bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tether system motion analysis of the various space debris’ anchor point positions
Authors: Faizullin L F , Pikalov R S 
Published: February 2021

Abstract
This study focuses on the dynamics of the tethered towing of the space debris. The motion of the system is reached in the force-free field and central gravitational field. A mathematical model is constructed. The space tug is modeled as a material point, the space debris as a solid body. The elastic tether connects objects to each other. In this study, we assumed that the anchor point of the tether to the space debris can be chosen arbitrarily. The aim of the work is to study the influence of the choice of the tether engagement point on the dynamics of the tug - space debris system.
Computational experiment for modeling shock-impulse technology of concrete mixtures forming
Authors: Titov S P , Thi Mong Thu Tran , Kondrashchenko V I 
Published: February 2021

Abstract
A mathematical model has been developed for modeling the technology of shock-impulse molding of concrete mixtures, according to the results of a computational experiment on which rational parameters of the rotor of the throwing device are determined in the form of two rotating cylinders with plates along their generatrices, intended for throwing the components of the concrete mixture onto the molded surface mechanically. A mathematical description of operation of such a device, interaction of individual particles with blades and their flight in the inter-rotor space up to the molding of the manufactured product is given. To stabilize the initial fractional composition of the aggregates, designs of rotors are proposed that provide portion capture of the concrete mixture or the use of the rubberized surface of rotors in the form of elastic tubular elements.
The change in the probability of aviation accidents “Collision of an aircraft with a bird” in accordance with of a change in the temperature cycle
Authors: Burmistrova V G , Butov A A , Volkov M A , Yavtushenko M S , Kostishko B M , Moskvicheva M G , Pchelkina Yu Z 
Published: February 2021

Abstract
This paper considers the possibility of predicting the most frequent aviation event “Collision of an aircraft with a bird”, depending on the seasonality near the airfield. A model for determining the probability of this event is proposed, where the “time of year” is identified by the predicted air temperature near the airfield in question and the problem of determining the accumulated probability is solved. We consider the first approximation in which events are assumed to be independent (these are complex ecological and ornithological conditions and flaws of airfield’s ornithological support). Due to the first approximation of independence, the paper provides a possible way to determine the probability of the event “Collision of an aircraft with a bird”. This method (in the form of a formula) determines the probability of intersection of events caused by hazard factors. The result of the simulation is the probability of long-term forecasting of the probability of an aviation incident due to an aircraft collision.
Mixed mode fracture in perfect plastic materials for plane stress conditions
Authors: Stepanova L V , Peksheva A A 
Published: February 2021

Abstract
In the study the asymptotic stress fields in the neighbourhood of the crack tip in perfectly plastic Mises materials under mixed mode loading for the full range of the mode mixities are presented. This objective is engendered by the necessity of considering all the values of the mixity parameter for the full range of the mode mixities for plane stress conditions to grasp stress tensor components behaviour in the vicinity of the crack tip as the mixity parameter is changing from 0 to 1. To gain a better understanding of the stress distributions all values of the mixity parameter to within 0.1 were considered and analyzed. The asymptotic solution to the statically determinate problem is obtained by the eigenfunction expansion method. Steady - state stress distributions for the full range of the mode mixities are found. The type of the mixed mode loading is controlled by the mixity parameter changing from zero for pure mode II loading to 1 for pure mode I loading. It is shown that the analytical solution is described by different relations in different sectors, the value of which is changing from 7 sectors to 5 sectors. At loadings close to pure mode II, seven sectors determine the asymptotic solution for the mixity parameter less than 0.39 and five sectors determine the solution for other values of the mixity parameter for plane stress conditions. The number of sectors depends on the mixity parameter. The angular stress distributions are not fully continuous and radial stresses are discontinuous for some values of the mixity parameter.
Further boundary conditions in heat conduction problems in multilayer structures
Authors: Trubitsyn K V , Mikheeva G V , Klebleev R M , Kurganova O Y 
Published: February 2021

Abstract
This paper presents an approximate analytical solution of the heat conduction problem for a two-layer plate under symmetric boundary conditions of the first kind. The solution was determined on the basis of the property of the parabolic heat transfer equation associated with an infinite velocity of heat propagation, by determining the accessory unknown function and accessory boundary conditions in the integral heat balance method.
Local coordinate systems are given in order to obtain the simplest possible coordinate system satisfying the matching conditions and boundary conditions for each separate layer. An accessory unknown function is the temperature change over time in the center of symmetry. The use of this function in the heat balance integral method allows for reduction in the solution of the initial partial differential equation to the integration of an ordinary differential equation with respect to the additional unknown function.
Further boundary conditions are defined in such a way that their satisfaction by an unknown solution is equivalent to the satisfaction of the equations at the boundary points. Studies have shown that the equation fulfillment at the boundaries leads to their fulfillment within the regions.
Application of molecular dynamics for modeling processes in microfluidic devices
Authors: Agafonov A N , Eremin A V , Milanina K I , Gavrilov V M 
Published: February 2021

Abstract
The article considers the possibility of using the molecular dynamics (MD) as part of multi-level models for describing processes in microfluidic devices. Much attention is paid to issues related to the use of MD to describe processes at a gas-solid interface.
Numerically stable algorithm for identification of linear dynamical systems by extended instrumental variables
Authors: Ivanov D V , Zhdanov A I 
Published: February 2021

Abstract
Instrumental variables are widely used to identify linear dynamical systems. The advantages of instrumental variables include low computational complexity, as well as the possibility of identification for different models of color noise. Often the method of instrumental variables leads to ill-conditioned problems, which significantly limits the application of this method. The paper proposes a solution to the problem of extended instrumental variables based on augmented normal equations. Test examples showed a high accuracy of the proposed approach.
The thermal conductivity Modeling taking in single crystals into account the anisotropy of their properties
Authors: Kh Badamshin I 
Published: February 2021

Abstract
For new materials, information on the thermal conductivity and propagation velocity of oscillation characteristics necessary for calculating the stress-strain state of the design elements is limited. In these conditions, there is a need for theoretical methods for calculating the thermophysical properties. The proposed theoretical methods based on forces of interatomic interaction calculation. The classical methods based on the hypothesis of continuity do not allow calculating the material thermophysical properties.
On the structure of the orthotropic 3D permeability tensor of an anisotropic porous body in heat and mass transfer problems
Authors: Ryazhskikh V I , Nikolenko A V , Konovalov D A 
Published: February 2021

Abstract
The structure of a 3D permeability tensor with orthotropic properties is proposed to describe various heat and mass transfer processes in anisotropic porous media. This structure of the permeability tensor has advantages over the monoclinic and triclinic because of the minimum number of elements to be determined, which greatly simplifies the formulation, conduct and processing of the corresponding experiments. In addition, the confirmation of the operability of such a structure opens up new opportunities for the artificial creation of porous materials with specified properties and the required anisotropy architecture on 3D printers. Using the Jacobians of rotations in the Cartesian reference system, the matrix of rotations is found as a result of successive multiplication of Jacobians by different angles around the axes of the base coordinate system. The final form of the tensor is identified as the product of the orthotropic tensor on the left and right by the turn matrix and the transposed turn matrix, respectively. This representation allowed us to calculate the inverse permeability tensor and synthesize a mathematical 3D model of Darcy-Brinkman type of unidirectional flow in a porous channel of rectangular cross-section on the example of hydrodynamic filtration of a Newtonian fluid. It is shown that such linearization does not level the property of anisotropy in a porous medium, while maintaining three-dimensionality.
Recovery of the hydrounit performance characteristics via a few observations
Authors: Kovartcev A , Nazarova A , Zakharchenko V 
Published: February 2021

Abstract
The performance characteristic of hydrounits is used very often in various control systems on hydro power plant for velocity control, power distribution, for displaying at different levels of automation pyramid for technicians, technologists, management and so on. As building of new HPP is very expensive, last years main investments in this sphere were made to reconstruction, modernization and increasing of efficiency of the existing HPPs. Before new or reconstructed hydrounit is put into industrial operation, it should pass a set of tests to check its operability at set parameters of safety operating conditions. In this case variety of hydrounit tests is significantly limited. Resulted from this fact there is a problem of the hydrounits performance characteristics recovery via a few observations. The present paper describes the hydrounit characteristics recovery method based on usage of limited number of experimental data. Results of examination of properties of the method offered are also described.
The use of the spatial-structural model of a video signal from the television scanistor in tasks of monitoring the geometric parameters of small objects
Authors: Arkhipov I O , Shelkovnikov Yu K , Meteleva A A 
Published: February 2021

Abstract
The paper proposes a video signal model for determining the size and coordinates of the light zone on a television scanistor. The key idea is to represent the profile of the light zone in the form of a vector of spatial and structural parameters that can localize the light zone and restore its width and illumination. The use of the spatial-structural model of the video signal allows expanding the scope of scanistor optoelectronic systems for monitoring the geometric parameters of small objects.
Analysis of the possibility of deterministic chaos occurrence during moving of an Earth remote sensing satellite with gyro dampers
Authors: Pankratov V M , Barulina M A , Golikov A V , Pankratova E V 
Published: February 2021

Abstract
The purpose of the work is the mathematical modeling and analysis of pitch oscillations of an Earth remote sensing satellite, in the point of view of the possibility of occurrence of deterministic chaos during the process of calming the natural vibrations relative to the satellite’s center of mass. A nonlinear mathematical model of oscillations of an Earth remote sensing satellite with floated gyrodampers with an integrated thermal control system based on Peltier thermopiles is constructed. According to the results of computer simulation by using the developed library of temperature perturbation models, it is shown that for some values of the parameters of the system under study, deterministic chaos can occur. Phase portraits of the transition of the satellite in pitch oscillation from regular to chaotic motions were constructed. Areas of deterministic chaos are created as functions of the parameters of systems with gyro dampers and the characteristics of external temperature and mechanical disturbances.
On a static solution to the contact interaction of a flexible rectangular in plane of a microshell with a rectangular in plane of microplate
Authors: Papkova I V 
Published: February 2021

Abstract
The mathematical model of the contact interaction of a flexible rectangular in plane of a spherical microshell and a flexible rectangular microplate is constructed. The material of the shell and plate is elastic isotropic and homogeneous. Kirchhoff hypotheses are taken into account. A system of nonlinear partial differential equations is derived from the Hamiltonian energy principle on the basis of a modified couple stress theory. The contact pressure function was determined according to the theory of B.Ya. Cantor. Contact interaction of sensitive elements of micromechanical sensors of inertial information in the form of a micro-shell and micro-plate is investigated. A micro-shell is affected by a static, uniformly distributed load. The static solution is determined by the establishment method. A new phenomenon related to the loss of stability is obtained.
Optimization the main thermodynamics parameters of the aviation turbofan engines with heat recovery in the aircraft system
Authors: Omar H H , Kuz’michev V S , Tkachenko A Y 
Published: February 2021

Abstract
Improving the fuel efficiency of aircraft engines is the main global trend of modern propulsion engineering. One of the promising ways to improve fuel efficiency is the use of complex thermodynamic cycles with heat recovery of exhaust gases. An important task in the design of engines with heat recovery is to select the main thermodynamic parameters process that ensures maximum efficiency of the engine in the aircraft system. The article presents the setting problem of optimization and selection of rational parameters of the working process of turbofan engines with heat recovery. Based on the developed method of multi-criteria optimization utilizing numerical simulations conducted and presented the results of optimization of parameters of the working process of turbofan engines with heat recovery in the system of aircraft according to criteria such as the total mass of the engine and fuel required for the flight, the specific fuel consumption of the aircraft on a ton per kilometre and the specific fuel consumption of engine (SFC). The developed mathematical model for calculating the mass of a compact heat exchanger presents to solve optimization problems at the stage of the conceptual design of the engine. The developed methods and models are implemented in the ASTRA program.
Order reduction for critical traveling wave problems
Authors: Shchepakina E 
Published: February 2021

Abstract
The paper deals with the order reduction for critical traveling wave problems. The specificity of such traveling waves is that they separate waves with qualitatively different behaviors. W e show how the application of the geometric theory of singular perturbations allows us to reduce the traveling wave problem for the original PDE system to the analysis the projection of the system onto its slow invariant manifold. W e illustrate this approach to the problem of finding the point-to-periodic traveling wave for the reaction-diffusion model.
Order reduction for problems with traveling wave solutions to reaction–diffusion systems
Authors: Shchepakina E , Tropkina E 
Published: February 2021

Abstract
The paper is devoted to the order reduction for traveling wave problems for reaction-diffusion systems. The use of the method of invariant manifolds of singularly perturbed systems allows us to replace the study of the traveling wave of the original PDE system with the analysis of their profiles in the ODE system with a lower order.
Modeling of the interaction of cylindrical bodies with complex surface properties
Authors: Kazakov K E 
Published: February 2021

Abstract
The axisymmetric contact problem of interaction between cylindrical bodies with complex surface properties (elastic properties or shapes) is described. For this problem, its mathematical model is constructed. It is mixed integral equation. An analytical solution for the problem of finding contact stresses under the bush is obtained. It allow one to make efficient calculations even when the coating nonuniformity and bush internal profile described by rapidly changing functions.
Latest results and future prospects of the pierre auger observatory
Authors: Miramonti Lino 
Published: February 2021

Abstract
The Pierre Auger Observatory is the largest observatory for the detection of ultra high energy cosmic rays (UHECRs). It allows a detailed measurement of the energy spectrum, the mass composition and the arrival directions of the primary cosmic rays with energies above 100 PeV. The data collected with the Pierre Auger Observatory show a suppression of the cosmic ray flux at energies above 40 EeV but the nature of this suppression is still unclear; according to theoretical prediction it could be caused by the interaction of cosmic rays with the CMB or by energy limitations of the cosmic rays sources. Another puzzle concerns the specific origin of UHECRs. Some indications can be obtained from studying the distribution of their arrival directions. Recently a dipole anisotropy has been observed which indicates that UHECRs have an extragalactic origin. I will present the recent results of the Pierre Auger Observatory about the energy spectrum, the mass composition and the arrival directions of UHECRs. I will also discuss the future prospects of the Observatory.
Hydrodynamical evolution and their light curves for a new GRB-Afterglow modal
Authors: Zouaoui E , Mebarki N 
Published: February 2021

Abstract
A model of a hydrodynamic evolution of an external shock produced by the deceleration of a relativistic jet ejected by a progenitor of the gamma ray burst is proposed and studied. The model shows new aspects and gives the most realistic description of the radiation energy produced by the fireball. The properties of the light curve of the GRB-Afterglows are also discussed.
The design of optimal reversible comparator circuit using new quantum gates
Authors: Slimani A , Benslama A 
Published: February 2021

Abstract
This paper presents a novel approach for designing reversible n-bit comparator based on new quantum gates. Their quantum equivalent implementations are also proposed. The design of comparator circuits is completed by using existing reversible gates and the above new reversible circuits. The comparative results are presented in terms of quantum cost, quantum delay and garbage outputs.
Study on the Correlation between OBF and Age Based on Analysis of Time Domain and Frequency Domain
Authors: Yu Jintao , Han Xiaowei 
Published: February 2021

Abstract
Many studies indicate that the old people are prone to high blood pressure with the age growing. Elevated blood pressure can lead to the changes of hemodynamic parameters in the blood circulation system, and then cause abnormal changes in the physiological activities of the endothelium, heart and so on. These Characteristic of physiological rhythm reflect the changes of ocular blood pressure and ocular blood flow signals. Thus, we could study on the correlation between ocular blood flow (OBF) and age by analyzing the variety of age on hemodynamic. The paper sets out to fully examine the time domain and frequency domain relationship between OBF and age. Time domain: the paper introduces the thigh cuff method to produce sudden drops in arterial blood pressure (ABP) and study the evolution of the immediate OBF response with LSFG. The LSFG (Laser Speckle Flow graph) allows for quantitative estimation of blood flow in the optic nerve head (ONH), and it is the only noninvasive method that allows sufficient temporal resolution to measure these rapid changes. The paper studies on the relationship between time-domain parameter Kr(L) (The slope of DAR descending curve), Kr(R) (The slope of DAR up curve), Tr(L) (The amount of time it takes to the maximal BF or BP decrease), Tr(R) (The amount of time it takes to the maximal BF or BP increase) and age, respectively. Kr(R), Kr(R), Tr(R) are shown significantly influenced by age changing. Frequency domain: in the case of without any factor, the harmonic content of the envelope waveform of the blood flow velocity in the ophthalmic artery is analyzed in aging and OBF. Cronbach-α reliabilities of the calculated frequency coefficient (FC) and frequency index (FI) are 0.91 and 0.92, respectively. The FI of the ophthalmic artery allows an assessment of the ocular circulation in consideration of age and OBF. The order the age, the smaller the FC, FI in OBF.
Research on Consumer Initial Trust Model Based on Internet of Things
Authors: Wang Ai-Ling , Li Lei-ming , Xu Guo-ling 
Published: February 2021

Abstract
With the rapid development of the Internet, consumers are getting more and more diversified information and information channels. Information channel and information content play a vital role in the initial trust of consumers. On the basis of receiving a certain amount of information and information valence, consumers are influenced by information channels to generate corresponding perceived value, thus generating and establishing initial trust. When the information channel is the customer side, the interaction between information quantity and information valence has the strongest regulating effect on perceived value. When the information channel is an enterprise, information quantity and information interaction have the weakest regulating effect on perceived value.
A Study on Polymerization Depolymerization Process of Multi-resolution Simulation Model
Authors: Wang Yaqi , Chen Yukun , Qu Qingjun 
Published: February 2021

Abstract
The future warfare system will become more complex, and the battlefield posture will be diversified, multi-resolution modeling technology is an effective method to solve the complex system simulation. How to perform model aggregation and deconvolution to support multi-resolution modeling is a difficult and important research content. To address this problem, on the basis of elaborating the requirements of multi-resolution modeling for combat simulation, the specific process of the model aggregation and depolymerization method is studied, and the system process of model aggregation and depolymerization for multi-resolution simulation is determined.