A new type of transparent armor made of aluminum could one day replace glass in military vehicles. The product is called aluminum oxynitride. It is being tested by the Army and the University of Dayton Research Institute in Ohio. The material is a ceramic compound with a high compressive strength and durability, according to an Army statement issued this week. It performs better than the multilayered glass products currently in use, and its about half the weight. It is virtually scratch-resistant. "The substance itself is light-years ahead of glass," said 1st Lt. Joseph La Monica, who heads the research. Glass...