AIR QUALITY |
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Air quality generally refers to either the outdoor and indoor air quality standards set by the US Government that determines the acceptable levels of certain gaseous emissions.
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COOLING TOWERS |
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Cooling towers are structures for cooling water or other working medium to near-ambient temperature. The primary use of large, industrial cooling towers is to lower the temperature of the cooling water used in power plants, petroleum refineries, petrochemical plants, natural gas processing plants and other industrial facilities. It is desirable to cool the water rather than simply discharging it because the cooling water is typically demineralized and it is cheaper to cool it rather than getting more demineralized water. Furthermore, discharging large amounts of hot water may raise the temperature of the receiving river or lake to an unacceptable level for the local ecosystem. A cooling tower serves to dissipate the heat into the atmosphere instead and wind and air diffusion spreads the heat over a much larger area than hot water can distribute heat in a body of water.
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DEEP SEA DIVER |
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Diving is still evolving, but general classifications have grown up to describe various diving activities. These classifications include but are not limited to:
Commercial diving
Military diving
Combat divers
Armed forces work divers
Recreational diving
Underwater Photography & Video
Spear fishing
Marine life counting and identification
Rescue & recovery diving
Scientific diving
Technical diving (also called Tech Divers)
Cave diving
Cavern diving
Deep diving
Ice diving
Wreck diving
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PROFESSIONAL SCUBA DIVER |
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Diving is still evolving, but general classifications have grown up to describe various diving activities. These classifications include but are not limited to:
Commercial diving
Military diving
Combat divers
Armed forces work divers
Recreational diving
Underwater Photography & Video
Spear fishing
Marine life counting and identification
Rescue & recovery diving
Scientific diving
Technical diving (also called Tech Divers)
Cave diving
Cavern diving
Deep diving
Ice diving
Wreck diving
Scuba diving is swimming underwater while using self-contained breathing equipment.
Scuba divers exploring fish and coral.By carrying a source of compressed air, the scuba diver is able to stay underwater longer than with the simple breath-holding techniques used in Snorkeling and Free-diving, and is not hindered by air-lines to a remote air source. The scuba diver typically swims underwater by using fins attached to the feet. However, some divers also move around with the assistance of a DPV (Diver Propulsion Vehicle), commonly referred to as a "scooter", or by using surface-tethered devices called sleds, which are pulled by a boat.
The term SCUBA arose during World War II and originally referred to USA combat frogmen's oxygen rebreathers, developed by Dr. Christian Lambertsen for underwater warfare. Today, SCUBA typically usually refers to the in-line open-circuit equipment, developed by Emile Gagnan and Jacques-Yves Cousteau, in which compressed gas (usually air) is inhaled from a tank and then exhaled into the water. However, rebreathers (both semi-closed circuit and closed circuit) are also self-contained systems (as opposed to surface-supplied systems) and are therefore classified as SCUBA.
Although the word 'SCUBA' is an acronym for "Self Contained Underwater Breathing Apparatus", it has also become acceptable to refer to SCUBA as 'scuba equipment' or 'scuba apparatus'.
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REFRIGERATION SYSTEMS |
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Refrigeration (from the Latin frigus, frost) is generally the cooling of a body by the transfer of a portion of its heat away from it. Applications include conservation, especially of food, and lowering the temperature of drinks to one that is more agreeable for consumption. Domestic refrigerators are common in kitchens, with separate sections or separate machines for cooling and freezing.
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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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