Metrological assurance of immunity tests to impulse currents of natural and artificial origin is an urgent task in the development and production of aviation, rocket and space equipment and telecommunication equipment. The State primary special standard of lightning discharge impulse current unit GET 202-2012 provided the unity of measurements of impulse current parameters in the amplitude range from 1 to 100 kA and the time range from hundreds of nanoseconds to units of milliseconds. In order to provide metrological support for measuring instruments for impulse currents of electrostatic discharges and switching currents (rise time of the transient response of at least 1 ns, measurement range from 1 to 200 A), GET 202-2012 underwent a modernization cycle in 2020–2023. As a result of the modernization, the State Primary Special Standard of the unit of pulse current in the range from 1.0 to 1.0·10⁵ A GET 202-2024 was approved, the lower limit of the range of reproduction of the unit of pulse current of which was 1 A with a pulse front duration of no more than 1 ns. Thus, the problem of ensuring the uniformity of measurements of electrostatic discharges and power switching impulse currents parameters was solved. To achieve the specified characteristics, GET 202-2024 includes devices for reproducing current pulses based on semiconductor keys and reference current shunts with a short rise time. The composition, structural diagram, technical and metrological characteristics of GET 202-2024 are given. GET 202-2024 ensures the uniformity of measurements of the parameters of pulse currents of electrostatic discharges, partial lightning discharges, as well as pulse currents generated by switching processes when solving problems of electromagnetic compatibility, creating new types of materials and coatings, in geophysical and meteorological research and observations, in healthcare.

The problem of ensuring the accuracy and traceability of the measurement results of the absorbed dose in carbon ion beams, as well as the measurement results of the amount, fluence, flux density and energy of particles in proton and heavy charged particles beams is considered. Until now, in practice, these values have been measured only by indirect methods. The lack of approved measuring instruments for the quantities under consideration and the metrological traceability of measurement results of these quantities to standards did not allow achieving consistency of measurement methods used in practice and confirming the reliability of the results obtained. To solve this problem, three measuring complexes have been developed and created, which are included in the State Primary Standard of units of absorbed dose and absorbed dose rate of photon, electron, proton radiation and in carbon ion beams, quantity, fluence, flux density and energy of particles in proton and heavy charged particles beams GET 38-2024. The measuring complex for reproducing the unit of absorbed dose in carbon ion beams consists of an adiabatic calorimeter, a thermostating system, a data collection and processing system and a vacuum pumping station. To reproduce the unit of energy of protons and heavy charged particles, a complex has been implemented, which includes a total absorption calorimeter, a data collection and processing system, a vacuum pumping station and a particle count determination system based on the use of a Faraday cup. To reproduce the units of fluence and particle flux density in proton and heavy charged particles beams, a measuring complex has been created containing a Faraday cup, a set of collimators and a low current meter. The schemes, the principles and the results of studies of the metrological characteristics of the developed measuring complexes are described. The results are relevant for the field of radiation therapy and radiation resistance tests of the electronic component base used in the space industry.

The discharge coefficient of flow transducers of liquids and gases of differential pressure flowmeters plays an important role in flow rate measurement. The problem of modeling and calculating the discharge coefficient of differential pressure flowmeters directly affects the accuracy of flow rate measurement of these devices. The results of modeling the discharge coefficient of the differential pressure flowmeter in the form of radial-basis neural networks are presented. The described structure of the neural network calculates the values of the discharge coefficient with an angular pressure tapping method. The article evaluates the error of approximation of the discharge coefficient by radial-basis function networks and provides recommendations for building such networks to solve problems of modeling the characteristics of differential pressure flowmeters. The article discusses the main advantages and disadvantages of using such networks as discharge coefficients of the differential pressure flowmeters. The research showed that the use of such networks is justified by their properties to approximate the discharge coefficient and their efficiency in measuring gas and liquid flow rates.

Spectrophotometric methods for studying the composition of mixtures are considered. The need to increase the stability and accuracy of the results of spectrophotometric measurements when analyzing substances with low absorption coefficients or a low concentration of the determined substance is shown. A spectrophotometric complex with a thermostated cell is described, which enables to study gaseous and liquid mixtures. Results of study at this complex of absorption spectra of isomers of liquid xylene and their mixtures are given. Methods of increasing the stability of spectrophotometric measurement results, hardware and data processing methods necessary for this are considered. It has been shown that thermostating of not only vaporous, but also liquid samples is one of the necessary conditions for ensuring the stability of measurement results. The procedure for performing experiments and processing the results of spectrophotometric measurements is presented. A differential method has been developed to reduce the impact of spectrophotometer signal instabilities on the accuracy of determining the composition of mixtures. The method consists in using as input data for multiple linear regression not the absorption spectrum, but its wavelength derivative. An analysis of the composition of mixtures of two xylene isomers showed that the use of this method can reduce RMS of determining the composition of mixtures by about 1.6 times. It is noted that additional filtering (smoothing) of the measured absorption spectrum derivative may be required to reduce errors in determining the composition of mixtures. The developed method of reducing the influence of the spectrophotometer signal instabilities on the results of the mixture composition analysis is of the greatest interest for the analysis of substances with low absorption coefficients or in the case of low concentrations of the studied substances and can be used to solve environmental monitoring problems, for example, when determining hydrocarbon contaminants in the atmosphere.

An important characteristic of a national time scale is its deviation from the Coordinated Universal Time (UTC) scale. The emergence of the Rapid Coordinated Universal Time scale (UTCr) offers the potential to form national time scales that closely follow UTC with high accuracy. Information on the deviations of national time scales in Rapid UTC is updated weekly. In this case, it becomes possible to use more cost-effective atomic clocks with greater frequency instability compared to the active hydrogen masers currently employed in leading timekeeping metrology laboratories. The feasibility of using the Rapid Coordinated Universal Time scale (UTCr) to implement a national time scale based on passive hydrogen masers with high UTC tracking accuracy is demonstrated using the example of the national Coordinated Universal Time scale of Kazakhstan, UTC(KZ). The results of the automatic steering system for the UTC(KZ) time scale based on the Rapid UTC data, published by the International Bureau of Weights and Measures, are presented. The steering algorithm is described, and its parameters are justifi ed. It is shown that a time scale based on passive hydrogen masers, with weekly corrections from Rapid UTC data, achieves a root mean square error (RMSE) of 2.5 ns and a maximum deviation of less than 8 ns over a two-year observation period.

The issues of testing magnetic flowmeters for liquid metal and studies of their metrological characteristics are considered. The existing liquid metal pouring flowmeters are unsuitable for experimental studies of error components, therefore it is necessary to use simulation methods to simulate the operation of magnetic flowmeters. The tests require the liquid metal plants or methods that allow you to examine flowmeters without plants that can reproduce the flow rate in various operating modes. By analogy with the simulation method of water flowmeters research, a simulation method for modeling the operation of magnetic flow meters for liquid metals has been developed. The proposed method estimates the error of magnetic flowmeters in operation mode. The components of the measurement error of flowmeters caused by a violation of the geometry of the primary converter (the size and location of the electrodes, the design of the inductor coils), a change in the hydrodynamic regime, and the temperature dependence of the shunting effect of the pipeline wall are considered. A representation is obtained for the signal of the primary converter in the form of an integral over the inner surface of the pipe from the product of the radial component of the magnetic field and the surface weight function. The expression found can be interpreted as a magnetic flux through an induction coil located on the inner surface of the channel, the turns of which are drawn along the level lines of the surface weight function. This expression can be interpreted as a magnetic flux through an induction coil located on the inner surface of the channel, the coils of which are placed along the lines of the level of the surface weight function. If such a coil is inserted in the flowmeter channel, the time-integrated voltage induced in the coil will be proportional to the voltage generated between the electrodes of the flowmeter. Since the surface weight function depends on the geometry of the channel, the kinematic structure of the flow, the ratio of wall and liquid conductivities, therefore, the metrological characteristics of the flowmeter can be studied by the simulation method when each of the above factors changes individually or together. To do this, it is enough to make an induction coil taking into account the surface weight function that reflects any of the factors under study or their combination. Simulation methods for studying the dependences of magnetic flowmeter signals on the velocity distribution in the channel and the shunting effect of the pipeline wall are considered.

Methods for early non-invasive diagnosis of melanoma using computer vision systems are considered. Existing computer vision systems using neural networks for classifying dermoscopic images do not allow tracking which diagnostic features are used to assign images to a particular class, reducing physicians' trust in the results. As an alternative, an image analysis algorithm is proposed with the ability to present justifications for decisions made at each processing stage. The implementation of this algorithm is based on the medical algorithm of modified globular pattern analysis. A significant sign of malignancy in a neoplasm is its asymmetry. This criterion is widely used by doctors in visual assessment of skin neoplasms. However, currently, the issues of evaluating the symmetry of globular patterns in artificial intelligence systems are not fully studied and described. A method for evaluating the symmetry of globular patterns in artificial intelligence systems for diagnosing skin neoplasms has been developed. A dataset of dermoscopic images was formed, containing 50 images each of neoplasms with symmetrically and asymmetrically arranged globular patterns. Methods for isolating the neoplasm area and globules are described. A classification system based on a set of 12 quantitative symmetry characteristics has been developed. The Random Forest algorithm was used to classify images based on symmetry features. In the conducted experiment, a classification accuracy of 85% was achieved. The presented results contribute to the development of computer vision methods in dermatology and demonstrate the possibility of using the proposed method in clinical decision support systems for modified analysis of dermoscopic patterns for diagnosing skin neoplasms.

The article considers flight safety issues related to continuous monitoring of the pilot's functional state by using means of monitoring physiological health indicators, which is due to the complexity of flight work, accompanied by a whole range of unfavorable factors that reduce the efficiency of professional activity. The article studies the influence of the general vibration factor on the quality (accuracy) of the assessment of the pilot's physiological indicators recorded by non-invasive diagnostic devices in transmitted light. Such indicators include heart rate, fractional blood saturation level, and respiratory rate. A mathematical model of quasi-deterministic general vibration, which is the resultant of individual frequency components of corrected vibration acceleration directed along three axes of the Cartesian coordinate system, has been developed. Mathematical modeling of the effect of general vibration on the information photoplethysmographic signal has been performed and it has been shown that the effect changes the frequency-time structure of the signal and relative errors of the estimated physiological parameters appear – the level of fractional blood saturation (4.16 %), heart rate (4.78 %) and respiration (3.75 %). As a result of a practical experiment to analyze the effect of general vibration on the quality of assessment of the specified physiological parameters, it was found that, compared to the declared error of a pulse oximeter of ±2 %, the errors in determining the heart rate, fractional blood saturation and respiration rate increased by 3.221 %; 2.483 % and 1.906 %, respectively. The results of theoretical and practical studies have a strong pair correlation according to Pearson, the pair correlation coefficients were 0.72, 0.83, 0.76 for the results of measurements of heart rate, fractional blood saturation level and respiratory rate, respectively, which indicates the validity of the adopted simplifi ations in the development of the mathematical model. The obtained results can be used to develop devices for non-invasive diagnostics of the pilot's physiological indicators, functioning directly during the flight.