| Project/Area Number |
06660294
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | IBARAKI UNIVERSITY |
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Principal Investigator |
KARUBE Jutaro Ibaraki University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (10007768)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAISHI Katsuya Ibaraki University, Faculty of Agriculture, Assistant Professor, 農学部, 助手 (40180236)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Allophane / Charge / Water characteristic curve / Clay |
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| Research Abstract |
Allophane colloid, separated from air-dried soil, showed lower water content than that from fresh soil by 23-29% over the range from -1.4JKg^<-1> to -800JKg^<-1> of matric potential. Since both samples were prepared to be less than 50 nm in Stokes'diameter, this irreversibility was ascribed to submicroscopic irreversible aggregation. Water characteristic curves of allophane colloid separated from fresh soil were coincident regardless of different pHs, i.e.different surface charges below -100JKg^<-1>, and diverged gradually above -100JKg^<-1>, from 3.1 nm in average particle separation. The lower the sbsolute value of allophane charge was, the higher the water content was above -100JKg^<-1>. Water characteristic curves of allophane were irreversible except for highly charged one above -100JKg^<-1>. The water content of imogolite was higher that of montmorillionite at any matric potential, and showed more than twice as much as that of allophane below -10JKg^<-1>. The water content of allophane was higher than that of montmorillonite above -400JKg^<-1>. When montmorillonite was mixed with allophanic clay, the water content became higher than either of clays in the range from -100JKg^<-1> to -800JKg^<-1> due to intercalation. The high water retentivity of imogolite can be explained not only in terms of it's high specific surface area but also submicroscopic pores made up by intertwined fibrous particles.
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