bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting return to racing after repair of fractures of the metacarpal/metatarsal condyles in Thoroughbred racehorses
Authors: Young Natalie , Corletto Federico , Wright Ian
Published: May 2022

Objective

To identify prognostic factors for return to racing after lag screw repair of condylar fractures and develop a predictive model for return to racing.

Study design

Retrospective cohort study.

Animals

A total of 356 horses referred to a single referral hospital in the UK with a third metacarpal/metatarsal condylar fracture between January 1999 and December 2018.

Methods

Age, sex, fracture site, fracture characteristics, surgery related variables and complications were retrieved from case records. Data were divided into two sets for model training and model validation. Univariable analyses were performed, and predictors were selected in a stepwise fashion for inclusion in the multivariable logistic regression model. Sensitivity and specificity were evaluated using the second dataset.

Results

Older horses, fillies, fractures of forelimbs, complex, complete, displaced or propagating fractures and concurrent proximal sesamoid bone fracture were negatively associated with return to racing. Colts and geldings were 3 and 4 times more likely to race than fillies, respectively. Horses with hindlimb, incomplete or nonpropagating fractures were 4, 5 and 4 times more likely to race than those with a forelimb, complete or propagating fracture, respectively. Using a predicted probability cut‐off threshold of 0.5, a predictive model was created within one dataset (sensitivity = 84%, specificity = 50.5%) and applied to another (sensitivity = 83.1%, specificity = 24.0%).

Conclusion

Negative prognostic factors were identified and led to a predictive model with acceptable sensitivity and specificity in the tested population.

Clinical significance

The results provide proof of concept for the model in the reported population and justify further validation in different populations of horses.
Effects of Material Properties on Micro-Scale Cutting of TA15 Alloy and Network-Structured TiBw/TA15 Composites
Authors: Yang Minghui , Deng Ben , Peng Fangyu , Rong Yan , Huang Yu
Published: May 2022

Currently, it still lacks the controlled studies which compare differences in the machinability between the TA15 alloy and network-structured TiBw/TA15 composites, which is not conducive to promoting the design and practical application of the TiBw/TA15 composites. Therefore, in this paper, the impact of material properties on the micro-scale cutting performances of the two materials is explored through the in-situ high-speed imaging and digital image correlation (DIC) technique. During the investigation, the chip formation process is recorded under diverse cutting load conditions, and the thermoplastic deformation in the shear plane is quantified using successive images and analyzed based on the microstructural and mechanical properties. Furthermore, the microstructural deformations in the machined subsurface are observed and evaluated for the two materials. The results indicate that the inhomogeneous deformation in micro-scale cutting that inevitably occurs in the TA15 alloy is improved in the TiBw/TA15 composites. And in comparison to the TA15 alloy, the TiBw/TA15 composites have greater temperatures and smaller accumulative plastic strain at failure in the shear plane due to the influences of macro- and micromechanical properties, while the comparison of equivalent strain rates between the two materials depends on the chip type of TA15 alloy. Accordingly, the subsurface deformation of the TA15 ally is notably anisotropic, while the microcracks and voids induced by TiBw reinforcement damage are evident in TiBw/TA15 composites. These findings can provide new insights into the future simulation and prediction of micro-cutting multiphase materials.
Numerical spatial impulse response calculations for a circular piston radiating in a lossy medium
Authors: Murray Drew A. , McGough Robert J.
Published: May 2022

Exact analytical expressions for the spatial impulse response are available for certain transducer geometries. These exact expressions for the spatial impulse response, which are only available for lossless media, analytically evaluate the Rayleigh integral to describe the effect of diffraction in the time domain. To extend the concept of the spatial impulse response by including the effect of power law attenuation in a lossy medium, time-domain Green's functions for the Power Law Wave Equation, which are expressed in terms of stable probability density functions, are computed numerically and superposed. Numerical validations demonstrate that the lossy spatial impulse for a circular piston converges to the analytical lossless spatial impulse response as the value of the attenuation constant grows small. The lossy spatial impulse response is then evaluated in different spatial locations for four specific values of the power law exponent using several different values for the attenuation constant. As the attenuation constant or the distance from the source increases, the amplitude decreases while an increase in temporal broadening is observed. The sharp edges that appear in the time-limited lossless impulse response are replaced by increasingly smooth curves in the lossy impulse response, which decays slowly as a function of time.
Histotripsy bubble dynamics in tendon and anisotropic gel phantoms
Authors: Elliott Jacob C. , Arguelles Andrea , Simon Julianna
Published: May 2022

Collagenous, anisotropic tissues such as tendon have demonstrated resistance to liquefaction by histotripsy, despite the creation, oscillation, and collapse of bubbles verified using B-mode imaging. The objective of this work is to evaluate effects of anisotropy on bubble dynamics in tissue-mimicking hydrogels and compare to anisotropic tissues. Polyacrylamide, fibrin, and collagen hydrogels were fabricated; ex vivo bovine tendons were obtained. Sound speeds were measured in each axial direction to evaluate degree of anisotropy. Hydrogels and tendons were exposed to 1.5-MHz focused ultrasound with 10-ms pulses repeated at 1-Hz with p + =89 MPa, p− = 26 MPa. Cavitation activity was monitored with simultaneous high-speed photography and passive cavitation imaging using a Philips/ATL L7-4 transducer and Vantage® ultrasound system. Violent cavitation activity and fractionation was observed in polyacrylamide, collagen, and fibrin hydrogels with low degrees of anisotropy (<1.2); such behavior is unlike that of tendon. Dehydration of fibrin gels resulted in a 55% reduction in peak cavitation emission energy and a 260% increase in anisotropy compared to standard fibrin formulations. These gels demonstrated similar cavitation energy than tendon (within 4%) but 50% less anisotropy, indicating more hydrogel formulations should be explored to better mimic collagenous, anisotropic tissue. [Work supported by NIH R21EB027886.]
The effect of surface tension on the color Doppler ultrasound twinkling artifact
Authors: Rokni Eric , Simon Julianna C.
Published: May 2022

Imaging crystalline structures with Doppler ultrasound can produce a rapid color shift, termed the twinkling artifact, that can assist in diagnosing pathological mineralizations such as kidney stones, heterotopic ossification, gout, and breast microcalcifications. Twinkling is theorized to arise from scattering off surface crevice microbubbles, which are affected by the surface tension between the bubble and surrounding medium. In this study, we evaluated the effect of surface tension on twinkling in pure crystals. Cholesterol, calcium phosphate, and uric acid crystals were grown in vitro (n = 5 each) and imaged with a Philips/ATL L7-4 transducer and Vantage-128 research ultrasound system. Crystals were imaged in water while varying surfactant concentration (0%–4%) leading to surface tensions that ranged from 45–72 mN/m. Surface tension of the solution was determined by measuring the contact angle of 0.1-mL droplet on an acrylic sheet exposed to air. As the concentration of surfactant increased, twinkling was found to decrease by ∼20% for cholesterol and calcium phosphate and ∼10% for uric acid. These results continue to support the crevice bubble theory of twinkling and suggest the importance of surface tension when evaluating minerals with the twinkling artifact. [Work supported by NSF-CAREER-1943937 and NSF-GRFP-DGE1255832.]
The use of real-time passive cavitation imaging for monitoring boiling histotripsy treatments
Authors: Thomas Gilles P. , Peek Alex T. , Khokhlova Tatiana D. , Khokhlova Vera A.
Published: May 2022

Boiling histotripsy (BH) is a high intensity focused ultrasound method that induces mechanical tissue liquefaction and relies on the formation of a mm-sized vapor bubble at the focus. One challenge of transcutaneous BH is to confirm the presence of such bubble and to differentiate it from prefocal cavitation. Strong prefocal cavitation can shield the focus, prevent initiation of boiling, and lead to unsuccessful treatment, although an echogenic region would still be present on B-mode ultrasound images. Here, a methodology for real-time monitoring of different bubble activity during BH treatment is proposed. Custom BH systems of 1 and 1.5 MHz with inline ultrasound imaging probes connected to a Verasonics V1 system were used for BH treatments in pigs in vivo and in ex vivo tissues. Backscattered signals arriving to the imaging probe were recorded during the 10 ms BH pulses delivered at 1 Hz and passive cavitation imaging (PCI) reconstruction was performed and displayed on top of the B-mode images to identify and classify the regions of bubble activity. Spectral analysis of the PCI signals promoting prefocal cavitation and lack thereof was performed to identify the spectral features corresponding to prefocal cavitation and vapor bubble formation. [Work supported by NIH R01EB007643, R01GM122859, and R01EB25187.]
“Acoustics” as a “system”—A refreshed narrative leading change in standards, codes, and guidelines
Authors: Koukounian Viken
Published: May 2022

Although “acoustics” is widely understood to be in relation to the person, it is—more correctly—a branch of physics that studies the behavior of mechanical energy in media. In contrast, “psychoacoustics” concerns itself with the perception (or psychology) of sound and the associated physiological effects. The disassociation is best exemplified by traditional architectural acoustical design schemes—i.e., “acceptable-level” and “categorization”—which are prevalent throughout existing Standards, Codes, and Guidelines. The result, as evidenced by the meta-analysis of modern and sustainable best practices by a group at Harvard, is an Indoor Environment Quality parameter that does not consistently score better, and in several studies, results in lower satisfaction scores with noise. This presentation presents posteriori—correlations between “occupant satisfaction” and “acoustical satisfaction,” “acoustical satisfaction” and “acoustical privacy,” and “acoustical privacy” and “health and well-being”—to justify the pitfalls of traditional strategies, and to develop a priori—a framework for “good acoustics.” This refreshed narrative, to consider acoustics as a system, leads change among the most popular sustainability and well-being Standards, such as WELL, Green Globes, and LEED. This presentation endeavors to summarize notable updates and to identify new risks and challenges associated with recent versions of the aforementioned documents.
Thwarted by data, saved by fundamentals
Authors: Hoover K. Anthony , L'Italien Zachery O. , Ashburn Henry
Published: May 2022

The overwhelming majority of acoustic data that are available to most architectural design professionals is in abbreviated single-number ratings, without details or full test reports. Omitted key details can greatly affect the actual performance. Despite best intentions to satisfy codes and criteria, most of these designers do not adequately understand the acoustic fundamentals to recognize and then avoid significant problems and under-designed projects. Examples of problems with data regarding sound isolation, HVAC noise, and sound-absorption will be discussed, along with suggestions toward better understanding and more desirable/reliable end results.
Floor covering standards based on improvement of impact insulation ratings
Authors: Dong Wayland , Lo Verde John
Published: May 2022

A common acoustical design task is predicting the impact rating of an existing floor system that is modified by adding or changing flooring elements. Most codes and regulations are based on impact testing of the resultant system. It might seem that floor coverings could instead be specified using laboratory testing of the improvement in impact sound insulation of floor coverings (ΔIIC test) per ASTM E2179. However, in practice the ΔIIC rating does not accurately predict the resultant assembly. Here, we investigate several avenues that may allow improved prediction of impact ratings. The first path is modification the ΔIIC rating by removing the rule limiting the deficiency in any third-octave band to 8 dB (“the 8 dB rule”). The 8 dB rule has been shown to result in a 4-point bias of the ΔIIC rating, which may account for a large portion of the inaccuracy. A second path is using the high-frequency impact rating, ΔHIIC instead of ΔIIC, which is promising since flooring improvements are largely limited to the high-frequency range. A third path is defining a standard lightweight (i.e., wood-framed) reference floor to complement the existing concrete reference floor. These investigation may yield impact requirements for flooring that are easier to understand, specify, and verify.
Application of acoustical control through building codes and regulatory requirements
Authors: Rawlings Samantha , Lo Verde John , Dong Wayland
Published: May 2022

The International Building Code (IBC) establishes minimum acoustical performance requirements for permanent and transient housing facilities. The lab parameters for acoustical performance within the IBC are useful during the design and permitting process but fail to provide code officials, builders, designers, and residents a method for evaluating the success of a completed building. The latest update to the IBC in 2021 establishes standards and metrics for use in evaluating post-construction code compliance to mutually protect all stakeholders (builders, code officials, occupants, municipalities, etc.) in housing facilities and reduces historic ambiguity in the code. Historically, the nature of the metrics and their ability to evaluate success has been limited (“Field impact insulation testing: Inadequacy of existing normalization methods and proposal for new ratings analogous to those for airborne noise reduction,” LoVerde/Dong, JASA, 2005). There is some historic precedent regarding the application and measurement requirement for field metrics (“Coping with uncertainties in the design and evaluation ofacoustical assemblies,” LoVerde/Dong, ASA Hong Kong, 2012). This presentation expands this conversation to examine regulatory requirements and discusses application of field verification of acoustical performance metrics.
Acoustic array signal processing with the Stockwell transform
Authors: Collar Steven , Frazier Garth
Published: May 2022

The Stockwell transform is a wavelet-like transformation based on a Fourier kernel weighted by a symmetric, frequency-scaled, time-shifted window function. Thus, it is suitable for analysis of non-stationary waveforms and transients in particular. In its discrete-time, orthogonal basis realization known as the discrete orthogonal Stockwell transform (DOST), it is possible to transform an N-point sequence in O(N log N) operations. In this presentation, we show how to perform direction-of-arrival and transient waveform estimation in the Stockwell basis in a manner that is similar to traditional multi-channel frequency-domain (discrete Fourier transform) techniques. This enhances detection of multiple transients within the same data frame sequence.
Improvements of the Stevens drone acoustic detection system
Authors: Kadyrov Daniel , Sedunov Alexander , Sedunov Nikolay , Sutin Alexander , Salloum Hady , Tsyuryupa Sergey
Published: May 2022

Stevens Institute of Technology (SIT) designed and built multiple acoustic sensors to detect and track drones using Steered-Response Phase Transform (SRP-PHAT) and classify them using narrow-band frequencies. SIT improved a previously built four-microphone system by increasing the number of microphones to seven, modifying the software, and improving the testing algorithm for system performance estimation. The four- and the seven-microphone systems were deployed during several tests conducted with multi-rotor UAVs of different sizes, including the DJI Inspire 2, DJI Mavic 2 Pro, Autel Robotics EVO II Pro, and the Intel Falcon 8 performing flight patterns at various distances, elevations, and speeds. The tests were conducted in an environment with low-flying aircraft and vehicular traffic noise. Acoustic signatures were collected and detection distances were compared for the tested UAVs. The improved seven-microphone system provided farther detection and classification distances than the previous four-microphone system. Typical detection distances were between 300 and 500 m with a bearing accuracy within five degrees. An analysis of the effect of external noise on performance was also performed.
3D noise modeling of an urban environment: Simulated and measured noise characteristics of the University of the District of Columbia campus
Authors: Mandjoupa Lirane , Davis Dorian , Gaye Samba , Mohamed Shehabaldin , Etochukwu Etochukwu , Mahmoud Wagdy , Wan Lei , Denis Max
Published: May 2022

In this work, a 3-D numerical method is employed to predict the noise propagation within the University of the District of Columbia (UDC). UDC is located within an urban environment in Washington, DC. Sound pressure level measurements of various noise sources including traffic noise are obtained. Of particular interest is the method’s ability to accurately simulate the urban space. Accuracy is evaluated comparatively between simulated and measured results of acoustic parameters in the mid- to high-frequency regimes. Specifically, reverberation time, energy decay time, and sound pressure level. The results and limitations of the particle-tracing method for predicting sound propagation in urban environments are discussed.
Sonochemical synthesis of electrocatalysts for low-temperature water electrolysers
Authors: Pollet Bruno G. , Hansen Henrik E. , Sunde Svein , Burheim Odne S. , Seland Frode
Published: May 2022

An important step in the process of producing hydrogen a viable method is to improve the efficiency and reduce the cost of low-temperature water electrolysers. One of the most crucial components is the catalyst used to drive the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Traditionally, the nanosized electrocatalysts are synthesized through a chemical reduction method involving a strong reducing agent like sodium borohydride, polyol, etc. Being able to control the nucleation and growth and therefore the size of the nanocatalysts, however, is not straightforward with the chemical reduction method where the use of surfactants is heavily relied upon, thus complicating the method for the industry. An alternative synthesis route involves the in-situ generation of radicals to serve as reducing agents through high power ultrasound (20 kHz–1 MHz) in a process where water is split into OH- and H-radicals referred to as water sonolysis. This presentation highlights the effects of ultrasonication frequencies, ultrasonication, times, pH solutions, reducing agents, and different saturation gasses on the generation of metallic nanoparticles and their subsequent electrocatalytic activities towards the HER and OER in mild acidic and alkaline environments. A series of physical characterizations on these sonochemically prepared nanoelectrocatalysts will be shown and discussed.
Dispersion relation for harmonic generation in nonlinear elastic waves
Authors: Khajehtourian Romik , Hussein Mahmoud I.
Published: May 2022

We present a theory for the dispersion of generated harmonics in a traveling nonlinear wave. The harmonics dispersion relation—derived by the theory—provides direct and exact prediction of the collective harmonics spectrum in the frequency-wavenumber domain and does so without prior knowledge of the spatial-temporal solution. The new relation is applicable to a family of initial wave functions characterized by an initial amplitude and wavenumber. We demonstrate the theory on nonlinear elastic waves in a homogeneous rod and demonstrate its extension to periodic rods. We investigate a thick elastic rod admitting longitudinal motion. In the linear limit, this rod is dispersive due to the effect of lateral inertia. The nonlinearity is introduced through either the stress–strain relation and/or the strain–displacementgradient relation. Using a theory we have developed earlier, we derive an exact general nonlinear dispersion relation for the thick rod. We then derive a special case of this relation and show that it provides an exact prediction of the generated harmonics spectrum, in frequency versus wavenumbers. Both relations are validated by direct time-domain simulations, examining both instantaneous dispersion (by direct observation) for the general nonlinear dispersion relation and short-term, pre-breaking dispersion (by Fourier transformations) for both the general and specialized relation.
Collisions of nonlinear waves in flexible mechanical metamaterials
Authors: Yasuda Hiromi , Shu Hang , Jiao Weijian , Tournat Vincent , Raney Jordan
Published: May 2022

Flexible mechanical metamaterials are compliant structures designed to achieve desired mechanical properties via large deformation or rotation of their components. While their static properties (such as Poisson’s ratio) have been studied extensively, much less work has been done on their dynamic properties, especially nonlinear dynamic properties induced by large movement of internal components. Here, we examine the nonlinear dynamic response arising from impact loading of mechanical materials that consist of 1D and 2D arrangements of rotating squares, which leads to formation of solitons. Permanent magnets are added to the squares, which causes the metamaterial to become multistable. Rotations of the squares can thereby lead to sudden rearrangements of squares into new phases. We experimentally and numerically characterize the collisions of solitons in these flexible mechanical metamaterials, which, depending on their amplitude and chirality, can induce a variety of responses, including phase transitions.
Experimental elastic wave control in a piezoelectric phononic crystal with spatio-temporal modulation of electrical conditions
Authors: Tessier Sarah , Croënne Charles , Allein Florian , Vasseur Jérôme , Dubus Bertrand
Published: May 2022

This work concerns the propagation of elastic waves in a piezoelectric phononic crystal made of several identical piezoelectric elements separated by electrodes. In such a structure, electrical conditions prescribed to the electrodes can be modulated in space and in time and therefore can strongly modify the dispersion curves of the phononic crystal. For example, a periodic grounding of the electrodes introduces a Bragg band gap which does not exist when the electrodes have a floating potential condition [Degraeve et al., J. Appl. Phys. 115, (2014)]. When the electrical conditions of the electrodes are modulated in space and in time, dispersion curves are tilted with respect to the configuration in the reference medium and nonreciprocal wave propagation may occur at some modulation speeds in specific frequency bands [Croënne et al., Appl. Phys. Lett.110, (2017)]. The experimental set-up is based on a stack of 113 piezoelectric rings and 114 electrodes. The spatio-temporal modulation of the electrical conditions is performed using a digital signal processor (DSP) in order to reach high modulation speeds. This modulation is performed by shifting the position of the periodic ground conditions of the electrodes versus time. The experimental dispersion curves are obtained using measurements of the normal displacement of the piezoelectric rings with a scanning laser vibrometer. The evolution of dispersion curves as a function of modulation speed is analyzed and compared to finite element simulation results.
Stress and vowel reduction by Korean Learners of English
Authors: Park Ha Lim
Published: May 2022

Having a foreign accent is unavoidable for late second or foreign language learners. The reason is that physical changes in the brain influence learning a variety of aspects in a new language system (Flege, 1987; Patkowski, 1990). In other words, a well-established first language mediates the acquisition of a second language. The mediation can be called cross-linguistics influence or negative transfer (Sharwood Smith and Kellerma, 1986). In terms of suprasegmental aspects of pronunciation, vowel reduction occurring in stress-timed languages such as English but lacking in syllable-timed languages is noteworthy to understand the cause of nonnative accents. The present work aims to explore patterns of vowel reduction in Korean accented English, with the goal of finding pronunciation issues in the English of Korean learners that might be due to transfer effects from an acoustic-phonetic standpoint. English speech samples from native English and Korean speakers of the Wildcat Corpus were used for data analysis. The vowel qualities, the duration ratios, and formant values of unstressed vowels produced by Korean and English speakers were analyzed. Results show that the Korean speakers tend not to reduce English unstressed vowels, assimilate them into similar vowels in their vowel inventory, and produce them as full vowels.
Evaluating the learnability of vowel categories from infant-directed speech
Authors: Narkar Jahnavi , Khlystova Ekaterina A. , Aly Ann M. , Kim Ji Young , Sundara Megha
Published: May 2022

Hyper-articulated vowels are considered a hallmark of infant-directed Speech (IDS) and are thought to facilitate acquisition. Consistent with this idea, vowels in IDS are reported to be more peripheral than in adult-directed speech (ADS) (e.g., Trainor and Desjardins, 2002; Liu et al., 2005). However, there are also reports that vowels in IDS are more variable (Cristia and Seidl, 2014; Martin et al., 2015). We evaluated the learnability of vowel categories from IDS in two languages—American English, which has a crowded vowel space, and Mexican Spanish, which has fewer vowels. First, we used k-means clustering, an unsupervised learning algorithm, to partition vowels based on spectral and duration measures from conversational IDS. The algorithm was trained on IDS from 5 English speakers (Providence Corpus, Demuth et al., 2006) and 12 Spanish speakers (Aly et al., 2016). The vowel categories extracted from IDS were used to classify ADS vowels from 5 English speakers from the Buckeye corpus and 12 Spanish speakers (Kim and Repiso Puigderlliura, 2021). Next, we switched the training and testing set, by training on ADS, and testing on IDS. If IDS is facilitative, we expect a higher accuracy of vowel classification with training on IDS rather than ADS.
Acoustic analysis of vowel production in children with childhood apraxia of speech
Authors: Swartz Michelle T. , Koenig Laura , Hitchcock Elaine R.
Published: May 2022

Childhood apraxia of speech (CAS) is a complex neurological subtype of speech sound disorder (SSD), involving impaired speech motor planning and programming. Speech characteristics of CAS include difficulty in sequencing speech movements in the absence of muscle weakness resulting in segmental (e.g., vowel/consonant distortions) and suprasegmental (e.g., inappropriate lexical stress) speech deficits. Acoustic analysis offers a robust objective diagnostic measurement of CAS for lexical stress and consonant accuracy/consistency. However, other reported CAS features, such as vowel errors and distortions, have yet to be extensively validated using acoustic analyses. This study will acoustically analyze vowel errors and inconsistencies for corner vowels (/i, u, æ, ɑ/) in children with CAS (aged 8;0 to 15;11) compared to peers with SSD and typical development (TD). Vowel space measures (e.g., vowel space area and formant centralization ratio) and consistency (e.g., vowel cluster distribution) will be assessed in 24 children (CAS = 4, SSD = 10, and TD = 10) across various phonetic contexts (e.g., syllable sequencing between anterior to posterior voiced/voiceless stops of increasing syllable length). It is predicted that children with CAS will demonstrate (1) greater vowel inconsistencies as context complexity increases and (2) a neutralized vowel space based on the corner vowels relative to children with SSD and TD.
Perceived naturalness of typical disfluent speech and speech of adults who stutter
Authors: Kampf Ksenia
Published: May 2022

Disfluencies in spontaneous speech have been shown to be sensitive to the syntactic constituency (Levelt, 1989): production is restarted at the boundary nearest to the point of interruption. While there is a production-internal account of constituency structure in the speech of both adults who stutter (AWS) and typical speakers (AWNS), there is no evidence of constituency realization in the perceptional account of disfluent speech. The current study explores whether the constituency structure contributes to the perception of disfluent speech of AWS and AWNS. More specifically, the study investigates whether syntactic constituents are a cohesive unit of perception and whether altering the constituency structure impacts the perceived naturalness of disfluent speech. The participants rated the samples of disfluencies produced by AWS and AWNS for naturalness. The stimuli were presented in their original form as well as in a form with an artificially altered disfluency position. The results indicate that the location of the repetition disfluency is one of the correlates of speech naturalness, both in stuttered and typical speech. At the same time, speech naturalness ratings are minimally influenced by the type of speaker, suggesting that stuttering and typical disfluencies follow similar perceptual patterns.
Word and phrase duration in Mandarin-speaking individuals with Alzheimer’s disease
Authors: Yu Kaiwen , Liu Yadong , Shamei Arian , Gick Bryan
Published: May 2022

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by irreversible cognitive deterioration, often manifesting in pathological speech patterns [Baker et al., Clin. Linguist. Phon. 21(11–12), 859–867 (2007)]. Previous research has examined temporal and acoustic features of AD patients’ speech, including pitch, volume, and voice quality, showing that these measures can be used to discriminate between people with AD and healthy older adults [Meilan et al., Dement. Geriatr. Cogn. Disord. 37(5–6), 327–334 (2014)]. However, whether word and phrase duration are affected by AD remains unclear. The present study measured word and phrase duration from nine Mandarin-speaking AD patients and nine gender-matched neurotypical controls undertaking picture description and naming tasks. Preliminary results show AD patients exhibited a significant difference (t (1688.1) = −5.88, p < .001) in word duration compared to controls, with shorter word duration in the naming task (t (1088.8) = −8.66, p < .001) and longer in the picture description task (t (484.13) = 2.40, p = 0.017); AD patients also uttered significantly shorter phrases than controls in the picture description task (t (86.01) = −2.17, p = 0.033). The preliminary result suggests that AD may affect word and phrase duration. [Work supported by NIH and NSERC].
The Beaufort Sea acoustic duct's variability and its impact on acoustic propagation using the mode interaction parameter
Authors: Kucukosmanoglu Murat , Colosi John A. , Miller Christopher W. , Worcester Peter F. , Dzieciuch Matthew A.
Published: May 2022

The Beaufort duct is a subsurface sound channel formed by cold Pacific Winter Water sandwiched between warmer Pacific Summer Water and Atlantic Water in the Western Arctic Ocean. This duct traps sound waves and allows them to travel long distances without losing energy to lossy interactions with sea ice and surface waves. This study quantifies Beaufort duct variability based on Canada Basin Acoustic Propagation Experiment (CANAPE) and Coordinated Arctic Acoustic Thermometry Experiment (CAATEX) oceanographic observations. Deterministic ocean features induce coupling between acoustic modes confined to the Beaufort duct and non-ducted modes by weakening the duct or causing it to take on an asymmetric form. A non-dimensional mode interaction parameter (MIP) can be defined using the acoustic frequency and the vertical and horizontal scales of sound speed perturbation to characterize coupling strength. It identifies three important wave propagation regimes: sudden approximation, adiabatic approximation, and maximum interaction regime (Colosi and Zinicola-Lapin, 2021). When the MIP between ducted and lossy modes is more and less than 1, strong and weak acoustic variability is predicted, respectively. Variability is high when the MIP between two ducted modes surpasses 1, but modei–mode interference patterns grow more complicated. Acoustic numerical simulations are used to demonstrate various effects.
Environmental characterization from passive acoustic data collected on a partially-spanning array
Authors: Akins Franklin H. , Kuperman William
Published: May 2022

We show that with knowledge of the sound speed along a receiving, partially water-column-spanning vertical line array, mode wavenumber and geoacoustic estimates can be obtained without requiring knowledge of source location or range-rate. This estimation is accomplished simply by applying spatial smoothing and MUSIC to the sample covariance matrix. The method is demonstrated with simulation and subsequently on SWellEx-96 experimental data.
Visualization of tumor angiogenesis using super-resolution ultrasound imaging
Authors: Brown Katherine , Hoyt Kenneth
Published: May 2022

Super-resolution ultrasound imaging (SR-US) is a new technique that breaks the diffraction limit and allows visualization of microvascular structures down to tens of microns. The objective of this presentation is to briefly introduce SR-US imaging and use in various small animal models. Engineering challenges and ongoing opportunities will also be introduced. SR-US is predominantly a software advance that can be integrated with both clinical and preclinical US imaging platforms. After injection of an intravascular microbubble (MB) contrast agent, a time-series of contrast-enhanced ultrasound (CEUS) images are acquired. Spatiotemporal filtering of the CEUS images helps remove the tissue clutter signal and segmentation of the MB signal. Precise localization of the center of each agent is then determined. This process is repeated for each CEUS image in the time series. The resultant SR-US images depict fine microvascular detail typically unresolved using traditional CEUS imaging methods. During this presentation, we will explore use of methods to help improve the MB detection and localization process in space and time like with the use of motion correction and machine learning algorithms. We will also present a series of preclinical examples highlighting the potential of this new technology in cancer research. Results demonstrate that SR-US imaging depicts microvascular structures not visible using traditional CEUS methods. The utility of this new diagnostic tool will play more of a role in theranostics over the next decade.
Super-resolution imaging using conventional and non-conventional beamforming
Authors: Santibanez Francisco , Kierski Thomas , Deruiter Ryan , Jones Rebecca , Soulioti Danai , McCall Jake , Belgharbi Hatim , Crews Davis , Dayton Paul A. , Pinton Gianmarco
Published: May 2022

Super-resolution ultrasound surpasses diffraction limits by localizing spatio-temporally separable contrast agents and generates images that significantly exceed the resolution of conventional B-mode imaging methods. However, the ability to detect contrast agents and to separate their signal from the underlying tissue and from sources of image degradation such as phase aberration or reverberation clutter remains a process that is governed by fundamental wave propagation and beamforming. Here, super-resolution imaging and improvements in contrast detection, imaging depth, resolution, and registration accuracy are demonstrated using conventional and non-conventional beamforming methods in 2D and 3D. Three different imaging schemes: (a) single plane-wave, (b) three steered plane-wave compounding, and (c) 256 focused transmits are compared in vivo to quantify the improvements in contrast detection. Wide-beam 3D transcranial super-resolution and power Doppler images through a human and macaque skull are demonstrated using a 1.5 MHz sparse matrix array. These partially and fully focused methods are also demonstrated transcranially in rodents using 2D imaging at 15 MHz and volumetric imaging at 8 MHz. Finally super-harmonic super-resolution imaging approaches are demonstrated for stationary and moving bubbles in murine tumors. These imaging methods extend the capabilities of super-resolution imaging and may improve the clinical translatability of the technique.
3D finite element modeling techniques and application to underwater target scattering
Authors: Gunderson Aaron
Published: May 2022

Underwater acoustic target scattering measurements rely on high-fidelity modeling for experimental comparison and understanding. Three-dimensional (3D) finite element models are well suited for this purpose, as they can account for arbitrary or unknown target properties and configurations/orientations within complex and asymmetrical seafloor environments. High acoustic frequencies and large physical distances associated with in situ scattering measurements pose challenges to 3D modeling efforts in terms of model sizes and runtimes. Certain model considerations must be made to keep the 3D model computationally efficient, yet accurate in predictive capability. Numerically determined Green’s functions are demonstrated to permit 3D model reduction, while still preserving far-field scattering prediction capability through the Helmholtz–Kirchhoff integral. By determining Green’s functions within the model, they need not be known or estimated for complex ocean environments a priori. Nontraditional scattering formulations and a survey of boundary truncation methods also are explored and implemented for maximal accuracy within small 3D computational domains. Model results for canonical elastic targets within varying seafloor environments are shown and compared to theory and experimentation. [Work supported by the Strategic Environmental Research and Development Program and by the Office of Naval Research, Ocean Acoustics.]
Time-domain simulation of acoustic scattering and internal propagation from multiple gas bubbles
Authors: Hou Jiacheng , Zheng Zhongquan Charlie , Allen John S.
Published: May 2022

Acoustic scattering and resonance responses from multiple gas bubbles are computed using a time-domain simulation based on the numerical solutions of the conservation laws. The time histories of scattered pressure and velocity, both outside and inside the bubbles, are obtained simultaneously from an immersed-boundary method facilitating the investigation of both exterior and interior acoustic fields for non-spherical bubbles. Agreement is found with both analytical scattering solutions and those from empirical shape factors in limiting cases. In addition, the time-domain method allows for the study of the transient acoustic scattering from pulse forcing (Gaussian). In this case, the interior gas oscillates in an off-center, non-uniform manner compared to the steady state forcing cases. The time history and the interior gas behavior are presented in detail for combinations of two bubbles of different sizes and shapes (spherical, prolate, oblate). A comparison and analysis of this immersed-boundary method to the finite element method and boundary element methods is provided. Also, the increasingly important role of computational acoustics in the study scattering of multiple targets of diverse sizes and shapes is highlighted.
Simulation of acoustic liner performance in a grazing flow duct
Authors: Zheng Zhongquan Charlie , Alves Tayanne , Hou Jiacheng , Wu Huixuan
Published: May 2022

Acoustic liners are commonly used to reduce aircraft engine noise. The performance of acoustic liners can be tested in a grazing flow duct. In order to simulate the new extended-reaction liners which allow lateral acoustic propagation inside the liner, finite element methods have been used in the frequency domain computation. In this study, different liner core materials, including honeycomb and foam-metal, are simulated with uniform or varied material properties and geometries. Frequency responses of liners are studied with different materials under several flow conditions. An immersed-boundary, time-domain simulation is also implemented to simulate the broad-band behavior of the liners and to compare with the frequency-domain computation. Optimized material properties and liner arrangement for noise reduction will be investigated.
Enhancing acoustical design using parametric optimization of surface geometries
Authors: Koziczinski Benjamin C. , Nieto Ivan C. , Stegmaier Karlheinz
Published: May 2022

Raytracing is commonly used to design surface geometries. To optimize this process, we propose combining a parametric design approach with an evolutionary solver. These optimization principles are widely implemented across engineering fields and could be exploited for acoustical design. Evolutionary optimization is an iterative tool to increase the “fitness”—or optimality—of a predefined target value, in this case reflecting and non-reflecting geometries given any acoustical design brief. The iterative nature of an evolutionary solver—which evaluates each generation in terms of its proximity to the target value—enables acousticians/designers to continually assess results at different stages of the optimization process. The proposed algorithms optimize parameters such as size, shape, number or orientation of surfaces by defining raytracing target values (e.g., number of rays reaching a receiver after n-reflections, density of rays in a diffuse field). We implement this approach using standard software: the Galapagos solver within the Grasshopper framework, a parametric design tool in the Rhino 3D environment. The limitless design options offered by the parametric approach are thus made available for acoustical optimization. This method can be used on all scales of geometrical acoustics, from alignment of absorber panels to geometries of enclosed spaces, such as concert halls.
An acoustic near surface soil profiler using surface wave method
Authors: Lu Zhiqu
Published: May 2022

An acoustic soil profiler, using a so-called the high-frequency multi-channel analysis of surface waves (HF-MASW) method, has been developed, which uses surface (Rayleigh) waves to measure soil profile in terms of the shear (S) wave velocity as a function of depth, up to a 2.5 m deep below the surface. Several practical techniques have been developed to enhance the HF-MASW method, including (1) a variable sensor spacing configuration, (2) the self-adaptive method, and (3) the phase-only signal processing. Fundamentally, the S-wave velocity is related to soil mechanical and hydrological properties through the principle of effective stress. Therefore, the measured two-dimensional S-wave velocity images reflect the temporal and spatial variations of soils due to weather effects, geological anomalies, and anthropologic activities. Several HF-MASW applications will be reported, including (1) near surface soil profiling, (2) a long-term-survey for studying weather and seasonal effects, (3) short-term monitoring rain fall events, (4) detecting fraigpan layers, and (5) a farmland compaction study. This acoustic soil profiler can be used for agricultural, environmental, civil engineering, and military applications.
Acoustic oscillations of drag-reducing air pocket under fast boat with stepped bottom
Authors: Matveev Konstantin I.
Published: May 2022

One promising method for reducing water resistance of marine vessels is to create air pockets on their wetted hull surface. However, such pockets can experience acoustic oscillations when excited by periodic sea waves. These oscillations may reach high amplitudes at resonance conditions, when the air-pocket natural acoustic frequency approaches to the excitation frequency. This can lead to excessive air leakage from the pockets and eventual disintegration of air cavities, resulting in a loss of their drag-reduction effectiveness. A reduced-order acoustic model has been developed to analyze this process. Using realistic hull and air-pocket parameters, the model was applied to simulate acoustic oscillations of an air pocket under a fast boat. It is shown that increased damping inside air cavities can limit oscillation magnitudes to acceptable levels. Another strategy involves quick acceleration of the hull, so that time spent near the resonance condition is insufficient for substantial growth of high-amplitude acoustic oscillations. Active acoustic control can also be used to suppress the oscillations. [Work supported by the U.S. National Science Foundation under Grant No. 1800135.]
Cue selection in the perception of pitch in music and speech
Authors: Chan May Pik Yu , Kuang Jianjing
Published: May 2022

Spectral shape affects pitch perception; sounds with more high energy harmonics sound higher than sounds with low energy in higher harmonics. Flatter spectral slope corresponds to "tenser" voices while steeper spectral slope correlates to "breathier" voices in speech. In string instruments, the spectral slope differentiates sul ponticello and sul tasto. Listeners were found to integrate spectral slope cues in pitch perception in speech; however, work on music focused on cross-instrument differences, glossing over cue integration within instruments with fixed-formant frequencies. Furthermore, spectral cues and F0 co-vary in human pitch production, but are largely independent in instrumental music. It remains unclear whether music processing is as integrative as speech processing. In this study, listeners were given either speech or violin stimuli with identical pitch contour pairs, and were asked to decide whether the second contour was higher or lower in pitch compared to the first. The spectral slope of each sound was manipulated to include all combinations of “breathier”/“sul tasto” and “tenser”/“sul ponticello” sounding pairs. Results show that listeners integrate spectral slope cues in pitch perception in speech and violin stimuli similarly, with similar categoricity and shift. Overall, listeners with higher musicality have more categorical responses but no differences in shift.