Item: Nondestructive collection of natural snow specimens for use with ct scan analysis
Title: Nondestructive collection of natural snow specimens for use with ct scan analysis
Proceedings: Proceedings of the 1998 International Snow Science Workshop, Sunriver, Oregon
Authors: Christopher Lundy and Edward E. Adams, Department of Civil Engineering, Montana State University
Abstract: Recently, CT (CAT) scanning technology has been utilized to analyze snow and ice samples. To facilitate applying this technology to natural snow, a procedure has been developed that allows snow specimens to be transported from an outdoor location to the laboratory for the purpose of CT imaging. A snow sample is first obtained in a tubular container. A screen is placed beneath the container, and dimethyl phthalate cooled to a temperature just below O°C is slowly poured in the top of the snow. The wetting front moves downward, filling the pore space and expelling air out the base of the specimen. Packing the sample in dry ice freezes the substance in the pore space, protecting the snow microstructure and prohibiting metamorphism during transportation. The methodology presented is intended for CT imaging, which offers a nondestructive means to investigate grain structure and intergranular bonding, but is also applicable to surface sectioning. CT scans demonstrate that this technique provides adequate penetration of the dimethyl phthalate into the interstitial pores to prevent structural damage or metamorphism of the snow. Differences in X-ray absorption provide distinction between the ice grains and the dimethyl phthalate filled pore space.
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Keywords: snow and ice, methods of sampling, snow cover structure, computed tomography
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