ceiling(redirected from Usury Ceilings)
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the overhead inside lining of a room; a group of structural elements forming a secondary covering that is suspended from the roof.
Ceilings’ may be smooth or have projecting ribs, coffers, or other sculptured details. Smooth ceilings may or may not cover beams. They are made from plaster, boards, or sheeting materials. Suspended ceilings are used mainly to provide better sound absorption and to increase the sound insulation of the roof. They also conceal ventilation ducts, heating pipes, and electrical wiring. Such ceilings are used as decorative elements in interior design.
In modern mass-scale housing construction, the smoothing of seams and painting constitute the principal method for finishing ceilings made of slabs and panels. In public buildings, ceilings are more and more often being faced with slab materials having good acoustic properties. Such materials include perforated aluminum panels and porous plasterboard with a sound-absorbent fiberglass layer. In a room whose ceiling serves as an element of interior design, more decorative painted or sculptured finishes are used.
Z. A. KAZBEK-KAZIEV
ii. The highest pressure altitude that can be reached by an aircraft, excepting a zoom climb. At this altitude, the aircraft rate of climb is zero. Also called absolute ceiling.