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| Titel |
NMR properties of partially saturated porous silica glasses |
| VerfasserIn |
Eugen Wiens, Norbert Klitzsch, Oliver Mohnke |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250039694
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| Zusammenfassung |
| The signal responses of nuclear magnetic resonance (NMR) is sensitive to the inner surfaces
of the water filled porous media. Therefore this method is well suited to noninvasively
determine hydrological relevant parameters such as the pore radii distributions or hydraulic
permeability of fully and partially saturated rocks and soils. NMR exploits the relaxation of
the magnetization of fluids in the pore space of porous medium. In this work we study the
dependence of NMR signals on the inner structure of fully and partially saturated artificial
porous silica glasses (VitraPOR). The samples are characterized by an accurately
defined pore space with well known pore radii distributions and surface properties.
The mean pore sizes of the investigated samples range from 0.6 μm to 25 μm.
Laboratory NMR saturation recovery (T1) and CPMG (T2) measurements as well as
diffusion pulsed gradient mesurements have been carried out using a 3.91 MHz NMR
spectrometer. A homogeneous partial saturation down to 5 vol.% has been realized by
applying a uniform negative pressure gradient to the samples at each desaturation
step. Additionally the corresponding water retention curves have been recorded
and evaluated. On the basis of the results from these experiments the numerical
simulation of the pore network using the Delaunay tesselation approach with subsequent
simulations of NMR relaxation on the pore scale is performed in order to assess
structure, state and thus transport properties of fully and partially saturated soils. |
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