Вимірювальна техніка та метрологія
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Item Content(Видавництво Львівської політехніки, 2005-02-24)Item Electrical capacitance measurement by scattering ellipse approximation(Видавництво Львівської політехніки, 2005-02-24) Kostiukov, Ivan; National Technical University “Kharkiv Polytechnic Institute”This article is devoted to the substantiation of the possibility of electrical capacitance measurement utilizing equations that are based on the approximation of scattering ellipse, formed by signals proportional to the current flowing through the capacitive tested object and voltage drop on the tested object. On the contrary, to previously developed algorithms, which were based on the approximation of the scattering ellipse by applying the least-squares method, in this case, the approximation was carried out by simply using the values of signals amplitude directly determined from current and voltage curves. The value of the phase shift between the current and voltage curves, which is also necessary to approximate the shape of the scattering ellipse, was determined by using the cross-correlation method. Besides, the article provides formulas for calculating the reactive component of voltage drop on the tested object which is based on the approximation of scattering ellipse without using the least-squares method. Formulas for calculation of the reactive component of the voltage drop on the tested object after the reduction of the quadratic form of the elliptic curve to its canonical form are also given. The results of the impact of the reduction of the quadratic form of scattering ellipse to its canonical form on the value of correlation coefficient between sine curves of current and voltage as well as on the magnitude of major semi-axis and minor semi-axis of scattering ellipse are illustrated. Also, it was shown the relationship between the values of the reactive component of voltage drop on the capacitive tested object, which were determined before the reducing of the quadratic form of scattering ellipse to its canonical form and after such reducing. Despite the rejection of the applying of the least-squares method, to simplify the calculation algorithms, and also despite the presence of a significant noise component in sampled and processed curves of current and voltage, the experimental test has shown the sufficient level of accuracy and, consequently, the possibility of measuring the electric capacitance by approximating the scatter ellipse employing parameters of the quadratic form directly calculated from previously sampled sine curves of current and voltage.Item Means of measurement of relative quality indicators by immittance parameter(Видавництво Львівської політехніки, 2005-02-24) Pokhodylo, Yevgen; Yatsuk, Vasyl; Bubela, Tetiana; Lviv Polytechnic National UniversityThe paper describes the problems of implementation of the differential method of product quality assessment using the immittance method. The differential method of quality control is realized through a comparison of parameters of the immittance of the controlled and reference samples. The application of traditional meters of CLR-parameters complicates the process of the differential method implementation. Such units cannot directly measure relative quality. Virtually all models of such measuring instruments measure only the parameters of the monitored object through the input device. Thus, they are not adapted to the direct measurement of relative quality indicators. The authors propose to introduce a product pattern with the values of the code-controlled measure of admittance. These values are obtained by measuring the parameters of a standard pattern of products of a given quality level with a traditional immittance meter. The structure of the measuring instrument for the direct measurement of the relative quality index is given. The method is realized by comparing the parameters of the controlled object and the electrical standard pattern in the form of a code-controlled measure of admittance. This allows building quality control means for any nonelectrical products. Controlled products are supplied by electrical parameters of immittance with means of capacitive primary converters. Direct application of the differential method of quality assessment allows simplifying the measuring instrument as much as possible and reduce the time of product quality assessment. The proposed structure of the unit enables us to determine the deviation of the relative indicator from the value one. According to the obtained value of the indicator, products can be quickly classified by quality levels.Item On some joint laws of the field of gravity and electrometry(Видавництво Львівської політехніки, 2005-02-24) Tchaban, Vasil; Lviv Polytechnic National UniversityAdapted laws of statics of electric and gravitational fields in case of dynamic processes are used to obtain common laws of electricity and gravity. The mathematical description is made in a possible range of velocities in the usual three-dimensional Euclidean space and physical time, but bypassing the theory of relativity. This takes into account the finite speed of light propagation of electric and gravitational fields. For certainty, the derivation of the obtained results of gravity is duplicated by the methods of classical mechanics. Wave equations are obtained. The necessary attention is paid to the ratio of dimensions of parallel electrical and mechanical quantities.Item Thermometry: from sensitive material to thermoelectric thermotransducer(Видавництво Львівської політехніки, 2005-02-24) Stadnyk, Bohdan; Skoropad, Pylyp; Yatsyshyn, Svyatoslav; Lviv Polytechnic National UniversityThe hard operation conditions of temperature thermotransducers which involve their thermal cycling require special attention to the study of processes occurring in structural elements, in particular in thermometric materials. Operation impacts cause the drift of thermometric characteristics due to the influence of the few factors main of which seem to be the thermo structural stresses. Therefore, different kinds of sensitive elements were studied. Since traditional polycrystalline thermoelectrodes of thermocouples are inherent in the well-known drawback linked with recrystallization, there were investigated the liquid metals as the thermometric substances, melts, single-crystal materials, and metallic glasses. The need for metal glasses application in thermometry is substantiated, which allows eliminating thermally activated gradients of internal stresses in thermocouples ensuring high reproducibility and low drift of their thermo-EMF comparing to traditional materials. The analysis of sources of the instability of thermocouples’ drift is carried out. It demonstrates the density of heat and electric flows in stressed thermoelectrodes depends not only on temperature and electric potential gradient but also on the stresses’ gradient. This causes the dependence of thermometric parameters of both poly- and single-crystal substance of thermoelectrodes on the value and nature of stresses occurring within the operation cycle.Item Blood coagulation monitoring system(Видавництво Львівської політехніки, 2005-02-24) Maslov, Artem; Mashevska, Marta; Lviv Polytechnic National UniversityThis article describes the creation of a communication system between smartphones and various medical devices, also there is an analysis of different approaches to data transfer between devices, such as manual data entry, screen scanning using a seven-segment display recognition system, and Bluetooth low energy. The practical part demonstrates a developed communication system using Bluetooth technology. There is also implemented an automatic communication between devices that requires no user actions.Item Computer simulation of the influence of wind power plants on the compartments of the complex landscape system by the method of life cycle assessment(Видавництво Львівської політехніки, 2005-02-24) Pohrebennyk, Volodymyr; Ruda, Mariia; Bojko, Taras; Petrov, Oleksandr; Lviv Polytechnic National UniversityIt is proposed to apply the concept of life cycle assessment of alternative energy sources, such as wind turbines, to assess their environmental impact. Through simulation modeling, using SimaPro software, obtained was an integrated system of indicators of the impact wind energy systems on the layers subsystems of the compartments of complex landscape systems. A process tree has been built to identify potential impacts, as well as to characterize, weigh, and rank them. Based on the assessment analysis of various environmental impacts, it was determined that significant consequences for the layers of the subsystems of the complex landscape systems compartments usually arise at the stage of transportation, installation, and erection of wind turbines, as well as the removal of individual components or the entire turbine at the end of its operation. It is shown that the study of all the processes alone, starting from the formation and ending with the utilization of landscape-technogenic systems will reveal the possible integrated effects of their impact on the environment.Item Virtual measuring instruments as means of uncertainty evaluation(Видавництво Львівської політехніки, 2005-02-24) Havryliv, Denys; Velgan, Roman; Lviv Polytechnic National UniversityModern measuring instruments as highly technological, precise, multi-functional tools today are complex systems, and estimation of their uncertainty turns into a non-trivial task of science. To provide information about the probability of results, their convergence, and reproducibility, it is necessary to analyze the task-oriented measurement uncertainty. As an approach to determining the uncertainty of complex systems, to avoid the need for professionally experienced personnel and expensive “artifacts” used for evaluation, there is a method of a so-called virtual measuring instrument. In this method, the measurement process is simulated, taking into account the influence of the main disturbance parameters and conducting statistical analysis using the Monte Carlo approach. All characteristics of virtual modules repeat the properties of real devices but allow quick and qualitative evaluation of environmental parameters' effect on the accuracy, as well as the uncertainty of measurement. It allows us to evaluate the correctness of the result under the present conditions. The measurement uncertainty is usually caused by several major sources. Uncertainty depends on the method of measurement, but there are still common factors, i.e. uncertainty caused by measuring instruments, methods, operators, and environment. Among environmental influences, it is important to highlight – the change of light and temperature, which can vary widely variate at the production process, and at the same time have a crucial impact on the uncertainty of measurement. The paper presents a virtual measurement instrument method and its known implementations.Item Титульний аркуш до “Вимірювальна техніка та метрологія”(Видавництво Львівської політехніки, 2005-02-24)Item Вимірювання діелектричних втрат та діелектричної проникності методом зміщення системи координат за напругою(Видавництво Національного університету “Львівська політехніка”, 2006-01-31) Грибок, Микола; Національний університет “Львівська політехніка”Досліджена можливість вимірювання діелектричних втрат та діелектричної проникності електроізоляційних матеріалів нафтового або рослинного походження методом зміщення системи координат за напругою. Наведені схеми вимірювання та результати імітаційного моделювання похибок вимірювання.