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Teplotní závislost dodatkových molárních objemů v systémech oktan-aromatické uhlovodíky
Linek, Jan ; Morávková, Lenka ; Wagner, Zdeněk
Densities were measured for the liquid benzene and 1,3,5-trimethylbenzene, and for nine their mixtures at four temperatures between 298.15 K and 328.15 K and at pressures up to 40 MPa. An apparatus for density measurements of liquid and liquid mixtures whose main part is a high-pressure vibrating-tube densimeter working in a static mode was used for the measurement. The density data were fitted to the Tait equation and the isothermal compressibilities were calculated with the aid of this equation. Excess molar volumes were also calculated from the densities and fitted to the Redlich-Kister equation.
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Vztah mezi kapilárním tlakem a permeabilitou studovaný pomocí modelu trojrozměrné sítě pórů
Čapek, P. ; Hejtmánek, Vladimír
The results of this study clearly indicate that, in the network representation of a porous medium, the cross-sectional shape of throuds, the chamber-to throut aspect ratio, and spatial correlations between chambers and adjacent throats have the significant unfluence on permeability and mercury-air displacement. Since the critical capillary pressure is solely determined by the throat size and shape in this study, the chamber-to throat aspect ratio is the only pore structure parameter, which does not have any influence on the capillary pressure curves at all
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Určení transportních charakteristik z protiproudé difuze plynů
Soukup, Karel ; Šolcová, Olga ; Schneider, Petr
Two types of a diffusion cell commonly used for studying of isobaric counter-current diffusion in porous solids are compared. Both cells enable determination of diffusion coefficients and transport characteristics of porous materials. Transport parameters are material constants of the porous solids and can be evaluated through application of a suitable model of porous solids to results of measurements of transport processes withing the porous structure
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Distribuce porů z permporometrických měření
Šolcová, Olga ; Schneider, Petr
Two measurement modes for obtaining wet-curves were suggested and verified. In the figure the obtained wet and dry curves for two catalysts are shown. It was verified that LEPP gives consistent pore size distribution of flow-through pores and, thus, should be tried as the standard texture characteristic suitable for prediction and/or simulation of gas flow in porous media
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Vliv parciální neutralizace na katalytickou aktivitu ionexů
Holub, Ladislav ; Hanková, Libuše ; Jeřábek, Karel
Concentration of acid centers in a commercional ion exchanger catalyst was controlled by partial neutralization of sulfonic groups with various primary, secondary and tertiary amines of different molecular size. The efect of acid centres concentration on the activity of ion exchanger catalyst was tested by measurements of initial reaction rate of reesterification of ethyacetate with methanol in a CSTR-type reactor. There was found that the slope of the dependence of the catalyrtic activity on the degree of the resin neutralization strongly depends on the amine basicity.
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