| heat exhaustion | A form of heat illness that results when the victim is dehydrated (fluid depleted). Common symptoms include: fatigue, lightheadedness, nausea, vomiting, headache, rapid heartbeat and lowered blood pressure. (27 Sep 1997) |
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| heat hyperpyrexia | 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 illness | A general term which describes three forms of heat related injury: heat cramps, heat exhaustion and heatstroke. (27 Sep 1997) |
| heat instability test | A test for the presence of unstable haemoglobins; fresh red blood cells lysed in distilled water develop a precipitate within one hour at 50캜 if unstable haemoglobin is present. (05 Mar 2000) |
| heat-labile | Destroyed or altered by heat. (05 Mar 2000) |
| heat lamp | A lamp that emits infrared light and produces heat; used to apply topical heat to the skin. Synonym: thermolamp. (05 Mar 2000) |
| heat oedema | Oedema caused by excessively high external temperature. (05 Mar 2000) |
| heat of combustion | The quantity of heat liberated per gram-molecular weight when a substance undergoes complete oxidation. (05 Mar 2000) |
| heat of compression | Heat produced when a gas is compressed. (05 Mar 2000) |
| heat of crystallization | The quantity of heat liberated or absorbed per mol when a substance passes into the crystalline state. (05 Mar 2000) |
| heat of dissociation | The heat (expressed in calories or joules) expended in the dissociation of 1 mol of a substance into specified products. (05 Mar 2000) |
| heat of evaporation | The heat absorbed in the evaporation of water, sweat or other liquid; for water it amounts to 540 cal/g at 100캜. Synonym: heat of vaporization. (05 Mar 2000) |
| heat of formation | The heat (expressed in calories or joules) absorbed or liberated during the (hypothetical) reaction in which a mole of a compound is formed from the necessary elements, in elemental form. (05 Mar 2000) |
| heat of fusion | <chemistry> The enthalpy change that occurs to melt a solid at its melting point. (09 Jan 1998) |
| heat of hydration | <chemistry> The enthalpy change associated with placing gaseous molecules or ions in water. (09 Jan 1998) |