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The geochemical regional specialization of the behavior of rare earth elements (REE) in the soils of Sochi, manifested in the predominance of REE of the middle group, has been established. The enrichment by the middle group of REE is inherited from the rocks (mainly clayey mudstones) of the territory. At the same time, the features of the distribution of REE, characteristic of natural soils, are not violated for soils formed under the conditions of technogenesis. This indicates that the pollution of urban soils is determined by a natural and technogenic factor. The sources of pollution are man-made sites and talus, which lack a soil-vegetation layer, including those recently formed during the preparation for the 2014 Winter Olympic Games and composed of the same material as the parent rocks, but significantly crushed and, accordingly, subject to active weathering. In mosses of the urban zone, in the eluvial landscape, the predominance of the middle group of REE is not observed. However, as we move down the slope, the REE distribution curve relative to the North American shale standardization becomes similar to the similar graph for soils and rocks. The relationship between the accumulation of elements in mosses, and in soils and underlying rocks is revealed when considering the features of fractionation of REE in mosses of the super-aquatic landscape.

Introduction. Currently, the development of safe helicopter landing systems as the most complex and dangerous stage of a flight is one of the priority tasks. A significant number of companies in Russia and abroad are engaged in its solution. Landing on unprepared (unequipped) sites with snow-ice cover may be caused by the need to deliver units, cargo and ammunition in combat conditions, search and rescue operations, evacuations of victims, etc. A key factor for a landing decision is information about the height of snow and about the depth of ice cover. In the paper remote identification of the state of snow-ice cover, excluding the need to present any person (crew member or rescue worker) on a landing site is proposed.Aim. To develop a method for the remote identification of the state of snow-ice cover used to determine the possibility of a helicopter - type aircraft safe landing on a reservoir with snow-ice cover.Materials and methods. Numerical simulation of echo signals Fresnel reflection coefficients polarization ratio was realized in MatLab. Vertical and horizontal polarizations in the range from 25 to 45 degrees were simulated.Results. Intervals of polarization relations correspond to the interval density of snow-ice layers for fixed angles. For example, when θ = 34 for dry snow ρds = 100…500 kg/m3 (ε'ds = 1.162…1.984) – Prm = 5.6915...3.3266, dry firn ρdf = 500…700 kg/m3 (ε'df = 1.984…2.51) – Prm = 3.3266...2.8311, dry ice ρdi = 700…913 kg/m3 (ε'di = 2.51…3.179) – Prm = 2.8311...2.4753. A layer reconstruction inverse problem was solved by indirect determining of complex relative permittivity of each successive underlying layer with 10-2 real part resolution. The identity of the obtained characteristics of snow-ice layers with calculated (standard) values was established.Conclusion. Remote identification of components of a snow-ice cover structure allows one to automate the process of evaluating of landing possibility. Thereby it reduces a decision-making time and increases a level of safety. In contrast to the known methods of identification of the surface layer the identification of multilayer medium layers was carried out.

Matua is a volcanic island located in the central part of the Kurile-Kamchatka island arc. Its greater north-western part is occupied by the edifice of Sarychev Peak Volcano, which is one of the most active volcanoes in the Kuriles. The south-eastern part of the island is an ancient abrasion-accumulative terrace, which base is formed by weakly dislocated Pliocene-Eopleistocene volcanic-aqueous complexes overlapped with marine deposits and solid soil-pyroclastic cover. Besides, Matua Island is an area with a unique anthropogenic landscape shaped by the Japan army as a result of the construction of elaborated military fortifications in the first half of the 20th century. The paper provides the results of GPR investigation of the soil-pyroclastic cover on Matua Island. The survey included detection of hidden posterns, large-scale cavities and a GPR inspecting of fortifications areas. The results of GPR sounding are compared to geological profile data, which provide records for the explosive activity on the island over the period late Pleistocene to Holocene.

Purpose: to determine a change in the soil properties of a complex cover influenced by irrigation for developing the appropriate measures to prevent their further degradation. Materials and methods. The object of research is brown semi-desert soils in combination with solonetzes located in the region of the Caspian lowland. Soil samples and data assessment analysis was carried out according to generally accepted methods. Mathematical data processing was carried out according to B. A. Dospekhov. Results. Irrigation carried out regularly with fresh water for 6 years with an average irrigation rate of about 5400 cubic meters per hectare contributed to the leaching of water-soluble salts in the soil layer of a complex cover of 0–40 cm. The decrease in the total salt content in this layer was 13 %, in solonetzes – 46 %, and in the layer of 40–60 cm, on the contrary, their accumulation is observed in the amount of 9 and 18 %, respectively. At the same time irrigation with water of class II by hazard degree of sodium alkalinity increased the content of exchangeable sodium and magnesium in the soil adsorption complex in the 0–40 cm layer of brown soils by 50 and 26 %, respectively, and in solonetzes by 60 and 21 % (in the meter layer, respectively, 25 and 9; 25 and 11 %). The number of water-resistant aggregates in the layer of 0–40 cm in both soils decreased by 20 %, and the soils became denser. As a result, water permeability from brown soils surface decreased by 33 % and in solonetzes – by 27 %. The humus content in the 0–40 cm layer of brown soils decreased by 10 % and on solonetzes – by 20 % of the initial content. After 6 years of irrigation, its amount was 90 and 80 %, respectively, which indicates the presence of weak and medium dehumification. Conclusions. The detected changes in properties of the soils studied indicate the need for chemical reclamation, which eliminates the salinity and compaction as well as the development of appropriate measures that contribute to the humus accumulation.

Based on the consideration and analysis of different approaches to obtaining data for constructing a digital elevation model and types of three-dimensional surface representation, the choice of the most optimum technique for construction and visualization of three- dimensional model of the volcano-sedimentary cover of the Streltsovskaya caldera in Eastern Transbaikalia has been substantiated. The creation of such model determines the need for detection, identification and monitoring of processes, phenomena and factors of natural and anthropogenic origin at uranium deposits of the same named ore field, which are developed by underground way in difficult mining and geological conditions. To solve this problem, modeling of the daylight surface relief and the basement roof has been carried out on the basis on remote sensing data, geophysical studies, cartographic materials vectorization and processing results. The space between the constructed surfaces due to the algorithm for creating closed framework of surfaces has been transformed into a new object representing three-dimensional volumetric model of the caldera volcano-sedimentary cover. The received results allow creating a predictive model of the tectonic and dynamic state of the Streltsovky ore field rock massifs for the deposits development and mine workings design.

Features of the viscous-plastic material flow through the screw channel are studied. A promising direction in this case is the transport models determined by the hydrodynamics of the phase transition. The author also analyzed the effect of dimensions on the flow rate of a viscous-plastic material. The material situated in the channel of the rotating auger and bounded by the fixed body will start to move in a translational motion along the channel due to the shear deformation that appears in it, this is where a forced flow appears. The main parameters that determine the volume flow rate are the depth and width of the channel, the diameter of the screw and the frequency of its rotation. A necessary condition for the existence of this flow is the persistence of shear stress in the material, which is possible only if the material has a certain viscosity. The condition of the return flow is the excessive pressure created by the resistance of the head. We assume the case when in these conditions the auger does not move. Then, under the action of pressure from the side of the head, the material will flow from it along the screw channel – in the opposite direction. The volume flow rate of the counter-flow also depends on the depth of the channel, on the diameter and length of the screw, on the viscosity of the material and on the pressure in the head. In practice, however, there is never a countercurrent in the auger channel, and the head pressure exerts a kind of limitation on the direct flow, which is theoretically viewed as a countercurrent, and the productivity of the screw supercharger is the total flow of the two flows. To account for the geometry of the channel, the author developed a mathematical model of the velocity head in a rectangular channel. The resulting equation makes it possible to determine the shear stress in terms of the shear rate of the material. Taking into account the symmetry and linearity of the velocity distribution in the channel with respect to its midpoint, an equation is obtained for the distribution of the shear rate along the height. The dependence, obtained as a result of the analytical solution of the two-dimensional Poisson equation, makes it possible to simplify considerably the calculation of the discharge-pressure characteristics of the extruder part of the screw presses for pressing vegetable oils with respect to the required screw rotation speed.

Рассмотрена нестационарная задача об изгибно-гравитационных волнах на поверхности замороженного ледового канала, вызванных движением внешней нагрузки. Задача решается методом преобразования Фурье вдоль канала и разложением прогибов льда по модам бегущих изгибно-гравитационных волн в канале. Предложен алгоритм, позволяющий привести решение, полученное с помощью обратного преобразования Фурье, к аналитическим формулам в виде суммы стационарных и нестационарных прогибов при конечных временах в системе координат, движущейся вместе с нагрузкой. Исследована эволюция прогибов во времени для разных скоростей движения нагрузки. Показано, что при увеличении времени решение для нестационарных прогибов ледовой пластины выходит на установившийся режим в системе координат, связанной с нагрузкой. Исследовано влияние коэффициента затухания на образование волн., The non-stationary problem of a moving external load along the surface of a frozen channel is studied in this paper. The channel has a rectangular cross section and is filled with an ideal fluid. The ice cover on the surface of the liquid is modelled by a thin elastic or viscoelastic plate (Kelvin-Voigt model), which is frozen to the channel walls. The external load is modelled by a local pressure moving at a constant speed along the channel. The ice-fluid-load system initially is at rest. The flow caused by both the moving load and the ice deflection is supposed to be potential. The problem is solved using the Fourier transform along the channel and by the method of normal modes. The presence of the channel walls and boundary conditions on them lead to an infinite (countable) number of dispersion relations and critical speeds for the hydroelastic waves propagating in the channel. Depending on the speed of the load, the form of the ice cover oscillations has one of two main cases. When the load moves at a speed lower than the first critical speed, the ice deflection is localised in the vicinity of the load. When the load is moving at supercritical speed, a system of hydroelastic waves propagating from the load is formed. The number of these wave systems is finite and depends on the relation of the speed of the load with the critical speeds for the channel. It is shown that as time increases, the solution for the ice deflection converge to a steady state in the coordinate system moving with the load. The influence of the retardation time on the formation of the ice deflections is investigated., №2(24) (2019)

The dynamic-thermodynamic model of the ice cover evolution is used for operational 5‑day ice forecasts in the Russian Arctic seas and to obtain some statistical estimates of the ice cover state. The model is a numerical realization of the heat budget and the motion balance equations for sea and ice cover with appropriate boundary conditions. The statistical processing of the data resulted in revealing characteristics of seasonal and spatial variability of the ice compression in the Barents and Kara Seas.

The rather low cost of material and reliable manufacturing processes, including increasingly recognized 3-D technologies, cause broad application of products from plastic. At the same time, rather low strength properties of plastic in comparison with metal alloys require an evidence-based approach to design of products from plastic. Taking into account the relaxation properties of plastic details used under thermo-mechanical loading conditions is an issue of special attention The relaxation of stresses leads to decreasing level of internal stresses and emerging irreversible plastic strains. The stress-strain state is defined by a type of loading and significantly depends on temperature and time factors. For calculations, it is necessary to have results of material tests for creep. In a concrete detail the stress-strain state is not uniform, especially in the area of stress concentration. Cuts and internal corners can act as the stress concentrators. Concentration of stresses leads to the fall-off strength of plastic details, in particular when heating and at high-speed strain. In zones of stress concentration the phenomena of creep and stress relaxation are most significantly shown. The stress relaxation is cause of design efficiency loss. The process of stress relaxation depends on the material properties, on the detail time under stress, and on the level of strains. To increase efficiency, other materials are used, strain time of a detail and level of strains (stresses) in a design are reduced.

Mathematical model of a new icebreaker device is worked out using the theory of small elastic deformations and numerically approved.

During geological engineering research for new building of the Novosibirsk state university a horizon of ground settlement classified by the standard analysis as sandy silt loam has been found. Genesis of this ground and its distribution remains obscure. Our study of grains size, electric and rockmagnetic properties of those materials shows that they are represented by inter-bedding of sandy layers of different grain size and horizons of fossil soils. The upper part of the section up to the depth of 0,8-1,0 m sufficiently differs from the lower part by abnormally high specific electric resistance, opposite character of correlation between grain size and roc k- m agnetic parameters that can be caused by a continuation of modern soil-forming processes. Our results recommend geological-geophysical studies of soils for the given territory with sampling interval in boreholes 0,5 m.