著者

Peter Y. Yu Manuel Cardona

出版者

Springer Verlag

巻号頁・発行日

2005

著者

Matsuda Takeshi Yano Junya Hirai Yasuhiro Sakai Shin-ichi

出版者

Springer Verlag

雑誌

The International Journal of Life Cycle Assessment (ISSN:09483349)

巻号頁・発行日

vol.17, no.6, pp.743-752, 2012-07

被引用文献数

47

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[Purpose]Source-separated collection of food waste has been reported to reduce the amount of household waste in several cities including Kyoto, Japan. Food waste can be reduced by various activities including preventing edible food loss, draining moisture, and home composting. These activities have different potentials for greenhouse gas (GHG) reduction. Therefore, we conducted a life-cycle inventory analysis of household waste management scenarios for Kyoto with a special emphasis on food waste reduction activities. [Methods]The primary functional unit of our study was “annual management of household combustible waste in Kyoto, Japan.” Although some life-cycle assessment scenarios included food waste reduction measures, all of the scenarios had an identical secondary functional unit, “annual food ingestion (mass and composition) by the residents of Kyoto, Japan.” We analyzed a typical incineration scenario (Inc) and two anaerobic digestion (dry thermophilic facilities) scenarios involving either source-separated collection (SepBio) or nonseparated collection followed by mechanical sorting (MecBio). We assumed that the biogas from anaerobic digestion was used for power generation. In addition, to evaluate the effects of waste reduction combined with separate collection, three food waste reduction cases were considered in the SepBio scenario: (1) preventing loss of edible food (PrevLoss); (2) draining moisture contents (ReducDrain); and (3) home composting (ReducHcom). In these three cases, we assumed that the household waste was reduced by 5%. [Results and discussion]The GHG emissions from the Inc, MecBio, and SepBio scenarios were 123.3, 119.5, and 118.6 Gg CO2-eq/year, respectively. Compared with the SepBio scenario without food waste reduction, the PrevLoss and ReducDrain cases reduced the GHG emissions by 17.1 and 0.5 Gg CO2-eq/year. In contrast, the ReducHcom case increased the GHG emissions by 2.1 Gg CO2-eq/year. This is because the biogas power production decreased due to the reduction in food waste, while the electricity consumption increased in response to home composting. Sensitivity analyses revealed that a reduction of only 1% of the household waste by food loss prevention has the same GHG reduction effect as a 31-point increase (from 50% to 81%) in the food waste separation rate. [Conclusions]We found that prevention of food losses enhanced by separate collection led to a significant reduction in GHG emissions. These findings will be useful in future studies designed to develop strategies for further reductions in GHG emissions.

著者

Ishii Yasuo Ota Keiichi Kuraoka Senro Tsunaki Ryosuke

出版者

Springer Verlag

雑誌

Landslides (ISSN:1612510X)

巻号頁・発行日

vol.9, no.3, pp.335-348, 2012-09

被引用文献数

49

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To monitor land deformation in detail, we ran a large-scale field test in which an artificial landslide was induced by the application of a load to a natural slope. The measured landslide displacement was reproduced numerically through the use of finite element model analysis with a two-dimensional elasto-viscoplastic model. The analysis suggested that the strength of the sliding surface decreased as the landslide mass moved. We propose a simple method for estimating safety factors. The method involves back-calculation of shear strength parameters through reproduction of observed landslide displacements and calculating the ratio of driving force to resisting force acting on the sliding surface as modeled by joint elements. This ratio, the “stability index”, shows the same trend as safety factors calculated by a two-dimensional limit equilibrium method and a shear strength reduction method that use back-calculated shear strength parameters estimated from the limit equilibrium state. The results indicate that the stability index may be applicable to the assessment of slope stability.

著者

Yano Shuichi

出版者

Springer Verlag

雑誌

Behavioral Ecology and Sociobiology (ISSN:03405443)

巻号頁・発行日

2012

被引用文献数

33

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ハダニは天敵から身を守るためによそ者同士で協力する. 京都大学プレスリリース. 2012-02-22.