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Analysis of Gas Transport through Macroporous Media.
Čapek, P. ; Hejtmánek, Vladimír
The aim of this study was to evaluate diffusional and forced flow in the cylindrical capillary under defined boundary conditions and to determine the effective diffusivities of gases (hydrogen, nitrogen, helium, and argon) in selected macroporous media. The knowledge of these diffusional and forced flow densities helps us to formulate many demands on the experimental apparatus and to estimate the error of the effective diffusivity. The relation between molar flux and the molar concentration gradient was described by the model of the mean transport pore. The experimental values of the effective diffusivities have agreed with the ones calculated for porous media replicas very well.
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Obrazová analýza řezů pórovitého materiálu
Hejtmánek, Vladimír ; Čapek, P.
Two methods of image analysis of cross-sections through two-phase porous media are compared. Linear filtering uses the recursive (IIR) Gaussian filter with the same vertical and horizontal blur radii. The images are also treated by removing small clusters of pixels in the void and solid phases. After linear filtering and before removing small clusters, the grey-level threshold is determined in order to partition all grey pixels into pore and solid pixels. Linear filtering reduces the specific surface very efficiently creating ``smooth'' pore walls and leaves small clusters of pixels in the images. Removing preserves ``rough'' pore walls and removes simultaneously small clusters from both the phases.
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