bluuebunny/crossref_metadata_2025_split huggingface dataset:
Universal statistics of Fisher information in deep neural networks: mean field approach*
Authors: Karakida Ryo , Akaho Shotaro , Amari Shun-ichi 
Published: December 2020

AbstractThe Fisher information matrix (FIM) is a fundamental quantity to represent the characteristics of a stochastic model, including deep neural networks (DNNs). The present study reveals novel statistics of FIM that are universal among a wide class of DNNs. To this end, we use random weights and large width limits, which enables us to utilize mean field theories. We investigate the asymptotic statistics of the FIM’s eigenvalues and reveal that most of them are close to zero while the maximum eigenvalue takes a huge value. Because the landscape of the parameter space is defined by the FIM, it is locally flat in most dimensions, but strongly distorted in others. Moreover, we demonstrate the potential usage of the derived statistics in learning strategies. First, small eigenvalues that induce flatness can be connected to a norm-based capacity measure of generalization ability. Second, the maximum eigenvalue that induces the distortion enables us to quantitatively estimate an appropriately sized learning rate for gradient methods to converge.
H2 controller design on engine rotor rotation
Authors: C A Ramírez V , Grisales-Noreña L F , Montoya O D 
Published: December 2020

Abstract
This article exposes the implementation of the H2 controller, which is rare in the literature because it is a more robust control and not only errors but also disturbances that can affect the dynamics of the control system are considered. The deduction of the equations for the continuous and discrete case is shown, which is little identified in this type of controllers and finally the implementation of said control over the rotation angle of the rotor of a motor is exposed, which is of great utility and importance. in electrical power systems for the generation and service of energy.
Problem of the P-Stockings applied to the location of facilities
Authors: Mesa F , Devia D , Ospina R 
Published: December 2020

Abstract
One of the problems derived from the overcrowding of cities and industry is the location of optimal facilities, these types of problems suffer from the problem of dimensionality themselves. In the following article, the problem is formulated in a mathematical way and it is approached from a metaheuristic epistemology which is the only methodology for now to find local optimum, since these optimization problems are still open in the scientific literature because they are considered problems of nondeterministic polynomial time. The explored technique is that of genetic algorithms which uses the classical theory of evolution to formulate and solve optimization problems.
Characterization of error sources in an inertial unit using Allan variance and nonlinear parameter adjustment
Authors: Hernandez W A , Castillo-Corredor J S , Ramos-Cifuentes J A , Fuentes F , Castañeda L F 
Published: December 2020

Abstract
Locating in space is essential for devices that perform navigation. currently inertial measurement units have been developed to allow navigation, however, this type of sensors present different errors in measurements. They have different errors that appear and accumulate when measurements advance. For this reason, the characterization of the error sources presented in sensor BNO055 is performed; data is acquired using a Raspberry Pi and Allan’s variance method was used for data analysis. A parameter fit is made in the error equation using the Levenberg-Marquardt numerical method a method commonly used in experimental physics.
Modeling of thermal and gas dynamic processes in additive shell and tube heat exchangers
Authors: Pugachuk A S , Fominyh N K , Gavrilova Yu A 
Published: December 2020

Abstract
As part of a gas microturbine engine development, a number of new heat exchanger flow channels, which are produced by using additive technologies, are considered. Geometric three-dimensional models of several heat exchanger elements (with internal, external and combined finning – 3 and 6 rows of ribs, spade spiral of three sizes) are created. Also a mathematical modeling of heat carriers in their flow channels is carried out, taking into account heat transfer through the walls. The analysis of calculated thermohydraulic parameters, namely the heat power and pressure losses, is realized. The spade shape of the heat exchanger element allows intensifying heat exchange (comparable to a 3-fin pipe). It has lower hydraulic resistance compared to 6-fin pipes. It has been found that the change in a standard size of spade spiral pipes does not affect their heat exchange characteristics. The disadvantage of pipes with internal fins is a rapid increase of hydraulic resistance during the operation due to a deposition of microturbine exhaust gases soot.
Tracer visualization of vortex breakdown patterns in confined and unconfined flows
Authors: Skripkin S G , Tsoy M A , Naumov I V 
Published: December 2020

Abstract
Current work deals with the study of swirling laminar flows in confined and unconfined flows in order to identify common patterns considering the phenomenon of vortex breakdown. Two types of vortex breakdown patterns are created: spiral and bubble. To catch the main flow features the modern tracer visualization technique adapted to experimental conditions is used. Measurements of velocity distributions are conducted via two-component LDA system. This work also confirms some ideas proposed by (Jones et al. 2015) about generalization of vortex breakdown conditions in different geometries.
Heat exchange in the back lip cavity of the large solid-propellant rocket motor
Authors: Benderskyi B Ya , Chernova A A 
Published: December 2020

Abstract
Issues of numerical modeling of spatial gas dynamics and heat exchange in the back lip cavity of the combustion chamber of a large solid-propellant rocket motor (SRM) are considered. Topological features of the flow structure and thermophysical parameters near the nozzle cap in the back lip cavity are analyzed. Distribution of the heat transfer coefficient over the nozzle bottom surface in the back lip cavity is obtained by the radial coordinate. The obtained dependences fairly correlate with the known experimental data.
Computational and experimental study of 3D flow near the cube immersed in the turbulent free convection boundary layer on a vertical heated plate
Authors: Chumakov Yu S , Levchenya A M , Smirnov E M 
Published: December 2020

Abstract
Results of a coordinated computational and experimental study of time-averaged velocity and temperature fields in the vicinity of an adiabatic cube that is inserted into the turbulent free convection vertical-plate boundary layer are presented. The numerical simulation was based on the steady-state RANS approach using the k-ω SST turbulence model and a version of the differential Reynolds stress model (DRSM). The hot-wire technique was used for velocity measurements, simultaneously with temperature measurements by an accompanied “cold” wire. Two turbulence models produced similar vortex flow structures near the obstacle; however some important quantitative distinctions were observed. The velocity value profiles predicted for the middle vertical plane showed generally a good accordance with the hot-wire measurements carried out in this plane, especially in the DRSM case.
Experimental and numerical study of gravitational sedimentation of the polydisperse water-in-oil emulsion
Authors: Valliullina V I , Mullayanov A I , Musin A A , Kireev V N , Kovaleva L A 
Published: December 2020

Abstract
Experimental and numerical studies of the process of gravitational deposition of a polydisperse water-in-oil emulsion are carried out. The dynamics of emulsion deposition is determined based on the results of digital image processing. Histograms of the size distribution of emulsion droplets at different sampling depths during deposition are obtained. A comparative analysis of numerical and experimental data is performed.
An experimental study of the integral characteristics of the intrachannel liquid film suction in a turbine stator blades cascade
Authors: Gribin V G , Tishchenko V A , Popov V V , Tishchenko A A , Gavrilov I Yu , Alekseev R A 
Published: December 2020

Abstract
This paper presents the results of an experimental study of the integral characteristics of the intrachannel liquid film suction in a flat cascade of turbine stator blades. Two slots for removing the liquid film from the interblade channel were arranged on the pressure surface of the stator blade. The experiments were carried out with initial steam wetness y
0 = 3 ÷ 9.5 % and theoretical Mach number downstream the cascade M
lt = 0.6 ÷ 0.78. The operation mode of the moisture removal system was determined by the relative pressure drop on the moisture-removing slots and varied over a wide range. The investigations were carried out for both the operation of the moisture-removing slots one at a time and the combined suction of the liquid film simultaneously through both slots. The measurement system used in the experiments allowed separately determining the mass flow rates of steam and liquid removed from the interblade channel. The obtained integral characteristics served to evaluate the influence of various factors on the efficiency of the intrachannel moisture removal system. Based on the analysis of the research results, recommendations on the design and operation of intrachannel moisture removal systems have been formulated.
Increasing the heat dissipation of an evaporator in the refrigeration system
Authors: Sazhin I A 
Published: December 2020

Abstract
The article considers the possibility of increasing the heat transfer of the evaporator of the refrigeration unit. The methods of Kutateladze-Sorokin, Baker, Baggs and Brill are used to diagnose the flow regimes of R-22, R-134a, R-600a refrigerants at gas contents from 0.7 to 0.95. The values of the Nusselt criterion, the heat transfer coefficient in the selected sections of the evaporator pipe are calculated. The results are consistent with known data. An example of changing the thickness of a liquid film of a refrigerant is considered to increase the heat transfer of the evaporator of a refrigeration unit.
Influence of the gravitational field variability on convective heat and mass transfer and on the free surface
Authors: Fedyushkin A I 
Published: December 2020

Abstract
The article is devoted to the influence of non-constancy of the earth’s gravitational field on fluid hydrodynamics and heat-mass transfer. The structure of convective fluid flow in a square cavity with lateral heated under constant and a variable on space gravity field. The changing diagonal symmetry of structure of convective flow and its effect on the distributions of temperature and concentration are considered. The results of modeling a problem of non-stationary flow of water with a free surface in a horizontal two-phase layer with an instantaneous change the acceleration of gravity from a constant g
0 to variable g(x) = g
0
x are presented. The nature of the wave change of the free surface of water with overturning, bursts of waves during intensive non-stationary flow in the horizontal layer caused by the changing of gravity from constant to variable is shown.
Thermal expansion of ice based gas hydrates
Authors: Belosludov V R , Zhdanov R K , Gets K V , Bozhko Y Y , Subbotin O S 
Published: December 2020

Abstract
This work aims at studying thermal expansion of ice Ih based gas hydrates that play important role in self-preservation effect of classical gas hydrates. Linear thermal expansion of ice Ih based hydrogen hydrates are calculated using a very effective statistical thermodynamic model of gas hydrates developed by the authors of this work. Molecular structures of all studied systems are obtained by MD simulations, and all parameters required by the model are obtained by using Quasiharmonic Lattice Dynamic approach. In accordance with our calculations, introduction of hydrogen into the system not only significantly affects the unit cell parameter of ice, but also increases linear thermal expansion and makes it comparable to the classical gas hydrates such as CH4, CO2, etc.
An experimental study of the evaporation rate of nanofluid droplets with SiO2 nanoparticles
Authors: Bochkareva E M , Miskiv N B , Nazarov A D , Terekhov V V , Terekhov V I 
Published: December 2020

Abstract
In this work, experimental data are presented on the evaporation rate of suspended droplets of distilled water and distilled water with the addition of nano particles of silicon dioxide during evaporation in an air stream with a low blowing rate. The measurements were carried out at Reynolds numbers calculated from the relative flow velocity Re <10. The evaporation rate of suspended droplets of distilled water and nanofluid was compared.
Experimental study of the motion and form of the vapor bubble floating in the annular channel at subatmospheric pressure
Authors: Dekhtyar R A , Ovchinnikov V V 
Published: December 2020

Abstract
An experimental study was made of the dynamics of a vapor bubble floating up in an annular channel at subatmospheric pressure. A vapor bubble was formed after boiling of an overheated degassed liquid in an annular channel formed by two tubes with diameter of 25 mm and 16 mm. The study shows that the dynamics of the vapor cavity during the ascent of vapor bubble in an annular channel has qualitative difference from the dynamics of gas bubble and has much in common with the dynamics of Taylor vapor bubble floating in a small round tube. One of the features of the behavior of the vapor cavity in the annular gap is that in the pulsation mode at the collapse stage, it can disintegrate into several parts.
Theoretical study of the self-preservation effect in CF4 gas hydrates
Authors: Zhdanov R K , Gets K V , Bozhko Y Y , Subbotin O S , Belosludov V R 
Published: December 2020

Abstract
This work studies thermodynamic properties of CF4 gas hydrates using the statistical thermodynamic model of inclusion compounds, developed in our laboratory and closely associated with Quasiharmonic Lattice Dynamic (QLD) and Molecular Dynamic Simulation (MD). Thermal expansion coefficient of CF4 gas hydrate is calculated at different hydrate composition. The thermal expansion coefficient is shown to be lesser than the thermal expansion coefficient of CH4 hydrates, but larger than ice Ih, that still indicates the presence of the self-preservation effect. The thermal expansion coefficient is very sensitive to the composition of the hydrate and can vary in a wide range. The same is true for the hydrate lattice parameter as well; it is shown that at certain conditions it may be even less than for hypothetical empty hydrate structure. The self-preservation effect may be applied for many aspects related to CF4 compound, especially for storage and transportation purposes in producing semiconductor electronics.
Influence of structural and phase composition on mechanical characteristics of laser welded joints of aluminium-lithium alloys
Authors: Malikov A G , Orishich A M 
Published: December 2020

Abstract
The paper presents the analysis of the structural and phase composition by the methods of electronic microscopy, X-ray diffraction analysis and synchrotronic radiation of the laser welded joints for the Al-Li alloys of the systems Al-Cu-Li and Al-Mg-Li without and after the post thermal treatment. It is shown that during the welding, strengthening phases dilute in the solid solution of the welded joint, and, in the case of Al-Cu-Li alloys, they concentrate over the dendrite boundary. The optimal post heat treatment restores the structural phase composition and mechanical properties of the weld.
The calculation of lean mixture burning in model combustors with flow swirling
Authors: Maiorova A I , Vasilyev A Yu , Sokolova E I 
Published: December 2020

Abstract
The testing of various turbulence models was conducted when calculating separated swirling flows. For burning simulation, a simple phenomenological model is presented. The model takes into account the gas swirling effect on the velocity of flame propagation. The developed technique is applied to the calculation of the burn-out of a lean mixture in model combustion chambers with three-tier swirlers. It is shown that the reversed organization of combustion with outside ignition is more efficient than the scheme with inside ignition. In the calculations, the mutual swirling of the flows behind the swirlers was varied and its effect on the burn-out rate of the mixture was considered.
Study on the pyrolysis of different coal in atmospheres of argon, carbon dioxide, and steam
Authors: Slyusarskiy K V , Kadchik D Yu , Asilbekov A K 
Published: December 2020

Abstract
The pyrolysis process is fundamental in many deep coal utilization technologies. The comparison of conversion of three different types of coal was carried out utilizing thermal analysis in the atmosphere of argon, carbon dioxide, and steam within the temperature range from ambient temperature to 1000°C. The anthracite, bituminous coal, and lignite of Siberian deposits were studied. It was found that within the temperature range of 20-700°C for bituminous coal and lignite, and within 20-800°C for anthracite, the differences between mass loss rate in inert medium and other studied samples were insignificant. While flue gases (from fossil fuels burnt with low excess air ratio) in general consist of carbon dioxide and steam. Thus, they could be used for the pyrolysis of studied fuels within the mentioned temperature ranges.
Numerical analysis of the bubble-particle interaction in an acoustic field
Authors: Pityuk Yu A , Burmistrov M E , Zarafutdinov I A 
Published: December 2020

Abstract
Features of the interaction of a bubble and a solid spherical particle in the presence of an acoustic field in the three-dimensional case are numerically studied using the boundary element method for potential flow. Multiparametric calculations are presented and dependences of the change in the volume of the bubble, dynamics of the mass center of the bubble and particle on the distance between the objects and their sizes are constructed. It is shown that during the bubble expansion, the particle repels from it, and during the bubble shrinkage it is attracted, the size of the particle determines its mobility. On average, over five periods of acoustic field oscillations, the distance between the objects decreases, which is due to the translational motion of the bubble in the compression phase. The features of the deformation of a bubble located near a solid spherical particle with small amplitudes of the acoustic field are studied.
Volumetric properties of iron in the solid and liquid states
Authors: Abdullaev R N , Khairulin R A , Stankus S V 
Published: December 2020

Abstract
Density and thermal expansion of pure iron are investigated using a gamma-ray at-tenuation technique in the temperature range of 1020–2090 K of solid and liquid states. The relative density changes of iron during allotropic trasformations and solid – melt phase transition are directly measured. The density of iron at room temperature is measured by the Archimedean method. The temperature dependence of the density of iron in the temperature range of 130–2090 K was constructed using the results of this work and a previous study of the thermal expansion of the a-phase. The data of this work are compared with the results of other authors.
Enhancing metal hydride thermal conductivity by forming compacts
Authors: Romanov I A , Borzenko V I , Kazakov A N 
Published: December 2020

Abstract
The development and implementation of metal hydride technologies face a number of challenges. One of the main problems is the low thermal conductivity of fine powders of hydride-forming materials. This feature, giving the relatively high values of the reaction heat of intermetallic compounds with hydrogen, leads to an increase in the cost of construction of vessels with metal hydrides and heat exchangers, which reduces the competitiveness of hydrogen-based technologies. One of the most promising ways to solve this problem today is the formation of compacts from metal hydride powders by pressing with additives that increase thermal conductivity. In this work, compacts based on AB5-type alloy with composition LaNi4.4Al0.3Fe0.3 prepared using various methods were studied and their properties were compared with the free bed of this alloy. Carbon nanofibers and nickel-foam were used as additives that improve the thermal conductivity of the compacts. The main methods of studying the properties of samples were measuring of hydrogen absorption and desorption PCT-isotherms and investigation of the temperature inside the samples during their heating and interaction with hydrogen. The compacts showed a noticeable improvement in thermal conductivity with a slight deterioration in hydrogen-adsorption properties, which is a promising result.
Graphene transfer from a copper surface to a silicon substrate
Authors: Smovzh D V , Kostogrud I A , Boyko E V , Morozova M A 
Published: December 2020

Abstract
The article presents a comparison of two methods of transferring single-layer graphene onto silicon substrates using poly (methyl methacrylate) (PMMA) and thermo-adhesive tape. The continuity of the transferred coating and the quality of the graphene film after the transfer stage were investigated. An analysis of the contaminants formed during the transfer of the graphene surface is carried out. It is shown that when using PMMA for transfer, heating of the samples leads to their damage due to thermal expansion and the formation of indelible impurities on the surface.
Investigation of the influence of low frequency electric fields on model water-in-oil emulsions
Authors: Kovaleva L A , Zinnatullin R R , Sultanguzhin R F 
Published: December 2020

Abstract
The article describes the mechanisms of coagulation and coalescence of emulsion droplets in electric fields, and also defines the frequency ranges at which coagulation and coalescence of emulsion droplets occurs, and the establishment times of these processes. The experiments revealed the tendency to increase the intensity of the studied processes with increasing field strength and salinity of the aqueous phase.
Contact angles in the presence of an electrical field
Authors: Kupershtokh A L 
Published: December 2020

Abstract
Three-dimensional computer simulations of the dynamics of sessile droplets in an electric field and without it are carried out on the basis of the lattice Boltzmann method (LBM). The dielectric droplets are placed on the surface of the lower electrode. The electrical and hydrodynamic parts of the problem are solved simultaneously. After application of an electric field, the droplets begin to lengthen in the field direction. The contact angle is measured after the droplet acquires its equilibrium shape. It is shown that the contact angle slightly increases with increasing the electric field due to electrostatic forces. Above a certain critical value of the electrical Bond number, the droplets cannot acquire a stable form, the elongation becomes unlimited, and the droplets are destroyed.
Experimental study of the temperature distribution over the surface of a heat supply object under heating conditions with a gas infrared emitter
Authors: Kuznetsov G V , Maksimov V I , Nagornova T A , Voloshko I V , Gutareva N Y 
Published: December 2020

Abstract
The experimental studies of the heat transfer processes in the system of radiator – air – heat supply object have been carried out to measure the surface temperatures of the fabric covering the model of the worker. The results obtained give grounds to conclude that when developing systems for ensuring the scheduled thermal regime of the local working zones of the large industrial premises under the conditions of radiant heating, it is necessary to take into account the spatial orientation of the surface areas of the clothing of the worker relative to the vector of the radiant energy flux.