1. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Tennessee, Knoxville, TN 37996.
2. Postdoctoral Research Assistant, Joint Institute of Computational Sciences at Oak Ridge National Laboratory, Oak Ridge, TN 37831-6173.
3. Professor, Dept. of Biosystems Engineering and Soil Science, Univ. of Tennessee, Knoxville, TN 37996 (corresponding author).