bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance evaluation of a novel viscosity-reducing agent for heavy oil
Authors: Liu Guoliang , Li Xuening , Zhang Fusheng , Liao Gongqing , Li Yikun , Sun Jianghe , Zhu Zhuoyan 
Published: April 2020

Abstract
Heavy oil has high viscosity, high content of resins-asphaltenes and poor fluidity, which makes it difficult to produce. In the early research, a novel viscosity-reducing agent with high molecular weights and various active groups was synthesized in the laboratory. Ion composition analysis of wastewater and heavy oil viscosity test of Jincai 27 well were carried out. The emulsifying and viscosity reducing properties of a novel viscosity-reducing agent for heavy oil under low shear condition were evaluated by water content change of emulsion phase and viscosity reduction rate. The results showed that under 50 °C and low shear (10∼20s−1) condition, the viscosity-reducing agent solution had a fast emulsifying speed for the heavy oil. The O/W emulsion with good emulsion stability formed after about 60min shear. The viscosity reduction rate for the heavy oil was above 90%. The emulsion micrographs showed that the emulsion was highly dispersed and the particle size was uniform with diameter of 2 microns or even lower. The viscosity value of viscosity-reducing agent solution with concentration higher than 1200 mg/L could reach 25.0mPa.s under 8.0s−1 shear rate and 50°C, which indicated that it had a certain thickening property. Artificial core flooding experiments showed that viscosity-reducing agent flooding could increase heavy oil recovery by more than 10% compared with water flooding.
Characteristic analysis and prediction technology of cooling, heating and power load in energy internet town of Xiongan New Area
Authors: Hou Lei , Yang Bo , Jia Na , Wang Zichi , Zhang Zhengwen , Zhang Yajie 
Published: April 2020

Abstract
Xiongan New Area is another important new area after Shenzhen Special Economic Zone and Shanghai Pudong New Area. According to the development strategy of high-point positioning of the new area, providing safe, reliable, clean and economic modern energy system for Xiongan New Area is one of the important tasks in the construction of the new area. In the process of establishing and optimizing the energy system, reliable data of energy consumption and load characteristics should be obtained first. This paper analyses the types of buildings in the new area and the local climate and meteorological changes, and takes into account the energy consumption of various internal and external factors. Based on this, the different climate conditions of different buildings in a year are discussed. The load characteristics of thermal and cold power are analyzed. Finally, a prediction method of thermal and cold load data considering climate and meteorological information, typical structural parameters of buildings, internal and external disturbances is established.
Research and application of key commissioning technologies for new generation of 300Mvar large synchronous condenser
Authors: Li Ming , Zhao Binchao , Liu Yibin , Xing Haiwen , Zhang Ting , Gao Wenlong 
Published: April 2020

Abstract
As the new generation of 300 Mvar large synchronous condensers have gradually been produced and installed in China, research on the commissioning technologies before being formally put into operation is particularly important. This paper mainly takes the view of the difference between synchronous condenser and the traditional large generator especially in the following respects of startup mode, over-excitation performance, and grid-connection mode. The commissioning technologies of electrical system, oil system, chemical system and monitoring system are put forward in detail. Furthermore, innovative achievements such as the optimization design of protection configuration and hot water flow method for checking the water circuit within the stator winding, along with the new type of apparatus for magnetization test of stator core are present. The commissioning technologies have been applied in Yi’nan converter station, which all successfully went into pre-operation after the commissioning work been completed, contributing a lot to the security of regional power grid.
Iterative model coupled with experimental procedures to determine flow rate in a closed natural circulation circuit
Authors: Bello Solomon , Gao Puzhen , Bilal Ashhar , Ahmed Nisrene M , Lin Yuqi 
Published: April 2020

Abstract
A set of simplified iterative model coupled with experimental procedures has been derived to aid in computing the flow rate of a closed rectangular NC Circuit at low pressure/low power steady state condition. The approach involves partitioning the NC loop into different pressure loses segments depending on the associated factor, thereafter the various pressure drops in each segment is determined with applicable mathematical correlations. The iterative model allows for varying of the outlet temperature, at a predetermined Heating Power (Decay Heat) and inlet temperature such that the flow rate is determined when the pressure drops equals to the driving force

(

Δ

P

drive

=
Σ
Δ

P

loss

)

. The model was applied in computing the flow rate of the NC loop considered based on the assigned parameters with results validated with experimental data showing good agreement. Microsoft excel was employed in the computation procedures to allow for simplicity and easy comprehension.
Discussion on the measures of achieving the sub-wet bulb temperature by evaporative cooling
Authors: Bai Yanbin , Yang Lizhong , Zheng Song , Huang Xiang 
Published: April 2020

Abstract
On the basis of introducing the wet-bulb temperature which is lower than the outdoor air temperature and achieved by the indirect-direct evaporative cooling technology, this paper argues that the sub-wet bulb temperature can be used to characterize the air and water-out state parameters of the equipment, and the sub-wet bulb efficiency can be used to characterize the degree to which such equipment can go below the wet-bulb temperature. Moreover, this paper also introduces the typical equipment of China and foreign countries which uses indirect-direct evaporative cooling technology to achieve the sub-wet bulb temperature. The sub-wet bulb efficiency of the foreign indirect-direct evaporative cooling equipment is 106%. According to test results, the sub-wet bulb efficiency of the indirect-direct evaporative cooling air handling units in China is 117%; the sub-wet bulb efficiency of surface pre-cooling evaporative chillers is 115%, and the sub-wet bulb efficiency of tubular pre-cooling evaporative chillers is 120%. Therefore, the analysis results show that the sub-wet bulb temperature and sub-wet bulb efficiency can be used to directly characterize the air/water-out state parameters of such equipment.
Study on deacidification process of waste internal combustion engine oil under the action of ultrasound
Authors: Gong Jing 
Published: April 2020

Abstract
Internal combustion engine oil must be replaced periodically because it deteriorates during use, owing to the formation of oxidized species, particularly organic acids. The oil can be regenerated by removing the acids through alkali washing and neutralization. However the neutralization forms soaps that can cause significant emulsification that decrease the rate of acid removal. We have found that the washing process can be enhanced by using ultrasound, which produces strong shock waves and cavitation that increase the rates of diffusion and mass transfer, leading to an increased rate of deacidification. Our experiments show that a binary base composed of 58 wt% alum and 1.8 wt% diethylamine works well at a deacidification temperature of 50 °C, ultrasonic power of 800W, deacidification reaction time of 18 min. The extent of deacidification can be as high as 88% at 1.5 h.
Research on visualization technology for abrasion of flow guide device in denitrification system based on Tabakoff model
Authors: Ma Lin 
Published: April 2020

Abstract
In order to obtain the abrasion condition of the internal guide device of denitration system reactor intuitively, based on the particle missing model and takeoff wear model, the gas-solid two-phase flow field in SCR reactor is simulated by ANSYS-CFX calculation software, and the fly ash movement track and wear rate distribution of guide plate are visualized. The simulation results show that through the combination of particle missing model and Tabakoff wear model with CFX software, we can directly see the general wear distribution of the guide device in the flue. The wear rate distribution is mainly affected by the particle size of fly ash, and the wear rate value is mainly affected by the mass concentration. By verifying the field flow field test data and checking the wear and ash accumulation of the guide plate, the technical effectiveness is verified, which provides a technical means for the guide device to prevent wear and blockage.
The comparative analysis of two injection modes and recharge capacity estimation for a radial well in the loess area of China
Authors: Zhang Xuezhen , Huo Aidi , Wang Jucui 
Published: April 2020

AbstractThis study is focused on the theoretical substantiation and practical application of the radial well recharge. Two semi-empirical equations were derived for the estimation of the recharge capacity and clogging coefficient of the recharge well, respectively. Two injection modes were applied to analyze the relations between the recharge capacity, water level, and flow rate. Two methods were used to calculate and verify the recharge capacity and clogging coefficient, with a brief analysis of their variation laws. The recharge capacity of the radial well was found to increase with the injection flow, with the following gradual saturation during two injection stages. The recharge capacity increased with the recharge flow, while the clogging coefficient of the second stage was higher than that of the first stage, and exhibited a different variation pattern. The results obtained strongly indicate that the pumping and recharge are hydrological processes, which differ from each other by their physical essence. The available calculation methods based on the pumping theory were found to overestimate the recharge well flow by more than six times. The refined semi-empirical equation provides a more realistic estimation of the recharge capacity of radial wells.
Chainsaw location finding based on travelling of sound wave in air and ground
Authors: Jubjainai Phumpichet , Pathomwong Sittichai , Siripujaka Poom , Chiengmai Na , Chaiboot Anek , Wardkein Paramote 
Published: April 2020

Abstract
Deforestation is a major problem in the world because it affects to temperature and increasing carbon dioxide. In this research, it is therefore proposed that the sound signal inspection of chainsaw which take place from deforest activity and localize the position of deforesting by using the sound signal detection of chainsaw that travels in two mediums are in the air and soil and find the time difference which two waves in both medium travel to the observer or the detector. The correlation operation is used to determine the time difference to calculate the distance between the sound source and the observer and find the direction of the sound source by rotating the microphone to get the most magnitude of sound and take the direction and distance to specify the location of the loggers. Which the proposed system is low complexity and energy-saving and can move easily. From the system test, it was found that the accuracy was 95%.
Fault diagnosis of photovoltaic system based on machine learning model fusion
Authors: Guo Xingke , Na Zhixiong , Ma Dayan , Lu Yudong , Luo Xin 
Published: April 2020

Abstract
With the reduction of non-renewable resources, the energy issues become more and more important and urgent. Distributed photovoltaic power stations not only provides more energy with flexible deployment, but also proposes a possibility of how to fully use the solar energy with a better efficiency. Although a distributed photovoltaic power station has many advantages and great potential, it is not easy to be operated and maintained. In recent years, the applications of machine learning in multiple fields make it possible to do the fault diagnosis of photovoltaic systems more efficiently. This paper designs a full processing system to realize the function of real-time fault diagnosis specially for distributed photovoltaic power stations, which includes the data processing, an online system to give the result of real-time diagnosis, an offline system to retrain models, and a fusion model of several machine learning algorithms. The data processing and performances of different models in this problem are introduced in detail. The fusion model that proposed in this paper acts much better than single models. Hence, the fault diagnosis system could be used in the operation and maintenance of distributed power stations.
An energy management model for isolated microgrid community considering operation flexibility
Authors: Ren Zhichao , Wang Xi , Ye Qiang , Cheng Chao , Li Huaqiang , Zhang Zhiwen 
Published: April 2020

Abstract
The isolated microgrids adjacent to each other form an isolated microgrid community, which can realize optimal resource allocation among microgrids with different source-load characteristics through energy sharing, thereby improving the economical, reliability and renewable energy utilization of regional power system operation. Aiming at the energy management problem of the isolated microgrid community, based on the multi-agent system, a hierarchical energy management architecture of the isolated microgrid community was established. On this basis, the flexibility index is introduced to evaluate the impact of renewable energy output uncertainty on system operation. A multi-objective optimization energy management strategy as well as a community layer energy allocation strategy is constructed. The linearized model is solved by the tolerant lexicographic method. Finally, an isolated microgrid community consisting of four microgrids is taken as an example to verify the effectiveness of the proposed energy management strategy.
Study on sensitivity and selectivity of three-stage current protection in distribution network with distributed generation
Authors: Gong Jing 
Published: April 2020

Abstract
The connection of DG (Distributed Generation) changes the topology of distribution network, which will lead to the change of current detected by relay protection, and the sensitivity and scope of protection will be affected. On the basis of introducing the setting calculation principle of three-stage current protection in distribution network, taking a 10kV distribution network with DG as a model, the influence of DG capacity change on the selectivity and sensitivity of three-stage current protection is discussed in detail when short circuit occurs in different locations such as downstream, adjacent and upstream lines. The corresponding restrictive factors are analyzed and the influence degree of DG access on the original protection is given after comprehensive comparison. It is concluded that comparing different short circuit locations, DG has the most serious impact on the stage-I selectivity of downstream protection when the short circuit occurs at DG downstream line. The conclusions in this paper are of great value to ensure the reliability of power supply of distribution network when a large number of DGs are connected to the grid.
A DC fault identification scheme for multi-terminal VSC-LVDC system based on voltage of current-limiting reactor
Authors: Wang Panbao , Sun Hongmei , Hao Xin , Su Wei , Yuan Dong , Wang Wei , Xu Dianguo 
Published: April 2020

Abstract
The rapid and effective identification of DC faults is one of the key technologies for the development of multi-terminal DC (MTDC) system based on voltage source converter (VSC). The DC system fault current is characterized of high increasing speed and wide influence range. At present, the peak current and the rising speed of the fault current can be limited by current-limiting circuits, which are serially connected at both ends of the DC line. In this paper, the DC fault characteristics of a three-terminal DC system with DC line current-limiting reactors are analysed. On this basis, a fast identification method for DC faults in MTDC system according to the voltage across the line current-limiting reactor is proposed. The proposed scheme can quickly identify the fault location, the fault type and the fault pole. Finally, the effectiveness of the proposed fault detection scheme is verified by simulations. The simulation results show that the proposed method is still effective when the fault resistance and fault distance change, and is able to realize the rapid and accurate detection of DC faults.
Health evaluation of urban water supply pipe network using the Bayesian method based on triangular fuzzy number optimization
Authors: Ding Xiangyi , Liu Siran , Shi Xiaolin , Chu Junying , Guo Xinlei 
Published: April 2020

Abstract
With the rapid increase of urbanization level in China, the accidents related to urban water supply pipe network occurred frequently due to the impacts of pipeline aging, environmental change and human factors, thus the health evaluation of urban water supply network has become one of the hot topics in recent years. Related researches mostly refer to qualitative and static analysis, some quantitative studies consider the influence of only one aspect on the status of water supply pipe network such as hydraulic, water quality and static structure, and cannot objectively reflect the health status of pipe network due to neglecting or simplifying the influence of internal hydraulic condition on the health of the pipe network. Comprehensively considering the influencing factors and the hydraulic mechanism during the operation process of pipe network, this study constructs a health evaluation index system for the water supply pipe network, and introduces the triangular fuzzy number theory into the traditional Bayesian water supply network health status evaluation model taking the uncertainty of model structure and data into account. Through applying the method to Yunhe county of Zhejiang Province China, some suggestions for the optimization and transformation of the regional water supply network are proposed, which can provide a basis for ensuring the safety of regional water supply and scientifically determining the renewal sequence of the pipe network.
Differentiation of digestion method for heavy metals in river sediments based on organic matter gradients
Authors: Liu Jinbao , Shen Qiu , Wei Fang , Guo Zhenni , Tian Yingjie 
Published: April 2020

Abstract
Heavy metal detection in river sediments is critical in evaluating heavy metal pollution levels, risk and control in these matrices. Most of existing detection methods have the disadvantage of low recovery rate and high total acid consumption. Due to continuous accumulation of metal and relative high content of organics in river sediments, this paper focused on studying differentiated digestion method of heavy metals based on organics gradient grading. Surface river sediment samples were collected from 26 different rivers and lakes within the Qiantang River basin (e.g. Hangzhou and Jiaxing). Organic matter content in these samples were tested and these samples were divided into 8 groups according to content of organic matter. This was followed by testing the effects of hydrochloric acid, nitric acid and hydrofluoric acid on the digestion of heavy metals (Cu, Zn and Ni). The optimum digestion system of heavy metals in river sediments based on organic matter gradients was established. Results demonstrated that digestion system can achieve high recovery rate (90%∼110%) and an average dectection accuracy, while total acid consumption is about 10.54 mL, which is less than that of the Chinese standard digestion method (19mL). This means that the digestion system proposed in this paper is environmentally friendly.
Birds protection and safety research of transmission lines
Authors: Liu Hui , Zhou Chao , Shen Qinghe , Yao Jinxia , Liu Chuanbin , Qi Zhao 
Published: April 2020

Abstract
Bird related fault of transmission line has become the main factor of line trip. The rule on bird related fault of transmission line is shown in this paper which contains monthly distribution, monthly distribution, reasons of faults and the state of reclosure, the species of related birds, time and season of the faults, environment around the towers, type of towers and insulators and flashover and burns characteristics of the faults. With regard to problems of bird related faults, several anti-bird measures and its characteristics are studied. It is suggested that anti-bird devices should be installed above jumper wires to eliminate the blind area of bird repellent.
Groundwater assessment based on analytic hierarchy process and the normal cloud model in Weinan, China
Authors: Qu Wengang , Xu Panpan , Qian Hui , Zhang Qiying 
Published: April 2020

Abstract
Groundwater quality is facing a grim challenge due to the development of Weinan city. A multi-index comprehensive evaluation method—analytic hierarchy process and normal cloud model are proposed to evaluate the groundwater quality of Weinan city. Seven parameters including TH (total hardness), TDS (total dissolved solids), SO4
2-, Cl−, COD, NO2
−, Mn were selected to characterize the groundwater quality. The results show that the groundwater quality level of W6 and B557 are excellent water quality (I), H32, W15, W23, and W14 are good water quality (II), only B24 is medium or average water quality (III). Compared with other methods, the results obtained by the proposed method are in good agreement with the NI method but far from SFI method. This study confirms the suitability of the Analytic hierarchy process and Normal cloud model method in groundwater quality evaluation in Weinan city, and provides a reasonable basis for decision-makers of groundwater protection and utilization in Weinan city.
Trend and abrupt analysis of Dongting Lake water level and its driving forces using Mann-Kendall approach
Authors: Dai Lingquan , Liu Haibo , Li Wei , Tang Zhengyang 
Published: April 2020

Abstract
In order to quantitatively describe the evolution trend of Dongting Lake water level and its driving forces, the Mann-Kendall approach is used to determine the lake water level and its driving forces, including the discharge of the Yangtze River at Yichang hydrological station, three outlets, and four rivers. The results show that the annual runoff and the runoff from September to October of the Yangtze River, the annual runoff of the three outlets have a significant downward trend, especially after the impoundment of the large reservoirs on the middle and upper reaches of Yangtze River. The Yangtze River discharge has a sudden change during the impoundment period, while the annual runoff and the runoff from September to October of the four rivers showed an insignificant decrease trend. The lake water level at Chenglingji decreased during the impoundment period of the large reservoirs slowed down, especially in September and October, so we can see that the reservoir impoundment is an important factor that decreasing the water level of Dongting Lake.