1. Universiti Teknologi Malaysia,School of Mechanical Engineering,Johor Bahru,Johor,Malaysia,81310 UTM
2. Sudan University of Science and Technology,Department of aeronautical Engineering,Khartoum,Sudan
3. University of Khartoum,Department of Mechanical Engineering,Khartoum,Sudan
4. Al Baha University Sudan university of sciences and Technology,Mechanical engineering dept.,Khartoum,Sudan