bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling nonlinear acoustic damping due to flow separation
Authors: Day Joseph , Quinlan J. M.
Published: November 2022

Nonlinear acoustic damping has been observed in many high-amplitude acoustic systems as a result of flow separation and shear layer vortical motion, eventually transforming some of the acoustical energy into heat. The amount of nonlinear acoustic damping helps determine the nonlinear limit cycle amplitude, e.g., damping caused by baffle blades in a liquid rocket engine to reduce combustion instabilities. The damping mechanism is dependent on both the location and phase of flow separation. Identifying the flow separation is a function of both the boundary layer growth and the acoustically imposed pressure gradient. When the acoustic pressure gradient is adverse, the boundary layer is more prone to separation. Using this as a basis, a model can be created that is applicable to general geometry, which will then be used to approximate the nonlinear acoustic damping in various situations. The constructed model will be compared to established cases, such as an orifice in a duct, to validate the model.
A finite difference approach to study the impact of boundary conditions on the acoustical behavior of particle stacks
Authors: Mo Zhuang , Song Guochenhao , Shi Tongyang , Bolton J. S.
Published: November 2022

The responses of particle stacks to incident sound waves show interesting features that are very different from those of a homogeneous continuum. Further studies of the acoustical performance of particle stacks can help both to discover potential noise control applications of these types of materials, and to help provide better insight into the internal status of the particle stacks. In the current study, a finite difference (FD) model for a particle stack was built based on the Biot poro-elastic theory. The intention in developing this model is to describe the acoustical behavior of particle stacks with consideration of not only the finite stiffness of the particles, but also the influence of gravity and friction between the particles and the inner wall of their enclosure: i.e., the cylindrical sample holder of a standing wave tube, in this work. The derivation of governing equations and boundary conditions is introduced, together with acoustic measurement results of particles stacks consisting of micron-scale glass bubbles, including absorption coefficients and surface impedances that are compared with the theoretical predictions. The possible application scenarios of such materials, and potential developments that will further improve the FD model will also be discussed.
Characterizing flow conditions of urban environments from wind-induced noise measurements: A semi-empirical wind noise model of the University of the District of Columbia campus
Authors: Mandjoupa Lirane , Gaye Samba , Davis Dorian , An Justin , Mahmoud Wagdy , wang lei , Denis Max
Published: November 2022

In this work, the flow conditions within the University of the District of Columbia (UDC) urban campus are predicted from wind-induced noise. Wind-induced noise obtained from a collection of spatial distributed microphones are used to estimate the mean velocity airflow and wind noise distribution across the UDC campus. Wind speed and direction are estimated by fitting the second-order statistics of semi-empirical models of wind noise distribution from microphone measurements to analytical models in the least squares sense. The accuracy of the proposed is investigated for average microphone separation and time resolution. Comparisons of the wind speed and direction results to ultrasonic anemometer measurements are discussed.
Scanning Doppler LIDAR wind profiles to inform near shore atmospheric acoustic propagation modeling
Authors: Vecchiotti Andrea , Blackburn Hannah , Kirian Kyle , Vignola Joseph , Turo Diego , Foeller Jeff , Ryan Teresa J.
Published: November 2022

This work presents a comprehensive experimental system to measure concurrent atmospheric acoustic transmission loss and meteorological conditions. A three-dimensional scanning Doppler lidar wind profiler captures real-time wind speed gradients at many locations along the acoustic propagation path of a simple pitch catch style study. A long-range acoustic device on an anchored pontoon sends known chirp sequences to a seven-channel receiver array at the water’s edge at ranges up to approximately one kilometer. Additional synchronized meteorological observations include temperature, humidity, and wind measured with anemometers. The meteorological data stream is used to inform the sound speed gradient implemented in a parabolic equation based numerical model of atmospheric acoustic propagation. The model can account for sea surface roughness and accommodate a sound speed profile that changes along the propagation range. Model predictions are compared to measured transmission losses. An assessment of the value of the computational cost of incorporating the varying sound speed profiles in the model is presented.
Concurrent visualization and analysis of acoustic, flesh-point motion, and electroglottography signals during speech production
Authors: Goel Jessica , Masapollo Matthew , Lee Yoonjeong , Wayland Ratree
Published: November 2022

Over the years, technological advances have enabled speech researchers to directly track the skilled, sound-producing movements of the vocal tract, both intraoral and laryngeal articulators normally hidden from view (the tongue, velum, and glottis) and orofacial articulators directly visible on talkers’ faces (the lips and jaw). Despite these advances, however, no single instrument is capable of concurrently recording movements of all the articulators, which has impeded progress in characterizing inter-articulator control and coordination. To explore how inter-articulator coordination subserves linguistic structure, tools that co-register and temporally align different signals from different recording devices are necessary. This tutorial introduces optimal methods for studying the temporal coordination between laryngeal, intraoral, and orofacial articulators by combining various signals from electromagnetic articulography (EMA), electroglottography (EGG), and audio recordings, and displaying the time-aligned signals in the same analysis space. The multimodal data is processed using a set of MATLAB-based functions, which co-register and display positional and velocity trajectories of the lips, tongue, and jaw in tandem with the EGG waveform, F0 trajectory, and acoustic waveform and spectrogram. The coordination of laryngeal and supralaryngeal speech movements can then be measured and analyzed. [Work supported by an Emerging Research Grant from the Hearing Health Foundation.]
Extending the pixel difference metric from 2D to 3D/4D ultrasound
Authors: Palo Pertti , Lulich Steven M.
Published: November 2022

It is frequently of interest to examine differences (e.g., the 1st or 2nd difference) in signals and images. Differencing can be employed for the detection of edges in images, or the detection of events in temporal sequences. One such event is the onset of articulatory movement in ultrasound image sequences of the tongue. It has been quantified using a form of Euclidean distance between successive frames of image scan line data, referred to as Pixel Difference. When applied to 3-D/4-D ultrasound data of the tongue (after scan conversion), Pixel Difference exhibited a surprisingly poor signal-to-noise ratio. In this presentation, we test the hypotheses that (1) scan conversion amplifies the effect of speckle noise near the top of the ultrasound image (i.e. above the tongue), and (2) the Pixel Difference signal-to-noise ratio in 3-D/4-D ultrasound differs from 2-D ultrasound by a power of 3/2 due to the added spatial dimension.
Evaluation of automatically generated tongue surfaces from three-dimensional/four-dimensional ultrasound recordings of sustained vowels
Authors: Lulich Steven M. , Patel Rita R.
Published: November 2022

Three-dimensional/four-dimensional (3-D/4-D) ultrasound is capable of imaging almost the entire tongue surface during the production of speech sounds, including sustained vowels. Manual tongue surface segmentation is slow and laborious, but typically yields good results. Automatic tongue surface segmentation is much faster and objective but can result in errors. In this presentation, we quantify the errors in a set of tongue surfaces that were automatically segmented using the previously published 3D-SLURP algorithm implemented in the WASL toolbox for MATLAB. The ultrasound recordings were of 20 children and 40 adults producing the sustained vowel [o:] with and without a narrow straw semi-occlusion in the mouth. Twenty of the 40 adults produced phonation at threshold phonation. Automatic and manual error detection and quantification methods will be compared to evaluate the accuracy of the automated algorithm when applied to the sustained vowel [o:]. [Work supported in part by NSF.]
Modeling retroflex fricative variation in accented mandarin
Authors: Wang Fenqi , Deng Delin , Wayland Ratree
Published: November 2022

Since dental-retroflex fricative contrast is not consistently maintained in many southern dialects of Chinese, native speakers of these dialects may not accurately produce the Mandarin retroflex fricative /ʂ/. Consequently, /ʂa/ may be realized as [sa] (Duanmu, 2007). This study investigated the variation of the retroflex fricative /ʂ/ in a Chinese Mandarin speech corpus (DataTang, 2018). The corpus contains 200 hours of recordings of 600 speakers from different dialectal regions in China. Each recording was aligned at the phone level using Montreal Forced Aligner. The center of gravity of the acoustic energy (COG) of the target sounds was extracted using Christian DiCanio’s Praat script. For statistical analysis, the generalized additive mixed-effects model (GAMM) was used. COG was the response variable. The following vowel’s height, tone, and gender were factorial predictors. To evaluate the geographic effect, we used tensor product smooths by fricatives with the longitude and latitude of each speaker’s birthplace (Chuang et al., 2021). Our results suggested a more dental-like realization of the retroflex for speakers from southern China and significant effects of the following vowel’s height and gender in the realization of Mandarin retroflex fricative.
TSUNet: Transformer-based single channel speech enhancement using SkipConv U-Net for cochlear implant (CI) users
Authors: Mamun Nursadul , Hansen John H.
Published: November 2022

The presence of multi-speaker babble noise greatly degrades speech intelligibility for communications with cochlear implant (CI) users. Convolutional Neural Network (CNN) based speech enhancement has been popular for suppressing noise because it can localize spectro-temporal information within the feature set. However, suppressing noise without creating artifacts is challenging in low SNR environments, and even more so if the noise is speech-like such as Babble noise. Transformers have emerged as a useful architecture with innate global self-attention mechanisms to capture long-range dependencies and global context, which is a limitation for CNN. The Mel spectrogram has a strong correlation along both time and frequency axes, and thus captures contextual information beneficial for speech enhancement. In this study, we propose TSUNet, which leverages both Transformers and U-Net to capture sufficient low-level details of contextual information in the speech time-frequency domain. TSUNet employs Transformer layers at the bottleneck of CNN based on U-Net. We also incorporate a neural vocoder to synthesize speech from the time-frequency representation without using a contaminated phase. The performance of the proposed network is evaluated under simulated and real recordings of noisy speech including CI testing. The proposed network achieves very effective performance in both scenarios.
Image enhancement by motion compensation of a moving array for underwater target detection
Authors: Kim Sea-Moon , Lee Pan-Mook , Choo Yeon-Seong , Byun Sung-Hoon
Published: November 2022

Recently synthetic aperture sonar is widely used for precise seafloor exploration or underwater target detection. In order to acquire clearer sonar images, accurate measurement of the platform motion is absolutely required. Various approach has been studied for the motion estimation and compensation for sonar image generation. A tank test for underwater target detection has been done using an array mounted on a vertical bar attached on a horizontally moving platform. The array was vibrating when moving and the motion was measured using asynchronous navigational sensors installed just beside the array. In this study images constructed by synthetic aperture processing before and after motion compensation are compared. Across track array movement as well as translational motion with tilt angle was applied during the experiment. Additional numerical analysis of target detection with various motion parameters are performed. The effect of the motion estimation error and the installation offset are also analyzed. [This work is financially supported by the research project PES4380 funded by KRISO.]
Parabolic completions in gibbon duets may signal appreciation of projectile motion
Authors: Schruth David M.
Published: November 2022

Most gibbon species produce salient duet calls at daybreak. Duets start with low frequency barks by males, followed by the female great call, and end with a short, and often complex, male-dominated coda. The female great call itself typically climaxes via a crescendoing increase in pitch, tempo, or both and characteristically features bilaterally symmetrical parabolic structures, which can manifest both in the distribution of vocal units over time as well as in frequency. Male codas appear to anticipate and even complete many of these female-initiated parabolas. Employing spectrograms of species-typical great calls from nearly all gibbon species (n = 12), I plotted coordinates of the upper-most frequency of each vocal unit. Using these x = time and y = frequency coordinates (plus x-differences), I tabulated the parabolas with the best possible second order polynomial fits for each species’ great call. Measures of parabolic fit for each call were then compared to quantitative locomotor estimates for each species. All forms of parabolic assessment had positive correlations with leaping bout percentages across species. These results indicate that gibbon duets may function to signal a fundamental understanding of parabolic shapes—presumably useful in landing airborne locomotor (especially leaping) bouts spanning canopy elements—enabling concordant execution of arboreally projectile acrobatics.
Wind-driven ambient noise in seasonally ice-covered waters north of the Svalbard Archipelago
Authors: Tollefsen Dag , Buen Helge
Published: November 2022

This paper presents analysis of a one-year (2018–2019) recording of ambient noise (40–2000 Hz) at a seasonally ice-covered location on the continental slope between the Svalbard archipelago and the Nansen Basin, northeast Atlantic Arctic. Time series of ambient noise show highest correlations with ice concentration and wind speed. A log-wind speed regression model is fitted to spectral noise data for three categories of ice concentration. Wind-speed dependence decreases with increasing ice concentration and increases with frequency, except at high ice concentration. Periodicity in noise during the ice-covered season is related to the M2 and M4 tidal current constituents.
Acoustic networks in high Arctic Ocean observing systems
Authors: Sagen Hanne , Dzieciuch Matthew , Storheim Espen , Stallemo Astrid , Langehaug Helene R. , Worcester Peter F. , Sandven Stein , Krishfield Richard A. , Colosi John A.
Published: November 2022

Sustained in situ ice-ocean observations are sorely lacking in the Arctic, limiting research on climate, weather, ice-ocean processes, and geophysical hazards. A sustained network of advanced multipurpose underwater moorings and drifting buoys in the Nansen and Amundsen Basins that included acoustic and other instrumentation would make a substantial contribution to a high Arctic Ocean observing system. Such a network would provide point measurements of ocean parameters, large-scale temperature measurements using acoustic thermometry, acoustic geo-positioning of underwater floats and gliders, and passive acoustic measurements for detection of marine mammals, geohazards, and human generated noise. Optimal design of such a network of fixed moorings and drifting platforms requires accurate knowledge of the ice-ocean environment to determine the acoustic properties. Such a sustained network would build on the successful basin-wide coordinated arctic acoustic thermometry experiment (CAATEX). In this presentation, the focus will be on the oceanographic and acoustic characteristics of the Nansen and Amundsen Basins using observations made during CAATEX. The ability of several climate models and reanalysis products to describe the oceanographic characteristics as well as their usefulness in predicting low-frequency acoustic propagation will be evaluated.
New developments in submarine cable technology can facilitate acoustics in Polar regions and on the global scale
Authors: Howe Bruce M. , Sagen Hanne
Published: November 2022

The subsea telecommunications cable industry is expanding their present single purpose infrastructure to include ocean observing capability. Science Monitoring And Reliable Telecommunications (SMART) Subsea Cables is working to integrate temperature, pressure, and seismic acceleration sensors into commercial cables (∼70 km spacing) to support climate and ocean observation, sea level monitoring, and tsunami and earthquake early warning on the global scale. Furthermore, telecom rated branching cables with power feed units supporting multipurpose “nodes” are becoming a reality. Acoustic capability can be integral to both. Major uses of these nodes include supporting low frequency transceivers enabling basin scale tomography and geo-positioning of mobile assets and docking for autonomous undersea vehicles (AUVs). Enabled by cabled power, these would be part of the fixed/mobile acoustic tomography system measuring ocean heat content at the speed of sound and more generally for transporting energy, data, and acquiring multidisciplinary data throughout a large volume of the ocean. Both variants and hybrids between can support the necessary acoustics contribution to ocean observing. Two proposed systems can support polar applications: Far North Fiber Express connecting Norway/Finland/Ireland with Japan via the Canadian Northwest Passage, and the NSF proposed SMART cable connecting New Zealand with McMurdo Base, Antarctica.
Endoscopic photoacoustic with deep learning for evaluating early detection of the gastrointestinal
Authors: Ou Ruei-Wen , Lin Wei-Cheng , Liu Hsiao-Chuan , WU JIAN-XING
Published: November 2022

Colorectal cancer is increasing rapidly every year. At present, traditional medical endoscopic probes are large in size, slow in imaging, and insufficient resolution. Here, we propose a system combining a customized probe-based photoacoustic system with deep learning to improve photoacoustic hardware to achieve a smaller size of the probe and a higher imaging resolution. On the other hand, deep learning was imbedded into the proposed photoacoustic system to achieve highly accurate results of the classifications for potentially helping physicians to identify lesions as the second opinion. In this study, a customized probe with a diameter of 9 mm was used to replace the original probe with a diameter of 1 cm in the hospital. The laser provides 15 W average power with an approximate 300 μJ pulse energy. The laser beam is formed by the lens after focusing, and the fiber couple can convert the light into parallel light. After the probe rotates 360°, a slip ring will trigger the ultrasound to receive particle displacements caused by the thermal propagations. A GRIN lens with a diameter of 1 mm was used to focus the scattered light. The proposed system can generate an 800 μm resolution. The collected images are classified by deep learning algorithms, including AlexNet, GoogLeNet, and ResNet, to differentiate polyps from tumors. After comparing these four image classification methods, ResNet_18 is finally used for image classification, which helps the attending doctor reduce fatigue and quickly identify a disease.
Ultrasound strain elastography-based characterization of in vivo breast lesions using deep learning
Authors: Jiang Jingfeng , Xu Zhengfu
Published: November 2022

Ultrasound strain elastography showed great promise for breast lesion characterization. With the readily available computational power in the clinical workflow, machine learning-based is gaining acceptance in cancer imaging applications. In this study, we combine the latest developments in motion tracking that enables us to obtain high-quality axial strain and full shear strain images to test the deep-learning-based prediction of breast lesion malignancy. To our knowledge, total shear strain images have not been widely used for breast lesion differentiation. More specifically, a PDE-based regularization method [Guo et al., Ultrasonic Imaging (2015)] developed by our group has been improved to get high-quality two-dimensional displacement data. From those high-quality displacement data, total shear strain images can be constructed. We adopted three variants of convolution neural network (CNN) models with attention modules to predict breast lesion malignancy by combining B-mode, axial strain, and total shear strain images and their radiomic features. From our internal database, 150 cases of pathologically-confirmed breast ultrasound data [Hall et al., UMB (2003)] with data augmentation are used to evaluate our machine learning models. Our initial testing results are encouraging with the accuracy and area under the curve being around 0.75.
The effects of varying ultrasound parameters on oxygen scavenging via acoustic droplet vaporization
Authors: Benton Rachel P. , Stone Kateryna , Al Rifai Nour , Clark Abigail R. , Haworth Kevin J.
Published: November 2022

Acoustic droplet vaporization (ADV) is a process that phase transitions liquid droplets into gas microbubbles via ultrasound. ADV results in oxygen scavenging from the surrounding fluid into the microbubbles. The objective of this study was to determine the effect of ultrasound parameters on oxygen scavenging. A microfluidic device was used to produce perfluoropentane droplets with a modal diameter of 1.14 ± 0.04 μm and a polydispersity index of 0.08 ± 0.02. Droplets were diluted to a concentration of 4.7 × 10−4 ± 0.4 × 10−5 ml/ml in 95% oxygenated water. The oxygen partial pressure (pO2) of the water was measured before and during ADV. An EkoSonic ultrasound catheter (2.35 MHz, 1.5 MPa peak negative pressure, 47 W pulse average power) nucleated ADV while either varying burst period or pulse duration (n = 5). Pre-ADV pO2 was 558 ± 5 mm Hg for all experiments. Peri-ADV pO2 dropped to 294 ± 6, 316 ± 10, and 356 ± 12 mmHg for a pulse duration of 17 μs and burst periods of 0.450 ms, 0.725 ms, and 1.000 ms, respectively. The peri-ADV pO2 dropped to 331 ± 14, 342 ± 10, 313 ± 10 mmHg for a burst period of 1.000 ms and pulse durations of 17.0, 23.4, and 37.9 μs, respectively. A significant difference was seen between the amount of oxygen scavenging for the lowest and highest burst periods (p = 0.0012) and pulse durations (p = 0.027).
Volatile nanodroplets for neurological applications
Authors: Lea-Banks Harriet , Wu Sheng-Kai , Meng Ying , Gouveia Flavia Venetucci , Hamani Clement , Hynynen Kullervo
Published: November 2022

While current neuromodulation techniques are invasive, inaccurate, and/or unable to penetrate deeply, focused ultrasound (FUS) offers a way to study and treat the nervous system that is non-invasive, precise, and able to reach targets deep within the brain. Using ultrasound to trigger the delivery of pharmaceuticals from nanodroplets combines the spatial precision of FUS with the temporal control of psychoactive drugs. Here, I will present our work developing ultrasound-responsive nanodroplets to deliver anesthetics in the brain for neuromodulation. This work has shown how nanodroplets, loaded with pentobarbital, can be vaporized with FUS and inhibit activity in specific brain regions. This platform is now being investigated for the treatment of several neurological and psychiatric disorders, including agitation and aggression in a model of Alzheimer’s disease.
Nanodroplets for methicillin-resistant Staphylococcus aureus (MRSA) eradication in murine diabetic wounds
Authors: Papadopoulou Virginie , Sidders Ashelyn , Lu Kuan-Yi , Velez Amanda , Durham Phillip , Bui Duyen , Dayton Paul A. , Conlon Brian , Rowe Sarah
Published: November 2022

Bacterial biofilms are the leading cause of delayed healing in chronic wounds. Aminoglycoside antibiotics, such as gentamicin (Gent), are ineffective against biofilm cells as they maintain proton motive force below the threshold for drug uptake. We employ a novel aminoglycoside adjuvant, palmitoleic acid (PA), to facilitate drug uptake. Here, we propose a dual strategy to eradicate a chronic wound infection; utilizing ultrasound-stimulated nanodroplets (US+ND) to improve the penetration of the novel drug combination Gent/PA. A chronic wound infection model was established in SKH-1 hairless mice; 6–8 week old mice were treated with streptozocin to induce diabetes. A circular wound was created on the back of the mice and infected with methicillin-resistant Staphylococcus aureus (MRSA). Wounds were treated topically with Gent and/or PA, twice daily for four days. One daily antibiotic treatment was combined with US+ND. On day 5, mice were euthanized and the wound area was excised and plated to enumerate bacterial survivors. Neither Gent nor Gent/PA reduced bacterial burden but both treatments were significantly improved by applying US+ND to improve drug penetration. Importantly, bacteria were eradiated from 3 out of the 8 wounds in the Gent/PA group that were treated with US+ND. These data show that improving the penetration of a novel anti-biofilm drug combination is a viable strategy to eradicate biofilms in chronic wounds. [Some authors are inventors on patents related to this work.]
Multiplex molecular ultrasound imaging with perfluorocarbon nanodroplets
Authors: Van Namen Austin , Jandhyala Sidhartha , Spatarelu Catalina-Paula , Luke Geoffrey P.
Published: November 2022

Because of their small size and better stability, perfluorocarbon nanodroplets (PFNDs) are emerging as an appealing alternative to microbubbles as ultrasound imaging agents. We have developed a method to simultaneously distinguish between two populations of PFNDs in the same imaging volume. The method relies on synthesizing the PFNDs to contain cores with two different boiling points. One population of PFNDs contains a perfluoropentane core (boiling point = 28 °C), while the other contains a perfluorohexane core (boiling point = 56 °C). The low-boiling-point PFNDs undergo a single liquid-to-gas phase transition in response to an acoustic vaporizing trigger, while the high-boiling-point PFNDs recondense after each acoustic trigger, enabling repeated vaporization. We have optimized a custom imaging sequence including multiple acoustic triggers that can be used to accurately differentiate between the two populations of PFNDs. The estimated relative concentration between the two nanodroplets was highly linear (R2 and gt; 0.99) in phantom studies. The high-boiling-point PFNDs were molecularly targeted to the epidermal growth factor receptor. Cell-culture results demonstrate that the non-targeted PFNDs can act as a delivery control, enabling more precise molecular imaging. Overall, these results show that multiplex ultrasound imaging could be an effective method for a variety of molecular imaging applications.
Objective identification of note-to-note transitory segments in clarinet playing
Authors: Kellison Makayle , Coyle Whitney L. , Pàmies-Vilà Montserrat
Published: November 2022

Transients are generally identified according to a user dependent set of standards—for example, one could choose a threshold that is defined between 10% and 90% of the max mouthpiece pressure or 20%–80%. However, this choice is always at the researcher’s discretion. Presented here will be an objective option for identifying the transitory region between notes when studying clarinet playing tests by using the second derivative of the envelope of the mouthpiece pressure during clarinet playing tests. This work will offer the comparison of two methods of transition classification (1) ΔT, the interval between two extrema of the second derivative mentioned above, and (2) the interval of transition found with a threshold-based method, in order to then validate that the ΔT method relates to the tongue-reed-contact duration Tc (3) the interval between the maximum and minimum slope of the first derivative of a reed vibration signal surrounding a transition. We will then show that ΔT is a reliable and repeatable replacement for the arbitrary identification options that have been available thus far.
Using the lattice Boltzmann method to study the open-pipe end correction
Authors: Temple James A. , Coyle Whitney L. , David-Sivelle Adrien
Published: November 2022

The lattice Boltzmann method (LBM) is a well-known and often used computational technique to simulate air-flow in musical instruments. Most LBM simulations in musical acoustics published in the past have used unrealistic values for air viscosity and have focused their study on other aspects of the instrument than the open-end. Due to recent experimental discoveries, it is now interesting to focus more on the behavior at the open end of the a musical instrument, such as an organ pipe, while also including realistic playing parameters and fluid characteristics. This paper will discuss the model improvements necessary to investigate the end correction of open-ended musical instruments with LBM. Comparison of results will be made with a Comsol Multiphysics model and experimental work using transmission electronic speckle pattern interferometry (TESPI).
Broadening the scope of measurement and analysis of vibrations of an organ pipe employing intensity probe, simulations, and high-speed camera
Authors: Bordoni Paolo , Kotus Jozef , Odya Piotr , Antonacci Fabio , Kostek Bozena
Published: November 2022

This paper shows an integrated approach to measure, analyze, and model phenomena occurring in an organ pipe driven by pressurized air. The aim of this paper is two-fold, i.e., to measure the pressure signal and the intensity field around the mouth by means of an intensity probe and to visualize and observe the motion of the air jet, which represents the excitation mechanism of the system. This is realized through two techniques, i.e., measurements conducted on a Bourdon organ pipe and numerical simulations of the air flow in a pipe of the same geometry. Measurements were carried out in an anechoic chamber using the Cartesian robot. Simulations were performed on a server equipped with graphical cards, and the results were visualized employing ParaVIEW software. Moreover, an analysis was conducted by observing phenomena in both audio and video signals. A high-speed camera was employed to make the jet getting out from the windway visible. This was realized using the steam that produced the reaction of dry ice and hot water. This choice has been adopted to ensure safety conditions in the measurement environment. Finally, a comparison between the sound spectrum measured and the spectrum resulted from simulations was made.
Resonant ultrasound spectroscopy and some extensions
Authors: Maynard Julian D.
Published: November 2022

Resonant ultrasound spectroscopy (RUS) is a method in which knowledge of the shape, mass, and some natural frequencies of a sample of solid material may be used to determine the elastic properties of the material. Customarily, the natural frequencies are measured by driving the sample with a sine wave in one transducer and monitoring the sample's response with a second transducer; when the frequency of the drive is swept through a natural frequency, a tuning curve is measured, from which the natural frequency and a quality factor may be determined. Usually, a Rayleigh-Ritz method involving rectangular parallelepiped or cylindrical sample shapes and polynomial basis functions is used to analyze the data to determine the elastic properties. This talk will discuss the customary method and some extensions, including: 1) overcoming a limitation that for some problematic materials (e.g., elastomers), the method can measure only one elastic constant accurately; 2) modifying the method to include piezoelectric materials; 3) overcoming the inaccuracy of the method for samples having sharp interfaces between different materials.
Resonant ultrasound spectroscopy applications: Beyond canonical geometry
Authors: Adebisi Rasheed , Lesthaeghe Tyler , Cherry Matthew , Sathish Shamachary
Published: November 2022

Resonant ultrasound spectroscopy (RUS) is a technique that uses a combination of experimentally measured resonant frequencies and physics-based computation of these frequencies to determine the entire set of single crystal elastic constants of a material. Computation of the resonances is most often accomplished using the Rayleigh–Ritz energy minimization method but this requires knowledge of mass density and analytical representation of the shape of the material. As a result, the sample will be manufactured into a canonical geometry such as cylinder or a rectangular parallelepiped such that its displacement field can be represented by a set of basis function. In this approach, deviation from a perfect canonical geometry can have a significant impact on the estimate elastic constants during the inversion. To overcome this limitation, this project describes a finite element method combined with x-ray computed tomography to model a sample with complex shape for computation of resonance frequencies and in the inversion of the elastic constants.
Dynamic characterization of fused deposition modeling-printed polymers with variable infills using homogenization techniques
Authors: Naify Christina J. , Cushing Colby W.
Published: November 2022

Fused deposition modeling (FDM) printing is a common type of additive manufacturing, which builds up a 3-D volume by laying down filament layer-by-layer. To save material and reduce weight, many commercial software packages utilize infill, which is a repeating lattice pattern with a lower density than the solid material. Users can specify the density of the lattice, as well as the geometry of lattice, with as many as a dozen pre-designed options available to choose from in some commercial software packages. The lattice designs have impact on mechanical and dynamic properties, such as speed of sound, of the finished product. Despite the strong effect on final acoustic performance of infill, until now there has not been a methodical approach to predict the relationship between infill as a design parameter and dynamic properties. In this study, we use finite element analysis to implement homogenization techniques commonly used to study metamaterials in order to predict directional sound speeds for infills over a range of densities. The base material used in the study is polylactic acid (PLA). Additionally, samples with various infills are printed and sound speeds are measured. The experimental results are compared to predicted values.
In-process volumetric sensing of defects in multiple parts during powder bed fusion using acoustics
Authors: Kizer Nathan , Reutzel Edward , Dickman Corey , Kube Christopher M.
Published: November 2022

Additively manufactured (AM) metals have been gaining popularity due to their advantages over traditionally manufactured metals. AM processes can produce complex geometries unachievable in other methods. However, AM metals remain susceptible to traditional defects such as delaminations during manufacturing. Such defects can cause to build failure or loss of part integrity making them unsuitable for many structural applications. These defects often result from incorrect selections of process parameters for particular parts. In-situ monitoring systems using ultrasonic inspection have been proposed to sense and mitigate defects. This presentation describes experimental efforts to integrate a plurality of ultrasonic transducers into powder bed fusion AM. Nine 9Cr-1Mo stainless steel parts with identical dimensions were produced using powder bed fusion. Each part was printed with various laser power and speeds to produce a range of build qualities. Nine ultrasonic transducers were integrated into the build substrate to simultaneously monitor the nine AM parts during the build. Results of these measurements will be highlighted. This demonstration indicates the potential for using ultrasound to help determine optimal process parameters for reducing defects in AM parts. Additionally, this work supports progress toward closed-loop feedback for on-the-fly corrections.
Satisfying curriculum and rewarding curiosity—A case study in recording studios for education, experimentation, and verification
Authors: Case Alexander U.
Published: November 2022

While the acoustic performance goals of a recording studio in an academic setting have much in common with those of a commercial studio, the school diverges quickly from the business. The owner, users, and activities unique to the academy shift and expand priorities, motivating additionaldesign features. Students of audio learn to practice critical thinking informed by critical listening. It is not enough, however, that recording studios for education offer spaces withbest-in-class acoustics for listening and sound recording. Present and future generations of creative recordists must master problem solving that includes acoustic sleuthing, exploring a deliberately wide vocabulary of sonic spaces on campus to prepare them for success working in the wide range of architectural forms that await them in the course of future professional work. The snapshot of acoustic features presented here is the current solution to the ever-evolving curricular demands of one successful sound recording program.
Bigger than they appear: Electronic architecture in recording studios and what that means to the musician and engineer
Authors: Berger Russ , Hornsby Mark
Published: November 2022

Technological advancements in electronic architecture (EA), and specific adaptations of that technology to the challenges of deploying it in small spaces, have made it an affordable application for recording studios. When combined with appropriate natural acoustics, this approach can achieve acoustical results not possible by treatments alone. The apparent volume, surface treatments, and resulting reverberant energy can be modified in real time beyond the constraints of the physical space, both for what the performer experiences within the space, and for what the engineer can capture in a recording. As a follow up to a paper presented in Seattle 2021, captured audio and video demonstrations from actual recording sessions of a variety of instrumentation and ensembles will illustrate EA’s practical use in the studio and what it means to the musician and the engineer.
Virtual acoustics in a modern recording studio
Authors: Woszczyk Wieslaw , King Richard , Zhang Ying-Ying , Aydin Aybar
Published: November 2022

Acoustical designs of recording studios have evolved over several decades to accommodate changes in the recording process/practice and in the available footprint of real estate. In many cases, special rooms were added to optimize acoustics for specific purpose: drum rooms, piano rooms, vocal rooms, reverb chambers, serving to isolate sounds and thus achieve better control of balance, auditory perspective, and sound color in recording. Today, workstations, plugins, and virtual acoustics setup allow for a replacement of the traditional design of a recording studio with one incorporating virtual acoustics that puts lesser demands on real estate. The talk will present a modern approach to 3D recording based on virtual assets that permits both simultaneous and sequential processes in recording of music while maximizing creative flexibility and acoustic experiences of artists.
A modern metric for acoustic clarity in critical listening environments
Authors: Swerdlow Andy
Published: November 2022

Characteristics of acoustics in small rooms have become less mysterious, more predictable and measurements more common than in past decades. Modern metrics for characterizing the acoustical performance of critical listening environments have not followed the recent predictive improvements. An Acoustic Clarity metric with a variable time window (Rear Reflection Clarity, CRR) is proposed for small (under approximately 200m3) critical listening environments such as recording studio control, mastering, film post, screening, audiophile listening, and similar rooms. The variable time window is defined by the arrival time difference between direct sound and the reflection from the rear wall, which is typically the strongest reflection and is opposite the on-axis response of the loudspeakers. Measured impulse response data collected in situ is presented and analyzed as case studies to characterize CRR. For simplicity, this presentation will focus on only the stereo components of surround-sound environments.
Assessing vocal activity patterns of leopard seals (Hydrurga leptonyx) In the Bransfield Strait, Antarctica using machine learning
Authors: Bonilla-Garzón Andrea , Madhusudhana Shyam , Dziak Robert P. , Klinck Holger
Published: November 2022

Leopard seals (Hydrurga leptonyx) are widely distributed pack-ice seals in Antarctic and sub-Antarctic waters. As apex predators, these animals play a crucial role in the Southern Ocean food web. Data on population-level changes in their abundance and distribution may be a useful indicator of ecosystem-level changes in this unique and fragile environment. Over the past few decades, many studies have conclusively shown that passive acoustic monitoring (PAM) is an effective tool to monitor the abundance and distribution of vocally active marine mammals in remote and inaccessible areas for extended periods. However, handling and analyzing the vast amount of PAM data being collected remains challenging. Within the scope of this effort, we explored the use of a machine learning algorithm (convolutional neural network; CNN) to automatically detect the ‘low double trill’; one of the most common leopard seal vocalizations, in three years of continuous acoustic data recorded in the Bransfield Strait, Antarctica between 2005 and 2008. After optimizing the algorithm, we evaluated its detection performance on various temporal scales (weeks, days, hours) to assess if CNNs are useful for monitoring leopard seal populations at ecologically relevant scales in the Southern Ocean.
Directional detection of simulated whale calls and ambient noise in a busy harbour
Authors: Binder Carolyn , Pecknold Sean , Robinson Calder L. , Martin S. B.
Published: November 2022

Timely information on marine mammal presence in, or near, sonar training areas can be used to minimize the risk of harming these animals. Defence Research and Development Canada (DRDC) has recently been investigating a variety of acoustic technologies to facilitate real-time marine mammal monitoring in high noise (including ship noise and sonar signals) environments. DRDC assessed the directional detection and localization capability of a network of sub-surface volumetric and vertical line arrays against the noisy backdrop of the busy harbour during an experiment conducted in Bedford Basin, NS. Playbacks of Southern Resident killer whale calls and North Atlantic right whale upcalls, as well as simulated calls, were transmitted. To assess variability in bearing estimates for whale calls in different frequency bands, an acoustic source was fixed at a single location for half of the experiment and dipped over the side of a boat at seven locations around the recorders during the other half. During this talk, ambient noise and environmental measurements will be presented along with acoustic localization results.
A simple approach for marine mammal noise-induced threshold shift prediction from down-the-hole piling noise exposure
Authors: Guan Shane
Published: November 2022

In assessing auditory effects on marine mammals from noise exposure, a dual-criterion is currently used by regulators to estimate the noise-induced threshold shift (NITS). Such criterion classifies anthropogenic noise into two mutually exclusive categories: Impulsive and non-impulsive. However, in real world situations, marine mammals are often exposed to complex noise field that contains both impulsive and non-impulsive components, thus makes it difficult or even impossible to accurately assess their NITS from noise exposure. One example is down-the-hole (DTH) pile installation, which generates both impulsive noise from percussive drilling/striking and non-impulsive noise from debris removal simultaneously. In this study, a relatively simple approach is proposed that employs kurtosis values to quantify the impulsiveness of two DTH piling noises datasets for six different marine mammal functional hearing groups. A kurtosis adjustment approach that has been suggested for predict human hearing loss from noise exposure was then used to build correction factors for estimation of NITS of marine mammals exposed to DTH piling noises. Further research on marine mammal NITS from complex noise exposure is needed to validate and improve this model.
Acoustic float tracking with the Kalman smoother
Authors: Chamberlain Paul , Cornuelle Bruce , Talley Lynne , Speer Kevin , Hancock Cathrine , Riser Stephen
Published: November 2022

Acoustically tracked subsurface floats provide insights into ocean complexity and were first deployed over 60 years ago. A standard tracking method uses a Least-Squares algorithm to estimate float trajectories based on acoustic ranging from moored sound sources. However, infrequent or imperfect data challenge such estimates. Acoustic tracking is currently the only feasible strategy for recovering float positions in the sea ice region, a focus of this study. Acoustic records recovered from under-ice floats frequently lack continuous sound source coverage. This is because environmental factors such as surface sound channels and sea ice attenuate acoustic signals, while operational considerations make polar sound sources difficult to deploy. Here we present a Kalman Smoother approach that, by including some estimates of float behavior, extends tracking to situations with more challenging data sets. The Kalman Smoother constructs dynamically constrained, error-minimized float tracks using all possible position data. The Kalman Smoother is applied to previously-tracked floats from the southeast Pacific (DIMES experiment), and the results are compared with existing trajectories constructed using the Least-Squares algorithm. The Kalman Smoother is also used to reconstruct the trajectories of a set of previously untracked, acoustically-enabled Argo floats in the Weddell Sea.