bluuebunny/crossref_metadata_2025 huggingface dataset:
Cloud cavitation
Authors: Brennen Christopher
Published: October 2013

In many cavitating liquid flows, when the number and concentration of the bubbles exceeds some critical level, the flow becomes unsteady and large clouds of cavitating bubbles are periodically formed and then collapse when convected into regions of higher pressure. This phenomenon is known as cloud cavitation and when it occurs it is almost always associated with a substantial increase in the cavitation noise and the potential for material damage associated with the cavitation. These increases represent serious problems in devices as disparate as marine propellers, cavitating pumps, and artificial heart valves. This lecture will present examples of the phenomenon and review recent advances in our understanding of the dynamics and acoustics of cloud cavitation. Both analyses of these complex multiphase flows and experimental observations will be used to identify the key features of the phenomenon and the parameters that influence it. [Work supported by the U.S. Office of Naval Research.]
Sound channeling through bubbly streams
Authors: Nikolovska Aneta
Published: October 2013

The presence of even small amount of bubbles can have a strong effect on the transmission and reduction of the sound waves through the medium in which they occur. The study presented here examines experimentally and numerically the propagation of acoustic energy in the vicinity of streams of discrete air bubbles. The acoustic energy was created naturally during the detachment of bubbles at the bottom of the stream. Previous work [A. Nikolovska, J. Acoust. Soc. Am. 115, 2473 (2004)] has reported that the root-mean-squared pressure distribution is highly anisotropic in the bubbles vicinity. A new experimental technique has been developed to obtain time frames of the instantaneous acoustic pressure field using two hydrophones. This technique allowed coordinated measurement of the acoustic energy distribution in the near and far field. The results show that the phase speed in the direction of the bubble stream has values considerably lower than the speed of sound in pure water. Different bubble stream configurations were investigated and it was found that this speed of propagation reduces and the quality factor of the sound pulses increases as the air volume fraction in the bubble streams is increased. [Work supported by RCOM.]
The N number, a speech privacy metric for rating walls, revisited
Authors: Godfrey Richard D. , Alter Harry , Berdan Clark
Published: October 2013

In 1962, Cavanaugh, et al., published the results of research which lead to a single number rating system for speech privacy of walls referred to as the N number [‘‘Speech Privacy in Buildings,’’ J. Acoust. Soc. Am. 34, 475–492 (1962)]. The N number is derived from measured one-third octave band transmission loss data weighted using factors signifying the relative contribution to the articulation index. When the N number is summed with factors for source room floor area, source room speech use, measured adjacent room background noise rating, and the privacy requirement, the N number correlated subjective reactions observed in case studies better than average wall transmission loss alone. Owens Corning, the sponsor of this research, published the N number along with sound transmission class (STC) for several years. With the emergence of regulation of speech privacy in health care facilities, the Health Insurance Portability and Accountability Act (HIPAA), it seemed reasonable to revisit the N number. This paper will review the N number methodology and compare some building partition STCs and N numbers, with special attention on the impact of cavity insulation.
Practical design and assessment of architectural speech privacy for closed rooms
Authors: Gover Bradford N. , Bradley John S.
Published: October 2013

Practical procedures have been developed for predicting levels of speech privacy associated with closed meeting rooms. The procedures can be used to specify construction designs for rooms intended to provide desired levels of speech privacy. They can also be used for measurement, assessment, and rating of existing rooms. The new approach relates the predicted or measured sound insulation provided by the wall construction directly to the probability that speech will be audible or intelligible to bystanders outside a room. The audibility or intelligibility of speech depends on the relative levels of speech and background noise at the listeners position and can therefore be determined from the speech level inside the room, the sound insulation, and the noise level at the listening position. However, speech and noise levels vary from moment to moment. The measured statistics of these variations can be used to predict the probability that speech will be audible or intelligible outside the room. Wall constructions having higher sound insulation will result in lower probabilities of speech being overheard, and therefore correspond to higher degrees of speech privacy.
Measurements of speech privacy in healthcare
Authors: Roy Kenneth P. , Good Kenneth W.
Published: October 2013

Over the last two years a series of speech privacy measurements were conducted in two healthcare facilities including a hospital, a clinic, and a medical office building. Although an ASTM field measurement method (E-1130) currently exists for open plan spaces that can be applied to healthcare applications, such a method is not currently specified for closed plan spaces. At this time, our best option is to apply the process designated in ASTM E-1130 with the additional provisions of E-336 for room-to-room NR measurement. Test results will be presented from these evaluations, and these will be discussed relative to the research conducted at the National Research Council of Canada which has taken a statistical approach to resolving one of the primary issues—in-room speech levels.
Strategy for vocalization taken by FM bats during group flight measured by a wireless microphone system
Authors: Riquimaroux Hiroshi , Osawa Yoshiki , Watanabe Yoshiaki
Published: October 2013

The purpose of this study was to examine characteristics of vocalization emitted by an FM bat, Japanese pipistrelle bats (Pipistrellus abramus), during their group flight. We used a wireless microphone system, Telemike, to record vocalization of five bats while they were flying in a chamber with a companion (a paired flight). Echolocation pulses and returning echoes were measured by the Telemike (0.6g; including a battery) placed at the bats head. Simultaneously, a pair of high-speed video cameras were used to reconstruct their flight trajectories. The Telemike recorded not only their own pulses and echoes but also those of the companion bat. Overlapping of their own echolocation signals with those of the companion bat were analyzed. For one out of two bats, overlapping was always much lower than chance level on average. On the other hand, overlapping was around chance level for the other one. Their strategy appeared that one bat reduced the overlapping while the other did not. Communication calls were also recorded between two individuals during flight, which were never recorded when the bats flew alone. [The research supported by a grant to RCAST at Doshisha Univ. from MEXT and by the Innovative Cluster Creation Project promoted by MEXT]
Modeling and analysis of the backscatter of dolphin echolocation clicks from elastic targets
Authors: Muller Mark W. , Allen John S. , Au Whitlow W. L. , Nachtigall Paul E.
Published: October 2013

The clicks from an Atlantic bottlenose dolphin were obtained in a controlled experiment at the Marine Mammal Research Program (Kaneohe Bay, HI). A previously described phantom echo experiment using solid elastic spherical targets provides the foundation for an investigation of the specific scattering components used in a dolphin’s target identification and classification methods. A model of the scattering interaction of incident dolphin echolocation clicks and elastic targets is outlined. The frequency spectra from the echolocation clicks are combined with the resonance-scattering representations of the scattered pressure fields to yield filter-type integrals that can be viewed as filtering the form function of the scatterer through the spectral window of the incident echolocation clicks. This analysis is carried out in the time and frequency domains and also represented in time-frequency distributions (Wigner-Ville, RID). An advantage of this analysis is that it can be carried out for any arbitrary echolocation click incident on targets of any general shape and composition. The results are compared and discussed with respect to experimentally obtained backscattered signals.
A new multiple angle scattering apparatus for fish and zooplankton studies
Authors: Roberts Paul L. D. , Jaffe Jules S.
Published: October 2013

Recent computer studies have indicated that a substantial improvement in classifying zooplankton and sizing fish bladders could be obtained by measuring sound scatter at a multiplicity of angles. In order to investigate the application of this principle to sound scattering from live animals, we have developed a new multiple angle scattering apparatus. The system consists of a linear array of high-frequency, broadband transducers that are aligned so that all beams intersect at roughly the same location. Complementing the acoustic sensors, the system employs two low cost cameras focused on the volume insonified by the array. The camera images are used to estimate the size and orientation of the scatterer during insonification. Preliminary results show dramatic differences in scatter recorded at each angle. These data demonstrate that recording multiple angle scatter can yield novel information about the animal being insonified, which may be used to improve estimates of its size, orientation, and taxa.
Early stages of audiovisual speech processing—a magnetoencephalography study
Authors: Hertrich Ingo , Ackermann Hermann , Mathiak Klaus , Lutzenberger Werner
Published: October 2013

Speech is a multimodal process integrating auditory and visual information. It is still unsettled at which stage of processing visual and auditory data structures merge into a common percept. This study investigates the time domain of auditory M50 and M100 fields in response to audiovisual speech (whole-head MEG, 25 subjects). As in the original video recordings (/pa/ and /ta/), the visual articulatory cues preceded the acoustic signal (synthetic syllable) by ca. 150 ms. Visual nonspeech, acoustic nonspeech, visual-only, and acoustic-only stimuli served as control conditions. In accordance with previous studies, the M50 was consistently attenuated by visual motion cues, and a similar visual ‘‘negativation’’ effect could be observed even when no acoustic signal was played. As concerns the M100 field, visual nonspeech stimuli had an attenuating effect (only in the presence of an acoustic signal) whereas visual speech gave rise to hypoadditive M100 enhancement. Application of a six-dipole model showed a categorical-like visual /p/ versus /t/ effect. Since the source of this effect was located within insular cortex rather than the auditory system, we may assume that at the time of M100 the visual phonetic information has not yet been integrated into a common auditory/phonetic representation.
Role of the Richardson extrapolation in the evaluation of acoustic data: Theory
Authors: Zuckerwar Allan J.
Published: October 2013

In many acoustical applications the method of least squares is a popular method for fitting experimental data to known physical laws or empirical functions. There are occasions when the method falls short of attaining the goals of the experimenter; for example, when estimating the value of a dependent variable beyond the range of the data (sound speed at zero frequency), fitting to a physical law described by an infinite series (acoustical virial coefficients), or fitting to a semi-empirical relationship when the governing physical law is unknown (acoustic ground impedance). Following a description of the Richardson extrapolation and the methodology for its implementation, it will be shown to resolve many of the shortcomings of a least squares analysis in the evaluation of acoustic data.
Role of the Richardson extrapolation in the evaluation of acoustic data: Applications
Authors: Zuckerwar Allan J.
Published: October 2013

Three acoustical applications of the Richardson extrapolation procedure are described, where in each case it is not possible to make a measurement at the zero value of the independent variable: (1) the vibrational relaxation time of nitrogen in the limit to zero humidity; (2) the speed of sound of methane in the limit to zero pressure (and, subsequently, its second and third acoustical virial coefficients); (3) the acoustic impedance of a grass covered field in the limit to zero frequency. In example (1), a linear regression extrapolated to zero humidity yields a physically untenable value of the reciprocal relaxation time. In example (2), in which the number of terms in the governing physical law is infinite, the results of a least-squares best-fit depends on the selected number of terms in the representative polynomial (truncation error). In example (3) the governing physical law is unknown, but semi-empirical models have a low-frequency limit that precludes the prediction of the impedance of the ground in the limit to zero frequency. The Richardson extrapolation procedure is shown to resolve these difficulties.
Fluctuation-based processing meets Hilbert transform
Authors: Wagstaff Ronald A.
Published: October 2013

Fluctuation-based processing (FBP) exploits fluctuations in amplitude and phase to achieve signal processing gains. Three consecutive fast Fourier transforms (FFTs) are required to obtain an exploitable FBP phase acceleration parameter. In addition, at least three values of this parameter are required to identify signal presence and/or to achieve the full potential of FBP. An example of interest is an acoustic probe on an unmanned air vehicle (UAV) flying among the atmosphere boundary layer, where the turbulence noise persists a significant fraction of time. In such a case, the FFT time periods have a high level of confidence of being contaminated by turbulent flow noise. Furthermore, the average of several FFTs will have a much higher level of confidence of being contaminated. Contaminated results generally have no value for identifying signal presence. One solution for this problem is a Hilbert transform, which provides temporal resolution in phase and amplitude at the sample rate, e.g., 0.001s. With such high temporal resolution, small time segments of relatively uncontaminated phase and amplitude can be automatically identified by the FBP algorithms and successfully exploited for gain. This will be demonstrated with measured air-borne acoustic sensor data. [Work supported by ARDEC.]
Eye array dereverberation by corner placement
Authors: Alghassi Hedayat , Tafazoli Shahram , Lawrence Peter
Published: October 2013

A new signal processing algorithm accompanied with a novel array structure for sound source localization (SSL) in three-dimensional spaces was presented [Hedayat Alghassi et al., J. Acoust. Soc. Am. 120(5) (2006)]. This methodology has some analogy to the eye. The microphone array’s proper placement is particularly important in enclosed areas, where reverberation is the dominant problem. It will be demonstrated that by placing the eye array’s symmetry axis along the boresight axis of an upper orthogonal trihedral corner in an enclosed area, the adverse effect of early reverberation can be substantially reduced. This enhancement is the consequence of both the retroreflection property of the orthogonal trihedral corners plus the eye array’s insensitivity to back reflections. There is a pseudo-coincidence between the estimation cells and the source direction in the eye array SSL method. Therefore, the majority of the early reflections from the trihedral corner strike the estimation cells in the direction opposite to the sound source, where the sensitivity is lowest. This approach not only reduces the adverse effect of reverberation on the SSL accuracy, but also creates an approximately flat error for all source directions. Experiments confirmed that this method achieves a reasonable accuracy improvement.
Geoacoustic inversion using combustive sound source signals
Authors: Potty Gopu R. , Miller James H. , Lazauski Colin J. , Wilson Preston S. , Lynch James F. , Newhall Arthur
Published: October 2013

In the summer of 2006, the combustive sound source (CSS) was deployed off the coast of New Jersey during the Shallow Water 2006 experiment (SW-06). CSS generates an oscillating bubble through the combustion of a fuel/oxidizer mixture, which in turn yields a low frequency acoustic pulse [Wilson, Ellzey, and Muir, IEEE J. Ocean. Eng. 20 (1995)]. The depth of these shots was 26 m in water depths of the order of 100 m. Source levels were monitored using a hydrophone placed close to the source. CSS data collected downrange on single hydrophone receiving units (SHRU) are presented. Five SHRUs were deployed by Woods Hole Oceanographic Institution (WHOI) in water depths ranging from 65 to 110 m. The CSS data collected indicate modal dispersion and are used for geoacoustic inversions. These inversions are based on matching the observed and modeled group speed dispersions including Airy phase. Historic sediment data from the location are utilized to constrain the inversions. [Work supported by the Office of Naval Research.]
Ocean acoustic sensitivity to range-dependent environmental variability
Authors: Dosso Stan E. , Morley Michael G. , McCammon Diana F. , Giles Peter M. , Brooke Gary H. , Pecknold Sean , Hines Paul C.
Published: October 2013

This paper considers the sensitivity of ocean acoustic propagation data required for sonar performance prediction to range-dependent variability in physical parameters of the ocean environment. In general, the effect on acoustic fields of perturbations to environmental parameters can consist of both a variation in the field at a point and a spatial shift of the field structure. Accounting for the field shift (via a correlation-based two-dimensional search) can provide a more meaningful measure of sensitivity for many applications. The sensitivity of acoustic fields to the state of knowledge of the bathymetry and of range-dependent variability in seabed geoacoustic parameters is examined both with and without field-shift compensation.
Bayesian full-wavefield reflection coefficient inversion and uncertainty estimation
Authors: Dettmer Jan , Dosso Stan E. , Holland Charles W.
Published: October 2013

This paper presents a Bayesian inversion technique to recover seabed geoacoustic properties of multi-layered media from measured broadband reflection-loss data taking full-wavefield effects into account. Seismo-acoustic traces are time windowed into packets with reflection effects of different sets of layers to increasing depth. Each packet is processed to yield reflection coefficients as a function of angle and frequency. The reflection coefficient data are inverted using a full-wavefield forward model. The posterior probability density is sampled with a Gibbs sampler that steps through the packages, using the results for one package as prior knowledge to constrain subsequent inversions. Prior knowledge about the number of layers and their thicknesses is obtained through a separate Bayesian inversion of picked reflection travel times. The posterior probability density for the final package is considered the full solution to the inverse problem and is interpreted in terms of parameter estimates, marginal probability distributions, credibility intervals, and parameter correlations.
High drive and duty cycle characterization of single crystal transducers
Authors: Robinson Harold , Janus Robert , Powers James , Baird P. David
Published: October 2013

Previous device demonstrations have clearly illustrated how the larger strain energy density and electromechanical coupling factors of single crystal could be used to increase both the source level and bandwidth of Naval sonar projectors. This paper will report on two experiments that conclusively demonstrate that single crystal transducers can withstand high drive levels, elevated duty cycles and extended lifetimes without a significant degradation of performance. In the first experiment, a twelve-element array of PMN-PT tonpilz transducers was driven at its resonance frequency to achieve an acoustic intensity of 5 W/sq. cm. Over a range of duty cycles up to 40% and operating times of up to 30 minutes, the impedance and acoustic output of this array remained completely stable once equilibrium had been reached. In a second experiment, a single crystal cylinder transducer was driven at its resonance frequency for ten minutes at duty cycles ranging from 10% to nearly CW. A temperature rise of only 10C over the duration of the test at the highest duty cycles was measured, with only a 20% increase in admittance and no change in tuned power factor. Both transducers returned to their original state following these tests. [This work is sponsored by ONR.]
A theory of low frequency parametric arrays in shallow water
Authors: Waxler Roger , Muir Thomas G.
Published: October 2013

Consider a highly directional transducer radiating horizontally in shallow water at two distinct frequencies. The difference frequency beam created by the nonlinear response of the medium is studied. In the far field, the difference frequency beam may be expressed as the product of a horizontal directivity function with a pressure field depending only on depth and range. The horizontal directivity function is identical to the directivity obtained by restricting the classical theory of parametric arrays in free space to two spatial dimensions. The range and depth dependence, however, is that which would be produced by the original transducer radiating at the difference frequency alone, times a small constant.
The influence of angle of incidence at a forest edge on acoustic propagation
Authors: Swearingen Michelle E. , White Michael J. , Guertin Patrick , Mifflin Jeffery , Albert Donald G. , Decato Stephen , Tunick Arnold , Onder Timothy
Published: October 2013

Acoustic propagation through a forest edge has implications for noise mitigation and acoustic detection systems. While the acoustic significance of this unique environment has been noted in the past, it has not been studied in detail. Acoustic signals that have propagated through a forest edge yield complicated pressure time histories for receivers both within and outside the forest. A recent field experiment was designed to measure acoustic dispersion and attenuation spectra in three distinct regions: open field, forest edge, and deep forest. Ground impedance, meteorological, and biomass structure data were also obtained. This presentation will investigate received signals in the open, edge, and just inside the forest as a function of the angle of incidence between the direct propagation path and the forest edge.
Infrasound propagation in unstable atmospheric layer
Authors: Naugolnykh Konstantin , Rybak Samuil
Published: October 2013

Cooling of air in upward convection flow makes water vapor supersaturated. This is a nonequilibrium state of fluid where effect of instability can be developed in the process of infrasound propagation (Nemtsov, 1989; Netreba, 1996). Atmospheric convection flow has a helical character, which introduces an additional source of instability (Moiseev et al., 2000). The basic equation which takes into account both effects is obtained in the present paper on the basis of general consideration of the relaxation process of unstable medium. Solutions of this equation indicate the effect of infrasound wave amplification and its nonlinear evolution. Corresponding analyses of them make it possible to clarify the principally important aspects of cyclone infrasound precursors.
One view of the Rudnick-Putterman UCLA-acoustics dynasties
Authors: Garrett Steven
Published: October 2013

During the second half of the 20th Century, the research group headed by Isadore Rudnick augmented then continued to this day by Seth Putterman, brought the formalism and techniques of classical acoustics and phenomenological physics to problems in the quantum mechanics of condensed matter systems. While doing so, Izzy advised 32 Ph.D. students that graduated between 1951 and 1986, half of which went on to academic careers of their own (excluding two of his sons who are also academic scientists), making the UCLA-acoustics family tree extraordinarily dense and complex. Although Putterman’s academic roots are traced all the way back to Stefan, Boltzmann, Ehrenfest, and Uhlenbeck, it appears that Rudnick’s inspiration was divine in its origin. Traveling forward from my time as a Rudnick-Putterman graduate student in the mid-1970s, several clusters of my academic siblings (fellow graduate students and post-docs) can be identified that exerted a strong influence on acoustics research and education at the Naval Postgraduate School and Penn State, many of whom were influenced by the Swift-Wheatley-Migliori (Thermoacoustics) Group at Los Alamos National Laboratory.
Genealogy of the National Center for Physical Acoustics
Authors: Bass Henry E. , Sabatier James M.
Published: October 2013

NCPA traces its roots to the Physical Acoustics Research Group which grew from the Department of Physics and Astronomy. The current Department of Physics and Astronomy acoustics effort was initiated with Prof. F. Douglas Shields who received his Ph.D. at Vanderbilt University under the direction of Prof. Robert Lageman. Professor Shields came to the University of Mississippi in 1959. He directed the dissertation of ten Ph.D. students and seven Masters students. In 1964, Prof. Shields was joined in the department by Prof. Roy Arnold who studied the ultrasonic properties of solids. Professor Arnold directed the dissertation of two Ph.D. students and six Masters students. In 1970, Prof. Randall Peters and Prof. Henry Bass joined the faculty; Bass doing acoustics in gases with a Ph.D. from Oklahoma State under Tom Winter and Peters doing solid state acoustics. The following year, Ron Carter joined the group doing solid state acoustics. Professor Bass directed the dissertation of nineteen Ph.D. students and eight Masters students. In 1976, Dr. Hans Bauer, a student of Prof. Kneser, joined the group for one year. Professor Larry Crum, a student of Prof. Stump at Ohio State, joined the faculty in 1978. In 1986, an act of Congress established the National Center for Physical Acoustics and over a period of two years, PARGUM was transferred to NCPA. Professor Ralph Goodman joined NCPA as Director in 1989. Dr. Robert Hickling and Prof. Mack Breazeale joined NCPA in 1988. Professor John Seiner joined NCPA in 1998. A listing of all additional faculty and scientists to join NCPA and the students directed by all will be presented.
Native English speakers and Arabic pharyngealization contrasts: Perceptual and acoustic data
Authors: Zaba Aleksandra M.
Published: October 2013

Arabic contrasts nonpharyngealized (e.g., /t/) and pharyngealized (e.g., /T/, with a secondary pharyngeal articulation) consonants. These contrasts are manifested acoustically by native Arabic speakers primarily via manipulation of F2 onset and steady-state values for adjacent vowels (vowels adjacent to pharyngealized consonants have lower F2 values than those adjacent to nonpharyngealized consonants). Additionally, consonant duration, following vowel onset and steady-state F1 and F3 values, and burst duration have also been reported in the literature as relevant cues. Because vowels adjacent to pharyngealized consonants tend to have lower F2 values, native English listeners may be able to exploit their sensitivity to English front-back vowel contrasts to detect Arabic pharyngealization contrasts. For example, the vowel in /ta:/ may be perceived by English listeners as closer to English /ae/ and the vowel in /Ta:/ may be perceived as closer to English /a/. We report the results of discrimination and vowel identification experiments in native English listeners’ ability to discriminate pharyngealization contrasts. These experiments examine the contributions of several acoustic cues, in particular those relevant to English vowel contrasts. We also report intertalker/dialect differences among Arabic speakers in the manipulation of acoustic cues to pharyngealization contrasts.
Asymmetrical costs of code-switching in Mandarin-Min bilingual speakers
Authors: Huang YiHsuan , Fon Janice
Published: October 2013

This paper aims to explore the processing cost incurred by code-switching for bilingual speakers. Twenty Mandarin-Min bilinguals performed a picture-naming task, in which hand-drawn pictures were color-coded for the two languages, and switching points were predetermined but variable. Half of the subjects acquired Min prior to Mandarin and half of them learned both simultaneously as their L1. Forty target stimuli were divided into two groups. One was the cognate group, in which the target stimuli form cognates in the two languages (e.g., Mandarin: jing3-cha2 versus Min: keng3-chhat4 police). The other was the noncognate group, in which the target stimuli do not form cognates in the two languages (e.g., [Mandarin] sha1-fa1 versus [Min] phong3-i2 sofa). Preliminary results showed that the response latencies of naming in code-switching trials were larger than nonswitching ones. Moreover, asymmetry time costs were found in different switching directions between the two languages. Naming latencies were longer when subjects switched from Mandarin to Min than when they switched from Min to Mandarin. In addition, reaction time for code-switching of noncognate words tended to be longer than that for cognate ones. Furthermore, subjects who acquired Min first reacted more rapidly than those who acquired both languages simultaneously.
Context effects in recognition of German disyllabic words and nonwords by native and non-native listeners
Authors: Felty Robert A.
Published: October 2013

Thirty-two native (L1=German) and 30 non-native (L1=English) listeners heard German CVCCVC words and nonwords mixed with noise. Of the words, half were monomorphemic and half bimorphemic. The j-factor model [Boothroyd and Nittrouer, J. Acoust. Soc. Am. 84, 101–114 (1988)] was used as a measure of lexical context effects. For both native and non-native speakers, words showed greater context effects than nonwords, though the difference was not as large for non-native speakers. Monomorphemic words also exhibited greater context effects than bimorphemic words, again with a larger effect for native speakers. For both native and non-native listeners, neighborhood density had a significant effect, although the amount of variation explained was much less for non-native listeners. This is interpreted to be a result of the smaller lexicon of the non-native listeners. Misperceptions between native and non-native speakers were also compared, with non-native speakers showing patterns predictable by phonological differences between the two languages. The j-factor results extend previous research using CVC stimuli, providing additional support for its efficacy as a measure of context effects. The j-factor results also provide a new finding, in that jword does not seem to scale linearly with word length. [Work supported by NIH/NIDCD.]
The soundscape of modernity: Architectural acoustics and the culture of listening in America, 1900–1933
Authors: Thompson Emily
Published: October 2013

The American soundscape changed dramatically during the early decades of the twentieth century as new acoustical developments transformed both what people heard and the ways that they listened. What they heard was a new kind of sound that was the product of modern technology. They listened as newly critical consumers of aural commodities. Reverberation equations, sound meters, microphones, and acoustical tiles were deployed in places as varied as Boston’s Symphony Hall, New York’s office skyscrapers, and the sound stages of Hollywood. The result was that the many different spaces that constituted modern America began to sound alike—clear, direct, efficient, and non-reverberant. While this new modern sound said little about the physical spaces in which it was produced, it has much to tell us about the culture that created it. This talk will explore the history of modern sound and modern culture in early twentieth-century America.
Experiments on perceiving the missing fundamental by using two harmonic components tone
Authors: Iitomi Yutaka , Matsuoka Takahide
Published: October 2013

There are some methods on acoustic experiments for perceiving the missing fundamental. Listening to one of two harmonic components from each ear and listening to a complex tone of two harmonic components from each ear are the two examples. The latter method may perceive the combination tones also. Computational experiments of the above-mentioned two methods were done by using AIM (Auditory Image Model). The effect of the value of the fundamental and the effect of the number of harmonic components on extraction of the missing fundamental information and the information of combination tones were investigated. Finally, the result of the latter method was compared with the result of the former method and the effect of combination tones on extraction of the missing fundamental information was investigated. As a result of investigating many data, the fundamental could be perceived easier in the latter method (tone containing the combination tones) than in the former method. Its mechanism was considered.
Clarifying reverberation for organ performance
Authors: Bethards Jack M.
Published: October 2013

In the conceptual phase of design or remodeling of a space for organ performance, the acoustical consultant will have a limited time in which to assess the potential for reverberation and to guide the designer in maximizing this potential. In a place of worship, the organ is likely to serve as an accompaniment to the choir and also as a solo performance instrument, both of which have their distinct acoustical requirements. It is important for the designer to fully understand the intended uses of the organ and the qualities that the organ builder wishes to emphasize. While attaining sufficient reverberation for organ performance is often a challenging task, too much reverberation, which can blur form, harmonic structure, rhythm articulation, and dynamic contrasts, must also be avoided. The architectural factors to be considered in this careful balance are reviewed together with examples of successful organ installations.
The behavior of a pipe organ in a very large room: An organist’s perspective of the Latter Day Saints (LDS) Conference Center organ
Authors: Longhurst John
Published: October 2013

The LDS Conference Center in Salt Lake City houses one of the largest theater-style auditoriums in the world. The hall seats 21,000 and incorporates a prominent pipe organ built by Schoenstein & Co. of San Francisco. The organ is characteristic of the American Romantic style, while employing a symphonic tonal approach with the richness and warmth of English instruments. A five-manual console controls the 7,708 pipes of its 130 ranks, which are spread across seven divisions. This presentation will focus on the rationale for its tonal design, dictated in part by the acoustics of the hall, and provide live demonstrations of its capabilities.
Applications of an ultra low-drag towed array deployed from a glider
Authors: Hursky Paul , Siderius Martin , Porter Michael B. , McDonald Vincent K. , Gillcrist Mark , Granger Brian , Jones Ryan , Bratten Aaron , Huizinga Andy , Sullivan Peter T. , Briest Susan G.
Published: October 2013

We have deployed a Webb Research Slocum glider towing a 21-meter 16-element line array in two experiments, the Makai experiment off of Kauai, and the PLUSNet experimient in Monterey Bay. A glider platform provides some unique capabilities. It is very quiet, by virtue of its buoyancy-driven propulsion, and it visits or samples most of the water column on a regular basis, following its sawtooth dive profile. We have collected data in several configurations, including a stop-and-drift mode, in which the array assumes a vertical posture, recording narrowband and broadband controlled sources and ambient noise. We will present the results of processing these datasets, and discuss their implications for surveillance, seabed mapping, and ambient noise measurements.
Focused ultrasound surgery monitoring using local harmonic motion imaging
Authors: Curiel Laura , Chopra Rajiv , Hynynen Kullervo
Published: October 2013

The present study established the feasibility of a real-time monitoring technique for focused ultrasound (FUS) lesion formation using localized harmonic motion imaging. This oscillatory motion was generated within tissues by periodically induced radiation force using a FUS transducer (oscillatory motion frequencies between 50 and 300 Hz). The harmonic motion was estimated using cross correlation of rf ultrasonic signals acquired at different instances during the motion by using a separate US diagnostic transducer excited by a pulser/receiver. The technique was evaluated on rabbit muscle under in vitro and in vivo conditions. Fourteen FUS lesions were induced in vivo inside an MR scanner to obtain simultaneous ultrasound harmonic motion tracking and MR thermometry. The calculated maximum amplitude of the induced harmonic motion before and after the lesion formation was significantly different for all the tested motion frequencies. During the FUS exposure a drop in the maximum amplitude value was observed and could be associated to a lesion formation. After the lesion formation, the harmonic motion was measured across the exposure region, and the lesion was detected as a reduction in the maximum motion amplitude value at the coagulated region. [Work supported by NIH Grant R21/R33 CA102884-01.]
Evolution of time-varying loudness during nonlinear propagation of broadband noise
Authors: Swift S. Hales , Gee Kent L.
Published: October 2013

Previous work has shown that loudness and sound quality metrics that rely exclusively on the power spectrum do not adequately represent the perceptual impact of nonlinearly propagated noise. [K.L. Gee et al., J. Acoust. Soc. Am. 121, EL1–EL7 (2007)]. This discrepancy between spectral content and perceptual quality appears to be related to the formation of acoustic shocks in the pressure waveform. Because time-varying loudness (TVL) more accurately represents temporal effects in the ear, a preliminary investigation of the response of TVL to nonlinearly propagated noise has been carried out. TVL has been calculated for a shaped broadband noise waveform as it is nonlinearly propagated using a generalized Burgers equation-based model. The same waveform is also propagated using a linear model and the TVL for the nonlinear and linear waveforms are compared and discussed. An additional comparison carried out is that of the nonlinear waveform’s TVL and the TVL for the nonlinear waveform with its Fourier phase randomized. This phase randomization preserves the nonlinear waveform’s power spectrum but eliminates the acoustic shocks in the time domain. The nonlinear waveform shows more variation in both short and long term loudness than either the linear or the phase-randomized waveform.
Global and local responses of coupled dynamic systems
Authors: Maidanik Gideon , Hughes Ronald
Published: October 2013

Responses of a master oscillator coupled to a set of satellite oscillators are evaluated. A set is designed by specifying a normalized frequency distribution. When the designed distribution is completely degenerate, the influence of the coupling is global. The coupling generates two global peaks, one on each side of an antiresonance that replaces the peak in the response of the uncoupled master oscillator. The loss factor for these global peaks matches that of the uncoupled master oscillator. As the degeneracy is gradually removed, the evaluated response gradually reveals, within the distribution bandwidth, contributions from individual satellite oscillators. The loss factors and the frequency separation of the two global peaks then become dependent upon the coupling. As the degeneracy is further removed, the local presence of the satellite oscillators assumes the dominant feature in the response whereas the presence of the two global peaks subsides. Since the designed distributions relate loss factors directly to modal overlap parameters, increases in these parameters above unity render this dominance in the response quiescent and saturated. On the other hand, continuous decreases in these parameters below unity increase the fluctuations in that dominant part of the response ad infinitum.
Intraglottal pressures relative to laryngeal airway configuration
Authors: Scherer Ronald C. , Agarwal Meena , Tennakoon Inoka , Zhai Guangnian , Li Sheng , Kucinschi Bogdan , De Witt Kenneth
Published: October 2013

This presentation summarizes results of empirical and computational studies with steady flow to indicate how normal intraglottal pressures vary as a function of (a) glottal angle, (b) radius of the glottal entrance and exit, (c) glottal obliquity, (d) inferior and superior vocal fold surface angles, and (e) false vocal fold gap. Empirically obtained intraglottal pressures differ in significant ways from earlier theoretical work and current simplified expressions. Intraglottal pressures are highly sensitive to glottal angle, entrance radius for the diverging glottis, and the exit radius for the converging glottis. Air pressures in the glottis are asymmetric when the flow is asymmetric, as they typically are in the divergent glottis. The oblique glottis produces asymmetric pressures that depend upon vocal fold angle and flow separation. Intraglottal pressures are typically lower on the side where velocities are faster. Intraglottal pressures are essentially independent of the wide range of inferior and superior vocal fold surface angles found in the human. When the ratio of the false fold gap to glottis minimal diameter is about 2, laryngeal flow resistance and intraglottal pressures reduce; flow resistance and intraglottal pressures quickly increase for gap ratios less than one. [Work supported by NIH R01DC03577.]
Determination of frequency dependence of sediment attenuation in shallow water using the combustive sound source
Authors: Knobles David P. , Wilson Preston S. , Cho Steve E.
Published: October 2013

Acoustic signals generated by the combustive sound source (CSS), an impulsive source based on hydrogen-oxygen combustion, were recorded at various source-array ranges on two L-arrays during the Shallow Water’06 experiment off the coast of New Jersey, in about 70 m of water. The bandwidth of the CSS is about 3 kHz and thus offers an opportunity to determine those geo-acoustic parameters of the seabed that are frequency dependent. One parameter that has received significant attention is the sediment attenuation due to its importance in correctly predicting transmission loss in shallow water. In principle, if one can determine the real part of the sediment sound speed and layering structure, the received acoustic data over a 3 kHz band could be used in combination with an advanced propagation model to determine the frequency dependence of the sediment attenuation. The central hypothesis of the study is that while such an inverse approach is subject to non-uniqueness, a significant number of physical measurements such as the sound speed profile in the water column, bathymetry, and sub-bottom layering that were made along the propagation paths may provide adequate constraints that allow for a unique determination of the sediment attenuation. [Work supported by ONR.]
Temporal variability of narrow-band tones in very shallow coastal waveguides
Authors: Lynch Stephen D. , D’Spain Gerald L.
Published: October 2013

During an experiment near San Clemente, CA, a source moored on the bottom just outside the surf zone (500 m offshore, approximately 9-m depth) transmitted eight tones between 70 and 700 Hz to two nearly perpendicular, 64-element bottom-lying hydrophone arrays located approximately 1.2 km downcoast and 1 km further offshore (approximately 12-m depth). The acoustic tones were transmitted for 5 min every half hour over a 22-h period. Surface wave data obtained from a depth sensor array located approximately 40 km upcoast, as well as data from a PUV sensor data deployed during the experiment, are used to compute concurrent directional surface wave spectra. Long fast Fourier transforms of the acoustic recordings reveal temporal and spatial variability of the width and shape of the received tones in temporal frequency space. Surface-wave-related mechanisms of acoustic frequency distortion are proposed and their relative significance is investigated through the comparison of the data with results from physics-based models that use the measured surface wave properties as input parameters.
Archaeoacoustics re-examined
Authors: Wright Matthew C. M.
Published: October 2013

Archaeoacoustics examines the acoustic properties of ancient artifacts, buildings and natural spaces in order to shed light on the past. In one such study by Jahn, Devereux, and Ibison [J. Acoust. Soc. Am. 99, 649–658 (1996)] it was found that a number of ancient enclosures (principally neolithic burial chambers) exhibited similar resonance frequencies. It has subsequently been suggested that their results imply that these chambers were used for chanting and were intentionally built to enhance this. A re-analysis of their data will be presented which indicates that this is unikely to be a valid conclusion. [This research was supported by an EPSRC Advanced Research Fellowship.]
An acoustic raindrop effect at Chichen Itza in Mexico
Authors: Cruz Calleja Jorge Antonio , Declercq Nico F.
Published: October 2013

One of the acoustic effects caused by the staircase of the El Castillo pyramid at Chichen Itza is the so-called raindrop effect [Declercq et al., J. Acoust. Soc. Am. 116(6), 3328–3335 (2004)]. When visitors climb the colossal staircase of Maya pyramids, their footsteps are transformed into sound having distinct frequencies similar to raindrops falling in a bucket filled with water. In situ experiments are reported followed by numerical simulations of the raindrop effect together with a physical explanation. In addition to numerical simulations, a rule of thumb formula is extracted from the calculations that enable the prediction of the acoustic raindrop frequency at any other pyramid in Mexico. If the raindrop effect is a phenomenon that was intentionally incorporated in the construction of the Maya pyramids, such as the pyramid in Chichen Itza, then it was most probably related to the rain god Chac for which there is ubiquitous archaeological evidence decorated on the pyramid itself.
The recent history of our understanding of low-mode internal tides in the ocean
Authors: Dushaw Brian D.
Published: October 2013

The past decade has seen a renaissance in the interest in oceanic internal tides and their role in mixing the abyssal ocean. One of the sparks of this renaissance was the discovery of the remarkable coherence of low-mode internal tides using an ocean acoustic tomography array deployed in the central North Pacific Ocean in 1987. The result was subsequently confirmed by satellite altimetry. This talk will review these results and related results from the 1991 Acoustic Mid-Ocean Dynamics Experiment (AMODE) in the North Atlantic and the 2001 Hawaiian Ocean Mixing Experiment (HOME) around the Hawaiian Ridge. Internal tides are generated by tidal forces hence they are a means by which the tides dissipate energy. With wavelengths of 150-km, low-mode semidiurnal internal tides appear to propagate 1000’s of kilometers across ocean basins while retaining considerable coherence.