539 research outputs found

    State export support in foreign countries

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    The given article represents the peculiarities of export and its support from the side of the government and some measures for it’s stability in foreign countriesye

    Thermal and Mechanical Characteristics of Polymer Composites Based on Epoxy Resin, Aluminium Nanopowders and Boric Acid

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    The epoxy polymers are characterized by low thermal stability and high flammability. Nanoparticles are considered to be effective fillers of polymer composites for improving their thermal and functional properties. In this work, the epoxy composites were prepared using epoxy resin ED-20, polyethylene polyamine as a hardener, aluminum nanopowder and boric acid fine powder as flame-retardant filler. The thermal characteristics of the obtained samples were studied using thermogravimetric analysis and differential scanning calorimetry. The mechanical characteristics of epoxy composites were also studied. It was found that an addition of all fillers enhances the thermal stability and mechanical characteristics of the epoxy composites. The best thermal stability showed the epoxy composite filled with boric acid. The highest flexural properties showed the epoxy composite based on the combination of boric acid and aluminum nanopowder

    Effect of electron beam irradiation on thermal and mechanical properties of epoxy polymer

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    This study investigates the thermal and mechanical properties of epoxy polymer after exposure to different doses of electron beam irradiation. The epoxy polymer was prepared using epoxy-diane resin ED-20 cured by polyethylenepolyamine. The irradiation of the samples was carried out with doses of 30, 100 and 300 kGy. The effects of doses on thermal and mechanical properties of the epoxy polymer were investigated by the methods of thermal gravimetric analysis, tensile test, and dynamic mechanical analysis. The thermal properties of the epoxy polymer slightly increased after irradiation at the heating in air. The tensile strength and Young's modulus of the epoxy polymer increased by the action of electron beam up to dose of 100 kGy and then decreased. The elongation at break decreased with increasing the irradiation dose

    Effect of Boric Acid on Volatile Products of Thermooxidative Degradation of Epoxy Polymers

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    The polymeric materials are characterized by high flammability. The use of flame retardants in order to reduce the flammability of polymers can lead to the formation of toxic gaseous products under fire conditions. In this work we studied the effect of boric acid on the volatile products of thermooxidative degradation of epoxy polymers. The comparative investigations were carried out on the samples of the unfilled epoxy resin and epoxy resin filled with a boric acid at percentage 10 wt. %. The analysis of the volatile decomposition products and thermal stability of the samples under heating in an oxidizing medium was performed using a thermal mass-spectrometric analysis. It is found that the incorporation of boric acid into the polymer matrix increases the thermal stability of epoxy composites and leads to a reduction in the 2-2.7 times of toxic gaseous products

    Effect of electron beam irradiation on thermal and mechanical properties of epoxy polymer

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    This study investigates the thermal and mechanical properties of epoxy polymer after exposure to different doses of electron beam irradiation. The epoxy polymer was prepared using epoxy-diane resin ED-20 cured by polyethylenepolyamine. The irradiation of the samples was carried out with doses of 30, 100 and 300 kGy. The effects of doses on thermal and mechanical properties of the epoxy polymer were investigated by the methods of thermal gravimetric analysis, tensile test, and dynamic mechanical analysis. The thermal properties of the epoxy polymer slightly increased after irradiation at the heating in air. The tensile strength and Young's modulus of the epoxy polymer increased by the action of electron beam up to dose of 100 kGy and then decreased. The elongation at break decreased with increasing the irradiation dose

    Thermal properties of epoxy composites filled with boric acid

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    The thermal properties of epoxy composites filled with boric acid fine powder at different percentage were studied. Epoxy composites were prepared using epoxy resin ED-20, boric acid as flame-retardant filler, hexamethylenediamine as a curing agent. The prepared samples and starting materials were examined using methods of thermal analysis, scanning electron microscopy and infrared spectroscopy. It was found that the incorporation of boric acid fine powder enhances the thermal stability of epoxy composites

    Study of the Effect of Radiation Dose Rate on the Stability of Various Organochlorine Pesticides

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    Abstract irradiated at dose of 10 kGy with dose rate varied from 8.3 ⋅ 10−3 up to 2.33 Gy/sec. It is found that the shape of the degradation degree relationship on dose rate is similar for different OCPs in polar and non-polar solvents (hexane, 2-propanol) and does not depend on the concentration of initial substance. The maximum of the OCP degradation degree is registered in the dose rate range of 0.23-0.43 Gy/sec. A lognormal distribution is considered as a function best fitting the experimental data. The OCP degradation mechanism could be explained by the ratio of active and recombined particles along the gradient of ionizing radiation intensity. Keywords: organochlorinated pesticide; irradiation, dose and dose rate of gammaradiation; radiation degradation; functional dependenc

    ALTERATION OF ACTIVE SUBSTANCE CONTENT IN "HEXACHLORAN DUST" PESTICIDE FORMULATION AT EXPOSURE TO ELECTRON BEAM

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    The most popular methods of organochlorinated pesticides (OCP) destruction, which are based on thermal dechlorination, are not ecologically safe. The other process – radiation-chemical degradation – has got some advantages. It does not involve high temperatures and expensive reagents. In this study, the effective OCP degradation was observed under irradiation of residuals of the active substance of ‘Hexachloran dust’ pesticide formulation, intended for utilization. Parameters for the preparation powder (dry form) exposure to electron beam are discussed. It is shown that at the exposure to electron beam at dose of 100 kGy, the degradation degree of hexachlorocyclohexane (HCH) isomers in a composition of active substance achieves 56.2–66.3%

    Professional Career of Youth as an Object of Sociological Research

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    The publication deals with the issues of professional career through the prism of sociology. The author reveals the contradictions of career building in modern youth in the conditions of individualism.В публикации рассматриваются вопросы профессиональной карьеры сквозь призму социологии. Автором выявляются противоречия построения карьеры у современной молодежи в условиях индивидуализма
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