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flywheel

(Encyclopedia)flywheel, heavy metal wheel attached to a drive shaft, having most of its weight concentrated at the circumference. Such a wheel resists changes in speed and helps steady the rotation of the shaft whe...

Boltwood, Bertram Borden

(Encyclopedia)Boltwood, Bertram Borden, 1870–1927, American chemist and physicist, b. Amherst, Mass., grad. Sheffield Scientific School, Yale, 1892. After graduate study at Leipzig and Yale (Ph.D., 1897), he taug...

Bridges, Simon Joseph

(Encyclopedia)Bridges, Simon Joseph, 1976–, New Zealand lawyer and politician, b. Auckland. A Maori and a member of the conservative National party, Bridges was a lawyer and prosecutor before he was first elected...

metabolism

(Encyclopedia)metabolism, sum of all biochemical processes involved in life. Two subcategories of metabolism are anabolism, the building up of complex organic molecules from simpler precursors, and catabolism, the ...

gamma radiation

(Encyclopedia)gamma radiation, high-energy photons emitted as one of the three types of radiation resulting from natural radioactivity. It is the most energetic form of electromagnetic radiation, with a very short ...

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 ...

fatigue, in physiology

(Encyclopedia)fatigue, in physiology, inability to perform reasonable and necessary physical or mental activity. Muscle fatigue, for example, results when the contractile properties of muscle are reduced, and conti...

nitric oxide

(Encyclopedia)nitric oxide or nitrogen monoxide, a colorless gas formed by the combustion of nitrogen and oxygen as given by the reaction: energy + N2 + O2 → 2NO; m.p. −163.6℃; b.p. −151.8℃. Nitric oxide ...

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...

Montt, Pedro

(Encyclopedia)Montt, Pedro mōnt [key], 1848–1910, president of Chile (1906–10). Son of Manuel Montt, he held with distinction several government posts. He was a minister under José Balmaceda but later joined...