https://rep.bntu.by/handle/data/108332 Sat, 04 Apr 2026 10:53:41 GMT 2026-04-04T10:53:41Z https://rep.bntu.by/handle/data/108340 Increasing of the Accuracy of Signalsʼ Time Parameters Measuring Using Double Pulse Trains Isaev, A. V.; Suchodolov, U. V.; Sushko, A. S.; Sheinikau, A. A. In modern diagnostics, much attention is paid to measuring of time parameters, as well as their change over time. The purpose of this work is to develop a method for measuring of time intervals which made it possible to increase the measurement accuracy by reducing errors associated with the instability of main parameters of the pulse signal. In the most of approaches used, the error associated with the instability of main parameters of signals under study is not enough taken into account. As an alternative, a spectral method is proposed in which the measurement of time intervals, as well as their changes, is performed based on the analysis of pulse sequences formed on the basis of characteristic points of the measured signal. For this a double pulse sequence was considered, an equation for the amplitudes of its spectral components was obtained, and in accordance with this it was determined that the delay time between double pulses is the most informative parameter. Using the Mathcad software, an analysis of the sensitivity regions was carried out for the change in the main parameters of the pulse sequence, namely the repetition rate, as the main destabilizing factor. As a result of the implementation of the developed technique, a structural diagram of the measuring system is proposed and an analysis of the measurement error associated with the instability of the main parameters of the pulse sequence is carried out. This error is estimated to be less than 0.01 %. The considered method makes it possible to increase the accuracy of measuring time intervals due to the almost complete elimination of the influence of the instability of the reference frequency and the amplitude of the generated pulses which is unattainable with modern hardware, including digital signal processing. Fri, 01 Jan 2021 00:00:00 GMT https://rep.bntu.by/handle/data/108340 2021-01-01T00:00:00Z https://rep.bntu.by/handle/data/108339 Application of Solutions of Uncorrected Tasksʼ Theory for Managing of Production Processesʼ Robustness Serenkov, P. S.; Romanchak, V. M.; Pesliak, I. E. The industrial revolution of “Industry 4.0” is currently underway at an active pace. Individualization of provided products and services, transition to single production, the issues of acceptability of production processes at the stage of development and design have became urgent. The aim of this work was to develop a strategy for a fundamental solution to the task of guaranteed acceptability of production processes as an integral quality characteristic. We have proposed a systematic approach to strategy development. The basis of the approach was the theory of incorrect tasks solving. We adapted signs of correctness of mathematical tasks by J. Adamar to the tasks of ensuring acceptability of production processes (technological and measurement). They were used in the part of identification of properties of display of incorrectness and ways of incorrectnessʼ management. We have proposed to consider the property of robustness as a generalized index of acceptability for production processes (technological and measurement). We substantiate the equivalence of the concepts of incorrectness of tasks according to J. Adamar and losses of robustness of production processes. We conclude that the developed approaches and techniques of the theory of incorrect tasks can be put in a basis of the system approach to an estimation and management of losses of robustness of production processes. We have proposed a classification of situations of robustness losses in production processes in accordance with the classification of the signs of incorrect tasks by J. Adamar. We have developed a two-step algorithm for ensuring the robustness of production processes at the stage of their development. It included identification of the sources of robustness losses and management of input factors that cause significant variation in process output. This has given a practical implementation of a strategy to guarantee the acceptability of production processes. We have systematized the sources of potential losses in the robustness of production processes and proposed a two-stage mechanism for managing them. We have justified rational methods of ensuring the robustness of production processes for each stage based on, the practice of uncorrected tasks solving. We have proposed a method for ensuring high efficiency of robustness loss management in certain situations. The principles of G. Taguchiʼs robust redesigning of production processes formed the basis of our method. Fri, 01 Jan 2021 00:00:00 GMT https://rep.bntu.by/handle/data/108339 2021-01-01T00:00:00Z https://rep.bntu.by/handle/data/108338 Influence of Geometry and Boundary Conditions in Area of the Cohesion between Materials on the Reflection of an Ultrasonic Beam. Part 2. Features of Experimental Simulation Baev, A. R.; Levkovitch, N. V.; Asadchaya, M. V.; Mayorov, A. L.; Razmyslovich, G. I.; Burnos, A. Y. Improving the efficiency of diagnostics of objects with layered structure as applied to detection of poorly detectable material bonding defects is an important production task. The aim of the work was to experimentally simulate ultrasonic scattering by samples of proposed defect simulator designs with discretely and smoothly varying boundary conditions correlating with the phase response of longitudinal waves during their interaction with the defect boundary of contacting materials. A brief analysis of some methods and means for experimental simulation of the volume and surface wave scattering at the interfaces of contacting materials as applied to improvement of method of detection of poorly detectable adhesion defects of materials proposed earlier was carried out. For this purpose an immersion installation working in the shadow mode and allowing for simulation the spatial fields of scattered longitudinal waves at inhomogeneous or defective adhesion boundaries was developed and constructed. It is assumed that the waves interacting with such a boundary acquire a discrete or smoothly varying phase shift which significantly affects the formation of the scattering field in its peripheral zone. The greater this shift, the stronger these changes are, which can significantly increase the sensitivity of detection of poorly detected defects. In order to increase the efficiency of such inspection and to develop its methodology a new principle of simulation of such defects has been proposed. Experimental study of longitudinal waves scattering using the developed installation and defect simulators, simulating discretely and smoothly changing boundary conditions which are consistent with a change in the phase shift of the scattered waves is carried out. The amplitude dependences of the scattering field vs. the receiving angle received mainly in the range from - 20º to + 20º and the displacement of the simulated defect relative to the axis of the probing acoustic beam were obtained. As it has been established, there is a quality conformity between the calculated and experimental data. The present study is of interest for solving a number of tasks of increasing efficiency of ultrasonic testing of modern objects with layered structure and will contribute to practical application. Fri, 01 Jan 2021 00:00:00 GMT https://rep.bntu.by/handle/data/108338 2021-01-01T00:00:00Z https://rep.bntu.by/handle/data/108337 Application of the Correlation Measurement Method for Reconstructing of the Velocity Profile with Spatial and Temporal Discretization in Studies of the Hydrodynamics of Turbulent Flows Based on the Matrix Conductometry Method Dmitriev, S. M.; Khrobostov, A. E.; Solncev, D. N.; Barinov, A. A.; Chesnokov, A. A.; Konovalov, I. A.; Makarov, M. A.; Zyryanova, T. K. The correlation method for measuring of the coolant flow rate is used in the operation of nuclear power plants and is widespread in research practice including study of turbulent flows hydrodynamics. However the question of its applicability and possibilities in studies using the matrix conductometry method remains open. Earlier the algorithm for determining of the correlation flow rate using a conductometric measuring system was highlighted and the error of the results obtained was estimated and the dependence of the influence of noise and the time of data collection on the reliability of results was investigated. These works were carried out using two independent mesh sensors and the issue of the resolution of local velocity components was not covered. The purpose of this work was to test the correlation method for measuring velocity with temporal and spatial sampling using two-layer mesh conductometric sensors. As the result velocity cartograms were obtained over the cross-section of the experimental model with quasi-stationary mixing and the value of the average flow rate is in good agreement with the values obtained from the standard flow meters of the stand. Also measurements were carried out at a non-stationary setting of the experiment and realizations of the flow rate and velocity components of the flow at the measuring points were obtained. Analysis of the obtained values allows to conclude about the optimal data collection time for correlation measurements, as well as the reliability of results. Fri, 01 Jan 2021 00:00:00 GMT https://rep.bntu.by/handle/data/108337 2021-01-01T00:00:00Z