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Few studies reported using the convolutional neural network with transfer learning to finely classify the construction and demolition waste. This study aims to develop a highly efficient method to realize the finely sorting the construction and demolition waste, which is a key step for promoting the recycling system to realize carbon neutrality in the waste management sector. C&DWNet models, ResNet structures based on knowledge transfer and cyclical learning rate, were proposed to classify ten types of construction and demolition waste. Indexes (confusion metric, accuracy, precision, recall, F1 score, sensitivity, specificity and kappa) were adopted to evaluate the performance of various C&DWNet models. Knowledge transfer can reduce the training time and improve the performance of the C&DWNet model. The average training time is increased with the increase of the layer of C&DWNet architecture from C&DWNet-18 (946.7 s) to C&DWNet-152 (1186.6 s). The accuracy of various C&DWNet models is approximately 72–74%; the best accuracy is 73.6% in C&DWNet-152. C&DWNet-18 is more suitable for the classification of construction and demolition waste in terms of training time, accuracy, precision, and F1 score. Moreover, the t-distributed stochastic neighbor embedding can distinctly separate each type of construction and demolition waste. The environmental applications and limitations of the C&DWNet module were also discussed, which could provide a reference for the intelligent management of construction and demolition waste and promote the development of the circular economy. [ABSTRACT FROM AUTHOR]

Purpose: Evaluate environmental load of the agriculture industry by taking Chongming Island of Shanghai as a case study. Propose feasible approaches to reduce the environmental impact of agriculture industry based on the research findings. Methods: The research boundary of our study covers from raw material extraction to agriculture product (cradle to product). Two stages are identified based on life cycle thinking: agricultural material production and planting process. In the agriculture material stage, we evaluated the consumption of agricultural machinery and equipment for diesel, gasoline and electricity; then, the embodied environmental impact of these energy sources are calculated based on life cycle assessment (LCA). For the planting stage, we calculated the environmental impact caused by agriculture sowing, fertilizing, and spraying of pesticides also according to the LCA method. Results and discussion: The environmental impacts of Chongming Island in 2015 are found as ecosystem damage (2.44E+11 species year), human health (2.86E+10 DALY), and resources consumption (1.15E+09 $). The primary environmental impacts in the agricultural material production stage are revealed as marine ecological toxicity (1.01E+06), freshwater eutrophication (5.26E+05), and human toxicity (4.04E+05), of which 90% of the impacts are caused by the production of nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer. The main environmental impacts in the agricultural planting stage are freshwater ecotoxicity (1.27E+06), freshwater eutrophication (7.70E+05), and terrestrial ecotoxicity (7.70E+05), which are mainly caused by pesticide residues and loss of nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer. Conclusions: The results of the environmental impact analysis of the Chongming agricultural production of 2008–2015 showed that there was a significant decline trend in 2011 and 2012, mainly due to the significant reduction in the use of nitrogen fertilizer. The main measures for the practitioner to reduce the potential ecological damage to agricultural production are controlling the N, P, and K fertilizer application and pesticide spray volume. In addition, the ecological environment can be improved by exploring techniques and measures for efficient utilization of agricultural resources such as optimizing the amount of fertilizer and application rate. [ABSTRACT FROM AUTHOR]

Summary: It is important to have insights into the potential sustainability impacts as early as possible in the development of technology. Solar photovoltaic (PV) technologies provide significant environmental, economic, and social benefits in comparison to the conventional energy sources. Because most previous studies of multi‐crystalline silicon (Multi‐Si) PV modules discuss the environmental impacts, this study quantitatively assesses the economic and social impacts of China's multi‐crystalline silicon (mc‐Si) PV modules production stages. The economic analysis is uses life cycle cost analysis, and the social impact analysis is carried out by applying the social index evaluation method. The economic analysis results demonstrate that the main cost of mc‐Si PV modules production in China lies in raw materials and labor and the production of Multi‐Si PV cells have the highest cost among the five manufacturing processes involved in Multi‐Si PV. The result of the social impact analysis reveal that the employment contribution index, S11, is 0.72, indicating that Multi‐Si PV modules production in China has a prominent contribution to employment in comparison with other industries; the labor civilization degree, S12 (i.e., the proportion of mental labor involved in a given job), and labor income contribution index, S13, are both approximately 0.6, indicating that Multi‐Si PV modules production has a less‐significant labor level and income contribution in comparison with other industries; the production capacity contribution index, S14, is merely 0.183, indicating that production of Multi‐Si PV modules does not contribute significantly to the gross domestic product (GDP). Based on the results of these evaluations, some recommendations to improve the economic and social impact of Multi‐Si PV modules production in China are presented, including support for research on polycrystalline silicon production for the purpose of reducing the raw material cost, as well as upgrading manufacturing facilities and implementing the corresponding production training in order to promote the labor civilization degree. [ABSTRACT FROM AUTHOR]

The idea of a circular economy (CE) has become prominent in both European and Chinese policy making. Chinese and European perspectives on a CE share a common conceptual basis and exhibit many similar concerns in seeking to enhance resource efficiency. Yet they also differ, and this article explores differences in the focus of CE policy in China and Europe. We present evidence on the differing understandings of the CE concept in Chinese and European policy discourse, drawing on qualitative and quantitative analysis of policy documents, media articles, and academic publications. We show that the Chinese perspective on the CE is broad, incorporating pollution and other issues alongside waste and resource concerns, and it is framed as a response to the environmental challenges created by rapid growth and industrialization. In contrast, Europe's conception of the CE has a narrower environmental scope, focusing more narrowly on waste and resources and opportunities for business. We then examine similarities and differences in the focus of policy activity in the two regions and in the indicators used to measure progress. We show differences in the treatment of issues of scale and place and different priorities across value chains (from design to manufacture, consumption, and waste management). We suggest some reasons for the divergent policy articulation of the CE concept and suggest lessons that each region can learn from the other. [ABSTRACT FROM AUTHOR]

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Repair of mobile phones fits with the vision of a circular economy in an urban context and with the Sustainable Development Goal 11 Sustainable Cities and Communities. Drawing on the literature about firm level competitiveness and closed-loop design through repair, remanufacturing or recycling, we analyze the business ecosystem of independent mobile phone repair shops in the Netherlands, Poland and China as a glocal business activity. The analysis is based on primary data collection through a questionnaire to independent repair shops in the Netherlands (n = 130), Poland (n = 443) and China (n = 175) with response rates of 13%, 12%, 40%, respectively; and 17 interviews in the Netherlands, 40 in Poland, and 70 in China. Findings indicate that to maintain a strong position in the local market and to sustain the trust of customers, independent mobile phone repair shops offer a range of customized services based on direct contact with customers. In China, the increasing prices of spare parts and falling prices of mobile phones constitute the most important challenges, whereas in the Netherlands and Poland, the most important challenges are the competitive pressures from informal repair activities, and new repair shops. Our research also revealed that repairability strongly depends on the global manufacturers' circularity choices. [ABSTRACT FROM AUTHOR]