bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on Spark Assisted and Hot Surface Assisted Compression Ignition (SACI, HSACI) in a Naturally Aspirated Single-Cylinder Gas Engine
Authors: Judith Joern Alexander , Kettner Maurice , Schwarz Danny , Klaissle Markus , Koch Thomas
Published: April 2023

Spark assisted compression ignition (SACI) represents an efficacious technique to extend the operating range and control combustion timing in homogeneous charge compression ignition (HCCI) engines. Recently, a hot surface ignition system (HSI) was demonstrated to enable hot surface assisted compression ignition (HSACI) featuring similar combustion characteristics compared to SACI. This work compares both combustion processes with regard to control and combustion characteristics, the strength of the ignition systems, and cycle-by-cycle variations (CCV). Engine trials were conducted using a single-cylinder research engine fueled with natural gas. The engine operated naturally aspirated at an engine speed of 1400 1/min and steady-state conditions. Experimental conditions cover relative air-fuel ratios λ = 2.1–3.1, intake temperatures Tin = 140–170 °C and intake pressures pin = 993–995 mbar. Results show similar capabilities of SACI and HSACI to control combustion timing by means of spark timing in SACI and hot surface temperature in HSACI. Heat release analyses of individual combustion cycles point out the similarity of both combustion processes. The evaluation of the strength of the ignition systems reveals that HSACI extends the lean limit by Δλ = 0.05–0.10 and advances the earliest applicable combustion timing (MinCA50) by ΔMinCA50 = 1.0–4.5 °CA provided that ringing is not of concern. Comparison of CCV in HCCI, SACI, and HSACI shows highest combustion stability for HCCI, followed by SACI. HSACI evinces highest CCV due to a larger variation at the start of combustion.
Numerical Modeling and Analysis of Energy-Assisted Compression Ignition of Varying Cetane Number Jet Fuels for High-Altitude Operation
Authors: Sapra Harsh Darshan , Hessel Randy , Amezcua Eri , Stafford Jacob , Miganakallu Niranjan , Rothamer David , Kim Kenneth , Kweon Chol-Bum M. , Kokjohn Sage
Published: April 2023

Computational fluid dynamics (CFD) simulations are performed to study the potential of energy-assisted compression ignition (EACI) strategy for enabling ignition and enhancing combustion of different cetane number jet fuels during high-altitude operation. EACI employs an ignition assistant (IA), which is an advanced glow-plug design with the ability to sustain higher temperatures for prolonged periods, to provide the necessary ignition energy for precise ignition control and enhanced combustion. In the numerical simulations, the combustion chemistry solver is coupled with a multicomponent wide distillation fuel mechanism, energy source modeling, and a turbulence-chemistry interaction model to accurately capture the ignition assisted-combustion. The simulation is first validated against optical engine measurements for cetane number (CN) 48 jet fuel and then transferred to another single-cylinder test engine to study the ignition and combustion characteristics of EACI with CN 35 jet fuel at varying IA temperatures. Simulation results show that EACI significantly improves fuel ignitability. Ignition delay reductions for CN 48 fuel of 57% and CN 35 fuel of 25% are noted at IA temperatures of 1550 K and 1405 K compared to when the IA is switched off. Furthermore, EACI improved the combustion efficiency to 99.7% compared to the 90% estimated for the IA off case in the optical engine.
Impact of Ignition Assistant on Combustion of Cetane 30 and 35 Jet-Fuel Blends in a Compression-Ignition Engine at Moderate Load and Speed
Authors: Miganakallu Niranjan , Stafford Jacob , Amezcua Eri , Kim Kenneth S. , Kweon Chol-Bum M. , Rothamer David A.
Published: April 2023

This study investigates the use of a commercial-off-the-shelf (COTS) ceramic glow-plug to assist ignition of jet fuel blends with cetane numbers of 30 and 35, below the minimum cetane number of 40 for #2 diesel. Experiments were carried out on a single-cylinder compression-ignition engine operating at 1200 RPM for single and dual-injection (pilot + main) timing sweeps. The COTS glow-plug, termed the ignition assistant, was operated at varying input power levels between 0 and 70 W (stock maximum power input is 30 W) at each SOI. Results demonstrate that the use of an ignition assistant at the higher input powers (50 and 70 W) enables operation over a wider range of SOI timings where more advanced times are limited by high pressure-rise rates and more retarded times are limited by rapidly increasing coefficient of variation of gross indicated mean effective pressure. Use of the ignition assistant enables stable combustion at later injection timings increasing the operable range of SOI timings. For the CN 30 fuel, at earlier injection timings, pressure traces, and heat release analysis demonstrated the advancement of start of combustion and combustion phasing with the ignition assistant on. At retarded injection timings where combustion would not otherwise occur completely for the CN 30 fuel, operating the ignition assistant at the higher powers enabled combustion phasing to be advanced and combustion to be stabilized at conditions where, with the ignition assistant off, misfire (flameout) would occur. Furthermore, the ignition assistant enabled combustion phasing to follow an approximately linear response with respect to SOI timing over a wider range of SOI times.
Dynamic ultrasound localization microscopy
Authors: Provost Jean
Published: April 2023

Ultrasound localization microscopy (ULM) can map the vasculature at large depth with unprecedented resolution by localizing millions of injected microbubbles in hundreds of thousands of images acquired over a few minutes. The current state of the art in ULM is to use low concentrations to achieve the best possible spatial resolution without providing temporal information, which limits the development of functional biomarkers such as pulsality or the imaging of moving organs like the heart. In this work, we will present dynamic ultrasound localization microscopy (DULM), which enables the generation of dynamic images of the vasculature of periodic phenomena by using a combination of enhanced image formation and processing techniques to drastically increase the number of microbubbles that can be detected in each image. Specifically, we will describe how the detection of microbubbles directly in space time along with novel aberration correction algorithms and a motion-invariant Lagrangian beamforming approach can be used to increase the concentration of microbubbles 5-fold with a limited degradation in resolution. Examples of application for the mapping of pulsatility in the brain and the dynamics of the intramyocardial blood flow in 2D + t and 3D + t will be shown.
Low-delay interactive rendering of virtual acoustic environments with extensions for distributed low-delay transmission of audio and bio-physical sensor data
Authors: Grimm Giso , Kothe Angelika , Hohmann Volker
Published: April 2023

In this study, we present a system that enables low-delay rendering of interactive virtual acoustics. The tool operates in the time domain based on a physical sound propagation model with basic room acoustic modelling and a block-wise update and interpolation of the environment geometry. During the pandemic, the tool was extended by low-delay network-transmission of audio and sensor data, e.g., from motion sensors or bio-physical sensors such as EEG. With this extension, distributed rendering of turn-taking conversations as well as ensemble music performances with individual head-tracked binaural rendering and interactive movement of directional sources is possible. Interactive communication requires a low time delay in sound transmission, which is particularly critical for musical communication, where the upper limit of tolerable delay is between 30 and 50 ms, depending on the genre. Our system can achieve latencies between 7 (dedicated local network) and 100 ms (intercontinental connection), with typical values of 25–40 ms. This is far below the delay achieved by typical video-conferencing tools and is sufficient for fluent speech communicationand music applications. In addition to a technical description of the system, we show here example measurement data of head motion behaviour in a distributed triadic conversation.
End behavior of the acoustic standing wave in a flue organ pipe
Authors: Kellison Makayle S. , Moore Thomas R. , Coyle Whitney L. , Cannaday Ashley E.
Published: April 2023

The acoustic standing wave in a transparent flue organ pipe has been imaged using high-speed transmission electronic speckle pattern interferometry. Spectral filtering of the interferograms at the acoustic resonance frequency of the gas inside the pipe results in an image showing the sinusoidal pressure dependence inside the pipe as well as the expected extension of the standing wave beyond the pipe end. However, the image also reveals anomalous and unexplained behavior as the standing wave transitions from inside to outside the pipe.
A study of impedance of brass instruments and mouthpieces—Comparison of models and measurements
Authors: Jackson Miranda
Published: April 2023

The impedance of a brass instrument has an important influence on the frequencies of the notes that can be played and on the timbre of the sound. The shape of the mouthpiece has various features, such as the cup volume and shape, opening diameter, and length, that determine the characteristics of the overall impedance of the instrument-mouthpiece combination. Brass instruments, and especially mouthpieces, are designed for specific purposes, and many brass players own several different horns or mouthpieces, and choose which to use depending on their particular musical requirements at the time. In order to investigate the relationship between the physical parameters of instruments and mouthpieces and the resulting impedance, brass instruments and mouthpieces have been modeled with transfer matrix techniques, and the results are compared with impedance measurements of the instruments alone, the mouthpieces alone, and combination of instruments and mouthpieces. Trumpets, flugelhorns, horns, trombones, and the corresponding mouthpieces have been used for this study. The mouthpiece-instrument combination has been investigated in terms of intonation, playability, and timbre. The question of whether (and why) some mouthpieces are more suited to certain instruments and certain playing styles is investigated as well as the effect of varying the physical parameters of mouthpieces and instruments.
Frequency characterization of laser microphones
Authors: Cunningham Carson F. , Hopps Alexandra M. , Losee Wyatt , Sandberg Richard , Allred David , Neilsen Tracianne
Published: April 2023

Historically, lasers have been used for a variety of purposes such as spectroscopy or optics. Lasers have even been used as a surveillance device; however, minimal research has been done in this area. In this experiment, a laser microphone was designed and tested with several different colored lasers to determine the frequency response of the received signal due to wavelength differences from the emitted light. The laser microphone included two telescoping lenses and an interferometer setup with a flimsy mirror as one of the arms. This mirror created a vibrating diffraction pattern when sound waves were played in close proximity. The interferometer was set up in an anechoic chamber, and a transimpedance photodiode was used to collect data of a moving diffraction pattern. With this setup, different sounds were recorded with varying levels of clarity, and the spectral response of the laser microphone was analyzed. With further research, a choice of laser color could be chosen to optimize the signal’s response.
Individual variability in speech recognition with compression and beamforming at positive signal-to-noise ratios
Authors: Rallapalli Varsha H. , Freyman Richard , Souza Pamela E.
Published: April 2023

Individuals with hearing loss often struggle to communicate in noisy conditions. Aggressive hearing aid (HA) processing, such as fast-acting wide dynamic range compression (WDRC), may reduce speech recognition under some circumstances, and there is concern about disproportionate reductions in listeners with poor working memory. We investigated how speech recognition is affected when WDRC is combined with highly directional beamforming intended to reduce noise from lateral and rear locations. We also sought to determine how listener factors—working memory, age, and hearing loss—affect such interactions in typical listening conditions, including positive signal-to-noise ratios (SNR) and different spatial noise locations. To-date 22 listeners with mild to moderately severe sensorineural hearing loss repeated low-context sentences (0°) mixed with six-talker interference at + 3 and + 8 dB SNRs, distributed equally in two ( + /−90°) or three ( + /−90°/180°) locations. Wearable HAs presented four signal processing combinations, matched for audibility: microphone directionality (omnidirectional or beamformer) and WDRC (fast- or slow-acting). Data show higher speech recognition with beamforming (re omnidirectional), especially at + 3 dB SNR, regardless of WDRC and spatial locations. Relative contributions of listener factors will be assessed in mixed models in the context of combined signal distortions from HA processing and interferers. [Work supported by NIH-K01DC018324.]
The effects of background noise and reverberation on speech perception in cochlear implant users
Authors: Mollison Abbie A. , Peng Z. Ellen
Published: April 2023

Indoor noise and reverberation interfere with speech understanding for listeners. Degradation in cochlear implant (CI) processing presents additional challenges for CI users to understand noisy and reverberant speech. Inthis study, we investigated the effect of adverse acoustics on speech perception on three tasks that changed in difficulty and increasing need for top-down processing: (1) word recall, (2) sentence recognition, and (3) conversation comprehension. Each task was tested in five conditions that varied in combinations of adverse acoustics from reverberation (i.e., anechoic, 0.4s RT, vs 1.2s RT) and noise (i.e., quiet versus Speech-shaped-noise at −3dB). We compared performances from normal-hearing (NH) listeners and bilateral CI users between 15 and 25 years old. Preliminary results show that while NH listeners may have some tolerance for speech perception under adverse acoustics, CI users experienced more graded performance deterioration with increasing reverberation and noise. Moreover, we observed task-dependent performance change across adverse acoustic conditions in both NH and CI listeners: While some context (i.e., sentences) may help speech perception, comprehension based on pragmatic language processing (i.e., conversations) is vulnerable under difficult listening situations. These results provide insights on how NH and CI listeners differ in their access to top-down processing in real-world speech perception.
A functional test for hearing aids outcomes assessment
Authors: Garudadri Harinath , Hunt Martin , Daita Aadyanjali , Yellamsetty Anusha , Rallapalli Varsha H.
Published: April 2023

We present a functional test for speech understanding called hearing aids (HAs) objective outcomes – HO2 (pronounced as /hɑ:t/) app. It uses natural speech stimuli and generates word level accuracies, phonetic, and broad-phonetic confusion matrices. In the current best practices, hearing loss (HL) is diagnosed using pure tone audiometry (PTA). While PTA is also a functional test, it characterizes only sound detection ability of discrete pure tones, but not overall speech intelligibility due to cochlear impairments leading to sensorineural hearing loss. HO2 app stimuli are based on minimal contrast sets (MCS) of words in a given language. Each word within a subgroup of MCS words differ in a minimal set of (acoustic) phonetic features resulting in a different meaning—phonemics of the given language. The tool includes configuration parameters to include video and closed captions to minimize the role of higher level (cortical) language processes. Researchers can save HO2 app experimental conditions in a configuration file and share with others for repeatability and reproducibility. We present the feasibility of normal and hearing-impaired subjects (mild and moderate HL) to self-administer speech comprehension tests in multiple listening conditions using HO2 app. For the hearing-impaired subjects, results in unaided and aided conditions are presented.
Preliminary findings from a study relating the effects of hearing loss and listening conditions on postural sway to fall risk in older adults
Authors: Francis Alexander L. , Rietdyk Shirley , Haddad Jeffrey , Newell Melissa , Christ Sharon , Burgin Sarah
Published: April 2023

Hearing loss is associated with increased fall risk in older adults, but multiple mechanisms have been proposed to account for this. Hearing loss may reduce spatial awareness and/or increase cognitive load, both of which may increase fall risk but may be ameliorated by hearing aid use. Here, we present preliminary results from an in-progress study comparing fall incidence in daily life with postural sway measured under various listening conditions in older adults with and without hearing aids. Seventeen adults aged 65 to 81 years (7 using bilateral hearing aids, 10 without) stood with feet together and eyes closed, listening to noise vocoded speech (4, 8, 16 channels) and spatially distributed environmental sounds (silence, 1, 3 sources) for 1min per condition while postural sway was recorded in the lab. Participants subsequently reported daily near-falls and falls for 4 months. Results suggest hearing aid users show less postural sway, potentially indicating greater rigidity which has been associated with greater fall risk. However, near-fall incidence was lower for hearing aid users. Further analyses showed higher near-fall rates associated with higher auditory thresholds, but hearing aid use may mitigate this trend. We are currently collecting more data with a wider variety of participants.
The impact of hearing aid user's own voice on device signal processing
Authors: Budinsky Robert A. , Ozmeral Erol J. , Eddins David A.
Published: April 2023

Hearing aid processing is designed to improve audibility for sounds of interest, often by targeting external speech signals. During natural conversation, however, the hearing aid user is also the source of speech, potentially interacting with hearing aid function and leading to suboptimal processing. In this study, we investigated how the presence of own voice impacts the deployment of specific features designed to enhance audibility and intelligibility of conversational partners. We recorded real-time hearing aid feature engagement (directional microphones, noise reduction, and speech enhancement) during simulated conversations in quiet and in background noise. Simulations were performed using an acoustic manakin (GRAS 45BC-12) capable of producing speech via internal speaker, which was situated in the center of a 24-speaker spatial array. The results demonstrate how the presence of a hearing aid user’s own voice disrupts the intended use of these adaptive features, and that there is a need for optimizing hearing enhancement devices to account for own voice in dynamic scenarios. Future studies will determine the impact of a hearing aid user’s own voice on the device’s ability to improve speech intelligibility and user satisfaction.
Estimation of bottom attenuation in shallow water with changing depth using intensity fluctuations due to moving nonlinear internal waves
Authors: Katsnelson Boris , Grigorev Valery , Jiang Yanyu
Published: April 2023

The use of analysis of intensity fluctuations in the presence of non-linear internal waves (NIWs) for estimating the bottom attenuation is demonstrated in (JASA, v.140, p.3980, 2016) using data of Shallow Water 2006. Key objects of this analysis are the time dependence and spectrum of the total intensity (summed over the entire depth of the waveguide, in other words, over all hydrophones of the vertical line array—VLA). In this paper, we consider data on the measurement of field fluctuations (frequency 224 Hz) on an acoustic track ∼ 30 km long in the presence of NVWs, obtained in the ASIAEX 2001 experiment. The acoustic track consists of two parts: “deep,” (∼ 270 m) and “shallow” (∼ 120 m). This feature leads, first, to variation of NIW parameters, propagating toward the coast, and second, it gives reason to assume different bottom properties for these sub-tracks. The paper proposes a technique for estimating the attenuation coefficients independently for two parts based on the study of spectrograms at the VLA and spectrum of total intensity, and the following fitting between experimental data and theoretical modeling. The obtained attenuation coefficients are compared with the data of other authors for the same area.
Estimating seabed properties with a residual convolutional network
Authors: Neilsen Tracianne B. , Mortenson Michael C. , Schemel Amanda , Knobles David P. , Hodgkiss William
Published: April 2023

Deep learning can assist in characterizing seabeds using sources of opportunity such as shipping noise. While previous work focused on seabed classification, this study uses a residual convolutional neural network to find individual seabed properties. The training data were labeled with sound speed, density, attenuation, and thickness of the layer values of the top sediment layer. A comparison was made between predictive capabilities of ResNet-18 networks when trained to learn a single parameter and those trained to simultaneously learn multiple parameters. For stiff parameters—those with high information content in the data—learning an individual parameter performed better. These single parameter predictions are fundamentally different from a geoacoustic inversion for one parameter. In geoacoustic inversion, all other parameters are held at a fixed value. In deep learning, variability in all other parameters is contained in the training data, but the network focuses on features in the data related to a single property. The trained networks are applied to ship noise measured during the 2017 Seabed Characterization Experiment. [Work supported by the Office of Naval Research and the National Science Foundation’s REU program.]
Round and round we go: Speech intelligibility and localization for in-the-round spaces
Authors: Magloire Eric , Cardenas Bruno , Harrison Byron
Published: April 2023

The directional characteristics of the human voice are a key theatrical effect in spoken word drama. Maintaining intelligibility and believable localization as performers move and reorient on the stage is a formidable design challenge for in-the-round spaces. We provide an overview of the design strategies for this theatrical form using some notable precedents. Referencing Chicago’s newest in-the-round theatre at Steppenwolf Theatre, we present the acoustic goals and the architecturally integrated design for speech acoustics. The presentation includes the key design parameters and the traditional and non-traditional intelligibility metrics used to evaluate the design options and the completed construction, along with subjective impressions of artists and audiences related to speech intelligibility and localization.
The Acentech acoustical checkout: Measuring and listening to completed performance spaces
Authors: Rogers Kelsey , Sacks Jonah , Zaman Khaleela
Published: April 2023

Visiting a completed performance space is an invaluable learning opportunity. Our practice at Acentech has evolved to include approximately equal parts measurement and listening. We report relevant findings to the owner and design team; but often, much of the information that we collect is for our own internal research and development. This presentation will summarize our process for evaluating a completed performance space, including measurement, visualization, and analysis of spatial impulse responses, listening to and recording speech and music in the room, and listening to calibrated convolutions of measured spatial impulse responses with anechoic audio. Ideas for future analysis tools and related research efforts will also be discussed.
Blue whales track oceanographic variability across spatial and temporal scales
Authors: Oestreich William , Benoit-Bird Kelly , Ryan John P.
Published: April 2023

Animals' ability to track variable resources in space and time is critical to their survival in dynamic and changing ecosystems. Understanding populations' behavioral flexibility in response to natural and anthropogenic ecosystem variation requires long-term and detailed measurements of both animal behavior and ecosystem properties. In a series of recent studies, we leverage blue whales' widely-propagating songs to understand their capacity to track ecosystem variability across episodic foraging and seasonal-to-interannual migration scales. By integrating individual and population-level study of singing blue whales, we first identify an acoustic signature of their population-level transition from foraging to migration. Applying this acoustic signature to a six-year study period, we find that blue whales flexibly time their transition to migration to track interannual variability in the phenology of their foraging habitat. Within the foraging season, we further track blue whale behavior via a directional acoustic vector sensor. Using this approach, we find that blue whales maximize access to aggregated prey patches by dynamically tracking fine-scale wind-driven upwelling plumes in space and time. Combined, these findings display blue whales' ability to track oceanographic variability across spatial and temporal scales and suggest mechanisms by which these predators individually and collectively sense their dynamic foraging habitat.
Comparing distributed acoustic sensing data with hydrophone recordings
Authors: Abadi Shima , Douglass Alexander S. , Ragland John
Published: April 2023

Distributed acoustic sensing (DAS) is a technology that transforms telecommunication fiber optic cables into dense sensor arrays by continuously transmitting pulses of light down the cable and measuring backscattering from natural inhomogeneities within the fiber cable. The technology can densely sample the acoustic field over long ranges (up to 100 km), providing a means for large scale passive acoustic monitoring. To evaluate the capabilities of DAS, it is necessary to benchmark and calibrate the technology relative to traditional hydrophone data. The DAS Calibration Experiment 2022 (DASCAL22) recorded 9 days of both DAS and hydrophone data in Puget Sound, WA in October 2022. The DAS data were recorded with a sample rate of 2 kHz, and the cable extended 3.5 km on the seafloor between two islands, reaching depths of 100 m, and the hydrophones were moored adjacent to the DAS cable at 5 m and 25 m from the seafloor. The recordings include impulses from an active source at 1 m, 5 m, and 10 m depths, and an abundance of passive acoustic data corresponding to ship traffic, wind, and rain. This work aims to draw comparisons between the hydrophone and DAS recordings to evaluate the capability of DAS at detecting sounds at frequencies as high as 1 kHz.
Microring resonator based disposable ultrasound-sensing chronic cranial window
Authors: Sun Cheng
Published: April 2023

Chronic cranial window (CCW) has been widely used to provide optical access to the brain cortex for longitudinal imaging, while preserving the physiological environments of the brain. Various optical imaging modalities have been demonstrated with CCW for longitudinal brain imaging, including single-photon and multi-photon fluorescence microscopy, optical coherence tomography, and photoacoustic microscopy (PAM). However, sophisticated surgeries and windows designs are still required for chronic imaging and direct cellular recording or manipulation because the surgical implantation of CCW precludes direct physical access to the brain other than optical access. Here, we report an active CCW with integrated ultrasound sensor based on a transparent microring resonator (MRR). The MRR is fabricated on a quartz substrate by using low-cost soft nanoimprinting lithography (sNIL) and then integrated on a glass window with optical fibers for disposable ultrasound-sensing CCW (usCCW). Encapsulating MRR inside an acoustic impedance matched protection layer further improves its reliability for in vivo applications over the observed period of a month. The functions of the active usCCW are experimentally validated through longitudinal (PAM) imaging of cortical vasculature in live mice over a 28-days period.
Acoustic plane wave detection of intracranial cavitation in a polyacrylamide human head model under blunt impact
Authors: Galindo Eric J. , Tartis Michaelann
Published: April 2023

Traumatic brain injuries (TBIs) occur in everyday life in the form of blunt impacts, while military personnel experience a combination of blast and blunt impacts from explosives. Damage mechanisms in TBIs, including cavitation, are poorly understood due to the inability to optically monitor brain deformation inside the skull during collisions. To overcome these limitations, high frame rate acoustic plane wave imaging in conjunction with high-speed optical imaging were combined to visualize intracranial cavitation during impact of a transparent brain phantom. The full-scale phantom was composed of 7% and 10% (w/v) polyacrylamide (PAA) andenclosed in a 3D printed skull with acrylic windows for optical image acquisition. This surrogate utilizes simplified geometry to represent key anatomical features such as the gyri, sulci, and ventricles while possessing rheological properties similar to the human brain. Optical and acoustic data correlate cavitation to high-contrast regions. Acoustic spectra show expected harmonic and broadband behavior during cavitation bubble growth and collapse. Further processing with superresolution techniques may enhance cavitation localization providing a stand-alone acoustic tool applicable in various TBI scenarios allowing observations at depth, where optical techniques are limited.
Ultrasound cycloplasty for refractory glaucoma treatment: The EyeTechCare Experience
Authors: Wolf Dietrich , Lafond Maxime , Lafon Cyril
Published: April 2023

In the 1980s, HIFU was successfully tested for treating refractory glaucoma (Lizzi et al.). A more recent device from EyeTechCare, made of six cylindrical transducers operating at 21MHz, can perform a conformal, partial, and fast thermal ablation of the ciliary bodies, a technique known as ultrasound cycloplasty (UCP). For the last 10 years, we investigated the safety and efficacy of UCP for reducing the production of aqueous humor and intraocular pressure (IOP). The primary outcomes that were validated (more than 55%) were therapeutic success (IOP reduction from baseline ≥20% and IOP >5 mm Hg without other surgical procedures) and vision-threatening complications. Secondary outcomes included mean IOP change from baseline at each follow-up visit, medication use, complications, and subsequent UCP and/or other postsurgical interventions. This technique was associated with a low complication rate and no cases of phthisis. In this presentation, we also highlight the remaining challenges in increasing the efficacy and reliability of UCP and its future developments. [Disclosure: Dietrich Wolf is CEO at EyeTechCare.]
Ultrasonic cavitation processing of multi-functional materials
Authors: Tzanakis Iakovos , Priyadarshi Abhinav , Prentice Paul , Mi Jiawei , Pericleous Koulis , Eskin Dmitry
Published: April 2023

Ultrasonic cavitation processing (USP) is a versatile technique that has gained a lot of momentum in the last decade as a sustainable, environmentally friendly, and cost-effective process. USP uses high-frequency sound to form bubbles that expand, contract, and eventually collapse, generating high-speed liquid jets, powerful shockwaves, and acoustic streaming effects. Despite its widespread application, use of USP remains mostly empirical. For processes involving the synthesis and production of materials, harnessing the power of cavitation requires an understanding of the fundamental mechanisms driving USP. In this presentation, we record recent studies to analyse, optimise, and control USP for applications related to grain refinement of aluminium alloys, exfoliation of 2D nanomaterials, and processing of composites. High-speed cameras and in situ synchrotron imaging were used to visualise cavitation dynamics, coupled with state-of-the-art hydrophones to detect acoustic waves and shockwave emissions. Results show that optimised USP with the help of advanced modelling significantly improves grain refinement of aluminium alloys in processes such as direct-chill (DC) casting, where shockwaves are primarily responsible for the fragmentation of intermetallic crystals/dendrites. Furthermore, shockwaves act as the main driving mechanism for the exfoliation of 2Ds while cavitation activity enhances fibre dispersion in highly viscous polymers, improving matrix stability and strength.
Acoustic resonators for detecting low frequency events
Authors: Schmalenberg Paul , Singh Parveen , Severgnini Frederico , Dede Ercan
Published: April 2023

Acoustic resonators and related concepts have long been the subject of research for acoustic filtering in free space or energy harvesting applications. In this work, we instead apply acoustic resonators to low frequency (< 50 Hz) non-contact bio-signal sensing within a vehicle cabin. We describe our approach to the design of the resonator and method of simulation in this low frequency regime. Validation of select designs through experiments in both free space and using a coupled bodies method is discussed. We also demonstrate the bio-signal collection in situ and discuss challenges associated with a real-world, noisy, dynamic environment. Future work including signal processing of noisy data to recover the base bio-signal and ideas for miniaturization of the device are touched upon.
Tonal center of gravity predicts variation in the interpretation of rising and falling intonation in American English
Authors: Sostarics Thomas , Cole Jennifer
Published: April 2023

In English, the pitch trajectory at the end of a phrase distinguishes assertions from questions, through falling versus rising intonation, respectively. This study asks if, within these broad classes, variation in the shape or slope of the pitch excursion is meaningful. Recent work proposes a phonological distinction between two tonally distinct sub-categories of rising intonation: shallow rises favor an assertive interpretation, while steep rises favor a question interpretation (Jeong 2018). We test an alternative analysis, where the probabilistic association between intonation and assertive/inquisitive interpretation arises not from a discrete difference between shallow and steep rises, but from meaningful variation within the rising class. We present findings from two perception experiments where listeners hear short utterances and identify the speaker’s intention to ASK or TELL. Pitch resynthesis (PSOLA) was used to create a stimulus continuum of phrase-final rising and falling F0 trajectories that vary in the slope and shape of monotonic F0 trajectories. Our results show a probabilistic relationship between interpretation (ASK/TELL) and rise variation, but do not support the previously proposed phonological distinction between shallow and steep rises. We propose a more parsimonious model of within-category variation grounded in the Tonal Center of Gravity acoustic measure (Barnes et al. 2012).
Children’s perception of gender in other children’s voices
Authors: Holt Christopher E. , Baumgartner Quinn , Jacewicz Ewa , Fox Robert A.
Published: April 2023

Studies investigating perception of speaker gender in children have mostly been conducted with adults as listeners in experimental tasks. Based on these adult judgments, results converge in showing that the gender of prepubescent children can be identified well above chance (even in the absence of reliable anatomical differences related to their vocal tract morphology) and that sentences provide more gender cues than do isolated syllables. Our previous work added that adults can utilize sociocultural cues in regional dialects in making their gender identification decisions (Holt etal., 2022). Here, we examine how children perceive gender in other children’s voices, and whether their judgments differ appreciably from adults. Children ages 8-11 years listened to various utterances (isolated syllables, read sentences, and spontaneous speech) of age-matched peers from three dialect regions in the US. Our provisional findings are that, overall, children are less sensitive to gender cues than the adults, and their judgments are more dependent on the talker’s age than on information in longer passages of speech in sentences and talks. Contrary to adults, regional dialect does not seem to influence children’s decisions, suggesting that perceptual attunement to a particular variety may not facilitate gender identification in other children.
Listener descrimination between age differences in two speakers
Authors: Ozdogan Lara , Tucker Benjamin V.
Published: April 2023

Often when listeners hear a speaker they have an impression of the age of the speaker. The present research seeks to determine how well listeners are able to identify a speaker’s age when provided with two different recordings from one speaker. Previous research has asked participants to place a speaker’s age on a continuum or estimate the age of the speaker. In the present study, we use an AX task which asks listeners to determine whether the X recording is younger or older, from speech recorded from two speakers spanning approximately 20 years. We also asked a few questions with regard to the listeners’ language background, age, and experience with populations over the age of 40. We analyze the descrimination responses of our listeners, and find that listeners are not much better than chance in determining age differences in the recordings. We do find that as the number of years between recordings increases, participants are more accurate at determining the age difference between recordings. Listeners have fairly specific ideas about what acoustic features they are using to perform their descrimination, however these do not necessarily lead to more accurate descrimination.
Production and perception of novel consonant clusters
Authors: Kelley Matthew C. , Oganyan Marina , Wright Richard A.
Published: April 2023

The present study details a visual world paradigm eye tracking experiment on perception and production of novel consonant clusters. The clusters varied in difficulty based on sonority or perceptual salience scales. During the familiarization phase, listeners heard and watched a story on-screen and produced the names of novel creatures and objects. Each story focused on one cluster. Four creatures/objects were introduced corresponding to the (1) target cluster (e.g., [dlɑpɹ]), (2) epenthesized cluster competitor (e.g., [dəlɑkn]), (3) first cluster consonant (e.g., donkey), and (4) second cluster consonant (e.g., lollipop). During each trial, participants verbally identified one of the four creatures/objects, and their gaze was tracked. We analyzed the productions and gazes to investigate the relative difficulty of producing and perceiving the consonant clusters. We predicted participants would (1) correctly produce/perceive a cluster, (2) epenthesize a vowel/perceive vowel epenethesis, or (3) perceive/produce only one of the cluster sounds. We statistically analyzed the participants’ propensity toward each behavior in both production and perception. As part of the analysis, we examined whether participant behavior was better predicted by analyzing the clusters with the sonority sequencing principle or in terms of acoustic salience and cue recoverability.
Perception of talker height in children’s productions of sustained /ɑ/
Authors: Thomas Abbey L. , Barreda Santiago , Assmann Peter F.
Published: April 2023

Children’s voices reflect changes in physical size as they grow. At a previous ASA meeting, we showed that adult listeners can estimate the height of child talkers, ages 5–18 years, from /hVd/ syllables. The present study focuses on listener judgments of child talker height from a sustained /ɑ/ vowel, which lacks durational cues and transitions between phonological segments. The stimuli for this experiment were 1-s excerpts with stable amplitude and fundamental frequency (F0) from sustained /ɑ/ tokens by 174 talkers (including those from the /hVd/ experiment). 18 adult listeners judged talker sex and height for each token. Judgments of each talker’s height were consistent across the two experiments. Perceived talker height was moderately correlated with actual height (r = .66). When talker sex was identified incorrectly, height was underestimated for taller females and overestimated for males. Consistent with our previous study, significant relationships were observed between listener judgments of talker height and acoustic measures (geometric mean of the lowest three formants, F0, and additional variables related to the voicing source). The results extend findings from the previous study, showing that the relationship between summary acoustic measures and perception of talker height is preserved when the stimuli comprise only sustained /ɑ/.
Effects of weak shear rigidity of the seabed on sound propagation in a range-dependent ocean
Authors: Godin Oleg A.
Published: April 2023

The shear wave speed is often small compared to the compressional wave speed in unconsolidated marine sediments. Sediment stratification and especially mass density variation in the seabed enhance the effects of weak shear on acoustic normal modes in range-independent ocean and produce significant shear wave contributions to mode attenuation in shallow water [O. A. Godin, J. Acoust. Soc. Am., 149, 3586–3598 (2021)]. A distinctive feature of the shear-induced perturbations in the mode phase speed and attenuation is their rapid variation with sound frequency due to shear wave interference within a sediment layer. This paper investigates theoretically the shear wave-induced perturbations in normal mode phase, travel time, and attenuation when water depth and/or sediment layer thickness vary gradually with range. Frequency dependencies of the adiabatic normal mode travel time and attenuation are found to be highly sensitive to range dependence of the seabed layering. Gradual changes in the sediment layer thickness have an effect similar to frequency averaging or artificially increased shear wave attenuation. Implications of these findings for geoacoustic inversions will be discussed. Contributions of shear rigidity and cross-range gradients of the sediment layer thickness to horizontal refraction of normal modes will be also examined. [Work supported by ONR.]
In-Progress Updates to ANSI S12.60 Part 1 Pertaining to Building Sound Isolation
Authors: Keefe Joseph
Published: April 2023

In early 2022, work began to update ANSI/ASA S12.60, Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools—Part 1 Permanent Schools. The current version of this standard is from 2010. When the working group was polled for comments and requested changes for a new version of the standard, concerns regarding how the 2010 version handles building envelope sound isolation requirements were numerous. The current progress of the working group’s actions regarding modifications to the standard’s building envelope sound isolation language will be discussed.
Quantifying teachers’ response to acoustic environments: a review of several recent studies
Authors: Hunter Eric J.
Published: April 2023

School teachers have an elevated risk of voice problems due to the vocal demands in the workplace. This presentation summarizes the results of several studies investigating voice use in real and simulated classroom settings. The first study used 57 teachers, who were monitored all day for 2 weeks in teaching and nonteaching environments. In the second study of short-term responses to room conditions, the speech of 20 talkers was analyzed in order to evaluate how voice production and effort were affected by speaking style, room acoustics (added background noise, presence of early reflections), and short-term vocal fatigue in a single room. A third study investigated the effects of voice production and perception due to visually concealed acoustic changes (both noise and reverberation) while speaking in a room. In all studies, talkers significantly adjusted their voice production to both dramatic and seemingly small acoustic changes. Both teaching experience and biological sex were factors in participant response differences.
Adaptive behavior in sonar prey tracking tasks: Empirical data and modeling
Authors: Wilkinson Michael G. T. , Wang XingYao , Cowan Noah J. , Moss Cynthia F.
Published: April 2023

Echolocating bats can discriminate small differences in target range (Simmons, 1973) and show a clutter interference zone along the range axis of 8–9 cm (Simmons et al., 1988). Because bats use an active sensing system, they can employ various strategies to mitigate the effects of clutter. We studied clutter rejection behaviors of the big brown bat, Eptesicus fuscus, as it tracked a moving target under controlled conditions. We also created data-driven models using control theory and system identification techniques to evaluate oscillating target motion tracking strategies. We trained bats to rest on a stationary platform and track a moving tethered mealworm in two conditions (1) approaching and passing by stationary clutter objects at varying distances and angular offsets, and (2) moving in sinusoidal patterns in an open room. Data from the first experimental condition revealed adaptive echolocation call features and head movements that enabled target tracking in the presence of clutter. Under the oscillating target condition, we analyzed adaptive echolocation behavior to create a data-driven model that maps changes in target motion with sonar call rate. The results of this study demonstrate the bat’s use of active motor control that separates targets from clutter and to track complex motion trajectories.
Studying dolphin biosonar with the jittered-echo paradigm
Authors: Finneran James , Mulsow Jason , Houser Dorian
Published: April 2023

In his 1979 paper “Perception of echo phase information in bat sonar” [Science 204, 1336–1338], Jim Simmons introduced the “jittered-echo” paradigm. In this method, bats discriminated between electronic echoes with fixed delay (i.e., simulating fixed range) and those with delays that alternated (“jittered”) on successive echoes. The jittered-echo paradigm was developed to minimize the interfering effects of head movement, under the assumption that head movement between successive pulse emissions is negligible. Echo delay thresholds obtained with the jitter technique are small, with multiple studies reporting sub-microsecond echo delay thresholds in the big brown bat. The jitter method has also been controversial, because of the extremely low echo delay resolution (10 ns) and sensitivity to echo phase (fine structure) reported by Simmons. Recently, the jitter delay paradigm has been adapted for underwater use with dolphins. Results with dolphins show qualitative similarities to those from bats: echo delay thresholds below 1 μs and sensitivity to echo fine structure. This talk will briefly review Simmons’ and other’s biosonar jitter experiments with bats, then present in detail experiments with bottlenose dolphins featuring jittered echo delay and phase.