1. Professor, King Fahd Univ. of Petroleum and Minerals, Dhahran 31261, Saudi Arabia (corresponding author).
2. Ph.D. Student, King Fahd Univ. of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
3. Professor, King Fahd Univ. of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.