DREDGING / RECLAMATION |
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Dredging is miscellaneous excavator-type work underwater, usually in shallow sea or fresh water.
A dredge is a device for scraping or sucking the seabed, used for dredging.
A dredger is a ship or boat equipped with a dredge.
American usage sometimes calls the ship or boat a dredge.
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LEAD |
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Lead is a chemical element in the periodic table that has the symbol Pb (L. plumbum) and atomic number 82. A soft, heavy, toxic and malleable poor metal, lead is bluish white when freshly cut but tarnishes to dull gray when exposed to air. Lead is used in building construction, lead-acid batteries, bullets and shot, and is part of solder, pewter, and fusible alloys. Lead has the highest atomic number of all stable elements. (But see the article on Bismuth, which has a half life so long it can be considered stable.)
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PHOTOGRAPHY |
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Photography is the process of making pictures by means of the action of light. It involves recording light patterns, as reflected from objects, onto a sensitive medium through a timed exposure. The process is done through mechanical, chemical or digital devices commonly known as cameras.
The word comes from the Greek words φως phos ("light"), and γραφις graphis ("stylus", "paintbrush") or γραφη graphê, together meaning "drawing with light" or "representation by means of lines" or "drawing." Traditionally, the product of photography has been called a photograph. The term photo is a convenient abbreviation. Many people also call them pictures. In digital photography, the term image has begun to replace photograph. This term is neither more nor less correct than photograph, either in film or digital photography. (The term image is traditional in geometric optics.)
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TELECOMMUNICATIONS |
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Telecommunications is the communication of information over a distance. The term is most used to refer to communication using some type of signalling, such as the aldis lamp or the transmission and reception of electromagnetic energy. This covers many media and technologies including radio, fiber optics, telegraphy, television, telephone, data communication and computer networking, although other types of signalling are also included (see Telecommunications History and especially Early Telecommunications).
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