bluuebunny/crossref_metadata_2025 huggingface dataset:
Infrasound generated by meteorological fronts: Observations and modeling
Authors: Chunchuzov Igor P. , Kulichkov Sergey , Popov Oleg , Perepelkin Vitaly
Published: May 2022

The results of study of the parameters of infrasound waves (amplitudes, coherences, grazing angles, azimuths, and horizontal phase speeds) detected during a passage of warm and cold fronts through the networks of microbarometers in Moscow region are presented. The observed effect of internal gravity waves on the coherence and phase speed of infrasound from meteorological fronts is analyzed. The differences found in the time dependences of the parameters of infrasound from warm and cold fronts that must be taken into account when detecting infrasound precursors of atmospheric storms are discussed. A possible mechanism for the generation of infrasound by the turbulent airstream flowing around the geometric irregularities of the meteorological front is proposed. [This work was supported by the Russian Science Foundation, Grant No. 21-17-00021.]
Signal versus noise: Propagation modeling applied to the detection of the tornadoes produced in Northern Alabama during the passage of a storm front in March, 2018
Authors: Waxler Roger M. , Frazier Garth , Hetzer Claus
Published: May 2022

On March 19, 2018, a storm front that produced at least eight confirmed tornadoes passed across northern Alabama. During that period, we had a network of infrasound arrays deployed throughout the region. Infrasonic signals were detected from each of the confirmed tornadoes; however, detections were not made on all of the arrays simultaneously. To understand why certain tornadoes were, or were not, detected on a given array, an infrasound signal propagation analysis was undertaken. A parabolic equation (PE) propagation algorithm was employed with atmospheric temperature and wind profiles input from the weather research and forecasting (WRF) model. To complement the propagation studies, a signal verses noise analysis was performed for each array. Taking the noise analysis into account, the correlation between detection versus non-detection and the predictions of the propagation model was quite good.
Spectral processing deficits appear to underlie developmental language disorders
Authors: Nittrouer Susan , Lowenstein Joanna , Tellez Kayla , O'Hara Priscilla , Sinex Donal
Published: May 2022

More than 50 years of research has suggested something is awry in the auditory functioning of children with language disorders, yet there remains no consensus on exactly what the problem is. To address this gap in knowledge, we have proposed a model termed the Auditory Bases of Phonological Acquisition. This model is based on the language feature known as dual patterning, which describes two levels of structure: one consisting of meaningful words and how they can be combined and the other consisting of word-internal, meaningless units and how they can be combined. We hypothesized that acquisition of this second level—phonological structure—is most affected by deficits in auditory functions, especially those involving the spectral domain. To test this hypothesis, we assessed children with and without language disorders between 7 and 10 years old on their abilities to detect spectral and temporal modulation and to perform relevant language tasks. The largest group differences were found at younger ages for spectral modulation detection (SMD). SMD thresholds were also found to correlate most strongly with language measures, especially those based on phonological structure. Outcomes suggest that keen sensitivity to spectral structure in the speech signal is necessary for acquiring precise phonological representations.
The effect of masker type on the sensitivity of the digits in noise test for detecting hearing loss
Authors: Dirks Coral E. , Bernstein Joshua G. , Brungart Douglas S.
Published: May 2022

The Digits-in-Noise (DIN) test, a quick hearing-loss screening tool with high test-retest reliability and good sensitivity and specificity, can substitute for an audiogram when calibrated audiometry is unavailable. Traditionally, listeners hear three digits in speech-shaped noise, but other masker types might more effectively distinguish normal hearing thresholds (NHTs) from elevated hearing thresholds (EHTs). This study compared the ability of different energetic and informational maskers to detect low-frequency pure-tone averages >20 dB HL. First, DIN perception was adaptively measured (N = 1149 subjects) to determine the 80% correct speech-reception threshold (SRT80) for each of six masker types: female, male, and multi-gender multitalker babble; positive and negative Schroeder-phase complex tones; and speech-shaped noise. Then, for each masker type, a different group of subjects was tested at the corresponding SRT80. As expected, preliminary results suggest that a positive Schroeder-phase masker produces the greatest differences in DIN scores between NHTs and EHTs. Sensitivity and specificity rates for EHT detection for each masker, along with intersubject variability and order effects, will be explored. [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.]
Comparison of laboratory and clinical computational metrics of acoustic measures of hearing-aid processed speech
Authors: Lundberg Emily , Muralimanohar Ramesh , Kates James M. , Arehart Kathryn
Published: May 2022

Computational auditory metrics are used to characterize hearing-aid fittings in the laboratory and the clinic. The purpose of this study is to compare the speech intelligibility index (SII) as a clinical metric to the laboratory based SII and the hearing-aid speech perception index (HASPI) and hearing-aid speech quality index (HASQI) laboratory metrics. These comparisons are drawn from a comprehensive dataset of hearing-aid fittings for 120 hearing-aid recipients from a hospital-based audiology clinic. Hearing-aid devices are drawn from multiple manufacturers and multiple technology levels, and a total of nine hearing-aid devices are included. Acoustic recordings are made with the hearing-aids positioned on the KEMAR manikin and include multiple hearing-aid settings for each patient (manufacturer’s recommended fit, first fit by the audiologist, and the final fitting selected by the patient). Metric values are computed for each of the settings, and these metric comparisons highlight the advantages and challenges of each metric in characterizing hearing-aid signal processing. In addition, the results provide insight regarding hearing-aid fittings from the manufacturer’s fitting versus clinician/patient driven fittings. [Work supported by NIH R01 DC012289, NIH NRSA T32DC012280, and GN Hearing OCG6790B.]
A dynamic substructuring technique for coupling and decoupling structure-cavity systems
Authors: Schultz Ryan , Davis R. Benjamin
Published: May 2022

Flexible structures adjacent to acoustic cavities are commonly encountered. In some instances, coupling between the structure and cavity causes non-negligible changes to the system frequency response. Here, we describe the use of modern dynamic substructuring techniques in coupling and decoupling structure-cavity systems. As input, free-interface in vacuo natural frequencies and modes of the structure are used along with an uncoupled modal representation of the cavity. In the acoustic model, the fluid-structure interface is typically modeled as pressure release, though faster frequency convergence is possible by enriching the representation with rigid-wall modes. The subsystems are assembled in modal coordinates with continuity at the interface enforced via Lagrange multipliers. This approach circumvents the calculation of coupling coefficients, and results in real-valued system natural frequencies and modes; however, the approach presents challenges when large numbers of interface degrees of freedom are present. Attempts to overcome these challenges with interface reduction techniques are described. Finally, this research led to the derivation of a formula approximating the in vacuo natural frequencies of test structures that are well coupled to adjacent acoustic cavities. The formula was successfully applied to an air-filled cylindrical test structure for which the frequency response was confounded by structure-cavity coupling.
The use of piecewise linear regression to explore development of children's listening-in-noise ability
Authors: Newman Rochelle S. , Shroads Emily , Chatterjee Monita
Published: May 2022

To explore the development of speech-in-noise comprehension, we tested children 15–48 months in a preferential-looking paradigm; children saw two images and were told which to attend to (“Find the keys!”). The target voice was masked either by a 9-voice blend (primarily energetic masking) or a single talker (providing informational masking; IM). We used piecewise linear-mixed-effects modeling to identify phases of developmental growth and their corresponding changepoints. Based on 51 participants to date, performance in multitalker babble was best described by a linear model with gradual improvement over time, but the 1-voice-masker condition was well-fit by a combination of three phases: a period of rapid growth until 25.3 months, followed by a period of relative stagnation until 43.4 months, then a second growth period. Bonino et al. (2021) argued that substantial development in IM ability occurs prior to 30 months, which corresponds well with our first phase. The second growth period may represent an increase in the ability to integrate “acoustic glimpses”; prior studies found that 5-year-olds, but not 30-month-olds, can restore interrupted speech, and our elbow at 43 months fits with this timeline. This demonstrates the usefulness of piecewise linear-mixed-effects as an approach to studying development.
How do noise and face masks affect speech intelligibility for cochlear implanted children?
Authors: Puglisi Giuseppina E. , Di Iulio Michele , Bottalico Pasquale , Murgia Silvia , Consolino Patrizia , Spadola Bisetti Massimo , Pitta Giuseppe , Shtrepi Louena , Astolfi Arianna
Published: May 2022

Due to the recent pandemic event related to COVID-19, many countries are mandating the use of face masks to reduce the spread of the virus. Unfortunately, those masks can have a detrimental effect on speech communication, particularly for vulnerable listeners like children with hearing loss. This work investigates which type of face mask yields the highest level of speech intelligibility for children with cochlear implants. Fourteen children with cochlear implants aged 7–15 years have been involved, together with a control group of six normal-hearing children. Online speech intelligibility tests (simplified Italian matrix sentence test) were performed testing different masks at different signal to noise ratios. The listening difficulty was also evaluated on a 5-points scale. The results of this study showed which type of face masks are recommended to maximize intelligibility for children with cochlear implants.
An iterative approach for estimating the sound speed and attenuation constant of air in a standing wave tube
Authors: Mo Zhuang , Song Guochenhao , Kang Hou , Bolton J. S.
Published: May 2022

In the present work, an iterative method based on the four-microphone transfer matrix approach was developed for evaluating the sound speed and attenuation constant of air within a standing wave tube. In particular, when the air inside the standing wave tube is treated as the material under test, i.e., as if it were a sample of porous material, the transfer matrix approach can be used to identify the air’s acoustic properties. Note that the wavenumber within the tube is complex owing to the formation of a visco-thermal boundary layer on the inner circumference of the tube. Starting from an assumed prior knowledge of the air properties, an iterative method can be applied in the post-processing stage to estimate the complex wavenumber accurately. Experimental results presented here show that although the results are sensitive to ambient temperature, a formula previously proposed by Temkin matches closely with the measured sound speed and attenuation constant. Furthermore, it is shown that the Temkin prediction accurately represents the variation of sound speed with frequency, in contrast to the formula recommended in the ASTM E1050 standard, in which the sound speed is assumed to be independent of frequency.
Raising the bar for jack-up floating floors—Understanding laboratory test results and proposed future test methodologies
Authors: Wells Adam P.
Published: May 2022

The jack-up concrete floating floor has been a staple in the field of architectural acoustical design for decades. Compatible with both spring and elastomeric isolators, the jack-up concrete floating floor system is often specified when the highest level of airborne and structure-borne vibration isolation separation is desired, and assurance of a decoupled floor is needed. Recent laboratory testing for jack-up floating floors under various configurations has yielded interesting and perhaps unexpected results. This paper will review the results from laboratory testing and dissect which factors appear to influence the airborne and/or the structure-borne isolation performance. A preview of future testing will be discussed, including new testing methodologies to validate existing conclusions and identify the influence of additional factors that may influence the airborne and/or structure-borne isolation performance.
The OrganoPlate® as vessel-on-a-chip model to investigate increased microbubble-mediated vascular permeability
Authors: Meijlink Bram , Beekers Ines , Langeveld Simone A. G. , Bishard Kristina , van der Steen Antonius F. , de Jong Nico , Trietsch Sebastiaan J. , Kooiman Klazina
Published: May 2022

The vessel wall is an important barrier modulating drug delivery to the underlying diseased tissue. Oscillating microbubbles can be used to locally enhance vascular permeability and sonoporate cells. As the mechanism is not fully understood, our aim was to grow 3D human vessels-on-a-chip in the OrganoPlate® 40 and use this model to investigate the effect of αvβ3-targeted microbubble and different ultrasound pressures (2 MHz, 100–850 kPa peak negative pressure) and cycle lengths (10×10 or 10×1000 cycles) on vascular permeability and sonoporation. The vascular permeability of 122 microvessels in 14 different conditions was quantified by microscopy imaging using the leakage pattern of a 150 kDa FITC-dextran dye. Furthermore, sonoporation was assessed using propidium iodide (PI). Upon microbubble and ultrasound treatment, an increase in vascular permeability was observed. Higher pressures and longer cycle length treatment showed a significantly higher vascular permeability and significant increase in PI uptake compared to all control groups (sham, ultrasound only, microbubble only), suggesting a simultaneous increase in vascular permeability and sonoporation correlating with higher pressure and longer cycle insonifications. In conclusion, the vessel-on-chip model is a suitable model to investigate how insonification with different ultrasound settings affects the microbubble-mediated vascular permeability increase and sonoporation.
Predictions for the perturbed root mean square displacement of a vibrating structure using modal parameters
Authors: Kaminski Allison , McDaniel James
Published: May 2022

A harmonically vibrating structure is considered for this study and divided into segments. The objective of the proposed research is to use knowledge from the nominal structure to make predictions as to how the root mean squared (RMS) displacement of the structure will change when either the mass or stiffness of a segment is scaled. Typically, to calculate the value for the modified RMS displacement, a linear solve is required to determine the new displacement vector. Additionally, the Neumann series may be used. However, this approach requires computations of matrix-vector products, which may become expensive for larger Degrees of Freedom (DOF) systems. Here, a method is proposed to predict the RMS displacement for the modified system from scalar values of the nominal system. Since only scalar values from the nominal system are required, predictions for the perturbed system can be made cheaply. The proposed method is based on the modal displacement equation and the assumption that the system is forced near a natural frequency. This assumption is used in Rayleigh’s quotient to approximate the new natural frequency as a function of the approximated modal stiffness and mass. The limitations and accuracy will be explored. [Work supported by ONR Grant N00014-19-1-2100.]
Ocean acoustics in the rapidly changing Arctic ocean
Authors: Dzieciuch Matthew A.
Published: May 2022

The Arctic ocean is undergoing rapid climate change, in fact it is the most rapidly warming area of our planet. Underwater sound is a uniquely effective tool for Arctic monitoring, because it can be used under the ice where satellites are blind. The most striking change has been the reduction of summer ice cover, but recent acoustic experiments have started to gather evidence for other changes as well, such as the reduction of ice scattering from the loss of multiyear ice and the formation of subsurface ducted propagation in the Beaufort Sea. The ambient soundscape is also of great interest as human activity increases in the region and as biological activity responds. Due the strategic importance of the Arctic during the cold war, there is a history of experimental work in the area but this short talk will try to show a few recent examples.
A look back at the development of the steelpan and related instruments
Authors: Morrison Andrew C.
Published: May 2022

One of the most significant acoustic instruments developed in the 20th century was the Caribbean steelpan. The steelpan family originated from the islands of Trinidad and Tobago when the islands were a British colony. Because musical traditions on the island were heavily reliant on percussion, local musicians quickly adopted the new drum type. Other factors contributing to the development of the steelpan family include the oil drilling industry and the use of the islands as naval facilities leading up to the second world war. The steelpan has primarily always been tuned by hand by individual tuners, as attempts to mass-manufacture the instruments have largely failed. The most recent innovations in steelpan construction contributed to the development of the instrument known as the Hang, a hand-played instrument. The popularity and scarcity of the Hang have given rise to a new percussion instrument known as the handpan.
Influence of the stratopause wind and temperature stratification on the waveform of the infrasound signal from the August 4, 2020 beirut explosion
Authors: Chunchuzov Igor P. , Kulichkov Sergey , Popov Oleg , Perepelkin Vitaly
Published: May 2022

The waveform of the infrasound signal received at a distance of 2398 km (infrasound station IS48) from the epicenter of the powerful explosion in Beirut, which occurred on August 4, 2020, is analyzed and modeled by using ray trace and pseudo-differential parabolic equation (PDPE) methods. Given a high temporal variability of the effective sound speed in the stratopause predicted by the European ECMWF model, we assumed that within the stratopause layer the increase in effective sound speed with increasing height is very small, on the order of 1 m/s. We also took into account the fine-scale layered structure of wind velocity and temperature in the real atmosphere, which is not taken into account in the ECMWF model. Accounting for the scattering of infrasound by strongly anisotropic (layered) inhomogeneities of the effective sound speed by using the PDPE wave method allowed us to explain for the first time the appearance of “fast” stratospheric arrivals, their time durations, time period between successive arrivals (about 110 s) and the waveform of the entire observed signal. [This work was supported by the Russian Science Foundation, Grant No 21-17-00021.]
Sonic anemometry on a high altitude balloon
Authors: White Robert D. , Banfield Don
Published: May 2022

Recent results demonstrate the promise of sonic anemometry for accurate, three dimensional, high update relative wind measurements in high altitude (stratospheric) balloons and for planetary science missions on Mars, Venus, and other environments [Banfield, JASA (2016); White, ASA (2020); White, AIAA (2020)]. The Tufts sonic anemometer, operating at 40kHz with six commercial piezoelectric transducers and custom electronics and frame, flew out of Fort Sumner, New Mexico on August 30 2021, reaching a height of 106°000 feet at float. The entire duration of the flight was 4 h and 42 min, with 2 h at float. The three axis sonic anemometry system collected sound speed and three dimensional relative wind velocity in two modes, at 3.4 Samples/sec or 1.5 Samples/sec. Results reported include comparison to balloon inertial and GPS motion to attempt to establish accuracy. Analysis is ongoing. [Work supported by NASA-NNX16AJ24G and NASA-80NSSC20M0007. Thanks to Chris Yoder and NASA Wallops Balloon Programs Office for technical support.]
Masked speech recognition in school-age children with Down syndrome
Authors: Leibold Lori , Porter Heather , Buss Emily
Published: May 2022

Masked speech recognition is poorer for children who are typically developing compared to adults, particularly when the masker is two-talker speech. Audibility, receptive vocabulary size, and executive function contribute to these age effects, all areas of weakness for children with Down syndrome. This study sought to determine whether these weaknesses put children with Down syndrome (n = 15, 5–17 yrs) at a disadvantage when listening to masked speech compared to age-matched children who are typically developing. Speech-in-noise and speech-in-speech was assessed using an adaptive, forced-choice procedure with a picture-pointing response. Audiological testing and standardized assessments of receptive vocabulary, non-verbal cognition, and executive function were also completed. Overall, children with Down syndrome performed more poorly than their typically developing peers. While the relationship between age and SRTs differs between the noise and speech maskers for children who are typically developing, this interaction was not observed for children with Down syndrome. Controlling for age, SRTs for children with Down syndrome were associated with vocabulary and executive function scores with the noise masker but not the speech masker. Results suggest that masked speech recognition is more challenging and is limited by different factors for children with Down syndrome compared to those who are typically developing.
Time reversal focal amplitudes as the focal position approaches boundaries
Authors: Clift Jay M. , Patchett Brian D. , Kingsley Adam D. , Barnes Lucas A. , Townsend McKayla , Anderson Brian E.
Published: May 2022

Time reversal (TR) is a signal processing technique that may be used to generate a focusing of waves at selected positions in reverberant environments. This study looks at the increase in the focal amplitude as the distance between the focal location and a boundary is decreased. Previous studies with audible sound in rooms have shown experimentally and numerically that there is a 3 dB increase in focal amplitude if the focal location is positioned 1 cm away from a wall; the numerical model used was a modal summation simulation. It has since been found that using an image source model simulation does not show any increase in focal amplitude as the focal location approaches boundaries. Experiments conducted in solid media with ultrasound showed that focal amplitudes increase by 6 dB at a free boundary. Experiments and modal summation modeling conducted with audible sound in a reverberation chamber also yielded similar results as the focal location reached the wall. The presentation will discuss why the image source model does not yield these results.
Extended imaging applications
Authors: Zartman David J.
Published: May 2022

Going back to the very basics of imaging techniques, all imaging requires a source, a target, and a receiver. Modern technology has expanded these capabilities in ways that might not be expected. A few basic principles still apply though. Taking a measurement affects the system is a well-known concept illustrated by the life or death of Heisenburg’s cat. Tom Clancy’s executive orders also defines a way to trace information pathways by using unique enticing differentiability. In 2015, OPM was hacked twice, compromising assumedly everyone’s information—is there thus a way to determine who is now intimately familiar with all of our information that wasn’t previously? If everything is compromised, are there ways to defend privacy anyway and compromise those believed to be incognito while compromising others? How does this apply to acoustics? A person practices a speech by themselves in an empty room. They are determined to be crazy talking to themselves by the person monitoring the room discreetly onsite. Then the person practicing a speech gets a critique of their speech by someone discreetly monitoring offsite unknown to the onsite personnel. Knowledge of the actual audience, both as the source speaking, and the receiver in the audience, is impactful.
Rapid soundcape generate using energy flux modeling
Authors: Heaney Kevin D.
Published: May 2022

The impact of anthropocentric sound on the living marine environment has been a growing area of concern. Human induced sound sources include shipping, siesmic exploration, pile driving, US Navy sonars, and miscellaneous (rare) explosions. The most ubiquitous and least regulated sound source is shipping, which dominates the ocean soundscape for frequencies below 500 Hz in much of the worlds oceans. Modeling of the ocean soundscape has been conducted using adiabatic modes, the parabolic equation and ray-tracing. In this paper, we present the modeling of the ocean soundscape (shipping and wind) with an energy flux algorithm. This analytic approach is very efficient and can handle mildly range-dependent environments. The flux model is used to generate regional sound models. With the inclusion of horizontal and vertical angle information at the model source position, this model can generate the noise directionality efficiently and can be then use for the performance of any particular array against directional noise in the ocean environment.
Exploring surface source distributions for ocean ambient noise interferometry with airgun shots
Authors: Ragland John , Abadi Shima
Published: May 2022

Ambient noise interferometry utilizes the cross-correlations of ambient sound to estimate the time domain Green’s function (TDGF). We have previously shown that ambient noise interferometry can resolve multi-path arrivals between two bottom-mounted hydrophones separated by 3.2 km, at a depth of 1500 m, and located 470 km off the Oregon coast. In 2019, a seismic reflection survey was conducted directly over the two hydrophones for 28 days covering a 763 km2 area. The airgun shots occurred every 37.5 m while the ship moved at a speed of ∼4.5 knots, equivalent to a shooting interval of 16 s. The hydrophone recordings during this survey provide the unique opportunity to understand the effects of the surface source distribution on the noise cross correlation function (NCCF). In this talk, we show the sensitivity of the NCCF to the surface source locations using simulated and experimental data. Then, we use the image source method to analytically define the location of the sound sources that contribute to different delay times in the NCCF. [Work supported by ONR.]
Underwater sound characteristics from down-the-hole pile drilling for a coastal construction activity
Authors: Guan Shane , Brookens Tiffini , Miner Robert
Published: May 2022

Sound generated by pile installation using a down-the-hole (DTH) hammer is not well documented and differs in character from sound generated using conventional impact or vibratory hammers. This study describes underwater acoustic characteristics from DTH pile drilling during the installation of 0.84-m shafts within 1.22-m steel piles associated with a cruise ship terminal construction in Ward Cove, Alaska. The median single-strike sound exposure levels measured at 10 m were 138 and 142 dB re 1 μPa2s for each of the two piles, with cumulative sound exposure levels of 188 and 193 dB re 1 μPa2s at 10 m, respectively. The sound levels measured in this study were significantly lower than previous measurements of DTH pile driving, and the sound is determined to be less impulsive in this study as compared previous studies. These differences likely result from fact that the DTH hammer used at Wade Cove did not make direct contact with the pile, as had been the case in previous studies. Further research is needed to investigate DTH piling techniques and associated sound-generating mechanisms and to differentiate the various impulsive structures from anthropogenic underwater noise in general.
Analysis of underwater noise due to hurricanes in the northern Gulf of Mexico
Authors: Hiern Jamie D. , Leftwich Kendal , Ioup Juliette W.
Published: May 2022

The proposed study will use broadband deep-water ambient sound field information collected by stationary and mobile passive acoustic monitoring platforms during a hurricane passage in the northern Gulf of Mexico. EARS buoys will be used for stationary data collection and reconnaissance flights of Slocum gliders equipped with hydrophones for mobile collection. The goal is to use these data to reconstruct storm wind speed distributions and to quantify changes in the ocean environment during hurricanes and tropical storms. The majority of this research is the signal processing involved in analyzing the collected noise data. Signal processing techniques employed include Fourier transform frequency analysis, Wavelet transform signal analysis, Bayesian signal processing, and machine learning, all of which have been applied to similar acoustic data in the past. Machine learning techniques are used to compare and correlate analyses from both bottom-moored EARS and moving glider data. Comparisons of data from gliders and from stationary EARS buoys can be made with similar analyses of recorded stationary EARS buoy data from the same and nearby locations over several recent years, now with a focus on estimating wind speeds from acoustic noise analysis. [This material is based upon the work supported by the Office of the Under Secretary of Defense for Research and Engineering under Award No. FA9550-21-1-0215.]
The acoustical design of the Imig Music Building addition—An end user’s perspective and an acoustician’s perspective
Authors: Kahn David
Published: May 2022

The design of the Imig Music Building addition at the University of Colorado/Boulder, which started in 2017, culminated in a building opening in Spring 2021. The facility includes a dedicated recital hall, a large ensemble rehearsal room with flexibility to double as a recital hall, a choral rehearsal room, theatre rehearsal room, and dance rehearsal studio along with many music teaching studios, practice rooms, and other acoustically sensitive spaces to support the College of Music’s program. The footprint of the building addition was very limited, resulting in an unusually large number of acoustically critical horizontal and vertical adjacencies. Perspectives on the design process and the successful resulting building will be presented by the end user and the acoustician. One goal of this presentation is to help attendees understand how to translate end user goals into acoustic design criteria and communicate those criteria to the other design team members (architects, engineers, and other specialty consultants such as theatre consultants).
A space for teaching opera performance
Authors: Glosemeyer Petrone Robin , Pfeiffer Scott
Published: May 2022

Within an academic context, learning and practice of performance is as important as the performance itself. The Brockman Hall for Opera at Rice University’s Shepherd School of Music has been designed to wrap the vocal performer with an intimate and immediate response without sacrificing envelopment achieved though reverberant energy. The result is a stage that allows the vocalist to stretch their sound to meet each of the 600 audience members while honing their skills of articulation. Orchestra musicians’ training is expanded in a pit that can support a wide repertoire from the baroque to a grand opera of 70 musicians, providing a space that allows musicians hone their skills as they accompany voice on stage.
Harmonic generation in a shear wave beam with spatially varying polarization in transversely isotropic soft tissue
Authors: Cormack John M. , Hamilton Mark F.
Published: May 2022

Shear wave beams with spatially varying polarization are characterized here by stretching the medium in the plane perpendicular to the propagation direction. Such a beam is produced in a soft tissue by applying motion perpendicular to the source plane, as with a piston source, due to the quasi-incompressible nature of the medium. In the transversely isotropic (TI) soft tissue, such as muscle, this polarization causes extension and contraction in the fiber direction, resulting in nonlinear propagation effects that are unique to the TI tissue compared to propagation in an isotropic tissue [Cormack, J. Acoust. Soc. Am. 150, 2566 (2021)]. A KZ-type equation is presented that describes a special case of propagation of a shear wave beam with spatially varying polarization in the TI soft tissue, accounting for material anisotropy along with leading-order effects of nonlinearity and diffraction. Solutions for harmonic generation from a time-harmonic source are presented for focused and unfocused Gaussian-derivative distributions of transverse displacement in the source plane. Of practical interest is the longitudinal displacement in the shear wave field, which possesses a second-harmonic component on the axis that results from stretching in the fiber direction. This second harmonic, which is absent in isotropic tissues, may be measured using existing elastography techniques.
Acoustic and viscoelastic characterization of hydrogel scaffolds to optimize preparation parameters for tissue engineering applications
Authors: Anderson Megan S. , McCraw Marshall , Zhang Lijie Grace , Solares Santiago , Sarkar Kausik
Published: May 2022

Cell growth and differentiation rely upon both biochemical and mechanical cues. Though the focus has historically been biochemical, there is an increasing interest on the mechanical properties of scaffold materials within the field of tissue engineering. When the mechanical properties of a scaffold material more closely match with those of the intended native tissue, the functionality of the tissue scaffold is significantly enhanced. This study explores how an acoustic and viscoelastic characterization of a popular hydrogel, gelatin methacrylate (GelMA), can be used to inform the synthesis and fabrication parameters for a variety of tissue engineering applications. GelMA scaffolds exhibiting a range of mechanical properties were produced by varying the concentration of GelMA and by varying the curing time of the scaffolds. Pulse-echo ultrasound techniques were used to determine the sound speed and attenuation, revealing a significant dependence on the GelMA concentration. Compression tests were also performed, showing an increased stiffness with certain preparation parameters. Finally, atomic force microscopy experiments were used to obtain the storage and loss moduli of the hydrogels, revealing an increase in hydrogel stiffness at short time scales for both the GelMA concentration and curing time.
Imaging mechanisms of therapeutic ultrasound in human islets
Authors: Chen Andrew W. , Jeremic Aleksandar , Zderic Vesna
Published: May 2022

We have previously shown that therapeutic ultrasound (TUS) has a wide range of effects on rat pancreas cells. We aim to explore additional possible mechanisms of TUS on the pancreas in a more physiologically relevant human islet model with the goal of potential therapies for type-2 diabetes. Fluorescence microscopy was performed on live human islets with dyes that can label for intracellular calcium, sodium, and reactive oxygen species (ROS). During microscopy, TUS was applied at 800 kHz at 0.5 W/cm2 with a pulse repetition frequency of 0.166 Hz and a 16.6% duty cycle. The amount of insulin released from human islets as a result of TUS application was quantified with an enzyme-linked immunoassay (ELISA). Thus far, we have noticed a trend of increased intracellular sodium and ROS generation due to TUS application; however, the percent increase in ROS appears to be less than for intracellular sodium. Our initial ELISA results show that TUS does appear to increase insulin release from human islets (0.55 ± 0.90 μU/ml min) when compared to control (−0.14 ± 0.19 μU/ml min), however, not as much as with the high glucose application at 20 mM (2.47 ± 3.54 μU/ml min). Ongoing studies aim to better characterize TUS effects.
The effects of nominal absorption in bone on the extinction lengths for scattering, absorption, and overall attenuation
Authors: McCandless Brett A. , Muller Marie
Published: May 2022

In cortical bone, the effect of absorption in the solid matrix on ultrasound scattering and propagation is not well understood, and for absorption, it is not easily incorporated into simulations and is difficult to measure independently from scattering attenuation. In this study, finite-difference time-domain simulations were conducted in maps derived from scanning acoustic microscopy images of human femur cross-sections. These maps were modified by controlling pore density (fixed at 10 pores/mm2) and diameter distribution (ranging between 30 and 100 μm). Eight nominal absorption values, ranging from 0 to 100 dB/cm, were attributed to the solid matrix. Absorption in the pores was set to 0.01 dB/cm. Propagation of ultrasound pulses centered at 8 MHz was simulated in both backscattering and through-transmission configurations. The scattering, absorption, and overall attenuation extinction lengths were obtained. T-tests demonstrated that varying the absorption significantly impacts the extinction lengths for scattering, overall attenuation, and absorption. The differences in values for the scattering, attenuation, and absorption extinction lengths when absorption varied from 20 to 40 dB/cm are statistically significant (respective p-values: 9.1 × 10−14, 3.3 × 10−5, and 8.8 × 10−5). It was also demonstrated that attenuation due to scattering dominates overall attenuation at low-nominal absorption values, whereas the converse is true at higher absorption values.
How to better design a research project to assess effects of transportation noise on humans
Authors: Muehleisen Ralph T.
Published: May 2022

The United States Air Force recently funded a research project to review the recent literature on noise and begin an update of the International Bibliography on Noise (IBON). Subject Matter Experts (SMEs) reviewed the literature on a variety of topics including human annoyance, non-auditory health effects, sleep disturbance, speech interference, child learning, animal effects, structural effects, and underwater effects. Each SME reviewed abstracts of thousands of papers and read hundreds of papers. As a result, the SMEs were able to see a vast range of methods for assessing effects of noise. In some of the topic areas, SMEs found that the number of really well-done research studies was actually quite small. While some papers did a good job of measuring or modeling noise, most of them did a poor job of assessing noise effects. While some papers did a good job of measuring or estimating noise effects, most of those did a poor job of measuring or modeling noise. In this presentation, one of the SMEs will present his thoughts on how to design a research project to do both a good job assessing transportation generated noise AND the effects of that transportation noise on humans.
Long-term aircraft noise exposure and incident hypertension in National U. S. Cohort Studies
Authors: Peters Junenette L. , Nguyen Daniel D. , Grady Stephanie T. , Hart Jaime E. , Whitsel Eric A. , Stewart James D. , Levy Jonathan I.
Published: May 2022

Few cohort studies have examined relationships between aircraft noise and health, none in the United States. We evaluated associations between aircraft noise and incident hypertension in three national cohorts of women, the Nurses’ Health Studies (NHS/NHSII) and the Women’s Health Initiative (WHI). Noise levels around 90 airports for 1995–2015 (in 5-year intervals) were modeled using the Aviation Environmental Design Tool and assigned to participants’ geocoded addresses over time. Hypertension risks were estimated using time-varying Cox proportional-hazards models for day-night average sound level dichotomized at 45 and 55 decibels (dB), adjusting for fixed and time-varying covariates. Hypertension cases were 33,190, 28 256, 5299 over 0.7M,1.3M, and 0.09M person-years in NHS, NHSII, and WHI, respectively. In combined NHS/NHSII, we observed adjusted hazard ratios (HRs) of 1.03 (95% CI: 0.99, 1.07) for 45dB and 1.07 (95% CI: 0.98, 1.15) for 55 dB cut-points. In WHI, we observed preliminary HRs of 1.03 (0.94, 1.16) for 45 dB and 0.93 (0.83, 1.05) for 55 dB cut-points. Overall, in these cohorts, we did not find clear evidence of a positive association between aircraft noise exposure and hypertension.
Utilizing mobile devices to facilitate collection of correlated noise data and psychological and physical effects
Authors: Riegel Kimberly A. , Pulley Kaila , Lefkowitz Robert M.
Published: May 2022

Noise is a pervasive urban issue that effects cities all over the globe. Exposure to noise has been linked to both psychological and health effects including sleep disturbance, increase in cortisol levels, and psychological impacts. Determining the effects of noise on large communities can be challenging because getting accurate noise levels that directly correspond to physical and psychological feedback is difficult. This study developed a mobile device application that allows a participant to take a sound level measurement and provide some feedback about the perception of the noise as well as provide some basic health information. This crowd sources the collection of data so that the sound levels that are taken are also directly related to the psychological feedback given. Preliminary data and user feedback from the initial deployment of the application will be presented.
Relationship between noise perception, vocal fatigue, and work-related stress among health workers in a hospital in Bogotá, Colombia
Authors: Cantor-Cutiva Lady Catherine , Carrillo-Gonzalez Andrés
Published: May 2022

To characterize the relationship between noise perception, vocal fatigue, and work-related stress among health workers. Cross sectional with the participation of 79 participants. Data regarding noise levels, voice functioning, and stress were collected through validated questionaries. Generalized Linear Models (GLMs) were used to evaluate the associations between the study variables. Our results show that more than 60% of health workers reported that noise conditions were high (47% considered that it did not affect their job performance, and 22% reported that it did). Concerning vocal fatigue, on average, health workers scored 8.30 for factor 1, 2.52 for factor 2, and 5.09 for factor 3, which suggests that participants were not feeling their voices very tired (factor 1), but they have physical discomfort associated with voicing (factor 2) and experienced improvement of symptoms after recovery (factor 3). Regarding stress levels, around 80% of participating health workers reported very high or high stress levels (61% for very high and 18% for high). Health workers are exposed to noise levels that affect their communication and mental health. Health care facilities should strive to keep noise conditions at its lowest levels to keep healthy conditions for communication and mental health.
Sea state induced sound transmission loss of atmospheric broadband sources
Authors: Vecchiotti Andrea , Cobb Faith A. , Ryan Teresa J. , Vignola Joseph , Turo Diego
Published: May 2022

This work presents a numerical study conducted on atmospheric sound propagation over sea. In particular, it focuses on the sound pressure level prediction uncertainties induced by the water surface roughness. To quantify these uncertainties, the generalized terrain parabolic equation (GTPE) is used to model sound propagation above water surfaces at different seastates. Water roughness is pseudo-randomly generated using Pierson-Moskovitz ocean wave spectrum. Building on a previous result that has established a simple expression for predicting single frequency sound transmission loss as a function of sea state, this work extends the approach to broadband signal from 125 to 1000 Hz. This work presents relationships between fully developed sea states (up to sea state 4) and the uncertainties on sound pressure level predictions at distances up to 1000 m from the source. These relationships are presented for typical nocturnal thermal gradients and for different elevations from the water surface.
Binary volume acoustic holograms
Authors: Brown Michael , Cox Ben , Treeby Bradley
Published: May 2022

Acoustic holograms or phase conjugate acoustic lenses are a simple inexpensive method for forming complex acoustic fields. They are 3D printable phase plates that can map an incident field onto a pre-defined phase distribution such that it diffracts to form a desired field. These phase plates areanalogues of thin optical holograms with a thickness d ≅ λ the design wavelength. Another class of optical holograms are “thick” or “volume” holograms, composed of weak periodic variations in the refractive index, for which d ⪢ λ. These volume holograms are significantly more selective to the wavelength and direction of the incident field allowing for greater ability to multiplex patterns within a single hologram. In this work, we explore the generation of volume acoustic holograms using multi-material 3-D printing. First, we numerically assess the impact of sound speed contrast, absorption, and quantisation on efficiency. A greedy optimization approach is then introduced for the design of a volumetric hologram from a desired set of input/output fields. We then validate the approach experimentally using test samples printed on an Objet Connex 350. Several holograms are fabricated demonstrating both spatial and frequency multiplexing of different patterns in a single volume.
Impact of ground reflections on firearms noise exposure metrics
Authors: Smith Jacob R. , Sorrell Avery K. , Gee Kent L. , Rasband Reese D. , Campbell Steven C. , Wall Alan T.
Published: May 2022

Outdoor measurements of weapons noise exposure are influenced by ground reflections. This paper analyzes the reflections’ impact on A-weighted equivalent level (LAeq) for two measurement campaigns involving standing shooters and dozens of elevated microphones. Although it is only a marginally accurate model of a gunshot waveform, the modified Friedlander equation was used to model the direct and reflected muzzle blast waveforms over a perfectly reflective surface. The calculation of the reflection’s effect on LAeq indicates a 2–3 dB increase relative to the free-field contribution over a relatively large spatial range. Validation of this model for most locations where the measured direct and reflected waveforms was well separated yields acceptable agreement for LAeq (<1 dB). Some challenges with the model development and comparison are discussed. This study contributes to improved weapons training safety and may eventually suggest revisions to the military noise exposure standard, MIL-STD-1474E. [Work supported by Air Force Research Laboratory through Ball Aerospace Technology Corporation.]