kinetics

The study examined the physico-chemical characteristics and combustion kinetics of petroleum coke or petcoke (PCK). The results revealed that PCK contains significantly high carbon, fixed carbon, and calorific value with low sulphur, and ash content. The combustion characteristics of PCK revealed the temperatures of ignition ranged from 764 to 795 K; peak decomposition from 808 to 875 K and burn-out from 857 to 933 K. The combustion performance and reactivity analyses were examined based on the ignition ratio, devolatilization ratio, burnout ratio, and combustion characteristic factor.

The influence of cavitation on a decrease of the number of microorganism colonies has been investigated. Our results have shown that the number of viable microorganisms in water dispersion during first 30 minutes of sonication increased till maximum. Then their quantity sharply decreased. A kinetic model of ultrasonic degradation of yeast cells aggregates was proposed.

The structure of an emulsion formed in wastewater from edible oils production has been investigated. The type of emulsifier has been determined and the method of emulsion destruction has been proposed, providing further quality treatment of wastewater via liquid-extraction method. The resulting equilibrium and operating lines of the process were received. The number of transfer stages has been determined. The mathematical model of liquid-extraction wastewater treatment was built.

Extraction of glucomannan from crude porang flour by acid hydrolysis and ethanol precipitation was studied. Effects of acid concentration, temperatures and time were investigated, kinetics model of the process was developed and the parameters were evaluated based on experimental data. New data on yield and purity of glucomannan under various conditions were obtained.

The article is devoted to the process of extraction of oil from rapeseed and sunflower seeds and meal by an extraction method based on the study of the kinetic regularities of the process.

The kinetics of copper ions adsorption by natural zeolite has been investigated in the apparatus with mechanical stirrer. The presence of external diffusion and pore diffusion area was established. For the external diffusive area, the dependence of mass transfer coefficient on stirrer rotation speed was confirmed; the dependence was described using a criterial equation. For the pore diffusion area, the equation is adduced by means of which the effective coefficient of pore diffusion was calculated.

Film systems based on chitosan of various molecular weight (334000 Da and 113000 Da) and the antibiotic of an aminoglycoside row (amikacin) have been investigated. The equations of Ritger-Peppas, Hixson-Crowell and Hopfenberg, describing kinetics of medicine release have been analyzed. It is shown that the release of amikacin from films of chitosan acetate under the conditions of interface diffusion processes and dissolution (hydrolysis) of a polymeric matrix is described more correctly by Hopfenberg’s equation.

The work is dedicated to theoretical and experimental investigations of kinetics and dynamics of filtration drying of capillary and pore materials, and mineral granulated fertilizers, in particular. The proposed physical model of a moist particle and the differential system of equations which describes heat exchange in the second drying period enables to determine the transfer velocity of mass-exchange zone in a dispersion layer of the material during filtration drying.

A BisGMA, TEGDMA monomer mixture at weight ration 2:1 was UV-cured with CQ to form commonly used dental materials. Three types of fillers at different particle size were added at different weight concentrations. Reaction rates k, time vs rate were studied for all the systems.