bluuebunny/crossref_metadata_2025 huggingface dataset:
Threading the needle between acoustic performance and fabric tensile structures
Authors: Kanter Shane J. , Nelson Smid Jennifer , Giegold Carl P. , Schuette Dawn , Glosemeyer Petrone Robin , Springthorpe Chris
Published: May 2022

Fabric tensile structures are a common architectural response to the need for an outdoor performance venue because they provide a lightweight, durable shelter, capable of spanning large distances. Particular care is necessary when threading the needle between efficient structural form and functional acoustic performance. This paper will discuss the acoustic design considerations necessary to yield the best acoustic results when designing outdoor fabric tensile structures. Concepts such as geometry, materiality, and amplified audio will be explored through the story of a few project examples.
Acoustics improvements to an outdoor music venue in an urban setting: A case study
Authors: Gulsrud Tim
Published: May 2022

This paper presents a case study of acoustics improvements made to the Number 38 Social Hall located in Denver's RiNo Arts District. The venue includes an outdoor music stage which is close to adjacent residential buildings, resulting in concerns about noise impact on the residences. During the summer of 2021, improvements were made to the stage area to reduce these noise impacts. We will review the changes made to the construction of the stage area, discuss sound level measurements made both before and after the improvements, and comment on the overall acoustical results of the improvements.
Self-organization of human stem cells into spheroids in a multinode acoustic levitation
Authors: Hoyos Mauricio
Published: May 2022

We present an approach based on acoustic levitation to grow the cells without wall interactions in order to promote 3D cell architecture (spheroïd, organoïd). The 3D microenvironment is indeed closer to In Vivo physiological behavior. The suspended cells are moved toward the acoustic pressure nodes where they are trapped and maintained in acoustic levitation in perfectly straight monolayers reaching very quickly the classical confluency of the cells in 2D culture. Interestingly, by maintaining the monolayers of MSCs in culture over a 24-h period, the MSCs spontaneously self-organized from cell sheets to cell spheroids with a characteristic time of about 10 h. This approach of 3D cell culture is based on the use of the acoustic wave coupled with microfluidics. We designed a standing wave cavity to generate a large acoustic radiation force (ARF) with an optical access, which allows the characterization of the self-organization dynamics. This 3D cell culture method has been validated on MSCs over 24h experiments. The MSCs viability has been checked. Moreover, they show a higher differentiation capacity compared to standard 2D culture conditions. These results open the path to long-time cell culture in acoustic levitation of cell sheets or spheroids for any type of cells.
The effect of stiffness and impurities on bubble nucleation in polyacrylamide hydrogels
Authors: Rawnaque Ferdousi Sabera , Simon Julianna C.
Published: May 2022

Tissue mimicking hydrogels can help us understand how viscoelastic properties (stiffness, elastic modulus, etc.) of biological tissues impact bubble nucleation. Adding impurities to hydrogels introduces inhomogeneities and increases their similarity to biological tissues. In this study, we evaluated the effect of stiffness and impurities on bubble nucleation in polyacrylamide (PA) hydrogels. Bubble nuclei were evaluated in 17.5%, 20%, and 22.5% v/v PA hydrogels, after which 0.25% w/v cholesterol crystals (maximum dimension = 0.6 mm) were embedded in the gels (n = 3 each). A 1.5 MHz focused ultrasound transducer was used to induce cavitation using 10-ms pulses with pressures ranging up to p+ = 89 MPa, and p− = 26 MPa and −6 dB focal dimensions of 9.4 × 1.2 mm (p−). Image analysis from high-speed photography showed bubble nucleation increases with increasing peak negative pressure and decreasing hydrogel stiffness. Adding cholesterol crystals largely decreases the acoustic cavitation threshold from p− = 19 MPa for 17.5% v/v hydrogels with no added impurities to p− = 12 MPa for the same concentration hydrogel with added cholesterol crystals. This suggests that hydrophobic cholesterol crystals weaken the gel or trap bubble nuclei, thus lowering the cavitation threshold. Future work includes investigating bubble nuclei in rat hepatocytes. [Work supported by NSF CAREER 1943937 and PSU Riess Fellowship.]
Low-frequency acoustic monitoring in urban environments
Authors: McComas Sarah , Arrowsmith Stephen , Hayward Chris , Stump Brian , McKenna Mihan
Published: May 2022

Arrays of infrasound sensors are commonly deployed in quiet rural settings to monitor high energy/low-frequency sources at distances of hundreds to thousands of kilometers. Advancements in infrasound sensor technology allow for measurement across the acoustic spectrum from infrasound (< 20 Hz) to low end audible (< 1000 Hz). This supports a growing interest in using infrasound arrays to monitor low energy/higher frequency sources at local propagation distances (<100 km). Examples of these sources include vehicles (ground and air), small explosions, and infrastructure (e.g., bridges). Many of these sources are driven by anthropogenic activity. In order to successfully monitor them, arrays of sensors will need to be installed closer to the sources of interest, thereby requiring arrays to encroach on urban spaces. The design, deployment, and utilization of these arrays will face challenges, such as limited open ground for installation and source signals that need to be separated from a complex acoustic noise field to be observed. This presentation shares techniques for instrumenting the urban environment and characterizing the ambient acoustic fields in three different urban environments. [Permission to publish was granted by the Director, Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center.]
Acoustic characterization of the Costa Rican Non-Standard Trills
Authors: Cortes Kandler Mariana
Published: May 2022

This study characterizes the Costa Rican Spanish trill realizations acoustically, identifies the number of variants, and determines if they are acoustically distinguishable. Costa Rican trills typically lack vibration of the tongue tip and are thus categorized as ‘non-canonical’ compared to the normative rolled trill. Only impressionistic descriptions have been provided, posing challenges to comparisons across studies and dialects. Using Audacity, 18 speakers (9 female, M = 37.4) recorded their productions of 72 tokens containing the trill in word-initial/medial position and in stressed/unstressed syllables. The study was conducted remotely through Gorilla Experiment Builder. Duration, percentage of voicing and center of gravity were measured in PRAAT. Classification was based on visual inspection of the spectrograms and waveform, with the audio as a guide. ANOVAs were used to examine the distribution of the variants and their acoustic differences. Ten categories are characterized acoustically, the fricative being the most common variant. Stress made realizations longer but did not reach significance. Word-initially, fricatives and trills had a significantly higher percentage of devoicing, and while approximants and trills tended to be shorter in this position, fricatives had the opposite direction of effect. Fricatives also showed considerable variation in center of gravity (M = 2159.2 Hz, Range = 5622.3 Hz). This acoustic description of the non-standard variants serves as a parameter for future comparisons with other dialects.
Effect of nasendoscopy procedure on acoustic features of voice and speech
Authors: Oren Liran
Published: May 2022

Nasendoscopy procedure enables direct visualization of voice and speech anatomy. The procedure passes a flexible scope transnasally to observe velopharyngeal mechanism or the larynx during speech and phonation. This imaging technique is commonly used simultaneously with audio recordings. Studies have identified important statistically-significant relationships between imaging-based and acoustic measures related to voice and speech quality. However, the effect of the nasendoscopy procedure itself on specific acoustic features is rarely being considered. Nasendoscopy is likely to cause some speakers to deviate from their typical vocal function by inducing stress and tension during recordings. Furthermore, the flexible nasendoscope can also change the sound and airflow behavior inside the vocal tract. The current study attempts to quantify how nasendoscopy influences acoustic features using a physical model based on a child's vocal tractduring a sibilant sound. An electrolarynx was used to provide a constant sound source with the input airflow to the model. Audio recordings were captured while retracting the nasendoscope from the level of the hypopharynx. Results show that compared to the same data taken without nasendoscopy, the scope can change measures of signal-to-noise and cepstral-peak-prominence by 15% and 7%, respectively. The nasendoscope had a minimal effect (<3%) on the SPL measure.
Model validation for simulated synthetic aperture sonar time series data
Authors: Philtron Jason , Reinhardt Brian
Published: May 2022

Synthetic aperture sonar (SAS) systems have grown in popularity due to their ability to create high-resolution sonar imagery with a high area coverage rate. Researchers continue to find new uses for SAS data products. To support the development of new uses and algorithms, it is important to be able to accurately simulate SAS systems with synthetic time series data. This simulated data can be used for many purposes, including estimating system signal-to-noise ratio and performance in a variety of environments, testing signal processing algorithms, and training algorithms to recognize objects in SAS imagery. For these processing tasks to be successful, the simulator must accurately represent physical phenomena in the oceanic underwater environment, which can be extremely complex. This presentation will outline a process for validation and verification of a high-frequency SAS time series simulator, and discuss several useful tests for validating model fidelity. Two fundamental concepts will be explored in depth: the sonar equation and spatial coherence theory. The sonar equation is important because it accounts for correct implementation of multiple lower level models such as geometry, beam patterns, propagation, and seafloor scattering strength. Spatial coherence is important because it is relied on to form coherent imagery.
Optimization of a partition’s ASTC to reach speech privacy goals, including innovative construction administration methods
Authors: Schnitta Bonnie , Harkin Sean
Published: May 2022

In order to achieve speech privacy in a room, it must be accurately engineered from the partitions, such as the walls, to the door. The speech privacy specification results from calculations based on the partitions’ STC. It is referenced by most building codes that these partitions, when built outside of the controlled lab, have an ASTC that is 5 points lower than the STC. When the ASTC is more than 5 points lower, strict speech privacy requirements are not met. This presentation discusses flanking and acoustic leakage points which degrade the wall by more than 5 points. Methodologies for resolving these issues of flanking or acoustic leakage will be presented that help bring the ASTC close to the STC and thereby meet the goals for speech privacy. A further discussion of innovative methods of construction administration to achieve these goals will also be discussed
Preclinical and clinical evaluation of super-resolution ultrasound imaging
Authors: Kim Kang , Chen Qiyang , Tan Roderick
Published: May 2022

Super-resolution ultrasound (SRU) imaging is an emerging technology that can visualize microvessels with unprecedented high spatial resolution compared to conventional contrast enhanced ultrasound imaging methods. Microvascular rarefaction occurs in both acute kidney injury (AKI) and chronic kidney disease (CKD) and leads to progressive injury, but no technology currently exists for safe, noninvasive assessment of kidney microvessels. In a preclinical mouse SRU study, we utilized a high-frequency small animal transducer to demonstrate reduction in microvascular density and increase in vessel tortuosity in a model of AKI due to ischemia-reperfusion injury. To translate SRU into clinical applications on human subjects, a fast SRU algorithm was implemented on a clinical curved array transducer for a deeper imaging depth and a larger imaging field of view and applied on healthy and CKD human subjects under an approved IRB. SRU did demonstrate reduced vascular density and blood flow in CKD patients compared to controls. SRU is thereby a novel and promising diagnostic and prognostic tool for kidney disease. Some encouraging pilot data and technical limitations will be discussed.
Influence of the model parameters for the finite element simulation of bone conduction in the human head
Authors: Kersten Simon , Vorlaender Michael
Published: May 2022

Bone conduction (BC) describes the transmission of vibrations via osseous, cartilage, and soft tissue pathways that contribute to the hearing sensation. It is important, e.g., in the context of BC hearing aids as well as for the occlusion effect and one’s own voice perception when using hearing protection or hearing devices. Finite element (FE) simulations of BC allow to overcome practical and ethical limitations of measurements with real heads and help to gain insights into underlying mechanisms. However, FE models inevitably require substantial simplifications due to the assignment and definition of volumetric domains and corresponding materials. Additionally, the material parameters are often only known within certain ranges. In this presentation, an overview on FE models of human heads used for BC research is given, and similarities and differences are discussed. The influence of the FE-inherent simplifications and the challenges in determining the model parameters are illustrated by varying the geometry and the material properties of a simple ellipsoidal model. The variability of the model predictions is compared to simulation results obtained with more realistic geometries and to the inter-subject variability observed in measurements with real human heads reported in the literature.
Building information modeling (BIM) automation for architectural acoustics, mechanical noise calculation
Authors: Thede Josh , Boyts Nick , Teel Jeff , Butler Kevin , Bargas Elaina , Roth Adam
Published: May 2022

There are several established procedures and design tools for estimating the background sound levels from heating, ventilation and air-conditioning (HVAC) building systems. Building Information Modeling (BIM) is a process commonly used in architecture, engineering, and construction that uses data to generate digital representations of a building’s physical and functional characteristics. We will demonstrate a BIM-automated design tool which uses a Dynamo script and a Revit model duct layout to estimate HVAC noise levels in buildings. With just a few inputs in the model, the script calculates the sound attenuation of each duct element and receiver room sound correction to estimate the HVAC background sound level in any space or building type. Leveraging existing data through BIM automation can help create efficient, optimized designs and improve coordination between mechanical engineers, architects, and acoustical consultants to meet acoustical design criteria.
Monitoring industrial acoustics with distributed acoustic sensing
Authors: Chambers Derrick , Li Peiyao , Sethi Harpreet , Shragge Jeffery
Published: May 2022

True-phase distributed acoustic sensing (DAS), a technique which uses low-power laser pulses to monitor along-fiber strain in optical cable, has proven useful in many geophysical research areas, including down-hole monitoring in oil/gas extraction, near-surface characterization, detecting and locating regional and global earthquakes, urban monitoring. Most of the geophysical applications to date, however, have focused on recording elastic waves propagating through solid media. In this work, we explore the response of DAS for recording acoustic propagation in air, as a function of fiber type and configuration, over frequency bands useful for monitoring industrial environments. We also present methods of creating simple fiber-composite sensing units for improving sensitivity, and strategies for combining solid-earth and acoustic monitoring to create an effective seismoacoustic array with a single DAS interrogator.
The effect of acoustic environments on singers’ vocal behaviors and mental effort
Authors: Ishikawa Keiko , Coster Elisabeth , Murgia Silvia , BOTTALICO PASQUALE
Published: May 2022

Singers perform in various acoustic environments; however, how the environments affect their mental effort is poorly understood. This study virtually simulated acoustic environments to examine the effect of reverberation time on singers’ vocal behaviors and mental effort. Participants were five vocally healthy singers who completed a minimum of undergraduate-level training. For the virtual environments, the voice signal was digitally processed by adding reverberation using a real-time effect processor of the digital mixer. The processed sound was played back to the participant using open headphones. The average T30 was 1.13 s in Low T30 condition, 1.39 s in Medium T30 condition, and 1.90 s in High T30 condition. Participants sang the American national anthem and rated their perceived level of overall effort, mental effort, physical effort, frustration, and performance using a modified NASA-TLX scale for each acoustic condition. Pupillometry was also used to measure the mental effort during each task. Their voice recordings were acoustically analyzed for intensity, singing-power ratio, alpha ratio, pitch accuracy, and vibrato rate and extent. The presentation will discuss: (1) individual differences in the participants’ response to the reverberation time and (2) the degree of agreement between the subjective rating and physical measurement of mental effort.
Nanostructured TiO2 as a sonophotocatalytic cavitation agent for spatially controlled sonochemistry
Authors: Jonnalagadda Umesh S. , Qianwenhao Fan , Su Xiaoqian , Liu Wen , Kwan James
Published: May 2022

Sonochemistry has garnered interest in its ability to facilitate greener chemistry by minimizing the use of hazardous reagents and harsh reaction conditions commonly used in chemical synthesis. The operating principle for sonochemistry is inertial cavitation, whereby bubble collapse will induce water pyrolysis to generate radicals for use in chemical reactions. Unfortunately, this process is limited by the low efficiencies in converting electrical energy to cavitation energy for free radical generation. To remedy this, researchers have exploited phenomena, e.g., sonoluminescence, using heterogenous catalysts to increase the radical generation rate; however, the stochastic nature of cavitation requires prolonged periods of high intensity, continuous wave irradiation to generate sufficient reaction rates. To address these limitations, we nanostructured TiO2 to function as sonophotocatalytic cavitation agents (SCAs). Our SCAs demonstrate that sonoluminescence can more efficiently occur at the catalyst surface and at lower energies using pulsed ultrasound. We evaluated the functionality of our SCAs by benzyl alcohol oxidation to benzaldehyde, where we further modified the catalysts using AuPd nanoparticles to function as a co-catalyst for enhanced sonoreactivity. Our findings present the key design elements for developing an effective SCA, allowing future work to explore the versatility of SCAs for a wide range of chemical applications.
Synergistic effect between nanostructured catalysts and high-frequency ultrasound: Application in biomass conversion to specialty chemicals
Authors: Valange Sabine , Amaniampong Prince N. , De Oliveira Vigier Karine , Jerome Francois
Published: May 2022

Within the context of sustainable chemistry, sonochemistry is now emerging as an alternative unconventional technology in catalysis. While ultrasound-generated radicals can participate in chemical reactions, mastering the reaction selectivity of polyfunctional substrates remains an elusive task. To address this challenge, we designed nanostructured metal oxides with leaf-like morphologies (e.g., CuO) by sonochemical synthesis (20 kHz) and investigated their activity for controlling the selectivity of oxidation reactions under ultrasonic irradiation in aqueous solution. We demonstrated that colocalization of the cavitation event onto the CuO surface active sites enables the direct utilization of radicals generated by cavitation for chemo-selective chemical reactions. In particular, we provided evidence for an alternative reaction pathway in glucose selective oxidation through synergistic cavitation–catalyst interactions at 550 kHz. We showed that the unwanted H• radicals stemming from water sonolysis are trapped by the surface lattice oxygen of CuO, thereby increasing the coverage of •OH radicals on the catalyst surface, and steering the selective oxidation of glucose to glucuronic acid, a valuable chemical whose synthesis remains a formidable challenge in the field of catalysis. This work also highlights that the particle size of the sonocatalyst is a key parameter governing an optimal transfer of radicals from the cavitation bubbles to the catalyst surface.
A sensorimotor approach to disfluency adaptation in typically fluent adults
Authors: Loucks Torrey , Aalto Daniel
Published: May 2022

Delaying auditory feedback (DAF) during speech is a potent auditory perturbation that can interrupt and prolong syllables and words, even though these disfluencies rarely affect typical speakers under non-altered feedback (NAF). Adaptation or compensation to auditory perturbations has been shown in typical speakers through a gradual reduction in the amplitude of formant shift responses. However, despite considerable research on DAF, it is still not known whether typical speakers adapt to DAF. In this study, we tested whether a comparable form of adaptation occurs with DAF in typical speakers as shown by a reduction in altered feedback disfluencies (AFD) during repeated consecutive readings, after a pause between readings and to a novel reading. We then tested for carryover effects after a single DAF exposure. A significant decrease in AFD rate was observed in 38 speakers that was sustained after a pause and for a novel reading. The adaptation effect extended to articulation rate (syllables/sec) in that rate increased for all speakers across readings. Evidence for carryover effects was inconclusive. By showing that typical speakers can adapt to DAF, the findings support a sensorimotor approach to auditory perturbation adaptation achieved through motor practice.
Vocalic contrasts in Hnaring Lutuv
Authors: Bohnert Amanda , Berkson Kelly H.
Published: May 2022

Lutuv, sometimes called Lautu, is an under-documented Chin language from the Tibeto–Burman language family spoken in Chin State in Western Burma by approximately 15 000 people (Eberhard et al., 2021, citing 2005 data that do not account for current military violence and displacement). Lutuv is also spoken in diaspora communities worldwide, including by about 1000 people in the Chin refugee community of Indianapolis (community estimate). Ongoing fieldwork with the Hnaring variety has revealed that, compared to related languages, Lutuv has undergone radical syllable structure simplification and attendant vowel inventory expansion. In addition to the low vowel /a/ and mid vowels /e ə ɔ/, Lutuv contains six to ten high vowels. These tentatively include four diphthongal vowels (/ie yə uɔ Ɯə) as well as six monophthongs /i y ɨ ʉ Ɯ u/. We explore the distribution of the vowels via a combination of acoustic and comparative data in an effort to better understand the articulatory and featural specifications thereof, with special attention paid to the high vowels. If all of these monophthongs truly are high, it would represent a startlingly large and typologically uncommon high vowel inventory.
Production accuracy of word-initial consonants in Mandarin-speaking children with cochlear implants
Authors: Yang Jing , Wang Xianhui , Yu Jue , Xu Li
Published: May 2022

The purpose of this study was to assess the accuracy of consonant production of children with cochlear implants (CIs) judged by naïve adult listeners. A total of 57 Mandarin-speaking children (22 with normal hearing and 35 with CIs) were recruited to produce a list of Mandarin words composed of 17 word-initial obstruent consonants in three different vowel contexts. A total number of 2628 tokens were generated and were divided into 10 subsets. One hundred Mandarin-speaking naïve adult listeners were recruited to identify the consonant productions through Gorilla, the online research platform. Each listener was randomly assigned to one subset. For each child speaker, the consonant productions were judged by 7–12 adult listeners and an average accuracy rate was calculated across all listeners for each consonant. The results revealed that the children with CIs showed lower accuracies and different confusion patterns on their consonant productions than the normal hearing controls. In particular, they demonstrated higher accuracy for stops but had major problems with the fricatives and affricates involved in the alveolar—alveolopalatal—retroflex postalveolar three-way sibilant contrast. Of the three places of the sibilant contrast, they showed the greatest difficulties for the alveolar sounds.
Layered and gradient model parameterizations in geoacoustic inversion
Authors: Dosso Stan , Bonnel Julien
Published: May 2022

This paper considers the importance of model parameterization in geoacoustic inversion and uncertainty estimation, including quantitative approaches to model selection as well as potential limitations of the information content of acoustic data to determine the form of geoacoustic profiles, e.g., differentiating between layered and gradient structures. In particular, general parameterizations are considered based on trans-dimensional (trans-D) inversion, which represents profiles as an unknown number of uniform layers, and Bernstein polynomial (BP) inversion, which represents smooth gradients as polynomials of unknown order. These approaches are illustrated and compared for the inversion of high-order modal-dispersion data collected at the New England Mud Patch. It is shown that while the data constrain the sound-speed profile in the mud layer to reasonably high precision, the data cannot differentiate between trans-D layered or BP gradient representations. However, simpler (fixed) parameterizations, such as a homogeneous layer or linear gradient, can be ruled out based on the Bayesian information criterion. Furthermore, the prior choice of parameterization (layers or gradient) has implications on whether the sound-speed ratio at the water–sediment interface is estimated to be less or greater than one with high probability (an issue other acoustic datasets may share). [Work supported by the Office of Naval Research]
Acoustic comfort in pediatric noninvasive exam: A study of bedside renal sonography for children
Authors: Tang Yi-Hsuan , Chen Julie Chia-Ping , Tsaih Lucky S. , Wang Hsin-Hui , Lin Chien-Hung , Chen Hui-Lan
Published: May 2022

Pediatric renal sonography is a non-radiation exposure and non-invasive procedure to evaluate kidneys and urinary tract structures. It is frequently performed in clinics and wards. Although there is no physical discomfort during ultrasounds, children would still experience agitation or crying due to unfamiliarity with medical environment. To provide comfortable medical experience and improve the quality of healthcare, we design a renal sonography process integrated with acoustic components specific for children. Patients under 7 years old are divided into three groups, under the age of 1, 1–3, and above 3. Pre-recorded music with nursery rhymes and fairy tales is played. Two time points are designed to evaluate acoustic integrated effect, along with preparing phase or real time of sonography starting. Data are collected from three timeframes: before, during, and after the exam. Physiological data will include heart rate, respiratory rate, and O2 saturation. Emotional behavior, such as agitation, crying, and smiling, will be recorded. This study will establish specific acoustic components and suitable intervention timeframe for children of different age groups. By having acoustic comfort, we hope children will have good experiences during sonography exam. As a result, the quality of medical examination and children wellbeing can be achieved.
Acoustical measurements and user evaluations of three new and existing ICUs
Authors: Siebein Gary W. , Lorusso Lesa , Miller Jennifer , Vetterick Matthew , Jones Ian
Published: May 2022

Acoustical measurements were taken in three existing ICUs in a hospital. New ICUs were designed to address acoustical and other issues identified in the three existing ICUs. The results of acoustical measurements made in the new and existing spaces are compared to the results of surveys and focus group discussions with user groups including hospital staff, patients, and visitors. While sounds of individual acoustical events were similar in the new and existing ICUs, the overall sound levels and frequency of sounds decreased in the new ICUs compared to the existing ICUs. This is because the design of the new ICU removed the sounds of nurses speaking at the nurses’ station, medical equipment, and other operations from the patient areas in the new ICU. Overall, the new ICU had a quieter environment for patients, nurses, and visitors as indicated by the acoustical measurements, surveys, and focus group discussions.
In vivo assessment of pulmonary edema and fibrosis in rats using separation of single and multiple scattering contributions and quantitative ultrasound
Authors: Lye Theresa H. , Roshankhah Roshan , Turnbull Aidan , Blackwell John , Egan Thomas M. , Muller Marie , Mamou Jonathan
Published: May 2022

The application of spectral quantitative ultrasound (QUS) and envelope statistical methods to lung ultrasound is complicated due to the presence of multiple scattering (MS). In this study, the relationship between QUS assessment of lung disease and scattering regime was explored by applying QUS to lung ultrasound data, where the single scattering (SS) and MS components were separated. Data were acquired by a Verasonics Vantage ultrasound scanner from 15 healthy rats, 19 edematous rats, and 20 fibrotic rats. SS and MS components of the data were separated by a random matrix theory approach. Spectral QUS and envelope statistical parameters were then estimated from the SS and MS data separately. Initial results were obtained using the healthy and pulmonary edema data, where the extracted QUS parameters were correlated to the wet-to-dry (W/D) weight ratio, a gold standard measurement of edema. Several QUS parameters were significantly correlated to W/D ratio for both the SS and MS data, and the highest correlation coefficient was 0.53 using the SS data and 0.48 using the MS data. These results demonstrate the utility of QUS for assessing lung disease and provide further insight on the effects of SS and MS on spectral QUS and envelope statistical parameters.
Bubble-based propulsion of engineered particles for drug delivery and immunotherapy
Authors: Shields Wyatt , Goodwin Andrew , Ausec Taylor R. , Lee Jin G.
Published: May 2022

Biological barriers, such as mucus and cellular endothelia, obstruct the transport of drugs to diseased tissues. In this talk, I will highlight our recent work to overcome these barriers using engineering particles that undergo bubble-based propulsion in response to ultrasound. I will focus on two innovations. First, I will share our collaborative effort to synthesize hydrophobically modified mesoporous silica nanoparticles (MSNs) stabilized with phospholipids that entrap hydrophobic drugs. When insonated with high-intensity focused ultrasound, the MSNs undergo cavitation to rapidly propel through dense media and release drugs. Second, I will share our effort to fabricate microparticles with arbitrary three-dimensional shapes using two-photon lithography. These microparticles are capable of entrapping air bubbles of a defined size, leading to their efficient, frequency-dependent propulsion when stimulated by ultrasound. By modifying the surfaces of these particles, they can robustly attach to epithelial cell layers and release small molecule drugs for extended durations. By way of outlook, I will discuss how these technologies have potential to stimulate immune cells against tumor progression and to abate inflammation in auto-immune diseases.
An observational protocol to measure learning in a problem-based learning vibrations course
Authors: Wright Andrew , Nolen Amanda
Published: May 2022

We have incorporated problem-based learning into several courses in an undergraduate engineering curriculum, including dynamics and vibrations. Students' prior knowledge (both formal and informal) were assessed through concept inventories to determine what prior knowledge supported or impeded the acquisition of new content in these courses. A point-and-click classroom observation tool was developed and refined over the span of two consecutive academic semesters to capture the students' interactions as they engaged in authentic learning activities in engineering. We identified patterns of discourse and interactions among the students and instructor, and, in vibrations, we identified a gap in the curriculum from the pre-requisite course, differential equations. The concept inventories and revised observational protocol that we have developed will enable instructors to assess the quality of the prior knowledge that students bring into a course and to analyze the manner in which students and instructor engage around the course content. We are developing bridge curriculum to improve transference of the theoretical knowledge in differential equations and the applied skills in vibration. This project spans across the beginning of the COVID-19 pandemic and includes observations on the interventions (successful and unsuccessful) where we attempted to continue student learning through a disrupted environment.
Coastal buffer distances and secondary sonic booms
Authors: Sparrow Victor W.
Published: May 2022

This presentation describes how secondary sonic booms have influenced our understanding of appropriate coastal buffer distances for supersonic aircraft. The International Civil Aviation Organization issued its Circular 126 in 1975 after the completion of test flights for the supersonic aircraft Concorde but before it began routine operations. This guidance was to prepare everyone for Concorde’s introduction. Particularly Chapter 5 recommended that a supersonic aircraft over the ocean should slow down to subsonic speeds at least 45 nautical miles before reaching the coastline, providing a coastal buffer distance to keep the sonic boom off of land. However, when Concorde began regular transatlantic service, the phenomenon of secondary sonic booms was better appreciated. Air France and British Airways changed their operations to provide much larger coastal buffer distances on the order of 150 nautical miles. Increasing the coastal buffer distances was successful in enabling routine Concorde operations. Implications for the introduction of future civilian supersonic aircraft are described. [Work funded by the FAA through ASCENT Project 57. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the FAA.]
Born approximation of acoustic radiation force and torque
Authors: Jerome Thomas S. , Hamilton Mark F.
Published: May 2022

The Born approximation provides a simple method for calculating acoustic radiation force and torque on compressible objects of arbitrary shape, which may be inhomogeneous. The specific acoustic impedance throughout the object must not differ significantly from that of the background fluid. Also, the incident field must not be too similar to a progressive plane wave, because the approximation is associated with radiation forces due to time-averaged energy density gradients in the incident field. Comparisons with a complete theory for radiation force and torque exerted by standing plane waves on compressible spheroids, based on expansions of the incident and scattered fields in spheroidal wave functions, indicate that the Born approximation is accurate for impedance contrasts up to at least 30% and for spheroids with sizes on the order of a wavelength. This presentation will review the derivation, validation, and applications of the Born approximation. Closed-form solutions for spheres and finite cylinders are presented and for selected distributions of material inhomogeneity. Applications include acoustofluidic separation of biological targets, and acoustic forces on nonspherical objects near interfaces. The approximation also serves as a useful benchmark for other methods of calculation. [T.S.J. was supported by an ARL:UT McKinney Fellowship in Acoustics.]
Born approximation of acoustic radiation force used for acoustofluidic separation
Authors: Gokani Chirag A. , Jerome Thomas S. , Haberman Michael R. , Hamilton Mark F.
Published: May 2022

Acoustofluidic separation often involves biological targets with specific acoustic impedance similar to that of the host fluid, and with dimensions on the order of the acoustic wavelength. This parameter range, combined with the use of standing waves to separate the targets, lends itself to use of the Born approximation for calculating the acoustic radiation force. Considered here is the configuration analyzed by Peng et al. [J. Mech. Phys. Solids 145, 104134 (2020)], in which two intersecting plane waves radiated into the fluid by a standing surface acoustic wave exert a force on a eukaryotic cell modeled as a multilayered sphere. The angle of intersection is determined by the velocity of the surface wave and the sound speed in the fluid. The acoustic field in this case is a standing wave parallel to the substrate and a traveling wave perpendicular to the substrate. For all parameter values considered by Peng et al., including spheres several wavelengths in diameter, the Born approximation of the acoustic radiation force parallel to the substrate is in good agreement with a full theory based on spherical wave expansions of the incident and scattered fields. [C.A.G. and T.S.J. were supported by ARL:UT McKinney Fellowships in Acoustics.]
Susceptibility to signal distortion in older listeners with hearing loss
Authors: Rallapalli Varsha H. , Souza Pamela E. , Arehart Kathryn
Published: May 2022

Older adults show significant individual variability in hearing aid benefit. Our recent work has identified factors contributing to this individual variability including age, degree of hearing loss, and working memory. Specifically, older adults with greater hearing loss and poorer working memory are disadvantaged (poorer speech recognition) by signal distortions arising from adverse listening conditions and aggressive hearing aid signal processing settings. In this presentation, we focus on the range of signal distortions (quantified by a cepstral correlation metric) due to hearing aid signal processing such as amplitude compression, frequency lowering, and digital noise reduction, combined with different amounts and types of background noise. Across studies, we characterized individual susceptibility to signal distortions with a comprehensive set of conditions ranging from laboratory simulations to realistic listening conditions. Earlier studies considered omnidirectional settings and co-located speech and noise conditions, whereas recent work has focused on clinically realistic conditions such as wearable hearing aids, microphone directionality, and spatially-separated speech and multi-talker babble. We will discuss the clinical implications of these findings, particularly the impact on customizing hearing aid fittings to maximize benefit for older individuals. [Work is funded by NIDCD.]
Listening effort over time: Single-trial electrophysiological measures of listening effort in middle-aged adults
Authors: Hunter Cynthia
Published: May 2022

Listening effort refers to the use of working memory and/or attentional resources to understand speech. In the current study, it was hypothesized that electrophysiological measures of listening effort, specifically oscillatory power in the alpha (8–12 Hz) and theta (4–8 Hz) frequency bands, would be affected by signal-to-noise ratio (SNR), reflecting increased effort in more difficult listening conditions. Furthermore, changes in effort across trials were assessed as interactions with trial number. Although most studies of effects of aging on listening effort have compared young and older adults, impacts of aging on hearing and cognition begin in middle-age. Here, middle-aged adults (n = 11; age range = 37—65 years) with and without hearing loss listened to spoken sentences in a background of multi-talker babble at a range of SNRs relative to an individualized SNR corresponding to the speech recognition threshold. Each electrophysiological measure tracked with SNR, such that alpha power decreased for lower (poorer) SNRs, whereas theta power increased at lower SNRs. Notably, the linear effect of SNR on alpha power emerged only at later trials. Overall, results support use of these measures as neural markers of listening effort during speech perception in middle-aged adults but indicate that alpha power measures of listening effort may emerge gradually over an episode of listening, perhaps reflecting listening-related fatigue, in contrast to theta power effects, which may emerge more quickly.
Willis elastic metasurfaces for unidirectional manipulation of flexural waves
Authors: Stojanoska Katerina , Shen Chen
Published: May 2022

Exceptional points label the region of the parameter space of a system in which two or more eigenvalues of a non-Hermitian Hamiltonian and their associated eigenvectors coalesce and become degenerate. Owing to the rich physics and engineering potential, there has been a recent interest in developing such acoustic or elastic media that display exceptional points. In this work, we present the design of a non-Hermitian planar elastics metasurface exhibiting Willis coupling for the control of flexural waves. The metasurface contains a series of unit cells with asymmetrically loaded piezoelectric and metallic blocks. Loss is further added to the system by negative capacitance piezoelectric shunting, which leads to zero reflection from one side of the metasurface. Asymmetric reflection properties are achieved when approaching the exceptional point of the system. Numerical simulations show that the proposed metasurface can realize asymmetric modulation of flexural waves propagation on the beam, manifested by unidirectional focusing of the incident waves. The proposed elastic metasurface has a planar profile, and the amount of loss can be conveniently tuned by the shunted piezo, making it useful for the manipulation of flexural waves where asymmetric control is desired.
Energy harvesting using an acoustic metamaterial
Authors: Baz Amr M.
Published: May 2022

Acoustic energy is harvested using a piezoelectric-based metamaterial. The considered metamaterial harvester consists of a multi-cell array of acoustic cavities, which are provided with piezoelectric boundaries in a one-dimensional arrangement. Once impacted by an incident parasitic acoustical energy, these boundaries convert this acoustical energy into useful electrical energy. An ANSYS finite element model is developed to model the dynamics of the multi-field energy harvesting, predict the harnessed power, and optimize the performance of the piezoelectric-based metamaterial when coupled with an external load. The predictions of the ANSYS model are validated against the predictions of a lumped-parameter model of the harvester, which is based on the equivalent electrical analog of the harvester. Excellent agreement is observed between the predictions of ANSYS and the lumped-parameter models. The predictions of the models are validated experimentally using a prototype of the harvester consisting of five cells each of which is manufactured from acrylic cylinders provided with piezoelectric bimorphs This arrangement enables harnessing the energy by the two sides of the bimorph in order to maximize the extracted power of the harvester. The frequency characteristics of the output power of the harvester are determined in relation to the bandgap characteristics of the periodically structured metamaterial. The presented work lays down the foundation for two and three-dimensional metamaterial energy harvesters.
A qualitative approach to explore auditory and visual perception in a hospital environment
Authors: Yilmazer Semiha , Uğurlu Zeynep M.
Published: May 2022

This study aims to examine the effects of auditory and visual perception in a hospital environment to provide comfort for the patients. The research focused on the waiting area of an oncology polyclinic. The binaural audio recordings and 360° photographs were taken from three different locations on the site. Those locations differed from each other in their acoustic and visual settings. Regarding the hospital acoustic environment, sound sources are human activity-related and technology-based. The visual aspects show differences; the reception area has an indoor opening, the courtyard area has indoor and outdoor connections, and the corridor area has none of them. Voluntary oncology patients in three locations in the polyclinic were interviewed. The audio recordings were visualized through signal processing, and the photographs were analyzed through image processing in MATLAB in order to define acoustic and visual differences among the locations. LAeq measurements were taken within the interview hours and one-hour intervals from three areas. The conceptual framework created with semi-structured interviews showed how the acoustic and visual environments affect the patients’ perception. The framework revealed audio-visual interactions in the hospital environment with its existing condition and preferred condition by the patients and proposed the suggestions to a hospital environment.
Prefabricated partitions in a hospital clinic—Airborne sound isolation design and field measurements
Authors: Teel Jeff , Thede Josh , Butler Kevin , Bargas Elaina
Published: May 2022

We will discuss the benefits, challenges, and requirements from an acoustics case study using modular prefabricated walls in healthcare. A recent hospital expansion/renovation project successfully used multi-trade prefab construction extensively in administrative, outpatient, inpatient, and surgical suite prep/recovery areas. This session will cover the acoustic and technical issues related to prefab partitions encountered during design and construction and post-construction acoustics observations and noise isolation class measurements.