close-spaced rotary beam aerial

  • 1tunnels and underground excavations — ▪ engineering Introduction        Great tunnels of the world Great tunnels of the worldhorizontal underground passageway produced by excavation or occasionally by nature s action in dissolving a soluble rock, such as limestone. A vertical opening …

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  • 2motion-picture technology — Introduction       the means for the production and showing of motion pictures. It includes not only the motion picture camera and projector but also such technologies as those involved in recording sound, in editing both picture and sound, in… …

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  • 3coal mining — Coal was very important in the economic development of Britain. It was used as fuel in the factories built during the Industrial Revolution and continued to be important until the 1980s. The main coalfields are in north east England, the north… …

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  • 4Glossary of military abbreviations — List of terms, acronyms, information, related to modern armour, artillery, infantry, weapons, and related military subject matter.* AA anti aircraft * AAA anti aircraft artillery Triple A * AAAV Advanced Amphibious Assault Vehicle * AAD Armoured… …

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  • 5Earth exploration — Introduction   the investigation of the surface of the Earth and of its interior.  By the beginning of the 20th century most of the Earth s surface had been explored, at least superficially, except for the Arctic and Antarctic regions. Today the… …

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