Masonry oven more common as accessory features of a masonry heater. A compromise design known as the gueulard in France combines aspects of both internal and external-fired models. Masonry ovens remain popular in part because of the way their use affects cooking processes and food flavor. Where modern gas or electric ovens cook food by moving hot air around inside an insulated, lightweight box, a masonry oven works by soaking up heat, like a battery building up a full charge. When hot, the heavy oven walls release the heat slowly, for hours. Thus the food is cooked not only by hot air,
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