1. Faculty of Engineering and the Built Environment, University of Johannesburg, P. O. Box 534, Auckland Park, South Africa
2. Department of Metallurgical and Materials Engineering, University of Nigeria, Nsukka Postal Code 410001, Nigeria
3. Africa Centre of Excellence, ACESPED University of Nigeria, Nsukka Postal Code 410001, Nigeria
4. Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka Postal Code 410001, Nigeria