bluuebunny/crossref_metadata_2025 huggingface dataset:
Landscape characteristics of Codot Coffee in Kota Agung Utara Forest Management Unit, Lampung
Authors: Riyanto D , Wulandari C , Darmawan A
Published: April 2020

Codot coffee is a new coffee variety produced fromcodotor fruit-eating bats activity. This coffee is produced from bats spitting activity after they eat a full ripe coffee bean. We believed that there are interactions between coffee and codot along the landscape that can be withdrawn by using Geographic Information Systems (GIS). The purpose of this study is to determine the landscape characteristics of the distribution of codot coffee over Community Forest (Hutan Kemasyarakatan/HKm) area in Kota Agung Utara Forest Management Unit (FMU) (Kesatuan Pemangkuan Hutan/KPH). The codot coffee’s points were collected using direct GPS survey technique followed by spatial analysis. It was indicated that codot coffee has a tendency to exist between 0 to 300 m from the river, and more than 1,000 m from the road. The buffer analysis results of codot coffee distribution showed that codot has a tendency to require forests as a place to live and rest. Data showed that codot coffee mostly found in the slope between 15 to 30 percent and in the slope of 0 to 7 percent. The codot coffee were only found in area within 500 to 900 asl.
Tree and plant interactions in the agroforestry system: does the management of coffee intensification disrupt the soil hydrological system and pine growth?
Authors: Suprayogo D , Azmi E N , Ariesta D A , Sutejo Y A , Hakim A L , Prayogo C , McNamara N P
Published: April 2020

With increasing population pressure on forests in Perhutani land, coffee industrial plants are integrated in Pinus merkusii forests as agroforestry systems in the Community-Based Forest Management program especially in Java. This condition raises the research question (1) whether the growth of pine plants is not affected by the integration of coffee plants with various management?, (2) whether with more intensive management of coffee will be able to improve the growth and production of coffee plants? (3) Does the increasing coffee management will decrease the availability of soil water for coffee plant and pine trees?. This research was conducted with a nested design with one research factor, namely coffee management actions. There are 5 types of coffee management treatment namely (1) no management, (2) coffee with pruning, (3) coffee with laid-down the stems, (4) coffee with pruning and combined with fertilization and (5) reducing a half the pine population, with pruned coffee. The conclusion of this study is that pine growth, which is generally planted as a production forest in Perhutani, will experience a very significant decline if it is converted into a coffee-pine-based agroforestry system. However, as a social function of the forest area, the agroforestry system is still recommended if farmers do coffee treatment with regular pruning and fertilization. Perhutani’s recommendation by reducing a half the pine population in the age of 10 years is appropriate to facilitate the interaction of coffee and pine so that water and nutrient competition can be reduced.
Agroforestry systems and practices in hilly uplands of Misamis Oriental, Philippines
Authors: Palma R A , Canencia O P , Tiongco L E , Boniao R D , Florida E J , Dagonio J Y
Published: April 2020

A total 140 agroforestry farmers were randomly identified. The data were collected using survey questionnaires, formal interviews and reconnaissance surveys. Generally, the farmers were mature (51 yr and over), male, married, and had not finished a college degree. In spite of this, adoption of Falcata-based agroforestry practices was high as exemplified by the number of adopters, presence of various tree, agricultural crops, and animals. The study also revealed that tenurial status and farm size were the main factors hindering agroforestry adoption. Land owners with a large area are most likely to adopt different agroforestry practices. Tenants preferred to plant cash crops due to the issues on the right to choose what to plant, privacy of land and security of products and uncertainty on the length of time to cultivate the land. Most respondents practiced multistorey, intercropping, alley/hedgerow intercropping to maximize land utilization, and thereby produced a diversity of crops.
Configuration of resource access explaining the performance of community forest farmer groups in Gunungkidul, Yogyakarta
Authors: Hardianti A L , Permadi D B , Rohman
Published: April 2020

After more than 10 years managing state forestland under a social forestry program, community forestry’s farmer groups in Gunungkidul have shown differences in terms of their performance quality. The resource accesses (defined as the ability to benefit from certain resources) as stated by the theory of access (Ribot and Peluso, 2003) could affect their performance and subsequently their overall benefits from the social forestry program. This study aims to understand which configurations of resource access affecting the performance quality of forest farmer groups. In-depth interview and observation were carried out on the six forest farmer groups, covering the different degrees of success. The data were collected to measure the level of conditional variables (resource access) and outcome variable (the performance). The level of performances are indicated by forest conditions, institutional and business aspects. This paper applied Qualitative Comparative Analysis (QCA) with a four-value fuzzy set methodology to conduct a systematic cross-case comparison using fsQCA software to analyze the relationship between the condition and outcome variables. The results showed that two configurations of resource access profoundly explained the successful performance of the farmer groups. The first combination consists of access to knowledge, technology, financial, market, and social capital which can be found in Sedyo Rukun and Sido Maju II. Each of the access in the first combination contributes 30% towards the performance. The second combination consists of access to knowledge, technology, financial, labor, and social capital which explained the condition of Sedyo Lestari, Sedyo Makmur, dan Sido Dadi. Each of the access contributes 56% towards the performance. The prime implicant for successful quality performance is found in access to knowledge, indicating that farmer-to-farmer learning and extension services from third parties are required to be encouraged in social forestry programs.
How NGO fulfill the complex scheme of social forestry: a resume of SF scheme in Indonesia
Authors: Rahayu S , Laraswati D , Pratama A A , Permadi D B , Sahide M A K , Maryudi A
Published: April 2020

The Indonesian government shows a great commitment in allocating forests for community management through social forestry policies covering an area of 13,847,722 ha. The role of NGOs in realizing the implementation of social forestry in Indonesia cannot be ignored. They impetus the community to get legal permits in forest management, assist in preparing business plans, area management plans, and institutional management. This article explores the role of NGOs in the implementation of social forestry during the Jokowi-JK administration. We support the argument that NGOs play an important role in the implementation of social forestry, as evidenced by the achievement of permits and policies of the Ministry of Environment and Forestry recognizes that NGOs are formally involved in social forestry implementation.
Learning centres potentials for supporting NTFPS production from agroforest systems
Authors: Syarifah F A , Martini E , Trikoslamet  , Al-Hasan R
Published: April 2020

Extraction practices of NTFPs without introducing its domestication techniques have the potential to cause the extinction of the particular product or species. Currently, techniques to domesticate NTFPs under agroforestry systems have been explored, with two examples of economically valuable NTFP commodities are Trigona bee (Trigona sp.) and Bambu Tabah (Gigantochloa nigrociliata). Although techniques for its domestication have been identified, not much farmers know and understand how to domesticate the commodities. Government extension services are not yet disseminating information on NTFPs domestication, alternatives extension services approaches need to be explored to widespread information on NTFPs domestication to farmers. Learning centres can be one of the approaches that can support the dissemination of NTFPs domesticaion. This study was conducted to explore potentials of learning centres to support NTFPs production from agroforestry systems. Two case studies were taken, i.e. Trigona in Gunungkidul District and Bambu tabah in Lombok Tengah District. Information was collected to explore the potential adoption level of domestication techniques introduced by the learning centre, through interview with 60 learning centre visitors in Lombok Tengah and 55 in Gunungkidul. The study showed that learning centres increased the adoption potential of the NTFP domestication, particularly through facilities that were given to the community to be tested in their own plot. However, farmer’s accessibility to visit the learning centres are still limited. Government supports is needed to enhance farmers’ accessibility and development of learning centres as part of their forestry extension services programs for enhancing production of NTFPs as sources for local livelihoods.
Private forest in facing the timber legality regime in Indonesia: the NGOs’ role
Authors: Laraswati D , Rahayu S , Pratama A A , Soraya E , Sahide M A K , Maryudi A
Published: April 2020

Private forest becomes a role model of sustainable forest management in Indonesia. Not only it is able to rehabilitate critical lands, but it also significantly contributes to meet the community daily needs and wood-based industries due to using agroforestry system as its management practice. However, in 2009 the Ministry of Environment and Forestry (MoEF) of Indonesia decided to implement a timber legality assurance system as a mandatory instrument including for private forest. However, the administrations and procedures are complicated. Private forest thus faces new challenges to obey the complication of the system. NGOs are often mentioned as the most contributing actor in solving private forest difficulties. This paper thus attempts to shed light on the challenges faced by private forest because of the timber legality policy and how NGOs take their role.
Preparation and characterization of fatty acid eutectic/diatomite filter aid form-stable phase change material for thermal energy storage
Authors: Meng Duo , Wang Anqi
Published: April 2020

The aim of this study is to prepare a form-stable phase change material (PCM) with capric and lauric fatty acid (CA-LA) eutectic as the heat absorption material and diatomite filter aid as the supporting matrix. The method of vacuum impregnation was conducted to prepare the composite PCM which has high thermal performance. Its characteristics such as microstructure, thermo-physical propertiesand thermal stability were investigated by SEM, FT-IR, DSC and TG technique. The adsorption capacity of diatomite filter aid to CA-LA eutectic was 49wt%, and the composite PCM kept solid in macro-level even when the CA-LA melted due to the capillary and surface tension forces of diatomite filter aid. DSC analysis showed that phase change temperature and latent heat of the form-stable PCM was 21.8°C and 75.45 J·g-1 respectively. TG analysis indicated that the diatomite filter aid particles absorbed and constrained the CA-LA molecules in the pores and confirmed the form-stable property of the composite. After 100 times thermal cycling, the phase change temperature and latent heat of the form-stable PCM respectively decreased by 0.9% and 1.1%, which can be neglectable in the practical engineering application.
Decentralized cooperative optimization method to enhance discharging efficiency of distributed energy storage system
Authors: Huang Kun , Fu Ming , Zhang Xiaoyan
Published: April 2020

A decentralized cooperative optimization method is proposed in this study to improve discharging efficiencies of distributed energy storage systems (DESSs) in a smart distribution network (SDN). The proposed method achieves global information or control coordination only through local information interaction between neighbour agents without centralized agents. It is accomplished by using the improved consensus-based information discovery and pinning algorithm of multi-agent system (MAS), which obviates the need for a central controller. Meanwhile, the proposed method coordinates DESSs and the corresponding discharging efficiencies using associated marginal costs in a decentralize way, that can maximum the discharging efficiency while reducing local power mismatch in a SDN. Representative simulation cases are carried on to verify the effectiveness and adaptability of the proposed approach.
Application of 3D embedded discrete fracture model for simulating CO2-EOR and geological storage in fractured reservoirs
Authors: Du Xulin , Cheng Linsong , Liu Yanqin , Rao Xiang , Ma Ming , Cao Renyi , Zhou Jinchong
Published: April 2020

For the purpose of greenhouse gas control and environment protection, CO2 emission reduction has become a hot spot in global research. CO2-EOR and geological storage are widely regarded as one of the most economical and promising emission reduction measures. In this paper, the 3D embedded discrete fracture model (EDFM) is built to simulate the interfracture CO2 flooding and geological storage process in fractured reservoirs. This model can deal with the complex geological conditions of three-dimensional arbitrary inclined fracture networks, significantly improve the calculation efficiency, and accurately evaluate the CO2-EOR process of real reservoirs. The obtained CO2 reserves and saturation distribution can provide key technical parameters for field operations.
Sedimentary characteristics and exploration direction in the south of the central block in Pre-Caspian Basin
Authors: Sheng Shanbo , Wang Zhen , Liang Shuang , Cai Zheng
Published: April 2020

The Pre-Caspian Basin experienced the history from the Late Paleozoic craton margin to the Mesozoic-Cenozoic depression. It has been explored for a long time. It is the most important oil and gas producing area in Kazakhstan, and a large number of oil and gas fields have been discovered in it. The oil and gas discoveries are located in clastic rock and platform carbonate rock below the Lower Permian salt domes. The study area is located at the eastern margin of the Pre-Caspian Basin, where reservoirs are deposited in an open carbonate platform in the shallow sea. The most developed subfacies are intraplatform shoals and sea between shoals. The microfacies in the intraplatform shoals include bioclastic shoals and algae shoals, and represent dominant high-quality reservoirs. The central gentle zone and the eastern slope zone in the study area are potential targets for exploration and evaluation. All reservoirs are structural-lithologic reservoirs controlled by high lithologic barriers or updipped pinch-outs.
Numerical simulation of pressure distribution in a walking-beam type reheating furnace
Authors: Li Chaoxiang , Huang Yajun , Sun Junbo , Ni Yang , Lu Linlin
Published: April 2020

Numerical simulation of pressure distribution in a walking-beam reheating furnace was accomplished using FLUENT software. The effect of partition walls in the preheating zone on the flow field and pressure distribution in the reheating furnace was studied. The numerical results show that the partition walls in the preheating zone have an important influence on pressure distribution and temperature distribution in the reheating furnace. In order to improve the pressure distribution and the temperature uniformity in the reheating furnace, the partition walls in the preheating zone were retrofitted. After the partition walls retrofitting, the pressure distribution and the temperature distribution in the reheating furnace were improved. The heating efficiency of the reheating furnace was improved. Therefore, numerical results have great significance for improving pressure distribution and temperature distribution in the reheating furnace.
Test study of the water quantity loss of cooling tower on U-type liquidometer
Authors: Song Baohong
Published: April 2020

The water loss of a wet cooling tower was analyzed by changing the collection method for the collecting basin level data. The water quantity loss of the cooling tower was measured using a U-tube liquidometer to obtain real-time and accurate data. When the liquid level of the collecting basin decreased by 1 mm, the water quantity loss of one cooling tower was 1.38 m3. In stable engineering application operation and under different environmental and climatic conditions, the water quantity loss was between 13.83 kg s−1 and 18.07 kg s−1. Through the accurate measurement of the collecting basin level and the established water quantity loss law of the cooling tower, the correctness of Merkel assumption of air saturation in the cooling tower is analyzed. In addition, the variation laws of the evaporation and drift losses of the cooling tower were established. The testing and theoretical analysis of water quantity loss by using a test device will be widely used in the design and other related engineering fields, such as the control and research of the water quantity loss of the cooling tower and the drift recovery.
Research on integrated operation and maintenance acquisition and monitoring technology for new generation dispatching control system
Authors: Yu Fang , Sun Mingyang , Zhuang Weijin , Wang Yan
Published: April 2020

Focusing on the intelligence demands of operation and maintenance for the new generation dispatching control system and the technical requirements of pre-monitoring, early warning and fault handling in the event, based on the architecture with the characteristics of physical distribution and logical integration, this paper designs a kind of integrated operation and maintenance acquisition and monitoring method. It first builds the full model of the automation equipment operation information, collects and summarizes the operation information such as resource pool, platform status, database, application and multi-activity consistency and data consistency, then achieves real-time data acquisition of various key indicators information for the operation of the new generation of control systems; Through the wide-area system service bus, the system operation information is gathered into the integrated operation and maintenance center to realize panoramic monitoring of the operation status for the multi-activity analysis decision center, the dual-active model data center and the dual-active monitoring system, and to comprehensively improve the intelligent level of operation and maintenance for the new generation dispatching control system.
Peak-valley time division model based on net load curve
Authors: Guo Junhong , Xue Xiaoqiang , Li Ling , Cheng Yiping , Li Yajie
Published: April 2020

As China has been quickly promoting its power market reform, the degree of thermal power units participating in market transaction has been gradually deepened. Aiming at different situations of load, thermal power units need to adopt bidding strategy accordingly. In power system with high proportion of renewable energy, the competition curve that thermal power units actually face is no longer total load curve. Proper division of peak-valley time intervals will guide thermal power units to adjust bidding strategy positively and effectively in the competition. A net-load-curve-based peak-valley time division model is built in this paper with the help of K-means algorithm. And then the paper contrasts and analyses the distributive characteristics of total and net load curves through a calculation example to verify the positive effect this model has on accurate bid for thermal power units.
Optimized dispatching based on wind-photovoltaic-hydropower-thermal-bundled strategy
Authors: Wang Xi , Liu Fang , Wang Yunling , Zhu Mi , Liu Ying , Lin Zhiyu , Li Huaqiang
Published: April 2020

The rapid development of wind power and photovoltaic is conducive to optimizing the energy structure and resolving fossil energy crisis, in response to the strategic direction of energy saving and emission reduction in China. However, the intermittence and fluctuation of wind, photovoltaic and other renewable energy sources pose greater challenges to the secure and stable operation of the power grid. Therefore, it is of theoretical significance and practical value to study the optimal dispatching of power system with wind and photovoltaic large-scale connected to grid. This work proposes an optimal scheduling strategy based on wind-photovoltaic-hydropower-thermal bundled according to the energy sources reasonable allocation proportion. The strategy gives full play to the complementary characteristics of energy, and realizes the comprehensive optimization of system peak shaving, economic cost and environmental benefit. The bundled power configuration layer defines the bundled fitness index, which takes into account the comprehensive influences of conventional unit utilization rate, load tracking degree and wind power abandonment. Based on the commercial optimization software CPLEX, the output of conventional hydropower units and the combination of thermal power units are solved. Finally, the feasibility of the model is verified by a case study.
Multi-SGI interconnected real-time HIL simulation of Yu’E MMC-HVDC project
Authors: Liu Chong , Zhu Yiying , Yang Limin , Yin Pingping
Published: April 2020

With the interconnection of regional grid and wide application of HVDC and FACTS in power grid, the scale of grid is increasing rapidly, and this makes the power system simulation techniques face new challenges. In this paper, based on decoupling algorithm and high speed optical fiber communication, the interconnection between multi-SGI(multiple SGI supercomputers) is proposed to implement HYPERSIM co-simulation. The HIL test of Yu’E MMC-HVDC project is implemented using the HYPERSIM co-simulation platform, the test results verify the real-time simulation capability of the proposed scheme.
Experimental and numerical investigation of combustion system improvement on 600MW bituminous coal boiler for burning lignite coal
Authors: Xu Yanhui , Guo Xin , Yu Qiang , Huang Ying , Wang Jingjie , Sun Hao , Ma Xiaochun , Guan Jingyu , Li Wei , Song Zhenyu , Jia Geng
Published: April 2020

A 600MW supercritical direct-current (DC) utility boiler co-firing bituminous coal with lignite, has the problems from over-large desuperheating water yield in the reheater and over-high NO
x
emission concentration. In this paper, the causes of the problems are analyzed through, the initial tests of pulverization system and combustion system, the adjustment of combustion, etc. The results show that the combustion in furnace lagged behind to some extent after co-firing the bituminous coal with the lignite and the center of the flame was elevated, which shortened the relative distance between the flame of the main burners and over fire air(OFA), enlarged the absorbed heat amount of the reheater and reduced the residence time of flame in the reduction zone prominently. The much less residence time would increase NO
x
emission. Based on the calculations of the actual operation conditions of the burners, a series of improvement measures were proposed. After performing numerical simulation and cold test verification for the improvement measures, the corresponding transformations of the power plant were carried out. The desuperheating water yield in the reheater decrease, obviously, and over-high NO
x
emission is controlled effectively.
Hydraulic turbocharger for energy recycling in the reverse osmosis seawater desalination system
Authors: Ji Yunguang , Li Xiaoxia , Li Hongtao
Published: April 2020

In order to reduce the energy consumption of the reverse osmosis seawater desalination process, a hydraulic turbocharger is proposed to recycle the pressure energy of the brine. A high efficiency energy recovery hydraulic turbocharger is designed based on Computational Fluid Dynamic method and installed in the reverse osmosis seawater desalination system of Dagang Power Plant in Tianjin Development Zone, China. The actual operation results show that the hydraulic turbocharger has apressure energy recovery efficiency of up to 72%, and with high working stability and low noise, which may provide areliable reference for the design and application of pressure energy recovery devices.
Precipitation forecast on the township scale using the frequency matching method
Authors: Wang Shusu , Yu Li , Zhu Shoupeng
Published: April 2020

Based on the daily accumulated precipitation from the European Centre for Medium-Range Weather Forecasts (ECMWF) as the forecast data, and the daily accumulated precipitation from ground meteorological stations as observations, experiments of precipitation forecast on the township scale are carried out by means of the frequency matching method. The results show that, compared with the bilinear interpolation, the frequency matching method is more effective in increasing the anomaly correlation coefficient and the equitable threat score, as well as decreasing the root-mean-square error, the false alarm rate of light rain and the missing rate of heavy rain. The frequency matching method can greatly calibrate and improve the refined precipitation forecast on the township scale.
Prediction and research on the erosion of the tubing joint in high yield gas well
Authors: Ni Hongjian , Cao Yucheng , Liu Chengwen
Published: April 2020

Sand production in high-yield gas-well is a common problem in oilfield. Erosion caused by sand production, often leads to pipeline failures and even endangers lives and property if serious. So, the sand production problem cannot be ignored. In this paper, computational fluid dynamics are used. I conduct numerical simulation in allusion to the process of gas flowing through pipeline with sand, with FLUENT software, and then discuss the influence on erosion caused by the flow velocity of gas, the flow rate of sand, the diameter of particles and so on. The following conclusions are drawn: with the increase of natural gas flow rate, the average erosion rate at the tubing joint increases gradually and is approximately exponential to the natural gas flow rate; with the increase of sand flow rate, the average erosion rate at the tubing joint increases gradually and is approximately linear to the sand flow rate; with the increase of sand particle size, the erosion rate at the tubing joint decreases gradually.
Prediction of gas emission based on grey-generalized regression neural network
Authors: Chen Yanqiu , Zheng Linjiang , Huang Jing , Zou Zhe , Li Chunhui
Published: April 2020

Coal mine gas is one of the main factors endangering mine safety in China, and the amount of gas emission is affected by a variety of related factors, which have the characteristics of non-linearity and uncertainty. In order to predict gas emission more quickly and accurately, a coupling algorithm of grey theory (GM (1,1) and generalized regression neural network (GRNN) is proposed. Thirteen parameters, such as coal seam gas content, depth and GM (1,1) gas emission prediction value, are used as input of the model. The input parameters are normalized and used as training and testing samples of the model. The 10 fold cross validation and minimum root mean square error (RMSE) are used to find the optimal smoothing factor (spread), then a non-linear prediction model of gas emission is established. The gas monitoring data of Qianjiaying Mining Area of Kailuan Mining Group from May 2007 to December 2008 are used in the experiment. The results show that the model has a great improvement in convergence speed and a good accuracy, which can provide theoretical basis for the prevention and control of coal mine gas disasters.
Study on the preparation of composite MnO2
Authors: Qing Hui , Xu Su , Kuang Huizi , Liao Wen Chao , Huang Xiaodong , Zhang Xiuxiu
Published: April 2020

The manganese dioxide (MnO2) is a material that has broad application prospects and economic value, which is used in various fields. However, the poor conductivity, less active sites and the easy collapse of the structure during the reaction, limit application. In this paper, three kinds of MnO2 were prepared by simple method, α-MnO2, β-MnO2, and γ-MnO2. And the properties of the sample were further analyzed by Brunauer-Emmett-Teller (BET), X-ray diffffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX) and fourier transform infrared spectroscopy (FTIR). Then α-MnO2 was chosen as the precursor of this study. Three different ratios of transition metal Ni and Co are respectively loaded with α-MnO2. Electrodes made of 7 different samples including α-MnO2, complete cyclic voltammetry test. Results show that: (1) α-MnO2 is not easy to collapse and suitable for precursor; (2)the addition of metal Ni and Co increases the specific surface area of the material to varying degrees. Co@a-MnO2-2 has the highest specific surface area and porosity, which can provide more active sites when applied; (3)all seven samples have good capacitance characteristics. The best is Co@a-MnO2-0.5, but Co@a-MnO2-2 is very close to Co@a-MnO2-0.5. Comprehensive analysis, the best ratio for this study is Co@a-MnO2-2.
Study of wave load computation based on diffraction theory
Authors: Chen Zhi , Du Yu , Liu Yanjun , Liu Hengyu , Xue Gang
Published: April 2020

With the development of the ocean resources, the design of the offshore platform attracts increasing attention. The wave load computation is an important part for the design of the offshore platform. Currently, model experiments are mainly used to get the wave load of the offshore platform, which is complex, inefficient, and error-prone. To improve the efficiency of calculation, more simplified formulas for the wave load computation were deduced based on the wave diffraction theory. Moreover, a simple method was proposed based on the Matlab and software was developed to calculate the wave load. Experiments were conducted by a designed cylinder floater model to obtain the values of the wave load. Some simulations were made to calculate the wave load under the condition that water depth, wave frequency and other relevant parameters were same with the experiments. The wave load values calculated by the software had similar change trends with that of the experiment data, which proved the feasibility of the formulas for the wave load computation based on diffraction theory and the accuracy of the numerical algorithm in the computation of wave load based on Matlab. Compared with the model experiments, the software based on the diffraction theory was a cheaper and convenient way to obtain the values of wave load when the platform in the ocean is designed. So the new method will improve the efficiency in the wave load computation and is in favour of the design of offshore platform.
Robust day-ahead dispatch for combined heat and power microgrid considering wind-solar power uncertainty
Authors: Wang Xi , Deng Yingying , Ren Zhichao , Wang Haiyan , Chen Shi , Jia Chuyun , Ye Yanli
Published: April 2020

Due to the energy crisis and environment pollution, small-scale wind power and photovoltaics have been widely deployed in power system using microgrid (MG). Moreover, several researches have focused on incorporating various energy forms into MG. However, the uncertainties of wind power and photovoltaics may significantly impact the security and economy of the MG operation. To deal with this issue, this paper presents a two-stage robust model to achieve the optimal day-ahead economic dispatch strategy involving uncertain wind power and photovoltaics. The first stage decides the initial day-ahead dispatch strategy before the realization of uncertain wind power and photovoltaics. The additional adjustment action is made in the second stage as long as the uncertainties are observed. The column and constraint generation (C&CG) decomposition is employed to decompose the original model into the day-ahead dispatch master problem and the additional adjustment sub-problem. Based on the duality theory and Big-M approach, the sub-problem with complex max-min structure can be converted into a tractable mixed-integer linear programming (MILP) problem. Therefore, C&CG iteration algorithm can be further implemented to achieve the optimal day-ahead economic dispatch strategy for the MG. The experimental results of the comparisons to the deterministic optimization demonstrate the effectiveness of the presented optimization.
Development of fast simulation models of photovoltaic generation system based on MATLAB
Authors: Luo Shanshan , Chen Bing , Shi Mingming
Published: April 2020

Based on the mathematical model of photovoltaic power generation system, the simulation model based on MATLAB/Simulink is given. Traditional simulation models have the drawbacks of rapidity and poor robustness. In this paper, two equivalent simplified models based on inverters are established—the equivalent switch model and the average model. In this paper, the above three models are compared comprehensively from different aspects such as simulation speed, simulation precision and robustness, and the applicable occasions of each method are proposed.
Two-stage stochastic scheduling model of wind-photovoltaic-storage providing flexible ramp capacity
Authors: Huang Ruanming , He Xinqin , Zhao Jingjing , Fei Fei , Guo Mingxing
Published: April 2020

The increasing penetration of renewable energy resources in power system has contributed to the increasing demand for operation flexibility. To address the deficiency of flexibility in wind-photovoltaic-storage hybrid system with deepening penetration of intermittent and uncertain renewable energy resources, this paper proposes emerging flexible resources including wind, photovoltaic and energy storage providing flexible ramp capacity to improve flexibility. Considering the uncertainty of load and intermittent generation, the wind-photovoltaic-storage providing flexible ramp capacity are integrated into a two-stage stochastic dispatch model including 1h day-ahead unit commitment and 15min real-time economic dispatch. To test the efficiency of the proposed model, simulation are carried out on a modified IEEE 118-bus with 54 thermal units, the results indicate that wind-photovoltaic-storage providing flexible ramp capacity can effectively alleviate the deficiency of operation flexibility, and improve the overall economic benefit.
A new approach to reduce AC grid for coupled HVDC systems
Authors: Dou Fei , Wang Weiyuan , Xu Yiqing , Wang Lijun , Yu Xuan , Xue Jiliang
Published: April 2020

When the dynamic performance study of the HVDC system are carried out or the over voltage characteristics is analysed, electromagnetic transient simulation is needed. The reduction of the AC system is inevitable since the computation burden is huge taking the whole ac grid as well as detailed HVDC models into account. Because the task is to maintain the dynamic response of AC system in a short term and focuses inside the HVDC transmission system, reasonable reduction of the ac grid can be done to simplify this problem without effecting the analysis conclusion. However, the existing approaches to reduce large ac grid aims to analyse the transient stability under asymmetric faults. In these methods, the remaining ac grid is still too large considering full HVDC models which is usually represented by simplified ones. In order to solve the specific aforementioned problem, multi-port Thevenin equivalent is adopted to simplify the original large power grid. By the transient stability simulation and short-circuit calculation, the node impedance matrix can be obtained. According to the admittance matrix obtained by the impedance matrix, the structure of the equivalent system as well as the impedance of the source are determined. The power flow of the equivalent system approximates that of the original system based on the quadratic programming. A UHVDC hierarchically connecting to girds of two voltage levels i.e. 500 kV and 1000 kV is taken as an example, which verifies the validity of the proposed method. Given the relatively small scale of the reduced system, further study on the full HVDC system can be done under computational constraints.
Simulation analysis of boiler high temperature corrosion atmosphere under lean oxygen operation
Authors: Xu Hong , Xu Weigang , Tan Houzhang
Published: April 2020

High-temperature corrosion is a major threat to the safe operation of thermal power plants. The reducing atmosphere induced by boiler lean oxygen combustion has close relation with the water walls corrosion. In this paper, the reducing atmosphere such as CO, H2S concentration distribution was simulated targeted on a boiler. Under the full load, the atmosphere and the temperature distribution in low nitrogen combustion mode were further studied on different excess air ratios and the rates and position of the SOFA air conditions. With the SOFA rate increasing, the flame centre moved up, the boiler temperature is more uniform, and the temperature at the furnace outlet increased. the concentration of CO and H2S in the main combustion zone is obviously increased. In the burnout zone, there is almost no CO and H2S due to the supplement of SOFA.
Risk-based configuration of current limiters in large scale power systems
Authors: Li Zong , Kuai Shengyu , Xia Kai , Yang Mengmeng , Feng Peiru , Shen Yuming , Wang Jiaqing , Tian Jia
Published: April 2020

The short-circuit current level has become the most prominent constraint for composite power grid. Consequently, it is of unprecedented necessity to adopt specific measures to limit the short-circuit current levels in transmission network planning. A multi-objective model is proposed in this paper to configure current limiting measures. The proposed model is risk-based which considers both the occurrence probabilities and consequence severity levels of short circuit events. NSGA-II is utilized to solve the Pareto proposed model, which provides a Pareto set of optimal current limiting solutions, rather than a single solution. This proposed method effectively enhances both the cost-effectiveness and decision flexibility in current limiting planning.
Vibration fault diagnosis and dynamic balance processing analysis of blower in thermal power plant
Authors: Li Peng , Pang Le , Lin Zhongpeng
Published: April 2020

The fan vibration of the forced draft fan in a power plant is too large during normal operation, which seriously affects the normal operation of the unit. Through the vibration detection, on the basis of comprehensive analysis of the fan vibration failure mechanism, the means of adjusting the balance of the fan is adopted to reduce the excessive vibration to an excellent level. This paper introduces an excessive vibration fault caused by a device imbalance problem that is treated by vibration detection and dynamic balance test. The article elaborates the diagnosis method, diagnosis process and treatment suggestions, and deeply analyses and summarizes the characteristics of rotor imbalance, and provides reference for the diagnosis and analysis of the same type of fault.
Evaluation of the peak-shaving capability of the receiving-end power system with multi-infeed UHV
Authors: Wu Huahua , Yin Xunhu , Zhu Bingquan , Shen Shaofei , Zhou Xiaoming , Guo Libang , Ding Yi
Published: April 2020

Peak-shaving capability mainly refers to the capability of the power system to maintain the balance between the active output and load balance in real-time. Sufficient peak-shaving capability is one of the important conditions to ensure the security and stability of the power system. The access of multi-infeed ultra-high voltage will largely weaken the peak-shaving capability of the power system and thus increase its peak-shaving pressure. This paper first introduces the characteristics of renewable energy generation such as wind generation and photovoltaic generation since a large amount of renewable energy from the sending-end system through several UHV delivery often increases the peak-shaving pressure of the receiving-end power system. On this basis, it analyses the impact of multi-infeed UHV on peak-shaving of power system. Then, an evaluation method that uses equivalent peaking capacity to measure the peak-shaving capability of the UHV receiving-end power system with multi-infeed UHV is proposed. Finally, Zhejiang Power System is used as an example to evaluate its peak-shaving regulation capability in the typical years and the typical day using the proposed method.
Study on operation status of SCR denitration system in Chinese coal-fired power plants
Authors: Zhang Yang , Feng Qianwei , Li Sha , Xu Ketao , Pei Yukun , Zhu Yue
Published: April 2020

Since the beginning of the 12th Five-Year Plan, coal-fired power plants have carried out large-scale denitration and ultra-low emission transformation in China, among which SCR denitration technology is the most widely used. However, some hidden problems in the process of project implementation have gradually emerged after operation due to various factors, such as the centralized reconstruction task, lack of technical experience, inadequate quality control of main equipment, uneven quality of denitration catalysts, and insufficient operation and maintenance experience of power generation enterprises. In this context, the future direction of SCR denitration operation and maintenance management is proposed after a systematic summarization and analysis of the operation status of SCR denitration system in recent years to provide reference for subsequent work.
A review about radioactivity in TENORMs of produced water waste from petroleum industry and its environmental and health effects
Authors: Ali Mohsen M.M. , Zhao Hongtao , Li Zhongyu , Ayoub Anour A.T.
Published: April 2020

Produced water that detached from petroleum production process is often reimbursed into the surrounding environment. This might have negative impact for environment; it is usually infiltrate agricultural soil and contaminate groundwater with toxic elements. These waters are often contaminated by technologically enhanced naturally occurring radioactive materials (TENORMs). It may create specific environmental issues and health radiological threats to the inhabitants, especially inside the petroleum facilities or the local population that live in areas and use the groundwater for the usual living purposes. The aim of this work is to provide an intensive review for the previous studies on the (TENORMs) that associating with the produced water from petroleum industry, and its environmental and health impacts in many areas around the globe. It is true that there is long term hazard associated with widespread behaviour of releasing produced water into the environments for both workers and local inhabitants as well as the environment itself. However, there is many studies suggesting that currently the situation could be considered in low hazard level in most of petroleum fields, but with increases in the extraction and use of petroleum, the discharge of produced water into the environment increases accordingly, this might be end up with negative impacts on the environment and health such as radiological contamination of aquatic and agricultural life.
The potential rate and microbial communities of dissimilatory nitrate reduction to ammonium in Pearl River Estuary
Authors: Jiang Ran , Yang Fang , Gou Wei , He Rui , Zhang Xinfeng
Published: April 2020

Since nitrogen-related eutrophication has become a severe problem in the Pearl River Delta area in China, it is crucial to have a deep understanding of the nitrogen cycle. This study investigated the existence of dissimilatory nitrate reduction to ammonium (DNRA) in sediments of the Pearl River Estuary using the 15N isotope paring method with continuous-flow systems. The results showed that the maximum

15

NH

4
+

was 389.7 nmol/g in 216 h, while the maximum DNRA rate of 4.68 nmol/(g wet sediment h) occurred in 120 hours. The principal components analysis (PCA) based on community composition at the genus level was performed by the nrfA sequences distributed in the nine sites covering a salinity range of 25.3 - 30.1%º, and forming four distinct clusters. There was no significant relationship between the potential DNRA rates in the spatial distribution and salinity, but the highest potential DNRA rate occurred near the sewage discharge in the western coastal area. High contents of nrfA gene fragments were found at the same site, with values of 1159715 copies/g wet sediment, while very low contents of nrfA were found at other sites. Based on the nrfA gene pyrosequencing, Enterobacteriaceae accounts for 89.9 - 99.0% of the classified sequences.
Water quality assessment in China Ningxia Section of the Yellow River using water quality identification index method
Authors: Hou Kai , Zhang Yuting , Qian Hui
Published: April 2020

The water quality of the Yellow River is related to the healthy development of industry and agriculture in Ningxia. According to the Ningxia Water Resources Bulletin 2012-2017, we selected three representative water quality indicators of ammonia nitrogen (NH3-N), total phosphorus (TP) and permanganate index (CODMn, and applied the single-factor and comprehensive water quality identification index method to evaluate the water quality of six national control sections in the Ningxia section of the Yellow River. The results showed that each section was most affected by NH3-N, followed by TP, and least affected by CODMn; The single-factor identification indexes of six sections were mostly falls into the category II, and the comprehensive identification indexes showed that the water quality mainly fell into the category II; Affected by the rapid development of the industry in this region, the water quality of the Mahuanggou section was seriously polluted.
Environmental monitoring system based on IOT android platform
Authors: Chen Jian , Wu Suwen , Xue Xiaoping , Zhang Shaqing
Published: April 2020

In order to realize remote monitoring of the environment, this paper uses the Android mobile platform to design an APP based on the Internet of Things environment monitoring system, which can display the environmental data (temperature, humidity and light intensity) of three different places. The system is a complete IoT application system consisting of ZigBee sensor network, gateway protocol converter, cloud server and mobile intelligent terminal. Users can use the mobile phone to display the current environment data by viewing the app.