bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral analysis method of electrophysical non-destructive testing data
Authors: Surin V , Beketov V , Ghazal Ayman Abu , Alwaheba Anas 
Published: December 2021

Abstract
A computational method for spectral analysis of the electrophysical test results based on sequential mathematical algorithm transformations using a discrete linear response function has been developed. The procedure for constructing spectral functions has a certain order and is aimed at obtaining adequate results of the experimental sample approximation in the frequency domain. It is shown that use of the low-frequency FIR filter function as part of the convolution, together with the fast Fourier transform, gives accurate results for structural inhomogeneities localization in welded joints.
Numerical modelling of heat treatment of concrete of monolithic structures of buildings in winter conditions of construction
Authors: Petrov E , Korobkov S , Kuznetsov S 
Published: December 2021

Abstract
The paper presents the results of numerical modeling of heat treatment of concrete of a monolithic floor using a heating wire in winter conditions, depending on factors such as ambient temperature, wind speed, isothermal curing temperature, and others. The following parameters were taken as the main parameters for calculating the heat treatment of concrete: the geometric dimensions of the concreting area, the type and dimensions of the thermal insulation layer to ensure thermal protection of the monolithic structure during the heat treatment of concrete, the type and characteristics of transformers that provide the necessary power for preheating and heating concrete of monolithic floors, as well as the class of concrete, cement consumption and type of heating wire. As a result of calculations, the values of the required power for heating concrete of monolithic structures, the number of transformers, the voltage on the transformer for heating the concrete, as well as the duration of the periods of heating, isothermal curing and cooling during the heat treatment of concrete were obtained. As a result of the performed numerical experiments, the modes of heat treatment of a monolithic floor were deter-mined, which ensure the achievement of the required strength of concrete of monolithic structures. This type of heat treatment of concrete during winter periods has established itself as energy efficient and versatile, since heating wires can be used in structures of any type, configuration and reinforcement. With the correct use of heating wires, it is possible to obtain high-quality reinforced concrete structures erected at negative ambient temperatures.
Numerical simulation of electric heating of dispersed-reinforced concrete with steel fibers
Authors: Matus E , Soppa M 
Published: December 2021

Abstract
Solution to the problem of current density distribution in a fragment of a steel fiber concrete mixture is obtained, using the finite element method. It is shown that the fiber-concrete contact layer makes a significant contribution to the effective electrical conductivity of the mixture. More than 50% of the total current flows through the reinforcing fibers. The conductivity of the mixture increases in proportion to the reinforcement coefficient. It increases 2-3 times, depending on the choice of the contact properties, reinforcing 2% by volume layer. Experimental data that confirm the indicated dependence are presented. Also, a solution to the problem of heat distribution in a fragment of steel-fiber-concrete mixture in stationary and non-stationary modes of external heating and electrode heating was obtained. It is shown that the effective thermal conductivity coefficient increases in proportion to the reinforcement coefficient. A significant effect of the contact layer parameters on thermal conductivity is shown, comparison with experimental data. Significant heat release in the area of contact zone and in fiber leads to a temperature rise in these zones by 20-30 degrees in a stationary mode. The temperature distribution in fiber-reinforced concrete during induction heating is considered. In this case, it is necessary to significantly increase the frequency of the current used. The study results can be used, prescribing electric heating modes for products made of dispersion-reinforced concrete.
Calculation of the temperature fields spread at subzero temperature in a monolithic beam
Authors: Molodin V , Chirkunov Yu , Lazarev A , Gorshkova K , Gulenkova P 
Published: December 2021

Abstract
Monolithic construction in winter is faced with problems of concrete strength gain at subzero ambient temperatures. In order to ensure the necessary temperature conditions for hardening and hardening of concrete, various methods of heating structures are used. The relevance of this article is due to the climatic conditions of construction in most of the Russian territory and lack of a unified calculation method. The existing calculation methods are either easy to use, but give approximate answers, or exact solutions, but cumbersome and inconvenient in daily use. This paper presents group analysis method of differential equations used to predict temperature regimes for concreted structures. Solving the nonlinear differential equation of thermal conductivity by group analysis made it possible to derive, using nonlinear submodels, simple and convenient for practical application calculation formulas for modeling the temperature fields of heated structures. Experimental verification of the two proposed solutions of the nonlinear equation was carried out on the basis of the monolithic girder model, subjected to heat treatment at different powers.
Mathematical model for calculating the temperature field of a direct-flow drying drum
Authors: Mamatov A , Parpiev A , Shorakhmedova M 
Published: December 2021

Abstract
In this paper, one parabolic-type boundary value problem is solved for determining the temperature field of the raw cotton and air components in drum dryers. In the proposed model, convective heat transfer is used according to Newton’s law, the terms describing the evaporation of moisture from the components of raw cotton (seeds, fiber) and the influence of air velocity are taken into account. The resulting system of Galerkin’s differential equations is solved by the finite-difference method in time. It is shown that the approximate solution is estimated according to Galerkin in Sobolev space.The numerical results of the considered problem are obtained by the Bubnov–Galerkin method. A comparative analysis is carried out with experimental data. It is shown that the proposed mathematical model and its numerical algorithm adequately describe the drying process of raw cotton.
Assessment of the efficiency of the use of activating turbulent jets to eliminate the risk of the formation of unventilated zones in large premises
Authors: Grimitlin A M , Strongin A S 
Published: December 2021

Abstract
Strict requirements for microclimate parameters are imposed on food storage premises, which are equipped with artificial cooling systems. The experience of operating the refrigerated premises revealed the following disadvantages: uneven distribution and significant fluctuations in temperature and relative humidity; periodic precipitation of condensate in low-temperature sections. Elimination of the noted disadvantages is effectively achieved by using axial fans that form a swirling air stream that induces the ambient air. Swirling jets used to intensify the process of air circulation in a room in order to eliminate unventilated zones will be called activating jets. To assess the efficiency of the application of activating turbulent jets, an integral method based on the energy balance was used. Using the example of a representative object, it is shown that the distance of the effective application of an activating turbulent jet should be calculated taking into account the influence of environmental turbulence, which is determined by the amount of energy introduced and dissipated in the room.
Visualization of physical and mathematical models of thermodynamic processes of single-phase flows using MATLAB to diagnose the condition of external heat supply networks
Authors: Petrov A , Popov A 
Published: December 2021

Abstract
Nowadays, Russia has the longest heating network system in Europe (about 125 000 km in total). Given the constant growth in the volume of construction space, the length will constantly increase. Consequently, there is a request to increase the level of reliability of heat supply networks. It is possible to satisfy the request only by increasing the volume and quality of comprehensive diagnostics of heat supply networks with simultaneous reduction of time costs. This is possible only if a new generation of measurement and computing complex (MCC) is developed for the diagnosis of heat supply networks. The team of authors examines the features of the information environment in heat supply networks, separately noting the possibility of switching the flow from single-phase to multi-phase and back. The paper proposes to consider a solution to a problem that arises when trying to visualize physical and mathematical models of thermodynamic processes of single-phase flows using MATLAB. It consists in the fact that the desired physical and mathematical model should describe the thermodynamic processes of a single-phase flow, but taking into account that this flow moves in the external heat supply network. The possibility of using the MATLAB functional environment for developing a model based on visually oriented programming is considered in detail, which allows us to lay the foundations for further forecasting the development of the heat supply system.
Monitoring system for temperature and relative humidity of the experimental building
Authors: Kuzmenkov A A , Kuvshinov D A , Yu Buryachenko S , Kaychenov A V , Karachentseva I M , Voronin Z A 
Published: December 2021

Abstract
The article presents the results of the development and implementation of a monitoring system for temperature and relative humidity of an experimental wooden building. The developed monitoring system allows recording in real time the temperature and humidity of the internal microclimate, layers of enclosing structures and the external environment. The monitoring system is represented by two subsystems: measuring and indicative. The building has 25 measuring points in key parts of the building. Within the framework of scientific research, the system will make it possible to assess the parameters of the internal microclimate and the state of the building envelope in real operating conditions with changing environmental parameters.
The new drying technology of sea cucumber
Authors: Zhang M , Mamatov Sh , Yaping Sh , Jia A , Liu Ch 
Published: December 2021

Abstract
In this work, we studied the drying characteristics and the quality of sea cucumbers (Stichopus japonicus) that underwent preliminary processing using microwaves during freeze drying. The qualitative parameters of the samples (FD) are compared. The results of shortening the drying period using microwave pre-treatment during drying are analyzed. Experimental data were also obtained and the rehydration process and the chemical composition (protein, carbohydrates) of the dried sample were compared.
Gas flow modeling in wells
Authors: Khudjaev M , Rakhimov A 
Published: December 2021

Abstract
The topic of research is gas flow modeling in wells. The subject of the study is to determine the dynamic parameters of gas in a gas well, taking into account changes in the ambient temperature and gravity. Mathematical and numerical modeling of gas flow in a gas well is performed; a numerical algorithm to determine gas pressure in a gas well is built. This algorithm allows studying the state of production and injection wells with varying conditions at the wellhead and at the lower end of the well. Research methods are based on the energy equations of the transported gas; the mass conservation equation, which are the basic equations of gas flow; the methods of numerical and mathematical modeling. In the article, numerical and mathematical models of gas flow in a gas well are obtained, taking into account changes in the ambient temperature and gravity. A numerical algorithm and a program were built to determine the gas-dynamic characteristics of wells. The computational process was based on the “cycle in cycle” principle. Provisions were made to study the state of production and injection wells with varying conditions at the wellhead and at the bottom end of the well.
Precision of determination of thawing depth of the frozen rocks
Authors: Galkin A , Pankov V 
Published: December 2021

Abstract
An important quantity determining the choice of technical solutions in design of both surface and underground structures in the permafrost area is the thawing depth of the rocks. To obtain simple analytical relations to determine the thawing depth over time, a simple assumption is used: that the initial temperature of the rocks is equal to the melting temperature of ice. The aim of the present work was the assessment of impact of this assumption on the forecast precision. For a quantitative assessment, a simple typical formula recommended by construction norms was used. Functional dependence of the density of the rocks and their heat capacity on the fraction of ice content was considered in the formulas. A rock consisting of a combination of quartz sand and ice was used as an example.Multiple variant calculations were done according to the formulas and their results presented in the form of charts. It was shown that the relative error in determination of thawing depth depends solely on the Stefan criterion and is independent of the thawing duration, thermal conductivity coefficient of the thawing rocks and the air temperature during the thawing. A relation was obtained which allows to quickly assess at which initial values (temperature and ice content of the frozen rocks) it is possible to use the formulas obtained from the simplified calculation models with the assumption that the temperature of the rocks is equal to the melting temperature of ice.
Modern laser-technologies and nanotechnologies - next-generation on new physical principles
Authors: Arakelian S M , Evstyunin G A , Zdanov A V , Abrakhin S I 
Published: December 2021

Abstract
In the paper we discuss new tendencies and trends in laser/nanotechnologies based on topological material-science with spatial structures of necessary types induced by laser radiation on solid surface. Review of the current state of research on this issue, main directions and scientific advantages are presented. In our study we used originally manufactured the multibeam laser-technological automated complex for thermal hardening of the surface of different products with variable elemental composition. The database for several functional characteristics, varied under processing by laser radiation the surface of materials, is given.
Mechanical and tribological characteristics of laser-deposited nickel-containing powders on chromium steels
Authors: Dovbysh N S , Zhdanov A V 
Published: December 2021

Abstract
This paper presents the results of a study of various processing modes during the laser surfacing process. Various grades of steel were used as samples, and the resulting coatings were based on two grades of powders. The microhardness values were obtained both for the main steel material and for the coatings obtained on the samples. The values of the friction coefficients of the coatings are obtained, on the basis of which the graphs of standard deviations are constructed. The results are summarized using graphs and figures.
Deformation mechanism coherent migration of charges in thin film
Authors: Khudaiberganov T , Bukharov D , Arakelian S 
Published: December 2021

Abstract
We present new mechanism of the charge transport in thin films based on coherent migration of the deformation of the nanoclusters potential, which carries with it an electron. We represent correlation between deformation and charges as the distorton-inverson quasiparticle. This effect is based on the inversion of the potential energy of nanoclusters due to the Jahn-Teller effect in a nanocluster, when charges flow in a network of nanoclusters. The distorton-inverson is quasiparticle are consisted the distorton and electron or hole, this quasiparticle similar an inverson in the Watkins effect. A distorton is quasiparticle which appears itself in the effects of deformation of the potential of the nanocluster with not closed shell. This quasiparticle is similar a defecton in the Watkins effect. We are calculated transmission spectrum and dispersion properties this quasiparticle.
Deposition of GaN nanoparticles on the surface of a copper film under the action of electrostatic field during the femtosecond laser ablation synthesis in ammonia environment
Authors: Kochuev D A , Chernikov A S , Chkalov R V , Prokhorov A V , Khorkov K S 
Published: December 2021

Abstract
In this article, we show the possibility for obtaining and deposition of gallium nitride nanoparticles under the action of femtosecond laser radiation. Using the developed setup for thermal vacuum deposition of copper on silicon plates, we obtained the thin-film substrates following by the deposition of gallium nitride on them. The gallium nitride was formed by applying the femtosecond laser radiation to the gallium targets in ammonia medium. The controlled collection of ablation products following by their removal from the processing area by means of electrostatic field was used in the setup in order to efficiently collect gallium nitride nanoparticles. The formation of gallium nitride nanoparticles is verified by the results of X-ray diffraction analysis.
Efficient realization of infrared coherent radiation by the method of parametric light amplification in nonlinear photonic crystals
Authors: Sabirov O , Akbarova N , Atadjanova N , Sapaev U 
Published: December 2021

Abstract
The process of parametric amplification of light from short laser pulses in nonlinear photonic crystals is analyzed numerically. The calculations were carried out taking into account the effects of the dispersion of the medium up to the third order and cubic nonlinearity of the Kerr type. It is shown that a change in the size of domains can significantly affect the formation of a signal wave pulse. On the basis of the results obtained, we analyzed the optimal values of the domain size at which the efficient energetic generation of the signal wave is observed.
A fluorescent dissolved oxygen sensor with autocalibration based on ruthenium (II) tris-bathophenanthroline complex
Authors: Plyaka P , Demekhin O , Svetlichnyy D , Zagrebaev A , Budnik A 
Published: December 2021

AbstractThe study describes a submersible fluorescent dissolved oxygen (DO) sensor suitable for aquaculture facilities. The sensor is based on the quenching of fluorescence from ruthenium (II) tris-bathophenanthroline complex, [Ru(dpp)3]2+. One of its precursors, bathophenanthroline (BPhen), was obtained by a green approach with less aggressive reagents than in a classical synthesis. It was embedded in a polymer membrane and attached to a glass window to fabricate a sensing element. The composition and functioning of the sensor are described. It uses an additional red LED for automatic calibration and correction of measurements due to photodegradation of Ru(dpp) over time. The intensity of the red light reflected from the active Ru(II) centres indicates their concentration and allows for automatic correction of the calibration factor. The sensor has demonstrated good linearity in calibration tests; its readings were independent of the presence of common inorganic ions in water, which might interfere with the results. This novel low-cost sensor with autocalibration is expected to be a long-term solution for aquaculture.
Coronal mass ejections and high-speed solar wind streams effect on HF ionospheric communication channel
Authors: Vybornov F I , Sheiner O A 
Published: December 2021

AbstractThis article analyzes the degree of solar coronal mass ejections and high-speed solar wind streams influence on the ionospheric communication channel in the short-wavelength range. Regularities in the coronal mass ejections influence on the parameters of the ionosphere are revealed. It is shown that there is a decrease in the values of the used differential parameter of critical frequency of the ionosphere F2 layer after the onset of coronal mass ejections of the loop type, while no significant changes are observed from other types of coronal mass ejections. The contribution of the high-speed solar wind flux to the features of the behavior of ionospheric parameters is demonstrated. Deviations of critical frequency and maximum observed frequency of the ionosphere F2 layer indicate a change in conditions in the ionosphere, leading to disruption of radio communication in the short-wavelength range. The results of ground-based measurements of the ionospheric plasma parameters were obtained by the methods of oblique and vertical sounding of the ionosphere. The use of the method of oblique sounding made it possible to obtain data on the state of the ionosphere where there are no vertical sounding stations.
Investigation of the parameters of traveling ionospheric disturbances using a chirp ionosonde
Authors: Vybornov F 
Published: December 2021

Abstract
This article presents the results of experimental studies of parameters of natural traveling ionospheric disturbances of “sickle” type observed at mid-latitudes using linear frequency modulation ionosondes. Technical parameters of the ionosondes used are given. Experiments were carried out on slightly inclined paths in the central part of Russia in 2015 - 2020 in the daytime. The transmitting station was located in the village of Vasilsursk, Nizhny Novgorod Region. Registration was carried out in the city of Nizhny Novgorod. Examples of ionograms obtained in the course of measurements with different structure of perturbations are given. Estimates of development times of disturbances and their frequency range have been made. The structure of the received signal is analyzed. Based on the results of a complex experiment using a network of synchronously operating ionosondes of the same type, the data obtained were analyzed and direction and magnitude of propagation velocity of the phase front of moving disturbance were determined. A possible mechanism for the imitation of one-way vertical motion of a traveling disturbance characteristic of the mid-latitude ionosphere is discussed within the framework of multipath propagation of radio waves.
Analysis of surface acoustic wave properties in CaYAl3O7 single crystal
Authors: Taziev R M 
Published: December 2021

Abstract
The success on the growth of new piezoelectric materials allows sufficiently increase the operating temperature of the surface acoustic wave (SAW) devices from 300°C to 1000°C. A new calcium yttrium aluminate (CaYAl3O7) single crystal of the tetragonal symmetry has piezoelectric properties up to the temperature of 1000°C. The paper presents a numerical study of the surface acoustic wave properties in the crystal. The SAW velocity, electromechanical coupling coefficient and power flow angle are studied for different crystal cuts of CaYAl3O7. It is shown that the maximum value of SAW coupling coefficient (0.24%) is on the Z+60°-cut and wave propagation direction along the X-axis of the crystal. For the Z-cut and wave propagation direction along the X+45°-axis of crystal, the SAW coupling coefficient is equal to 0.2%. These two cuts of the crystal are potentially useful for SAW device applications.