bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Problem of Synchronization of Virtual and Real Movements for Virtual Reality Systems
Authors: Chertopolokhov V A
Published: November 2021

An immersive experience in modern virtual reality systems requires adjusting of various parameters. This report focuses on the problem of virtual representation of real movements of objects in space. Separately, a special class of problems is highlighted: synchronization of visual and dynamic imitation for virtual reality systems and motion platforms. Modern mass-produced virtual reality headsets do not allow effective tracking of human movements on a moving base using standard software. The element base and algorithms necessary for the successful solution of this problem are presented.
Methods of teaching physics in the conditions of online interaction
Authors: Dankin D G
Published: November 2021

The article discusses the problems of education caused by the pandemic and the possibilities of electronic educational tools. The challenges of the period that 2020 brought sharply accelerated the development of electronic educational tools, at the same time, revealed the limitations of student control tools. The author of the article worked in the educational system of a school, university and pre-university training in the spring of 2020. This article discusses three options for implementing online classes. All three of these systems have switched to the electronic form of online classes, although this situation was not initially foreseen. The problems that one had to face in the work and the successful moments of the studying in the information educational environment are described. Prospects for the development of online learning are outlined.
The use of electronic technologies in medicine
Authors: Damulin I V , Strutzenko A A
Published: November 2021

The active devoted of the information technologies in medicine significantly facilitates the work of a doctor, but also creates a number of problems. One of them is related to the use in practice of documents on electronic media, including electronic medical records, and is related to personal information about the patient, which is strictly confidential and which can be stolen by unauthorized access using the capabilities of the Internet and especially social networks. Another problem associated with the use of electronic media is the possibility of uncontrolled introduction of false or erroneous information about the patient. One way to avoid mistakes associated with transferring information about one patient to an electronic document of another is to strictly identify each block of information. The importance of modern distance and multimedia teaching methods in the teaching process is emphasized. It is concluded that the future development of medical education in general, and the teaching of nervous diseases in particular, is associated with the combination of traditional methods with the capabilities of modern technical methods. Despite all the objective difficulties, it is vital to correct the situation. And here the professional experience of the doctor plays an important role. Given the fact that the use of these technologies is expanding more and more every year, the understanding of the complexities associated, with the ethical component of these methods, must be taken into account now.
Numerical simulation of the interaction of the disturbed boundary layer with an incident shock
Authors: Khotyanovsky D V , Kudryavtsev A N , Kutepova A I
Published: November 2021

Interaction of the disturbed supersonic boundary layer with an incident oblique shock wave is studied numerically with eddy-resolving numerical simulations. Eigenmodes of the linear stability theory are used to generate the inflow boundary layer disturbances. The evolution of unstable boundary-layer disturbances, effects of the incident shock on the disturbances, effects of the disturbances on the boundary layer separation, flow dynamics in the separation zone, and laminar-turbulent transition are studied.
Investigating heat transfer in an upward flow of liquid metal in the mercury facility with a loop of natural circulation
Authors: Luchinkin N A , Razuvanov N G , Sardov P A , Polyanskaya O N
Published: November 2021

Research of heat transfer is performed in an upward flow of liquid metal in a vertical channel of rectangular cross-section under the condition of one-sided heating and in a vertical pipe in a mercury circuit with a natural circulation loop. Natural circulation loop enables measurements in mixed turbulent convection modes, which are inaccessible on a contour with a forced convection, that is, in the region of small Reynolds (Peclet) numbers of characteristics. Using a two-coordinate probe with a microthermocouple correlation sensor, profiles of averaged velocity and temperature and distribution of a wall temperature are obtained, and heat transfer coefficients are determined. Criterion dependences of Nusselt number on Peclet and Richardson are built. Experimental data on heat transfer are compared with similar data obtained earlier in a loop with a forced flow of mercury.
Numerical study of gas dynamics and heat transfer in matrix channels at various rib angles
Authors: Barsukov A V , Terekhov V V , Terekhov V I
Published: November 2021

The results of numerical simulation of the separation flow in matrix channels by the RANS method are presented. The simulation is performed at the Reynolds number Re = 12600, determined by the mass-average velocity and the height of the channel. The distribution of the local Nusselt number is obtained for various Reynolds numbers in the range of 5÷15⋅103 and several rib angles. It is shown that the temperature distribution on the surface is highly nonuniform; in particular, the maximum heat transfer value is observed near the upper edge facets, in the vicinity of which the greatest velocity gradient is observed.
Investigating the effect of submerged impingement jet on heat transfer in water-alcohol mixtures
Authors: Kanin P K , Gubanova T A , Zabirov A R , Yagov V V
Published: November 2021

This paper presents new results of experiments on spherical sample cooling with submerged impingement jet in subcooled water-alcohol mixtures. The influence of the ethanol concentration on the occurrence of intensive boiling regime is detected. Experiments are carried out on a stainless-steel sample in a water-ethanol mixture, in a wide range of concentrations and temperatures. The result includes an increase of the heat transfer intensity at exposure of the submerged impingement jet. The intensive boiling regime is detected with a higher ethanol content compared to experiments in a calm liquid.
Experimental study of the local structure of a bubble flow in a flat channel with sudden expansion
Authors: Chinak A V , Evdokimenko I A , Kulikov D V , Lobanov P D
Published: November 2021

The hydrodynamic structure of the flow in a flat channel with sudden expansion was studied at constant flow rates of liquid and gas in the vertical flow at Re = 6600 and gas content β = 0.03. The measurements were carried out using the PLIF method; and with this view, fluorescent particles for PIV studies and the dye Rhodamine G were added to distilled water. An optical threshold filter was installed on the lens of the video camera. When processing images to obtain data on the local gas content, only bubbles falling into the plane of the laser beam were considered (the boundary glows, casting a shadow).
Regularities of vortex motion in gas-vortex bioreactor
Authors: Sharifullin B R , Naumov I V , Tsoy V A , Skripkin S G
Published: November 2021

Regularities of the vortex motion in an industrial glass bioreactor with a volume of 12 liters with a reactor vessel diameter D = 190 mm and with a filling of 50% was studied. A 65% water solution of glycerin was used as a model culture medium (density ρ
g
= 1150 kg/m3 and kinematic viscosity Vg
= 15 mm2/s). Methods of particle image velocimetry and adaptive track visualization were used to observe the vortex pattern. The regularities of the vortex motion of the cultural medium were determined. It was found that, similar to the case of two rotating immiscible liquids, a strongly swirling jet was formed near the axis, and the entire flow took on the structure of a miniature gas-liquid tornado. The aerating gas interacted with the liquid only through the free surface, without mixing with it. As a result, the intensification of interphase mass transfer was provided due to the high speed of motion of the aerating gas.
Thermal expansion of solid solutions of the Pb(Zr,Ti)O3 system near lead zirconate
Authors: Andryushin K P , Andryushina I N , Shilkina L A , Reznichenko L A
Published: November 2021

Ferroelectric ceramic materials based on the Pb(Zr,Ti)O3 (PZT) system were obtained by two-stage solid-phase synthesis followed by sintering using conventional ceramic technology. On the basis of the studies correlations between the thermal expansion and structural parameters of the investigated solid solutions were established. It was concluded that the obtained data are recommended to be used in the development of devices based on solid solutions with the participation of the PZT system.
Numerical simulation of the shock-wave structure of a reacting hydrogen-air mixture in a model channel
Authors: Kukshinov N V , Mamyshev D L
Published: November 2021

The paper deals with the results of numerical simulation of hydrogen-air combustion in a supersonic flow of a model channel of a known configuration, investigated in the “HyShot” project. The simulation is carried out by solving the Favre-averaged system of Navier-Stokes equations, supplemented by a turbulence and combustion model and a chemical-kinetic mechanism. The influence of different throat heights on the performance of the model due to combustion efficiency and total pressure loss coefficients is investigated.
Results of numerical simulation on a thick teardrop airfoil at low Reynolds numbers
Authors: Akimov M A , Polivanov P A
Published: November 2021

A symmetrical thick teardrop airfoil was investigated in this work. A numerical simulation was performed with a laminar flow, using the Implicit Large Eddy Simulation method. The fields of flow parameters in the vicinity of the airfoil were obtained for Reynolds numbers 3.5e+4 and 6.9 e+4.
Thermodynamic properties of propane and methane hydrates doped with sodium hydroxide
Authors: Gets K V , Zhdanov R K , Bozhko Yu Yu , Belosludov V R
Published: November 2021

Pure and sodium hydroxide doped with single-component hydrates of methane and propane are studied using molecular and lattice dynamics methods. Vibration density of states and the dependence of Helmholtz free energy on temperature and cell volume are calculated. Dynamic stability of empty and filled by gas sI and sII structures doped with 1 or 2 NaOH molecule is shown in the wide range of temperature values. Comparison of free energy values allows calculating the thermal expansion coefficient and demonstrating the possibility of self-preservation effect in NaOH-doped methane and propane hydrates with ~1.8 and ~1.4 mol% of sodium hydroxide, respectively.
Assessing the effect of proppant compressibility on the conductivity of heterogeneously propped hydraulic fracture
Authors: Skopintsev A M
Published: November 2021

Hydraulic fracturing is a technology that is widely used in the development of oil and gas formations. Given that the fracture closure has a strong impact on production, quantifying the resulting fracture conductivity is critical for optimizing treatment design. The goal of this paper is to better understand the influence of the closing stress on the fracture conductivity when the proppant distribution is heterogeneous. In addition to the spatial proppant distribution, the conductivity of the propped fracture is affected by proppant deformation and embedment. Numerical results indicate that compressibility of proppant can significantly change the residual fracture aperture and, consequently, production performance in oil and gas reservoirs
Simulation of a laminar-turbulent flow in three-dimensional aerodynamic configurations
Authors: Poplavskaya T V , Boiko A V , Demyanko K V , Kirilovskiy S V , Nechepurenko Y M
Published: November 2021

The goal of the paper is to determine the position of the laminar-turbulent transition in the boundary layer of a prolate spheroid using the eN-method with the calibration of threshold N-factors. It is demonstrated that the predicted and experimental data on the laminarturbulent transition are in good agreement.
Quality estimation of the nozzle spray by measuring the brightness of the reflected light
Authors: Batalov V G , Stepanov R A , Vasilev A U
Published: November 2021

This paper presents the results of the laboratory and numerical experiments performed to measure the sizes of transparent liquid droplets sprayed in air. The results of the laboratory experiments were mainly obtained using the Glare Point Technique (GPT) which gave information about the droplet size and the brightness of the light reflected by drops. The relationship between the brightness of the light reflected from the surface of droplets and their sizes was analyzed. Theoretically, the brightness of light scattered by a single spherical drop is proportional to the drop surface area and, accordingly, to the square of the drop diameter. It has been observed experimentally and verified numerically that the theoretical dependence obtained is relevant only for the brightest droplets because of nonuniform illumination. The results of the numerical experiments with a random sample of drops indicated the dependence of the total brightness of reflected light on the effective droplet size. It is shown that, for a fixed total volume, the total brightness of light reflected by drops is proportional to the droplet Sauter mean diameter.
Software package for testing three-dimensional shape measurement methods using structured lighting
Authors: Dvoynishnikov S V , Zuev V O , Kabardin I K , Kulikov D V , Rahmanov V V
Published: November 2021

This work aims at creating a universal software package for the development and testing of triangulation methods using structured lighting for measuring the three-dimensional geometry of objects in difficult ambient lighting conditions. As a result, a software package meeting the stated requirements is created. Lighting is based on the Fong model. A method for preloading objects is implemented to optimize the operation of the software package. An accelerated method for creating shadow maps is proposed and implemented. The developed software package is shown to successfully perform all required functions.
Problems of an experimental study of a reverse flow in the turbulent channel flow
Authors: Zaripov D I
Published: November 2021

The problems of experimental study of the near-wall reverse flow (NWRF) phenomenon observed in a turbulent channel flow are discussed. Until now, the problem of detecting the NWRF events has been associated with the lack of spatial resolution of measurement methods. The present study, using the example of high-speed PIV measurements, shows that problems associated with the influence of the measurement error arise even when a high spatial resolution is achieved.
Estimating the uncertainty of measurements of thermal conductivity of thin films of thermoelectrics with the 3-omega method
Authors: Makarova E S , Novotelnova A V
Published: November 2021

Using the method of computer simulation, the uncertainty of measurements of the thermal conductivity of silicon, which is often used as substrates, and also thin films based on bismuth, is estimated. The influence of the application of an additional dielectric layer between the thermoelectric film and the resistive heater on the measurement results is shown.
Thermal expansion of nickel-chromium ChS88U alloy at high temperatures
Authors: Kozlovskii Yu M , Stankus S V
Published: November 2021

The experimental results of the study of thermal expansion of nickel-chrome alloy in the temperature range of 293.15–1400 K are presented. The phase transformation of the first kind in the alloy is observed. The estimated error of the obtained data is 3%. Approximation equations and a table of reference values for the temperature dependence of the studied properties are obtained.
Equation of state for rhodium at high pressures
Authors: Khishchenko K V
Published: November 2021

An equation of state has been developed for rhodium in a wide range of changes in the specific volume and internal energy. The results of calculations of the thermodynamic characteristics of this metal are presented in comparison with the available experimental data at high pressures. This equation of state can be used in the numerical simulation of hydrodynamic processes under intense impulse influences on matter.
The study of the effect of forced air supply on the combustion of liquid fuel dispersed by superheated steam
Authors: Mukhina M A , Kopyev E P , Anufriev I S
Published: November 2021

In the present work, the effect of forced air supply on the combustion process of liquid hydrocarbons was studied using diesel fuel as an example. The content of intermediate components of the flame and the temperature distribution along the flame symmetry axis were studied using an atmospheric burner with liquid fuel atomizing by a steam jet. The gas composition of equilibrium combustion products and the heat release were investigated. The influence of the excess air ratio in the combustion chamber of the burner device on the thermal and environmental characteristics was shown.
Studies various factors effecting the synthesis of submicron silicon dioxide particles by leaching from waste dumps of the Balaklavskoe deposit
Authors: Turyanskiy V A , Baranov G A , Chayka T V , Gavrish V M
Published: November 2021

The paper presents the results of studies of the main parameters of synthesis of silicon dioxide powder from Balaklava deposit sludge with silicon dioxide content of 24%. During the study caustic soda solution is used as a leaching agent and sulfuric acid was used as a precipitant. At the leaching stage the concentration of leaching agent, the ratio of liquid phase to solid phase, the optimum temperature of leaching as well as the mode of pulp agitation are investigated. At the precipitation stage, the following parameters are considered: concentration of precipitating agent and temperature of the precipitation process. As a result of using the optimal parameters the high efficiency of obtaining silica powder of 98.56% is achieved. Average particle size is 200-800 nm, and agglomerate size is more than 800 nm.
Wafer Direct Technology for Mini LED Flip Attachment
Authors: Hiraki Kazuo
Published: November 2021

We would like to introduce the mechanism structure of our wafer direct die attachment technology for mini LED. Wafer direct technology is structured from two parts of that one is adhesive one shot dipping and other is pinhole free chip shooting. 1st, we developed “One shot wafer dipping” which can transfer the adhesive to around 30,000 chips of mini LED on a wafer at once. Second section is to take about die mounting. Common die bonder use an ejector pin to pick up mini LED chip. Ejector pin makes a pinhole on wafer and lead air into between wafer and mini LED chip. This air is effective to remove mini LED chip from wafer by the pick up nozzle. Ejector pin of die bonder leaves a broken piece of wafer on chip. We developed wafer direct chip shooting technology. Wafer direct chip shooter also use an ejector pin for shooting down mini LED chip. But wafer direct does not make any pinhole on wafer that means no broken piece of wafer exists. Our wafer direct technology maximize productivity of mini LED die bonding and minimize faulty ratio of mini LED die bonding.
Influence of Different Surface Passivation on Photoelectric Properties PbS QDs
Authors: Yang Yingxiang , Pu Hongbin , Bei Xu , Chen Chunlan , Wang Min , Hu Xiamiao
Published: November 2021

The photoelectric characteristic of ITO/PbS quantum dots (QDs)/Al structure based single and hybrid iodine ions(I−) passivated PbS QDs have been investigated. The ITO/PbS QDs/Al structure with hybrid I− passivation have demonstrated a high light dark ratio of 565.5 at -2V. It is the result of removing more organic ligands on the surface of PbS QDs and introducing larger amount of I−. This work demonstrates that the hybrid I− passivated process has great potential in the performance improvement of PbS QDs based photovoltaic device.
Research on CarMaker and Cloud Computing Platform Co-Simulation Based on APO
Authors: Ren Nver , Jiang Rong , Zhang Dongze
Published: November 2021

An cloud computing platform based on B/S architecture and docker container technology for autonomous driving simulation has been established in this paper. The map editor module of the cloud platform lets users design 3D scenes for simulating and testing automated driving systems. When the customized roadway scene for simulation created, it would be saved as OpenDrive format both for the server of cloud platform and CarMaker’s TestRun which all parameters of the virtual environment (vehicle, road, tires, etc.) are sufficiently defined. Then, based on the application online (APO) communication protocol of CarMaker, the local APO agent service was created. When the 27 parameters of vehicle dynamics received from CarMaker server, they were sent to the cloud platform in real time through UPD protocol. The process of data communication is completed by APO agent. Through the work above, a co-simulation between cloud platform and CarMaker could be successfully established for autonomous driving with seventeen-degree-of-freedom. Through the co-simulation experiment, it is found that the real-time data sampling frequency of the co-simulation is 70Hz, which completes the synchronous simulation of carmaker and cloud platform.
Topology Optimization and Design for Additive Manufactured Supporting Structure of Vehicle Rudder
Authors: Chen Jingyi , Xin Kehao , Gu Xiaolong , Ji Hongjuan
Published: November 2021

The object investigated in this work is a design method for the supporting structure of vehicle rudders, which are the crucial components in flight control system. As a practical application of topology optimization for additive manufacture, the design process was presented in this article. To obtain the optimal material distribution, topology optimization based on SIMP method was applied, with compliance minimization as the optimization objective. A numerical optimization model was built and calculated in Inspire, and the result in an equivalent load scheme of 30 percent point load and 70 percent uniform pressure was adopted to be the initial geometry for the subsequent design. Concentrating on realizing the optimized geometry, this design took a series of technical constrains for additive manufacture and mass requirements into consideration. Notably, the FEM simulation for the supporting structure is necessary, which consist of stress analysis and mode analysis. And the technical feasibility was verified in its practical manufacturing process. Finally, by the experiment about dynamic characteristic, it is verified that the lightweight rudder designed in this work can satisfy all the requirements for flight control.
Fracturing Parameters Optimizing Simulation of Horizontal Well In WeiYuan Shale Gasfield
Authors: Che Mingguang , Wang Meng , Zeng Bo , Song Yi , Jiang Wei , Zhang Xiaofeng , Dong Kai
Published: November 2021

Multistage fracturing and multi-clusters with long lateral fracturing were applied during developing the WeiYuan shale gas field, and the fracturing parameters were variable obviously for the fracturing lateral, perforating clusters, pumping rate, fracturing fluid volume and proppant quality. In this paper, the 3D geological model of a WeiYuan shale gas pad was used to simulate and optimize the fracturing parameters of the shale gas horizontal wells. The simulating results show that there is a reasonable matching relationship between different fracturing lateral length and the perforating clusters, and there is an optimal fluid volume and proppant quality. As the length of the fracturing lateral and the number of clusters increase, the spacing of horizontal wells need to be reduced reasonably. With the purpose of fracturing parameters optimization for WeiYuan shale gas horizontal wells, it is recommended to increase the number of perforation clusters, increase the treating rate, and use the reasonable fluid volume and proppant quality for different fracturing lateral. The research results of this paper have guiding significance for the optimization and treatment of fracturing shale gas horizontal well.
Modelling igneous rock mechanics parameter based on logging data in Shunbei oil field
Authors: Li Wenxia , Song Weiqiang , Liu Jingtao , Chen Xiuping , Mu Huidong
Published: November 2021

In order to improve the rate of penetration (ROP) in Permian igneous rock strata, the rock mechanics is modeled based on the continuous logging data (acoustic, density, caliper, resistivity and gamma logging) and confirmatory indoor experiments. The model considers the influence of well collapse and expansion on logging data in igneous rock formation to improve the calculation accuracy. Based on this model, the continuous profile of Permian compressive strength, tensile strength, mud content, internal friction angle are calculated, and then the differences of Permian strata in the north, middle and south of the oilfield are further compared and analyzed. The results can provide support for the optimization of efficient rock breaking and reservoir fracturing technology.
Design of solar light tracking system Research on energy autonomy system design of outdoor patrol car based on solar energy
Authors: Wang Wen-Lan , Bai Xiong-Huai
Published: November 2021

The Inner Mongolia has abundant solar energy and electricity resources. Because of the long distance between cities, transmission lines are too long, making it difficult to check lines. In order to solve the problems existing in the inspection work, this paper studies a kind of outdoor inspection vehicle using solar energy, the energy system of the inspection vehicle can independently complete the charge and discharge, so as to realize the inspection task. This paper focuses on the energy autonomy of the on-site inspection vehicle for solar energy. According to the design requirements of the inspection vehicle, appropriate parts are selected to build an energy autonomy inspection system for the inspection vehicle. Then the solar tracking algorithm and maximum power tracking control algorithm are used to improve the conversion rate of solar panels and achieve fast charging. Finally, the hardware and software of the solar controller are designed, and the corresponding functions are debugged.
Application of Micro-resistivity Scanning Imaging Logging Data in Reservoir Thickness Division
Authors: Wang Xinnan
Published: November 2021

Reservoir parameter interpretation is one of the main contents of reservoir description, which affects the whole process of oilfield development. According to the characteristics of micro-resistivity scanning imaging logging, which can directly reflect the changes of lithology and physical properties of reservoirs, this paper compares the thickness and interbed division of reservoirs with conventional logging data, this paper finds out the shortcomings of the conventional logging data in the interpretation of thickness and the division of interlayers, and combines the core analysis data to examine the differences in the correlation on the coring wells, and obtains good results, it has laid the foundation for the establishment of new interpretation procedure.
Research Progress on Calculation and Control of Unaccounted for Gas of Natural Gas Pipeline Network
Authors: Chen Huiyu , Li Shanshan , Zuo Lili , Li Wanjun
Published: November 2021

At present, volume measurement is still used in transfer measurement of natural gas in China, so the calculation and management of Unaccounted for Gas are based on volume measurement. With the change of natural gas measurement method from volume measurement to energy measurement, the calculation and management of Unaccounted for Gas based on energy measurement will be paid more and more attention. This paper investigates the calculation methods and management measures of Unaccounted for Gas based on volume measurement in China and Unaccounted for Gas based on energy measurement in other countries, and compares the research progress. The results show that: the general principles of Unaccounted for Gas calculation in China and other countries are basically the same, but the calculation formulas are not completely the same. All countries consider the input gas, output gas, line pack variation and self-consumption gas. On this basis, Italy considers the known leakage, and Britain considers the known leakage and the daily calorific value shrinkage caused by its settlement rules. In order to reduce Unaccounted for Gas, the UK regularly verifies meter, carries out the research on Unaccounted for Gas baseline, and actively participates in the global Unaccounted for Gas benchmarking. Australia replaces the old main line and reduces the operation pressure of pipeline, which significantly reduces Unaccounted for Gas. The calculation methods and control measures of Unaccounted for Gas based on energy measurement in Italy, Britain and Australia can be used for reference in China.
Study on Renewable Energy Accommodation Capacity Assessment Method Based on Time Series Production Simulation
Authors: Su Yinsheng , Ma Qian , Zhang Qiang , Yuan Quan , Huang Xinlei
Published: November 2021

In order to solve the problem of low accommodation rate of renewable energy in a single region, considering the output characteristics of wind power and photovoltaic, grid constraints and cross regional power exchange, an optimization model of renewable energy accommodation capacity in a cross regional power grid year is established. This paper analyzes the factors restricting the accommodation capacity of renewable energy, and determines the access scale of renewable energy units according to the characteristics of different power grid scale, load and power supply structure. And then taking the annual maximum accommodation capacity of renewable energy as the goal, the time series production simulation model is established, considering the constraints such as regional load balancing, power transmission and output of the network cable, unit output, unit optimization power ramp rate and renewable energy output. To improve the renewable energy accommodation capacity, the three factors of power system interconnection level, power regulation performance and load characteristics can be considered.
Transient Response Analysis of Multi-layer Sloshing Fluid in LNG Tank
Authors: Song Liye , Deng Jiajia , Lu Jinshu , Wang Bin , Xue Dawen
Published: November 2021

The stratified LNG is the potential cause of rollover, so the analysis of the interface behavior is very important. In this work, a three-layer dynamic simulation model of BOG, LNG, and liquid nitrogen of sloshing stratified LNG in a tank was built. The transient behaviors of the layers were simulated, and the effects of factors such as the period of sloshing (T = 0.2, 0.4, 0.6, 0.8 and 1.0 s) and the amplitude of sloshing (A=0.01~0.06 rad) were analyzed. It was found that instability of the interface was aggravated over time. There was a specific period of sloshing in which the layers of fluid were relatively stable, away from this period the fluid layer became less stable. The influence of sloshing amplitude on the behavior of the interface presented a wave characteristic. The simulation results of the coupling with different sloshing periods and sloshing amplitude showed that the interface behavior of stratified sloshing was the most severe when the sloshing period was 0.2 s and the sloshing amplitude was 0.05 rad.
Study on turbulent flow in <1-2> wave wall tube heat exchanger
Authors: Zhang Liang , Zhang Anlong
Published: November 2021

The traditional straight wall tube heat exchanger has low heat exchange efficiency, in order to solve this problem, the turbulent flow in wave wall tube heat exchanger was studied by numerical simulation. It is found that the unique corrugated structure of the heat exchange tube in the wave wall tube heat exchanger can improve the flow state of the fluid in the heat exchanger. The average pressure drop of heat exchanger gradually increases with the increase of Reynolds number Re. Under the same conditions, the average pressure drop of wave wall tube heat exchanger is lower than that of straight wall tube heat exchanger. The improvement of heat exchange performance of heat exchanger can not be realized only by increasing the inlet flow of heat exchanger. The wave wall tube heat exchanger can strengthen the heat exchange of the fluid in the heat exchanger.
Threshold pressure experiment of liquid flows through nanochannels and tight cores
Authors: Xiao Jiajia , Song Fuquan , Jiang Jingjing , Liu Guanghao , Wang Lingyun
Published: November 2021

Compared with low-permeability oil reservoirs, tight oil reservoirs have more nanopores, complex pore structure, and more obvious nonlinear seepage characteristics. Under the macro-scale channel flow, the influence of micro-forces is often ignored, but micro-forces of the micro-nano-scale have become the main factors affecting the flow. The micro-nano-scale flow is different from the macro-scale flow, and the flow requires the force between the fluid and the micro-nano tubes. The article conducts the threshold pressure experiment of nanochannels and cores, and results show that exists a pressure threshold under liquid flows through nanochannels and cores. The influence of the threshold pressure gradient in the micro-nanochannels is analyzed, and it is found that the nature of the fluid and the diameter of the pores affect the threshold pressure of micro the tube; core experiments prove the threshold pressure gradient exists in the core. The main factors affecting the threshold pressure gradient of the core are the permeability of the core and the nature of the experimental fluid.
Physicochemical characterization of the performance of acidified modified eggshell cyclic adsorption of CO2
Authors: Cheng Hanhan , Gong Dehong , Zhao Ting , Wang Tingyi , Jiang Song
Published: November 2021

The CO2 calcium based adsorbent was prepared by using citric acid monohydrate, L(+)-tartaric acid, glacial acetic acid and L(-)-malic acid modified eggshell. The cyclic calcination/carbonation reaction of the adsorbent before and after modification was carried out by thermogravimetric analyzer to investigate the attenuation characteristics of the cyclic CO2 absorption performance of the calcium-based adsorbent after modification. XRD, N2 adsorption analysis and other methods were used for physical and chemical characterization. The phase composition, morphology, specific surface area and porosity of the acidified calcium based adsorbent were investigated. The results showed that: during 20 cycles of calcination/carbonation after 900°C pre-calcination, the maximum carbonation conversion of CIES900 modified with citric acid is significantly higher than that of the previous adsorbent, and its maximum carbonation conversion is 90.7%. The L(-)-malic acid modified adsorbent MAES900 significantly enhanced the carbonation cycle stability of the adsorbent before modification, and the cycle stability reached 92.9%.
Environmentally Friendly Cp*Co(III)-catalyzed C-H Bond Hydroarylation of Alkynes
Authors: Zhao JiaKai , Mou Qi , Niu RuiHan , Zhao RuYuan , Sun Bo
Published: November 2021

A facile synthetic method of Alkenylarene derivatives via cobalt(III)-catalyzed C-H hydroarylation with terminal alkynes has been presented. This helpful protocol provides a way to use terminal alkynes to couple with aryl groups through 1, 2-insertion, with high yield and good selectivity to obtain the corresponding hydroarylation products.
Comparative analysis of machine learning algorithms in water extraction
Authors: Li Aimin , Fan Meng , Qin Guangduo
Published: November 2021

There are many traditional methods available for water body extraction based on remote sensing images, such as normalised difference water index (NDWI), modified NDWI (MNDWI), and the multi-band spectrum method, but the accuracy of these methods is limited. In recent years, machine learning algorithms have developed rapidly and been applied widely. Using Landsat-8 images, models such as decision tree, logistic regression, a random forest, neural network, support vector method (SVM), and Xgboost were adopted in the present research within machine learning algorithms. Based on this, through cross validation and a grid search method, parameters were determined for each model.Moreover, the merits and demerits of several models in water body extraction were discussed and a comparative analysis was performed with three methods for determining thresholds in the traditional NDWI. The results show that the neural network has excellent performances and is a stable model, followed by the SVM and the logistic regression algorithm. Furthermore, the ensemble algorithms including the random forest and Xgboost were affected by sample distribution and the model of the decision tree returned the poorest performance.
Microstructural evolution along the build height of laser melting deposited TA15 alloy
Authors: Rizwan Muhammad , Ullah Rafi
Published: November 2021

This study emphasizes the TA15 alloy microstructural distribution fabricated by the laser melting deposition (LMD) technique. The motivation of the study is to analyze the microstructural features, such as grain or laths thickness, phase fraction, and porosity occurrence in the different regions along the build height, due to the complex thermal-solidification history during the laser melting deposition. During laser deposition of titanium alloy, the laser beam forms a melt pool, where the near-α and α+β alloys transform into a single β-phase, followed by rapid solidification. This process is repeated when a successive layer is deposited, where the previously deposited layers are re-melted. These thermal cycles can affect the parent microstructure in the previously deposited layers. It was identified from the results that the width of α-laths was larger in the regions near the top of the build component. In comparison, the bottom region near to substrate contained fine laths due to a steep thermal gradient and repeated thermal effect. The volume fraction of β-phase was higher in the bottom region, which could be regarded as the transformed β matrix due to the successive thermal effect in the α+β field. The results also showed shallow porosity existence in the top and near to top regions. According to the morphology and size, the formation of these pores can be attributed to the gas entrapment during the deposition process.
Experimental Study on Thermal Performance of Pre-formed Thin Heating Floor Filled with Shaped PCM
Authors: Yan Quanying , Ma Chao , Wang Wei
Published: November 2021

A shape-stabilized phase change material (PCM) with high-density polyethylene was prepared as the supporting material to be added to a pre-fabricated light and dry-type heating floor. A system for underfloor heating experiments was set up in the laboratory to test the effects of average supply and return water temperatures and different temperature differences on the thermal performance of two floor heating systems under 10 different operating conditions, respectively. The results show that the surface heat-flux density of a phase change floor (PCF) is higher than that of an ordinary one at the stable stage. The proportion of heat transfer to the heating room is about 13% higher in the phase change system compared to the normal system, and the heat loss is reduced by more than 10%. At the cooling stage, the surface temperature of PCF decreases slowly, compared to the rapid decrease of the ordinary one.
Establishment and Analysis of Simulation Model for Single-pass 20 Steel Spinning
Authors: Yang Yu , Yang Jiao
Published: November 2021

With the continuous advancement of computer technology, finite element simulation has been gradually applied to the analysis of plastic deformation of metals. If a strong spinning simulation model of 20 steel cylindrical parts can be established to effectively simulate the stress, strain and surface quality of the metal deformation process, it can provide a scientific basis for the setting of spinning process parameters, thus reducing the number of spinning process experiments to determine spinning process parameters.
Constructing hierarchically porous MnO/C composite to induce diffusion kinetics for high-performance lithium-ion batteries
Authors: Zeng Dong , Qi Kai , Qiu Yubing
Published: November 2021

Hybridization with transition metal oxide is broadly realized as an attractive way to smash the capacity limitation of carbon-base materials upon lithium storage. However, the influence of metal ions on the fast reaction kinetics of the electrode is still a confusing topic. Herein, a common molten salt method is displayed to fabricate hierarchically porous MnO/carbon composites. The addition of LiCl and KCl induces the fluid reaction substance by forming molten salt at a high-temperatures to beneficially achieve the activation and breaking of the carbon particles. The abundant porous and homogeneou carbon skeletons validly raise the ion/electron diffusion and transferability to prevent MnO particles from agglomerating, thereby inducing the diffusion kinetic. Moreover, the hierarchical porous MnO/carbon composite offers a highly invertible capacity of 851 mAh g-1 at 0.1 A g-1 and outstanding cyclic performance. This work has opened up a path for metal oxidation/carbon composite materials in electrochemical energy storage.
Study on water erosion and preventive measures of last stage blade of steam turbine
Authors: Wang Zhengxian , Liu Tong , Luo Renda
Published: November 2021

In the background of carbon peak and carbon neutralization, most thermal power plants are more involved in peak regulation and even in-depth peak regulation in order to absorb new energy such as wind power and Solar power. When the turbine is running under low load, the exhaust pressure decreases, which leads to the increase of exhaust humidity. More and more turbine blades have water erosion. The erosion of the last stage blades will worsen the dynamic performance of the turbine, increase the risk of the last stage blade fracture, and threaten the safe operation of the turbine. This paper studies the mechanism of the last stage blade erosion of steam turbine, and analyzes the main factors which influence the erosion with examples. Combined with the mechanism of water erosion, the relevant preventive measures are made for reference of power supply plant.
Effect of heat treatment on the microstructure and hardness of Al0.3CoCrFeNi high entropy alloy
Authors: Zhai Hailin , Zhang Siyi , Yang Dong , Wang Chenxue , Jiang Jishen , Ma Xianfeng
Published: November 2021

In this study, the cold-rolled Al0.3CoCrFeNi high entropy alloys were heat treated at 900°C for 30min and 1050°C for 20min, respectively, to investigate the effect of heat treatment on the microstructure of the alloy. The results showed that grain refinement occurred in the 900°C/30min annealed sample, while remarkable equiaxial grains and twins appeared in the 1050°C/20min annealed sample. The hardness of samples showed a decrease trend following: as-rolled sample, 900°C/30min annealed sample, and 1050°C/20min annealed sample, which can be attributed to the dislocation elimination caused by recovery and recrystallization.
Experimental Study on the Influence of Micron SiO2 on the Kinetics of Hydrate Formation
Authors: Wu Shuai , Li Mingzhong , Zhang Chongrui , Liu Chengwei , Zhao Shuai , Wei Zhe
Published: November 2021

In order to explore the kinetic mechanism of hydrate formation in a system containing micron-sized SiO2 particles, this paper uses a high-pressure reactor device with stirring function to record changes in pressure, temperature and torque during the growth of hydrates through a data acquisition system, based on the conservation of mass in the system The principle and gas equation of state calculate the kinetic parameters of hydrate formation such as gas consumption in the reactor, hydrate formation rate and induction time, and analyze the influence of particle size and particle concentration on the kinetic characteristics of hydrate formation based on the experimental results. The experimental results show that the particle content has no obvious effect on the average growth rate of hydrate in the range of 1%-7%, but increasing the particle content can effectively reduce the hydration induction time; when the particle size is in the range of 2.5-85 μm, the larger the particle size, the shorter the hydrate induction time and the greater the hydrate growth rate.
Parameter matching and simulation analysis of power system of pure electric vehicle
Authors: Geng Jiwei , Chi Qun
Published: November 2021

The consumption of gasoline and diesel for cars is beyond imagination. Along with these problems comes environmental destruction. In order to achieve the two major indicators of power performance and economy, the most critical component of electric vehicles --- the power system is optimized and improved, and simulation is used to verify it on this basis‥ It can be concluded that the maximum vehicle speed is greater than 120km/h, the maximum gradeability exceeds 30%, the cruising range reaches 178km.
U-shaped Hanging Ring Fracture Failure Analysis in 220kV Transmission Line
Authors: Huang Rong , Zhang Gefei , Xie Yi , Feng Chao , Wang Jun
Published: November 2021

The U-shaped hanging ring was fractured in B phase fault tripping of a 220kV transmission line. They are analyzed by using macroscopic inspection of fracture, hardness test, chemical composition analysis, fittings load calculation, metallographic structure analysis and scanning electron microscopy analysis. The results show that there is a current flowing through the ground wire when the high-speed rail passes through. Poor contact between the U-shaped hanging ring and the clamp steel anchor caused heating and then high temperature wear. Long-term operation eventually led to fracture.
CFD Analysis on the Mixing Effect of Orifice Diameter in Dxygen Mixer
Authors: Zhang Xiaofeng , Ye Jihong , Ye Mao , Chen Kezhen
Published: November 2021

Rapid and uniform gas mixing is one of the core technologies of the chemical industry. A three-dimensional physical model of the oxygen mixer is established to investigate the influence of orifice diameter on mixing uniformity. And the standard k-ε turbulence model and species transport model are used to simulate the gas mixing process by using the computational fluid dynamics (CFD) commercial software Fluent. The oxygen distribution in the downstream of the mixer is analyzed qualitatively and quantitatively. It is found that the oversized and undersized orifice diameter are not desirable. It is concluded that the mixing performance of the case 2 is the b-est. In case 2, the oxygen mixing uniformity of the outlet section reaches the minimum value, which is 0.0001, which is the optimal structure.
Research on Scale Model of Typical Tension String of UHVDC Transmission Lines under Ice-Shedding Loads
Authors: Liu Peng , Si Jiajun , Zhou Lixian , Zhu Kuanjun
Published: November 2021

Tension insulator string is one of the important components of transmission lines and it needs to have enough mechanical strength to transfer the load between conductors and towers. However, due to the large size of the tension insulator strings, it is usually impossible to carry out the true type experiments. In this paper, the dimensional analysis was adopted to establish the mapping scale models of typical tension strings, namely 8N42-50100-55P at first. Then, the load scaling ratios of three typical tension insulator strings were obtained based on the results of the ice shedding calculation on an actual UHVDC transmission lines. Finally, the dynamic experiments of the scale tension insulator strings were carried out to access the feasible of technical route and to provide a technical support for the following research.