1. Department of Mathematics, Sciences and Physical Education, College of Education, University of Rwanda, Kigali 250, Rwanda
2. Department of Chemistry, College of Sciences and Technology, University of Rwanda, Kigali 250, Rwanda
3. Department of Mechanical Engineering, Faculty of Engineering and Built Environment, Tamale Technical University, Tamale GA184, Ghana
4. Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China