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Study on estimation of soil water status by using microwave remote sensing

Research Project

Project/Area Number 09660259
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Irrigation, drainage and rural engineering/Rural planning
Research InstitutionKagawa University

Principal Investigator

ISHIDA Tomoyuki  Kagawa University, Department of Agriculture, Associate Professor, 農学部, 助教授 (40184535)

Project Period (FY) 1997 – 1998
Project Status Completed (Fiscal Year 1998)
Budget Amount *help
¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
KeywordsBOUND WATER / DIELECTRIC RELAXATION / COMPLEX PERMITTIVITY / CLAY / INTERFACIAL POLARIZATION
Research Abstract

The dielectric behavior of moist kaolinite, montmorillonite, allophane and imogolite was examined with a time domain reflectometry method in a wide frequency range of 10^3 - 10^<10> Hz. The peak locates at approximately 10 MHz. It is concluded that the structure of bound water differs between the sheet silicate and amorphous minerals. The interfacial polarization in the diffuse double layer was found only in montmorillonite and kaolinite samples, indicating that the Maxwell-Wagner and surface polarization effects cannot be regarded as a general mechanism responsible for the interfacial polarization of all the clay-water systems.
Dielectric measurements were performed on silica, alumina and silica-alumina gel suspensions. For all the gels, a relaxation peak due to bound water was observed. This peak locates around 1-10 MHz. The silica and alumina gels have a different bound water structure The silica-alumina gels exhibit two different peaks other than the peak of bulk water. It is suggested that both peaks are caused by the orientation of bound water molecules.
Dielectric measurements were performed on montmorillonite, allophane and imogolite suspensions under various pH conditions. Allophane has two peaks, indicating that its peaks are very similar to those of silica-alumina eels. Imogolite has only one peak. The relaxation strength of montmorillonite is greater than that of the other two clays. For all the clays, the relaxation strength depended on the pH.A change in the relaxation strength is explained in terms of the different network structures of the clay particles. It is suggested that bound water influences on the network structure formation.

Report

(3 results)
  • 1998 Annual Research Report   Final Research Report Summary
  • 1997 Annual Research Report
  • Research Products

    (9 results)

All Other

All Publications (9 results)

  • [Publications] 石田 智之: "土壌の誘電緩和" 農業土木学会誌. 66. 62-62 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] T.Ishida and T.Makino: "Microwave Dielectric Relaxation of Bound Water to Silica, Alumina, and Silica-Alumina Gel Suspenusions" 211. 144-151 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] T.Ishida and T.Makino: "Effects of pH on Dielectric Relaxation of Moutmorillonite, Allophane, and Imogolita.Suspensions" Journal of Colloid and Interface Science. 211. 152-161 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Tomoyuki Ishida: "Dielectric Relaxation of soils" Nougyoudoboku Gakkaisi. 66. 62 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Tomoyuki Ishida, Tomoyuki Makino: "Microwave dielectric relaxation of bound water to silica, alumina, silica-alumina gel suspensions" Journal of Colloid and Interface Science.212. 144-151 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Tomoyuki Ishida, Tomoyuki Makino: "Effects of pH dielectric relaxation of montmorillonite, allophane, and imogolite suspensions." Journal of Colloid and Interface Science.212. 152-161 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] T.Ishida and T.Makino: "Microwave Dielectric Relaxation of Bound Water to Silica,Alumina,and Silica Alumina Gel Suspensions" Journal of Colloid and Interface Science. 211(印刷中). (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] T.Ishida and T.Makino: "Effects of pH on Dielectric Relaxation of Montinorillonite,Allophane,and Imogalite Suspensions" Journal of Colloid and Interface Science. 211(印刷中). (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] 石田智之: "土壌の誘電緩和" 農業土木学会誌. 66・2. 62-62 (1998)

    • Related Report
      1997 Annual Research Report

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Published: 1998-04-01   Modified: 2016-04-21  

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