bluuebunny/crossref_metadata_2025 huggingface dataset:
An overview of Kim Benjamin's U. S. Navy transducer developments
Authors: Howarth Thomas R.
Published: May 2014

Kim Benjamin had already enjoyed a distinguished career as an acoustician at the University of Rhode Island and Raytheon Company before joining the U.S. Navy as a civilian scientist in 1995. From 1995 to 2013, Kim focused primarily on advancing 1–3 piezocomposite materials into unique underwater acoustic devices. Among key accomplishments are the following: design of 1–3 piezocomposite-based beam steered parametric mode transducers with integral high-gain receivers; design of parametric mode sub-bottom profiler transducers; development of U. S. Navy calibration transducer standards F82 and F83; use of 1–3 piezocomposites with area shaded electroding to realize a new class of transduction which maintains a constant beamwidth over a two octave bandwidth; novel use of singly and double curved piezocomposites; design and segment demonstration of a cylindrical array module that is coupled linearly to form a towed line array with 3D spatial discrimination; design and fabrication of a 120 element conical octahedral homing array for high speed (>150 knots) applications. He also was involved in the development of thin, low frequency acoustic sources as he designed a complex set of tooling to accomplish mission objectives. This presentation will overview Kim's Navy contributions with design drawings, photographs, and experimental data.
Constant beamwidth transducers: A tribute to Kim Benjamin
Authors: Huang Dehua
Published: May 2014

Constant beamwidth transducer (CBT) is a special acoustic transducer, where acoustic beamwidth is independent of frequency, because of its Legendre polynomial normal velocity distribution on the surface of transducer spherical dome. By elegant design of Legendre polynomial normal velocity distribution profile on the transducer radiation surface dome, acoustic sidelobes can also be controlled and eliminated. To achieve Legendre polynomial normal velocity distribution, electrode area shading is one of important techniques to design a practical CBT. in this paper, the CBT designs, shading patterns, size effects, frequency band limit, build of materials, as well as Mr. Kim Benjamin critical contributions in the field toward a U. S. Navy standard CBT transducer at the Underwater Sound Reference DivNpt (USRD) will be summarized.
Outstanding work of Kim Benjamin on 1–3 composite transducers and acoustic analysis
Authors: Walsh Kenneth M.
Published: May 2014

Kim Benjamin was one of the most productive acoustic system researchers that I have known. Kim, myself, and Walter Boober developed acoustic techniques that increased the productivity of the NUWC acoustic facility by a factor of 10. Kim and I produced a number of patents related to the use of 1–3 composite transducers in naval sonars. The last effort with Kim produced a small diameter, broad band transducer that was tested successfully. Kim was a Fellow of the ASA and is greatly missed.
Where they are, where they have been, and where they are going
Authors: Cottingham James P.
Published: May 2014

The ASA Best Student Paper Awards competition began in 1997. From 1997 to 2001, one award winner in Musical Acoustics was selected at each meeting, but beginning in 2002, two awards have been given, with first and second prize winners selected. In all there have been 52 award winners in Musical Acoustics, including three who won an award twice. Some are still active in musical acoustics, but many others are now active in other areas of acoustics or in fields outside acoustics altogether. A brief overview will be presented of the history of the competition and past and current interests of those who have been the award winners. The speakers in this session include winners of the award since the last Providence meeting in 2006. Capsule updates on several award winners who are unable to participate in this session will be presented.
From musical acoustics to outdoor sound and back
Authors: Coyle Whitney L.
Published: May 2014

My musical acoustics student paper award was given in 2009 at ASA San Antonio after an NSF summer research experience at Coe College with Dr. James Cottingham. I was a junior at Murray State University in Kentucky studying the clarinet and mathematics. Though I was not the most qualified applicant, lacking the physics background necessary in this field, I had a passion for acoustics and wanted my future to go in this direction. This summer was my introduction to acoustics research and the reason I was able to continue in the field. Since, I have been attending Penn State in the Graduate Program in Acoustics and have earned my Masters in Acoustics focusing on outdoor sound propagation modeling and now, with the help of an NSF-GRFP, I have found my way back to musical acoustics—clarinet acoustics. Since the San Antonio ASA I have attended seven more ASA conferences, been the musical acoustics student council representative and am now the student council chair. I now split my time between Penn State and Marseille, France, at CNRS-LMA. This talk will detail each step along the path that retuned me to musical acoustics and give a look into my current research as well.
Categorization and lexicon in verbal descriptions of violin quality by performers
Authors: Saitis Charalampos , Fritz Claudia , Scavone Gary P.
Published: May 2014

This work aimed to explore how violin quality is conceptualized as reflected in spontaneous verbal descriptions by experienced performers collected while playing in a perceptual evaluation experiment. Participants performed a preference ranking task and justified their perceptions in a free verbalization task. Using the constant comparison analysis from grounded theory, a concept map was developed, which can be useful for future studies aimed at assessing violin qualities. A psycholinguistic analysis of the quality-descriptive lexicon used by violinists further revealed a variety of linguistic devices referring to either the sound of a violin or to the violin itself as the cognitive objects. Adjectives for the description of sound characteristics are largely borrowed from four semantic fields related to texture-temperature (smooth vs. rough), action-presence (resonant vs. muted), size-volume (deep vs. flat), and light (dark vs. bright). These semantic fields indicate what type of dimensions may explain the perception of violin timbre, contributing to the area of violin acoustics research as well as to the broader area of timbre research. Some acoustical interpretations are discussed in the context of finding correlations between measurable vibrational properties of a violin and its perceived quality.
An experience-based approach to auditory perception research
Authors: Monson Brian B.
Published: May 2014

What and how we hear is determined by our past experience. Thus attempting to quantify human experience becomes the challenge for modeling auditory perception. Based on my recent research at the Duke-NUS Graduate Medical School in Singapore, I will discuss some principles that should guide such an approach to study of auditory neuroscience and perception. One crucial principle is to account for the frequency of occurrence of stimulus patterns to which humans have been exposed over phylogeny and ontogeny (an alternative to explaining perception based solely on peripheral auditory physiology). I will discuss the implications of this research approach and include a brief report on my research progress in my new position at Brigham and Women's Hospital.
Kenneth McKechnie Eldred—A distinguished noise control engineer II
Authors: Maling George C. , Wood Eric W.
Published: May 2014

Ken's accomplishments in noise control engineering cover the spectrum from basic engineering research to recommendations for noise control in six areas: measurement of industrial noise; measurement and reduction of structural vibration in space vehicles; noise radiation from jet flow; noise reduction of jets by multiple nozzles and turbofans; vibroacoustic environmental simulation for aerospace vehicles; and community and transportation noise control. Some of these areas are discussed in consulting reports, and others in papers published in the open literature. He was a consultant at Bolt Beranek and Newman from 1973 until 1982 when he formed Ken Eldred Engineering. His publications appeared in the journal NOISE Control, several NOISE-CON and INTER-NOISE Proceedings, Noise Control Engineering Journal, and the Journal of the Acoustical Society of America. Representative samples of his accomplishments taken from the above sources will be presented.
Harvey Hubbard and the Acoustical Society of America oral histories project
Authors: Sparrow Victor
Published: May 2014

Harvey Hubbard was an amazing person who contributed substantially to both the profession of acoustics and to the Acoustical Society of America. This short talk is the story of Harvey Hubbard's ASA oral history. It was a great honor to work with Harvey on his oral history. The transcript of the interview is currently available online through the American Institute of Physics' Center for History of Physics and the Niels Bohr Library and Archives. The interviewer for that oral history will recount some of the highlights from Harvey giving that interview and from some of the superlative life experiences he recounted. Everyone is encouraged to participate in the collection of similar oral histories for the preservation of the history of acoustics and the history of the ASA.
Nonlinear surface acoustic waves on lithium niobate in microfluidic devices
Authors: Ilinskii Yurii A. , Zabolotskaya Evgenia A. , Hamilton Mark F.
Published: May 2014

Surface acoustic waves (SAW) are used frequently in microfluidic devices. Normally SAWs are generated on the surface of a piezoelectric material. Commonly used PZT is not appropriate for biomedical applications because of its high lead content, over 60% by weight. In this talk, a study of nonlinear SAW propagation in a piezoelectric substrate is presented. Model equations describing nonlinear SAW propagation in a piezoelectric crystal are derived from first principles. Elastic, piezoelectric, dielectric, and electrostrictive properties of a crystal with arbitrary symmetry are taken into account. The derived evolution equations are integrated numerically to illustrate nonlinear distortion of an initially sinusoidal wave of finite amplitude. As an example, SAW propagation along the X axis on single crystal 127.680 YX-cut lithium niobate (LiNbO3), referred to as 128-YX-LN, is considered. This LiNbO3 cut is typically used in microfluidic devices because it provides large mechanical displacements in the substrate. Analysis of the nonlinearity matrix permits quantification of the relative contributions to surface wave distortion from each physical phenomenon. [Work supported by the IR&D program at ARL:UT.]
Design of piezoelectric energy harvesting system using cantilever beam
Authors: Kim Jin-Su , Jeong Un-Chang , Lee Sun-Hoon , Jeong Jung-Min , Oh Jae-Eung
Published: May 2014

In this paper, a design for an energy harvesting device using cantilever beam will be investigated and experimental results will be presented to validate the design. The energy harvesting device in the study is 31-unimorph piezoelectric which was used to convert small amplitude mechanical vibration from a specific machine application into an electrical energy source that could be used for electronic devices with low power requirements. The primary purpose of the design is to illustrate a method to design a cantilever beam that is optimized for attached position of piezoelectric by Experiment and FEM. From the given vibration data a range of frequencies where the energy harvesting device will generate the greatest amount of energy is determined. The device is then designed specifically targeting that frequency range with sinusoidal wave about resonant frequency. And results of this study show the change trend of output voltage according to changing circuit elements. This approach is presented as part of a more general approach to designing energy harvesters for any application. Also, it will be shown how attached position of piezoelectric used for cantilever beam were chosen.
Modulation masking within and across carriers for subjects with normal and impaired hearing
Authors: Moore Brian C. , Baer Thomas
Published: May 2014

Sid Bacon was a pioneer in studies of the extent to which the detection of target amplitude modulation (AM) of a carrier is affected by additional (masker) amplitude modulation applied to the same carrier (within-channel modulation masking) or to a different carrier (across-channel modulation masking). Here, these two types of modulation masking were compared for normal-hearing and hearing-impaired subjects. The target was either 4-Hz or 16-Hz sinusoidal AM of a 4000-Hz carrier. The target AM depth was fixed. The masker AM was applied either to the same carrier or to a carrier at 3179 or 2518 Hz. The masker AM rate was 0.25, 0.5, 1, 2, or 4 times the target rate. The masker AM depth was varied adaptively to determine the value needed just to mask the target AM. Preliminary results indicate that within-channel modulation-masking patterns are similar for normal-hearing and hearing-impaired subjects, suggesting that the hypothetical modulation filters are not affected by hearing loss. However, the amount of across-channel modulation masking is lower for normal-hearing than for hearing-impaired subjects, presumably because of the reduced frequency selectivity of the latter. The increased across-channel masking for the hearing-impaired subjects may contribute to their difficulties in understanding speech in background sounds.
Role of temporal fine structure in speech recognition: From psychoacoustics to cochlear implants
Authors: Apoux Frederic , Healy Eric W.
Published: May 2014

The path from fundamental research to real-world application is often long and sinuous. This presentation will depict how psychoacoustic studies performed in Sid Bacon's laboratory have engendered our original view of the role of temporal fine structure (TFS) in speech recognition, and how this view has in turn led to the development of an extremely effective speech-processing strategy for cochlear implants. First, psychoacoustic data showing how normal-hearing listeners can detect amplitude modulation when presented with only the TFS will be described. Second, a series of experiments illustrating the “absence” of acoustic speech cues in the TFS will be briefly presented. Finally, the results of a recent study involving a dual-carrier vocoder will be described. These results suggest that TFS cues are primarily used to assist in identifying which auditory channels are dominated by the target signal so that the output of these channels can be combined at a later stage to reconstruct the internal representation of that target. They also indicate that cochlear implants implementing a speech-processing strategy based on the “dual-carrier strategy” have the potential to restore nearly perfect speech intelligibility in noise. [Work supported by NIH.]
The acoustic structure of whistles as a tool for identifying evolutionary units in dolphins
Authors: Papale Elena , Azzolin Marta , Cascao Irma , Gannier Alexandre , Lammers Marc O. , Oswald Julie N. , Perez-Gil Monica , Silva Monica , Giacoma Cristina
Published: May 2014

Acoustic signals are expressions of phenotypic diversity and their variation could provide important information on differentiation patterns within species. Due to a number of selective pressures acting on signals, the contribution of genetic drift is often complex to outline. This study aims at evaluating if an examination of the acoustic structure of communication signals can allow the identification of evolutionary units in species capable of vocal learning. We quantified and compared parameters of whistles emitted by three dolphin species (Stenella coeruleoalba, Delphinus delphis, and Tursiops truncatus) to examine the hypothesis that acoustic signals permit the recognition of differentiation between populations from the Atlantic Ocean and the Mediterranean Sea. In the three species, recordings were correctly assigned to their basin of origin with a percentage higher than 82% by DFA. Frequency parameters were the most stable within each species. Where gene flow has been shown, i.e., within Atlantic Ocean, significant differences were found principally in modulation parameters. We hypothesize that these parameters are influenced by social and behavioral factors and that similar ecological conditions led to convergent acoustic features. Results of this study suggest that is it possible to recognize evolutionary units based on acoustic data.
Construction monitoring—A lack of standardization
Authors: Rynberg Tyler
Published: May 2014

Construction noise and vibration monitoring is being required more and more frequently, especially for large infrastructure projects. Work on these civil projects often involves tunneling, piling, large-scale earthworks, and even blasting—all in close proximity to commercial or residential population centers. Aside from the human-related annoyance effects, there are effects on the environment (endangered species) and the possibility of damage to structures. Because construction monitoring for noise and vibration is a relatively young field, there is little guidance for agencies to consult; the result is a multitude of differing monitoring requirements on these projects. From project to project, the monitoring requirements differ in subtle ways that do not necessarily correspond to the true needs of different projects. This presents serious problems in terms of developing consistent protocols (allowing apples to apples comparisons) and also in instrumentation, as most instrument vendors are too inflexible to meet the range of requirements or are too expensive for the flexibility they do offer (or both). A discussion to develop more consistent standards in construction monitoring is needed.
Acoustics concepts you can demonstrate with a coffee mug
Authors: Morrison Andrew C.
Published: May 2014

The simple coffee mug can be used to illustrate many important concepts in acoustics. Adding water to the mug shows the effect of mass on the frequency of oscillation. Striking on the handle of the mug compared to striking the side of the mug shows the vibrational mode degeneracy lifting. Adding instant coffee or hot chocolate mix to a mug full of water heated in a microwave oven shows the effect of bubble density on the speed of sound. Each of these concepts are easily demonstrated and can also be used as starting points for student exploration in the laboratory.
Time and intensity with Tino
Authors: Stern Richard M.
Published: May 2014

Over a period of decades Constantine (Tino) Trahiotis has been a contemplative and creative scholar, an excellent teacher, a helpful collaborator, as well as a loyal friend. Tino, along with Bob Bilger and Erv Hafter, provided this author's introduction to the broader science of hearing beyond the particular perspective of my graduate training. At the same time, my attempts to interpret models of binaural interaction with Tino led to the review chapters on binaural modeling that the two of us jointly authored in the 1990s. Tino's demonstration of the unexpected dependence on bandwidth of the laterality of bands of noise presented with interaural temporal differences of large magnitude motivated me to think about the tradeoff between “straightness” and “centrality,” which appears to be helpful in considering the lateralization of many binaural stimuli. Finally, Tino, along with Les Bernstein, insisted on a local implementation of my models in their laboratory which became one source (along with significant others) for the binaural modeling toolbox developed by Michael Akeroyd that is presently in wide circulation. This talk will review these facets of my life with Tino, and comment on my current perspectives on related issues. [Work supported by DARPA and Cisco Research.]
The influence of pause, attack, and decay duration of the ongoing envelope on the extent of lateralization produced by interaural time differences of high-frequency stimuli
Authors: Dietz Mathias , Klein-Hennig Martin , Hohmann Volker
Published: May 2014

Klein-Hennig et al. [J. Acoust. Soc. Am. 129, 3856 (2011)] investigated the influence of the duration of specific modulation cycle segments within the ongoing envelope waveform on the sensitivity to interaural time differences (ITD). The ITD sensitivity, measured in a two alternative forced choice discrimination task, was reported to increase for increasing pause and decreasing attack segment duration. The study also revealed that “on” and decay durations have little to no influence on the threshold ITD. The current study employed a subset of nine envelope shapes from the previous study and measured the extent of lateralization produced by ongoing ITDs with an acoustic pointing task. Lateralization generally increased monotonically with ITD for the measured values of 0.2, 0.6, 1, and 2 ms. An additional condition measured combined lateralization of a 1 ms ITD and an opposing 5 dB interaural level difference. It was observed that the extent of lateralization increases with increasing pause duration or with decreasing attack duration in line with the threshold ITD data. However, the different influence of attack and decay flank on ITD sensitivity translates into significant differences in the extent of lateralization only for a subgroup of subjects.
A neural measure of interaural correlation based on variance in spike count
Authors: McAlpine David , Jones Simon , Marquardt Torsten
Published: May 2014

Interaural Correlation (IAC) is related to variance in Interaural Time Difference (ITD) and Interaural Level Difference (ILD). While normalized IAC can account for behavioral performance in discrimination tasks, so can models directly employing this variance as a cue. Attempts at identifying a neural correlate of IAC discrimination have focused on changes in mean spike count, typically at the peaks of ITD tuning curves. We propose that IAC discrimination relies on variance in spike rates on the slope of neural tuning curves (for ITD). We developed a physiologically based hemispheric-balance model of IAC, where fluctuations in the ratio of activity between left- and right-brain serve as the detection cue to a reduction in IAC from unity, a ratio that is stimulus power invariant. Adjusting model parameters, we find that two orders of magnitude less activity is required in the variance-based, compared with mean spike-rate based, model, in order to achieve the same performance. This adjustment also revealed a necessary neural time integration of 10 ms, which is comparable with physiological estimates. The model was tested by recording neural responses from the midbrain of anesthetized guinea pigs to noise stimuli of various IAC.
Talker-specific influences on phonetic category structure
Authors: Theodore Rachel M.
Published: May 2014

A major goal of research in spoken language processing has been to describe how listeners achieve stable perception given the marked variability in mapping between the acoustic signal and linguistic representation. Toward this end, the research of Joanne L. Miller and colleagues has shown that speech sound categories, like other cognitive/perceptual categories, have rich internal structure, with category membership represented in a graded fashion. Moreover, category structure robustly shifts as a function of variation in the speech signal including variation associated with phonetic context, speaking rate, and dialect. I will discuss evidence indicating that internal structure also reflects talker-specific phonetic variation. These experiments concern talker differences in voice-onset-time (VOT), an acoustic parameter that marks the voicing distinction in stop consonants. I will begin with findings from production experiments that explicate talker differences in VOT with the goal of generating predictions for how listeners might accommodate such differences. I will then present findings from perception experiments indicating that listeners comprehensively adjust the mapping between the acoustic signal and phonetic category to reflect a talker's characteristic VOT distribution. Collectively, these findings demonstrate that listeners accommodate variability in the speech stream by dynamically adjusting internal category structure in light of systematic acoustic variation.
The role of systematic variation in speech perception
Authors: Nygaard Lynne C.
Published: May 2014

A signature problem in our understanding of spoken language processing is the highly variable nature of the speech signal. The realization of linguistic form changes profoundly from utterance to utterance, individual speaker to individual speaker, and group of speakers to group of speakers. On the one hand, this high degree of variation is a problem for accounts of speech perception and spoken language comprehension. Listeners must maintain robust perceptual constancy in the face of the enormous variability in the instantiation of linguistic form. On the other hand, listeners are sensitive to the fine-grained structure of linguistic segments that signals differences among talkers and speaking styles. Variation is informative providing important cues to attributes of the individual speaker and social context. Empirical and theoretical work will be presented that attempts to reconcile the stability of speech perception with the informative nature of systematic variation. This work suggests that listeners both dynamically adapt to systematic changes in linguistic category structure and encode linguistically relevant variation in representations of spoken language. The findings suggest considerable behavioral and representational plasticity in speech perception and spoken language processing and highlight the importance of lawful variation for spoken communication.
Quantitative non-linear ultrasonic imaging of targets with high acoustic impedance contrast—Application to bone imaging
Authors: Guillermin Régine , Lasaygues Philippe , Rabau Guy
Published: May 2014

This study focuses on the ultrasonic imaging of high impedance acoustical contrast targets. The aim is to obtain information about shape, dimensions, and sound speed profile of the studied objects. One domain of application is the characterization of long bones. Quantitative information about the acoustic properties of bones tissues are of great interest for diagnosing or treatment monitoring of bone diseases. Inverse scattering problems of this kind are non-linear and various approximations can be used to linearize the scattering equations. Classical methods based on the first-order Born approximation give good results for weakly scattering targets but fail when it comes to give a quantitative information especially for high impedance contrast targets such as bones. In the inversion algorithm proposed here, Green's theorem is used to obtain a domain integral representation of the scattered field. An iterative non-linear algorithm minimizing the discrepancy between the measured and computed scattered fields is used to reconstruct the sound speed profile in the region of interest. The minimization process is performed using a conjugated-gradient method. An experimental study was performed with targets made of paraffin and with lamb bones. Images of the sound speed profile obtained by inversion of experimental data are presented and discussed in both cases.
Acoustic measurements of rock formations in oilfield boreholes
Authors: Johnson David L.
Published: May 2014

Once a borehole is drilled into a rock formation as a potential oil or gas well the environment needs to be characterized by a variety of physical measurements so that e.g. one may know at what depths the hydrocarbon, if any, is located. In this talk I will outline some techniques for measuring, in situ, the compressional and shear speeds of sound in a rock formation as a function of depth. Here the “difficult and challenging conditions” are that the measuring instrument is inside the sample (rather than the other way around), the temperatures may reach 175 °C, and the pressure in the borehole may reach as high as 1000 atmospheres.
Health based approach for regulations for vibrations from rail traffic
Authors: van den Berg Martin
Published: May 2014

Several countries adopted regulations for vibrations and a few made this even statutory. Most do however not endeavor to regulate vibrations are make weak references to—old—standards. Partly, this seems due to the perceived complexity, partly to a lack of knowledge, and partly to the feeling that vibrations are somehow less of a problem. In this paper, a procedure is described to derive limit values for rail vibrations according to WHO-rules for the use of epidemiological evidence in environmental risk assessment. Recent developments in the EU-project CARGOVIBES made it possible to get sufficient data to make this possible. Not all elements that are necessary for a stable regulatory system are obtained, but at least politicians may be supported much better in the decisions for a better protection of the population. Worrying gaps in knowledge are the influence of night exposure on health, the interaction with noise exposure and the effectiveness of measures.
Approximation of a physics-based model of surface reflection loss
Authors: Jones Adrian D. , Zinoviev Alex , Bartel David W.
Published: May 2014

A model of coherent acoustic reflection loss at the ocean surface had been prepared by the authors by combining a model of surface roughness loss with a description of surface incidence angle which accounted for the refractive effects of a uniformly stratified distribution of wind-driven bubbles. Here, surface roughness loss was based on a second-order small-slope approximation, and the surface incidence angle was obtained using a formulation for stratified media from Brekhovskikh applied to the sound speed variation resulting from the bubble distribution used by Ainslie [JASA 118, (2005)]. More recent work by the authors has shown that the analyses for each of surface roughness loss, and surface incidence angle, may be approximated adequately by relatively simple expressions, and that the complete model of surface reflection loss inclusive of the refractive effects of bubbles may be approximated in expressions suitable for hand calculations. Results from the use of this approximated model with a Gaussian-beam acoustic propagation code are compared with results obtained from the authors' more complete model for several surface ducted transmission scenarios. Both sets of results are also compared with predictions based on Monte Carlo parabolic equation (PE) transmission calculations.
Spatial diversity in application of the decomposition of the time reversal operator (DORT) method to imaging of an extended target
Authors: Li Chunxiao , Guo Mingfei , Cheng Qianliu
Published: May 2014

Taking advantage of the multipath propagation in shallow water waveguide, high resolution can be achieved with the decomposition of the time reversal operator method. In this paper, we investigate how to use the spatial diversity for imaging of an extended target. It is assumed that the target is composed of an infinite number of random, isotropic, and independent scatterers, uniformly distributed over an unknown region. The eigenvalues and eigenvectors associated with the target are first determined. We then employ the frequency characterizations of scatterers from a singular value decomposition of the time reversal operator to localize and image the target. Tank experiments are carried out for a steel cylinder in two kinds of random media: a shallow water waveguide with multiple scatterers and without scatterers. The effects of the random media on the choice of the parameters of the signal processing are also studied.
Broadband class I flextensional transducer
Authors: Lan Yu , Lu Wei , Sang Yongjie , Zhou Tianfang
Published: May 2014

Researches about high-power, low-frequency projectors are the most important technology for long range sonar systems. Flextensional transducer is a typical low-frequency, high-power projector, which has the advantages of small volume and light weight due to displacement amplification. In this paper, attention is focused on expanding bandwidth of the flextensional transducer. Class I flextensional transducer usually consists of a slotted convex shell and a driving stack. There are two kinds of main vibration modes at low frequency, the first flexural mode and the membrane mode. They can be coupled and broadband transmitting response was obtained. Finite element (FE) techniques are applied to the design of this multiple-mode-coupling transducer. Finite element model was made with ANSYS software and it can be used to do vibration mode analyze, operative mode simulation and structure optimization. Base on the analyze results, the multiple-mode-coupling flextensional transducer was designed and tested. Key words: flextensional transducer; broadband; multiple-mode-coupling; Finite Element Method
Doubly resonant underwater acoustic transducer for long distance sound propagation
Authors: Morozov Andrey K.
Published: May 2014

The presentation describes the design and test of innovative deep water low frequency sound source for long range acoustic communications and navigation. The light-weight, low frequency (200–1000 Hz), broadband underwater sound source comprises an inner resonator tube with thin walls tuned to a certain frequency surrounded by a shorter, larger-diameter, lower frequency tuned outer resonator tube. These resonating tubes are opened on both ends and made of carbon fiber. The tubes are asymmetrically shifted along the main axis and sound pressure can penetrate from internal pipe though the area under the shifted external pipe into that external pipe and back. By changing length of shifted area the coupling coefficient of two resonators can be regulated to achieve a necessary bandwidth. The design uses depth independent oil-filled acoustic transducer. The transducer is light, operational for all ocean depth, and reasonably broadband. A multiresonant systems usually need a precise complicated adjustment of their parameters to get necessary bandwidth with limited variability of frequency response inside the frequency range. It can be even more complicated, when design includes new, never tested before, materials. Application of finite element analysis allowed to predict necessary parameters and avoid a long series of water tests with parameters adjustment.
Sensing stratified turbulence and shear instability using an acoustic high frequency broadband backscatter array
Authors: Fincke Jonathan R. , Lavery Andone
Published: May 2014

High-frequency broadband acoustical backscattering measurements with an array of transducers have allowed the temporal and spatial evolution of shear instabilities in a strongly stratified estuarine environment to be investigated. Development of accurate remote sensing techniques for estimating mixing are of significant interest to the geophysical fluid dynamics community. An array of six high-frequency (120–600 kHz) broadband and narrow beam width (1 to 6 degrees half-beamwidth, depending on the frequency) transducers spaced 1.2 m apart were deployed in the Connecticut River estuary both in the along stream and across stream direction to observe high Reynolds number stratified shear instabilities. In this presentation, results of these high-resolution temporal and spatial sampling measurements of shear instabilities are shown. These measurements demonstrate the utility of these techniques for improving our understanding of the evolution of shear instabilities.
Passive acoustics embedded on gliders—Weather observation through ambient noise
Authors: Cauchy Pierre , Testor Pierre , Mortier Laurent , Beguery Laurent , Bouin Marie-Noelle
Published: May 2014

Underwater gliders can provide high resolution water temperature and salinity profiles. Being able to associate them with a surface weather conditions estimation would allow to better study sea-air interactions. Since in-situ observations of the marine meteorological parameters are difficult, the development of a glider embedded weather sensor has been studied, based on the WOTAN approach. In the 1–30 kHz frequency range, the background underwater noise is dominated by wind generated noise. Focusing on the sound pressure level at 5, 8, 10, and 20 kHz allows to estimate the wind speed. Thus, deploying a glider with an embedded hydrophone gives an access to the surface weather conditions around its position. We have deployed gliders in the Mediterranean sea, with passive acoustic monitoring devices onboard. Four months of data have been recorded. Wind speed estimations have been confronted to weather buoys observations and atmospheric models predictions. Wind estimates have been obtained with a ~2 m/s error. A specific emphasis has been placed on the robustness of the processing through multi frequencies analysis and depth induced attenuation correction. A downscaling study has been performed on the acoustic sampling protocol, in order to meet the low energy consumption glider standards, for a future real time embedded processing. The glider generated noise and its vertical movement are not perturbing the estimation. Moreover, the surface behavior of the Slocum gliders allows an estimation of the wind direction.
Nonlinear acoustic waves in media with hysteresis and long-time relaxation
Authors: Ostrovsky Lev A.
Published: May 2014

It is known that the media with complex structures (e.g., rocks and ceramics) possess an anomalously strong elastic nonlinearity. Nonlinear acoustic effects are used in a number of important applications, such as seismic waves (earthquakes), non-destructive testing, and contact physics. Two specific features were registered, in most of the experiments: hysteresis in the stress-strain relation and longtime relaxation (slow time). Some physical models, mostly phenomenological, have been suggested to explain these phenomena. However, there are very few works considering the effect of medium hysteresis and relaxation on wave propagation and oscillations in resonators. This presentation is a review of both published and new results in this area. Among the problems discussed are: (1) A brief overview of experiments and models; (2) Analysis of wave propagation in simplified models of media with hysteresis as opposed to the nonlinear waves in media characterized by elastic constants of second and third order; (3) Theory of wave interaction in resonators with hysteresis; (4) Study of waves in media with slow time relaxation; (5) Some data from laboratory and field experiments; (6) Some unsolved issues and the relevant future work will be outlined in conclusion.
Nonlinear collapse of vortex
Authors: Naugolnykh Konstantin A.
Published: May 2014

Sound radiation by two vortices with different intensity and sign changes the distribution of vortex field. The acoustic instability and vortices motion may occur in such a system. The linear stage of this process was considered previously the spread of similar vortices (Klyatskin, 1966) and attraction of different vortices (Gryanik, 1983; Kop'ev and leont'ev, 1983). As a result of attraction, the nonlinear effect of collapse of vortices may appear. This process is considered by the method of matched asymptotic expansion of the solution for the point vortices in an incompressible fluid and the solution of nonlinear Burgers equation. The features of cylindrical wave spread and nonlinear distortion both indicated.
Analysis of scattering from dual-frequency Incident beam interaction
Authors: Nguon Chrisna , Misiunas Nicholas , Deschamp Barbara , Chandra Kavitha , Thompson Charles
Published: May 2014

The characterization of acoustically inhomogeneous structures insonified by dual-frequency acoustic beams is undertaken. A layer of microbubble contrast agents is included to improve the resolution of the scattered field. Of particular interest is the identification of characteristic sizes of volume scatterers and their principal orientations by measurement of their acoustic signatures in the exterior field. The inclusion of bubble contrast agents has shown to enhance the directional pattern of the back-scattered field generated from the difference frequency source created by the nonlinear interaction of the incident beams. However, the sensitivity of the scattered field to variations in the contrast parameter and spatial orientation requires computation to be carried out in a high-dimensional parameter space that includes the difference wavenumber, angle of incidence, acoustic nonlinearity parameter, and several microbubble parameters. A fast computation of the exterior field is carried out using a monopole expansion of the Green's function that separates the source and observation coordinates. The exterior field is sampled and analyzed in the aforementioned system parameter space to identify the weighted combination of parameters that serve as a minimum representation for detecting the changes in the medium parameters through measurements of the exterior scattered field.
Sound transmission issues in higher-story fitness facilities
Authors: Paley Sharon
Published: May 2014

The growing popularity of Crossfit and other high-intensity workouts coupled with an increasing trend for gyms/weight rooms to be installed on higher stories of lighter-weight buildings is casting a new light on sound transmission issues in fitness facilities for the acoustic consultant. Traditional gym flooring and mats do not sufficiently minimize the impact of a dropped dumbbell for the tenant below. This is a growing problem for both residential gyms found in multi-family housing as well as the more extreme facilities for professional athletes and olympians. Field test results, limitations of existing field measurement techniques, and potential solutions will be discussed.
Sound and noise in high schools gymnasiums
Authors: Carvalho Antonio P. , Barreira Carla C.
Published: May 2014

The goal of this research was to characterize the interior acoustics of high schools sports facilities using objective parameters. In situ measurements were done in 68 school gymnasiums in Portugal (volume from 450 to 2680 m3) regarding LAeqBN (background noise without gym classes), LAeqPE (ongoing Physical Education classes), RT, and RASTI. The results for LAeqBN were from 34 dB (L90) to 50 dB (L10) with a median of 42 dB. For the LAeqPE were found values from 75 dB (L90) to 85 dB (L10) with a median of 80 dB. For the RT(500/1k/2k) room values from 2.6 s (RT90%) to 6.9 s (RT10%) with a median of 4.8 s, were measured. The room average RASTI values were from 0.27 (RASTI90%) to 0.43 (RASTI10%) with a median of 0.34. These sports rooms proved to be highly reverberant, almost without sound absorbing materials, which might be harmful, especially for the gym teachers. The subjective perception of the PE teachers was analyzed through questionnaires where it was verified that they feel most discomfort when it comes for noise (and thermal) conditions. This was supported by the objective results obtained. Ideal values for those acoustic parameters are presented.
Infant-directed speech reduces English-learning infants preference for strong/weak versus weak/strong words
Authors: Houston Derek , Spann Crystal
Published: May 2014

Mounting evidence suggests that infant-directed speech (IDS) facilitates aspects of language acquisition. An important milestone of English-learning infants' language acquisition is encoding the predominant stress-initial rhythmic structure of English, which 9-month-olds have demonstrated by showing a looking-time preference for lists of strong/weak words (e.g., doctor) versus weak/strong words (e.g., guitar) (Jusczyk et al., 1993). We tested for this preference in 48 9-month-olds using the headturn preference procedure. Twenty-four infants were presented with the words using IDS, and 24 were presented with adult-directed speech (ADS). Infants were presented with a visual display of a blinking light on one of two (left and right) monitors. When they oriented toward the monitor, a list was presented from behind that monitor until they looked away for more than 2 s. They were presented with lists of weak/strong words for half the trials and strong/weak words for the other half in quasi-random order. A repeated-measures AVOVA revealed a statistically significant interaction between word-type preference and speech condition. To our surprise, only infants in the ADS condition showed a preference strong/weak words. The findings raise the possibility that rhythmic properties of words may be more difficult for infants to encode in IDS than ADS.
Do elementary school children eat less in noisy cafeterias?
Authors: Ermann Michael , Serrano Elena L. , Byker Carman , Calvey Robert
Published: May 2014

Twenty years ago, the increased occupant productivity linked with high performance, LEED, green, sustainable, Passivhaus, and day-lit buildings was generally backed by anecdote. A flurry of recent research, however, has consistently confirmed the once-anecdotal narrative: when buildings perform better, workers do more, students learn more, and sales spike. After a substantial financial investment in a high performance building, owners can expect meaningful energy savings with modest payback times, but for buildings where occupant performance has a value, both the construction costs and energy savings are a rounding error relative to occupant productivity benefits. Geothermal and passive thermal systems are explored as opportunities to align low-energy thermal systems to acoustics; passive ventilation and thermal mass are explored as low-energy thermal comfort strategies that challenge acoustic concerns. The author’s recent research in daylighting, thermal mass, night insulation, and the effects of cafeteria noise on the eating habits of elementary school children will be highlighted.
Near real-time detection, beam-forming, and telemetry of marine mammal acoustic data on a wave glider autonomous vehicle
Authors: Cheyne Harold A. , Hawthorne Dean , Key Charles R. , Satter Michael J.
Published: May 2014

Impacts of anthropogenic noise on marine mammals are becoming increasingly important for regulatory and research study, yet assessing and mitigating these impacts is hindered by current technology: archival underwater acoustic recorders have their data analyzed months after the activity of interest, and towed hydrophone arrays suffer from nearby ship and seismic air gun noise. This work addresses these drawbacks by developing an acoustic data acquisition and transmission system for use with a Wave Glider, to provide near real-time data for marine mammal monitoring and mitigation. The goal of the system is to be capable of months of autonomous monitoring in areas that would otherwise not be surveyed, and to transmit acoustic data within minutes of acquisition to enable rapid mitigation. Sea tests have demonstrated the proof-of-concept with the system recording four channels of acoustic data and transmitting portions of those data via satellite. Ongoing work is integrating a detection-classification algorithm on-board the Wave Glider and a beam-forming algorithm in the shore-side user interface, to provide the user with a topographic view of the Wave Glider; a sound source direction estimate; and aural and visual review of the detected sounds.
Numerical study of Rayleigh-type acoustic streaming based on a three-dimensional incompressible flow model
Authors: Yano Takeru
Published: May 2014

Rayleigh-type acoustic streaming induced by a plane standing wave in a rectangular parallelepiped is numerically studied on the assumption that the streaming motion is an incompressible flow and induced by the so-called limiting velocity on the outer edge of the acoustic boundary layer on the wall of the rectangular parallelepiped. Solving the three-dimensional incompressible flow equations with a standard finite difference scheme, we show that the streamline indicates chaotic behaviors even when the streaming velocity field converges to a time-independent state (steady flow) for moderate Reynolds numbers. Based on the result, we can discuss an efficiency of mixing by the time-independent Rayleigh-type acoustic streaming motions in three-dimensional boxes.