Masonry oven India, tandoors are traditional clay ovens, although these days modern electrically fired tandoors are available. The open-topped tandoor is a transitional design between the earth oven and the Roman-plan masonry oven. In the precolumbian Americas, similar ovens were often made of clay or adobe and are now referred to by the Spanish term "horno" (meaning "oven"). Horns are also traditional in the American Southwest. The traditional direct-fired masonry design is often called a "Roman" or "black" oven and dates in Western culture to at least the Roman Republic. It is known as a black oven because the fire generates soot
Ceramic armor These are the motivations for new types of armor plate. These new designs use two and three dimensional arrays of ceramic elements that can be rigid, flexible or semi-flexible. Dragon Skin body armor is one these systems, although it has failed numerous tests performed by the US Army, and has been rejected. European developments in spherical and hexagonal arrays have resulted in products that have some flex and multi-hit performance. The manufacture of array type systems with flex, consistent ballistic performance at edges of ceramic elements is an active area of research. In addition advanced ceramic processing techniques arrays require