Scientific Works of Vinnytsia National Technical University
https://works.vntu.edu.ua/index.php/works
<p>Scientific Works of Vinnytsia National Technical University (ISSN 2307-5392) is online quarterly peer-reviewed scientific journal on technical sciences. It is English version of the journal <strong>Praci Vinnytskogo Natsionalnogo Technichnogo Universitetu</strong> (ISSN 2307-5376).</p>Vinnytsia National Technical Universityen-USScientific Works of Vinnytsia National Technical University2307-5392ANALYSIS OF THE METHODS FOR THE DETERMINATION OF THE MINIMUM REFLECTION CHARACTERISTIC IN THE PROCESS OF THE SURFACE PLASMON RESONANCE
https://works.vntu.edu.ua/index.php/works/article/view/555
<p>The paper analyzed the most widely used methods for the determination of the reflection characteristic minimum in the process of the surface plasmon resonance and considers the impact of the refraction index change of the studied environment and its temperature on the accuracy of the measurements, performed by these methods, applying the numerical modeling. It is known that the accuracy of the minimum reflection characteristic determination greatly depends on the mathematical methods of its determination. The most widely used methods of the minimum reflection characteristic determination are the methods of the polynomial approximation, which depend on the form of the reflection characteristic, that influences the accuracy of the minimum determination. The developed alternative method of the center line provides smaller measurement error when the refraction indices change from 1.33 to 1.5 times as compared with the methods of the polynomial approximation for the area of the reflection characteristic with the angular range of 0.125 ang. deg. and almost 8.5 times for the angular range of 0.2 ang. deg, that proves the expediency of the new method application. The smallest absolute error is characteristic for the method of the center line for the area of the reflection characteristic of 0.4, that is connected directly with the number of points, comprising the area of the minimum determination. The method of the center line, used for the study of the temperature changes of the analyte also provides smaller absolute error of minimum determination as compared with the polynomial approximation and has smaller error values scattering in the range of the higher temperatures. As compared with the polynomial methods the center line method has higher accuracy of the determination of the reflection characteristic minimum, because it is less dependent on its asymmetry, which is connected with the flow of the physical processes on the surface of the surface of the plasmons excitation. The results of the numerical analysis, carried out, may be useful for the development of the algorithms of the direct measurements processing by measuring devices on the base of the surface plasmon resonance.</p>Hanna Dorozinska
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2020-04-022020-04-021ANALYTICAL STUDY OF THE IMPROVED MATHEMATICAL MODEL OF THE VIBRATION DRIVE FOR SOLID HOUSEHOLD WASTE ADDITIONAL COMPACTION IN THE DUST CART
https://works.vntu.edu.ua/index.php/works/article/view/559
<p>On the base of the analysis, carried out, of the numerical studies of the complete. improved mathematical model of the vibrational compaction of the solid waste in the dust cart , using the pressure pulse generator of the relay differential action and taking into account the density and relative humidity of the dehydrated and pre- compacted solid waste the simplified improved mathematical model was suggested . In the process of comparison of the results, obtained using the complete and simplified improved mathematical models of the vibrational additional compaction of the solid household waste in the dust cart , in particular, the degree of their compaction, the error was 4.35%, this value is acceptable for the realization of the previous design calculations of the basic parameters of the drive. For the analytical study of the simplified mathematical model the working cycle of the improved vibrational drive for the additional compaction of the solid household waste in the dust cart is presented by six basic phases, each of them is described by the corresponding system of the differential equations with the initial and boundary conditions. For the analytical study of the simplified, improved mathematical model of the vibrational drive for the additional compaction of the solid household waste in the dust cart such methods are used: solution of the system of ordinary linear differential equations, applying the Laplace transformation, linearization of the non-linearities, decomposition of the expression into the common fractions, solution of the incomplete cubic equation, applying Cardano formulas, computer simulation. Analytical study of the simplified mathematical model of the vibrational drive for the additional compaction of the solid household waste in the dust cart enabled to obtain the analytical interdependences of its basic parameters and dependences of the frequency and amplitude on the basic parameters of the given drive with the error not exceeding 5.34%, they can be used for the realization of the preliminary design calculations of its parameters as one of the components for the solution of the problem, dealing with the development of the scientific-engineering fundamentals of the design of the efficient tools of the machines for the collection and primary processing of the solid household waste.</p>Oleg Bereziuk
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2020-04-022020-04-021IMPACT OF THE FORM FACTOR OF THE ABRASIVE PARTICLES OF THE SOIL ON THE INTENSITY OF THE TILLING MACHINES TOOLS WEAR
https://works.vntu.edu.ua/index.php/works/article/view/560
<p>Abrasive wear is one of the most common types of wear, about 50% of all machine parts failures fall on this type of wear. Study of the regularities of the abrasive wear process and search of the methods how to avoid the negative consequences is very important problem. In agricultural production working tools directly contacting with the soil undergo extensive abrasive wear. In the process of the operation of the tilling and seeding machines tools with the soil the wear of the surface occurs as a result of the interaction with the minerals, hardness of which is higher that the hardness of the metal. The form of the abrasive particles greatly influences the mechanism and intensity of the abrasive wear of the tilling and seeding machines tools.</p> <p>The aim of the given study is the determination of the form factor and soil abrasion of the abrasive particles of soils in Ukraine as well as the changes of the form coefficient of the abrasive particles as a result of the interaction with working tools of the tilling and seeding machines .</p> <p>Study of the form of the abrasive particles was carried out at all the type of soil in Ukraine.</p> <p>As a result of the research, carried out, it was determined that the form factor of the soil abrasive particles in Ukraine is within the limits of 78.9...487.65. Form factor of the abrasive particles for large fractions of the abrasive material is smaller than for small fractions. The value of the form factor of the abrasive particles in the tilling layer is less by 11.43...47.71% as compared with the abrasive particles in the raw layer. The regularity of the considerable decrease of the form factor of the abrasive particles of large fractions as compared with small abrasive caused by the interaction with the tools of tilling and seeding machines is observed. Wear capacity of the abrasive particles increases with the increase of the form factor. Direct dependence between the decrease of the wear capacity of the soil and decrease of the form factor of the abrasive particles is not observed due to the complexity of the structure and self organization of the soil environment.</p>Konstiantyn Borak
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2020-04-022020-04-021EXPERIMENTAL STUDIES OF THE ADAPTIVE HUDRAULIC SYSTEM ON THE BASE OF THE DISTRIBUTION VALVE WITH PROPORTIONAL ELECTROHYDRAULIC CONTROL
https://works.vntu.edu.ua/index.php/works/article/view/561
<p><em>Stable trend of the development of the hydraulic systems of mobile operation machines is the transition to the application of the regulated pumps and hydraulic devices with the proportional electric hydraulic control. In such hydraulic systems the correspondence of pumps capacity to the flow volume, consumed by the hydraulic motors as well as proportionality of the pressure value in the hydraulic system to the loading on the hydraulic motor or the most loaded of the several hydraulic motors is provided.</em></p> <p><em>Mobile machines equipped with such hydraulic systems can efficiently operate with wide range of the changeable working tools, providing high quality of the work and loading of the machines during a year. Besides, the proportional control in the hydraulic systems of this type provides high accuracy of the operation execution and greatly improves the working conditions of the operators.</em></p> <p><em>The paper considers the adaptive hydraulic system on the base of the distribution valve with proportional electrohydraulic control. Experimental stand for testing the adaptive hydraulic system was constructed. The hydraulic diagram of the distribution valve and the construction of the operation unit is presented. The distribution valve provides the possibility of the remote proportional electromagnetic control of the flow from the controller with the possibility of the stabilization of the hydraulic motors motion speed. Adaptive hydraulic system provides the possibility of the coordination of the hydraulic motors motion speed. The metrologic characteristic of the stand is given , which enables to control the value of the pressure in the hydraulic system, current and voltage values in the control lines, number of rotations of the hydraulic motor and registrate the dependences of the pressure values in the hydraulic system on the time if load changes. It was determined that the error of the flow value stabilization across the distribution valve does not exceed 6.8 %, in the studied range of the load change and the value of the flow changes proportionally according to the signal, sent from the controller. Regulation time in the hydraulic system on the base of the developed distribution valve did not exceed </em> <em> sec in the range of the pressure change </em> <em> МPа and the output of the pump </em> <em> m<sup>3</sup>/sec. </em></p>Volodymyr PylavetsArtem TovkachLeonid KozlovYurii BurenikovOlexandre Kravchuk
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2020-04-022020-04-021WORLD TRENDS OF THE REDUCTION OF THE MUNICIPAL WASTE LANDFILLS NUMBER ON THE EXAMPLE OF THE USA
https://works.vntu.edu.ua/index.php/works/article/view/556
<p>Over the last years the total area of the municipal solid waste landfills and waste dumping grounds has considerably increased, many of these landfills and waste dumping grounds are overloaded, as a result norms of ecological safety are violated and the landfills become the objects of the intensive ecological loading that may lead to the contamination of the environment with harmful substances: heavy metals, microorganisms (colibacilli, streptococci, staphylococci and ascarids), toxic filtrate, landfill gas, etc. The urgent scientific-engineering problem is the determination of the regressive dependences, which describe the dynamics of the number of municipal waste landfills decrease. The aim of the research is the determination of the regressive dependences, which describe the dynamics of the number of the municipal waste landfills decrease. In the process of the research the method of the regressive analysis of the result of the single factor experiments and other pair dependences with the selection of the best type of the function from the sixteen most widely spread variants by the criterion of the maximum value of the correlation factor was used. The regression was performed on the base of the linearized transforms, which enable to reduce the non-linear dependence to the linear one. Determination of the coefficients of the regression equations was carried out, applying the method of least squares, by means of the developed program "RegAnaliz", the program is protected by the certificate of the state registration of the rights to the copyright object. Adequate regression dependences, describing the dynamics of the number of municipal waste landfills decrease are obtained, they can be used for the determination of the necessary number of the dust-carts for the collection and transport of the solid household waste and machines needed for the execution of the technological operations of the compaction on the map of the waste dumping ground. Graphic dependences, describing the dynamics of the number of the municipal waste landfills decrease and allow to illustrate this dynamics and show the sufficient coincidence of the theoretical results with the actual data are constructed.</p>Оleg BereziukVolodymyr KraevskyiLudmila Bereziuk
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2020-04-022020-04-021ASSESSMENT OF THE IMPACT OF THE CONDITIONS OF THE DISK MICROSAMPLE FIXATION ON THE PUNCH TEST DIAGRAM, TAKING INTO ACCOUNT THE FRACTURE PROCESS
https://works.vntu.edu.ua/index.php/works/article/view/557
<p>One of the key parameters, used for the current control of the equipment state to provide its reliable operation is mechanical characteristics of the construction materials, in particular, strength characteristics. The most correct method of their determination is distractive test for uni-axial tension of the samples, manufactured from the investigated materials. The cutting of a certain volume of the material, needed for the fabrication of the sample can be critical for the carrying capacity of the construction. That is why, the indirect methods of the mechanical characteristics determination are developed to minimize the volume of the material, used for samples manufacture. Small punch test can be refereed to these methods. As this method is not standardized, the conditions of the tests are chosen by the researchers at their discretion. The given research considers the impact of the selection of one of the parameters, namely, the clamping force, on the results of the study. Steel 45 was chosen as the model material. Numerical modeling was carried out without taking into account and taking into account sample clamping force, equaled 5, 7.5 and 10 kN. The value of the von Mises equivalent stress in the clamped zone of the sample did not exceed 264 MPa. To take into account the fracture process Gurson – Tvergaard – Needleman (GTN) model was used. The problems was simulated in the dynamic formulation, using the explicit integration scheme. Diagrams of disk microsample punching in the coordinates «load» – «deflection» at the given conditions of fixing is given. By the results of the study it was determined that the force of sample clamping does not influence greatly the punching diagram, that is why, to decrease the time, needed for the numerical calculations it can be neglected. In the course of the experimental tests it was recommended to select the clamping force of the sample so that to avoid plastic deformation of the sample in the area of the clamping.</p>Roman Kravchuk
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2020-04-022020-04-021TECHNOLOGICAL PARAMETERS OF THE RADIATION-RESISTANT CONCRETE PRODUCTION
https://works.vntu.edu.ua/index.php/works/article/view/558
<p>The paper contains the materials of the studies which prove that the construction sphere in the 21<sup>st</sup> century requires the application of new efficient, low cost construction materials specially designed for the protection against hazardous ecological factors. Methods of designing the compositions of concretes and technology of the special-purpose construction materials production is considered. The importance of studying the problems, dealing with the necessity of the development of the heavy concretes, able to shield the penetrating radiation is stated. The available developments in the sphere of the construction materials science are considered, the peculiarities of the technological parameters of obtaining special-purpose concretes on the base of the mineral binders are allocated. It is noted that the application of various by physical-chemical characteristics concrete aggregates on the base of mineral binders, allows to obtain composite materials, having wide range of operation properties. Experimental studies proved the possibility to regulate the construction engineering and electric physical properties of fine grain concretes using small-size metal aggregates, obtained from the machining waste. The possibility to regulate the technological parameters of the metal- saturated concretes for the obtaining of the composite material with the radiation-protection properties is underlined. It was determined that during the addition of the small-size metal aggregate to 35 % of the pts in the structure of the flow mixtures micro compaction of the structure takes place and the increase of the water demand of the forming solution is observed . As a result of using the technology of the mechanical compaction of the structure of the dispersed-filled products, sample-models of the radiation-proof coating with the average density of up to 2910 kg/m<sup>3 </sup> are obtained. Application of the technology of the artificial synthesis of the matrix metal-saturated dense structure of the dispersed -filled conglomerate with the large area of the internal surfaces of the phases separation will provide the products made of special concrete the ability to weaken ionizing radiation fluxes in the body of the barrier screen. The possibility to regulate radiation-protection properties of the concretes by changing formulation -technological parameters of the composite material production is substantiated. It is shown that due to physical-chemical processes of the disperse-filled structures formation the volumetric electroconducting matrix is formed in the body of the fine-grain metal-saturated concrete, each component of the matrix differs by its electrical physical properties. According to the laws of quantum physics ionizing electromagnetic radiation possesses simultaneously wave and corpuscular properties, the absorption of the penetrating radioactive radiation in the structure of the material occurs due to the repeated reflections and diffusions of the radiation flux by the surface of the metal and the intensity of electromagnetic waves will decrease by the counteraction field, excited in the volume of the electroconducting matrix. Regulation of the formulation -technological parameters of the fine grain concrete by filling matrix mineral structures with the reaction able metal powder and formation of the iron-containing hydrosilicates with elevated concentration of the constitutional water will identify the obtained composition material with the special multilayer metal-water shields.</p>Olexander KhrystychMykhailo LemeshevDmytro Cherepakha
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2020-04-022020-04-021IMPROVEMENT OF THE POWER SUPPLY SYSTEM RELIABILITY BY MEANS OF UNMANNED AERIAL VEHICLES
https://works.vntu.edu.ua/index.php/works/article/view/563
<p>Energy system of Ukraine comprises the distributed electric grids of complex configuration, the generating facilities and consumers of electric energy are located at large distances. Numerous objects of energy branch require constant monitoring. However, the upgrading of the equipment takes place at a slow rate that leads to the increase of the wear. Depreciation of equipment in the power supply system of Ukraine affects the reliability of power supply and quality indicators. Ageing and wear of the equipment results in the increase of accidents and emergencies. As it is impossible to completely replace the outdated equipment simultaneously, the concept of gradual replacement is adopted. In such conditions, maintaining of the operating condition of the equipment is ensured by the routine maintenance, performed by the operating crew. But the quantity of the staff constantly decreases, that is why, to maintain the operating conditions of the system new technologies should be developed and introduced which enable to detect the exact location of the fault and its character. The dependence of the system reliability on the frequency of riding inspections is shown. To achieve standard reliability values, the frequency of inspections should be a function of the wear of the equipment, and not a constant. Calculations are presented, showing the need to increase inspections to maintain the reliability of the system at the proper level. The increase in the frequency of inspections leads to the increase in the cost of servicing the power system, and as a result, the increase in the cost of electric energy. The authors suggest using unmanned aerial vehicles for the inspections, determination of the location of the accident. It is shown that the use of unmanned aerial vehicles will increase the number and quality of inspections, thereby increasing the reliability of the electric power system and, accordingly, reducing the cost of electric energy transportation.</p>Oleg GribIgor KarpaliukSergey ShvetsNatalia Zaharenko
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2020-04-022020-04-021