Dielectric heating involves the heating of electrically insulating materials by dielectric loss. It is electrically conductive and thermally insulating. This oxide layer is electrically insulating and serves as the dielectric of the capacitor. Increasing the thickness of an insulating layer increases the thermal resistance. Atomically thin boron nitride is one of the strongest electrically insulating materials. Heat transfer through an insulating layer is analogous to electrical resistance. Insulated cables can be directly fastened to structures without insulating supports. Typically, lofts are insulated by strips of insulating material laid between rafters. Sadoway, uses molten alloys of magnesium and antimony separated by an electrically insulating molten salt. Leakage increases exponentially as the thickness of the insulating region decreases. Diminishing returns are achieved with each successive doubling of the insulating layer. Naturally, this technique is not applicable to electrically insulating powders. The cable is protected by an outer insulating jacket. For many years researchers suspected that glaciers exist under a layer of insulating rocks. A vehicle is fitted with two thin shells, separated by insulating material.