الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
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Abstract
Special thanks go to my supervisors Pear. Mohamed Matonoud El Sherbioy Professor of Electronics Department of Material Science Institute Of Graduate Studies and Research University of Alexandria & Dr. Mostar’ %Mut Dares —F.nen, Department of Hotels Faculty of Tourism and Hotels University of Alexandria for their support .enswragement and valuable comments they made upon reading the draft of this thesis Special thanks too go to ty prothsot Prof. Dr. Enat Mgt EL Tanis Kona y for his support &encouragement: also I deeply thank m■ brother essz mr for helping me especially in the technical issues. My most sincere graduate goes to my family for their encouragemenj. tolerance and for forbearance during the course of my study.