1. Dept. of Civ. and Envir. Engrg., Imperial Coll. of Sci., Technol., and Medicine, London SW7 2BU UK; formerly, Water Technology International Corp., Burlington, ON, L7R 4L7 Canada. E-mail: j.stegemann@ic.ac.uk
2. Dept. of Civ. and Envir. Engrg., Louisiana State Univ., Baton Rouge, LA.
3. Water Technology International Corp., Burlington, ON, L7R 4L7 Canada.
4. Ctr. for Advanced Microstruct. and Devices, Louisiana State Univ., Baton Rouge, LA.