Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/56452
Type: Artigo de periódico
Title: Concentration-dependent diffusivity and anomalous diffusion: A magnetic resonance imaging study of water ingress in porous zeolite
Author: de Azevedo, EN
de Sousa, PL
de Souza, RE
Engelsberg, M
Miranda, MDD
Silva, MA
Abstract: Magnetic resonance imaging is employed to study water ingress in fine zeolite powders compacted by high pressure. The experimental conditions are chosen such that the applicability of Boltzmann's transformation of the one-dimensional diffusion equation is approximately satisfied. The measured moisture profiles indicate subdiffusive behavior with a spatiotemporal scaling variable eta=x/t(gamma/2) (0 <gamma < 1). A time-fractional diffusion equation model of anomalous diffusion is adopted to analyze the data, and an expression that yields the moisture dependence of the generalized diffusivity is derived and applied to our measured profiles. In spite of the differences between systems exhibiting different values of gamma a striking similarity in the moisture dependence of the diffusivity is apparent. This suggests that the model addresses the underlying physical processes involved in water transport.
Country: EUA
Editor: American Physical Soc
Rights: aberto
Identifier DOI: 10.1103/PhysRevE.73.011204
Date Issue: 2006
Appears in Collections:Unicamp - Artigos e Outros Documentos

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