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Eng ID Term Definition
3861
picture plane
A plane upon which a system of lines or RAYS from an object to form an IMAGE or picture can be projected. In perspective drawing, the system... more
A plane upon which a system of lines or RAYS from an object to form an IMAGE or picture can be projected. In perspective drawing, the system of RAYS is understood to converge to a single point. In PHOTO­GRAMMETRY, the PHOTOGRAPH is the picture plane.
3862
piedmont
(adj.). Situated or formed at the base of MOUNTAINS.
3863
pie graph
Circular SYMBOL divided into sectors to indicate proportions of a total value.
3864
pier
A long, narrow structure extending into the water to afford a berthing place for vessels, to serve as a promenade, etc. See also JETTY.
3865
pierhead
The outer end of a PIER. Also called wharf­head.
3866
piezoelectric effect
The PHENOMENON, exhibited by certain crystals, in which mechanical compression produces a potential dif­ference between opposite cry­stal fa... more
The PHENOMENON, exhibited by certain crystals, in which mechanical compression produces a potential dif­ference between opposite cry­stal faces, or, an applied electric field produces corresponding changes in dimensions.
3867
piezoelectricity
The property exhibited by some asym­metrical crystalline materials which when sub­jected to strain in suitable directions develop elec­tric ... more
The property exhibited by some asym­metrical crystalline materials which when sub­jected to strain in suitable directions develop elec­tric POLARI­ZATION proportional to the strain. Inverse piezo­elec­tricity is the effect in which mechanical strain is produced in certain asym­metrical crystalline mater­ials when subjected to an external electric field; the strain is proportional to the electric field.
3868
piggot gun
A coring instrument for obtaining deep-sea BOTTOM SAMPLES. This instrument uses an explosive charge to drive a metal bit into the BOTTOM at ... more
A coring instrument for obtaining deep-sea BOTTOM SAMPLES. This instrument uses an explosive charge to drive a metal bit into the BOTTOM at the instant the sharp end of the bit strikes the BOTTOM.
3869
pigmentation
A colouring of tissue by deposition of PIGMENTS.
3870
pigments
A colouring matter used as paint or dye or a natural colouring matter of a tissue.
3871
pile
A long heavy timber or section of steel, wood, concrete, etc., forced into the earth or SEAFLOOR to serve as a support, as for a PIER, or t... more
A long heavy timber or section of steel, wood, concrete, etc., forced into the earth or SEAFLOOR to serve as a support, as for a PIER, or to resist lateral pressure; or as a free standing pole within a marine environment.
3872
piling
A group of piles set in a row.
3873
pillar buoy
A BUOY composed of a tall central struc­ture on a broad flat base.
3874
pilot
1. A person who directs the movements of a vessel through pilot waters, usually a person who has demonstrated extensive knowledge of channel... more
1. A person who directs the movements of a vessel through pilot waters, usually a person who has demonstrated extensive knowledge of channels, aids to navigation, dangers to navigation, etc., in a particu­lar area and is licensed for that area. 2. A book of sailing directions.
3875
pilot chart
See CHART.
3876
pilot station
The office or headquarters of pilots; the place where the services of a pilot may be obtai­ned.
3877
pilot waters
Areas in which the services of a marine pilot are available. Waters in which NAVIGATION is by piloting. More usually called pilotage waters ... more
Areas in which the services of a marine pilot are available. Waters in which NAVIGATION is by piloting. More usually called pilotage waters in British terminology.
3878
pilotage waters
See PILOT WATERS.
3879
ping
An acoustic pulse signal projected by an under­water TRANSDUCER.
3880
pinger
A battery powered acoustic device equipped with a TRANSDUCER that transmits SOUND WAVES. When the pinger is attached to a wire and lowered i... more
A battery powered acoustic device equipped with a TRANSDUCER that transmits SOUND WAVES. When the pinger is attached to a wire and lowered into the water, the direct and bottom reflected sound can be monitored with a listening device. The difference between the arrival time of the DIRECT and REFLECTED WAVES is used to compute the distance of the pinger from the ocean bottom.