bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency and amplitude perturbation analysis of electroglottograph during sustained phonation
Authors: Haji Tomoyuki , Horiguchi Satoshi , Baer Thomas , Gould Wilbur J.
Published: October 2005

Electroglottography (EGG) was used to monitor vocal fold vibration patterns in normal subjects and patients with various laryngeal disorders. In order to evaluate the regularity of vocal fold vibration, frequency and amplitude perturbation of EGG waves during sustained phonation were measured with a laboratory computer. The data were compared to the degree of hoarseness evaluated by auditory perception and by sound spectrographic analysis. Frequency and amplitude perturbation measures showed some overlap between normal and pathological groups. However, there was a close relation between perturbation analysis of EGG waves and degree of hoarseness (Spearman’s rank correlation coefficient rs=0.73, p<0.0005). Amplitude perturbation was found to be a more sensitive measure of the irregularity of vocal fold vibration than frequency perturbation.
Loudness reduction and adaptation induced by a contralateral tone
Authors: Botte M.-C. , Baruch C. , Scharf B.
Published: October 2005

An intermittent tone in one ear may induce a large decline in the loudness of a continuous tone in the contralateral ear [Botte et al., J. Acoust. Soc. Am. 72, 727–739 (1982)]. To uncover the basis for this induced loudness adaptation, the method of successive magnitude estimations was used to measure the loudness of a test tone in one ear during and after a single presentation of a brief inducer tone in the contralateral ear. Duration and frequency of the inducer were varied. The frequency of the test tone was set at 500, 1000, or 3000 Hz. Both inducer and test tones were at 60 dB SPL. When the inducer lasted 5 s or more and was at the same frequency as the test tone, the loudness of the test tone was reduced by 80% to 100% while the inducer was on. As the inducer frequency moved away from the test tone, the loudness reduction declined gradually except for a more marked drop at the point where the frequency separation exceeded the critical bandwidth. Loudness remained depressed after the inducer went off. Additional measurements showed that the amount of loudness reduction corresponded closely to the measured movement of the inducer’s sound image away from the center of the listener’s head (decentralization).
A ρc hydrophone
Authors: Moffett Mark B. , Powers James M. , McGrath John C.
Published: October 2005

Because traditional piezoelectric materials have much higher acoustic impedances than water, most hydrophones are ‘‘hard’’ compared to the surrounding water medium. This hardness causes internal and external reflections that manifest themselves as resonance and diffraction effects, respectively. Even nonvoided polyvinylidene fluoride (PVDF), a piezoelectric polymer, has a characteristic acoustic impedance, ρoco, about 2.7 times that of water. With the advent of voided PVDF, however, it is possible to match water’s impedance as closely as desired. Using ρc window material and ρc PVDF, we have constructed a ρc hydrophone whose response is essentially free of resonance and diffraction effects.
The acoustical significance of tongue, lip, and larynx maneuvers in rounded palatal vowels
Authors: Wood Sidney
Published: October 2005

The acoustical consequences of articulatory maneuvers of [y] are studied in model experiments in order to obtain insights into articulator programming and speech motor control by elucidating the role of each component maneuver of a speech segment in setting up vocal tract resonance conditions for the spectral features of the speech wave. The maneuvers of [y] are found to provide a maximum and stable plain–flat spectral contrast with [i]. The results can be generalized to different vocal tract sizes. Tongue retraction and larynx depression are rejected as compensations to counteract labial undershoot. Larynx depression is complementary to lip rounding and restores spectral sensitivity to palatal and pharyngeal tongue movements otherwise disturbed by the labial activity. Spectral sensitivity then remains the same for [i] and [y], and there is no need for separate compensation programs for each of these phones.
Profile analysis and background noise
Authors: Green David M. , Forrest Timothy G.
Published: October 2005

Spectral shape discrimination, or profile analysis, of complex waveforms (21 components) in the presence of broadband noise and special sinusoidal maskers of random amplitude was studied. The first experiment involved the discrimination between a standard flat spectrum and a ‘‘rippled’’ spectrum in broadband noise of different spectrum levels. Thresholds obtained under control conditions, without noise or without a standard, were used to estimate constants of an equation that predict thresholds where standard and noise are both present. The model assumes an external variance, produced by the noise, is added linearly to an internal variance caused by the flat standard. The mean squared error is less than 2 dB. The second experiment involved the detection of an increment on the center component of the 21-component standard. Added to the standard was an additional masking sinusoid of random amplitude. Both the frequency and the range of the random amplitude were varied and both showed a systematic influence on the detectability of the 1000-Hz increment.
Interaction between weak and short waves in a one-dimensional inhomogeneous nonlinear elastic material
Authors: Sugiyama Masaru
Published: October 2005

A wave composed of weak and short waves (WS waves) in a dynamically deformed elastic material is studied theoretically by using quasigeometrical acoustics. The material considered is one dimensional and inhomogeneous with a nonlinear stress–strain relation. A general theory for analyzing the composite wave is exploited. It is shown to the second-order approximation that the analysis of the composite wave can essentially be reduced to the analysis of a single WS wave. As an example of the general theory, a head-on collision between two WS waves is investigated.
The acoustic limit in the null-field approach to elastodynamic scattering
Authors: Olsson Peter
Published: October 2005

The limit of a vanishing shear modulus in the null-field approach to elastodynamic scattering by bounded scatterers is investigated. It is demonstrated, for a fairly large class of surfaces and for several types of boundary conditions, that the coupling between the incident and scattered P waves tends to that of a corresponding acoustic scattering problem. However, by explicit examples it is also demonstrated that the P–S coupling does not in general tend to zero rapidly enough for the amplitude of the scattered S wave to vanish pointwise in this limit; there remains a nonzero amplitude of a wave whose wavelength goes to zero.
Asymptotic analysis of nonspecular effects for the reflection and the transmission of a Gaussian acoustic beam incident on a solid plate
Authors: Rousseau M. , Gatignol Ph.
Published: October 2005

Experimental studies on the reflection and transmission of bounded acoustic beams at a liquid–solid plate–liquid interface show that, for incidences at or near the Lamb angles, some effects occur which are similar to those reported at a liquid–solid interface for the Rayleigh incidence. Theoretical descriptions of this phenomenon have been proposed that are based upon asymptotic considerations for the reflected beam and numerical considerations for the reflected and the transmitted beams. These previous theories are extended in this work. The reflected and transmitted Gaussian beams are described through a short wave asymptotic analysis in regions which are not restricted to the interfaces. The nonspecular effects which appear in the transmitted field composition are different according to whether the Lamb mode under consideration is symmetric or antisymmetric. The particular case when two Lamb modes are simultaneously excited is also studied. If the two modes have a different nature, the nonspecular effects are added while, for two modes of same nature (symmetric or antisymmetric), this is no longer true.
Extension of the two-microphone transfer function method for impedance tube measurements
Authors: Chu W. T.
Published: October 2005

The two-microphone transfer function method for impedance tube measurements has been extended to include the effect of the tube attenuation.
Magnetically induced axial waves in a thermoelastic circular cylinder
Authors: Paul H. S. , Narasimhan R.
Published: October 2005

Magnetothermoelastic axial wave propagation for soft ferromagnetic materials is discussed, both analytically and numerically. Assuming that a constant magnetic field is applied along the axial direction, the frequency equation is obtained for linear thermal radiation and traction-free boundary conditions.
Child and adult vibrotactile thresholds for sinusoidal and pulsatile stimuli
Authors: Bernstein Lynne E. , Schechter Miriam B. , Goldstein Moise H.
Published: October 2005

Three experiments were performed to obtain vibrotactile sensitivity thresholds from hearing children and adults, and from deaf children. An adaptive two-interval forced-choice procedure was used to obtain estimates of the 70.7% point on the psychometric sensitivity curve. When hearing children of 5–6 and 9–10 years of age and adults were tested with sinusoids and haversine pulse stimuli, at 10, 100, 160, and 250 Hz or pps, respectively, only the 10-Hz stimulus resulted in an age effect. For this stimulus, young children were significantly less sensitive than adults. When sinusoids were again tested at 20, 40, 80, and 160 Hz, a small overall effect of age was observed with a significant effect only at 20 Hz. Two prelingually profoundly deaf children were tested with haversine pulse trains at 10, 50, 100, 160, and 250 pps. Both children were at least as sensitive to the tactile stimulation as were the hearing children and adults. Pulsatile stimulation, compared to sinusoidal stimulation, exhibited relatively flat threshold versus frequency functions. The present results, demonstrating no age effect for pulsatile stimulation and similar performance for deaf and hearing children, suggest that pulsatile stimulation would be appropriate in vibrotactile speech communication aids for the deaf.
Superresonant systems of scatterers. I
Authors: Tolstoy I.
Published: October 2005

Single compact scatterers insonified at frequencies near their intrinsic radial resonance ω0 act primarily as monopole sources, amplifying the local pressure field by a factor of order (kRa)−1, a being the scatterer radius and kR the wavenumber at ω0 in the surrounding material (kRa≂1.37×10−2 for air bubbles in water). This paper deals with systems of such scatterers (bubbles, inflated balloons, thin shells in water) which, through coupling via multiple scatter, may themselves exhibit true resonant modes at frequencies close to ω0, amplifying the local pressure field by a further factor of order (kRa)−1, leading to net amplifications in excess of 103 for bubbles or balloons, i.e., of over 120 dB for the intensity. This phenomenon, referred to as superresonance, is predicted by formulas for the equivalent source strength B of each scatterer of the system, proper account being taken of multiple scatter between all elements, using a self-consistent scheme. It has long been known that for a pair of scatterers (doublet), or in periodic lattices, B exhibits maxima for certain values of x=kl (l being the distance between scatterers), which had been called resonances [Twersky, J. Opt. Soc. Am. 52, 145–171 (1962)], but are in fact only partial (quasi) resonances. It is demonstrated here that, under suitable conditions, true resonances exist; i.e., in the absence of attenuation, B exhibits real poles (the infinities are removed by introduction of acoustic damping and finite radii). The existence of such superresonances is furthered by the presence of elastic boundaries in the fluid near the system (e.g., a thin plate or a solid half-space). Multiple scatter coupling then occurs by means of guided flexural or surface waves, which offer a more efficient energy transport mechanism between scatterers than the acoustic modes (volume waves) of a homogeneous fluid fullspace.

In the latter case, a doublet of resonant bubbles, or shells, exhibits no superresonances (poles), only partial ones (quasiresonances); it takes at least three scatterers to create a true superresonant system in a fullspace, and even so there is only one resonant spacing (kl=1.8955, ω=1.0022 ω0 for an equilateral triangle of bubbles in water). But near a thin plate, both doublet and triplet configurations develop spectra of resonant spacings xn and frequencies ωn. Near an elastic solid half-space, Stoneley (Scholte) wave coupling creates similar effects. The role of small interface roughness on this phenomenon is also examined.
Comodulation masking release: Effects of varying the level, duration, and time delay of the cue band
Authors: McFadden Dennis
Published: October 2005

The phenomenon of comodulation masking release (CMR) was studied in a series of experiments. When the relative level of the correlated cue band was more than about 10 dB less than that of the masker band, the CMR was abolished. When the duration of the tonal signal was varied with continuous maskers and cues, the course of the standard temporal-integration function (about −10 dB/decade) was followed by both the correlated-cue and the uncorrelated-cue conditions. In a burst masker paradigm employing several burst durations, the data for the correlated-cue condition closely followed the previously determined temporal-integration function. Finally, when the cue band was time delayed more than about 1.6 ms, the CMR began to decline, and it was abolished somewhere between 3 and 15 ms of delay, depending upon the subject. This latter outcome was essentially the same for masker and cue bands of both 75 and 100 Hz in width; in neither instance was there evidence of a cyclic, autocorrelation-like pattern following the period of the envelope. Supplementary experiments revealed two facts: The detectability of a masked narrow-band signal is not improved by the simultaneous presence of a correlated (or uncorrelated) noise band, and a small CMR can be obtained under conditions of forward masking.
Interaural correlations in normal and traumatized cochleas: Length and sensory cell loss
Authors: Bohne Barbara A. , Bozzay Denyse G. , Harding Gary W.
Published: October 2005

Sizable intraspecies variations have been found in both the length of the organ of Corti (OC) and the amount of damage resulting from exposure to a particular ototraumatic agent. These variations have made it difficult to address certain research questions such as the susceptibility of the previously injured ear to further damage. If intra-animal correlation is high, the variability problem could be circumvented by using the two ears from a given animal for different aspects of the same study. Therefore, correlation coefficients were calculated for OC length and for percentage of missing inner (IHCs) and outer hair cells (OHCs) in a large sample of chinchillas which included controls and animals which had been exposed to noise or treated with ionizing radiation. The correlation coefficients were +0.96 for OC length, +0.93 for IHC loss, and +0.97 for OHC loss.
Output statistics of the sample matrix inverse beamformer implemented in beam space
Authors: Gray D. A.
Published: October 2005

The probability density function of adaptive beam space estimates of the frequency-wave vector power is derived. The estimates are derived, at each frequency of interest, from the inverse of the cross-spectral matrix of the outputs of a conventional beamformer. From the probability density function, the detection performance of the beam space algorithm can be compared with the corresponding element space one. For very short integration times the beam space algorithm can, in certain noise fields, have a lower detection threshold than the element space one. An example, using experimental sonar data, is given to illustrate this.
Acoustic levitation methods for density measurements
Authors: Trinh E. H. , Hsu C. J.
Published: October 2005

The capability of ultrasonic levitators operating in air to perform density measurements has been demonstrated. The remote determination of the density of ordinary liquids as well as low density solid metals can be carried out using levitated samples with size on the order of a few millimeters and at a frequency of 20 kHz. Two basic methods may be used. The first one is derived from a previously known technique developed for acoustic levitation in liquid media, and is based on the static equilibrium position of levitated samples in the earth’s gravitational field. The second approach relies on the dynamic interaction between a levitated sample and the acoustic field. The first technique appears more accurate (1% uncertainty), but the latter method is directly applicable to a near gravity-free environment such as that found in space.
Resonance acoustic scattering from stacks of bonded elastic plates
Authors: Jackins P. D. , Gaunaurd G. C.
Published: October 2005

We have formulated the resonance scattering theory (RST) for the general case of acoustic reflection from (and transmission through) a stack of arbitrarily many elastic flat plates. The multilayered system separates two, possibly dissimilar, outer fluids. An incident plane harmonic wave impinges on the structure at an arbitrary angle of incidence from one of the outer fluids, and is subsequently reflected and transmitted. The simple form of the RST formulation permits a clear interpretation of the scattering process taking place in the structure. According to the RST, these resonances and the scattered waves they cause are described by a series of simple poles which yield meromorphic expressions for the transmission and reflection coefficients. The reflection coefficient is numerically computed and graphically displayed for several n-layered configurations, n≤4. In these figures the generally good agreement of the RST with the classical approach of Thomson [J. Appl. Phys. 21, 89 (1950)] and Haskell [Bull. Seismol. Soc. Am. 43, 17 (1953)] is demonstrated. We show how the multilayered formulation can be put in the same simple resonance form we have previously developed for single and double layered configurations, and we recover many of our earlier results for these simpler layered configurations. The methodology lends itself to the solution of some aspects of the inverse scattering problem for the entire structure.
Corrections to L. Schwarz, ‘‘On the theory of diffraction of a plane soundwave around a sphere’’ [‘‘Zur Theorie der Beugung einer ebenen Schallwelle an der Kugel,’’ Akust. Z. 8, 91–117 (1943)]
Authors: Cooper Duane H. , Bauck Jerald L.
Published: October 2005

Errors in the tables of L. Schwarz for Rayleigh diffraction, as noted by A. P. G. Peterson [J. Acoust. Soc. Am. 78, 266–267 (1985)], are surveyed in detail, and corrected and expanded versions of principal tables are offered herewith. The expansion arises from tabulation to a finer interval to represent the ripple overlooked by Schwarz.
Scattering from two and three gratings of densely packed compliant tubes
Authors: Radlinski Ronald P. , Janus Robert S.
Published: October 2005

Transmission of a normally incident plane wave through two and three different gratings of densely packed and highly eccentric compliant tubes in water is investigated. Structural beam modes are found to adequately describe the four categories of vibrational responses of the tubes. Insertion loss over a given bandwidth is studied by selectively changing the sequence of gratings and the separation among gratings. The restricted benefits from the use of three gratings are discussed in terms of the parameters which control the frequencies of transmission maxima. In all cases, the low-frequency performance can be understood in terms of equivalent circuits. At higher frequencies, newly introduced noncompliant modes can strongly reduce the compliance of tightly grouped gratings. Calculations are compared with experimental measurements for several configurations.
Extension of the Helmholtz integral equation method to shorter wavelengths
Authors: Tobocman W.
Published: October 2005

The Helmholtz integral equation method (HIEM) has been shown to be an efficient method for calculating the scattering of waves by arbitrarily shaped targets in the intermediate wavelength regime. The problems involved in treating the scattering of shorter wavelength waves by this method are investigated. The use of the Padé approximant method in place of matrix inversion by Gauss–Jordan elimination mitigates to a significant extent the need for large amounts of random access memory and computing time in shorter wavelength cases. Both the method of Schenck [J. Acoust. Soc. Am. 44, 41 (1968)] and the method of Burton and Miller [Proc. R. Soc. London Ser. A 323, 201 (1971)] are found to be effective in remedying the failure of the HIEM at the characteristic frequencies. However, it is found that when shorter wavelengths are used, the reduction in accuracy of the HIEM at characteristic frequencies tends to become less important. It was observed that at very short wavelengths low-order iteration of the HIE with the Kirchhoff approximation as zeroth iterate is probably the most practical method.
Declination has not been defeated—A reply to Lieberman e
t a
l.
Authors: ’t Hart Johan
Published: October 2005

In a recent paper, Lieberman et al. [J. Acoust. Soc. Am. 77, 649–657 (1985)] argue that, contrary to the view that the fundamental frequency in speech tends to fall slowly throughout an utterance (declination), such a lowering only occurs in the terminal part of the utterance (breath-group theory). This letter disputes the validity of their line of reasoning, which contains a number of incorrect deductions. A serious omission in their data presentation makes it impossible to test a highly plausible alternative interpretation of their results.
Alice in declinationland—A reply to Johan ’t Hart
Authors: Lieberman Philip
Published: October 2005

The paper that ’t Hart disputes [Lieberman et al., J. Acoust. Soc. Am. 77, 649–657 (1985)] refuted the general claim of declination theory, i.e., that the fundamental frequency always falls throughout an utterance. We are pleased to see that our paper has had the appropriate effect and that ’t Hart and other proponents of the declination theory have modified their stand and no longer hold to this extreme position. We did not claim that a lowering of fundamental frequency ‘‘only occurs in the terminal part of the utterance.’’ ’t Hart’s comments obscure the other points that we demonstrated in our paper. We showed that hand-drawn declination lines placed on F0 contours have different slopes when different observers draw them. To paraphrase a relevant line from Alice in Wonderland, hand-drawn declination lines can show anything you want them to show. The auditory matching procedure that ’t Hart uses in his own studies introduces additional possible errors that make his analyses almost meaningless.
Target detection by the beluga using a surface-reflected path
Authors: Penner Ralph H. , Turl Charles W. , Au Whitlow W.
Published: October 2005

During an echolocation-in-noise experiment we suspected that a beluga whale (Delphinapterus leucas) was using a surface-reflected path to maximize detection performance. We tested and confirmed this suspicion by acoustically and mechanically denying access to surface path information. The whale’s performance varied as the surface-reflected path was denied.
Speech amplitude statistics and the gamma density function as a theoretical approximation
Authors: Niederjohn Russell J. , Haworth Daniel G.
Published: October 2005

Knowledge of the speech amplitude density provides basic data concerning the statistics of the continuous speech waveform. The objective of this paper is to present data which characterize the longtime speech amplitude density utilizing a data base of sufficient size to describe the distribution. The data base consists of approximately 45 min of recorded speech for each of the 25 speakers. Two parameters of a theoretical gamma density function are estimated from the experimental data to provide the best curve fit between the experimental data and the gamma density function. Overall results presented in this paper substantiate three main conclusions: (a) There is a significant difference between the speech amplitude density for male and female speakers; (b) the speech amplitude density for positive speech amplitudes differs from that for negative speech amplitudes; and (c) the gamma probability density function is a better approximation for full-wave rectified speech than it is when considering just positive or just negative amplitudes.
Consonant recognition in quiet and in noise with aging among normal hearing listeners
Authors: Gelfand Stanley A. , Piper Neil , Silman Shlomo
Published: October 2005

Consonant recognition in quiet and in noise was investigated as a function of age for essentially normal hearing listeners 21–68 years old, using the nonsense syllable test (NST) [Resnick et al., J. Acoust. Soc. Am. Suppl. 1 58, S114 (1975)]. The subjects audited the materials in quiet and at S/N ratios of +10 and +5 dB at their most comfortable listening levels (MCLs). The MCLs approximated conversational speech levels and were not significantly different between the age groups. The effects of age group, S/N condition (quiet, S/N+10, S/N+5) and NST subsets, and the S/N condition ×  subset interaction were all significant. Interactions involving the age factor were nonsignificant. Confusion matrices were similar across age groups, including the directions of errors between the most frequently confused phonemes. Also, the older subjects experienced performance decrements on the same features that were least accurately recognized by the younger subjects. The findings suggest that essentially normal older persons listening in quiet and in noise experience decreased consonant recognition ability, but that the nature of their phoneme confusions is similar to that of younger individuals. Even though the older subjects met the same selection criteria as did younger ones, there was an expected shift upward in auditory thresholds with age within these limits. Sensitivity at 8000 Hz was correlated with NST scores in noise when controlling for age, but the correlation between performance in noise and age was nonsignificant when controlling for the 8000–Hz threshold. These associations seem to implicate the phenomena underlying the increased 8000-Hz thresholds in the speech recognition problems of the elderly, and appear to support the concept of peripheral auditory deterioration with aging even among those with essentially normal hearing.
Recognition of natural and time/intensity altered CVs by young and elderly subjects with normal hearing
Authors: Gordon-Salant Sandra
Published: October 2005

The purpose of this study was to evaluate the efficiency of three acoustic modifications derived from clear speech for improving consonant recognition by young and elderly normal-hearing subjects. Percent-correct nonsense syllable recognition was measured for four stimulus sets: (1) unmodified stimuli; (2) stimuli with consonant duration increased by 100%; (3) stimuli with consonant–vowel ratio increased by 10 dB; and (4) stimuli with both consonant duration and consonant–vowel ratio increased. Analyses of overall nonsense syllable recognition, consonant feature recognition, and consonant confusion patterns demonstrated that the consonant–vowel ratio increase modification produced better performance than the other acoustic modifications by both subject groups. However, elderly subjects exhibited poorer performance than young subjects in most conditions. These results and their implications are discussed.
Temporal effects in masking and their influence on psychophysical tuning curves
Authors: Bacon Sid P. , Moore Brian C. J.
Published: October 2005

Psychophysical tuning curves (PTCs) were obtained in simultaneous and forward masking for a 20-ms, 1000-Hz signal presented at 10 dB SL. The signal was presented at the beginning of, at the temporal center of, at the end of, or immediately following a 400-ms masker. The first experiment was done in quiet; the second experiment was done in the presence of two bands of noise on either side of 1000 Hz. The results were similar in quiet and in noise. In simultaneous masking, the PTCs were broadest for the signal at masker onset, and generally sharpest for the signal at temporal center; the differences were largest on the high-frequency side. In most cases, there was virtually no difference in Q10 between the forward-masking PTC and the simultaneous-masking PTC with the signal temporally centered, although the high-frequency slope was always steeper in forward masking. These results indicate that, at least for brief signals, frequency selectivity measured with simultaneous-masking PTCs and the degree of sharpening revealed in forward-masking PTCs depend upon the temporal position of the signal within the simultaneous masker.
A reply to Jacques Mehler’s ‘‘Review of The Biology and Evolution of Language’’ [J. Acoust. Soc. Am. 8
, 1558–1560 (1986)]
Authors: Lieberman Philip
Published: October 2005

Mehler takes an extreme Chomskian position and disputes the biological premises of my book. The Biology and Evolution of Language (Harvard U.P. Cambridge, MA). These premises are consistent with modern biological thought and data. Mehler distorts the tone, content, and intent of my book.
A proposal to honor the memory of Maurice A. Biot
Authors: Junger Miguel C.
Published: October 2005

It is proposed that the Acoustical Society of America honor the memory of Maurice A. Biot by attaching his name to the specialized form of Stoneley waves which occur at the interface of an incompressible liquid and an effectively massless elastic solid.
Reply to ‘‘Comments on ‘Sound generation by flow over relatively deep cylindrical cavities’ ’’ [J. Acoust. Soc. Am. 8
, 1530–1531 (1986)]
Authors: Parthasarathy S. P. , Kwack E. Y. , Back L. H.
Published: October 2005

This letter is a reply to comments made by S. A. Elder on a previous article by Parthasarathy et al. [J. Acoust. Soc. Am. 78, 1785–1795 (1985)].
A note on the Helmholtz equations for acoustic waves in inhomogeneous media
Authors: Ross G. , Chivers R. C.
Published: October 2005

The paper puts forward a vector Helmholtz equation for the particle velocity of an acoustic perturbation propagating in an inhomoeneous medium. The scalar (acoustic pressure) and vector (acoustic velocity) expressions for the scattered wave are derived and compared. Also, the importance of the source term in the Helmholtz equation is clarified.
On the time and geometry independence of elastodynamic spectral energy density
Authors: Weaver Richard L.
Published: October 2005

It is shown that the acoustic spectral energy density E(ω) deposited by an elastodynamic source is, at times, subsequent to cessation of action of the source, independent of time. It is furthermore shown that, suitably smoothed, E(ω) is independent of the distant geometry of the elastic body in which the source acts and thus that E(ω) may be calculated knowing only the source character and specimen geometry in the vicinity of the source. Inasmuch as the diffuse field assumption allows E(ω) to be estimated from simple measurements of the reverberant field, acoustic emission source character may be extractable from such measurements.
Normalized noise energy as an acoustic measure to evaluate pathologic voice
Authors: Kasuya Hideki , Ogawa Shigeki , Mashima Kazuhiko , Ebihara Satoshi
Published: October 2005

In order to evaluate noise components included in pathologic voice signals, a novel acoustic measure, normalized noise energy (NNE), is proposed and its effectiveness for the detection of laryngeal pathologies is investigated with 250 vowel samples spoken by 64 control (normal) subjects and 186 patients with various laryngeal diseases. The NNE is automatically computed from the voice signals using an adaptive comb filtering method performed in the frequency domain. Experiments with the voice samples show that the NNE is especially effective for detecting glottic cancer, recurrent nerve paralysis, and vocal cord nodules. Specifically, when glottic cancer is represented in terms of the T classification adopted by the UICC (Union Internationale Contre le Cancer), glottic T2–T4 cancer can be perfectly discriminated from normal samples, but 22.6% of patients with glottic T1 cancer are incorrectly classified as normal, with an error rate of 9.4% for normal subjects.
The perceived height of octave-related complexes
Authors: Deutsch Diana , Moore F. Richard , Dolson Mark
Published: October 2005

Subjects were presented with two-part patterns consisting of tones whose partials stood in octave, or near-octave relation. The perceived heights of the tones in the patterns were found to vary depending on their positions along the chroma circle, so that the patterns were perceived quite differently depending on which of two keys they were in. Implications of these findings are discussed.
A two-stage nonlinear cochlear model possesses automatic gain control
Authors: Geisler C. Daniel , Greenberg Steven
Published: October 2005

A model of the cochlea is explored using as stimuli two simultaneously presented sinusoids of equal amplitude. The model consists of two stages: a linear bandpass filter, followed by a reservoir-type representation of the hair-cell/nerve-fiber complex. Fast Fourier transforms of the model’s output were computed. While the amplitudes of the individual response components were strongly nonlinear functions of intensity, the ratio of the magnitudes of the response components at the frequencies of the two stimulating sinusoids was found to be nearly equal, over a wide intensity range, to the ratio of the amplitudes which those stimulating sinusoids possessed at the output of the filter. Thus the reservoir stage exerts ‘‘automatic gain control.’’
Spectral analysis of wall-pressure fluctuations in turbulent two-phase flow
Authors: Sami S. M. , Lakis A. A.
Published: October 2005

A closed two-phase flow loop system was designed and constructed to measure the spectral characteristics of wall pressure such as rms values, power spectral density, and axial-lateral cross correlations. In this loop, the two-phase flow entered a straight run of smooth plastic pipeline (PVC) having an inside diameter of 20.32 cm (8 in.), achieving at the test section a maximum Reynolds number in the order of 2×106 on a liquid basis. Measurements of the wall-pressure fluctuations in a turbulent dispersed two-phase flow were conducted using miniature semiconductor pressure transducers mounted flush with the internal surface of the rigid thick-walled metal pipe working test section. Narrow-band spatial correlations were obtained over different center band frequencies ranging from 56.22–891.24 Hz and flow velocities at liquid Reynold’s number of 0.819×106 to 2.0878×106. Lower values of the mixture velocity and the intensity of the pressure fluctuations were observed for high void fraction flows. In general, two-phase flow wall-pressure fluctuations were characterized by low-amplitude frequency spectra. Axial and lateral two-phase flow correlations have shown dependence upon the flow quality (volumetric mixing ratio) and Strouhal number. Two-phase flow wall-pressure field convection showed an increase at higher two-phase flow mixing ratio. The lateral microscale of turbulence was found to be approximately five times that of the axial direction.
Measurements of the nonlinear tuning curves of Helmholtz resonators
Authors: Wu Junru , Rudnick Isadore
Published: October 2005

The tuning curves of three Helmholtz resonators have been measured for sound-pressure level at the necks, from 28.1 dyn/cm2 to 1.59 × 104 dyn/cm2. It is found that, for thin-necked resonators, as the sound level is increased the peak frequencies shift to higher values by as much as 20%, and their impedances are in satisfactory agreement with earlier published results. It is found that, for long-necked resonators, the peak frequencies are relatively independent of the amplitude of acoustic pressure.
Sound penetration through an arbitrarily shaped aperture in a rigid screen: Analytical determination of the quadratic terms in low-frequency expansion
Authors: Fabrikant V. I.
Published: October 2005

Van Bladel has reduced the problem of low-frequency scattering through an aperture in a rigid screen to a sequence of static integral equations. Analytical solutions are known at the moment for a circular and an elliptic aperture only. A new analytical method is proposed here which is valid for the nonelliptical apertures. The method is based on an integral representation for the reciprocal distance between two points obtained earlier by the author. Specific approximate formulae are derived for evaluating the average value of the quadratic term in the low-frequency expansion for an aperture in the shape of a polygon, a rectangle, a rhombus, and a cross. All the formulae are checked against the solutions known in the literature, and a good accuracy is confirmed in a sufficiently wide range of the aspect ratio.
Inversion of data for near-grazing propagation over rough surfaces
Authors: Lucas R. J. , Twersky V.
Published: October 2005

Results for the coherent response to a point source irradiating an embossed plane [J. Acoust. Soc. Am. 76, 1847 (1984)] are applied to interpret and invert data obtained by Medwin et al. [J. Acoust. Soc. Am. 76, 1774 (1984)]. As emphasized earlier [J. Acoust. Soc. Am. Suppl. 1 74, S122 (1983)], key features arise from interference of elementary components of the corresponding Sommerfeld-type wave system based on the complex error function complement Q. Simplified analytical approximations are presented to emphasize the essential physics, and to facilitate initial estimates of unknown parameters. Refined estimates using Q integral theory are incorporated in graphical results to display primary data trends of the magnitudes and phases as well as the dependence of the incremental dispersion on both range and frequency.
On the coexistence of particle and turbulence scattering
Authors: Yang C. C.
Published: October 2005

A theory is presented to take care of a mixed system in which scattering effects from small particles and turbulences coexist. In this theory, a correlation function for irregularities is successfully derived such that it covers the variations due to sharp boundaries between particles and the surrounding medium, particle distributions, and volume concentration fluctuations. Hence, the theory of turbulence scattering becomes applicable to this mixed system when the Rayleigh approximation is valid. Numerical results are compared with experimental data from other research groups. Also, the coupling effect of, and the dominance between, these two kinds of scattering are discussed.
On plane-wave propagation in a uniform pipe in the presence of a mean flow and a temperature gradient
Authors: Munjal M. L. , Prasad M. G.
Published: October 2005

A theoretical study on the propagation of plane waves in the presence of a hot mean flow in a uniform pipe is presented. The temperature variation in the pipe is taken to be a linear temperature gradient along the axis. The theoretical studies include the formulation of a wave equation based on continuity, momentum, and state equation, and derivation of a general four-pole matrix, which is shown to yield the well-known transfer matrices for several other simpler cases.
Normal modes in a rough waveguide: Theory and experiment
Authors: Medwin Herman , Reitzel Ken J. , D’Spain Gerald L.
Published: October 2005

A rigid-walled waveguide has been studied theoretically and experimentally to determine how randomly rough, steep-sloped roughness elements change the eigenfunctions and eigenfrequencies of the waveguide. The grazing mode is found to travel subsonically with higher acoustic pressure at the rough wall than at the opposite smooth wall. Other modes have phase velocities that are greater than, or less than, those of the smooth-walled waveguide depending on closeness to their cutoff frequencies. The scattering parameters of a randomly rough natural surface are determined empirically and compared with data from studies of the coherent boundary wave propagating over a rough half-plane.
Ultrasonic absorption of bovine serum albumin solutions in the frequency range 60 to 160 kHz
Authors: Barnes C. , Evans J. A. , Lewis T. J.
Published: October 2005

The ultrasonic absorption of the globular protein bovine serum albumin in aqueous solution has been measured in the frequency range 60 to 160 kHz using a 2-l spherical resonator. The effect of pH change and of the denaturants urea, guanidine hydrochloride, and sodium dodecyl sulfate on the absorption loss has been studied. It is concluded that a significant ultrasonic absorption process exists which is related to structural helix-coil transition equilibria. For native protein the maximum loss appears to occur at a frequency at least as low as 70 kHz for a pH of about 4.2. This loss process is distinct from those arising from proton-transfer equilibria perturbations which are manifest at pH 3.2 and 11.6 and at peak frequencies of 400 kHz and above.
Optimal reconstruction algorithm for holographic imaging of finite-size objects
Authors: Lee Hua
Published: October 2005

This paper introduces the formulation of the optimal image reconstruction algorithm for finite-size objects. For practical data acquisition and computation considerations, the partial discrete (continuous–discrete) model is used for the formulation. The basic constraints utilized in this optimization process are the finite size of the object and the limited spatial-frequency bandwidth of the resultant wave field. The result indicates that the algorithm consists of a linear matrix transformation followed by backward propagation. It is also shown that the bandlimited wave field extrapolation method and backward propagation technique are degenerate cases of this optimal algorithm. In addition to image reconstruction, the formulation of this optimal algorithm can be used to determine the optimal wave field sampling for efficient data acquisition.
Characteristic impedance of humid air
Authors: Wong George S. K.
Published: October 2005

This paper describes the effects of humidity and temperature on the characteristic impedance ρc of standard atmospheric air. The characteristic impedance decreases with humidity and temperature. An approximate equation is given for the computation of ρc over the range of relative humidity from 0–1.0, and temperature from 0°–30 °C. The maximum uncertainty is estimated to be about 330 ppm.
Scattering by a slender body
Authors: Ahluwalia Daljit S. , Keller Joseph B.
Published: October 2005

Scattering of a time harmonic scalar field by a hard, soft, or transparent slender body is calculated. The wavelength is assumed to be long compared to the radius of the body cross section, but of any size compared to the body length. The scattered field is represented as an integral of fields from monopoles and dipoles distributed along the centerline of the body. The strengths of these are sources are determined by solving integral equations. Then the field is evaluated for bodies either long or short compared to the wavelength. For long bodies, the results of the geometrical theory of diffraction are obtained and the end diffraction coefficients are determined. For and the end diffraction coefficients are determined. For short bodies, the low-frequency results are found.
Texture of polycrystalline metals characterized by ultrasonic velocity measurements
Authors: Hirao M. , Aoki K. , Fukuoka H.
Published: October 2005

An ultrasonic method is presented for the nondestructive evaluation of the rolling texture in polycrystalline aggregate of cubic metals. Use is made of the elastic anisotropy measured by the propagation velocities of Rayleigh surface waves and surface skimming SH waves in the rolling plane. These velocity anisotropies permit the evaluation of the lowest three coefficients in the series expansion of the orientation distribution function and then enable the calculation of ‘‘ultrasonic pole figures’’ for the surface texture. The correspondence with the conventional x-ray pole figures is comparatively good for the aluminum alloy tested, showing that the ultrasonic pole figures properly approximate the conventional x-ray pole figures. The limitation and application are discussed.
Rayleigh wave speeds in transversely isotropic materials
Authors: Mase G. Thomas
Published: October 2005

Equations from which the Rayleigh (surface) wave speed can be determined are given for propagation on a transversely isotropic, linear elastic half-space. These equations are obtained from the vanishing of the determinant of a real symmetric second-order tensor which arises from the six-dimensional formalism of Barnett and Lothe [Modern Problems in Elastic Wave Propagation, edited by J. Miklowitz and J. D. Achenbach (Wiley, New York, 1978)]. To evaluate the components of this tensor, 18 integrals are evaluated explicitly. The resulting equations are discussed for a transversely isotropic aluminum aggregate with an idealized 〈111〉 texture.
Determination of structural modes via the Prony model: System order and noise induced poles
Authors: Braun S. , Ram Y. M.
Published: October 2005

The parameters of multiple degree of freedom structural systems can be identified from their impulse response via the Prony method. Overdetermining the system’s order is shown to improve the identification accuracy in noisy situations, but introduces additional mathematical poles. Described are methods to determine the necessary overdetermination and the true system poles. A novel, efficient perturbation method, based on the singular value decomposition, is shown to be effective under noisy situations.
Pulse–echo imaging via zero manipulation
Authors: Seggie D. A. , Doherty G. M. , Leeman S.
Published: October 2005

The use of frequency demodulation in ultrasound pulse–echo imaging is assessed. It is shown that the straightforward display of instantaneous frequency information results in an image that appears to bear little relationship to object structure. However, a modified frequency demodulation technique which overcomes this difficulty, and also offers a degree of on-line image processing power, is proposed. The method allows both the envelope and phase of the signal to be accessed by frequency demodulation processing, and is applicable to a wider class of data, such as seismic and speech signals.