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The effects of dispersed oxides Fe2O3, Cr2O3, α-PbO, β-PbO, PbO2, SiO2 on the processes of radical polymerization of styrene are studied. It is shown that the dispersed oxides affect the polymerization rate and the response of the thermal decomposition of radical initiators. Peroxides are adsorbed on the surface of mineral oxides and decomposed into free radicals. On the surface of SiO2 and Cr2O3, a heterolytic decomposition of peroxides takes place. The oxide introduced into the polymerization system reduces the molecular weight of the polymer that forms under these conditions. The degrees of grafting macromolecules to the surface of oxides were found. [ABSTRACT FROM AUTHOR]

The adsorption of oligo(sebacoyl peroxide) on Aerosil and MgO and benzoyl peroxide on Fe 2O 3, Cr 2O 3, and V 2O 5 has been studied. It has been established that peroxide adsorption on the considered adsorbents is described by the Langmuir equation. Benzoyl-peroxide adsorption increases in the series Fe 2O 3 < Cr 2O 3 < V 2O 5. The process of thermal decomposition of peroxides in the presence of the listed adsorbents has been studied. The overall reaction of peroxide decomposition comprises two components, i.e., the decomposition processes occurring in a solution and on an adsorbent surface. Kinetic and activation parameters of the thermal-decomposition reactions in the solutions and on the surfaces have been determined. [ABSTRACT FROM AUTHOR]

We study the influence of temperature of a working medium and loading frequency on the contact fatigue of 20KhN3A and ShKh15 steels in oil and in a 3% NaCl aqueous solution. It is shown that, as the loading frequency increases, the contact fatigue of steels increases in a 3% NaCl aqueous solution but does not change in oil. At the same time, as temperature increases, the contact fatigue decreases in a 3% NaCl aqueous solution but remains almost constant in oil. It is shown that the outlined behaviors of the analyzed steels is explained by the action of the components of working media and their concentrations in the surface layers in the course of the tests. [ABSTRACT FROM AUTHOR]

The results of the study of the length of the prenatal period of ontogenesis of 51 Ukrainian Red Dairy breed tribal cows are presented, and the relationship of this trait with the rate of growth of the organism in the postnatal period (at birth, at 6, 12 and 18 months) and dairy productivity for the first lactation are investigated. Also, at different stages of the prenatal period of ontogeny the dynamics of the mass of 66 fetus and some parenchymatous organs (liver, spleen, thymus) selected by anatomical preparation are determined. The aim of the research was to establish the possibility of predicting dairy productivity of Ukrainian Red Dairy breed cows over the length of the prenatal period and the effect of this period on the postnatal growth rate of the organism, and also to ascertain the existence of a regularity between the increase in fetus mass and the development of certain hemopoiesis organs at different stages of prenatal development. Laboratory animals were divided into three groups, depending on length of their prenatal period: less than 277 days-reduced (group I), 277-283 - medium (group II) and more than 283 days - extended period (group III). For 305 days of the first lactation, the advantage over milk yield, milk fat yield and milk protein belongs to animals with shortened duration of the prenatal period of ontogenesis in comparison with contemporaries who had an extended period with a statistically significant difference (P < 0.05). A further study in the short term may be a study of the relationship between the duration of the prenatal period and the rate of fetal growth with the subsequent forming of the physique, and in the long term turning into the study of the relationship between the duration of the prenatal period and the rate of fetal growth with a duration of productive use and lifelong productivity. [ABSTRACT FROM AUTHOR]