power direction relay
71Diode — Figure 1: Closeup of a diode, showing the square shaped semiconductor crystal (black object on left) …
72Railway signalling — Not to be confused with Railway signal. A gantry of British semaphore signals seen from the cab of a steam locomotive Railway signalling is a system used to control railway traffic safely, essentially to prevent trains from colliding. Being… …
73Automatic Packet Reporting System — (APRS) is an amateur radio based system for real time tactical digital communications of information of immediate value in the local area. In addition, all such data is ingested into the APRS Internet system (APRS IS) and distributed globally for …
74Non-line-of-sight propagation — Non line of sight (NLOS) or near line of sight is a term used to describe radio transmission across a path that is partially obstructed, usually by a physical object in the innermost Fresnel zone. Many types of radio transmissions depend, to… …
75railroad — /rayl rohd /, n. 1. a permanent road laid with rails, commonly in one or more pairs of continuous lines forming a track or tracks, on which locomotives and cars are run for the transportation of passengers, freight, and mail. 2. an entire system… …
76Space Shuttle — STS redirects here. For other uses, see STS (disambiguation). This article is about the NASA Space Transportation System vehicle. For the associated NASA STS program, see Space Shuttle program. For other shuttles and aerospace vehicles, see… …
77Communications satellite — A communications satellite (sometimes abbreviated to COMSAT) is an artificial satellite stationed in space for the purpose of telecommunications. Modern communications satellites use a variety of orbits including geostationary orbits, Molniya… …
78Danger Hiptop — Manufacturer Danger Incorporated / Flextronics / Sharp Corporation / Motorola Carriers T Mobile (2002 2010) Telstr …
79Italy — /it l ee/, n. a republic in S Europe, comprising a peninsula S of the Alps, and Sicily, Sardinia, Elba, and other smaller islands: a kingdom 1870 1946. 57,534,088; 116,294 sq. mi. (301,200 sq. km). Cap.: Rome. Italian, Italia. * * * Italy… …
80Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity. Computer scientist Manindra Agrawal of the… …
