The executed investigations have shown that it is possible to prepare sheet-like material for laser cutting economically viable and with small amount of power expenditure while using reverse jet cleaning for surface treatment. As compared to conventional jet cleaning technologies efficiency of the reverse jet cleaning is attributed to significant pressure increase (by 25–50 %) when the jet is interacting with the treated surface. The paper proposes a mathematical model on the basis of approximate energy method (upper-bound method) and the model is used for calculation of fracture pressure due to action of the reverse jet on the treated surface which consists of a corrosion deposit layer. A variational problem was solved within a framework of the developed model and the problem solution has made it possible to obtain a theoretical dependence for calculation of minimum fracture pressure value p_min in the point reverse jet impact with a barrier oretical dependence and it has taken into account yielding point of the deformed material ss, density of fractured material med material r, jet velocity u_стр and parameter of reverse flowing – jet reduction ratio l. Comparison theoretical data and experimental ones (experimental data have been obtained while using a differential pressure transducer ЭДП-30 and a spring dynamometer with measuring limits 25 and 80 MPa, respectively) has shown difference by 4–15 %. Determined insignificant difference between a theory and an experiment demonstrates that the obtained theoretical dependence is considered as a quite correct one and it can be used in engineering practice for prediction of power and kinematics parameters which are necessary for selection of the required pump equipment designed for realization of reverse-jet cleaning process.

Turning machining of such parts as shafts is considered as the most widely-spread method formanufacturing units, mechanisms and machinery. While doing so it is necessary to ensure high quality of shaft turning with the help of a hard-alloy tool (accuracy and roughness, stability and predictability of steel edge dimensional wear), maximum tool durability, resource of its service life and productivity. As it is known all these operational parameters of the tool depend very heavily on cutting speed. However absence of an analytical dependence for determination of optimum cutting speed value does not per permit to prescribe optimum operational modes at the stage of technology design process. The cutting tool can be subjected to mechanical, anrasive, adhesive, oxidation (chemical), thermal-fatigue and diffusion wear types depending on turning conditions. In this case wearing process consists of two wear types and one of them influences at a certain point on wearing process to a greater extent than the other one. Methodology for prescription of rational turning modes for medium and high cutting speeds ensuring maximum resource of the tool operation has been developed in the paper and it has been based on the analysis of the existing viewpoints about changes in the hard-alloy tool durability due to cutting speed while turning shafts. The range of cutting speed changes has been determined in the paper and it leads to an increase of the tool durability period and, correspondingly, turning productivity of 45 steel grade shafts while using the tool with T15K6-hard-alloy replaceable inserts.

. The paper presents results pertaining to investigations on influence of plasma jet parameters and fractional composition of initial powder on characteristics of two-layer composite coatings on the basis of nickel-chromium, and zirconium dioxide in the shielding elements. Optimization has been carried out on the basis of obtaining maximum powder use factor. A comparative analysis for dependence of the powder use factor in viscous metal layers of nickel-chrome and nickelaluminum on spraying distance shows that while having similar character of curves for the presented dependencies an absolute value of powder use factor is higher for nickel-chromium powder. It can be explained by a higher ductility of the latter and correspondingly smaller rebound of particles which are colliding with substrate. The investigation results for cross section microstructure in the formed coatings while using scanning electron microscopy are given in the paper. The paper considers cross section microstructures for ZrO2-coating and intermediate Ni–Cr layer. The submitted data reveal that an initial stage of the coating is characterized by porosity and an average pore size is of several micrometers, and in some areas its size reaches 20 mm. The microstructure of a Ni–Cr layer is characterized by lower porosity. Impact of compression plasma flows on sprayed coating leads toformation of fused oxide layer with thickness of 12–15 mm and contributes to smoothing of surface relief and formation of cracks on the surface which are preferably propagating into coating depth. Processing of oxide coatings by compression plasma also results in reduction of their porosity.

In order to prepare soil for sowing of agricultural crops it is necessary to have a number of engineering structures that ensure its qualitative treatment and protection from erosion. Modern equipment do not fully meet the whole complex of specified requirements. Application of tillage machinery being used for main soil cultivation is directed on suppression (destruction) of natural vegetation which is considered as the strongest competitor to cultivated plants. From the other side, vegetation on the Earth’s surface plays an important role for reliable protection of soil from erosion. Destruction of vegetation throughout the whole period of crop tending leads to the fact that the remaining cultivated plants are not able to protect soil from erosion by such natural aggressive factors as rain storms and strong winds. As a consequence, processes of soil structure destruction and losses of entire soil strata and its fertility occur in the geographical (landscape) envelope. Thus, equipment for primary and secondary soil tillage exerts double impact: from one side, killing of weeds takes place, and on the other hand, there is destruction (erosion) of soil structure and profiles of its geographical envelope. The soil, in the understanding of the earth, is the perfect place that gives life to plants and organisms, has a fertility. For the last 50 years analytical scope of physical processes occurring in the soil has been extended, physical methods for investigation of soil properties and application of technical equipment for assessment of physical-mechanical soil characteristics have got widespread use. However, there is no summative investigation on soil physics which includes and reveals thermodynamics, electrophysics and nuclear physics of soils. At the same time an integrated approach for studying such complicated object makes it possible to understand important nature of some processes occurring in the soil and to develop practical measures for fertility improvement and erosion reduction. The paper considers problems pertaining to deformation mechanism while forming soil structure and its compression under influence of external loadings: magnetic, electric, physico-chemical, gravitational and thermal fields and working organs of tillage tools.

The paper presents results of demand research for “park and ride” parking lots in the city of Kharkiv. The analysis of the previous research pertaining to demand for “park and ride” parking lots has been carried out in the paper. Disadvantages of the existing methods have been identified as well. A methodology in research on demand for “park and ride” demand for “park and ride” parking lots in the city of Kharkiv according to various characteristics. Distribution of traffic parking lots in the city of Kharkiv has been developed and it is based on modelling of transportation correspondence distribution on traffic networks and a questionnaire survey of car drivers. The obtained data have made it possible to segment the demand for drivers representing suburban areas according to frequency of visits to the city by private cars has been determined in the paper. Drivers’ satisfaction with their efficient movement through the city has been assessed in the paper. Segmentation of traffic demand in the places of possible locations for “park and ride” parking lots has been made according to urban transportation distance and on the basis of modelling distribution of transport correspondences. Quantity demanded for “park and ride” parking lots in the Kharkiv city in dependence to conditions for services has been calculated according to a questionnaire survey of car drivers. It has been established that conditions for parking services significantly determine the demand for “park and ride” parking lots. Analysis of segmentation results concerning the demand for “park and ride” parking lots has shown that under current condions demand for this type of parkings in Kharkiv is at rather low level and they are practically absent in case of 5 km urban transportation distance. Parameters demonstrating dependence of demand for “park and ride” parking lots on transportation distance through the city have beendetermined in the paper. The obtained results of the research are considered as initial data to study demand for “park and ride” parking lots.

Conventional ultrasonic systems contain concentrators of longitudinal type to amplify and transfer vibrations to a tool. Along with them, elastic rings with variable cross section thickness can be used effectively as concentrators for ultrasonic vibrations of acoustic systems. Their practical application requires a scientifically substantiated methodology for determination of geometric parameters. The paper provides substantiation of the method used to determine dimensions of annular concentrators with a variable cross section which can enhance effectiveness of the ultrasound equipment while performing various technological tasks. Visual analysis of acoustic waves radiated by annular concentrators has shown that the most intensive vibrations are produced in the most thin sections. Computer simulation of oscillations in rings with an external diameter of 50 mm and a variable cross section has demonstrated that the largest increase of vibration amplitude is achieved at a certain ratio of ring thicknesses and diameters. An analysis of numerical values for amplication factor of vibrational amplitude Kд has revealed that there is a limit boundary for the ratio of ring wall thicknesses which, in its turn, depends on the ratio of ring outer and inner diameters at certain values of hole axis eccentricity. The ratio of diameters is expressed quantitatively by the coefficient Kд. An analysis of the results concerning numerical calculations of amplitude amplification factor performed for the specified model of the ring having 50 mm diameter have illustrated that this ratio should lie between 1.3 > Kд > 1.15. The obtained results can be used in ultrasonic devices with annular concentrators in order to perform various technological tasks.

The paper considers improvement of physic-mechanical and operational properties of adhesive coatings after laser infusion with additional alloying В4С, ТаВ and МоВ. Influence of the laser infusion with additional alloying on structure, microhardness and wear-resistance of adhesive coatings of the Fe–Cr–B –Si system has been studied in the paper. While increasing a laser beam velocity microstructure is changed from equilibrium to quasi-eutectic. Presence of molybdenum boride and tantalum increases sensitivity of the coating to specific features of laser remelting. In both cases heat exchange conditions have been changed, a number of iron and chromium borides has been increased and due to this molybdenum and tantalum have been partially passing to free state that contributes to a disintegration of structural components. While introducing solid particles B4C into a coating they are dissolved in an iron matrix while being heated by a laser beam and under cooling they are isolated in the form of separated Fe an Cr boride inclusions. Laser infusion and alloying increase coating wear-resistance. Load increase from 30 to 70 Н improves coating wear resistance averagely by 15–26 % and wear resistance of non-alloyed coatings is improved by 26–43 %. An increase of melting rate and laser spot diameter does not exert significant influence on wear but an increase in overlapping coefficient leads to reduction of coating wear. Presence of solid particles in a coating and an increase in rate of melting by laser beam reduce coating wear resistance. Such rather complicated dependence of coating wear rate on conditions of laser melting and wearing process is due to a complex of structural and phase transformations which have contributed to formation of secondary solid inclusions and increased microhardness.

The article deals with one of the ways to control an actuator of the automated clutch control system. The aim is to design control of the electropneumatic actuator, to control its coupling with the acceleration valve on the basis of experimental research as well as to provide rational parameters of the automated clutch control system for the robotic transmission. The feature of the system is an acceleration valve in the design of the electropneumatic actuator to control the clutch. New links demand to adjust the way to control the actuator. The connection of Pulse-Width Modulation (PWM) with single power supply pulses to control electropneumatic valves is substantiated. The quantitative characteristics of single control pulses and PWM ones are determined. The error of operation accuracy for various ways of the control of the electropneumatic actuator to control the clutch of the robotic transmission is determined. Obtained separate PWM area is designed to suppress the initial hysteresis when the rod of the clutch actuator is moved. An algorithm for the operation of a clutch control system is proposed, taking into account the use of two modes of operation of solenoid valves. A graphical interpretation of the clutch control algorithm is presented, which gives an idea of the location of the constant signal feeding zones to the solenoid valve, as well as the operation areas of the solenoid valve in PWM mode. The control algorithm of the clutch booster provides a mode of guaranteed absence of excess pressure in the pneumatic cylinder after releasing the clutch pedal, provided that two normally closed solenoid valves are used. This configuration of the electro-pneumatic clutch control system allows the use of an emergency clutch release system in case of voltage absence. The reference algorithm for filtering the array of data coming from the feedback sensor, as well as the numerical values of the delay caused by the presence of a filter, are given.

The improved process flow differs from the known ones in the fact that the same photomask is used for formation of a channel stopper and metal contacts. Such approach has made it possible not only to decrease a number of the used phototomasks but it has also permitted to obtain a device with the required electrical characteristics. The paper presnts results of device and process simulation of bipolar static induction transistor (BSIT) manufactured in accordance with the improved process flow, measuring data of electrophysical parameters of its experimental samples and also comparison of simulation results with experimental data. At present there is a large quantity of software products that permit to perform physico-topological simulation of semiconductor structures. The device-process simulation is considered as a part of such simulation and it allows prior to obtaining experimental samples to determine process flow parameters at which the investigated structure will have necessary electrical parameters and characteristics. Thus the device-process simulation represents a certain “virtual production” for manufacturing semiconductor devices and microcircuits beginning from the startup stage of semiconductor wafer at production site and finishing by electrical characteristics measurements of the obtained structure. The BSIT device simulation being an analog of direct measurements of current-voltage characteristics has been performed with help of program system MOD-1D developed by the author. The BSIT model based on the fundamental system of semiconductor equations is mainly used for calculation of the BSIT current-voltage characteristics direct branch and its parameters and charge carrier recombination is described by Shockley – Read – Hall expression and equation depicting the Auger recombination process.

Accuracy in determination of coordinates for image having simple shapes is considered as one of important and significant parameters in metrological optoelectronic systems such as autocollimators, stellar sensors, Shack-Hartmann sensors, schemes for geometric calibration of digital cameras for aerial and space imagery, various tracking systems. The paper describes a mathematical model for a measuring stand based on a collimator which projects a test-object onto a photodetector of an optoelectronic device. The mathematical model takes into account characteristic noises for photodetectors: a shot noise of the desired signal (photon) and a shot noise of a dark signal, readout and spatial heterogeneity of CCD (charge-coupled device) matrix elements. In order to reduce noise effect it is proposed to apply the Wiener filter for smoothing an image and its unambiguous identification and also enter a threshold according to brightness level. The paper contains a comparison of two algorithms for determination of coordinates in accordance with energy gravity center and contour. Sobel, Pruitt, Roberts, Laplacian Gaussian, Canni detectors have been used for determination of the test-object contour. The essence of the algorithm for determination of coordinates lies in search for an image contour in the form of a circle with its subsequent approximation and determination of the image center. An error calculation has been made while determining coordinates of a gravity center for test-objects of various diameters: 5, 10, 20, 30, 40, 50 pixels of a photodetector and also signalto-noise ratio values: 200, 100, 70, 20, 10. Signal-to-noise ratio has been calculated as a difference between maximum image intensity of the test-object and the background which is divided by mean-square deviation of the background. The accuracy for determination of coordinates has been improved by 0.5-1 order in case when there was an increase in a signal-to-noise ratio. Accuracy improvement due to increase of a diameter in a test-object is typical for large signal-to-noise ratios: 70 or more. The conducted investigations have made it possible to establish that the algorithm for determination of coordinates of the energy gravity center is more accurate in comparison with contour methods and requires less computing power (for the MatLab software package), which is related to discreteness while determining a contour.