bluuebunny/crossref_metadata_2025 huggingface dataset:
Unusual spin dynamics
Authors: Zhumaev Mustakim R , Sharipov Mirzo Z , Rizoqulov Mirzokhid N
Published: December 2022

The paper considers the dynamics of a spin when it is simultaneously affected by a constant magnetic field directed along the Z axis and a variable one applied to the X0Y plane. It is shown that coupled oscillations of all components of the magnetic moment (or magnetization) arise in this case. In other words, it becomes possible to control the orientation of the magnetic moment. Further, it was found that this possibility remains even in the case of two constant magnetic fields - when they are perpendicular to each other.
Study of the magnetic properties of nanostructural metal complexes of chitosan
Authors: Ashurov N Sh , Yugai S M , Atakhanov A A , Vakhidova N R , Rashidova S Sh
Published: December 2022

Nanostructured polymeric metal complexes based on chitosan with Co2+, Mn2+, Cu2+have been obtained. The role of the precipitant in the formation of nanoparticles with certain sizes is shown. Optimal morphologies for the creation of new and promising nanostructured metal-polymer materials with magnetic properties have been identified. A correlation has been established between the magnetic characteristics of polymeric metal complexes based on chitosan with metal ions of the 3-d transition series with their structural features.
Electric voltage redistribution effect in Schottky barrier structures based on Si under hydrostatic pressure
Authors: Khamidov R , Mamatkarimov O
Published: December 2022

The paper presents the results of strain-effect studies in diode structures with Schottky barrier made on the basis of n-Si and n-Si with resistivities 102 - 105 Ohm·cm under all-round hydrostatic pressure. It is shown that as the resistivity of the base area of the structures increases, its rectifying properties worsens. It was found that the worse of the rectifying property of the surface barrier structures is not due to the presence of compensating impurities, but depends only on the resistance of the base area. In the Schottky barrier structures based on n - Si with resistivities ~104 and 105 Ohm·cm the potential barrier is almost not formed. For the first time it was found that in structures with Schottky barrier under all-round hydrostatic pressure there is high strain sensitivity due to redistributions of electric voltage between the contact and the base area.
Study of the dependence of light ion sputtering yields of carbon-modified surface titanium layers on their thickness
Authors: Manukhin V V
Published: December 2022

A theoretical sputtering model based on two mechanisms is used in this work to investigate the dependence of light ion sputtering yields of carbon-modified surface titanium layers on their thickness. The model used allows not only to correctly describe the nonlinear dependence of the sputtering yields on the layer thickness, but also to analyze the resulting dependencies. Calculations of the total sputtering yields of helium and hydrogen ions of surface layers of titanium modified with carbon are given in comparison with the results of computer simulations.
Structure and thermal properties of chitin and chitosan from various sources
Authors: Ashurov N Sh , Abdurazakov M , Yugay S M , Atakhanov A A , Gulamjanov Kh A , Turaev J I , Akhymbetova G D , Rashidova S Sh
Published: December 2022

The structural and thermal properties of chitin and chitosan isolated from different sources (Artemia sp.cysts (from the Aral Sea) and Silkworm pupae (Bombyx mori)) were studied by using FTIR, XRD, and DSC. It is shown, that the chitin and chitosan samples from different sources have a similar structure, however, depending on the sources differ in the ratio of the phase composition. Two types of crystalline modification of the structure (α-and β-modifications) are observed for chitin isolated from Artemia sp.cysts. The chitin isolated from Bombyx mori has three polymorphs (α-, β-and γ-modifications) with orthorhombic, monoclinic and triclinic syngonies. The thermal stability of chitin and chitosan samples was also depended on sources.
Synthesis of powder functional composite materials containing g-C3N4, β-Si3N4 and Si2N2O phases
Authors: Zherebtcov I S , Osadchy A V , Savin V V , Savina L A , Chaika V A
Published: December 2022

The article discusses the technology of alloying carbon material with Taunite-M nitrogen and silicon, which combines mechanochemical synthesis in a spherical planetary mill and multistage heat treatment up to 1100°C. The aim of the work is to obtain a new material based on nanostructured carbon raw materials with improved physical and chemical properties as a result of the formation of new phases due to the introduction of silicon and melamine into the initial charge as a source of nitrogen. The phase composition of the obtained samples was studied by X-ray diffractometry, the porosity and distribution of chemical elements in the samples of the obtained material were evaluated using X-ray tomography and scanning electron microscopy. Based on the results obtained, conclusions are formulated about the formation of phases of graphite-like carbonitride, nitride and oxynitride of silicon in a thermally stable nanocarbon material.
Exhaled air Raman spectroscopy for Helicobacter pylori diagnostics
Authors: Popov E E , Polischuk A V , Vitkin V V
Published: December 2022

The possibility using Raman spectroscopy in the analysis of samples for the urease breath test to diagnose the presence of the bacterium Helicobacter pylori has been demonstrated. The Raman scattering spectra of the air exhaled by a person were obtained, the volume fractions of 12CO2 and 13CO2 in exhalation samples were determined.
New trends in the heat generators development with contact heating
Authors: Stoyanov Nicolay , Khashchenko Andrey , Smirnova Alla , Abornev Denis , Taran Sergey , Grinchenko Vitaly
Published: December 2022

The research relevance is conditioned by decrease in installations efficiency and high fuel consumption due to scale formation on heat-exchange surfaces, and conditioned by transition to ecologically clean, resource-saving power engineering and increase in hydrocarbon raw materials extraction efficiency. In this connection, this article aims at contact type heat generators application disclosing possibilities. The main approach to the study of this problem is the heat-transfer agent contact heating application. This article materials practical value is for complex heat supply systems engineers and designers.
Toroidal anapole with point magnetic dipoles
Authors: Borovkov Dmitrii , Valero Adrià Canós
Published: December 2022

The role of multipolar expansion of the localized current is significant in a broad range of disciplines in the physics of nowadays. It is actively used in such problems as the design of nanoantennas in photonics or the description of exotic states of matter. The toroidal multipoles are the third group of multipoles which complements the electric and magnetic multipolar families. The investigation of toroidal multipoles is important because of their role in the formation of so-called anapole states, non-radiating sources. The further study showed that there are also exist the higher-order toroidal dipoles or mean-square radii, which are equivalent. Here we suggest the structure which consists of point magnetic dipoles and supports the toroidal anapole state, which is obtained with the destructive interference of electric toroidal dipole with the first mean-square radius of the electric toroidal dipole. We also present an analytical condition for toroidal anapole with this system of point magnetic dipoles placed in two circles.
Practical realization and design of three-cascade prism mass analyzer for isotopic analysis of H-He mixtures using MS-platform technology
Authors: Gromov I A , Gall L N , Sachenko V D , Gall N R , Rajabov Sh U
Published: December 2022

The paper presents the construction of a mass analyzer for the analysis of hydrogen-helium mixtures based on a magnetic prism using a three-stage circuit that includes two cylindrical capacitors. The choice of an ion-optical scheme that provides a high resolution of 3300, which is necessary for the separation of all nuclides formed during the analysis of hydrogen-helium mixtures, is justified. It is shown that the innovative «MS-Platform» technology makes it possible to ensure high assembly accuracy of the elements of the prism mass analyzer ion-optical circuit, which is necessary to realize all the advantages of a prism mass spectrometer compared to sector ones.
Methodology for accelerated testing of fiber-optic sensors of heterogeneous physical quantities using the principle of prediction
Authors: Badeeva Elena , Murashkina Tatiana , Gaivoronskaya Tatiana , Polyakova Ekaterina , Motin Andrei , Kukushkin Alexey , Plotnikova Ekaterina , Olenskaya Alexandra , Arutyunov Armenak
Published: December 2022

The technique of accelerated tests of fiber-optic information-measuring systems, combining fiber-optic sensors of heterogeneous physical values, providing confirmation of technical and operational characteristics of fiber-optic information-measuring systems by applying the principles of acceleration, prediction of behavior of parameters-criteria of validity and distribution of test results of a test sample fiber-optic sensors, as well as the most technically perfected fiber-optic sensors of one physical value into a number of fiber-optic sensors of heterogeneous physical values unified by design and technological solution, which significantly reduces the time and material costs of conducting tests and obtaining their results.
Research and application of BaYF5 optical films in the range of 1.3-27 microns
Authors: Kotlikov E N , Andreev V M , Lavrovskaya N P , Tereshchenko G V
Published: December 2022

The determination of optical coefficients of absorbing coatings in the far infrared spectrum on silicon substrates is considered in this paper. To find them, a technique is used based on taking into account correction associated with absorption spectra. Correction of the spectra is carried out by exploitation models of the absorbing film. Optical coefficients of BaYF5 films in the spectrum region of 1.3-27 microns were obtained. On their basis, a band-pass metal-dielectric filter was synthesized for a wavelength 5 micron.
Application of the laws to compose fractal computation algorithms when modeling and analyzing their growth
Authors: Pylkin A N , Maikov K A , Kuzmenko S N , Teplov A A , Bubnov S A
Published: December 2022

Generalized analysis of the methods to construct fractals let to find algebraic patterns of fractal algorithm, fractal operators fi formalizing basic operations to construct the fractal structures of a specific type being the major concept. The fi are introduced with multiplication and addition operations together with the concepts of singular, zero and inverse operator that allow defining periodic and quasi-periodic fractal structures. An endless fractal length - basic operator which can give a possibility to obtain a limit fractal synthesis idea as a structure without self-similarity but with a regularly decreasing scale. The connection between fractal growth computations and widely examples of application in the nature is considered. Methods to analyze growth processes are offered, their basic characteristics are shown. The mathematical description of the fractal growth characteristics and their dependence on specifically defined parameters of algorithm are given. The analysis of fractal point growth trajectory is made. The algorithms applied and the methods to analyze growth processes are shown to be modernized and adapted for wide spectrum of tasks.
A software-based method for energy losses decreasing in cascaded buck + boost DC-DC converter
Authors: Nepomnyaschiy O V , Krasnobaev Yu V , Sazonov I E , Yablonskiy A P
Published: December 2022

A MOSFETs switching times calculation method for the known modulation strategy for bidirectional buck + boost DC-DC converter is presented. A former low-loss, constant-frequency modulation strategy based on a negative inductor offset current takes place at the beginning of each conversion period which provides the ability to turn on converter’s MOSFET switches under zero-voltage and zero current switching (ZVS/ZCS) condition. Time interval between switching times of half-bridge MOSFETs is needed to provide the ability to turn on the MOSFET under ZVS/ZCS due to its antiparallel diode takes over an inductor current. Described method based on a switching delay time estimation for the worst case of converter’s circuit components spread which allows to calculate proper MOSFETs switching times by Digital Control Unit (DCU). The article describes in detail the switching of the input half-bridge MOSFETs at first switching time. The clarified offset current calculation method, based on an estimated switching delay and converter’s input voltage is presented.
Decoding of the turbo code created on the basis of the block code using the syndrome grid
Authors: Sidorenko A A
Published: December 2022

Turbo codes came closest to the Shannon limit. They can be built on the basis of both block and convolutional codes. When decoding a block code using a syndrome lattice, it is possible to use well-studied algorithms for decoding convolutional codes with soft input and soft output. This publication demonstrates the application of the maximum a posteriori information decoding algorithm. The process of decoding a code sequence of a turbo code generated by an encoder consisting of two encoders of a block code and an interleaving device, in the presence of three errors in the received code word, is considered in detail.
Development of a gesture-based system of interaction with the interface of adaptive information systems
Authors: Patutin Kirill , Surkova Ekaterina , Sokolinskaya Olga , Shilcin Maxim , Prokudina Nina
Published: December 2022

The implementation of gesture control is an actual direction in the field of organizing interaction with adaptive information systems. This study considers the development of a neural network-based gesture control system for hand recognition and gesture classification. When implementing such systems, it is necessary to ensure the maximum accuracy of gesture recognition, as well as high performance (video stream processing speed). At the first stage of the study, the task of optimizing gesture control system was posed, including analysis of the information processing algorithms used for optimization according to the criteria of classification accuracy and performance. In the course of solving the optimization problem, the structure and parameters of the neural network were determined that provide the best accuracy indicators, and the necessary changes were made in the software of the gesture control system to achieve the required level of performance. The developed software for the gestural interaction system was tested when integrating with the interface of adaptive information systems implemented on the basis of the Unity game engine. The results obtained can be used in the implementation of interfaces for interaction with virtual reality with a high level of immersion.
Building a sequential turbo code with additional encoding of information bits
Authors: Sidorenko A A
Published: December 2022

Turbo codes have the best correction ability in a data transmission channel with a high bit error rate, and are used in a variety of data transmission systems. This publication describes the possibility of improving the corrective ability of the sequential turbo code by additional encoding of information bits. A method for introducing the reliability coefficients of the decoded bits of the received code word of the turbo code is considered. A practical example shows the effectiveness of the proposed methods. The tasks of further research in this area are described.
Human motion capture algorithm for creating digital shadows of the movement process
Authors: Obukhov Artem D , Volkov Andrey A , Vekhteva Nadezhda A , Teselkin Daniil V , Arkhipov Alexey E
Published: December 2022

The improvement of virtual reality systems declares new requirements for the user immersion quality. To improve the immersiveness of the interaction process with virtual space, it is necessary to provide a realistic representation of a person in it, as well as the processes of his movement and interaction with virtual objects. In this work, the issue of using motion capture technologies to create a realistic avatar (digital shadow) and visualization of the movement process is considered. An algorithm for capturing human movements based on synchronization of various hardware solutions has been developed to create a digital shadow of the human movement process. The algorithm can be used to match the user with his virtual copy in virtual reality systems. The scientific novelty of the method lies in taking into account the position, direction and speed of a person’s movement, synchronization of the motion capture hardware tools used to create digital shadows of the person’s movement process.
Mathematical model of the digital shadow of the human movement process
Authors: Obukhov Artem D , Patutin Kirill I , Volkov Andrey A , Nazarova Aleksandra O , Dedov Denis L
Published: December 2022

The process of forming a digital shadow of the human movement process is considered, which can be used in virtual reality systems, musculoskeletal rehabilitation, and other human-machine systems based on the analysis of the user’s movement. The most important step in creating the digital shadow is its formalization in the form of a mathematical model. At present, the issue of the formalization of digital shadows of various objects and processes has not been fully developed. The article discusses the development of the mathematical model of the digital shadow of the movement process, the novelty of which lies in combining information from four sources (three different motion capture systems and a complex of medical sensors to assess the physical condition of a person), as well as their synchronization and filtering. The obtained theoretical results will be used as a basis for software abstraction of the digital shadow in information systems to solve the problems of testing, simulating a person and modeling his reaction by summarizing the collected data arrays about his movement.
Mathematical model of the process of mixing and separation in a microfluid channel with five outlets
Authors: Kurbangaleev A A , Tazyukov F H , Gerasimov A V , Karibullina F R
Published: December 2022

The article presents the results of mathematical modeling in a two-dimensional formulation of the mixing process by mutual diffusion and separation of flows of Newtonian fluids in a microfluidic mixing channel with five outlets. Branches are used to separate flows into fractions with a given concentration of one of the components in the mixture. The diffusion process occurs in a laminar flow regime, without chemical and thermal interaction. The mixture flow model was set up in a two-dimensional formulation. One component of the mixture flows through the main channel 1 mm wide, then at a distance of 5 mm from the entry point to the channel perpendicular to it, there are two more entrances also 1 mm wide, through which the second component is fed. At the outlet, there are five taps with dimensions of 0.2 mm to take the mixture of the desired concentration. Four outlets for the intake of the mixture are located opposite each other in pairs. Liquids with the physical characteristics of water and ethyl alcohol were taken as miscible components. The problem was solved using the ANSYS-Fluent software package.
Efficiency rectification of predictive machine learning models by data centric optimization
Authors: Bekeneva Ya A , Sultan S
Published: December 2022

There are two ways to optimize the performance of machine learning models, one is model centric, and another is data centric. Model centric approaches sometimes cannot yield expected results, so researchers and developers are now focusing on data centric optimization. Main steps of data centric approaches are – noise detection and correction, effective feature selection, feature transformation and data augmentation in case of limited datasets. Be it image, audio, text or numerical data, the mentioned approaches are always beneficial irrespective of model architecture. This paper is devoted to developing new preprocessing techniques for numerical data. The developed algorithm is tested with different artificial and real datasets for linear regression, k-means clustering, SVM classifier and deep learning networks. The algorithm is easy to implement and computationally less expensive. Experimental results show that proposed methods work well to improve model efficiency.
Forecasting the environmental situation at the purification plants of the enterprise based on fuzzy logic
Authors: Ivashchuk O D , Nesterova E V , Igrunova S V , Kaliuzhnaya E V , Udovenko I V
Published: December 2022

The study set the goal of improving the efficiency of various technological schemes of purification plants of the enterprise through the development of an expert system based on fuzzy logic methods and the formation of practical recommendations for improving the characteristics of wastewater from the operation of schemes of purification plants.
Model of operation of computer measuring system
Authors: Ershov D S , Malahov A V , Levina T A , Khayrullin R Z
Published: December 2022

The implementation of the concepts of a smart home - smart city implies a high level of automation using control and measuring devices and equipment, as well as computer and informational technologies. One of the effective trends of automation is the widespread use of computer measuring systems Article presents the model of operation of a computer measuring system with digital data processing is proposed. The presented model is based on the semi-Markov model of operation of an analog-to-digital converter, on the semi-Markov model of an embedded personal computer, on the analytical formula for calculating the availability factor of computer measuring system. The analytical expression for the availability factor of a computer measuring system includes both the technical and operational characteristics of the computer, as well as the metrological and technical characteristics of the analog-to-digital converter. The specified expression allows to find the optimal value of calibration and verification interval. Determination of the optimal calibration interval required to control the metrological characteristics during long-term operation of the computer measuring system. The developed model can be used to set requirements for the metrological support of instruments and de-vices used in the framework of the automation trend in the sphere of housing and communal services.
Vector fields and differential equations
Authors: Ya Narmanov A , Rajabov E O
Published: December 2022

The geometry of orbits of families of smooth vector fields is an important object of mathematics due to its importance in applications, in the theory of dynamic systems and in the foliation theory. The paper devoted to the applications of the geometry of orbits of vector fields in four dimensional Euclidean space in theory of differential equations. It is shown that orbits generate singular foliation ever regular leaf of which is a surface of negative Gauss curvature and zero normal torsion. In addition, the invariant functions of the considered vector fields are used to find solutions of the two-dimensional heat equation that are invariant under the groups of transformations generated by these vector fields. In this paper smoothness is smoothness of the class C
∞.
Extraction of individual gait features in mobile phone accelerometer
Authors: Dorofeev N V , Grecheneva A V
Published: December 2022

An algorithm for extracting individual signs of a person’s gait according to the data of a mobile phone accelerometer is considered. The developed algorithm includes the stage of data segmentation, correlation selection of motion patterns, and data clustering procedures. By selecting noisy segments, the quality of data clustering and the extraction of individual features is improved. The results of the algorithm work allow us to refine the existing models of changes in human motor behavior in personalized medicine and security systems. The article also discusses the features of data segmentation and the influence of external factors on the measurement results.
Recognition of the emotional state of energy facilities operators based on artificial immune systems
Authors: Nuriakhmetov A I , Bogdanova D R , Yusupova N I
Published: December 2022

This research paper presents results on the construction of a system for recognizing emotional state of energy facilities operators by the expression of their faces in the images. The model uses one of the algorithms of artificial immune systems as a classifier. An artificial immune system is a concept that contains methods and algorithms that try to apply the basic mechanisms of biological immune system to solve various practical problems. In accordance with the main aim of the research, the article deals with existing concepts of emotion classification as well as current methods for recognizing emotions from facial expressions in images. Also, a brief review of the literature is given in accordance with the questions posed. The proposed model uses a feature extraction approach based on marking the human face with 68 points, followed by extraction of their coordinates. For the obtained coordinates, a new special technique for their processing for subsequent classification is proposed. The built model is able to classify the 7 basic Ekman emotions both on images and in the video stream, with an accuracy of about 80%.
Formalization of the problems of synthesizing adaptive control systems with reference models
Authors: Igamberdiev X Z , Botirov T V , Latipov Sh B
Published: December 2022

The problem of synthesizing adaptive control systems for continuous technological objects is an urgent scientific problem, the solution of which has the great theoretical and applied significance. This article covers the formalization of the problem of synthesizing adaptive control of complex objects based on reference models. The direct approach is connected with the use of a standard, under which the running of the entire system or its part is adjusted. The correction is performed based on minimizing the quality functional from the mismatch between the standard and the real system, as well as the ways of constructing regulators based on the concepts of the theory of direct adaptive systems are considered.
Decoding of stimuli time series by neural activity patterns of recurrent neural network
Authors: Bartsev S I , Markova G M
Published: December 2022

The study is concerned with question whether it is possible to identify the specific sequence of input stimuli received by artificial neural network using its neural activity pattern. We used neural activity of simple recurrent neural network in course of “Even-Odd” game simulation. For identification of input sequences we applied the method of neural network-based decoding. Multilayer decoding neural network is required for this task. The accuracy of decoding appears up to 80%. Based on the results: 1) residual excitation levels of recurrent network’s neurons are important for stimuli time series processing, 2) trajectories of neural activity of recurrent networks while receiving a specific input stimuli sequence are complex cycles, we claim the presence of neural activity attractors even in extremely simple neural networks. This result suggests the fundamental role of attractor dynamics in reflexive processes.
Development of pipeline feature engineering for building an AutoML service
Authors: Parfenov D , Bolodurina I , Grishina L , Zhigalov A , Legashev L
Published: December 2022

The large–scale implementation of artificial intelligence approaches in applied fields has a number of limitations, one of which is the availability of research competencies, knowledge of data analysis methods, mathematical statistics and machine learning. Automatic machine learning is designed to simplify the methodology of ML application development. Within the framework of this study, a new approach to the construction of pipeline feature engineering for AutoML service is presented, based on the sequential expansion of the feature space and the use of autoencoders to reduce the dimension of input features and reconstruct the final output features. The results of the presented approach are shown by the example of VANET network traffic data when solving the problem of classifying attacks on nodes. The data set was obtained as a result of simulating the real traffic of a certain segment of the VANET network in the OMNET++ environment and subsequent aggregation of data on network flows by means of CICFlowmeter-V4.0. Experiments have shown that machine learning models on the source data have an accuracy of 2% lower on average, which indicates the effectiveness of using the proposed Feature Engineering approach. The highest classification accuracy was demonstrated by Pipeline using the Multi–layered Model autoencoder and the XGBoost classification model – 91.2%. Thus, the presented Feature Engineering approach can be used to build the most effective feature space and improve the quality of machine learning models.
On the use of the skin effect for eddy-current control of cylindrical metal products
Authors: Vornacheva I V , Pankov D N , Malikov V N , Scherbakov A P , Kuzmin O V , Voinash S A , Yu Remshev E
Published: December 2022

In this paper, the fundamentals of the theory of the skin effect as applied to long cylindrical ferromagnetic conductors when exposed to a high-frequency electromagnetic field are considered. The results of this study can be used to process experimental data obtained, as a result, of studying the fatigue properties of ferromagnets.
Assessment of the load-bearing capacity of materials and structures using a finite element model
Authors: Sazonova S A , Zyazina T V , Smetankina G I , Barsukov A I , Akamsina N V
Published: December 2022

The current technical condition of a multi-storey frame building structures is studied. The survey is carried out for individual structural elements of the object, which makes it possible to determine the actual technical condition of the building and its constituent elements. Additional damage and defects appeared at the object under study due to the forced break in construction. Verification calculations of the non-existent capacity of structures were performed based on the results of the technical condition monitoring. The existing real operational loads and impacts were taken into account in the calculations for the actual design schemes. The results of field studies were processed to develop a reconstruction project for a frame multi-storey building. Quantitative estimates of the actual quality indicators of load-bearing building structures were used. A computer-based verification calculation based on the application of a finite element model was performed for the construction of a cinema hall located in the frame building under study. Plots of internal forces in structures are obtained. It is concluded that the object under study is in a working technical condition.
Analysis of subharmonic oscillations in three-phase Ferroresonant circuits with bias
Authors: Tovbaev A N , Ibadullayev M , Norboyev S I
Published: December 2022

In the theory of nonlinear electrical circuits, the analysis of physical processes occurring in three-phase Ferroresonant circuits during excitation of subharmonic oscillations (SHO) of the second order is of particular importance in the design and creation of various converter devices. From the point of view of creating multi-phase secondary power sources (phase-discrete devices, frequency dividers, switching elements, automation and relay protection devices, etc.), the study of second-order SHO excitation in three-phase Ferro resonant circuits with bias is of greatest interest. The article deals with the excitation of second-order subharmonic oscillations in three-phase self-oscillatory circuits with common magnetic circuits with a bias winding. Shortened equations are derived using the averaging method with appropriate phases. From the condition for the existence of a periodic solution, the phase and amplitude relationships of the excited oscillations are determined, which are different from three-phase circuits with a separate ferromagnetic element. In the steady state, the conditions of excitation, the region of existence are determined depending on the parameters of the circuit, the bias current and the applied action. The stability of the solution of the original system of nonlinear differential equations of the second order is also studied by analyzing the roots of the characteristic equation by a qualitative method. Numerical realization of the initial considered system of equations described, self-oscillatory processes is given.
Carboxyl-functionalized aluminum oxide nanofibers for powder coatings
Authors: Simunin M M , Yu Chirkov D , Samoilo A S , Fadeev Yu V , Voronin A S
Published: December 2022

The paper considers the production and use of alumina nanofibrous additives in nanocomposite powder paints. The main component of powder paints are polyester resins with a large number of free carboxyl groups, which are cross-linked with special hardening additives. The introduction of additives into the resin is most effective when their surface is matched in terms of physicochemical properties with the resin material. In order to increase the affinity of the alumina nanofibers with the powder paint matrix, the amphoteric surface of the nanofibers must become acidic. The paper describes a method for the functionalization of alumina nanofibers by successive silanization with aminopropyltriethoxysilane and priming with oxalic acid. The paper described about the compounding of alumina nanofibers leads to increase of the coating strength and an increase in its elasticity. Priming alumina nanofibers by aminopropyltriethoxysilane in toluene leads to its functionalization sufficient to homogenize the nanofibers in the polymer media of the powder paint and improve its product properties. The formation of an amide bond after the final stage of priming of alumina nanofibers in oxalic acid by indirectly method is shown.
Calculation of gasket vibrations under a steady operating mode of the linter machine
Authors: Mukhammadiev D M , Kh Ibragimov F , Kh Abzoirov O
Published: December 2022

The article presents the results of calculating the saw gasket vibrations in the steady state operation of the linter machine. It was established that the stable position of the equilibrium of saw gasket vibrations is achieved in the steady state operation of the linter machines. To determine the vibrations of the saw gasket in the steady state operation of the linter machine, calculations were conducted with expansion into a series of kinetic and potential energies. As a result of the calculations, the frequency and period of oscillations of the saw gasket were determined under the steady-state operation of the linter machine with aluminum alloy and steel materials. Calculations have shown that an increase in the frequency of vibrations is 2.88 times for steel gaskets and a decrease in the period of vibrations is 34.7% relative to the aluminum alloy. The results of calculations of the vibrations of the steel saw gasket in the steady state operation of the linter machine showed the resistance to vibrations and the expediency of their use in the linter machine when assembling the saw cylinders.
Computational approach to estimation the transverse Stability of multi-section chassis of extreme cross-country vehicles
Authors: Yu Dobretsov R , Shen Yunfeng , Vagizov T N , Timokhova O M , Karnaukhov A I , Ivanov A A , Sokolova V A
Published: December 2022

Multi-section chassis have a great potential for geometric and fifth wheel cross-country ability. An example is a model of a six-wheeled all-wheel drive planetary rover designed at VNIITM to study the mobility of the mobile laboratory of the Mars-94/96 project. The concept of extreme cross-country chassis involves the use of three articulated sections with a wheel mover with a removable track or a permanent track module. The rotation is carried out by changing the relative position of the sections in the plan. The article proposes mathematical models that make it possible to calculate by calculation the critical speeds and radii, according to the transverse overturning and skidding, which limit the possibility of a multi-section tracked vehicle when turning. Further development of the model implies taking into account an arbitrary scheme of external forces (including the longitudinal component of the inertia force) and caterpillar sliding, and, as a result, the transition to an iterative process in the calculations. To check the models, a calculation was made for a mass-produced two-section military transport vehicle. The prospect of using the proposed models is a preliminary assessment of the transverse stability of a three-section chassis of extreme cross-country ability.
On the global model of the ionospheric equivalent slab thickness
Authors: Maltseva O , Nikitenko T , Kharakhashyan A
Published: December 2022

The equivalent slab thickness τ of the ionosphere links two of its parameters: the critical frequency foF2 and the total electron content TEC and, as a consequence, allows the determination of foF2 using TEC. Interest in the parameter τ has recently increased, as evidenced by a publication in Space Science Reviews 2022, 218:37, 1-65, which provides a historical overview of τ research, presents features of τ behavior in different regions of the globe under different solar activity conditions, and indicates directions for further research. This led to the following objectives for this paper: (1) estimating the correlation coefficient between foF2 and TEC, (2) testing a unique global model τ(NSTM) - the Neustrelitz equivalent Slab Thickness Model, (3) estimating the relation between τ and the Dst index. Using data from 78 stations divided into several longitude zones, it is shown for April 2022: (1) a high correlation between foF2 and TEC on a global scale is confirmed, but there is a large dependence on data quality, (2) each longitude zone has stations for which τ(NSTM) gives good agreement with experimental values and can be used in applications, (3) the correlation coefficient ρ(τ-Dst) is found to depend on longitude, which may have a physical nature.
Study of the distribution morphology of alumina nanofibers in polyester resins
Authors: Simunin M M , Chirkov D Yu , Zaloga A N , Fadeev Yu V , Kuular A A
Published: December 2022

In this paper, the morphology of nanocomposite polyester resins has been studied. The basis was polyester resin NH6586 produced by Kinte. Aluminum oxide nanofibers were introduced into the resin, which are single crystals or chains of single crystals with the γ- Al2O3 structure with a diameter of 5 to 15 nm and up to 1 mm in length. The additive was introduced into the resin by the industry standard twin screw extrusion method. At the same time, the influence on the uniformity of distribution of the addition of mineral filler - submicron particles of titanium dioxide - was studied. It has been shown that conventional methods of mixing the additive do not allow the nanofibers to be completely distributed. In such cases, they are distributed in the form of microbundles. The addition of mineralfiller to the polyester resin improves the distribution of the alumina nanofibers so that no bundle inclusions are observed in the resin cleavage. Thus, it can be concluded that mineral additives of isometric particles are an effective homogenizer of aluminum oxide nanofibers in polymeric materials.
Short-term reliability prediction for highly noisy radio engineering systems
Authors: Vasilkov Yu V , Sovetov V A , Kessidi K A , Yaskin E A
Published: December 2022

Evaluating the effectiveness of complex systems is becoming difficult due to the increasing complexity of such systems, as well as the high significance of predictions of their technical condition. Therefore, the experts pay considerable attention to them. This is largely due to the large number of components (blocks, nodes, elements) of such systems and the variety of technical and information links between them. All this causes an avalanche-like increase in the number of studied properties that affect the reliability of the entire system. The paper considers the problem of identifying linear and harmonic components in a highly noisy time series based on information obtained during its operation. It shows how to separate various components (linear, harmonic) from the general time series. The work is aimed at short-term prediction of the functioning reliability of radio engineering devices for solving certain fast operations over a given time interval. After the deterministic components are isolated from the time series, the error of its short-term prediction is estimated based on the remaining random centered component by its variance.
Signal-to-noise ratio measurement for the signals with constant amplitude
Authors: Chernoyarov Oleg , Glushkov Alexey , Litvinenko Vladimir , Litvinenko Yuliya , Pergamenshchikov Serguei
Published: December 2022

A digital meter measuring the signal-to-noise ratio in the channel for transmitting discrete information with a constant amplitude of symbols that are the phase or frequency shift keyed signals is proposed. The desired value of the signal-to-noise ratio is determined based on the number of exceedings of the threshold level by the modulus of the logarithm of the ratio of the amplitudes of the received and previous symbols in the sample of a specified size, while the meter itself is invariant to the absolute levels of the signal and noise. It is shown that in the channel with Gaussian noise, this number depends only on the desired signal-to-noise ratio. The necessary calculation relations are successfully obtained; it is also established that the Gaussian approximation of the symbol amplitude probability density is valid. Statistical simulation of the meter operation has been carried out for receiving binary phase shift keyed signals. It is proven that the given theoretical meter characteristics are in satisfactory agreement with the corresponding experimental data and the small measurement error is provided within a wide range of signal-to-noise ratio values.
Comparison of theoretical modeling of natural frequencies of a pipe section with data obtained empirically
Authors: Maykov O A , Kokhonkova E A
Published: December 2022

The article explores the issue of modeling a pipeline section, to determine the possibility of diagnosing the state of the pipeline walls, by analyzing the frequencies of natural vibrations. This method is considered as a possible alternative to in-line diagnostics of main pipelines. Frequency analysis allows to determine the defective state of the walls by reading vibrations with a vibration sensor located on the body of the pipeline.
Electron-beam additive manufacture to produced ER321/CuA19Mn2: microstructure and mechanical properties
Authors: Panfilov A O , Zykova A P , Chumaevskii A V , Vorontsov A V , Yu Nikonov S , Shmakov V
Published: December 2022

Used electron-beam additive manufacture with two wire filaments simultaneously produced composite 321SS/CuA19Mn2 with 50:50 components ratio. Investigated of microstructure and mechanical properties of composite 321SS/CuA19Mn2 and compared with properties of stainless steel with aluminum bronze produced by electron beam additive manufacture. It was found that the formation of the composite 321SS/CuA19Mn2 leads suppresses of the residual β’-phase: diffusion of elements initiates phase transition from γ-Fe to α-Fe and leads to formed nanoparticles of κiv-phase in solid solution of α-Cu. Mechanical tensile tests and microhardness were showed composite 321SS/CuA19Mn2 have highest microhardness (∼3280 GPa) and highest tensile strength (830 MPa) as compared with steel and bronze produced by additive manufacture.
Setting the level of design inputs for the seismic stability structures
Authors: Uzdin A M , Ivanova T V , Sorokina G V , Lin Hong , Kurbanov Kh Kh , Nazarova Sh Sh
Published: December 2022

The paper deals with the task of setting the level of the design input for assessing the structure seismic resistance. An increase in the expected peak ground accelerations with the development of the earthquake engineering from 1 m/s2 to 7 m/s2 is noted. The absence of a correlation between the peak ground accelerations and the seismic action intensity, as well as the dependence of the peak ground accelerations on the action spectral composition, is explained. A method of determining the ground design acceleration using the standard seismic scale in force in Russia is shown. The illogicality of setting the design input according to of the Guidelines “Earthquake Engineering” in force in Russia is shown and ways of correcting the current situation are indicated. It is noted that to solve the problem of setting the design input, no seismic zoning maps are required. Information on seismic hazard can be represented by a single number characterizing the relationship between the intensity and repeatability of the action on the construction site. The relationship between the design accelerations stated in the «Earthquake Engineering» Guidelines and the peak ground accelerations in the «Seismic Intensity Scale» State Standard is explained. The approach described in the paper is the basis for input setting for performance-based designing.
Smooth-polylines vs. polynomials in balanced identification technology: solving inverse problems of thermal conductivity
Authors: Sokolov A V , Voloshinov V V
Published: December 2022

Various parameters’ identification problems of one-dimensional nonlinear heat equation are considered. Their numerical study was carried out on the basis of balanced identification technology, which provides a compromise between the simplicity of the model (the curvature of the functions) and the proximity to experimental data. The problem of identifying functions whose arguments are model variables is considered. When approximating such a function, we had to use a polynomial function – the use of polylines (polygonal lines) in this case (superposition of functions) leads to nonsmooth mathematical programming problems (with discontinuous derivatives) with the solution not supported by standard solvers. An investigation of the use of special smooth approximations of polygonal curves (smooth-polylines) is presented.
Investigation Ne ions scattering from the stepped InP(001)<ī10> surface
Authors: Kutliev U O , Otabaev M U , Karimov M K
Published: December 2022

We present in this paper possibility of using glancing incidence ions scattering process for the determination of surface atomic step. We study the grazing scattering of Ne+ stepped InP(001)<ī10> surface in small angle of incidence ions. Additionally, we elaborate on the spectra of energy some intensive maximums formed by ions scattered from the monoatomic surface steps. Based on concrete examples, we also observe the effect of the atomic mass of the stepped atoms on the process of ion scattering. We study the trajectories of ions which scattered from stepped InP(001)<ī10> surface and found that the track of scattered ions have a zig-zag shape. An ion Ne trapped in a channel formed by an atomic step, after passing some distances, dechannels due to a hard collision of one of the atoms forming the basis of the channel. The physical settings of dechannelized Ne ions were analyzed and calculated, and this calculation makes it possible to understand the mechanism of ion dechanneling.