A nonstationary dynamic contact thermoelasticity problem on sliding with friction and frictional heating of the rigid half-elastic coating surface bonded to an elastic substrate made of another material is considered. The solution to the formulated initial boundary value problem is obtained in the form of contour integrals of the inverse Laplace transform. The investigation of the isolated singularities of the subintegral functions in the complex plane of the integration variable is carried out, and then the problem solution is constructed in the form of infinite series over the poles of integrands with the addition of the integrals over the banks of cut. Boundaries of the stable and unstable problem solutions are determined on its dimensionless parameter set. The influence of the compliance of the substrate on the instability boundary, and also on the development of temperature and pressure at the thermoelastic frictional sliding contact is investigated.

Three types of self-simulated replacements for the problem of thermal convection averaged over a thin layer of the vaporizing liquid are presented. It is a model of the drying non-viscous extended droplet specified by the non-thermal diffusivity. For the construction of self-simulated solutions, a transition to the Riemann invariants is performed. Self-simulated solutions are functions of time and position determining the drop height, the mass-transfer rate and the heat flow averaged over the drop thickness. The found self-simulated solutions are classified on the basis of the behavior of the function that describes the drop height under the evaporation-condensation. The domains of applicability of various self-simulated solutions to the simulation of different situations of drying drops and films are identified.

An axisymmetric contact problem of the elasticity theory of the rigid rough-surfaced spherical punch indentation into an elastic transversely isotropic half-space with the functionally-graded transversely isotropic coating is considered. Elastic moduli of the coating vary with depth according to the arbitrary continuous or piecewise constant independent functions. The technique based on the integral transformations is used to reduce the problem to the integral equation. The punch roughness is modeled by the Fourier-Bessel series. Special approximation for the kernel transform is used to obtain the approximated analytical solution to the integral equation. The resulting solution is asymptotically exact for both small and large values of the relative thickness of the coating. A method of construction of the compliance functions is presented for the case of the simultaneous action of the arbitrary axisymmetric normal and tangential loadings.

The experimental results of the heat flux critical density studying under the unsaturated boiling of the binary mixtures of water-n-butanol and water n-pentanol within the concentrations from 0 to 100% by weight of the organic component are provided. The compositions with the maximum (peak) critical heat flux in the binary liquids under study, are determined. At that, some paradoxes in the boiling of these mixtures and in the singularities of the curve shapes qкр(х) are revealed. The comparison of the research results obtained in the area of the binary mixtures boiling with the earlier data is carried out. On the basis of this analysis, it is concluded that the critical zone of the heat transfer is connected with the existence of the thermal energy flux limit under the binary liquid mixtures boiling. The incoming energy density is limited by the environment through which it flows. This fundamental regularity established by the authors can be interpreted as a law of the energy flux limit in the environment.

The investigation objective is to develop a calculation method of selecting the optimum cutting speed corresponding to the minimum tool-wear rate. The analysis of the known optimization criteria such as tribological, thermal, energy and thermodynamic ones is made. The characteristics of their optimality through the cutting velocity (friction) are identified. Particular attention is paid to the experimental thermodynamic optimization criteria reflecting the fluctuating nature of friction and wear which are developed in Don State Technical University. It is shown that the maximum values of fluctuation criteria through varying the cutting speed characterize the increased dissipation capabilities of the cutting area. The formula for calculating the optimum cutting speed under the conditions of thermal balance on the lathe knife pads is determined. The formula contains cutting mode elements, tool geometry, contact loads and the deformation characteristic of the cutting process - chip velocity factor. The proposed analytical dependence allows selecting the optimum condition using calculations without costly wear resistant experiments.

He work objective is the presentation of the main aspects of the flexible monitoring system of the mechatronic processing machines state including the multioperational computer-controlled machines. The basis of such a system is considered the abandonment of the response strategy to failure in favor of a flexible proactive and predictive maintenance. A variant of the flexible system implementation based on the intelligent technologies is proposed. The basic principles of the flexible monitoring system that makes possible the adaptive capability to the unfolding situation are proved. They include combined neuro-fuzzy subsystems to implement such features as the selection of various types of technical maintenance, the determination of the urgency of its carrying out, the choice of the service facilities, and making the recommendations on the feasibility of the technological mode change at work within the border area of the machine runnability.

The aim of the research is to study the possibility of the accelerated formation of a highly-rigid carbide coating on the surface of steel products. The use of the microarc thermochemical treatment technology is proposed. A steel article is placed into the black coal powder and is heated by transmission of the electric current. The formation of the microarc discharges in the powder environment leads to the carbon saturation of a surface, and the simultaneous diffusion in metal allows forming a highly rigid carbide layer. The possibility of ferroalloys usage as a source of the carbide forming metal under the formation of a highly rigid coating with the help of the microarc chemical heat treatment is established. The electrical conductivity of ferroalloys is higher than chemical combinations, and it allows obtaining acceleration of diffusion saturation due to the intensive formation of the fissile atoms of metals under the influence of microarcs. The application of ferroalloys is more favorable in terms of power, as restitution of metal oxides to an atomic state requires additional energy cost. When using ferrochrome, ferromolybdenum and ferrotungsten, a surface carbide layer up to 160 microns thick and with microhardness to 18 hPa is formed.

The methodological basis for an estimation of the dynamic properties of a technological vibrating complex is offered. The selection rationale of parameters is made through the structural mathematical model approaches. The automatic control system architecture equivalent in the dynamic relation to the settlement scheme in the form of a solid body with elastic supports is developed as part of this approach. The structural mathematical modeling for the analysis and dynamic synthesis problems involves using the system transfer functions. The concept of the transfer function of linearized connections which interpretation specifies the conditions for the implementation of the necessary distribution of the vibration amplitudes or the form of oscillating field is introduced. The choice of the working conditions of the technological complex is characterized by such a distribution of the mechanical oscillating system parameters when points of a certain area of the vibrostand work table are reduced to a mode or a state of dynamic oscillatory damping. The design procedure of the parameters providing necessary dynamic interactions of the system elements is offered. The sequence of actions for selecting values of the vibrostand baricentric parameters is developed; analytical relations for the definition of frequencies and the corresponding frequency characteristics are obtained.

The work objective is to develop a new modified microacoustomechanical noise-immune gyroscope. It allows converting the angular rotation velocities of the support base into electrical signals on two axes of rotation simultaneously. In addition, the valid signal level is increased compared to the noise interference level. This explains the expandability of the new modified microacoustomechanical gyroscope compared to the existing analogues. The operating principle of the modified gyro is specified in detail. The concept of its design and performance is explained in drawings. The proposed technical solution is protected by the Russian Federation patent for the invention. The proposed gyroscope can be used in the navigation, positioning and control systems of various mobile objects in aviation, rocket and space technology, robotics, etc.

The research objective is to study the development of the noise spectra patterns in the operating area of copy mill operators. The experimental studies have shown that among harmful factors specific to these machines, there is an octave sound pressure level increase up to 15 dB in the idle mode and up to 15 dB under woodworking. These data suggest that the main noise source creating excess over the maximum permissible values is a spindle unit, and in particular, the spindle case. The vibration measurements on the machine carrier system have confirmed the results of the noise monitoring. The main source of the increased vibration levels for these machine tools is spindle rolling-contact bearings.

The work objective is to introduce the visualization of the project main parameters into the design methodology to accelerate the adoption of constructive solutions while maintaining the geometric dimensions accuracy and their reference to the technical requirements. The task methodology provides the usability of programming, and the parameter analysis of worm gears that determine their performance. The calculation results are formed in arrays which serve as the basis for constructing two types of charts. For obtaining graphs of the functions of center distance from the transmitted torque, the most used formulas for the design calculation of worm gears on the contact endurance for the averaged values of the load ratios, gear ratios and the initial parameters of the gearing are used. The data are divided into three groups of materials with the appropriate allowable stresses, and into two kinds of worm profiles (line and not line). To gain the functionality of sliding velocities from the center distance, the velocities for lists of standard center distances and gear ratios are calculated. The results are a group of charts based on center distance up to 500 mm covering the entire standardized range from torques up to 20,000 Nm. The second group of graphs (dependences of sliding speeds from the center distance) is made for gear ratios up to 80, with rotational speed of worm 750, 1000 and 1500 rpm. The recommendations for selection by standard depending on the set rotation frequency of the worm are developed. The work performed allows concluding that graphs of the mutual dependence between parameters, geometry, loads, and kinematics of the worm gears create a range of rendering capabilities for a good scope of the main parameters selection. Depending on the application area, the graph parameters can be extended or stretched to the desired range without changing the principle of construction. The application of the described graphs allows a developer to reduce significantly the calculations cycle of slip speed and spacing under the contact endurance condition closed on the properties of the chosen transfer materials.

A device for measuring the magnetic component of the electromagnetic field is proposed. Magnetodiodes are offered to be used as an electromagnetic field-intensity meter sensing element, and the holometry method - to improve the sensitivity. The proposed meter consists of the standard antenna connected to the calibration generator output, and of the series-connected magnetodiode, filter, processing amplifier, interference-holographic system, and measuring device. The calibration oscillator is made tunable. The application of the discussed above method of measuring the magnetic component of the electromagnetic field will allow significantly improve the accuracy and ease of measurement, will make it possible to create highly sensitive, compact, relatively easy-to-work tools that provide the capability of interfacing with a variety of the output devices and information visualization. In addition, the periodic meter recalibration under the steady-state conditions in the technical center is eliminated. The meter calibration is used for the permanent and timely correction of the changes associated with aging, temperature, pressure, and vibration.

The work objective is to study the impact of the thermal welding cycle (TWC) and reheating on the metal embrittlement kinetics of the heat affected zone (HAZ) of 15H2NMFA-VRV steel joint welds. The problem of the technological strength improvement of the welded joints of the nuclear power plant equipment is solved. A comprehensive study, in which various types of analysis - fluctuation, metallographic, electron-microscopic, X-ray and chemical - are used, is carried out for this. In addition, HAZ metal simulation is used, as well as non-destructive and destructive testing of welded joints. The effect of the basic parameters of TWC and heat treatment on the embrittlement kinetics of HAZ metal is determined. It is shown that the high heat input under the electroslag welding is the main cause of the direct borders softening of the coarse grains (0-1) through allocating sulfide film forms. Further development of the dispersion hardening under reheating (softening) stimulates the relative weakening and borders destruction.

The research objective is to study regularities of the noise spectra development at the working sites of locomotive brigades created by the sound radiation of the internal noise sources, and the conformity octave sound pressure levels to the sanitary standards. The investigation results are given. The measurements are carried out on freight and passenger locomotives by the noise and vibration analyzer “Assistant Total+”, accuracy rating 1, with preamplifier PU-01 and MIC capsule МК233 with a frequency measurement range from 2 up to 40,000 Hz. The experimental studies have shown that almost all the internal noise sources produce the sound pressure level increase above the maximum permissible values.

The study objective is to develop a method for calculating the plain journal bearing with an adapted profile of the bearing surface operating on the micropolar lubrication. Furthermore, it is assumed that the micropolar fluid viscosity characteristics are temperature dependent. Partial filling of the front gap with lubricant (i.e. availability of a free surface) is considered. Except regular dimensionless parameters of Newtonian fluid theory, other options for micropolar liquid are introduced, namely the interaction of N and N₁ parameters characterizing the dependence on the size of the grease molecules. The numerical analysis shows that with the heat parameter ( К ) increment, the carrying capacity of the bearing decreases. With the increment of the parameters and characterizing the adapted profile of the bearing surface, the bearing capacity increases. At the parameter point of =0.5, maximum load capacity is achieved. At the bearing capacity value tends to the corresponding value for the case of Newtonian lubricant

The work objective is to obtain an integral equation by which, using the known fundamental solution to the other equation, it is possible to find a fundamental solution to the linear elliptic equation. The concept of a numerical fundamental solution (NFS) is introduced. The so obtained numerical fundamental solutions (NFS) can be used for solving boundary value problems for N-dimensional elliptic equations by the field point source method (PSM). The research result is the development of the effective numerical method for solving boundary value problems using the NFS. This allows expanding the range of solvable problems using PSM, making PSM a universal numerical method for solving boundary value problems for linear elliptic equations. It admits solutions to various types of boundary value problems. Especially effective is the use of the proposed method for solving three-dimensional Dirichlet problems for equations with spherically symmetric fundamental solutions. The Schrödinger equation for a one-dimensional quantum oscillator is solved by the proposed method as a test problem. It is shown that it is possible to find the eigenvalues and eigenfunctions of the quantum oscillator using numerically obtained fundamental solutions to the Schrödinger equation. The oscillator eigenfunctions obtained by the proposed method are in good agreement with the known analytical solutions to quantum problems. Then, as another test example, a two-dimensional boundary value problem for the Helmholtz equation is solved. In this case, it is necessary to obtain a numerical fundamental solution to the Helmholtz equation first. Dependences of the numerical solution error on the nodes number in the problem solution domain are calculated. Upon the results obtained, the following conclusion is made. The results of solving test problems confirm the efficiency of the proposed numerical method.

The paper objective is the preparation, processing and analysis of the expert information to determine the organization maturity level on the basis of the self-assessment. GOST R ISO 9004-2010 criteria are used to establish the maturity level. The following tasks are set: to determine the sequence of actions for assessing the maturity level of the organization, and to develop methods of generating the expert information that gives an adequate view of the actual situation. A mathematical apparatus of fuzzy sets theory is used to solve the problems. The preparation and analysis of the expert information is the gist of the fuzzification stage in creating an expert system. The solution to the problem is illustrated by a model example. Linguistic variables and additive and multiplicative indices of conformity are determined. Membership functions and matrices of consistency and of fuzziness indexes are constructed. The program system of expert information input is used to obtain these characteristics. Sufficiently high quality of the expert information and its applicability on the subsequent stages of the expert system operation are determined. The proposed methods can be applied both for the expert information generation under determining the organization maturity level, and for solving any problem of the development of the expert systems that operate on the basis of the fuzzy expert information.

The work objective is to develop and investigate a method of choosing between manual and automated testing of the software product (SP). The proposed method principle consists in the organization of the interaction routines between testers and programmers who have completed the coding and unit testing process. A special questionnaire of 20 points which is filled in by a programmer is offered. Thus, the obtained, processed and analyzed answers make assertions about features of the prospective software product performance valuable for a tester. As a result, a general connection between the properties that determine the software utility and the testing method is specified. When functionality and (or) the reliability checking is requested, it is recommended to use the mixed testing - both manual and automated. When usability and (or) maintainability checking is requested, it is recommended to use the manual testing. When productivity and (or) portability checking is requested, it is recommended to use the automated testing. The methods are aimed at improving the testing quality on the basis of GOST RISO/IEC 9126-93.

The work objective is to develop a special model of the complex distributed object - the cement production - on the basis of the colored timed Petri nets including its analysis and estimation of effectiveness and correctness. Various kinds of the Petri nets together with the methods of their determination and performance dynamics are considered. An operation algorithm is formulated in the matrix form for the colored timed Petri nets. On the basis of the colored timed nets, a mathematical model that allows predicting the cement production volume for a defined period is built. The discussed model is realized in the C++ language. The simulation results are compared to the factual data. It is found that the implemented model with a reasonable degree of accuracy predicts the output volume of the cement production. The developed methods are operable and applicable in the manufacturing process simulation as part of an automated control system of the technology parameters.

The work objective is to study the four-layer scheme convergence rate. The problem of finding an approximate solution to the linear operator equation Au = f is considered. Two-layer and three-layer iterative methods are used to solve this problem. At that, the three-layer conjugate directions methods converge faster than the two-layer gradient methods. The research problem is to establish whether the four-layer scheme has a speed advantage as compared to the three-layer scheme. The four-layer scheme is constructed, and its parameters are calculated for this purpose. It is proved that the four-layer iterative scheme of a variational type for solving finite-difference equations downs to the three-layer scheme.

The investigation objective is to simulate the process of generator frequency stabilization as in the case of a component of the cellular system “switching centre - base station”. The aim of the work is to establish dependences between the generator parameters (a number of generators, operation frequencies, and relative instability of frequencies) and the generator frequency stability. The study is based on the application of the numerical analytic model of the generator signals, and on the construction of the plausibility function when the unbiased, asymptotically efficient and consistent estimates of each generator are specified from the maximum condition. The research suggests the following results. Under the cooperative processing of the measured values of the signal phases of the simultaneously and independently operating generators, the unbiased, asymptotically efficient and consistent estimates of the generator frequencies may be obtained. This ensures the frequency stability augmentation. The use of the numerical simulation allows estimating gain in reducing the relative instability of the frequency signals depending on such infocommunication system parameters as a number of generators and their relative instability.

The work objective is to establish the relationship of such soil parameters as soil moisture (SM), penetration resistance force (PRF), and time of the compressed air release. During the investigation, the following tasks are solved: identifying the impact of humidity on the air permeability of various types of soil; establishing the relationship between the soil PRF and the air permeability of the soil types under study; gain in experience of using a penetrometer for measuring the penetration resistance force of different types of soils. The connectivity between humidity and soil penetration resistance force is proved. At that, the highest correlation coefficient is observed in limestone, and the lowest - in alumina and sandy loam. The relationship between the content of pores filled with air, and the air permeability of the soil is determined. The number of pores filled with air ( ) increases with the decreasing of the number of pores filled with water. Whereas the compressed air release time ( ) decreases over the natural logarithm amplitude: