bluuebunny/crossref_metadata_2025 huggingface dataset:
Using MEG to assess the neural mechanisms of phonetic distributional learning and future language growth in 2- and 6-month-old infants
Authors: Bosseler Alexis , Clarke Maggie , Tavabi Kambiz , Kuhl Patricia K.
Published: November 2021

Infants are sensitive to the distributional characteristics of the speech they hear, and perception can be altered by the distributional properties of language input. Infants listening to languages with distinct distributional properties show altered perception at the age of 6 months based on learning from ambient language input. Perception can also be altered in the laboratory by manipulating the distributional characteristics of speech in a 2-min exposure. However, the brain mechanisms underlying this learning are not well understood. Here we used MEG to explore the neural processes involved in on-line distributional learning. We examined brain responses to ambiguous speech sounds that straddle a /ba-wa/ speech continuum. Infants were tested longitudinally at 2 and 6 months of age not only to assess whether effects of experience can be documented between 2 and 6 months, but also to determine whether individual differences in brain response can predict future language growth. Our results show that differences in the magnitude of the brain response to ambiguous speech sounds in brain regions involved in auditory speech processing, motor planning, and attention change from 2- to 6-months-of- age. Moreover, we found that individual differences in these regions predict language growth up to 27 months of age.
Speech perception and the sensorimotor system in Infancy
Authors: Choi Dawoon , Werker Janet F.
Published: November 2021

The speech that infants perceive and learn from is highly multisensory. Preverbal infants show multisensory speech sensitivities prior to direct associative experience, for instance, even to non-native speech that they have not experienced before. Sensorimotor influences on auditory perception are of increasing interest in the context of speech perception development. In a series of experiments, we explored whether infants’ speech perception is influenced by articulatory-auditory relations. Specifically, we experimentally restricted the movement of infants’ relevant articulators during speech perception tasks. We review a series of studies showing both behavioral (eye-tracking) and neural (EEG) evidence that preverbal infants’ auditory speech perception is influenced by articulatorily specific sensorimotor input at 6- and 3- months of age. To control for the possibility of learning, we tested both native and non-native (hence not visually nor auditorily familiar) phonetic contrasts. To explore whether the auditory-sensorimotor relation is in place even without feedback from self-produced vocalization, we tested consonant discrimination in infants as young as 3-month, who are not yet babbling and are unable to produce consonant sounds. Our results show that the sensorimotor-auditory link is in place prior to specific experience watching, hearing, or producing the relevant sounds.
MIPA: A theory of phonological acquisition and speech motor control
Authors: Masapollo Matthew , Nittrouer Susan
Published: November 2021

Despite long-standing interest in the relation of early speech production and phonological development, little is known about how speech motor skills develop in tandem with emerging phonological representations in childhood. Recent experimental work in our laboratory has shown that better speech motor control at young ages is associated with better outcomes at later ages in phonological sensitivity. In this talk we will advance a new, theoretical model to account for these findings. It is termed MIPA (Motor Involvement in Phonological Acquisition) and proposes that highly developed sensorimotor maps for speech support the acquisition of detailed phonological representations. We will begin by providing an overview of the model, its core predictions, and compare it to existing frameworks. We will then describe experimental studies designed to explore the conceptual merits of the model by testing children longitudinally on a set of measures assessing the coordination of vocal-tract gestures, phonological sensitivity, and the relationship between those two skills. Application of the model to the study and treatment of children with developmental disabilities that affect speech production, such as stuttering, as well as language-related disorders arising from poor sensitivity to phonological structure, such as dyslexia, will also be briefly described.
A neurocomputational view of developmental stuttering
Authors: Guenther Frank
Published: November 2021

An estimated 5% of children go through a period of stuttering around 3–5 years of age, with stuttering persisting into adulthood in approximately 20% of these children. Research into the neural underpinnings of stuttering have identified a number of structural and functional anomalies in various components of the left hemisphere cortico-basal ganglia-thalamocortical motor loop in children and adults who stutter. This talk will present the theoretical view that this loop is heavily involved in the initiation of speech motor programs (rather than encoding sensory-motor transformations that make up the motor programs themselves) and that stuttering is primarily a disorder of speech initiation rather than one of impaired motor programs for speech. Relevant neural and behavioral findings will be reviewed in light of this hypothesis, including findings that seemingly implicate audio-motor transformation difficulties in stuttering. In the current view, these latter findings are interpreted as evidence of difficulty in using auditory information to determine the appropriate time to initiate the next motor program in a speech sequence.
Speech processing in the age of machine learning: not all models and solutions are created equal
Authors: Hansen John H.
Published: November 2021

The speech processing field has evolved dramatically in the last decade, especially for non-specialists using speech technology tools. Machine learning based on various neural networks (DNNs, GANs, CNNs, LSTMs, etc.), have emerged as a way of leveraging available training data to formulate new algorithms which have revolutionized performance for many challenging tasks including speech recognition, speaker identification, speech enhancement, etc. However, with such improved modeling capabilities, greater care is needed to ensure resulting solutions take into account fundamental properties of speech production, language, and perception. This talk provides a brief overview of current speech processing advancements using model based/supervised solutions. In particular, after briefly highlighting several approaches to speech processing, three examples are considered that highlight challenges/flaws/issues in applying supervised model-based concepts and machine learning without factoring in underlying foundations present in the original data context. These areas include: (i) word-count estimation for language assessment of child-adult speech—comparing with LENA language system, (ii) dialect identification using available corpora (e.g., “is the secret in the silence?”), and (iii) speech features for forensic audio analysis with noise and nonlinear distortion mismatch conditions. Suggestions for best practices will be highlighted in speech, speaker, and language based processing.
Precursor arrivals of explosive sounds during the Seabed Characterization Experiment 2021
Authors: Wan Lin , Badiey Mohsen , Knobles David P.
Published: November 2021

Travel time and amplitude of precursor arrivals of explosive sounds in shallow water contain information of marine sediments and could be used for geoacoustic inversion. The precursor arrivals have been identified in the received signals from explosive SUS charges detonated during the Seabed Characterization Experiment (SBCEX2021) conducted in the New England continental shelf and slope region in the summer of 2021. These SUS charges were deployed at various ranges along and across 200-m and 250-m bathymetry contours and recorded by two vertical line arrays (VLAs) positioned at 200-m and 250-m water depths. In addition to the two acoustic VLAs equipped with environmental sensors, there were three environmental moorings simultaneously capturing the water column fluctuation of temperature and salinity. In this research, measured precursor arrivals are first extracted and analyzed. Simulated results are then obtained and compared with the measured ones. Finally, a sensitivity study of the precursor arrivals on water column sound speed and sediment parameters (e.g., sound speed and attenuation) is performed. [Work supported by ONR Ocean Acoustics.]
Estimation of seabed attenuation in the New England Mud Patch
Authors: Potty Gopu R. , Miller James H. , Bonnel Julien , Lin Ying-Tsong , Godin Oleg A.
Published: November 2021

Measurements of acoustic pressure and particle velocity were made during the Seabed Characterization Experiment (SBCEX-2017) in the New England Mud Patch south of Cape Cod in about 70 m of water. This experimental location is characterized by a “soft” layer of surficial sediment consisting of mud. University of Rhode Island and Woods Hole Oceanographic Institution deployed the “geosled” with a four-element geophone array, a tetrahedral array of four hydrophones, and several hydrophone receive units (SHRUs) as data acquisition packages. In addition, a new low frequency source, interface Wave Sediment Profiler (iWaSP) was deployed to excite interface waves (Scholte waves). The geophone array was localized using the known locations of the acoustic sources and noise from the research vessel. Modal arrivals from broadband sources on geophones and hydrophones were used to invert for compressional and shear wave speeds and attenuation in the mud layer and the underlying sand layer. Effect of shear conversion effects on the modal attenuation estimates and it’s frequency dependence will be explored. The role of shear conversion along the mud-sand interface will be discussed. [Work supported by the Office of Naval research, code 322 OA.]
Underwater implosion of re-enforced concrete piers
Authors: Donavan Paul , Rymer Bruce
Published: November 2021

From 2015 through 2018, 18 reinforced concrete piers formally supporting the east span of the San Francisco-Oakland Bay Bridge were removed using underwater demolition. The events ranged from one pier to up three piers at one time with the number of charges ranging from 92 to 688 and weights from 12 to 35 pounds. In all cases, a bubble curtain, blast attenuation system was used to reduce the blast pressures. Although the blast plans varied, more variation in the monitored peak sound pressure levels and sound exposure levels was observed than was expected from initial predictions. Potential causes of this variability were examined including varying charge confinement, directionality due to self-shielding of the structures as the individual blasts progressed, the effect of varying distance to the monitoring location for the individual charges, obscuration of the monitoring location due to intervening structures, and varying effectiveness of the blast attenuation system. Each of these potential causes are examined in this presentation.
Construction of the Maxxon acoustical laboratory
Authors: Way Evelyn , Lilly Jerry G.
Published: November 2021

This presentation will discuss the construction of the Maxxon acoustical laboratory from the initial excavation to final completion, highlighting the problems and solutions that were met along the way. Special attention will be paid to the non-standard construction used for the lab including the acoustic isolation joint, managing services across the isolation joint, specialty equipment, doors, and paint. The selection and implementation of the test system of microphones and sound sources will also be discussed.
Visual acoustical performance analysis and storytelling
Authors: Miller-Klein Erik
Published: November 2021

With photo-enabled sound intensity systems acoustical practitioners can investigate and understand the root cause of acoustical performance previously unavailable to our industry. This seminar will show examples of measured performances that show the opportunities, limitations, and opportunities for acoustical assessment with this unique technology. See case studies on rapid prototyping, performance validation, and challenges to common “rule of thumb" approaches.
Early-stage acoustic optimization of absorptive concrete panels in buildings
Authors: Self Ian , Broyles Jonathan , Butko Daniel , Brown Nathan C.
Published: November 2021

Although architectural acoustic design solutions have existed for many centuries, modern advances in material science and construction technology have allowed new possibilities in terms of cost, environmental impact, or systems integration. One design approach with significant architectural potential is to use porous concrete panels to reduce the reverberation and loudness within a space, particularly for larger classrooms, lecture halls, and multipurpose rooms. While porous concrete panels have been previously shown to improve acoustic environments, modifications to mix designs and form geometry can have substantial effects on acoustic criteria such as sound absorption. This presentation begins with a low-resolution acoustic simulation procedure for analyzing concrete panels that is coupled with validating and comparing to previous experimental data. The process then uses multi-objective optimization to shape the concrete panels at the early design stage for the best acoustic performance with the least material, using a parametric model of curved, sawtooth concrete geometry. The low-resolution model validation utilizes raytracing and image sourcing analyses to obtain the Reverberation Time, from which approximate absorption coefficients and corresponding NRC ratings of the concrete panels can be calculated and compared to experimentally derived data from physical concrete panels. Optimal panel shapes are then recommended for improved acoustic performance.
A comparison of transient killer whale (Orcinus orca) whistles in Alaska
Authors: Newman Kelly A.
Published: November 2021

Several species of dolphins in both isolated and continuous regions exhibit geographic variation in whistles. Although whistles are thought to be learned, possible structural components are exhibited across communities. Whistles from three transient killer whale (Orcinus Orca) groups, Prince William Sound, the Pribilof Islands, and False Pass were compared for spectral and temporal properties. Of 395 randomly selected frequency contours of whistles, there were 32 shape categories of whistles. Overall, whistle shapes from different areas reflect homogeneity, with four whistle shapes comprising 50% of all repertoires. The most common whistle contour shapes were up, down, flat, and oscillatory. Whistles from at St. Paul Island, described here for the first time, had higher fundamental frequencies and shorter durations than whistles from Prince William Sound and False Pass. Surface whistles from St. Paul Island had higher mean frequencies than those recorded at depth with passive acoustics. One identical whistle type was found at both St. Paul Island and False Pass, which suggests the same whales travel between the two areas. The longest whistles and most variable whistles were recorded at False Pass.
Quantification of deep sound scattering layers using a moored upward-looking broadband split-beam echosounder
Authors: Zhuang Zhaozhong , Lavery Andone C.
Published: November 2021

Distinct deep sound scattering layers are prevalent throughout the ocean mesopelagic zones (200–1000 m depths). These deep sound scattering layers are often characterized by daily vertical migration, in which many of the inhabitants of the ocean mesopelagic communities migrate to shallow waters during the night to feed, and descend during the day to avoid predators. And yet little is known about the impact of mesoscale physical oceanography, such as warm core rings or Gulf stream meanders, on the patterns of daily vertical migration or on the small-scale spatial distribution, or patchiness, of the deep sound scattering layers. To address these questions, an upward-looking broadband split-beam echosounder (36 kHz–44 kHz) has been moored at 580 m depth in the slope waters south of the New England shelf break in a location in which warm core rings are a prevalent feature. Data from a 3-day test deployment are analyzed in terms of target density, spectral characterization, patchiness and timing of the migrations. The calibrated broadband spectra of individual targets are used to determine the number of swimbladdered fish in the deep sound scattering layers. Meanwhile, two other methods, including echo-counting and echo-statistics, are also applied to give target density estimation.
Determination of nonlinearity parameter B/A of liquids by comparison with solutions of the three-dimensional Westervelt equation
Authors: Chien Lonnie , Cormack John M. , Everbach E. Carr , Hamilton Mark F.
Published: November 2021

Though nonlinear propagation depends upon the nonlinearity parameter B/A of the medium, it is often difficult to measure accurately. Thermodynamic methods often require high temperature and pressure excursions that can damage fragile molecules. Finite-amplitude methods often require unrealistic assumptions of ideal piston sources to account for diffraction effects. An alternative, described here, is to use the numerical solution of the three-dimensional Westervelt equation for weakly nonlinear fields (considering up to 10 s of harmonics of the fundamental frequency), and to match measured harmonic generation with that for simulated media. In particular, we follow Jafarzadeh et al. [Ultrasound Med. Biol. 47(3), 809–819 (2021)] to find that the nonlinearity parameter of a liquid can be recovered by determining the best match between measurements and simulations of media with different B/A values. Ideal piston sources with radial symmetry are not required, only a high-spatial-resolution hydrophone scan of the near-field source plane. Other techniques to determine the nonlinearity parameter by comparing propagation models with experiments, such as Richard et al. [New J. Phys. 22, 063021 (2020)], may improve on earlier measurement methods.
Non-linearities under highly focused high-intensity ultrasound fields
Authors: Dash Pradosh Pritam , Arvanitis Costas
Published: November 2021

High-intensity focused ultrasound (HIFU) has seen widespread clinical adoption as a therapeutic tool, as it may be targeted noninvasively and without ionizing radiation. The converging sound waves induce thermal (e.g., ablation) and mechanical (e.g., radiation force) effects that may be localized to manipulate or destroy tissue. In addition to these primary effects, finite-amplitude acoustic influences (e.g., second harmonic generation) become relevant due to the high-pressure levels near the focal region. One of the ways these nonlinear effects occur is when a pressure wave develops at the difference frequency due to the nonlinearity of the medium when an acoustic beam is driven by a signal that contains two high but slightly different frequencies. This is termed as “scattering of sound by sound,” an implication of finite-amplitude propagation is the existence of sum and difference frequencies. Using highly focused ultrasound beams as carrier waves at high amplitudes, we have observed that these nonlinear effects can be localized at scales below its wavelength with sufficient amplitudes. These effects were observed for a water reference medium, and thus are likely to be even more prominent in tissue. Exploring these higher-order acoustic effects for the diagnosis and treatment of human diseases is warranted.
Recondensation of nano-sized perfluorocarbon droplets after acoustic droplet vaporization for blinking ultrasound localization microscopy
Authors: Burgess Mark , Aliabouzar Mitra , Aguilar Christian , Fabiilli Mario L. , Ketterling Jeffrey
Published: November 2021

Ultrasound localization microscopy (ULM) is a promising super-resolutionimaging technique based on the build-up of subwavelength localizations of gas-filled ultrasound contrast agents (UCAs) within the microvascular space. Slow flow regions can reduce localization rates and diminish the isolation of microbubble signals from tissue. This work compares the blinking contrast dynamics of nano-sized perfluorocarbon droplets to the slowly changing contrast dynamics of traditional gas-filled UCAs. A 16-MHz linear array connected to a Verasonics research ultrasound system was used to capture high-frame rate acquisitions of contrast agents flowing through an in vitro- flow phantom. Nano-sized droplets produced an on and off contrast signal due to vaporization/recondensation events which enhanced microbubble separation from tissue. This allows for higher localization rates for droplets at slow flow speeds, since a new population of bubbles was localized with each ultrasound pulse and was independent of flow speed. This could improve ULM at slow flow speeds, where UCAs require long acquisition times for adequate microbubble movement via flow to produce sufficient localization rates. Preliminary in-vivo experiments comparing UCAs to nano-sized droplets for contrast-enhanced imaging of a mouse kidney will also be discussed. [This work was supported by NIH grant R21 HD097485.]
Impact of phase-change contrast agent size during activation using ultrasound
Authors: James Dominique , Merillat Darrah , Sirsi Shashank , Hoyt Kenneth
Published: November 2021

Phase-change contrast agents (PCCAs) are liquid nanodroplets (ND) that transition into gas microbubbles (MB) when exposed to pulsed ultrasound (US) . The purpose of this study was to investigate the activation threshold of size-isolated PCCAs under physiologically relevant hydrostatic pressures. Size-isolated PFB NDs were prepared using an extrusion method and filter sizes of 100 or 400 nm. Using a programmable US scanner and linear array transducer, a custom scan sequence was implemented that interleaved pulsed US transmissions for both PCCA activation and MB detection. An automated US pressure sweep was performed (3 to 6 MPa, N = 200 discrete intervals), and grayscale US images were acquired at each increment. PCCAs were circulated through a flow phantom at 37 deg. Hydrostatic pressures applied to the PCCAs was controlled by constriction of flow phantom tubing. Reference measures were recorded by a calibrated pressure catheter. Activation thresholds were quantified using custom MATLAB software. The US-detected PCCA activation threshold increased with increased hydrostatic pressure in the range of 0 to 75 mmHg. The 100 nm size-isolated PCCAs activated at a higher US pressure as compared to 400 nm agents (4.3 ± 0.2 mmHg versus 3.7 ± 0.2 mmHg, p < 0.001). A positive correlation was found between the PCCA activation threshold and applied hydrostatic pressure for both 100 and 400 nm PCCAs (R 2 > 0.95, p < 0.001). This strong linear relationship could be exploited for noninvasive pressure estimation using US and PCCAs.
C-mode passive cavitation images for predicting large volume FUS-mediated drug delivery outcome
Authors: Gong Yan , Chien Chih-Yen , Ye Dezhuang , Chen Hong
Published: November 2021

Passive cavitation detection has been commonly used to monitor focused ultrasound (FUS)-mediated blood-brain barrier disruption (FUS-BBBD). Previous research by our team has shown the feasibility to correlate passive cavitation imaging (PCI) with drug delivery outcome via FUS-BBBD at a single target. This study proposed to perform c-mode PCI for predicting the spatial distribution of aPD-L1 delivered by FUSBBBD. A single-element FUS transducer was used to perform sonication iteratively in a 3×3 grid at the whole brainstem of wild-type mice. PCI were acquired using an ultrasound imaging probe co-aligned with the FUS transducer. Reconstruction was performed to obtain c-mode PCI for the whole sonicated area in the plane normal to the PCI imaging plane (axial plane of FUS transducer). Fluorescence-labeled aPD-L1 was intravenously injected after FUS sonication and the delivery outcome was quantified using ex vivo fluorescence imaging. A high correlation (R2 = 0.79) was obtained between the fluorescence intensity and the cavitation dosage calculated from the c-mode PCI. No significant difference was found between 3dB area of the fluroescence images (6.93 ± 2.24mm2) and the 3 dB area of the c-mode PCI images (7.20 ± 0.74mm2). This study demonstrated that the c-mode PCI had the potential to predict drug delivery outcome by large volume FUS-BBBD.
Affordable stereotactic-guided focused ultrasound device for tunable drug delivery to the mouse brain
Authors: Hu Zhongtao , Chen Si , Yang Yaoheng , Gong Yan , Chen Hong
Published: November 2021

Focused ultrasound combined with microbubble (FUS+MB)-mediated blood brain barrier (BBB) opening is not only a promising technique for clinical applications but also a powerful tool for preclinical neuroscience and neuro-oncology research. However, existing FUS systems are expensive and lack the flexibility of modulating BBB opening volume, which prevents a broader research community from adopting the FUS+MB technique in preclinical studies. To address the challenge, we developed a low cost (∼$100), mini FUS transducer with the capability to modulate BBB opening size that can be readily integrated with a standard stereotaxic frame for mouse. Specifically, we manufactured in-house mini FUS transducers with three frequencies (1.5, 3.0, and 6.0 MHz), and quantified BBB opening and targeting accuracy at varying pressures (0.20 to 0.81 MPa). The volume of FUS+MB-induced BBB opening was evaluated using both contrast-enhanced MRI and Evans blue extravasation. Our results showed that we can achieve varying amount of Evans blue delivery and BBB opening size by modulating the transducer frequency and acoustic pressure. Additionally, the amount of Evans blue delivery and BBB opening had a significant linear correlation with the cavitation index (defined by the ratio between acoustic pressure and frequency). We believe that this stereotaxic-guided FUS system will lower the barrier for adopting the FUS technique in a broader research community.
A modified acoustic-turbulent scattering model for long-range propagation with wind tunnel validation
Authors: Zhang Tianshu , Miller Steven A.
Published: November 2021

We present a newly developed ‘bridging’ model to quantify turbulent effects on long-range acoustic propagation in the atmosphere. The bridging model is incorporated into an existing validated Burgers’ equation solver. The new model combines the scattering model of Ostashev and Wilson and a traditional refraction model for acoustic-turbulent interaction. A new attenuation coefficient is obtained that is consistent with the atmospheric attenuation coefficient via integration of energy loss over all scattering angles. To validate and quantify the effect of the new model, we conduct a series of propagation experiments in the National Science Foundation funded University of Florida Boundary Layer Wind Tunnel. A synthetic noise signal propagates through the tunnel, which has controllable boundary layer turbulent statistics via fan speeds and hundreds of individually controlled roughness elements. We compare predictions of the bridging model, Ostashev and Wilson’s model, and the experiments of the wind tunnel. Also, we perform example long-range predictions using the new model and Ostashev and Wilson’s model with a synthetic tornadic infrasound signal. A sensitivity test of model parameters is performed. We show that for particular atmospheric conditions and turbulent statistics, the bridging model has particular advantages with minimal additional computational expense.
High-fidelity fan-noise simulations based on improved delayed detached eddy simulation
Authors: Suzuki Takao , Shur Michael L. , Strelets Michael K. , Travin Andrey K. , Spalart Philippe R.
Published: November 2021

We have developed high-fidelity CFD/CAA capability for the prediction of fan tone and broadband noise from an aero-engine. With a zonal URANS—wall-modeled LES approach, referred to as the Improved Delayed Detached Eddy Simulation (IDDES), the entire geometry of NASA's Source Diagnostic Test (SDT) fan rig including the nacelle is solved at approach, cut-back and take-off conditions. Multi-block grids with high-order structured finite-volume schemes are designed to resolve turbulence in the wakes and vortices as well as sound propagation in the bypass duct through the blade rows. By applying the Ffowcs-Williams and Hawkings technique with permeable surfaces, far-field sound-power spectra are computed, and by incorporating with the duct-mode-extraction technique, the radiated sound from the inlet and exhaust is decomposed into duct modes. These predicted fan-noise characteristics as well as aerodynamic performances are validated against NASA’s wind-tunnel test data. The fan-noise associated with the rotor-stator interaction is very well characterized: The tone power levels up to the second blade passing frequencies from both inlet and exhaust are predicted well across the engine speed, and the broadband power spectra are also predicted except for those from the inlet only at supersonic tip Mach numbers.
Acoustics of rotor ingesting an axisymmetric turbulent boundary layer
Authors: Wang Meng , Zhou Di , Wang Kan
Published: November 2021

The noise generation by a five-bladed rotor ingesting an axisymmetric turbulent boundary layer at the tail end of a body of revolution (BOR) is investigated numerically at Reynolds number of 1.9 × 106 based on the BOR length and free-stream Mach number of 0.059. The turbulent boundary layer on the nose and midsection of the BOR is computed using wall-modeled LES whereas that in the acoustically important tail-cone section under a strong adverse pressure gradient is wall resolved. The radiated acoustic field is calculated based on the Ffowcs Williams-Hawkings equation. The computed flow statistics and sound pressure spectra agree well with the experimental measurements at Virginia Tech. In addition to broadband turbulence-ingestion noise, haystacking spectral peaks near the blade passing frequency and its harmonics are well captured and related to correlated blade interactions with coherent turbulence structures. The accuracy of the classical Sears theory for rotor-noise prediction is evaluated using the upwash velocity field from the LES. The theory is shown to predict well the sound pressure levels at low to mid-frequencies including the haystacking peaks but less accurately at higher frequencies. The spatial and frequency characteristics of blade unsteady-loading dipoles and their correlations are investigated, and the appropriate Mach number scaling for the ingestion noise is identified.
A comparative study of passive compliant coatings in mitigating trailing-edge noise
Authors: Giridhar Rohith , Farokhi Saeed , Taghavi Ray
Published: November 2021

With growing dependence on wind energy as a clean source of electricity, it is imperative to address the shortcomings in modern day wind turbines and ensure their widespread application. One such area to address is the trailing-edge noise from their rotor blades. The present computational study investigates the ability of passive compliant coatings to favorably modulate flow boundary layer and mitigate trailing-edge noise. A flat-plate in fully turbulent flow is chosen to demonstrate this technique. Computational Aeroacoustics Analysis is performed on a flat-plate to predict trailing-edge noise using Ffowcs Williams and Hawkings acoustic analogy for a chord-based Reynolds number of Rec = 460,000. Predicted noise accurately follows the magnitude and trend of measurements for the frequency range of 750—7000 Hz (i.e., Strouhal number St = 5.14—40.00). Accurate prediction of farfield noise demonstrates validity of this approach. Experiments have shown that compliant coatings reduce the amplitude of Tollmien-Schlichting (TS) waves, and enable drag reduction. Two such coatings with different stiffness characteristics are applied on the flat-plate to investigate their ability to offer constructive coupling with flow boundary layer and mitigate trailing-edge noise. Fluid Structure Interaction is employed to simulate coating deformation.
Sonic boom propagation in a non-homogeneous atmosphere using a stratified ray tracing technique
Authors: Riegel Kimberly A. , Costa William , Seaton George , Gomez Christian
Published: November 2021

The propagation of sonic booms in and around large urban areas needs to be well understood in order to determine the impact of the sound will have on the population. Previously a combined ray tracing/radiocity method was developed to model sonic booms around large buildings. While the overall propagation was acceptable, the model had some limitations. One of these limitations was the assumption of a constant speed of sound over the entire propagation area. This updated model uses an atmosphere stratified in the z direction to include the effects of changing temperature in the vertical direction. Another limitation of the previous model is high computation times. As the environment becomes larger and more complicated the computation time becomes very large. To improve computation time and allow for larger, more complex environments, the stratification of the atmosphere was exploited and applied to the environment as well. Only the sections of the building that are within the striation are checked for collisions. This significantly reduces the required computations and simplifies each step of the ray tracing even for complex building configurations. The computation times and pressure using the updated model are presented for several urban environments. The previous model results will be shown as a comparison.
An Introduction to the Technical Committee on Animal Bioacoustics
Authors: Kloepper Laura , Taft Benjamin N.
Published: November 2021

Animal Bioacoustics as a field of research involves the study of sound in non-human animals. The range of this field is wide and includes all aspects of sound production and reception, communication and associated behaviors, acoustic ecology and effects of noise/sound, and passive and active acoustic methods for monitoring individuals, populations, habitats and ecosystems. Members of the Technical Committee on Animal Bioacoustics (TCAB) come from diverse backgrounds, including those with training in biology, ecology, engineering, mathematics, oceanography, physics, and psychology. Many TCAB members also participate in the activities of other ASA Technical Committees including Acoustical Oceanography, Engineering Acoustics, Noise, Psychological and Physiological Acoustics, Signal Processing, and Underwater Acoustics, reflecting the interdisciplinary nature of the field. This talk will highlight some of the popular and emerging areas of research in Animal Bioacoustics.
Speech Communication: Talkers, listeners and signals
Authors: Smiljanic Rajka
Published: November 2021

Speech communication research examines how spoken language is produced, transmitted and perceived. This involves a number of different disciplines, from linguistics and experimental psychology to speech and hearing sciences, and electrical engineering. The field covers a wide range of physiological, psychological, acoustic, and linguistic phenomena. In this presentation, I will highlight some ongoing research in the Speech Communication Technical Committee including work that examines how different challenges to the clarity of the speech signal, such as background noise, interlocutors who are not native speakers of the target language, or hearing loss, affect speech communication. This research has implications for improving communicative effectiveness for various talker and listener groups and human-machine interactions.
Technical Committee on Noise: Researchers and practitioners
Authors: Loubeau Alexandra
Published: November 2021

The Technical Committee on Noise (TCNS) includes researchers and industry practitioners interested in understanding noise generation from a variety of sources, its propagation, and its impact on structures, objects, and people. The goal of reducing the impact of this noise, i.e., unwanted sound, has led to innovative model development, measurement techniques, mitigation strategies, and input towards the establishment of regulations. Community noise definition and abatement is of particular interest and motivates the advancement of research on a variety of topics, such as transportation noise, hearing protection, jet and rocket noise, building systems noise and vibration, atmospheric sound propagation, soundscapes, and low-frequency sound. The diverse technical background of TCNS members is essential, given the interdisciplinary nature of this research, and it is mirrored in the topics of special sessions typically held jointly with other ASA technical committees.
The Technical Committee on Physical Acoustics: Exploration across the acoustic spectrum
Authors: Mobley Joel
Published: November 2021

The Technical Committee on Physical Acoustics (TCPA) is focused on the physics of wave propagation and related phenomena across the entire frequency range of acoustics—from infrasound through ultrasound. Our TC includes a broad range of scientists and engineers involved all in aspects of the study of acoustical phenomena from probing the properties of matter to exploring the physical effects of sound. The TCPA looks to advance not only the science of acoustics but also the methods of investigation whether theoretical, computational or experimental. Due to our broad interests in the underlying physics of wave phenomena, we have a diverse membership who are also involved with a number of other TC’s in the Society. This presentation will discuss all facets of TCPA, and its intersection with other ASA technical areas.
An introduction to the acoustical oceanography technical committee
Authors: Deane Grant B.
Published: November 2021

Underwater acoustics signals, both anthropogenic and natural, are rich sources of information about the ocean interior, the sea surface, and the seafloor. The acoustical oceanography technical committee (AOTC) seeks to foster a broad range of work in pure and applied acoustics aimed at gaining new and fundamental understanding of physical, biological, geophysical, and chemical processes in the ocean and at its boundaries. With this focus, the AOTC is necessarily strongly interdisciplinary, having close ties to other technical committees such as animal bioacoustics, physical acoustics, signal processing, and underwater acoustics. This talk will describe some of the approaches of our members and highlight recent advances in Acoustical Oceanography.
Evaluating noise data from VRF system manufacturers
Authors: Lilly Jerry G.
Published: November 2021

Variable refrigerant flow (VRF) systems are becoming increasingly popular because of improved energy efficiency and the requirement for less HVAC ductwork in the building. This presentation will examine the current acoustic test methods and published sound data for both interior and exterior components of Variable Refrigerant Flow (VRF) systems. It will be shown that the current laboratory test standards vary significantly around the world and often do not provide adequate information for accurately predicting noise levels inside buildings.
Noise control in laboratories
Authors: Rosentel William , Holst Peter
Published: November 2021

ASHRAE Ch. 49 is a leading industry reference in noise control, providing extensive guidance on background noise levels, as well as practical noise control methods. The design guideline for background noise criteria in laboratories ranges from NC 35 to 50 depending on the expected activity. Noise control guidance for laboratories predominantly addresses fume hood design. In practice, recent workplace projects have included laboratory spaces without fume hoods; and background noise levels that are not necessarily controlled by the HVAC systems. The modern definition of “lab” space can include machining and fabrication (makerspaces), workplace server labs (server / chip design), and R&D testing suites for consumer electronics with various microphones/speakers. Accurate estimate of the overall background sound level in the lab is critical in determining appropriate criteria and noise control and avoiding unnecessary cost additions to a project. In some cases (such as makerspaces), ambient noise levels of idling equipment may exceed general ASHRAE guidance and still be acceptable to the occupants, even for a teaching application. In other applications (such as R&D testing), appropriate noise criteria may be significantly lower than ASHRAE’s guidance. This presentation will discuss recent observation and design experiences in evaluating noise levels and noise sensitivity of makerspace, server chip design, and R&D laboratory spaces.
Illuminating finite-amplitude wave propagation: Hargrove’s use of recurrence relations
Authors: Foote Kenneth G.
Published: November 2021

A classic problem in the theory of finite-amplitude wave propagation is that of the spectral evolution of a plane wave. An initial sinusoidal wave becomes triangular, with a vertical face at the shock distance. The wave in the pre-shock regime was represented by a Fourier series in the seminal work by Fubini, i.e., Fubini Ghiron [Alta Frequenza, 4, 530 (1935)]. Independently, Hargrove performed a similar derivation, also invoking recurrence relations for cylindrical Bessel functions, but presenting this with exceptional heuristic clarity and brevity [J. Acoust. Soc. Am. 32, 511 (1960)]. This was coincident with a third paper, by Keck and Beyer [Phys. Fluids 3, 346 (1960)], which knowingly followed Fubini. All of this work has facilitated understanding, providing cogent reminders of the power of recurrence relations when dealing with special functions.
The critical role of Logan Hargrove in establishing the physical acoustics summer school
Authors: Gladden Joseph
Published: November 2021

First established in 1988, the Physical Acoustics Summer School (PASS) was patterned off of a long tradition in European scientific communities of carving out a week or more for established scientists and graduate students to come together in a remote location in order to focus on the state of the science and build community between existing and emerging generations of thought leaders. PASS has convened every two years from that time until a global pandemic disrupted that in 2020. During those early years, Logan Hargrove was an enthusiastic and energetic supporter of physical acoustics research, but had a vision to build a program to support the field beyond funding individual research projects through ONR—he wanted to support a vibrant and long-term physical acoustics community. Logan’s vision is now a well-established reality and still guides the planning and organization of PASS today. In this talk, I will present some of the history of PASS and its evolution over the years with a focus on Logan’s critical role all along the way.
Virtual sound source distance evaluation in acoustically and visually incongruent contexts
Authors: Martin Vincent , Warusfel Olivier , Viaud-Delmon Isabelle
Published: November 2021

Visual and acoustic environment may influence the perception of auditory distance. In the context of Audio-only augmented reality (AAR), the coherence of the perceived virtual sound sources with the apparent room geometry and acoustics cannot always be guaranteed. The perceptual consequences of these incoherences are not well known. We conducted two online perceptual studies with a sound distance rendering model based on measured spatial room impulse responses (SRIR). A first study evaluated the perceptual performances of the model in incongruent visual contexts. The incongruent environment-related visual cues (spatial visual boundary and room volume) demonstrated a significant effect on the auditory distance perception (ADP) of virtual sound sources, through a calibration effect. A second study evaluated the impact of acoustical incongruence. Virtual sound sources distances were judged after the participant listened to distracting sound sources conveying distance cues relative to a different acoustical environment. When this distracting sound sources corresponded to a larger room than the one reproduced by the model, a higher compression effect was observed on the ADP of virtual sound sources. However, when the intensity cue conveyed by the distracting sound sources were coherent with the acoustical environment simulated by the model, their distracting effect were negligible.
Measurements and models for tone localization by moving listeners
Authors: Hartmann William , Macaulay Eric
Published: November 2021

Listeners were given the challenging task of localizing a steady-state sine tone in a moderately reverberant room. Listeners attempted to optimize performance by moving during the nine-second tone interval. To discover listener localization strategies, the experiment acquired complete records of listener head motion (Polhemus head tracker) and the signals in the ear canals (Etymotic probe tubes). Experiment data were used to test two models of sound localization by moving listeners: According to the “Relative Null" model, listeners search for nulls in relevant interaural differences and use the momentary nose orientations where these nulls occur as indicators of source azimuth. According to the “Inferred Azimuth" model, listeners acquire a continuous, long-term record of inferred source location based on momentary head orientation combined with corresponding interaural differences. Models include different cue weighting assumptions and are evaluated by their ability to predict listener responses. The Relative Null model proves to be more accurate, but sometimes fails to make a prediction. The Inferred Azimuth model always makes multiple predictions, and often leads to further insights. These models are the most straightforward of numerous possibilities. Alternatives that weight the time course of listener cues, should be considered.
Forward masking of amplitude modulation detection includes a large perceptual effect
Authors: Conroy Christopher , Byrne Andrew J. , Kidd Gerald
Published: November 2021

Forward masking of amplitude modulation (AM) detection is tuned: target sinusoidal AM (SAM) is masked more easily by masker SAM with a similar, rather than dissimilar, rate. This finding has been interpreted either as a sensory effect related to adapting neural units tuned to the target’s AM rate, or as a perceptual effect related to the perceived similarity of the acoustically similar AM. This study investigated these two alternative possibilities. The minimum modulation depth required to detect 96-Hz target SAM was measured following exposure to suprathreshold masker AM applied to the same broadband-noise carrier. Three forward masker modulators were tested: (1) 32-Hz SAM; (2) a 32-Hz square wave; (3) and 96-Hz SAM with a modulation index equivalent to that of the third harmonic of the square wave. The 96-Hz masker SAM produced substantial amounts of forward masking; the 32-Hz sine- and square-waves, however, did not. These findings were inconsistent with the hypothesis that detection of the target SAM was mediated by adapting neural units tuned to the target’s AM rate, suggesting, instead, that forward masking of AM detection includes a large perceptual effect.