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Autonomous Multi-Factor Energy Flows Controller (AmEFC): Enhancing Renewable Energy Management with Intelligent Control Systems Integration
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作者 Dimitrios Vezeris Maria Polyzoi +2 位作者 Georgios Kotakis Pagona Kleitsiotou Eleni Tsotsopoulou 《Energy and Power Engineering》 2023年第11期399-442,共44页
The transition to sustainable energy systems is one of the defining challenges of our time, necessitating innovations in how we generate, distribute, and manage electrical power. Micro-grids, as localized energy hubs,... The transition to sustainable energy systems is one of the defining challenges of our time, necessitating innovations in how we generate, distribute, and manage electrical power. Micro-grids, as localized energy hubs, have emerged as a promising solution to integrate renewable energy sources, ensure energy security, and improve system resilience. The Autonomous multi-factor Energy Flow Controller (AmEFC) introduced in this paper addresses this need by offering a scalable, adaptable, and resilient framework for energy management within an on-grid micro-grid context. The urgency for such a system is predicated on the increasing volatility and unpredictability in energy landscapes, including fluctuating renewable outputs and changing load demands. To tackle these challenges, the AmEFC prototype incorporates a novel hierarchical control structure that leverages Renewable Energy Sources (RES), such as photovoltaic systems, wind turbines, and hydro pumps, alongside a sophisticated Battery Management System (BMS). Its prime objective is to maintain an uninterrupted power supply to critical loads, efficiently balance energy surplus through hydraulic storage, and ensure robust interaction with the main grid. A comprehensive Simulink model is developed to validate the functionality of the AmEFC, simulating real-world conditions and dynamic interactions among the components. The model assesses the system’s reliability in consistently powering critical loads and its efficacy in managing surplus energy. The inclusion of advanced predictive algorithms enables the AmEFC to anticipate energy production and consumption trends, integrating weather forecasting and inter-controller communication to optimize energy flow within and across micro-grids. This study’s significance lies in its potential to facilitate the seamless incorporation of RES into existing power systems, thus propelling the energy sector towards a more sustainable, autonomous, and resilient future. The results underscore the potential of such a system to revolutionize energy management practices and highlight the importance of smart controller systems in the era of smart grids. 展开更多
关键词 MICRO-GRID Smart Grid Interconnection Hybrid Renewable system energy flow Controller Battery Management Hydro Pump Off-Grid Solutions Ioniki Autonomous
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Over-limit risk assessment method of integrated energy system considering source-load correlation
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作者 Ying Wang Xiaojun Wang +2 位作者 Yizhi Zhang Yigang Zhang Zekai Xu 《Global Energy Interconnection》 EI CSCD 2023年第6期661-674,共14页
In an integrated energy system,source-load multiple uncertainties and correlations lead to an over-limit risk in operating state,including voltage,temperature,and pressure over-limit.Therefore,efficient probabilistic ... In an integrated energy system,source-load multiple uncertainties and correlations lead to an over-limit risk in operating state,including voltage,temperature,and pressure over-limit.Therefore,efficient probabilistic energy flow calculation methods and risk assessment theories applicable to integrated energy systems are crucial.This study proposed a probabilistic energy flow calculation method based on polynomial chaos expansion for an electric-heat-gas integrated energy system.The method accurately and efficiently calculated the over-limit probability of the system state variables,considering the coupling conditions of electricity,heat,and gas,as well as uncertainties and correlations in renewable energy unit outputs and multiple types of loads.To further evaluate and quantify the impact of uncertainty factors on the over-limit risk,a global sensitivity analysis method for the integrated energy system based on the analysis of covariance theory is proposed.This method considered the source-load correlation and aimed to identify the key uncertainty factors that influence stable operation.Simulation results demonstrated that the proposed method achieved accuracy to that of the Monte Carlo method while significantly reducing calculation time.It effectively quantified the over-limit risk under the presence of multiple source-load uncertainties. 展开更多
关键词 Probabilistic energy flow Polynomial chaos expansion CORRELATION Risk assessment Analysis of covariance
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A mass balanced model of trophic structure and energy flows of a semi-closed marine ecosystem 被引量:9
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作者 HAN Dongyan XUE Ying +1 位作者 ZHANG Chongliang REN Yiping 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第10期60-69,共10页
The marine ecosystem of the Jiaozhou Bay has degraded significantly in fisheries productivity and its ecological roles as spawning and nursery ground for many species of commercial importance has been declining in rec... The marine ecosystem of the Jiaozhou Bay has degraded significantly in fisheries productivity and its ecological roles as spawning and nursery ground for many species of commercial importance has been declining in recent years. A mass-balanced trophic model was developed using Ecopath with Ecosim to evaluate the trophic structure of the Jiaozhou Bay for improving ecosystem management. The model were parameterized based on the fisheries survey data in the Jiaozhou Bay in 2011, including 23 species groups and one detritus group according to their ecological roles. The trophic levels of these ecological groups ranged from 1(primary producers and detritus) to4.3(large demersal fishes). The estimated total system throughput was 12 917.10 t/(km^2·a), with 74.59% and25.41% contribution of the total energy flows from phytoplankton and detritus, respectively. Network analyses showed that the overall transfer efficiency of the ecosystem was 14.4%, and the mean transfer efficiency was 14.5%for grazing food chain and 13.9% for detritus food chain. The system omnivory index(SOI), Finn's cycled index(FCI) and connectance index(CI) were relatively low in this area while the total primary production/total respiration(TPP/TR) was high, indicating an immature and unstable status of the Jiaozhou Bay ecosystem. Mixed trophic impact analysis revealed that the cultured shellfish had substantial negative impacts on most functional groups. This study contributed to ecosystem-level evaluation and management planning of the Jiaozhou Bay ecosystem. 展开更多
关键词 Ecopath with Ecosim Jiaozhou Bay energy flow trophic structure
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Ecosystem Productivity and Energy Flow of Three-Hardwood Forest 被引量:1
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作者 陆兆华 柴瑞海 《Journal of Forestry Research》 SCIE CAS CSCD 1997年第1期20-22,共3页
The main characteristics of energy environment, energy products, primary productivity and basic process ofenergy flow for three-hardwood forest(Juglans mandshurica, Fraxinus mandshurica, and Phellodendron amurense) we... The main characteristics of energy environment, energy products, primary productivity and basic process ofenergy flow for three-hardwood forest(Juglans mandshurica, Fraxinus mandshurica, and Phellodendron amurense) werestudied. The research was mainly hased on the thcory and method of community energetics, dealing with fixed position,quantitative test and expcrimental analysis. The time-space dynamics of sun-radiation in three-hardwood forest were measured and the energy compartment model was set up. his rescarch work provided a scientitic basis for the exploitation, utilization and management of three-hardtwood forest. 展开更多
关键词 PRODUCTIVITY energy flow Three-hardwood forest Compartment model energy environment
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A Study on Alien Invasive Plants from the Interactive Mechanism between Species Niche and Material/Energy Flow 被引量:3
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作者 陈剑 喻庆国 杨宇明 《Agricultural Science & Technology》 CAS 2011年第1期14-19,共6页
[Objective]This study was to reveal the essence of mechanism about how the alien invasive plants spread.[Method]Species niche and material/energy flow were used as basic research indicators to analyze the intrinsic me... [Objective]This study was to reveal the essence of mechanism about how the alien invasive plants spread.[Method]Species niche and material/energy flow were used as basic research indicators to analyze the intrinsic mechanism of alien plants invasion.[Result]Most of the invasive plants have not been explicitly defined and their effective control methods not brought forward.[Conclusion]Overrun of alien invasive plants depends on whether the niche of a species could be continuously met at spatial level.Based on this we put forward corresponding control measures,proposed an assumption to establish a cylinder-network model and discussed the definition of alien invasive plants. 展开更多
关键词 Species niche Material/energy flow Alien invasive plants Interactive mechanism
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Impact of material and energy flow variation-based iron /steel ratio on production cost
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作者 陆彪 陈光 +2 位作者 陈德敏 虞维平 丁毅 《Journal of Southeast University(English Edition)》 EI CAS 2015年第3期375-379,共5页
This paper establishes a model for the production cost of iron and steel enterprise.The variation rule of the production cost versus the iron/steel ratio for two cases, namely,fixed steel production and a fixed amount... This paper establishes a model for the production cost of iron and steel enterprise.The variation rule of the production cost versus the iron/steel ratio for two cases, namely,fixed steel production and a fixed amount of molten iron,is analyzed,and the concept of a steel scrap threshold price is proposed.According to the analysis results,when the steel scrap unit price exceeds the steel scrap threshold price, an increase in the iron/steel ratio can reduce the production cost,and vice versa.When the gap between the steel scrap unit price and the steel scrap threshold price is relatively large, the impact of the iron/steel ratio on the production cost is more prominent.According to the calculation example,when steel production is fixed (284 358 t/month)and the steel scrap unit price is 263.2 yuan/t more than the steel scrap threshold price,an increase of 0.01 in the iron/steel ratio causes a monthly production cost reduction of approximately 750 000 yuan (2.63 yuan/t).When the amount of molten iron is fixed (270 425 t/month)and the steel scrap unit price is 140.7 yuan/t more than the threshold price,an increase of 0.01 in the iron/steel ratio causes a monthly production cost reduction of approximately 430 000 yuan (1.5 yuan/t).The results indicate that iron and steel enterprise should adjust the production strategy in time when the scrap price fluctuates, and then the production cost will be reduced. 展开更多
关键词 iron/steel ratio material flow energy flow model of production cost steel scrap threshold price
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Energy flow problem solution based on state estimation approaches and smart meter data 被引量:1
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作者 Andrew V.Pazderin Ilya D.Polyakov Vladislav O.Samoylenko 《Global Energy Interconnection》 EI CAS CSCD 2022年第5期551-563,共13页
Accurate electric energy(EE)measurements and billing estimations in a power system necessitate the development of an energy flow distribution model.This paper summarizes the results of investigations on a new problem ... Accurate electric energy(EE)measurements and billing estimations in a power system necessitate the development of an energy flow distribution model.This paper summarizes the results of investigations on a new problem related to the determination of EE flow in a power system over time intervals ranging from minutes to years.The problem is referred to as the energy flow problem(EFP).Generally,the grid state and topology may fluctuate over time.An attempt to use instantaneous(not integral)power values obtained from telemetry to solve classical electrical engineering equations leads to significant modeling errors,particularly with topology changes.A promoted EFP model may be suitable in the presence of such topological and state changes.Herein,EE flows are determined using state estimation approaches based on direct EE measurement data in Watt-hours(Volt-ampere reactive-hours)provided by electricity meters.The EFP solution is essential for a broad set of applications,including meter data validation,zero unbalance EE billing,and nontechnical EE loss check. 展开更多
关键词 Automatic meter reading Advanced metering infrastructure energy flow distribution Electricity losses energy measurements State estimation.
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Energy Flow of Macrozoobenthos Community in an Algal Lake,Houhu Lake(Wuhan,China) 被引量:1
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作者 闫云君 梁彦龄 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2003年第3期229-244,共16页
Energy flow of the macrozoobenthic community in an algal lake, Houhu Lake (Wuhan, China) was investigated from April, 1996 to March, 1997. The estimated consumption of the community was 2522.7 kJ/(m 2·a); defecat... Energy flow of the macrozoobenthic community in an algal lake, Houhu Lake (Wuhan, China) was investigated from April, 1996 to March, 1997. The estimated consumption of the community was 2522.7 kJ/(m 2·a); defecation was 2049.1 kJ/(m 2·a); metabolism 371.2 kJ/(m 2·a); excretion 34.7 kJ/(m 2·a) and production 67.7 kJ/(m 2·a). The assimilation rate of the community was 19%; and 81% of its ingestion was defecated. The computed net growth efficiency was 14%, much lower than most reported values, which meant that the macrozoobenthic community in Houhu Lake utilized food less effectively. 展开更多
关键词 energy flow macrozoobenthic community Houhu Lake
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Improved Soft Abrasive Flow Finishing Method Based on Turbulent Kinetic Energy Enhancing 被引量:8
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作者 Jun LI Shiming JI Dapeng TAN 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第2期301-309,共9页
Soft abrasive flow(SAF) finishing can process the irregular geometric surfaces, but with the matter of low processing efficiency. To address the issue, an improved SAF finishing method based on turbulent kinetic ene... Soft abrasive flow(SAF) finishing can process the irregular geometric surfaces, but with the matter of low processing efficiency. To address the issue, an improved SAF finishing method based on turbulent kinetic energy enhancing is proposed. A constrained flow passage with serration cross-section is constructed to increase the turbulence intensity. Taking the constrained flow passage as the objective, a two-phase fluid dynamic model is set up by using particle trajectory model and standard k-ε turbulence model, and the flow field characteristics of the flow passage are acquired. The numerical results show that the serration flow passage can enhance the turbulence intensity, uniform the particles distribution, and increase the particle concentration near the bottom wall. The observation results by particle image velocimetry(PIV) show that the internal vortex structures are formed in flow passage, and the abrasive flow takes on turbulence concentrating phenomenon in near-wall region. The finishing experiments prove that the proposed method can obtain better surface uniformity, and the processing efficiency can be improved more 35%. This research provides an abrasive flow modeling method to reveal the particle motion regulars, and canoffer references to the technical optimization of fluid-based precision processing. 展开更多
关键词 Soft abrasive flow Serration flow passage ·Kinetic energy enhancing Particle image velocimetry
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Super energy flows in a waveguide filled with air and left-handed materials 被引量:1
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作者 余观夏 崔铁军 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第1期164-169,共6页
The phenomena of super energy flows are studied theoretically and numerically in a parallel-plate waveguide which is filled with two layered equally-thick different media, i.e. air and specific left-handed materials ... The phenomena of super energy flows are studied theoretically and numerically in a parallel-plate waveguide which is filled with two layered equally-thick different media, i.e. air and specific left-handed materials (LHM) with εr1 = -1/(1 +δ) +iγ and μr1 = -(1 + δ) + iγ. In this special waveguide, two-directional super-energy flows are excited by a three-dimensional horizontal electric dipole at the same time, which has transmission patterns different from those of two-dimensional source and three-dimensional vertical electric dipole. We also show that the retardation and loss in LHM are sensitive to the amplitude of super power densities, and the dimensions of waveguide determine the propagating modes, which makes super energy flows more practical. 展开更多
关键词 super energy flows left-handed materials
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Experimental study on the energy dissipation characteristics of debris flow deceleration baffles 被引量:3
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作者 WANG Fei CHEN Xiao-qing CHEN Jian-gang 《Journal of Mountain Science》 SCIE CSCD 2017年第10期1951-1960,共10页
Debris flow can cause serious damages to roads, bridges, buildings and other infrastructures.Arranging several rows of deceleration baffles in the significant influence on the mobility and deposition characteristic of... Debris flow can cause serious damages to roads, bridges, buildings and other infrastructures.Arranging several rows of deceleration baffles in the significant influence on the mobility and deposition characteristic of debris flow. The deposit amount first increased then decreased when the flow density rises,flow path can reduce the flow velocity and ensure better protection of life and property. In debris flow prevention projects, deceleration baffles can effectively reduce the erosion of the debris flow and prolong the running time of the drainage channel.This study investigated the degree to which a 6 m long flume and three rows of deceleration baffles reduce the debris flow velocity and affect the energy dissipation characteristics. The influential variables include channel slope, debris flow density, and spacing between baffle rows. The experimental results demonstrated that the typical flow pattern was a sudden increase in flow depth and vertical proliferation when debris flow flows through the baffles. Strong turbulence between debris flow and baffles can contribute to energy dissipation and decrease the kinematic velocity considerably. The results showed that the reduction ratio of velocity increased with the increase in debris flow density,channel slope and spacing between rows. Tests phenomena also indicated that debris flow density hasand the deposit amount of debris flow density of 1500kg/m^3 reached the maximum when the experimental flume slope is 12°. 展开更多
关键词 Debris flow Drainage channel Baffles energy dissipation flow density
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Renewable and Nonrenewable Energy Flow Resiliency for Day-to-Day Production and Consumption 被引量:2
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作者 Bahman Zohuri Farhang Mossavar-Rahmani Masoud Moghaddam 《Journal of Energy and Power Engineering》 2022年第1期13-18,共6页
Energy resilience is about ensuring a business and end-use consumers have a reliable,regular supply of energy and contingency measures in place in the event of a power failure,generating a source of power such as elec... Energy resilience is about ensuring a business and end-use consumers have a reliable,regular supply of energy and contingency measures in place in the event of a power failure,generating a source of power such as electricity for daily needs from an uninterrupted source of energy no matter either renewable or nonrenewable.Causes of resilience issues include power surges,weather,natural disasters,or man-made accidents,and even equipment failure.The human operational error can also be an issue for grid-power supply to go down and should be factored into resilience planning.As the energy landscape undergoes a radical transformation,from a world of large,centralized coal plants to a decentralized energy world made up of small-scale gas-fired production and renewables,the stability of electricity supply will begin to affect energy pricing.Businesses must plan for this change.The challenges that the growth of renewables brings to the grid in terms of intermittency mean that transmission and distribution costs consume an increasing proportion of bills.With progress in the technology of AI(Artificial Intelligence)integration of such progressive technology in recent decades,we are improving our resiliency of energy flow,so we prevent any unexpected interruption of this flow.Ensuring your business is energy resilient helps insulate against price increases or fluctuations in supply,becoming critical to maintaining operations and reducing commercial risk.In the form short TM(Technical Memorandum),this paper covers this issue. 展开更多
关键词 Resilience system energy flow energy storage energy grid BI(business intelligence) AI cyber security decision making in real-time machine learning and deep learning BD(big data)and cloud-based servers for repository and storage of data
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Quasi-40-Day Oscillation and Its Teleconnection Structure together with the Possible Dependence on Conversion of Barotropic Unstable Energy of Temporal Mean Flow 被引量:1
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作者 徐建军 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1993年第2期193-200,共8页
A study is made of the distribution of the diagnostic quantity vector E and the teleconnection structure of 30-50 (quasi-40) day oscillation, together with the dependence on the conversion of barotropic unstable energ... A study is made of the distribution of the diagnostic quantity vector E and the teleconnection structure of 30-50 (quasi-40) day oscillation, together with the dependence on the conversion of barotropic unstable energy of mean flow in terms of ECWMF daily 500 hPa grid data in winter, indicating that the energy transportation is closely associated with the westerly jet position, with zonal (meridional) propagation in the strong (weak) wind region, that considerable conversion of barotropic energy occurs at the jet exit region where low-frequency oscillation gains energy from the mean flow, leading to maximum kinetic energy for the oscillation observed there, which is marked by evident barotropy in striking contrast to the baroclinicity at low latitudes and that the teleconnection core is related to the center of action in the atmosphere and bound up with the pattern of the west wind. 展开更多
关键词 Quasi-40-Day Oscillation and Its Teleconnection Structure together with the Possible Dependence on Conversion of Barotropic Unstable energy of Temporal Mean flow
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Dual-radiation-chamber coordinated overall energy efficiency scheduling solution for ethylene cracking process regarding multi-parameter setting and multi-flow allocation
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作者 Di Meng Cheng Shao Li Zhu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第6期180-197,共18页
Ethylene cracking process is the core production process in ethylene industry,and is paid more attention to reduce high energy consumption.Because of the interdependent relationships between multi-flow allocation and ... Ethylene cracking process is the core production process in ethylene industry,and is paid more attention to reduce high energy consumption.Because of the interdependent relationships between multi-flow allocation and multi-parameter setting in cracking process,it is difficult to find the overall energy efficiency scheduling for the purpose of saving energy.The traditional scheduling solutions with optimal economic benefit are not applicable for energy efficiency scheduling issue due to the neglecting of recycle and lost energy,as well as critical operation parameters as coil outlet pressure(COP)and dilution ratio.In addition,the scheduling solutions mostly regard each cracking furnace as an elementary unit,regardless of the coordinated operation of internal dual radiation chambers(DRC).Therefore,to improve energy utilization and production operation,a novel energy efficiency scheduling solution for ethylene cracking process is proposed in this paper.Specifically,steam heat recycle and exhaust heat loss are considered in cracking process based on 6 types of extreme learning machine(ELM)based cracking models incorporating DRC operation and three operation parameters as coil outlet temperature(COT),COP,and dilution ratio according to semi-mechanism analysis.Then to provide long-term decision-making basis for energy efficiency scheduling,overall energy efficiency indexes,including overall output per unit net energy input(OONE),output-input ratio per unit net energy input(ORNE),exhaust gas heat loss ratio(EGHL),are designed based on input-output analysis in terms of material and energy flows.Finally,a multiobjective evolutionary algorithm based on decomposition(MOEA/D)is employed to solve the formulated multi-objective mixed-integer nonlinear programming(MOMINLP)model.The validities of the proposed scheduling solution are illustrated through a case study.The scheduling results demonstrate that an optimal balance between multi-flow allocation,multi-parameter setting,and DRC coordinated operation is reached,which achieves 3.37%and 2.63%decreases in net energy input for same product output and conversion ratio,as well as the 1.56%decrease in energy loss ratio. 展开更多
关键词 Ethylene cracking process energy efficiency scheduling Overall energy efficiency indexes Dual radiation chamber Multiple operation parameters Multiple energy flows
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Energy flow in Branchiura sowerbyi (Oligochaeta: tubificidae) in a shallow macrophyte-dominated lake, Biandantang Lake
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作者 闫云君 梁彦龄 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2004年第4期403-407,共5页
The energy flow of Branchiura sowerbyi was studied for the first time in China in a shallow macrophytic lake, Biandantang Lake, Hubei Province. The energy flow was calculated from the measurement of flesh production (... The energy flow of Branchiura sowerbyi was studied for the first time in China in a shallow macrophytic lake, Biandantang Lake, Hubei Province. The energy flow was calculated from the measurement of flesh production (12.5241kJ/m2a), egestion (517.7302kJ/m2a), metabolism (38.3273 kJ/m2a), and excretion (4.3798kJ/m2a). The net growth efficiency of the species is about 22.7%, which accords well with the generally reported value for oligochaetes. In addition, the relationship between starvation respiration (R, mgO2/ind穌), wet weight (Ww, mg) and temperature (T, C) were also measured, with the regression function being R=0.008 Ww0.736 e0.050T. 展开更多
关键词 Biandantang Lake energy flow Branchiura sowerbyi
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ENERGY FLOW OF BELLAMYA AERUGINOSA IN A SHALLOW ALGAL LAKE, HOUHU LAKE (WUHAN, CHINA)
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作者 闫云君 梁彦龄 王洪铸 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2001年第3期243-248,共6页
The energy budget of Bellamya earuginosa in a shallow algal lake, Houhu Lake (Wuhan, China) was investigated by the measurement of flesh production (32.8kJ/(m 2·a)), egestion (337.7 kJ/(m 2·a)), metabolism (... The energy budget of Bellamya earuginosa in a shallow algal lake, Houhu Lake (Wuhan, China) was investigated by the measurement of flesh production (32.8kJ/(m 2·a)), egestion (337.7 kJ/(m 2·a)), metabolism (246.7 kJ/(m 2·a)), and estimation of excretion (21.4kJ/(m 2·a)). The net growth efficiency of the species is about 10.9%, which accords with the generally reported value for gastropods. In addition, the relationships between starvation respiration ( R , mgO 2/(Ind·d)), body weight ( Wd , mg in dry wt) and temperature ( T , ℃) were also determined. The regression equation R =0.044 Wd 0.537 e 0.061T was obtained by the least square method, The measured SDA of the species is 26.51% of its gross metabolism. 展开更多
关键词 Houhu Lake energy flow Bellamya aeruginosa
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Quantitative model of trophic interactions in Beibu Gulf ecosystem in the northern South China Sea 被引量:5
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作者 CHEN Zuozhi QIU Yongsong JIA Xiaoping 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2006年第3期116-124,共9页
A mass-balanced model was constructed to determine the flow-energy in a community of fishes and invertebrates in the Beibu Gulf, northern South China Sea using Ecopath and Ecosim software. Input parameters were taken ... A mass-balanced model was constructed to determine the flow-energy in a community of fishes and invertebrates in the Beibu Gulf, northern South China Sea using Ecopath and Ecosim software. Input parameters were taken from the literature, except for the biomass of fish groups which was obtained from trawl surveys during October 1997 to May 1999 in the study area. The model consisted of 16 functional groups (boxes), including one marine mammal and seabirds, each representing organisms with a similar role in the food web, and only covered the main trophic flow in the Beibu Gulf ecosystem. The results showed that the food web of Beibu Gulf was dominated by the detrital path and benthic invertebrates played a significant role in transferring energy from the detritus to higher trophic levels; phytoplankton was a primary producer and most utilized as a food source. Fractional trophic levels ranged from 1.0 to 4.08 with marine mammals occupying the highest trophic level. Using network analysis, the system network was mapped into a linear food chain and six discrete trophic levels were found with a mean transfer efficiency of 16.7% from the detritus, 16.2% from the primary producer within the ecosystem. The biomass density of the commercially utilized species estimated by the model is 8.46 t/km^2, only O. 48% of the net primary production. 展开更多
关键词 trophic dynamics modeling energy flow network analysis Beibu Gulf ecosystem
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Generalised energy conservation law for chaotic phenomena 被引量:4
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作者 Jing-Tang Xing 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2019年第6期1257-1268,共12页
Chaotic phenomena are increasingly being observed in all fields of nature,where investigations reveal that a natural phe nomenon exhibits nonlinearities and attempts to reveal their deep underlying mechanisms.Chaos is... Chaotic phenomena are increasingly being observed in all fields of nature,where investigations reveal that a natural phe nomenon exhibits nonlinearities and attempts to reveal their deep underlying mechanisms.Chaos is normally understood as“a state of disorder”,for which there is as yet no universally accepted mathematical definition.A commonly used concept states that,for a dynamical system to be classified as chaotic,it must have the following properties:be sensitive to initial conditions,show topological transitivity,have densely periodical orbits etc.Revealing the rules that govern chaotic motion is thus an important unsolved task for exploring nature.W e present herein a generalised energy conservation law governing chaotic phenomena.Based on two scalar variables,viz.generalised potential and kinetic energies defined in the phase space describing nonlinear dynamical systems,we find that chaotic motion is periodic motion with infinite time period whose time-averaged generalised potential and kinetic energies are conserved over its time period.This implies that,as the averaging time is increased,the time-averaged generalised potential and kinetic energies tend to constants while the time-averaged energy flows,i.e.,their rates of change with time,tend to zero.Numerical simulations on reported chaotic motions,such as the forced van der Pol system,forced Duffing system,forced smooth and discontinuous oscillator,Lorenz’s system,and Rossler's system,show the above conclusions to be correct according to the results presented herein.This discovery may indicate that chaotic phenomena in nature could be controlled because,even though their instantaneous states are disordered,their long-time averages can be predicted. 展开更多
关键词 CHAOS Generalised energy Generalised energy conservation Nonlinear dynamical systems energy flow theory
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A preliminary snapshot of the trophic model and ecosystem attributes of Kaptai reservoir ecosystem, Bangladesh 被引量:1
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作者 Mst Halima KHATUN Partho Protim BARMAN +3 位作者 YI Jundong Saymuna Tarin LUPA Md Mahiuddin ZAHANGIR Qun LIU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2021年第1期223-241,共19页
A mass-balanced Ecopath model presents a quantitative description of the trophic structure,fl ow of energy and trophic interaction among ecological groups of an ecosystem.The Ecopath with Ecosim(EwE)modeling program(V... A mass-balanced Ecopath model presents a quantitative description of the trophic structure,fl ow of energy and trophic interaction among ecological groups of an ecosystem.The Ecopath with Ecosim(EwE)modeling program(Version 6.5)was used to develop a preliminary trophic model for a tropical freshwater reservoir.The total fi sh biomass was 6.245 t/km 2 and the highest trophic level of the reservoir was 3.362(for snakehead).The ecosystem is phytoplankton based because primary producers originated 68%and detritus originated 32%of the total fl ow from lower trophic level.The gross effi ciency of the fi shery was 0.004,suggesting the ineffi ciency of the system.The positive eff ect of phytoplankton and detritus on most of the other groups were evident from mixed trophic analysis while moderately higher ecotrophic effi ciency(EE)of phytoplankton shows the ecosystem’s potential bottom-up control.The competition for the same resources among diff erent groups was also obvious.The ratio of primary production/respiration(1.969)suggests that the ecosystem is at the developing stage and utmost contemplation should be given to concerned human activities.The low value of relative ascendancy(30.13)and overhead(69.87)reveals the stability of the ecosystem and some degrees of maturity.It also predicts the presence of signifi cant strength in reserve of the system to withstand or overcome any perturbation.However,ecologically sustainable resource management plans should be implemented to ensure the sustainability of this reservoir resources. 展开更多
关键词 ECOPATH Kaptai reservoir trophic interaction transfer effi ciency energy flow
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Design aspect of a novel L-shaped pulsed column for liquid–liquid extraction applications: Energy consumption and the characteristics velocity concept 被引量:3
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作者 Pouria Amani Elham Mohammadi Sahar Akhgar 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第4期723-730,共8页
This article deals with the evaluation of the consumption of energy for a steady state solvent extraction in a novel L-shaped pulsed sieve-plate column, which is highly required for design and optimization of the peri... This article deals with the evaluation of the consumption of energy for a steady state solvent extraction in a novel L-shaped pulsed sieve-plate column, which is highly required for design and optimization of the periodic flow processes for industrial applications. In this regard, a comprehensive evaluation on the energy consumption in case of a pulsed flow for three different chemical systems is conducted and besides the influence of pulsation intensity, the effect of geometrical parameters including the plate spacing and the plate free area is investigated as well. Moreover, the concept of characteristic velocity models at flooding points is evaluated with respect to the variation of pressure drop along the column at different operational conditions. 展开更多
关键词 Solvent extraction Pulsed plate column Pressure drop energy consumption Pulsed flow Characteristic velocity
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