1. Center of Excellence Geopolymer & Green Technology (CEGeoGTech), Universiti Malaysia Perlis (UniMAP), 01000 Kangar, Perlis, Malaysia
2. School of Manufacturing Engineering, Universiti Malaysia Perlis (UniMAP), Pauh Putra Campus, 02600 Arau, Perlis Malaysia
3. Department of Physics, Faculty of Science, UniversitiTeknologi Malaysia, Skudai, Johor, Malaysia