Т. 11, № 2
https://rep.bntu.by/handle/data/75126
2024-03-28T09:08:31ZРеализация спектрального метода определения динамических характеристик средств измерений
https://rep.bntu.by/handle/data/75231
Реализация спектрального метода определения динамических характеристик средств измерений
Сабитов, А. Ф.; Сафина, И. А.
Основным требованием спектрального метода определения динамических характеристик средств измерений (СИ) является установление амплитудного спектра сигнала в его информативной части, включающей значение амплитудного спектра на нулевой частоте. Существующие низкочастотные анализаторы спектра имеют рабочий диапазон частот, лежащий выше нулевой частоты, что приводит к погрешности определения динамических характеристик СИ спектральным методом. Целью данной работы являлась разработка программы вычисления амплитудного спектра сигналов, начиная от нулевой частоты, для реализации спектрального метода определения динамических характеристик СИ на компьютерах, оснащённых математическим пакетом MatLab. Для реализации спектрального метода определения динамических характеристик средств измерений разработана программа в среде MatLab 2013b, позволяющая определять амплитудный спектр сигнала от нуля герц. В программе заложено считывание исходных данных из таблиц в формате Excel и представление вычисленного амплитудного спектра в виде диаграммы и таблицы отчётов. Показано, что разработанная программа вычисляет амплитудный спектр сигналов со средним квадратическим отклонением не более 3,4 % на интервале частот от 0 до 10 рад/с. Вычисленный амплитудный спектр позволяет определять постоянную времени апериодических средств измерений первого порядка с погрешностью не более 0,166 % при любом уровне помех, если их частоты находятся за пределами информационной части спектра. На примере высокочастотной помехи в переходной характеристике некоторых средств измерений продемонстрировано заявляемое преимущество спектрального метода определения динамических характеристик с использованием разработанной программы.
2020-01-01T00:00:00ZAbout Possibility of Remote Diagnostics of the Respiratory System by Auscultation
https://rep.bntu.by/handle/data/75229
About Possibility of Remote Diagnostics of the Respiratory System by Auscultation
Zaitseva, E. G.; Chernetsky, M. V.; Shevel, N. A.
Development of technical base, software, accumulated information on the diagnosis of the respiratory system provided the prerequisites for creating remote diagnostics of the human respiratory system through auscultation. The known methods do not solve the problem of determining auscultation points at patent´s housing without a diagnostic specialist. The purpose of this study is to develop a method for remote diagnostics of the respiratory system which provides ability to determine the points of auscultation without presence of a diagnostic specialist. The definition of auscultation points is provided using a computer program that allows to calculate the points´ coordinates based on the coordinates of points that determine the anatomical structure of the patient's torso. The patient or his assistant places the recording device at the auscultation points combining their images on the display with the image of the location of the recording device. The signal recorded at the auscultation point is remotely transmitted to a specialist for direct analysis and/or computer processing. The diagnostic module consists of two main units. The first unit contains a stethoscope, microphone, and amplifier connected to a mobile phone or other similar device containing an accelerometer. The patient or his assistant at the housing uses the unit. The second unit is a mobile phone with a mechanical marker or a computer with the ability to access the network in conjunction with the necessary software and is used remotely by a diagnostic specialist. The layout of the unit for recording and transmitting breath sounds was made. To avoid discrepancies in the diagnostic results the technical characteristics of the module elements must be normalized. Unified software is required for the module to function. The organizational tasks that need to be solved for the implementation of diagnostics are formulated. Use of the method of remote diagnostics of the respiratory system, providing the ability to determine points of auscultation without the direct presence of a diagnostic specialist and the module will allow increasing efficiency of treatment of pulmonary diseases reduce infection risks and economic costs.
2020-01-01T00:00:00ZTests of Impregnation Speed of Electrotechnical Pressboard with Insulating Oil
https://rep.bntu.by/handle/data/75228
Tests of Impregnation Speed of Electrotechnical Pressboard with Insulating Oil
Kozak, C.
The paper presents a new test stand for ivestigating the rate of penetration of transformer oil through electrotechnical pressboard. The stand consists of a pipe, to the lower end of which is glued a pressboard plate. The pipe is filled with insulating oil. A mirror is placed under the plate, which directs its image to the lens of the camera, which takes a series of photographs at a given time interval. After being saturated with the insulating oil, the pressboard changes colour from light to dark yellow. The absorbing time is defined as the time in which a dark yellow spot appears on the lower light surface of the pressboard after the pipe is filled with oil. A new way of determining capillary diameters has been developed when the number of capillaries is unknown and the volume of liquid flowing through them is not measurable. The distribution of the times of penetration of transformer oil through 2 mm thick electrotechnical pressboard was determined, the values of which range from about 220 min to about 550 min. It was found that the radii of capillaries through which the insulating oil penetrates are within the range from about 45 nm to about 70 nm. Due to the structure of the pressboard, which consists of cellulose fibres, arranged more or less tightly, there are capillaries in the structure of the board, each of which has sections of varying lengths of radii. This means that short sections of a single capillary can have radii both smaller than 45 nm and larger than 70 nm. The developed stand and the new analysis method can be used for testing various porous materials for penetration by various liquids.
2020-01-01T00:00:00ZIonization Efficiency in a Hot Flat Disc-Shaped Cavity
https://rep.bntu.by/handle/data/75226
Ionization Efficiency in a Hot Flat Disc-Shaped Cavity
Turek, M.
Hot cavity ion sources of different kinds are widely used in nuclear and mass spectroscopy, especially in on-line isotope separation devices attracting attention of scientists and engineers looking for high ionization efficiency, robustness and beam purity. In the paper a new type of hot ionizer cavity is proposed: namely cavity having the shape of a flat disc, which may be especially suitable for short-lived nuclides to be ionized. A numerical model of the ion source is presented in the paper. The particle tracking code takes into account ionization at hot surfaces and enables modeling of both flat disc cavity and standard elongated cavity ionizers. The code enables calculation of total ionization efficiency and is suitable for stable and long-lived nuclides. Influence of the flat disc cavity geometry (thickness and radius) and its temperature on total ionization efficiency was considered – it was shown that the efficiency increases with cavity radius due to the growing number of particle-wall collisions. This effect may be important in the case of the hard-to-ionize nuclides. The optimal ionizer geometry is characterized by 90 % efficiency, even for substances with rather low ionization coefficient (of order 0.05). The role played by the size of the extraction opening is explained – it is demonstrated that the ionization efficiency increases due to the opening radius reduction. It is also proven that extraction voltage of 1–2 kV is sufficient to maintain optimal ionizer efficiency.
2020-01-01T00:00:00Z