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degree-day

(Encyclopedia)degree-day, a unit of measure used to estimate the fuel and power requirements in heating and cooling a building; it is equal to a difference of 1 degree between the outdoor daily average temperature ...

element

(Encyclopedia)CE5 element, in chemistry, a substance that cannot be decomposed into simpler substances by chemical means. A substance such as a compound can be decomposed into its constituent elements by means o...

coral

(Encyclopedia)coral, small, sedentary marine animal, related to the sea anemone but characterized by a skeleton of horny or calcareous material. The skeleton itself is also called coral. Although most corals form c...

gadolinium

(Encyclopedia)gadolinium gădəlĭnˈēəm [key], metallic chemical element; symbol Gd; at. no. 64; at. wt. 157.25; m.p. 1,312℃; b.p. 3,233℃; sp. gr. 7.898 at 25℃; valence +3. Gadolinium is a malleable, ducti...

toxic waste

(Encyclopedia)toxic waste is waste material, often in chemical form, that can cause death or injury to living creatures. It usually is the product of industry or commerce, but comes also from residential use, agric...

vortex

(Encyclopedia)vortex vôrˈtĕks [key], mass of fluid in whirling or rotary motion. To simplify the analysis, vortex motion usually describes motions in a frictionless fluid. In such cases the absence of friction w...

fats and oils

(Encyclopedia)fats and oils, group of organic substances that form an important part of the diet and also are useful in many industries. The fats are usually solid, the oils generally liquid at ordinary room temper...

haze

(Encyclopedia)haze, suspension in the atmosphere of minute dust or salt particles that are not individually seen but that nevertheless reduce visibility. So-called damp haze and dry haze produce different optical e...

Air Force, United States Department of the

(Encyclopedia)Air Force, United States Department of the, military department within the U.S. Dept. of Defense (see Defense, United States Department of). The Air Force traces its roots to the founding of the Aeron...

hydrogen

(Encyclopedia)hydrogen hīˈdrəjən [key] [Gr.,=water forming], gaseous chemical element; symbol H; at. no. 1; interval in which at. wt. ranges 1.00784–1.00811; m.p. −259.14℃; b.p. −252.87℃; density 0.08...