Abstract: An apparatus and method for heating water using a microwave powered boiler. The apparatus consists of a three cabinet arrangement which permits the dry incorporation of wave guides and the tunneling of microwave energy completely around and into a seamless water chamber. The apparatus can be adapted to provide a hydronic heating system, a forced hot air heating system, a tankless domestic hot water supply and a hot water heater.

Abstract: The invention provides a hard, strong ceramic body and a ceramic raw batch and method for manufacture whereby the body, after being formed of the raw batch in the shape and size desired, can then be fired to monolithic structure without any shrinkage or distortion during the firing operation. The raw batch contains aluminum oxide, magnesium oxide, glass frit and a silicone resin, these constituents being present in a ratio such that after the firing operation the resulting monolithic body contains from about 70% to 95% by weight crystalline material and the remainder interstitial glass, the crystalline material consisting predominantly of magnesium aluminate spinel and alumina. The ceramic and method have particular utility for making dental crowns and other dental appliances where a precise fit along with high strength and wear resistance are desirable.