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@INPROCEEDINGS{Duschl:150842,
      author       = {Duschl, Markus and Pohlmeier, Andreas and Brox, Tim and
                      Galvosas, Petrik and Vereecken, Harry},
      title        = {{N}uclear magnetic resonance relaxation and diffusion
                      measurements as a proxy for soil properties},
      reportid     = {FZJ-2014-00881},
      year         = {2013},
      abstract     = {Nuclear Magnetic Resonance (NMR) relaxation and NMR
                      diffusion measurements are two of a series of fast and
                      non-invasive NMR applications widely used e.g. as well
                      logging tools in petroleum exploration [1]. For experiments
                      with water, NMR relaxation measures the relaxation behaviour
                      of former excited water molecules, and NMR diffusion
                      evaluates the self-diffusion of water. Applied in porous
                      media, both relaxation and diffusion measurements depend on
                      intrinsic properties of the media like pore size
                      distribution, connectivity and tortuosity of the pores, and
                      water saturation [2, 3]. Thus, NMR can be used to
                      characterise the pore space of porous media not only in
                      consolidated sediments but also in soil. The physical
                      principle behind is the relaxation of water molecules in an
                      external magnetic field after excitation. In porous media
                      water molecules in a surface layer of the pores relax faster
                      than the molecules in bulk water because of interactions
                      with the pore wall. Thus, the relaxation in smaller pores is
                      generally faster than in bigger pores resulting in a
                      relaxation time distribution for porous media with a range
                      of pore sizes like soil [4]. In NMR diffusion experiments,
                      there is an additional encoding of water molecules by
                      application of a magnetic field gradient. Subsequent storage
                      of the magnetization and decoding enables the determination
                      of the mean square displacement and therefore of the
                      self-diffusion of the water molecules [5]. Employing various
                      relaxation and diffusion experiments, we get a measure of
                      the surface to volume ratio of the pores and the tortuosity
                      of the media. In this work, we show the characterisation of
                      a set of sand and soil samples covering a wide range of
                      textural classes by NMR methods. Relaxation times were
                      monitored by the Carr-Purcell-Meiboom-Gill sequence and
                      analysed using inverse Laplace transformation. Apparent
                      self-diffusion constants were detected by a 13-intervall
                      pulse sequence and variation of the storage time. We
                      correlated the results with various soil properties like
                      texture, water retention parameters, and hydraulic
                      conductivity. This way we show that we can predict soil
                      properties by NMR measurements and that we are able use
                      results of NMR measurements as a proxy without the need of
                      direct measurements.},
      month         = {Apr},
      date          = {2013-04-07},
      organization  = {European Geosciences Union General
                       Assembly 2013, Vienna (Austria), 7 Apr
                       2013 - 12 Apr 2013},
      subtyp        = {After Call},
      cin          = {IBG-3},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {246 - Modelling and Monitoring Terrestrial Systems: Methods
                      and Technologies (POF2-246) / BMBF-0315532A - CROP.SENSe.net
                      (BMBF-0315532A)},
      pid          = {G:(DE-HGF)POF2-246 / G:(DE-Juel1)BMBF-0315532A},
      typ          = {PUB:(DE-HGF)6},
      url          = {https://juser.fz-juelich.de/record/150842},
}