bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatio-temporal evaluation of anti-biofilm cavitation activity by passive acoustic mapping
Authors: Keller Sara , LuTheryn Gareth , Gray Michael , Stride Eleanor P. , Cleveland Robin O. , Coussios Constantin
Published: November 2022

Bacterial biofilms present a major challenge to achieving effective antibiotic therapy, as these sessile communities of microbes confer protection to bacteria by decreasing antibiotic efficacy. Focused ultrasound can mechanically disrupt biofilms, offering a new ‘drug-free’ antibiotic paradigm. The goal of this work is to validate, quantify, and optimize the role of acoustic cavitation in the biofilm disruption process through spatiotemporal monitoring of cavitation activity. A clinical isolate strain of Staphylococcus aureus from native valve endocarditis was cultured for 72 hours within a flow channel to form a biofilm. A 1.1 MHz spherically focused transducer was used to expose the biofilm from below at a 45° angle. The in situ acoustic field was characterized with a fibre-optic hydrophone. A calibrated 5–11 MHz linear array was placed 25 mm above the biofilm in order to record acoustic emissions during biofilm disruption from which passive acoustic maps of cavitation could be derived. Biofilms were exposed to 4.5 MPa peak rarefactional pressure (derated), 10,000 cycles, at a 1 Hz PRF. Qualitative reduction of biofilms was assessed by live/dead staining with Syto 9/propidium iodide, which was correlated with cavitation activity observed in the passive acoustic maps.
Characterization and monitoring of cavitation behavior induced by a dual-mode pulsed high-intensity focused ultrasound array
Authors: Williams Randall P. , Khokhlova Vera A. , Kreider Wayne , Sapozhnikov Oleg A. , Khokhlova Tatiana D.
Published: November 2022

Pulsed high-intensity focused ultrasound (pHIFU) is capable of inducing cavitation in tissue without the need for contrast agents, thereby enhancing permeability and passive drug penetration in tissue with poor perfusion. We have developed and characterized the performance of a 64-element linear ultrasound array for image-guided therapy, capable of generating sufficient levels of inertial cavitation at 1 MHz, along with B-mode and Doppler imaging for targeting and cavitation assessment, respectively. Cavitation behaviors induced by different pHIFU exposures were investigated using high-speed imaging in agarose and polyacrylamide phantoms in conjunction with passive cavitation detection (PCD) and plane wave Doppler imaging. Image quality assessment was performed on in vivo porcine models, and cavitation monitoring was demonstrated on ex vivo tissues. High-speed images of the induced cavitation behavior while steering the beam focus both axially and laterally (within ±1.2 cm) were in agreement with Doppler power distributions and broadband noise emissions from PCD. Destructive cavitation behaviors in both gels and tissue were induced at relatively low peak-negative pressures (3–4 MPa), provided that the pHIFU focal waveform was nonlinearly distorted. B-mode image quality is sufficient for recognizing the relative position of anatomic landmarks and targeting cm-sized regions. [Work supported by NIH grants R01EB023910 and R01EB025187.]
Bubble-cloud characteristics and ablation efficiency in dual-frequency intrinsic threshold histotripsy
Authors: Edsall Connor W. , Huynh Laura , Hall Timothy L. , Vlaisavljevich Eli
Published: November 2022

Intrinsic threshold histotripsy has been shown to nucleate bubble clouds and generate ablation closely matching the dimensions of the focal region above the intrinsic threshold (∼25–28MPa) with the ablation efficiency dependent upon the size and density of bubbles within the cloud. This work investigates the effects of dual-frequency histotripsy pulsing on bubble-cloud characteristics and ablation efficiency. Histotripsy was applied to agarose tissue phantoms (1%) using a dual-frequency 500kHz–3MHz array transducer with equal pressure delivered by each frequency. The arrival time of the 3 MHz pulse was varied relative to the 500 kHz pulse, and high-speed imaging was used to characterize the bubble-cloud dimensions, bubble density, and individual bubble size. Ablation was determined using red blood cell phantoms. Results indicated that dual-frequency pulsing generated bubble clouds with intermediate cloud size, bubble size, and bubble density compared to single-frequency (500 kHz and 3 MHz) pulsing, with these characteristics further modulated by the respective pulse arrival times. Additionally, dual-frequency pulsing increased ablation efficiency compared to previously published single frequencies (500 kHz and 3 MHz) with the most efficient ablation observed for cases where the 3 MHz pulse arrived at the leading edge of the 500 kHz pulse. Overall, this investigation demonstrates possible benefits of dual-frequency histotripsy pulsing, warranting further investigation.
An implementation of a finite difference time domain method for second-order nonlinear acoustic equations
Authors: Dunn Kyle G. , Muhlestein Michael B.
Published: November 2022

The framework of the numerical scheme presented in this talk is that of the finite-difference time-domain (FDTD) method published by Sparrow and Raspet [J. Acoust. Soc. Am. 90, 1991]. The method is fourth-order in space and second-order in time when propagating in homogeneous media. Our implementation resides in a Cartesian coordinate system and is meant to be used in inhomogeneous media. In the neighborhood of inhomogeneities the FDTD method is reduced to second-order in space. Of interest to our applications is the simulation of infinite domains, which is achieved using the perfectly matched layer (PML). The particular PML implementation we consider is one that was designed to absorb linear acoustic waves neglecting thermoviscous effects. In this talk, we will give an overview of our FDTD implementation and show one- and two-dimensional examples to illustrate performance in heterogeneous media that include changes in material properties and scattering objects.
Finite difference time domain ray-based modelling of acoustic scattering for target identification and tracking
Authors: Eastland Grant
Published: November 2022

The Finite Difference Time Domain (FDTD) method has provided a powerful technique for modelling and simulation of solutions of a variety of acoustics problems. The purpose of this investigation is to present work on the development of time-domain models of acoustic scattering from targets near a flat pressure-release boundary for use in identification and tracking from a moving receiving platform. The timing from acoustic source to reception are dependent on the location dependent sound speed profile and the specular scattering points on the target. There can be multiple specular points revealed on the target because of interactions with the flat boundary; each of which are modelled utilizing the FDTD method providing path corrections due to variation in propagation brought on by the sound speed profile of the environment.
Impact of industrial partnerships in the acoustics program at Kettering University
Authors: Stiles Timothy A. , Kumon Ronald E. , Ludwigsen Daniel
Published: November 2022

Kettering University has an experiential learning model in which students typically alternate between academic and cooperative work terms every quarter during their entire undergraduate degree program. In this approach, industrial partners play a particularly critical role. In this talk, we will discuss how partnerships with industry have impacted our classroom experiences and inspired curricular elements that incorporate theoretical, computational, and experimental approaches to solve problems in acoustics. We will highlight some of the work related to acoustics that students have done in their co-op projects and how students have served as a bridge between the academic and corporate environments. The course “Acoustics in the Human Environment” has recently benefited from a grant from the Head Acoustics Foundation. The course was revamped in Spring 2022 to include more detailed analysis and a jury study that make use of this donation. The course “Acoustic Testing and Modeling” uses Siemens Simcenter Testlab to acquire experimental data and Comsol for computer simulations. Recently, this course has added a module on Laser Doppler Vibrometry that makes use of equipment from Polytec. The efforts in these courses have enabled students to be better prepared for acoustic testing projects for a thesis or co-operative employment terms.
Experiments on the nonlinear interaction of crossed turbulent streaming jets: A case study in mentorship
Authors: Cartron Jenna M. , Korman Murray S.
Published: November 2022

During (2017–2018) co-author JMC began a mentorship at USNA as a HS senior. Projects led to developing an apparatus to study the interaction between crossed turbulent streaming jets in water. The ISNA 21 (Santa Fe) was an opportunity to present this research – which included a live demonstration. See [Proc. Mtgs. Acoust. 34, 045022 (2018)]. Majoring in material science at JHU, JMC worked as a college intern at USNA (during 4 summers) to further develop the turbulent streaming jets experiment which now included a LaVision 2-D PIV (particle imaging velocimeter). Home-made MOSFET power amplifiers, Langevin 28 kHz ultrasonic transducers and aluminum stepped horns, were replaced by kits developed by Sonics & Materials. The kits including 40-kHz oscillators, 20 Watt amplifiers, impedance matching to the 40 kHz transducers CV245 and titanium 1/2, 1/4 and 1/8 inch diameter stepped horns Part # 630-0594 – to generate stronger downward East and West crossed turbulent jets (at a 60 deg angle) in an open 10 cc acrylic tank. As a by-product, cavitation bubbles allow flow visualization. Lighthill’s nonlinear theory of acoustic streaming (1978) for a single source will be discussed including “Stuart streaming,” Reichardt and Schlicting’s (turbulent jets) and Squire’s theory on nonlinear laminar jet flow.
Penn State ASA student chapter educational workshops in engineering design tools for loudspeaker and amplifier system design
Authors: Riccardi Peter J. , Rusk Zane T. , Case John A. , Park Heui Young , Rokni Eric
Published: November 2022

Hands-on workshops and projects are an effective way to provide meaningful and memorable STEM education. To promote practical acoustics and engineering knowledge, the Pennsylvania State University Acoustical Society of America student chapter hosted a series of workshops wherein students learned the basics of electroacoustic transduction, mechanical modeling, electronics design, and PCB routing. This educational effort was accomplished by sponsoring a three-way loudspeaker design project. Transduction topics were covered by optimizing the model of a ported woofer in MathWorks SimScape, using the recently developed Acoustical Domain for Simscape available from MATLAB central. Mechanical modeling of the three-way speaker cabinets to produce manufacturing drawings was covered in SolidWorks workshops. Finally, the basics of circuit design, schematic capture, and PCB routing were covered in DipTrace through the design of a stereo integrated amplifier with an active crossover that was built to power the loudspeaker. Details about the workshops and performance of the designed components will be presented.
Open-source acoustics simulation in the education environment
Authors: van der Harten Arthur W.
Published: November 2022

Pachyderm Acoustic Simulation is a professional tool for geometrical and numerical simulation of acoustics in the built environment that happens to be open source under the General Public License. Over the course of the 14 year life of the open-source acoustics simulation project, Pachyderm Acoustic has had the privilege of partnering with numerous academic institutions worldwide to educate architecture and engineering students in acoustics. This has been in the form of support for student projects, lectures and workshops on acoustics simulation and other topics, and, in some cases, PHD advice. This session will explore several notable examples of successful pedagogy using the open source software as a tool for higher education. There will also be some discussion of approaches to pedagogy that have not been as successful, in an effort to further discussion regarding an appropriate approach to higher learning in acoustics.
Microphone location investigation for standard aircraft ground run-up noise measurements
Authors: Wall Alan T. , Campbell Steven C. , Mobley Frank S.
Published: November 2022

The correct placement (height, orientation, and mounting techniques) for microphones used in standard data collection practices for aircraft environmental noise models is a topic of debate. Previous studies have demonstrated and quantified the dependence of spectral data recorded as a function of microphone placement variations and relative source origin. In this work, an in-depth investigation of microphone mounting effects is performed with an emphasis on (1) microphone height and (2) ground-mounting configuration for the purpose of quantifying ground run-up aircraft noise emissions for environmental noise model generation. Data for this investigation were collected on the T-7A Red Hawk in both standard (see ANSI S12.75-2012) and off-standard configurations for comparison.
Brillouin light scattering spectroscopy as a versatile probe of hypersound in diverse materials systems
Authors: Hanlon Dillon F. , McNiven Bradley D. , Spencer Stephen J. , Andrews G. T.
Published: November 2022

An overview of the inelastic laser light scattering technique of Brillouin spectroscopy and its application to the study of hypersound in a diverse set of materials systems will be presented. In particular, results obtained from recent Brillouin scattering experiments on natural gastropod mucus, layered high temperature superconductor Bi2Sr2CaCu2O8+δ, biotite micas, and satellite tobacco mosaic virus crystals will be highlighted. Collectively, these results demonstrate the utility of Brillouin light scattering spectroscopy as a sensitive non-destructive probe of hypersound velocity and attenuation in the vicinity of structural phase transitions, the influence of chemical composition and incommensurate structure on material elasticity, and of phonon dynamics in challenging materials classes.
Three-dimensional characterization of spatial sound fields via acousto-optic sensing
Authors: Verburg Samuel A. , Williams Earl G. , Fernandez-Grande Efren
Published: November 2022

Characterizing audible sound fields over space is at the core of many applications in acoustics and audio technology, including active sound field control, spatial audio, and the experimental analysis of sound radiation. For this purpose, arrays of microphones are commonly deployed across the sound field, with an inter-microphone spacing that depends on the highest frequency studied. Capturing sound fields at mid and high frequencies is nonetheless challenging, as the number of transducers required becomes impractically large and the scattering of sound introduced by the array is often significant. Acousto-optic sensing enables the remote and non-invasive characterization of acoustic fields, and thus it represents an attractive alternative to conventional electro-mechanical transducers in several applications. The phase-shift that laser beams experience as they travel through a pressure field are measured via optical interferometry. The optical measurements are then used to reconstruct the field that originated such phase variations. In this study, we project the measured data into a set of functions suitable to represent sound fields over space. The projection makes it possible to improve the reconstruction accuracy and extrapolate the reconstruction outside the measured region. We demonstrate the method by reconstructing the three-dimensional sound field inside a room using optical data.
Measurement of airborne ultrasound using laser Doppler vibrometry
Authors: Liu Zihuan , Vatankhah Ehsan , Meng Yuqi , Niu Xiaoyu , Hall Neal A.
Published: November 2022

The speed of light in air is dependent on the air's instantaneous density. Since air density is modulated by sound, sound in the air can be observed and measured using optical methods. One such optical method is Laser Doppler Vibrometry (LDV). Most commonly, LDVs measure the mechanical velocity of a surface. However, by placing a rigid reflector beneath a sound beam in air, it is possible to measure the time rate-of-change of optical refractive index and thus to measure dynamic changes in air density, or sound. In prior demonstrations, this method has been used to visualize sound fields in the audible frequency range and ultrasonic range underwater. Here, we present the first measurements of high-intensity airborne ultrasound beams in the frequency range spanning 100 kHz–300 kHz. We observe accumulated distortion, wave steepening, and weak shock formation as high intensity sound beams propagate. LDV measurements are compared against numerical simulations of the sound field. Advantages of the LDV technique are discussed, and we also attempt to quantify limitations of the technique which include spatial averaging of the measurand along and normal to the optical beam path.
Optical fiber tip damage by sparks in holmium:YAG laser lithotripsy
Authors: Pishchalnikov Yuri A. , Behnke-Parks William M. , Stoller Marshall L.
Published: November 2022

Laser lithotripsy disintegrates urinary stones using laser pulses delivered to the stone via an optical fiber. The fiber tip is frequently damaged during the procedure, but the mechanism of damage is not understood. Here we show that the free-running long-pulse (>150 μs) infrared holmium:YAG lasers that currently are most often used for laser lithotripsy can produce sparks and shock waves, which is an unexpected result as the optical breakdown is typically observed with more powerful Q-switched lasers. We used an ultrahigh-speed camera Shimadzu HPV-X2 at frame rate up to 10 million frames per second to record single laser pulses with 242-μm glass-core-diameter fibers in contact with whole surgically retrieved urinary stones, BegoStones, and hydroxyapatite-coated glass slides in air and water. Fiber-tip damage occurred even without cavitation and was greater at 1.0 J than at 0.6 J (p = 0.010). No fiber-tip damage occurred without sparks (1.0 J, 500 pulses, water). Shock waves produced by sparks and subsequent collapses of vapor bubbles could break optical fiber tip in a single laser pulse. These observations suggest that the previously unappreciated optical breakdown with the free-running holmium:YAG lasers can be responsible for fiber-tip damage in laser procedures. [Work supported by NIDDK of NIH under award R43DK129104.]
Imaging acoustic phenomena with transmission electronic speckle pattern interferometry
Authors: Moore Thomas R.
Published: November 2022

Optically imaging acoustic phenomena requires sensing the pressure-induced change in index of refraction of the medium, and imaging this change in index has been accomplished in the past using a variety of methods. However, these methods typically require a static ambient atmosphere, the sensing area is often limited by the size of the optics, and in some cases the phenomena of interest must be either reproducible or stable for time periods exceeding tens of minutes. We demonstrate that transmission electronic speckle pattern interferometry (TESPI) is a fast and effective method for imaging gas flow, acoustic standing waves, and standing waves in the presence of flow, with sensing times of less than one second and a viewing area of a square meter or more. [Work supported by NSF grant No. PHY–2109932.]
An acoustic examination of English fricative production by Korean- and Farsi-English bilinguals: The role of language- and orthographic-specific effects
Authors: Rafat Yasaman , Spinu Laura , Whitford Veronica , Joanisse Marc , Trivedi Vidhi , Swiderski Natasha , Valdivia Celina , Cornwell Sarah , Mohaghegh Mercedeh
Published: November 2022

Recent work has shown that exposure to orthographic effects can promote first-language (L1) phonological transfer. However, it is relatively unknown whether orthographic effects persist in highly proficient bilinguals. Here, we examined how L1 orthographic depth (regularity in grapheme-phoneme correspondences) modulated Korean-English and Farsi-English bilinguals’ (n = 25 each) production of fricatives in English words (e.g.,  /ˈmeloʊ/ vs.  /ˈmelən/). Native English speakers (n = 25) served as a control group. Because fricatives are produced as geminate sounds in both Korean and Farsi, we expected L1-based transfer. Participants completed four tasks: an eye-movement reading task, word-naming task, cloze test, and language background questionnaire. The stimuli were controlled for word frequency, word length, number of syllables, and stress. We expect language-specific differences, corroborating previous neuro-linguistic evidence that shallow and deep orthographies differentially rely more heavily on phonological and lexical pathways, depending on language-specific demands. To explore this aspect, we employed an acoustic classification method for fricatives extracting cepstral coefficients and using HMMs to divide the sounds in regions based on their internal variance, aimed at determining whether fricatives produced by different groups can be classified correctly. This work has implications for both second-language (L2) speech learning models and classroom instruction.
Exploring the connection between articulatory skill and phonetic and phonological learning: A magnetic resonance imaging study
Authors: Spinu Laura , Shereen Duke , Myslyk Anastasiia , Rojas Mariany
Published: November 2022

Research has revealed positive consequences of bilingualism on cognition, some of which have been collectively referred to as the ‘bilingual advantage’, although the term remains controversial. The lack of replicability of such studies is often ascribed to methodological issues, such as the difficulty of quantifying the bilingual experience. Emerging areas of research where a consistent bilingual advantage has been identified include studies on phonetic and phonological learning (PPL)—the ability to learn the features of a novel accent effectively after initial exposure. Our main goal is to explore articulatory skill as a potential mechanism underlying the differences in PPL between mono- and bilingual populations. We used MRI instrumentation to visualize the movements of the tongue, lips and velum as our English monolingual and English-Spanish bilingual participants (n = 24) were trained to produce unfamiliar speech sounds, specifically high front rounded vowels, low back nasalized vowels, and secondarily palatalized labiodental fricatives. We also administered a PPL task and a performance-based test of language proficiency. With data analysis underway, we hypothesize that PPL correlates with articulatory skill and proficiency modulates the results across the board. Our study thus adds to the body of work on the coupling between sensory and cognitive functions.
Decoding the neural dynamics of within- and between-language lexical competition: A pediatric neurosurgical case report of a Spanish-English bilingual
Authors: Sarrett McCall E. , Rhone Ariane E. , Shea Christine , Hendrickson Kristi , Muegge John B. , Kovach Christopher , Dlouhy Brian J. , McMurray Bob
Published: November 2022

Spoken word recognition proceeds by immediately activating items in the mental lexicon which match the incoming speech signal. These items compete for recognition over time. In multilinguals, the array of possible lexical competitors includes items across all their languages. Eye-tracking work indicates that the strength of early competitor activation relates to listeners’ proficiency: words from the dominant language outcompete those from the other(s). However, the neural mechanisms that give rise to this effect are not well known. We present a case study of a pediatric neurosurgical patient who was bilingual in English (nondominant) and Spanish (dominant). The participant passively listened to English and Spanish cohort competitors. We used machine learning techniques to decode within- and between-language lexical competition dynamics from the pattern of activity on the superior temporal plane. Spanish words were more robustly decodable than English words, regardless of their role as a target word (the actual word heard on a given trial) or as a competitor (the phonologically related word competing for activation). This is consistent with a Spanish-dominant system—corroborating evidence from eye-tracking—and suggests that activation of cohorts may be in part due to perceptual tuning of early auditory areas for the sounds of a language.
The role of sensorimotor mechanisms in phonetic and phonological learning
Authors: Nieves Nicole , Spinu Laura , Myslyk Anastasiia , Duncan Llewellyn , Oreste Christie , Roodnauth Kevin
Published: November 2022

Phonetic and phonological learning was reported to be enhanced in bilinguals; however, the underlying mechanisms remain understudied. Prior work suggests a bilingual advantage in articulatory skill and auditory sensory memory, raising the question of the involvement of sensorimotor functions in phonetic and phonological learning. To explore this relationship, we compare the performance of English monolinguals and English-Spanish bilinguals on three tasks:(1) Articulatory skill, using a novel sound learning task with articulatory complex sounds not present in our participants' inventory.(2) Auditory sensory memory, measured via an adaptive digit span task. (3) Phonetic and phonological learning, using an artificial accent of English displaying diphthongization of mid-front lax vowels and tapping of intervocalic liquids. All tasks were conducted online 1-on-1 via Zoom. Tasks 1 and 3 were scored based on four listeners' perceptual judgments. For Task 2, we obtained response accuracy and input-output similarity scores. While data analysis is currently underway, preliminary findings replicate the previously observed bilingual advantage in phonological learning and auditory sensory memory and reveal a correlation between them. Bringing together motor, sensory, and acquisitional components and investigating the ways in which they are related adds to lesser explored mechanisms potentially underlying the bilingual advantage.
Geo-acoustic inversion using ground waves of explosive sounds
Authors: Wan Lin , Badiey Mohsen
Published: November 2022

The ground waves of explosive sounds exhibit strong dispersion in shallow water waveguides. Their travel time and amplitude are related to the geo-acoustic properties in the seabed and could be utilized to construct cost functions for geo-acoustic inversion. Following the analysis of the Airy phase [Wan et al., JASA, 143, EL199-205, (2018)], this research focuses on the extraction and utilization of ground waves, which propagate at frequencies below the corresponding Airy frequency. First, the ground waves of low order modes are identified in the received signals from explosive SUS charges deployed at various depths/ranges and recorded by vertical line arrays during the series of Seabed Characterization Experiments (SBCEX) conducted in the New England continental shelf and slope region. Then, the extracted ground waves, showing strong dispersive characteristics in a bandwidth of a few Hertz (i.e., between cut-off frequency and Airy frequency), are fed to a proposed inversion algorithm to obtain the estimated geo-acoustic parameters. Finally, the advantage of using ground waves rather than water waves is discussed and a physical explanation is provided. [Work supported by ONR Ocean Acoustics.]
Developing a virtual reality application for cultural heritage and room acoustics education
Authors: Park Sang Bum
Published: November 2022

We tend to use visual factors, such as architectural styles, features, specific decorations, historical contexts, etc., to characterize cultural heritage. Sound is a transient, ethereal phenomenon that tends to be neglected in historical records. While photographs and drawings can preserve the visual aspect of a building or scene, documenting the sonic impact of the spaces is more complicated. In particular, the historic places used for sonic activities, such as music halls, performance halls, and worship spaces, are essential to document and preserve the acoustic qualities. An immersive experience using virtual reality (VR) technology effectively promotes public awareness about cultural heritage's importance. It simulates the room acoustics using spatial audio technology. It also can make the VR environment interactive to manipulate architectural features that change the room acoustics, such as room volume, finish materials, reverberation time, sound barrier, etc. The main goal of this paper is to develop a VR application that can be used as a template to create a VR environment where 3rd to 8th-grade students navigate and learn about the history and architectural features of cultural heritage and the basics of room acoustics using a Quest headset.
Understanding production variability in multimodal communication
Authors: Lee Yoonjeong
Published: November 2022

A comprehensive view of speech communication requires a consideration of dynamic characteristics in language users’ multimodal behaviors. This talk discusses dynamic properties of both verbal and non-verbal communication behaviors, focusing on variability in voice, speech, and co-speech gesture production. I present a series of experiments that leverage quantitative approaches to examine how the multimodal production units of the cognitive system vary in their dynamic control and realization in executing communication goals. The overarching hypothesis is that surface variations in multimodal behaviors are structured to reflect communicative intentions, exhibiting a tight relation between the linguistic system and recruited modalities. Supporting evidence emerges from two types of data: dynamic voice signals drawn from speech corpora of various speakers, speaking styles, and languages, and time-aligned multidimensional signals of speech and co-speech gestures (simultaneously recorded audio, kinematic, and visual signals). Voice variations are acoustically structured by both biologically relevant factors and factors that vary with language-specific phonology. Furthermore, the spatiotemporal patterning of vocal tract actions and cooccurring body movements systematically varies, reflecting the prosodic structure of language. The findings and the utility of the analytical tools employed in these studies have implications for comparative investigations of communicative behaviors in animals. [Work supported by the NSF.]
Advances in aero-acoustics of flying beetles
Authors: Allen John S. , O'Rourke Kevin
Published: November 2022

An understanding of the acoustics of invasive species of beetles is needed for potential detection and tracking methods in agricultural monitoring. However, the underlying mechanisms of sound generation are not well understood, especially with respect to the higher harmonic sounds. The Coconut Rhinoceros Beetle (Oryctes rhinoceros) and the Oriental Flower Beetle (Protaetia orientalis) have been studied during tethered flight with synchronized microphone array measurements and high speed video (1000–10,000 fps). The larger Coconut Rhinoceros Beetles have fundamental ∼50 Hz with distinctive torsional wing rotation compared to Oriental Flower Beetle (∼100 Hz). Computational fluid dynamics simulations were performed using the unsteady compressible flow solver (CAESIM, Adaptive Research, Inc.) using a highresolution (TVD) methodology. Models of the wing flapping motion were accomplished using mesh deformation techniques with the flapping following from rotation with prescribed bending and coupled rotation and translation from the wing’s hinge position. Fluid structure interactions with respect to the wing’s flexibility are investigated in terms of the wing bending and the leading edge vortex formation.
High resolution focused-ultrasound-induced thermoacoustic imaging
Authors: Shan Tianqi
Published: November 2022

We report a new imaging modality, focused-ultrasound-induced thermoacoustic imaging (FUTAI). FUTAI provides high imaging resolution and unique contrast of acoustic absorption and thermodynamic properties of tissue. When a short pulse of the focused ultrasound beam is applied to biological tissue, the tissue will absorb the energy of the incident ultrasound causing a rapid change in local temperature, which leads to thermoelastic expansion and generates acoustic waves. In this work, we investigated this focused-ultrasound-induced thermoacoustic effect through theoretical simulation and experimental validation. A novel imaging modality FUTAI is proposed and demonstrated for the first time. By scanning the focus of the incident ultrasound beam, a 2D or 3D image of tissue properties can be formed. FUTAI provides better resolution compared to traditional B-mode ultrasound imaging, and deeper imaging depth compared to photoacoustic imaging. Additionally, since FUTAI is sensitive to acoustic absorption, it has unique advantages in guiding therapies like high intensity focused ultrasound (HIFU) in which treatment efficiency is determined by the acoustic absorption property. In this work, we also proposed a new method to localize the focus of HIFU with high accuracy using FUTAI. The results indicate that FUTAI has great potential in applications such as noninvasive imaging and therapy guidance.
In vivo thermal ablation control using three-dimensional echo decorrelation imaging in swine liver
Authors: Ghahramani Z. Elmira , Grimm Peter D. , Quillin R. Cutler , Patel Sameer H. , Ahmad Syed A. , Shah Shimul A. , Schoenleb Nicholas S. , Connolly Ben , Saremi Bahar , Mast T. Douglas
Published: November 2022

In experiments modeling clinical thermal ablation of liver tumors, radiofrequency ablation (RFA) of swine liver was controlled using a three-dimensional (3D) ultrasound echo decorrelation imaging. Up to six ablations with target diameter 2 cm were done in each animal’s liver using a clinical RFA system (RITA/Angiodynamics, 50 W, 6–10 min). Paired sequential volumes of beamformed pulse-echo data (inter-frame time <50 ms) were acquired from a Siemens Acuson SC2000 scanner with a Z6Ms transesophageal matrix array and transferred via an Ethernet to a computer running a custom MATLAB program to compute 3D echo decorrelation images. When the average cumulative, motion-compensated echo decorrelation within the planned ablation zone exceeded a prespecified threshold determined from preliminary trials, ablation was ceased automatically. After each procedure, the animal’s liver was excised, uniformly sectioned, and optically scanned to reconstruct 3D ablation zones. Local ablation prediction was assessed using receiver operating characteristic (ROC) curve analysis comparing echo decorrelation images to co-registered ablation zones. To assess differences in outcomes, ablation zone volumes, ablation rates, Dice coefficients for measured versus targeted ablation zones, and ROC curves were statistically compared for controlled versus uncontrolled trials. The results indicate promise for control of in vivo thermal ablation using motion-corrected 3D echo decorrelation imaging.
Exploring the benefits of spatial and temporal block-wise filtering architectures
Authors: Weeks Abbie , Byram Brett
Published: November 2022

Spatial block-wise filtering architectures improve noise stationarity locally, making SVD-based filtering more robust (Song et al., 2017). Temporal block-wise filtering has been proposed to augment spatial block-wise methods for 3D Doppler data acquired via mechanical translation (Chen et al., 2021) and compensate for bulk motion in cardiac power Doppler imaging (Zhang et al., 2021). We combine spatial and temporal block-wise architectures to suppress noise through depth and better capture time-varying signals with power Doppler. We show that a combination of spatial and temporal block-wise methods provides improved CNR (3.9 dB gain), SNR (0.9 dB gain), and CR (11.7 dB gain) over spatial block-wise alone and propose two methods for selecting temporal block sizes. First, we select temporal ensembles from systole, early-, and late-diastole from matched ECG data. Second, we derive a temporal SVD cutoff between the blood and noise subspaces for the entire ensemble. We use that cutoff as a proxy for correlation length and select ensembles accordingly. We collected 2 s of liver data from a healthy volunteer (nine angled plane waves at 600 Hz PRF and 4.1667 MHz center frequency) and applied spatial and temporal block-wise SVD filtering with 100-sample ensembles and 50-sample temporal block sizes overlapped at 20%.
Assessment of flaws in cold sintered ZnO via longitudinal ultrasonic wave speed and attenuation measurements
Authors: Jones Haley N. , Trolier-McKinstry Susan , Arguelles Andrea P.
Published: November 2022

The cold sintering process (CSP) is a low temperature processing technique that utilizes a transient phase to synthesize dense ceramics. However, some CSP parts contain microflaws that arise due to pressure gradients and inhomogeneities in temperature and distribution of the transient phase. This work uses high frequency ultrasound (20 MHz) to verify the presence of defects larger than 15 μm in effective radius in CSP ZnO samples of varying densities (84–97%). The acoustic data were compared to X-ray Computed Tomography (XCT) images to validate the findings. Acoustic metrics used in this work include wave speed, which is affected by differences in the effective elastic properties of the medium, and attenuation, which is wave energy loss due to scattering from defects, including those smaller than the wavelength. Wave speed maps were inhomogeneous suggesting density gradients which were verified with SEM. Areas of high attenuation (> 300 Np/m) are present in all samples independent of relative density and correspond to defects identified in XCT ranging from 15 μm to 50 μm in effective radius. This suggests the presence of microflaws possibly due to the inhomogeneous removal of the transient phase. However, some high attenuation spots do not correspond to visible defects in XCT which suggests the presence of features such as texturing which are undetectable with XCT. These results show the viability of high frequency ultrasound for defect detection in cold sintered ZnO.
Numerical and experimental analysis of ultrasonic scattering in two-phase polycrystalline materials
Authors: Islam Showmic , Uchic Michael , Turner Joseph A.
Published: November 2022

Many polycrystalline materials found in nature and used in industry consist of multiple phases. Careful nondestructive characterization of these materials is of fundamental importance for quality assurance because microstructure is strongly correlated with mechanical performance. A fundamental understanding of ultrasonic scattering from idealized two-phase materials would provide essential information regarding the predictive nature of scattering measurements to quantify such microstructures. For this purpose, samples were created using spark plasma sintering (SPS) from mixtures with different ratios (with respect to mass) of copper and iron powders. These samples were used for measurements of wave velocity, attenuation, and backscatter. Prior ultrasonic scattering models for continuous media were modified for discrete synthetic two-phase three-dimensional microstructures. In this way, the ultrasonic scattering responses were determined numerically using DREAM. 3D based on 30 realizations of synthetic microstructures representative of each volume fraction. In this presentation, the computational approach is described, and the results are then compared with the microstructures and ultrasonic data from the samples made from the binary mixtures. The results show some agreement as well as highlight some limitations of the computational model. Finally, prospects for more complex materials are discussed. [Research supported by the Air Force Research Laboratory (AFRL) under prime contract FA8650-15-D-5231.]
Vowel trajectories of African Americans in Georgia, USA
Authors: Renwick Margaret E. , Forrest Jon , Glass Lelia , Stanley Joey
Published: November 2022

Within the United States, dialectal variation is often characterized by vowel shifts: systematic differences in vowels' relative qualities and vowel-inherent dynamics. The African American Vowel Shift (AAVS), in particular, includes raising and fronting of front lax /ɪ ɛ æ/, among other features. The more recent pan-regional Low Back Merger Shift (LBMS), by contrast, includes lowering and backing of the same vowels. We evaluate these two shifts in an audio corpus of over 40 Black speakers from the Southern state of Georgia. Speakers, born between the 1930s and 2000, represent five demographic generations. Normalized formant values (F1,F2) from five temporal points per token are input to Generalized Additive Mixed Models (GAMMs). We test for significant changes in vowels' trajectories across time by fitting Year of Birth as a continuous smooth term. Additionally, we use linear mixed-effects modeling to test for raising versus lowering on the (F2–F1) front-vowel diagonal, across generations. Evidence from GAMMs and linear modeling indicates raised positions of /ɪ ɛ æ/ among older generations (1950s–1980s), followed by significant retraction from 1990–2000. These acoustic results are consistent with strengthening of the AAVS in the third quarter of the 20th Century, followed by a rapid transition to the pan-regional LBMS.
The role of voice fundamental frequency in the perception of anger in clear speech
Authors: Ferguson Sarah H. , Bennion Sierra N. , Smalley Tara E. , Young Elizabeth D.
Published: November 2022

In previous work, listeners rated clearly spoken neutral speech materials as sounding angry significantly more often than identical materials spoken conversationally. This effect varies widely among talkers, and a recent study compared acoustic characteristics of clear and conversational speech produced by talkers whose clear speech sounds angry to those of talkers whose clear speech does not sound angry. Of several well-known clear speech acoustic changes, only raised voice fundamental frequency (fo) differed for talkers who do and do not sound angry when speaking clearly. To test whether raised fo causes clear speech to sound angry, the present study used six talkers whose clear speech was rated as sounding angry and who also made sizeable fo shifts when speaking clearly. For each talker, nine pairs of identical sentences (one from each speaking style) were identified. Praat was then used to lower the pitch of the clear sentence to match the pitch of the conversational sentence and to raise the pitch of the conversational sentence to match the pitch of the clear sentence. Listeners with normal hearing will hear these sentences and rate the emotion they heard in each item from a set of six emotions.
Vowel duration before voiced and voiceless stops in the Indian English of Assamese speakers
Authors: Wiltshire Caroline , Sarmah Priyankoo
Published: November 2022

Speakers of many English varieties produce longer vowels before voiced obstruent codas than before voiceless (e.g., House and Fairbanks, 1953; Chen, 1970; Umeda, 1975; Van Santen, 1992), though the extent can vary (Jacewicz et al., 2007; Tanner et al., 2019; Deterding, 2005). While phonetic motivations have been proposed to explain this pattern (Ohala, 1983; Kluender et al., 1988), the effect in some varieties of English is observed to be larger than phonetically motivated (Ohala, 1983; Keating, 1985); furthermore, some languages have less of a voicing effect (e.g., Korean, Russian, and French in Chen, 1970) and others may have none at all (e.g., Polish and Czech in Keating, 1985). This study investigates the phenomenon in the second largest variety of English by population, Indian English. Twenty Indian English speakers, all with L1 Assamese, were recorded reading a word list including 40 monosyllables that place vowels before voiced and voiceless versions of the same stop. We measure vowel duration using a Praat script to determine whether and to what extent this variety shares in the lengthening pattern, and in addition to providing the first measures of the phenomenon in Indian English, our results will be compared with other varieties of English and other languages.
Competing prosodic influences on VOT length in Hawaiian
Authors: Davidson Lisa , Parker Jones 'Ōiwi
Published: November 2022

Previous research on voice onset time shows that VOT in unaspirated stops is at best only weakly affected by prosodic strengthening (Hodgson, 2021; Simonet et al., 2014). VOT duration is analyzed in Hawaiian, which has only /p k/, in conjunction with a prosodic analysis, to determine its stop type, and investigate whether prosodic boundaries condition VOT length. Data comprise speech from seven speakers interviewed on the radio program Ka Leo Hawai‘i in the 1970–80s (Kettig, 2021). Using the computational prosodic grammar in Parker Jones (2010), stops were coded for whether they occurred in lexical word-initial/medial position, in a stressed/unstressed syllable, and in prosodic word-initial/medial position. The results indicate that the average duration of /p/ is 24ms and /k/ is 41ms, the latter being on the higher end of unaspirated stop ranges (Cho and Ladefoged, 1999). VOT is significantly longer before stressed word-medial syllables, but shorter before stressed word-initial syllables. For word-medial stressed syllables, VOT is also significantly longer when the syllable is in prosodic-word initial position. VOT length may have separate functions in Hawaiian unaspirated stops: strengthen a lexical word boundary especially before an unstressed syllable via shortening, but lengthen word-medially to demarcate a prosodic word boundary.
Voice quality as an indicator of speaker's social information and as a cue for sound change
Authors: Gao Xin , Wen Rui
Published: November 2022

Voice quality reflects a variety of information in speech. The present study examines how voice quality may indicate a speaker's social information. We examine the ongoing /yø∼y/ merger in Shanghainese Wu. The first vowel formant (F1) and Harmonics-to-noise ratio (HNR) are extracted from 80 speakers. We also collect social information including age, gender, and immigrant background, family language, and working language. Mixed-effects linear regression models are built with the F1/HNR difference between /yø∼y/ as the dependent variable. Significant age effects are found on both F1 (β = 0.043, p = 0.006) and HNR (β = −0.055, p = 0.024); F1 is also more merged for female speakers than males (β = −0.521, p = 0.001); HNR is more distinct for speakers from non-immigrant families than speakers from immigrant families (β = 1.858, p = 0.008). The study shows a tendency for /yø∼y/ to merge in terms of both vowel quality and voice quality. It is noteworthy that speakers of native origin participate in the vowel-quality merging (cued by F1) but not in the voice-quality merging (cued by HNR). Taken together, voice quality can function as an independent indicator of a speaker’s social attributes.