Procuring food enriched with diverse nutrients is pivotal for maintaining a robust immune system. However, the food system is now unprecedentedly globalized and faces challenges arising from climate change, pandemics, and political unrest. This study aims to illuminate the gap in exploring the adequacy and distribution equity of nutrition supplies in response to potential trade fluctuations and restrictions on agrifood within China's local agriculture endowments.
View Article and Find Full Text PDFThe coupled nature of the nitrogen (N) and phosphorus (P) cycling networks is of critical importance for sustainable food systems. Here we use material flow and ecological network analysis methods to map the N-P-coupled cycling network in China and evaluate its resilience. Results show a drop in resilience between 1980 and 2020, with further decreases expected by 2060 across different socio-economic pathways.
View Article and Find Full Text PDFDisruptions of key food and fertilizer exports from Russia and Ukraine have exposed many countries to challenges accessing some commodities since these countries' war began. We evaluated the short-term, external, and direct impacts of disruptions of six food commodities and three types of fertilizer supplies from Russia and Ukraine on food access for all trading partners of the two countries by applying a set of trade and socioeconomic indicators. We found that the external food supplies of 279 countries and territories were affected to varying degrees; 24 countries-especially Georgia, Armenia, Kazakhstan, Azerbaijan, and Mongolia-are extremely vulnerable because they depend almost entirely on a variety of food imports from Russia and Ukraine.
View Article and Find Full Text PDFAverting dangerous climate change requires expediting the retirement of coal-fired power plants (CFPPs). Given multiple barriers hampering this, here we forecast the future retirement ages of the world's CFPPs. We use supervised machine learning to first learn from the past, determining the factors that influenced historical retirements.
View Article and Find Full Text PDFSubstantial loss of nitrogen (N) in reactive forms (nitrogen species except for N) induced by agro-food system is a cause of the environmental degradation and harms human health. The main factors influencing the food N footprint of the Indian Subcontinent (ISC) are the nitrogen use efficiency (NUE) of crop cultivation and religious dietary cultures. In this study, we assess the food N footprint of the ISC and establish reduction scenarios toward 2050.
View Article and Find Full Text PDFThe recycling of aluminium scrap today utilizing a remelting technique downgrades the quality of the aluminium, and the final sink of this downgraded recycled aluminium is aluminium casting alloys. The predicted increase in demand for high-grade aluminium as consumers choose battery-powered electric vehicles over internal combustion engine vehicles is expected to be accompanied by a drop in the demand for low-grade recycled aluminium, which is mostly used in the production of internal combustion engines. To meet the demand for high-grade aluminium in the future, a new aluminium recycling method capable of upgrading scrap to a level similar to that of primary aluminium is required.
View Article and Find Full Text PDFThe excessive consumption of nitrogen (N) and phosphorus (P), two vital nutrients for living organisms, is associated with negative environmental and health impacts. While food production contributes to a large amount of N and P loss to the environment, very little N and P is consumed as food. Food habits are affected by multiple regulations, including the dietary restrictions and dictates of various religions.
View Article and Find Full Text PDFIn today's global economy, sustainable resource management requires a consumption perspective of resource use and insight into actual resource use through the global supply chain. The estimated global amount of used and unused extraction caused by mineral extraction of iron, copper, and nickel more than doubled from 1990 to 2013 (iron, 2.8-6.
View Article and Find Full Text PDFIn this empirically grounded perspective, we explore how, if managed correctly, mining might go beyond a straight conversion of finite natural capital to financial resources. We suggest a process where mineral extraction could act as a catalyst for more diversified growth and even serve as a basis to restore forms of 'natural capital' it had previously diminished. The case in point-small in scale but significant in consequence-is the particularly challenging instance of the small-island state of Nauru, which has a very negative history of socio-ecological impacts of phosphate mining.
View Article and Find Full Text PDFImportance of end-of-life vehicles (ELVs) as an urban mine is expected to grow, as more people in developing countries are experiencing increased standards of living, while the automobiles are increasingly made using high-quality materials to meet stricter environmental and safety requirements. While most materials in ELVs, particularly steel, have been recycled at high rates, quality issues have not been adequately addressed due to the complex use of automobile materials, leading to considerable losses of valuable alloying elements. This study highlights the maximal potential of quality-oriented recycling of ELV steel, by exploring the utilization methods of scrap, sorted by parts, to produce electric-arc-furnace-based crude alloy steel with minimal losses of alloying elements.
View Article and Find Full Text PDFEconomic growth is associated with a rapid rise in the use of natural resources within the economy, and has potential environmental impacts at local and/or global scales. In today's globalized economy, each country has indirect flows supporting its economic activities, and natural resource consumption through supply chains influences environmental impacts far removed from the place of consumption. One way to control environmental impacts associated with consumption of natural resources is to identify the consumption of natural resources and the associated environmental impacts through the global supply chain.
View Article and Find Full Text PDFThis article will outline the historical transition in the flow of phosphorus in steelmaking technology, and examine the current and future phosphorus flow in steel production and the peripheral steelmaking processes. History provides many instances of innovative changes in steelmaking processes driven by various issues associated with raw materials which emerged over time, such as supply, quality and cost issues. The major steel countries with a long history, including Sweden and Japan, have shown flexibility in their ability to adapt to the changes in the value of resources and geopolitical conditions over times, and have enacted survival resource utilization measures over many centuries, leading to improvements in their respective steelmaking processes.
View Article and Find Full Text PDFThe removability of impurities during the aluminum remelting process by oxidation was previously investigated by our research group. In the present work, alternative impurity removal with chlorination has been evaluated by thermodynamic analysis. For 43 different elements, equilibrium distribution ratios among metal, chloride flux and oxide slag phases in the aluminum remelting process were calculated by assuming the binary systems of aluminum and an impurity element.
View Article and Find Full Text PDFEven for metals, open-loop recycling is more common than closed-loop recycling due, among other factors, to the degradation of quality in the end-of-life (EoL) phase. Open-loop recycling is subject to loss of functionality of original materials, dissipation in forms that are difficult to recover, and recovered metals might need dilution with primary metals to meet quality requirements. Sustainable management of metal resources calls for the minimization of these losses.
View Article and Find Full Text PDFSteel is not elemental iron but rather a group of iron-based alloys containing many elements, especially chromium, nickel, and molybdenum. Steel recycling is expected to promote efficient resource use. However, open-loop recycling of steel could result in quality loss of nickel and molybdenum and/or material loss of chromium.
View Article and Find Full Text PDFMetals can in theory be infinitely recycled in a closed-loop without any degradation in quality. In reality, however, open-loop recycling is more typical for metal scrap recovered from end-of-life (EoL) products because mixing of different metal species results in scrap quality that no longer matches the originals. Further losses occur when meeting the quality requirement of the target product requires dilution of the secondary material by adding high purity materials.
View Article and Find Full Text PDFWaste electrical and electronic equipment (WEEE) has become an important target in managing material cycles from the viewpoint of not only waste management and control of environmental pollution but also resource conservation. This study investigated the distribution tendency of trace elements in municipal solid waste (MSW) or incinerator ash, including valuable non-ferrous metals (Ni, Co, Cr, Mn, Mo, Ti, V, W, Zr), precious group metals (PGMs) originated from WEEE (Ag, Au, Pd, Pt), and others (Al, B, Pb, Si), between Fe-rich and Cu-rich metal phases by means of simple thermodynamic calculations. Most of the typical alloying elements for steel (Co, Cr, Mo, Nb, Ni, Si, Ti, V, and W) and Rh were preferentially distributed into the Fe-rich phase.
View Article and Find Full Text PDFCoal fly ash emitted from coal-fired electric power stations generally contains environmentally regulated trace elements. In particular, boron, arsenic, and selenium have been recognized as troublesome trace elements because elutions from the fly ash contain them. In order to design an effective removal process for these trace elements, we have developed and investigated an acid-washing process.
View Article and Find Full Text PDFIn this paper, the possibility of removing impurities during magnesium recycling with pyrometallurgical techniques has been evaluated by using a thermodynamic analysis. For 25 different elements that are likely to be contained in industrial magnesium alloys, the equilibrium distribution ratios between the metal, slag and gas phases in the magnesium remelting process were calculated assuming binary systems of magnesium and an impurity element. It was found that calcium, gadolinium, lithium, ytterbium and yttrium can be removed from the remelted end-of-life (EoL) magnesium products by oxidization.
View Article and Find Full Text PDFPhosphorus is indispensable for agricultural production. Hence, the consumption of imported food indirectly implies the import of phosphorus resources. The global consumption of agricultural products depends on a small number of ore-producing countries.
View Article and Find Full Text PDFThis study presents the results of chemical thermodynamic analysis on the distribution of elements in the smelting process of metallic materials to examine the controllability of impurities in the pyrometallurgical technique. The results of the present work can give an answer against the frequently given question; "Which impurity element can be removable in metallurgical process?" or "How far can the impurity level be controlled?". The proposed method was applied to estimate the distribution of 29 elements for a copper converter and 26 elements for a steel-making process and shows the distribution tendency of elements among the gas, slag, and metal phases as well as clarifying which metals can be recovered or removed from secondary resources in metallurgical processes.
View Article and Find Full Text PDFIdentification of the flow of materials and substances associated with a product system provides useful information for Life Cycle Analysis (LCA), and contributes to extending the scope of complementarity between LCA and Materials Flow Analysis/Substances Flow Analysis (MFA/SFA), the two major tools of industrial ecology. This paper proposes a new methodology based on input-output analysis for identifying the physical input-output flow of individual materials that is associated with the production of a unit of given product, the unit physical input-output by materials (UPIOM). While the Sankey diagram has been a standard tool for the visualization of MFA/SFA, with an increase in the complexity of the flows under consideration, which will be the case when economy-wide intersectoral flows of materials are involved, the Sankey diagram may become too complex for effective visualization.
View Article and Find Full Text PDFIn previous studies on the physical chemistry of pyrometallurgical processing of aluminum scrap, only a limited number of thermodynamic parameters, such as the Gibbs free energy change of impurity reactions and the variation of activity of an impurity in molten aluminum, were taken into account. In contrast, in this study we thermodynamically evaluated the quantitative removal limit of impurities during the remelting of aluminum scrap; all relevant parameters, such as the total pressure, the activity coefficient of the target impurity, the temperature, the oxygen partial pressure, and the activity coefficient of oxidation product, were considered. For 45 elements that usually occur in aluminum products, the distribution ratios among the metal, slag, and gas phases in the aluminum remelting process were obtained.
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