bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Closure Coefficients of K-Ω SST Turbulence Model on Predicting Stall Characteristics of The Airfoil
Authors: Liang Changping 
Published: August 2020

Abstract
The two-dimensional numerical simulation for NACA0015 airfoil and S325 airfoil were conducted with k-ω SST turbulence model. For the k-ω SST turbulence model could not predict the airfoil stall characteristics accurately, the non-equilibrium turbulence transport nature was systematically analyzed. The study showed that: the turbulent viscosity scope simulated by the original k-ω SST turbulence model was smaller which resulting in the model could not accurately simulate the turbulence transport properties in the separation zone; By increasing β* or decreasing α1 can improve the capabilities for predicting the transport characteristics of non-equilibrium turbulent, and then improve the accuracy of numerical simulation for stall characteristics of the airfoil, it also helps to improve the accuracy of numerical simulation of wind turbine blades.
Study on Calculation of the Buoyancy Drag Coefficient in the High-Speed Wind Tunnel Test
Authors: Chen Xuekong , Wei Zhi , Liu Guangyuan 
Published: August 2020

Abstract
In order to obtain the drag coefficient in accuracy, it needs to correct the model’s buoyancy drag coefficient in the high-speed wind tunnel test. However, there are several methods on calculating the buoyancy drag coefficient, each will generate a result differently. Three types of methods are studied in this paper, the formulas are derived, the buoyancy drag coefficients are calculated, and the results are compared in the end. It shows that the most exact method is the one based on pressure fitting function, it’s suitable for correcting the model’s drag coefficient with high accuracy requirement.
Simulation of temperature field of A356 aluminum alloy in freeze casting
Authors: Yang Haoqin , Shan Zhongde , Wang Yifei , Liu Limin 
Published: August 2020

Abstract
In this paper, the temperature change curve of the casting and frozen sand mould during the solidification process of the A356 aluminum alloy in the frozen sand mould is tested. According to the actual temperature change curve of the casting surface and the sand mould surface, the interface heat transfer coefficient between the frozen sand mould and the A356 aluminum alloy could be reversed analysis. The results show that when the casting temperature is lower than 550 °C, the interface heat transfer coefficient remains about 750 W.(m2.K)-1; When the casting temperature is between 550 °C and 610 °C, the interface heat transfer coefficient increases significantly; when the casting temperature is higher than 610 °C, the interface heat transfer coefficient reaches the maximum value, which is about 2300W. (m2.K) -1. At this time, this study simulates the solidification temperature field of aluminum alloy hub parts in the frozen sand mould according to the interface heat transfer coefficient calculated by inverse analysis, and the temperature field of resin sand mould casting was used as for comparison. The results show that: under the same solidification time, the temperature field of A356 aluminum alloy hub parts in frozen sand mould is lower than that of resin sand casting, freezing casting can realize the high-speed solidification process of different parts of complex castings.
Experimental study on heat transfer characteristics of flow on an inclined hot metal plate
Authors: Xiong Muwen , Zhang Jiaqing , Wang Qing , Zhao Senlin , Wang Guanjian , Wen Pei , Han Jiao , Shi Xiangjian 
Published: August 2020

Abstract
In order to deeply understand the heat transfer characteristics of water and foam at high temperature with different inclination angles and initial surface temperature, pure water and foam were selected to conduct experimental research on high temperature surface liquid flow with inclination angles of 45 ° and 70 ° and initial surface temperature of 110 ° C, 210 ° C, and 310 ° C. It is found that the difference between the flow pattern and heat transfer of pure water and foam on the surface of high temperature metal plates is more obvious when the surface initial temperature is higher. The water flow form horseshoe-shaped low temperature region with the lateral width increasing and the longitudinal length decreasing on the higher temperature surface. The foam on the high-temperature surface is mainly cooled by the strip shaped area flowing in the mainstream direction; the length of the cooling area covered by the foam of the high-temperature surface is significantly longer than pure water.
Numerical simulation of micro-nano bubble central intake aeration
Authors: Rong Xiaojie , Wang Qi , Ren Liuyi 
Published: August 2020

Abstract
In this paper, ANSYS FLUENT was used to simulate the gas-liquid two-phase flow in the process of micro-nano bubble aeration and optimized the central air intake aeration conditions. The particle size of microbubbles was 2 μm, the Eulerian model was used in multiphase flow model, and the standard k - ε model was used in turbulence model. The gas-liquid two-phase flow field with different aeration velocity was simulated. The effects of aeration time on gas holdup were studied. The results showed that the aeration effect was better with the increase of aeration speed, stronger turbulence, two-phase mixing and oxygen mass transfer.
Research on the Innovative Talents in “Double First-Class” Universities under Artificial Intelligence Technology
Authors: Song Wanying , Min Jian 
Published: August 2020

Abstract
With the continuous integration of artificial intelligence technology and management disciplines, the emergence of new technologies and new concepts put forward new requirements for the cultivation of cross-disciplinary talents in management disciplines. At the same time, strengthening the development of cross-disciplinary integration is also a vital part of the “Double First-Class” universities construction. This article points out that the application direction of artificial intelligence technology in innovative talents of management discipline can be divided into three levels: computational intelligence, perceptual intelligence, and cognitive intelligence. Based on the three levels, formulated innovative talents in the management discipline cross-cultivation model that integrates innovation quality orientation, innovation performance orientation and innovation contribution orientation, designed a talent training operation mechanism based on multi-subject collaboration, facing the new education ecology in the era of artificial intelligence.
Drag Prediction of Nasa Common Research Model Under Stochastic Inflow Conditions
Authors: Wu Xiaojun , Chen Jiangtao , Hu Xingzhi , Li Huan , Zhang Chao 
Published: August 2020

Abstract
Numerical investigations of NASA Common Research Model under stochastic inflow conditions are analysed in this paper by Non-intrusive Polynomial Chaos (NIPC) method. Reynolds number, Mach number and temperature of inflow conditions are assumed to be independent stochastic variables. It is found that predicted drag mainly depends on Mach number of incoming flow. The contribution of Reynolds number and temperature to the variance of drag is negligible. The mean value of drag shows consistent convergence with grid refinement. The investigation of this paper quantitates the uncertainty induced by stochastic inflow conditions to drag prediction and recognizes the most significant input variable. This will help the validation of numerical methods with experiment.
Preliminary design of laboratory experiment on flow pattern in natural-like fish way ponds
Authors: Huang Zhigang 
Published: August 2020

Abstract
In the design of fish way, the flow pattern of the pool is an important design basis. Many factors need to be considered in the preliminary test of fish way in the laboratory. This paper introduces the design method and preliminary results of flow measurement test of fish way pond chamber. The results show that the layout and porosity of the partition wall should be considered in the design of natural fish way. Different partition arrangements and porosities have obvious influence on the flow pattern in the pool. In the flow pattern of the pool chamber, there is a clear main flow, but the flow rate is low behind the partition wall and near the side wall of the pool chamber.
A Second Order IMEX Method for Radiation Hydrodynamics
Authors: Zhao Yang 
Published: August 2020

Abstract
Radiation hydrodynamics problem is mulitphysics field coupled and challenge in mathematics. A new scheme, IMEX, is put forward in solving RHD equations when the explicit method have an extremely small time step and implicit method have a complicated and high cost solver. RHD equations are solving by splitting the explicit operator and implicit operator with IMEX scheme. The results of Riemann problems are plotted and the scheme shows the effect to lower the computation cost.
Experimental research on collector effect on operating characteristics of high-speed free-jet wind tunnel
Authors: Zhao Fang , Qing Honggang , Ren Zebin , Li Yi 
Published: August 2020

Abstract
Collector is one of the key parts of the high-speed free-jet wind tunnel, which directly affects the performance of wind tunnel. In this paper, a small high-speed free-jet wind tunnel is used as the test platform to carry out the start-up and operation characteristics test of wind tunnel. Start-up pressure characteristics were obtained at various Mach number, and the influence of the collector throat heights and collector positions on start-up pressure and matching pressure was preliminarily studied. The results show that the high collector throat height can meet the requirements of wind tunnel start-up and pressure matching. The closer the collector is to the nozzle, the smaller the corresponding starting pressure and matching pressure. However, this trend weakens with the decrease of Mach number, which lays a foundation for the development of large high-speed free jet equipment.
A mock circulation loop for in vitro haemodynamic evaluation of aorta
Authors: Li Xuhui , Li Zhenfeng , Chen Duanduan 
Published: August 2020

Abstract
Haemodynamic conditions play a crucial role in the pathological development of aortic dissection (AD). However, it is challenging to quantitatively and precisely capture the flow features in vivo. In this study, a mock circulation loop (MCL) embedded with patient-specific aortic phantoms was proposed. In order to evaluate perfusion characters, a normal aortic model and an AD model were established with twelve main branches. The system is capable of replicating the aortic geometry, vascular compliance, characteristic resistance, and peripheral resistance of the cardiovascular system. By altering controlling parameters, it can mimic various cardiovascular conditions. The physiological healthy rest cardiac condition was reproduced and the rationality and accuracy of the system was confirmed by comparing the measured flow data from the MCL with a normal aortic phantom and the in vivo ultrasound velocimetry of healthy volunteers (maximum discrepancy was 4.69%). Different flow features between the normal and AD phantoms were quantitatively compared by pressure sensors and ultrasonic flow sensors under the same condition. Therefore, the proposed MCL can be applied as a research tool for in vitro haemodynamic analysis of the aorta. Moreover, it can be applied to evaluate the performance of interventional devices and to provide a realistic platform for trainings on interventional treatments.
Study of a microfluidic chip with converse fluid
Authors: Song Feifei , Ma Yuting , Wu Yunliang , Wang Ce 
Published: August 2020

Abstract
The current microfluidic chip design generally forms a stagnation point in the exit flow area of the microfluidic chip. The presence of the stagnation area can cause problems such as choke of channel and sample purity degradation. For this problem, a microfluidic chip with converse fluid was designed. The converse sheath liquid can avoid the adverse effects caused by the presence of the stagnation point. It can prevent the cells from contacting the wall surface, and avoid the blocking problem of cell. At the same time, the introduction of the converse sheath liquid can also focus the sample flow in the sorting channel and the waste channel again, which is convenient for the detection of the sorted sample. The fluid flow state in this microfluidic chip was also simulated, and it verified the benefit of introducing converse sheath fluid, which has reference value for the design of microfluidic chip for cell analysis and sorting.
Numerical Simulation for Creep Characteristics of Soft and Hard Interphase Rock Mass
Authors: Han Bing , Fu Qiang , Wang Chunyan 
Published: August 2020

Abstract
By using the simulated software FLAC3D, triaxial creep simulation experiments are conducted on soft and hard interbedded rock bodies under different stress levels and loading paths, and the effects of stress state and loading method on the time-dependent characteristics of soft and hard interbedded rock bodies are studied. The established model is analyzed with the method of 3-D visco-elasto-plastic numerical simulation. The results have shown that under the same stress level the deformation and volumes of plastic zone of rock mass will expand when the amounts of soft rock layers increase or the gradient of soft rock layers is steeper.
Non-real eigenvalues of a class of fourth order discontinuous differential operators with indefinite weight function
Authors: Zhao Xin , Liu Dejun , Xu Xiaoli 
Published: August 2020

Abstract
The spectral theory of differential operators is one of the basic problems of differential operator theory. It has been an important tool in quantum mechanics and other fields. For the Sturm-Liouville Problems with weighted functions, the spectral theory of right-definite problems with self-adjoint boundary condition has been accomplished. But the spectral structure of indefinite problems, is quite different from and more complicated than that of right-definite problems. Compare with second order case, much less known for the fourth order indefinite differential operators. The present paper discusses a class of fourth order discontinuous differential operators. We obtained the estimate on the non-real eigenvalues, under separated boundary condition and the condition that weighted functions change signs for only once or any times.
Experiment of Measuring Half-wave Voltage and Electro-optic Coefficient of Crystal Based on KDP Crystal
Authors: Wu Yutong , Su Bo 
Published: August 2020

Abstract
The paper aims to measure half-wave voltage of KDP crystal irradiated by a 532 nm red laser. This paper explores a safe and easy way to measure the electro-optic coefficient, and then calculates the electro-optic coefficient of the KDP crystal. It provides a feasible way to measure the half-wave voltage and electro-optic coefficient of different electro-optic crystal materials by laser with different wavelengths.
Effect of the Angle of the Crossed Fibres of a Fog Harvester on its Collection Efficiency
Authors: Jia Zhen , Zuo Zhigang , Liu Shuhong 
Published: August 2020

Abstract
Although fog harvesting technology was firstly invented in the 1980s, the theoretical research is still in its infancy. To enhance the collection efficiency of fog harvester, lots of work have been done such as surface modification and 3D structure of the fibres of the fog harvester. In this study, based on observation of daily phenomenon, relationships between the angle of crossed fibres of the fog harvester between collection efficiency are discussed. Results show that as the angle of fibres changes, the effective collection rate per unit length of the fibre keeps unchanged, except near the maximum/minimum limits of the angle, where the collection rate drop significantly, caused by clogging according to the experimental observations. It is also found that the existence of fibre node will influence the collecting process of fog harvester, which can explain why harp-like fog harvester performs well in fog collection.
The Necessity to Assess the Electromagnetic Environment Near 5-G Radio-Emitting Objects with Instrumental Procedure
Authors: Zvezdina M Yu , Shokova Yu A , Prygunov A G , Palyanitsa A A , Sumin D L 
Published: August 2020

Abstract
The features of the new 5G standard if compared to the currently used 4G lie within a significant frequency range expansion, and the implementation of the Internet of things. They made it impossible to expand the existing safety standard of broadband cellular network construction in large cities to the new standard. Differences between the Western and Russian approaches to the maximum permissible power level assessment and the lack of publications on the subject prompt measurement experiments in order to obtain an approximate electromagnetic environment assess near radio-emitting objects. At the preliminary stage of the measurements, it is necessary to choose the right measuring instruments and procedures, since the choice determines the price-quality relationship of the experiment. In the paper the results of the analysis for the known measuring instruments are given with an account to the special requirements formulated according to 5G standard features. The conclusion on the availability of the measuring instruments with the required characteristics is made. It is shown that the experiment efficiency depends on the measurement area dimensions and the measurement points spacing. In case of reflector antenna of 0.9 m diameter operating at 6 GHz the number of measurement points can be reduced without a loss of accuracy if the measured antenna passport data as well as the recommendations given in the paper are taken into an account.
Solar-diesel hybrid power plant battery charging systems
Authors: Sau Matius , Patoding Hestikah Eirene , Kasa Agustina 
Published: August 2020

Abstract
This study aims to examine the charging current of a solar energy hybrid generator with a Genset / Diesel and the time used to fill the accumulator in conditions without load and load conditions. The results showed that the solar energy hybrid generator and Genset / Diesel prototypes were able to produce electrical power at 08.00 - 17.00 in the average sunny weather of 290.7 Wp without loading and at the time of load of 236.4 Wp. At night, the energy stored in the battery is converted into electrical energy to supply the load. Thus it can save electrical energy.
Study of microwaves energy conversion into electric current on semiconductor material NaxCuyTiz
Authors: Jayanti Regna Tri , Haryati Sri , Bustan M. Djoni 
Published: August 2020

Abstract
Converting microwaves energy into electric current has been studied through co-precipitation and sintering process on the semiconductor material. Most of the application of these methods still had a challenge of lowering the resistivity value of semiconductor material. Some researches indicated by adding molten salt into semiconductor material can reduce the resistivity value. In this study, the synthesis process by combining the co-precipitation and sintering method of transition metal (titanium and copper) and alkali metal (Sodium) shown an improvement in lowering resistivity problems. Composition ratio, temperature, and distance of radiation were the variable of measurement in this research. Three semiconductor materials NaxCuyTiz were synthesized by using 60 ml of hydrochloric acid (HCl) and 80 ml of ammonium hydroxide (NH4OH) as a reagent in co-precipitation method and sintering at temperature 500°C. An Olympus microscope was used to analyze the microstructures of all three materials. Fractions x, y, and z in the materials were determined by analysis of X-ray spectrograph model 2501. The resistivity values of three materials, namely as Na0.52Cu0.37Ti0.11, Na0.26Cu0.39Ti0.35, and Na0.26Cu0.67Ti0.07 were obtained by varying the temperature of measurement. The microwave radiation was measured by observing the output voltage and current along with the radiation at a variable distance (60, 90, 10, 150, 180, and 210 cm) through the semiconductor material. The experiment showed that material Na0.52Cu0.37Ti0.11 had low resistivity and small bandgap energy as 0.875 eV and able to convert microwave energy from 1.624 × 10−24 Watt to 9.137 Watt at 60 cm of microwaves radiation distance.
The effect of active carbon adsorbents from some wastes in reducing free fatty acids and acid number to improve vco quality
Authors: Simatupang Dimas Frananta , Tarigan Jenny , Mansyur  
Published: August 2020

Abstract
The use of several wastes such as durian outer skin, cassava outer skin and corncobs could be used to improve VCO quality. The wastes were converted into activated carbon as an adsorbent that was activated using sodium carbonate in purifying VCO in terms of reducing free fatty acid (FFA) and acid number. VCO used was oil that has made directly in the laboratory of oleo chemistry PTKI Medan and tested to reduce level of FFA and acid numbers. A total of 5 ml VCO samples were used to determine reducing in level of FFA and acid numbers by a titrimetric method with three times repetition using 0.1 N NaOH and previously treated with activated carbon adsorbent from durian outer skin, cassava outer skin and corncobs as much as 1 gr, 2 gr, and 3 gr. Based on the results of the examination, it was found that the level of FFA and acid number of VCO had a significant decrease with the best-activated carbon adsorbent using waste from cassava outer skin where level of FFA decreased by 0.16% and acid number decreased by 0.448.
Application of air conditioner (AC) automation system on arduino flatform-based vehicle
Authors: Randis  , Wijaya S H 
Published: August 2020

Abstract
This study aims to design and create a safety device and automation system in the use of air conditioner (ac) use in-vehicle units, especially in four-wheeled vehicles based on Arduino UNO microcontroller Atmega 328. The safety device system created in this study used Arduino UNO as its microcontroller, a tool was equipped with a PIR sensor that was positioned in the cabin and a limit switch placed at the door of the vehicle. If there are humans inside the vehicle unit, the PI sensor will detect movement, and if the unit door is in the closed position, the limit switch will be depressed. The principle used the AND logic gate principle where both inputs both the PIR sensor and the limit switch must work together to turn on the AC, but if only one input works, then the AC will not turn on. The results of this study indicated the tool could work under the design that has been done, and the programming of the safety device can work well according to the desired working principles through the programming commands on the Arduino UNO microcontroller.
Effect of Typical Lubrication on the Pressure Ratio Through Operating the EFI Suzuki Engine
Authors: Sihombing R , Hidayat  , Fatmawati A , Nur R 
Published: August 2020

Abstract
Many types of lubricants was used as a lubricant in the Suzuki Baleno EFI engine. There is some questions in the community which better lubricants are used without prior research. This paper aims to determine the pressure ratio produced by the Suzuki Baleno EFI engine by using different lubricants. The experimental method was used in this study by testing two lubricants (i.e. SAE 30 and SAE 40) and comparing the ratio of the pressure produced. The results showed that the ratio of the pressure produced between lubricants of SAE 30 : SAE 40 was 1: 1.5 at 800 rpm; 1: 1 at 1500 rpm; 1: 1.06 at 2000 rpm and 1.1: 1 at 2500 rpm. T-test was used to compare the significance of the use of SAE 30 and SAE 40 as lubricants on the pressure ratio through operating the EFI Suzuki Engine. It can be concluded that the SAE 40 lubricant will produce a greater pressure compared to SAE 30 at a low speed of 850 rpm. However, the rotation of 1500 rpm and 2000 rpm will produce the same pressure, as well as at 2500 rpm with using SAE 30 and SAE 40.