Home – Home – Jornals – Atmospheric and Oceanic Optics 2024 number 1

High-resolution spectra corresponding to the rotational and the ν₂-ν₂ bands of the two most abundant isotopic species of ozone with one heavy ¹⁸O oxygen atom were recorded using SOLEIL synchrotron radiation source in the range 30-200 cm^-1. Additionally, the ν₂ vibrational-rotational bands were recorded between 550 and 880 cm^-1 using a classical glowbar source that made it possible to extend and refine information compared to published data on the observed transitions of these bands. The analyses of recorded spectra permitted us to deduce experimental set of energy levels for the ground (000) and the first bending (010) vibrational states, which significantly exceeds literature data in terms of rotational quantum numbers. For both isotopic species, the weighted fits of all experimental line positions were carried out including previously published microwave data. As a result of this work, the improved values of rotational and centrifugal distortion parameters for the states (000) and (010) were obtained that permitted modelling the experimental line positions with a weighted standard deviation of 1.284 (2235 transitions) and 0.908 (4597 transitions), respectively, for ¹⁶O¹⁶O¹⁸O, and 1.168 (824 transitions) and 1.724 (2381 transitions) for ¹⁶O¹⁸O¹⁶O.

Room-temperature cavity ring-down spectra (CRDS) of hydrogen sulfide were recorded at three pressures of 10, 20, and 30 Torr in the 12950-13300 cm^-1 range with a sensitivity on the order of 3 × 10^-11 cm^-1 in terms of the absorption coefficient and analyzed. The line positions and intensities are derived from these spectra. The theoretical simulation of these spectra was performed within the method of effective operators. The measured line positions and intensities are compared with the variational calculated values. Considerable difference between calculated ( Azzam A.A.A., Yurchenko S.N., Tennyson J., Naumenko O.V. Exomol line lists XVI: A hot line list for H₂S // Mon. Not. R. Astron. Soc. 2016. V. 460. P. 4063-4074) and observed line positions and intensities is found.

The article presents and discusses the statement of the problem, goals and objectives, methodology, tools, software and research results obtained during the development of the prototype information and analytical system “Ecological Barometer”. A review of research in the area of knowledge under discussion has been completed. A system of characteristics for measuring the level of environmental safety is outlined. Sources of primary data are described in detail. The system involves the implementation of monitoring and analysis of key characteristics of the state of the environment based on data obtained using artificial intelligence technologies.

The article deals with the use of interactive seminar model for the development of professional competencies and activation of scientific activity of students in the discipline “Life Safety”. Traditional formats of seminars in higher education have their disadvantages. The interactive workshop model developed by the author, using the “Workshop” module in the Moodle learning management system, includes such elements as discussions, collective assessment, small group work, surveys, questionnaires and webinars. These activities promote critical thinking, collaboration, and active student participation. This model addresses the shortcomings of traditional seminars and improves the quality of research papers, deepens the understanding of compulsory disciplines and prepares students for scientific endeavors.

The features of the formation and implementation of the industrial and energy policies of the European Union, aimed at achieving the goals of ensuring the functioning of “green” energy in the context of strengthening anti-Russian sanctions and global climate change, are considered. Options for regional and global development in the medium and long term are substantiated, taking into account the dynamics of prices for energy products and structural changes in their production and consumption

The article presents an overview of the features of the economic development of the country during the period of liberal transformations and the problems associated with ensuring technological sovereignty in Russia. The main ones are: a low share of innovations in the structure of industrial production, as well as enterprises that carry them out; obsolescence of a significant part of fixed assets in industry; a high key rate of the Central Bank of the Russian Federation, which does not contribute to economic growth and acceleration of industrial modernization in Russia. The article attempts to identify the elements of macroeconomic policy that contribute to ensuring technological sovereignty. To achieve economic growth, it is necessary to significantly increase the share of investments in fixed and human capital. To activate investment activity in the real sector of the economy, it is necessary to reduce the discount rate. In order to overcome the technological gap and solve the problem of import substitution, it is also necessary to optimize the industry and antimonopoly policy. It is necessary to reconsider the attitude to the integration policy of enterprises in the markets in order to increase their production efficiency, despite the increase in the level of concentration, and also to determine which structure in key industries is optimal for solving the problem of import substitution and restoring production chains destroyed as a result of sanctions.

The work is devoted to the issues of interaction between the state and private sector organizations in the field of innovation. The article defines the place of the scientific and technological sphere in the general structure of the economy, substantiates the prerequisites for the circulation of technologies at various levels of the market. The features of the Russian system of protection of intellectual property are highlighted. An analysis of the state policy in the field of innovative development is given. A mechanism has been proposed to stimulate R&D and import substitution based on the provision of subsidies for the purchase of components within the framework of existing business processes.

The article presents the possibilities of applying the methods of applied statistics used in modern analysis to analyze the dynamics of the exchange rate. The exchange rate in the modern world is quite a significant tool of the economic system of the state. Determining the trend in the development of the exchange rate is important in almost any business direction that involves capital investment. In modern economic conditions, it has a rather differential character, which is accompanied by risk, to one degree or another. And although assets in US dollars have declined in recent years, the Central Bank did not plan to completely abandon the dollar in its reserves, since this currency is necessary to maintain financial stability, given the high role of the US currency in foreign trade settlements and its fundamental role in financial flows. To predict the dynamics of the exchange rate, the official US dollar exchange rate was taken. Methods of constructing predictive models using ARIMA models and prediction models based on neural networks are proposed for making forecasts. The models were evaluated and the most accurate variant was proposed - a model based on the construction of neural networks (MLP model 12-8-1 (No. 4)) with a prediction error of 6 %.

This publication completes the presentation of part of the results of a study conducted at the Research Institute of Information Technologies of Federal Penitentiary Service of Russia. The purpose of the study is to increase the effectiveness of departmental statistical surveillance in the field of organizing the work of the security service to ensure the security of institutions of the penal system. As a result of the study, it was decided to make significant changes to the composition and organization of statistical indicators, which are intended to inform the Department of Protection and Escort of the Federal Penitentiary Service about service dogs of institutions of the penal system. Problems in the field of breeding German Shepherds have aroused the interest of specialists in service dog breeding to dogs of other breeds that differ in the presence of universal abilities, in particular to Rottweilers and Belgian shepherds (Malinois). The article emphasizes the importance of collecting, processing and analyzing statistical information about the number of dogs of these breeds.

To objectively determine the role of assets in the business of commercial organizations, to measure their value, it is important to disclose their functional purpose and use the appropriate tools for its evaluation. Goal. The purpose of the study is to substantiate and develop tools for assessing the functional purpose of assets of commercial organizations. In the course of the research, the works of Russian and foreign authors were studied, classified into those who identify assets and financial resources (N.I. Berzon, I.A. Blank, G.S. Gabidenova, A. Damodaran, V.V. Kovalev, V.V. Korshunov, M.V. Livson, M.R. Matthews, M.H.B. Perera, M.A. Eskindarov) commercial organizations, and vice versa. Recognition of assets as an independent economic category necessitates the formation of tools for their assessment in commercial corporate organizations. Based on the analysis of debatable aspects, the functional purpose of assets of commercial organizations is determined, including: measurement of the value of the organization’s economic turnover; characteristics of accumulated potential; participation of assets in achieving sustainable capital formation; protection against the risk of loss of liquidity by highly liquid assets exceeding the min mark, guaranteeing the safety margin of equity; production; influence on the level of risky activity of the organization; direct participation in the assessment of its financial condition. As a result, a methodological toolkit for assessing their functional purpose has been developed, which provides for the distribution of the established ranges of values of financial indicators describing the functional role of assets by phases of the economic cycle (the participation of assets in achieving sustainable capital formation - the stability of sources of asset formation, financial tension, autonomy; production - indicators of turnover and profitability of assets; influence on the level of risk activity - capital multiplier, the share of the most risky and non-performing assets in their total aggregate, etc.) based on the professional judgment of specialists.

The article analyzes the topical issues of the implementation of digitalization in fiscal management, revealing the development of digital resources applied by Federal Tax Service that advances accountability in the sphere of taxation. The article reasonably states that it is still difficult to foresee all the risks of digital transformation but observing the priority of the digital principles it is possible to avoid these risks in the nearest future. This study substantiates the prospects of further development of digitalization in fiscal management.

This article is devoted to the contribution to the development of Russian accounting by one of the outstanding scientists of the XX century Alexander Pavlovich Rudanovsky. Particular attention is paid to balance sheet as a central category in the researcher’s works. In Rudanovsky’s works the balance sheet can be considered as a model in the modern sense of economic relations. Despite the fact that Rudanovsky’s ideas were not subsequently developed by Soviet economists, they were highly appreciated and inspired post-Soviet researchers to updated concepts. Thus, the study of its theoretical provisions remains relevant.

The paper analyzes the directions of using the budgetary funds of local governments, which made it possible to identify the main items of their expenditures. This study is aimed at identifying the main directions of local government spending for various types of municipalities, at determining the sufficiency of funds allocated for socially significant areas. The general situation in terms of the sufficiency of financial resources made it possible to characterize the results of calculations, both of the main areas of expenditure obligations, and of total expenditures at constant prices. An analysis of the structure of budget expenditures for different types of municipalities made it possible to identify the main expenditure components in local budgets of various types. The results of the performed analysis will be useful for determining the directions for improving the fiscal policy in order to achieve the required level of spending in the most important socially significant areas.

The movement of passengers and cargo along the Northern Sea Route requires the organization of support for navigation from many services on the continent. Ensuring the stability of the movement of passengers and cargo on high routes of the Northern Sea Route is a problem that needs a comprehensive solution. The article presents the author’s approach to the rational spatial organization of airfields in the aviation infrastructure of the Arctic zone of the Russian Federation necessary to achieve the goal and solve the problems of ensuring the stability of the movement of passengers and cargo on high routes of the Northern Sea Route. Both organizational and technical and economic requirements for the organization of support for the movement of passengers and cargo following the upper routes of the NSR with the use of Arctic-type helicopters are disclosed.

The relevance of paper is due that to the fact the power grid complex of the Russian Federation has a significant impact not only on the economy of the country, but also on the comfort level of citizens. The aim of the study: to analyse the problematic issues of power grid development in the Russian Federation and to propose possible solutions using the principles of «lean production». The basis of the study was formed by the works of authors: K.K. Sevostyanova, T.S. Ilyinskaya, Y.L. Alexandrov, E.V. Skubrii, Y.D. Alexandrov and others. As a result, it was concluded that part of the problems typical for the electric grid complex of the Russian Federation can be solved by creating a Unified Electronic Platform for suppliers and territorial grid organizations.

The paper presents the results of numerical simulations of high-velocity turbulent air flows in a plane channel with a variable cross section exhibiting sudden expansion with allowance for coupled heat transfer with copper plates modeling the sensitive elements of heat flux probes. The simulations are performed for conditions of a high-enthalpy short-duration wind tunnel whose specific features are the short duration of the test regime and unsteady “falling” conditions at the model channel entrance. The wave structure of the supersonic flow, which affects the heat fluxes at the walls, is analyzed for various Mach numbers at the model channel entrance. The numerical algorithm is validated on the basis of experimental data on heating of the sensitive elements of heat flux probes for unsteady input conditions at the channel entrance. The influence of the Mach number, static parameters, and stagnation parameters on the rate of heating of the sensitive elements located at various points in the channel is studied numerically. The heat fluxes calculated under constant and “falling” conditions at the channel entrance are compared. It is shown that the accuracy of heat flux modeling can be increased by taking into account the intensity of fluctuations of the flow parameters and their changes along the channel.

Fuel rod assemblies with dense packing are promising from the point of increasing the conversion rate and heat transfer in small modular reactors. The main feature of the flow in the dense packing is the formation of quasi-periodic large-scale velocity pulsations in a gap between fuel rods, which intensify mixing between the subchannels and greatly increase heat transfer between the fuel rods and the coolant. The large-scale pulsations relate directly to the pitch-to-diameter (P/D) ratio of the rod bundle and the Reynolds number (Re). In this work, the unsteady flow structure in a gap between a flat wall and three rods with a relative pitch P/D = 1.077 is experimentally studied using the PIV method with high time resolution. The averaged flow characteristics, including the three-dimensional ones, are presented. The influence of the Re number on flow oscillations in the gap was studied. The spatial most energy-intensive flow modes were analyzed using the POD method. The results obtained indicate the presence of several traveling waves propagating along the flow. Modulation of flow oscillations in the gap was detected. These investigation results are in good agreement with the results of other authors.

Turbulent flows in a flat diffuser are characterized by the presence of two local maxima in the profiles of longitudinal velocity pulsations. The mechanism of formation of a turbulent flow structure in a flat diffuser was experimentally studied. For this purpose, the parameters of the flow kinematic structure in a diffuser with an opening angle of 2.5° were measured. The profiles of velocities and turbulent characteristics of the flow in the typical cross-sections of the channel were obtained using the optical measurement method; based on these profiles the secondary flows in the diffuser were identified. A physical model of formation of the turbulent flow structure is proposed. Within the framework of this model, a high degree of turbulent pulsations far from the wall is associated with the convection of turbulence from the near-wall region into the flow core by a secondary flow in the form of an averaged spiral motion of the medium in a flat diffuser.

The paper presents the results of a numerical study of flow gas dynamics and integral parameters of the flow at the channel entrance located behind a conical or plane shock wave. The free-stream Mach number range is М = 2 - 4 and the range of the slopes of the compression surfaces of the wedge and cone is δ= 10 - 90°. Data on the flow structure at the channel entrance, mean-mass Mach numbers, total pressure loss, and flow rate coefficients are obtained. A comparative analysis of these parameters is performed, and advantages and drawbacks of the channel entrance positions in various types of the flow are noted.

The paper presents a method of molecular modeling of fluid transport coefficients, which is an alternative to the method of molecular dynamics. The transport coefficients are determined using fluctuation-dissipation theorems. The dynamics of molecules is calculated stochastically, with intermolecular forces being set using the appropriate created database. A distribution function of intermolecular forces is constructed and a formula is obtained for its analytical approximation. The method effectiveness is demonstrated by the example of calculating the viscosity and thermal conductivity coefficients of liquid argon and benzene. The obtained data are compared with the data of experimental and molecular dynamic modeling and their good agreement is established. With the same modeling accuracy, the developed method is shown to be significantly more time-efficient compared to the molecular dynamics method.

Supersonic gas-liquid jets of a coaxial atomizer at high liquid concentrations are studied experimentally. A complex of optical techniques is used for studying the droplet sizes: visualization and particle image velocimetry, laser Doppler anemometry, and Malvern Spraytec instrument. The research shows that the velocity and concentration profiles change with flow rate growth: an extended region with small droplet velocities appears behind the bow shock wave; in this case, the concentration decreases significantly slower than that at low liquid flow rates. A small increase in the jet energy at liquid flow rates greater than 100 l/h and a noticeable increase in the droplet size testify that the gas jet capabilities for breaking up the liquid in the described regimes are exhausted.

Rarefied gas flow into a vacuum through short linearly diverging and converging channels has been examined with the direct simulation Monte Carlo method. Solution to the problem has been suggested using complete geometric setup, with quite large areas on inlet and outlet of a model channel in examined geometry. A mass flow rate through the channel and flow field both inside the channel and upstream and downstream have been calculated in a wide range of gas rarefaction. These calculation results are comparable to corresponding data for the channel with constant cross section. A strong impact of channel geometry and gas rarefaction has been proved.

Experimental study was performed on dynamics of vapor bubble rising in the annular channel at subatmospheric pressure. The gas bubble is formed during boiling of an overheated degassed liquid in an annular channel restricted by two glass tubes with the diameters of 25 and 16 mm. It was demonstrated that the dynamics of vapor cavity while rising the vapor bubble in the annular channel demonstrates a qualitative difference from the dynamics for an ascending gas bubble. The behavior is similar to a Taylor vapor bubble behavior in a round tube with a small diameter. One of typical features of vapor cavity behavior in an annular channel is possibility of vapor cavity decay after bubble collapse during the pulsation flow mode.

The paper presents the results of experimental study for rising a cluster of monodisperse gas bubbles in viscous liquid with/without surfactant for the Reynolds number in the range Re = 0.01 ÷ 1. The influence of surfactant type on the dynamics the bubble cluster rise has been analyzed. The qualitative pattern of monodisperse bubbles cluster rise was defined as a function of initial volumetric concentration in the range С_V = 0,001 ÷ 0,04. New experimental data were obtained on velocity and drag coefficient for a compact cluster of monosize bubbles rising in a liquid with/without surfactant (both for contact and contactless type of bubble rising.

Reflections of hydraulic jumps on shallow water are studied. Theoretical criteria of the transition between the regular and Mach reflections are derived, and it is shown that there is a domain of wave incidence angles where both types of reflection are possible. Numerical simulations reveal a hysteresis of this transition, which is consistent with theoretical predictions. It is shown that the hysteresis can be obtained by smoothly varying both the angle of the wedge generating the hydraulic jump and the free-stream Froude number.

This work examines the transition from kinetic to diffusion combustion using optical diagnostic methods. Experimental data were obtained on the temperature fields, composition and velocity of gas near the leading edge of a hydrogen flame flowing from a 2×20 mm slit into the air. The distribution of the rate of combustion products formation, intensity of heat release and pressure was obtained using the method of balances in equations of energy, momentum and matter transfer. It is shown that during the transition to diffusion combustion, heat release along the flame length decreases more slowly than the rate of water formation.

The problem of hydrodynamic stability of a boundary layer with diffusion combustion is formulated in the Dan-Lin-Alekseev approximation and at constant Prandtl and Schmidt numbers; it is reduced to solving a system of the tenth-order ordinary differential equations with homogeneous boundary conditions. With Lewis numbers equal to unity, it may be lowered to the eighth order. In the inviscid approximation, the stability problem is reduced to the integration of a single second-order differential equation. Based on the obtained stability equations and calculations of stationary flow parameters, the stability of a supersonic boundary layer with diffusive combustion on a permeable plate with hydrogen supply through its pores is studied for the first time by direct numerical modeling. With the Mach number M = 2, the possibility of flame flow stabilization is established using calculations. It is shown that within the framework of the inviscid theory of stability, it is possible to obtain quite reliable data on the maximum degrees of the growth of disturbances.

The paper studies the quality of water spraying by a pneumatic injection system designed for water injection into the input system of a piston internal ignition engine. The system consists of a two-cylinder piston compressor with compression of water-air mixture phase in the compressor’s cavities. The piston compressor has connection to the atomizer through long channels. The droplet sizes were measured through automatic image processing by the Shadow Photography method. The velocity field of droplets was measured by the 2D-PIV method . Experimental results demonstrated that the injection system offers a high quality of spraying for the air/water mass ratio higher than 0.46. The value of Sauter mean diameter was less than 31.1 µm.

The research considers the microwave treatment of snow-and-ice mass with the stages of heating and melting. A nonlinear mathematical model for two-phase Stephan problem was developed for the case of laminar set of dielectrics. We offer approximate analytical solutions for taking into account the thermophysical and electrophysical properties of layers; this approach allows parametric analysis.

The papers analysis the flow patterns for air flow around cubic-shaped buildings. Experimental and simulation data were compared for the flow problems with different scales. Geometry parameters for the models can be varied from 0.025 to 6 m, meanwhile the range of Reynolds number for considered data is from 10⁴ to 10⁶. The study proves that the problem is scalable one: this creates a foundation for running the lab-scale wind tunnel experiments.

Using an ultrasonic interferometer in the temperature range from 293 to 393 K at pressures from 0.13 to 1.5-2.8 MPa, the speed of sound U was measured in helium-xenon gas mixtures with a helium content of 60.34, 71.72, and 85.32 at. %. The measurement errors of temperature, pressure and speed of sound were ±20 mK, ±4 kPa and ± (0.15-0.30) %, respectively. By approximating the experimental data for each composition, equations were obtained to describe changes in the speed of sound as a function of pressure and temperature over the entire measurement range. The existing reference and experimental data on the speed of sound in inert gases and He-Xe mixtures were analyzed. A method for calculating U of mixtures with a helium content above 71.7 at. % He to a temperature of 1500 K and a pressure of up to 7 MPa was developed.

Numerical simulation was applied to the processes of heat and moisture transfer and for ice-water phase transition in a season-thawed soil layer. Analysis was performed for consequences of natural wildfire on the soil temperature and the thawing depth as a function of water retention by soil for the condition of Siberian permafrost zone. Calculations demonstrate that the permafrost thawing depth increases due to burnout of the top organic horizon. The quantitative indexes of natural wildfire impact depend on water retention properties of the upper organic horizon of soil.

Using isothermal drop calorimeter, the enthalpy increment of the Na₁₅Pb₄ and Na₅₀Pb₅₀ alloys was measured and the heat capacity was determined in the temperature range of 420-1075 K, including the solid and liquid states. It has been established that the values of the heat capacity of melts significantly exceed the calculations of this value according to the laws for an ideal solution, and this difference decreases with increasing temperature. The obtained results confirm the currently known fact that various complexes with a partially ionic character of the interatomic interaction are formed in melts of alkali metals with lead systems.

The possibility of obtaining a composite material from a ferroalloy based on silicon, aluminum, and zirconium nitrides by the method of self-propagating high-temperature synthesis is considered. It is shown that introduction of a nitrogen-containing additive on the basis of ferroalumosilicozirconium in amounts up to 35% to the initial ferroalloy leads to an increase in the nitrogen fraction, emission of the basic nitride phases in combustion products, deceleration of motion of the combustion wave front, and reduction of the maximum combustion temperature. It is found that introduction of a preliminary nitridized material in amounts of more than 20% makes it possible to convert combustion wave front propagation to a steady regime and to obtain combustion products with a macroscopically homogeneous composition. Under the conditions of natural filtration of nitrogen, combustion of a powder mixture based on ferroalumosilicozirconium and a nitridized material yields a composite consisting of AlN, Si₃N₄, ZrN, and α-Fe phases.

A study of the process of mechanochemical synthesis of titanium nitride under conditions of double mechanical activation of titanium powder: in argon and in nitrogen gas is presented. In the experiments, the time of mechanical activation of titanium in argon and nitrogen was varied. Analysis of the morphology of powder mixtures, X-ray diffraction and microanalysis data showed that preliminary mechanical activation of titanium in argon helps to accelerate the mechanochemical synthesis of titanium nitride. Analytical relationships are obtained and theoretical estimates are given that make it possible to predict the process of double mechanical activation of titanium.

The formation of compounds of refractory metal foils (Ti, Hf, Ta, Ni) with ceramic layers formed as a result of combustion of reaction tapes rolled from powder mixtures (Ti + 0.65C, Ti + 1.7B and 5Ti + 3Si) was experimentally studied. The microstructure, elemental and phase compositions of multilayer composites obtained by self-propagating high-temperature synthesis were studied using scanning electron microscopy and X-ray diffraction analysis. The influence of synthesis conditions (initial temperature, applied pressure) and the initial structure of the samples on the speed of propagation of the combustion wave front, microstructure, phase composition and strength characteristics of the resulting layered materials was revealed. It has been shown that connections in the combustion mode between metal foils and reaction tapes rolled from powder mixtures are ensured due to reaction diffusion, mutual impregnation and chemical reactions occurring in the reaction tapes and on the surface of metal foils. The strength characteristics of the resulting materials (up to 275 MPa at 25 °C, up to 72 MPa at 1100 °C) were determined using a three-point loading scheme. The results are of interest for the development of structural materials operating under extreme conditions.

The effect of preliminary low-energy mechanical activation (MA) of nickel powder on the thermal explosion of the Ni₃Al intermetallic compound has been studied. Two synthesis methods are considered. In the first, the mixture was continuously heated by an external energy source. In the second, when the set temperature was reached, the external source was turned off. It has been shown that low-energy MA of nickel promotes the intensification of the synthesis of the Ni₃Al intermetallic compound. With continuous heating, the ignition temperature does not depend on the activation time and is equal to the melting point of aluminum. When heating with the external source turned off, preliminary activation of nickel reduces the solid-phase ignition temperature. It has been established that the activation of nickel in a laboratory mill allows one to avoid the factors of its passivation.

Boron is one of the most valuable fuels for rocket propellants. However, the boron oxide (B₂O₃) on the B surface has a high boiling point (1860 °C), which hinders the contact between the internal active B and the oxidation component during the ignition and combustion process. As a result, the ignition energy of B is higher and the combustion reaction rate is lower. In order to improve the ignition performance and reaction rate of B, a surface modification of B by means of surface purification by a solvent, surface grafting, and making a composite with aluminum (Al), which has a high combustion temperature, has been prepared. Composite particles of B purified by ethanol and thick flake Al (TF-Al), denoted by EB/TF-Al, have the fastest reaction rate higher by 96.6% than that of raw B and TF-Al composite particles (RB/TF-Al). Surface grafting of B with TF-Al composite particles (KHB-3/TF-Al) ensure the minimum ignition energy, which is 29.1% lower than that of raw B. As the ignition performance and reaction rate of B are improved by means of surface modification, the performance of B-based rocket propellants is expected to be improved.

The widespread use of flat electric heaters in technology and household appliances requires the search for simpler and cheaper technologies for their production. This work proposes a method for producing an electrically conductive coating (NiAl) and an electrically insulating layer (glass ceramics) in one stage - by the method of self-propagating high-temperature synthesis (SHS) in a thermally conjugated powder system (Ni + Al)/(PbO₂ + B + Al₂O₃ + glass). The process of propagation of the combustion wave front has been studied, the influence of layer thickness, the ratio of components in the powder mixture PbO₂ + B + Al₂O₃ + glass on the propagation speed and temperature of the wave front has been studied. combustion. An expansion of the wave front of the exothermic process was discovered when a mixture of PbO₂ + B was added to the lower layer. The addition of this mixture makes it possible to reduce the thickness of the NiAl layer and ensure the formation of a uniform dielectric coating. The phase composition and microstructure of the coating were studied. The optimal ratios of layer thicknesses and the composition of the powder mixture of layers have been established. The fundamental possibility of forming an electrically conductive and dielectric coating by the method of self-propagating high-temperature synthesis in one stage is shown.

Model expressions for the concentration diffusion coefficient and thermal diffusion factor of a binary mixture obeying the van der Waals equation of state are obtained. Model calculations at elevated pressure (density) require the equation of state parameters and thermal diffusion factor of the mixture in a low-density ideal gas state. The behavior of model relations is studied depending on pressure along isotherms. Near the critical state, the model diffusion coefficient has a minimum, and the thermal diffusion coefficient has a maximum. The diffusion and thermal diffusion models at elevated pressure are compared with experimental data for a number of mixtures. It is shown that they are in qualitative and generally quantitative agreement at different temperatures and concentrations of components. The van der Waals equation is not quite suitable for describing the experiment on compressibility and phase equilibrium at high pressure. This requires more complex and flexible modifications of the equation. Generalized expressions for model characteristics of the diffusion of the binary mixture in the case of such equations of state are given.