Auditory Brainstem Responses to Continuous Speech

Friday, November 14, 2025, 4:00 p.m. Central Time

Professor Spencer B. Smith
Department of Speech, Language, and Hearing Sciences
Moody College of Communication
The University of Texas at Austin
https://slhs.utexas.edu/research/texas-auditory-neuroscience-lab

The Auditory Brainstem Response (ABR) is a non-invasive electrophysiological tool used to objectively assess hearing sensitivity and test neural integrity of the subcortical auditory pathway.  Traditionally, the ABR has been elicited using brief, transient stimuli like clicks or tone-bursts to provide broadband and frequency-specific threshold information.  However, these stimuli are limited by the trade-off between duration and frequency specificity:  shorter stimuli evoke more neural synchrony (i.e., stronger ABRs) but are less frequency specific, whereas longer stimuli are more frequency specific but evoke less neural synchrony (i.e., weaker ABRs).  The first part of this talk will discuss ABR stimulus optimizations that result in both larger and more frequency specific ABRs.  Such stimuli are gaining traction in clinics due to their ability to expedite ABR testing and improve response detection accuracy.  The second part of this talk will discuss how the same stimulus optimization principles can be applied to evoke ABRs to more complex stimuli, such as continuous speech samples.  The ability to measure ABRs to continuous speech may yield insights into neural processing of ecologically valid sounds.

Acoustic Wave Scattering in 1D and 2D Time Materials: Theory, Applications, and Realization

Friday, November 7, 2025, 4:00 p.m. Central Time

Dr. Dirk-Jan van Manen
Department of Earth and Planetary Sciences
Institute of Geophysics
ETH Zurich
Zurich, Switzerland
https://geophysics.ethz.ch/

Time materials are materials whose acoustic and/or electromagnetic properties change while waves propagate through them.  Waves can scatter forward and backward in space from such temporal inhomogeneities, but due to causality they cannot reflect back in time.  Backscattering at time boundaries has been exploited to construct volumetric time reversal mirrors that enable refocusing arbitrarily complex fields onto their original source location(s) by instantaneously reversing the propagation direction everywhere in space.  Time boundaries have also been used for frequency conversion, exploiting the fact that the wavenumber vector is fixed across a time boundary (and thus the frequency must change).  Finally, it is known that waves in media with space-time modulated properties exhibit reciprocity-breaking behavior.  I will present the theory of scattering in 1D and 2D acoustic time materials, with a focus on reciprocity relations.  I will show numerical examples of wave propagation in such materials, as well as of Green’s function retrieval.  I will also explore space-time materials that compute their own inverse.  Finally, I will discuss ongoing research efforts into the realization of time materials.

Acoustical Applications of Deep Learning: Wave Classification and Metamaterial Surrogate Models

Friday, October 31, 2025, 4:00 p.m. Central Time

Dr. William A. Willis
Applied Research Laboratories
The University of Texas at Austin
https://www.arlut.utexas.edu/

The use of machine learning (ML) has transformed the modern approach to scientific problem solving, and therefore recent work has sought applications in the field of acoustics.  With the large variety of both ML implementations and acoustics problems, it is important to apply ML techniques to well-suited problems while still exploring the limits of their utility.  This seminar will provide examples of recent acoustical applications of deep learning (DL), in which artificial neural networks with many layers are used to process complex datasets.  The seminar will focus on two applications from the works of the author.  The first is the application of convolutional neural networks to the classification of schlieren images of acoustic waves produced by a Mach 3 jet flow to identify waves undergoing coalescence, a phenomenon linked to increased nonlinear distortion.  The second application is the training of deep neural networks to capture force-displacement constitutive behavior of nonlinear elastic metamaterials for use in surrogate models that include complex deformation behaviors, such as plasticity, contact, and buckling.  The two applications represent very different subfields of acoustics but require the same knowledge of ML and DL fundamentals.

A Year in the Life of Acoustics Entrepreneurs

Friday, October 24, 2025, 4:00 p.m. Central Time

Jeff G. Schmitt, P.E.
VIacoustics
Austin, Texas
https://viacoustics.com/

VIacoustics is an Austin-based small business that specializes in systems and software for acoustic measurements and signal processing for a wide variety of applications.  Our four-person team moves from one application to another, in locations all over the world, with a new client every couple of weeks.  This presentation will take you on a whirlwind trip through the applications our team of acoustics entrepreneurs have worked on over the past year.  If you aspire to going into acoustic consulting, or starting a business based on something related to acoustics, this presentation is for you.  Or if you’re interested in the wide variety of practical applications in acoustics that a small team of acousticians and programmers takes on, you will find this presentation interesting and entertaining.  My colleagues and I will take you through a year of projects as diverse as measurement systems for hearing protection and communication systems for both industrial noise and military applications, noise emissions from HVAC equipment, CPAP devices and automated baby products, medical device alarms, firing range noise exposure for the FBI, impulsive noise dosimetry for soldiers and signal processing for psychoacoustic analysis, and swept sine measurements of acoustic properties of building materials.

Theory and Biomedical Applications of Quadratic Nonlinearity in Shear Wave Beams in Soft Tissue

Friday, October 17, 2025, 4:00 p.m. Central Time

Philip G. Kaufinger
Applied Research Laboratories and
Walker Department of Mechanical Engineering
The University of Texas at Austin

For both nonlinear plane compressional waves and nonlinear compressional wave beams, quadratic nonlinearity generates a second harmonic at leading order.  Conversely, plane nonlinear shear waves in isotropic media are subject only to cubic nonlinearity at leading order and therefore generate only odd harmonics during propagation.  Also, shear wave beams cannot generate a second harmonic at leading order even with curvature in the wavefronts unless the polarization of the beam is spatially varying.  Beginning with a nonlinear paraxial wave equation for shear wave beams in isotropic elastic media, closed-form analytical solutions are obtained for the fields at the source frequency and the second harmonic.  The analytical solutions are derived by perturbation for both the transverse and longitudinal particle displacement components in shear wave beams radiated by a source defined by spatially varying affine polarization, Gaussian amplitude shading, and quadratic phase shading to account for focusing.  The current discussion of shear wave beams is presented in the context of applications to transient elastography to measure tissue stiffness in the liver for the assessment of liver disease.  It is postulated that the second harmonic may be used to estimate the third-order elastic material property as an additional biomarker for diseased tissue.

Acoustic Imaging of Ocean Dynamics from Marine Seismic Surveys

Friday, October 10, 2025, 4:00 p.m. Central Time

Professor Likun Zhang
National Center for Physical Acoustics and
Department of Physics and Astronomy
University of Mississippi
https://olemiss.edu/profiles/zhang.php

Marine seismic surveys, widely used in oil and gas exploration, employ airgun sources and hydrophone arrays to image structures beneath the seafloor.  Beyond this primary purpose, the same surveys also capture faint reflections from ocean water columns, generated by acoustic impedance contrasts.  Processing these weak signals enables high-resolution imaging of oceanic structures such as eddies and internal waves—a field known as seismic oceanography.  With three-dimensional surveys using multiple parallel arrays, such reflections can even be used to track the movement of water columns over time.  This talk presents acoustic imaging of temporal and spatial variations in the Gulf of Mexico, showing how multichannel seismic data can be repurposed to study ocean dynamics.  By analyzing signal characteristics and applying tailored processing methods, we demonstrate how seismic observations can advance the imaging of fine-scale structure and the evolution of the ocean interior.

Acoustic Radiation Force: History, Theory, and Recent Advances

Friday, October 3, 2025, 4:00 p.m. Central Time

Chirag A. Gokani
Applied Research Laboratories and
Walker Department of Mechanical Engineering
The University of Texas at Austin

Musical Acoustics for Building Signal Processing Intuition and Understanding Instruments as Acoustic Filters

Friday, September 26, 2025, 4:00 p.m. Central Time

Dr. James M. Gelb
Applied Research Laboratories
The University of Texas at Austin
https://www.arlut.utexas.edu/

In Spring 2015 I introduced an undergraduate course in musical acoustics in the Walker Department of Mechanical Engineering designed for non-technical students. This course has been taught 8 times since then, evolving from a mix of non-technical and technical students to predominantly non-technical students to predominantly technical students (primarily Mechanical Engineering majors). In this seminar I will begin by covering general concepts in musical acoustics, and then provide insights into teaching technical material to students with a wide range of backgrounds. The course focuses on traditional acoustics with the theme of teaching the science of sound, treating instruments as filters, and providing an intuition for the physical and mathematical aspects of harmonics. The talk explains the physical generation of approximate pure and complex tones produced by actual instruments. In the process, you will also learn musical concepts of consonance and dissonance, and the structure and perception of musical scales.

Acoustics and Vibrations in Spatiotemporally-modulated Media

Friday, September 19, 2025, 4:00 p.m. Central Time

Dr. Benjamin M. Goldsberry
Applied Research Laboratories
The University of Texas at Austin
https://www.arlut.utexas.edu/

Over the past decade, there has been significant interest in studying acoustic and elastic wave behavior in materials with space- and time-dependent material properties. Spatiotemporal modulation of a medium’s properties both in space and time provides a means to control the wavenumber and frequency of propagating and scattered waves that otherwise does not exist in normal passive materials, and leads to novel wave behavior such as nonreciprocity. In finite domains with prescribed boundary conditions, spatiotemporal modulation can induce unique coupled mode effects, such as split resonances that are tunable with the modulation parameters. In this talk I will introduce wave propagation in spatiotemporally-modulated media, beginning with a brief summary of wave propagation in spatially periodic and temporally periodic media. This is followed by a derivation of a coupled mode approach for finite media with spatiotemporal modulation of the material properties. Lastly, our recent work on coupling evanescent and propagating modes in a waveguide with spatiotemporally-modulated impedance boundary conditions is presented, as well as a brief discussion of future research efforts on this topic.

Audio Forensics:  Recorded Audio Analysis with Case Examples

Friday, September 12, 2025, 4:00 p.m. Central Time

Steven D. Beck
Beck Audio Forensics
Austin, Texas
https://beckaudioforensics.com

Audio forensics is the field of forensic science relating to the acquisition, analysis, and evaluation of sound recordings that may be used as evidence in a court of law.  An Audio Forensics Expert must be able to answer specific questions related to the audio sources and acoustics involved in a crime scene, and to justify those answers with a reasonable degree of scientific certainty.  Some of the basic steps in an investigation involving audio analysis will be described.  A short history of some of the main application areas (authentication, voice, and gunshot analysis) will be presented, along with a discussion of applicable acoustics and signal processing techniques.  Finally, a number of “famous” audio forensics cases from the speaker’s recent work on unsynchronized receivers, community-based gunshot monitoring, and ballistic flow sounds will be presented.

Applied Research Laboratories:  Research in Support of National Security 

Friday, September 5, 2025, 4:00 p.m. Central Time

Dr. Karl B. Fisher
Executive Director
Applied Research Laboratories
The University of Texas at Austin
https://www.arlut.utexas.edu/

Applied Research Laboratories, The University of Texas at Austin (ARL:UT) is a Department of Defense University Affiliated Research Center (UARC).  In parallel with its UARC mission, ARL:UT advances the mission of our parent university of education, research, and public service.  Through fundamental research, innovative science, and applied engineering, ARL:UT makes significant contributions in support of national security.  We are proud that many of our contributions have a direct and positive impact for those who protect us through their military service.

Universities have long played a critical role in our nation’s defense.  A brief history of ARL:UT will be provided, followed by a general overview of the current research portfolio.  The talk will include examples of acoustics-related research covering basic research, prototyping, and the transition of capabilities in support of national security.

Development of Acoustic Remote Sensing of Seagrass Ecosystems and Understanding of their Climate Impacts

Friday, April 18, 2025, 4:00 p.m. Central Time

Dr. Megan S. Ballard
Applied Research Laboratories
The University of Texas at Austin
https://www.arlut.utexas.edu/

Seagrasses provide a multitude of ecosystem services and act as important carbon sinks. However, seagrass habitats are declining globally, and they are among the most threatened ecosystems on earth. For these reasons, long-term and continuous measurements of seagrass parameters are of primary importance for ecosystem health assessment and sustainable management. This talk will present results from both active and passive acoustical methods for ecosystem monitoring in seagrass meadows. Examples of both techniques will be presented based on data collected as part of a two-year continuous deployment of an acoustical measurement system operating in a seagrass bed dominated by Thalassia testudinum (turtle grass) in Corpus Christi Bay, Texas. From a propagation perspective using a broadband acoustic source, gas bodies contained within the seagrass tissue as well as photosynthetic-driven bubble production results in attenuation and scattering of sound that produces increased transmission loss. For the passive approach, the detachment of gas bubbles from the plants is an important component of the ambient soundscape. The data show annual trends related to the seasonal growth pattern of Thalassia as well as diurnal trends correlated with photosynthetically active radiation.

Piezoelectric Lithium Niobate for 6G, Sensing, and Power

Friday, April 11, 2025, 4:00 p.m. Central Time

Vakhtang Chulukhadze
Chandra Department of Electrical and Computer Engineering
The University of Texas at Austin
https://www.ece.utexas.edu/

Lithium Niobate (LN) has long been established as a key piezoelectric material, offering exceptional electro-mechanical coupling, low acoustic loss, and remarkable versatility owing to its strong piezoelectricity, pronounced anisotropy, and single-crystalline structure. Recently, advancements in thin-film transfer technology have made LN a prime solution for applications ranging from radio frequency (RF) devices to high-temperature dynamic pressure sensors, high SNR microphones, and compact power conversion. In the RF domain, LN has demonstrated outstanding performance at ultra-high frequencies, outperforming state-of-the-art alternatives and emerging as one of the leading candidates for enabling 6G mobile communication. Beyond RF, LN boasts incredibly high figures of merit for various transducer applications. Early investigations into LN-based microphones, piezoelectric micromachined ultrasound transducers (PMUT) and dynamic pressure sensors show promise due to the low loss tangent, high electro-mechanical coupling, and low residual stress in LN. At the same time, LN’s exceptionally high Curie temperature and absence of phase transformations below this threshold make it ideal for harsh-environment applications. These same properties make LN a compelling platform for piezoelectric power conversion, where acoustic resonators can leverage their inherent inductive characteristics to replace bulky magnetic inductors. In this seminar, we present our ongoing efforts to establish LN as a dominant piezoelectric platform for RF, transducer, and power conversion technologies. Our discussion will span novel device architectures, system-level integration challenges, and recent experimental advancements. We will also highlight key developments in wide-bandwidth acoustic transducers and innovative transducer designs enabled by LN’s uniquely rich electro-mechanical coupling tensor.

Influence of Additive Manufacturing Parameters on Acoustic and Dynamic Properties of Structures 

Friday, April 4, 2025, 4:00 p.m. Central Time

Dr. Christina J. Naify
Applied Research Laboratories
The University of Texas at Austin
https://www.arlut.utexas.edu/

Additive manufacturing (AM) or 3D printing has grown in popularity due to its accessibility and affordability for use in rapid prototyping and the fabrication of complex geometries not producible by other methods. Despite widespread use in the acoustics community, specifically in the area of acoustic metamaterials, many of the consolidated materials used in AM processes are under-characterized for relevant fabricated structures. This characterization problem is exaggerated by a wide range of choices that the user has to make when designing a printed part. These user selections can result in printing artifacts, either intentionally as in the case of structure infill, or unintentionally as in the case of deviations in printed geometry or density as a result of chosen settings or hardware. This talk will summarize recent efforts to characterize acoustic and vibration performance of structures built via fused deposition modeling, with the ultimate goal of enabling printed components with reliable performance over multiple length scales. Specifically, this talk will investigate 1) effects of print parameters used to reduce fabrication time, 2) machine-to-machine variability of bulk material and sub-wavelength resonator response, and 3) the use of infill settings to tune elastic wave speed.

Listening to Batteries: Ultrasonics as a Non-Invasive Tool to Classify the State of Health of Cylindrical Lithium-Ion Batteries 

Friday, March 28, 2025, 4:00 p.m. Central Time

Simón M. Bedoya
Walker Department of Mechanical Engineering
The University of Texas at Austin
https://www.me.utexas.edu/

Evaluating the degradation of lithium-ion batteries is essential for the safety and management of modern energy storage systems. Recent research has studied the use of ultrasonic testing for non-invasive assessment of state of health (SOH) in addition to conventional electrical monitoring methods. Determination of SOH is critical for the assessment of battery quality at the end of a battery’s “first” life, which occurs when a battery is retired at 70-80% SOH. Though retired batteries should not be used in high-power applications, they can still be valuable for second-life applications. Large volumes of end-of-life batteries will be entering the market in the coming years, and there is a need for efficient non-invasive techniques to categorize these end-of-life batteries according to their SOH. This research investigates the use of ultrasonic testing to characterize SOH in lithium-ion batteries. We employ a 64-element ultrasound array to obtain quantitative ultrasound frequency-based parameters – including mid-band fit, spectral slope, and intercept – from circumferential waves travelling around the cylindrical batteries. Thirteen cylindrical cells were tested to evaluate this method: three were pristine and ten were retired from the same source. The mid-band fit demonstrated that ultrasonic testing has the ability to discriminate between different SOH in accelerated degradation experiments of pristine batteries and for recovered second-life batteries with unknown historical usage. We then discuss the potential of this technique for future non-destructive battery health screening methods, providing important insights into the emerging market for second-life batteries.

Sensing in a Jerky World: Magnetostrictive-Based Vibration Sensors

Friday, March 14, 2025, 4:00 p.m. Central Time

Ehsan Vatankhah
Chandra Department of Electrical and Computer Engineering
The University of Texas at Austin
https://www.ece.utexas.edu/

Magnetostriction is the phenomenon where magnetization of a material results in a change in volume. In this presentation, we delve into the utilization of this transduction principle towards realization of vibration sensors. The magnetostrictive based vibration sensors stand in contrast to piezoelectric counterparts in that they exhibit an inherent response to jerk—the time derivative of acceleration—resulting in an accelerometer sensitivity that maintains a +6 dB/octave slope relative to frequency, up to the sensor’s first resonance and thus they excel in SNR performance at higher frequencies. In this presentation, we specifically look at two prototype sensors, a single-axis inertial sensor and a hydrophone constructed using giant magnetostrictive material Terfenol-D. We characterize the accelerometer’s sensitivity through two independent methods, yielding results that align with finite-element and reduced-order analytical analyses. This design features a low output impedance, akin to moving-coil geophones, thus eliminating the necessity for intermediary buffering electronics. For the hydrophone, sensitivity characterization is conducted in a highly reverberant tank. Due to the sensor’s susceptibility to electromagnetic interference (EMI), a specialized characterization methodology using the ring-down natural modes of the tank is employed. 

Advancing Breast Ultrasound Computed Tomography: Virtual Imaging Trials and AI 

Friday, March 7, 2025, 4:00 p.m. Central Time

Dr. Umberto Villa
Oden Institute for Computational Engineering and Sciences
The University of Texas at Austin
https://oden.utexas.edu

Ultrasound computed tomography (USCT) is a non-invasive, radiation-free, low-cost imaging modality that could help identify new biomarkers for early detection of breast cancer. Specifically, it can measure intrinsic tumor properties quantitatively by estimating biophysical parameters and produce high-resolution and high-contrast images of tissue acoustic properties, such as speed of sound, density, and acoustic attenuation. While breast USCT technologies (SoftVue, Delphinus Medical) have recently received FDA approval for use as an adjunct modality to digital mammography in the screening of asymptomatic women with dense breast tissue, computational and algorithmic challenges of USCT image reconstruction hinder widespread adoption in the clinic. Computer-simulation studies, also known as virtual imaging trials, provide researchers with an economical and convenient route to address these challenges, systematically exploring imaging system designs and image reconstruction methods. This talk presents a methodology for producing realistic three-dimensional (3D) numerical breast phantoms for enabling clinically relevant computer-simulation studies of USCT breast imaging. By extending and adapting an existing stochastic 3D breast phantom for use with USCT, methods for creating ensembles of numerical acoustic breast phantoms are established. These breast phantoms possess clinically relevant variations in breast size, composition, functional, optical, and acoustic properties, tumor locations, and tissue textures. A few case studies will be presented to demonstrate the use of the proposed phantoms to address the development and evaluation of model-based (3D full-waveform inversion) and learning-based (AI) methods to reduce image artifacts and improve vertical resolution for ring-array breast USCT systems. 

Measurement and Modeling of Three-Dimensional Acoustic Propagation From The New England Seamounts Acoustics Experiment 

Friday, February 28, 2025, 4:00 p.m. Central Time

Dr. Thomas S. Jerome
Applied Research Laboratories
The University of Texas at Austin
https://www.arlut.utexas.edu/

The New England Seamounts Acoustics (NESMA) experiment was a collaborative sea experiment sponsored by the Office of Naval Research that took place between 2022-2024 at the Atlantis II Seamount Complex in the North Atlantic Ocean with goals of characterizing oceanographic variability, biological diversity, and acoustic propagation in the dynamic environment surrounding the seamounts. Of particular interest is three-dimensional acoustic propagation, describing sound that is refracted or reflected outside the vertical plane connecting the source and receiver. During the 2023 field campaign, three single-hydrophone acoustic recorders were deployed for two months on the seafloor near the base of the Atlantis II Seamount to measure and characterize out-of-plane propagation effects. This talk provides an overview of this part of the experiment from deployment to analysis. Recordings of impulsive sound sources reveal the influence of the steeply sloped seamounts on bottom-interacting sound propagation. Time-delay analysis is used to estimate the direction of acoustic arrivals measured at the three recorders in order to identify out-of-plane propagation effects. Three-dimensional acoustic ray tracing is used to back-trace the detected arrivals by launching rays from the receiver array in the estimated arrival directions to investigate features on the seafloor and slope of the seamount responsible for producing the observed out-of-plane propagation effects. Then the full path from the source to the feature on the seafloor to the receivers is modeled using two- and three-dimensional forward ray tracing models for comparison with measured arrival times to refine reflection location estimates and assess the viability of ray tracing methods for modeling acoustic propagation in seamount environments. 

Impacts of Infauna and Organic Matter on Seabed Acoustics 

Friday, February 21, 2025, 4:00 p.m. Central Time

Dr. Kevin M. Lee
Applied Research Laboratories
The University of Texas at Austin
https://www.arlut.utexas.edu/

The seabed, although it composes nearly seventy percent of Earth’s geological surface, remains a frontier. Thus, better understanding of the benthic environment will be required for developing critical seabed infrastructure in support of national defense, the blue economy, and climate applications.   Because acoustic remote sensing is one of the most widely used methods for interrogating wide swaths of the seabed, better fundamental understanding of how benthic processes couple to seabed acoustic properties is also needed. In particular, the impacts of benthic biological processes and biogeochemical properties on surficial sediment acoustic properties and their variability are poorly understood. Nearly all ocean-bottom muddy sediments are consumed through the digestive processes of polychaete worms and other deposit-feeding invertebrates. These diverse infauna communities modify near-surface seabed structure through burrowing, tube-building, and bio-irrigation, contributing to spatiotemporal variability in sediment sound speed, attenuation, and other geoacoustic properties. Furthermore, the presence of microscopic intergranular organic matter impacts sediment cohesion and hence seabed stability, but we are only beginning to understand how this affects sediment acoustic properties or how those relationships can be exploited. This seminar will describe some recent and current basic research efforts in the ARL:UT Environmental Sciences Laboratory related to the intersection of seabed acoustics, biology, and biogeochemistry. 

Advancing Ultrasound Research: Innovations and Applications from an Industry Perspective 

Friday, February 14, 2025, 4:00 p.m. Central Time

Dr. Miguel Bernal
Verasonics Inc.
Kirkland, WA
https://verasonics.com

This talk explores the evolution of ultrasound technology from the origins of conventional line-scan imaging to the modern approaches of ultrafast ultrasound and pixel-based beamforming—the foundational innovation of Verasonics. Starting by outlining the key differences between traditional ultrasound and ultrafast imaging, it will become clear that having a platform that can acquire thousands of frames per second unlocks current and untapped potential in characterization and diagnosis within medical ultrasound imaging. Then, several advanced techniques that leverage ultrafast ultrasound are introduced. These include ultrasensitive Doppler, which enables the visualization of microvascular flow with unprecedented detail; functional ultrasound imaging, a powerful method for mapping brain activity; and ultrasound localization microscopy, which surpasses the diffraction limit to achieve super-resolution imaging of the microvascular. Working with our academic partners, the advancement of these techniques is being actively explored in addition to comparing Verasonics’ previous and next-generation platforms to assess performance improvements as well as previously unrealized capabilities. As these ultrafast techniques continue to advance, there is a growing need to extend them from 2D to 3D imaging, which presents challenges in maintaining high frame rates. To address this, Verasonics developed Sparse Random Aperture Compounding, a novel volume imaging technique designed to enhance frame rates for high-element-count transducer arrays while optimizing data acquisition efficiency. Through collaboration as well as internal research and development, Verasonics continues to push the boundaries of ultrasound, providing flexible and powerful tools to drive innovation across clinical and scientific domains.

Condition Monitoring of Dry Storage Canisters Using Helical Guided Ultrasonic Waves 

Friday, February 7, 2025, 4:00 p.m. Central Time

Guan-Wei Lee
Maseeh Department of Civil, Architectural and Environmental Engineering
The University of Texas at Austin
https://www.caee.utexas.edu

Dry Storage Canisters (DSCs) play a critical role in the safe storage of spent nuclear fuel rods. These canisters, constructed from welded stainless-steel plates, are susceptible to degradation mechanisms such as stress corrosion cracking, which could compromise their structural integrity over time. With the first DSCs in the United States deployed in 1986, there is a growing need to assess and monitor their condition to ensure long-term safety and reliability. However, these canisters are housed within concrete overpacks, significantly limiting access to their surfaces for inspection. Moreover, it is crucial to limit human exposure to radioactive environments during these inspections. To address these challenges, monitoring techniques compatible with robotic systems are essential, which require minimizing the number of sensing points for efficient robot operation. This work focuses on developing an efficient and reliable methodology for both active and passive monitoring of DSCs using helical guided ultrasonic waves (HGUW). This approach aims to overcome the constraints of limited accessibility while enabling accurate assessment of structural integrity.

Modeling Very Low Frequency Wind-Generated Ocean Noise

Friday, January 24, 2025, 4:00 p.m. Central Time

Dr. Christopher A. Stockinger
Applied Research Laboratories
The University of Texas at Austin
https://www.arlut.utexas.edu/

Historically, shipping is assumed to dominate ambient underwater acoustic Noise Levels (NL) from 10 to 100 Hz, however, the data acquired from the north hydrophone triplet of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) station at Crozet Island provides unique wind noise observations with minimal shipping interference. First, NL was correlated to local wind speed through a frequency dependent power relation, and second, the distant wind contributions were modeled through a source density and propagation model. For the source density model, wind-related noise was modeled as a layer of monopole sources located at a quarter-wavelength below the surface to replicate a dipole radiation pattern. The total acoustic intensity received by the array and the modeled wind-related source intensity were both related to wind speed through a power relationship where the two share the same frequency dependent exponent, n. The model parameters were computed empirically from the acoustic and wind speed data. The source layer model accurately predicts the NL within a standard deviation of 3 dB. An important observation is that the exponent n increases as frequency decreases and reaches a value around 7 at 10 Hz, which is much larger than often measured at higher frequencies.