| radiant heat | Heat given off from any body in the form of waves, similar to light waves but of greater wavelength. (05 Mar 2000) |
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| radiant | 1. Emitting or proceeding as from a center; rays; radiating; radiate. 2. Especially, emitting or darting rays of light or heat; issuing in beams or rays; beaming with brightness; emitting a vivid light or splendor; as, the radiant sun. "Mark what radiant state she spreads." (Milton) 3. Beaming with vivacity and happiness; as, a radiant face. 4. Giving off rays; said of a bearing; as, the sun radiant; a crown radiant. 5. <botany> Having a raylike appearance, as the large marginal flowers of certain umbelliferous plants; said also of the cluster which has such marginal flowers. <physics> Radiant energy See Radiant. Origin: L. Radians, -antis, p. Pr. Of radiare to emit rays or beams, fr. Radius ray: cf. F. Radiant. See Radius, Ray a divergent line. 1. <optics> The luminous point or object from which light emanates; also, a body radiating light brightly. 2. <geometry> A straight line proceeding from a given point, or fixed pole, about which it is conceived to revolve. 3. <astronomy> The point in the heavens at which the apparent paths of shooting stars meet, when traced backward, or whence they appear to radiate. Source: Websters Dictionary (01 Mar 1998) |
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| radiant energy | Energy contained in light rays or any other form of radiation. (05 Mar 2000) |
| radiant intensity | The luminous flux per unit solid angle in a given direction. Synonym: candle-power, radiant intensity. (05 Mar 2000) |
| atomic heat | The amount of heat required to raise an atom from 0 |
| molar heat capacity | <chemistry> The amount of energy required to raise the temperature of one mole of a substance by one degree Celsius (or Kelvin). (09 Jan 1998) |
| molecular heat | The product of the specific heat of a body multiplied by its molecular weight. (05 Mar 2000) |
| combined heat and power | An older term for what is now generally called cogeneration. The term is currently used in Europe and other foreign countries. (05 Dec 1998) |
| conductive heat | Heat transmitted by direct contact, as by an electric pad or hot water bottle. (05 Mar 2000) |
| convective heat | Heat conveyed by a warm medium, such as air or water, in motion from its source. (05 Mar 2000) |
| conversive heat | Heat produced in a body by the absorption of waves that are not in themselves hot, such as the sun's rays or infrared radiation. (05 Mar 2000) |
| prickly heat | An eruption of papules and vesicles at the orifices of sweat glands, accompanied by redness and inflammatory reaction of the skin. Synonym: heat rash, lichen infantum, lichen strophulosus, prickly heat, strophulus, summer rash, tropical lichen, lichen tropicus, wildfire rash. (05 Mar 2000) |
| heat | <chemistry> Energy transferred between two objects because of a temperature difference, the thermal motion of atoms and molecules. For chemical systems the sign for heat flow into the system is positive, because this process increases the internal energy of the system. Heat flowing out of the system is defined to be negative, since this process decreases the internal energy of the system. (09 Jan 1998) |
| heat apoplexy | A severe and often fatal illness produced by exposure to excessively high temperatures, especially when accompanied by marked exertion. It can manifest by elevated body temperature, lack of sweating, hot dry skin, and neurologic symptoms; unconsciousness, paralysis, headache, vertigo, confusion. In severe cases very high fever, vascular collapse, and coma develop. Synonym: heat apoplexy, heat hyperpyrexia, malignant hyperpyrexia, thermic fever. (05 Mar 2000) |
| heat capacity | <chemistry> The amount of energy required to raise the temperature of an object by one degree Celsius (or Kelvin), it is represented by the symbol C and is given in units of J/K. (09 Jan 1998) |
| heat coagulation test | A test for measurement of protein in urine; albumin and globulin are coagulated by heat at an acid pH, and the amount of turbidity present provides a qualitative estimation of the degree of proteinuria. (05 Mar 2000) |