Home – Home – Jornals – Earth’s Cryosphere 2024 number 4

For spaces of object representations with given distances, the lower bounds to the error probability of object classification subject to the fixed values of the amount of processed information are investigated. The bounds are defined by the strictly decreasing functions of the minimal average mutual information between the submitted objects and the estimations of their classes depending on the error probability. So, the inverse functions yield the minimal error probability for any fixed value of the average mutual information. For spaces of tree-structured and vector-based object representations, numerical realizations of the bounds are calculated. It is shown that the lower bound to the error probability is lower in the space of vector-based representations as against the similar bound in the space of tree-structured representations. Also, a possibility of decreasing the bound to the error probability by combining object representations with various distance functions is demonstrated.

This work proposes new algorithms for combining superpixels into segments using a “greedy” strategy and a combined quality measure that includes two components: a measure of information redundancy and variation of information. The “greedy” strategy was previously used by the author to speed up image segmentation from the condition of minimum information redundancy, and a two-component information quality measure was used in the problem of combining different segmentation maps. The joint use of the “greedy” strategy and the combined quality measure in new algorithms is aimed at accelerating the generation of segmentation maps and improving their quality through a compromise between the requirements of minimizing the number of informationally important segments and minimizing the information difference between the original images and the generated partitions. A computational experiment on test images shows that the proposed algorithms can speed up the segmentation process compared to the method based on minimizing information redundancy previously used by the author and improve the information characteristics of the resulting segmentation maps.

The paper proposes a method for protecting 3D printed products made using the FDM technology from unauthorized copying. This method is based on the controlled deviation of the trajectory of filament application on a flat section of the surface layer of the product. The amount of deviation of the line trajectory is determined by the built-in security mark, which plays the role of a watermark. Changes made in this way are difficult to detect visually and even more difficult to automatically read when scanning the shape of a 3D product and subsequently reproduce it when creating its copy. In this case, verification of the authenticity of a product by detecting a security mark can be performed by shooting the product with a digital camera and specialized processing based on spectral analysis and narrow-band filtering.

Experiments are conducted on the use of mathematical processing methods for an expanded comparative analysis of the composition of biomaterials and brefomatrices. The linear discriminant analysis and ROC analysis are used as the main mathematical methods for processing the Raman spectra of the biomaterials under study. It is found that demineralized biomaterials from juvenile dentin are less antigenic compared to brefomatrices.

The work is devoted to studying the possibility of increasing the accuracy of measuring the coordinates and brightness of small-sized moving objects in a sequence of images formed by a scanning multi-row photodetector. The measurement is based on approximating the object image with a function whose parameters are the object brightness and the shift of its projection center relative to the nodes of the array of photosensitive cells (PSC) of the receiver. The approximation quality criteria are, on the one hand, the root-mean-square difference between the object image and the approximating function, and on the other hand, the spread of its coordinates and brightness estimates depending on the position relative to the center of the photodetector cell in a series of images. Several of the most popular functions commonly used to approximate a discrete image of a small-sized object are compared on a series of images obtained by projecting an illuminated small-diameter diaphragm into the plane of the photosensitive layer of the receiver. It is shown that, even with a sufficiently high level of random noise, the use of an approximating model allows one to estimate the coordinates of an object with a root-mean-square error not exceeding 20% of the PSC lattice step.

The article proposes a technique to identify the location of the round-shaped object in the image and to calculate its diameter. The technique is based on calculating the cross-correlation values of the analyzed image and several specific pattern images and on the subsequent analysis which of the patterns and for what its position relative to the inspected image is the most suitable one. The technique allows one not only to calculate the object size and coordinates, but also to determine the actual presence or absence of the object in the field of view. The feasibility and practical applicability of the technique are shown using an example of inspecting the ball-type wire bonding to the surface of a die in integrated circuits. The algorithm can be used as a part of software for non-destructive testing systems intended to inspect semiconductor products during their manufacturing before casing them. In particular, the algorithm allows one to check if there is a ball-type wire bonding at the place where it should be and to determine if both the location of the ball and its diameter are acceptable.

This article explores the application of the transformer architecture for encoding states in reinforcement learning algorithms. A new approach is presented, which integrates transformers with existing methods, such as Soft Actor-Critic (SAC), to enhance their performance and generalization ability. The results of experimental studies show that the proposed approach can improve learning in complex tasks of acquiring movement skills in a three-dimensional space.

The work is devoted to the experimental study of the effectiveness of methods of classification of green vegetation and camouflage materials according to their spectral characteristics. The studies are performed using real spectral data obtained on a multichannel spectrograph based on a dispersing element and a multi-element CCD ruler in the visible and near-infrared wavelength range. A technique is proposed for processing a set of spectral data in order to form a representative system of features and subsequent application of adaptive threshold algorithms for detecting objects. The effectiveness of using vegetation indices calculated for spectral channels with different widths and at different positions of the central wavelength as signs for classifying types of materials is investigated. Special attention is paid to the detection of differences between fresh and anthropogenic vegetation. It is experimentally shown that both two-channel and three-channel indices can be used as informative features in the classification of objects.

The purpose of this work is to improve the accuracy of measurements of the optical rotation angle (ORA) by analyzing the effect of the adjustment error of the differential phase polarimeter analyzer. The paper presents a scheme of a differential phase polarimeter used for the study of optically active substances. To analyze the effect of the alignment error of the rotating analyzer on the ORA measurements results, mathematical modeling of the process of forming an informative signal in the presence of a deviation from the perpendicular plane of the analyzer relative to the axis of radiation propagation is applied. The results of the study of the influence of the adjustment error on the accuracy of restoring the phase difference of two harmonic signals are presented. The results obtained make it possible to develop requirements for the adjustment of the elements of the differential phase polarimeter to increase the accuracy of the ORA measurements.

The dynamics of effective and physical (geometric) shrinkage of a holographic photopolymer material is studied by measuring the evolution of transmission spectra of volume reflection holograms during their recording. It is shown experimentally for the first time that physical shrinkage occurs to a significant extent already at an early stage of hologram formation, when its diffraction efficiency is insignificant (less than 0.05). It is established that the effective shrinkage values at the end of the exposure for small and large grating periods differ significantly, while the physical shrinkage is approximately the same. For the grating samples studied, the average refractive indices before and after exposure are estimated. A method and device for measuring the shrinkage dynamics of reflection photopolymer holograms have been developed, ensuring the minimal errors in estimating the shrinkage parameters. The research results may be useful for deepening the knowledge about the nature of hologram formation in photopolymer materials, as well as for practical use in the development of holographic elements and devices based on them.

The method of calibration of scales with an irregular structure typical for absolute angle encoders based on pseudo-random codes has been developed and tested. The calibration results at a level of ±2.2ʺ with an uncertainty of ±0.5ʺ, characteristic for the measuring and diagnostic unit AE.1686 used, are experimentally obtained. The reliability of the results of calibration of irregular scales is confirmed by the identity of the curves obtained when comparing them with the calibration curve of a regular scale formed at another radius in a single technological cycle together with one of the controlled irregular scales.

A fundamentally new model of an optical switch with decentralized control is proposed. The advantages of the proposed switch are the absence of optoelectronic conversion of the information signal and the possibility of constructing scalable circuits of low complexity. The switch circuit includes the following main elements: electrically controlled switch elements based on lithium niobate, Bragg filters, optical valves, focusing systems, a control lens system, and a local system for generating control signals. The calculation of the optical devices of the switch shows the possibility of its implementation and operation in the range of 1310-1460 nm for transmitting control signals and 1550 nm for the information signal to ensure interaction between data center devices.

The development of acousto-optical tunable filter with a synthesized spectral transmission characteristic is presented. The wide-aperture (wide-angle, tangent) geometry of acousto-optical tunable filters widely used in modern hyperspectral systems is considered. It is shown that they can be described with a single-coordinate model of acousto-optic interaction. The relationships between the driving radiofrequency signal characteristics, the parameters of the acoustic wave forming the grating, and the spectral transmission function of the acousto-optical filter are determined. The fundamental limitations on the spectral transmission function characteristics are revealed. In a linear transmission approximation, the deduced relations describe the operation of an acousto-optical filter with an arbitrary law of amplitude and frequency modulation of the driving signal. The results are applicable for development of acousto-optical spectral systems with a controlled transmission function.

The problem of determining the optimal initial composition of the reaction mixture is formulated in general terms. A method for solving this problem based on the simulated annealing algorithm is described. Computational experiments are conducted for the Michaelis-Menten enzymatic reaction and the aminomethylation of thiols. Parameters for the efficient operation of the algorithm are selected. Using the proposed method, the optimal initial composition of the reaction mixture ensuring the maximum yield of the target product is identified. An analysis of the effectiveness of this algorithm is presented by comparing it with the results obtained from other optimization methods.

Laser remote sensing of cirrus clouds is accompanied by the problem of taking into account the multiple scattering of radiation, which influences the reliability of measurement interpretation. The contribution of multiple scattering of radiation to echo signals of a space-borne lidar is estimated. The non-stationary problem of laser pulse propagation in continuous cirrus clouds with separation by scattering multiplicities is solved by the Monte Carlo method at different values of the optical-microstructural characteristics of clouds (optical thickness and shape and size of ice particles) and lidar parameters (distance from the sensing object, radiation divergence, and field of view angle of the receiver). Numerical experiments were carried out taking into account the permissible range of the parameter for operational or promising space-borne lidar systems. The features of the formation of the return signal when aerosol and Rayleigh particles, as well as the underlying cloud layer, are introduced into an atmospheric model are discussed. The simulation results indicate the high sensitivity of the part of an echo signal caused by multiply scattered radiation to the parameters under study, which should be taken into account when formulating and solving inverse problems.

The study of the field of total ozone column (TOC) is one of the important problems of atmospheric optics. In this paper, the spatial distribution of TOC over the Russian territory is analyzed based on Aura/OMI (Ozone Monitoring Instrument) data. The observation results for individual areas (points) are presented in the form of TOC time series, which cover the observation period from January 2005 to December 2022. Integral (excluding seasonal variations) latitude-longitude features of TOC distribution over the territory under study are revealed; correlation coefficients between the TOC series for different points are calculated; their relationship is studied depending on the distance between the points; the spatial autocorrelation function is derived and the sizes of spatial inhomogeneities of the TOC field are estimated. The spatial mismatch of the data is analyzed using a parameter which is a measure of the standard deviation from the average mismatch. The results of the work provide an idea of the scale of the spatial correlations in the TOC field and can be used for clarifying the optically active component of the atmosphere when developing weather and climate change prognostic models.

The electric field of the atmosphere, along with electrical conductivity and ionization of air, is the main characteristic of atmospheric electricity, which is a set of electrical phenomena occurring in the atmosphere, including in clouds and precipitation. There is a close connection between the intensity (potential gradient) of the atmospheric electric field and the topography and landscape of an area and meteorological parameters. A disruption of the normal electric field, characteristic of fair-weather conditions, occurs during the formation and development of clouds, precipitation, thunderstorm, etc. In general, the variability of the electric field is determined by a number of individual or combined factors, both of global and regional (or local) character. Therefore, studying and understanding the functioning of the Global Electric Circuit and its local variability seems to be a relevant scientific problem, especially in the context of the modern climate change. The variability of the electric field potential gradient and meteorological parameters is analyzed in this work based on long-term observations in a large urban settlement. The analysis shows a pronounced dependence of the potential gradient on the wind direction in fair-weather conditions, especially in winter, associated, we believe, with aerosol transfer. We also found that the variability of the surface electric field, including seasonal and daily variations, under all meteorological conditions significantly differs from the variability under exceptionally fair-weather conditions. The results are in good agreement with similar studies at other observation sites located near large populated areas, and are of interest for simulating the state and variability of the Global Electric Circuit depending on various physiographic and meteorological conditions.

The relevance of studying the dynamics of ozone concentration is due to the fact that at high concentrations it is a potent poison and a powerful oxidizer that extremely negatively impacts both biological objects and the environment. Based on the monitoring data, the paper examines the distribution of tropospheric ozone in Russia in 2023 in the surface air layer, as well as its vertical distribution based on the results of aircraft sounding. It is shown that the maximum allowable daily average concentrations established by the domestic hygienic standard, maximum single, daily average, and annual average, were exceeded at all measurement points. The current situation necessitates widespread public awareness of the results of monitoring and the development of environmental measures to reduce the concentration of ozone and its precursors in the surface air layer.

Expansion of the functional capabilities of lasers in general and metal vapor lasers in particular is a relevant problem. Its solution is associated with both the study of the kinetics of processes in laser media and the development of new excitation systems. In this work, a system for exciting metal vapor active medium is suggested. It consists of three pumping sources, a synchronization system, and software. High voltage pulses are generated by three independent inverters; thyratrons are used as switches. The main capabilities of the system and the prospects for its use for implementing non-typical lasing modes are considered.

The technique of laser reference stars is an integral part of modern adaptive optical systems of ground-based telescopes. The requirements for the energy, spectral, and spatiotemporal characteristics of a laser beam for creating sodium laser guide star, as well as for the adaptive optical system as a whole, are largely related to the atmospheric parameters of telescope site. One aspect of optimizing the brightness of a sodium laser guide star is the choice of linewidth of the laser. In this work, based on numerical simulation of the interaction of laser radiation with mesospheric sodium atoms under the conditions of midlatitude atmosphere in the Russian Federation, the effect of laser bandwidth on the magnitude of the return photon flux from a sodium laser guide star is estimated to determine the requirements for the parameters of the laser. Results are presented for laser radiation with circular polarizations and linewidths from 10 MHz to 3.5 GHz.

The paper presents the results of studying the influence of the morphology and composition of thin films that form the structure of dielectric mirrors of optical resonators of coherent sources for LIDARs. The Optilayer software simulated dielectric mirrors based on two pairs of materials: TiO₂/SiO₂ and ZnS/YbF₃. Using electron and atomic force microscopy, their morphological features were determined. The calculated structure of the interference coating was deposited onto a substrate using the ion-beam sputtering method. The threshold of laser-induced breakdown of dielectric mirrors by Nd:YAG laser radiation at a wavelength of 1064 nm was found to be 4 J/cm² for a TiO₂/SiO₂ mirror and 4 J/cm² for a ZnS/YbF₃ mirror.

The work is devoted to modeling the disturbance propagation in viscous incompressible laminar boundary layers, using linearized equations for disturbance amplitudes. Along with the numerical model based on original linearized equations, the article considers three models based on equations derived from the original ones by neglecting the streamwise pressure gradient, or the streamwise viscous terms, or both. The models are compared numerically by the example of generation and propagation of disturbances in the boundary layer over a slightly concave plate. Conclusions are drawn about the feasibility of the same simplified models to adequately simulate both Tollmien-Schlichting waves and Görtler vortices in a range of practically important parameters.

The paper presents results of a theoretical study for parameters of a compressible boundary layer for the case of a re-entry space vehicle flying in atmosphere with the free flow at Mach 6≤M≤10 with sublimation of the carbon coating (graphite). Since a high flight velocity results in a higher wall temperature and a higher mass loss rate, the effect of wall material evaporation decreases the wall temperature as compared with the case of zero-sublimation flow. All that increases the gas mixture density in the sublimation vapor cloud nearby the wall; this is beneficial for stability of the high-speed boundary layer in the response to the first-mode disturbance. As for the second mode disturbances, the lower values of spatial amplification rate with increasing Mach number is observed due to the surface material sublimation. The position of laminar-turbulent transition was evaluated using the e^N method. Our computations demonstrated that (for a flow with M = 6) the surface sublimation has no influence for laminar-turbulent transition; this transition is governed by the growth of three-dimensional (3D) first mode disturbances. At higher Mach numbers (for M = 8 and higher) we observe that the disturbance amplification rate in the downstream direction becomes smaller. The transition is driven by a 2D second mode. The graphite coating sublimation has destabilizing influence for the second mode; that accelerates the boundary layer transition to turbulence.

Velocity fields and air flow structures have been experimentally established in a local working area with a horizontal panel heated by a gas infrared emitter in the modes of free and mixed (during operation of the air exchange system) convection using the optical SIV (Smoke Image Velocimetry) method. The analysis of the influence of the structure of the air flow, resulting from the heating of surfaces located in the local working area, on the formation of air velocity fields in the operating conditions of a gas infrared emitter was carried out. The extent of the influence of the convection regime on the aeromechanics of the local working area heated by a gas infrared emitter has been established.

A pioneering experimental study of the influence of distributed suction of a supersonic boundary layer on a flat plate on its stability to controlled (artificial) disturbances at the freestream Mach number М_∞ = 2 is performed. Experimental results are compared to numerical predictions, and good quantitative agreement is observed. The conclusions of the linear stability theory that suction of the type considered in the study stabilizes the flow in a supersonic boundary layer are experimentally validated; moreover, the stabilizing effect of suction is more pronounced than the destabilizing effect of surface porosity.

Tests of a streamlined cone with a rear hemispherical part were carried out in a supersonic wind tunnel using an installation of free oscillations along the pitch angle at Mach number M = 1.75 and for several values of the body inertia moment (calculated relative to the axis of rotation). In all tests, after the completion of the transient process, undamped oscillations of the cone were recorded with an amplitude depending on the reduced frequency. The dependence for the of undamped oscillation amplitude on the reduced frequency exhibits a pronounced resonant behavior.

The paper presents the results of the study of effective turbulent heat transfer along a rod bundle at its transverse streamlining, performed using the CONV-3D code based on the DNS approach. To determine the effective heat conductivity coefficient, the mixing of two plane-parallel coolant flows, moving at the same velocities and having different inlet temperatures in the working area was simulated. Comparison of the calculation results with experimental data for water has confirmed the usability of numerical modeling instead of real experiments. Such a replacement of a real experiment with its computational analogue is relevant for investigation of liquid metal coolants.

The action of a pair of weak shock waves on a supersonic boundary layer on a swept flat plate with a bluntness radius of the leading edge equal to 2.5 mm at the Mach number 2 is experimentally studied. Transverse hot-wire measurements are performed in the boundary layer with a fixed distance of the probe from the model surface. It is found that a change in the sweep angle of the leading edge from 35 to 45 degrees reduces the intensity of the action of the weak shock waves on the boundary layer flow. As the sweep angle of the leading edge increases to 50º, the weak shock waves no longer affect the flow in the supersonic boundary layer on the swept plate.

The paper presents the results for simulation of heat transfer between the laminar axisymmetric methane/air flame and a cold flat surface; simulation was performed for the distance between the burner exit and the flat surface equal to the one, two, and three exit calibers. The study is based on the direct numerical simulation with a detailed kinetic mechanism with the GRI-MECH 3.0 code. Simulation for the configuration with the distance of three calibers demonstrated a significant reduction in heat flux nearby the front point; this is due to a local recirculation zone between the flame cone and the flat surface. This phenomena can explain the experiment-observed reduction in heart transfer.

A modified method of transfer units is developed for a countercurrent film cooling tower with a structured tubular packing with surface intensifiers in order to determine the thermal efficiency of the gas and liquid phases and the temperature of the cooled water at the output. The approach of presenting the number of transfer units, taking into account additional terms with reverse mixing coefficients is applied to indirectly consider the hydrodynamic structure of flows and a decrease in the heat and mass transfer efficiency, compared with the ideal displacement model. An experimental installation with a layout (column) of a Plexiglass cooling tower with a diameter of 200 mm and a height of 2 m is described. Experimental data for water cooling in a structured packing block in the form of a vertical bundle of tightly packed polyethylene pipes with a diameter of 0.05 m with an annular discretely structured surface roughness are presented. Generalized calculated empirical expressions for the drag of dry and irrigated pipes, as well as the dependence of the volumetric mass transfer coefficient on air velocity at different irrigation densities, are obtained. The parameters of expression of the modified number of transfer units are identified based on experimental data on thermal efficiency in the gas phase. As a result, the dependence of the thermal efficiency in the gas phase on the pressure and design characteristics of the structured packing is obtained taking into account the reverse mixing of the flows. Reverse mixing is shown to reduce thermal efficiency by 8 - 15 %, which must be taken into account in the calculations of film cooling towers. The calculation results for the SK-400 industrial cooling tower using the presented expressions are provided and the agreement of the thermal efficiency of the cooling tower with the calculation according to the proposed method is shown.

The effect of capillary-porous coatings obtained by the method of directed plasma spraying on the dynamics of evaporation and heat transfer during nitrogen boiling under conditions of steady-state heat release on copper tubular heaters with a diameter of 16 mm was experimentally studied. It is shown that the presence of coatings leads to an increase in the critical heat flux relative to a smooth heater and heat transfer intensification by the factor of up to 3.5 in the region of low heat fluxes. According to the analysis of high-speed video filming, intensification of heat transfer at low heat fluxes is associated with a significant activation of stably operating nucleation sites. With a subsequent increase in the heat load, intensification relates to a significant contribution of high-intensity heat transfer in the macrolayer zone in local areas between the ridges of structured coatings. It is shown that there is a decrease in the slope of boiling curves of the modified heaters in the pre-crisis regimes, determined by the pulsating behavior of interfaces and accompanied by significant fluctuations in the surface temperature.

The article presents the results of pulse heating measurements for the thermal resistances of contacts of liquid lead with Al₂O₃ ceramics and steel in gaps, modeling a heat conducting liquid-metal sublayer in the developed fuel rods of fast reactors of a new generation. The method of obtaining and processing experimental data is described, the results of estimating the measurement error are presented, and the dependence of thermal resistances of liquid lead contacts in model gaps on temperature and number of melting and crystallization of lead is investigated. Based on the experimental results, the thermal resistance of a heat conducting liquid-metal sublayer in fuel rods is evaluated.

The experimental results on the structure of the two-phase “liquid metal-gas” medium in vertical channels depending on the gas flow rate and channel diameter are presented. Lead-bismuth melt at a temperature of 160°С was used as a liquid medium, and argon was used as a gas phase. Data were obtained on the shape of gas bubbles, temporary changes in the gas content in channels, histograms of gas content distribution, and features of the slug flow of gas in the metal melt.

The results of an analytical solution to the problem of heat distribution inside a massive solid sample with concentrated heat supply to this sample surface are presented. Analytical expressions for the non-stationary temperature distribution inside the body are obtained using the integral cosine Fourier transform and the Hankel transform. Examples of solution application for estimating the characteristic times of reaching the Chernov points Ac₁ and Ac₃ in model hypoeutectoid steels under the effect of laser radiation are presented. The application of this solution to calculating the cooling dynamics of ceramic Al₂O₃ and SiO₂ samples, affected by the air and water jets, is demonstrated.

The structure of a gas-liquid flow and interfacial mass transfer during the transition from the slug to the bubbly flow of ethanol-CO₂ mixture in a horizontal straight microchannel were experimentally studied. The experiments were performed for a channel with a rectangular cross section of 141×385 μm in the range of superficial gas and liquid velocities J_G = 0.16 - 0.8 m/s and J_L = 0.22 - 0.5 m/s. To determine a change in the volume of the elongated bubble along the microchannel length due to CO₂ absorption, the method of high-speed visualization with subsequent image processing was applied. The bubble frequency, velocity, size, and change in the volume of gas slugs and bubbles along the channel were measured, and volumetric coefficient of mass transfer from liquid k _L a was calculated. The measured volumetric mass transfer coefficient was compared with the known correlations and a new correlation was proposed for the transition from the slug to the bubbly flow due to interfacial mass transfer.

Numerical studies of aerodynamics and heat transfer in a vortex burner during flame oxygen combustion of pulverized coal are presented. The proposed numerical method has been tested using experimental data on oxygen combustion of coal in a flow. The influence of oxygen concentration in the blast on the processes of ignition and combustion of coal dust in a nitrogen-free environment has been considered. It has been established that for the burner under study, an increase in oxygen concentration from 40.1 to 66.7 vol. % leads to a change in the flow structure, an extension of the flame size, and an increase in the average value of unburned solid carbon concentration from 0.00136 to 0.4 g/m³ at a distance of 1.5 m from the burner.

The flow around a stationary gas Taylor bubble at downward flow velocities from 0.15 to 0.3 m/s in a vertical tube with a diameter of 20 mm was experimentally and numerically studied. Three-dimensional calculations were performed using the VOF (volume of fluid) method in the OpenFOAM package with application of the unsteady κ-ω SST turbulence model. Hydrodynamic characteristics of the flow were experimentally studied using the electrodiffusion method. The effect of flow velocity on the change in the shape of the gas Taylor bubble nose was shown. The calculated and experimental data were compared and their good agreement was shown. The distribution of velocities in liquid and gas was studied as well as the distribution of the liquid film thickness around a gas Taylor bubble. It is shown that the wall shear stress in the liquid film around a gas Taylor bubble does not depend on the downward flow velocity.

The results of thermodynamic calculations and experimental studies on hydrocarbon gas pyrolysis at atmospheric pressure in a combined plasma-chemical reactor with the production of hydrogen and carbon black with nano-carbon structures are presented. The plasma pyrolysis technology consists of heating hydrocarbon gas in an electric arc combined reactor to a temperature that ensures its dissociation into hydrogen and carbon black in a single techno-logical process.

Gas-driven atomization is the major approach for production of metal powders. This method gives up to 70 % of the entire metal powder production. However, modern trends demonstrate new requirements to the particle size distribution. This drives the development of novel methods for power production. Here we present the plasma-jet atomization method.

In the context of modern climate change, permafrost degradation from the surface takes place in Western Siberia. This is manifested by an increase in temperature and a decrease in the area of distribution and thickness of frozen layers. To establish the rate of reduction in permafrost area, a cartographic model was created to predict the change in the position of its southern limit by the middle of the 21st century. Based on temperature, ice content, rock composition, and section structure data, permafrost areas were ranked concerning the thawing rate of the upper 10-m-thick permafrost layer. It was found that the expected change in the southern limit of permafrost in Western Siberia will be uneven and dependent on the local conditions related to the cryolithogenic foundation of the landscape.