bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of two numerical approaches for natural convection in cavities with energy sources
Authors: Gibanov N S , Miroshnichenko I V , Sheremet M A 
Published: December 2019

Abstract
A numerical investigation of two-dimensional natural convection in an enclosure with a local square energy source has been carried out. The presented problem has been solved by two numerical methods – first of all by the finite difference method using the non-primitive variables “stream function – vorticity” and by the lattice Boltzmann method. As a result the distributions of temperature fields and stream functions and also velocity fields have been obtained. A comparison of the obtained data and the evaluation of the effectiveness of methods for solving of this class of problems have been performed.
Influence of initial water temperature on the synthesis of gas hydrate by the method of explosive boiling liquefied hydrogen-forming gas freon 134a in the volume of water
Authors: Meleshkin A V , Glezer V V 
Published: December 2019

Abstract
The paper presents an experimental study of the influence of the initial temperature of water on the amount of gas transferred to gas hydrate. The studies were carried out at constant operating parameters, with varying water temperatures before decompression. This work is a continuation of the study of a method of synthesis of gas hydrates developed by the team of authors, based on the explosive boiling of liquefied hydrate-forming gas (Freon 134a) in a volume of water.
Experimental study of pine sawdust ignition in a vertical tube furnace
Authors: Kuznetsov A V , Butakov E B , Burdukov A P , Lomovskiy O I , Bychkov A L 
Published: December 2019

Abstract
The combustion processes of composite particles of powdered fuel from lignocellulose and coal have not been previously studied. It is planned that a non-obvious relationship will be established between the structure and properties of solid fuels obtained under various conditions of preliminary machining of individual fuel components and joint mechanochemical processing of fuel components before burning in the combustion chamber. Based on the data obtained, the description of both individual chemical and physical processes and complex mathematical models will be improved. In this paper, we investigate the influence of the structure and dimensions of a particles pine sawdust as one of the components of composite fuel on ignition and thermal decomposition.
Experimental study of heat exchange processes with variable operating modes of air heater-fan system
Authors: Mansurov R Sh 
Published: December 2019

Abstract
The variable modes of operation in the model heater-fan-room system were studied experimentally and analyzed. The relative excess heat is proposed as a dimensionless parameter in the analysis and rationing of experimental data. The analysis of its evolution was carried out with an abrupt change in the performance of the air heater and at a fixed fan performance; with an abrupt change in the performance of the fan and a fixed performance of the air heater. The regularities and main qualitative types of evolution of relative excess heat in the elements of the model system were revealed.
Utilization of heat and power complex with a capacity of 1 MW
Authors: Milman O O , Shifrin B A , Kuzina L A , Perov V B 
Published: December 2019

Abstract
The results of a compact and mobile heat recovery plant design based on the organic Rankine cycle (ORC) with a capacity of 1 MW, which can meet the gas pumping station auxiliaries in power, are presented. The choice of n-pentane as a working fluid, as the cheapest and most affordable on the market and providing condensation of exhaust steam at the atmospheric pressure, and thermal oil ‘Thermolan LT’ as an intermediate heat carrier has been substantiated. The choice of the work process parameters is focused on reliable long-term work with a minimum amount of maintenance. The plant is designed with the possibility to place its main units outside the technological zone of the main production. The design of the plant main components is presented. The turbine is axial, with five stages with a direct generator drive without a reduction gear. The turbine and generator are placed in a ventilated container. The steam generator is a vertically placed shell-and-tube heat exchanger. The air condenser is with horizontally arranged heat exchange tubes and screw-knurled fins. The recuperator is a shell-and-tube heat exchanger with horizontally arranged longitudinally finned tubes. It has been substantiated that for low-potential heat sources and in the conditions of low air temperatures, the use of heat-recovery plants based on the ORC is the optimal solution.
Effect of electric field on oxide layer structure at zirconium oxidation in H2O, CO2 and H2O/CO2 supercritical fluids
Authors: Shishkin A V , Sokol M Ya , Vostrikov A A 
Published: December 2019

Abstract
Oxidation of zirconium plates in supercritical fluids H2O, CO2 and H2O/CO2 was studied at 823 K and 24–39 MPa. An experimental cell was a flat capacitor, where the zirconium plate acted as the anode and the copper plate of the same size was the cathode. The interelectrode gap was 2 mm. The experiments were carried out in the absence of electric field and in the electric field of 300 kV m−1. It has been found that in all cases the oxidized layer consists of two parts: the outer loose layer and the inner dense layer forming an interface with Zr. At oxidation in a medium containing H2O, there is non-uniformity in distribution of oxygen near the boundary region of the loose and dense layers. When Zr is oxidized in the H2O/CO2 mixture, zirconium carbonate is found on the surface. In the electric field, an average specific rate of an increase in the sample mass decreases linearly with an increase in the fraction of CO2 in the H2O/CO2 mixture, and without the electric field it increases. Apparently, the reason for this is formation and subsequent decomposition of zirconium carbonate, leading to additional destruction of the oxidized layer and accelerated oxidation. When Zr is oxidized in CO2 in the presence of the electric field, a 12-fold increase in the rate of zirconium oxidation is registered, and this is associated with an increase in the surface leakage current due to formation of amorphous carbon.
Aerodynamic structure of a swirling turbulent flow in a vortex furnace
Authors: Salomatov Vas V , Salomatov Vl V 
Published: December 2019

Abstract
Insufficient study of the swirling flow structure, stability of high-temperature circulating zones, intensity of fuel and oxidizer mixture formation and other determining phenomena in the vortex furnaces indicates insufficiency of scientific substantiation of the methods for their calculation. Therefore, further detailed studies of aerodynamics of a turbulent swirling flow in a vortex chamber with intersection of the main flow by the inlet tangential jets aimed at the development of promising combustion devices seem to be relevant. The results of numerical simulation of the turbulent swirling flow aerodynamics with preference given to the modern models of turbulence and numerical schemes of high-order approximation are presented.
Calculation of temperature oscillations in thermal layer of regular solids at unsteady coefficient of heat transfer
Authors: Supel’nyak M I 
Published: December 2019

Abstract
The temperature oscillations in thermal layer of regular solids, caused by periodic oscillations of the ambient temperature and heat transfer coefficient, are analysed. A halfspace, a plate, a space with cylindrical channel, a cylinder, a space with spherical cavity are considered as solids. Exact solutions of the corresponding cyclic problems of heat conduction in the complex and real forms of trigonometric Fourier series are obtained. Methods of simplified solution of heat conduction problem based on boundary condition modification are considered. Comparison of exact solutions with approximate ones is carried out and the admissibility of the proposed approximate solutions is shown.
Development of acoustic and diffuse mismatch models for predicting the Kapitza resistance
Authors: Khvesyuk V I , Liu B , Barinov A A 
Published: December 2019

Abstract
This paper is devoted to the acoustic mismatch model and diffusion mismatch model of Kapitza thermal resistance. We consider that diffusion in the transition layer can be represented by variable composition and finite thickness instead of previous assumptions of a “black box” approximation. The effect of heat flow on the interface is reviewed in the acoustic mismatch model where energy is transferred between two different materials and the critical incident angles are taken into account. Finally we provide calculations of the Kapitza resistance for several interfaces (Metal-Sapphire and Metal-Silicon).
Estimation of the flows mixing efficiency inside T-micromixer with an external perturbation for low Reynolds numbers
Authors: Kravtsova A Yu , Ianko P E , Kashkarova M V , Bilsky A V 
Published: December 2019

Abstract
The flow pattern regimes and mixing quantities in case of an external perturbation for low Reynolds numbers in a T-shape microchannel were studied experimentally using the LIF technique. Formation of a hydrodynamic wave travelling along the outlet channel for the stratified regime was discovered. The wave amplitude is 0.057W
out. The wavelength corresponding to distance between two nearest pits is 3.86D
h. The change of mixing efficiency between undisturbed and perturbated flows in each of the considered sections is less than 6%. However, the arising of wave causes a decrease in the distance at which the flows are completely mixed.
Parameters of magnetron sputtering gas discharge plasma with a small anode
Authors: Sakhapov S Z 
Published: December 2019

Abstract
The plasma parameters of magnetron sputtering with a small cylindrical anode were investigated by electrical methods. Measurements of the current-voltage characteristics of the gas discharge were carried out. It is shown that changes in the operating modes of the magnetron are possible using an additional electrode of small size, to which a positive voltage is supplied from an independent source.
Plasma potential distribution around an infinite one-dimensional chain of dust particles
Authors: Salnikov M V , Fedoseev A V , Sukhinin G I 
Published: December 2019

Abstract
With the help of the code modification used in the authors previous works, the self- consistent distribution of density and electric potential are calculated around a one-dimensional infinite chain of dust particles. As a result, self-consistent distributions of the electric potential and space charge around a one-dimensional chain of dust particles, as well as the dependence of the dust particles charge on the interparticle distance, are obtained.
Numerical investigation of the pulsation frequency of the flow rate effect on the mixing efficiency of the active T-shaped micromixer
Authors: Shebeleva A A , Shebelev A V , Lobasov A S , Minakov A V 
Published: December 2019

Abstract
Flow patterns and mixing efficiency of fluids with different inlet flow rate pulsation frequencies in T-shaped micromixer were numerically investigated at Reynolds numbers Re = 100 and Re = 180. The flow rate pulsations were set sinusoidal with different frequencies of 0; 1; 10 and 50 Hz. The relative mixing efficiency means the mixing efficiency of active mixer regarding the mixing efficiency of an identical passive mixer without pulsations at the input; it was considered as the main value. The dependences of such value on the pulsation frequencies were obtained. It was found that active micromixers are much more efficient than the passive ones. Herewith, in the engulfment regime, the mixing efficiency increases twofold regarding the passive mixer, and in the region, before the onset of the engulfment regime, the mixing efficiency increases by about 170 times. In addition, it was found that the increase in mixing efficiency is almost independent of the frequency of pulsations.
Electric arc synthesis of titanium carbide nanoparticles
Authors: Smovzh D V 
Published: December 2019

Abstract
The structure of titanium carbide nanoparticles formed at electric arc spraying of composite Ti-C electrodes is studied. It is shown that the size of titanium carbide particles in condensation products varies in the range of 10–50 nm, crystal lattice of nanoparticles corresponds to TiC carbide. Annealing the material in an oxygen-containing atmosphere leads to carbon burnout and oxidation of titanium carbide nanoparticles. The main part of carbon is oxidized in the temperature range of 250–500°C, oxidation of titanium carbide nanoparticles occurs in the range from 320 to 400°C. When annealed to the temperatures of 1000°C, sintering of oxide TiO2 nanoparticles occurs. The proposed method can be used to obtain particles of titanium carbide with a shape close to the TiC crystal.
Thermal conductivity and thermal diffusivity of the melt Bi-Pb-Sn-Cd at high temperatures. computer experiment
Authors: Barbin N M , Tikina I V , Terentyev D I , Alekseev S G 
Published: December 2019

Abstract
The method of thermodynamic simulation is used to determine the thermal diffusivity and the thermal conductivity of the melt 42 mass.% Bi-40.6 masses.% Pb-10 Macc.% Sn-7.4 mass % Cd depending on temperature. It was found that the thermal conductivity and thermal diffusivity of melts Bi-Pb-Sn-Cd, Bi-Pb-Sn, Bi-Pb differ by no more than 15%. The obtained values indicate the prospects of using this melt as a coolant.
Experimental study of the titanium nickelide thermophysical properties complex
Authors: Samoshkin D A , Kozlovskii Yu M , Stankus S V 
Published: December 2019

Abstract
The article presents new experimental data on the thermal diffusivity (a), thermal conductivity (λ), heat capacity (Cp
) and linear thermal expansion coefficient (α) of titanium nickelide (56.6 wt. % Ni, 43.4 wt. % Ti). The temperature interval from 293 to 872…962 K has been investigated by laser flash technique, method of differential scanning calorimetry and dilatometric method. The estimated errors of the received data were 2–4%, 3–5%, 2–3% and (1.5–2)×10−7 K−1 for a, λ, Cp
and α, respectively. The approximation dependences and the reference table of investigated transport, caloric and thermal properties have been obtained.
Mathematical modeling of ice melt during irradiation by selective source of thermal radiation
Authors: Sleptsov S D , Savvinova N A , Grishin M A 
Published: December 2019

Abstract
A numerical simulation of the melting of an ice layer on a vertical substrate heated from a radiation source in the form of a halogen lamp in the single-phase formulation of the Stefan problem was carried out. Ice is presented in the form of a pure, non-scattering, selectively absorbing material with two spectral bands of bulk absorption. The computational model takes into account the selective nature of the radiation source. Analysis of the calculation results shows the dominant effect of the incident radiation on the formation of the flux density field of the resulting radiation in the medium. Comparison of the results shows a satisfactory agreement with experimental data.
Experimental investigation of the high-temperature air heating effect on the model artificial gas combustion process
Authors: Filippov P S , Khudyakov P Y , Ryzhkov A F 
Published: December 2019

Abstract
A description of the experimental rig is presented. The effect of combustion air high-temperature (up to 800°C) heating on the model artificial gas combustion process is described. The model artificial gas is a CO-N2 mixture. A comparison of the premixed and diffusion flame lower explosive limits is carried out. Experimental data are compared with open access published data of production of artificial gas-fired CCPP.
Effect of uniform crystal rotation on convective and radiation-convective heat transfer in the Czochralski method
Authors: Mitin K A , Berdnikov V S 
Published: December 2019

Abstract
The conjugate heat transfer in different regimes of heat transfer in the system “crystal – environment – walls of the growth vessd”, geometrically similar to the simplified scheme of the upper part of the thermal node in the Czochralski method, is studied numerically by the finite element method. The system of equations of thermo-gravitational and mixed convection in variables of vortex, stream function and temperature is solved. In addition, the uniform rotation of crystals is taken into account. Calculations are carried out at convective and radiation-convective heat transfer with fixed crystal length. Calculations of radiation fluxes are carried out on the basis of the zonal method under the following assumptions: the calculated area is limited by a closed system of surfaces; all surfaces of the system are grey, diffuse- emitting and diffuse-reflecting; the surfaces are divided into zones within which the radiation properties and temperature can be considered constant; the medium filling the growth chamber is diathermic. The calculations were performed with the Prandtl number equal to 0.68 (argon) and the Grashof number of 16000, typical of the real process. The effect of uniform crystal rotation from 1 to 25 rpm on radiation-convective heat transfer is studied. It is shown that under the action of rotation the spatial form of convective flows loses stability. Secondary vortices appear. As a result, the cooling efficiency of the crystal increases significantly.
Rayleigh–Benard convection in a gas-vapor medium at the temperature close to the critical temperature
Authors: Palymskiy I B , Fomin P A , Li You-Rong , Wu Chun-Mei 
Published: December 2019

Abstract
In this paper, we propose a new physico-mathematical model for the Rayleigh–Benard convection in a gas-vapor mixture of oxygen and cyclohexane, for which the temperature dependence of density has a maximum. Linear stability analysis was performed; two limiting cases where the inversion parameter tends to its limiting values are studied analytically. Formulas are obtained for the growth increment and decay, the neutral curve, and the boundary of the instability region in the wave plane.
Influence of the liquid chladone film on condenser heat transfer in the refrigeration unit
Authors: Sazhin I A 
Published: December 2019

Abstract
In this article, the effect of the thickness of chladone film on heat transfer in the condenser tube of a refrigeration unit is determined. The thickness of the liquid film is determined by the Lockcard-Martinelli and Fulford methods. With an increase in the film thickness of the liquid phase of R22 and R-134a refrigerants, the value of the heat transfer coefficient decreases in a selected range of changes in the refrigerant gas content. A comparison with the results of experimental studies is made.
Environmental Performance and Carbon Emission Disclosures: A case of Indonesian Manufacturing Companies
Authors: Yanto H. , Rofiah A , Bahlawan Z A S 
Published: December 2019

Abstract
Having population more than 250 million, Indonesia is among countries with high carbon emissions. As industry sector of this country contributes significantly to carbon emissions, the Ministry of Environment and Forestry of Indonesia requires companies to implement PROPER—a program to control negative impacts of companies’ operations on environment. The objective of study is to identify the impacts of PROPER on carbon emission disclosure. Environmental performance measured by PROPER has five levels i.e. black, red, blue, green, and gold. Black is considered the lowest rating with score 1 and gold is the best performance with score of 5. The study employs 18 indicators suggested by Carbon Disclosure Project (CDP) to measure carbon emission disclosure. These indicatorsare classified into five categories i.e.climatechange, green housegas, energyconsumption, reduction and cost, and accountability of emission carbon. By using purposive sampling, this study collects data from 100 manufacturing companies listed on IDX. On average manufacturing companies earn blue rating with carbon emission disclosure reach the percentage of 21%. PROPER rating positively and significantly affectseach category of carbon emission disclosure. The government and related parties need to facilitate these companies to improve their environmental performance and carbon emission disclosure.
The Development of gluten and eggs-free Cookies Enriched with Canna edulis flour rich in Resistant Starch Type 3 as a Functional
Authors: Nugraheni M , Sutopo  , Purwanti S , Handayani THW 
Published: December 2019

Abstract
This research aims to determine the gluten and egg-free cookies enriched with Canna edulis flour rich in resistant starch type 3 based on sensory characteristics, chemical composition, and physical properties. The research method was done with cookies formulation based on the amount of Canna edulis flour rich in resistant starch type 3 and a control (wheat flour cookies). The selected cookies based on a hedonic test with 80 semi-trained panelists was Formula I. The value of sensory characteristics were: aroma 7.56 ± 0.65; color 7.56 ± 0.65; taste 7.56 ± 0.73; texture 7.75 ± 0.49; overall acceptance 7.63 ± 0.60. The chemical composition were: moisture content 3.69 ± 0.17%; ash 4.20 ± 0.53%; fat 32.67 ± 0.15%; protein 11.15 ± 0.13%; carbohydrate 28.36 ± 0.60%; soluble fiber 0.80 ± 0.01%; insoluble fiber 24.81 ± 0.10%; resistant starch 3.36 ± 0.08%; amylose 13.80 ± 0.03%; amylopectin 12.88 ± 0.34%; energy 452.07 ± 0.87 cal. The physical characteristics were: weight 1.11 ± 0.02 g; diameter 31.47 ± 0.20 mm; height 3.77 ± 0.09 mm; spread ratio 8.34 0.22 ±, hardness 8.41 ± 0.56 N/kg. The selected cookies can be used as a functional food for people who are sensitive to gluten and eggs.
Designing an Information System Model of Academic Service Based on Customer Relationship management at University
Authors: Prima W , Ganefri  , Krismadinata  , Saputra R 
Published: December 2019

Abstract
This research aims at developing an information system model of academic service based on customer relationship management at university. This research is a research and development (R&D) through Borg and Gall design. This research only focuses and discusses on design stage. The result of this research shows that there are 4 primary supports (portfolio analysis, customer intimacy, determining services strategy, and evaluation) and 4 secondary supports (facilities and infrastructure, lecturers and professional staffs, academic information system website, and book for supporting model). Based on result of this research, it can be said that a information system of academic service model that has been designed effectively can be applied to improve academic service because it is based on practical theories that have been developed.