bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactive room auralization of sound sources with exchangeable directivities
Authors: Aspöck Lukas , Vorländer Michael
Published: October 2015

Although established measurement methods and simulation models for source directivities are available, there is a lack of tools to directly experience the audible effects of virtual sound sources in different conditions. Only an auralization in connection with psychoacoustic experiments can answer questions regarding the required solution and quality of sound source directivities. This paper presents a real-time simulation engine based on geometrical acoustics which accounts for both source directivities and the room acoustics of the environment. A hybrid simulation model is applied combining an image source model and a ray tracing algorithm to generate a binaural room impulse response, which is then convolved with an anechoic sound file (e.g., of a musical instrument). A convenient user interface is introduced by integrating the simulation engine into the 3D modeling program SketchUp. This makes it possible to easily position virtual sound sources and select various source directivities inside a modifiable room model. The listener receives immediate perceptual feedback and is able to examine the effects of varying virtual sound source locations and source directivities in different room acoustic environments.
The soundscape of worship
Authors: Siebein Gary W. , Siebein Kara A.
Published: October 2015

Soundscape theory provides insights into the architectural acoustic design of religious buildings that demonstrate how acoustical issues can be integrated within worship spaces of the 21st century. Eliade (1959) conceives of worship spaces as a sacred enclosure where communication with the God is made. The spaces must have a door to the world above, by which the God can descend to earth and man can symbolically ascend to heaven. Sometimes this is manifest as one confronts his or her God alone, in silence; sometimes, it is manifest in the joyous singing and praying or sad wailing of the entire community joined in corporate celebration or solemnity during momentous events. If one pays careful attention to the group involved with the design of a facility, they can tailor the architectural, acoustical, and electronic systems design to provide a unique acoustical identity that expresses the individual aspirations of the particular church. The technical tools for measurement and assessment of existing conditions, modeling of proposed changes, and simulating the anticipated results so evaluations can be made while the design is still in a computer are readily available to allow consultants to develop acoustical aspects of worship spaces that are unique for each project.
Fibrin-targeted echogenic liposomes for localized ablation of thrombi with histotripsy pulses
Authors: Bader Kenneth B. , Haworth Kevin J. , Maxwell Adam D. , Peng Tao , McPherson David D. , Holland Christy K.
Published: October 2015

Deep vein thrombosis is a debilitating condition that can result in pulmonary embolism, or post-thrombotic syndrome. Clot lysis can be initiated with histotripsy, a novel form of therapeutic ultrasound that uses the mechanical action of microbubble clouds to ablate tissue. Thrombolytic-loaded echogenic liposomes (t-ELIP) have fibrin targeting capabilities and also entrain gas microbubbles that act as cavitation nuclei. We hypothesize that t-ELIP can nucleate microbubble cloud formation near the clot, providing targeted ablation. Highly retracted porcine whole blood clots were exposed to either histotripsy pulses alone, or histotripsy pulses and t-ELIP between peak negative pressures of 7.5 MPa and 20 MPa. Thrombolytic efficacy was assessed via clot mass before and after treatment. Microbubble cloud activity was monitored with passive cavitation imaging (PCI) during histotripsy exposure. For a given pressure, no significant differences were observed in the thrombolytic efficacy with or without t-ELIP. The dimensions of the bubble cloud, assessed on the PCIs, were significantly reduced in the presence of t-ELIP (p < 0.05). Thus, the presence of t-ELIP confines the business end of the bubble activity to the clot. Overall, the combination of histotripsy and t-ELIP is a promising mechanism for targeted ablation of thrombi resistant to thrombolytic drugs.
Acoustic calibration in mass production
Authors: Logan Roger M.
Published: October 2015

While calibrations in high volume settings are bound by the same laws of nature that govern laboratory grade measurements, the laws of economics bring their own set of challenges to the bench. This presentation will explore the art and science of making efficient acoustic measurements in small air-filled tanks using mostly COTS equipment.
Investigation and correction for the calibration error of using two-microphone impedance tube method on low absorption materials
Authors: Zhang Yi , Wang Tongan , Lynch Kristopher
Published: October 2015

The two-microphone impedance tube method has been widely used for determining the sound absorption coefficients of materials. In this method, a calibration procedure is performed to correct the amplitude and phase mismatch of the two microphones, through repeated measurement of a specimen with the two channels interchanged. Both ASTM E1050-12 and ISO 10534-2 suggest the use of a highly absorptive material as the calibration specimen and the calibration, once complete, is valid for all successive measurements. When following the Standards, however, test materials of low absorption capability exhibited a pattern of peaks and dips in the absorption coefficient curve at certain frequencies, which are obviously not a part of the material’s own behavior. This paper will discuss the cause of these peaks and dips and also suggest a simple solution to the issue. Using the new method, one is able to obtain smooth absorption coefficient curves for low absorption test materials just as expected.
Acoustic and sediment data in the southern New England Bight
Authors: Gopu Chitanya , Potty Gopu R. , Miller James H. , Lynch James F.
Published: October 2015

This study provides a review of the acoustic and ocean bottom sediment data collected during the Shelf Break Primer experiment conducted in 1996. The location of the experiment was in the southern New England Continental Shelf called the “New England Mud Patch.” The mud patch is a 13,000 square kilometer area covered by fine-grained sediment. Previous surveys in this area have estimated the thickness of this fine grained sediment deposit to be as much as 13 m. This layer of sediment rests on a reflector that is geomorphically similar to and continuous with the Holocene transgressive sand sheet, which is exposed on the shelf to the west of this area. This fine-grained sediment layer, which is oriented in an east-west direction seaward of the 55–65 m isobath, contains more than 30% silt and clay. During the Primer experiment, broadband acoustic sources were deployed in the western side of the “mud patch” along and across the continental shelf. The acoustic data collected on a vertical line array will be analyzed. Sediment data from gravity cores from the area will also be presented. [Work sponsored by Office of Naval Research, code 322 OA.]
Sonothrombolysis of porcine blood clots using 1 MHz pulsed ultrasound
Authors: Nourmahnad Atousa , Barbano Luke , Everbach Erich C.
Published: October 2015

Blood clots block proper blood flow in vessels and often lead to fatal health conditions such as cardiac ischemia and stroke, especially in an aging population. Because ultrasonic fields can cause cavitation of fluids, administration of ultrasound and microbubble contrast agents can induce intravascular thrombolysis (dissolution of blood clots). Quantitative and qualitative data were collected on how a porcine blood clot dissolves when exposed to Definity™ microbubbles and 1 MHz pulsed ultrasound. In addition, bubble dynamics in response to the measured ultrasonic wave field were modeled using a modified Gilmore equation. The results allowed us to optimize parameters and better understand the interaction of the clot fibrin structure and the movement of microbubbles through it. Advances in the understanding of sonothrombolysis can help transform its clinical application in patients efficiently, especially in instances where life depends on rapid dissolution of a thrombus.
Operational challenges associated with the use of fit test systems in the U.S. Air Force
Authors: Theis Melissa , McKenna Elizabeth
Published: October 2015

Hearing protection fit test systems provide immediate and direct feedback on the goodness-of-fit for a specific individual based on the personal attenuation rating (PAR) obtained from the measurement. Fit test systems may provide improved retention of hearing protection training, particularly when used in combination with face-to-face training. One challenge for the U.S. Air Force is determining when face-to-face training should occur, and how detailed this training should be to maximize the benefits for end users. A second challenge is determining if various hearing loss patterns render PAR data inaccurate, because many Air Force personnel have hearing loss. The ability of individuals with hearing loss to achieve a desired PAR for a workplace may be influenced by the dynamic range of the system, particularly when measuring the protected condition. This presentation will discuss how the two challenges mentioned above must be investigated before implementing fit test systems as a hearing preservation tool for U.S. Air Force personnel, and discuss some preliminary data obtained in these areas.
Assessing attitudes toward use of hearing protection devices and effects of an intervention based on results of fit testing
Authors: Smith Pegeen
Published: October 2015

As field attenuation estimation systems (FAESs) have become more prevalent, there has been a call from industry to quantify the value of including them into hearing conservation programs. This presentation describes a study that assessed attitudes toward the use of hearing protection devices (HPDs) and the effect of an educational intervention based on results of fit testing by comparing the personal attenuation rating (PAR50) before and after intervention. Employees (n = 327) from a large metal container manufacturer at four geographic locations were tested with a FAES to identify workers (n = 91) needing the intervention. PAR50 values significantly increased from baseline to post-intervention (p < 0.001, 15.1 to 26.9) and at six-month follow-up (p < 0.001, 95% CI = −11.2, −6.3). However, perceived self-efficacy (SE) scores in using HPDs significantly declined from baseline to post-intervention (p = 0.006, 95% CI = 0.3, 1.9) but were not significantly related to PAR50. Therefore, a FAES can assist the health and safety professional to identify workers who are at high risk (low PAR50), teach the proper fit and use of HPDs, and enhance hearing protector selection.
Transmission and reception of ultrasound via a polymer film
Authors: Tohmyoh Hironori , Mukaimine Shota
Published: October 2015

We report on the changes in the waveform of the echo which was transmitted and received via a polymer film inserted between the water and the solid samples. Generally, the frequency characteristics of an ultrasonic transducer are fixed because the piezoelectric element embedded in the transducer is unchangeable. This study is aimed to enhance the flexibility of ultrasonic transducers by freely changing the frequency components of the echo. For this purpose, we paid attention to the frequency dependence of the echo transmittance among three media. A theoretical model for the ultrasonic transmission system comprising the water, the film and the solid sample was developed and the validity of the model was verified by experiments where the ultrasound excited by the ultrasonic transducer was transmitted into the steel samples via a polymer film. The amplitude of the echo was enhanced by the insertion of the film and its frequency components were modulated toward the higher frequency side. It was experimentally confirmed that the waveform of the echo obtained from the sample via a film could be accurately predicted by the theoretical model developed.
Turbulence effects on broadband pulses propagating near the ground
Authors: Wilson D. Keith , Ostashev Vladimir E. , Collier Sandra L. , Cain Jericho E. , Cheinet Sylvain
Published: October 2015

Broadband sound pulses (such as from gunfire and explosions) distort randomly as they propagate through atmospheric turbulence. Recently, a general theory was formulated to describe the statistical moments, including the mean and space-time coherence, of such signals propagating along line-of-sight paths (Ostashev et al., J. Acoust. Soc. Am. 136(5), 2414–2431 (2014)). This presentation focuses on some practical issues related to the physical interpretation of the theoretical predictions for the moments, such as what the theory predicts for pulse signals and turbulence regimes of typical interest, and how the behavior of individual pulse events is reflected in the averages that can be compared directly to the theory. In particular, we examine the conditions when the scattering is dominated by pulse wander (variations in arrival time) and when is it dominated by pulse spread (broadening of the energy in the impulse). Conversion of real-valued signals to analytic signals, and the averaging of these representations, is also discussed.
Wind turbine radiated acoustic signals—Propagation in a temporally and spatial variable marine meteorological boundary layer
Authors: Orr Marshall H. , Gilbert Kenneth E. , Di Xiao , Badiey Mohsen
Published: October 2015

The temporal and spatial properties of an acoustic field radiated from a wind turbine operating in a marine meteorological boundary layer and a spatial temporal variable impedance boundary will be quantified using paraxial equation based numerical simulations. A sound speed field will be constructed using wind field measurements made with a 915 MHZ radar wind speed sensor and local temperature and humidity measurements obtained from a meteorological tower. Temporally variable impedance boundary conditions for a tidal marine marsh will be included in the simulations.
Infrasonic wind noise reduction comparison for wind fences and porous domes
Authors: Abbott JohnPaul , Raspet Richard , Noble John , Alberts W. C. K. , Colliler Sandra
Published: October 2015

This paper reports on an investigation directly comparing the measured wind noise and detected acoustic signals for two types of co-located infrasonic wind noise reduction barriers. The first type is a set of cylindrically shaped wind fence enclosures and the second type is a set of 2.0 m diameter semi-porous fabric domes. The fence configurations included variations to the height, width, and number of filtering layers. Forty and fifty-five percent porosities were used for each of these configurations. Wind Noise reductions for the domes and the 5 m diameter fence are comparable at low wavenumbers, while the reductions for the 5 m fence is better at high wavenumbers. The porous domes and the 6 m high wind fence achieve comparable maximum reduction levels; however, the 6 m high fence mitigates noise for a broader wavenumber range. The 10 m diameter fence achieves the best reduction levels overall, while the porous domes are better at mid-range wavenumbers. Additional filtering layers improve all reductions and show the greatest improvement for the fences and the higher porosity dome.
Empty cavity in a cavitating liquid: Features of flow structure
Authors: Kedrinskiy Valeriy , Bolshakova Ekaterina S.
Published: October 2015

Problem of empty cavity dynamics in a two-phase medium is considered. The initial equilibrium state of “cavity-medium” system is disturbed when pressure inside cavity falls abruptly up to 0. Rarefaction wave arising on an interface initiates a cavitation development. Two-phase mathematical model is applied to investigate the medium state dynamics. The medium parameters correspond to a distilled water state: microbubbles, 1.5 μm, their density 106 cm-3, and gas concentration, about 10-5. The numerical analysis has shown that interface “cavity-medium” becomes a cavitating spherical layer. The concluding process of cavity collapse can be characterized by two stages. First, the interface as a spherical layer in a result of its cumulation is transformed into a spherical bubbly cluster with 1 mm radius. Cluster contains 2.5·105 см-3 microbubbles with 40 μm radii. Gas concentration is distributed from 20%,cluster center, up to 1% on its surface. Second, the cumulation of flow on the spherical bubbly cluster will determine a level of internal energy of compressed bubbly cluster and its further dynamics. The similar phenomenon was found in the experiments on the development, structure, and collapse of a rupture forming in cavitating layer of distilled water at its shock-wave loading. The analysis of experimental data has shown that a rupture in the cavitating layer is the cavity with interface as thin layer of cavitating liquid and its collapse tends to the bubbly cluster formation. [Support RFBR, grant 15-05-03336.]
Acoustic measurements of the noise generated by the Silver Fox Unmanned Aerial System
Authors: Mobley Frank S.
Published: October 2015

Acoustic measurements of the noise generated by the Silver Fox Unmanned Aerial System (UAS) were accomplished on a test fixture at Owens-Corning. These measurements, made in one-percent throttle increments, revealed a region over which the noise power curve was linear. Source noise directivity patterns were constructed for each throttle increment using a spherical harmonic series expansion and compared to directivity patterns constructed using a proposed linear interpolation methodology. Moreover, these predictions from the two source construction methods were compared to validation measurements and demonstrate that the interpolation method is viable for spherical harmonic source representations.
Hearing protection device field attenuation estimation systems
Authors: Stefanson JR W. , Ahroon William A.
Published: October 2015

The United States Army Aeromedical Research Laboratory has conducted comparative, developmental, and evaluation studies for Hearing Protection Device Field Attenuation Estimation Systems (HPD FAES). The Army’s interest in protecting Soldiers’ hearing led to the development of the Communications Earplug (CEP), which couples communication systems with a foam earplug in an attempt to block hazardous noise while still passing to the user the clearest speech signal attainable. A recent developmental study addresses the need to fit-test the CEP when used with foam or custom earplugs in a quick and objective fashion using a field-microphone in real-ear (F-MIRE) procedure. Commercial systems have also been evaluated along with a clinical audiometer used by the Army Hearing Program for application as an HPD FAES. A select few FAESs were studied for their attenuation measurement accuracy as compared to the laboratory standard ANSI/ASA S12.6. Completed and ongoing studies will be presented on the FAESs’ utility, cost, and effectiveness.
Cortical dynamics of spatial and non-spatial auditory selective attention
Authors: Deng Yuqi , Goldberg Hannah , Shinn-Cunningham Barbara , Choi Inyong
Published: October 2015

Auditory selective attention suppresses processing of task-irrelevant stimuli, and it is crucial for effective communication in social settings. Previous studies showed that space- and pitch-based auditory attention engages different neural networks. However, the cortical dynamics underlying spatial and non-spatial auditory attention are unclear. Since accumulating evidence suggests that selective suppression is related to alpha band oscillation (8–14 Hz), we examine the spatial and non-spatial attentional modulation of alpha oscillation power as well as event-related potential (ERP) and behavioral performance. Using Electroencephalography (EEG) in humans, we compare behavior and physiological measures during focused attention (where listeners maintain focus on one “target” stream) and broad attention (where listeners are prepared to switch attention to a “super-target” stream which may or may not appear after the “target” stream) in spatial and non-spatial settings. We find that spatial attention shows overall stronger alpha power and different distribution in the central-parietal cortex. We also find that the monitoring cost of broad attention is higher in spatial attention, which is supported by a stronger ERP modulation. Our findings help elucidate the cortical dynamics involved in spatial and non-spatial auditory attention.
Age-related differences in auditory cortical representations of spatial cues
Authors: Ozmeral Erol J. , Eddins David A. , Eddins Ann C.
Published: October 2015

Converging evidence indicates that binaural processing declines with age and is impaired further by age-related hearing loss. Research in young, normal-hearing adults indicates that spatial coding is governed by an opponent-channel (OC) mechanism. Under the OC model, the sensitivity to changes or shifts in perceived lateralization can be predicted based on the direction and magnitude of the shift, where large, outward shifts are predicted to cause a greater neural response than small and/or inward shifts. It is possible that age-related changes in spatial coding reflect changes in the OC mechanism, perhaps due to reduced neural inhibition or a more general reduction in temporal precision. Cortical event-related responses elicited by both ITD and ILD changes were measured using a 64-channel montage during a passive, continuous change-detection paradigm. Source localized cortical activation patterns were analyzed with regard to degree of lateralized shift, direction of shift (toward or away from perceived midline), and listener group. Results are consistent with an OC mechanism of spatial coding for both younger and older adults. Behavioral data from the same subjects are reported for correlation analyses with neural data. The present study provides a foundation for understanding the cortical dynamics of age-related changes in spatial tuning.
Effects of phase difference on the binaural perceiving intensity
Authors: Kim Sanmun , Kim Young H.
Published: October 2015

It is well known fact that human localize the direction of sound source in transverse plane according to interaural time difference in low frequency and interaural level difference on high frequency. In this research, we tested possibility for interaural time difference to be interpreted as interaural level difference when it is perceived by brain. To test the hypothesis, we used sinusoidal wave and commercial music to study the effect of interaural time difference on the perception of loudness. Each sound sample was regulated to have interaural time difference and given to 9 subjects. Subjects were asked to answer which side was louder. For sinusoidal waves, more than 60% of subjects answered side with earlier sound arrival was louder. The effect of interaural time difference on interaural level difference was larger when it interaural time difference was given to lower frequencies. Music samples were regulated with 100 and 500 interaural time difference and 100% of subjects answered side with earlier sound arrival was louder. Results from the experiments imply the possibility for interaural time difference interpretation by interaural level difference on localization of sound sources.
Stress and strain monitoring in metals and alloys by guided acoustic waves with the aid of anharmonic effects and stress stiffening
Authors: Grill Julian , Grill Wolfgang
Published: October 2015

The basic theoretical features including anharmonic effects allowing structural health monitoring and the detection of stress and strain by guided acoustic waves are exemplified. Experimental results for stress and strain monitoring covering the linear elastic regime and the regime of plastic deformation are demonstrated for brass, copper and a standard aluminum alloy. Practically oriented applications, including also the monitoring of structural defects, load, weakening of structural components by overload and vibrations, and the detection of temperature to compensate for temperature dependent effects influencing structural health monitoring by acoustic waves, are presented for applications involving sections and components of aircrafts.
Characterization of air-coupled ultrasonic receivers for nonlinear Rayleigh wave nondestructive evaluation
Authors: Torello David E. , Kim Jin-Yeon , Qu Jianmin , Jacobs Laurence J.
Published: October 2015

Nonlinear Rayleigh wave measurements can be used to determine damage precursors and measure microstructural material changes while only requiring one-sided access to a specimen. These measurements are extremely sensitive to coupling conditions between the specimen surface and the generating and receiving transducers used in propagation and measurement of the Rayleigh waves. Air-coupled detection offers many advantages to traditional contact techniques because it mitigates these experimental coupling concerns with a reasonable cost as contrasted with other non-contact methods. However, to use these devices to measure absolute nonlinearity in a specimen requires a detailed understanding of the transducers and the experimental setup. This work provides a combined numerical and analytical approach to understanding the received signal and uses this information to determine a framework for calculation of absolute measures of material nonlinearity.
Acoustic cues to the [j]-[i] distinction in American English
Authors: Jaggers Zachary
Published: October 2015

Existing lexical items suggest that American English exhibits a [j]-[i] distinction (e.g., pneumonia [numonjə], Estonia [ɛstoniə]). This study tests if such a distinction can be experimentally elicited in both existing and new items and what acoustic cues most consistently convey it. A sentence reading task elicits the distinction by native speakers of American English using orthographically paired nonce names: 'y' stimuli (e.g., Chobya) expecting [jV] productions, 'i' stimuli (e.g., Shabia) expecting [iV] productions. Stimuli are controlled and diversified along the factors of place and manner of the preceding consonant and word position (initial vs. medial). Multiple acoustic factors of [V] sequences are measured and tested against each other as predictors of stimulus orthography, thus as cues to any elicited distinction, in a generalized linear mixed-effects model. Productions of 'y' stimuli are predicted by significantly earlier transition to the following vowel (represented by timepoint of the F2 maximum), lower F1, and lower intensity. This confirms the presence of the distinction and supports a constriction/height-based classification (Padgett 2008). A significant difference in F2 is not observed; these results are therefore not consistent with a classification of [j] as a coronal sound and [i] as dorsal (Levi 2008).
Acoustic and perceptual correlates of subjectively rated sentence clarity in clear and conversational speech
Authors: Ferguson Sarah H. , Morgan Shae D.
Published: October 2015

Young adults with normal hearing and older adults with hearing loss performed subjective ratings of speech clarity on sentences spoken by all 41 talkers of the Ferguson Clear Speech Database. The sentences were selected from the CID Everyday Sentence lists and were produced under instructions to speak in a conversational manner and in a clear speaking style. A different set of 14 sentences was recorded in each style. Rated clarity will be compared between the two listener groups as well as among subgroups of talkers who differ in demographic and other characteristics. Clarity data will also be analyzed in conjunction with perceptual and acoustic data obtained in other investigations to reveal the relationship between vowel intelligibility and sentence clarity as well as the acoustic features that underlie perceived sentence clarity for different listener groups.
Probability distribution of multiple-target data snapshots applied to large-aperture array processing
Authors: Quijano Jorge E. , Zurk Lisa M.
Published: October 2015

We consider sonar array target detection and azimuth estimation in experimental scenarios consisting of large-aperture horizontal line arrays of hydrophones in the water column. In such scenarios, successful distinction of quiet targets from the background noise strongly depends on having sufficient independent data snapshots available for computation of adaptive beamforming weights. In this work, the discrete Fourier transform matrix is used for projecting the array data into a sparse domain, from which the theoretical probability density function of each (sparse-domain) datum can be obtained. It is shown that the sparse data exhibits a scaled chi-squared distributed magnitude, with a scale factor that depends on signal-to-background noise ratio and array size. Using this theoretical distribution and Monte Carlo simulations, minimum experimental requirements for target detection are quantified and highlight the tradeoff between data sample size, array aperture, and signal-to-noise ratio. In addition, a statistical test to reduce the number of false detections at the output of a beamformer is proposed and applied to simulated and experimental data from the Shallow Water Array Performance experiment.
Nonlinear acoustics and the Acoustical Society of America
Authors: Muir Thomas G. , Browning David G. , Foote Kenneth G.
Published: October 2015

The modern era of nonlinear underwater acoustics had its roots in a remarkable session at the 57th ASA meeting at Providence RI in June, 1960, chaired by Westervelt, of Brown University, who also presented his remarkable new theory of the parametric acoustic array. This conceptual “device” enables highly directive low frequency sound to be created from the nonlinear interaction of two high frequency radiations of high directivity, which was confirmed in a model- tank study paper in this session by Brown Univ. Professor Robert Beyer and student Bellin. JASA has been the major worldwide forum for publications in nonlinear underwater acoustics, ever since, with much of the U.S. work done at the Navy Underwater Sound Laboratory and its successor, the Naval Underwater Systems Center, as well as the Applied Research Laboratories of the University of Texas at Austin. Topics have included parametric arrays, the nonlinear generation of harmonic radiations and transients, acoustic saturation, nonlinear transmitting and receiving sonar and imaging, and many practical applications to underwater sound and acoustical oceanography. Current and/or developing applications include underwater communications, backscattering measurements, penetration of narrow beams into sediments, sub-bottom profiling, and fish school quantification and classification. These and other topics are reviewed and recent implementations are described. [Work supported by ARL:UT Austin.]
Deep-water ocean acoustic propagation: Observations
Authors: Worcester Peter F.
Published: October 2015

There is a rich history of long-range, low-frequency, deep-water ocean acoustic propagation measurements extending back to the discovery of the deep sound channel by Ewing and Worzel in 1944. Experiments up to the 1970s focused on measuring parameters in the sonar equation, including transmission loss and ambient noise, motivated in part by the development of the U.S. Navy Sound Surveillance System (SOSUS). These measurements generally used wideband explosive sources or narrowband transducers. Beginning in the 1970s, low-frequency, broadband transducers and vertical receiving arrays that could operate autonomously and be moored for extended periods were developed in connection with the new field of ocean acoustic tomography. These developments allowed individual multipaths and modes to be resolved and long time series collected, so that the fluctuations in the received signals could be quantified. At about the same time, advances in characterizing ocean internal wave and mesoscale variability provided information on the causes of the acoustic fluctuations that could be used in theoretical calculations. The study of deep-water propagation and the development of ocean acoustic tomography have been intertwined ever since. The applications of deep-water propagation now extend beyond military uses to ocean acoustic remote sensing (active and passive), communication, and navigation.
Acoustic methods for modulating the cavitation initiation pressure threshold
Authors: Tamaddoni Hedieh A. , Duryea Alexander P. , Hall Timothy L.
Published: October 2015

The objective of this study is to develop tissue protection methods by modulating bubble cloud initiation pressure thresholds. Specifically, we investigated pressure thresholds to initiate cavitation bubble clouds by the shock scattering mechanism. Cavitation initiation displays a stochastic nature affected by existing nuclei populations in the medium. We hypothesized that by applying proper low pressure pulse sequences before and/or during histotripsy therapy, initiation pressure threshold and growth of cavitation bubble cloud could be modified. We applied histotripsy and cavitation suppressing pulses in both water and agarose gel for pulse repetition rates of 1, 10, and 100 Hz. Acoustic backscatter signals and optical imaging were used to detect and monitor initiation, maintenance, and growth of resulting cavitation bubble cloud. Results demonstrated that the use of cavitation suppressing pulses can increase the cavitation threshold by 20% in the targeted space. Furthermore, we showed these acoustic sequences could modify the shape and density of the bubble cloud. By applying the cavitation suppressing pulses, we were able to generate a dense cavitation bubble cloud in the focus while decreasing scattered cavitation in the peripheral zone.
Experimental and numerical evaluation of the effect of stone size on fracture by burst wave lithotripsy
Authors: Hubbard Madeline J. , Dunmire Barbrina , Sapozhnikov Oleg A. , Krieder Wayne , Bailey Michael R. , Maxwell Adam D.
Published: October 2015

Burst wave lithotripsy (BWL) is an experimental treatment to noninvasively fragment kidney stones using bursts of focused ultrasound. Preliminary simulations with a linear elastic model showed that resonance creates concentrated stresses, which may help predict locations of fractures in the stones. In this study, we aimed to demonstrate this correlation by comparing simulations to experimental data. Cylindrical stones of variable size (4–14 mm diameter, 10 mm length) made from BegoStone plaster were treated in a water bath for 10 min using a 170 kHz focused transducer at a focal pressure of 6.5 MPa. Locations of first fractures in the stones correlated well with the location of peak stress predicted in the linear elastic model. Simulated peak surface stress in the stones decreased as stone diameter increased, with the exception of a spike near d = 12 mm, which matches the half longitudinal wavelength in the stone. Experimentally, a corresponding overall increase in time to first fracture was observed with diameter, except for a drop at d = 12 mm. The results are encouraging that the model may help direct further optimization of BWL. [Work supported by NIH through DK043881, DK104854, EB007643, and NSBRI through NASA NCC 9-58.]
Focused ultrasound-enhanced intranasal delivery of brain-derived neurotrophic factor
Authors: Chen Hong , Yang Georgiana Z. , Getachew Hoheteberhan , Acosta Camilo , Sánchez Carlos S. , Konofagou Elisa E.
Published: October 2015

The therapeutic use of neurotrophic factors in the treatment of central nervous system diseases has been restrained by their low blood-barrier permeability and rapid degradation in the blood. Intranasal (IN) administration is a promising approach for delivering neurotrophic factors directly to the brain, bypassing the BBB. However, IN delivery has low efficiency and does not offer localized delivery to specific brain sites. The objective of this study was to demonstrate the feasibility of FUS-enhanced IN delivery of brain derived neurotrophic factor (BDNF) at a targeted location. BDNF was administered through IN route in wild-type mice (n = 7) followed by FUS sonication at the left caudaputamen in the presence of systemically circulating microbubbles. The contralateral right caudaputamen was used as control for IN delivery only. Immunohistochemistry staining was used to assess the distribution of BDNF and the bioactivity of BDNF in activating the downstream signaling. It was found that FUS enhanced the delivery efficiency of IN administered BDNF at the targeted region, where BDNF penetrated deep into the brain tissue instead of confining within the perivascular spaces as in the contralateral control side. Furthermore, the delivered BDNF reached sufficient concentration to activate the downstream signaling pathway.
Ultrasound-mediated drug release from nanoscale liposomes using nanoscale cavitation nuclei
Authors: Graham Susan , Kwan James , Myers Rachel , Coviello Christian , Carlisle Robert , Coussios Constantin
Published: October 2015

We have previously presented a liposomal formulation of mean size 140 nm, manufactured using DSPE, cholesterol, DSPC and DSPE-PEG at ratios of 65:25:3:7, which exclusively releases encapsulated doxorubicin in the presence of inertial cavitation nucleated by microbubbles (SonoVue®, Bracco) at peak rarefactional pressures in excess of 1.2 MPa at 0.5 MHz (Graham et al., J. Controlled Release, 2014). However, the benefits of cavitation-sensitive liposomes small enough to pass through the leaky tumor vasculature can only be fully realized if they can be triggered by cavitation nuclei which are also small enough to extravasate into the tumor mass. In the present work, we demonstrate that liposomal release comparable to that mediated by SonoVue® microbubbles can be achieved using gas-stabilizing polymeric nanocups of mean diameter 400 nm, at peak rarefactional pressure amplitudes in excess of 1.5 MPa at 0.5 MHz or 4 MPa at 1.6 MHz. Mechanistically, we hypothesize that release occurs once a threshold peak shear rate is exceeded in the fluid surrounding the collapsing microbubble, thus exceeding the critical shear stress on the liposomal surface. This is confirmed experimentally by demonstrating a correlation between release and the maximum power of broadband acoustic emissions received by a passive cavitation detector.
Hot topics in “cold” acoustical oceanography
Authors: Deane Grant B.
Published: October 2015

Acoustics is a vital tool for probing the ocean interior, the seafloor, and the sea surface. This talk on Acoustical Oceanography will focus on hot topics in cold places, specifically the Arctic. The rapid loss of sea ice in the arctic circle is leading to an increase in human activities, with implications for oil and gas exploration, fisheries, shipping, and tourism, to name a few areas. Current active and exciting research areas in Acoustical Oceanography include: (1) multipurpose acoustic networks in the Arctic that support the passive monitoring of underwater sound, and remote sensing activities such as acoustic tomography and thermometry, (2) using acoustics to track marine mammals and evaluate their responses to industrial noise, (3) the use of high frequency acoustics to detect and quantify oil layers beneath sea ice, and (4) the use of underwater ambient noise to study glacier dynamics and ice melting in arctic, glacial bay.
Schwa reduction and the realization of /p, t/ in casual American English
Authors: Aalders Ellen , Ernestus Mirjam
Published: October 2015

This study focused on the realization of /p, t/ after schwa (e.g., support, certificate) in casual American English. We analyzed the realization of 523 tokens in the Buckeye corpus. Pronunciation variation proved substantial. Some plosives were realized as fricatives or were completely absent; others varied in the duration and voicing of the closure, burst presence, and voice onset time (VOT). Tokens of suppose(d) showed markedly more reduction than other words: schwa was more often absent (80% versus 28%) and VOT was much shorter (mean 19 ms versus 59 ms). We propose that suppose(d) has an additional lexical entry without schwa: spose(d). It is typically assumed that if the schwa is lost, a following voiceless plosive retains the long VOT that is typical in stressed syllable-initial position (e.g., support pronounced as [s’phort]). We compared VOT in our schwa words, excluding suppose(d), with that of 405 plosives occurring after /s/ (e.g., sport, still). Regression analyses showed that VOT was longer in syllable-initial position than after /s/ in consonant clusters (mean 16 ms). Schwa absence did not affect VOT and neither did the duration of schwa when present. This suggests that the reduction processes affecting vowels need not change the realization of consonants.
Influence of clear speech on the word intelligibility of electrolaryngeal speakers
Authors: Cox Steven R. , Doyle Philip C.
Published: October 2015

Electrolaryngeal (EL) speech is often used by individuals who undergo total laryngectomy (Barney, Haworth, & Dunn, 1959; Doyle, 1994). Unfortunately, current EL devices continue to produce an unnatural and mechanical sound quality that can impact speech intelligibility (SI) (Doyle & Eadie, 2005; Hillman, Walsh, Wolf, Fisher, & Hong, 1998; Meltzner & Hillman, 2005). Clear speech (CS) requires speakers to produce speech “as clearly as possible” in an attempt to improve the overall understandability of speech (Picheny, Durlach, & Braida, 1985, 1986) in those with communication disorders (Beukelman, Fager, Ullman, Hanson, & Logemann, 2002; Tjaden, Sussman, & Wilding, 2014). This study addressed alterations in SI through the application of CS by EL speakers. Twelve naïve listeners orthographically transcribed CVC words produced by 10 EL speakers in both habitual and CS modes. Findings indicate that SI improved 1.5% for words spoken using CS (M = 53.25%, range = 47 to 64%) compared to words spoken using habitual speech (M = 51.75%, range = 41 to 62%). No significant differences in SI were found in either word-initial or word-final phonemes across speaking conditions. Clinical implications of these findings will be discussed.
Judgments of self-identified gay and heterosexual male speakers of American English: Certain phonemes are more salient than others in determining sexual orientation
Authors: Tracy Erik C.
Published: October 2015

Prior research (Munson, McDonald, DeBoe, & White, 2006; Tracy, Bainter, & Satariano, 2015) has demonstrated that, upon hearing a relatively short utterance, listeners were able to differentiate between self-identified gay and heterosexual male speakers of American English. Furthermore, Tracy et al. (2015) discovered that listeners primarily relied on certain vowels (e.g., /æ/, /eɪ/, /ε/, /iː/, /oʊ/, /ɑ/, and /uː/) and consonants (e.g., /l/, /n/, and /s/) to determine a speaker’s sexual orientation. The present study, based on data collected by Tracy (2015), investigated whether listeners relied on other phonemes when forming their sexual orientation judgments. Listeners were presented with utterances that either included one, two, or three consonants, or one, two, or three vowels. Upon hearing a single phone, such as /ɪ/, /^/, /ɹ/, /θ/, and /j/, listeners were able to differentiate between the speakers. With respect to the consonants, listeners’ performance improved as the number of certain consonants (e.g., /l/, /n/, /ɹ/, /θ/, and /j/) in the utterance increased. For example, the utterance /ɹ, j, θ/ resulted in better performance than the utterance /f, m, v/. The results indicate that certain phonemes, more than others, can indicate a speaker’s sexual orientation.
Architecture and the environment—How much do we care?
Authors: Roy Kenneth P.
Published: October 2015

We have been hearing about “green buildings” and the drive for energy efficiency and sustainability for quite some time now. And if we think about this, we will probably realize that this focus is really on the buildings and the cost to society that is incurred by these building in terms of environmental factors such as materials, air, and water. This of course does not address the primary reason to design, build, and operate buildings—which is really about “people.” People are exposed to the indoor environmental quality, and up until now, acoustic design and performance have not been exactly exemplary, as shown by POE surveys such as by the CBE at Berkeley. So, what needs to be done to make this work??—Focus on the mission of the building, after all, the building is just a tool to help us do what we need to do. So, how do we address occupant satisfaction and performance with architecture?? And how do we integrate acoustic design into the emerging architectural trends?? That’s what we need to discuss.
Evolution of song complexity in Bengalese finches: Sexual selection and domestication as two factors
Authors: Okanoya Kazuo
Published: October 2015

Bengalese finches (BFs) are domesticated strains of wild white-rumped munias (WRMs) imported from China to Japan 250 years ago. BF songs are composed of multiple chunks and each chunk is a combination of 2–4 song notes. Chunks are then arranged in a finite-state probabilistic automaton. We studied how and why BFs sing such complex songs. We found the following facts. (1) The ancestral strain sing simpler songs. (2) There is high learning specificity in WRMs but not in BFs. (3) BFs have larger song control nuclei and higher level of glutamate receptor gene expressions than WRMs. (4) Both BF and WRM females prefer complex songs as measured by the nest string assay and males with complex songs are physically fitted than the males with simpler songs. These results promoted sexual selection scenario of song complexity in BFs. We further examined factors related with domestication. We examined songs of WRMs in subpopulations of Taiwan. Where there is a sympatric species to WRMs, songs were simpler. This leads to a hypothesis that in the wild songs needed to be simple to secure species identification, but under domestication this constrains was set free. [Work supported by JSPS Kakenhi #23118003.]
Simulation of therapeutic ultrasound treatments using the hybrid angular spectrum technique
Authors: Christensen Douglas , Almquist Scott , Farrer Alexis , Parker Dennis , Payne Allison
Published: October 2015

Numerical simulations play an important role in therapeutic ultrasound treatments. Simulations can help with transducer design, retroactively analyze temperature patterns for insight into treatment effectiveness, and ultimately be used for patient treatment planning. Our group has developed a rapid 3D simulation tool for ultrasound beam propagation named the hybrid angular spectrum (HAS) method. HAS is an extension of the traditional angular spectrum approach that uses fast Fourier transforms to alternate between the spatial frequency domain and the space domain as the beam propagates through inhomogeneous tissue regions. In this presentation, we briefly cover the physical and algorithmic principles underlying the HAS technique, then give examples of its use in two promising high-intensity focused ultrasound (HIFU) applications. First, we employ it to retrospectively predict the heating efficiency of transcranial treatments of 14 patients undergoing treatment for essential tremor using a large phased-array transducer. Phase aberration of the beams caused by skull irregularities is a major effect and must be modeled carefully for accurate results. Second, we model the extent of the phase aberration to be expected in our group’s recently developed MRI/HIFU breast treatment system and show a correlation with the degree of breast tissue inhomogeneity in the path of the beam.