1. University of Genoa Department of Civil, Chemical and Environmental Engineering via Opera Pia 15 16145 Genoa Italy
2. University of Ha'il Department of Chemical Engineering College of Engineering P.O. Box 2440 81441 Ha'il Saudi Arabia
3. King Saud University Geology and Geophysics Department P.O. Box 2455 11451 Riyadh Saudi Arabia
4. Al Neelain University Department of Chemical Engineering Faculty of Engineering Khartoum Sudan