bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geometric modeling and study of properties of surfaces equidistant to two spheres
Authors: Vyshnepolsky V I , Kadykova N S , Peh D S 
Published: March 2022

Abstract
The paper considers the geometric locus of points equidistant to two spheres of different diameters. If these spheres are concentric, the sought multitude constitutes a single surface – a sphere of diameter equal to arithmetic mean of the diameters of the given spheres. In other cases the geometric locus of points equidistant to two spheres of different diameters constitutes two surfaces. In case the spheres intersect, are tangent or distant to each other, the first of these surfaces is a two-sheet hyperboloid of revolution that degenerates into a plane in case the spheres are equal. In case the spheres intersect, the second of the surfaces is an ellipsoid of revolution that degenerates into a straight line if the spheres are tangent to each other. In the case of distant spheres, the second of the surfaces is a two-sheet hyperboloid of revolution. In case the spheres contain one another, the sough geometric locus constitutes two co-axial co-focused ellipsoids of revolution. The equations defining the mentioned surfaces are presented. The regularities in shape and location of these surfaces were studied; the formulas for the major and the minor axes of the ellipsoids and the vertices of the two-sheet hyperboloids of revolution were derived.
Construction of a window function for estimating the parameters of sinusoidal signals with non-harmonic frequencies
Authors: Altman E A , Vaseeva T V 
Published: March 2022

Abstract
Discrete Fourier Transform (DFT) allows you to determine the discrete spectrum of a signal. Due to the presence of its high-speed implementation, called Fast Fourier Transform (FFT), this transform is widely used in digital signal processing (DSP). Most DSP tasks that deal with analogy signal and spectrum adapt the DFT to find the signal spectrum between harmonics. One of the most commonly used ways of such adaptation – the use of window functions. The analysis of standard window functions (Kaiser, etc.) showed that their direct application to solving the problem of estimating the parameters (frequency, amplitude, and phase) of nonharmonic sinusoidal components of signals leads both to the need for additional corrections of the estimation results and to additional errors in determining the phase of the signal. The paper proposes a method that allows building a window function without the indicated drawbacks based on standard window functions. The essence of the method is to transform the standard window function so that its spectrum does not contain imaginary components, and the amplitude of the fundamental harmonic would be equal to 1. The results of modeling the proposed method on the example of the Kaiser window showed that the phase estimate of the nonharmonic components of the spectrum using the obtained window function, in contrast to the estimate using standard window functions, is not displaced.
Image processing for automatic road inventory
Authors: Belim S V , Khiryanov E V , Kvashnina P A , Ostrinskaya L I 
Published: March 2022

Abstract
Road image analysis is an important task for automatic road inventory. The determination geometric dimensions for the road and the identification road objects are subprocess of constructing a road digital image. In this article, two algorithms for solving different subtasks of automatic road image inventory are proposed. The first algorithm identifies road signs. A convolutional artificial neural network is used in this algorithm. The training set for the neural network is prepared. A computer experiment to determine the recognition effectiveness of road signs has been conducted. The second algorithm defines the edges of the pavement. The algorithm consists five stages. The edges of the road are modeled as straight lines. The result allows you to automatically determine the width of the road.
Development of a medical expert system: disease staging by a fuzzy classifier
Authors: Serobabov A S , Denisova L A 
Published: March 2022

Abstract
The article considers an approach to the processing and analysis of biomedical data from clinical examination. An automated diagnosis system is presented to be applied in liver disease diagnosis by the results of the initial examination of patients using a classifier based on fuzzy inference. The research is carried out by modeling the proposed system in the environment MATLAB FuzzyLogic. The regularities are revealed making it possible to normalize the results of laboratory tests depending on gender characteristics and to increase the percentage of correctly determined disease stages.
Recognition of the MNIST dataset with defective rows
Authors: Shevlyakov A N , Berezin A A 
Published: March 2022

Abstract
One of the well-known classification problems in machine learning is the problem of recognizing handwritten numbers. This task is solved, since there are different neural networks that determine with fairly high accuracy which number is shown in the picture. In this paper, we will consider the recognition of handwritten digits subjected to certain deformations.
A Cascadic Multigrid Algorithm on the Shishkin Mesh for a Singularly Perturbed Elliptic Problem with regular layers
Authors: Tikhovskaya S V 
Published: March 2022

Abstract
A two-dimensional linear elliptic equation with regular boundary layers is considered in the unit square. It is solved by using an upwind difference scheme on the Shishkin mesh which converges uniformly with respect to a small perturbation parameter. The scheme is resolved based on an iterative method. It is known that the application of multigrid methods leads to essential reduction of arithmetical operations amount. Earlier we investigated the cascadic two-grid method with the application of Richardson extrapolation to increase accuracy of the difference scheme by an order uniform with respect to a perturbation parameter, using an interpolation formula uniform with respect to a perturbation parameter. In this paper a cascadic multigrid algorithm of the same structure is studied. We construct an extrapolation of initial guess using numerical solutions on two coarse meshes to reduce the arithmetical operations amount. The application of the Richardson extrapolation method based on numerical solutions on the last three meshes leads to increase accuracy of the difference scheme by two orders uniformly with respect to a perturbation parameter. We compare the proposed cascadic multigrid method with a multigrid method with V-cycle. The results of some numerical experiments are discussed.
Designing an information system for the electronic document management of a university: automatic classification of documents
Authors: Tkachenko A L , Denisova L A 
Published: March 2022

Abstract
To ensure the effective functioning of the university educational environment, document flow processes automation, which includes the task of documents automatic classification, is of great importance. The article considers the task of classifying university documents by machine learning methods in order to improve the quality of classification. Documents preprocessing was carried out, which made it possible to distinguish significant words in documents, due to which the accuracy of documents classification increased. Described are methods of extracting features from text TF and TF-IDF, which determine keywords by words frequency included in document. A modification of the TF-IDF method is proposed, which consists in calculating the words importance depending on their part of speech. This made it possible to improve the classification quality by highlighting only important and significant words in documents. Suggested is a classification algorithm using a method of support vectors to reduce the documents number involved in classification and a method of k-nearest neighbor for classification. The advantage of this algorithm over the described analogues is shown, which is expressed in the number of mistakenly classified documents decrease.
Approaches to constructing two-dimensional interpolation formulas in the presence of boundary layers
Authors: Zadorin A I 
Published: March 2022

Abstract
An overview of approaches to the construction of two-dimensional interpolation formulas for a function of two variables with large gradients in the boundary layer regions is given. The problem is that the use of polynomial interpolation formulas on a uniform grid can lead to errors of the order of O(1). It is shown that the use of polynomial interpolation formulas on the Shishkin and Bakhvalov grids leads to the fact that the error becomes uniform in a small parameter. More accurate results are obtained by using the Bakhvalov grid. It is shown that on a uniform grid it is possible to successfully apply interpolation formulas that are exact on the singular components responsible for large function gradients in boundary layers. Numerical results are given.
Generalization of the Fourier Problem on Fluctuations in the Temperature of the Earth’s Crust
Authors: Afanas’ev Anatoliy , Bakhracheva Yulia 
Published: March 2022

Abstract
The problem of asymptotic fluctuations of temperature and moisture content in a half-space is solved by the method of complex amplitudes. The material filling the half-space consists of a solid base (capillary-porous body) and water. The well-known Fourier solution for temperature fluctuations in half-space in the absence of moisture and under the boundary conditions of heat exchange of the first kind is generalized to the case of a wet material under the boundary conditions of Newton for temperature and Dalton for moisture content. The results of the work can be used in geocryology to model seasonal fluctuations in the thermophysical characteristics of frozen rocks and soils.
Development and research of an induction heating system for a long pipeline
Authors: Aflyatunov R R , Khazieva R T , Vasilyev P I 
Published: March 2022

Abstract
The authors proposed an induction heating system for an extended pipeline, which implements the technology of local-associated heating, using the methods of functional integration. The authors carried out a study of the technology of local-associated thermal effect on an extended pipeline. We have developed a technical solution for a system of local-associated induction heating of a long pipeline using functional integration methods. We also developed a computer model of the system in the ELCUT 6.4 software package. The authors evaluated the efficiency of the heating process and obtained the characteristics of the magnetic field of the system as a result of modeling. We have solved a thermal problem that demonstrates the efficiency of the local heating technology.
Numerical simulation of moisture extraction under the influence of an acousto-convective flow from a thin cavern
Authors: Bedarev I A , Zhilin A A , Lavruk S A , Trushlyakov V I 
Published: March 2022

Abstract
With using the mechanics of multiphase media, the process of extraction of moisture from a dead pore is considered. The study was carried out by numerical simulation. Two-dimensional approach of interaction of the air flow with droplets without taking into account the processes of heat and mass transfer was considered.
Justification of parameters of the process of injecting compressed air into the piston air spring in the boom machine working equipment
Authors: Boyarkina I V , Boyarkin G N 
Published: March 2022

Abstract
While lifting a payload, boom machines perform a useless job to overcome gravitational forces of the working equipment gravity force. The piston spring, injected with compressed air to a pressure of pw
=10-15 MPa, ensures balancing gravitational forces of gravity during vertical movements and eliminates the indicated disadvantage. The piston air spring, independently mounted in the boom machine working equipment, represents an energy saving unit. A detailed analysis of physical processes of obtaining high-pressure compressed air for the injection into the air spring has been conducted, new solutions have been obtained, connected with the technology of air compression to high pressure, satisfying definite design requirements.
The design and technological provision of strength and wear resistance of aeroponic installation elements
Authors: Derkach V V , Churankin V G , Sevoyan V A , Kirgizova I V 
Published: March 2022

Abstract
The use of modern resource and energy-saving technologies in multifactor technological processes is a promising direction that allows improving the design and technological support of the manufacturing sector in most developed countries. The use of an electrochemical installation - aeroponic installation with automatic control system in industrial processes allows to reduce the consumption of the working solution. It is a more energy efficient process compared to traditional production technologies. The article describes the results of the development and creation of an automatic control system for technological processes in an aeroponic installation. The results of research on ensuring the strength and wear resistance of the elements of the system for supplying the working solution in the form of an aerosol using nozzles are presented.
Development and investigation of a supercapacitor based on an aqueous electrolyte
Authors: Fedyanin V V , Fedorov V K 
Published: March 2022

Abstract
The article is devoted to the development and research of a supercapacitor based on an aqueous electrolyte. The review of the current state in the field of energy storage is carried out. The processes occurring in the supercapacitor are considered. Sheets of paper with different carbon concentrations have been created. The design of the housing has been developed with the possibility of replacing the plates and electrolyte. This is an advantage in the process of conducting experiments. According to the results of the study, a prototype supercapacitor based on NaCl electrolyte with a capacity of 9F and a maximum output voltage of 1.2 V is presented.
Experimental studies of thermodynamic combustion processes of combustible demonstrators
Authors: Iordan Yu 
Published: March 2022

Abstract
The description of experimental benches for combustion of demonstration elements of material samples - combustion demonstrators (CD) is given. CD for investigating thermodynamic processes during combustion on experimental benches are developed. The results of experimental studies of combustion of CD made of different materials (existing and synthesized) are presented. A new direction of research is formulated - the development of combustible materials and structures made of them, providing the specified characteristics at all stages of operation.
Justifying calculations of people warning and evacuation algorithms in case of fire in accordance with its source location variants and combustion development dynamic
Authors: Khrapskii S F , Bedrina E A 
Published: March 2022

Abstract
Modern warning and people evacuation management systems in case of fire are able to implement different notification options (with a start evacuation delay) and different people groups routing, which reduces their flows density and the critical congestions formation probability on the evacuation routes. For these systems potential technical capabilities practical realization, warning and evacuation algorithms are required in accordance with the fire source location, the combustion development dynamic, the characteristic parameters of the object and the evacuating people. Such algorithms generation is possible on the basis of information about the current values and fire hazards increase dynamic in the premises and on the evacuation routes. The necessary information can be obtained as a result of numerical studies using software tools that implement mathematical models of heat and mass transfer and gas dynamic processes, as well as the evacuating people flows movement processes in case of fire. One of the algorithms examples for alerting and evacuating people for the educational institution building is presented. The calculated data make it possible to predict and evaluate the people safe evacuation fundamental possibility in case of fire and to propose space-planning, technical and organizational solutions and measures for its successful implementation.
Ductile barrier deformation mechanism
Authors: Proskuryakov N E , Lopa I V , Pasko A N 
Published: March 2022

Abstract
Impact loading of a barrier from ductile material is considered. It is postulated that deformation process can be modeled two independent interfaced tasks: deformation of a barrier as plate of final thickness from elastic and viscous-plastic material the hard puncher and evaluation of energy loss of the puncher on material deformation under it and overcoming force of front resistance. It is shown that on the one hand, losses of energy of the puncher on barrier material deformation by longitudinal waves of tension both on formation, and on a stopper cut, and with another are most significant, process of promotion of the created stopper is longest and determines generally time of breaking through the barrier.
Determination of the strain rate effect in electromagnetic forming processes
Authors: Proskuryakov N E , Lopa I V , Zverev I V 
Published: March 2022

Abstract
Effect of strain rate, quantity of plastic deformation and temperature of material on characteristics of material at electromagnetic forming is considered. It is shown that strength characteristics increase with growth of strain rate, and the plasticity increases with an increase in the value of plastic deformation and temperature. The variant of writing of the constitutive equation considering these changes is offered, and its use in calculations can significantly increase efficiency of calculations of operations of electromagnetic forming.
Dynamic characteristics modeling of rotary platform installed on board of a small spacecraft
Authors: Sedelnikov A V , Taneeva A S 
Published: March 2022

Abstract
The paper analyzes the capabilities of an automatic rotary platform of the "Flyuger" type to reduce micro-accelerations in a protected area when it is installed on a small spacecraft of the "Aist-2" type. The micro-accelerations field of the working volume of scientific equipment of the "Growth installation" type has been modeled. The comparison with flight test data is made. The results of the work can be used in the design of small technological spacecraft.
On application of rubber-metal seismic isolating supports of a ball tank under seismic load
Authors: Sergaeva M Yu , Lyubykh A M 
Published: March 2022

Abstract
This article considers the possibility of using seismic supports in seismic protection systems for ball tanks for storing liquefied hydrocarbon gases in seismically unstable operating conditions. Attention is paid to the study of support structures, which include rubber-metal vibration isolators. Based on the theory of long-term strength, the issues of the operability of rubber-metal seismic-insulating supports (RMSS) are considered. The use of RMSS reduces seismic loads in the supports of the tank by 1.5-2.0 times. At the same time, the analysis of the stress-strain state (SSS) of the tank body showed that the structural elements retain their operational characteristics under seismic load and meet the strength conditions in accordance with the requirements of the current standard technical documentation.
Methodology improvement for assessing the traction electric motors collector’s surface
Authors: Shkodun P K 
Published: March 2022

Abstract
The results of experimental studies of the rolling stock traction electric motors collector profile are presented. A technique is shown for combining collector’s profilograms in the cold and hot state for non-synchronized values of the origin. A new diagnostic parameter is proposed for assessing the state of the traction electric motors collector profile - the root-mean-square value of the difference in the relative heights of the collector plates in cold and hot states. The changes comparison results in the proposed diagnostic parameter for traction electric motors after repair in a locomotive repair depot are presented. The analysis of the influence of the collector formation on the state of the rolling stock traction electric motors collector profile is carried out. It is shown, that the change in the collector profile can be caused by two reasons - poor-quality forming, as well as poor-quality repairs.
Investigation of the dynamic stability of pressure regulators when taking into account the inertial forces of the hydraulic fluid flow
Authors: Syrkin V V , Galuza Yu F , Abramova I A , Treyer V A 
Published: March 2022

Abstract
The dynamic stability of pressure regulators in hydraulic systems of technological machines is considered, in which additional hydrodynamic forces arise in unsteady modes. The magnitude of these hydrodynamic forces is determined mainly by the first derivative of the flow rate through the throttle slot of the regulator in time. Experimental studies of pressure regulators have shown that hydrodynamic forces, depending on the switching scheme and the design dimensions of these devices, can affect their stability in various ways.
Determination of the parameters of the microwave ion thruster by the calorimetric method
Authors: Vavilov I S , Fedyanin V V , Yachmenev P S , Zharikov K I , Lukyanchik A I , Stepen’ P V 
Published: March 2022

Abstract
The paper presents the results of research to determine the dynamic component of the force of the jet stream of a microwave ion engine. The dynamic component was determined by an adiabatic calorimeter based on a heat flux density sensor. Experimental studies have shown that with a working fluid consumption (nitrogen) from 0.01 to 0.08 mg/s, the thrust of the micro-motor was from 1.45 to 13 μN. The calorimetric method gives inflated thrust values presumably due to ohmic heating in a DC glow discharge.
Determination of the thrust of an ion thruster by the resonant aerodynamic method (RAM-method)
Authors: Vavilov I S , Yachmenev P S , Fedyanin V V , Stepen’ P V , Lukyanchik A I , Zharikov K I 
Published: March 2022

Abstract
This paper presents the results of an experimental study of the jet thrust of ionized nitrogen flowing from the working chamber of an experimental sample of an accelerator ion thruster into a vacuum space. The resonant aerodynamic method (RAM-method) was chosen as the main research method. A method for determining low thrust and the design of a stand for implementing the RAM- method are proposed. The object of research is a prototype of an accelerator two-gap ion thruster with a solid-state microwave plasma generator and a toroidal resonator. The study showed that a 2.5 W microwave generator together with a 2.5 W accelerating potential difference voltage source at a nitrogen consumption of 0.1 mg/s creates an ion jet, the speed of which reaches 100 km/s. The current of the ion jet was 5.5-6 μA. The jet thrust was 0.141-0.188 μN.