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Onsager, Lars

(Encyclopedia)Onsager, Lars, 1903–76, American physical chemist, b. Oslo, Ph.D. Yale, 1935. Onsager taught at Brown Univ. from 1928 to 1933 and was on the faculty at Yale from 1933 until his retirement in 1972. H...

spontaneous combustion

(Encyclopedia)spontaneous combustion, phenomenon in which a substance unexpectedly bursts into flame without apparent cause. In ordinary combustion, a substance is deliberately heated to its ignition point to make ...

infrared radiation

(Encyclopedia)infrared radiation, electromagnetic radiation having a wavelength in the range from c.75 × 10−6 cm to c.100,000 × 10−6 cm (0.000075–0.1 cm). Infrared rays thus occupy that part of the electrom...

Dewar flask

(Encyclopedia)Dewar flask [for Sir James Dewar], container after which the common thermos bottle is patterned. It consists of two flasks, one placed inside the other, with a vacuum between. The vacuum prevents the ...

hot spring

(Encyclopedia)hot spring, natural discharge of groundwater having an elevated temperature. Most hot springs result from the emergence of groundwater that has passed through or near recently formed, hot, igneous roc...

brazing

(Encyclopedia)brazing, method of joining metal parts using nonferrous filler metals with high melting points such as copper, silver, and aluminum alloys. Brazing differs from soldering (see solder) by using a highe...

Silver Springs

(Encyclopedia)Silver Springs, mineral spring, N central Fla., source of the Silver River. The limestone spring, one of the world's largest and most famous, has a basin 80 ft (24 m) deep and 300 ft (91 m) wide. The ...

rigor mortis

(Encyclopedia)rigor mortis rĭˈgər môrˈtĭs [key], rigidity of the body that occurs after death. The onset may vary from about 10 min to several hours or more after death, depending on the condition of the body...

zero

(Encyclopedia)zero, that number which, when added to any number, leaves the latter unchanged; its symbol is 0. The introduction of zero into the decimal system was the most significant achievement in the developmen...

rhythm, biological

(Encyclopedia)rhythm, biological, or biorhythm, cyclic pattern of physiological changes or changes in activity in living organisms, most often synchronized with daily, monthly, or annual cyclical changes in the env...