METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky <p class="rteleft">Subjects: Subjects of the “Quality Control Tools and Techniques” journal include the following sections:<br>- methods and means of non-destructive testing;<br>- measurement of physical and chemical parameters of substances;<br>- methods and devices for measuring flows of liquid and gaseous phases;<br>- methods and means of controlling technological parameters,</p> <p class="rteleft">- mathematical modelling for the undestroyed control problems.</p> <p>The “ Quality Control Tools and Techniques ” journal publishes review and research articles that are dedicated to these subjects (but are not limited only by them).</p> en-US mmi@nung.edu.ua (Олійник А. П) Thu, 27 Jun 2019 00:00:00 +0300 OJS 3.1.2.4 http://blogs.law.harvard.edu/tech/rss 60 THE MAIN CHARACTERISTICS AND FEATURES OF THE LOW-FREQUENCY WAVE PROCESS IN THE STRETCHED PIPELINES http://mpky.nung.edu.ua/index.php/mpky/article/view/478 <p>The problem of determining the technical condition of various pipeline systems, ensuring their reliable аnd safe operation has recently become the subject of geopolitics. In this situation, constant monitoring of their technical condition is essential for the maintenance of pipelines. However, it is technically difficult to monitor the technical state of pipelines by conventional methods of non-destructive testing (NDT).</p> <p>An analysis of the essence of the wave process in diagnosing the technical condition of long pipelines by low-frequency ultrasound directed waves is performed. The types of modes of directed waves and peculiarities of the wave process in the solid medium of the pipeline are given. Dispersed diagrams of &nbsp;ound velocities for different modes of directed waves are considered, on the basis of which their main features are formulated in the diagnosis of the technical state of extended pipelines. The analysis of the wave process in the long pipeline from the position of the acoustic location of its solid medium by low-frequency directional waves is made, the model of the active localization system is developed in diagnosing the technical state of the pipeline, the principles of excitation and displacement of the particles of the medium of the pipe wall are considered in the distribution of longitudinal, twisted and bending mods of low-frequency ultrasonic directed waves.</p> <p>When choosing the frequency and mode of the directed wave to diagnose the technical state of long pipes, it is necessary to take into account that the directed wave is the result of the interaction of the vibrations generated by the transducers with the pipe surface. A significant factor determining the efficiency of energy transfer from the antenna to the body of the drainage pipeline is the harmonization of the internal resistance of the converter and the load due to the static force of pressing the piezoelectric transducers to the pipe surface. When creating systems of low-frequency ultrasonic diagnostics of long-distance pipelines directed waves it is necessary to take into account the main features of the wave process, which has a complicated mechanism of propagation over the thickness of the pipe wall.</p> O. G. Bondarenko Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/478 Thu, 27 Jun 2019 00:00:00 +0300 THE ELECTRIC DRIVE PUMPING UNITS STEADY OPERATING MODES OPTIMIZATION BY THE MODES RELIABILITY CRITERIAS http://mpky.nung.edu.ua/index.php/mpky/article/view/479 <p>According to the research results, the target functions of the task of optimizing the functioning of the units according to the criteria of the regime reliability, depending on the flow of the working fluid were synthesized, which made it possible to research the influence of the regime on the reliability of operation of electric and hydraulic subsystems of the pump unit. The extreme weight of local target functions of regime reliability of electric motor and the centrifugal pump in various (especially low-flow rate) operating modes are determined. It is proposed to optimize the operating modes of&nbsp; pumping units of oil pumping station with the simultaneous use of the reliability criteria of electric drive and centrifugal pump. . It was established that the maximum values of reliability of electric drive and centrifugal pump are achieved at different values of the load, which requires the involvement of multi-criteria optimization methods. The problem of optimization of the established modes of the pump unit in the multicriteria setting, taking into account the technological limitations of its subsystems was formalized. The analysis of modern methods of solving the problem of multicriteria optimization of the steady modes of operation of pump units is carried out. The method of solving the multicriterion optimization problem is substantiated, which fully takes into account the influence of operation mode on the reliability of electric and hydraulic subsystems of pumping unit. It is revealed that the most appropriate method for solving this problem is the method of approaching an ideal (utopian) point in the criteria space. With this method, the desired ratio of criteria at the optimum point is the best. The value of the "agreed optimum" of liquid flow has been determined in order to choose the optimum for the reliability of operation mode of the pumping unit of oil pumping station.</p> I. I. Yaremak Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/479 Thu, 27 Jun 2019 00:00:00 +0300 IMPROVING THE CAPILLARY METHOD OF NON-DESTRUCTIVE TESTING http://mpky.nung.edu.ua/index.php/mpky/article/view/484 <p>The history of capillary control began in the 40s of the last century for the needs of the aerospace industry.&nbsp;Currently, the cost of quality control in the aerospace industry is up to 12 - 18% of the cost of products. Similar&nbsp;amounts of expenses in the nuclear and defense industries are not lagging behind other industries. For example, for&nbsp;the control of welded joints of oil and gas pipelines of large diameter and considerable length, the labor costs for&nbsp;inspection reach 10% of the total labor costs. Capillary quality control method is based on the ability of indicator&nbsp;liquids (penetrants) to penetrate into the cavities of surface defects (discontinuities). Over the 70 years of its existence,&nbsp;the capillary method of control has not undergone fundamental changes, and its principles have remained unchanged.&nbsp;In international practice, the abbreviated designation of types of non-destructive testing (AWS) is adopted, and the&nbsp;control with the use of penetrating liquid denoted RT. This method is applicable to the detection of all types of surface<br>dead-end and through defects, such as cracks, delamination, leaks, in products made from any non-porous materials,&nbsp;including glass, ceramics, plastics and other non-metallic materials. The analysis of the capillary method of nondestructive&nbsp;testing of the surface of a solid body is carried out, the possibilities and ways of its improvement are&nbsp;indicated. The method of the capillary method of non-destructive testing of a solid surface, the physics of the method&nbsp;and its implementation are considered in detail. It is shown that the wetting ability and spreading are important&nbsp;characteristics of capillary control fluids; therefore, they must be evaluated and analyzed when developing new ones,&nbsp;choosing or comparing known capillary flaw detection materials. The possibility of using the Rebinder effect to&nbsp;improve the capillary method of non-destructive testing of a solid surface has been proved. A refined method of&nbsp;capillary defectoscopy is proposed by taking into account the wetting ability, density, viscosity and evaporation of a&nbsp;liquid, which makes it possible to make an optimal choice of liquid to ensure high efficiency of surface (capillary)<br>control. An improved method for assessing the wetting ability of liquids is proposed, which makes it possible to&nbsp;evaluate the wetting ability of liquids by the size of the spreading spot of their droplets, taking into account the&nbsp;influence of density, viscosity and evaporation of liquids intended for capillary flaw detection (penetrants).</p> V. V. Lopatin Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/484 Thu, 27 Jun 2019 00:00:00 +0300 RESEARCH OF STATIONARY PLANE FIELDS BY MEANS OF COMPLEX POTENTIAL http://mpky.nung.edu.ua/index.php/mpky/article/view/473 <p>Some of the most frequently encountered and generic types of plane vector fields with singular points at the origin of the coordinate system have been studied using <a href="https://www.multitran.com/m.exe?s=complex%20variable%20theory&amp;l1=1&amp;l2=2">complex variable theory</a> methods combined with complex potential methods and field theory methods. The basic concepts of field theory and vector analysis, which are used to study vector fields and the main numerical characteristics of these fields, have been considered.</p> <p>The study of the most frequently encountered vector fields with singular points of four types, namely the generator, the <a href="https://www.multitran.ru/c/m.exe?t=1663714_1_2&amp;s1=%E2%E8%F5%F0%FC">vortical point</a>, the eddy source, the dipole, have been conducted. The application of the complex potential for finding the main characteristics of the vector fields of the considered types, namely their divergence and rotor, has been shown. Equipotential lines and streamlines of the considered vector fields have been obtained and graphically constructed using the method of complex potential. Studied using the vector analysis methods and the methods of the theory of complex variable functions (complex potential) characteristics of vector fields can be used for mathematical modeling of various problems, arising during the study of layers, namely soil and water reservoir filtration problems, as well as in studying the flow of fluid or gas in layers problems.</p> <p>The developed and considered mathematical models of flat vector fields and the found numerical characteristics of these fields can be used to solve other problems of the oil and gas complex, which require studies of the flow of liquids or gases in gas- or oil-bearing beds.</p> V. P. Nisonskii, Yu. V Kornuta, I. M-B. Katamai Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/473 Thu, 27 Jun 2019 00:00:00 +0300 ALGORITHMIC AND SOFTWARE OF THE COMPUTER SYSTEM FOR THE SELECTION OF OPTIMAL QUANTITY OF NATURAL GAS OPERATING PARALLEL WORKERS http://mpky.nung.edu.ua/index.php/mpky/article/view/474 <p>In connection with reduction of volumes of transporting of gas through the gas-transport system of Ukraine the issue of the day is the rational loading of the compressor stations taking into account the technical state of gascompressor units. The mathematical model was developed in the article on principles of fuzzy logic, that gave an opportunity to define the technical state of gascompressor units that are working in parallel taking into account such parameters as the productivity of supercharger, expense of fuel gas, pressure and temperature on an entrance, pressure and temperature on the exit of centrifugal supercharger, temperature of products of combustion on an exit from the turbine of LP, frequency of rotation of shaft of the supercharger, temperature and pressure of environment, vibrospeed and vibroacceleration, speed of accumulation product of triggering in agile olive, concentration oxide nitrogen and carbon in exhaust-gas.</p> <p>The expense of fuel gas, that is measured by facilities of regular automation, depends on many factors such as atmospheric pressure, ambient temperature, physical and chemical properties of fuel gas, technical state and type of turbo-engine. All that grounds to consider the expense of fuel gas an unclear value. Experimental researches on the base of Bohorodchany compressor station showed, that unclear value the "expense of fuel gas" has Gauss function of belonging. Therefore the task of choice of optimal amount of aggregates working in parallel is formalized as a task of integer of the linear programming, the criterion of optimality in that is a cost of fuel gas that consumes the compressor station taking into account the technical state of gascompressor units and unclearness of expense of fuel gas.</p> <p>Efficiency of the worked out method is confirmed by calculations that are based on industrial data received &nbsp;during exploitation of Bohorodchany compressor station.</p> M. I. Gorbijchuk, O. T. Bila, B. V. Pashkovskyi, N. T. Lazoriv Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/474 Thu, 27 Jun 2019 00:00:00 +0300 ANALYSIS OF ENERGY FLOWS IN POWER SUPPLY SYSTEMS WITH NON-LINEAR LOAD http://mpky.nung.edu.ua/index.php/mpky/article/view/472 <p>The problem of the non-sinusoidal modes analysis of the power supply system with non-linear elements and their influence on the efficiency of the power transmission are considered. It is carried out numerical analysis of electric energy flows for three phase power supply system with sinusoidal electromotive force source, linear active load and non-linear elements (diodes). Power transfer is considered as distribution of the primary power flow from source. The part of this flow is converted by non-linear elements and return into the network like secondary power stream of zero sequence and high harmonics which is consumed by resistance elements and causes additional power losses. As a result transporting efficiency and power factor are reduced and energy quality becomes worse. In order to improve the quality of electricity, it is proposed to normalize the relative value of the reactive power of distortion for non-linear electric collectors and to oblige manufacturers of electrical products to complete them with filters of higher harmonics. With the purpose of correct selection of the type and power of compensating devices and monitoring the parameters of the electric network mode, it is proposed to expand the functionality of electronic meters by dividing the reactive power into two components - shear power and distortion power, and for the objective analysis of energy flows, it is proposed to standardize the reactive power of distortion. It is shown that in such system current in neutral line increases due to overlaying of zero sequence harmonics currents. This should be taking into account during neutral line cross-section choice and power losses calculation.</p> B. L. Grabchuk, Yu. F. Romaniuk Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/472 Thu, 27 Jun 2019 00:00:00 +0300 CALCULATION OF CURRENT LOADING OF THREE-PHASE BRIDGE RADIATION IN NON-SUPERMEAL MODES UNDER THE FILTRATION AVAILABILITY http://mpky.nung.edu.ua/index.php/mpky/article/view/481 <p>The curves of the rectified voltage of the non-ventilated modes of the three-phase bridge rectifier circuit have in their composition a number of non-canonical higher harmonics, which results in significant pulsations of the load current. Hence the problem of choosing the optimal composition of filters in order to prove the load current pulsation coefficient to allowable values. The analysis of the current state of the problem is carried out by studying the latest publications.</p> <p>The analytical expressions and forms of load current curves are obtained based on the results of mathematical modeling of the resonant and inductive filters higher harmonics influence&nbsp;&nbsp;&nbsp; on the outputs and rectifier loads, respectively, on the leads and in the rectifier load cell. The value of the current ripple coefficient in the load cell for the individual cases of the non-ventilated mode of the three-phase bridge rectifier is calculated. The curves of the currents given in this article are valid for those forms of rectified voltage that arises in non-blunt modes of the three-phase bridge rectifier scheme, and can be obtained under the condition of a known composition of higher harmonics of the output voltage of the rectifier. It is shown that the establishment of a resonance filter at the frequency of the largest harmonic significantly reduces the current pulsation coefficient in the load cell.</p> <p>In the case of a real resonance filter at the output of the rectifier in the current of the load circuit there will be a harmonic, which will proceed under the action of a voltage drop on the active resistance of the filter. However, its effect will be negligible, since the active resistance of the filters is usually small. The level of harmonic components in the load current will also diminish somewhat as a result of the branching of a certain value of these currents through the branches of the resonant filters.</p> <p>The proposed method allows to calculate the current in the recirculation load cell in non-ventilated modes, taking into account a certain composition of resonant parallel and inductive serial filters to achieve the desired level of current pulsations.</p> M. B. Sabat, N. G. Maltseva, M. Y. Oliinyk, V. G. Fedishin Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/481 Thu, 27 Jun 2019 00:00:00 +0300 CLASSIFICATION OF WIRELESS SPECIALIZED COMPUTER NETWORKS FOR THE OBJECTS LOCATION MONITORING http://mpky.nung.edu.ua/index.php/mpky/article/view/475 <p>At present, it is possible to achieve the desired level of management of any enterprise only if there is complete and up-to-date source information about the current state of affairs in this enterprise. Growing size of an enterprise complicates the collection of necessary information and its processing. The speed and completeness of data collection is also influenced by many other factors associated with the specifics of specific enterprises. In particular, oil and gas companies have a large number of objects located at large distances from each other (including in remote and hard-toreach areas). In addition, these enterprises operate a variety of equipment and uses a large range of different matetechnical values. Quite often, for certain managerial needs, equipment and material and technical values can be moved within a single unit located in a large area or between units of one oil and gas undertaking. In connection with the aforementioned present, the enterprises of the oil and gas complex require the introduction of modern effective systems for collecting information on available material and technical values and their location at a certain point in time. In order to solve this problem, an analysis of modern wireless specialized digital networks was carried out and identified from them, which can be used at enterprises of the oil and gas complex for the monitoring of the location of the objects. Also, the basic characteristics of wireless specialized digital networks (which can be used for systems for monitoring the location of objects), by which they can be classified, are also established. A classification of wireless specialty digital networks (which can be used for objects monitoring systems) is created, which allows the specialists of control and measurement equipment and automation services to select the most appropriate wireless digital network for monitoring the location objects of oil and gas enterprises.</p> S. M. Babchuk Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/475 Thu, 27 Jun 2019 00:00:00 +0300 COMPARATING ANALYSIS OF COORDINATE SEARCH METHODS EFFICIENCY FOR THE OPTIMAL SOLAR PANEL POSITION FINDING http://mpky.nung.edu.ua/index.php/mpky/article/view/480 <p class="m2695684017877154926m-9055650787395451574gmail-western" style="margin: 0cm; margin-bottom: .0001pt; text-align: justify; text-indent: 21.25pt;"><span lang="UK" style="font-size: 10.0pt;">The work is devoted to the investigation of the effectiveness of the coordinate search methods for solving the problem of finding the position of the solar panels, in which the greatest power of the produced current is achieved. The existing solutions in the market of sun surveillance systems (solar trackers) are analyzed. The advantages and disadvantages of such systems are presented in comparison with fixed panels. It is proposed to improve the hardware and software for research of the solar panels efficiency, developed by the authors and highlighted in the previous works, by integrating the program realization of the algorithm of coordinate search of the maximum power of solar panels into the existing. For this purpose, the efficiency of three algorithms for coordinate search of the maximum, namely, the method of coordinate ascending, the Huck-Jeeves method and the Rosenbrock method, was studied in three parameters. Experiments were carried out on data obtained both experimentally using the lab stand for solar panel efficiency research, and by generation using mathematical model of the solar panel efficiency dependance on the angle of radiation, described in previous works. TThe results of experiments are analyzed, which showed a fundamental difference between the work of coordinatewise search algorithms on a mathematical model and experimental data. The main indicators of the efficiency of algorithms are substantiated on the basis of the meteorological conditions in which the measurement was carried out for the formation of experimental data. Conclusions are drawn regarding the efficiency of using these coordinate-based search methods for solving the problem of finding the optimal position of solar panels. Further prospects for research on this topic and the possibility of using coordinate-wise search methods in software of solar panels with a biaxial orientation on the position of the Sun are given.</span></p> M. O. Slabinoga, N.B. Klochko, O. S. Krynytskyi , Yu. M. Kuchirka Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/480 Thu, 27 Jun 2019 00:00:00 +0300 THE MINERAL WATER TESTS METHODS METROLOGICAL ANALYSIS AND THE PROPOSALS ON THEIR IMPLEMENTATION IN UKRAINE http://mpky.nung.edu.ua/index.php/mpky/article/view/483 <p><em>In connection with the necessity to unify the procedures and requirements applicable to goods and services, first of all, with regard to conformity assessment, in order to eliminate technical barriers to trade, a list of methods for testing mineral waters has been analyzed, according to which their assessment of conformity and determination of individual safety and quality indicators. The paper analyzes the metrological characteristics of the methods approved in the form of international, national standards, standards adopted before 1992, test methods for assessing their suitability for implementation not only in the testing, but also in the production laboratories. According to the results of the analysis of 42 indicators of the measurement methodology, which are specified in DSTU 878-93 (regulatory document on packaged mineral water) and GSTU 42.10-02-96 (normative document on medical waters used in sanatorium practice), 13 indicators , which are mandatory, as they are specified in the relevant normative documents, are not valid. According to the results of the analysis of the metrological characteristics of the methods of testing the indicators of safety and quality of mineral waters, a list of methods of tests of mineral waters for the period 2019-2021 has been developed, which includes national standards certified in Ukraine methodology and GOST for drinking water, in particular, on sulfates, ammonium and iron . However, the effect of these GOST on the testing of drinking water after 2021 will be abolished, and they should also be replaced either internationally or to develop national standards. In selecting the methods of testing mineral waters, two aspects were taken into account: the conformity of metrological characteristics of the methods during the assessment of the conformity of mineral waters, taking into account the features of the composition of the mineral water itself (applicability of the method for both low and high mineral waters), and the economic feasibility of testing for the appropriate method (due to the impossibility of many testing and production laboratories to use high-value equipment). In order to provide modern standards (international and national) of packaged mineral water producers and test laboratories conducting an assessment of the conformity of mineral waters, a list of methods for testing mineral waters, which is to be developed in Ukraine for the replacement of interstate GOST or methods, the metrological characteristics of which do not correspond to the current one, is proposed. in Ukraine the rules of legal metrology, and to give them the status of national standards (for the definition of Pseudomonas spit, sulfates, ammonium, bro copper and iodide). This will enable Ukrainian producers of packaged mineral water to optimize production costs for the production of Ukrainian products and successfully expand its share in the foreign market.</em></p> A. Yu. Kysylevska, K. D. Babov, I. V. Prokopovich, Ch. A Koeva Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/483 Thu, 27 Jun 2019 00:00:00 +0300 MODELING OF THE PROCESS OF POURING THE PRODUCT THROUGH THE RECEIVER-DISTRIBUTING DEVICE VST http://mpky.nung.edu.ua/index.php/mpky/article/view/476 <p>Preserving quality and quantity of a product is an important task during the operation of tank farms.&nbsp; This requires maximum sealing of all processes of pouring, discharging and storing.&nbsp; Tanks have the largest share of evaporation losses throughout the course of the oil flow from fishing to refineries, at factories and petroleum product pipelines from factories to consumers.&nbsp; The process of storage of oil and petroleum products is combined with other technological operations (desalting of oil, heating, dehydration, mixing, etc.).</p> <p>&nbsp;One of the most important methods of saving fuel and energy resources, which occupy a leading place in the development of the economy, is the fight against oil products losses.&nbsp; The issue of product losses due to the lack of equipment and the durability of its use is important.&nbsp; One of them is a receiving and distributing device, which is installed in vertical steel tanks.</p> <p>&nbsp;To compare two of the most common variants of the execution of the disengagement body of the (ПРУ що це таке), a simulation of the process of pouring the product into the reservoir was performed using the Ansys 19.1 program.&nbsp; This made it possible visually to see how the receiving and distributing device works and what its efficiency can depend on.&nbsp; From the model of pressure distribution to the wall of the case (ПРУ) it is evident that when smoothly turning the housing, the pressure is distributed more evenly, due to which the load on the corner and the entrance to the receiver-distributing device in the wall of the tank will be less than when turning with the insert.</p> <p>In this article&nbsp;an analysis of the possibility of improving the outdated technologies and the use of the latest in the storage of petroleum products&nbsp;is&nbsp;given. The use of a receiving and dispensing device can significantly increase the inter-cleaning period during the operation of the reservoir, as well as reduce the amount of work when cleaning the reservoir. This will reduce the level of dead remains, improvement&nbsp;the service life of the lower belt and the bottoms of vertical steel tanks, by reducing the zone of corrosive activity of the bottom sediment.</p> O. T. Chernova Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/476 Thu, 27 Jun 2019 00:00:00 +0300 ABOUT OF THE DYNAMICS OF FORCED OSCILLATIONS IN NONLINEAR SYSTEMS http://mpky.nung.edu.ua/index.php/mpky/article/view/482 <p>The article discusses the issues of determining the effectiveness indicators of an electromagnetic vibration exciter in a dynamic mode of operation. It is established that this system is whole system of electrical and mechanical circuits. In this case, the mechanical part operates in the mode of forced vibrations. The oscillation parameters of the system, such as amplitude, frequency, and phase, largely depend on the parameters of the system load. For the analysis of this system, differential equations describing an electromagnetic vibration exciter have been compiled. For this purpose, the dependence L(x) of the inductance on the displacement is used. The dynamic modes of one of the ways of asynchronous excitation of an electromagnetic vibration exciter are investigated. The accuracy analysis and the evaluation of the results were performed by the Fisher criterion for the regression model. To analysis of transients in the electromagnetic vibration exciter, were used the software packages WinFact and MatLab to simulate and optimize dynamic systems. It is established that the system, depending on the initial conditions in the simulation, goes into one of two very different modes. In this case, the initial zero conditions switch the system into a “cyclic” mode, and in other, non-zero conditions, the system goes into an approximate cyclic mode, characterized by a higher speed of movement of the anchor. The parameters of the steady state cyclic movement are determined by the method of harmonic balance.</p> <p>The obtained results allow us to describe autoparametric oscillations of the electric equivalent circuit. It has been established that the compilation of harmonic balance equations corresponding to a linear system helps simplify the solution of the task of determining the dynamics of forced oscillations. The expressions for determining the tractive force and the current flowing through the circuit are obtained, the wavelet spectra of vibration are constructed using the MatLab software package. As a result, for the mechanical part of a nonlinear system, in fact, it is necessary to solve only harmonic balance equation. The results show that this theoretical model allows a more qualitative and accurate assessment of the observed phenomenon. Based on this, the asymptotic conditions for solving the harmonic balance equations of a nonlinear system are determined. The expressions for the electromagnetic force acting on the anchor are obtained, the conditions for the harmonic balance of the mechanical part of the system are determined. The expressions obtained allow us to construct the amplitude-frequency characteristics of the electromagnetic vibration exciter. In conclusion, not only qualitative, but also quantitative estimates of the observed phenomena were obtained. It has been established that mechanical oscillations of a nonlinear system are insensitive to changes in the supply network and practically have a large amplitude with a constant frequency.</p> A. N. Qurbanov, I. Z. Sardarova Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/482 Sun, 27 Oct 2019 00:00:00 +0300 THE MATHEMATICAL MODELLING METHODS APPLYING TO ESTIMATE THE PIPELINES TECHNICAL STATE AND ENVIRONMENT SITUATION http://mpky.nung.edu.ua/index.php/mpky/article/view/477 <p>In the context of providing trouble-free operation of oil and gas pipelines and preventing possible negative impacts on the environment, the issues of constructing an integrated mathematical model for assessing the technical condition of pipelines and the impact of emergency situations on the state of the environment in the course of hydrocarbon leakage are considered. The model of the evaluation of the stress-strain state of the pipeline according to the data on the displacement of surface points for the above ground and underground sections is given by constructing the law of motion of the site by known displacements of a certain set of surface points using assumptions about the type of deformation of the sections and reproduction of the deformations and stresses tensors components &nbsp;&nbsp;on the basis of different models of deformed solid body.</p> <p>The specified model does not require information on the whole complex of forces and loads acting on the investigated object during operation. The flow model has been refined in a pipeline with a violation of its tightness by recording a special type of boundary conditions for a Navier-Stokes equation system in a two-dimensional formulation and developing an original method for its solution on the basis of the finite difference method. In the article the stability conditions of the proposed numerical schemes on basis of the spectral sign of stability are presented. In order to assess possible negative impacts on the environment, a model of propagation of matter at its leakage from the pipeline was developed by solving two-dimensional diffusion equations taking into account the variables and different types of boundary conditions that take into account the number of sources of pollution and their intensity. The results of computations based on computational algorithms implemented by these models and graphic material illustrating these calculations are presented, peculiarities of distribution of harmful substances in the environment near the pipeline are analyzed. Directions of further researches for successful practical realization of the offered models are established.</p> A. P. Oliinyk, G. V. Grigorchuk, R. M. Govdyak Copyright (c) 2019 METHODS AND DEVICES OF QUALITY CONTROL http://mpky.nung.edu.ua/index.php/mpky/article/view/477 Thu, 27 Jun 2019 00:00:00 +0300