Journal of the Japan Institute of Energy
Online ISSN : 1882-6121
Print ISSN : 0916-8753
ISSN-L : 0916-8753
Volume 86 , Issue 12
Showing 1-3 articles out of 3 articles from the selected issue
Original Paper
  • Yosuke TONO, Hisashi MIYAFUJI, Masashi SHIBATA, Shiro SAKA
    2007 Volume 86 Issue 12 Pages 973-977
    Published: December 20, 2007
    Released: June 27, 2008
    Studied were inorganic constituents of the ash from various parts of oil palm (Elaeis guineensis) such as trunk, frond, mesocarp, endocarp (shell), kernel cake and empty fruit bunch (EFB) by scanning electron microscopy equipped with energy-dispersive X-ray analysis (SEM-EDXA). As a result, K, Si, Na, Ca, S, P and Mg were found as elements in all parts of the oil palm studied. Particularly, Si and K were abundant in the trunk, shell, mesocarp and kernel cake, while the frond and kernel cake contained, respectively, K, Ca and P in a large quantity. The elements of Cl, Fe and Al were, however, detected only in some parts.
    There existed three types of shapes in the ash such as needle, sphere and fluffy substances in the oil palm. However, the needles were found only in the trunk with spheres. In some other parts such as frond, shell, kernel cake and EFB, fluffy and sphere substances were found in their ash, while in the mesocarp, only fluffy substances were observed. For the needles and spheres, elements of Na and Si were, respectively, found to be localized, whereas fluffy substances contained all of the elements such as K, Si, Na, Ca, S, P and Mg with sometime Cl, Fe and Al.
    These elements found are important and prerequisite for the healthy growth of the oil palm. Therefore, it may be concluded that, upon the whole utilization of the oil palm, inorganic constituents found in this study must be returned to the plantation site. Otherwise, the same has to be compensated to its site for sustainable development.
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  • Tomoya KATO, Ryo YOSHIIE, Shigeyuki UEMIYA, Tsukasa YOSHIDA, Kiyotaka ...
    2007 Volume 86 Issue 12 Pages 978-986
    Published: December 20, 2007
    Released: June 27, 2008
    The use of dye-sensitized solar cells (DSC) with zinc oxide as electrodes is expected to contribute to a CO2 emission-reduction. In this study we examined the CO2 emission-reduction effect by using Life Cycle Assessment (LCA). The Life Cycle Inventory (LCI) was estimated with the LCA software “AIST-LCA ver.4”. LCI was applied to predict the CO2 emission per unit of generated electricity for several potential technical developments of DSC. And the CO2 pay-back time for such solar cells based on conventional power generation systems in Japan was investigated, compared with those for polysilicon solar cells. In addition, according to several solar cell installation scenarios, the installation area and the number of years required by DSC to exceed the polysilicon solar cell in the amount of CO2 reduction were estimated. It was confirmed that DSC technologies are potentially capable of exceeding the polysilicon solar cell in the level of CO2 reduction. The LCI results have lead to an understanding of the differences and factors that influence them. This study offers many important suggestions that will be helpful in making decisions about future research and development into DSC.
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  • Gento MOGI, Masanari KOIKE, Taro SAKAZUME, Narisuke NISHIIKE, Ben McNe ...
    2007 Volume 86 Issue 12 Pages 987-994
    Published: December 20, 2007
    Released: June 27, 2008
    World crude oil production forecast has been predicted based on several production scenarios of the Middle East oil producers and production profiles as well as discovery functions of known and yet to find oil fields in other regions. The global production forecast as well as the timing of peak oil substantially depends on the production scenario of the Middle East producers, so that the timing of the peak oil cannot be specified. On the other hand, it has also been found out that the rates of decrease in the production after peak oil varies more than double according to different production scenarios of the Middle East producers.
    Following three scenarios have been assumed for production forecast of Middle East producers, namely (i) keep their current production level; (ii) increase production level to cope with the growth of the global demand; (iii) adjust production rate to keep the current global production level; all these three until R/P ratio decreases down to 25 years, thereafter decreasing the production to keep the same level of the R/P ratio. The starting period of declining in the production as well as the rate of decrease in production after it largely depends on the above scenarios. The earliest decline in global production is elicited in case (i) as starting from year 2010, the second earliest in case (ii) as starting from year 2025, the latest in case (iii) as starting from 2033 (or 2034 in case of growing exploration activities). On the other hand, the rate of decrease in the production is most moderate in case (i), initially declining at less than 2% per year. Fatalistic rate of decrease in the production has been suggested in case (ii), initially declining at more than 4% per year.
    The intensity of exploration activities represented by the number of wild cat wells, outside Middle East and US except Alaska, in the range under consideration, does not largely affect the global production forecast. But it still has limited but certain effect to eliminate the rate of decrease in production once after peak oil has been emerged.
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