bluuebunny/crossref_metadata_2025 huggingface dataset:
Time Variability of Volume Scattering a Small Oceanic Area
Authors: Gold Barry A. , Van Schuyler Peter
Published: September 2005

Volume-scattering strengths are presented for both daytime and nighttime, measured at three different times, in the same oceanic area during a nine-month period. The data are analyzed in 13-oct bands covering the frequency region from 2.5 to 20.0 kHz. The maximum and minimum variation in scattering strengths over the nine-month period range from 11 to 3 dB. Swimbladder volumes of fishes are determined from the acoustic characteristics of deep scattering layers. A volume of 0.72 cm3 is computed for fish residing at 950 m and 0.022 cm3 for fish at 610 m. Biological sampling of the deep-scattering layers shows the presence of four families of fishes that possess swimbladders: Myctophidae, Gonostomatidae, Sternoptychidae, and Melamphaidae.
Acoustic-Impedance Measurements at High Hydrostatic Pressures
Authors: Sabin Gerald A.
Published: September 2005

The theory, design, and operation of a system for the measurement of acoustic impedance at hydrostatic pressures to 10 000 psig are described. The system is a pulse tube featuring the use of coherent pulses. The acoustical characteristics of materials are determined from measurements made on small samples (2 in. diam × ∼ 6 in. long). Three different measurement methods are discussed.
Measurement of Specific Acoustic Impedance
Authors: Rogers Joseph Wood
Published: September 2005

The theory of an experimental procedure that can be used to measure specific acoustic impedance is presented in this paper. No moving parts are required. Only two measurements need be made. A sequence of simple calculations is presented for reduction of these data.
Axisymmetric Plane-Strain Vibrations of a Thick-Layered Orthotropic Cylindrical Shell
Authors: Ahmed Nazeer
Published: September 2005

The axisymmetric plane-strain vibrations of a thick-layered orthotropic cylindrical shell are analyzed, using a generalized Fourier-series technique that allows the determination of the frequencies and vibration modes of the composite shell in terms of those of the individual layers. These vibration modes are used to study the forced vibrations of such a shell subjected to an internal harmonic pressure. Numerical results are presented for a two-layered orthotropic cylindrical shell.
Scattering of Acoustic Waves by a Penetrable Sphere with Statistically Corrugated Surface
Authors: Chen Yung Ming , Kim Sung Jin
Published: September 2005

The scattering of time-harmonic spherical acoustic waves by a penetrable sphere with statistically irregular surface has been studied. The first and the second moments of the potential fields are computed. The asymptotic expressions of the moments of the fields for a small corrugated sphere are also derived. For the purpose of illustration, a simple example, a small corrugated sphere of radius, a, with its mean surface defined by 〈r̃〉 = a(1 + ε sinθ + ε cosθ sinφ), is considered and the far field scattering amplitude of its second moment is calculated and plotted.
Optimum Lengths of Valve Tubes for Brass Wind Instruments
Authors: Young Robert W.
Published: September 2005

A difficulty in the design of brass wind instruments arises from use of the valves both singly and in combination. A single valve tube that lowers the frequency the proper fractional amount lowers the frequency a lesser fractional amount when it is added to the main tube already lengthened by another valve tube. From a trial-and-error study, J. Redfield [J. Acoust. Soc. Am. 3, 292–296 (1931)] proposed that the tones produced separately by the second, first, and third valves, respectively, be tuned 12, 16, and 21 cents flat. The present paper shows how the discrepancies can be minimized efficiently by the method of least squares, and in a way best suited to a given instrument. For cornets and trumpets played at normal room temperature, a good compromise can be attained by making “open” tones 1 cent sharp, and those produced by the second, first, and third valves, respectively, 0, 6, and 18 cents flat. With such tuning, the two tones that must be obtained by the three valves in combination are likely to be not more than 20 cents sharp on the average; this result is related to the fact that valve tubes are not ordinarily used continuously and so are not up to equilibrium temperature. For baritone and bass horns that are not warmed by the breath to any appreciable degree, a good compromise is attained by tuning the open tones 1 cent sharp on the average, the second-valve tones at zero deviation, the first-valve tones 7 cents flat and the third-valve tones 25 cents flat.
Experimental Evaluation of the Total-Reflection Method of Determining Ultrasonic Velocity
Authors: Fountain Lewis S.
Published: September 2005

Ultrasonic velocities in a solid can be determined by finding the incident angle of a beam at a liquid-solid interface that produces maximum reflection in the liquid. Experiments were performed to find the accuracy with which the sine of the angle of maximum reflection could be resolved, the minimum thickness of solid on which the method could be used, and the effect of using a rubber “boot” to couple the beam from the liquid to the solid. Using a specially constructed transducer positioning device, the sine of the incident angle for peak reflection could be determined within a maximum error of less than ±0.04% at an angle of 13.8°. Unique maximum reflection peaks were obtained on samples having thicknesses greater than 13.5 wave-lengths of the incident wave. No measureable error was introduced by using a boot coupling technique.
Measurement of Dynamic Shear Impedance of Low Viscosity Liquids at Ultrasonic Frequencies
Authors: McSkimin H. J. , Andreatch P.
Published: September 2005

An instrument is described for measuring shear mechanical properties of liquids with viscosities as low as 0.5 cP. Operation is based on an ultrasonic-shear-reflectance method previously used only for more viscous materials [W. P. Mason et al., Phys. Rev. 75, 936–946 (1949)]. In the present apparatus, the considerable increase in sensitivity has resulted primarily from use of an improved method of determining small changes in phase shift for ultrasonic waves reflecting from the solid liquid interface of the instrument. Results at 40 Mc/sec for complex shear impedance and dynamic viscosity are presented for a number of pure liquids. Application to studies of polymer solutions is illustrated by data for a series of polystyrene di-n-butyl phthalate solutions. An ultrasonic method for crosschecking results is described in Appendix A.
Relation between Thermal Ultrasonic Attenuation and Third-Order Elastic Moduli for Waves along the 〈110〉 Axis of a Crystal
Authors: Mason Warren P.
Published: September 2005

When sound waves are transmitted along the 〈110〉 direction in a cubic crystal, the waves consist of combinations of longitudinal and shear waves when referred to the crystalographic axes. In previous publications, it has been shown that shear waves have a relaxation time equal to the thermal relaxation time, while longitudinal waves have a relaxation time about twice as large. Hence, in determining the ultrasonic attenuation due to conversion to thermal phonons, it is necessary to weight the conversion coefficients by this difference in the relaxation time. Tables for the Gruneisen numbers for the 39 pure modes are calculated for the longitudinal and shear waves along the 〈110〉 direction. These tables are applied to the recent measurements of the attenuation of sound waves for lithium fluoride, for which the third-order moduli have also been measured. The large anisotropy of the ultrasonic attenuation for shear waves is accounted for by the third-order moduli used in conjunction with these Tables.
Estimation of an Observed Criterion or Beta0
Authors: Campbell Richard A.
Published: September 2005

The specific steps are provided for estimating an observed-likelihood ratio criterion, beta, given the proportions of hits and false alarms obtained from an observer in the YES NO procedure.
Effect of the Propagation of Internal Water Waves on Underwater Sound Transmission
Authors: Katz Eli Joel
Published: September 2005

A numerical method of computing ray paths by geometric optics in a cylindrically homogeneous medium is outlined, and then applied in extending Lee's investigation of the disturbance to a high frequency sound field by an internal wave field [J. Acoust. Soc. Am. 33, 677–681 (1961)]. In particular, the changes in the ray paths as the wave field propagates between the source and the receiver are displayed on a cathode-ray tube. The resulting fluctuation in the sound intensity field due to the translation of the medium is computed in order to illustrate the signal variance caused by the phenomenon.
Nonlinear Losses Induced in Spherical Waves
Authors: Cary Boyd B.
Published: September 2005

From Naugol'nykh's spherical sawtooth-wave solution, curves are constructed which predict the nonlinear induced extra loss in fundamental amplitude. As in the plane wave case, the propagation path can be split into three zones. In the first zone, nonlinear effects dominate over attenuation. In the second zone, a stable distorted waveform is propagated. In the third zone, attenuation reduces the amplitude so that nonlinear effects are no longer important. Although the predicted losses are smaller than in the plane wave case, they are not negligible. A criterion for cavitation is used in order to define depths in the ocean where cavitation will be the limiting factor on sound power level and not extra losses. By considering a specific example, it is concluded that cavitation will indeed be the limiting factor down to a depth of about 2000 ft. At depths below 2000 ft, extra losses can become significant for propagation from steady-state spherical sources operating below the cavitation threshold.
Axisymmetric Torsional Wave Propagation in Circular Viscoelastic Rods
Authors: Wolosewick R. M. , Raynor S.
Published: September 2005

A semi-infinite viscoelastic circular cylindrical rod is subjected at its end surface to an arbitrary radial, axially symmetric tangential shear stress distribution, harmonic in time. Expressions are derived for the tangential and radial shear stress distributions, as well as for the tangential displacement. Near the forced end of the rod, the tangential displacement takes on a complicated form which consists of the superposition of a simple rotational oscillation of the undeformed cross section and motions deforming the cross section in its plane. The last type of motion permits infinitely many nodal circles. Owing to the large magnitude of the space attenuation coefficients, this second type of motion dies out rapidly and only the simple rotation, which is less attenuated, remains. Numerical computations were performed for two polymethyl methacrylate rods of 1 and 10 cm diam, subjected to a shear stress distribution varying periodically with time and cubic in the radial distance from the center. The results are presented in graphical form.
Lateralization and Intensity Discrimination
Authors: Elfner Lloyd F. , Perrott David R.
Published: September 2005

This study reports the effects of various binaural intensity patterns on the discrimination of changes in the position and intensity of binaurally induced auditory images. The difference limen obtained for just-noticeable shift of an auditory image is in most cases not significantly different from the difference limen observed in discrimination of a just-noticeable change in the intensity of the signal. Only under low intensity levels is such a difference noted. Significant effects are observed as a function of the binaural intensity pattern employed. Also an increase intensity of the signal invariably produced a smaller just-noticeable difference than a decrease in the intensity of the signal. A functional relationship is indicated between image movement and sensitivity to intensity change.
Central Factor in Auditory Fatigue—An Artifact?
Authors: Price G. Richard , Oatman Lynn C.
Published: September 2005

Three experiments were conducted to study further the influence of central factors on pure tone auditory fatigue noted by Wernick and Tobias [J. Acoust. Soc. Am. 35, 1967–1971 (1963)]. Experiment 1 replicated the Wernick and Tobias study and produced similar data. Observations made during Experiment 1 led to several changes in procedure. Experiments 2 and 3 were concerned with the effects of the changes. The results indicated that if S's could resume postexposure threshold tracking without being required to do something else simultaneously (such as write an answer to a problem), the differences between the experimental groups disappeared. Thus, the effect interpreted earlier as being the influence of a central factor seems to be procedural artifact. This interpretation—with one exception, which is discussed—is consistent with the procedure and data of previous experiments.
Effect of Induced Head Movements on Localization of Direction of Sounds
Authors: Thurlow Willard R. , Runge Philip S.
Published: September 2005

Localization of direction of sound sources was studied as a function of induced head movements. High- and low-frequency noise and pulse stimuli were used. Subjects had had no special training and were blindfolded to remove visual cues. Sources were located to the right and left of the subject, in front and behind, and above and below the horizontal plane through the ears of the subject. Induced head rotation was found to be especially effective in reducing horizontal localization error. Rotation, pivot, and rotate-pivot movements caused a small but significant reduction in vertical localization error for low-frequency noise stimuli.
Observation of Circumferential Waves on Solid Aluminum Cylinders
Authors: Goodman R. R. , Bunney R. E. , Marshall S. W.
Published: September 2005

We report on an experiment demonstrating the existence of Rayleigh circumferential waves on solid elastic cylinders. Underwater sound pulses are shown to propagate around a solid aluminum cylinder in an experiment that utilizes transmitters and receivers with narrow beams directed at the cylinder at the critical angles. The theoretical prediction of the accompanying letter by Doolittle et al. is verified.
Contralateral Masking: An Attempt to Determine the Rôle of the Aural Reflex
Authors: Gjaevenes Kjell , Vigran Erik
Published: September 2005

Poststimulatory contralateral masking of pure tones at frequencies 200-1000 cps are determined on normal-hearing subjects. The masker was a high-frequency band noise. Delay interval and noise level have been varied. The masking effect is most probably caused by the middle-ear muscle reflex, but it seems not possible, on basis of the experiments, to decide whether other mechanisms also are involved.
Further Observations on Contralateral Remote Masking and Related Phenomena
Authors: Ward W. Dixon
Published: September 2005

Previous knowledge is reviewed relevant to contralateral remote masking (CRM)—the elevation in threshold of a low-frequency sinusoid the presence of a high-frequency band of noise in the opposite ear—and series of additional observations is presented. CRM is nearly as great (1) in ears with paralyzed middle-ear muscles as in normal ears, (2) for bone-conducted as for air-conducted test tones, or (3) when a 50-msec tone pulse occurs simultaneously with the onset of the masking pulse as when it is presented half a second later. Furthermore, (4) the gradual decrease of CRM with time, in the presence of a sustained masker, is not affected by abrupt changes in frequency or level of the masker, and (5) only a low negative correlation between CRM and auditory fatigue exists. These facts all indicate that the middle-ear muscles play only a minor role in CRM. The course of adaptation of CRM is shown to parallel the course of development of perstimulatory fatigue. It appears, therefore, that CRM represents primarily central masking arising at one or more centers receiving afferent innervation from both right and left ears, and that the change in time of CRM can be ascribed to adaptation processes either in the noise channel or, via the efferent system, in the contralateral channel. Implications of this formulation in regard to auditory fatigue from diotic and dichotic exposure to noise is discussed.
Stress Sensitivity of Piezoelectric Ceramics: Part 1. Sensitivity to Compressive Stress Parallel to the Polar Axis
Authors: Krueger Helmut H. A.
Published: September 2005

Measurements of changes in permittivity, tanδ, and d∂∂ as function of compressive stress parallel to the polar axis are presented for lead zirconate—lead titanate transducer ceramics. The “hard” ceramics (PZT-4 and PZT-8) suitable for high-power application show large changes of properties for stresses to 20 kpsi, but have good recovery on release of stress. The “soft” donor-doped ceramics (PZT-5A and PZT-5H) suitable for detector applications show serious degradation with successive stress cycles. However, for peak stress below about 10 kpsi, their variation of properties and hysteresis within any cycle are less than those of the hard ceramics. Permittivity and tanδ of all these ceramics increase with increase of ac electric field. For the soft ceramics, the tanδ increase is great enough to eliminate their consideration for uses where efficiency or cool operation are necessary. High ac electric field combined with compressive stress reduces these detrimental increases for the soft ceramics and increases them for the hard ceramics. Nevertheless, the hard ceramics remain far superior for high-power high stress uses, with PZT-8 being superior to PZT-4.
Correlation-Detection Arrays Designed for Directional Noise Fields
Authors: Tack Duane H.
Published: September 2005

Coherent likelihood-ratio detectors (having the structure of cross-correlation receivers) designed for binary detection of directional signals in directional noise fields with transducer arrays are investigated. Optimum array geometries for these detectors (ignoring beam-forming requirements) are linear in directional noise fields. Examples of N-element coherent detector performance in propagating and turbulent boundary-layer noise fields are given. They indicate that signal-to-noise ratio (S/N) gains of 10 log10N plus 10 dB per decade decrease in the coherence loss by the noise in traveling between adjacent elements can be obtained if XN1≃1, where XN1 is the product of the data bandwidth times the magnitude of the difference between the noise and signal travel times across the entire linear array.
Capacitance Microphone for Measurement of Small Attenuation Coefficients
Authors: Arnold R. T. , Mackey J. E. , Meeks E. L.
Published: September 2005

An improved capacitive transducer has been designed for use in attenuation and second-harmonic generation experiments in solids. The transducer can be used as both a driver and receiver, and completely eliminates bond corrections in attenuation measurements. Further, it is a broad-band transducer and should prove to be very useful in measurement of attenuation as a function of frequency.
Some Thoughts on Fitzgerald's Particle Waves
Authors: Wilcox R. M.
Published: September 2005

It is pointed out that Fitzgerald's particle-wave theory of deformation in solids is based upon a misconception regarding the nature of phonons. Some experimental objections to the theory are reviewed, and an “Einstein” mass—energy equation is derived from more plausible assumptions than were used by Fitzgerald.
Acoustics Teaching in Secondary Schools
Authors: Underfer Jerry L.
Published: September 2005

The inadequacy of the teaching of sound in secondary schools is emphasized, particularly the laboratory aspect. Mention is made of a project for improvement.
Aural Harmonics: The Masking of a 2000-Hz Tone by a Sufficient 1000-Hz Fundamental
Authors: Clack T. Dean
Published: September 2005

Aural harmonic distortion is generated in normal ears with a constant 1000-Hz fundamental (f1) while the listener traces his threshold for an interrupted 2000-Hz (f2) objective tone. Both tones are presented simultaneously to the same ear with the consequent variations in the masked thresholds recorded during manipulations of the time relation between f1 and f2. The technique and preliminary results are described in the first part of this report. These data show that the threshold shift (TS), produced with an f1 of 60 or 65 dB sensation level (SL), depends critically upon the phase relation of f2 to f1: The TS varies sinusoidally as f2 is phase shifted through one or two complete cycles. Section II presents a discussion of the assumptions used to explain these results. Accordingly, a harmonic series is generated within the ear, vectorial summation occurs between the aural harmonic (AH) and the objective tone, and the task of the listener is to maintain this resultant at some level. An electronic analog model shows that, under these assumptions, the objective f2 would undergo variations approximating sine waves if the AH is at a low effective level compared to that needed to attain audibility. The experiment of Section III confirmed that the general equation, Y = A1 + A2 sin (x+φ), provides a satisfactory description of the variations in TS. In addition, a prediction was derived concerning the phase conditions causing maximum interference, both constructive and destructive. The changes in TS associated with these two phase conditions are approximately equal and opposite as predicted. In fact, the objective f2 is heard at lower intensities than under quiet listening conditions when the f1 intensity was increased up to 60 dB (SPL). This rather bizarre reversal of the usual masking phenomenon, owing to augmentation between the AH and objective f2, was anticipated from the model.
Theory of Signal Detectability: Adaptive Optimum Receiver Design
Authors: Nolte L. W.
Published: September 2005

The theory of adaptive optimum receiver design is presented and its relationship to the classical theory of signal detectability of Peterson, Birdsall, and Fox is presented. The classical theory concentrated on the function description; i.e., the optimum detector for a fixed observation procedure is one that forms the likelihood ratio. Optimum detection performance depends on this input-output relationship. This paper concentrates a more detailed description of the optimum detector; i.e., its realization or implementation. It is shown how optimum detectors can be implemented in a sequential manner, resulting in a receiver configuration that is adaptive. The sequential nature of the adaptive implementation is one in which both a classification and detection output is readily available and, in addition, the design is such that the terminal time of the observation need not be known a priori. The adaptive optimum receiver design theory stresses the use of the receiver memory.
Sound Absorption in Mixtures of Oxygen and Water Vapor
Authors: Harlow R. George , Nolan M. E.
Published: September 2005

Measurements of the absorption of sound in mixtures of oxygen and water vapor are given. The results agree closely with those of H. and L. Knotzel; Harris and Tempest; and Henderson, Clark, and Lintz. They can be described by the equation: f0=9 + 162h + 114h2, where f0 is the frequency of maximum absorption in hertz at a pressure of 1 atm and h is the molar fraction of water vapor × 103. The measurements suggest that the results of Harlow and Kitching were subject to error due to surface adsorption.
Source Levels for Deep Underwater Explosions
Authors: Christian Ermine A.
Published: September 2005

Recent near-surface measurements are combined with previous data to provide spectral energy curves for underwater explosions at depths between 120 and 22 000 ft. Reduced spectra extrapolated back from the surface to 1O0 yd range from the burst (R−2 spreading assumed) can serve as “effective source levels,” for deep explosions. The variation of spectral gradient with burst depth is discussed briefly.
ACOUSTIC TRANSMISSION AUGMENTATION ACROSS AN AIR/WATER INTERFACE
Authors: Thorpe Howard A.
Published: September 2005

Experiments and results are briefly described concerning augmented acoustical coupling across air/water interfaces as predicted by elementary quarter-wave plate coupling theory. Greatest augmentation observed so far has been 15 dB at about 500 Hz with soft rubber as the coupling material.
SEQUENTIAL PROGRAMMER FOR PSYCHOPHYSICAL TESTING
Authors: Levitt H. , Bock D. E.
Published: September 2005

A device for sequentially programming stimulus sequences in psychophysical experiments is described. The apparatus is designed specifically for tests involving a quantal response. A variety of sequential strategies can be programmed, including the Up-Down-Transformed-Response (UDTR) procedure. Several strategies can be run either in sequence or concurrently, or both. Connecting strategies in sequence allows for the most appropriate strategy to be used at each stage of an experiment. Running several strategies concurrently enables two or more points on the psychometric function to be estimated simultaneously. Thresholds and difference thresholds may be measured simultaneously and with relative precision using this technique.
Formant Frequency Regions of Polish Vowels
Authors: Majewski Wojciech , Hollien Harry
Published: September 2005

Frequency regions of the first two formants of Polish vowels are given. The method included specification of these formants by spectral analysis of spoken vowels and by perceptual evaluation of synthetic vocalic stimuli.
Mutual Acoustic Impedance between Flexible Disks of Different Sizes in an Infinite Rigid Plane
Authors: Chan Kwai-Cheung
Published: September 2005

A direct method of analysis based on the “classical” Rayleigh formula is presented for calculating the mutual acoustic impedance between circular radiators of different sizes in an infinite rigid plane. The effects of the interactions between two radiators are considered in detail. The acoustic pressure on the plane baffle is described by a distribution of surface “sources” of known strength at the plane-fluid boundary. As the sound-pressure field produced by one radiator exerts a force on another radiator on the plane, the mutual radiation impedance can be defined by the force exerted by one radiator integrated over the surface of the other. This impedance is expressed by a series solution of products of Bessel functions. The results can be reduced to those found by Pritchard and Porter, who based their solutions of the problem as formulated by Bouwkamp. Numerical calculations for the series solutions of the pressure field and of the mutual impedance terms are not given. Attention is paid only to mathematical formulisms.
Masker Level and Sinusoidal-Signal Detection
Authors: Campbell Richard A. , Lasky Elaine Z.
Published: September 2005

Threshold signal-to-masker ratios were obtained or a 1000-Hz signal presented with either an identical frequency sinusoidal masker or a complex masker consisting of the same frequency as the signal plus two sidetones 300 Hz on either side of the central component. Data considered include signal durations of 20, 400, and 1000 msec with masker durations either equal to that of the signal or continuous for the block up-and-down, two-interval, forced-choice threshold run. The parameters of primary interest were the level of the masker and whether the masker was gated or continuous. The thresholds appear to indicate that when the excitation pattern of the masker is increased (by shortening its duration or adding sidetones) so as to equal or surpass that of the signal, masked thresholds tend toward an inverted-N function, as related to masker level, rather than being independent of masker level. Also, differences between the gated and continuous masker thresholds do not appear to be related to changes in signal uncertainty as reflected in the slopes of psychometric functions.
Explanation of Masking-Level Differences That Result from Interaural Intensive Disparities of Noise
Authors: Dolan Terrence R. , Robinson Donald E.
Published: September 2005

The detectability of a monaurally presented 500-cps signal was measured at each of several values of interaural correlation for a wide-band noise masker. The results, when expressed in terms of masking-level differences (MLD's), are in agreement with data reported by Whitmore and Wilbanks and show a function of similar form to that described by Robinson and Jeffress. Additionally, the detectability of a monaural signal was investigated as a function of the interaural intensive relations of a wide-band noise masker. The data are in agreement with results originally shown by Hirsh, and since, replicated several times. That is, detectability is greatest when the level of the noise masker at the two ears is equal, and decreases as the level of the masker at the nonsignal ear is attenuated. The data are used to estimate parameters for a simple model that attempts to account for changes in detectability that occur when a monaural signal is presented with binaural, correlated noise having an interaural level difference. The model proposes that at low external noise levels, internal noise leads to a decrease in interaural-noise correlation. Predictions from the model are in reasonable agreement with data reported previously.
Effects of Context on Talker Identification
Authors: Young Martin A. , Campbell Richard A.
Published: September 2005

The ability to identify talkers from monosyllables spoken in context was examined: Kersta's method of visually comparing spectrograms was employed. Ten observers were trained to identify five talkers from spectrograms of two words spoken in isolation. The experimental task then required the observers to identify the same talkers from the same words spoken in different contexts. The correct rates for the training task (78.4%) could not be reproduced in the experimental task (37.3%). The results were interpreted to indicate that different contexts decrease the identification ability of observers because: (a) the shorter stimulus durations of words in context decreases the amount of acoustic information available for matching, and (b) the different spectrographic portrayals introduced by different phonetic contexts outweighs any intratalker consistency.
Piezo-Optic Coefficients of Liquids
Authors: Riley W. A. , Klein W. R.
Published: September 2005

A pulsed ultrasonic light diffraction technique was used to obtain values of the piezo-optic coefficient for 24 liquids. From these results, several empirical expressions were obtained that facilitate calculation of this parameter.
Vibrations of Fluid-Filled Spherical and Spheroidal Shells
Authors: Rand R. , DiMaggio F.
Published: September 2005

Frequency equations and mode shapes are obtained in analytic form for the axisymmetric, extensional, nontorsional vibrations of fluid-filled elastic spherical shells and rigid prolate spheroidal shells, while a numerical scheme is developed for the fluid-filled elastic prolate spheroidal shell. Extensive numerical results in the form of frequency spectra and mode shapes for these problems are displayed.
Frenet Formulation of Three-Dimensional Ray Tracing
Authors: Eby Edward S.
Published: September 2005

An approach to three-dimensional ray tracing, based on the ray equations and Frenet formulas, is developed. It is applied to two families of constant sound-speed surfaces for which Snell's laws are not known: coaxial circular cylinders and concentric ellipsoids. The classically known results for the cases of parallel planes and concentric spheres are rederived in terms of the present formulation. It is shown that the ray-tracing equations for concentric spheres can be transformed exactly into those for parallel planes. For the coaxial cylinder case, pseudo-Snell's laws can be derived even though the ray paths are not plane curves. For the family of ellipsoids, no Snell's law was found, but ray paths are plane curves. The examples considered do not exhaust the applicability of this ray-tracing approach, but are meant only to illustrate the technique.
Specific Volumes of Water at High Pressures, Obtained from Ultrasonic-Propagation Measurements
Authors: Vedam Rajagopalan , Holton Gerald
Published: September 2005

A computer-aided procedure has been developed for obtaining specific volumes from measured ultrasonic velocities in any nondispersive medium. Newly measured velocities up to 80°C and 10 000 kg/cm2 have yielded values of specific volumes and a number of thermodynamic coefficients for water over this same range. P. W. Bridgman's measurements of specific volumes in the high-pressure range showed systematic differences of a few tenths of a percent; the present calculations yield values believed to be good to 0.05% or better for most of the range.
Brillouin Scattering and Relaxation in Liquids
Authors: Montrose C. J. , Solovyev V. A. , Litovitz T. A.
Published: September 2005

The spectrum of light inelastically scattered from density fluctuations is considered both for nonrelaxing and relaxing fluids. When the thermal conductivity of the liquid is small, the functions describing these spectra take on particularly simple forms. In addition to the unshifted Rayleigh line, caused by scattering from isobaric density fluctuations, the spectrum for a nonrelaxing liquid is just the response of a resonant system driven by thermal energy. For a relaxing liquid, the spectral distribution function has a somewhat more complicated form, but its interpretation is still quite straightforward. The use of electric circuit equivalents illustrates the principal features of the response spectrum. These results are formal ones, but while they are useful in understanding the scattering process, they are not particularly suited for the analysis of experimental results. For this purpose, approximations are developed that enable one to relate the out-standing characteristics of the spectrum (for example, the positions and half-widths of shifted lines) to fundamental relaxation parameters, such as the longitudinal storage and loss moduli.
Surface-Reflected/Bottom-Reflected Ray Transmissions in a Divergent Channel
Authors: Jacobson Melvin J. , Warfield J. Thomas
Published: September 2005

Surface-reflected/bottom-reflected ray transmissions in a divergent channel are studied when the sound velocity decreases linearly with depth. The sound source and receiving point are located on the bottom. Under certain simplifying assumptions, ray geometry is examined, and conditions are given under which a ray is surface reflected, refracted, or a combination of these. Expressions are developed for travel time and geometrical spreading loss. For an isovelocity medium, initial ray angle, travel time, and spreading loss of individual arrivals are examined as functions of bottom angle. These quantities are shown to be greater for a divergent channel than for a horizontal channel. Assuming a CW source and Rayleigh reflection theory, the total field at a receiving point is determined. It is found that the variation in intensity values decreases with increasing bottom divergence.
MLD's and the Phase Angle, Alpha
Authors: Jeffress Lloyd A. , McFadden Dennis
Published: September 2005

This Letter describes two experiments designed to discover the effect of the phase angle, α (the angle between a narrow-band masker and a tonal signal), on binaural detection, and offers an explanation of why they failed to reveal any effect.
Nonlinear Attenuation of Sound in a Duct
Authors: Ingard Uno
Published: September 2005

Transmission of sound in a duct with a nonlinear acoustic wall impedance is discussed. As a quantitative example, the pressure distribution along a duct in the low frequency approximation is calculated for a particular type of duct lining with known nonlinear characteristics.
Force on a Bubble in a Standing Acoustic Wave
Authors: Eller Anthony
Published: September 2005

Bubbles can be trapped by a standing sound wave in a liquid. An expression is derived for the force exerted on a spherical bubble by the sound field, and experimental results are presented in support of the theory.
Ultrasonic Doppler Shift as an Aid to Diagnostic Ultrasonic Scanning
Authors: Kelsey Charles A.
Published: September 2005

The location of a pulsed ultrasonic scan within the body can be determined using an ultrasonic Doppler shift detector. The technique is also valuable for avoiding gas bubbles in the stomach or intestine, The scattered or reflected beam is detected by the receiving crystal of the Doppler unit. Localization of the pulsed beam is accomplished by searching for a maximum output signal from the Doppler unit.
Quick Characterization of the Directional Response of Point Array
Authors: Lowenstein Carl D. , Anderson Victor C.
Published: September 2005

The directional response of a two- or three-dimensional point array is a function of two independent directions and also a function of frequency. A suitable mapping of these three parameters into a pseudodirection and a pseudofrequency allows the examination of the major and minor lobe structure of the array response with only a two-parameter computation. This method has been applied during the design of a 32-element planar array, to permit adjustment of the element positions for a minimum and uniform minor-lobe structure.
Effects of Intensity on “Critical Bands” for Tonal Stimuli as Determined by Band Limiting
Authors: Bourbon Walter T. , Evans Thomas R. , Deatherage Bruce H.
Published: September 2005

Four subjects were run in a 2IFC psychophysical study in auditory masking. The signal consisted of a 100-msec tone burst delivered in phase to the two ears. Signal frequencies between 250 and 4000 Hz were used. The masking noise had spectrum levels of 45, 25, and 15 dB SPL. For each signal frequency, the signal level was found that produced P(c) of 0.54 in wide-band noise at each spectrum level. The high- and low-frequency cutoffs of the noise were then varied independently (band limited), and changes in detectability were observed. Detectability remained constant until the cutoff of the noise was raised or lowered to a critical value; from that point on, detectability improved. The function traced by improvement in detectability represents the “critical band” for the stimulus conditions used. The width of the critical band was directly related to stimulus intensity for all signal frequencies.
Loudness Determination at Low Sound Frequencies
Authors: Hellman R. P. , Zwislocki J. J.
Published: September 2005

The validity of a previously introduced psychophysical method of numerical magnitude balance is discussed. The method is applied to loudness scaling at low sound frequencies. The results are shown to agree with loudness-matching data obtained in several investigations.
Testing for Sequential Dependencies
Authors: Levitt H.
Published: September 2005

Certain psychophysical procedures assume that successive responses are statistically independent. A method for testing the validity of this assumption using the up-down procedure is described. Two identical up-down strategies are run concurrently. Observations for each strategy are interleaved according to a rule designed to produce a large difference between the resulting estimates should a sequential dependency exist. The null hypothesis that no dependency exists is postulated, and the two estimates are compared for differences significantly larger than could have occurred by chance. The experiment reported here was designed to test the possibility that responses of the same type are more likely to follow in sequence than would occur with statistically independent judgments. The masked threshold for a 250-Hz tone in wide-band noise was measured for five subjects on three separate occasions. Two of the five subjects showed a small but consistent difference between the two concurrent estimates, indicating a slight tendency for like responses to follow in sequence. The technique of interleaving by rule may also be of value in measuring hysteresis effects and in detection-theory experiments, where it may be possible to discriminate between sequential effects influencing the subject's sensitivity and those affecting the subject's choice of criterion.
Vowel Quality and Musical Timbre as Functions of Spectrum Envelope and Fundamental Frequency
Authors: Slawson A. W.
Published: September 2005

Observers gave magnitude estimations of the difference in sound quality between the members of pairs of vowellike synthesized sounds. The observers in one set of experiments were asked to judge differences in vowel quality; those in an analogous set of experiments, differences in musical timbre. The first sound in each pair—the standard—was an imitation of one of six English vowels. The second sound in each pair—the test sound—was derived from the first by modifications of the fundamental frequency, the formant frequencies, or certain combinations of both. When the fundamental of the second sound was raised an octave above the frequency of the first, the estimates of difference—both in vowel quality and in musical timbre—could be reduced to a minimum, if the frequencies of the two lower formants of the sound with the higher fundamental were multiplied by a factor of 1.10. The judgments both of vowel quality and of musical timbre indicated that small changes in the frequencies of the two lower formants made large differences in quality, that small differences in quality could be attributed simply to changes in the fundamental frequency, and that still smaller quality differences could be attributed to changes in the frequencies of the higher formants alone. Shifts in the spectrum envelopes of sounds corresponding to the compact vowels resulted in greater apparent differences in both vowel quality and musical timbre than comparable shifts in the spectrum envelopes of the noncompact sounds. The results suggest that vowel quality and musical timbre are similar functions of their common acoustic correlates, that perceived invariances in the quality of sound cannot be attributed to learning, and they support a modified “fixed pitch” or formant theory of quality.
Structural Interaction Effects on Shock Spectra
Authors: Cunniff P. F. , Collins R. P.
Published: September 2005

A study has been made of the influence on shock spectrum curves of the interaction between a superstructure and its nonrigid foundation. Such interaction causes the spectrum values of interest to lie in the valleys corresponding to the superstructure's fixed base natural frequencies, while the peak spectrum values occur at the combined system natural frequencies. Normal mode theory for lumped mass systems is reviewed briefly and the necessary equations are presented. These equations demonstrate how shock spectrum data are applicable for calculating deflections, stresses, etc., for structures subjected to transient excitations. The concept of design shock spectra is discussed, and an example shows how design spectrum data might be applied to a particular case.
Transient Acoustic Fields Generated by a Body of Arbitrary Shape
Authors: Farn C. L. S. , Huang H.
Published: September 2005

The transient process in acoustic fields generated by the time-dependent motion of an arbitrary body submerged in an infinite, inviscid, and slightly compressible fluid is formulated by the source-density method. The governing equations of the source density are solved exactly for the acoustic field generated by the arbitrarily time-dependent motion of a rigid, circular baffled piston in a rigid infinite plane. In the general case, a numerical method of predicting the transient pressure field is developed according to the source-density formulation. Three numerical examples are presented to demonstrate the versatility of the method. The numerical method proves to be useful for small values of time. However, for large values of time, the error introduced in the numerical solution becomes unacceptably large and the method is no longer valid.
Optimum Waveforms for Correlation Detection in the Sonar Environment: Noise-Limited Conditions
Authors: Kincaid Thomas G.
Published: September 2005

Sonar systems currently in use and under development attempt to discover the presence of an underwater target by transmitting an acoustic pulse and detecting the echo with a correlation receiver. This receiver correlates its input with time and frequency translates of a stored reference waveform, usually the same as the transmitted waveform. Owing to the presence of random multipath, there is usually not a single echo, but a multiplicity of echoes with random attenuations, time delays, and frequency shifts. Under these conditions, the detection capability of the correlation receiver is shown to be dependent upon the transmitted and reference waveforms. Necessary and sufficient conditions for optimum waveforms under a maximum signal-to-noise ratio criterion with an energy constraint are derived. A technique for finding waveforms that satisfy only a necessary condition is demonstrated, but it is conjectured that it produces the optimum waveforms. Conjectured optimum waveforms are derived for selected examples, and their performance compared to that of some conventional waveforms.
Aural Harmonics: Preliminary Time-Intensity Relationships Using the Tone-on-Tone Masking Technique
Authors: Clack T. Dean
Published: September 2005

Variation in sensitivity to an objective 2000-Hz harmonic (f2) is produced at different intensities with a 1000-Hz fundamental (f1) masker. This continuous f1 pure tone is presented monaurally at 57, 61, 65, 67, 69, 71, or 74 dB SPL to each of seven normal ears. Simultaneously, the listeners trace Békésy-type thresholds for the interrupted f2 in the same ear. This objective f2 is then phase shifted, in 60° steps, through 360°. The threshold shift (TS) obtained has been described previously by the general equation, TS = A1+A2×sin (X+Φ). The present purpose is to confirm this observation by examination of a range of f1 intensities and to analyze separately any systematic changes in the three dependent variables; A1, A2, and Φ. Explanations of the effect of f1 intensity upon these parameters are derived from a model that makes three major assumptions: (a) The ear generates an aural harmonic (AH); (b) the AH sums vectorially with the objective f2; and (c) the listener maintains a threshold response. The mean TS results fit the above equation at all f1 intensities sampled here. Detailed analysis of the three dependent parameters reveals: (1) Linear increases in A1 (slope 2.0–2.5 dB) for f1 intensities above 60 dB; (2) complex changes in A2 with relatively large individual differences; and (3) independence of Φ from increases in f1 intensity. The simple model is useful in explaining the mechanisms underlying these parameters in the range of f1 intensities from about 45–50 dB to 74+ dB SPL.
Receiver-Operating Characteristics Determined under Several Interaural Conditions of Listening
Authors: Emmerich David S.
Published: September 2005

The ability of subjects to detect sinusoidal signals in a continuous background of white Gaussian noise was investigated for several different interaural relations of the signal and of the noise stimuli. The functions, referred to as receiver operating characteristics (ROC's), relating the proportion of correct detections of the signal to the proportion of false alarms were determined in each case. A rating procedure was employed to determine the ROC's. The area under the ROC was found to be a good estimate of the percent correct obtained with a two-interval forced-choice (2IFC) technique—a relation to be expected on theoretical grounds. The ROC's were not significantly affected by the presence of trial-by-trial feedback.