1. Assoc. Prof., Dept. of Civ. and Mineral Engrg., Univ. of Minnesota, Minneapolis, Minn.
2. Environmental Engr., Union Carbide Corp., Chemical and Plastics Div., South Charleston, Va.
3. Asst. Prof., Dept. of Civ. Engrg., Univ of Illinois, Urbana, Ill.