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Nedávné pokroky v molekulárních simulacích termodynamického chování tekutých soustav.
Aim, Karel ; Lísal, Martin ; Nezbeda, Ivo ; Ungerer, P. ; Teuler, J.-M. ; Rousseau, B.
An overview of the recent developments in molecular computer simulation techniques used to calculate phase equilibria and thermodynamic properties of fluid systems is given. Particular attention is paid to the methodologies as follows: (i) reaction Gibbs ensemble Monte Carlo (RGEMC), which allows accurate phase equilibrium predictions for mixtures by employing experimental pure-component vapour pressure data in the computational procedure (ii) direct Monte Carlo simulation of Joule-Thomson processes, (iii) Monte Carlo simulations at fixed entropy, and (iv) an implemented parallelized sampling version of the Gibbs ensemble Monte Carlo (GEMC), which by-passes the physical transfer of complex molecules between boxes representing different phases by computing the chemical potential in an NVT ensemble (and is applicable also to flexible molecules). Example applications of the considered techniques for real fluid systems ar
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Koncové efekty v rotační viskometrii za přítomnosti zdánlivého skluzu
Wein, Ondřej ; Večeř, Marek ; Havlica, Jaromír
Common methods of treating primary data from rotational viscometry are tested using numerical simulations of primary circular flow of shear-thinning liquids in an actual sensor Z40 DIN according to ISO 3219 and a new KK (Morse-taper) sensor, suggested for rotational viscometry under slip effect. Theory of the sensors is presented, including the conversion of primary data into fluidity and slip viscometric material functions, as well as a statistical analysis of their relevance. The data treatment, based on the concept of local filtration, is illustrated on several aqueous solutions of Hercules CMC and Welan gum.
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Standardní adsorpční isotermy argonu a dusíku pro Al2O3, TiO2, MgO a CPG
Matějová, Lenka ; Schneider, Petr ; Šnajdaufová, Hana ; Šolcová, Olga
The standard (master) isotherms describe relation between thickness, t, of adsorbed film and relative pressure, x (x = p/po is the adsorptive pressure, p, relative to adsorptive vapor pressure po, at measurement temperature,).They appear during the assessment of the core size, rk(x) (as determined by the Kelvin equation) in a pore just filled/emptied by/from capillary condensate, r(x) (r(x) = rk(x) +t(x)) and during the evaluation of adsorbed amount in pores free of capillary condensate. Such isotherms were experimentally determined for Ar and N2 on Al2O3, TiO2, MgO and Controlled Porous Glass.
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Nízkoteplotní příprava příprava tenkých vrstev TiO2
Bartková, H. ; Klusoň, P. ; Šolcová, Olga ; Cajthaml, Tomáš
This work was based on a rational design of a titania particle form and its function through the use of template-assisted sol-gel generation at temperatures compatible with plastic supporting substrates. Specifically reverse micelles of nonionic surfactants were used as templates to impose the nanometer scale order. The process yielded relatively high surface area particles that were uniform in size and shape.
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Podrobné materiálové charakteristiky z transportních procesů a texturní analýzy
Soukup, Karel ; Šolcová, Olga ; Schneider, Petr
The structure of porous solids is traditionally characterized by mercury porosimetry or physical adsorption of inert gases. The transport characteristics can be advantageously determined by evaluation of simple transport processes (e.g. multicomponent gas diffusion or permeation). Transport characteristics and textural properties of a set of porous catalyst pellets with wide range of mean pore radii (from 30 up to 3000 nm) were determined. by evaluated of multicomponent counter-current gas diffusion and permeation measurements. For gas diffusion the results from the Wicke-Kallenbach and Graham cell were compared.
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