bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Gyro Shock-damping Tool combining with PDC bit in granite buried hill formation in Chad
Authors: Shi Libao , Zhang Xiaoning , Nie Hongfang , Zhang Yanna , He Zhenguo , Kong Lulin
Published: August 2019

Stick-slip vibration is likely to occur while drilling in hard formation and soft-hard interbedded formation, especially when PDC bit is used, which further results in lower ROP and short footage. In this study, Gyro Shock-damping Tool and optimization PDC bit design were tested to reduce the stick-slip vibration and lengthen bit life while drilling in granite buried hill formation. Main parameters of the PDC bit include: 8 blades, short parabolic profile, Trident IV PDC, 10mm, 13mm cutter, totally 90 cutters, back rake of 19°-23°, double row of cutter (back row is impregnated string, with the height difference of 0.5mm). Gyro Shock-damping Tool combined with customized PDC bit was tested in 630-869m granite formation of a well in Chad, 239m footage was done in 54hrs, with a ROP of 4.44m/hr. In comparison, in an adjacent well, only 11m footage was completed with 3 PDC bits at the ROP of less than 1.23m/hr. Compared with some other adjacent wells drilled by 43 tri-cone bits, the specially designed bit increased by 97.33% in ROP and 54.19% in footage on average. All these prove that the technology outperforms the other bits, and can be used widely in granite buried hill horizontal well, hard formations and hard –soft interbedded formations.
Environmental cost assessment model of land use Project
Authors: Guo Jiaxi
Published: August 2019

With the improvement of human understanding of ecological environment, scientists at home and abroad have established a series of models to assess the environmental costs of land use projects. Most of the domestic research is based on the ecosystem of Xie Gaodi’s Static value model. His model mainly considers the value of the ecosystem occupied by the project. However, on the basis of this model, this paper will construct the environmental degradation model from another angle. The new model takes into account not only the value of the ecosystem occupied by the project, but also the continued loss of the project to the external environment. This model is a more comprehensive assessment of the cost of environmental losses for land-use projects.
Research on Rheological Properties of Rockfill Material under Stress Unloading
Authors: Li Jie , Jin Zhuan
Published: August 2019

A number of super high earth-rock dams will be built in China in the near future. Deformation control is the key issue in the safety construction and operation of these major water conservancy projects.In this paper, the effect of stress loading process on the subsequent rheological development is studied, and a new accumulation rule of rockfill rheology is proposed, that is, the current rheological variable of rockfill unit at a certain time is equal to the hardening rheological variable that can cause additional hardening of rockfill at that time.Then, the influence of stress unloading process on the subsequent rheological development law is further studied. It is found that after stress unloading, there are positive rheological zone, no rheological zone and reverse rheological zone in the rheological behavior of rockfill material. The rheological accumulation rule proposed in this paper is also applicable to the case of stress unloading.
Research on fine-grained pattern recognition based on attention pattern-generated model
Authors: Zhou Jiayin , Feng Kaiping , Luo Lihong
Published: August 2019

The major difficulty in classifying the type of fine-grained patterns is that the visual differences between subordinate types are probably very subtle, which, however, may be extremely big in the same kind. A fine-grained pattern recognition algorithm is put forward based on the attention pattern-generated model in this article. First, extract high dimensional characteristic pattern from the image via CNN. Then apply several separators to outputting category predictive activation volumes on the characteristic mapping. After that, polymerize these activation volumes to obtain attention mapping. As for the fine-grained recognition, we use the generated attention pattern to tailor and zoom the intentional area so as to carry out multi-scale prediction. This article has been assessed on CUB-200-2011, FGVC-Aircraft, Stanford Cars, and the model mentioned in this article is more superior than baseline multi-scale resnet50 by more than 2%. Attention pattern generated from the model is helpful for other models to increase their recognition accuracy as well.
Subduction and closing evolutionary mode in western Xar Moron suture zone
Authors: Du Xianli , Shan Xuanlong , Yi Jian , Wang Jiuwen , Dai Xiaojuan , Su Siyuan , Lou Hong , Feng Xin , Liang Ye , Zhang Yunhe
Published: August 2019

The Xar Moron suture zone is located on the suture of North China Craton and Siberian Craton, which is one of the research hotspots in the Geoscience. In this paper, the western section of the Xar Moron suture zone is taken as the research object. Based on geological and geodynamic analysis, the tectonic and evolution stages of the study area were divided, the evolution model of the subduction and closure of the Paleo-Asian Ocean in the study area, the collision of plates and plates is established. The results show that Xar Moron fault is a suture, and there are obvious differences between the crustal structures on both sides of the fault, outcrop volcanic rocks are distinguished by high potassium calcium alkaline series and their magmatic source is a mixture of crust source and mantle source. The study area is divided into four tectonic evolution stages, C2-P2, P2-P3, P3-T3and After T3stage. It is estimated that in the late Permian to early Triassic, Paleo-Asian Ocean has experienced the post-arc dilation, the arc-continent collision and the pre-arc accretion stage. It established the subduction and closing evolutionary mode of the Paleo-Asian Ocean in the Xar Moron suture zone, which provide a reference for the study of the dynamic mechanism of the formation of the fault zone.
Effects of Tillage Practices on Soil Fertility in Loess Plateau
Authors: Meng Tingting , Sun Zenghui , Cheng Jie
Published: August 2019

In order to determine whether there is a threat to soil nutrient content by long-term no-tillage cultivation in loess plateau, a suitable high-yield and high-efficiency tillage technology system is established. This study was conducted in the Changwu Loess Plateau Agro-ecological Experiment Station of the Northwest A&F University in Changwu County, Shaanxi Province. The experimental field for no-tillage cultivation was selected for three consecutive years. In September 2015, no-tillage and tillage were carried out separately before winter wheat planting. And rotary tillage 3 kinds of farming treatment. After harvesting of winter wheat in 2016, the contents of available phosphorus, available potassium in 0∼30 cm soil layer under different tillage methods were analyzed. The results showed that in the 0∼30cm soil layer, the contents of available phosphorus and available potassium in the soil under three tillage methods decreased along the profile. The contents of available phosphorus and available potassium in 0∼10 cm soil layer were significantly higher than that of tillage and rotary tillage (p<0.05). The contents of available phosphorus and available potassium in soil of 10∼30cm soil were ploughed tillage > rotary tillage > no-tillage, and there was no significant difference among the three tillage methods in 10-20cm soil layer.
Geographical Distribution of Characteristic Towns in Zhejiang Province
Authors: Yang Chen , Xin Jinguo , Yang Yang
Published: August 2019

To analyse the geographical distribution of characteristic towns in Zhejiang province. A total of 143 provincial-level characteristic towns in Zhejiang Province were used as research samples to establish a geographic information database. Based on the relevant theory of characteristic towns, the basic statistical analysis was carried out by using e Excel, and the spatial distribution characteristics of characteristic towns were discussed by using the nearest neighbour index, geographic concentration index method and kernel density estimation method. The basic statistical results show that recent domain ratio is R=0.901<1, and the actual geographical concentration index (G1) is larger than the evenly distributed geographical concentration index

(

G
¯

1

)

, so the characteristic town in Zhejiang Province tend to aggregate distribution. The spatial distribution of different types of characteristic towns is significantly different. It is necessary to attach great importance to the uneven distribution of spatial characteristics of characteristic towns in Zhejiang Province. The analysis of the spatial distribution of characteristic towns can provide a theoretical basis for optimizing the spatial layout of characteristic towns.
Oil-water mutual driving microscopic simulation research on low permeability reservoir
Authors: Cao Rongliang
Published: August 2019

Oil-water mutual driving microscopic characteristics of the low permeability reservoirs are analyzed for the example of the H area in Qaidam Basin. The reservoir lithology and pore characteristics are studied by thin section observation, scanning electron microscopy (sem), physical property analysis and mercury injection experiment, etc. Then oil-water mutual driving microscopic simulation is studied by the experiment system device. It indicate that it is poor reservoir property, strong heterogeneity, rock types are mainly lithic arkose and arkose, reservoir space is mainly primary intergranular pore, pore throat characteristics are wide distribution, poor sorted, there are many distribution types and dispersed. Flow of crude oil in the reservoir rocks is non-darcy seepage, start-up pressure gradient is reduced along with the increase of permeability, but the correlation is poor, increase pressure gradient can make the single phase oil seepage achieve linear flow. It is the non-uniform displacement process, the microscopic heterogeneity is strong and the original oil saturation is low; Water flooding breakthrough rapidly along one or two channels, water-free oil production period is short, the efficiency is low, it can increase the water displacement efficiency by increase the pressure, but the effect is not obvious. The residual oil are flow around oil, oil film and the residual oil at the edge of the corner, the formation mechanism is different.
Study on the evolution of paleo-uplift in southeast Sichuan
Authors: Deng Yamei , Liu Xindong , Zhang Junyi , Wang Jianbin
Published: August 2019

The deepening understanding of the geological structure of large paleo-uplift in the basin is often accompanied by important oil and gas exploration discoveries. The abundant oil and gas exploration results in the early stage show that the luzhou paleo-uplift is one of the important petroleum accumulation structural units in the sichuan basin. At the same time, the formation and evolution of luzhou ancient uplift were also affected by a variety of geological factors. It is a joint response of the internal deformation of the Yangtze plate and the orogenic movement of the peripheral block in the indosinian period, and a natural place to study the basin-mountain coupling relationship and the basin superposition transformation process. By means of a large number of seismic reflection profile and drilling data, combined with field exploration and other data, the temporal and spatial distribution characteristics of luzhou ancient uplift are described in detail. Combined with the tectonic background of the study area, the formation of luzhou ancient uplift was further analyzed, and the genetic mechanism model of luzhou ancient uplift was proposed. Through analysis, it is concluded that the indosinian luzhou ancient uplift developed in the southeast of sichuan basin, and its long axial strike is from northeast to southwest, which is a typical compressive and superimposed ancient uplift.
Structural Optimization design of marine hydraulic Tube clamp
Authors: Cai Biaohua , Wang Haisheng , Fang Chao
Published: August 2019

The layout design and structure design of rubber elastic tube clamp have a direct impact on the vibration and noise characteristics of pipeline system, as well as the fatigue life of tube clamp itself and related parts in pipeline system. It is a typical multi-objective optimization design problem. How to design an elastic tube clamp that meets the requirements of stiffness, strength and fatigue life at the same time is an important issue in the design of marine pipeline system. In this paper, the structural optimization of rubber elastic tube clamps is studied by using the non-linear multi-objective topology optimization method.
Studies on the Stress Distribution Features and Changing Rules of Surrounding Rock of Roadway under Isolated Coal Face
Authors: Wu Pengpeng , Li Peng
Published: August 2019

With the development of society and the progress of science and technology, people’s living standard has been raised gradually. Behind these, it the development and utilization of energy. China is a large coal production country. Coal is the basic energy in China, and will be the major energy in the current decades and even in the coming decades. As coal is a non-renewable resource, plus the irrational exploitation in the first few years, a great deal of coal resources were wasted, which is contrary to the sustainable development strategy of the country. In recent years, to respond to national policies, vigorously promote sustainable development strategy, improve energy efficiency, major mining areas are enhancing the mining of residual coal, especially in isolated island state of coal. At present, there are some effective safety measures for mining coal under the condition of isolated island in China, but most of the safety research focuses on the mining face, but only a few studies focus on the safety of roadway. Through investigation, it is found that there are a series of problems in roadway driving and working face mining, such as strip wall and coal cannon. This seriously restricts the mining speed of isolated island working face, and always threatens the safety of workers. In this paper, the stress distribution characteristics of coal body under isolated island state are analyzed by numerical simulation. On the basis of this, the stress distribution characteristics of roadway surrounding rock and working face mining are analyzed, and the stress variation law is summarized. It is found that there exists a stress concentration zone in the coal pillar under the condition of isolated island. The stress concentration zone is mainly affected by the geological conditions of isolated island. There is a second stress concentration zone 7 m away from the side of the roadway, which is smaller than the stress concentration zone in the protected coal pillar, but the dynamic change is larger and the stress concentration zone moves with the advance of the working face because of the influence of mining in the working face. Therefore, in the aspect of maintaining the stability of roadway surrounding rock, the effective maintenance mode is determined according to the stress distribution characteristics and variation law of roadway surrounding rock under isolated island working face.
Research on Electrical Automation Control System and Design Based on Geographic Information Technology
Authors: Han Zhihao , Guo Rui , Han Jinxiang
Published: August 2019

As the pace of power plant construction accelerates, higher requirements are placed on the application performance of the control system. From the current development status of the current electrical control system, it reflects the characteristics of multi-function, miniaturization and intelligence, and provides an important guarantee for the reliable operation of the electrical system. This paper analyzes and studies GIS in geographic information technology and power system application. The structure and function of electric power GIS system are designed. According to the structure and particularity of distribution network, a new distribution network database model is established. The overall planning and design of the network information database are carried out. The design idea of electric automation control system is discussed, and the development trend of electric automation control system in the future is prospected.
Application Analysis of Oil Test Fracturing Technology in Deep Gas Wells
Authors: Zhong Lin
Published: August 2019

In the process of oil exploration, it is necessary to define the general orientation and distribution of underground reservoirs through oil testing and fracturing operations, and to obtain the specific conditions of detailed crude oil reservoirs. Because of the characteristics of high temperature and high pressure of deep gas, it is difficult to test and fracturing deep gas wells. Based on the analysis of the characteristics of deep gas and the development needs of oil testing technology, this paper analyses the oil testing and fracturing technology of deep gas wells through reservoir modification and fluid drainage.
Research on Fracturing Effect of the Second Kind of Oil Layer Weak Alkali Ternary Composite Flooding
Authors: Wang Shuxia
Published: August 2019

The main reason for the low production of oil wells in the second type of oil wells is the poor development of the oil layer itself and the near-wellbore pollution caused by the scaling of the ternary composite system. By analyzing the dynamic and static factors affecting the fracturing of the production well, it is known that the fracturing effect is better when the formation pressure is higher than the saturation pressure after fracturing; the effective thickness is greater than 5 m, the first type of connectivity is greater than 30%, and the high water flooding thickness ratio is less than 40%, production liquids with a drop of more than 20%, a water cut of more than 5%, and a chemical flooding degree of less than 15% can achieve better oil and precipitation effects. For the weak alkali ternary composite flooding type II oil layer with permeability greater than 100×10-3μm2, the conductivity of fracturing has little effect on the fracturing effect, and the fracturing timing is the key factor to determine the fracturing effect.
Dynamic Modeling and Simulation of a Parallel Locking Mechanism
Authors: Xiang Chao , Li Baoren , Gong Yajun , Zeng Baoping
Published: August 2019

Aiming at the locking problem of the mechanism in face-to-face contact, a kind of parallel mechanical locking device is designed, which can make the locked surface self-locking even when the locking hydraulic system fails, thus ensuring the safety and reliability of the locked mechanism. Through theoretical analysis and dynamic simulation of ADAMS software, the self-locking function of the device is verified and the self-locking Angle is calculated. Meanwhile, considering that the locking device may act as a “resonator” and cause secondary excitation to the locked device, which affects the vibration characteristics of the locked system, the mode analysis of the locking device is done by using ABAQUS software, and the feasibility of the locking device for the locked mechanism excited by low frequency is proved.
CFD Simulation on Leakage and Explosion Accident of Liquefied Hydrocarbon Loading Station and Dynamic Responses Analysis of Control Room
Authors: Gu Meng , Ling Xiaodong , Du Kaituo
Published: August 2019

Considering the dangerous characteristics of Liquefied hydrocarbon loading station, a three-dimensional model of a certain liquefied hydrocarbon working area was established to simulate the accident of liquefied hydrocarbon leakage and vapour cloud explosion, and the relationship between the number of loading vehicles and explosion overpressure was analyzed. Meanwhile, the existing control room is not designed for anti-explosion, and the personnel are relatively concentrated, so the dynamic response of the control room under explosion loading needs to be analyzed. The researches show that due to the blocking effect of propylene substation on the combustible gas cloud under north wind, the equivalent stoichiometric cloud mass is higher than that in the southwest wind direction. The blocks in the working area are mainly distributed along the east-west direction, so the peak overpressure of the propylene substation is smaller than that of the control room. There is a linear relationship between the loading vehicles and the explosion overpressure in the control room. With the decrease of the number of loading vehicles, the explosion overpressure decreased significantly. If the number of loading vehicles is not reduced, the brick wall of the existing control room will be broken and collapsed under explosion loading, threatening the safety of personnel in the control room.
Study on The Characteristics of Temporal and Spatial Changes of Regional Water Resources
Authors: Zhang Haiou
Published: August 2019

In order to accurately reflect the basic characteristics of the water quality of the different reaches of the Weihe River (Shaanxi section), this paper selects ammonia nitrogen, CODcr, total phosphorus, and total nitrogen, which are more serious and concerned about exceeding the standard in the surface water of the Yellow River basin based on a large number of survey data, draw the curve of four water pollution indicators along the Weihe River (Shaanxi section) in different water periods, and grasp spatially the environmental changes of different parts of the Weihe River (Shaanxi section), different upstream and downstream parts. And the contrast of quality changes, so that the river water quality evaluation is typical and representative, provide a basis for the comprehensive management of the Weihe River basin, and promote the sustainable development of the Guanzhong region.
Text Classification of Potential Dangers in Coal Mine Safety Based on Convolutional Neural Network
Authors: Liu Na , Hu Yanzhu , Ai Xinbo , Shao Yanchao
Published: August 2019

In recent years, with the improvement of people’s safety awareness and the steady progress of safety production supervision, text classification algorithm based on data mining has been widely applied. At present, for the classification of hidden danger text in coal mine, it mainly relies on manual or machine learning. The efficiency of manual classification is too inefficient to meet the requirements of massive text classification. And the accuracy of machine learning-based classification method is low. In view of the above problems, this paper combines Word2vec and convolutional neural network to achieve accurate classification of hidden danger text in coal mine safety, and achieves great results. The results show that Word2vec can retain the semantic information between contexts. Convolutional neural network can effectively extract the high-level features of local contexts, and the classification effect is more accurate. This method can be implemented in the classification of hidden danger text in coal mine, which has very important practical significance.
Pre-stack Depth Migration based on VTI Media in Common Shot Domain
Authors: Song Liang , Guo Tianzhi
Published: August 2019

With the increasing complexity of seismic exploration targets, the basic imaging theory based on the basic assumption of simple isotropic media cannot meet the actual needs of oil and gas exploration at this stage. Therefore, the study of imaging methods in anisotropic media is of great significance to the exploration of various underground structures and mineral exploitation. In this paper, the SSF continuation operator for VTI anisotropic medium is derived and the one-way prestack depth migration with VTI media in common shot domain is realized. The VTI-HESS model is verified by calculation. Compared with prestack depth migration of various isotropic media, it can be seen that prestack depth migration of VTI media has better imaging effect because of considering anisotropic parameters, which is closer to the actual imaging effect of exploration data.
Applying of soft rock to control Mu Us sandland: A case study of Yulin City
Authors: Cheng Jie , Wang Huanyuan
Published: August 2019

In order to alleviate the contradiction between people and land, improve the quality of cultivated land and the ecological environment of the land, this paper studied the sand-fixing characteristics of soft rock by indoor experiments and promoted the field. The results showed that the complementarity of the soft rock and sand in the particle size composition, the two had mixed with the composite soil to form a good particle size distribution, increased the grain roughness, and had a sand-fixing effect, improved the porosity of the sand at the same time. The increasing of the content of clay increased the water retention and water retention of the sand and reduced wind erosion. Based on this sand-fixing mechanism, the practical application of arsenic sand-fixing in Daji Khan Village, Yuyang District, Yulin City had been carried out by means of soil-body reconstruction project of soft rock and sand, water, road and forest supporting projects, and the control effect is remarkable.
Multiphase Flow Law and Well Control Risk Analysis in Deep Water Gas Hydrate Horizontal Well While Drilling
Authors: zhang Yangyang , Tang Zhiqiang , Duan Wenjiang , Si Menglin
Published: August 2019

Natural gas hydrate is an important clean energy in the future because of its high energy density, clean and pollution-free, large amount of resources and wide distribution. However, the gas hydrate reservoir in the sea area has the characteristics of deep water depth and shallow reservoir buried depth. It is difficult to develop, and the development cost is high, so it is difficult to meet the needs of commercial exploitation. Horizontal well drilling can ensure reservoir drilling rate, increase reservoir drainage area and improve development efficiency. During the drilling process of deep water gas hydrate horizontal wells, the gas hydrate is decomposed into gaseous gas due to the change of temperature and pressure environment. The multiphase transient flow of gas in the wellbore will affect the wellbore temperature and pressure environment and cause well control risk. The calculation model of multiphase transient flow and temperature field in drilling wellbore of deepwater gas hydrate horizontal well and the model of gas hydrate formation were established. The gas distribution, migration law and temperature and pressure distribution in wellbore were analyzed, and the variation of wellbore pressure, surface flow law and temperature and pressure range of gas hydrate formation were grasped, which will provide theoretical basis and construction reference for deep water gas hydrate horizontal well drilling.
Remote Sensing Image Registration Algorithm Based on Multi-scale Corner and Haar Transformation
Authors: Yang Yanli , Liu Zhiguo , Zhang Jinsheng
Published: August 2019

This paper proposed a new image registration algorithm based on multi-scale corner and Haar transformation, which its core idea is the combination of Haar operator and the Laplace image pyramid are used in down sampling the original images, and detect corner at the resulting images, Angle of the corner and most value point of scale response (scale precision positioning) will get, registrating images will obtained after rotation and translation. Theoretical analysis and simulation results shows the algorithm has higher registration accuracy and small amount of computation.
Evolution characteristics of soil carbon density after homestead remediation
Authors: Guo Zhen , Li Juan , Shi Chendi , Wang Huanyuan
Published: August 2019

In order to gain an in-depth understanding of the effects of different reclamation years on soil carbon sequestration after remediation of abandoned homesteads, this study relied on the land improvement project carried out in Changchun County, Shaanxi Province, to study the soil carbon density of different reclamation years. The results shown that the total carbon and inorganic carbon content of 0-20cm and 40-60cm soil layers increased steadily with the extension of cultivation time after the rectification of abandoned homesteads. In the 20-40 cm soil layer, the soil total carbon and inorganic carbon content increased firstly, then decreased and then increased with the extension of the cultivation period, especially the total carbon content changed the most. In the 0-40 cm soil layer, the organic carbon showed a tendency to decrease first, and the change trend of the organic carbon content in the 40-60 cm soil layer increased first and then decreased. The trend of carbon density changes was consistent with the trend of carbon content. After 10 years of reclamation compared with before the renovation, soil total carbon and inorganic carbon density increased by 22.93% to 47.72% and 16.11% to 45.30%, respectively, the regularities of vertical distribution was 40-60 cm > 0-20 cm > 20-40 cm. The density of organic carbon increased by 41.12% to 68.27% compared with before the renovation, and the regularities of vertical distribution was 0-20cm>20-40cm>40-60cm. It shows that long-term reclamation after homestead remediation is beneficial to the increase and fixation of surface soil organic carbon.
Technology Research of Desulfurization Wastewater Zero Emissions
Authors: Xue Fangming , Chen Feng , Sun Yiqing , Liu Xiuru , Su Jingcheng
Published: August 2019

This paper investigates the operation process and operating costs of Heyuan Power Plant and Hengyi Power Plant wastewater by on-site inspection. It is considered that in areas with high environmental protection requirements, the highly reliable pretreatment + evaporation crystallization process should be considered first. In combination with the situation of the power plant, a reverse osmosis system is added after the pretreatment device to increase the processing capacity of the equipment and reduce the running cost.
Research on the Selection and Application of Aquatic Plants in Constructed Wetlands -- Taking Qinyuan Artificial Lake of Guangxi Polytechnic of Construction as an Example
Authors: Qin Ruqiong
Published: August 2019

The direct absorption of aquatic plants in artificial lake, adsorption of pollutants, indirect improvement of artificial lake environment and promote microbial water purification and other environmental protection effects are increasingly obvious. Taking Qinyuan artificial lake of Guangxi Polytechnic of Construction as an example, this paper selects aquatic plants suitable for local environment with strong decontamination ability, good landscape effect and high economic value in the constructed artificial lake wetland system, which plays an important role in purifying sewage in the campus and the overall environment and achieves the expected purpose. Through this case study, the role of aquatic plants in artificial lake in sewage purification and wetland landscape construction was studied, so as to provide theoretical basis for the application of aquatic plants in artificial wetland in water purification.
Index Weight Determination for Road Tunnel Fire Risk Assessment Based on Fuzzy Analytic Hierarchy Process
Authors: Qin Yueping , Kang Na
Published: August 2019

Road tunnel, as an underground engineering, is characterized by unpredictability which has high fire risks in operation process. In recent years, major fire accidents have happened around the world in road tunnel operation process, causing enormous casualties and economic losses. Therefore, it is very necessary to assess fire risks during the road tunnel operation process. In this paper, an index system of road tunnel fire risk assessment with different categories of assessment indexes is established. Index weight is introduced to show the importance of each assessment index for assessment object. This paper adopts fuzzy analytic hierarchy process (FAHP) to express index weight with qualitative description language through pairwise comparison. Qualitative description language given by experts are indicated by correlative triangular membership function. Finally, through defuzzification and normalization, triangular fuzzy numbers are converted into final weights to establish the fire risk assessment index system during the road tunnel operation process.
Study on ammonia injection and mixed element of SCR denitrification system
Authors: Sun Yiqing , Liu Xiuru , Xue Fangming , Su Jingcheng , Chen Feng
Published: August 2019

Selectivce Catalytic Reduction (SCR) denitrification is the most widely used flue gas denitrification technology for coal-fired power plants due to its excellent comprehensive performance. The key to the denitrification efficiency is the uniform mixing of the reducing agents NH3 and NOX in the flue gas. In this paper, the linear controlled ammonia injection grid, partition-controlled ammonia injection grid and mixed element of type ammonia injection grid are compared. The advantages and disadvantages of various gas flow field uniformity adjustment techniques are analysed. It is pointed out that the mixed element of type ammonia injection grid technology is the main direction of the current ammonia injection technology development. Finally, the future development trend of the ammonia injection mixing device is pointed out.
Common Air Pollutants and Their Prevention in Digital Archives
Authors: Li Xiaoxiang , Yin Xianhao , Gu Tiantian
Published: August 2019

The long-term preservation and utilization of archives make them vulnerable to harmful substances, reducing the storage and service life of archives. Meanwhile, these harmful substances are released into the air, which poses a threat to the health and safety of archivists. This paper analyzes the common air pollutants in the digital archives and proposes some solutions.
Evaluation of Sustainable Development of Eco-environment in Tianjin
Authors: Hu Biao , Zhang Jinhui
Published: August 2019

On the basis of discussing the relationship between urban ecosystem and sustainable development, the evaluation index system of sustainable development of human settlements environment in Tianjin was constructed from four aspects: social development level, economic development level, natural development level and sustainability level. The evaluation index of Tianjin ecosystem and its sustainable development level in recent 10 years were calculated by simple arithmetic average method. The relationship between sustainable development of ecosystem and economic development in Tianjin was quantitatively evaluated. The results show that the ecosystem of Tianjin is developing in a sustainable direction, basically in line with the stage of economic development, but there are still some shortcomings which need to be improved urgently.
Preparation and photo-degradation performance of composite catalysts
Authors: Wan Lijuan
Published: August 2019

Through facile mixing and heating method, g-C3N4 and ZnO organic – inorganic composite with varying the content of g-C3N4 has been synthesized. The composite catalysts were characterized by X-ray diffraction, BET surface area measurements and etc. The activity of composite photocatalyst g-C3N4–ZnO with 50% or 70% g-C3N4 for photo-degradation of MO is higher than that of either single-phase g-C3N4 or ZnO under visible light irradiation. Due to the enhancement of electron–hole separation, the as-prepared organic-inorganic composite exhibits an improved photo-degradation performance.
Analysis of Environmental Technology Efficiency of the China on Logistics Industry Considering Resource and Environment Constraints
Authors: Fan Duoduo , Yuan Qingmin
Published: August 2019

In recent years, the logistics industry of China has developed rapidly, and its productivity has shown a rising trend. Considering the resource and environment constraints, China’s logistics industry environmental technology efficiency is also one of the research topics of Chinese scholars. Experts and scholars discuss the environmental technology efficiency of China’s logistics industry from different angles, and effectively protect the environmental protection of the logistics industry of China. In order to promote the logistics industry economy and the vigorous development of resources and environment, this paper will be based on the analysis of the environmental technology efficiency of China’s logistics industry, which is constrained by resources and environment, and provide effective reference suggestions.
Analysis of the correlation between ecology and economy in Dianchi Lake Basin
Authors: Li Dan , Li Yuebo
Published: August 2019

Whether the ecological environment of Dianchi Lake Basin can run well or not is directly related to the smooth implementation of the sustainable development of Kunming City and even Yunnan Province. Without a benign ecosystem in the Dianchi Basin, there would be no rapid socio-economic development in Kunming. This paper analyses the relationship between social and economic development and ecological environment in Dianchi Lake Basin, and explores the relationship between them, which will be helpful to the theory and practice of economic development and ecological construction in Dianchi Lake Basin.
Analysis of Impacts of Extreme Precipitation in Kaizhou on Wanzhou-Dazhou Expressway Transportation
Authors: Liu Shouwen , Han Shigang , Xu Yanping , Li Zhen
Published: August 2019

Based on the rainfall data of Kaizhou, the characteristics of extreme precipitation in Kaizhou from 1960 to 2016 and its influence on transportation are analyzed. The results show that, the number of rainy days was noticeably large before 1980s in Kaizhou, and the number of rainy days was more than 200d from 1973 to 1979. However, the number of rainy days decreased rapidly and basically kept stabile below 150d after 1980s. The threshold value of extreme precipitation events is 20mm in Kaizhou, and the annual average value of extreme precipitation events is 18d. The western Pacific subtropical high pressure extended westward in 2006, and inclined to the west and north, compared with the previous years. Besides, it was stable and maintained for a long time. These gave rise to severe drought in Chongqing in 2006 and further resulted in the decrease of extreme precipitation events in Kaizhou in 2006. There are 3 dangerous areas where weather influencing factor is extreme precipitation in Kaizhou section of Wanzhou-Dazhou Expressway, and they are located at S002 K9+593-K20, S002 K0-K9+593, and S002 K20-K30. Kaizhou section of Wanzhou-Dazhou expressway suffered 7 road closure controls due to extreme precipitation from 2011 to 2014. In 2014, 4 road closures were caused due to frequent extreme precipitation. Strengthening the forecast of extreme precipitation events can reduce occurrence frequency of traffic accidents and give play to the maximum effect of road transportation.
Heavy metal pollution and spatial distribution in Surface Water and Sediment of Nanchang Section of Ganjiang River
Authors: Shi Xianluo , Zhang Wei
Published: August 2019

In order to reveal the spatial distribution and pollution characteristics of heavy metals in surface water and sediment of Nanchang section of GanJiang River in JiangXi Province, potential ecological hazard index method and ground accumulation index method were used to evaluate the risk of heavy metals. The results show that: 1) The concentration of heavy metals in surface water of GanJiang River is much lower than the first standard limit of “Surface Water Environmental Quality Standard GB3838-2002”. 2) The average RI value of sediment in Nanchang section of GanJiang River is 144.21, and the total ecological risk level is very high. The RI of two sections of Bayi Bridge are 169.89 and 192.38, respectively, which have become potential ecological high-risk areas. 3) According to the method of accumulative index, the pollution degree of heavy metals in GanJiang River is as follows: Cu > Cd > Pb > As > Cr > Zn. Among them, Cu and Cd are the main pollutants. Relevant departments should take urgent measures to strengthen the environmental management and pollution control of GanJiang River.
Analysis of Safety Factors of Urban Sewage Treatment Plant Based on AHP Method
Authors: Xia Liming , Feng Xiaowei
Published: August 2019

In the process of social and economic development, the process of urbanization is also accelerating. Environmental engineering has become an important task to ensure the urban environment and the quality of people’s living and living, and is also a key link to achieve urban layout optimization. Due to the late start of environmental engineering in China, there are still many problems to be solved. Based on China’s actual national conditions, this paper classifies the identified security risks and builds a safety evaluation index system for urban sewage treatment plants. Finally, the analytic hierarchy process is used to construct the importance model of security risk factors, and the importance ranking of the main security risk factors is obtained.
Numerical Simulation of Pollutants Emitted from Diesel Engine Combustion
Authors: Li Yong
Published: August 2019

Based on the control research of diesel engine combustion emission pollutants, a reasonable numerical simulation study is carried out. At present, hydrocarbon fuel is a common fuel in transportation. Its combustion quality directly affects emissions. Reducing sulfur content and polycyclic aromatic hydrocarbons content in diesel can effectively reduce particulate matter emissions. Because of the poor atomization of diesel fuel, diesel in cylinder cannot be completely burned, resulting in the formation of soot, and diesel additives can increase the degree of combustion completion, and then optimize to achieve the effect of reducing soot. Therefore, the numerical simulation of pollutants is carried out and effective measures are taken to control combustion. The combustion model chosen here is Vortex Cluster Fragmentation Model 20, which is based on turbulent mixing rate.
Research on the Greenhouse Gases Emission Reduction of Pig-breeding Industry in China
Authors: Hu Zhongying
Published: August 2019

Pig-breeding process can emit a lot of CH4, N2O and CO2. The contribution rate of pig-breeding in greenhouse gases emission stands first on the list of all livestock breeds in China. The paper gave the way to reduce carbon emission in pig-breeding industry by the respective of environmental techniques.The results showed that we should use the three biogas products and provide households the chances of taking part in clean development mechanism to promote the scientific treatment of pig waste and to reduce emission finally.
Environmental and resource recovery efficiency assessment of the obsolete mobile phones recycling system
Authors: Xue Nannan
Published: August 2019

Considering environmental protection and resource recovery efficiency, the building of low pollution and high efficiency for recycling system of obsolete mobile phones has been a huge issue. Through system dynamics, the recycling model of obsolete mobile phone is built, which involving the recycling effect under different recycling situations between formal and informal recyclers. The vensim PLE software is used to simulate and assess influence variables in the model. The results show that the formal recycling system can improve the efficiency of recovery and reuse or recycling of obsolete mobile phones.
Analysis of Turbulent Characteristics of Sheared Convective Boundary Layer under Different Shear and Potential Temperature Gradients
Authors: Li Anran , Lin Wenxian , Gao Wenfeng , Liu Tao , Xia Yaowen
Published: August 2019

Effects of shear and potential temperature gradient on the formation mechanism and turbulence characteristics of the sheared convective boundary layer are studied through Large-Eddy Simulation (LES) experiments. Four cases with different velocity difference ΔU of 1.5ms−1 and 3.0ms−1 and different potential temperature gradient Γθ of 0.006Km−1 and 0.015Km−1 were conducted in the horizontal homogeneous atmospheric convective boundary layer of 6000m × 6000m × 2000m. The results show that the formation of the entrainment layer is affected integratedly by the horizontal shear effect and the vertical buoyancy effect, in which turbulence shows strong anisotropy and intermittent characteristics, wherein the mixed layer is dominated by stable small eddies, and the entrainment layer by strip-shaped large eddies. Compared with the pure buoyancy boundary layer, the entrainment flux ratio A

f
is 0.176∼0.385, and the height of the entrainment layer z

i
is shifted to the side with bigger velocity (U
2). ΔU promotes entrainment and Γθ inhibits, especially for the upper limit of the entrainment layer h
2. Obviously, the shear-shelter entrainment phenomenon appears under the weak shear and strong potential temperature gradient.
Research of PM2.5 Prediction System Based on CNNs-GRU in Wuxi Urban Area
Authors: Xie Haofei , Ji Lin , Wang Quan , Jia Zhejian
Published: August 2019

Aiming at the serious pollution situation and lack of effective prediction methods in Wuxi urban area, based on convolutional neural network (CNN) and gated recurrent unit (GRU), this paper proposes a PM2.5 prediction model that can automatically extract spatiotemporal features of multi-station and multimodal air quality data, and build a PM2.5 prediction system based on this model as well. The system model firstly takes multiple two-dimensional (2D) matrices constructed with time series of the air quality factors and weather factors from different monitoring stations in Wuxi urban area as input, automatically extracts and fuses the local variation trends and spatial correlation features of multi-station and multimodal data with CNNs structure. The results from the CNNs are input to the GRU network to further capture the long-term dependence feature of air quality data. Then, a fully connected network taking the spatiotemporal features as input is used to predict the PM2.5 concentration for the next 6 hours in Wuxi urban area. The PM2.5 prediction system based on CNNs-GRU model is tested on the real data set provided by Wuxi Environmental Protection Bureau. On the two test sets in January and June, the prediction accuracy of the PM2.5 prediction system reached 76.902% and 70.053% respectively, which is better than the comparative models. Finally, the prediction system based on the optimal CNNs-GRU model and real-time data obtained by crawlers, predicts the real-time PM2.5 concentration for the next 6 hours, and visualizes the prediction results on the Web through Echarts technology. It can provide valuable reference for citizens’ travel, prevention and control of air pollution in Wuxi urban area.
Research of Air Pollutant Concentration Forecasting Based on Deep Learning Algorithms
Authors: Pan YongMing , Wang YaJie , Lai MingZhao
Published: August 2019

In order to accurately predict the concentration of air pollutants in Shanghai, a prediction model of the concentration of air pollutants in Shanghai based on Wavelet Transform and Long Short-Term Memory (LSTM) was established to predict the concentration of six air pollutants in Shanghai. Firstly, the historical time series of daily air pollutant concentration is decomposed into different frequencies by wavelet decomposition transform and recombined into a set of high-dimensional training data. Secondly, LSTM prediction model is trained with high-dimensional data sets, and parameters are adjusted repeatedly to obtain the optimal prediction model. The results show that the combined model is more accurate than the traditional LSTM model in predicting pollutant concentration.