Battery energy storage systems(BESSs)are widely used in smart grids.However,power consumed by inner impedance and the capacity degradation of each battery unit become particularly severe,which has resulted in an incre...Battery energy storage systems(BESSs)are widely used in smart grids.However,power consumed by inner impedance and the capacity degradation of each battery unit become particularly severe,which has resulted in an increase in operating costs.The general economic dispatch(ED)algorithm based on marginal cost(MC)consensus is usually a proportional(P)controller,which encounters the defects of slow convergence speed and low control accuracy.In order to solve the distributed ED problem of the isolated BESS network with excellent dynamic and steady-state performance,we attempt to design a proportional integral(PI)controller with a reset mechanism(PI+R)to asymptotically promote MC consensus and total power mismatch towards 0 in this paper.To be frank,the integral term in the PI controller is reset to 0 at an appropriate time when the proportional term undergoes a zero crossing,which accelerates convergence,improves control accuracy,and avoids overshoot.The eigenvalues of the system under a PI+R controller is well analyzed,ensuring the regularity of the system and enabling the reset mechanism.To ensure supply and demand balance within the isolated BESSs,a centralized reset mechanism is introduced,so that the controller is distributed in a flow set and centralized in a jump set.To cope with Zeno behavior and input delay,a dwell time that the system resides in a flow set is given.Based on this,the system with input delays can be reduced to a time-delay free system.Considering the capacity limitation of the battery,a modified MC scheme with PI+R controller is designed.The correctness of the designed scheme is verified through relevant simulations.展开更多
Deep-Litter System is a high yield approach to raise swine with pollution free in a lower cost. In the research, based on the heat stress in summer caused by fermentation, three temperature-control systems were design...Deep-Litter System is a high yield approach to raise swine with pollution free in a lower cost. In the research, based on the heat stress in summer caused by fermentation, three temperature-control systems were designed, including natural ventilation through transoms, forced ventilation via fans, and cooling by hyperbaric spray system. Specifically, the latter intermittent auto-pressurized spray system developed in our lab, which could spray successively via pressure from storage tubes without wetting the fermentation bed, is suitable for the promotion with the deep-litter technology in rural regions , since the power consumption is only 1 kwh per day.展开更多
This study was designed to find out an optimised planting system of reducing non-point (source) pollution by analyzing the reasons and the factors of influence non-point pollution in farmland of Erhai Lake basin. Th...This study was designed to find out an optimised planting system of reducing non-point (source) pollution by analyzing the reasons and the factors of influence non-point pollution in farmland of Erhai Lake basin. The results showed that incomes, residual nitrogen in soil, and the loss of nitrogen in surface water in rice-garlic system were higher than those in rice-fava bean system. There were positive correlations between the nitrogen loss of farmland, nitrogen inputs, residual nitrogen in soil, and incomes of farmland. Economic benefits and environment benefits are both appropriate, if the area of rice-garlic system would be reduced to 53% and the area of rice-fava bean system increased to 36% of total cropping area in the investigated watershed. Adjustment of planting structure and introduction of reasonable rotation systems is considered an effective measure of controlling agricultural non-point pollution in watersheds of Erhai Lake.展开更多
Rice-duck (RD) and rice-fish (RF) ecological systems are major complex planting and breeding models of rice paddy fields in southern China. Studying the methane (CH4) and nitrous oxide (N2O) emissions and thei...Rice-duck (RD) and rice-fish (RF) ecological systems are major complex planting and breeding models of rice paddy fields in southern China. Studying the methane (CH4) and nitrous oxide (N2O) emissions and their economic value from these two ecosystems can provide theoretical and practical basis for further development and utilization of these classical agricultural techniques. CH4 and N2O emissions from RD and RF ecological systems were measured in situ by using static chambers technique. Using global warming potentials (GWPs), we assessed the greenhouse effect of CH4 and N2O and their economic value. Results showed that the peaks of CH4 emission fluxes from RD and RF appeared at full tillering stage and at heading stage, and the average emission fluxes were significantly (P〈 0.05) lower than that from CK. N2O fluxes remained low when the field is flooded and high after draining the water. Compared with CK, the total amount of N2O emissions was significantly (P〈0.05) higher and slightly lower than those from RD and RF, respectively. In 2006 and 2007, the total greenhouse effect of CH4 and N20 from RD and RF were 4 728.3 and 4 611 kg CO2 ha^-1, 4 545 and 4 754.3 kg CO2 ha^-1, respectively. The costs of greenhouse effect were 970.89 and 946.81 RMB yuan ha^-1, and 933.25 and 976.23 RMB yuan ha^-1, respectively, which were significant lower than those from CK (5 997.6 and 5 391.5 RMB yuan ha^-1). Except for the environment cost of CH4 and N2O, the economic benefits from RD and RF were 2 210.64 and 4 881.92 RMB yuan ha^-1; 3 798.37 and 5 310.64 RMB yuan ha^-1, respectively, higher than those from CK. Therefore, RD and RF complex ecological planting and breeding models can effectively decrease and control CH4 and N2O emissions, and they are two of the effective strategies to reduce greenhouse gases from rice paddy fields and contribute in alleviating global warming. Thus, their adoption is important to the environment together with their economy benefits.展开更多
Economic analysis of different diversified rotational cropping systems under Farmers' package/practices and improved package/practices was conducted in Birbhum district, West Bengal, located in the red and lateritic ...Economic analysis of different diversified rotational cropping systems under Farmers' package/practices and improved package/practices was conducted in Birbhum district, West Bengal, located in the red and lateritic belt of lower Gangetic plain of eastern lndia. Diversified triple cropping systems (peanut-brinjal+brinjal, rice-potato-pumpkin, and cucumber-cabbage-basella) required higher cost for cultivation, but also produced higher rice equivalent yield, higher net return and higher return rupee1 invested in both management practices. Considering the resource-ability and risk-bearing capacity, and net return and return rupee^-1 (RPR) invested, these cropping systems can be recommended for resource-rich farmers. Rice-rapeseed-cowpea, rice-wheat-green gram and radish-tomato-amaranthus systems profitable. These cropping systems can be required less inputs for cultivation, were less risky, and economically viable and recommended for resource-poor farmers. Peanut-brinjal + brinjal-okra-chilli + chilli-cucumber-cabbage-basella system was the best among all the 3-year rotational systems in respect to RPR in both management practices. This rotational system will be suitable for resource-rich farmers. Vegetable-based rotational systems (ridge gourd-marigold-okra-black gram-pointed gourd + pointed gourd-radish-tomato-amaranthus) or rice-based rotational system (rice-wheat-green gram-rice-rapeseed-cowpea-rice-potato-pumpkin) also found to be suitable to increase the profitability and system sustainability. These cropping systems can be recommended for all groups of farmers.展开更多
Extensive research work including multiple methodologies and numerous simulations have been completed in order to determine the economic effectiveness of employing CHP at commercial and residential sites. In contrast ...Extensive research work including multiple methodologies and numerous simulations have been completed in order to determine the economic effectiveness of employing CHP at commercial and residential sites. In contrast to the above, very few attempts have been made to develop methodologies to study the feasibility of CHP systems at industrial manufacturing facilities. As a result, practical opportunities for CHP at industrial sites are often not realized or even investigated. It follows that there is a need in the CHP related literature for an analysis that is explicit and yet general enough to determine the economic viability and potential for success of CHP systems at industrial manufacturing facilities. Therefore, the purpose of this paper is to clearly outline a methodology to determine the economic effectiveness of installation and operation of a CHP system at industrial facilities that have a need for space or process heating in the form of steam. The effect on the CHP system economic performance of several parameters, such as the project payback, internal rate of return, net present value, etc., are considered in the proposed methodology. The applicability and generality of the methodology is illustrated by examples including four different manufacturing facilities. The effects of the variability of factors such as annual facility operational hours during which both process heat and electricity are needed, facility average hourly thermal load, cost of utility supplied electricity, and CHP fuel type and associated fuel cost, on the outcome of the economic analysis are also examined.展开更多
In this article,an approach for economic performance assessment of model predictive control(MPC) system is presented.The method builds on steady-state economic optimization techniques and uses the linear quadratic Gau...In this article,an approach for economic performance assessment of model predictive control(MPC) system is presented.The method builds on steady-state economic optimization techniques and uses the linear quadratic Gaussian(LQG) benchmark other than conventional minimum variance control(MVC) to estimate the potential of reduction in variance.The LQG control is a more practical performance benchmark compared to MVC for performance assessment since it considers input variance and output variance,and it thus provides a desired basis for determining the theoretical maximum economic benefit potential arising from variability reduction.Combining the LQG benchmark directly with benefit potential of MPC control system,both the economic benefit and the optimal operation condition can be obtained by solving the economic optimization problem.The proposed algorithm is illustrated by simulated example as well as application to economic performance assessment of an industrial model predictive control system.展开更多
An economic topology can have many uses to the academician, student and practitioner. Refining a topology of economic systems helps to bring together seemingly disparate characteristics and to point out potential long...An economic topology can have many uses to the academician, student and practitioner. Refining a topology of economic systems helps to bring together seemingly disparate characteristics and to point out potential long run trends. The progression of economic systems over time and also brief explanations of each system are given. We argue that most modem economic systems have some remnants of earlier forms, that is, most economies today are some mixture of what might be considered pure systems. Measurable characteristics to identify a particular system are developed that allows progress to or from a particular classification to be charted for individual countries.展开更多
By virtue of alternating direction method of multipliers(ADMM), Newton-Raphson method, ratio consensus approach and running sum method, two distributed iterative strategies are presented in this paper to address the e...By virtue of alternating direction method of multipliers(ADMM), Newton-Raphson method, ratio consensus approach and running sum method, two distributed iterative strategies are presented in this paper to address the economic dispatch problem(EDP) in power systems. Different from most of the existing distributed ED approaches which neglect the effects of packet drops or/and time delays, this paper takes into account both packet drops and time delays which frequently occur in communication networks. Moreover, directed and possibly unbalanced graphs are considered in our algorithms, over which many distributed approaches fail to converge. Furthermore, the proposed schemes can address the EDP with local constraints of generators and nonquadratic convex cost functions, not just quadratic ones required in some existing ED approaches. Both theoretical analyses and simulation studies are provided to demonstrate the effectiveness of the proposed schemes.展开更多
Since the late 1950’s, the Malaysian human population has nearly quadrupled, increasing pressure on natural resource exploitation to meet domestic needs and to earn foreign exchange from exports. Global demand for Ma...Since the late 1950’s, the Malaysian human population has nearly quadrupled, increasing pressure on natural resource exploitation to meet domestic needs and to earn foreign exchange from exports. Global demand for Malaysian palm oil in particular had steeply increased since the mid-1970s and by 2013, the commodity was the leading foreign exchange earner. To fulfill and sustain this demand, the country’s economy has steadily shifted bias towards production and associated value addition of palm oil products for export. However, as a consequence, many of Malaysia’s natural tropical forests have been converted to palm oil farming resulting in loss of approximately 10,000 km2 of forest cover over the past twenty-five years, and biodiversity has been displaced or lost. To provide a deeper insight into the interplay amongst key interrelated environmental and socio-economic variables, and a forecast of possible future balance, we used a systems dynamism modeling tool, STELLAR (structural thinking, experiential learning laboratory with animation), to simulate and project how Malaysia could achieve a medium-term sustainable balance or optimization between palm oil production and forest conservation without compromising on human social welfare. The model consisted of four main modules (environmental, economic, social development and human welfare) each with component parameters, and interconnected by input and output loops. Model calibrations, testing and preruns involved existing official 30-year time-series datasets. Subsequently, four scenarios: Environmental conservation;Economic growth under increased global palm oil demand;Economy decline under decreased palm oil demand;and Control condition with little or no change, were selected for simulated projections of future possibilities. Simulation results showed that scenarios and variable interactions that reduce environmental damage would offer the best chance for optimizing the palm oil economy while also minimizing forest loss and promoting citizen social welfare.展开更多
Potato productivity in the northeastern US has been relatively constant for over 50 years, raising questions about what factors are limiting productivity. Research was initiated in 2004 to identify key constraints to ...Potato productivity in the northeastern US has been relatively constant for over 50 years, raising questions about what factors are limiting productivity. Research was initiated in 2004 to identify key constraints to potato productivity by evaluating Status Quo (SQ), Soil Conserving (SC), and Soil Improving (SI) cropping systems under both rainfed and irrigated management, and it was found that addition of compost or irrigation substantially increased yield. In this study, we employed partial budgeting to determine cost differences and their impact on net revenue for these cropping systems. Differences in systems were primarily associated with rotation length, tillage operations, compost and application expenses, and water management practices. When compost (as composted dairy manure) was annually applied at 19 Mg haf-1 and evaluated over the entire 3-year crop rotation cycle, the compost-amended rainfed SI system was more expensive to maintain than the irrigated SC system if compost cost exceeded $3.63 Mg-1. Average marketable yields were used to calculate gross and net revenue for each system. Because average potato yield for the irrigated SQ system (28.4 Mg·ha-1) equaled that in the rainfed SI system (28.3 Mg·ha-1), we were able to compare cost of irrigation versus compost for achieving comparable yield. The compost-amended SI system under rainfed management generated more net revenue from the potato crop than the irrigated SQ system when compost costs were less than $7.42 Mg-1. When compared to the commonly used rainfed SQ system, rainfed SI achieved higher net revenue as long as compost cost was less than $22.95 Mg-1. The rainfed SI system achieved higher net revenue than the irrigated SC system when compost cost was $9.43 Mg-1or less, but generated greater net revenue than the rainfed SC system regardless of compost costs, due to substantially higher yields associated with compost amendment. This investigation demonstrates that compost is a potentially viable substitute to irrigation for potato in the northeastern US;however, such potential is highly dependent on suitable compost sources and application costs.展开更多
In order to normalize the financial account of two kinds of economic organizations,the comparative analysis is conducted on the Accounting System of Village Collective Economic Organization and Accounting System of Fa...In order to normalize the financial account of two kinds of economic organizations,the comparative analysis is conducted on the Accounting System of Village Collective Economic Organization and Accounting System of Farmers’ Cooperatives(Trial) issued by the Ministry of Finance.The comparison points out that application and accounting principles of the two kinds of accounting systems are different.The differences and similarities of the five accounting elements are analyzed including property,liabilities,rights of owners,costs and profits and losses,as well as the reasons of the differences and similarities.Results show that both of the two accounting systems reflect the principles of simplification and clarification.The village collective accounting system works in rural village committee,which acts the administrative duties,the features of concerted benefits of it is showed.While the accounting system of farmers’ cooperatives is based on the village collective accounting system and combines the norms of accounting system of enterprises,so the system represents the demands of collaboration and profit-making.展开更多
Food traceability systems are capable of overcoming or alleviating problems caused by incomplete and asymmetric information on food markets.This study conducts an empirical analysis using 308 supermarket samples from ...Food traceability systems are capable of overcoming or alleviating problems caused by incomplete and asymmetric information on food markets.This study conducts an empirical analysis using 308 supermarket samples from China's Beijing,Guangzhou,and Qingdao to determine the factors that influence supermarket behavior when operating traceability systems.The results show that operating profits(generated from food traceability systems),scale of operation,level of economic development(of a city),and government subsidies will positively affect the decision of supermarkets to use traceability systems.At the same time,government policies promoting food traceability systems should have a long-term role.展开更多
This paper presents a study to optimize the heating energy costs in a residential building with varying electricity price signals based on an Economic Model Predictive Controller (EMPC). The investigated heating syste...This paper presents a study to optimize the heating energy costs in a residential building with varying electricity price signals based on an Economic Model Predictive Controller (EMPC). The investigated heating system consists of an air source heat pump (ASHP) incorporated with a hot water tank as active Thermal Energy Storage (TES), where two optimization problems are integrated together to optimize both the ASHP electricity consumption and the building heating consumption utilizing a heat dynamic model of the building. The results show that the proposed EMPC can save the energy cost by load shifting compared with some reference cases.展开更多
To address current challenges regarding sustainable development of wastewater treatment and provide scientific support in decision procedures towards sustainable solutions, new approaches, frameworks and methodologies...To address current challenges regarding sustainable development of wastewater treatment and provide scientific support in decision procedures towards sustainable solutions, new approaches, frameworks and methodologies about different possible solutions and their potential sustainability implications are needed. One way to facilitate sustainability assessment of wastewater is Life Cycle Assessment (LCA) methodology;however, it fails to map the full scope of wastewater impacts. This paper presents a framework to evaluate the performance of Wastewater Treatment Facilities (WWTF) taking into consideration various factors for insuring environmental sustainability. A total of nine indicators, seven environmental and two economic related to four wastewater treatment facilities, were assessed. Apart from evaluating the sustainability, this study also discussed the link of life cycle approach and social aspects of wastewater. The results show that for the environmental dimension using LCA provides information on different types of environmental activities and different impact categories. LCA can thus be used to quantify and compare the multiple types of impacts caused by one type of use or emission, as well as the various resource uses or emissions that contribute to one type of impacts. For the economic dimension, there is still a need for consistent and robust indicators and methods. The empirical results suggest that the environmental sustainability framework can be used in the first phase of the decision procedure that leads to a strategic choice for sustainable resource recovery from wastewater in developing countries. This motives researchers and decision-makers to consider the whole picture, and not just individual aspects, when considering different futures scenarios.展开更多
A literature survey and focused interviews with experienced agronomists and socio-economists from south, east, and southeast Asian countries were conducted to determine physical and economic relationships of cereal yi...A literature survey and focused interviews with experienced agronomists and socio-economists from south, east, and southeast Asian countries were conducted to determine physical and economic relationships of cereal yields and N use, using partial factor productivity (PFP) and nitrogen (N) response functions, while considering the impacts of (N) and crop grain prices. The data were drawn from FAOSTAT, World Bank, and survey results from those countries. Rice has the greatest PFP-N (70 kg grain kg^-1 N), wheat a moderate (57 kg grain kg^-1 N), and maize the lowest PFP-N (52 kg grain kg^-1 N) at current application levels. At potential optimal N use rates, estimates for PFP-N were 26 kg grain kg^-1 N for maize, 25 kg for rice and 16 kg for wheat. Assuming a constant average PFP-N (30 kg grain kg^-1 N) for these cereals, it is estimated that 13 Mt N would be needed to meet a projected food demand by 2020 assuming no use of other additional inputs. Assuming a 20% increase in nitrogen use efficiency (NUE) to 36 kg grain kgl N, 10.6 Mt would be needed to meet the food demand, implying an annual growth rate in N use of 1.25%. It is concluded that economically optimal N rates are relatively insensitive to changes in prices of N and cereal grain. Key interventions to improve sustainable food security include increasing N fertilizer use, improving NUE, and reducing environmental impacts.展开更多
The Causal relation and whole-part relation are the two fundamen-tal relations in economics.In this paper,on the basis of economic prob-lems analysis in practioce,some causal relation structures of economic sys-tems a...The Causal relation and whole-part relation are the two fundamen-tal relations in economics.In this paper,on the basis of economic prob-lems analysis in practioce,some causal relation structures of economic sys-tems and fundamental rules for operations research are,at first,prop-osed.And then,a quotienting(simplifying)analysis approach of eco-nomic causal relations is presented and discussed in detail.At last,animprovement framework of system dynamics is proposed based on theviewpoint of generalized causal relations analysis.展开更多
This paper provides an overview of conventional geothermal systems and unconventional geothermal developments as a common reference is needed for discussions between energy professionals. Conventional geothermal syste...This paper provides an overview of conventional geothermal systems and unconventional geothermal developments as a common reference is needed for discussions between energy professionals. Conventional geothermal systems have the heat, permeability and fluid, requiring only drilling down to °C, normal heat flow or decaying radiogenic granite as heat sources, and used in district heating. Medium-temperature (MT) 100°C - 190°C, and high-temperature (HT) 190°C - 374°C resources are mostly at plate boundaries, with volcanic intrusive heat source, used mostly for electricity generation. Single well capacities are °C - 500°C) and a range of depths (1 m to 20 Km), but lack permeability or fluid, thus requiring stimulations for heat extraction by conduction. HVAC is 1 - 2 m deep and shallow geothermal down to 500 m in wells, both capturing °C, with °C are either advanced by geothermal developers at <7 Km depth (Enhanced Geothermal Systems (EGS), drilling below brittle-ductile transition zones and under geothermal fields), or by the Oil & Gas industry (Advanced Geothermal Systems, heat recovery from hydrocarbon wells or reservoirs, Superhot Rock Geothermal, and millimeter-wave drilling down to 20 Km). Their primary aim is electricity generation, relying on closed-loops, but EGS uses fractures for heat exchange with earthquake risks during fracking. Unconventional approaches could be everywhere, with shallow geothermal already functional. The deeper and hotter unconventional alternatives are still experimental, overcoming costs and technological challenges to become fully commercial. Meanwhile, the conventional geothermal resources remain the most proven opportunities for investments and development.展开更多
This research developed a regional economic model to estimate the ex-ante impacts of biofuel production on the economy of the southeastern United States. The analysis focuses on biofuels produced using biochemical and...This research developed a regional economic model to estimate the ex-ante impacts of biofuel production on the economy of the southeastern United States. The analysis focuses on biofuels produced using biochemical and pyrolysis technologies. The primary feedstocks considered include switchgrass (Panicum virgatum) and poplar (Populus spp.). The economic analysis modifies the Impact Analysis for Planning (IMPLAN) input-output model to determine the macroeconomic impacts of a mature industry producing biofuels using these technologies and feedstocks. Optimal facility locations are determined using a site locator model that minimizes the costs of procuring feedstock. Given a change in the land use caused by industry demand for feedstock, shocks to the farm economy are forward-linked to sectors supporting biofuel production. Key economic indicators analyzed include changes in employment and value added to the economy. System output is analyzed using a nonparametric bootstrap procedure to simulate the distributions of the impacts. The null hypothesis is that the economic impacts following the introduction of the industries are not different from baseline economic activity. Findings suggest that the net changes in employment and value added to the regional economy are positive, but modest. For example, job increases attributed to the advancement of the industries analyzed range between 0.18% and 0.95%. Total value added to the regional economy ranged between 0.15% and 0.83%.展开更多
A large number of submissions were received in response to this call for paper on the theme of COVID-19 and the financial and economic systems.Naturally,the COVID-19 pandemic has dominated much of the recent finance a...A large number of submissions were received in response to this call for paper on the theme of COVID-19 and the financial and economic systems.Naturally,the COVID-19 pandemic has dominated much of the recent finance and economics literature.This call for paper was motivated by early special issues on the COVID-19 business and economics themes such as those published by Sha and Sharma(2020)and Sharma and Sha(2020,2021).This editorial has two parts.In the first part I summarize the key outcomes from each of the papers.In the second part,I identify an agenda for future research that has emanated from this special issue papers.展开更多
基金supported by the National Natural Science Foundation of China(62103203)the General Terminal IC Interdisciplinary Science Center of Nankai University.
文摘Battery energy storage systems(BESSs)are widely used in smart grids.However,power consumed by inner impedance and the capacity degradation of each battery unit become particularly severe,which has resulted in an increase in operating costs.The general economic dispatch(ED)algorithm based on marginal cost(MC)consensus is usually a proportional(P)controller,which encounters the defects of slow convergence speed and low control accuracy.In order to solve the distributed ED problem of the isolated BESS network with excellent dynamic and steady-state performance,we attempt to design a proportional integral(PI)controller with a reset mechanism(PI+R)to asymptotically promote MC consensus and total power mismatch towards 0 in this paper.To be frank,the integral term in the PI controller is reset to 0 at an appropriate time when the proportional term undergoes a zero crossing,which accelerates convergence,improves control accuracy,and avoids overshoot.The eigenvalues of the system under a PI+R controller is well analyzed,ensuring the regularity of the system and enabling the reset mechanism.To ensure supply and demand balance within the isolated BESSs,a centralized reset mechanism is introduced,so that the controller is distributed in a flow set and centralized in a jump set.To cope with Zeno behavior and input delay,a dwell time that the system resides in a flow set is given.Based on this,the system with input delays can be reduced to a time-delay free system.Considering the capacity limitation of the battery,a modified MC scheme with PI+R controller is designed.The correctness of the designed scheme is verified through relevant simulations.
基金Supported by the Agricultural Science and Technology Innovation Funds of Jiangsu(cx(12)1001-04)~~
文摘Deep-Litter System is a high yield approach to raise swine with pollution free in a lower cost. In the research, based on the heat stress in summer caused by fermentation, three temperature-control systems were designed, including natural ventilation through transoms, forced ventilation via fans, and cooling by hyperbaric spray system. Specifically, the latter intermittent auto-pressurized spray system developed in our lab, which could spray successively via pressure from storage tubes without wetting the fermentation bed, is suitable for the promotion with the deep-litter technology in rural regions , since the power consumption is only 1 kwh per day.
基金funded by the National Water Special Program of China during 11th Five-Year Plan period(2008ZX07105-002)
文摘This study was designed to find out an optimised planting system of reducing non-point (source) pollution by analyzing the reasons and the factors of influence non-point pollution in farmland of Erhai Lake basin. The results showed that incomes, residual nitrogen in soil, and the loss of nitrogen in surface water in rice-garlic system were higher than those in rice-fava bean system. There were positive correlations between the nitrogen loss of farmland, nitrogen inputs, residual nitrogen in soil, and incomes of farmland. Economic benefits and environment benefits are both appropriate, if the area of rice-garlic system would be reduced to 53% and the area of rice-fava bean system increased to 36% of total cropping area in the investigated watershed. Adjustment of planting structure and introduction of reasonable rotation systems is considered an effective measure of controlling agricultural non-point pollution in watersheds of Erhai Lake.
基金supported by Important National Science&Technoligy Specific Projects, China (2004BA520A02)
文摘Rice-duck (RD) and rice-fish (RF) ecological systems are major complex planting and breeding models of rice paddy fields in southern China. Studying the methane (CH4) and nitrous oxide (N2O) emissions and their economic value from these two ecosystems can provide theoretical and practical basis for further development and utilization of these classical agricultural techniques. CH4 and N2O emissions from RD and RF ecological systems were measured in situ by using static chambers technique. Using global warming potentials (GWPs), we assessed the greenhouse effect of CH4 and N2O and their economic value. Results showed that the peaks of CH4 emission fluxes from RD and RF appeared at full tillering stage and at heading stage, and the average emission fluxes were significantly (P〈 0.05) lower than that from CK. N2O fluxes remained low when the field is flooded and high after draining the water. Compared with CK, the total amount of N2O emissions was significantly (P〈0.05) higher and slightly lower than those from RD and RF, respectively. In 2006 and 2007, the total greenhouse effect of CH4 and N20 from RD and RF were 4 728.3 and 4 611 kg CO2 ha^-1, 4 545 and 4 754.3 kg CO2 ha^-1, respectively. The costs of greenhouse effect were 970.89 and 946.81 RMB yuan ha^-1, and 933.25 and 976.23 RMB yuan ha^-1, respectively, which were significant lower than those from CK (5 997.6 and 5 391.5 RMB yuan ha^-1). Except for the environment cost of CH4 and N2O, the economic benefits from RD and RF were 2 210.64 and 4 881.92 RMB yuan ha^-1; 3 798.37 and 5 310.64 RMB yuan ha^-1, respectively, higher than those from CK. Therefore, RD and RF complex ecological planting and breeding models can effectively decrease and control CH4 and N2O emissions, and they are two of the effective strategies to reduce greenhouse gases from rice paddy fields and contribute in alleviating global warming. Thus, their adoption is important to the environment together with their economy benefits.
文摘Economic analysis of different diversified rotational cropping systems under Farmers' package/practices and improved package/practices was conducted in Birbhum district, West Bengal, located in the red and lateritic belt of lower Gangetic plain of eastern lndia. Diversified triple cropping systems (peanut-brinjal+brinjal, rice-potato-pumpkin, and cucumber-cabbage-basella) required higher cost for cultivation, but also produced higher rice equivalent yield, higher net return and higher return rupee1 invested in both management practices. Considering the resource-ability and risk-bearing capacity, and net return and return rupee^-1 (RPR) invested, these cropping systems can be recommended for resource-rich farmers. Rice-rapeseed-cowpea, rice-wheat-green gram and radish-tomato-amaranthus systems profitable. These cropping systems can be required less inputs for cultivation, were less risky, and economically viable and recommended for resource-poor farmers. Peanut-brinjal + brinjal-okra-chilli + chilli-cucumber-cabbage-basella system was the best among all the 3-year rotational systems in respect to RPR in both management practices. This rotational system will be suitable for resource-rich farmers. Vegetable-based rotational systems (ridge gourd-marigold-okra-black gram-pointed gourd + pointed gourd-radish-tomato-amaranthus) or rice-based rotational system (rice-wheat-green gram-rice-rapeseed-cowpea-rice-potato-pumpkin) also found to be suitable to increase the profitability and system sustainability. These cropping systems can be recommended for all groups of farmers.
文摘Extensive research work including multiple methodologies and numerous simulations have been completed in order to determine the economic effectiveness of employing CHP at commercial and residential sites. In contrast to the above, very few attempts have been made to develop methodologies to study the feasibility of CHP systems at industrial manufacturing facilities. As a result, practical opportunities for CHP at industrial sites are often not realized or even investigated. It follows that there is a need in the CHP related literature for an analysis that is explicit and yet general enough to determine the economic viability and potential for success of CHP systems at industrial manufacturing facilities. Therefore, the purpose of this paper is to clearly outline a methodology to determine the economic effectiveness of installation and operation of a CHP system at industrial facilities that have a need for space or process heating in the form of steam. The effect on the CHP system economic performance of several parameters, such as the project payback, internal rate of return, net present value, etc., are considered in the proposed methodology. The applicability and generality of the methodology is illustrated by examples including four different manufacturing facilities. The effects of the variability of factors such as annual facility operational hours during which both process heat and electricity are needed, facility average hourly thermal load, cost of utility supplied electricity, and CHP fuel type and associated fuel cost, on the outcome of the economic analysis are also examined.
基金Supported by the National Creative Research Groups Science Foundation of China (60421002) and National Basic Research Program of China (2007CB714000).
文摘In this article,an approach for economic performance assessment of model predictive control(MPC) system is presented.The method builds on steady-state economic optimization techniques and uses the linear quadratic Gaussian(LQG) benchmark other than conventional minimum variance control(MVC) to estimate the potential of reduction in variance.The LQG control is a more practical performance benchmark compared to MVC for performance assessment since it considers input variance and output variance,and it thus provides a desired basis for determining the theoretical maximum economic benefit potential arising from variability reduction.Combining the LQG benchmark directly with benefit potential of MPC control system,both the economic benefit and the optimal operation condition can be obtained by solving the economic optimization problem.The proposed algorithm is illustrated by simulated example as well as application to economic performance assessment of an industrial model predictive control system.
文摘An economic topology can have many uses to the academician, student and practitioner. Refining a topology of economic systems helps to bring together seemingly disparate characteristics and to point out potential long run trends. The progression of economic systems over time and also brief explanations of each system are given. We argue that most modem economic systems have some remnants of earlier forms, that is, most economies today are some mixture of what might be considered pure systems. Measurable characteristics to identify a particular system are developed that allows progress to or from a particular classification to be charted for individual countries.
基金supported by the National Natural Science Foundation of China(61673077)。
文摘By virtue of alternating direction method of multipliers(ADMM), Newton-Raphson method, ratio consensus approach and running sum method, two distributed iterative strategies are presented in this paper to address the economic dispatch problem(EDP) in power systems. Different from most of the existing distributed ED approaches which neglect the effects of packet drops or/and time delays, this paper takes into account both packet drops and time delays which frequently occur in communication networks. Moreover, directed and possibly unbalanced graphs are considered in our algorithms, over which many distributed approaches fail to converge. Furthermore, the proposed schemes can address the EDP with local constraints of generators and nonquadratic convex cost functions, not just quadratic ones required in some existing ED approaches. Both theoretical analyses and simulation studies are provided to demonstrate the effectiveness of the proposed schemes.
文摘Since the late 1950’s, the Malaysian human population has nearly quadrupled, increasing pressure on natural resource exploitation to meet domestic needs and to earn foreign exchange from exports. Global demand for Malaysian palm oil in particular had steeply increased since the mid-1970s and by 2013, the commodity was the leading foreign exchange earner. To fulfill and sustain this demand, the country’s economy has steadily shifted bias towards production and associated value addition of palm oil products for export. However, as a consequence, many of Malaysia’s natural tropical forests have been converted to palm oil farming resulting in loss of approximately 10,000 km2 of forest cover over the past twenty-five years, and biodiversity has been displaced or lost. To provide a deeper insight into the interplay amongst key interrelated environmental and socio-economic variables, and a forecast of possible future balance, we used a systems dynamism modeling tool, STELLAR (structural thinking, experiential learning laboratory with animation), to simulate and project how Malaysia could achieve a medium-term sustainable balance or optimization between palm oil production and forest conservation without compromising on human social welfare. The model consisted of four main modules (environmental, economic, social development and human welfare) each with component parameters, and interconnected by input and output loops. Model calibrations, testing and preruns involved existing official 30-year time-series datasets. Subsequently, four scenarios: Environmental conservation;Economic growth under increased global palm oil demand;Economy decline under decreased palm oil demand;and Control condition with little or no change, were selected for simulated projections of future possibilities. Simulation results showed that scenarios and variable interactions that reduce environmental damage would offer the best chance for optimizing the palm oil economy while also minimizing forest loss and promoting citizen social welfare.
文摘Potato productivity in the northeastern US has been relatively constant for over 50 years, raising questions about what factors are limiting productivity. Research was initiated in 2004 to identify key constraints to potato productivity by evaluating Status Quo (SQ), Soil Conserving (SC), and Soil Improving (SI) cropping systems under both rainfed and irrigated management, and it was found that addition of compost or irrigation substantially increased yield. In this study, we employed partial budgeting to determine cost differences and their impact on net revenue for these cropping systems. Differences in systems were primarily associated with rotation length, tillage operations, compost and application expenses, and water management practices. When compost (as composted dairy manure) was annually applied at 19 Mg haf-1 and evaluated over the entire 3-year crop rotation cycle, the compost-amended rainfed SI system was more expensive to maintain than the irrigated SC system if compost cost exceeded $3.63 Mg-1. Average marketable yields were used to calculate gross and net revenue for each system. Because average potato yield for the irrigated SQ system (28.4 Mg·ha-1) equaled that in the rainfed SI system (28.3 Mg·ha-1), we were able to compare cost of irrigation versus compost for achieving comparable yield. The compost-amended SI system under rainfed management generated more net revenue from the potato crop than the irrigated SQ system when compost costs were less than $7.42 Mg-1. When compared to the commonly used rainfed SQ system, rainfed SI achieved higher net revenue as long as compost cost was less than $22.95 Mg-1. The rainfed SI system achieved higher net revenue than the irrigated SC system when compost cost was $9.43 Mg-1or less, but generated greater net revenue than the rainfed SC system regardless of compost costs, due to substantially higher yields associated with compost amendment. This investigation demonstrates that compost is a potentially viable substitute to irrigation for potato in the northeastern US;however, such potential is highly dependent on suitable compost sources and application costs.
文摘In order to normalize the financial account of two kinds of economic organizations,the comparative analysis is conducted on the Accounting System of Village Collective Economic Organization and Accounting System of Farmers’ Cooperatives(Trial) issued by the Ministry of Finance.The comparison points out that application and accounting principles of the two kinds of accounting systems are different.The differences and similarities of the five accounting elements are analyzed including property,liabilities,rights of owners,costs and profits and losses,as well as the reasons of the differences and similarities.Results show that both of the two accounting systems reflect the principles of simplification and clarification.The village collective accounting system works in rural village committee,which acts the administrative duties,the features of concerted benefits of it is showed.While the accounting system of farmers’ cooperatives is based on the village collective accounting system and combines the norms of accounting system of enterprises,so the system represents the demands of collaboration and profit-making.
基金funded by The National Social Science Foundation of China "Study of the coupling supervision mechanism of China's food safety certification and traceability",The Ministry of EducationThe Humanities and Social Sciences Youth Fund of China(11YJC630027)"Double-Hundred" Research Project of Qing Dao City(2012-B-23)
文摘Food traceability systems are capable of overcoming or alleviating problems caused by incomplete and asymmetric information on food markets.This study conducts an empirical analysis using 308 supermarket samples from China's Beijing,Guangzhou,and Qingdao to determine the factors that influence supermarket behavior when operating traceability systems.The results show that operating profits(generated from food traceability systems),scale of operation,level of economic development(of a city),and government subsidies will positively affect the decision of supermarkets to use traceability systems.At the same time,government policies promoting food traceability systems should have a long-term role.
文摘This paper presents a study to optimize the heating energy costs in a residential building with varying electricity price signals based on an Economic Model Predictive Controller (EMPC). The investigated heating system consists of an air source heat pump (ASHP) incorporated with a hot water tank as active Thermal Energy Storage (TES), where two optimization problems are integrated together to optimize both the ASHP electricity consumption and the building heating consumption utilizing a heat dynamic model of the building. The results show that the proposed EMPC can save the energy cost by load shifting compared with some reference cases.
文摘To address current challenges regarding sustainable development of wastewater treatment and provide scientific support in decision procedures towards sustainable solutions, new approaches, frameworks and methodologies about different possible solutions and their potential sustainability implications are needed. One way to facilitate sustainability assessment of wastewater is Life Cycle Assessment (LCA) methodology;however, it fails to map the full scope of wastewater impacts. This paper presents a framework to evaluate the performance of Wastewater Treatment Facilities (WWTF) taking into consideration various factors for insuring environmental sustainability. A total of nine indicators, seven environmental and two economic related to four wastewater treatment facilities, were assessed. Apart from evaluating the sustainability, this study also discussed the link of life cycle approach and social aspects of wastewater. The results show that for the environmental dimension using LCA provides information on different types of environmental activities and different impact categories. LCA can thus be used to quantify and compare the multiple types of impacts caused by one type of use or emission, as well as the various resource uses or emissions that contribute to one type of impacts. For the economic dimension, there is still a need for consistent and robust indicators and methods. The empirical results suggest that the environmental sustainability framework can be used in the first phase of the decision procedure that leads to a strategic choice for sustainable resource recovery from wastewater in developing countries. This motives researchers and decision-makers to consider the whole picture, and not just individual aspects, when considering different futures scenarios.
文摘A literature survey and focused interviews with experienced agronomists and socio-economists from south, east, and southeast Asian countries were conducted to determine physical and economic relationships of cereal yields and N use, using partial factor productivity (PFP) and nitrogen (N) response functions, while considering the impacts of (N) and crop grain prices. The data were drawn from FAOSTAT, World Bank, and survey results from those countries. Rice has the greatest PFP-N (70 kg grain kg^-1 N), wheat a moderate (57 kg grain kg^-1 N), and maize the lowest PFP-N (52 kg grain kg^-1 N) at current application levels. At potential optimal N use rates, estimates for PFP-N were 26 kg grain kg^-1 N for maize, 25 kg for rice and 16 kg for wheat. Assuming a constant average PFP-N (30 kg grain kg^-1 N) for these cereals, it is estimated that 13 Mt N would be needed to meet a projected food demand by 2020 assuming no use of other additional inputs. Assuming a 20% increase in nitrogen use efficiency (NUE) to 36 kg grain kgl N, 10.6 Mt would be needed to meet the food demand, implying an annual growth rate in N use of 1.25%. It is concluded that economically optimal N rates are relatively insensitive to changes in prices of N and cereal grain. Key interventions to improve sustainable food security include increasing N fertilizer use, improving NUE, and reducing environmental impacts.
基金Supported by Gansu Porvincinl Youth Scicnce Foudation
文摘The Causal relation and whole-part relation are the two fundamen-tal relations in economics.In this paper,on the basis of economic prob-lems analysis in practioce,some causal relation structures of economic sys-tems and fundamental rules for operations research are,at first,prop-osed.And then,a quotienting(simplifying)analysis approach of eco-nomic causal relations is presented and discussed in detail.At last,animprovement framework of system dynamics is proposed based on theviewpoint of generalized causal relations analysis.
文摘This paper provides an overview of conventional geothermal systems and unconventional geothermal developments as a common reference is needed for discussions between energy professionals. Conventional geothermal systems have the heat, permeability and fluid, requiring only drilling down to °C, normal heat flow or decaying radiogenic granite as heat sources, and used in district heating. Medium-temperature (MT) 100°C - 190°C, and high-temperature (HT) 190°C - 374°C resources are mostly at plate boundaries, with volcanic intrusive heat source, used mostly for electricity generation. Single well capacities are °C - 500°C) and a range of depths (1 m to 20 Km), but lack permeability or fluid, thus requiring stimulations for heat extraction by conduction. HVAC is 1 - 2 m deep and shallow geothermal down to 500 m in wells, both capturing °C, with °C are either advanced by geothermal developers at <7 Km depth (Enhanced Geothermal Systems (EGS), drilling below brittle-ductile transition zones and under geothermal fields), or by the Oil & Gas industry (Advanced Geothermal Systems, heat recovery from hydrocarbon wells or reservoirs, Superhot Rock Geothermal, and millimeter-wave drilling down to 20 Km). Their primary aim is electricity generation, relying on closed-loops, but EGS uses fractures for heat exchange with earthquake risks during fracking. Unconventional approaches could be everywhere, with shallow geothermal already functional. The deeper and hotter unconventional alternatives are still experimental, overcoming costs and technological challenges to become fully commercial. Meanwhile, the conventional geothermal resources remain the most proven opportunities for investments and development.
文摘This research developed a regional economic model to estimate the ex-ante impacts of biofuel production on the economy of the southeastern United States. The analysis focuses on biofuels produced using biochemical and pyrolysis technologies. The primary feedstocks considered include switchgrass (Panicum virgatum) and poplar (Populus spp.). The economic analysis modifies the Impact Analysis for Planning (IMPLAN) input-output model to determine the macroeconomic impacts of a mature industry producing biofuels using these technologies and feedstocks. Optimal facility locations are determined using a site locator model that minimizes the costs of procuring feedstock. Given a change in the land use caused by industry demand for feedstock, shocks to the farm economy are forward-linked to sectors supporting biofuel production. Key economic indicators analyzed include changes in employment and value added to the economy. System output is analyzed using a nonparametric bootstrap procedure to simulate the distributions of the impacts. The null hypothesis is that the economic impacts following the introduction of the industries are not different from baseline economic activity. Findings suggest that the net changes in employment and value added to the regional economy are positive, but modest. For example, job increases attributed to the advancement of the industries analyzed range between 0.18% and 0.95%. Total value added to the regional economy ranged between 0.15% and 0.83%.
文摘A large number of submissions were received in response to this call for paper on the theme of COVID-19 and the financial and economic systems.Naturally,the COVID-19 pandemic has dominated much of the recent finance and economics literature.This call for paper was motivated by early special issues on the COVID-19 business and economics themes such as those published by Sha and Sharma(2020)and Sharma and Sha(2020,2021).This editorial has two parts.In the first part I summarize the key outcomes from each of the papers.In the second part,I identify an agenda for future research that has emanated from this special issue papers.