kinetics

Зменшення енергетичних затрат процесу сушіння у виробництві цукатів з груш

Досліджено зміни температурних режимів процесу сушіння у виробництві цукатів
з груш. Проведені експериментальні дослідження з теплообміну та кінетики сушіння
цукатів з груш за різної температури. Експериментально підтверджено доцільність
проведення процесу сушіння за температур цукатів, що дорівнюють температурі
гарячого теплового агенту. Згідно з тепловим балансом розраховано кількість енергії,
накопиченої шаром груші, та необхідної енергії для випарювання вологи. Встановлено,

Peculiarities of medicinal substance release under the conditions of interface diffusion process and hydrolysis of a polymeric matrix

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.

Mass Exchange Dynamics During the Second Filtration Drying Period

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.

Effect of filler type, content and size on the UV photocuring dental ma

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.

Regularities of low-waste technology of wastewater treatment by coagulation method

Mechanisms of wastewater purification from surface-active substances and of sulphuric acid dissolution of iron-containing sludge formed during the previous process have been established. Kinetic regularities of metal-containing sludge dissolution in sulphuric acid have been investigated. Kinetic equation which adequately presents the experimental data has been proposed; constants of this kinetic equation have been calculated.

Alkylation of 2,6-di-tert-Butylphenol with Methyl Acrylate Catalyzed by Potassium 2,6-di-tert-Butylphenoxide

The kinetics of catalytic alkylation of 2,6-di-tert-butylphenol (ArOH) with methyl acrylate (MA) in the presence of potassium 2,6-di-tert-butylphenoxide (ArOK) depends on the method for the preparation of ArOK. The reaction of ArOH with KOH at temperatures > 453 K affords monomeric ArOK, which properties differ from those in the case of potassium 2,6-di-tert-butylphenoxide synthesized by the earlier methods. The regularities of ArOH alkylation depend on the ArOK concentration, the ArOH:MA ratio, and the effect of microadditives of polar solvents.

Potassium and Sodium 2,6-Di-tert-Butyl Phenoxides and their Properties

The determining factor of the reaction of 2,6-di-tert-butylphenol with alkaline metal hydroxides is temperature, depending on which two types of potassium or sodium 2,6-di-tert-butyl phenoxides are formed with different catalytic activity in alkylation of 2,6-di-tert-butylphenol with methyl acrylate. More active forms of 2,6-But2C6H3OK or 2,6-But2C6H3ONa are synthesized at temperatures higher than 433 K representing predominantly monomers of 2,6-di-tert-butylphenoxides which produce dimers when cooling.

The Characterization of Novel Biodegradable Blends Based on Polyhydroxybutyrate

the water transport and morphology (TEM data) shows the impact of polymer component ratio on the regulating water flux in a hydrophobic matrix. To elucidate the role of hydrophilicity of the second component presented in the PHB blends, we studied the PHB/PA blends where PA is the polyamide resin composed of statistical copolymer of hexamethyleneadipinate and ε-caprolactam in the ratio of 1:1. The complex of techniques including DCS and FTIR-imaging (for T-scale) demonstrates the interaction between PHB and PA in the temperature ranges of crystallization and melting.

Light Curable Dental Composites – Kinetics by Plasma and Halogen Lamps

A series of commercial dental composites curable by visible light have been investigated and compared in terms of their photoreactivity thanks to the photocalorimetry technique by using two different types of lamps, a conventional lamp (halogen lamp) from ESPE and a plasma lamp, Apollo 98E manufactured by DMDS. In terms of kinetics, dental composites cure in just a few seconds with plasma lamp compared to 20-40 s with halogen lamp allowing dentists to save time.