Dr. Mohamed Hussein Faris , Ph.d in mechanical engineering and is the founder of the famous used Total down time importance (TDTI) method and techniques for failures ranking of operating equipment. He had published several articles and topics in engineering and maintenance management. Also, Dr. Faris is the book's author of "The Integrated Maintenance-the way to new maintenance techniques).He has a long valuable experience in maintenance engineering and management with rich background in modern industrial fields. https://scholar.google.com/citations?hl=en&user=DI-jwP8AAAAJ