Features Of The Phase Transformations In Titanium-containing Zinc Aluminosilicate Glasses Doped With Cobalt Oxide

We demonstrated the efficiency of the Raman spectroscopy method in the study of the process of the formation of the amorphous zinc aluminotitanate (ZAT) phase during the phase decomposition of the titanium-containing zinc aluminosilicate glasses doped with cobalt oxide. The quantitative dependences of the variation of the intensity of the Raman bands characteristic for amorphous and crystalline phases on the temperature of the thermal treatment and the cobalt oxide concentration have been obtained. The speed of phase decomposition with the separation of the nanosize crystals of zinc aluminate spinel (gahnite) and ZAT phase increases at low-temperature thermal treatments with increasing cobalt oxide concentration. The addition of cobalt oxide increases the amount of the amorphous ZAT phase separated during phase decomposition and increases its thermal stability during high-temperature treatments. It has been shown that the Co2+ ions enter the zinc aluminate spinel (gahnite) crystals precipitated during phase decomposition. It has been supposed that the composition of the residual glass is close to that of the quartz glass and it contains a very small amount of titanium-oxygen tetrahedra. © 2013 Pleiades Publishing, Ltd.392113123Golubkov, V.V., Dymshits, O.S., Petrov, V.I., Shashkin, A.V., Tsenter, M., Zhilin, A.A., Kang, U., Small-Angle X-ray Scattering and Low-Frequency Raman Scattering Study of Liquid Phase Separation and Crystallization in Titania-Containing Glasses of the ZnO-Al2O3-SiO2 System (2005) J. Non-Cryst. Solids, 351, pp. 711-721. , 10.1016/j.jnoncrysol.2005.01.071 1:CAS:528:DC%2BD2MXivVyqtro%3DMalyarevich, A.M., Yumashev, K.V., (2008) Tverdotel'Nye i Prosvetlyayushchiesya Sredy, , Belarusian National Technical University Minsk (Solid-State and Bleachable Media)Galagan, B.I., Godovikova, E.A., Denker, B.I., Meil'Man, M.L., Osiko, V.V., Sverchkov, S.E., Efficient Bleachable Filter Based on Co2+: MgAl 2O4 Crystals for Q-Switching of λ = 1.54 μm Erbium Glass Lasers (1999) Quantum Electron., 29 (3), pp. 189-190. , 10.1070/QE1999v029n03ABEH001448 1:CAS:528:DyaK1MXjs1ygtb0%3DYumashev, K.V., Denisov, I.A., Posnov, N.N., Prokoshin, P.V., Mikhailov, V.P., Nonlinear Absorption Properties of Co2+: MgAl 2O4 Crystal (2000) Appl. Phys., 70 (2), pp. 179-184. , 10.1007/s003400050029 1:CAS:528:DC%2BD3cXhslSgsrk%3DBoiko, R., Okhrimchuk, A., Shestakov, A., Glass-Ceramics Co2+: Saturable Absorber Q-Switch for 1.3-1.6 μm Spectral Region (1998) OSA Trends Opt. Photonics Ser., 19, pp. 185-188. , 1:CAS:528:DC%2BD3cXjsV2ntLw%3DDymshits, O., Shashkin, A., Zhilin, A., Volk, Y., Malyarevich, A., Yumashev, K., Formation and Passive Q-Switch Performance of Glass-Ceramics Containing Co2+-Doped Spinel Nanocrystals (2008) Adv. Mater. Res., 219, pp. 39-40Alekseeva, I., Baranov, A., Dymshits, O., Ermakov, V., Golubkov, V., Tsenter, M., Zhilin, A., Influence of CoO Addition on Phase Separation and Crystallization of Glasses of the ZnO-Al2O3-SiO2-TiO2 System (2011) J. Non-Cryst. Solids, 357, pp. 3928-3939. , 10.1016/j.jnoncrysol.2011.08.011 1:CAS:528:DC%2BC3MXhtF2ht7nLKang, U., Zhilin, A.A., Petrovsky, G.T., Dymshits, O.S., Chuvaeva, T.I., Structural Transformations of Nanometer Sized Crystals in CoO-Doped β-Eucryptite-Based Glass-Ceramics (1999) J. Non-Cryst. Solids, 258, pp. 216-222. , 10.1016/S0022-3093(99)00445-7 1:CAS:528:DyaK1MXns1arur0%3DFergusson, J., Wood, D.L., Van Utiert, L.G., Crystal-Field Spectra of d 3,7 Ions: V. Tetrahedral Co 2+ in ZnAl2O4 Spinel (1969) J. Chem. Phys., 51, pp. 2904-2910. , 10.1063/1.1672431Denisov, I.A., Volk, Y., Malyarevich, A.M., Yumashev, K., Dymshits, O.S., Zhilin, A.A., Kang, U., Lee, K.-H., Linear and Nonlinear Optical Properties of Cobalt-Doped Zinc Aluminum Glass-Ceramics (2003) J. Appl. Phys., 93 (7), pp. 3827-3831. , 10.1063/1.1555699 1:CAS:528:DC%2BD3sXitlens7g%3DGaleener, F.L., Leadbetter, A.J., Stringfellow, M.W., Comparison of the Neutron, Raman, and Infrared Vibrational Spectra of Vitreous SiO2, GeO2, and BeF2 (1983) Phys. Rev. B: Condens. Matter, 27 (2), pp. 1052-1078. , 10.1103/PhysRevB.27.1052 1:CAS:528:DyaL3sXpvVWntA%3D%3DBobovich, Y., Spectroscopic Investigation of the Coordination State of Titanium in Some Vitreous Solids (1963) Opt. Spektrosk., 14 (5), pp. 647-654Dymshits, O.S., Zhilin, A.A., Petrov, V.I., Tsenter, M., Chuvaeva, T.I., Golubkov, V.V., A Raman Spectroscopic Study of Phase Transformations in Titanium-Containing Lithium Aluminosilicate Glasses (1998) Glass Phys. Chem., 24 (2), pp. 79-98. , 1:CAS:528:DyaK1cXislyhsLk%3DBae, S.J., Kang, U., Dymshits, O., Shashkin, A., Tsenter, M., Zhilin, A., Raman Spectroscopy Study of Phase Transformations in Titania-Containing Lithium Aluminosilicate Glasses Doped with CoO (2005) J. Non-Cryst. Solids, 351, pp. 2969-2978. , 10.1016/j.jnoncrysol.2005.07.019 1:CAS:528:DC%2BD2MXhtVWgt7bPPorto, S.P.S., Fleury, P.A., Damen, T.C., Raman Spectra of TiO2, MgF2, ZnF2, FeF2, and MnF2 (1967) Phys. 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Estimation of the efficiency of the dry method of decontamination of surface contamination of alpha-emitting-radionuclides

The article describes the evaluation of the efficiency of using the technology of dry method of decontamination of α-radionuclides from working surfaces of premises for different materials, equipment and building structures. Materials and methods. Instruments for measuring of ambient dose equivalent rate (ADER) with a lower limit of 0.03 μSv/h. Specific activity of α-radionuclides in the samples was determined by radiometric, radiochemical and spectrometric methods using standard methods in the accredited laboratory. The measurements in situ were also carried out using the ISOCS «CANBERRA» mobile gamma-ray spectrometry system with high purity germanium detector and a collimator. Technological equipment included industrial vacuum cleaner with nozzles; high-pressure device; packing sets for RAW collection; HEPA filters; personal protective equipment. Results. Maps of spatial distribution of surface α-contamination in the building was constructed. We performed cluster analysis of data for zoning of contaminated surfaces. The decontamination factor for porous (brick, concrete), smooth (wood, brown tiles, laminate) and sticky (bitumen, mastic) surfaces was determined. Conclusion. The cluster analysis made it possible to identify 4 levels of surface α- and β- contamination, particles/cm2 · min: zone I - for α- above 50, for β- above 10,000; zone II - for α- 5-50, for β- 2,000-10,000; zone III - for α- no more than 5, for β- 2000; zone IV - corresponds to the background values of the workspace surfaces. The dry decontamination method revealed a high content of fine dust aerosol fraction deposited in the lungs. To increase the efficiency of dust suppression, water aerosol with droplet size of 100 - 400 microns and quartz sand with particle size of 100-200 microns were sprayed at the rate of 200-400 g per 1 m2. The decontamination coefficient depends on the coating material and the level of surface contamination: concrete - 91 to 97.8%; brick - 85-86%, wood - 38.8-53%; brownstone tiles - up to 29%; mastic - 22-28%; bitumen - 15.9-20%. To protect the personnel, radiation-hygienic rationing of PM10 and PM2,5 content is necessary. © 2019 Izdatel'stvo Meditsina. All rights reserved

Assessment of the volume activity of α-radioactive wastes on surface and specific contamination by portable γ-spectrometry method

The aim of the study is to evaluate the volume activity of radioactive waste (RW) by surface and specific alpha contamination using portable gamma-spectrometry. Materials and methods. Methods of rapid assessment of the content of α-emitting radionuclides in solid waste of various morphologies using gamma-spectrometers based on germanium detectors are considered. Computational methods for determining the effectiveness of radionuclide registration are presented. Results. The possibility of using portable gamma-ray spectrometry to assess the surface and specific activity of various materials contaminated with α-emitters (232Th,235U,238U,237Np,239Pu,240Pu and241Am) is shown. The calculated values of the registration efficiency of low-energy gamma-emitters obtained by modeling the spatial-energy parameters of the detector are given. To simplify the solution of this problem, the calculation program used 20 standard templates of various geometries (rectangular, cylindrical, conical, spherical, etc.). The main sources of error in the survey of contaminated surfaces, largesized equipment and building structures were investigated. Conclusions. The possibilities of portable γ-spectrometry for estimating the volume of RW based on the surface density of contamination of materials with radionuclides of uranium and transuranic elements are investigated. When using γ-spectrometer with a high-purity germanium detector with a range of γ-quanta extended in the low-energy region, radionuclides such as232Th,235U,238U, 237 Np,241Am were determined by their own radiation or by the radiation of their daughter products. The “problem” element is plutonium, for rapid evaluation of which it is proposed, in accordance with the radionuclide vector methodology, to use241Am, which accumulates during the β-decay of241Pu. According to calculations, the most likely value of the activity ratio239Pu/241Am for the object where the work was performed (scaling factor) varies in the range from 5.0 to 9.0. Based on the results of calculations and experimental studies, the parameters of the efficiency of registration of various α-emitting radionuclides by portable γ-spectrometers. It has been found that for germanium detectors with an absolute efficiency of registering a point source of 7÷15%, it is n×10–5 ÷ n×10–4%. © 2020, Institut meditsiny truda RAMN. All rights reserved

Regulação da embriogênese semática in vitro com ênfase do papel de hormonios endógenos

Different aspects of the in vitro somatic embryogenesis regulation are reviewed in this paper.work. A description of g General aspects, such as terminology, uses, stages of development and factors associated with the somatic embryogenesis, are described. is carried out. Although a brief description ofn the effects of the addition of different plant growth regulators to the culture medium wasis given, the article is centereds itself on the effect that the endogenous hormone concentrations in the initial explants and in the tissue cultures derived from them could play oin the induction and expression of somatic embryogenesis. It is significant that few to emphasize the low amount of systematic studies have been conducted, in this subject, in which different species and hormone groups were compared in cultures with and without embryogenic capacity. Moreover, the lack of correlation between the results presented in different studies the distinct works indicates that the hormone content of the cultures is not the only factor involved.Neste trabalho se faz uma revisão de diversos aspectos da regulação da embriogêneses somático in vitro. Vários aspectos gerais a este fenômeno tem sido discutidos, tais como a definição de terminologia, descrição de eventuais aplicações, seus estados de desenvolvimento e outros fatores associados com sua indução e expressão. Embora se faça uma breve descrição do efeito da adição de diferentes reguladores de crescimento ao meio de cultivo, o artigo está centrado no efeito que as concentrações hormonais endogênas nos explantes iniciais e nos cultivos in vitro derivados deles podem ter na indução e expressão da embriogênese somática. Tem de se fazer ênfase na pouca quantidade de estudos sistemáticos realizados neste tema que comparem em várias espécies e diferentes grupos hormonais em cultivos com e sem competência embriogênica. Finalmente, indica-se que a falta de correlação entre os resultados destes poucos trabalhos parece indicar que os conteúdos hormonais endôgenos não são os únicos fatores envolvidos neste fenômeno.Grman Academic Exchange Service//DAAD/AlemaniaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro para Investigaciones en Granos y Semillas (CIGRAS