bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soliton surfaces for complex modified Korteweg–de Vries equation
Authors: Bauyrzhan Gulnur , Yesmakhanova Kuralay , Yerzhanov Koblandy , Ybyraiymova Sveta 
Published: December 2019

Abstract
In mathematics and physics, one of the main tasks is to relate differential geometry and non-linear differential equations, which means that the study of particular cases of subvarieties, curves, and surfaces are of great importance. Soliton surfaces associated with the integrable system play an essential role in many problems with the physical application. In this paper, we study the complex modi ed Korteweg de Vries (cmKdV) equation. It is well known that the cmKdV equation is a very important integrable equation. We present the relationship between an integrable system and soliton surfaces and namely Lax representation of the cmKdV equation was used to obtain the rst and second fundamental forms, surface area and curvature.
Optimal control synthesis for affine nonlinear dynamic systems
Authors: Bagdasaryan Armen 
Published: December 2019

Abstract
The problem of optimal control synthesis of complex nonlinear and multidimensional systems oriented on the building of integrated control systems with the adaptation and self-organization properties is of much current interest. The development of optimization methods employed in control problems demonstrated their effectiveness and has led to the construction of algorithms of approximate solution of optimization problems that significantly extends the class of control problems that can be set. In this work we consider a synthesis of optimal control for affine nonlinear system, in which a special emphasis is placed on the degenerate problems of optimal control. Our approach is based on the extension of the method of minimization of generalized work function by properly transforming the initial nondegenerate problem of optimal control into degenerate problem of optimal control synthesis. The search for the solution is based on the suboptimal strategy that includes the construction of minimizing sequences that converge interval-wise to the optimal solution of the initial problem. We obtain some optimality conditions as well as the necessary and sufficient conditions of existence of optimal solution.
HodgeRank as a quantitative tool in social representations theory
Authors: Pereira Ana L , Lunardi José T , Calçada Marcos , Viviane A Bagio 
Published: December 2019

Abstract
HodgeRank is a technique proposed by Jiang et al that provides a way for ranking data elements based on the relative importance that individuals associate to them. This technique has the advantage of working fine with incomplete and imbalanced data, besides providing a measure for the inconsistencies of the outcome. In this work we propose to use HodgeRank as a complementary quantitative tool for analysing the content and the structure of a Social Representation, in which data are spontaneous evocation of words or phrases by a group of individuals; such words or phrases are induced by a term which constitutes the object of the representation under study.
Econometric assessment of the world energy market impact on the incomes of the consolidated budget of Russia
Authors: Absalyamova S , Zulfakarova L , Ivanova N , Mukhametgalieva C 
Published: December 2019

Abstract
The article is devoted to the study of modern trends in energy resources megamarket. The results of the study reveal a system of factors affecting the production and consumption of energy resources in the global economy. The authors make a forecast of the development of traditional and alternative energy in the coming decades. The paper assess the degree of influence of the changing conjuncture of the world energy market on the Russian economy. The study shows the presence of high closeness of communication on the Chaddock scale and the direct linear dependence of Russia’s GDP at current prices on the volume of oil and gas revenues of the consolidated budget of the Russian Federation, confirmed by calculating the Pearson correlation coefficient. The article proposes a set of measures that reduce the dependence of the Russian budget on the world energy market.
Particle-based modeling of the mechanical behavior of porous fluid-saturated viscoelastic solids
Authors: Shilko E V , Dimaki A V , Popov V L 
Published: December 2019

Abstract
In the paper, we developed a macroscopic discrete element model of permeable fluid-saturated materials with solid skeleton characterized by viscoelastic rheological properties. The Biot’s linear model of poroelasticity was used as a mathematical basis for describing the mechanical interrelation between the solid skeleton and interstitial fluid. Using this model, we numerically studied the dependences of the effective Young’s modulus and strength of fluid-saturated viscoelastic materials on the loading rate, sample size and the mechanical parameters, which determine the relaxation time of the solid-phase skeleton and the time scale of redistribution of fluid in the pore space. We revealed two dimensionless control parameters that determine the dynamic values of the effective mechanical characteristics of the samples under compression loading. We obtained the general relations that describe the above-mentioned dependences in terms of the two proposed control parameters. These relations have a logistic nature and are described by sigmoid functions. The importance of the proposed empirical expressions is determined by the possibility of their application for predicting the mechanical response of fluid-saturated materials of different nature (bone tissue, rocks, porous materials with polymeric skeleton, including elastomers, etc.) under dynamic loading.
Numerical modeling of Liesegang structures formation process under an electric field influence
Authors: Kireev V , Shalabayeva B , Jaichibekov N , Nizamova A , Kozhabay Z 
Published: December 2019

Abstract
In the present paper the formation of Liesegang structures, i.e. the process of periodic deposition with the mutual diffusion of two reacting chemicals in the presence of an external constant electric field, is studied using numerical modeling. The mathematical model of the process consists of three differential equations of diffusion-reaction for the concentrations of the initial components and the resulting precipitate. The kinetics of sedimentation is described in accordance with the Ostwald’s supersaturation theory. The equations of the mathematical model in one-dimensional and two-dimensional statements were solved numerically using the control volume method using computer code written by the authors in the C ++ language. As a result of numerical simulation in the absence of an electric field, periodic structures were obtained formed of the precipitate, which qualitatively corresponds to the patterns observed in the experiments. It is shown that numerically obtained Liesegang rings satisfy the well-known laws: the ratio of the distances to neighbouring rings remains constant and there is a power dependence between the distances to the rings and the time of their formation. The influence of the ratio of the concentration of the starting substances and the electric field strength on the nature of the structures formed is investigated. It also has been shown that an increase in the electric field strength leads to an increase in the number of structures formed.
Micromagnetic simulation of thickness-dependent magnetization reversal processes in elongated iron nanodots
Authors: Sudsom D , Döpke C , Blachowicz T , Ehrmann A 
Published: December 2019

Abstract
Micromagnetic simulations were used to investigate magnetization reversal processes in elongated ferromagnetic nanodots, prepared by combining two half-circles with a rectangle. The micromagnetic simulation program OOMMF is based on dynamically solving the Landau-Lifshitz-Gilbert equation of motion. Material parameters were chosen as typical for Fe (iron). Lateral dimensions were in most simulations chosen as 730 nm x 133 nm, while the dot height was varied between 3 nm and 54 nm. For different in-plane angles of the external magnetic field, varying magnetization reversal processes were found with changing dot thickness, offering a possibility to tailor magnetic states by modifying the thickness of the nanodot.
Development of cognitive competences in physics in students of Biology
Authors: Escobar J H , García-Gómez L , González J D 
Published: December 2019

Abstract
A computational method that contributes to the development of cognitive competences, in students of biology of Magdalena University, is based on the use of a novel environment of virtual experiences of physical systems. This article investigates the level of learning achieved through the implementation of virtual laboratories that can be used by the user to work in web environments and mobile devices. Conceptual tests were administered to evaluate students’ competences before, during and after instruction. We present some perceptions and comments of the students regarding the virtual laboratories of Newtonian mechanics and we conclude on their effectiveness in the development of cognitive competences.
Study of the fundamental interactions in the bounded states of the systems: Earth-Moon, Proton-Electron (hydrogen atom), positronium (process e- e+→e- e+), and quarkonium, ( QQ)
Authors: Beltrán J R , Escobar J H , González J D 
Published: December 2019

Abstract
All The bound states of two particles such as the earth-moon system, bound by the gravitational interaction, proton-electron pe
− hydrogen atom, positron-electron (e
+
e
−) positronium linked by the electromagnetic interaction and quark-antiquark (

(

q

q
¯

)

) quarkonium linked by strong interaction, provide physicists with a natural laboratory to study these interactions. In this paper we review the classical theories formulated by Newton and relativist due to Einstein of gravitational interactions to study the earth-moon system. As regards the bound states (pe
−), (e
+
e
−) and (

(

q

q
¯

)

) we used Schrödinger equation to calculate the energy spectrum of these systems, as well as the Feynman diagrams at tree order to determine in some detail the Hamiltonian of these systems, known as Breit-Fermi potential. The similarities and differences between the hydrogen atom and the positronium are analyzed. The quarkonio is studied in the framework of the non-relativistic quark model (MQNR), heavy quark, where the relativistic effects are negligible, confronting the theoretical and experimental results to observe its validity.
Scientometric Study of Superconductivity Research in South America from 1980 to 2019
Authors: González J D , La Hoz J De , Beltrán J R 
Published: December 2019

Abstract
This paper presents the scientometric analysis of superconductivity research output in South America from 1980 to 2019 and compares it with Global output as reported in Web of Science. The study shows that superconductivity research in South America had a steep growth between 1980 and 2000, particularly an abrupt hike in 2005 that is noticeable followed by a more or less steady pattern thereafter up to 2019. South America superconductivity papers are analysed bibliometrically to indicate the authorship, collaboration pattern, to identify the major institutions and most relevant journals; apart from identifying the research field or application area of research in superconductivity.
Poincare decomposition theorems and the Lomov regularization method
Authors: Kachalov Vasily 
Published: December 2019

Abstract
An important stage in the development of the differential equations analytic theory was the Poincare decomposition theorems. They assert the existence and uniqueness of solutions of initial problems for normal systems of differential equations, which are analytically dependent on a small parameter, provided that the right-hand sides are functions analytic in this parameter. If the Cauchy problem is singularly perturbed, then, in the general case, the solution will not be analytic in a small parameter. Nevertheless, within the concept of the regularization method of S. A. Lomov, the conditions for the existence of so-called pseudo-analytic solutions were found.
Numerical and statistical modeling based investigation of the detection efficiency of high-spectral-resolution lidars at different laser radiation wavelengths
Authors: Evgenieva Tsvetina , Anguelov Vladimir , Gurdev Ljuan 
Published: December 2019

Abstract
In the present work, a numerical and statistical modeling approach is developed for estimating the operation efficiency of high-spectral-resolution lidars (HSRLs), when determining the atmospheric aerosol extinction profiles along the lidar line of sight (LOS) at different sensing (laser) radiation wavelengths from the UV, VIS and NIR spectral ranges. The efficiency estimation is based on numerical modeling of the lidar signal profile along the LOS and the corresponding profile of the signal-to-noise ratio (SNR) of its measurement. The optimally efficient wavelength (at certain distances along the LOS) is that ensuring maximum signal strength and SNR and, consequently, brighter and clearer lidar images of specific aerosol objects and background. The results about the optimum wavelengths obtained under different atmospheric-turbidity conditions (clear or hazy atmosphere), in the presence of cirrus clouds, are proved by statistical modeling and processing of realistic (noisy) lidar profiles and recovering the atmospheric extinction profiles along the LOS. It is shown that up to certain characteristic altitudes (that are lower at higher turbidity) the UV wavelengths are advantageous in the above sense. Above the mentioned altitudes, successively, first the VIS and then the NIR wavelengths become more efficient compared to the UV wavelengths.
Trajectory portraits for the two perturbed centrally symmetric systems of point vortices
Authors: Boyarintsev V. D. , Boyarintseva T.E. , Gvozdev N.P. , Kobzeva V.M. 
Published: December 2019

Abstract
We describe the types of motion for two centrally symmetric systems of point vortices (in one vortices are located in the corners of a regular hexagon, in the other – in the corners of a regular octagon), caused by spatially periodic perturbation: in which the vortices are in the corners of two regular triangles or two squares with a common center.
Development of combined search methods for efficiency indicator extreme in variation statement of forecasting tasks for determine characteristics of composite materials
Authors: Gusev E L , Bakulin V N , Chernykh V D 
Published: December 2019

Abstract
Modified search methods for global extreme of multiparameter functions are studied, considering the structural features of efficiency criteria used in problems of forecasting residual life and durability of structures made of composite polymeric materials. Comparative and qualitative studies have been carried out and methods have been developed to select the most promising areas of search for the absolute minimum of the studied performance indicators in refined variation formulation of inverse problems of forecasting residual life of composites.
About orientational instability in nematic liquid crystal films
Authors: Kalugin A G , Pavlov D V 
Published: December 2019

Abstract
In the presented work the role of the surfacelike (splay-bend) elastic constant in the Frank’s energy of nematic liquid crystals for orientational instability in the thin nematic films is considered. It is shown that nontrivial periodical perturbations exist in the nematic film with undisturbed planar director orientation in case of sufficiently large value of splay-bend constant. For these solutions the relations between splay-bend constant, another Frank’s constants and layer thickness are received and studied. These correlations allow us to make new explanation for certain experimental effects and to present method for surfacelike constant value measurement.
Aeroelastic stability of a shell supported by a cylinder with a hole of linearly varying radius
Authors: Konopelchev M A , Bakulin V N , Ya Nedbai A 
Published: December 2019

Abstract
The aeroelastic stability of a shell supported by an elastic cylinder of varying thickness with the outer surface exposed to supersonic gas flow is studied. The supporting cylinder is considered as an elastic foundation, whose bedding value is determined from the equations of the three-dimensional theory of elasticity. The solution is obtained by the BubnovGalerkin method in the form of a trigonometric series in the axial coordinate. The characteristic equation is approximated by the Lagrange polynomial, whose stability is investigated with the use of the Routh-Hurwitz criterion. The dependences of the critical flow velocity on the length of the cylinder section with the tapered hole are shown for various values of the axial force, the damping decrement, and the shell thickness.
Model Estimates of Circulating Flow around Objects in the Marine Medium and Atmosphere
Authors: Korchagin N.N , Vladimirov I.Yu 
Published: December 2019

Abstract
Model studies of force action on streamlined fragments of technical structures by a stratified sea current have been carried out. Analytical expressions are obtained for the hydrodynamic load on a point dipole during its circulation flow around a two-layer fluid flow of finite depth. The dependences of the wave resistance and the lifting force on the velocity of the current and circulation are investigated. It is shown that taking into account the velocity circulation can significantly affect the force effect on the dipole. The effect of a sharp (reversible) change in the direction of lift in a relatively narrow range of the flow velocity of a pipeline fragment simulated by a dipole has been found. The effect can also appear when moving self-propelled underwater objects and aircraft in the atmosphere.
Non-uniqueness of transonic flow in an intake-type channel
Authors: Kuzmin A. 
Published: December 2019

Abstract
The two-dimensional turbulent airflow in a 9-degrees-bent channel is studied numerically. Inner surfaces of the top and bottom walls are parallel to each other upstream and downstream of the bend. The free stream is supersonic, whereas the flow is subsonic at the channel exit. Solutions of the Reynolds-averaged Navier-Stokes equations are obtained with a finite-volume solver using the Spalart-Allmaras and Shear Stress Transport k −! turbulence models. The solutions reveal a flow hysteresis and non-uniqueness in considerable bands of the free-stream Mach number, angle of attack, and exit pressure. At the endpoints of the bands, there are abrupt changes of the shock wave system. The non-uniqueness admits different losses of the total pressure, which may cause different trusts of an air breathing engine.
The problem of suspension injection into a porous medium within a two-velocity model of deep bed filtration
Authors: Leontiev N E 
Published: December 2019

Abstract
We consider flows of a suspension through a porous medium with account of the deposition of the suspended particles onto the internal surface of a porous matrix (deep bed filtration). The velocities of the suspended particles and the carrier fluid are plausibly supposed to differ by a known factor that depends on the suspension concentration. We present analytical and numerical solutions to the problem of suspension injection into a porous sample. The main qualitative result of the investigation is that — under certain circumstances — the smooth solutions (i.e., the ones that do not, in contrast to usual assumptions, involve concentration jumps) to the problem may exist. This feature may be of use for experimental data interpretation.
The effect of an additional air inlet in the hot outlet area on the overall effectiveness of a vortex tube
Authors: Privalov L Y , Mikhaylenko C I 
Published: December 2019

Abstract
In this paper the modification of a vortex tube is shown. The feature of this vortex tube is that it has an additional air inlet in the hot outlet area along the tube axis designed to redistribute air consumption between cold and hot outlets. Computational experiments are done in openFOAM toolbox using sonicFoam solver. In order to increase computational speed the mesh is being decomposed into equal parts, which allows for the parallel run using MPI on a single computer. The results of the experiment show temperature values and air consumption on the corresponding outlets in relation to the change of the vortex tube length. A conclusion about the effective vortex tube length is made.
On a theorem of impulse and energy to determine parameters of the electric jet engine KA
Authors: Sidnyaev Nikolay 
Published: December 2019

Abstract
The report presents the modern physical principles of acceleration of charged particles and plasma in electric and magnetic fields, which are the basis for the classification of electric rocket engines. It is shown that for reactive means of correction of orbit parameters the lifetime depends to a greater extent on the reserves of the working fluid and the corresponding thrust and energy for the propulsion system. It is postulated that the special value of the determination of pulses and energy for electric propulsion (ERD) is that their application makes it possible to obtain an idea of these phenomena on the boundary surface of a certain area, without knowledge of the individual phenomena occurring within the ERD. That is, often in cases where the differential equations of plasma flow can not be composed or at least can not be integrated, the theory of pulses or energy makes it possible to know the nature of the movement in its General features. It is convincingly proved that the theorems of impulses and energy are a convenient means for checking the correctness of the results, including experimental ones.
Estimation of maximum water levels during spring flood on Lena river parts using artificial neural networks
Authors: Struchkova G. P. , Kapitonova T. A. , Timofeeva V. V. , Nogovitsyn D.D. 
Published: December 2019

Abstract
The Republic of Sakha (Yakutia) possessing a vast territory located in various climatic zones and a developed network of water bodies is exposed to a wide range of natural emergency situations. Among them, spring-summer floods are the most frequent and bringing enormous damage, causing inundations of vast areas and national economy objects, which determines relevance of development and improvement of flood forecast methods for implementation of timely measures to prevent and reduce an inundation risk.
Artificial neural networks have proven their effectiveness in solving various forecast problems, especially when using statistical data. In particular, usage of a neural network approach based on the forecast of a time series from previous values gives good results. The artificial neural networks, unlike statistical methods of analysis, are based on parallel data processing, have an ability of self-learning and recognition of nonlinear relationships between input and output data sets. A choice of parts of the Lena river to predict maximum water levels during the floods was determined based on locations of potentially hazardous objects, the inundation of which can cause the considerable material damage. On the basis of the hydrological data obtained during 70 years, the neural network models are obtained, which make it possible to predict flood hazards from the spring floods, two variants of the transformed initial data are considered and different network structures are compared. Relative errors of the forecasts obtained during the work vary considerably (7–20%), which indicates necessity for the processing of the initial data and careful selection of the structure.