bluuebunny/crossref_metadata_2025 huggingface dataset:
Shedding of vortex rings by collapsing cavities, with application to single-bubble sonoluminescence
Authors: Longuet-Higgins Michael S.
Published: October 2005

Drops of water falling on a plane water surface are known to produce vortex rings which carry vertical momentum away from the surface. A similar phenomenon should also occur in a cavity which collapses asymmetrically: An inward jet will also produce vortex rings on impact with the opposite wall of the cavity. It is suggested that the phenomenon may be taking place on each cycle of collapse of a single sonoluminescing bubble. The transport of jet momentum away from the bubble by the vortex rings should help to restore the bubble, on rebound, to a spherical shape.
Phase diagrams for sonoluminescing bubbles
Authors: Lohse Detlef , Brenner Michael P. , Hilgenfeldt Sascha
Published: October 2005

Sound-driven gas bubbles in water can emit light pulses. This phenomenon is called sonoluminescence (SL). Two different phases of single bubble SL are known: diffusively stable and diffusively unstable SL. Phase diagrams are presented in the gas concentration versus forcing pressure state space and also in the ambient radius versus forcing pressure state space. These phase diagrams are based on the thresholds for energy focusing in the bubble and of (i) shape instabilities and (ii) diffusive instabilities. Stable SL only occurs in a tiny parameter window of a large forcing pressure amplitude Pa∼1.2–1.5 atm and a low gas concentration of less than 0.4% of the saturation. The upper concentration threshold becomes smaller with increasing forcing. The results quantitatively agree with experimental results of Putterman’s UCLA group on argon, but not on air. However, air bubbles and other gas mixtures can also successfully be treated in this approach if, in addition, (iii) chemical instabilities are considered. The essential feature is the removal from the bubble of almost all the nitrogen and oxygen as reaction products (i.e., NOx or NH3). Inert gases are crucial for stable sonoluminescence because they do not react with the fluid.
Cavitation thermometry using molecular and continuum sonoluminescence
Authors: Zakin Mitchell R. , Bernstein Lawrence S. , Flint Edward B. , Suslick Kenneth S.
Published: October 2005

The focus of this study is the use of molecular and continuum emission spectra from multiple bubble (MB) and single bubble (SB) sonoluminescence (SL) as a probe of bubble temperature during cavitational collapse. It is proposed that molecular and continuum SL arise from different chemical pathways, which occur during discrete intervals along the cavitational collapse timeline, and yield different cavitation temperatures. A coupled dynamics/chemical kinetic model of cavitational collapse is developed, and used to explore a variety of proposed molecular SL chemiluminescent reaction mechanisms for the C2 (d→a), CN(B→X), and OH(A→X) emissions. This emission is broadly characterized as originating from reactions involving singly- or multiply bonded molecular precursors with corresponding effective emission temperature ranges of approximately 3000–8000 K and 8000–25 000 K, respectively. The continuum is similar for both SBSL and MBSL; based on the confined electron SL emission model, it is characterized by a temperature range of approximately 20 000–100 000 K. It is concluded that both SBSL and MBSL are consistent with an adiabatic compressional heating description of bubble collapse, and the observed differences in their SL spectra are attributed to the broad initial size distribution of cavitating bubbles for MBSL.
Hydrodynamic solutions for a sonoluminescing gas bubble
Authors: Kwak Ho-Young , Na Jung-Hee
Published: October 2005

Analytic solutions for a sonoluminescing gas bubble have been obtained, which provide density, pressure, and temperature distributions for the gas inside a bubble oscillating under the ultrasonic field. The solutions have revealed that sonoluminescence should occur just prior to the bubble collapse and its duration is less than 300 ps and that increase and subsequent decrease in the bubble wall acceleration induces the quenching of gas followed by the substantial temperature rise up to 100 000 K which can be regarded as a thermal spike. The gas temperature inside the bubble near collapse is determined primarily by the amount of radiation heat loss. Shock formation during the bubble collapse is questionable because gas density, as well as pressure at the bubble center, are much greater than those at the bubble wall during this stage. It also turns out that the number of electrons ionized, the ion species, and the kinetic energy of electrons affect the spectrum of light emission crucially. The spectral radiance calculated is in good agreement with the observed data qualitatively, which suggests that the origin of sonoluminescences is bremsstrahlung rather than thermal blackbody radiation. [Work supported by Korea Science and Engineering Foundation.]
Bubble hydrodynamics and the confined electron model for sonoluminescence
Authors: Bernstein Lawrence S. , Zakin Mitchell R.
Published: October 2005

The origin of sonoluminescence, the conversion of acoustic energy into ultraviolet/visible radiation in liquids, has remained elusive. It is proposed that the emission arises from electrons confined to voids in the hot, dense fluid formed during the final stages of bubble collapse. Such electrons are produced by high-temperature ionization of the bubble constituents. A hard sphere-based model was developed for the fluid structure, thermodynamics, and confined electron emission. The model is consistent with the observed spectral distributions, power output, and time scale associated with emission from single cavitating rare gas bubbles. Effective temperatures during emission in the 200- to 700-nm spectral window are predicted to range from 20 000 to 60 000 K. The consistency of the confined electron model for single bubble sonoluminescence with the observed dynamics of bubble collapse is also explored. The key aspect of this approach is the treatment of the collapsed bubble as a true fluid. The hydrodynamics of bubble collapse are modeled with a modified Rayleigh–Plesset equation using improved formulations for the equation of state and specific heat ratio. Results are presented for the rare gases and related to experimental observations.
Hydrophobic hydration: Water structure around nonpolar solutes and its relevance to a new mechanism for sonoluminescence
Authors: Paulaitis Michael E. , Prosperetti Andrea
Published: October 2005

A clear picture of water structure surrounding simple, nonpolar solutes, such as xenon or argon, has emerged over the past decade from molecular simulations. A confirmation of these results is provided by their ability to explain the unusual temperature dependence of hydrophobic hydration as reflected in pure water by the density maximum observed at 4 °C and the isothermal compressibility minimum at 50 °C. The two factors that determine water structure around simple, nonpolar solutes are: (1) the small size of water molecules and the directional hydrogen-bonding nature of water, and (2) the fact that water molecules can also adopt ‘‘straddling’’ configurations around small solutes in order to maximize the number of hydrogen bonds with neighboring waters of hydration. These preferred configurations give rise to strong solute-water orientational correlations. The presentation will show the importance of these strong solute-water correlations in understanding the molecular nature of hydrophobic hydration and their possible relevance for a new hypothesized mechanism for sonoluminescence. [MEP supported by the National Aeronautics and Space Administration and the National Science Foundation, AP by the Office of Naval Research.]
Observation of mass transport stability and Faraday instability: Why stable single bubble sonoluminescence is possible
Authors: Gaitan D. Felipe , Holt R. Glynn
Published: October 2005

The region of parameter space (acoustic pressure Pa, bubble radius R0) in which stable single bubble sonoluminescence (SBSL) occurs in an air–water system is a small fraction of that which is accessible. This is due to the existence of an island of dissolution at high Pa and small R0. For dissolved gas concentrations above 50% of saturation, the region lies above the threshold for shape oscillations, and is unobservable. Below 50%, an oscillating bubble is stabilized on the boundary of the island which lies below the shape threshold. SBSL is shown to exist exclusively along this boundary. [Work supported by NASA.]
Auditory after-effects revealing adaptive representation of auditory space
Authors: Kashino Makio
Published: October 2005

After-effects refer to distortions of perception following prolonged exposure to a stimulus. In vision, various after-effects have been known for years and have proven to be useful tools in analyzing processing channels of the perceptual system. On the other hand, few after-effects have been reported in hearing. The authors have been studying auditory after-effects affecting sound localization in order to investigate dynamic aspects of auditory spatial representation. It was found that exposure to a sound alters the perceived localization of a subsequent sound, depending on the frequency relationship and interaural time difference (ITD) relationship between the two sounds. It was also found that adaptation to a sound affects the discrimination of ITDs of the following sounds: ITD discrimination is selectively improved in the neighborhood of the preceding sound, and reduced elsewhere. Together, these results indicate that the internal representation of auditory space is not fixed, but adaptive. The responsible mechansims are recalibrated during stimulation so that they can represent recently experienced sounds with the maximum resolution. Such adaptive representations of auditory space provide a basis for efficient information processing of auditory events in the ever-changing real-world environment.
Correlational analysis of acoustic cues for material and motion
Authors: Lutfi Robert A. , Oh Eun Mi , Wang Wen
Published: October 2005

In everyday listening the acoustic attributes of a sound are often used to recover specific information about the sound-producing object or event. In such cases, correlational analysis may be used to study the rules of representation underlying the discrimination of natural sound events [R. A. Lutfi and E. Oh, J. Acoust. Soc. Am. 95, 2967(A) (1994)]. Applications involving two types of natural discriminations, the discrimination of differences in the material composition of two objects, and the discrimination of changes in the motion of a sound-emitting source, are described. Sounds are synthesized according to the principles of theoretical acoustics such that the nominal values of acoustic parameters uniquely identify the material or the feature of motion to be discriminated. Small perturbations about these values are introduced from trial to trial, and partial correlations with the listener’s response are taken as estimates of the degree of reliance placed on each acoustic parameter. The correlations reveal significant differences in individual listening strategies for the same task, but a general tendency to overly rely on one acoustic parameter. The resulting information loss amounts to an 80% reduction in performance efficiency in some cases. [Research supported by NIDCD R01 DC01262-04.]
Detecting time and amplitude jitter in a click train
Authors: Tsuzaki Minoru , Patterson Roy , Lorenzi Christian
Published: October 2005

A series of 2IFC experiments was performed with click trains to determine (a) the temporal jitter and (b) the amplitude jitter necessary to discriminate a regular click train from a jittered click train. The period of the regular click train was varied from 10 ms, where the sound is heard as a 100-Hz buzzy tone, up to 120 ms, where it is heard as a stream of discreet clicks. A fixed percentage jitter was applied to the period (or the amplitude) of each click in the train with positive jitter, negative jitter, and no jitter being given equal probability. The results show that the auditory system is much more sensitive to time jitter (around 12%) than to amplitude jitter (around 50%), and there is a ‘‘hump’’ in the Weber fraction around periods of 40–50 ms between the ‘‘buzzy tone’’ and ‘‘distinct clicks’’ regions. The results are interpreted in terms of the auditory image model of auditory perception [Pattersonet al., J. Acoust. Soc. Am. 98, 1890–1894 (1995)] which preserves phase-locking information in a buffer which is limited to time intervals less than about 40 ms.
Performance measures of the effects of spectral regularity on the perceptual fusion of harmonics
Authors: Roberts Brian
Published: October 2005

A single even harmonic added to an odd-harmonic complex may be judged as more salient than its odd neighbors in a clarity rating task [Roberts and Bregman, J. Acoust. Soc. Am. 90, 3050–3060 (1991)]. For a fundamental frequency (F0) of 100 Hz, this even–odd difference was evident for the highest even harmonic tested (harmonic 8) despite its marginal resolution. This study used similar complexes in a 2IFC procedure. Each interval consisted of a complex tone followed by a pure tone. The frequency of the pure tone matched that of a harmonic in the complex in one interval and was changed by ±0.5*F0 in the other. Subjects were instructed to identify the matching interval. Since the pure tone was heard after the complex tone, it could not cue listening to a particular frequency region. Cross-interval cuing was prevented by changing F0 between the intervals. The procedure used was intended to maximize the effects on performance of differences in immediate perceptual salience between the harmonics. The added even harmonic was typically judged with greater accuracy than its odd neighbors. Furthermore, accuracy declined with increasing harmonic number only for the odd harmonics tested. [Work supported by BBSRC, UK.]
Auditory segregation of simultaneous events based on residue pitch and spectrum
Authors: Divenyi Pierre L. , Algazi Alain P.
Published: October 2005

Simultaneous pairs of 200-ms stimuli were generated in which the two sounds differed in both spectral content and pitch. In one condition, the stimulus consisted of two bandlimited noises of different center frequencies, amplitude-modulated (AM) at two different rates; in another, the two stimuli were sums of sinusoids separated by two different frequencies and had two different spectral weighting functions. In an adaptive 2AFC paradigm, subjects were asked to associate one of the spectra with one of the pitches. Within any block of trials, the two AM- or frequency-separation pitches were held constant. Results indicate that, generally speaking, there is a trade-off between pitch difference and spectral weight difference. Spectral difference thresholds were generally lower for inharmonic than for harmonic complexes. In frequency regions above 2 kHz, however, both the effect of harmonicity and the slope of the trade-off diminish, especially for low-pitch frequencies. [Work supported by NIH and the VA Medical Research.]
Pitch strength of iterated rippled noise
Authors: Yost William A.
Published: October 2005

Two versions of a cascade add, attenuate, and delay circuit were used to generate iterated rippled noise (IRN) stimuli. IRN stimuli produce a repetition pitch whose pitch strength relative to the noise percept can be varied by changing the type of circuit, the attenuation, or the number of iterations in the circuit. Listeners were asked to use pitch strength to discriminate between various pairs of IRN stimuli which differed in the type of network used to generate the sounds, the number of iterations, and the attenuation in the network. A description based on an exponential function of the first peak of the autocorrelation function of IRN stimuli is consistent with the results. The discrimination data were well fit by a function based on the difference in the exponential functions of the first peak of the autocorrelation functions. A magnitude estimation experiment indicated that pitch strength was an exponential function of the height of the first peak in the autocorrelation function. These results suggest that the strength of the pitch of IRN stimuli is based on temporal processing as might be revealed by autocorrelation.
Masking by ipsilateral and contralateral maskers
Authors: Mills John H. , Dubno Judy R. , He Ning-ji
Published: October 2005

Contralateral masking occurs when the threshold of a signal in one ear is elevated by the presence of a masker in the other, contralateral ear. The classic data and theory on contralateral masking were provided by Zwislocki [J. Acoust. Soc. Am. 52, 644–659 (1972)] who observed a 3- to 18-dB threshold shift (masking) for a gated pure-tone signal in one ear when a gated pure-tone masker was presented via insert earphones to the other ear. Zwislocki referred to this phenomenon as ‘‘central masking.’’ Here, using two psychophysical methods (Yes–No; two-interval forced-choice), Zwislocki’s original results, obtained with other psychophysical methods, were successfully replicated. Similar results using several psychophysical methods suggest that contralateral masking is indicative of a sensory phenomenon rather than observer bias and other response proclivities. In a second experiment, psychophysical tuning curves were obtained using either an ipsilateral masker or a contralateral masker. Tuning curves obtained with a contralateral masker had steeper slopes on both the low- and high-frequency sides than tuning curves obtained with an ipsilateral masker. Thus, although substantially smaller in effect than ipsilateral masking, contralateral masking is more sharply tuned. The sharp tuning of contralateral masking reflects a greater compression of the input/output functions for contralateral masking than for ipsilateral masking. The closest correspondence between the tuning curves reported here for contralateral masking and those predicted by Zwislocki’s theory and data (on central masking) occurred for tuning curves where the ratio of driven activity to spontaneous activity was about six. A remaining issue is the role, if any, of the efferent auditory system, especially the olivocochlear bundle, in threshold shifts measured using the Zwislocki (central masking) paradigm.
Normal modes in a continuum model of vocal fold tissues
Authors: Berry David A. , Titze Ingo R.
Published: October 2005

The Ritz method is used to calculate eigenmodes and eigenfrequencies in a continuum model of the vocal folds. The investigation represents a rectification and extension of previous studies, emphasizing the indispensability of utilizing natural boundary conditions when computing the characteristic modes of a system. Concurring with previous assertions, two of the lower-order eigenmodes are theorized to play a major role in facilitating self-oscillation of the folds during phonation. One mode, related to vertical phasing, is shown to have a more direct control over glottal convergence/divergence than indicated in previous calculations. Unlike lumped element models, the continuum model predicts that the eigenfrequencies of the two modes are closely spaced over an extensive range of tissue sizes and stiffnesses. This finding may help explain why the two modes entrain so naturally over a wide range of phonatory adjustments in human phonation.
Chest- and falsetto-like oscillations in a two-mass model of the vocal folds
Authors: Lucero Jorge C.
Published: October 2005

The dynamics of the two-mass model of the vocal fold oscillation is analyzed. It is shown that the oscillation may occur around two equilibrium positions, and that each case presents similar features as the chest and falsetto registers, suggesting a relation between them. The switch between equilibrium positions is caused by a transcritical bifurcation phenomenon.
Glottal volume velocity waveform characteristics in subjects with and without vocal training, related to gender, sound intensity, fundamental frequency, and age
Authors: Sulter Arend M. , Wit Hero P.
Published: October 2005

Glottal volume velocity waveform characteristics of 224 subjects, categorized in four groups according to gender and vocal training, were determined, and their relations to sound-pressure level, fundamental frequency, intra-oral pressure, and age were analyzed. Subjects phonated at three intensity conditions. The glottal volume velocity waveforms were obtained by inverse filtering the oral flow. Glottal volume velocity waveforms were parameterized with flow-based (minimum flow, ac flow, average flow, maximum flow declination rate) and time-based parameters (closed quotient, closing quotient, speed quotient), as well as with derived parameters (vocal efficiency and glottal resistance). Higher sound-pressure levels, intra-oral pressures, and flow-parameter values (ac flow, maximum flow declination rate) were observed, when compared with previous investigations. These higher values might be the result of the specific phonation tasks (stressed /æ/ vowel in a word and a sentence) or filtering processes. Few statistically significant (p<0.01) differences in parameters were found between untrained and trained subjects [the maximum flow declination rate and the closing quotient were higher in trained women (p<0.001), and the speed quotient was higher in trained men (p<0.005)]. Several statistically significant parameter differences were found between men and women [minimum flow, ac flow, average flow, maximum flow declination rate, closing quotient, glottal resistance (p<0.001), and closed quotient (p<0.005)]. Significant effects of intensity condition were observed on ac flow, maximum flow declination rate, closing quotient, and vocal efficiency in women (p<0.005), and on minimum flow, ac flow, average flow, maximum flow declination rate, closed quotient, and vocal efficiency in men (p<0.01).
Reliability of electromagnetic midsagittal articulometry and electropalatography data acquired simultaneously
Authors: Rouco A. , Recasens D.
Published: October 2005

This study evaluates the effects on electromagnetic midsagittal articulometry (EMA) coils from electrode activation on an electropalatography (EPG) artificial palate, and on EPG contact patterns induced by EMA coils. In order to investigate the first issue, five transducer coils on a fixed magazine were placed equidistantly among themselves and with respect to the three transmitter coils of an EMA helmet. Two palate positions were used, i.e., perpendicular to the magazine (to emulate possible effects on coils placed on the nose, upper incisors, jaw, and lips) and parallel to it (to imitate effects on coils placed on the tongue surface). A thin leaf of aluminum firmly pressed by a mold was used to create contact activation. Data for different degrees of contact activation were subtracted from data obtained with no artificial palate (perpendicular condition) or with an artificial palate with zero ‘‘on’’ electrodes (parallel condition). Only for the most extreme condition, i.e., a high degree of contact activation and a short coil-to-artificial palate distance, do the effects slightly exceed the noise level for the EMA equipment. The analysis of the second issue was carried out for coils attached to the tongue tip, the tongue blade, and the tongue dorsum during the production of several consonants. Coil-to-lingual contact effects occur mostly near the midline of the artificial palate at different locations, depending on the degree of contact and the location of the consonant.
A source impedance compensated artificial voice for mask speech intelligibility testing: Thevenin model
Authors: Gerritsen T. A. , Racansky D. O. , Kunov H.
Published: October 2005

This paper describes the development of a Thevenin model of the human voice for mask speech intelligibility testing. The following steps were used to develop the Thevenin model: (1) the long-term average speech spectrum of ten male speakers was measured; (2) the corresponding average vocal tract shape was estimated using linear prediction; (3) a Thevenin model of the voice was determined based on the vocal tract shape. Electroacoustic analogs are used to predict the mask speech spectra produced by the Thevenin model and a mouth simulator consisting of a loudspeaker equalized for free-air speech. Comparing the two spectra allows us to examine how the interaction between the driving point impedance of the voice and the load impedance of a mask affects objective speech intelligibility measurements. The Thevenin model is used in a voice simulator that is described in a future paper.
Response to ‘‘Comments on ‘The coupling of the A0 and the interface Scholte modes in fluid-loaded plates’ ’’ [J. Acoust. Soc. Am. 100, 3442–3445 (1996)]
Authors: Dickey Joseph , Maidanik G. , Uberall H.
Published: October 2005

The authors comment on Dabirikhah and Turner’s [J. Acoust. Soc. Am. 100, 3442–3445 (1996)] treatment of their dispersion curve techniques.
Uniqueness in elastodynamics for systems with nonlocal impedance boundary conditions
Authors: Weaver R. L.
Published: October 2005

It is shown that an elastodynamic initial-value boundary-value problem is unique if the stiffness and mass density are positive definite, and if the boundary conditions are such that the boundary is passive, i.e., that cannot do more work on the body than the body has done on the boundary. This includes impedance boundary conditions of the sort that are now being considered in structural acoustics to represent the effect of uncertain substructures on a known master structure. Uniqueness follows if the impedance is local or nonlocal, in space as well as time. The only requirement is that it be passive.
Comments on ‘‘Uniqueness in elastodynamics for systems with nonlocal impedance boundary conditions’’ [J. Acoust. Soc. Am. 100, 3447–3449 (1996)]
Authors: McCoy John J.
Published: October 2005

The author provides context for Richard Weaver’s uniqueness proof.
Comment on ‘‘Determination of elastic constants of a concrete specimen using transient elastic waves’’ [J. Acoust. Soc. Am. 98, 2142–2148 (1995)]
Authors: Popovics John S.
Published: October 2005

A practical method for the measurement of stress wave velocities in concrete structures is analyzed. Attention is drawn to the fact that caution should be used when estimating the material elastic constants from such results, since elastic moduli values calculated from wave velocities are inappropriate for concrete. Suggestions for the improvement of the experimental technique for wave velocity measurement in concrete are subsequently offered.
Response to ‘‘Comments on ‘Determination of elastic constants of a concrete specimen using transient elastic waves’ ’’ [J. Acoust. Soc. Am. 100, 3451–3453 (1996)]
Authors: Wu T.-T. , Fang J.-S.
Published: October 2005

A response to the comment made by John S. Popovics in a Letter to the Editor commenting on the paper ‘‘Determination of elastic constants of a concrete specimen using transient elastic waves [J. Acoust. Soc. Am. 98, 2142–2148 (1995)]’’ is presented.
Relationships of intensity discrimination to sensation and loudness levels: Dependence on sound frequency
Authors: Ozimek Edward , Zwislocki Jozef J.
Published: October 2005

The main purpose of the experiments described in this article was to establish the frequency dependence of auditory intensity jnd’s (just noticeable differences) for pure tones as functions of loudness level (LL). For this purpose, two sets of experiments were performed. In the first, the jnd’s were measured as functions of sensation level (SL) at sound frequencies of 0.125, 0.5, 1, 2, 4, 6, and 8 kHz. The SLs were set at 10, 20, 40, 60, and 80 dB in a random order. In the second, LLs corresponding to the set of the SL at 1 kHz were obtained, and the relationship of the jnd’s to LL was determined. We investigated to what extent the constant loudness–constant jnd relationship found previously intrafrequency can be applied interfrequency. The detection experiments were performed with a continuous-pedestal paradigm and an adaptive two-alternative, forced-choice (2AFC) procedure that converges on 75% of correct responses. We found that the jnd’s in dB plotted versus SL decreased roughly according to power functions, the rate of decrease depending on sound frequency. The jnd’s increased with sound frequency at low SLs but became practically constant at high SLs. According to the second experiment, the jnd’s followed approximately the same function of LL at all sound frequencies, except for a multiplicative constant, irrespective of the slope of the loudness level function. Thus, the constant loudness–constant jnd relationship appears to apply interfrequency except for a multiplicative constant that, with the continuous-pedestal paradigm, grew monotonically with the frequency.
Phasic and tonic stretch reflexes in human jaw opener muscles
Authors: Ostry David J. , Gribble Paul L. , Levin Mindy F. , Feldman Anatol G.
Published: October 2005

Proprioception plays a fundamental role in human movement. However a number of muscles, including some involved in speech production lack muscle spindles, a primary source of proprioceptive information. In this paper, stretch and unloading reflexes in human jaw opener muscles are described, which have few, if any, spindles. Electromyographic activity was obtained from anterior digastric and masseter and jaw orientation and torque were recorded. The sudden unloading of the jaw opener muscles was observed to elicit a short-latency reflex comparable to that observed in spindle-rich jaw closers but with a longer latency. In addition, the tonic level of muscle activity after unloading was monotonically related to the residual torque and orientation. This is consistent with the idea that the tonic stretch reflex mediates the change in muscle activation. Moreover, the values of joint torque and jaw orientation after unloading were related by a monotonic function resembling the invariant characteristic recorded in the limbs. It is concluded that phasic and tonic stretch reflexes are functionally significant in jaw opener muscles and that the regulation of the thresholds of the tonic stretch reflex of muscles may, as in other musculo-skeletal systems, underlie the control of jaw movements.
Modeling the recognition of sine-wave sentences
Authors: Barker Jon P. , Cooke Martin P.
Published: October 2005

Listeners can recognize sine-wave replicas of utterances synthesized using three time-varying sinusoids [Remez, Science 212, 947–950 (1981)]. Amplitude comodulation of such sine-wave sentences (SWS) further improves intelligibility [Carrell and Opie, Percept. Psychophys. 52, 437–445 (1992)]. In this study an automatic speech recognition (ASR) task investigated two issues. First, is the increased intelligibility of comodulated SWS sentences due to greater resemblance to natural speech? Second, is it necessary to acquire new speech schema for SWS sentences, or can existing schema be accessed using a different strategy? An ASR system was trained and tested on SWS stimuli giving a word recognition rate of 85%, compared to 92% for a system trained and tested on natural speech. Comodulated SWS was recognized at 85%. It appears that the information content of SWS is little below that of speech and is unaffected by comodulation. Testing SWS sentences on models trained on natural speech resulted in low recognition (5%). A second experiment modified the recognition strategy using occluded speech recognition techniques [Green etal ., ICASSP 401–404 (1995)] and gave performance for SWS recognition based on natural utterance models of 46%. These results suggest that SWS recognition does not necessarily rely on acquiring new SWS schemas.
Low-frequency/medium-frequency analysis of a master structure coupled with fuzzy substructures
Authors: Soize Christian
Published: October 2005

Interest has been expressed in predicting the linear vibrations of a complex structure constituted of a weakly damped master structure coupled with weakly damped substructures presenting structural complexity. In the analysis frequency band, the master structure has a modal response (low-frequency behavior) and the substructures have nonmodal responses (medium-frequency behavior). The master structure is modeled by an inhomogeneous anisotropic linear viscoelastic bounded three-dimensional solid continuum. The substructures, which are not accessible to conventional modeling (because details are unknown or are imprecisely known), are modeled within the context of fuzzy structures theory, previously developed by the author. The response of this fuzzy structure is calculated using the Ritz–Galerkin method based on the modes of the master structure. The model of fuzzy substructures depends on parameters which are the dimensionless mean coefficients of participating fuzzy masses. Two methods are presented for estimating these parameters. One is adapted to the identification by experiments, the other one is based on a theoretical approach which uses a mean power flow equation of the fuzzy structures. An example is presented.
Multiple scattering theory for a plate with randomly sprung masses
Authors: Weaver Richard L.
Published: October 2005

The flexural response of an infinite homogeneous plate attached to a random uniform distribution of single degree of freedom undamped oscillators constituting a ‘‘fuzzy substructure’’ is studied theoretically using methods from diagrammatic multiple scattering theory. A Dyson equation is posed for the ensemble average Green’s function, and a Bethe–Salpeter equation is posed for the average of the square of the Green’s function. The Dyson equation is solved within three different approximations: the ‘‘first-order smoothing approximation’’ (equivalent to that of Pierce, Sparrow, and Russell) the ‘‘average T-matrix (or Foldy) approximation,’’ and the self-consistent ‘‘coherent potential approximation.’’ The mean Green’s function is found to be equal to the Greens’ function proposed by Pierce, Sparrow, and Russell, if the individual sprung masses are not large. The Bethe–Salpeter equation is solved within the latter approximation and in the limit that the length and time scales of the diffuse field are long compared to wavelengths and periods. In the further limit that these length and time scales are also long compared to mean-free paths and mean-free times, it is found that the Bethe-Salpeter equation reduces to a diffusion equation. [Work supported by ONR.]
Waves in media with resonant dispersion
Authors: Rybak S. A.
Published: October 2005

Wave propagation in complex media with microstructure is currently receiving a great amount of attention. One approach to modeling such a medium is to assume that each point of the continuum is coupled to a number of oscillators (linearly or nonlinearly). The notion of ‘‘fuzzy structure,’’ currently popular in Western literature, can also be used to describe such media. Some simple examples of structures coupled to oscillators with different parameter distributions are described. The resonant dispersion equation (RDE) is derived and its stationary solutions of different types (including solitonlike solutions) are obtained and analyzed. Generalizations to elastic media with fractures are discussed [S. A. Rybak and Yu. I. Skrynnikov, ‘‘Nonlinear Waves in Resonant Dispersion Media,’’ inNonlinear World, Proceedings of IVIntl . Workshop (World Scientific, 1989), pp. 664–670] [V. N. Alekseev and S. A. Rybak, ‘‘Propagation of Stationary Sound Waves in Media with Bubbles,’’ Acoust. Phys. 41(5), 690–698 (1995)].
Phase and localization length of disordered ribbed systems
Authors: Yang Yang , Photiadis Douglas M.
Published: October 2005

A general integral equation based on Markov chain theory is used to determine the probability density function (pdf) for the phase of vibrational waves propagating along a ribbed flat membrane or plate. This equation is simplified considerably when the ribs are distributed completely randomly or quasiperiodically. In these two cases, the equation is asymptotically solved in the limit of weak or strong scattering from each rib; the phase pdf and the localization factor of the wave functions are obtained explicitly. The validity of the asymptotic solutions is examined and verified by comparing against the well-known analytical solutions and Monte Carlo simulation.
Multiresolution reproducing kernel particle methods in acoustics
Authors: Liu Wing Kam
Published: October 2005

In the analysis of complex phenomena of acoustic systems, the computational modeling requires special attention for a realistic representation of the physics. As a powerful tool, the finite-element method has been widely used in the study of complex systems. In order to capture the important physical phenomena, p-finite elements and/or hp-finite elements are employed. The reproducing kernel particle methods (RKPM) are emerging as an effective alternative due to the absence of a mesh, and the ability to analyze a specific frequency range. In this study, a wavelet particle method based on the multiresolution analysis encountered in signal processing has been developed. The interpolation functions consist of spline functions with a built-in window which permits translation as well as dilation. A variation in the size of the window implies a geometrical refinement, and allows the filtering of the desired frequency range. An adaptivity similar to the hp-finite-element method is obtained through the choice of an optimal dilation parameter. Preliminary analysis of the wave equation shows the effectiveness of this approach. A similar methodology is also developed for the Timoshenko beam.
Wave propagation on flexurally stiff cables with rigid body attachments
Authors: Hayner Mark A. , Vandiver J. Kim
Published: October 2005

The vibration of tensioned cables with flexural rigidity is analyzed in terms of power transmission past a slender rigid body using an exact wave-based method. It is assumed that the cable is made from a linear elastic material, is perfectly straight, and in a vacuum. The results are presented in terms of nondimensional frequency, rigid body mass, and critical frequency at which membrane and flexural stiffness contributions are equal. The results show that transmission is affected as low as a decade below the critical frequency. Flexural rigidity increases the effective bandwidth of transmission and the rocking resonance frequency and is therefore an important consideration for both wide and narrow-band excitations.
Response of mistuned, nonlinear cyclic assemblies to spatially distributed excitations
Authors: King Melvin E.
Published: October 2005

In this work, the dynamics of weakly coupled, nonlinear cyclic assemblies are investigated in the presence of structural irregularities and spatially distributed excitations. A characteristic often found in weakly coupled, repetitive systems is mode localization, arising due to eigenvalue veering in mistuned linear systems and mode bifurcations in tuned nonlinear systems. The occurrence of localized modes in a repetitive system can lead to motions during which vibrational energy is spatially confined to a single substructure (strong localization) and/or several substructures (weak localization). Recent work by the author has investigated the combined effects of nonlinearities and structural mistunings in generating such localized motions. Using the method of multiple scale, the present work considers the response of mistuned assemblies to spatially distributed loading (both harmonic and transient). Under fundamental and/or subharmonic excitation, spatially extended, weakly localized and strongly localized responses are shown to exist for various structural parameters. The physical significance and stability characteristics of these motions will be discussed. Additionally, motion confinement characteristics will be demonstrated under transient loading conditions, and sample calculations will be presented for two, three, and four degree-of-freedom systems subjected to harmonic, base excitation. [Work supported by NSF.]
Relationship of weighted acceleration levels between the ground surface and the floors of a wooden house
Authors: Yokota Akinori
Published: October 2005

For evaluation of vibration which is transmitted to a human body, it is desirable to measure the vibration on the surface at the point of contact with a human body. International standard ISO2631-2 describes measurement/evaluation methods of vibration in a house. In Japan, the ground vibrations caused by road traffic, factory facilities, and construction work have been regulated by law so that the life environment inside of a house can be kept in good condition. However, the regulation law is applied to vibrations measured on the ground surface. The magnitude of vibration on the floor of a house is usually estimated by adding a value of 5 dB to that on the ground surface. This value is a median value of the difference of magnitude of vertically frequency-weighted acceleration between the second floor of a wooden house and the ground surface near the house. The author will compare recently measured data with these data because the amplification value was obtained about 20 years ago and the construction of the house has been changed. Moreover, the difference of the vibration magnitude between that which was estimated by the ISO combined curve and that which was estimated by the conventional curve will be discussed based upon the data measured in the field survey.
Reduction of vibration level in a cabin with a new floating lining system
Authors: Harano Katsuhiro
Published: October 2005

Floating lining systems have been adopted to reduce the noise level in cabins, and the reduction level has been about 10 dB(A) as compared with no floating lining system. The authors pointed out the reason the conventional floating lining systems have poor effects and proposed a concept for a new floating lining system, which consists of a box made of four lining walls and a ceiling set on a floating floor, and the box has as few connecting points with steel structures as possible. In order to promote the system for practical use, experiments were carried out by using a two-third scale model of a cabin. The first experiment with the lining set on a floating floor was carried out without a connecting point to the steel structures, and, in the second step, a rubber piece connected the lining ceiling with the steel structures to prevent lining deformation by the motion of a ship. The second experiment was done to investigate the influence of a connecting point on the vibration level of the lining. As a result, the proposed system could be expected to reduce the vibration level by about 20 dB in the high-frequency range as compared with the conventional floating lining systems.
The process of wave localization in elastic structures of infinite length
Authors: Indejtchev D. A.
Published: October 2005

This article is the first to classify the phenomenon of trapped modes initiation in elastic systems with mass–spring inclusions. Necessary and sufficient conditions for low- and high-frequency trapped modes were found. It is shown then that in elastic systems (beams, plates, shells) which are bounded by a continuous spectrum displaced from 0 and have mass inclusions, a discrete spectrum of natural frequencies occurs before the first boundary frequency. Trapping modes of oscillation corresponding to those frequencies possess a particularly pronounced local character in the inclusions region. The discrete spectrum displacement to the continuous spectrum axis and initiation of high-frequency trapped modes are accompanied by a phenomenon of traveling waves damping (antiresonance).
Trapped modes in elastic structures with mass-spring inclusions
Authors: Andreyev V. L.
Published: October 2005

The authors of the present paper show that specific types of inclusions with certain parameters may significantly change the natural frequency spectrum. In the region of the continuous spectrum may be the real discrete one in that case. The existence of the trapped-wave effect depends on whether the discrete spectrum is located below the boundary of the continuous one or above it. In the case of forced oscillations, resonances occur near the inclusions. If the active load is orthogonal to the traveling modes of oscillation, trapped waves are absent. For the first time it has been found that the trapped-wave effect appears at some frequencies which are equal to the natural frequencies of a certain part of the elastic structure.
The supraformant hypothesis for vowels: Evidence from Norwegian
Authors: Lowenstein Joanna H. , Landahl Karen L. , Ziolkowski Michael S. , Viechnicki Peter D.
Published: October 2005

In contrast with English, examination of spectrograms of Norwegian vowels indicated that traditional formant measurements [Peterson and Barney, J. Acoust. Soc. Am. 24, 175–184 (1952)] were inadequate to characterize its nine long-vowel categories. Given Norwegian’s distinct patterns of formant convergences and attenuations, it is hypothesized that spectral shape is better described by supraformants, second-order acoustic structures shaped by formant structure. Supraformants quantify the continuous spectral shape into distinct peaks associated with each vowel category. Schematic supraformant patterns for Norwegian have been previously reported [J. Acoust. Soc. Am. 98, 2966 (1995)]. Here 387 tokens of Norwegian vowels from 12 native speakers were analyzed (two children, four males, six females). For each vowel token, an LPC plot of peak frequency versus bandwidth was generated with the filter-order set intentionally low in an attempt to extract supraformants instead of formants. The resulting data set for each vowel was subjected to cluster analysis to assist in quantifying the supraformants. Analysis of the vowel tokens for one adult male speaker [Proceedings of the Chicago Linguistic Society 32 (to be published)] demonstrated that observed clusters correspond closely to the posited supraformant patterns. This study extends the analysis method to the entire corpus of data.
Acoustic characteristics of perceived vowel quantity and quality in English and Norwegian vowels
Authors: Nylund Anne , Behne Dawn M.
Published: October 2005

In Norwegian and English, as in many languages, vowels can be characterized in terms of distinctive phonological vowel quantity and vowel quality. Norwegian is described as having a phonological distinction between long and short vowels, whereas in English vowel quantity is generally seen as more distinct. However, both vowel quantity and quality can acoustically be realized in vowel duration and the accompanying characteristic resonance of a vowel. The goal of this project is to examine the perceptual weight of vowel duration and the first two formant frequencies for Norwegians when hearing Norwegian vowels versus English vowels. Six sets of words were resynthesized based on three Norwegian vowel pairs and three English vowel pairs. The words in each set were resynthesized using the members of the pair as the end points of a matrix with five degrees of vowel duration and five degrees of F1 and F2 adjustment. Based on judgments by native Norwegian listeners, results to date suggest that native listeners of Norwegian will be more perceptive to differences in vowel duration than to spectral characteristics. Results for the English and Norwegian vowels will be compared and discussed in terms of native language influence on vowel perception.