1. Faculty of Engineering, May University in Cairo, Cairo 11235, Egypt
2. Laboratory of Organic Matter Physics, University of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia
3. Department of Physics, The American University in Cairo, Cairo 11835, Egypt
4. Dravske elektrarne Maribor, Obrežna ulica 170, 2000 Maribor, Slovenia