Donald R. Rowe, Ph.D., is President of D.R. Rowe Engineering Services, Inc., Bowling Green, Kentucky. He received his B.S. degree (1948) in Civil Engineering from the University of Saskatchewan, Canada and his M.S. (1962) and Ph.D. degrees (1965) from The University of Texas at Austin.Isam Mohammed Abdel-Magid, Ph.D., is Associate Professor in the Department of Civil Engineering of the University of Khartuum, Sudan on secondment to the Department of Civil Engineering at Sultan Qaboos University, Muscat, Sultanate of Oman.