bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on fatigue of subway antenna beam
Authors: Zhou Yeming , Cai Chuandong , Jiang Yongzhi
Published: April 2020

The dynamic fatigue life theory starts very late. As an important part of the subway, the antenna beam has played a great important role on the daily life of people. To study the fatigue properties of it, the relative researches are carried out. The finite element model is set up first. Then the mode analysis is carried out. After that, the rigid-flexible coupling dynamic model is set up. Finally, the reduction analysis continued. Through the experiment and simulation, the fatigue strength and vibration transition properties are analysed. Ploymax method is carried out for modal parameter identification, then the FE model could be verified to improve the accuracy. By setting up the rigid-flexible coupling dynamic model of the subway vehicle, then the modal parameters and experimental data are compared, the model is modified and verified. Considering the impact of wheel flat scar and rail gap, the vibration transmission characteristics of bogie system are studied. In the calculation of resonance fatigue dynamic stress, FFT method is used to solve the problem. The fatigue strength of antenna beam caused by the impact of rail gap and wheel flat scar is studied, and the requirements for safe service life of antenna beam is put forward.
Measurement and Analysis of Housing Price Bubbles in 35 Large and Medium-Sized Cities: An Empirical Study Based on China’s Statistical Data from 2010 to 2018
Authors: Luo Gangqiang , Wang Qin
Published: April 2020

Based on the basic assumptions of the developers and the buyers in the housing market, this paper introduced the profit function of typical developers and the utility function of typical buyers as building the equilibrium price model of housing, and constructed the decision model between the basic value of housing, the bubbles of housing price and the degree of housing price bubbles. The absolute scale and relative scale of housing price bubbles in 35 large and medium-sized cities were calculated based on the above models. A comparative analysis was conducted on the bubble level of housing prices in 35 large and medium-sized cities in China from 2010 to 2018. Results indicated that the bubbles had an increasing trend in recent years, but there were obvious differences between cities. Housing market regulation policy should take account of the differences between cities.
Obstacles of and Countermeasures for China’s Low Carbon Community Construction
Authors: Zhu Longbin , Huang Ying , He Feng
Published: April 2020

Urban communities, as the most basic unit of the human systems on Earth, are important areas for mitigation and adaptation actions in climate change. However, with a lack of deep understanding of the status quo and composition of community carbon emissions, as well as of the issues in low-carbon actions, the measures taken are often superficial and not targeted, which makes low-carbon activities difficult to implement. This study selected different types of communities for questionnaire surveys online, and conducted field interviews and in-depth surveys afterwards in typical communities. Key data such as community energy consumption, transportation, garbage disposal, and the status of community low-carbon actions were collected, based on which the potentials of carbon reduction were analysed, the obstacles in low-carbon community construction were discussed and corresponding countermeasures were proposed.
Study on the Influence of Metro on the Housing Price Around the Line--A Case Study of Luoyang Metro Line 2
Authors: Li Pengtao , Xu Dongming
Published: April 2020

This paper takes Luoyang Metro Line 2 as an example to study the impact of the metro line on the surrounding house prices. Combining with the hedonic price model, the paper uses the linear model and the semi-logarithmic model to analyze the impact of the metro line on the surrounding house price. The results show that the surrounding house price of the metro is affected by many characteristics. The value-added benefit of the subway is the most obvious in the range of 2000 meters around the subway station, and the subway station is beneficial to the value-added of the surrounding land. At the same time, neighborhood characteristics, other location characteristics and architectural features also have a certain impact on housing prices. Finally, combined with these effects, the government and real estate developers put forward some suggestions to promote the better implementation of urban planning around the subway.
A study on Determinants That Effect Klang Valley (Malaysia) Consumer Preference in Rail Industry
Authors: Sathiaseelan Pavithran , Dava Avitra Dhivia Brhma , Mahmud Bahri
Published: April 2020

There are several factors included the services of the railways industry can influence the decision of a customer for choosing specific rail. This study aims to identify the relationship between rail fares, railway reputation, service quality, environmental concern and consumer preference towards rail transport in Klang valley. There are 384 of the respondent from Klang Valley area are participated in the questionnaire survey. SPSS version 22 is used in this study to process the collected data. The data analysis methods included in this study are descriptive analysis, correlation analysis, normality test, reliability test and multiple linear regressions. The result highlighted there is a strong relationship between all the independent variables and dependent variable. Thus, rail fares, railway reputation, service quality and environmental concern are important components for respondents in choosing a specific rail.
The evaluation of fatigue strength based on characteristic length
Authors: Hou S Q , Gao X G
Published: April 2020

Different approaches are used to evaluate fatigue behaviors according to the geometric shape and size of defects in material, though it is well known that the fatigue properties of a material are intrinsic, and should be independent of geometric shape and size. By introducing the concept of fatigue characteristic length, the failure of material occurs when equivalent stress amplitude within characteristic length reach to fatigue strength of smooth material. Using this method, fatigue behaviours of material, no matter with or without stress concentration or singularities, can be evaluated in the same way. It also can explain the “size effect” of small defects on fatigue problem. Considering the fatigue failure of material within characteristic length, the evaluation of fatigue strength for problems with stress concentration or singularity has been studied by experiment.
Risk Assessment and Management of National Defense Engineering Construction Based on HHM-RFRM
Authors: Liu Hanzeng , Chen Guiming , Lin Zhiqiang
Published: April 2020

The risk of the national defense engineering construction is generated under the influence of various factors such as personnel, mechanical equipment and environment. This paper uses Hierarchical Holographic Modeling ideas and Risk Filtering, Rating and Management theory(HHM-RFRM) research method, constructs a risk measurement model for multi-dimensional construction risk scenarios by using repeatedly iterative methods; combined with Bayes’ theorem, filters and grades multi-dimensional construction risk scenarios qualitatively and quantitatively, and finally takes a national defense engineering construction as an example to verify the practicability of the proposed model and the feasibility of the method. The evaluation method overcomes the limitations of the traditional risk assessment method with a single perspective and a single model, and better expresses the authenticity of the risk and the complexity of the system, and provides a theoretical basis for the construction risk management and decision-making of the position and practical reference.
Hazard Analysis and Quantitative Risk Assessment of Port Operation for Dangerous Goods Container
Authors: Huang Chen , Bai Yu , Lu Linlin
Published: April 2020

The occurrence of the Tianjin 8.12 accident indicates that it may lead to extremely serious production safety accidents once the risk of port operations for dangerous goods container is out of control. It could cause huge loss to personnel, property and social security, and difficulty in emergency handling of accidents. For the hazard analysis and quantitative risk assessment of port operation for dangerous goods container, this study proposes a risk assessment method that combines analytic hierarchy process (AHP) and fuzzy comprehensive evaluation (FCE). Firstly, statistically analyze relevant accident cases in China in recent years, and use the fishbone diagram method to establish a system of multi-level and multi-dimensional risk assessment. Secondly, the AHP is used to assign the weight of the evaluation indicator system. Finally, the FCE method is raised to establish the fuzzy mapping relationship. The evaluation vector calculated by the fuzzy matrix and the weight vector is used to achieve the quantitative assessment conclusion. The method is validated by an instance application of dangerous goods containers port operation of a company.
Analysis of transportation accessibility in China Shanghai Pilot Free Trade Zone Lin-Gang Special Area
Authors: Yang Guang , Zhu Lei
Published: April 2020

In the field of territory spatial planning, transportation accessibility is an important index to measure regional transportation networks. It represents how easy it is for regions to communicate with each other. As a new area of Shanghai Pilot Free Trade Zone, Lin-Gang special area will carry a huge trade market. Therefore, high demands have been put forward on both passengers and freight transport in this region. Based on GIS spatial analysis technology, this paper analyses two types of factors affecting traffic accessibility in the Lin-Gang special area. The first type is road attributes, like road length, road area, road density and road accessibility index. The second type is the spatial pattern of construction land. The results show that the transportation network in Lin-Gang special area is extremely developed, especially the southern area of Pudong International Airport, where the proportion of highway is more than half. The transportation accessibility time to Lin-Gang special area is less than two hours all over Shanghai.
Research on the correlation of dangerous driving behaviors based on naturalistic driving experiment
Authors: Liang Xingcan
Published: April 2020

In China, although road traffic safety has improved in recent years, the number of deaths caused by traffic accidents is still at a high level every year. Accidents due to drivers’ dangerous driving behavior account for a large proportion. This study designed and implemented a highway naturalistic driving experiment. The driving performance data and the observer record data obtained in the experiment were used to extract four dangerous driving behaviors: rapid acceleration, rapid deceleration, sudden steering and drowsy driving. The correlation between the three kinds of urgent behaviors and driving fatigue was analyzed qualitatively and quantitatively. Finally, the correlation model between the frequency of urgent behaviors and drowsy driving was built using Naive Bayes. The feasibility of using this method to identify drowsy driving behavior was discussed.
A Comparative Study of Two Temperature Interpolation Methods: A Case Study of the Middle East of Qilian Mountain
Authors: Shan Tong , Guangchao Cao , Zhen Chen , Fang Liu , Meiliang Zhao
Published: April 2020

Background, aim, and scope The Middle East section of Qilian Mountain was used as the study area, and the temperature interpolation method based on DEM was compared. Materials and methods The temperature average correction method and Anusplin method were used to interpolate the monthly average temperature, seasonal average temperature and annual average temperature of 13 meteorological stations in the study area, and the average absolute error and root mean square error were determined by cross-validation method. The absolute value of the coefficient and index difference evaluates the verification site interpolation results.
Results
(1) The average absolute error and root mean square error of the vertical temperature correction method ranged from 0.07 °C to 1.36 °C and 0.09 °C to 1.65 °C, and the range of Anusplin ranged from 0.16 °C to 1.3 °C and 0.24 °C. -1.49 °C; (2) Anusplin and temperature vertical correction method on the average absolute error and root mean square error index, the absolute difference between the low temperature season index is 0.09 °C and 0.00 °C, respectively, the high temperature season is 0.30 °C and 0.32 °C.
Conclusion
The temperature vertical correction method is superior to Anusplin in MAE, RMSE and R2 in July, August and September; the accuracy of temperature vertical correction in summer and autumn is higher than that of Anusplin, and Anusplin is more It is suitable for interpolation in low temperature season, and the vertical temperature correction method is more suitable for interpolation in high temperature season; the error of the two interpolation methods on the annual scale is larger, and the accuracy of temperature and temperature interpolation of Anusplin is much higher than the vertical correction method of temperature.
Recommendations
and
perspectives
Different interpolation methods are applicable to different regions, and there is no method that is absolutely suitable for the study area, and only a method that is relatively suitable for the study area. In general, the Anusplim method is more accurate than the temperature vertical correction method for the temperature of the Middle East in Qilian. The former is more suitable for the interpolation of temperature in the study area.
Study on Analysis of Risk for Rainwater Collection and Utilization for Rural Safe Drinking Water Project
Authors: Junde Wang , Yanzhao Jin , Xiaojuan Tang
Published: April 2020

Firstly, based on the actuality of rainwater collection and utilization project, systematically elaborated rural security drinking water engineering, this paper put forward to the water quantity safety guarantee system and the water quality safety guarantee system; also discusses the basic characteristic of rural security drinking water project for rainwater, the result shows that the collector surface, water storage facilities, water treatment facilities and equipment are to ensure the safety of water quantity and quality. Secondly, this paper analyze the risk source, the risk formation process and its characteristics for water quantity and quality their types, the result shows that the precipitation is the biggest risk and the engineering design standard, the construction quality, the quantity of collecting surface, water requirement and the management of the engineering implementation process are all important factors; the occurrence of water risk have the characteristics of independence, comprehensive, and the water quality risk is the result of various factors. Thirdly, this paper constructs risk evaluation index system for rainwater collection and utilization of rural safe drinking water project by analytic hierarchy process (AHP). Fourthly, based on probability theory and Bayesian theory and methods of risk assessment, water quality risk and comprehensive risk assessment model are constructed. Combining the project design, construction management and actual operation, according to the risk free, low risk, middle risk, high risk and higher risk, a total of 5 levels to set up the comprehensive risk rating standards, in order to control risks for rainwater collection and utilization, improve the reliability of water supply, and preserve water.
The cause analysis of landslide disaster
Authors: Zhang Yubin
Published: April 2020

In this paper, the mechanism of landslides, induced factors, geological characteristics and environmental characteristics of historical landslides are analyzed. The application of geographic information technology in landslide prediction and evaluation is introduced. The indexes combined with the GIS system are then extracted for the data simulation by analyzing the relationship between the internal factors and geomorphology in the landslide occurrence. On the other hand, it is pointed out that the by-product of civil engineering is the important risk source of increasing landslide disaster. This improves the reliability of the prediction and evaluation for landslide disaster and is of great significance for future observation and prevention of landslide.
Spatial prediction of landslide susceptibility based on the neighborhood rough set
Authors: Yang Xin , Liu Rui , Li Luyao , Yang Mei , Yang Yuantao
Published: April 2020

This paper discusses the feasibility of reducing the landslide inducing factors by the neighborhood rough set algorithm in data processing section, which could improve the accuracy and timeliness of landslides susceptibility prediction models effectively. 15 predisposing factors for a continuous value that has not been graded were reduced by nighborhood rough set, a granularity calculation method, based on the importance degree of each factor. Then the combination of factors before and after optimization was put into random forest (RF) and support vector machine (SVM) for modelling. ROC curve and statistical indicators show that: the average performance of the reduced factors combination is superior to that before optimization. In addition, we used the RF which has a better performs in evaluation to map the landslides susceptibility in Jiuzhaigou area, discuss the timeliness of the assessment of landslides prediction and the weight of the predisposing factors.
Analysing the Differentiation of Housing Price Influence Based on PCA Clustering-Entropy Weight Method: A Case Study in Sichuan
Authors: Liang Xuedong , Lu Qian , Lu Qian
Published: April 2020

The immobility of real estate products and the regional nature of the consumption of real estate products make the real estate industry have obvious regional characteristics. The current policy adjustments in the real estate market emphasize differentiation, that is, the regulation methods of each city are becoming more and more different, not only because of the policy of the city, but also the policy of the district. For exploring the basis of differential regulation, the article takes Sichuan Province of China as an example. Through the selection of four first-level indicators and thirteen secondary indicators, 21 cities (districts) are divided into four types of areas. Then the entropy method is used to obtain the factors that affect the housing prices in each category. Based on these, it is suggested to improve the real estate market related policies from the three aspects: promoting the construction of the housing rental market, guiding the rational expectations of buyers and correctly guiding the flow of people.
Research on Agricultural Production Efficiency of Lanzhou-Xi’ning Urban Agglomeration
Authors: Jun Luo , Xuebin Zhang
Published: April 2020

To clarify the efficiency and spatial-temporal characteristics of regional agricultural production is of great significance for adjusting the structure of agricultural production, improving the mode of agricultural production and coordinating the relationship between industries development. Based on the spatial constraints of the main function division, taking the counties providing agriculture products in Lanxi urban agglomeration as the basic research unit, using DEA model, we analyze the spatial-temporal characteristics, dynamic trends and the total factor productivity of the agricultural production efficiency from 2000 to 2015. The results showed that: 1. The overall agricultural efficiency of Lanxi urban agglomeration was very low and a few of regions were in the productive frontier, agricultural scale efficiency was greater than pure technical efficiency. 2. The spatial characteristics of the overall efficiency was “middle collapse”, while the pure technical efficiency and scale efficiency presented a gradient distribution pattern. The provincial differences showed that the overall agricultural efficiency and pure technical efficiency of Gansu Province were relatively high, while the opposite is true in Qinghai Province. 3. The overall TFP of agriculture was on the rise, and the overall efficiency improvement was shifted from the improvement of pure technical efficiency to the increase of scale efficiency. The TFP and its decomposition indicated that technological progress is the most important factor, which drives the rise of agricultural total factor productivity.
Swelling Behavior And Mechanical Properties In Filled Elastomeric Nano-Composites In Contact With Organic Solvents
Authors: Mdarhri A , Haouzi F El , Brosseau C , Aboudi I El , Bentoumi M , Azhari M EL
Published: April 2020

The effect of organic solvents on the transport process and mechanical properties in elastomeric nanocomposite materials is reported. The investigated samples are formed by a semicrystalline ethylene-co-butyl acrylate (EBA) polymer filled with hard spherical carbon black (CB) nanoparticles. The swelling behavior was studied at room temperature by immersion the dried samples in two selected solvents, i.e. toluene and xylene. The transport of the molecules of a given solvent in these filled elastomeric composites is found to follow a Fickian diffusion mechanism. Mechanically speaking, the stress-strain curves of uniaxial tensile tests pre-and post-swelling highlight a remarkably decrease of the Young’s modulus and strength of the swollen samples. This behavior can be attributed to the decrease of the load transfer density between the matrix and the CB in the presence of the solvent. The Mooney-Rivlin model is used to capture the physics of the stress-strain curves in both dry and swollen samples. The results reported in this experimental investigation can be useful for some demanding applications.
Non resonant Raman spectra of homogeneous and inhomogeneous individual dimers of Single-walled Carbon Nanotubes (SWNTs)
Authors: Boutahir M. , Abdelkader S.A. Ait , Fakrach B. , Rahmani AH. , Chadli H. , Rahmani A.
Published: April 2020

We study the effects of the coupling between single-walled carbon nanotubes (SWNTs) on the phonons in homogeneous (identical nanotubes) and inhomogeneous (different nanotubes) dimers of SWNTs. Bond polarization theory and the spectral moments method (SMM) are used to calculate the non-resonant Raman frequencies of the breathing-like modes (BLMs) and tangential-like ones (TLMs). The dependence of the phonons on different structural parameters such as diameter and chirality is investigated. We focus on the dependence of the so-called Breathing-Like Modes (BLMs) of dimers originating from the van der Waals coupling of the Radial Breathing Modes (RBMs) of each individual tube forming the dimer. On the other hand, the TLM of dimer is reported and discussed. Distinct behaviors of the TLM are evidenced. The calculated of spectra are compared with the few experimental Raman data obtained on individual dimers.
Wall thikness effects on the infrared spectra of multi-walled carbon nanotubes
Authors: Boutahir Mourad , Fakrach Brahim , Rahmani Abdelhai , Sbai Khalid , Chadli Hassan , Rahmani Abdelali
Published: April 2020

In this theoretical work, we investigate the infrared vibrational features of multi-walled carbon nanotubes (MCNTs). We calculate the polarized infrared spectra of multi-walled carbon nanotubes using the spectral moment’s method. This original approach allows us to consider MCNTs with a large number of walls. We discuss the evolution of the low, intermediate and high wavenumber regions of these spectra as a function of the inner diameter and the size of MCNTs. Both the XX and ZZ polarisations are considered. Our results provide benchmark theoretical data for understanding the experimental infrared spectra of MCNTs.
Investigation into Innovative Fabrication of Fiber Metal Laminated Pipe and Application
Authors: Zijian Lang , Meng Zhang , Xiaoxing Li
Published: April 2020

Fiber reinforced metal laminated tube (FMLT) is a kind of multi-layer super-hybrid material which is cured at a fixed pressure and temperature after alternately laying metal laminated tube and fiber composite material. The development of GLARE composite pipe hydroforming technology and performance testing is of great significance to the development of aviation industry and automotive industry in terms of lightweight and safety.
Numerical simulation of mesoscopic bubble defect and optimization of process parameters in fiber wetting process of high voltage post insulator resin
Authors: Yan B Y , Zhang Z , Yang W , Chu W , Yin L , Wang K , Dai X Y
Published: April 2020

Based on the method of fluid volume function, the two-phase flow model of mesoscopic resin and air between unit cell fiber bundles was established. The causes of mesoscopic bubble defects were discussed and the controllable process parameters were analyzed. A near-real mono-cell mesoscopic geometry model of strut insulator was constructed and meshed. The solution of the resin and air two-phase flow model was completed by adopting the finite volume method and using the Fluent software. The numerical simulation of the mesoscopic resin air two-phase flow and the air bubble defect was applied. The relationship between process parameters and air bubble defect was studied, and process parameters were optimized. Through the contrastive analysis of the capillary number, the correctness of the numerical simulation and parameter optimization was theoretically verified. Further, the effectiveness of the method in this paper was verified through the experiment.
Effect of Sputtering Conditions on Transmittance and Wear Resistance of Diamond-Like Carbon Film
Authors: Lai L F , Xu Z Y , Xu J
Published: April 2020

Diamond-like carbon (DLC) film was prepared by magnetron sputtering method on glass substrate. The microstructure, transmittance, and wear resistance of the diamond-like carbon film were investigated and analyzed. This study clearly showed the significance of sputtering power, Ar pressure and substrate temperature in controlling the transmittance and wear resistance of DLC film. The sp3 bond in the film had a greater impact on the transmittance and wear resistance of DLC film. The optimized deposition parameters obtained through experiments were: Ar pressure of 0.7 Pa, sputtering power of 100 W, and substrate temperature of 150 °C.
Research on tool path generation for integrated off-axis four-mirror group in single point diamond turning
Authors: Ning Peixing , Zhao Ji , Ji Shijun , Li Jingjin , Dai Handa
Published: April 2020

Multi-free-surface mirror integrated system is the development trend of optical system, but its ultra-precision machining is very difficult, this paper mainly studies the tool path generation problem of multi-free-surface reflector integrated system. In this paper, two tool path generation methods for the off-axis four-mirror group machining with SPDT are presented, one tool path generation method is separate machining and the other is integrated machining. Both methods are based on cylindrical spiral and generate tool path by projecting points onto surfaces. For the tool path generation method of integrated machining, the linear transition is used to realize the smooth transition of the mirror surfaces. By comparing the simulation machining of two kinds of tool path generating methods, it is found that the integrated tool path generating method is more suitable for off-axis four-mirror group machining and has higher machining efficiency.
The study on Reliability Design of Knotter Cam Gear of D-knotter
Authors: Cen Hai-Tang , Song Yu-Wei , Wei Rui-Tao , Li Ling , Qin Jian-Guo
Published: April 2020

The outer gear of knotter cam gear of D-knotter and pinion of knotter hook to achieve coordination and cooperation is important guarantee for the movement of “winding rope - biting rope”. This paper analyzes the damage mechanism of the outer gear of knotter cam gear. By application the probability theory for equal effect accuracy synthesis, the outer gear of knotter cam gear and pinion of knotter hook selected from 8 grade precision, and modification of teeth top along the normal direction of the measurement of 50.04 μm for pinion of knotter hook, can control the additional impact dynamic load less than 0.085 times of the calculated load. Two methods of traditional fatigue strength calculation and finite element analysis are used to check the strength of the incomplete outer teeth. And the results obtained by the finite element simulation described in this paper are closer to the real value. This study is of practical value in improving the reliability of the knotter cam gear and promoting the localization of D-knotter.
Stress State Measurement and Result Analysis of Car Wheels
Authors: Cheng Liu , Nianzu Ren , Qingsong Yang , Chao Chen , Cheng Tian , Zhengguo Liu
Published: April 2020

The stress state of the car wheel is one of the guiding design indicators for the wheel structure. This paper uses the combination of finite element method and bench test to study the stress state of the wheel when driving straight. Through the finite element simulation of bending fatigue and radial fatigue, the position of dangerous points during the use of the wheel is obtained. The location of the dangerous point is used as the strain measuring point, and the test bench is built. The strain gauge is used to measure the strain of these points in the straight running condition, and the test results are analyzed. The results show that when the vehicle is traveling straight, the tire will have a greater impact on the load of the wheel. The squeezing deformation between the tire and the wheel, as well as the positive and negative rotation, will have an effect on the stress state of the wheel. The maximum strain of the wheel appears on the inside of the wheel rim, the rim is in contact with the tire and along the circumference of the wheel. The strain near the center of the wheel is small. Different loads have no effect on the variation of wheel strain, but have an effect on the maximum and minimum peaks.
Static Simulation of Electric Tilting Tricycle Frame Structure Using The Finite Element Analysis
Authors: Muiz Mutqin Abdul , Jati Muhammad Kusuma , Cahyono Farras Prasrtyo , Sumarsono Danardono Agus
Published: April 2020

Electric Tilting Tricycle is a three-wheeled vehicle that has tadpole configuration driven by two sources of motion, that motion by a manual pedal and power from an electric motor. The three-wheeled vehicle has better stability and the tilting system improves ergonomics at curves. This research aims to design and analyze the strengths frame with three different materials using the Autodesk inventor software. By using the Stress Analysis feature that comes with the method of finite element analysis (FEA), we can know the result of von misses stress, displacement, strain, and safety factor. The main consideration of structural strength was seen from the distribution of static loads using three types of materials (Aluminium 6061, Steel Mild and CFRP). The minimum factor of safety resulting from the design simulation was estimated to be 1.83 using steel mild material.
Mechanical System Design and Simulation Research of a Demonstration Assembly Line
Authors: Ke MA , Yu Chen , Yi Sun
Published: April 2020

Most assembly lines use a bottom-up mechanical system design approach. In view of the problems of poor system interchangeability and low product versatility, a battery assembly line was designed based on the modular design method. The linear modules, cylinders and linear guides were used as the basic elements to build the production line modules. Different assembly requirements have improved the performance of the entire production line. The discrete-event system simulation method is used to simulate the quasi-running process of the production line, analyze the bottleneck of the production line, and improve the production efficiency of each module of the production line by changing the optimization method of the loading link and the production sequencing.
Research on water vapor measurement and removal methods for the spacecraft sealed cabin
Authors: Wu Yue , Guo Qingling , Yuan Weifeng , Xie Zheng , Wei Xi , Wang Jing
Published: April 2020

In order to develop a water vapor measurement and dewatering device suitable for ground test of spacecraft sealed cabin. A moisture measuring device suitable for the sealed cabin was designed. The existing moisture content measuring sensors were equipped with auxiliary devices to protect the electrical circuit of the sensor, and then the sensor was calibrated and analyzed. After calibration, it can meet the requirement of moisture measurement in vacuum environment. A small chamber was built to study water change rule in the pumping process. In the water removal system, the cabin was connected to the vacuum pump system through a two-way sealing flange, which can complete the water removal outside the vacuum chamber by pumping. When the pressure of the sealed cabin reached 100 Pa, high purity nitrogen gas was added to 97 kPa, then pumped in again. The results show that the water removal method can ensure that the dew point temperature of the sealed chamber is lower than 0°C during the vacuum thermal test. After protected, the dew point sensor can measure moisture at low pressure. The water removal system can effectively remove the moisture in the sealed cabin, thus ensuring the completion of the vacuum thermal test.
Design and Numerical Simulation of a High Speed Centrifugal Compressor
Authors: Yu Qingyang , Wu Peng , Deng Yelin
Published: April 2020

The issue of energy consumption has attracted worldwide attention, therefore the performance requirements of rotating machinery are getting higher and higher in modern commercial run. Active magnetic bearings have the advantages of high speed and low friction, so they are widely used in high-speed rotating machines such as high-speed centrifugal compressors. A stage of impeller and diffuser was designed. Numerical simulations of the flow field were performed using CFX. The pressure and velocity field in the model stage (impeller and diffuser) were obtained and analyzed. The results show that the model stage has uniform velocity field distribution and regular flow field, and the performance parameters can well meet the industrial requirements.
Analysis of manhole structure Safety of draft tubes in hydropower plant
Authors: Li Wenbo , Zhang Jun , Liu Lanlan , Li Xiaokai , Wang Jun , Zhou Hengyi , Xie Yi
Published: April 2020

The fault of the manhole on draft tube in a hydropower plant was investigated and analyzed. The results showed that the main reason for the cracking and leakage of the manhole on draft tube was that: the four corners of the manhole were not rounded, so fatigue cracks appeared under the effect of long-term alternating loads, which caused the leakage at the four corners of the manhole on draft tube during unit operation.
Case analysis of mechanical maintenance supply scheme based on NSGA-II algorithm
Authors: Xia Wei , Shi Quan , Wang YaDong
Published: April 2020

Based on the maintenance strategy of mechanical equipment, the mechanical maintenance supply scheme is designed and studied. Combined with a specific case, the intelligent optimization algorithm is used to solve the model, and a series of Pareto optimal scheme sets are obtained. Compared with other classical intelligent algorithms, the effectiveness and robustness of the algorithm are verified.
Numerical analysis of the effect of turbulence on particle agglomeration
Authors: Zhang Weikuo , Liu Guanqing , Zou Chongen
Published: April 2020

The turbulent agglomeration characteristics of a mechanical elements were investigated by numerical simulation using the SST k-ω model. The vorticity field, turbulent dissipation rate and pressure drop in the flow field were obtained. The results show the bluff body flow phenomenon occurs when the incoming flow passes through the spoiler element. On the back of the element, a periodic vortex similar to Karman vortex street is formed. After the airflow passes through the turbulence element, the turbulent dissipation rate in the main flow area is higher, and the particle agglomeration effect is significant. In the vortex street period, due to the viscous dissipation, the dissipation rate decreases exponentially with the increase of the propagation distance, and the agglomeration effect decreases. Due to the resistance of the turbulence element, the pressure drop between the inlet and outlet is up to 143pa, resulting in a large pressure loss.
Study on Prediction of Binder Distribution in the Drying Process of the Coated Web of Positive Electrode for Lithium ion Battery
Authors: Su Yongjian , Zhou Kai , Yuan Yingchun , Liu Weiwei , Deng Yelin
Published: April 2020

The slow and high energy consumption of drying process of the coated web of positive electrode for automotive lithium ion battery have become the bottleneck in the manufacturing process of cathode coating. However, high drying rate of solvent (commonly N-Methyl-2-pyrrolidone (NMP)) result in higher concentration of binder (commonly polyvinylidene fluoride (PVDF)) at the evaporating surface than at the bottom. The uneven distribution of binder between coating layers will lead to the decrease of adhesion between active layer and substrate, and even an increase in internal resistance and the associated deteriorated rate capability, thus seriously damaging the mechanical and electrochemical properties of the electrode. In order to improve the drying efficiency of the coated web, and regulate the concentration distribution of binder, this study mainly calculate the evaporation rate under different drying parameters. and determine the binder distribution at the different evaporation rates.
Application of High-Speed Photography in Amplitude Measurement of a Satellite Antenna
Authors: Liu Zhibin , Sun Gang , Wang Yu , Du Ruizhao , Liu Zhe
Published: April 2020

Spacecraft antenna is an antenna loaded on the spacecraft and an indispensable part of the spacecraft system. It is particularly important to measure the assembly accuracy of the antenna. A certain type of satellite needs to test the amplitude of antenna A and B in sinusoidal vibration test. Because the distance between antenna A and antenna B is very close to the fairing, it is necessary to measure the amplitude of antenna A to verify the spatial compatibility of antenna A with carrier fairing and antenna B in the test process. By comparing four kinds of antenna measurement technology, this paper chooses high-speed photography technology to measure the amplitude of the antenna, uses recognition processing computing technology to binarize the image, changes the image into calculable coordinate value, obtains the amplitude data of X-direction and Y-direction, and verifies the space composite compatibility requirements between antenna A, carrier fairing and antenna B under vibration conditions. There will be interference and collision.
Wall-climbing obstacle-avoiding full-automatic lampblack cleaning device
Authors: Qin Jiarui , Wei Qian
Published: April 2020

With the development of Chinese society and the progress of productive forces, dust and oil stains are easily produced in kitchens and ceilings when living at home. Dirt deposition in many places cannot be carried out well due to the limitation of space location and cleaning methods, which brings great inconvenience to people’s life. At the same time, the existing cleaning robots in the market need to work on a single wall surface, and when encountering obstacles, the positions of the robots need to be adjusted manually to further realize the work and cannot solve the cleaning problems of ceilings and the like. The existing cleaning robots mostly use centrifugal fans to fix on vertical wall surfaces in an adsorption way, thus causing obstacles to be avoided, the connection between different wall surfaces cannot be realized, and the defect that intelligence works on a single wall surface requires manual wall surface replacement, thus reducing automation, intelligence and intelligence. Based on the above background, the members of this group have designed a wall-climbing cleaning machine. The device mainly comprises a walking module, a wall turnover module and a cleaning module [1].
Optimization of extended range electric vehicle energy management strategy via driving cycle identification
Authors: Chen Yong , Zhang Yue , Wei Changyin , Li Guangxin , Li Congcong
Published: April 2020

There are ambitious fuel consumption targets for the manufacturers of heavy-duty vehicles. For this reason, extended range electric vehicle (EREV) is a promising powertrain technology. However, the energy management strategy (EMS) is still an obstacle to the improvement of fuel economy. This paper introduces an energy management strategy for driving cycle identification. Twenty-two typical driving cycles are divided into five categories through Q-type clustering. Euclidean distance is used to identify the driving cycle. For each type of driving cycle, the energy management strategy parameters are optimized through genetic algorithms with fuel consumption and emissions as the goals. The results show that the EMS via driving cycle identification is more effective than a strategy that does not identify it. For comprehensive test cycles, the former’s fuel consumption is optimized by 6%, SOC consumption is optimized by 1%, and there is a slight improvement in emissions.
A momentum-based method for the mass concentration measurement of pneumatically conveyed solid: design optimization
Authors: Liu Guanqing
Published: April 2020

Mass concentration measurement of pneumatically conveyed solid is still challeging in industry. In our previous work (Liu G.Q., The 5th International Conference on Advances in Energy Resources and Environment Engineering, December 6-8, 2019, Chongqing, China.), a novel momentum-based method with more reliable measurement mechanism and simpler structure was developed and computationally validated with a one-end closed straight tube. In this paper, optimization on the structure of the metering tube is conducted to improve the measurement sensitivity represented by the conversion factor k. Tubes with a conical inlet are found to possess higher k than that of the straight tube. Computational fluid dynamics (CFD) computations show that k generally increases with decreasing half-cone angle at fixed radius and decreases with decreasing restitution coefficient of collision between particles and the tube walls.
Genetic analysis of remaining oil in thin and poor layers in Lamadian oilfield
Authors: Liu Wenchao
Published: April 2020

Understanding the distribution of remaining oil and its genesis is the basic work of geological research. Lamadian oilfield has entered the late development stage of ultra-high water cut, the thick oil layer of water drive is decreasing gradually, and the thin and poor oil layer is becoming an important target of adjustment and tapping potential below 1.0m. In order to further improve the development effect of thin and poor reservoir, it is necessary to analyze the saturation field of the numerical model based on interpretation result, core analysis result of sealed coring well and water drive model. The remaining oil characteristics of thin and poor reservoir are studied by means of statistics, genetic analysis, dynamic analysis and static analysis.
State of Health Estimation Framework of Li-on Battery Based on Improved Gaussian Process Regression for Real Car Data
Authors: Xiao Wei , Xu Huachi , Jia Jun , Feng Fei , Wang Wen
Published: April 2020

With the diversification of power batteries in the market, the estimation and management of State of Health (SOH) become more and more important. The building of the models based on experimental data needs much time and many resources, and the models do not have strong versatility. In this paper, a data-driven on-line SOH estimation framework is built by using the measured data of vehicle operating process. In case that the charging data is incomplete and with low precision, an indirect feature (IF) extraction and combination scheme based on Incremental Capacity Analysis (ICA) is built, so as to realize the mapping between IF and SOH based on Gaussian Process Regression (GPR), and Multi-Colony Particle Swarm Optimization (MPSO) is adopted to solve the local optimum of GPR hyper-parameters. Finally, after the algorithm is verified and evaluated by applying NASA (National Aeronautics and Space Administration) dataset and real vehicle data, and when the training amount of operation data is enough, the error of SOH estimation can be controlled within 2%, which shows that the algorithm has good versatility and estimation precision.
Functional preservation and enhanced capacity for visual restoration in subacute occipital stroke
Authors: Saionz Elizabeth L , Tadin Duje , Melnick Michael D , Huxlin Krystel R
Published: April 2020

Stroke damage to the primary visual cortex (V1) causes a loss of vision known as hemianopia or cortically-induced blindness. While perimetric visual field improvements can occur spontaneously in the first few months post-stroke, by 6 months post-stroke, the deficit is considered chronic and permanent. Despite evidence from sensorimotor stroke showing that early injury responses heighten neuroplastic potential, to date, visual rehabilitation research has focused on patients with chronic cortically-induced blindness. Consequently, little is known about the functional properties of the post-stroke visual system in the subacute period, nor do we know if these properties can be harnessed to enhance visual recovery. Here, for the first time, we show that ‘conscious’ visual discrimination abilities are often preserved inside subacute, perimetrically-defined blind fields, but they disappear by ∼6 months post-stroke. Complementing this discovery, we now show that training initiated subacutely can recover global motion discrimination and integration, as well as luminance detection perimetry, just as it does in chronic cortically-induced blindness. However, subacute recovery was attained six times faster; it also generalized to deeper, untrained regions of the blind field, and to other (untrained) aspects of motion perception, preventing their degradation upon reaching the chronic period. In contrast, untrained subacutes exhibited spontaneous improvements in luminance detection perimetry, but spontaneous recovery of motion discriminations was never observed. Thus, in cortically-induced blindness, the early post-stroke period appears characterized by gradual—rather than sudden—loss of visual processing. Subacute training stops this degradation, and is far more efficient at eliciting recovery than identical training in the chronic period. Finally, spontaneous visual improvements in subacutes were restricted to luminance detection; discrimination abilities only recovered following deliberate training. Our findings suggest that after V1 damage, rather than waiting for vision to stabilize, early training interventions may be key to maximize the system’s potential for recovery.