The work studied the possibility of obtaining of the high-purity samples of zirconium and hafnium by the method of zone recrystallization of round rods with electron-beam heating in a vacuum of 1∙10-4 Pa. Some meltings were carried out in a constant electric field with the variability of its connection. It is shown that the simultaneous passage of several refining processes (evaporation of highly volatile metallic impurities, zone recrystallization with directional displacement of impurities to the end of the sample, electrotransport) made it possible to efficient refining of zirconium both from metallic impurities and from interstitial impurities. The best degree of purification was achieved when zone melting carrying out in an electric field directed opposite to the zone movement. In this case, the displacement of interstitial impurity ions coincided with the direction of movement of the liquid zone. Samples of zirconium with a purity of 99.89 wt. % were obtained (the concentration of aluminum was reduced by 5, iron - 11, copper - 45, chromium - 75, silicon - 10, titanium - 2.5, oxygen - 3.3, nitrogen - 3, carbon - 2 times). The hafnium samples refined by the zone recrystallization method were characterized by a purity of 99.85 wt. %. The concentrations of both all metal impurities and interstitial impurities were significantly reduced (concentration in wt% oxygen was 0.011, carbon - 0.0018, nitrogen - 5∙10-5). A study of gas evolution from samples of iodide hafnium and refined hafnium was carried out. It was found that the maximum gas release peak fell on the temperature range of 500 ... 550 °C. The use of an integrated approach, including high-temperature heating, stages of zone melting at different rates, and thermal cycling in the range of the polymorphic transformation temperature, made it possible to obtain single-crystal hafnium samples. According to X-ray diffraction data, the parameters of the hafnium crystal lattice were determined: а = (0.31950 ± 5·10-5) nm and с = (0.50542 ± 5·10-5) nm (at 298 K), which corresponds to the density ρ = 13.263 g/cm3 and axial ratio с/a = 1.5819.
The article deals with the influence of negative factors of working conditions on the health status of NSC KIPT personnel when working with beryllium. Beryllium and its compounds render a general toxic, allergenic and carcinogenic effect on the organism. The high biological activity and toxicity of Be is due to its chemical activity and penetrating ability. The chronic professional disease such as berylliosis occurs as a result of prolonged systematic exposure on the organism of adverse factors. Elemental analysis of biosubstrates provides important information, that in combination with symptoms and other laboratory parameters, can help in the early diagnostics of physiological violations associated with metabolic disorders and exposure of toxic elements. The blood and hair samples were taken from 28 people, among which 5 patients were selected as a control group, and a group of 23 people were former employees of the beryllium production. The content of chemical elements in the biological substrates (blood and hair) of employees was determined by nuclear-physical methods. An elemental analysis was performed on the analytical nuclear physics complex appliance “Sokol”. The methods based on registration of characteristic X-ray radiation of atoms and g-radiation of nuclei excited by accelerated protons is used. After measurements, data arrays were obtained on the content of 14 chemical elements (N, Na, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Sr, Pb) in blood and hair. The processing of data arrays was carried out using the principal component method which is related to chemometrics technologies. As a result of the work, an analytical program was composed in MATLAB codes which were used to determine the content of elements in biosubstrates that are most sensitive to changes in external conditions. This made it possible to identify certain groups of patients who have different health state indicators, as well as to see the similarities or differences between patients depending on the different concentrations of chemical elements in the blood or hair.
The physical substantiation and an experimental study results of the application of zone recrystallization method in an electric field for the refining of titanium are presented. The elemental composition, microstructure and microhardness of the samples have been investigated. It is shown that refining process made it possible to significantly reduce the content of both metallic and gas-forming impurities. The oxygen concentration was reduced by 2.2 (from 0.033 to 0.015 wt.%), carbon – by 3.3 (from 0.01 to 0.003 wt.%), nitrogen – by 22 times (from 0.009 to 0.0004 wt.%). The purity of the obtained samples was characterized by a value of 99.95 wt.% by titanium content. The total amount of impurities had been reduced by a factor of 2.4 (from 0.12 to 0.05 wt.%).
The paper analyses environmental impact caused by the Chornobyl accident on the Zaporizhzhya NPP (ZNPP) location area. Data processing technique is proposed to detect pollution sources in the NPP region. The movement of air masses within the ZNPP 30-km zone has been analyzed. Air flow maps have been developed, and the distribution of radionuclide particles in air over the territory under study in 1986 has been determined.
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