Reaction Diffusion Equation
Mostrando 1-12 de 24 artigos, teses e dissertações.
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1. Unified comprehension of the kinetics of isothermal ceramic processes under field-free and resonant wave-field conditions
Abstract This paper proposes a unified comprehension of the isothermal ceramic process kinetics stemming from mesoscopic irreversible thermodynamics. Accordingly, a unified process kinetic equation (UPKE) is derived, which predicts that the global isothermal process rate of any ceramic process is, in general, nonlinearly related both to its activation energy
Cerâmica. Publicado em: 2021-03
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2. Efficient numerical method for solution of boundary value problems with additional conditions
Abstract An efficient numerical method for solution of boundary value problems with additional condition is presented. The approach is based on the shooting method but the procedure of seeking “the proper shot” allows one to satisfy “additional” boundary conditions. General considerations are illustrated by a real example. The computational example c
Braz. J. Chem. Eng.. Publicado em: 2017-07
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3. A modified orthogonal collocation method for reaction diffusion problems
A low-order collocation method is often useful in revealing the main features such as concentration and temperature profiles and the effectiveness factor for porous catalyst particles. Two modifications are introduced in this paper to make the method more efficient. The first modification is to add an extra collocation point at the center of the particle. It
Braz. J. Chem. Eng.. Publicado em: 2014-12
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4. Evaluation of decomposition kinetics of poly (ether-ether-ketone) by thermogravimetric analysis
The non-isothermal thermogravimetric methods have been used extensively for the determination of kinetic parameters in polymers. The poly (ether ketones) are used as matrix in advanced high performance composites due its high thermal stability, excellent environmental performance and superior mechanical properties. In this work, the non-isothermal decomposit
Mat. Res.. Publicado em: 17/12/2013
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5. The asymptotic solutions for boundary value problem to a convective diffusion equation with chemical reaction near a cylinder
The work deals with a boundary value problem for a quasilinear partial elliptical equation. The equation describes a stationary process of convective diffusion near a cylinder and takes into account the value of a chemical reaction for large Peclet numbers and for large constant of chemical reaction. The quantity the rate constant of the chemical reaction an
Lat. Am. j. solids struct.. Publicado em: 2013-01
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6. Mínimos locais de funcionais com dependência especial via Γconvergência: com e sem vínculo
Na primeira parte deste trabalho, abordamos a existência de soluções estacioná-rias estáveis para uma classe de equações de reação-difusão com dependência espacial em domínios limitados 2 e 3-dimensionais. Esta abordagem foi feita via existência de mínimos locais dos funcionais de energia correspondentes. Para tal, foi suficiente encontrar cond
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/05/2011
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7. A multilayer model to simulate rocket exhaust clouds
Abstract This paper presents the MSDEF (Modelo Simulador da Dispersão de Efluentes de Foguetes, in Portuguese) model, which represents the solution for time-dependent advection-diffusion equation applying the Laplace transform considering the Atmospheric Boundary Layer as a multilayer system. This solution allows a time evolution description of the concentr
J. Aerosp. Technol. Manag.. Publicado em: 2011-04
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8. Estudo numérico da aplicação do método dos elementos finitos de Galerkin e dos mínimos quadrados na solução da equação da convecção-difusão-reação tridimensional / Numerical study of the application of Galerkin and least squares finite element methods in the solution of the tridimentional convection-diffusion-reaction equation
This paper the application of the Finite Element Method in variants Galerkin and Least Squares with auxiliary equations for the numerical solution of partial differential equation that models the convection-diffusion-reaction defined over a three-dimensional domain in steady state. In the spatial discretization were used hexahedrons elements with eight (line
Publicado em: 2011
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9. Taxa de convergência de atratores de algumas equações de reação-difusão perturbadas. / Rate of convergence of attractors de some reaction-difusion equations pertubadas
In this work we study the asymptotic nonlinear dynamical of some reaction-diffusion parabolic equations under perturbations in parameter and singular perturbations in a dumbbell domain. More precisely, we treat of the attractors from these problems, we seek understand the dependence these asymptotic set of states in relationship the parameter, investigating
Publicado em: 2010
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10. Critical behavior in reaction-diffusion systems exhibiting absorbing phase transitions
Phase transitions of reaction-diffusion systems with a site occupation restriction, particle creation requiring n > 2 parents, and in which explicit diffusion of single particles (A) is possible, are reviewed. Arguments based on mean-field approximation and simulations are given which support novel kind of nonequilibrium criticality. These are in contradicti
Brazilian Journal of Physics. Publicado em: 2003-09
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11. Static- and dynamical-phase transition in one-dimensional reaction-diffusion systems with boundaries
A general system of particles (of one or several species) on a one dimensional lattice with boundaries is considered. Two general behaviors of such systems are investigated. The stationary behavior of the system, and the dominant way of the relaxation of the system toward its stationary system. Bases on the first behavior, static phase transitions (discontin
Brazilian Journal of Physics. Publicado em: 2003-09
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12. Mass transfer in porous media with heterogeneous chemical reaction
In this paper, the modeling of the mass transfer process in packed-bed reactors is presented and takes into account dispersion in the main fluid phase, internal diffusion of the reactant in the pores of the catalyst, and surface reaction inside the catalyst. The method of volume averaging is applied to obtain the governing equation for use on a small scale.
Brazilian Journal of Chemical Engineering. Publicado em: 2003-06