1. Petra International Conference on Mathematics, Oct. 23-25 Oct., 2007. Al-Hussein Bin Talal University/ Jordan. October/ 23-25 /2007. 2. Dalhousie University Halifax Conference, Nova Scotia, Canada, The strength of rigid/plastic composites: a comparison of piecewise-linear and power-law approximations, July/17/2006 3. Arabic Council for Training Arab Students. Al-Hussein Bin Talal University/ Jordan. August 9/2007 .