Results 1 - 10 of 20521
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[en] A selection of topics which are representative of the continually expanding area of polymer degradation is presented. The aspects emphasised include the products of degradation of specific polymers, degradation by high energy radiation and mechanical forces, fire retardant studies and the special role of small radicals in degradation processes. (author)
[en] As an object of a research AI-95 gasoline samples were used. Laboratory studies were carried out on a gamma source 60''Co with a dose rate of P 0.18Gy/s within the absorbed doses of D=15-78kGy.Impact of radiation on operational characteristics of fuels in static conditions on a regular technique before radiation was researched. The aim of this work is to study the effect of ionizing radiation on hydrocarbons from fuels from Azerbaijan's oils. The results of such studies allow one to assess the radiation stability of fuels, to determine the effect of irradiation on the total composition of fuels and possible changes in the qualities of fuels.
[en] On the basis of an analysis of the data of their own studies and those of other researchers, the authors examine the question of the role of primary radicals of the sugar fragment of DNA in the formation of so-called alkali-labile sites in this polymer during γ irradiation of DNA solutions and cells. Conclusions are drawn on the mechanisms of the conversion of radicals of this type (Cn1', n = 1, 2, 4) with the formation of end products detectable by various methods - a modified sugar unit in DNA, labile to the action of alkali. 13 refs., 1 fig
[en] The kinetics of radiolysis processes of 9 chlorous-organic pesticides (hexachlorbenzene, α- HCH, β-HCH, lindan, 4,4'-DDE, 4,4'-DDD, 4,4'-DDT, aldrin and heptachlor) solutions (10 - 1000 ug/l) in hexane at 13,8; 27,7; 67,4 and 105,4 kGy doses was studied and the radiation-chemical yields of conversion processes were calculated in the work. It was identified that the conversion of pesitides of 105,4 kGy dose is 65-95 percent, radiation-chemical yields are (0,009 - 1,247) · 10-3 molecules/100 eV. Increasing of initial concentration leads to the radiation-chemical yields raising. Different radiation-chemical yields observed for various pesticide conversion processes may be due to the variations in their reaction rate with hydrogen atoms and radicals. The difference observed in various isomers (α-HCH, β-HCH and γ-HCH) may be due to the energy of spherical isomeric structures with C - Cl bonds in their molecules
[en] As a research object, samples of AI-92 petrol from Azerbaijan oil were used. Laboratory studies were carried out on the gamma source of Co60 at a dose rate of P = 0.18 Gy/s and an absorbed dose of D=0.64 kGy at different temperatures (50-250 degree C). Combined effect of radiation and temperature on AI-92 motor petrol under static conditions was investigated by the usual method before and after irradiation. The methods used to determine the radiation stability are based on the irradiation of the product and the subsequent determination of the changes that occurred therein. Radiation oxidations of processes were considered in the high-temperature region, when chain processes occur. The results of chromatographic, IR-spectroscopic studies are presented. Concentrations, radiation-chemical yields of the produced gases of petrol samples after irradiation at different temperatures were established and their radiation resistance is estimated.
[en] The kinetic regularities of the formation of gaseous products obtained by the conversion of n-hexane on the surface of nano-ZrO2 at room temperature under the influence of radiation were studied. It was found that in the range of absorption doses, ΔD = 0-14 kGy, the yield of molecular hydrogen in the gas phase increases linearly, and the radiation-chemical yield is G(H2) = 9 molecules/ 100 eV,which is 1.8 times more than the yield in the homophase.
[en] The general results of researches of interaction of zirconium nano powders with water are presented. It is proved that in the conditions of rather low temperatures, nano powder of zirconium interacts with water, emitting gaseous hydrogen. Process of interaction is followed by chemical effects, fall of water temperature. Advantages and disadvantages of use of zirconium nano powder for hydrogen production in the industry are found out. The main problem of the present-finding of new power sources which shortly would replace oil, gas and coal which reserves, according to experts, were exhausted in the next years. In recent years nuclear power intensively develops. Intensive growth of nuclear power creates a problem of burial of radioactive waste. One of the main projects of waste disposal is their clarification from Earth and sending by means of space crafts towards the Sun as accumulation of waste on Earth leads to growth of incidence of the population. Now, such project demands an investment of large sums
[en] The review illustrates the progress that has been made in recent years in understanding the radiation chemistry of nucleic acids. Many questions remain to be answered, but already the field is moving towards determining the nature of damage which actually occurs in living organisms, and applying present knowledge to developing agents to modify effects of radiation in vivo