The work objective is to investigate the possibility and efficiency of three-dimensional numerical models of the elastic stress fields in the deformed solids. The field point-source method (PSM) designated as the method of fundamental solutions (MFS) in the foreign literature is used to develop these models. The PSM system generation for modeling fields of different physical nature is described. The concept of a point source of the elastic displacement field in the deformed solid is introduced. The research result is a developed PSM equations system that can be applied for solving three-dimensional problems in the elasticity theory, including the classical first and second boundary value problems in the elasticity theory (when either the voltage or bias is set on the boundary), as well as a mixed boundary problem (when on one part of the boundary, the displacement is set, and on the other - the voltage). The PSM properties are studied when solving standard problems, and the Dirichlet problem for a circular domain. The dependences of the numerical solution error on the problem parameters, in particular, on such as the charge number simulating the desired field, the remoteness of the charges from the solution domain boundaries, are obtained. The test problem of calculating the deformation field in the ball domain is solved. Upon the results obtained, the following conclusion is made. In the numerical solution of three-dimensional elasticity problems, a decreasing exponential dependence of the PSM error on the square root of the simulating charge number is observed. This property provides a numerical solution with a very low relative error that implies the PSM application perspectiveness in the numerical solution of the elasticity problems, including three-dimensional problems.

The work objective is to improve the operational conductometric vapor quality control at the thermal power plants. To this end, methods identifying СО₂ concentrations in the vapor under the neutral aqueous-chemical mode without ammonia addition are developed. The technique of measuring the steam condensate conductivity at the operating pressures of steam generators and at different temperatures is used. The implementation of this method with the use of a special device significantly reduces the control response rate and differentiation of impurities. The experimental data on the first apparent dissociation constants and the limiting equivalent conductance of the carbonic acid, dissociation constants, and the limiting equivalent conductance of NaCl in the liquid phase on the saturation line are analyzed. On the basis of this analysis, an error in determining СО₂ concentration and the impurities in vapor in the form of NaCl by the proposed method is estimated. The approximation error for the dependencies describing the dissociation constants behavior, and the limiting equivalent conductance of the carbonic acid, which can be used in the calculation of the concentrations by the proposed methodology, as well as during the organization and management of water chemistry, is estimated.

The algorithm simulating the initiation and development of fatigue cracks in the joint weld on the example of the mount of the mobile platform and the supporting cowl of Gottwald NMK 170 EG (63 tons) crane rotator, the destruction of which occurred in 2011 in the territory of “Novorossiysk commercial sea port” OJSC (NCSP), is worked out. The proposed algorithm takes into account the non-uniform weld geometry affecting the value of the stress concentration factor and the uneven distribution of the rated stress related to the joint design features. The modeling process is based on the experimentally established fact that the geometry profile of the junction between the weld and the base metal along the welded joint changes randomly. As a result, the fatigue flaking along the weld lacks any regular pattern. Under the cyclic loading, the development of the destruction is a sequential process of the crack nucleation in different parts of welded joints along the weld, single surface cracks growth under the fracture mechanics laws, nucleation of new cracks, and crack coalescence in the adjoining sections. At the coalescence of the crack edges, the contour profile is changing which leads to increasing the growth rate of the crack depth. In the future, the development of the multicentric destruction continues until the critical crack. The damage accumulation and destruction development rate depends on the uniformity coefficient of the stress concentration along the weld. The implementation of the proposed model allows solving the problems of determining the frequency of node diagnosis and the points with the utmost probability of fatigue cracks initiation, as well as validating the possible methods of structural reinforcement.

The ion-plasma sprayed titanium nitride (TiN) coating on the prepared 40Cr steel substrate is investigated. A part of the coating surface was covered by the copper foil mask to measure its thickness afterwards. The properties and characteristics of the sample surface microtopography before and after coating deposition are studied by the atomic-force microscopy (AFM). The technique for the high-precision determination of the coating thickness using the results of the AFM scanning of the transition area between the substrate and the coating on the sample surface is described and applied. The calculated uncertainty of the measured value of thickness is significantly less than in other methods. Mechanical properties of the coating are measured by the instrumental indentation method; the significance of an accurate determination of the correct thickness for measuring the coating characteristics by the indentation technique is shown.

The work objective is to introduce a design of the automated pneumatic drive (APD) with an external braking gear. It is a controlled pneumo-mechanic brake providing the process time reduction, the positioning accuracy increase, and the reliable positioning of the stop mechanism in the setpoints. The application of the prototype drive with the automated measurement complex creates conditions for the oscillographic testing of the positioning process in real time and space, and it also provides reliable experiment results. The authors have created a special stand - a model of the proposed drive that allows investigating the effect of its positional accuracy under different parameters of its operation. Kinematic and power characteristics of the drive in the automatic operation by the compressed air flow are identified. The effect of the positioning speed and the brake control pressure on the drive accuracy is resulted. Recommendations for the development of real positional drives with increased performance and positioning accuracy are formulated. It is found that the introduction of an outer braking device - the controlled pneumo-mechanic brake - improves the positioning accuracy of these drives by 1,25-2,25 times.

The calculation of the temperature field for the tribosystem of wheel - composition brake shoe of the rolling stock has shown that the maximum temperature in the wheel is not on the surface, but at 200-1000 micron distance from the friction surface. Under friction, as a result of the thermomechanical destruction of the polymer shoe there evolves hydrogen that is absorbed by the contact surface of the wheel. At that, the maximum hydrogen concentration coincides with the maximum temperature. The research results of the segregation phenomena of alloying and impurity elements in the iron grain boundaries are presented. It is shown that the consistency of the rates of the transfer film formation and its destruction is the kinetic condition of self-organization on the antifriction tribo-contact. The atomic-binding energy of different elements to the grain surface is a periodic function of the atomic numbers of the elements. This may serve as a theoretical basis for predicting the strength properties of steel with a different composition of alloying and impurity elements. The obtained results indicate the promising application of XPS and AES of quantum chemistry in solving tribological tasks.

The work objective is to study the effect of the alkanoic acids nature on the tribotechnical characteristics of the “bronze-aqueous solution of carboxylic acids-steel” friction system. The tribological tests are carried out on the end-type friction machine AE-5. The sedimentation analysis using the disc centrifuge CPS Disc Centrifuge Model DC24000 is carried out to determine the wear particle size. The surface roughness of the servovite film is determined with the aid of the atomic-force microscope PHYWE. The friction factor fall with increasing the strength of the acetic and glycolic acids, and its growth with the increase of the oxalic acid content in the lubricating medium is observed. When the acid concentration in the lubricant composition and in the oxalic-acetic-glycolic acid series is increasing, the wear factor of the friction couple decreases. With increase in the mean wear particle size in the glycolic-acetic-oxalic acid series, the friction rate increases. The servovite film being formed in the aqueous-glycolic environment on the steel disc surface contains oxygen. The oxygen percentage in the film depends on the specific surface of the nanostructured system.

The work objective is to provide stirred tanks with a swinging movement of impellers, as they differ from the other modern devices in higher intensity and uniform mixing. Synthesis of the actuator diagrams is carried out by the structural mathematical models. As a result, the leverage and gear units with one or two independent closed loop circuits are obtained. Four-bar linkage and a planetary mechanism with elliptical gearwheels under the appropriate dimensioning of the links are converting rotary mode into reciprocating rotation. The application of the gear and continuous drive allows creating a set of structural diagrams which differ in the number of impellers and their location. On the basis of the developed structural schemes, high-efficient stirrers for the chemical, petrochemical and food industries can be worked out and designed. The advantage of the proposed mechanisms is that they are developed from the known, well-established, and highly reliable devices. Besides, the impellers are well configured throughout the total reactor volume creating a rational heat-mass exchange.

Increasing the operational life of the cutting end of the metalworking tool through face-hardening with powdered materials is an urgent task. The emphasis is on the research results in the field of electric sintering of powder materials in combination with mechanical pressure. The following perspective methods of the powder materials consolidation are described: electropulse compression (EPC), electro-discharge sintering (EDS), and electric pulse sintering (EPS). The devices for dynamic loading of the powder compositions - pneumatic press, magnetic hammer -are analyzed. A compatible scheme of the pulse compression process implementation - sintering with an inductive-dynamic drive which allows synchronizing the thermal and mechanical effects on the powder composition - is submitted. The process parameters dependencies on the time when the duration of the current passage making a thermal impact does not exceed 200 ms are presented. The possibilities of the pulse process are described.

The work objective is to study a vital task of the multiextremal objects search engine optimization which is much more complicated than monoextremal problems. It is shown that only heuristics is appropriate in achieving this goal. Therefore, three best known and developed search engine optimization techniques are studied: particle swarm method, evolutionary genetic approach, and ant colony algorithm. The analysis is performed in the environment common for all methods of the test research problems of the multiextremal Rastrigin function. It is proved that all these methods are well suited for the multiextremal problem solution. While it is necessary to use proper specific approaches to solving the local extremum detection and identification problem in each of the heuristic algorithms, they all require data clustering. Each method can provide any desired accuracy of the extremum problem solution, and it utilizes an acceptable time resource.

Considerations of the system physical features in the form of its invariants allow advancing in the solution of the problem of terminal control structural synthesis. It is achieved by using the acceleration energy when forming an extended objective functional that determines the difference of the obtained result from the known ones. The application of the device of asynchronous variation has led to the establishment of the necessary and sufficient conditions for a minimum target functional. On its basis, the boundary-value problem equations for Appell dynamic systems are obtained. Their final form is determined by the synthesis purpose. The development of these equations should be performed for specific cases. The validity of the results obtained is confirmed by the results of the terminal control problem solution. For linear systems, the offered method allows obtaining the exact analytical solution. The synthesized control provides the nonimpact change mode of the dynamic system condition.

The present research subject is the secure document management. Its purpose is increasing the reliability of the data transmission. The research problem is the construction of a reliable model of the secure document management with authentication. The distributed data transmission technique which allows - using multiple channels - reduce significantly the risk of the unauthorized access to the information, and the possibilities of its modification, is used to solve this problem. The research result is a secure document management model based on the dual-link MV2 cryptoalgorithm, and AES and RC4 underlying ciphers. The replacement of the basic ciphers is provided, and the need of the additional associated data which must remain open, but be authenticated with the basic encrypted information is considered. The model constructed solves the original problem, and the software implementation developed in C ++ using NTL library can be applied in practice. The application field of the results obtained is the commercial document management protection.

Bayes' formula is the research subject. The work objective is to analyze the formula application and widen the scope of its applicability. The first-priority problem includes the identification of the Bayes' formula disadvantages based on the study of the relevant publications leading to incorrect results. The next task is to construct the Bayes' formula modifications to provide an accounting of various single indications to obtain correct results. And finally, the incorrect results obtained with the application of Bayes' formula are compared to the correct results calculated with the use of the proposed formula modifications by the example of the specific initial data. Two methods are used in studies. First, the analysis of the principles of constructing the known expressions used to record the Bayesian formula and its modifications is conducted. Secondly, a comparative evaluation of the results (including the quantitative one) is performed. The proposed modifications provide a wider application of Bayes' formula both in theory and practice including the solution of the applied problems.

The simplest topological properties of the approximate spectrum, namely the connectivity of its complement in the complex plane, are studied. A numerical verification of the lower bounds for the maximum number of the connected components of the limitary spectrum complement of the band Toeplitz matrices whose symbol is Laurent polynomial of the specified degree, is carried out. The algorithm for computation of the Toeplitz matrix symbol parameters with its approximate spectrum dividing the complex plane into a given number of connected components is adduced. The examples of polynomials which are Toeplitz matrices symbols with the limitary spectrum dividing the complex plane into a given set of connected components are numerically investigated. Graphs of the limitary spectra of Toeplitz matrices illustrating the results obtained are given. The obtained limitary spectra are compared to the Toeplitz matrices spectra of large size with a given symbol.

Improving the customs control mechanism is a priority for the Federal Customs Service, as the customs control should be aimed, for one part, at the streamlining and acceleration of the customs formalities, and on the other part, at the defence of the State interests. As it is known, the choice of the customs control forms is based on the principles of selectivity and sufficiency. In this regard, it is often necessary to identify the baggage that may contain prohibited goods with the purpose of the authentication of the persons who move these goods. The work objective is to consider the use of various systems of the nonintrusive identification of the objects that are commonly applied in the anti-theft systems for identifying the baggage containing items that are prohibited or restricted for carrying across the customs border.

The research objective is to investigate the key reliability man-agement techniques for the agricultural machinery. A servicea-bility strategic management technique is used to study this issue. The analysis allows assessing strengths and weaknesses of the methods used to improve the reliability of products. The reliability management techniques during the current and scheduled repairs, maintenance work, as well as methods based on the queueing theory, are described. The application of each of the techniques at different operational stages contributes to the reliability engineering. Thus, the need for the problem solution to specify a number of theoretical distribution laws is ascertained. It is shown that the routine maintenance and repair timing shall comply with the deadlines to meet the requirements of the technical specifications for the reliability of the equipment in operation.