1. Lect., Dept. of Civ. Engrg., Indian Institute of Technology, Delhi, Hauz Khas, New Delhi, India 110 016. E-mail: bjalappat@yahoo.com or alappat@civil. iitd.ernet.in
2. Ret. Prof., Formerly, Dept. of Chemical Engrg., Indian Institute of Technology, Bombay, Powai, Mumbai, India 400 076.