bluuebunny/crossref_metadata_2025 huggingface dataset:
The basic principle of enhancing oil recovery technology in heavy oil reservoirs
Authors: Sun Jianghe , Zhang Fusheng , Li Xuening , Shan Dalong , Liu Guoliang , Zhu Zhuoyan
Published: April 2020

Due to the heterogeneity of heavy oil reservoirs and the high viscosity of heavy oil, the recovery rate of heavy oil reservoirs is much lower than that of conventional reservoirs. So increasing the recovery rate of heavy oil reservoirs is of great significance to the goal of improving the technical level of heavy oil development proposed by the National Energy Plan. This paper outlines several commonly used techniques for improving the recovery of heavy oil reservoirs, including steam flooding, hot water flooding, polymer flooding, surfactant flooding, microbial flooding, foam flooding, ultrasonic viscosity reduction technology, etc. And briefly explains the basic principles. The internal causes of the problem are analyzed, and several focal points for improving the recovery of heavy oil that should be paid attention to are put forward.
Numerical simulation model adaptability research for fractured reservoir
Authors: Xie Kun , Li Fangfang , Li Depeng , Zhang Qiang , Chen Xueli
Published: April 2020

Characterization and forecasting in fractured reservoirs is one of the most challenging topics in oil and gas industry. Due to significant difference of fluid flow mechanism in fracture and in matrix, managing such reservoirs requires construction of representative reservoir models. Dual porosity & dual permeability model (DPDP) is the first choice of fractured reservoirs, but history matching and plan prediction of this model facing poor convergence and long running time. Other models like dual porosity & single permeability model (DPSP), single porosity & single permeability model (SPSP) sometimes can replace DPDP and can be able to improve convergence and save calculation time, but lack of model equivalence criterion. In this study, 84 cases of 4 reservoir models has been built and simulated to study the equivalence criterion. Permeability difference and oil viscosity are considered to be the main influencing factors affecting model equivalence. With the application of the equivalence criterion, weak convergence and time consuming of fractured reservoir simulation can be improved.
Influence of water resources in Xinjiang on exploitation of coal resources and measures for their use
Authors: Cheng Chunyan , Zhang Yan , Yan Qiang , Zhou Fengying , Gao Tianming , Hou Baojun , Zhang Songtao , Song Mei , Wang Qingwei
Published: April 2020

Xinjiang is rich in coal resources, but the extremely shortage of water resource in some regions has significant impact on coal exploitation. Water is required in coal exploitation, as well as cleaning, utilization and upgrading of coal, so the shortage of water resource is impacting the fate of coal directly. Xinjiang area is the 14th coal base of our country, a foothold of the strategy of West-Development in China, and a support point of national strategic layout of the Belt and Road Initiative. If the problem of coal and water is solved, the problem of energy safety and nationality will be solved. Based on the comprehensive analysis of coal geological conditions and water resources conditions in Xinjiang, we have studied the spatial distribution relationship between coal resources and water resources in this paper, and find that the whole water resource is short in regions of Xinjiang with rich coal resource. In this paper, some feasible suggestions have been put forward to solve the problem of asymmetric distribution of water and coal resources as the key problem at present, in order to provide reference for departments of resource development and planning.
Design of backstepping controller for T-type network inverter
Authors: Gao Guanghui , Zeng Jiaqi , Han Jianding , Lei Xiaoben
Published: April 2020

In the process of power conversion of new energy generation, complex two-stage converter is needed. T-type network inverter is a kind of transformer that can realize three-phase power output from two single-phase output inverters. Functional Topology, the purpose of this paper is to design the circuit topology and controller so that the inverter output voltage meets the power supply requirements. First, the DC power input circuit and transformer structure are designed according to the principle of voltage vector synthesis. Then the controller is designed by state space average modeling method and backstep method. Finally, the system model is built by Matlab/Simulink simulation software. The conversion of 27V DC power to 220V / 50Hz three-phase power for market power supply verified The effectiveness of The design content of this paper.
Impacts of electrode structure on plasma discharge in pre-breakdown period for water environment treatment
Authors: Huang Yan , Zeng Xinwu
Published: April 2020

Since the liquid discharge problem has been incorporated into the line of sight, many scholars have done a lot of research on it. In this paper, experiments on the pre-breakdown period in underwater plasma discharge were carried out. Among the parameters of underwater plasma discharge, the electrode structure is firstly taken account by virtue of its intuitive, easy-to-process, and diversity. With the refinement of the application of liquid discharge in liquid-electric processing, research on the effect of electrode structure on underwater plasma discharge is deepening. In this paper, two sets of electrode groups were proposed in a pioneering manner through the theoretical analysis and precise control of the experimental parameters. Based on the experimental results, rigorous and reliable analysis and summary were demonstrated. The conclusions of this paper would be helpful for water environmental treatment.
Denitration performance of CuO/γ-Al2O3catalysts modified by CeO2
Authors: Zhang Qilong , Dong Yong , Cui Lin , Zhang Liqiang , Wang Peng
Published: April 2020

CuO-CeO2/γ-Al2O3catalysts with different CeO2loadings were synthesized by wet impregnation method. Selective catalytic reduction (SCR) of NO over the two kinds of catalysts was carried out in a fixed bed reactor. CuO-CeO2/γ-Al2O3catalysts reached NO conversion efficiency 65% at 150 °C and maintained over 80% at 200-400 °C, The maximum efficiency is stably reached at 300 °C. CuO-CeO2/γ-Al2O3catalysts showed wider temperature range than that of the CuO/γ-Al2O3. NH3-TPD tests were carried out to study the adsorption and oxidation behavior of NH3over CuO-CeO2/γ-Al2O3catalysts with different CeO2loadings in the presence of oxygen. The NH3adsorption and activation performance were modified attributing to the modification of the Surface acidity of the CuO-CeO2/γ-Al2O3catalysts. The mass transfer was improved due to the promotion of the pore numbers in 8-50, 50-200μm which was another NO conversion promotion factor. Surface acidity and the pore volume decreased obviously as CeO2overloaded in CuO-CeO2/γ-Al2O3, with a negative influence of NH3adsorption and oxidation performance. It is considered to be the main factor of the NO conversion efficiency decreased.
Radioactivity measurement in glacier and Polar ice-caps: An overview
Authors: Ayoub Anuor. A.T , Song Yushou
Published: April 2020

Glacier is an extended mass of ice formed by snow falling and accumulating over the years and moving very slowly either by descending from high mountains, as in valley glaciers or by moving out of accumulation centers, as in glaciers on the continent. Glaciers are a significant source of potable water and plant irrigation, any contamination of this significant source in glaciers due to radionuclides may affect freshwater supplies and livelihoods. It is well known that exposure to ionizing radiation could lead to health hazards and harm to the environment. Therefore, awareness of the distribution and concentrations of natural and artificial radionuclides in the glacier region is crucial, and that is why it provides and clarifies helpful information about radionuclide pollution in the environment. This evaluation gives insights into the overview of the radioactivity of natural and artificial radionuclides in the glacier region (Arctic and Antarctica). These information are crucial for predicting the effects of radionuclide distribution and transport in ecosystems, and can also be an indication of the effects of external human activities in the cold regions.
The Radiation properties of Barite-xylem shielding board
Authors: Chen Tzong-Jer
Published: April 2020

Radiation is used in a variety of medical and scientific fields but poses potential danger to the human body. Hospital medical x-ray technicians traditionally use lead shielding materials to absorb radiation. However, lead has environmental disadvantages, with high toxicity to humans. Barite, a heavy-weight material, is added into concrete and bonded with xylem fiber, forming a shielding board as a replacement for lead. The xylem fiber barite shielding board (XFBSB) development and shielding properties are investigated in this report. XFBSB is designed for diagnostic medical x-ray shielding. It may be applied as shielding in walls and ceilings, doors and movable wall partitions. The physical properties of XFBSB are 14 mm in thickness with density ⩾ 2.0 g/cm3. This board was irradiated using a standard x-ray tube (Type MXR 320/Comet Y. TU 320 G03, TÜV NORD Sys Tec GmbH & Co. KG, German) with 70 kV, 100 kV and 150 kV Voltages respectively. The current of this standard x-ray tube is 22.5 mA, respectively. From the measured ambient dose equivalent H*(10), the attenuation factor F=H*(10) with board/H*(10) without board was calculated. For comparison, lead boards of 1, 2, 3, 4 and 6 mm thicknesses were irradiated under equal conditions with the attenuation factors F fitted for the different lead board thicknesses. The boards are proven to ⩾ 1mm lead equivalent in all irradiation energies. The XFBSB can substitute for lead shielding for photon energies around diagnostic medical areas. This board provides adequate shielding, is non-toxic, fire proof, easily installed and low cost.
Simulation and experiment of NOX concentration detection in diesel engine exhaust gas
Authors: Liu Xiaonan , Guo Ao , He Yanbo , Mu Yanlong , Yang Xiaotao
Published: April 2020

As people pay more attention to environmental problem, the issue of how to measure and reduce pollutant of the exhaust of ships were put on the agenda. To realize the detection of NOX(nitrogen oxides) content in the marine diesel exhaust emissions, the SIMULINK of MATLAB software with superior data processing capabilities was selected in this paper to enable the detection of NOX content by direct absorption measurement based on laser absorption spectroscopy (TDLAS).). The absolute error of the simulation model was less than 0.15%, and the maximum relative error didn’t exceed 1.25%. At the same time, the simulation error of the model was less than 5.0% compared with the test results of the AVL emission meter. The results had shown that the model can accurately simulate the detection process of nitrogen oxides of diesel exhaust emissions. It not only provides reference data onto people to detect harmful gases in ships but also provides valuable experience in optimizing diesel engines control strategies.
The distribution of combustible ice and the status of exploitation
Authors: Wang Ruihe , Guo Lei
Published: April 2020

The distribution of combustible ice in the world is investigated. The characteristics of different mining methods are clearly defined by the analysis of the successful cases of the development of combustible ice in the United States, Japan, Russia, Canada and India. The distribution rules and the historical process of the development of the combustible ice in China are introduced, the discovery of the combustible ice in the South China sea is analyzed. The analysis of ice production technology, the mining methods, applicable reservoirs and existing problems of combustible ice are expounded. The significance of combustible ice as a new energy to alleviate energy crisis is pointed out.
Mathematical modelling and operation parameters analysis of proton exchange membrane fuel cell
Authors: Zhu Lingkun , Yu Qiang , Huang Ying , Guan Jingyu , Wang Yupeng , Yan Yanfei
Published: April 2020

The fuel cell is a device which can convert chemical energy from fuel into electrical and thermal energy directly. It has advantages like high power density, fast start-up and high conversion efficiency. Its prospects of application in transportation, fixed power supply and standby power generation are great. Fuel cell is a dynamic complex system with multi-phase, multi-scale and multi-physical fields. Based on the working mechanism of fuel cell, this paper establishes a mathematical model to simulate the electrochemical reaction, material and energy transfer process in fuel cell. The parameters such as temperature, pressure, concentration, current and potential, which are difficult to measure, are visualized to deepen the transfer and counter-reaction in fuel cell. In order to provide important scientific basis for the optimal design and system control of the stack, the mechanism should be understood and the optimum reaction conditions should be found.
Optimization modelling of HCMC-STATCOMs for offshore wind power based on PSCAD
Authors: Dou Fei , Wang Weiyuan , Xia Kai , Yu Xuan , Wang Lijun , Xu Yiqing
Published: April 2020

Under normal circumstances, the voltage fluctuation of the wind farm’s grid connection point is mainly caused by the volatility of wind power output. In recent years, with the clustering development of offshore wind power, the voltage fluctuation brought by the output fluctuation of wind power is becoming more and more notable. The main method of improving the reactive voltage problem of wind farms is to add more static and dynamic reactive power compensation devices. Hybrid cascaded multilevel converter STATCOMs (HCMC-STATCOMs) don’t need transformers to increase the device capacity and decrease the harmonics on the output voltage, which is effective in reducing the device cost and volume. This paper firstly introduces the topology and operation principles of an HCMC-STATCOM and then carries out a comparative study on HCMC-STATCOMs and traditional cascaded STATCOMs. Finally PSCAD/EMTDC is applied to model and simulate HCMC-STATCOMs. The simulation result shows that the reactive power of HCMC-STATCOMs can accurately vary according to the system’s demand on reactive power. This means that HCMC-STATCOMs have good dynamic performance and the harmonic contents in the output phase voltage and AC current are quite small. As a dynamic reactive power compensation device, HCMC-STATCOM can be adjusted in real time according to the system’s reactive power requirements, and has the advantages of small volume and low cost. The simulation results show that the properties of HCMC-STATCOMs are advantageous for the operation and control of the system and applicable for the dynamic reactive power configuration of offshore wind power.
Vessel hydrostatic test duration analysis in prssurized water reactor nuclear power plant overhaul
Authors: Zhang Zhenguo
Published: April 2020

The vessel hydrostatic test is one of the important test means of the nuclear vessel sealing and pressure resistance, and it is an important project in the plant overhaul. Because the vessel hydrostatic test involves many key systems and key vessels, and it belongs to the critical path or time critical path in plant overhaul, how to estimate the vessel hydrostatic test duration in overhaul is necessary. This paper discusses the actual hydrostatic test time of different vessels in pressurized water reactor nuclear power plant overhaul, and divides the test time into three categories, that is long (more than 6 days), medium (3 to 6 days), and short time duration for a project (less than 3 days). This paper also discusses the key factors that influence the vessel hydrostatic test duration and puts forward the optimization suggestions of vessel hydrostatic test duration.
Natural circulation systems in nuclear reactors: advantages and challenges
Authors: Ahmed Nisrene M. , Gao Puzhen , Bello Solomon
Published: April 2020

Following the Fukushima disaster in Japan in March 2011, a number of questions and doubts about the safety of nuclear reactors have been raised globally and many nations have begun revising and improving the nuclear installations. Natural circulation plays a major role in nuclear accident. This significance of the natural circulation-based systems led us to study the natural circulation phenomena for better understanding and in order to ensure the safety and efficiency of natural circulation systems. This review focuses on the advantages and challenges of natural circulation systems.
A NB-IoT based intelligent combiner box for PV arrays integrated with short-term power prediction using extreme learning machine and similar days
Authors: Zhang Caigui , Chen Zhicong , Wu Lijun , Cheng Shuying , Lin Peijie
Published: April 2020

The grid-connected photovoltaic (PV) power stations are instability and volatility due to meteorological factors. A way to improve this problem is PV power forecasting. This paper proposed an improved short-term PV power prediction model that combines an extreme learning machine (ELM) neural network and similar day method. Firstly, a narrow-band Internet of Things (NB-IoT) intelligent combiner box data monitoring system is designed to collect multivariate meteorological factors and original PV output power datasets in different seasons. Secondly, the corresponding training set is selected according to the season type of the forecast day, and the Euclidean distance (ED) between the training set and the forecasting day is calculated, and the M-day with a small Euclidean distance is selected. Then, the N-day similar day data is divided among the M days as the new training set input, and the P-day optimal similar day data and the multivariate meteorological of the prediction day are divided as test set inputs. Finally, the ELM neural network prediction model is used to predict the output power of the predicted day. The experimental results show that the proposed method has the highest prediction accuracy in contrast to other two prediction models.
Measurement and analysis of the in-cylinder process of a LNG engine under transient operations
Authors: Xia Yan , Liu Jingping , Song Rongfeng , Zhang Shijia , Fan Mingxiang
Published: April 2020

Parameters reflecting the in-cylinder process in a turbocharged, LNG fuelled, spark ignited engine, such as the intake manifold pressure, air/fuel ratio (AFR), fuel mass flow-rate, as well as the dynamic in-cylinder pressure traces, are measured cycle-by-cycle for a series of transient operations via external air injection into the engine intake system. During the transient load step process, the engine experiences not only abrupt change of boost pressure and AFR, but also rapid engine load change. The changes in the in-cylinder combustion process during the transient operations, which were rarely revealed before, are illustrated with the rate of heat release (ROHR) characteristics cycle-by-cycle. The influences on the combustion characteristics under the transient operation conditions, of the operational parameters, such as AFR, air and fuel flow, boost pressure, etc. are examined and discussed. Existence of abnormal combustion such as late combustion, misfiring and severe variation of IMEP, etc. are pointed out. The possible causes of those abnormal combustion phenomena are also analyzed. The in-cylinder process detection method presented in this paper is universal and can be extended to other similar applications.
Research on doubly-fed wind power system based on MATLAB/Simulink software
Authors: Guo Yaqin
Published: April 2020

With wind randomness and burstiness, output power of wind turbine will be fluctuated, and fluctuating power affected the operation of power grid in the grid-connected. Therefore, it is necessary to research wind power system. The structure and principle of Doubly-fed wind power system are introduced in the paper, by analysing the principle, we build simulation model of Doubly-fed wind power system using MATLAB/Simulink software. In order to test the performance of the model, the phase-voltage, phase-current and active power of the system are tested under three status, which are steady-state operation, different wind speed and three-phase short circuit. The experimental results show that Doubly-fed wind power system has strong anti-interference and good safety.
The study for MPPT of photovoltaic system based on terminal sliding mode control method
Authors: Zheng Dandan , Li Jian , Wu Wei , Yu Hui , Du Jiawei , Sun Wenbing , Xiao Shiyi , Shao Zhuxing
Published: April 2020

Aiming at the problem of the Maximum Power Point Tracking (MPPT) of PV system, based on the requirements of improving the tracking speed and reduce the steady-state oscillation, a terminal sliding mode control method is proposed to complete MPPT control in this paper. Mathematical model of the PV module is realized by four parameters with standard condition. Unlike traditional methods, it is proposed that the tracking current and power reference at the maximum power point at arbitrary conditions can be obtained directly from the established model. It is simple and can avoid the tracking error. In this paper, we tracked the outputs of the PV module under different conditions and compared the proposed method with the Incremental Conductance (INC) algorithm, the results show that the proposed control method can enhance the track speed and accuracy, decrease the steady-state oscillation and improve the efficiency of PV system.
Analysis method of the influence of electric bus optimal charging on the renewable energy power consumption
Authors: Tian Xu , Wang Wei , Liu Fei , Liang Guoyong , Zhang Wei , Wang Shibin , Fu Yanan
Published: April 2020

To analyze the influence of the optimal charging of electric buses on the consumption of power generated from renewable energy sources, an optimal charging model with the electricity price revision is proposed. The revision helps to promote consistency between the charging load and renewable energy power. Then the analysis of the influence of electric bus optimal charging on the renewable energy power consumption can be achieved. Based on the revised electricity price, a 0-1 integer linear programming model for the optimal charging of electric buses is established, aiming to derive the lowest charging cost. The method takes into account the demand of buses’ drive range, continuous charging and the number of charging piles.
Mathematical modelling of gasification processes of the biofuel in the conditions of chemical equilibrium
Authors: Pavlenko Anatoliy , Slowak Anna Maria
Published: April 2020

The article presents the results of experimental studies of the process of biomass heat treatment. The method of mathematical modeling of the biomass gasification process is improved on the basis of the thermodynamic model of Gibbs free energy minimization In most countries, their energy strategies involve an increase in the share of renewable energy sources, including using a sufficiently large biomass potential. The solution of the Lagrangian function made it possible to determine the composition of the generator gas and the efficiency of the process. The accuracy of the proposed mathematical is estimated. The obtained results of the work can be used to determine the optimal conditions for gasification in the development of biomass gasification technologies.
Typical fault analysis and preventive measures of 110kV XLPE cable fully prefabricated dry terminal
Authors: Duan Yubing , Zhang Hao , Hu Xiaoli , Liu Rong , Liu Hui , Liu Chuanbin
Published: April 2020

With XLPE cables are widely put into operation in the city underground power system, it is more and more important of the stability of 110kV cable lines. The prefabricated dry terminal due to lack of firmly fixed and other shortcomings, Cable breakdown faults are easy. In recent years, several terminal breakdown prefabricated dry cable typical case in shandong power network, a comprehensive analysis of the breakdown faults reason, combined with the operation experience, put forward the new 110kV cable line prefabricated dry terminal platform installed in the transport line, the new 110kV cable line prefabricated dry terminal comprehensive inspection, strengthen the infrared temperature measurement of charged detection, transformation timely preventive measures. Through the development of 110kV cable line full prefabricated dry terminal breakdown prevention measures, it can effectively reduce the probability of the faults and improve the reliability of high voltage cable line operation.
DC/DC half-bridge SST based on energy router
Authors: Chen Yang , Li Pengfei , Li Zichen , Zhang Yanchi , Xie Da
Published: April 2020

In this paper, a DC/DC half-bridge SST (Solid state transform) based on energy router is proposed. The structure mainly includes high-frequency transformer circuit, half-bridge circuit and control circuit. The DC side is converted to a high frequency AC signal through a half-bridge circuit. Then the high-frequency transformer circuit transmits the AC signal to the secondary side, and the secondary side is connected to the same half-bridge circuit for rectification to make electrical energy output in the form of DC. The whole circuit adopts symmetrical structure, which is beneficial to the bidirectional flow of energy. The simulation results verify the correctness and feasibility of the design scheme.
Simulation and contrast study on flywheel energy storage control strategy for dynamic stabilization of power fluctuation in power grid
Authors: Zhou Feng , Liu Mingliang , Jiang Peng , Xu Mingyu , Hao Wenbo , Wang Bing , Wang Luxin
Published: April 2020

Flywheel Energy Storage System can not only effectively reduce the impact of energy fluctuation on the power grid, but also fully improve the utilization of distributed energy system because of its characteristics of energy storage and rapid charging. In this study, permanent magnet brushless DC motor is selected as flywheel motor for wind power system. The mathematical model of flywheel energy storage system in rectangular coordinate system is established. The double closed-loop simulation model of speed and current of flywheel energy storage system is built by using MATLAB/Simulink. In order to improve the control performance of flywheel energy storage system, three different control strategies, PID control, sliding mode variable structure control and ADRC control, were used to simulate the charging and discharging dynamic process of FESS. Considering the particularity of flywheel energy storage system as a limited energy storage unit, the controller parameters of three traditional control modes are adjusted effectively on the premise of keeping the parameters of the flywheel motor unchanged. The simulation results are compared from rotation rate and torque, and the advantages and disadvantages of three control strategies and the dynamic performance of flywheel energy storage system under different control strategies are analyzed.
Data transmission of cyber physical power system
Authors: Hu Yishuang , Jiang Zhengwei , Sun Yikai , Ding Yi , Xu Chenbo , Jin Xueqi
Published: April 2020

Aiming at monitoring the behaviour of power system to make it work correctly and better, cyber physical power system (CPPS) was introduced. However, due to the high integration of cyber system, the complexity of power system is greatly enhanced, which puts forward higher requirements for the reliable and safe operation of CPPS. Moreover, when the cyber system is under attack, abnormal information flow may lead to abnormal energy flow. Therefore, this paper proposes a data transmission mechanism to analyse the information flow among CPPS. A data transmission optimization model based on the transmission matrix is constructed. The data transmission from the cyber system to the power system is quantified by the model. The practicability of the proposed data transmission mechanism is given by numerous cases.
Robust coordinated capacity allocation for wind generation and energy storage in power systems
Authors: Wang Xiaobin , Fan Sheng , Wang Gang
Published: April 2020

Aiming at locating and sizing of wind generation and energy storage in power system planning stage simultaneously, a bi-level optimization model is constructed. The first stage is mainly used to allocate the capacity of wind farms considering the total cost of establishment, operation and maintenance from both wind generation and energy storage. The second stage is applied for allocating energy storage to address the violations of wind generation. Robust optimization theory and genetic algorithm are used to solve the model. The effectiveness of the proposed model is validated by the Garver’s 6-bus system.
Control strategy of grid-connected inverter droop based on GMPPT method
Authors: Zhang Xuyang , Teng Jun , Zhang Pengqiao , Jia Minglei , Yu Cong , Sun Yifei , Sun Jia , Ma Pengran , Zhou Bowen , Cao Nanjun , Liu Hengyu , Yu Zhiwei
Published: April 2020

The conductance increment method (INC) can be quickly and accurately stabilized at the maximum power point (MPP) but easily falls into the local extreme point (LMPP) in the shadow environment. Considering the particle swarm optimization (PSO) can quickly achieve global optimal search but the number of iterations is too large when local convergence, leading to fluctuation and energy loss. Therefore, a global maximum power point tracking (GMPPT) is proposed, which combined the PSO and INC and improved them. In this paper, the research object is the single-phase two-stage PV grid-connected system. The GMPPT needs a stable DC voltage (Udc) to track accurately and the grid-connected inverter needs a stable Udc in order to ensure the quality of grid power. Therefore, the goal of the inverter control is to achieve the combination of GMPPT and grid-connected control. Based on the characteristics of PV power generation, a PV grid-connected droop control strategy based on GMPPT is proposed, which realizes the stability of Udc and the output of MPP and meets grid-connected requirements. Finally, the simulation model of PV grid-connected system based on Matlab/Simulink software is used to verify the effectiveness of the proposed control strategy.
Water quality assessment using comprehensive water quality index and modified Nemerow index method: A case study of Jinghui Canal, North China
Authors: Zhang Yuting , Hou Kai , Qian Hui
Published: April 2020

Groundwater is an essential part of water resources for human survival in irrigation regions. In this study, water quality of jinghui canal irrigation area were assessed using the comprehensive water quality index method (CWQI), normal Nemerow index assessment method (NNI) and modified Nemerow index assessment method (MNI). 47 groundwater samples were collected from unconfined aquifers through shallow well during November 2009. The results showed that groundwater quality in the area was poor due to the industrial and agricultural activities. Most of the groundwater samples were identified as Grade IV and Grade V by the comprehensive water quality index method. While majority of groundwater samples were assessed as Grade IV by both NNI and MNI. Besides, the water quality assessed by MNI was better than NNI and NNI was better than CWQI, which was caused by parameter value and weight value, so we should not only stick to a certain assessment method, but also need to comprehensively consider the purpose of evaluation.
Gas-water two-phase discharge phenomenon in PEF chamber for water treatment
Authors: Wang Zhiyuan , Zhang Ruobing , Chen Zhihao
Published: April 2020

Pulsed Electric Field treatment is a critical technology in waste water treatment and sterilization. However, the discharge of the treatment chamber that causes the damage of pulse generators is one of the main technical issues of its applications. Bubbles under water are the most vulnerable sections and could cause breakdown since it is too difficult to generate discharge in the bulk of water under microsecond-pulse and relatively low electric field(<70kV/cm). Uniform discharging images of gas bubbles under water are captured. The influence of γ approach on breakdown in short gas gap (under 1cm) with water electrode under atmospheric pressure is confirmed. The influence of conductivity of aqueous solution and the repetitive frequency of voltage pulses is discussed. It can be confirmed that the breakdown phenomenon of the PEF treatment chamber is mainly caused by air bubbles, which are generated by Joule heat process as well as cavitation and then discharge under the metal cathode. This work presents vital references for improving the design of PEF treatment chambers.
Multivariate analysis of phytoplankton community structure in Changli Gold Coast National Nature Reserve of Hebei Province in Spring, 2019
Authors: Guo Xiaqing , Yu Yang , Zhu Haoran , Zhao Xinggui , Liu Xianbin
Published: April 2020

In order to research the characteristics of phytoplankton community structure in Changli Gold Coast National Nature Reserve, China, 14 survey stations were set up in this area in May 2019. The basic characteristics of phytoplankton community composition, cell abundance and community diversity were analyzed, and the Multi-Dimensional Scaling (MDS) was used to divide the structure of phytoplankton community. The results showed that a total of 30 species of phytoplankton were identified in this area, mainly diatoms, and the main ecological types were temperate inshore wide temperature and wide salt species. The average cell abundance of phytoplankton in May was 54.38×104 cells/m3, and the main dominant species were Nitzschia sp., Skeletonema costatum and Noctiluca scientillans. The average value of Shannon-Wiener index was 2.26, The average value of evenness index was 0.75. The average of richness index was 0.73. The phytoplankton divided into 6 zones with significant differences by CLUSTER Analysis (P<0.001).
Analysis of Suaeda heteroptera cover change and its hydrology driving factors in the Liao River Estuary wetlands, China
Authors: Wang Yini , Ji Yongpeng , Sun Zhen , Li Jin , Zhang Mingliang , Wu Guanglu
Published: April 2020

Suaeda heteroptera (S. heteroptera) is the most common indicator plant of solonchak in coastal wetlands of the Liao River Estuary, the influence of meteorology, hydrology environment on vegetation distribution is of growing interest. With the help of satellite remote sensing (RS) technology and geographic information system (GIS), we investigated the spatial-temporal distribution and area change of S. heteroptera in the wetlands of the Liao River Estuary from 1997 to 2016, and the identification of the main driving mechanisms in the S. heteroptera evolution was analyzed in this coastal wetland. The SPSS Statistics 22 software was used to calculate the correlation coefficients between total area of S. heteroptera and each driving factor based on available long-term (1997-2016) and medium-term (2007-2016) data. Correlation analysis results indicated that the change in S. heteroptera coverage had insignificant correlations (correlation coefficients r=−0.241, r=−0.188 and r=−0.269) with annual mean temperature, precipitation, and sunshine duration, respectively. The results also showed that the growth of S. heteroptera was extremely relevant to runoff from the Liao River from April to June (r=0.889) over the last 10 years. This study revealed that some potential factors, such as river discharge may be related to the large-scale degeneration of S. heteroptera in Liao River Estuary wetlands.
Simulation investigation of effect on nanoparticles discharging pattern of a car caused by a following one on a typical city road
Authors: Hao Feilin , Shen Mingwei
Published: April 2020

Vehicle emission is supposed to contribute a great part to the urban air pollution in China, and many relative studies were carried out on a macro base at “city valley” scale. This article, on the “micro” individual scale otherwise, attempts to explore the fine particles’ spreading process after leaving the tailpipe of a typical car equipped with the inner-combustion engine in city main road through 3D CFD simulation. two geometries of typical cars driving in typical city road were built up with detailed structures: one is one car driving on the main city street and the other is two cars, one followed the former established car, all with a driving speed of 40 km/h. Eulerian multiphase model is adopted to describe the dynamics of the multiphase: air, particles in 10nm diameter, and particles in 70nm diameter. The simulation results show that the diffusion process of 70nm particles is mainly governed by gravity, more than 80% of which concentrate within the region behind the car with a volume of 4.0m in length, 3.0m in height, and 2.0m in horizontal width along the centreline of tailpipe, while the 10nm particles exhibit a wider and more random distribution pattern, it spreads throughout the simulation volume with noticeable volume fraction: above, beneath, and behind the driving car, the high volume fraction regions mostly occur within a volume of 12.0m in length, 4.0m in height, and 4.0m in width associated with the tailpipe. The followed car causes a “compressing and lifting” effect, it is found that the high-volume fraction regions of particles are compressed to, in one hand, move around to the bodies of the two cars, and the other hand move towards the sides of the road. The particles in 70nm diameter are less affected by the followed car than that 10nm, especially the lifting effect of high-volume fraction regions of 10nm particles. This suggests some nonconventional management measures should be taken to control the urban air pollution of vehicles.
Research progress on migration and transformation model of heavy metal pollutants
Authors: Liu Chuan , Ma Xiaoye , Huang Xu , Cai Mingxuan , Hei Liang
Published: April 2020

With the continuous development of the economy, the pollution of heavy metals to the environment is becoming more and more serious. It is more and more urgent to study the migration and transformation of heavy metals. This paper reviews the classification of heavy metal migration and transformation models, which can be divided into: chemical thermodynamic model, chemical reaction kinetics model, migration and transformation kinetic model (overall model, phase separation model, empirical model), and introduces the applications of the model in different aspects.
Water quality simulation of sewer plant discharge considering long-term and short-term conditions
Authors: Wang Junmin , Fu Lei , You Aiju
Published: April 2020

The development of economy and society in China leads to a huge amount of wastewater discharge, which becomes a serious problem in most of Chinese cities. Therefore, the construction of sewer plant is more popular than before in lots of these cities. The wastewater discharge from the plant is then considered as a point source in most of the important rivers and channels. In this study, a typical wastewater treatment plant is introduced, a monitoring experiment is designed and executed to observe current river status. Additionally, a two-dimensional model is established to predict the water quality downstream of the plant. It is confirmed that the water quality will not significantly deteriorate, however, systematic control of wastewater discharge and protect of current river environment is still encouraged.
Study on harmless and resource utilization of spent cathode carbon washing process
Authors: Zhi Pengkuo , Ou Yujing , Li Chunlei , Wang Yiru , Zhao Dan
Published: April 2020

Spent cathode carbon is the main hazardous waste in the electrolytic aluminum industry, which seriously pollutes the environment. In this paper, the spent cathode carbon is treated by the water washing process to change it from hazardous waste to solid waste, so that the environment is protected and NaF is also utilized. The optimum conditions were determined by experiment: t=50 min, T=80°C, L/S = 20:1. The raw materials and the washed products were characterized by elemental analysis, X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM).
Bioturbation enhances the removal of petroleum hydrocarbons in sediments by bacteria
Authors: Zhao Wenbo , Yan Bo , Zhang Xin , Liu Xianbin
Published: April 2020

A labortatory experiment was designed to study the removal of total petroleum hydrocarbons (TPH) by bacteria-bioturbation in the sediments. TPH were detected on 0, 5, 10, 14, 17, 20, 24 d in different phases and the removal rate in different layers of TPH in sediments was measured. The results showed that there were three results about the fate of TPH in the sediments: transfering to seawater by bioturbation; accumulating in the worms by feeding and degrading by bacteria. The removal rate of TPH in joint repairing group (JRG) was obviously higher than other three groups and reached to 86.01%, 83.58% and 75.56% in upper, middle and lower layers, respectively. The concentration of TPH increased 2.9264 mg/L in seawater and 12.7514 mg/kg in worms, imply that feeding by worms is an effective way to remove TPH in the sediments. The result of orthogonal experiment in the laboratory demonstrated that the best conditions to remove TPH by bacteria-bioturbation is: A. density of worms, 200 ind/m2; B.volume of bacterial fluid vaccination, 25 mL; C. salinity of seawater, 23; D. pH of seawater, 8.5; E. cultivation time, 12 d.
Policy analysis and technical evaluation index of multi-energy complementary projects in China
Authors: Li Yongtian , Zhang Huan , Xiu Kehua , Li Jiao , Li Hai
Published: April 2020

Multi-energy complementary renewable energy system is an efficient energy supply system based on thermoelectric-gas-storage coupling technology to realize full renewable energy supply in local regions, with biomass power generation as the basic energy, wind, light and storage as the supplement. Since 2000, China has promulgated a series of policies related to multi-energy complementarity to promote energy reform and renewable energy development. China supports the construction of multi-energy complementarity, micro-grid and renewable energy projects. By optimizing the process route of “source-network-load-storage” and adopting chain and vertical integrated feedback as auxiliary technical measures, the deficiencies of renewable energy projects in energy production, storage, transportation, conversion, use and recovery can be complete. Intelligent dispatch through “end-pipe-cloud” integrated energy management platform can compensate the characteristics of non-flexible operation, uncertainty and volatility of renewable energy. According to the characteristics of renewable energy in multi-energy complementary projects, technical evaluation index, economic evaluation index and social benefit index are established, and the advantages and disadvantages of renewable energy projects are evaluated by multi-dimensional indicators.
An experimental investigation on the transient heat transfer characteristics using air/water droplets two-phase flow
Authors: Abed A H , Shcheklein S E , Pakhaluev V M
Published: April 2020

The present study focused on evaluating the heat transfer behavior and predicting the surface resulting status during air/water droplets two-phase flow. Transient heat transfer based on the lumped capacitance model (LCM) was investigated experimentally under a range of water droplets concentration, surface temperature, and varying Re number. Compared with a single-phase air cooling, the transient surface temperature decreased with the increase in water droplets concentration and Re number. At the same cooling time, the surface temperature decreases about 13.5%, 47%, and 53.2% for (j = 46.79 – 111.68 kg/m2 hr). It was also noticed that the heat transfer coefficient increased with the increase in water droplets concentration and reach its maximum value at (j = 111.68 kg/m2 hr). Based on the analysis of the experimental results, the heat transfer mechanism due to the impacting of water droplets on the sphere surface was classified into three important physical regimes. Clear convection heat transfer regime corresponds to the dry region (region I); Convection and evaporation regimes correspond to the dry-out and wet regions (region II and III).
Numerical and Experimental Investigation of heat transfer and flow structures around three heated spheres in tandem arrangement
Authors: Abed A H , Shcheklein S E , Pakhaluev V M
Published: April 2020

The objective of this work is to evaluate the convective heat transfer and flow characteristics around three heated spheres in a tandem arrangement. Numerical simulation and Experimental verification were performed using stationary copper spheres located inside a cylindrical channel with constant channel-to-sphere diameter ratio. Numerical simulation is done for three-dimensional steady-state flow using ANSYS-FLUENT by solving the Reynolds-Averaged Navier Stokes (RANS) equations. Over the test range of Reynolds numbers (2500-55000), the numerical results of the average surface temperature and heat transfer coefficient obtained are a reasonably good agreement with those obtained by experimental measurements. The distributions of the heat transfer coefficient, temperature profiles, velocity field and pressure coefficient around the sphere’s surface are calculated and analyzed.
Experimental investigation on the enhancement of heat transfer by using carbon nanotubes CNT taunit m series
Authors: Ali A J , Jaber H J , Habeeb L J , Tugolukov E N
Published: April 2020

The enhancement of heat transfer is considered as one of the important tasks for controlling the energy dissipation and consumption. In order to secure this task, it is intended to increase the efficiency of heat exchanging systems taking into account the economic and environmental considerations. This work aims to test experimentally the effect of nanoparticle concentration functionalized carbon nanotubes (FCNT Taunit M) in water and Reynolds number on the heat transfer coefficient. Three concentrations of 0.01, 0.05, 0.1 vol.% for FCNT taunit have been used. The heat transfer augmentation of the nanofluid was investigated experimentally through a test rig constructed for this purpose under constant heat flux range (16061-22682) W/m2 at the developing region with Reynold number range 5000, 7000 and 9000 have been used. The particle size 12 nm for FCNT Taunit M. The experimental results revealed an augmentation in the Nusselt number as the volume concentration increased. The economic aspect was taken into account in this study. Pressure drop can be neglected because the increases were very small.
Possibility of using associated petroleum gas as a fuel for a production boiler house
Authors: Balzamov D S , Balzamova E Yu , Bronskaya V V , Valitov N V
Published: April 2020

Current legislation of the Russian Federation sets requirements for oil companies for utilization of produced associated petroleum gas (APG) at the level of 95%. Thus limiting its burning in torches in the fields. The most convenient way of APG utilization for oil companies is to pump it back into the reservoir, which sometimes allows to increase oil recovery. APG is also used for commercial generation of electricity and heat in fields by burning in gas turbine and gas-piston installations. Given the cheapness of associated gas in comparison with natural gas (NG), it is promising to replace NG with APG for large production boilers located in the immediate vicinity of the associated petroleum gas pipeline. The article provides a comparative analysis of the parameters of APG and NG, a scheme for preliminary preparation of APG for its subsequent combustion in the boiler room, an analysis of the performance of the boiler house to generate thermal energy, the feasibility of using APG as the main fuel for the production boiler room.