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Introduction. The processes of structure formation of cement compositions and the development of effective technologies of building materials is an urgent task for building material science. The use of large-scale man-made product of pulp and paper enterprises – osprey as a fibrous filler in organic and mineral compositions is the successful decision of the problem. The paper analyzes the ways of using osprey in the building materials’ production. The aim of the research is to study the osprey influence on the processes of structure formation of cement stone by quantitative x-ray phase analysis.Materials and methods. The organic and mineral compositions were obtained on the basis of portland cement and osprey. The authors studied the compositions’ phase of osprey, portland cement and the processes of cement stone structure formation in organ and mineral compositions by quantitative x-ray phase analysis.Results. The authors determined the compositions’ phase of mineral impurities of osprey, cellulose, cement, cement stone, organic and mineral compositions and two compositions containing 25 and 75% by weight.Discussion and conclusions. The osprey application as a filler in the organic and mineral composition causes inhibition of processes of cement hydration. The presence of osprey in the hardening organic and mineral composition leads to a change in the composition and structure of the cement stone in comparison with the phase composition of the cement stone without additives. The result of these changes is a significant increase in the amount of calcite, waterite and a significant decrease in the amount of portland. The authors establish that the effective joint work of the reinforcing component of the osprey with the cement matrix is possible with a limited amount of osprey in organic and mineral compositions.

Objectives. Since the end of the 20th century, liquid crystals have taken a leading position as a working material for the display industry. In particular, this is due to the advances in the control of surface orientation in thin layers of liquid crystals, which is necessary for setting the initial orientation of the layer structure in the absence of an electric field. The operation of most liquid crystal displays is based on electro-optical effects, arising from the changes in the initial orientation of the layers when the electric field is turned on, and the relaxation of the orientation structure under the action of surfaces after the electric field is turned off. In this regard, the high quality of surface orientation directly affects the technical characteristics of liquid crystal displays. The traditional technology of rubbing substrates, currently used in the display industry, has several disadvantages associated with the formation of a static charge on the substrates and surface contamination with microparticles. This review discusses an alternative photoalignment technology for liquid crystals on the surface, using materials sensitive to polarization of electromagnetic irradiation. Also, this review describes various applications of photosensitive azo dyes as photo-oriented materials. Results. The alternative photoalignment technology, which employs materials sensitive to electromagnetic polarization, allows to create the orientation of liquid crystals on the surface without mechanical impact and to control the surface anchoring force of a liquid crystal. This provides the benefits of using the photoalignment technology in the display industry and photonics—where the use of the rubbing technology is extremely difficult. The optical image rewriting mechanism is discussed, using electronic paper with photo-inert and photoaligned surfaces as an example. Further, different ways of using the photoalignment technology in liquid crystal photonics devices that control light beams are described. In particular, we consider switches, controllers and polarization rotators, optical attenuators, switchable diffraction gratings, polarization image analyzers, liquid crystal lenses, and ferroelectric liquid crystal displays with increased operation speed. Conclusions. The liquid crystal photoalignment and photopatterning technology is a promising tool for new display and photonics applications. It can be used for light polarization rotation; voltage controllable diffraction; fast switching of the liquid crystal refractive index; alignment of liquid crystals in super-thin photonic holes, curved and 3D surfaces; and many more applications.

В работе представлены результаты исследования структуры и свойств бумажных обеззоленных фильтров «Синяя лента». Показано, что фильтровальная бумага «Синяя лента» имеет достаточно высокую плотность с относительно малым количеством и размеров пустот (пор) между волокнами. При обработке фильтров в поле коронного разряда наблюдается повышение их механических свойств на 3.5–6%, что вызвано преимущественно усилением межволоконных сил связей. Реализация повышенных электростатических сил связей в структуре листа приводит к увеличению сопротивления внешней растягивающей силе, необходимой для разрыва бумажного фильтра. Наблюдаемые зависимости связаны с ориентацией и упорядочиванием элементов структуры целлюлозно-бумажного материала, с ростом потенциала двойного электрического слоя на поверхности волокон под действием носителей заряда, инжектируемых в объем бумаги из коронного разряда и с образованием гетерозаряда за счет ориентации полярных группировок целлюлозы, сегментов макромолекул во время электретирования. Это подтверждается ростом ζ-потенциала волокон обеззоленных фильтров при обработке в отрицательном коронном разряде – установлено, что значение дзета-потенциала волокон электретированных обеззоленных фильтров на 18% больше, чем для исходных. Достигнутые результаты увеличения физико-механических свойств обеззоленных фильтров позволят повысить эффективность их применения., The article presents the study results of the structure and properties of paper ashless filters "Blue tape". It is shown that the "Blue tape" filter paper has a fairly high density with a relatively small number and size of voids (pores) between the fibers. When processing filters in the corona discharge field, an increase in their mechanical properties by 3.5–6% is observed, this is mainly due to the strengthening of the interfiber bond forces. The implementation of increased electrostatic bonding forces in the sheet structure leads to an increase in the resistance to the external tensile force necessary to break the paper filter. The observed dependences are associated with the orientation and ordering of the pulp and paper material structural elements, with an increase in the potential of the double electric layer on the fibers surface under the charge action carriers injected into the paper volume from the corona discharge and with the formation of a hetero charge due to the orientation of the polar cellulose groups and macromolecule segments during electreting. This is confirmed by the increase in the ζ – potential of the fibers of filters during processing in a negative corona discharge - it was found that the zeta – potential value of electret ashless filters is 18% higher than for the initial ones. The achieved results of increasing the ashless filters physico- mechanical properties will increase the efficiency of their use.

The paper presents the results of experiments to improve the performance of insulating paper as a component of high-voltage paper-impregnated insulation by introducing the modifying additive into the paper mass. Environmentally safe and economically feasible method of obtaining modifying additives of the chitin-glucan complex of Aspergillus niger (A.n.) which is a large-tonnage waste production of citric acid is proposed. The modifying additive was introduced into the paper mass in an amount of 5–10% to the mass of absolutely dry fiber of sulfate insulating cellulose. The paper samples were subjected to accelerated thermal aging at 140°C for 250 hours. The values of the short – term electrical strength of the samples with the modifying additive, both in the initial and in the aged state, exceeded the similar characteristic of the paper sample without additives. for the paper made of 100% cellulose after 250 hours of accelerated thermal aging the maximal mechanical tensile strength decreased by 2.1 times; for paper containing 5% HGC A.n. – by 1.5 times and for the insulating paper, which was introduced into 10% of the modifying additive, the specified parameter during the test has not changed. Comparative evaluation of the sorption activity of the cellulose component was carried out by determining the light transmission coefficient of transformer oil relative to the standard at the process of thermal aging. It was found that the modification of insulating paper by biopolymer also increases its sorption activity in relation to the products of destruction of paper-impregnated insulation components under the catalytic effect of copper., В работе представлены результаты экспериментов по улучшению эксплуатационных характеристик электроизоляционной бумаги, как компонента высоковольтной бумажно-пропитанной изоляции, за счет введения в бумажную массу модифицирующей добавки. Предложен экологически безопасный и экономически целесообразный способ получения модифицирующей добавки из хитин-глюканового комплекса Aspergillus niger (ХГК A.n.) – многотоннажного отхода производства лимонной кислоты. Модифицирующую добавку вводили в бумажную массу в количестве 5–10% к массе абсолютно сухого волокна сульфатной электроизоляционной целлюлозы. Образцы бумаги подвергали ускоренному термическому старению при температуре 140°С в течение 250 ч. Значения кратковременной электрической прочности образцов бумаги с модифицирующей добавкой как в исходном, так и в состаренном состоянии превосходили аналогичную характеристику образца бумаги без добавок. Введение в состав целлюлозной основы модифицирующей добавки способствовало повышению нагревостойкости бумаги, сохраняя показатель механической прочности на высоком уровне в процессе длительного термического старения: у бумаги из 100% целлюлозы после 250 ч ускоренного термического старения предел механической прочности на разрыв снизился в 2.1 раза; у бумаги, содержащей 5% ХГК А.n. – в 1.5 раза, а у бумаги, в состав которой было введено 10% модифицирующей добавки, указанный показатель за время испытаний не изменился. Сравнительная оценка сорбционной активности целлюлозного компонента проводилась путем определения коэффициента светопропускания трансформаторного масла относительно эталона в процессе термического старения. Установлено, что модификация электроизоляционной бумаги биополимером также повышает ее сорбционную активность по отношению к продуктам деструкции компонентов бумажно-пропитанной изоляции в условиях каталитического влияния меди.

The assessment of the suitability of cables of 6–110 kW with XLPE insulation in comparison with cables of the same voltage but possessing paper-oil insulation has been fulfilled on the basis of the method of multi-objective optimization that makes it possible to account not only the quantitative characteristics (of reduced costs), but also qualitative ones. As an indicator of the reliability of the cable line the maximum mean time to failure (the value inversely proportional to the parameter of succession of failures), which is an order more for cable lines with XLPE insulation than for cable lines with paper insulation, is adopted. A comprehensive assessment of the convenience of installation of cable lines revealed that the installation of cable with XLPE insulation features a 1.2–1.6 times easier installation as compared to three-wire (voltage 10 kW) and 1.4 times easier installation as compared to single-core oil-filled cables (voltage of 110 kW). The efficacy of the cables 6–110 kW with XLPE insulation is proved on the basis on the method of multi-objective optimization, that took into account as the costs for the construction and operation of cable lines and the reliability of its operation, ease of its installation and other quality indicators. If the goals taken into account are considered as equally important, the polyethylene-insulated cables for a voltage of 10–110 kW is more efficient as compared to three-wire (voltage 10 kW) and solid (110 kW) cables with paper insulation. Herewith, the cost of the cable with XLPE insulation may exceed the cost of cable with paper insulation up to two times. If the most important aim is to provide the minimum reduced costs for the construction and operation of the cable line, the use of cables with XLPE insulation for voltage of 10 kW is most advisable in individual cases.

The assessment of the suitability of cables of 6–110 kV with XLPE insulation in comparison with cables of the same voltage but possessing paper-oil insulation has been fulfilled on the basis of the criterion of reduced costs. Thus, the comparison was undertaken between cables of various design and material of insulation: three-core paper insulated ones vs. three-core XLPE insulated ones; three-core paper-insulated ones vs. solid wires with XLPE insulation; single-core oil-filled cables of 110 kV with paper insulation vs. solid wires of 110 kV with XLPE insulation. The increase in long-term permissible current loads for cables with XLPE insulation because of the larger permissible temperature of heating in comparison with cables with paper-oil insulation complies with as would increase in the cross-sectional area of cable cores (equal to 0.61 from the original) and therefore reduces the cost of the cable by reducing the cost of manufacture of conductors. The reduced costs of the construction and operation of cable lines with XLPE insulation (accounting the increase in the cost of a cable 1.2 and 2 times as compared with the cost of a cable with three-core insulation), despite the decline in the cost of manufacture of conductors and the reduced annual operating costs (9 % and 17 % respectively of cable lines of voltage of up to 35 kV and 110 kV), occurred to be more than the reduced costs of the construction and operation of cable lines with paper insulation. Currently the cost of one meter of cable with XLPE insulation is less than the cost of cables of AAB, CASB, AASv types of a voltage of 10 kV with aluminium cores, that ensures their undeniable efficacy.

A schematic and structural solution of regenerative-utilization heat use in centralized heat supply systems was previously proposed in order to increase the efficiency of operation of heating networks located in non-passable channels. The impossibility of creating a full-scale experimental setup covering the required range of factors and the area of their change, the complexity of a passive experiment on existing heating mains led to the need to develop a virtual model based on the ANSYS sofware package. A six-factor experiment has been carried out on this virtual model. Regression equations have been obtained to determine the pressure required to provide air purging of the channel, as well as heat exchange with pipelines of direct and return network water located in the channel, and heat exchange with soil around the channel. In addition, a regression relationship has been derived to find the integral heat flux from the listed washed surfaces to the air flow. The transition from dimensionless to natural factors has been made in the paper. The most significant factors are identified with the help of Pareto cards. The obtained dependencies have been verified in Part 1 of the paper. The adequacy of the obtained regression equations has been determined using standard statistical estimation methods based on the calculated values of the Fisher’s, Student’s and other criteria. The response surfaces are presented and analyzed using two dimensional sections for a number of factor values at fixed values of one and a change in two most characteristic, physically significant for a given response function. They have been validated on the basis of the analysis of regression dependencies. The obtained regression equations cover almost the entire range of possible diameters of heating mains, which makes it possible to use them in the development of energy-saving projects.

The mixed problem for the telegraph equation well-known in electrical engineering and electronics, provided that the line is free from distortions, is reduced to a similar problem for one-dimensional inhomogeneous wave equation. An effective way to solve this problem is based on the use of special functions – polylogarithms, which are complex power series with power coefficients, converging in the unit circle. The exact solution of the problem is expressed in integral form in terms of the imaginary part of the first-order polylogarithm on the unit circle, and the approximate one – in the form of a finite sum in terms of the real part of the dilogarithm and the imaginary part of the third-order polylogarithm. All the indicated parts of the polylogarithms are periodic functions that have polynomial expressions of the corresponding degrees on an interval of length in the period, which makes it possible to obtain a solution to the problem in elementary functions. In the paper, we study a mixed problem for the telegrapher’s equation which is well-known in applications. This problem of linear substitution of the desired function witha time-exponential coefficient is reduced to a similar problem for the Klein – Gordon equation. The solution of the latter can be found by dividing the variables in the form of a series of trigonometric functions of a line point with time-dependent coefficients. Such a solution is of little use for practical application, since it requires the calculation of a large number of coefficients-integrals and it is difficult to estimate the error of calculations. In the present paper, we propose another way to solve this problem, based on the use of special He-functions, which are complex power series of a certain type that converge in the unit circle. The exact solution of the problem is presented in integral form in terms of second-order He-functions on the unit circle. The approximate solution is expressed in the final form in terms of third-order He-functions. The paper also proposes a simple and effective estimate of the error of the approximate solution of the problem. It is linear in relation to the line splitting step with a time-exponential coefficient. An example of solving the problem for the Klein – Gordon equation in the way that has been developed is given, and the graphs of exact and approximate solutions are constructed.

The paper proposes an approach based on the use of mathematical methods for modeling the behavior of the designed web application and user behavior. This approach allows an evaluation of the usability of this application. The paper discusses the models of user interfaces (UI), which are used to assess the convenience of site navigation. The possibility of using two classes of UI models is shown – structural-logical (ontological) and probabilistic. Models of the first class are used to assess the degree of comprehensibility of the proposed UI navigation on the search web resource in the accepted terms. For this, mathematically defined measures of similarity between the elements of the UI and their relationships and the elements of a hypothetical (but plausible) model of the user’s perception of the search area in a given subject area are used. In particular, the paper substantiates the possibility of using Jaccard and Levenshtein lexicographic distance metrics as such measures of similarity. Probabilistic models are based on Markov chains. With the help of these models, in the presence of reliable statistical data collected during the trial operation of a web application or its prototype, it is proposed to estimate the average number of user steps required to solve a specific problem of finding information about a subject area object. The paper provides some recommendations on the use of similarity measures to improve the usability of the UI of web applications. In addition, data on the technique for estimating the probabilities of transitions of Markov chains and semantic connections are presented. To clarify the features of the UI analysis models proposed in the article, the website of the RTU MIREA Admission Committee (https://priem.mirea.ru) is provided with a fairly simple organization that provides a search for information about admission and training at the University. The application of the approach described in the paper, along with traditional methods of testing the usability of UI, will increase the overall level of usability of applications, and thereby reduce the cost of identifying and correcting related errors.

In the operation schemes of optical electronic devices (OED), such as digital autocollimators, direction finders, Shack-Hartmann sensors, as well as astro-orientation systems, projection measuring systems, geometric calibration schemes for OED, the photo-detector acts not only as a receiving device, but also as a measuring device. The tasks facing the OED photo-detectors. The solution to the problem is the use of several photo-detectors installed on one electronic board. Since OED photo-detectors act, inter alia, as measuring devices, it is necessary to perform their geometric calibration. Geometric calibration involves the measurement of interior orientation parameters used in the processing of OED images. Geometric calibration makes it possible to eliminate errors in mutual exposure of photo-detectors on one electronic board installed in the focal plane, as well as distortions introduced by the OED lens, primarily by distortion. The correctness of the interior orientation parameter determination is influenced by the relative position of the collimator, with the help of which the geometric calibration is performed, and the calibrated OED itself, i. e. the external orientation elements. The task is to separate the interior orientation parameters and the elements of external orientation. This is achieved using the method of mathematical processing of measured data in the forward and inverted positions of the collimator. This method of geometric calibration allows to use it for geometric calibration of OED with a large number of photo-detectors. The paper presents the results of the geometric calibration of the interior orientation parameters when the collimator projects a test object onto three photo-detectors of the OED layout. The factors influencing on the accuracy of the geometric calibration of the interior orientation elements for OED are determined in the paper. The developed method for geometric calibration of the interior orientation parameters for multi-matrix OED provides high measurement accuracy – not more than 0.1''–0.2''.

Introduction. The main work objective is systematization and analysis of structural defects of vacuum ion-plasma coatings; on this basis, their classification principles are developed and given in the paper. Another important part of the work is the experimental study on one of the specific defects of coatings, which the authors propose to call “defect of substructural origin”. Materials and Methods. PVD coatings of various nitride and metal systems 1.5-9.0 μm thick were used as an object of the research. Coatings were applied in vacuum installations using arc and magnetron evaporators. The research results were obtained by high resolution electron microscopy, energy dispersive analysis and indentation. Results. Various types of defects in ion-vacuum coatings are presented as the research results. They include discontinuities, deformation of crystallites, and structural inhomogeneity. The principles of their systematization are validated. It is proposed to classify defects into droplet, substructural, and growth defects (depending on the causes of their nucleation), as well as regular and stochastic ones (depending on their distribution in the coating volume). The study of “substructural defects”, classified by the authors as stochastic, is given special consideration. These micrometric defects are shaped like a cylinder with a conical “head”. Their main axle is oriented perpendicular to the surface of the coating. They can be “extruded” (tore away) by the coating. The paper validates the dislocation mechanism of their nucleation and the helicoid growth principle. Conclusions. The inference is summarized that the proposed systematization of defects in ion-plasma coatings has the character of an intermediate result of research in this scientific area. At this, the “substructural defects” do not have a fatal effect on the structure and properties of the coating due to a small size.

The paper deals with determining a temperature field of an isotropic solid with inclusion represented as a spherical layer that absorbing penetrating radiation. A hierarchy of simplified analogues of the basic model of the heat transfer process in the system under study was developed, including a “refined model of concentrated capacity”, a “concentrated capacity” model, and a “truncated model of concentrated capacity”. Each of the mathematical models of the hierarchy is a mixed problem for a second-order partial differential equation of the parabolic type with a specific boundary condition that actually takes into account the spherical layer available in the system under study.The use of the Laplace integral transform and the well-known theorems of operational calculus in analytically closed form enabled us to find solutions to the corresponding problems of unsteady heat conduction. The “concentrated capacitance” model was in detail analysed with the object under study subjected to the radiation flux of constant density. This model is associated with a thermally thin absorbing inclusion in the form of a spherical layer. It is shown that it allows us to submit the problem solution of unsteady heat conduction in the analytical form, which is the most convenient in terms of both its practical implementation and a theoretical assessment of the influence, the spherical layer width has on the temperature field of the object under study.Sufficient conditions are determined under which the temperature field of the analysed system can be identified with a given accuracy through the simplified analogues of the basic mathematical model. For simplified analogues of the basic model, the paper presents theoretical estimates of the maximum possible error when determining the radiated temperature field.

The article explores the trinitarian systems used in the natural and technical sciences. Various types of trinitarian systems are considered. A systematic analysis of trinitarian systems was carried out. The article proves that the trinitarian system is the simplest complex system. The paper examines the relationship of trinitarian systems with the theory of categories. It is shown that the trinitarian system serves as the basis for categorical analysis. The paper proves that the trinitarian system is the simplest multigraph. The trinitarian system allows transforming spaces of different curvature into each other. The trinitarian system in linear systems defines a cyclicity, which can entail: development, degradation or bifurcation. Triangulation essentially develops a trinitarian approach and can be considered as the use of a trinitarian system to solve theoretical or technical problems in areas such as, for example, psychology, social sciences, politics, geometry, and ground surveying. The general conclusion is that the Trinitarian system is a universal instrument of cognition.

Introduction. The paper considers improving the management quality of an educational organization through automating the personalized data collection, storage and ranking. The authors have developed a module of the university corporate system, an ePortfolio of students, which implements a multicriteria optimization method for calculating the students’ rating on the basis of the collected and stored data. The study object is multicriteria ranking methods. The subject of the study is the automated calculation of student’s rating within the electronic portfolio. The study objective is to develop tools for collecting, storing and processing data on individual achievements of students and the implementation of the mathematical method of multicriteria optimization for ranking students on the basis of the portfolio data. Practical implications include development of a tool for an effective management of the educational process.Materials and Methods. A prototype module of the university corporate system “ePortfolio” on the platform of 1C: Enterprise 8.3 is presented. To rank students, a special case of the alternative ranking method is implemented in the block of the data analysis module – pairwise comparison in order of their relative importance. At that, a unified scale of relations was used.Research Results. The authors described the scheme of the information system (IS) operation “ePortfolio”, presented a process interaction pattern for the portfolio formation, as well as a diagram of business processes under calculating an individual rating. A fragment of the sample is shown on which the performance of the multicriteria optimization block has been tested. The criteria of the calculations are described, as well as the rule of screening alternatives for solving for the optimum.Discussion and Conclusion. The paper presents the results of the IS block operation on ranking a list of students. The calculation results coincide with the practical data.

However, the ECP in its classical form has a number of significant drawbacks. One of them is a dependence of treatment modes and electrolyte compositions on the processed material. In addition, aggressive expensive electrolytes that require special technologies for disposal are used for ECP. Electrolytes in ECP often require heating to a temperature of 60–90 °C. Processing at such temperatures causes significant harm to the environment and production personnel. To eliminate the existing disadvantages of the ECP and expand its technological capabilities, a processing method with application of pulsed unipolar and bipolar modes has been proposed. As a result, fundamentally new processes of pulse ECP with a pulse duration of 0.05–20.00 ms have been developed. They provide a reduction of energy costs for the process and high efficiency of polishing in comparison with traditional DC polishing. The rate of smoothing micro-roughness of the treated surface related to the total metal removal is significantly increased. The use of pulse modes in comparison with traditional ECP allows processing in universal electrolytes of simple compositions based on sulfuric and orthophosphoric acids without addition of chromium anhydride. Application of the developed pulse modes, which will provide at low metal removal a significant change in surface roughness, is the most appropriate for the ECP of precise parts, products or parts of small cross-section and rigidity, such as medical devices for minimally invasive surgery, precision engineering parts, etc. The paper presents results of a study for influence of pulsed unipolar and bipolar ECP modes on the surface quality of stainless steel specimens, as well as a comparative analysis of the efficiency of using pulsed ECP modes instead of DC polishing. The technological parameters of ECP using pulsed modes, providing the highest quality surface polishing with high efficiency of micro-roughness smoothing and low energy consumption have been established in the paper.

The future nanoelectronics development involves using the smaller- -and-smaller-sized circuit components based on the micro- and nanostructures. This causes a growth of the specific heat flows up to 100 W/cm2. Since performance of electronic devices is strongly dependent on the temperature there is a challenge to create the heat transfer models, which take into account the size effect and ensure a reliable estimate of the thermal conductivity. This is one of the crucial tasks for development of new generations of integrated circuits.The paper studies heat transfer processes using the silicon thin films as an example. Thermal conductivity calculations are performed taking into account the influence of the classical size effect in the context of the Sondheimer model based on the solution of the Boltzmann transport equation.The paper, for the first time, presents and considers the influence of various factors on the thermal conductivity of thin films, namely temperature, film thickness, polarization of the phonon waves (transverse and longitudinal), velocity and relaxation time versus frequency for the phonons of different wave types.Based on the analysis, three models with different accuracy are created to estimate the influence of detailing processes under consideration on the thermal conductivity in a wide range of temperatures (from 10 K to 450 К) and film thickness (from 10 nm to 100 µm).So in the model I for the first time in calculating thermal conductivity of thin films we properly and circumstantially take into account the dependence of the velocity and the relaxation time of phonons on the frequency and polarization. The obtained values are in a good agreement with available experimental data and theoretical models of other authors. In the following models we use few average methods for relaxation times and velocities, which leads to significant reduction in calculating accuracy up to the values exceeding 100%.Therefore, when calculating the thermal conductivity for micro - and nanostructures it is necessary to employ a detailed process description of the phonons propagation for different energies (frequencies) and polarizations, and consider the real dispersion relations (velocities of their propagation) for each concerned temperature and thickness of the sample.The above recommendations can be used to estimate the in-plane thermal conductivity of thin films when simulating the new structures in advanced semiconductor devices.

This work is concerned with analysis of cross-plane thermal transfer in nanofilms.The paper presents a developed general model of phonon radiation transfer (EPRT) based on the Boltzmann transport equation. The EPRT model assumes that the thermal transfer inside a dielectric or metal medium between two metal walls is maintained at different temperatures. These walls are like heat reservoirs; their surfaces are blackbodies. The paper first presents a model of the phonon radiation transfer of the absolute blackbodies in a wide range of temperatures where a model of the ballistic thermal transfer is applicable. It conducts a comparative analysis between phonon radiation transfer and electromagnetic radiation.The basic equation is a formula to calculate a phonon radiation intensity of the absolute blackbody depending on the temperature. Therefore, the formula for the total intensity of phonons is similar to the Stefan-Boltzmann law. The main difference of phonon radiation transfer is that a value of the phonon Stefan-Boltzmann constant is affected by temperature and properties of materials (average acoustic waves in solid bodies and Debye temperature). This can be seen from the curves for Si, Ge, and Diamond.The paper presents a received analytical equation for effective thermal conductivity using a heat flux in a cross-plane direction. The results obtained show the size and temperature dependences of the effective thermal conductivity of silicon, germanium and diamond nanofilms for the ballistic transport in the cross-plane direction. Finally, the paper compares the calculated results with those of available models of different foreign authors, which are in good compliance.

Introduction. The paper deals with the calculation of wooden arches taking into account the nonlinear relationship between stresses and instantaneous deformations, as well as creep and geometric nonlinearity, are considered. The analysis is based on the integral equation of the viscoelastoplastic hereditary aging model, originally proposed by A.G. Tamrazyan [1] to describe the nonlinear creep of concrete. Materials and Methods. The creep measure is taken in accordance with the work of I.E. Prokopovich and V.A. Zedgenidze [2] as a sum of exponential functions. The transition from the integral form of the creep law to the differential form is shown. The relationship between stresses and instantaneous deformations for wood under compression is determined from the Gerstner formula, and elastic work is assumed under tension. The solution is carried out using the finite element method in combination with the Newton-Raphson method and the Euler method according to the scheme that involves a stepwise increase in the load with correction of the stiffness matrix taking into account the change in the coordinates of the nodes with the sequential calculation of additional displacements of the nodes, which are due to the residual forces. The proposed approach for increasing the accuracy of determination of creep deformations at each step provides using the fourth-order Runge-Kutta method instead of the Euler method. Results. Based on the Lagrange variational principle, expressions are obtained for the stiffness matrix and the vector of additional dummy loads due to creep. The method developed by the authors is implemented in the form of a program in the MATLAB environment. Calculation examples are given for parabolic arches simply supported at the ends without an intermediate hinge and with an intermediate hinge in the middle of the span under the action of a uniformly distributed load. The results obtained are compared in the viscoelastic and viscoelastic formulation. The reliability of the results is validated through the calculation in the elastic formulation in the ANSYS software package. Discussion and Conclusions. For the arches considered, it is found that even with a load close to the instant critical, the growth of time travel is limited. Thus, the nature of their work under creep conditions differs drastically from the nature of the deformation of compressed rods.

The analysis of scientific papers devoted to the mathematical description of electric generators of reciprocating motion with permanent magnets demonstrated that the proposed mathematical models of this type of generators are based on the theory of magnetic circuits. Such mathematical models are based on a simplified representation of the magnetic system and the magnetic field in the form of a magnetic circuit with corresponding magnetic conductivities. However, unlike traditional rotary type electric machines, electric generators of reciprocating motion have a number of features, the omission of which in mathematical modeling causes the increase of the cost of their creation (due to the duration of the design and experimental refinement of the generators). Therefore, at the initial stages of electromagnetic calculation and solving optimization problems, it is necessary to use adequate mathematical models to improve the accuracy of calculations of the parameters of these generators. For this purpose, a mathematical model based on field theory can be used; however, its main drawback is the complexity of its application for solving optimization problems. In this regard, to improve the accuracy of calculations of the parameters of electric generators of reciprocating motion with permanent magnets, it is proposed to use refining coefficients (coefficients of scattering and buckling of the magnetic flux) in mathematical models based on the theory of magnetic circuits. The authors have developed refined electromagnetic models of electric generators of reciprocating motion with permanent magnets, which make it possible to obtain the main parameters of generators at the initial stages of electromagnetic calculation and when solving optimization problems with acceptable accuracy. A distinctive feature of the refined electromagnetic models of generators is the consideration of the scattering and buckling coefficients of the magnetic flux in the magnetic system that change during the simulation.

A significant number of patents and publications in the open press show the intensity of the ongoing research to create new methods of synchronization and specialized ground-based equipment for frequency-time synchronization. The article considers the implementation of an autonomous synchronization system between ground-based satellite communication points, which is used in conditions of unfavorable reception or absence of signals from global navigation satellite systems. The paper presents studies on the assessment of the error of time synchronization of geographically separated ground points of satellite communications. The basics of constructing the receiving equipment of a radio engineering system are considered and the mutual correlation of the reference signal of the receiving equipment and the received input synchronization signal is calculated. The results of field tests of mutual synchronization equipment are presented, where the potential synchronization accuracy of equipment at ground objects with previously unknown coordinates was determined, while the synchronization equipment provided measurement of the signal propagation time from one ground object to another with the formation of universal time scales on points. The method of mutual synchronization of linked points is carried out by the duplex method at a frequency of 1065 MHz (request) and 625 MHz (response) by phase-code-manipulated signals with a base equal to 1023 and a duration of 0,1 ms.

In this paper, the spectral dependences of the transverse Kerr effect (ТКЕ) are studied experimentally and theoretically. The results are obtained for deposited and annealed samples with a corresponding variation in the size of the granules. It was found that thermomagnetic annealing leads to an increase in the ТКЕ value in magnetic nanostructures, while the most noticeable changes in the effect value were observed in the range of medium and high concentrations of the magnetic component in the visible region of the spectrum. The expediency of using the effective medium approach for calculating magneto-optical effects in granular systems, taking into account the size distribution of granules within the lognormal distribution of granules, is shown. Based on this approach, the main features of the optical and magneto-optical properties of nanocomposites are explained by the example of (Co45Fe45Zr10)X(Al2O3)1–X. All calculations are performed in the Bruggemann approximation, which effectively describes the properties of nanostructures in the region of average concentrations. Size effects are clearly manifested in nanocomposites and have a significant impact on the optical and magneto-optical properties of nanocomposites, especially in the IR region of the spectrum, which is associated with intraband transitions. Taking into account the particle size distribution makes it possible to significantly improve the description of such promising inhomogeneous nanostructures. The solved problem is very important and relevant both from the fundamental point of view – the study of magneto-optical, optical and transport phenomena in nanocomposites – and from the point of view of the great possibilities of their application in modern electronics and nanoelectronics. Taking into account the size effects and the particle size dispersion makes it possible to find new promising functional materials and control their properties in a wide spectral range.

The paper presents an analytical review of the application of biometric recognition systems in relation to facial image identification technologies. The classification of biometric systems is presented. The trends of technological progress in the field of biometrics and facial recognition capabilities are considered. It is determined that in 2020 there is a trend of transition from the use of biometric recognition technologies in traditional state security systems to the sphere of commercial and user applications. The process of «linking» encryption keys and passwords with the biometric parameters of the data subject is described. It is proposed that a biometric feature and a biometrics parameter mean a certain value that has a physical meaning that characterizes the subject itself. The possibility of using circular neighborhood and bilinear interpolation of pixel intensity values in biometrics is also presented. This will make it possible to build a local binary template. In order to solve the problem of identification of persons, it is advisable to investigate the essence of biometric systems in the technologies of identification of persons, their types, identifying the shortcomings of each of them, on the basis of which to present the directions of elimination and search for the most reliable technologies. The essence of the use of biometric systems in the technologies of identification of persons is, for example, that the user can provide the bank or other counterparty with evidence that it is he who wants to use the services on his accounts. At the same time, the demand has increased for contactless biometric solutions. These technologies are implemented in order to conduct additional biometric verification of users. This allows to minimize possible fraud or violation of the internal rules of the service, for example, the transfer of accounts of some registered users to others.

Testing of electronic devices is an integral part of the technological process of any manufacturer of such equipment. In this case, an electronic device is understood as an energy-intensive unit such as a mobile phone, data center or spacecraft. One of the key stages of testing is to identify the effect of electric fields on various electronic components of the device. This stage often requires making a mock-up of some part of an unfinished device in order to fix interference with special equipment. This requires time, financial and human resource costs. In order to reduce these costs in the modern world, the use of mathematical modeling tools for testing noise immunity and electromagnetic compatibility is becoming popular. In this paper, it is proposed to use an algorithm for visualizing electric fields in three-dimensional space and time. The algorithm is easily embedded into applications as a component of a mathematical modeling system. The work considered three ways of visualizing the electric field strength: starting from a simple setting of points in space, on the basis of which the electric field will be built, around the source of electric field radiation, to the use of algorithms that make it possible to arrange points equidistantly based on a given number of points in space for the formation of an electric field. The performance and visual implications of these methods were analyzed. The proposed methodology will be useful to the developer community as an embedded solution for point visualization of the electric field in any project in any algorithmic language with the ability to animate in time.

Introduction. Arc surfacing through feeding an additional filler wire heated by an additional arc burning between the filler wire and the electrode wire is considered. Under the conditions of such surfacing, the minimization of the input of the remelted substrate metal into the weld metal is studied. The research objectives are to examine the conditions providing self-regulation of this advanced arc surfacing process, and to evaluate control capabilities of the heat impact power on the metal and on the weld metal flow. Materials and Methods. In solving a wide range of welding and surfacing tasks, it is advisable to use engineering analysis methods based on physicomathematical modeling of processes and phenomena. These include: self-regulation of the arc process under joint melting of the electrode and the filler wires; assessment of the possibilities to control the heat impact power on the metal and on the weld metal flow during the formation of the weld The features of the arc surfacing of anticorrosive chromium-nickel steels on low-alloy steel are considered in the paper. Results. New mathematical dependences are proposed that describe physical phenomena under surfacing with an arc interaction between the electrode and filler wire. A physicomathematical model of the joint melting of the electrode and filler wire is developed. It provides determining the values of the control parameters. In addition, you can find out how much heat affects the substrate from: heat release in the main arc, droplet flows of the weld electrode and filler metal, arc plasma Discussion and Conclusions. It is established how the current and the lengths of the main and additional arcs are affected by the supply voltages. The feed rate of the electrode and filler wire with a diameter of 1.6 mm and 1.2 mm made of Inconel 625 alloy is determined. It is shown what thermal effect the substrate undergoes in this case. It is noted that due to the larger value of the main arc current, the diameter of the electrode wire should be larger than that of the filler wire. The heat flow in the substrate is created mainly by the flow of the weld metal droplets.

Objective. Integrating the numerical solution module of the kinetic equation for the droplet size distribution function in a CFD package. Application of the module to volumetric condensation at the supersonic flow of a vapor-gas mixture through a nozzle in a two-dimensional formulation, comparison of the results with experimental data of third-party authors.Methods. In this paper, the problem of volume condensation in the supersonic flow of a vapor-gas mixture through a nozzle is solved by finite element methods in a two-dimensional formulation using user-defined functions.Results. A module for the numerical solution of the kinetic equation for the droplet size distribution function is presented as a user-defined function integrated into the calculated CFD package.Conclusion. The module application to volumetric condensation for a vapor-gas mixture flow through the nozzle gave a qualitative agreement in all areas and a quantitative agreement in the area of intense condensation with measurement data. The distributions of temperatures, pressures, and the degree of supersaturation are presented both along the central axis and on the plane bounded by the contour of the computational domain. It is shown that the module does not depend on the solver type (stationary or non-stationary).

Preference is given to cable lines with cross-linked polyethylene insulation in electrical networks with a nominal voltage of 10 kV during reconstruction of existing and construction of new industrial enterprises. The standard service life of such cables is at least 30 years (subject to the conditions of storage, transportation, installation and operation), and the actual one is determined by the technical condition of the cable. The service life of a cable line depends on the state of its insulation, the aging of which occurs under the influence of several factors. Conventionally, all factors influencing one or another degree on the cable insulation resource can be divided into thermal, electromagnetic, climatic, mechanical and operational. The most significant reason for the insulation aging is high temperature, which accelerates the reaction of thermo-oxidative destruction, during which high-molecular polymer compounds decompose. In fact, cables are operated at temperatures below the long-term permissible values, and, therefore, the aging of the insulation is slower, and the actual service life will be longer than the standard. At present, condition of the insulation is monitored with the use of high voltage tests related to destructive testing methods. When designing and operating cable lines, it is necessary to estimate the duration of the actual service life under various operating conditions. In theory, there are several expressions for calculating the service life of a cable line when exposed to temperature, humidity, electric field and aggressive environments, but all of them are not applicable in practice due to the presence of a large number of coefficients whose values are unknown. The paper presents an analytical expression obtained for determining the service life of power electric cables, taking into account the aging of the insulation under the influence of temperature and electric field.

Introduction. In all types of digital communication, error control coding techniques are used. Many digital communication standards, such as Wi-Fi and 5G, use low density parity check (LDPC) codes. These codes are popular because they provide building encoders and decoders with low computational complexity. This work objective is to increase the error correcting capability of the well-known bit-flipping decoder (BF) of LDPC-codes. For this purpose, a modification of the decoder is built, which enables to dynamically control one of its main parameters whose choice affects significantly the quality of decoding. Materials and Methods. The well-known bit-flipping decoder of binary LDPC-codes is considered. This decoder has several parameters that are not rigidly bound with the code parameters. The dependence of the decoding quality on the selection of the output parameters of the bit-flipping decoder was investigated through simulation modeling. It is shown that the decoding results in this case are significantly affected by the input parameter of the decoder — threshold T. A modification of the BF-decoder of binary LDPC-codes has been developed, in which it is proposed to set the threshold dynamically during the execution of the algorithm depending on the error rate. A comparative analysis of the error- correcting capability of decoders is carried out by the simulation modeling method. Results. A lemma on the maximum value of the decoder threshold T is formulated and proved. Upper bounds for the number of operations are found for the original and modified decoders. A simulation model that implements a digital noise-immune communication channel has been built. In the model, the initial data is encoded with a given LDPC-code, then it is made noisy by additive uniformly distributed errors, and thereafter, it is decoded in turn by the bit-flipping algorithm with different threshold T parameters, as well as by a modified decoder. Based on the input and output data, the correction capacity of the decoders used is estimated. Experiments have shown that the error-correcting capability of the modified decoder in the range of the real error rate is higher than that of the original decoder, regardless of the selection of its parameters. Discussion and Conclusions. The lemma, proved in the paper, sets the upper bound on the threshold value in the original decoder, which simplifies its adjustment. The developed modification of the decoder has a better error- correcting capability compared to the original decoder. Nevertheless, the complexity of the modification is slightly increased compared to the original algorithm. It has been pointed out that the decoding quality of a modified decoder develops with a decrease in the number of cycles in the Tanner graph and an increase in the length of the code.

The total probability formula for continuous random variables is the integral of product of two probability density functions that defines the unconditional probability density function from the conditional one. The need for calculation of such integrals arises in many applications, for instant, in statistical decision theory. The statistical decision theory attracts attention due to the ability to formulate the problems in a strict mathematical form. One of the technical problems solved by the statistical decision theory is the problem of dual control that requires calculation of integrals connected with the multivariate probability distributions. The necessary integrals are not available in the literature. One theorem on the total probability formula for vector Gaussian distributions was published by the authors earlier. In this paper we repeat this theorem and prove a new theorem that uses more familiar form of the initial data and has more familiar form of the result. The new form of the theorem allows us to obtain the unconditional mathematical expectation and the unconditional variance-covariance matrix very simply. We also confirm the new theorem by direct calculation for the case of the simple linear regression.

The changes of distances less than ~10–21 are registered during the gravitational wave experiment. This feature determines the minimum size of experimental installations and the frequency range of gravitational wave detectors. To expand the frequency range and increase the sensitivity of gravitational interference detectors, it is necessary to increase the linear dimensions of the detector significantly as big as Earth and even more. The Republic of Belarus has experience in the development, launch and operation of satellites, the use of which can significantly increase the linear dimensions of the gravitational space detector. The satellite systems as a space detector of gravitational waves S-LIGO-NxR-zy are considered. The S-LIGO-NxR-zy space gravitational wave detector is a system of laser interferometers consisting of x number of satellites with given z-type orbits, in orbit of planet N of the solar system. The interferometers in such systems are identical to interferometers with oscillating mirrors due to the complex satellite motion. The purpose of this work is to study the influence of the kinematic parameters of satellites on the detected signal in the S-LIGO-E2R-z2 system. The configuration of the space detector determines the set of satellite orbits, direction and initial phase of movement. The detector signals depend on the instantaneous distance between the satellites and can be described as periodic functions. There are obtained the equations that describe the periodic changes in the signal between satellites as a result of their relative motion, depending on the initial conditions for launching the satellites. The general case for arbitrary oriented orbits and two special cases for collinear and orthogonal circular orbits in space gravitational wave detectors S-LIGO-E2R-z2-p and S-LIGO-E2R-z2-o are considered in the paper. The graphs of the dependences of the detected signal on the kinematic parameters of the satellites of the detectors S-LIGO-E2R-z2-p and S-LIGO-E2R-z2-o are presented. It is shown that the detected signals contain sections of zero intensity, and the duration and frequency of sections of zero intensity are related to the kinematic parameters of satellites.

The paper presents a method for minimizing the torque value of the multi-time deploymentfolding hinges. The objects of research were the hinges assembly of multi-time deployment-folding mechanical devices of solar array, which are used as part of the platforms of spacecraft. A computational analysis of the forces and moments that act in the hinges in the process of their opening and folding is carried out. The minimization of the excessive torque value without changing the design and layout of the hinge is possible by changing the shape of the dependence of the spring drive force on the angle of rotation of the hinge. The possibility of using constant force springs as part of the hinge is considered, the existing design algorithms are improved and a program for calculating the geometric and mechanical characteristics of constant force springs is developed. Experimental data were obtained for measuring the forces of springs of various configurations, showing the dependence of the magnitude of the force on the magnitude of the spring deformation and confirming the efficiency of the proposed calculation algorithm. A prototype of a hinge assembly with a constant force spring drive was developed and manufactured. The possibility of minimizing the excess torque without the need to change the design of the hinge while maintaining its technical characteristics was experimentally confirmed.

Introduction. The issue of the global educational crisis was outlined by Ch. P. Snow and denoted by Ph. H. Coombs more than sixty years ago. The viewpoints on this problem outspoken ever since are diversified, but it did not lead to blunting of acuteness thereof. It gives the evidence of the necessity to go on revealing and studying the reasons creating the global educational crisis, of which the rapid growth of scientific knowledge and its accelerated differentiation are outlined by researchers as primary ones. It determines the topicality of researching the structure of scientific knowledge, which is a determinant of the basic education content through the lens of the history of science.The aim of the present study is substantiating of the idea that the basic reason of the world educational crisis is a result of strengthening of scientific knowledge differentiation due to acceleration of its volume growth and developing the approach to overcome the crisis.Methodology and research methods. The methodology of the study is based on the ideology of F. Klein (the Erlangen programme) and the ideas of E. Wigner about the levels of division of the scientific knowledge field (the totality of these ideas allows using them as a tool for description of the scientific knowledge structure and, consequently, of the structure of the education content, the determinant whereof it is); on the personal-activity approach developed by V. S. Lednev for the analysis of the structure of the education content, and on the approaches to description of the behaviour of complex systems on the base of regular laws established by synergetics.Results. Examining the history of development of the scientific knowledge structure within the ideology of F. Klein’s Erlangen programme allowed coming to the conclusion that in general it should be described as a result of the non-completed process of formation of the pattern of dividing the entire scientific knowledge field into three areas constituting three levels: phenomena of nature, laws of nature and the field of symmetry principles. In proportion to growing, each next level provides the previous one with its structure. The currently accepted classification of sciences is a horizontal section of the three-level pattern of dividing the scientific knowledge in the field of laws of nature.Scientific novelty. The paper evidences that the three-level pattern of dividing the scientific knowledge is formed in the course of the history of science as a basis of integration of the scientific knowledge, equalising the process of its differentiation, which shall allow optimising the content of general education with strengthening the integration of its disciplines.Practical significance. The ideas of the scientific knowledge structure, inherent to the three-level pattern of dividing the scientific knowledge, will be utilised as the basis for the formation of a new variant of the general education content structure, which will allow optimising it and mitigating the acuteness of the global educational crisis related to the progressing differentiation of scientific knowledge.

The article carries out an analysis of the competitiveness of the Russian space industry in the international space services market according to the following indicators: the volume of budget of national space organizations, the volume of the commercial space exploration market, the number of space launches, positions in manned cosmonautics, production of spacecrafts, deep space exploration, staffing of the space industry and international integration in the space sphere. The paper conducts a SWOT-analysis of the Russian space industry. Its main strengths are: leading positions in manned cosmonautics, leading positions in the number of space launches per year, and extensive experience in space exploration. The greatest concern is caused by: the lack of development of space robotics, insufficient programs for the development of deep space, financial problems and the private sector of Russian cosmonautics, which is in its infancy. The author substantiates the necessity of reforming the Russian space industry.

The study of ultrafast laser interaction with graphene-like materials based on transition metal dichalcogenides attracts most scientific groups. It is connected with potential use of these materials in flexible optoelectronic devices of visible and THz range. In this paper the parameters of generation of terahertz field from the surface of bulk layered crystal and monolayer film of tungsten diselenide are analyzed. Generation of terahertz radiation from the surface of experimental samples was studied by the terahertz time-domain spectroscopy in reflection geometry. Bulk layered crystals of tungsten diselenide were grown by gas transport reactions. Monolayers of tungsten diselenide crystals were grown by chemical vapor deposition on a silicon substrate. The bandwidth of the generated terahertz radiation from the surface of the bulk layered tungsten diselenide crystal was ~ 3.5 THz. For tungsten diselenide monolayer the spectrum bandwidth of the generated THz radiation was ~ 2.5 THz. The peak amplitude of the generated terahertz field for both samples was at a frequency of ~ 1 THz. Research of the influence of the angle of rotation of a polarization plane of optical femtosecond pump on peak-to-peak amplitude of the generated terahertz field from the surface of investigated samples was carried out. Symmetry analysis of the azimuthal dependence of THz radiation made it possible to separate the mechanisms of THz radiation and evaluate their contribution. The analysis results confirm that the only possible contribution to the generation of terahertz radiation in a tungsten diselenide monolayer crystal is the second order nonlinear optical effect – optical rectification. One of the contributions to the generation of tungsten diselenide is a nonlinear-optical effect of the third order – surface optical rectification.

The paper addresses the problem of assessing the quality of fingerprint images using spatial analysis methods. The author proposes using the previously developed mathematical model to describe the set of magnitudes of the image gradient. The model is based on the two-parameter Weibull distribution. The author proposes two approaches to assess the quality of fingerprints. The first approach is implemented by the so-called “Full reference method”, which compares the Weibull distribution parameters’ values of statistical estimates. The results of identifying sweat pores using this method are presented. The second approach is called the “No-Reference method” and is used to assess fingerprints’ quality when analyzing and identifying the information content of their individual sections. It is proposed to use an image blur map as a quality characteristic and a statistical estimate of the Weibull distribution shape parameter as a measure of the blur. The shape parameter is estimated at each image point by the combination of magnitudes of the image gradient in the vicinity of the point; in this, the previously developed blur mapping technique is applied. The specific examples illustrate effectiveness of the proposed approaches.

The paper shows the approach and the result of taking into account the mutual influence of on-board subsystems of a complex technical object along the DC power supply circuits. Technical objects are understood as a mobile, energy-intensive vehicle, such as an aircraft, a surface or submarine vessel, or a railway locomotive with strong magnetic fields. The aim of the work is to create a simple and intuitive tool for mathematical modeling of the magnetic field vector at an arbitrarily specified observation point. The task is being solved in order to improve the accuracy of magnetic measurements on board, in particular, in navigation problems. On-board DC networks are considered, to which the approach of mathematical modeling is applied. The disadvantages of commercial programs of a similar purpose are noted. The binding of the objects under consideration to the general coordinate system is described. An analytical algorithm for calculating the magnetic field vector from the on-board cable network with a pronounced 3D trajectory is shown. Examples of visualization of the simulation results are given. An algorithm for calculating the induction vector based on the Biot-Savard law is considered. The algorithm for the analytical solution of the problem is described in detail. A specific power cable of the on-board network is considered. The cable is given by a set of straight conductors with current. The ways of future improvement of the created product with the transition from one observation point to the field map in a given three-dimensional zone of arbitrary position, volume and orientation are outlined. The obtained result is considered as an element of the procedure for achieving electromagnetic compatibility of energy-intensive and highly sensitive subsystems of a modern complex technical object.

Introduction. Improving the quality and operational reliability of welded structures of power equipment is an urgent task of welding production. Its solution is possible on the basis of the development or selection of advanced methods and technologies of electroslag welding (ESW), which eliminate the causes of the formation of tempering cracks (TC) in thick-plate welds. This paper considers a comparative assessment and recommendations on the selection of such advanced ESW methods. The work objectives are to solve the problem of forming a fine-grained, uniform, crack-resistant metal structure of a welded joint with high mechanical characteristics and to reduce the negative impact of the ESW thermal cycle on the base metal. The solution to this problem is possible on the basis of a reasonable choice of methods and technologies for ESW with regulated (controlled) thermal cycle. Materials and Methods. A comparative analysis of advanced methods and technologies of ESW with a controlled thermal cycle is carried out; a comparison of their pros and cons is provided; practical recommendations on the selection of advanced methods for controlling the thermal cycle parameters are offered. Results. It is shown that moderate heat input at high-speed ESW in a narrow gap provides a single pass to form a welded joint with a finer-grained structure and high mechanical properties compared to the in-house technologies of ESW and automatic submerged-arc welding. Recommendations for practical use of the method in welding production are given. Discussion and Conclusions. The results obtained are recommended to be used in the development of ESW technology for thick-sheet welded structures of nuclear and thermal power equipment that enables to abandon postwelding heat treatment (normalization and high tempering).

Introduction. The paper considers an actual issue of the development and application of a non-destructive method for controlling the quality of surfaces of steel products (Kelvin probe method). The work objective is to establish the magnitude of the contact potential difference (CPD) of steel 107WCR5 after heat treatment. Materials and Methods. The object of study is alloy tool steel 107WCR5. The chemical composition of the samples was refined through the optical emission analysis method. To carry out the statistical processing, there were three samples in three series. We chose different heat treatment modes for each series, i.e., quenching with low tempering, strengthening and normalization. The end surfaces of the samples were polished and then one of them was treated with a solution of nitric acid. Further, the measurement of the contact potential difference and statistical data processing were carried out. Results. The data obtained show that the CPD value of steel 107WCR5 samples changes after heat treatment. With an increase in tempering temperature, the contact potential difference of the polished surface and the hardness, decrease almost linearly. Exposure to acid causes a significant decrease and equalization of the contact potential difference for all structures. The contact potential difference of steels 107WCR5 and CT105 is compared. Alloying steel by the elements with the work function values of the electron higher than that of iron causes a decrease in the CPD between the standard and the sample. The CPD behavior under a change in the composition of the steel depends strongly on the presence of alloying elements. The dependence of CPD on the dispersion of the structure is seen in both cases; however, it is more pronounced for 107WCR5 steel. The electron work function of the martensite, troostite, and sorbitol structures obtained as a result of heat treatment of steels 107WCR5 and CT105 is calculated. Discussion and Conclusions. The dependence of the contact potential difference on the structure, chemical and phase composition was experimentally established; the electron work function of steels 107WCR5 and CT105 was calculated. This technique is more sensitive to alloy steel samples than to carbon steel. It seems possible to conclude that the measurement of the contact potential difference can be used to control surfaces exposed to active media or elevated temperatures as a non-destructive express diagnostic method.

Semiconductor industry calls for emerging memory, demonstrating high speed (like SRAM or DRAM), nonvolatility (like Flash NAND), high endurance and density, good scalability, reduced energy consumption and reasonable cost. Ferroelectric memory FRAM has been considered as one of the emerging memory technologies for over 20 years. FRAM uses polarization switching that provides low power consumption, nonvolatility, high speed and endurance, robust data retention, and resistance to data corruption via electric, magnetic fields and radiation. Despite the advantages, market share held by FRAM manufacturers is insignificant due to scaling challenges. State-of-the-art FRAM manufacturing is studied in this paper. Ferroelectric capacitors and memory cells made by main commercial FRAM manufactures (Texas Instruments, Cypress Semiconductor, Fujitsu и Lapis Semiconductor) are explored. All memory cells are based on the lead zirconate titanate PZT capacitor with the thickness of about 70 nm and IrOx/Ir or Pt electrodes. The leading FRAM technology remains the 130 nm node CMOS process developed at Texas Instruments fabs. New approaches to further scaling and new devices based on ferroelectrics are reviewed, including binary ferroelectrics deposited by ALD techniques, piezoelectronic transistors, ferroelectric/2D-semiconductor transistor structures, and others. Whether FRAM technology will be able to resolve one of the main contradictions between a high-speed processor and a relatively slow nonvolatile memory depends on the success of the new technologies integration.

Introduction. Microdefects and zones with stress concentration in welded joints cause fatigue macrocracks. Such damage is potentially dangerous, especially if the fatigue life of the structure is almost exhausted. In this case, the crack size is close to the critical value, and it is crucial to determine its length. The paper considers the development of an engineering analytical model for assessing the critical crack length and endurance limit of welded joints with the formed grain in the structure of ferrite-pearlitic steels after welding. Materials and Methods. The theory and methods of fracture mechanics at the mesoscale are used. A simple analytical dependence is obtained, which provides determining the critical dimensions of a macrocrack for ferrite-pearlite steels without using the Griffiths formula. . The calculation results of the critical crack lengths of various steels depending on their yield strength are presented. An analytical dependence of the endurance limit calculation for the most dangerous symmetric loading cycle, according to the standard set of mechanical characteristics and the average grain diameter of ferrite-pearlite steel, is presented. Results. Structural deformation analysis of the crack propagation process has been performed. On its basis, an engineering technique for assessing the endurance limit is developed. A mathematical model that enables to calculate the endurance limit and the critical crack length in the components of welded assemblies of large-sized facilities, considering periodic loads of a symmetrical cycle, is developed. Using this model, it is possible to estimate the degree of metal sensitivity to the original characteristics (yield stress, Poisson's ratio, grain diameter, relative constriction, Young's modulus, power-law hardening coefficient, etc.). Discussion and Conclusion. Under stresses corresponding to the steel endurance limit, the critical crack opening rates of the tip and edges approach each other. Energetically, this moment approximately corresponds to the transition of the crack to an unstable state. The accumulation of one-sided plastic deformations causes the limiting state of plasticity of the region adjacent to the crack tip and its avalanche-like or sharply accelerated motion. This critical area is interrelated with the grain diameter of the material, the characteristic of critical plasticity and the critical opening at the crack tip at the fatigue limit. The proposed analytical dependences can be used to assess the residual life and the fatigue limit of welded structures, the influence of various factors on the fatigue limit of welded joints of ferrite-pearlitic steels used in mechanical engineering, shipbuilding, pipeline transport, etc

Current trends in the design of electronic systems is the use of embedded systems based on systems on a chip (System-on-Chip (SoC)) or (VLSI SoC). The paper discusses the design features of electronic systems on a chip using the SystemC design and verification language. For the joint design and simulation of digital systems hardware and software, seven modeling levels are presented and discussed: executable specification, disabled functional model, temporary functional model, transaction-level model, behavioral hardware model, accurate hardware model, register transfer model. The SystemC design methodology with functional verification is presented, which reduces development time.The architecture of the SystemC language and its main components are shown. The expansion of SystemC–AMS for analog and mixed analog-digital signals and its use cases in the design of electronic systems are considered. Computing models are discussed: temporary data stream (TDF), linear signal stream (LSF) and electric linear networks (ELN). The architecture of the SystemC–AMS language standard is shown and examples of its application are given. It is shown that the design languages SystemC and SystemC–AMS are widely used by leading developers of computer-aided design systems for electronic devices.

Currently, due to the increase in the average speed of vehicles to ensure their visibility, the luminous intensity of their lightning equipment is constantly increasing, that can lead to blindness of other road users, especially at night. On the other hand, if you do not increase the luminous intensity if lanterns, a vehicle will not be noticeable in difficult road conditions (fog, rain, dust) and it can cause an accident. To eliminate this contradiction, a fundamentally new modular design of the adaptive rear combined vehicle light with non-replaceable light sources based on single powerful light emitting diodes and effective secondary optics of large diameter has been developed in the paper. The design provides for the use of an integrated microcontroller to control luminous intensity of its lights, depending on the conditions of external illumination, braking dynamics of a car and surface condition of a lamp diffuser with the possibility of transmitting data via a CAN-bus. Thanks to the built-in microcontroller, the developed flashlight is suitable for installation on vehicles without an on-board computer. These properties allow the flashlight to ensure visibility of a vehicle, and to avoid blinding the remaining road users. The design of the adaptive lamp is small in thickness (up to 40 mm), high luminous efficiency (at least 85 %) and reliability. The conducted lightning tests have shown that the developed lamp fully complies with UN Regulation No 6, 7, 23, 38, 48. The design has been compared with existing analogues of foreign production, which showed that such a lamp consumes less energy (30 %) and has a lower probability of failure due to the use of high-power LEDs used as a light source.

Introduction. One of the main elements of the safe operation of gravity roller conveyors used in pallet racks is a brake roller. The most promising design is the brake roller magnetic (eddy current) type. The operation principle of such rollers is based on the laws of electromagnetic induction and involves the braking of a conductor moving in a magnetic field, due to the interaction of eddy currents (or Foucault currents) arising in the volume of the conductor with an external magnetic field. However, in the market of warehouse shelving equipment, brake magnetic rollers are not widely used due to their high cost, which is primarily due to the lack of domestic designs and methods for their calculation. The aim of the work is to develop a mathematical model of the moving pallets process on a magnetic type brake roller.Materials and methods. The paper presented the theoretical study results on the development of a mathematical model of the moving pallets process on a magnetic type brake roller, described in works on centrifugal friction rollers and eddy current brake devices.Results. The main parameter determining the functions of the brake magnetic roller and hence the speed of the pallet along the gravity roller conveyor is a magnetic viscosity coefficient. The speed dependence of the pallets on the brake magnetic roller for various values of a magnetic viscosity coefficient is determined, its analysis is carried out.Conclusions. A mathematical model of the moving pallets process on a brake magnetic roller is developed. The movement speed equation of the pallets on the brake magnetic roller is obtained. For a reasonable choice of the design parameters of the magnetic brake roller, experimental studies are required to determine a magnetic viscosity coefficient.

The Harry Dym equation is the third-order evolutionary partial differential equation. It describes a system in which dispersion and nonlinearity are coupled together. It is a completely integrable nonlinear evolution equation that may be solved by means of the inverse scattering transform. It has an infinite number of conservation laws and does not have the Painleve property. The Harry Dym equation has strong links to the Korteweg – de Vries equation and it also has many properties of soliton solutions. A connection was established between this equation and the hierarchies of the Kadomtsev – Petviashvili equation. The Harry Dym equation has applications in acoustics: with its help, finite-gap densities of the acoustic operator are constructed. The paper considers a generalization of the Harry Dym equation, for the study of which the methods of the theory of finite-dimensional dynamics are applied. The theory of finite-dimensional dynamics is a natural development of the theory of dynamical systems. Dynamics make it possible to find families that depends on a finite number of parameters among all solutions of evolutionary differential equations. In our case, this approach allows us to obtain some classes of exact solutions of the generalized equation, and also indicates a method for numerically constructing solutions.

This article focuses on gender discourse genesis in the context of both a new feminist movement and the emergence of feminist linguistics. The process of feminist linguistic theory conversion into the feminist social and political practices has also been revealed in the paper. German universities committed to all-European academic cultural tradition differed greatly from other European educational institutions by the number of women in the academic community. The low women representation in German academic environment is due to the following several factors:- academic institutions do not compete with each other for future students;- professionalization of science, achievements in scientific researches have caused the high status of a scientist in the German society, as well as the prestige of the academic career;- the academic career has become attractive for social elites;- the university boom has led to a dramatic increase of the number of female students and the number of women in the academic staff as well.These have resulted in the re-evaluation of a woman’s place and role in the society including the language structures and reflected by the academic discourse practices and notably in the so called geschlechtsgerechte Sprache, i. e. “equity in languages” principles.

The paper analyzes the condition of additivity of the information and reference kiosk, which allows designing a static kiosk, which is essentially a set of pages organized in order to provide users with reliable information in various fields of knowledge and practice, with additive properties. The condition of additivity is analyzed based on the loading time of the pages of the informational kiosk is implemented on the basis of the concept of a simple website with narrow subject matter by adding the concept of a vertical portal, in connection with which introduced the concept of optimal page load time of the informational kiosk, since the main task of the informational kiosk is the display of the user requested page containing the content within a certain time interval, and a key component of the kiosk GUI. Information and reference kiosk, as a small subscriber system in terms of functionality and volume of content, containing information in text, audio or video format, aimed at providing reference information to the user and giving him a means of interaction, by providing all available system objects and functions implemented in the form of graphical components, is not an exception. The article also discusses the key concepts of the information and reference kiosk, such as additivity, ergodicity, and entropy.

The active development of the mobile platforms sector such as smartphones, smart watches, fitness bracelets and other wearable electronic devices in the last 4 years has caused a huge growth of the market of mobile applications-services. Western countries are actively implementing mobile applications-services for household energy users. In Belarus, there is a positive dynamics in the number of active users of applications-services, every year it is possible to attract 7 % of unique customers. In the present paper the experience of implementation and operation of the mobile application for power systems is analyzed. The dynamics of the market of mobile applications-services has been traced: the amount of time spent by the person in interaction with the device was determined as well as the total expenditure of funds in the application at the moment; also, the growth of expenses within the applications was forecasted. The potential benefits for business and end-users of services from the implementation of mobile applications-services were demonstrated. Their properties, main qualities and advantages over traditional methods of “business – client” interaction are considered. A number of features needed for the successful functioning of the mobile application in the power system of Belarus are identified. The process of creating software for smart devices has been studied and the functionality needed by the mobile application for the power system has been proposed for attracting new users. A special algorithm for the launch and successful “life cycle” of a mobile application has been proposed. It allows to operate and develop mobile applications-services as efficiently as possible, as well as to avoid the most common errors at the stages of their development and launch. The implementation of a mobile application in the power system of the Republic of Belarus, in the long-term, will significantly increase customer loyalty, simplify interaction with users, make it possible to build new models of distribution of electricity, and, consequently, regulate the demand for energy resources.

In design activities, technical solutions are practiced, which provide for the use of different tension strings of insulators in a single span. The present paper considers the calculation of the sag and load factors for a span with two different tensioning insulator strings that are of identical suspension heights. The system of “the first tension insulators string – the wire – the second tension insulators string” was described by the equations of a parabola. A relationship has been established between the sag increase factor and the coefficients that take into account the presence of tensioning insulators strings. The resulting compact formula for sag increase is generally suitable for any combination of strings in a span. The coincidence of the calculation is shown for particular cases known from the literature. The formula for calculating the load factor for the equation of state was derived, taking into account the presence of different strings in the span. The reliability of the formula has been proved by the coincidence of results for particular cases of the arrangement of strings. The obtained expressions can be used both for vertical (weight and ice) loads and for horizontal (wind) ones. In the case of loads in two planes, the equation of state must take into account all the components when calculating the resulting reduced load on the wire along the inclined plane. Calculations were performed for different lengths of spans of switchgear with different wires and strings of insulators. A span with one and two tensioning strings of insulators, with the same suspension heights, in the absence of wind and ice is considered. The curves of the sagging wires to different strings have been plotted. It is demonstrated that when calculating sags and tensions, the difference between strings must not be neglected.

Introduction. Rubber bushings are important parts of the spring systems of modern vehicles. The properties determine not only the comfort of car movement, but also affect the elastic suspension characteristics. When a bushing is deformed, linear sections appear in characteristics. It is advisable to describe such characteristics using a mathematical model based on the classical elements of Hooke and Saint-Venant. The paper presents a mathematical description of the bushing simulation functioning results, accuracy of approach, areas of application of the mathematical model.Materials and methods. The initial data was the experimental characteristic of a cylindrical automobile rubber bushing, obtained in harmonic mode at the 0.03 to 51 Hz frequency and the 0.4 to 10 mm amplitude. The force balance of the two Hooke elements and one Saint-Venant element interacting with each other determined the mathematical model description. The authors carried out the calculations using numerical and optimization methods.Results. As a result, the authors determined functions characterizing the change in the parameters of the Hooke and Saint-Venant elements from the rubber bushings’ deformation amplitude. Moreover, the authors calculated power characteristics in the form of dependences of the rubber bushing effort and also found quantitative indicators of the reliability of the experimental data approximation by the developed mathematical model.Discussion and conclusions. The analysis of the operating modes shows the possibility of the model application to describe the rubber bushing functioning in a stationary harmonic mode with small and medium strain amplitudes. The simulation results of the Hooke’s and Saint-Venant’s parameters reveals the theoretical prerequisites for the possibility of using the model to calculate the bushing force in an unsteady mode.The authors have read and approved the final manuscript. Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

The paper studies linear differential operators in derivatives with respect to one variable. Such operators include, in particular, operators defined on infinite prolongations of evolutionary systems of differential equations with one spatial variable. In this case, differential operators in total derivatives with respect to the spatial variable are considered. In parallel, linear differential operators with one independent variable are investigated. The known algorithms for reducing the matrix to a stepwise or diagonal form are generalized to the operator matrices of both types. These generalizations are useful at points, where the functions, into which the matrix components are divided when applying the algorithm, are nonzero.In addition, the integral operator is defined as a multi-valued operator that is the right inverse of the total derivative. Linear operators that involve both the total derivatives and the integral operator are called integro-differential. An invertible operator in the integro-differential sense is an operator for which there exists a two-sided inverse integro-differential operator. A description of scalar differential operators that are invertible in this sense is obtained. An algorithm for checking the invertibility in the integro-differential sense of a differential operator and for constructing the inverse integro-differential operator is formulated.The results of the work can be used to solve linear equations for matrix differential operators arising in the theory of evolutionary systems with one spatial variable. Such operator equations arise when describing systems that are integrable by the inverse scattering method, when calculating recursion operators, higher symmetries, conservation laws and symplectic operators, and also when solving some other problems. The proposed method for solving operator equations is based on reducing the matrices defining the operator equation to a stepwise or diagonal form and solving the resulting scalar operator equations.

Introduction.Precision elements of the target equipment and sensitive elements of the stabilization and orientation system of the advanced spacecraft are considered in the framework of this research. A method and software for modeling the dynamic characteristics of these elements are developed and validated. At that, the processing data results from the experimental studies on active and passive oscillators are taken into account.Materials and Methods. It is shown how the method of weightlessness provides simulation of the conditions that as much as possible conform to the real-time use of advanced space vehicles, precision structural elements, target equipment and their drives. Schemes of the corresponding experimental facilities are presented. Mathematical modeling methods, techniques of machine mechanics and dynamics are applied. Basic parameters of the proposed design dynamics, which are governing parameters in terms of the implementation of the target functions of the spacecraft, are calculated. Rational versions of layout and approximate cycle patterns of the operation of advanced space vehicles are formed to reduce microperturbations from driving gear with rotating masses.Research Results. A simulation technique for the dynamic characteristics of the drives of advanced space vehicles considering the regular oscillator operation is developed and validated. A complex of methods is presented for solving the problems of identifying dynamic parameters of a mathematical model of an advanced spacecraft based on the processing data results obtained through the experimental testing of active and passive oscillators. Two types of vibration from flywheel engines are noted. The first type is according to the commands of the position control and stabilization control system. The second type is due to residual imbalance from the solar constant meter. It is shown how these vibrations affect the dynamic characteristics of the gyro mounting seats and of the multispectral scanner for hydrometeorological support of the spacecraft. The data obtained are meant to solve the problems of assurance of the dynamic accuracy of advanced space vehicles.Discussion and Conclusions. A technique for modeling the dynamic characteristics of advanced space vehicles when operating in the precision orientation mode is proposed. The solution is based on the results of theoretical and experimental studies presented in the paper, and it considers the operation of standard oscillators. The implementation of this method is brought to software and algorithmic support for assessing the dynamic characteristics of standard oscillators of an advanced space vehicle. Recommendations to reduce the effect of active oscillators are established. Initial data are selected to determine the dynamics of advanced space vehicles from the point of view of fulfilling their target functions. The layout and approximate cycle patterns of the operation of advanced space vehicles to identify the driving gear with rotating masses as sources of micro-perturbations are proposed.