bluuebunny/crossref_metadata_2025 huggingface dataset:
The relation between head size and auditory brain-stem response interpeak latency maturation
Authors: Ponton Curtis W. , Eggermont Jos J. , Coupland Stuart G. , Winkelaar Richard
Published: October 2005

In developmental populations, durations of auditory brain-stem response (ABR) I–III, III–V, and I–V vary substantially across individuals, particularly among preterm infants. Adult ABR interpeak latency has a strong correlation with brain-stem size and weaker correlation with head size. To determine if head size might contribute to this increased interpeak latency variability among infants, ABR data were normalized based on head circumference. Normalization by head circumference did not reduce interpeak variability. Further analyses revealed a negative correlation between interpeak latency and head circumference that varied as a function of age. Before 42 weeks conceptional age (CA), a significant relation exists between increased head circumference and decreased duration of the III–V and I–V intervals, but not the I–III interval. For infants older than 42 weeks CA, there was a significant relation between increased head circumference and decreased duration for the I–III intervals but not the III–V and I–V intervals. An age-dependent correlation between decreasing interpeak latency and increasing head circumference suggests that improved neural transmission through the auditory nerve and brain-stem pathway offset or even overcompensate for developmental lengthening of the sensory pathway. Also, developmental time constants obtained from nonlinear curve fit analyses were shorter for normalized than non-normalized data, particularly for the I–V interval. Therefore, correction of ABR data for the length of the sensory pathway may be important to estimate accurately maturation rate for developmental populations.
Radiation modes and the active control of sound power
Authors: Elliott S. J. , Johnson M. E.
Published: October 2005

Two formulations for calculating the total acoustic power radiated by a structure are compared; in terms of the amplitudes of the structural modes and in terms of the velocities of an array of elemental radiators on the surface of the structure. In both cases, the sound radiation due to the vibration of one structural mode or element is dependent on the vibration of other structural modes or elements. Either of these formulations can be used to describe the sound power radiation in terms of a set of velocity distributions on the structure whose sound power radiation is independent of the amplitudes of the other velocity distributions. These velocity distributions are termed ‘‘radiation modes.’’ Examples of the shapes and radiation efficiencies of these radiation modes are discussed in the cases of a baffled beam and a baffled panel. The implications of this formulation for the active control of sound radiation from structures are discussed. In particular, the radiation mode formulation can be used to provide an estimate of the number of independent parameters of the structural response which need to be measured and controlled to give a required attenuation of the radiated sound power.
A comparison of volume scattering strength data with model calculations based on quasisynoptically collected fishery data
Authors: Love Richard H.
Published: October 2005

Volume reverberation measurements were made between 800 and 5000 Hz in the Norwegian Sea in August 1988 and west of Great Britain in April 1989. Coincidentally, extensive fishery surveys were conducted at about the same time near the two experimental areas. A comparison of acoustic results with model calculations based on the fishery data provided the means to determine if volume reverberation can be reliably predicted from high-quality biological information. Good correlation between acoustic data and model results was obtained after several plausible modifications were made to the fishery information. Results indicate that blue whiting are the major scatterers off Great Britain and that both blue whiting and redfish are important scatterers in the Norwegian Sea. Before this study, blue whiting were expected to dominate in both areas and redfish had been assumed to be unimportant. The study shows that volume scattering strengths can be accurately predicted if the characteristics of the scatterers are well known.
Specular reflections of transient pressures from finite width plane facets
Authors: Clay C. S. , Chu Dezhang , Li Saimu
Published: October 2005

The reflections of transient pressure signals from hard (perfectly reflecting) finite width plane facets have been studied theoretically and experimentally. The experiments and theory used point sources, and sound pressures were observed in the specular direction. Theoretical solutions used the Helmholtz–Kirchhoff integral and incident spherical waves in the Fresnel approximation. The results of these laboratory experiments are compared to numerical evaluations of the integrals. Applications to acoustical oceanography and to architectural acoustics are: the specular reflection of waves from a reflecting facet on the seafloor and the specular reflection of sound waves from sound deflectors above a performer on a stage.
Numerical and laboratory modeling of propagation over troughs and ridges
Authors: Ainslie Michael A. , Wang Lian Sheng , Harrison Christopher H. , Pace Nicholas G.
Published: October 2005

Numerical predictions and laboratory measurements of the underwater sound pressure field are presented for four different bathymetry profiles: a range-independent control case, two trough shapes, and a ridge. Differences between numerical and experimental transmission loss are shown to be consistent with small differences in assumed water depth and these differences are used to invert the measured data to extract the actual bathymetry, using a simple explicit method applicable to slowly varying but otherwise arbitrary bottom profiles. In retrospect, measurement of the position of interference fringes provides a means of inferring the water depth profile.
Quantitative relationship between tissue composition and scattering of ultrasound
Authors: Sehgal C. M.
Published: October 2005

This study establishes quantitative laws by which the magnitude of ultrasonic scatter is related to the gross chemical composition of tissues, viz., water, fat, and collagen. Tissues are modeled as immiscible mixtures, the constituents of which are uniformly dispersed over the volume. Each component of the mixture causes the ultrasonic velocity of the medium to fluctuate about the mean value. Such localized variations in the refractive index of a medium cause propagating sound waves to scatter. It is proposed that the contribution of each component to the total fluctuation is in proportion to its volume fraction. The analysis shows that the scatter of ultrasound exhibits a complex nonlinear dependence on the concentrations of the individual components. From the knowledge of sound speed of individual components, total velocity fluctuations are determined for binary and three-component models of the tissue. Comparison of these values, with those estimated from scatter measurements, show a close correlation between the two sets. Collagen, although present in relatively small amounts in soft tissues contributes a significant portion of the total scatter. However, both fat and collagen fractions must be taken into consideration to account for the major fraction of the observed scatter. In conclusion, there is a direct relationship between tissue composition and scatter from tissues. Such dependence must also be taken into consideration, in addition to the correlation function and correlation lengths to explain backscatter or loss in a transmitted signal due to scatter from tissues.
The use of the matrix pencil method for the spectrum analysis of musical signals
Authors: Laroche Jean
Published: October 2005

In the context of spectrum analysis, high-resolution estimation methods present interesting alternatives to classical Fourier transform. These methods are based on the assumption that the analyzed signal is composed of damped sinusoids, and yield estimates of their parameters: frequencies, damping factors, original amplitudes, and phases. This paper investigates the use of a specific high-resolution estimation method, the matrix-pencil method, for the spectrum analysis of musical signals. In spite of its computational cost, this technique is shown to achieve extremely good results in the case of highly damped signals, short data records, or close frequencies.
Stimulus materials for audio-visual studies of attention and speech perception by the hearing impaired
Authors: Rakerd Brad , Seitz Philip F.
Published: October 2005

Individuals with sensorineural hearing impairment have been shown to devote a larger than normal share of their attention to speech processing when listening in situations that afford access to audio speech cues only. Attentional commitments may prove to be more nearly normal if both audio and visual speech cues are available. To test this possibility, a studio-quality videotape has been developed for use in primary-task and dual-task studies of attention and speech perception. Markers on the tape make it possible to maintain coordination with a computer. The timing of speech events is specified to within a few milliseconds, potentiating subject reaction time measurements. There are three sets of stimulus materials: (i) 30 to 45s samples of connected discourse; (ii) triplets of phonetically balanced monosyllabic words, arranged in an ABX format for discrimination experiments; and (iii) randomized lists of words and phonetically matched nonwords for lexical decision experiments. Copies of the videotape, along with supporting software and other test materials, are available upon request. [Work supported by NIH-NIDCD.]
Speech recognition and frequency discrimination with the Ineraid and CIS cochlear prostheses
Authors: Dorman M. F.
Published: October 2005

Measures of frequency discrimination and speech understanding were made for cochlear implant patients using the Ineraid, analog signal processor and for patients using the continuous interleaved sampling (CIS) processor. For patients using the Ineraid, measures of frequency discrimination are significantly correlated with performance on tests of speech understanding. The correlation coefficients range from 0.60 to 0.82 depending on the frequency domain of the discrimination test and on the nature of the test of speech understanding. When Ineraid patients were fitted with a CIS processor, speech understanding improved significantly. An improvement in frequency discrimination may be the principal factor in the high word recognition scores achieved by patients using the CIS processor. [Research supported by NIDCD.]
A multidimensional scaling analysis of vowel discrimination in humans and monkeys
Authors: Sinnott Joan M. , Brown Charles H. , Kressley Regina A.
Published: October 2005

Five humans and three African Sykes’ monkeys (Cercopithecusalbogularis) discriminated among the ten English vowels using a repeating background procedure. Human subjects are four native American-English speakers and one non-native Hispanic speaker. Reaction times were input to a multidimensional scaling analysis (ALSCAL) in order to derive a measure of perceived similarity or dissimilarity among the vowels. For all subjects, including monkeys, the front vowels were the most distinguishable vowel group, while the central and back vowels were less clearly differentiated. The Hispanic speaker performed similarly to the native American English speakers, although Spanish does not differentiate among the spectrally similar vowels of English. One difference that emerged between humans and monkeys was that humans appeared more sensitive than monkeys to first formant changes in the front vowels. [Work supported by NIDCD.]
Comparison of a parabolic equation model with Gaussian beam tracing in range-independent and range-dependent environments
Authors: Ruppel Timothy H. , Field Robert L.
Published: October 2005

Transmission losses predicted by the parabolic equation model FEPE over a 20- to 150-Hz frequency band are compared with transmission losses predicted by Gaussian beam tracing in range-independent and downslope environments. Ocean impulse responses, computed with each model, are also compared with experimentally determined responses previously reported. [R. L. Field and J. H. Leclere, J. Acoust. Soc. Am. 93, 2599–2616 (1993)]. As in the earlier paper, environmental inputs to the model are derived from the Ocean Drilling Project (ODP) sites near the experiment location, and impulse response comparisons are made using correlation coefficients. [Work supported by the Office of Naval Research Program Element 0602435, with technical management provided by the Naval Research Laboratory.]
Dishabituation of visual attention by natural and synthetic infant-directed speech stimuli varying in spectral properties
Authors: Kaplan Peter S. , Goldstein Michael H. , Owren Michael J.
Published: October 2005

A habituation–dishabituation paradigm was used to study acoustic characteristics of adults’ infant-directed (ID) speech that elicit infant visual attention. Five groups of 4-month-olds received twelve 10-s presentations of a checkerboard pattern. On the ninth trial, one of five auditory stimuli was presented. Differences in looking duration were compared on the trials before and after the auditory stimulus. Attention increased significantly after presentations of a natural, intact ID speech segment and after a version composed of sine waves simulating its fundamental frequency (F0) and first five harmonics (H1–H5). However, no significant changes in attention occurred following sine waves simulating the F0 only, the F0-plus-H1, or the harmonics only. The harmonics-only stimulus elicited significantly less responding than did any other stimulus. The roles of frequency modulation and spectral properties are discussed.
Perceptual evaluation of infant articulatory transitions
Authors: Roussel Nancye C. , Daniloff Raymond G.
Published: October 2005

The distribution of phonemic cues contained within consonant–vowel (CV) nonreduplicated (NRB) syllables of infants ages 6 to 15 months was compared to the distribution observed in adult productions [S. Furui, J. Acoust. Soc. Am. 57, 1016–1025 (1986)] to examine the extent of coproductive overlap of infant consonant and vowel gestures. Truncated versions of infant CV syllables were presented to adult listeners for syllable identification. Perceptual critical points (truncation point at which syllable identification fell below 60% for the first time) were determined for both initial and final truncation conditions, and critical intervals were calculated. Results revealed significant differences in the temporal distribution and strength of phonemic cues within the infant NRB CV syllable. Fewer than 1/3 of the infant syllables demonstrated normal, adult-like identification functions under both initial and final truncation conditions, and infant critical intervals were on the average 21/2 times longer than those of adult Japanese speakers. Results did not reveal a clear developmental progression towards either more adult-like critical interval durations or identification functions in the NRB syllables studied.
Factorization of propagator matrices for efficient computation of wave-fields in horizontally layered fluid–solid media
Authors: Ivansson Sven
Published: October 2005

The wave field is decomposed into its frequency–wave-number components. Compound matrices for solid layers provide a convenient way of computing the boundary values at a fluid–solid interface [M. B. Porter and E. L. Reiss, J. Acoust. Soc. Am. 77, 1760–1767 (1985)], with loss-of-precision control. A certain vector is propagated through a sequence of multiplications with compound matrices, one for each layer. It is shown that computations of this kind can be performed more efficiently if each compound matrix is decomposed as a product of sparse matrices that are applied in sequence. Two kinds of compound-matrix factorizations are proposed. In connection with dispersion computations, our first factorization gives a method that is related to the ‘‘fast form’’ of Knopoff’s method [F. Schwab etal., Bull. Seismol. Soc. Am. 74, 1555–1578 (1984)]. This algorithm is slightly more efficient, however, and its range of applicability is wider. The second compound-matrix factorization gives a method that is significantly faster than the ‘‘fast form’’ of Knopoff’s method. Very few arithmetic operations are needed. It also provides a good basis for analyzing the numerical performance of compound-matrix propagation. Finally, it is shown how propagator-matrix factorization can be used to enhance the efficiency for multi-frequency computations and computation of full wave-fields, by wave-number integration or modal synthesis.
Comparison of dual surface and tri-surface approaches for acoustical holography measurements of radiated and scattered fields
Authors: Sartori Michael A. , Clark Joseph A.
Published: October 2005

Using near-field measurements of the pressure field of an immersed structure, an estimate of the structure’s radiated field and scattered field can be made. With the pressure and the pressure gradient measured at discrete locations in the near field, a discretized solution of the exterior Helmholtz integral is solved to obtain the far-field pressure. This approach has been shown to work for both acoustic radiation and acoustic scattering problems. Using two normal surfaces to approximate the pressure gradient, parametric simulations were performed to determine the scattered field predictability of the approach for an insonified rigid sphere. The results indicate that this dual surface approach better predicts the scattered field when the surfaces are very close, which implies that a good approximation of the gradient is needed. A different approximation of the pressure gradient uses three surfaces instead of two. Using a cylindrical shaped measurement surface, the radiated pressure field from a monopole and the scattered pressure field from a rigid sphere are simulated for the different cases of the approximated gradient, namely the dual surface approach and the tri-surface approach. The effects on the predictability of the radiated field and the scattered field are discussed. [Work supported by ONR.]
Searching for attractors in speech and nonspeech respiration
Authors: Porter Robert J. , Hogue David M.
Published: October 2005

Our recent study of breathing during speech revealed that a nonlinear equation, originally proposed as a description of respiration during quiet breathing, may also provide a description of respiratory behavior during speech. This equation interrelates variables such as lung volume, airway resistance, and the duration of the utterance, and captures commonalities in the basic organization of the respiratory system during what have been considered different tasks or modes of behavior (i.e., speech and nonspeech). Further explorations of these data suggest that the mechanism underlying the behavior may be viewed as an attractor, possibly chaotic. The presence of such an attractor in respiratory patterns is supported by the findings of other researchers and is consistent with the adaptive nature of the system during speech and nonspeech tasks [e.g., M. P. Sammon and E. N. Bruce, J. Appl. Physiol. 70(4), 1748–1762 (1991)]. Descriptions of the attractor and some of its characteristics will be presented.
Determination of turbulent velocity correlations by the nonlinear scattering of crossed ultrasonic beams
Authors: Korman Murray S. , Parker James E.
Published: October 2005

The nonlinear interaction of two, mutually perpendicular crossed ultrasonic beams, overlapping in the presence of turbulence, generates a scattered sum frequency component that radiates outside the interaction region. In the absence of turbulence, virtually no scattered sum frequency component exists (outside the interaction region). A theoretical investigation is reported that relates the shape of the ensembled averaged scattered sum frequency intensity spectrum, I+ (ω,θ*) (which exhibits a Doppler shift, frequency broadening, skewness, and kurtosis), to the scattering angle θ*, incident and scattered wave vectors (where K+=ks−[k1+k2]), and statistical properties of the turbulent velocity field v. The n spectral moments 〈(K+⋅v)n〉∝∫I+(ω,θ*) (ω−〈ω〉)n dω (obtained from experiment) are used to evaluate turbulent velocity correlations like 〈vxvy〉, where n=2. The scattering geometry involves rotating the axis of the transmitting crossed beams (which are always perpendicular to each other) in the plane containing the submerged circular water jet and receiver axes. Angle θ* is measured between the ray bisecting the transmitting axes and the stationary receiver axis. The crossed beams are focused and overlap at the common focal point. Spectral moments, obtained from scanning the overlap region across the jet, are used to predict velocity correlations across the width of the jet with good spatial resolution.
Comparison of measured and predicted pure tone propagation levels from JAPE-1: An evaluation of the performance of ASOPRAT
Authors: Frederickson Carl K. , Bass Henry E. , Raspet Richard , Messer John
Published: October 2005

Short-range propagation data (<2 km) from the Joint Acoustic Propagation Experiment Phase One (JAPE-1) has been used to evaluate the performance of the advanced sound propagation in the atmosphere (ASOPRAT) computer code. Speakers mounted 2 and 30 m above the ground were used as pure tone sources for the short-range measurements. Pressure levels measured in the time domain have been Fourier analyzed to produce plots of the pressure due to a particular frequency over time. Meteorological profiles measured at the experiment site were used as input for the prediction routine ASOPRAT. Agreement between the predicted and measured propagation losses is very good. Source strength data were not available as of the writing of this abstract, so at this time comparisons are all relative to a reference microphone at the ground. Source strength data may be available by the time of the meeting.
Measurements of finite amplitude pulses radiated by plane circular pistons in water
Authors: Averkiou Michalakis A. , Hamilton Mark F.
Published: October 2005

Measurements are reported for finite amplitude acoustic pulses radiated by plane circular pistons in water. Pulses with center frequencies of several megahertz, peak sound pressures up to 1 MPa, durations ranging from approximately 2 to 20 cycles, and different amplitude and frequency modulations were investigated. Measurements of short pulses were made very near the source, where the center wave and edge wave can be separated. Pulse envelope distortion that accompanies shock formation in frequency-modulated tone bursts is demonstrated. Acoustic saturation of pulsed sound beams is also investigated. All measurements are compared with theoretical predictions obtained from a computer code that solves the KZK equation in the time domain [Lee and Hamilton, UltrasonicsInternational 91 ConferenceProceedings (Butterworth–Heinemann, Oxford, 1991), pp. 177–180]. Very good agreement between theory and experiment is obtained both in the near field and the far field, on and off axis. Artifacts in measurements of waveforms containing shocks, which are attributed to bandwidth limitations of membrane hydrophones, are discussed. [Work supported by the Packard Foundation and the Office of Naval Research.]
Energy branching of a subsonic flexural wave on a plate at an air–water interface: Transition radiation and the acoustic wave field in water
Authors: Matula Thomas J. , Marston Philip L.
Published: October 2005

The diffraction of subsonic flexural plate waves due to a discontinuity in fluid-loading is experimentally investigated. A tone burst of flexural waves propagates down a plate, the lower section of which is submerged in water. Observations indicate that there occurs a branching of energy as the flexural wave passes through the air–water interface. A portion of the energy continues along the plate as a subsonic flexural wave with an associated evanescent wave. A second acoustic wave (which is termed transition radiation) originates at or near where the plate crosses the interface, and propagates in water to the far field. In the near field of the interface there exists an interference between the two acoustic waves in water that results in a series of pressure nulls. The pressure nulls are associated with a π phase change in the wave field and are indicators of wave front dislocations [P. L. Marston, ‘‘Geometrical and Catastrophe Optics Methods in Scattering,’’ PhysicalAcoustics (Academic, New York, 1992), Vol. 21, pp. 1–234]. A computation of the wave field in an unbounded fluid due to a line-moment excitation of a plate is comparable with the null pattern observed but differs in certain details. [Work supported by ONR.]
Computation of turbulent boundary layer wall pressure spectra
Authors: Capone Dean , Lauchle Gerald C.
Published: October 2005

The suitability of various wave-vector–frequency spectral models for predicting the point wall pressure spectrum due to developed turbulent boundary-layer flow over planar, rigid surfaces is investigated. The incompressible and compressible models developed previously [D. Chase, J. Sound Vib. 112, 125–147 (1987)] are given particular attention. The effect of finite-sized measurement transducers is included in the integration of the theoretical wave-vector–frequency spectrum over the in-plane wave numbers in order to arrive at an attenuated point pressure frequency spectrum that can be compared directly to existing experimental data [G. Schewe, J. Fluid Mech. 134, 311–328 (1983) (air), G. C. Lauchle and M. A. Daniels, Phys. Fluids 30, 3019–3024 (1987) (glycerine), and M. P. Horne and R. A. Handler, Exp. Fluids 12, 136–139 (1991) (water)]. The selected experiments cover a wide range of fluid properties and Reynolds numbers: it is found that the optimum set of empirical constants needed to exercise the Chase models depends on the experiment considered. The need to consider viscous effects in future modeling is borne out when dealing with viscous fluids like glycerine. [Work supported by various U.S. Navy projects at NSWC and ARL Penn State.]
Acoustic intensity measurements in the presence of low Mach number turbulent flow
Authors: McNeal Toby , Lauchle Gerald C.
Published: October 2005

Acoustic intensity measurements using the two-sensor cross-spectral density technique are susceptible to errors when made in the presence of mean flow. These errors are predominantly due to turbulent pressure fluctuations acting on and near the sensors. To quantify these errors, intensity measurements were performed in a sound field that contained both an independent acoustic source and a mean, low Mach number (M<0.1), turbulent boundary-layer flow. The microphones were flushed mounted in the wall supporting the turbulent boundary layer and the acoustic source was positioned a large distance downstream. The streamwise component of intensity was measured with and without the flow keeping the sound output of the source constant. Associated bias errors were calculated in accordance with a theoretically established bias error [G. C. Lauchle, Noise Control Eng. J. 23, 52–59 (1984)]. As predicted theoretically, the calculated bias error decreases rapidly as the sensor separation distance increases relative to the correlation length associated with the turbulent boundary-layer pressure fluctuations. [Work supported by various U.S. Navy projects at NSWC and ARL Penn State.]
Acoustic correlates of the fortis/lenis contrast in Swiss German plosives
Authors: Fulop Sean A.
Published: October 2005

Features of articulatory tension in plosives, such as increased closure duration, have not been shown to be perceptually salient in the time following the plosion (with the exception of increased F0) but are thought to influence perception by their appearance in the closure phase preceding plosion [K. Kohler, Phonetica 36, 332–343 (1979)]. Kohler [Phonetica 41, 150–174 (1984)] has claimed that the two plosive classes in Swiss German cannot contrast initially (where closure features are not audible), as neither voicing nor aspiration supports the contrast. This paper reports preliminary acoustic data (spectrograms) obtained from the natural production of Swiss German plosives by a native speaker. The data indicate that sonarants following fortis consonants exhibit increased high formant clarity and intensity in relation to the first spectral peak. Kohler and W. A. van Dommelen [J. Phon. 15, 365–381 (1987)] show a similar acoustic feature to be associated with global ‘‘tense voice’’ manner in the vowels surrounding intervocalic plosives. It is thus suggested that the observed acoustic feature is one of tension associated with the production of fortis plosives in Swiss German, and that this is available to maintain the fortis/lenis contrast initial position.
Spatial coherence measurement of sound in the northwest Pacific Ocean
Authors: Guan Dinghua , Zhu Ruichao , Zhang Renhe , Chen Yaoming
Published: October 2005

An experiment on the transverse horizontal spatial coherence of sound propagating in the ocean was performed jointly by Chinese and Russian acousticians in the northwest Pacific Ocean in June 1990. Three hydrophones with spacings of 270 and 130 m were put in the water at a 30-m depth. The acoustic source with four cw (from 109 to 860 Hz) and a broadband pseudorandom noise signal was drifted at a depth of 100 m. Part of the measurement results of up to 140 km are presented in this paper. It seems that the spatial coherence was related to the amplitude of the received signals and rises considerably in convergence zones.
Crosswind effects on acoustic propagation
Authors: Sprague Mark , Raspet Richard , Ostashev V. E.
Published: October 2005

Ray theory says that a ray moving in a crosswind will drift out of the plane of propagation, and that this effect can be significant with high windspeeds and over long propagation distances. White and Li [Michael J. White and Y. L. Li, J. Acoust. Soc. Am. 92, 2405 (A) (1992)] and Wilson [D. Keith Wilson, J. Acoust. Soc. Am. 92, 2405 (A) (1992)] developed two-dimensional fast-field programs (2DFFPs) to calculate the sound pressure levels of windy atmospheres. They reported that crosswind effects were negligible for the cases they considered and that a one-dimensional stationary phase solution yields accurate results. Ray analysis of the two-dimensional phase space used in the 2DFFP indicates that there is a small region that contributes significantly to the sound level. In the presence of a crosswind, the one-dimensional stationary phase approximation does not include all of this region. 2DFFP calculations for realistic windspeeds that show crosswind drift are presented, and the 2DFFP calculations are compared to the calculations of a one-dimensional stationary phase approximation.
Consonant context affects perceived similarity of North German and American English vowels
Authors: Strange Winifred , Trent Sonja A. , Stack Janet W. , Ling Xiange , Rodriguez Alba I.
Published: October 2005

Several current theories of L2 learning attempt to predict relative difficulties in learning to produce phonetic contrasts of a foreign language on the basis of the non-native phones’ phoneticsimilarity to native phoneme categories. In this study, monolingual speakers of American English (AE) were asked to categorize (into AE vowel categories) instances of the 14 North German (NG) vowels and to judge their goodness-of-fit on a seven-point scale. Multiple tokens of each vowel were produced in /C-vowel-t/ syllables (where C=/b,d,g/) in a carrier sentence. Results indicated that both the proportion of assignments to particular AE categories and the goodness-of-fit ratings were influenced significantly by the initial consonantal context. While front rounded NG vowels were categorized more often overall as back rounded AE vowels than as front unrounded AE vowels, front unrounded responses were significantly greater for front rounded vowels in labial context than in alveolar and velar contexts. In addition, the categorization of several NG vowels indicated significant individual differences among subjects in categorization patterns. Implications of these findings for conceptualizations of native-language phonetic ‘‘prototypes’’ as discussed.
Response and radiated pressure Green’s functions from a fluid-loaded cylindrical shell
Authors: Cuschieri J. M. , Feit D.
Published: October 2005

The solution for the response and radiated pressure from a fluid-loaded, infinite, cylindrical shell with a circumferential line load, is a classical problem in structural acoustics. Although this represents a rather fundamental problem, the solution for the Green’s function typically involve a contour integration for each spatial point of interest. An alternative approach has been developed which solves for the Green’s functions without the need to use a contour integral, for every spatial location, and without the need to introduce structural damping. The approach is a hybrid numerical/analytical solution, where the numerical part is based on an inverse discrete Fourier transform (IDFT) and the analytical part is the contribution of some of the poles in the solution which have to be removed to eliminate the singularities from the integrand of the IDFT. The singularities in the integrand are attributed to the real and near real poles of the fluid-loaded cylindrical shell response in the wave number domain. The location of the singularities is obtained using a numerical search algorithm and therefore the developed solution can be used to more complex geometries involving the fluid-loaded cylindrical shell. Results will be presented which match well with results found in the literature. [Work sponsored by ONR.]
Trade-off between burst cues and transition cues in the perception of prevocalic stop consonants: Predictions from acoustical measurements
Authors: Smits Roel , Collier René
Published: October 2005

Two male Dutch talkers produced two tokens of each of 20 stop-vowel syllables (/b,d,p,t,k/ followed by /a,i,y,u/). The release bursts were separated from the voiced parts and four types of stimuli were created: Burst-only stimuli (BO), burstless stimuli (BL), stimuli with cross-spliced bursts, where burst and transitions indicate conflicting place-of-articulation information (CS), and original utterances (OR). These stimuli were presented to 20 subjects for identification. Results show the well-known vowel-dependent trade-off between burst cues and transition cues. An attempt was made to predict the confusion matrices from acoustic properties of release bursts and formant transitions using Luce’s similarity-choice model. Most of the variance (89%) in the confusion matrix for the BO condition was explained using a spectral tilt measure and a spectral compactness measure. Much of the variance (80%) for the BL condition was explained using frequencies of F2 and F3 at voicing onset and of F2 in the vowel. Using the same burst and transition measures for the CS condition the explained variance dropped to 40%. Preliminary results show better predictions when acoustic measures are used which integrate over burst and transitions.
Perception of just-noticeable time displacement of a tone presented in a metrical sequence at different tempos
Authors: Friberg Anders , Sundberg Johan
Published: October 2005

The jnd for a perturbation of the timing of a tone appearing in a metrical sequence was examined in an experiment, where 30 listeners of varied musical background were asked to adjust the timing of the fourth tone in a sequence of six, such that they heard the sequence as perfectly regular. The tones were presented at a constant interonset time that was varied between 100 and 1000 ms. The average jnd was found to be about 10 ms for tones shorter than about 240-ms duration and about 5% of the duration for longer tones. Subjects’ musical training did not appear to affect these values.
Continuing development of the acoustics laboratory at the Cooper Union
Authors: Raichel Daniel R.
Published: October 2005

As a result of the addition of new equipment, the scope of the acoustics laboratory curriculum at the Cooper Union is being widened to include the use of FFT analyzers, reverberation meter, vibrating table, etc. Research projects are required of undergraduate seniors and graduate students must meet thesis requirements. The laboratory also serves as a research center for those interested in physical acoustics, environmental sciences, architectural acoustics, loudspeaker design, design of musical instruments, acoustics for medical diagnoses and treatment, and other acoustics-related topics. Newly established liaisons between the Cooper Union Research Foundation and other institutions (Riverside Research Institute, New York University Medical Center, U.S. Navy) open up additional opportunities for thesis work and provide access to even more equipment outside the laboratory. Even freshmen taking an integrated design course obtain acoustical laboratory experience by working in the anechoic and reverberation chambers in studying sound effects around an abstract sculpture being planned for installation in New Mexico. [Work supported by NSF and the New York State Science and Technology Foundation.]
Ultrasonic dispersion resulting from inelastic gaseous collisions and some inferences regarding molecular interactions and force laws
Authors: Amme Robert C.
Published: October 2005

Ultrasonics has been, and remains, a valuable technique for the investigation of vibrational energy transfer in polyatomic gases. The celebrated theory of Schwartz, Slawsky, and Herzfeld (SSH) has proven to be greatly successful in predicting the efficiency of V–T processes, particularly for self-collisions of diatomic species or between these species and the noble gases. For more complex molecules, particularly those containing hydrogen atoms, the role of vibrational amplitudes and of rotational (R–T and V–R,T) energy transfer effects may complicate the picture. Moreover, the presence of multiple relaxation processes may cause further departure from single relaxation steps in the sound velocity measurements. Nevertheless, the basic approach of SSH theory remains qualitatively correct in many cases, once the proper relaxation process and the interaction potential are identified. Vibrational collisions numbers Z10, in polyatomic molecules, i.e., the average number of collisions required for the vibrational transition v=1→v=0, will be discussed both for room temperature ultrasonic measurements and, for some species, over a range of temperatures. Various predictive schemes will be reviewed, and some recent results on substituted ethanes and their mixtures will be presented. It will be shown that the SSH formulation gives agreement with these experiments when a very steep repulsive potential is employed.
Blast injury in humpback whale ears: Evidence and implications
Authors: Ketten D. R. , Lien J. , Todd S.
Published: October 2005

To date, there is no published report of effects on marine mammal hearing from underwater explosions. External injuries consistent with inner ear damage have been found in dolphins subjected to Class C explosives, but often little change is seen in surface animal behavior near blast areas [Richardson etal., OCS MMS/90-0093 (1991)]. In this study, temporal bones from two humpback whales, which died following a 5000-kg explosion in Trinity Bay, Newfoundland [Lien etal., J. Acoust. Soc. Am. 94, 1849(A) (1993)], were harvested, preserved in formalin, scanned with 1-mm-high resolution spiral CT, decalcified, and sectioned at 20 μ. Evidence of mechanical trauma was found in all four ears: Round window rupture, ossicular chain disruption, sero-sanguinous effusion of peribullar spaces, and dissection of the middle ear mucosa with pooled sera. In one animal, there were bilateral periotic fractures. These observations are consistent with blast injury reports in humans, particularly with damage to victims near the source who sustained massive, precipitous increases in cerebrospinal fluid pressure. There was no evidence that the pathologies found in these whales resulted from repeated barotrauma or chronic infection, and no similar abnormalities were found in control ears from humpbacks not exposed to blasts. While the results show whales, like other mammals, are subject to severe blast trauma, it remains unclear whether lower level stimuli induce temporary and/or acute threshold shifts in marine mammals. [Work supported by ONR Grant. No. N00014-92-J-4000.]
Simultaneous measurement of structural vibration and temperature using an embedded optical fiber in a flat plate composite structure
Authors: Chiu Bornain , Hastings Mardi C.
Published: October 2005

Numerical results from this study show that a single polarization-maintaining optical fiber embedded in a composite flat plate is able to simultaneously measure low-frequency structural vibration and temperature. Theoretical estimates of sensitivities for the optical fiber sensor are presented with consideration of the cross sensitivity caused by simultaneous disturbances. An analysis of the composite plate and fiber based on the theories of linear elasticity and photoelasticity is used to estimate sensitivities of the embedded fiber. A finite element analysis using ANSYS is used to determine the state of stress in the composite plate. Results of this study show that simultaneous changes in structural vibration and temperature can easily be resolved.
Environmental source tracking using measured replica fields
Authors: Kuperman W. A. , Collins Michael D. , Perkins John S. , Fialkowski Laurie T. , Krout Timothy L. , Hall Lindsay , Marrett Ralph , Kelly Lesley J. , Larsson Ashley , Fawcett John A.
Published: October 2005

Preliminary results will be presented for TESPEX (Test of Environmental Signal Processing Experiment), which was performed in May 1993 off the east coast of New Zealand in a region of three-dimensional bathymetry variations. This complex environment was exploited to minimize ambiguity in environmental source tracking with a single receiver [Collins etal., J. Acoust. Soc. Am. 90, 2366 (1991)]. To overcome limited knowledge of environmental parameters, the acoustic field was measured by a fixed array of receivers while a ship towing a source swept over a sector. The receivers were linked to a recently developed satellite telemetry buoy that transmitted time series to a centralized computer facility for real time analysis. Expensive ship time was traded off for cheap computation time by interpolating the acoustic field using a WKB representation that permits a sparse sampling in azimuth. The main computational task for the data basing involves solving a nonlinear optimization problem for the WKB amplitude and phase functions, which vary slowly with range and azimuth. TESPEX data have been used to perform environmental source tracking using replicas constructed from the acoustic field data base. a)Present address: Scripps Institution of Oceanography, La Jolla, CA 92093.
Experiencing the aural environment of buildings
Authors: Siebein Gary W. , Gold Martin
Published: October 2005

A simple audio system was developed to allow architecture students to simulate the aural environment of various rooms. A basic set of exercises provide a conceptual and aural understanding of the room impulse response method for evaluating subjective acoustic qualities of rooms. The focus of the exercises is to provide a structure for the experiential understanding and manipulation of acoustics of buildings in applied design situations. Aural demonstrations illustrating how changes in the impulse response such as the loudness, direction, and number of early reflections as well as the subsequent reverberation affect the perceived acoustical qualities of speech and music are shown for various environments. The exercises are implemented using anechoic music recordings played via loudspeakers or headphones. The impulse responses are simulated using digital delay and reverberator units. Once they become familiar with the equipment, students can actually manipulate listening conditions easily for an endless opportunity of listening experiences.
Elastic constants and damping using ultrasonic resonance spectroscopy: Application to monocrystal and polycrystal copper
Authors: Ledbetter H. , Fortunko C. M. , Heyliger P.
Published: October 2005

Several authors used ultrasonic resonance spectroscopy to determine a material’s elastic-stiffness constants, the Voigt Cij. Complementary to these are the out-of-phase Cij*, which give the complete elastic stiffness C̃ij=Cij+iCij*. Here, Cij* measurements for both monocrystal and polycrystal copper are reported. For the monocrystal case, the Cij* vary strongly with the vibrational mode. And, when interpreted against a vibrating-string dislocation model, the Cij* present several surprises. For the polycrystal, the Cij* are much lower and nearly independent of vibration mode.
An experimental investigation of the phase difference between lip vibration and acoustic pressure in brass instrument mouthpieces
Authors: Yoshikawa S. , Plitnik G. R.
Published: October 2005

Over a century ago, Helmholtz classified reed instruments as those which tend to blow closed as the blowing pressure increases (the mechanical reed instruments), and those which tend to open as blowing pressure increases (the lip reed instruments). All subsequent work has tacitly assumed that these models are correct, and although measurements on clarinet-like systems support the inward-blowing model, the outward-blowing hypothesis has been widely used as the basis for theoretical models of the brass instrument’s sounding mechanism without experimental verification. As an alternate theory, the hypothesis that the vibrating lips of a brass player may act as an inward-blowing reed has been investigated. For this preliminary study, the phase difference between lip vibration and acoustic pressure was measured in several different lip-driven devices: a cylindrical tube without a mouthpiece, a French horn mouthpiece coupled to a nonresonant practice pipe, and a trumpet. By means of this experiment study, it is hoped that a definite resolution to the operating mechanism for the vibrating lips of brass players will be effected.
Acoustic studies of high-T
c oxide superconductors
Authors: Ledbetter H.
Published: October 2005

Various acoustic studies of high-Tc oxide superconductors, mainly cuprates, will be reviewed. Transition temperatures Tc range from about 20 K for the electron-conductor, (Pr-Ce)2 CuOΔ, to about 125 K for thallium cuprate. Properties considered include sound velocities, elastic constants, attenuation, Debye characteristic temperature ΘD, and Grüneisen parameter. Variables considered include composition, temperature, pressure, and magnetic field. Especially the polycrystals are complicated by defects such as twins, voids, microcracks, nonhomogeneities, texture, and impurity phases. Even monocrystals are seldom defect-free. Most studies focused on the YBa2Cu3Ox compound, where x varies between 6 and 7. The bismuth cuprates behave differently from most other compounds, perhaps because of incommensurate structural modulations. No convincing evidence exists that the new superconductors show velocity-temperature or attenuation-temperature curves similar to conventional BCS superconductors. This suggests a mechanism different from the simple s-electron spherical-fermi-surface weak-coupling BCS model. However, the new mechanism involves phonons. A relationship between Tc and ΘD has been established for four systems: La–O, Y–O, Bi–O, Tl–O. Interrelationships among acoustic properties and other physical properties such as thermal expansity and specific heat are emphasized. It is emphasized that some acoustic properties, especially the bulk modulus, can be estimated from simple models. Finally, topics are recommended for further study.