bluuebunny/crossref_metadata_2025 huggingface dataset:
Annoyance and acceptability judgements of noise produced by four types of aircraft modifications
Authors: Borsky Paul N.
Published: October 2005

The effects of 32 different experimental aircraft noise conditions were judged on a 0–9 annoyance scale by 384 subjects. Noise levels accounted for half of all explained annoyance variance, with level A, close area noises, averaging 2.22 greater annoyance than distant area noises. The correlation between Leaq, and 1536 annoyance judgements was r=0.53, with five points of Leaq associated with a one point annoyance change. The overall annoyance reduction due to abatement programs was 1.43. However, annoyance with level A, after abatement, was still 6.23 compared to 7.53 for noise without abatement. While this represents substantial annoyance reduction, only one-third felt level A after abatement, was acceptable, but in level B, after abatement, annoyance was 3.99, acceptable to 80% of all residents. Annoyance under TV conditions was consistently greater than noise judgements under rest relaxation, averaging 1.02 points greater annoyance. Likewise, subjects with residence in distant areas judged all noises more annoying than close area residents, averaging 0.83 greater annoyance for level A and 0.53 greater annoyance for their own level B noise.
TTS In Squirrel monkeys to 4 kHz octave band noise of long duration
Authors: Nielsen D. W. , Turner R. G. , Fitton R. , Fowler D.
Published: October 2005

The goal of this research is to investigate the suitability of the squirrel monkey as an animal model for the effects of long duration noise exposures on humans. In our previous report [J. Acoust. Soc. Am. 60 S87(A) (1976)] we demonstrated that TTS to an octave band noise centered at 500 Hz showed growth and recovery curves similar to those reported for humans. The present study exposed six squirrel monkeys to an 85 dB SPL octave band noise centered at 4 kHz for as long as 72 h and found that the resulting TTS was less than 10 dB. This compares to a TTS of about 18 dB in humans for exposures of 8–24 h, as reported by Melnick [Effects of Noise on Hearing, edited by Henderson, Hamernik, Dosanjh, and Mills (Raven, 1976)]. When the intensity of the 4 kHz CF OBN was increased to account for differences in absolute auditory sensitivity between squirrel monkeys and humans, the resulting development and recovery of TTS was similar to humans, resulting in a shift of about 16 dB for exposures of 8–24 h. [This research was supported by a Ford Foundation grant to Henry Ford Hospital. Ms. Fitton was supported by the Department of Audiology, Wayne State University School of Medicine.]
Contralateral cueing effects in forward masking
Authors: Pastore R. E. , Freda J. S. , Barnett M. L.
Published: October 2005

Contralateral cueing procedures, which were originally developed for monaural detection under continuous masking noise [R. D. Sorkin, J. Acoust. Soc. Am. 38, 207–212 (1965); M. M. Taylor and S. Forbes, J. Acoust. Soc. Am. 46, 1519 (1969)], were recently employed to identify factors important in backward masking [J. S. Puleo and R. E. Pastore, J. Acoust. Soc. Am. 61, S1(A) (1977)]. The procedure initially involves finding contralateral cues which are effective in improving detection performance. The cues than are systematically degraded along specific dimensions in order to identify the aspects of the cue used by the observer to counteract the effects of backward (but not simultaneous) masking. This paper describes the results of applying this technique to the study of forward masking. We employed a single-interval (yes-no) detection paradigm with 20 msec segments of a sinusoid as the signal and a 15 dB, 1-sec increment in noise as the masker. The contralateral cues ranged from a phase-locked (but shifted) sinusoid to a temporal gap in a continuous noise. The patterns of cueing effectiveness for forward masking are clearly dissimilar to that reported at the last ASA Meeting for backward masking. [Research supported by a grant from NINCDS.]
Perceptual analysis of speech sounds by prelinguistic infants: A first report
Authors: Aslin R. N. , Perey A. J. , Hennesy E. , Pisoni D. B.
Published: October 2005

In this paper we report the results of an investigation that employed a two-alternative forced-choice head-turning paradigm to study speech perception abilities in 5–6-month-old infants. Two synthetically produced speech sounds were presented as training stimuli during initial shaping and conditioning phases and the infant was reinforced with the presentation of a visual stimulus (i.e., an animated toy monkey) for an appropriate differential head-turn response toward the right for one stimulus (S1) or toward the left for another stimulus (S2). Successful discrimination training was followed by a transfer phase in which generalization to a variety of novel speech sounds was measured by observing the direction of the infant's head turns. Implications of our findings and methodology for questions surrounding perceptual constancy, feature analysis and the role of early environmental experience in development of speech perception abilities in young infants will be discussed. [This work was supported by research grants from NIMH and NIH.]
A new analytical solution for the difference-frequency field of an unsaturated parametric acoustic radiator via the “quasi-optical” analogy
Authors: Fenlon F. H.
Published: October 2005

In this paper a weak finite-amplitude solution for the difference-frequency field of a parametric acoustic array is derived via the second-order nonlinear paraxial wave equation [i.e., the nonlinear optical analog established by E. A. Zabolotskaya and R. V. Khokhlov, Soy. Phys. Acoust. 15, 35–40 (1969)] by expressing the primary waves of an axisymmetrically excited bifrequency piston projector as a weighted sum of Gauss-Laguerre modes. By relating the fundamental (i.e., Gaussian) modes in the farfield of the projector to those of equivalent “Bessel beams” a new closed-form expression for the difference-frequency field is thus obtained as a function of range. A review of the solution's phenomenological properties will then be presented, followed by a brief comparison of predicted results and experimental data reported in the literature.
Six-parameter characterization and optimum design of a mass-loaded longitudinally vibrating transducer
Authors: Wang H. S. C.
Published: October 2005

Longitudinal vibrators constructed from segmented ceramic tubes have been extensively used as electroacoustic transducers of active sonar arrays. In an earlier effort, this author extended Martin's theory of vibrations of longitudinally polarized ferroelectric cylinders to the case of a practical transducer driving a radiation load via a light square piston at one end and mass loaded at the other (H. S. C. Wang, Final Technical Report, Optimum Phase Shading Technology Development and Evaluation Program. Hughes Aircraft Company, June 1977). It was demonstrated there that the driving-point admittance of such a transducer can be formulated in terms of five parameters: namely, the characteristic impedance of the ceramic tube, the time constants of the ceramic tube and the tail mass, the electromechanical transformation ratio, and the longitudinally clamped capacitance. From this formulation, with the addition of a resistance representing internal power loss as the sixth parameter, and by defining an object function. O.F. =  ∑ n=1N wn⋅|Yn − Yn(d)|, where wn is a scalar weight, Yn. and Yn(d) are the driving-point admittance and its desired value at the nth of N frequency points, an optimum transducer design procedure based on the steepest descent search for the minimum of the O.F. has been developed.
The real roots of the fluid-loaded plate
Authors: Strawderman W. A. , Ko S. H.
Published: October 2005

Recent investigations of fluid-loaded plates have suggested the possibility of three real roots for the equation governing the free wave number of fluid-loaded plates. These three real roots are purported to correspond to three separate and distinct free wave numbers for the fluid-loaded plates, a result at variance with the classical single free wave-number solution. This paper reexamines the free vibration of the fluid-loaded, thin plate to clarify this question of multiple roots. The results of this study confirm the classical single free wave-number result, and show that multiple real roots can only be obtained by violating the radiation condition. [Work supported by CNM.]
Mechanisms by which ultrasound stimulates tissue repair
Authors: Dyson M.
Published: October 2005

Experimental studies of tissue repair in animals have shown that therapeutic levels of ultrasound can increase the rate of growth of replacement tissue at sites of injury. In a controlled clinical trial, similar results were obtained when chronic varicose ulcers were treated with similar levels of ultrasound. Although local heating may be partly involved in the stimulation of repair by ultrasound, it is not the sole cause of it. Nonthermal mechanisms proposed include acoustic streaming, possibly associated with cavitation. The irradiation of fibroblasts with therapeutic levels of ultrasound at ambient pressure resulted in (a) stimulation of collagen synthesis, (b) decrease in electrophoretic mobility, (c) modification of locomotor activity, (d) temporary elevation of intracellular calcium, (e) ultrastructural changes including plasma membrane alteration and increased vacuolation. There was no change in the viability of the fibroblasts. All the changes found were suppressed in matched cell samples irradiated in the same manner at elevated pressure, suggesting the involvement of cavitation. The cellular effects described are consistent with those expected to be associated with the enhancement of tissue repair. [Work supported by SRC and Guy's Arthritis Research Unit.]
Effects of pulsed ultrasound on the choroid and retina
Authors: Lizzi F. L. , Driller J. , Coleman D. J. , Franzen L. , Leopold M.
Published: October 2005

Lesions were produced in the retina, choroid, and sclera using continuous and pulsed ultrasound of high average intensity. Anesthetized rabbits were exposed to 9.8-MHz focused ultrasound at intensities ranging up to 1500 W/cm2. Follow-up techniques included cine- and still-fundus photography, fluorescein angiography, and histology. Exposure durations ranged from 0.01 to 20 s. Two distinct regimes of pulsed ultrasound were studied. The first employed relatively long ultrasonic pulses (50 ms and longer) delivered at low repetition frequencies (10 Hz and less). Insonification produced pulsatile choroidal blanching and recovery which were documented with cine-fundus photography. The apparent mechanism is pulsatile radiation force exerted on the choroid. The second pulsing regime consisted of much shorter pulse durations (e.g., 50 μs) delivered at elevated pulse repetition frequencies (e.g., 10 kHz). The time-averaged intensity levels required for production of chorioretinal lesions are close to those required with exposure to continuous wave ultrasound. Thermal effects were indicated to be the major mechanism of permanent chorioretinal lesion formation with both continuous and pulsed insonificalions. The lesions and requisite exposures are similar in several respects to those produced with laser photocoagulators. The chorio-retinal studies are providing the data base needed to explore the safe exploration of therapeutic ultrasound. One promising application is indicated in preliminary results demonstrating accelerated resorption of intravitreal membranes in rabbits.
Relation of loudness to intensity discrimination
Authors: Braida L. D. , Durlach N. I.
Published: October 2005

One outgrowth of our theory of intensity resolution is the following prediction concerning the relation of loudness matches to intensity discrimination: Two stimuli are matched in loudness if and only if their intensities divide their respective dynamic ranges proportionately in terms of number of JNDs [J. S. Lim, W. M. Rabinowitz, L. D. Braida, and N. I. Durlach, J. Acoust. Soc. Am. 62, 1256–1267 (1977)]. This prediction, which is essentially the same as that proposed by Riesz [R. R. Riesz, J. Acoust. Soc. Am. 5, 211–216 (1932)], is derived from our theory by assuming that loudness is the predominant cue used to discriminate intensity and that all stimuli are equally loud at the tops and bottoms of their dynamic ranges. This prediction is consistent with a wide variety of functions relating loudness to intensity (including the power law); all that is required is that loudness be a monotonically increasing function of the proportional JND factor and that this function be the same for all stimuli. This prediction does not, however, take account of the effects of context on loudness. In this paper, we discuss this prediction in detail and comment on its relation to other concepts concerning discrimination and loudness and on its consistency with experimental data. [Work supported by NIH and NSF.]
Loudness and annoyance of single and combined community noises
Authors: Berglund B. , Berglund U.
Published: October 2005

The contribution of type and levels of community noises to the perception of loudness, noisiness, and annoyance is being explored in ongoing research projects. Particular attention has been given to the relationship between scaling method and the conclusions it is possible to draw from the data, especially with regard to observers' abilities to differentiate noises according to the above attributes. Procedures for calibrating and possibly standardizing the perceptual scales have been attempted with preliminary success. Various types of noises have been investigated: aircraft noise under different flying conditions, traffic noise, and a number of other community noises. Besides specific scaling problems, the investigations have addressed the specific problems of observers' abilities to differentiate among noises that are combined in a complex setting as well as their ability to integrate various noises into a unitary perception of loudness and annoyance. Since the experimental setups reflect real-life situations, the answers to these latter questions are relevant to understanding the responses of the individual who is exposed to combinations of noises in his or her community.
The annoyance of sound and of other life events
Authors: Galanter Eugene
Published: October 2005

Scaling annoyance is different from scaling loudness. The exponent of the annoyance function is more labile than the exponent of the loudness function. However, there is a general truth: If one physical parameter is varied then subjects will use those variations to represent values of the dimension they are asked to respond to. This clearly induces correlations between things like annoyance and loudness.They can only be untangled when annoyance judgments vary, as with spectral differences, but loudness does not. Not only are scales of annoyance different from perceptual scales, the notion of “annoyance” derives from a social response to noise. Community response is commonly represented by proportions of respondents replying to partition scale descriptors. Evidence that community annoyance is not represented by such frequency tables is shown by the discrepancy between survey response data for attitudes toward the Concorde, and the annoyance scales for aircraft overflight sounds based on a utility comparison scale (cross-modality matching). These data demonstrate that although everyone in a community may report that they are annoyed by the sounds of aircraft overflights, the magnitude of the annoyance is neither uniform across individuals, nor is it reflected in the proportions of annoyed people in the community. [Work supported by NASA.]
Listener ratings of loudness and effort for selected speech samples
Authors: Spencer L. E. , Counihan D. T.
Published: October 2005

This study investigated relationships among two types of speech samples and ratings of loudness and of effort. Four adult speakers individually produced the vowels/a/ and /i/ and a sentence at 65, 75, and 85 dB SPL. The vowels were produced first with fundamental vocal frequency varying with intensity, and then with frequency controlled. The samples were then made into listening tapes. The intensity of each taped sample was electronically altered to allow listeners to hear each production at each of three different playback intensities. The taped samples were rated for loudness and for effort using the method of magnitude estimation. For both types of speech sample, increments in playback level resulted in nearly linear increments in rated loudness and effort. Effort ratings increased in nearly linear fashion as a function of production intensity for sentences but not for vowels. The effects of vowel identity and frequency condition were highly speaker dependent.
Variability in magnitude estimation
Authors: Green David M.
Published: October 2005

Variability in magnitude estimates, both within and among observers, will be discussed. Over a group of 20 subjects the power-law exponents may vary from 0.1 to 0.4 (power units). Repeated judgments for a single individual of a given intensity show coefficients of variation (ratio of standard deviation to mean) of 0.1–0.4. Magnitude production data show similar values. Although such variability has been known to exist for some time, there is still no adequate theory to account for it nor empirical techniques to minimize it. For practical application of this technique there is no alternative but to use large numbers of subjects. [Work supported by NIH.]
The perception of voice onset time in Polish
Authors: Mikoś Michael , Keating Patricia , Moslin Barbara
Published: October 2005

Polish is traditionally described as using the prevoiced and short-lag categories to contrast its voiced and voiceless stops. However, Moslin and Keating [J. Acoust. Soc. Am. 62, S27 (A) (1977)] have shown that some speakers of Polish make use of the long-lag, aspirated voicing category. Preliminary results for six speakers of Polish on a/da/-/ta/continuum with VOT from −20 to +80 ms indicate that all speakers, regardless of how they produce their apical stops, show a labeling boundary and discrimination peak at about 35 ms. That is, speakers who rarely if ever produce long-lag stops themselves place their category boundary between the short- and long-lag regions, thus showing a dissociation between production and perception. Further work will vary the test conditions and/or subjects' response categories to determine if a boundary exists between the prevoiced and short-lag regions of the continuum.
Learning and generalization of intraphonemic VOT discrimination
Authors: Edman Thomas R. , Soil Sigfrid D. , Widin Gregory P.
Published: October 2005

A recent study [A. E. Carney, G. P. Widin, and N. F. Viemeister, J. Acoust. Soc. Am. 62, 961–970 (1977)] has shown that with appropriate training listeners can consistently discriminate intraphonemic differences in a synthetic bilabial VOT stop consonant series. We examined whether listeners trained to discriminate intraphonemic differences on one VOT series can also make intraphonemic discriminations on a different VOT series. Identification and discrimination data were initially obtained from a group of six listeners for both a bilabial and a velar VOT stop consonant series. Half the listeners then received discrimination training on the bilabial series and half received training on the velar series. Discrimination and identification data were subsequently obtained from all listeners for both series. Improved final discrimination on the nontraining series indicates that listeners had learned to discriminate VOT per se, while a failure to improve discrimination on the nontraining series indicates that specific properties of the training series had been learned. [Supported by NIMH, NICHD.]
Poststimulatory and perstimulatory effects in single auditory-nerve fibers: Some common properties
Authors: Smith R. L.
Published: October 2005

The following equation summarizes many of the poststimulatory and perstimulatory effects of a short-term conditioning tone on the response to a brief test tone: R(i,I,T,t) = F(i) − [F(I) − SP]G(T,t). R represents the firing rate in response to the test tone; i and I, the sound intensities of the test and conditioning tones, respectively; F, the unconditioned or unadapted rate-intensity function; and SP, spontaneous activity. The “relative decrement” G depends on both the duration of the conditioning tone T, and the silent interval between the conditioning and test tones, t. In the perstimulatory paradigm t = 0, R represents the total response during the test interval, and i, the total intensity. According to the equation, the response to the test tone equals the unconditioned response minus the decrement produced by the conditioning tone. Furthermore, the decrement is proportional to the driven response to the conditioning tone and does not depend on sound intensity per se. The experimental results leading to these conclusions will be reviewed, as will their physiological and psychophysical implications.
Some observations on how the perception of syllable-initial [b] versus [w] is affected by the remainder of the syllable
Authors: Miller Joanne L. , Liberman Alvin M.
Published: October 2005

Given a distinction between [ba] and [wa] in absolute syllable-initial position cued by duration of formant transitions, we ask how the distinction is affected by that which occurs later in the syllable. In one experiment, we varied the duration of the steady-state formants that followed the initial transitions, producing syllables with overall durations in the range of 100–370 ms. The observed consequence was a shift of about 20 ms in the duration of formant transitions required to convert [ba] to [wa]: The longer the syllable, the longer the formant transition necessary to perceive [wa]. In a second experiment, we attached formant transitions to the end of the syllable in such a way as to produce the syllable-final stop [d], hence the syllables [bad] or [wad]. This maneuver had an effect precisely opposite to that we had obtained when we lengthened the syllable by adding steady-state formants. That is, adding formant transitions to the end of the syllable, thus creating [bad-wad], had the same effect on the perception of syllable-initial [b-w] as subtracting a certain duration of steady-state formants from [ba-wa]. We suppose that in these cases the subsequent information in the syllable specifies the rate at which the speaker is talking, and we take the effect on syllable-initial [b-w] to be the listener's adjustment to that rate. Certain aspects of these data are in accord with findings of Minifie, Kuhl, and Stecher [J. Acoust. Soc. Am. 62, S15(A) (1977)] and Summerfield (in preparation). [Work supported by NIH.]
Airframe aerodynamic noise—total radiated acoustic power approach
Authors: Shaw L. L. , Houser D. R.
Published: October 2005

During flight the noise radiated by aircraft is emanating from two distinct types of sources. One source is the propulsion system and the other is the nonpropulsion system noise, or airframe noise, associated with movement of the aircraft through the atmosphere. The purpose of this effort was to study airframe noise using a total radiated acoustic power approach. Methodology was developed to accurately calculate the total acoustic power by using measurements from an array of microphones during aircraft flyover. This methodology was applied to Schweizer 2–32 glider flyovers and it was found that for an aerodynamic configuration (no flaps, wheels, wheel wells, etc.) the total acoustic power can be obtained from one flyover measurement by assuming the directivity is nearly equal in all directions. This assumption was shown to be valid for the glider and is assumed valid for any aircraft in an aerodynamic configuration. The detailed methodology developed is still useful since most commercial aircraft land in a nonaerodynamic configuration and thus their directivity is not equal in all directions. The results from the glider tests were compared to data in the literature and found to agree well. Variation of the total power with aircraft velocity followed a V6 law. The parameter which best normalizes the overall acoustic power from different aircraft was found to be the wing area.
Measurements of noise of centrifugal fans by flush-mounted microphones inside the exhaust ducts
Authors: Krishnappa G.
Published: October 2005

There are no existing standards on measurements of noise radiated by fans and blowers inside small exhaust ducts. Noise measurements by in-duct flush-mounted microphones are likely to be affected by pressure fluctuations caused by the presence of the turbulent boundary layer along the duct. By using cross-correlation techniques, the validity of such measurements are examined in this paper. Noise signals produced by several impellers of 203-mm diameter operating inside two different casing configurations were measured in a centrifugal fan noise test rig containing a long 50-mm-diameter exhaust duct, with an anechoic termination. The signals from two flush-mounted microphones separated by a distance of 1.22 m were cross correlated at several fan speeds and flow velocities. There were good correlations observed between the two microphone signals at low flow velocities for the time interval corresponding to the acoustic velocity. Although at higher flow velocities the correlation between the two overall signals was poor, encouraging correlations were obtained for the filtered signals in octave bands at frequencies above 125 Hz.
Calibration of “half-inch” condenser microphones: Comparison of selected electrostatic actuator methods with measurement of pressure response in ANSI couplers
Authors: Nedzelnitsky V. , Penzes W. B. , Lalli F. P.
Published: October 2005

Coupler techniques based upon reciprocity are generally considered the most accurate method for absolute pressure calibration of laboratory microphones. Electrostatic actuator techniques are convenient and widely used for obtaining the relative frequency-response levels of such microphones. However, actuator-determined response levels can differ appreciably from the pressure-response level because the electrostatically induced motion of a microphone diaphragm is influenced by the relation between its own acoustic impedance and the radiation impedance with which it is loaded. To evaluate the magnitude of this difference in some practical situations, microphones of different nominal equivalent volumes and resonant frequencies were calibrated in standard couplers (ANSI S1.10-1966, R1971) over the frequency range 50–20 000 Hz. Response levels for these microphones were determined with electrostatic actuators and normalized to coincide, at 700 Hz, with the coupler-determined response levels. Differences between the normalized actuator-determined levels and the coupler-determined levels were usually largest at frequencies above 5 kHz and were dependent upon actuator configuration and microphone type. Differences of less than 0.3 dB could be found for microphones of high nominal resonant frequency and low nominal equivalent volume, but greater differences (e.g., 1 dB) could be observed for microphones of low resonant frequency and high equivalent volume.
Acoustic power spectra due to multiple rough surface scattering
Authors: Beilis A. , Tappert F. D.
Published: October 2005

The previously derived master equations [J. Acoust. Soc. Am. 62, A181 (1977)] describing the second-order statistics of normal mode amplitudes due to energy transfer between modes caused by multiple rough surface scattering have been generalized to include quasistatic time-dependent effects. We obtain a new system of master equations for the quantities 〈an(r,t)an*(r, t + τ)〉, where the an(r,t) are the normal mode amplitudes. We then construct 〈p(r,z,t)p*(r, z, t + τ)〉 by incoherently summing the modes. The Fourier transform (with respect to τ) of this quantity gives the sideband spectra of the pressure signal as a function of range and depth. We find that the spectra are symmetric (asymmetric) according to whether the surface wave spectrum is even (odd) with respect to the horizontal wave number in the direction of propagation. Numerical examples of spectra will be presented. [Work supported by ONR.]
A parabolic coherence function propagation model for moderately broadband signals
Authors: McCoy J. J. , Beran M. J.
Published: October 2005

The propagation model is formulated in terms of a field measure that is denoted by {Γ̄(x,t,θ,ω)}. This measure provides a decomposition, with respect to both direction and frequency, of the averaged energy flux through an elemental aperture located by x during an elemental time interval determined by t. The propagation model is an extension of one previously presented by the authors [J. Acoust. Soc. Am. 57, S64(A) (1975); 59, 1142–1149 (1976)], which is applicable for narrow-band (or cw) signals. The model is applicable for moving sources and for a time-varying ocean.
Mode coupling in a sound channel with range-dependent velocity profile
Authors: Chwieroth F. S. , Nagl A. , Überall H. , Zarur G. L.
Published: October 2005

The sound propagation problem is considered for an ocean environment with arbitrary range as well as depth dependence. The ocean bottom is permitted to have a gradual slope. For these conditions the wave equation reduces to a set of coupled differential equations for the range dependence. The ocean is segmented both horizontally and vertically. Within each segment the sound speed is taken to vary linearly with both depth and range. The depth equation is first solved at each vertical boundary to yield depth functions which have the form of Airy functions. The coupled range equations are recast into a set of uncoupled equations through a series of transformations: for this purpose the minor range dependence within a given segment of the depth functions has been neglected. The solution to the original coupled equations is found by applying the inverse transformations to the decoupled solution. The effect on the transmission loss of including the coupling terms is considered. Profiles with different horizontal gradients are considered to determine when the full treatment of the wave equation is necessary. The energy transfer between the modes is also examined. [A. N. and H. Ü. were supported by NRL code 8120.]
Strong scattering in the ocean: Validity of the stochastic wave equation
Authors: Breton I. J. Raymond , Middleton David
Published: October 2005

Although the stochastic wave equation enjoys a central place in acoustic research, the circumstances under which it is valid are not well understood. Previous attempts to fix the bounds of validity have yielded two criteria [J. A. Neubert and J. L. Lumley, J. Acoust. Soc. Am. 48, 1212–1218 (1970)]. We augment and complete the list of criteria which must be met (there are some 16 criteria in all). The criteria include considerations of frequency, propagation velocity, motion of the medium, gravity, losses, density, and turbulent pressure. Researchers and experimenters may use the criteria as a rapid and quantitative means of verifying that a given situation may be correctly modeled by the wave equation.
Numerical solutions of underwater acoustic wave propagation problems
Authors: Lee D. , Papadakis J. S. , DiNapoli F. R.
Published: October 2005

Two accurate and general purpose numerical approaches are presented for the solution of variable-coefficient parabolic wave equations. (1) An Ordinary Differential Equation Approach: The parabolic equation is treated as a system of ordinary differential equations where the second partial derivative with respect to the space variable is discretized by means of a second-order central difference. Nonlinear Multistep (NLMS) methods are used as predictor and corrector for solving this system. A variable-step-size technique is built in to give the desired accuracy. The theory with regard to consistency, stability, and convergence has been very well developed for NLMS methods thus ensuring the convergence of this procedure. (2) A Finite-Difference Approach: A finite-difference technique is derived from the conventional implicit schemes. This technique is proved to be convergent in theory and is found to be general purpose and provides reasonable accuracy. The solution of a range-dependent problem with nonflat bottom will be discussed as a demonstration of the validity of these approaches. In addition, the relative merits and disadvantages will also be discussed.
Absence of biochemical effects in cells and tissues of ultrasonic irradiation of mice and of the in vitro irradiation of mouse peritoneal and human amniotic cells
Authors: Glick D. , Adamovics A. , Edmonds P. D. , Taenzer J. C.
Published: October 2005

Cyclic AMP, cyclic GMP, and histamine concentrations were determined in skin, lung, and peritoneal cells of mice, untreated, sham-treated, and treated, in vivo (1 W/cm2, 100 and 200 s), mice killed and samples taken 2–120 min after exposure. Similar experiments, also with liver, were performed with focused-beam exposures (2-MHz continuous wave, 8.4 W/cm2, 2 × 100 s; 10 W/cm2, 12 s) of areas of the mouse. In addition, wide-beam exposures, in vitro, of the peritoneal cells and human amniotic cells were included. In all of the work, no significant effect of the exposures was observed in comparison with the controls. Furthermore the percent of dead peritoneal and amniotic cells present was not affected by the exposures. These results may depend on maintenance of the integrity of the cell membranes during the exposures, in spite of the damage to other cell structures. [Research supported by the National Institute of General Medical Sciences, Grant No. GM 22684.]
Ultrasonic radiation on fecundity of mouse from testicular exposure (preliminary report)
Authors: Januzik S. J. , O'Brien W. D.
Published: October 2005

It has been shown that ultrasonic radiation causes morphological alteration to mouse testicular tissues, thus posing the question of male fecundity postirradiation. Three groups of 6-month-old LAF1/J mice (Jackson Labs) were studied viz. an irradiated group, (exposed to 1-MHz cw ultrasound with spatial peak intensity 10 W/cm2 for 30 s), a sham irradiated group (prepared identically to that of the irradiation group but not exposed), and a control group (animals did not leave the animal room). For the sham and irradiated groups both testes were ligated and sequentially exposed by positioning the beam axis in the center of each testis. The half-power beamwidth was 10 mm and the approximate length of the mouse testis is 7 mm. Upon recovering from the gaseous anesthesia each mouse was placed in a cage with three normal, proven females and the resulting litters were scored over a six-month period. A plot of the cumulative pups per female versus time was made for each group and a linear regression analysis was performed to obtain the best-fit straight line. The time intercept indicates the time coitus is initiated and the slope may be considered a measure of male fecundity. Though the control and sham groups had virtually the same slope, their time intercepts differed, indicating an approximate eight-day delay in initial coitus for the shams. The irradiated group showed an increased delay in coitus initiation to 11 days and a lesser slope suggesting a decrease in mating capability post-irradiation. These preliminary results suggest that ultrasound affects the males' recovery immediately following the irradiation procedure and some aspects of spermatogenesis. [Work supported in part by FDA.]
Fetal brain weight reduction following ultrasonic exposure in guinea pigs
Authors: Ziskin M. C. , Barnett S. B. , Edwards M. J.
Published: October 2005

Pregnant guinea pigs were exposed to ultrasound at intensities varying from 0 to 1.1 W/cm2. Each exposure was 1 h in duration. Following delivery, the offspring were evaluated for litter size, body weight, and brain weight. The ratio of brain weight to body weight was the most sensitive indication of biological damage. Reduction in brain weight correlated, not with ultrasonic intensity, but with intra-abdominal temperature elevation measured during the exposure. The bioeffect noted is the same as that resulting when hyperthermia is induced in pregnant guinea pigs without ultrasonic exposure. [Work supported in part by a Research and Study Leave from Temple University.]
Effects of ultrasound on transport in avian erythrocytes
Authors: Bundy M. L. , Lerner J. , Messier D. L. , Rooney J. A.
Published: October 2005

A 1-MHz continuous wave sound field of intensity 0.6 W/cm2 was applied to a suspension of avian erythrocytes in vitro for 30 min. Total uptake (diffusion plus nonspecific binding plus mediated transport) was determined by incubation of 1-ml aliquots of insonated and control cells for 10 min in labeled leucine. The percentage of the total uptake due to mediated transport was determined by a similar incubation in a 50:1 mixture of the competitive inhibitor isoleucine and labeled leucine. At the intensities used the sonated cells absorbed approximately 5% less labeled leucine than the control cells. Analysis shows the effect to be statistically significant (P < 0.01). However, results for the effect of ultrasound on mediated transport are not statistically significant (P > 0.9). Therefore, the greatest effect of ultrasound using these experimental conditions is on the diffusion component of transport. [This work was supported in part by the American Heart Association-Maine Affiliate, NIH via AM 19445 and the Maine State Experiment Station.]
Effects of ultrasonically produced shearing stresses on enzyme systems
Authors: Kashkooli H. A. , Rooney J. A. , Roxby R.
Published: October 2005

Solutions of the enzymes catalase and malate dehydrogenase have been exposed to ultrasonically produced shearing stresses for period of up to 90 min. These enzymes were sonated by placing a resonant length of tungsten wire into a 0.3-ml sample and driving the wire in transverse oscillation at 20 KHz. After sonation, the enzyme activity was determined spectrophotometrically. Catalase was not inactivated under any of the experimental conditions used. Malate dehydrogenase was found to be inactivated for wire displacements greater than 30 μm. Since no temperature rise or cavitation were detected in the treatment vessel, the mechanism for inactivation is believed to be shearing stresses associated with acoustic micro-streaming. For conditions of the experiment, the magnitude and duration of the shearing stress are, respectively, 3000 dyn/cm2 and 2 ms. The enzyme was inactivated at an exponential rate which was inversely proportional to enzyme concentration. [This work was supported in part by the American Heart Association-Maine Affiliate.]
Ultrasonic velocity and qualitative appearance of fresh and fixed liver tissue with acoustic microscopy
Authors: O'Brien W. D.
Published: October 2005

Mouse liver tissue (10 month, female, LAF/J) was studied under the scanning laser acoustic microscope (SONOMICROSCOPE 100®) operating at an ultrasonic frequency of 100 MHz. The liver specimens were prepared as followed: (1) fresh samples examined within 45 min following animal sacrifice, (2) fixed in balanced saline and formalin for 48 h, (3) fixed in Bouin's fluid for 24 h, and (4) fixed by boiling in a physiological salt saline for 70 s. The ultrasonic velocity in the fresh specimens was 1605 m/s (±1.5%). The specimens fixed in the formalin solution and boiling saline yielded velocities within the range of fresh tissue whereas those fixed in Bouin's fluid had velocities about 5% greater. Qualitatively, specimens fixed in Bouin's fluid and formalin solution had acoustic micrographs similar in appearance, viz., relatively homogeneous in appearance, well-defined edges, and relatively opaque. Fresh specimens also appeared relatively homogeneous, had poor edge definition and were rather acoustically translucent. The specimens prepared in the boiling saline exhibited a rather coarse appearance, had edges not as well defined as the other fixed specimens and exhibited transmissivity of sound between that of the other fixed specimens and the fresh specimens. [Work supported in part by NSF.]
Psychophysical tuning curves: The width of the signal's excitation pattern
Authors: Johnson-Davies David , Patterson Roy D.
Published: October 2005

The interpretation of psychophysical tuning curves depends on the assumption that the width of the signal's excitation pattern is negligible. To test this a second masker, with a level 10 or 15 dB below the tuning curve, was positioned either 200 Hz above or 200 Hz below the signal on the side away from the primary masker. The signal was a 2.0-kHz tone with a level of 20 dB SPL (approximately 18 dB SL) and a duration of 500 ms, the maskers were 100-Hz-wide narrow-band noises, and the signal and maskers were presented simultaneously. Whereas the second masker should have had no effect, it actually increased the effectiveness of the primary masker by up to 21 dB. This suggests that previous psychophysical tuning curves have been artificially narrow and indicates that even when the signal is as low in level as 20 dB the width of its excitation pattern is an important factor. [D.J.D. was supported by a SRC studentship.]
Analysis of some factors influencing frequency discrimination
Authors: Rakowski Andrzej , Jaroszewski Antoni
Published: October 2005

The performance of very experienced listeners in frequency discrimination tasks is markedly improved in a time paradigm with very short interstimulus intervals and symmetrical alternation of stimuli. The improvement for shortening interstimulus time intervals from 500 to 25 ms is a factor larger than 2, and frequency differences of 0.4 Hz at 1000 Hz are consistently detected. There are two possible sources of such improvement: properties of short-term memory, and various forms of mutual interaction of the stimuli. A series of experiments has been performed in order to establish the order of importance of separate factors. It has been found that avoidance of perceptual interference and benefiting from poststimulatory pitch shift are mainly responsible for the observed phenomena.
Suppression of backward and forward masking
Authors: Weber Daniel L.
Published: October 2005

The nonsimultaneous masking of a sinusoidal signal (2 kHz) produced by a critical-band noise (200 Hz wide centered at 2 kHz) is reduced by the presence of a suppressor (bandpass noise, 2300–3700 Hz) during the masker interval. The results of various experiments suggest: (1) Suppression is greater in backward masking than in forward masking. (2) The effect of masker intensity on suppression differs in backward and forward masking. (3) If the suppressor is presented to the contralateral ear, suppression is observed in backward masking but not in forward masking. These experimental differences may reflect a fundamental difference in the processes underlying backward and forward masking. (4) The amount of masking decreases with an increase in the duration of the suppressor. It also decreases with an increase in the duration of a reduction in the intensity of the excitor presented alone. However, this change in masking is markedly different for the two conditions; the effect of the suppressor is not simply to reduce the effective level of the excitor. [Research supported by NIH.]
Integration of duration and frequency cues in discrimination between pure tones
Authors: Espinoza-Varas Blas
Published: October 2005

The acoustic cues that underlie discrimination of complex sounds (e.g., speech) are often multidimensional and sequential (i.e., not all the dimensions vary at the same time). In this work we explored whether the information provided by the various dimensions can be integrated to improve discrimination, for the case of cues consisting of a change in duration followed by a change in frequency. The procedure was a same-different discrimination between pairs of tones. Each pair consisted of two 80-ms, 1500-Hz tone bursts separated by a 60-ms interval. For the “different” trials, the comparison pair contained increments in the duration (Δt) of the first tone and/or in the frequency (Δf) of the second tone. For various values of Δt, the value of Δf required to maintain a constant performance level was measured, and vice versa. A tradeoff between the values of Δt and Δf required for d′ = 2.0 was observed, suggesting that the effects of the two dimensions were integrated. The tradeoff was most prominent when the increments in duration and frequency were matched in terms of their discriminability. The results are compared with the prediction that d′Δt+Δf = [dΔt′2 + dΔf′2]1/2. [Work supported by NINCDS.]
Further observations on speech preparatory activity of the jaw
Authors: Hamlet S. L. , Stone M. , Cullison B. , Schoner L.
Published: October 2005

In a previous paper [S. L. Hamlet and M. Stone, J. Acoust. Soc. Am. 59, S85(A) (1976)] preliminary observations were reported on the relationship between jaw openness prior to speech onset and jaw positions for vowels later in the sentence. Significant correlations between these measures were found. An additional study was undertaken to systematically examine prespeech jaw activity for single words and sentences in relation to jaw activity following acoustical speech onset. Recordings were made while subjects spoke with two different thicknesses of dental prostheses; an experimental procedure which acts to increase the variance in jaw displacements, and thus to better reveal correspondences between prespeech and later jaw positions. Physiological data were obtained using a strain gauge jaw motion transducer. Both jaw displacement and velocity were studied—velocity obtained by analog differentiation of the displacement signal. A prespeech plateau position of the jaw was identified by determining the last velocity zero before the jaw moved into the position for the initial sound. This point occurred on the order of 250 ms before acoustical speech onset. Maximum velocity in the approach to the first sound was also analyzed relative to closing and opening velocities found later in the utterances. Results are interpreted relative to the nature of anticipatory coarticulation and the extent of preplanning of an utterance. [Work supported by NIDR grant DE-03631.]
Study of tongue-jaw coordination: Possible role of tongue-hard palate contact in vowel production
Authors: Chuang Chiu-Kuang , Abbs James H. , Netsell Ronald
Published: October 2005

The inferior-superior displacement of the mandible and tongue were measured photoelectrically (Chuang and Wang, ASA 58.1) during isolated production of [i.e., u, o, and ɑ]. Correlations were calculated between tongue elevation (measured with a mandibular reference) and jaw elevation as an index of their compensatory coordination. Variability of tongue and jaw positioning was obtained as a measure of articulatory precision. The correlations for high and midvowels consistently revealed moderate-to-high negative values, while the low vowels did not show this trend as clearly. The tongue height variation was found to be extremely small for high and midvowels with 0.7-mm deviation on the average, with seven subjects, while the low and back vowels produced variation three to five times greater. With devocalized vowel gestures the correlation and variability values were essentially unchanged. One interpretation of these results was that tongue-hard palate contact provides an external spatial reference for control of high-vowel tongue and jaw positioning, while no such reference is available for low-vowel production. That is, the compensatory control of tongue and jaw movements. or motor equivalence, may be dependent upon receptors in addition to intrinsic muscle receptors for high vowels. This interpretation would be consistent with the lip and jaw coordination reported for consonant articulation. [Work supported by NIH grant NS 13274.]