1. Department of Mechanical Engineering Science, University of Johannesburg, Corner Kingsway and University Road, Auckland Park, 2092, Johannesburg, South Africa
2. Department of Metallurgical Engineering, University of Johannesburg, Doornfontein, 2006, Johannesburg, South Africa
3. Department of Physics, University of Johannesburg, Corner Kingsway and University Road, Auckland Park, 2092, Johannesburg, South Africa