Ultrasonic Bibliography Page 3 - Selected Articles.
CALL FOR CONTRIBUTIONS: I am writing a book on "High-Intensity Ultrasonic Technology and Applications" (intended for Marcel Dekker's "Mechanical Engineering Series", edited by Profs. Lynn L. Faulkner and S. Bradford Menkes). This book will focus on the practical application of power (high intensity) ultrasonics, the use of ultrasonic energy to change materials. Contributions are welcome.
THE CAVITATION BUBBLE
[image from University of Washington, Applied Physics Laboratory (Lawrence Crum, Ph.D.)
- bubble diameter approximately 1mm]
Magnetostriction
As noted previously under Magnetostrictive Transducers on the Ultrasonic Cleaning page, and in the ULTRASONICS GLOSSARY, magnetostrictive materials expand and contract in an alternating magnetic field.
Unlike the more commonly-used electrostrictive (crystal) transducers;
magnetostrictive transducers are often utilized for their greater maximum
strength, output, and temperature-resistance. They differ from electrostrictive
transducers in that, instead of being pulsed by an alternating electrical
current, they are pulsed by an alternating magnetic field. A stack of
thin shim stock (usually nickel) is brazed together and surrounded by a magnetic coil;
alternating the polarity of the current passed through the coil alternates the polarity
of the magnetic field. Nickel (or any other magnetostrictive material) expands
and contracts in altrnating magnetic fields (much as electrostrictive crystals do in an
alternating electrical field). Shims are used instead of solid blocks to avoid
destructive eddy currents. The stacks are usually of a high aspect ratio (long
and thin) and are kept from balooning by a strap at the nodal point. In keeping
with their high power ratings, magnetostrictive transducers are usually brazed
together and often brazed to the tank bottom (or stack) or to a block bolted to the
tank (or stack). They also may require air or liquid cooling to function at high
power and elevated temperature; however, there is a positive corollary.
Magnetostrictive transducers, able to function at high temperatures, are ideal for use
on solder pots and dip-galvanizing tanks.
Ignoring the destructive eddy-current problem for a moment, here is how a
magnetostrictive material functions (a crude block is shown in cross-section for
simplicity):
(23 Aug 02 illustrations by and © 2002 S. Berliner, III - all rights reserved)
[The rows of circles represent the electrical coil generating the magnetic field]
Crude though these be, the illustrations show how the alternating field forces the
material radially inward, which (because of conservation of mass) forces the ends
outward, the material at rest, and the material responding elastically when the field
reverses, pulling the ends inward.
Thus, the action is really no different than it is with electrostrictive devices. The
net result in either case is that the ends of the transducer move in and out cyclically.
If a front driver and tool (horn) are attached to one end, work can be performed.
As with electrostrictive devices, a "counterweight" (back driver) is required to provide
a resonant body.
{preliminary - more to follow on magnetostriction, carrying forward the information
already on Magnetostrictive Transducers.}
Giant Magnetostrictive Materials
A piezomagnetic material (a "lanthanide") was developed by the Naval Ordnance Lab
[now the Naval Surface Warfare Center (NSWC)] in Ames, Iowa, for use in sonar, that
was found to have all the desirable properties of piezoceramics while exhibiting the
strength and power capabilities of metallic magnetostrictive elements. It is
named TERFENOL-D® for its constituent metallic
elements and the Lab; terbium (TER), iron (FE),
Naval Ordinance Labs (NOL), and Dysprosium.
TERFENOL-D® is licensed to, and being actively developed by:
ETREMA Products, Inc.
2500 N. Loop Drive
Ames, Iowa 50010
515-296-8030
{preliminary - more to follow on "giant magnetostrictive materials", specifically
"giant magnetostrictive lanthanides"
most commonly known as TERFENOL-D®.}
{more to follow on this topic}
For more information, please contact S. Berliner, III.
Call for Contributions
For the forthcoming book, "High-Intensity Ultrasonic Technology and
Applications", on the application of power (high intensity) ultrasonics, the
use of ultrasonic energy to change materials, I solicit input and refer you to the new
Continuation Page 1 where details of this request
have been moved.
Please note that a far-more detailed explanation of ultrasonic processing, as well as
other technical literature, is available at no charge to consultation clients.
However, as what I believe to be a public service, I shall be adding more of my
monographs on ultrasonics on this site; watch for them in the
index.
You may wish to visit main ULTRASONICS page,
Continuation Page 1,
Continuation Page 2, and Continuation Page 3 with
more on ultrasonics, as well as the Ultrasonics
Cleaning page {in process} and the Ultrasonics Glossary
page {also in process}.
Those persons interested in SONOCHEMISTRY might wish to look at
Prof. Kenneth S. Suslick's and
Shiga
University's Sonochemistry pages.
The author gratefully acknowledges inclusion of these pages
in INTUTE: Science, Engineering and Technology
[formerly EEVL - the Enhanced and Evaluated Virtual Library
The Internet Guide for Engineering, Mathematics and Computing
(previously the Edinburgh Engineering Virtual Library)
a service of the Heriot-Watt University funded by the JISC.]
LEGACY
What happens to all this when I DIE or
(heaven forfend!) lose interest? See LEGACY.
THUMBS UP!
THUMBS UP! - Support your local police, fire, and emergency personnel!
S. Berliner, III
To contact S. Berliner, III, please click here.
© Copyright S. Berliner, III -
2001, 2002, 2004,
2008
- All rights reserved.
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