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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 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.