[NewCandle] Contact Potential and Charge

[Frederick Sparber]

How much Charge could you put in a Faraday Pail if you
rolled a pound of Copper Nanospheres down an Aluminum
tube?

Does Steel birdshot comming out of a brass cannon
have the same trajectory as it would out of an iron cannon?? :-)

Fred


On 8/14/07, Frederick Sparber <fsparber at gmail.com> wrote:
>
> *http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/28/29491/01337047.pdf?arnumber=1337047
> *
> **
> *Contact charging between metals revisited
> *Castle, G.S.P.; Inculet, I.I.; Sines, G.S.; Schein, L.B.
> Industry Applications, IEEE Transactions on
> Volume 40, Issue 5, Sept.-Oct. 2004 Page(s): 1226 - 1230
> Digital Object Identifier   10.1109/TIA.2004.834038
> *"Summary:* The theory of contact charging between metals was established
> in 1951 by Harper and confirmed experimentally in 1975 by Lowell who
> measured the net charge after separation of pure metals in contact and
> related it to the contact potential difference and capacitance of the
> surfaces using a specialized measurement technique. It is generally assumed
> that these contact charges can be ignored for metals used in common
> industrial processes because of charge backflow on separation. A series of
> experiments carried out on commonly used industrial materials shows that net
> charge does exist on spherical metal balls rolling out of a metal tube into
> a Faraday pail. The experiments were carried out using three different tube
> materials (copper, brass, aluminum), five different ball materials (copper,
> brass, aluminum, steel, and stainless steel), for ball diameters ranging
> from 0.24 to 1.27 cm. The surfaces of the materials were only rinsed with
> water and dried. Analysis of the results shows general agreement with the
> Harper theory and confirms the presence of net charge on metals separated in
> this simulated industrial operation, i.e., moving metal parts off a
> conducting conveyor. This process is analyzed from the point of view of
> possible discharge hazards and the reasons why this phenomenon is not more
> widely observed in industrial processes are discussed."
> **
> *Copper Clad Steel BBs:*
>
> *http://images.google.com/imgres?imgurl=http://www.pyramydair.com/blog/images/daisy-precision-bb-web.jpg&imgrefurl=http://www.pyramydair.com/blog/2006/10/who-makes-best-bbs.html&h=286&w=281&sz=12&hl=en&start=2&um=1&tbnid=8gCUAoy1AjnrjM:&tbnh=115&tbnw=113&prev=/images%3Fq%3Ddaisy%2Bbbs%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DN
> *
> **
> *" How BBs are made
> *A BB starts out as a piece of steel wire that is chopped into rough
> chunks quite a bit larger than BB size. Those chunks are fed to two steel
> plates that have a long spiral tapering groove. One plate turns while the
> other remains stationary, which rolls the rough chunk into a sphere. From
> there, it goes on to grinding, where it is reduced in size to the desired
> caliber. Next, it gets a flash plating of some anti-oxidant, such as copper
> or zinc. Then, it's sorted by centrifugal force in a long spiral slide. The
> good BBs go on to packaging and the rejects become scrap. *I saw this
> process in the Crosman plant, where they produce 10 million BBs every
> workday."*
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://ipdiscover.com/pipermail/newcandle_ipdiscover.com/attachments/20070814/dfefa8dd/attachment.html