bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel use of a lung ultrasound sensor for detection of lung interstitial syndrome
Authors: Khokhlova Tatiana D. , Maxwell Adam , Thomas Gilles P. , Thiel Jeff , Peek Alex T. , Cunitz Bryan W. , Bailey Michael R. , Steinbock Kyle , Anderson Layla , Kessler Ross , Adedipe Adeyinka
Published: November 2021

The number and distribution of lung ultrasound (LUS) imaging artifacts—B-lines—is correlated with the presence of lung interstitial syndrome such as viral infection, acute respiratory distress syndrome, and pulmonary edema. The detection and quantification of B-lines requires specific training and is machine and operator dependent. In select clinical scenarios continuous hands-free monitoring of lung function is preferred, e.g., COVID-19 infection. The goals of this work were to: (1) identify RF signal features associated with B-lines and (2) develop a single-element, wearable, automated non-imaging lung ultrasound sensor (LUSS) for continuous monitoring. Verasonics Ultrasound Engine with a phased array probe (4.5 MHz) was used to perform standard 10-zone LUS in ten patients with confirmed pulmonary edema, and in five healthy volunteers. The RF data corresponding to each B-mode image and a series of 35 plane wave acquisitions were collected for off-line Doppler, decorrelation, and spectral analyses. B-line thickness and number were associated with peaks of Doppler power at the pleural line. Ten 10 × 5 mm2 5 MHz LUSS, powered by custom-built multiplexed transmit-receive circuit, were fabricated and tested with the same Doppler sequence and signal processing in a lung-mimicking sponge phantom containing variable volumes of water. [Work supported by NIH R01EB023910.]
The successes and failures of flipping an introductory musical acoustics course in response to the COVID pandemic
Authors: Linz Jill A.
Published: November 2021

The advent of COVID-19 brought about many curricular changes throughout the academic world. One of the buzz words that quickly emerged was the idea of a flipped classroom. Just as quickly as we were all zooming, suddenly everyone was flipping their classrooms. A quick check into what this meant revealed itself to have its roots in the ideas of Physics Education Research. Sound & Music is an introductory course in musical acoustics that uses pedagogies based on these methods and has been taught continuously since 1996. The numerous hands-on activities that have been developed for this course were delivered in a specific sequence with two cumulative projects occurring at the end of the semester which focus on instrument design and room acoustics. When COVID occurred, these particular activities posed a big problem. Additionally, having to go remote hampered the format and delivery of the course. All activities and topic ordering had to be rewritten and reimagined. What was needed in the reimaging of the course was a flipping of the topics being taught without compromising the educational experience. Student involvement in the design and implementation of the changes over three semesters was a strong aspect of its overall success.
Acoustics education accelerated by interactive simulators and research imaging system experiments
Authors: Szabo Thomas L. , Kaczkowski Peter
Published: November 2021

Learning acoustics traditionally involves abstract principles, equations and a limited number of specific exercises. We have developed an eight module introductory course in which students can engage with the ultrasound imaging curriculum experientially by interacting with real time GUI-based physics simulators. With only an introduction to the concepts, students with minimal mathematical background can quickly understand how the principles work by varying different simulator parameters over a wide range of examples and observing the output changes. Advanced students who know the simulator equations can learn the subtle interplay of different variables on outcomes on a deeper level. These simulators accelerate learning even more when the equations involve complicated integrals or equations which have to be evaluated numerically. Display options offer different ways of visualizing the acoustic and image data. Laboratories using a Verasonics ultrasound research imaging system provide hands-on learning of signal processing, transducer operation, and image processing.
Penn State acoustic wave (PAW) kits: Development of “at-home” hands-on activities for first-year graduate level acoustics courses
Authors: Russell Daniel A. , Simon Julianna
Published: November 2021

Faculty in the Graduate Program in Acoustics at Penn State have often used in-class physical demonstrations to illustrate acoustic and vibration phenomena when teaching first year graduate students. During the Fall 2020 semester, when physical demonstrations were more difficult due to courses being moved online during COVID-19, we began including open-ended extra credit hands-on problems asking student to use household items to explore fundamental concepts. We observed that students who completed these extra credit experiments showed greater understanding of the material on homework assignments and exams than those who did not. Upon returning to in-person instruction for our first-year graduate courses, ACS 501 (Elements of Acoustics and Vibration) and ACS 502 (Elements of Waves in Fluids), we began developing a set of PAW (PSU Acoustic Wave) Kits that will allow all of our students—both resident and online—the opportunity to enhance their critical thinking in acoustics through inquiry-based learning. These PAW Kits will contain items not commonly found “at home” (masses, springs, dashpots, membranes, accelerometers, short pipes, lapel microphones, etc.), with the goal of at least one inquiry-based activity per major topic. This paper will describe some of the hands-on activities we are developing and testing.
Theoretical and physical insights of acoustic radiation forces beyond Gor’kov potential
Authors: Zhang Likun
Published: November 2021

Acoustic radiation forces exerted on small objects by standing waves can be simply described by the Gor’kov potential that provides a basis for designs of acoustofluidic devices for trapping and separation of particles. However, when considering forces exerted on large objects by general sound beams, theoretical and physical insights into the forces must rely on momentum conservation. Nevertheless, the relative complexity of analysis of the force starting from stress tensor or spatial integral of acoustic radiation pressure creates a barrier on the insights in the frame of momentum conservation. Despite the early availability of momentum conservation frame for acoustic radiation pressure on interface between two media, the insights into acoustic radiation forces on large objects beyond Gor’kov potential are still limited. These insights are now enhanced by our recent theory of momentum conservation frame for three-dimensional acoustic radiations forces. The theory has simplified analytical results for acoustic radiation forces into compact and physically meaningful formulas. These formulas provide an understanding for forces and torques exerted by sound beams on both large objects and interface between two media in various scenarios, which will be summarized and reviewed.
Effect of basset history drag on the accurate determination of streaming flow with PIV measurement
Authors: Zhang Shuai , Orosco Jeremy , Friend James
Published: November 2021

In acoustofluidics, the conflation of acoustic streaming and acoustic pressure effects on suspended particles, especially for particle image velocimetry (PIV) with micron-sized particles, leads to inaccurate streaming measurements. Typical multiphase streaming models fail to account for the Basset history drag, which emerges due to a mismatch between the momenta of the particle and the local flow. The history drag is proportional to a fractional-order derivative of the mismatch. Since this force integrates over time, its absence leads to significant modeling errors while also augmenting errors from other sources (e.g., particle-fluid density mismatch and acoustic radiation forcing). We investigate the effects of particle size selection on accurate streaming flow determination from PIV microacoustofluidic system measurements. We achieve this through experimental observation ofparticle behaviors under varied ultrasonic forcing frequencies (30–500MHz) and particle sizes. We pair the empirical study with an analytical fractional-order differential model of a spherical particle under the influence of radiation forces. Rigorous comparative analyses between the model and observations are undertaken to more completely characterize the magnitude of various effects leading to spurious PIV data. We expect the results of this investigation to clearly delineate optimal PIV particle size selection for the continued study of microacoustofluidic systems.
From macroscale to microscale characterization of droplet breakup regimes using a micromachined ultrasonic droplet generator
Authors: Shan Li , Krippner Kyle , Meacham J. Mark
Published: November 2021

Controllable, uniform droplet generation is critical to many industrial processes and biomedical applications (e.g., materials synthesis, cell handling, and aerosol drug delivery). We have developed an ultrasonic droplet generator that can enable dynamic control over the droplet size distribution in the 2–75 μm range. The system uses a bulk piezoelectric transducer to generate a standing acoustic pressure field that drives fluid transport through an array of microscopic orifices. Our previous work suggests that certain resonances lead to variability in the pressure gradient at the orifices, affecting the droplet size distribution of the resultant spray. Here, we present a parametric study relating ejection uniformity to orifice size, operating frequency, and drive amplitude. We introduce a new system configuration that allows high-resolution stroboscopic imaging of the liquid-gas interface evolution at each orifice. Although the entire micronozzle array remains acoustically active, we use orifice size to control the flow resistance, restricting ejection to a single preselected orifice. Observed ejection regimes resemble classical descriptions of jet breakup (Rayleigh, wind-induced, and atomization), depending on drive voltage. A regime map is created using 5, 10, and 15 μm orifices for 0.5–2.0 MHz actuation from threshold ejection amplitude to the point of chaotic wind-induced breakup.
Acoustic erythrocytometer for mechanical cell probing
Authors: Link Andreas , Sparrow Raymond , Franke Thomas
Published: November 2021

The mechanical properties of cells provide key insights into the type, differentiation and/or pathology of a cell. The mechanical analysis of a cell population, such as a blood sample, enables meaningful biological and medical interpretation for the diagnosis and monitoring of diseases. There are number of diseases which alters the mechanical properties of human red blood cells (RBCs). Here, an acoustic method to probe both the viscous and elastic mechanics of single RBCs by SAW in a microfluidic device is presented. The device operates by exciting a surface acoustic wave in a microfluidic channel creating a stationary acoustic wave field of nodes and antinodes. RBCs are attracted to the nodes and are deformed. Using a stepwise increasing and periodically oscillating acoustic field the static and dynamic deformation of individual red blood cells one by one was studied and the deformation by the Taylor deformation index D and relaxation times were quantified. The precision of the measurement allows to distinguish between individual cells in the suspension and provides a quantitative viscoelastic fingerprint of the blood sample with a resolution of a single cell. The method overcomes limitations of other techniques that provide averaged values and has the potential for high-throughput screening.
Detection and imaging of stress-corrosion cracking in stainless steel using the linear elastodynamics gradient imaging technique
Authors: Remillieux Marcel , Beardslee Luke , Ulrich Timothy J.
Published: November 2021

Linear Elastodynamics Gradient Imaging Technique (LEGIT) is a nondestructive testing technique recently developed to image cracks on the surface of samples. This technique is based on the interaction of an acoustic wave with a crack and the resulting discontinuity in the acoustic wave field such an interaction generates. LEGIT is used to image stress-corrosion cracks in two samples of 304 stainless steel. The first sample is relatively small (50 × 25 × 1.4 mm3) with two mm-size cracks. For this sample, the acoustic source is glued to the sample. The second sample is much larger (180 × 76 × 25.4 mm3), has a curvature, a weld, and multiple cracks running parallel to and across the weld. The imaging of the cracks for this more complex sample is achieved without contact by partial immersion using an underwater acoustic transducer. Imaging data obtained from LEGIT in the two experiments show excellent agreement with a vibro-thermography.
Phonetic convergence in temporal organization during shadowed speech
Authors: Gonzalez Roberto , Clopper Cynthia G.
Published: November 2021

The goal of this study was to examine phonetic convergence in various measures of temporal organization during shadowed speech across different American English dialects. Participants from the Northern and Midland American English dialect regions, as well as “Mobile” participants who had lived in multiple region, read 72 sentences to establish a baseline for temporal organization, and then repeated the same 72 sentences after Northern, Midland, and Southern model talkers. Measures of temporal organization (i.e., %V, ΔC, ΔV, rPVI-C, and nPVI-V) were calculated for the read sentences, shadowed sentences, and model talker sentences. Statistical analysis of the differences in distance between the model talker sentences and the shadowers’ read and shadowed sentences, respectively, revealed significant convergence by all three shadowing groups toward the model dialects for ΔV, and significant divergence by Mobile talkers away from the model talkers for nPVI-V. Though the result of divergence by Mobile talkers was unexpected, both results provide evidence that support previous studies, which claim that social perception is a large contributing factor in convergence and divergence. These results are also consistent with previous findings demonstrating variation across dialects in temporal organization and in addition, provide evidence for variation across dialects in convergence in temporal organization.
Bigger than they appear: Electronic architecture in recording studios
Authors: Berger Russ , Barbar Steve , Schrag Richard , Birney Jon
Published: November 2021

A significant concern for recording in acoustically small spaces is that they often sound zingy, splashy, fluttery or resonant, or (with attempts at treatment) small, choked, dry, and lifeless. Either of these extremes is not conducive to a good recording experience for the performer or the recording engineer. At the same time, variable acoustics has been an elusive goal in small spaces. Passive solutions are generally ineffective, since one’s perception of a small room’s acoustical character is driven primarily by the room volume and the mean free path. Technological advancements in electronic architecture, and specific adaptations of that technology to the challenges of deploying it in small spaces, have made it an affordable application for recording studios. When combined with appropriate natural acoustics, this approach can achieve acoustical results not possible by treatments alone. The apparent volume, surface treatments, and resulting reverberant energy can be modified in real time beyond the constraints of the physical space, both for what the performer experiences within the space, and for what the engineer can capture in a recording. The essential considerations for using electronic architecture in a recording studio are illustrated using examples from recent projects.
Beneficial loudspeaker/room/listener interactions
Authors: Toole Floyd E.
Published: November 2021

Sound reproduction of the highest quality requires an optimized combination of loudspeakers, rooms and listeners—electroacoustics, acoustics and psychoacoustics. Domestic and monitor loudspeakers have improved because of research investigating the physical sounds arriving at listeners in small rooms and correlating double-blind subjective ratings of sound quality with relevant anechoic measurements on loudspeakers. Loudspeakers designed using specific anechoic measurements and guidance (e.g., ANSI/CTA-2034-B) reliably yield high sound quality ratings in double-blind listening tests in normally reflective domestic rooms. The relative subjective ratings of loudspeakers remain substantially unchanged when comparison listening tests are conducted in rooms with very different acoustics, although the absolute sound quality has changed. Listeners clearly adapt to some of the essential perceptual characteristics of rooms. But there are limits. About 30% of subjective ratings of sound quality is attributable to bass quality. This is different for every arrangement of loudspeakers and listeners in every different room. Seat-to-seat variations at low frequencies are large. Absorption is traditionally used to damp bass resonances. However, for reproduced sound, multiple subwoofers, with or without signal processing, can manipulate room resonances. These schemes, with equalization, can substantially attenuate audible resonances while yielding much reduced seat-to-seat variation, using no passive acoustical devices.
An acoustic observatory for sperm whales in the Eastern Mediterranean Sea
Authors: Skarsoulis Emmanuel , Piperakis George , Orfanakis Emmanuel , Papadakis Panos , Kalogerakis Michael
Published: November 2021

A deep-water acoustic observatory for real-time detection and 3D localization of sperm whales has been developed, deployed and operated for 3-month periods in summer 2020 and 2021 off SW Crete in the Eastern Mediterranean Sea. Detection and localization rely on receptions of regular clicks at 3 hydrophones suspended from surface buoys at depths of ∼100 m and ∼1 km apart. Travel times of significant arrivals extracted onboard the buoys are transmitted, together with other supporting data, via mobile broadband to a land-based analysis center where the data from all buoys are combined to enable detection and 3D localization of vocalizing animals exploiting direct and surface-reflected arrivals and using a Bayesian approach. The large separations between hydrophones result in small localization uncertainties for ranges up to ∼6 km, whereas, on the other hand, they pose significant challenges related, e.g., to peak association and synchronization between the buoys. The design and implementation, as well as results from the operation of the system will be presented. [Work supported by Ocean Care – SAvEWhales project.]
Doppler ultrasound observations and metrics of boiling histotripsy treatment progression
Authors: Song Minho , Thomas Gilles P. , Khokhlova Vera A. , Sapozhnikov Oleg A. , Maxwell Adam , Khokhlova Tatiana D.
Published: November 2021

Boiling histotripsy (BH) is a mechanical tissue fractionation method that uses millisecond-long nonlinear HIFU pulses with shock fronts. The BH treatment generates bubbles and tissue debris that move within the liquified lesion due to acoustic radiation force and streaming. Since the velocity of the debris is expected to depend on the lesion size and fractionation completeness, it could provide a quantitative metric of the treatment progression. In this study, the motion of bubble remnants and tissue debris immediately following BH pulses was investigated by high-pulse repetition frequency (PRF) plane-wave color Doppler ultrasound (PRF 9–15 kHz, 50–100 pulses) in ex vivo bovine myocardium and porcine liver. A 256-element 1.5 MHz spiral HIFU array with a coaxially integrated ultrasound imaging probe (ATL P4-2) produced the 10ms BH pulses to create a volumetric lesion in tissue. As tissue liquefaction progressed, the velocity was observed to be directed towards the HIFU transducer, monotonically increased, and then saturated at about 1 m/s. Further, when the lesion was fully liquefied and its axial size was comparable to that of the HIFU focal spot, the motion changed direction to the opposite, with velocity independent of tissue type, consistent with streaming. [Work supported by NIH R01EB7643, R01GM122859, R01EB025187, and RSF20-12-00145.]
In vivo phase aberration correction for high intensity focused ultrasound therapy with a 256-element spiral array
Authors: Thomas Gilles P. , Khokhlova Tatiana D. , Wang Yak-Nam , Totten Stephanie , Schade George R. , Sapozhnikov Oleg A. , Khokhlova Vera A.
Published: November 2021

One of the challenges of transcutaneous high intensity focused ultrasound therapies, especially ones relying on shock formation such as boiling histotripsy (BH), is the deterioration of focusing from phase aberration induced by soft tissue heterogeneities within the acoustic path. Here, a methodology to perform phase aberration correction in vivo is proposed. A custom BH system consisting of a 1.5 MHz phased array of 256 elements connected to Verasonics V1 system was used in pulse/echo mode targeting liver and kidneys in swine. Phase shift on each element needed to correct for aberration was estimated by maximizing the value of the coherence factor on the backscattered signals received from the focal region and iteratively repeating the pulse emission with corrected phases. The process required 3 to 10 iterations to converge to a solution, which necessitated the implementation of tracking the moving target via additional pulse/echo sequences. The performance of the method was evaluated by comparing the transducer driving voltage needed for shock-forming conditions to generate a boiling bubble at the target with and without aberration correction. Results show that aberration correction effectively lowers the voltage required to reach boiling by 8%–25%. [Work supported by NIH R01EB007643, R01GM122859, R01EB25187, P01DK043881, and RSF 20-12-00145.]
Experimental comparison of acoustic backscattered field from a single fiber and media with pseudo-aligned fibers in longitudinal and transverse planes
Authors: Kari Mohammadreza , Rosado-Mendez Ivan , Feltovich Helen , Hall Timothy J.
Published: November 2021

Acoustic backscatter spectrum analyses of soft tissues are being developed to provide quantitative information beyond that offered by B-mode images. Common assumptions used in some approaches are that the medium is homogeneous, isotropic, and produces diffuse scattering conditions. However, in some soft tissues, the presence of fiber-like structures causes the acoustic backscatter to be anisotropic. In this work, we compare the backscattered fields produced by a single fiber, a phantom containing many pseudo-aligned fibers, and biceps muscle. Measurements were performed with single-element immersion transducers using a laboratory benchtop pulse-echo setup, and different linear array transducers on a Siemens Acuson S3000 scanner. The phantom and muscle were imaged in longitudinal and transverse planes to study the effect of fiber orientation on the backscattered field. The results showed that the normalized backscattered power is different in longitudinal and transverse planes. This can result from differences in the sonicated portion of the fibers when varying their orientation with respect to the 3D diffraction pattern. Future work will further study this phenomenon with single fibers and transducers with different focal configurations, and investigate the use of the point-wise signal-to-noise ratio and the generalized spectrum to detect the presence of coherent scattering conditions.
Focus boom simulation benchmark cases for the 182nd ASA Meeting May 2022
Authors: Rallabhandi Sriram , Page Juliet A. , Carrier Gerald
Published: November 2021

The low-boom prediction committee comprised of several research agencies and companies across the world plans to organize a special session dedicated to prediction and comparison of focused sonic booms. This presentation will document and discuss the benchmark cases that will be studied and compared during this special session. The case description would include the underlying near-field CFD data along with relevant flight conditions and mission trajectory information for the participants to simulate and discuss their individual focus boom predictions. Details of the CFD simulation conditions and solution procedure to obtain off body pressure waveforms on a cylindrical surface around the aircraft at a few selected points along the flight trajectory will be provided. The rationale for the choice(s) of the mission trajectories to result in focus booms near the ground for comparison using multiple independent implementations will be provided as well.
Acoustic and thermal numerical modelling of transcranial ultrasound thermal therapy
Authors: Drainville Andrew , Moore David , Snell John , Chatillon Sylvain , Padilla Frederic , Lafon Cyril
Published: November 2021

Ultrasound has long been recognized as a therapeutic tool with potential to treat disorders throughout the brain. However, the attenuation and distortion of acoustic waves caused by the skull has been a significant challenge to the development and clinical application of transcranial ultrasound therapies. Numerical models, such as the use of finite difference method, can be prohibitively expensive in required computational resources. While some numerical models can be computationally prohibitive, the ray-tracing modelling method used in the CIVA Healthcare simulation platform has been shown to be an efficient and computationally inexpensive method of modelling transcranial focused ultrasound, and can be coupled to Pennes’ bioheat transfer equation to model temperature in biological tissue. The present work quantifies the sensitivity of transcranial ultrasound to clinically relevant uncertainties in the physical properties of the skull (i.e., shear conversion, wave speed), and combines the ray-tracing acoustic model with a numerical thermal model to provide a versatile and unified software platform for use in clinical ultrasound treatment planning. Results are compared with experimentally measured thermal rise from transcranial focused ultrasound using a clinical Insightec ExAblate 650 kHz 1000-element system, and shown to exhibit a high degree of accuracy. [This work is supported by the Focused Ultrasound Foundation.]
Electric vehicle additive sounds: Detection results from an outdoor test for sixteen participants
Authors: Roan Michael , Neurauter Luke , Beard Michael , Miller Marty
Published: November 2021

Electric vehicles are significantly quieter than standard internal combustion engine vehicles. Although this is a benefit to the acoustic soundscape, it presents a safety concern, particularly to the vision impaired. Because of this, governments around the world have mandated that artificial sounds be added to electric vehicles in order to improve pedestrian safety. In the United States, these regulations are embodied in a National Highway Transportation Safety Administration document, FMVSS-141. This document provides guidance on the 1/3 octave-band frequency content, overall SPL, and measurement procedures that must be followed for a vehicle to be certified. This talk will present the results of a listener test with 16 participants who pressed a button upon detection of an approaching vehicle equipped with a FMVSS-141 compliant additive sound. Results are presented at probability of detection versus distance. This provides a unique view of the effectiveness of these sounds and additional aspects of this problem such as additive sound contribution to noise pollution and listener false alarm rates. Lastly, the talk will cover difficulties with this type of outdoor testing and recommendations for conducting them in a virtual environment.
Pinhole measurements of hydroacoustic pressure fluctuations beneath wall-bounded turbulent flows
Authors: Kim Jane H.
Published: November 2021

The common flush-mounted-transducer measurement method for underwater surface pressure fluctuations results in transducer-size-limited spatial resolution, which may be inadequate for the fluctuations produced beneath a turbulent boundary layer (TBL). For water moving over a smooth surface at speeds of a few meters per second, the relevant length scales may be less than 100 mm with fluctuation magnitudes far less than 1% of the free-stream dynamic pressure. Unfortunately, such size and sensitivity requirements cannot simultaneously be met with common instrumentation. However, mounting microphones behind pinholes is a possible solution for wall-bounded airflows. This presentation covers the effect of pinhole mounting pressure transducers for measuring surface pressure fluctuations in wall-bounded turbulent flows in water. The experimental work is conducted in a turbulent channel flow at varying flow speeds (0.5 to 7 m/s) using pressure transducers with a 5-mm-diameter sensitive area that are flush mounted and mounted behind variable size pinhole openings. The measured pressure-fluctuation power spectra are compared to each other and to results from past direct numerical simulations, in the 10 Hz to 10 kHz frequency range, to determine the utility of pinhole mounting for underwater TBL pressure-fluctuation measurements. [Sponsored by ONR.]
Preliminary results from a time domain model of a clarinet-like system
Authors: Thompson Stephen C.
Published: November 2021

A time domain model of a clarinet-like system has been built using the Simscape multidomain modeling system. This model largely replicates physical features that have been included in previous models by others. The air column has constant inside diameter. The tube has thirteen tone holes. The first three holes are spaced to give approximate chromatic tone spacing. The remaining holes have the same spacing as the last chromatic pair, and all the holes are sized to give a constant tone hole lattice cuttoff frequency of 1500 Hz. The reed is modeled as a single degree of freedom oscillator that terminates the “closed” end of the tube. Blowing pressure is provided by a mouth cavity of fixed volume. This model allows calculation transient behavior that becomes steady state if the input pressure remains constant. We present results of startup transients, slow crescendo and decrescendo playing, and oscillation behavior in response to opening and closing the tone holes. The current model does not accurately match the design of any particular instrument, but it does demonstrate an ability to calculate the behavior of some interesting playing behaviors of an instrument.
Acoustic scene modeling for echolocation in bottlenose dolphin
Authors: Cheong YeonJoon , Shorter K. Alex , Popa Bogdan-Ioan
Published: November 2021

The biosonar of bottlenose dolphins has been shown to have excellent target discrimination performance in cluttered environments, but how the animals process the flow of information used in their adaptive searching process is still an open question. In this work, we present a physics-based model of the process echolocating dolphins may use during target discrimination tasks and validate the model with experimental results. Assuming that dolphins emit biosonar clicks and continuously compare the return echoes with learned representations of echoes from familiar objects, we define a likelihood parameter, a metric that quantifies this comparison. We show that the dolphins’ adaptive search behavior during echolocation can be interpreted as an effort to maximize the likelihood parameter. Our model is validated experimentally using target discrimination tasks in which a dolphin correctly/incorrectly located a given target in the presence of distraction objects in an open lagoon while it was wearing eyecups. The results show that the dolphin positioned itself where the likelihood parameter was maximized demonstrating that our model explains well the dolphin’s behavior during the tasks. [Work supported by the Department of the Navy Grant No. N00014-18-1-2069.]
You keep using that term, I do not think it means what you think it means: variable-air-volume terminal box catalog noise criteria data and what AHRI Standard 885 really says
Authors: Manley David , Pippitt Logan
Published: November 2021

Mechanical Engineers often include Noise Criteria data on equipment schedules for variable-air-volume terminal boxes. This can lead to confusion when acousticians recommend noise control interventions, as the catalog data leads the Engineer to believe they have selected appropriately quiet equipment. This session will review how Noise Criteria catalog ratings are determined according to AHRI Standard 885 and compare the Standard assumptions versus real world designs. Multiple design cases will be presented to show the pitfalls of relying on equipment catalog Noise Criteria ratings.
Surface manipulation of elastic half-space to suppress Rayleigh wave propagation: A step towards boundary condition-based meta-surface design
Authors: Pillarisetti Lalith Sai Srinivas , Lissenden Cliff , Shokouhi Parisa
Published: November 2021

A boundary condition (BC)-based design methodology for metasurfaces was recently proposed to control low-frequency Lamb waves in a plate. This study highlights the significance of a type of Cauchy BCs, called Mindlin BCs, for controlling Rayleigh wave propagation and provides motivation for a BC-based metamaterial design for surface wave control. Analytical study on an elastic half-space with Mindlin BCs reveals no possible surface wave solutions. The frequency-domain and time-domain simulations by imposing Mindlin BCs on the surface in the path of Rayleigh wave propagation are consistent with analytical predictions exhibiting no surface wave transmission. The simulation results reveal mode conversions from Rayleigh wave to bulk waves directed into the half-space and a low amplitude Rayleigh wave reflection. For a finite-sized Mindlin BC patch, a portion of mode-converted bulk waves near the surface converts back to Rayleigh waves at the end of the BC patch suggesting the requirement of a minimum Mindlin BC patch length for effective suppression of surface waves. Finally, we show that frequency-dependent Mindlin BCs are imposed by an array of rod-like resonators resulting in a surface wave bandgap. These findings provide new insights into designing novel metasurfaces that provide the necessary coupling for desired surface wave control.
Predicting children's audiovisual speech recognition thresholds based on unimodal performance
Authors: Lalonde Kaylah
Published: November 2021

This study examined the extent to which individual differences in children’s audiovisual speech recognition thresholds are explained by their performance in unimodal auditory and unimodal visual conditions. Auditory-only and audiovisual speech recognition thresholds were measured in fifty children between 7 and 9 years of age using an adaptive closed-set speech recognition task in a two-talker speech masker. Children heard color-number combinations and responded by choosing the color-number combination on a touch-screen monitor. Visual-only speech recognition accuracy scores were measured using the same stimuli and closed-set response format. Correlations and linear modeling were used to examine the extent to which visual-only speech recognition accuracy, auditory-only speech recognition thresholds, and age predict audiovisual speech recognition thresholds. Audiovisual speech recognition thresholds were positively correlated with auditory-only speech recognition thresholds and negatively correlated with visual-only accuracy. A linear model explained 38% of variance in audiovisual thresholds and indicated that children with better visual-only accuracy had lower audiovisual thresholds. Effects of auditory-only accuracy and age were non-significant. These results suggest that lipreading ability contributes to individual differences in 7- to 9-year-old children’s audiovisual recognition of color-number stimuli in a two-talker speech masker.
Experimental results on acoustic communication channels in pipelines
Authors: Zhang Erjian , Abdi Ali
Published: November 2021

Transmission of information and data through pipelines using acoustic waves is a useful and practical approach in remote sensing, telemetry and monitoring applications. The data to be transmitted is first modulated by an actuator on acoustic waves, to travel through the body of the pipeline. At the receiver side, strain sensors and triaxial accelerometers can be used to receive and demodulate the data [E. Zhang and A. Abdi, “Communication rate increase in drill strings of oil and gas wells using multiple actuators,” Sensors 19 1337 (2019)]. Understanding the characteristics of the strain and acceleration communication channels in pipelines is of interest, for effective communication and telemetry system design. In this paper, we use the data measured by the strain and triaxial accelerometer sensors, to study several essential communication characteristics of the strain and acceleration channels in pipes, such as frequency responses, possible correlations among different channels, and signal-to-noise ratios of different channels. Results of this study are useful for proper design and optimization of acoustic communication and telemetry systems operating through pipelines. [The work is supported in part by NSF.]
Peak-time sensitivity kernels for noise cross-correlation patterns
Authors: Cornuelle Bruce , Skarsoulis Emmanuel
Published: November 2021

Sensitivity kernels for travel-time observables defined on the noise cross-correlation pattern – the envelope of the cross-correlation function of the underwater noise field between two locations – with respect to changes in the sound-speed field in refractive underwater environments will be addressed. A wave-theoretic scheme allowing for finite-frequency calculations in 2 and 3 dimensions combined with the Born approximation for perturbations of the Green’s function and the peak-arrival approach is used to obtain peak-time sensitivity kernels (PTSKs) with respect to environmental (sound-speed) changes. PTSK results for different propagation conditions and noise-source distributions, ranging from spatial distributions of uncorrelated noise sources to point sources such as individual ships, will be presented. The PTSKs can be a useful tool for obtaining environmental information from noise measurements. [Work supported by the Office of Naval Research.]
Finding each other: Achroia grisella’s oddly simple directional ear
Authors: Díaz-García Lara , Reid Andrew , Jackson Joseph , Windmill James
Published: November 2021

Achroia grisella is a pyraloid moth capable of directional hearing. It is generally accepted that hearing arose in moths to avoid bats, their main predators, and, in this particular case, was later repurposed into a rudimentary mating tool. The male emits ultrasonic signals of a wavelength several times larger than the distance between their tympana during its mating process. Notwithstanding, the female moths are capable of somewhat efficiently reaching the males after some zigzagging. Another remarkable feature is the simple structure of the ear, consisting of a cluster of just four receptor cells attached directly to the tympanic membrane. Moths with only one functioning ear have been seen to reach the males still, which implies the tympanum structure itself must confer the moth with monoaural directionality. A model is developed in COMSOL to explain the behavior of the moth ear. The complexity of the model is increased by improving the resemblance to the natural one, starting from a circular plate and progressing to, eventually, a damped elliptical plate with two different thicknesses and an attached point mass.
Novel software for deep-learning based acoustic data analysis
Authors: Frazao Fabio , Bergner Steven , Dowd Mike , Joy Ruth , Kirsebom Oliver S. , Nguyen Hong Duc Paul , Padovese Bruno , Randon Marine , Riera Vuibert Amalis , Sakib Sadman , Veirs Scott , Veirs Val , Wladichuk Jennifer , Yurk Harald
Published: November 2021

In recent years, deep neural networks have been successfully applied to solve a range of detection and classification tasks in underwater acoustics, outperforming existing methods. However, deep learning models are “data hungry” requiring large amounts of accurately labelled acoustic samples to train. Moreover, a certain amount of “fine tuning” is often required to achieve satisfactory performance in a new acoustic environment. Thus, the development of deep learning models depends on the input of expert human analysts, both for building the initial training set and for adjusting the model's performance. However, open-source software to facilitate this collaboration between machine learning developers and acousticians is currently lacking. To address this need, our team is building a web-based application for collaboratively annotating sound samples and validating model predictions. The user interface is designed to be familiar to acousticians, while machine learning developers have access to a dashboard allowing them to efficiently leverage the acousticians' expert knowledge. In this contribution, an overview of the application will be given and its functionalities will bedemonstrated through its application to the HALLO (Humans and ALgorithms Listening for Orcas) project. Future developments will also be described, highlighting complementary applications under development such as a model adaptation tool.
Capabilities and features of the “HIFU beam” nonlinear modeling tool for axially symmetric acoustic fields generated by focused therapeutic transducers in layered media
Authors: Yuldashev Petr V. , Karzova Maria M. , Kreider Wayne , Rosnitskiy Pavel , Sapozhnikov Oleg A. , Khokhlova Vera A.
Published: November 2021

The goal of this introductory talk is to present an overview of the software termed “HIFU beam” that has been designed for simulating HIFU fields generated by axially symmetric single-element transducers and annular arrays in flat-layered media that mimic biological tissues. Numerical models include the Khokhlov–Zabolotskaya–Kuznetsov (KZK) and one-way Westervelt equations with thermoviscous absorption as well as power-law absorption to capture frequency-dependent effects. The numerical algorithms include combinations of time- and frequency-domain finite-difference schemes to simulate formation of high-amplitude shocks at the focus. The software comprises a MATLAB toolbox combined with a user-friendly graphical interface and binary executable compiled from FORTRAN source code; it is available for Windows operating systems only. Simulation examples representing typical cases of ultrasound transducers, focusing conditions, and propagation in layered media are presented to illustrate software features for High Intensity Focused Ultrasound (HIFU) applications. The software tool “HIFU beam” is freely available and can be downloaded, along with a detailed help file, from the website http://limu.msu.ru. The software can help to predict nonlinear HIFU pressures generated by existing transducers and help in the design of transducers for achieving specified acoustic outputs. [Work supported by RSF 20-12-00145, NIH R01EB7643, and R01EB25187.]
Acoustic micro-tapping optical coherence elastography (AuT-OCE) to quantify biomechanical changes following corneal collagen crosslinking: Ex vivo study
Authors: Kirby Mitchell , Pelivanov Ivan , Pitre John , Wallace Ryan , O'Donnell Matthew , Wang Ruikang K. , Shen Tueng T.
Published: November 2021

In degenerative corneal diseases, such as keratoconus, local deterioration in mechanical properties results in corneal deformation and vision loss. Collagen cross-linking (CXL) has been used to delay progression of keratoconus with some success in slowing the disease, both long-term and immediate outcomes remain unpredictable for each patient. There is a clear unmet clinical need to develop a personalized biomechanical model based on quantitative maps of corneal mechanical moduli to quantify both biomechanical properties and predict final corneal shape. In this study, we use a novel non-contact, non-invasive AuT-OCE method to quantify corneal elasticity. Because of the anisotropic corneal property due to its collagen structure, a nearly incompressible transversely isotropic (NITI) model was developed to characterize its elasticity. It has been shown that in-plane tensile and out-of-plane shear properties are defined by different moduli, E and G, respectively. Both E and G experienced significantly different stiffening responses to CXL. The increase in G relative to E suggests that while CXL strengthened the tensile strength of the tissue, the ability of the cornea to resist shearing forces was more dramatically altered. AmT-OCE appears capable of changing diagnostic criteria of ectatic corneal diseases, leading to early diagnosis and more precise surgical planning.
Treatment of neovascularization in the eye by photo-mediated ultrasound therapy
Authors: Yang Xinmai , Paulus Yannis , Wang Xueding
Published: November 2021

Neovascularization in the eye is a common disorder. Abnormal microvessels can develop in the cornea, retina, or choroid of the eye, leading to severe vision loss if left untreated. Current treatment methods carry disadvantages or side effects, such as drug-resistance or damage to the surrounding healthy tissues. By applying synchronized laser pulses and ultrasound bursts, we developed a technique, termed photo-mediated ultrasound therapy (PUT), as a localized antivascular method based on the enhanced cavitation mechanism. PUT takes advantage of the high native optical contrast between blood and surrounding tissues, and has the unique capability to self-target microvessels without damaging surrounding tissues. The technique utilizes nanosecond laser pulses, which is spatially and temporally synchronized with low duty-cycle ultrasound bursts of sub-MHz frequencies at the targeted microvessels. We have tested the feasibility of PUT on the removal of neovascularization in the cornea, retina and choroid in a rabbit eye model. We found that neovascularization in the eye could be greatly reduced after PUT, and the occlusion of microvessels could last up to 4 weeks. In conclusion, PUT holds significant promises as a non-invasive method to precisely remove microvessels in neurovascular eye diseases by more selectively treating vasculature with minimized side-effects.
Non-contact acoustic micro-tapping optical coherence elastography (AμT-OCE) in the cornea: Mechanical model, ex vivo and in vivo results, and direct comparison with mechanical tests
Authors: Pelivanov Ivan , Kirby Mitchell , Kuriakose Maju , Liou Hong-Cin , O'Donnell Matthew , Wang Ruikang K. , Shen Tueng T.
Published: November 2021

The cornea is one of the primary determinants of visual performance. Its highly pressurized anisotropic structure of collagen fibrils embedded in a hydrated proteoglycan matrix forms the clear refractive primary lens of the eye. Despite recent success in corneal topography, there are no clinical tools to predict shape changes from vision-correction therapies such as LASIK and CXL due to the absence of non-contact methods that can map corneal elasticity in vivo. Here we review our newest results in quantification of corneal elasticity. Recently, we produced a technology combining non-contact excitation of sub-mm wavelength mechanical waves in the cornea using air-coupled acoustic micro-tapping (AμT), with 1.6 MHz scan-rate phase-sensitive OCT to track their propagation three-dimensionally in real time. However, corneal moduli reconstruction from measured wavefields requires an anisotropic elastic model and cornea’s bounded, non-flat geometry must be taken into account. Thus, a nearly incompressible transversally isotropic (NITI) model of corneal elasticity was developed. We have performed multiple ex vivo and in vivo studies in rabbit, porcine and human corneas and compared AμT-OCE results directly with conventional mechanical tests (tensile extensometry and shear rheometry). These studies demonstrate that in-plane Young’s and out-of-plane shear moduli can be accurately mapped with non-contact, non-invasive AμT-OCE.