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Exploring the sustainability of urban ecosystem is becoming a key area in global sustainable development. Urban metabolism is an effective analysis tool for the study of urban ecosystem. In this regard, how to evaluate the level of urban sustainable development and identify the key factors that affect urban metabolism is critical. Many studies on urban metabolism have been explored during the past half century, but few concerns about the key factors that affect urban metabolism. Therefore, this paper fills such a gap by combining emergy and Logarithmic Mean Divisia Index (LMDI) methods in order to analyze the sustainable development level and identify the driving forces of emergy utilization, respectively. A typical industrial city, Shenyang in northeast China, was chosen as a case study city in this paper. Results show that renewable resource utilization in Shenyang was very limited from 2000 to 2010, while nonrenewable resources and the imported resources increased rapidly. During this period, total emergy utilization of Shenyang increased from 8.52 × 10 22 sej to 21.53 × 10 22 sej, and emergy density increased with annual increasing rate of 10.34%, demonstrating a fast development of the economy and high level of resident's consumption. LMDI method was employed to analyze the driving forces of emergy consumption from the aspects of scale, structure and intensity. Results show that the rapid increase of emergy utilization in Shenyang was mainly caused by the expansion of economic scale, while emergy intensity greatly contributed to offset total consumption, and industry structure played a marginal role, with a minor value for its growth. Based upon these results, several policy recommendations were raised, including the use of more renewable and clean energy sources, a regenerative and preventative eco-industrial development approach, and capacity-building efforts, so that the overall environment pressure on urban development can be reduced. [ABSTRACT FROM AUTHOR]

The stamping industry is critical in the automotive and aerospace industries, and the environmental impacts and sustainability of stamping systems have attracted considerable attention. To analyze the environmental impact and sustainability of stamping systems quantitatively, this paper presents an emergy-based evaluation method considering all the associated environmental impact factors of a pressing workshop including material and energy consumption, waste flows, time and mass losses, and processing costs. On the basis of analyzing the stamping processes and sustainability, this method comprises data collection, emergy based sustainability evaluation model and the development of sustainable evaluation indexes and systems. Based on the proposed method, the environmental impact of an industrial vehicle stamping workshop was evaluated. The results show that the net emergy yield ratio of the stamping system was greater than 2, and the waste emergy output ratio was very low, indicating that the system had high productivity levels, high yields, and low pollution discharge rates. However, its sustainability index was less than one owing to its high energy and material consumption during the production processes. To reduce the environmental impact of this stamping system and improve its sustainability, we investigated the potential improvements that could be achieved in energy consumption, productivity, and environmental impact by implementing energy-saving scheduling in the stamping workshop. The results show that the corresponding net emergy yield ratio and sustainability index of the system were both improved. The proposed emergy-based method could be used to quantitatively evaluate the environmental impacts and sustainability of stamping systems and facilitate efforts to reduce the environmental impacts of pressing workshops while improving their productivity and economic profitability. [ABSTRACT FROM AUTHOR]