bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contributing factors in academic performance and troubles associated with teaching in areas of physics in engineering students
Authors: Garzón-Agudelo P A , Palacios-Alvarado W , Medina-Delgado B 
Published: December 2020

Abstract
Learning processes are affected by a series of factors, both individual students and the institutional environment in which they develop. The present work is developed under the context of learning processes in areas of physics in engineering students, belonging to the academic program of technology in industrial processes, considering the socio-demographic and academic variables that affect students and that in turn affect student dropout. Data collection instruments were applied to a population group of 90 students, allowing to propose strategic scenarios that would contribute to improve the quality of academic processes and students’ skills in the study of mechanical and electromagnetic physics. It was determined that the role played by teachers and the methodology in which they teach their students, the physical conditions and teaching methods directly affect the effectiveness of learning and academic performance. It was also demonstrated that the lack of prior knowledge in the fundamentals of logic-mathematics and basic physics are determining aspects in the failure and repetition of the subjects.
Measurement of emotional variables through a brain-computer interface in the interaction with books with augmented reality in higher education
Authors: Rojas-Contreras M , Peña-Cortés C A , Cañas-Rodríguez S M 
Published: December 2020

Abstract
This article aims to describe the process of measuring mental state variables through a brain-computer interface in the interaction of humans with books with augmented reality; specifically, it seeks to analyze the variables commitment, stress, interest, relaxation, excitement, concentration in the interaction of students with a book with augmented reality compared with the measurement of the same variables when reading a traditional text. For the process of measuring emotional signals, two texts were designed for the data structure subject of the systems engineering program, the first in traditional format and the second with augmented reality applications. Subsequently, the mental state measures were taken through the brain-computer interface to the sample of students of the subject interacting with the traditional book and the book with augmented reality. Finally, through the interface software application, the results of the variables of each student interacting with the mentioned texts were downloaded and comparatively analyzed. Through comparative analysis, it is shown that the variable of mental state interest increases in the interaction of higher education students with books with augmented reality compared to reading a traditional text. Brain-computer interface systems have become an effective strategy for the measurement of emotional variables in the incorporation of emerging technologies such as augmented reality into teaching-learning processes in higher education.
Affective and interactive suitability indicators: an experience in physics from the onto-semiotic approach
Authors: Rincón Leal O L , Jaimes Fonseca L K , Fonseca Palacios R A 
Published: December 2020

AbstractThe purpose of this research was to propose theoretical elements for the description of the students’ attitudes in the teaching of differential calculus and its applications to physics from the onto-semiotic approach in the affective and interactional suitability. The design of this research with a complementary approach of qualitative and quantitative methods, with predominance of the first one, under the interpretative paradigm. The field modality and a quasi-experimental design to evaluate the applicability of the concepts of differential calculus. The collection techniques were: first, the semi-structured interview, in order to guarantee the depth and density of the information so that it converges in an emerging system of meanings and categories; second, the application of a questionnaire to evaluate the cognitive capacity of students under the onto-semiotic and traditional approach; third, observation through surveys. The findings lead to an instructional process through which mathematical concepts are taught efficiently, the student’s role is valued as being assertive, autonomous, and responsible, while the teacher contributes to the development of emotional support by increasing the student’s motivation, self-confidence, and interest in learning mathematics.
A method to solve the heat transfer problem for laminar flow of Phan-Tien-Tanner fluid in a flat channel
Authors: Kadyirov A I , Vachagina E K 
Published: December 2020

Abstract
The paper presents a solution to the heat transfer problem for a flow of a four-mode viscoelastic linear Phan-Tien Tanner fluid in flat channels at a constant wall temperature. A special feature of this solution is the parametric representation of dependence of an axial velocity and temperature on coordinates. To obtain a solution to the energy transfer equation, we used the method of separating variables and decomposing the sought-for function into series by parameter. For a specific liquid, the profiles of dimensionless velocity and distribution of dimensionless temperature, Nusselt numbers, and other heat transfer characteristics for various Weissenberg numbers are presented.
Tornado-like vortices behind a cylinder in a channel at moderate Reynolds numbers
Authors: Molochnikov V M , Mazo A B , Kalinin E I , Paereliy A A , Dushina O A , Kluev M A 
Published: December 2020

Abstract
Experiments and direct numerical simulation were employed to study the near wake of a circular cylinder in a cross flow in a rectangular channel. The gap between the cylinder and the channel wall was varied. Moderate Reynolds numbers were considered. The analysis of experimental results in combination with numerical simulation revealed the common patterns in the vortical structure of flow behind the cylinder, namely the tornado-like vortices formed in the region where the cylinder was attached to the sidewalls of the channel. The effect of the cylinder location on the onset of Karman vortex street was estimated. The formation mechanism of tornado-like vortices was described.
RANS and LES simulation of separated flow in a flat channel with a back-facing step
Authors: Terekhov V V , Barsukov A V , Terekhov V I 
Published: December 2020

Abstract
The results of numerical calculation by the RANS and LES methods of turbulent separated flow in a flat channel with a back-facing step are presented. The calculation was carried out for Reynolds number Re = 5000, determined by the average mass velocity and the step height. The effect of vortex generators in the form of a transverse rib on the heat transfer intensity has been studied, and the data obtained are compared with experiment.
Experimental comparative research of convective heat transfer enhancement in channels
Authors: Frantsuzov M S , Ilchenko M A , Koroleva A P 
Published: December 2020

Abstract
This article presents the results of a comparative-experimental research of various methods to intensify heat transfer in the channel. Four different methods of heat exchange enhancement are considered: twisted tape, wire spiral, joint intensifier made of wire tape and twisted spiral, and acoustic method of intensification. The thermal and hydraulic characteristics of various methods of heat exchange intensification are experimentally investigated, and the efficiency of heat exchange intensification is determined. The thermal and hydraulic characteristics of a smooth channel without intensification obtained experimentally under the same conditions were used as a reference. In the course of the comparative analysis of the considered methods of intensification, the most effective ones are found in the range of changes in the Reynolds number from 10000 to 60000. The presented data can be used in the design of heat exchangers.
Superheated metastable atomized water plume diagnostics peculiarities in confusor-diffuser nozzles; atomizaton process: dimensionless treatment
Authors: Zalkind V I , Zeigarnik Yu A , Nizovskiy V L , Nizovskiy L V , Schigel S S 
Published: December 2020

Abstract
Micron mode mass fraction
ε
determination method was tested for dense superheated water atomization plumes based on measurement attenuation coefficients of primary laser radiation. The initial water temperature in experiments was 200 and 240°C. The mass fraction of micron mode
ε
was determined using Bugger-Lambert equation and Mi theory. The comparison with previous data, which were obtained by scattering indicatrix analysis, was done. In terms of development of dimensionless treatment of experimental data on superheated water spray, the parameter expression for the transition to predominating role of nucleation in superheated water atomization in confusor-diffuser nozzles was revised the base of critical bubble formation.
Research of mechanisms of interaction of melt and coolant by means of small-sized experiments with solid and liquid metal samples
Authors: Ivochkin Yu P , Ismailov A M , Kubrikov K G , Teplyakov I O 
Published: December 2020

Abstract
Several basic fragmentation hypotheses described in the literature for the case of fine-scale spontaneous vapor explosion, when single hot drops are falling in the coolant, are analyzed. It is shown that all of them, depending on the experimental conditions, describe the real physical phenomena. It is highlighted, that the process of fragmentation during the spontaneous vapor explosion is directly connected to the regime of the film boiling collapse of the underheated liquid, which is still underexplored. The experiments on the liquid drops fragmentation are complemented by those with surface boiling at the solid metal samples of semi-spherical form. The connection between the vapor explosion of water and the increase of the surface wettability is confirmed. The video material, indicating the possibility of formation of liquid jets that strike the hot surface during the collapse of the vapor shell, is obtained. The time interval (duration of the contact) between the first contact of the coolant with the hot surface and the explosion boiling of the liquid is experimentally determined. The dependence of the contact duration on the temperature of the overheated wall is determined and its comparison with the theoretical estimations is provided.
The Development of a Mathematical Model of an Evaporative System with Film Flows
Authors: Minakov A V , Lobasov A S , Zaitsev D V , Kabov O A 
Published: December 2020

Abstract
A spatial mathematical model of the evaporation system using film flows has been developed. A numerical study of several modes of film flow in an evaporation cell at a heater temperature below the boiling point has been carried out. The characteristics of the film flow and the features of the coupled heat and mass transfer processes in the gas-film-metal substrate system have been studied. Good agreement between the calculation and the experiment on the main parameters of the wave motion of the film and the heat transfer characteristics has been obtained.
Study of heat exchange and hydrodynamics on the model of fuel assembly with microfuels
Authors: Tupotilov I A , Varava A N , Dedov A V , Zaharenkov A V , Komov A T , Loktionov V D , Mirnov S V , Smorchkova Y V 
Published: December 2020

Abstract
The design of the working section was developed and the hydraulic circuit of the TVS-MPEI experimental bench was modernized to study hydrodynamics and heat transfer in a fuel assembly with microfuel. Experimental studies were carried out to determine the pressure loss and hydraulic resistance coefficient of a cylindrical ball filling with the following operating parameters of the coolant: p = (2 ÷ 7) MPa, G = (0.05 ÷ 0.5) kg/s. The technology of installation, output and sealing of thermocouples at the work site has been developed. The first experimental data on the temperature distribution inside the ball filling were obtained.
Heat transfer under powerful heat release in supercritical-pressure liquids
Authors: Rutin S B , Skripov P V 
Published: December 2020

Abstract
The aim of the present article is to summarize the results of pulse experiments performed under conditions of powerful heat release in supercritical-pressure liquids. The parameters of the discussion are the values of the speed of crossing the vicinity of the critical temperature and pressure reduced to the critical one. These results obtained for “heater-probe / supercritical fluid” system and based solely on comparison of the primary data indicate a threshold decrease in the intensity of heat transfer near the critical temperature. The purpose of this summary is to suggest a relatively simple approach to reconciling the pulse heating results with the peaks of thermophysical properties derived from experiments in stationary conditions. It is assumed that the action of gradient in temperature and the presence of heat-transfer surface can serve as factors that suppress large-scale fluctuations in pulse heated system, leading to a “smoothing” the critical enhancement of the properties.
Thermal analysis and ignition of HEM containing aluminum and titanium borides
Authors: Korotkikh A G , Sorokin I V , Selikhova E A , Arkhipov V A 
Published: December 2020

Abstract
This paper describes the data of oxidation kinetics for metal fuels and ignition characteristics for the high-energy material (HEM) samples based on ammonium perchlorate, ammonium nitrate and an energetic binder, containing the powders of Al, B, AlB2, AlB12 and TiB2. The thermal oxidation of metal fuels and the thermal decomposition of the HEM samples were determined using a combined Netzsch STA 449 F3 Jupiter analyzer. The ignition of the HEM samples was studied using the radiant heating setup based on continuous CO2 laser in the heat flux density range of 90–200 W/cm2. Experimentally it was found that the complete replacement of aluminum powder by amorphous boron in the HEM sample significantly reduces the ignition delay time (by 2.2–2.8 times) in the same heat flux density. The ignition delay time of the HEM sample containing titanium diboride powder decreases slightly (by 10–25%) relative to the ignition delay time of the Al-based HEM.
Decrease in carbon monoxide release and incomplete burning of fuel during activated combustion of coal
Authors: Larionov K B , Zenkov A V , Mishakov I V , Gromov A A 
Published: December 2020

Abstract
Combustion products and ash residue of bituminous coal modified with copper salts (Cu(NO3)2, Cu (CH3COO)2andCuSO4) in amount of 5 wt.% are studied. Application of additives to the coal samples is carried out by the method of incipient wetness impregnation with preliminary dissolution of the additive in aqueous-alcohol solution with a volume ratio of C2H5OH/H2O = 50/50. Combustion of coal samples is conducted in combustion chamber at temperatures of the heating medium of 500–700°C. Gas-phase combustion products are analyzed using a flow-through gas analyzer. Application of additives contributes to the reduction of incomplete fuel burning. The maximum change (7.1 times) has been recorded for the sample modified with Cu(NO3)2 at a heating medium temperature of 600°C. Analysis of gas-phase products has shown that activation of the combustion process with copper salts allows significantly reducing the volume of formed CO, providing more complete oxidation of combustible products to CO2.
Development of a simplified mathematical model for a foil gas bearing operation
Authors: Volkov-Muzylev V V , Borisov Yu A , Beschastnykh V N 
Published: December 2020

Abstract
A theoretical study of a gas flow process in a clearance, changing during operation between a compliant foil of a foil gas bearing and a rotor of a high-speed turbomachine, is presented. The approaches to mathematic simulation of the position of the compliant foil of the gas bearing, deforming under the influence of gas pressure on the outer surface and a system of distributed springs on the inner surface, are developed. An example of numerical simulation of the foil gas bearing in order to obtain an elastic line of the compliant foil under the influence of gas forces, acting in a wedge-shaped clearance, is considered.
Features of water circulation on the Black Sea northwestern shelf based on physical reanalysis results
Authors: Dorofeyev V L , Sukhikh L I 
Published: December 2020

Abstract
The paper studies the main features of water circulation on the northwestern shelf (NWS) of the Black Sea. The study is based on a physical reanalysis performed previously. The result of reanalysis is a set of hydrodynamic fields for a period of twenty years on a regular grid with a discreteness of one day. To analyze the general properties of the currents on the NWS, the fields were averaged over a monthly period, and further analysis used the monthly average values of them. Spreading of the rivers outflow and wind stress are basic mechanisms, which controls the flow structure in the upper layer of the NWS. Surface currents are directed mainly to the southwest. Along the western coast, a compensatory current is formed, directed to the south, with the exception of the summer months, when the effects of wind are significantly weakened. A characteristic feature of the waters near the western shore is the strong horizontal stratification caused by fresh water with rivers outflow, mainly the Danube. An interesting feature of the circulation on the NWS is presence of a subsurface coastal jet counter-flow directed to the north. The center of this counter-flow is located approximately on the horizon of 20 meters. Its depth may vary, but the counter-flow itself is observed throughout the year.
Dynamics of laser plasma convective plume in high pressure xenon
Authors: Kotov M A , Lavrentyev S Yu , Solovyov N G , Shemyakin A N , Yakimov M Yu 
Published: December 2020

Abstract
This paper presents the results of numerical simulation of convective plume pulsations from a concentrated heat source equivalent to a continuous optical discharge (COD) in high pressure xenon compared to originally obtained experimental results. Simulated dynamic distributions of temperature, density and velocity of the gas around small spheroidal heat release zone are obtained, showing the process of formation of toroidal vortices in the convection zone, leading to the appearance of pulsations. The simulation results are qualitatively and quantitatively consistent with previously obtained experimental data.
Viscous fluid flow in a microchannel with hydrodynamic traps
Authors: Solnyshkina O A , Fatkullina N B 
Published: December 2020

Abstract
Simulation of creeping flows in complex three-dimensional domains is crucial for microfluidics applications, creating multipurpose microfluidic devices, which are used, for example, to study multistage chemical reactions and as analytical devices in medicine.In this work we study the features of the incompressible viscous fluid flow in a flat microchannel with a nontrivial internal structure (the hydrodynamic traps of various configurations) under the constant pressure drop.The three-dimensional boundary element method, improved by utilization high-efficient fast multipole method and heterogeneous computational workstation, was used in numerical simulation.We studied the flow pattern around C-shaped hydrodynamic traps distributed in a flat microchannel and consisting of five cylindrical elements of the same size. Such geometry is widely used in microfluidic devices for fixing particles in the flow, for example, biological objects during tests in medicine. The influence of the distance between the rows of traps on the flow pattern and distribution of the longitudinal and transverse components of the flow velocity was considered.
Software and hardware system for diagnostics of deposits inside the vortex chamber
Authors: Semenov D O , Dvoynishnikov S V , Rakhmanov V V , Meledin V G 
Published: December 2020

Abstract
This paper is devoted to the development of software for the system of visualization of deposits inside vortex chambers and the creation of algorithms for improving the quality of visualization. As part of the work, software for the microcontroller, which manages the entire hardware part, was created. An application for PC for visualizing images from the camera to the experimenter has been developed. Algorithms for correcting the distortion and subtracting the background are implemented for better analysis of the geometry of deposits.
Thermodynamic modeling of carbon nanoparticle C32 heating in the nitrogen environment
Authors: Barbin N M , Yakupova L V , Terent’ev D I , Kuanyshev V T 
Published: December 2020

Abstract
Using computer thermodynamic modeling, the behavior of carbon nanoparticles was studied C32when heated in nitrogen atmosphere at pressure 105 Pa. Modeling was carried out using a software package TERRA. Experiment temperature range – from 273 to 3373 κ. A graph of the carbon balance in the system is constructed C32-N2, physical and chemical processes are described. The equilibrium constants of reactions with the allocation of temperature ranges are calculated and graphs of the dependence of the equilibrium constants of reactions on temperature are given.
Thermal analysis of mechanochemically activated humic acids of brown coal
Authors: Mamylov S G , Skripkina T S , Tikhova V D , Bychkov A L , Lomovsky O I 
Published: December 2020

Abstract
Humic acids of brown coal before and after mechanochemical treatment under various conditions were studied by TG and DSC (carried out both in air and in an inert atmosphere, with the temperature range of 300–800 K), and gel permeation chromatography. The obtained data were used to calculate the values of the energy of activation and the thermal effects for each stage of thermal decomposition. Influence of mechanochemical treatment upon humic acids thermolysis stages was shown. Hypothesis of thermal stages chemical interpretation was proposed. The staged decomposition of humic acids includes the stages of decarboxylation of acid groups of various types. A change in the staging of decomposition is observed upon mechanochemical introduction of alkali into humic acids, associated with the conversion of acid groups to the salt form.
Data sources on the thermophysical properties of metals and alloys, a sketchy overview
Authors: Savchenko I V 
Published: December 2020

Abstract
A brief review about data sources on the thermophysical properties of metals and alloys is presented. The basic advantages and disadvantages of popular information sources are shown. Approaches to the choice of the most reliable data are discussed in general. A simple algorithm for searching the most appropriate property information for specific cases is recommended.
Development and experimental researches of refrigerating unit with a radar station
Authors: Beschastnyh V N , Borisov Yu A , Kosoi A S , Nizovskiy L V 
Published: December 2020

Abstract
The antennas of modern radar devices need effective cooling, which is carried out by forced circulation of the coolant. A new pneumohydraulic diagram of a refrigerating unit, which allows achieving effective heat removal from an antenna of a radar station with minimal overall dimensions and weight, is considered in this paper. The paper presents the results of experimental research related to an operation of the refrigerating unit at ambient temperatures equal to +50 °C and -50 °C within the temperature range from −50 °C to 10 °C.