bluuebunny/crossref_metadata_2025 huggingface dataset:
Charging Characteristics of Sulfur powder in Elbow of Pneumatic Conveying System
Authors: Juan Lv , Yu Fu , qiangqiang Lv , Bin Wang , Jianbo Wang , Haiyan Chen
Published: December 2019

Eliminating static electricity is a difficult thing for pneumatic conveying. In this paper, the most representative powder sulfur is selected as the research object. Therefore, in order to study the influence of pipe elbows on the charging characteristics, pneumatic conveying experimental platform was applied to conduct experiments to investigate the synergistic effects of airflow velocity, particle mass flow rate, particle water content and particle size on the charge characteristics, and the optimal ratio of elbow was designed. The results show that, when the particle size was constant, the charge-mass ratio increases with the increase of the airflow velocity, showing a linear positive relationship and increases firstly and then decreases with the increase of mass flow. When the airflow velocity was constant, particles were -40 μm, the effect of particle size on the charge-mass ratio becomes more significant. When the particle size was +40 μm, the charge-mass ratio of sulfur powder increases with the decrease of particle size, the influence is not notable. When the mass flow kept constant, the charge-mass ratio of sulfur powder increases as the particle size decreases. When the water content increases from 0 to 0.4%, the charge-mass ratio decreases by 14.3%-16.9%. However, if the water content continues to increase, the charge-mass ratio is stable. The charge-mass ratio of sulfur powder decreases with the increase of the bend ratio of right-angle elbow. As the technological layout is satisfied, the bend ratio can be increased to the range from 2.5D to 3D appropriately. This research can give reference to the design of sulfur powder pneumatic conveying system, so that the reasonable system ratio can be ensured.
Molecular Simulation of bioalcohol purification in ZIF-1, -3, -7 and -9 frameworks
Authors: Liu Xiuying , Yuan Junpeng
Published: December 2019

Using the Grand Canonical Monte Carlo (GCMC) method, the adsorption properties of ethanol and water on the four ZIFs (ZIF-1, -3, -7 and -9) have been investigated with different conditions. Their storage capacities of pure ethanol and water at different temperatures and pressures have been compared. And the mixture adsorption of ethanol and water and the adsorption selectivity of ethanol over water in these ZIFs have also been investigated. The following conclusions are obtained: (1) the order of the adsorbed amounts of ethanol is ZIF-9>-7>-3>-1 at the same condition. And there are the same trend for water adsorption. (2) ZIF-1 and -3 have preferable selectivity of ethanol over water than ZIF-7 and ZIF-9 owing to the hydrophobic structure of the former.
Dynamic Compensation Control Strategy of PFC Based on Real-time Calculation of Performance Index
Authors: Li Jun , Gao Song , Wang Tao , Sun MengMeng , Lei WenTao
Published: December 2019

The primary frequency control(PFC) performance of thermal power units were affected by the problems such as equipment delay, nonlinear valve flow characteristic curve and weak controller parameters etc. Combined with the new integral electricity contribution index method, one dynamic compensation adjustment method of PFC based on real-time evaluation of performance indexes are proposed. The method dynamically adjust the control parameter by calculating the amplitude of PFC at the relevant time and the integral electricity contribution in the corresponding time period. This method not only improves the PFC performance based on the safe operation of the unit, but also helps to improve the PFC performance. It satisfies the power grid’s standard and reduces the frequency fluctuation of the grid system.
Influence of Pollution Degree on Impact Flashover Characteristics of Insulator
Authors: Chao Yafeng , Zhang Liu , Wang Cheng , Huang Fuyong , Duan Jianjia , Yue Yishi , Liu Sanwei
Published: December 2019

The flashover characteristics of polluted insulators under lightning impulse and switching impulse are simulated in laboratory. It is found that when the gray density value is fixed, the flashover voltage begins to saturate under the shielding failure voltage while the salt density value reaches 0.1∼0.15mg/cm2 And the salt density saturation point under the counterattack voltage waveform is earlier than that under the counterattack voltage waveform, around 0.02mg/cm2. When the gray density value is fixed, under the counterattack voltage waveform, the flashover voltage decreases slightly in the gray density of 0.05mg/cm2 to 0.10 mg/cm2 range, and the flashover voltage begins to rise with the increase of gray density. Under the shielding failure waveform, the flashover voltage always decreases in the gray density of 0.05mg/cm2 to 0.20mg/cm2range, and begins to rise gradually after the gray density exceeds 0.20mg/cm2.
The Auxiliary Electrode Can Improve the Electric Field Distribution of the Roller Electrostatic Spinning
Authors: Hao Shi , Pingjuan Niu , Pingfan Ning
Published: December 2019

Although needle-free roller electrostatic spinning technology has the advantages of higher output than traditional needle electrostatic spinning, it has the problem of uneven distribution of electric field and poor quality of filaments. The emphasis of this study is to solve the non-uniform distribution of the electric field of roller electrostatic spinning so that it can produce high-quality nanofibers. The electric field analysis shows that the electric field distribution is most uniform when (1) ring electrode is connected to 5kv and parallel electrode is connected to 11kv, and (2) auxiliary electrode is connected to -700v. The finite element analysis of the electric field shows that the auxiliary electrode increases the electric field intensity in the spinneret area. The auxiliary electrode in needleless roller electrostatic spinning technology can be used to develop high efficiency and low energy consumption nano-fiber production system.
Passive House Techniques in Retrofit of Conventional Buildings in Northeastern Coastal Regions of China
Authors: Wang Daohua
Published: December 2019

Passive houses provide a comfortable and healthy indoor living environment with low energy consumption and low extra building costs, especially suitable for China with huge population and strong economic growth, so this paper aims to study guidelines and the application of passive house techniques to retrofit conventional buildings in the northeastern coastal regions of China. The key points of design techniques including retrofit of exterior walls, roofs, exterior windows and doors, and natural ventilation are discussed in detail. In the end, this paper looks to the future development of passive houses in China.
Research on comprehensive optimization of engineering project based on non-radial super-efficiency DEA
Authors: Liu Yan , Wang Xiaowen , Ji Yingbo
Published: December 2019

Duration, cost and quality are three important main indexes to measure the comprehensive benefit of the construction engineering project, the comprehensive equilibrium optimization of which is great of significance. With simple process and clear results, non-radial super-efficiency DEA is an algorithm for studying the input and output, which considers the resource constraints and decision-maker preferences. By introducing this algorithm into the field of comprehensive optimization of engineering project, the multi-objective comprehensive optimization model of quality, cost and duration is established and the solution is obtained by using non-radial super-efficiency DEA model, thus completing the order of different construction schemes and realizing comprehensive optimization of engineering projects. Finally, through one application example, the solution is obtained by using LINGO software, which has proved the effectiveness of the optimization method and provided support to the decision-making of the project.
Experimental research on bearing capacity of special anchor
Authors: Feng Shaojie , Hu Hang , Sun Shiguo
Published: December 2019

The bearing capacity of anchor can be greatly improved by adding anchor gills on the basis of traditional anchor. Taking the smaller particle pea stone concrete as anchoring cartridge, this paper conducted the bearing capacity pull-out test on special anchor with additional anchor gills and studied the relationship between bearing capacity of special anchor and layers of anchor gills, strength of pea stone concrete, the size of the block. The test results have revealed that adding anchor gills in anchoring section has an obvious effect on improving the bearing capacity of anchor and the bearing capacity of single-layer rod is 1.2 times - 1.7 times that of finishing rod. There is a non-linear relationship between the bearing capacity of special anchor and the strength of pea stone concrete when the strength of anchor gill is constant. However, as the concrete strength increases, the improvement of bearing capacity becomes smaller. Under the condition of single-layer rod, the bearing capacity of anchor increases with the increase of the size of the block, which shows that the bearing capacity of anchor is positively correlated with the thickness of concrete when the strength of anchor is constant.
Analysis of the vortex characteristics during roadway ventilation
Authors: Qi Yipei , Yang Fan , Zhao Hengze , Wang Fusheng
Published: December 2019

The ventilation in the roadway is in a turbulent state. As the main body of the ventilation, the vortex rotating produces energy dissipation under viscous force which in turn creates air resistance, and it plays an important role in heat and mass transfer. Considering the importance of the vortex in the roadway ventilation, a series of analyses were made by the Taylor model from the perspective of microscopic to explore the vortex characteristics based on the theory of viscous fluid mechanics and vortex motion. The phenomenon that the radii was increasing as vortex diffusing to the roadway center and the energy dissipation was the biggest near the wall was verified. The survival period of vortex was clarified which has an important effect on analyzing the formation of the turbulence. The paper also established the model of energy dissipation rate unit volume which is helpful to the theory of roadway ventilation. In the final, a proposal was offered that it was better to avoid small scale vortex in the roadway ventilation.
Research on TFP change and convergence of China’s regional real estate industry
Authors: Xu Houan , Liu Xinnan
Published: December 2019

The added value method is used to screen the input and output indicators of the real estate industry. The DEA-Malquist method was used to measure the total factor productivity (TFP) of the real estate industry in China’s 30 provinces from 2006 to 2017. Further, the convergence test of the real estate industry TFP in eastern, central and western China was conducted. It was found that the average growth rate of real estate industry TFP in China’s 30 provinces during the period was 3.3%. Technical efficiency was the main driving force for TFP growth, and the contribution of technological progress was relatively small. In the improvement of technical efficiency, pure technical efficiency is obviously improved, and the improvement of scale efficiency is limited. The absolute β convergence test was carried out. From the national perspective, the TFP gap in the real estate industry in each province has a significant narrowing trend; In terms of regions, the TFP gap in the real estate industry in the eastern provinces has a narrowing trend, but it is not significant; The growth of TFP in the real estate industry in the central region has a significant catch-up characteristic, and the TFP gap between provinces has gradually narrowed; The TFP gap in the real estate industry in the western provinces has significantly expanded.
Comparison on seismic response of rectangular closed diaphragm wall and pile group in sloping liquefiable deposit
Authors: Zhang J L , Cheng Q G , Li Y , Wang C
Published: December 2019

This paper presents fully coupled solid-fluid nonlinear dynamic finite element (FE) model on OpenSees platform to study the response of rectangular closed diaphragm wall (RCDW) subjected to earthquakes. Soil seismic behavior was simulated by the PDMY02 soil model available in OpenSees and soil-RCDW interaction was captured by the zero length elements with PyLiq1, TzLiq1 and QzSimple1materials. Then, the FE numerical model was validated by data measured from centrifuge experiments. The validated numerical model was used to investigate the different seismic response between RCDW and pile group in sloping liquefiable deposit. The numerical simulation results showed that: a) Compared with pile group, RCDW can mitigate liquefaction in soil core subjected to earthquakes; b) RCDW was able to resist soil lateral spreading more effectively; c) The shear strain of soil core was restrain by RCDW which resulted in slow generation of excess pore water pressure. Therefore, RCDW had the advantage of liquefaction mitigation; d) Pile group had more deformation displacement, RCDW had more rigid displacement, resulted from the different stiffness and structural integrity between RCDW and pile group; e) Finally, it can be concluded that RCDW may be more suitable choice applied in the sloping liquefiable ground.
Structural characteristics of oak plantation in Danjiangkou reservoir area
Authors: En Liu , Chunqian Jiang , Xudong Zhang , Lianghua Qi , Lei Zhang , Zengwang Yao , Hui Wang , Yanfeng Bai
Published: December 2019

In this paper, the frequency distribution of DBH and DBH of oak plantation was simulated by using normal distribution, and the relationship between DBH and tree height, DBH and crown area was fitted by 11 common curve models. The relation between DBH and tree height was well simulated by S model and cubic curve model. The relationship between DBH and crown area was simulated by cubic and quadratic models.
Geometric Construction and Static Analysis on Timber-Arched Structural System of Shouning Timber-Arched Lounge Bridge
Authors: Deng Hua , Yang Shunli
Published: December 2019

Due to the disrepair, many timber-arched lounge bridges have structural safety hazards and require protection. This paper analyzed the structural composition as well as the composition principle of of Shouning timber-arched lounge bridge. It is found that the timber-arched bridge structure belongs to highly indeterminate. The ANSYS finite element simulation analysis of timber-arched lounge bridge shows that three-node and five-node seedlings are the components which are mainly subjected to axial force. Their shear stress is only 12% of the axial stress. Three-node and five-node seedlings make full use of the tensile and compressive properties of wood. At the same time, the portal framed bent, horse leg also play an important part in the structure. The double bridging is the important component to guarantee the wind resistance, earthquake resistance and transverse stability of bridges. The results of this paper have academic guidance meaning for the maintenance and reinforcement of timber-arched lounge bridge.
Wind Farm Harmonic Impedance Estimation Based on Stochastic Subspace Method
Authors: Jiao Chunlei , zhi Zhao Pu , bing Hou , Zhen Wang , Yongjun Cai
Published: December 2019

Wind farm harmonic impedance is important parameter of wind farm. It has an important influence on stability calculation, stability analysis and stability assessment. To solve this problem that wind farm harmonic impedance is considered as static parameter, an assessment method of wind farm harmonic impedance based on output-error model parameter estimation is proposed. A simplified treatment for the wind farm PCC model is made. The simplified model is transformed into two-node equivalent model. And then the amplitude-frequency characteristic of wind farm harmonic impedance is gained by using the output-error model parameter estimation. The simulation result and outdoor test result illustrate the effectiveness of the proposed method. The proposed method takes a new direction with model identification and system analysis of wind farm harmonic impedance.
Influence of Excavation of Loess Tunnel on Stability of Adjacent Existing Tunnels
Authors: Qianqian Zhen , Shuchen Li , Guangshun Zheng , Xianda Feng , Zhaoming Chi
Published: December 2019

This study investigates a project for new railway tunnels constructed adjacent to existing tunnels in the Loess Plateau region of Taiyuan, Shanxi Province, China. A comprehensive empirical evaluation method and three-dimensional Lagrangian numerical simulation were used to analyze the effects of newly built tunnels on the stability of existing tunnels. Research conclusions are listed as follows. Empirical evaluation method is used to study the construction of the newly built tunnel, which is located within the restricted range of the two existing tunnels and the caution range. When the newly built tunnel is within the restricted range of the existing tunnel, the smaller the distance between the two tunnels, the greater the influence on the deformation of the existing tunnel. When the newly built tunnel is located within the caution range of the existing tunnel, the tunnel contains maximum disturbance in the middle of the axis of the existing tunnel. The results provide a reference for future research on similar adjacent construction.
Buckling of Rock-Socketed Piles Embedded in Soft Soils
Authors: Shao Xianfeng , Chen Ximing , Liu Junxiu
Published: December 2019

Buckling of rock-socketed piles embedded in soft soils is intensively explored by utilizing three dimensional Finite-Element model in this paper. For pile-soil systems with a wide range of values of geometric parameters and material properties, the critical buckling load and buckling mode are obtained, and compared with the results based on Winkler foundation model. The simulation results show that the exact critical buckling load is a little bigger than that based on Winkler foundation model. The effect of rock-socketed ratio on the critical buckling load with three types of constrains is also investigated. With increasing rock-socketed ratio, the critical buckling load increases dramatically. The obtained results are useful to optimize the design of the pile-soil system against buckling in geoengineering applications.
Mechanical behavior evaluation of corrugated steel webs (CSWs) multi-cell PC box girders
Authors: Chen Yitu , Zheng Zhiren , Xu Jing , Ding Yong
Published: December 2019

In order to optimize the design of the girder bridge, based on the CSWs PC box girders bridge design parameter, the mechanical behavior of single-room girder boxes from the single cell to five cells under four different load combinations were analyzed by using the FEA. The mid-span displacement in the bottom flange, Von-mises shear stress in both corrugated web sides, normal warping stress and dead weight of the box girder were obtained. Calculation results have shown that multiplying cell numbers could increase the efficiency of prestressing and decrease the Von-mises shear stress in both corrugated web sides in some cases. However, with the cell numbers increasing, the normal warping stress under eccentric load and the dead weight of the girder increase dramatically. Finally, by utilizing the Simple Formula Method and Principal Component Analysis Method, the proper cell number for the box girder of the specified size is suggested.
Parametric Design and Application of Assembled Steel Plate Composite Beam Bridge Based on BIM Technology
Authors: Hui Wei , Xu Hanzheng , Li Zhifeng , Ma Chaofan
Published: December 2019

This paper combines Building information model (BIM) technology with assembled steel composite beams, carries out parametric design and Deepening Application in Revit software, optimizes BIM technology with other software, proposes parametric design process based on Revit as three-dimensional core modeling software, and carries out virtual analysis of bridge real environment. The BIM information classification and coding of the components of the assembled composite girder bridge lay the foundation for the establishment of BIM information model. Based on Dynamo visual programming, the input efficiency of information integration is improved by batch input of parameter information values. Based on the BIM model and Abaqus finite element software, the stability of the 2×5 m prefabricated pier is verified and analyzed.
The influence rule of highway curve radius on speed perception and operating speed
Authors: Liu Ting , Xu Jinliang
Published: December 2019

In order to understand the influence of the radius of horizontal curve on driver’s speed perception, driving simulation experiments were carried out in the route scene with radius from 400 m to 1000m based on Uc-win/road driving simulation system. The real-time speed and acceleration parameters of the whole section of the vehicle were collected by ECO driver plug-in built in the software, and the driver’s perception speed at feature points is acquired by “inquiry method”. The perceptual speed and actual speed at the feature points are compared and analyzed. The results show that when the roadside environment is monotonous, the perceptual speed of the driver is lower than the actual speed, and the perceptual speed near the entry curve is much lower than the actual speed. However, the radius of the curve has little effect on the estimation error of vehicle speed at the turning point., after the midpoint of the curve, the accuracy of drivers’ perception of speed is gradually improved; when the radius of the horizontal curve is large, the speed of the vehicle is not affected by the radius of the curve.
Research on the Mechanical Characteristics of Long Span Cantilever Casting Deck Arch Bridge
Authors: Jiao Fengzhi
Published: December 2019

In order to study the mechanical characteristics of long span cantilever casting deck arch bridge, taking Jiashi super-large bridge with 225m main span as an example, and the finite element software Midas civil is used to analyze the mechanical characteristics of the completion state of the bridge and the changes of the internal force in each construction stage. The results show that the internal force at each segment of the arch ring is small and uniform when the closing segment of long span cantilever casting deck arch bridge is constructed, which can make the closing operation of the main arch ring safely and smoothly. What’s more, the internal force at the arch feet and vault of the main arch ring is large when the bridge is completed, while the internal force at the two construction segments adjacent to the vault is larger than that at the vault which needs to be paid more attention.
Study on Dynamic Response of Arch Bridge under Vehicle Braking Based on Model Updating
Authors: Gao Guijie , Wang Tao , Li Tao , Li Zhenyang
Published: December 2019

In view of the insufficiency of the current research on special driving, this paper modifies the finite element model based on the static and dynamic measured data, and obtains the benchmark model reflecting the true state of the actual stress state. The influence of braking position and deceleration on key components of arch bridge is studied by establishing the vehicle-bridge coupling model under braking action and choosing three axles to load. The results show that the braking force of vehicle has a great influence on the dynamic response of key parts of arch bridge, and increases with the increase of braking deceleration. At the same time, the influence of vehicle braking force on the arch bridge column is obviously greater than that on the main arch ring.
Modeling Confined Compression on Structured Soils
Authors: Zhu Enyang , Wang Shaokun
Published: December 2019

In confined compression on structured soil, due to the exertion and decay of soil structure, the ratio of horizontal to vertical stresses is low in the earlier compression stage and tends to be the same as normally consolidated soil finally. In order to describe this behavior, the structured unified hardening model (structured UH model) was extended in the following 2 aspects: (1) properly selecting Poisson’s ratio to reflect the stress ratio in earlier compression stage; (2) adding a shape parameter in dilatancy equation to control the stress ratio in final confined compression stage. According to the comparisons between model simulations and test data, the extended structured UH model is qualified in reasonably simulating the stress states of structured soil in confined compression.
Numerical Study of Fire Smoke Exhausting in an Eight-lane Dual-Directional Rectangular Tunnel
Authors: Cao Zhengmao , Liu Xiao
Published: December 2019

In order to obtain the smoke exhausting characteristics of large-span cross section rectangular tunnel under lateral exhaust model, fire numerical simulation calculation was conducted by FDS to analyse the influence of different factors on smoke exhausting efficiency, including the layout, area, and spacing of smoke exhausting valves in immersed tunnels, and the applicability of the different tunnel width under the model of lateral exhaust was studied. The results are as follows: The smoke exhausting efficiency of individual exhausting valve decreases with more exhausting valves opened, but the total smoke exhausting efficiency of immersed tunnel increases. When three smoke exhausting valves are arranged in a group, the increase of distance between groups is conducive to smoke exhausting. The Smoke exhausting efficiency of evenly arranged valves is higher than the ones where three valves are in a group. When the number of exhausting valves opened remains the same, the increase of opening area can increase the total smoke exhausting efficiency because the ventilation resistance reduces. In lateral exhaust model, the increase of the width of immersed tunnel can result in the sharp decrease of smoke exhausting efficiency. In a two-lane, uni-directional immersed tunnel, the smoke exhausting efficiency is 93.7%, and that of a four-lane one is only 45.94%. For the poor applicability of lateral exhaust model in the large-span cross section immersed tunnel fire, it is suggested that additional smoke exhausting measures should be adopted to increase the efficiency of smoke exhausting.
Simulation and Experimental Study on Fracture Properties of Lightweight Aggregate Foam Concrete
Authors: Lu Yao , Yang Xiaofa , Xiao Yiqiang
Published: December 2019

Lightweight aggregate foam concrete (LAFC) is a quasi-brittle porous composite material with a large number of holes and micro-cracks in the internal structure, which directly affect the durability and reliability of the building structure. In this study, the extended finite element method (XFEM) is used to build a fracture performance simulation model of three-point bending (3-p-b) for the LAFC. The crack propagation pattern and the loading force variation law are investigated and compared with the fracture test. The results show that the calculated results are in good agreement with the experimental results, which indicate that the XFEM is an effective method to study the fracture properties of the LAFC.
Research on Construction Control Network Technology of Hydropower Project in Steep Mountainous Area
Authors: Guanming Guo , Hui Xie , Ronhui Lin , Feng Hou
Published: December 2019

Due to the limitation of natural geographical conditions, many hydropower hub projects are built in steep mountainous areas, which leads to difficulties in fabric control network, excessive deformation of side length projection length, long error transmission route, and low precision of control network. The accuracy of the entire control network is difficult to control. This paper discusses the establishment of a planar control network using a high-precision dual-frequency GPS receiver instrument. The elevation control network is built using precision leveling plus triangular elevation measurements. It is proved by examples that the control network established by this method can not only ensure the overall accuracy and overall consistency of the control network, but also achieve economic, rapid and efficient effects.
Study on Rear Row Occupant Injury and Seat Optimization Based on C-NCAP Whiplash Test Method
Authors: Yuhao Liu , Haiming Gu , Yongqiang Wu
Published: December 2019

In the field of whiplash test, there was a lack of regulations for evaluating the protective performance of rear seats. Referring to the C-NCAP front seat whiplash test method, this paper conducted the rear seat whiplash tests of 10 different models. The test results were presented. The reasons for the loss of NIC, Upper Fz and Upper My were analyzed. The optimization methods of the headrest were discussed and Suggestions on the optimization of rear seats were put forward.
Research on Energy Consumption and Carbon Emission for Fabricated Composite Plate in Component Production
Authors: Shang Yanwen , Chen Weijiao , Qiao Chunzhen , Hou Lei
Published: December 2019

This article focuses on the component production stage of industrialized buildings. The factors affecting energy consumption and carbon emission during the production of fabricated composite plates in a factory in Jiangsu province are classified, the calculation formula is arranged, and the proportion of total energy consumption and carbon emission is analyzed. Based on the measured data, the distribution of energy consumption and carbon emission during the component production stage of fabricated composite plate is summarized.
Discussion of active safety countermeasures of motorway work zone
Authors: Chai Hua , Yu Hongxi , Tan Yiming , Sun Xiaohong , Zhang Zhengyu , Tang Junjun
Published: December 2019

A series of comparison analyses of work zone configurations, traffic organizations and work management among China and oversea countries are carried out. Taking into consideration of human, vehicles, roads, environment as well as management factors, the causes of traffic accidents in work zone areas are deeply discussed. Based on road safety in work zone areas, a series of active traffic safety improvement countermeasures for both workers and drivers in work zone areas have been introduced from the respects from traditional safety devices and traffic control measures to information and intelligent measures, which will provide inspires for the improvement of work safety and operation safety in work zone areas.
Economic analysis of condensing exhaust air heat recovery fresh air all-in-one unit in Hangzhou area
Authors: Wang Zhiyi , Xia Cui , Wu Yunge
Published: December 2019

Condensing exhaust air heat recovery fresh air all-in-one unit deals fresh air with the heat of building exhaust air as cold or heat source and it has a high efficiency. In this paper, energy consumption of air source heat pump system which introduced condensing exhaust air heat recovery fresh air all-in-one unit is analysed, and equipment’s static and dynamic payback period of investment is calculated in fixed number of year. In a similar system, condensing exhaust air heat recovery fresh air all-in-one unit has very good application prospects.
Study on the strength of the artificial dam of underground reservoir in Wulanmulun mine
Authors: Kong Xiang-song , Fang Jie , Liu Shuai , Wang Shuan , Xu Zhuang-zhuang
Published: December 2019

In recent years, to alleviate the problem of water loss and severe water shortages in the west of China, the concept of coal mine underground reservoir was put forward, and a series of related research were conducted. At present, it has achieved a large number of engineering application, but the structure and the related parameters of the dam still remain to be studied and optimized. In order to explore the influence of the strength of the artificial dam on the stability of the artificial dam, FLAC3D numerical simulation was carried out based on the geological conditions of Wulanmulun mine and the actual working conditions of the artificial dam in its underground reservoir, and the displacement and stress were analyzed respectively. The results show that, with the increase of the dam strength grade, the displacement level of the dam and its cut decreases, but the stress level increases gradually. Overall, the proposed strength grade of the artificial dam should be C25.
Method of rock mass quality classification in ancient underground engineering based on three-parameter interval grey number
Authors: Zha Youcheng , Wei Xueyun , Wang Junjie , Wang Taiming , Zhao Yuqin , Li Luyao , Sun Yali
Published: December 2019

Rock mass quality classification is an important basis for long-term protection and tourism development of ancient underground engineering, however, the existing rock mass quality classification methods are difficult to apply to the special project of ancient underground engineering. Based on the in-depth analysis of the characteristics of ancient underground engineering and the influencing factors of rock mass quality, an evaluation index system for rock mass quality classification of ancient underground engineering is established by taking the long-term tensile strength of rock and the weathering velocity of rock mass as indicators. Secondly, for the evaluation index value has the character of bounded-but-unknown uncertainty, and in order to avoid information loss in interval numbers, the three-parameter interval grey number theory is introduced, based on the concept of three-parameter interval grey number distance measure, a rock mass quality classification calculation model for ancient underground engineering is established. Then, because of the complexity of ancient underground engineering, the idea of group decision-making is introduced, and based on the variation coefficient method, the weight calculation method of evaluation index is established to improve the reliability of weight calculation. Finally, a rock mass quality classification method for ancient underground engineering based on three-parameter interval grey number is established. The method is used to analysis the practical engineering, it shows that the method proposed here is feasible and reasonable.
A study on vegetation community and plant species diversity of Yeli Island, Zhuhai, China
Authors: Liu Hui
Published: December 2019

The vegetation of Yeli Island is of great importance to biological and cultural diversity and to the ecosystem services of Zhuhai. To understand the vegetation ecology, vegetation development process and vegetation structure of Yeli Island, a detailed vegetation investigation was conducted on the Yeli Island through line survey and sampling survey methods. Analysis of woody plant population structure and plant species diversity were conducted. Vegetation on this island was relatively simple since it had been once destroyed. It was mainly covered by artificial Acacia confusa. The upper layer was filled with Acacia confusa and the lower was filled with small trees, shrubs and a few herbs. The dominant population of Acacia confusa was gradually degraded, and a series of newer secondary communities had been formed in the lower layer. The index of biodiversity was low. The vegetation quality was not high. Positive measures should be taken to promote the recovery of this community.
A Study on the Traveling Capability of Large Operating Buses on Mountainous Highways
Authors: Jie Zhang , Yu Zhang , Juwei Wu , Yan Mao
Published: December 2019

This paper analyzes the pass principle and influencing factors of large operating buses. The dynamics model of large operating buses is constructed by Trucksim vehicle dynamics simulation software, and computer simulation is carried out. Finally, through the actual scene test of large operating buses and aerial photography observation by drone, the effectiveness of the method is verified. Results of this paper may have some referential significance for improving the safety ability of large operating buses on mountainous highway and reducing the risk of serious road traffic accidents.
Chloride ion Erosion of Cracked Concrete under Load
Authors: Zhang Yunguo , Han Yue , Zhang Junjun
Published: December 2019

In order to study the effect of load on chloride ion erosion before cracking, cracking critical state and instability failure state, three-point bending beam fracture test was carried out. The specimens were loaded at three loading levels: pre-crack load, crack load and peak load, then chloride ion content in the cracked section of the concrete was measured by borehole sampling method after immersion in 8% sodium chloride solution for 30,60,90 days. The test results show that at the same depth of cracking section, the content of chlorine ion increases with the load level. The chloride ion content with wedge erosion is significantly higher than that without wedge erosion under the same conditions and the increasing trend of chloride ion content under peak load is more significant. The chloride diffusion coefficient decreases with erosion time when the load is less than the initiation load, and chloride ion diffusion coefficient increases slowly with erosion time when load is greater than the initiation load. The stress intensity factor of concrete is positively correlated with chloride ion diffusion coefficient.
Research on the Present Situation and Countermeasures of Carbon Emission in Beijing, Tianjin and Hebei
Authors: Ge Xintong , Cai Linlin , Chang Zhaopo , Wang Xianlei
Published: December 2019

Resource and environmental issues are one of the bottlenecks restricting China’s economic and social development. Adhering to carbon emission reduction and green development is a top priority for the development of Beijing-Tianjin-Hebei. This paper analyzes the data of Beijing-Tianjin-Hebei carbon emissions and its main influencing factors in the past 20 years. On this basis, it sorts out the existing energy-saving and emission-reduction policies and plans of Beijing-Tianjin-Hebei, and clarifies its shortcomings. Furthermore, it proposes countermeasures from five aspects: changing concepts, enacting regulations, green transformation, green finance, and population regulation.
Dynamic evaluation and trend prediction of environmental sustainability in Jiangxi Province based on pollution footprint
Authors: Zhang Qiugen , Wang Hongli
Published: December 2019

Based on the calculation results of pollution footprint, environmental carrying capacity and pollution deficit/surplus in Jiangxi Province from 2004 to 2015, the environmental sustainability was dynamically evaluated in Jiangxi Province from 2004 to 2015 based on a designed environmental sustainability standard with the ratio of pollution deficit/surplus to environmental pollution footprint. It was shown that Jiangxi Province was in the pollution surplus status during 2004 to 2015, which was derived from solid waste pollution surplus and atmospheric pollution surplus, while the water environment has been in pollution deficit. It can be seen that the environmental sustainability of Jiangxi was middle from 2005 to 2007 and strong from 2008 to 2015. Meanwhile, a pollution footprint prediction model (y = -8260.6x
2 + 62750x+ 5×106.) was built to predict the pollution footprint trend of Jiangxi Province in the next five years, and that based on the environmental pollution footprint of Jiangxi Province from 2004 to 2015. It showed that the pollution footprint of Jiangxi Province would drop from 4563473.60 hm2 in 2016 to 3889286.40hm2 in 2020.
The Design and Application of Information Management System Based on IOT for Precast Concrete Segments
Authors: Yu Zhenhuan , Wei Yongbin , Cao Zhen
Published: December 2019

Metro shield tunnels have been widely used in Metro construction. The pre-cast concrete segments of shield tunnels are important prefabricated components in the construction of metro shield tunnels. The quality of segments is directly affected the quality of shield tunnels. In the construction process, a large number of precast concrete segments should be installed and some segments should be formed into rings, so manufacture management, carriage management and constructing of precast segments also directly affect the efficiency and quality of construction. Therefore, it is very important to establish an information management system for precast concrete segment through Internet of Things technology. The system would provide manufacture management (including concealed acceptance, quality inspection, and production-inventory), carriage management (including pre-delivery management, transportation tracking) and construction management (including quality inspection, warehousing management, installation management).
An assessment of recreational value of Color-leaf forest in Bipeng Valley Scenic Spot
Authors: Lu C T , Liu X , Deng Z M , Lin P J
Published: December 2019

This study uses the travel cost method (TCM) and the tourism market demand curve to evaluate the recreational value of the Color-leaf forest resources in Bipeng Valley Scenic Spot at the first time, which contributes to the utilization and management of the Color-leaf forest resources, and also discusses the importance and value of forestry resources. The results show that the research value of the research and development of the Color-leaf forest resources was 1567.48 million Yuan, which is 13 times the actual income of the Bipeng Valley Scenic Spot. It means scenic spot should avoid idle resources, improve its product mix and protect the Color-leaf forest resources to realize the sustainable use of forest resources of arid and semi-arid area of sichuan province.
Research on Intelligent Control System of A/A/O Process for Wastewater Treatment Pilot Based on ASM2D and Fuzzy Model
Authors: Ding Binbin , Zhang Xiaowen , Bo Tao
Published: December 2019

The paper focuses on the design and implementation of intelligent control system for actual wastewater treatment. The objective of this project is to develop an intelligent optimization control system for biological process based on on-line sensing parameters. The control logic of system based on the simplified ASM2d model and fuzzy logic. The system integrates data input and output modules, simulates the biological reaction, and optimizes the control parameters of biological treatment process, such as controlling aeration, dosing and internal reflux ratio. Real-time intelligent optimization control system optimizes the operation effect of wastewater treatment, ensures the water quality to reach the standard and achieves the goal of energy saving and consumption reduction.
Application Analysis of Artificial Environment Control System with Ultra-miniature UAV
Authors: Yu Wenhong , Niu Xiaojie , Wang Kuan
Published: December 2019

In recent years, with the continuous development of building energy-saving technology, people are more aware of adjusting the energy-saving situation of air-conditioning system or heating system from the aspects of indoor thermal comfort and human thermal sensation. The key problem is that the thermal comfort of human body is constantly changing in the process of moving building space. Therefore, this paper puts forward a kind of assembled artificial environment control system with ultra-micro Unmanned aerial vehicle (UAV). It can adjust the thermal comfort of human body locally, reduce the running energy consumption of heating/cooling equipment, and realize building energy saving under the condition that human body can obtain the same or even better thermal comfort environment.
Experimental Research on Indoor Thermal Environment Control and Work Efficiency
Authors: Yu Wenhong , Dong Nana , Jiang Chaowen
Published: December 2019

In order to explore the relationship between work efficiency of office staff and human thermal sensation index PMV, in this paper, the method of combining experimental test and subjective evaluation is adopted to bring seasonal preference into the research scope of work efficiency, and the experimental data are analyzed by quadratic regression. It was found that the highest working efficiency of indoor staff did not appear in the thermal neutral state, but in the preferred environment. Subjects preferred slightly warm indoor environment in heating season and slightly cool indoor environment in transition season. This paper can provide some reference value for the study of the factors affecting the work efficiency of indoor staff.
Effects of Biogas Residue Organic Fertilizer on the Yield and Quality of Dragon Fruit
Authors: Huang Xiaohong , Jiao Jing , Li Zunxiang , Jihua Du
Published: December 2019

In order to explore the effect of biogas residue organic fertilizer on the yield and quality of dragon fruit, field experiments were carried out in comparison with traditional fertilization and cattle manure organic fertilizer to provide technical support for the application of biogas residue organic fertilizer in dragon fruit production. The results showed that the yield per ha and sugar-acid ratio of dragon fruit treated with biogas residue organic fertilizer increased by 12.84% and 60.55% respectively compared with the traditional fertilization treatment, and the VCR (vario-cost ratio) value reached 4.95. Compared with cattle manure organic fertilizer, the yield per mu and sugar-acid ratio of dragon fruit increased by 9.82% and 5.58%, respectively, with a newly increased income of 11,900 RMB/ha. Therefore, biogas residue organic fertilizer has a good application prospect in pitaya cultivation.
Risk Analysis and Intervention Policy Research of Miners’ Unsafe Behavior Based on System Dynamics
Authors: Nannan Qu , Han Ren , Qinggui Cao , Yunna Wang
Published: December 2019

With the application and development of the discipline of safety science and safety economy in enterprises, people gradually began to realize that the unsafe behavior of employees themselves is an important source of coal mine safety issues. This paper constructs a behavioral risk model based on the employee behavior risk in coal mines combined with ALARP principle, and establishes a coal mine safety production organization behavior expectation utility model based on von Neumann Morgan Stan’s utility function. Based on this risk model, employees at different stages are Risk attitude analysis of risk appetite, using Vensim software to construct the model of unsafe behavior level of coal mine workers, and obtaining the trend of unsafe behavior level of coal mine workers through model simulation. Based on the simulation results, the behavioral risk management decision research is carried out to realize the behavior of coal mine employees.
Discrete element simulation and parameter selection about triaxial test of cohesive soil containing calcareous nodules
Authors: Monong Ba , Daoxiang Wu , Lei Ye , Jiacheng Guo
Published: December 2019

Based on the discrete element method, the relationship between the microscopic parameters and the actual macroscopic parameters is introduced. In this paper the method of calculating the corresponding microscopic parameters of cohesive soil containing calcareous nodules is discussed, and the numerical model is established by using the solved parameter results. Numerical simulation results show that: the numerical model of cohesive soil containing calcareous nodules is basically consistent with the stress-strain curve of the actual triaxial test results, and has a high similarity. On this basis, the mechanism of the effect of calcareous nodules on the mechanical properties of soil on the mesoscale scale can be further discussed.