bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of the decision support system for ecological safety of Arctic communications
Authors: Bystrov V V , Khaliullina D N
Published: September 2020

The article is devoted to the development of software tools for information and analytical support of management in the field of ecological safety. In the work the attention is paid to the development of decision support system for the tasks of ecological safety on the example of Arctic communications. The authors propose the architecture of such a system, built in the form of a multi-agent software environment. The theoretic basis of the proposed architecture is the use of a combination of different approaches, in particular, functional-target, process, project and network-centric. The proposed architecture is divided into 4 main components (functional subsystems): system of ecological safety monitoring and assessment, distributed storage of data and knowledge, distributed decision-making system, distributed simulation system. The features of the implementation of individual components of the developed decision- support system for the ecological safety of Arctic marine communications are presented.
Pulse voltage stabilizer controlled by a microcontroller
Authors: Titovskii S N , Titovskaya T S , Titovskaya N V
Published: September 2020

The article describes the digital control contour of a pulse voltage stabilizer using one of the varieties of the integral - differential control law. The hardware-software implementation of such a control contour on the ATxmega 128A1 is considered using the analog-to-digital converter and event channels built into this microcontroller. The results of experimental studies of a pulse voltage stabilizer controlled by the specified microcontroller are presented. It is shown that this solution is applicable for the construction of power supplies for equipment of widespread use.
Algomonitoring of chernozem leached in agrocenoses of the forest-steppe of the Krasnoyarsk Territory
Authors: Fomina N V
Published: September 2020

The results of monitoring the number and structure of soil algoflora of chernozem leached in crops of forest-steppe zone of Siberia are presented. The taxonomic and ecological structure of the algoflora of the chernozem of the leached forest-steppe zone of the Krasnoyarsk Territory has been established. The presence of certain types of cyanobacteria and algae in the soil is a sign of soil fertility, and their accumulation of organic substances leads to the productivity of agrocenoses. A study of the reactions of soil algocenosis to chemical pollution of agroecosystems allows us to establish the level of their adaptation to the action of stress aggressive factors. The ecological structure of the algoflora of leached chernozem is represented by edaphophilic species, which form the basis of generic diversity. In the chernozem selected under barley, cyanobacteria dominated, capable of forming mucous covers resistant to the effects of toxins. In alfalfa crops, the most intense microscopic sprawls of soil algae were noted.
Use electrodes with high active electrical resistance as a way to increase the productivity of an ozone generator based on dielectric barrier discharge
Authors: Andreev V V , Kravchenko G A , Matyunin A N , Pichugin Yu P
Published: September 2020

The study is focused on the synthesis of ozone in discharge cells of dielectric barrier discharge (DBD), in which electrodes with high active electrical resistance are used. It is shown that such ozone generators have higher productivity in comparison with traditional devices in which metal electrodes with low active electrical resistance are used. The physical laws leading to such result were analyzed. Also, the paper presents the results of comparative experimental studies of the basic performance of ozone generators with high and low active electrical resistances of electrodes.
About functioning of radioelectronic equipment in the Arctic and Far North climatic conditions
Authors: Budyakov P S , Gawlicky A I , Cherckesova L V , Pakhomov I V
Published: September 2020

In a paper showed the information obtained during the tests about the mutual influence and interaction of internal and external climatic and electromagnetic intensive influences in the tested object. This information will help to detect hidden and vulnerable places in the devices, which will increase the noise immunity of the radioelectronic devices as a whole.
Reflection of acoustic waves from a bubble screen in water with hydrate bubbles
Authors: Gimaltdinov I K , Khusainov I G , Khusainova G Y , Gimaltdinova A A
Published: September 2020

Dynamics of acoustic signal passing through a bubble screen is investigated. The case when the gas inside the methane bubbles is in hydrate formation conditions is considered. Influence of the hydrate formation process, the initial radius of bubbles and the gas content on the value of the attenuation coefficient and the phase velocity of wave propagating through the deep-sea bubble screen have been studied. Coefficients of reflection and passage of sound waves are obtained at boundaries separating areas of single-phase and two-phase zones. It has been found that the hydrate formation process increases the wave attenuation coefficient by more than two orders of magnitude in the low frequency area (less than 1 kHz).
Application of polyurethane, rubber and aluminum as materials for the production of the dome separator
Authors: Chiglintseva A S , Nasyrov A A , Chiglintsev I A
Published: September 2020

The paper describes the use of the installation of the dome-separator, which is a huge tank, cylindrical in shape and open from the bottom. The installation height reaches several tens of meters and a radius of several meters. Such a design can be made of elastic (such as polyurethane, rubber) or hard (duralumin) materials. The dome-separator can be used to eliminate the breakthroughs of gas and oil wells at great depths (more than 500 meters), when blocking the well is a difficult event. Sufficiently large dimensions of the installation are needed so that the mixture entering it can be separated into gas and oil phases for selective selection. Also, the dome-separator can be used as a method of extraction. The manufacture of such a structure from elastic materials contributes to an easier way to transport the dome-separator to the place of operation. The mathematical modeling of such an installation showed that the manufacture of a rubber dome-separator contributes to more efficient heat storage inside the structure, which has a beneficial effect on the decomposition of hydrate, which can be formed under operating conditions.
On the issue of initiation of bubble detonation by small-amplitude waves
Authors: Gimaltdinov I K , Gizzatullina A A , Gimaltdinova A A
Published: September 2020

The features of detonation initiation in the bubble liquid with explosive gas waves of moderate amplitude and under the action of two waves that affect the bubble Wednesday. It is shown that the heterogeneity of the volume content and pre-decompression of the bubble medium can lead to a significant decrease in the amplitude of the initial wave that can initiate detonation. In addition, it is shown that by acting on a bubble medium across the boundary in two waves can be initiated the detonation is not near the boundary through which the disturbance is introduced, but in the “depth” of the bubble medium.
Mathematical modelling of pump station
Authors: Semenova K D , Savosteenko N V , Maksimov N.M , Belov N.A
Published: September 2020

This article discusses methods of regulating the water supply at the pump station of the first rise. The description of pump unit is drawn. Equipment characteristics of engine parameters and daily fluid intake of station are given. Modernization reasons are described. Functional diagrams of the three control methods and their brief descriptions are given, as well as the calculations of these methods. The optimal method for regulating the feed was selected, based on the studies. Mathematical model is given for chosen regulation method. Obtained resulted of mathematical modeling are presented on the graphs.
Analysis of anthropogenic contamination of soils by petroleum products
Authors: Zhichkina L N , Nosov V V , Zhichkin K A , Bespamjatnova L P , Grunina O A , Grunina A A
Published: September 2020

Contamination of soil by petroleum products is a major environmental issue in the subjects of the Russian Federation that occurs from human activities. The most recent example of such contamination is the oil spill in the north of the Krasnoyarsk region. The purpose of the research is to identify environmental impacts of anthropogenic contamination of soils in the Samara region by petroleum products. The paper provides an assessment of contamination of soils by petroleum products and an analysis of petroleum products content in background areas and long-term observation plots, which is the result of an impact contamination of soils. From 2014 to 2018, eight sources of impact pollution were surveyed. Of these, two – Chapaevsk (2014) and Novokuybyshevsk (2015) – resulted in moderately hazardous contamination of soils, one – Podbelsk (2017) – in moderate contamination of soils, three – Granniy (2015), Syzran and Tolyatti (2018) – in contamination exceeding increased background levels. Pollution of soils of long-term observation plots occurred only in 2014 (20 times above the background level). Analysis of soil samples taken from background areas revealed that the content of petroleum products in soil was 1.1-3.0 times above the background level. During the study period, the petroleum products content in soil changed from 7 to 1488 mg/kg. The area of remediated lands ranged from 1524.2 ha in 2015 to 735 ha in 2018. The total area value was 5650.9 ha.
Optimization of flywheel for starter-generator based on the differential electric drive
Authors: Maksimov N M , Savosteenko N V , Semenova K D , Belov N A
Published: September 2020

The article discusses a variant of the implementation of a starter-generator based on a differential planetary gear, in which a flywheel is integrated. The method of its control and the algorithm of operation as a starter-generator are described. The main task in this article is to develop a flywheel and optimize its weight and size parameters, taking into account the requirements for the design of starting equipment for the MTZ-80 tractor. The technical parameters of the D-240 diesel engine and the viscosity-temperature characteristic of the M-8Gz engine oil are given. The calculation of the kinetic energy that must be accumulated in the flywheel to start an internal combustion engine in severe climatic conditions is carried out. The weight and size parameters of the flywheel have been calculated. A mathematical model of a starter with a flywheel is built for showing the processes of starting an internal combustion engine in various conditions and allowing to assess the adequacy of mathematical calculations and conduct a comparative analysis.
Geodetic support for the landscape environmental studies
Authors: Oznamets V V
Published: September 2020

This study purpose is to study the geodetic support mechanisms in the ecological landscape studies. Research area - landscape ecology. The article explores the landscape elements that are used in ecological modelling. The relationship between landscape models and surveying work in this area is investigated. A significant difference in the environmental research geodetic provision and conventional geodetic works was revealed. It is shown that in environmental studies, geodetic support includes a territory structural analysis. Unlike ordinary geodetic works, which are normative, geodetic support for environmental studies is subsidiary. The difference is noted in some terms interpretation by ecologists and geodesists. This imposes additional requirements on the geodesist. The practical work results are presented.
Mathematical modeling of the temperature regime in a ventilated pile of sugar beet
Authors: Zavrazhnov A I , Zuglenok N V , Zavrazhnov A A , Tolstoshein S S , Koltsov S M
Published: September 2020

Significant losses of beet mass and sucrose occur while storing sugar beets in field piles that lead to an increase in sugar cost supplement. To reduce losses, it is necessary to store raw materials in ventilated piles. Temperature is a key factor in reducing losses. In matters of improving the active ventilation system of sugar beet its work management remains an urgent task. The results of the studies carried out are aimed at studying the temperature regime inside the pile, they made it possible to justify the layout of temperature sensors inside the storage for controlling the active ventilation system.
To the question of modeling processes in oil-producing a well during short periodic operation by electric centrifugal pump installations
Authors: Topolnikov A S , Gimaltdinov I K , Gimaltdinova A A , Kochanova E Y
Published: September 2020

In this paper, the modeling and optimization of the periodic operation of electric submersible pumps is investigated in accordance with the basic principles of modeling this process. The area of application of quasi-stationary and non-stationary models in the field of ultrashort periods of pumping and accumulation is estimated. The analysis of the influence of the frequency of the supply voltage supplied to the submersible motor on the energy efficiency of the electric centrifugal pump during periodic operation is carried out. Practical recommendations are given on modeling and optimization of the periodic well operation mode with the installation of an electric centrifugal pump.
Investigation of the influence of medium and microwave radiation parameters on the dynamics of decomposition of gas hydrate
Authors: Davletshina M R , Stolpovsky M V , Chiglintseva A S , Gimaltdinov I K
Published: September 2020

The paper considers the problem of dissociation of methane gas hydrate saturating a porous medium of finite extent under the action of an external radiation source. The mathematical model includes the equations of continuity, heat inflow, and Darcy’s law, and is supplemented by the conditions of mass and heat balance on the discontinuity surface. In this case, we consider the case when the left boundary of a porous system is impervious to gas and heat flows, and the power of the source depends inversely on the coordinate of the phase transition front. Based on a computational algorithm developed using the method of catching the front in the grid node, the influence of the initial parameters of the reservoir on the maximum temperatures and pressures implemented in the system is studied. The influence of the power of the radiation source and the volume content of gas hydrate in the system on the intensity of its decomposition is also considered.
Technologies for methane production from hydrogen using a heated liquid
Authors: Davletshina M R , Stolpovsky M V , Chiglintseva A S
Published: September 2020

The paper presents a mathematical model of dissociation of methane hydrate under thermal influence on a porous layer. The problem of influence of a heat source (hot liquid) on a porous layer of finite length initially saturated with methane hydrate is considered. Temperature distributions in the system at different times are constructed. The influence of the heat source temperature on the character of the phase transition boundary motion is investigated. A technological scheme is proposed, and on its basis a mathematical model is constructed that describes heating and simultaneous gas extraction into a combined well consisting of two coaxial pipes. The efficiency of the proposed method of gas production is analyzed.
Features of decomposition of gas hydrate when exposed to microwave radiation
Authors: Davletshina M R , Stolpovsky M V , Chiglintseva A S , Gimaltdinov I K
Published: September 2020

The article summarizes the results of numerical monitoring of the decomposition of gas hydrates in a high frequency electromagnetic field. The results of the numerical experience of the decay process are summarized. In addition, the distribution of temperature and pressure is presented, but in addition, the relationship with the coefficient of permeability. In this article, the features of decomposition of methane hydrate under the influence of microwave radiation are studied. It is shown that the values of temperature and pressure in the reservoir decrease with time and distance from the source of microwave radiation. The dependence of the expansion front coordinate on time for different values of the permeability coefficient is presented.
State-resolved and two-temperature rate coefficients for CO+CO=CO2+C reaction
Authors: Kustova E , Savelev A
Published: September 2020

Several state-resolved and two-temperature models for the rate coefficients of reaction CO+CO=CO2+C are assessed, and a new simple state dependent model is proposed. Various models for the two-temperature non-equilibrium factor are considered: the theoretical alpha-model and the models based on averaging the state-resolved rate coefficients over the Boltzmann distribution. It is shown that for the Starik model, taking into account vibrational excitation of the partner CO molecule as well as the reaction product does not affect the two-temperature reaction rate coefficients. If the vibrational excitation of only one CO molecule is taken into account, the Starik model and that proposed in this work with the parameter U = ∞ yield identical results. However, our model is more general since it is capable to account for the preferential reaction mechanism from high vibrational states. Two-temperature rate coefficients provided by the a-model agree well with the averaged state-to-state ones, but the parameter α cannot be fixed in the entire temperature range and has to be chosen according to the specific ratio T/Tv. Thus, our computationally efficient state-specific model is recommended for state-to-state flow simulations; when being averaged with different non-equilibrium vibrational distributions, it can be used for modeling two-temperature flows.
Effect of coaxially mounted disks on oscillations of a cylinder of large aspect ratio in air flow
Authors: Kaufman D V , Ryabinin A N
Published: September 2020

The damped rotational oscillations of a cylinder whose length-to-diameter ratio is nine are considered. In the head part of the cylinder, a disc is mounted coaxially on the leg. The effect of the disk on damping of oscillations is described by aerodynamic rotational derivatives. Wind tunnel experiment is performed with the flow past a cylinder fixed on an elastic spring suspension. The diameter of the coaxial disk and the distance between the disk and the end of the cylinder vary. Deflected from the equilibrium position, the cylinder performs damping oscillations. The dependence of the amplitude of rotational vibrations on time is determined by the tensometric method. Coefficients of rotational pitch derivatives are found.
Development of power processing unit for a low-power ablative pulsed plasma thruster
Authors: Bogatyi A V , Bogatyi V I , Gordeev S V
Published: September 2020

Research Institute of Applied Mechanics and Electrodynamics of the Moscow Aviation Institute (RIAME MAI) develops ablative pulsed plasma thrusters with low power consumption for small spacecraft. The paper considers the development of power processing unit (PPU) for such thrusters. PPU under discussion should meet the following requirements: design simplicity, small overall dimensions, ensuring the required power and frequency of thruster operation and high energy efficiency.
On stability of planar periodic motions of a satellite in vicinity of resonant rotation
Authors: Churkina T
Published: September 2020

The stability of planar resonant periodic rotations of a rigid body around its centre of mass in a central Newtonian field of forces is considered. The orbit of the centre of mass of the satellite is assumed to be an elliptical one, the body’s inertia ellipsoid is general. Resonant rotations examined mean that the body makes 3 turns around its centre of mass during 2 revolutions of the centre of mass on its orbit (Mercury-type resonance 3:2). For the set of eccentricity value e ε [0,0.25] typical for planets’ ones the regions of stability in the first approximation and regions of unstability are built in three-dimensional space of parameters (eccentricity and two inertial parameters).
The implicit fully coupled numerical method for flows in thermochemical nonequilibrium
Authors: Molchanov A M , Siluyanova M V , Kochetkov Yu M
Published: September 2020

A new effective implicit fully coupled numerical method to compute a high-speed flowfield that is in thermochemical nonequilibrium has been developed. Such a flowfield is described by coupled partial differential equations for the conservation of mass, momentum, total energy, vibrational energies, rotational energy, mass conservation for each species, etc. The total number of equations can be very large, which greatly complicates the solution of general finite volume vector equation when using the standard fully implicit approach. The proposed method allows us to reduce operations with block tridiagonal matrices to inversion of 4x4 matrices and trivial matrix multiplication operations. Moreover, the approximation factorization error is minimized. The numerical procedures were applied to solve chemical and thermal nonequilibrium flow past a sphere body at Mach 27 and chemically nonequilibrium heterogeneous flow in the channel of a combined ramjet with a solid fuel gas generator. The results indicate that new method is 4-5 times more efficient than the standard fully implicit method.
Numerical modelling of the reflected waves from gas cavities and methane bombs in the heterogeneous media of the Northern regions
Authors: Stognii P , Petrov I , Khokhlov N
Published: September 2020

The Arctic region contains lots of underground gas layers closed from the outside. In case of their opening, the gas is of great danger for the surface buildings and drilling equipment. In this work, we observe the main dangerous gas reservoirs – gas cavities and methane bombs. We build the mathematical models of these heterogeneities and presented the main mathematical equations allowing calculating the seismic waves spread through them correctly. The grid-characteristic method of the third order of accuracy is used in all the computations. We demonstrate the results of modelling the seismic waves spread through the heterogeneous medium with the gas cavities and through the homogeneous medium with the methane bomb. The analysis of the differences between the models is carried out. The problems of computing the models with gas cavities and with methane bombs need different approaches for the correct calculations, though the problem formulations are similar.
On the inherent polycrystal stress concentration under external loading on example of single-phase α-Fe samples
Authors: Gulin V V , Nikitin A D
Published: September 2020

It is known that most structural materials are polycrystals. Under any loading, the structural features of the polycrystal may lead to the appearance and accumulation of microplastic deformation due to stress concentrations. This statement is part of a multiscale approach to describing the fracture process. The present development of computer engineering allows modeling of complex non-homogeneous objects, such as polycrystal. In this paper, a numerical model is developed for analyzing of the polycrystal stress state under mechanical loading. It is shown that inherent stress concentration takes place. The localization and statistical estimation of inherent stress concentration is made on the example of α-Fe polycrystal.
Verification of numerical model of temperature calculations in radio-frequency ion thrusters
Authors: Abgaryan V , Balashov V , Kupreeva A , Nigmatzyanov V
Published: September 2020

A numerical model for temperature calculation in radio-frequency ion thrusters (RIT) is proposed. The equations used for heat fluxes determination differ from those used in the known computational models. A new way of distribution of a radiant power flux caused by the excited atoms and ions of the plasma discharge is proposed. In addition, a new radiant flux caused by recombination of ions and electrons on the surfaces bordering the discharge was taken into consideration. The numerical model was verified based on temperature measurements made with the thruster with an ion beam diameter of 8 cm operating at three different power modes. The temperature measurements were made by thermographic camera focused on blackened areas of the accelerating grid surface.
Stability Study of a Relative Equilibrium in the Planar Circular Restricted Four-Body Problem
Authors: Bardin B S , Volkov E V
Published: September 2020

We deal with the restricted planar four-body problem. That is, we consider motion of an infinitesimal small body (particle) under the Newtonian gravitational attraction of three bodies (primaries). It is supposed that primaries move in circular orbits forming Lagrange equilateral triangle; two of them have equal masses. By using the method of normal forms, we perform nonlinear stability study of a central configuration such that the particle is located in perpendicular bisector of the Lagrange equilateral triangle.
Study of methods of supplying a solid phase to a heterogeneous flow at high-pressures of a carrier gas
Authors: Borisov S A , Glukhovskaya Ju I , Dobrovolskiy S V , Platonov I M , Podporin I V
Published: September 2020

The study of the methods of supplying powder material to a supersonic heterogeneous high-pressure flow is carried out in order to determine the optimal type of dispenser that ensures the continuity of the supply of the solid phase to form a coating with anticorrosive properties on metal structures made of the following metal powders: stainless steel, aluminium and zinc or their mixtures using the low-temperature gasodynamic method. Various options for organizing the supply of powder to the main highway were also considered.
Modification of Gaussian elimination: technique, high resolution seismic model for area of natural accumulation of gases
Authors: Smaglichenko T A , Smaglichenko A V , Sokolova N V , Sayankina M K
Published: September 2020

The modification of Gaussian elimination is described here as numerical method to determine the physically adequate solution of the linear equations system that is affected by complexity of the data error (measurements, parameterization et. al.). Other modifications and algorithms are mainly established to efficiently overcome calculating issues. In order to avoid influence of errors in the data the proposed technique selects a set of invertible sub-matrixes. Developing the Tikhonov regularization theory the regularized subsequence is determined for each unknown under consideration. Application of the method to local seismicity data derived high resolution areas and revealed that the hydrothermal field of high concentration CH4 and CO2 is surrounded by rock having high seismic velocity. Based on this result we conclude that nature protects the gas flow due to special structure, which is likely presented by dense basalt. Decrypt of satellite images shows that the zone of lowest elevation does not intersect this structure. Particularities of background seismicity are examined for the gas area being studied. Factors learned from nature experience permit us to formulate conditions to select a place for underground gas storage.
On resonant periodic motions close to conical precession of a dynamically symmetric satellite in a weakly elliptic orbit
Authors: Bardin B S , Antipov A A
Published: September 2020

The motion of a dynamically symmetric rigid body (satellite) about its centre of mass in an elliptical orbit is considered. It is assumed that the eccentricity of the orbit is small and an external resonance caused by gravitational torque takes place. Periodic motions emanating from conical precession of the satellite are studied. Such periodic motions can be constructed in a form of convergent series of fractional powers of the eccentricity. The first terms of these series expansion have been calculated in an explicit form. The bifurcation phenomenon of the above periodic motions is investigated.
Multi-agent modelling of conflicts with uncertainty
Authors: Karandeev A , Osipov V , Baluta V
Published: September 2020

In the framework of the paradigm of the multi-agent modelling system, the features of the adaptive behaviour of agents under conditions of competition with increased uncertainty are often considered. Uncertainty is the result of increased dynamics in environmental conditions. Often these changes are the result of the actions of agents, but there are situations when the conditions change on their own. As a consequence, it would be a reasonable solution to investigate not the entire system at a certain point in time, but the dynamics of the behaviour of objects and participants in the phase space of the conflict state. This allows us to reduce the study of agent adaptation processes in a conflict environment to the analysis of the trajectories of achieving the goal in the state space. Given that the main parameters of the trajectory are the coordinates of the agent in the multidimensional state space at the time of the situation assessment, the degree of adaptation to the situation is characterized by the proximity of the current state to the optimal path leading to the achievement of the goal. The rationality of the ways to achieve the target state is evaluated according to the criteria of admissibility of resource costs and the degree of proximity to achieve the goal.
Longitudinal-transverse (“breathing”) vibration modes of orthotropic plates with and without account of its interaction with the surrounding acoustic media
Authors: Paimushin V N , Gazizullin R K
Published: September 2020

Based on the previously obtained improved equations of motion, the problem of free cylindrical vibration of a hingedly supported plate surrounded by acoustic media is considered. Plate motion equations are obtained taking into account the internal friction of the plate material according to the Kelvin – Voigt model. The motion of acoustic media is described by two-dimensional generalized Helmholtz wave equations, compiled taking into account the internal dissipation of energy by introducing into consideration the complex sound velocity according to Skudrzyk. Based on the obtained solution, a study of resonant nonclassical shearless longitudinal-transverse (“breathing”) forms of free vibrations has been carried out at various values of the physical-mechanical properties of the plate material and the parameter characterizing energy dissipation in the acoustic media surrounding the plate.
Through calculation method of fatigue damage
Authors: Nikitin I S , Burago N G , Nikitin A D , Stratula B A
Published: September 2020

A kinetic model of damage development under cyclic loading is proposed to describe the process of fatigue failure. To determine the coefficients of the kinetic equation of damage, the well-known criterion of multiaxial fatigue failure is used. A numerical method for calculating crack-like zones up to macro fracture is proposed. The results of fatigue experiments for various geometries and asymmetry coefficients were reproduced; the operability of the model and calculation algorithm were verified.
Simulation of seismic responses from the 3D non-linear model of the Bazhenov formation
Authors: Nikitin I S , Golubev V I , Ekimenko A V , Anosova M B
Published: September 2020

The article is devoted to the investigation of seismic responses from probable oil-bearing formations. The three-dimensional geological model of the Bazhenov formation situated at Western Siberia is constructed. It is based on the elastic two-dimensional cross-section with curvilinear boundaries between different layers. For this purpose, logging and seismic data were processed jointly. To describe correctly the internal structure of mudstones the novel continuum model of media with interlayer slippage and delamination was utilized. The grid-characteristic method was used to solve numerically the govern system of the linear elasticity. The non-linearity of the model is incorporated with the appropriate explicit-implicit approximation procedure. For increasing the reliability of obtained synthetic seismograms the presence of the static rock pressure was taken into account. Reasonable computational time was achieved with the help of the parallelization based on the Message Passing Interface (MPI) technology. To analyze the structure of seismic responses wave patterns for the model with different parameters were presented. The influence of fractured layer on registered seismic traces were estimated. The proposed numerical approach may be used for simulation of complex geological objects.
On orbital stability of resonant periodic motions originating from hyperboloidal precession of a dynamically symmetric satellite
Authors: Sukhov E A
Published: September 2020

Periodic motions arising from Hyperboloidal precession of a dynamically symmetric rigid-body satellite on a circular orbit are studied in this work. There exist two types of these motions categorized by frequencies ^ and co2
of the linearized system: short-periodic motions with period close to 2n/co2
and long-periodic ones with period close to 2?!/^ (co2 > co). These motions describe oscillations of the satellite’s principal axis in the neighbourhood Hyperboloidal precession and can be obtained as small-parameter power series of the oscillation amplitude. It has been shown before that in a resonant case there exist more than one family of long-periodic motions. In this work, families of long-periodic motions originating from Hyperboloidal precession in case of fourth order resonance are computed and analysed.
Nonlinear flutter response of cylindrical shell in thermal field and supersonic gas flow
Authors: Baghdasaryan G Y , Mikilyan M A , Vardanyan I A , Panteleev A V , Severina N S
Published: September 2020

The work is devoted to the investigation of flutter oscillations and stability of closed cylindrical shell in supersonic gas flow and placed in an inhomogeneous temperature field. It is assumed that supersonic gas flows on the outside of the shell with an unperturbed velocity U, directed parallel to the cylinder generatrix. Under the action of an inhomogeneous temperature field, the shell bulges out; this deformed state is accepted as unperturbed, and the stability of this state is studied. The main nonlinear equations and relations describing the behavior of the examined system are derived. The formulated boundary value problem is solved using Galerkin method. The joint influence of the flow and the temperature field on the relation between the amplitude and frequency of nonlinear oscillations of a cylindrical shell is studied. The critical velocity values are calculated from the corresponding linear system and are given in tables. The numerical results show that: a) the surrounding flow significantly affects the nature of the investigated relation; b) it is impossible to excite steady-state flutter oscillations (the silence zone) up to a certain value of the oscillations frequency; c) the dependence of the amplitude on the oscillations frequency can be either multi-valued or single-valued.
Benchmark analysis of novel multi-agent optimization algorithm using linear regulators for agents motion control
Authors: Karane M , Panteleev A
Published: September 2020

The aim of this paper is to develop algorithm and software for a novel multi-agent constrained global optimization method. In multi-agent algorithms, the solution search area is populated with agents. Some transformations occur over them, which lead to a global extremum. It was proposed to take as a basis the use of linear regulators to control the movement of agents group. At each stage of the algorithm, a search is made by closed loop agents control with various types of criteria. Using criteria of various types, a more detailed study of the solution search area and finding a global extremum is provided. This is the main feature and novelty of the algorithm under consideration. The method efficiency is studied on a standard set of test functions of two variables with a complex structure of level lines using the software developed. Efficiency analysis is carried out for Schweffel function and multifunction from the benchmark set. During the study, statistical characteristics were calculated, according to which the most suitable parameters were selected. The results obtained indicate that the algorithm successfully copes with such problems and can be used, for example, for problems in the theory of optimal control of dynamic systems.
Application of bio-inspired methods for optimal open loop discrete time deterministic control problems
Authors: Panteleev A V , Stanovskaya Y V
Published: September 2020

The article proposed the novel Sparrow colony optimization (SCO) algorithm to solve the optimal open loop control problem for nonlinear discrete deterministic dynamic systems described by difference equations. Numerical algorithm and software in Python programming language are implemented. Model examples demonstrating the effectiveness of the developed software are solved. Comparison of the considered algorithm results with a Dragonfly optimization algorithm at the solution of model problems is made. The recommended parameters values of the proposed algorithm are suggested.
The mini-batch adaptive method of random search (MAMRS) for parameters optimization in the tracking control problem
Authors: Panteleev A V , Lobanov A V
Published: September 2020

The tracking control problem for nonlinear dynamic system linear in control and signal tracked is considered. It is proposed to formalize the tracking problem as a problem of controlling a bunch of trajectories emanating from a given set of possible initial states. The quality of a single trajectory control is described by the value of the integral criterion, which depends on the square of the tracking error and the intensity of the control used. The control is sought from the condition of the minimum value of the average criterion defined on the set of the bunch trajectories. When choosing a control structure, the well-known result was used that provides internal stability and the desired quality of the output control. The unknown parameters of the control law within the selected structure are found using the new mini-batch adaptive method of random search (MAMRS). This new optimization algorithm combines the ideas of the adaptive random search and stochastic gradient descent methods. The examples of solving the tracking problem as a result of parametric optimization of controlling a bunch of trajectories are presented.
Approximate methods for H-infinity output feedback control
Authors: Panteleev A V , Yakovleva A A
Published: September 2020

The problem of finding Hm - regulators in the linear output control problem is considered. Sufficient IT -control conditions for closed loop control law depending on the state vector are formulated. Two approaches for approximate synthesis of the output feedback control systems are proposed. The first is associated with finding a pseudo-solution of the linear model of measuring system as well as with its use in control, the second one - with the synthesis of a state observer generating an estimate of the state vector and its application in control. The step by step algorithm is presented. It is shown that both of suggested methods provide the desired quality of transient processes and asymptotic stability in the model example. The approximate methods could be applied in autopilot design problems for aircrafts and rotorcrafts.
Trajectory Optimization of a Lunar Direct Landing from Halo-Orbits
Authors: Ivanyukhin A V , Korolevskiy E D , Starchenko A E
Published: September 2020

This paper illustrates the problem of optimizing the trajectory of a direct landing from a halo orbit to the lunar surface with given coordinates. The study is considered in circular restricted three body problem. The descent operation consists of two stages: change in velocity for descent from orbit (the descent is considered as an instantaneous change in velocity of a spacecraft) and the main stage of braking, which is considered as a task of optimal performance of the spacecraft with finite thrust. The formulation and solution of the optimal control problem is presented, as well as numerical examples illustrating the accessibility of various regions of the lunar surface and examples of landing trajectories.
Experimental study for stochastic pulse component of emission from stationary plasma thrusters in the radio-frequency range
Authors: Vazhenin N A , Plokhikh A P , Popov G A
Published: September 2020

This paper is a sequel to the authors’ publications devoted to the investigation of characteristics of self emission from electric propulsion thrusters. We consider the possibility of using the applications of the analytical signal theory and of the Fourier transform with a sliding window to study the spectral-temporal structure of the stochastic pulse component of the emission from stationary plasma thrusters in the radio-frequency range.
Colloid thrusters. Development status and prospects for application
Authors: Nigmatzyanov V V , Obukhov V A , Popov G A , Svotina V V
Published: September 2020

The article examines the principle of operation, the basic laws of electrostatic spraying of fluid, which constitutes the working process of colloid thrusters (CT). The features of two competing technologies for producing charged colloids based on the design of capillary type sprayers and the design of porous sprayers are considered. The experience of CT development and application is considered.
On the exoplanet obliquity variations in planetary four – body problem with evolving satellite’s orbit
Authors: Krasil’nikov P S
Published: September 2020

The evolution of the obliquity (the axial tilt) of a hypothetical exoEarth under the influence of gravitational moments from a star, a planet’s satellite in evolving orbit, and an outer exoplanet Evolution was investigated analytically. The exoEarth is assumed to be rigid, axially symmetric and almost spherical. The case where the orbits of two planets and satellite are given Keplerian ellipses while the satellite’s ellipse evolves on the lunar type was considered. The canonical equations describing the oscillations of spin axis of exoEarth were obtained. These equations contain one parameter (the longitude of the ascending node of the satellite’s orbit) slowly changing in time. Using the theory of the adiabatic invariant, approximate formulas for the precession angle and obliquity in time are obtained.
The problem of forecasting Earth pole trajectory when changing the average parameters of its motion
Authors: Perepelkin V V , Rumyantsev D S , Yan Soe Wai
Published: September 2020

The change of the Earth pole motion modes based on few-parameter two-frequency model has been investigated. It is shown that the effect of the change in the average frequency during the period of the Chandler and annual harmonics modulation leads to the change in the average parameters of the two-frequency model of the Earth pole oscillations. A method is proposed for detecting this effect by analyzing the phase variations of the observed Earth pole’s modulation.
A Godunov-type method for a multi-temperature plasma with the tabulated equation of state
Authors: Aksenov Alexey G
Published: September 2020

A multi-temperature code for a multi-component gas dynamic is considered. The velocities of components with nonzero mass are assumed to be identical to each other. The gas dynamic part is a Godunov-type method based on the efficient approximate solution of the Riemann problem operating with all components of the gas mixture. The method assumes the arbitrary table equation of state, but the system of the hydrodynamic equations should be hyperbolic. An arbitrary equation of state (EOS) can contain domains with a negative square of the sound speed c
2 = (dP/dρ)
a
at phase transitions. In that domains the gas enthalpy should be corrected to provide the nonnegative sound speed square. This work contains the test of the method on a strong shock wave in hydrogen plasma.
Packaging and unfolding of shells using highly elastic joints
Authors: Pestrenin V M , Pestrenina I V , Rusakov S V , Gilev V G , Buzmakova G V
Published: September 2020

A computational-experimental method for studying the packaging and unfolding of shell structures made of composite material is proposed. The construction consists of rigid elements interconnected by elastic hinges made of uncured prepreg. This material is elastic and therefore it can store an elastic energy during the structure packaging, and later a stored energy will facilitate unfolding. The hinge’s material is modelled by a hyper elastic isotropic medium, the Neo-Hookean potential is applied. The parameters of the potential are determined by the computational-experimental method. The viscous and viscoelastic characteristics of the binder are determined by the rheological method with a Physica MCR 501 rotational rheometer. The calculated effective properties of the hinge’s material are used to demonstrate the packaging of the cylindrical shell. Three different packaging methods for a cylindrical shell with six prepreg hinges are considered. The article studies the dependence of the load required for packaging on the type of packaging and the curing degree of the binder.
Effect of ablation at the inlet of submerged nozzle on discharge characteristics
Authors: Kirillova A N , Sabirzyanov A N
Published: September 2020

The effect of ablation on the discharge characteristics of solid rocket engines with submerged nozzles is examined. State-of-the-art computational fluid dynamics software package ANSYS Fluent is employed for simulation. The ablation is considered from the standpoint of the effect caused by uniform blowing of degradation products on the boundary layer developing over the entrance length of the submerged nozzle. Different masses of injected substance are considered. The impact of injection on velocity profiles is estimated. The discharge coefficient is affected by the non-isothermal boundary layer when degraded thermal protection material is injected and chemical reactions are neglected. The effect of injection on the profiles of velocity and temperature, and hence, on discharge characteristics is revealed.
Development and application of combined methods to expand the potential for predicting the defining characteristics of composites
Authors: Gusev E L , Bakulin V N , Chernykh V D
Published: September 2020

The issue of promising ways to expand potential opportunities for improving the effectiveness of methods for predicting the remaining life, durability, and reliability of composite materials and structures under the influence of extreme environmental factors is considered. Modifications of methods for searching for the global extremum of multiparametric functions have been developed and studied, taking into account the structural peculiarities of the efficiency criteria used in forecasting the remaining life and durability of structures made of composite and polymer materials. One of the promising ways to increase the potential opportunities has been analyzed. It is connected with the improvement of methods for constructing optimal directions for searching for the absolute minimum of efficiency indicators related to solving the problems of predicting the determining characteristics of polymer composites under the influence of extreme environmental factors and operational loads.