bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of envelope power on the ability to lateralize three-tone complexes on the basis of interaural envelope delays
Authors: Dye R. H. , Stellmack M. A. , Niemiec A. J.
Published: October 2005

In the present experiment, envelope power was varied by setting the starting phases of the three components of a complex 0°−0°−0° (high), 0°−45°−0° (medium), or 0°−90°−0° (low). Threshold interaural envelope delays were measured in a 2-AFC task as a function of frequency spacing (Δf = 25, 50, 100, and 200 Hz) with the carrier frequency (fc) set to 4000 Hz. The level of each component was 50 dB SPL, and the signal duration was 200 ms with 10-ms linear rise/decay times. For comparison, thresholds were also measured for SAM 4000-Hz tones with reduced depths of modulation so that the effects of decreasing modulation depth and decreasing envelope power could be directly compared. Reducing envelope power had only a negligible effect on threshold interaural envelope delays for Δf's of 200 and 100 Hz but a large and systematic effect at 50 Hz and especially at 25 Hz. For three of the five observers, the 0°−90°−0° Δf = 25-Hz condition was so difficult that 75% correct could not be reached with delays as large as 2000 μs. While reductions in the depth of modulation also elevated thresholds, the agreement was not particularly good between the data obtained with SAM tones and equal-amplitude components of the same Δf and comparable envelope power. In general, the results obtained here are consistent with binaural cross correlation of the outputs of envelope detectors.
Buildup and breakdown of the precedence effect
Authors: Freyman Richard L. , Clifton Rachel K. , Litovsky Ruth Y. , Balakrishnan Uma
Published: October 2005

Dynamic variations in the strength of echo suppression were investigated through earphone simulation of the free-field precedence effect. Each test stimulus consisted of two click pairs, with the interaural time parameters of the leading and lagging pairs reflecting stimuli originating from opposite sides of the head. Echo thresholds, the minimum lagging click delay required for subjects to report hearing an echo click, were obtained in two basic conditions: (a) test click presented in isolation, and (b) test click preceded by a train of clicks identical to the test click. The most striking finding was that the presence of the preceding click train usually elevated the echo threshold of the test stimulus relative to its threshold when presented in isolation, suggesting that echo suppression builds up during the click train. The magnitude of the effect was influenced by the number of clicks in the train and the period of silence between the end of the train and the test click. The effect is surprisingly persistent, lasting through several seconds of silence. Partial release from the built-up suppression occurred when the lead and lag locations of the test click were reversed from the clicks in the preceding train. [Work supported by NSF.]
Tongue positioning and dynamics during production of tense and lax vowels in CVC contexts
Authors: Dagenais P. A.
Published: October 2005

A comparison between tense and lax vowel pairs was undertaken using simultaneous recordings of tongue movements via glossometry and audio signals. A normal speaker recorded five repetitions each of three pairs of tense-lax vowels (i-ı, æ-ɛ, u-o) in pipsire context (əpvp, ətvt, əkvk). Measures for maximum tongue displacement, durations and velocities of physiological onglide, and target and offglide movements relative to the acoustic release of the initial plosive were taken. Greater maximal displacement from a central position was noted for all tense vowels. In pvp contexts, consistent preplosive anticipatory positioning was found for all vowels, and maximal tongue positioning for the lax vowels was achieved 50 ms prior to the tense vowels. For both lingual plosive contexts, tense vowel movements had longer total durations but slower onglide and offglide velocities than their lax counterparts. These results will be discussed in terms of biomechanical restrictions for production and the effects of perceptual saliancy and coarticulation. [Work supported by NIH Grant NS24697.]
Relationship between vowel height and speaking rate in American English
Authors: Gopal H. S. , Manzella Joyce , Stuman Lillian
Published: October 2005

The phonetic dimension of vowel height seems to be represented reliably and robustly by the difference beween Bark-transformed F1 and F0 [A. K. Syrdal and H. S. Gopal, J. Acoust. Soc. Am. 79, 1086–1100 (1986)]. This study examined the relationship between speaking rate and two acoustic-auditory correlates of vowel height. Measurements were made of F0, F1, vowel duration, and sentence durations of /pVC/ target syllables containing one of four pairs of high-low vowels and voiced or voiceless stops or fricatives. Target syllables were produced in sentence context at three different speaking rates by two male and two female native American English speakers. Results will be reported and discussed for two correlates of vowel height: changes in F1 and changes in the difference between Bark-transformed F1 and F0 as a function of speaking rate.
Minimalist synthesis of /bVb/ stimuli
Authors: Andruski Jean E. , Nearey Terrance M.
Published: October 2005

Vowels both in isolation and in /bVb/ syllables can be well identified from brief (30 ms) windowed portions taken from the beginning (head) and end (tail) of the syllable [T. Nearey and J. Andruski, J. Acoust. Soc. Am. Suppl. 1 83, S83 (1988)]. Despite similar confusion matrices, formant measurements of windowed /bVb/ data show substantial undershoot compared to initial and final targets of isolated vowels. It is of interest to construct stimuli that are minimally specified but are nonetheless categorized like more complex natural stimuli. Vowels were synthesized with linear transitions based on fundamental and formant frequency measurements from four brief sections of the windowed /bVb/ stimuli. (These sections correspond roughly to transition onset, initial vowel target, final vowel target, and transition offset.) Preliminary listening tests indicate that these simple stimuli are well identified. Results from experiments comparing listeners' error patterns for such minimalist synthetic syllables with those for windowed naturally produced syllables will be presented.
Modeling of contextal effect based on spectral peak interaction
Authors: Akagi Masato
Published: October 2005

This paper presents a model of a lower level contextual effect that can cope with coarticulation problems, especially vowel neutralization. The model is constructed to overshoot spectral peak trajectories based on spectral peak interaction, assuming that the lower level contextual effect is represented as the sum of interaction between each spectral peak pair. The interaction function is determined experimentally in order to reduce the distance between a real spectral peak and its target which is a spectral peak mean computed for vowel uttered in isolation. The interaction function thus determined suggests that: (1) there can be a time-frequency lateral inhibition in the auditory system like that on the retina in the visual system, (2) the interaction function is consistent with the results of psychaocoustic experiments concerning the assimilation and/or contrast effect using paired single formant stimuli, and (3) the contextual effect between adjacent phonemes can be represented as the sum of the assimilation and/or contrast effects between each spectral peak pair. Applying the determined interaction function to real speech data to cope with coarticulation problem, spectral peak trajectories overshoot, spectral peaks at the vowel center approach their own targets, and the distance between each vowel category pair increases.
Geoacoustic properties of the seabed sediment critical to acoustic reverberation at 50 to 500 Hz: A preliminary data set
Authors: Yamamoto Tokuo , Schulkin Morris , Bennett Richard
Published: October 2005

As much as 80% of acoustic reverberation is produced through bottom interactions. Deep-sea sediment have high porosity (or low velocities), therefore, a waveguide is often formed from strong bottom interactions. In addition to the bottom roughness, the random variation in the geoacoustic properties (the compressional wave velocity in particular) of the sediment is responsible for generation of the incoherent propagation/acoustic reverberation. Our existing data [e.g., Bennett et al., Handbook of Geophysical Expro. (1983)] indicate that very strong spatial variations (vertical and horizontal) usually exist in the deep-sea sediments. A preliminary analysis of these geological data by the Biot-Yamamoto theory [Yamamoto and Turgut, J. Acoust. Soc. Am. 83, 1744–1751 (1988)] reveals that strong velocity variations, as much as 20% in velocity magnitude, usually exist in the deep-sea muds at horizontal and vertical scales of 0.3 to 30 m, which is very critical to acoustic reverberation at 50 to 500 Hz. [Work supported by ONR Code 11250 A.]
High-resolution investigations of seismoacoustic propagation in shallow-water areas
Authors: Sutton George H. , Barstow Noël , Carter Jerry A. , Ewing John I. , Harris David
Published: October 2005

Data from a newly developed 30-element accelerometer/hydrophone array are used to study seismoacoustic propagation in shallow-water locations off New Jersey and Martha's Vineyard. The elements of the array have 1-m spacing; each consisting of three orthogonal accelerometers (flat from 2 to 500 Hz), a hydrophone, and a vertical direction sensor. The 120 accelerometer/hydrophone signals and 30 vertical direction signals are digitized and transmitted via 1 km of fiber optic cable to a PC-type recording system. The A/D converters digitize all hydrophones at 2048 samples/s and all accelerometers at 512 samples/s. Good coupling to the bottom is obtained since sensor symmetry has been maximized; coupling to the water has been minimized; and density is matched to the sediments. There are 10-m extensions between the 30-m sensor section and the A/D converter housing at either end of the array. Units containing port-starboard paired, shotgun-shell sources were mounted within the array in these extensions and fired through the array circuitry, providing precise time and distance control and reverse profile capability. Differenced shot pairs emphasize transverse horizontal shear (SH) and Love wave signals; summed pairs emphasize P, SV, and Rayleigh/Stoneley/Scholte waves. Shear boundary wave energy is observed with frequencies greater than 60 Hz and velocities and wavelengths as low as 20 m/s and 1 m, respectively. Considerable energy appears to result from lateral heterogeneity and/or anisotropy. [Research supported by ONR.]
Low-frequency measurements of bottom reflectivity at a thin sediment site in the North Pacific
Authors: Gruber Patricia L. , Dicus Ronald L.
Published: October 2005

Bottom reflectivity measurements were made in the North Pacific, during Pacific Echo I, using a low-frequency, towed source. A MK VI source transmitted 50-s FM sweep signals (5 to 15 Hz) to a vertical array of 16 hydrophones. The FM ramps were deconvolved and beamformed to separate direct and bottom arrivals in time and angle. In addition, ray theory predictions of the arrival structure, scaled by spreading loss, were beamformed. A comparison between the time integrated energy in the measured and theoretical bottom arrivals, led to a measure of the bottom reflectivity. FM ramps were processed along the source ship track to vary the bottom grazing angle from 10 to 75 deg. Reflectivity as a function of bottom grazing angle, smoothed over angle to reduce variance, will be presented. Theoretical computations of reflectivity from a simulated bottom that includes a sediment layer with sound-speed gradient and an elastic basement, with shear and compressional speed gradients and attenuations, will be presented. Theory and measurements are compared to infer the sediment thickness and the wave speed profiles in the upper 200 m of the oceanic crust.
Bottom shear modulus profiler (BSMP) measurements of the shallow-water seabed geoacoustics properties in Japan
Authors: Badiey Mohsen , Yamamoto Tokuo , Suzuki Hideo , Kanai Hiroshi
Published: October 2005

The method of bottom shear modulus profiler (BSMP) was used to measure the seabed properties of several locations in Japan. In this method, the seabed admittance, which is defined as the ratio of the wave-induced particle motion to the wave pressure on the seafloor is measured [T. Yamamoto and T. Torii, Geophys. J. K. Astron. Soc. 85, 413–431 (1986)]. These data are then used as input to a linear inversion scheme for calculation of the shear modulus profile. The collected data are presented in a complete form of shear and compressional wave velocity profiles. An attempt has been made to improve the numerical analysis of the inverse method used in the BSMP software. By applying a tapering Hamming window in the truncation of the order employed in the singular value decomposition (SVD) technique, the truncated expansion equation was modified and the higher-order eigenvalues were used stably. A numerical test as well as the analysis of the data using this method is presented.
Gaussian beam algorithm for bottom reflection and head waves due to extended aperture sources
Authors: Gao X. J. , Felsen L. B.
Published: October 2005

Gaussian beams furnish a useful algorithm for high-frequency sound propagation in complex environments but in their paraxial implementation, they are flawed by spectral defects that obscure certain wave phenomena. Critical reflection and head wave generation due to a fast bottom belong in this category. In a separate study, methods for “fleshing out” the deficient spectrum for the prototype structure of a homogeneous ocean and a homogeneous fluid bottom, have been explored with excitation due to a line source [[X. J. Gan et al., 2nd IMACS Symposium, Princeton University (March 1989)]. In the presentation here, these methods of excitation from a continuously distributed extended aperture source and from an array of line sources have been applied. In the Gaussian beam modeling, not only are the ad hoc discretization that involves arbitrary parameters employed but the self-consistent Gabor phase space stacking are also employed. It is found that distributed sources deemphasize the above-noted spectral defects but do not remove them entirely. [Work supported by ONR.]
Propagation of Rayleigh and Scholte waves along edge of quarter-space
Authors: Chamuel Jacques R. , Brooke Gary H.
Published: October 2005

A surprisingly large leaky Rayleigh wave component has been observed propagating along the edge of a laboratory nonsaline-ice quarter-space in water with both source and receiver positioned along the edge of one of the two surfaces of the quarter-space. Studies on different solids (aluminum, Plexiglas, limestone) indicate that all surface and interface edge waves travel slower than their corresponding waves on a solid half-space. The measured ratio of the edge Rayleigh wave velocity to the half-space Rayleigh wave velocity is 0.9617 for aluminum 6061, 0.9665 for Plexiglas, and 0.9954 for limestone. Ultrasonic experimental results are presented on edge Rayleigh waves, and on edge leaky Rayleigh waves and Scholte waves for the liquid/solid case. The edge wave has no geometrical spreading and dominates the received signal when the receiver is moved slightly away from the water loaded edge of the quarter space. The Rayleigh waves along the horizontal and vertical faces at the edge are out of phase influencing the radiation of the leaky Rayleigh wave for the water-loaded case. Near the edge it is observed that a decrease in the Scholte wave signal is accompanied by an increase in the leaky Rayleigh wave signal. The leaky Rayleigh wave velocity for the water/ice is slightly smaller than the shear wave velocity at the onset of the signal. [Work supported by DREP and ONR.]
Measuremeat of in vivo lung acoustic impedance for animals using random noise and the two microphone technique
Authors: Sneckenberger J. E. , Chandler Cheryl
Published: October 2005

The in vivo acoustic impedance of rats' lungs was measured using random noise and the two microphone transfer function method for calculating impedance. This method eliminates the need for the sensitive pressure transducers used in the conventional measurement of respiratory impedance. Measurements were performed on control rats and rats that had, 5 months prior to the experiments, been exposed to coal dust for 2 weeks. Random noise, flat to 6.4 kHz, was propogated down a three section impedance tube. The experiments began with the insertion of a tracheal tube through the rat's mouth to a depth of approximately 3/4 in. into the trachea. Sound traveling through the impedance tube and tracheal tube and reflecting from the lung was measured with the two microphones and recorded by a two channel FFT analyzer. The analyzer calculated the transfer function between the microphones and, from this transfer function, the complex lung acoustic impedance was calculated. The impulse response was also computed from the transfer function, and was further processed, by the Ware-Aki area inversion algorithm, to produce the effective airway cross-sectional area as a function of depth into the lung from the trachea.
Mindlin's equations of plated, crystal plates for thin-film stress prediction
Authors: Lee P. C. Y.
Published: October 2005

When an electroded, crystal plate is subjected to a steady acceleration and/or a steady, uniform temperature change, stresses are induced due to body forces exerted on the plate and electrodes, and due to the differences in thermal expansions between the plate and electrodes. Based on Mindlin's first-order equations of plated crystal plates [R. D. Mindlin, Progress in Applied Mechanics (Macmillan, New York, 1963), pp. 73–84, Prager Anniversary Volume], a set of six coupled equations is obtained in which the thin-film stresses induced by the body forces and thermal expansions are taken into account. A principle of virtual displacement corresponding to these equations is also obtained. In a partially electroded, circular crystal disk, the stresses due to steady acceleration are calculated, and the changes of thickness-shear frequencies due to these stresses are predicted.
History of the flextensional transducer
Authors: Rolt Kenneth D.
Published: October 2005

Although the invention of the flextensional acoustic transducer is usually attributed to William J. Toulis, it was actually invented at the U. S. Naval Research Laboratories, Washington DC, in 1929 by Harvey C. Hayes. It was intended as a foghorn for the Lighthouse Service. This paper will review Hayes' flextensional from invention to disappearance (c. 1936), and discuss its reinvention and development by Toulis and Frank R. Abbott in the 1950s.
Ultra-high-power superconducting transducers
Authors: Mawardi Osman K.
Published: October 2005

Recent developments in high-temperature superconducting materials make it practical to investigate the feasibility of very high-power super-conducting acoustic transducers capable of generating several hundreds of acoustic kilowatts. A proposed scheme for such a transducer that consists of a variation of a linear motor is described in this paper. Borrowing from the highly developed technology of linear electrical machinery, it is shown that a very compact transducer can be constructed with an energy density one order of magnitude higher than that of a magnetostrictive device. A detailed design and analysis has been completed for a transducer with a rating of 250 kW and an operating frequency of 50 kHz.
Analysis of magnetostrictive transducers by the ATILA finite element code
Authors: Claeyssen F. , Boucher D. , Anifrani K. , Bossut R. , Decarpigny J. N.
Published: October 2005

New magnetostrictive rare-earth-iron alloys offer an attractive opportunity for the design of high-power low-frequency transducers [F. Claeyssen, J. Acoust. Soc. Am. Suppl. 1 81, S89 (1987)]. In order to optimize the design of this particular class of transducers, a model based on a new variational principle has been derived following a classical finite element method approach. This model describes the three-dimensional dynamic behavior of heterogeneous electrochemically coupled structures. Due to the reduced-scalar-potential formulation of the magnetic field, the model has been relatively easily implemented within the ATILA finite element code. In this paper, a general view of the method is given and first computation results on test structures are presented.
Finite element modeling of the ARE low-frequency flextensional transducer
Authors: Brind Richard J.
Published: October 2005

A requirement for underwater acoustic sources with higher source level and wider bandwidth at lower frequencies has, in the past 5 years, lead to interest in flextensional transducers. A low-frequency prototype, which consists of a GRP shell and convention ceramic stacks, has been developed, manufactured, and tested at ARE(Portland); the technology is the subject of a license agreement with industry. In this paper, finite element (FE) analyses performed in support of the prototype development using PAFEC software are described. PAFEC is a commercially available FE package with the facility to model piezoelectric materials, and exterior fluid loading by the doubly asymptotic approximation. In-air and in-water resonant frequencies are well predicted, as is the effect of hydrostatic pressure on stack prestress. The shell is subjected to large interlaminar shear stresses during stack insertion, and predictions for these have also been obtained. Work is in hand at PAFEC to add the capability to couple a Helmholtz integral equation representation for the exterior fluid to the existing finite element package for the structure. This will enable source level and bandwidth calculations to be made, which, at present, cannot be accurately predicted.
Active damping of a piezoelectric crystal designed for airborne acoustic rangefinding
Authors: Kenney Christopher L. , Busch-Vishniac Ilene J.
Published: October 2005

Piezoelectric crystal ultrasonic transducers are ideal for airborne acoustic rangefinding because they are low-damping (high Q) devices capable of producing relatively high sound intensities at a single frequency. However, the low internal damping of the crystal results in substantial ringing, which can interfere with the reflected acoustic signal if left untreated. The conventional means of dealing with the ringing is to passively damp the crystal, but this causes a reduction in efficiency, increases the rise time, and adds substantially to the mass and cost of the transducer. An alternative approach, demonstrated here, is to actively damp the transducer using feedback control. In this system, the piezoelectric disk element is subdivided into two pieces: one large and one small. The small portion is used to sense motions resulting from driving the larger segment. The signal from the sensor is fed through a triggered classical proportional-derivative controller. The controller is triggered so that it is only active when it is desired to quench the crystal motions. Results show that using this controller it is possible to dramatically increase the damping of both the radial mode and the longitudinal mode of the crystal without adding mass to the system, decreasing the transducer operating efficiency, or increasing the rise time. [Work supported by General Motors Research Laboratories.]
Study of the dispersion of the Scholte-Stoneley waves propagating at a plane interface
Authors: de Billy M. , Quentin G. , Franklin H. , Rousseau M. , Gatignol Ph.
Published: October 2005

Theoretical results [Osborne and Hart, J. Acoust. Soc. Am. 17, 100 (1945)] pointed out that for low values of the product Fd (frequency times the thickness of the plate), there exists a dispersion of the Scholte-Stoneley wave as it propagates along the interface between a liquid and a plate. Measurements of the velocity on different materials and for various thickness of the plate reveal a very small dispersion for values of Fd that ranges from 0.5–3 MHz mm. The experimental results will be compared with the theoretical calculations. [Work supported by DRET.]
Acoustic signatures of passive and active targets by the MIIR
Authors: Ripoche Jean , Maze Gérard , Izbicki Jean-Louis , Pareige Pascal
Published: October 2005

The acoustic signatures of elastic targets immersed in water or inclusions in materials are more easily obtained and interpreted since the discovery and implementation, in the 1980s, of the “Method of Isolation and Identification of Resonances” (MIIR) [G. Maze and J. Ripoche, Phys. Lett. A 84, 309–312 (1981); J. Acoust. Soc. Am. 73, 41–43 (1983)] and derived pulse methods. The first interest is the isolation of resonances in quasiline spectra, which are obtained for passive or active targets when the excitation is external or internal. The second interest is the experimental identification of each resonance by the determination of the n mode number, which allows a classification of resonances. The results corroborate the “Resonance Scattering Theory” [H. Überall, L. R. Dragonette, and L. Flax, J. Acoust. Soc. Am. 61, 711–715 (1977)]. Quasiharmonic MIIR and short-pulse MIIR can be applied to cylinders, air- or liquid-filled shells, and multilayered structures (or other targets) immersed in water by means of an external or internal excitation. Experiments give resonance spectra of liquid cylindrical inclusions in elastic materials. [Work supported by D.R.E.T., D.G.A., Contract 86/045.]
Acoustic sampling volume
Authors: Foote K. G.
Published: October 2005

Knowledge of the sampling volume is necessary in many quantitative applications of acoustics. In general, the sampling volume is not merely a characteristic of the transmitting and receiving transducer or transducers, but also depends on the concentration and scattering properties of the target, the kind of signal processing performed on the echo, and the detection threshold. These dependences are stated explicitly in formulas for the sampling volume and a differential measure, the effective equivalent beam angle. Numerical examples are given for dispersed and dense concentrations of both point scatterers and directional fish scatterers.
Stress clash in isolated phrases and sentence contexts
Authors: Cluff Michael S. , Johnson Keith
Published: October 2005

The experiment reported in this paper investigates the possibility that stress clash should be called “accent clash.” Stress clash in the phonological literature has been defined in terms of lexically specified stresses, while experimental investigation of such stress clash candidates has given a mixed picture as regards any phonetic effect of adjacent lexical stresses. The hypothesis was that lexical stress defines the candidates for a clash and that the placement of accents during production determines whether a clash will actually occur. To test this, subjects' productions of pairs of adjective noun phrases that contrasted stress clash versus no stress clash environments (big dinosaur/big dimension) were analyzed. These phrases were recorded both in isolation and within syntactically identical sentence environments. This manipulation was used to elicit two types of accent patterns; in isolation, both the adjective and noun received intonational accent, while in context, only the noun was accented. The results of a pilot experiment have suggested that, for phrases of this type, there is a difference in the durational effect of stress clash (duration of the adjective) when items are produced in isolation versus when they are produced in sentence contexts. The relevance of these data for current phonological theory will be discussed. [Work supported by NIH Research Grant NS-12179 to Indiana University.]
Prosodic aspects of French speech rhythm
Authors: Fletcher Janet
Published: October 2005

A major assumption of the syllable-timing/stress-timing distinction is that interstress interval length in a language like French is a direct additive function of the number of syllables it contains. In stress-timed languages like English, by contrast, interstress interval length is supposed to show a relationship of negative acceleration with increasing syllable number due to an underlying tendency towards the isochronous spacing of stresses. Nakatani et al. (1981), however, showed that interstress intervals are not only positively correlated with intervening number of syllables, there is also no relationship of negative acceleration between foot size in syllables and foot duration. Acoustic timing data for French concur with Nakatani et al.'s findings for English. Accentual phrase duration was highly correlated with the number of syllables that unit contained. Although disyllabic units were not twice as long as monosyllabic units in these French data, this could reflect the fact that rhythmic units in French include a long final syllable due to a right boundary accent. The similarity of these results and those for American English would suggest that apparent compression effects are not a strong argument in favor of one typological description as opposed to another. A further experiment revealed lengthening patterns associated with phrasing that are hierarchical in nature and are compatible with recent models of intonational phrasing proposed for French (e.g., Martin, 1987) and highlight the relevance of accentual grouping in descriptions of French timing.
An articulatory characterization of contrastive emphasis in correcting answers
Authors: Westbury John R. , Fujimura Osamu
Published: October 2005

New recordings of articulatory movements of the tongue, lips, and mandible have been obtained using the University of Wisconsin x-ray microbeam system, from eight normal adult speakers of American English who uttered three-number sequences in question-answer pairs such as “Is it 995 Pine Street? No, it's 955 Pine Street.” Analysis of these data is intended to provide a detailed characterization of the implementation of contrastive emphasis observed in this context. Preliminary comparisons of maximum displacements and peak velocities for the tongue blade and lower lip, during the words “nine” and “five,” respectively, show that both movement parameters increase during a syllable under the influence of contrastive emphasis, but that the relative change in articulator displacement is always greater. This observation is at least partly consistent with results of previous research [Fujimura and Spencer, J. Acoust. Soc. Am. Suppl. 1 74, S117 (1983)], which showed that maximum articulator displacements during emphasized and unemphasized vowels differed more than did certain portions of the movements toward and away from those vowels. [Research supported by USPHS Grant NS-16373.]
Acoustic characteristics of contrastive stress production in normal geriatric, apraxic, conduction aphasic, and dysarthric speakers
Authors: Liss Julie M. , Weismer Gary
Published: October 2005

Contrastive stress drills are often used in speech therapy for persons with neurogenic speech disorders. These drills are designed to have the patient produce heavy stress on a word embedded in a sentence, presumably to maximize articulatory displacement (and perhaps derivatives or results of displacement, such as articulatory velocity or contract). Like many manipulations used in speech therapy, there are no data indicating the efficacy of the technique and, at a more basic level, little data that bear on the phenomena resulting from application of the technique. The purpose of this paper is to describe how vocalic formant trajectories and segmental durations vary as a function of contrastive stress in four groups of speakers. The groups include normal geriatric persons, persons with apraxia of speech, ataxic dysarthria, and conduction aphasia. Results will be discussed relative to the underlying articulatory behavior that is affected by the stress manipulation.
Normative and functional long-term acoustical aspects of English and French men's and women's continuous speech produced normally or with masking noise
Authors: Weiss William
Published: October 2005

An acoustic measure of voice quality was proposed by Frokjaer-Jensen and Prytz [Tech. Rev. (1976)] as α = intensity above 1 kHz/intensity below 1 kHz. Sundberg and Gauffin, [Q.P.S.R. 2–3, (1978)] seemed to suggest that judging higher spectra as a measure of quality is misleading because it could be obtained with an increased vocal effort. They proposed that a measure of good quality is a higher increase of energy in the F0 area relative to the F 1 area (“flow” phonation). The objective of the investigation was to find out how tension, voice quality, and spectra levels are affected under differential masked (that is, functional) conditions for (1) men and women, (2) anglophones and Francophones. It was found that men have significantly higher F1/F0 than women and that Anglophones have significantly higher α than Francophones under masked conditions. However, in spite of the normative differences, the spectral changes were not significantly different between the groups. These results shall be discussed in view of existing theories of acoustic measurements of voice quality.
Surface effects on impact response of lattices
Authors: Tasi James
Published: October 2005

An analytical and computational study is given for the influence of surface conditions on the normal impact response of two identical crystal lattices. Early studies prescribed kinematic assumptions for shock conditions at the surfaces of crystal lattices. These are compared with more recent analysis that uses solutions of the dynamic equations of motion for surfaces to determine the shock condition for impact. In the absence of any surface impurities, long-range attractive forces exist and result in adhesion of the two lattices; during which, large tensile oscillations are generated prior to the advent of a compressive region of impact. The existence of a monolayer of surface impurity on each lattice results in a more traditional shock impact condition if a slightly attractive long-range van der Waals minimum is ignored. If the latter is considered, a combination of adhesion and traditional shock impact condition are found to exist. Asymptotic solutions of the nonlinear dynamic surface equations are given for impact response and related to the early kinematic studies. [Work supported by NSF.]
Characterization of wood for violins
Authors: Haines Daniel W.
Published: October 2005

The top and back of a violin are among the most important components of the instrument, both acoustically and structurally. Centuries ago luthiers identified spruce as the ideal wood of the top and maple as the nearly unanimous choice for the back. This situation holds true today. Why is this so? The answers rests in the mechanical properties of these woods, particularly the properties that characterize the behavior of the top and back in flexural vibration. Five fundamental mechanical properties that hold most of the keys to the acoustical and structural qualities of spruce and maple are (1) density, (2) Young's modulus and (3) damping of waves traveling along the grain, and (4) Young's modulus and (5) damping of waves traveling across the grain. Shear distortion also affects the behavior of the vibrating spruce top and maple back even at low frequencies well within the audio range. Wood selection criteria and the influence of mechanical properties on the quality of the instrument will be discussed.
Effects of boundary conditions on the propagation and interaction of finite amplitude sound beams
Authors: Tjøtta Jacqueline Naze , TenCate James A. , Tjøtta Sigve
Published: October 2005

Weak nonlinearity in the propagation and interaction of real sound beams in a lossless fluid is considered. Special emphasis is given to the effects produced by various boundary conditions at the sound sources and other bounding surfaces. Asymptotic formulas and numerical results are presented for the second harmonic, and for the scattered sum and difference frequency sound generated by two harmonic beams that intersect at an arbitrary angle. The results are derived from a general theory presented earlier [see Naze Tjøtta and Tjøtta, J. Acoust. Soc. Am. 83, 487–495 (1988)], which is valid for any source separation and amplitude distribution. In situations where the parabolic approximation is not legitimate (large angles, broad beams), properly accounting for the boundary conditions may be crucial. [Work supported by the IR&D program of ARL:UT, ONR, and VISTA/STATOIL, Norway.]
Nonlinear elastic response of shocked fused silica
Authors: Gupta Y. M. , Conner M. P.
Published: October 2005

Large amplitude, combined compression and shear wave measurements have been obtained in fused silica (Dynasil 1000) shocked to a peak compressive stress of 6 GPa. The in-material, particle velocity profiles are analyzed to obtain the longitudinal stress-density relation for uniaxial strain and shear wave velocities in the shocked state. The shear wave velocity decreases with compression to a density compression of 7.6%, and then increases with compression. Bulk modulus, Poisson's ratio, and mean stress in the shocked state were determined from the experimental data. Comparison of the shock and hydrostatic compression results show that the fused silica displays reversible, shear-enhanced compaction. Although two of the three third-order elastic constants (C111 and C166) can be calculated from the present data, the difficulty in describing the fused silica response in terms of third-order constants is discussed. A microscopic model to explain shear enhanced compaction is suggested. [Work supported by AFOSR, Grant No. 87-0081 under the DOD/URI program.]
The measurement of thermoacoustic phenomena using thermoacoustic couples
Authors: Atchley Anthony A. , Hofler Thomas J. , Ao Chia-ning
Published: October 2005

The results of measurements of thermoacoustically generated temperature gradients in thermoacoustic couples (TACs) subjected to acoustic standing waves are reported. The value of the temperature gradient is a function of the acoustic pressure amplitude, mean gas pressure, type of gas, TAC construction, and its position in the standing wave. Measurements were made with a computer-controlled apparatus for drive ratios (the ratio of acoustic pressure amplitude to mean gas pressure) from approximately 0.1% to 2.0%, in argon and helium having mean pressures from approximately 0.1 to 0.3 MPa, for three different TACs as a function of their positions in the standing wave. The results are compared with predictions based on a theory by Wheatley et al. [J. Acoust. Soc. Am. 74, 153–170 (1983)]. Three distinct regions of behavior are apparent over the range of drive ratios investigated. For drive ratios less than approximately 0.4%, there is overall good agreement between theory and measurement. For drive ratios between approximately 0.4% and 1%, the agreement diminishes almost linearly with increasing drive ratio. For drive ratios greater than approximately 1%, irregularities appear in the temperature difference data series and the discrepancy between theory and measurement generally remains approximately constant, although some variations occur. [Work supported by ONR and the NPS Research Program.]
Laser ultrasonic measurements in highly porous materials: Sintering of ceramics
Authors: Telschow K. L. , Walter J. B. , Garcia G. V.
Published: October 2005

The use of lasers for both generation and detection of elastic waves in materials has opened the possibility of real-time monitoring of material elastic parameters during processing. At the INEL, a laser Doppler interferometer has been constructed that allows direct measurement of elastic waves from rough and/or optically diffuse surfaces. This apparatus, coupled with a pulsed laser for elastic wave generation, is currently being used for totally noncontacting, real-time, monitoring of the sintering of ceramics. Results will be presented on the densification of materials as a function of sintering time and temperature. Both the longitudinal and shear wave velocities in these materials have been found to vary approximately linearly with the densification up to nearly total theoretical density. Mechanisms of the generation and detection of these elastic waves, as well as propagation in porous materials, will be discussed. [This work was supported by the Department of Interior's Bureau of Mines under Contract No. J0134035 through Department of Energy contract No. DE-ACO7-76IDO1570.]
Mechanisms of abstraction in auditory processing
Authors: Terhardt Ernst
Published: October 2005

The natural purpose of any sensory system is acquisition of information on external processes and objects, i.e., abstraction of the stimulus. Abstraction, in turn, is typically dependent on decisions that are based on internal knowledge. To get more insight into auditory information acquisition—including perception of speech and music—it is thus apparent that particular attention should be paid to decision processes on any level of the auditory system. Inspecting the auditory system from that point of view reveals that both its physical and neurophysiological design and its psychophysical behavior indeed exhibit many cues that are typical of abstraction mechanisms. For instance, extraction of individual “pure tones” from a continuous sound spectrum requires a decision mechanism; therefore, the formation of spectral pitches in the auditory periphery may be regarded as a first step of abstraction. On the basis of a number of experimental data and theoretical arguments, the following questions will be discussed: (1) How is the hierarchy of abstraction organized? (2) Where is the “sensory knowledge” stored? (3) What is the origin of that knowledge? (4) Which strategies of experimental research appear to be appropriate?
Construction of a three-dimensional tongue model
Authors: Wilhelms Reiner
Published: October 2005

A three-dimensional model for the investigation of the dynamic behavior of the tongue is under study. Its purpose is to relate x-ray microbeam-measured movements of pellets on the tongue surface to muscle activity in the tongue, and to generate area functions of the vocal tract in order to specify directly the mapping from muscle activity to acoustic output, As a first step in a finite element description, a reference model of the tongue is constructed that can be adjusted to different individual shapes and structures of the tongue muscles, based on anatomical studies. A schematic topology of the tongue is generated by separating a region of a Cartesian space into simple geometric shapes representing different tissue components. A mapping from this descriptive space to a curvilinear coordinate system using B-splines in three variables is specified to generate a realistic initial shape of the tongue. The orientation of muscle fibers can be determined by normalized gradient fields in the descriptive space.
The front-cavity/F2′ hypothesis tested by data on tongue movements
Authors: Broad David J. , Hermansky Hynek
Published: October 2005

The hypothesis that the second spectral peak F2′ resulting from perceptual linear prediction (PLP) corresponds to the resonance of the front cavity of the vocal tract is tested against data on tongue movements for non-low-back vowels. The front cavity is represented for this case as a uniform tube of length Lf. Scaling between movements of the tongue Δx (range of a few centimeters) and of the vocal-tract constriction ΔLf (range of about 10 cm) is represented by an articulatory amplification factor α: ΔLf = αΔx. If x is a tongue-surface coordinate parallel to the tract axis, then 1/F2′ = k + 4αx/c, where k is a constant and c is the speed of sound. When x is the x coordinate of a tongue-dorsum pellet tracked by x-ray microbeam, the correlations between 1/F2′ and x are 0.74 and 0.75 for two speakers' triple repetitions of /wiwɹjuəjiɹ/. The respective estimates for α are 5.5 and 5.6. The correlations rise to 0.91 and 0.92 if x is a weighted sum of the x and y coordinates of three tongue pellets. Two predictions are thus confirmed: (1) a linear relation between 1/F2′ and tongue movements, and (2) reasonable values for α. A more complex model of the front cavity may be needed to handle low back vowels. [The authors thank George Papçun of Los Alamos National Laboratory for access to his x-ray data.]
The kinematic of final lengthening in French
Authors: Fletcher Janet , Vatikiotis-Bateson Eric
Published: October 2005

In a cross linguistic study of lip-jaw motion, Vatikiotis-Bateson (1988) showed that the kinematic patterns associated with the nonfinal accented-unaccented contrast in French are similar to those found for the stressed-unstressed contrast in English. Opening movements generally have longer durations, greater articulator amplitude, and higher peak velocity when accented than when unaccented. In the current study, the same French corpus is used to investigate final lengthening. Like English, French syllable duration is longer at the edge of intonational phrases than in preceding syllables. Yet, it is not clear what the articulatory correlates of this final lengthening are, nor to what extent they are language-specific. A recent study of final lengthening in English (Edwards, Beckman, and Fletcher, in press) showed that the extra lengthening of pitch accented syllables that are also phrase-final is accompanied by lower peak velocities in the latter part of the syllable with no change in articulator amplitude. However, initial results for French indicate that lengthening in phrase-final syllables, which are always accented, is marked by higher articulator amplitude and peak velocity. Thus the kinematics of final lengthening is qualitatively similar to that of nonfinal accented syllables. The consequences for an articulatory and linguistic timing model of French will be discussed. [Work supported by Ohio State University, NSF, and NIH.]
An evaluation of an alternating magnetic field device for monitoring articulator movements
Authors: Shao Shuyong , Tuller Betty , Kelso J. A. Scott
Published: October 2005

The understanding of articulator coordination during speech has been limited by the type of data that can be safely gathered. Specifically, noninvasive methods of monitoring tongue motions are still not widely available. One promising method is an alternating magnetic field device to track movements of multiple articulators in the midsagittal plane. This report concerns one such commercially available device, the Articulograph AG-100. The principles of system design and operation have been reported previously by P. Schonle and colleagues, in Germany, who developed the system's prototype. Here, an intensive evaluation of system accuracy, repeatability, and linearity, as well as measurements of tongue positioning during speech will be presented. These results indicate that with proper precautions in transducer calibration and placement, the Articulograph can be a useful tool in speech production research. [Work supported by NIH and NIMH.]
Scattering and transmission of sound power flow by solid elastic spheres in water
Authors: Hickling Robert , Burrows R. Kirk , Ball James F. , Redmond Lou Ann
Published: October 2005

The scattering and transmission of sound power flow, or sound intensity, are calculated for plane waves incident on a solid elastic sphere in water. Since sound intensity is the same vector quantity in both the solid and the liquid media, the flow of sound power around and through the sphere can be treated as an entity. In addition to the flow of sound power, distributions of reactive intensity and potential and kinetic energy densities are computed. Extensive use was made of Mathematica in this work. [Work supported by the Office of Naval Research.]