bluuebunny/crossref_metadata_2025_split huggingface dataset:
The destruction of pure metal cathodes during the initiation of direct current arc
Authors: Sargsyan M A , Tereshonok D V , Gadzhiev M Kh , Tyuftyaev A S , Shcherbakov V V 
Published: February 2021

Abstract
In this work, the behavior of cathodes made from pure tungsten and pure hafnium in the direct current electric arc at 200 A and in atmospheric pressured argon medium was investigated. The research was focused on the processes happening with the cathodes during the arc initiation phase (first 100 ms after the power input). The processes of rapid cathode destruction were registered, and can be characterized as the destruction of the cathode in liquid phase due to electro-magnetic forces. Characteristic times of the whole process were recorded, as well as the changes in temperature fields on the cathodes surfaces and the rate of mass loss for both types of cathodes. It has been shown that the initial destruction of the cathode plays a major role in the cathodes resource life.
A low-temperature plasma generator working on nitrogen–propane mixture
Authors: Gadzhiev M Kh , Tyuftyaev A S , Kulikov Yu M , Sargsyan M A , Yusupov D I , Son E E 
Published: February 2021

Abstract
A low-temperature plasma generator of a mixture of nitrogen and propane has been developed, with the possibility of supplying propane to the cathode region, to the arc burning zone, and also to the plasma stream below the arc binding zone. The maximum propane flow rate for a given plasmatron design and plasma-forming nitrogen flow rate, at which the arc is stable, was determined. When propane is supplied into the arc binding zone, the decay products are deposited mainly on the electrodes, and when it’s supplied to the anode after the arc binding, the decomposition products are deposited mainly at the anode exit. The study of the microstructure and analysis of the phase composition of the decomposition products of propane were performed.
Modeling of destructive interaction of hot jet and solid plate
Authors: Muruganandam T M , Son E E , Gadzhiev M Kh , Vetchinin S P 
Published: February 2021

Abstract
Based upon the results of a literature review, a set of physical parameters suitable for quantitative comparison in experimental and numerical studies is determined. The review showed the feasibility of modeling the process of the outflow of an immersed jet of inert gas into the surrounding space and the evolution of a free shear layer formed by hot and cold gases to analyze the process of convective and diffusion transport of various types of particles. In the model formulation we consider the problem of solid destruction by a melt of the same substance, as well as by a nitrogen stream at high temperature. The test simulation of the problems of two-phase interaction of a immersed jet of molten liquid and hot gas, on the whole, qualitatively showed the reproduction of the main characteristics of the flow: the generation of large-scale vortices around the jet in the induction zone, the oscillations of the jet when it collides with an obstacle, and the shape of the cavity formed.
Ion composition of nitrogen plasma jet with carbon admixture
Authors: Kavyrshin D I , Chinnov V F , Korshunov O V , Sargsyan M A , Khromov M A , Shcherbakov V V 
Published: February 2021

Abstract
With the aim of studying nitrogen plasma flow impacting graphite surfaces, we investigated the evolution of a plasma jet moving from the nozzle of the plasma torch to the target. The motion is accompanied by a decrease in temperature from 10 to 7 kK with a loss of ≈ 60% of the deposited energy and an increase in the density of carbon-containing impurities with partial preservation of the local thermodynamic equilibrium. The main reactions are thermal processes of the formation and decomposition of molecules, dissociative recombination and recharging of nitrogen ions. In the presence of carbon impurities, this set is supplemented with the substitution reaction C + N2 ↔ CN + N, electron-collision processes of stepwise ionization and recombination, and a whole ion-molecular cascades of reloads and substitutions. It has been established that a small admixture of carbon (∼ 0.1%) manifests itself only in ion-molecular kinetics, increasing the electron concentration, determining the ionic composition of the plasma, and thereby violating the equilibrium between its neutral and charged components. This leads, in particular, to the recombination nonequilibrium distribution of carbon atoms over electronic states. Other carbon-containing impurities (CN and C2) are not significant.
Investigating wire breakage during EDM with fractographic analysis
Authors: Bredgauer Iu O , Polonyankin D A , Fedorov A A , Blesman A I , Linovsky A V , Postnikov D V 
Published: February 2021

Abstract
Wire electrical discharge machining (WEDM) is widely used in various fields of production. Its disadvantages include a relatively low productivity rate caused by wire breakages among other factors. In this article, the method of fractographic analysis is used to study a wire that has undergone a breakage during machining. The results indicate that the tool–electrode is subjected to mechanical tension followed by a ductile fracture. The most probable reason of wire breakages is a decrease in the wire cross–section, which can be caused by an electrodes short circuit.
Heat-mass exchange processes dynamics in fires in multi-apartment buildings and its impact on safe people evacuation probability
Authors: Khrapsky S F , Bedrina E A 
Published: February 2021

Abstract
The urgency of people safe evacuation problem from small and medium storeys typical residential sectional type multi-apartment buildings, which in accordance with current regulatory requirements are not equipped with technical means of fire detection and notification of residents, are not equipped with active smoke ventilation systems and do not have effective structural evacuation solutions is shown. Based on modern software systems, numerical experimental studies were conducted to assess the dynamics impact (intensity rate impact) of heat and mass exchange combustion processes on the people evacuation parameters and the corresponding rate of increase dangerous factors for human viability in fire. The time intervals available to residents for safe and timely evacuation are calculated, depending on the typical residential premises fire load characteristic quantity. Taking into account the results obtained, practical measures aimed at improving the people safety in fires in residential multi-apartment buildings are proposed for implementation.
Road roller operator’s vibroprotection system improvement
Authors: Korchagin P A , Teterina I A , Korchagina E A 
Published: February 2021

Abstract
The article reflects the results of the theoretical and experimental studies aimed to reduce dynamic influences on a road roller operator’s workplace by changing the design parameters of the ‘supporting surface – road roller – operator’ dynamic system. The results of the experimental studies on the modernized hinged tie rods construction are presented. The rigidity coefficients of the springing elements of the hinged tie rod ends are determined. The dependence of the rigidity coefficient on the deformation value of the hinged tie rod ends is graphically presented. A comparative analysis of the experimental studies results aimed at determining the value of the dynamic influences on an operator’s workplace (a cabin floor and a seat) carried out with a road three-axle three-wheeler roller with plant and modernised hinged tie rods. The transmission coefficients from the internal combustion engine to the cabin floor and the operator’s seat are obtained at small, medium and high engine speeds, with a vibration exciter switched on and off. The conclusions on the legal use of the modernised hinged tie rod structure as a component of the vibroprotection system of a road roller operator have been drawn.
Roller vibroprotection mechanism with a quasi-zero stiffness section
Authors: Korytov M S , Shcherbakov V S , Titenko V V , Pochekueva I E 
Published: February 2021

Abstract
A new numerical method for designing the profile of the support surface for moving the vibration protection mechanism pressure roller for the operator’s seat in road and construction machines has been developed. The roller vibration protection mechanism of the type under consideration provides for the required force characteristic with a quasi-zero stiffness section of a given long length. This advantage of the roller vibration protection mechanism makes it possible to recommend it for application in vibroprotection systems for road and construction machinery operators. Difficulties in creating such mechanisms are caused by the nonlinear nature of the system of algebra-differential equations that describe the relationship between the static force characteristic and the geometry of the mechanism support profile. That is why it is difficult to obtain a solution in the analytical form of a support surface profile and requires a numerical solution. As an example of the efficiency of the proposed method, we obtained a support surface profile for a roller vibration protection mechanism with a given force characteristic in the form of a three-segment spline with 0.1 meters length quasi-zero stiffness section. The developed method lets us use the specified parameter values as the initial data. In the Simscape Multibody application of the MATLAB system, a simulation model of a dynamic vibration protection mechanism system was developed. It allows simulating movements and studying the modes of this mechanism at the design stage. We give an example of the time dependencies of the mechanism points coordinates obtained using a simulation dynamic model for damped free vibrations.
Vibration protection system with nonlinear elastic and damping characteristics
Authors: Korytov M S , Shcherbakov V S , Titenko V V , Pochekueva I E 
Published: February 2021

Abstract
One of the leading areas of improving the road construction machines is to increase the comfort and safety of the human operator by reducing vibration effects. Therefore, the most simple and available way to implement this direction is applying the passive vibration isolation of a human operator’s seat. Vibration protection mechanisms of such seats typically have one translational degree of freedom. Studying the single degree of freedom vibration protection systems under the various external influences, in particular, with kinematic excitation of base displacements is a relevant topic of investigations. The research objective is to develop a mathematical model of a vibration protection system with variable stiffness and damping coefficients of a vibration isolator, as well as to optimize the mathematical model parameters. The following problems were solved: the development of the calculation model, the compilation of the model differential equations system, the description of the dependences of the stiffness force and damping coefficient of the vibration protection system using two-point Hermite splines. A type of the kinematic excitation characterized by one parameter - a constant base velocity, the evaluation criterion of the system response to this kinematic excitation - the maximum object acceleration and the integral criterion for assessing the system response to a spectrum or excitation range at the different speeds were proposed. The parameters specifying the type of the dependences of the stiffness force and damping coefficient of the vibration isolator were optimized by the integral criterion. The results are represented in the form of the mathematical model formulas, displacements and accelerations graphs and optimized values of the system parameters.
Experimental investigations of the parameters of liquid evaporation process under acoustic-vacuum exposure
Authors: Trushlyakov V I , Lesnyak I Y , Novikov A A 
Published: February 2021

Abstract
Experimental investigations of the process of liquid evaporation under conditions of acoustic-vacuum exposure were conducted. Based on the obtained values of the evaporating liquid mass and the liquid vapor pressure in a closed container, a resonance effect is revealed. The emergence of the resonance effect is characterized by the active boiling of the liquid when the frequency of the system “steam-gas mixture + cupola + vacuum chamber + liquid layer” coincides with the frequency of the acoustic exposure under conditions of reduced external pressure. To measure the vapor pressure of the liquid, a cupola was introduced into the experimental stand, which makes it possible to increase the vapor pressure of the liquid and register its value with the equipment used. The calibration characteristic of laboratory scales is obtained as a dependence of the change of cargo weight on the pressure values in the vacuum chamber. Using the obtained calibration characteristic of laboratory scales operating under acoustic-vacuum exposure, the values of liquid mass change are obtained at different values of external pressure in the vacuum chamber. The results obtained can be applied in the field of acoustic-vacuum drying and cleaning of different surfaces.
Influence of the charging pressure of the hydraulic pneumatic accumulator of the communal machine control device on the pressure force of the brushed working body
Authors: Tsekhosh S I , Ignatov S D , Shcherbakov VS , Kvasov I N 
Published: February 2021

Abstract
The article is devoted to the actual problem of increasing the efficiency of cleaning the roadway with a communal machine. To increase the cleaning efficiency, it is necessary to provide the required pressing force and thus the required area of the contact spot between the brush pile and the surface to be cleaned, which can be done by using a position control device for the brush working equipment.
Research methods. In the process of research were used the following methods: analysis, synthesis, ascent from the abstract to the concrete. The results of the study of the influence of the parameters of the control device on the criterion of the efficiency of the working process of the communal machine are presented.
Results. As a result of the analysis of the process of interaction of the brush working equipment with the surface being cleaned, the dependences connecting the standard deviation of the pressing force of the brush working equipment to the surface to be cleaned from the required value, taking into account the wear of the pile and the charging pressure of the hydraulic pneumatic accumulator, were revealed, their approximation was carried out, and the regression equation was obtained.
Conclusions. The studies carried out made it possible to obtain regression equations which are used to determine the optimal value of the standard deviation of the pressing force from the required one for different degrees of wear of the pile, depending on the charging pressure of the hydraulic pneumatic accumulator. The research results can be applied in the design of automatic control systems for the position of the working bodies of construction and road machines.
Load distribution factor along the power transmission lines as a factor in choosing a voltage class
Authors: Bogachkov I M , Khamitov R N 
Published: February 2021

Abstract
Gas fields differ from industrial enterprises by long power transmission lines with low electrical loads (low density), which grow many times during the life cycle. Power supply to gas well clusters is carried out according to the scheme - “main circuit with one through line with transformer substations distributed along the line”. The distribution of transformer substations along the transmission line affects the voltage loss, and, consequently, the choice of voltage class. The purpose of the research is to quantify the distribution of transformer substations along the power line to develop a mathematical model for calculating the optimal voltage class. To achieve this goal, the following tasks are solved: five power supply schemes are built for gas well clusters; electric moments are calculated for each scheme; the load distribution coefficient is determined. The problems were solved using an experimental-theoretical method (analysis and synthesis) and a software product – Mathcad. As a result, the coefficient is calculated in the work - for even load distribution, when placing the entire load at the end of the line and when placing the load at the beginning of the line.
Kinematic model of the parallel approximation method
Authors: Dubanov A A , Ausheev T V 
Published: February 2021

Abstract
This article considers a model of the pursuit problem using the parallel approach method. The purpose of this article is to modify the method of parallel approach in order to take into account the case when the pursuer’s speed vector is not directed at the target at the pursuit beginning moment. In addition, in the model discussed in the article, the pursuer cannot instantly change the movement direction. That is, the condition is imposed that the pursuer’s trajectory curvature radius cannot be less than a certain value. The proposed method is based on the fact that the pursuer, choosing a step at the iteration stage, will try to follow the predicted trajectories. Based on the materials of the article, we have written the test program that calculates the pursuer’s trajectory, taking into account the conditions set out. The completed animated image visualizes the change in the coordinates of the pursuer, the target, and the predicted trajectories from time to time.
Kinematic model of the pursuit problem on a plane by the chase method
Authors: Dubanov A A , Ausheev T V 
Published: February 2021

Abstract
This article considers a kinematic, geometric model of the pursuit problem on a plane by the chase method, where the pursuer cannot instantly change the direction of movement, while moving at a constant modulo speed. The initial speed of the pursuer is not directed at the target when the pursuit begins. In order for the speed vector of the pursuer to be directed at the target after some time, we have developed a method that is based on following the trajectory that connects the pursuer and the target. This trajectory takes into account the inertia of the pursuer in the sense that the radius of curvature of the trajectory is not less than a certain threshold value. Based on the materials of this article, test programs were written and an animated image was made.
Geometric modeling of torse surfaces in BN-calculus
Authors: Konopatskiy E V , Bezditnyi A A , Litvinov A I 
Published: February 2021

Abstract
The paper presents a general approach to geometric modelling of torse surfaces in BN-calculus, based on the definition of the torse as the geometric location of tangents to its edge of return. In this paper, a method for determining the curves – edges of the return of the torse surface, using the geometric properties of the point definition of the curve in plane and spatial simplices, is proposed in general form. Examples of constructing geometric models of torse surfaces, for which algebraic and transcendental spatial curves were used as the return edge, are given.
Automatic classification method of the speaker’s emotional state by voice
Authors: Koshekov K T , Kobenko V Yu , Anayatova R K , Savostin A A , Koshekov A K 
Published: February 2021

Abstract
This article addresses the problem of developing an effective method for automatically classifying the aviation personnel emotions (announcer) by voice. To this end, it is possible to create a dictatorial independent algorithm capable of performing a multi-grade classification of the seven emotional states of a person (joy, fear, anger, sadness, disgust, surprise and neutrality) on the basis of a set of 48 informative features. These features are formed from the digital recording of the speech signal by calculating Mel Frequency Cepstral coefficient and the main tone frequency for individual recording frames. The increase of informativeness and the reduction of the dimension for the Mel Frequency Cepstral coefficient is achieved by processing said coefficients with the aid of a deep, convergent neural network. The model of the classifier is realized by means of logistic regression, which was trained on the basis of emotionally colored English speech samples by these informative features. As a result of the training on the test sample, the correct recognition response accuracy is equal to 0.96. The inventive solution can be used for improving human-machine interfaces, as well as in the field of aviation, medicine, marketing etc.
Optimization of passive activator parameters for printing machines
Authors: Litunov S N , Toschakova Yu D , Yurkov V Yu 
Published: February 2021

Abstract
This paper is devoted to the mathematical calculation and experimental researching of ink apparatus using in printing machines. We show the existence of structuring process in ink boxes and the formation of so-called quasi-solid in the printing ink. Our geometric model is based on the mathematical problem of covering some planar domains by the set of circles. All circles belong to one-parameter family and it is a special feature of the problem. Using this model we get the method of calculation some optimal dimensions of passive activators using for destruction the quasi-solid. Calculations are based on experimental data and it is achieved by variation of several parameters. In this paper we describe the system with only one passive activator but there exist the opportunity to optimize the system with several ones. Software realization is not given in the paper but it is based on the algorithms that are described. Experimental data were received with using real equipments and materials of printing industry. Specifically, we investigated the generating of quasi-solids in the ink boxes and we got some results for using the passive activators.
Setting of the Dupin cyclide by three straight lines and sphere
Authors: Salkov N A 
Published: February 2021

Abstract
Over the past few years, interest in Dupin cyclides has re-emerged: they can be used both in mechanical engineering and in construction, for covering the spans of civil buildings and in temple architecture; the properties of the Dupin cyclide can be widely used in computer graphics. The article considers a method for setting of Dupin cyclides using three lines and a sphere, which greatly the possibilities for the construction of these surfaces, especially when it is necessary to cut compartments of a certain size from them and to dock them.
Methods of investigation and elimination of systematic errors in the realization of pseudo-random variables with heavy-tailed distributions
Authors: Zadorozhnyi V N , Zakharenkova T R , Pagano M 
Published: February 2021

Abstract
Shifts arising in generation of random variables, which are obtained by transformation of standard random numbers, with heavy-tailed distributions are investigated. The formula for calculation of deterministic moments shift for a random variable via a discretization spacing of used standard pseudo-random numbers is derived. The deterministic shift is calculated for a mean value of random variables that have the Pareto distribution and realized by the widely accepted inversion technique. The shift calculation results are verified and confirmed experimentally by means of the rapid Monte-Carlo technique – stratification method. By an example of the average queue length calculation, it is demonstrated how the shifts within distributions in queueing systems affect the queueing properties. The universal method for the realization of non-shifted random variables with heavy-tailed distributions, ARAND method, is developed and investigated. The method is based on the use of uniformly distributed between one and zero pseudo-random variables having a variable discretization spacing and represented in floating-point format.