bluuebunny/crossref_metadata_2025 huggingface dataset:
Using distributed acoustic sensing for ocean ambient sound analysis
Authors: Ragland John , Douglass Alexander S. , Abadi Shima
Published: April 2023

Distributed acoustic sensing (DAS) is a technique that utilizes the back scattering in fiber optic cables to densely sample the strain rate in both space and time. This technique has been widely demonstrated as a powerful tool for seismic sensing, but the efficacy of submerged, under-sea cables for ocean acoustic sensing remains underexplored. The ocean observatories initiative (OOI) conducted a distributed acoustic sensing experiment in November of 2021, where two of the fiber optic cables continuously recorded the strain rate for four days. In this talk, the ambient sound field recorded by the OOI DAS experiment will be explored. A statistical comparison of hydrophone measurements and DAS measurements will be presented. Additionally, the possibility of using ocean ambient sound techniques, such as ambient noise interferometry will be explored and compared to hydrophone analysis. [Work supported by ONR.]
Development of binder-jetting based skull phantoms for transcranial ultrasound research
Authors: Shahed Kazi Safowan , Heo Hyeonu , Manogharan Guha , Jing Yun
Published: April 2023

Ultrasound imaging can be used in time sensitive and dynamic environments like trauma care due to its advantages, such as real-time, affordable, portable, noninvasive, and nonionizing. Despite these advantages, transcranial ultrasound is hindered for brain imaging by the severe phase aberration of the human skull. To study phase aberration, it is crucial to have a fundamental understanding of the relationship between the macro-/micro-structure of the skull and the speed of sound distribution in the skull. This is proven to be challenging with ex vivo skulls, because the properties of these skulls are not controllable. To address this issue, we used binder jetting (BJT) 3D printing, high fidelity additive manufacturing, to print skull phantoms using calcium hydroxyapatite (HA) powder because HA is one of the major constituent materials of the human bone. After printing phantoms, they were sintered to get to the final form. The phantoms were validated via ultrasound measurements.
Ultrasound enhanced ocular drug delivery
Authors: Zderic Vesna
Published: April 2023

Our objective has been to determine ultrasound parameters that can provide optimal delivery of different drugs into the eye via transcorneal and transscleral routes, study mechanisms of ultrasound action, and determine long-term safety of this approach. We showed previously that exposing cornea to therapeutic ultrasound can lead to up to 10 times more delivery of a drug-mimicking compound into the eye, with only minimal alterations in the corneal structure. Subsequently, we continued to work on drug delivery problems with clinical relevance, such as promoting delivery of antibiotics and steroids for treatment of eye inflammations. Our studies also included modeling of temperature increases in the eye during ultrasound application, effectiveness and safety of delivery of an anti-parasitic drug PHMB into the eye, and delivery of macromolecules such as Avastin via transscleral route for treatment of mascular degeneration. Our research work showed that ultrasound application can be effective and safe for delivery of drugs of different molecular sizes into the eye in vitro and in vivo. This work may eventually lead to development of an inexpensive, and non-invasive ultrasound method that can be applied in an outpatient clinic to allow targeted delivery of medications for treatment of different ocular diseases.
Initial findings from Space Launch System liftoff measurements
Authors: Cunningham Carson F. , Gee Kent L. , Hart Grant W. , Anderson Mark C. , Bassett Michael , Mathews Logan T. , Durrant Jeffrey T. , Moats Levi , Coyle Whitney L. , Kellison Makayle S. , Kuffskie Margaret
Published: April 2023

This presentation documents initial findings from far-field noise measurements at NASA’s Kennedy Space Center during liftoff of the Space Launch System’s Artemis I mission, which occurred on November 16, 2022. The vehicle— the most powerful ever successfully launched into orbit—consists of four liquid-fueled RS-25 engines and two five-segment, solid-fuel rocket boosters (SRBs). Because this was the first launch, the noise radiation characteristics of this vehicle were previously unknown. Overall sound pressure levels, waveform characteristics, and spectra are described at distances ranging from 1.5 to 8.4 km. The levels due to the SRBs’ ignition overpressure are particularly intense in the direction of the flame trench exit. The post-liftoff maximum one-third octave spectrum has a peak at 20 Hz, and maximum overall levels are greater than described in a pre-launch environmental assessment. These and other findings presently submitted to JASA Express Letters further understanding of super heavy-lift rocket acoustics.
Community-based noise measurements of the Artemis-I launch
Authors: Kellison Makayle S. , Coyle Whitney L. , Moore Thomas R. , Gee Kent L. , Hart Grant W. , Cunningham Carson F. , Bassett Michael S.
Published: April 2023

A group of students and professors from Rollins College, in collaboration with Brigham Young University's acoustics group, measured far-field noise from the Space Launch System’s Artemis I mission liftoff. This presentation outlines the data collection process and measurements at locations 10 to 40 miles from Launch Complex 39B at Kennedy Space Center (KSC) in Cape Canaveral, Florida. Preliminary analysis of these measurements from outside the perimeter of KSC, including overall sound pressure levels, waveform characteristics, and frequency spectra, will be discussed.
Artemis I launch noise spectra: Effects of variable weather profiles over short- and long-range propagation paths
Authors: Coyle Whitney L. , Kellison Makayle S. , Cunningham Carson F. , Gee Kent L. , Hart Grant W.
Published: April 2023

NASA’s Space Launch System (SLS) launched the Artemis I mission at 1:47 am local time on November 16, 2022. The timing of the night launch offered a multitude of interesting weather effects over the propagation paths to measurement locations ranging from 1.5 km to 60 km. This presentation discusses spectra at different distances from Launch Complex 39B, both inside and outside the Kennedy Space Center perimeter. Preliminary analysis of the SLS sound pressure levels and spectra suggests many propagation phenomena are at play. In addition to geometric spreading, atmospheric absorption, and nonlinear propagation, complex weather profiles and ground effects are discussed. Initial results of a single-frequency Greens-function parabolic equation model, with estimated weather profiles along the propagation paths, will be offered with approximate source and receiver height to compare levels at several locations.
Multi-resolution non-contact laser-sensing damage detection technique for composite laminates
Authors: Ambrozinski Lukasz , Spytek Jakub , Mrowka Jakub , Pieczonka Lukasz J.
Published: April 2023

Numerous ultrasonic (UT) modalities have been developed to perform inspections of engineered structures. However, increased precision often comes at the cost of longer inspection times. As an example, guided waves propagating in plate-like structures allow fast inspection of large areas due to their long propagation distances. Damage characterization accuracy is, however, limited in this case due to relatively large wavelengths. On the other hand, local inspection with high-frequency bulk waves provides much more accurate damage characterization thanks to shorter wavelengths. The drawback of local inspection is the long scanning time necessary for large components. Here, we discuss a two-step laser-interferometer-based non-contact approach for the inspection of carbon-fiber-reinforced structures. First, a full-field screening using guided waves is performed to determine the possible damage locations. The identified hot spots are further evaluated in the second step with a high-frequency bulk wave system. A piezoceramic exciter is used for the guided wave setup, while a pulsed laser excitation source is used in the bulk wave setup. The proposed approach minimizes sample preparation time and is completely non-intrusive. The feasibility of the proposed framework is demonstrated in a complex shape, thin-walled composite structure with multiple defects.
Why we talk about voices as we do
Authors: Kreiman Jody
Published: April 2023

The problem of how to characterize voice quality is an endless source of debate and frustration across disciplines. The richness of the vocabulary available to describe voice is overwhelming, but the density of the information conveyed by voice has led some scholars to conclude that language can never adequately specify what we hear. Others have argued that terminology derives from tradition and lacks an empirical basis, so that language-based scales are inadequate a priori. Finally, efforts to link terms to acoustic signal characteristics have had limited success. However, a reconsideration suggests that a few terms appear consistently across studies, disciplines, and eras. These terms align with dimensions that account for acoustic variance in voice across speakers, regardless of gender, language spoken, or the kind of speech sample, and correlate with physical size and arousal across many species. They, thus, may have an evolutionary basis. This suggests talk about voices rests on a bedrock of biology: We have evolved to perceive voices in terms of size/arousal, and these factors structure both voice acoustics and the language we use to describe voices. Such linkages could help integrate studies of physical signals and their meaning, producing a truly interdisciplinary approach to voice.
Investigating the neural basis of the iambic/trochaic law
Authors: Llanos Fernando , Stump Timothy , Crowhurst Megan
Published: April 2023

The iambic/trochaic law predicts that listeners perceive loud sounds as rhythmic group onsets. While this law provides a solid framework to investigate the perception of foot inventories across languages, its neural underpinnings are currently unknown. Here, we test the hypothesis that the segmentation of rhythmic speech patterns is driven by neural oscillations that entrain in frequency and phase to the onset of rhythmic groups and units. We recorded EEGs evoked with a sequence of “ba” and “ga” units with their intensity manipulated to be perceived as a series of “BA ga” or “GA ba” groupings. We also manipulated the duration of rhythmic groups and units to achieve a rate of 3 units and 1.5 groups per second. Participants (N = 12) were instructed to segment each sequence (“BA ga BA ga …” and “ba GA ba GA …”) multiple times while wearing an EEG cap with 32 scalpelectrodes. Individual EEG spectra exhibited group and unit peaks at 1.5 Hz and 3Hz, respectively (ps < 0.001). Additionally, individual EEGs entrained to each rhythmic group with a different phase (ps < 0.01). These results support the hypothesis that the segmentation of rhythmic speech patterns in the cortex is mediated by a temporal code driven by entrainment.
Direction of arrival estimation using two-dimensional microphone arrays
Authors: Garner Curtis L. , Blotter Jonathan D. , Sommerfeldt Scott D.
Published: April 2023

Many signal processing applications require knowledge of where sources are located relative to the receiver. In cases where the source locations are not known in advance, methods must be implemented to estimate the direction of arrival (DOA) of the incoming signals. This paper proposes a method for estimating the DOA of acoustic signals in real time using a two-dimensional array of microphones. While many existing methods focus solely on obtaining an accurate estimate of one or more sound sources, the proposed method aims to provide a more complete picture of the sound field measured by the microphone array. This method can be easily adapted to identify and track any number of independent sources without a significant increase in either complexity or computational expense, making it suitable for applications where very little about the sound field can be known in advance.
Super resolution focusing of complex sources above a two-dimensional array of resonators in a three-dimensional environment
Authors: Kingsley Adam D. , Basham Andrew , Anderson Brian E.
Published: April 2023

Time reversal focusing above an array of resonators creates subwavelength features when compared to waves in free space. Previous work has shown the ability to focus acoustic waves near the resonators with and without time reversal with an array placed coplanar with acoustic sources. In this work, a two-dimensional array of resonators is studied with a full three-dimensional aperture of waves in a reverberation chamber. The full impulse response is recorded (including reverberation), and the spatial inverse filter is used to produce a focus among the resonators. Additionally, complex images are produced by extending the spatial inverse filter to create focal images such as dipoles and quadrupoles. Although waves at oblique angles would be expected to degrade the focal quality, it is shown that complex focal images can still be achieved.
Spatial sigma-delta modulation for coarsely quantized linear, circular, and spherical arrays
Authors: Corey Ryan M. , Singer Andrew C.
Published: April 2023

Quantization noise shaping, also known as sigma-delta modulation, is widely used in analog-to-digital converters. Such converters oversample a signal in time, quantize it to one or a few bits of precision, and then use analog feedback to shape quantization noise outside the band of interest, producing a high-precision output. Similarly, if a sensor array is spatially oversampled so that its elements are much less than one-half wavelength apart, then quantization noise can be propagated between channels to shape its spatial distribution. A beamformer acts as a spatial filter, removing shaped quantization noise to produce a high-precision output even with coarsely quantized sensors. Spatial sigma-delta modulation has been explored primarily for radio-frequency applications using linear arrays. In this presentation, we apply spatial noise shaping to dense acoustic sensor arrays, including circular and spherical arrays. For immersive audio applications, we demonstrate how noise-shaping feedback can be used to push quantization noise into higher-order Ambisonic modes.
Investigation of surficial sediment acoustic, physical, and biological properties in the New England Mud Patch
Authors: Lee Kevin M. , Ballard Megan , McNeese Andrew R. , Venegas Gabriel R. , Chaytor Jason , Clemo W. Cyrus , Frey Madeline R. , Dorgan Kelly M. , Wilson Preston S.
Published: April 2023

Measurements of surficial sediment properties at five locations in the New England Mud Patch (NEMP) were conducted during a coring survey in April 2022. At each location the Acoustic-Multi-Corer (AMC) sampled the upper few decimeters of sediment near the water-seabed interface. The AMC inserted acoustic probes into the sediment to collect in situ measurements of compressional waves (30–140 kHz) and shear waves (0.8–1.2 kHz) at near ambient conditions, after which cores were collected from the inter-probe propagation paths for ex situ analysis of the sediment properties. Onboard the ship, the cores were scanned with a Core and Resonance Logger (CARL), which provided high-frequency sound speed and attenuation measurements (100–1000 kHz) along the lengths of the cores, as well as resonance-based measurements of sound speed at 12–16 kHz. A subset of cores was sieved for infauna onboard the vessel, and the remaining cores were later analyzed in an onshore laboratory for porosity, bulk density, mineral and organic matter composition, and grain size. The frequency dependence of the surficial sediment acoustic properties will be discussed in the context of the mud’s physical and biological properties as well as sediment acoustics models. [Work sponsored by ONR.]
Dr. Jeffrey A. Nystuen—A PAL to acoustical oceanography
Authors: Miksis-Olds Jennifer
Published: April 2023

Dr. Jeffrey A. Nystuen was a visionary, innovator, proud student of life-long science learning, and friend. Jeff pioneered the development of the Passive Aquatic Listener (PAL), which was initially the Acoustic Rain Gauge (ARG). The PAL is a low-noise, broadband (100 kHz sampling rate), low-duty cycle, underwater recorder that operates according to an onboard, adaptive sampling protocol. The PAL was one of the first autonomous passive acoustic recorders that could sample for a full year with a frequency range capable of recording dolphin echolocation signals. While originally designed to detect rainfall and estimate the rate of ocean precipitation, the PAL has been used to better understand marine mammal patterns and trends, wind and storms, anthropogenic activity, and sea ice dynamics. The versatility of the PAL has evolved throughout its use from a standalone, archival autonomous recorder to a compact system integrated into Argo floats. PALs have been deployed in the Arctic, Indian, Atlantic, and Pacific Oceans in addition to many regional seas, coastal waters, freshwater lakes, and springs! The vast number of interdisciplinary questions and collaborations centered around the PAL technology highlights Jeff’s creative thinking, which has left a strong legacy in the field of acoustic oceanography.
Detection and estimation of rainfall from broadband acoustic signals
Authors: Mallary C. , Berg C. J. , Buck John R. , Tandon Amit
Published: April 2023

Jeff Nystuen contributed major advances in our understanding of the physical acoustics of rain falling on the ocean, culminating in his pioneering work quantifying rainfall from the shape of the acoustic spectrum. Ma and Nystuen [JAOT (2005)] exploited Vagle’s wind spectrum to self-calibrate hydrophones for long deployments as acoustic rain gauges. Their algorithm predominantly relied on 3 narrowband frequencies to detect rainfall, and correlated the rainfall amount with the power spectral density (PSD) at 5kHz. Recent research at UMass Dartmouth built upon the foundational work of Nystuen, Ma and others to examine how much additional information can be gleaned from broadband acoustic spectra. These algorithms exploit Principal Component Analysis and Linear Discriminant Analysis for rainfall detection, coupled with Error-Correcting Output Codes (ECOC) for quantizing rainfall estimation. Testing on 5 months of 3-minute PSDs from a noisy cove found a detection probability of 78 ± 5% with a 1.1 ± 0.3% false alarm rate. Moreover, ECOC-based hourly rainfall estimates achieved 0.97 ± 0.01 correlation with rainfall measurements at a co-located meteorological station. This talk plans to present results from a recent 6 week coastal deployment in deeper water. [Work supported by ONR/UMassD MUST program]
Calcium influx via mechanosensitive piezo1 channels regulates ultrasound targeted microbubble cavitation-induced endothelial hyperpermeability
Authors: Paranjape Anurag N. , Chen Xucai , Villanueva Flordeliza S.
Published: April 2023

Ultrasound targeted microbubble cavitation (UTMC) enhances drug-delivery across the endothelial barrier, but the underlying molecular mechanisms require further investigation. Here we explore the role of mechanosensitive piezo1 channels in regulating UTMC-induced hyperpermeability. Human coronary artery endothelial cells on transwells showed that UTMC (1 MHz, 250 kPa, 10 cycles, 10 ms interval for 10 s) caused hyperpermeability, demonstrated by reduced transendothelial electrical resistance (TEER) (1.7-fold, p < 0.05) and increased dextran flux across the monolayer (twofold, p < 0.01 for 70 kDa dextran, 1.6-fold, p < 0.05 for 10 kDa dextran). UTMC enhanced the paracellular permeability as shown by transient increase in inter-endothelial gaps. Inhibition of Ca2+ influx using mechanosensitive channel inhibitor GsMTx4, or piezo1 siRNA abrogated UTMC-induced hyperpermeability. Reduction in Ca2+ influx diminished inter-endothelialgaps and stress-fiber formation, suggesting Ca2+ influx is required, at least in part, for UTMC-induced hyperpermeability. UTMC increased nitric oxide (NO) production and inhibition of endothelial NO synthase with L-NAME abrogated UTMC-induced hyperpermeability, indicating a role for NO. Immunostaining showed that UTMC caused reorganization of adherens-junction protein VE-cadherin from a linear to interrupted pattern, which is known to be associated with hyperpermeability. Further elucidation of these pathways will aid in clinical translation and optimization of UTMC for delivery of cell-impermeant drugs.
Promoting immunotherapy of cancer with focused ultrasound
Authors: Price Richard J.
Published: April 2023

Immunotherapy (ITx) has revolutionized cancer treatment. Nonetheless, for several indications, many patients do not respond to ITx due to poor immune cell infiltration and/or limited ITx penetration into solid tumors. Both thermally ablative (T) and mechanical (M) forms of focused ultrasound (FUS) may be capable of overcoming these challenges. For example, the pre-clinical application of T-FUS in combination with myeloreductive gemcitabine elicits immunological control of 4T1 breast tumors and metastases, results that inspired the Br54 clinical trial for early stage breast cancer patients at UVA. Meanwhile, our Br48 clinical trial, which combines αPD-1 ITx with T-FUS in Stage III/IV breast cancer patients, shows that the well-tolerated treatment yields reduced regulatory T cells and transcriptional alterations consistent with inflammasome activation, interferon gamma signaling and αβ T cell activation. Regarding M-FUS, in pre-clinical brain tumor studies, we have used ImmunoPET imaging to optimize the timing of ITx antibodies (i.e., αCD47) administration with M-FUS-mediated blood-tumor barrier opening. This readily translatable treatment controlled GL261 tumors and improved survival markedly over previous studies that required multi-fold more αCD47 administration to achieve an effect. Overall, our pre-clinical and clinical results support the use of both T-FUS and M-FUS in combination with ITx for multiple cancer indications.
Developing a taxonomy of soundscape design from real-world examples
Authors: Chen Xiaochao , Aletta Francesco , Moshona Cleopatra , Henze Helen , Mitchell Andrew , Oberman Tin , Tong Huan , Fiebig Andre , Kang Jian , Schulte-Fortkamp Brigitte
Published: April 2023

Over the past 20 years, there has been a significant increase in soundscape studies focusing on urban scenarios. Policymakers are increasingly attracted to the concept of soundscapes, as reflected in several documents issued by international agencies that advocate a more user-centred approach when considering the urban acoustic environment. Despite widespread interest in the concept of soundscape, a consensus and systematic review of soundscape design and interventions, as well as a summary of empirical evidence on the benefits of sound methods, are still lacking. The catalogue of soundscape interventions (CSI) project aims to provide a tool for data collection and communication on soundscape practice, with the long-term goal of compiling frequent/recurring soundscape strategies into a “design toolkit” and developing a “design brief” to facilitate communication between local authorities and soundscape consultants and researchers. A platform for collecting examples of soundscape intervention has been published online, and the project is currently in its second phase of populating the example database. When sufficient practices have been gathered, a taxonomy of soundscape design will be developed, which will eventually become a “design toolkit.” To ensure that all perspectives are represented, and the taxonomy is based on consensus, stakeholders will be consulted. If a significant increase in the number of soundscape practices is detected, the taxonomy may require revision.
Soundscape evaluation based on participatory design
Authors: Lu Yichun , LAU Siu-Kit
Published: April 2023

The traditional soundscape assessment method assesses people’s perception of a selected acoustic environment using questionnaires or interviews. However, fewer studies have been done to investigate other methods for methodological triangulation. This research aims to propose an interactive approach for soundscape assessment research based on participatory design and apply this method to study the relationship between audio-visual elements and soundscape perceptions in residential areas. The experiment was conducted in a virtual reality (VR) environment. Thirty-two participants were invited to interactively create the audio-visual environment, which they thought was the most eventful or vibrant in outdoor and indoor contexts. The result indicated that the descriptor “eventfulness” could be related to “vibrancy” since participants selected similar audio-visual elements for these two descriptors except for building and greenery. Moreover, participants preferred to model open visual environments and more greenery in vibrant scenes, while they preferred semi-closed buildings and less greenery in eventful scenes. Besides, the result revealed that people in the indoor context might be more sensitive to traffic sound than in the outdoor context. Those results were consistent with those of traditional assessment methods, which means this method may be applied for a methodological triangulation in soundscape evaluation.
Soundscape study to develop a new noise ordinance
Authors: Brooks Bennett M. , Mattos Tiago F.
Published: April 2023

A soundscape study was conducted to assist with the development of a new noise ordinance in the City of Delray Beach, Florida. Delray Beach has an active entertainment district, which is popular with tourists and locals. Integrated into the district and the surrounding area are recent residential and business developments. During the pandemic the entertainment district activity was reduced. Since 2021, the activity was resumed. With the intensified activity noise complaints to the City increased. The existing subjective noise ordinance was not effective. A soundscape study was conducted to determine the existing conditions, and to develop new data-driven, perception-based objective standards. The goals for the new ordinance were to create certainty for stakeholders, to balance the interests of businesses and residents, to manage expectations, and to ensure fairness and consistency in application. Long-term and short-term acoustical measurements were made, several public workshops and hearings were held and two soundwalks were conducted. The results of data collection are discussed. At the time of this writing, the draft of the new ordinance is in process, to be presented to the City Commission for consideration. The outcome of this effort will be presented.
A preliminary field experiment to predict soundscape perception based on the biophilia hypothesis paradigm
Authors: Yilmazer Semiha , Alimadhi Enkela
Published: April 2023

In a time when biophilic design is investigated mainly with the incorporation of greenery in indoor environments, this study seeks to investigate the relationship between biophilic quality and soundscape perception in oncology polyclinics with and without a garden in Ankara, Turkey. The study, which evolves in an actual environment, claims that the Biophilia Hypothesis paradigm can predict the soundscape perception. Therefore, it aims to examine the audio-visual interaction manifested in polyclinics and its effect on both soundscape perception and biophilic quality using the Biophilic Interior Design Index (BIDI) and soundscape analysis ISO/TS-12913-3 method A. For the objective characterization of the environment, both binaural audio recordings and photographs have been taken, whereas the BIDI has been back-translated by two bilingual experts. In line with the existing literature, the study’s preliminary result supports the tendency for polyclinics with a garden to score higher in biophilic quality, therefore soundscape perceptual affective quality is placed on the positive dimension of the circumplex model, whereas polyclinics without a garden score the opposite.
Control of guided modes propagating in unconsolidated granular layers : Combined effects of local resonators and nonlinear elasticity
Authors: Mora Pierric , Chekroun Mathieu , Tournat Vincent
Published: April 2023

In this talk, we analyze the attenuation, by a line of local resonators, of guided surface modes propagating in an unconsolidated granular layer. Local resonators are made of dense solid parts added to the granular layer, mobilizing the elasticity of the medium itself for the restoring force and their own mass for the inertia effects. In addition, their weight induces local elasticity changes thanks to the nonlinear elasticity of such unconsolidated granular layers. We show numerically and experimentally that the induced resonance and elasticity change are key ingredients in describing the observed transmission and reflection effects, including mode conversion, for the different guided modes observed. We demonstrate that all these ingredients can be rationally combined to enhance the shielding effect and could be used as strategies to control seismic waves on a larger scale.
Finding wave equations for sediment acoustic theories
Authors: Holm Sverre , Chandrasekaran Sri Nivas , Näsholm Sven Peter
Published: April 2023

The two main theories for wave propagation in sediments, the Extended Biot theory and the Viscous Grain Shearing (VGS) theory, have been formulated in terms of dispersion equations only. Some have considered the lack of a wave equation to be a weakness that may indicate lack of a physical basis for these theories. In the Biot theory, it is the frequency-dependent viscodynamic operator which models viscous boundary effects in pores that poses the problem. It can be formulated as a ratio of Bessel functions for circular pores and as a ratio of tanh-functions for a 2D parallel plane duct. There is no simple equivalent time domain operator for use in the wave equation. In both geometries, the factor may, however, be approximated well with (1 + icω)1/2, where c is a constant. This factor also appears in the Cole-Davidson dielectric theory for complex media. The equivalent time domain operator, the fractional pseudo-differential operator, enables the formulation of wave equations for all three wave modes. The same operator turns out to be central for transforming the dispersion relations of the VGS theory to time-space wave equations. These wave equations enable a closer study of properties of the medium models than that obtained from dispersion relations alone.
Combining granular aerogels with additively manufactured porous structures for broadband sound absorption
Authors: Nobles L. Paige , Xue Yutong , Bolton J. S. , Sharma Bhisham
Published: April 2023

Our recent investigation [1] showed that the absorption behavior of granular aerogel agglomerates with average particle diameters less than 50μm is dominated by periodically spaced, high absorption peaks and troughs. While the absorption peaks, especially at lower frequencies, are desirable from an engineering application perspective, overcoming the loss in high frequency performance remains a challenge. Furthermore, the practical application of granular aerogels is limited by the difficulty in handling them. In this work, we propose a new design for a broadband noise absorber achieved by layering the aerogel granules within a 3D printed porous network. The design provides a robust method of incorporating aerogels within noise reduction packages and can be tailored by altering the rigid porous network and the layering arrangement. In this presentation, we present our preliminary findings regarding the fabrication and testing of such hybrid sound absorbers. [1] Dasyam A, Xue Y, Bolton JS, Sharma B. Effect of particle size on sound absorption behavior of granular aerogel agglomerates. Journal of Non-Crystalline Solids. 2022 Dec 15;598:121942.
Elastic behavior of additively manufactured 316L stainless steel with changing laser power and speed
Authors: Hayward Mason , Starlard Kevin , Murray Erica , Petculescu Gabriela
Published: April 2023

Ultrasonic investigations of additively manufactured 316L stainless steel were performed to reveal correlations between properties and printing parameters. The laser power and scanning speed of the selective-Laser-Melting printing process were varied systematically: 40–100 W in 20-W steps, and 600 mm/s to 1200 mm/s in 200-mm/s steps. Resonant ultrasound spectroscopy and pulse-echo measurements were performed. The extensive data allow for observations of specific behaviors in the elastic properties of the material as a function of VED, the volumetric energy density (VED ∝ power/speed). An increase in the values of c11 and c44 with increasing VED is confirmed, followed by saturation in the expected complete-fusion zone. The saturation values are comparable to those of the wrought (∼250 GPa for c11 and ∼75 GPa for c44). At low VED, c11 is quite small (∼100 GPa). Furthermore, an interesting behavior appears in the incomplete-fusion zone. At a fixed VED, the laser power level affects the elastic properties. As power increases, the porosity decreases, the mass density increases, and both elastic constants increase. The details observed in the material’s elastic properties are important for its correct usage in space and biomechanical applications.
Damping in precision vibration control: A review
Authors: Ryaboy Vyacheslav M.
Published: April 2023

This paper reviews various damping techniques used in precision vibration control devices such as optical tables and other vibration-isolated platforms for sensitive optical, acoustical, and life sciences experiments, as well as advanced technological processes [1]. These techniques include tunable dynamic vibration absorbers, active damping, and modal damping in isolated platforms, as well as active and passive damping in vibration isolators. The theoretical background, principles of implementation, and test results are illustrated by case studies that include a large tuned-damped optical bench in a petawatt laser facility, multi-beam lithography enabled by active damping, effective damping of vibration-isolated workstation for experiments on animal hearing, and atomic force microscopy assisted by active vibration isolation. [1] V.M. Ryaboy, Vibration Control for Optomechanical Systems, World Scientific, 2022.
Localization with deep learning networks for super-resolution ultrasound imaging
Authors: Brown Katherine , Redfern Arthur D.
Published: April 2023

OBJECTIVE: The objective was to optimize an acquisition methodology and deep learning network to localize a microbubble (MB) contrast agent on a preclinical ultrasound (US) platform with the goal of moving super-resolution ultrasound (SRUS) imaging towards clinical adoption. METHODS: A deep learning network was optimized based on the latest advances in computer vision, convolutional neural networks, and transformer architectures. Synthetic data were produced in an US simulation of tissue with MB at various concentrations flowing in a vascular model. The network was programmed in PyTorch and trained on 12 000 synthetic images. US data were collected with a Vevo 3100 (FUJIFILM VisualSonics Inc) using an MX201 linear transducer. In vivo testing images were obtained from hepatocellular carcinoma (HCC) rat liver tumors. After MB injection (Definity), 3000 frames were collected at 90 Hz. RESULTS: The SRUS in vivo results reveal a high level of detail. The smallest vessel measured 34 μm in diameter. Compared to conventional methods, the network improved performance by 10x on a CPU. A GPU platform could give an additional boost, by as much 100x. CONCLUSIONS: Deep networks for localization show potential for improving performance of SR-US towards a real-time imaging modality. The use of a pre-clinical focused US platform demonstrates that localization can improve the visualization of vascular detail and aid clinical understanding.
Introducing sound speed variability in laboratory water tank
Authors: Hopps Alexandra M. , Neilsen Tracianne B. , Clift Jay M.
Published: April 2023

The variation of temperature in the ocean causes changes in sound propagation. To simulate the naturally occurring variability in an ocean environment, this project quantified the sound speed variation achievable in a laboratory water tank. The rectangular tank (1.2 m × 3.6 m with 0.5 m depth) has anechoic paneling that minimizes lateral reflections. In this experiment, temperature was measured from four different temperature sensors. The temperature was used to calculate the sound speed in the tank as a function of time while the water was cooled and heated. Sound speed values were compared from four different empirical equations. We found that while the temperature varies in time, the temperature is relatively uniform at different locations in the tank. In experiments involving three hours of heating and adding 100 pounds of ice, there was a 10-degree Celsius difference in temperature, corresponding to a 20 m/s difference in water sound speed. By adding an additional degree of variability to the tank measurements, a portion of the variability seen in the ocean can be replicated. This sound speed variability can then be used to test the robustness of machine learning algorithms.
Turbulence induced self-noise on cylinders in low velocity flow
Authors: Oba Roger , Ramamurti Ravi
Published: April 2023

Nominally stationary acoustic sensors, e.g., buoy suspended or bottom anchored, are subject to various environmental flows. These flows in turn generate turbulence along the surface of acoustic enclosures that give rise to self-noise. A continuous-flow water tunnel replicates at-sea flows for evaluation of acoustic enclosures for such self-noise. In preparation for the tunnel experiments, direct numerical simulations of hydrodynamic flow around the acoustic sensor housing have been performed, and show turbulence along the housing surface. Time-space analysis of pressure variation along the surface of the housing shows significant acoustic-like surface interaction at low frequencies, even at very low mean flow velocity. The broad frequency content of the turbulence is due to intermittently generated, irregular, coherent vortex structures that separate from the surface of the housing and advect downstream. These structures drive rapid surface pressure transients that propagate within the housing to the acoustic sensors as noise. The potential for noise reduction using foil shaped housing is explored. This research is supported by 6.2 NRL base program sponsored by the Office of Naval Research. Distribution Statement A: Approved for public release. Distribution unlimited.
Using audio content and emotional response to predict soundscape perception through machine learning
Authors: Acun Volkan , Yilmazer Semiha
Published: April 2023

This study is concerned with utilizing machine learning techniques for predicting soundscape perception by identifying the audio content of soundscapes and linking it with people's reported emotional responses. This research goal required developing an environmental sound classification model; however, the capabilities of these algorithms have some significant drawbacks. Supervised learning algorithms need a large number of labelled audio samples for each sound category. Given that a model for classifying environmental sound must be trained using a wide range of sound sources, this presents a substantial problem for developing a robust model that generalizes well to different environments. We prepared a convolutional neural network (CNN) based classifier; however, to tackle the limitations, we used musical instruments for the training dataset rather than environmental sound sources and optimized the neural network for this task. Based on how closely the soundscapes' audio content resembled the musical instruments in the dataset, CNN classified the soundscapes' audio content. We then conducted an online soundscape perception survey to evaluate participants' emotional responses to numerous soundscape clips. We prepared a feedforward neural network, which used the sound classification model's audio content output with the survey data to create a model for predicting people's responses to different soundscapes.
Quantitative biomechanics using reverberant optical coherence elastography
Authors: Larin Kirill
Published: April 2023

In this presentation, I will introduce and discuss recent developments in our effort for quantitative biomechanics of tissues and organs using a multifocal acoustic radiation force source (that combines an ultrasound transducer and a 3D-printed acoustic lens) in reverberant optical coherence elastography (Rev-OCE). An array of plano-concave acoustic lenses, each with an 11.8 mm aperture diameter, were used to spatially distribute the acoustic energy generated by a 1 MHz planar ultrasound transducer, producing multiple focal spots on a target plane. These focal spots generate reverberant shear wave fields detected by the Optical Coherence Tomography (OCT) system. The effectiveness of the multifocal Rev-OCE system in probing mechanical properties with high resolution is demonstrated in layered gelatin phantoms, tissues ex vivo, and whole mouse embryos in vivo.
Broadband pulses in shear wave elastography
Authors: Szabo Thomas L.
Published: April 2023

Usually pulses used for shear wave elastography and ARFI are considered to be monochromatic; however, there are advantages to using broadband pulses and including the absorption characteristics of the tissues. A new broadband formulation for volume acoustic radiation forces is presented that accounts for the pulse shape and the changes it encounters propagating through tissues with frequency power law absorption properties. This equation reduces to the well know formulation for the continuous wave case derived by W. Nyborg. Ideal tone bursts employed in elastography have the same time average intensity tissue as continuous wave intensities, irrespective of length. Tone bursts in viscous media have turn-on and turn-off transients called “precursors” and “postcursors,” which can increase pulse amplitudes at the ends of the pulses [Szabo, JASA 45(1): 124–130 (1969)]. By accounting for absorption across a broader bandwidth pulse spectrum, these transient effects can be reduced. Their effects and the potential for pulse shaping are discussed.
Improving group velocity based estimates of arterial stiffness
Authors: Capron Charles , Roy Tuhin , Guddati Murthy , Urban Matthew W.
Published: April 2023

Arterial stiffness is a predictor of cardiovascular diseases, the leading causes of death worldwide. Ultrasound-based methods that measure arterial wave propagation have promise for evaluating local stiffness in vivo. However, geometric properties of arteries cause dispersion, invalidating typical assumptions underlying the relationship between shear modulus G and group velocity cg, which clinical implementations of ultrasound shear wave elastography do not consider. Here, we examine the dependence of these estimates on geometry and evaluate alternative approaches. Wave motion in the proximal wall of an artery after application of focused acoustic radiation force is simulated with a semi-analytical finite element (SAFE) model, and cg is estimated using a time-to-peak algorithm to determine G with several methods. First, the value of G a clinical scanner would report is calculated assuming a bulk medium. Second, a pulse wave velocity (PWV)-based G estimate is calculated by taking cg = PWV and applying the Moens–Korteweg equation. Third, we develop an interpolation-based method to provide a corrected G estimate using data generated by the SAFE model. Simulation results show severe geometry-dependent bias with the bulk method, which is partially ameliorated with the PWV method and substantially improved with the interpolation approach. Results are validated using arterial phantoms.
A thermally polarized 129Xenon phantom for MR elastography studies in a ultra-high field MRI system
Authors: Canavesi Irene , Li Weiguo , Klatt Dieter , Royston Thomas
Published: April 2023

Being second only to cardiovascular problems, respiratory diseases account for five of the 30 most common causes of death worldwide. One way to address this problem is by improving early diagnostic methods. Due to the complex heterogeneous structure of the lung, conventional imaging and elastography techniques based on ultrasound and magnetic resonance (MR) imaging have been limited in their ability to provide regional detail of morphology and mechanical properties, both of which can be altered by respiratory diseases. Hyperpolarized 129Xe(non) MR imaging has shown promise as a means of regionally quantifying ventilation, microstructure, and gas exchange efficiency in the lung parenchymae. MR elastography of the lungs using hyperpolarized gases is also being explored. To advance development, a stable phantom for MR imaging and elastography calibration using 129Xe is needed. The design, fabrication, and experimental testing of a stable thermally polarized 129Xe MR imaging and elastography phantom for a 9.4 T preclinical MR imaging system are presented.
Soft tissue characterization by dynamic impact analysis: Results on agar-based phantoms
Authors: Poudrel Anne-Sophie , Bouffandeau Arthur , Rosi Giuseppe , Nguyen Vu-Hieu , Haiat Guillaume
Published: April 2023

The mechanical characterization of soft tissues is of great importance in different medical fields since a change of soft tissue properties may be of physio-pathologic nature. This study investigates the feasibility of using impact analysis to measure the mechanical properties of soft tissue mimicking phantoms made of agarose. The impact analysis is performed on agar-based specimens with various concentrations by applying small impacts on a beam in contact with the surface of the specimen. The time variation of the signal corresponding to the impact force is analyzed as a function of the agar concentration and the impact force amplitude. A temporal indicator τ is developed, corresponding to the time difference between the initial impact and the rebound of the beam on the hammer. The results show a decrease of τ when the agar concentration increases. The method appears to be sensitive to non-linear phenomena related to the material behavior and/or to contact phenomena between the beam and the specimen. The error on the estimation of the percentage of agar is of the same order of magnitude than the sensitivity obtained using elastography techniques. This study opens new perspective for fast, cheap, and non-invasive mechanical characterization of non-linear soft tissues.
Desperate times call for disparate measures: Towards harmonization of cavitation data across environments and systems
Authors: Gray Michael , Coussios Constantin
Published: April 2023

As ultrasonic techniques rapidly evolve to provide a host of cavitation-mediated therapies, it is fair to ask: how can we reconcile thedata obtained across patients and hardware systems? This talk will describe progress made towards achieving system- and patient-independentcavitation localization and dosimetry. Methods and results will be presented for the characterization, quantification, and correction of biasing factors in the propagation path and receiver system. The talk will conclude with a discussion of limitations and ongoing efforts to demonstrate the full suite of proposed techniques.