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@ARTICLE{Pohlmeier:5532,
      author       = {Pohlmeier, A. and Haber-Pohlmeier, S. and Stapf, S.},
      title        = {{A} {F}ast {F}ield {C}ycling {N}uclear {M}agnetic
                      {R}esonance {R}elaxometry {S}tudy of {N}atural {S}oils},
      journal      = {Vadose zone journal},
      volume       = {8},
      issn         = {1539-1663},
      address      = {Madison, Wis.},
      publisher    = {SSSA},
      reportid     = {PreJuSER-5532},
      pages        = {735 - 742},
      year         = {2009},
      note         = {The authors thank the German research fund (DFG) for
                      financial support (Sta 511/4- 1, PO 746/2-1, and
                      Transregio/SFB32), F. Pauly and U. Lesten (ZAT, Research
                      Center Julich) for the recording CT images, C. Walraf
                      (ICG-4, Research Center Julich) for the BET measurements,
                      and J. Koestel and A.-P. Schmidt-Eisenlohr (ICG4, Research
                      Center Julich) 360 for the water retention curves of the
                      soils.},
      abstract     = {This study used nuclear magnetic resonance (NMR)
                      relaxometry at different Larmor frequencies to investigate
                      water dynamics in the pore space of natural porous media.
                      Spin-lattice NMR relaxation times (T-1) were determined in
                      purified fine sand and two natural soils, Kaldenkirchen
                      sandy loam and Merzenhausen silt loam, by means of fast
                      field This technique investigates relaxation processes as a
                      function of the Larmor frequency. in the 0.005 and 20 MHz,
                      yielding so-called relaxation dispersion curves (1/T-1 vs.
                      log.). The data were further by means of inverse Laplace
                      transformation to calculate the T-1 relaxation time
                      distribution functions. Only sand was characterized by
                      monomodal distribution with T-1 of about 1 s at 20 MHz,
                      whereas the natural soil showed multi modal distribution
                      functions in the range between 2 and 70 ms. With decreasing
                      Larmor frequency, all distribution functions kept their
                      shapes but were shifted to faster relaxation times. The
                      corresponding relaxation dispersion curves indicate
                      predominance of two-dimensional diffusion of water in the
                      soils, whereas in the sand, diffusion behaved like
                      unrestricted three-dimensional diffusion. In terms of the
                      Brownstein-Tarr model, in the T-1 relaxation times with
                      increasing silt and clay content can be explained by an
                      increase of the volume ratios (S/V) of these porous media,
                      i.e., by a decrease in the pore sizes. Finally, distribution
                      functions of size parameter V/S were obtained from the
                      spin-lattice relaxation time distributions by normalizing on
                      the specific surface area. They ranged from submicrometers
                      in the Merzenhausen soil to micrometers and submillimeters
                      in soil and fine sand, respectively.},
      keywords     = {J (WoSType)},
      cin          = {ICG-4},
      ddc          = {550},
      cid          = {I:(DE-Juel1)VDB793},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      shelfmark    = {Environmental Sciences / Soil Science / Water Resources},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000268871900020},
      doi          = {10.2136/vzj2008.0030},
      url          = {https://juser.fz-juelich.de/record/5532},
}