Hamdy Doweidar Taki El-Din Doweidar (PhD, DSc) was an Egyptian condensed matter physicist whose research topics included inorganic glasses, glass-ceramics, bio-active glasses, and structure-property correlations. He developed the Doweidar Model[1] which is used to correlate density, thermal expansion coefficient, molar refraction, and refractive index with the concentration of structural units in numerous types of glass. Doweidar also obtained a patent with two researchers for the preparation of a biologically active glass ionomer cement as a dental filling, characterized by vital activity due to the presence of bioactive crystalline phases in the retina glass (such as apatite and fluoroapatite), which react with SBF simulating solution to precipitate layers of hydroxyapatite and hydroxyapatite. These represent the basic crystalline phases in the formation of bones and teeth.[2] He was a Professor Emeritus at the Mansoura University.[3]