Altman Susan J, Peplinski William J, Rivers Mark L
Geohydrology Department, Sandia National Laboratories, Albuquerque, NM 87185-0735, USA.
J Contam Hydrol. 2005 Jul;78(3):167-83. doi: 10.1016/j.jconhyd.2005.05.004.
Synchrotron-source X-ray computerized microtomography (CMT) is evaluated as a method to visualize transport processes. We conclude that CMT is adequate for visualization of transport experiments if the right conditions exist. Namely, 1) not much more than one-order-of-magnitude range in concentration data is needed for the study, 2) the pore space in the samples are greater than approximately 2--50 mum, depending on the sample size and system setup; 3) the sample is fine-grained enough so that a representative elemental volume (REV) can be contained by a 2--10 mm diameter sample, and 4) the transport process is slow enough that significant changes do not occur within the 25--50 min (and possibly less in the future) needed to collect data for one three-dimensional image. Absorption edge difference imaging (AEDI) in association with CMT is introduced as a method to enhance pore-space visualization. We successfully imaged the pore space in a low-porosity granodiorite, diorite and fine-grained granite cores and a higher-porosity soil aggregate sample. We found that the pore space important to transport in the core samples was smaller than what we were able to visualize with CMT. We also made rudimentary associations of minerals with pore-space location.
同步辐射源X射线计算机断层扫描（CMT）被评估为一种可视化传输过程的方法。我们得出结论，如果存在合适的条件，CMT足以用于传输实验的可视化。具体而言，1）该研究所需的浓度数据范围不超过一个数量级；2）根据样品大小和系统设置，样品中的孔隙空间大于约2 - 50微米；3）样品粒度足够细，以便直径2 - 10毫米的样品能够包含一个代表性的单元体（REV）；4）传输过程足够缓慢，以至于在采集一幅三维图像所需的25 - 50分钟（未来可能更少）内不会发生显著变化。引入与CMT相关联的吸收边差异成像（AEDI）作为一种增强孔隙空间可视化的方法。我们成功地对低孔隙度花岗闪长岩、闪长岩和细粒花岗岩岩芯以及高孔隙度土壤团聚体样品中的孔隙空间进行了成像。我们发现，岩芯样品中对传输重要的孔隙空间比我们用CMT能够可视化的要小。我们还对矿物与孔隙空间位置进行了初步关联。
