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21.
Construction materials are considerable forces of global environmental impacts, but their dynamics vis‐à‐vis urban development are poorly documented, in part because their long lifespans require elusive and sometimes nonexistent decade‐long high‐resolution data. This study analyzes the construction material flow and stock trends that shaped and were shaped by the development, decline, and renewal of the Tiexi district of Shenyang, a microcosm of China's urban transformations since the early 20th century. Chronicling building‐by‐building the material flows and stock accumulations involved in the buildup of this area, we shed light on the physical resource context of its socioeconomic history. We find that 42 million tonnes of construction materials were needed to develop the Tiexi district from 1910 to 2018, and 18 million tonnes of material outflows were generated by end‐of‐life building demolition. However, over 55% of inflows and 93% of outflows occurred since 2002 during a complete redevelopment of the district. Only small portions of end‐of‐life materials could have been reused or recycled because of temporal and typological mismatches of supply and demand and technical limitations. Our analysis reveals a dramatic decrease in median building lifetimes to as low as 6 years in the early 21st century. These findings contribute to the discussion of long‐term environmental efficiency and sustainability of societal development through construction and reflect on the challenges of urban renewal processes not only in China but also in other developing and developed countries that lost (or may lose) their traditional economic base and restructure their urban forms. This article met the requirements for a Silver/Silver JIE data openness badge described at http://jie.click/badges .  相似文献   
22.
Global environmental and resource problems ask for new ways of managing the production and consumption of resources. The implementation of new paradigms, such as the circular economy, requires decision‐makers at multiple levels to make complex decisions. For this, clear analyses and modeling of scenarios are of utmost importance. Meanwhile, as the sophistication of databases and models increases so does the need for user‐friendly tools to use them. The RaMa‐Scene web platform reduces these barriers by allowing users to visualize easily diverse impacts of implementing circular‐economy interventions. This online web platform makes use of the multi‐regional environmentally extended input–output database EXIOBASE version 3 in monetary units, which has been modified to show explicit transactions of raw materials from recycling activities.  相似文献   
23.
Resource productivity enhancement stands at the center of tackling issues on environmental pollution and resource scarcity. Identifying influential socioeconomic factors should be the first step in establishing and improving resource management policy. This study compares and analyzes data from multiple countries to construct a resource productivity simulation model. The socioeconomic factors and their characteristic patterns are discussed in detail. The results demonstrate that the major factors influencing resource productivity include income level, population density, economic structure, energy structure, and raw material trade. Among these factors, the three most important are income level, population density, and economic structure. The influencing patterns can be summarized as follows: (1) Resource productivity increases with increasing income levels. (2) Countries with high population density are inclined to demonstrate high resource productivity. (3) The economic structure shows a biphase influence on resource productivity, that is, during industrialization, decreased agricultural activity and increased industrial activity lead to higher resource productivity. On the other hand, after industrialization, decreasing industrial activity and an expanding service sector become the major impetus of resource productivity enhancement. (4) Raw material export demonstrates a negative effect on resource productivity. Countries that depend heavily on raw material export show a unique resource productivity evolution pattern. For these countries, relatively high resource productivity in low income phases and relatively low resource productivity in high income phases show only small increases in resource efficiency and economic growth. Finally, insights from the study are transformed into suggestions for sustainable resource management and resource productivity enhancement.  相似文献   
24.
The growth of Korean immigrant entrepreneurship in Chicago is a product of three interacting factors: employment opportunities in the general labour market, resource mobilization, and business opportunity structures. Because of their language barrier and less transferable education and occupational skills in the American labour market, many Korean immigrants could not find white‐collar occupations for which they had been trained. Disadvantaged, but still strongly motivated for upward economic mobility in the United States, many of them became self‐employed business owners. Korean immigrants’ middle‐class backgrounds and their stable family structures and strong family ties helped them to realize their goal of business ownership. In addition, social networks based on kinship, friendship, church membership, and school ties provided prospective business owners with financial assistance, training, business advice, and information about business opportunities. The first business opportunities for Korean immigrants of Chicago opened in Korean ethnic markets and non‐ethnic minority markets almost simultaneously in the early 1970s. While the demand of Koreans for their cultural products created an economic niche for Korean‐oriented businesses, the export‐import trade linkage between South Korea and the United States has paved the way for the entrance of Korean businesses into minority areas. Because of different economic niches, the two types of Korean businesses developed independently. The interethnic succession of residence, which had occurred in the late 1960s and early 1970s also produced vacated business opportunities in Koreatown and black neighbourhoods, enabling Korean immigrants to enter these areas without great resistance from local businesses. After Korean immigrants had accumulated capital and experience in Korean ethnic markets and minority markets, they advanced into more capital‐intensive businesses like garment manufacturing. Korean immigrant professionals began to enter the Korean ethnic economy in the early 1980s when the foundation of the Korean ethnic economy was already established.  相似文献   
25.
Marcus Hunter and Zandria Robinson have provided us with an innovative methodology for analysing “maps” of African Americans’ lived political, social and cultural experiences past and present. Their powerful innovation is creating maps of the black experience based on black people’s lived experience. They argue that carefully tracing spatially blacks’ political, social and cultural patterns over time leads one to the conclusion that the shared experiences of blacks throughout the polity (and indeed throughout the Diaspora) have far more in common than not. I argue that we can better understand not only the maps that black people have created, but also chocolate cities themselves by using an analytical framework that integrates the analysis of the lived experience of black people with a structural analysis that interrogates the articulation of white supremacy, capitalism and patriarchy. This framework is related to the developing research into racial capitalism that is now being conducted globally.  相似文献   
26.
Large White male turkeys were sacrificed at 4-week intervals from 4 to 28 weeks of age to study the fatty acid distribution in lipid of breast and thigh muscles. A total of 70 turkeys were sampled for this experiment.

Fatty acid distribution varied with advancing maturity and between muscle types. The most abundant fatty acids in the tissues were those with carbon chain lengths of 15:0, 16:0, 18:0, 18:1, 18:2, 20:4 and 24:0. Thigh muscle contained significantly more linoleate (18:2) than did breast. Larger proportions of pentadecanoic (15:0), arachidonic (20:4) and lignoceric (24:0), however, appeared in breast. Indications of minor fatty acids appeared on the chromatograms, but their low concentrations made their estimation and identification difficult.  相似文献   
27.
In dairy goats, the kid rearing system can have critical importance in financial returns. Commonly used criteria for the choice of rearing system are not always clear due to the high number of factors involved. The aim of this study was to quantify all those factors to facilitate decision making. So, the effect of two different kid rearing systems, mixed rearing system (MRS) and artificial rearing system (ARS), on milk yield, milk composition and somatic cell count (SCC), milk yield loss at weaning for MRS, kid growth and costs of the different traits on the financial returns in Murciano-Granadina breed goats was studied. Twenty-four goats per group were used. In the MRS, goats reared only one kid, which had free access to goat milk 24 h a day and were weaned at week 6 of lactation, whereas kids in the ARS were separated from their mothers at kidding, colostrum and artificially reared. In both systems, dams were machine-milked once a day throughout lactation and the records took place weekly. Potential milk yield was estimated according to the oxytocin method up to week 12 of lactation, and was similar for both rearing systems, although a 12.3% drop in potential milk yield at weaning was observed for MRS. During the first 6 weeks of lactation, marketable milk was lower for dams in MRS compared to those in ARS (72.1 v. 113.0 l), but similar for the rest of the experiment (101.5 v. 99.4 l, respectively). Marketable milk composition and SCC throughout the 12 weeks of lactation were unaffected by the rearing system. Artificial rearing system entailed an increment in production cost of 22.2€ per kid compared to the rearing by MRS. A similar economic return per goat and kid was obtained from ARS and MRS in this experiment, although, due to one herd’s prolificacy of 1.8, the actual results would be 16.2€ per goat in favour of MRS. The real interest of this experiment may be the possibility of extrapolation to different flocks with diverse levels of milk production, prolificacy and prices and costs for incomes and outputs, to estimate the production system that increases returns. In conclusion, the results showed an increase in the cost of €22.2 per kid bred in the ARS, compared to the MRS, and a final return of 16.2€ per goat in favour of the mixed system.  相似文献   
28.
Renewable energy (RE) technologies are looked upon favorably to provide for future energy demands and reduce greenhouse gas (GHG) emissions. However, the installation of these technologies requires large quantities of finite material resources. We apply life cycle assessment to 100 years of electricity generation from three stand‐alone RE technologies—solar photovoltaics, run‐of‐river hydro, and wind—to evaluate environmental burden profiles against baseline electricity generation from fossil fuels. We then devised scenarios to incorporate circular economy (CE) improvements targeting hotspots in systems’ life cycle, specifically (1) improved recycling rates for raw materials and (ii) the application of eco‐design. Hydro presented the lowest environmental burdens per kilowatt‐hour of electricity generation compared with other RE technologies, owing to its higher efficiency and longer life spans for main components. Distinct results were observed in the environmental performance of each system based on the consideration of improved recycling rates and eco‐design. CE measures produced similar modest savings in already low GHG emissions burdens for each technology, while eco‐design specifically had the potential to provide significant savings in abiotic resource depletion. Further research to explore the full potential of CE measures for RE technologies will curtail the resource intensity of RE technologies required to mitigate climate change.  相似文献   
29.
The German government has adopted a law that requires sewage plants to go beyond the recovery of phosphorus from wastewater and to promote recycling. We argue that there is no physical global short‐ or mid‐term phosphorus scarcity. However, we also argue that there are legitimate reasons for policies such as those of Germany, including: precaution as a way to ensure future generations’ long‐term supply security, promotion of technologies for closed‐loop economics in a promising stage of technology development, and decrease in the current supply risk with a new resource pool.  相似文献   
30.
The objective of a circular economy (CE) is to maintain the value of products, materials, and resources in the economy by closing material loops and minimizing waste generation. In recent years, the role of public procurement has been recognized as an important, but as yet not fully exploited, opportunity by cities and municipalities in their transition toward circular societies. This study analyzed public procurement opportunities to promote CE. Different approaches and examples of circular public procurement were identified using case studies. In addition, opportunities to promote CE through sustainable and green public procurement policy were identified analyzing predefined sustainable or green public procurement criteria. The study concludes that public procurement can promote CE and related business models by setting criteria and requirements for the extension of product life spans, efficiency and/or intensity of use, and efficient cycling of biological or technical materials, as well as for the securing of clean and nonrisky cycles. Circular procurement can occur through the procurement of better‐quality products in circular terms, the procurement of new circular products, the use of business concepts that support the CE, and investments in circular ecosystems. Several sectors and product groups were identified as having potential for circular procurement, such as construction, waste, and wastewater management, transportation, food, and catering, furniture, and textiles. The study also suggests that the use of certain tools, such as performance‐based procurement, life cycle approach, and life cycle costing, as well as criteria concerning reuse and recycling of materials, could promote circular procurement. Market dialogue and cooperation between procurers and actors in the supply chains are important for the future development of circular procurement.  相似文献   
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