of fuels with inorganic contaminants. Fuel cenospheres are always black. The refractory cenosphere as defined above is synonymous with microballoons or glass microspheres and excludes the traditional fuel cenospheres definition. The use of the term cenosphere in place of microballoons is widespread, and it has become an additional definition. Applications Syntactic foam Cores of sandwich structure Removal of nitrogen oxides Dry reforming of methane See also References Ceramic materials Particulates Pollutants Refractory materials