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plutonium

(Encyclopedia)plutonium plo͞otōˈnēəm [key], radioactive chemical element; symbol Pu; at. no. 94; mass no. of most stable isotope 244; m.p. 641℃; b.p. 3,232℃; sp. gr. 19.84 at 20℃; valence +3, +4, +5, or ...

Turin

(Encyclopedia)Turin to͝orˈĭn, tyo͝orˈ–, tyo͝orĭnˈ [key], Ital. Torino, city (1991 pop. 962,507), capital of Piedmont and of Turin prov., NW Italy, at the confluence of the Po and Dora Riparia rivers. It i...

ozone layer

(Encyclopedia)ozone layer or ozonosphere, region of the stratosphere containing relatively high concentrations of ozone, located at altitudes of 12–30 mi (19–48 km) above the earth's surface. Ozone in the ozone...

steel industry

(Encyclopedia)steel industry, the business of processing iron ore into steel, which in its simplest form is an iron-carbon alloy, and in some cases, turning that metal into partially finished products or recycling ...

Leipzig

(Encyclopedia)Leipzig līpˈtsĭkh [key], city (1994 pop. 490,850), Saxony, E central Germany, at the confluence of the Pleisse, White Elster, and Parthe rivers. Originally a Slavic settlement called Lipsk, Leipz...

herbicide

(Encyclopedia)herbicide hrˈbəsīdˌ [key], chemical compound that kills plants or inhibits their normal growth. A herbicide in a particular formulation and application can be described as selective or nonselectiv...

interstellar matter

(Encyclopedia)interstellar matter, matter in a galaxy between the stars, known also as the interstellar medium. The interstellar gas, which constitutes about 99% of the interstellar matter, consists mostly of hyd...

exobiology

(Encyclopedia)exobiology or astrobiology, search for extraterrestrial life within the solar system and throughout the universe. Philosophical speculation that there might be other worlds similar to ours dates back ...

sailing

(Encyclopedia)sailing, as a sport, the art of navigating a sailboat for recreational or competitive purposes. Although sailing as a means of transportation predates history, sport sailing—or yachting—seems to...

zirconium

(Encyclopedia)zirconium zərkōˈnēəm [key], metallic chemical element; symbol Zr; at. no. 40; at. wt. 91.224; m.p. about 1,852℃; b.p. 4,377℃; sp. gr. 6.5 at 20℃; valence +2, +3, or +4. Zirconium is a very ...