canopy

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canopy

1. a rooflike covering over an altar, niche, etc.
2. a roofed structure serving as a sheltered passageway or area
3. the nylon or silk hemisphere that forms the supporting surface of a parachute
4. the transparent cover of an aircraft cockpit
5. the highest level of branches and foliage in a forest, formed by the crowns of the trees

Canopy

A decorative hood above a niche, pulpit, or stall; a covered area that extends from the wall of a building, protecting an enclosure.

Canopy

 

(protective arch), in mining, a structure that ensures safe stoping and separation of minerals from caved material. Canopies are classified according to design and function as protective shields, flexible canopies of the enclosing and partitioning types, and interlayer canopies.

The design of the protective shield and the techniques for mining thick, sharply sloping coal seams using such shields were proposed by the Soviet scientist N. A. Chinakal in 1935 and were used in the Kuznetsk Coal Basin (Kuzbas) in 1938. Sectional protective shields were widely used in the 1940’s and 1950’s. Protective shields make it possible to work the entire thickness of a seam at once. Elastic reinforced-concrete protective shields have the great strength necessary for working seams in excess of 7-10 m thick and can be used many times. The shield is made of reinforced-concrete beams or pipes; for beams longer than 6 m it is made in sections. It moves along the slope behind the advancing face by its own weight and the weight of the caved material when the pillars on which it rests along the periphery are undermined.

Flexible metal canopies were first used in the USSR in the late 1940’s for working thick seams in the Kuzbas. They were subsequently used as components in new systems for working coal seams. Beginning in the early 1960’s they were used for working metallic ore deposits. In the early 1970’s, metal canopies were replaced by polymeric types that provide greater strength and malleability, better suitability for erection, and resistance to corrosion. The flexible canopy is set on the installation level along the upper limit of the floor or subfloor to be worked and at the mediate roof.

Interlayer canopies are used as a stable support for the roof, and sometimes for a floor, when mineral deposits are mined by sluicing. They are made of a 0.3–0.6-m thick layer of rocks or minerals, and the bridging is made of concrete slabs, wood, or metal grids.

V. V. ZHUKOV

canopy

[′kan·ə·pē]
(aerospace engineering)
The umbrellalike part of a parachute which acts as its main supporting surface.
The overhead, transparent enclosure of an aircraft cockpit.
(forestry)
The uppermost branching and spreading layer of a forest.

canopy

1. A decorative hood above a niche, pulpit, choir stall, or the like.
2. A covered area which extends from the wall of a building, protecting an entrance or loading dock.
3. The collective term for the upper blanket of foliage on trees.

canopy

i. The transparent cover over the cockpit of an airplane—fixed, hinged, or sliding and sometimes jettisonable by power. It also protects the occupants from airstream. In pressurized aircraft, a canopy helps hold and maintain cockpit pressure.
ii. The umbrella-like fabric body of a parachute, which provides high air-drag when deployed. It is usually made of nylon and supports the parachutists or load during the descent. It is the main deployable body of a parachute.
References in periodicals archive ?
The statement added that the canopies and all structures on the causeway were insured, while reports said they were under a 30-year warranty.
Testing was done to determine how long it would take to expand and collapse the canopies and move them into and out of position on a 15 per cent grade.
Air Force may give it the nod later this year to make replacement canopies for 500 46-lb canopies for the T-38 type trainer jets, as well as canopies for the new F/A-22 jet.
We embarked on modifying this bacterial dosimeter system for use in small plant canopies.
The plane captain had asked the chief, using sign language, whether the boarding ladder was clear so he could close the canopies.
Her goal is to discover the many species, or kinds of living things, that make their homes in rain-forest canopies - before the forests disappear.
First in Australia, then in Panama, and now in western Massachusetts and southern Florida, she has honed an expertise studying canopies -- forest ecosystems typically out of reach and beyond view of most ground-bound scientists.
For the bus station, however, he moves into more unfamiliar territory, employing steel and polycarbonate in a contemporary reinterpretation of the heroic iron and glass canopies of the nineteenth century.
The goal of Forest canopies is to synthesize the state-of-the-science for canopy processes and the organisms that live in them.
Since tree canopies have heights, widths, and depths, measurements of canopies are measurements of volume.