bluuebunny/crossref_metadata_2025 huggingface dataset:
Using resonant ultrasound spectroscopy on samples with and without conducting coatings to measure piezoelectric constants
Authors: Vieceli Rhiannon E. , Maynard Julian D.
Published: May 2014

Piezoelectrics are often used at low temperatures, but among the large number of piezoelectric materials, only one (quartz) has had its properties measured at low temperatures. Because measuring piezoelectric constants with the traditional electrical impedance method has shortcomings, particularly at liquid helium temperatures, it would be advantageous to make measurements with resonant ultrasound spectroscopy (RUS). EerNisse and Holland (1967) established a theoretical basis and Ogi et al. (2002) demonstrated an experimental RUS method. A problem with RUS for piezoelectrics is that resonance frequencies are much more sensitive to elastic behavior than to piezoelectric behavior, so that extraordinary precision is required. However, one may make a RUS measurement on a sample twice, once with an electrically conducting coating on sample faces and once without, and analyze the differences in the frequency spectra. Because the effect of the conducting coating depends more on the piezoelectric behavior than on the elastic behavior, analyzing the frequency differences suppresses the dependence on the elastic constants and enhances the measurement of the piezoelectric constants. This paper will present theoretical and experimental results for this RUS method.
Possible contribution of cochlear compression to amplitude modulation detection
Authors: Lee Jungmee
Published: May 2014

Among his many research areas, Sid Bacon's work on auditory temporal processing, and his effort to connect psychophysical phenomena with cochlear compression, contributed greatly to our understanding of auditory system function. Inspired by his work, I will present research suggesting that (1) temporal processing, as measured by amplitude-modulation (AM) detection, is better for people with cochlear hearing impairment (HI) than those with normal hearing (NH) when the age of groups and loudness of the stimuli is matched, (2) AM detection of a target is poorer when an AM masker is presented at frequencies in a region with hearing loss than in a region of normal hearing, (3) masking of AM detection by an AM masker is reduced in HI when the masker is compressed using a low-distortion compressor, but is unaffected for NH, and (4) amplitude modulation of 2f1-f2, Distortion Product Otoacoustic Emissions recorded with amplitude-modulated f1 and steady-state f2, is correlated with AM perception. Taken together, the results provide evidence that cochlear compression plays an important role in auditory temporal processing as measured by AM perception.
The role of pitch strength in extracting speech from complex backgrounds
Authors: Leek Marjorie R.
Published: May 2014

How do people extract a target speech signal from a chorus of other sounds including other speech sounds? And what are the central and peripheral auditory processes that make this possible, and that may fail in people with damaged auditory systems? These critical issues in speech and hearing science were of continuing interest to Sid Bacon throughout his career. As Sid has noted, the problem is multifaceted, and he chose to study many of the individual factors, as well as their interactions. In keeping with that approach, I will discuss how normal-hearing and hearing-impaired listeners use pitch to extract a target from a complex noise background. In one study, auditory stream segregation of iterated rippled noises (IRN) with varying pitch strengths was explored to understand the limits of tonality for separating two patterns of sounds. In a second study, voice pitch strength was investigated as a means to support perceptual separation of target and background speech, with a focus on either spectral or temporal characteristics of the speech sounds. Interactions between degree of tonality in speech and other factors related to perception of speech in background sound will be examined. [Work supported by NIH.]
Understanding the benefits of electric-acoustic stimulation
Authors: Brown Christopher
Published: May 2014

The problem of speech understanding in the presence of background noise is a difficult one, especially for users of cochlear implants. Although these users can often perform well on speech tasks in quiet, they typically show rapid declines in background noise. The retention of low-frequency residual acoustic hearing has been shown to provide significant benefit in this regard. Data will be presented on our work on this topic, from characterizing the benefit to exploring ways of providing it to cochlear implant users who do not show a benefit typically.
Acoustic horn reflectance: Equations and measurements
Authors: Neely Stephen T. , Rasetshwane Daniel
Published: May 2014

Reflectance is the transfer function between forward and reflected components of pressure waves that propagate in wave guides such as acoustic horns. Exact solutions to Webster's Horn Equation are only known for a few specific shapes, including parabolic, conical, and exponential. Explicit equations for reflectance in these three horn shapes were recently published for infinite-length horns. Measured reflectance in 3D-printed, finite-length examples of these horn shapes, show no similarity in the frequency-domain to exact reflectance for infinite-length horns. The similarity improves after adjustments to both the equations and the measurements. New equations were derived for exact reflectance of finite-length horns. Measured reflectance was smoothed by time-domain windowing. In contrast to frequency-domain reflectance, comparisons of time-domain reflectance prior to the time sound reaches the end of the horn were not much affected by these adjustments. Because exact equations are known and 3D-printed examples are easy to obtain, these three horn shapes may be useful as standards for comparing different reflectance-measurement systems.
The role of amplitude modulation in auditory distance perception
Authors: Zahorik Pavel , Anderson Paul W.
Published: May 2014

The ratio of direct to reverberant sound energy (D/R) has been shown to be a primary acoustic cue to perceived sound source distance. Because it is unclear exactly how D/R might be encoded in the auditory system, a variety of more physiologically plausible correlates to D/R have been identified, including: spectral variance, interaural correlation, and temporal cues. Here, following recent neural work by Kuwada and Kim [ARO (2014)], we describe a new correlate to D/R and perceived distance related to the amplitude modulation (AM) depth of the signal at the listener's location. This cue is caused by the change in the modulation transfer characteristics of the room as a function of source distance. Results from an apparent distance estimation task confirm the efficacy of this AM depth cue in a reverberant soundfield (approximate broadband T60 = 3 s), when level cues are made ineffective. Distance estimates were found to be more accurate when the source signal (1-octave band of noise centered at 4 kHz) had AM (32 Hz, 100% depth), and this facilitation was only observed in reverberation. The facilitation was most evident for monaural input, indicating that the AM depth cue is likely processed monaurally.
Weighting of interaural time difference and interaural level difference cues in wide-band stimuli with varying low and high frequency energy balance
Authors: Macpherson Ewan A. , Nguyen Tran M.
Published: May 2014

Wideband stimuli carry both interaural time and level difference (ITD and ILD) sound location cues. Previously, listener weighting of those cues has only been measured for low-pass, high-pass, and flat spectrum wide-band conditions [Macpherson and Middlebrooks, JASA (2002)]. In this study, we determined how weighting of ITD and ILD cues varied with the low- and high-frequency energy balance in wide-band stimuli. Listeners reported locations of targets that were presented over headphones using individual head related transfer functions. ITD and ILD cues were manipulated by attenuating or delaying the sound at one ear (by up to 300μs or 10dB), and the final weight was computed by comparing the listener's localization response bias to the imposed cue bias. Stimuli were 100-ms bursts of noise whose spectra were flat from 0.5 to 2 kHz and from 4 to 16 kHz with a level difference between those low- and high-frequency ranges varying in 10-dB steps from −30 to + 30 dB. ILD weight increased (from ~0.5 to 1.5 deg/dB) with increasing high-frequency energy, but ITD weight was constant (~0.08 deg/us) across spectral profiles. The results suggest that in wideband stimuli, weighting of ILD is more stimulus dependent than weighting of ITD.
Just noticeable difference of source-receiver distances in the auralization process using speech and music signals
Authors: Murta Bernardo , Wunderlich Priscila , Lins de Souza Jessica J. , Paul Stephan
Published: May 2014

The precision of source-receiver transfer functions is of importance to provide reliable and ecologically valid results in auralization. Recently the overall just noticeable difference (jnd) in signals obtained from the convolution of music with slightly varying source-receiver transfer functions was determined using a paired comparison procedure (sound are equal/are different) and estimating the jnd from the 75% point on the psychometric curve. JNDs were 3.55 cm for dislocations approaching the source and 3.46 cm if going away from the source. Now we present the results from tests using a speech signal convolved with the same simulated impulsive responses of different source-receiver positions making 3 sets of 23 stimuli pairs. Each one represents receiver dislocations in one dimension: x, y, and z. The jnd using a speech signal was found to be 3.86 cm when approaching the source and 3.97 cm for the opposite direction. The difference calculated between the jnd of the two tests was 0.314 cm (approaching the source) and 0.506 cm (in the opposite direction). Further tests will be done using noise signals and an overall jnd will be computed.
The role of physics in inner-ear physiology and auditory perception
Authors: de Boer Egbert
Published: May 2014

Auditory analysis of acoustical stimuli has mainly been connected with Fourier analysis. This touches the basic link between auditory perception and the operation of the hearing organs, namely, physics and mathematics. This relation has amply been demonstrated by the work and ideas of Georg von Békésy. Later, the healthy cochlea (inner ear) was found to contain amplifying elements that boost frequency selectivity. Associated with this there is a pronounced nonlinearity. Furthermore, the ear does not only absorb and process sounds, it also emits sound waves. Mathematical models of all these processes must contain subsets serving them all, a goal that has not yet been reached. On the contrary, recent findings on the movements of the various membranes and cells in the organ of Corti have increased the difficulties of mathematical modeling. Additional subjects to be covered in the lecture are (1) in psychophysics of hearing: pitch perception, inharmonic sounds, critical bands, hearing of patients with hearing loss, and auditory revalidation, and (2) in auditory neuroscience: recording of single fibers of the auditory nerve, reverse correlation, inverse solutions of cochlear mechanics, nonlinear analysis, and optical coherence tomography (OCT).
Murray Strasberg's contributions to acoustic cavitation and bubble dynamics
Authors: Crum Lawrence.”
Published: May 2014

Although Murray Strasberg's most significant contributions to acoustics were classified and not available to the general public, he also published some significant papers in the general area of acoustic cavitation and bubble dynamics. Some of these papers are so fundamental in scope that I consider them required reading for any new graduate student that joins our group. At cavitation sessions in the ASA, Murray was always asking insightful questions that amazed others who did not know of his pioneering work on this topic. In this presentation, I will describe some of Murray's contributions to bubble dynamics and cavitation as well as relate some personal observations of my interactions with him over our respective professional careers.
Oscillations of nonspherical and spherical bubbles
Authors: Marston Philip L. , Asaki Thomas J. , Thiessen David B.
Published: May 2014

Murray Strasberg maintained an interest in bubble oscillations throughout his career and frequently offered an incisive perspective. His early bubble research includes [Strasberg, J. Acoust. Soc. Am. 25, 536–537 (1952); Strasberg, Acustica 4, 450 (1954)]. His pertinent application of an electrostatic potential theory analogy expands interests of some of James Clerk Maxwell's students. In addition some related discussions with Murray will be recalled and experiments from the 1980s and 1990s at Washington State University pertaining to bubbles and their associated dynamics reviewed. Those experiments concern the response of bubbles to steady and modulated optical radiation forces [Unger and Marston, J. Acoust. Soc. Am. 83, 970–975 (1988); Unger and Marston, Ocean Optics IX, Proc. SPIE 925, 326–333 (1988)] and to modulated acoustical radiation forces [Asaki et al., Phys. Rev. Lett. 75, 2686–2689, (E) 4336 (1995); Asaki and Marston, J. Fluid Mech. 300, 149–167 (1995); Asaki and Marston, J. Acoust. Soc. Am. 102, 3372–3377 (1997)]. The latter papers pertain to the simultaneous measurement of the frequency and damping of bubble shape oscillations. [Work supported by ONR.]
Draft American National Standard: Methods for measuring the vibration response of the ground
Authors: Phillips James E.
Published: May 2014

Working Group 14 of the Acoustical Society of America/American National Standards Institute S2 Mechanical Vibration and Shock Committee (ASA/ANSI S2 WG14) was formed to develop a standard on methods for measuring the vibration response of the ground to be used when assessing potential impact upon vibration sensitive receivers in the vicinity of rail transit systems. The contents of the standard will be based upon industry accepted methods as described in the Federal Transit Administration guidance manual “Transit Noise and Vibration Impact Assessment” (FTA-VA-90-1003-06) while considering new developments since the latest version of the guidance manual was published in May 2006. This paper will describe the background of the methods and the structure, content, and status of the draft standard.
Predicting indoor groundborne noise and vibration levels from transit sources
Authors: McKenna Shannon
Published: May 2014

The groundborne noise and vibration impact thresholds in the Federal Transit Administration (FTA) Noise and Vibration Impact Assessment guidance manual apply to indoor spaces. Therefore, the prediction methodology must account for how the building structure affects groundborne vibration through floor resonances and coupling loss and how the building affects groundborne noise through sound absorption or radiation. This presentation will include measurement results that illustrate the variation in building response to vibration. Due to the large number of vibration sensitive receivers that may be adjacent to a proposed transit line, it can be difficult to account for the variation in building response throughout the corridor when only a limited number of measurements sites are available or practical. Case studies will be presented that include recommendations for how measurement results can be incorporated into the prediction procedure.
Application magnetorheological elastomer to dynamic vibration absorber for vibration reduction by avariable-unbalance excitation
Authors: Jeong Unchang , Kim Jin-Su , Yoon Jung-Min , Oh Jae-Eung
Published: May 2014

This paper presents a concept of dynamic vibration absorber (DVA) applied magnetorheological elastomers (MREs) for vibration reduction. Elastic modulus of MRE significantly increases due to the induced magnetic field. Elastic modulus changes the stiffness of DVA. Thus, the DVA can work effectively in a wide frequency range instead of a narrow bandwidth as a conventional dynamic vibration absorber does. Numerical simulations of avariable-unbalance excitation system are used to validate its effectiveness. Thus, the MRE-DVA will be applicable to the vibration reduction.
Intrinsic fundamental frequency (F0) in American English vowels is affected by regional variation
Authors: Fox Robert A. , Jacewicz Ewa
Published: May 2014

There is a relationship between F0 values and vowel height: High vowels have higher F0 than low vowels. A long-standing debate has centered on whether this intrinsic F0 (IF0) pattern is an automatic consequence of vowel articulation or whether it represents deliberate effort to enhance vowel contrast. We provide new data from regional variation suggesting that IF0 is partly controlled by the speaker. F0 was analyzed in high, mid, and low vowels, stressed and unstressed, in 36 females representing dialects spoken in Ohio, Wisconsin, and North Carolina. A robust finding was that dialects differ in their use of IF0 in stressed vowels: IF0 differences between high and low vowels in North Carolina were significantly smaller than those in Ohio and Wisconsin for measurements at vowel onset, offset, peak F0, and overall F0. High vowels had higher IF0 than low vowels in all dialects, confirming the universal aspect of IF0. However, the magnitude of this difference was dialect-specific, which suggests a relative independence of IF0 from vowel height. The lack of correspondence between dialect-specific formant values and dialect-specific IF0 indicates that the quality of vowels and their IF0 value are two features that need to be learned separately.
Production and perception of the English sibilants /s/ and /∫/ in persons with Parkinson's disease
Authors: Chen Yu-Wen , Watson Peter J.
Published: May 2014

Parkinson's disease (PD) presents with both sensory and motor deficits including speech, characterized by soft voice, monotonicity, and imprecise articulation. Both audition and somatosense are believed important for accurate speech production. Individual studies have identified auditory impairment and somatosensory impairment of the orofacial structures and the larynx. No studies have examined the relationship between imprecise articulation and sensory impairment. This research aims at examining sensory deficits and the relationship between sensory deficits and imprecise articulation in persons with PD. The production of /s/ and /∫/, auditory discrimination and identification in spectral shape, and somatosensory acuity on the tongue tip are examined. In the production task, participants read monosyllabic words beginning with /s/ and /∫/ embedded in a carrier sentence; measures of spectral shapes are made. Auditory tasks comprise an acuity task testing for participants' auditory acuity in perceiving spectral shapes and a /s/-/∫/ categorization task testing for their categorical boundaries. The somatosensory acuity task tests for participants' somatosensory acuity in spatial orientation on the tongue tip. Relationships between production of /s/ and /∫/ and sensory performance are tested in correlational tests.
Automated classification of oncoming ground vehicles using acoustic echolocation and supervised machine learning
Authors: Dieckman EricA. , Hinders Mark K.
Published: May 2014

In order to perform useful tasks, robots must have the ability to notice, recognize, and respond to objects in their environment. This requires the acquisition and synthesis of information from a variety of sensors. Here we focus on acoustic echolocation measurements of approaching vehicles, where an acoustic parametric array propagates an audible signal to the oncoming target and the reflected backscattered signal is recorded using the Microsoft Kinect microphone array. Although useful information about the target is hidden inside the noisy time domain measurements, the Dynamic Wavelet Fingerprint process (DWFP) is used to create a time-frequency representation of the data. Intelligent feature selection allows the creation of a small-dimensional feature vector that best differentiates between vehicle types for use in statistical pattern classification routines. Using experimentally measured data from real vehicles at 50 m, this process is able to correctly classify vehicles into one of five known classes with 94% accuracy. Fully three-dimensional simulations allow us to study the nonlinear beam propagation and interaction with real-world targets to improve classification results.
A method for deconstructing the relaxation absorption spectrums of gas mixtures
Authors: Liu Tingting , Wang Shu , Zhu Ming
Published: May 2014

It is acknowledged that the relaxation absorption spectrum curves can be employed to detect gas compositions. However, it still remains a challenge to extract the composition information from the spectrums. In this paper, a method is proposed for deconstructing the relaxation absorption spectrums of a gas mixture. Based on the deconstruction results, a gas relaxation absorption spectrum is constituted by the curve tendency, which is determined by the gas effective specific heat, and the curve position, which is determined by the gas effective relaxation time. And the effective specific heat of a gas mixture is the simple addition of the compositions' independent effect, while the effective relaxation time is the complex interaction effect between different compositions. Consequently, the deconstruction method can deconstruct the relaxation absorption spectrums of a gas mixture into the simple sum of its compositions' spectrums. By the comparison between the theory curves and the experimental data, the validity of the deconstruction method is proved. The method holds great potentials for the obtainment of composition information in gas detection.
Characteristics of sounds detected and localized in Hawaiian waters in Oct. 2013 believed to be from a Bryde’s whale
Authors: Martin Stephen W. , Matsuyama Brian M.
Published: May 2014

Pulsed acoustic sounds suspected to be from a single Bryde’s whale (Balaenoptera edeni) were automatically detected and localized in real time between 1130 and 1304 local time on 6 August 2013 utilizing hydrophones at the Pacific Missile Range Facility, Hawaii. The bottom mounted hydrophones are located 40 km to 80 km northwest of the Napali Coast of Kauai in waters over 4 km in depth. The localized sounds moved from east to west on a course of 294 degrees true for a distance of ~21.6 km with an average speed of 13.8 km/h, which is within the range reported for Bryde’s whales. The sounds resemble those previously identified as being from Bryde’s whales associated with visual sightings (Oleson et al. 2003) and acoustic only observations (Heimlich et al. 2005). Detailed analysis of the sounds revealed 27 emissions over the period with an inter-pulse interval of 216.6 s (SD, 69.4 s; range, 33–358 s). The duration of the sounds was approximately 1.8 s with major energy apparent at 33 Hz exhibiting burst tonal characteristics often with lower frequency tonal content. Generic calibration data for the hydrophones allows estimation of the source levels of the sounds, which fit within the range previously reported for the species (Cummings et al. 1986).
Acoustic characterization and vocal behavior of North Atlantic right whale surface active groups
Authors: Gerstein Edmund R. , Trygonis Vasilis , Moir Jim , McCulloch Steve
Published: May 2014

Focal acoustic surveys were conducted to assess the vocal behavior of North Atlantic right whales in the shallow waters of the southeast critical habitat. Underwater vocalizations were archived using autonomous buoys in close proximity to surface active groups (SAGs) providing sound production data vital for regional passive acoustic monitoring and conservation. Classification trees were used to examine the distinguishing characteristics of calls and quantify their variability within the surface active groups vocal repertoire. Calling rates were higher than those reported in the Bay of Fundy, which may be a factor of habitat demographics. Sound production rate and call type usage were correlated with group cohesion, revealing a consistent call distribution pattern across SAGs of varying sizes and composition. The within-bout clustering probability of low and high frequency calls suggest that temporal affinities between vocalization classes may be indicators of shared social functions. The results demonstrate that concurrent temporal and spectral analysis is powerful for investigating and presenting the interrelationships of calls with social behavior and group composition.
Ultrasound for microvascular tissue engineering
Authors: Dalecki Diane , Hocking Denise C.
Published: May 2014

A critical obstacle currently facing the field of tissue engineering is the need for rapid and effective tissue vascularization strategies, both during construct development and upon implantation. To address this challenge, we have developed an ultrasound technology for microvascular tissue engineering. The technology utilizes radiation forces in an ultrasound standing wave field to rapidly and non-invasively spatially pattern cells in 3D within hydrogels. Ultrasound-induced patterning of endothelial cells accelerates the emergence of capillary-like sprouts stimulates cell-mediated collagen fibril alignment and results in the maturation of sprouts into lumen-containing microvessel networks throughout collagen hydrogels. Importantly, the morphology of resultant microvessel networks can be controlled by design of the acoustic field employed during fabrication. Specifically, the technology can produce microvascular networks having two distinct, physiologically relevant morphologies; one composed of a tortuous, capillary-like network, and one composed of hierarchical branching vessels (arteriole/venule-like). We have extended the versatility of the technology to lymph endothelial cells and have demonstrated the ability to engineer 3D lymphatic microvessel structures. Thus, this ultrasound technology holds promise as a new approach to induce microvascular network formation and direct vascular morphology in engineered tissues.
Massachusetts Wind and Noise Technical Advisory Group—Status report
Authors: Menge Christopher W. , ONeal Robert D.
Published: May 2014

In June 2013, the Commonwealth of Massachusetts launched a Community Wind Energy Initiative to provide support and guidance to municipalities, developers and stakeholders for land-based wind projects. The initiative convened a technical advisory group of experts to solicit input on wind turbine sound policy. This Wind and Noise Technical Advisory Group (WNTAG) is led by the Massachusetts Department of Environmental Protection (MassDEP) and includes other state agency representatives, wind energy experts, industry representatives, affected community representatives, health experts, and acoustical consultants. The WNTAG has met several times since July 2013 and has addressed many aspects of wind turbine noise that may influence and/or become a part of a new statewide noise policy for land-based wind turbines. In this presentation, the authors provide perspective on the process, progress toward a revised policy, and the policy and technical aspects that were discussed, which included absolute vs. relative noise criteria, noise level metrics, measurement protocols for compliance evaluation, amplitude modulation, and modeling approaches for pre-construction permitting.
Update on regulations adding noise to hybrid and electric cars
Authors: Weidemann Dennis , Blomberg Leslie D.
Published: May 2014

The United States National Highway Traffic Safety Administration in nearing and may have completed is rulemaking concerning adding noise to hybrid and electric cars by May 2014. This paper will examine what has happened in early 2014 with respect to these regulations. Updates to international regulations will also be presented.
Investigating human annoyance thresholds of tones in noise from a dose-response relationship
Authors: Lee Joonhee , Francis Jennifer M. , Wang Lily M.
Published: May 2014

Noise with prominent tones from building mechanical systems is often detrimental to the environmental quality and leads to complaints. Previous studies have investigated the relationship between existing tonal noise metrics and human annoyance perception, but little is known about at what level the tones at assorted frequencies induce human annoyance. This paper investigates human annoyance responses due to noise with tones to produce a dose-response relationship for estimating the thresholds of annoyance to tones in noise. The subjective test is conducted using noise signals with varied loudness and tonalness thorough an Armstrong i-Ceiling system in the Nebraska indoor acoustic testing chamber. Binary logistic multiple regression models are used to predict the percentage of annoyed people or likelihood-to-complain with confidence intervals. This paper also examines the statistical performance of models with assorted noise metrics and non-acoustical variables to calculate the probability of occupants feeling annoyed for any given background noise with tonal components.
Prediction of acoustic radiation forces in three dimensional flow through resonators
Authors: Mercado Ari , Lipkens Bart
Published: May 2014

In large scale acoustophoretic particle separation systems, the acoustic radiation force exerted on the particles exceeds the combined effect of the fluid drag force and gravitational force on the particle. This results in the trapping of the particles in the acoustic standing wave, followed by aggregation of the particles, and ultimately gravitational settling and separation of the secondary phase. The separation system typically consists of a flow chamber in which a three dimensional acoustic standing wave is generated by piezoelectric transducers. Accurate prediction models of the acoustic radiation force are needed so that they can be used as a tool in the design and development of such separation systems. The prediction model consists of two steps. First, COMSOL Multiphysics ¯ software is used to predict the acoustic field in the separation devices. Next, theoretical models [Gor’kov, Sov. Phys. Dokl. 6, 773–775 (1962) and Ilinskii et al., J. Acoust. Soc. Am. 133, 3237 (2013)] are used to calculate the acoustic radiation force on a suspended particle. Numerical results were verified by comparison with the theoretical results for a rectangular cavity [Barmatz and Collas, J. Acoust. Soc. Am. 77, 928 (1985)]. [Work supported by NSF PFI:BIC 1237723.]
Design of a multi-element transducer for large volume acoustophoretic phase separation
Authors: Dionne Jason P. , Lipkens Bart
Published: May 2014

Efficient separation technologies for multi-component liquid streams that eliminate waste and reduce energy consumption are needed. In previous experiments around this novel platform technology, a single element transducer has been used to generate a high intensity three-dimensional ultrasonic standing wave resulting in an acoustic radiation force that is larger than the combined effects of fluid drag and buoyancy. Acoustic trapping of particles followed by enhanced gravitational settling is used to separate the secondary phase. A typical transducer is made of a PZT-8 2-MHz ceramic. This work reports on the comparison of the performance of a single element transducer to that of a multi-element transducer. Parametric simulation studies of multi-element transducer designs were performed to accurately predict the acoustic pressure field in the fluid flow with the goal of generating large acoustic radiation forces to assist in phase separation. COMSOL Multiphysics ¯ was used to run simulations and results were compared to an experimental prototype that consisted of a 2-in. by 1-in. flow chamber driven by a 1-in. by 1-in. 2-MHz transducer. The designs of the multi-element transducers consisted of two PZT-8 2-MHz transducers; one consisting of 16 elements and another of 25 elements. [Work supported by NSF PFI:BIC 1237723.]
Psychophysics to the rescue! Translational hearing research in Cambridge
Authors: Carlyon Robert P.
Published: May 2014

Roy Patterson and Brian Moore, perhaps more than any other psychoacousticians, have succeeded in applying their research for the common good. Those who have benefited from this translation of basic research include users of hearing aids and of auditory warnings. I will describe the results of recent experiments aimed at improving hearing by another group, namely users of cochlear and auditory brainstem implants. These include attempts to exploit the polarity sensitivity of the electrically stimulated auditory system in order to extend the ranges of pitch that can be conveyed by each type of implant.
Enhancement of forward suppression begins in the ventral cochlear nucleus
Authors: Winter Ian M. , Itatani Naoya , Bleeck Stefan , Ingham Neil
Published: May 2014

A neuron's response to a sound can be suppressed by the presentation of a preceding sound (aka forward masking/forward suppression). Early studies in the auditory nerve have suggested that the amount of forward suppression was insufficient to account for behavioral data. Modeling studies have, however, suggested that forward suppression could be enhanced by coincidence detection mechanisms in the brainstem. Using a two-interval forced-choice threshold tracking algorithm, we compared forward suppression for different neuronal populations in the ventral cochlear nucleus (VCN) and the inferior colliculus of anesthetized guinea pigs. In both nuclei, onset-type neurons showed the greatest amounts of suppression (16.9–33.5 dB) and, in the VCN, these recovered with a faster time constant (14.1–19.9 ms). Neurons with sustained discharge demonstrated reduced suppression (8.9–12.1 dB) and recovery time constants of 27.2–55.6 ms. The growth of suppression, with increasing suppressor level, was compressive, but this compression was reduced in onset-type units. The threshold elevations recorded for most unit types were insufficient to account for the magnitude of forward masking as measured behaviorally; however, some units classified as onset responders demonstrated a wide dynamic range of masking, similar to that observed in human psychophysics.
Novel paradigms to investigate temporal fine structure processing
Authors: Lorenzi Christian
Published: May 2014

A wide range of evidence has been presented to support the idea that aging and cochlear hearing loss impair the neural processing of temporal fine structure (TFS) cues while sparing the processing of temporal-envelope (E) cues. However, the poorer-than-normal scores measured in tasks assessing directly TFS-processing capacities may partly result from reduced “processing efficiency.” The accuracy of neural phase locking to TFS cues may be normal, but the central auditory system may be less efficient in extracting the TFS information. This raises the need to design psychophysical tasks assessing TFS-processing capacities while controlling for or limiting the potential contribution of reduced processing efficiency. Several paradigms will be reviewed. These paradigms attempt to either: (i) cancel out the effect of efficiency (leaving only the temporal factor), (ii) assess TFS-processing capacities indirectly via E-perception tasks where efficiency is assumed to be normal for elderly or hearing-impaired listeners, or (iii) assess TFS-processing capacities indirectly via E-perception tasks designed such that impaired listeners (i.e., elderly or hearing-impaired listeners) should outperform control listeners (i.e., young normal-hearing listeners) if aging or cochlear damage cause a genuine suprathreshold deficit in TFS encoding. Good candidates in this regard are interference tasks. Pilot data will be presented and discussed.
Scattering by a cylinderical shell buried in elastic sediment
Authors: Sarkissian Angie , Dey Saikat , Houston Brian H. , Bucaro Joseph A.
Published: May 2014

Scattering results are presented for the case of cylindrical steel targets buried in elastic sediment with sound incident from the air above. The STARS3D finite element program recently extended to layered, elastic sediments is used to compute the scattering and the resulting normal displacement at the interface since the specific focus here is detection by systems which rely on monitoring the acoustic displacements or displacement-related entities at the fluid-sediment interface. Results are compared for the scattered field produced by the cylinder buried in layered elastic sediment versus in fluid sediment and for the scattered field of a buried cylindrical shell versus a buried solid cylinder. [This work was supported by ONR.]
Real-time hybrid substructuring of a physical mass-spring system coupled to a fluid-loaded analytical substructure
Authors: Botelho Rui , Christenson Richard E.
Published: May 2014

Real-time hybrid substructuring (RTHS) is a relatively new method of vibration testing that allows a coupled dynamic system to be partitioned into separate physical and numerical components or substructures. The physical and numerical substructures are interfaced together in real-time as a closed-loop hybrid experiment similar to hardware-in-the-loop (HWIL) testing, whereby the physical substructure is tested concurrently with a numerical simulation of the remaining system. This work describes uniaxial RTHS testing at the University of Connecticut Structures Research Laboratory applied to simplified fluid-loaded structural systems. These tests use a physical one degree of freedom (DOF) mass-spring system coupled to a fluid-loaded analytical substructure. One test uses a fluid-loaded plate as the analytical substructure, while another test uses a fluid-loaded cylinder. An overview of RTHS is also presented, including the details of the feedback control architecture for coupling physical and analytical substructures together using servo-hydraulic actuation with a model-based minimum-phase inverse compensation (MPIC) of the actuator dynamics. In addition, a convolution integral (CI) method for solving the fluid-loaded analytical substructures in real-time is described. Experimental results demonstrate that RTHS can accurately capture the dynamic interaction of a fluid-loaded structural system and provide physical insight into the coupled response.
Experimental research and analysis of the acoustical radiation of piezoelectric cylindrical transducers with various height-to-diameter aspect ratios
Authors: Bachand Corey , Brown David A. , Aronov Boris
Published: May 2014

Estimating the radiation characteristics of cylindrical transducers having moderate height-to-diameter aspect ratios (H/D ≈ 0.2–2) over a wide frequency range is subject to considerable error with closed-form analytical solutions. It is often the case that transducers for acoustic communication fall within this range of aspect ratios. Thus, most often numerical techniques are required to solve the acoustical radiation problem, particularly for cylinders where the surface configuration (end caps and curved walls) does not allow for separation of variables in the Helmholtz equation describing the acoustic pressure. Results of calculating radiation characteristics of finite-height cylinders based on a numerical technique developed by Kozyrev and Shenderov [Sov. Phys. Acoust. 23(6), 230–236 (1980)] are presented. Several prototype piezoelectric cylindrical transducers with aspect ratios ranging from 0.3 to 1.0 were constructed as part of the research on the radiation characteristics of finite-height cylinders. The two cases of an air-backed internal cavity with shielded end caps and of a fluid-filled internal cavity without end caps are considered. Analytical and numerical radiation estimations are compared to measured results with the prototypes, and applicability of the analytical models for different aspect ratios and wave dimensions are discussed.
Tone as a primary perceptual cue in cross-linguistic speech perception: A comparison of Cantonese and Mandarin second-language speech of English clusters
Authors: Lan Yizhou
Published: May 2014

The study examined the patterns of production and perception of L1 Cantonese and Mandarin speakers for English consonant-/l/ clusters in five consonant conditions (/ph, th, kh, f, s/) and three vowel conditions (/i, a, u/). Five Cantonese, 5 Mandarin, and 5 native English speakers were assigned to read aloud words in C[l]V and C[l]VC structure in carrier sentences. Results showed that Cantonese speakers’ /l/ was often reduced, indicated by a shorter average duration of the CV transition compared with native English speakers. However, Mandarin speakers showed a longer duration in the same measurement. Despite the identical segmental and syllable structures of these two languages in the involved words, realizations were different. Nevertheless, we found pitch patterns of Mandarin speech of L2 English featured falling tone, whereas Cantonese speakers utilized level tones. To further examine the tonal effect, we normalized the tone from the production results to a level tone at 200 Hz and presented them, together with productions with real inserted vowels in between C and /l/, to another group of Mandarin and Cantonese speakers to discriminate in an ABX paradigm. Mandarin speakers scored a significantly lower accuracy rate, indicating that their perception of duration was influenced by tone structure.
An acoustic-phonetic account of phonotactic perceptual assimilation
Authors: Chodroff Eleanor , Arnette Anthony , Ilango Samhita , Wilson Colin
Published: May 2014

Previous research has identified a coronal-to-dorsal ‘perceptual assimilation’ in which English and French listeners identify Hebrew word-initial /tl/ and /dl/ as beginning with /k/ and /g/, respectively (Hallé and Best, 2007). However, the acoustic-phonetic factors that contribute to this misperception have not been thoroughly identified, and previous results indicate that /tl/ is misperceived more often than /dl/—an asymmetry that is surprising on phonological grounds. The present study further explored this perceptual assimilation in two experiments with English listeners and Hebrew stop-liquid-vowel syllables ([t,k,d,g] × [l,ʁ] × [a,o,u]). The first experiment, which used the same stimuli as Hallé & Best, replicated previous findings, including the asymmetry between /tl/ and /dl/. The second experiment employed stimuli produced by a different native Hebrew speaker. While coronal-to-dorsal assimilation was observed, the previous /tl/-/dl/ asymmetry was not found: /dl/ was perceived as dorsal-initial somewhat more often than /tl/, suggesting that there can be no consistent phonemic or phonotactic explanation of the rate of assimilation. In support of a phonetic account, we find that misperception rates in both experiments are highly correlated (r > 0.65) with the stimulus-specific degree of anticipatory coarticulation of the lateral, as reflected in the spectral shape of the stop burst.
Speech intelligibility across native and non-native accents: Accent similarity and electrophysiological measures of word recognition
Authors: Stringer Louise , Iverson Paul
Published: May 2014

The intelligibility of accented speech in noise greatly depends on the pairing of speaker and listener, where two important factors are a listener’s familiarity with a speaker’s accent and the acoustic similarity between their accents. In this study, we present patterns of the intelligibility of standard British English, Glaswegian English and Spanish English accents for British and high and low proficiency Spanish listeners. We predict intelligibility will correlate with acoustic-phonetic similarity across accent pairings, in line with previous findings. As such, findings are expected to provide further support that accent similarity can predict patterns of accent intelligibility, even if listeners have little experience of a speaker’s accent. Electrophysiological measures relating to phonological and semantic integration stages of word recognition will also allow the investigation of the influence of accent on the time course of word recognition, which has not previously been directly compared to accent intelligibility or applied in studies of accent processing by non-native listeners. Findings will be discussed in the context of previous exploratory findings in this field, and in reference to other factors influencing accent intelligibility.
Transfer effects in perception of a familiar and unfamiliar language
Authors: Chang Charles B.
Published: May 2014

Second-language (L2) speech perception is typically worse than first-language (L1) perception, a disparity often attributed to negative transfer (interference) from the L1 of L2 listeners. The current study investigated the hypothesis that L1 transfer is not always negative, but variable depending on the nature of L1 perceptual biases. In Experiment 1, four groups of L2 English speakers whose L1s (Japanese, Korean, Mandarin, and Russian) differ in the relative informativeness of vowel-to-consonant transition cues were tested on their perception of English segments that rely crucially on these cues: final unreleased voiceless stops. In comparison to L1 English listeners, L1 Japanese, Russian, and Mandarin listeners performed significantly worse, whereas L1 Korean listeners performed significantly better. In Experiment 2, when the same groups were tested on similar Korean stimuli, L1 Russian listeners outperformed all other groups except the Korean group. These results provide evidence that L1 transfer effects are diverse and suggest that they are diverse for two reasons: variability in the information value of relevant phonetic cues in the L1, as well as variability in the degree to which linguistic expectations associated with a target L2 (or the lack thereof) predispose the listener to make effective use of these cues.
Perception of speaker sex in re-synthesized children's voices
Authors: Assmann Peter F. , Kapolowicz Michelle R. , Massey David A. , Barreda Santiago , Nearey Terrance M.
Published: May 2014

Recent studies have shown that fundamental frequency (F0) and average formant frequencies (FF) provide important cues for the perception of speaker sex. Experiments on vocoded adult voices have indicated that upward scaling of F0 and FFs increases the probability that a voice will be perceived as female while downward scaling increases the probability that the voice will be perceived as male. The present study extends these manipulations to children’s voices. Separate groups of adult listeners heard vocoded /hVd/ syllables spoken by five boys and five girls from 14 age groups (5–18 years) in four synthesis conditions using the STRAIGHT vocoder. These conditions involved swapping F0 and/or FFs to the opposite-sex average within each age group. Compared to the synthesized, unswapped originals, both the F0-swapped condition and the FF-swapped condition resulted in lower sex recognition accuracy for the older females but relatively smaller effects for males. The combined F0 + FF swapped condition produced the largest drop in performance for both sexes, consistent with findings indicating that a change in F0 or FFs alone is generally insufficient to produce a compelling conversion of speaker sex in adults. [Hillenbrand and Clark, Attention Percep. Psychophys. 71(5), 1150–1166 (2009).]