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quantum chromodynamics

(Encyclopedia)quantum chromodynamics (QCD), quantum field theory that describes the properties of the strong interactions between quarks and between protons and neutrons in the framework of quantum theory. Quarks p...

telegraph

(Encyclopedia)telegraph, term originally applied to any device or system for distant communication by means of visible or audible signals, now commonly restricted to electrically operated devices. Attempts at long-...

water power

(Encyclopedia)water power, mechanical energy derived from falling or flowing water, e.g., rivers, streams, and the overflow of dams. The wooden water wheel, long utilized for driving machinery in flour mills and fa...

utility, public

(Encyclopedia)utility, public, industry required by law to render adequate service in its field at reasonable prices to all who apply for it. Public utilities frequently operate as monopolies in their market. In th...

ironwork, ornamental

(Encyclopedia)ironwork, ornamental. The shaping of wrought iron, used almost exclusively until the 16th cent., is primarily an art of the blacksmith, who must work with the metal while it is at the desired stage of...

drill, tool

(Encyclopedia)drill, tool used to create a hole, usually in some hard substance, by its rotary or hammering action. Many different tools make up the drill family. The awl is a pointed instrument used for piercing s...

Columbia, cities, United States

(Encyclopedia)Columbia kəlŭmˈbēə [key]. 1 City (2020 pop. 104,681), Howard co., central Md., between W...

chromium

(Encyclopedia)chromium krōˈmēəm [key] [Gr.,=color], metallic chemical element; symbol Cr; at. no. 24; at. wt. 51.9961; m.p. about 1,857℃; b.p. 2,672℃; sp. gr. about 7.2 at 20℃; valence +2, +3, +6. Chromiu...

signaling

(Encyclopedia)signaling, transmission of information by visible, audible, or other detectable means. Since prehistoric times humans have sought and employed ever more effective means of communicating over distance....

Saint Lawrence Seaway

(Encyclopedia)Saint Lawrence Seaway, international waterway, 2,342 mi (3,769 km) long, consisting of a system of canals, dams, and locks in the St. Lawrence River and connecting channels between the Great Lakes; op...