1. PhD Candidate, Dept. of Civil and Environmental Engineering, Univ. of Pittsburgh, 975 Benedum Hall, Pittsburgh, PA 15261.
2. Postdoctoral Scientist, Connecticut Agricultural Experimental Station, 123 Huntington St., P. O. Box 1106, New Haven, CT 06504.
3. PhD Candidate, Dept. of Civil and Environmental Engineering, Univ. of Pittsburgh, 968 Benedum Hall, Pittsburgh, PA 15261.
4. Associate Professor, Dept. of Chemistry, Temple Univ., 1901 N. 13th St., Philadelphia, PA 19122.
5. Professor, Dept. of Civil and Environmental Engineering, Univ. of Pittsburgh, 943 Benedum Hall, Pittsburgh, PA 15261 (corresponding author).