bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of population agglomeration on air pollution: An empirical study based on the mediating effect model
Authors: Yang Bin , Ding Lijin , Tian Yihao 
Published: March 2021

Abstract
With rapid urbanization and industrialization, the population of metropolis in China is increasing. Previous studies suggest that population agglomeration would have a significant impact on air pollution in cities. Using a panel dataset of 30 provincial capital cities during 2013-2017, as well as days of air quality equal to or above Grade II as air pollution indicators, the results show that an increase of population density will improve air quality in large cities. Through the mediation effect test, this paper found that tertiary industry is the mediation channel of population agglomeration to reduce air pollution. An increase of population density in big cities is conductive to increasing the proportion of tertiary industry, thereby reducing the proportion of seriously polluting secondary industry, and reducing air pollution.
Study on Temporal and Spatial Distribution of Biogenic Elements of Sediment in Baiyangdian Lake
Authors: Zhen Han , Xiaobo Liu , Shiyan Wang , Pengfei Yu 
Published: March 2021

Abstract
Baiyangdian Lake is the largest macrophyte-dominated shallow lake in North China and the most important ecological barrier area in the Xiong’an New Area. Since the 1980s, the surface water of Baiyangdian Lake has been in a state of eutrophication for a long time due to high nitrogen and phosphorus content. Under the background of the gradual implementation of the New Area Planning Outline, the load of nitrogen and phosphorus from exogenous sources into the lake has been gradually controlled, and the nitrogen and phosphorus enriched in the sediment has increasingly become the main factor affecting water quality. Therefore, this study focused on the vertical and lateral distribution differences of total organic carbon, total nitrogen and total phosphorus contents in Baiyangdian Lake sediments. Meanwhile, combined with sedimentary years, the enrichment characteristics of nitrogen and phosphorus in different ages and their consistency with the change of total organic carbon content were analyzed. The study can provide some scientific reference for controlling the accumulation of nitrogen and phosphorus in Baiyangdian sediment and scientifically and orderly dredging.
Classification and prediction of wear state based on unsupervised learning of online monitoring data of lubricating oil
Authors: Su Yongsheng , Li Dayang , Wang Heng , He Chen , Yang Kun 
Published: March 2021

Abstract
With the development of the times, the demand for high efficiency and reliability of machine performance in China’s industry has become higher than ever before, and the traditional equipment condition evaluation method has also encountered a huge challenge. As an important branch of machine learning, cluster analysis is widely used in fault diagnosis and other fields because of its advantages of no prior knowledge and massive data processing. This paper introduces the concept of principal component analysis and K-means method based on time series in the field of oil data analysis. Through the test data on the oil monitoring data of the steam turbine unit in the power plant, the condition evaluation and classification of the equipment are carried out, among which the classification effect of 6μm particles, dielectric constant and 4μm particles is very obvious, and the water content is relatively obvious, which can basically distinguish each state. At the same time, on the basis of feature extraction, use the special cyclic neural network (RNN) in deep learning-long and short-term memory network (LSTM) to build a model of data for data prediction, under the powerful ability of LSTM to process temporal data, they have unearthed more irregular and non-linear trends in a large amount of historical data, and achieved better prediction results than traditional methods (ARIMA). Through clustering and prediction of lubrication parameter data, it can realize early warning and abnormal diagnosis of lubrication status and reduce damage to machinery and equipment.
Research on the Impact of Policy Transmission on Pollution Control of Livestock Breeding
Authors: Yu Wensong , Cai Xiaoshen , Wang Shujun 
Published: March 2021

Abstract
Scientific policy transmission is the key for local governments to effectively control pollution from livestock breeding. This study collects the livestock manure treatment policy texts and livestock feeding data of 70 local governments, and uses data mining and related analysis methods to analyze the relationships between actions, actors and the effect of livestock breeding pollution control in local government policies. The results show that: the better the transmission of actions and the greater the number of actors involved in transmission of actions, the better effect of livestock breeding pollution control. It is necessary to strengthen collaboration with Department of Natural Resources in building a cycle of planting and breeding development mechanism as well as acceleration of the transformation and upgrading of animal husbandry. Meanwhile, the collaboration with Department of Science and Technology should be enhanced in strengthening fiscal and taxation policy support, and coordinating the solution of land and electricity use problems.
Dynamic Migration theory, put forward by Dongfang Yang, of Cd content in Jiaozhou Bay
Authors: Yang Dongfang , Li Haixia , Zhang Longlei , Wang Qi , Ling Weifeng 
Published: March 2021

Abstract
Based on the horizontal and vertical matter content changing models proposed by the author himself, this article calculates the horizontal loss amount, vertical disputed amount and vertical sediment amount, and determines the block diagram of horizontal and vertical Cd content changing model, applying the investigation matters about the Cd content of Jiaozhou Bay in May, August, and October, 1992. According to the calculation results of horizontal loss amount and horizontal increase amount of Cd content in the bottom layer and the vertical disputed amount and vertical sediment amount of Cd content in the surface and bottom layer, the author proposes the dynamic migration process of Cd content in Jiaozhou Bay, pinpoint the migration direction and route of Cd content from southeast waters to the center waters of the bay in May, August and October: sources→surface layer of southeast water→bottom layer of southeast water→bottom layer of center water→surface layer of center water, and get the dynamic changing process of absolute and relative migration amount of Cd content.
Evaluation of chloride diffusion in concrete using PSO-BP and BP neural network
Authors: Yao Ling , Ren Lixia , Gong Guoli 
Published: March 2021

Abstract
Chloride diffusion is the major causes of deterioration of concrete structures in engineering. Because chloride diffusion experiments are time consuming, it is desired to develop a model to predict the chloride diffusion in concrete. In this paper, the optimizing of particle swarm algorithm (PSO) on BP neural network is adopted to predict the chloride penetration in concrete. For purpose of building these models, training and testing pattern is gathered from the technical literature. PSO-BP neural network can improve BP disadvantage. PSO-BP neural network is better precision than BP neural network through the results of PSO-BP, BP and experiments. The research results demonstrate that PSO-BP neural network is an effective tool in the prediction of chloride diffusion.
Study on Soil Moisture Temporal-Spatial Variation and Stability in Loess Plateau of China
Authors: Wang Yanpeng , Zhou Ying , Liu Xueyong 
Published: March 2021

Abstract
Soil moisture temporal-spatial distribution and stability are important factors influencing soil pollutant transport, material migration, regional climate change, hydro-ecological environment as well as agricultural production patterns. According to soil moisture distribution features on the loess plateau, the paper selected three different kinds of surface slopes on the typical experiment sites to carry out soil moisture measurement. The variation coefficient and rank correlation method are proposed to calculate the longitudinal and vertical soil moisture distribution characteristics. The temporal-spatial dynamic features of soil moisture are studied. The present findings show that the soil moisture in the Loess Plateau varies greatly at different soil depths during the period from April to June. The maximum soil moisture appears at the depth of 40-60 cm. The variation coefficient of soil moisture increases with the soil depth. It was discovered that there exists temporal stability at the depth of 20-80cm. The correlation coefficient of soil moisture in different slopes is significant during the period of April-June. The results would play an important support in theoretical research and ecological environment planning, optimization of agricultural planting pattern and comprehensive management of Loess Plateau.
Preparation of nanoscale zero-valent iron and its application in coking wastewater treatment
Authors: Wu Shihong , Yu Le , Li Meiling 
Published: March 2021

Abstract
Nanoscale zero-valent iron (NZVI) was prepared by liquid phase chemical reduction method. The nanoparticles were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of prepared three nanoscale materials was evaluated by degrading coking wastewater. Optimal experiments involved the effects of water sample initial pH and Fe/C of NZVI on COD removal efficiencies were also investigated. It indicated that NZVI showed more excellent COD removal efficiencies. Under the optimal condition of dosage 1 g in 300 mL wastewater, Fe/C 1:1, pH 4, 120-min reaction time, the COD removal rate by NZVI could reach 67%.
Research on Human Reliability Model of a Reservoir Dam
Authors: Dandan Li , Ji Wang , Huiwen Wang 
Published: March 2021

Abstract
The safety of reservoirs has a great impact on the social and economic life of the country, and human factors in modern life occupy an increasingly important position. This paper uses the prediction technology of human error probability, establishes the reliability model of human factor cognition based on Bayesian network, quantifies the influencing factors of human factor, and actually uses the calculation in a certain reservoir dam.
Preparation of Autoclaved Aerated Concrete from Construction Waste
Authors: Xia Jiageng , Chen Yongliang , Chen Junbao , Li Aojun , Chen Tiejun 
Published: March 2021

Abstract
This research focuses on the preparation of autoclaved aerated concrete (AAC) with construction waste as the main raw materials. The properties of dry density and compressive strength of AAC were tested to determine the optimum mix proportion of raw materials and the construction waste fineness. The results indicated that the optimum mix proportion of raw materials was consist of 55-65% construction waste, 15-21% cement and 18-22% quicklime, together with 2% gypsum and 0.1% aluminum powder, the construction waste was mechanically milled for 20 min, and cured in the conditions of autoclave pressure 1.5 MPa for 6 h, the compressive strength of AAC samples were higher than 5.0 MPa, and dry density value could reach 650-700 Kg/m3, which meet the requirements of A5.0 B07 grade in the Autoclaved aerated concrete blocks (GB11968-2006). The analysis of microstructure and phase compositions of the AAC samples showed that the tobermorite, calcite and CSH were formed in the process of autoclave curing, and CSH gels were combined through the skeletons formed by tobermorite crystals, the interconnected and porous microstructure contributed to the good properties of low density and high strength of AAC.
Uptake of polystyrene microplastics by marine rotifers under different experimental conditions
Authors: Lan Ruyi , Wei Yongpeng , Xue Runze 
Published: March 2021

Abstract
Marine microplastic pollution has become one of the global problems due to the adverse effects of microplastics on marine organisms. This study investigated the uptake of (Polystyrene, PS) microplastics by marine rotifers (Brachionus plicatilis) under different microplastic concentration, exposure time and type of containers. The results showed that the ingestion of microplastics by rotifers was positively correlated with microplastic concentration. The intake reached maximum (65±5 particles/individuals, 5 mg/L; 28±11 particles/individuals, 3 mg/L) at 24 h, and then decreased over time. Moreover, the intake of microplastics in the plastic well plates was much lower than that in the glass vial. This study demonstrated that the intake of microplastics by rotifers varied with microplastics concentration and exposure time. More importantly, microplastics-related experiments using plastic containers could influence the uptake results. This work provides useful information on the interaction of microplastics with marine organisms.
Preparation of orange peel loaded Zn/Al-HT and its adsorption for Cr(VI) in water
Authors: Zhang Chao , Zhou Xi , Gao Feng 
Published: March 2021

Abstract
The orange peel loaded Zn/Al Hydrotalcite (Zn/Al-HT) was prepared by coprecipitation method. The effects of calcination temperatures, initial concentrations and pH on the adsorption properties of Cr(VI) were investigated, and the results showed that the calcined orange peel loaded Zn/Al-HT at 300°C(Mod2-LDO-300) had best removal rate of Cr(VI), it can be 96%, and the adsorption capacity is 38.5-106.2mg/g in the range of Cr (VI) initial concentration of 20-80mg/L. The Mod2-LDO-300 has a good adsorption effect at pH 2-8. It is a kind of environmental protection and industrial adsorption material.
Experimental Study on The Oxidative Degradation of RO Concentrated Water by Ti/IrO2-RuO2 Electrode
Authors: Wang Tingfeng 
Published: March 2021

Abstract
Advanced treatment and reuse of wastewater is an effective way to solve the shortage of water resources in China. The advantages of RO Technology, such as better water quality and lower operating cost, have become the mainstream desalination technology for wastewater reuse. However, RO technology will produce a certain amount of concentrated water, which contains a large number of inorganic salts and soluble refractory organics. The efficient removal of refractory organics in this high salinity system has become the main bottleneck and problem faced by RO technology. In view of the difficulty of further biochemical treatment of the concentrated water in the RO unit of a sewage treatment plant, the electrochemical method is used to treat the concentrated water. The effects of electrode spacing, current density and reaction time on the treatment of RO concentrated water were discussed. The optimal operation parameters for the treatment of 300ml of the wastewater are as follows: plate spacing 1.5cm, current density 300A/m2, reaction time 20min. Under the above conditions, the COD removal rate can reach 95%, and the lower the initial COD value, the higher the degradation efficiency.
Microwave assisted rapid synthesis of glycerol carbonate from glycerol catalyzed by anhydrous sodium silicate
Authors: Luo Deyi , Xie Mengjiao , Zhou Xi 
Published: March 2021

Abstract
Glycerol carbonate, a value-added derivative of biomass glycerol, has been synthesized by the transesterification of dimethyl carbonate with glycerol using anhydrous sodium silicate (Na2SiO3) as highly efficient, green and available solid base catalyst. The yield of glycerol carbonate reached up to 93% in 10 minutes under microwave irradiation. The result of leaching test indicated Na2SiO3 was a well-defined heterogeneous catalyst for the reaction. In addition, Na2SiO3 could be reused in 4 runs without significant loss of its catalytic activity.
Study on the Compatibility of Carbon / Silicon Carbide Composite Ceramics with Dinitrogen Tetroxide
Authors: Wang Weiqing , Tong Wei , Zhao Bing , Yan Jiujuan , Cong Rimei , Zhang Liqing 
Published: March 2021

Abstract
In this paper, the compatibility of carbon/silicon carbide composite ceramic materials and propellant dinitrogen tetroxide was studied. Referring to similar standards, the test parameters and immersion test scheme were selected. The changes of dinitrogen tetroxide properties and mechanical properties of ceramics before and after the experiment were mainly investigated, which provided theoretical and data basis for the application of this ceramic material in the field of dinitrogen tetroxide.
Dynamic Migration Process of Cd to the Bay Center
Authors: Yang Dongfang , Li Haixia , Zhang Longlei , Wang Qi , Ling Weifeng 
Published: March 2021

Abstract
Based on the horizontal and vertical matter content changing models proposed by the author himself, this article calculates the horizontal loss amount, vertical disputed amount and vertical sediment amount, and determines the block diagram of horizontal and vertical Cd content changing model, applying the investigation matters about the Cd content of Jiaozhou Bay in May, August, and October, 1992. The calculation results show that the variation range of absolutely horizontal loss amount of Cd content in the bottom layer is 0.63-0.82μg/L and the variation range of relatively horizontal loss amount is 68.90-87.50% in May and October. In August, the absolutely horizontal increase amount and relatively horizontal increase amount of Cd content in the bottom layer are 0.94 μg/L and 87.03%, respectively. The Cd content in the surface and bottom layer of southeast waters in August all have the absolutely vertical disputed amount 0.61μg/L and relatively vertical disputed amount 81.33%. The Cd content in the surface and bottom layer of southeast waters in May and October have the absolutely vertical sediment amount within 0.49-0.68μg/L and relatively vertical sediment amount within 57.14-68.05%. In the center of the bay, the Cd content in the surface and bottom layer in August have the absolutely vertical sediment amount 0.96 μg/L and relatively vertical sediment amount 88.88%. In May and October, the absolutely vertical disputed amount and relatively vertical disputed amount of Cd content in the surface and bottom layer of bay center are 0.35-0.52μg/L and 58.42-79.54%, respectively.
Propulsion life prediction based on support vector machine
Authors: Tang Ran , Fang Gang , Liu Guangjia , Wang Heng 
Published: March 2021

Abstract
The advanced technology of the propulsion device is a national key research project, and PHM prediction and health management are among the core technologies. Our prediction of the remaining effective life (RUL) of the propulsion unit is a key part of the PHM technology. The data-driven method can effectively predict RUL. For example, the artificial intelligence method is widely used because it has certain advantages. Therefore, this paper uses machine learning algorithms to carry out RUL prediction research of propulsion devices. In addition, on the basis of support vector machine (SVM) regression theory, we combined the method of SBI (similarity-based interpolation), using Matlab program to build a prediction model. Both the practice samples and test samples of the model come from the engine simulation data, CMAPSS, provided by NASA. Finally, we use test samples to test the prediction model. The results show that the constructed model has good accuracy and robustness, and it can better predict the RUL of the propulsion unit.
Hyperspectral parameters and prediction model of soil moisture in apple orchards
Authors: Wang Wenqian , Gao Mingxiu , Wang Jiafan 
Published: March 2021

Abstract
In this study, the apple orchard of Shuangquan town in mountainous and hilly area of central Shandong Province was taken as the research area. The relationship between the ratio spectral index (RSI), difference spectral index (DI) and normalized difference spectral index (NDSI) and soil moisture content in the range of 400nm-2450nm was explored, and then a quantitative estimation model of soil moisture content was build. The results show that the correlation between soil moisture content and spectral reflectance can be improved by different spectral index calculation. The sensitive modeling areas determined by RSI, DI and NDSI are all near the third water absorption peak, among which RSI (R2304, R2081), RSI (R2306, R2080), RSI (R2306, R2081), RSI (R2307, R2079), RSI (R2307, R2080), RSI (R2307, R2081), RSI (R2308, R2080) and RSI (R2308, R2081) the PLSR regression equation constructed for independent variables has the best estimation effect, the largest determination coefficient (R2 = 0.7918), and the smaller Root Mean Square Error (RMSE = 0.0054). The selection of full band spectral index can better extract effective information, and significantly improve the accuracy and adaptability of soil moisture spectral estimation model.
Damage Detection of Transmission Tower Based on Stochastic Subspace and Statistic Model
Authors: Xingjie Wang , Tingting Yang , Meigen Cao , Chong Zheng , Wensong Zhou , Yutong Pang 
Published: March 2021

Abstract
During the long service period of the transmission tower, the severe environment, material aging and fatigue effects result in the damage accumulation and resistance fading of the transmission tower, which even lead to the structural failure. In this paper, a stochastic subspace-based damage detection algorithm combined with statistical model is proposed for the damage identification of transmission tower structures through processing and analysing its vibration signals. Based on the structural modal parameters identified from the structural vibration response, the nominal modal parameters are defined. Considering that the Hankel matrixes constructed by the system observability matrix and the system output covariance matrix have the same kernel space, the damage index sensitive to the modal parameters is constructed. In the manuscript, firstly, the damage index establishment method and process of the algorithm are presented; and then the vibration data of transmission tower structure simulation under different damage conditions are obtained through numerical simulations; finally, above data are analysed to obtain the damage identification results of transmission tower. The results show that the method proposed in this work can effectively identify the local damage of transmission tower structure.
Numerical Simulation of Natural Gas Hydrate Production with Multiple Fracturing Horizontal Wells
Authors: Tan Bijun , Guo Tiankui , Wang Jia , Yu Tianxi 
Published: March 2021

Abstract
Natural gas hydrate (NGH) has great development prospects as alternative energy source. However, the commercial extraction of hydrate never become reality by conventional depressurization. Hydraulic fracturing assisted depressurization has been proposed to promote gas production. In this work, we presented a 3D multiple fracturing horizontal wells model. Firstly, we compared it with conventional horizontal wells. Then, taking gas production rate and cumulative gas production as performance indexes, the sensitivity analysis of fracturing parameters was conducted. The best fracture parameters for multiple fracturing horizontal wells in this specific hydrate reservoir are the fracture number of 5, the fracture length of 100 m, and the fracture conductivity of 50 μm2·cm, respectively.