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  • Author or Editor: V. Kutarov x
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Abstract  

The paper presents evaluation of energy distribution of n-octane and pore-size distribution functions on the alumina oxide surface (e.g. total heterogeneity) of on the basis one experimental run. the Q-TG mass loss and derivative Q-DTG mass loss curves of n-octane thermodesorption from the alumina oxide sample were made using a hungarian derivatograph with an analyser equipped with an automatic ultraslow procedure and a special crucible of maintaining the quasi-isothermal heating procedure to increase the resolution of thermal analysis. a new theoretical and experimental procedure was developed for evaluation of distribution functions of liquid preadsorbed on the mesoporous surface from special thermogravimetry. An example of the approach to quantitative description of the energetic and structural heterogeneities of alumina oxide surface is given.

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Abstract  

In this paper the theoretical approach and applications of Cahn ultramicrobalance to kinetic study on the thermal decomposition of the high-temperature Y1Ba2Cu3O7-x superconductor are presented. Thermogravimetric in situ measurements of oxygen loss from Y1Ba2Cu3O6 samples heated isothermally in a relatively high dynamic vacuum were performed with a Cahn RG electrobalance. Single-phase orthorhombic samples of composition Y1Ba2Cu3O7-x (highest oxygen content) were synthesized from stoichiometric (1:2:3) mixtures of high-purity Y2O3, BaCO3 and CuO. The original 1:2:3 mixture was prepared by the two-stage procedure described earlier. The crystal structure of the sample in the original orthorhombic phase was controlled by the X-ray powder method (CuKα radiation) using a Stadi P Stoe diffractometer with a position-sensitive detector. Activation energy is estimated from appropriate Arrhenius plots.

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Abstract  

Specific surface area and pore size distribution are determined usually from adsorption isotherms at low temperatures using nitrogen or noble gases. These are not absolute parameters and the measuring methods are fraught with serious difficulties. General problems of sorption measurements and recent developments are discussed. To obtain information for practical purposes these measurements need to be supplemented by investigations of the sorbate/sorbent system used in practice. Results of the measurement of nitrogen and water vapour adsorption on different materials are compared.

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Abstract  

Energetic heterogeneity of adsorbents is conditioned by the differences in topology of adsorption centres, dispersion of pore sizes and other factors. This paper describes theoretical and experimental studies that demonstrate a method for estimation of the energetic heterogeneity of adsorbents by making use of the results from single thermogravimetry Q-TG and Q-DTG curves, recorded under quasi-equilibrium conditions, for preadsorbed liquid on a porous solid surface.

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Abstract  

In describing multi-layer adsorption it is common to use standard isotherms. To establish such isotherms experimental data are required at a wide range of adsorptive pressure. This paper presents the theoretical and experimental analysis of the new t δ-method, which is suitable to predict type II multi-layer adsorption isotherms on the basis of only two adsorption values, measured in the area of mono- and multi-layer saturation and of the surface fractal dimension of the adsorbent.

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Abstract  

The new method of diffusion coefficient calculations from thermogravimetry Q-TG data has been presented. Programmed thermodesorption of polar and apolar liquids from aluminium oxide and montmorillonite-Na and -La samples in quasi-isothermal conditions has been made. The result from above method was compared with literature data and good correlation were obtained.

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