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 foam area. It has been used as stiff lightweight structural material, specifically for support of reflecting telescope mirrors. Ceramic foams are hardened ceramics with pockets of air or another gas trapped in pores throughout the body of the material. These materials can be fabricated as high as 94 to 96% air by volume with temperature resistances as high as 1700 °C. Because many ceramics are already oxides or other inert compounds, there is little danger of oxidation or reduction of the material. Previously, pores had been avoided in ceramic components due to their brittle properties. However, in practice ceramic foams have