The issues of measuring the wave resistance and complex reflection and transmission coefficients of devices operating at ultrahigh frequencies in coaxial waveguides are considered. Measurements of these parameters are important in the development and production of communication and information transmission systems, radar and radio navigation systems. In order to ensure the uniformity of measurements, reproduction and transmission of wave resistance units and complex reflection and transmission coefficients to measuring instruments with coaxial connectors of type 1 mm in the frequency range 0.01–67 GHz, the state primary standard of the unit resistance in coaxial waveguides GET 75-2023 has been approved. It includes means of reproducing the unit of wave resistance, complex reflection coefficients, a comparator and comparison standards in a coaxial path with a cross section of 1.0/0.434 mm with a connector of type 1 mm. The expressions for calculating the parameters of coaxial waveguides with bimetallic conductors are refined. The technical characteristics and results of metrological studies of GET 75-2023 are presented. The results of the research confirmed the high accuracy of GET 75-2023, which has comparable metrological characteristics with the standards of national metrological institutes of other countries.

Prior to the requirement for testing and calibration laboratories to take into account the risk of statistical assumptions, false positive and false negative decisions in international documents, it was found that the methodology of the “Guide to Expressing Measurement Uncertainty” based on the Bayes approach and the Monte Carlo method for calculating probabilistic risk characteristics is not applicable. A later draft revision of the “Manual on the Expression of Measurement Uncertainty” attempted to shift the interpretation of measurement uncertainty from the scattering parameter to the probability distribution. An attempt to contribute to solving the problem of definitional uncertainty in the International Dictionary of Basic and Basic Terms of Metrology was also unsuccessful. In the new version of the dictionary of general statistical terms and probability theory terms, the term measurement uncertainty is excluded, and one of the notes states that “the probability distribution fully describes the probabilistic properties of the uncertainty of the result”. However, due to the new requirements for risk calculations, international documents were urgently put into effect without radical assessments of the inapplicability of the Bayes approach and the Monte Carlo method, the disadvantages were renamed limitations, but there are no specific instructions for calculating risks. Based on the experience of the compositional approach to estimating accuracy, a procedure based on the convolution of probability distributions in the form of a modified reversal formula is recommended, which allows taking into account the definitive uncertainty in the moment approach. It is established that the method of accounting for the definitive uncertainty by convolution of uniform distributions is practically suggested in the text of the “Manual on the expression of measurement uncertainty”, but not used.

The efficiency of estimating the numerical characteristics of a family of the lognormal distribution law of a onedimensional random variable under conditions of large volumes of statistical data is considered. To circumvent the problem of large samples, methods of discretization the range of values of a random variable based on the formulas of Sturges, Brooks-Carruthers, Heinhold-Gaede and the formula proposed by the authors of this article are used. Data arrays have been generated that make it possible to evaluate the numerical characteristics of the laws of distribution of random variables, taking into account their discrete values. Based on the transformed data arrays, estimates of the mathematical expectation, standard deviation, skewness and kurtosis coefficients were calculated. Estimates of the numerical characteristics of the considered distribution laws under the conditions of a continuous and discrete random variable are compared for different volumes of initial statistical data. The effectiveness of methods for estimating the numerical characteristics of the family of the lognormal distribution law based on the initial statistical data and on the results of transformations of these data using known discretization formulas has been established. The reliability of the comparison of the effectiveness indicators of the studied methods was confirmed by using the Kolmogorov-Smirnov criterion. It is shown that the discretization formula proposed by the authors of this article is better and more effective compared to traditional methods.

The most pressing problems in terms of production are increasing labor productivity and the quality of its results. One of the main ways to increase labor productivity is the development of new progressive technological processes. There are methods for controlling batches of products that can reduce the time of its control and increase labor productivity, which include methods of statistical quality control based on an alternative criterion. However, a sample from a batch of products must be fully controlled. When inspecting with one inspection tool, the sample inspection time is no less than the sum of the inspection times of all sample items. The purpose of this work is to develop a method for determining the number of defective products in a sample with one inspection tool, allowing to reduce the sample inspection time to the minimum possible. A method is proposed for determining the number of defective products of a certain class in a sample with one inspection tool using samples, which allows to signifi cantly reduce the sample inspection time. The samples are connected in parallel to the controlled products and are connected in series. All products in the sample with samples are controlled simultaneously, the total value of the controlled parameter is determined for them, and the number of defective products in the sample is determined by the formula. The effectiveness of the method is shown using the example of monitoring electromagnetic relays. The method makes it possible to reduce the sample inspection time to the minimum possible value, equal to the inspection time of one product.

The development of optical-electronic instruments for measuring linear and angular quantities based on focal-plane array (photomatrices) using a digital phase analyzer (digital raster) is considered. It is shown that, unlike a phase raster with a mechanical drive, a digital raster provides the possibility of automation and increased measurement accuracy, reducing the weight and size characteristics of the measuring instrument. A method for constructing a digital raster is proposed, based on the use of photomatrices in combination with computer technologies. To ensure the required accuracy of the developed opto-electronic devices, the sources and components of the measurement error were investigated. The influence of the discrete structure of a digital raster on the error in measuring image coordinates has been studied. Mathematical expressions are obtained for calculating the limiting values of coordinate measurement errors caused by parasitic phase modulation that occurs when using a digital raster (sampling error). The dependence of these errors on image parameters and pixel size has been determined. It is shown that, based on the permissible maximum sampling error, it is possible to calculate the required dimensions of a photomatrix pixel, while the size of the sampling pixel can be larger than the size of the photomatrix pixel, which is very signifi cant from the point of view of energy relations. The results obtained will be useful in the development of optical-electronic means of angular and linear measurements with digital rasters.

The issues of increasing hydrodynamic efficiency, improving the operational and technical characteristics of various apparatus and devices used in the fi eld of heat and mass transfer, as well as ensuring the required regime and flowow conditions of liquids of different viscosities do not lose their relevance. To solve these issues, in addition to studying the nature of the flowow of various liquids in round horizontal tubes (capillaries), it is necessary to determine the conditions when the flowow of liquid in capillaries and round tubes of small diameter is laminar and can be described by the Poiseuille equation. Experimental data on determining water flow ow through horizontal round tubes of various diameters are presented. Determining the patterns and features of such flow ows is mostly aimed at increasing hydrodynamic efficiency, improving the operational and technical characteristics of various apparatus and devices, as well as ensuring the required flow ow regime and conditions. Experimental data on determining the flow ow rate of water through horizontal tubes of circular cross-section with different diameters are presented in the article. The dependence of the volumetric flow ow rate on the pressure drop has been determined; it has been shown that the main parameters that determine the nature of the flow ow of liquids in horizontal tubes are the tube radius and the dynamic viscosity of the liquid. The flow ow of distilled water in tubes with diameters of 0.95, 1.6 and 2.0 mm at an overpressure of 0.266 kPa to 4 kPa is considered. It is shown that the dependence of the volumetric flow ow rate on the excess pressure remains linear at 0.95 mm in the entire considered pressure range. An increase in the tube radius increases the likelihood of velocity flow uctuations and the appearance of a radial velocity component, i.e. the occurrence of elements of a turbulent structure. In this regard, with tube diameters of 1.6 and 2.0 mm, a deviation of the water flow ow regime from the laminar character was established at pressures of more than 1.3 kPa and 1 kPa, respectively. The dependence of the volumetric flow ow rate on pressure for a 40 % aqueous solution of CaCl2, transformer, transmission and engine oils with dynamic viscosity coefficients from 0.002 Pa·s to 0.182 Pa·s remains linear up to pipe diameters of 5–6 mm. The experimental results are shown in the form of a nomogram of the dependence of the coefficient K* on the tube radius at different values of the viscosity coefficient. The results of studies of liquids of various viscosities are presented in the form of a nomogram of the dependence of the ratio of the radius of the tube to the fourth power to the viscosity of the liquid on the radius of the tube. The analysis of which makes it possible to predict the nature of the flow ow of the investigated liquid at the given values of the tube radius and the dynamic viscosity coefficient. Heat exchange devices for the design of which the presented results can be used include a variety of radiators that include tubes through which coolant circulates.

Features of methods practical use for material dielectric properties measurement in different (factory and metrological) laboratories and influence of above mentioned features on measurements results are considered. Results are obtained by Obninsk Research and Production Enterprise “Technologiya” A. G. Romashin radiophysics laboratory and by East-Siberian branch Federal State Unitary Enterprise “Russian metrological institute of technical physics and radio engineering” department of radio engineering measurements. Results of microwave permittivity and loss tangent solid materials measurements are analysed. This investigation made it possible to get additional information about features of standard methods practical use for material dielectric properties measurement, which was absent in literature earlier. In laboratories for measurements used the waveguide resonator and the standardized techniques. The factory laboratory applied a measurement method at the fixed frequency with control in a resonance movement of the plunger, and in metrological laboratory a measurement method with the fixed length of the resonator and measurement at resonant frequencies. Results of measurements showed good reproducibility of results for samples that are meeting method requirements. It was revealed reducing reproducibility of measurements of hygroscopic, heterogeneous samples and in the case of nonobservance of diameter method requirements. Obtained results can be applied for reproducibility improvement of dielectric properties measurements in practical use of considered methods.

The task of analyzing a glottal source over a short observation interval is considered. The acute problem of insufficient performance of known methods for analyzing a glottal source is pointed out, regardless of the mode of data preparation: synchronous with the main tone of speech sounds or asynchronous. A method for analyzing the glottal source based on a two-level autoregressive model of the speech signal is proposed. Its software implementation based on the high-speed Burg-Levinson computational procedure is described. It does not require synchronization of the sequence of observations used with the main tone of the speech signal and is characterized by a relatively small amount of computational costs. Using the described software implementation, a full-scale experiment was set up and conducted, where the vowel sounds of the control speaker’s speech were used as the object of study. Based on the results of the experiment, the increased performance of the proposed method was confirmed and its requirements for the duration of the speech signal during voice analysis in real time were formulated. It is shown that the optimal duration is in the range from 32 to 128 ms. The results obtained can be used in the development and research of digital speech communication systems, voice control, biometrics, biomedicine and other speech systems where the voice characteristics of the speaker’s speech are of paramount importance.

The article analyzes types of measurement procedures and procedures for transferring a unit of quantity, such as: primary reference measurement procedures, reference measurement procedures, calibration procedures, validation procedures, end-user measurement procedures and measurement procedures. The article discusses requirements for developing the presented procedures, their research and approval. The article presents a classification of procedures depending on their place in metrological traceability chain, type of determined metrological characteristics and their application in the field of regulation. Based on the results of the analysis of regulatory documents, a table that describes basic requirements for development and approval of measurement procedures and procedures for transferring a unit of quantity is presented. The article also discusses requirements established for conformity assessment procedures for measurement procedures and procedures for transferring а unit of quantity, such as certification, validation and verification of procedures. The article presents definitions and scope of application for conformity assessment of measurement procedures and procedures for transferring a unit of quantity. Based on the analysis of requirements for conformity assessment of procedures, a flowchart for selecting appropriate conformity assessment procedure is presented. Due to this scheme, laboratories will be able to unambiguously choose one or another conformity assessment procedure to approve the required measurement method or method of transferring a unit of value. In particular, in preparation for accreditation for compliance with the requirements of ISO/IEC 17025-2017 “General requirements for the competence of testing and calibration laboratories.” The proposed scheme of choosing a procedure for conformity assessment of a specific measurement procedure eliminates ambiguity of the requirements of regulatory documents.