1. School of Chemical Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia
2. Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016, India
3. Department of PetroChemical Engineering, Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, 31900, Kampar, Perak Malaysia
4. Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States