bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of the Threshold-of-Cavitation Noise in Liquid Helium
Authors: Finch R. D. , Wang Taylor G. J. , Kagiwada R. , Barmatz M. , Rudnick Isadore
Published: September 2005

Further studies of the threshold-of-cavitation noise in liquid helium have been made with an ultrasonic plane-wave system. The behavior of this threshold was found to have a similarity to that of the specific heat in the λ region. Both above and below the λ temperature, the threshold was very insensitive to variations of static pressure and unchanged by addition of solid air or the imposition of electric fields. These results are difficult to explain on the basis of conventional theories of nucleation, but possibly indicate that nucleation involves the aggregation of submicroscopic structures.
Weak Shocks in Solids
Authors: Harris Paul
Published: September 2005

The Burgers equation of fluid dynamics is applied to the problem of weak shock propagation in an anharmonic solid. For the crystalline solids KCl, Cu, and Ge, it is shown that the magnitude of A333333/G3333 is more than large enough to ensure steady compressive weak-shock propagation. For amorphous SiO2, however, A333333 is of such a sign that only weak steady rarefactions will form shocks.
Two-State Threshold Model and Rating-Scale Experiments
Authors: Broadbent D. E.
Published: September 2005

Reference is made to the assumptions necessary in order to test a two-state threshold model by an experiment using confidence ratings. It is argued that the testing of such a model by, a YES NO experiment also involves corresponding assumptions. If these are taken a justified, then the fact that both types of experiment have been shown to give similar values of false-alarm rate for a similar detection rate establishes that the appropriate assumption for an experiment with confidence ratings is justified. Consequently, either a two-state threshold model cannot be tested by either type of experiment or it is legitimately tested by both.
Design of a Perfectly Tracking Pickup Arm
Authors: Wouterlood H. J.
Published: September 2005

It is well known that all pickup arms that are commercially available show some tracking error, except for one or two points of the stylus path. A geometrical analysis is given of the conditions in which a stylus will track perfectly at each point of its path. The construction principle of such a pickup arm is briefly outlined.
Baffled Piston Radiator: Expansion of Potential in Far, Paraxial Field
Authors: Greenspan Martin
Published: September 2005

The potential of a circular source, having radially symmetrical but otherwise arbitrary distribution v(r0) of velocity over its face, is expanded as ψ = z −1e ikR(a0+a1z−1 + ⋯) [cylindrical coordinates (r,θ,z); center of source at r − z = 0]. We find a0 to depend only on the total volume velocity at the source. If v(r0) is known, all an can be calculated; if it is unknown, limits on an can be set.
Effect of Rough Boundaries on Normal-Mode Sound Propagation
Authors: Bucker H. P. , Morris Halcyon E.
Published: September 2005

Equations are derived for the calculation of first-order (scattering out of a mode)and second order (scattering into a mode) scattering corrections to the usual normal mode solutions. A simplified calculation illustrates the method and shows that, in special cases, sound scattering at the boundaries will cause significant changes in the propagating modes.
Fine Structure of Acoustic Fields Scattered from the Ocean Bottom
Authors: Hurdle Burton G.
Published: September 2005

Extending previously reported work [B. G. Hurdle, R. H. Ferris, and K. D. Flowers, “Effect of Transducer Velocity on the Structure of Signals Scattered from the Ocean Bottom,” J. Acoust. Soc. Am. 36, 1936–1942 (1964)], a method for describing the fine structure of acoustic fields scattered from the ocean bottom is presented. The fluctuating characteristic of scattered signals is shown to be the result of intercepting the lobes of the interference field when the source and or receiver are in motion. Lobe or interference widths computed from measured data are independent of speed and in good agreement with a simple physical model. Lobe widths also appear to be independent of bottom roughness. A similarity exists between acoustical scattering and optical scattering employing a monochromatic (laser) source.
Comments on “Harmonic Distortion of Spherical Sound Waves in Water” [O. H. McDaniel, J. Acoust. Soc. Am. 38, 644–647 (1965)]
Authors: Smith C. W. , Beyer Robert T.
Published: September 2005

Several points in a paper by McDaniel [J. Acoust. Soc. Am. 38, 644–647 (1966)] on finite-amplitude ultrasonic waves in water, have been questioned, and connections have been pointed out.
Tolerable Limit of Loudness: Its Clinical and Physiological Significance
Authors: Hood J. D. , Poole J. P.
Published: September 2005

In the normal-hearing subject, a sensation of unpleasant loudness is invariably associated with intensities of the order of 100 dB within the frequency range 500–4000 cps. This is referred to as the loudness-discomfort level (LDL). The intensity distribution of LDL has been established in a large group of subjects with unilateral end-organ deafness, in all of whom the presence of loudness recruitment had been verified by means of the alternate binaural loudness balancing procedure. In these, the distribution was similar to that of a normal-hearing group. By contrast, the LDL's of subjects with conductive or nerve-fibre deafness exceeded the maximum available audiometer intensity of 120 db. The test, therefore, is of particular value in establishing the presence or absence of loudness recruitment in bilateral deafness. These findings suggest a physiological limit of loudness perception, the theoretical implications of which are discussed.
Subharmonic Components in Cochlear-Microphonic Potentials
Authors: Dallos Peter J. , Linnell Craig O.
Published: September 2005

Microphonic potentials were recorded from the cochleas of guinea pigs and chinchillas. It was observed that with intense pure-tone stimuli, subharmonic potentials could be detected in the microphonic. These potentials possess high threshold (between 110 and 130 dB SPL), above which they immediately assume magnitudes that are commensurate with that of the fundamental. Increase in stimulus intensity above the threshold results in some increase in the magnitude of the undertones, but saturation and rapid decline follow within a 10- 15-dB range. The most frequent subharmonic appears at one half the driving frequency, but the quarter-frequency component is also common.
Finite-Difference Method for the Investigation of the Vibrations of Solids and the Evaluation of the Equivalent-Circuit Characteristics of Piezoelectric Resonators. III
Authors: Lloyd P. , Redwood M.
Published: September 2005

Part III: A finite-difference method [P. Lloyd and M. Redwood, J. Acoust. Soc. Am. 39, 346–361 (1966)] has been used to determine the resonant frequencies and vibration patterns of the first six contour modes of thin rectangular plates of Y-cut quartz. Predicted resonant frequencies are compared with experimental results for plates of various proportions; in most cases, the difference is less than 1%, even though relatively coarse grids are used in the finite-difference representation.
Analysis of Quadripole Methods for the Velocity of Sound
Authors: Romer I. C. , Gaggioli R. A. , El-Hakeem A. S.
Published: September 2005

A general analysis is presented of the systematic errors in phase-detection and amplitude-detection methods for establishing the velocity of sound propagated through gases confined in tubes.
Exact Solutions for the Propagation of Two Simple Acoustic Transients in Waveguides with Perfectly Reflecting Walls
Authors: Coppens A. B.
Published: September 2005

The response of a fluid-filled waveguide with perfectly rigid or pressure-release boundaries and uniform cross section to acoustic transients propagated down the axis of the guide is studied. Exact solutions are obtained for step-function and gated sine-wave excitations of the source. The particle velocity resulting from the latter input can be written as the sum of the familiar steady-state solution and a transient signal composed of two Lommel functions. An approximate expression is obtained that allows quantitative estimation of the behavior of the first portion of the transient as a function of the dimensionless parameter zλ/a2, where a is the radius of the waveguide, z is the distance that the transient has traveled, and λ is the free-field wavelength associated with the carrier frequency of the gated sine wave. Some experimental confirmations of the predicted waveforms are presented. The relevence of these propagation effects on the accuracy of velocimeters is discussed.
Acoustic Radiation from a Wobbling Piston
Authors: Mangulis Visvaldis
Published: September 2005

The sound field of a circular piston in an infinite rigid plane baffle is calculated when the motion of the piston consists of the conventional uniform velocity normal to the plane of the piston plus a wobbling motion about a diameter of the circle: as an axis. There is a net resultant moment owing to the wobble; this moment is proportional to an integral of the square of the farfield pattern function over real and imaginary angles. A wobble impedance is defined as the moment divided by the angular velocity of the wobble. The real part of the wobble impedance is obtained from the integral of the square of the farfield pressure over real angles, and the imaginary part is obtained from the real part by the use of the Kramers-Kronig, or dispersion relations. Numerical results for the wobble impedance are presented. It is shown that for small pistons a merely wobbling piston is less efficient as a generator of sound than the customary uniform-velocity piston.
Method of Calculation of Frequencies of Partially Fixed Beams Carrying Masses
Authors: Amba-Rao Chintakindi L.
Published: September 2005

In this paper, a convenient method is presented for obtaining a closed-form (not series) solution for solving the problem of free vibrations of a partially fixed beam, with unequal end fixities, and carrying an arbitrary number of concentrated masses in an arbitrary way. The method utilizes finite Fourier sine transforms. By this method, the simplified frequency equations to a general case and two special cases are given. The eigenfrequencies of a partially fixed beam (equal end fixities) with a mass in the middle and at quarter-span are evaluated numerically; and the results of the former are compared with those of an earlier publication, where the classical method is utilized.
Flexural Vibrations of a Circular Ring when Transverse Shear and Rotary Inertia are Considered
Authors: Bakshi Jagjit Singh , Callahan W. R.
Published: September 2005

The partial-differential equations derived by Reissner, Uflyand, and Mindlin governing the motions of plates are solved for a plate bounded by circular contours and radial lines. Two cases have to be considered. They are: Case I: a plate bounded by circular contours and radial lines (r = r1, r = r2, r2 > r1; θ = θ1, θ = θ2); Case II: a plate bounded by two concentric circles (r = r1, r = r2, r2 > r1 … circular ring). The solution for each partial-differential equation is an infinite series of product solutions. Case I cannot be solved by product solutions because of the impossibility of satisfying boundary conditions along the radial lines θ = θ1 and θ = θ2. Case II is solved for each of the eight different boundary conditions entering into this theory for each eigenvalue m = 0, 1, 2, … Hence, after the elimination of the arbritrary constants for m = 0, 1, 2, …, the frequency equation for each problem is obtained by solving a determinant of sixth order equated to zero. A comparison between the classical theory and the present theory, which includes coupling between flexural and shear motions, for the case of the clamped circular ring is included.
Coupled Vibratory-System Analysis, Using the Dual Formulation
Authors: Karnopp Dean
Published: September 2005

Principles by means of which an arbitrary vibrational system may be cut into subsystems and described by coupled modal equations are exposed and illustrated with an elementary example. The symmetry of the equations attainable when both the usual geometric description and the dual or force space representation are used is shown. The difficulties in use and interpretation of the coupled equations when the coupling is not weak are discussed.
Use of Instantaneous Axes for Determining Small Oscillations
Authors: Sweet A. L. , Genin Joseph
Published: September 2005

A theorem is presented and proved that establishes points about which the equation of angular momentum simplifies for small (linear) oscillations of a rigid body. Thus, a fourth criterion in addition to the well-known three conditions of classical mechanics is established. An illustrative example is given.
Analysis of Electroacoustical Transducers by Differential Immittance Techniques
Authors: Dranetz Abraham I. , Rathbun Harvey
Published: September 2005

Techniques are in use for the measurement and recording of the impedance and admittance loci of electroacoustical transducers at various levels of input power. The resulting data are used for determining properties such as piezoelectric coefficients, mechanical Q, resonant frequency, potential efficiency, etc. An extension of these techniques has now been developed to provide direct measurements and graphic recordings of the difference between two admittances or impedances. This approach may be used to separate the motional impedance or admittance circle from the complete locus without the need for lengthy arithmetical manipulations and also to read the minor component of impedance or admittance with greater accuracy than has heretofore been possible in direct-reading systems. This approach has also been applied to the measurement of the dielectric loss and capacitance of piezoelectrics under high voltage and to the separation of time-variant components of impedance from time-invariant components.
Acoustic Scattering from Fluid Spheres
Authors: Frey H. G. , Goodman R. R.
Published: September 2005

The problem of scattering of sound from fluid spheres is investigated for the case where the acoustical properties of the sphere and surrounding medium are very similar. This similiarity allows Bessel functions with arguments related to acoustic properties inside the sphere to be expressed in series expansions of Bessel functions, with arguments related to the acoustic properties outside the sphere. Using only the fiirst-order terms in the expansions results in simpler solutions than the exact case for plane-wave conditions in the backscattered direction. The amplitudes and time dependences for backscattered acoustic pulses can then be calculated to first order in the differences in density and bulk modulus of the two media. Higher order terms are very complicated, and a convenient way of determining the time dependences of these terms has yet to be obtained.
Binaural Unmasking of Complex Signals
Authors: Flanagan J. L. , Watson B. J.
Published: September 2005

Binaural masked thresholds were measured for periodic 100-μsec rectangular pulses of period T. Signal parameters were pulse rate (10, 50, 100, 250, and 1000 pps), interaural phase difference (0 and π rad), and interaural time difference (0–5 msec). Spectral content of the signal was controlled by addition or subtraction of phase-locked harmonic components and by high-pass and low pass filtering (cutoff frequencies 300, 600, 1200, and 2400 cps). Broad-band, interaurally in-phase, masking noise at 60 dB sensation level was used throughout. The signals were transduced by headphones, and the masked thresholds were determined by a modified Békésy technique. The difference between the threshold for a given test condition and threshold for the signal in-phase condition is defined as the masking-level difference (MLD), or the binaural release from masking. For all pulse rates, maximum release from masking obtains for an interaural time of 1.5 msec or T/2, whichever is smaller. The greatest binaural unmasking occurs for a pulse rate of 250 pps and is less at higher and lower rates. For all tonal cases (pulse rates of 250 pps and higher) the release from masking is found to relate primarily to the fundamental component. Elimination of the fundamental substantially reduces the MLD. At the lowest pulse rate, high pass filtering of the signal also reduces the MLD to a small value. The largest MLD's are found for signal conditions that give rise to basilar-membrane motion near the 300-cps place and that lead to interaural time differences of about 1.5 msec in the neural activity originating from these places. The same interaural disparity at higher-frequency places produces substantially smaller MLD's. The MLD therefore appears specific to membrane place as well as to interaural time difference.
Temporary Threshold Shift in Males and Females
Authors: Ward W. Dixon
Published: September 2005

Various measurements of temporary threshold shift (TTS) from high-intensity tones and noises were made on 24 male and 25 female young normal-hearing adults. Significantly more TTS was produced in males by low-frequency stimuli (below 1000 cps) and significantly less by high-frequency stimuli (above 2800 cps). No differences between sexes in TTS from low intensities (40 dB SL), in auditory adaptation (perstimulatory fatigue at 1000 cps), in rate of recovery from a fixed value of TTS, or in TTS produced by impulse noise could be demonstrated. It is suggested that these results all imply that males and females do not differ in intrinsic fragility of sensory structures on the basilar membrane, but that women have more efficient middle-ear muscles than men.
Measurement of the Room-Temperature Microwave Ultrasonic Attenuation of Z-Cut Quartz by Brillouin Scattering of Light
Authors: Wilkinson C. D. W. , Caddes D. E.
Published: September 2005

The advantages of Brillouin scattering of light by injected sound as a way to measure attenuation and other acoustic-beam parameters in transparent solids are discussed. Room-temperature microwave frequency measurements on a sample of Z cut quartz are given.
Mapping of the Space-Time Correlation of Ambient Sea Noise
Authors: Arase Elizabeth M. , Arase T.
Published: September 2005

The space-time correlation of ambient noise in the ocean was measured with vertical elements at a depth of 14 500 ft at 800 Hz and sea state 6. These data are presented in the form of a map, showing the principal maximum and zero axis crossings for comparison with recent theoretical work.
Impulse Propagation in Underwater Sound Channels
Authors: Mellen Robert H.
Published: September 2005

Long-range propagation in the Artic Ocean is characterized by a half- channel with surface scattering. Since the signal from an explosion suffers both multipath dispersion and loss of high frequencies, a normal-mode description is indicated. However, scattering loss is expressed in terms of grazing angle and number of surface reflections; thus, a ray description is also useful. A simple asymptotic connection between normal modes and rays (linear profile) shows that, for each successive ray arrival, after the first, the phases of the component frequencies shift −π/2 effectively. In a symmetrical sound channel, the effective phase shifts are π, 2.
Complementarity of Sound Buildup and Decay
Authors: Schroeder M. R.
Published: September 2005

Sound buildup and decay in an enclosure are shown to be complementary. A simple sound-decay meter, based on this complementarity, is described. Jordan's measure of “steepness” of the sound buildup is shown to equal the amplitude of the squared-impulse response at a fixed delay (typically 40 msec).
Descriptive Analysis of Doppler Discrimination as a Function of Variations in Dimensions of the Sonar Echo
Authors: Lau Alan W.
Published: September 2005

Subjects were drilled and tested on their ability to judge sonar Doppler. Synthetic sonar echoes were systematically varied with respect to type of Doppler, echo duration, the rate of echo onset, and relative signal strength, and superimposed upon a sea-recorded reverberation pattern. The purposes of the study were to (1) identify the effects that variations in echo length, echo onset, and relative signal strength have upon the ability to discriminate Doppler correctly; and (2) evaluate the effect that training has upon the improvement of Doppler discrimination. Results indicated that performance was significantly improved by training. Although Doppler discrimination was significantly affected by echo duration and the relative intensity of the echo, the interactions among the echo dimensions appeared to be largely the result of various perceptual or response biases toward no Doppler echoes.
Width of the Spectrum Effective in the Binaural Release of Masking
Authors: Sondhi Man Mohan , Guttman Newman
Published: September 2005

In an experiment concerned with the binaural masking-level difference phenomenon, an attempt was made to determine the extent of the masker spectrum effective in the release of masking. The experiment utilized a uniform power-spectrum noise separated into two bands differing in interaural phase—an “inner” band surrounding the test signal and “outer” band. Binaural masking-level differences (BMLD's) were traced as functions of the interaural signal phase (0 and π rad), the relative phase of the bands (0 and π rad), and the bandwidth of the inner band. It was found that a narrow inner band homophasic with respect to signal phase could destroy much of the release of masking owing to the heterophasic outer band. The converse was not true: a wide heterophasic band (125 and 200 cps centered at 250 and 500 cps, respectively) was required to produce significant release. These results depart significantly from predictions of the equalization—cancellation theory of binaural masking and furthermore do not support an assumption that BMLD is a function of the interaural noise crosscorrelation coefficient only.
Basis for the Design of a Circumaural Earphone Suitable for MAP Determinations
Authors: Atherley G. R. C. , Lord P. , Walker J. G.
Published: September 2005

A source of error using supraaural earphones in the determination of auditory thresholds appears, in part, to be associated with the changes in position of the earphone relative to the ear. The authors have investigated the possibility of constructing a circumaural device that will reduce this error. The design is based on a study of the standing-wave modes that occur in the cavity. The reduction of these by means of a double-cavity system and suitable damping material strategically positioned is discussed. Experimental results are reported that show that displacement sideways of this circumaural earphone on a flat-plate coupler by as much as 1.25 cm from the central position produces a variation in response of only 1 dB up to 6 kcps and 6 dB between 6 and 8 kcps.
New Correlation Vocoder
Authors: Christiansen H. M. , Schweizer L. , Séthy A. , Hoffenreich F.
Published: September 2005

A correlation vocoder is described that uses delay lines composed of simple all-pass RC or RLC sections. The synthesizer of the correlation vocoder is represented as a time variable filter whose response is controlled by the “channel signals” derived in the analyzer. It is shown that the all-pass delay line, having a phase delay that decreases with increasing frequency, gives the vocoder a spectral resolution better adapted to the properties of speech than does a delay line with constant delay. In particular, when RLC sections are used, the spectral resolution approximates that of a spectrum-channel vocoder. Results of a quality test are given. An “opinion scale” was used that rates the subjective quality between zero (bad) and four (excellent). An experimental RLC vocoder received a rating of 1.35 for male speech as compared to 1.55 for a typical spectrum-channel vocoder and 1.75 for ordinary telephone speech.
High-Speed Sound Spectrograph
Authors: Presti A. J.
Published: September 2005

A new sound spectrograph is described that incorporates many new and unique automatic features. The mechanical assembly includes a tape-handling system for continuous record and playback. An integral part of the mechanical assembly is a tape scanner and marking drum. The scanner can repeatedly scan any 2.4-sec segment of tape for spectrographic analysis, and the tape may be automatically advanced in sequence for analysis of continuous segments of the recording. A high speedup ratio enables a spectrogram to be made in 80 sec. Three basic types of spectrograms can be made: (1) the normal display of time versus frequency with intensity shown as blackness; (2) an amplitude-contour display; and (3) a cross-sectional amplitude display.
Implementation of a Pitch Extractor of the Double-Spectrum-Analysis Type
Authors: Weiss Mark R. , Vogel Reinhold P. , Harris Cyril M.
Published: September 2005

A new technique of pitch extraction has been implemented that makes use of the double spectrum analysis of speech signals. In contrast to previous applications of this method of extracting pitch, the system described here operates in real time, it does not require the use of a computer, important system parameters such as “processing period” can be changed manually or adaptively, and the use of logarithmic compression is optional. When logarithmic compression is employed, the pitch extractor represents a real-time implementation of the “cepstrum” technique. The performance characteristics are described and illustrated for practical field conditions, including poor signal-to-noise ratios.
Scattering by an Array of Cylinders as a Function of Surface Impedance
Authors: Embleton T. F. W.
Published: September 2005

Plane waves are considered impinging at normal incidence on a half-space (or slab of considerable thickness) containing a random array of cylinders. The average attenuation per unit distance within the array is evaluated numerically for various sizes of scatterers, radius a = 0.1–10 cm, concentrations 10−5−3×10−3 cm−2, and surface impedance from 0 to ∝. It is found that attenuation is exactly proportional to radius and approximately proportional to concentration over these ranges of parameters. As a function of stiffness reactance and ka (k being the wavenumber of the incident sound field), the attenuation becomes infinite at the origin of the ka, X/ρc plane, but is otherwise zero when ka = 0; elsewhere, the function is a series of ridges radiating from the vicinity of the origin these ridges are sharp and high close to the origin, becoming broader and lower further away; each ridge is curved, being convex to the ka axis. For any given value of stiffness reactance, X/ρc, the greatest attenuation is found at frequencies near the value given by ka = X/ρc. When X/ρc is a mass reactance, no interesting features arise and the surface is a gently sloping plateau.
Vibrations of Rectangular Sandwich (Honeycomb) Plates with Mass Attachment
Authors: Jacobson M. J. , Malakoff J. L. , Preston J. L. , Weingarten V. I.
Published: September 2005

Mass attachments may significantly alter the natural frequencies and response characteristics of rectangular honeycomb sandwich plates. Based on the well-known analyses of Mindlin [J. Appl. Mech. 18, 31–38 (1951)] and Reissner [NACA Tech. Note TN 1832 (1949)], a vibration theory is developed for sandwich plates. The effect of mass attachments on natural frequencies and associated modal shapes is obtained. A linear, elastic, small-deflection theory with core shear effects is presented. Computer results and experimental results are reported.
Sea-Surface Roughness and Acoustic Reverberation—An Operational Model
Authors: Martin J. J.
Published: September 2005

Underwater acoustic reverberation from the sea surface appears to be a combination of specular reflections and diffuse scattering, which may include, on an experimental basis, the effects of subsurface volume reverberation. This paper (1) separates these contributions as a function of incidence angle, radiation wavenumber (frequency), and sea-surface wind speed; (2) shows the fundamental relationship between specular reflections and diffuse scattering; (3) develops a tentative spectrum of roughness at large wavenumbers for a developing sea surface; (4) points out various radiation-wavenumber, incidence-angle and wind-speed régimes associated with sea-surface returns; and (5) presents a correlation formula for acoustic reverberation from a sea surface, which is applicable as well to forwardscattering of both sound and radar waves. The results of the paper are familiar in the sense that no new mechanism for reverberation is invoked and novel in the sense that the familiar mechanisms are used to interpret acoustic, turbulence, and hydrodynamic data in a manner that predicts sea-surface acoustic reverberation in a physically consistent way.
Low-Frequency Sound Radiation from Slender Bodies of Revolution
Authors: Pond Hartley L.
Published: September 2005

The radiated pressure field due to the low-frequency vibration of a slender body of revolution is expressed in terms of a distribution of sources and doublets along the body axis. The strength of the singularities is determined from an analysis of the flow near the slender body. For axially symmetric flow, a longitudinal rigid-body vibration and a simple type of accordion vibration are considered. For these examples, the source distribution has the dominant effect on the farfield pressure. For transverse vibration, there is only a doublet distribution. The strength of the doublet distribution depends on the force that the body exerts on the fluid. For wavelengths much greater than the maximum body diameter, this force can be conveniently determined by the extended Lagally theorem of incompressible hydrodynamics. Formulas for the farfield pressure for each type of vibration are given for spheroids and a simple class of streamlined bodies. Examples illustrating the effect of change in body shape and type of vibration are given.
Standard Reference Pressure for Underwater Sound
Authors: Batchelder Laurence
Published: September 2005

The choice of a standard reference pressure for sound in water should be decided by workers in underwater acoustics, and not forced upon them by committees that do not adequately represent their interests.
Response of Viscoelastic Cylindrical Shells to Moving Loads
Authors: Tang Sing-Chih
Published: September 2005

This paper presents the steady-state response of infinite-length shells of linear viscoelastic materials to moving axisymmetric ring loads based on the shell theory with corrections for the shear-deformation and rotatory inertia effects. The complex Fourier transform is used to obtain the exact solution. Numerical results for shells of Maxwell materials with various viscous damping coefficients under various velocities of moving loads are given. The special case, response for elastic shells, is also discussed.
Sloshing of a Liquid in Connected Cylindrical Tanks Owing to U-Tube Free Oscillations
Authors: Yeh Gordon C. K.
Published: September 2005

When two parallel cylindrical tanks are connected by a pipe joining the tank bottoms, the liquid can oscillate back and forth between tanks, just as in a U shaped tube. This paper deals with the axisymmetric sloshing oscillations excited in each tank because of the flow back and forth between the tanks. By applying the results from a recent paper [P. G. Bhuta and G. C. K. Yeh, “Liquid Sloshing Due to a Time Dependent Discontinuous Boundary,” Intern. J. Mech. Sci. 7, 475–488 (1965)], the expressions of velocity, pressure, and waveheight are obtained in terms of the liquid density, tank dimensions, pipe radius, and U-tube natural frequency, which, in turn, is a function of the tank dimensions, pipe dimensions, and the magnitude of acceleration vector. Resonance will occur whenever the U-tube natural frequency is equal to any one value of the natural frequencies for the axisymmetric sloshing modes of the liquid in each cylindrical tank. Pertinent dimensions to be avoided are pointed out. Extension of the results to asymmetric sloshing based on a paper by Yeh [“Liquid Sloshing in a Moving Tank with a Time Dependent Discontinuous Boundary,” TRW Space Technol. Labs. Rept. EM 14-12 (6438-6002 RU-000) (June 1964)] is also indicated.
Analog-Computer Program for Studying Underwater Sound Rays and Refraction Effects
Authors: Beam John P.
Published: September 2005

An analog-computer program has been developed that traces sound rays and gives a continuous value for the refractive anomaly. The program uses the second derivative of the sound velocity with respect to depth as a description of the medium through which sound waves travel. Tests have been made using constant values for the second derivative. Excellent agreement has been obtained between computer results and mathematical results predicted by theory.
Transmission of Random Sound and Vibration through a Rectangular Double Wall
Authors: White Pritchard H. , Powell Alan
Published: September 2005

The existence of many modes of vibration in a complex system makes a detailed classical analysis almost intractable. However, when excited by broad-band random noise, the detailed response characteristics may be overlooked and statistical properties such as mean-square values and power spectra provide a measure of the vibration. The existence of classes of similarly excited modes allows theories of room acoustics and thermodynamics to be applied successfully. For sound transmission through a rectangular double wall, this technique gives results that agree within experimental error of measured transmission loss, much better than do conventional loss estimates. Both theory and experiment confirm that the product of modal density, average joint acceptance of the first panel, and the ratio of radiation to total resistance of the second panel are the most important characteristics in determining the transmission characteristics of the wall.
Experimental Study of the Fundamental-Frequency Component of a Plane, Finite-Amplitude Wave
Authors: Lester William W.
Published: September 2005

The fundamental-frequency component of a plane, finite-amplitude wave is measured in water at 5.65 Mcps by a fixed-distance pulse method giving variable-distance results. The absorption coefficient of the fundamental-frequency component of the wave is examined from the standpoint of its maximum, average, and instantaneous values. It is found that there is a maximum amount of sound-pressure amplitude that can be transmitted over a fixed path, varying as the −0.80 power of the distance. A value for the nonlinearity parameter of water is obtained, giving B/A = 6.3±0.8.
Relation between Third-Order Elastic Moduli and the Thermal Attenuation of Ultrasonic Waves in Nonconducting and Metallic Crystals
Authors: Mason Warren P. , Bateman T. B.
Published: September 2005

The background loss of all materials, and sometimes the principal loss in single crystals, is connected with the conversion of acoustic waves into thermal phonons. One source of conversion is the thermoelastic loss resulting from the flow of heat from the compressed (hotter) part of the wave to the expanded (cooler) part. This source accounts for about half the thermal attenuation in a metal, but only about 4% of that in an insulator. Another source of thermal attenuation—first suggested by Akhieser—is connected with the separation of phonon-mode temperatures by a suddenly applied stress, followed by an equilibration of these temperatures with a relaxation time τ. This source has been called “phonon viscosity.” A method for evaluating this source of attenuation was proposed in previous papers [W. P. Mason and T. B. Bateman, J. Acoust. Soc. Am. 36, 644–652 (1964); W. P. Mason, Physical Acoustics (Academic Press Inc., New York, 1965), Vol. 3B, Chap. VI, pp. 235–286]. It involves the use of the third-order elastic moduli to determine the energy stored by the phonon-mode temperature separations, together with a relaxation time τ to equilibrate this energy. Recently, new determinations of these third-order moduli have been made for NaCl, KCl, MgO, and Y3Fe5O12 (YIG). The present paper shows that the formulas predict the measured attenuations (longitudinal and shear waves) within about 25%. Silicon, without oxygen, has a higher thermal conductivity than silicon with dissolved oxygen. This is reflected in the higher attenuation of oxygen-free material, in agreement with theory. A theoretical evaluation of the attenuation is made for a longitudinal wave propagated along a (111) axis. For metals, it is shown that the “phonon-viscosity” attenuation is in the same order as thermoelastic attenuation. A method for evaluating this loss in single-crystal lead is devised. The attenuation measured over a temperature range is consistent with the sum of the thermoelastic attenuation and the “phonon-viscosity” attenuation.
Acoustic Experiment to Determine the Composition of an Unknown Planetary Atmosphere
Authors: Hanel R. A. , Strange M. G.
Published: September 2005

Measurement of the speed of sound and the acoustic impedance, combined with a knowledge of ambient pressure and temperature, provide sufficient data for determining the relative abundance of constituents in a mixture of nitrogen, argon, and carbon dioxide. Sound absorption and dispersion yield additional information for checking the consistency of the results. An instrument has been developed to measure the acoustic properties of an unknown gas mixture. Laboratory results demonstrate the feasibility of determining the gas composition within a few percent. The technique of velocity measurement by use of phase comparison over several wavelengths is quite sensitive and may be useful in other applications.
Energy Density of Sound in a Dispersive Medium
Authors: Smith W. E.
Published: September 2005

The linearized field equations are written with phenomenological frequency-dependent parameters to describe dispersion, in a manner analogous to the use of frequency dependent permittivities and permeabilities in electromagnetism. It is then shown that the energy density for such a medium should include contributions from the frequency derivatives of these parameters.
Transformation of the Helmholtz Integral into a Line Integral
Authors: Lindemann Oscar A.
Published: September 2005

The quadruple Helmholtz integral, which appears in the expression for the radiation impedance of a piston in a plane baffle, can be very simply transformed into a double contour integral. This can simplify computation, particularly in the case of a rectangular piston.
Effects of Heat and Ultrasound on Vx-2 Carcinoma in Bones of Rabbits: A Preliminary Report
Authors: Cerino Lawrence E. , Ackerman Eugene , Janes Joseph M.
Published: September 2005

The present series of experiments was undertaken in an effort to delineate those aspects of ultrasonic irradiation that might be destructive to malignant tumors of bone. The experiments were performed on rabbits having Vx-2 carcinoma implanted within the tibias. In preliminary, experiments, it was shown that the destructive effect of ultrasound on normal bone and on the circulation through normal bone was probably primarily due to heat. In the current series of experiments, it was shown that the heating of the bone was critically dependent on the exact location of the focus of the ultrasonic transducer within the rabbit leg. Our experiments suggested that (1) exposure of Vx-2 carcinoma to a temperature of 50°C for at least 10 min is sufficient to destroy the transmissible characteristics of this tumor, (2) exposure of Vx-2 carcinoma to ultrasonic fields with intense cavitation (applied in the absence of heat) has an effect that is far less than that of heating to 50°C for 10 min, and (3) controlled ultrasonic heating can increase the temperature of a bone to levels sufficient to destroy tumor growth within the bone.
Energy Exchange between Incompressible Near and Acoustic Far Field for Transient Sources
Authors: Junger Miguel C.
Published: September 2005

The work Ws, performed on the fluid medium by a transient source to whose boundary has been imparted a step velocity V is shown to equal twice the acoustic energy radiated to the farfield in the form of a compressional wave, whatever the source configuration. The other half of Ws constitutes the kinetic energy in the incompressible nearfield of the source and, when written in the form 12MaV2, can be computed from the accession to inertia Ma associated with the steady-state low-frequency reactive radiation loading. If the source boundaries are brought abruptly to a standstill, the kinetic energy stored in the incompressible nearfield is transformed into acoustic energy radiated to the farfield as a rarefaction wave, no additional work being performed by the source. If the source boundaries are accelerated gradually (or if the sound velocity is allowed to become arbitrarily large), the work done by the source tends to one-half the work associated with a velocity step, no acoustic energy being generated. If the source boundary is gradually decelerated, the nearfield kinetic energy is converted into work done by the fluid on the source instead of being radiated to the farfield as a rarefaction wave.
Influence of Fluid Loading on the Radiation from Infinite Plates below the Critical Frequency
Authors: Maidanik G. , Kerwin E. M.
Published: September 2005

Fluid loading influences the total acoustic power and the directivity of the radiation from a large, flat plate driven by localized forces. The frequency range considered here is that below the “critical” frequency. In this range, the in vacuo speed of plate flexural waves is less than the speed of sound in the adjacent fluid medium. For a point force, the directivity of the radiation field is that of a monopole for light fluid loading, but changes to that of a dipole for heavy fluid loading. Analogous behavior occurs in the case of a line force. An equivalent acoustic-dipole source can be specified, and one can apply this equivalent-source formalism to calculate the power radiated by point- and line-moment excitations under conditions of heavy fluid loading. The radiated power for a point-moment excitation computed by this approach agrees with the earlier results of Thompson and Rattayya. [J. Acoust. Soc. Am. 36, 1488–1490 (1964)].
In-Plane Inextensional Vibrations of a Circular Ring with a Time-Dependent Displacement Prescribed at the Boundaries
Authors: Clayton M. H. , Royster L. H.
Published: September 2005

A solution is obtained for the problem of an incomplete ring clamped at each end and given a prescribed, time dependent displacement at the boundaries. Only the in-plane inextensional vibrations are considered. Natural frequencies and modes are found for central angles between 0° and 180°.
Vibrations of Circular Cylindrical Shells of Piezoelectric Silver Iodide Crystals
Authors: Paul H. S.
Published: September 2005

Solutions for the flexural and axisymmetric vibrations of piezoelectric cylindrical shells of the crystal class 6mm are investigated. Applying suitable mechanical and electrical boundary conditions, the frequency equations have been obtained.
Acoustic Radiation from a Piston in a Layered Medium, with Applications to a Layer Containing Bubbles
Authors: Mangulis V.
Published: September 2005

The radiation self-impedance, the mutual coupling coefficient, and the farfield radiation pattern of a circular piston in an infinite rigid-plane baffle is obtained when the acoustic medium in front of the piston and baffle consists of a layer followed by an infinite half-space with different properties. Numerical calculations are presented for cases where the half-space is ordinary water and the layer is water containing resonant air bubbles. The properties of water containing bubbles are discussed. The Green's function for a layered medium is derived. The reciprocity theorem for a layered medium is proved.
Correlative Properties of Ambient Noise at Bermuda
Authors: Urick R. J.
Published: September 2005

Time-delay correlograms have been obtained in two frequency bands over a range of wind speeds and hydrophone separations, using the 40-element vertical array at Bermuda. The correlograms are of two different types, suggesting a different origin of the ambient noise under different conditions of wind and frequency band. One type shows high noise coherence at 0 time delay for all separations; it occurs at low wind speeds in the low-frequency band and indicates horizontally arriving noise. The other type is less coherent, with a correlogram peak at a time delay that changes with separation; it occurs at high wind speeds in the high-frequency band and suggests noise of sea-surface orion. These findings are consistent with the results of other investigations of the noise at Bermuda. The correlograms are useful for the prediction of the gain to be expected from a vertical array steered at any angle to the vertical. A simple example is worked out by way of illustration.
Effective Coupling Factor of Single-Degree-of-Freedom Transducers
Authors: Woollett R. S.
Published: September 2005

The effective electromechanical coupling factor is widely used by practical transducer designers as an index of performance potential in evaluating new or proposed transducers. However, the properties of the effective coupling factor and its associated formulas do not appear to be well documented even for simple transducers. In an attempt to correct this situation, tables of formulas are presented here for the effective coupling factor in terms of equivalent-circuit parameters and in terms of measured immittance data. The treatment is restricted to lumped-parameter transducers with negligible electric or magnetic dissipation. The significance of the effective coupling factor as an indicator of the limits of physical realizability is illustrated by the instability occurring in electrostatic, variable-reluctance, and moving-coil transducers. Many influences conspire to degrade the effective coupling factor to a lower value than the intrinsic coupling factor of the active material incorporated in the transducer structure. Examples are leakage inductance and eddy-current shielding in magnetostrictive transducers, and stiffness augmentation of a simple resonator by its auxiliary structure. The stiffness of a liquid-filled cavity has a degrading effect even when the cavity is self-resonant. Whenever an extended transducer circuit can be reduced to single-degree-of freedom form, the effective coupling factor will serve as a powerful tool for quickly revealing possible deterioration in performance resulting from the circuit additions.
Mechanical Impact: A Model for Auditory Excitation and Fatigue
Authors: Crane H. D.
Published: September 2005

An auditory model is developed in which hair cell excitation is based on mechanical impact of the cochlear hairs against the tectorial membrane, and auditory fatigue is based on a relatively slow mechanical bending of the tectoral membrane to conform to the deflection envelope. In this model, the cochlear system is treated basically as a spatially distributed, mechanical, envelope-detection system. Some novel mechanical vibration and impact devices that led to the development of this picture of hair-cell excitation are discussed. It is shown that the model can explain, and is consistent with, a relatively wide range of auditory data such as pitch and threshold shifts with pure tone fatigue, modulation of a steady high-frequency tone by a simultaneous low-frequency tone, and very rapid high-frequency cutoff in “tuning curves” recorded from single auditory fibers. The model leads to a reinterpretation of such features as pitch sharpening, missing fundamentals, and fatigue. No new data are presented, although new experiments are suggested by the model.