Table of contents

The paper considers the problem of anomaly detection in 3D images of fibre materials. The spatial Stochastic Expectation Maximisation algorithm and Adaptive Weights Clustering are applied to solve this problem. The initial 3D grey scale image was divided into small cubes subject to clustering. For each cube clustering attributes values were calculated: mean local direction and directional entropy. Clustering is conducted according to the given attributes. The proposed methods are tested on the simulated images and on real fibre materials. The spatial Stochastic Expectation Maximization algorithm shows its effectiveness in comparison to Adaptive Weights Clustering.

In this paper, we consider the problem of the study of polycrystalline substances: restoration of a substance atomic structure by full-profile analysis of powder diffraction data. This task is specific since it is not necessary to find very good solutions on average, but it is necessary to find the best one at least sometimes. To solve this problem, it is proposed to use an evolutionary algorithm based on the cooperative island model. The article describes the main stages and features of the algorithm and notes the qualitative advantages of this model in comparison with other methods (including evolutionary). The description of innovations proposed and the results of computational experiments are given. Conclusions from the experimental results are given, and further prospects for improving the efficiency of this method were noted.

This paper considers the development of a mathematical model for spacecraft thermal control fluid circuit systems. The need to take into account the complex mode of heat exchange in a fluid circuit model reflects relevance of the paper. Basic equations of heat exchange model in the circuit are given. A procedure for the numerical solution is described. Obtained calculation results are presented and analyzed. The developed model allows numerical studies to assess an impact on characteristics of the circuit of various design and operating parameters.

The paper describes the developed basics of the preparation technology of solid ceramic coatings on titanium and its alloys. The coatings have been formed by the method of microplasma surface oxidation in electrolytes of different composition. The authors have determined the modes of wear-resistant coating application on titanium alloy, which have significantly decreased coating porosity and made it possible to increase its wear resistance. They have also carried out physical and mechanical, as well as tribological tests of the materials obtained and formed a database of their actual properties. The paper shows that self-lubricating coatings can be operated for a long time at moderate loads and sliding speeds in friction units without using a lubricant. It also describes a newly developed and improved existing equipment to create coatings and study their tribological properties.

Several series of plasticized segmented polyether urethane of linear structure which can be used as the polymer base of thermoplastic materials were synthesized. The possibility of obtaining thermoplastic segmented polyurethane ureas with a softening temperature of 100 ÷120°C when using isophorone diisocyanate as the main element for building polymer chains, and DEHS as a plasticizer was proven. The original method for the purification of aromatic amine 4,4'-methylene-bis(2-chloroaniline) used in the process of synthesizing polyurethane ureas as a chain extender was developed. The polymers obtained have a uniquely low glass transition temperature close to -100°C with a plasticizer concentration of not more than 40%. The strength of these materials is more than 10 MPa at room temperature, and it is more 40 MPa at -70°C.

The paper presents a metallographic investigation of samples of high-speed steel and structural steel with hard alloy coatings applied by electro-spark alloying. Metallographic investigation shows that there is a transition layer between the samples and their coatings where impurities of an electrode alloy material in the structure of the base material can be detected. This indicates that the technological process of the coating is accompanied by diffusion of the materials of the cathode and anode in the transition layer. Microhardness testing shows that the coating can be divided into two layers. The top layer consists of a reinforcing material of the electrode and the base material. It has high hardness, which decreases with the penetration of the coating into the sample because the coating and the base material is mixed. Also, there is the second transition layer, which has hardness lower than the hardness of the base material, i.e., in fact, a secondary temper layer. This layer is a result of high temperature exposure of the process of hardening. Metallographic investigation shows that physical-mechanical properties of the coating can be controlled by varying coating mode.

The research data on the composition, structure and properties of samples manufactured by the selective laser melting of steel powder 09CrNi2MoCu, and plate metal samples of the same grade are provided. In the melted specimens, an atypical structure for this grade was found, and also the excess of some mechanical characteristics over similar ones for specimens from plate metal was found.

The research generates an integral relation of the energy equations for the temperature three-dimensional boundary layer allowing to integrate surfaces of any shape to determine thickness of energy loss. An equation to determine thickness of energy loss is necessary to specify heat transfer law and local heat transfer coefficients within boundary conditions of turbo machinery cavities.

The control of the frequency spectrum state under operating conditions of the satellite networks that include plenty of satellite earth stations is one of the main functions of ground segment of space communication systems. In this case, the control system of the satellite network must measure the parameters of separate network segments or separate earth station if it is necessary. The necessity for selective measurements is relevant in the following cases: the power level, noise level or spurious radiation level of any earth station is significantly higher than the nominal one. The overview of some existing monitoring systems that makes automatic control of the frequency spectrum is presented. The analysis of the problem arisen during the functioning of satellite TDMA networks that involve plenty of earth stations is presented. Based on the analysis, it was concluded that the existing control systems of the satellite networks do not allow measuring high frequency parameters of separate earth stations under TDMA technology. The analysis of the problem of measuring the channels parameters of satellite network functioned by using the TDMA technology is presented. The differences between computations of channel power under "single channel per carrier" technology and the TDMA technology are presented. The authors proposed an automatic control system of high-frequency (HF) parameters of satellite signals, functioning by using the time-division multiple access technology. The block diagram of this system and description of its operation are presented. The conditions for implementing this automatic control system are defined. The time chart and its characteristics were calculated during measurements executing by this automatic control system. The method of match making between the received signals through the satellite segment and the identifiers of earth stations of the satellite network is presented.

Interrelation of operational properties of copper-tin alloy coatings (microhardness, solderability, transient resistance, corrosion resistance), and the modes of stationary and non-stationary electrolysis, allowing to form the coatings with a given set of properties, is revealed. The results of corrosion tests that determine the field of application of the copper-tin alloy are obtained.

A new low temperature ceramic material for 3D printing based on polyaluminosilicate has been synthesized. Some of the synthesis stages are controlled by the parameters set for 3D aerosol printing. The processes of 3D aerosol printing of polyaluminosilicates filled with a highly dispersed filler have been studied. An optimal method for aerosol generation has been chosen that does not affect the supramolecular structure of a polyaluminosilicate binder. Ceramic dielectric topologies with high thermal conductivity and layer thickness in the nanometer range have been obtained by means of 3D aerosol printing of the synthesized material for the first time.

Samples of a composite material based on polypropylene matrix and carbon fillers (carbon black and carbon nanofibers) were obtained. It was experimentally shown that the dependences of the electrical conductivity on the filler mass fraction have a threshold nature/When the mass fraction of the filler is higher than the threshold the values of the electrical conductivity increases by more than 8-10 orders. Determination of the electrical conductivity value near the percolation threshold is difficult. In the article the simulation method was proposed which considers the presence of a dielectric layer between the filler particles, presented a method for its evaluation: the percolation curve near the percolation threshold was described. A fairly good agreement between the experimental and theoretical values of conductivity for various geometries and types of fillers is shown in this work.

The problem of uncertainty factor management in the description of mechanical stress nearby hatchways of multilateral form with rounded corners of fuzzy curvature in stretch thin plate is considered. Numerical and analytic methodology based on heuristical principle application of extension to transition to fuzzy set arguments in special analytical representations for estimated factors of stress concentration is proposed. Algorithm of fuzzy interval parameter spread of curve in corner points is described. Usage of proposed methodology in theoretical and applied researches on integrity problems of multiply connected thin-walled structure elements is characterized.

Based on the analysis of modern experimental data dedicated to anodic behaviour of silver in solutions containing halide anions, an equation establishing the dependence of the peak-start potential of silver passivation on the potential scan rate, ion halide concentration, and solubility product of silver halide, was obtained. It follows from the proposed equation that the smaller the solubility product value and the potential scan rate are, and the greater the concentration of anion halides is, the anode passivation occurs at a lower potential value. The equation agrees with the experimental data presented in the modern literature rather well. The results can be used in studies aimed at finding the optimal modes of anodic treatment of metals, the development of measures to increase the corrosion resistance of materials, as well as for the quantitative analysis of chlorides, bromides and iodides in solution, including their co-occurrence.

The paper contains an analysis of the task of establishing quantitative information reflecting the properties of the observed object. The authors of the article showed that in order to operate, both controls instruments and measuring instruments, it is necessary to form a "Euclidean measure" for the property of the object at the current time. The article describes an independent method for estimating the uncertainty of the state of an object by calculating the entropy of its observed properties. In particular, it is shown that the entropy potential is proportional to the measure of Euclidean space. A description is given of the method for determining the shape of an approximating function for sampling results based on a comparison of the difference between Euclidean measures and measures of the information space formed for entropy potential.

Aerospace systems occupy an important place in the information, telecommunication, defense infrastructure of the country. These systems have strict requirements for safety and reliability. The study of dependability allows you to find the distribution of device operating time to failure. This is especially important for the non-recoverable onboard equipment of aerospace systems. Practice shows that even 5 years of active life is difficult to achieve, and for profitability it is required to ensure 2-3 times more. For such a period of operation, the radio transmission devices of spacecraft are exposed to prolonged exposure to ionizing radiation of natural origin. This leads to accelerated aging of materials, degradation of parameters of the electronic component base and single effects of failures and failures in semiconductor devices and integrated circuits, which must be taken into account when analyzing the reliability of newly developed and modernized devices.

Composite materials which include components (binding and fillers) that provide technological and operational characteristics were investigated. As a fillers AlN, Al(OH)₃, SiO₂, CaSi0₃ powders are used. Binder – dimethylsiloxane rubber SKTN A + PMS silicone oil in 4:1 proportion. Studied composite materials are designed for dielectric coatings materials creation, which have a high thermal conductivity and do not support combustion (through the use of fillers with flame retardant properties). The results of experimental studies of the mechanical characteristics of composite materials based on siloxane binder and fillers in the form of fine powders AlN, Al(OH)₃, SiO₂, CaSi0₃ are presented. The values of strength, coefficient of elasticity, relative elongation in tensile tests, modulus of elasticity in compression tests, Shore hardness are measured.

The fuel and energy complex is the basis for the development of all sectors of the Russian economy. Its most important element is trunk pipeline system for the transport of gas, oil and their products. The main gas pipelines with cathodic protection, are exposed to the impact of ground electrolytes and tensile stresses. As a result, corrosion cracks may appear on the pipe surface. One of the most dangerous types of destruction of gas pipelines is stress-crack corrosion (SCC) of the outside cathode-protected metal surface of the pipes. There are no efficient methods for SCC control at present (the only method for SCC control is application of anti-corrosive insulation). One of the methods for detection of stress-crack corrosion is the stress test, however, its application is justified only for single cracks. There is a system of cracks in practice. Analysis of the focal zone of the collapsed gas pipeline with multiple cracks was carried out in this research. Studies were conducted on a sample of X70 steel made in Japan, selected from the focal zone of destruction of the West Siberia gas pipeline. The sample has 4 cracks typical for SCC crack. A metallographic analysis of the X70 steel and the calculation of the stress-strain condition of the metal were carried out. On the basis of the obtained results, it is proved that tested cracks have a corrosion-mechanical origin typical for stress-crack corrosion.

We have studied the time evolution of the laser-induced fluorescence spectra of oil pollution on the terrestrial surface at a fluorescence excitation wavelength of 355 nm. The paper presents a block-diagram of the experimental laboratory setup and data processing results of the laser-induced fluorescence spectra for the oil-polluted soil and sand and conducts a comparative analysis of the fluorescence spectra evolution of pollution due to spilling crude oil and heavy and light petroleum products.

A composite material based on polyaluminosilicate and highly dispersed filler powders of AlN and Al2O3 has been synthesized by means of the sol-gel synthesis. The pH effect on the Zeta potential of highly dispersed filler powders of AlN and Al2O3 has been investigated. The effect of the Zeta potential of filler powders on the sol polyaluminosilicate stability has been studied. Ceramic coatings for printed circuit boards have been obtained by 3D aerosol printing.

The paper presents the results of studies on the availability and resistance to brittle fracture of perspective austenitic chromium-nickel-manganese cryogenic steels, depending on the concentration and ratio of the nitrogen and vanadium content. The optimum content of these elements in deformed steels determined, the results of the studies and recommendations on the doping system are confirmed by the results of full-scale tests of low-temperature equipment under internal pressure in liquid nitrogen.

The article presents the current trends in the recomposed work stand and the terminology used. Technical solutions were considered in order to optimize the use of this system type. Intermodular element of locating and fixing - multi-tiered was proposed. This device contains automatic plug-in units, layout - multi-tiered. Tiered layout does not always meet the requirements of the technical process. Industrial robot for automatic replacement of nodes was proposed.

The most important element of fuel and energy complex is the system of the main pipelines for transport of gas, oil and products of their processing. On a surface of the main pipes in the presence of cathode protection there can be corrosion cracks. It is connected with simultaneous influence of two factors - soil electrolytes and the stretching tension. One of the most dangerous types of destruction of main gas pipelines is stress-crack corrosion (SCC). Defects on an outer surface of a pipe are shown in the form of single cracks or their system focused generally along the forming pipe. In work studying of the multiple cracks formed on the main gas pipeline under the exfoliated isolation is presented. Researches were conducted on a sample of X70 steel of the Japanese production which is selected from a focal zone of destruction of the main gas pipeline. On a sample there were cracks, characteristic of corrosion cracking. For the proof that cracks had corrosion and mechanical origin electronic and microscopic researches of dislocation structure of metal near crack top were conducted by means of a method thin foils and also the diffraction pattern of the site with a crack is studied.

The paper deals with a mathematical model of thermal state of a porous body which is in form of a rectangular parallelepiped. The internal heat generation and the heat exchange between the surfaces of the porous body and surrounding medium were taken into account in the model developing process. In order to solve the problem, there was developed a modification of the finite-difference method based on the method of lines. Also, using the least squares method, there was proposed a sinusoidal formula for describing the annual variation of ambient temperature.

The paper discusses the methods for measuring the flight altitude of aircraft and the design features of pulsed radio altimeters. The results of model experiments in measuring the height by a pulsed radio altimeter are given.

An integral relation of the temperature spatial boundary layer energy equation, which allows integration over the surface of any shape to determine the thickness of the energy loss, was obtained. The equations for determining the energy loss of the temperature spatial boundary layer thickness are necessary to determine the local heat transfer coefficients for the characteristic cases of flow, taking heat exchange into account. The corresponding flows in the power unit cavities are considered. Turbulent flows of a gaseous flow were considered. Calculations for local heat transfer coefficients are defined. The local heat transfer coefficient for a rectilinear flow, a rotational flow according to the law of a solid, and a rotational flow according to the law of a free vortex were determined. Calculations for local heat transfer coefficients are defined as Stanton Criteria.

Polyaluminosilicates with different chemical structures have been synthesized. They have been experimentally studied and a priori estimated. Dielectric ceramic layers have been obtained by means of 3D aerosol printing and studied with the use of synthesized polyaluminosilicates and highly dispersed powder of Al₂O₃ ceramic filler.

The paper considers the current state of the metallurgical industry including the issues of automating the production of metallurgical silicon in ore-smelting furnaces. The main problem areas are revealed in the production cycle of obtaining metallurgical silicon, such as the lack of operational information on the moisture and ash content of the reducing agent, a static error in the testimony of furnace ammeters at different levels of the furnace transformer, the absence of a system of bypass electrodes under load. As a recommendation, the introduction of a three-tier control system, the modernization of the weighing and dosing system for charge materials, and the system for the automatic transfer of electrodes without shutting down the furnace are proposed.

The article deals with the methods and means of using the inter-satellite measurements on the laser communication lines for high-precision temporary support of the GLONASS system spacecrafts. There is given the justification of the principles of measuring and exchange information among the spacecrafts via the laser navigation and communication lines for mutual synchronization of the on-board time scales of the GLONASS system spacecrafts.

The mechanical behaviour of an aluminium welded liner in a cylindrical metal composite vessel of high pressure made by winding on a linear carbon-filled plastic tape with tension is investigated. The resulting pressure of the wound composite shell on the welded liner is simulated by cooling the shell. It is believed that the weld is obtained by friction welding and has characteristics that are reduced in relation to the base material of the liner. The problem is solved in a geometrically and physically nonlinear formulation using a 3D solid element model, taking into account technological deviations and in real (current) time. The calculations were performed in the LS-DYNA software package in a dynamic formulation. It is shown that liner delamination from the sheath starts from the side of the circumferential weld in the area of technological deviations.

The molecular dynamics method is used to consider the effect of energy transport in an A₃B stoichiometry crystal, using Pt₃Al as an example, which consists in the transfer of energy at frequencies outside the phonon spectrum of the crystal. This effect is called the effect of nonlinear supratransmission. The model was a bulk face-centered cubic crystal, the atoms of which interacted through a multi-particle potential, obtained by the immersed atom method. Different forms of oscillation of the region of external influence are considered. The possibility of transporting energy from the crystal surface into the depths by means of excitation of quasi-breathers near the impact area and their subsequent destruction in a crystal and dissipation of energy, stored on them, is shown. The quasi-breathers most intensely occurred near the impact region with a sinusoidal waveform. The results obtained indicate that the contribution of quasi-breathers to the energy transfer through the crystal, increases with increasing exposure amplitude. The minimum amplitude of the external influence, at which this effect was observed, is established. The results of the study can be useful in creating materials with predetermined properties, through various intensive external influences.

The heterogeneous structure of composites is linked to their wear resistance under abrasive wear conditions. It was found that the DP content in the CEC corresponding to the highest strength of the wear-resistant material depends on the ratio of the strength properties of the matrix and the filler. It can be calculated using the continuum theory for the case of two-sided congestion of elliptical dislocations.

On the basis of available experimental data of the state diagram Li-Ga system, thermodynamic simulation of liquidus in the system Li-Ga has been carried out with using of the model of subregular solutions. From the results of calculations energy parameters of mixture of system components in a melt have been determined and the temperature dependences of constants of melting of chemical compounds in the system have been found out. The developed calculated liquidus line of the system corresponds to the available experimental data of the state diagram. The results of the research allow determining the dependence of activities of components in melt on atomic per cent and can be used while growing monocrystals of gallium nitride in lithium flux.

A method for determining the direction to the source of interference without the use of additional antennas is proposed. It provides interference suppression in the direction of the side lobes of the radiation pattern due to additional synthesis of the antenna pattern for the central beams without complicating the calculation algorithm and without using additional antennas.

We propose a recursive algorithm for dividing a presumably mixed production batch of semiconductor devices into homogeneous groups (clusters) with the use of data of non-destructive testing, based on the maximization of the silhouette criterion in the sequential solving of the k-Means clustering problems. Based on the silhouette criterion, we formulate the concept of homogeneity of a production batch. The application of the developed algorithm to the problem of formation of homogeneous production batches of integrated circuits for space industry is illustrated with a computational example.

The structure and properties of welded joints of reinforced steel micro-alloyed with vanadium were investigated. The reasons for the formation of cold cracks are given. It has been established that welding at negative ambient temperature in the near-weld zone of rebar class A500C forms quenching structures with a hardness of up to 470 HV. Preheating of the rods by gas welding leads to a decrease in the temporary tensile strength. The technology of mechanized welding in carbon monoxide is proposed. It has been established that in multilayer welding in a reducing atmosphere, the carbon equivalent value of the weld metal increases. The hardness of the heat-affected zone decreases to 200... 260 HV. Mechanical properties of welded joints made in carbon monoxide environment comply with the requirements of regulatory documents.

The purpose of research is to provide a competitive alternative to aluminum silicon alloys used in automotive applications. This alternate can be created by developing composites of Al-5%Cu alloy reinforced with B4C particulates with a low coefficient of thermal expansion. Stir casting can be used to produce Al-5%Cu alloys containing different ratios of B4C. The squeeze casting technique decreased the porosity of the final material. The composites exhibited a fairly uniform particle distribution throughout the alloy matrix.

The paper considers possible application of modern prognostication techniques as an element of a quality control system. Applied mathematical tools are the artificial indistinct neural networks with the inverse distribution of a TSK type architecture error. The analysis is made of the factors influencing the ferroconcrete durability. The selected input characteristics are: the sand fineness module, the number of of a lamellar and needle-shaped grains in crushed stone, cement volume weight, of a cement stone strength. The output parameter is the arithmetical mean value of the destroying force by the results of three experiments. The MS Access database was formed on the basis of the laboratory logbooks of the production input control. Two groups of tuples are formed: for training of indistinct neural network and for adequacy tests of the trained network. Mathematical model showed the efficiency of testing. The average error value was 9.6 kg/cm² or 2%.

The composition of electrochemical coatings of nickel-zirconium dioxide, the peculiarities of their morphology were investigated. It was shown that depending on the dispersion and the method of preparation (plasma-chemical method and deposition method) of the dispersed phase, the content of inclusions in coatings varies from 0.2 to 1%, in the case of the plasma-chemical method and from 0.3 to 2%, in the case of particles obtained by the deposition method. Nickel-zirconium coatings are characterized by increased microhardness, corrosion resistance, and wear resistance compared to control precipitates by 1.4; 2.4 and 1.2 times respectively.

An integrated model of phase transformations is proposed, which unites the model of changes in the temperature fields of the workpiece during welding and subsequent cooling, as well as a simulation model of phase transformations that occur during cooling of the steel. The developed method allows predicting the amount of residual δ-ferrite in the structure of the weld of austenitic stainless steel, which is necessary to justify the welding conditions.

A model of mass transfer of two-component gas through an absorbing porous body was developed. The mathematical model is a problem of Stefan problem type. Analytical solutions of the model in the quasi-stationary regime were obtained. For the transfer of nitrogen-oxygen mixture by titanium porous adsorbent, the dependences of the gas penetration depth and the mass absorbed by the adsorbent on the temperature, the pressure of the gas mixture and the diameter of the porous material particles were calculated. It was found that the size of the nitrogen absorption area was several times smaller than the size of the oxygen absorption area. Also, the mass of the absorbed nitrogen was half the mass of the absorbed oxygen. This is due to the remoteness of the nitrogen absorption area from the outer surface of the titanium adsorbent.

This article represents the method of creation and verification of a simulation model consisting of graphical structure duplicating the elements of spacecraft onboard equipment and the knowledge base describing the methods of its function. The authors have developed software tools for model building and verification with the help of visual components converting formal description of the model and the knowledge base into interactive graphical images of infographics. The method can be used at any stage of onboard equipment designing, however it is most efficient at the initial stages.

The paper deals with the task of determining the actual traffic routes based on the data of the global satellite navigation system during the dispatching control of road transport. The actual route through the transport network is an ordered set of traffic control points passed. The fixation of control points of the route in the processing of satellite navigation data is carried out by means of two radii: the radius of detection and the radius of positioning. The paper proposes a method for processing satellite navigation data, consisting of two stages: first, pre-processing and, second, calculating the parameters of the system states defined by the dispatch control tasks. The state of the system controlled by the traffic dispatcher system is described.

The expediency of polymer-metal coatings reinforced with polyepoxides use for increasing the wear resistance of machine parts is described. The composition and structure of composite coatings providing the highest wear resistance are presented in an optimized way.

Centrifugally cast pipes from heat-resistant steels and alloys are widely used in many branches of engineering. These are radiation pipes in thermal furnaces with a protective atmosphere, bottom rollers in continuous thermal and heating furnaces of metallurgical plants, rollers in continuous annealing units, etc.

The question of the possibility of increasing the operating parameters of the process of high-temperature conversion of natural gas in ammonia and methanol units is very important, because increasing the temperature and pressure not only improves the performance of the plants, but also reduces the cost of the product and allows obtaining higher purity hydrogen. In connection with the above, specialists are making efforts to improve the compositions used in steels of the type H25N35C2 by means of their additional doping.

Fatigue damage of the surface layers of metal is a characteristic cause of failure of rolling bearings, gears and a number of other machine parts operating under cyclically repeated contact loads. Resistivity to the development of contact damage of steels obtained by hot forging porous blanks is determined by the presence of cohesive bonds between the particles of the base powder, as well as by the presence of non-metallic inclusions and grain size. The possibility of increasing the contact endurance of hot-deformed powder steels due to micro-doping with calcium has been studied. Iron powders with various content of impurities, as well as atomized powder of low-alloyed chromium-molybdenum steel were used as the basis for preparation of the blends. Calcium was doped as calcium carbonate. Mixing was performed in a planetary centrifugal mill. Samples for mechanical testing were obtained by hot forging porous blanks. After hot forging the samples were carburized to compensate for the loss of carbon in the surface layer. It has been established that doping calcium microadditives is favourable for increasing the energy content of damage under the conditions of exposure to contact-fatigue and bending loads. This is due to a decrease in the size of austenite grains at the expense of inhibition of their growth during the adsorption of calcium at the grain boundaries. Microalloying with calcium changes the localization of seats of contact fatigue damage. In samples-witnesses without microadditives of calcium cracks originate near non-metallic inclusions of sharp-angled shape in the near-surface zone. In microalloyed specimens the cracks are located in the subsurface layer in the area of Hertz maximum shear stresses.

The paper studies the monopulse lidar method capabilities for sounding the reflection coefficient of the earth surface. The mathematical modelling shows that the monopulse lidar method allows us to reconstruct spatial distribution of the reflection coefficient under measurement noise in a good-sized angular coverage of lidar. The most efficient for reconstruction of the reflection coefficients based on the measurement data (in terms of both the minimum errors and the computation time) are the hybrid particle swarm algorithm and simulated annealing and the ant colony algorithm. The monopulse lidar monitoring method using the hybrid particle swarm algorithm and simulated annealing and the ant colony algorithm allows (with an error of estimating expansion coefficients from units of per cent to 10 - 40% under measurement noise of 3%) adequate reconstruction of spatial distribution of the reflection coefficient on the earth surface under conditions of strongly and nonlinearly changeable reflection coefficient.

The article deals with topical issues of spacecraft external design for the global navigation satellite system (GLONASS). The development and analysis of data processing algorithms are considered a part of the external design phase. Data for processing algorithms was obtained from real orbital grouping spacecraft. Mathematical modelling was performed based on real data to analyse navigation signals propagation conditions from GLONASS satellites. Implementation of mathematical modelling approach included such aspects as finding the optimal antenna pattern and filtering radio frequency signals. Theoretically optimal antenna directivity patterns were implemented taking into account available data about satellite orbital parameters. Bessel, Butterworth, Chebyshev and elliptic filters were used as standard filtering methods. Modified low-pass filtering algorithm was considered as an improved filtering algorithm. Application of the modified filtering method allowed to reduce geometric dilution of precision value in the consumer positioning case. Obtained results are applicable to design possible options for improving the existing GLONASS orbital group.

The article deals with the formulation of austenitic heat-resistant steels and its influence on the structural heterogeneity of reaction pipes based on them for reforming furnaces manufactured by centrifugal casting. Using highly informative methods, the formation of two intermetallide phases in the austenitic matrix, performing the function of metal hardening at high temperatures, is shown. Their composition was determined, the heterogeneity of the distribution along the length of the reaction tube and, as a result, the variation of the values of mechanical parameters were shown.

A calculation method is proposed that combines two existing methods for calculating the strength of reinforced concrete beams. The author of the article considers the possibility of presenting the work of a reinforced concrete beam in the form of an arch with a curvilinear shape with a puff, which is a statically definable system. The operation of a reinforced concrete beam with a relative span of a slice from 1 to 3 is modeled as an arched system with a horizontal stretched reinforcing belt and a compressed concrete strip of curvilinear shape. The purpose of the tightening in a beam with an average relative cut span is to cancel the bending moment inherent in a simple beam. Thus, this model (arch with tightening) most fully reflects the work of reinforced concrete beams with an average relative cut span compared to the model adopted in regulatory documents.

The study of the fragmentation parameters of non-metal objects, usually oxide-silicate, when colliding with metal barriers at various speeds is an important aspect of ensuring and assessing the reliability of the structure in aviation and space engineering, as they help simulate collision situations with striking objects in the air and space. With such an assessment, the size and number of fracture fragments are determined, as well as their speed and direction of movement at the moment of impact and after it. The problem of estimating the physical parameters of fracture fragments, such as size and weight, has been solved quite well, however, these methods are quite laborious. Evaluation of the speed and direction of movement of the fracture fragments is carried out, as a rule, when analysing the video recording of an experiment. The quality and information content of such an assessment depends on the quality of the video, shooting parameters and processing method. The paper proposes to use the image analysis implemented by using open source software ImageJ-Fiji for video processing and for estimating the parameters of fracture fragments. The paper discusses the experimental data on the impact of a spherical object of an oxide-silicate composition with a diameter of 23 mm with a static barrier - a sheet of titanium alloy 2 mm thick at a speed of 230 m/s. It is shown that using image analysis and statistical data processing, parameters such as the size and number of fracture fragments, the initial and final velocities of objects moving, as well as the direction of their movement can be set.

Authors propose parallel greedy heuristic k-means clustering algorithms for implementation on the graphical processing units (GPU) for solving large-scale problems. The computational experiments illustrate high performance of the GPUs in comparison with running the greedy heuristic algorithms on a central processor unit which is especially significant in the case of big datasets and bug numbers of clusters. The efficiency of the greedy heuristic algorithms in comparison with the standard k-means algorithm remains.

The weldability range of a VT1-0 + AMg6 bimetal without the traditional use of an intermediate layer of AD1 is determined. The phase composition of the melts on the interlayer boundary obtained by explosion welding of a titanium and an aluminum alloy at different values of the kinetic energy expended on the plastic deformation of the surface layers of metal was investigated. In the vortex zones, areas of melted metal with a hardness of 10-14 GPa were measured.

Since a satellite orbit is quite smooth, polynomial techniques can be widely used for the interpolation of satellite positions in real-time applications. The paper is devoted to the comparison of different approaches to the polynomial interpolation of the trajectory of a satellite using available data. All approaches have been examined for test and actual data.

The study is devoted to the urgent question of forecasting the development of defects in the form of cracks in a two-layer elastic material, which affect its strength and durability. The results will allow us to simulate the occurrence and behaviour of the defect from the insufficient strength of the material, as well as to formulate the optimal operating conditions for the two-layer material. Given analytical expressions will let to see the effect of various parameters of the initial state on the development of a defect in the form of a crack of a longitudinal fracture.

In this work, ab initio studies of a novel two-dimensional diamond-like nanostructure consisting of two polymerized graphenes are carried out. This nanostructure called binary graphane has a two-dimensional hexagonal lattice with the parameter a = 0.2737 nm. The surface density, cohesive energy and indirect band gap of binary graphane are 0.123 μg/cm², 6.64 eV/atom and 2.83 eV, respectively. It is also established that this layer must be stable up to 200 K.

In this work the possibility of using TiO₂ coating as a barrier between carbon fiber and an aluminum matrix in a Cf/Al composite was studied. Specimens of a composite with a matrix of Al-6Mg alloy were obtained by the method of liquid-phase infiltration under pressure. As a reinforcing component was used continuous uncoated and titanium dioxide coated carbon fibers. TiO₂ coating on carbon fiber preform were prepared by sol–gel method. The protective properties of the coating and the mechanical properties of the composite at three-point bending were evaluated. Microstructural and fractographic analyzes were performed. It was established that the barrier coating made it possible to increase the strength of the composite more than 2.5 times from 250 MPa to 660 MPa.

As a result of a theoretical analysis of the possible structure of polymorphic varieties of compounds obtained from the fluorination of L_4-8 graphene, the possibility of existence of 6 main structural varieties of CF-L_4-8 layers is established (T1-T6 structural types). Ab initio calculations of these layers were performed by the density functional theory method using the generalized gradient approximation. As a result of the calculations, it was established that only five polytypes have a stable structure except for the T3 type layer. The crystal lattices of CF-L4-8 compounds are tetragonal for the T1 - T5 types, and for the T6 type crystal lattice is orthorhombic. The sublimation energies of CF-L_4-8 polymorphs of fluorographene vary in the range of 13.36 to 14.09 eV/(CF), which is slightly less than the calculated value of this parameter (14.32 eV/(CF)) for experimentally synthesized CF-L₆ fluorographene of T1-type. The maximum band gap, equal to 4.96 eV, is observed for the T2 type layer, and the minimum value (3.05 eV) corresponds to the fluorographene layer of the T3 type.

Approaches to the problem of the formation of microchannels of arbitrary shape on optical glass substrates and other fragile materials without microdefects (cracks and chips) both on the surface of the substrate and inside the substrates are considered. Different approaches to the formation of laser beam trajectories within microchannels are considered. It was found that the raster scanning method improves the performance of the laser micromachining process and provides the ability to write structures of any length without longitudinal cracks with the energy characteristics of the laser spot in the focus much higher than those in the vector scanning method.

The calculation of the structure and electronic characteristics of polymorphic varieties of boron nitride with a two-dimensional structure was performed by the methods of the density functional theory. The possibility of stable existence of three main structural varieties is established: BN-L₆, BN-L_4-8 and BN-L_4-6-12. The sublimation energies of these polymorphs of boron nitride are 18.14, 17.36, and 17.14 eV/(BN), respectively. The BN-L₆ layer has a structure similar to that of experimentally synthesized hexagonal boron nitride. The layers BN-L_4-8 and BN-L_4-6-12 are new polymorphic varieties of boron nitride. The band gap of these layers is about 3.9 eV. This value is less than the calculated value of 4.69 eV for the band gap of the BN-L₆ layer.

The paper investigated the technical specification as the main document describing the major functions performed by the aircraft. The functional appearance of the on-board equipment complex is revealed in the first approximation. A range of tasks related only to solving problems of navigation and aircraft control is highlighted. The possibility of decomposition of functions depending on their degree of complexity is presented. The process of selecting existing systems to perform the required functions is investigated. The possibility of automating the process of designing a functional appearance based on existing systems is described. The system selection process has been formalized to enable the use of computer-aided design systems in order to shorten the design of the functional appearance of the upper level and minimize the functional inadequacy or redundancy of the complex.

The paper presents the results of experimental studies of the solid particles erosion resistance of titanium Ti-6Al-4V alloy samples, made using additive technologies with different types of protective coatings based on chromium and carbide chromium (Cr-CrC) and DLC (Diamond-Like-Carbon). By means of complex of laboratory equipment, the characteristics of the formed types of coatings were determined, such as thickness, composition, microhardness. Studies of the resistance to impact of solid particles were carried out on an experimental test stand for the study of solid particles erosion of materials and protective coatings at an air-abrasive flow rate of 170 m/s, a flow angle of attack of 30 ° and a sample temperature of 25 °C. It has been established that an ion-plasma coating based on Cr-CrC, 7–9 μm thick, increases the abrasion resistance of titanium alloy samples made using additive technologies not less than 1.5 times.

Resonance theory of usual oscillatory circuit is expanded in case of time-variable circuit of general aspect, in which all elements change with time in accordance with continuous periodical functions of the same period. There exists potential possibility of dissemination it to nonlinear circuit by means of principle of linear introduction.

To improve the efficiency of the joints formation, a new method of pressing in the longitudinal direction is proposed. This paper presents a predictive model for the pressing force depending on the state of the wood and the parameters of the pressed mortise. The most significant factors are the width of the mortise and the moisture content of the wood. Interestingly, the depth of the mortise formation is a less significant factor, which means that the pressing technology will allow to form a long glue line and accordingly high joint strength due to sufficient profile length. In the test range of factors, the best results in terms of energy costs are shown by a minimum mortise width of 4 mm. Further research should be devoted to the study of the formation of small width mortises (4 mm or less) and the investigation of their quality.

The thermal stability of the Cr20Ni80 / (Ni₂A₁₃ + CrAl₇) layered coating on Ml copper substrate was studied. It is found, that the sequence of phase transformations in layered coating during the heat treatment in temperature range of 700-1000 °C is Ni₂Al₃ + CrAl₇ → Ni₂Al₃(Cr) + NiAl(Cr) → NiAl(Cr). It is shown, that an increase in temperature and duration of thermal effect leads to the alignment of Al, Ni and Cr content over the coating thickness due to the diffusion redistribution of elements and to the formation of a secondary reaction zone with a high chromium content.

The paper presents the results of erosion tests and metallographic studies of titanium alloy samples manufactured by using 3D printing and traditional technological methods without coatings and with various types of ion-plasma coatings. As a result of the tests, the kinetic curves of erosion wear of the studied alloys and coatings were obtained, showing that the best type among those considered is a DLC (Diamond Like Carbon) coating, which increases the relative erosion resistance of uncoated samples in incubation period duration of the water droplet erosion process by not less than in 1.8 times.

Increasing the reliability of equipment used for production, transportation, storage and utilization of hydrogen is directly related to solving the problem of hydrogen embrittlement of metals. Without a fundamental physical theory, it is necessary to predict the bearing capacity of metal structures on the basis of obtained experimental data on the effect which hydrogen have on metal properties. This paper presents a solution (based on the method of discrete orthogonalization proposed by S.K. Godunov) of a physically-nonlinear problem of stress distribution in a titanium shell. Since hydrogen, most notably, reduces plastic properties of metals utilized in structural elements, a critical point was determined where the intensity of shear deformation is maximal. It was found how the intensity changes at a critical point of a shell if the pressure within the device rises to an emergency level. Such a rise of the pressure in the shell could lead to appearance of plastic deformation regions, and hydrogen exposure is manifested in reduced breaking stress and changed fracture pattern.

The task is to analyse the temperature distribution in the material under ultrashort laser irradiation. The mathematical model is built on the basis of a two-temperature model describing transition phenomena in a nonequilibrium electron gas and lattice with an ultrashort laser effect on the material. The vaporized body is considered as a thin plate and the problem is formulated as a system of one-dimensional boundary-value problems of the heat equation written for the electron and lattice components. The initial problem is reduced to solving a system of singularly perturbed boundary problems of the heat equation with nonlinear boundary conditions on moving boundaries, an approximate solution of which is obtained in the form of an asymptotic expansion of the solution in the Poincaré sense in powers of small parameters.

The diffusion interaction at the interlayer boundary of the Cr15Al5 alloy during aluminizing by hot-dip in a molten bath of AK12M2 silumin is investigated. It is shown that subsequent heat treatment at 1000 °C leads to the formation on the surface of the Cr15Al5 alloy a coating of variable composition based on iron aluminides FeAl(Cr, Si) / Fe₃Al(Cr, Si) / Fe(Al, Cr, Si). Grain growth in the Cr15Al5 alloy and a decrease in the density of carbide inclusions with their segregation along the grain boundaries ensures a decrease in its microhardness compared to as-received condition from 2.1 to 1.6 GPa.

The structure and electronic characteristics of new polymorphic varieties of graphyne, obtained on the basis of the L_4-8 graphene layer, are investigated by the method of the density functional theory in the generalized gradient approximation. Theoretically, seven types of graphite were built: α-L_4-8-, β1-L_4-8-, β2-L_4-8-, β2-L_4-8-, γ1-L_4-8-, γ2-L_4-8-, and γ3-L_4-8-graphyne. However, as a result of geometric optimization, the structure of two graphyne layers (γ2-L_4-8-, and γ3-L_4-8-graphyne) was transformed into a graphene structure. The sublimation energy of the remaining graphite layers is in the range from 6.63 to 6.79 eV per atom. This energy is lower than the sublimation energy of graphene layers, however, it is in the range of sublimation energies characteristic of carbon materials that are stable under normal conditions. The band gap for the graphyne layers is zero or tending to zero, therefore the properties of the layers must be metallic.

In this article low-alloy structural steel 13Mn6 is welded by hybrid laser-arc welding. To increase the homogeneity of the weld metal during welding, an austenitic filler wire was used. To find out the working characteristics of the joint obtained by the HLAW method, metallographic studies were carried out, the microhardness of the welded joint was measured, tests for static tensile strength and static bending were carried out, and fatigue properties of the joint were also investigated. HLAW with the use of austenitic wire can positively influence the properties of the welded joint. In addition, when welding parameters vary, there is a possibility of penetration of the filler material to the entire depth of penetration, as well as to some partial value of its penetration. The article considers the principal possibility of joining heterogeneous materials on the example of 13Mn6 and 308SS steels.

The article deals with the problem systems automated testing of microcontrollers. A system architecture proposed for fault diagnosis and determining the consequences of device failures. Highlighted separately intermittent failure. The issue of integrating software and hardware failure simulation tools into the testing architecture investigated. Model studies of the testing system performed and conducted diagnostics of simulated faults. The efficiency technology of automated testing confirmed with simulation known failures types (injection) for the components of the performed microcontroller device is proposed.

An active geological study of promising areas for oil and gas is being conducted in areas where geological signs of associated hydrocarbon manifestations are detected. The development of deposits contributes to a developed system of cracks in the surrounding rocks. Fluid supply to fractured reservoirs occurs through the channels of deep faults. Prolonged winter freezing of rocks inhibits the release of gases into the Earth's atmosphere. The accumulation of hydrocarbon gases in the near-surface cavities creates risks of gas emissions, fires and explosions. Prediction and rapid diagnosis of gas emissions is based on planetary observations from satellites of ozone concentration in the atmosphere. V.L. Syvorotkin experimentally showed a causal relationship between hydrogen degassing and the formation of "Ozone Holes". Satellite measurements of ozone concentrations in the atmosphere allow daily monitoring of hydrogen degassing sites from the Earth's surface. The state of the soil surface in the areas of deep degassing is determined by secondary features. These are griffins, soil emissions, ring-shaped structures of gray soil (falling fertility), and hummocks of specific morphology. Such hummocks are formed as a result of the vital activity of "Hydrogen bacteria" and are markers of gas emission on the ground. In combination, methane with hydrogen is capable of detonation at concentrations ranging from 1%. The danger increases in the presence of iron-containing minerals that can catalyze the oxidation reaction. Preventive measures are proposed to prevent the sudden release of flammable gases: by drilling a network of control waste wells with a depth of 100 to 200 meters. Such wells are similar to ventilation wells in areas of coal mining.

Based on the analysis of trends in the development of aviation equipment for various purposes, the expansion of the use in its bearing structures of polymer composite materials, reinforced with carbon fibres with a combined structure containing distributed in the volume of metal honeycomb fillers is shown. This increases the anisotropy of the physical and mechanical properties of such structures of different chemical composition and properties of materials, which makes it difficult to manoeuvre the aircraft due to the different stability of metals and composites to multidirectional dynamic bending and shear loads. It is stated that the problem of increasing the strength characteristics of PCM can be solved by their quasi-structuring in the microwave electromagnetic field, but the influence of this factor on complex structures containing metal regular elements needs further study. Experimental studies of the effect of short-term exposure to microwave electromagnetic field with a frequency of 2450 MHz on the modulus of material elasticity, which is a structure of two plates of carbon fibre with aluminium cellular elements located between them. It was found that compared with the control samples, the samples exposed to microwave electromagnetic field have an increased modulus of elasticity by 31.8%. Limit shear stresses also increase by 29%. Thus, the treatment of formed and cured polymer composite materials with built-in cellular metal structures in the microwave electromagnetic field is possible and allows to perform hardening quasi-structuring of such products and increase their performance parameters.

For the present significant progress has been made in understanding additive manufacturing processes Additive manufacturing techniques such as selective laser melting and laser-based directed energy deposition are widely used, but in comparison, electron-beam melting offers two unique advantages that are particularly important for titanium alloys: a high-vacuum medium and a preheating capacity for both substrate and feed material. This work describes experimental studies of a component built from 321 stainless steel and Ti-6Al-4V. The coating was formed through deposition of a wire with the use of a high-voltage electron beam in the high-vacuum medium. Two materials of deposition on the substrate were carried out in this study. As a result, 321 stainless steel composite coating can successfully form surface with gradient microstructure during EBAM cladding process. At Ti-6Al-4V of compositions was cracked, which led to the destruction of the top of the sample. The presence the intermetallic compounds of the top of the sample adversely affected of the composite that cracking occurred in the material.

The article is about design of the active aircraft control sidestick. The disadvantage of the known frame constructions, apart from the large dimensions, is the difference in the dynamic characteristics of the channels when using the same actuators, because the mass of a frame mounted actuator is the load for a fixed base mounted actuator. As a result the kinematic scheme of an active control sidestick which don't use a frame is offered. The frameless scheme contains two identical actuators mounted on the fixed base, at that the interference of channels is excluded. The derivation of the actuator's gear ratio is given. It is shown that this dependence between the rotation angle of the actuator output shaft and the handgrip deflection angle is of a sinusoidal type and that it is close to linear in the range of the handgrip operating angle.

In the present article, the questions of using the materials with mechanoluminescent properties as impact indicators are analyzed. The class of substances that exhibit mechanoluminescence (ML) the most intensively is revealed. Various designs of ML transducers are considered. The mechanism of ML radiation, which is based on the interaction between the mobile charged dislocations with the luminescence centers, formed by the activator atoms, are considered. Space charge of the moving dislocations causes tunneling of electrons to excited state with the subsequent radiating transitions. The problem of calculation of elasto-plastic strain of the transducer was solved by means of the microdynamic theory of plasticity. Equation of the intra center ML kinetics is given, with separate calculation results. The major features of the output optical signals of ML transducers on impact is analyzed.

The analysis of problems and tasks in the field of technology editing. A block diagram of an automated complex for stabilized straightening of low-stiff cylindrical parts by cross-rolling with smooth plates is presented. A block diagram of a software package has been proposed, the main function of which is to automate the straightening of cross-facing with smooth plates, as well as to provide all the technological parameters of the process. To improve the productivity of editing and automation of operations, new automated devices for editing low-stiff rigid cylindrical parts such as shafts and axles have been designed.

The paper describes a computational program developed in MatLab Simulink, that performs calculation of electric power generated by photoconverters for various missions of nanosatellites in low Earth orbit (LEO). Electric power generated by nanosatellite's solar panels was estimated for polar LEO of 450 km altitude for two versions of the satellite's static orientation. The results show how orientation maneuver at the Earth's surface point affects power generated by the satellite's solar panels.

A comprehensive analysis of the shrinkage process during the crystallization of aluminum alloy castings was carried out. An assessment was made of the general nature of changes in filtration and shrinkage rates, as well as the width of the mushy zone, depending on the rate of crystallization of the melts. An analytical expression was proposed for determination of the critical value crystallization rate of the alloy from the standpoint of the probability of hot tearing in castings. The method of influence on crystallizing melts by vibration with the aim of reducing hot tearing is considered and experimental data confirming the effectiveness of this approach are given.

The problems and prospects of cooperation between Russia and Kazakhstan in the space industry are revealed, the significance of Baikonur and «Vostochny» cosmodromes in this process is revealed. The concepts of geospatial information, earth remote sensing data, trends in the spread of space research in various spheres of society are considered.