| nail bed | The area of the corium on which the nail rests; it is extremely sensitive and presents numerous longitudinal ridges on its surface. According to some anatomists, the nail bed is the portion covered by the body of the nail, the nail matrix being only the part on which the root of the nail rests. Synonym: matrix unguis, keratogenous membrane, nail matrix, onychostroma. (05 Mar 2000) |
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| fluidised-bed boiler | A large, refractory-lined vessel with an air distribution member or plate in the bottom, a hot gas outlet in or near the top, and some provisions for introducing fuel. The fluidised bed is formed by blowing air up through a layer of inert particles (such as sand or limestone) at a rate that causes the particles to go into suspension and continuous motion. The super-hot bed material increased combustion efficiency by its direct dontact with the fuel. (05 Dec 1998) |
| fracture bed | A narrow, extra-firm bed for treatment of fractures; usually incorporates an overhead frame for traction apparatus. (05 Mar 2000) |