1. Faculty of Science, Beirut Arab University, P.O. Box 11-5020, Beirut 1107 2809, Lebanon
2. Laboratory of Interfaces and Advanced Materials, Faculty of Science, University of Monastir, Monastir 5019, Tunisia
3. Department of Mathematics and Natural Sciences, School of Arts and Sciences, American University of Ras Al Khaimah, P.O. Box 10021, Ras Al Khaimah 10021, UAE