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lubrication

(Encyclopedia)lubrication, introduction of a substance between the contact surfaces of moving parts to reduce friction and to dissipate heat. A lubricant may be oil, grease, graphite, or any substance—gas, liquid...

soman

(Encyclopedia)soman, colorless liquid used as a nerve gas. It boils at 167℃, evolving an odorless vapor. It is rapidly absorbed through the skin; death may result within 15 min of exposure. In nonfatal concentrat...

low-temperature physics

(Encyclopedia)low-temperature physics, science concerned with the production and maintenance of temperatures much below normal, down to almost absolute zero, and with various phenomena that occur only at such tempe...

deliquescence

(Encyclopedia)deliquescence dĕlˌəkwĕsˈəns [key], conversion of a solid substance into a liquid as a result of absorption of water vapor from the air. Since impurities in a solid lower its melting point, the a...

bromine

(Encyclopedia)bromine brōˈmēn, –mĭn [key] [Gr.,=stench], volatile, liquid chemical element; symbol Br; at. no. 35; at. wt. 79.904; m.p. –7.2℃; b.p. 58.78℃; sp. gr. of liquid 3.12 at 20℃; density of va...

decompression sickness

(Encyclopedia)decompression sickness, physiological disorder caused by a rapid decrease in atmospheric pressure, resulting in the release of nitrogen bubbles into the body tissues. It is also known as caisson disea...

isobar

(Encyclopedia)isobar īˌsəbărˈĭk [key], line drawn on a weather map through points of equal atmospheric pressure. Isobars are used to define cyclones (low-pressure regions) and anticyclones (high-pressure regi...

leaven

(Encyclopedia)leaven lĕvˈən [key], agent used to raise bread or other flour foods. Physical leavens include water vapor, which is released as steam at high temperatures (as in popovers), and air, which is incorp...

tabun

(Encyclopedia)tabun täˈbən [key], liquid chemical compound used as a nerve gas. It boils at 240℃ with some decomposition. The liquid is colorless to brownish; its vapors have a fruity odor similar to that of b...

iodine

(Encyclopedia)iodine īˈədīn, –dĭn [key] [Gr.,=violet], nonmetallic chemical element; symbol I; at. no. 53; at. wt. 126.90447; m.p. 113.5℃; b.p. 184.35℃; sp. gr. 4.93 at 20℃; valence −1, +1, +3, +5, o...