Re: A thread that has nothing to do with memes or the

James Rogers (
Wed, 04 Dec 1996 14:01:52 -0800

At 11:58 AM 12/4/96 -0800, you wrote:
>From: James Rogers <>
>> There is a type of "active" composite that has the properties you are
>> describing. It is a laminate composite consisting of piezo-electric
>> ceramics and shape-memory alloys from the nickel-titanium family.
>> When vibrations hit the ceramic outer laminate, the ceramic acts as a
>> transducer, converting the vibration into an electrical signal. The signal
>> is inverted (It may be inverted via an anisotropic material property. I am
>> not sure.) and fed into the shape-memory alloy. The alloy flexes and
>> reproduces the inverted signal, similar to a speaker, through the ceramic.
>This is an interesting discussion, which I unfortunately don't know enough
>solid state physics to contribute to.
>However my instincts are that some of these ideas are based on a macroscopic
>model which won't work at the level we are talking about. These atomic
>vibrations are themselves heat. The notion of going in and producing
>counter vibrations which will cancel these smacks of violating the Third

You are probably correct. I am not sure at what point these properties
would be irrelevant. I guess it would depend on exactly how "macro" your
nanostructure was.

One possible solution is to use magnetic fields for cooling. I know this is
done for ultra-cool liquid Helium applications. 1) Use the dipole moment of
the atom to restrict its motion (like a magnetic bottle), or 2) Increase the
entropy (and therefore decrease the enthalpy) of the system by using a
switched magnetic field.

How this would be implemented on a nano scale is not so clear to me...

-James Rogers