Modeling of the non-destructive testing system of defects in solids is performed. Specifically, the inverse geometric problems of the elasticity theory for a flat rectangular area on reconstructing circular cavities and cracks breaking the body surface are considered. Additional information for solving these problems is a setting of the first four natural resonance frequencies. The inverse problem solution is based on the minimization of the residual functional between the measured input source information and the data calculated during the numerical solution of direct problems with the given parameters of defects. As a tool for solving direct problems, the finite element method implemented in FlexPDE program is used. The functional minimization is carried out by using a genetic algorithm (GA) implemented in the developed GAFEMNDT program. The program algorithm and GA settings used in the numerical experiments are described. The experiments results on determining parameters of defects (coordinates of centre, radius, coordinates of surface cracking and its size) are presented. The results demonstrate adequacy of the additional information to overcome the problem ill-posedness, as well as high efficiency of the proposed algorithm both in accuracy of detecting defects parameters, and in their search speed.

The study object is a “wheel - rail” system. The subject is the computer simulation of the system elements wear. The work objective is to investigate the wheel and rail wear dependence on the kinetic performance parameters. The problems solved here are analysis of the earlier proposed mathematical functions describing the kinetic performance for the presence of extremes, the functional behavior (growth, decrease, monotonicity, and unimodality, etc.) in various parameter ranges; implementation of the computer simulation of the wheelpair movement by rail with the quantitative estimation of the wheel and rail wear with various kinetic performance parameters; to determine qualitative influence patterns of the kinetic wear performance. The simulation is fulfilled by the software package “Universal Mechanism”. As a result, values of various characteristics related to wear (power, total and specific friction work) under different conditions of the kinetic friction performance are obtained. The conclusions are as follows. The kinetic friction performance parameters must be considered as they can significantly affect the wear within the range of the actual operating conditions in the course of the computer simulation. Under some conditions, there are cases when an increase in the friction coefficient is accompanied by a decrease in depreciation. It is proposed to continue the research in two main areas: determining the influence patterns on the kinetic friction performance and wear of the multiple actual factors, and studying the dynamic (at variable slip velocity) feature of friction effect on the parameter wear through the same procedure.

The promotion of water in the systems of cylindrical capillaries is studied in detail. A mathematical model of the water movement in both symmetric and asymmetric capillaries connected to a vertical capillary is built. In this case, the radii of both vertical and angled capillaries are considered identical. General properties of the water movement in branching capillaries are determined on the basis of the mathematical model. In particular, the greatest promotion of water occurs in the lower level of the capillaries. It is found that the shape of plants depends on the presence of capillary systems in them. However, the capillary systems of various parts of the plants differ in radii. For example, the diameter of the central capillary of a leaf is larger than that of the capillaries in the lamina. The patterns of water movement in the branching capillary systems with capillaries of different radii are considered. An expression for calculating the critical vertical capillary height at which water does not come from the vertical capillary to the inclined capillaries is obtained. It is shown that under certain conditions, the height of water in a vertical capillary can twofold exceed the height of water in a single vertical capillary of the same radius.

The work objective is to consider the stability problem of steady-state paths of the elastic deformational tool displacement under the longitudinal end milling. The authors analyze the case of high speed cutting in contrast to the previously discussed stability problems that analyze the case of slow movements for which the system parameters can be considered frozen in the equations in variations relative to the stationary path. In this case, the stability analysis must consider the linearized system in variations with periodically varying coefficients. With speeding-up the tool rotation in many cases there is a parametric self-excitation of oscillations. Therefore, the main attention is paid to studying the parametric excitation conditions of a dynamic endmilling system. It is shown that the parametric excitation condition is affected by the technological cutting modes, both the tool rotation frequency and the tool geometry which determines the matrix angular coefficients of the cutting forces orientation. Examples of stability areas depending on changes in the system settings are given.

The body of knowledge of the intelligent control system e-MindMachine of the multi-operation machine contains each tool condition data including its remaining life time. This is required to obtain conclusions on the possibility of the planned machining pass, the wear size value, the necessity to change cutting conditions during the operation in the fuzzy boundary strip area, etc. In addition to the previously described methods of assessing the initial and final values of the boundary strip time as an uncertainty state area, a visual method using a modification of Shewhart control charts is offered. The adaptive control charts allow tracking the tool wear progress warning of deviations from the requirements to the process. A program sheet with the appropriate control charts and examples of their usage for the assessing the tool state and forecasting the boundary strip parameters is presented. The dependences of estimations of the expectation of the wear size and scattering within the linear tool wear zone, appropriate velocity functions and a posteriori values for the future operation in the boundary strip area are described. On this basis, the timing estimation of the boundary strip head and end is predicted. The processing of the statistical control charts is performed by the MATLABStatisticstoolbox application package.

The subject of this investigation is the methods of switched reluctance motors controlling. The study objective is to review the existing methods of reducing shaft electromagnetic torque ripple in the switched reluctance motors. A comparative analysis of the existing approaches to valve drives control systems development is used to classify the electromagnetic torque control methods. The study results can be used when selecting the drive control method providing a balance between the complexity of the control system implementation and its effectiveness. On the basis of the comparative analysis, the conclusions on the neural network torque control systems effectiveness with offline learning are made; the control system enhancement using co-energy magnetic drive system as well as the inclusion of the residual magnetization material effects in the model is marked. It is noted that the existing systems aligning the magnetization of the actuator materials reduce the average torque for the work cycle.

The research subject is a multivariate analysis of the air-flow classification process of the straw heap with a predetermined fractional composition supplied to the cleaning after the drum destroyer. The work objective is to identify patterns of the air separation using three pneumatic ducts with a linkage parameter variation. The investigative technique is an analytical modeling. The effect of probabilistic characteristics of the heterogenic thrashed heap supply, airflow velocity distribution by the separator width, and density function of heap components terminal velocity on the separation is evaluated. The air-flow classification process on each section of the pneumatic duct is considered. To this end, the mathematical expressions averaging the air classification indicators of the consistently functioning three pneumatic ducts and a stochastic quasistatic mathematical model of the separator operation with three pneumatic ducts in series are used. The results of the separator parametric synthesis and its technological parameters are presented. The fractional constituents of the heap components and their percent-sizes in each air-classified fraction are shown. The possibility of the air-flow classification of the crushed straw heap in the predetermined factions at the preset productivity of 0.6-0.7 kg/m∙s is revealed. It is found that under the rational functioning of the air separator, the straw content in the service faction is 97.03%. In this case, the minimum grain content is 0.03%, and mineral impurities are 0%. It is revealed that the air separator with three pneumatic ducts in series is sufficient for separating the crushed straw heap with the predetermined agro-technical requirements.

The study objective is to review the prerequisites for reducing the time of transport movements of the road-building machinery. On the basis of the information received, the corresponding recommendations used in the performance control system and technical audit can be elaborated. Shortcomings of the existing monitoring systems are marked. It is shown that their application to improve the technical-and-economic efficiency of the road vehicles does not allow achieving the controlled results. The technical-and-economic effect should be assessed by the unit cost criterion taking into account the cost for ownership. To calculate such a criterion, it is necessary to have the source information that can be obtained by monitoring. At a minimum criterion, there are work performance and operating quality time limits. The possibility of implementing restrictions on the time performance which largely depends on the machine transportation operations time is considered. Transport operations, in turn, are determined by the stability level, so to elaborate recommendations on reducing the transport operations time it is necessary to evaluate the stability by special calculating formulas. Various options for calculating are considered, the option of differential rocking equations is selected. It is noted that the working process is better described by the loading workflow diagrams, so they should be built on the basis of differential equations. An example of the loading diagram construction for a front loader is given. The application of loading diagrams to elaborate recommendations on reducing the transport operations time is shown

The work objective is to describe the theoretical and experimental research of the vibration attenuation coefficient of the wage wheels on the electric locomotive underframe. Studying the vibro-acoustic characteristics at the workplaces of the locomotive crews shows that the excess of the octave sound-pressure levels over the maximum permissible values is largely determined by the noise structural component which is generated by vibrations of the body parts. The vibration velocity calculation is based on the energy methods traditionally used for the energy-closed circuits. The system of equations takes into account not only the geometric parameters of the elements, their physical and mechanical properties, but also the vibration power from the locomotive wheel pairs introduced into the base body under the speed conditions. For the engineering analysis of the vibration spectra of the body parts, and, respectively, of the sound-pressure levels when evaluating the introduced vibration power, it is expedient to use a frequency dependent value of the vibration reduction factor. This is especially important at the machine designing stage. Therefore, the results of the experimental study of the given value and the development of the regressional dependences for various motion speeds on this basis are presented.

The work objective is to develop a technique of evaluation and forecasting of the complex systems reliability based on the statistic simulation of their operation. A method of risks inherent in the lost benefit is used. Dependences for determining failure losses under the system operation according to the degree of its reliability are offered. A simulation program taking into account risks of reliability - “Reliabilify” - is worked out. The developed method verification is based on the performance simulation of the feed ingredient cutter, such as U17-UKI. The results obtained reflect real processes occurring in the course of the technical objects operation. The method is fully formalized and can be used for estimating the reliability of any engineering system.

A perspective method of disinfecting liquids and spreads in agriculture is considered. The principle of the method is about an integral physical and chemical impact of the rotating alternating electromagnetic field. The implementation of the proposed method is carried out in the electromechanical activator which is an inductor. The purpose of the research is to obtain mathematic models that are able to assess quantitatively the effect of the inductor mass on the parameters featuring the inductor performance quality. Current intensity, reactive power, total electric power in the inductor circuit, and magnetic induction, are chosen as such parameters. Methods of the instrumental measurement, statistic treatment and analogue-to-digital data conversion are used. The research results are presented by the mathematic dependences which can be used for designing new inductors.

Some features of heating and melting iron-rich pellets (IRP) by the method of charging the pellets through the axial ducts of electrodes are considered. When using this system of supplying iron ore raw materials through the holes in the electrodes, loose pellets fall into the impact zone of the electric arcs on the melt that ensures a high speed of their fusion. At the same time the technical-and-economic indices of the electrosmelting in the electric arc furnace (EAF) are improved. The use of the fuel-oxygen burners allow optimizing the IRP melting process improving the slagging conditions, heating, metal decarburization with post-combustion of final burning gases (CO, H₂, etc.) in the arc furnace.

The work objective is to study the effect of the graphical processor unit computational cores load level and memory access pattern on the memory bus bandwidth and scaling acceleration. The research subject is the problem of scalability of the parallel computing performance and acceleration. The following hypothesis is checked: while processing images for multi-core shared-memory systems, Gustafson - Barsis’s law is more crucial than the memory access template at the underloading of the GPU cores. The research methodology is a computational experiment with further analysis of the obtained results. The conclusions are as follows. The suggested hypothesis is proved. For that, a series of experiments on various heterogeneous computational systems with OpenCL standard support is conducted. The application field of the results obtained includes the development of algorithms and software for the highly parallel computer systems. The memory access template starts to place certain restrictions on the algorithm efficiency only when the load level of the computational cores is sufficient. Video cards with the private memory show more stable results in comparison to those which share memory with the central processing unit.

Band structure of solid solutions In_xGa_1-xN with sphalerite structure and with considerable percentage of indium (x = 0,25; 0,5; 0,6; 0,7; 0,75; 0,9; 0,95; 0,97; 0,99; 1,0 ) is calculated using the density-functional theory (DFT) and the cluster version of the local coherent potential method within the frame of the multiple scattering theory. The electron structure of the ternary solutions of In_xGa_1-xN in sphalerite crystallographic modification is compared; the interpretation of their features is given. The concentration dependence on the energy gap for the entire variation range of the indium content in the solution is obtained. The spin polarization effect of the states of In, Ga, and N for the alloys with the considerable percentage of In, as well as the transition of the ternary solutions of In_0.75Ga_0.25N into the of magnetic semiconductor state is found out. The magnetic moments of In, Ga, and N atoms, and the saturation magnetization in In_xGa_1-xN semiconductor system are determined.

The research subject is the technology of generating the multivariable data representation with using separate formation of dimensions and measures. The purpose of the study is to provide a full level of the user’s work automation at the formation of new data cubes. In the course of investigation, the following problems are solved: the sequence of generating intermediate data representations is determined; the correctness of these representations is studied; efficient algorithms for generating the representations and checking their correctness are developed. The theoretical basis is the methods of the inter model mapping. Herewith, a classical relational model is used as a source data model, an extended model of the multidimensional data with unbalanced hierarchies in dimensions - as a target one. The work result is the multidimensional data construction technology. Consequently, the results obtained can be used by the analytical departments at various enterprises in processing large data volumes. The proposed technology of the multidimensional data formation is the traditional OLAP-technologies development.

The work objective is to study a critical traveling salesman problem which is NP complicated task of the discrete optimization. It is shown that only heuristics is appropriate in achieving this goal. The result of the ant colony algorithm (ACA) and genetic algorithm (GA) sharing is presented for the problem solution. The point is that the problem is solved using only mutations of various types (without crossover). The investigated GA is improved by the elitist strategy. The testing is done on graphs of the middle and large dimension. An “elite” sample obtained by the ACA is improved by a mean of 11%. It is shown that the efficiency of the genetic algorithm depends directly on the number of ants in the generation, and on the number of algorithm iterations. Target function values are improved more than twofold after the introduction of the elitist strategy. Increasing the number of ACA runs raises the efficiency of the algorithm by approximately 2%.

The objective of this work is to provide an efficient tool of Reliability-Based Design Optimization (RBDO) for soil tillage machine design process in order to achieve designs with a required reliability (safety) level. An efficient methodology that controls the reliability levels for different statistical distribution cases of random soil properties is developed. This developed strategy is based on design sensitivity concepts in order to determine the influence of each random parameter. The application of this method consists in taking into account the uncertainties on the soil tillage forces. The tillage forces are calculated in accordance with analytical model of McKyes and Ali with some modifications to include the effect of both soil-metal adhesion and tool speed. The different results show the importance of the developed strategy to improve the performance of the soil tillage equipments considering both random geometry and loading parameters.

The work objective is to study dosing accuracy changes of the vibration measurer with an electromagnetic drive powered by the industrial network. The previously obtained dependences of the vibration measurer performance on the vibration frequency, amplitude and direction of the magnetic actuator, and on the properties of the dispensed material are used. These relationships are obtained at the pilot plant with the stabilized power settings. It is found that the supply from the vibration agitator of the industrial network significantly (up to 5%) affects the vibrator meter performance deviation from the given one that may become unacceptable when dispensing the ingredients requiring higher accuracy. To eliminate uncontrolled deviations of the dispenser performance from the stochastic variations of voltage and frequency, a voltage- and frequency-stabilized supply of the vibration activator electromagnet should be used.

The work objective is to study an advanced way of enhancing the nutritive value of the mixed feed by co-extrusion of the grain mixtures with chopped green legumes that differ in high content of vitamins and protein. The task of this investigation is an experimental determination of rational parameters and operating modes of the equipment for the extrusion process. Standard techniques are used to study the extrusion process when the properties of raw materials and modes of the extruder EC-75 (75kg/hr) change: extrudable mixture humidity, weight percentage of the chopped green mass in the mixture, and the extruder screw frequency of rotation at different feed rate of the mixture. The residual content of β-carotene as a quite valuable but impermanent component of the received product is used as a key marker of the process. The restrictive conditions are organoleptical properties of the product, humidity after cooling, and occurrence of the undistorted grain material. Energy efficiency of the process is evaluated by the criteria of the specific energy consumption. The study results of the extrusion process are as follows. Its optimal characteristics are determined: mixture supply is 60 kg / hr, mixture temperature at the matrix outlet is 120-125°C, content of the chopped green mass in the mixture is 14-15%, screw rate speed is 220-240 rpm with the specific energy consumption of 90-95 kW hr/t.

The work objective is to study issues of determining the hydrogen peroxide concentration. The task is to evaluate metrological aspects of the hydrogen peroxide decomposition. Alongside with a standard permanganatometric (analytical) method of determining the hydrogen peroxide concentration, a fairly new technique of the acoustic emission is considered. A new methodology of the problem solution developed by the authors is presented. The study has found that the hydrogen peroxide catalytic decomposition reaction is characterized by a strongly marked transient process at the initial stage. Further, the total number of pulses uniformly increases, and then the hydrogen peroxide concentration gradually decreases. The proposed method of monitoring the acoustic emission parameters shows high informativity and sensitivity. It is found that the spread in the experimental values obtained by the two methods is identical - 5 - 6% of the measured value.