This report on acoustic surgery apparently uses phase
conjugation to cause a focused cutting or cauterizing
beam to appear inside the body.
http://www.aip.org/enews/physnews/1998/split/pnu380-1.htm
ACOUSTIC SURGERY is the use of sound in place of the
scalpel to perform such tasks as destroying tumors and
stopping internal bleeding.
At last week's joint meeting in Seattle of the
International Congress on Acoustics and the Acoustical
Society of America, Gail ter Haar of the Royal Marsden
Hospital in England (011-44-181-642-6011) described a
clinical trial in which focused sound waves destroyed
parts of liver, kidney, and prostate tumors in 23
patients.
Just as sunlight sent through a magnifying glass can
burn a leaf placed at the spot where the light
converges, sound broadcast through a specially shaped
set of speakers can converge inside the body to create
a region of intense heat that can destroy tumor cells.
The spot is so small that there is only a boundary of
six cells between destroyed tissue and completely
unharmed tissue--a precision that is finer than any
scalpel. Ter Haar said the next phase is to attempt
complete destruction of tumors in the liver and
prostate.
(See http://www.acoustics.org )
Meanwhile, Roy Martin of the University of Washington
(206- 685-1883) discussed the use of ultrasound to
stop internal bleeding in the liver.
Just as a grill heats a steak, the sound waves heat
the bleeding area to create chemical and physical
changes that cauterize it. Otherwise, liver surgery is
often hampered by bleeding, Martin said.
-----------
Therapeutic ultrasound;
http://asa.aip.org/web2/asa/abstracts/search6/asa1812.html
Apart from the high-intensity, surgical uses
(operating at peak intensities around 2 kW cm[sup
-2]), ultrasound has been applied amongst other things
to promote wound healing, to stimulate bone repair, to
accelerate healing in tendon injuries, and as a
thrombolytic agent. The majority of therapeutic
ultrasound techniques operate at intensities of 500 mW
cm[sup -2] or less (spatially averaged intensities).
------------
Just as an aside, these interesting URLs were also
found relating to sound;
Acoustic Weapons (very small excerpt follows);
http://www.acoustics.org/altmann.html
"How can one turn a threatening gunman into a retching
bundle of nerves, suffering simultaneously from bowel
spasms and loss of courage before surrendering to
police? Simply use infrasound on him, i.e., sound too
low in frequency to be heard. This is at least what
some military journals promise as the virtue of
so-called "acoustic weapons." What is more, these
reports always tend to claim something like, "The
effect ceases as soon as the generator is turned off,
with no lingering physical or environmental damage."
Potentially more harm is ascribed to "acoustic
bullets," (either low or high frequency),
baseball-sized objects which propogate to hundreds of
meters, causing incremental effects from discomfort to
death."
------------
Standing wave acoustic bubble traps (excerpt follows);
http://www.acoustics.org/geisler.html
"A few years ago D. F. Gaitan (in his Ph.D. work in
Oxford/Mississippi under the supervision of Prof. L.
A. Crum, now Seattle) developed a method to trap a
single sonoluminescing bubble within an acoustic
standing wave field. With this "hydrogen atom of
sonoluminescence" interactions between bubbles are
eliminated, and the undisturbed single-bubble dynamics
can be scrutinized. Such a bubble trap is realized by
taking advantage of a force already investigated at
the turn of the last century by C. A. and V. Bjerknes.
The force on an object in a liquid depends on its
volume and the pressure gradient. Normally this is
only the well-known static buoyancy induced by
gravitation. In the presence of a standing sound wave
there will be an additional gradient, which alternates
with the frequency of the sound. Since a small bubble
oscillates in phase with the sound pressure - small
volume in the high pressure phase, large volume in the
low pressure phase - one direction of the resulting
force will outweigh the other (see illustration).
Hence, the time averaged force drives the bubble
towards the antinode of sound pressure and keeps it
there."
------------
Mechanically or acoustically softened rocks;
http://www.acoustics.org/press_release.html
"Rocks have some very unusual properties that
researchers are only beginning to discover. As
explained by James A. TenCate of Los Alamos
(tencate@lanl.gov), repeatedly expanding and
compressing sandstone rock with high-magnitude strain
forces can "condition" the rock to respond with less
stiffness to the applied forces after a few minutes,
so that it behaves like a softer spring. Intriguingly,
the rock remains soft for minutes or even hours,
constituting a sort of "memory" of the past forces
applied to it (4aPAc11). Paul Johnson of Los Alamos
(paj@lanl.gov) will describe how the rock's elastic
properties seem to originate from processes at the
mesoscopic scale (between the microscopic and the
macroscopic), unlike liquids and crystalline solids,
whose elasticity properties are determined by
atomic-scale forces. Surprisingly, the researchers
discovered damaging an atomic elastic material" causes
it to behave like a "mesoscopic" elastic material
(4aPAc9)."
------------
Doesn't this rock business sound a lot like the
Reynolds 'dilatant matrix' information? at;
http://www.keelynet.com/energy/reynold1.txt
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