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Journal of the Acoustical Society of America

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Dec 1976

Volume 60, Issue 6, pp. 1249-1412


Physical optics farfield inverse scattering in the time domain

Norman Bleistein

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1249-1255 (1976); (7 pages)

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The physical optics farfield inverse scattering (POFFIS) identity relates the phase‐ and range‐normalized farfield backscattering amplitude to the spatial Fourier transform of the characteristic function of the scattering obstacle. The characteristic function is equal to unity in the region occupied by the obstacle and zero elsewhere. The original identity was derived by Bojarski for impulsive point sources. Here we extend the result to sources of arbitrary time dependence. We obtain an alternative form of Bojarski’s POFFIS identity. We also derive a POFFIS identity in the time domain. Numerically synthesized checks on the method are provided.
Subject Classification: [43]20.30.
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43.20.+g General linear acoustics

Fluid‐loading influence coefficients for a finite cylindrical shell

B. E. Sandman

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1256-1264 (1976); (9 pages) | Cited 1 time

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The fluid radiation loading exhibited by a finite cylindrical shell with rigid immovable end plates is investigated by implementing the methods of Fourier integral transforms. The solution is obtained for a generalized velocity distribution on the cylindrical surface. The numerical solution for a radially pulsating surface is utilized as the basis for comparison to previous investigations. In addition, the radiation loading displayed by the low‐order modes of a simply supported shell section is obtained, and the relative effect of the imposed condition of an infinite cylindrical baffle embodying the shell is ascertained. It is shown that the classical solution for a vibrating band on an otherwise rigid surface offers a reasonable approximation in the determination of the fluid radiation loading imparted to a finite cylindrical shell with rigid end closures.
Subject Classification: [43]20.60.
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43.20.+g General linear acoustics

Multiple scattering between a cylinder and a plane

J. C. Bertrand and J. W. Young

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1265-1269 (1976); (5 pages) | Cited 10 times

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Experimental measurements of the backscattering of a plane acoustic wave by a rigid cylinder parallel to an elastic plate are compared with theoretical calculations. Two sets of calculations, one which includes the effects of multiple scattering between the cylinder and the plate abd one which ignores multiple scattering between the cylinder and the plate and one which ignores these effects, were performed. The measurements were done in fresh water these effects, were performed. The measurements were done in fresh water using a 5.08‐cm‐diam solid steel cylinder at various distances from a 0.635 cm‐thick steel plate. The frequency of the incident wave was varied from 50 to 100 kHz. Comparisons between the theories and experiment were made both for the case of the cylinder in front of the plate and for the case of the cylinder behind the plate. The results confirm that multiple scattering effects should be included in these scattering calculations.
Subject Classification: [43]30.40; [43]20.30.
Show PACS
92.10.Vz Underwater sound
43.20.+g General linear acoustics

Reevaluation of Wilson’s sound‐speed measurements for pure water

Chen‐Tung Chen and Frank J. Millero

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1270-1273 (1976); (4 pages) | Cited 4 times

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The pure‐water high‐pressure sound‐speed data of Wilson have been analyzed, and it is concluded that all Wilson’s values should be shifted by the apparent error of his 1‐atm values. A new equation has been determined to represent the shifted pressure data of Wilson, as well as the best 1‐atm data of Del Grosso and Mader.
Subject Classification: [43]30.25.
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92.10.Vz Underwater sound

Multipath acoustic propagation with a moving source in a bounded deep ocean channel

J. G. Clark, R. P. Flanagan, and N. L. Weinberg

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1274-1284 (1976); (11 pages) | Cited 4 times

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An analysis is presented for coherent multipath propagation between a moving source and a fixed receiver. The major mulitpath effects of source motion are frequency spreading range or emission‐coordinate spreading, and travel‐time spreading of the multipath arrival set. These are analytically related to the signal propgation as functions of time and velocity. Computer simulations with a shallow moving source and a fixed receiver below the SOFAR channel are presented which clearly illustrate the contributions of source motion developed in the analysis.
Subject Classification: [43]30.20 [43]20.20..
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92.10.Vz Underwater sound
43.20.+g General linear acoustics

Coupled power equations for cylindrically spreading waves

Suzanne McDaniel

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1285-1289 (1976); (5 pages) | Cited 1 time

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Equations are derived for the power transferred between normal modes due to scattering from weak, random variations in the horizontal strati‐ fication of the ocean. Perturbation theory is used to obtain results for a horizontally isotropic medium. The validity of these results is discussed for the case of dorward scattering. The modal power transfer given by two‐ dimensional model will, in many cases, suffice to estimate modal power transfer.
Subject Classification: [43]30.20; [43]20.15.
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92.10.Vz Underwater sound
43.20.+g General linear acoustics

Infrasonic sea noise at the Mid‐Atlantic Ridge near 37°N

James R. McGrath

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1290-1299 (1976); (10 pages)

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Infrasonic and low‐frequency sonic sea noise was recorded for seven days in the 5‐ to 32‐Hz band in the seismically active rift valley of the Mid‐Atlantic Ridge near the Azores. Two ocean bottom seismographs (OBS) in water depths of about 2400 m made continuous, simultaneous recordings of acoustic and seismic signals generated by seaquakes. The dominant source of deep sea noise averaged over the recording interval was distant shipping traffic, deduced by comparing mean OBS levels to Wenz’s shipping noise estimates. Mean spectrum levels between 5 and 10 Hz did not exceed 80 dB//μPa, while mean levels at frequencies above 10 Hz were higher. The mean spectrum level at 5 Hz was about 9 dB lower than at 30 Hz, indicating that distant shipping traffic noise does not contribute to the noise field below 5 Hz. Radiated noise due to nearby ship passages comprised about 13% of the recording time and produced spectral lines at frequencies as low as 6.5 Hz. Over 515 seismic events were detected by one OBS unit; epicenters were estimated to be from 3 to 10 NM from the instrument. Seaquakes took place at a mean rate of 2.9 events/h, persisted from 12 sec to about 2 min, varied in Richter magnitude from 0 to 2.5, occurred as a swarn on at least one occasion and often raised broadband acoustic levels in excess of 20 dB.
Subject Classification: [43]30.70; [43]28.30.
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92.10.Vz Underwater sound
43.28.+h Aeroacoustics and atmospheric sound

Abnormal attenuation in Chesapeake Bay waters

William R. Turner

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1300-1308 (1976); (9 pages)

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During a 1957 field study at the Chesapeake Bay, abnormal attenuation was detected in 18% of the 1.0‐MHz data, 22% of the 2.0‐MHz data, and 45% of the 3.0‐ and 5.0‐MHz data. This ranged from 0.4 to 7.4 dB/m above the attenuation of fresh water. The interpretation of the data was facilitated by stable water conditions and the strong location orientation of results which permitted a separation of variables. The added attenuation appears to arise wholly from the presence of microbubbles which enter principally from atmospheric aerosols. The absence of abnormal attenuation in regions that receive significant drainage from residential and industrial areas is attributed to trace chemicals that modify of manner the microbubble stabilization. In regions of heavy ship traffic, on the other hand, wake bubbles may transport these trace chemicals to the surface, leaving a residue of smaller microbubbles that produce a high level of excess attenuation.
Subject Classification: [43]30.20.
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92.10.Vz Underwater sound

Absorption of ultrasound in Freon‐12

H. W. Jones, D. Stredulinsky, and P. J. Vermeulen

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1309-1310 (1976); (2 pages)

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Measurements of the absorption of sound in Freon‐12 are reported for a range of f/p of 104–105 (Hz/atm). The data are shown in relation to similar data obtained at higher frequencies.
Subject Classification: [43]35.20.
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43.35.-c Ultrasonics, quantum acoustics, and physical effects of sound

Interferometer method for the measurement of the ultrasonic properties of solids

J. Kritz

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1311-1313 (1976); (3 pages)

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An interferometer method for the measurement of the ultrasonic propagation velocity and absorption coefficient in solids is described. The method provides a simple procedure to permit accurate evaluation using standard laboratory test instruments. Impedance and frequency measurements at successive maxima and minima are made using a half‐wave transducer coupled to a short sample. Experimental results of velocity versus temperature and absorption coefficient for polystyrene at 2 MHz are given and the results compared with other published values.
Subject Classification: [43]35.80, [43]35.26.
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43.35.-c Ultrasonics, quantum acoustics, and physical effects of sound

Shock spectrum of a two‐degree‐of‐freedom nonlinear vibratory system

R. M. Root and P. F. Cunniff

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1314-1318 (1976); (5 pages) | Cited 1 time

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The shock spectrum of the foundation or isolator mass of a two‐degree‐of‐freedom vibratory system was studied. The system had a cubic hardening elastic nonlinearity in the foundation or isolator restoring force. The system was impulsively shocked, and analytical, experimental, and numerical methods used to determine the resulting shock spectrum. The system was studied theoretically in two ways. An analytic solution was developed using a perturbation expansion of the nonlinear equations of motion, combined with an analytic solution for the shock spectrum due to the motion. A numerical solution to the nonlinear equations of motion was developed and used to verify the range of validity of the solution developed from the perturbation expansion. The nondimensional parameter of the perturbation expansion was found to be directly dependent on the coefficient of the cubic hardening spring and the square of the initial velocity of the foundation or isolator mass, and inversely dependent on the generalized mass and the fourth power of the natural frequency of each linear mode. The numerical solutions of the equations of motion verified that variations in this parameter defined the degree to which the behavior of the nonlinear system departed from the behavior of the linear system. The theoretical studies predicted that the cubic hardening spring would cause the peaks in the shock spectrum corresponding to the linear natural frequencies to be shifted to higher frequencies, and that significant additional peaks would be introduced at combinations of the shifted frequencies. An experimental study of a two‐degree‐of‐freedom system with a cubic hardening spring was undertaken. The experimental results verified shifting of the frequencies of the peaks and introduction of additional peaks in the shock spectrum.
Subject Classification: [43]40.40, [43]40.30, [43]40.60.
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43.40.+s Structural acoustics and vibration

Array processors for simultaneous noise and interference suppression or simultaneous signal‐to‐noise and resolution enhancement

Gerald C. Glaser and Ross E. Williams

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1319-1330 (1976); (12 pages)

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See Also: Erratum

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A symmetrical treatment is described of signal and interference arrivals, both spatially coherent across the aperture of a receiving array and appearing in a generalized ambient‐noise background. By separating the coherent interference from the rest of the noise background, it is possible to implement a simple form of adaptive suppression of the interference, particularly when the latter is time varying and the remainder of the noise is stationary. Optimal processors are derived for simultaneous suppression of noise and interference, and for enhancement of the signal‐to‐noise ratio after elimination of interference. The processor for the latter case is shown to be a suboptimum version of the former. Both deterministic and stochastic interference are considered, as well as interference whose arrival time is synchronized with that of the desired signal (e.g., unwanted signal multipath arrivals, reverberation, etc.). Processors for two or more simultaneous and independent interference sources are described. Finally, the interference descriptor can be reinterpreted as a generalized resolution measure, so as to describe processors that simultaneously maximize the signal‐to‐noise ratio and the signal time resolution, or the signal‐to‐noise ratio and a combination of arrival angle and time resolution.
Subject Classification: [43]60.30.
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43.60.+d Acoustic signal processing

Design approach for quadrature sampled digital bandpass filters

D. E. Kerr and M. W. Lengyel

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1331-1334 (1976); (4 pages)

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A design procedure is developed for digital bandpass filters having quadrature sampling. The design process is developed from Nth‐order bandpass sampling reconstruction theory. These filters possess properties that satisfy the requirements of a class of digital filter problems.
Subject Classification: [43]60.20; [43]85.32.
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43.60.+d Acoustic signal processing
43.58.+z Acoustical measurements and instrumentation

Perceived roughness of amplitude‐modulated tones and noise

Miguelina Guirao and J. M. Garavilla

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1335-1338 (1976); (4 pages)

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Two sets of studies were conducted to determine the perceived auditory roughness of pure tones and narrow bands of noise modulated in amplitude. The signals used as carrier frequencies were 500‐ and 2000‐Hz tones and two narrow bands of noise centered at the same two frequencies. Auditory roughness was measured by the psychophysical methods of magnitude estimation and a combination of magnitude estimation and magnitude production procedures. The average of the numerical estimates given by 10 Ss and the adjustments made by each one of the 40 Ss were plotted versus the degree of modulation m=Δ p/p of the SP. Results indicate that the perceived auditory roughness functions can be described by a power function with an average exponent of about 1.4. The exponent was about the same for the amplitude fluctuations of tones and noises.
Subject Classification: [43]65.75.
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42.66.-p Physiological optics

Lateralization of complex waveforms: Effects of fine structure, amplitude, and duration

John M. Nuetzel and Ervin R. Hafter

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1339-1346 (1976); (8 pages) | Cited 20 times

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In recent years there has been an increased interest in the use of interaural time as a cue for lateralization at high frequencies. Our study examines this question using AM complexes with carriers of 1800, 2400, 3000, 3600, 3900, 4200, and 4500 Hz, modulated at 300 Hz and interaurally delayed. The findings indicate that (a) the ability to lateralize these stimuli does not depend on low‐frequency distortion, since this ability remains despite the presence of intense low‐frequency masking; (b) the task is easier when the entire waveform, rather than just the modulation envelope, is delayed, though this difference seems to decline with practice; (c) the effects of stimulus amplitude and duration on the detection of interaural time differences are reminiscent of those observed with pure tones, although ongoing time differences may be more fully utilized with AM signals; and (d) lateralization declines with interaural carrier frequency discrepancy. We were unable to obtain lateralization of AM complexes at one ear against pure tones (at the modulation frequency) at the other. This strengthens the argument that all stimulus information used is carried in high‐frequency channels.
Subject Classification: [43]65.62.
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42.66.-p Physiological optics

Temporal recognition masking—or interference?

David W. Sparks

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1347-1353 (1976); (7 pages) | Cited 1 time

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Several experiments were performed in which brief tonal target bursts centered around 820 Hz were preceded and followed by interference signals. These interference signals included tones and noise bursts having a variety of durations, intensities, and center frequencies. Interference signals were ipsilateral or contralateral to the ear receiving the tonal targets. Backward recognition interference was observed with tonal maskers when target‐masker frequency separations were within 10 Hz. No interference was observed with noise maskers. Aggregate results from these experiments suggest that disruptions in tonal recognition must occur after a preliminary perceptual analysis.
Subject Classification: [43]65.54, [43]65.75.
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42.66.-p Physiological optics

Temporal factors in vowel perception

Brian L. Scott

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1354-1365 (1976); (12 pages)

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The perceptual role of the temporal fine‐structure of vowel waveforms was investigated in five experiments. The interaction of the fundamental frequency and the first formant (F1) was shown to result in temporal  patterns  consisting of a number of cycles of F1 per fundamental frequency period. Changes in these  patterns  were shown to correlate with shifts in the perceptual boundary between /i/ and/I/. The results indicate that the perceptual system was responding to either a change in number of cycles of F1 per fundamental period or a change in the harmonic structure of the sounds. The hypothesized temporal cue was then used in synthesizing vowel‐ like sounds which, while not differing in formant center‐frequency or harmonic structure, did differ in temporal structure. Subjects were able to match different sequences if the vowel‐like sounds with sequences of natural vowels as predicted by their temporal properties. In a subsequent experi‐ ment, two pure tones were used as  building blocks  for synthesizing the vowels a, e, i, o, and u. With careful temporal modeling, the two tones proved sufficient fpr synthesizing intelligible tokens of the five vowels. Although the possibility exists that all the results may be explained in terms of spectrum, the indications are that temporal properties play a considerable role in vowel perception.
Subject Classification: [43]70.30; [43]65.75.
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43.70.-h Speech production
42.66.-p Physiological optics

On the mechanics of vocal‐fold vibration

Ingo R. Titze

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1366-1380 (1976); (15 pages) | Cited 12 times

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The human vocal fold is treated as a continuous, transversally isotropic, bounded medium. The theory of viscoelasticity is applied to formulate the stresses, strains, glottal tissue impedance, and propagation characteristics for sinusoidal oscillation within the vocal‐fold tissues. Incompressibility of the tissues leads to a biharmonic differential equation, the solution of which represents commonly observed modes of vibration. The energy dissipated in the tissues and the associated damping factors are calculated. Mode impedances of the tissues are calculated and lumped‐model approximations of the system evaluated. The usual mass‐spring models are shown to be inadequate in certain important cases, especially during vocal‐fold closure and for modes in which vertical phase differences occur.
Subject Classification: [43]70.20.
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43.70.-h Speech production
43.20.+g General linear acoustics

Discriminability, response bias, and phoneme categories in discrimination of voice onset time

Charles C. Wood

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1381-1389 (1976); (9 pages) | Cited 3 times

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The ’’phoneme‐boundary effect’’ refers to the observation that discrimination of stop consonants across a boundary between phoneme categories is superior to discrimination of comparable stimulus differences within a phoneme category. The present experiment employed signal detection methodology (a) to distinguish between changes in discriminability and response bias; and (b) to reevaluate the role of phonetic categorization in the phoneme‐boundary effect. A SAME–DIFFERENT discrimination task compared discrimination of 10− and 20−msec differences in voice onset time (VOT) in a synthetic stimulus continuum ranging from [ba] to [pa] (VOT’s from −50 to +70 msec). Both a clear increase in discriminability and a marked shift in response bias from SAME to DIFFERENT occurred near the voiced–voiceless boundary. When variations in VOT were isolated from syllable context so that they were not categorized as phonemes, discriminability increased near the voiced–voiceless boundary in a manner comparable to the full‐syllable stimuli. These data suggest that the phoneme‐boundary effect in VOT discrimination reflects a genuine increase in discriminability near the phoneme boundary. However, in agreement with the recent data of J. D. Miller and his colleagues, these results suggest further that the phoneme‐boundary effect for VOT is not due exclusively to phonetic categorization but may instead reflect acoustic and auditory properties which are distinct from phonetic processing.
Subject Classification: [43]70.30; [43]65.75; [43]70.35..
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43.70.-h Speech production
42.66.-p Physiological optics

Correlation of nonlinear orifice impedance

Ronald L. Panton and Allen L. Goldman

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1390-1396 (1976); (7 pages) | Cited 7 times

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Dimensional analysis of the orifice impedance problem produces several sets of nondimensional variables which may be used to correlate nonlinear orifice behavior. Published experimental data on thin orifices were examined and it was found that tests with oil, water, and air can be correlated. Graphs of orifice resistance are given in nondimensional forms that are useful over a wide range of conditions. The form for resistance is R/ρ (νω)1/2 as a function of an aspect ratio parameter l/d, an orifice velocity parameter V/(νω)1/2, and a diameter‐viscous parameter d/(ν/ω)1/2. For thin orifices the resistance is independent of d/(ν/ω)1/2 when this parameter is greater than 10. Nonlinear effects begin when V/(ν/ω)1/2=3. This parameter compares the displacement amplitude to the viscous diffusion length. The reactance end correction δ was normalized by the Rayliegh value of 8d/3π and correlated using the variables l/d, V/ωd, and d/(ν/ω)1/2. Again thin orifices show no dependence on d/(ν/ω)1/2 for values greater than 20 and the nonlinear reactance region begins at V/ωd=0.1. Thus, different parameters govern the onset of nonlinear resistance and reactance.
Subject Classification: [43]85.20, [43]85.50; [43]28.60.
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43.58.+z Acoustical measurements and instrumentation
43.25.-x Nonlinear acoustics
43.28.+h Aeroacoustics and atmospheric sound

Measurement of the acoustic impedance of an orifice under a turbulent boundary layer

A. L. Goldman and Ronald L. Panton

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1397-1405 (1976); (9 pages) | Cited 4 times

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The acoustic impedance of an orifice under a turbulent boundary layer was measured. A single orifice, 0.508 cm in diameter and 0.32 cm thick, was tested in a wind tunnel where the velocity was varied from 16 to 30 m/sec. An impedance tube mounted behind the orifice was operated at frequencies from 250 to 2200 Hz with sound pressure levels from 85 to 140 dB. It was found that the resistance and reactance end correction could be nondimensionalized as R/ρ (νω)1/2 and δ/δeo, respectively, and correlated as functions of l/d, ωd2/ν, u∗d/ν, and V/u∗. The symbols are R resistance, ρ density, ν kinematic viscosity, ω frequency, δ end correction, δeo linear end correction without flow, l orifice thickness, d diameter, u∗ boundary layer friction velocity, and V acoustic velocity amplitude. Nonlinear behavior occurred when V/u∗ was greater than three. Amplitudes greater than three were only obtained in the 250‐Hz tests, however, at this frequency the V/u∗≳3 criteria was independent of u∗d/ν. In the linear range R/ρ (νω)1/2 versus ωd2/ν produced U shaped curves parametrically dependent on u∗d/ν. When u∗d/ν was greater than 250 the resistance with flow was greater than the no flow for all frequencies. If u∗d/ν was less than 250 there was a frequency range where the resistance with flow was less than the no‐flow resistance. The reactance end correction as a function of these same variables gave an inverted U shape. Above u∗d/ν=250, the reactance decreases with flow for all frequencies, while below 250 there is a frequency range in which the reactance increases over the no‐flow reactance.
Subject Classification: [43]85.20; [43]28.60.
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43.58.+z Acoustical measurements and instrumentation
43.28.+h Aeroacoustics and atmospheric sound

Discrimination of pure‐tone intensities by the California sea lion

Patrick W. B. Moore and Ronald J. Schusterman

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1405-1407 (1976); (3 pages) | Cited 1 time

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On the basis of previous behavorial experiments on sound localization under water along with sound–skull measurements in water, it was hypothesized that the California sea lion (Zalophus californianus) is capable of discriminating an intensity difference of approximately 3 dB at 16 kHz. The present experiment confirmed this hypothesis by means of a series of behavorial psychophysical experiments.
Subject Classification: [43]80.50, [43]80.60.
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43.80.-n Bioacoustics

Ultrasonic propagation properties of mammalian testes

J. K. Brady, S. A. Goss, R. L. Johnston, W. D. O’Brien, Jr., and F. Dunn

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1407-1409 (1976); (3 pages)

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The ultrasonic absorption and reflection properties of sexually mature, freshly excised mouse, rabbit, cat, and dog testes have been investigated at 37°C in the frequency range 0.5–7MHz by the transient thermoelectric absorption, the pulse–reflection, and the pulse–transmission methods. The absorption coefficient is found to exhibit values considerably less than those of other parenchymal tissues and to possess a frequency dependence mimicking a simple relaxation process of characteristic frequency approximately 0.9 MHz.
Subject Classification: [43]80.20.
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43.80.-n Bioacoustics

Shear properties of mammalian tissues at low megahertz frequencies

Leon A. Frizzell, Edwin L. Carstensen, and Joseph F. Dyro

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1409-1411 (1976); (3 pages) | Cited 14 times

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Rough values for the transverse‐wave specific acoustic impedance Zs=Rs+jXs, transverse velocity of sound cs, and transverse absorption coefficient αs have been measured for canine liver, kidney, muscle tissues, and for packed red blood cells in the frequency range from 2 to 14 MHz at 25°C. The ranges of the results are Rs=700–3000 Ωmech/cm2, Xs=400–4000 Ωmech/cm2, cs=900–10 000 cm/sec, and αs=2000–30 000 np/cm. The corresponding results for shear stiffness μ1 and viscosity μ2 are μ1<107 dyn/cm2 and μ2=4–30 centipoise. At these frequencies the viscosities are orders of magnitude less than those reported at 0.5–5 kHz by Oestreicher (1951). The low impedances (viscosities) correspond to low velocities and extremely high absorption coefficients for shear waves in tissue.
Subject Classification: [43]80.20, [43]80.30.
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43.80.-n Bioacoustics

Errata: ’’Multidimensional analyses of judgments about traffic noise’’

Gregory W. Cermak and Peter C. Cornillon

J. Acoust. Soc. Am. Volume 60, Issue 6, pp. 1412-1412 (1976); (1 page)

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Abstract Unavailable
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43.10.Vx Errata
42.66.-p Physiological optics
43.50.+y Noise: its effects and control
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