title: NMR velocimetry with 13-interval stimulated echo multi-slice imaging in natural porous media under low flow rates.
abstract: Characterization and quantification of root water uptake processes play a key role in understanding and managing the effects of global climate change on agricultural production and ecosystem dynamics. Part of this understanding is related to the flow of water towards plant roots in soils. In this study we demonstrate for the first time, to our knowledge, that fluid flow in the voids of the pore space of a model soil system (natural sand) can be detected and mapped to an NMR image for mean flows as low as 0.06 mm/s even under the influence of internal magnetic field gradients. To accomplish this we combined multi-slice imaging with a 13-interval pulse sequence to the NMR pulse sequence 13-interval stimulated echo multi-slice imaging (13-interval STEMSI). The result is a largely reduced influence of the internal magnetic field gradients, leading to an improved signal-to-noise ratio which in turn enables one to acquire velocity maps where conventional stimulated echo methods fail.
authors.affiliation: Forschungszentrum Juelich, Institute of Bio- and Geosciences-Agrosphere, 52425 Juelich, Germany.
authors.forename: Natascha
authors.initials: N
authors.lastname: Spindler
authors.forename: Petrik
authors.initials: P
authors.lastname: Galvosas
authors.forename: Andreas
authors.initials: A
authors.lastname: Pohlmeier
authors.forename: Harry
authors.initials: H
authors.lastname: Vereecken
mesh_terms: D000465:Algorithms; D016477:Artifacts; D002138:Calibration; D003198:Computer Simulation; D004574:Electromagnetic Fields; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D016011:Normal Distribution; D018517:Plant Roots / Q000378:metabolism*; D016062:Porosity; D059629:Signal-To-Noise Ratio; D012822:Silicon Dioxide; D012987:Soil / Q000032:analysis; D014867:Water / Q000378:metabolism
chemical_list: D012987:Soil; D014867:Water; D012822:Silicon Dioxide