Masonry oven these primitive-looking ovens were still being produced in Barnstaple potteries as late as 1890". A cloche or cooking bell is like an upside-down, fired ceramic bowl with a handle on top. It is heated in the fire along with a flat rock or open spot on the hearth. The prepared dough is placed on the hot rock or hearth floor, and then covered with the cloche, and perhaps hot coals or ashes for additional heat. The method goes back to ancient Egypt and Greece, and was probably the first form of masonry oven. It is possible to get some of
Ceramic membrane gas separation. Examples are the separation of oxygen from air, or the separation of hydrogen gas from a mixture. Porous ceramic membranes are chiefly used for gas separation and micro- or nanofiltration. They can be made from both crystalline as well as amorphous solids. An example of an amorphous membrane is the silica membrane. An example of a highly porous membrane is the type made of silicon carbide. The first ceramic membranes were produced in France in the 1980s for the purpose of uranium enrichment in the nuclear industry. After many of the nuclear plants were set up in France