bluuebunny/crossref_metadata_2025 huggingface dataset:
Retrospective analysis of phytoplankton community structure in water bodies of South Ural (Russia)
Authors: Kostryukova A , Mashkova I , Shchelkanova E , Trofimenko V
Published: January 2021

The current paper considers changes of phytoplankton community structure in three South Ural (Russia) water bodies different in trophicity: Lake Uvildy, Lake Ilmenskoe, and Shershnevskoe Reservoir. There is no clear relation between the changes of species structure of phytoplankton communities and water-bodies trophicity. The least significant changes in the phytoplankton community structure are registered for the mesoeutrophic Lake Ilmenskoe, which is located on the territory of the State Reserve. Diatomic, green and blue-green algae groups are the most diverse in composition in the studied periods of 1936-1937, 1964-1984 and 1998-2016. But for the last 20 years, Cyanophyta has increased its contribution into the phytoplankton number and biomass of Lake Ilmenskoe. The representatives of the Bacillariophyta group dominate in oligotrophic Lake Uvildy. In 1965-1985, the Chlorophyta group was the most abundant in Shershnevskoe reservoir (34 % of the total number of species), Bacillariophyta -32 % and Cyanophyta – 18 %. In 2003-2005 and 2017 the number of green algae increased (Chlorophyta – 40 %) and that of diatoms decreased (Bacillariophyta -21%) with the number of blue-green algae being unchanged (Cyanophyta -19 %). The ecological status of the Shershenevskoe Reservoir has transformed from a long-term sustainable mesotrophic to eutrophic. So, for oligotrophic lake Uvildy and mesoeutrophic lake Ilmenskoe, Bacillariophyta group is characterized by the greatest taxonomic diversity. While for eutrophic Shershnevskoe Reservoir the absolute abundance of Chlorophyta algae group is marked, which is growing in time. The growing importance of blue-green algae is one more feature of the change of a trophic status.
Effects of ecological water diversion in coastal plain river network considering different control plans
Authors: Wang J M , Wu J F , Fu L , You A J
Published: January 2021

The water environment in coastal plain river network becomes serious due to its dense population and low flow rate, the ecological water diversion is widely accepted as an effective method to improve the water quality in coastal areas. As a typical coastal city in China, Pinghu city has suffered from the serious water quality problem for years especially in the downtown area. Therefore, the local water diversion project has been constructed since 2010 for the purpose of providing an efficient way to improve the river network water quality. However, a systematic research of the control plan of water diversion is still necessary. In this study, a numerical model is introduced to predict the improvement of river network water quality considering different control plans. The simulation results comparison among different water diversion control plans show than the pre-drainage plan obtains the best water quality in this coastal plain river network, and it becomes a good choice for the local government to further improve the regional water environment.
Study on modulation technology of highway regional wind field
Authors: Li Y Y , He Y K , Hao S F , Jia Y
Published: January 2021

In this paper, through numerical simulation, the modulation effect of trees on the wind field of the highway and the wind load of the traffic is studied. Two tree species were selected, and the effects of different tree species and arrangement numbers on the wind speed on the embankment and the wind pressure on the driving surface were studied, by simulating the single-row distribution of a single tree species and the mixed multi-row distribution of two tree species. The results show that trees play a significant role in wind field modulation, and different tree species have different effects; Compared with the modulation of single tree species, the mixed modulation effect is more effective, and gradually increases with the number of rows, but the trend of enhancement gradually slows down.
Heavy metal pollution characteristics and assessment of environmental quality and safety of facility agriculture soil in Shouguang
Authors: Zhang J , Xue Q , Chen Q F , Zhao C S , Liu W , Li Q
Published: January 2021

Taking Shouguang Facility agriculture in Weifang City as the research object, heavy metals and other pollutants in new and old facility agriculture soil were investigated and analyzed from 2017 to 2019. The content of heavy metals in soil was analyzed, and the environmental quality of heavy metals was evaluated by single-factor pollution index method and Nemerow index method. The correlation between heavy metal content in surface soil and cultivation years, vertical distribution of heavy metal content in soil, frequency distribution of heavy metal in surface soil, and correlation between heavy metals in surface soil and soil nutrients were analyzed. The results showed that the average contents of the eight heavy metals were Cd 0.23 mg•kg−1, Hg 0.05 mg•kg−1, As 8.09 mg•kg−1, Pb 23.31 mg•kg−1, Cr 70.81 mg•kg−1, Cu 38.54 mg•kg−1, Ni 25.87 mg•kg−1 and Zn 147.52 mg•kg−1. Aside from Pb and Ni, the average content of all other heavy metals in the surface soil of facility agriculture was higher than the average of the control and the geochemical background level of soil in Weifang. Compared with the Environmental Quality Evaluation Standard for Farmland of Greenhouse Vegetables Production (HJ333-2006) and the Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land (trial) (GB15618-2018), the average content of heavy metals met the standards, with Cd, Hg and Zn content in some samples exceeding the standards. Most surface soil environmental quality is clean or relatively clean, but there is also part of the soil has reached the level of mild or moderate pollution. The content of heavy metals in the soil of the old facility agriculture (cultivation years > 10) was higher than that of the new facility agriculture (cultivation years ≤ 10), and the content of heavy metals in the surface soil (0∼20cm) was higher than that in the deep soil. The quality distribution of heavy metals in the surface soil is affected by exogenous heavy metals, among which Hg and Cd have the largest skewness coefficient and are most affected by exogenous. There was significant positive correlation between heavy metals in surface soil and available phosphorus, hydrolytic nitrogen, available potassium and organic matter. The results indicated that the accumulation of heavy metals in soil was related to the application of organic fertilizer, phosphate fertilizer and compound fertilizer.
Monitoring of soil erosion caused by construction projects using remote sensing images
Authors: Qiu T , Lu F C , Zhang J J , Wang R
Published: January 2021

The application of Remote Sensing (RS) images to soil erosion monitoring caused by construction projects can meet the needs of dynamic supervision and early warning, and can also significantly improve the efficiency of supervision. In this paper, a technical process for monitoring soil erosion caused by construction projects was proposed. As an example, the high-definition RS survey of the whole city of Zhoushan was carried out. Firstly, the contour lines of the protection range determined during the approval of the construction project were vectorized. Secondly, RS interpretation of perturbation patches of construction projects was carried out with the aid of interpretation marks. Thirdly, preliminary judgment of perturbation compliance was made through the spatial overlay of the interpretation results and approved prevention scope. Finally, field investigation was done to correct the results of RS image analysis. The results show that this technical process can interpret the activity status of construction projects, effectively determine the compliance of perturbation conditions, and improve the efficiency of soil-water conservation supervision.
Application of smart waste management in the Department of Civil Engineering, Bali State Polytechnic
Authors: Pertiwi I G A I Mas , Kristinayanti W Sri , Andayani K Wiwin , Aryawan I G M Oka , Putri Indrayanti A A , Sudiarta K
Published: January 2021

The existence of the green campus program is expected to create awareness and concern for the campus community to participate and be responsible for reducing global warming. This research is expected to be a guideline in implementing smart waste management in the Civil Engineering Department of the Bali State Polytechnic in particular to improve quality in the environmental sector. The method of analysis in this research includes: Identification, planning of and quantity of waste generation. The analysis conducted in this study used an analysis referring to several standards regarding green campus, namely UI Greenmetric, Green Guide for University and Greening University Toolkits. Waste management in the Department of Civil Engineering has not carried out processing efforts such as recycling, composting or other integrated efforts. The waste generated from teaching and learning activities, practicum and canteen is carried out by making a reservoir and it is carried out by disposing of waste into the trash bins that have been provided, practicum waste is collected in carts, waste management is carried out in the area of the department such as in the room carried out by cleaning services, which is then the final handling in the campus area, namely garbage is disposed of to the Temporary Landfills (TPS) campus then brought to the Landfills (TPA) by the South Kuta District Sanitation Office. The main objective of the campus solid waste management plan is to maximize resource recovery, with the aim of minimizing the disposal of waste to the TPS. The main strategy is to implement a waste hierarchy by avoiding purchasing products that will eventually become waste, repair and reuse, then recycle, and finally if there is no other choice, disposal to the TPS.
Risk management of Material Laboratory, Department of Civil Engineering, Bali State Polytechnic for preparation of Occupational safety and health program
Authors: Pertiwi I G A I Mas , Aryawan I G M Oka , Kristinayanti W Sri , Andayani K Wiwin , Putri Indrayanti A A , Sudiarta K
Published: January 2021

The purpose of this study is to determine the risks and hazards in the laboratory, it is necessary to identify hazards, risk assessment and risk control. Laboratories are often found in research and development institutions, service companies, industry and universities. The material laboratory is a place to carry out student practicum activities and conduct research which has a source of danger that can cause work accidents such as chemical explosion, fire, poisoning and ext. Work accidents can be avoided by improving the quality of Occupational Safety and Health (OSH) which is related to the process of doing work safely and working conditions that are safe and comfortable. One effort that can help is to identify hazards and risk assessments so that effective control efforts can be made to increase work productivity and reduce work accidents. Hazard identification is a process that can be carried out to identify all situations or events that have the potential to cause work-related accidents and diseases that may arise in the workplace [1]. Carry out hazard identification to answer the question of what potential hazards can occur or befall the company organization and how it can occur. Hazard identification is the first step in developing OSH risk management and a systematic effort to understand the existence of organizational hazards and is the foundation of an accident prevention and risk control program [2].
Numerical investigation of the grooves effect on the inlet flow characteristics and hydraulic performance of an axial-flow pump
Authors: Zhang Rui , Mu Tong , Xu Hui , Qian Xiangdong
Published: January 2021

In this paper, the axial position of the grooves effect on the inlet flow characteristics and hydraulic performance of an axial-flow pump is studied by numerical method. The computational results show that setting the grooves on the pump inlet pipe could significantly improve the inflow characteristics of impeller and the saddle zone would be effectively suppressed. Under the deep stall condition, the grooves could improve the axial velocity of inflow and effectively reducing its streamline bending degree, and it also can block and destroy the vortex structures and then dissipate them rapidly. Reducing the axial distance between grooves and impeller can improve the hydraulic performance and the inflow characteristics of axial-flow pump.
Investigation of the groove effect on the tip leakage vortex flow
Authors: Fei Zhaodan , Zhang Rui , Xu Hui , Mu Tong
Published: January 2021

The groove effect on the tip leakage vortex around a NACA0009 hydrofoil was studied by numerical method. The results show that, as the groove angle is 45°, the groove could enhance the turbulence kinetic energy around the TLV, weaken the TLV strength and improve the pressure in the TLV core, resulting in an efficient suppression effect on the TLV cavitating flow. When the groove angle is 0° and 45°, the groove could decrease the tip leakage flow rate and the TLV gets lower and moves away from the tip gap. As the groove angle is 90° and 135°, the tip leakage flow rate gets larger, and the TLV gets higher and closer to the tip gap.
Non-dimensional study on the start-up process of a centrifugal pump and its related pipe system
Authors: Meng L , Wang W P , Liao C L , Zhao L C , He L , Zhang C Y
Published: January 2021

Hydraulic transient processes sometimes bring with it violent or dramatic unsteady phenomenon, which would interfere the normal operation or even damage the system. The start-up of a centrifugal pump with cavitation can lead to serious transient phenomenon. One dimensional calculation (Method of characteristics) was widely used to solve transient problems, but its drawback is lacking of details for the flow characteristics inside the pump, 3D simulation for transient process simulation needs huge computer resources. A simulation method that coupled MOC and 3D simulation (CFD) was frequently used for solving complex transient problems in these years. The results of the coupling simulation are usually complex when cavitation happens and disappears quickly during the short start-up period, a simplified method to describe the process is necessary. A centrifugal pump and its related system were simulated with a coupling method. Dimensionless mass flow rate, head and cavitation conditions of the pump was used to analyse the start-up process. It was proved that the non-dimensional study method can make the whole process more intuitive and easier to understand.
Calibration of Winter-Kennedy coefficients on a Bulb turbine based on current-meter method
Authors: Cao Dengfeng , Pan Luoping , Zhou Ye , Qu Litao
Published: January 2021

Field measurement of discharge has been performed for a Bulb turbine based on current-method in this paper. Winter-Kennedy coefficients of this machine are calibrated based on the test results of integrated discharge and measured flow differential pressure between bulb head and stay cone. Calibration shows that discharge and flow differential pressure of the test machine follow the power model very well. The uncertainty of discharge estimation by Winter-Kennedy method for Bulb turbine is discussed finally.
Comparison of the effects of leakage flow from guide vanes of different hydrofoils using alternative clearance gap approach
Authors: Gautam Saroj , Lama Ram , Neopane Hari Prasad , Thapa Biraj Singh , Chitrakar Sailesh , Zhu Baoshan
Published: January 2021

Sediments flowing along with water through guide vanes induces abrasive and erosive wear in the GV surface. The effect of these wears differs with the shape of GV profiles. This study presents an alternative clearance gap method to compare the effects of clearance gap (CG) in the GV of Francis turbine with different hydrofoils. Numerical prediction of the performance of Francis turbine with symmetrical and asymmetrical hydrofoils is studied with the CG of 0 mm, 2 mm, and 4 mm thickness. Increase in the size of the gap deteriorates the performance of the runner. In case of asymmetrical GV profile, the effects in the runner is found to be less than the symmetrical profile. It is due to lesser pressure difference between the adjacent sides of the GV profile. With the alternative clearance gap approach, it distinguishes the effect of CG and the pressure pulsation due to rotor-stator interaction for a single numerical model.
Numerical investigation on flow distortion in a vertical inline pump
Authors: Tang Yajing , Si Qiaorui , Gan Xingcheng
Published: January 2021

The vertical inline pump is a centrifugal pump with special structures of curved inlet pipe before the impeller, and it is widely used in where the constraint is installation space. However, the elbow inlet with different angles and cross sections also deteriorates the impeller inflow and results in flow distortion in the impeller. For the purpose of further investigation of flow distortion in the vertical inline pump, the unsteady Reynolds averaged Navier-Stokes equations were solved by the commercial CFD code with the shear stress turbulence model. The normalized coefficients of inlet velocity, pressure, helicity, and non-uniformity were applied to quantitatively analyze the flow distortion in the pump. The computational results showed a great agreement with the experimental results. Under the nominal and overload conditions, the flow separation and counter-vortex pair were found on the outer side of the inlet pipe and the intensity of these phenomenon increases along with the rise of flow rate. However, the flow recirculation was observed under the part-load condition which becomes the major reason for the flow distortion in the inline pump.
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

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

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

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

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

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

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

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

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

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

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

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

Four 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

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

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

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

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

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

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

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

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

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.
Design simulation and test of hydraulic control system of RFID reamer while drilling
Authors: Zhao Jianjun , Liao Hongqian
Published: January 2021

With the gradual improvement of exploration and development in deep and ultra-deep Wells, the demand for slim-hole drilling is increasing day by day. However, both the phenomenon of neck constriction and drill-jamming accident occur from time to time in the drilling process, and the annulus clearance between borehole and casing is too small, which resulting in high slurry annulus pressure loss, low displacement efficiency and poor cementing quality. Therefore, a kind of RFID reamer while drilling has come into being, the reamer blades can be controlled to open and close with the aid of RFID tag recognition technology without increasing the drilling cost, so as to complete the reaming operation while drilling. Taking the hydraulic control system as the research object, the hydraulic circuit has been designed based on AMESim software in this paper, so has its dynamic performance simulation analysis been carried out, finally, the ground test has been completed, the results show that the hydraulic control system is capable of accurately identifying the RFID tag information to drive the reamer blades to open and close, the overall pressure loss of the tool is about 1.0 MPa as the blades opened completely, which meets the requirements of field test.
Optimization Selection Research of Chemical EOR Pilot Project Site for Umm Niqqa Oilfield in Kuwait
Authors: Zhu Hongzhang , Song Mingming , Zuo Qin , Zhang Hong
Published: January 2021

The Low Fars of Umm Niqqa oilfield in northern Kuwait is a carbonate formation. After many years of primary and secondary oil recovery, Kuwait Oil Company has started to use chemical EOR flooding technology to increase recovery in this reservoir in recent years, and plans to carry out chemical EOR Pilot project. Due to the dense well pattern and surface facilities in the oil field, the site selection of the pilot project has become a problem. This essay focuses on the optimization method of the pilot project site, underground influencing factors, surface influencing factors, and analysis of the preferred site. Therefore, several important conclusions for selecting the site of the pilot project are summarized: simplifying the site design, combining local geological conditions and construction experience of similar projects, will greatly reduce investment and improve the efficiency of the chemical flooding pilot project. The successful pilot site selection of Umm Niqqa water and polymer flooding pilot projects based on underground design and surface foundation includes well site selection and water source selection. Reserve the surrounding site in advance, drill new wells in this area, install and connect the corresponding water injection pipelines and manifolds to ensure the successful implementation of the chemical flooding pilot project.
Damage evolution model of cemented tailing backfill based on acoustic emission energy
Authors: Wang Liang , Xie JinCheng , Qiao DengPan , Wang Jun , Huang Fei
Published: January 2021

Tailings cemented backfill is widely used in the production activities of mine management goaf, and it is also one of the main technologies to realize green mining and safety production. In this paper, the cyclic loading and unloading test of cemented tailing backfill is carried out based on acoustic emission technology, the evolution trend of AE energy in the loading process is analyzed, the damage variable based on AE energy is defined, and the damage evolution equation of cemented tailing backfill based on AE energy is established, and the quantitative relationship between AE energy and damage energy release rate is explored. It provides basic research basis for bearing process analysis and failure prediction of cemented backfill in mine site.
Research on Prediction Method of Drilling and Falling Recovery Law in Productivity Area
Authors: Jia Xueyan
Published: January 2021

With the expansion of production scale in recent years, the drilling drop in Sazhong Development Zone has a greater impact on output. From the statistics of recent years, the annual output of drilling drop affects an average of 106,000 tons, which is 2 to 3 times the output of new wells that year. Judging from the characteristics of the dynamic changes in the whole process of drilling and dropping, there are great differences in the dynamic changes in different blocks, different oil layers and different well spacing conditions. The dynamic response time of the Sapu oil reservoir is earlier than that of the Gaotaizi oil layer; the smaller the well spacing, the earlier the dynamic response time; However, there are few conclusive literatures on the effects of drill-down, and there is little discussion on the degree of drill-down effects. In order to further study the drill-down rule under different well patterns, different pressure levels, and different oil layer properties, and to further quantitatively study the degree of the drill-down effect, this paper takes the North East Block Duandong block as the research object, and analyzes different wells during the drilling recovery process. The in-depth study of the factors affecting the drill-down under different conditions of the network, pressure level, and different oil layers is carried out, and the law of drill-down recovery is summarized; combined with the theory of percolation, mathematical statistics is used to predict the influence of the drill-down to arrange the production operation for the next year As well as the preparation of the drill-down recovery plan to provide theoretical guidance.