bluuebunny/crossref_metadata_2025 huggingface dataset:
Function and structure of the avian peripheral auditory system
Authors: Sachs Murray B. , Smith Catherine A.
Published: October 2005

Studies of the function of the avian peripheral auditory system originated with cochlear microphonic recordings from pigeon by Wever and Bray in 1936. More recently, there have been several studies of the response properties of avian auditory-nerve fibers; these will form the basis of our review of the function of the avian periphery. In many respects, the characteristics of avian auditory-nerve fibers are quite comparable as is the precision of phase-locking to low-frequency tones. On the other hand, there do appear to be significant differences. For example, tuning curves of avian auditory-nerve fibers seem to lack the low-frequency tails found in tuning curves of mammalian fibers. Rates of driven and spontaneous activity are higher in birds than in mammals. Spontaneous activity of many avian fibers can be suppressed by appropriate single tones, whereas single-tone suppression has rarely been reported in mammalian auditory-nerve fibers. In light of these similarities and differences in function, it is instructive to consider similarities and differences in the structure of avian and mammalian inner ears. The bird's receptor organ is small and covered with a compact mass of sensory cells. Different kinds of hair cells with afferent and efferent nerve endings have a distinctive organization on the basilar membrane. The dimensions of the short basilar membrane (2–4 mm) and locations of hair cell types varies in parakeet, sparrow, pine siskin, pigeon and chicken. Their behaviorally derived audibility curves have short frequency ranges each with a sharp sensitivity peak. The barn owl's sensitivity is good over a considerably wider range; it has a 12-mm-long basilar papilla with an unusual hair cell arrangement.
Neural processing of temporal information in auditory stimuli
Authors: Hind Joseph E.
Published: October 2005

Microelectrode recordings from single auditory nerve fibers in a variety of species have fully confirmed the basic assumption of the volley theory that stimulus periodicity is reflected in the rhythm of neural discharges. In response to low-frequency pure tones, discharges occur preferentially during a restricted segment of the sinusoidal cycle. For such phase-locked responses the time intervals between discharges are grouped around integral multiples of the period of the tone. Thus the array of active fibers conveys to the central nervous system (CNS) information in the form of a period time code. There is abundant physiological and psychophysical evidence that the CNS utilizes minute differences in the timing of the period codes from the two ears to localize a sound source in space and to improve the discrimination of a binaural signal in the presence of noise. While there are no direct physiological findings on the question of whether the CNS uses the period time code to extract information about stimulus frequency, psychophysical results have led several theorists to postulate an affirmative answer. [Supported by NINCDS grant NS12732.]
Generation of hair cell receptor potentials and basilar membrane tuning
Authors: Sellick Peter M. , Russell Ian J. , Patuzzi Robert , Johnstone Brian M.
Published: October 2005

Inner hair cell (IHC) receptor potentials recorded from the first turn of the guinea pig cochlea phase-lead the extracellularly recorded cochlear microphonic indicating a response during basilar membrane velocity towards scala vestibuli. This phase-lead was reduced for higher frequencies, faster than could be expected from the effect of the membrane time constant alone suggesting that the IHCs changed from responding to velocity, to displacement. In order to resolve this question period histograms were generated from single units recorded in the spiral ganglion to frequencies between 40 and 500 Hz. Cells responded at low intensities during displacement towards scala tympani and at higher intensities this response changed to scala vestibuli velocity. We interpret this as being the effect of cochlear microphonic generated by the outer hair cells on the IHC synapse and the IHC receptor potential respectively and conclude that IHCs respond to basilar membrane velocity at least up to 500 Hz. Using the Mossbauer technique we have measured basilar membrane vibration at low sound pressures. The measurements were performed on guinea pigs at about the 18-kHz point in a fluid-filled scala tympani. The results show strong nonlinearities and sharp tuning, both of which are very vulnerable. There is a direct relationship between basilar membrane velocity and neural thresholds over a 60-dB range. This suggests that only minor processing takes place between basilar membrane vibration and hair cell stimulation.
Theoretical basis for the perception of acoustic stimuli by the mammalian brain: CNS-endogenous microwave fields
Authors: Stocklin Philip L.
Published: October 2005

Endogenous microwave fields are those radiated by changes in rotational energy state of proteins integral to neural membranes. Previous electromagnetic analysis [P. L. Stocklin and B. F. Stocklin, T.-I.-T. J. Life Sci. 9, 29–51 (1979)] and data review [P. L. Stocklin and B. F. Stocklin, Physiol. Chem. Phys. 13, 175–177 (1981)] have developed properties of characteristic modes supported by the adult human brain/skull cavity, whose frequencies lie within the protein rotational frequency band. Basic physical theory is reviewed, then applied to acoustic stimulus perception. When neurally stimulated, the primary auditory cortex (AI) acts as a modal source region. Within AI, tonotopicity matches the orderly variation of mode energy partitioning as source location is changed. Elsewhere within the auditory cortex, modal properties support the absence of strict tonotopicity. Transverse electric field modal patterns and rank-ordered modal energy analysis are used to relate modal properties to the following properties of hearing: perceived difference between acoustic tones of different frequency, two-tone consonance/dissonance, and frequency variation of minimum audible signal level.
Survey of cochlear implant work
Authors: Müller Carl G.
Published: October 2005

The cochlear implant has recently seemed useful enough to be considered by some as a clinical procedure. This paper presents a review of the progress made on cochlear implants worldwide. Data are presented which contrast the results obtained in different labs on similar tests: threshold detection, pitch and loudness scaling, chronaxie, and difference limen tests. Models to account for some of these results are given. Four centers (San Francisco, Vienna, Salt Lake City, and Melbourne) have reported surprisingly good speech comprehension scores. We discuss the psychoacoustic characteristics which may relate to these scores and demonstrate that many implant patients show results which are expected quite typically in cochlear dysfunction. Thus the limits on speech processing in the hard-of-hearing may apply as well to implant patients, regardless of the method of speech coding. We also stress the lack of evidence confirming the assumed greater usefulness of multi-channel implants over single channel devices. Finally, a careful look is given to the risks involved in these procedures, specifically those of bone and tumor growth, device replacement, and the psychological effects from device failure.
Heterofrequency vibrotactile masking functions predicted from a duplex model
Authors: verrillo Ronald T. , VanDoren Clayton L. , Gescheider George A.
Published: October 2005

Vibrotactile thresholds were measured at a single site on the thenar eminence in the presence of maskers set at different sensation levels. Measurements were made using a two-interval, forced-choice tracking paradigm. Maskers, either narrow-band random noise or sinusoids, were presented simultaneously with test stimuli of different frequencies. Predictions of threshold shifts as a function of masker intensity were made for individual subjects based on their absolute vibrotactile thresholds and a duplex model of mechanoreception. The results showed that masking occurred within either the Pacinian or non-Pacinian receptor system, but masking virtually disappeared when masker and test stimulus occurred in different channels. [Work supported by NIH.]
Normal mode propagation through sound speed fluctuations
Authors: Koch Robert A.
Published: October 2005

A systematic mode coupling theory is described. The theory, besides treating the coupled mode problem for slow variation in the gross features of sound speed profile and waveguide boundaries, allows small sound speed profile fluctuations on short scale-lengths, i.e., for scales on the order of an acoustic wavelength. The theory shows energy to be conserved. A statistical treatment of the sound speed fluctuations, when appropriate, may be applied and is illustrated with a simple example which demonstrates the effect of the sound speed fluctuations on the sound field phase content. [Work sponsored by Naval Ocean Research and Development Activity.]
A coupled-mode model for spatial coherence of bottom-interacting energy
Authors: Dozier Lewis B.
Published: October 2005

In many low-frequency situations a significant amount of energy is returned from the ocean bottom. The spatial coherence of this energy then determines whether it is useful for signal processing systems. In this paper we address the issue of coherence loss due to range-dependent variations in sediment properties; in particular, sediment sound speed variations are found to drive the problem. Since such data are sparse, and since it is the scale lengths of the variations which are important, we model the sound speed variations as a random process. We then extend a coupled-mode theory of stochastic wave propagation previously developed for random internal waves in the water column by Dozier and Tappert [J. Acoust. Soc. Am. 63, 353–365 (1978) and 64, 533–547 (1978)] to include spatial coherence (and transmission loss) in this case. Asymptotic infinite-range limits, derived from a limiting shape of the modal energy distribution, are also given. [Work supported by NORDA Code 500.]
Fluctuation time series and spectra of signals received on bottom-mounted hydrophones
Authors: Dicus Ronald L. , Hayward Thomas
Published: October 2005

Measurements of the log-intensity signal received on bottom-mounted hydrophones at a depth of approximately 3500 m were examined as fluctuation time series. A 14-Hz cw source was towed at a depth of 135 m along broadside radial and transverse arc courses at ranges from 500 to 1000 km. Deep nulls (10–15 dB) in the time series characteristic of radial source tows were also observed in the are tows. Averaged fluctuation spectra (resolution = 0.23 h−1) were characterized by two peaks (0.23 and 0.69 h−1) for the are spectrum and by a single peak at a frequency midway between the arc peaks for the radial spectrum. The peaks shifted upwards in frequency by a factor of 2 for the arc spectrum and by a factor of 1.5 for the radial spectrum as the source distance decreased from 1000 to 700 kin. Possible effects of environmental cylindrical inhomogeneity, including interaction with a laterally heterogeneous bottom, are discussed with the aid of parabolic equation algorithm computations.
Scattering of an elastic wave by a surface-breaking crack
Authors: Mendelsohn Daniel A. , Achenbach Jan D. , Keer Leon M.
Published: October 2005

Scattering of incident surface waves and incident body waves by a surface-breaking crack in a homogeneous isotropic elastic solid is investigated in a two-dimensional geometry. By decomposing the scattered fields into symmetric and antisymmetric fields with respect to the plane of the crack, two boundary value problems for a quarter-plane have been obtained. The formulation of each boundary-value problem has been reduced to a singular integral equation which has been solved numerically. For incident surface waves the exact backscattered and forwardscattered surface waves have been plotted versus the dimensionless frequency. An asymptotic approximation to these surface motions for high frequency is also presented as a function of dimensionless frequency. Curves are also presented for the exact scattered displacement fields in the interior of the body generated by incident body waves, both versus the angle of incidence and versus the dimensionless frequency.
Scattering of elastic waves from double defects in solids
Authors: Tittmann B. R. , Cohen-Tenoudji F. , Ahlberg L. , Quentin G.
Published: October 2005

Scattering of longitudinal waves from double defects embedded in Ti alloy is discussed in terms of comparisons between experimental and theoretical results. Results are presented for two overlapping cavities, two adjacent cavities, a cavity with a circular crack, and an inclusion with a crack at one side. The data are discussed for both the time and frequency domains. An effort is made to identify significant features by ray tracing arguments. The results cover the range of ka from 0.g to 4, where k is the ultrasonic wave factor and a is the radius of the main defect. [This work was in part supported by the Center for Advanced NDE operated by the Ames Laboratory USDOE, for DARPA and AFWAL/AFML under Contract No. W-7405-Eng-82.]
Thermal wave microscopy of doped silicon crystals
Authors: Farrow R. C. , Thomas M. K. , Joy D. C.
Published: October 2005

Thermal wave microscopy in the scanning electron microscope offers profiling studies of semiconductors that is inexpensive and nondestructive. The technique monitors the sound induced by the thermoelastic effect of a pulsed electron beam in solid samples. Sound is detected by a piezoelectric transducer on which the sample is mounted. The thermal wave signal is critically damped and extends only one wave length below the surface. Variations in the thermal properties of the material within the range will change the amplitude and phase of the thermal wave and hence of the ultrasonic signal that this produces. A depth profile can therefore be deduced by such measurements. In this paper, preliminary results of a study of doped silicon samples are presented. Differences in sound amplitude between doped and undoped regions are related to thermal conductivity differences. The amplitude difference as a function of phase and frequency will also be discussed with the aim of clarifying the nature of the depth sensitivity of the technique by a comparison with existing theories.
Velocity and attenuation in saturated glass beads
Authors: Plona T. J. , Johnson David Linton
Published: October 2005

Based on the Biot theory for propagation of sound in a fluid-saturated porous medium, the velocity and attenuation of compressional waves has been studied as a function of frequency in water-saturated unconsolidated glass beads. We have made ultrasonic measurements in the 200 kHz to 5 MHz range on a collection of samples of mono-sized spheres with mean particle size ranging from 20–500 μm. The measured attenuation is shown to be in agreement with theory both in magnitude and in frequency dependence in the high-frequency limit where an ∫1/2 behavior is predicted. in this range, the loss increases as permeability decreases. For the smallest size particles, the low-frequency transition to an ∫2 behavior in the attenuation is also observed as well as the predicted velocity dispersion. For all the samples, high enough frequencies were used in the measurements such that scattering effects were observed. Thus, the transition from nonscattering (Biot) losses to scattering losses will also be discussed. An interpretation of the scattering loss in terms of multiple scattering has been discussed elsewhere [H. Levine et al., Proc. Seventh Annual Midwestern Mechanics Conference (1981)].
An ultrasonic light diffraction technique for studying acoustic wave propagation in air above 1 MHz
Authors: Riley Ward A. , Love L. Alan , Griffith David W.
Published: October 2005

Studies of ultrasonic light diffraction above 1 MHz in bulk media have normally been conducted in liquids and solids due to the difficulty of generating and propagating ultrasonic waves in gases. A sensitive broadband optical diffraction technique has been used to study the propagation of ultrasonic waves in air in the low megahertz frequency range. An ultrasonic beam at 1.4 MHz was produced in air by driving a medical ultrasound transducer (circular face, unfocused, 13-mm diameter) with a narrowband rf pulse having a peak potential amplitude of 300 V. The radiated waveform and power of approximately 30 mW was detected with a 1-mm-diam laser beam from approximately 2–30 mm from the transducer face. The fundamental frequency was found to experience an attenuation of −4.1 dB/cm over this range. A significant amount of the second harmonic was observed to be generated over this path length demonstrating the presence of nonlinear acoustical phenomena. This technique could be useful for studying the fundamental propagation characteristics of ultrasound in gases above 1 MHz and for the analysis of broadband acoustic pulses having significant frequency content above 200 kHz. In practical application, it should be possible to place an upper limit on the acoustic power levels radiated into air by medical diagnostic pulse-echo systems with this approach. [Work supported by NIGMS 27755.]
Effects of static and dynamic stress on the piezoelectric and dielectric properties of PVF2
Authors: Meeks Steven W.
Published: October 2005

The effects of hydrostatic stress on the piezoelectric constants d33, g33, and the dielectric constant K33T of thick film EMI PVF2 are investigated. The results show that the non-voided form of thick film PVF2 suffers little degradation at pressures of 70 MPa. The voided form of PVF2, although suffering considerable degradation at 25 MPa, still exhibits acceptable properties at this pressure. Data are also presented on the effects of static stress cycling on the material constants of voided and nonvoided thick film PVF2. The nonvoided form can withstand repeated cycles to 70 MPa without progressive degradation. On the other hand, the voided sample will only withstand repeated pressure cycles to 25 MPa. The linearity of these materials was also determined to show considerable nonlinearity for the voided samples. The application of PVF2 as a shock sensor was also discussed.
A bootstrapping training technique for obtaining demisyllable reference patterns
Authors: Rabiner L. R. , Rosenberg A. E. , Wilpon J. W. , Zampini T. M.
Published: October 2005

The process of obtaining reference patterns for syllablelike units is tedious and time-consuming. As such, speech recognition systems based on such units are usually tested on only a single talker. In this talk we describe a procedure for using demisyllable reference patterns excised from spoken utterances for one talker, and automatically creating demisyllable reference patterns for a new talker. The procedure is based on dynamic time-warping alignment of the spoken utterances, and the assumption that the optimum warping path identifies the best matching demisyllable within the utterance. The procedure has been used to create demisyllable reference patterns for two new talkers. Recognition tests were performed using the automatically created references with both a 100- and 1109-word vocabulary. Word accuracies greater than 90% were obtained for both talkers on the 100-word vocabulary. Using the 1109-word vocabulary, it was shown that the recognition accuracy using the automatically extracted demisyllables was only slightly worse than the recognition accuracy from reference patterns based on hand corrections applied to the demisyllables.
On the generation of underwater ambient noise
Authors: Li H.
Published: October 2005

A general differential equation for noise generation can be derived from the continuity and momentum equations of fluid mechanisms for regions that include both mass and force sources. This equation is an inhomogeneous wave equation, and the solution is given in the form of surface integrals and volume integrals. The solution is more general than the solutions given in the literature. For example, if the source terms and the boundary effect are neglected, we have the result of Lighthill. The interpretation of the various sources of noise is presented. As for underwater ambient noise, the implication of wind-induced noise and ship-generated noise are given. The existing theories of wind-induced noise and the most likely theory for various frequency ranges are identified. The limitation of various theories and the availability of noise measurement are discussed.
Effects of repitition rate and impulsiveness on annoyance due to simulated helicopter rotor noise
Authors: Powell Clemens A. , McCurdy David A.
Published: October 2005

Annoyance judgments of 82 different simulated helicopter impulsive rotor noise stimuli were obtained in an anechoic chamber to examine effects of repetition rate and impulsiveness. The stimuli were generated by computer from predicted Fourier harmonic structure with amplitude and phase components corrected for effects of the audio reproduction system. Impulse repetition rates covered a range from 10 to 115 Hz; crest factors covered a range from 3.2 to 19.3 dB. Each stimulus was judged at three sound pressure levels by 48 subjects. Judgments were converted from a continuous numerical annoyance scale to a decibel like scale by comparing them to judgments of annoyance of a 115-Hz tone presented over a wide range of sound pressure levels. Increases in annoyance with increases in repetition rate were found which were not predicted by common loudness or annoyance metrics and which were independent of noise level. The ability to predict effects of impulsiveness varied between the noise metrics, and was found to be dependent on noise level. The ability to predict the effects of impulsiveness was not generally improved by any of several proposed “impulsiveness corrections.” Instead, the effects of impulsiveness were found to be systematically related to the frequency content of the stimuli. A modified frequency weighting was developed which offers improved annoyance prediction.
Effect of tactile vibration on annoyance to synthesized propfan noise
Authors: Clevenson Sherman A. , Dempsey Thomas K.
Published: October 2005

A research program at NASA-Langley Research Center is being conducted to provide design information that maximizes passenger comfort for proposed propfan aircraft. Particular emphasis in this study is being placed on predicting noise and vibration environments and the resultant passenger acceptability. Previous ride quality research of this program has indicated that vibrations of sufficient intensity to produce whole body movements (at frequencies less than 30 Hz) cause passenger discomfort and annoyance. Within this complex interior environment, this type of vibration interacts additively with noise to produce discomfort. However, recent questions have arisen concerning the effect of high frequency tactile vibration (i.e., greater than 30 Hz) on passenger reactions. The current study addressed this question through obtaining passenger reactions to a wide range of noise and tactile vibration environments. The investigation was conducted in the passenger ride quality simulator located at the NASA-LaRC using 96 subjects who evaluated either synthesized propeller noises only, or these noises combined with seat/arm vibration. The noises ranging from 80–100 dB consisted of a turbulent boundary layer noise with a factorial combination of five blade passage frequencies (50–200 Hz), two harmonic rolloffs, and three tone/noise ratios. The results indicate that passenger reaction (annoyance) to noise is not significantly changed in the presence of tactile vibration.
Scattering of waves by obstacles embedded in a half-space
Authors: Varadan V. V. , Varadan V. K.
Published: October 2005

In many practical applications it is important to understand the effect of nearby boundaries on the scattering response of the obstacles. Even the introduction of a plane boundary, i.e., embedding the obstacle in a half-space rather than in an infinite medium causes a significant change in the scattered field and at the same time presents a mathematical challenge except for the case of scalar waves. We employ a self-consistent multiple scattering approach to study the response of the half-space on the scattering cross section of the obstacle. The approach calls for expanding the exciting and scattered fields in a suitable set of basis functions with unknown expansions coefficients α and β, respectively. For closed obstacles, β is related to α through the T matrix. For planar boundaries, α and β are related through the reflection (R) matrix. After defining expansions for the exciting and scattered fields and relating α and β through the R or T matrices, one simply ends up with a system of coupled matrix equations which may be solved in a straightforward manner.
Verification of an acoustic transmission matrix analysis of sound propagation in a variable area duct without flow
Authors: Miles J. H.
Published: October 2005

An acoustic transmission matrix analysis of sound propagation in a variable area duct with and without flow was recently published [J. H. Miles, J. Acoust. Soc. Am. 69, 1577–1586 0981)]. In this analysis the differential equations governing the propagation of sound in a variable area duct are put in state variable form using acoustic pressure and particle velocity as the state variables. The duct is divided into a number of regions. The region size is selected so that in each region the area variation can be approximated by an exponential area variation. The transmission matrix for each region is obtained by solving the resulting constant coefficient acoustic state variable differential equation. This analysis is compared with an experimental standing wave pressure and phase angle profile obtained at 1560 Hz in a study of sound propagation without flow in a 1.4-m-long hardwall rectangular duct containing a 0.0762-m region of converging-diverging area variation [K. Baumeister et al., AIAA J. 81, 2016 (October 1981)]. The analysis is shown to be in excellent agreement with the data.
Acoustical behavior of a submerged steel plate coated with an elastomer layer that contains perforations
Authors: Rudgers Anthony J. , Solvold Christine A.
Published: October 2005

The reflection and transmission characteristics of an infinite steel plate submerged in water are analyzed for a normally incident plane acoustic wave. The plate is coated on one side by a layer of styrene-butadiene rubber (SBR) perforated by a doubly periodic array of rectangular holes. A second, thin, homogeneous SBR layer covers the perforated layer so as to exclude water from the holes. Numerical analyses are presented that compare two different models describing the perforated layer—the “effective-modulus” model and an alternative model derived using an approximate elasticity-theory analysis. In the effective-modulus model, only the volume concentration of the perforations in the SBR affects the elastic properties of the layer. However, in the alternative model, the layer elastic properties are affected by the size, shape, and pattern of the perforations, in addition to their concentration. The effects of perforation size, shape, and pattern are illustrated by comparing computed results for different perforation schemes having the same volume concentration of perforations.
Development of an acoustically transparent plastic for underwater applications
Authors: Thompson Corley M. , Griffith James R.
Published: October 2005

There are many potential underwater applications for a rigid acoustically transparent material. Mounts for a piezoelectric polymer calibration array, hydrophone encapsulants, and sonar transducer windows are but a few of the possibilities. A new class of structural materials has recently been developed that provides a sound speed and density match with water. These materials are a composite of glass microballoons with a class of fluoroepoxies based on the diglycidyl ether of 1,3-Bis(2-hydroxyhexafluoropropyl)-5-perfluoroalkylbenzene. Sound speeds and densities of the cured, unfilled fluoroepoxies depends upon the size of the perfluoroalkyl side chain. Measurements performed at 1–4 MHZ frequency range showed that the sound speed ranged from ca. 2020 m/s for a compound with no side chain to ca. 1450 m/s for an eight-carbon side chain material whereas their densities fell in the range of 1400–1500 kg/m3. The addition of glass microballoons to the fluoroepoxy resin caused a slight increase in sound speed, but a drastic decrease in density. This technique yielded a rigid material that exhibits excellent water resistance as well as a close match in both density and sound speed with water.
Vibration maturity of the Space Shuttle Main Engines
Authors: Larson E. W. , Mogil E.
Published: October 2005

The initial structural design of the Space Shuttle Main Engine was capable of withstanding all known shock and vibratory loads to be encountered during its useful life. However, during the development stage, some unexpected dynamic loads were uncovered that required redesign. The successful incorporation of the knowledge of shock and vibration loads gained during the development of these engines led directly to the first successful flight, and will ensure future successful flights of the Space Shuttles. This paper is a review of the development of the SSME zonal vibration criteria, laboratory vibration tests using zonal criteria to verify life of engine components, and the resolution of unexpected structural problems in turbine blades and in the main injector LOX post due to hot gas flow. Hardware modifications were made to resist the dynamic loads associated with the vibration environments and the hot gas flow until long lead time redesigns could be incorporated. This experience and knowledge will be useful to the design of future liquid rocket engines.
Sternohold activity during utterances containing three classes of voiceless stops
Authors: Dent L. , Niimi S. , Lisker L.
Published: October 2005

Meaningful Bolivian Quechua utterances, each containing one of three classes of voiceless stops (unaspirated, aspirated, and glottalized), were spoken by a phonetician who attempted to imitate the productions of the same utterances by a native Bolivian. Electromyographic recordings from the sternohyoid muscle (SH) reveal that three relatively independent factors influence the height of peaks in SH activity: vowel stress, vowel identity, and stop manner category. A peak in SH activity is associated with voice onset for the vowel following release of oral stop closure. (Consequently, for a vowel following an unaspirated stop, the peak is nearly coincident with oral release; the peak is delayed relative to release of aspirated and glottalized stops.) Ceteris paribus, SH activity peaks higher for stressed than for unstressed vowels. For equally stressed vowels, the peak at voice onset is higher for /u/ than for /i/ than for /a/. Given the constant vocalic environment /ay_'u/, the SH activity peak at voice onset following the stop of interest is highest following aspirated stops, next highest following glottalized stops, and lowest following unaspirated stops. [Work supported in part by NINCDS and NIDR.]
Vowel articulation and laryngeal control in the speech of the deaf
Authors: Bush Marcia A.
Published: October 2005

Fundamental-frequency (F0) and formant-frequency data were collected for groups of deaf and normal-hearing boys and girls in order to: (1) examine the relationship between the vowel-to-vowel variations in F0 produced by deaf speakers and their proficiency at vowel articulation; and (2) explore mechanisms which might account for the exaggerated vowel-related variations in F0 produced by many deaf speakers. For the most part, greater F0 variability was observed for deaf speakers who produced a relatively wide range of vowel sounds than for speakers whose articulatory capabilities were more limited. Exaggerated vowel-to-vowel variations in F0 were produced by deaf speakers whose mean F0 was somewhat higher than normal and who were capable of articulatory configurations appropriate to high vowels. Smaller vowel-to-vowel variations in F0 were produced by deaf speakers whose mean F0 was comparable to normal and by speakers whose articulatory skills, particularly with respect to the production of high vowels, were poor. These data will be interpreted in terms of a mechanism proposed by Honda et al. [J. Acoust. Soc. Am. Suppl. 1 69, S67 (1981)] to account for interactions between vowel articulation and F0 observed for normal-hearing speakers, together with considerations of the non-linear stress-strain characteristics of vocal-fold tissue. [Work performed at the Massachusetts Institute of Technology.]
Short-latency labial afferent-to-lingual efferent intended responses: Potential contributions to the spatial-temporal coordination of speech movements
Authors: Cole Kelly J. , Abbs James H.
Published: October 2005

Kinesthetic stimuli were applied to the oral angle using a mechanical stimulus generator. Upon sensation of the stimulus subjects were instructed to produce a ‘rapid and forceful’ elevation of the tongue as in the gesture associated with a [d]. EMG responses were obtained from hooked-wire electrodes in the superior longitudinal muscle. Minimal response latencies, free from contamination by reflexes or stimulus overanticipation, ranged from 55–65 ms for all subjects. These data will be discussed in relation to (1) reports in the motor neurophysiology literature suggesting that the timing control of overlapping speech movements may permit interarticulator afferent-to-efferent triggering latencies of up to 75 ms, and (2) a recent model of speech motor control suggesting that speech coordination is achieved via open-loop, feedforward processes operating among the multiple speech structures. [Supported in part by NINCDS Program Project Grant NSq3274.]
Resonances of rectangular resonators
Authors: Bennett P. A. , Kino G. S.
Published: October 2005

We have used variational methods based on the work of Holland and Eernisse to predict the resonant frequencies of rectangular resonators for use in acoustic transducer arrays. We have predicted both the open and short circuited resonances and have compared the theoretical results obtained with a large number of experiments carried out on such resonators. When experimentally measured values of the parameters of PZT ceramics are used, the theoretical and experimental results for a wide range of configuration ratios are in excellent agreement, both for the lowest and higher order modes.
Prediction of sound scattering from a single manganese nodule
Authors: Magnuson Allen H. , Sundkvist Karl , Ma Yushieh
Published: October 2005

Sound scattering computations for single manganese nodules have been performed as part of a larger research project on remote acoustic sensing for nodule deposits in the deep ocean. Following Faran [J. Acoust. Soc. Am. 23, 405–418 (1951)] the nodule is modeled as an elastic sphere. The results of the analysis of the scattered wave field are expressed as spherical harmonic expansions. Values of wet density, compressional and shear wave speeds needed in the model were measured experimentally for nodule material. The results of the experimental investigation and computations of the scattered wave field are presented. The important frequency range around ka = 1, where k = ω/c = wavenumber and a = module radius is examined in detail. Plots of total scattering cross sections and backscatter cross sections are presented as functions of frequency. Farfield pressure amplitudes are presented as polar plots for various frequencies. The effect of nodule shear wave speed (shear rigidity) is shown to be important. Finally the applicability of the results to the deep ocean sounding problem (nodule prospecting) is explained.
Acoustic reflectivity from manganese nodule deposits
Authors: Magnuson Allen H. , Sundkvist Karl , Ma Yushieh
Published: October 2005

The presence of manganese nodule deposits on the deep ocean floor can be inferred from measurements of bottom reflectivity over a frequency range of about ka = 0.2 to 5 (where k = ω/c is the wavenumber and a is the mean nodule radius). Over this frequency range the bottom filter characteristic can be estimated from theory. Mean nodule size and amount of nodules can be computed by “inverting” bottom filter data obtained from normal incidence sounding. The inversion consists of curve-fitting the bottom reflectivity data to the theoretical model and computing mean nodule size and abundance (areal weight density) by using a least-squares error approximation. The paper consists of a development of the bottom filter model based on the scattering theory of L. Foldy [Phys. Rev. 67, 107–119 (1945)] and V. Twersky [J. Acoust. Soc. Am. 29, 209–225 (1957)]. Results of an earlier investigation of scattering from a single nodule are used in the computation. First-order scattering results using first-order Foldy-Lax closure are presented. Extensions to higher orders of scattering, self-consistent scattering and application of the quasi-crystalline assumption are discussed.
Comparisons of measured volume backscattering strengths with predictions based on midwater trawls
Authors: Hall Marshall
Published: October 2005

Volume backscattering strengths have been measured close in space and time to midwater trawls in which small deep-sea fishes were caught. The acoustic experimental method was to deploy both an omnidirectional and a directional hydrophone and to detonate small explosive charges. The experiments were all conducted at nighttime, and were repeated both inside and outside a warm-core eddy. The trawling net, which had a cross-sectional area of 8 m2, was towed at speeds of 2 to 3 kn and at depths between 30 and 360 m. The results have been analyzed at frequencies from 2.5 to 20 kHz, although the net did not capture any fish large enough to resonate at frequencies below 4 kHz. Trawls at some depths yielded few fish, and the scattering strengths at these depths increased at around 12 dB/oct. This scattering may have been due to zooplankton that were too small to be retained by the mesh. At depths where large numbers of fish were caught, there was reasonable agreement between the measured and predicted scattering strengths at frequencies greater than 5 kHz.
Sound scattered by a sinusoidally shaped surface: Comparison between experiment, finite wedge impulse solution and the Helmholtz-Kirchhoff method
Authors: Kinney W. A. , Clay C. S.
Published: October 2005

Previously [J. Acoust. Soc. Am. Suppl. 1, 68, S1 (1980)], the authors compared the exact wedge diffraction time-separable impulse solution [M. A. Biot and I. Tolstoy, J. Acoust. Soc. Am. 29, 381–391 (1957); A.D. Pierce, Acoustics, 489–490 (1981)] with a related solution involving the Helmholtz-Kirchhoff approximation [A. W. Trorey, Geophys. 35, 762–784 (1970)]. A comparison is provided here between scattered intensity values measured in a water-tank experiment [G. A. Sandness, Ph.D. thesis, Univ. of Wisconsin, Madison (1973)] and values predicted using both the Helmholtz-Kirchhoff solution and the frequency transform of an asymptotic approximation to the exact solution. In the experiment, a wave generator created a surface with a spatial wavelength of 8.8 cm and a peak-to-peak amplitude of 0.61 cm. A 205.6-kHz source (kσ = 1.9) and a receiver were located 50 cm below the surface. In the prediction using the transform, the surface was approximated by joining finite wedges edge to edge. Field values were then obtained by superposition. Agreement between these values and the experimental values is good in general. Agreement between the experimental values and those predicted using the Helmholtz-Kirchhoff solution is best near the specular direction. [Work supported by NORDA.]
Responses of bowhead whales (Balaena mysticetus) to activities related to offshore oil and gas exploration
Authors: Fraker Mark A.
Published: October 2005

The presence and behavior of bowhead whales near offshore oil and gas exploration activities in the eastern Beaufort Sea were studied during August 1980. Numerous bowheads were within 5 km of an artificial island construction site where a large dredge, a barge camp, and several boats were operating. In a different situation, the physical presence of a 16.1-m boat had no apparent effect on the behavior of bowheads at a distance of 3.7 km. Subtle changes in behavior were noted when the vessel's engines were idling with propellers disengaged. Bowheads within 1 km of vessels responded by spending briefer periods at the surface, by respiring fewer times per surfacing, and by moving away from the disturbance. Surfacing and breathing patterns returned to normal following the disturbance, while interanimal distances remained greater. Whales 13 km from an underwater seismic exploration operation did not behave differently from animals in the same area on days preceding and following the seismic work. Additional data from 1981 will also be presented. (See a companion paper on underwater noise near the above industry activities by C. R. Greene, Abstract MMI0, this session.) [Work supported by the Bureau Land Management.]
Attraction of gray whales, Eschrichtius robustus, to underwater outboard engine noise in Laguna San Ignacio, Baja California Sur, Mexico
Authors: Dahlheim Marilyn E. , Schempp James D. , Swartz Steven L. , Jones Mary Lou
Published: October 2005

Investigations on gray whales (Eschrichtius robustus) in Laguna San Ignacio have previously documented “curious” or “friendly” whale behavior towards vessels. This behavior was encountered during acoustical studies conducted in March 1981 in this lagoon. The initial response appears' triggered by the underwater sound generated from outboard engines. Whales actively seek out the sound source and physically contact slow (2–4 kts) moving small vessels (inflatable Avons, Zodiacs, wooden and aluminum skiffs). Engines kept in idle (running but out of gear) maintained these whales in close proximity for periods up to 3 hours. Some whales terminated this activity when the engine was shut off. These behaviors around vessels were video taped. Sound profiles on engine noise and ambient noise levels were collected and analyzed. This “curious” behavior is prevalent only in areas where whales are repeatedly exposed to small vessel activity. This unique behavior has occurred for the past four years in Laguna San Ignacio, and has only been recently described for Guerrero Negro Lagoon. Instances of similar behavior from other species of cetaceans will be discussed.
Underwater explosion damage risk criteria for fish, birds, and mammals
Authors: Yelverton John T. , Richmond Donald R.
Published: October 2005

In 1969 an underwater test facility was constructed specifically to study the biological effects produced by underwater blast. Investigations were conducted to determine the ranges from explosive charges, up to 3.6 kg, that were safe, damaging, or lethal to selected species of fish, birds, and mammals. It was established that the impulse (integral pdt) in the underwater blast wave was the parameter that governed biological damage and not peak pressure or energy. There was good correlation between the impulse and body weight in fish that ranged from 12 pKa⋅ms for 0.02-g guppy fry to 341 kPa⋅ms for 744-g carp. The blast response of fish with ducted swim bladders was the same as fish having nonducted swim bladders. Mallard ducks were selected as a model to represent birds on and beneath the water surface. Impulse levels that were safe, injurious, or lethal to birds were determined and presented as a function of range and charge weight. The tolerance of six mammalian species, that ranged in body weight from 0.2–45 kg, was investigated. A tentative interspecies extrapolation, relating impulse to body weight, was illustrated as a method that may be pursued to predict the response of large marine mammals to underwater blast. A safe-impulse criterion of 14 pKa⋅ms for personnel was evaluated by an unprotected swimmer in a variety of charge-depth configurations. [Work supported by Defense Nuclear Agency.]
Behavioral response of northern elephant seals and California sea lions on San Nicolas Island, California, to loud impulse noise
Authors: Stewart Brent S.
Published: October 2005

Breeding northern elephant seals (Mirounga angustirostris) and California sea lions (Zalophus californianus) on San Nicolas Island, California, were exposed to loud impulse noise created by a carbide pest control cannon. Distance of seals from the sound source varied from 5–50 m. Sound pressure levels varied from 145.5 dB(A) re 20 μPa and 146.9 dB(flat) re 20 μPa 5 m from the cannon to 115.6 dB(A) and 125.7 dB(flat) 50 m from the cannon. The intensity and duration of behavioral responses of each species to sonic stimuli varied by sex, age, and season. Responses to visual stimuli (humans) also varied seasonally and differed from responses to sonic stimuli. Habitat use, population growth, and pup survival of both species appeared unaffected by periodic exposure to carbide cannon impulse noise during the 1981 breeding seasons.
Underwater noise from oil industry activities in the Beaufort Sea
Authors: Greene Charles R.
Published: October 2005

Noises from dredges building artificial islands, a drillship, tugs, supply vessels, helicopters, and airplanes operating in the Canadian Beaufort Sea were recorded during the summers of 1980 and 1981. Numerous bowhead whales were observed and their behavior studied in the general vicinity of these noises. The signatures of both the industrial and whale noises have been analyzed and will be presented. (See a companion paper on whale behavior in the presence of industrial noises by M. Fraker, Abstract MM2, this session.) [Work supported by Bureau of Land Management.]
The acoustic environment of humpback whales in Glacier Bay and Fredrick Sound, Alaska
Authors: Malme Charles I. , Miles Paul R. , McElroy Paul T.
Published: October 2005

The number of humpback whales frequenting Glacier Bay has been decreasing in recent years while the number of whales in the Fredrick Sound and Stevens Passage area has been increasing. A study was made to determine the acoustic characteristics of both areas and measure the influence of man-made noise sources on ambient levels. ‘Transmission loss (TL) in selected regions of both areas was measured and ambient noise spectra obtained. The TL characteristics for a shallow source and receiver were observed to have a 20 log (range) dependence below 1 kHz in both areas. In Glacier Bay a shallow surface duct was observed which changed the TL to approximately 10 log (range) dependence above 1 kHz. Low ambient noise levels were observed in the absence of boat and ship traffic. Thus the sound from louder vessels dominated the ambient out to a range of up to six miles in some measurements. A significant low-frequency noise contribution, believed to be due to glacier motion, was observed at some locations in Glacier Bay. [Work supported by NOAA, NMFS and National Park Service.]