bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental progress of hybrid operational scenario on EAST tokamak
Authors: Gao X. , Zeng L. , Wu M.Q. , Zhang T. , Yang Y. , Ming T.F. , Zhu X. , Wang Y.M. , Liu H.Q. , Zang Q. , Li G.Q. , Huang J. , Gong X.Z. , Li Y.Y. , Li J.G. , Wan Y.X. 
Published: July 2020

Abstract
Extensive experiments of advanced scenario development, which contribute to the ITER hybrid operational scenario have been carried out on experimental advanced superconducting tokamak (EAST) tokamak recently with the ITER-like tungsten divertor. The

β
N

in this operational scenario is intermediate up to 2.1 (EAST#78987,

β
N

∼ 2.1, I
p ∼ 0.45 MA, q
95 = 3.7,

B
T

∼ 1.5 T, 3 MW neutron beam injection and 1 MW 4.6 GHz lower hybrid wave). In these hybrid H-mode plasmas, the internal transport barrier (ITB) has been frequently observed with central flat q profile and it is found that the fishbone mode (m/n = 1/1) can be beneficial to sustain the central flat (q(0) ∼ 1) q profile, thus a stable ITB can be obtained. In this case, better plasma performance is achieved. The formation of the ITB of the electron density is related to the fishbone activities. Energy transport analysis shows that the fishbone instabilities have a suppression on electron turbulent energy transport, while the ITB of ion temperature is due to the suppression of high-k modes (electron temperature gradient). The mechanism of turbulence suppression from fishbone instabilities in the EAST tokamak is not clear and needs more investigation. It is also observed that the power threshold for ITB formation is

≥

3.5 MW, which is consistent with the scaling law for other tokamaks. The dimensionless parameter

G

(

=

H

89

β
N

/

q

95

2

) obtained in the EAST reaches 0.3, but is still lower than the ITER hybrid scenario design (G ≥ 0.4) and needs more extension. Further investigation of extending the operational regimes, such as expanding the ITB foot outwards, would be important for the development of the hybrid and steady-state scenarios for next-step fusion devices like ITER and CFETR.
Mini-EUSO onboard of the ISS for UV terrestrial and cosmic emission detection: space qualification and calibration
Authors: Cambiè G 
Published: July 2020

Abstract
The Mini-EUSO (Multi-wavelenght Imaging New Instrument - Extreme Universe Space Observatory) telescope is designed to observe the UV emission of the Earth from the vantage point of the International Space Station (ISS) in low Earth orbit. Mini-EUSO will map the Earth in the UV range (300 - 400 nm) offering the opportunity to study a variety of atmospheric events such as Transient Luminous Events (TLEs) and meteors, as well as searching for Strange Quark Matter (SQM) and bioluminescence. The instrument comprises a compact telescope with a large field of view (44°), based on an optical system employing two Fresnel lenses for light collection, focused onto an array of 36 multi-anode photomultiplier tubes. The resulting signal is converted into digital, processed and stored via the electronics subsystems onboard. In addition to the main UV detector, Mini-EUSO contains two ancillary cameras for complementary measurements in the near infrared (1500 - 1600 nm) and visible (400 - 780 nm) range and also a SiPM (Silicon PhotoMultiplier) array which will increase the Technology Readiness Level (TRL) of this ultrafast imaging sensor.
Fragmentation and agglomeration of biomass in fluidised bed pyrolysis and combustion
Authors: Litun D S , Ryabov G A , Folomeev O M , Shorina E A , Smirnova O A 
Published: July 2020

Abstract
The results of experiments on primary fragmentation of wood biomass particles during fast pyrolysis in an inert medium at different temperatures are presented. Growth of temperature and initial size in the range t = 800 – 950°C increases the probability and intensity of fragmentation in the process of rapid pyrolysis of wood particles. Oblong particles are more prone to fragmentation than quasi-circular (cubic) particles with the same equivalent diameter. The critical diameter of fragmentation for spruce wood particles at a process temperature of 950 °C is dv0 =18-19 mm at the ratio of longitudinal and transverse size h/a =1 and is in the range of 7-9 mm at h/a =8. Study of microstructure and chemical composition of coke particles (fragmentes) by microscope with SEM analysis showed existence of thin outer layer (0-15 μm) on the particle faces, containing increased quantity of mineral components. Microspheres with a size of 13-23 μm and increased content of sulfur were detected on the particle faces, resulting at 950°C. Coinciding of maximum and minimum of chlorine, sodium and potassium content in the outer layer denotes on existence of sodium and potassium chlorides on the surface of coke particles. Results of experimental studies of physical and chemical processes occurring between the fuel ash and the bed materials under prolonged temperature exposure were obtained. The aim of these studies was to determine the time and proportion of agglomerated (sintered) particles of several types of biomass depending on the bed temperature. The experiments were carried out in a furnace on biomass ash, sand and mixture of sand and ash. First experiments showed a clear dependence of the temperature of agglomeration beginning on the potassium concentration in the bed and gave the boundary values of the concentrations and temperatures in the bed.
Physical and chemical processes simulation of organic wastes processing by the method of high-temperature oxidation in the melted slag
Authors: Markelov A Yu , Kudrinskiy A A , Anpilov S V , Shiryaevsky V L 
Published: July 2020

Abstract
Recycling of municipal waste is associated with accumulation of significant amounts of sewage sludge. The paper proposes a technology for the thermal utilization of sewage sludge with vitrification of a non-combustible residue. The paper presents the results of numerical simulation of the physical and chemical processes that accompany the high-temperature oxidation of pre-dried and pre-pelleted sewage sludge on the surface of the slag melt in a pilot plant with the melter capacity of up to 100 kg/h pellet. The mathematical model of the melter has been created and numerical calculations of the flow of high-temperature gaseous medium supplied by burner devices in the working volume of the furnace have been made in a stationary approximation taking into account the thermophysical and chemical processes occurring in the raw material, fed in the form of dry pellets (sediment).
Simulation of thermal explosion on the base of solution of the equation for the probability density function of particle temperature fluctuations
Authors: Derevich I V , Klochkov A K 
Published: July 2020

Abstract
The influence of temperature fluctuations of gas on the thermal explosion of particles with internal exothermic reactions is considered. The dependence of the rate of a chemical reaction on the concentration of a gas reagent is taken into account. Based on a rigorous system of heat and mass transfer equations, equations for the average temperature and concentration of the reagent inside the particle are obtained. A study of the dynamics of changes in the concentration of reagents and temperature inside the particle in a random field of temperature is carried out on the basis of the probability density function. Based on the solution of the systems of stochastic ordinary differential equations, a method of direct numerical simulation of random temperatures and reagent concentration in a particle is developed. A method for solving the equation for the probability density function is created. The results of comparing the empirical probability density function obtained by direct numerical simulation and the results of solving the equation for the probability density function are presented.
Gradient heat flux measurement in study of heat transfer during steam condensation inside pipes
Authors: Babich A Y , Zainullina E R , Sapozhnikov S Z 
Published: July 2020

Abstract
The article is about the application of the gradient heat flux measurement in the study of heat transfer during steam condensation at the inner surface of the pipe during different directions of water and steam supply. The installed gradient heat flux sensors (GHFS) and thermocouples did not disturb the condensate film flow on the pipe surface. Heat flux per unit areas and temperatures were measured along the length of the pipe. The obtained results confirmed the high informative of gradient heat flux measurement, as well as the capability of GHFS operating under experimental conditions.
Combustion-driven gas-dynamic CO2-laser on the basis of modern aviation engines
Authors: Boreisho A S , Vovk M Yu , Edigarev A D , Kiselev I A , Kulalaev V V , Morozov A V , Orlov A E , Smirnov P G 
Published: July 2020

Abstract
Combination of combustion-driven gas-dynamic lasers with gas-turbine turbojet and turbo-shaft engines has been considered. Development of aviation technologies has been analyzed. Output performance of a laser taking air from modern helicopter and airplane engines taking into account ensuring exhaust of spent active medium into the ambient atmosphere has been determined. The application of penetration cooling of the laser nozzle bank blades has been evaluated.
Modeling the influence of the river on the wind pattern of Krasnoyarsk
Authors: Meshkova V D , Dekterev A A , Gavrilov A A , Filimonov S A , Litvintsev K Yu 
Published: July 2020

Abstract
The article analyzes the environmental situation in the city of Krasnoyarsk based on data of the Ministry of Natural Resources and the Ministry of Ecology and Environmental Management of the Krasnoyarsk Territory. The influence of the non-freezing Yenisei River on the movement of air masses over the city is considered based on numerical simulation. The obtained results demonstrate the ability to quickly simulate the wind pattern of the city, taking into account the heterogeneous nature of the terrain, heat transfer, wind load, and the influence of the river.
Improving the energy efficiency of ship tank heating systems
Authors: Bagaev D V , Syraleva M N , Kudinovich I V 
Published: July 2020

Abstract
One of the challenges for creating objects of marine equipment operating in arctic conditions is to prevent freezing of fluids in tanks at extremely low temperatures as it may cause damage to the ship and its systems. This problem can be solved with efficient heating systems for ship tanks. In the paper the ballast tank heating simulation and optimization of heating coil position is discussed. The considered heating coil is typical for icebreakers and ice-class vessels (Arc 5 and above). On the basis of the performed computations the recommendations for improving the energy efficiency of ship heating systems are formulated.
The unified approach to a definition of effective conductivity index of percolating cluster in macroscopically disordered environments
Authors: Kolesnikov B P 
Published: July 2020

Abstract
The paper proposes the unified approach to a definition of effective conductivity index of percolating cluster’s t fractal, quasi-fractal and n homogeneous parts. The approach is based on probabilistic-statistical nature of percolation cluster’s formation. Two functions t (ϑ) and n(ϑ) are presented. By the use of simple exponentiations they allow describing the behavior of maximum of critical macroscopically disordered environments’ effective conductivity in case of the given values of concentration ϑ elements of conductive component from percolation threshold ϑ = ϑc to their entire consolidation ϑ = 1.
Hydrodynamics of the developed pulsating laminar flow in a flat channel in the quasi-stationary region
Authors: Valueva E P , Zyukin V S 
Published: July 2020

Abstract
The hydrodynamic characteristics of the developed pulsating laminar flow in a flat channel – the longitudinal component of the velocity vector, the dimensionless pressure gradient, and the shear stress on the wall — were investigated. The calculations were carried out in a quasistationary region, i.e, under relatively low frequencies of oscillations of the cross-section averaged velocity. To obtain data in a quasistationary region, we analysed and used the results of the calculations of a stationary developed flow. The calculations of the system of the stationary motion equations and continuity equations were carried out by the finite difference method. The calculation results turned out to be consistent with the data obtained earlier by other authors. It has been found that at high amplitude of oscillations of velocity averaged over the cross section and exceeding one, coefficients of hydraulic resistance and friction resistance near the channel entrance averaged over the period are higher than these values for a steady flow.
The experimental investigation of the effect of nanoparticle material on the evaporation rate of nanofluids
Authors: Lobasov A S , Minakov A V , Pryazhnikov M I 
Published: July 2020

Abstract
It was experimentally investigated the nanofluids evaporation rate in this study. The nanofluids were prepared using the distilled water and different nanoparticles. The nanoparticles of aluminium oxide, silicium and zirconium dioxides, as well as the nanodiamonds were used. The average diameters of the particles were as follows: SiO2 – 25 nm, ZrO2 – 105 nm, Al2O3 particles – 43 nm and nanodiamonds – 5 nm. The Simultaneous Thermal Analyzer STA 449 C Jupiter (NETZSCH) was used to carried out the study of the evaporation rates of fluids. The dependence of the evaporation rate on the material of the nanoparticles was investigated. It was found in that study that the evaporation rate significantly depends on the nanoparticles material. Moreover, based on the obtained results it was shown, that the evaporation rate of nanofluids monotonically increases with an increase of nanoparticles volume concentration.
Eddy-resolving numerical simulation of silicon melt convection in a Czochralski crucible: effects of radiation from the free surface at various crucible rotation rates
Authors: Abramov A G , Smirnov E M , Smirnov S I 
Published: July 2020

Abstract
The contribution covers results of numerical study based on conjugate heat transfer formulation of turbulent silicon melt convection in an industrial system for CZ Si-crystal growth of 100 mm diameter crystals. The computations have been performed using an eddy-resolving method treated as Implicit LES for two values of the emissivity from the melt free surface (0.25 and 0.3) and the crucible rotation rate of 2 and 5 rpm. The effects of these parameters on melt convection and characteristics of heat transfer are analyzed.
Experimental studies of the influence of hydrodynamics on heat transfer at evaporation and boiling of a film irrigating a bundle of horizontal finned tubes
Authors: Gogonin I I 
Published: July 2020

Abstract
A feature of operation of some devices, such as heat pump steam generators, evaporators of refrigerating machine, steam generators of binary freon station, etc., is a low value of specific heat fluxes. Heat transfer regimes occur, when boiling in the film is just beginning and the heat transfer rate during evaporation is comparable to that during boiling. Tube finning is a well-proven way to intensify heat transfer, both during evaporation and boiling. However, there are insufficient data on the choice of finning parameters and methods for evaluating heat transfer during boiling of a film that irrigates a bundle of finned tubes. This paper presents an algorithm for calculating heat transfer during evaporation and boiling of a film that irrigates a bundle of finned tubes, and compares the calculated and experimental data. The calculated parameters turn out to coincide satisfactorily with the experimental data.
Improving the schemes for ash removal from hopper ash collectors based on modeling
Authors: Elsukov V K , Ogar P M 
Published: July 2020

Abstract
Various ash removal schemes from the hopper ash collector to such transportation devices as hydraulic ash disposal channels, are analyzed. The drawbacks of these schemes are: high flow rates of flush water, gas flows through common ash gutters between bunkers of different pressure, and clogging of ash flows. The paper considers the invention and its introduction, which will eliminate or reduce these drawbacks by increasing the reliability of the circuits and centralizing the discharge of ash. The high efficiency of the invention under consideration is illustrated by the example of its practical use in the Galachinsk boiler house situated in the territory of Bratsk. To determine the design and operational parameters of the above mentioned invention its mathematical model has been developed based on the balance of forces acting in it (on the continuous gate). With the help of the obtained model, the structural and operational parameters of the device are calculated in three possible variants of its implementation. In these cases, the number of sections of different pressure changes and the presence of a periodic action shutter is taken into account. The determined parameters are the maximum and minimum heights of the ash column, the mass and the position of the load of the continuous gate. Ash collector performance indicators affecting these parameters have been identified. An ash collector of the TsBR-150U-1280 type, which has ash bunkers with three different values of vacuum, is accepted as an example. On the basis of the developed model, an algorithm has been compiled for calculating the design and operational parameters of the device under consideration during its design.
Thermal ablation of biological tissue by high intensity ultrasound
Authors: Andreeva T A , Belyankin A B , Berkovich A E , Bykov N Y , Kozyrev S V , Ya Lukin A 
Published: July 2020

Abstract
The paper discusses the effect of a series of focused high-intensity ultrasound pulses from a multi-element transducer on the biological tissue. The simulation of the ultrasound intensity field in a homogeneous medium uses the Rayleigh integral. The thermal problem modelling is based on the numerical solution of the heat equation. The advantages of processing a given volume of tissue with pulses, whose focal points over time consistently diverge from the geometric focus of the transducer, have been demonstrated. The effect of the time delay between pulses on the nature of tissue heating and the size of the thermal ablation region is analyzed. The issues of scaling for the problem of heat distribution are discussed.
Diffusion and convective mixing modes of binary gas mixtures dissolved in the third component
Authors: Kossov V N , Fedorenko O V , Mukamedenkyzy V , Tuken M 
Published: July 2020

Abstract
The numerical investigation of the mixing of an isothermal binary gas mixture dissolved in the third component has been carried out. The boundary relation that determines the change of “diffusion – concentration convection” modes is obtained in the framework of a linear stability analysis for a flat vertical channel with mass-impermeable walls. Diffusion and convection regimes were studied for a mixture of a pair of gases H2 and Ar, which was diluted first with a light and then with a heavier component. It is shown that the nature of the ballast gas has a significant effect on the diffusion and convective mixing regimes of the main diffusing components.
Thermal characteristics of the radioactive graphite -CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere
Authors: Barbin N , Kobelev A , Terent’ev D , Alekseev S 
Published: July 2020

Abstract
The article considers thermal characteristics of the radioactive graphite–CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere. Thermodynamic calculations were carried out in the Terra program. Four temperature ranges with changes of thermal characteristics of the radioactive graphite–CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere have been determined.
Parametric identification of differential-difference models of heat transfers in the systems of bodies
Authors: Pilipenko N V , Zarichnyak Y P 
Published: July 2020

Abstract
The combined inverse heat conduction problem (IHCP) was solved to restore the boundary conditions of heat exchange, in particular, unsteady heat flux, while simultaneously refining the thermophysical properties of the object material by parametric identification of the differential - difference models (DDM) of heat transfer in the object of study. The differential-difference model is a system of first order ordinary differential equations with respect to the state vector. The type of feedback, control, and measurement matrices included in the DDM is established. A priori parametrization and parametric identification of the heat transfer model was performed. The parametrization involves approximation of the desired heat flux by B-splines of the first order for each piecewise-linear segment. With parametric identification, the discrepancy between the model and experimental values of the parameters is minimized using a recurrent linear Kalman filter. Taking into account the parametrization and parametric identification, the time-varying heat flux at the body boundary was restored and its thermal and physical properties, in particular, thermal conductivity, were simultaneously refined. The uncertainty of restoration of parameters based on the Gram matrix is estimated. The boundaries of confidence areas for determining the desired parameters based on the sensitivity functions, which are obtained by solving the heat transfer equations, are established. The results of model experiments, in which initial estimates of the desired parameters were set twice less than the true ones, are given.
Renewable energy in the Russian Arctic: Environmental challenges, opportunities and risks
Authors: Morgunova M O , Solovyev D A , Nefedova L V , Gabderakhmanova T S 
Published: July 2020

Abstract
The Arctic is a specific geographical region with extreme climate conditions, vulnerable environment, but rather intensive ongoing industrialization. The Arctic requires alternative solutions to provide energy supply to the energy consumers due to the growing energy demand and small-scale decentralized character of energy supply. At the moment, the largest part of energy consumption in the region is covered by hydrocarbon energy resources delivered from the mainland. Renewable energy technologies may be efficiently implemented to cover the needs of small scale decentralized energy consumers in the Russian Arctic, but at the moment they are applied on a very modest scale. The current study analyses and discusses the main challenges and risks related to renewable energy resources use in the Russian Arctic. Further, the study elaborates on the issues related to the environmental challenges and climate change-related threats, their relationship and influence on the technological choices of the future energy supply in the region, addressing the perspectives of sustainable development of the Russian Arctic.