bluuebunny/crossref_metadata_2025 huggingface dataset:
Time lapse observation of phase change nano droplet after vaporization stimulated by ultrasound
Authors: Takehara Kenji , Azuma Takashi , Yoshinaka Kiyoshi , Yamaguchi Satoshi , Maezawa Miyuki , Sakuma Ichirou , Nagamune Teruyuki , Takagi Shu , Matsumoto Yoichirou
Published: November 2013

Small enough to permeate through tumor blood vessel, and can be detect by ultrasound, phase change nano droplet (PCND) have been studied as contrast agents and therapeutic sensitizer for career. To investigate performance for these purpose, we investigated physical behavior of PCND, especially a lifetime of microbubbles generated by ultrasound stimulation. To investigate bubble’s behavior after phase change, we observed a time-lapse change of bubbles population with following method. Focused transducer with a frequency of 3.3 MHz was placed in a water bath of 37 degrees. At the focal point, polyacrylamide gel including PCND was placed. Focused hydrophone was placed perpendicularly to the direction of ultrasound propagation. Two kind of ultrasound pulse wave was used; phase change pulse at the beginning and observation pulse at every 500 μs. The amplitude of scattering signal (SS) reflects the sum of scattering cross-section of bubbles. The time lapse observation of PCND after phase change showed two kinds of behavior, quick and slow decay of scattering signal from the bubbles. The unique increase of SS from the phase-changed bubbles in the monitoring phase was observed. We improved the experimental setup to measure bubble’s population properly from various directions using 1-D array transducer and will present the result.
Study of mechanism of sonoporation using lipid bilayer and surface-modified microbubble
Authors: Hirose Kodai , Azuma Takashi , Yoshinaka Kiyoshi , Sasaki Akira , Takagi Shu , Matsumoto Yoichiro
Published: November 2013

Microbubble enhanced sonoporation is one of gene therapies and expected to be safe, less invasive, and controllability of treatment area, but its induction rate is very low and its mechanism remains to be explained. The objective is to analyze the mechanism and obtain an optimal design. Because microbubble density distribution was unstable during sonication and ultrasound intensity on the cell surface was affected by distribution change through attenuation change during propagation, microbubble distribution should be controlled and localized only near the membrane to realize high reproducibility. An artificial lipid bilayer modified by biotin-avidin to bind microbubbles was used for this purpose. We have three steps: build lipid bilayer, binding with microbubbles, and introduction of sonication and observation system. We built the lipid bilayer with a diameter of 1 mm using Black Lipid Membrane method. With a capacitance measurement with impedance analyzer (NF, ZM2375), the lipid bilayer thickness was confirmed and its duration is more than an hour. Then, we introduced the sonication and observation system to the lipid bilayer, and we are observing a behavior of the lipid bilayer under irradiation of ultrasound. Afterward we will observe that of a lipid bilayer modified of microbubbles.
Optimization of acoustic parameters and nanodroplet concentration for spatially controlled, reduced energy high intensity focused ultrasound ablation
Authors: Puett Andrew C. , Phillips Linsey C. , Sheeran Paul S. , Dayton Paul A.
Published: November 2013

Background: Perfluorocarbon (PFC)-nanodroplets (ND) provide cavitation sites when vaporized to microbubbles by acoustic energy and lower the power required to ablate tissue by high intensity focused ultrasound (HIFU). However, control over ablation can be problematic. This study explored vaporization, ablation, and PFC-ND concentration in vitro to optimize the acoustic pressure (intensity) and insonation time required for spatially controlled HIFU enhancement. Methods: HIFU (continuous wave; 1MHz; 5–20 s; 2–4 MPa) was applied to albumin-acrylamide gels containing PFC-agent (1:1 mix of volatile decafluorobutane and more stable dodecafluoropentane at 105-107 ND/mL). Controlled ablation was defined as the production of cigar-shaped lesions centered at the acoustic focus. Results: Vaporization field change from “cigar” to “tadpole” began at 5×105, 2.5×106, and 1×107 ND/mL using 4, 3, and 2 MPa, respectively. The volumes of the microbubble clouds (8–200 mm3) and ablation lesions (1–135 mm3) within them were dependent on acoustic intensity, insonation time, and PFC-ND concentration. Conclusions: Ablation within microbubble clouds of predictable size, shape, and location can be generated in gels containing PFC-ND using intensities ≤650 W/cm2. Also, pressures and insonation times can be selected to achieve an ablation lesion of desired size for a given PFC-ND concentration. Demonstrating control is an important step toward developing a useful clinical tool.
Design and characterization of biocompatible perfluorocarbon nanodroplets for theragnostic application
Authors: Somaglino Lucie , Astafyeva Ksenia , Desgranges Stéphane , Polidori Ange , Contino-Pepin Christiane , Urbach Wladimir , Taulier Nicolas
Published: November 2013

We have developed stable emulsions (≥ 3 months) made of nanodroplets (nD) of perfluorocarbon (PFC) dispersed in water to serve as theragnostic agent. nD are stabilized by in house fluorinated surfactants, named FTAC, which chemical structure can be modified to tune their properties. We have characterized nD size distributions (mean diameters from 200 to 600 nm), density, adiabatic compressibility, interfacial tension. US properties of the emulsions have been investigated such as attenuation. Lastly, ultrasonic signals backscattered by nanoemulsions were studied and compared with water to extract signal to noise ratio (SNR), by emitting single negative pulses at ≈40 MHz. At similar mean/mode diameters, we showed a strong dependence in SNR values (i) with size distribution, altered by the nature of the surfactant or by a centrifugation/filtration process, (ii) with core nature, and (iii) with nD volume fraction. Besides, hydrophobic drugs such as a thalidomide derivative (with anti-angiogenic properties), have been encapsulated by addition of 10% of triacetin in the nD core. So as to study drug release from nD, a dedicated setup of US cavitation was designed. Cavitation was generated in controlled conditions using a 1 MHz focused transducer (US bursts: 12-22 MPa peak) in a thin wall container immersed in water which temperature and degassed level were kept constant. The generation of cavitation in nD solutions resulted in a strong and reproducible SNR decrease.
Front-looking and side-looking receiving beams for biosonar imaging and flight guidance
Authors: Simmons James A.
Published: November 2013

The biosonar broadcasts of big brown bats are very broadly beamed over ±60°-120°, thus ensonifying virtually all of the objects in the surrounding sonar scene. However, masking-release results indicate that off-side clutter is rejected outside of a significantly narrower beam of ±15°. Recent experiments establish that clutter interference with target imaging is prevented by sensing the lower amplitude of FM2 relative to FM1 in clutter echoes and forming poorly-focused images of the clutter. Removal of clutter from perception does not address the need to guide flight in complex surroundings bounded by clutter such as vegetation. A separate mechanism used for guidance may be located in the midbrain, where exclusively contralaterally sensitive neurons respond to target range and direction, the ingredients for following the flow of surrounding objects as they slide past the flying bat. A review of neurophysiological results from different laboratories suggests that the big brown bat’s biosonar system may contain different receiver pathways—a forward-looking system for target imaging and classification, and a side-looking system for following the surrounding clutter. [Work supported by ONR and NSF.]
Improving direction-sensing by multibeam sonar
Authors: Llort-Pujol Gerard , Foote Kenneth G. , Sintes Christophe
Published: November 2013

The complexity of multibeam sonar systems makes their beamforming susceptible to amplitude and phase distortion, e.g., due to environmental changes. A form of calibration is usually performed in situ over a flat area to ensure flatness in the resulting sonar image. However, lack of detailed knowledge of individual channel performance prevents application of an amplitude-weighting function such as the Blackman or Hamming type, which could otherwise be used to reduce the impact of sidelobes without damaging signal quality. Two radically different solutions are proposed: application of the Vernier principle [G. Llort-Pujol, Oceans 2006 MTS/IEEE Conf. Proc. (Quebec City, Canada, 2008); C. Sintes et al., Oceans 2011 MTS/IEEE Conf. Proc. (Waikoloa, HI, 2011)] to interferometry performed at low grazing angles, and performance of a standard-target calibration [K. G. Foote et al., J. Acoust. Soc. Am. 117, 2013 (2005)] to measure the two-way sensitivity of individual channels directly. The two methods, which are also applicable to sidescan sonar, are elaborated.
Interaction design and the active experience of music
Authors: Wessel David
Published: November 2013

Music search engines, play list generators, streaming audio, and portable players have taken much of the focus of music technology. The emphasis is on delivery and experiencing music is by playback, playback while jogging or while working about the house, and sadly even while studying. In this talk in the hope of providing an antidote I will examine the role of bodily action in the experience of music and the importance of human computer interaction design in the development of computationally based musical instruments. Central are gestural interfaces and their mapping to musical material. Special emphasis will be given to designing for expression, for exploration and discovery, and to a musical practice that involves a coordinated balance of software development and daily bodily engagement with one's instrument.
Drawn to sound: An audio visual musical instrument using custom electronics and magnetometer
Authors: Granzow John , Choi Hongchan
Published: November 2013

Drawings are amplified through a resonant surface and transmitted via microphone to custom software hosted on an embedded linux computer. An HMC-5883L magnetometer is used to modulate the signal according to the position of the pencil (equipped with magnetic sleeve). 3D vectors are derived from the magnetometer using a custom Arduino library. We project this vector into a 2D plane to get magnitude or distance between the sensor and the magnetized pencil as well as the heading angle. This implementation gives us 2D polar coordinates such that the position of the pencil can be used to vary the audio output. The transformation of the raw drawing sound is excited with proximity to the magnetometer due to the sensors exponentially increasing sensitivity to the magnetic field. Resulting drawings often contain both visually motivated marks as well as gestures that are made for sound such as dark scribbled regions where a desired timbre or pitch shift is repeated throughout a performance. This presentation will discuss hardware design, the implementation of our custom software and circuitry, how these components combine for a compelling performance platform as well as areas where we seek improvement.
Towards a bendable circuit model of the Casio SK-1 keyboard
Authors: Werner Kurt J.
Published: November 2013

The Casio SK-1 keyboard was introduced in 1985 and synthesizes sampled and built-in sounds via pulse-code modulation and additive ("harmonic") synthesis. Initially important as one of the first home keyboards with sampling capabilities, the SK-1 has become one of the most popular instruments for circuit bending, the process of creatively modifying or augmenting sound-producing electronic devices. I create a parameterized component-level software model of the analog circuitry of the Casio SK-1, with applications to archiving and preserving its historic sound, expanding its basic behavior through circuit-bent modifications and extensions, and providing circuit benders with a resource for informed bending. Throughout, special attention is paid to creating models in terms of the circuit's component values. The SK-1's Percussion, Bass, and Chord Filters are modeled and analyzed in continuous-time as transfer functions and discretized via the bilinear transform. The non-linear (including diodes and transistors) Envelope/Pitch Mixing Circuit and Melody Filter are analyzed with linearizing simplifications to elucidate design intent, and modeled as ordinary differential equations to capture their behavior accurately. A review of techniques for the numerical solution of ordinary differential equations follows. A model of the internal speaker's impulse response and estimated static non-linearity rounds out the project.
Use of a large microphone array to identify noise sources during a rocket engine test firing and a rocket launch
Authors: Panda Jayanta , Mosher Robert N. , Porter Barry J.
Published: November 2013

A 70 microphone, 10 ft×10 ft, microphone phased array was built for use in the harsh environment of rocket launches. The array was setup at NASA Wallops launch pad 0A during a static test firing of Orbital Sciences’ Antares engines, and again during the first launch of Antares vehicle. It was placed 400 ft away from the pad, and was hoisted on a scissor lift 40 ft above ground. The data sets provided unprecedented insights into rocket noise sources. The duct exit was found to be the primary source during the static test firing; the large amount of water injected beneath the nozzle exit quenched all other sources. The noise maps during launch were found to be time-dependent. As the engines came to full power and became louder, the primary source switched from the duct inlet to the duct exit. Further elevation of the vehicle caused spilling of the hot plume, resulting in a distributed noise map covering most of the pad. As the entire plume emerged from the duct, and the on-deck water system came to full power, the plume itself became the loudest noise source. These noise maps will help to improve the sound suppression system for future launches.
Scale model thruster acoustic measurement results
Authors: Vargas Magda B. , Kenny Robert J.
Published: November 2013

The Space Launch System (SLS) Scale Model Acoustic Test (SMAT) is a 5% scale representation of the SLS vehicle, mobile launcher, tower, and launch pad trench. The SLS launch propulsion system will be comprised of the Rocket Assisted Take-Off (RATO) motors representing the solid boosters and four Gas Hydrogen (GH2) thrusters representing the core engines. The GH2 thrusters were tested in a horizontal configuration in order to characterize their performance. In phase 1, a single thruster was fired to determine the engine performance parameters necessary for scaling a single engine. A cluster configuration, consisting of the four thrusters, was tested in phase 2 to integrate the system and determine their combined performance. Acoustic and overpressure data was collected during both test phases in order to characterize the system’s acoustic performance. The results from the single thruster and 4-thuster system are discussed and compared.
Numerical study on acoustic generation of a supersonic jet impinging to deflectors
Authors: Tsutsumi Seiji , Takaki Ryoji , Okamoto Koji , Teramoto Susumu
Published: November 2013

Acoustic wave generated from a M = 1.8 ideally expanded jet impinging on flame deflectors is investigated numerically in order to obtain the knowledge of flame deflector design to mitigate the acoustic loading on launch systems and payloads. Mechanism of acoustic wave generated from a 45-degree-inclined flat plate placed 5D downstream from the nozzle exit is analyzed first, and it is revealed that source of the acoustic wave is located where shock waves is formed due to the jet impingement. In this study, effect of the deflector shape will be discussed for better understanding the acoustic generation mechanism.
Towards jet acoustic prediction within the Launch Ascent and Vehicle Aerodynamics framework
Authors: Housman Jeffrey A. , Brehm Christoph , Kiris Cetin
Published: November 2013

Understanding the acoustic environment generated during lift-off is critical for successfully designing new space vehicles. In order for modeling and simulation tools to effectively assist in the development of the vehicles, validation must be performed on simplified model problems. In this paper, time-accurate implicit large eddy and detached eddy simulations coupled with a linear acoustic propagation method are applied to a Mach 1.8 perfectly expanded jet impinging on a flat plate at 45 degrees. The Launch Ascent and Vehicle Aerodynamics (LAVA) code used to simulate this problem is a high-fidelity unsteady simulation tool for modeling fluid dynamics, conjugate heat transfer, and acoustics. A detailed description of the linear acoustic propagation tool is provided. The narrow band far-field sound pressure levels predicted using LAVA are compared to existing experimental data. POD and spectral methods are applied to analyze the noise sources due to coherent flow structures and jet impingement. Grid and time-step sensitivity studies are performed to assess the spatial and temporal requirements for accurate jet acoustic simulation. Sensitivity of the predicted far-field sound pressure levels to position of the acoustic propagation surface is also assessed.
Methods for estimating acoustic intensity in rocket noise fields
Authors: Thomas Derek C. , Christensen Benjamin Y. , Gee Kent L.
Published: November 2013

The acoustic field produced by launch vehicles is difficult to measure and characterize. Acoustic intensity measurements provide more information per measurement location than pressure measurements and are therefore interesting for the characterization of rocket noise fields. The extreme environment associated with a rocket requires a robust intensity probe while the large size of the source and the high-amplitude, highly nonlinear behavior of the system produce a signal with significant low and high frequency components. Thus, the probe must also provide accurate results over a large frequency band. The bandwidth limitations of the standard method for estimating acoustic intensity, the p-p finite difference method, motivated the development of an alternative method for intensity estimation. The new phase and amplitude gradient estimation (PAGE) method will be presented and compared to the standard p-p method. Specific features of the rocket noise field that can be leveraged to improve the bandwidth of the intensity estimates will also be discussed.
Acoustic intensity estimates from a solid rocket motor test firing
Authors: Christensen Benjamin , Thomas Derek C. , Gee Kent L.
Published: November 2013

Acoustic measurements of a static GEM-60 solid motor test firing were taken as part of a continuing effort to characterize the aeroacoustic source regions and noise environment around launch vehicles. Multiple 2D intensity probes, consisting of four coplanar microphones, were used in the measurement. Two intensity estimation techniques have been applied to the data: the finite difference p-p method, and the new phase and amplitude gradient estimation (PAGE) method. We will present and compare results from both methods and compare to measurements made at past test firings. It appears that the PAGE method for estimating acoustic intensity provides usable results over a larger frequency bandwidth.
A Monte Carlo approach to determining marine mammal exposure risk to long term marine piling operations
Authors: Lepper Paul A. , Robinson Stephen P. , Theobald Pete D. , Pangerc Tanja
Published: November 2013

The expansion of offshore renewable developments, primarily offshore wind, has led to widespread use of large scale percussive piling for foundation construction. In UK waters alone, over 900 foundations installed up to 2013, mostly mono-piles with extensive up-scaling of developments planned for the next decade. Pile diameters range from a few meters to greater than 6 m and penetration depths of 20–30 m. These piles are typically percussively driven with several thousand hammer strikes over periods of several hours with individual strike hammer energies in excess of 1900 kJ occasionally used and reported per strike underwater Sound Exposure Level source levels of 215 dB re 1 μPa2s-m2. Potential exists for injury to occur from cumulative sound exposure to repetitive but lower level signals at greater range. If simple receptor behaviors are assumed (static, fleeing, etc.) exposure over time to an entire pile construction sequence can be estimated. These models have been extended using a Monte Carlo approach to model long term, entire wind farm construction scenarios with repetitive foundation construction periods of 24–36 h. The statistical distribution of exposure risk is modeled as well as analysis of the sensitivity of behavioral responses to potential impact effects such as habitat exclusion.
Noise mitigation systems (NMS) for reducing pile driving noise: Experiences with the “big bubble curtain” relating to noise reduction
Authors: Bellmann Michael A. , Remmers Patrick
Published: November 2013

For the offshore wind farm Borkum West II in the German North Sea the Noise Mitigation System (NMS) “Big Bubble Curtain” was used during pile driving activities. Within this project systematically variations of different influencing factors on noise reductions such as air volume, nozzle hose sizes, distance of nozzle hoses, etc., were investigated. Additionally the “Big Bubble Curtain” is currently in use for different other OWF in the German North Sea. Therefore, the “Big Bubble Curtain—BBC” is at the moment one of the most investigated NMS under offshore condition. Within this presentation, experiences and results of the above listed projects will be shown and discussed.
Efficient application of encapsulated bubbles and foam elements to mitigate offshore piling noise
Authors: Elmer Karl-Heinz
Published: November 2013

The very high noise levels of offshore piling noise during the installation of offshore wind converters are dangerous to marine life like harbor porpoises and fishes. Encapsulated bubbles and foam elements are successfully used to reduce the very high noise levels. There are different physical effects such as impedance mismatch, resonance and scattering effects and material damping effects that are responsible to the measured noise reduction between about 10 dB (SEL) and 23 dB (SEL). The radiation of underwater noise from the pile surface, the propagation and the reflections of the radiated waves are investigated together with the influence of encapsulated bubbles and foam elements in the near field of the pile. Only a very small part of the impact energy is radiated directly from the pile into the surrounding water. Most of the hammer energy is driven into the ground. A small part from this is radiated indirectly from the ground into the water. The efficiency of encapsulated bubbles and foam elements in underwater noise mitigation is investigated by theoretical studies, laboratory measurements, and by offshore measurements with different elements and combinations.
Dependence of resonance frequencies and attenuation for large encapsulated bubbles on bubble wall thickness and bubble fill-material
Authors: Enenstein Gregory , Wilson Preston S. , Lee Kevin M.
Published: November 2013

Arrays of large encapsulated bubbles are currently under development for the purpose abating low-frequency anthropogenic underwater noise from various sources including marine pile driving and oil and gas exploration and production. An existing predictive model [Church, J. Acoust. Soc. Am. 97, 1510–1521 (1995)], which was originally intended to describe propagation through suspensions of microbubbles used as ultrasound contrast agents, was previously found to be in good agreement with resonance frequency and attenuation measurements using large encapsulated with radii on the order of 10 cm [Lee et al., J. Acoust. Soc. Am 132, 2039 (2012); Lee and Wilson, Proceedings of Meetings on Acoustics 19, 075048 (2013)]. For the current study, both laboratory and lake experiments were performed on large encapsulated bubbles to investigate the dependence of the bubbles’ resonance frequencies and attenuation on the bubble wall thickness. Additionally, laboratory measurements were made to investigate the effects on encapsulated bubble resonance frequencies and damping using bubble fill-materials other than air, and a lake experiment was then performed to relate these effects on the damping to the attenuation provided by arrays of such bubbles. [Work supported by AdBm Technologies.]
Acoustic measurements and modeling of air-filled, underwater resonator cavities
Authors: Tseng Laura , Lee Kevin M. , Wilson Preston S. , Wochner Mark S.
Published: November 2013

This paper investigates the near-resonance acoustical properties of submerged air-filled resonators intended for use in an underwater noise abatement system. These resonators are a potential alternative to encapsulated bubbles. The resonators are similar to Helmholtz resonators in shape and design, but without a neck, consisting of underwater inverted air-filled cavities with rigid walls. A finite element model was developed to investigate the acoustic behavior of the resonators near their resonance frequencies, and based on the results of the model, physical realizations of the resonators were designed and fabricated for testing. Experiments were performed with the resonators in a closed water-filled tank operated in the long wavelength limit [J. Acoust. Soc. Am. 132, 2039 (2012)], where their resonance frequencies and Q-factors were measured using the technique described by Leighton et al., [J. Acoust. Soc. Am. 112, 1366–1376 (2002)]. Comparison between the results from the measurements and modeling will be discussed. [Work supported by Shell Global Solutions.]
Physical models and improvement of bubble curtain for the suppression of underwater noise from a pile drive
Authors: Sutin Alexander , Salloum Hady
Published: November 2013

Man-made sounds in ocean and inland water environments become biologically significant when they affect the ability of animals and fish to survive and reproduce. Extremely strong sounds produced by pile driving can highly exceed the environmental safety limits and application of bubble curtain is one of the most effective methods for sound suppression. We present several physical models explaining sound suppression by bubble curtain and discuss the methods of improving bubble curtain efficiency. The physical models of sound suppression by a bubble curtain include: (a) Estimation of bubble curtain impedance leading to decreasing of the pile drive acoustic coupling with surrounding bubbly water and (b) theoretical model for the estimation of sound attenuation by resonance bubbles. The developed models were analyzed for the optimization of the pile drive sound suppression. Several methods for generating a bubble curtain with small bubbles and bubbles with varied sizes are considered. We also suggest a way for improving the efficiency of bubble curtains by increasing the lifetime of the bubbles using bubble coating. Coated micro bubbles are widely used as ultrasound contrast agents in cardiology. One of the simplest ways for micro bubble coating is the passing of bubbles through oil.
Effect of sound duration on loudness estimates of increasing and decreasing intensity sounds
Authors: Ponsot Emmanuel , Verneil Anne-Laure , Susini Patrick
Published: November 2013

The influence of sound duration on global loudness of non-stationary stimuli was investigated. Loudness of 2 and 6-s increasing and decreasing intensity sounds with different ranges of intensity-variation was assessed using a magnitude estimation procedure. Results once again uphold the existence of a loudness difference between the two patterns: while they only differ in their temporal profile, increasing sounds were perceived louder than decreasing sounds. In addition, global loudness estimates were increased with duration for the two types of sounds, and a small but significant interaction occurred between type and duration. A contrast analysis revealed that while global loudness of increasing and decreasing sounds raised with duration in a similar way in the case of low and moderate intensities (below 75 dB SPL), global loudness was significantly more affected by duration with increasing than with decreasing intensity profiles for high-intensity stimuli. This result suggests the existence of an underlying memory process combined with a “peak-end rule” as being responsible for the loudness asymmetry typically observed between the two types of intensity-pattern being judged [Susini et al. (2010). “End level bias on direct loudness ratings of increasing sounds” J. Acoust. Soc. Am. EL 128(4), 163–168].
Finite element model of feed-forward/feed-backward amplification in the mouse cochlea
Authors: Soons Joris , Puria Sunil , Steele Charles R.
Published: November 2013

Thousands of hair cells in the organ of Corti, situated along the basilar membrane (BM), detect displacements due to sound input. For low input sounds, these displacements are amplified by active outer hair cells (OHCs). A proposed theory is the feed-forward/feed-backward mechanism for the OHC amplification where an expanding hair cell gives a forward push through the Deiters Cells and a backward pull on the BM through the Phalangeal process. Previously this was implemented mathematically using WKB theory (Yoon et al. 2011, Biophys. J.). In the present work, we explicitly modeled this as a Y-shaped arrangement of the OHC-DeitersCell-PhallangealProcess to form a building block using beam elements in a finite element formulation. These Y-shaped blocks were chained together to construct a single-row organ-of-Corti model from the base to apex, coupled to the BM and scalae fluid, of a mouse cochlea. The OHC force is proportional to the shear on the BM. For a 10 kHz stapes input tone, the passive BM reaches a peak gain of about 26 dB. For the active case the BM gain increases to 58 dB and shifts apically by about 0.6 mm. These results are consistent with physiological measurements in several other living animals.
Should the acceptable noise level be considered to be an acceptable noise range?
Authors: Brännström Jonas , Holm Lucas , Kastberg Tobias , Olsen Steen J.
Published: November 2013

The acceptable noise level (ANL) test is used to quantify the amount of competing background noise (BNL) that a listener is willing to accept when listening to speech at the most comfortable level (MCL). ANL is calculated by subtracting the BNL from the MCL. Most studies show large intersubject ANL variability and a few also demonstrate large intrasubject variability. Very few predictor variables for ANL have been identified and it has been proposed that the ANL depends on an inherent characteristic of the listener. However, some of the variability seems to depend on poor precision of the ANL test. After removing the effect of poor precision, some variability still remains. One possible explanation for these findings may be that the ANL is not a single level but a range of levels. Using recent data, this presentation examines the notion of an acceptable noise range.
Effects of speakers' language background on speech perception in adults
Authors: Dame Mark A. , Patra Harisadhan , Vaz Petula C. , Ray Biswajit
Published: November 2013

With an increasingly changing sociolinguistic environment in the U.S., clinicians are challenged to accurately evaluate individuals’ speech perception under realistic everyday listening conditions. This study investigated how contextual linguistic information, speakers’ language background, speech-rate, and background noise individually and interactively affect listeners’ ability to recognize sentences. Ten normal-hearing American English native speakers, aged 20–22 years were recruited as listeners. Eight normal-hearing native speakers of four different languages (American English, Chinese-Mandarin, German, and Spanish) were recruited as speakers. These speakers read 120 sentences, 60 high-predictability and 60 low-predictability sentences from the revised Speech in Noise test (Bradlow and Alexander, 2007), which served as test stimuli. The listeners reported the target word of each sentence presented either in quiet or in multitalker babble. Results revealed that noise, high speech-rate, and lack of contextual cues could have significant adverse affects on listeners’ test scores. Speakers’ language background also had significant effects on listeners’ performance. Specifically, listeners had the most difficulty in perceiving the Chinese-Mandarin speakers, followed by the Spanish, and German speakers; more so in multitalker babble than in quiet. Further studies are warranted since results may have implications for audiology diagnosis and rehabilitation to address effective everyday communication.
Training Mandarin-speaking amusics to recognize pitch direction: Pathway to treat musical disorders in congenital amusia?
Authors: Liu Fang , Jiang Cunmei , Francart Tom , Chan Alice H. , Wong Patrick C.
Published: November 2013

Congenital amusia is a lifelong disorder of musical perception and production that has been hypothesized as due to impaired pitch direction recognition. This study investigated whether amusics could be trained to identify pitch direction in speech and music, and if so, whether enhanced pitch direction recognition would benefit musical processing in amusia. Eighteen Mandarin-speaking amusics and 18 matched controls were evaluated using the Montreal Battery of Evaluation of Amusia (Peretz et al., 2003) and tested on two psychophysical pitch threshold tasks for identification of pitch direction in the Mandarin syllable /ma/ and its piano tone analog. Subsequently, nine of the eighteen amusics undertook a 10-session training program on pitch direction identification in /ma/ and piano tone. Compared with those untrained, trained amusics demonstrated significantly improved thresholds for pitch direction identification in speech syllables [pretest: 2.92 (4.63) semitones; posttest: 0.16 (0.06)], and marginally significant improvement in pitch direction identification thresholds for piano tones [pretest: 5.20 (4.56); posttest: 0.89 (1.46)]. These findings suggest that pitch sensitivity of individuals with congenital amusia could be improved through auditory training, providing evidence for neural plasticity in the amusic brain, which may lead the way to other rehabilitative programs for treating this musical disorder.
Neuromagnetic beta-band oscillation for rhythmic processing induced by subjectively accented structure
Authors: Fujioka Takako , Trainor Laurel J. , Ross Bernhard
Published: November 2013

Musical rhythm facilitates synchronized body movements and schema-based, predictive timing perception. Our previous magnetoencephalography (MEG) study demonstrated that beta-band (~20 Hz) activity in bilateral auditory cortices shows synchronized modulation that predicts the time point of the next beat (Fujioka et al. 2009, 2012). Furthermore, after finger tapping to a different musical meter such as a march or waltz (every 2nd or 3rd beat), the broadband evoked response from auditory cortex differentiates the metric conditions (Fujioka et al., 2010). Here we examined how beta-band activity indexed subjective metrical perception during listening to unaccented beats (1) after listening to acoustically accented beats, and (2) after finger tapping with either the left or right index finger. The auditory cortices showed beat-synchronized modulation in line with the previous studies in both march and waltz conditions. However, distinction between down-beat and up-beat positions was stronger in march than in waltz condition, with symmetrical activities in the left and right auditory cortices. This contrast between the two metric conditions was stronger in the side contralateral to the tapping finger in the tapping condition. This suggests that contribution of auditory cortices to metric processing depends on both its timing structure and rhythmic movement in the contralateral hemisphere.
A comparison of perfectly matched layers and infinite elements for exterior Helmholtz problems
Authors: Bunting Gregory , Prakash Arun , Walsh Timothy
Published: November 2013

Perfectly matched layers and infinite elements are commonly used for finite element simulations of acoustic waves on unbounded domains. Both involve a volumetric discretization around the periphery of an acoustic mesh, which itself surrounds a structure or domain of interest. Infinite elements have been a popular choice for these problems since the 1970s. Perfectly matched layers are a more recent technology that is gaining popularity due to ease of implementation and effectiveness as an absorbing boundary condition. In this study, we present massively parallel implementations of these two techniques, and compare their performance on a set of representative structural-acoustic problems on exterior domains. We compare the ability of these methods to absorb acoustic waves on ellipsoidal domains with waves of relatively high oblique angles of incidence. We also examine the conditioning of the linear systems generated by the two techniques by examining the number of Krylov-iterations needed for convergence to a fixed solver tolerance. [Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL850000.]
Analytical scattering method of flexural waves considering the evanescent field in a thin plate
Authors: Cho Sungjin , Park Junhong
Published: November 2013

This paper presents a theoretical solution on analyzing the scattering behaviors of the flexural waves by a circular obstacle medium having different material properties. In deriving the exact solution, the evanescent field together with the scattered field is considered. The modified Bessel function of the second kind is used for the evanescent field. As the evanescent wave is exponentially decaying in all directions near the edge of a circular obstacle medium when the mass density and critical angle are discontinuous, the scattering pattern without evanescent field is difficult to analyze the wave scattering phenomenon near the boundary layer. The resulting equations are solved using symbolic calculation of software Matlab. The dependence of the scattering behaviors on the mechanical properties of the inner medium is investigated. The influence of the evanescent field on the scattering is also investigated in various configurations. The result shows that the scattering pattern has a strong dependence on the evanescent field in near field of a circular obstacle.
Measurement of formants in synthetic vowels
Authors: Shadle Christine H. , Nam Hosung , Whalen D. H.
Published: November 2013

The measurement of formant frequencies of vowels is among the most common measurements in speech studies, but is known to be biased by the particular fundamental frequency (F0) exciting the formants, and to be inaccurate for formants close together or for speakers using a high F0. To allow a comparison across multiple measurement techniques, vowels were synthesized using the Klatt synthesizer with known formant values. The synthetic vowels were constructed with five different F1 values and nine different F0 values; formant bandwidths, and higher formant frequencies, were constant. The F0s varied in such a way that the most intense harmonic in F1 or F2 either matched the center frequency or deviated in the range of 3–87 Hz. Manual measurements by four subjects were compared to automatic measures using the LPC Burg algorithm, LP closed-phase covariance, and spectra smoothed cepstrally or by averaging repeated DFT's. Formants were also measured from pruned reassigned spectrograms. Error patterns differ among the methods, but most tracked the frequency of the most intense harmonic; the smallest errors occur with closed-phase covariance and reassigned spectrogram. Implications for such measures on vowels in isolated words of real speech are discussed. [Work supported by NIH-NIDCD grant DC-002717.]
Automated assessment of English fundamental frequency contours for non-native speakers from China and India
Authors: Evanini Keelan , Wang Xinhao
Published: November 2013

This study investigates the F0 contours produced by non-native speakers of English from two different countries. Speakers from China (N = 202; L1 Mandarin) and India (N = 230; multiple L1s) read a paragraph out loud in the context of an assessment of non-native English speaking proficiency; in addition, a control set of native speakers (N = 85) read the same paragraph. The words and phonemes in all of the responses were provided with time stamps using forced alignment with the prompt text, and mean normalized F0 values were extracted for each word from each speaker. A model F0 template for the paragraph was generated by taking the mean word-level F0 value across all native speakers, and the correlation between the word-level F0 contour and this template was calculated for each non-native speaker (as in Schwanenflugel et al. 2004). This correlation was used as a feature for assessing F0 contours and was correlated with expert human scores of English proficiency. The results demonstrated that the feature performed somewhat better for the speakers from India (r = 0.390) than the speakers from China (r = 0.326). Furthermore, the correlations improved when function words were removed from the analysis and only content words were considered (r = 0.396 and r = 0.346).
Intensity slopes as robust measure for distinguishing glottalic vs pulmonic stop initiation
Authors: Grawunder Sven
Published: November 2013

A novel cross-linguistically robust measure is introduced for the linguistically relevant distinction of pulmonic vs glottalic (ejective) stops. We propose to parametrize the abruptness of the following vowel onset by using intensity slope (RMS-trajectory) at the voicing onset. This measure was previously discussed only for voicing distinction of pulmonic stops (Harrington, 2012). The dependencies on vowel quality of the following vowel, voice onset time (VOT), phonetic prominence and speaking rate are investigated on a small-scale sample of two speakers from Avar (Nakh-Dagestanian), Ingush (Nakh-Dagestanian), and Georgian (Kartvelian). The results demonstrate robust significant differences of intensity slopes between pulmonic and glottalic stops, the latter showing the steepest slopes/the most abrupt onsets. In some cases of prevoiced stops, the intensity slopes allow even a tripartite distinction of (pre-)voiced, voiceless (aspirated), and ejective stops. However, in order to countervail the influence of vowel specific onset characteristics (e.g., degree of lip rounding) or the influence of VOT, the sample must be controlled for vowel quality and place of articulation. And, since higher speaking rates and less prominent syllables involve higher rates of laryngealized (creaky) vowel onsets, a breakdown of the abruptness distinction is observed under these conditions.
An online investigation of compensation for coarticulation in Mandarin learners of English
Authors: Li David , Kaiser Elsi
Published: November 2013

Phonological variation can cause lexical ambiguity: The word “run” may sound like “rum” in sentences like “A quick run picks you up” (Gaskell and Marslen-Wilson, 2001) because /n/ is assimilated to /m/ due to the influence of /p/. Previous studies have shown that listeners compensate for coarticulation, perceiving acoustically identical sounds differently in different contexts (e.g., Mann, 1980). We investigated whether native Mandarin speakers with English as a second language (L2) compensate for assimilation in the same manner/to the same extent as native English speakers (L1). Given that there are no Mandarin words with the nasal coda [m], do Mandarin learners of English compensate for phonological variation not present in their L1? We conducted a visual-world eye-tracking study—using English stimuli—to investigate compensation-for-assimilation in L1 English and L1 Mandarin speakers. Identical acoustic sequences were embedded in carrier sentences with fast vs slow speech rates to test interpretation of potentially ambiguous words (cf. rum/run) by L1 and L2 speakers. Eye-movements reveal real-time differences in how L1 and L2 speakers interpret coarticulated speech, with L1 speakers showing signs of rapid compensatory processes. We also discuss how listeners’ interpretation is influenced by other acoustic cues in coarticulated speech.
Effect of consonantal place of articulation on the perception of phonetic voicing in plosives
Authors: Kharlamov Viktor , Loukianova Anna
Published: November 2013

For plosive consonants, production of phonetic voicing often varies across consonantal places of articulation. Anterior stops (e.g., /b/, /d/) tend to show more glottal pulsing compared to the plosives produced towards the back of the oral cavity (e.g., /g/), which is traditionally attributed to the smaller volume of air passing through the glottis during the closure stage of posterior stops. The current work demonstrates that a similar effect of consonantal place of articulation also exists in perception. Results of a series of identification experiments show that English listeners (n = 60) are more sensitive to glottal pulsing in word-final dorsals than labials or coronals. The effect is especially robust when, within each experimental block, listeners are exposed to variability in consonantal place of articulation (i.e., when labial, coronal, and dorsal plosives are blocked together) but not to variability in phonetic vowel duration (i.e., when a given block contains only short or long vowels). This suggests that glottal pulsing is more perceptually salient in posterior plosives, for which voicing is less expected in production, and that the sensitivity to voicing in dorsals is stronger when listeners can do an online comparison of voicing cues across different places of articulation.
Comprehending speech at artificially induced rates
Authors: da Silva Lucia , Barbosa Adriano V. , Vatikiotis-Bateson Eric
Published: November 2013

This study confirms and extends Fairbanks, Guttman and Miron’s study (1957), where comprehension of time-compressed (2:1), recorded speech was improved when played back twice. Specifically, we examine the perception of pitch corrected and non-pitch corrected compressed speech when presented twice in succession and twice with delays of minutes between stimulus presentations. Additionally, we investigate whether visual speech information aids or hinders comprehension by comparing fast rate effects when presented acoustically and audiovisually. A motivation for this study is the increasing dependency on web-based multimedia recordings for knowledge transfer.