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electron tube

(Encyclopedia)CE5 Triode electron tube electron tube, device consisting of a sealed enclosure in which electrons flow between electrodes separated either by a vacuum (in a vacuum tube) or by an ionized gas at l...

Cook Islands

(Encyclopedia)Cook Islands, island group (2021 est. pop. 17,564), 90 sq mi (234 sq km), S Pacific, SE of Samoa; a self-governing state in free association with New Ze...

February Revolution, in French history

(Encyclopedia)February Revolution, 1848, French revolution that overthrew the monarchy of Louis Philippe and established the Second Republic. General dissatisfaction resulted partly from the king's increasingly rea...

sea level

(Encyclopedia)sea level, the level of the sea, which serves as the datum used for measurement of land elevations and ocean depths. Theoretically, one would expect sea level to be a fixed and permanent horizontal su...

polymer

(Encyclopedia)CE5 A. Addition polymerization: Two ethylene molecules, C2H4, combine to form two links in the polyethylene chain molecule (C2H4)n. B. Condensation polymerization: Two glycine molecules, NH2CH2COOH...

pipe

(Encyclopedia)pipe, hollow structure, usually cylindrical, for conducting materials. It is used primarily to convey liquids, gases, or solids suspended in a liquid, e.g., a slurry. It is also used as a conduit for ...

particle detector

(Encyclopedia)CE5 Particle detector—Bubble chamber: A. Pressure drops as piston is raised; B. Charged particles passing through chamber ionize atoms in liquid; C. Bubbles form around atoms and form visible tra...

Saffir-Simpson scale

(Encyclopedia)Saffir-Simpson scale săfˈər– [key], standard scale for rating the severity of hurricanes as a measure of the damage they cause; it is based on observations of numerous North Atlantic Basin hurric...

tropics

(Encyclopedia)tropics, also called tropical zone or torrid zone, all the land and water of the earth situated between the Tropic of Cancer at lat. 231⁄2°N and the Tropic of Capricorn at lat. 231⁄2°S. Every po...

Umayyad

(Encyclopedia)Umayyad o͞omäˈyäd [key], the first Islamic dynasty (661–750). Their reign witnessed the return to leadership roles of the pre-Islamic Arab elite, and the rejuvenation of tribal loyalties. The Ba...