You wrote;
> "If you heat one side of the stack while keeping the other side cool,
> you produce acoustic power, which could be converted to electricity
> or which could power another acoustic driver to produce cooling
> elsewhere in the system," he says. Mongeau demonstrates this
> principle in his lab by dipping the open end of a device into liquid
> nitrogen, where it becomes super-cold. "When we take it out, it
> warms up and a self-sustained oscillation is created inside. It
> starts singing."
...Fascinating!! Thanks for sharing that! I didn't see any explanation
of why they think this occurs, any ideas?
The basic description of the device;
It looks something like a large doorknob with a long shaft, and here's
how it works:
The device is essentially a hollow metal tube, which varies in diameter
along its length and is capped on one end. Attached at the opposite end
of the tube is an acoustic driver - a vibrating diaphragm similar to a
loudspeaker, but sturdier and more powerful.
As the diaphragm vibrates, gas atoms pressurized to 20 atmospheres
inside the enclosure oscillate back and forth, which sets up pressure
fluctuations.
"Fluctuating pressures inside the cavity are accompanied by a
fluctuation in temperature," Mongeau explains. "When you compress a gas
quickly it becomes warmer, and when you decompress it quickly, it
becomes cooler. The gas particles within the device are becoming
alternately hot and cold, dynamically, at a typical frequency of 200
Hertz, or 200 oscillations per second."
The gas atoms transfer their heat to and from a piece of porous material
called a stack, which is located near the acoustic driver. The end
result is that heat is pumped toward the driver, cooling the side of the
stack farthest away from the driver.
"The pressure fluctuations propagate as sound waves that are very loud,
around 180 decibels," Mongeau says. "If you were inside, it would be
unbearable to listen to."
-----------
Wow, sounds like a WAND or a Kings SCEPTRE, staff with a big ball on the
end???? What if that had a caduceus wound around the staff...uh-oh,
what gives here (besides my faded brain going off on tangents)? A
symbolic representation of technology whose original use had been lost
and so relegated to ritual?
A better image of that I found at;
http://www.bre.co.uk/bre/indoorenv/cool/acoustic.htm
NAVY shipboard thermoacoustic cooler with power levels and pictures;
http://www.acs.psu.edu/users/anat/SETAC.html
During this sea trial SETAC provided 419 W of useful cooling power with
an acoustic power input of 227 W, at a cold temperature of 21 °C and a
stack temperature difference of 30 °C.
(isn't 491 Watts of 'cooling power' greater than 227 Watts of 'acoustic
power input'?????)
----------------
excellent innovate cooling page;
http://www.bre.co.uk/bre/indoorenv/cool/index.htm#bre_logo
compressor induced oscillation to produce cooling;
http://www.bre.co.uk/bre/indoorenv/cool/pulse.htm
----------------
Hamel (with the Hamel flying disk) says he was told by his 'contacts'
that mankind has over and over again been given simple technology to
control gravity, produce light, energy and heat, etc...but always loses
it somehow...the purpose being to give mankind a chance to save itself
before an upcoming cataclysm.
According to him, we are expected to build as many ships as possible,
save as many as possible by moving them to space or another planet, let
the earth go through its climatic changes, then return when everything
again stabilizes, to repopulate and repollute for the next
cycle...<g>...
Since reading that the moon 'rang like a bell' when a charge was set off
underground on a moon mission, it seems the moon is hollow with an
outside shell that vibrates just like a bell. Odd that 30 years later,
we still haven't returned and at the very least setup colonies there?
I have been suspecting it is one giant hotel, built by ancients
(possibly with attention misdirected by reports of the lost
Shamballa/Agharta claims being INSIDE the earth when really they are in
a hollow moon) as a sanctuary for some of our people when the earth
faced impending catastrophe.
The hollow moon would have life support systems, energy production
devices, rooms, water, waste disposal and whatever else was needed to
support life. It would be expected that we would build our own ships
and rescue as many as possible as a seed race that would be allowed to
survive the cataclysms, then return to repopulate.
I don't just base this lost technology speculation as attibuted solely
to Hamel but to many of the reports and even extant wonders like the
obelisks, Baalbek, the pyramids and other structures and phenomena that
indicate some kind of unknown technology.
The one report about the various sized odd tuning forks hidden away in
the Egyptian museums and classed as 'unknown' or religious artefacts.
However, that is getting off topic for this singing thread.
Another correlation to cooling using unsual methods was from Jack Veach
who first told me about 'magnetocalorics' which is a way to cool using
high density magnetic fields swept through a ceramic surrounding a
heated core. Somehow the magnetic field acts like a bucket brigade to
move the heat from the very hot inner core to the outside edge where it
dissipates, thereby cooling the mass.
Woody (from the old BBS) first told us about seeing one of these
acoustic refrigerators in a lab that he visited. He said one of the
engineers he was consulting asked him if he'd like a Coke, reached into
a box and pulled out a chilled drink. Woody said it was unlike any
refrigerator he ever saw and made a muffled humming sound. They
explained it as a prototype refrigerator that used Sound. So its great
to see more details coming out about it.
good overall paper on magnetocalorics;
http://positron.aps.org/BAPSMAR98/abs/S3220.html
recently discovered giant magnetocaloric effect;
http://epswww.epfl.ch/aps/BAPSMAR98/abs/S3220003.html
This 'singing' effect is intriguing and while hunting for additional
info I did find that it is called 'acoustic emission' as explained at;
http://www.msm.cam.ac.uk/phase-trans/abstracts/sing.html
Transformations that happen very rapidly frequently emit sound, a
phenomenon known technically as "Acoustic Emission". In the course of
studies of the transformation behaviour of high carbon steel during
cooling from the austenitic condition, Francisca Garcia Caballero
discovered that the steel "began to sing".
This site also offers a 5MB audio file of this 'singing' sound if you'd
like to download it.
----------------
One final correlation is the crackling, snapping sounds of the
'Barkhausen' effect. Supposed to sound like sand grains falling over
each other as a bucket of sand is tilted.
http://pmmh.espci.fr/~zapperi/avalanches/node5.html
The Barkhausen effect was first observed in 1919 in the magnetization
curve of ferromagnets. The magnetization as a function of the field is
not smooth but increases in steps. This steps are noticeable in the form
of of a noise with interesting properties. The Barkhausen effect is due
to the disorder in the material wich is responsible for the jerky motion
of domain walls. The amplitude of the noise is well described by a gamma
distribution and it is possible to identify avalanches which are
typically power law distributed. The exponents have been found to be
universal in a large class of materials.
page showing animated graph of barkhausen clicking transitions;
http://alpha.ien.it/~durin/barkh.html
overview of how to measure Barkhausen noise;
http://phy-server.phy.queensu.ca/wwwhome/atherton/barkhausen.html
more animated gifs of the Barkhausen effect;
http://alpha.ien.it/~durin/bk_intro.html
Feynmans experiment on how to easily detect Barkhausen crackling;
http://simscience.org/crackling/Advanced/Magnets/BarkhausenExperiment.html
----------------
Recently, there are people claiming all kinds of unusual things related
to the Barkhausen effect and free energy. Anything to make a sale.
-- Jerry Wayne Decker / jdecker@keelynet.com http://keelynet.com / "From an Art to a Science" Voice : (214) 324-8741 / FAX : (214) 324-3501 KeelyNet - PO BOX 870716 - Mesquite - Republic of Texas - 75187