1. Department of Chemical Engineering, School of Chemical and Bio Engineering, Addis Ababa Institute of Technology, Addis Ababa University, Addis Ababa, Ethiopia
2. Department of Chemical Engineering, College Biological and Chemical Engineering, Addis Ababa Science and Technology University, P. O. Box 16417, Addis Ababa, Ethiopia
3. Center for Materials Engineering, Addis Ababa Institute of Technology, School of Multi-disciplinary Engineering, Addis Ababa, 1000, Ethiopia
4. Department of Physics, College of Natural and Social Science, Addis Ababa Science and Technology University, P. O. Box 16417, Addis Ababa, Ethiopia