bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of 3 MHz ultrasound in ex vivo scleral delivery of macromolecules of different sizes
Authors: Almogbil Hanaa H. , Nasrallah Fadi P. , Zderic Vesna
Published: May 2022

Therapeutic ultrasound offers a novel approach for enhancing scleral delivery of macromolecules for treatment of various ocular diseases. Our previous in vitro diffusion cell studies showed that 3 MHz ultrasound could enhance scleral delivery of Avastin (MW: 149 kDa). We tested similar ultrasound parameters in an ex vivo whole eye rabbit model by using fluorescently labeled FITC-dextran of various sizes (40, 70, and 150 kDa) to mimic the sizes of the current macromolecules drugs for treatment of retinopathies. 3 MHz ultrasound was applied for 5 min on the sclera of the eye submersed in a macromolecule solution, and then the eyes were left in the solution for another 55 min while in the 34.6 °C water bath. Ultrasound was not turned on for the sham-treated group. Temperature modeling was performed to assess the safety of 5-min ultrasound application in the eye. The fluorescence intensity values of FITC-150 group were statistically different (p < 0.05) between the ultrasound-treated (1809.4, n = 8) and their sham-treated group (1185.8, n = 8). However, the FITC-70 and -50 groups lacked any appreciable difference between their ultrasound-treated (1313.6, n = 8) and (1646.3, n = 6), and their sham-treated groups (1431, n = 8) and (1121.8, n = 6), respectively. Thermal simulations demonstrated a temperature rise of 4.6 °C, while experimentally the maximum temperatures was 4.4 °C.
Spectral analysis of Firefly Alpha launch noise
Authors: Yancey Matthew G. , Houston Griffin , Hart Grant W. , Mathews Logan T. , Bassett Michael S. , Durrant J T. , Gee Kent L.
Published: May 2022

On 2 September 2021, the first Firefly Alpha rocket launched from Vandenberg Space Force Base in California, USA. Acoustic data were collected at two locations 30 m and 60 m away from the launch pad, at another eight locations located on an arc with a radius of about 300 m, as well as an additional location roughly 8 km away. Around 14 s into the launch, an anomaly occurred, resulting in the premature shutdown of one of the four first-stage engines. By analyzing the overall levels and spectral characteristics of the rocket throughout the different phases of its flight, the effects of the engine shutdown on overall level and spectral peak frequency are discussed. Based on estimated engine parameters, the measured effects are compared to models for clustered nozzles.
Field validation of octave band sound modeling for wind turbines
Authors: Lodico Dana , Kaliski Ken , Butterfield Emma , Rost Hugo , Fitzgerald Shawn
Published: May 2022

The Sugar Creek Wind Project is a 57-turbine wind farm in Logan County, Illinois, with a capacity of up to 202 megawatts. Preconstruction sound modeling of the final Project layout was conducted in July 2019. Following construction of the Project, postconstruction attended sound measurements were made at 38 sites in the vicinity of Project turbines in September, October, and November 2021. Measured postconstruction sound levels were compared to the octave band sound level limits applicable under the Project’s Conditional Use Permit. A comparison of the modeled and background-adjusted measured octave band sound levels for the Project indicate that with the proper modeling parameters, octave band sound levels can be conservatively predicted.
Attended sound monitoring of wind turbines
Authors: Butterfield Emma I. , Lodico Dana , Kaliski Ken , Fitzgerald Shawn , Rost Hugo
Published: May 2022

Long-term unattended sound monitoring of wind turbines allows the selection of optimal data from a long period of time in which many meteorological conditions occur. However, in some cases, attended monitoring is required, either as a specific requirement of the permitting or because many measurement sites are required, making long-term monitoring impractical. Short-term attended monitoring of wind turbines introduces several complexities to ensure that the data are valid and representative of the target conditions. To illustrate this, we describe the challenges of attended octave band sound measurements made at 38 sites in the vicinity of wind turbines in Illinois in September, October, and November 2021. The attending monitoring was completed at night to reduce the background sound levels and involved the cooperation of residences, turbine operators, and the weather. Successful navigation of these challenges led to completion of the sound monitoring at all locations and acceptance of the study by the County.
Reflection of sonic boom over realistic urban areas
Authors: Dragna Didier , Emmanuelli Ariane , Ollivier Sebastien , Blanc-Benon Philippe
Published: May 2022

This study aims at analyzing sonic boom reflection over realistic urban areas. For this purpose, numerical simulations are performed. The 2D Euler equations are solved using high-order finite-difference methods, following Emmanuelli et al. [J. Acoust. Soc. Am. 149, 2437–2450 (2021)]. The local climate zone classification of urban morphologies [Steward and Oke, Bull. Am. Meteorol. Soc. 93, 1879–1900 (2012)] is used to generate ten typical geometries. Two booms, an N-wave and a low-boom wave, are considered. The pressure waveforms along the profiles are analyzed first. In addition to the geometric arrivals, low-frequency oscillations, associated with resonance modes of the street canyons, are noted. They induce an important increase in the duration of the signals. Their frequency and amplitude depend on the street width and on the boom wave. The noise levels are then investigated. Depending on the urban geometry, two behaviors are highlighted. For a sparse arrangement of buildings, the evolution of the levels is similar than for isolated buildings, with an amplification on the front facade and a reduction on the rear facade. For a dense arrangement, it is more complex due to the multiple reflections on the buildings. Finally, the levels follow a comparable evolution for both boom waves.
Low frequency (<1 MHz) transducers for intravenous sonothrombolysis
Authors: JIang Xiaoning , Zhang Bohua , Wu Huaiyu , Shi Chengzhi
Published: May 2022

Venous embolism is a great challenge in the treatment of a wide range of diseases, including cardiovascular diseases and cancers. Ultrasound-mediated thrombolysis (sonothrombolysis) presents a promising treatment of venous embolism. In this paper, miniature ultrasound transducers with frequencies ranging from 250 kHz to 800 kHz were developed for microbubble/nanodroplet-mediated intravenous sonothrombolysis tests. Relative low frequency (e.g., <1 MHz) is preferred because of the findings that cavitation plays an important role in sonothrombolysis, and microbubble-associated cavitation events can be enhanced at low frequencies. Small aperture (e.g. <2 mm × 2 mm) low-frequency transducers are usually known with high electrical impedance (e.g., >1000 Ω), which is not preferred for efficient electromechanical transduction. To address this challenge, multilayer acoustic stacks were designed, fabricated, and characterized. The measured electrical impedance of these stacks is mostly closer to 50 Ω, and the peak negative pressure is higher than 1MPa. These small aperture transducers were then used in in vitro- thrombolysis tests with unretracted and retracted blood clots, showing promising lysis rates. Other techniques such as laser ultrasound transducers, vortex wave generation, and magnetic microbubbles were also investigated for thrombolysis tests.
Amplitude and time-dependence of ultrasonic radiation force on modulation frequency computed from specular reflection contributions
Authors: Marston Philip L. , Daniel Timothy D. , Fortuner Auberry R. , Kirsteins Ivars P. , Abawi Ahmad T.
Published: May 2022

Ever since the late 1970s, there has been interest in the modulated radiation pressure of double sideband suppressed carrier (DSSC) ultrasound, because the associated radiation pressure oscillates at a single low frequency. Recent research considers situations, where the radius of curvature of the illuminated objects greatly exceeds the wavelength at the implicit carrier frequency of the ultrasonic illumination [Marston et al., J. Acoust. Soc. Am. 149, 3042–3051 (2021); 150, 25–28 (2021)]. Furthermore, the objects of interest, cylinders, and spheres in water are taken to be sufficiently highly reflecting that the radiation force can be shown to be dominated by contributions associated with specular reflection. In such cases, it is helpful to geometrically analyze the amplitude and time dependence of the oscillatory radiation force for perfectly reflecting objects, where the relevant integrals of the stress projections can be carried out analytically. The results are expressed using Bessel and Struve functions. They explain how the amplitude and phase of the force depends on the DSSC modulation frequency in agreement with partial-wave-series based calculations. The approach is relevant in other situations. [Work supported by the U. S. Office of Naval Research.]
Implementation of an ultrasonic fluid manipulation experiment on the International Space Station
Authors: Lirette Robert L. , Zhang Likun
Published: May 2022

The International Space Station (ISS) provides a unique opportunity to investigate acoustic radiation force interactions with a minimal interference from gravity. There are many design considerations to make when creating an experiment that is suited for use on board the ISS. NASA’s primary concerns with all experiments implemented in the ISS are with the safety of the crew and the success of the mission. Acoustic experiments are surprisingly rare on the ISS and present additional unique design challenges. This is especially true for experiments operated under water. Our work implements a high-intensity acoustic vortex beam under water for single droplet tractoring and capture operated inside the Microgravity Science Glovebox (MSG) on the ISS. The experiment payload consists of a signal generator, an amplifier module, and a sealed water chamber. A secondary fluid immiscible with water is injected into the chamber for acoustic manipulation, and the results of the experiment are recorded as high-definition video.
Acoustic angular momenta and their applications
Authors: Shi Chengzhi
Published: May 2022

Acoustic angular momentum is a physical quantity characterizing the rotation of pressure and local particle velocity fields. The acoustic angular momentum was first observed in vortex waves and was found to have many interesting physics including pseudospin based topological effects, spin-momentum locking, and trapping potential for contactless particle manipulations. In this presentation, we will introduce the categorization of acoustic angular momentum into spin and orbital angular momenta. While airborne sound is a longitudinal wave that was long thought to be spinless, we observed the acoustic spin in some special cases. The spin-momentum locking and spin induced torque for particle manipulation were experimentally demonstrated. In addition, the application of acoustic orbital angular momentum in high-speed communication will be discussed. These novel physical acoustic properties have many more applications ranging from underwater exploration to biomedical engineering.
Cortical encoding and cognition in reverberant speech perception in older adults
Authors: Muralimanohar Ramesh Kumar , Charney Lauren , Wróblewski Marcin , Molis Michelle R. , Billings Curtis J.
Published: May 2022

Older listeners are more susceptible than younger listeners to noise and reverberation when communicating in everyday environments. This study investigated the effects of hearing loss and cognitive processing ability on older individuals’ ability to perceive reverberant speech. The effects of reverberation were examined using three types of measures (1) electrophysiology: cortical auditory evoked potentials (CAEPs), (2) cognition: working memory and inhibitory control aspect of executive function, and (3) speech perception: syllable discrimination and sentence intelligibility. These assessments were carried out in two age- and sex-matched groups of ten olderadults (>50 years) with either normal hearing (thresholds ≤ 25 dB HL ≤ 4 kHz) or with mild-to-moderate hearing loss. First, the effect of reverberation on the cortical encoding in each group was determined; then, the effects of hearing loss and cognitive function on syllable and sentence perception were examined. Preliminary analyses showed that increasing reverberation negatively impacts speech perception and alters the amplitude and timing of peaks in evoked responses. Differential effects of reverberation across group will also be discussed. The outcomes of this study will help design clinically applicable models to assess individual susceptibility to environmental interference. [Work supported by an Early Clinical Investigator Grant from Medical Research Foundation of Oregon to R.K.M.]
Polarizability of electro-momentum coupled scatterers
Authors: Casali Matthew A. , Wallen Samuel P. , Goldsberry Benjamin M. , Haberman Michael R.
Published: May 2022

The macroscopic response of acoustic metamaterials with sub-wavelength asymmetry is described with coupled constitutive relations for the acoustic pressure and momentum density. This coupling leads to momentum that is dependent on the strain rate and pressure that depends on the local acceleration. The coupled constitutive form has become known as the Willis form because they were first predicted by John Willis [Wave Motion, 3(1), 1–11 (1981)]. The subwavelength behavior of the Willis material building-blocks can be described by a polarizability matrix relating the monopole and dipole scattering moments to the local pressure and velocities fields when off-diagonal terms are non-zero [Phys. Rev. B. 96(10), 104303 (2017)], providing a metric for the design of microscale structures leading to macroscopically observable Willis coupling. More recently, Pernas-Solomon and Shmuel showed that heterogeneous piezoelectric media with subwavelength asymmetry can lead to coupling between pressure, momentum density, and electric displacement fields, a material response known as electro-momentum coupling [J. Mech. Phys. Solids, 34, 103770 (2020)]. This work will present a polarizability description of electro-momentum coupled scatterers and the means to calculate the polarizabilities that couple local pressure, velocity, and electric fields with the aim of creating metamaterials for acoustic sensing. [Work supported by DARPA.]
Anomalous polarization in asymmetric gyroid structures
Authors: Keattitorn Saranchana , Carrillo-Munoz Maria , Sharma Bhisham
Published: May 2022

Recent studies show that structures with triply periodic minimal surfaces (TPMS) provide enhanced mechanical, acoustical, and energy abortion performance. Previously, we have shown that breaking the symmetry of the gyroid lattice—one of the most used TPMS geometry—results in the creation of directional and polarized bandgaps. Here, we focus on the effect of breaking symmetry on the effective wave speeds of the gyroid structure. We analyze the wave speeds of different asymmetric gyroid lattices using the finite element analysis approach. Our analysis shows that certain gyroid asymmetries result in the transverse waves propagating faster than the longitudinal waves in particular direction. Our research shows that breaking the symmetry leads to previously unobserved anomalous polarization of elastic waves in asymmetric gyroids.
Variability in the perception of race through voices and faces
Authors: Tripp Alayo , Smith Gisela , Munson Benjamin
Published: May 2022

Although perception of race is known to influence speech intelligibility, speech has often been studied without careful attention to this variability. It has been common to study language in an audio-only modality, which fails to capture the multimodal natures of language and person perception. We have developed a set of audiovisual study materials consisting of participants producing individual sentences selected from two different sets of standard materials. The corpus we have created is intentionally diverse with respect to racial self-report. However, there is extraordinary diversity in how persons who share a racial identification may present. The complex and variable relationship between physical features and the construction of social status demands that we reject reliance on self-reports when characterizing the diversity of our sample. In two experiments, participants viewed faces and listened to voices of people who contributed to the audiovisual corpus. The results allow us to explicitly characterize how the participants in the corpus may be racialized by observers, independent of their self-report. We argue that examining cognitive processes, which give rise to racialized and gendered perceptions, is foundational to advancing our understanding of speech perception in realistic environments with high degrees of variability in personal appearance and linguistic behavior.
Model-aided deep learning-based target detection for channel matrix-based cognitive radar/sonar
Authors: Ali Touseef , Bondre Akshay S. , Richmond Christ D.
Published: May 2022

Data driven based approaches to signal processing including deep neural networks (DNN) have shown promise in various fields. Such techniques tend to require significant training for good convergence. Model-based approaches, however, provide practical solutions often with insightful and intuitive interpretations. A hybrid approach that employs data driven techniques aided by knowledge from model-based approaches may help reduce required training and improve convergence rates. This work investigates the potential of deep learning techniques to detect targets while accelerating the learning process via use of expert/domain knowledge for the channel matrix based cognitive radar/sonar framework. The channel matrices characterize responses from target and clutter/reverberation. We will leverage our previous work [Ali et al. (2021); (2022)] on model-based adaptive detection approaches for cognitive radar/sonar. We compare the detection performance of model aided deep learning-based algorithms with that of traditional model-based techniques using receiver operating characteristic (ROC) curves from Monte Carlo simulations. We also study and compare the robustness of these techniques by changing the signal-to-interference plus noise ratio (SINR), the number of targets and clutter sources, and the amount of available training data. The effects of choice of hyperparameters and loss functions are also studied.
Adaptive transmit waveform design for active cognitive sonar using multi-tone sinusoidal frequency modulation
Authors: Hague David A.
Published: May 2022

Cognitive sonar systems leverage information gathered from earlier sensing interactions with the acoustic environment to adapt its system parameters for optimal performance. Of the many system parameters, an active cognitive sonar system could adapt, the acoustic signal projected into the medium, also known as the transmit waveform, has a profound impact on system performance as many of the physical characteristics of the acoustic environment are contained in the return echo signal. This research examines utilizing multi-tone sinusoidal frequency modulated (MTSFM) waveforms as an adaptive transmit waveform model for use in active cognitive sonar systems. The MTSFM waveform’s frequency and phase modulation functions are composed of a finite set of weighted sinusoidal harmonics. The weights for each harmonic are utilized as a discrete set of design coefficients. Adjusting these coefficients results in constant amplitude, spectrally compact FM waveforms that possess a wide variety of performance characteristics, which in the past required a diverse set of waveform types to achieve. The adaptability of the MTSFM waveform model enables a cognitive sonar system to generate waveforms that are finely tuned for the novel scenarios and environments that it may encounter.
Automated acoustic arrival matching using a convolutional neural network approach informed by statistics of acoustic scattering from internal waves
Authors: Graupe Cristian E. , Van Uffelen Lora , Howe Bruce M.
Published: May 2022

A machine learning model was developed to automatically align underwater acoustic measurements taken at various depths and ranges from a transmitting source in the Philippine Sea to a reference model of long range acoustic arrival structure, simultaneously determining source-receiver range and travel-time offsets associated with multipath arrivals. Ocean sound-speed variability complicates the task as the measured arrivals may exhibit scattering not present in range-independent predictions. Monte Carlo style broadband parabolic equation simulations through random internal wave fields consistent with the Garrett-Munk internal wave energy spectrum were used to generate a large data set of simulated acoustic receptions including scattered multipath arrivals with known source-receiver ranges and imposed travel time offsets. These simulated receptions were used to train and evaluate the machine learning model for arrival pattern matching to the reference model. The inclusion of various data dimensions, such as peak amplitude and width, and contextual information, such as range and depth, were also explored as input to the model. Ranging results for the machine learning model were compared to a programmatic solution engineered for the same task.
Empirical analysis of latent space encodings for submerged small target acoustic backscattering data
Authors: Linhardt Timothy , Sen Gupta Ananya
Published: May 2022

With future sights on specialized classification methods, we work to generalize the acoustic backscattering data from sonar measurements of small targets submerged in water by learning a non-invertible mapping (encoding) to a low-dimensional vector space (ℝn). Finding the optimal dimensionality of this latent space is an important task. The encoding is accomplished by utilizing modality agnostic convolutional machine learning methods that have seen success in other signal and image processing domains. We have explored the autoencoder and its variants, the sparse autoencoder, and the variational autoencoder. Autoencoders encode input samples from a high-dimensional manifold to a lower latent vector space and then reverse the lossy mapping back to a high-dimensional manifold similar to the initial domain. The sparse autoencoder induces sparsity in the components of the latent vectors, and the variational autoencoder learns an encoding to n-dimensional gaussian distributions instead of n-dimensional vectors. The TREX13 data are the primary dataset used for training the networks used in experiments. We evaluate the change in models’ accuracies as the latent dimensionality is increased as well as the models’ ability to generalize to unseen data. Additionally, the PONDEX09 and PONDEX10 data are used to evaluate the models’ cross-domain efficacy.
Case study: Acoustical design for newly renovated behavioral health suite
Authors: Holst Peter
Published: May 2022

This presentation addresses requirements and opportunities for the acoustical design of a behavioral design suite. Examples of coordinated design elements will be presented from a recent remodel project for a single suite in the UCSF Langley Porter Psychiatric Hospital and Clinics Mt. Zion relocation. The following will be presented. Unique components: Equipment transcranial magnetic stimulation (TMS) is a noninvasive procedure that uses magnetic fields to stimulate nerve cells in the brain, used to address depression. TMS therapy treatment equipment has a loud tapping noise that can be highly annoying to occupants of adjacent rooms. Sound isolation and sound-absorbing treatments are important design elements for a room with this equipment. Unique requirements: Patient safety behavioral health suites have unique patient safety requirements that led to the design selection for acoustical tamper-proof ceiling panels and specializd door gaskets at specific room types. Design considerations: Group therapy room group therapy rooms are in-patient areas that can consist of small and large groups, sometimes involving simultaneous group activities among patients and staff. HIPAA requirements, speech intelligibility, and occupant comfort, as well as hospital operations were important considerations for the coordinated acoustical design.
How toothed whales hunt with echolocation
Authors: Madsen Peter T.
Published: May 2022

The late Dr. Au developed a highly influential, quantitative framework for understanding the acoustic characteristics and performance of toothed whale biosonar systems. In his honor, I will apply this framework to the question of how echolocating toothed whales use their active sensory system to find, track and subdue prey in the field. Specifically, I will present data from echo-recording Dtags on wild toothed whales to show that they can detect, discriminate and approach prey with just a few tens of clicks, but that they use several hundreds of weak, high-rate clicks in the terminal buzz phase to track movements of elusive prey for capture in a very small sensory volume. I will use captive and wild data to demonstrate that toothed whales deliberately adjust their narrow beam sonars at short target ranges to receive weak prey echo levels within a 40-dB range above their hearing thresholds, and I will go on to argue that they do so to form simpler auditory scenes with less range ambiguity. I will end the talk by providing some perspectives on how Dr. Au’s emphasis on the synergy between captive and field studies is more relevant than ever if we wish to understand how toothed whales operate their biosonars under natural and Anthropocene conditions.
Inactivation of gram positive or gram negative microbes using different histotripsy regimes
Authors: Ambekar Pratik , Wang Yak-Nam , Khokhlova Tatiana D. , Leotta Daniel , Kuznetsova Ekaterina , Bruce Matthew , Matula Thomas
Published: May 2022

Abscesses are infected walled-off collections of pus and bacteria. They can affect any part of the body. Current treatment is typically limited to antibiotics, catheter drainage and hospitalization, or surgical wash-out. Although bacteria can develop drug resistance, they remain susceptible to thermal and mechanical damage. Histotripsy generates localized cavitation without heating and represents a potential new noninvasive treatment modality. Successful histotripsy treatments were demonstrated with gram-negative E-coli in both in vitro and in vivo studies [Brayman et al., UMB 44, 1996–2008 (2018); Matula et al., UMB 47, 603–619 (2020)]. Interestingly, preliminary data showed that boiling histotripsy was less effective than cavitation histotripsy in killing bacteria. In this talk, we will describe more in-depth studies that compare cavitation histotripsy (low number of cycles, high-pulse repetition rate) with boiling histotripsy (high number of cycles, low-pulse repetition rate) on inactivation rates of microbes. [Work funded in part by NIH NIBIB No. R01EB019365.]
Instantaneous phase difference of nonlinear coupled bubbles from nonstationary forcing
Authors: Hayashi Rintaro , Allen John S.
Published: May 2022

The attraction and repulsion regimes of acoustically forced bubbles follow from their phase coupling. The direct evaluation of phase difference has received less attention than the secondary Bjerknes force, though it has important implications for nonlinear, nonstationary forcing regimes. We numerically investigate the response of two nonlinearly coupled bubbles undergoing radial oscillations and translation from chirp forcing. The corresponding scattered acoustic responses are analyzed using the empirical mode decomposition (EMD) and Hilbert transform in terms of respective instantaneous amplitude, frequency, and phase. This allows for determination of the phase differences from the coupling between the two bubbles. The phase coupling results agree with previous analytical theory in the linear acoustic limit. Attraction and repulsion regimes for nonstationary forcing can be classified with respect to the instantaneous phase differences unlike the time averaged secondary Bjerknes force. In the nonlinear regime, the chirp direction (forward, backward) results in significantly different radial and translational responses. This result can be explained with respect to influence of the softening jump discontinuity (backbone curve) on the phase coupling. Notably a backward chirp results in overall greater amplitude response and thus more translation during attraction. Implications for optimal waveforms are highlighted for potential applications.
Combining ultrasound and endovascular laser for thrombolysis
Authors: Singh Rohit , Jo Janggun , Yang Xinmai
Published: May 2022

Blood clot formation in vein, known as venous thromboembolism is a major disease worldwide. Ultrasound and laser-based treatment techniques have been developed to remove blood clots and recanalize occluded vessels. The applications of both technologies are hindered by their individual limitations. We tested a novel hybrid technology based on the spatio-temporally synchronized pulsed laser and ultrasound, namely, ultrasound-assisted endovascular laser thrombolysis (USELT) in an in-vitro- blood clot model and invivo rabbit model. The in vitro- study demonstrated enhanced thrombolysis with USELT as compared with ultrasound-only and laser-only. In in vivo study, out of seven treated rabbits in USELT group, the vein was fully or partially recanalized in five rabbits and poorly recanalized in two rabbits, whereas the vein treated with ultrasound-only and laser-only did not result in recanalization in any case. The in vitro- and in vivo study successfully demonstrated the feasibility of USELT for thrombolysis, and USELT has the potential to combine the advantages of both ultrasound and laser thrombolysis techniques and overcome their limitations.
Streamlining ASTM acoustical standards
Authors: Dick Elliott , Rawlings Samantha , Shafer Benjamin M. , Golden Matthew
Published: May 2022

ASTM E33, the Committee on Building and Environmental Acoustics, has decided to undertake a process to streamline and harmonize existing E33 standards. As the committee’s standards have developed over the decades, inconsistencies, omissions, and contradictions have wound their way into the standards due to cross-references among standards and revisions. Members of this committee volunteered to spearhead an effort to restructure the standards with the goal of making the standards easier to understand, simpler to use, and to facilitate future revision efforts. This paper summarizes the beginnings of this effort and steps being taken at this time.
Experimental investigation of the variance of ground impedance measurments in coastal environments
Authors: Cobb Faith A. , Vecchiotti Andrea , Turo Diego , Vignola Joseph , Ryan Teresa J.
Published: May 2022

The purpose of this work is to understand the results obtained with the ANSI/ASA S1.18 standard for outdoor acoustic surface impedance measurements when applied to surfaces with characteristics at or outside the recommended use case. This study is part of a larger effort working to develop a numerical model for long-range atmospheric acoustic transmission loss over coastal areas. Previous studies were done to characterize the relationship between moisture content and effective flow resistivity of sandy shores by conducting acoustic surface impedance measurements following the procedure specified in the ANSI/ASA S1.18. While the standard specifies surface variation of less than 5 cm and at least four measurements per location, this work seeks to understand the consequences of surface variation in natural terrains on the obtained results. These consequences were evaluated by measuring the effective flow resistivity of multiple outdoor surfaces such as uniform grass, raked sandy shores, and undisturbed sandy shores. At every location, 16 measurements were performed in grid pattern. Subsets of the 16 measurements are used to perform an analysis of the variance of the measured flow resistivities collected at locations with different surface characteristics.
Analysis of focus boom test cases using the lossy nonlinear Tricomi equation
Authors: Salamone Joseph A.
Published: May 2022

Focused sonic booms will result from an aircraft accelerating from subsonic to supersonic airspeeds. Sonic boom focusing leads to amplification and phase change of the sonic boom signature and can be modeled by a form of the nonlinear Tricomi equation. This presentation will use the lossy nonlinear Tricomi equation (LNTE) to examine sonic boom focusing for two sample cases. The first case depicts an aircraft with constant rectilinear acceleration at a constant altitude. The second case is slightly more complicated with an aircraft maneuvering at a small climb angle, while accelerating and simultaneously pitching downward. Time-pressure histories at various locations in the illuminated zone above the caustic and in the evanescent zone below the caustic will be provided for each test case.
Synthesizing acoustic drill beams by the superposition of detuned vortices
Authors: Jiménez Noé , González-Mateo Enrique , Camarena Francisco , Staliunas Kestutis
Published: May 2022

We present acoustic drill beams. These singular beams show a dynamic intensity distribution matching the shape of a helix. The intensity distribution rotates along the axis of the beam with a controlled direction and angular frequency, therefore resembling the shape of a mechanical drill bit. Acoustic drills emerge elegantly as the spatio-temporal interference of two confocal and detuned vortex beams. The beam parameters are fully tuneable. The detuned frequency, detuning wave number, and detuned topological charge of the composing beams control the number of arms of the drill, the winding period, the rotation velocity, and its direction. We show that elongated drill beams are obtained using two high-order Bessel beams, enabling analytical solutions for optimal overlapping. In addition, drill beams can also be synthesized by focused ultrasound vortices. Analytic, numeric, and experimental results are shown in the ultrasound regime using a low-cost device based on two confocal 1-MHz piezoelectric transducers and 3D-printed acoustic holograms. This new wave structure opens novel avenues for wave-matter interaction such as contactless particle manipulation, matter processing, or biomedical applications.
Comparing frequency-chirp sensitivity in the inferior colliculus to basic response properties using novel stimuli
Authors: Mitchell Paul , Carney Laurel H.
Published: May 2022

Most neurons in the central nucleus of the inferior colliculus (ICC) are sensitive to the direction of phase-curvature of Schroeder-phase (SCHR) stimuli. This phase-curvature controls the direction and velocity of frequency chirps within the fundamental SCHR period. Differences in responses to different SCHR stimuli may originate from an underlying sensitivity to frequency chirp direction or velocity. However, known ICC sensitivities, such as those to frequency or envelope periodicity and duty cycle, may also contribute to the observed effect. To parse these confounding SCHR stimulus features, we designed novel frequency-chirping stimuli to isolate the influences of periodicity, duty cycle, and frequency-chirp direction or velocity on ICC neuron responses. Extracellular, single-unit recordings of chirp responses were made in awake rabbit ICC. Simultaneously, basic response properties were characterized using methods such as frequency response maps, modulation transfer functions, and spectro-temporal receptive fields. By comparing basic response properties across chirp-sensitive neurons (comprising 80% of ICC neurons), we can outline the shared characteristics among them. Our goal is to determine whether frequency-chirp sensitivity in ICC neurons is independent of other established feature sensitivities. Frequency-chirp-sensitive neurons are interesting, because they may play a unique role in encoding sounds with complex phase, including speech. [Work supported by NIDCD-R01-001641.]
Evaluating central auditory processing in Veterans using population-appropriate norms
Authors: Stadel Lauren , Zhen Leslie , Gallun Frederick J. , Jedlicka David , Haley Elizabeth , Jorgensen Lindsey , Novak Michelle , Dann Serena , Baugh Lee , Fercho Kelene , McNeil Malcolm , Pratt Sheila
Published: May 2022

Increasing numbers of military Veterans have reported substantive self-perceived hearing handicap despite normal/near normal hearing on standard audiometric testing. These hearing difficulties are especially true for Veterans with histories of blast exposure and presumed mild traumatic brain injury, with many of these Veterans also being comorbid for post-traumatic stress disorder (PTSD). Clinical tests of Central Auditory Processing Disorder (CAPD) commonly are used to investigate their hearing concerns, but performance on CAPD tests typically is compared to published norms established from non-Veteran populations. Since Veterans and non-Veterans differ significantly in many relevant domains, using non-Veteran norms is potentially problematic for the interpretation of CAPD test results. Veterans (n = 217; with and without histories of blast exposure and PTSD) completed a large CAPD test battery. An N = 1 approach was used to compare the performance of the blast-exposed Veterans and those with PTSD to published norms and data from the Veterans without histories of blast exposure and PTSD (control group). The number of abnormal cases identified based on the Veteran control group was lower than that found with the published norms for all tests. Therefore, establishing and using population-appropriate norms are critical for accurately diagnosing CAPD in Veterans.
A spatially-aware dialogue system for immersive classrooms
Authors: Chang Albert , Si Mei , Chabot Samuel , Mathews Jonathan , Strzalkowski Tomek , Braasch Jonas
Published: May 2022

Dialogue systems have become a popular research medium as recent advances in task-oriented and open-domain systems combined with deep learning technologies have increased the potential for practical applications across many disciplines. One such vein of applications involves multi-modal dialogue systems deployed in interactive spaces that seek to provide an immersive experience for participants. This project proposes a combination of spatial awareness with a multi-modal, immersive dialogue system as a potential interactive medium to provide an additional layer of immersion. The system employs an array of audio/visual sensors that tracks participants within the interactive space. It responds contextually depending on the application and information domain, for example, by displaying and sonifying conversational agents at accurate spatial locations. The current application of this system involves Mandarin language learning in which the system will act as both a learning medium and conversation augmentation system to provide students with an immersive environment to learn a language and provide real-time feedback during the learning process. This project aims to provide insight into interactive spaces for education and general conversation applications, and demonstrate the capabilities of combining spatial awareness with a multi-modal dialogue system. [Work supported by NSF IIS-1909229, IBM GATOR, and CISL.]
Deconvolution filter for parameter estimation of composite stress wave propagating in the wooden cylindrical structure
Authors: Lee Yishi
Published: May 2022

Through-transmission using the embedded waveguide technique in the cross-section plane of cylindrical structure produces radial and Rayleigh modes. These two modes propagate in the heart and shell regions of the plane, allowing a comprehensive characterization of the material. The significant spatial difference generates a distinct temporal separation between the two modes for large cylindrical structures, allowing direct mode characterization. For cylindrical structures with smaller diameters, the pronounced multi-path interference produces an erroneous energy response that hinders the accurate mode characterization. In this so-called multiple-input-single-output (MISO) system, the arrival time and amplitude estimations are an underdetermined problem. This work presents a novel decomposition filter design consisting of three steps. (1) Gabor’s wavelet transforms the stress wave signal in the time-frequency domain; (2) The approximation of the inverse point-spread-function (PSF) response via a series of frequency polynomials generates a set of optimal coefficients; (3) Derive the inverse deconvolution kernel via the dual derivative operator from the obtained optimal coefficients in step 2. This presentation will demonstrate the algorithmic formulation with numerical and empirical validations. Its broader impact will enhance the parametric estimation of the diagnostic stress wave for material characterization.
John Preston’s contributions to ONR collaborative research efforts
Authors: Becker Kyle M.
Published: May 2022

The Office of Naval Research (ONR) was established by public law in 1946 to plan, foster, and encourage scientific research in recognition of its paramount importance as related to the maintenance of future naval power. To fulfill its mission, the ONR model is to invest not only in ideas, but in people. It seeks to attract and retain high performing scientists and engineers to lead and collaborate on research that is recognized nationally and internationally for its quality and importance. Dr. John R. Preston was an exemplar of the ONR model. This presentation will feature the many and various contributions John has made to the scientific community through his ONR supported work. It will emphasize the scientific relationships and outcomes John fostered, both nationally and internationally, in academia and government by his championing development of the ONR Five Octave Research Array (FORA). Under John’s stewardship, the FORA became a community asset that was used in a host of different experiments, deployed from a variety of different platforms, and operated in many different environments. John’s unselfishness, dedication, and enthusiasm for working with an ever growing number of partners have made FORA a great success for both ONR and the community.
Absorption measurements—A never ending story?!
Authors: Nocke Christian
Published: May 2022

A brief historical review on measurement techniques of sound absorption or the acoustic surface impedance will be presented, starting from procedures in the 1930s. Many in situ and laboratory methods have been described over the years. Most of these methods are based on the assumption of plane wave propagation or diffuse sound field. Measurement examples will be shown for some of the methods presented and compared to each other. A commonly used measurement procedure of so-called diffuse sound absorption coefficients is described in the international standard ISO 354. The present revision of the standard only focuses on the conditioning of the sound field and further applying Sabine equation. A diffuse sound field is atheoretical approach. Geometrical acoustics as the basis of sound field simulation has been applied to measurements in a virtual reverberation chamber on absorber baffle set-ups [see Probst (2015)] and showed good agreement between measured and calculated values. This approach is used to investigate the effect of sample size and sample position. Correspondingly, non-standard measurements are compared with simulation results.
A multipole model-based boundary admittance estimation for wave-based room-acoustic simulations using Bayesian inference
Authors: Chen Ziqi , Xiang Ning , Horoshenkov Kirill V.
Published: May 2022

Room-acoustic simulations for sound wave propagation require significant knowledge of the boundary conditions for the room boundary surface. This work presents the application of model-based Bayesian inference on the surface admittance estimation problem. First, this work deals with selecting the multipole admittance model through the higher level of inference, Bayesian model selection. And the parameters of the chosen multipole admittance model are estimated through the first (lower) level of inference, Bayesian parameter estimation. This work focuses on the approximation of the surface admittance as a function of frequency given a set of acoustic admittance. This frequency-dependent admittance is deduced either from the experimental measurements of a porous material or numerical predictions in order to demonstrate wave-based boundary conditions to incorporate arbitrary admittance functions with frequency ranges under consideration. According to the analytical results and numerical verifications conducted in this work, Bayesian inference based on the multipole model is well-suited for the estimation of the frequency-dependent boundary conditions within a wave-based simulation framework.
Boundary element method virtual goniometer to predict the diffusion and scattering coefficients
Authors: D'Antonio Peter , Ferraz Alvim Luiz Augusto T. , Petrolli Rinaldi P.
Published: May 2022

The experimental measurement of the diffusion coefficient according to ISO 17497-2 is very time consuming and requires several sample periods to evaluate the effect of diffraction lobes, an anechoic or large reflection-free volume and far-field conditions. Wave-based BEM methods have predicted diffusion and correlation scattering coefficients very accurately [Hargreaves et al., J. Acoust. Soc. Am. 108 (4), 1710–1720 (2000)]. This presentation will describe a new Python Virtual Goniometer program, called VIRGO, which predicts the free-field and surface-mounted diffusion and correlation scattering coefficients for any shaped surface that can be successfully meshed from a three-dimensional file. The program accurately predicts the periodic diffraction grating lobes of a reference one-dimensional hemicylinder and a two-dimensional hemisphere, both in the free-field and surface mounted on a boundary. The diffusion coefficient and three-dimensional polar responses of additional number-theoretic and optimized profiled and curvilinear shapes will also be compared with scale model boundary-plane goniometer measurements. The results will verify that it is possible to precisely predict the diffusion and correlation scattering coefficients, without having to fabricate or 3D print scale models or full-scale samples.
Pre-pulse inhibition of the acoustic startle response as a behavioral assay for sound localization abilities of the Mongolian gerbil
Authors: Sergison Matthew D. , Peacock John , Benson Monica A. , Poleg Shani , Greene Nathaniel , Klug Achim , Tollin Daniel
Published: May 2022

The Mongolian gerbil (Meriones unguiculatus) has been used to investigate mechanisms of binaural and spatial hearing. However, behavior assays used to test gerbil spatial hearing using operant conditioning are very time consuming. Pre-pulse inhibition (PPI) of the acoustic startle response offers a method that requires no training and is thus high throughput. Here, we examine whether PPI can be used to assess spatial hearing in gerbils. In eight gerbils, we presented a continuous broadband noise that swapped speaker locations as a pre-pulse prior to a startle stimulus and found PPI increased with wider angles of swaps. Swap angles at 30° (±15° re: midline) or higher showed significantly higher PPI compared to baseline for swaps across midline and in each hemifield. We also performed speaker swap with a low- (0.5 kHz) and high-pass (4 kHz) filter and found that PPI increased at wider angles for both conditions. PPI also increased at wider angles and lower intensity of a spatial broadband masker to a broadband chirp pre-pulse. We successfully demonstrate the gerbil’s sound localization abilities and show that PPI paradigms are capable of quickly testing large numbers of gerbils and reveal performance similar to operant conditioning methods. [Work supported by R01-DC017924.]