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Anomalous Relaxation in Disordered Media

Published online by Cambridge University Press:  10 February 2011

Mariela Araujo  and
Orlando Gonzalez
Mariela Araujo
Affiliation:
Reservoir Department. INTEVEP S.A, Apartado 76343. Caracas 1070-A Venezuela.
Orlando Gonzalez
Affiliation:
Departamento de Física, Universidad Central de Venezuela. Caracas, Venezuela.
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Abstract

Several random walk-algorithms are used to model relaxation processes on disordered structures. Substrates are regular lattices in d = 1,2 with disorder variables attached to each lattice site. For the simulations, we consider diffusing particles obeying different rules according to the transport process being studied. Relaxation description is done in the time domain by calculating the characteristic function F(k,t), and in the frequency domain through the study of the complex susceptibility χ(k,ω). Two types of relaxation mechanisms are seen both in simulations and in Nuclear Magnetic Resonance (NMR) experiments done on sandstones. These are expressed as stretched exponential forms of the relaxation function, and the Cole-Cole form of the imaginary part of the complex susceptibility. Longitudinal and transversal NMR measurements were done on fully saturated samples at 90 MHz. NMR relaxation data can be qualitatively understood using the random walk models proposed here.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 463: Symposia EE – Statistical Mechanics in Physics and Biology , 1996 , 257
Copyright
Copyright © Materials Research Society 1997

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References

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