positioning plate
51Crystal oscillator — A miniature 4 MHz quartz crystal enclosed in a hermetically sealed HC 49/US package, used as the resonator in a crystal oscillator. A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal …
52Four-wheel drive — This article is about the class of vehicle drivetrains. For other uses, see Four by four/Four wheel drive (disambiguation). All wheel drive redirects here. For the all wheel drive in motorcycles, see two wheel drive. The Jeep Wrangler is a 4WD… …
53tunnels and underground excavations — ▪ engineering Introduction Great tunnels of the world Great tunnels of the worldhorizontal underground passageway produced by excavation or occasionally by nature s action in dissolving a soluble rock, such as limestone. A vertical opening …
54Computed radiography — Contents 1 Differences from Direct Radiography 2 Imaging plate 3 Industrial applications …
55Drum brake — A drum brake with the drum removed as used on the rear wheel of a car or truck. Note that in this installation, a cable operated parking brake uses the service shoes …
56History of timekeeping devices — For thousands of years, devices have been used to measure and keep track of time. The current sexagesimal system of time measurement dates to approximately 2000 BC, in Sumer. The Ancient Egyptians divided the day into two 12 hour periods, and… …
57Inline roller skating tricks — A roller blade trick is a maneuver performed on roller blades. A general consensus of trick names exists, however, all are subjective to the individual and/or local popularity as they are all slang terms which are constantly debated over.… …
58Art, Antiques, and Collections — ▪ 2003 Introduction In 2002 major exhibitions such as Documenta 11 reflected the diverse nature of contemporary art: artists from a variety of cultures received widespread recognition for work ranging from installation to video to painting …
59German cruiser Admiral Graf Spee — Admiral Graf Spee in 1936 Career (Nazi Germany) …
60Pressure measurement — The construction of a bourdon tube gauge, construction elements are made of brass Many techniques have been developed for the measurement of pressure and vacuum. Instruments used to measure pressure are called pressure gauges or vacuum gauges. A… …
