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A. R. Bayev, A. L. Mayorov, N. V. Levkovich, D. V. Shavlovskiy, M. V. Asadchaya
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-2-124-132

Abstract:
The improvement of efficiency, reliability and productivity of ultrasonic testing of objects with cohesion between materials connected by welding, soldering, gluing, etc. is 'an important problem of the modern production technologies. The purpose of the paper is to determine in 3D space the conditions for increasing the sensitivity and reliability of the flaw detection in the cohesion zone between materials when the form of defect interface can be different. In the first part of the theoretical study the features of the formation of the acoustic fields of ultrasonic waves scattered from solid's interface when spot of an acoustic beam crosses the boundary of the defective region in the shape of an ellipse or a long strip have been investigated. In this case, the boundary conditions in the defect area change discretely or linearly. It was suggested to use a phase shift between reflected waves from the defect and defect-free interfaces as the more informative parameter depending on the cohesion between materials. There is shown that there are conditions to achieve sufficiently high sensitivity detection of interface defects when the scattered waves receiving are to be at angles outside the main directivity lobe of the scattering field pattern. The evolution features of the scattering field structure which are needed for the development of the method of evaluation the cohesion of materials has been got.
G. A. Gusakov,
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-2-139-145

Abstract:
Improving the technology of diamond turning of aluminum alloys is of great importance for expanding the application areas of metal-optical products based on aluminum in aerospace technology. The aim of this work was to study the effect of surface inhomogeneities of the initial aluminum alloy substrates on their optical and mechanical characteristics and to determine ways of improving the quality of aluminum reflector mirrors manufactured using nanoscale single point diamond turning. The investigated reflector mirrors were made from AMg2 aluminum alloy. The optical surface treatment was carried out on a precision turning lathe with an air bearing spindle using a special diamond cutter with a blade radius of ≤ 0.05 μm. The analysis of the surface structure of the AMg2 alloy substrates was carried out by scanning electron microscopy / electron microprobe. The quality control of the surface treatment of the manufactured reflector mirrors was carried out by atomic force microscopy. The reflectivity and radiation resistance of these samples were also investigated. It is shown that an important problem in the manufacture of optical elements from aluminum alloys is the inhomogeneity of the structure of the initial material, associated with the presence of intermetallic inclusions. Heat treatment of the AMg2 alloy substrates at T ≥ 380 °C makes it possible to improve the quality of surface and the radiation resistance of aluminum mirrors both by removing mechanical stresses and by partially homogenizing the starting material. The optimum is heat treatment at the maximum allowable temperature for the AMg2 alloy T = 540 ºС, as a result of which there is a complete disappearance of intermetallic inclusions with an increased magnesium content. The use of high-temperature heat treatment of AMg2 alloy substrates allows, in comparison with unannealed samples, to reduce the surface roughness from 1.5 to 0.55 nm, to increase the reflectivity of mirrors at a wavelength of 1064 nm from 0.89 to 0.92, and to increase the laser damage threshold from 3.5 to 5 J / cm2.
S. A. Tikhomirov
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-1-23-29

Abstract:
For several decades development of methods for generating ultrashort pulses has been an independent urgent scientific and technical problem. There is a constant improvement both in the methods of such pulses receiving and in methods of their use. The aim of this work was to investigate the possibility of realizing the coordinated operation of two fundamentally different types of pump lasers for the femtosecond oscillator and amplifier based on one single-lamp laser head and to create on this basis a compact high-power femtosecond system with pulsed pumping and one power unit. The practical implementation of two types of pulsed lasers (nano- and picosecond ones operating, respectively, in Q-switch and modelock regime) on a single laser head with two active elements and one pump lamp is carried out. The required synchronization in time the pump pulse femtosecond amplifier formation and quasi-stationary region of generated pulses in the output radiation of a femtosecond Ti:sapphire is obtained. On this basis a compact, pulse pumped monoblock laser system has been developed that can generate femtosecond pulses with a duration of 50–150 fs with an energy up to 1 mJ and a high enough pulse repetition rate (up to 1 kHz which is determined by the type of laser head and pump unit used). In the developed laser system a compact scheme of a stretcher-compressor with a single common diffraction grating is used. Laser systems of this type characterized by a relatively low cost due to the use of a single power supply unit for simultaneous pumping of the amplifier and oscillator, as well as lower requirements for the quality of optical elements and usage conditions due to the pulse mode of operation, are quite practical and can be used both in scientific research in the field of ultra-high-speed kinetic spectroscopy and nonlinear optics, as well as in numerous technical applications, particular in the precision processing of materials, as optical simulators of the action of heavy charged particles in testing the radiation resistance of integrated circuits and electronic modules.
A. A. Adnastarontsau, D. A. Adnastarontsava, R. V. Fiodortsev, D. V. Katser, A. Y. Liavonau, D. V. Romanov, D. N. Tcherniakovski, A. О. Mikhailau
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-1-46-57

Abstract:
The purpose of the research was to create an algorithm for determining and correcting the output parameters of the navigation module and the flight-navigation complex of unmanned aerial vehicles which provides control of an aviation gyro-stabilized platform with a multispectral optoelectronic system during flight and tracking various objects of observation. Principles of control of an aviation technical vision system located on an unmanned aerial vehicle on a two-degree gyro-stabilized platform with the possibility of full turn around two perpendicular axes along the course and pitch are considered. Stability of tracking of observation objects at a distance of up to 10000 m is ensured by the use of a multispectral optoelectronic system including a rangefinder, thermal imaging and two visual channels. Analysis of the object of observation and the method of its support are carried out. An algorithm is proposed for integrating a Global Navigation Satellite System and a strapdown inertial navigation system based on the extended Kalman filter which includes two stages of calculations, extrapolation (prediction) and correction. Specialized software in the FreeRTOS v9.0 environment has been developed to obtain a navigation solution: latitude, longitude and altitude of the unmanned aerial vehicle in the WGS-84 coordinate system, as well as the pitch, heading and roll angles; north, east and vertical components of velocities in the navigation coordinate system; longitudinal, vertical and transverse components of free accelerations and angular velocities in the associated coordinate system based on data from the receiving and measuring module of the Global Navigation Satellite System and data from the 6-axis MEMS sensor STIM300.
Н. А. Поклонский, S. A. Vyrko, A. I. Kovalev, I. I. Anikeev, N. I. Gorbachuk
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-1-13-22

Abstract:
The study of thermoelectric properties of crystalline semiconductors with structural defects is of practical interest in the development of radiation-resistant Peltier elements. In this case, the spectrum of energy levels of hydrogen-like impurities and intrinsic point defects in the band gap (energy gap) of crystal plays an important role. The purpose of this work is to analyze the features of the single-electron band model of semiconductors with hopping electron migration both via atoms of hydrogen-like impurities and via their own point triplecharged intrinsic defects in the c- and v-bands, as well as to search for the possibility of their use in the Peltier element in the temperature range, when the transitions of electrons and holes from impurity atoms and/or intrinsic defects to the c- and v-bands can be neglected. For Peltier elements with electron hopping migration we propose: (i) an h-diode containing |d1)and |d2)-regions with hydrogen-like donors of two types in the charge states (0) and (+1) and compensating them hydrogen-like acceptors in the charge state (−1); (ii) a homogeneous semiconductor containing intrinsic t-defects in the charge states (−1, 0, +1), as well as ions of donors and acceptors to control the distribution of t-defects over the charge states. The band diagrams of the proposed Peltier elements in equilibrium and upon excitation of a stationary hopping electric current are analyzed. A model of the h-diode containing hydrogen-like donors of two types |d1) and |d2) with hopping migration of electrons between them for 50 % compensation by acceptors is considered. It is shown that in the case of the reverse (forward) electrical bias of the diode, the cooling (heating) of the region of the electric double layer between |d1)and |d2)-regions is possible. A Peltier element based on a semiconductor with point t-defects is considered. It is assumed that the temperature and the concentration of ions of hydrogen-like acceptors and donors are to assure all t-defects to be in the charge state (0). It is shown that in such an element it is possible to cool down the metal-semiconductor contact under a negative electric potential and to heat up the opposite contact under a positive potential.
M. A. Kuznetsov, D. P. Ilyaschenko, A. V. Kryukov, S. A. Solodsky, E. V. Lavrova, E. V. Verkhoturova
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-1-38-45

Abstract:
Modeling of velocities and temperatures processes distribution in the plasma-forming channel determining the design features and optimal parameters of the plasma torch nozzle is one of promising directions in development of plasma technologies. The aim of this work was to simulate the processes of velocities and temperature distribution in the plasma-forming channel and to determine the design features and optimal geometric parameters of the plasmatron nozzle which ensures the formation of necessary direction of plasma flows for generation of surface waves on the surface of a liquid metal droplet under the influence of the investigated instabilities. One of the main tasks is to consider the process of plasma jet formation and the flow of electric arc plasma. For obtaining small-sized particles one of the main parameters is the plasma flow velocity. It is necessary that the plasma outflow velocity be close to supersonic. An increase of the supersonic speed is possible due to design of the plasmatron nozzle especially the design feature and dimensions of the gas channel in which the plasma is formed. Also the modeling took into account dimensions of the plasma torch nozzle, i. e. the device should provide a supersonic plasma flow with the smallest possible geometric dimensions. As a result models of velocities and temperatures distribution in the plasma-forming channel at the minimum and maximum diameters of the channel were obtained. The design features and optimal geometric parameters of the plasmatron have been determined: the inlet diameter is 3 mm, the outlet diameter is 2 mm. The design of the executive equipment has been developed and designed which implements the investigated process of generating droplets of the micro- and nanoscale range. A plasmatron nozzle was manufactured which forms the necessary directions of plasma flows for the formation of surface waves on the metal droplet surface under the influence of instabilities. An algorithm has been developed for controlling of executive equipment that implements the process of generating drops of micro- and nanoscale range.
O. D. Kanafyev, A. V. Trukhanov, Т. И. Зубарь, S. A. Chizhik, S. S. Grabchikov
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-1-30-37

Abstract:
Optimization of the radiation coil of the hardware-software complex for studying the effectiveness of shielding of low-frequency electromagnetic radiation will make it possible to assess the effectiveness of shielding coatings at a higher level. This fact will make it possible to develop coatings with improved characteristics. The purpose of this work was to determine the optimal characteristics of the emitting coil which will ensure its stable operation and magnetic field strength in the frequency range up to 100 kHz. The parameters of the manufactured samples, such as inductance (L), active (R) and total resistance (Z), were obtained using an MNIPI E7-20 emittance meter. In practice, the coils with the optimal parameters calculated theoretically were connected to a current source and amplifier. To detect electromagnetic radiation, a multilayer inductor connected to a UTB-TREND 722-050-5 oscilloscope was used as a signal receiver. The results of measurements showed that the resistance of multilayer coils is approximately 1000 times higher than that of single-layer coils. Also, for multilayer coils, an avalanche-like increase in total resistance is observed starting from a frequency of 10 kHz, while for single-layer coils there is a uniform increase in total resistance over the entire frequency range up to 100 kHz. The paper presents results of research on the correlation of the performance of single-layer and multilayer inductors depending on their parameters in the frequency range from 20 Hz to 100 kHz. Values of the voltage required to provide the magnetic field strength of 1, 5, 20 Oe at 25 Hz and 100 kHz have been calculated. After analyzing the data obtained, the optimal parameters of the inductor were found which ensure stable performance in the frequency range up to 100 kHz.
, D. A. Borisevich
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-1-75-81

Abstract:
The aim of the work was a multivariate calibration of the concentration of unrefined sunflower oil, considered as adulteration, in a mixture with flaxseed oil. The relevance of the study is due to the need to develop a simple and effective method for detecting the falsification of flaxseed oil which is superior in the content of essential polyunsaturated fatty acids to olive oil. A few works only are devoted to identifying adulteration of flaxseed oil, unlike olive oil.Multivariate calibration carried out using a model based on the principal component analysis, cluster analysis and projection to latent structures of absorbance spectra in UV, visible and near IR ranges. Calibration uses three methods for spectral variables selection: the successive projections algorithm, the method of searching combination moving window, and method for ranking variables by correlation coefficient.The application of the successive projections algorithm, ranking variables by correlation coefficient and searching combination moving window makes it possible to reduce the value of the root mean square error of prediction from 0.63 % for wideband projection to latent structures to 0.46 %, 0.50 %, and 0.03 %, respectively.The developed method of multivariate calibration by projection to latent structures of absorbance spectra in UV, visible and near IR ranges using the spectral variables selection by searching combination moving window is a simple and effective method of detecting adulteration of flaxseed oil.
O. P. Bogdan, D. V. Zlobin, O. V. Murav'Eva, S. M. Molin, A. V. Platunov
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-1-58-66

Abstract:
The widespread use of polyolefin foams in strategically important industries is due to their high thermal, sound and vibration insulation properties. The aim of the work was to evaluate the non-uniformity of elastic properties over the area of sheets of polyolefin foams of various types using the acoustic non-contact shadow amplitude method of testing and confirmation by the structural analysis method. The article presents the developed installation and a new method of non-contact acoustic testing of sheets made of closed-cell polyolefin foams based on recording the amplitude of the pulse that passed through the sheet and allowing to assess to the unevenness of its elastic properties during scanning. Studies of uneven elastic properties were carried out on sheets of closed-cell polyolefin foams of the ISOLON 500 and ISOLON 300 brands which differ in material and manufacturing technology (technique of cross-linking, method and multiplicity of foaming). It is shown that the absolute amplitude of the signal and its spread relative to the average value is affected by the structure of the foam polyolefin material and its heterogeneity over the area of the studied sheet determined by the production technology which is confirmed visually using microscopy. Studies have shown the effect on the indications unevenness of the method of obtaining and the apparent density of the material. It is shown that the most uneven elastic properties and structure belong to sheets of polyolefin foam obtained by chemical cross-linking technology (the unevenness of Δ was 6.5 %). Among the physically cross-linked sheets of polyolefin foam the most uniform in structure and elastic properties are samples made of ethylene vinyl acetate with Δ = 3.8 %, as well as sheets with a high foaming rate (Δ = 3.9 %). The unevenness of structure of the studied sheets of polyolefin foams was confirmed by optical microscopy of sections in two mutually perpendicular directions.
I. A. Konovalov, A. A. Chesnokov, A. A. Barinov, S. M. Dmitriev, A. E. Khrobostov, M. A. Legchanov, S. S. Borodin, M. A. Makarov
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-1-67-74

Abstract:
The correlation method of the coolant flow measuring is widely used in research practice including for studying of turbulent coolant flows in scale models of elements of nuclear power plants. The aim of this work was to develop a technique for assessing the effect of noise recorded by a measuring system on the flow rate readings obtained using the correlation method. A technique to assess the effect of noise as well as the relative position and acquisition period of sensors is presented. An insignificant concentration of a salt solution (NaCl or Na2SO4 ) is used as a passive impurity which creates a conductivity gradient of the medium recorded by a conductometric system. Turbulent pulsations at the interface between two concurrent isokinetic flows in a channel with a square cross section are used as the signal source for the correlational algorithm. Paper presents the values of the turbulence′s transport time between spatial conductometers, the results of estimating the spectral power density and band of the recorded signal and also the signalto-noise ratios of the measuring system obtained on their basis which are subsequently used to estimate the confidence interval of the transport time. As a result of measurements the relationship between the confidence interval value and the signal length were obtained. The measurements which were carried out at different relative positions of conductometers make it possible to make a conclusion about an increase in the spectral width of the signal and, as a consequence, a decrease in the length of the confidence interval with increasing of distance between sensors. The presented work is an approbation of this approach for its application as part of an experimental model of a nuclear reactor in order to determine per-channel flow rates in the channels of the core simulator using mesh conductometric sensors taking into account the effect of noise.
Devices and Methods of Measurements, Volume 12; https://doi.org/10.21122/2220-9506-2021-12-1-7-12

Abstract:
The permanent magnetic field in addition to electromagnetic radiation has a significant effect on performance of devices. This is particularly true for highly sensitive precision measuring equipment, such as, for example, magnetometers or photomultiplier tubes. In this regard a new high-performance materials for protection against permanent fields and electromagnetic radiation need to be developed. The purpose of this paper is a development of a hardware and software complex for high-precision determination of permanent magnetic field attenuation coefficient and certification of protective materials. This paper describes an experimental installation for determining the attenuation coefficient of a permanent magnetic field using materials and coatings on standard package for electronic equipment. The installation ensures a uniform magnetic field flow in the measurement volume. The advantage of the measuring device is the ability to measure magnetic field in three coordinates due to the use of three pairs of Helmholtz coils and a three-dimensional Hall sensor. The software will enable to control of the magnetic field in all three directions, simulating the real operating conditions of devices that require protection from such influences. In addition, a movable positioning system makes it possible to compensate for the Earth's magnetic field, which increases the accuracy of estimating the attenuation coefficient by protective materials in weak magnetic field. An alternative use of the capabilities of the installation is to test the performance of the devices in a permanent magnetic field and evaluate the electromagnetic compatibility. Experimental results of the work includes determination of the magnetic field attenuation coefficient using standard photomultiplier tube package made of electrolytically deposited permalloy and the sheet of annealed permalloy. Thus, the effect of annealing and closed magnetic circuit on the degree of weakening of the magnetic field is shown. It has been demonstrated that annealing which causes a significant increase in the magnetic permeability promotes an effective attenuation of weak magnetic fields (up to 1 mT). In magnetic fields with an induction of 1 mT or more, effective attenuation is provided by a closed magnetic circuit.
E. V. Titovich, M. N. Piatkevich, N. I. Makarava
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-4-289-297

Abstract:
One of the main factors affecting the effectiveness of radiation therapy is the constancy of the patient’s position on the treatment table created by immobilization devices of various designs and held throughout the entire irradiation procedure, which guarantees the accuracy of the delivery of the prescribed dose distribution. The purpose of the work was to establish the numerical values of the dominant components of a radiation therapy session for each of the irradiation techniques most commonly used in clinical practice of the radiation therapy.To determine the numerical values of the components of the radiation therapy session, the authors have measured each component for some clinical cases of patients’ irradiation placed. The patients had been diagnosed with the following malignant tumours: prostate cancer, breast cancer, lung cancer, head and neck tumours. More than 2000 individual measurements have been carried out with the help of such medical linear accelerators as "Clinac", "Unique", "Truebeam", and the gamma-therapeutic apparatus named "Theratron".The numerical values of the time spent on 3 groups of parameters of an irradiation session were established: the mechanical parameters of the radiation therapy equipment, the functional characteristics of the irradiation systems and the parameters that directly depend on the personnel involved in an irradiation procedure.According to the measurement results, the flow diagram for the procedures of verifying a patient’s position on the therapeutic table (2 different techniques), preceding their irradiation and the radiation therapy procedures themselves was proposed. It has been shown that a number of session components can run in parallel to each other thus optimizing the time spent by a patient in the treatment room.Using the obtained values of the time spent on the radiation session parameters it is possible to actualize the mathematical model that will allow the medical physicist to determine in advance the duration of the irradiation session at the stage of treatment planning and choose a radiation therapy technique taking into account the individual parameters of the irradiation session in each particular clinical case.
V. N. Mishchenka
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-4-298-304

Abstract:
The use of graphene, which has high mobility of charge carriers, high thermal conductivity and a number of other positive properties, is promising for the creation of new semiconductor devices with good output characteristics. The aim was to simulate the output characteristics of field effect transistors containing graphene using the Monte-Carlo method and the Poisson equation.Two semiconductor structures in which a single layer (or monolayer) of graphene is placed on a substrate formed from 6H-SiC silicon carbide material are considered. The peculiarity of the first of them is that the contact areas of drain and source were completely located on the graphene layer, the length of which along the longitudinal coordinate was equal to the length of the substrate. The second structure differed in that the length of the graphene layer was shortened and the drain and source areas were partly located on the graphene layer and partly on the substrate.The main output characteristics of field-effect transistors based on the two semiconductor structures considered were obtained by modeling. The modeling was performed using the statistical Monte Carlo method. To perform the simulation, a computational algorithm was developed and a program of numerical simulation using the Monte-Carlo method in three-dimensional space using the Poisson equation was compiled and debugged.The results of the studies show that the development of field-effect transistors using graphene layers can improve the output characteristics – to increase the output current and transconductance, as well as the limit frequency of semiconductor structures in high frequency ranges.
V. F. Petryk, A. G. Protasov, R. M. Galagan, A. V. Muraviov, I. I. Lysenko
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-4-272-278

Abstract:
Currently, non-destructive testing is an interdisciplinary field of science and technology that serves to ensure the safe functioning of complex technical systems in the face of multifactorial risks. In this regard, there is a need to consider new information technologies based on intellectual perception, recognition technology, and general network integration. The purpose of this work was to develop an ultrasonic flaw detector, which uses a smartphone to process the test results, as well as transfer them directly to an powerful information processing center, or to a cloud storage to share operational information with specialists from anywhere in the world.The proposed flaw detector consists of a sensor unit and a smartphone. The exchange of information between the sensor and the smartphone takes place using wireless networks that use "bluetooth" technology. To ensure the operation of the smartphone in the ultrasonic flaw detector mode, the smartphone has software installed that runs in the Android operating system and implements the proposed algorithm of the device, and can serve as a repeater for processing data over a considerable distance (up to hundreds and thousands of kilometers) if it necessary.The experimental data comparative analysis of the developed device with the Einstein-II flaw detector from Modsonic (India) and the TS-2028H+ flaw detector from Tru-Test (New Zealand) showed that the proposed device is not inferior to them in terms of such characteristics as the range of measured thicknesses, the relative error in determining the depth defect and the object thickness. When measuring small thicknesses from 5 to 10 mm, the proposed device even surpasses them, providing a relative measurement error of the order of 1 %, while analogues give this error within 2–3 %.
A. G. Anisovich
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-4-279-288

Abstract:
Grain size is one of the most important characteristics of the microstructure of metals and alloys. Determination of the grain size of steel is regulated by Standart 5639-82 "Steels and alloys. Methods for detection and determination of the grain size". Standart includes determining the grain score by comparison with reference scales, as well as manual measurement methods. The use of image processing software opens up new opportunities for the materials analysis, including for the quantitative metallographic analysis of steels and alloys. The purpose of this work was to test the specialized "Metallography" module to determine the grain score of the image processing software "IMAGE – SP", as well as to check the reliability of the obtained results using the example of ferritic and austenitic steels.In the "Metallography" module, the analysis of standard images of annex No. 3 of Standart 5639-82, as well as real images of the structures of ferritic and austenitic steel, is carried out. It is shown that the results correspond to the definition of the Standart grain score. The divergence in the results is 1 point, which is acceptable.The active development of software products for the quantitative analysis of images in metallography will make it possible to legitimize the methods of computer measurement of parameters of the structures of metals and alloys by creating appropriate standards. Successful testing of the specialized "Metallography" module demonstrates opportunities and prospects for further development of specialized software products for measuring quantitative values of metal and alloy structures. The active development of software for quantitative analysis of the images in metallography will make it possible to legalize methods for measuring parameters of metal and alloy structures by computer techniques.
, N. V. Gusakovа, В. Э. Кисель, A. V. Kravtsov, S. A. Guretsky, A. A. Pavlyuk, N. V. Kuleshov
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-4-264-271

Abstract:
2 μm lasers are in demand for a number of practical applications, such as environmental monitoring, remote sensing, medicine, material processing, and are also used as a pump sources for optical parametric generators. Crystals of double potassium tungstates doped with ions of rare-earth elements were shown to be promising materials both for the creation of classical solid-state lasers and waveguide lasers. The aim of this work was to develop a tunable pump laser in the spectral region of 1.9 µm based on double tungstate crystals doped with thulium ions and to study the lasing characteristics of a Ho:KY(WO4)2 crystal and a Ho:KGdYbY(WO4)2 single-crystal epitaxial layer under in-band pumping.With a Ho(1at.%):KY(WO4)2 crystal, continuous wave low-threshold lasing with an output power of 85 mW with a slope efficiency of 54 % at 2074 nm was achieved. For the first time to our knowledge, continuous wave laser generation in a waveguide configuration is realized in a single-crystal layer of potassium tungstate doped with holmium ions grown by liquid-phase epitaxy. The maximum output power at a wavelength of 2055 nm was 16.5 mW.
A. V. Tertyshnikov
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-4-305-312

Abstract:
The miniature spacecraft have a high ballistic coefficient, which is advantageous for the resolution of sensing the density of the upper atmosphere. The purpose of this work is to show new features of the "falling spheres method" based on the miniaturization of the Spacecraft. The "falling spheres method" is used to probe variations in the density of the upper atmosphere.A technical solution for diagnostics of orbital sections with abnormal changes in the speed and acceleration of spacecraft equipped with onboard navigation receivers and micro-accelerometers is considered.The technical result of the proposed development is the efficiency and cost – effectiveness of sounding variations in the density of the upper atmosphere, seismic-orbital effects-variations in the density of the atmosphere over earthquake-regions and the seismic hazard.
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-3-245-254

Abstract:
The aim of the work was to study the contrasts of the images of an object observed in a smoky environment, using polarizing filtering of radiation scattered by smoke particles towards the observer, and without filtering. Prospects for developing optical accessories for firefighters to improve the observation of objects in smoke were evaluated by comparing image contrasts.The goal was achieved by experimentally simulating the process of transmitting images of a blackandwhite object with a sharp black/white transition boundary through various types of smoke aerosols using polarizing filtering of radiation scattered by smoke particles, and without filtering and evaluating image contrasts.Studies of image contrasts for different optical densities of smoke in two registration schemes were performed, when the receiving optical system is located near the illumination source of the object at a distance of ≈ 150 mm from it, and when it is located at a distance from the illumination source of the object at a distance of ≈ 800 mm.It is established that the method of forming the image of the object using polarization filtering of radiation backscattering (RBS) reduces the rate of image contrast reduction with an increase in optical smoke density compared to image registration without filtering (RBS).A significant difference in the contrasts of images recorded with filtration (RBS) and in the absence of it is observed for "light" fumes (smoldering of wood, cotton) at average optical densities of smoke.The results obtained can be used in the development of optical accessories for firefighter-rescuer to improve the conditions of observation of objects in adverse conditions of vision: smoke, vaporization, fog.
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-3-187-195

Abstract:
The paper presents a measuring stand designed and built for testing direct and alternating current properties of power transformers basic insulation component i.e. electrotechnical pressboard impregnated with transformer oil. Measurements of direct and alternating current parameters are performed using the frequency domain spectroscopy and polarization depolarization current methods.The measuring station includes a specially developed climatic chamber which is characterized by high accuracy of temperature stabilization and maintenance during several dozen hours of measurements. The uncertainty of temperature maintaining during several dozen hours of measurements does not exceed ± 0.01 °C. The computer software developed to control the station allows for remote measurements, changes in supply voltage and temperature settings and acquisition of the obtained results. A new type of measuring capacitor was developed and manufactured, the structure of which significantly reduces the chance of samples contamination during measurements. By increasing the accuracy of temperature stabilization during measurements, the resolution of measurement temperatures was increased, at which it is possible to perform measurements with the frequency domain spectroscopy and polarization depolarization current methods. This allowed to reduce the step of measurement temperature change and thus to increase the accuracy of determining the activation energy of the measured parameters.The article also contains basic information on the analysis of the direct and alternating current electrical parameters of the composite electrotechnical pressboard-mineral oil-water nanoparticles. The results of several direct and alternating current parameters measurements of a transformer oil impregnated pressboard sample with a moisture content of (5.2 ± 0.1) % by weight obtained by the use of a measuring stand are presented as examples.
, A. R. Li
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-3-228-235

Abstract:
The article notes the advantages of the method of constructing absolutely invariant measuring transducers for working in conditions with disturbing influences. However, this method is not universal. Its limitations are due to the impossibility of "symmetric" transmission of all disturbing influences into parallel measuring channels. A broader interpretation of the two-channel principle is proposed to overcome these limitations. The aim of the study was to substantiate and implement a method for constructing quasi-invariant measuring transducers and systems that retain their metrological characteristics under external disturbances of unknown physical nature.The theory that develops the two-channel principle to a full-fledged technological method is presented in the article. The theory includes the necessary and sufficient conditions for physical feasibility this method. Two fundamental tasks have been solved in the work. The first task is to identify signs that reflect the essence of the technological method in to specific cases and the second is to implement a methodology that allows these signs to be effectively applied in practice.In the examples, a complex of technologies is defined for groups of elements of quasi-invariant transducers that provide compensation of the influencing factors acting on them with acceptable accuracy.There are significant advantages in discussed method. It gives hope for acceptable measurement results under conditions when character and even physical principle of influencing a priori are unknown.
, В. Кисель, A. Yasukevich, K. Hovhannesyan, A. Petrosyan, N. Kuleshov
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-3-179-186

Abstract:
Yttrium aluminium perovskite YAlO3 (YAP) crystal, doped with rare-earth ions, has been extensively studied as a diode-pumped laser host material. The wide interest to rare-earth ions doped YAP crystals is explained by its good thermal and mechanical properties, high natural birefringence, widely used Czochralski growth method. The aim of this work was to study the Yb3+:YAlO3 crystal as an active medium for high power mode-locked laser.Yb3+-doped perovskite-like aluminate crystals have unique spectroscopic and thermooptical properties that allowed using these crystals as an active medium of high power continuous wave (CW) and modelocked (ML) bulk lasers with diode pumping.growth method. The aim of this work was to study the Yb3+:YAlO3 crystal as an active medium for high power mode-locked laser.In our work spectroscopic properties of Yb:YAP crystal and laser characteristics in CW and ML regimes are investigated. Maximum output power of 4 W with optical-to-optical efficiency of 16.3 % and 140 fs pulse duration have been obtained for Yb:YAP E //c-polarization with 10 % output coupler transmittance. Tunability range as wide as 67 nm confirms high promise of using Yb:YAP crystal for lasers working in wide spectral range.
T. Reader, V. A. Tenenev, A. A. Chernova
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-3-204-211

Abstract:
Assessment of the environmental and economic performance of a safety valve requires information about the flow of the substance through the valve when it is actuated. The goal of this paper was to determine the flow rate of the discharged substance and the mass flow rate of the substance entering the safety valve when it is actuated.Proposed a mathematical model to describe the processes occurring in the valve. The model includes a system of differential equations describing the physical laws of conservation in the internal volume of the valve and differential equations, which link the value of gas flow through the valve with the pressure and the amount of movement of the shut-off disk. Used a modified method by S.K. Godunov to solve gasdynamic equations.Established that the determination of the flow and power characteristics of the valve requires the preliminary construction of a mathematical model of the safety valve operation. Based on this, proposed a method for determining the flow rate of the discharged substance and the mass rate of the substance entering the safety valve when it is actuated.Obtained the flow characteristics of the valves under review and the dynamics of movement of the shutoff disc of the valve, as well as the dependence of the pressure change on the opening time of the valve. Comparison of the calculated values with available experimental data gives good agreement of results (no more than 5.6 % for a gas flow rate, under 10 % for the movement of the valve and change the arrival of gas in time using the standard deviation function of the flow characteristics of 0.6 %), confirms the correctness of the defined mathematical model, used numerical schemes and algorithms, as well as the proposed method and recoverability of the arrival of gas in a pressure–time curve.
I. A. Konovalov, A. E. Khrobostov, M. A. Legchanov, D. N. Solncev, A. A. Barinov, A. V. Ryazanov, A. A. Chesnokov, M. A. Makarov
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-3-196-203

Abstract:
The method of correlation measurement of the coolant flow rate, widely used for operational diagnostics of nuclear power plants, can be extensively used in research practice. The aim of this work was to apply a correlation method based on the conductometric measurement system with wire-mesh sensors for measuring a coolant flow rate.Insignificant concentration of a salt solution (NaCl or Na2SO4 ) creates a gradient of the conductivity in the flow, which is used as a passive scalar measured by the system. Authors used turbulent pulsations at the interface of two concurrent flows with identical velocities in a square channel as a signal source for the correlation method. The paper presents the methodology of the tests, test facility description, signalto-noise ratio estimation, the results of digital signal processing and comparison of the measured velocities in the model with the flowrate‒averaged velocity determined by the use of flowmeters. The measured velocity values give acceptable agreement for the turbulent flow modes. It was shown that the measurement accuracy drops sharply for low-Reynolds flows.The obtained results were used for flowrate measurements in core-imitator channels of the nuclear reactor test model. The presented paper is an approbation of this approach for its application as part of an test model of a nuclear reactor in order to determine the each duct flow rates in the channels of the core simulator using wire mesh sensors.
D. P. Ilyaschenko, A. V. Kryukov, E. V. Lavrova, M. A. Kuznetsov, E. V. Verkhoturova
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-3-222-227

Abstract:
The nature of the molten electrode metal melting and transfer is the main process parameter of manual metal arc welding (MMA) with coated electrodes. It significantly affects the efficiency of the welding process. For this reason the relevant task is to identify the parameters of the transferred molten electrode metal drops and their further transfer into the weld pool with maximum accuracy. The aim of the given paper is to develop a method and visual representation of the form and the geometrics (volume, area, mass) of a molten electrode metal drop.We have developed the method of simulation modeling and visualization for molten electrode metal drops transfer and their parameters. It allows obtaining highly reliable input data to be used for developing and verification of mathematical models for the thermal fields distribution along the welded item surface. The algorithm is realized as the calculation programs for specifying the molten metal drop parameters and means of its geometrics and space form visualization.We used this method to specify a number of molten electrode metal drop parameters: volume, mass, center-of-gravity position, surface area.We have established that it is possible to conduct the measurements with maximumThe suggested method significantly decreases the labor intensity of experimental studies aimed at specifying the size of electrode metal drops in comparison to the standard methods. When we know the size of the drops under certain welding conditions we can control the drop transfer process, i. e. reduce the heat input into the welded item and produce weld joints with the tailored performance characteristics.
A. A. Skazochkin, G. G. Bondarenko, P. Żukowski
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-3-212-221

Abstract:
One of the important characteristics of the surface properties of metal parts subjected to friction is hardness. Hardness measurements are important for determining the operational characteristics of parts and monitoring the technological regimes of surface modification. However, hardness measurements of thin modified layers made by different methods can lead to differences in measurement results. The aim of the article was to study the hardness of a metal surface modified with ultrafine particles of minerals by two different methods (instrumental indentation and Vickers hardness measurement) and a comparative analysis of the measurement results obtained by these methods.Standard Vickers hardness measurements at loads of 0.025, 0.1 and 0.5 kgf showed a qualitative difference between the hardness values of the two samples modified with different mixtures of ultrafine particles of minerals and a large heterogeneity of the hardness values over the area. By the method of instrumental hardness, standard measurements were performed without preliminary selection of the indentation site (at a load of 1.05 N) and measurements during indentation into even sections (at low loads of 10 mN).It is noted that the high precision of measurements implemented by instrumental indentation, due to the large roughness of the samples, leads to large values of the error in calculating the measurement results. An additional difference in the results of measurements performed by two methods at shallow indentation depths may be due to the fact that the object under study has a complex structure consisting of a metal matrix and particles distributed over the depth of the sample. A possible way out of the situation lies in the transition from the use of hardness measures when calibrating instruments to standard samples of properties for which the constancy of mechanical properties in the measured range of indentation depths will be ensured, but which are not yet available in research practice. Therefore, at present, when carrying out work related to the search for optimal conditions for obtaining thin wear-resistant layers on the surface of metals modified with ultrafine particles of minerals, comparative measurements performed by one measurement method are recommended.
С. Г. Сандомирский
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-3-236-244

Abstract:
All measurements of mechanical properties of materials in the magnetic structural analysis are indirect and relationships between the measured parameters are correlated. An important physical parameter of steel is hardness. An increase in the correlation coefficient R and a reduction in the standard deviation (SD) are achieved when controlling the hardness of steels with two-parameter magnetic methods compared to methods that use a single measured parameter. However, the specific conditions and requirements for application of the two-parameter methods remain unclear. The purpose of this article was to analyze conditions and the achievable error reduction limit for two-parameter indirect determination of steels hardness and to compare those with one-parameter methods.In particular, we considered the mean Square Deviation (SD), σF , of indirect calculation of the physical quantity F using two measured parameters x1 and x2 that are correlated with F. It was found that reduction of σF is most pronounced when x1 and x2 are inversely correlated with the maximum modulus |R| of the correlation coefficient R between them. The most significant reduction in σF occurs at similar values of the SDs σ1 and σ2 between the true value of F and the values calculated based on the results of indirect measurements of F usingeach of the parameters x1 and x2 . The Results of the analysis are confirmed by an example of reduction in SD when determining the hardness of carbon steels by measuring their remanent magnetization and coercive force compared to use any one of these parameters.This result can be applied to measurements in non-destructive testing and in related fields of physics and technology. The Results of the analysis allow us to compare different parameters for indirect two-parameter determination of a physical quantity, to select the optimal parameters, and to evaluate the minimum achievable measurement error of a physical quantity by a two-parameter method before performing the measurements.
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-3-171-178

Abstract:
The study uses the phenomenon of high voltage partial discharge to investigate the phenomenon of percolation and visualisation of the percolation channel. The phenomenon of partial discharges is very similar to the quantum tunneling phenomenon observed in metal-dielectric nanocomposites. In both cases the flow of alternating current occurs in the absence of direct contact between the metallic phase particles.A measuring stand was developed and constructed to test models of metal dielectric nanocomposites using high voltage partial discharge. The stand consists of a 110 kV high voltage transformer, a voltage regulator protecting the constant rate of high voltage rise, a measuring system consisting of a measuring probe, voltmeters and a computer. The communication between the measuring probe and the voltmeter was made in digital technology with the use of fiber optic technology, which allowed the meter to communicate with the computer without any errors and eliminated the interference caused by a strong electromagnetic field resulting from the use of high voltage.Systems modelling metal-dielectric composites were built, consisting of metallic elements in the form of disks, randomly distributed on the surface of the dielectric matrix. The number of disks was increased in series of 40 in each. The maximum number of disks was 1520. The dependence was determined of one of the important parameters characterising an partial discharge, i. e. the initial voltage, at which an electric current starts to flow between electrodes, on the concentration of the metallic phase. On the basis of these results, a percolation threshold was established for a matrix with a random distribution of metallic phase elements, the value of which is about 50 %. Films and pictures of partial discharges with visible percolation channels were taken with the camera with which the stand was equipped.
, I. A. Safina
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-2-155-162

Abstract:
The spectral method for establishing dynamic response of measuring instruments basically requires determining the amplitude spectrum of the signal in its informative part that includes the amplitude spectrum at zero frequency. The operating frequency range of existing low-frequency spectrum analyzers is above zero frequency that leads to an uncertainty in dynamic response of measuring instruments determined by the spectral method. The purpose of this paper is to develop a program for calculating the signal amplitude spectrum, starting from zero frequency, to implement a spectral method for determining the dynamic response of measuring instruments on computers equipped with the MatLab package.To implement the spectral method for determining the dynamic response of measuring instruments, we developed a program in the MatLab 2013b environment that determines the signal amplitude spectrum from zero Hertz. The program reads the source data from Excel tables and presents the calculated amplitude spectrum as a chart and a report table.It is shown that the developed program calculates the signal amplitude spectrum with a standard deviation of not more than 3.4 % in the frequency range of 0 to 10 rad/s. The calculated amplitude spectrum allows determining the time constant of first-order aperiodic measuring instruments with an uncertainty of not more than 0.166 % at any noise level, if their frequencies are outside the information part of the spectrum.We demonstrated the claimed advantage of the spectral method for determining dynamic response using the developed program by the example of a high-frequency noise in the transient response of some measuring instruments.
V. A. Alekseev, , V. P. Usoltsev, D. N. Shulmin
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-2-114-121

Abstract:
As a rule, the wastewater treatment system is not designed to filter substances formed, as a result of beyond design basis accident. The nature of the beyond design basis accident is associated with the shortterm appearance of a clot of these substances in wastewater, determined by the volume of the substance storage tank. Therefore, a rational approach is to divert this portion of the formed substances into a separate branch of the sewage system or sedimentation tanks. The aim of the work is to implement this approach by creating a laser monitoring system for water pollution.The article proposes a system for automatic detection of a clot of emergency discharge of pollutants into the wastewater of an industrial enterprise. The structural diagram of the system and the purpose of its main elements are given. The system should provide clot detection in real time. To ensure this function, a preliminary study is made of the spectral characteristics of all substances that may appear in wastewater in the event of an emergency.Based on these data, the wavelengths of laser radiation in the system are selected. The obtained measurement data from several probes are presented in the form of a lattice function, which is translated into a relative description representing the order relationship matrix on the set of lattice function components. The relative description is invariant to linear changes in the lattice function. The decision to detect any substance from emergency discharges is made based on a comparison of the relative description of the measurements with the standards prepared at the stage of system setup.The article provides an example of the formation of standards for emergency clots from glycerin and allyl alcohol. The graphs of the lattice functions obtained from the IR spectra of emergency discharges of these substances are given; algorithms for constructing a lattice function and comparison of lattice functions. Thus, using the developed mathematical description of the shape of digital signals based on the relative description, the signal of the monitoring curve can be described in the form of a curve of the optical density change of an aqueous medium.
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-2-132-139

Abstract:
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.
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-2-122-131

Abstract:
A digital micromirror device (DMD) micromirrors periodic spatial structure is a measuring scale in interior orientation parameters calibration of optoelectronic devices problems, when using a DMD as a testobject. It is important that DMD micromirrors periodic spatial structure remains constant. Change in a DMD micromirrors spatial structure may occur due to heating. In addition to heating a DMD, an optoelectronic device photodetector is also subject to heating and, accordingly, change in its spatial structure. It is necessary to estimate change in a spatial structure of DMD micromirrors and an optoelectronic device photodetector.A DMD micromirrors spatial drift and a DMD micromirrors spatial drift together with a digital camera photodetector pixels spatial drift for operation 4 h are analyzed. The drift analysis consisted in the points array position assessing formed by a DMD and projected onto a digital camera. When analyzing only a DMD micromirrors drift, a digital camera was turned on only for shooting time for exclude digital camera influence. A digital camera did not have time to significantly heat up, during this time. After a digital camera it cooled to a room temperature.Average drift of all DMD micromirrors determines the accuracy of interior orientation parameters calibration of optoelectronic devices using a DMD in time. Maximum drift of all micromirrors after switching on is observed. Minimum DMD warm-up time is 60 min for average drift of all micromirrors less than 1 μm is necessary. Minimum DMD warm-up time is 120 min when using a DMD together with a digital camera is necessary.A DMD expansion uniformity determines the accuracy of interior orientation parameters calibration of optoelectronic devices using a DMD, because irregular expansion disturbs micromirrors periodicity. The average change in distance of neighboring points is less than 0.1 μm for every 20 min.Thus, a DMD can be used as a test-object in interior orientation parameters calibration of optoelectronic devices. The results can be used as compensation coefficients of change in DMD micromirrors spatial structure due to temperature effects during operation, if more accurate are necessary.
Volodymyr Halchenko, ,
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-2-91-104

Abstract:
Development of technical tools with improved metrological and operational characteristics is the actual problem of the eddy current testing. Ensuring the optimal distribution of the electromagnetic excitation field in the testing zone carries out confident detection of the defects and determination of their geometrical parameters by means of eddy current testing. The purpose of the work was to conduct an analysis of scientific and technical information in the field of eddy current testing to study of the use of electromagnetic excitation fields with a priori specified properties, as well as to generalize and systematize the accumulated experience and approaches to conduct theoretical research in this direction.A review of publications in the field of non-destructive electromagnetic testing devoted to the improvement of the excitation systems of eddy current flaw probes was carried out. The authors considered approaches in which a uniform distribution of the electromagnetic field on the control object surface was achieved by linear and non-linear optimal synthesis of excitation systems, provided the immobility of the probe relative to the testing object. Analysis of eddy current probe designs with a homogeneous excitation field created by circular, rectangular tangential and normal coils, as well as by creating a rotational excitation field was carried out. The authors studied designs of the excitation coils of probes with fields of complex configuration characterized by the original fractal geometry which can increase the probability of identifying defects that were not amenable to detection by classical probes.Studies that suggested the formation of optimal configuration fields in a given area using magnetic cores, field concentrators made of conductive materials and specially shaped screens were analyzed. The authors studied approaches to the implementation of the optimal synthesis of excitation systems of probes with uniform sensitivity in the testing zone using surrogate optimization for cases of moving testing objects taking into account the speed effect.The experience, as well as the results of theoretical studies devoted to the problem of designing eddy current probes with uniform sensitivity in the testing zone due to the uniform density distribution of the induced currents flowing in the object were generalized and systematized. As a result, the classification of probes on a number of features that characterize the excitation systems was proposed.
, S. I. Rudikov, A. P. Shumski, A. P. Shkadarevich
Devices and Methods of Measurements, Volume 11, pp 115-113; https://doi.org/10.21122/2220-9506-2020-11-2-105-113

Abstract:
The development of non-lethal weapons and, in particular, temporary blinding devices is associated with problem of choosing boundaries of effectiveness. The aim of present work is determination of criteria for estimation of the effects of visual jamming devices action on the naked eye.The present-day scoring system used for effectiveness estimation of laser temporary blinding devices is based on maximum permissible exposure and/or accessible emission level defined for each hazard class in accordance with operating standard.In the present work we carried out analysis and modeling of the cases of application of temporary blinding laser devices. The proposed scoring system was founded on international standard IEC 60825-1-2014 as well as Manual on Laser Emitters and Flight Safety. The modeling of bright light action on observer eye was rested on CIE General Disability Glare Equation and provided quantitative description of jamming effectiveness. The main parameters used in this model and dictated by ambient light level and human eye characteristics, were veiling luminance and angle of distinguishing objects under it.In terms of exposition level and perception effects we determined six zones – unallowed, hazard, temporary blinding, discomfort, alerting, completely safe. Proposed system combined with modeling provides with visual demonstration of perceived light source and allows to describe human physiological sensation and to establish the fact of jamming at different distances. This system was the basis of the development of temporary blinding device for revelation of safe but effective spatial boundaries of action.
E. G. Zaitseva, M. V. Chernetsky, N. A. Shevel
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-2-148-154

Abstract:
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.
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-2-140-147

Abstract:
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.
A. M. Timofeev
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-1-70-81

Abstract:
Приёмные модули однофотонных систем связи при измерении маломощных оптических сигналов должны обеспечивать наименьшие потери передаваемой информации. В этой связи целесообразно использовать счётчики фотонов, которые являются высокочувствительными, однако характеризуются ошибками регистрации данных. Цель работы – разработать методику определения интенсивности регистрируемого оптического излучения в канале однофотонной связи с приёмным модулем на основе счётчика фотонов, позволяющую уменьшить вероятность ошибочной регистрации передаваемых двоичных символов.Разработаны методика снижения потерь информации в асинхронном двоичном однофотонном канале связи с приёмником на основе счётчика фотонов и устройство, её реализующее. Данная методика основана на использовании статистических распределений смеси числа темновых и сигнальных импульсов, полученных на выходе счётчика фотонов при регистрации двоичных символов «0» Pst 0 (N) и «1» Pst 1 (N). Сущность методики...
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-1-53-59

Abstract:
Рассмотрены конструктивные параметры и свойства чувствительных материалов, влияющие на время отклика ёмкостных датчиков влажности на основе полимеров. Выполнен краткий обзор и анализ способов определения динамических характеристик ёмкостных датчиков влажности в технической документации ведущих производителей, представленных на рынке.Приведено описание схемы и работы экспериментальной установки для определения динамических характеристик ёмкостных датчиков влажности при различных значениях температуры влажного воздуха. Динамические характеристики ёмкостных датчиков влажности на основе полимеров определялись в виде отклика выходного сигнала при ступенчатом изменении влажности как с положительным, так и с отрицательным шагом. Времена отклика и восстановления, а также постоянные времени для экспоненциальной аппроксимации отклика на ступенчатое воздействие, определялись на основе результатов измерений графически либо аналитически.Проанализированы...
, V. L. Hurevich, Т. К. Тоlochko
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-1-69-69

Abstract:
Рассмотрены особенности эффективного применения комбинированного подхода к оцениванию неопределённости результатов измерений. Целью данной работы являлось обоснование и развитие новых наукоёмких подходов по достижению максимальной эффективности измерений по критерию «точность/трудоёмкость» при заданной степени доверия.Теоретически обоснована корректность комбинированного подхода к оцениванию неопределённости результатов измерений. Предложено процесс измерения условно делить на фрагменты – объекты комбинирования, каждый из которых следует рассматривать как самостоятельный элемент оценивания. Установлено, что объекты комбинирования могут быть сформированы путём группирования либо отдельных компонентов (ресурсов) процесса измерений, либо отдельных этапов процесса измерений.Корректность такого подхода обоснована применением «ресурсного» и «процессного» подходов к идентификации влияющих на неопределённость результата измерений. Приведены...
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-1-42-52

Abstract:
Компьютерное моделирование находит широкое применение в разработке и оптимизации мощных источников отрицательных ионов для будущих термоядерных реакторов, в частности, ITER. Целью настоящей работы являлось изучение изменений качества генерируемого пучка (характеризуемого параметрами эмиттанса и яркости) в зависимости от геометрии вытяжной системы и выходного напряжения.Для моделирования извлечения ионов Hи электронов из плазменной камеры источника ионов через канал со скошенной поверхностью использовался двумерный метод частиц в ячейке (PIC). Среднеквадратическое значение эмиттанса извлечённого пучка рассчитывалось на основе подхода Часмана и Лапостолле. Дополнительно приводятся ионно-лучевые фазовые пространственные изображения ионного пучка.Рост эмиттанса ионного (электронного) пучка наблюдался при увеличении как радиуса вытяжного канала, так и наклона его скошенной поверхности. Данное ухудшение качества пучка частично компенсируется увеличением ионным...
A. S. Levytskyi, , V. O. Bereznychenko, O. E. Sukhorukova
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-1-33-41

Abstract:
Одним из важнейших параметров мощных гидрогенераторов является воздушный зазор между ротором и статором, и его отклонение от заданных норм является дефектом, который может привести к серьёзным авариям. Поэтому величину и форму зазора необходимо контролировать как во время осмотров, так и при эксплуатации машины. Целью данной работы являлась разработка вторичного измерительного преобразователя, обеспечивающего точность и разрешающую способность, для ёмкостного сенсора зазора, образованного компланарными параллельными электродами.Рассматриваются особенности измерения воздушного зазора в мощных гидрогенераторах, а также существующие современные методы и средства измерений. Показано, что для измерения зазора в гидрогенераторах одним из наиболее подходящих средств является измеритель, в состав которого входит ёмкостный сенсор, устанавливаемый на расточке сердечника статора. Серийно выпускаемые измерители зазора с ёмкостными сенсорами по своим некоторым...
, В. Э. Кисель, A. S. Yasukevich, K. L. Hovhannesyan, A. G. Petrosyan, N. V. Kuleshov
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-1-7-14

Abstract:
Компактные регенеративные усилители чирпированных импульсов с диодной накачкой, обеспечивающие частоту повторения усиленных импульсов в сотни килогерц, построенные на материалах, легированных ионами Yb3+, представляют практический интерес для широкого ряда научных, промышленных и биомедицинских применений. Целью данной работы являлось исследование регенеративного усилителя на кристалле Yb3+:LuAlO3 с усилением отдельных спектральных компонент импульсов задающего лазера.Кристаллы алюминатов со структурой перовскита обладают уникальными спектроскопическими свойствами, что позволяет использовать спектр усиления активной среды регенеративного усилителя в качестве амплитудного фильтра и усиливать отдельные участки спектра импульсов задающего лазера без каких-либо дополнительных оптических компонентов.В данной работе впервые исследован простой подход, позволяющий использовать спектр усиления активной среды регенеративного усилителя как амплитудный фильтр для...
, Y. A. Zavatski, A. V. Kovalenko, A. M. Naumenko
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-1-22-32

Abstract:
For the effective use of dielectric sensors, optimization of the design parameters of the sensors, such as the depth of penetration of the electromagnetic fi and the magnitude of the sensor signal, is of great importance. The purpose of the work was to build a mathematical model of a sensor with an open area of space and calculate its parameters.Results of main parameters calculations of the open space sensor are presented. Methods of integral equations and mirror images are used for numerical 2D modeling. The surface of each electrode was considered as two parallel lamellae. This approach simplifi the procedure for numerically solving a two-dimensional problem. It allows you to calculate the electric fi of fl layered media with less time, using less powerful computers. The numerical calculation program is implemented in MAPLE.The program adequacy was checked for a sensor made on one-sided foil Tefl (ε1 = 2,3) with a thickness of b = 1.0 mm. The electric fi was calculated for the sensor in a three-layer medium. The calculated picture of the fi showed that the distribution of force lines is not uniform. It was found that the depth of the control zone does not depend on the metallization of the sensor surface. The depth of the control zone for an open-type sensor is in the same range as the depth of the control zone for fl overhead measuring capacitorsan analog of fringing electric fi d (FEF) sensors.
N. K. Artioukhina, L. Peroza
Devices and Methods of Measurements, Volume 11; https://doi.org/10.21122/2220-9506-2020-11-1-15-21

Abstract:
В настоящие время проблема поиска и проектирования новых схемных решений зеркальных систем, включая афокальные, остается актуальной. Широкое применение зеркальных систем в астрономии, спектральных приборах, лазерном оборудовании и других приложениях обусловлено некоторыми их достоинствами: высоким разрешением в широком спектральном диапазоне, отсутствием дефектов изображения, возникающих из-за хроматических аберраций и ограничений по апертуре, связанных с размерами заготовок, выигрыш по весу. Целью данной работы являлось создание компактных афокальных зеркальных систем с малыми осевыми габаритами.Представлены схемы конструкций афокальных зеркальных систем из трех параболических зеркал с малыми осевыми габаритами. Проведено исследование афокальных систем, в которых относительное отверстие первичного зеркала, определяющее диаметр апертурной диафрагмы, оптимизировано с целью создания более компактной системы.Предложен алгоритм параметрического расчета...
M. Gutten, M. Šebok, D. Korenčiak, P. Brnčal, M. Kubiš, P. Żukowski,
Devices and Methods of Measurements, Volume 10; https://doi.org/10.21122/2220-9506-2019-10-4-353-359

Abstract:
The first part of paper deals with the base information about diagnostics of power transformers. In this part are presented differently insulating methods, for example method of recovery voltage method, method of polarization and depolarization currents and chromatographic analysis.The second part of paper deals use of method of frequency domain spectroscopy for oil power transformers. This method is used in analysis insulating condition of power transformer with system of oil-paper. It was found, that the results of these tests are highly impacted by the operating temperature during the experimental measurement. Moisture and conductivity between insulating paper and oil in an insulating system are highly dependent from temperature.In the other part, the paper presents experimental results of the frequency diagnostic measurement for a real single-phase traction transformer 110/27 kV at different operating temperatures and states (with oil and without).Finally in the last part, the paper presents comparing frequency insulating measurements among several the same single-phase transformers 110/27 kV.
, N. V. Levkovich, A. L. Mayorov, M. V. Asadchaya
Devices and Methods of Measurements, Volume 10; https://doi.org/10.21122/2220-9506-2019-10-4-360-372

Abstract:
Improving the reliability and testing performance of permanent joints оf different materials made by welding, spraying, gluing, soldering and other methods is an important production task, for which the ultrasonic method is the simplest and most effective. The purpose of this work was to expand the technical possibilities and increase the sensitivity of ultrasonic testing of adhesion defects of materials joints based on the establishment of laws governing the formation of a scattering field of elastic waves from an inhomogeneous boundary in three-dimensional space and issuing recommendations for the development of suggested method.For the first time, in the framework of classical concepts, the scattering fields of elastic waves of an acoustic beam with a circular cross section moving across the boundary of a semi-infinite defect are calculated. It is proposed to use a phase shift between the waves reflected from the indicated surfaces, which varies in the range of π/4–π, as an important parameter of the material joint's defect. It has a significant effect on the field pattern and its angular amplitude extrema — minima and maxima of different orders when the defect boundary is moved relative to the center of the acoustic beam spot.The features of the evolution of the structure of the scattering field are established, which make it possible to identify optimal conditions for the detection of weakly reflective defects in sound. It is shown that it is possible in principle to estimate the defect's area by measuring a change in the amplitude of the primary maximum of the radiation pattern of the scattered waves.Specific examples show the effectiveness of using the proposed method for a number of practical applications.
A. A. Spiridonov, D. V. Ushakov, V. A. Saechnikov
Devices and Methods of Measurements, Volume 10; https://doi.org/10.21122/2220-9506-2019-10-4-331-340

Abstract:
Currently, ultra-small satellite aresubjectstostringentrequirementsintermsoftheaccuracyof determining the position of the satellite in orbit, while the satellite is the subject to restrictions on mass, size and power consumption. The aim of this work is to simulate of navigation receiver operation for the ultra-small satellite with restrictions on energy consumption and computational resources.The operating conditions are considered and the requirements to the onboard navigation receiver for the ultra-small satellite are determined. The navigation receiver operation at the initial stage, performance testing, error detection, analysis of the reliability of the solution of the navigation-time determination problem are described.The structure of the design ballistics problems for orbit prediction of ultra-small spacecraft and navigation satellites, radio visibility intervals for GLONASS and GPS systems, parameters of navigation signals have been developed.The motion relative to the satellite systems GPS and GLONASS for a preliminary orbit of СubeBel-1 have been simulated. The Doppler dynamics of the GPS satellite signals in the receiver without restrictions on the relative speed for one day has been calculated. Radio visibility intervals for GPS and GLONASS satellites were calculated and optimal conditions for the cold start of the navigation receiver with a relative speed limit (Vr < 500 m/s) for 1 hour of operation both in separate and in joint operation on both systems were determined.To test the verification methods of the experimental data of the СubeBel-1 satellite, the operation of the navigation receiver of the Nsight satellite was studied according to the received telemetry from the beginning of its flight until the moment it entered stable operation.It is shown that the telemetry data of the navigation receiver at the testing stage had a significant error. After software correction, the navigation receiver worked steadily throughout the week of observation, the error of longitude and latitude measurements did not exceed 0.2 degrees.
I. Z. Gilavdary, S. Mekid,
Devices and Methods of Measurements, Volume 10; https://doi.org/10.21122/2220-9506-2019-10-4-308-321

Abstract:
Currently, the study of rolling friction is one of the main directions in the study of the laws of contact interaction of solids. The complexity of solving the problems existing in this area is evidenced by the practically vast number of publications, the list of which is constantly growing.In this paper, attention is paid to studies of the moments of rolling resistance at displacements from the equilibrium position of a ball-shaped body that are substantially smaller than the size of the contact spot. The purpose of the present work is to describe the design of the single-contact pendulum device developed by the authors, in which the physical pendulum, resting on the flat surface of the body under study with only one ball, makes free small stable swings in a vertical plane, as well as in the description of a special measurement technique with high sensitivity and accuracy rolling resistance forces, including adhesion forces and frequency-independent forces of elastic deformations. It is assumed that the adhesion forces can exhibit both dissipative properties and elastic properties, while elastic forces are independent of the strain rate.The originality of the method of measuring rolling resistance in this paper consists in using the method of nonlinear approximation of the dependence of the amplitude and period of swing of the pendulum on time. The approximation is carried out on the basis of the proposed laws of amplitude decay and period variation, which differ from the usual exponential law.It is assumed that this approach allows one to evaluate the surface tension of a solid and evaluate the pressure of adhesion forces between the surfaces of the contacting bodies, as well as to establish an analytical form of the moment of rolling resistance. The curves of the dependence of the rolling resistance moment on the swing amplitude of the pendulum are constructed. Experiments were performed for the following pairs of contacting bodies: steel-steel, steel-glass, steel-electritechnical silicon. It was assumed that the pressure at the contact spot did not exceed the elastic limit.The developed single-ball pendulum device and the proposed measurement procedure open up new wide possibilities for studying the laws of mechanisms of rolling resistance under conditions of microand mesoscale displacements of a rolling body from a state of rest.
R. V. Fiodоrtsev, A. R. Silie Cuenca, D. A. Kozhevnikov, Виктор Мануэль Медина, R. Delgado
Devices and Methods of Measurements, Volume 10; https://doi.org/10.21122/2220-9506-2019-10-4-373-381

Abstract:
The object of the study is software methods of the Earth surface images processing obtained from the VRSS-2 satellite to determine the spectral composition of the vegetation cover to detect the presence of carotenoids during prolonged exposure to hydrocarbons.The photosynthetic pigments of higher plants (chlorophylls, carotenoids and phytobiliproteins) were analyzed. In the chloroplasts of higher plants, chlorophyll and carotenoids are present in a ratio of about 3:1. The presence of hydrocarbons increases the amount of carotenoids. Carotenoids have absorption bands in the blue-violet region from 400 to 500 nm and a high reflection coefficient in the red-orange and yellow spectral regions, which corresponds to the multispectral MSS operating mode (B2) of the VRSS-2 satellite camera. An analysis of the vegetation growing in the study area of the Puerto Kumarebo settlement showed that the best indicator of the presence of hydrocarbons in the soil is Prosopis juliflora – CUJI with a deep root system of up to 50 m, growing in the study area.Using ENVI software, a comparative evaluation of the efficiency of photographs image processing was carried out using the normalized relative vegetation index (NDVI) and the structure-insensitive pigment index (SIPI) to detect changes in the color of green vegetation. It has been established that the SIPI index is more applicable for hydrocarbon search tasks. Moreover, the recorded index fluctuations in the area of uniform vegetation at the level of 2.5 % are characteristic of normal growing conditions and cannot serve as evidence of the presence of factors indicating the presence of hydrocarbons in the soil. For a more detailed assessment of the presence of carotenoids in the foliage and the presence of hydrocarbons in the soil, photographs with high optical resolution of objects on the surface are required.
Devices and Methods of Measurements, Volume 10; https://doi.org/10.21122/2220-9506-2019-10-4-391-401

Abstract:
The aim of the paper was to develop a model of thermal extinguishing mechanism using dry chemical powder taking into account the inertia of heat transfer to powder particles during unsteady heat exchange to identify the optimal conditions for extinguishing of A1 class fires with powders.The method of experimental and mathematical modelling of fire extinguishing process using dry chemical powder with short-term effect on the fire was used to achieve the goal. The experimental dependences of the extinguishing time and unit consumption of the extinguishing powder on the intensity of the powder supply to the combustion zone in extinguishing of subclass A1 fire in same area and in a limited volume were obtained. The mathematical model of a thermal extinguishing mechanism using dry chemical powder has been developed, taking into account the inertia of heat transfer to powder particles during unsteady heat exchange.Analysis of the regularities of extinguishing the subclass A1 fire using powder with a short feeding it into the fire indicates the presence of optimum values of unity consumption of powder on the fire from the intensity of feeding it into the fire. The presence of this optimum is due to the inertia of extinguishing the subclass A1 fire using powder due to the finiteness of the heat transfer time to the particles of the extinguishing powder and the limited time of interaction of particles with the combustible material.The theoretical analysis of the fire extinguishing process over the area taking into account the inertia of heat transfer to the powder particles at non-stationary heat exchange are carried out. The results of the analysis are in qualitative agreement with the results of the experimental study of the regularities of extinguishing of model fire foci of subclass A1 with General-purpose fire extinguishing powder.
K. N. Gorbachenya, В. Э. Кисель, R. V. Deineka, A. S. Yasukevich, N. V. Kuleshov, V. V. Maltsev, D. D. Mitina, E. A. Volkova, N. I. Leonyuk
Devices and Methods of Measurements, Volume 10; https://doi.org/10.21122/2220-9506-2019-10-4-301-307

Abstract:
We report, for the first time to our knowledge, a diode-pumped continuous-wave microchip Er,Yb:YMgB5O10 laser. The purpose of this work was to study the growth technique, spectroscopic properties and continuous-wave laser performance of Er3+,Yb3+:YMgB5O10 novel crystal. Absorption and luminescence spectra as well as kinetics of luminescence decay were studied. Ytterbium-erbium energy transfer efficiency was determined. The output characteristics (output power, slope efficiency, laser wavelength) of Er3+,Yb3+:YMgB5O10 laser were determined.Two intensive absorption bands with peaks centered at 937 nm and 976 nm were observed in the absorption spectra at the wavelength near 1 μm. The maximum value of absorption cross-section was determined to be 1.5·10–20 cm2 at 976 nm for polarization E//Ng . A number of narrow lines were observed in the absorption spectra in the 1425–1575 nm spectral range (transition 4I15/2 → 4I13/2 of erbium ions). The lifetime of the upper laser level 4I13/2 of Er3+ ions was determined to be 390 ± 20 μs. The ytterbium-erbium energy transfer efficiency for YMgB5O10 crystal with 2 at.% of Er3+ and 11 at.% for Yb3+ was close to 84 %. The maximal continuous-wave output power of 0.2 W with slope efficiency of 8 % regarding to absorbed pump power was realized at the wavelength of 1570 nm. With the improvement of cavity parameters the output laser performance of the Er,Yb:YMgB5O10 crystal can be further enhanced.Taking into account high thermal conductivity of ≈ 6.2 W·m–1·K–1, the Er,Yb:YMgB5O10 crystal can be considered as a good gain medium for 1.5 μm lasers for applications in laser rangefinder and LIDAR systems.
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