Word: coils
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After his return to the U.S., Parker read about a new, inexpensive contraceptive device consisting of a pliable, doubleS plastic coil (TIME, July 31). "When I learned it worked on women," says Parker, "I thought: why won't it work on cows?" It does. After elaborate experiments at the Beltsville, Md., agricultural research center, India's Food and Agricultural Ministry enthusiastically launched a pilot project in the northern province of Uttar Pradesh. Of the country's 200 million cattle, some 75% are used as beasts of burden or as milk producers. The remaining 50 million are mostly...
...taught Columbus engineer, the "Sentronic" book detector works on the ancient principle of magnetism. A sliver of magnetized metal is hidden somewhere in a book's spine or binding, and the librarian who checks the book out simply demagnetizes the metal insert by passing the book through a coil carrying an electric current. If a thief bolts for the exit instead of the check-out desk, the magnetized metal inside his book is detected by an instrument that trips a solenoid hidden at the door; the turnstile is automatically locked and the librarian alerted. A sign over the door...
...high-power pulses of electrical energy throbbing through intricate circuitry are the heartbeats of modern radar. But they are the bane of many an electronics engineer. Sometimes the high-frequency currents that are crammed into a pulse swirl through a simple resistance as if it were also a small coil (inductance); sometimes the pulses treat the resistance as if it were a capacitor. Either way, coil or capacitor, those unwanted effects introduce annoying problems...
...mouth when people chew, drink or swallow, Dr. Samuel Adams II, 28, and his associates at Rochester, N.Y.'s Eastman Dental Dispensary, have been bugging the bridgework of volunteers with tiny radio transmitters fitted into dummy teeth. Crammed inside each electronic tooth are a transistor, an induction coil, two capacitors, a resistor and a hearing-aid battery- all miniaturized items developed by the Air Force. Once the radio denture is in place, the subject enters a Faraday cage, a metal-mesh enclosure that blocks out most outside electrical disturbances. As the subject chews and drinks in his static-free...
...different coils do different jobs. When the end of a metal tube is inserted into the doughnut-shaped coil, it can be shrunk tightly around any insert such as a plug or a threaded fitting. To expand a metal tube, a cylindrical coil is pushed inside it. A flick of the switch, and the tube expands to bind itself solidly to whatever surrounds it. To stamp a flat piece of metal with a pattern, a trademark of elaborate lettering, the metal is placed between a flat coil and a die. When the coil is activated, the opposing magnetic field...