HR: 17:30h
AN: H12K-07    [PDF]
TI: Reconstructing the Pore Space of Sand Samples
AU: * Kaestner, A
EM: anders.kaestner@ito.umnw.ethz.ch
AF: Swiss Federal Institute of Technology Zuerich, Institute of terrestrial Ecology Grabenstr.11a, Schlieren, 8952 Switzerland
AU: Lehmann, P
EM: peter.lehmann@ito.umnw.ethz.ch
AF: Swiss Federal Institute of Technology Zuerich, Institute of terrestrial Ecology Grabenstr.11a, Schlieren, 8952 Switzerland
AU: Fluehler, H
EM: hannes.fluehler@ito.umnw.ethz
AF: Swiss Federal Institute of Technology Zuerich, Institute of terrestrial Ecology Grabenstr.11a, Schlieren, 8952 Switzerland
AU: Wyss, P
EM: peter.wyss@empa.ch
AF: Centre for Non-destructive Testing, Swiss Federal Laboratories for Materials Testing and Research, Ueberlandstr. 129, Duebendorf, 8600 Switzerland
AU: Beckmann, F
EM: felix.beckmann@gkss.de
AF: Institute for Materials Research Devision for Neutron- and Synchrotron Scattering, GKSS-Research Center c/o HASYLAB at DESY, Notkestr. 85, Hamburg, 22607 Germany
AB: The structure of the pore space is essential for flow and transport in soils. Size, shape and connectivity of the pores determine the distribution of air and water, pore water velocity and solute mixing. So, for a complete understanding of transport processes in soils, the pore geometry must be known. Some processes, for example the drainage of water, depend on narrow structures with sizes of a few micrometers. For this reason, a technique to measure 3D pore structures with high resolution is needed. This presentation will describe the image processing steps needed to provide a pore space with the highest possible fidelity to the measured sample. The projection data were acquired using an imaging system based on synchrotron radiation. This technique allows us to map the pore structure in the range of 10 microns. To transform the projection data into pore space volumes, a chain of actions involving back projection, the application of various filters to suppress noise and artifacts, and segmentation is needed. During experiments at the Swiss Light Source (SLS) we scanned sand samples with diameter 5 mm containing sand particles ranging from 100 to 300 microns with a voxel size of 3.5 microns. At the Hamburger Synchrotron Laboratory (HASYLAB) sand samples with diameter 15 mm containing particles ranging from 100 to 900 microns were mapped with a voxel size of 11 microns. In addition to the scanning of completely dry samples, we intend to investigate the water and air distribution for different degrees of water saturation. Comparing these measurements with numerical simulations, we hope to understand the processes of air and water distribution in more detail.
DE: 1875 Unsaturated zone
DE: 1894 Instruments and techniques
DE: 1899 General or miscellaneous
SC: Hydrology [H]
MN: 2003 Fall Meeting