Great attention has been paid to carbon bio-sequestration due to increasing concerns over global ... more Great attention has been paid to carbon bio-sequestration due to increasing concerns over global warming. Understanding the relationship between carbon bio-sequestration and its influencing factors is of great significance for formulating appropriate management measures for global warming mitigation. Since change in carbon bio-sequestration is a complex process, it is difficult to take into account all of its influencing factors, while the panel data model may provide an effective way to measure their subtle effects. In this paper, decomposition analysis is applied to further analyze these influencing factors. The results indicate that climatic, demographic and geographical variables play important roles in explaining the spatial heterogeneity of carbon bio-sequestration in China, which is consistent with previous researches. Meanwhile, the irrigation rate is found to be the most critical factor influencing carbon bio-sequestration changes, followed by climatic and economic factors. These results may provide decision makers in China with important scientific reference information for formulating regional carbon bio-sequestration management policies, which are of great significance to alleviating and adapting to global warming.
China is experiencing a high speed economic development which may exert great pressure on the env... more China is experiencing a high speed economic development which may exert great pressure on the environment and energy systems. To measure the environmental and energy performance during the economic development process, this paper selected 30 provinces, cities or autonomous regions as the decision making unit (DMU), and proposed a Green GDP index (GGI) in view of energy intensity and pollution intensity using the generalized Data Envelopment Analysis (DEA) method, and the developing trends of integrated energy and environment efficiency of DMUs from 2006 to 2010 are also demonstrated by the Malmquist index. Results show that the integrated energy and environment efficiency varies for each DMU. GGI were both 1 in Beijing and Shanghai. GGI values for the developed cities in Eastern China, such as Guangdong, Fujian, Zhejiang, Tianjin, Jiangsu, and Hainan, ranked high, while those in the Northeast and Middle China remained relatively low. Moreover, there is a positive relationship between the GGI and per capita GDP with a correlation coefficient of 0.75. Increases in GGI are also observed in the results, representing great achievements are acquired in energy conservation and emission reduction. However, the GGIs do not converge to the green frontier across the provinces.
This study presents an embodiment analysis of carbon dioxide (CO2) emission originated in fossil ... more This study presents an embodiment analysis of carbon dioxide (CO2) emission originated in fossil fuels combustion for the world economy in 2004. A global embodied CO2 intensity database associated with 112 regions and 57 sectors is obtained by applying the systems ecological input-output simulation, based on which the regional embodied CO2 inventories are compiled to investigate the emissions instigated by particular economic activities. Globally, CO2 emissions embodied in household fossil fuels combustion, in household commodity consumption, in government commodity consumption, and in investment are 3.99, 13.83, 2.07, and 5.22 Gt, respectively. As an indicator to reveal the average occupation of carbon welfare, regional per capita CO2 emission embodied in consumption varies from 0.12 t in Ethiopia to 45.16 t in Rest of North America. The severe inequality between regions is characterized by the high Gini coefficients for CO2 emissions (0.56 for direct emission and 0.58 for embodiment). And finally, the interregional carbon leakage in terms of net leakage, spill-over, and diversion is illustrated via dividing the world into three coalitions according to respective economic statuses.
The evaluation of ecosystem health in urban clusters will help establish effective management tha... more The evaluation of ecosystem health in urban clusters will help establish effective management that promotes sustainable regional development. To standardize the application of emergy synthesis and set pair analysis (EM–SPA) in ecosystem health assessment, a procedure for using EM–SPA models was established in this paper by combining the ability of emergy synthesis to reflect health status from a biophysical perspective with the ability of set pair analysis to describe extensive relationships among different variables. Based on the EM–SPA model, the relative health levels of selected urban clusters and their related ecosystem health patterns were characterized. The health states of three typical Chinese urban clusters – Jing-Jin-Tang, Yangtze River Delta, and Pearl River Delta – were investigated using the model. The results showed that the health status of the Pearl River Delta was relatively good; the health for the Yangtze River Delta was poor. As for the specific health characteristics, the Pearl River Delta and Yangtze River Delta urban clusters were relatively strong in Vigor, Resilience, and Urban ecosystem service function maintenance, while the Jing-Jin-Tang was relatively strong in organizational structure and environmental impact. Guidelines for managing these different urban clusters were put forward based on the analysis of the results of this study.
Based on the interpretation and vector processing of remote sensing images in 1985 and 2000, the ... more Based on the interpretation and vector processing of remote sensing images in 1985 and 2000, the spatial changes of wetland landscape patterns in Dadu River catchment in the last two decades were studied using spatial analysis method. Supported by Apack software, the indices of wetland landscape pattern were calculated, and the information entropy (IE) was also introduced to show the changes of wetland landscape information. Results showed that wetland landscape in this region was characteristic of patch-corridor-matrix configuration and dominantly consisted of natural wetlands. Landscape patterns changed a little with low fragment and showed concentrated distribution with partial scattered distribution during the period from 1985 to 2000. The values of patch density and convergence index kept stable, and the values of diversity, evenness indices and IE showed a slight decrease, while dominance and fractal dimension indices were increased. All types of wetland landscapes had higher adjacency probabilities with grassland landscape in 1985 and 2000, and there was extremely weak hydrological link and large spatial gap among river, glacier, reservoir and pond wetlands due to low adjacency matrix values. Since their cumulative contribution exceeded 81% through the PCA analysis, the agriculture activities would be the main driving force to the landscape changes during the past 15 years.
Energy security usually considers both the stability of energy supply and security of energy use ... more Energy security usually considers both the stability of energy supply and security of energy use and it is receiving increasing attention globally. Considering the strategic importance and sensitivity to international change of the crude oil supply, we decided to examine China’s energy security. An original network model was established based on ecological network analysis to holistically evaluate the security of the crude oil supply in China. Using this model, we found that the security of the crude oil supply in China generally increased from 2001 to 2010. The contribution of different compartments in the network to the overall energy security resembled a pyramid structure, with supply sources at the bottom, the consumption sector at the top, and the refining and transfer sectors in the middle. North and South America made the largest contribution to the security of the crude oil supply in China. We provide suggestions to improve the security of the crude oil supply in China based on our results and further scenario analysis. The original network model provides a new perspective for energy security assessment, which can be used as a baseline to develop other models and policy.
Accurate and reliable forecasting is important for the sustainable management of ecosystems. Chlo... more Accurate and reliable forecasting is important for the sustainable management of ecosystems. Chlorophyll a (Chl a) simulation and forecasting can provide early warning information and enable managers to make appropriate decisions for protecting lake ecosystems. In this study, we proposed a method for Chl a simulation in a lake that coupled the wavelet analysis and the artificial neural networks (WA–ANN). The proposed method had the advantage of data preprocessing, which reduced noise and managed nonstationary data. Fourteen variables were included in the developed and validated model, relating to hydrologic, ecological and meteorologic time series data from January 2000 to December 2009 at the Lake Baiyangdian study area, North China. The performance of the proposed WA–ANN model for monthly Chl a simulation in the lake ecosystem was compared with a multiple stepwise linear regression (MSLR) model, an autoregressive integrated moving average (ARIMA) model and a regular ANN model. The results showed that the WA-ANN model was suitable for Chl a simulation providing a more accurate performance than the MSLR, ARIMA, and ANN models. We recommend that the proposed method be widely applied to further facilitate the development and implementation of lake ecosystem management.
In this paper, Visual MODFLOW is used to simulate groundwater flow and transport within the study... more In this paper, Visual MODFLOW is used to simulate groundwater flow and transport within the study area based on a certain scenario, assessing the leakage impact of a Sewage Plant accidental pool on groundwater using NH3-N as the assessment factor. In the model constructed, soil absorption and degradation was taken into account; the adsorption process of NH3-N adopted the Langmuir equation and the degradation was simplified as a first-order dynamic reaction. The leakage process was defined as a recharge with contaminants in the case that where there are two accidents happening to the Sewage Plant within a one month interval. The result of the model indicated that the NH3-N concentration of groundwater increased sharply when the Sewage Plant was malfunctioning. The peak of NH3-N concentration under the accident pool was about 8.0 10–5 mg/L at the first accident. When the second accident happened, the NH3-N concentration increased to a maximum of about 1.1 10–4 mg/L. At a location of about 20 m from the accident pool, the concentration declined to about one sixth of the center, which demonstrated that the NH3-N concentration increase caused by leakage of the accident pool was little, and the spatial influence also was small. The paper provides a method of dealing with the transport of physically and chemically reactive substances in groundwater with Visual MODFLOW and assessing the Sewage Plant accident pool leakage impact on groundwater quantitatively.
Discovering ways in which to increase the sustainability of the metabolic processes involved in u... more Discovering ways in which to increase the sustainability of the metabolic processes involved in urbanization has become an urgent task for urban design and management in China. As cities are analogous to living organisms, the disorders of their metabolic processes can be regarded as the cause of “urban disease”. Therefore, identification of these causes through metabolic process analysis and ecological element distribution through the urban ecosystem’s compartments will be helpful. By using Beijing as an example, we have compiled monetary input– output tables from 1997, 2000, 2002, 2005, and 2007 and calculated the intensities of the embodied ecological elements to compile the corresponding implied physical input–output tables. We then divided Beijing’s economy into 32 compartments and analyzed the direct and indirect ecological intensities embodied in the flows of ecological elements through urban metabolic processes. Based on the combination of input–output tables and ecological network analysis, the description of multiple ecological elements transferred among Beijing’s industrial compartments and their distribution has been refined. This hybrid approach can provide a more scientific basis for management of urban resource flows. In addition, the data obtained from distribution characteristics of ecological elements may provide a basic data platform for exploring the metabolic mechanism of Beijing.
A so-called global city that plays an important role in regional and global economic, political a... more A so-called global city that plays an important role in regional and global economic, political and cultural development should perform well in terms of its livability. The livability level of Beijing was compared with those of three acknowledged global cities, i.e., New York City, Greater London, and Tokyo-to to clarify whether Beijing has great potential to grow into a global city. From the aspects of social development, living standard and environmental quality, the livable level integrated index (LLII) was established in this paper to evaluate the urban livability, while the linear weighted sum was applied as the assessment model. After analyzing the situations of the four cities during 2000–2009, it was indicated that the LLIIs of Beijing, New York City, Greater London, and Tokyo-to were respectively 38.76, 52.93, 50.95, and 40.65 in 2000. By comparison, the LLIIs in 2009 were 38.96, 59.23, 69.24 and 52.15, respectively. Further analysis showed that a big gap exists between the environmental quality of Beijing and those of three global cities and the performance of social development for Beijing declined in the last decade. To accelerate the transformation of Beijing to a global city, much more attention should be paid to improve the environmental quality, especially the atmospheric quality and water quality.
Industrial sector is one of the indispensable contributors in global warming. Even if the occurre... more Industrial sector is one of the indispensable contributors in global warming. Even if the occurrence of ecoindustrial parks (EIPs) seems to be a good improvement in saving ecological crises, there is still a lack of definitional clarity and in-depth researches on low-carbon industrial parks. In order to reveal the processes of carbon metabolism in a low-carbon high-tech industrial park, we selected Beijing Development Area (BDA) International Business Park in Beijing, China as case study, establishing a seven-compartment- model low-carbon metabolic network based on the methodology of Ecological Network Analysis (ENA). Integrating the Network Utility Analysis (NUA), Network Control Analysis (NCA), and system-wide indicators, we compartmentalized system sectors into ecological structure and analyzed dependence and control degree based on carbon metabolism. The results suggest that indirect flows reveal more mutuality and exploitation relation between system compartments and they are prone to positive sides for the stability of the whole system. The ecological structure develops well as an approximate pyramidal structure, and the carbon metabolism of BDA proves self-mutualistic and sustainable. Construction and waste management were found to be two active sectors impacting carbon metabolism, which was mainly regulated by internal and external environment.
This paper proposes a sustainability-oriented multiobjective optimization model for siting and si... more This paper proposes a sustainability-oriented multiobjective optimization model for siting and sizing DG plants in distribution systems. Life cycle exergy (LCE) is used as a unified indicator of the entire system’s environmental sustainability, and it is optimized as an objective function in the model. Other two objective functions include economic cost and expected power loss. Chance constraints are used to control the operation risks caused by the uncertain power loads and renewable energies. A semilinearized simulation method is proposed and combined with the Latin hypercube sampling (LHS) method to improve the efficiency of probabilistic load flow (PLF) analysis which is repeatedly performed to verify the chance constraints. A numerical study based on the modified IEEE 33-node system is performed to verify the proposed method. Numerical results show that the proposed semilinearized simulation method reduces about 93.3% of the calculation time of PLF analysis and guarantees satisfying accuracy. The results also indicate that benefits for environmental sustainability of using DG plants can be effectively reflected by the proposed model which helps the planner to make rational decision towards sustainable development of the distribution system.
Major real-estate developers of business parks around the world have made environmental responsib... more Major real-estate developers of business parks around the world have made environmental responsibility a priority in building design, construction, and operation. We review the green real-estate development movement occurring globally, and synthesize applicable concepts into a framework called the expanded business operations model (EBOM) to help companies gauge their goal of environmental stewardship. In contrast to the typical flow diagram of a typical business operations model, the EBOM indicates cycling behavior that synergistically enhances each of the four identified categories—Environment, Facilities, Business Synergism, and Green Image. The ultimate goal of these Eco-smart Corporate Communities is to positively impact the local and larger community, while increasing the economic success of property developers and their tenants. We review governmental policies that drive developers toward environ-mentally friendly techniques, outline tools and programs that assist in the implementation and evaluationof green design plans, and summarize other drivers (i.e., environmental and social issues) that encourage green building and synthesize them into an indicator system for practitioners’ reference. Using four independently operated eco-smart corporate communities as case studies, we identify the measures taken to enhance each of the four categories within the framework, and analyze the cascade of impacts. With this framework, it will be possible to set achievable goals that mark reasonable progress in corporate environmental policies.
Wetlands provide significant ecological services for urban regions in terms of water supply, wast... more Wetlands provide significant ecological services for urban regions in terms of water supply, waste water treatment, flood storage, drought resistance, etc. For wetland flows, it is crucial to understand the process of contaminant transport as it provides scientific support for applications associated with various urban services. Two indicators respectively as the critical length and duration are frequently adopted for risk assessment of incidental release of toxic or contaminant cloud. This paper presents a review on recent progresses in the analytical study of contaminant transport in wetland flows by Taylor dispersion at the phase-average scale. The method of concentration moments is introduced. Analytical procedures for determining the key quantity of Taylor dispersivity are given for typical wetlands with free water surface, respectively as the steady flow wetlands, tidal flow wetlands, and the two-layer flow wetlands. As an example of applications, critical length and duration of the contaminant cloud in the steady flow wetlands are analyzed based on the obtained Taylor dispersivity. Results show that in contrast to the temporary, localized influence of COD on water quality, the heavy metal Pb can give rise to more severe damage.
The rapid growth of population in cities places great pressure on urban ecosystem health and mana... more The rapid growth of population in cities places great pressure on urban ecosystem health and management, especially on urban water supply and disposal of wastewater. To cope with urban water degradation, indicators are needed for predicting and evaluating anthropogenic impacts on wetlands. Presented in this paper is a analytical study of the environmental dispersion in a three-layer wetland in terms of the longitudinal evolution of the lateral mean concentration. An environmental dispersion model for the mean concentration in the three-layer wetland is devised as an extension of Taylor’s classical formulation. The analytical results illustrate the effect of dimensionless parameters on the environmental dispersivity. Other related indicators for urban water quality assessment in three-layer wetlands, i.e., the critical length and duration of the contaminant cloud of typical contaminant constituents are illustrated and characterized.
Embodied water in a socio-economic system refers to the hidden water contained in products traded... more Embodied water in a socio-economic system refers to the hidden water contained in products tradedfrom one region or one sector to another and has been the center of concern for water management inrecent years. However, most models developed for water system analysis ignore cycling and indirectflows, making it difficult to explain the effects of structure on these factors among sectors. Therefore, those models fail to examine the water utilization efficiency from an integral view. In this study, weinvestigate an embodied socio-economic water system using network analysis developed originally forecological systems. In this manner, we identify structural and throughflow indicators, such as Finn Cycling Index, Indirect effects ratio, and aggradation, to show the efficiency of water utilization. The three indi-cators show different perspectives of the system’s efficiency change over time, indicating that only thecombination of these three indicators can provide a holistic portray about efficiency. Results showed thatthe structure influenced the cycling and indirect flows, and from a throughflow perspective, the systemdepends on large boundary inputs of fresh water. Furthermore, the values of Cycling Index and Indirecteffect ratio are much lower than for natural food webs, implying that the policies that led to the structuralchange and reduction of boundary fresh water inputs do not lead to positive water utilization seen innatural systems. This study provides a novel perspective and methodology for assessing the structureand efficiency of water utilization system with a whole perspective.
The key impact factors of Chinese agricultural sector water footprint change play an important ro... more The key impact factors of Chinese agricultural sector water footprint change play an important role in addressing China’s current water resource pressures. However, commonly used water footprint accounting method can only describe the situation related water resource consumption and is difficult to analyze the driving forces that shape such a situation. In this study, by taking the Chinese agricultural water footprint from 1990 to 2009 as a case, we explore the influencing factors of population, affluence, urbanization level, and diet structure on agriculture products-related water footprint change based on an extended STIRPAT model. Empirical results reveal that the all examined factors as positive driving force shave pushed forward Chinese agricultural sector water footprint increases from 549.68 Gm3in 1990 to1016.64 Gm3in 2009. Furthermore, the absolute values of normalized coefficients indicate that population has the largest positive contribution to increase the Chinese agricultural water footprint with an elastic coefficient of 0.9995, followed by affluence, diet structure, and urbanization level with elastic coefficients of 0.0874, 0.2662, and 0.2174, respectively. Finally, policies aiming at addressing current Chinese agriculture-related water resource crisis have been discussed.
In contrast to the ever-increasing focus on China's CO2 emissions, little attention has been give... more In contrast to the ever-increasing focus on China's CO2 emissions, little attention has been given to its non-CO2 greenhouse gases (GHGs). Based on the latest released official GHG emission data, this paper presents an inventory and embodiment analysis of the non-CO2 GHG emissions covering CH4, N2O, HFCs, PFCs and SF6 by the Chinese economy in 2005. The total direct non-CO2 GHG emissions from economic sectors amount to 1368.5Mt CO2- eq, of which CH4 contributes 848.4 Mt, N2O 356.8 Mt and F-GHGs 163.3 Mt. Responsible for 93.2% of the total emissions are the three sectors of Agriculture, Coal Mining and Dressing and Chemicals. Exports, urban consumption and capital formation derive the major fractions of embodied emissions for final demand. Rural and urban consumption are both non-CO2 GHG emission intensive, having the largest embodied emission intensities among all final demand categories. The impact of international trade on China's non-CO2 GHG emissions is significant. The total emissions embodied in exports are 487.0 Mt CO2-eq, equivalent to 35.6% of the total domestic emissions. Prominently, the re-exported emissions amount to 135.3 Mt CO2-eq due to the processing trade. Textile and Garments and Other Fiber Products, Leather, Furs, Down and Related Products are the top two net embodied emission export sectors. While China's non-CO2 GHG emissions are expected to increase steadily in the future, both the direct emissions from on site production and the embodied emissions induced by final consumption and international trade need to be addressed and targeted to inform effective mitigation policies.
This article models the peristaltic transport of viscous nanofluid in an asymmetric channel. The ... more This article models the peristaltic transport of viscous nanofluid in an asymmetric channel. The channel walls satisfy the convective conditions. Effects of Brownian motion and thermophoresis are taken into account. The relevant flow analysis is first modeled and then computed for the series solutions of temperature and concentration fields. Closed form expression of stream function is constructed. Plots are prepared for a parametric study reflecting the effects of Brownian motion, thermophoresis, Prandtl, Eckert and Biot numbers. It is seen that temperature is an increasing function of Brownian motion, thermophoresis, Eckert and Prandtl numbers. However temperature is found to decrease when Biot number increases. It is also observed that the nanoparticle volume fraction field has opposite results for Brownian motion and thermophoresis parameters. Heat transfer coefficient increases via Biot, Brownian, thermophoresis, Prandtl and Eckert parameters. It is also worth mentioning to point out that the trapping increases for channel width and it decreases when the flow rate is increased.
Great attention has been paid to carbon bio-sequestration due to increasing concerns over global ... more Great attention has been paid to carbon bio-sequestration due to increasing concerns over global warming. Understanding the relationship between carbon bio-sequestration and its influencing factors is of great significance for formulating appropriate management measures for global warming mitigation. Since change in carbon bio-sequestration is a complex process, it is difficult to take into account all of its influencing factors, while the panel data model may provide an effective way to measure their subtle effects. In this paper, decomposition analysis is applied to further analyze these influencing factors. The results indicate that climatic, demographic and geographical variables play important roles in explaining the spatial heterogeneity of carbon bio-sequestration in China, which is consistent with previous researches. Meanwhile, the irrigation rate is found to be the most critical factor influencing carbon bio-sequestration changes, followed by climatic and economic factors. These results may provide decision makers in China with important scientific reference information for formulating regional carbon bio-sequestration management policies, which are of great significance to alleviating and adapting to global warming.
China is experiencing a high speed economic development which may exert great pressure on the env... more China is experiencing a high speed economic development which may exert great pressure on the environment and energy systems. To measure the environmental and energy performance during the economic development process, this paper selected 30 provinces, cities or autonomous regions as the decision making unit (DMU), and proposed a Green GDP index (GGI) in view of energy intensity and pollution intensity using the generalized Data Envelopment Analysis (DEA) method, and the developing trends of integrated energy and environment efficiency of DMUs from 2006 to 2010 are also demonstrated by the Malmquist index. Results show that the integrated energy and environment efficiency varies for each DMU. GGI were both 1 in Beijing and Shanghai. GGI values for the developed cities in Eastern China, such as Guangdong, Fujian, Zhejiang, Tianjin, Jiangsu, and Hainan, ranked high, while those in the Northeast and Middle China remained relatively low. Moreover, there is a positive relationship between the GGI and per capita GDP with a correlation coefficient of 0.75. Increases in GGI are also observed in the results, representing great achievements are acquired in energy conservation and emission reduction. However, the GGIs do not converge to the green frontier across the provinces.
This study presents an embodiment analysis of carbon dioxide (CO2) emission originated in fossil ... more This study presents an embodiment analysis of carbon dioxide (CO2) emission originated in fossil fuels combustion for the world economy in 2004. A global embodied CO2 intensity database associated with 112 regions and 57 sectors is obtained by applying the systems ecological input-output simulation, based on which the regional embodied CO2 inventories are compiled to investigate the emissions instigated by particular economic activities. Globally, CO2 emissions embodied in household fossil fuels combustion, in household commodity consumption, in government commodity consumption, and in investment are 3.99, 13.83, 2.07, and 5.22 Gt, respectively. As an indicator to reveal the average occupation of carbon welfare, regional per capita CO2 emission embodied in consumption varies from 0.12 t in Ethiopia to 45.16 t in Rest of North America. The severe inequality between regions is characterized by the high Gini coefficients for CO2 emissions (0.56 for direct emission and 0.58 for embodiment). And finally, the interregional carbon leakage in terms of net leakage, spill-over, and diversion is illustrated via dividing the world into three coalitions according to respective economic statuses.
The evaluation of ecosystem health in urban clusters will help establish effective management tha... more The evaluation of ecosystem health in urban clusters will help establish effective management that promotes sustainable regional development. To standardize the application of emergy synthesis and set pair analysis (EM–SPA) in ecosystem health assessment, a procedure for using EM–SPA models was established in this paper by combining the ability of emergy synthesis to reflect health status from a biophysical perspective with the ability of set pair analysis to describe extensive relationships among different variables. Based on the EM–SPA model, the relative health levels of selected urban clusters and their related ecosystem health patterns were characterized. The health states of three typical Chinese urban clusters – Jing-Jin-Tang, Yangtze River Delta, and Pearl River Delta – were investigated using the model. The results showed that the health status of the Pearl River Delta was relatively good; the health for the Yangtze River Delta was poor. As for the specific health characteristics, the Pearl River Delta and Yangtze River Delta urban clusters were relatively strong in Vigor, Resilience, and Urban ecosystem service function maintenance, while the Jing-Jin-Tang was relatively strong in organizational structure and environmental impact. Guidelines for managing these different urban clusters were put forward based on the analysis of the results of this study.
Based on the interpretation and vector processing of remote sensing images in 1985 and 2000, the ... more Based on the interpretation and vector processing of remote sensing images in 1985 and 2000, the spatial changes of wetland landscape patterns in Dadu River catchment in the last two decades were studied using spatial analysis method. Supported by Apack software, the indices of wetland landscape pattern were calculated, and the information entropy (IE) was also introduced to show the changes of wetland landscape information. Results showed that wetland landscape in this region was characteristic of patch-corridor-matrix configuration and dominantly consisted of natural wetlands. Landscape patterns changed a little with low fragment and showed concentrated distribution with partial scattered distribution during the period from 1985 to 2000. The values of patch density and convergence index kept stable, and the values of diversity, evenness indices and IE showed a slight decrease, while dominance and fractal dimension indices were increased. All types of wetland landscapes had higher adjacency probabilities with grassland landscape in 1985 and 2000, and there was extremely weak hydrological link and large spatial gap among river, glacier, reservoir and pond wetlands due to low adjacency matrix values. Since their cumulative contribution exceeded 81% through the PCA analysis, the agriculture activities would be the main driving force to the landscape changes during the past 15 years.
Energy security usually considers both the stability of energy supply and security of energy use ... more Energy security usually considers both the stability of energy supply and security of energy use and it is receiving increasing attention globally. Considering the strategic importance and sensitivity to international change of the crude oil supply, we decided to examine China’s energy security. An original network model was established based on ecological network analysis to holistically evaluate the security of the crude oil supply in China. Using this model, we found that the security of the crude oil supply in China generally increased from 2001 to 2010. The contribution of different compartments in the network to the overall energy security resembled a pyramid structure, with supply sources at the bottom, the consumption sector at the top, and the refining and transfer sectors in the middle. North and South America made the largest contribution to the security of the crude oil supply in China. We provide suggestions to improve the security of the crude oil supply in China based on our results and further scenario analysis. The original network model provides a new perspective for energy security assessment, which can be used as a baseline to develop other models and policy.
Accurate and reliable forecasting is important for the sustainable management of ecosystems. Chlo... more Accurate and reliable forecasting is important for the sustainable management of ecosystems. Chlorophyll a (Chl a) simulation and forecasting can provide early warning information and enable managers to make appropriate decisions for protecting lake ecosystems. In this study, we proposed a method for Chl a simulation in a lake that coupled the wavelet analysis and the artificial neural networks (WA–ANN). The proposed method had the advantage of data preprocessing, which reduced noise and managed nonstationary data. Fourteen variables were included in the developed and validated model, relating to hydrologic, ecological and meteorologic time series data from January 2000 to December 2009 at the Lake Baiyangdian study area, North China. The performance of the proposed WA–ANN model for monthly Chl a simulation in the lake ecosystem was compared with a multiple stepwise linear regression (MSLR) model, an autoregressive integrated moving average (ARIMA) model and a regular ANN model. The results showed that the WA-ANN model was suitable for Chl a simulation providing a more accurate performance than the MSLR, ARIMA, and ANN models. We recommend that the proposed method be widely applied to further facilitate the development and implementation of lake ecosystem management.
In this paper, Visual MODFLOW is used to simulate groundwater flow and transport within the study... more In this paper, Visual MODFLOW is used to simulate groundwater flow and transport within the study area based on a certain scenario, assessing the leakage impact of a Sewage Plant accidental pool on groundwater using NH3-N as the assessment factor. In the model constructed, soil absorption and degradation was taken into account; the adsorption process of NH3-N adopted the Langmuir equation and the degradation was simplified as a first-order dynamic reaction. The leakage process was defined as a recharge with contaminants in the case that where there are two accidents happening to the Sewage Plant within a one month interval. The result of the model indicated that the NH3-N concentration of groundwater increased sharply when the Sewage Plant was malfunctioning. The peak of NH3-N concentration under the accident pool was about 8.0 10–5 mg/L at the first accident. When the second accident happened, the NH3-N concentration increased to a maximum of about 1.1 10–4 mg/L. At a location of about 20 m from the accident pool, the concentration declined to about one sixth of the center, which demonstrated that the NH3-N concentration increase caused by leakage of the accident pool was little, and the spatial influence also was small. The paper provides a method of dealing with the transport of physically and chemically reactive substances in groundwater with Visual MODFLOW and assessing the Sewage Plant accident pool leakage impact on groundwater quantitatively.
Discovering ways in which to increase the sustainability of the metabolic processes involved in u... more Discovering ways in which to increase the sustainability of the metabolic processes involved in urbanization has become an urgent task for urban design and management in China. As cities are analogous to living organisms, the disorders of their metabolic processes can be regarded as the cause of “urban disease”. Therefore, identification of these causes through metabolic process analysis and ecological element distribution through the urban ecosystem’s compartments will be helpful. By using Beijing as an example, we have compiled monetary input– output tables from 1997, 2000, 2002, 2005, and 2007 and calculated the intensities of the embodied ecological elements to compile the corresponding implied physical input–output tables. We then divided Beijing’s economy into 32 compartments and analyzed the direct and indirect ecological intensities embodied in the flows of ecological elements through urban metabolic processes. Based on the combination of input–output tables and ecological network analysis, the description of multiple ecological elements transferred among Beijing’s industrial compartments and their distribution has been refined. This hybrid approach can provide a more scientific basis for management of urban resource flows. In addition, the data obtained from distribution characteristics of ecological elements may provide a basic data platform for exploring the metabolic mechanism of Beijing.
A so-called global city that plays an important role in regional and global economic, political a... more A so-called global city that plays an important role in regional and global economic, political and cultural development should perform well in terms of its livability. The livability level of Beijing was compared with those of three acknowledged global cities, i.e., New York City, Greater London, and Tokyo-to to clarify whether Beijing has great potential to grow into a global city. From the aspects of social development, living standard and environmental quality, the livable level integrated index (LLII) was established in this paper to evaluate the urban livability, while the linear weighted sum was applied as the assessment model. After analyzing the situations of the four cities during 2000–2009, it was indicated that the LLIIs of Beijing, New York City, Greater London, and Tokyo-to were respectively 38.76, 52.93, 50.95, and 40.65 in 2000. By comparison, the LLIIs in 2009 were 38.96, 59.23, 69.24 and 52.15, respectively. Further analysis showed that a big gap exists between the environmental quality of Beijing and those of three global cities and the performance of social development for Beijing declined in the last decade. To accelerate the transformation of Beijing to a global city, much more attention should be paid to improve the environmental quality, especially the atmospheric quality and water quality.
Industrial sector is one of the indispensable contributors in global warming. Even if the occurre... more Industrial sector is one of the indispensable contributors in global warming. Even if the occurrence of ecoindustrial parks (EIPs) seems to be a good improvement in saving ecological crises, there is still a lack of definitional clarity and in-depth researches on low-carbon industrial parks. In order to reveal the processes of carbon metabolism in a low-carbon high-tech industrial park, we selected Beijing Development Area (BDA) International Business Park in Beijing, China as case study, establishing a seven-compartment- model low-carbon metabolic network based on the methodology of Ecological Network Analysis (ENA). Integrating the Network Utility Analysis (NUA), Network Control Analysis (NCA), and system-wide indicators, we compartmentalized system sectors into ecological structure and analyzed dependence and control degree based on carbon metabolism. The results suggest that indirect flows reveal more mutuality and exploitation relation between system compartments and they are prone to positive sides for the stability of the whole system. The ecological structure develops well as an approximate pyramidal structure, and the carbon metabolism of BDA proves self-mutualistic and sustainable. Construction and waste management were found to be two active sectors impacting carbon metabolism, which was mainly regulated by internal and external environment.
This paper proposes a sustainability-oriented multiobjective optimization model for siting and si... more This paper proposes a sustainability-oriented multiobjective optimization model for siting and sizing DG plants in distribution systems. Life cycle exergy (LCE) is used as a unified indicator of the entire system’s environmental sustainability, and it is optimized as an objective function in the model. Other two objective functions include economic cost and expected power loss. Chance constraints are used to control the operation risks caused by the uncertain power loads and renewable energies. A semilinearized simulation method is proposed and combined with the Latin hypercube sampling (LHS) method to improve the efficiency of probabilistic load flow (PLF) analysis which is repeatedly performed to verify the chance constraints. A numerical study based on the modified IEEE 33-node system is performed to verify the proposed method. Numerical results show that the proposed semilinearized simulation method reduces about 93.3% of the calculation time of PLF analysis and guarantees satisfying accuracy. The results also indicate that benefits for environmental sustainability of using DG plants can be effectively reflected by the proposed model which helps the planner to make rational decision towards sustainable development of the distribution system.
Major real-estate developers of business parks around the world have made environmental responsib... more Major real-estate developers of business parks around the world have made environmental responsibility a priority in building design, construction, and operation. We review the green real-estate development movement occurring globally, and synthesize applicable concepts into a framework called the expanded business operations model (EBOM) to help companies gauge their goal of environmental stewardship. In contrast to the typical flow diagram of a typical business operations model, the EBOM indicates cycling behavior that synergistically enhances each of the four identified categories—Environment, Facilities, Business Synergism, and Green Image. The ultimate goal of these Eco-smart Corporate Communities is to positively impact the local and larger community, while increasing the economic success of property developers and their tenants. We review governmental policies that drive developers toward environ-mentally friendly techniques, outline tools and programs that assist in the implementation and evaluationof green design plans, and summarize other drivers (i.e., environmental and social issues) that encourage green building and synthesize them into an indicator system for practitioners’ reference. Using four independently operated eco-smart corporate communities as case studies, we identify the measures taken to enhance each of the four categories within the framework, and analyze the cascade of impacts. With this framework, it will be possible to set achievable goals that mark reasonable progress in corporate environmental policies.
Wetlands provide significant ecological services for urban regions in terms of water supply, wast... more Wetlands provide significant ecological services for urban regions in terms of water supply, waste water treatment, flood storage, drought resistance, etc. For wetland flows, it is crucial to understand the process of contaminant transport as it provides scientific support for applications associated with various urban services. Two indicators respectively as the critical length and duration are frequently adopted for risk assessment of incidental release of toxic or contaminant cloud. This paper presents a review on recent progresses in the analytical study of contaminant transport in wetland flows by Taylor dispersion at the phase-average scale. The method of concentration moments is introduced. Analytical procedures for determining the key quantity of Taylor dispersivity are given for typical wetlands with free water surface, respectively as the steady flow wetlands, tidal flow wetlands, and the two-layer flow wetlands. As an example of applications, critical length and duration of the contaminant cloud in the steady flow wetlands are analyzed based on the obtained Taylor dispersivity. Results show that in contrast to the temporary, localized influence of COD on water quality, the heavy metal Pb can give rise to more severe damage.
The rapid growth of population in cities places great pressure on urban ecosystem health and mana... more The rapid growth of population in cities places great pressure on urban ecosystem health and management, especially on urban water supply and disposal of wastewater. To cope with urban water degradation, indicators are needed for predicting and evaluating anthropogenic impacts on wetlands. Presented in this paper is a analytical study of the environmental dispersion in a three-layer wetland in terms of the longitudinal evolution of the lateral mean concentration. An environmental dispersion model for the mean concentration in the three-layer wetland is devised as an extension of Taylor’s classical formulation. The analytical results illustrate the effect of dimensionless parameters on the environmental dispersivity. Other related indicators for urban water quality assessment in three-layer wetlands, i.e., the critical length and duration of the contaminant cloud of typical contaminant constituents are illustrated and characterized.
Embodied water in a socio-economic system refers to the hidden water contained in products traded... more Embodied water in a socio-economic system refers to the hidden water contained in products tradedfrom one region or one sector to another and has been the center of concern for water management inrecent years. However, most models developed for water system analysis ignore cycling and indirectflows, making it difficult to explain the effects of structure on these factors among sectors. Therefore, those models fail to examine the water utilization efficiency from an integral view. In this study, weinvestigate an embodied socio-economic water system using network analysis developed originally forecological systems. In this manner, we identify structural and throughflow indicators, such as Finn Cycling Index, Indirect effects ratio, and aggradation, to show the efficiency of water utilization. The three indi-cators show different perspectives of the system’s efficiency change over time, indicating that only thecombination of these three indicators can provide a holistic portray about efficiency. Results showed thatthe structure influenced the cycling and indirect flows, and from a throughflow perspective, the systemdepends on large boundary inputs of fresh water. Furthermore, the values of Cycling Index and Indirecteffect ratio are much lower than for natural food webs, implying that the policies that led to the structuralchange and reduction of boundary fresh water inputs do not lead to positive water utilization seen innatural systems. This study provides a novel perspective and methodology for assessing the structureand efficiency of water utilization system with a whole perspective.
The key impact factors of Chinese agricultural sector water footprint change play an important ro... more The key impact factors of Chinese agricultural sector water footprint change play an important role in addressing China’s current water resource pressures. However, commonly used water footprint accounting method can only describe the situation related water resource consumption and is difficult to analyze the driving forces that shape such a situation. In this study, by taking the Chinese agricultural water footprint from 1990 to 2009 as a case, we explore the influencing factors of population, affluence, urbanization level, and diet structure on agriculture products-related water footprint change based on an extended STIRPAT model. Empirical results reveal that the all examined factors as positive driving force shave pushed forward Chinese agricultural sector water footprint increases from 549.68 Gm3in 1990 to1016.64 Gm3in 2009. Furthermore, the absolute values of normalized coefficients indicate that population has the largest positive contribution to increase the Chinese agricultural water footprint with an elastic coefficient of 0.9995, followed by affluence, diet structure, and urbanization level with elastic coefficients of 0.0874, 0.2662, and 0.2174, respectively. Finally, policies aiming at addressing current Chinese agriculture-related water resource crisis have been discussed.
In contrast to the ever-increasing focus on China's CO2 emissions, little attention has been give... more In contrast to the ever-increasing focus on China's CO2 emissions, little attention has been given to its non-CO2 greenhouse gases (GHGs). Based on the latest released official GHG emission data, this paper presents an inventory and embodiment analysis of the non-CO2 GHG emissions covering CH4, N2O, HFCs, PFCs and SF6 by the Chinese economy in 2005. The total direct non-CO2 GHG emissions from economic sectors amount to 1368.5Mt CO2- eq, of which CH4 contributes 848.4 Mt, N2O 356.8 Mt and F-GHGs 163.3 Mt. Responsible for 93.2% of the total emissions are the three sectors of Agriculture, Coal Mining and Dressing and Chemicals. Exports, urban consumption and capital formation derive the major fractions of embodied emissions for final demand. Rural and urban consumption are both non-CO2 GHG emission intensive, having the largest embodied emission intensities among all final demand categories. The impact of international trade on China's non-CO2 GHG emissions is significant. The total emissions embodied in exports are 487.0 Mt CO2-eq, equivalent to 35.6% of the total domestic emissions. Prominently, the re-exported emissions amount to 135.3 Mt CO2-eq due to the processing trade. Textile and Garments and Other Fiber Products, Leather, Furs, Down and Related Products are the top two net embodied emission export sectors. While China's non-CO2 GHG emissions are expected to increase steadily in the future, both the direct emissions from on site production and the embodied emissions induced by final consumption and international trade need to be addressed and targeted to inform effective mitigation policies.
This article models the peristaltic transport of viscous nanofluid in an asymmetric channel. The ... more This article models the peristaltic transport of viscous nanofluid in an asymmetric channel. The channel walls satisfy the convective conditions. Effects of Brownian motion and thermophoresis are taken into account. The relevant flow analysis is first modeled and then computed for the series solutions of temperature and concentration fields. Closed form expression of stream function is constructed. Plots are prepared for a parametric study reflecting the effects of Brownian motion, thermophoresis, Prandtl, Eckert and Biot numbers. It is seen that temperature is an increasing function of Brownian motion, thermophoresis, Eckert and Prandtl numbers. However temperature is found to decrease when Biot number increases. It is also observed that the nanoparticle volume fraction field has opposite results for Brownian motion and thermophoresis parameters. Heat transfer coefficient increases via Biot, Brownian, thermophoresis, Prandtl and Eckert parameters. It is also worth mentioning to point out that the trapping increases for channel width and it decreases when the flow rate is increased.
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