concrete bed
81environment — environmental, adj. environmentally, adv. /en vuy reuhn meuhnt, vuy euhrn /, n. 1. the aggregate of surrounding things, conditions, or influences; surroundings; milieu. 2. Ecol. the air, water, minerals, organisms, and all other external factors… …
82Mexico City — a city in and the capital of Mexico, in the central part. 8,906,000; ab. 7400 ft. (2255 m) above sea level. Official name, México, Distrito Federal /me hee kaw dees tree taw fe dhe rddahl /. * * * Spanish Ciudad de México City (pop., 2000: city,… …
83Dam — This article is about structures for water impoundment. For other uses, see Dam (disambiguation). Hoover Dam, a concrete arch gravity dam in Black Canyon of the Colorado River. Lake Mead in the background is impounded by the dam …
84Burdekin Bridge — The Burdekin Bridge (known as the Silver Link) spans the Burdekin River between the towns of Ayr, Queensland and Home Hill, Queensland. The Bridge was completed in 1957. Construction began 10 years earlier in 1948. 1097 metres (3,600 ft) in… …
85Cement kiln — Cement kilns are used for the pyroprocessing stage of manufacture of Portland and other types of hydraulic cement, in which calcium carbonate reacts with silica bearing minerals to form a mixture of calcium silicates. Over a billion tonnes of… …
86cement — cementable, adj. cementer, n. cementless, adj. /si ment /, n. 1. any of various calcined mixtures of clay and limestone, usually mixed with water and sand, gravel, etc., to form concrete, that are used as a building material. 2. any of various… …
87Engineering Projects — ▪ 1995 Introduction BRIDGES Notable Engineering Projects(For Notable Engineering Projects in work, see Table (Notable Engineering Projects).) As the decade of the 1990s reached its midpoint, the limits to bridge design were being… …
88roads and highways — ▪ transportation Introduction traveled way on which people, animals, or wheeled vehicles move. In modern usage the term road describes a rural, lesser traveled way, while the word street denotes an urban roadway. Highway refers to a major… …
89Benjamin Tucker — Infobox Writer name = Benjamin Tucker |thumb|right|Benjamin Ricketson Tucker imagesize = caption = pseudonym = birthname = birthdate = April 17, 1854 birthplace = deathdate = June 22, 1939 deathplace = Monaco occupation = writer nationality =… …
90Radioactive waste — 2007 ISO radioactivity danger logo, designed in part for long term radioactive waste depositories which might survive into a far future time in which all knowledge of the meaning of present common radiation danger symbols and signs has been lost… …
