bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantifying information content of modal dispersion data in geoacoustic inversion
Authors: Dosso Stan , Bonnel Julien
Published: November 2022

This paper illustrates the information content of ocean acoustic modal-dispersion data to constrain parameters and uncertainties of seabed geoacoustic models. In particular, time-frequency warping analysis is applied to extract dispersion data consisting of arrival times as a function of frequency for 18 of the first 21 propagating modes from recordings of an impulsive sound source on a vertical hydrophone array. To quantify the information content of these dispersion data to resolve seabed structure, a Bayesian inversion formulation is applied that includes rigorous approaches to model selection and data error modeling. Model selection considers both layered and gradient representations of seabed profiles using trans-dimensional inversion and Bernstein-polynomial basis functions, respectively. In both cases, model parameterizations are determined probabilistically from the data as part of the inversion. The error model assumes a multi-variate Gaussian distribution with unknown variance and covariance for each mode; covariance estimation is formulated in terms of trans-dimensional sampling of zeroth- and first-order autoregressive processes. The applicability of these assumptions/approaches is validated with qualitative (graphical) and quantitative residual analyses. Results are considered as marginal probability profiles for geoacoustic properties, which quantify the resolution of seabed structure versus sub-bottom depth. [Work supported by the Office of Naval Research.]
Lisa Zurk’s contributions to striation-based signal processing for active sonar
Authors: Rouseff Daniel , Schecklman Scott , Quijano Jorge
Published: November 2022

Strong multipath propagation adds considerable complication to acoustic signal processing in the ocean. When mapped in range-frequency space, the acoustic field exhibits striations, alternating bands of high and low intensity due to constructive and destructive interference between the paths. Nearly forty years ago, Russian scientists showed how this striation pattern could be described by a single scalar parameter, the so-called waveguide invariant that subsequently became a staple of their passive sonar signal processing methods. Lisa Zurk’s contribution was to show how a striation-based approach could be adapted to active sonar processing. Together with her students, she did tank experiments and analysis for monostatic and bistatic configurations. For a horizontal array, she developed a beamformer featuring a linear frequency shift across the array designed to align with high-intensity striations. The result was improved performance in noisy environments. She showed how the waveguide invariant can improve tracking accuracy by providing a constraint on possible tracks. She and her students demonstrated the improved tracking with continuous active sonar data. Lisa Zurk’s innovative work on these topics continues to inspire present day research.
Extension of boiling histotripsy lesions by axial focus steering during pulse delivery
Authors: Thomas Gilles P. , Khokhlova Tatiana D. , Sapozhnikov Oleg A. , Khokhlova Vera A.
Published: November 2022

Boiling histotripsy (BH) is a pulsed high intensity focused ultrasound (HIFU) method relying on the generation of high amplitude shocks and bubble activity to induce tissues liquefaction. A sequence of pulses, 1–20 ms long, generates boiling bubbles at the focus of the HIFU transducer within each pulse, and the remainder of the pulse then interacts with those bubbles. One effect is the creation of a prefocal bubble cloud due to shock scattering: the shock is inverted when reflected from the bubble wall resulting in sufficient negative pressure to reach intrinsic cavitation threshold immediately proximally to these bubbles. Here, a methodology is proposed to extend the length of this prefocal bubble cloud by steering the focus toward the transducer during the BH pulse and thus accelerate treatment. A BH system comprising a 1.5 MHz 256-element phased array connected to a Verasonics V1 system was used. High-speed imaging in transparent gels was performed to observe the extension of the bubble cloud resulting from shock scattering. Volumetric BH lesions were generated in ex vivo tissue. Results showed a threefold increase of the volumetric ablation rate with focus steering compared to standard BH. [Work supported by NIH R01EB007643, R01GM122859, and R01EB25187.]
Extending the Iterative Nonlinear Contrast Source method to simulate mutual interaction in large populations of microbubbles
Authors: Verweij Martin D. , Matalliotakis Agisilaos
Published: November 2022

There is an ongoing development of ultrasound contrast agents (UCAs) for specific medical diagnostic and therapeutic applications. Recent researches involve all kinds of targeted and loaded microbubbles, monodisperse microbubbles, and phase-change nanodroplets. To design and improve applications that use UCAs, it is necessary to have a thorough understanding of the mutual interaction of ultrasound fields and UCAs. The individual response of microbubbles and nanodroplets is extensively studied and, in the case of bubbles, multiple variants of the Rayleigh-Plesset equation are available to describe their behavior. However, novel applications, such as therapeutic proton beam localization, may strongly depend on the mutual interaction in a population of UCAs. In this presentation, a numerical approach for the analysis of ultrasound-bubble interaction in a population with many (order one million) microbubbles will be discussed. This approach is based on the earlier developed Iterative Nonlinear Contrast Source (INCS) method for simulating nonlinear ultrasound waves. In the current case, the population of microbubbles will be represented by a set of pressure-dependent contrast point sources that are iteratively updated by the INCS method, where each iteration adds an order of multiple scattering. Results will be presented for the linear scattering in populations with different concentrations of microbubbles.
Intrusive temperature measurement of the cavitation bubbles using cold wire
Authors: Subramanian Roshan Kumar , Coutier-Delgosha Olivier
Published: November 2022

Cavitation is a phenomenon of rupturing a liquid when the liquid is subjected to a decrease in pressure at roughly constant temperature. Cavitation is the fundamental reason for the material erosion when the bubbles are collapsing closer to the surface. These bubbles also produce a very high temperature (thousands of degrees Celsius) for a very short time (in the order of nano or microseconds). Cavitation is also being used in the non-invasive cancer tumor ablation treatment using high intensity focused ultrasound (HIFU) called histotripsy. So, our research in measuring the temperature of the bubble collapse will help the histotripsy treatment to understand its thermal behavior. We have designed a cold wire sensor of the thickness of ∼10 to 50 micrometers. And, the sensing region is 2 millimeter. These cold wires are made with kevlar or nylon fibers, titanium, nickel, silver, and silicon dioxide. The single bubble or histotripsy cloud, is allowed to collapse on the sensor, and we measure the temperature based on its change in resistance. These changes in resistance are corresponded to the temperature using the mathematical function which is calibrated prior to the experiment. We measure it in three different experimental settings like Tube Arrest Method (TAM), LASER induced bubbles, and HIFU induced bubbles. The preliminary results have shown that the temperature of the single spherical bubble collapse (TAM) can rise to thousands of degrees celsius as mentioned in the literature based on the theoretical analysis.
Why use the finite difference time domain method for studying echolocation bats?
Authors: Teshima Yu , Tsuchiya Takao , Hiryu Shizuko
Published: November 2022

To study bat echolocation, it is essential to investigate echoes containing environmental information that bats use to determine their behavior. However, even with the recent advanced technique, it is difficult to measure all echoes reaching the bats in flight. Therefore, we proposed an approach that combines behavioral measurements (flight path measurements using high-speed video cameras and emitted ultrasound measurements using a telemetry microphone attached to the bat's back) with the FDTD method to calculate echoes from the surroundings, resulting in new behavioral findings. Analysis of binaural echoes reaching the bats in flight suggested the space composed of echo information is different from the visually perceived space, and the Doppler shift compensation behavior of bats revealed the transition of attention during flight by extracting echoes that bats pay attention to. In addition, by introducing a 3D digital model of a bat's head into the simulation space, we were able to study the echo information required for bat source localization based on the head transfer function. The proposed method enables the acquisition of echoes, which has been a longstanding problem in bat echolocation research and is a promising new method that could lead to a better understanding of bat behavior decisions.
Simple insertion loss calculations executed using a 13 point 3d FDTD scheme
Authors: van der Harten Arthur W.
Published: November 2022

Simple applications of a 13 point finite difference time domain method have been developed to address difficult problems concerning the attenuation of particularly complicated noise attenuation problems. When in doubt concerning engineering equations for sound attenuation, a wave-based technique can be a practical tool for determining the attenuation due to obstructions and physical structures. Several instances ranging from mechanical applications, site noise problems, and architectural features are presented.
Fostering relationships between industry and academia is good business
Authors: DeGrandis Jim
Published: November 2022

From the perspective of an industry manufacturer, it is sometimes difficult to promote activities such as academic outreach and research. While business-to-business investments are commonplace and provide the most direct investment-to-return ratio calculation, some companies find that allocating resources for academia provides long-term benefits and opportunities. The symbiotic relationship between business and education helps manifest research resources, knowledge exchange, mentoring, and future opportunities for the students, staff, facilities, and industry as a whole. Here are some cases where investing in the intangible relationships with academia proved to be good business.
Internships in the acoustical disciplines: How can we attract a more diverse student population?
Authors: Doggett Felicia M.
Published: November 2022

A problem that many professional scientific organizations are tackling now, including the Acoustical Society of America (ASA) and the Institute of Noise Control Engineering (INCE), is the lack of diversity in our current membership. As the chair of INCE’s Diversity, Equity, and Inclusion committee, we are exploring ways to engage with a more diverse student population for both internships as well as fulltime employees after graduation. In 2021, the National Science Foundation (NSF) published Women, Minorities, and Persons with Disabilities in Science and Engineering, which provides statistical information about the participation of these three groups in science and engineering education and employment. In order to have a plan as to how to proceed engaging with students, this document provides a good benchmark as to the current enrollment in the United States. This presentation explores methods that INCE’s DEI committee is implementing to reach out to students and connect them with companies and industries in acoustics and noise control engineering who can make internships possible.
Assessing the impact of ground reflection on measurement of the overall sound power level and acoustic radiation efficiency of rocket launches
Authors: Hart Grant W. , Gee Kent L.
Published: November 2022

Determining the sound power levels of a rocket is the first step in characterizing its radiation efficiency. Because the sound radiation from a launch vehicle is anisotropic, well-calibrated ground measurement stations are used, along with trajectory data, to obtain sound power. Historically, the effect of ground reflections appears to largely have been neglected in the literature, despite the potential to inflate OAPWLs and therefore radiation efficiency. This study investigates the likely effect of a finite-impedance ground on spectra, overall sound pressure levels, and power levels. The single-parameter ground reflection model by Embleton et al. [J. Acoust. Soc. Am. 74, 1239–1244 (1983)] is used to obtain an estimate for change in OASPL for a model spectrum based on space vehicle launches. When the correction is applied to the OAPWL it produces in a nearly 3dB reduction in level and reducing the efficiency by a factor of 2. This indicates the possibility that the 0.5% radiation power efficiency assumed for rockets in the past is too high.
Implementing a heuristic method to correct ground reflection effects observed in full-scale tactical aircraft noise measurements
Authors: Christian Matthew A. , Gee Kent L. , Streeter Jacob B. , Wall Alan T. , Campbell Steven C.
Published: November 2022

In a recent study of noise from a T-7A-installed GE F404 engine, microphones along 38 and 76 m (125 and 250 ft) arcs were mounted 1.5 m (5 ft) above the ground to quantify human impact. While helpful for this purpose, the resulting multipath effects pose challenges for other acoustical analyses. For jet noise runup measurements, these effects are complicated by the fact that the noise source is extended and partially correlated and its spatial properties are frequency dependent. Furthermore, a finite-impedance ground surface and atmospheric turbulence affect interference nulls. This study applies a ground-reflection method developed previously [Gee et al., Proc. Mtgs. Acoust. 22, 040001 (2014)] for rocket noise measurements. The model accounts for finite ground impedance, atmospheric turbulence, and extended source models that are treated as coherent and incoherent arrays of monopoles. Application to the ground runup data to correct the 38 and 76 m spectra at a range of angles suggests the incoherent line source model is more appropriate at sideline angles whereas the coherent source model is more appropriate for upstream and downstream propagation. Comparisons with near-field data and similarity spectra show that, while imperfect, this method represents an advancement in correcting jet noise spectra for ground reflection effects. [Work supported by ONR Grant No. N00014-21-1-2069.]
Source decomposition and reduced-order modeling of an installed F404-GE-103 engine using the optimized-location virtual reference method
Authors: Mathews Logan T. , Wall Alan T. , Gee Kent L.
Published: November 2022

Principal component analysis-related methods (i.e., proper orthogonal decomposition or partial field decomposition) are used widely in aeroacoustic applications for source characterization and reduced-order modeling. A previous paper [A. T. Wall et al., J. Acoust. Soc. Am. 144, 1356 (2018)] developed a coherence-based, virtual-reference method for performing physically meaningful PFD known as the optimized-location virtual references (OLVR) method. This paper performs a source decomposition using the OLVR method on acoustical holography data from an installed GE F404 engine. The OLVR-derived partial fields are compared with far-field radiation characteristics and partial equivalent sources are fitted to analytical wavepackets. Characteristics of this reduced-order model are discussed as a function of frequency and engine condition. [Work supported ONR Grant No. N00014-21-1-2069.]
Near-field coherence analysis of noise from an installed F404 engine
Authors: Epps Kristi A. , Olaveson Tyce , Gee Kent L. , Wall Alan T. , Swift S. Hales
Published: November 2022

Because phenomena observed in noise radiated from high-performance military aircraft are not fully understood, different analysis techniques can yield complementary insights into their characteristics. Here, a coherence analysis from a 120-microphone near-field array is used to identify and characterize the noise radiation and source-related properties of a T-7A-installed F-404-GE-103 engine over a broad range of frequencies. Some of the noteworthy findings include: a) coherence trends for mixing noise and spatiospectral lobes generally match those observed for previously studied aircraft; and b) bands of coherence between upstream and downstream locations are observed at higher engine powers, suggesting a coherent interaction between upstream broadband shock-associated noise radiation and downstream Mach wave radiation. [Work supported by ONR Grant No. N00014-21-1-2069.]
Distributed acoustic sensing with optical fibres: Fundamentals and applications
Authors: Masoudi Ali , Brambilla Gilberto
Published: November 2022

Because of their intrinsic geometrical features and extraordinary transparency, optical fibers allow for a continuous and dynamic monitoring of strain along all their length. In state of the art systems, 100 000 points can be resolved over a range of the order of 50 km, providing an extremely cost effective solution per sensing unit. In its basic implementation, a light pulse is injected into the sensing optical fibre and the Rayleigh backscattered light is continuously monitored, in a process similar to a radar system. While the phase relation between different point along the fiber is used to reconstruct the strain (thus the acoustic information), the time of flight (e.g., delay between injected pulse and received backscattered light) provides information about the physical location along the fiber. In the last decade, research on novel detection schemes and fibers has allowed to extend the detection range to over 170km, to decrease the spatial resolution below 10 cm and significantly increase the signal-to-noise-ratio. Because of this, distributed acoustic optical fiber sensing (DAS) has found applications in the oil and gas industry for oil well monitoring and geoseismics and more widely for the monitoring of border and perimeter security, resulting in market of the order of $1 billion. More recent applications include monitoring of railways and road traffic, structural health, earthquakes and other geophysical events.
Voicing and manner of articulation in L2 perception: The role of markedness
Authors: Alkahtani Faisal
Published: November 2022

Arabic labial obstruents exhibit gaps in voicing: both the voiceless stop /p/ and the voiced fricative /v/ are absent. Thus, Arabic speakers learning English must acquire the missing labial segments along with segments that are already in their phonemic inventory. In this study, I examine markedness in L2 acquisition of English by Arabic speakers, focusing on its role in perception. Specifically, I test two general markedness patterns: (a) stops are unmarked relative to fricatives and (b) voicing contrast in word-initial position is unmarked relative to word-final position. If unmarked sounds are easier to acquire than marked ones, we may expect Arabic speakers to perceive the new segment /p/ better than /v/. Moreover, their perception of the voicing contrast in word-initial position should be better than in word-final position. 31 Saudi Arabic speakers heard 144 nonce words produced by a native speaker of English. The words included: /p/, /b/, /f/ and /v/ in word-initial or word-final position. Results showed Arabic speakers were significantly better at perceiving the fricative /v/ than the stop /p/ (p < .01), contrary to what was expected, suggesting that the acoustic cues of fricatives are perceptually more prominent. The markedness relation was, however, observed with better perception word-initially than word-finally.
Perception of English lexical stress in different intonational contexts by Mandarin listeners
Authors: Yang Tzu-Hsuan , Tremblay Annie C.
Published: November 2022

The present study seeks to elucidate the nature of first language transfer effects on the perception of English lexical stress in different intonational contexts. Pitch (F0) is one of the acoustic cues to lexical stress in English, but crucially, pitch can only serve as a cue to stress when interpreted within the intonation system of English. In contrast, Mandarin is a tonal language where pitch carries greater functional weight for signaling lexical contrasts. Associating pitch to lexical contrasts, Mandarin listeners might therefore assume a one-to-one relationship between pitch and lexical stress in English. To examine whether Mandarin learners of English make this assumption, the current study tested their stress perception in four different intonations: H*L-L%, L*H-H%, H*H-H%, and L*L-L%, where F0 cues to stress were realized differently in each intonation. The results of the stress identification task showed that Mandarin listeners falsely associated higher F0 with stress and lower F0 with the absence of it, and their performance did not improve as they became increasingly proficient in English. The findings provide corroborating evidence for the Cue-Weighting Transfer Hypothesis by showing that the use of a suprasegmental cue can transfer from one phonological category (tones) to another (stress).
Evaluating how language and masked-speech recognition change over time for bilingual children in the Midwest
Authors: Garcia Stefani , Cowan Tiana , Buss Emily , Calandruccio Lauren , McCreery Ryan , Miller Margaret , Rodriguez Barbara , Leibold Lori
Published: November 2022

Spanish-English bilingual children living in the US often become more proficient in English compared to Spanish over time, in part due to education models. For example, most bilingual children in the Midwest receive educational instruction in English or rapidly transition to English-only instruction. If a bilingual child’s relative proficiency shifts, how does that shift affect their speech recognition? To address this question, we invited participants from the Children’s English and Spanish Speech Recognition Test (ChEgSS) normative study back three years later to retest their speech recognition. The initial study evaluated word recognition in 83 Spanish-English bilingual children with normal hearing. Children completed Spanish and English word recognition tests in speech-shaped noise and two-talker speech using a 4AFC procedure. Language proficiency and language use were assessed using standardized tests and a questionnaire. Results indicated that age and receptive vocabulary influenced word recognition performance. In this study we retested a subgroup of children who were between the ages of 4-8 years in the initial study using the same procedures. Results will advance our understanding of the association between language proficiency and word recognition in this demographic of bilingual children.
Measuring second language acquisition of spanish lenition
Authors: Meyer Rachel , Wayland Ratree , Wang Fenqi
Published: November 2022

In intervocalic position, Spanish /b/, /d/, and /g/ are lenited to fricatives or approximants [β], [ð], and [ɣ] (Hualde 2005).The goal of this study is to examine the ability to learn allophones of these Spanish voiced stops among L2 learners. Eighteen native English-speaking Spanish learners were recorded reading word lists at the beginning and end of a semester-long course on Spanish pronunciation, which included explicit instruction on voiced stop allophones. Ennever, Meakins, and Round (2017)’s automatic segmentation method was used to analyze degree of lenition. This method uses the intensity contour to determine the on- and offset of intervocalic consonants. It yields three measurements: difference between maximum and minimum intensity (Δi), maximum change in intensity over time, i.e. velocity, (vpeak) and duration. A smaller absolute value of Δi and vpeak, and a shorter duration correspond with a greater degree of lenition. Between the two recording times, Δi, vpeak, and duration all decreased, demonstrating some learning of Spanish lenition. Results on the impact of preceding and following vowels, and consonant place of articulation were mixed. Syllable stress and age of onset of Spanish instruction had no effect on lenition.
Linguistic transfer of voice onset time: Aspiration and voicing
Authors: Chuang Jarry C.
Published: November 2022

Crosslinguistic comparison of VOT has indicated linguistic transfer of voicing and aspiration contrasts in many languages. Mandarin has clear aspiration contrasts for voiceless stops, while Min presents another complicated VOT pattern, where voicing and aspiration contrasts are involved. The present study makes a crosslinguistic comparison between languages with voicing and aspiration contrasts as well as the potential linguistic transfer of VOT in English contexts from Mandarin and Min. There are three subject groups, including American English natives and Mandarin-Min bilinguals with different levels of Min-fluency. Mandarin-Min bilinguals have more aspirations for aspirated voiceless stops than English natives. They also present two surfaces for English underlying voiced stops, voiced and unaspirated voiceless. Different levels of Min fluency are found to influence the tendencies towards voiced or unaspirated voiceless representations of English voiced stops. The overall finding presents a clear crosslinguistic influence on VOT patterns.
Phonological learning of American English: An acoustic study of Flapping in Mandarin-speaking EFL Contexts
Authors: Chuang Jarry C.
Published: November 2022

The study explores the nature of non-native flapping under Mandarin-speaking EFL contexts. Flapping as a dominant feature in American English (AE) offers an indicative insight into phonological learning. Forty college students were asked to read words and sentences with intervocalic flapping potentially produced. (Non-)English major students (ENGs/non-ENGs) were respectively invited to make distinctions on the impact of language exposure on crosslinguistic flapping production. Acoustics results have examined and showed that ENGs had a higher frequency to produce [è¾] than non-ENGs might. While more flapping was produced, ENGs possibly make erroneous phones [d]. It has been interpreted as the results of phonetic upward convergence and hypercorrection, where [ɾ] for /t/ can be produced as [d] for the similar quality and the same voicing they share. It is also found that female subjects had more flapped sound [ɾ] in production than males do. Generally, acoustic findings demonstrate that flapping is achievable phonological processing in non-English native contexts. More exposure to English and linguistic training can potentially acoustically trigger a higher occurrence of flapping in production (, while It remains uncertain whether flapping could be articulatorily transferred).
In-sensor signal processing techniques for Lamb waves inspections
Authors: De Marchi Luca , Mohammadgholiha Masoud
Published: November 2022

Structural health monitoring based on guided waves (GW) is typically performed by controlling a large number of piezoelectric transducers placed on the component to be inspected. The permanent installation of this technology allows to acquire information about the structural integrity on demand, but it has several limiting factors: bulky hardware instrumentation and large number of connecting cables, complex signal processing, high power consumption and, consequently, high integration costs. Such limitations hamper the adoption of the GW technology in application domains with stringent weight requirements (e.g., aerospace and automotive).These limitations can be addressed by adopting transducers with inherent beam steering capabilities. Such capabilities can be achieved by properly shaping the electrodes of the piezotransducers according to the dispersion characteristics of the waveguide to produce anisotropic wavenumber filtering effects. This “In-Sensor” signal processing can be used to selectively generate ultrasonic waves along arbitrary directions depending on the frequency content of a single excitation signal, or to automatically detect the direction of arrival of mechanical waves propagating within the structure with minimal hardware/software requirements. [In this work (supported by the Horizon2020 project GW4SHM), numerical and experimental validations of this concept will be presented, together with possible future developments.]
Performance of a Bayes factor (BF) based broadband active acoustic system
Authors: Ferreira Ryan , Gendron Paul J. , Lopes Daniel
Published: November 2022

We explore the performance of a Bayes Factor (BF) active acoustic inference approach under various refraction and rough surface scattering regimes that typify diverse ocean waveguides. The BF processor, a time varying quadratic form over beam-angle observations, enables various user risk minimization strategies. The nature of the BF quadratic form is shaped by the expected ambient noise, reverberation and target angle-delay spectra. The structure of the BF processor provides intuition regarding the role of prior environmental and bathymetric information on detection in shallow water ocean waveguides with rough boundary scattering. The distribution of the BF under the composite null hypothesis when target and reverberation are well approximated as uncorrelated is shown to be a superposition of heteroskedastic gamma densities with the degree of freedom being the dimension of the target hypothesis scattering sub space. The distribution of the BF under the composite alternative is a superposition of heteroskedastic scaled non-central chi-square distributions. These distributions do not admit simple closed forms but can be well approximated. We consider a number of refractive and scattering regimes and relate the probability of detection as a function of probability of false alarm under conventional fixed threshold and cost rules. [This work supported by the Office of Naval Research.]
Office of Naval Research Undersea Signal Processing, Contributions of Dr. Lisa Zurk
Authors: Davidson Keith L.
Published: November 2022

The Undersea Signal Processing team at the Office of Naval Research (ONR 321US) is tasked with developing advanced active/passive sonar signal and information processing technologies that improve the anti-submarine warfare (ASW) performance of US Navy sonar systems. Pursuant to this goal ONR supports academics whose research, being on the cutting edge, lead to high-risk technologies with potential for the greatest advancement of fleet capability. Dr. Lisa Zurk was such an academic, first supported by ONR 321US in 2005. Dr. Zurk’s research focused on developing signal and information processing algorithms which exploited the physics of the underwater operating environment. She believed the path to significant gains in sonar system performance would be obtained through exploitation of environmental knowledge. This belief is now a realization within the Naval Research Enterprise (NRE) and was a primary motivation for initiation of the ONR Task Force Ocean (TFO) Program in 2017. From establishment of the NEAR-Lab at Portland State University in 2005 until her transition to a Program Manager at the Defense Advanced Research Projects Agency in 2016, Dr. Zurk made significant contributions to the NRE. This presentation looks to highlight these past contributions and to consider their present impact.
Case study of a Brothertown Indian Nation cultural heritage siteToward a framework for acoustics heritage research in simulation, analysis, and auralization
Authors: Hsu Timothy , Wenger Seth , Leonard Hope
Published: November 2022

The Brothertown Indian Nation and their ancestors have a centuries old heritage of group singing beginning along the Northeast Atlantic coast of what is now the United States and following them along their migration to the Midwest. The 18th century Curricomp cabin still stands in Connecticut and was an important location in the singing history and political movement that built Brothertown (Eeyamquittoowauconnuck). In this paper, a collaboration with Brothertown Indian Nation and an ongoing public humanities project regarding the Tribe’s aural traditions, a case study will be presented that investigates (1) the results of acoustic modeling and simulation of the Curricomp cabin and (2) auralizations for both binaural listening and a spatial audio installation using those models. Significantly, this paper employs a novel theoretical framework for acoustic heritage research that allows for (3) an analysis of how the scientific process and technological practices mediate intangible heritage. The acoustic models and auralization techniques created in this case study provide acoustic access to a heritage location that would otherwise be inaccessible to the Brothertown Community. The auralizations used in the spatial audio installation serve as a public humanities tool to amplify the contemporary voice of the Brothertown Indian Nation.
Virtual acoustic reconstruction of the Roman amphitheater of Avella in Italy
Authors: Berardi Umberto , Iannace Gino , Trematerra Amelia , Bevilacqua Antonella
Published: November 2022

In ancient Rome, gladiator fights were very popular. The places where these shows took place were called amphitheaters, due to the particular shape of the elliptical building. Amphitheaters were widespread, and in each city, one or more of these buildings was present. This paper describes the virtual reconstruction of the acoustics of the amphitheater Avella, close to Naples, Italy. This amphitheater was discovered a few decades ago and was only partially rebuilt. Today, it is used for musical performances during the summer season mainly. The plan of the building is elliptical, and the dimensions of the arena are 35 m for the minor axis and 65 m for the major axis. Acoustic measurements were performed in the current state with an impulsive sound source and the acoustic parameters were obtained according to the ISO 3382 standard. Subsequently, from the dimensions of the current state and in analogy with the architecture of other amphitheaters existing today, a virtual reconstruction of the original shape was performed. The virtual model was developed with the architectural acoustics software Ramsete in order to obtain the acoustic characteristics of the amphitheater as it was in Roman times. In particular, the spatial distribution of the acoustic characteristics on the steps where the audience was seated is described and discussed.
Urban habitats and noise impact avian communities and shape vocal mimicry in a songbird
Authors: Moseley Dana , Tolchin Jaclyn
Published: November 2022

Urban landscapes present problems for wildlife including highly modified habitat, anthropogenic noise pollution, and competition for suitable habitat. These novel selection pressures filter species present in urban habitats or result in changes to behavior. Recent studies show that some bird species sing differently in noisier, urban areas compared to rural areas, and that anthropogenic noise alone can exclude species. We investigated how the level of urbanization affects (1) bird species composition detected acoustically, and (2) the assemblage of species that a songbird mimics from the local bird community. We studied gray catbirds, Dumetella carolinensis, across an urban gradient (Washington, DC to Virginia) and predicted catbirds in urban habitats would mimic fewer species or mimic more urban-adapted species. The results showed avian community composition differed along the urban gradient and was best predicted by impervious surface and noise level. The species composition of catbird mimicry was predicted by site soundscape, indicating catbird mimicry reflects the local avian community. Since urbanization level was found to significantly predict avian community composition, these findings support the hypothesis that urbanization impacts catbird song by influencing the community of sounds available for catbirds to mimic. Catbirds living in habitats of varying levels of urbanization have significantly different songs from catbirds in other habitats, due to their surrounding bird communities and noise levels differing.
Observation of a golden cheeked warbler (Setophaga chrysoparia), utilizing a typical B-song but an atypical A-song
Authors: Knobles David P. , Hutchinson Darrell , Wilson Preston S. , O'Donnell Lisa
Published: November 2022

From 27 March through 2 June 2017, a golden cheeked warbler (Setophaga chrysoparia), code named “Piccolo,” claimed a territory within the Balcones Canyonland Preserve near Austin, Texas and sang a combination of atypical A-songs combined with typical B-songs. To the authors’ knowledge, this A-song variant has not been previously reported. In situ observations of Piccolo’s movements were used to determine the extent of Piccolo’s defended territory. In addition, between 14 April and 7 June, an acoustic recorder was deployed in the territory to record the variant song along with the soundscape. On April 28, a second-year competitor male entered Piccolo’s territory and intense and prolonged counter-singing was recorded through May 24. The competitor produced typical A- and B-songs while Piccolo counter-sang in the aforementioned variant A-songs and typical B-songs. During the recording period, Piccolo did not vocalize any typical A-songs. Two additional competitor males that used typical B-songs were also observed and recorded. The in situ observations and acoustic analysis of Piccolo’s atypical countersigning were compared to typical interactions between other nearby birds to ascertain whether the variant song provided an advantage or disadvantage for Piccolo. [Work supported by the City of Austin.]
The impact of the central opening on nonlinear effects in ultrasound fields generated by Sonalleve V1 and V2 MR-HIFU systems
Authors: Karzova Maria M. , Kreider Wayne , Partanen Ari , Khokhlova Tatiana D. , Sapozhnikov Oleg A. , Yuldashev Petr V. , Khokhlova Vera A.
Published: November 2022

Previous studies have shown that the Sonalleve MR-HIFU clinical system can generate shocks of 80–105 MPa at the focus, which is sufficient for boiling histotripsy. Two versions of the system (V1 and V2) have therapeutic transducers that differ in focusing angle, arrangement of elements, and the size of a central opening. The goal here was to reveal the impact of different array geometries on shock amplitudes at the focus. Nonlinear modeling of the array’s field in water using boundary conditions reconstructed from holography shows that at the same power output, the V2 array generates 10–15 MPa lower shock amplitudes at the focus. Although this difference is mainly caused by the smaller focusing angle of the V2 array, the larger central opening of the V2 array has a nontrivial impact. By suppressing a direct wave, the central opening produces a somewhat higher shock amplitude. Axisymmetric equivalent source models were constructed for both arrays and the importance of including the central opening was demonstrated. These models can be used in the “HIFU beam” software for simulating nonlinear fields of the Sonalleve V1 and V2 systems in water and flat-layered biological tissues. [Work supported by RSF-22-72-00047 and NIH R01EB025187.]
Palpating particles using the acoustic radiation force: A new approach to magnetic particle imaging
Authors: Zarcone Kristen , Caskey Charles F. , Grissom Will
Published: November 2022

Magnetic particle imaging (MPI) is a tracer-based imaging technique that does not require radiation or a cyclotron. However, it does require bulky MRI-like hardware and does not produce a background tissue image. We propose a new approach to MPI that uses the acoustic radiation force to dynamically move iron nanoparticles through a magnetic field gradient, thereby changing their magnetic moment and producing a detectable signal in a receiver coil. An image could be formed by electronically steering the ultrasound focus to push particles at different spatial locations, like an ultrasonic palpation. This would enable a device that attaches to an ultrasound imaging transducer for simultaneous MPI and inherently registered ultrasound imaging. To test the feasibility of the technique, a cylindrical agar and graphite phantom was placed between a Maxwell coil pair which generated a linear field gradient across it, and particle signals were detected using a receiver solenoid. 2-ms ultrasound pulses were applied using a 6 MHz transducer to generate displacements along the magnetic field gradient. Signal measurements confirmed a lack of signal when iron nanoparticles were absent from the phantom, but the signal was detected when particles were present, with amplitudes that linearly increased with the gradient coil current.
Characterizing the steering performance of a diagnostic-therapeutic ultrasound array using measured and synthesized holograms
Authors: Williams Randall P. , Kreider Wayne , Nartov Fedor A. , Khokhlova Tatiana D. , Karzova Maria M. , Yuldashev Petr V. , Khokhlova Vera A. , Sapozhnikov Oleg A.
Published: November 2022

Acoustic holography is frequently used for the characterization of fields generated by ultrasound transducers. For arrays with electronic focusing and beam steering, separate holograms are needed to represent the 3D field for each combination of array parameters. In this paper, we show that holograms for the field generated by each individual element in an ultrasound array can be recorded in a single hydrophone scan, by interleaving a series of excitations at each measurement location in which each element is driven separately. Such holograms were recorded for a 64-element diagnostic-therapeutic linear array with a nominal focal length of 50 mm and pitch of 0.8 mm, which is smaller than the wavelength at the operating frequency of 1.05 MHz. The resulting holograms reveal aspects of crosstalk and variations between array elements. By summing the elemental holograms with the appropriate phase shifts, holograms are synthesized representing source conditions for cases where the entire array is used to generate different beam configurations, with focal lengths between 35 mm and 60 mm, and steering angles of up to 20°. These synthetic holograms are shown to accurately characterize non-ideal steering behavior of the transducer, confirmed through direct hydrophone measurements. [Work supported by NIH grants R01EB023910 and R01EB025187.]
Ultrasonic characterization of distributed cracking damage in concrete using multiply scattered wave fields
Authors: Popovics John , Song Homin , Feldman Steven
Published: November 2022

This paper reports work to detect, visualize, and characterize alkali–silica reactivity cracking damage in concrete using multiply scattered ultrasonic wave fields. Numerical simulations and laboratory-scale experiments are performed to understand ultrasonic surface wave scattering caused by distributed cracks in concrete, distinguishing that caused by the internal aggregate network. The simulations and experimental results reveal that incident ultrasonic surface waves undergo complicated multiple scattering set up by distributed cracks. To extract the crack-induced multiply scattered ultrasonic wave fields, a frequency-wavenumber (f-k) domain signal filtering approach is proposed. The feasibility of the signal analysis approach is then established by a series of experiments on large steel reinforced concrete blocks with known and controlled cracking damage. The experimental results demonstrate that distributed cracks can be detected and visualized using the proposed ultrasonic signal analysis approach, even at very early stages of the damage process. In addition, we demonstrate that the progress of damage over time can be monitored, where the cracking damage extent is closely related to the extracted multiply scattered wave field energy.
Effect of bone degradation on axially transmitted low frequency (<500 kHz) ultrasonic guided waves
Authors: Chaboty Aubin A. , Nguyen Vu-Hieu , Naili Salah , Haiat Guillaume , Bélanger Pierre
Published: November 2022

The early diagnosis of osteoporosis through bone quality assessment has been extensively studied in the past few years. Research in axial transmission in long cortical bone using ultrasonic guided waves was shown to be sensitive to variations of the bone properties such as the geometry and the mechanical properties. The aim of this presentation is, therefore, to simulate a complex bone-like geometry using 3D finite elements (FE) in order to investigate the influence of the cortical thickness mechanical properties degradation. Three parameters were investigated: (1) the thickness of the periosteal region, (2) the degradation of the endosteal region, and (3) the position of the transition zone from periosteal to endosteal regions. Moreover, the influence of soft tissue was investigated on a plate-like structure using semi-analytical iso-geometric analysis method (SAIGA). Two cortical bone phantom plates with different mechanical properties covered with a soft tissue mimicking material were used to perform axial transmission measurement. The dispersion curves of the propagating modes were experimentally measured and then were compared to the solutions obtained with the SAIGA method. The results showed the possibility to retrieve the properties of the bone phantom plates through an inversion of the dispersion curves.
Laser shock wave propagation in a 3D woven composite material
Authors: Cuenca Eduardo , Ducousso Mathieu , Berthe Laurent , Coulouvrat Francois
Published: November 2022

We investigate the propagation of a laser shock wave within a composite material used in aeronautics. This one is made of carbon fibers woven according to a 3D pattern within an epoxy matrix. The shock wave is generated by an impulsive (of order 10 ns) laser beam of power a few GW/cm², focused on the surface of a metallic layer attached to the composite. The metallic surface ablation results in an expanding plasma inducing a shock wave in the material with a peak stress of a few GPa. Its propagation can be measured by the velocity of the opposite surface of the sample detected by laser interferometry. The high frequency content of the signal and the heterogeneous and anisotropic behavior of the material induce a complex propagation. A measurement campaign has been performed for different samples. A 2D numerical model has been developed based on a finite difference discretisation of equations of linear elastodynamics for the propagation part, combined with a nonlinear model of the source. Sample geometry and fiber orientations are obtained from analysis of the images of transversal cuts of the samples. Experimental data are statistically compared to the model and discussed.
Ultrasonic characterization of the microstructure for cold sintered sodium molybdate
Authors: Wheatley Christopher , Mena-Garcia Javier , Randall Clive , Arguelles Andrea P.
Published: November 2022

The Cold Sintering Process (CSP) is a novel manufacturing process that can create high-density metals, ceramics, and composite materials at significantly lower temperatures than conventional sintering. However, the microstructure of cold sintered materials can be more flawed and inhomogeneous than observed in conventionally sintered counterparts. Therefore, more information about the underlying densification mechanisms is required to reduce these flaws and promote CSP as an alternative industrial process. Ultrasonic testing provides a non-destructive approach to analyze the microstructure of these cold-sintered materials. In this presentation, longitudinal attenuation and wave speed are used to characterize sodium molybdate (Na2Mo2O7), a dielectric material. The concentration of inhomogeneities in the microstructure is found to increase proportionally to the heating rate, and with a larger thickness relative to diameter ratio. The densification is ultimately dependent on balancing the kinetics of the transient liquid phase as it undergoes pressure-solution precipitation and evaporation. Finally, the processing parameters are adjusted using information from ultrasonic characterization to optimize for a homogeneous microstructure, showing CSP as a promising lower energy alternative for sintered materials.