bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental research on flow field of high head pump turbine based on PIV test
Authors: Liu D M , Ma L B , Li N , Zhao Y Z , Cheng Huan 
Published: January 2021

Abstract
Pump turbine operating conditions are complex, mainly covering turbine mode and pump mode. Pump turbines have various instability problems during operation, such as S-shaped, pump hump, pressure pulsation and cavitation. PIV (Particle Image Velocimetry) is a very effective test technique for the internal flow field observation of pump turbines. In this paper, the S-shaped, pump hump and pressure pulsation of the pump turbine are tested by PIV technology. The experimental observations show that the internal flow of the pump turbine is extremely complicated. For example, the full quadrant flow characteristics of the S-shaped working condition are observed. It is found that there is a phenomenon of single vortex and double vortex coexisting in the Vane-less area between guide vane and impeller blade of the pump turbine. Through the experimental research in this paper, it can provide useful help for understanding the vortex separation on different quadrant working conditions inside the pump turbine.
A Simplified Francis Turbine for Micro Hydro Application: Design and Numerical Analysis
Authors: Dahal Dadi Ram , Neopane Hari Prasad , Thapa Biraj Singh , Paudel Nikshan , Chitrakar Sailesh , Thapa Bhola 
Published: January 2021

Abstract
Francis turbine is the most widely used type of hydro turbine due to its high efficiency and a wide range of operation. Despite its popularity in large scale power plants, the use of these turbines has not been yet realized for micro hydro applications. Considering the sustainability of micro-hydro power plants, the components of Francis turbine need some simplifications so that the manufacturing and operation of the turbine become more feasible. This study focuses on redesigning the turbine with simplifications in spiral casing and distributor along with investigating its effects on the performance of runner using CFD. Bovet method is used to obtain meridional dimension of runner while Bladegen feature of ANSYS 15.0 is applied to obtain the runner domain. Optimum design of the runner is obtained by analyzing the effect of parameters like wrap angle, lean angle, blade’s beta angle distribution and energy distribution on the runner’s performance. The velocity at the runner inlet is very low for micro Francis turbine which increases the dimension of spiral casing so dimension of spiral casing is made small by adjusting guide vane and stay vanes. A comparative study of conventional and simplified design is made based on pressure and tangential velocity distributions along spiral casing and distributor as well as on the performance of turbine. It is observed that the required reaction ratio and flow conditions can be obtained by combining the stay vanes and guide vanes. In addition, the proportion of combination depends on the magnitude of reaction ratio. It is found that the combining the stay vane and guide vane gives better result in best efficiency point however at other loading condition efficiency is lower which is due to improper stagnation.
Current research in hydraulic turbines against sediment erosion: International partnership and collaborations
Authors: Thapa Biraj Singh , Thapa Bhola , Dahlhaug Ole Gunnar , Lee Young-Ho , Zhongdong Qian 
Published: January 2021

Abstract
The problem of material erosion in hydraulic machineries has been under the investigation since a century ago. However, the proper solutions to the erosion of hydro turbine due to sediment-laden flows has not been found yet. The new and future hydropower development is shifting towards Asia region, which holds the highest capacity of undeveloped hydropower potential worldwide, and is also the largest contributor of the sediment intake to the ocean through its river systems. At present the various academic and research institutions are making advancements in R&D of hydraulic turbines against sediment erosion. This article highlights some major achievements made by Kathmandu University and its consortium partner intuitions in the advancement of the turbine technology for the future market.
Effect of the flow upstream the impeller inlet on flow instability of a centrifugal pump
Authors: Ye W X , Li X J , Zhu Z C , Luo X W 
Published: January 2021

Abstract
Under part-load conditions, flow instability phenomena in a hydraulic machinery could lead to strong pressure fluctuations and vibrations, posing a great threat to the safety of the units. This paper analysed unsteady flow in a centrifugal pump (specific speed of 39 min−1·m3s−
1·m) with different inlet geometries under part-load conditions. An advanced turbulence model, PANS (partially averaged Navier-Stokes), acting as a bridge from RANS to DNS, is applied for numerical simulations. The results indicated the pump with a straight inlet pipe reached higher values of pump head and efficiency near the design point than the test pump with a non-straight inlet pipe. According to the characteristic curves, hump phenomenon was observed at 0.75ϕbep for the pump having a straight inlet pipe, while it occurred at 0.5ϕbep for the test pump. Under the condition of a low flow rate i.e. ϕ=0.5ϕbep, there is strong pre-swirling flow upstream impeller inlet for the test pump, which contributes to the propagation of rotating stall cells; But energy loss in the impeller inlet of the pump with straight inlet pipe is slightly higher than that in the test pump due to the presence of the stationary stall cells, which causes large energy loss in the impeller and the passage upstream impeller inlet. Further, rotating stall cells are captured in the impeller in both pumps under the condition of ϕ=0.75ϕbep.
Efficiency and Mechanism of Advanced Treatment for Phosphate Wastewater by High Efficiency and Low Consumption Coagulation and Phosphorus Removal System
Authors: Dai Yan , Li Ye , Ke Yi , Li Bo 
Published: January 2021

Abstract
Beaker coagulation experiments were carried out using polyaluminium chloride (PAC), polyferric sulfate (FPS), polyacrylamide (PAM), polyaluminum chloride (PAFC), polyaluminum sulfate (PAFS) and polyacrylamide (PAFC). The phosphorus removal effects of several flocculants were compared. The best combination coagulant PAM-PAC/PFS with high efficiency and economy was selected. The best ratio of PAC/PFS is 1:1, and the dosage of PAM is 1mg/L. The experiment determined the optimal hydraulic conditions: fast agitation and addition of PAC/PFS at a speed of 400 r/min for 1 min. PAM was added during slow agitation at a speed of 100 r/min for 6 min. The phosphorus removal system has a good effect on the removal of total phosphorus and other water quality indicators in the mine drainage of many phosphate mines, and all of them can meet the discharge standards.
Research on the status quo and countermeasures of Municipal solid waste classification in Fuzhou
Authors: Li Qiaoqiao 
Published: January 2021

Abstract
Since Fuzhou started garbage sorting, it has achieved certain results. However, there are still many problems in the specific implementation process. Starting from the analysis of the status quo of domestic waste classification in Fuzhou City, the article analyzes the main problems existing in the current domestic waste classification work in Fuzhou, such as residents' awareness of waste classification needs to be improved, waste classification hardware facilities are not perfect, etc., and on this basis, corresponding The countermeasures will play a positive role in further promoting the garbage classification in Fuzhou.
Long-term variation of Chlorophyll-a concentration in Qingdao coastal area from MODIS data
Authors: Zhou Yan , Gai Yingying , Liu Xiaoyan 
Published: January 2021

Abstract
Qingdao coastal water is an important area that provides with traveling, mariculture, etc. On the basis on MODIS satellite remote sensing data from July 2002 to June 2014, the spatial-temporal variation of Chlorophyll-a concentration in Qingdao coastal area are presented, and the results show that, an obvious decrease of Chlorophyll-a concentration from offshore to onshore in a pattern parallel to the coastal line is revealed. The monthly mean Chl-a concentration is the lowest outside the Jiaozhou Bay, the highest in the bay in summer, and the lowest in the bay, the highest in the bay mouth in winter. The variation of yearly average Chl-a concentration shows that it keeps the volatility in the bay and the bay mouth, but slowly rising outside the bay. The temporal and spatial features of the Chl-a concentration in the Qingdao coastal area were affected by the variations of the marine environmental factors, such as light, nutrients, ocean currents, sea surface temperature, mixed layer depth, also related with ingestion of zooplankton and so on.
Research Progress of heavy metals remediation in soil by ionic liquids
Authors: Jia Xiaoqiao , Liu Baoyou 
Published: January 2021

Abstract
At present, heavy metal pollution of soil has become increasingly serious. Soil heavy metal pollution has caused great harm to the environment and human health. Therefore, this paper reviews the sources and hazards of heavy metals in soil, the properties and applications of ionic liquids, research on the remediation of heavy metals in soil by ionic liquids and its unique advantages compared with physical remediation, chemical remediation, biological remediation and combined remediation, and put forward the future development direction.
Ecological security evaluation of Panjin city on town scale
Authors: Lv Jiujun , Liu Lanxin , He Jun , Li Daoning , Zhang Chao , Zeng Xiangling 
Published: January 2021

Abstract
With the double pressure of rapid economic development and ecosystem degradation, the ecosystem of Panjin wetland has been damaged to different degrees. Early warning research on ecological security in this region can provide decision-making basis for the ecosystem protection and management. Taking Panjin as the study area, the ecological security level of all towns in Panjin was evaluated by establishing the warning system of Panjin ecological security. The results showed that on the town scale, there were 20 towns or regions in the warning level of grade III or grade IV, indicating that the ecolsystems in these areas were in general and good situation with the integrated value of ecological security from 0.41 to 0.71. Other 11 towns or regions, most of which were located in the northeast of Panjin had ecological security warning level of grade II, with the integrated value of ecological security from 0.28 to 0.39. These towns often have higher economic development level and less ecological protection measures. Therefore, when the government makes policies in these towns, more wetland ecological protection plans should be fully taken into account.
Application of Principal Component Analysis in Meteorological Forecast
Authors: Ling Zhonghua , Gao Yushan , Chen Qiang 
Published: January 2021

Abstract
Based on the principle of weather dynamics, this paper studies that the pressure gradient, the temperature gradient and the high-altitude guiding wind are the three major types of factors that affect strong winds, and forms three strong wind prediction factor groups. Multiple indexes are transformed into a few linearly independent comprehensive indexes by principal component analysis (PCA). After the factor index is standardized, the comprehensive index of gale forecast is obtained based on PCA. The test results show that the Beibu Gulf gale wind speed has a good corresponding relationship with the gale forecast comprehensive index (the first 24 hours), and the trend basically corresponds to the peak-valley value, which shows that the comprehensive index has a good indication significance for gale forecast. The comprehensive index 30 can be taken as the starting threshold for forecasting strong winds in Beibu Gulf, which has a good reference value for forecasting the presence or absence of strong winds and is a useful discussion for quantifying the forecasting method of weather conceptual model.
Treatment of pharmaceutical sludge by wet oxidation under mild reaction conditions
Authors: Gan Xiaoming 
Published: January 2021

Abstract
In this study, the wet oxidation treatment of pharmaceutical sludge was investigated. The effects of the reaction parameters on the removal rate of volatile suspended solids (VSS) and the total chemical oxygen demand (COD) were discussed. The results illustrated that the highest could reach up to 68.9% and 93.7% separately under 260 °C with initial oxygen pressure 1.5 MPa and the reaction time 60 min. The addition of Cu2+ could increased the COD removal rate significantly. The results demonstrated that wet oxidation showed promising as an economical and feasible alternative for the pharmaceutical sludge treatment.
Synthesis and crystal structures of four ladder distannoxane dimers
Authors: Gao Zhongjun , Zhang Haifeng , Sha Jingquan 
Published: January 2021

AbstractFour distannoxane dimers [ClR2SnOSnR2X]2(X=Cl, R=PhCH21, 2-FC6H4CH22, 2-ClC6H4CH23, X=OH, R=2,4-ChC6H3CH24) have been synthesized by the hydrolytic reaction of (PhCH2)2SnCh with soditma alkoxides. And all these four complexs were characterized by elemental analysis, IR,1H NMR spectroscopies and X-ray diffraction. All compounds were assigned tetranuclear distannoxane structures in solid state, which contain so-called ladder arrangement with a central planar Sn2O2four-membered ring. The endo- and exo-cyclic Sn atoms are both five-coordinate, and have distorted trigonal bipyramidal geometries.
The Culture of Salt-Tolerant Strains and its Degradation Performance of High-salt organic Wastewater
Authors: Li Yinghan , Luo Zheng , Guo Fengbo , Zhang Kaizhi , Zhou Qiao , Cheng Qunli 
Published: January 2021

Abstract
High-salt wastewater refers to the wastewater containing more than 1% of total salinity in domestic wastewater and industrial wastewater. The wastewater contains relatively high levels of inorganic ions such as Cl-, SO4
2-, Na+, and Ca2+, which will inhibit the growth of microorganisms, making it one of the extremely difficult to treat wastewater. In this study, the known saline-alkali soil was used as a sample source, and halophilic strains were screened out using shaking, culture, and domestication methods. The morphological characteristics were observed by light microscopy. Microscopic examination showed that the strain was a milky white colony, round or Oval shape, smooth and moist, convex lens surface, moderate area, opaque, bulging in the middle, edge is not spread, the same color on both sides. The effects of salt concentration, culture time, initial organic wastewater concentration, and strain size on the degradation performance of the selected strains were studied. The experimental results show that: when the salt concentration of wastewater is 20%, the initial organic wastewater concentration is 2000mg L-1, the added culture volume is 20 ml, the culture time is 72 hours, the COD removal rate of wastewater can reach 66.4%.
Corrosion Protection of Aluminum Alloy Skin for Long-Term Parking Aircraft
Authors: Chen Yuqin , Xing Ruishan 
Published: January 2021

Abstract
The previous research mainly focused on the corrosion protection of aircraft in service, rarely involved in the corrosion protection of long-term aircraft on ground in Colleges and universities. There are many similarities and differences between the aircraft in service and those AOG aircraft. In order to ensure the structural safety of the aircraft, corrosion protection must be carried out. However, because it no longer needs to fly to the blue sky, the requirements of corrosion protection are also different from the aircraft in service.
Study on noise reduction of rainfall at Shizhu Station and protection of villages along Nanxi River
Authors: Liu Yixi , Guo Huifang 
Published: January 2021

Abstract
Nanxi River is one of the largest tributaries in the lower reaches of Oujiang River. There are many traditional villages along the river. When there are more rainy seasons or typhoon storms, floods will occur in the basin. There is Shizhu hydrological station on the main stream of Dananxi in the lower reaches of the basin. Shizhu station is the flood control station in the middle and lower reaches of Nanxi River, which plays an important reference role in flood prevention of Nanxi River. Due to the influence of many factors, rainfall data contains system noise and measurement noise. The analysis and calculation of the model parameters from the rainfall series with noise can not truly reflect the nature of the rainfall system. The reliability of data and the accuracy of data analysis results can be improved by denoising rainfall series. In this paper, the wavelet denoising method is used to denoise the annual rainfall series of Shizhu station, and its useful rainfall data is obtained. The amount of rainfall has a direct impact on the socio-economic development along the line, the health of the ecological environment and the people's living and working in peace and contentment on both sides of the Nanxi River. The research results can provide basic data for flood control and water resources utilization of Nanxi River, and enable relevant departments to take measures in advance to ensure the safety of people's living environment and sustainable development of ecological environment, and provide technical support for Rural Revitalization in Nanxi River.
Research on Reserve Classification of Solid Mineral Resources in China and Western Countries
Authors: Zuo Mingxing , Wang Tao 
Published: January 2021

Abstract
Combined with the development and application of mining markets at home and abroad, the following understandings are obtained through comparative analysis of GB/T 17766-1999 Classification for resources/reserves of solid fuels and mineral commodities, GB/T 17766-2020 Classification for resources/reserves of solid fuels and mineral commodities and JORC Code. 1) GB/T 17766-2020 is more concise and efficient, focusing on the objective evaluation of economic value; 2) Since the form and connotation of GB/T 17766-2020 is similar to JORC Code and other Western norms, the implementation of GB/T 17766-2020 will be conducive to international integration; 3) A variety of factors caused the low recognition of domestic reports and small market influence. However, according to GB/T 17766-2020, we can gradually improve the recognition and influence by means of strengthening process management and responsibility to natural persons.
Slope Stability Analysis Based on the Limit Equilibrium Method and Strength Reduction Method
Authors: Jin Yuancheng 
Published: January 2021

Abstract
To evaluate the stability of the slope in Tianmogou, Southeast Tibet, the results of 3D modeling were introduced into the computer-aided design section for the numerical analysis of the limit equilibrium method (LEM) and strength reduction method (SRM). The analysis results show that the safety coefficients calculated by the LEM and SRM are similar and more accurate than those of other ideal models. The LEM and SRM are applied to the slope stability analysis, which can reflect the slope stability more accurately.
Status analysis and development of reservoir numerical simulation technology
Authors: Qiao Xudong 
Published: January 2021

Abstract
In recent years, with the continuous development of computer, applied mathematics and reservoir engineering, reservoir numerical simulation method has been improved and widely used. Through numerical simulation, we can make clear the fluid flow law, oil displacement mechanism and spatial distribution of remaining oil in the reservoir; study reasonable development scheme, select the best production parameters, and obtain the highest recovery factor and maximum economic benefit with the least investment and the most scientific production method. In order to meet the needs of the development of petroleum industry, reservoir numerical simulation technology has made great progress in recent years. The appearance of the development direction of fine reservoir numerical simulation is the most intuitive display of this progress. Therefore, this paper carries out a specific study on the research status and development trend of fine reservoir numerical simulation, hoping that this research can make more people understand the multi-disciplinary and one-dimensional The development trend of fine reservoir numerical simulation, which includes physical, high-speed, multi-functional integration and system coupling simulation.
Pore-scale investigation of factors influencing polymer flooding in dual-permeability porous media
Authors: Hu Jie , Li Aifen 
Published: January 2021

Abstract
In present work Cahn–Hilliard phase field coupled with Navier-Stokes equations were solved using finite element method to simulate polymer flooding in a dual-permeability porous medium, the effect of injection rate, oil viscosity and oil density on polymer displacement oil process was quanlitatively and quantitatively investigated. The simulated models realistically captured the micro mechanism during polymer flooding, e.g., oil film thinning and rupture, profile conformance enhancement. The result shown that with the injection rate increase, water displacement efficiency increase, however, an optimal injection rate exists for water flooding in dual-permeability porous media. under the intermediate injection rate flooding, polymer flooding could gain an incremental oil recovery up to 40.7%.
Study on the relationship between the direction of air flow and the dust control effect in integrated excavation surface
Authors: Zhi Li 
Published: January 2021

Abstract
In order to improve the dust control effect of integrated excavation surface, FLUENT was used to simulate the relationship between different inlet air flow direction and working face dust concentration distribution to study the relationship between inlet air flow direction and dust control effect of integrated excavation surface. In combination with field tests, the corresponding wall air duct was selected and processed and applied to engineering practice. The results show that different air distribution directions have different influence on the dust control effect of working face. When the Angle of radial air outlet is 0°, the air flow directly acts on the transport belt to form secondary pollution, and the dust control effect is not good. The best dust control effect is 15° or 30°.
An Experimental Study on optimizing the particle size distribution of bridging agents in drilling fluids
Authors: Hui Cheng , Ma Chengyun , Tian Deliang , Luo Chao , Zou Lingzhan , Wang Haige 
Published: January 2021

Abstract
Managing lost circulation has always been a serious challenge in the oil industry. This situation becomes further complicated when shale formation is involved. Particulate lost circulation materials (LCMs) have been used to prevent the drilling fluid from entering fractured, cavernous, or high-permeability formations for many years. However, existing LCMs are inefficient in terms of size and application methods in solving severe-to-total losses in shales due to the uncertainty of particle size distribution (PSD) in drilling fluids. This study focuses on an experimental method optimizing the PSD of solid particles in the drilling fluid at high temperature and pressure. An orthogonal experiment of L9 (3)4, including four factors and three levels, was designed to investigate the relationship between the PSD of solid particles and filtration loss. Results indicate that the orthogonal design method contributes to the optimization of the PSD of solid particles in the drilling fluid and reduce the test time and experimental workload during the drilling fluid process in the design stage. In addition, a polynomial relationship between the cumulative filtration loss and D90 or D50 is verified experimentally in this study. This study will remarkably benefit the drilling technologists in resolving the issue of lost circulation.