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Re: Diffusion Machine Update -- REFUTATION

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  • mintowheel
    Hi Bob and Gary, I thought of the same simplification to the diffusion PMM proposal that Gary just suggested -- eliminating the top semi-permeable membrane. I
    Message 1 of 10 , Dec 2, 2004
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      Hi Bob and Gary,

      I thought of the same simplification to the diffusion PMM proposal
      that Gary just suggested -- eliminating the top semi-permeable
      membrane. I came to the same conclusion as Bob. Getting rid of the
      top membrane, although seemingly a simplification, actually would
      make the device much more difficult to build and operate (assuming
      it works at all). Also, due to the great vertical length of the
      solution column (many meters to kilometers!), the time needed for
      the solution to diffuse back to equilibrium (after each portion of
      water dripped onto it) would be much much longer. So the top
      membrane serves a very important purpose in this scheme by apply
      downward osmotic pressure to the inside of the solution column,
      thereby counteracting the bottom membrane (which generates upward
      osmotic pressure). In other words, the top membrane takes the place
      of that 7 kilometer high column of solution. As I mentioned in my
      previous post in this thread, any dilution of solute concentration
      at the top membrane will cause all cyclic flow to stop due to
      lessening of the downward osmotic pressure. This is why the
      critical issue for this design becomes whether or not the solution
      will regain, via diffusion/Brownian motion, its initial uniform
      concentration. Bob thinks that it should be possible for the
      solution to become uniform again; I assert that the solution will
      instead (in the absence of any imposed mixing), due to gravity,
      settle into a concentration gradient with low concentration at the
      top (and at an extremely slow rate on the order of months).

      Getting back to Gary's one-membrane scenario, note that others have
      proposed this before. Have a look at the Museum of Unworkable
      Devices to see a related idea, which, although employing a different
      topology, is supposed to work by exactly the same principle. They
      use only one membrane, and they use the ocean as their salt solution:

      http://www.lhup.edu/~dsimanek/museum/annex.htm#osmosis

      The skeptics who analyze perpetual motion machines at that site
      offer an explanation of why the device should not work. They got
      their "refutation" completely wrong. Their explanation boils down
      to the assertion that the density of the solution does not matter.
      Wrong! I think that the device would actually work, but it would
      not violate the second law because the high concentration of salt
      solute near the membrane would de dispersed by ocean currents.
      Natural sources of energy (ultimately derived from solar energy)
      would power the device, not a second law violation.

      Thank you gentlemen for contributing to this fascinating
      discussion. Bob, I will do some more literature searches to see if
      I can find real-life examples to back up my claim that the solute in
      a solution settles due to gravity. If anyone knows of such
      information, please let us know.

      Regards, Leo Cabana


      --- In free_energy@yahoogroups.com, "Robert Lerwill" <bob.mo@v...>
      wrote:
      > Hi Gary,

      <SNIP>

      > Your second question is a good one. The top membrane is actually
      not strictly necessary but you would need a very tall column for the
      device to function without one. The osmotic pressure for a 10% sugar
      solution is 7atm (700kP) and the SG is 1.01. This osmotic pressure
      is enough to support a column of solution 69.3 metres high. Using
      the equation I gave above for the head of water, to get enough
      pressure difference to create any flow at all would need a 10% sugar
      solution column at least 7km high (i.e. 69.7/(1.01 - 1). Perhaps is
      might be possible in the Marianas trench, but I don't think I could
      get one in my shed.
      >
      > Bob Lerwill



      > ----- Original Message -----
      > From: Gary S.
      > To: free_energy@yahoogroups.com
      > Sent: Wednesday, December 01, 2004 5:04 PM
      > Subject: [free_energy] Re: Diffusion Machine Update -- REFUTATION
      >
      > Bob, I just reread your document.

      <SNIP>

      If the bottom membrane is correct
      > (water flows from solution to region of less concentration),
      wouldn't
      > you be better off at the top by just eliminating the upper
      membrane
      > altogether and just letting the drops fall into the solution?
      >
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