bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimize the maintenance activity with computer application
Authors: Crisan L M , Crisan A E , Brebenariu D , Borza I
Published: February 2021

The paper contains a few knowledges about the maintenance activity to establish an optimal maintenance strategy with computer application. Maintenance activity is theoretically analyzed by finding a logical scheme for implementing a maintenance strategy and a brief description of the advantages of implementation a computerized maintenance management software.
Biogas production on lab-scale: utilization of wastewater from Hunedoara treatment plant
Authors: Ivanovici M , Cioabla A E , Lelea D , Popescu F , Dunga L I , Ordodi L V
Published: February 2021

In the present work, the potential of wastewater procured from a local treatment plant situated in Hunedoara in order to produce biogas was assessed in anaerobic co-digestion process. Finding appropriate combinations of feedstocks involved in the process represents a key factor in obtaining high biogas amounts and also high quality of biogas. Therefore, a case study was carried out in a lab-scale installation for biogas production using a suspension consisting of wastewater, animal (cow and chicken) slurry and degraded corn. The wastewater and animal slurry were selected as the main feedstock, providing for the microbial community required in the anaerobic digestion, in a volume ratio of 3:1 animal slurry to wastewater. Moreover, the feedstocks were subjected to several characterization methods: determination of total content of carbon, hydrogen and nitrogen and the content of volatile matter using European Standards. The process was performed in thermophilic conditions and controlled mixing of the suspension for a period of 24 days. The performances were appreciated by monitoring the amount of the produced biogas and the main gaseous components of the biogas: CH4, CO2 and H2S.
Improving multi-material structures using topological optimization and the modified SIMP method
Authors: Zhigalov M V , Bodyagina K S , Krysko V A
Published: February 2021

This paper proposes to use a modified SIMP method to solve the problem of topological optimization of structures containing components of more than two different materials, which must be distributed in such a way as to obtain the best structural characteristics using one continuous design variable. The paper demonstrates the effectiveness of the proposed method by the example of solving the problem of topological optimization of a structure made of multimaterial. With the help of such a solution, it is possible to obtain reliable structures with improved mechanical characteristics, which can be used to solve real problems of design and manufacture of complex structures.
Econometric modeling of economic factors’s impact on the labor force per capita
Authors: Liskina E Ju , Davydova E I
Published: February 2021

In this article, we study the impact of a number of economic factors on the number of workers per capita. We use the panel data analysis method. We found that the best model is the one with fixed effects. We have identified the factors that have the most significant impact on the explanatory variable. The number of vacancies per capita, the capacity of outpatient clinics and the number of university students per capita have a positive statistically significant effect on the labor force per capita. The capital-labor ratio, the population per doctor and the total living space per inhabitant on average have a negative statistical effect on the labor force per capita. The values of individual effects of the regions were positive.
The scenario modeling of regional competitiveness risks based on the Chapman-Kolmogorov equations
Authors: Veshneva I , Chernyshova G
Published: February 2021

The paper is devoted to the development of analytical tools for assessing the dynamics of risks to the competitiveness of Russian regions within the conditions of incomplete information. The choice of analysis methods for assessing the risk dynamics was substantiated. A solution based on the implementation of homogeneous Markov models with a discrete set of states and continuous time was proposed, it allowed to assess the probability of risks affecting regional competitiveness. A hierarchical structure of factors that determine the risks of regional competitiveness was formed as a cause-and-effect graph. Corresponding systems of Kolmogorov – Chapman differential equations were obtained and solved. An example for analyzing a 3-element minimal cut set of a cause-effect graph was presented. A set of scenarios for the study of risks and their combinations in various conditions was proposed. The solution was obtained for three leading Russian regions. For a set of scenarios, numerical assessments of risk factors that significantly affect the decline in the competitiveness of regions have been fulfilled. The study results made it possible to rank the effects of critical event occurrence, to identify the most significant risk factors for the loss of sustainable development and competitiveness for the Russian Federation regions.
Parameter tuning of a genetic algorithm for finding central vertices in graphs
Authors: Vlasov A , Khomchenko A , Faizliev A , Mironov S , Grigoriev A
Published: February 2021

This paper studies a genetic algorithm for finding the central vertices in graphs. The algorithm uses a different approach to the solution method presentation and describes a new insight in the crossover process. Studies are conducted to find the optimal parameters of the genetic algorithm such us crossover probability, mutation probability and population size. Based on the results, it can be claimed that with the right parameters, our algorithm shows good running time results with high accuracy of the correct answers.
XXXV International Conference on Equations of State for Matter
Authors: Fortov V E , Khishchenko K V , Karamurzov B S , Sultanov V G , Kadatskiy M A
Published: February 2021

This paper is a preface to the proceedings of the XXXV International Conference on Equations of State for Matter, which was held at the Cheget pension in the village of Terskol, in the settlement of Elbrus, in the Kabardino-Balkar Republic of the Russian Federation, from March 1 to 6, 2020.
Equation of state for vanadium at high pressures
Authors: Khishchenko K V
Published: February 2021

An equation of state for vanadium is proposed over a wide range of densities and pressures in the form of an analytic function of pressure on the specific volume and internal energy. The calculated cold curve and shock adiabat are compared with the available data from static and dynamic compression experiments. The developed equation of state can be used to simulate physical processes in vanadium under conditions of high energy density.
Lanthanum group: Detection and correction of errors in orbital binding energy measurements of internal shells
Authors: Shpatakovskaya G V
Published: February 2021

Experimental data on electronic binding energies in a ground state of lanthanides are analyzed. Internal individual shells K, L, M, N are studied in detail. The data scatter is discussed. Atomic number similarity law of orbital binding energies is shown and deviations from it in some experimental results are treated as measurement errors. Polynomial interpolation of patterns makes it possible to restore missing and correct erroneous data. Comparison is made with experimental data from other sources and theoretical results.
Method of verification of performance of composite package for protection of thin-walled constructions against non-stationary one-sided loadings
Authors: Ostrik A V , Nikolaev D N
Published: February 2021

Computing-experimental method of verification of operability of composite porous package for protection of thin-walled constructions from non-stationary one-sided loadings is proposed. A set of explosive devices for generate loads of the required space-time distributions is described. Two new explosive devices for generation of low-pulse loads of microsecond duration with low difference in loading time at the surface of the tested composite constructions are considered. Time deformation profiles of glass-plastic cylindrical shell under low-impulse load of microsecond duration are given. It is received that use of wire or foil sensors for measurement of deformations give close results when the shell stage of deformation of glass-plastic thin-walled constructions is investigated.
Electrical resistivity of zirconium carbide at 1200–2500 K
Authors: Kostanovskiy A V , Kostanovskaya M E , Zeodinov M G , Pronkin A A
Published: February 2021

Zirconium carbide ZrC produced from nano-sized powders is a new material; its properties have not, in fact, been studied. We present the experimental results on the electrical resistivity of the zirconium carbide within the temperature range of 1200–2500 K. The ZrC specimens were prepared by spark plasma sintering from nano-size particles at a temperature of 2100 K. The goal of the present work is to compare the obtained results of the electrical resistivity with data for ZrC produced by traditional methods.
Periodic error while processing data from a velocity interferometer system for any reflector
Authors: Kazieva T V , Gubskiy K L , Kuznetsov A P , Pirog V A , Tishchenko I Yu
Published: February 2021

When processing experimental data with systems such as velocity interferometer system for any reflector (VISAR), periodic measurement uncertainty arises. The appearance of its uncertainty is investigated and computer modeling of signal processing with random noise is carried out. Analytical dependences of the error value on the signal-to-noise ratio and signal phase are obtained. Methods of reducing this error are considered.
Dynamics of carbon nanostructures in the benzotrifuroxan detonation
Authors: Satonkina N P , Ershov A P
Published: February 2021

The paper discuss the electrical conductivity in detonating benzotrifuroxan. The obtained data demonstrate that the primary carbon condensation takes less than several nanoseconds time.
Effect of mechanical activation on combustion characteristics of Al–CuO powder mixture
Authors: Ananev S Yu , Grishin L I , Yankovsky B D , Kirilenko V G , Dolgoborodov A Yu
Published: February 2021

This paper presents the results of experiments carried out to reveal the influence of the initial parameters of the thermite mixture Al–CuO on the signs of a chemical reaction between its components. Initial parameters were the characteristics of the starting components, preparation conditions and characteristics of the mixture and samples, experimental schemes, methods of initiation. The most important parameter was the preliminary mechanical activation of mixture. The prepared mixture with controlled porosity was placed in experimental assemblies and a chemical reaction was initiated. Values and tendencies of the brightness temperature and the propagation rate of reaction area were determined for different initial parameters of mixture and initiation conditions. The reaction in the volume of the experimental assembly goes into flare combustion in open space. Values of brightness temperature at the stage of flare formation have a stochastic character, determined by the random distribution of reaction sites in the initial volume of the components. A high-speed camera, a pyrometer, photoelectronic and electrocontact sensors were used as diagnostic tools. The final goal of the study is to optimize parameters of mechanical activation of mixture for its effective applying in various conditions.
Study of combustion wave propagation in linear charges from mechanically activated thermite mixtures
Authors: Yankovsky B D , Dolgoborodov A Yu , Grishin L I , Ananev S Yu
Published: February 2021

The combustion wave propagation in Al–CuO and Al–Bi2O3 termite mixtures was experimentally investigated. Waveforms of electric current through the reaction area between electrodes with a given potential difference, chronograms of piezo- and photodiode response, the data of pyrometric measurements, as well as photos of the glowing area were obtained and analyzed. There were revealed the advance filtration of the gas component through pores of mixture, the generation of charges providing considerable electrical conductivity of chemical reaction products, the connection of electrical conductivity dynamics with the optical radiation of the chemical conversion region.
Buoyant flames in near the lower flammability limit hydrogen–air mixtures
Authors: Gavrikov A I , Golub V V , Volodin V V , Mikushkin A Yu , Danilin A V
Published: February 2021

The paper presents the results of large-scale experimental and simulation study of the propagation of premixed near the lower flammability limit hydrogen–air spherical flame. Experiments were carried out in a cylindrical volume of 4.5 m3 covered with thin polyethylene film. The effect of buoyancy and stability of the flame ball in the unconfined volume are studied experimentally and numerically. Numerical analysis of the problem shows that the flame ball becomes unstable after some period of stable propagation that qualitatively corresponds with experimental results. The effect of chemistry in a flame ball propagation process is studied numerically. A comparison of experimental results and numerical simulations are presented. A comparison of numerical simulations with and without chemistry is shown. The subject and results of the study are of critical importance for the industrial explosion safety and hydrogen safety of nuclear power plants.
Laser shock peening
Authors: Inogamov N A , Zhakhovsky V V , Ilnitsky D K , Khokhlov V A
Published: February 2021

Elastic-plastic transformations together with or separately of polymorphic phase transitions are important for the theory of shock waves. Here we discuss changing a classification consisting from elastic, split elastic-plastic, and pure plastic shocks. The split shocks means that there are two jumps: the elastic precursor and plastic shock, and that the elastic jump is independent relative to plastic one. In the split regime the precursor moves with elastic speed of sound overrunning the plastic jump and going further and further ahead relative to plastic jump as time proceeds and becoming weaker and weaker. We oppose the split shock to the one-wave (1W) two zones (elastic and plastic—2Z) shock (1W2Z shock). The 1W2Z wave propagates as whole (therefore one-wave), the plastic shock dynamically supports the elastic one, and the average distance between the jumps does not change in time. The powerful elastic shocks (their amplitudes are much higher than are usually suggested for elastic shocks) were found in experiments with femtosecond laser pulses and confirmed in large scale molecular dynamics (MD) simulations. The observation of the 1W2Z shocks is another important finding coming from MD. The report is devoted to lasers, shocks, and applications. In the second part of the report the generation and propagation of the shocks created for laser shock peening by lasers with ultrashort or nanosecond pulses are considered.
First tests of laser ignition in Wankel engine
Authors: Loktionov E Yu , Pasechnikov N A
Published: February 2021

Laser ignition has been studied in powerful four-stroke engines, not only because of the fast payback, but also because of the more convenient diagnostics in a large scale setup. High-performance compact engines have not been studied, even though advantages of laser ignition could be much more pronounced for those because of harmful emission reduction and multi-fuel abilities. Compact piston engines are considered as an alternative for fuel elements and batteries for portable, automotive and unmanned aerial vehicles. These are characterized by a small combustion chamber comparable to the spark plug inter-electrode gap in axial direction, and its low ratio to bore size. However, for Wankel engines this problem exists at any scale. Laser ignition of lean fuel mixtures in such engines could significantly improve performance by reduced fuel consumption, thermal loads, and a cleaner exhaust. We have investigated the possibility of laser ignition in rotary-piston (Wankel) sub-kW scale model engine using different kinds of fuel mixtures: hydrogen, methane, propane, butane, gasoline, and ethanol based. A custom built compact diode-pumped solid state laser has been used to substitute the original glow plug, respectively. Laser ignition has been found possible and quite beneficial for both types of engines and different fuel mixtures; in terms of NOx emission reduction especially.
Carpet-3 experiment for ultrahigh-energy astrophysics: Current-state and prospects
Authors: Romanenko V S , Petkov V B , Dzhappuev D D , Lidvansky A S , Gorbacheva E A , Dzaparova I M , Kudzhaev A U , Klimenko N F , Kurenya A N , Mikhailova O I , Khadziev M M , Troitsky S V , Yanin A F , Zhuravleva K V
Published: February 2021

The Carpet-3 air shower array is being built at the Baksan Neutrino Observatory, which is located near Mount Elbrus (North Caucasus) at an altitude of 1700 m above sea level. The main aim of the experiment is gamma-ray astronomy in the energy range above 100 TeV to search for diffuse gamma radiation and sources and to study the generation mechanisms of this radiation. The paper provides an overview of the current state of the experiment, as well as its prospects.
A new method for energy gas producing from biomass
Authors: Krylova A Y , Madumarova M M , Shevchenko A L , Sytchev G A , Zaichenko V M
Published: February 2021

Biomass is known to be an alternative source of energy due to its availability and less environmental impacts in comparison with fossil fuels. Widespread of biomass allows us to solve the problems associated with development of local energy production. The developed at the Joint Institute for High Temperatures of the Russian Academy of Sciences technology for biomass energy utilization let to reduce energy consumption. It is achieved through the use of energy released during exothermic reactions, which is accompanied by heating of various types of biomass, which, as it follows from the literature, is realized for the first time in the processes of gas fuel producing. The second energy-saving factor of the developed technology is that the heat source is the gas piston power unit (GPU) combustion products. In this case, a cogeneration scheme is implemented. The results of experiments on the biomass conversion in GPU combustion products medium and numerical calculations in a one-dimensional non-stationary approximation are presented. The method of biomass thermal conversion under development will make it possible to obtain gas fuel or energy supply systems at local fuel and energy resources.
Plasma screening enhancement of thermonuclear reaction rates
Authors: Chugunov A I
Published: February 2021

Plasma screening can enhance the thermonuclear reaction rates significantly. The most pronounced effect takes place in the white dwarf cores and neutron star envelopes; there the enhancement factor can reach as tenths orders of magnitude. Here thermodynamically consistent description of this effect, which does not violate of the detailed balance principle, is discussed.
Dusty plasma environment near lunar surface
Authors: Dolnikov G G , Kartasheva A A , Bychkova A S , Shashkova I A , Kuznetsov I A , Lyash A N , Dubov A E , Popel S I , Zakharov A V
Published: February 2021

The dusty plasmas on the Moon are investigating through the direct detection of the dust particle fluxes on the lunar surface and through the measurements of the parameters of ambient plasma. The PmL instrument is the first device developed both to detect dust particles and to determine the characteristics of the plasma environment. The PmL instrument mounted on future Russian lunar missions Luna-25 and Luna-27 is described in the article. The suggested landing sites of the stations are situated nearby the Boguslavsky crater (nearby 70° south latitude of Moon). The values of the lunar surface potential, Debye length and electric field at a latitude of 70° were obtained in this paper. The distribution of the dust particles near the selected latitudes was also determined. A brief description of the methods for detecting the dusty plasma parameters near the lunar surface was suggested.
Dusty plasmas at the Moon: Effects of magnetic fields
Authors: Izvekova Yu N , Kassem A I , Popel S I , Morozova T I , Zelenyi L M
Published: February 2021

Processes associated with the presence of magnetic fields, which can be important in dusty plasmas on the Moon, are considered. Lower-hybrid wave processes under interaction of the magnetotail of the Earth with dusty plasma near the surface of the Moon are described. Lower-hybrid waves are excited due to the relative motion of magnetospheric ions and charged dust grains, which leads to the establishment of a well developed lower hybrid plasma turbulence. The effective collision frequency characterizing the anomalous loss of ion momentum due to ion-wave interaction, as well as the electric fields arising in the system are found. It is shown that the electric fields excited due to the development of lower-hybrid turbulence are somewhat weaker than those arising due to the charging of the lunar surface under the action of solar radiation. Nevertheless, they are quite significant to affect the electric field pattern above the Moon. The obtained effective collision frequencies should be taken into account when deriving hydrodynamic equations for dusty plasma ions with allowance for their turbulent heating. Problems related to the consideration of magnetic fields, which can be important for detailed study of the dusty plasmas at the Moon, are stated. The possibility of generation of wave motions in the near-surface lunar plasma should be taken into consideration when interpreting the observational data.
Phase coexistence of Yukawa liquid and bcc crystal by the Kofke integration method and a two phase approach
Authors: Reshetniak V V , Reshetniak O B , Filippov A V
Published: February 2021

The present work is devoted to the investigation of the melting line of the body centered cubic Yukawa crystal. Two different methods were applied: numerical integration of the Clapeyron–Clausius equation by Kofke algorithm and study of a equilibrium two-phase system, containing the both liquid and crystal phases. The values of the widely used in practice empirical phase transition criteria were calculated on the melting line. During the melting and crystallization the density of the Yukawa ensemble changes abruptly, which makes it impossible to obtain the self-similar solution of the equations of motion of the particles. As a result, using of a couple of dimensionless parameters lead to errors when calculating the melting line. However results of this paper show that these errors are comparable with the density change, which is less than 3% in the selected range of parameters.
Gas temperature spatial distribution in air corona discharge with plane comb of metal rod electrodes derived from schlieren images
Authors: Pinchuk M E , Lazukin A V , Stepanova O M
Published: February 2021

Gas temperature fields in the air corona discharge with a plane comb electrode system have been determined for the negative and positive polarities of the applied voltage. Highly sensitive schlieren technique used in the study allowed detecting a temperature change in tenths of a degree centigrade at room temperature of the gas flow. The obtained results suggest that the gas in the studied electrode system does not undergo heating at the given range of working parameters.
Near electrode voltage drops in high current high pressure discharges with fast energy input
Authors: Bogomaz A A , Pinchuk M E , Budin A V , Leks A G
Published: February 2021

A dependence of total near electrode voltage drops for high-current high-pressure discharges versus current rise rate into discharge in a range of 109–1012 A/s at initial gas pressure up to 200 MPa is presented. A new technique for the near-electrode voltage drops determination is proposed at conditions of the fast energy input. The technique is based on measuring the characteristics of a shock wave detaching from the discharge channel. Total near electrode voltage drops were increased with the current rise rates from around two hundreds to approximately ten thousand volts.
On plasma thermal spraying by the torch with divergent output nozzle
Authors: Son E E , Vetchinin S P , Gadzhiev M Kh , Yusupov D I , Tyuftyaev A S , Chinnov V F , Sargsyan M A
Published: February 2021

The analysis of the current state of the technological process and equipment for plasma coating of various powder materials has been carried out. To increase the processing efficiency during the deposition of ceramic materials and refractory alloys a novel technological scheme of plasma spraying with a powder feed axially to the cathode was proposed and preliminarily tested. Basing the plasma torch with an expanding channel of the output electrode its plasma-spraying version has been developed in which the sprayed powder was supplied both to the cathode or anode arc striking zone and to the current-free plasma jet. The electrophysical parameters of the argon plasma torch and the speed, size and temperature of particles of sprayed powder were investigated. It was shown that the particle velocity of Al2O3 powder depending on the gas flow and arc current reaches up to 100 m/s. The temperature of the powder particles in the vicinity of substrate at a current of 300 A approximately equals to 2400–2500 K.
Winter rye tolerance to low temperatures after seed treatment with surface barrier discharge
Authors: Gundareva S V , Lazukin A V , Dorofeev N V , Romanov A G , Krivov S A
Published: February 2021

In this work, the experimental results of surface barrier discharge plasma products affection to winter rye seed germination at the initial stage of growth and seedling tolerance to low temperatures are shown. The treatment was carried out for 10, 60, and 180 s in the plane-parallel electrode system with sinusoidal voltage of 2.7 kV with frequency 4.4 kHz applied to the strip electrodes at a distance of 5 mm from each other. It is shown that the treatment has no effect on seed germinating ability. In 180 s exposure treatment mode the stimulation of 3-day seedling shoot and root system length occurs. The freeze tolerance response of two-stage cold hardened seedlings grown from treated seeds shows that both the exposure of seed and the freezing temperature affect on the formation of positive response.
Limitations for lithium-ion batteries application in engine cold cranking
Authors: Fedotov A A , Popel O S , Kiseleva S V , Tarasenko A B
Published: February 2021

This research is devoted to the possibilities of using lithium-ion (Li-ion) batteries operation in engine cold start systems. Down-scale test specimen of LiC6–LiNiMnCo (NMC) and LiC6–LiFePO4 batteries coupled with supercapacitor module were tested in cold cranking mode. The charge currents between Li-ion battery and supercapacitor module are experimentally determined. The actual operating temperatures ranges of such batteries are determined in relation to local climate condition and compared with single lead–acid (Pb–acid) battery. The test results showed that significant limitations exist for current value both for Pb–acid and Li-ion battery. Coupling of supercapacitor module with Li-ion battery slightly improves the situation, but does not guarantee reliable three attempts for engine cold cranking.
Hybrid power-generating system with inertial energy-storage device
Authors: Balakin P D , Dyundik O S , Zgonnik I P , Fedorova M A
Published: February 2021

Detailed quantitative analysis of the energy and technical capabilities of various hybrid power-generating system combinations for a transport machine is performed. Prospective combination of compression ignition engine and inertial energy-storage device made by the superflywheel is shown. Engineering analysis of superflywheel parameters and features of the dynamics of the flywheel drive is given.
Combined drawing with extrusion of square box parts from a square billet
Authors: Bessmertnaya Yu V , Larin S N
Published: February 2021

The effectiveness of the technology of making square box parts can be ensured with the help of new technologies of deformation. This article considers a method combining drawing and extrusion of square box parts from a square billet, which allows achieving high economic indicators. The paper presents a study of the material flow and recommends a variant of the die design, which makes it possible to maximize the material utilization factor and rationalize the stamping technology.
The inertial compensation of the vibroactive force in the oscillating system
Authors: Burian Yu A , Sitnikov D V , Silkov M V
Published: February 2021

Actuators used in active vibration isolation systems of various types are either installed between the oscillating mass and the base, or next to the elastic-dissipative elements of a passive system. The actuator is usually controlled according to information from force-measuring devices. This significantly complicates the implementation of such systems. An active system is considered in which an electrodynamic drive (actuator) is used to compensate for vibroactive forces transmitted to the base. An electrodynamic drive is mounted on the base and controlled by accelerometers mounted on the passive system moving masses and the actuator. Straight-line controlled vibrations of the actuator moving mass provide inertial compensation of vibroactive forces on the base.
Justification and selection of rational parameters of drilling piles of engineering structures (on the example of soil conditions of the Chayandinskoye oil and gas condensate field)
Authors: Gruzin V V , Gruzin A V
Published: February 2021

Solving the problem of rational use of building materials in the development of new fields helps to minimize ineffective consumption of applied resources. The purpose of the conducted research was to develop recommendations on the selection of rational parameters of drilling piles for engineering structures constructed on soils of the Chayandinskoye oil and gas condensate field. Bearing capacity of a base of a vertically loaded friction pile was calculated by means of existing methods. Selection of specific bearing capacity as a target parameter characterizing the efficiency of building materials and bearing capacity enabled to give a comprehensive estimate of influence of structural parameters and natural factors on bearing capacity of bored piles in a foundation soil. A complex nature of pile geometric characteristics and ground conditions’ influence on the target parameter was established during theoretical calculations. For geotechnical conditions of the Chayandinskoye oil and gas condensate field, it was established that the use of piles with a bigger diameter of 0.4-0.5 m and the length of 6 m in soils with a temperature of no more than -2.0 °C and an ice content of no more than 0.2 is rational. Practical recommendations to use the results obtained during the performed studies can reduce inefficient costs of not only material, but energy and time resources in conditions of remote industrial facilities and logistics bases.
Layout Experimental Study of Dynamic Parameters of an Asymmetrical Self-Oscillating Hydraulic Drive
Authors: Kilunin I Yu , Sorokin V N
Published: February 2021

The article describes the developed asymmetric self-oscillating hydraulic drive and a stand for determining its dynamic characteristics. The design feature of the self-oscillating drive is that the switching of the working fluid in the cylinder cavity is made by two spools mounted inside the piston, while the working fluid is supplied to the spools by the hollow rod. The test stand is based on the principle of throttling the working fluid when it flows from one cavity of the loaded hydraulic cylinder to another. Stand tests of the developed drive have shown its reliability at different values of the piston stroke and at different operating pressures. The paper presents the characteristics of the drive when operating under load and at idle..
The efficiency analysis of the turbo air refrigerators for producing solid carbon dioxide from the boiler combustion products flow
Authors: Kondratev N V
Published: February 2021

The paper considers the efficiency analysis of the turbo air refrigerators for producing solid carbon dioxide from the boiler combustion products flow. The process of obtaining solid carbon dioxide in the turbo air refrigerating machine was modelled. A numerical study of the process and degree of solid carbon dioxide freezing in the turbo air refrigerating machine was performed. The range of the boiler power characteristics, where the most effective solid carbon dioxide freezing is possible within the technical specifications of the turbo air refrigerating machines, was determined.
Oscillations simulation of the vibration protection suspended load with a movable base
Authors: Korytov M S , Shcherbakov V S , Titenko V V , Pochekueva I E
Published: February 2021

Reducing the vibration effects on a human operator of a construction, road or handling machine is an urgent task, since the vibration loads produced by the internal combustion engine, vehicle engine interacting with the support surface microrelief, as well as the machine working attachment, adversely affect the machine operator and increase the machine parts and assemblies wear. The operator may develop occupational diseases caused by vibrations. In this regard, the research objective is to develop the mathematical apparatus simulating the dynamic processes of the passive vibration protection systems oscillations at the design stage. Therefore, the problem developing a mathematical model that makes it possible to study the oscillations of a single degree of freedom passive vibration protection systems with any given static characteristic, was solved. On the basis of the dynamic equations of a single translational degree of freedom vibration system describing the vibration protection suspended operator’s seat, the mathematical model solving the differential equation of the system oscillations taking into account the spring loaded mass displacements damping and three-segment static characteristics of the vibration isolation mechanism with limiters was simulated using the package Simulink of MATLAB system. An example of using the developed mathematical model for modelling vibrations of a spring-loaded mass under the sinusoidal external influences is given. The preset vertical displacements of the machine base, i.e. its base chassis act as the external influences. The examples of the obtained simulation results, namely the vertical displacements and accelerations of the spring-loaded mass are presented. The maximum accelerations of the spring-loaded mass were found out to significantly increase, when the machine base forced displacements amplitude exceeds by half of the horizontal section of the quasi-zero static characteristic of the vibration protection suspension.
Efficiency improvement of oil and gas facilities power supply systems
Authors: Kulbyakina A V , Ozerov N A , Batrakov P A , Savelyeva A I , Munin A P
Published: February 2021

Oil and gas refineries have a significant impact on the environment. The paper considers the main harmful substances formed as a result of the manufacturing processes occurring at the enterprises of the given industry and having a negative impact on the atmosphere, hydrosphere and lithosphere. The most significant sources of contaminants have been identified. The paper presents the most promising approaches described by both domestic and foreign authors for developing environmentally friendly, low-waste productions through the complex use of all the components of raw materials, energy resources and industrial wastes to ensure the required processing conditions. The authors developed and proposed the scheme of the power plant comprising the integrated waste disposal in oil and gas refineries, aimed at combining the processes of the thermal utilization of industrial wastes (combustible gases, effluents) with the processes of gasification and energy production (electricity, thermal energy, synthesis gas, water supply), reducing the specific consumption of the fuel gas for the energy resources production and waste disposal, improving the environmental safety and reliability of the facility.
Application of the geometrical models, graphs and elements of robots kinematics as the basic elements of the unified methodology for assurance of accuracy calculating stage in precision axisymmetric products assembling
Authors: Masyagin V B , Primak D D , Volkov I A , Artykh R L , Bazhenov R I
Published: February 2021

The accuracy standards of engineering products, namely geometric parameters, such as tolerances, geometry deviations and surfaces form deviations, are indicative of parts and assembly units quality. The article discusses the integrated approach to the study of accuracy parameters using geometrical models, graphs and elements of robots kinematics as the basic elements of the unified methodology for assurance of accuracy calculating stage in precision axisymmetric products assembling. The integrated approach is to combine the developed techniques into a unified methodology for assurance of accuracy calculating stage in precision axisymmetric products assembling. The implementation of this approach is carried out by a phased study of the construction for all accuracy parameters in in a common reporting format based on key provisions Obtained results suggest quickly make changes to the studied design based on the phased analysis according with the developed integrated approach.
Comparative analysis of aerodynamic characteristics of catalysts for steam reforming methane
Authors: Mrakin A N , Afanaseva O V , Vdovenko I A , Ageev M A , Selivanov A A , Batrakov P A
Published: February 2021

The main results of the aerodynamic resistance estimation of the catalyzing backfill of processes hydrocarbons steam reforming, and also units which implementing the process of thermochemical regeneration of the exhaust gases are considered. Empirical dependences of various authors are presented for determining the resistance coefficient. Expressions which is the most adequately describe the hydrodynamic picture of the ongoing process are determined. The calculated specific resistance is in the range of 25-26 kPa/m, and correlates with indicators of industrial units operated in similar hydrodynamic modes (resistance is 18-31 kPa/m).
Effects of tooling unbalance on surface roughness in end milling
Authors: Nikolaev A , Savilov A
Published: February 2021

The article discusses the issues of surface roughness when milling aluminum alloys. Effects of tooling unbalance are analyzed. The mathematical modeling method was used to calculate residual tooling equipment unbalance values. To assess model adequacy, experiments were conducted according to the fractional three-level four-factor plan. The unbalance effect was determined by regression analysis of the experimental data. Response surfaces were constructed. The experiments were conducted on a modern milling center. The results confirm that the mathematical model is adequate and the degree of surface roughness depends on residual tooling unbalance values.
Modeling of Bending and Radial Hydroelastic Oscillations for a Sandwich Circular Plate Resting on an Inertial Elastic Foundation
Authors: Popov V S , Chernenko A V
Published: February 2021

The paper deals with the development and analysis of a mathematical model for a circular sandwich plate resting an inertial elastic foundation and interacting with pulsating viscous liquid layer. The sandwich plate is the bottom wall of a channel containing a thin layer of viscous liquid. The pressure in the viscous liquid layer changes due to a predetermined pressure pulsation law at the channel contour and its squeeze between the upper channel wall and the vibrating circular sandwich plate. The coupled hydroelasticity problem consisting of the Navier-Stokes equations, the continuity equation, and the dynamics equations for the circular sandwich plate with corresponding boundary conditions was formulated and solved. We studied the viscous fluid motion inside the channel as a creeping one. The elastic foundation was considered in the framework of inertial Winkler foundation model. To write the sandwich plate dynamics equations, we used the kinematic hypothesis of the broken normal. The hydrodynamic parameters of the liquid layer, including its stresses acting on the sandwich plate, were found. The final mathematical model is the system of partial differential equations for studying bending and radial hydroelastic oscillations of the sandwich plate. Its investigation was carried out by the Fourier method. We studied plate dynamic behaviour in the main vibration mode. In particular, the frequency response of the circular sandwich plate were constructed and studied.
The punching mechanism of holes in plates made of fragile material
Authors: Proskuriakov N E , Lopa I V
Published: February 2021

The shock loading of a plate made of fragile material is considered. The hypothesis is accepted that destruction of a plate can happen at the expense of a multiple splitting off of its back part because of action of the reflected pulling stresses and a simultaneous cut of a front part in the form of a stopper because of the action of tangential stresses generated by a wave of compression. It is shown that the destruction of a ceramic plate can happen at the expense of a multiple splitting off of its back part because of action of the reflected pulling stresses and a simultaneous cut of a front part in the form of a stopper because of the action of tangential stresses generated by a wave of compression. Necessary and sufficient conditions a punching of a plate are formulated and probable coordinates of its sections in which there are destructions of the type of a splitting off are determined. The results of numerical calculations are presented. The received formulas can help to pick up the characteristics of the striker providing punching of holes of the necessary diameter in plates made of friable material with beforehand given properties.
Analytical description of the interaction process of a rigid vibratory drum with a compacted surface using the general dynamics equation
Authors: Tarasov V N , Boyarkina I V , Boyarkin G N
Published: February 2021

This study has solved the task of creating the theory of the soil compaction by a rigid vibratory drum on the basis of the usage of the general dynamics equation. When rolling over the deformable soil the vibratory drum performs a compaction operation and represents a mechanical system that is influenced by stationary dynamic forces. A design diagram has been created for the consideration of dynamic interaction processes of the vibratory drum with the compacted soil, where the main parameters are represented by the angle α of the vibratory drum interaction with the soil, angle β of the inclined plane, which simulates the vibratory drum resistance rolling during the soil compaction and vibratory drum geometric parameters. The general dynamics equation allows to obtain an analytical solution of the problem of the vibratory drum interaction with the soil in the form of the sum of elementary works of the tractive force T, load Q on the wheel axles, soil reaction forces on the vibratory drum, and rolling resistance forces. The solution is presented in the equation form of the sum of the elementary works of all the indicated forces, which is equal to zero. Analytical dependences of the vibratory drum rolling moment, rolling resistance force and vibratory drum rolling resistance coefficient over the deformable soil in relation to construction soils of the 1st – 4th strength categories have been obtained. The obtained results can be used when designing vibration rollers for the compaction of deformable media.
Formation of requirements to the laboratory experimental unit under condition of continuation of researches of processes of heat and mass transfer on a model experimental unit
Authors: Trushlyakov V I , Lesnyak I Yu , Urbansky V A
Published: February 2021

Theoretical results of modeling of vacuum process of evaporation of model liquid in closed volume, carried out for experimental laboratory unit (ELU) and experimental model unit (EMU), differing in size, boundary and initial conditions are considered. The parameters of EMU are determined on the basis of the theory of similarity to the processes taking place in the tank of the launch vehicle stage in the field of small overloads, and the parameters of the ELU selected from the conditions of the existing laboratory equipment. The correlation functions of the process parameters (mass and temperature), showing the degree of proximity of the processes, have been calculated on the example of the process of liquid evaporation under vacuum effects for ELU and EMU, obtained by using the ANSYS Fluent software package. In the course of numerical experiments the vacuum pump capacity was varied to ensure equality of Nusselt criterion for ELU and EMU.
Justification of chosen values of the weight coefficients of the compaction value for continuous compaction control systems for vibration rollers
Authors: Tyuremnov I S , Morev A S , Krayushkin A S
Published: February 2021

The problem of monitoring the compaction of road construction materials in structural construction is currently relevant. The methods of quality control of compaction of road construction materials currently used in Russia during quality inspection do not provide a way to estimate more than 0.1% of the total compaction area. Today there is a wide variety of continuous compaction monitoring systems for vibratory rollers. Such systems allow operators of vibratory rollers to monitor the condition of compacted material in real time, which significantly improves the quality of road construction. The operation of most monitoring systems is based on the compaction index obtained from the analysis of the acceleration spectrum of the vibratory drum. When a new soil compaction monitoring system is only starting to be developed, it is necessary to develop and test in the field a new, more perfect compaction indicator, and to compare it with the existing compaction values. A field research has provided us with signals from vibration acceleration sensors placed on the frame of a vibratory drum and acceleration spectra of the vibratory drum using ZETLAB software made by ETMS. To calculate the proposed indicator, the received data was processed in STATISTICA v.10. The final correlation analysis was performed using the CORREL function found in MS Excel 365 and its financial and scientific data analysis tool. As a result of this correlation analysis, it was found that the proposed Compaction Value has the highest coefficient of linear correlation with the value of the dynamic deformation module Evd in all areas of the field research. In this regard, it can be concluded that using the proposed Compaction Value is reasonable in the development of a new continuous monitoring system for compaction of road-building materials with vibratory rollers.
Investigation of plasma parameters of a single-gas ion engine using a single langmuir probe
Authors: Vavilov I S , Fedyanin V V , Yachmenev P S , Stepen’ P V , Lukyanchik A I , Zharikov K I
Published: February 2021

This paper presents the results of an experimental study of the parameters of nitrogen, argon and helium plasma obtained in high-frequency capacitive ring discharge at a pressure of 35 Pa. The parameters were determined by a single Langmuir probe. Work is being carried out as part of a project to develop a backlash ion microwave plasma generator. The object of study is ionized gas formed in the ring capacitance gap of a microwave solid-state generator emitter on the MOSFET transistor MRF284. The power consumed by the microwave generator in the study is no more than 5 W. The work resulted in getting the volt-ampere characteristics of a high-frequency discharge in low-pressure gas and determining the main plasma parameters.