Table of contents

We are pleased to introduce the Proceedings of the XV International Scientific and Technical Conference "Applied Mechanics and Systems Dynamics" (AMSD-2021) organized by the Omsk State Technical University and held on November 9-11, 2021.

The object of the scientific and technical conference "Applied Mechanics and Systems Dynamics" is the analysis of the current state, trends and prospects for the development of applied mechanics and system dynamics with the aim of improving technology and production and creating new- generation equipment.

The conference addresses topical issues of development and research on the problems of mechanical engineering, strength and dynamics of mechanical systems.

List of International Program Committee, Organizing Committee, Organizing Institutions are available in this pdf.

All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

• Type of peer review: Double Anonymous

• Conference submission management system: Morressier

• Number of submissions received: 132

• Number of submissions sent for review: 132

• Number of submissions accepted: 108

• Acceptance Rate (Submissions Accepted/Submissions Received x 100): 81.8

• Average number of reviews per paper: 2

• Total number of reviewers involved: 20

• Contact person for queries:

Name: Andrey V. Shchelkanov

Email: avshchelkanov@omgtu.ru

Affiliation: Omsk State Technical University, Omsk, Russian Federation

Geometric correspondences and transformations can be applied in solutions to numerous problems of geometric modeling, mainly in order to create models of curves and surfaces. Among the tools of CAD systems, the geometric transformations are presented in the form of a limited set of editing tools, array tools, tools providing formation of 3D solids and surfaces through motion. In practice, this set of tools restricts application of the wide capabilities of geometric transformations and correspondences. In this regard, it is proposed to model the geometric transformations and correspondences via the geometry construction language. The elements of the geometric transformation theory are analyzed. The geometric transformations are proposed to be created on par with other objects of the geometric model. The commands of the geometry constructions language enabling construction of the transformation objects are considered, their application is discussed. Solutions to practical problems of surface modeling via the geometry constructions language with the use of geometric transformation are demonstrated on examples. The proposed approach allows us to facilitate modeling of curves and surfaces in CAD systems, if said curves and surfaces can be acquired through geometric transformation or correspondence that can be defined via a certain constructive algorithm.

The present paper details an approach to modeling of quasi-rotation surface segments with pre-defined conditions. The desired surfaces and their segments are formed parametrically through Maple computer algebra system. Various analytical approaches to trimming of the excessive parts of quasi-rotation surfaces are indicated. Geometric modeling is performed with use of a previously developed algorithm. An example illustrating the initial stage of design of an overpass between two separate buildings is provided. The design objective contains the basic geometric parameters of the desired architectural element. Three control models were created with the same initial parameters through basic CAD software methods. All of the constructed models are thin-walled. Mechanical properties of the scale 3D models of the target element were compared in equal conditions by means of CAD software. The prototype created through the use of a quasi-rotation surface segment was the most resistant to load. The paper also features a rendered concept of a complex of three towers connected with three overpasses. The acquired results allow us to conclude that quasi-rotation is an effective method of formation of models of architectural elements.

The method of analytical modeling and simulation of technological processes is presented, which makes it possible to assess the influence of external factors on the operation of information and control systems. The application of this method to study the process of detecting pipeline defects by vibroacoustic control systems is considered. A mathematical model with automatic selection of the parameters of autocorrelation functions of random disturbances is proposed, which makes it possible to take into account the influence of natural and man-made noises on the detection process. The possibility of modeling the influence of random disturbances on the working processes of technological machines is also considered. The proposed simulation models are of practical value, since they allow one to study virtual prototypes of construction and road-building machinery in various modes and reduce the cost of performing expensive field experiments.

In this article, the implementation of the method of parallel convergence in space in a computer mathematics system is considered and discussed. In this method, the pursuer's velocity vector is directed arbitrarily. The pursuer's trajectory gradually approaches movement in the plane formed by the line connecting the initial positions of the pursuer and the target, and the velocity vector. In this task, the target moves uniformly and rectilinearly. The pursuer moves evenly. The points of the pursuer's trajectory are calculated sequentially. They are being the result of the intersection of the plane containing the line of sight, sphere and cone. As we approach the plane where the target is moving, the algorithm for calculating the trajectory points changes. Now the point of the pursuer's trajectory is the result of the intersection of the sphere, the plane of movement of the target and the plane containing the line of sight.

This article is dedicated to the development of experimental data processing tools based on the geometric theory of multidimensional interpolation. At the same time, a scientific problem was solved, which is dedicated to the analytical determination of models of multifactor processes while maintaining the existing approach to experiment planning This makes it possible not only to use interpolation methods for the mathematical description of new experiments, but also to use the experimental data obtained earlier to improve their mathematical interpretation. The paper provides two examples that confirm the effectiveness of the proposed approach to constructing models of multivariate processes using multivariate interpolation methods. The first of the above examples contains two geometric models of the stress-strain state of metal polyhedral bent struts, which are presented in the form of ruled response hypersurfaces passing through 8 predetermined points in the 4-dimensional space. The second one is dedicated to the construction of a 2-factor process process using a 2- parameter parabolic geometric interpolant with subsequent optimization by methods of mathematical analysis of a function of two variables. As a result, the optimization of the aerated concrete manufacturing process was carried out to achieve the maximum values of the ultimate strength in compression after heat and moisture treatment.

The article provides information on hydrocarbon production in the Russian Federation, accidents at facilities supervised by Rostekhnadzor, and also presents a statistical analysis of the causes of accidents at high-risk facilities. Typical issues of studying the condition of the surface of an oil and gas object are considered on the basis of the electron-projection method that simulates the moiré effect and evaluates the surface topology by a system of of fuzzy inference rules implemented in the structure of a neural network.

The study was aimed at determining the sufficiency of the data obtained as a result of recording signals in the magnetotelluric sounding method. Based on the analysis of statistical methods and approaches to data processing and the characteristic properties of signals containing correlated and uncorrelated noise, a set of numerical indicators is proposed. These values can be used to assess the sufficiency of the data amount that will be used to obtain geoelectric structure. The key indicator is the coefficient describing the physical compliance of the apparent resistance, depending on the confidence intervals calculated at adjacent frequencies. The confidence intervals and the proposed coefficient can be used to make a decision about the statistical consistency of the gathered data and can be calculated in the data acquisition equipment.

The article discusses the issues of improving acousto-optical (AO) heterodyne laser displacement interferometers (LDI) by using two independent multi-frequency photodetectors: high- frequency (HF) and low-frequency (LF) low-noise, working with "fast inaccurate" and "slow accurate" measuring channels, respectively. The "fast inaccurate" channel allows you to measure displacements with high velocity peed movements. The scheme of the "slow accurate" channel is based on the joint operation of a phase-locked frequency system and a small-range phase meter, providing high resolution for low velocity. Such a scheme of AO LDI most fully implements its capabilities in the control of start-stop cyclic movements of objects, providing high resolution at the initial and final stages of movements with low velocity. A metrological analysis of the "slow accurate" channel is carried out, the possibilities and conditions for achieving AO LDI at low velocity of subpicometer resolution are shown.

The possibility of measuring air filter contamination by colourimetry methods is investigated. It is found that the optical density D_rel, measured relative to a clean filter surface can be used to assess filter contamination with coloured contaminant. This indicator is convenient for the specific weight of the contaminant in the range of 5-50 g/m² for substances with a density ρ < 1 g/cm³, and for the specific weight of the contaminant 10-250 g/m² for ρ > 1. It is shown that in case of a colour dust contaminated filter, the most reliable indicator is the colour difference ΔE of the contaminated surface relative to the clean one. The analysis of colour charts a*b*, a*L* and b*L* constructed in the CIE L*a*b*-1976 system shows that the lightness value ΔL* is appropriate to measure dark contaminants, and the value ΔE is acceptable for light contaminants.

The quality of printing products substantially depends on the accuracy of the individual mechanisms of the printing equipment. Since technological processes usually last in a period of a second, conventional measuring instruments turn out to be too inertial; therefore, to detect deviations of the given parameters (loads, locations, accelerations) from the calculated values, various sensors are used. The work is devoted to the selection of diagnostic tools for typical measurements used in print media equipment on printing equipment. Possibilities of parallel measurements and mutual analysis of signals of the designed diagnostic systems for research of parameters of the equipment of the print media industry are considered.

The reliability of the gas pipeline network is determined by the perfection of the structures, the precise fullfilament of the conditions of its operation, ensuring the coordination of the flow parameters in the pipe with the parameters of the blowers. Deviation from the established mode of operation in gas pipelines can affect the stability of the system. With a significant deviation from the operating mode, various features arise, both kinematic and dynamic deviations in the flow, which leads to unstable operation of the system. Therefore, it is necessary to automate the control processes of the pipeline gas network during gas transportation, which will be based on the results of mathematical modelling of mass transfer processes in pipes to determine the main flow parameters. It is also known that the main losses and changes in flow parameters in pipelines occur along the entire length of the linear sections of the network. Therefore, to adapt these changes to specific objects, it is necessary to use more accurate mathematical models that allow to adequately control the processes in the network based on automated control systems.

In the present paper geometric locus of points (GLP) equidistant to a sphere and a plane is considered; the properties of the acquired surfaces are studied. Four possible cases of mutual location of a sphere and a plane are considered: the plane passing through the center of the sphere, the plane intersecting the sphere, the plane tangent to the sphere and the plane passing outside the sphere. GLP equidistant to a sphere and a plane constitutes two co-axial co-focused paraboloids of revolution. General properties of the acquired paraboloids were studied: the location of foci, vertices, axis and directing planes, distance between the sphere center and the vertices, the distance between the vertices. GLP for each case of mutual location of a plane and a sphere constitutes: in case one passes through the center of other, two co-axial co-focused oppositely directed paraboloids of revolution symmetrical with respect to the given plane; in case they intersect each other, two co-axial co-focused oppositely directed non-symmetrical paraboloids; in case they are tangent to each other, a paraboloid and a straight line passing through the tangency point; in case they have no common points, a pair of co-axial co-focused mutually directed paraboloids of revolution.

The paper considers the geometric locus of points equidistant to two spheres of different diameters. If these spheres are concentric, the sought multitude constitutes a single surface – a sphere of diameter equal to arithmetic mean of the diameters of the given spheres. In other cases the geometric locus of points equidistant to two spheres of different diameters constitutes two surfaces. In case the spheres intersect, are tangent or distant to each other, the first of these surfaces is a two-sheet hyperboloid of revolution that degenerates into a plane in case the spheres are equal. In case the spheres intersect, the second of the surfaces is an ellipsoid of revolution that degenerates into a straight line if the spheres are tangent to each other. In the case of distant spheres, the second of the surfaces is a two-sheet hyperboloid of revolution. In case the spheres contain one another, the sough geometric locus constitutes two co-axial co-focused ellipsoids of revolution. The equations defining the mentioned surfaces are presented. The regularities in shape and location of these surfaces were studied; the formulas for the major and the minor axes of the ellipsoids and the vertices of the two-sheet hyperboloids of revolution were derived.

Discrete Fourier Transform (DFT) allows you to determine the discrete spectrum of a signal. Due to the presence of its high-speed implementation, called Fast Fourier Transform (FFT), this transform is widely used in digital signal processing (DSP). Most DSP tasks that deal with analogy signal and spectrum adapt the DFT to find the signal spectrum between harmonics. One of the most commonly used ways of such adaptation – the use of window functions. The analysis of standard window functions (Kaiser, etc.) showed that their direct application to solving the problem of estimating the parameters (frequency, amplitude, and phase) of nonharmonic sinusoidal components of signals leads both to the need for additional corrections of the estimation results and to additional errors in determining the phase of the signal. The paper proposes a method that allows building a window function without the indicated drawbacks based on standard window functions. The essence of the method is to transform the standard window function so that its spectrum does not contain imaginary components, and the amplitude of the fundamental harmonic would be equal to 1. The results of modeling the proposed method on the example of the Kaiser window showed that the phase estimate of the nonharmonic components of the spectrum using the obtained window function, in contrast to the estimate using standard window functions, is not displaced.

Road image analysis is an important task for automatic road inventory. The determination geometric dimensions for the road and the identification road objects are subprocess of constructing a road digital image. In this article, two algorithms for solving different subtasks of automatic road image inventory are proposed. The first algorithm identifies road signs. A convolutional artificial neural network is used in this algorithm. The training set for the neural network is prepared. A computer experiment to determine the recognition effectiveness of road signs has been conducted. The second algorithm defines the edges of the pavement. The algorithm consists five stages. The edges of the road are modeled as straight lines. The result allows you to automatically determine the width of the road.

The problem of cubic spline interpolation of functions with large gradients in the boundary layer is considered. It is assumed that the decomposition in the form of the sum of the regular and singular components is valid for the interpolated function. This decomposition is valid for the solution of a boundary value problem for a second order ordinary differential equation with a small parameter e at the highest derivative. An overview of approaches to the construction of splines, the error of which is uniform with respect to the small parameter e, is given. The approaches are based on the use of Shishkin and Bakhvalov meshes, which are thickened in the boundary layer region. An alternative approach based on a modification of a cubic spline with fitting to the singular component of the interpolated function is also considered. The comparison of the accuracy of the applied approaches with the performance of computational experiments is carried out.

The paper considered the signal processing of simplicial complexes. Hodge decomposition formula for discrete fields is given, which is similar to the Hodge decomposition formula for smooth vector fields. The construction and the estimation of the gradient, divergence and curl operators and Laplace matrices for discrete vector fields are considered.

The simulation model of the computational load balancing in a server complex using a balancing server is proposed. The server load balancing model was developed using MATLAB/Simulink/SimEvents/Stateflow tools. The SimEvents based model makes it possible to simulate the server complex as a queuing system and to take into account the sporadic occurrence of requests. The Stateflow based event-driven model simulates the system with a variable time delay in data transmission channels and simulates state transitions for servers. This discrete-event simulation model allows evaluating the possibility of rational use of computational resources and reducing the time of service. In addition, the model allows to investigate the effectiveness of load balancing systems at the stage of their development.

Calculation of the cutoff probability in the Rand-ESU method. Identification of weak points of the method through the random sampling of spanning trees, also the Rand-ESU method with has implemented in the igraph library. Implemented in library igraph. Comparison of methods for counting subgraphs at four vertices. Prospects for the development of the spanning tree sampling method.

The article is devoted to the problem of identifying factors directly or indirectly influencing the presence of obstructive sleep apnea syndrome in patients (OSAS) and solving the problem of pattern recognition in the factor space using the example OSAS. A factorial study was carried out for each group of indicators characterizing the condition of patients with OSAS, optimal factor structures were formed and the interpretation of the identified latent-integrative factors was carried out. It was implemented Bayes' formula for calculating probabilities by OSAS groups in factor space. It is proposed formula for the transition from initial data to factors for finding the n-dimensional distribution density which is necessary for solving problems of recognition and based on the Bayesian criterion. There are given the proof of the transition formula and computational algorithms for the recognition problem.

The purpose of this article is a mathematical description of the DDoS-attack with the help of the differential game theory. The attacked computer system which has a performance limit is mathematically described. The hacker attack is successful if this limit is reached. The system administrator's strategy is successful if he can prevent the server from "falling". We find this strategy. Then we study an optimal Stackelberg strategies of hierarchial "administrator–hacker" game.

A method of numerical solution of one-dimensional problem of cylindrical shear wave propagation in an elastic and elastic-plastic soil is developed in the article using the finite difference method. The numerical results obtained are presented in the form of graphs. From the results obtained, the attenuation of the parameters (shear stress, shear strain, and angular velocity) of cylindrical wave propagation with distance in an elastic and elastic-plastic soil was determined. The attenuation of waves with distance is justified by the dissipation of strain energy on the expanding cylindrical soil layer. In the case of load exceeding the elastic limit, plastic strains occur in soil near the point of load application. The boundaries of elastic-plastic strain of soil are determined.

Austenitic chromium-nickel steel AISI 304 is used as a structural material for heat exchange equipment. Long-term operations result in degradation of mechanical properties of material due to formation of chromium carbides at grain boundaries. The influence of various thermal ageing modes of AISI 304 steel on mechanical properties with metal fragments of reactor plant on fast neutrons of RP BN-600 taken as an example after long-term operation has been investigated.

In this paper discussed the problem of constructing and training a fuzzy neural network based on fuzzy logical rules. Based on the constructed model, the developed algorithm, the objects classified with indistinct initial information. Under these conditions, traditional methods of mathematical statistics or simulation modeling do not allow building adequate models for solving data mining problems. We consider the solution of problems based on the use of intelligent modeling technologies using methods of neural networks and fuzzy logic in order to automate the construction of fuzzy rules based on methods and algorithms of machine learning.

The paper considers development of a model for determining the optimal amount of urban passenger transport. When modeling transport systems, the main task is to find the optimal amount of passenger traffic, which is a complex consisting of a mathematical model, an algorithm and a software product with information support for the integrated planning of the system of public transport routes and determining the rational volume of traffic.

Mathematical methods in medicine - the criteria for determining the status of research objects related to medicine and health problems, methods and algorithms for assessing, analyzing and forming a set of quantitative variables are analyzed. Because of the analysis, problems and tasks were identified that need to be addressed.

The paper presents a method for optimal initial allocation of resources of a dynamical system and reallocation of resources at the control interval. The main types of practical tasks on the exchange of material, energy and information resources are considered. A general scheme is given for their formalization using a special extension of the dynamical system of the original problem. The results of verification simulation experiments are presented.

Water spray evaporation in a hot air flow is a common process for many industrial applications. Spray nozzles should be well adjusted and distributed specifically to achieve efficient evaporation. The present study addressed simulation of the process within the Eulerian-Lagrangian workframe with k-∈ turbulence model. Simulation was carried out via OpenFOAM and postprocessed with ParaView. SprayFOAM solver was used to obtain a solution for 2D and 3D representations of the wind tunnel. Custom JANAF-based approximations were introduced for thermophysical properties of working mediums (air and water vapor). Obtained results were accurate enough to validate the presented model against adopted experimental data. Drift eliminator was modelled with virtual interfaces (baffles), which were tested in two scenarios: accumulating and removing droplets from the computational domain.

The problem of reconstruction of dependencies using locally adaptive linear regression models is considered. The problem of a priori optimal design of experiments during identification of locally adaptive linear regression models is solved. In this case, the region of determining the active factors is divided into 2 or 3 fuzzy partitions. The problem of constructing D-optimal designs of experiment is formulated and solved

The article considers an approach to the processing and analysis of biomedical data from clinical examination. An automated diagnosis system is presented to be applied in liver disease diagnosis by the results of the initial examination of patients using a classifier based on fuzzy inference. The research is carried out by modeling the proposed system in the environment MATLAB FuzzyLogic. The regularities are revealed making it possible to normalize the results of laboratory tests depending on gender characteristics and to increase the percentage of correctly determined disease stages.

One of the well-known classification problems in machine learning is the problem of recognizing handwritten numbers. This task is solved, since there are different neural networks that determine with fairly high accuracy which number is shown in the picture. In this paper, we will consider the recognition of handwritten digits subjected to certain deformations.

For a long time there have been many neural networks that are able to recognize handwritten numbers. In our work, we will investigate a neural network according to a specific feature, indicating the number in the picture. We will try to achieve an important image skeleton for recognition.

The article discusses the technology of automated formation of SKOS-ontologies for semantic modeling of the subject area, based on natural language texts analysis. The technology is based on neural network and distributive (vector) language models. A brief description of the content and formulation of the problem of extracting concepts and relations from natural language texts is given, the results of constructing a neural network classifier of SKOS relations using the Glove vector model, as well as an example of using the technology to construct a fragment of an applied SKOS ontology are given.

A two-dimensional linear elliptic equation with regular boundary layers is considered in the unit square. It is solved by using an upwind difference scheme on the Shishkin mesh which converges uniformly with respect to a small perturbation parameter. The scheme is resolved based on an iterative method. It is known that the application of multigrid methods leads to essential reduction of arithmetical operations amount. Earlier we investigated the cascadic two-grid method with the application of Richardson extrapolation to increase accuracy of the difference scheme by an order uniform with respect to a perturbation parameter, using an interpolation formula uniform with respect to a perturbation parameter. In this paper a cascadic multigrid algorithm of the same structure is studied. We construct an extrapolation of initial guess using numerical solutions on two coarse meshes to reduce the arithmetical operations amount. The application of the Richardson extrapolation method based on numerical solutions on the last three meshes leads to increase accuracy of the difference scheme by two orders uniformly with respect to a perturbation parameter. We compare the proposed cascadic multigrid method with a multigrid method with V-cycle. The results of some numerical experiments are discussed.

To ensure the effective functioning of the university educational environment, document flow processes automation, which includes the task of documents automatic classification, is of great importance. The article considers the task of classifying university documents by machine learning methods in order to improve the quality of classification. Documents preprocessing was carried out, which made it possible to distinguish significant words in documents, due to which the accuracy of documents classification increased. Described are methods of extracting features from text TF and TF-IDF, which determine keywords by words frequency included in document. A modification of the TF-IDF method is proposed, which consists in calculating the words importance depending on their part of speech. This made it possible to improve the classification quality by highlighting only important and significant words in documents. Suggested is a classification algorithm using a method of support vectors to reduce the documents number involved in classification and a method of k-nearest neighbor for classification. The advantage of this algorithm over the described analogues is shown, which is expressed in the number of mistakenly classified documents decrease.

An overview of approaches to the construction of two-dimensional interpolation formulas for a function of two variables with large gradients in the boundary layer regions is given. The problem is that the use of polynomial interpolation formulas on a uniform grid can lead to errors of the order of O(1). It is shown that the use of polynomial interpolation formulas on the Shishkin and Bakhvalov grids leads to the fact that the error becomes uniform in a small parameter. More accurate results are obtained by using the Bakhvalov grid. It is shown that on a uniform grid it is possible to successfully apply interpolation formulas that are exact on the singular components responsible for large function gradients in boundary layers. Numerical results are given.

Swirling flow of heat transfer fluid in heating facilities is a compelling way to intensify heat transfer augmentation. The paper considers the process of passive swirling flow in heating pipes by way of application of special design pipe connectors. Numerical simulation has been accomplished on the basis of viscous incompressible fluid model represented by Navier-Stokes equations complemented with temperature transfer equation. Numerical experiments has been completed with the help of applied software OpenFOAM based on finite volume method.

The problem of asymptotic fluctuations of temperature and moisture content in a half-space is solved by the method of complex amplitudes. The material filling the half-space consists of a solid base (capillary-porous body) and water. The well-known Fourier solution for temperature fluctuations in half-space in the absence of moisture and under the boundary conditions of heat exchange of the first kind is generalized to the case of a wet material under the boundary conditions of Newton for temperature and Dalton for moisture content. The results of the work can be used in geocryology to model seasonal fluctuations in the thermophysical characteristics of frozen rocks and soils.

The authors proposed an induction heating system for an extended pipeline, which implements the technology of local-associated heating, using the methods of functional integration. The authors carried out a study of the technology of local-associated thermal effect on an extended pipeline. We have developed a technical solution for a system of local-associated induction heating of a long pipeline using functional integration methods. We also developed a computer model of the system in the ELCUT 6.4 software package. The authors evaluated the efficiency of the heating process and obtained the characteristics of the magnetic field of the system as a result of modeling. We have solved a thermal problem that demonstrates the efficiency of the local heating technology.

The article considers the processes of deposits formation on the walls of heat exchangers. Experimental studies of the composition and structure of deposits in heat exchange equipment elements are carried out. The regularities of deposition are studied. The possibility of virtualization of deposits monitoring sensors is analyzed. The conclusion is made about the possibility of analytical prediction of the behavior of heat exchange equipment during the deposition and their influence on the heat transfer process. A partial replacement of experimental physical and chemical studies by simulation is proposed.

With using the mechanics of multiphase media, the process of extraction of moisture from a dead pore is considered. The study was carried out by numerical simulation. Two-dimensional approach of interaction of the air flow with droplets without taking into account the processes of heat and mass transfer was considered.

While lifting a payload, boom machines perform a useless job to overcome gravitational forces of the working equipment gravity force. The piston spring, injected with compressed air to a pressure of p_w =10-15 MPa, ensures balancing gravitational forces of gravity during vertical movements and eliminates the indicated disadvantage. The piston air spring, independently mounted in the boom machine working equipment, represents an energy saving unit. A detailed analysis of physical processes of obtaining high-pressure compressed air for the injection into the air spring has been conducted, new solutions have been obtained, connected with the technology of air compression to high pressure, satisfying definite design requirements.

We consider two classic problems: the Traveling Salesman Problem and the p-Median Problem. In both problems the total traveling cost (in some sense) is minimized, assuming that all traveling times are known. In most real-word applications the input data are uncertain, and this fact should be taken into account when a solution is constructed. In this paper we investigate bi-objective versions of the problems, where the total cost and fuzzy uncertainty associated with the traveling times (membership function) are optimized. A greedy approximation algorithm is proposed and experimentally tested on instances from TSPLIB library.

On the example of modeling thermodynamic processes occurring in the on-board gasification system (OGS) of unprocessed liquid fuel residues in the tanks of the launch vehicle stage (LV), using a reduced physical model of the fuel tank – an experimental model installation (EMI) as part of an experimental stand (ES), the design parameters of which are determined (geometric parameters, coolant and characteristics of the model fluid) based on the theory of similarity of thermophysical processes occurring in the real design of the fuel tank of the LV stage according to the criteria of Reynolds, Nusselt, Prandtl, methodological recommendations are proposed to improve the quality of the process of theoretical and experimental research at the stage of scientific research (R&D).

The article discusses various possibilities of using an electrodynamic drive with an increased displacement of a movable permanent magnet as a low-frequency inertial compensator of vibroactive forces.The main attention is paid to the analysis of an active dynamic vibration damper (ADVD) when installing an electrodynamic compensator (EDC) on the base near vibration supports and when connecting the EDC moving mass with a vibroactive mass using a spring. It is shown that the considered ADVD is effective as a vibration isolator in the low-frequency range.

One of the most perspective methods of hardening is friction stir processing. The study shows processing methods based on the friction stir principle. The results of hardening of tool steels 1089 (Fe97%, C0.8%), 3343 (Fe80%, C0.9%, Cr4%, Mo5%, W6%, V2%), 440C (Fe78%, Cr18%, C0.95%) are presented. As a result of hardening, it was possible to increase the microhardness of carbon tool steel by more than 3 times, and also to achieve a decrease in the average grain size in the treated area by more than 10 times in relation to the base material. It is proposed to use the FSP in the manufacture of cutting tools from tool steels to increase physical and mechanical properties.

Friction stir welding (FSW) is best suited for welding large-sized aluminum alloy parts. Finding optimal welding conditions and methods for minimizing defects arising during welding is an urgent task, the solution of which is necessary for the commissioning of FSW technology into the industry. The introduction of this method for welding rocket fuel tanks will increase the productivity of manufacturing products and their strength. The aim of this study is to improve the quality of friction stir welding of 7,6 mm thick Al-Mg6% aluminum alloys, as well as to increase productivity. The aim is achieved by finding optimal welding conditions and modernizing the welding method for simultaneous stripping by milling. The optimal welding modes found as a result of the study allow ensuring the strength of the welded joint, reaching 98% of the strength of the base material. The modernized welding method allows milling (deburring) to be carried out simultaneously with welding, which can significantly reduce the manufacturing time of the product, for which deburring is a necessary operation. As a result of the study, the welding modes were also revealed, leading to the appearance of hidden defects, which can reduce the strength of the welded joint by 2 times. A conditional diagram showing the appearance of defects in various combinations of modes has been compiled.

The use of modern resource and energy-saving technologies in multifactor technological processes is a promising direction that allows improving the design and technological support of the manufacturing sector in most developed countries. The use of an electrochemical installation - aeroponic installation with automatic control system in industrial processes allows to reduce the consumption of the working solution. It is a more energy efficient process compared to traditional production technologies. The article describes the results of the development and creation of an automatic control system for technological processes in an aeroponic installation. The results of research on ensuring the strength and wear resistance of the elements of the system for supplying the working solution in the form of an aerosol using nozzles are presented.

The work considers the dynamics of a composite nanosatellite with variable inertial-mass parameters. The nanosatellite consists of two units connected to each other by flexible rods, a main unit (nanosatellite body) and a mobile unit. A passive system for stabilizing the rotational motion of a composite nanosatellite is considered, which uses a mobile unit as a motion control actuating element.

The article is devoted to the development and research of a supercapacitor based on an aqueous electrolyte. The review of the current state in the field of energy storage is carried out. The processes occurring in the supercapacitor are considered. Sheets of paper with different carbon concentrations have been created. The design of the housing has been developed with the possibility of replacing the plates and electrolyte. This is an advantage in the process of conducting experiments. According to the results of the study, a prototype supercapacitor based on NaCl electrolyte with a capacity of 9F and a maximum output voltage of 1.2 V is presented.

The article is devoted to the measurement of the ion beam velocity of an accelerator two-gap ion thruster. A theoretical representation of the physical process of capturing charged particles using a cylindrical sensing element is given. A schematic diagram and a printed circuit board for detecting an accelerated ion beam have been developed. The expression for calculating the signal current of the sensing element is defined. A condition for capturing charged particles using the critical mobility of charges is formulated.

The description of experimental benches for combustion of demonstration elements of material samples - combustion demonstrators (CD) is given. CD for investigating thermodynamic processes during combustion on experimental benches are developed. The results of experimental studies of combustion of CD made of different materials (existing and synthesized) are presented. A new direction of research is formulated - the development of combustible materials and structures made of them, providing the specified characteristics at all stages of operation.

Fire detection system call points types selection is determined by the gas-smoke environment prevailing physical parameter in fire case and by this parameter change dynamic as combustion develops. Obtaining of practically important information about the gas-smoke environment prevailing parameters during a fire, their changes dynamic and the time when they reach the threshold values for call points for real objects is possible on the numerical studies results basis using the FDS program complex modeling heat and mass transfer and gas dynamic processes occurring during a fire. The performed calculations made it possible to obtain the temperature dependences, smoke optical density and carbon monoxide concentration in the near-ceiling area on time since the ignition start for a number of characteristic rooms for various purposes. The call points type choosing ambiguity for rooms with different fire load indicators is shown. The calculated data can serve as a basis for choosing the fire detection system call points types, as well as for setting up and effective functioning of multi-sensor and multi-criteria fire detectors.

Modern warning and people evacuation management systems in case of fire are able to implement different notification options (with a start evacuation delay) and different people groups routing, which reduces their flows density and the critical congestions formation probability on the evacuation routes. For these systems potential technical capabilities practical realization, warning and evacuation algorithms are required in accordance with the fire source location, the combustion development dynamic, the characteristic parameters of the object and the evacuating people. Such algorithms generation is possible on the basis of information about the current values and fire hazards increase dynamic in the premises and on the evacuation routes. The necessary information can be obtained as a result of numerical studies using software tools that implement mathematical models of heat and mass transfer and gas dynamic processes, as well as the evacuating people flows movement processes in case of fire. One of the algorithms examples for alerting and evacuating people for the educational institution building is presented. The calculated data make it possible to predict and evaluate the people safe evacuation fundamental possibility in case of fire and to propose space-planning, technical and organizational solutions and measures for its successful implementation.

Reducing the uncontrolled deviations of the payload moved by a crawler crane with a constant boom length is a relevant objective, since it improves the operational efficiency and safety, as well as the positional accuracy of the payload at the target point. In this regard, the results of the research aimed at developing a trajectory synthesis method of two controlled coordinates of the crane, such as the swing angles of the rotary platform and boom raising which ensure a predefined trajectory of the moving payload, have been described. Furthermore, the influence of the payload movement parameters, such as the time of the prescribed payload displacement, the initial angle of the boom lift, the hoist rope length, the overall dimensions of the required payload displacement trajectory on the error of the predefined payload trajectory execution by the lifting crane has been studied. For example, we examined a predefined arc curved trajectory of the moving payload. The horizontal coordinates of the trajectory of the upper suspension point located on the boom head and providing the predefined payload trajectory were generated using the Matlab mathematical simulation model developed in the Simulink package for solving a linearized differential equation. This equation describes the deviations of a pendulum suspended payload with a horizontally moving suspension point in a separate vertically located plane of the space. The superposition of two horizontal trajectories obtained by solving the given equation ensures the payload movement along a curved trajectory predefined in the horizontal plane. The trajectory of the crane's controlled coordinates was calculated from the horizontal coordinates of the suspension point. When executing the trajectory, the examined additional errors occur. It was revealed that when the time of moving along a predefined payload trajectory exceeds 40 seconds, the residual oscillations become insignificant and payload positional accuracy at the target point increases. It suggests the limited applicability of the developed method when implemented on the rotary lifting cranes with a constant boom length. The range of the local minima errors of the predefined trajectory implementation depending on the initial inclination angle of the boom, which varies in the average values range of the boom inclination angle, has been defined.

Reducing the vibration effects on the operator of a construction, road and other machines is a relevant objective, since its accomplishing improves the efficiency and accuracy of the work performed by machines and reduces the risk of operators' occupational diseases. Vibration protection systems with the effect of quasi-zero stiffness are promising. To produce this effect, Belleville springs packages can be used. They are a way to create a simple, reliable and inexpensive passive mechanism of the vibration protection system of the operator's seat. The influence of the static characteristic center slope of two Belleville springs packages on the maximum acceleration of the load under the sinusoidal kinematic excitation of the seat base movements is investigated. The static characteristic center slope of the spring packages was characterized by the coefficient that affects the type of the static characteristic according to the known analytical expressions for the separate spring force. To obtain the chair acceleration values in a fixed coordinate system, we used a simulation mathematical model developed in the Simscape Multibody package for modeling mechanical systems of the MATLAB mathematical system. The model used blocks of a fixed coordinate system, a sliding joint and a rigid body forming a chain. The maximum acceleration of the chair in a fixed coordinate system was defined during a predetermined period of time at the end of the transition process under the steady state oscillations. When conducting the computational experiment, the specified oscillations amplitude of the chair base and the angular frequency of these oscillations varied. For a proper comparison of the experimental results in the form of graphical dependencies of the maximum acceleration on the amplitude and frequency, the ranges of acceptable and unacceptable arguments combinations were selected for the two spring packages. The combinations of amplitude and frequency were considered unacceptable when the maximum deformation of the spring package went beyond the static characteristic maximum. For the two packages of springs, the acceptable regions were different, therefore their intersection used for the comparative analysis, was obtained. The springs package with a relatively high stiffness in the center of the static characteristic is found out to generally provide better vibration protection of the chair in the entire acceptable range of arguments. Simultaneously, a package with lower stiffness in the center of the characteristic dampens vibrations better in the small amplitudes area, i.e. when operating in the quasi-zero stiffness area.

The paper considers the vibration isolation problem of the construction and road vehicles operator's seat with prescribed sinusoidal displacements of the seat base. This problem is highly relevant, since the road construction vehicles operation with soil, loads, road surfaces, etc. is accompanied by the strong vibrations. The investigation was carried out in terms of the influence of the suspension static power characteristic shape on the maximum vibration acceleration of the seat. Many antivibration mechanisms have a similar static characteristic. Currently, one of the promising directions in the development of the antivibration systems is the implementation of the systems with a quasi-zero stiffness section of the static power characteristic. Such systems are preferred to dampen the low-frequency vibrations. In this paper, we study the systems having a three-segment static characteristic, which middle segment is a horizontal straight line corresponding to a section of quasi-zero stiffness. However, two extreme segments providing the braking and stopping of the mechanism when going beyond the boundaries of the quasi-zero stiffness section were described by Hermite splines with a maximum second-order derivative. The analytical expression of such a two-point spline makes it possible to set not only the function values at two boundary points, but also the values of the first two derivatives of this function at the same points, i.e. to vary the shape of such spline within a wide range. This has made it possible to consider several dozen combinations of such splines having different values of the first derivative at both boundary points, i.e. to study the differently shaped static power characteristics of the antivibration mechanism of the seat under the same sinusoidal influences. The sum of accelerations calculated for a sample of the specified seat base vibrations from the amplitude and time values combinations was used as the assessment and evaluation criterion of various static power characteristics. Furthermore, the amplitude and time values combinations, at which the maximum value of the antivibration mechanism displacements exceeded the limits of at least one of the static characteristics, were excluded from consideration and were not taken into account when calculating the criterion values. The criterion minimum value was found out to be reached at zero value of the first force derivative at the internal boundary points of the external characteristic segments, at the maximum value of the first force derivative at the external boundary points of the external characteristic segments. In this case, the first force derivative has no discontinuities on the entire static force characteristic curve. The given static characteristic is optimal according to the accepted criterion. The value of the acceleration sum criterion can be decreased fourfold in the studied range of the first derivatives from zero to twenty thousand Newton/meter.

The paper considers the issues of mathematical modelling nonlinear vibrations for the wall of a narrow parallel walled channel filled with a viscous incompressible liquid. The upper channel wall is a rigid rectangular plate supported by nonlinear spring with a cubic restoring force, while the bottom one is a fixed rigid rectangular plate. The case of nonlinear oscillations of the upper channel wall due to channel's foundation vibration has been investigated in the frame of hydroelasticity problem. The main attention is paid to the consideration of steady-state nonlinear oscillations for the upper channel wall and the creeping motion of the liquid in the channel. The liquid layer reaction acting on the upper channel wall is found and the channel's wall nonlinear oscillation equation is obtained taking into account the energy dissipation due to the liquid viscosity. It was shown that this equation coincided with the Duffing one. The solution of the nonlinear oscillation equation was carried out by the harmonic balance method. Based on the found solution, the hydroelastic response of the channel wall on a nonlinear elastic suspension to the channel foundation vibration was determined.

Impact loading of a barrier from ductile material is considered. It is postulated that deformation process can be modeled two independent interfaced tasks: deformation of a barrier as plate of final thickness from elastic and viscous-plastic material the hard puncher and evaluation of energy loss of the puncher on material deformation under it and overcoming force of front resistance. It is shown that on the one hand, losses of energy of the puncher on barrier material deformation by longitudinal waves of tension both on formation, and on a stopper cut, and with another are most significant, process of promotion of the created stopper is longest and determines generally time of breaking through the barrier.

Effect of strain rate, quantity of plastic deformation and temperature of material on characteristics of material at electromagnetic forming is considered. It is shown that strength characteristics increase with growth of strain rate, and the plasticity increases with an increase in the value of plastic deformation and temperature. The variant of writing of the constitutive equation considering these changes is offered, and its use in calculations can significantly increase efficiency of calculations of operations of electromagnetic forming.

The paper analyzes the capabilities of an automatic rotary platform of the "Flyuger" type to reduce micro-accelerations in a protected area when it is installed on a small spacecraft of the "Aist-2" type. The micro-accelerations field of the working volume of scientific equipment of the "Growth installation" type has been modeled. The comparison with flight test data is made. The results of the work can be used in the design of small technological spacecraft.

This article considers the possibility of using seismic supports in seismic protection systems for ball tanks for storing liquefied hydrocarbon gases in seismically unstable operating conditions. Attention is paid to the study of support structures, which include rubber-metal vibration isolators. Based on the theory of long-term strength, the issues of the operability of rubber-metal seismic-insulating supports (RMSS) are considered. The use of RMSS reduces seismic loads in the supports of the tank by 1.5-2.0 times. At the same time, the analysis of the stress-strain state (SSS) of the tank body showed that the structural elements retain their operational characteristics under seismic load and meet the strength conditions in accordance with the requirements of the current standard technical documentation.

The work is devoted to the description of an algorithm for the formation of the internal structure of a product, obtained using the FDM technology, considering the stress-strain state, based on the use of isosurfaces of equivalent stresses obtained on a pre-calculated stress-strain state of the sample in an elastic isotropic formulation. In addition, the preparation of a force structure based on isosurfaces of normal stresses, considering the problem of axial tension/compression of horizontal layers of the sample, typical for the problem of four-point bending, is described. Numerical simulations in ANSYS Workbench have obtained results showing the performance of the optimized design, using the example of the four-point bending problem. Comparison of the results of numerical modelling, optimized and monolithic samples, in elastic isotropic formulation is presented.

The results of experimental studies of the rolling stock traction electric motors collector profile are presented. A technique is shown for combining collector's profilograms in the cold and hot state for non-synchronized values of the origin. A new diagnostic parameter is proposed for assessing the state of the traction electric motors collector profile - the root-mean-square value of the difference in the relative heights of the collector plates in cold and hot states. The changes comparison results in the proposed diagnostic parameter for traction electric motors after repair in a locomotive repair depot are presented. The analysis of the influence of the collector formation on the state of the rolling stock traction electric motors collector profile is carried out. It is shown, that the change in the collector profile can be caused by two reasons - poor-quality forming, as well as poor-quality repairs.

This article reflects a study of the operation of a hydraulic drive with nonlinear characteristics of an axial piston hydraulic motor, which operates at the lower limit of the speeds of the executive bodies. A nonlinear frictional moment arises in the end valve of the hydraulic motor connected to the actuator and leads to movement with stops. The mathematical models of the dynamics of the hydraulic drive, proposed in this study, are linearized by the method of harmonic linearization and allow engineering calculations of the parameters of the modes of non-stop motion. Evaluation of the dynamic properties of the hydraulic drive, corresponding to the onset of an unstable mode, makes it possible to determine the minimum value of the constant component of the speed of the executive body.

The dynamic stability of pressure regulators in hydraulic systems of technological machines is considered, in which additional hydrodynamic forces arise in unsteady modes. The magnitude of these hydrodynamic forces is determined mainly by the first derivative of the flow rate through the throttle slot of the regulator in time. Experimental studies of pressure regulators have shown that hydrodynamic forces, depending on the switching scheme and the design dimensions of these devices, can affect their stability in various ways.

The paper presents the results of research to determine the dynamic component of the force of the jet stream of a microwave ion engine. The dynamic component was determined by an adiabatic calorimeter based on a heat flux density sensor. Experimental studies have shown that with a working fluid consumption (nitrogen) from 0.01 to 0.08 mg/s, the thrust of the micro-motor was from 1.45 to 13 μN. The calorimetric method gives inflated thrust values presumably due to ohmic heating in a DC glow discharge.

This paper presents the results of an experimental study of the jet thrust of ionized nitrogen flowing from the working chamber of an experimental sample of an accelerator ion thruster into a vacuum space. The resonant aerodynamic method (RAM-method) was chosen as the main research method. A method for determining low thrust and the design of a stand for implementing the RAM- method are proposed. The object of research is a prototype of an accelerator two-gap ion thruster with a solid-state microwave plasma generator and a toroidal resonator. The study showed that a 2.5 W microwave generator together with a 2.5 W accelerating potential difference voltage source at a nitrogen consumption of 0.1 mg/s creates an ion jet, the speed of which reaches 100 km/s. The current of the ion jet was 5.5-6 μA. The jet thrust was 0.141-0.188 μN.

Additive manufacturing makes it possible to speed up the process of manufacturing a product using a CAD model many times over. This advantage is effectively used in the manufacture of small batches of products with complex surfaces in the automotive and aviation industries. Improvements in printers are needed to improve accuracy and productivity. Traditionally, delta kinematics are considered to have advantages over sequential linear kinematics due to their high travel speed and relatively low cost. However, delta kinematics has received limited application, mainly for personal FDM printers. The article attempts to understand the advantages and disadvantages of delta kinematics for use in 3D printers. For this, the displacements and velocities were simulated for four examples of motion trajectories. The analysis showed that the average speed of movement of the extruder is approximately equal to, and in some cases less than the linear speeds of movements along the rods. At the same time, to ensure a uniform speed of the extruder, significant accelerations are required along the individual rods. This leads to vibrations and ultimately limits the maximum speeds.

2D films deformations under action of ferroelectric substrate by computer modeling method are performed in article. The film has a square lattice. We use harmonic law for the energy of interatomic interaction. The substrate effect on the film is simulated by the 2D Frenkel-Kontorova potential. The orientation of the film and the substrate do not match. Different cases for periods of film and substrate are considered. The Monte Carlo method is used for computer modeling. If the period of the film and the substrate coincide, the film atoms are placed at the minimum points of the substrate. The film on the substrate has a square crystal lattice. If the period of the substrate is less than the period of the film, the continuous film is converted into a film 2D nanoparticles. The substrate potential amplitude affects the filling of the space between particles. If the period of the substrate is longer than the period of the film, a superstructure in the form of a periodic lattice with an increased particle concentration is formed in the film. The distribution of atoms in the superstructure is determined by the substrate potential amplitude of the substrate potential.

The efficiency of the solid-phase activation of modifying complexes has been evaluated. It is shown that such preliminary treatment of refractory particles leads to a significant increase in the diffusion coefficients in the matrix of the metal-ultrafine powder complex. The introduction of modifying complexes that have undergone solid-phase activation into liquid nickel increases the degree of supercooling of the melt and reduces the grain, which characterizes a high degree of intensity of the action of inoculators. In this case, the most intense effect is exerted by the addition of the TiCN-Ni and TiCN-Ti complexes that have undergone solid-phase activation.

Mechanical, technological and operational properties of metal materials are largely influenced by changes of concentrations, morphology, dimensions, localization, elemental and phase composition of dispersed precipitates. This paper is devoted to a study of dispersed carbides of submicron size at tempering of high-strength medium-carbon steel. The main emphasis is on comparing the data obtained by small-angle neutron scattering and transmission electron microscopy. As a result of the analysis, it was found that carbide growth begins in the investigated steel immediately after quenching when the tempering temperature increases. First, it is fixed by a transmission electron microscopy and a small-angle neutron scattering and then above ~ 300 ° C carbide growth is fixed by neutron diffraction. The residual austenite is also completely dissolved by the time the temperature reaches ~ 300 °C. A good matching has been reached for the methods used. It has been shown that a complex use of integral and local methods allows to obtain fully information about the structure and properties of the investigated material.

The present work studies Ti/TiB2 system of metal matrix composite powders and coatings obtained on their basis by microplasma spraying. Ti/TiB2 is the system of potentially perspective materials being operated in aggressive environments. Morphology of the micro-grinding of the composite powder and coating was investigated by a scanning electron microscope, with the distribution assessment of the reinforcing component. The phase composition and its evolution in the composite powder and coating were also studied.

The present work investigates the influence of conditions like the climate of the Arctic shelf, such as aggressive medium, hydroabrasive wear and variable temperatures on Ti/TiB₂ composite coatings. The applicable composite powders were investigated with the use of thermogravimetric analysis. The values of corrosion resistance and wear resistance of the coatings were also investigated.

In this work we have studied the behavior of oxygen adsorbed on the MXenes M₂CO (M=Ti, V, Nb) surface by the density functional theory and Monte Carlo methods. An approximation for the lateral interactions potential has been constructed that has the form of a pair potential. We have carried out the quantitative assessment of the errors of the pair potential. Using SuSMoST program we have constructed isotherms of adsorption. The results showed a non-trivial phase behavior of the adlayer: we observed three phases characterized by the 1/3, 1/2 and 2/3 coverage. It has been predicted that complete oxygen removal from the MXenes surface is possible at temperatures above 500 K.

A comprehensive study of the structure and phase composition of a promising brand of electrically conductive carbon black was carried out. It is shown that the material under study has a complex phase composition, which, along with carbon, includes other elements and compounds, such as sulphur, oxygen, nitrogen, and vanadium oxides. The structural state of carbon black can be defined as amorphous. The presence of functional oxygen-containing groups in the material, presumably attached to the edge carbon atoms of graphene layers, has been proved. The interrelation of some characteristics of the structure and phase composition of the material and the properties of polymer composites is discussed.

The work carried out definitive tribotechnical tests of the systems of materials "CuCrNiZrTi - 85W90 - 40X", "CuCrNiZrTi - 85W90 - KCh50" to assess the nature of the manifestation of the effect of additive compositions (AC) ABRO GT-409 and POLYTRON^TMC on adaptability to loading and lubrication modes parameters of adhesion properties when modeling shear on small samples. It was found that at the stage of running-in, the systems of materials operate stably with clearly pronounced tendencies to reduce the sliding resistance to a certain minimum, followed by its increase due to the influence of the AC components. ACs do not determine the effect of reducing the wear intensity in the investigated range of contact pressures, and a decrease in friction is caused by a decrease in shear resistance in the zones of contact interaction of protrusions and depressions of surface irregularities. A more significant effect on the decrease in the parameters of adhesion properties is exerted by the POLYTRON^MTC 10% AC components, which cause the formation of secondary lubricant formations with denser structures at the interface of adhesion with metal surfaces and reduced resistance to movement within the formed cohesive bonds between them.

This article discusses influence of titanium compounds on the electrophysical characteristics of materials. Sequence of operations for receive the materials possessing improved radio-technical characteristics is shown. Material characteristics such as permittivity, shrinkage and hardness are described. Higher permittivity (ε) of composites is presented and subsequence and modes fabrication body parts of products. Facts are given that testify that the insertion is 30 % TiO₂ raises permittivity by 1.4 times; interposition BaTiO₃ in the same ratio - 1.7.

The data of mechanical testing of samples manufactured by selective laser melting of powders using the EOSINT M270 unit is systematized. Used powder raw materials of a different chemical composition close to common stainless-steel brands. Melting parameters found to obtain a complex of mechanical properties exceeding the characteristics of monolithic samples.

Spherical granules are one of the preferred forms of biomaterials for bone defects healing. Chemical composition and microstructure of these materials are largely determines their behavior in vivo. Synthesis and properties investigation of polydispersed porous composite granular materials containing several bioactive components are the important task of modern biomedical chemistry. In this work, the microstructure of organomineral granules based on hydroxyapatite, wollastonite, and gelatine, and the products of their calcination were studied. It was found that as a result of removal of the polymer binder from the ceramic particles surface, nanopores were disclosed, and the subsequent crystallites sintering provide the granules shape stability.

Control of the composition after heat treatment is important stage of biomaterials production especially in case of their new versions creation, because many biocompatible synthetic substances are unstable at high temperatures. Interaction between components in multicomponent systems is possible with the formation of new undesirable products. In this work, the process of calcination of composite granules with a variable content of hydroxyapatite and wollastonite and binder polymer (gelatine) was studied. It was found that materials heat treatment leads to a change of their phase composition caused by the apatite decomposition, transition of β-CaSiO₃ to α-form, and calcium silicophosphate formation (in samples where apatite is the main component). Calcined products composition depends on the apatite/wollastonite ratio in the materials.

The effect of the composition of the gas feed mixture on the dissociation rate constant of molecular nitrogen is examined by numerical solving the Boltzmann equation written in a two-term approximation for conditions corresponding to nitride aluminum films deposition. By solving of macroscopic balance equations in volume occupied with plasmas of stationary low-pressure glow discharge in a nitrogen-argon mixture the atomic nitrogen density was determined. It's shown that there is a maximum of atomic nitrogen density at certain stoichiometry of gas feed mixture.

In this article, the microhardness and wear resistance of the high-entropy FeCrNiTiZrAl alloy are studied on model specimens and on turbine blades made of 20Kh13 steel. The alloy was made by mechanical alloying and subsequent annealing in a vacuum furnace. The study showed that the obtained alloy is a high-entropy alloy with a microhardness μ = 740 HV, which is at the level of the microhardness of metallic glasses, but 2-3 times higher than the microhardness of stainless steels. The friction coefficient of the FeCrNiTiZrAl coating is k = 0.06, which is 10 times less than the friction coefficient of the titanium nitride coating (k = 0.65). The wear resistance of the high-entropy FeCrNiTiZrAl coating is much higher than that of stainless steels, and it leads to the fact that the cost of titanium nitride coating on turbine blades is 2 times higher than the cost of FeCrNiTiZrAl coating, that is, the economic effect is obvious.

The structure of Fe-Cr-Co magnetic material, manufactured by selective laser melting (SLM) on RussianSLM FACTORY unit from spherical powder of size less than 80 μm, was studied. The powder was produced by the melt atomization. At different speeds of scanning and laser power, samples were manufactured to study the structure, magnetic and mechanical parameters. By constructing hysteresis loops, data obtained indicating the growth of magnetic characteristics (B_r, H_cb and (BH)_max) in SLM samples in comparison with similar, obtained by foundry technologies.

In the structure of the samples manufactured by the additive method of selective laser melting (SLM) of the Fe-based powder, particles were detected with a minimum size of 0.15 ± 0.05 μm, which were interpreted as germ objects of solidification. The model of additive samples hardening by nanoparticles was proposed, which were formed in the process of desublimations (condensation of metal vapors + crystallization) in the sequence: Metastable state to Segregation to Cluster to Nano-object.

Implementation for the key preliminary distribution scheme in the continuous functions space is proposed. Key materials are formed based on linear differential operator. User characteristics are presented in the form of a harmonic series. We show that this approach allows you to develop a common encryption key. A linear differential operator is formed only from even order derivatives. Odd order derivatives do not affect the encryption key value.

The article reviews the method of measuring the electric field strength by the average value. Its advantages and disadvantages are discovered. Taking into account the identified disadvantages an improved method using a dual sensor and a built-in measuring and computing device, which allows to directly obtain the result of measuring the electric field strength, is proposed. To carry out the improved method of measurement in the devices for measuring the electric field strength, various types of electric induction sensors are considered from the position of minimum error and suitability for the improved method, of which dual sensors are selected. The use of dual sensors and the improved method in the proposed devices for measuring the electric field strength makes it possible to reduce the measurement error to +- (2-5) %. The designed devices for measuring the electric field strength allow obtaining the measurement result in the form of an equivalent of the electric field strength of a point charge.

The research results of the structure influence of single-mode optical fibers of various types on the interaction characteristics of the optic and acoustical modes of lower orders are presented in this work. A method for obtaining of optic and acoustical modes distribution in single-mode optic fibers is considered. The structures of the radial distribution of refractive index profiles for some varieties of single-mode optical fibers with dispersion shift (ITU–T recommendation G.653 and G.653) are presented. The obtained graphs for varieties of optical fibers are presented.

The results of researches of the Mandelstam – Brillouin scattering frequency characteristics in single-mode optical fibers of various types are presented in this paper. A technique for obtaining the spectral characteristics of Mandelstam – Brillouin scattering for predefined acoustic mode distributions in single-mode optical fibers is considered. The procedure for determining the frequency characteristics of the Mandelstam – Brillouin scattering for a given structure of the radial distribution of the optical fiber refractive index is discussed. The Mandelstam – Brillouin scattering frequency characteristics of single-mode optical fibers obtained by mathematical modeling and experimental studies are presented. A comparative analyze of obtained results is carried out.

We present results of the numerical modeling of the relaxation process for the Brownian motion in a bistable potential. Such a process is relevant for the recent nanoscale experiments reported in the literature. The modeling is based on the Langevin equations for the generalized coordinate and its conjugated momentum. First, the calculations are validated for the case of low thermal energy using a comparison with the analytical expressions for the harmonic oscillator. Next, the time evolution of the particle distribution in the bistable potential is analyzed.

One of the necessary, periodically performed by information security (IS) department procedures is to assess the level of compliance of the actual state of any IS measure with the established requirements. These procedures involve a significant amount of manual work, which leads to a waste of time, human, technological resources. In this case it is not always possible to provide a high level of reliability of the results. To reduce costs, increase the degree of reliability and accuracy of the results of assessment of the IS state, and, accordingly, increase the level of confidence in the IS state assessment, it is possible by the use of "small automation" means when performing routine operations of collection, correlation, normalization, analysis of data sets. The most acceptable means of automation is the programming language python, which, in addition to convenience of use, powerful functionality, has an extensive analytical apparatus. This article discusses the use of python as a "small automation" tool for monitoring the relevance of antivirus protection system.

The main element of a complex system that determines its performance and efficiency is its management system. Modern management systems are widely used, including in the management of teams of people united by common goals (organizations, departments, groups of developers, etc.). Information security is no exception - it is not enough to saturate the division responsible for information technology security with personnel, technical systems of information protection, it is necessary to ensure the effectiveness in achieving the goals, which is not possible without an appropriate management system. Information security specialists in organizations of various forms of ownership often face the problem of ensuring effective and efficient protection of information assets. Availability of international and national standards, regulatory documents of regulators does not ensure the achievement of high performance and efficiency indicators. The achievability of these indicators is determined by setting and achieving a number of goals, based on certain strategic principles of information security management system.

The activity of modern organizations, regardless of the form of ownership, is highly risky. There are up to 600 risk factors in total. It is possible to reduce risk levels only after assessing them. The basis of risk assessment is analytical processing of information relating to the sphere of organization's activity. The information to be analyzed is usually accumulated in databases. This information is usually accessed with SQL queries and analyzed with application software. The most rational variant is when the business unit employees are able to select the data from the database and perform their analytics independently. The most convenient, both for sampling information from databases, and for its analysis to use python. However, python, which is an interpreted language, has a disadvantage in terms of information security - access parameters, including user login and password, database connection parameters, are located in the program body in clear form. The option proposed in this article allows you to reduce the risks of privacy violation when accessing the database.

The synthesis of a cylindrical antenna array for ground-based mobile weather monitoring complexes, based on quadrifilar radiators, is considered. The basic mathematical expressions for determining the electrodynamic characteristics of both the radiator from the antenna array and the AA itself are presented. Various phenomenological models of these radiators are considered. The approach to the synthesis of phenomenological models of the radiator and antenna array as a whole is described. The results of such synthesis are given, and the main characteristics and values of DG, CG, SWR, RP for the given type of radiator and AA in the corresponding frequency range are obtained. Techniques for using phenomenological models for operational synthesis of electrodynamic structures such as cylindrical AA and quadrifilar radiator are developed and described in detail. The possibility of applying this approach to the synthesis of this type of structures for radar weather monitoring systems is shown.

The article discusses the features of the implementation of highly sensitive single-coordinate measurements of electric field strength (EFS) by using of jet-drop optical measuring systems (JDOMS). The use of moving monodisperse charged droplets of a jet-drop coherent flow, which acquire a displacement depending on the directions of movement, the level of the EFS and of the droplet charge, is discussed. The issues of implementation of stroboscopic interference measurements of droplet displacements under impulsed illumination of their surfaces, used as curved reflectors, are considered in JDOMS. It is shown that measuring the displacements of the reflected oh drop of the laser beam makes it possible to determine the displacements of the reflecting drop and the value of the EFS at the selected coordinate, respectively. The features of the use of liquids with pigments and additives in the form of nanopowders of highly reflective metals, liquid metals (or their alloys) with a low melting point are considered in the JDOMS.

Paper presents data of the experiments with the advanced model of voice authentication. The main idea of the research is to prove or deny the hypotese that adding generated fake data to the training set of the background model help to increase the probability of detecting fake data of the target announcer. Processing the results of a series of experiments did not confirm the hypothesis.

One of the most important issues in the field of information security has been and remains the issue a reliable user's authentication. A special place among the possible authentication methods today is occupied by behavioural biometrics, which have a high degree of reliability. A keystroke dynamic, as a type of behavioural biometrics, is also capable of providing a high level of protection of information systems in the case of correctly selected characteristics. This article shows that external factors, including the psychophysiological state of a person, can also influence the authentication process by keystroke dynamics. In the paper, the state of the user was assessed in the process of collecting a sample of keystroke dynamics and a conclusion was made about the presence of such an influence.

The paper considers the features of constructing an information model of the human peripheral auditory system in the LabVIEW software environment. A brief description of the adopted information model proposed for implementation in the software environment is given. Detailed explanations are described for each element of the model made in the LabVIEW environment. The main functionality of the user part of the program is presented. The work is, in fact, staged in nature and offers a sequence of further necessary studies of the developed model.

This paper presents the results of experimental studies of 15 design versions of capacitive and induction type microwave antennas. As part of the work on the development of an accelerator ion thruster, 32 radiator designs were studied. The research was carried out in order to select the optimal design of a plasma-generating microwave antenna for installation in the discharge chamber of a prototype ion thruster. The volt-ampere characteristics (VAC) were obtained the microwave generator when working with each design of the radiator in a vacuum chamber. The VAC is obtained in the presence and absence of a high-frequency discharge.

This paper presents the results of an experimental study of the jet thrust of a mixed jet of neutral and ionized nitrogen flowing from the working chamber of an experimental sample of an accelerator ion thruster into a vacuum space. The main method of the study was the aerodynamic double angle method (AMαβ-method). The method of determining low thrust and the design of the stand for the implementation of the AMαβ-method are proposed. The object of research is a prototype of an accelerator two-phase ion thruster with a solid-state microwave plasma generator and a toroidal resonator. The study showed that a 2.5 W microwave generator together with a 2.5 W accelerating potential difference voltage source with a nitrogen consumption of 0.05 -1 mg/s can increase the speed of the working gas by 2.3 times. The jet thrust, according to the test results, was 1-3.6 μN. It is shown that the thrust components (the gas-dynamic component, the ion component of a high-frequency discharge, the ion component of a glow discharge) have different levels depending on the mass flow rate of the gas.

This study focuses on the problem of detecting and locating secret data embedded using the Koch-Zhao steganographic method with discrete embedding. The proposed method of steganalysis is based on discrete cosine transform and enables to control and verify JPEG and MPEG images of stego-payload not exceeding 25%. Mid-frequency components are considered as the components targeted by the Koch-Zhao steganographic method. The proposed method of steganalysis delivers strong detection and locating accuracy and performs in 10-% stego-payload cases with sufficient reliability. Both gray-scale and color images can be verified on being a carrier or not being when using the detecting method proposed in the study.

In this study a new method of steganalysis is presented for detecting and locating a hidden message embedded using LSB replacement as a steganography algorithm. The method is applied for analysing artificial color images of a gradient fill and shows high detection and locating accuracy in low stego-payload of 25 to 10 percentage. The method is based on analysing pixel combinations of an LSB map to classify unique and non-unique pixel combinations and finding the largest rectangle algorithm for, respectively, detecting and locating purposes. To exclude noisy data from further consideration, a pre-processing filter is developed and presented.

This paper considers modern technologies of home telemonitoring related to CPC patients. It presents a new secure intellectual telemedicine service based on remote monitoring of patients' health status, which can be used for CPS patients for their health screenings in remote and hard-to-reach locations, as well as in-house hospitals. It also discusses technologies, problems and prospects of remote telemonitoring systems' development and implementation.