Вимірювальна техніка та метрологія. – 2023. – Випуск 84, №1

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Measuring Equipment and Metrology : scientific journal. – Lviv : Lviv Politechnic Publishing House, 2023. – Volume 84, № 1. – 68 р.

Вимірювальна техніка та метрологія

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    Aspects of standardization and countering food terrorism in the conditions of martial law
    (Видавництво Львівської політехніки, 2023-02-28) Chorna, Olha; Baitsar, Roman; Lviv Polytechnic National University
    One of the important issues in the field of ensuring product safety at food industry enterprises is the prevention of bioterrorism. The emergence of bioterrorism is associated with the rapid development of genetic engineering and the emergence of the latest biotechnologies in the world, which contributes to a quick and easily accessible way of neutralizing the enemy. In connection with the full-scale invasion of the Russian Federation on the territory of Ukraine, the occupation and the holding of illegal referendums, and the use of all types and types of terrorism, market operators whose location is tangential to the occupied territories should strongly pay attention to food terrorism and carry out a biorisk assessment depending from the field of production.
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    Qualitative assessment of ecosystem services for recreation and tourism in the spatio-temporal geosystem
    (Видавництво Львівської політехніки, 2023-02-28) Boyko, Taras; Ruda, Maria; Paslavskyi, Mykhailo; Lviv Polytechnic National University; National Forestry University of Ukraine
    The paper proposes a comprehensive method of qualitative evaluation of services provided by various providers, which are expressed by characteristics that avoid a quantitative representation. The research foresees the application of the well-known method of deployment of quality functions, the development of which consists of the possibility of determining the coefficients of the weighting of technical characteristics of cultural ecosystem services for recreation and tourism of the spatiotemporal geosystem. To take into account the priority of consumer requirements, the expert method of pairwise comparisons was introduced, which was modified so that possible conclusions could be considered, in particular, the evaluation of the equivalence of characteristics was applied. To obtain the degree of correlation between the characteristics determined by experts based on consumer requirements and the technical characteristics of cultural ecosystem services for recreation and tourism, it is proposed to utilize the fuzzy logic method. Since both the presence of correlations links and the degree of correlation between consumer requirements and technical characteristics are the result of the interaction of a set of various factors, among which a significant number may be random, based on the central limit theorem, as well as the experience of applying correlation coefficients in other areas, a conclusion is drawn, that the probability distribution function of correlation degrees is properly described by a Gaussian curve. The value of the technical characteristics of the specified ecosystem services for three spatiotemporal geosystems was also obtained with the help of the fuzzy logic method.
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    European and international principles for quality management in education using intelligent technologies
    (Видавництво Львівської політехніки, 2023-02-28) Ivanyshyn, Alla; Lviv Polytechnic National University
    The article compares the international and European requirements for institutions of higher education. General international principles of quality management were also considered and adapted to institutions of higher education. The main requirements for the quality management system (QMS) of a higher education institution (HEI) following international and European standards) as well as the advantages and main requirements for the implementation of the quality management of educational services, as a tool for managing the processes of providing educational services and improving their quality.
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    Comparative analysis of expert evaluation of quality criteria of the educational program for the field of computer-integrated technologies
    (Видавництво Львівської політехніки, 2023-02-28) Gordiyenko, Tetyana; Velychko, Oleh; Salceanu, Alexandru; State University of Telecommunications; State Enterprise “Ukrmetrteststandard”; Gheorghe Asachi Technical University of Iaşi
    The article presents the results of comparative expert research to establish the importance of the applied national criteria for the quality of the educational program (CQEP) of higher education institutions (HEIs). For these studies, a group expert assessment of the importance of the CQEP for the educational program (EP) in the field of computer-integrated technologies was applied. The teaching staff of two universities is involved in conducting such an evaluation: The State University of Telecommunications (Ukraine) and the Gheorghe Asachi Technical University of Iaşi (Romania). To conduct this research, the existing CQEP and their sub-criteria and a special algorithm of group expert evaluation were used. It has been established that the most important CQEP and their sub-criteria include, first of all, CQEP regarding human resources, the educational environment, material resources, and the structure and content of the EP. The greatest spread of experts’ opinions (from the weightiest to the least weighty) can be stated for the sub-criteria of CQEP regarding access to EP and recognition of training results and transparency and publicity. With this in mind, this CQEP sub-criteria requires close attention when revising them for a better balance of the CQEP subcriteria system. Harmonization of the list of fields of knowledge and specialties for which higher education students are trained with the International Standard Classification of Education, as well as the national terminological and conceptual apparatus with the international one, should be considered extremely appropriate in Ukraine. The issue of prioritizing the preparation of higher educational institutions for the accreditation of the EP, meeting the most essential requirements of the sub-criteria of the CQEP, and taking into account their significant number, remains relevant. This also determines the relevance and necessity of conducting special expert studies on the comparison of the importance of CQEP for different fields of knowledge.
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    Computer visual inspection of pear quality
    (Видавництво Львівської політехніки, 2023-02-28) Ilchuk, Mykhailo; Stadnyk, Andrii; Lviv Polytechnic National University
    A brief description of the basic stages of image processing is given to pay attention to the segmentation stage as a possible way to improve efficiency in decision-making. The main characteristics of the presented model are visual signs, such as color, shape, the presence of a stem, and others. Due to the different approaches in image processing, a high level of truthfulness is achieved, which is expressed in the percentage ratio of the accuracy of decision-making and varies in the range from 90 to 96%. Therefore, the results obtained in this work make it possible to automate the process of visual inspection with the prospect of increasing the speed and quality of product sales for the consumer.
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    Automation of measurements on the state standard of the unit of phase shift angle between two voltages
    (Видавництво Львівської політехніки, 2023-02-28) Velychko, Oleh; Kulish, Yuliia; State Enterprise “Ukrmetrteststandard”
    The phase is one of the main parameters of the oscillatory process in electric circuits and contains two components – constant and variable. More often, it is not the actual phase that is measured, but the phase shift angle (PSA) between two oscillating processes (voltages or currents) of the same frequency in the range from 0 to 360˚. Then the PSA is equal to the difference between the constant components of the phases of the two oscillations and does not depend on the start of the time count. Most of the modern methods of measuring the phase and PSA are based on the methods of discretization and digital signal processing – complex Fourier transform, least squares, etc. There are many varieties and improvements of these methods, which have different characteristics of measurement accuracy. The LabVIEW graphical programming environment has already become a general- purpose programming environment. Advantages of LabVIEW include simple networking, implementation of common communication protocols, powerful toolkits for process control and data fitting, fast and simple user interface design, and an efficient code execution environment. The article presents the results of the automation of measurements on the State Standard of the PSA between two voltages in the frequency range from 5 Hz to 10 MHz. Automation of precision measurements of PSA using the LabVIEW software environment provides advantages in comparison with manual measurements, in particular, reducing the time of measurement and processing of its results by at least three times. This ensures an increase in the productivity of metrological works; increasing their efficiency and quality, and the possibility of increasing the number of measurements (up to 1000), which allows for improve the root mean square deviation of not less than one and a half times, and reduce the overall standard measurement uncertainty, respectively.
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    Sensitive elements of temperature converters based on HfNi1-xCuxSn thermometrical material
    (Видавництво Львівської політехніки, 2023-02-28) Krayovskyy, Volodymyr; Rokomanyuk, Mariya; Luzhetska, Nataliya; Pashkevych, Volodymyr; Romaka, Volodymyr; Stadnyk, Yuriy; Romaka, Lyubov; Horyn, Andriy; Lviv Polytechnic National University; Ivan Franko National University of Lviv
    The results of experimental studies of sensitive elements of temperature transducers based on semiconductor thermometric material HfNi1-xCuxSn are presented. Thermometric materials HfNi1-xCuxSn, x=0.01–0.10, were produced by fusing a charge of components in an electric arc furnace with a tungsten electrode (cathode) in an atmosphere of purified argon under a pressure of 0.1 kPa on a copper water-cooled base (anode). Heat treatment of the alloys consisted of homogenizing annealing at a temperature of 1073 K. The samples were annealed for 720 hours. in quartz glass ampoules vacuumed to 1.0 Pa in muffle electric furnaces with temperature control with an accuracy of ±10 K. Diffraction data arrays were obtained on a STOE STADI-P powder diffractometer (Cu Kα1 radiation), and the structural characteristics of HfNi1-xCuxSn were calculated using the Fullprof program. The chemical and phase compositions of the samples were monitored using metallographic analysis (scanning electron microscope Tescan Vega 3 LMU). The thermoelectric pair platinum-thermometric material Pt-HfNi0.99Cu0.01Sn was the basis of the thermoelectric converter. Modeling of thermometric characteristics of sensitive elements of thermotransducers in the temperature range of 4.2– 1000 K was carried out by the full potential linearized plane wave method (Full Potential Linearized Augmented Plane Waves, Elk software package). The results of experimental measurements served as reference currents for modeling characteristics. X-ray phase analysis showed the absence of traces of extraneous phases in the diffractograms of the studied samples of HfNi1-xCuxSn thermometric materials, and the microprobe analysis of the concentration of atoms on their surface established the correspondence to the original composition of the charge. Refinement of the crystal structure of HfNi1-xCuxSn showed that the introduction of Cu atoms orders the structure, which makes it stable, and the kinetic characteristics are reproducible during thermocycling at temperatures T=4.2–1000 K. Ordering the structure of the thermometric material HfNi1-xCuxSn leads to changes in the electronic structure. At the same time, the number of donors decreases – Ni leaves the Hf position, and the substitution of Ni atoms for Cu leads to the generation of structural defects of the donor nature (Cu atoms contain more 3d-electrons), and another donor band εD Cu will appear in the band gap εg. For the sensitive elements of thermoconverters at Cu impurity concentrations x=0.005 and x=0.01, the temperature dependences of the specific electrical resistance ln(ρ(1/T)) contain activation areas, which is consistent with the results of electronic structure modeling. This indicates the location of the Fermi level εF in the band gap εg, and the negative value of the thermopower coefficient α(T) at these temperatures specifies its position – near the conduction band εC. The value of the activation energy from the Fermi level εF to the bottom of the conduction band εC was calculated. For the base semiconductor n-HfNiSn, the Fermi level εF lies at a distance of εF=81 meV from the co εC conduction band εC, and in the sensitive elements of thermoconverters with concentrations of HfNi0.995Cu0.005Sn and HfNi0.99Cu0.01Sn – at distances of εF=1 meV and εF=0.3 meV respectively. Therefore, an increase in the concentration of the Cu donor impurity leads to a rapid movement of the Fermi level εF to the bottom of the conduction band at a rate of ΔεF/Δx≈81 meV/%Cu. The impurity concentration x=0.01 is sufficient for the metallization of the conductivity of sensitive elements of HfNi1-xCuxSn converters at low temperatures. This is possible if the Fermi energy εF is close to the conduction band εC (εF=0.3 meV), which simplifies the thermal ionization of donors and the appearance of a significant number of free electrons. However, this impurity donor zone still does not intersect with the bottom of the conduction band εC. At concentrations of the Cu donor impurity in HfNi1-xCuxSn, x=0.2–0.07, the high-temperature activation regions disappear on the temperature dependences of the resistivity ln(ρ(1/T, x)), which indicates the movement of the Fermi level εF from the band gap εg to the conductivity εC. At the same time, the values of specific electrical resistance ρ(T, x) increase monotonically with increasing temperature), and the scattering of electrons by phonons determines the conductivity of sensitive elements of thermotransducers based on the thermometric material HfNi1-xCuxSn. The metallization of the electrical conductivity of the thermometric material HfNi1-xCuxSn at concentrations x>0.01 is accompanied by a rapid decrease in the values of the thermopower coefficient α(x, T). Thus, if in n-HfNiSn at a temperature of T=80 K, the value of the thermal erst coefficient was αx=0=–178 μV/K, then in the HfNi0.93Cu0.07Sn material αx=0.07=–24 μV/K. The results of the kinetic properties of HfNi1-xCuxSn are consistent with the conclusions of structural and energetic studies. The simulation of the conversion functions of the sensitive elements of the resistance thermometer and the thermoelectric converter in the temperature range of 4.2–1000 K was carried out. As an example, the conversion functions of the thermoelectric pair Pt-HfNi0.99Cu0.01Sn are given. The ratio of change of thermo-EMF values to the range of temperature measurements in thermocouples is greater than all known industrial thermocouples. However, due to the metallization of the conductivity of the thermometric material HfNi1-xCuxSn, x>0.01, the temperature coefficient of resistance (TCR) of the obtained resistance thermometers is greater than the TCR of metals, but is inferior to the value of TCR of sensitive elements made of semiconductor materials.
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    Зміст до “Вимірювальна техніка та метрологія”
    (Видавництво Львівської політехніки, 2023-02-28)
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    Visualization method for multidimensional random processes
    (Видавництво Львівської політехніки, 2023-02-28) Poliarus, Oleksandr; Lebedynskyi, Andriy; Chepusenko, Yevhenii; Lyubymova, Nina; National Automobile and Highway University; State Biotechnological University
    The article proposes a method for visualizing multidimensional random process realizations using the example of the concentrations of harmful gases emitted into the atmosphere from a thermal power plant. The method is based on the transformation of gas concentration values in one point of multidimensional space at the same time into a two-dimensional curve, which is described by the sum of products of normalized concentrations by orthogonal Legendre functions of the corresponding order. The combination of such curves on a two-dimensional plane at discrete times creates a characteristic image that can be used to visually detect features of gas concentrations over time by a human operator.
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    Титульний аркуш до “Вимірювальна техніка та метрологія”
    (Видавництво Львівської політехніки, 2023-02-28)