concentrate;+make+dense
51Europe, history of — Introduction history of European peoples and cultures from prehistoric times to the present. Europe is a more ambiguous term than most geographic expressions. Its etymology is doubtful, as is the physical extent of the area it designates.… …
52mineral deposit — Introduction aggregate of a mineral in an unusually high concentration. About half of the known chemical elements (chemical element) possess some metallic (metal) properties. The term metal, however, is reserved for those chemical… …
53tin processing — Introduction preparation of the ore for use in various products. Tin (Sn) is a relatively soft and ductile metal with a silvery white colour. It has a density of 7.29 grams per cubic centimetre, a low melting point of 231.88° C… …
54railroad — /rayl rohd /, n. 1. a permanent road laid with rails, commonly in one or more pairs of continuous lines forming a track or tracks, on which locomotives and cars are run for the transportation of passengers, freight, and mail. 2. an entire system… …
55Life Sciences — ▪ 2009 Introduction Zoology In 2008 several zoological studies provided new insights into how species life history traits (such as the timing of reproduction or the length of life of adult individuals) are derived in part as responses to… …
56Nobel Prizes — ▪ 2009 Introduction Prize for Peace The 2008 Nobel Prize for Peace was awarded to Martti Ahtisaari, former president (1994–2000) of Finland, for his work over more than 30 years in settling international disputes, many involving ethnic,… …
57Heliciculture — (snail farming) is the process of farming or raising snails.HistoryRoasted snail shells have been found in archaeological excavations, an indication that snails have been eaten since prehistoric times [ [http://watarts.uwaterloo.ca/… …
58meteorite — meteoritic /mee tee euh rit ik/, meteoritical, meteorital /mee tee euh ruyt l/, adj. /mee tee euh ruyt /, n. 1. a mass of stone or metal that has reached the earth from outer space; a fallen meteoroid. 2. a meteoroid. [1815 25; METEOR + ITE1] * * …
59World War II — the war between the Axis and the Allies, beginning on September 1, 1939, with the German invasion of Poland and ending with the surrender of Germany on May 8, 1945, and of Japan on August 14, 1945. Abbr.: WWII * * * or Second World War (1939–45)… …
60petroleum production — Introduction recovery of crude oil and, often, associated natural gas from the Earth. petroleum is a naturally occurring hydrocarbon material that is believed to have formed in deep sedimentary (sedimentary rock) beds from animal and …
