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[en] Evaluation of the possibilities of uranium purification by the method of crucibleless zone melting using the C-701 and IEBZ-2 installations is carried out. The analysis of the metal for 17 metal and 5 non-metals microimpurities is made by the method of the spark mass-spectrometry. It is shown that the crucibleless zone melting is sufficiently effective for afterpurification of metal uranium. After two passes of the melted zone the amount of microimpurities in uranium sample decreased twofold in the average (from 0.8 to 0.4 at.%). The fact that the melted zone is hardy held with the surface forces and formation of chemical compounds films took place on the metal surface is the main difficulty in the process realization
[en] Statistical methods are useful tools to aid the recognition of patterns and extract information from a large amount of data available through resources such as earthquake catalogs. Visibility graph analysis is one of these relatively new statistical techniques that can be applied on data in the form of time series, and map them into a graph of nodes and connections, which makes it possible to use network theory for characterizing the original data. We present a study applying visibility graph analysis to a seismicity catalog for the Alaska crust and the Aleutian subduction zone. The catalog is gathered from the United States Geological Survey database, for the years between 1900 and mid 2017. A history of several earthquakes and a variety in seismic features, both near surface and at depth, make this region one of the richest areas to investigate possible seismic patterns and correlations. The focus here is on examining the previously suggested correlation between b value of the Gutenberg–Richter relation and the k–M slope from a visibility graph analysis. The visibility graph method defines a k degree or connectivity degree for each event according to its magnitude and position in time series. The k–M slope represents the slope of the regression line of these pairs of magnitude and connectivity degree, as a single number for each zone. We calculate the k–M slope for selected zones for Alaska and the Aleutians and add it to the data from previous worldwide studies and the results verify and improve the linear universal relationship between b value and k–M slope suggested by past studies, which indicates that the visibility graph analysis can work as an alternative approach for studying earthquake sequence.
[en] This data on the age of metamorphism of rocks of the Yelabuga zone and the geochronological data on detrital zircon from paragneisses of the same zone are presented, and their correlation with the ages of rocks from the Middle Volga megablock is made. The rocks of the Yelabuga zone and Middle Volga megablock have similar geochemical characteristics and degrees of metamorphism, but demonstrate the following differences: Paleoproterozoic metamorphism was clearly expressed in the studied rocks of the Yelabuga zone, which contrasts to rocks of the Middle Volga megablock, where no metamorphism of this age is manifested. The study of the U–Pb isotopic system in external zones of zircon crystals from the Yelabuga deformation zone suggests that rocks underwent two stages of metamorphism, 1.99 and 1.95 Ga ago.
[en] The geometry of supposed coupling zones in the Kamchatka subduction zone is determined by the earthquake size distribution based on ealier revealed relationship between its shape and rate of inelastic deformations. In the areas of higher aseismic slip, a break of linearity in earthquake size distribution is observed owing to the deficit of large earthquakes. Zones of higher coupling between the oceanic and continental plates are characterized by an excess of large earthquakes and an inverse bend in the earthquake size distribution. The mapping results of the bend value agree with the coupling zones distinguished from satellite geodetic data and inversion of marigrams.
[en] In the process of zone melting, effective distribution of additions in the main material took place. To determine the factor of effective distribution it is suitable to use radioisotopes as an indicator addition. Distribution of antimony-124 in iron was studied. Isotope content has been determined in the quantity nearly equal to 10-3 - 10-5%. Estimation of the effective distribution factor was done according to the concentration curve, plotted on the base of the activity magnitudes, having been measured by the slot method. Magnitude has been found of the-124 distribution factor in iron Ksub(ef) = 0.775. By the analogous method, distribution of antimony-124 and silver-110 in cobalt and copper was investigated
[en] Complete text of publication follows. The Betic Chain is a WSW-ENE oriented Alpine Chain located in the western end of the Mediterranean. Together with the African Rif Chain it forms an arc shaped orogenic belt surrounding the Alboran Basin, formed as a consequence of the convergence between the African and Iberian plates since the Late Cretaceous. The Betics are divided into the External Zone, formed by sedimentary rocks of the former Iberian Massif margin, and the Internal Zone, which is a stack of three metamorphic complexes that were emplaced over the External Zone. Both Internal and External parts of the Betic Chain overthrust the Iberian Massif. The Betic Chain has been the focus of numerous geophysical studies pointing at the study of its crustal and lithospheric structure, showing its complexity. The 3D geoelectrical model obtained from a previous magnetotelluric study had shown the presence of an upper- middle crust conductor in the Internal Zone, interpreted as high conductive mineralisations. New magnetotelluric data has been acquired in the area by the University of Barcelona in order to check whether this conductor body has continuity towards West or not, and to better constrain the structures imaged in the previous model, using 3D inversion modelling. Preliminary results show that the conductive body under the Sierra de los Filabres has no clear continuity to the West under Sierra Nevada. A new conductor appears West of Granada. Its depth and conductivity are being constrained through several sensitivity tests. Some other new conductive and resistive bodies appear at the Western part of the model, which can be associated to geological units such as the Alpujarride Complex or the Granada Basin. Moreover, new long period magnetotelluric data is being processed in order to characterize the deepest structure in the area.
[en] Broadband and long-period magnetotelluric data were acquired over the northern part of the Cambay rift zone along an east–west profile ~ 200 km in length. The decomposed TE- and TM-mode data were inverted using a 2-D nonlinear conjugate gradient algorithm to obtain the lithospheric structure of the region. A highly conductive (~ 1000 S) layer was identified within the Cambay rift zone and interpreted as thick Quaternary and Tertiary sediments. The crustal conductors found in the profile were due to fluid emplacement in the western part, and the presence of fluids and/or interconnected sulfides caused by metamorphic phases in the eastern part. The demarcation of the Cambay rift zone is clearly delineated with a steeply dipping fault on the western margin, whereas the eastern margin of the rift zone gently dips along the NE–SW axis, representing a half-graben structure. A highly resistive body identified outside the rift zone is interpreted as an igneous granitic intrusive complex. Moderately conductive (30–100 Ω-m) zones indicate underplating and the presence of partial melt due to plume–lithosphere interactions. .