著者

醍醐 市朗 五十嵐 佑馬 松野 泰也 足立 芳寛

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.93, no.1, pp.66-70, 2007-01-01

被引用文献数

2 17

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During the last two decades, the total material input in Japan has been about 2 billion tons, and approximately 50%, i.e., about 1 billion tons has accumulated as the net addition to stock in the form of buildings, social infrastructure, and various kinds of products. The amount of the net addition to stock is calculated annually from the differential between the input and the output. Therefore, the contents of the accumulated stock are unknown. It is said that these unknown contents include material that has already been discarded as invisible waste. In this study, dynamic material flow analysis was conducted to quantify the amount of stock that is not associated with social activities and cannot possibly be collected as scrap in the future. First, we defined some terms: in-use stock, hibernating stock, and overall stock. Hibernating stock comprises the steel used for the constructional material of land fill site, the steel dissipated by corrosion and erosion, etc. Furthermore, we defined the system boundary to account for the steel stock and constructed equations to calculate the three types of stock. To calculate the amount of in-use stock, a dynamic model-the population balance model-was adopted. The amounts of in-use stock and hibernating stock in Japan from 1980 to 2000 were calculated. The result shows that 0.96 billion tons of the in-use stock is included in the 1.22 billion tons of overall stock in the year 2000.

著者

森口 祐一 工藤 祐揮 松八重 一代 福島 康裕 醍醐 市朗 中島 謙一 栗島 英明 菊池 康紀 中谷 隼 田原 聖隆 井原 智彦 兼松 祐一郎

出版者

東京大学

雑誌

基盤研究(A)

巻号頁・発行日

2015-04-01

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本研究課題では,国内産業および輸入原料を含む国産製品のサプライチェーンを対象として,それが産み出す社会価値と,地域レベルおよび地球レベルで発生する環境・資源ストレスの統合的ホットスポット分析の枠組みを確立することを目的とした。輸入資源の国際サプライチェーン分析,地域における再生可能エネルギー供給システム,産業廃棄物の地域間分析,サプライチェーンの地震リスクといった数多くの事例分析を実施し,それぞれ潜在的なストレス・リスク要因のホットスポットを特定した。さらに,分析方法のアルゴリズムおよび原単位のデータベースをソフトウェアに実装することで,ホットスポット分析の枠組みの汎用化を目指した。

著者

醍醐 市朗 後藤 芳一

出版者

一般社団法人 日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.100, no.6, pp.756-760, 2014 (Released:2014-05-31)

参考文献数

14

被引用文献数

1 7

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In this study, a random sample of 107 steel bars from Japan and 26 steel bars from China were studied. Each specimen’s elemental composition of tramp elements, such as Cu, Cr, Ni, and Sn, was analyzed. By using the compositions of specific tramp elements, 99 of the 107 samples and 16 of the 26 samples were recognized as electric arc furnace steel. The distributions of the tramp element composition were obtained for the Japanese steel bars and represent a larger number of samples than previous studies. Those for the Chinese samples are the first published data. The compositions of Cu, Cr, Ni, and Sn in the Japanese bars are statistically significantly higher than those in the Chinese bars. Owing to the large gap between the Cu contents of the Japanese and Chinese samples, and the statistically significantly differences between the ratios of Cu to both Ni and Cr in the Japanese and Chinese samples, it is highly likely that copper-based materials are separated from steel scrap at a higher rate in China. The relationship between the Cu and Cr compositions suggested that the mixing of copper-based materials and special steels, which contribute to Cr contamination, differs between Japan and China. The distributions of the Cr composition for each country had larger standard deviations than the distributions of other elements. The ratio of the Cr and Ni compositions in the Chinese samples is less than 2.25, resulting in 18% Cr and 8% Ni in stainless steel. It was found that Ni from materials other than stainless steel was likely to have been included.

著者

平戸 崇博 醍醐 市朗 松野 泰也 足立 芳寛

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.95, no.1, pp.96-101, 2009-01-01

被引用文献数

2 16

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Recently, prices of natural resources have rapidly risen, so recovery of materials from the end-of-life products as secondary resources is of great interest. However, it is generally a challenging task to estimate the in-use stock of materials, especially in developing countries, because of lack of data. In this paper, two approaches, a top-down approach and a bottom-up approach, were adopted for estimating the in-use steel stock in end uses. A top-down approach uses time-series data of consumption and trade of materials and product lifetime data, whereas a bot-tom-up approach uses the numbers of units of a specified product in a designated area and its material intensities. In this paper, the steel stock in Japan divided into six end uses was estimated by the top-down approach. The steel in-use stock in Japan was estimated as approximately 1,000Tg in 2005. Steel stock in automobiles in 2005 was estimated as 105Tg by the bottom-up approach and compared with that estimated as 125Tg by the top-down approach. In addition, applying the bottom-up approach, steel stock used in automobiles in U.S. was estimated and compared with that obtained by the previous research using a top-down approach. Steel stock used in automobiles in 2000 in U.S. was estimated as 480-870Tg by the top-down approach and 754-767Tg by the bottom-up approach. Both approaches have some uncertainties in the parameters used in the estimation. Therefore, complementary use of the two approaches is helpful to estimate in-use stock of materials.