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Reliability analysis of urban gas transmission and distribution system based on FMEA and correlation

Su LI,Weiguo ZHOU

《能源前沿（英文）》 2014年 第8卷 第4期   页码 443-448 doi: 10.1007/s11708-014-0336-4

摘要： In order to improve the safety management of urban gas transmission and distribution system, failure mode and effects analysis (FMEA) was used to construct the reliability analysis system of the pipeline network. To solve the problem of subjectivity and uncertainty of the multi-expert decision making, the correlation operator was introduced into the calculation of the risk priority number (RPN). Using FMEA along with weight analysis and expert investigation approach, the FMEA evaluation table was given, including five failure modes, risk priority numbers, failure causes and effects, as well as corrective actions. The results show that correlation operator can directly process the linguistic terms and quantify the priority of the risks.

关键词： gas transmission and distribution system     risk evaluation     reliability analysis     failure mode and effects analysis (FMEA)     correlation operator    

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Risk analysis methods of the water resources system under uncertainty

Zeying GUI,Chenglong ZHANG,Mo Li,Ping GUO

《农业科学与工程前沿（英文）》 2015年 第2卷 第3期   页码 205-215 doi: 10.15302/J-FASE-2015073

摘要： The main characteristic of the water resources system (WRS) is its great complexity and uncertainty, which makes it highly desirable to carry out a risk analysis of the WRS. The natural environmental, social economic conditions as well as limitations of human cognitive ability are possible sources of the uncertainties that need to be taken into account in the risk analysis process. In this paper the inherent stochastic uncertainty and cognitive subjective uncertainty of the WRS are discussed first, from both objective and subjective perspectives. Then the quantitative characterization methods of risk analysis are introduced, including three criteria (reliability, resiliency and vulnerability) and five basic optimization models (the expected risk value model, conditional value at risk model, chance-constrained risk model, minimizing probability of risk events model, and the multi-objective optimization model). Finally, this paper focuses on the various methods of risk analysis under uncertainty, which are summarized as random, fuzzy and mixed methods. A more comprehensive risk analysis methodology for the WRS is proposed based on the comparison of the advantages, disadvantages and applicable conditions of these three methods. This paper provides a decision support of risk analysis for researchers, policy makers and stakeholders of the WRS.

关键词： water resources system     evaluation criterion     optimization model     risk analysis method     uncertainty    

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Last Planner System and Scrum: Comparative analysis and suggestions for adjustments

Roshan POUDEL, Borja GARCIA de SOTO, Eder MARTINEZ

《工程管理前沿（英文）》 2020年 第7卷 第3期   页码 359-372 doi: 10.1007/s42524-020-0117-1

摘要： This study provides a critical review of the concepts of Agile, Lean, Scrum, and Last Planner System (LPS). A comparative analysis is conducted between LPS and Scrum to expand LPS by considering Scrum’s best practices. Eight dimensions, namely, 1) origins, 2) main purpose, 3) overall system/framework process, 4) tools or artifacts maintained by the team, 5) team composition and main roles, 6) regular events or team meetings, 7) metrics/dashboards, and 8) approach to learning, are evaluated. After analyzing side by side the eight dimensions, it was found that many aspects from Scrum already exist in LPS in the same or similar form. However, the authors identify four main elements from Scrum that can be leveraged to improve the LPS benchmark, such as considering the Scrum “Increment” concept into LPS, having a clear definition of roles and responsibilities, or adding an equivalent to a Scrum Master to have a designated “rule keeper” in LPS. These opportunities to be considered in new LPS benchmarks need to be tested and validated with real applications. To the best of the authors’ knowledge, this work is the first to comprehensively compare Scrum (Agile) and LPS (Lean) and could be seen as a contribution toward the evolution of the Last Planner System for the academic and industrial environments.

关键词： Lean Construction     Last Planner System     Agile     Scrum     comparative analysis     AEC projects     project teams    

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Energy and economic analysis of a point-focus concentrating photovoltaic system when its installation

C. RENNO, A. PERONE

《能源前沿（英文）》 2021年 第15卷 第2期   页码 384-395 doi: 10.1007/s11708-020-0717-9

摘要： The concentrating photovoltaic (CPV) systems are a promising technology to obtain clean energy. However, these systems are not equally convenient worldwide due to different climatic conditions. The main aim of this paper is to analyze energy and economic performances of a point-focus CPV system for a residential user when its installation site varies. Three locations, Riyadh, Copenhagen, and Palermo, characterized by very different weather conditions are chosen. A model that links the electrical power of a triple-junction (TJ) cell with its temperature and concentrated radiation incident on it is experimentally developed to evaluate the energy performance of the CPV system. A comparison of the three localities for typical winter and summer sunny days indicates that the higher values of the TJ cell temperature are reached in summer, over 70°C at Riyadh, and its electrical power is reduced compared to a winter day. In winter, a TJ cell in Riyadh supplies an electric power of about 20% higher than that in other two cities, while in summer, the maximum power is observed at Copenhagen. On the contrary, the electrical producibility also depends on the sunlight daily hours number during the year. Hence, considering the real distribution of direct normal irradiance (DNI) and the environmental temperature for each locality, a CPV system composed of modules of 90 cells adopted for a residential user is sized. The electric producibility of the CPV system, by varying its module number, is evaluated for different localities together with the optimal number of the modules which is able to maximize the investment profitability.

关键词： CPV system     point-focus     experimental model     energy and economic analysis    

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Substance flow analysis for an urban drainage system of a representative hypothetical city in China

Hua BAI, Siyu ZENG, Xin DONG, Jining CHEN

《环境科学与工程前沿（英文）》 2013年 第7卷 第5期   页码 746-755 doi: 10.1007/s11783-013-0551-y

摘要： This paper discusses the use of substance flow analysis (SFA) as a tool to support quantified research on urban drainage systems. Based on the principle of mass balance, a static substance flow model is established to describe and examine the routes and intensities of water, chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) for a representative hypothetical city (RH city) in China, which is a devised and scaled city using statistical characteristics of urban circumstances at the national level. It is estimated that the annual flux of water, COD, TN and TP through the urban drainage system in 2010 was 55.1 million m , 16037.3 t, 1649.5 t and 209.7 t, respectively. The effluent of wastewater treatment plant (WWTP) was identified as the most important pathway for pollutant emissions, which contributed approximately 60% of COD, 65% of TN and 50% of TP to receiving water. During the wastewater treatment process, 1.0 million m , 7042.5 t, 584.2 t and 161.4 t of the four studied substances had been transmitted into sludge, meanwhile 3813.0 t of COD and 394.0 t of TN were converted and emitted to the atmosphere. Compared with the representative hypothetical city of 2000, urban population and the area of urban built districts had expanded by approximately 90% and 80% respectively during the decade, resulting in a more than threefold increase in the input of substances into the urban drainage system. Thanks to the development of urban drainage systems, the total loads of the city were maintained at a similar level.

关键词： substance flow analysis (SFA)     urban drainage system     representative hypothetical city (RH city)     water pollution control    

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Simulation analysis of pressure regulation of hydraulic thrust system on a shield tunneling machine

Zhibin LIU, Haibo XIE, Huayong YANG

《机械工程前沿（英文）》 2011年 第6卷 第3期   页码 377-382 doi: 10.1007/s11465-011-0226-y

摘要：

Hydraulic thrust system is an important system in a shield tunneling machine. Pressure regulation of thrust cylinders is the most important function for thrust system during tunnel excavation. In this paper, a hydraulic thrust system is explained, and a corresponding simulation model is carried out in order to study the system characteristics. Pressure regulation of a certain group’s cylinders has little influence on regulation of the other groups’ cylinders. The influence will not affect the process much during tunnel excavation. Pump displacement may have a greater effect on pressure regulation and oil supply flow rate should be adaptive to the system’s demand. A exacting situation is simulated to explain how pressure regulation works during tunnel excavation.

关键词： tunnel     hydraulic thrust system     pressure regulation     simulation    

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Optimization model analysis of centralized groundwater source heat pump system in heating season

Shilei LU,Yunfang QI,Zhe CAI,Yiran LI

《能源前沿（英文）》 2015年 第9卷 第3期   页码 343-361 doi: 10.1007/s11708-015-0372-8

摘要： The ground-water heat-pump system (GWHP) provides a high efficient way for heating and cooling while consuming a little electrical energy. Due to the lack of scientific guidance for operating control strategy, the coefficient of performance (COP) of the system and units are still very low. In this paper, the running strategy of GWHP was studied. First, the groundwater thermal transfer calculation under slow heat transfixion and transient heat transfixion was established by calculating the heat transfer simulation software Flow Heat and using correction factor. Next, heating parameters were calculated based on the building heat load and the terminal equipment characteristic equation. Then, the energy consumption calculation model for units and pumps were established, based on which the optimization method and constraints were established. Finally, a field test on a GWHP system in Beijing was conducted and the model was applied. The new system operation optimization idea for taking every part of the GWHP into account that put forward in this paper has an important guiding significance to the actual operation of underground water source heat pump.

关键词： optimization model     groundwater source heat pump system     theoretical analysis     example verification     heating season    

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Water pumping analysis and experimental validation of beach well infiltration intake system in a seawatersource heat pump system

Huan ZHANG,Shu LIU,Xuejing ZHENG,Gaofeng CHEN

《能源前沿（英文）》 2015年 第9卷 第3期   页码 335-342 doi: 10.1007/s11708-015-0365-7

摘要： Based on energy conservation equation and Darcy’s law, a model of beach well infiltration intake system applied in a seawater source heat pump system was established. The model consists of the seawater seepage and the heat transfer process. A porous medium model in a software named FLUENT was applied to simulate the seepage and the heat transfer process. This model was also validated by field experiment conducted on the seashore in Tianjin, China. The maximum relative error between simulation results and experimental results was 2.1% (less than 5%), which was acceptable in engineering application. The porosity and coefficient of thermal conductivity of the aquifer soil were determined to be 0.49 W/(m·K) and 1.46 W/(m·K), respectively in the simulation. In addition, the influencing factors of pumping water of beach well were also analyzed. The pumping water was found to increase when the distance between the beach well and the impervious boundary becomes longer, when the distance between the beach well and the supplying water source shortens, when the diameter of the beach well enlarges, and the drawdown enlarges.

关键词： water pumping analysis     experimental validation     infiltration intake system     seawater source heat pump    

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Theory analysis and system identification methods on thermal dynamics characteristics of ballscrews

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

《机械工程前沿（英文）》 2008年 第3卷 第4期   页码 408-415 doi: 10.1007/s11465-008-0061-y

摘要： Empirical model of machine tools on thermal error has been widely researched, which can compensate for thermal error to some extent but not suitable for thermal dynamic errors produced by dynamic heat sources. The thermoelastic phenomenon of unidimensional heat transfer of ballscrews influenced by changeable heat sources is analyzed based on the theory of heat transfer. Two methods for system identification (the least square system identification and BP artificial neural network (ANN) system identification) are put forward to establish a dynamic characteristic model of thermal deformation of ballscrews. The model of thermal error of the axis in a feed system of DM4600 vertical miller is established with a fine identification effect. Comparing the results of the two identification methods, the BP ANN system identification is more precise than the least square system identification.

关键词： square system     network     vertical miller     transfer     ANN    

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Thermo-economic analysis of a direct supercritical CO electric power generation system using geothermal

《能源前沿（英文）》 2022年 第16卷 第2期   页码 246-262 doi: 10.1007/s11708-021-0749-9

摘要： A comprehensive thermo-economic model combining a geothermal heat mining system and a direct supercritical CO2 turbine expansion electric power generation system was proposed in this paper. Assisted by this integrated model, thermo-economic and optimization analyses for the key design parameters of the whole system including the geothermal well pattern and operational conditions were performed to obtain a minimal levelized cost of electricity (LCOE). Specifically, in geothermal heat extraction simulation, an integrated wellbore-reservoir system model (T2Well/ECO2N) was used to generate a database for creating a fast, predictive, and compatible geothermal heat mining model by employing a response surface methodology. A parametric study was conducted to demonstrate the impact of turbine discharge pressure, injection and production well distance, CO2 injection flowrate, CO2 injection temperature, and monitored production well bottom pressure on LCOE, system thermal efficiency, and capital cost. It was found that for a 100 MWe power plant, a minimal LCOE of $0.177/kWh was achieved for a 20-year steady operation without considering CO2 sequestration credit. In addition, when CO2 sequestration credit is $1.00/t, an LCOE breakeven point compared to a conventional geothermal power plant is achieved and a breakpoint for generating electric power generation at no cost was achieved for a sequestration credit of $2.05/t.

关键词： geothermal heat mining     supercritical CO2     power generation     thermo-economic analysis     optimization    

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Dynamics analysis of bladder-urethra system based on CFD

Qinghua JIN, Xiaojun ZHANG, Xiaoyang LI, Jianliu WANG,

《机械工程前沿（英文）》 2010年 第5卷 第3期   页码 336-340 doi: 10.1007/s11465-010-0027-8

摘要： A mathematical model for a bladder-urethra system can provide basic analysis for the disabled urethra closure of stress urinary incontinence (SUI) patients in a clinic. Based on computational fluid dynamics (CFD), we developed a three-dimensional urodynamic bladder-urethra system, which includes bladder, bladder neck, prostate, and urethra. The realistic recirculation process of the urinary bladder during the physiologic voiding process in conjunction with a flow simulation through the female urinary bladder and urethra is presented. The computational results show that a dead-water zone and the zone of secondary flow occur, independent of the shape of the prostatic urethra. For the pathological prostata, the extreme constriction of the prostatic urethra results in an additional wide-stretched dead-water zone. The simulation results does not only improve urinary incontinence surgery for clinicians, but can also provide a basis for theoretical analysis.

关键词： bladder-urethra system     stress urinary incontinence (SUI)     computational fluid dynamics (CFD)     urodynamics    

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Performance analysis of solar absorption-subcooled compression hybrid refrigeration system in subtropical

Xiangyang YE,Liming LIU,Zeyu LI

《能源前沿（英文）》 2019年 第13卷 第1期   页码 185-192 doi: 10.1007/s11708-017-0452-z

摘要： Solar absorption-subcooled compression hybrid refrigeration system is a new type of efficient and economical solar refrigeration device which always meets the demand of cooling load with the change of solar irradiance. The performance of the hybrid system is higher due to the improvement of evaporator temperature of absorption subsystem. But simultaneously, the variation of working process as well as performance is complicated since the absorption and compression subsystems are coupled strongly. Based on the measured meteorological data of Guangzhou, a subtropical city in south China, a corresponding parametric model has been developed for the hybrid refrigeration system, and a program written by Fortran has been used to analyze the performance of the hybrid system under different external conditions. As the condensation temperature ranges from 38°C to 50°C, the working time fraction of the absorption subsystem increases from 75% to 85%. Besides, the energy saving fraction also increases from 5.31% to 6.02%. The average COP of the absorption subsystem is improved from 0.366 to 0.407. However, when the temperature of the absorption increases from 36°C to 48°C, the average COP of hybrid system decreases from 2.703 to 2.312. Moreover, the working time fraction of the absorption subsystem decreases from 80% to 71.7%. The energy saving fraction falls from 5.67% to 5.08%. In addition, when the evaporate temperature increases from 4°C to 14°C, the average COP of the absorption subsystem decreases from 0.384 to 0.365. The work of the compressor decreases from 48.2 kW to 32.8 kW and the corresponding average COP of the absorption subsystem is improved from 2.591 to 3.082.

关键词： solar     absorption-subcooled     compression hybrid     dynamic simulation     performance analysis    

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Game theoretic analysis of environmental impact assessment system in China

CHENG Hongguang, PU Xiao, GONG Li, QI Ye

《环境科学与工程前沿（英文）》 2007年 第1卷 第4期   页码 448-453 doi: 10.1007/s11783-007-0071-8

摘要： Environmental impact assessment (EIA) system has been established in China since 1973. In present EIA cases, there are four participants in general: governments, enterprises, EIA organizations and the public. The public has held re

关键词： public     impact assessment     Environmental impact     general    

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Reliability analysis of the control system of large-scale vertical mixing equipment

YANG Mingjin, LI Xiwen, LI Shaoping, YANG Shuzi

《机械工程前沿（英文）》 2008年 第3卷 第2期   页码 133-138 doi: 10.1007/s11465-008-0037-y

摘要： The control system of vertical mixing equipment is a concentrate distributed monitoring system (CDMS). A reliability analysis model was built and its analysis was conducted based on reliability modeling theories such as the graph theory, Markov process, and redundancy theory. Analysis and operational results show that the control system can meet all technical requirements for high energy composite solid propellant manufacturing. The reliability performance of the control system can be considerably improved by adopting a control strategy combined with the hot spared redundancy of the primary system and the cold spared redundancy of the emergent one. The reliability performance of the control system can be also improved by adopting the redundancy strategy or improving the quality of each component and cable of the system.

关键词： composite     redundancy     monitoring     vertical     technical    

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Experimental investigation and feasibility analysis of a thermophotovoltaic cogeneration system in high-temperature

Jianxiang WANG, Hong YE, Xi WU, Hujun WANG, Xiaojie XU

《能源前沿（英文）》 2013年 第7卷 第2期   页码 146-154 doi: 10.1007/s11708-013-0253-y

摘要： The experimental - characteristics of a Si cell module in a thermophotovoltaic (TPV) system were investigated using SiC or Yb O radiator. The results demonstrate that the short-circuit current increases while the open-circuit voltage, along with the fill factor, decreases with the cell temperature when the radiator temperature increases from 1273 to 1573 K, leading to a suppressed increase of the output power of the system. The maximum output power density of the cell module is 0.05 W/cm when the temperature of the SiC radiator is 1573 K, while the electrical efficiency of the system is only 0.22%. The efficiency is 1.3% with a Yb O radiator at the same temperature, however, the maximum output power density drops to 0.03 W/cm . The values of the open-circuit voltage and the maximum output power obtained from the theoretical model conform to the experimental ones. But the theoretical short-circuit current is higher because of the existence of the contact resistance inside the cell module. In addition, the performance and cost of TPV cogeneration systems with the SiC or Yb O radiator using industrial high-temperature waste heat were analyzed. The system electrical efficiency could reach 3.1% with a Yb O radiator at 1573 K. The system cost and investment recovery period are 6732 EUR/kWel and 14 years, respectively.

关键词： thermophotovoltaic (TPV)     industrial waste heat     ytterbium oxide     system efficiency    

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标题 作者 时间 类型 操作

Reliability analysis of urban gas transmission and distribution system based on FMEA and correlation

Su LI,Weiguo ZHOU

期刊论文

Risk analysis methods of the water resources system under uncertainty

Zeying GUI,Chenglong ZHANG,Mo Li,Ping GUO

期刊论文

Last Planner System and Scrum: Comparative analysis and suggestions for adjustments

Roshan POUDEL, Borja GARCIA de SOTO, Eder MARTINEZ

期刊论文

Energy and economic analysis of a point-focus concentrating photovoltaic system when its installation

C. RENNO, A. PERONE

期刊论文

Substance flow analysis for an urban drainage system of a representative hypothetical city in China

Hua BAI, Siyu ZENG, Xin DONG, Jining CHEN

期刊论文

Simulation analysis of pressure regulation of hydraulic thrust system on a shield tunneling machine

Zhibin LIU, Haibo XIE, Huayong YANG

期刊论文

Optimization model analysis of centralized groundwater source heat pump system in heating season

Shilei LU,Yunfang QI,Zhe CAI,Yiran LI

期刊论文

Water pumping analysis and experimental validation of beach well infiltration intake system in a seawatersource heat pump system

Huan ZHANG,Shu LIU,Xuejing ZHENG,Gaofeng CHEN

期刊论文

Theory analysis and system identification methods on thermal dynamics characteristics of ballscrews

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

期刊论文

Thermo-economic analysis of a direct supercritical CO electric power generation system using geothermal

期刊论文

Dynamics analysis of bladder-urethra system based on CFD

Qinghua JIN, Xiaojun ZHANG, Xiaoyang LI, Jianliu WANG,

期刊论文

Performance analysis of solar absorption-subcooled compression hybrid refrigeration system in subtropical

Xiangyang YE,Liming LIU,Zeyu LI

期刊论文

Game theoretic analysis of environmental impact assessment system in China

CHENG Hongguang, PU Xiao, GONG Li, QI Ye

期刊论文

Reliability analysis of the control system of large-scale vertical mixing equipment

YANG Mingjin, LI Xiwen, LI Shaoping, YANG Shuzi

期刊论文

Experimental investigation and feasibility analysis of a thermophotovoltaic cogeneration system in high-temperature

Jianxiang WANG, Hong YE, Xi WU, Hujun WANG, Xiaojie XU

期刊论文