--- Paul <[EMAIL PROTECTED]> wrote: > --- Paul <[EMAIL PROTECTED]> wrote: > > > --- Robin van Spaandonk <[EMAIL PROTECTED]> > > wrote: > > > In reply to Paul's message of Wed, 11 Oct 2006 > > > 08:11:08 -0700 > > > (PDT): > > > Hi Paul, > > > [snip] > > > >contact with his daughter. BTW, do you have a > > > contact > > > >for five nines grade iron? > > > [snip] > > > Isn't pure iron just going to convert all those > > > lovely microwaves > > > into pure heat? > > > Regards, > > > > > > Robin van Spaandonk > > > > > > Hi Robin, > > > > Under normal usage the magnetic material absorbs > > most > > of the radiation. The radiation is typically in > the > > hundreds of MHz (not GHz) for non-electrical > > materials > > and considerably lower in frequency for > electrically > > conductive materials such as iron. In electrically > > conductive materials the free electrons act as > > inductance, which slows down the electrons flip > > rate. > > So in iron, depending on purity, the peak > radiation > > frequency ranges from KHz to MHz, not hundreds of > > MHz > > let alone GHz. Even if it were microwaves (GHz), > > which > > for the most part the radiation is not, the metal > > would act as a high refractive index. In other > > words, > > the metal would slow down the radiation velocity. > > Furthermore, most of the radiation would > internally > > reflect off the cores outer walls. Note that in > > microwave ovens the metal reflects the radiation-- > > only a small amount is absorbed. This process of > > slowing down the radiation and reflecting is > > understood when studying electrodynamics in > detail. > > Also you can see this effect in electrodynamic > > computer simulations. The end result would be most > > of > > the radiation reflecting internally, which would > > cause > > heat. Here's a list of methods to decrease the > > magnetic materials ability to absorb the radiation > > in > > addition to increasing the potential radiation. > > > > 1. Use materials with smallest domains at > operating > > temperatures-- amorphous and nanocrystalline > cores. > > The smaller the domain the more potential energy. > > When > > times permit I would like to precisely demonstrate > > this in a step-by-step process using conventional > > physics. > > 2. The thinner the core the better! Your goal is > to > > prevent the core from absorbing the MCE radiation. > > Presently I am pondering upon a design that uses > > long > > thin magnetic electrically conductive wires. The > > thin > > wire would be the core and coil. > > 3. High saturation materials. A fully saturated > core > > prevents the intrinsic electron spins from > absorbing > > the magnetocaloric energy. Of course a fully > > saturated > > core is useless, but no realistic coil can fully > > saturate magnetic material. The core should be > close > > to saturation. > > 4. Unless you use filters you'll need to flip the > > process so you can collect the energy during the > > cores > > radiating cycle. You do this with a permanent > > magnet. > > Also the PM helps saturate the core, but you don't > > want to fully saturate it. > > 5. The field from your coil will oppose the PM's > > field. So you slowly increase your coil current to > > decrease the cores net applied field and then you > > want > > to drop the current or reverse the current as > > quickly > > as possible (high di/dt). High di/dt causes a > higher > > percentage of the electron spins to flip > > simultaneously, which in turn greatly reduces the > > cores ability to absorb MCE energy, which allows > > more > > of the energy to escape the core. In short, ultra > > high > > di/dt lowers the effective permeability, which in > > turn > > prevents the core from absorbing a great deal of > the > > MCE energy, which your circuit can then properly > > absorb. If the core material has low electrical > > resistivity then the Eddy currents will absorb the > > radiating energy and then with precise timing you > > can > > rob a certain percentage of the Eddy currents > > energy. > > > > Robin, > > I should add there are two methods of extracting MCE > energy. If the material is electrically conductive > as > iron then it is probably best to allow the free > electrons to absorb MCE energy in the form of eddy > currents. At the precise moment the coil would > extract > as much eddy current energy as possible.
I've added a new section to the MEMM wiki project titled "First Released Details" --> http://peswiki.com/index.php/Directory:MEMM Paul Lowrance __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
