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Документ Increasing the efficiency of the surface-mounted ultrasonic electromagnetic-acoustic transducer on account of the magnetic field source(Інститут електродинаміки НАН України, 2023) Suchkov, G. M.; Bolyukh, V. F.; Kocherga, A. I.; Mygushchenko, R. P.; Kropachek, O. Yu.Model studies were carried out using the COMSOL Multiphysics package, aimed at ensuring the forming of a permanent magnet magnetic field at a considerable distance to a ferromagnetic product from its pole, which is necessary to create efficient portable ultrasonic electromagnetic-acoustic transducers of thickness gauges and testing and diagnostic devices. It is theoretically shown and experimentally confirmed that for portable measuring ultrasonic devices it is expedient to set the height of the permanent magnet at about 60 mm and the cross section of the magnet pole 50x50 mm2. At the same time, with a gap between the magnet pole and the product of about 30 mm, the value of the normal component of the magnetic field induction near the surface of the object is about 0.3...0.4 T, which is sufficient for thickness gauging or diagnostics of ferromagnetic products using the ultrasonic pitch-and catch method.Документ Metrological study of the effect of temperature on the dissociation of acetic acid(Національний технічний університет "Харківський політехнічний інститут", 2023) Mygushchenko, R. P.; Volobuyev, M. M.; Asieieva, I. V.; Kropachek, O. Yu.; Baliev, V. M.This article is devoted to the study of the dissociation reaction of acetic acid at a temperature change in the range from room (20 °C) to 75 °C. In the course of research, the methods were considered, the classification of the considered methods was carried out, and the methodology of the experiments was formulated. The selected technique reflects the express measurement of the hydrogen pH indicator using a portable pH-meter. Experiments were carried out in laboratory conditions – Lincoln Park, Chicago, USA. Acetic acid with a concentration of 6 mol/l was chosen as the basis. By adding a distilled water, a base concentration of 1 mol/l was obtained. Nodal temperature points were selected for measurements (four points in the temperature range of 20 °C – 75 °C); five experimental samples of acetic acid (1 mol/l) were formed; the analysis of the measurement results at nodal points was carried out for the accuracy of the measurement results of five test samples of acetic acid using first- and second-order statistical moments (mathematical expectation and variance); accuracy characteristics of experimental data (instrumental and methodical errors) were estimated. Research samples (acetic acid samples) were brought to the nodal points with a positive temperature gradient using a steam bath. The measurement error estimate was determined by the accuracy class of the device and was 0.1%. The obtained pH values were converted to the number of hydrogen cations, followed by the determination of the degree of dissociation and the dissociation constant. These determinations were carried out under the condition of ensuring chemical equilibrium. The nature of the behavior of the degree and constant of dissociation when the temperature of the test samples changes is clearly non-linear. In the course of research, the main measurement errors were established, the main of which is the nonlinearity of the transformation. Quantitative values of nonlinearity errors were determined by the method of measurements with multiple observations using the Student's correction factor. The article provides conclusions based on the results of research and presents the prospects for temperature correction of pH-meters to eliminate the temperature component of the error of pH-meters.Документ Minimization of errors in discrete wavelet filtering of signals during ultrasonic measurements and testing(Національний науковий центр "Інститут метрології", 2021) Taranenko, Yu.; Mygushchenko, R. P.; Kropachek, O. Yu.; Suchkov, G. M.; Plesnetsov, Yu.Error minimizing methods for discrete wavelet filtering of ultrasonic meter signals are considered. For this purpose, special model signals containing various measuring pulses are generated. The psi function of the Daubechies 28 wavelet is used to generate the pulses. Noise is added to the generated pulses. A comparative analysis of the two filtering algorithms is performed. The first algorithm is to limit the amount of detail of the wavelet decomposition coefficients in relation to signal interference. The minimum value of the root mean square error of wavelet decomposition signal deviation which is restored at each level from the initial signal without noise is determined. The second algorithm uses a separate threshold for each level of wavelet decomposition to limit the magnitude of the detail coefficients that are proportional to the standard deviation. Like in the first algorithm, the task is to determine the level of wavelet decomposition at which the minimum standard error is achieved. A feature of both algorithms is an expanded base of discrete wavelets ‒ families of Biorthogonal, Coiflet, Daubechies, Discrete Meyer, Haar, Reverse Biorthogonal, Symlets (106 in total) and threshold functions garotte, garrote, greater, hard, less, soft (6 in total). The model function uses random variables in both algorithms, so the averaging base is used to obtain stable results. Given features of algorithm construction allowed to reveal efficiency of ultrasonic signal filtering on the first algorithm presented in the form of oscilloscopic images. The use of a separate threshold for limiting the number of detail coefficients for each level of discrete wavelet decomposition using the given wavelet base and threshold functions has reduced the filtering error.Документ Еlectromagnetic-acoustic transducers for ultrasonic measurements, control and diagnostic of metal products(Національний науковий центр "Інститут метрології", 2019) Salam, Bussi; Suchkov, G. M.; Mygushchenko, R. P.; Kropachek, O. Yu.; Plesnetsov, S. Yu.An effective type of ultrasonic method is the electromagnetic-acoustic method, especially in determining the quality of ferromagnetic products. The main factor determining the efficiency of using electromagnetic-acoustic transducers is the magnitude of the induction of a polarizing magnetic field, which is determined by the source. The studies carried out in the framework of this activity were aimed at solving the problems of high-quality measuring testing of metal products from ferromagnetic materials by electromagnetic-acoustic transducers. The requirements are formulated for a pulsed source of a polarizing magnetic field, inductors, and core as part of electromagnetic-acoustic transducers. Taking into account the requirements, structural solutions have been proposed for constructing electromagnetic-acoustic transducers with a flat two-window inductor and a flat high-frequency inductor. Experimental studies aimed at improving ultrasonic electromagnetic-acoustic transducers with pulsed magnetic field sources have been performed. The possibility of providing the sensitivity of new transducers with thickness measurement, measuring control and diagnostics is shown. Technical solutions are proposed that reduce the effect on ultrasonic pulses of the received Barkhausen noise and coherent interference from the magnetostrictive conversion of electromagnetic energy into ultrasonic. The efficiency of using electromagnetic-acoustic transducers with a pulsed polarizing magnetic field is shown for measuring quality control of ferromagnetic products made by rolling, stamping and the like.Документ Powerful sources of pulse high-frequency electromechanical transducers for measurement, testing and diagnostics(НТУ "ХПИ", 2018) Plesnetsov, S. Yu.; Petrishchev, O. N.; Mygushchenko, R. P.; Suchkov, G. M.; Sotnik, S. V.; Kropachek, O. Yu.Development of powerful current radio pulses generators (CRPG) for powering high-frequency electromechanical transducers based on IGBT transistors. To carry out the research, the statements of the magnetic and electromagnetic fields interaction with electric and ferromagnetic material, electric circuits, structure of radio electronic devices theory were used. The main provisions for creating powerful broadband generators for powering electromechanical transducers based on IGBT transistors are determined. It is shown that the generators intended for use in measurements, testing and diagnostics should provide adjustment of the frequency and duration of the output current pulses, and also provide current in the transducer inductor of several hundred amperes. The connection between the power frequency of the resonant electromechanical transducer and the gap between the transducer and the surface of the metal being diagnosed is established. A CRPG variant for powering electromechanical transducers in the frequency range 1 ... 3 MHz and the duration of current pulses of 1 ... 20 periods of the filling frequency is developed and manufactured. The peak current in the inductor of a high-frequency electromechanical transducer has reached 450 A. For the first time, the possibility of using powerful IGBT transistorsin electronic devices working in a key mode in push-pull circuits for feeding high-frequency electromechanical transducers is shown. Using the resultsobtained will allow the creation of new instruments for measurement, control and diagnostics with wider characteristics.Документ Comparative analysis of electrical and thermal control of the lining state of induction apparatus of copper wire manufacture(НТУ "ХПИ", 2018) Zolotaryov, V. M.; Shcherba, M. A.; Belyanin, R. V.; Mygushchenko, R. P.; Kropachek, O. Yu.This article is intended to develop a technique for monitoring the lining state of induction channel furnaces for melting oxygen-free copper by monitoring changes in the distribution of thermal fields in their lining and carrying out a comparative analysis of the developed technique with the existing one that controls the electrical resistance of the melting channel of the furnaces. For carrying out the research, the theories of electromagnetic field, thermodynamics, mathematical physics, mathematical modeling based on the finite element method were used. A technique for diagnosing the lining state of the induction channel furnaces for melting oxygen-free copper has been developed, which makes it possible to determine the dislocation and the size of the liquid metal leaks by analyzing the temperature distribution over the body surface both the inductor and the furnace. The connection between the temperature field distribution on the surface of the furnace body and the dislocation and dimensions of the liquid metal leaks in its lining is determined for the first time. Using the proposed technique will allow to conduct more accurate diagnostics of the lining conditions of the induction channel furnaces, as well as to determine the location and size of the liquid metal leaks, creating the basis for predicting the working life of the furnace.