1. Universiti Tun Hussein Onn, Faculty of Engineering Technology, Pagoh, Johor, Malaysia
2. Universiti Tun Hussein Onn, Centre for Diploma Studies, Pagoh, Johor, Malaysia
3. Universiti Malaysia Perlis (UniMAP), Centre of Excellence Geopolym er & Green Technology (CEGeoGTech), 01000 Perlis, Malaysia
4. Częstochowa University of Technology, Faculty of Production Engineering and Materials Technology, Department of Physics, 19 Armii KrajowejAv., 42-200 Częstochowa