bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incipience of the intensive heat transfer regime at cooling high-temperature bodies in subcooled liquid
Authors: Kanin P K , Yagov V V , Zabirov A R , Lexin M A 
Published: November 2021

Abstract
Cooling in film boiling is usually an unwanted process in many technologies due to low intensity of heat transfer. Thus, predicting the solid wall superheat at vapor film destabilization is useful to avoid this phenomenon. In the present paper, two new semi-empirical models for evaluation of the wall superheat at destabilization of vapor film around the metallic body cooled in saturated or in subcooled liquid are proposed. Both models with fitted empirical multipliers are in good agreement with an experimental dataset. To evaluate the contribution of the natural convection in the model for temperature head at cooling in subcooled liquid, a problem about the natural convection near the vapor film, occurring during film boiling along the vertical plane, is numerically solved by means of ANES20XE CFD-code. The computational results of longitudinal velocity are in good agreement with the theoretical velocity of natural convection used in the model.
Features of cooling bodies with a high coefficient of thermal effusivity in subcooled mixtures
Authors: Zabirov A R , Molotova I A , Ryzantcev V A , Gubanova T A , Yagov V V 
Published: November 2021

Abstract
The paper focuses on the study a special type of boiling, "microbubble boiling". Experiments are carried out on water-ethanol mixtures of different concentrations. The pressure varies from 0.1 to 0.3 MPa; and copper and stainless-steel samples are used as working samples. The purpose of the experiments is to investigate the effect of such parameters as solid and liquid properties and subcooling on the transition temperature from the stable film boiling to “microbubble” boiling regime. In the course of direct comparison of the results obtained by cooling the samples with different thermal effusivity under the same conditions, a strong influence of the properties of the cooled body on the quenching process has been revealed.
Mathematical modelling of a staged pulverized coal gasification using O2/CO2 mixtures
Authors: Donskoy I G 
Published: November 2021

Abstract
Conversion of pulverized coal in a two-stage gasifier is studied. When considering carbon capture power plants, mixtures of oxygen with carbon dioxide may be used as a gasification agent. Carbon dioxide is a gasification agent, so characteristics of the gasification process change significantly compared to gasification in oxygen-nitrogen mixtures. The conversion efficiency is determined by the thermophysical factor (change in the heat capacity of the gas mixture and transfer coefficients) and the concentration factor (increase in the concentration of the gaseous reagent). The ratio of primary and secondary fuel consumption determines the leading stage of the process. The influence of process efficiency on oxygen concentration is estimated in the range of 21–30 vol. %.
Numerical modeling of subsonic axisymmetric reacting gas flows
Authors: Peskova E E 
Published: November 2021

Abstract
A numerical algorithm is developed and implemented for modelling axisymmetric subsonic reacting gas flows based on a previously created program for plane flows. The system of Navier-Stokes equations in the low Mach number limit is used as a mathematical model. Calculations of ethane pyrolysis for axisymmetric and plane flow of mixture at heat supply from the reactor’s walls are carried out. Through the interplay of the developed code and the code for plane flows it becomes possible to identify the geometric factor role at the presence of a large number of nonlinear physicochemical processes. We found that diffusion of synthesized molecular hydrogen mainly influences heat supply from the reactor’s walls to gas and pyrolysis products distribution along its length.
Numerical Simulation of 3D Flow over a Circular Cylinder
Authors: Kusyumov A N , Kusyumov S A , Mikhailov S A , Romanova E V 
Published: November 2021

Abstract
Unsteady 3D flow over a circular cylinder at Reynolds number of 3900 is studied numerically using the Navier-Stokes equations. Two formulations of the problem were considered: with boundary conditions corresponding to the flow around an isolated cylinder and with periodic boundary conditions to the flow behind a parallel circular cylinders grid. A comparative analysis of the integral and distributed characteristics of the flow around the cylinder and the spectral characteristics of the flow for both formulations of the problem is carried out.
Effect of the THF molecules on the hydrate cavities formation with adding NaCL molecules into the modeling system
Authors: Bozhko Y Y , Zhdanov R K , Getz K V , Belosludov V R 
Published: November 2021

Abstract
In this work, using molecular dynamics methods by Gromacs package we simulate the hydrate formation in systems containing THF, water, and NACL molecules at different thermodynamic conditions and concentration of THF molecules. The curves of the number of hydrogen bonds are obtained depending on the simulation time at different temperatures. The computer simulations results show that the hydrogen bonds between THF and water molecules are relatively weak, with a maximum number of two water molecules hydrogen bonded to THF, but THF can facilitate water molecules rearrangement to form a pentagonal or hexagonal planar ring that is the part of clathrate cavity. In addition, the THF molecule can significantly increase the likelihood to form clathrate cavities suitable for the second guest molecule. The effect of THF molecules concentration on the hydrate cavities formation with adding NaCL molecules into the modeling system is shown. In this work, data are obtained on the magnitude of torsion angles, the percentage of which increases depending on the simulation time, which allows concluding that labile large and small cavities of sII hydrates are formed. The increase in the THF molecules concentration is shown to lead to a decrease in the hydrogen bonds number of water molecules in the simulated system.
Application features of micro-pixel avalanche photodetectors in the laser Doppler anemometers
Authors: Rakhmanov V V , Dvoynishnikov S V , Meledin V G , Pavlov V A , Semenov D O 
Published: November 2021

Abstract
The optical receiver is an essential part of any laser Doppler anemometer. Traditionally, vacuum photomultiplier tubes are used for reliable reception of weak optical radiation. However, this type of photodetector has its own drawbacks, which lead to a design complication and an increase in the cost of LDA. In this work, the characteristics of silicon micropixel avalanche photodiodes are investigated and the operation of a silicon photomultiplier as a photodetector in an LDA is tested when measuring the velocity on test benches. The possibility of using Si-PMT to receive optical signals of the laser Doppler anemometer is shown.
Geometry Monitoring of Rotating Parts of Power Unit with an Adapted Doppler Preprocessor
Authors: Kulikov D V , Dvoynishnikov S V , Rahmanov V V , Pavlov V A , Kabardin I K 
Published: November 2021

Abstract
Current work is devoted to the development of a device for monitoring the dynamic shape of a power unit. The work is based on the FMCW method. The light source uses a low-coherence semiconductor laser diode. Signal processing is performed on an adapted Doppler processor. The paper describes the methods, hardware and signal processing algorithms.
Developing the laser doppler anemometry method for the diagnostics of kinematic parameters of a turbulent flow in the near wall region
Authors: Meledin V G , Dvoinishnikov S V , Kabardin I K , Chubov A S , Bakakin G V , Kabardin A K , Pavlov V A , Pravdina M Kn , Yavorsky N I 
Published: November 2021

Abstract
The aim of the work is to develop a laser Doppler anemometry method for diagnosing turbulent aerodynamic flows in the near wall region. This will enable measuring two projections of the velocity vector in the range of 0.001 … 400 m/s with a relative error not exceeding 0.1%. The measurement area is 0.1×0.1x0.5mm. The positioning device allows moving the measuring unit in the area of 250×250x250 mm with an accuracy of 0.1 mm. This method also provides the ability to measure local flow rate fluctuations.
Thermodynamic modeling of melt of the Bi-Pb-Sn-Cd system
Authors: Barbin N , Tikina I , Terentyev D 
Published: November 2021

Abstract
Thermodynamic modeling of heating of the Bi-Pb-Sn-Cd system in a wide temperature range is performed in the TERRA software package. The equilibrium constants of thermal dissociation reactions are determined. The equilibrium constants of thermal dissociation reactions for metal compounds formed in the Bi-Pb-Sn-Cd melt as a result of heating are determined: BiPb, PbSn, SnBi, Pb3Bi, Pb5Bi4Sn4, PbSn3, Bi2Sn3, Bi7Pb, CdSn, Sn3Bi, PbBi2Sn2, Pb3Bi4, Cd3Bi2, Bi7Pb3, Sn4Bi2.
Investigating the adhesive properties of polymers for 3D printing
Authors: Vendland L E , Volkov-Muzylev V V , Demidov A N , Pugachuk A S 
Published: November 2021

Abstract
The article presents the research of adhesive properties of various polymers used in additive manufacturing by fused deposition modeling. Tensile tests of additively manufactured samples of various polymers are carried out, electro-microscopic photographs of the working area are taken before and after tests, and studies on the manufacturability of printing are performed to exclude further typical errors identified during these tests. Samples of the following polymers are studied: thermoplastic resin acrylonitrile butadiene styrene (ABS +), thermoplastic resin acrylonitrile butadiene styrene with the addition of titanium nitrite as a dye (ABS + TiN), thermoplastic resin acrylonitrile butadiene styrene with the addition of polyester inserts (ABS polylactide (PLA), polylactide based compound (PLA HP), thermoplastic polyethylene terephthalate glycol (PETG), and nylon with carbon inserts (NSC). The work reveals the advantages and disadvantages of the investigated plastics. For example, deformations occur when the part is cooled down during printing process of ABS +, and a crack could form in stress concentrators as a result of the influence of cold air flows.
The analysis of the level of emission characteristics depending on the aerosol structure
Authors: Vasilev A Yu 
Published: November 2021

Abstract
An attempt to combine the main verified recommendations for the organization of low-emission combustion of fuels (in relation to three main components of standardized harmful substances SN, NOx, and CO2) into one of the crucial modern problemsis implemented. Thepaper is devoted to the search for some general trends in the formation of emission characteristics based on the accumulated experience such as computational and experimental results obtained in CIAM.
Analysis of the cladding melt relocation along the surface of the fuel pin with help of the SAFR module
Authors: Usov E V , Lobanov P D , Klimonov I A , Sycheva T V , Chuhno V I , Butov A A , Kudashov I G 
Published: November 2021

Abstract
The presented work is dedicated to the development of approaches to simulate cladding melt relocation along the surface of the fuel pin. Development of the approaches is based on the results of the experiments carried out at the NSI RAS and IT SB RAS. Features of the melt relocation are studied in the experiments. It is demonstrated that the laminar film flow regime in the heated part of the fuel simulator is the main flow regime. Model of the melt relocation is constructed. This model is the part of the SAFR module of the EUCLID/V2 coupled code. It is shown that the proposed approaches allow simulating the melt relocation with good accuracy.
Long-term and seasonal anomalies of the Sea of the Azov thermohaline structure for 1913 – 2018
Authors: Shukalo D M , Shul’ga T Ya 
Published: November 2021

Abstract
Variability of temperature and salinity as well as quantifying global trends are fundamental for understanding changes in the Earth's climate. In current paper, a long-term variability of the hydrological regime of the Sea of Azov for 1913–2018 is studied. On the basis of oceanographic information, the seasonal variability of temperature and salinity by the areas of the Sea of Azov is analysed. Temperature anomalies have been revealed, periods of salinization and desalination of the Sea of Azov have been noted and linear trends of the anomaly have been obtained.
Calculating the effective thickness of the thermal barrier coating
Authors: Lukashov V V , Naumkin V S 
Published: November 2021

Abstract
The paper presents the results of numerical simulation of heat transfer at the interaction of a hot impact nitrogen jet with a ceramic thermal barrier coating 7YSZ based on ZrO2 with the addition of 7% Y2O3. The radiant component of heat transfer is shown to make a significant contribution to the final temperature distribution on the surface of the protected product.
The Effect of UV Irradiation on Tensile Strength of Polypropylene Reinforced Kenaf Fiber and Peat Soil
Authors: Joharudin Nurul Farahin Mohd , Mustapa Mohammad Sukri , Supawi Aiman , Latif Noradila Abdul , Hussin Wan Nasrul Nizam Wan , Alias Mohd Fairuz , Kamarudin Kamarul-Azhar , Ariffin Ahmad Hamdan , Yusof Farazila 
Published: November 2021

Abstract
Nowadays, natural fiber polymer composites have been widely used in many industries and applications because of their low cost, renewable and eco–friendly. However, exposing this material to the outdoor environment will affect the material properties as it is exposed to various situations such as ultraviolet exposure, raining, etc. This paper studies the degradation of kenaf fiber, polypropylene strengthened with peat soil combustion at 600ºC upon ultraviolet exposure. The wood–plastic composites (WPCs) produced into two batches, kenaf fiber mixing with polypropylene and kenaf fiber and peat soil mixing with polypropylene. All the specimen has exposed in ultraviolet (UV) irradiation at 0 hour, 100 hours, and 200 hours, respectively. The UV irradiation accelerated weathering tester machine was conducting the water spray cycle, which is 4 hours of water spray and 8 hours without water spray continuously until achieved the target time. The finding obtained from the tensile test, the composition with the highest contain of kenaf fiber in a polymer composite, has the lowest tensile strength after exposed with 200 hours of UV irradiation, which is 20.23 MPa. While the adding peat soil as reinforcement has shown the increasing the percentage of tensile strength after 200 UV exposure.
Efficiency improvement of solar cells by CaAlSiN3:Eu2+and Y2O3:Eu3+phosphors
Authors: Huang Shaoqiang , Lou Chaogang , Diao Han , Wang Zhaoyong , Yin Yunzhen 
Published: November 2021

AbstractCaAlSiN3:Eu2+(CASN) and Y2O3:Eu3+(YO) phosphors are mixed into ethyl vinyl-acetate (EVA) to form luminescence down-shifting (LDS) films which are used to improve crystalline silicon solar cells by converting the photons with the wavelength from 200 nm to 500 nm into red light. Experimental results show that the conversion efficiency of the solar cells is enhanced from 19.61% to 20.00%. The improvement is better than that with only CASN phosphors in EVA films. The reason is the high quantum yield of YO phosphors in the wavelength range 250 nm-350 nm, which offsets the poorer performance of CASN phosphors in this wavelength range.
A Demodulation Circuit For Analog Front End Of Passive Tag Chip
Authors: Li Qinglong , Xu Yong , Li Qiao , Peng Kun , Zhang Xian 
Published: November 2021

Abstract
The demodulation circuit designed in this paper is suitable for the analog front end of passive UHF RFID tag chip, which can handle ASK signals with large changes in amplitude, modulation depth and signal frequency. Its performance meets the requirements of standards ISO/IEC 18000-6C and GB/T 29768-2013. Envelope detection circuit and limiter circuit are simple in structure and do not consume power. The comparison reference voltage is taken according to the average value of the envelope high and low levels, and is less affected by the dynamic changes of the input signal. Changing the width-to-length ratio of the MOSFETs in the feedback path of the comparator can adjust the hysteresis, with strong noise suppression and controllable sensitivity. The demodulator is implemented with TSMC 0.18 μm standard CMOS process. The simulation results show that the ASK signal modulation depth that the demodulator can handle is as low as 30%, and the maximum pulse width demodulation error is only 0.43%.
Research on Thermal Fatigue Life Prediction Technology of PoP Laminated BGA Products
Authors: Ran Hong-lei , Sheng Xiao-jie , Duan Qiang , Zhang Kui , Huang Jie 
Published: November 2021

Abstract
In this paper, a fast prediction method for thermal fatigue life of PoP laminated BGA Product was proposed. Firstly, the stress and strain of the solder joints of each layer of the laminated device in thermal fatigue test was determined by finite element simulation method. According to the research idea of relative stress and strain, the solder joints were divided into sensitive solder joints and reliable solder joints. Secondly, sensitive solder joint were connected with PCB traces through the internal pads, bonding wires, TSVs and reliable solder joints to form a daisy chain. Through real-time dynamic monitoring of the resistance change of the daisy chain in thermal fatigue test to judge whether the solder joints fail, and record the occurrence time of the first failure solder joint. Finally, the thermal fatigue life of the product was estimated by the Norris-Landzberg formula.
Influence of Noise on Fault Diagnosis of Transformer based on Vibration Signal
Authors: Chen Ming-hao , Zhou Quan , Ou Yangxi 
Published: November 2021

Abstract
Monitoring transformer vibration signals is a universal application method to realize the diagnosis of internal mechanical faults of transformers. However, the actual transformer operating is interfered by the noise of the surrounding electrical equipment, which reduces the accuracy of the vibration signal identification. This paper simulate the typical noise sources in the actual transformer operating environment, including fan noise and surrounding equipment fault noise, and explore the impact of different noise sources on the transformer vibration signal.
Analysis of the Response of a Static Reactive Power Compensator to Instability and Failure in Electrical grids
Authors: Maridueña Víctor Manuel , Castro Edwin Arnaldo , Layedra Nelson 
Published: November 2021

Abstract
The reliability of electrical power systems has led to the implementation of new equipment with reliable technology to solve transient failures, in recent decades flexible AC transmission systems (FACTS) have been implemented in power grids, resulting in high levels of stability and control. One of the elements used is static VAR compensators (SVC), however there is very little information about the dynamic response of the device to network instability and electrical failures, for which Simulink analyses the response of the SVC. The device consists of a 47.1 MVar reactive power compensator and a 97.6 MVar inductive reactivator compensator, implemented in a three-phase 500 kV system. The results indicate the effectiveness of response against network instability while maintaining the stable voltage of the network, but against electrical failures the type and time of failure must be considered. In the case of phase-phase faults, the response of the SVC is limited with drops of 0.52 pu.
Rock Image Intelligent Classification and Recognition Based on Resnet-50 Model
Authors: Liu Jinzi , Du Wenying , Zhou Chong , Qin Zhiqing 
Published: November 2021

Abstract
Machine learning algorithms becomes popular for intelligent classification of rock images. In this paper, it selects Resnet 50 neural network model to divide the data sets based on the rock pictures taken under the white light lamp. By continuously adjusting the parameters of each layer, the intelligent classification of rocks is carries out. The training final validates accuracy reached 94.12%.
Research on method of mitigating instability of wind power generation system based on hydrogen production
Authors: Chen Mengping , Ren Jianxing , Li Fangqin , Sun Haijie , Wang Ze 
Published: November 2021

Abstract
Intermittent power generation of renewable energy power generation system is the active reason affecting the stability of power grid, and adjusting the load imbalance between power generation and power supply through hydrogen production unit is the main means to reduce the impact of natural conditions and ensure continuous and stable power supply. In this paper, the simulation model of permanent magnet direct drive fan system for hydrogen production load is established, and the permanent magnet direct drive wind power generation unit is used to supply power to hydrogen production load to achieve the effect of stable output power.
Performance Characteristics of Epoxy Modified Open Graded Friction Course (OGFC) By Post-doping Methods
Authors: Zhang Linyan , Ma Yong , Zhao Yanbin , Li Bo , Li Peifeng , Xie Bin , Feng Jiliang 
Published: November 2021

Abstract
To improve drainage properties and increase driver’s safety in wet weather, epoxy modified Open Graded Friction Course (OGFC) by post-doping methods was proposed. The predominant focus of this paper evaluated the performances of epoxy modified Open Graded Friction Course (OGFC) such as rutting resistance at high-temperature, crack resistance at low temperature, friction, moisture resistance and coefficient of permeability. For comparison, the same NMAS Open friction course with epoxy asphalt which was supplied courtesy of ChemCo Systems Ltd and SK High-Viscosity Asphalt were cited. In addition, the harsh construction requirements and application limitations caused by the residence time of epoxy asphalt were solved by the post-mixing process which was produced by two steps, First step, component B of epoxy asphalt was produced in the backyard plant, then suitable amount of component A was added and mixed evenly while paving in site, affecting the holding time only in the two links of paving and rolling, and the time was easy to control. The results show that epoxy modified Open graded friction Course reinforced with Basalt fiber produced by post-mixing methods has good friction resistance and permeability while retaining satisfactory performance and mechanical properties.
Progress of high temperature polybenzimidazole proton exchange membrane: a systematic review
Authors: Liu Guanghan 
Published: November 2021

Abstract
Proton exchange membrane (PEM) is the core component of proton fuel cell. Generally speaking, ordinary PEM has the poor barrier to fuel (especially liquid fuel) and proton conduction has a strong dependence on water molecules. Compared with ordinary PEM, high temperature fuel cell works in high temperature non-water environment, which overcomes the above problems. Besides, the system is complex with low impurity and much simpler flow field design. Polybenzimidazole (PBI) not only meets the requirements of high temperature, but also has higher proton conductivity than ordinary PEM, i.e., is the best material for high temperature PEM. From this point of view, the properties and fabrication of PBI are systematically reviewed. Specifically, the factors influencing the performance of acid doped PBI high temperature PEM as well as existing problems (high temperature degradation as well as chemical oxidative degradation) are demonstrated. Furthermore, the corresponding solutions and future direction are put forward.