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Posts Tagged ‘Stoneridge Engineering

Turning two bits into… well, about 1.6 bits…

In case the economic turmoil of the last year or so hasn’t done enough to reduce the size of one’s assets, the good folks at Stoneridge Engineering (motto:  “wreaking havoc with electrons for over forty years”) have gone public with information which can help:  “All About Quarter Shrinking (or “Makin’ Small Change”©).”

Before and After

As Stoneridge explains:

The Quarter Shrinker uses a technology called high velocity electromagnetic forming, or “Magneforming.” This is a “high energy rate” process that was originally developed by the aerospace industry in conjunction with NASA…  It involves quickly discharging a high energy  capacitor bank through a work coil to generate an extremely powerful, rapidly changing magnetic field which then “forms” the metal to be fabricated. The technique uses pulsed power to generate a very high current pulse over a very short time interval… To shrink coins, I charge up a large high voltage capacitor bank consisting of a number of large “energy discharge” capacitors. Each capacitor is specially designed to reliably store up to 12,000 volts and deliver 100,000 ampere discharges.

The initial energy stored within the capacitor bank is typically in the range of 3,500 – 6,300 Joules (watt-seconds). Because this energy is discharged in as little as 20 millionths of a second, the instantaneous power is very large and, for a brief instant, is roughly equivalent to the electrical power consumed by a good sized city. The repulsion forces between the work coil and the coin create tremendous radial compressive forces that easily overcome the yield strength of  the metal alloys in the coin, causing the coin to plastically deform into a smaller diameter. The higher the initial energy, the greater the degree of “shrinkage”. Applying a 6,300 joule pulse results in a quarter whose final diameter is about 0.1″ SMALLER than a dime!

See a video demo and more photos– the technique works on other coins too!– here.

(Oh, and lest one wonder: the title of this post notwithstanding, a shrunken coin weighs exactly the same as before, and its density is unchanged. The coin becomes thicker as its diameter is reduced; the overall volume stays the same.)
As we call it, heads or tails, we might note– or then again, we might not be able to note– that on this date in 1775 invisible ink was developed by James Jay, a physician and the brother of John Jay.  Dr. Jay was knighted by George III before the “unpleasantness with the Colonies”…  he might have rethought the bestowal had he known that Jay was using the “stain” for reporting military information from London to America.

source: LoneRanger on Final4Ever

Written by (Roughly) Daily

November 29, 2009 at 1:01 am

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