Recent Developments in the Use of Ultrasonic Attenuation Methods in Solid State Physics


Truell, R

Journal of the Acoustical Society of America 27(5): 1009-1009

1955


FORTY-NINTH
MEETING
1009
subjects
made
equal
loudness
balance
judgments
for
six
fre-
quencies
(200,
400,
1000,
1600,
and
4000
cps)
at
30
db
and
at
60
db
above
threshold
under
each
of
the
four
experi-
mental
pressure
conditions.
As
in
the
threshold
sensitivity
study
results
indicated
a
general
decrease
in
sensitivity for
frequencies
below
1000
cps
and
only
slight
effects
on
the
higher
frequencies.
The
effect
of
static
pressure
on
speech
intelligibility
was
also
studied
and
in
the
range
investigated
was
found
negligible.
This
work
was
done
at
Ohio
State
University.
J8.
The
Analogy
between
Cochlear
Fluid
Motion
and
Formation
of
Surf
on
Sloping
Beaches.
JUERGEN
TONNDORF,
University
Hospitals,
Iowa
City,
Iowa.—Peri-
lymphatic
fluid
motion
in
the
cochlea
on
vibratory
stimu-
lation
of
the
stapes
creates
an
interface
phenomenon
along
the
cochlear
duct,
known
as
the
Travelling
Bulge
(Bekesy).
Between
this
event
and
surf
on
sloping
beaches,
although
the
latter
is
a
surface
phenomenon,
exist
several
similari-
ties,
which
allow
for
an
analogy
in
principle
:
wavelength
is
gradually
lessened
("crowding")
and
amplitude
is
built
up
toward
a
maximum
(position
is
frequency
dependent)
beyond
which
it
declines
rather
steeply
;
also
eddies
are
formed.
Analysis
of
surf
as
the
more
tangible
of
the
two
phenomena
(especially
that
of
the
first
crests
of
a
steep
wave
front
arriving
at
a
slope)
indicates
that
surf
is
caused
by
interaction
of
two
events
:
(1)
"shallow-water"
opposition
and
(2)
reflection.
The
first
one
causes
a
slowdown
in
wave
velocity
with
subsequent
crowding
and
amplitude
buildup
;
these
in
turn
are
responsible
for
the
onset
of
eddying.
There-
after,
energy
dissipation
is
critically
increased,
causing
am-
plitude
to
decrease
again.—The
second
(reflection)
creates
a
shearing
effect
between
the
terminal
phase
of
one
wave
(wave
of
translation)
and
its
successor
;
thus,
by
accentuat-
ing
the
eddying
and
the
dissipation
of
energy,
surf
is
estab-
lished
as
a
confinement
in
space
of
eddying
waves.
J9.
Sonochemistry
and
the
Organ
of
Hearing.
Zmvxo
D.
ANGELUSCHEFF,
Hearing
Clinic,
City
Hospital,
New
York.—Modern
life
with
its
wailing
sirens,
screeching
cars,
blaring
radios,
TV,
and
roaring
jet
planes—all
carrying
high-
frequency
ultrasonic
spectra—is
potentially
dangerous.
Pro-
gressive
deafness
is
a
sequel
of
sonic-ultrasonic
(us)
impact
upon
the
organ
of
hearing.
Sonic
energy
as
a
mechanical
force
has
been
widely
explored.
The
chemical
aspect
of
the
problem
has
been
fully
neglected.
Chemical
reactions
on
the
biological
structures
of
the
labyrinth
can
be
initiated
by
infinitesimal
amounts
of
vibratory
energy.
The
electrokinetic
potentials
initiate
migration
of
ions.
If
the
impact
is
of
a
limited
capacity
and
duration,
the
response
of
the
organ
of
hearing
is
within
its
physiological
range,
the
damage
is
a
temporary
one,
and
reversible.
If
the
impact
is
sustained,
the
enhanced
damage
becomes
irreversible
and
progressive
fail-
ure
of
the
hearing
is
in
the
making.
The
ultrasonic
com-
ponents
of
sound
produce
an
intense
agitation
in
the
laby-
rinthine
fluid.
The
temperature
is
raised,
the
thermokinetic
effect
accelerates
the
rate
of
chemical
reaction.
As
ultraviolet
light
is
chemically
more
potent
than
the
visible
part
of
the
spectrum,
because
of
very
short
waves
and
greater
number
of
vibrations/second,
so
are
the
us
of
shorter
and
greater
number
of
waves—of
greater
penetrating
power—due
to
greater
absorptions.
us
permeates
the
bunched
particles
of
the
colloids,
disperses
them,
accelerates
the
rate
of
chemical
reaction,
and
advances
:
in
bone,
proliferation
of
new
bony
tissue
;
in
blood,
increase
of
Gamma
globulin,
fibrinogen,
hemolysis,
etc.
;
in
nerve,
eY'
of
potassium
ion
which
in-
hibits
and
paralyzes
nerve
function.
Session
K.
Physical
Acoustics
and
the
Solid
State
WARREN
P.
MASON,
Chairman
Invited
Papers
K1.
Measurement
of
Elastic
Stiffness
and
Dissipation
for
Solids
at
Ultrasonic
Frequen-
cies.
H.
J.
MCSKIMIN,
Bell
Telephone
Laboratories,
Inc.,
Murray
Hill,
New
Jersey.—A
review
is
made
of
different
experimental
techniques
for
measuring
the
dynamic
elastic
behavior
of
solids
at
frequencies
exceeding
20
kc/sec.
Because
of
time
limitations,
only
representative
(and
in
general
the
more
useful)
techniques
are
described
in
any
detail.
The
correlation
between
actual
quantities
measured
and
basic
properties
desired
is
discussed.
At
frequencies
between
20
and
500
kc/sec,
resonance,
water
immersion,
and
direct
transmission
techniques
are
of
greatest
interest.
For
frequencies
exceeding
500
kc/sec,
pulse
techniques
find
wide
application.
Methods
employing
phase
comparison
for
accurate
velocity
of
propagation
determination
are
stressed.
For
very
dissipative
materials
a
reflection
technique
is
described.
Illustrative
data
are
presented
for
several
of
the
methods
considered,
in
both
low-
and
high-frequency
ranges.
K2.
Recent
Developments
in
the
Use
of
Ultrasonic
Attenuation
Methods
in
Solid
State
Physics.
ROHN
TRUELL,
Division
of
Applied
Mathematics,
Brown
University,
Providence
12,
Rhode
Island.—This
is
a
discussion
of
general
methods
of
making
ultrasonic
attenuation
meas-
urements
in
the
megacycle
range
(5-500
Mc/sec
and
higher).
It
includes
some
discussion
of
dislocation
damping
effects
together
with
examples
where
ultrasonic
attenuation
measurements
have
led
to
new
information.
Work
has
been
done
on
metals
and
alloys,
semiconductors,
and
insulators
;
the
work
to
be
described
will
be
mainly
that
of
the
Metals
Research
Laboratory
at
Brown
University.