Journal of Life Cycle Assessment, Japan
Online ISSN : 1881-0519
Print ISSN : 1880-2761
ISSN-L : 1880-2761
Volume 5 , Issue 1
Showing 1-25 articles out of 25 articles from the selected issue
Contents
  • 2009 Volume 5 Issue 1 Pages Toc_1-Toc_4
    Published: 2009
    Released: December 15, 2019
    JOURNALS FREE ACCESS
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Foreword
Review Article
  • Hidefumi IMURA
    2009 Volume 5 Issue 1 Pages 2-11
    Published: 2009
    Released: December 15, 2019
    JOURNALS FREE ACCESS

    Objective. LCAs started to measure the “cradle to grave” environmental impact of wider range of human activities and economic systems including different processes and technology systems. Since the 1990s, the LCA standard (ISO 14040) has been developed with a view to establishing a basic method applicable to industrial products and consumer goods intended for the mass market. On the other hand, the concept and method of LCA have been extended to apply to non-consumer goods such as buildings and civil infrastructures which are public or semi-public goods. In the late 1990s, Imura and others developed “Infrastructure LCA”, targeting urban infrastructures such as subways, roads, harbors, waste water treatment plants, and municipal solid waste collection and treatment system. They conducted case studies to quantify the energy and raw materials consumption and different types of emissions pertinent to the construction, operation and maintenance of urban infrastructures, but the integrated analysis of environmental implications and social and economic functions of infrastructures was not fully developed. This paper tries to explore a framework of applying LCA to social systems consisting of technological systems to support human life and economic activities in cities.
    Results and Discussion. In conducting LCA, the term “social system” refers a social organism consisting of a set of “technology systems” providing various social and public services, which are put in motion by material and energy metabolism of the society. On the other hand, in sociology, “social system” is synonymous to “social structure” which refers to entities or groups in definite relation to each other, and it also means social institutions and norms embedded in the society. The technology systems and embedded institutions altogether shape the behavior of actors within the social systems. Based on these considerations, this paper focuses on the human activities in cities and classifies the LCA of social systems to three layers. The first is the holistic analysis of cities which comprises a number of “technology systems” such as transportation, telecommunication and information, water, electricity supply, waste collection and disposal, and other systems, and we call it “LCA of cities”. The second is the LCA of different technology systems as mentioned above. The last is the LCA of specific infrastructures such as roads and railways which comprises transportation system. Here, infrastructures and certain products, e.g., roads and cars are closely linked and their LCAs should be conducted jointly, and we call this “extended infrastructure LCA”.
    Conclusions. Modern cities are functioning thanks to a set of technology systems comprising a variety of social infrastructures and products. Innovation in products such as cars or mobile phones is coupled with transformations in technology systems such as transportation or communication and information systems, and they bring about major or even drastic changes in society together with changes in material and energy metabolism. Focusing on cities, this paper presents a general framework of LCA applicable to social systems. It discusses three stratifications of LCAs with different purposes and approaches. The next important step is to conduct more case studies to promote the application of LCA to social systems.

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  • Hirokazu KATO, Naoki SHIBAHARA
    2009 Volume 5 Issue 1 Pages 12-19
    Published: 2009
    Released: December 15, 2019
    JOURNALS FREE ACCESS

    Objective. “ELCEL (Extended Life Cycle Environmental Load)” is a concept for evaluating changes in environmental impacts over the entire range of an infrastructure provision project’s influences. The application of the ELCEL concept to the environmental evaluation of a project which changes a social system is examined.
    Results and Discussion. A social system consists of various activities in a society, as well as the hard or soft infrastructure that supports them. The life cycle negative environmental impact of infrastructure has been researched using various approaches. Conservative infrastructure LCA traces unique development paths that differ from LCA in the industrial product field because infrastructure provision can change the entire social system. Not only the evaluation considering spillover effect to the whole society but also the consideration of the interrelationship among components in a social system is important. This approach is called “Social/Dynamic LCA” which means that system boundary needs to be extended, and its extension means introduction of the ELCEL concept. In addition, the main problems for establishing LCA for social system by the ELCEL concept are described. They can be summarized as follows: a) setting of spatial boundary; b) setting of temporary boundary; c) management of the trade-off between uncertainty and boundary; and d) a framework of the project evaluation method including LCA.
    Conclusions. The key point to solve these problems by applying LCA to social systems is the Social/Dynamic LCA approach. We have tried to introduce the ELCEL concept to establish a methodology for evaluating social systems based on life cycle thinking, but several problems still remain. Authors will continue the work to establish the ELCEL concept.

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Commentary and Discussion
  • Yutaka GENCHI
    2009 Volume 5 Issue 1 Pages 20-25
    Published: 2009
    Released: December 15, 2019
    JOURNALS FREE ACCESS

    The outline of a project on the application of LCA to local measures in Chiba and Iwate prefectures were summarized. We described seven remaining tasks on the project from the results of joint research program with these two prefectures. Seven remaining tasks are related to inventory data construction, impact assessment, consideration of local characteristics, comparison of alternatives, treatment of complex systems, inter-relationship of environmental impacts among regions and assessment of time schedule. Demand of LCA application to local measures will rise in the near future, because local governments have paid attention to construct effective environmental measures, such as decreasing the greenhouse gases emission, promoting carbon labeling and the environmental model city project. Life cycle thinking approach related to local measures should consider these seven tasks. We will research and develop an LCA methodology for realistically supporting measures taken by local governments and regional activities.

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  • Hideaki KURISHIMA, Haruki SETOYAMA, Yutaka GENCHI
    2009 Volume 5 Issue 1 Pages 26-32
    Published: 2009
    Released: December 15, 2019
    JOURNALS FREE ACCESS

    Objective. The features of suburban shopping mall are a low-rise and low cost building, road side location and a spacious flat parking lot, and these cause an energy-inefficiency and air pollution from private cars of visitors. It is effective for such problems that the Life Cycle Assessment (LCA) for suburban shopping mall. On the other hand, it has some technical problems. The purpose of this paper is to sort out technical problems and to examine case study to overcome these problems.
    Results and Discussion. First, LCA cannot consider the change in a different type and the scale of business, because these functional units are not corresponding. We invoked the concept of the “Eco-efficiency” to overcome this problem. Second, it is necessary to expand the system boundary to examine the ripple effect and the baseline of development. We examine the ripple effect of shopping mall location using trade area analysis. Moreover, we evaluate the environmental load of region as a baseline and prove the effect of regional partnership.
    Conclusions. The result is as follows. It shows the possibility that total environmental impact of private car decreases by facilities location. Moreover, it quantitatively evaluates the increment by the business and the environmental improvement by regional partnership.

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General Articles
  • Ryoko MORIMOTO, Naoki SHIBAHARA, Hirokazu KATO
    2009 Volume 5 Issue 1 Pages 33-39
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Objective. Road traffic contributes significantly to carbon dioxide (CO2) emissions. Road improvement projects are one of the effective measures to reduce CO2 emissions. In this study, a methodology based on the Life Cycle Assessment (LCA) approach is developed for evaluating environmental impacts of road improvement projects.
    Results and Discussion. A framework for evaluating environmental loads from road transport system including road infrastructure and vehicle traveling is proposed. The framework also enables us to analyze changes in driving conditions that are influenced by road improvement. Further, it evaluates the impacts due to induced traffic and change in traffic speed. The method is applied to a road improvement projects involving removal of a railway crossing by constructing an elevated track. A project undertaken in this study can reduce System Life Cycle CO2 (SyLC-CO2) because it improves driving conditions by reducing stops and congestion due to railroad crossing. However, sensitivity analysis shows the following important findings: 1) SyLC-CO2 increases if traffic volume increases by more than 1.28 times after the project; 2) For a crossing where the traffic volume is less than 3,000 vehicles, such a project is unsuitable because the SyLC-CO2 increases after the project; 3) Large traffic volume is not required to reduce SyLC-CO2 if the crossing is closed long times.
    Conclusions. The results of a sensitivity analysis carried out under different traffic conditions indicate that there is an overall decrease in CO2 emissions because, despite improvements in driving conditions, the environmental load contributed by road traffic is greater than the total load contributed by infrastructure construction and induced traffic.
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  • Naoki SHIBAHARA, Hirokazu KATO, Yoshitsugu HAYASHI
    2009 Volume 5 Issue 1 Pages 40-46
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Objective. The focus of carbon dioxide (CO2) emissions reduction policies for the inter-regional passenger transport system depends on two factors: 1) the aviation sector is the slowest to eliminate use of carbon fuels; and 2) aviation is expected to contribute more to greenhouse gas emissions than other transport modes. Therefore, the purpose of this study is to explore the possible changes in each indicator of Life Cycle CO2 (LC-CO2) per passenger-km and eco-efficiency considering travel speed as a result of a shift from aviation to the high speed railway system (Shinkansen). CO2 emissions both for aviation and Shinkansen were estimated by applying the Life Cycle Assessment (LCA) method and taking into account same important parameters such as passenger demand.
    Results and Discussion. CO2 exhausted from aviation and Shinkansen during normal operation and the additional LC-CO2 from new infrastructure provision were compared. The first analyzed the sensitivity with regard to the number of passengers for a 500km long corridor. The results indicate the following: 1) CO2 per passenger-km generated from aviation hardly vary with the number of passengers; 2) LC-CO2 per passenger-km for Shinkansen is inversely proportional to the number of passengers; 3) LC-CO2 per passenger-km for Shinkansen is lower than that for aviation for the passenger volume of approximately 1,200 or more passengers per day; and 4) for eco-efficiency, the break-even point is more than around 2,000 passengers per day. The second considers the distance and travel demand for both aviation and Shinkansen. A possible shift from the current demand for aviation to Shinkansen was compared for each inter-prefectural Origin-Destination (OD) pair. Shinkansen was found to be superior for OD pairs with higher demand and shorter distances.
    Conclusions. This paper proposed a methodology for identifying an inter-regional transport system with lower CO2 emissions. An application to the inter-prefectural ODs for existing airlines in Japan shows the conditions that provide an advantage of lower CO2 emissions for aviation or Shinkansen.
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  • Ryoko MORIMOTO, Hirokazu KATO, Naoki SHIBAHARA, Hiroshi KINPARA
    2009 Volume 5 Issue 1 Pages 47-53
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Objective. The aim of this study is to evaluate the environmental load of the distribution stage which is as important as the production stage. This study constructs an LCA (Life Cycle Assessment) framework for production, which evaluates the environmental load influenced by different distribution and sales form. This framework includes the delivery, cargo work, safekeeping, sale and the shopping trip of the consumer as part of distribution stage. Vending machine, large-scale retail store and convenience store are compared as forms of sales. Details of the lifecycle environmental load of the distribution stage are analyzed, and effective measures to reduce the environmental load (CO2) are examined.
    Results and Discussion. This study analyzes the lifecycle environmental load of cooling a soft drink in a can and the difference among the distribution and sales forms. Percentage in the LC-CO2 is 47% with large-scale retail store, 56% with convenience store, 57% with vending machine. It is found that the distribution stage has a great influence on LC-CO2. Vending machine exhausts most LC-CO2, mainly because of refrigeration, and for large-scale retail store, shopping trip make a large share. The analyzes suggests four major measures for reducing LC-CO2 : 1) It is effective to shorten the stock time of the vending machine; 2) LC-CO2 in buying a drink from a vending machine and consuming it immediately is less than LC-CO2 in buying it from a large-scale retail store and putting it in a refrigerator for a long time; 3) A trade-off between the stock time in refrigerators and frequent delivery of small quantities indicates the optimal delivery interval of six days; 4) CO2 emissions can be reduced by 15% if consumer make shopping trip by bus, scooter or bicycle.
    Conclusions. The share of distribution and sales stages is dominant. To propose the LC-CO2 reduction measure requires an evaluation of the difference among the forms of distribution.
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  • Tomohiro TABATA, Tomohiko IHARA, Hiroshi NAKAZAWA, Yutaka GENCHI
    2009 Volume 5 Issue 1 Pages 54-67
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Background, Aim and Scope. Municipal Solid Waste (MSW) management system has an important role to reduce final disposal of MSW. Recently prevention of global warming in MSW transportation and treatment processes is also coming into important. Decision makers in local region should design the MSW management system that solves above issues, and is desirable for the region in cost constraint. But there are few studies taking into account regional MSW discharge and waste treatment properties and their perspective. In this study, we proposed a methodology to design environmentally and economically desirable MSW management systems in local region by applying Life Cycle Assessment (LCA) and cost analysis.
    Materials and Methods. The central region of Iwate Prefecture was chosen as a case study. Firstly, we surveyed material and energy inputs/outputs in MSW transportation and treatment processes in the case study area. Then, Life Cycle Inventory (LCI) data of each process was calculated. Secondarily, scenarios involving several MSW management systems considering patterns of MSW treatment technologies and/or MSW segregation were designed.
    Results and Discussion. As a scenario analysis, Greenhouse Gas (GHG) emissions, SOx/NOx emissions, final disposal and the cost was calculated when each scenario would be for the period from FY2005 to FY2030. From the results, we found that the MSW treatment system in which municipalities form communal MSW treatment mostly has an advantage than the municipality-based MSW treatment system in which municipalities treat MSW by themselves. We also found the trade-off relationship in the results; a system giving priority to gasification and melting facilities decreases the amount of final disposal and cost and increases GHG emissions, while another system giving priority to stoker type grate facility decreases GHG emissions and cost and increases the amount of final disposal. However this trade-off relationship is solved by enhancing waste segregation and/or bio-methanation of kitchen garbage. Additionally, we calculated the indicator value of environmental impact by the Distance-to-target method, and we evaluated a relationship between the indicator value and the cost. As the result, scenario involving the region-based MSW treatment system with bio-methanation is selected as a desirable MSW management system if reduction of final disposal is prioritize as the MSW treatment policy.
    Conclusions. In the actual fields, it is required not only quantatative evaluation environmental impact and cost but also qualitative investigation such as site selection of waste treatment facilities considering NIMBY phenomenon. Nonetheless, the methodology proposed in this paper is effective for local municipalities’ decision support.
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  • Tatsuo HISHINUMA, Akio SHIMIZU, Cuifen YANG, Yutaka GENCHI
    2009 Volume 5 Issue 1 Pages 68-78
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Objectives. From the viewpoint of importance to construct local livestock manure treatment and utilization system with low environmental impact, there was required planning local manure treatment system by quantitative and comprehensive evaluation on environmental aspects and cost. We evaluated local dairy cow manure treatment and utilization system introducing centralized biogas plant using life cycle assessment (LCA) and cost analysis with optimization software and database construction on geographic information system (GIS) to confirm availability of LCA approach for local manure treatment system planning.
    Results and Discussion. LCA approach was applied to case study, dairy cow manure treatment and utilization system at Yamada town in Chiba. As the results, it revealed that urine purification process at current manure treatment system was large impact at GHG emission. From the results of comparing GHG emission and total cost at each scenario, the alternative manure treatment and utilization system, utilizing manure compost depot for individual farm and introducing centralized biogas plant at west area was effective to reduce GHG emission. This approach was able to show the different types of equipments selection at system planning by objectives of scenario conditions. And it indicated introducing location for centralized biogas plant utilization, considered with nitrogen demands at local agricultural land. Furthermore, it calculated life cycle GHG emission by applying LCA including analyzing relation and link of several processes.
    Conclusions. We showed LCA approach, using GIS and optimization software, is able to consider local livestock manure treatment and utilization system planning for low environmental impacts.
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Technical Report
  • Mineo TSURUMAKI
    2009 Volume 5 Issue 1 Pages 79-85
    Published: 2009
    Released: December 15, 2019
    JOURNALS FREE ACCESS

    Objective. It is thought that LCA becomes one of the main methodology as research on the environmental influence in the planning stage of the infrastructure development. But there is a problem that it is difficult to collect the necessary detailed input / output data for inventory analysis to apply LCA on a planning stage. The purpose of this report is to suggest methodology to be based on a life cycle thinking by solving this problem.
    Results and discussion. Many LCI studies about many kind of sewage treatment facilities had been done. At first, data for the planning got from those studies are gathered and arranged as basic units on this study. Next, these basic units are applied to sewage treatment plan of a small village as a case study and it is examined that the application of the methodology is possible.
    Conclusion. It is shown by the case study that the methodology which has been examined in this study enables to consider life cycle environmental impacts on the planning stage of sewage treatment system and it is also clear that collection of further data and improvement of the precision are necessary.

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Note
General Articles
  • Ichiro FUKUHARA, Hiroki HONDO
    2009 Volume 5 Issue 1 Pages 89-101
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Background, Aim and Scope. Matrix-based life cycle inventory analysis is effective to evaluate environmental impacts of systems including closed–loops (e.g. recycling). However, the matrix method has not yet been widely used because it is complicated and difficult for most LCA practitioners to adequately make a regular coefficient matrix from input/output data of processes. Therefore, this study aims to develop a general method to make a unique, regular coefficient matrix for supporting the use of the matrix method.
    Methods. First, five types of basic components are newly defined to express a product system. The combination of these five components allows for describing an arbitrary product system. Second, a system that is re-described using the five components can be dealt with as a geometrical figure that is expressed using the abstract concepts of nodes and edges in the graph theory. Finally, a regular coefficient matrix is made by analyzing geometrical relationships between nodes and edges.
    Results. It was proved that a unique, regular coefficient matrix can be obtained if the geometrical figure corresponding to a product system is a planar graph. An algorithm to make such a coefficient matrix was formulated using Euler's polyhedron theory, based on balance equations of flows of goods (e.g. energy, materials) in a system studied. The validity of the proposed algorithm was demonstrated by applying the algorithm to a simple, numerical example: a product system including closed recycling.
    Discussion and Conclusions. An advantage of the developed method is that the complicated flows of goods in a product system studied can be reduced to an abstract geometrical figure according to mathematically simple rules. This means that computers can easily generate a unique, regular coefficient matrix automatically from input/output data of processes in a product system. We plan to create software based on the proposed algorithm, which enables LCA practitioners to easily perform the matrix-based LCA without making a coefficient matrix on their own.
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  • Yasuhiko WADA, Takuma OKUMOTO, Nariaki WADA
    2009 Volume 5 Issue 1 Pages 102-112
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Objective. To increase reduction in amounts of final disposal of waste and to improve the recycling rate, environmental loads and costs are weighed in this study, giving attention to the presence or absence of separate collection of plastic containers and packages for collection and gasification melting methods, and to stoker + ash melting method as an intermediate treatment.
    Results and Discussion. Results show that the gasification melting method and stoker + ash melting method should be selected appropriately depending on the facility’s incineration capacity. Furthermore, influences of the presence or absence of separate collection of other plastics on environmental loads and costs should not be great.
    Conclusions. Using the stoker + ash melting method, power consumption is less, as is the trend of environmental loading, than those of the gasification melting method. Although no great cost difference is apparent up to annual incineration amounts of about 60 kt, gasification melting method gives lower costs for amounts exceeding that level.
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  • Shihoko NEMOTO
    2009 Volume 5 Issue 1 Pages 113-121
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Objective. Although several studies have been conducted to evaluate CO2 emissions associated with the distribution of food, such studies have generally focused on emissions that occurred as a result of transportation from points of production to consumers. Few studies have evaluated the CO2 emissions from food that occur during transportation between facilities and storage at various facilities and stores. Therefore, this study is conducted to evaluate the CO2 emissions of foods using LCI analysis at each point throughout the distribution channels from points of production to individual consumers. These points also include distribution centers, facilities in which food is preserved, cut, packaged and sorted, retail stores, and delivery to a consumer’s home. Estimation of the CO2 emissions of foods throughout their distribution channels enables identification of the stage at which the most CO2 is emitted during food distribution. In addition, the analysis conducted here can be used to compare CO2 emissions at distribution channels with other stages of the life cycle of the foods evaluated.
    Materials and Methods. All analyses conducted in this study were based on an LCI analysis. The data evaluated in this study include the transported distance and power consumption associated with food at each point throughout the distribution channels. All data used in this study were provided by the Consumer’s Cooperative of Tokyo (CO-OP Tokyo). The CO2 emissions associated with food sold at a store and food that is delivered directly to consumers’ homes were then estimated based on cases where individuals who walk to stores or have their food delivered to homes in Kokubunji. Fresh tomatoes and fresh pork were selected for this study because they were the vegetables and meats with the greatest consumption in 2007 based on consumer-spending according to the Family Income and Expenditure Survey in Japan.
    Results and Discussion. The results of this study were as follows: 1. CO2 emissions for foods that are transported by air are very high. 2: The amount of CO2 emissions associated with tomatoes that are delivered to the consumer’s home is 150g-CO2/kg, whereas 242g-CO2/kg are associated with store-bought tomatoes. This difference occurred because 137 g-CO2/kg are emitted during refrigerating for storage and display at the retail store. These findings indicate that home-delivery of food is more environmentally friendly than purchasing food at the store. 3: In the case of greenhouse tomatoes produced in Kumamoto Prefecture and sold at the store in Kokubunji, a total of 1,254g-CO2/kg are emitted from production to sale at the store, and 14% of these emissions occur at the store. In the case of fresh pork produced in Kagoshima Prefecture and sold at the store in Kokubunji, a total of 6,545g-CO2/kg are emitted from production to sale at the store, and 8% of these emissions occur at the store.
    Conclusions. CO2 emissions differ significantly according to the various means of transportation, and sales. It is essential that retail stores sell their products only after determining ways of reducing CO2 emissions and selecting products that are produced and distributed using processes that reduce the amount of CO2 emitted. Furthermore, the use of labels detailing the CO2 emissions associated with foods should be considered.
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  • Yoshiyuki HONDO, Hideki KOBAYASHI
    2009 Volume 5 Issue 1 Pages 122-130
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Objective. Recently, “sustainable production and consumption” has been advocated. It is an approach from not only the perspective of “sustainable production”, which has already been employed, but also from the perspective of consumption with a view to achieving sustainability. The “rebound effect” is discussed from the perspective of “sustainable consumption”. In General, rebound effect means secondary environmental load derived from efficiency improvement. Several types of rebound effect have been reported. For instance, when a new goods or service generate surplus time and cost, they might be spent on the other action that brings about large environmental load. According to Greening (2000), such type of rebound effect is called “indirect rebound effect”. In this paper, we propose a new method of estimating the indirect rebound effect that utilizes a consumer behavior model and embodied intensity data of behavior. This mathematical model is based on the entropy principle from the field of information theory. The model calculates the every day life pattern of a target group on the basis of statistical data on behavior when an event brings about the rebound effect under time and budget constraints. The environmental load resulting from change in behavior can be estimated.
    Results and Discussion. The subject of our case study is teleworking and the rebound effect for the time generated by telecommuting was presumed. The case study reflects the fact that the change in life behavior pattern attributable to telecommuting leads to a reduction in CO2 emissions as a result of the estimation even if the rebound effect attributable to telework is taken into account. There is an advantage in that the behavior of the target group can be represented on the basis of statistical data, although the proposed model has a limitation in that only the rebound effect under constraints of time and cost is considered.
    Conclusions. This paper proposed a new method of estimating the rebound effect and its usefulness was shown by the results of the case study of telework. By using this method, the rebound effect caused by life behavior pattern change of the target group can be estimated without questionnaire or utility function. We intend to extend this method so as to evaluate various situations in the future.
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  • Hirotaka KOMATA, Shigeichi YOSHIDA, Yukihiro KATO, Mitsuko TAKAYAMA
    2009 Volume 5 Issue 1 Pages 131-137
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Objective. Wood is generally considered to be an eco-friendly material because it is renewable and carbon-neutral. Wood is said to require less energy to produce than aluminum, steel and concrete. However, the environmental loads of wood have not been assessed on a life-cycle basis. In studying CO2 emissions of wood and wood products, it is necessary to use life-cycle assessment (LCA). In this study, we estimated the CO2 emissions based on life cycle inventory analysis for log production of Japanese larch from ground clearance to final cutting, using models of forest management for planted forest in Hokkaido.
    Results and Discussion. The CO2 emissions from log production were estimated to range from 6.1 kg/m3 to 15.2 kg/m3. In terms of the classes of site, the emissions were the greatest for second-class, followed by the first-class and the special-class. In terms of control of stands density, the emissions were lower for low-density than for medium-density. In using machinery to clear the ground, the emissions were the greatest for excavators with brush cutter attachments, followed by excavators with grapple rake attachments, bulldozers, and shoulder bush cutter. No significant differences in emissions were observed between the planting densities of 2000 trees/ha and 2500 trees/ha. Emissions from silviculture were found to differ greatly according to the machinery used to clear the ground; there were estimated to account for 3% to 29% of overall emissions.
    Conclusions. From the point of view of reducing the CO2 related to log production, it is better to afforest areas that are higher class, and to control the stands at low densities. Also, it is not recommended to use heavy machinery such as bulldozers and excavators to clear the ground. The CO2 emissions associated with log production were estimated to account for 0.8% to 2.0% of CO2 fixed in the log.
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  • Shinsuke MURAKAMI, Hitoshi OHSUGI, Rie MURAKAMI-SUZUKI, Aiko MUKAIDA, ...
    2009 Volume 5 Issue 1 Pages 138-144
    Published: 2009
    Released: August 01, 2012
    JOURNALS FREE ACCESS

    Objective. We have gradually shifted toward the sound-material cycle society, and achieved some positive results. There are many discussions on so-called E-waste cycles. The home appliance recycling law was established and enforced for relatively large size home appliances. However, there is no legislative scheme for the small size home appliance recycling, and the hibernating stock of these appliances has attracted much attention recently. In this paper, consumer behaviors on their mobile phones, such as average lifespan and the management of their EoL (End of Life) mobile phones, are analyzed with the questionnaire survey. Then, the results were utilized for the estimation of both in-Use and hibernating stocks of mobile phones in Japan.
    Results and Discussion. We found out that the average lifespan has remained unchanged, while there is a report that the average duration of use has increased. In addition, the number of people who handed their EoL phones for recycling has obviously decreased for this decade. In the end, the amount of the stocks of mobile phones hibernating in the consumer’s house is estimated as 167 million units at the end of 2007.
    Conclusion. These 167million units of hibernating mobile phones make up 45 percent of the aggregated amount of EoL mobile phones in Japan and we need to take measures to this hibernating stock.
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