drop

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drop

1. a steep or sheer incline or slope
2. Military the act of unloading troops, equipment, or supplies by parachute
3. Theatre See drop curtain
4. Nautical the midships height of a sail bent to a fixed yard
5. Austral Cricket slang a fall of the wicket
6. See drop shot
7. Rugby short for drop kick, drop-kick See also drop off dropout

Drop

Any one of the guttae attached to the underside of the mutules or triglyphs of a Doric entablature.

Drop

 

a small volume of liquid that is bounded in a state of equilibrium by a surface of rotation.

Drops form when a liquid flows slowly out of a small opening or runs off the edge of a surface, as well as when a liquid is atomized or emulsified. Drops also form when vapors condense on solid nonwettable surfaces and on condensation nuclei (ions, dust particles) in gaseous media; water droplets in the atmosphere arise in this way in the formation of dew, fog, and clouds.

The form of a drop is determined by the effect of surface tension (tending to decrease the surface of the drop) and external forces (above all, gravity). Microscopic drops for which gravity is not a decisive factor, and drops under the conditions of weightlessness have the form of a sphere, which is a body with minimum surface for a given volume. Large drops under earth conditions take a spherical form only when the densities of the drop and of the surrounding medium are equal. Falling raindrops, affected by gravity, the pressure of the opposing air current, and surface tension, assume the shape of a bun (broader across than vertically). Drops assume the shape of a flattened sphere on nonwettable surfaces, and they spread out on wettable surfaces.

The form and size of drops breaking away from the end of a capillary tube (pipette) depend on the diameter of the tube, the surface tension o~, and the density of the liquid. This relationship forms the basis for the determination of the surface tension of liquids from the weight of the drops leaving a vertical cylindrical tube (stalagmometer) and from the shape of the drops suspended from the end of a tube or resting on a flat surface.

IU. N. DROZHZHIN

drop

[dräp]
(fluid mechanics)
The quantity of liquid that coalesces into a single globule; sizes vary according to physical conditions and the properties of the fluid itself.
(hydrology)
The difference in water-surface elevations that is measured up-and downstream from a narrowing in the stream.
(metallurgy)
A casting defect due to the falling of a portion of sand from an overhanging section of the mold.
(mineralogy)
A funnel-shaped downward intrusion of sedimentary rock into the roof of a coal seam.
(plant pathology)
A fungus disease of various vegetables caused by Sclerotinia sclerotiorum and characterized by wilt and stem rot.

drop

1. Any one of the guttae under the mutules or triglyphs of a Doric entablature.
2. In a cabinet lock, the vertical dimension from the finished edge of the lock to the center of the cylinder or tube.
3. In air conditioning, the vertical distance that a horizontally projected airstream falls from its original elevation when leaving an outlet, measured at the end of the throw.
4. Same as drop curtain.
5. Same as drop panel.
6. Of a stair, a fitting used to close the bottom end of a tubular newel.
7. Same as pendant, 2; also see corner drop.
8. Same as turned drop.
References in periodicals archive ?
Since the Department of Health considers bird droppings to be hazardous waste, Mr.
Cleaning up bird droppings is a very dangerous business and must be handled with precision and care," said Phil Waldorf, president of Bell Environmental Services who has also written a book about the subject entitled, Health Hazards From Pigeons, Starlings and English Sparrows.
Bell Environmental Services has recently taken great pains to alert the public to the dangers of bird droppings.
According to the book and website, by preventing birds from landing on buildings, disease-causing organisms commonly found in bird droppings can be stopped from spreading to the building's occupants.
This is from bird droppings accumulating in or near the HVAC systems and spreading the disease causing organisms commonly found in the bird fecal matter to every occupant," said Phil Waldorf, president of Bell Environmental Services.
The first pages in of the book features graphic and current photographs of rooftops (where most ventilation systems are kept) of prominent office and residential buildings literally buried under four to five feet of bird droppings.
More than sixty diseases are associated with bird droppings.
Bird droppings are considered to be hazardous waste and special bio-suits and filter masks are for those charged with the removal of bird waste.