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Heterogeneous Solids (heterogeneous + solid)

Distribution by Scientific Domains

Chemistry	60%

Selected Abstracts

Some methodological problems concerning nonisothermal kinetic analysis of heterogeneous solid,gas reactions

INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 10 2001
P. Budrugeac
Isoconversional methods, those using only one curve , = ,(T) (, is the conversion degree and T is the temperature), and invariant kinetic parameter method were applied to estimate the kinetic parameters from the following nonisothermal data: (1) simulated TG curves for a single reaction; (2) TG curves for thermal degradation of PVC; and (3) TG curves for the dehydration of CaC2O4·H2O. The results obtained by applying various methods for the same system are compared and discussed. Finally, a procedure of kinetic analysis is suggested. Its application could lead to kinetic parameter values that can be used to predict either , = ,(t) curves for other heating rates or , = ,(T) curves for isothermal conditions. © 2001 John Wiley & Sons, Inc. Int J chem Kinet 33: 564,573, 2001 [source]

Finite cover method for linear and non-linear analyses of heterogeneous solids

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 9 2003
Kenjiro Terada
Abstract We introduce the finite cover method (FCM) as a generalization of the finite element method (FEM) and extend it to analyse the linear and non-linear mechanical behaviour of heterogeneous solids and structures. The name ,FCM' is actually an alias for the manifold method (MM) and the basic idea of the method has already been established for linear analyses of structures with homogeneous materials. After reviewing the concept of physical and mathematical covers for approximating functions in the FCM, we present the formulation for the static equilibrium state of a structure with arbitrary physical boundaries including material interfaces. The problem essentially involves the discontinuities in strains, and possibly has the discontinuities in displacement caused by interfacial debonding or rupture of material interfaces. We simulate such non-linear mechanical behaviour after presenting simple numerical examples that demonstrate the equivalence between the approximation capabilities of the FCM and those of the FEM. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Monte Carlo simulation of adsorption using 2-D models of heterogeneous solids

AICHE JOURNAL, Issue 3 2003
V. F. Cabral
A new methodology proposed here correlates the adsorption of pure components and predicts the adsorption of binary and ternary mixtures in homogeneous and heterogeneous solids. This methodology uses the algorithm of molecular simulation in the grand canonical ensemble as an equation of state for the adsorbed phase. In all case studies presented, the simulations described the adsorption characteristics of systems. The results obtained for the adsorption of the binary mixtures of propane,CO2 and propane,H2S, which are strongly nonideal, were quite satisfactory, showing the potential of this technique for the description of real systems. [source]