bluuebunny/crossref_metadata_2025 huggingface dataset:
Dyslexia impedes the processing of vocoded speech
Authors: Fox Robert A. , Jacewicz Ewa , Long Gayle , Smith Zane
Published: April 2019

Research has shown that phonological impairment in dyslexia (DYS) is associated with a deficit in recognizing fine-grained details in voices of multiple talkers in both clear and degraded speech [Fox et al., J. Acous. Soc. Am. 141, 3839 (2017)]. These results suggest that DYS listeners may have difficulties in the processing of vocoded speech due to the absence of harmonic information. Given the extensive variability in speech including gender and dialect of the speakers, we can predict that DYS individuals may have limitations using cochlear implants. In the current study, 20 DYS adults and 20 corresponding control listeners heard a set of short sentences/phrases produced by male and female talkers from Central Ohio or Western North Carolina. The utterances were unprocessed or processed through a noise-source vocoder at 4, 8, 12, and 16 channels. In separate experiments, listeners were asked to identify the dialect of the speaker (an ID task) or to repeat the sentence/phrase heard (an intelligibility task). The ID responses (A’ scores) of the DYS listeners were lower than those of the controls at every stimulus level. Similarly, intelligibility responses demonstrated that DYS listeners performed more poorly than did control listeners at every stimulus level.
Contributions to diminished perceptual learning in individuals with language impairment
Authors: Giovannone Nikole , Theodore Rachel M.
Published: April 2019

The lexical context in which sounds occur can help listeners mitigate the challenges of the lack of invariance in the speech signal. Through lexically guided perceptual learning, phonetic category structure can be dynamically modified given repeated exposure to potentially ambiguous sounds embedded within familiar lexical contexts. Individuals with language impairment (LI) show deficits in general auditory processing and speech perception, which may influence the development of stable phonetic category structure. However, it is not yet known whether deficits in phonetic category structure in individuals with LI are related to impairment in the learning mechanisms that guide adaptation or in feedback links from the lexicon to speech sounds. To assess these sources of deficit, participants will complete measures of receptive language ability, a task assessing lexical recruitment (i.e., the Ganong effect), and a lexically guided perceptual learning task. If impairment in phonetic category structure stems from weaker top-down lexical influences, then performance on the lexical recruitment task should be (1) diminished in individuals with LI and (2) predictive of lexically guided perceptual learning. If diminished adaptation instead reflects a disrupted learning mechanism, then individuals with LI and typical participants should perform comparably on the lexical recruitment task despite showing differences in lexically guided perceptual learning.
Effect of number of channels and speech coding strategy on speech recognition in mid-scala electrode recipients
Authors: Berg Katelyn A. , Noble Jack H. , Dawant Benoit , Dwyer Robert , Labadie Robert , Gifford René H.
Published: April 2019

This study investigated the number of channels needed for maximum speech understanding and sound quality in 5 (anticipated n = 10) adult cochlear implant (CI) recipients with mid-scala electrode arrays completely within scala tympani (ST). CI programs with 4–16 active electrodes using a CIS-based strategy were created along with two n-of-m programs (8-of-16 and 12-of-16). Measures of speech understanding and sound quality were assessed. Our hypothesis was that individuals with precurved electrodes localized in ST would have greater channel independence than previous studies demonstrating gains in performance beyond 8 channels. Participants demonstrated performance gains up to 8–10 electrodes for speech recognition and sound quality ratings. Significantly poorer performance was observed using an n-of-m strategy as compared to CIS conditions with 8+ electrodes. These data are in contrast with recent studies for precurved arrays (e.g., Croghan et al., 2017; Berg et al., in review) reporting significant improvement up to 16 to 22 channels. However, the current results are consistent with previous literature (e.g., Fishman et al., 1997; Friesen et al., 2001; Shannon et al., 2011), demonstrating no more than 8–10 independent channels for CI recipients with straight arrays. Implications for device selection and the impact of electrode-to-modiolus distance will be discussed.
Shallow water acoustic propagation prediction
Authors: Clark Cathy Ann
Published: April 2019

A set of propagation loss curves, extracted from measured reverberation in an environment with water depths of 200–250 ft is used to investigate the crossover region between deep and shallow water using two normal mode implementations designed to predict propagation in deep and shallow water, respectively. A third range-recursive calculation which is applicable in situations for which cycle mixing with range results in randomization of phase interference between modes is also used for comparison. The impact of forward boundary scattering on reproducing the measured levels at multiple receiver depths is demonstrated.
Studies on sound absorption performance of porous materials at low temperature
Authors: Wang Xiwei , Yan Xiang , Li Hui , Xue Xiaoyan
Published: April 2019

The acoustical parameters of porous materials are usually tested at normal temperature. In recent years, spaces need acoustical treatments at low temperature spring up with the dynamic tendency of projects such as snow theme parks and high speed trains traveling in the frozen region. The sound absorption coefficient of porous materials at low temperature is very rare for now. So in real projects, the sound absorption coefficient of porous materials at normal temperature is the only reference which is certainly inappropriate. The sound absorption coefficient of several common porous materials is test at −50°C, −25°C, and 25°C. The details of the measurement process and data analysis are specified in this paper.
Pixel-wise deep learning for improving image reconstruction in photoacoustic tomography
Authors: Guan Steven , Khan Amir , Sikdar Siddartha , Chitnis Parag V.
Published: April 2019

Photoacoustic tomography involves absorption of pulsed light and subsequent generation of ultrasound, which when detected using an array of sensors can produce clinically useful images. Practical considerations limit the number of sensors and their “view” of the region of interest (ROI), which can result in significant reconstruction artifacts. Iterative-reconstruction methods can improve image quality but are computationally expensive. Another approach to improve reconstructed images is to use convolution neural networks (CNN) as a post-processing step for removing artifacts. However, missing or heavily obscured features typically cannot be recovered using this approach. We present a new pixel-wise deep learning (PDL) approach that employs pixel-wise interpolation to window ROI-specific raw photoacoustic data and then directly performs the image reconstruction within the CNN framework. The utility of this approach was demonstrated on simulated photoacoustic data from a 64-element semi-circular sensor array. The training and testing datasets comprised of 500 images from a synthetic vasculature phantom and 50 images of an anatomically realistic vasculature obtained from micro-CT images, respectively. The structural similarity index of the PDL-reconstructed images (0.91 ± 0.03) indicated superior image quality compared to those obtained using the iterative reconstruction (0.82 ± 0.09) and CNN-based artifact removal (0.79 ± 0.07).
Emerging imaging methods in biomedical ultrasound
Authors: Mast T. Douglas
Published: April 2019

Possibilities for diagnostic and therapeutic ultrasound imaging methods are continually extended by advances in transducer and beamformer technology, algorithms for signal processing and image reconstruction, research-oriented imaging platforms, and computing power. This talk describes and illustrates recent advances in biomedical ultrasound imaging methods from multiple groups. In different respects, each provides information beyond the tissue reflectivity, blood flow, and strain mapped by current clinical ultrasound scanners. Methods discussed include quantitative imaging of tissue parameters by solving inverse scattering and inverse elasticity problems, super-resolution imaging beyond the diffraction limit, and passive imaging of acoustic cavitation. Physical acoustics principles underlying the methods, as well as applications in diagnosis and therapy guidance, are discussed.
Simultaneous trapping and pulling by acoustical Bessel beams as stable tractor beams
Authors: Fan Xudong , Zhang Likun
Published: April 2019

A stable tractor beam for long range pulling of particles by acoustic Bessel beams requires a simultaneous trapping in the lateral direction. Trapping force acting on a sphere centered on the axis of Bessel beams is examined to guide the selection of material and beam parameters. It is found that a heavy and rigid sphere in the Rayleigh regime can be trapped at central pressure maximum of zero-order Bessel beam, which is contrary to the repelling behavior at the pressure anti-nodes of one- or two-dimensional standing waves. The trapping results from the three-dimensional features of the velocity fields and the momentum projection. The projection leads the trapping of an elastic sphere or a droplet at the axis of ordinary and vortex Bessel beams in the Rayleigh regime to be reversed when reducing the conical angle of the beam at the situation when there is a strong contrast of mass density between the particle and the surrounding fluid. Ranges of conical angle and material parameters for simultaneous trapping and pulling a spherical object are identified.
An acoustics separation technique based on the development of an interface in the acoustic field
Authors: Kumar Krishna N. , Barber Adrian , Saloio Jack , Campbell Tyler , Chitale Kedar C. , Ross-Johnsrud Benjamin P. , Lipkens Bart
Published: April 2019

Chimeric antigen receptor (CAR) T-cell therapy is a promising and evolving immunotherapy approach for cancer treatment. In allogeneic CAR-T therapies, TCR + cells must be removed from the final cell product because of immunogenicity problems. It is accomplished through a negative affinity cell selection process where TCR + cells are affinity bound to a bead. The harvested TCR-cells are the product cells. A multidimensional acoustic standing wave field separates cell-bead complexes from free cells in an acoustic fluidized bed. The feed solution motion is normal to the primary acoustic field. Irrespective of the particle acoustic contrast, an interface between a dense suspension on the bottom and clear fluid on top develops in the field. We examine the physics behind the development of the interface and its subsequent motion. This motion influences the purity, scalability, and recovery of the TCR- cells. We present the effects of different acoustofluidic parameters, e.g., bead concentration, bead acoustic contrast factor, frequency, and flow rate on interface formation and its movement. Theoretical calculations and experimental results are discussed. The acoustic fluidized bed has been shown to give final purities of 99 + % of TCR- cells from a starting purity of 60%–70%, with 70 + % recoveries of TCR- cells.
Droplet extraction and manipulation at a fluid interface using fraxicon modified ultrasound
Authors: Lirette Robert L. , Mobley Joel , Zhang Likun
Published: April 2019

Ultrasound focused at a fluid-fluid boundary creates an acoustic radiation pressure on the boundary that is dependent on the incident energy density and the relative density and sound speed of each fluid. For different fluid combinations, this radiation pressure can either be positive or negative. For this study, ultrasound propagating from water to carbon tetrachloride was used to create a negative radiation pressure at the interface. This fluid combination is impedance matched eliminating reflections and heating effects at the boundary. A fraxicon phase plate lens is a low profile analog of an axicon and generates an approximate Bessel beam in the far field. The near field exhibits a complex diffraction pattern including shadow zones capable of acoustic trapping. Starting with a planar interface, we demonstrate the extraction, capture, and manipulation of a carbon tetrachloride droplet. The negative radiation pressure draws the carbon tetrachloride surface up into the water, eventually breaking a droplet free. The trapped droplet is then transported through the water by moving the transducer.
The role of linguistic variability in the perception of voice cues
Authors: Arts Floor , Gaudrain Etienne , Tamati Terrin N. , Baskent Deniz
Published: April 2019

Talkers’ voices play an important role in speech perception. Through voices, we identify individual talkers and can facilitate speech communication in challenging conditions (e.g., cocktail party situations). While previous research has suggested that several linguistic factors broadly influence talker perception, how these factors influence perception of the individual voice cues remains unclear. The current study investigated the role of linguistic variability in voice cue perception, specifically fundamental frequency (F0) and vocal-tract length (VTL). Just-Noticeable-Differences (JNDs) were obtained using a 3AFC adaptive paradigm. Effects of word status (words, nonwords), word characteristics (lexical frequency, neighborhood density), and nonword characteristics (phonotactic probability, neighborhood density) were examined. Results demonstrated that voice cue perception was influenced by linguistic variability. While overall similar for words and nonwords, F0 and VTL JNDs were affected by phonological information in nonwords, i.e., phonotactic probability, but not on lexical information, i.e., lexical frequency and neighborhood density. However, VTL JNDs varied less across linguistic conditions than F0 JNDs, suggesting different processing mechanisms for these voice cues. These findings provide better insight into the interaction of voice and linguistic information, which may also improve our understanding of speech perception processes in populations with limitations in voice perception, such as cochlear-implant listeners.
More information is more information: Working memory and visual context
Authors: Lowenstein Joanna H. , Nittrouer Susan
Published: April 2019

Listeners with cochlear implants demonstrate diminished auditory-verbal working memory capacities, possibly due to a lack of durable codes in the memory buffer. Earlier studies suggest that the context provided by lip-read information should enhance those codes, with both the phonological form and dynamic nature of lip-read signals contributing to this facilitative effect. The purpose of this study was to test the hypothesis that lip-read signals would make uniquely beneficial contributions to the recognition of degraded speech. To test this hypothesis, three kinds of signals were used: unprocessed words, vocoded words, and nonspeech environmental sounds. Two kinds of visual enhancements were applied: (1) dynamic signals specifying the event that generated the signal or (2) pictures representing the object named or creating the signal. Eighty young adults with normal hearing were asked to recall order of eight-item lists in a closed-set format. All listeners heard lists in all three signal conditions (unprocessed, vocoded, environmental sounds) but half recalled order in each visual-enhancement condition. Adding lip-read information improved accuracy and eased cognitive demands for recall of vocoded words, but other visual information provided benefits as well, calling into question previous claims of the specialness of dynamic facial movements.
Shaping shock transmission with lightweight elastomeric materials
Authors: Harne Ryan L. , Vuyk Peter
Published: April 2019

Effective suppression of impulsive elastic waves requires the reduction of the transmitted shock pulse and the elongation of shock duration. Recent experimental studies with engineered, lightweight elastomeric materials suggest that these requirements are met to large extent. The materials capitalize upon the mesoscale geometry that is known to collapse in unique ways according to the internal geometric design and magnitude of the impact force. Yet, the relations among material design, collapse trend, and resulting shock mitigation remain unknown. This research seeks to shed light on the connections using digital image correlation techniques that uncover exact origins of energy distribution through mapping of local strain fields. With a sequence of controlled shock experiments, we first identify how the impact force magnitude governs the classification of shock mitigation capability of the materials. Then, the relative variations of such trends as tailored by the internal material geometry are examined. All together, the results illuminate the range of working conditions and material designs for which shock attenuation capability of the materials remains exceptional.
Experimental design for the accurate measurement of ultra-low damping of simple structures
Authors: Hall Hubert S. , Dlubac James J. , Kim Michael
Published: April 2019

As a means of validating numerical models, recent research has shown a need for methodology to measure the structural damping of very lightly damped structures (loss factor < 0.005) to a high level of accuracy. Traditional experimental methods of measuring structural damping must be altered to accurately capture the lightly damped response. Otherwise, inaccurate damping values will be calculated that are larger than those intrinsically found in the material/structure. This presentation focuses on experimental technique modifications required for frequency domain methods of measurement of ultra-low damped structures. First, the implications of less accurate capture of resonant peaks in frequency response functions will be explored. Typical short frame, uniform frequency spacing can result in large measurement errors with lightly damped test articles. Instead, long time histories, focused sine-based testing, zero-padding, and peak approximation methods should be utilized for improved accuracy. Additionally, the effects of isolation-related boundary conditions and instrumentation mass to measurement accuracy are explored and quantified.
Task-evoked pupillary response to completely intelligible accented speech
Authors: McLaughlin Drew J. , Van Engen Kristin
Published: April 2019

Listening to second language- (L2-) accented speech is often described as an effortful process, even when L2 speakers are highly proficient. This increase in listening effort is likely caused by systematic segmental and suprasegmental deviations from native-speaker norms, which require additional cognitive resources to process (Van Engen and Peelle, 2014). In this view of speech perception, even when an L2 speaker is completely intelligible (i.e., their words can all be correctly identified), perception nonetheless requires increased cognitive load compared to native speech. We used pupillometry (the measure of pupil diameter over time) as a psychophysiological index of cognitive load to address this hypothesis. Task-evoked pupillary response (TEPR) was measured while participants listened to sentences produced by a Mandarin Chinese-accented English speaker and a standard American-accented English speaker. Results from a first experiment showed that TEPR was larger for L2-accented speech than the native speech, indicating greater cognitive load during speech processing. In a second experiment, we controlled for differences in the speech rate between the two speakers. Preliminary evidence from this replication also shows larger TEPR for the L2-accented speech condition. Together, this evidence suggests that processing accented speech—even when completely intelligible—requires additional cognitive resources.
Production and perception of two English vowels by advanced Colombian Spanish learners of English
Authors: Conklin Jenna , Dmitrieva Olga , Pineda Mora Gina M.
Published: April 2019

This study investigates the acquisition of the English vowels [æ] and [ʌ] by Colombian learners of American English. Thirty speakers of Colombian Spanish residing in the United States participated in this study. A multiple-choice identification task demonstrated that participants were proficient at identifying [æ] and [ʌ], though the accuracy rate was somewhat lower than for a number of other English vowels used for comparison. When misidentified, [æ] and [ʌ] were most frequently confused with each other or with the low back vowel [ɑ]. In a production task completed by both bilingual Spanish speakers and monolingual English speakers, learners’ [æ] and [ʌ] were distinct from native monolingual English productions. The nature of the acoustic differences between native speakers’ vowels and learners’ vowels suggested that Colombian speakers’ English renditions of [æ] and [ʌ] were affected by their Spanish [a]. Further analysis revealed that learners’ [æ] was not statistically different from their own production of Spanish [a]. These results are compatible with the assumption emerging from previous research that speakers of Spanish acquiring English assimilate, to a varying degree, English low and low-mid vowels to Spanish [a]—a single vowel found in this area of the vowel space in Spanish.
The development of perception of English tense-lax vowel contrast by monolingual English-speaking and bilingual Mandarin-English children
Authors: Yu Lan
Published: April 2019

This study explored the perceptual weighting utilized by children and adults for the perception of the English tense-lax vowel contrast in both the first language (L1) and second language (L2). Both the desensitization hypothesis (Bohn, 2000), which posits a universal bias toward duration cues on non-native vowel contrasts, and developmental perceptual weighting shift hypothesis in L1 (Nittrouer et al., 1993), which suggests a shift from dynamic to static cues developmentally, were tested in this study. Listeners were 4 English monolingual children (EC) with a mean age of 6:9, 4 Mandarin-English bilingual children (MEC) with a mean age of 8:4, 4 English-speaking adults (EA), and 4 Mandarin-English bilingual adults (MEA). In an identification experiment, listeners identified stimuli from beat/bit and sheep/ship continua differing in six acoustically equal duration and spectral steps. EC, MEC, and EA rely on spectral differences exclusively, yet MEA utilize an additional cue, duration, to identify this contrast. Findings suggest that desensitization needs to be interpreted with caution since other factors might greatly shift the perceptual weighting such as the age of L2 acquisition and the amount of L2 exposure. As for a developmental perceptual weighting shift, it only applies to the perception of consonants not vowels.
Silver Medal in Engineering Acoustics 2019: Thomas B. Gabrielson
Authors: Gabrielson Thomas B.
Published: April 2019

The Silver Medal is presented to individuals, without age limitation, for contributions to the advancement of science, engineering, or human welfare through the application of acoustic principles, or through research accomplishment in acoustics.
Gold Medal 2019: William J. Cavanaugh
Authors: Cavanaugh William J.
Published: April 2019

The Gold Medal is presented in the spring to a member of the Society, without age limitation, for contributions to acoustics. The first Gold Medal was presented in 1954 on the occasion of the Society's Twenty-Fifth Anniversary Celebration and biennially until 1981. It is now an annual award.
Should we still rely on statistical calculations for the prediction of reverberation time?
Authors: Jaramillo Ana M. , Olson Bruce
Published: April 2019

Based on the conditions for the use of the most commonly used reverberation time equations, we have created room examples in EASE to compare how they correlate with ray tracing predictions and established a guideline on when we can rely on simple statistical predictions. The results show that statistical predictions are not always accurate, and the differences do not always go in the same direction, making it impossible to simply account for the under/over-estimation of the method.
An Artificial Neural Network (ANN) approach to extract micro-architectural properties of cortical bone using ultrasound attenuation: A numerical study
Authors: Mohanty Kaustav , Yousefian Omid , Karbalaeisadegh Yasamin , Ulrich Micah , Muller Marie M.
Published: April 2019

The goal of this study is to estimate the porosity parameters including pore diameter, pore density, and porosity of cortical bone from ultrasound attenuation measurements using an artificial neural network (ANN). Two-dimensional (2D) finite-difference time-domain simulations are conducted to calculate the frequency-dependent attenuation in the range of 1–8 MHz in mono-disperse structures (constant pore size) with a pore diameter and density ranging from 20 to 120 µm and 3–16 pore/mm2, respectively. Furthermore, poly-disperse structures (non-uniform pore distribution) are obtained from high resolution CT scans of human cortical bone and 2D numerical simulations are carried out in the same frequency range as for the mono-disperse cases. Then, a regression problem is formulated with the ultrasonic attenuation at different frequencies acting as the feature vectors and the output being set as the porosity parameters. Our dataset consists of 330 structures for the mono-disperse model and 668 structures for the poly-disperse model. ANN-based (3 hidden layers with 806 trainable weights) parameter prediction method achieves accuracies as high as 96% for pore size, 97% for porosity, and 78% for pore density for the poly-disperse model. This work demonstrates the potential of combining ultrasound methods to deep neural networks to quantify cortical bone parameters with high accuracies.
Investigation into tendon histotripsy
Authors: Smallcomb Molly , Simon Julianna C.
Published: April 2019

Histotripsy uses cavitation bubble clouds or shock wave heating and millisecond boiling to fractionate soft tissues. While this modality has proven successful in debulking most soft tissues, highly collagenous tissues such as tendons have proven resistant to mechanical fractionation using histotripsy. In this study, ex vivo rat and bovine Achilles tendons were placed at the focus of a 1.5-MHz transducer and exposed to 1–20 ms pulses repeated at 1 Hz for 1 min over ranges of acoustic pressures up to p +  = 88 MPa (peak positive), p = 20 MPa (peak negative). Simultaneous ultrasound imaging with the Verasonics® research ultrasound system and ATL L7-4 transducer monitored bubble activity, or hyperechogenicity, during the histotripsy exposure. Collected samples were stained with Hematoxylin and Eosin for histological analysis of tissue disruption. Preliminary results show hyperechogenicity within the tendon during the histotripsy exposure; however, thus far only thermal injury has been found histological. The threshold to detect hyperechogenicity in the tendon for 10-ms pulses were p +  = 63 MPa, p = 19 MPa. Future work involves additional parameter testing to promote mechanical fractionation rather than thermal injury of tendons. [Work supported by Penn State College of Engineering Multidisciplinary Research Seed Grant]
Ex vivo thermal ablation monitoring using three-dimensional ultrasound echo decorrelation imaging
Authors: Ghahrahmani Z. Elmira , Grimm Peter D. , Cox Michael T. , Eary Kathryn J. , Dayavansha E. G. Sunethra , Mast T. Douglas
Published: April 2019

Echo decorrelation imaging is a method for quantitatively mapping transient heat-induced changes in pulse-echo ultrasound images. For clinical thermal ablation of liver cancer using radiofrequency or microwave ablation (RFA or MWA), real-time three-dimensional (3D) echo decorrelation imaging is necessary because the entire tumor, with typical diameter 2–5 cm, is ablated at once. We present a method for constructing 3D echo decorrelation maps during radiofrequency ablation (RFA) in ex vivo bovine liver using beamformed in-phase and quadrature (IQ) echo acquired from a Siemens Acuson SC2000 scanner and 4Z1c matrix array. To directly compare echo decorrelation images to the desired outcome of tissue ablation, 3D echo decorrelation images are compared to volumetric reconstructions of the thermal ablation zone, obtained from optical scans of regularly spaced tissue sections. Capability of echo decorrelation as a predictor of local ablation is assessed using receiver operator characteristic curve analysis. Similar to previous studies of two-dimensional echo decorrelation imaging, good correspondence is seen between 3D echo decorrelation images and ablated tissue histology.
Focal power efficiencies achieved with aluminum Fresnel and fraxicon low-profile lenses
Authors: Lirette Robert L. , Mobley Joel
Published: April 2019

Fresnel and fraxicon phase plate lenses modify incident acoustic radiation by a series of phasing steps. A Fresnel lens is designed to approximate a spherical lens, and a fraxicon is designed to approximate an axicon generating a non-diffracting Bessel beam out to a depth of focus. For this study, two lenses were manufactured out of aluminum, a Fresnel with a focal point of 5 cm and a fraxicon with a DOF of 10 cm. Each lens was bonded to a 1.2-MHz piezoelectric driver with epoxy and the assemblies mounted in PVC housings for use under water. The field from each was measured by a hydrophone scanned in the transverse planes. Using an acoustic force balance, the electromechanical conversion efficiency was measured to be roughly 50% for each. The focal power fraction, defined as the ratio of the power within the -6 dB boundary of the focus to the total emitted power, was determined for both transducers. The results are compared to numerical simulations and previously published results.
Multi-channel broadband receive array for downward looking sonar applications
Authors: Todd Bryan D. , Kennedy Jermaine L. , Malphurs David E.
Published: April 2019

The recent proliferation in interest for increased detection and classification probabilities of submerged objects in maritime environments has established a need for broadband underwater acoustic receivers. A multi-channel sonar receive array composed of 16 piezoelectric ceramic elements was designed, fabricated, and developed using rapid prototyping techniques including a combination of three-dimensional printed materials, molding, and casting techniques to support various modalities of underwater sonar sensing applications. Four sets of the receive elements, consisting of four individual elements per set, were mounted using disparate methods. In-water acoustical property characterizations over a broad operating frequency range were examined and analyzed. The aforementioned results fostered identification of key array design characteristics for super-critical grazing angle downward looking sonar (DLS) systems.
Analysis of a passive radio frequency excited acoustic transducer
Authors: Thompson Charles , Jallah Johnetta , Remillard Grace , Chandra Kavitha
Published: April 2019

In this paper, the acoustic sensitivity of passive transducers excited at radio frequency is examined. This wireless battery-free sensing platform derives its power from an externally applied electromagnetic field generated by a radio transmitter. The audio signal is encoded in the backscattered electromagnetic field. Electro-Mechano-Acoustical analogies are developed and presented. Power generation, sound transduction, and radio frequency backscatter transmission of the audio signal are examined.
Preliminary analyses of seismo-acoustic wave propagation in outdoor field-scale analog volcanic explosions
Authors: Neilsen Tracianne B. , Matoza Robin S. , Maher Sean , McKay Margaret G. , Sanderson Richard , Valentine Greg A. , Sonder Ingo , Harp Andrew G.
Published: April 2019

Shallow and subaerial volcanic processes radiate infrasound directly into the atmosphere; sampling these infrasound complement seismic data and aids with physical quantification of explosive eruption mechanisms. More advanced quantitative models of the infrasonic source and associated seismo-acoustic wave conversion and coupling have the potential to improve volcano monitoring capability. Field-scale outdoor experiments under relatively controlled conditions provide the opportunity to test, refine seismo-acoustic wave propagation and source inversion strategies, and provide a critical bridge between laboratory-scale experiments, numerical simulations, and full-scale volcano field data. We present preliminary investigations of data collected during an NSF-sponsored workshop at the University at Buffalo in July 2018. Sets of buried explosives were detonated sequentially. The explosions were recorded at 30–330 m on colocated broadband seismometers buried at 1 m, infrasound sensors, and microphones. Analyses of waveform signatures, including cross-correlation and coherence analyses, provide insights into coupling between seismic and acoustic signals over different frequency bands as a function of distance. Comparisons of the seismo-acoustic coupling for a variety of blast strengths and detonation sequences provide insights into how seismo-acoustic coupling scales with amplitude and source depth. The use of both microphones and infrasound sensors highlights the potential benefit of wideband volcano-acoustic recordings.
Acoustic resonances of atmospheric oscillations
Authors: Godin Oleg A. , Zabotin Nikolay A. , Zabotina Liudmila
Published: April 2019

Atmosphere responds in a resonant way to broad-band excitation by earthquakes, volcano eruptions, and convective storms. Energetic oscillations, known as acoustic resonances, occur at frequencies of 3.5–4.5 MHz and involve infrasound propagation between lower thermosphere and either the ocean or the solid earth. Several approaches have been proposed in the literature to determine the conditions of the acoustic resonances occurrence, predict their frequencies, and relate the frequencies to thermal structure of the atmosphere. This paper presents an asymptotic theory of atmospheric resonances. Contributions to the resonance condition of the Berry phase of infrasonic waves as well as phase shifts at turning points and at reflection from the ground surface are discussed. Unlike low and middle latitudes, acoustic resonances are predicted to be a seasonal phenomenon in polar regions. Excitation of atmospheric resonances by plane-wave vertical displacements of the ground surface and by finite sources is considered. Asymptotic predictions are compared to results of numerical simulations. Infrasound tunneling between turning points via evanescent waves is shown to play a critical role in ionospheric manifestations of the acoustic resonances. [Work supported in part by NSF.]
Musical emotion perception in bimodal patients: Relationship between bimodal benefit and neural representation of temporal fine structure using Rhodes piano stimuli
Authors: D'Onofrio Kristen , Smith Spencer , Kessler David , Williams Grace , Gifford René
Published: April 2019

Combining electric and acoustic hearing across ears allows significant “bimodal hearing” benefit for speech recognition, sound quality, and music perception. The degree of bimodal benefit for speech recognition and musical emotion perception is significantly correlated with neural representation of F0 envelope using the frequency following response (FFR) for a 170-ms /da/ stimulus (D’Onofrio et al., in prep). The purpose of the current study is to examine the relationship between bimodal benefit for musical emotion perception and neural representation of F0 using Rhodes piano stimuli at the following fundamental frequencies: 98 Hz (G2), 262 Hz (C4), and 440 Hz (A4). Our hypotheses are (1) the correlation between bimodal benefit and neural representation of F0 and temporal fine structure will be strengthened via use of a “music” stimulus, compared to the /da/ “speech” stimulus, and (2) bimodal benefit for speech recognition will be better explained via FFR for speech stimuli. Stimuli were presented at 90 dB SPL to the non-implanted ear of bimodal listeners using magnetically shielded insert earphones. Implications regarding the clinical utility of FFR will be discussed, with particular attention given to its use as an objective measure of expected bimodal benefit for speech recognition and musical emotion perception.
On the investigation of the natural mode characteristics of an internal supporting substructure interacting with a submerged main structures in terms of acoustic radiations
Authors: Chen Pei-Tai
Published: April 2019

This paper investigates acoustic radiation characteristics of an internal structure supported in a submerged main structure. An exciting force is applied on the internal structure where vibration is transmitted across the interfacial boundary between these two structures and radiating acoustic power into water through the surface contacting with water. In the previous study (Chen, in 176th ASA meeting, Vol. 144, p. 1680), compliant matrices describing the internal structure and the main submerged structure are proposed, which are both symmetric matrices where the imaginary part of the compliance matrix of the submerged main structure is responsible for acoustic radiation, whereas the matrix for the internal supporting structure is real. These two compliance matrices which are defined on the interfacial boundary fully describing the submerged structural dynamics of this coupled system. It was shown that the parameters, such as thickness and stiffened plate, of the internal structures are very sensitive variations of acoustic radiations, although the stiffness of the internal structures are much lower as compared with the main submerged structure. The present study addresses the natural mode characteristics of the internal structure, such as natural frequencies and mode shapes, affecting power flow across the connecting boundary and thus radiating into water. Two sets of modal expansions for forces and displacements defined on the connecting interfacial boundary are established to investigate acoustic radiations.
A review of techniques for ultrasonic indoor localization systems
Authors: Aparicio Joaquín , Álvarez Fernando J. , Hernández Álvaro , Holm Sverre
Published: April 2019

Accurate localization in indoor environments is crucial for the correct operation of location-aware and augmented reality applications, indoor navigation, and inventory management, among others. Magnetic, radiofrequency and inertial navigation systems typically provide room or meter-level accuracy. Despite being the most widely used, they are affected by error drifts or changes in the environment where they operate, and their accuracy is a drawback for certain applications, such as navigation. Optical-based systems provide better accuracy, but they can be expensive, and they are not privacy-oriented. Ultrasonic positioning systems can also give room-level accuracy, as acoustic propagation is contained within the room walls, helping resolve room or floor-level ambiguities of radio systems. They can even achieve centimeter-level accuracy and ensure privacy, while being low cost. These properties highlight acoustics as a versatile technology for different indoor localization applications, as stated by the research published almost over the last three decades. In this work, the operating principles of the different techniques employed by acoustic positioning systems are reviewed, covering narrowband and wideband systems (including the differences between coded and uncoded transmissions), fingerprinting, and the most recent systems based on machine learning.
Strategies for linking ocean state uncertainty to acoustic uncertainty
Authors: Duda Timothy F. , Zhang Weifeng G. , Lin Ying-Tsong , Newhall Arthur
Published: April 2019

Estimating uncertainty of underwater sound fields caused by partially known environmental conditions is a broad topic with many branches because acoustic fields have many characteristics and many descriptors. Specific field characteristics, each uncertain, influence sound use in specific ways. Multiple descriptors (parameters) of signals of interest, and noise, need to be adequately known to examine use scenarios. This is also true for field simulation, processor simulation, field uncertainty simulation, and processor uncertainty simulation. Parameters should be prioritized for efficient quantification of uncertainty. For example, spatial coherence uncertainty applies to array processing but possibly not to single-sensor processing. Linking environmental uncertainty to field uncertainty, then to task performance uncertainty suffers from the many degrees of freedom present in the environment, and the interconnected effects of the many variable environmental parameters. Here, linkage frameworks for sound within internal waves propagating in variable conditions are examined. Methods appropriate for deterministically defined wave groups are explored, as well as statistically described wave fields. First, wave parameters and parameter uncertainty are specified, then effects on the sound parameters are estimated, as well as derived quantities like probability of detection and direction of arrival. Canyon environments that we have studied with models provide one test bed.
Simulation of a coupled room scenario based on geometrical acoustics simulation models
Authors: Aspöck Lukas , Vorlaender Michael
Published: April 2019

As part of the most recent room acoustical simulation Round Robin, a coupled room scenario, consisting of a laboratory room and a reverberation chamber, is investigated. The evaluation of the participants' results, all using geometrical acoustics based simulation models, however, showed that the measured double slope of this scenario could not be matched by any of the six algorithms. In addition to the presentation of the measured and simulated results for this scenario, this work discusses the role the input data, especially the applied absorption coefficients, and the configuration of the simulation model. Eventually, additional results for one simulation model are presented to demonstrate the options and the limitations regarding the simulation of coupled volumes using geometrical acoustics models.
Auralization of virtual concerts: A subjective evaluation comparing binaural and ambisonic rendering
Authors: Thery David
Published: April 2019

Auralization renderings have reached a sufficient level of maturity that simulated auralizations can be comparable to measured ones. These auralizations can be rendered over a variety of sound systems, potentially combined with a visual model through VR interfaces. This study presents a perceptual evaluation of auralizations of a small ensemble virtual concert rendering, comparing a tracked binaural rendering to 2nd order Ambisonic rendering over a 32 loudspeaker array. The geometrical acoustic model of several actual performance spaces were created and then calibrated using in situ omni-directional room impulse response measurements. The performance stimuli consisted of 3 extracts of jazz anechoic recordings comprising trios and quartet ensembles, augmented by three-dimensional visual point-clouds of the musicians playing on stage. Participants of the listening test included a range of listening expertise level (acousticians, architects, students). Several room acoustical parameters were evaluated between rendering systems, seating positions, and rooms.
Development and characterization of acoustically responsive exosomes for simultaneous imaging and drug delivery applications
Authors: Osborn Jenna , Pullan Jessica , Froberg James , Choi Yongki , Mallik Sanku , Sarkar Kausik
Published: April 2019

Exosomes are naturally secreted bilayer vesicles ranging in size from 40 to 200 nm that play a critical role in cell-to-cell communications and protein and RNA delivery. Researchers have explored exosomes as potential drug delivery vehicles due to their natural morphology and small size. Here, for the first time, bovine milk derived exosomes have been modified to be acoustically responsive as potential ultrasound contrast agents or a drug carrier. The echogenic exosomes were formed through a freeze-drying process in the presence of mannitol. The size and morphology of the particles were assessed with a qNano™ and atomic force microscopy (AFM). The ultrasound response of these particles was characterized through linear and non-linear scattering behaviors. The presence of the echogenic exosomes enhances the scattered signal by 11.4 ± 6.3 dB. The stability of these particles under constant ultrasound exposure were assessed to be similar to that of echogenic polymersomes. The variation of mannitol concentration was assessed. To assess the imaging improvement of ultrasound imaging, the exosomes were injected through a tail vein in mice. The modification of the echogenic exosomes shows to have great promise as potential ultrasound contrast agents or ultrasound responsive drug delivery system.
Therapeutic ultrasound for improving the tropical corneal delivery of macromolecules
Authors: Almogbil Hanaa H. , Daszynski Camille , Rodriguez Erik A. , Singh Tania , Stepp Mary Ann , Zderic Vesna
Published: April 2019

The goal of this project is to facilitate the delivery of topical drugs into the cornea and anterior segment of the eye using therapeutic ultrasound which could present a promising treatment for keratoconus and other corneal diseases. Each cornea is dissected and placed in a diffusion cell. smURFP-blue, a blue fluorescent chromophore, was used as the drug. The experimental groups of corneas were treated with 1 and 0.8 W/cm2 continuous ultrasound for 5 min at frequencies of 400 kHz and 600 kHz, respectively, then left in the diffusion cell for another 55 min. Fluorescence images of the fixed corneas were obtained to determine the relative amount of smURFP-blue that remained in the tissue. Safety of ultrasound application was tested by comparing the damage in the corneal layers. Spectroscopy measurements indicated no statistical difference in the presence of the chromophore in the receiver compartment in ultrasound- and sham-treatment groups. Preliminary results showed greater fluorescent intensity in the cornea when smURFP-blue is delivered with ultrasound compared to smURFP-blue added without ultrasound. The histology studies did not show any significant damage in ultrasound-treated corneas. This work may allow for the development of an inexpensive, clinically applicable, and minimally invasive ultrasound method for corneal drug delivery.
Design and characterization of tabletop anechoic and sonication chambers
Authors: Ott Olivia , Lani Shane , Sari Jim
Published: April 2019

Access to anechoic chambers for acoustic testing can be an expensive and limited resource for acousticians. The purpose of this work was to develop small scale, portable anechoic and sonication chambers that could be used for rapid and simultaneous testing. Using consumer off the shelf (COTS) products, low cost anechoic and sonication chambers were designed and built. Upon completion the prototypes were characterized for their acoustic performance. Both the anechoic and sonication chambers were characterized by their ability reduce ambient noise. The characterization was completed by measuring transmission loss (TL) through the chamber walls. Second, the sonication chamber was tested for spatial sound pressure level (SPL) variation. The procedure for spatial testing inside the chamber included measuring SPL along a horizontal stage using mini microphones. The performance and characterization of these chambers will be presented and discussed.