Page:Glossary of NPIC Terminology (1965).pdf/7

Rh dispersion -- The separation of a single ray of white light into a group of colored rays by a prism or other optical means. dock -- Water area between 2 piers. A pier is sometimes erroneously called a dock. dolphin -- Usually consists of a cluster of piles fastened together at the top and used for protecting other structures and for mooring or warping a vessel. Dolphins may be in the water, on the beach, or, infrequently, on a wharf. double-base propellant -- A propellant made of nitrocellulose granules bound together with a gelatinous binder of nitroglycerine. duplicate positive -- See. earth banked -- To have earth piled against the sides. earth covered -- To be covered completely with earth (except, for example, the entrances of an earth—covered building may be exposed); earth covered and earth mounded are nearly synonymous; however, the term earth mounded implies that the earth has been piled in a heap that obscures the configuration of the covered object, and the term earth covered usually implies a thinner covering. (In some instances a structure built in an excavation and then covered with a deep layer of earth may more aptly be described as being underground rather than earth covered or mounded.) earth mounded -- To be covered with a heap of earth, e.g., an earth-mounded storage bunker, the fabrication building is earth mounded, the building is mounded with earth. See. effective damage -- That damage necessary to render a target element inoperative, unserviceable, nonproductive, or uninhabitable. (damage assessment) electromagnetic radiation -- See. electromagnetic spectrum -- The total frequency range of electromagnetic radiation. See. emissivity -- The ratio of radiation emitted by a surface to the radiation emitted by a "black body" at the same temperature and under the same conditions. This may be expressed for the total radiation from all wavelengths or for restricted bands of wavelengths. Targets are described in relation to their apparent emissivity. The following categories are generalized target descriptions (assuming a target and its background have the same emissivity factor): a) warm target -- A target that is warmer than its background will image lighter than its background on the film. b) hot target -- A target that is much warmer than its background will image much brighter than its background. 0) cool target -- A target that is cooler than its background will image darker than its background. d) cold target -- A target that is much colder than its background will image much darker than its background. (infrared) exposure -- The function of the duration of time and the intensity of illumination upon photographic material. extent of damage -- The visible plan area of damage to a target element, usually expressed in units of 1,000 square feet in detailed damage analysis and in approximate percentages in immediate-type damage assessment reports (e.g., 50percent structural damage). (damage assessment) fair interpretability --See. fiducial mark -- A standard geometrical reference point imaged at the margin of a photograph. The intersection of the primary