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radar

(Encyclopedia)radar, system or technique for detecting the position, movement, and nature of a remote object by means of radio waves reflected from its surface. Although most radar units use microwave frequencies, ...

DEET

(Encyclopedia)DEET or N,N-diethyl-meta-toluamide, C12H17ON, nearly odorless, colorless to clear yellow oily liquid that boils at 111℃. DEET was developed by the U.S. Army in 1946 for use as an insect repellent an...

cryosurgery

(Encyclopedia)cryosurgery krīˈōsrˌjərē [key], bloodless surgical technique using a supercooled probe to destroy diseased or superfluous tissue. Liquid nitrogen circulating through the instrument cools it to t...

Caño Cristales

(Encyclopedia)Caño Cristales, river, c.62 mi (100 km) long, central Colombia, rising in Serranía de la Macarena National Park and flowing SE to the Guayabero River. Also known as the “River of Five Colors” or...

carbon black

(Encyclopedia)carbon black, mixture of partially burned hydrocarbons. Carbon black is produced by partial combustion of natural gas. It is used as a black pigment for inks and paints, and is used in large amounts b...

benzine

(Encyclopedia)benzine bĕnˈzēn, bĕnzēnˈ [key], colorless, highly flammable liquid. It is used as a cleaning agent because it is a solvent for organic substances such as fats, oils, and resins and is also used ...

Dee, John

(Encyclopedia)Dee, John, 1527–1608, English mathematician and occultist. He was educated at Cambridge. Accused of practicing sorcery against Queen Mary I, he was acquitted and later was a favorite of Queen Elizab...

Dubuque

(Encyclopedia)Dubuque dəbyo͞okˈ [key], city (2020 pop. 59,667), seat of Dubuque co., NE Iowa, on the Mis...

Erie, city, United States

(Encyclopedia)Erie, city (2020 pop. 94,831), seat of Erie co., NW Pa., on Lake Erie; inc. as a city 1851. Pennsylvania's only port on the Great Lakes, Erie is a busy ...

tourmaline

(Encyclopedia)tourmaline to͝orˈməlĭn, –lēn [key], complex borosilicate mineral with varying amounts of aluminum, iron, magnesium, sodium, lithium, potassium, and sometimes other elements, used as a gem. It o...