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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 Improving metrological characteristics of measuring instruments by discrete wavelet noise filtering using the recursion method(Національний науковий центр "Інститут метрології", 2022) Onufrienko, D.; Taranenko, Yu.; Suchkov, G. M.The method of recursive discrete wavelet noise filtering for improving metrological characteristics of measuring instruments was investigated for the first time. Methods with a common threshold for all decomposition levels, methods without threshold with a simple zeroing of detail coefficients until the minimum mean square (RMS) error is reached, and methods with universal threshold for detail coefficients at each decomposition level were studied. Twenty different types of measurement signals from the popular PyWavelets library were analyzed. The functions of filtering methods with a common threshold were determined, for which the use of recursion reduces the filtering error from 10 to 50%. For methods without threshold and with universal threshold, the recursion does not reduces the error by multiple filtering of measurement signals. To apply the recursion to the method with a common threshold for all decomposition levels, a mathematical model based on the fundamental equations of wavelet filtering was constructed. The character of distribution of the filtering RMS error depending on the number of reversible cycles is investigated. It was summarized that for the measurement signal models under consideration, the maximum error reduction occurs between the zero cycle, in which the initial measurement signal is filtered, and the first level of recursion. Further reduction of the filtering error with increasing number of recursion cycles occurs according to the law close to hyperbolic.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 Measuring the amplitude-time characteristics of a pulsed high-intensity gamma radiation acceleratorVarian Clinac 600C aCdTe detector(STC "Institute for Single Crystals", 2019) Grigoryev, A. N.; Bilyk, Z. V.; Litvinov, Yu. V.; Cherniavskiy, I. Yu.; Polyansky, N. E.; Snarenky, V. P.; Samofalov, I. A.; Voronkin, E. F.; Sosnutska, O. O.; Petrukhin, S. Yu.; Suchkov, G. M.; Bilyk, N. G.; Indykov, S. N.; Matykin, V. B.; Pysariev, S. A.; Matykin, O. V.; Menshov, S. N.Measurements of the amplitude-time characteristics of a high-intensity pulsed gamma radiation accelerator Varian Clinac 600C with photon energy from 1 to 6 MeV on the equipment using a CdTe detector in both current and pulse modes have been carried out. It is shown that the operation of the CdTe detector in the current mode allows one to control the frequency of the accelerator pulses, and the operation of the CdTe detector in the pulse mode allows for determining the dose in each pulse with an error of 0.06 %. Monitoring the operation of the accelerator Varian Clinac 600 C shows that the pulses come in batches; within the batch, the pulse repetition period corresponds to a specified frequency at the accelerator, while the repetition period of the batches differs from the specified frequency. Dose control in the pulses showed its 5 % excess over the average value during the first 2.5 s of the accelerator operation, whereas during the last 2 s, the dose reduction by 1.8 % was observed.Документ Electromagnetic-acoustic method of ultrasonic pulse excitation and reception in metal products(Харківський національний університет імені В. Н. Каразіна, 2017) Plesnetsov, S. Yu.; Suchkov, G. M.The problem of the main factors infl uence on the electro-magnetic energy to ultrasound conversion in test-ing of electrically conductive or ferromagnetic materials is considered. The necessity to provide the polarizing magnetic fi eld induction maximum value and the maximum current in the electromagnetic-acoustic transducer high-frequency coil is shown. A converter for co-radiation and reception of pulses of ultrasonic vibrations has been developed and tested, providing useful information signal amplitude of up to 50 dB.Документ Mathematical Modeling of Physical Processes of Electromagnetic Field Transformation in Elastic Oscillations Field in Microthick Layers of Metals(Сумський державний університет, 2017) Plesnetsov, S. Yu.; Migushchenko, R. P.; Petryschev, O. N.; Suchkov, G. M.; Khrypunov, G. S.The results of the mathematical studies on the modeling of high-frequency electromagnetic field conversion in the field of elastic oscillations process in microthick surface layers or electrically conductive ferromagnetic material thin films placed in a magnetic field are given, taking into account the coherence of elastic, electric and magnetic properties of the metal. It is shown that in practical calculations, especially in the case of high-frequency oscillations, it is necessary to take into account thickness of skin layer in which electromagnetic field transforms into acoustic field.Документ Simulation of Electromagnetic Conversion Process Under Torsion Waves Excitation(Інститут електродинаміки НАН України, 2018) Plesnetsov, S. Yu.; Petrishchev, O. N.; Mygushchenko, R. P.; Suchkov, G. M.Mathematical simulation and calculation of electromagnetic fields in the electromagnetic-acoustic transducer of rational design are performed under non-dispersive torsional waves excitation in tubular electrically conductive ferromagnetic hollow rods of small diameter, taking into account spatial, frequency, energy and material factors. The results of the research can be used to simulate and construct exciting EMATs for measuring, monitoring, and diagnostic equipment in the energy, nuclear, chemical and other industries in view of ultrasonic studies of ferromagnetic tubular products.Документ Simulation of Electromagnetic Conversion Process Under Torsion Waves Excitation(Інститут електродинаміки НАН України, 2018) Plesnetsov, S. Yu.; Petrishchev, O. N.; Mygushchenko, R. P.; Suchkov, G. M.Mathematical modeling of the electromagnetic-acoustic transducer (EMAT) for excitation of nondispersive torsional waves in tubular electrically conductive ferromagnetic hollow rods of small diameter is performed taking into account all the factors that determine the design of the EMAT. The solutions of the differential equation for the values of the electromagnetic fields formed by the high-frequency coil of the device in the gap between the transducer and the tubular ferromagnetic product are found. The results of the research can be used to simulate and design exciting EMATs for measuring, monitoring, and diagnostics in the energy, nuclear, chemical and other industries for ultrasonic test of ferromagnetic tubular products.Документ Physical principles of non-contact ultrasonic frequency sensors creation for the study of nanocrystalline ferromagnetic materials(Сумський державний університет, 2018) Plesnetsov, S. Yu.; Mygushchenko, R. P.; Petryschev, O. N.; Suchkov, G. M.; Khrypunova, A. L.A mathematical model is developed to determine the force impacts that are formed when the electro-magnetic field is transformed into a field of ultrasonic oscillations in the skin layer of an electrically conductive ferromagnetic material of an anisotropic magnetic permeability. The main factors determining the excited acoustic field with allowance for permissible limitations are established. It is shown that the main contribution to the acoustic vibrations energetics is made by the magnetostrictive component of the skin layer material, in which the high-frequency electromagnetic field is transformed into an acoustic field.