1. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Washington, Seattle, WA 98195 (corresponding author).
2. Presently, Application Engineer, Kubota Membrane USA Corporation, 14824 NE 95th St., Bldg. 6, Redmond, WA 9805; Dept. of Civil and Environmental Engineering, Univ. of Washington, Seattle, WA 98195.
3. Associate Professor, Dept. of Chemistry and Dept. of Civil Engineering, Jordan Univ. of Science and Technology, Irbid 22110, Jordan.