bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of aldol condensation processes on the formation of surface films during friction in ester lubricants
Authors: Boiko M , Boiko T , Kolesnikov I
Published: December 2021

The boundary lubrication mode is usually implemented in conditions of low sliding speeds and high loads. The formation of strong boundary lubricating films under this friction mode determines the operability and durability of the friction units. It is believed that the formation of surface boundary films during friction includes the stages of the lubricant oxidation, and the aldol condensation reaction of oxidized molecules. As a result, high-molecular substances called “friction polymers” are formed. The paper studies the formation of surface films in the presence of substances with different reactivity in the aldol condensation and Claisen condensation reactions. Sunflower oil, bis (2-ethylhexyl) sebacate (DEHS), triisodecyl benzene-1,2,4-tricarboxylate (TC) were used as lubricants. It is shown by ATR IR-spectroscopy of that the common thing for the studied oils is that the C=O and C-O groups participate in the formation of boundary films in these oils. The addition of substances, active in aldol condensation reactions, into lubricants does not accelerate the formation of boundary films. Additives that can chemically interact with iron contribute to the dissolution of the surface oxide film and accelerate the formation of boundary layers. The formation of “friction polymers” occurs when the lubricant molecules interact with the metal surface.
Investigation of changes in the properties of diamond-like films under friction by the XPS method
Authors: Sidashov A V , Boiko M V , Luneva E I , Popov A M
Published: December 2021

The combination of unique physicochemical, mechanical and tribological properties of diamond-like coatings determines the prospects for their use in critical friction units, including those operating in a rarefied atmosphere and vacuum. The properties of diamond-like carbon (DLC) coatings depend on the contribution of the sp2 and sp3 fractions of the carbon hybrid atomic electron orbitals. Modern methods of determining the graphite and diamond proportion in coatings are time-consuming and insufficiently accurate. In addition, the determination of the sp3/sp2 ratio is often difficult due to the displacement of the energy position of the C1s electron line. In this paper, the change in the chemical state of carbon over the thickness of a diamond-like coating is studied by X-ray photoelectron spectroscopy. Analysis of the carbon line fine structure of the differential graphite spectra (sp2 bonds) and diamond (sp3 bonds) allowed us to establish the parameter δ, which determines the ratio of the graphite and diamond components in the DLC coating. Profiling with Ar+ ions of the diamondlike coating surface showed that with an increase in the etching time, the proportion of amorphized carbon increases, which means that the antifriction properties increase with the abrasion of the coating. The obtained regularities allow us to predict changes in the tribological properties of DLC coatings during operation. Ion profiling also allows to determine the thickness of coatings with high accuracy.
Wear resistance discrete management of formative tool
Authors: Kochetov A N , Fisunova E I , Lavrenova T V , Filonenko L A
Published: December 2021

The article is devoted to the organization of management of the application of wear-resistant materials on the formative tool at set intervals by the method of electro-acoustic spraying. A complex highly concentrated effect of the ultrasonic method in a permanent process, based on the pulse energy, which leads to an increase in the plasticity of the material and is not associated with its heating. The law of electro-plastic deformation for a conducting material, taking into account the high density of the acting amperage in the process of active deformation at a constant rate, considered in this article, establishes a clear dependence of the strengthening of the substrate material. The process of concentration of electromagnetic and thermal fields in a conductive material with defects such as a crack makes it possible to use this technology to slow down the propagation of cracks while reducing the concentration of mechanical stresses.
About the dynamic error of strain gauge torque measuring devices
Authors: Manshin Yu P , Yu Manshina E , Geue Mario
Published: December 2021

The dynamic error of devices belongs to the number of errors that are difficult to estimate. The mechanism for forming this error on the example of torsional torque dynamometersis briefly considered as the most common in the practice of research on the energy of agricultural machines. The limiting ratios of frequencies of external influences and natural vibrations of strain-measuring devices are given. Recommendations are made to reduce dynamic error in torque strain analysis. The present review and the accumulated experience of strain gauge research allows us to recommend some directions for reducing dynamic errors in torque measurements. In order for a strain gauge to keep up with changes in torque in its inertial characteristics, it must have the smallest torque inertia. In order to reduce the probability of high-frequency harmonics from the elastic vibrations of the strain gauge, it must be sufficiently rigid. From this point of view, strain rods, strain sprockets, etc., having a moment of inertia greater than that of the same gear parts, are irrational. Based on modern micromodules and power supplies, the system can have a small mass and have no significant effect on the inertial characteristic of the strain gauge.
Detection of radio signals against the background of strong electromagnetic noise in transport
Authors: Myasnikov E , Zaboronkova T , Kogan L
Published: December 2021

The problem of detecting a useful signal in the presence of a strong background noise is considered. To solve it, a statistical approach is used, based on a change in the level of chaos in the system when an additional random or deterministic process occurs, which is probabilistically independent from a set of stochastic phenomena that form background noise. It is shown that the occurrence of this process changes the level of entropy of the measured signal; this fact is the basis of the applied mathematical algorithm. It is based on the elements of the Fourier transform apparatus for the probability density with an appropriate choice of a nonlinear function of the random process under study. The proposed approach, based on variations in the randomness in the system in the presence of a useful signal, makes it possible to record its presence against the background of noise components even at low signal-to-noise ratios. The effectiveness of the method is confirmed both by theoretical justification and by the calculations presented in this work. The condition for the implementation of the technique described in the article, which does not impose restrictions on the studied physical fields and frequency ranges, is the comparability of the width of the probabilistic distribution of the desired useful signal with several intervals of discreteness of the measuring equipment. One of the results of this work is a high sensitivity to the emergence of independent random components.
Ensuring an effective voltage regime in the electrical network when powering ships of the technical fleet and floating objects from the shore
Authors: Denchik Y , Ivanova E , Salnikov V , Gorelov S , Zubanov D
Published: December 2021

The article deals with topical issues of reducing the asymmetry of linear voltages in the electrical networks of water transport enterprises. Asymmetric modes in the electrical network are researched, which defined the need for automated determination of conductive electromagnetic disturbance. A mathematical description of the occurrence process and strategy for determining the conductive low-frequency electromagnetic disturbance by the voltage asymmetry coefficient in the reverse sequence are presented. The parameters of this coefficient are described: mathematical expectation, standard deviation, probability of occurrence during the calculation period. A mathematical model is obtained that represents a conductive electromagnetic disturbance and explains the probability of its occurrence. A method of automated determination of conductive electromagnetic disturbance has been developed. A software product is presented (certificate of registration No. 2016661752), which allows processing the voltage coefficients obtained as a result of measurements in the reverse sequence. The conductive disturbance is determined for the purpose of suppression and ensuring electromagnetic compatibility. To ensure an effective mode by powering ships from the shore and to increase the efficiency of power transmission, a strategy for voltage symmetry in the electrical network is presented.
Expected electromagnetic environment at the energy infrastructure facilities of remote ports (berths)
Authors: Denchik Y M , Ivanova E V , Ivanova M N , Salnikov V G , Zubanov D A
Published: December 2021

The article deals with the issues of electromagnetic compatibility of coastal and floating objects in the waters of ports (berths). The subject of the study is the processes occurring in the electrical network when powering ships of the technical fleet and floating objects from the shore, which determine the need for automated calculation of conductive low-frequency electromagnetic disturbance for their subsequent suppression. An algorithm for calculating the parameters of the electromagnetic environment is presented, which is based on the analysis of the distribution parameters of slow voltage changes. The mechanism of EMD occurrence in voltage deviation is described and a mathematical model explaining the probability of its occurrence is presented. An algorithm for calculating the parameters of the electromagnetic environment based on slow voltage changes in the network is compiled. This algorithm is implemented in the “Program for the study of slow voltage changes by the load changingof the electrical network ". For the object under study, the parameters of the distribution of conductive low-frequency electromagnetic disturbance over a slow voltage change are determined. A block diagram of an automatic voltage regulator implementing the proposed voltage stabilization law has been developed.
Experimental studies of vibration fields of a freight train in the far zone
Authors: Ya Bubnov E
Published: December 2021

The article analyzes the sources of radiation of seismic and acoustic signals of railway transport. To determine the wave structure of the seismic field of freight train in the experiment, a linear antenna was used, located at a distance of 1000 m from the railway track. A fine spectral analysis of the seismic signal reveals the presence of two harmonics in the frequency range 1–6 Hz. One of the dominant in amplitude discrete coincides in frequency with the harmonic of the acoustic signal, which indicates the refraction of the acoustic wave into a solid medium at the location of the seismic sensor. The source of the infrasonic signal at the specified frequency can be the resonant oscillation of the car on the spring suspension elasticity. The second discrete at a frequency of 2.7 Hz remains unchanged during the movement of various trains and is even present in microseismic noise, which indicates the imposition of a layered structure of a solid medium. The propagation velocity of this harmonic of the seismic signal is less than the velocity of sound. The totality of the marked features makes it possible to identify this wave with the surface wave formed by the layer.
Choosing an approach to statistical processing of the ship’s pitching record
Authors: Sichkarev V I , Umrikhin V P , Koloskov A Y
Published: December 2021

The developed instrumentation and software provides discrete values for the angles of a vessel’s list on an operational voyage in sea conditions at specified time intervals.The half-periods of pitching are considered; the half-period and the corresponding pitching amplitude can be obtained in three different ways: as the amplitude from one board to the other one with the reference of the initial peak-to-peak amplitude or with the reference of the final peak-to-peak amplitude; as the time interval of the ship listing on one side between zero roll angles. It was found that each method corresponds to its own, different from the others, amplitude-period statistics. This makes it difficult to compare different registrations and identify the essential reactions of the vessel to the seaway, unless a method is specified for determining the half-periods and linking the roll amplitudes to them. The proposal is justified to unify the processing by defining the half-period as the time of the ship listing on one board with the corresponding amplitude angle of the roll, that is, as the difference of the moments of time between two next values of the zero angle of the roll.
Mathematical description of the cavitation process in the jet apparatus
Authors: Mizgirev D S , Vlasov D V , Vlasov V N
Published: December 2021

The problem of mathematical description of non-steady processes in hydrodynamic systems is currently relevant and requires early resolution. The description of cavitation as a non-steady process is one of the most important issues of hydrodynamics. In this paper, as a result of the analysis and generalization of a priori information, plus transformation of the basic equations describing cavitation processes, a number of expressions are obtained that reflect the behavior of the incompressible fluid main flow in a jet apparatus, taking into account the conduct of hydrodynamic cavitation in it. To create a cavitation process mathematical description, it is proposed to apply an empirical formula for determining the ejected flow pressure. The newly developed mathematical dependencies can be used in the design of jet devices (ejectors, cavitators, ejectors-cavitators) for various purposes in both marine and stationary coastal technological systems for processing fluid media. In particular, it is advisable to use them in the preparation and conditioning of drinking and industrial water, wastewater and oily water purification, etc.
Mathematical model of harmonic movement of a fixed cargo on the deck of a ship
Authors: Kudelin O G , Smirnova E V , Linevich O I
Published: December 2021

The research is aimed at creating a mathematical model that allows describing the movement of cargo fixed on the deck of a ship, depending on a number of physical parameters acting on the cargo. The study is relevant in connection with the need to minimize the harmonic movement of a fixed cargo on the deck and prevent its resonating with the vibration of the vessel. During the development of the model, a number of assumptions were made: the case was considered when the load moves along the deck in one plane, and the fastening system presses it to the surface of the deck with a given coefficient of resistance. Under the given constraints, a mathematical model was created that allows determining the trajectory of the cargo fixed on the deck. The cases are considered: the friction force of the load on the surface is zero, the friction force on the surface is proportional to the square of the speed of movement in accordance with the analytical equations of motion of the object fixed on the deck of the vessel. The analysis of the resulting model will allow us to develop measures to optimize the fastening of cargo on the deck.
Indicators of the critical state of the ship’s stability
Authors: Kochnev Yu , Ronnov E , Gulyaev I
Published: December 2021

According to the main criterion, the vessel stability according to the main criterion is standardized by the Rules of the Russian Register by the assumption that the units of the stability margin are practically equal, which is the ratio of listing and restoring moments characterizing the equality of their work. That is, the current domestic and international standards allow the achievement of a shipborne borderline hazardous state, after which it will either capsize, or an uncontrolled inflow of water into the hull and emergency flooding will begin. The characteristics of the vessel that affect stability during its assessment, both at the design stages and during operation, are determined with some error. It is caused by the assumptions of the Rules to the displacement value determination and the coordinates of the gravity center, incomplete compliance with the predicted cruise conditions, due to the ship falling into possible more severe conditions, the construction of a static stability diagram, which is the dependence of the reduced restoring moment on the inclination angle, with a flat waterline, while it is three-dimensional, and other factors related to the vessel’s type and purpose, which are not taken into account when calculating stability. In this paper, we consider a group of such factors, in relation to ships of inland and mixed (river-sea) navigation, the features and reasons for their occurrence, taking into account in verification calculations. A mathematical stability safety factor form, reflecting the expected increments of permissible values, which will improve the safety of the ship, is proposed.
Assessment of the impact of the technical condition of the cylinder-piston group parts on nitrogen oxide emissions
Authors: Roslyakova O , Zaitsev V , Panov D
Published: December 2021

Nowadays, a lot is paid to environmental protection issues, including those related to reducing emissions from ships of the sea and river fleet, which is reflected in many works. Constant control over the content of harmful emissions in the environment forces us to deal with the issues of reducing emissions from diesel engines at the design stages and during operation. The solution to this problem allows us to consider 2 directions: constructional and the use of special equipment for capture and neutralization. In the best case, a combined method can be used, i.e. constructional with the use of capturing equipment for harmful components in diesel exhaust gases. This paper presents an analysis of the influence of various factors that reduce the load on the atmospheric air from nitrogen oxides of marine diesel engines, namely, from the operating settings of the diesel engine and its wear. On the ships of the river fleet, diesel engines are used with various mixture formation with volumetric, volumetric-film, vortex mixture formation. The leader in the listed group is the volumetric mixture engines. The paper provides an assessment of the research carried out to analyze various methods of influencing the working process of a diesel engine - the type of mixture formation, wear of the cylinder sleeve in order to determine their influence on the formation of NOx emissions.
Flaw detection of ship equipment parts
Authors: Kuznetsov A , Ivanchik S
Published: December 2021

The need for non-destructive testing is regulated by the rules of the Russian River Register, which can determine the choice of the method of non-destructive testing and the procedure for its implementation. Non-destructive testing methods used in naval mechanical engineering are: visual and measuring control, ultrasonic control, radiographic control, capillary control, magnetic control, eddy current control. Each of the methods, due to the difference in the implemented physical principles, has its own advantages and disadvantages, which impose restrictions on the flaw detection of parts. The analysis of the sculpted defects of ship equipment and machines, depending on the manufacturing method and operating conditions, was carried out. The limitations on the use of non-destructive testing methods are shown. Examples of non-flaw detective parts are given, the control of which is difficult, as well as flaw detective parts that can be controlled with a guaranteed condition for detecting defects. The advantage of the method of magnetic memory of metal is indicated, relative to other methods of non-destructive testing. Using the example of a piston pin of a marine diesel engine NVD 36, a comparative analysis of the applicability of ultrasonic testing methods, the magnetic memory method and the penetrating solutions method for detecting fatigue cracks was performed. The results of the control show that the applied methods confidently identify fatigue cracks in the controlled parts, machines and mechanisms of ship equipment.
Spectral analysis method of electrophysical non-destructive testing data
Authors: Surin V , Beketov V , Ghazal Ayman Abu , Alwaheba Anas
Published: December 2021

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The 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

This 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

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

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.
On the methods of recognition and classification of laser reflection points based on the Terrasolid software module on the Bentley Microstation platform
Authors: Dyachenko R , Gura D , Kiryunikova N , Lesovaya E , Khusht N , Akopyan G
Published: December 2021

Nowadays, the use of the three-dimensional laser scanning technique in performing various scientific research comes to the fore, since this technology is one of the most developed and effective methods for analyzing the state of transport infrastructure objects and geodetic monitoring. The purpose of this paper is to develop an author’s algorithm for the classification of laser reflection points, based on the specialized Terrasolid software on the Bentley Microstation platform. The object of the research is the campus of the territory of the Federal State Budgetary Educational Institution of Higher Education “Kuban State Technological University”. The subject of the research is the possibility of optimizing the process of classification of laser reflection points on the campus of the university territory. The result of the study is the author’s algorithm for the classification of laser reflection points.
Massive crop expansion threatens agriculture and water sustainability in northwestern China
Authors: Lai Jiameng , Li Yanan , Chen Jianli , Niu Guo-Yue , Lin Peirong , Li Qi , Wang Lixin , Han Jimei , Luo Zhenqi , Sun Ying
Published: December 2021

Northwestern China (NWC) is among the major global hotspots undergoing massive terrestrial water storage (TWS) depletion. Yet driver(s) underlying such region-wide depletion remain controversial, i.e. warming-induced glaciermelting versus anthropogenic activities. Reconciling this controversy is the core initial step to guide policymaking to combat the dual challenges in agriculture production and water scarcity in the vastly dry NWC toward sustainable development. Utilizing diverse observations, we found persistent cropland expansion by >1.2 × 104 km2 since 2003, leading to growth of 59.9% in irrigated area and 19.5% in agricultural water use, despite a steady enhancement in irrigation efficiency. Correspondingly, a substantially faster evapotranspiration (ET) increase occurred in crop expansion areas, whereas precipitation exhibited no long-term trend. Counterfactual analyses suggest that the region-wide TWS depletion is unlikely to have occurred without an increase in crop expansion-driven ET even in the presence of glaciermelting. These findings imply that sustainable water management is critically needed to ensure agriculture and water security in NWC.