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gun control

(Encyclopedia)gun control, government limitation of the purchase and ownership of firearms. The availability of guns is controlled by nations and localities throughout the world. In the United States the “right o...

control surface

(Encyclopedia)control surface: see airfoil.

numerical control

(Encyclopedia)numerical control: see computer-aided manufacturing. ...

air mass

(Encyclopedia)air mass, large body of air within the earth's atmosphere in which temperature and humidity, although varying at different heights, remain similar throughout the body at any one height. Air masses for...

air conditioning

(Encyclopedia)CE5 Cross section of air conditioning unit. air conditioning, mechanical process for controlling the humidity, temperature, cleanliness, and circulation of air in buildings and rooms. Indoor air i...

plein-air

(Encyclopedia)plein-air plān-ârˈ, Fr. plĕn-ĕrˈ [key] [Fr.,=open-air], term used for paintings or drawings made directly from nature and infused with a feeling of the open air. Painting outdoors is a relativel...

compressed air

(Encyclopedia)compressed air, air whose volume has been decreased by the application of pressure. Air is compressed by various devices, including the simple hand pump and the reciprocating, rotary, centrifugal, and...

air lock

(Encyclopedia)air lock, compartment connecting two different environments, usually at different pressures, that enables personnel to transfer from one environment to the other. Space capsules have air locks to enab...

liquid air

(Encyclopedia)liquid air, ordinary air that has been liquefied by compression and cooling to extremely low temperatures (see liquefaction). Its commercial preparation involves purification by washing to remove solu...

lock, air

(Encyclopedia)lock, air: see air lock.