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slotted armature
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References
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Periodical Cicada, Adult, Magicicada spp. Requires 17 years to complete development. Nymph splits its skin, and transforms into an adult. Feeds on sap of tree roots. Northern Illinois Brood. This brood is the largest emergence of cicadas anywhere
Why Do Some Cicadas Appear Only Every 17 Years?
Cathedrale St.Jean in Lyon, France has a 14th-century astronomical clock that shows religious feast days till the year 2019; Perpetual Calendar
Ten Days That Vanished: The Switch to the Gregorian Calendar
Ethel Rosenberg arrested in August 1950. Photograph dated Aug. 8, 1950. American civilians executed for espionage. Spies, communists, Julius Rosenberg
Spies Like Us: 10 Famous Names in the Espionage Game
Berries and leaves of the bittersweet nightshade (Solanum dulcamara) plant. Poisonous plant
7 of the World’s Deadliest Plants
Drinking water is poured into a glass.
Water Fluoridation: Just the Facts
Aspirin pills.
7 Drugs that Changed the World
Illustration for Demystified "How Dangerous is Quicksand"
How Deadly Is Quicksand?

slotted armature

machine part

Learn about this topic in these articles:

invention by Wenström

  • Understand how the concept of touch changes with the presence of electrons between two objects
    In electromagnetism: Development of electromagnetic technology

    The slotted armature, still in use today, was invented in 1880 by the Swedish engineer Jonas Wenström. Faraday’s 1831 discovery of the principle of the alternating-current (AC) transformer was not put to practical use until the late 1880s when the heated debate over the merits of…

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