1. Physics Department Faculty of Science University of Malaya Kuala Lumpur 50603 Malaysia
2. Chemical Engineering Department Faculty of Engineering University of Malaya Kuala Lumpur 50603 Malaysia
3. Electrical Engineering Department Faculty of Engineering University of Malaya Kuala Lumpur 50603 Malaysia
4. Higher Institution Centre of Excellence (HICoE) UM Power Energy Dedicated Advanced Centre (UMPEDAC), Level 4 Wisma R&D University of Malaya Kuala Lumpur 59990 Malaysia