bluuebunny/crossref_metadata_2025 huggingface dataset:
Manufacturing-aware design of multi-material asymmetric acoustic absorbers
Authors: Wiest Tyler J. , Seepersad Carolyn C. , Haberman Michael R.
Published: November 2021

Advances in additive manufacturing technology are promising for the creation of materials to control acoustic waves. This work presents the design of an acoustic metasurface (AMS) created from a periodic two-dimensional array of multi-material scatterers embedded in an elastomeric matrix. Finite element analysis (FEA) of the AMS shows that the absorption of acoustic energy is dependent on direction of incident wave propagation if the material properties are asymmetric within the scatterers while the acoustic transmission remains symmetric. Asymmetry of acoustic absorption is highly sensitive to small changes in scatterer geometry and property distribution. The AMS design must therefore consider inherent variability in manufacturing processes and the resultant stochastic asymmetric absorption performance of the as-built AMS, which is computationally expensive to determine using FEA. A machine learning classifier is trained to replace FEA and enable efficient robust design of the AMS via Monte Carlo simulations. The classifier is trained to be valid for a variety of characteristic manufacturing variations and the trivial expense to call it leads to significantly faster design with awareness of manufacturing variability. This work demonstrates how robust design approaches can be used to select fabrication methods suitable for acoustic materials. [Work supported by NSF and ONR.]
Introduction to the Department of Energy Leadership Computing Facilities
Authors: Muehleisen Ralph T.
Published: November 2021

Did you ever say to yourself "Boy I wished I had a bigger computer." Do you look at your computation and see that cloud computing is not a viable solution? Do you think your problem could benefit from *really* high performance computing but don't know where to start in trying to access and use it? Acoustics researchers typically fail to think "big" with respect to their simulations—finding ways to reduce and limit their problems to fit a single workstation, a small cluster, a small HPC, or the cloud. The Department of Energy (DOE) Leadership Computing Facilities (LCF) are a set of the highest performance publicly accessible computing facilities in the U.S. Summit at Oak Ridge National Laboratory and Perlmutter at Lawrence Berkeley National Laboratory are #2 and #5 of the Top500 HPC list. Two Exascale computers: Frontier at Oak Ridge and Aurora at Argonne National Laboratory are set to arrive in the next couple of years. This presentation will introduce the DOE LCF and several of the allocation programs by which researchers and industry can gain access and training to use these incredible facilities.
High-performance computing for long-range underwater acoustics
Authors: Kushida Noriyuki , Oliveira Tiago , Lin Ying-Tsong
Published: November 2021

The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) has been recording underwater signals using seven hydrophone stations which cover the entire oceans and provides the data publicly available. One of the lessons learned during the data analysis, such as in the ARA San Juan submarine tragedy, is that underwater sound propagation paths become complex in a long-range propagation, and as such, computer modelling, particularly three-dimensional (3D), can play an important role in understanding sound source location. The biggest stumbling block toward long-range 3D modeling is obviously its huge computational resource demand. In this presentation, we will discuss the GPU implementation of the 3D Split Step Fourier Parabolic Equation (SSFPE) solver, and the domain decomposition parallelization of our newly developed 2D + 1D Finite-Difference Time-Domain (FDTD) solver. The obtained computational performances are: (1) 3D SSFPE on GPU performs approximately 20 times faster than the original Matlab code and (2) the parallel speedup of the FDTD solver with domain decomposition up to 4 nodes is 98%. Although the performances on a larger system are still of interest, those results already enable us to tackle realistic problems. Results highlight the importance of using high performance computing for realistic global scale underwater acoustic simulations.
Reference-free AEC for Alexa Barge-In
Authors: Huang Yiteng , Zhang Tao
Published: November 2021

When an Alexa built-in device is in playback mode, users need to make extra effort to cut through acoustic echo from the audio playback (music or synthesized speech signals) to activate the wakeword detector and start talking to Alexa, i.e., to barge into the conversation. These are high-friction events where Alexa customers typically experience a higher false reject rate (FRR). The acoustic echo canceller (AEC) and beamformer in the multichannel Audio Front End (AFE) are essential to mitigate the effect. But when playback volume is high, AFE outputs still contain strong residual echoes which downstream wakeword detection models could have difficulty to handle. In this talk, we will present an innovative multi-microphones yet array-agnostic, reference-free AEC tailored specifically for wakeword detection. As opposed to the traditional AEC, the new approach has five practically attractive benefits: (1) reference-free and array agnostic (a blind method suitable for in-model implementations); (2) inherently immune to loudspeaker nonlinearities; (3) free of synchronization/alignment hassle; (4) more microphones, more gains; (5) kills two birds with one stone (cancels both echo and noise). A proof-of-concept experiment will be discussed to validate the effectiveness of the proposed novel algorithm.
Measurements and simulations of aerosol released while singing and playing wind instruments
Authors: Stockman Tehya , Zhu Shengwei , Kumar Abhishek , Wang Lingzhe , Patel Sameer , Weaver James , Spede Mark , Milton Donald , Toohey Darin , Vance Marina E. , Hertzberg Jean , Srebric Jelena , Miller Shelly
Published: November 2021

Outbreaks from choirs showed that singing brings potential risk of COVID-19 infection. There is less known about the risks of airborne infection from other musical performance, such as playing wind instruments or performing theatre. In addition, it is important to understand methods to reduce infection risk. In this study, we used a variety of methods, including flow visualization, aerosol and CO2 measurements, and computational fluid dynamics (CFD) modeling to understand the different components that can lead to transmission risk from musical performance and risk mitigation. This study was possible because of a partnership across academic departments and institutions and collaboration with the National Federation of State High School Associations and the College Band Directors National Association. Funding for this project was provided by an international coalition of music organizations. We found that plumes from musical performance were highly directional, unsteady, and vary considerably in time and space. Aerosol number concentration measured at the bell of the clarinet were comparable to singing. Face and bell masks attenuated plume velocities and lengths and decreased aerosol concentrations measured in front of the masks. CFD modeling showed differences between indoor and outdoor environments and that lowest risk of airborne COVID-19 infection occurred at less than 30 min of exposure indoors and less than 60 minutes outdoors.
Aerosol propagation and acoustic effects while singing with a face mask
Authors: Moore Thomas R.
Published: November 2021

The flow of aspirated breath while singing was studied using transmission electronic speckle pattern interferometry. The resulting images show that when a vocalist wears a facemask the aspirated aerosol generally does not propagate through the mask, but instead exits through the sides. The aerosol is then entrained in the upward flow created by the heat from the body of the vocalist. Studies of a professional soprano singing the same phrase while wearing several different masks revealed that all of the masks that were tested resulted in no detectable transmission of the aspirated aerosol through the mask. The acoustic spectra indicate that all of the masks reduce the relative power in frequencies above 1 kHz, but a singer’s mask has a higher transmission in this frequency range than the more commonly available masks.
Machine learning recognition of vibrational modes in ESPI data
Authors: Greene Maya , Hoffman Kurt R.
Published: November 2021

We present a neural network (NN), constructed in Mathematica, that classifies images generated by electronic speckle pattern interferometry (ESPI). The goal of this project was to use the program to identify features in the images representing resonance behavior of the object. Much of our data was collected from unfinished wood surfaces, resulting in only the appearance of nodal lines in our ESPI data rather than the concentric rings that are hallmarks of data from finished instruments. The NN described here was trained to give four different output classifications: no resonant features, concentric ring patterns, clear nodal line patterns, and weak resonance features that correspond to ambiguous features observed at the high and low edges of the resonance band. The NN was trained using a collection of images from scans by an interferometer of multiple wood plates, an aluminium plate, and guitar top plates. In order to improve the accuracy of the classifier, we also explored image filtering techniques to increase the contrast of the images. This NN will eventually automate the process of finding resonant frequencies in real time when scanning new surfaces.
Using convolutional neural networks to estimate pitch directly from steelpan audio signals
Authors: Malloy Colin , Ye Jason
Published: November 2021

Estimating the pitch, or fundamental frequency, of a monophonic audio signal is a fundamental task in computational audio analysis with many downstream applications such as automatic transcription. The current general state of the art method for pitch detection is CRéPE: a Convolutional Representation for Pitch Estimation. CRéPE is a deep convolutional neural network designed to estimate the fundamental frequency of an audio signal directly from the waveform. However, CRéPE, and other general pitch detection methods, do not perform well on steelpan audio. This is likely due to the steelpan's complex spectral characteristics that differentiate it timbrally from other sound sources. We combine a deep convolutional neural network architecture based on CRéPE with a training dataset of steelpan audio from several distinct sounding tenor steelpans to achieve improved tenor steelpan pitch detection directly from the audio signal. We assess our model's ability to generalize by evaluating it with a test dataset that includes audio samples from steelpans that have no samples as part of the training set and compare these results to CRéPE's performance on the same test dataset.
Description of jet noise sources in a generalized aeroacoustic framework
Authors: Prasad Chitrarth , Gaitonde Datta
Published: November 2021

The present investigation examines the use of a Generalized Aeroacoustic Framework (GAF) to provide insights into the mechanisms which convert turbulence energy into sound. A key step is the selection of Fluctuating Stagnation Enthalpy (FSE), from Momentum Potential Theory, as a generalized acoustic variable. The Navier–Stokes equations are rewritten as an exact, inhomogeneous, convected wave equation, which governs the generation and propagation of FSE from the jet shear layer to the far-field. Using benchmark LES databases as truth models, it is shown that the FSE, scaled by the ambient density, is a surrogate for pressure fluctuations away from the jet shear layer. Thus, sources terms in the FSE wave equation provide an improved understanding of the local mechanisms responsible for noise radiation from the jet shear layer. A systematic inspection of the instantaneous distributions of the FSE sources identifies the most acoustically relevant mechanisms in the jet shear layer. The linear component of the mechanism is responsible for the downstream noise signature due to the initial Kelvin–Helmholtz instability whereas the non-linear component is dominant further downstream and can be related to intermittent acoustic bursts near the core-collapse.
Examination of Mach wave coalescence in a Mach 3 jet flow
Authors: Willis William A. , Cormack John M. , Tinney Charles E. , Hamilton Mark F.
Published: November 2021

Prior acoustic measurements of the sound field produced by a laboratory-scale, Mach 3 jet flow [Baars et al., AIAA (2013); Fiévet et al., AIAA (2016)] showed a discrepancy between the theoretical prediction that shocks should not form, based on effective Gol’dberg numbers, and the apparent observation of steepened waves. This suggests an additional mechanism relating to wave coalescence is responsible for increased wave steepening. To better understand this new mechanism, high framerate schlieren images of sound waves propagating from the post potential core of the same Mach 3 jet are studied. A shock detection algorithm is developed to isolate shock-like features in the images and along the propagation path, which are then used to determine occurrences of coalescence-induced steepening in the flow. Numerical models of coalescing waves using the Khokhlov–Zabolotskaya–Kuznetzov (KZK) equation are then leveraged to determine identifiable characteristics of coalescence events to improve detection. POD-based reduced-order representations of the isolated events are then studied in a Lagrangian frame. Ensemble averages of tracked events are used to identify common patterns for coalescence, which is believed to contribute to “crackle” noise in full-scale jet flows. [WAW is supported by the ARL:UT Chester M. McKinney Graduate Fellowship in Acoustics.]
Acoustical measurements of a Delta IV Heavy launch (NROL-82)
Authors: Hart Grant W. , Mathews Logan T. , Anderson Mark C. , Durrant J. T. , Bassett Michael S. , Olausson Samuel A. , Houston Griffin , Gee Kent L.
Published: November 2021

On 26 April 2021, the BYU Acoustics Research Group made noise measurements during launch of a Delta IV Heavy rocket (NROL-82) from Vandenberg Space Force Base in California. Measurement locations ranged in distance from 330 m to 19 km from the launch pad. Some sensors were arranged in a rough arc of 1i–4 km radius and others were placed along both an east-west line and a north-south line. Because of nearby mountains, some measurement stations were able to be located above the vehicle at the pad. We were therefore able to measure the noise in the different directions and at different distances, spanning a large angular range. This presentation will discuss an overview of noise level, frequency, and temporal characteristics. Additionally, two stations consisted of 5-meter radius, multimicrophone vector probes. Using these probes we were able to track the trajectory of the rocket ascent; our acoustically traced trajectory agrees well with the actual trajectory data. The results of these analyses will be presented.
Overall sound pressure levels and peak directivity of the NROL-82 Delta IV Heavy Launch
Authors: Houston Griffin , Olausson Samuel A. , Mathews Logan T. , Anderson Mark C. , Durrant J. T. , Bassett Michael S. , Hart Grant W. , Gee Kent L.
Published: November 2021

Rocket launch noise has historically been analyzed for directivity and sound power. To compare against previous findings, this study uses data acquired from the NROL-82 Delta IV Heavy launch from Vandenberg Space Force Base, CA, USA. Rocket trajectory data are used to calculate the 3D angle between the plume and several measurement stations in the near and far fields. Overall sound pressure level, directivity, and sound power level are calculated, and the results compared across stations.
Predicting supersonic jet mode-switching using non-negative matrix factorization
Authors: Satish Aprameya , Karon Aharon , Medda Alessio
Published: November 2021

Imperfectly expanded supersonic jets contain a shock-cell structure in the jet plume which plays a role in generating screech tones along with other jet noise sources. Depending on the Mach number of the jet, two types of jet motion or “jet modes”—a toroidal mode and flapping mode may occur, resulting in the generation of different screech tones that are not harmonics of each other. At a given jet condition, these jet modes (and the corresponding screech tones) can switch between each other based on environmental conditions in a seemingly non-deterministic manner. Understanding when mode-switching occurs at a fine time resolution can provide better understanding of the sensitivity of the jet structure dynamics. This work presents the preliminary results of a novel method that predicts when a particular screech tone is active using non-negative matrix factorization. Using this technique, spectrograms of jet noise are decomposed into a set of basis vectors corresponding to the screech tones present in the jet, and a set of activation functions that indicate when each screech basis is dominant. An activation function comparison technique is then used to identify activations corresponding to mode-switching.
On the stability of parallel shear flows with embedded swirl
Authors: Zhao Lu , Farokhi Saeed , Taghavi Ray
Published: November 2021

The temporal stability of inviscid parallel shear flows with embedded swirl is investigated. The base flow is divided into three regions: an inner irrotational jet flow, a thin swirl layer on the outer rim of the nozzle, and an external potential flow outside the nozzle. The swirl distribution in the thin shear layer is of solid-body rotation and of Rankine type outside the nozzle. The axial velocity profile in the jet base flow is assumed to be top-hat. The linear dispersion relation was derived and solved numerically. A parametric study on the effect of swirl parameter, S, and the swirl layer thickness fraction, d, on the amplification rates of the unstable modes is performed. A helical instability wave with azimuthal wave number, m = –3, is the most unstable mode with S = 0.8 and  = 0.08. Our results indicate that the embedded thin layer swirl is capable of triggering the centrifugal instability waves to promote jet mixing. This powerful technique may be employed to mitigate jet noise without incurring significant thrust loss.
The International Data Centre infrasound processing system, a 25 years travel
Authors: Mialle Pierrick , Bittner Paulina , Applbaum David , Le Bras Ronan
Published: November 2021

In 2001, when the first data from an International Monitoring System infrasound station started to arrive in near real-time at the International Data Centre (IDC), its infrasound processing system was in a premature state. The IDC embarked for a multi-year design and development of its dedicated processing system, which led to operational IDC automatic processing and interactive analysis systems in 2010. In the next ten years the IDC produced over 40,000 infrasound events reviewed by expert analysts. In an effort to continue advancing its methods, improving its automatic system and providing software packages to Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) users, the IDC focused on several projects. First, the automatic system for the identification of valid signals was redesigned with the development of DTK-(G)PMCC (Progressive Multi-Channel Correlation), which is made available to CTBTO users within NDC-in-a-Box. And second, an infrasound model was developed for automatic waveform network processing software NET-VISA with an emphasis on the optimization of the network detection threshold by identifying ways to refine signal characterization methodology and association criteria. Ongoing and future improvements of the IDC processing system are planned to further reduce analyst workload that includes atmospheric propagation modeling and enhancements of the automatic pipeline components.
Source estimation through sensitivity-based mode decomposition of sequential data
Authors: Millet Christophe
Published: November 2021

Characterizing explosions from infrasound is usually performed using posterior probability density functions (PDFs), which involves a large number of propagation model runs. These propagation models require atmospheric specifications and a model for representing small-scale atmospheric fluctuations, such as gravity waves. While defining a proper probabilistic model for the input parameters of these models may become a burden, in real-world cases, only a limited number of input parameters happens to influence the acoustic waveforms significantly. These parameters can be selected using quantitative importance measures or sensitivity indices that allow one to rank the sources of uncertainty. In this work, we introduce a method which is able to extract information from these sensitivity indices in time-frequency space, using waveforms generated by a full-wave propagation model. The extracted modes can be used to determine the relevant patterns that contribute most to the sensitivity captured in the data sequence or to project the perturbed model onto a system of fewer degrees of freedom. The restriction of the likelihood to subdomains where the sensitivity to gravity waves is weak allows a better estimate of the posterior PDF for source parameters. Demonstrations of the method are presented using waveforms recorded at thousands of kilometers of explosions.
Progress toward an acoustic point to point ray tracing method in a stratified atmosphere with wind
Authors: Heath Stephanie L. , Cobb Ethan
Published: November 2021

NASA is investigating acoustic propagation capabilities to accommodate a point to point propagation prediction scheme defining a ray between a specific source–observer pair in an inhomogeneous stratified atmosphere with wind. A 4D space-time ray method based on the null geodesic equations yields two main benefits over classical 3D Euclidian reduced ray equations: (1) it poses a valid two point boundary value problem for the rays connecting two locations; and (2) the solution method is valid throughout the whole domain including at ray turning points without the need for piecewise definitions. The resulting two point boundary value problem and the constant horizontal slowness vectors, which are a result of the stratified medium assumption, allow the desired (t, x, y, z) ray trace. The presentation highlights the equations and inputs required to solve the 4D ray trace. The solution to this two point boundary value problem will create the groundwork for efficient future NASA propagation codes.
Three-dimensional parabolic equation for infrasound propagation above topography
Authors: Khodr Codor , Azarpeyvand Mahdi , Green David
Published: November 2021

The parabolic equation (PE) is one of the most popular methods for the modeling of low-frequency sound in the atmosphere. Over the past decades, considerable efforts have been dedicated to the inclusion of medium inhomogeneities, such as wind and turbulence, extending the PE to more realistic atmospheric conditions. On the other hand, few models take topography into account, while its effects on infrasound propagation are important in some cases. A new development has enabled the inclusion of irregular terrain in the narrow-angle 3DPE for a moving inhomogeneous medium [Khodr et al., JASA (2020)]. A coordinate transform similar to the Beilis-Tappert mapping used in 2D [Parakkal et al., JASA (2012)] is introduced to account for the variation in topography. The numerical solution relies on a Crank–Nicolson implicit scheme along the propagating direction. The pressure field at every step is computed with an iterative fixed-point algorithm which consists of a succession of tridiagonal systems that can be efficiently solved. A validation is performed against 3D Boundary Element simulations for propagation above a Gaussian hill in a homogeneous atmosphere. The existence of transversal scattering in the shadow zone, not represented by 2D models, is highlighted. Further developments include the extension of the method to a split-step wide-angle formulation. [This work was conducted at the University of Bristol in partnership with AWE Blacknest.]
Simulations of local and regional scale infrasound propagation in the Arctic
Authors: Wilson D. Keith , Shaw Michael J. , Ostashev Vladimir , Muhlestein Michael B. , Swearingen Michelle E. , McComas Sarah
Published: November 2021

High-resolution, three-dimensional reconstructions of the Arctic atmosphere (the Arctic System Reanalysis version 2) are employed as input to wide-angle parabolic equation calculations to simulate infrasound propagation through Arctic weather conditions. The calculations involve horizontal distances out to 200 km (i.e., local and short regional scales), for which interactions with the troposphere and lower stratosphere dominate. The atmospheric phenomena examined include sudden stratospheric warmings (SSWs), strong polar lows, and boundary-layer phenomena such as low-level jets (LLJs), katabatic winds, and surface-based temperature inversions. The SSWs and polar lows are found to be opposites from an acoustic refraction standpoint: the former weaken upward refraction by temperature gradients in the troposphere, thus creating strongly asymmetric wind-dominated refraction, whereas the latter enhance negative temperature gradients in the troposphere, thus leading to prevailing upward refraction conditions. The LLJs and surface-based inversions are found to create particularly strong surface ducting conditions. Horizontal variations in the atmospheric profiles, in response to changes in topography and surface property transitions such as ice boundaries, significantly impact the propagation.
Deep learning-based age estimation using B-mode ultrasound tongue imaging
Authors: Xu Kele , Csapó Tamás G. , Feng Ming
Published: November 2021

The feasibility of age estimation is explored using the ultrasound tongue image of the speakers. Motivated by the success of deep learning, a deep convolutional neural network model is trained on the UltraSuite dataset. The deep model achieves mean absolute error (MAE) of 2.03 years for the data from typically developing children, while MAE is 4.87 for the data from the children with speech sound disorders, which suggest that age estimation using ultrasound is more challenging for the children with speech sound disorder. Also, we explore to visualize what does the deep model learn for the age estimation task. We firstly visualize the convolutional layers in the learned convolutional neural networks. We observe that the deep model not only focuses on the contour in the ultrasound tongue image, but also pays more attention to the regions corresponding to the tendon and tongue root regions, which may provide guidance for future ultrasound tongue imaging interpretation tasks. The developed method can be used a tool to evaluate the performance of speech therapy sessions.
Acoustic spaces for normal and pathological voices
Authors: Lee Yoonjeong , Kreiman Jody
Published: November 2021

What does it mean for a voice to sound normal? Our recent work comparing listener judgements of talkers with and without a diagnosed voice disorder showed that judgments of “normal” versus “not normal” and strategies for estimating how much a given voice deviates from normal depended on the listener, the context, the purpose of the judgement, and other factors as well as on the voice. F0, F1 and F2, and F0 variability were significant predictors of both categorical judgments and of scalar normalness ratings, but between-listener inconsistency in the perceptual models was observed. The present study examined acoustic spaces for the same normal and pathological voices by performing principal component analysis on scaled values of F0, formant frequencies, spectral noise, source spectral shape, and their variability. Acoustic spaces for normal and disordered talkers had similar structures, and included measures related to source spectral shape, F1, and higher formant frequencies. Overall, variability in noise was only important for pathological voices. The ways in which acoustic voice spaces are related to listener perceptions of a voice are discussed. [Work supported by NIH/NSF.]
A cross-linguistic investigation of acoustic voice spaces
Authors: Lee Yoonjeong , Garellek Marc , Esposito Christina , Kreiman Jody
Published: November 2021

This study examines the extent to which the phonological structure of a language impacts acoustic variation in voice spaces for individuals and populations of speakers. Our recent work on two typologically different languages, American English and Seoul Korean, showed striking similarities in the acoustic spaces derived from Korean and English voices, but also notable differences in the importance of F0 and variability in vowel quality that were related to phrasal intonation patterns present in the Seoul dialect, but not in English. The present study examined eight speakers (5F) of Hmong, a language with tone and phonation contrasts. We performed principal component analysis on scaled values of F0, formants, spectral noise, source spectral shape, and their variability, measured from vowels, and compared results to Korean and English (which lack tone and phonation contrasts). Results revealed both substantial similarities and differences across languages. F0 commonly emerged only for Hmong and Korean voices, and H1-H2 (correlated with phonation) accounted for substantial variation only in Hmong voices. Our findings suggest that both biologically and phonologically relevant factors shape acoustic voice spaces, and point to a potential mechanism for the “own language” advantage in speaker perception. [Work supported by NIH/NSF.]
Managing vessel-generated underwater noise to reduce acoustic impacts to killer whales
Authors: Trounce Krista , MacGillivray Alexander , Wood Jason
Published: November 2021

Launched in 2014, the Enhancing Cetacean Habitat and Observation (ECHO) Program, led by the Vancouver Fraser Port Authority, is a regional, collaborative program designed to better understand and reduce the cumulative effects from commercial shipping activities on at-risk whales. The program advances a number of research projects and operational initiatives, with a key focus on reduction of vessel-generated underwater noise to support recovery of the endangered Southern Resident Killer Whale (SRKW). To reduce vessel noise in key killer whale habitat, the ECHO Program manages seasonal voluntary slowdowns of large commercial traffic and lateral displacement of inshore traffic, and advances projects to better characterize vessel-generated noise. Determining the efficacy of vessel noise reduction efforts requires careful consideration of confounding factors to assess acoustic reductions, and estimate the resulting benefits to SRKW. This presentation will highlight results of noise mitigation efforts conducted to date, and identify some of the technical challenges faced in the acoustic analysis, including decisions on data filtering techniques. Methods used by the ECHO Program for evaluating potential effects of noise exposure on killer whale behavior and foraging will also be discussed.
In situ monitoring of polymer 3D printing using ultrasonic Lamb waves generated by a 3D printed wedge
Authors: Kizer Nathan , Kube Christopher M.
Published: November 2021

The additive manufacturing (AM) of polymers has become increasingly popular in industry to create complex geometries for parts while maintaining low manufacturing costs. Rapid nonuniform cooling introduced during the printing process can lead to part warping and delamination which are precursors to part failure and/or poor part quality. Previous researchers have integrated online monitoring techniques such as optical or thermal sensors. These techniques are limited to monitoring exposed areas of the part leaving unexposed areas unmonitored. In this work, ultrasound has been implemented to monitor the inaccessible areas where defects can originate. An in situ guided wave-based ultrasonic inspection system was implemented into the test setup to detect delamination during printing. A 3D printed ultrasonic wedge was designed to generate S0 guided waves that were received by a broadband pinducer. The wedge was printed onto a plate of 6061 aluminum acted as the print bed for the experiments. A 3D printed part was printed between the transducers, which was continuously monitored for signs of delamination. This presentation will report on precursors to part delamination that are difficult or impossible to sense using previous methods. This work seeks to reduce 3D part failures and, thus, polymer waste associated with 3D printing.
Effect of pulse duration and repetition rate on burst wave lithotripsy stone fragmentation in vitro
Authors: Kim Ga Won , Hunter Christopher , Maxwell Adam , Cunitz Bryan W. , Bailey Michael R. , Kreider Wayne
Published: November 2021

Burst wave lithotripsy (BWL) is a noninvasive technology to fragment urinary stones using short pulses of focused ultrasound. The aim of this study was to assess how different combinations of pulse length and pulse repetition frequency (PRF) impact stone fragmentation rate and cavitation activity in an in vitro-model. Human calcium oxalate stones between 4–7mm were exposed in a tissue phantom with a 350-kHz BWL transducer with a beamwidth of 6 mm. Treatments were delivered in a 45–50% degassed water bath. Ultrasound imaging was used to target the stone and monitor cavitation activity around the stone. Stones were exposed to ten different parameter sets at peak negative pressure = 6.2 MPa in 5-min intervals up to 30 min total. After each interval, the remaining mass of fragments >2mm was measured to determine the rate of comminution. Longer pulse duration generally produced improved fragmentation. Increasing the pulse repetition rate with set pulse duration did not always produce faster comminution. The results suggest that more effective fragmentation may be achieved in BWL by long pulse durations and low PRF. [Work funded by NIDDK, Grants P01 DK043881 and K01 DK104854. Maxwell, Cunitz, and Bailey have consulting agreements with and equity in SonoMotion, Inc.]
Sonoluminescence as a probe of conditions during cavitation
Authors: Suslick Kenneth S.
Published: November 2021

Acoustic cavitation occurs in all liquids irradiated with sufficient intensity of sound or ultrasound. The collapse of such bubbles creates local heating and provides a unique source of energy for driving chemical reactions. In addition to sonochemical bond scission and formation, cavitation also induces light emission in many liquids. This phenomenon of sonoluminescence (SL) and has captured the imagination of many researchers since it was first observed 85 years ago. SL provides a direct probe of cavitation events and has provided most of our understanding of the conditions created inside collapsing bubbles. Spectroscopic analyses of SL from single acoustically levitated bubbles as well as from clouds of bubbles have revealed molecular, atomic, and ionic line and band emission riding atop an underlying continuum arising from radiative plasma processes. These studies permit quantitative measurement of the intracavity conditions: relative peak intensities for temperature measurements, peak shifts and broadening for pressures, and peak asymmetries for plasma electron densities. Extraordinary conditions are generated inside the collapsing bubbles in ordinary room-temperature liquids – observable temperatures exceeding 15 000 K, pressures >1000 bar, and heating and cooling rates in excess of 1012 K/s. For clouds of cavitating bubbles, multibubble sonoluminescence (MBSL) reveal slightly more moderate local conditions inside bubble clouds of ∼5000 K, ∼300 atm. Biomedical applications of SL will be discussed.
Recovering From the Houston Astros’ Sign-Stealing Scandal: A Case Study on Protecting a Professional Sport Organization’s Reputation Through Crisis Communication
Authors: Selvaratnam Vinu
Published: November 2021

In early 2020, the Commissioner of Major League Baseball, Rob Manfred, announced the Houston Astros sign-stealing scandal after months of investigation. It was one of the biggest scandals in baseball since the steroid era. After the fallout of this scandal, Major League Baseball’s reputation has suffered as stakeholders have increasingly lost faith in the organization’s ability to function ethically. This case study focuses on Manfred’s newly appointed Chief Communications Officer, Bhavna Krishnamurthy, who is tasked with repairing the organization’s reputation. The case presents a real-life incident as a backdrop to discuss crisis communication, particularly from a North American professional sport organization perspective.
Can We Modify Maximal Speed Running Posture? Implications for Performance and Hamstring Injury Management
Authors: Mendiguchia Jurdan , Castaño-Zambudio Adrián , Jiménez-Reyes Pedro , Morin Jean–Benoît , Edouard Pascal , Conceição Filipe , Tawiah-Dodoo Jonas , Colyer Steffi L.
Published: November 2021

Purpose: Sprint kinematics have been linked to hamstring injury and performance. This study aimed to examine if a specific 6-week multimodal intervention, combining lumbopelvic control and unning technique exercises, induced changes in pelvis and lower-limb kinematics at maximal speed and improved sprint performance. Methods: Healthy amateur athletes were assigned to a control or intervention group (IG). A sprint test with 3-dimensional kinematic measurements was performed before (PRE) and after (POST) 6 weeks of training. The IG program included 3 weekly sessions integrating coaching, strength and conditioning, and physical therapy approaches (eg, manual therapy, mobility, lumbopelvic control, strength and sprint “front-side mechanics”-oriented drills). Results: Analyses of variance showed no between-group differences at PRE. At POST, intragroup analyses showed PRE–POST differences for the pelvic (sagittal and frontal planes) and thigh kinematics and improved sprint performance (split times) for the IG only. Specifically, IG showed (1) a lower anterior pelvic tilt during the late swing phase, (2) greater pelvic obliquity on the free-leg side during the early swing phase, (3) higher vertical position of the front-leg knee, (4) an increase in thigh angular velocity and thigh retraction velocity, (5) lower between-knees distance at initial contact, and (6) a shorter ground contact duration. The intergroup analysis revealed disparate effects (possibly to very likely) in the most relevant variables investigated. Conclusion: The 6-week multimodal training program induced clear pelvic and lower-limb kinematic changes during maximal speed sprinting. These alterations may collectively be associated with reduced risk of muscle strain and were concomitant with significant sprint performance improvement.
Upper-Limb Force–Time Characteristics Determine Serve Velocity in Competition Tennis Players
Authors: Baiget Ernest , Colomar Joshua , Corbi Francisco
Published: November 2021

Purpose: (1) To analyze the associations between serve velocity (SV) and various single-joint upper-limb isometric force–time curve parameters, (2) to develop a prediction model based on the relationship between these variables, and (3) to determine whether these factors are capable of discriminating between tennis players with different SV performances. Method: A total of 17 high-performance tennis players performed 8 isometric tests of joints and movements included in the serve kinetic chain (wrist and elbow flexion [EF] and extension; shoulder flexion [SHF] and extension [SHE], internal [SHIR] and external rotation). Isometric force (IF), rate of force development (RFD), and impulse (IMP) at different time intervals (0–250 ms) were obtained for analysis. Results: Significant (P < .05 to P < .01) and moderate to very large correlations were found between SV and isometric force (IF), RFD and impulse (IMP) at different time intervals in all joint positions tested (except for the EF). Stepwise multiple regression analysis highlighted the importance of RFD in the SHIR from 0 to 50 milliseconds and isometric force (IF) in the SHF at 250 milliseconds on SV performance. Moreover, the discriminant analyses established SHIR RFD from 0 to 30 milliseconds as the most important factor discriminating players with different serve performances. Conclusions: Force–time parameters in upper-limb joints involved in the serve moderate to very largely influence SV. Findings suggest that the capability to develop force in short periods of time (<250 ms), especially in the shoulder joint, seems relevant to develop high SV in competition tennis players.
Association Between Knee Moments During Stair Navigation and Participant-Related Factors in Individuals With Anterior Cruciate Ligament Reconstruction: A Cross-Sectional Study
Authors: Kaur Mandeep , Ribeiro Daniel Cury , Webster Kate E. , Sole Gisela
Published: November 2021

Context: Altered knee joint mechanics may be related to quadriceps muscle strength, time since surgery, and sex following anterior cruciate ligament reconstruction (ACLR). The aim of this study was to investigate the association between knee moments, with participant-related factors during stair navigation post-ACLR. Design: Cross-sectional study. Methods: A total of 30 participants (14 women) with ACLR, on average 7.0 (SD 4.4) years postsurgery were tested during stair ascent and descent in a gait laboratory. Motion capture was conducted using a floor-embedded force plate and 11 infrared cameras. Quadriceps concentric and eccentric muscle strength was measured with an isokinetic dynamometer at 60°/s, and peak torques recorded. Multiple regression analyses were performed between external knee flexion and adduction moments, respectively, and quadriceps peak torque, sex, and time since ACLR. Results: Higher concentric quadriceps strength and female sex accounted for 55.7% of the total variance for peak knee flexion moment during stair ascent (P < .001). None of the independent variables accounted for variance in knee adduction moment (P = .698). No significant associations were found for knee flexion and adduction moments during for stair descent. Conclusion: Higher quadriceps concentric strength and sex explains major variance in knee flexion moments during stair ascent. The strong association between muscle strength and external knee flexion moments during stair ascent indicate rehabilitation tailored for quadriceps may optimize knee mechanics, particularly for women.
Strength through high slip-plane density
Authors: Yeh Jien-Wei
Published: November 2021

Subjecting a multicomponent alloy to cyclic torsion can create a strong, ductile material
The head and the heart of fear
Authors: Christianson John P.
Published: November 2021

The insular cortex calibrates brain, body, and behavioral responses to danger
Distribution of Microbial Community Structure in Sediment from the Suyeong River and Bay of Busan, Republic of Korea, Determined by 16S rRNA Gene Amplicon Sequencing
Authors: Jeong Ilwon , Lee Junho , Kim Jong-Oh , Yoon Seokjin , Kim Kyunghoi
Published: November 2021

Here, we report a 16S rRNA gene amplicon sequence analysis presenting the microbial community in sediments from the Suyeong River and Suyeong Bay, Republic of Korea. The dominant phyla in all sediment samples were
Proteobacteria
(39.69 to 53.62%) and
Bacteroidetes
(29.78 to 33.89%).
An “Uncharacterized” Australian Virus Is the Earliest Known Example of Ross River Virus with Changes in the nsP3 Protein Associated with the Explosive Outbreak of Ross River Virus Infection in the Pacific Region from 1979 to 1980
Authors: Aaskov John G. , Graham Melissa , Liu Wenjun
Published: November 2021

Ross River virus recovered from a South Australian patient during an outbreak of epidemic polyarthritis in 1971 is the earliest known genome sequence with the duplicated 12-amino-acid motif in the nsP3 protein that was found in strains responsible for the outbreak of epidemic polyarthritis in the Pacific region in 1979 to 1980.
Complete Genome Sequence of
Halomonas
sp. Strain FeN2, a Novel Cathode-Oxidizing Bacterium Isolated from Catalina Harbor Sediments
Authors: Vu Linda , Sackett Joshua D. , Leach Edmund , Wilbanks Elizabeth , Rowe Annette R.
Published: November 2021

We report the complete, closed, circular genome of
Halomonas
sp. strain FeN2, a metabolically versatile electrotroph that was isolated from Catalina Harbor sediments. The 4.8-Mb genome contains 4,286 protein-coding genes and has complete glycolytic, tricarboxylic acid, glyoxylate, pentose phosphate, and reductive pentose phosphate pathways. FeN2 also contains genes for aerobic and anaerobic (denitrification) respiration.
Complete Genome Sequences of Mycobacterium farcinogenes Strains Isolated from Clinical Specimens from Patients in Thailand
Authors: Sodsai Pimpayao , Jenjaroenpun Piroon , Hirankarn Nattiya , Wongsurawat Thidathip , Rotcheewaphan Suwatchareeporn
Published: November 2021

Mycobacterium farcinogenes
is a nonchromogenic, slowly growing
mycobacterium
that is responsible for bovine farcy. Here, we report two complete genome sequences of
Mycobacterium farcinogenes
strains isolated from skin and liver abscesses from patients in Thailand.
Immune-mediated ophthalmoparesis with anti-GD1a antibodies
Authors: McKean Norma , Chircop Charmaine
Published: November 2021

A young woman presented to neurology with a 1 month history of progressive diplopia on lateral gaze and a 1 week history of headaches. On examination she was found to have complex ophthalmoparesis with binocular horizontal diplopia, failure of abduction bilaterally and limited upgaze with convergence-retraction nystagmus. The rest of the neurological examination was normal. She was admitted for investigations: blood, CT brain, MR brain and lumbar puncture results were normal. Anti-GD1a antibodies were strongly positive; anti-GM1, anti-GM2 and anti-GD1b were also positive. On follow-up 3 weeks later, the complex ophthalmoplegia persisted. It was decided to treat with intravenous immunoglobulins (IVIgs) with good response but recurrence at 2 weeks post infusion. She was treated with 4 weekly IVIg courses and remains responsive and controlled over 1 year since presentation but becomes symptomatic in the week running up to each dose; thus, disease modifying treatment is currently being considered.