. Modelos constitutivos para materiais hiperelásticos: estudo e implementação computacional / Constitutive models for hyperelastic materials: study and computational implementation
The main objective of this work is to implement nonlinear hyperelastic constitutive models in a computational code of geometrically nonlinear analysis of shells. For this purpose, concepts of linear and tensor algebras, kinematics, strain, stress, balances, variational principles, numerical methods and hyperelasticity are necessary. Such program uses the pos
Publicado em: 2008
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17. Análise de um método para equação de convecção formulado à luz da mecânica dos meios contínuos a advecção de anomalias oceânicas e meteorológicas / Analysis of a method for the convection equation formulated in the light of mechanical means of the continuous advection of oceanic and meteorological anomalies
In the present work we studied and analyzed the Trajectories Tube method, a conservative, explicit, simple, physically intuitive, semi-Lagrangian algorithm for the convection equation. Kinematical aspects of the mechanics of continuous media are essentially the tools used for formulation and feasibility analysis. We showed that this method is unconditionally
Publicado em: 2006
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18. An heuiristic for the lot sizing problem in small market-driven foundries / Uma heurística para o problema de dimensionamento de lotes em fundições de mercado
The foundry sector is important to the economy as it produces basic components for many other sectors, to such an extent that its performance has a repercussion in other sectors. A recently published mixed integer-programming model for small market-driven foundries, which aims to minimize delays when delivering orders, was proposed in the literature. In this
Publicado em: 2006
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19. INVERSE PROBLEM IN ATMOSPHERIC PHISICS / PROBLEMAS INVERSOS EM FÍSICA DA ATMOSFERA
Techniques for estimating unknown terms - such as eddy diffusivity and counter-gradient - in atmospheric flow are presented in this study. The methos is also used to identify the source term in atmospheric pollution. The scheme adopted is based on inverse problem methodology. The inverse problem is formulated as a non-linear optimization problem, where the o
Publicado em: 2005
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20. Modelos Efetivos para o Elétron / Effective Models for the Electron
We present two models for the electron in classical electrodynamics, which include some effects from quantum electrodynamics. In the first model, the electron is treated as an extended particle owing to the high-frequency oscillations (Zitterbewegung) of its electrical charge. We show that this model predicts correctly the magnitude of the electron spin and
Publicado em: 2003
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21. Otimização da operação de sistemas de distribuição de agua abastecidos por bombeamento e reservatorios de regularização
In the present work it was developed an optimization model to water distribution systems operation, supplied by multiple pump stations and multiple reservoirs regulation. The difficulties to reach an appropriate modelling and the excessive simplification of the models have been delaying the appearance of practical solutions more adapted to dimensioning and o
Publicado em: 1999
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22. Solutions of a Lagrangian system on 𝕋2
A Lagrangian system on 𝕋2 that has been studied earlier under a geometrical condition and found to possess a pair of solutions, H±, homoclinic to periodic solutions, v±, of a given homotopy type, is considered further. It is shown with the aid of H± and variational arguments that, in fact, there is a much richer structure of homoclinics and heteroclini
The National Academy of Sciences.