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22 Topic Pages Found in Technology & Engineering and starting with the letter R
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Open 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

Open Radio

Radio was the first global electronic medium. It dominated public communications on local, national, and global levels in the 20th century, and it

radiocarbon dating

Method of dating organic materials (for example, bone or wood), used in archaeology. Plants take up carbon dioxide gas from the atmosphere and

Open Radio frequency identification systems
Radio frequency identification systems

Radio frequency identification (RFID) technology is a wireless radio-frequency technology that uses radio waves to transfer information for the

Open radiometer

( rā´´dēŏm'ətər ), instrument for detection or measurement of electromagnetic radiation ; the term is applied in particular to devices used to measure

Open radio telescope
radio telescope

Instrument for detecting radio waves from the universe in radio astronomy . Radio telescopes usually consist of a metal bowl that collects and focuses

Open railroad

or railway, form of transportation most commonly consisting of steel rails, called tracks, on which trains of freight cars, passenger cars, and other


production of rain by artificial means now generally disregarded, though it is probable that rainmaking hastens or increases rainfall from clouds

rammed earth

material consisting chiefly of soil of sufficiently stiff consistency that has been placed in forms and pounded down. It has been used for buildings

Open Rapid transit
Rapid transit

Rapid transit conveyances run on fixed routes, with regular stops, on frequent schedules, with set fares, and with separate rights-of-way. Subways and