bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency-difference beamforming and sparse processing
Authors: Park Yongsung , Gerstoft Peter
Published: July 2024

Frequency-difference processing enables the estimation of the direction of arrival (DOA) for sources beyond the spatial aliasing frequency. The beamforming method takes advantage of the frequency difference between multiple frequencies, enabling processing at a lower frequency than the aliasing frequency. During this process, the number of DOAs we need to estimate becomes squared, and we require a high-resolution DOA estimator. Sparse processing has demonstrated high-resolution capabilities in DOA estimation, resulting in beamforming spectra with sharp peaks and enhancing resolution for accuracy. This presentation proposes the utilization of both frequency-difference processing and sparse processing. The suggested method is an aliasing-free beamformer for high-frequency sources using frequency-difference processing and achieves high-resolution capability using sparse processing.
Test method for diaphragmatic bass traps in a revberation chamber
Authors: Lenz Richard L.
Published: July 2024

For decades the limitations of ASTM C423 and ISO 354 have been confined to frequencies above 100Hz. While many attempts have been made to provide low frequency test data using these standards, they all go beyond the actual standards. A significant problem with testing low frequencies in reverberation chambers has to do with using the diffuse field, or standard test area, of the lab. Low frequencies do not propagate in these areas to the level of the standard test range. Additionally, the devices, specifically diaphragmatic low frequency absorbers, are not used in the diffuse field of rooms. They are generally designed to be placed in, or near, corners of rooms, or modal areas, where low frequencies do propagate. This test method will show experiments and the process of determining how to test diaphragmatic low frequency devices using the modal zone of the chamber. These tests are intended to be presented to ASTM in order to develop an addendum to C423 for testing low frequencies and the lab limitations based on size and other factors.
A real-world Lexicon 960L reverberation chamber: Simulating a hardware reverberation unit in virtual acoustics
Authors: Aydin Aybar , Baran Vlad , Zhang Kathleen Ying-Ying , Kelly Jack , King Richard , Woszczyk Wieslaw
Published: July 2024

The second generation of the Virtual Acoustic Technology (VAT) Laboratory at McGill University features a new real-time auralizer with a feedback canceller developed by CCRMA at Stanford University, allowing for the simulation of virtual acoustic environments with exceptionally high gain. This study is part of an ongoing research effort focused on integrating algorithmic reverberation tools designed for audio post-production into virtual acoustics at McGill University’s VATLab. Previous work has been done using impulse responses (IRs) captured from various acoustic spaces. In contrast, this study focuses on using IRs captured from the legendary Lexicon 960L hardware reverberation unit and using them in the VATLab for recording sessions with musicians. Various 5.1 multichannel presets have been captured as IRs and 3 groups of related 5 channel IRs have been loaded into the existing 15 speaker system of VATLab to simulate a real world, physical Lexicon 960L “environment” through virtual acoustics. Objective measurements following the ISO 3382-1 and 3382-2 standards in the VATLab have been performed to measure the effect of the physical room and analyze the effects of changing different algorithmic reverb parameters such as Diffusion, Early Level Master Control, Early Rolloff, Early or Reflection Delays on the simulated acoustical environments.
Virtual acoustics in distributed performance over a closed audio network
Authors: Zhang Kathleen Ying-Ying , Baran Vlad , Aydin Aybar , Oikonomidis Michail , King Richard , Woszczyk Wieslaw
Published: July 2024

We explore an application of active acoustics used to produce a shared virtual environment for live musical performance. As part of a concert given in the Immersive Media Lab at McGill University, musicians and audience members were located in adjacent but acoustically isolated spaces on the same digital audio network. With computer generated effects and live instruments, the concert consisted of electroacoustic performances that utilized dynamic virtual environments produced by our Virtual Acoustic Technology (VAT) system as an improvisatory partner and a mixing device to blend the diffusion of electronic and acoustic musical sources. The performance, including its evolving virtual environment, was captured using spatial microphone techniques and distributed in real-time to the audience over an immersive loudspeaker system in an adjacent control room. Audience members were given the opportunity to visit the musicians’ performance space in order to compare the reproduction to the original environment. Overall, the blending of computer-generated and acoustic sources created a specific use case for virtual acoustics, while the immersive capture and distribution method examined an avenue for producing a real-time shared experience. Future work in this area includes audio networks with multiple virtual acoustic environments and distributions.
Soundscape characterization in the Central Arctic Ocean ecosystem (Svalbard) using acoustic indices
Authors: Lynn Andrea
Published: July 2024

An increasingly warmer, less frozen Arctic is opening further to vessel traffic, transforming dominant ambient noise sources in the underwater soundscape. Chief sources may be shifting from wind to ship noise. Collecting data that help explain the changing composition of the soundscape may offer insights to guide regulation of noise in the ocean, furthering management and conservation efforts. Hydrophones connected to field recorders were used in this study to characterize the soundscape and to study marine mammal presence and ship noise. Hydrophones were deployed at 44 locations from a 13.8 m Ovni 445 sailing vessel between 9° E and 19° E and 69° N and 80° N in April 2023. Acoustic indices were utilized to assess soundscape composition. Vessel locations were confirmed using Automatic Identification System (AIS) marine traffic data. Wind, waves, and ice (geophony) dominated the soundscape’s acoustic signature in remote locations, while human-caused sounds (anthrophony) were significant near Arctic shipping routes, fishing areas, and in fjords. Marine mammal vocalizations were detected near the ice edge, at fjord mouths, and in fjords. This acoustic characterization study provides a glimpse into the sonic sources and balance of sounds in the soundscape at present, essential data as the region rapidly transforms.
Integrating ocean soundscape modelling and mapping into marine environment quality assessment and marine spatial planning
Authors: Aulanier Florian J. , Lebel Patrice , Simard Yvan
Published: July 2024

As on land, underwater anthropogenic noise and its potential impacts on marine ecosystems have been a growing concern in the past three decades. Initially focusing on louder noise sources, acute physical and behavioral impacts on marine mammals and commercial fish, governmental agencies started to integrate soundscapes into marine spatial planning. However soundscape science has to deal with a large number of metrics and variables (time, space, frequencies, species, types of impacts, sound sources,…) and uncertainties to be able to bring a scientifically robust and reliable support to decision making process. This is a real challenge to integrate and communicate to a vast diversity of stakeholders. To address this challenge, we present a study of the impact of shipping noise on the St Lawrence Estuary and Gulf ecosystems and in particular on endangered marine mammals. The methodology uses probabilistic underwater acoustic modelling to produce 3D-maps of acoustic-field statistics and risk of impacts at daily, weekly, monthly and annual scale over few year-cycles. Those maps are then fed into a web application capable of handling terabytes of geospatial raster’s which allows to produce statistics on user-defined area interactively in order to explore and support collaborative decision making process between marine spatial planner and stakeholders. Details on probabilistic methodology and practical examples will be shown, with concluding remarks on gaps and remaining challenges.
Solutions to muddy (geoacoustic inversion) problems
Authors: Bonnel Julien
Published: July 2024

Waveguide propagation is a ubiquitous topic in ocean acoustics. This presentation focuses on low-frequency (f < 500 Hz) sound propagation in coastal oceans (water depth shallower than 500 m). These environments are highly dynamical and complex, and act as dispersive waveguides, bounded by the sea-surface and the seafloor. The underwater acoustic field can thus be described by a set of modes that propagate with frequency-dependent speeds. Propagation of transient acoustic signals to a distant receiver (range > 1 km) accrues multi-modal dispersion information about the propagation medium. To extract relevant information about the oceanic environment from the acoustic recording, physics-based processing methods must be used. In this presentation, I will briefly review modal propagation and time-frequency analysis. I will then show how these approaches can be combined into a non-linear signal processing method dedicated to extracting modal information from a single receiver: this information is the foundation of a transdimensional inversion method used to characterize the oceanic environment. This method will be used to perform geoacoustic inversion on the New England Mud Patch. Using several datasets collected under different oceanographic conditions, I will notably demonstrate a successful estimation of the seafloor properties, consistent with geophysical core measurements and other inversion studies, even when the water column is dynamical and mostly unknown.
In vitro comparison of subharmonic-aided pressure estimation sensitivity among microfluidic monodisperse microbubbles, sonazoid, and definity
Authors: Kim Ga Won , te Winkle Lisa , van Hoeve Wim , Sarkar Kausik , Forsberg Flemming , Eisenbrey John
Published: July 2024

The subharmonic response of microbubble-based ultrasound contrast agents (UCAs) typically exhibits an inverse linear relationship with the surrounding ambient pressure. Although SHAPE has been clinically successful, the sensitivity of SHAPE at lower pressures is suboptimal. While previous studies optimized SHAPE using commercially available UCAs without considering their size distribution, in this study, two SHAPE-specific monodisperse microbubble (MMB) UCAs with different bubble diameters were compared with commercial polydisperse UCAs as well as their buoyancy-separated subpopulations. UCAs were imaged in a hydrostatic tank containing 350 ml of deionized water. The pressure within the tank was increased from 0–100 mmHg. Using a modified Logiq E10 scanner (GE HealthCare) with acoustic power optimization, SHAPE data was acquired using subharmonic imaging mode with a C1-6 curvilinear probe at 2.5 MHz (receiving at 1.25 MHz). After identification of the optimal acoustic output power, MMB with a mean diameter 1.66 mm demonstrated a mean SHAPE sensitivity of −0.207 dB/mmHg (r2 = 0.94). The second MMB with a mean diameter 3.45 mm demonstrated a mean SHAPE sensitivity of −0.300 dB/mmHg (r2 = 0.92). In contrast, this was 2.5–4 times more sensitive than the two polydisperse UCAs (slope range of −0.081 to −0.074 dB/mmHg) and 1.45–5 times more sensitive than the buoyancy-separated UCAs (ranging −0.061 to −0.142 dB/mmHg). These results suggest that SHAPE-optimized MMB are more sensitive to measuring changes in pressure.
Dosage dependent subharmonic response and ambient pressure sensitivity of sonazoid microbubbles for subharmonic aided pressure estimation
Authors: Yapar Mehmet , Azami Roozbeh H. , Forsberg Flemming , Eisenbrey John , Sarkar Kausik
Published: July 2024

Microbubbles are micron-sized contrast-increasing agents for diagnostic ultrasound imaging. At half of the excitation frequency due to nonlinear oscillations, they generate a subharmonic response, the magnitude of which changes by the ambient pressure. Subharmonic Aided Pressure Estimation (SHAPE) is a noninvasive method to measure local in vivo pressure utilizing subharmonic emission from microbubbles using medical ultrasound. In this study, we investigated the in vitro dosage effect of Sonazoid, a commercially available microbubble, on SHAPE. We subjected Sonazoid microbubbles to acoustic excitations ranging from 100 to 700 kPa peak negative pressure (PNP) and at a frequency of 3 MHz. We increased the ambient pressure up to 20 kPa and investigated the change in subharmonic signal during eight pressurizing-depressurizing cycles. We observed two different behaviors of subharmonic responses over investigated parameters. Subharmonic response increased significantly with increasing ambient pressure under low PNP excitations for sufficiently high concentrations. Meanwhile, increased ambient pressure at higher PNPs drastically reduced the subharmonic response for sufficiently low concentrations. Reported findings are crucial for characterizing the SHAPE performance of Sonazoid microbubbles, offering valuable insights for improved, consistent, and cost-efficient practice.
Extracellular matrix stiffness affects microbubble-assisted endothelial permeabilization under flow
Authors: Katz Zoe D. , Memari Elahe , Helfield Brandon
Published: July 2024

Cancer immunotherapy has faced challenges in the treatment of solid cancers due to the complex tumor microenvironment (TME), including physical barriers that prohibit immune cell infiltration. Ultrasound (US) stimulated microbubbles present a novel way to potentiate cancer immunotherapy in tumors by permeabilizing the tumor vasculature, however the effect of individual TME parameters on treatment efficacy has not yet been elucidated. Here, we focus on one biophysical parameter, showing that an increase in matrix stiffness increases US-assisted membrane permeabilization. Using a novel setup that allows for real-time visualization under flow, HUVECs seeded on polyacrylamide hydrogels of different stiffnesses (800 and 1600 Pa) showed an increase in sonoporation rates. Collagen models corroborate this trend at two different flow rates for a range of stiffnesses (5, 25, and 75 Pa): for both 5 ml/min and 30 ml/min, there is a relative increase in sonoporation from the stiffer substrate. For a given collagen substrate, there is a significant increase in sonoporation efficiency with increasing flow rate. These data can be used to fine-tune treatments according to different TMEs; further, our findings have applications in designing US parameters for targeted drug delivery and other clinical contexts that consider a variety of tissue stiffnesses.
Energy density source levels of underwater explosive charges
Authors: Chapman Ross
Published: July 2024

This paper presents experimental measurements of energy density source levels of small explosive charges for high frequencies to 18 kHz. The experiments were carried out using Signals Underwater Sound (SUS) charges deployed at a deep water site in a coastal fiord north of Vancouver BC. The waveform of an underwater explosion is characterized by a high intensity shock wave signal followed by a series of bubble pulses of decreasing intensity. The bubble pulses dominate the SUS energy density spectrum at frequencies below 1 kHz, but at higher frequencies the spectrum is dominated by the characteristics of the decay envelope of the shock wave signal. The explosive material in SUS charges is packed in a thin cylindrical cavity, resulting in a non-uniform decay envelope with secondary pulses when detonated, and a non-spherical distribution of the radiated sound. The impact of the cylindrical charge shape on energy density source level was investigated experimentally. Data were recorded for SUS deployments that generated in-line and broadside sound propagation to the receiver with respect to the axis of the cylindrical charge. Experimental measurements indicate significant differences in the high frequency SUS energy density spectrum depending upon the SUS and receiver geometry.
Modeling and development of a narrowband gas-combustion infrasound source
Authors: Smith Chad M. , Gabrielson Thomas B.
Published: July 2024

An invaluable tool in characterization of any receiver, propagation path, or detection system, is a source with known and repeatable signal characteristics. This talk will discuss development of a well-controlled narrowband infrasound source with frequency capabilities over the 0.1 to 10.0 Hz band. Design of a transportable sound source within this band is a difficult engineering challenge. The simple source equation, which will govern any portable infrasound source due to the long wavelengths, shows this fundamental difficulty. As frequency decreases, volume displacement must increase by the squared inverse factor of frequency in order to maintain an equal pressure at equal range. To combat this, the authors have developed a source system that uses gas combustion to displace large volumes in the open atmosphere using the gaseous and highly heated combustion constituents of propane and atmospheric oxygen. Measurements have verified the capability of generating narrowband signals with reasonable signal-to-noise ratio (SNR) over the full band at close range. Signals at 1 Hz have been measured with reasonable SNR to ranges greater than 2 km. Development of the infrasound source prototype, experimental measurements, and modeling of the acoustic pressure output will be discussed.
Teaching the basics of acoustics using smartphones
Authors: Robin Olivier
Published: July 2024

This communication proposes a basis for offering short introductions to the basic principles in acoustics, like adding decibels and the behavior of Helmholtz or quarter-wavelength resonators. The proposed approach combine mobile and experiential learning approaches using smartphone sensors and applications. The objective of these mobile laboratories is to complement, but not replace, traditional laboratories, which allow for more advanced learning in particular topics. However, the proposed series of experiments can be carried out autonomously; students can explore scientific knowledge in real-life situations and without time or place constraints. Indeed, generic or everyday places can be considered, contrary to traditional laboratories that have to be held in dedicated or specific premises.
Acoustic impedance measurement head design and evaluation
Authors: Darabundit Champ C. , Scavone Gary
Published: July 2024

Acoustic input impedance measurements are a useful tool for characterizing the behavior of a wind instrument. Methods for measuring acoustic input impedances include the two-microphone three-calibration (TMTC) technique (Gibiat and Laloë, 1990) and the multi-microphone method (Jang and Ih, 1998). We present and evaluate the design of a new impedance measurement head based on the multi-microphone method. We will discuss practical aspects such as impedance head calibration, measurement stimulus, and leak detection.
Microcavity-enhanced photoacoustic vibrational spectroscopy of single particles
Authors: Xiao Yun-Feng
Published: July 2024

Confinement and manipulation of photons using microcavities have triggered intense research interest in both fundamental and applied photonics for more than two decades. Prominent examples are ultrahigh-Q whispering gallery microcavities which confine photons using continuous total internal reflection along a curved and smooth surface. The long photon lifetime, strong field confinement, and in-plane emission characteristics make them promising candidates for enhancing light-matter interactions on a chip. In this talk, I will focus on single-particle photoacoustic vibrational spectroscopy using optical microcavities.
Laser-based resonant ultrasound spectroscopy for monitoring secondary phases in metastable Ti-alloys: From growth kinetics to high-throughput characterization
Authors: Seiner Hanus , Sedlak Petr , Janovska Michaela , Nejezchlebova Jitka
Published: July 2024

Metastable beta-Ti alloys undergo complex microstructural changes when annealed for extended times (hours, days, weeks) at temperatures below beta-transus. Contact-less RUS turns out to be a perfect tool for monitoring these processes, as well as for analyzing the properties of the alloys after the heat treatment. In the talk, we will illustrate this ability with three examples of recent advancements in this field. In particular, we will show that RUS is capable of analyzing (i) growth kinetics [1], from fast non-equilibrium phenomena to extremely slow processes; (ii) cubic symmetry conservation in single crystals with particles of various secondary phases [2]; and (iii) phase composition-elasticity relationships in series of oligocrystalline samples [3]. [1] Nejezchlebová et al. Elastic constants of β- Ti15Mo (2019) J Alloys Compounds, 792, pp. 960–967. [2] Olejňák et al. An ultrasound-based evaluation of cubic symmetry preservation and homogeneity in elastic behavior of β+ω and β+α Ti-alloys (2023) Materials and Design, 236, art. no. 112474. [3] Preisler et al., High-throughput characterization of elastic moduli of Ti-Nb-Zr-O biomedical alloys fabricated by field-assisted sintering technique (2023) J Alloys Compounds, 932, art. no. 167656.
Numerical extraction of three-dimensional acoustic polarizabilities for acoustically small scatterers
Authors: Lawrence A. J. , Wallen Samuel P. , Haberman Michael R.
Published: July 2024

Polarizability is a convenient descriptor for scattering from low-ka inhomogeneities in both electromagnetism, where it originated, and in acoustics, where it is increasingly used in the design of metamaterial elements. In two or three dimensions, the polarizability is represented by a block matrix that couples the local pressure and particle velocity fields to the lowest-order components of the multipole expansion, usually truncated to dipole order. A fully dense acoustic polarizability matrix has components that couple spatially uniform pressure and velocity oscillations to dipole and monopole scattering, respectively. This unique coupling leads to acoustic bianisotropy, also known as Willis coupling, for a collection of scatterers. The design of Willis materials necessitates computationally efficient methods to extract all components of the polarizability matrix and, at present, only two-dimensional analytical extraction methods are found in the literature. In this work, we present an algorithm to extract all components of the three-dimensional polarizability matrix from a scatterer with arbitrary geometry and composition. The method presented here is numerically efficient and yields results that are in agreement with an analytically obtained benchmark polarizability, providing a useful tool for acoustic metamaterial design.
Acoustic vowel distances within and across dialects
Authors: Clopper Cynthia G.
Published: July 2024

Regional dialects of American English exhibit variation in the phonetic realization of vowel categories. This variation leads to different degrees of phonetic vowel similarity within and across dialects. This vowel similarity has been captured by measures of formant distance and overlap in the acoustic space, typically with static formant estimates from a single timepoint in the vowel. In contrast, dialect similarity has been assessed using measures of acoustic distance over time. In the current study, dynamic measures of acoustic distance, including dynamic time warping, root mean-square distance, and generalized additive mixed effect models, were used to assess within-dialect vowel category distances and to compare these distances across dialects. The results were generally consistent across the different distance metrics, confirming their respective ability to capture acoustic vowel distance. However, the magnitude of the distances varied across dialects and vowel variables. Whereas some dialect-specific variables showed the expected patterns of within- and across-dialect similarity based on previous descriptive work, other variables did not. These mixed findings have implications for our understanding of regional dialect variation in American English, its effect on acoustic vowel similarity, and the relationship between acoustic vowel similarity and perceptual ambiguity of vowel contrasts within and across dialects.
Metrical segmentation across dialects
Authors: Warner Natasha , Moon Ki Woong , Park Seongjin , McQueen James M. , Albusairi Mohammed K.
Published: July 2024

Norris, McQueen & Cutler (1995) tested the Metrical Segmentation Strategy (MSS; Cutler & Norris, 1988) as part of the spoken-word recognition model Shortlist, using British English stimuli and listeners. We replicate their study using American English listeners, who we exposed to one of two sets of stimuli. One group heard a new set of stimuli recorded in American English, while the other was exposed to the original British English recordings. Norris et al. used a word-spotting task: listeners had to spot words within speech (e.g. “stamp” in [stæmpɪdʒ]). Target words were CVCC (like “champ") or CVC (like “done"), and were followed by a full vowel (e.g. /tʃæmpoʊʃ/) or a reduced vowel (e.g. /tʃæmpəʃ/). The original study found different behavior for CVCC versus CVC targets, with the results suggesting that listeners hypothesize a word onset at the start of a full-vowel strong syllable (the MSS). The results for the current study with American stimuli partially replicate the original findings, showing even more consistent support for the MSS. The results with British stimuli also support the MSS, but with higher error rates. The results indicate that the MSS has a very strong effect even in the difficult setting of cross-dialectal perception.
Efficient methods for iterative ultrasound image reconstruction using L1 and L2 norm regularization
Authors: Jakovljevic Marko , Biondi Ettore , Samir Anthony E.
Published: July 2024

Ultrasound image reconstruction can be posed as an inverse problem, with image pixels as parameters to a model of wave propagation that are estimated from raw ultrasound channel data. Such framework allows one to make assumptions about channel signals and image properties in form of regularization that can be used to improve reconstruction accuracy in the presence of electronic and acoustic noise. A simple model assumes spherical wave propagation from point sources in a homogeneous medium, similar to delay-and-sum (DAS) beamforming; solving such problems numerically can require many iterations and can result in blurred images when traditional L2 norm regularization is used. We use Fast Iterative Shrinkage Thersholding Algorithm (FISTA) to reduce the number of iterations to less than 10, and to apply L1-norm regularization to the data, which improves edge sharpness and image contrast. We demonstrate the concept using FIELD II simulated ultrasound signals from point, speckle, and anechoic targets with controlled levels of electronic and speckle noise. The FISTA-reconstructed point targets show reduced sidelobe levels by 15 dB compared to the traditional DAS image, and the reduction in full-width at half maximum by a factor of 2. We also implement iterative reconstruction in omega-k frequency domain, which allows factoring the forward and adjoint operators at each spatial frequency and paves the way for an intuitive and more memory efficient, multi-threaded implementation of the method.
Biogeoacoustic variability in muddy ocean bottom sediment
Authors: Lee Kevin M. , Ballard Megan , McNeese Andrew R. , Venegas Gabriel R. , Chaytor Jason , Dorgan Kelly M. , Wilson Preston S.
Published: July 2024

Both physical and biological benthic processes can influence seabed heterogeneity and contribute to spatiotemporal variability in geoacoustic properties. In particular, how biological processes affect both sediment acoustic properties and their variability is poorly understood. To address this deficiency, recent measurements investigated spatial variability in the upper few decimeters of sediment near the water-seabed interface within a fine-grained sediment deposit on the New England shelf. At each measurement location, acoustic probes were inserted into the sediment to collect direct in situ measurements of sediment sound speed and attenuation at near-ambient conditions, after which cores were collected from the inter-probe propagation paths for ex situ analysis of sediment physical, biological, and acoustic properties. Relationships among sediment properties, such as bulk density, porosity, grain size distribution, organic matter composition, infaunal community composition, and acoustic measurements spanning several frequency decades (10–1000 kHz) will be explored in this paper. Frequency dependence of sediment acoustic properties will also be discussed in the context of sediment acoustics models for mud based on the viscous grain shearing and extended Biot theories. [Sponsored by ONR.]
Jerry Christoff’s contribution to the development of performing arts acoustical design practices
Authors: Lo Verde John , Rawlings Samantha , Dong Wayland
Published: July 2024

In the 1960s, Jerry Christoff, alongside Paul S. Veneklasen, performed research and development into acoustics for performing arts spaces. Some of the practices developed by these researchers are precursors to modern-day design metrics, as they looked at lateral reflections and source strength, to name a few. Small-scale models of performance spaces were being constructed with an ultrasonic source to better understand and visualize how sound waves behave within a performance space. This presentation will be focused on Jerry’s contribution to science with regard to the design of performing arts spaces.
Perceptual study on combined real-time traffic sound auralization and visualization
Authors: Dreier Christian , Rehman Rouben , Meier Niklas , Fiebig Andre , Vorlaender Michael
Published: July 2024

Auralization is a promising approach for future application in urban planning including noise aspects. From a technical point of view, auralization of the urban environment is challenging due to the high number of sound sources, time-variant and inhomogeneous atmospheric conditions and the large scale of scenarios. This work presents the modeling and computationally efficient implementation of traffic sound sources and its integration to a complex urban scenario with real-time auralization. Furthermore, it presents results from a perceptual study whose immersion is enhanced by presenting a coupled visualization of the scene to the participants by using a head-mounted display. Whereas the experiment on the one hand comprises virtual reality-related aspects considering the assessment of immersion and plausibility of the scenario, on the other hand it covers the assessment of individual noise events in the urban soundscape. The experiment focuses on acoustically prominent noise events, such as particularly loud and harsh sources, or resulting from specific driving behavior. The results are discussed in the foreground for further improvements for audio-visual simulations of the urban environment.
Architectural acoustics short course presentation material
Authors: Hoover K. Anthony , Good Kenneth W.
Published: July 2024

The Technical Committee on Architectural Acoustics (TCAA) is a Registered Provider in the American Institute of Architects (AIA) Continuing Education System (CES). The TCAA has developed a standardized introductory short course for architects called “Architectural Acoustics,” An architect can earn one continuing education unit (CEU) by attending this short course, if presented by a qualified member of TCAA. The course covers topics in sound isolation, mechanical system noise control, finish treatments, and implementation of quality acoustical spaces. This paper will cover the course material in order to prepare and qualify potential presenters. In order to qualify as an authorized presenter for this AIA/CES short course, attendance at this special session and membership in TCAA are required.
Marine soundscape monitoring from underwater autonomous vehicles—Passive acoustic monitoring gliders
Authors: Cauchy Pierre
Published: July 2024

Ocean gliders are buoyancy-driven autonomous underwater platforms, able to collect oceanographic measurements along vertical profiles during multi-months missions, covering thousands of kilometers. They glide quietly through the water column without propulsion noise and are therefore extremely suitable for Passive Acoustic Monitoring (PAM) of the marine environment. From PAM glider data in the Mediterranean Sea and the Southern Ocean, we illustrate the current and potential uses of PAM gliders for the study of physical oceanography, biology, ecology and for regulatory purposes. We evaluate limiting factors for PAM glider survey, such as platform-generated and flow noise, instrument size and power constraints, profiling ability and movement of the platform. We provide recommendations and good practices for typical PAM glider surveys and present future developments identified by the PAM glider community to further develop the readiness level and societal impact of PAM glider observation: (1) Calibration of the PAM glider to collect absolute sound levels; (2) adapted sampling methods and statistical analysis techniques to perform population density estimation; and (3) Integration of PAM glider observation to existing monitoring programs.
Cooperative-hydrophone-based underwater soundscape monitoring in a bustling harbor enhanced by coral ecosystem
Authors: Liu Ben , Xu Wen
Published: July 2024

Anthropogenic underwater noise is an emerging pollutant, urging a focus on studying the spatial and temporal dynamics of underwater soundscapes for effective environmental protection. This study centers on a bustling harbor enriched by coral ecosystems, employing 5–8 spatially distributed bottom-mounted passive acoustic monitoring (PAM) nodes strategically placed at locations of interest with diverse natural conditions and ship traffic intensities. Focused on the intricate interplay between anthropogenic and natural contributors, including shipping traffic and coral ecosystems, one-third octave band sound pressure levels SPLs were calculated and analyzed at different frequencies, revealing significant variations in levels across different times and locations. Diurnal variations in ambient noise levels highlight the complex relationship between human activities and marine ecosystems. Higher and more variable SPLs, primarily related to shipping traffic, were recorded during the daytime, while lower SPLs, accompanied by increased fish sounds, were observed at night. The collaborative deployment of multiple hydrophones enables an estimation of noise source direction, and multi-hydrophone based principal component analysis (PCA) for dimensionality reduction and subsequent clustering methods were used for noise source classification. This study significantly contributes to the field of underwater noise monitoring, offering a holistic perspective on busy harbor environments.
Active learning algorithms for autonomous platforms to characterize underwater static acoustic sources
Authors: Jandial Prajna , Zhu Frances , Nosal Eva-Marie
Published: July 2024

Integrating passive acoustics with autonomous platforms presents an opportunity to complement the spatial constraints of traditional fixed sensor methods by leveraging the capacity of autonomous underwater vehicles (AUVs) to make real-time decisions. We present algorithms that adaptively sample a survey region based on the sound field characteristics. These algorithms use an active learning strategy based on Gaussian Process (GP) regression to characterize a static sound field in a survey region. With each location sampled, the algorithms employ a GP to estimate the distribution and quantify the uncertainty of static acoustic sources within the region. The uncertainty metric is used to then choose the next sampling location. This dynamic approach not only maximizes the information gained by the AUV at every location that it samples but also ensures an efficient convergence toward the true distribution of underwater static sources in that region. These algorithms were developed in simulation and will be tested in controlled experiments.
Investigation of the ultrasound-mediated toxicity mechanisms of IR780 iodide
Authors: Singh Kritika , Vasilyeva Alexandra , Hu LuNa , Ruan Jia Ling , Gray Michael , Schiller John , Stride Eleanor P.
Published: July 2024

IR780 iodide is a lipophilic cation heptamethine dye that has emerged as a potential fluorescent probe for in vivo tumor imaging. Previous work has shown it to be a sono- and photo-sensitizer (sound- and light-activated molecule) suitable for use in sonodynamic therapy (SDT) due to its proposed ability to produce ROS when ‘activated' by ultrasound. This study evaluated IR780 iodide as an SDT agent in vitro using A549s, HeLas, and HeLa S3 cell lines, a broad range of ultrasound and light parameters, multiple ultrasound and light systems, and with and without cavitation nuclei. Through temporal uncoupling of ultrasound application and compound administration in vitro and in vivo, evaluation of cavitation-only related cell death, assessment of the dark toxicity of IR780 iodide, and development of positive controls for cell permeabilization (sonoporation), this study shows that dark toxicity and cavitation play an important role in IR780 SDT-induced cell death. This potentially explains the high levels of cell death observed for comparatively low concentrations of ROS. Additionally, this study proposes a standard set of controls for SDT mechanistic studies, which were used to further help study the mechanisms of other SDT drugs including Rose Bengal, 5-aminolevulinic acid, and indocyanine green.
What’s that sound? Real world observations as teaching opportunities
Authors: Case John A.
Published: July 2024

In our day-to-day lives, we encounter numerous interesting acoustic events that can offer a starting point for a rich learning experience. In the past, making recording and performing signal analysis took expensive equipment and expert knowledge. Now, smart phones offer a readily available measurement tool to capture interesting phenomena in the world around us. A simple phone video file can provide audio for introducing signal processing techniques as well as a motivating visual context, and readily available signal processing tools enable for the investigation of these events. Several examples of such events will be presented and discussed. These examples are used as a motivation for discussion and signal processing analysis, trying to uncover the underlying physics behind each example.
Physical modeling and time-domain simulation of a piano
Authors: Tominaga Eiji , Sato Masanao
Published: July 2024

The elaborate method to simulate the sound produced by a piano is presented, using the physical model that considers almost all parts of the piano with wood complex elastic orthotropy and manufacturing stress, but excluding action parts. The purpose of this work is to improve the efficiency of piano development by clarifying the causal relationship between the design and the produced sound. The completed piano is modeled as a 3D coupled system consisting of “nonlinear systems including hammers and strings” and “a linear coupled body-air system.” The hammer felt property are represented by the double layer nonlinear generalized Maxwell model. For the strings with geometrical nonlinearity and their support end anisotropy, the Galerkin method with the component mode synthesis (CMS) method is applied. And also, for the large-scale linear coupled body-air system, the complex CMS method via nonlinear eigenvalue analysis is used. The simulated sounds, including the ringing and body sounds, are so realistic that they help piano designers predict the actual sounds before making heavy prototypes. The method presented here can be applied to other musical instruments that consist of strings and a body, such as guitars and violins.
Towards better copies of guitars: Compensate material variability with geometry
Authors: Cillo Pierfrancesco , Ziegler Pascal , Eberhard Peter
Published: July 2024

Luthiers have been trying to copy the sound of iconic instruments like Torres guitars for many years. Though precise geometric copies were manufactured, audible differences were found which can be attributed largely to the natural variability of wood. We were able to present a methodology allowing non-destructive material identification based on which a shape optimization was performed to compensate material variablility with specific geometric variations, allowing a much more exact copy of a guitar soundboard in terms of eigenfrequencies. We will present a generalization of this methodology to full guitars including almost arbitrary geometric adaptions and consideration of mode shapes in the optimization. A mesh morphing strategy allows to simultaneously define very general geometric adaptions and comparing mode shapes without re-meshing. Further, a parameterized reduced order numerical model will be presented in which all possible global geometric variations are mapped to the individual elements of the underlying finite-element model in symbolical form. This symbolical representation is then carried over to the assembled finite-element matrices resulting in an extremely efficient reduced model keeping the symbolic relationships. This is the absolute core requirement of an efficient shape optimization. The approach will be presented for hexahedral elements.
Survey of background noise levels inside classrooms on a college campus
Authors: Ruhala Laura , Ruhala Richard J. , Patino Antonio , Packer Charles
Published: July 2024

Sound level measurements were made for 18 classrooms and learning spaces on the Marietta Campus of Kennesaw State University, Georgia, USA. Excessive background noise in learning spaces diminishes the speech intelligibility from the speaker to the listeners. The noise measured was in empty or nearly empty classrooms with no one talking. The primary background noise source was observed to be due to heating, ventilation, and air-conditioning equipment. The results are compared with a student survey to see if the noise complaints correlate with the noisiest classrooms in terms of their average A-weighted decibel levels. In addition, conformance with ANSI-ASA S12.60-2010/Part 1 (Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools) is evaluated.
Case study of construction noise and vibration monitoring at an elementary school
Authors: Wong Galen
Published: July 2024

Construction noise and vibration monitoring was performed for long-term construction activities occurring directly adjacent to an elementary school and playground area. Noise and vibration limits were determined based on measurements taken indoors and outdoors during preliminary construction activities, and in discussions with the school. Noise and vibration alerts during monitoring were provided in real-time to the construction managers during the activities, and notices of exceedances provided as methods of administrative controls. Various temporary noise mitigation barriers erected on-site were also assessed.
Air-coupled ultrasound for testing of batteries and components
Authors: Gomez Alvarez-Arenas Tomas
Published: July 2024

This work describes the use of an air-coupled and through transmission ultrasonic (0.2–1.5 MHz) technique, both at normal and oblique incidence, for the characterization and test of pouch-cell Li-ion (and similar types) batteries and components. Time domain measurements show that it is possible to measure ultrasonic velocity in the battery. Frequency domain measurements reveal the generation of thickness resonances. From them, solution of the inverse problem permit to extract: ultrasound velocity and attenuation (and variation with frequency), thickness and density. At normal incidence, these resonances provide information about the compressional wave. At oblique incidence, it is first observed that there is a range of incidence angles where propagation is no permitted. This response can be explained in terms of the battery layered structure, once these angles are exceeded, the shear wave is generated, propagated and observed, giving rise to the generation of thickness resonances. Shear wave propagation is strongly anisotropic: lower velocity in the direction of the battery plane, compared with a higher velocity in the direction normal to the battery plane. No limit angle for the shear wave is observed. Possibilities of this technique for the testing of new batteries, continuous state monitoring and battery sorting for re-use or recycling are discussed.
Cryogenic acoustic microscopy and evaulation of electronic components
Authors: Doran Steven , Bond Leonard J. , Barnard Daniel , Poonthottathil Navaneeth , Weinstein Amanda , Feng Yue , Edayath Sijith , Sogarwal Hariom , Krennrich Frank
Published: July 2024

Electronics operating at cryogenic temperatures are essential in fields like space exploration and particle physics. The Deep Underground Neutrino Experiment (DUNE), a next generation particle physics experiment, will rely on tens of thousands of custom designed application specific integrated circuits (ASICs) operating directly in liquid argon (87 K) for decades without repair or replacement. Ensuring circuit functional reliability throughout the duration of the experiment is mission critical. Both functional and nondestructive testing are employed to safeguard circuit quality and reliability. Part of this work involves the design, testing, and data analysis of a cryogenic acoustic microscope (CryoSAM) operating at 15 MHz. The CryoSAM is capable of interrogating ASICs at both room temperature (300 K) and in liquid nitrogen (77 K), identifying acoustic anomalies likely arising from thermal stress and manufacturing-related defects, using a powerful correlation analysis technique. These anomalies can lead to functional degradation and suboptimal electronic performance of the circuit sensors. Image analysis and correlations are used to compare differences seen before and after cryogenic temperature cycling. Data are reported that were collected at both room temperature and when cooled using liquid nitrogen. Designs and challenges of operating the instrument at cryogenic temperatures are also discussed.
Probing layer interface behavior in Lithium-ion batteries via concurrent ultrasonic and modal measurements
Authors: Litvinov Alexandra , McGee Tyler , Ezekoye Ofodike A. , Haberman Michael R.
Published: July 2024

Lithium-ion batteries are pivotal in various technological applications, from powering electric vehicles to supporting renewable energy storage systems. Understanding and monitoring the intricate chemo-mechanics within lithium-ion cells is imperative for ensuring their reliability and performance over time. Previous research has shown that both ultrasonic and vibrational measurements provide a measure of a cell’s state of charge (SOC) and state of health (SOH) and provide indications of existing or previous thermal or electrical abuse. Recent work suggests that ultrasonic and modal analysis may provide complementary insights into the evolution of layer interfaces during early-life aging due to charge-discharge cycling [J. Acoust. Soc. Am., 154, A284 (2023)]. This work presents the results of concurrent ultrasonic and modal measurements over multiple charge-discharge cycles. Namely, we monitor concurrent changes in the ultrasonic time-of-flight and signal amplitude and the resonance frequency of a clamped-clamped 10 Ah Nickel–Manganese–Cobalt pouch cell as a function of electrical cycling. The evolution of these metrics paired with analytical and numerical models of the cell will be used to understand changes in the material properties at layer interfaces and potential structural alterations within the battery which may be important indicators of SOC and early-life aging mechanisms.