1. Chemical Engineering Department; Universitas Muhammadiyah Surakarta; Jalan Ahmad Yani Tromol Pos 1 Pabelan Surakarta 57162 Indonesia
2. Chemical Engineering Department; University of Waterloo; 200 University Avenue West, Waterloo ON, Canada N2L 3G1
3. Department of Chemical Engineering; The Petroleum Institute; 2533 Abu Dhabi United Arab Emirates