bluuebunny/crossref_metadata_2025 huggingface dataset:
Product Competition Prediction in Engineering Design Using Graph Neural Networks
Authors: Ahmed Faez , Cui Yaxin , Fu Yan , Chen Wei
Published: May 2022

Understanding relationships between different products in a market system and predicting how changes in design impact their market position can be instrumental for companies to create better products. We propose a graph neural network-based method for modeling relationships between products, where nodes in a network represent products and edges represent their relationships. Our modeling enables a systematic way to predict the relationship links between unseen products for future years. When applied to a Chinese car market case study, our method based on an inductive graph neural network approach, GraphSAGE, yields double the link prediction performance compared to an existing network modeling method—exponential random graph model-based method for predicting the car co-consideration relationships. Our work also overcomes scalability and multiple data type-related limitations of the traditional network modeling methods by modeling a larger number of attributes, mixed categorical and numerical attributes, and unseen products. While a vanilla GraphSAGE requires a partial network to make predictions, we augment it with an “adjacency prediction model” to circumvent the limitation of needing neighborhood information. Finally, we demonstrate how insights obtained from a permutation-based interpretability analysis can help a manufacturer understand how design attributes impact the predictions of product relationships. Overall, this work provides a systematic data-driven method to predict the relationships between products in a complex network such as the car market.
Zonal Detached Eddy Simulation of the Fan-Outlet Guide Vanes Stage of a Turbofan Engine: Part I—Methodology, Numerical Setup, and Aerodynamic Analysis
Authors: François Benjamin , Polacsek Cyril , Barrier Raphaël
Published: May 2022

This article deals with the zonal detached eddy simulation of the fan module of a modern turbofan engine for the prediction of the broadband noise due to the interaction of the fan turbulent wakes with the stationary outlet guide vanes. The simulation relies on a hybrid RANS/LES approach with a zonal strategy: the core airflow is treated in RANS, while the bypass airflow is solved with the hybrid approach. The simulation was performed during four revolutions, and statistical convergence was reached. Inspections of the flowfields highlight a consistent behavior of the shielding function (border between RANS and LES solving areas) around the blade walls and at the trailing edge for a such complex flow. The fan module was tested in the AneCom facility in which hot wire measurements were made in-between the fan and the outlet guide vanes. The numerical results are compared to this large dataset of measurements. The flow maps are well retrieved by the simulation for both the time-averaged and the turbulent quantities. Comparison of radial profiles shows an excellent agreement for the three root-mean-square (RMS) components of the velocities between zonal detached eddy simulation (ZDES) and the measurements, particularly in the tip gap flow area, in which RANS results do not reproduce correctly the flow quantities. The wake shape, a key feature in the mechanism of generation of rotor–stator interaction noise), is quite well predicted by the ZDES simulation. These numerical results demonstrate the maturity of the approach for the simulation of complex turbomachinery flows.
Effect of Interfacial Tension on Relative Permeability Curves Obtained by Considering Surfactant Adsorption and Diffusion
Authors: Zhang Wenlong , Hou Jian , Liu Yongge , Cao Weidong , Zhou Kang , Du Qingjun
Published: May 2022

To consider the effect of adsorption and diffusion of surfactant on relative permeability, a method for estimating the relative permeability was developed by matching production data obtained through an unsteady-state core flooding experiment and numerical simulation. After the robustness of the method was proven, the necessity of considering surfactant adsorption and diffusion in calculating the relative permeability was proven. Compared with relative permeability curves obtained by neglecting surfactant adsorption and diffusion, the average error of the relative permeability curve obtained by considering surfactant adsorption and diffusion decreases from 11.5% to 3.5% for the oil phase and from 13.1% to 4.2% for the aqueous phase. Finally, the effects of interfacial tension (IFT) on relative permeability curves obtained by considering surfactant adsorption and diffusion were studied. The results show that surfactant adsorption and diffusion affect the relative permeability but not the change in the relative permeability curves for varying IFT. The individual relative permeability curve does straighten with decreasing IFT. As the IFT decreases in a semilog plot, the relative permeability values at the equal-permeability point (i.e., the same relative permeability for oil–water) and residual oil endpoint increase following a logistic function and an exponential function, respectively.
Strongly interacting trapped one-dimensional quantum gases: Exact solution
Authors: Minguzzi A. , Vignolo P.
Published: May 2022

Understanding the effect of correlations in interacting many-body systems is one of the main challenges in quantum mechanics. While the general problem can only be addressed by approximate methods and numerical simulations, in some limiting cases, it is amenable to exact solutions. This Review collects the predictions coming from a family of exact solutions which allows us to obtain the many-body wavefunction of strongly correlated quantum fluids confined by a tight waveguide and subjected to any form of longitudinal confinement. It directly describes the experiments with trapped ultracold atoms where the strongly correlated regime in one dimension has been achieved. The exact solution applies to bosons, fermions, and mixtures. It allows us to obtain experimental observables such as the density profiles and momentum distribution at all momentum scales, beyond the Luttinger liquid approach. It also predicts the exact quantum dynamics at all the times, including the small oscillation regime yielding the collective modes of the system and the large quench regime where the system parameters are changed considerably. The solution can be extended to describe finite-temperature conditions, spin, and magnetization effects. The Review illustrates the idea of the solution, presents the key theoretical achievements, and the main experiments on strongly correlated one-dimensional quantum gases.
Gold Medal 2022: Michael J. Buckingham
Authors: Buckingham Michael J.
Published: May 2022

The Gold Medal is presented in the spring to a member of the Society, without age limitation, for contributions to acoustics. The first Gold Medal was presented in 1954 on the occasion of the Society's Twenty-Fifth Anniversary Celebration and biennially until 1981. It is now an annual award.
Experimental study on the quasi-steady approximation of glottal flows
Authors: Honda Takuto , Kanaya Mayuka , Tokuda Isao T. , Bouvet Anne , Van Hirtum Annemie , Pelorson Xavier
Published: May 2022

To examine the quasi-steady approximation of the glottal flow, widely used in the modeling of vocal fold oscillations, intraglottal pressure distributions were measured in a scaled-up static vocal fold model under time-varying flow conditions. The left and right vocal folds were slightly open and set to a symmetric and oblique configuration with a divergence angle. To realize time-varying flow conditions, the flow rate was sinusoidally modulated with a frequency of 2 and 10 Hz, which correspond to 112.5 and 562.5 Hz, respectively, in real life. Measurements of the intraglottal pressures under both steady and time-varying flows revealed that the pressure profiles of the time-varying flow conditions are non-distinguishable from those of the steady flow conditions as far as they have the same subglottal pressure as an input pressure. The air-jet separation point was also non-distinguishable between the steady and the time-varying flow conditions. Our study therefore suggests that the time-varying glottal flow can be approximated as a series of steady flow states with a matching subglottal pressure in the range of normal vocalization frequencies. Since the glottal closure was not taken into account in the present experiment, our argument is valid except for such a critical situation.
Effect of speech-related smile suppression on emotional valence
Authors: Ebbutt Nicole , Hung Kyra , Ivok Magdalena , Purnomo Charissa , Samir Farhan , de Boer Gillian , Gick Bryan
Published: May 2022

The physical act of smiling has direct positive effects on mood [Kleinke et al., Pers. Soc. Psychol. 74, 272–279 (1998)]. Relatedly, Rummer et al. [Emotion, 14(2), 246–250 (2014)] observed that participants rated comics as funnier if they had just produced /i/ (which requires adopting a smile-like position) than if they produced /o/. The present study tests whether suppression of smile posture by speech movements can cause individuals to view a subject less positively. To do so, we ask participants to maintain a smile while we present a series of visual stimuli labeled with target and control sounds. Bilabial sounds are targeted as Liu et al. found that bilabial stops (/p/ and /b/) suppress smile posture [ISSP12, 130–133 (2021)]. After articulating a sound that either suppresses or does not suppress their smile posture, participants rate each image set on a measure of emotion. Results will be presented and discussed bearing on the prediction that in the smile condition, participants will rate the image as less positive if they have just produced a sentence which includes a bilabial stop. [Work supported by NIH and NSERC.]
Microbubble dynamics in brain microvessels at 1 MHz and 330 kHz driving frequencies
Authors: Bezer James H. , Prentice Paul , Lim Kee Chang William , Jiang Zheng , Morse Sophie , Rowlands Christopher , Christensen-Jeffries Kirsten M. , Kozlov Andrei , Choi James
Published: May 2022

Blood-brain barrier (BBB) disruption using ultrasound-driven microbubbles is a promising technique to deliver drugs to the brain. This study aimed to directly observe behaviours of individual microbubbles within the brain microvasculature when exposed to pulses typical in transcranial ultrasound therapy. Low centre frequencies of 1 MHz and 330 kHz were used, at mechanical indices of 0.2-1, and pulse lengths up to 10 ms. Acute brain slices were obtained from juvenile rats, transcardially perfused with SonoVue, heparin, and dye. In each slice, a suitable bubble in a microvessel (5–15 μm diameter) was observed at both microsecond and millisecond time scales during ultrasound exposure. Oscillating microbubbles cause microvessel walls to distend and invaginate at the ultrasound driving frequency and can cause micrometre-scale tissue displacements well beyond the endothelial wall. Microbubbles can also be forced out of small microvessels due to the primary radiation force; this occurred at both frequencies tested. The probability of extravasation scales approximately with mechanical index, being rare at low pressures, but much more common at MI ≥ 0.6. Microbubble extravasation due to the primary radiation force may, therefore, be a mechanism of BBB disruption or of tissue damage. These results may aid development of safer and more effective therapies.
A three-dimensional human brain spheroid model for studying sonoporation-induced drug penetration beyond the blood-brain barrier
Authors: Paranjape Anurag N. , D’Aiuto Leonardo , Zheng Wenxiao , Chen Xucai , Villanueva Flordeliza S.
Published: May 2022

Ultrasound (US)-targeted microbubble (MB) cavitation (UTMC) facilitates delivery of cell-impermeant drugs across the blood brain barrier (BBB). The effects of UTMC on extravascular cells, and the extent of payload penetration, are unknown. Spheroids were generated using neurons and astrocytes derived from human iPSCs, primary human brain- microglia, endothelial cells (ECs) and pericytes, and placed in a water tank with lipid MBs. US (1 MHz frequency, 250 kPa peak negative pressure, 10 μs pulse duration, 10 ms pulse interval) was delivered for 10 s. Immunostaining showed ECs and pericytes at the spheroid periphery, with high expression of membranous ZO-1. BBB functionality was confirmed with histamine treatment, which increased permeability to Texas red dextran (TRD) (28.8% increase, p = 0.0015). TRD penetrated up to 100 μm beyond the BBB upon UTMC (12% increase compared to 0 kPa control). Inhibition of endothelial nitric oxide synthase with L-NAME reduced UTMC-induced TRD penetration (19% decrease, p < 0.05). Sonoporation, as shown by uptake of propidium iodide, occurred in cells beyond the BBB. In our novel 3D spheroid model with intact BBB, UTMC caused nitric-oxide dependent BBB breach. This is the first report of UTMC causing “remote” sonoporation of cells not in direct contact with MBs and bears further study.
The spatial distribution of the ligand on targeted microbubbles influences the binding efficacy
Authors: Langeveld Simone A. G. , Meijlink Bram , Beekers Ines , Olthof Mark , van der Steen Antonius F. , de Jong Nico , Kooiman Klazina
Published: May 2022

An important trait of targeted microbubbles is their binding to biomarkers for ultrasound molecular imaging and drug delivery. Using organic solvents in phospholipid-coated microbubble production results in a homogeneous ligand distribution, while dispersion of lipids directly into aqueous medium results in a heterogeneous ligand distribution. In this study, we compared the binding efficacy of ανβ3-targeted microbubbles with a homogeneous or heterogeneous ligand distribution in vitro and in vivo using confocal microscopy. For in vitro studies, human umbilical vein endothelial cells grown statically and under physiological flow were used. For in vivo studies, chicken embryos (day 5) were used. Microbubbles having a homogeneous ligand distribution bound 1.55× more than microbubbles having a heterogeneous ligand distribution in vitro statically, while in vitro under flow this was 1.49× more at 1.25 dyn/cm2 and 1.56× more at 2.22 dyn/cm2; in vivo this was 1.25× more. The dissociation rate in vitro was lower for bound microbubbles with a homogeneous than heterogeneous ligand distribution at low shear stresses (1–5 dyn/cm2). In conclusion, when producing phospholipid-coated targeted microbubbles using organic solvents is preferable over directly dispersing phospholipids in aqueous medium for optimal binding. [Funding by the Phospholipid Research Center (No. KKO-2017-057/1-1) and NWO (VIDI Project No.17543) is gratefully acknowledged.]
Ultra-high speed quantification of cell strain during cell-microbubble interactions
Authors: Pattinson Oliver , Carugo Dario , Pierron Fabrice , Evans Nicholas
Published: May 2022

Interactions between oscillating microbubbles and cells are of fundamental importance in understanding cell behaviour, including mechanotransduction, during therapeutic microbubble treatment. However, it is challenging to quantify cell deformation due to the short time domains at which microbubble-induced deformations occur. Developments in both ultra-high speed imaging and image processing may allow for quantification of cell strain at high temporal and spatial resolutions. Here, we tested the hypothesis that ultra-high speed imaging and digital image correlation could be used to measure and quantify microbubble-induced cell deformation. A hypervision HPV-X camera and a custom-designed, compact acoustic cell-culture device were used together to image interactions between DSPC-microbubbles and MG-63 cells at up to 5 × 106 fps, under ultrasound exposure at 1 MHz. Dynamic cell deformation was measured using digital image correlation with MatchID software. Microbubbles associated with MG63 cells in the acoustic device. Microbubble oscillation resulted in a peak deformation of 350 nm and strain of 5% on the cell during the bubble expansion phase, isolated locally to the point of interaction. These data show that cell deformation can be quantified dynamically during bubble-cell interactions, suggesting that mechanical properties, and potentially corresponding therapeutic effects, can be quantified at high-frequency strain rates.
Multichannel frequency-selective beaming in time-modulated electroacoustic phased arrays
Authors: Nouh Mostafa
Published: May 2022

Acoustic phased arrays have been a cornerstone of non-destructive evaluation, sonar communications, and medical imaging for years. Conventional arrays work by imparting a static phase gradient across a set of acoustic transceivers to steer a self-created wavefront in a desired direction. In a reception mode, they abide by basic reciprocity principles and exhibit the strongest gain for waves incident from the same direction to which they transmit. This talk sheds light on a class of dynamic phased arrays which is capable of (a) generating multiple scattered harmonics of a single-frequency voltage input which simultaneously propagate in different directional lanes and (b) exhibiting non-identical TX/RX patterns. We will show that such lanes emerge in the form of artificially-synthesized directional channels each with a distinct frequency signature that can be predicted a priori. To achieve this, we devise a class of phase shifters, which augment the array elements with a dynamic phase modulation using an array of piezo-wafer discs bonded to an elastic medium. The scattered beams propagate simultaneously in the transmitted wave field but can be visualized using an FFT of the time-transient measurements via laser Doppler vibrometry. The experimental realization illustrates the array’s ability to guide incident waves within tunable frequency channels that are commensurate with the modulation rate and along the intended directions.
Dynamics of temporally modulated materials: Adiabatic transformations and frequency conversion
Authors: Riva Emanuele
Published: May 2022

The recent progress in the context of elastic metamaterials and modulated waveguides with digitally controllable properties has spurred the research in the context of time-varying and space-time varying mechanical systems. In other words, the search of new functionalities, such as nonreciprocity, frequency conversion, parametric amplification, and edge-to-edge pumping, to name a few, requires advanced space-time control of the material parameters, which justifies the emergence of active times in phononics. The work presented herein discusses temporal modulations in the context of stiffness-modulated elastic structures, with emphasis on frequency conversion and wave steering. It is shown that slow temporal modulations, compliant with the adiabatic theorem, can be functionally employed to change the frequency content and the propagation direction of incident wave packets. At the same time, adiabatic variations avoid the scattering of back-propagating waves, which are instead present in case of fast modulations and, in many cases, can be undesired from a practical perspective. Both transient and steady-state behaviors of stiffness-modulated waveguides are discussed with the goal of achieving controllable transmission of elastic signals between an emitter and a receiver.
Electromechanical metastructures for simultaneous wave attenuation and energy harvesting
Authors: Tol Serife
Published: May 2022

Periodic architectures designed with piezoelectric materials are favorable due to their potential to control waves without any need for structural modifications and also due to their multifunctional abilities, such as energy harvesting and vibration mitigation. This talk focuses on the latter and introduces a piezoelectric-based metastructure with broadband capability of low-frequency elastic wave energy conversion. Unlike the phononic crystal concepts consisting of piezoelectric patch arrays with heavy masses or resonance-based piezoelectric cantilever harvester arrays with tip mass attachments used for harvesting standing waves, our goal is to exploit the properties of locally-resonant metamaterials and phononic crystals within the same structure and harvest energy from travelling elastic waves. Specifically, we merge locally resonant and Bragg band gaps to achieve a multifunctional metastructure, which is capable for maximum energy conversion and wave attenuation in a broadband fashion. To this end, we develop a new wave-based fully coupled electroelastic transfer matrix method and study multifunctional harvesting and attenuation performance of the electromechanical metastructure. The theoretical frameworks and the applicability of the proposed metastructure are also validated using a full-scale experimental setup.
Nonreciprocal acoustic scattering from an elastic plate with spatiotemporally modulated material properties
Authors: Goldsberry Benjamin M. , Wallen Samuel P. , Haberman Michael R.
Published: May 2022

Acoustic and elastic metamaterials with space- and time-dependent material properties have received great attention recently as a means to realize nonreciprocal wave propagation. The nonreciprocal behavior of propagating waves in a spatiotemporally modulated infinite medium is usually characterized by directional bandgaps present in the frequency-wavenumber spectrum. However, less attention has been given to acoustic scattering from spatiotemporally modulated media. In this work, we consider nonreciprocal reflection and transmission from a spatiotemporally modulated, infinite elastic plate excited by a plane wave at oblique incidence. A semi-analytical approach is developed that considers the coupling between the acoustic waves and the displacement of the plate. The reflection and transmission response of the plate for each generated frequency harmonic as a function of the incident angle are reported. Finally, we find conditions on the modulation parameters that yield a large degree of nonreciprocity. The present analysis leads to potential applications in acoustic communications, such as directional wave sensing.
Modeling of acoustic and gravity wave interactions, coupling, and observables above meteorological systems
Authors: Snively Jonathan B. , Sabatini Roberto , Calhoun Donna A. , Heale Christopher J. , Inchin Pavel A. , Zettergren Matthew D.
Published: May 2022

Meteorology, especially strong tropospheric convection, is widely appreciated to generate broad spectra of acoustic and gravity waves (AWs and GWs or, together, AGWs). These include GWs with scales of tens to hundreds of kilometers and periods of ∼5 min to hours, that readily propagate upward, reach high altitudes (often to the lower-thermosphere), and grow to large amplitudes so that they may evolve nonlinearly prior to being overcome by dissipation. Strong convective dynamics, e.g., thunderstorms and tornadoes, are also known to radiate AWs at very low infrasonic frequencies (e.g., 0.1 Hz down to ∼4 mHz) that reach high altitudes and may be detectable in fluctuations of the atmosphere and ionosphere [e.g., Nishioka et al. (2013); Heale et al. (2019)]. The breaking of strong GW fields may also generate secondary AWs and, more generally, AGWs [Snively (2017); Heale et al. (2021)]. Together, convection and secondary AGW processes contribute to a broad spectrum of AWs with ∼mHz periods that are readily detectable at high altitudes and in pressure signals also measured at ground. Although AWs are excluded from traditional numerical weather prediction models, we report on models and simulation experiments designed to capture AW/AGW evolutions and their resulting observable signatures. In particular, we review and highlight scenarios by which ∼mHz AWs may reveal source processes of interest, as well as the opportunities to use atmospheric and ionospheric signals of AWs/AGWs as complement to ground-based infrasound recordings.
Front-back reversals for tones heard in a room by moving listeners
Authors: Hartmann William , Magann Jack C. , Macaulay Eric
Published: May 2022

The tone localization experiments reported by Macaulay and Hartmann [J. Acoust. Soc. Am. 149, 4159–4179 (2021)] were highly biased in favor of sources in front of the listener. Nevertheless, listeners sometimes localized tones in back, both when they were stationary and when they were required to move. The experiments provided extensive data relevant to the matter of in-back localization, because they measured head location and orientation as well as ear canal signals throughout each experiment trial. Because the experiments were done in a room, the data were irregular functions of source azimuth. Analysis revealed the following effects: For stationary trials, back responses were strongly correlated with weaker tone levels in the ear canals for 500, 2000, and 4000 Hz. Correlation was greatly reduced at 1000 Hz. That result is consistent with head-related transfer functions, where ear-canal intensity is greater for sounds in front except near 1000 Hz. For moving trials, back responses at 500 and 1000 Hz were strongly correlated with the slopes of interaural level differences and interaural time differences as functions of head-pointing direction, as naturally occur in free field. Correlations decreased dramatically at higher frequencies.
Is acoustic space “learned” in the buildup of the precedence effect?
Authors: Pastore M. Torben , Yost William A. , Zhou Yi
Published: May 2022

Most of what is known about sound source localization in reverberant environments rests upon knowledge of how the auditory system processes a pair of brief stimuli presented over headphones that simulate a direct sound and a single reflection. In everyday environments, however, sound sources often emit relatively continuous sounds or repeat them often in succession—for example, speech. Also, listeners often move. Dynamic changes in source/listener positions may present a unique opportunity to investigate the effects of “learning” that seem to result in the “buildup of the precedence effect—listeners' ability to effectively localize reverberant sounds after repeated presentation that would be poorly localized after only one presentation. The implicated learning may constitute learning of the spatial acoustics of the environment or learning of the temporal order and timing of reflections (or both). In this study, we sought to disambiguate these two possible learning strategies by comparing listener behavior in response to presentation of repeated pairs of lead/lag noise stimuli presented in a soundfield. Listeners’ perceived sound-source localization and the rate of fusion were measured.
A sex difference and learning in the discrimination of interaural-level differences but not interaural-time differences in naïve listeners
Authors: Wright Beverly A. , Dai Huanping
Published: May 2022

The two primary cues to sound-source location on the horizontal plane are interaural differences in time (ITDs) and in level (ILDs). Here, we asked whether the ability to discriminate small changes in each of these interaural cues differs between the sexes. We tested males and females who had no prior experience with any psychoacoustic task on either ILD discrimination at 4 kHz or ITD discrimination at 0.5 kHz. For ILD discrimination, the overall mean threshold, as well as the threshold for each 50-trial block, was significantly lower for males (n = 80) than for females (n = 166). Both males and females learned over the course of testing, but there was no sex difference in learning rate. In contrast, for ITD discrimination, thresholds did not differ significantly between the sexes for the overall mean or for any block (n = 43M/94F). There also was no learning across blocks for either group. For both tasks, the individual thresholds spanned a wide range in each group. The presence of sex differences and learning for ILD but not ITD discrimination suggests that the factors responsible for these outcomes influenced a relatively peripheral ILD-specific pathway, and not an ITD-specific pathway, or a more central locus that is not cue specific.
Visual capture and changes in response times in multisensory localization tasks
Authors: Clayton Colton , Zhou Yi
Published: May 2022

In the real-world, environmental objects are often both seen and heard. Visual stimuli can influence the accuracy, variability, and timing of the listener’s responses to auditory targets. One well-known example of this visual influence is the Ventriloquist Illusion or visual capture of the perceived sound source location. However, less is known about how vision affects the timing of sensorimotor output driven by auditory events. We hypothesize that response time may manifest the influences of two different visual factors—stimulus features (e.g., spatial congruence) and environmental features (e.g., contextual reference). We measured eye saccades, a natural orienting behavior, in response to auditory and visual stimuli with different degrees of spatial alignment in two visual environments (with or without contextual reference). Results showed both visual factors can influence the timing of saccades to auditory targets. Response time was longer when auditory, and visual signals are spatially separated. Response time was also longer in the non-referenced than referenced environments, but the effect size was small. These results demonstrate response time as a valuable metric for understanding multisensory perception. Further studies are needed to investigate the patterns of changes in both response time and response accuracy to gain new insights into auditory localization in real-life settings.
Spectral weighting functions for localization of complex sound: Effects of sensorineural hearing loss
Authors: Folkerts Monica L. , Picou Erin M. , Stecker G. Christopher
Published: May 2022

When localization cues are distributed across the spectrum of a complex sound, listeners with normal hearing (NH) utilize cues near the 600-800 Hz “ITD dominance region” [Bilsen and Raatgever, Acustica 28, 131–132 (1973)]. Recent work has quantified this pattern using spectral weighting functions (SWFs) [Folkerts and Stecker, ARO 42, 505 (2018)] in NH listeners. However, the salience of the ITD dominance region in listeners with sensorineural hearing loss (SNHL) remains unexamined. Folkerts and Stecker [ARO 45, 171 (2022)] used simulated SNHL in NH listeners to measure impacts of elevated hearing thresholds, loudness recruitment, and reduced high-frequency ITD sensitivity [Steinberg and Gardener, J Acoust. Soc Am 9, 11–23 (1937)] on SWFs. The current study measured SWFs in listeners with bilateral sloping high-frequency SNHL. Direct comparisons to SWFs measured with simulated SNHL test the hypothesis that reduced audibility of high-frequency components shifts the ITD dominance region to lower frequencies (i.e., 400–600 Hz). Individual SWFs measured in listeners with SNHL are compared to their headphone and free field thresholds to assess whether audibility can account for weighting changes. [Work supported by NIH R01-DC016643.]
A creeping-wave elliptic-head model that explains non-monotonic envelope interaural time differences
Authors: Mayo Paul G. , Brown Andrew D. , Goupell Matthew J.
Published: May 2022

Interaural time and level differences (ITDs and ILDs) created by interactions of impinging sound with the head facilitate horizontal-plane sound localization. ILDs are known to be non-monotonic functions of azimuth, resulting in predictable mislocalization of tonal sources at some frequencies, while ITDs are typically construed as monotonic functions of azimuth. However, recent measurements using a binaural mannequin revealed envelope ITDs (ENV-ITDs) that were non-monotonic functions of azimuth, with the extent of nonmonotonicity dependent on carrier frequency. This study proposes that delayed sound traveling around the back of the head causes this phenomenon. ENV-ITDs created by a time-dependent model of incident sound waves propagating around the front and back of an elliptical head were compared to ENV-ITDs computed using publicly available HRTF libraries for a broadband speech excitation signal. Results from the model align with data from the HRTF libraries, with nonmonotonicities in the ENV-ITD-azimuth functions occurring at nearly identical azimuths and frequencies. These data suggest the veracity of this phenomenon and may have implications for spatial hearing abilities. They also suggest that time-independent models of ITDs that only consider frequency and incident angle, such as spherical head or circular arc length models, could be updated to include such time dependence.
Factors influencing performance on the modified rhyme test by noise-exposed service members
Authors: Brungart Douglas S.
Published: May 2022

Two speech-in-noise experiments using stimuli from the modified rhyme test (MRT) were conducted on service members (SMs) in conjunction with their annual hearing tests. The first experiment, involving roughly 3200 SMs, compared performance in the standard diotic headphone-presented MRT test to the performance level that could be achieved if the same MRT stimuli were presented from a single wall-mounted speaker in one of two different clinical sound booths. The second experiment, involving roughly 2000 SMs, examined performance in a headphone-presented MRT paradigm where the target talker was presented monaurally and the ITD ofthe masker alternated between −800 μs and + 800 μs at a 4 Hz rate. Pure-tone audiometric thresholds, N0Sπ detection thresholds, and subjective surveys of hearing difficulty and noise exposure were collected for all participants in both studies. The results show that MRT scores and response times both vary systematically with subjective hearing difficulty, suggesting that a composite time-accuracy score might be the most effective way to evaluating performance on the MRT. The results also provide insights into the hearing difficulties frequently experienced by noise- and blast-exposed service members with normal or near-normal hearing thresholds. [The views expressed in this abstract are those of the author and do not reflect the official policy of the Department of Defense or U.S. Government.]
Contralateral unmasking for single-sided-deafness cochlear-implant users with shifted frequency assignments to reduce interaural place mismatch
Authors: Bernstein Joshua G. , Eitel Megan M. , Phatak Sandeep A. , Jensen Kenneth , Pillion Elicia M. , Dirks Coral , Goupell Matthew J.
Published: May 2022

For cochlear-implant (CI) users with single-sided deafness (SSD), standard clinical programming yields interaural place-of-stimulation mismatch, because the electrode array does not reach the apex. This mismatch might degrade spatial-hearing abilities. This study examined whether acutely presented alternative frequency-to-electrode assignments (“remapping”), designed to reduce mismatch, could improve the use of two ears together to perceptually separate competing talkers. Remapped frequency assignments were derived from computed-tomography scans of intracochlear electrode locations or psychophysical tuning curves for interaural time-difference discrimination. Contralateral unmasking was measured by presenting target speech (closed-set corpus) to the acoustic ear and two same-sex competing talkers to just the acoustic ear or to both ears. Preliminary results (N = 8/15 planned subjects) show that for seven subjects with small (≤3-dB) initial binaural benefit, remapping yielded a small but significant (0.5-dB mean) increase in binaural benefit. Remapping was detrimental for the one subject with large (6-dB) initial binaural benefit. Possible longitudinal effects and tradeoffs with other SSD-CI hearing benefits that could be affected by remapping are discussed. [The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army/Navy/Air Force, Department of Defense, or U.S. Government.]
A structural modification analysis framework leveraging the Lagrange multiplier frequency based substructuring Method
Authors: Bonomo Anthony L. , Cullen Robert T.
Published: May 2022

In 2006, de Klerk, Rixen, and de Jong introduced the Lagrange multiplier frequency based substructuring method (LM FBS) as an alternative to the classical frequency based substructuring method (FBS). LM FBS has several advantages over FBS, as it easier to implement and more efficiently handles problems with more than two substructures. LM FBS has also been shown to be quite adaptable and has recently been extended to include flexible connection elements at the interfaces between substructures. One other advantage of the LM FBS that has not been fully exploited to date is the fact that the dimension of the mobility matrix of the coupled system remains the same as the block-diagonal uncoupled system. This feature allows the LM FBS to be more easily interpreted in terms of structural modification and offers the analyst the option to use the normal modes of the uncoupled system as a basis for tracking and quantifying the influence of substructure coupling on the dynamic response of the coupled system. This talk will demonstrate such a structural modification framework utilizing LM FBS.
Radiation of thin complex plates estimated with the landscape of localisation theory
Authors: García A. Carlos , Dauchez Nicolas , Lefebvre Gautier
Published: May 2022

The landscape of localisation is a practical tool that enables the prediction of the geographical localisation of localized modes and helps us to understand the transition between localized and delocalised states. Moreover, approximations based on the Rayleigh quotient and on a variant of Weyl’s law are employed to predict the eigenfrequencies for the Schro ¨ dinger operator in quantum mechanics, but they are also valid for the Laplace and biharmonic operators, which characterize the behaviour of most dynamical systems in acoustics and vibrations. When studying the acoustic radiation from a vibrating structure, three global parameters are key indicators: the mean squared velocity, the acoustic radiated power, and the radiation efficiency. The literature on this subject is very vast for the plate case, where for simple geometries, it is still possible to derive analytical solutions or, at least, very useful approximations. For more complex structures, numerical simulations seem to be appropriate for lack of a simpler solution. In this context, this work aims to give some light to create a direct relationship between these global parameters and the landscape of localisation function, based on the multipolar radiation behaviour presented by localized modes and estimated by geometrical means.
Pediatric speech understanding in noise and the role of working memory andcomprehension
Authors: Sullivan Jessica
Published: May 2022

Working memory is vital to a child’s cognitive processing and speech understanding in noise. More recent findings suggest that the relationship between speech recognition in noise and auditory comprehension may be capturing difficulties in understanding speech in noise which have been linked to cognitive and linguistic skills. Children’s auditory-cognitive performance is highly sensitive to processing load. The extent that children engage cognitive resources depends on demands of task difficulty and intensity level of four-talker babble. The combined costs of performing a difficult task in adverse acoustical conditions are greater than the sum of the individual costs. This suggest that the relationship between speech recognition in noise and auditory comprehension may be capturing difficulties in language which may have effects in academic success. Data will be presented (1) show that audibility alone does not account for difficulties in speech perception in noise (2) showing the complex relationship between working memory and auditory comprehension. (3) Implications for clinical speech in noise screener for children. While app-based interventions for speech and language exist, to our knowledge, none explicitly screen for perception of speech in the presence of noise.
Intelligibility of dysphonic speech in primary schools
Authors: Murgia Silvia , Mekus Taylor , Bottalico Pasquale
Published: May 2022

School children need clear auditory signals and low background noise to learn. When classroom acoustics are poor, teachers often compensate by raising their voices, usually with limited effect against background noise, and, long-term, this makes vocal overuse the primary cause (60%) of the high prevalence of voice problems in teachers. Speech intelligibility tests were performed in primary schools with normal hearing students using words produced by an actor with normal voice quality and simulating a dysphonic voice. The speech was played by a Head and Torso Simulator. Artificial classroom noise and classrooms with different reverberation times were used to obtain a range of Speech Transmission Index from 0.2 to 0.7 (from bad to good). Results showed a statistically significant decrease in intelligibility when the speaker was dysphonic with a maximum of 15% intelligibility loss. This study extends an important pairing of problems related to student learning: classroom acoustics and teachers with voice disorders. It provides important insights into the enormous variability in speech intelligibility in classrooms by characterizing students’ intelligibility when students receive degraded auditory input. The degraded auditory input results from the intersection of classroom acoustics and poor teacher voice quality
Modeling parallel arranged transparent micro-perforated panels to enhance low-mid frequency sound absorption
Authors: Yilmazer Semiha , Fasllija Ela , Yilmazer Cengiz
Published: May 2022

Passive absorbers such as fibrous or porous materials are indispensable for high-frequency damping noises; still, problems are increasingly found at low frequencies. Resonant structures, such as membranes, Helmholtz resonators, and micro-perforated panels (MPPs), are usually used for treating the latter issues. These reactive structures are mass-spring systems with damping to absorb the system's resonant frequency, offering only narrowband absorption. For the sake of broadening the absorption bandwidth, a series of structures based on MPP networks in series and parallel have been explored to introduce multiple resonances. The current study examines the computational modeling of four parallel arranged transparent MPPs with different hole sizes, perforations, and back cavities. A prototype of this absorber is machined by laser and CNC techniques and tested in an impedance tube. The experimental data obtained from using the transfer function are in good agreement with the absorption performance calculated by the electro-acoustic equivalent circuit model (ECM). Results show a wider half absorption bandwidth of the overall system for more than 3 octaves (from 160 Hz to 1120 Hz). The initial findings enhance the possibility of designing single-layer absorbers that are wideband, tunable, and free from porous/fibrous materials.
Characterization of microbubble-enhanced molecular delivery to cells in acoustofluidic channels
Authors: Kopechek Jonathan A.
Published: May 2022

Cell therapies are rapidly emerging as a promising approach for treatment of many diseases, such as cancer and cardiovascular diseases. Non-viral methods for molecular delivery are currently in development to increase safety and reduce varability during manufacturing of cell therapies. Ultrasound-mediated microbubble cavitation has been utilized as an effective approach for non-viral molecular delivery via sonoporation or other mechanisms. However, prior ultrasound studies have primarily utilized static sample chambers, which have limited throughput and are generally not practical for cell therapy manufacturing processes. To address these limitations, we are developing novel acoustofluidic platforms to enable intracellular delivery of biomolecules as cells continuously pass through an ultrasound field in a flow chamber. We have investigated a range of fundamental parameters that influence acoustofluidic-mediated molecular delivery to human cells, including microbubble properties, channel geometry, and ultrasound parameters. In addition, we investigated biological factors that influence acoustofluidic-mediated molecular delivery to cells, including cellular properties and extracellular metabolite levels. The results of these studies will be presented to provide new insights into the key parameters and mechanisms that affect the efficiency of molecular delivery to human cells in acoustofluidic channels. Further development of acoustofluidic platforms may enable improved processes for manufacturing of cell therapies.
A numerical approach to estimate bulk wave speeds and dispersion
Authors: Allen Matthew S. , Blank Jonathan , Arrant Lesley , Roth Josh , Thelen Darryl
Published: May 2022

In many applications, one is interested in estimating the wave speed in materials or structures for which the wave equation cannot be solved analytically. This work is concerned with studying wave propagation in tendons and ligaments, where material anisotropy, nonlinearity, prestress, and non-ideal boundary conditions make an analytical solution impractical. In these cases, the finite element method can be used to simulate the structure in time and then extract wave motion, but this is computationally expensive, both in the simulation and for post processing. This work exploits the duality between modes of vibration and traveling waves to show how one can perform a semi-analytical dispersion analysis. The proposed method is then applied to models of tendons and ligaments of varying complexity and is found to provide significant insights into the nature of wave propagation and the expected dispersion behavior.
Enhancing low frequency sound radiation of electrodynamic loudspeakers with acoustic metamaterials
Authors: Peng Xiuyuan , Li Junfei , Cummer Steven
Published: May 2022

Since the radiation resistance of a vibrating membrane in the air is proportional to frequency in the subwavelength range, low frequency (<100Hz) sound radiating devices generally require a large vibrating diaphragm and a bulky enclosure to be efficient and loud enough for practical use. The tapped horn topology, where the front radiation of an electrodynamic driver adds up with the back radiation after propagating through the internal volume of a speaker box, has been widely used in custom audio to provide low-frequency enhancement to the bass unit. Recently, people have demonstrated the application of acoustic metamaterials based on multiple Helmholtz resonators (HRs) in sound absorption, sound insulation, directivity control, impedance matching, etc. In this presentation, we show that by branching the sound path of a tapped horn speaker box with multiple Helmholtz resonators and fine-tuning the geometry of each individual element, we can produce high and relatively constant sound pressure levels at sub-wavelength frequencies, making our methodology a good candidate for compact subwoofer design. Genetic algorithm (GA) is used to bring forth optimal performance within the geometric framework. Both transfer matrix method and numerical simulation are employed to derive the sound output of a particular subwoofer.
Design of multi-material sound transmission blocker using additive manufacturing
Authors: Maroo Trigun , Wright Andrew
Published: May 2022

Additive manufacturing is most commonly done through 3D printing, which can print in multiple materials. This enables the design and construction of new structures that can block sound transmission, such as a periodic array of TPU plastic cylinders embedded in a matrix of PLA plastic. The difference in wave speed between the plastics can cause reflections and interference inside the material. However, printing in multimaterials provides distinct challenges for the current 3D printing technology. When printing with multiple nozzles, the inactive nozzle can clog, and getting the two materials to fuse can yield warping and separation. We addressed these problems to fabricate a sample of TPU cylinders (1.8 cm diameter, 8.6 cm height) embedded in PLA (20 cm × 10 cm × 2 cm) and measured the change in STL relative to a block of PLA. We discovered an improved attenuation of about 5.5 dB at 6300 Hz.