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The paper presents the results of studies of diamonds from Early Jurassic sediments making up the Nyurbinskoe buried placer of the Nakyn kimberlite field, unique in diamond reserves. The main task was to identify the patterns of diamond distribution in the deposits of the Dyakhtar strata (lower deposit) and the Ukugut Formation (upper deposit) within the placer. A comparative analysis of the typomorphic features of diamonds from the upper and lower deposits of the placer was carried out. Variations in the contents of crystals with certain properties that form the image of a diamond-bearing geologic object have been revealed. The zonal distribution of diamonds by characteristics in sedimentary deposits, regardless of their age, has been established. The properties of diamonds and their associations change within the placer, which is due to their redeposition during the Early Jurassic sedimentation.

Magnetic viscosity is one of the aftereffects inherent in geologic materials. This phenomenon consists in the time lag of changes in the magnetic characteristics of ferromagnetic materials relative to changes in the external magnetic field. Magnetic viscosity in rocks is associated mainly with the magnetization of superparamagnetic particles of ferrimagnetic minerals. In the transient electromagnetic method, magnetic viscosity is manifested as a slowly decreasing voltage induced in a receiving loop or, in some cases, as a nonmonotone transient voltage response. Eddy currents and viscous magnetization arise and decay independently of each other; therefore, the induction transient response measured with a fixed-geometry TEM array gives no way of finding the vertical distribution of magnetic viscosity. To find this distribution requires geometric soundings. At late times, the voltage induced in the receiving loop due to the magnetization decay is vastly larger than that induced by the eddy currents. Therefore, the contribution of magnetic viscosity to the total transient response limits the sounding depth of the transient electromagnetic method.

The geological study of the Mesozoic sections of the New Siberian Islands archipelago and Asian coastal sections of the Arctic Ocean plays a key role in tying the results of comprehensive studies with seismic data on the Laptev Sea shelf and the western part of the East Siberian Sea. Therefore, it is extremely important to improve the subdivision of the Triassic system of the New Siberian archipelago and to define the position of the system in the structure of the Laptev Sea shelf sedimentary basin. The results of our study were used to improve and refine the lithostratigraphic subdivision of the Triassic in the study area and to recognize a distinct interregional stratigraphic marker, i. e., the Czekanowski Formation (lower Olenekian). In terms of genetic, structural, and sedimentological features, the Triassic strata were grouped into two groups: the Reshetnikov Group (Induan-upper Ladinian) and the Svetlaya Group (Ladinian-Rhaetian), reflecting major stages of sedimentation. For the Triassic of the eastern Laptev Sea shelf and adjacent onshore areas, the facies zonation scheme has been developed and refined on a unified basis. Based on their structure, the Phanerozoic sections of the study area can be considered as a part of the intermediate structural stage of the Laptev Sea plate at the margins of the Siberian craton.

Numerous epithermal Au-Ag deposits and ore occurrences of the Chukchi Peninsula are localized in the Cretaceous Okhotsk-Chukotka (OCVB) continent-marginal and Late Jurassic-Early Cretaceous Oloi (OVB) island arc volcanic belts and in Early Cretaceous postcollisional volcanic troughs. Volcanotectonic depressions, calderas, and volcanic domes control the location of the deposits. The orebodies of the deposits are quartz-adularia veins, sometimes en-echelon ones forming extending vein zones, as well as isometric and linear stockworks. The auriferous veins of most deposits display complex breccia-crustification structures. The vein ores have rhythmically and colloform-banded structures, with a predominantly fine distribution of ore mineral grains, often with banded clusters of ore minerals (ginguro). Native gold is of low fineness; the dispersion of this index varies from low to high. Acanthite is widespread in the ores. Its highest contents are specific to deposits with the repeated redistribution of substance (Kupol, Corrida, and Valunistoe). Based on the results of mineralogical studies, most of the epithermal Au-Ag deposits of the Chukchi Peninsula can be assigned to the Se type. The ores of some deposits (Valunistoe, Dvoinoe, etc.) contain both Se and Te minerals. The telluride-richest sites of the Sentyabr’skoe and Televeem deposits are far from the main orebodies. Most of the Chukchi epithermal Au-Ag deposits have many common characteristics (low and moderate temperatures of fluids, low fluid salinity, domination of carbon dioxide over methane, etc.) typical of low-sulfidation deposits. The maximum temperatures and salinity are specific to fluids in the Central Chukchi sector of the OCVB and in the Baimka zone of the OVB, and the minimum ones are typical of fluids in the East Chukchi flank zone and inner zone of the OCVB. The average salinity of mineral-forming fluids in the inner zone of the OCVB is half as high as the salinity of fluids in the East Chukchi flank zone of this belt, although the sulfate content is higher. At the same time, the fluids in the inner zone of the OCVB are richer in carbon dioxide and bicarbonate ion than the fluids in the East Chukchi flank zone of this belt. The fluid inclusion data permit the Vesennee deposit (Baimka zone) to be regarded as an intermediate-sulfidation one and suggest the presence of epithermal high-sulfidation deposits in the inner zone of the OCVB.

The paper presents the U-Pb age of zircons and the geochemical and isotope characteristics of granitoids from the Kitoi block (Sharyzhalgai uplift, southwestern Siberian craton). The studied granitoids compose different-scale vein bodies. According to the structural relations among the rocks and their U-Pb zircon ages, there were three stages of early Precambrian granite formation: ~2.99, 2.54, and 1.88 Ga. The Neoarchean and Paleoproterozoic granites contain inherited zircons dated at ~2.97-3.00 Ga, which are close in age to magmatic zircons from the Mezoarchean granite-gneiss. The Kitoi granitoids of different ages show similar enrichment in SiO₂, K₂O, and incompatible trace elements. In trace element composition and crystallization temperatures the Mesoarchean granite-gneisses are similar to A-type granites, while the Neoarchean and Paleoproterozoic granitoids, to I-type ones. The inherited ~2.97-3.00 Ga zircons and narrow range of model Nd ages ( T _Nd(DM) = 3.0-3.3 Ga) indicate that the Neoarchean and Paleoproterozoic granitoids formed through the recycling of the Mesoarchean crust. The Neoarchean (~2.54 Ga) and Paleoproterozoic (~1.88 Ga) stages of granite emplacement in the northwest of the Kitoi block correlate with the formation of granitoids and high-temperature metamorphism in the Irkut block and the border zone between the two blocks. The subsynchronous granite formation and metamorphism (~2.54 Ga) give strong evidence that the amalgamation of the Kitoi and Irkut blocks resulted from collisional orogeny in the terminal Neoarchean.

The aim of the work is to analyze the existing and used methods of direct molecular modeling of physical processes and phenomena. In particular, methods of molecular dynamics, Brownian dynamics, direct statistical Monte Carlo modeling, and stochastic molecular modeling are discussed. In all cases, the main features of these methods, the accuracy of modeling and development prospects are analyzed. Examples of solving original problems, in particular, modeling of gas transfer coefficients in the volume and nanochannels are considered.

The article presents the results of numerical simulation of the boundary layer of air on a heated surface in the presence of weak acceleration. The numerical model consists of a system of Prandtl equations describing dynamic and thermal processes in the boundary layer, and a κ-ω-γ turbulence model that allows reasonably simulating the laminar-turbulent transition and turbulence suppression. Finite-difference methods were used to solve differential equations. For some calculated cases, the turbulence model was switched off in order to obtain parameters of a known laminar flow. Modeling has shown that in the considered flow conditions, the occurrence and development of a local laminarized region near the wall is possible. In this case, the boundary layer includes the near-wall laminar and external turbulent sections. This nature of the flow leads to a level of friction and heat exchange that correspond to the intermediate flow relative to laminar and turbulent flows under the same conditions.

Known approaches to the determination of flow parameters in the test section of impulse wind tunnels are analyzed, and ways towards their improvement are outlined. An algorithm for calculating flow parameters in short-duration supersonic high-enthalpy wind tunnels using the experimental values of pressure in the prechamber, the total pressure behind the normal shock, and the flow velocity and stagnation temperature as a function of time, is developed. It is shown that the results of measurements and calculations using the developed algorithm for determining flow parameters fairly well comply with the calculations of flow parameters based on the gas-dynamic relations taking into account the losses of heat in the working path of the wind tunnel.

The paper discloses the study of flow crisis in the Ranque-Hilsch vortex tube with a squared cross-section channel. Previous studies have found the conditions for developing the hydraulic crisis for air flow in this type of tube. The crisis phenomenon is related to the event when the longitudinal velocity at the nearwall vortex-circulation zone interface approaches the value of velocity for spreading centrifugal waves along this boundary. The paper presents and discusses the new detail results in measuring the kinematic parameters of the crisis flow, including the parameter of velocity pulsation. The evidences of a hydraulic jump neat the exit of the swirl flow to the tube working channel.

The formation of circulation vortex cells in a liquid medium of a gas-vortex bioreactor has been experimentally studied. The study was carried out in an industrial glass bioreactor with a volume of 10 liters and a reactor vessel diameter D = 190 mm. The vortex motion of air was generated by a paddle wheel (activator) when 50 and 80% of the reactor vessel was filled with the model medium. A 65% water solution of glycerol with density ρ = 1150 кг/м³ and kinematic viscosity ν = 15 мм²/с was used as a model medium. To observe the pattern of vortex motion, the method of particle image velocimetry (PIV) was used. It is shown that when the activator rotates, the meridional and circulation motions of the liquid occur simultaneously. Regularities of the vortex motion of the model medium are determined depending on the reactor filling and the intensity of activator rotation. It is found that the cells of centrifugal circulation appear under the interface; with an increase in the activator rotational speed they develop into the depth of the reactor. It is established that centrifugal circulation of liquid develops similarly as it takes place in a closed vortex flow of one liquid and in a system of limited vortex motion of two immiscible liquids.