1. Department of Physics, Faculty of Science, King Abdulaziz University, 21589 Jeddah, Saudi Arabia
2. Department of Physics, Faculty of Science, University of Tabuk, 71491 Tabuk, Saudi Arabia
3. Department of Polymer Engineering, University of Chemical Technology and Metallurgy, 1756 Sofia, Bulgaria
4. Institute of Chemical Engineering, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria