Supply Chain Factors Contributing to Improved Material Flow Indicators but Increased Carbon Footprint

Improvements in four material flow indicators (MFIs) have helped facilitate Japan’s transition to a sound material-cycle society. However, the economic and technological factors that have affected these MFIs have not been identified previously. Moreover, it is unclear whether the improvements in the MFIs have contributed to Japan’s progress toward carbon mitigation. In this study, we quantified the contribution of the factors in the capital-embodied supply chain to changes in the MFIs at the national and sector levels. We also examined the consistency of MFI improvements with carbon footprint reduction. Our results show that, in many sectors, structural changes in the supply chain improved two of the MFIs (resource productivity and material circularity) but increased the carbon footprint of the sector. To address this conflict, producers need to manage their supply chains based on an understanding of the nexus between material consumption and carbon emissions, paying particular attention to supply chains associated with capital formation

Hybrid Input−Output Approach to Metal Production and Its Application to the Introduction of Lead-Free Solders

The production process of metals such as copper, lead, and zinc is characterized by mutual interconnections and interdependence, as well as by the occurrence of a large number of byproducts, which include precious or rare metals, such as gold, silver, bismuth, and indium. On the basis of the framework of waste input−output (WIO), we present a hybrid IO model that takes full account of the mutual interdependence among the metal production processes and the interdependence between them and all the other production sectors of the economy as well. The combination of a comprehensive representation of the whole national economy and the introduction of process knowledge of metal production allows for a detailed analysis of different materials-use scenarios under the consideration of full supply chain effects. For illustration, a hypothetical case study of the introduction of lead-free solder involving the production of silver as a byproduct of copper and lead smelting processes was developed and implemented using Japanese data. To meet the increased demand for the recovery and recycling of silver resources from end-of-life products, the final destination of metal silver in terms of products and user categories was estimated, and the target components with the highest silver concentration were identified

Detecting Illegal Intercountry Trade of Mercury Using Discrepancies in Mirrored Trade Data

The ongoing international movement to phase out mercury, mainly led by the Minamata Convention on Mercury, raises concerns about illegal intercountry trade, including smuggling. This study aims to detect the existence of illegal intercountry mercury trade under the social mercury phase-out movement, focusing on discrepancies in each country’s trade statistics. To analyze the trends by year and country for discrepancies in intercountry mercury trade, an intraclass correlation coefficient (ICC) was applied to the mirrored exports and imports from trade statistics of each country provided by the UN Comtrade. The year-based ICC analysis identified a tendency to reduce the detection of discrepancies in the reported mirrored exports and imports for mercury at the intercountry level under the recent mercury phase-out movement. Through an ICC analysis focusing on exporting and importing countries, the validity of the ICC analysis was verified as a way to detect illegal intercountry trade of mercury. Our analyses detecting the illegal trade of related countries contribute to the effectiveness evaluation and custom capacity building required in the Minamata Convention by offering a data-driven method to enable the effective detection of illegal mercury trade

UPIOM: A New Tool of MFA and Its Application to the Flow of Iron and Steel Associated with Car Production

Identification 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. An alternative way to visually represent material flows is proposed which makes use of triangulation of the flow matrix based on degrees of fabrication. The proposed methodology is applied to the flow of pig iron and iron and steel scrap that are associated with the production of a passenger car in Japan. Its usefulness to identify a specific MFA pattern from the original IO table is demonstrated

Validation of upper thermal thresholds for outdoor sports using thermal physiology modelling

Thermal safety guidelines with upper thresholds aim to protect athletes’ health, yet evidence-based sport-specific thresholds remain unestablished. Experimenting with athletes in severely hot conditions raises ethical concerns, so we used a thermo-physiological model to validate the thresholds of guidelines for outdoor sports. First, the reproducibility of the joint system thermoregulation model (JOS-3) of core temperature has been validated for 18 sports experiments (n = 213) and 11 general exercise experiments (n = 121) using the Bland – Altman analysis. Then, core temperatures were predicted using the JOS-3 in conditions corresponding to the upper thresholds, and if the 90th–99.7th percentile core temperature value (corresponding to 0.3%–10% of the participants) exceeded 40°C, the thresholds were judged as potentially hazardous. Finally, we proposed revisions for sports with potentially hazardous thresholds. As a result, the JOS-3 could simulate core temperature increases in most experiments (27/29) for six sports and general exercises with an accuracy of 0.5°C. The current upper thresholds for marathons, triathlons, and football are potentially hazardous. Suggested revisions, based on specified percentiles, include: Football: revise from wet bulb globe temperature (WBGT) 32°C to 29–31°C or not revise. Marathon: revise from WBGT 28°C to 24–27°C. Triathlon: revise from WBGT 32.2°C to 23–26°C. If conducting sports events under the revised upper thresholds proves difficult, taking measures for a possible high incidence of heat illness becomes crucial, such as placing additional medical resources, assisting heat acclimatization and cooling strategies for participants, and rule changes such as shorter match times and increased breaks.</p

Global Mining Risk Footprint of Critical Metals Necessary for Low-Carbon Technologies: The Case of Neodymium, Cobalt, and Platinum in Japan

Meeting the 2-degree global warming target requires wide adoption of low-carbon energy technologies. Many such technologies rely on the use of precious metals, however, increasing the dependence of national economies on these resources. Among such metals, those with supply security concerns are referred to as critical metals. Using the Policy Potential Index developed by the Fraser Institute, this study developed a new footprint indicator, the mining risk footprint (MRF), to quantify the mining risk directly and indirectly affecting a national economy through its consumption of critical metals. We formulated the MRF as a product of the material footprint (MF) of the consuming country and the mining risks of the countries where the materials are mined. A case study was conducted for the 2005 Japanese economy to determine the MF and MRF for three critical metals essential for emerging energy technologies: neodymium, cobalt and platinum. The results indicate that in 2005 the MFs generated by Japanese domestic final demand, that is, the consumption-based metal output of Japan, were 1.0 × 10³ t for neodymium, 9.4 × 10³ t for cobalt, and 2.1 × 10 t for platinum. Export demand contributes most to the MF, accounting for 3.0 × 10³ t, 1.3 × 10⁵ t, and 3.1 × 10 t, respectively. The MRFs of Japanese total final demand (domestic plus export) were calculated to be 1.7 × 10 points for neodymium, 4.5 × 10^–2 points for cobalt, and 5.6 points for platinum, implying that the Japanese economy is incurring a high mining risk through its use of neodymium. This country’s MRFs are all dominated by export demand. The paper concludes by discussing the policy implications and future research directions for measuring the MFs and MRFs of critical metals. For countries poorly endowed with mineral resources, adopting low-carbon energy technologies may imply a shifting of risk from carbon resources to other natural resources, in particular critical metals, and a trade-off between increased mining risk and deployment of such technologies. Our analysis constitutes a first step toward quantifying and managing the risks associated with natural resource mining

UPIOM: A New Tool of MFA and Its Application to the Flow of Iron and Steel Associated with Car Production

Identification 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. An alternative way to visually represent material flows is proposed which makes use of triangulation of the flow matrix based on degrees of fabrication. The proposed methodology is applied to the flow of pig iron and iron and steel scrap that are associated with the production of a passenger car in Japan. Its usefulness to identify a specific MFA pattern from the original IO table is demonstrated

Thermodynamic Analysis of Contamination by Alloying Elements in Aluminum Recycling

In 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. Our results show that, except for elements such as Mg and Zn, most of the impurities occurred as troublesome tramp elements that are difficult to remove, and our results also indicate that the extent to which the process parameters such as oxygen partial pressure, temperature, and flux composition can be changed in aluminum production is quite limited compared to that for iron and copper production, owing to aluminum’s relatively low melting point and strong affinity for oxygen. Therefore, the control of impurities in the disassembly process and the quality of scrap play important roles in suppressing contamination in aluminum recycling