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@PHDTHESIS{Spindler:17290,
      author       = {Spindler, Natascha},
      title        = {{D}iffusion and {F}low {I}nvestigations innatural {P}orous
                      {M}edia by {N}uclear {M}agnetic {R}esonance {I}maging},
      volume       = {112},
      issn         = {1866-1793},
      school       = {RWTH Aachen},
      type         = {Dr. (FH)},
      address      = {Jülich},
      publisher    = {Foschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {PreJuSER-17290},
      isbn         = {978-3-89336-719},
      series       = {Schriften des Forschungszentrums Jülich : Energie $\&$
                      Umwelt / Energy $\&$ Environment},
      pages        = {VIII, 144 S.},
      year         = {2011},
      note         = {Record converted from VDB: 12.11.2012; RWTH Aachen, Diss.,
                      2011},
      abstract     = {Climate change and a growing global population impose
                      severe pressure on securing the supply of nutrition to
                      mankind. A crucial aspect thereby is the possibility to
                      adopt the cultivation of crops to the changing climatic
                      conditions. This is a strong motivation for being interested
                      in root water uptake of plants. To obtain a better
                      understanding of these mechanisms, analysis of water motion
                      inside and towards plant roots in natural soil are
                      essential. This work aims on the determination of water
                      motion in natural porous media such as roots and soil using
                      different techniques of nuclear magnetic resonance (NMR).
                      NMR is known from medical diagnosis and allows non-invasive
                      investigations of natural soil and intact plants. Therefore,
                      NMR is best suited for investigating root water uptake
                      processes. Since modeling of root water uptake processes
                      requires an unambiguous three-dimensional reconstruction of
                      the root skeleton, magnetic resonance imaging (MRI) is an
                      appropriate technique for this challenge. From the spatial
                      analysis of the answer of the sample to excitation with
                      radio frequency (rf) pulses, the water distribution and
                      motion inside the sample can be determined. This thesis
                      shows how common imaging techniques introduce gaps in
                      reconstructed roots due to susceptibility effects. To
                      compensate for these effects, diffusion tensor imaging (DTI)
                      was transformed to the requirements of plant roots and
                      successfully applied for the first time. DTI is also an
                      NMR-technique known from medical research, which detects
                      local diffusive displacements of water molecules with high
                      spatial resolution. Restrictions such as cell walls in plant
                      roots limit the diffusion. If such restrictions are
                      spatially dependent, diffusion is called anisotropic. This
                      can be mathematically expressed by a tensor, describing the
                      local anisotropy. DTI determines the diffusion tensors at
                      different positions in the sample. Since DTI on plant roots
                      shows typically a low signal to noise ratio (SNR), this work
                      presents a new approach for data analyzing beside the common
                      medical procedure. In the end, it was possible to visualize
                      a single root of the root skeleton three-dimensionally by
                      measuring diffusion tensors inside the root. [...]},
      cin          = {IBG-3},
      ddc          = {333.7},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      url          = {https://juser.fz-juelich.de/record/17290},
}