bluuebunny/crossref_metadata_2025_split huggingface dataset:
A three-dimensional non-hydrostatic mathematical model with mixed triangle and quadrilateral grids
Authors: Yu G N , Lv B , Xing Y 
Published: January 2021

Abstract
The three-dimensional numerical models based on the hydrostatic pressure hypothesis can’t accurately and effectively simulate the cases of estuaries or natural rivers with the presence of short wave flow, stratified gravity flow, sudden change of local topography or flow near underwater buildings. Therefore it is useful to resort to a more accurate model in which the hydrostatic assumption is removed. Based on the mixed grids of triangle and quadrilateral, a three-dimensional non hydrostatic mathematical model is presented. The control equations are discretized by the semi-implicit fractional step method. The pressure is divided into the hydrostatic pressure and non-hydrostatic pressure terms. At each step, the water level is calculated by solving the sparse equations, and then the non-hydrostatic pressure is obtained by the pressure Poisson equation. Three typical examples were adopted to simulate strong three-dimensional flow. As a result, the results show that the model can accurately and effectively simulate strong three-dimensional flow with a few layers.
Research of the influence of the excavating and automotive equipment complexes parameters on the speed of faces advance
Authors: Kuznetsov D V , Kosolapov A I 
Published: January 2021

Abstract
The article presents the results of the research on the equipment complexes parameters impact assessment with electric and hydraulic excavators and dump trucks on deposits development intensity. The classification of deposits according to the relative difficulty of development is introduced. For the open pits of each of the identified five classes, the possible speed of faces advance is determined with the diversity of equipment parameters, deposits parameters and panel blocks.
Discussion on the Issues of Rotor-Stator Interference in Pump Turbine
Authors: Xu Hongquan , Gui Zhonghua , Li Tieyou , Liao Cuilin , Meng Long , Zhao Lice 
Published: January 2021

Abstract
There are serious vibration issues of powerhouse in some pumped storage power plants and it affects severely the safe and stable operation of power plant. In order to settle the issues which have troubled the hydropower technology for several decades, extensive researches have been made. The rotor-stationary interference between rotating runner and stationary guide vanes are one of the researched issues concerned most and has the biggest influences. In this paper, the different opinions are presented. Firstly, the characteristics of pressure variations before and after the guide vanes are discussed and it indicates that, the pressure distribution is not uniform due to the turbulent flow around guide vanes but there is no pressure fluctuation with the dominant frequency of rotational frequency multiplying guide vane number. The interference precondition of pressure waves is there are two pressure waves with the same frequency, thus the new opinion, there is no rotor-stationary interference in the vaneless area, is presented. Secondly, equations of rotor-stationary interference presented by Hiroshi Tanaka and its derivation process are introduced. The equation foundation, physical meanings of parameters and equation dimensions are analyzed, and it is concluded that it is wrong to combine the pressure waves from rotating part and stationary part by multiplying the two pressure waves. And also the following mistakes and unreasonable issues are described. The studied objects are not consistent with that in practical application, the pump condition is not considered, the steady operation is taken as unsteady, and the definition of nodes is mistaken. The correct combination method of rotor-stationary interaction are presented.
Effects of Impeller Trimming on Performance in a Double-suction Centrifugal Pump
Authors: Deng Qifan , Pei Ji , Wang Wenjie , Yuan Shouqi 
Published: January 2021

Abstract
In order to research the relationship between impeller trimming and performance in a double-suction centrifugal pump, impellers were trimmed 11mm and 22mm respectively. Numerical methods were applied combined with the original one, and experimental validation was also carried out on original and 11mm model. The performance and difference of total pressure between volute inlet and outlet was calculated, meanwhile, distributions of velocity and turbulence eddy dissipation on volute middle section were analyzed. The results indicate that the head drops with the trimming process and discontinuity appears when trimmed 22mm. The impeller trimmed 11mm is the most efficient under part-load and design conditions, while the original model has the lowest efficiency. Efficiency in trimmed cases decreases dramatically under over-load condition, especially when trimmed 22mm. Duo to rotor-stator interaction between impeller and volute receded by the enlarged clearance, the head losses inside the volute decrease with impeller trimming but increase significantly under 1.4Qd when trimmed 22mm. The extremely high shock losses resulting from exaggerated impeller outlet flow angle and dissipation near volute tongue account for it. Moreover, the losses in volute diffuser channel increase due to the vortexes generated by flow separation and backflow. The losses in volute will be improved by impeller trimming within reasonable limits in a double-suction pump. This research provides theoretical foundation for impeller trimming in double-suction centrifugal pumps.
Optimization for First Stage of Multistage Pump Based on Response Surface Methodology
Authors: Jiang Wei , Pei Ji , Wang Wenjie , Yuan Shouqi 
Published: January 2021

Abstract
To improve the efficiency of a multistage centrifugal pump at design point, the response surface methodology was applied to construct an approximation function between the design-point efficiency of the first stage in multistage centrifugal pump and the design variables of the impeller. First, important geometric parameters are selected as factors of a one-factor experimental design. Four parameters that had greater influence on the hydraulic efficiency were screened out from the simulation results using parameter sensitivity analysis. The optimal design points for each level of the parameters were then determined by central composite design and the response surface analysis method. The efficiencies of the impeller schemes generated in the Design-Expert software was executed with CFD. The effects of the single parameters were analysed, and the approximation model solved to find the optimal parameter combination that improve the efficiency by 3.62% at design point. And the inner flow was improved in high flow rate condition.
Experience Measurement of Winter-Kennedy method on low head tubular turbine units
Authors: Zhou X Z , Wang Z W , Ahn S H , Xia M , Yi Z C 
Published: January 2021

Abstract
With large development of renewable energy, especially the low head hydraulic power stations, specifications of the turbines have been got more and more attentions. The discharge, which is one of the most important parameters relative to unit performances, is difficult to be determined according to the passage layout. In this paper, applying “Winter-Kennedy” measurement method though modification and comparison with test and simulation, characteristics and coefficients of turbine units, derived from different pressure at certain locations, are calibrated and established. After further verification, it will of great help to confirm the relationship of unit output, water head and hydraulic efficiency, as well as optimal dispatching and stable operation of hydropower stations.
Fatigue Life Prediction of a Pump Turbine Runner
Authors: He Q L , Liu T , Yang X L , Chen F N , Wang C , Liu J S , Wang Z W 
Published: January 2021

Abstract
The working environment of the runner of a hydro-turbine unit is complex, and it is subjected to relatively large and variable water pressure. Fatigue cracks may occur after a long period of work, and even cause the runner to lose its working ability. The fatigue crack problem of hydraulic turbines should be paid attention to. This paper introduces the nominal stress method which is often used to analyse the fatigue life of a hydraulic turbine unit. Modelling and numerical calculation are carried out for a pump turbine unit. Stress concentration points and load spectra are calculated for different working conditions of the turbine. The load spectra are processed by rain flow counting method. The fatigue life of the runner under different working conditions is carried out by Miner criterion. The results show that the fatigue life of the unit tends to be infinite under steady working conditions, and the fatigue life under variable working conditions is far less than that under steady working conditions. Therefore, from the point of view of fatigue life, the working process under variable working conditions should be minimized to improve the service life of the unit.
Research on Unsteady Characteristics of Pump Turbine in Pumping Mode
Authors: Liu Yong , Ran Hongjuan , Wang Dezhong 
Published: January 2021

Abstract
A study on the unsteady characteristics of pump turbine in pumping mode was made. Basing on the existing research, this paper is aimed at providing valuable reference for hydraulic design, structure optimization, fault diagnosis of pump turbine. CFX simulation verified by experiment was made to analyze the distribution law and propagation characteristic of pressure and its pulsation in the whole fluid field. Research shows that the pressure pulsation owns different propagation characteristic from the flow velocity pulsation. The pressure pulsation component with guide blade frequency has very special properties in stationary flow passages, while the pressure pulsation component with runner blade passing frequency is absolutely different. Blade constraints have significant effect on the unsteady properties of pressure and flow velocity. Besides, some other analysis was talked about, such as the external characteristics, pressure pulsation near the volute tongue, and so on.
Coupling Spatial Distribution and Industrial Structure Optimization Analysis of Economic and Environmental Pollution in Chongqing
Authors: Gou Xiaomeng , Li Yao 
Published: January 2021

Abstract
In recent years, as one of the old industrial bases in China, although it has been promoting the construction of new industrialization, Chongqing is still facing a more severe situation of industrial pollution. In order to further upgrade the optimization of industrial structure in Chongqing, the paper combined with 2773 cases of Chongqing pollution administrative penalties. Select industrial pollution enterprises administrative penalty amount of the 38 districts and counties in Chongqing as cross-sectional data, the spatial correlation of industrial pollution in Chongqing was analyzed by exploratory spatial analysis. Then, using the coupled coordination degree model, the evaluation index system of economic development and industrial pollution coupling degree in Chongqing area is established, and the spatial pattern of the economic environment coupling degree in Chongqing is analyzed. It is found that the spatial agglomeration characteristics of industrial pollution in Chongqing are not obvious, and the regional pollution is different, the economic environment system is in the state of low coupling, the spatial types of the coupling degree of regional economic environment are the most antagonistic economic environment, and the minority is the low coupling region. Based on the results of spatial layout, this paper analyzes the industrial structure of Chongqing City and put forward the optimization strategy of industrial structure.
Fishery migration under the influence of global warming
Authors: Tang Jian , Zhu Zeqi , Guo Siyi 
Published: January 2021

Abstract
With the pace of global warming getting faster and faster, the temperature of the sea is gradually rising. Meanwhile, Scotland, located on the east coast of the North Atlantic, is facing a serious problem: how to develop their fishing industry while fish are migrating. In this article, we will use a series of models to analyze the current situation and recommend some ways for the development of small Scottish fishing companies. In Task 1, based on the sufficient global ocean temperature data recorded by the Met Office Hadley Centre, we firstly used the convolutional neural network (CNN) model to learn the ocean temperature change in the waters around Scotland in the past 50 years, to find out the changing trend and make a reasonable prediction on the sea temperature (SST) change in the next 50 years. Then, by using the obtained data in ocean temperature, continental shelves, and ocean currents, the behavior of herring and mackerel was excavated and simulated. Besides, we build a double-objective Linear Programming (DLP) model to predict the location of these two fish species in the next 50 years, based on the distribution patterns of the Scottish fisheries over the past 50 years. What’s more, we also performed the Process of Gridding on the map of Scotland, making all the models easier to calculate. In Task 2, we used the Logistic Growth Model (LGM) to establish a freshness model for captured fish, combined with the speed of a Scottish fishery boat to calculate the company's fishing range. Then we obtained the best and worst situations of the two fish habitats for the company's fishing business in the next 50 years through the fine-tuning of the parameters and sensitivity analysis. Also, we predicted the most likely future time for the company to be unable to continue fishing if maintaining a former strategy. In Task 3, we simulated the model in Task 2 to obtain a fish freshness model with refrigeration equipment, which provides basic elements needed for relocating a fishing port or updating fishing boats. Lastly, through the establishment of the Abstract Value-Estimated Model (AVEM), we roughly calculated the value of the two schemes to finally assure that the relocation of the fishing port was more economical. Although we did a lot of research to improve the accuracy of our work, the political decision of the government will change indefinitely, which means that our research still needs some innovational work before the actual adjustments of Scottish fishery.
Metal-Organic Framework as a New Photocatalyst for Environmental Pollutant Treatment
Authors: Ying Chenghao 
Published: January 2021

Abstract
Metal-organic frameworks (MOFs) which are novel and burgeoning porous crystalline materials. In recent researches, MOFs demonstrated a variety of applications due to their unique features: large surface area and tunable porosity. The unique features have attracted extensive researching interests in exploring the application of MOFs as photocatalysts for environmental remediation. Herein, the review starts with an overview of fundamental aspects of MOFs followed by the introduction of several synthesizing techniques. The discussion of MOFs characteristics and their applications in photocatalysis will be focused on.
Research progress of semiconductor photocatalysis applied to environmental governance
Authors: Zhao Zhiio 
Published: January 2021

Abstract
A review of the current research situation of semiconductor photocatalysis at home and abroad, and a brief analysis of the existing problems and future development trends. Listed some of the achievements of photocatalysis research in the past 30 years, covering the research of photocatalysis mechanism, the application research of photocatalysis technology in the environmental field, and the contemporary problems of photocatalysis technology, etc. from basic to applied research.
The Determination of Nitrite Content in Market Sausages
Authors: Yuan Lei , Zhang Jingyu , Wu Xiao , Li Na , Liu Haiyan , He Lijie 
Published: January 2021

Abstract
As a common food additive, nitrite exists widely in cooked meat foods such as sausages. This paper establishes a simple, sensitive and more accurate spectrophotometric method to measure the content of nitrite in sausage foods. After earlier period of treating the samples, the purple-red products formed with naphthyl ethylenediamine hydrochloride under weak acid conditions have the maximum absorption at 540nm. The content of sodium nitrite has a good linear relationship in the range of 0∼0.40μg/mL by experimental analysis. The linear equation is A=0.6496C+0.0029. The correlation coefficient R2=0.9969. The recoveries were in the range from 100.1% to 104.7%. The results of detecting the samples show that the nitrite content of the samples is between 2.8920 and 10.9498 mg/kg, which corresponds to the national limited standard.
Determination of Benzopyrene in edible fish
Authors: Zhang Jingyu , Yuan Lei , Zhang Lin , Pan Yi , Chen Hong , Jiao Jifeng 
Published: January 2021

Abstract
Benzopyrene is a kind of polycyclic aromatic hydrocarbons and a strong carcinogen. Now, more attention has been paid to benzopyran pollution in food. In this paper, taking the edible fish in Yingkou area as the representative, the extraction solution was determined by UV-Vis spectrophotometer. The results showed that the content of benzopyrene in the three kinds of edible fish was less than the national standard among them, the benzopyrene content of sea catfish is high, and then the risk of carcinogenesis and pollution are analyzed, the results are within the safe range.
Analysis of Electronic Equipment Recycling Based on Environmental Economic Background
Authors: Chen Yuanyuan 
Published: January 2021

Abstract
Since the reform and opening up, China's economy has achieved rapid and stable growth, especially the rapid development of the electronic industry. However, these electronic products contain many harmful chemicals. If not properly handled, they will seriously harm the ecological environment and human health. However, many enterprises lack systematic management in the process of developing logistics, and waste a lot of money and energy in logistics, especially in reverse logistics. How to reduce the problems of reverse logistics management is a problem that enterprises need to consider. Under the background of environmental protection economy, this paper studies a set of reasonable electronic product reverse logistics management scheme.
Long-term aging performance study of asphalt with different composition
Authors: Xu Meng , Zhang Yuzhen , Zhao Pinhui 
Published: January 2021

Abstract
Thin film oven tests (TFOT), pressure aging tests (PAV) for 5 h, 10 h, 15 h, 20 h were carried out on asphalts from 6 crude oil resources. Conventional and dynamic shear rheological tests (DSR) were carried out on samples at different aging degrees, respectively to evaluate the aging performance of asphalt with different composition. The main conclusions are as follows: asphalt composition had obvious influence on the long-term aging performance, in which the asphaltene content of asphalt is negatively correlated with the long-term aging performance of asphalt. According to experimental results of aging process influence on storage modulus G', A3, A5 and A6 asphalts had worse anti-aging performance than A1, A2 and A4. Meanwhile based on test results of aging process influence on loss modulus G", A1, A2 and A4 asphalts had worse anti-aging performance than A3, A5 and A6 asphalt.
Experimental study on uniaxial compression after creep characteristics of similar soft rock containing cross cracks
Authors: Cui Lizhuang , Ge Qiang , Zhou Tongtong , Liu Yaqi , Wang Yongyan 
Published: January 2021

Abstract
In order to study the creep phenomenon and failure law of rock materials containing cracks, uniaxial compression test and uniaxial compression test after creep are carried out on similar soft rock samples containing different angles of cross cracks, and the differences of rock mechanical properties after two tests are compared and analyzed. Results show that creep effect increases the compactness of the internal structure of the sample, the elastic modulus improve, enhance the ability of resistance to elastic deformation, the peak strength increases, and 15° cross crack sample is more seriously damaged, 30°, 45° and 60° cross crack samples generate deeper and longer crack propagation and broken degree is lower, 75° and cross sample produce fewer cracks.
Research on centralized cooling system of coal mine based on fuzzy hierarchical method
Authors: Zhao Juan , Li Yuanzhen 
Published: January 2021

Abstract
The problem of heat damage in coal mines is becoming more and more serious, and the implementation effect of cooling system has become a matter of concern. In order to objectively evaluate the implementation effect of the mine cooling system, a comprehensive evaluation index system of the mine cooling system is established, and each index is quantified by expert scoring. Applying the combination of AHP and fuzzy comprehensive evaluation to comprehensively evaluate the cooling effect of the specific working face of coal mine, and propose management suggestions based on the evaluation results. The results of calculation and analysis show that the evaluation result of a coal mine cooling system is "good", which meets the requirements of mine safety in production.
Influence of Bifurcation Pipe Position on Hydraulic Turbulence for Pumped Storage Power Station
Authors: Cao Linning , Li Zhaowen , Li Yong , Li Bing 
Published: January 2021

Abstract
There must be hydraulic turbulence transient in the pumped storage power station with one pipe corresponding to several units. This paper established a simulation model by using the method of characteristics for a pumped storage power station to analyse how the change of upstream and downstream bifurcation pipe position and different arrangements of downstream surge tank affect the hydraulic turbulence. The results indicate that unit output’s amplitude of power mode is smaller than that of frequency mode. And the upstream and downstream bifurcated pipes far away from the units can reduce the hydraulic turbulence of normal operating unit while the upstream without bifurcation pipe is better than the downstream without bifurcation pipe to control the output swing. Sharing the downstream surge tank can effectively reduce the maximum relative over output of the unit, while the surge tank placed in the downstream branch pipe will worsen turbulence process.
The Discussion on Hot Spot and Frontier of Energy Research in Smart Cities
Authors: Tang Jun 
Published: January 2021

Abstract
Taking the journal documents published between 2008 and 2019 in the core collection of web of science as samples, using citespace software, a visual analysis of the research literature in the energy field in smart cities from the three dimensions of research evolution path, research hotspot, and research frontier. The results show that smart city energy research has gone through three stages: the initial exploration of theoretical concepts, the growth period of technology application, and the coordinated industrial development period. The research hotspots mainly focus on the demand research of energy construction in smart cities, the research of energy intelligent construction and the energy of smart cities Construct three aspects of related industry research; the frontiers of research mainly include energy internet, smart energy and big data.