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sleet

(Encyclopedia)sleet, precipitation of small, partially melted grains of ice. As raindrops fall from clouds, they pass through layers of air at different temperatures. If they pass through a layer with a temperature...

americium

(Encyclopedia)americium ămərĭˈshēəm [key], artificially produced radioactive chemical element; symbol Am; at. no. 95; mass no. of most stable isotope 243; m.p. about 1,175℃; b.p. about 2,600℃; sp. gr. 13....

Mediterranean Sea

(Encyclopedia)CE5 Mediterranean Sea [Lat.,=in the midst of lands], the world's largest inland sea, c.965,000 sq mi (2,499,350 sq km), surrounded by Europe, Asia, and Africa. Some of the most ancient civilizat...

Vieques

(Encyclopedia)Vieques vyāˈkās [key], island (1990 pop. 8,602), 51 sq mi (132 sq km), off E Puerto Rico. It is hilly, with a dry, warm climate. The town of Vieques, commonly called Isabel Segunda, was founded in ...

insulation

(Encyclopedia)insulation ĭnˌsəlāˈshən, ĭnˌsyo͝o– [key], use of materials or devices to inhibit or prevent the conduction of heat or of electricity. Common heat insulators are, fur, feathers, fiberglass, ...

ventilation

(Encyclopedia)ventilation, process of supplying fresh air to an enclosed space and removing from it air contaminated by odors, gases, or smoke. Proper ventilation requires also that there be a movement or circulati...

United States Air Force Academy

(Encyclopedia)United States Air Force Academy, at Colorado Springs, Colo.; for training young men and women to be officers in the U.S. air force; authorized in 1954 by Congress. Temporary quarters were opened at th...

Wright-Patterson Air Force Base

(Encyclopedia)Wright-Patterson Air Force Base, U.S. military installation, 8,023 acres (3,247 hectares), W Ohio, NE of Dayton; est. 1917. One of the largest airport installations in the world, it is the air force's...

cloud

(Encyclopedia)CE5 Approximate heights of some types of clouds cloud, aggregation of minute particles of water or ice suspended in the air. Cloudiness (or proportion of the sky covered by any form of cloud),...

dark matter

(Encyclopedia)dark matter, material that is believed to make up nearly 27% of the mass of the universe but is not readily visible because it neither emits nor reflects electromagnetic radiation, such as light or ra...